CN116096828A - Photocurable adhesive sheet - Google Patents

Abstract

The present invention provides an adhesive sheet which is suitable for manufacturing self-luminous display devices such as mini/micro LED display devices with improved contrast and which has excellent level difference absorbability and processability, and which has a function of preventing reflection of metal wiring and the like. The photocurable pressure-sensitive adhesive sheet of the present invention is characterized by comprising a pressure-sensitive adhesive layer that is cured by irradiation with radiation, wherein the pressure-sensitive adhesive layer comprises a colorant, the maximum value of the transmittance at a wavelength of 200 to 400nm of the pressure-sensitive adhesive layer is greater than the maximum value of the transmittance at a wavelength of 400 to 700nm, the storage modulus (G ' b 85) of the pressure-sensitive adhesive layer before curing at 85 ℃ is lower than 65kPa, and the storage modulus (G ' a 10) of the pressure-sensitive adhesive layer after curing at 10 ℃ and the storage modulus (G ' b 85) of the pressure-sensitive adhesive layer before curing at 85 ℃ satisfy the following relational expression (1). 3.3< G 'a10/G' b85 (1).

Description

Photocurable Adhesive Sheet

technical field

The present invention relates to a photocurable pressure-sensitive adhesive sheet. More specifically, it relates to a photocurable pressure-sensitive adhesive sheet suitable for sealing light-emitting elements of self-luminous display devices such as mini/micro LEDs.

Background technique

In recent years, self-luminous display devices typified by Mini/MicroLight Emitting Diode Displays have been designed as next-generation display devices. Regarding the mini/micro LED display device, as a basic structure, a substrate on which a large number of tiny LED light-emitting elements (LED chips) are arranged at a high density is used as a display panel. Covering members such as glass plates.

For self-luminous display devices such as mini/micro LED display devices, there are some methods such as white backlight method, white light-emitting color filter method, and RGB method. In the white light-emitting color filter method and RGB method, it is sometimes used as a sealing material An adhesive colored black (for example, see Patent Documents 1 to 3).

This is because the above-mentioned black adhesive contributes to preventing color mixture and improving contrast by filling between the RGB LED chips arranged on the substrate of the display panel. Reflection of metal oxides such as ITO.

In the mini/micro LED display device, LED chips are densely covered on the substrate, and there are a large number of fine height differences between the LED chips. For the sealing material used in the mini/micro LED display device, landfill is required. These height difference performances, that is, excellent height difference absorbability (also referred to as "step difference followability"). Therefore, in order to improve the level difference absorbability, the above-mentioned black adhesive needs to be designed so as to exhibit high fluidity.

On the other hand, although an adhesive exhibiting high fluidity is excellent in height difference absorbability, there is a problem that processability such as shape stability and handleability decreases. For example, a laminate having an adhesive layer exhibiting high fluidity is prone to lack of glue during cutting, and the adhesive layer tends to protrude and sag from the end during storage, and sometimes adheres to the protruded adhesive layer. Problems such as process pollution caused by foreign matter.

A photocurable adhesive (hybrid adhesive) is known as an adhesive that satisfies both the above-mentioned level difference absorption and workability (for example, see Patent Document 4). The mixed adhesive has the advantages of having high fluidity, being in a semi-cured state with excellent height difference absorbability to sufficiently follow the height difference, and then irradiating light to complete curing, thereby improving processability.

prior art literature

patent documents

Patent Document 1: Japanese Patent Laid-Open No. 2019-204905

Patent Document 2: Japanese Patent Laid-Open No. 2017-203810

Patent Document 3: Japanese PCT Publication No. 2018-523854

Patent Document 4: International Publication No. WO2016/170875

Contents of the invention

The problem to be solved by the invention

However, when the binder is mixed with carbon black or the like for coloring, for example, light cannot pass through the binder, so that curing is inhibited, making it difficult to improve processability.

The present invention has been made based on the above-mentioned situation, and an object of the present invention is to provide an adhesive sheet suitable for manufacturing mini/micro LED display devices, etc., which have an improved function of preventing reflection from metal wiring, etc., and improved contrast. It is a self-luminous display device with excellent height difference absorption and processability.

solutions to problems

The inventors of the present invention conducted intensive studies to achieve the aforementioned object, and as a result, found that the adhesive layer of the photocurable adhesive sheet exhibits absorption in the visible light region but has high transmittance in the ultraviolet region. By coloring in a self-luminous display device, the function of preventing reflection of metal wiring and the like and the contrast are improved, and excellent level difference absorption and processability can be achieved at the same time. The present invention was accomplished based on these findings.

A first aspect of the present invention provides a photocurable pressure-sensitive adhesive sheet. That is, the photocurable adhesive sheet of the first aspect of the present invention includes an adhesive layer cured by irradiation with radiation. In the photocurable pressure-sensitive adhesive sheet according to the first aspect of the present invention, the pressure-sensitive adhesive layer before curing is in a semi-cured state with high fluidity, and exhibits excellent level difference absorption. Therefore, when bonding to a display panel in which light-emitting elements (LED chips) are densely arranged, the fine height difference between the light-emitting elements (LED chips) can be sufficiently followed, and air bubbles are not left and gaps are not left. On the other hand, the above-mentioned pressure-sensitive adhesive layer after curing exhibits excellent processability. Therefore, it is possible to suppress the occurrence of gaps when cutting the laminate including the cured adhesive layer, and to suppress the occurrence of protruding and sagging of the adhesive layer from the edge during storage.

The maximum value of the transmittance in the wavelength 200-400nm of the said adhesive layer in the photocurable adhesive sheet of the 1st aspect of this invention is larger than the maximum value of the transmittance in the wavelength 400-700nm. The pressure-sensitive adhesive layer has high absorbency to visible light (wavelength: 400 to 700 nm), and is excellent in light-shielding properties. The structure in which the above-mentioned adhesive layer has excellent light-shielding properties against visible light is preferable from the viewpoint that the adhesive layer filling the fine level difference between the LED chips without gaps prevents the metal wiring on the display panel from The reflection caused by such as, prevents the color mixing of the arranged light-emitting elements (LED chips) and improves the contrast. On the other hand, the pressure-sensitive adhesive layer has high permeability to ultraviolet light (wavelength: 200 to 400 nm). The structure in which the adhesive layer has excellent ultraviolet permeability is preferable from the viewpoint that the curing reaction proceeds by irradiating the adhesive layer with ultraviolet rays and the workability of the adhesive layer improves. That is, the structure of the above-mentioned pressure-sensitive adhesive layer having a maximum value of transmittance at a wavelength of 200 to 400 nm greater than a maximum value of transmittance at a wavelength of 400 to 700 nm can achieve both excellent light-shielding properties for visible light and excellent light-shielding properties by ultraviolet irradiation. It is preferred in terms of curing reaction.

The said pressure-sensitive adhesive layer in the photocurable pressure-sensitive adhesive sheet of the 1st aspect of this invention contains a coloring agent. The aforementioned coloring agent is preferably a coloring agent whose maximum value of the transmittance at a wavelength of 200 to 400 nm is greater than the maximum value of the transmittance at a wavelength of 400 to 700 nm. This configuration is preferable from the viewpoint that the pressure-sensitive adhesive layer realizes a maximum value of the transmittance at a wavelength of 200 to 400 nm greater than the maximum value of the transmittance at a wavelength of 400 to 700 nm.

In the photocurable pressure-sensitive adhesive sheet according to the first aspect of the present invention, the storage elastic modulus (G'b85) at 85° C. of the pressure-sensitive adhesive layer before curing is less than 65 kPa. Such a configuration is preferable from the viewpoint that the pressure-sensitive adhesive layer before curing exhibits excellent height difference absorbability.

In the photocurable adhesive sheet according to the first aspect of the present invention, the storage modulus (G'a10) of the adhesive layer after curing at 10°C is the same as that of the adhesive layer before curing at 85°C. The storage modulus (G'b85) satisfies the following relational expression (1).

3.3<G'a10/G'b85 (1)

This configuration is preferable in that the pressure-sensitive adhesive layer before curing exhibits excellent height difference absorbability, and the pressure-sensitive adhesive layer after curing exhibits excellent processability.

In the photocurable pressure-sensitive adhesive sheet according to the first aspect of the present invention, the curing by radiation irradiation is preferably curing by ultraviolet irradiation of 3000 mJ/cm ² in terms of cumulative light intensity. This configuration is preferable from the viewpoint that the pressure-sensitive adhesive layer is cured by ultraviolet irradiation and exhibits excellent workability.

In the photocurable adhesive sheet according to the first aspect of the present invention, the storage elastic modulus (G'a10) at 10° C. of the adhesive layer after curing is preferably 90 kPa or more. This configuration is preferable from the viewpoint that the cured pressure-sensitive adhesive layer exhibits excellent workability.

In the photocurable pressure-sensitive adhesive sheet according to the first aspect of the present invention, the pressure-sensitive adhesive layer preferably contains a base polymer, a crosslinking agent, and a photopolymerization initiator. In this configuration, the base polymer preferably contains an acrylic polymer. Moreover, in this case, it is preferable that the said crosslinking agent contains polyfunctional (meth)acrylate. These configurations are preferable from the viewpoint that the aforementioned pressure-sensitive adhesive layer forms a crosslinked structure by the reaction of the crosslinking agent and the photopolymerization initiator by irradiation with radiation and is cured, thereby exhibiting excellent processability. In this configuration, the adhesive layer constitutes a hybrid adhesive, and the base polymer is semi-cured to such an extent that it is excellent in height difference absorbability.

In the photocurable pressure-sensitive adhesive sheet according to the first aspect of the present invention, the pressure-sensitive adhesive layer is preferably a single layer formed of the base polymer and having two opposing main surfaces, and the pressure-sensitive adhesive layer is formed of the above-mentioned When the adhesive layer of a single layer is equally divided into two parts along the thickness direction, the concentration of the aforementioned crosslinking agent and/or the aforementioned photopolymerization initiator in the region where one of the aforementioned two main surfaces, that is, the first main surface belongs, and The concentration of the crosslinking agent and/or the photopolymerization initiator is different in the region where the other, ie, the second main surface belongs. In this configuration, the single-layer adhesive layer preferably has a concentration gradient of the crosslinking agent and/or the photopolymerization initiator in the thickness direction.

The photocurable pressure-sensitive adhesive sheet of these aspects is preferably produced by a method including the following steps.

forming an adhesive layer of a single layer formed of the aforementioned base polymer,

curing the aforementioned adhesive layer,

preparing a solution of the aforementioned crosslinking agent and/or the aforementioned photopolymerization initiator,

Coating the aforementioned solution on one side of the aforementioned cured adhesive layer, allowing the aforementioned crosslinking agent and/or the aforementioned photopolymerization initiator contained in the solution to penetrate from the aforementioned one side of the aforementioned adhesive layer along the thickness direction,

The aforementioned adhesive layer is dried.

In the above constitution, a solution of the crosslinking agent and/or the photopolymerization initiator is coated on one side of the pressure-sensitive adhesive layer and penetrated, thereby generating the crosslinking agent and/or the photopolymerization initiator on the surface and the back surface of the pressure-sensitive adhesive layer. Or the concentration difference of the aforementioned photopolymerization initiator. This configuration is preferable from the viewpoint of achieving excellent level difference absorbency of the pressure-sensitive adhesive layer before curing and excellent processability of the pressure-sensitive adhesive layer after curing.

In addition, in the photocurable pressure-sensitive adhesive sheet according to the first aspect of the present invention, the pressure-sensitive adhesive layer preferably contains a polymer having a benzophenone structure in a side chain. In this configuration, the pressure-sensitive adhesive layer is preferably a cured product of a pressure-sensitive adhesive composition containing an ethylenically unsaturated compound and a polymer having a benzophenone structure in a side chain. This configuration is preferable in that the pressure-sensitive adhesive layer before curing exhibits excellent level difference absorption, and the benzophenone structure is cured by forming a crosslinked structure by ultraviolet irradiation, thereby achieving excellent processability.

In addition, the second aspect of the present invention provides a self-luminous display device including: a display panel in which a plurality of light-emitting elements are arranged on one side of a substrate, and the photocurable adhesive sheet of the first aspect of the present invention described above. The light-emitting element of the display panel is sealed by the adhesive layer of the photocurable adhesive sheet, and the adhesive layer is cured. In the self-luminous display device according to the second aspect of the present invention, the display panel may be an LED panel in which a plurality of LED chips are arranged on one side of a substrate. This configuration is preferable from the viewpoint that the adhesive having excellent light-shielding properties fills fine height differences between light-emitting elements (LED chips) without gaps in the self-luminous display device on the second side surface of the present invention. The layer can prevent reflection of metal wiring on the substrate, prevent RGB color mixing, and improve contrast.

The aforementioned self-luminous display device of the second aspect of the present invention can be produced by a method including the following steps.

A step of laminating the adhesive layer of the photocurable adhesive sheet on the first side of the present invention on a display panel in which a plurality of light emitting elements are arranged on one side of the substrate, and sealing the light emitting elements with the adhesive layer; and

A step of curing the pressure-sensitive adhesive layer by irradiating it with radiation.

Since the pressure-sensitive adhesive layer before curing has excellent level difference absorbability, it sufficiently follows the fine level difference between the light emitting elements, and adheres without remaining air bubbles and without gaps. In addition, the pressure-sensitive adhesive layer is cured by irradiating it with radiation, so that it is excellent in workability.

The radiation is preferably ultraviolet rays through which the pressure-sensitive adhesive layer exhibits transparency.

The effect of the invention

The photocurable adhesive sheet of the present invention has an adhesive layer with high light-shielding properties against visible light and excellent level difference absorption properties, and therefore can be filled in a plurality of light-emitting elements without gaps when used in the production of self-luminous display devices In the height difference between them, reflection from metal wiring is prevented, color mixing between multiple light emitting elements is suppressed, and contrast is improved. In addition, by irradiating and curing the above-mentioned pressure-sensitive adhesive layer excellent in ultraviolet transmittance, the processability is improved, the occurrence of missing glue can be suppressed during cutting, and the pressure-sensitive adhesive layer can be prevented from being cut from the edge during storage. Occurrence of overflow and sagging of the part. Therefore, by using the photocurable pressure-sensitive adhesive sheet of the present invention for the production of self-luminous display devices, it is possible to efficiently produce self-luminous display devices with improved reflection prevention functions such as metal wiring and improved contrast.

Description of drawings

FIG. 1 is a diagram (sectional view) schematically showing one embodiment of the photocurable pressure-sensitive adhesive sheet of the present invention.

FIG. 2 is a diagram (cross-sectional view) schematically showing steps for carrying out one embodiment of the method for producing a photocurable pressure-sensitive adhesive sheet of the present invention.

FIG. 3 is a diagram (cross-sectional view) schematically showing one embodiment of the photocurable pressure-sensitive adhesive sheet of the present invention.

4 is a schematic diagram (cross-sectional view) showing one embodiment of a self-luminous display device (mini/micro LED display device) of the present invention.

5 is a schematic view (cross-sectional view) showing the steps of one embodiment for carrying out the method of manufacturing a self-luminous display device (mini/micro LED display device) of the present invention.

Detailed ways

Embodiments of the present invention will be described with reference to the drawings as needed, but the present invention is not limited thereto and is merely an illustration.

[Photocurable Adhesive Sheet]

The photocurable adhesive sheet according to the first aspect of the present invention includes an adhesive layer cured by irradiation with radiation, the adhesive layer includes a colorant, and the transmittance of the adhesive layer at a wavelength of 200 to 400 nm is The maximum value of is greater than the maximum value of the transmittance at a wavelength of 400-700nm, the storage modulus (G'b85) of the aforementioned adhesive layer at 85°C before curing is lower than 65kPa, and the aforementioned adhesive layer after curing The storage modulus (G'a10) of the layer at 10°C and the storage modulus (G'b85) at 85°C before curing satisfy the following relational expression (1).

3.3<G'a10/G'b85 (1)

In this specification, the photocurable adhesive sheet of the first aspect of the present invention may be simply referred to as "photocurable adhesive sheet A". In addition, in this specification, the adhesive layer which satisfies the following (a)-(d) may be called "adhesive layer A".

(a) Curing by irradiation with radiation.

(b) The maximum value of the transmittance at a wavelength of 200 to 400 nm is greater than the maximum value of the transmittance at a wavelength of 400 to 700 nm.

(c) The storage elastic modulus (G'b85) in 85 degreeC before hardening is less than 65 kPa.

(d) The storage modulus (G'a10) at 10°C after curing and the storage modulus (G'b85) at 85°C before curing satisfy the following relational expression (1).

3.3<G'a10/G'b85 (1)

"Adhesive sheet" is considered to include "adhesive tape". That is, the photocurable adhesive sheet A may be an adhesive tape having a belt-like form.

The form of the photocurable adhesive sheet A is not particularly limited as long as it has an adhesive surface formed on the surface of the adhesive layer A. The photocurable pressure-sensitive adhesive sheet A may be a single-sided pressure-sensitive adhesive sheet in which only one side is an pressure-sensitive adhesive surface, or a double-sided pressure-sensitive adhesive sheet in which both sides are pressure-sensitive adhesive surfaces. In the case where the photocurable adhesive sheet A is a double-sided adhesive sheet, the photocurable adhesive sheet A may have a form in which two adhesive surfaces are provided by the adhesive layer A, or may have one adhesive surface provided by the adhesive layer A. The adhesive layer A is provided and the other adhesive surface is provided by an adhesive layer other than the adhesive layer A (another adhesive layer). From the viewpoint of bonding adherends together, a double-sided PSA sheet is preferred, and a double-sided PSA sheet in which both sides of the sheet are surfaces of the PSA layer A is more preferred.

The photocurable adhesive sheet A may be an adhesive sheet without a substrate (substrate layer), a so-called "substrate-less type" adhesive sheet (sometimes referred to as a "substrate-less adhesive sheet"), or It may be an adhesive sheet with a substrate (sometimes referred to as "adhesive sheet with substrate"). As the substrate-less PSA sheet in the present invention, for example, a double-sided PSA sheet consisting only of the PSA layer A, and a double-sided PSA sheet composed of the PSA layer A and other PSA layers (excluding the PSA layer) A double-sided adhesive sheet formed of an adhesive layer other than layer A). Examples of the PSA sheet with a substrate in the present invention include: a one-sided PSA sheet having an PSA layer A on one side of the substrate, a PSA sheet having an PSA layer A on both sides of the substrate The double-sided PSA sheet of A, and the double-sided PSA sheet having the PSA layer A on one side of the substrate and the other PSA layer on the other side.

Among the above, from the viewpoint of improving optical properties, a substrate-less PSA sheet is preferred, and a double-sided PSA sheet consisting of only the PSA layer A and having no substrate (substrate-free double-sided adhesive sheet) is more preferred. composite). In addition, when the PSA sheet A is a PSA sheet having a base material, it is not particularly limited, but from the viewpoint of workability, it is preferably a double-sided PSA sheet having an PSA layer A on both sides of the base material. Sheet (double-sided adhesive sheet with substrate).

In addition, the above-mentioned "substrate (substrate layer)" means that when the photocurable adhesive sheet A is used (attached) to an adherend (optical member, etc.), it is attached to the adherend together with the adhesive layer. The product part does not include the release film (release film) that is peeled off when the adhesive sheet is used (attached).

The photocurable pressure-sensitive adhesive sheet A may be a pressure-sensitive adhesive sheet with a substrate as described above. As such a base material, various optical films, such as a plastic film, an antireflection (AR) film, a polarizing plate, and a retardation plate, are mentioned, for example. Examples of raw materials for the above plastic film include polyester resins such as polyethylene terephthalate (PET), acrylic resins such as polymethyl methacrylate (PMMA), polycarbonate, triacetyl Cellulose (TAC), polysulfone, polyarylate, polyimide, polyvinyl chloride, polyvinyl acetate, polyethylene, polypropylene, ethylene-propylene copolymer, trade name "Arton" (cyclic olefin polymerized Plastic materials such as cyclic olefin-based polymers such as cyclic olefin-based polymers manufactured by JSR Corporation), trade name "ZEONOR" (cyclic olefin-based polymers, manufactured by Nippon Zeon Co., Ltd.). In addition, these plastic materials can be used individually or in combination of 2 or more types.

The aforementioned base material is preferably transparent. The total light transmittance (according to JIS K7361-1) of the substrate in the visible light wavelength region is not particularly limited, but is preferably 85% or more, more preferably 88% or more. In addition, the haze (in accordance with JIS K7136) of the base material is not particularly limited, but is preferably 1.5% or less, more preferably 1.0% or less. As such a transparent base material, non-oriented films, such as a PET film, a brand name "Arton", and a brand name "ZEONOR", etc. are mentioned, for example.

The thickness of the base material is not particularly limited, but is preferably 12 to 75 μm. It should be noted that the aforementioned substrate may have any form of single layer or multilayer. In addition, the surface of the above-mentioned base material may be suitably subjected to known conventional methods such as anti-reflection treatment such as anti-reflective treatment (AR treatment) and anti-glare treatment, physical treatment such as corona discharge treatment and plasma treatment, and chemical treatment such as primer treatment. surface treatment.

The photocurable adhesive sheet A may have another adhesive layer (an adhesive layer other than the adhesive layer A) as described above. The above-mentioned other adhesive layer is not particularly limited, and examples thereof include urethane-based adhesives, acrylic-based adhesives, rubber-based adhesives, silicone-based adhesives, and polyester-based adhesives. The adhesive layer is formed of known and commonly used adhesives such as polyamide adhesives, epoxy adhesives, vinyl alkyl ether adhesives, and fluorine adhesives. In addition, the said binder can be used individually or in combination of 2 or more types.

In addition, the photocurable adhesive sheet A may have other layers (for example, intermediate layer, primer layer, wait).

The photocurable adhesive sheet A may be provided with a release film (separator) on the adhesive surface until use. The form in which the adhesive surface of the photocurable adhesive sheet A is protected by a release film is not particularly limited, and it may be a form in which each adhesive surface is protected by two release films, or may be wound into a roll so that both sides are used to protect the adhesive surface. One sheet of release film on the release surface protects the form of each adhesive surface. The release film is used as a protective material for the adhesive layer, and is peeled off when sticking to an adherend. In addition, in the photocurable adhesive sheet A, a peeling film also plays the role as a support body of an adhesive layer. It should be noted that the release film does not need to be provided.

FIG. 1 is a diagram (sectional view) schematically showing one embodiment of the photocurable pressure-sensitive adhesive sheet A of the present invention. In FIG. 1 , 1A is the photocurable adhesive sheet of the present invention, 10 is an adhesive layer, and S1 and S2 are supports (including separators).

The thickness (total thickness) of the photocurable pressure-sensitive adhesive sheet A is not particularly limited, but is preferably 10 μm to 1 mm, more preferably 100 to 500 μm, and still more preferably 150 to 350 μm. By setting the said thickness to 10 micrometers or more, the pressure-sensitive adhesive layer A follows a step part easily, and the improvement of a step absorbability can be aimed at. In addition, the thickness of the photocurable adhesive sheet A does not include the thickness of a release film.

Since the photocurable pressure-sensitive adhesive sheet A has the above-mentioned pressure-sensitive adhesive layer A, it has light-absorptivity with respect to visible light. The total light transmittance of the photocurable adhesive sheet A is, for example, 80% or less, may be 70% or less, 60% or less, 50% or less, 40% or less, 30% or less, 20% or less, 10% or less, or 5% or less. %the following.

Since the photocurable pressure-sensitive adhesive sheet A has the pressure-sensitive adhesive layer A, it has excellent level difference absorption property before curing. For example, in addition to a height difference of 5 to 10 μm, the height difference absorbability is also excellent for a relatively high height difference exceeding 40 μm. Furthermore, it has the level difference absorbability also to the high level difference exceeding 80 micrometers.

In addition, since the photocurable adhesive sheet A has the adhesive layer A, it has excellent workability after curing, and it can suppress adhesive shortage during cutting processing and overflow and sagging of the adhesive layer from the edge during storage.

Furthermore, since the photocurable pressure-sensitive adhesive sheet A has the pressure-sensitive adhesive layer A, it is also excellent in adhesion reliability.

(adhesive layer A)

The adhesive layer A is cured by irradiation with radiation. For example, when the photocurable pressure-sensitive adhesive sheet A is attached to an adherend and the pressure-sensitive adhesive sheet is irradiated with radiation, the pressure-sensitive adhesive layer A is cured. The adhesive layer A before curing is in a state of high fluidity and has excellent height difference absorption, for example, the metal wiring layer of a self-luminous display device (mini/micro LED display device) and the light emitting element (LED chip ) between the fine height difference seal. In addition, the workability of the cured adhesive layer A by radiation irradiation is improved, and it is possible to suppress adhesive shortage during cutting, and overflow and sagging of the adhesive layer from the end during storage.

Examples of radiation for curing include ionizing radiation such as α-rays, β-rays, γ-rays, X-rays, neutron rays, and electron beams, and ultraviolet rays. Since the pressure-sensitive adhesive layer A exhibits ultraviolet ray permeability, it is preferably ultraviolet ray. Ultraviolet rays having a wavelength of 200 to 400 nm are more preferable, and ultraviolet rays having a wavelength of 330 to 400 nm are still more preferable. As a light source for ultraviolet irradiation, for example, a high-pressure mercury lamp, a low-pressure mercury lamp, a microwave excitation type lamp, a metal halide lamp, a chemical lamp, a black light lamp, or an LED can be used. In addition, the irradiation energy, irradiation time, and irradiation method of the radiation for curing can be appropriately set as long as the adhesive layer A can be cured and the adherend is not adversely affected. For example, when ultraviolet rays are used as the curing radiation, the irradiation amount (cumulative light amount) is preferably 1000 mJ/cm ² to 10000 mJ/cm ² , more preferably 2000 mJ/cm ² to 4000 mJ/cm ² , and still more preferably 3000 mJ/cm ² .

(storage modulus)

The storage modulus (G'b85) of the adhesive layer A before curing is not particularly limited at 85°C, for example, it is preferably less than 65 kPa, more preferably 60 kPa or less, further preferably 55 kPa or less, particularly preferably 50 kPa or less, Furthermore, it may be 45 kPa or less. Such a configuration is preferable from the viewpoint of realizing the excellent level difference absorbability of the pressure-sensitive adhesive layer A before curing. Moreover, G'b85 is not specifically limited, For example, it is preferably 5 kPa or more, more preferably 10 kPa or more, and still more preferably 15 kPa or more from the viewpoint of handleability and operability. The storage modulus (G'b85) of the adhesive layer A before curing at 85°C can be determined, for example, by the composition of the mixed adhesive composition described later for forming the adhesive layer A (for example, the base polymer composition described later). Molecular weight, usage amount, monomer composition, type and amount of functional group of the compound; type and amount of crosslinking agent (especially the first crosslinking agent); Mw and Tg of BP polymer; weight fraction of BP polymer; composition The composition of the monomer components of the BP polymer and the ethylenically unsaturated compound, the type and amount of the functional group; the type and amount of the crosslinking agent) and the like are adjusted.

The storage modulus (G'a10) of the cured adhesive layer A at 10°C is not particularly limited, for example, it is preferably 90 kPa or more, more preferably 100 kPa or more, more preferably 110 kPa or more, more preferably 120 kPa or more, More preferably 130 kPa or more, more preferably more than 146 kPa, more preferably 180 kPa or more, still more preferably 200 kPa or more, particularly preferably 250 kPa or more, further preferably 300 kPa or more, or 350 kPa or more. Such a configuration is preferable from the viewpoint of realizing excellent processability of the adhesive layer A after curing. Moreover, G'a10 is not specifically limited, For example, it is 5000 kPa or less, Preferably it is 2500 kPa or less, More preferably, it is 1000 kPa or less from a viewpoint of adhesion reliability. The storage modulus (G'a10) of the adhesive layer A after curing at 10°C can be determined, for example, by the composition of the mixed adhesive composition described later for forming the adhesive layer A (for example, the base polymer composition described later). Molecular weight, usage amount, monomer composition, type and amount of functional group; type and amount of crosslinking agent (especially the second crosslinking agent); Mw, Tg, BP equivalent of BP polymer (A); BP polymerization The weight fraction of the compound; the composition of the monomer components constituting the BP polymer and the ethylenically unsaturated compound, the type and amount of the functional group; the type and amount of the crosslinking agent) etc.

The ratio of the storage modulus (G'a10) of the cured adhesive layer A at 10°C to the storage modulus (G'b85) of the adhesive layer A before curing at 85°C (G 'a10/G'b85) is not particularly limited, for example, it is preferably greater than 3.3, more preferably 3.4 or greater, still more preferably 3.5 or greater, particularly preferably 3.6 or greater, further may be 3.7 or greater, 3.8 or greater, 3.9 or greater, 4 or greater, 5 or more, 6 or more, 7 or more, 8 or more, 9 or more, 10 or more, or 11 or more. Such a configuration is preferable from the viewpoint of achieving both the excellent absorbency of the pressure-sensitive adhesive layer A before curing and the excellent processability of the pressure-sensitive adhesive layer A after curing. In addition, G'a10/G'b85 is not particularly limited, but is preferably 100 or less, more preferably 50 or less, and still more preferably 30 or less from the viewpoint of handleability, operability, and adhesion reliability. The ratio of the storage modulus (G'a10) of the cured adhesive layer A at 10°C to the storage modulus (G'b85) of the adhesive layer A before curing at 85°C (G 'a10/G'b85) can be determined by, for example, the composition of the mixed adhesive composition described later for forming the adhesive layer A (for example, the molecular weight of the base polymer described later, the amount used, the monomer composition, the type of functional group, and Amount; type, amount and ratio of crosslinking agent (especially the first and second crosslinking agent); Mw, Tg, BP equivalent of BP polymer; weight fraction of BP polymer; The composition of the monomer component of the saturated compound, the type and amount of the functional group; the type and amount of the crosslinking agent) and the like are adjusted.

The storage modulus (G'b10) of the pressure-sensitive adhesive layer A before curing is not particularly limited at 10°C, but is, for example, preferably 10 kPa or more, more preferably 50 kPa or more, and still more preferably It may be 70 kPa or more, or 90 kPa or more, or 100 kPa or more. Moreover, G'b10 is not specifically limited, For example, it is 5000 kPa or less, Preferably it is 2500 kPa or less, More preferably, it is 1000 kPa or less from a viewpoint of adhesion reliability. The storage modulus (G'b10) of the adhesive layer A before curing at 10°C can be determined, for example, by the composition of the mixed adhesive composition described later for forming the adhesive layer A (for example, the base polymer composition described later). Molecular weight, usage amount, monomer composition, type and amount of functional group of the compound; type and amount of crosslinking agent (especially the first crosslinking agent); Mw and Tg of BP polymer; weight fraction of BP polymer; composition The composition of the monomer components of the BP polymer and the ethylenically unsaturated compound, the type and amount of the functional group; the type and amount of the crosslinking agent) and the like are adjusted.

The storage modulus (G'a85) of the cured adhesive layer A at 85°C is not particularly limited, but is, for example, preferably 10 kPa or more, preferably 20 kPa or more, more preferably Above 30kPa. Moreover, G'a85 is not specifically limited, For example, it is 1000 kPa or less, Preferably it is 500 kPa or less, More preferably, it is 200 kPa or less from a viewpoint of adhesion reliability. The storage modulus (G'a85) of the adhesive layer A after curing at 85°C can be determined, for example, by the composition of the mixed adhesive composition described later for forming the adhesive layer A (for example, the base polymer composition described later). Molecular weight, usage amount, monomer composition, type and amount of functional group of compound; type and amount of crosslinking agent (especially the second crosslinking agent); Mw, Tg, BP equivalent of BP polymer; weight of BP polymer Score; composition of monomer components constituting BP polymer and ethylenically unsaturated compound, type and amount of functional group; type and amount of crosslinking agent) etc. are adjusted.

The storage modulus (G'a25) of the cured adhesive layer A at 25°C is not particularly limited, for example, it is preferably 70 kPa or more, more preferably more than 100 kPa, more preferably 150 kPa or more, and even more preferably 170 kPa or more. Such a configuration is preferable from the viewpoint of realizing excellent processability of the adhesive layer A after curing. Moreover, G'a25 is not specifically limited, For example, it is 5000 kPa or less, Preferably it is 2500 kPa or less, More preferably, it is 1000 kPa or less from a viewpoint of adhesion reliability. The storage modulus (G'a25) of the adhesive layer A after curing at 25°C can be determined, for example, by the composition of the mixed adhesive composition described later for forming the adhesive layer A (for example, the base polymer composition described later). Molecular weight, usage amount, monomer composition, type and amount of functional group of compound; type and amount of crosslinking agent (especially the second crosslinking agent); Mw, Tg, BP equivalent of BP polymer; weight of BP polymer Score; composition of monomer components constituting BP polymer and ethylenically unsaturated compound, type and amount of functional group; type and amount of crosslinking agent) etc. are adjusted.

The storage modulus (G'b25) of the pressure-sensitive adhesive layer A before curing is not particularly limited at 25° C., but is, for example, 300 kPa or less, preferably 250 kPa or less, more preferably 200 kPa or less. Such a configuration is preferable from the viewpoint of realizing the excellent level difference absorbability of the pressure-sensitive adhesive layer A before curing. Moreover, G'b25 is not specifically limited, For example, it is 10 kPa or more, Preferably it is 30 kPa or more, More preferably, it is 50 kPa or more from a viewpoint of adhesion reliability. The storage modulus (G'b25) of the adhesive layer A before curing at 25°C can be determined, for example, by the composition of the mixed adhesive composition described later for forming the adhesive layer A (for example, the base polymer composition described later). Molecular weight, usage amount, monomer composition, type and amount of functional group of the compound; type and amount of crosslinking agent (especially the first crosslinking agent); Mw and Tg of BP polymer; weight fraction of BP polymer; composition The composition of the monomer components of the BP polymer and the ethylenically unsaturated compound, the type and amount of the functional group; the type and amount of the crosslinking agent) and the like are adjusted.

The ratio of the storage modulus (G'a25) of the cured adhesive layer A at 10°C to the storage modulus (G'b85) of the adhesive layer A before curing at 85°C (G 'a25/G'b85) is not specifically limited, For example, it is preferably 0.3 or more, more preferably 0.5 or more, more preferably 1 or more, more preferably more than 3, preferably 3.5 or more, more preferably 4 or more. Such a configuration is preferable from the viewpoint of achieving both the excellent absorbency of the pressure-sensitive adhesive layer A before curing and the excellent processability of the pressure-sensitive adhesive layer A after curing. Moreover, G'a25/G'b85 is not specifically limited, For example, it is 100 or less, Preferably it is 50 or less, More preferably, it is 30 or less from the viewpoint of handleability, handleability, and adhesion reliability. The ratio of the storage modulus (G'a25) of the cured adhesive layer A at 10°C to the storage modulus (G'b85) of the adhesive layer A before curing at 85°C (G 'a25/G'b85) can be determined by, for example, the composition of the mixed adhesive composition described later for forming the adhesive layer A (for example, the molecular weight, usage amount, monomer composition, type and type of the functional group of the base polymer described later). Amount; type, amount and ratio of crosslinking agent (especially the first and second crosslinking agent); Mw, Tg, BP equivalent of BP polymer; weight fraction of BP polymer; The composition of the monomer component of the saturated compound, the type and amount of the functional group; the type and amount of the crosslinking agent) and the like are adjusted.

The curing conditions in the above-mentioned "adhesive layer A after curing" are not particularly limited, but the ultraviolet ray that the adhesive layer A exhibits permeability is preferable. Ultraviolet rays having a wavelength of 200 to 400 nm are more preferable, and ultraviolet rays having a wavelength of 330 to 400 nm are still more preferable. As a light source for ultraviolet irradiation, for example, a high-pressure mercury lamp, a low-pressure mercury lamp, a microwave excitation type lamp, a metal halide lamp, a chemical lamp, a black light lamp, or an LED can be used. In addition, the irradiation energy, irradiation time, and irradiation method of the radiation for curing can be appropriately set as long as the adhesive layer A can be cured and the adherend is not adversely affected. For example, when ultraviolet rays are used as the curing radiation, the irradiation amount (cumulative light amount) is preferably 1000 mJ/cm ² to 10000 mJ/cm ² , more preferably 2000 mJ/cm ² to 4000 mJ/cm ² , and still more preferably 3000 mJ/cm ² .

In addition, the said storage modulus is the value measured by the dynamic viscoelasticity measurement.

(Other characteristics of adhesive layer A)

The gel fraction of the pressure-sensitive adhesive layer A before curing is 50 to 90% by weight, preferably 50 to 80% by weight, more preferably 50 to 70% by weight. By making the above-mentioned gel ratio 90% by weight or less, the cohesive force of the adhesive layer A decreases to some extent, and the adhesive layer A becomes soft, so the adhesive layer becomes easy to follow the height difference, and excellent Highly poor absorbency. On the other hand, by setting the above-mentioned gel ratio to 50% by weight or more, it is possible to suppress the occurrence of the problem that the adhesive layer becomes too soft and the handleability and operability of the adhesive sheet decrease. In a wet environment, the generation of air bubbles and floating can be suppressed, and the bonding reliability can be improved. The above-mentioned gel ratio can be controlled by, for example, the type, content (use amount) and the like of the above-mentioned crosslinking agent.

The above-mentioned gel ratio (ratio of solvent-insoluble components) can be obtained as ethyl acetate-insoluble components. Specifically, it was determined as the weight fraction (unit: weight %) of the insoluble matter after immersing the adhesive layer in ethyl acetate at room temperature (23° C.) for 7 days with respect to the sample before immersion. More specifically, the said gel fraction means the value calculated by the following "measuring method of gel fraction".

(Measurement method of gel fraction)

About 1 g of the pressure-sensitive adhesive layer was collected and its weight was measured, and this weight was taken as "the weight of the pressure-sensitive adhesive layer before immersion". Next, after immersing the collected adhesive layer in 40 g of ethyl acetate for 7 days, all insoluble components in ethyl acetate (insoluble parts) were recovered, and all the collected insoluble parts were dried at 130° C. for 2 hours. On the other hand, the weight was measured after removing ethyl acetate, and it was set as "the dry weight of the insoluble part" (the weight of the adhesive layer after immersion). Then, the obtained numerical value was substituted into the following formula and calculated.

Gel fraction (weight %)=[(dry weight of insoluble part)/(weight of adhesive layer before immersion)]×100

The gel ratio of the adhesive layer A before curing can be determined, for example, by the composition of the mixed adhesive composition described later for forming the adhesive layer A (for example, the molecular weight, usage amount, and monomer composition of the base polymer described later). , the type and amount of functional groups; the type and amount of cross-linking agent (especially the first cross-linking agent); the Mw and Tg of BP polymer (A); the weight fraction of BP polymer; The composition of the monomer component of the saturated compound, the type and amount of the functional group; the type and amount of the crosslinking agent), curing conditions (heating conditions, radiation irradiation conditions) and the like are adjusted.

Moreover, the glass transition temperature (Tg) of the adhesive layer A before hardening is not specifically limited, Preferably it is -60-20 degreeC, More preferably, it is -40-10 degreeC, More preferably, it is -30-0 degreeC. When the above-mentioned Tg is higher than 20° C., adhesive force cannot be developed at room temperature.

The above-mentioned Tg is not particularly limited, for example, it can be measured according to JIS K 7121 by differential scanning calorimetry (DSC) using the adhesive layer as a measurement sample. Specifically, for example, it can be measured under the conditions of -80° C. to 80° C. and a temperature increase rate of 10° C./min using, as a measuring device, a device name “Q-2000” manufactured by TA Instruments.

The thickness of the adhesive layer A is not particularly limited, and may be appropriately set so as to sufficiently seal the light-emitting elements arranged on the display panel described later. For example, the thickness of the adhesive layer A is adjusted to be 1.0 to 4.0 times, preferably 1.1 to 3.0 times, more preferably 1.2 to 2.5 times, and still more preferably 1.3 to 2.0 times the height of the light emitting element. By making the said thickness 1.0 times or more, it becomes easy for the pressure-sensitive adhesive layer A to follow a step difference, and a step difference absorbability improves. Moreover, by making the said thickness into 4.0 or less, deformation|transformation of the pressure-sensitive adhesive layer A hardly occurs, and workability improves.

The thickness of the pressure-sensitive adhesive layer A is, for example, about 10 to 500 μm, and may be 20 μm or more, 30 μm or more, 40 μm or more, or 50 μm or more. The thickness of the pressure-sensitive adhesive layer A may be 400 μm or less, 300 μm or less, 250 μm or less, or 200 μm or less. By setting the said thickness to 10 micrometers or more, the pressure-sensitive adhesive layer A follows a step part easily, and a step absorbency improves. Moreover, by making the said thickness into 500 micrometers or less, deformation|transformation of the pressure-sensitive adhesive layer A hardly occurs, and workability improves.

The maximum value of the transmittance in the wavelength 200-400nm (preferably wavelength 330-400nm) of the adhesive layer A is larger than the maximum value of the transmittance in the wavelength 400-700nm.

The pressure-sensitive adhesive layer A has lower transmittance to visible light (wavelength 400-700 nm) than the ultraviolet region (wavelength 200-400 nm, preferably wavelength 330-400 nm). Adhesive layer A with excellent light-shielding properties against visible light seals the fine level difference between the metal wiring layer and the light-emitting element (LED chip) of a self-luminous display device (mini/micro LED display device) without gaps, thereby preventing Reflection by metal wiring, etc., prevents color mixing of light emitting elements (LED chips), and improves image contrast.

On the other hand, since the adhesive layer A has higher transmittance in the ultraviolet region (wavelength 200 to 400 nm, preferably wavelength 330 to 400 nm) than visible light, it can be cured by irradiating ultraviolet rays. The processability of the pressure-sensitive adhesive layer A cured by ultraviolet irradiation is improved, and it is possible to suppress the lack of glue during cutting and the overflow and sagging of the pressure-sensitive adhesive layer from the edge during storage.

In this specification, "the maximum value of the transmittance at a wavelength of 200 to 400 nm" means the highest transmittance in the range of a wavelength of 200 to 400 nm. For example, when there is one maximum value of the transmittance in the wavelength range of 200 to 400 nm, this maximum value becomes the maximum value of the transmittance. In addition, when there is no maximum value of the transmittance in the wavelength region of 200 to 400 nm, the higher transmittance among the transmittances at the wavelength of 200 nm or 400 nm becomes the maximum value. The same applies to "the maximum value of the transmittance at a wavelength of 330 to 400 nm" and "the maximum value of the transmittance at a wavelength of 400 to 700 nm".

The maximum value of the transmittance of the adhesive layer A at a wavelength of 400 to 700 nm (visible light region) is, for example, 80% or less, may be 70% or less, 60% or less, 50% or less, 40% or less, 30% or less , 20% or less or 10% or less.

In addition, the adhesive layer A preferably has an average transmittance at a wavelength of 200 to 400 nm (preferably a wavelength of 330 to 400 nm) greater than the average transmittance at a wavelength of 400 to 700 nm. The average transmittance of the adhesive layer A at a wavelength of 400 to 700 nm (visible light region) is, for example, 80% or less, and may be 70% or less, 60% or less, 50% or less, 40% or less, 30% or less, 20% or less. % or less or less than 10%.

The pressure-sensitive adhesive layer A exhibits excellent light-shielding properties against visible light, and therefore even when a metal adherend is laminated on the pressure-sensitive adhesive layer A, reflection and gloss on the metal surface can be prevented. When the metal adherend is laminated on the pressure-sensitive adhesive layer A, the reflectance in the visible light region of 5° regular reflection is preferably 50% or less, more preferably 30% or less, still more preferably 15% or less, particularly preferably 10% the following. Gloss when a metal adherend is laminated on the adhesive layer A (based on JIS Z 8741-1997) is preferably 100% or less, more preferably 80% or less, still more preferably 60% or less, particularly preferably 50% the following.

In addition, as said metal adherend, copper, aluminum, stainless steel, etc. are mentioned.

(Colorant)

The adhesive layer A contains a colorant. As the aforementioned colorant, a colorant whose maximum value of the transmittance at a wavelength of 200 to 400 nm (preferably a wavelength of 330 to 400 nm) is greater than the maximum value of the transmittance at a wavelength of 400 to 700 nm (hereinafter sometimes referred to as "colorant") is preferable. (A)").

The maximum value of the transmittance of the adhesive layer A at a wavelength of 200 to 400 nm (preferably at a wavelength of 330 to 400 nm) is not particularly limited, and it is preferable to include Colorant A and achieved.

The maximum value of the transmittance of the colorant (including colorant A) at a wavelength of 400 to 700 nm (visible light region) is, for example, 80% or less, may be 70% or less, 60% or less, 50% or less, 40% or less , 30% or less, 20% or less, 10% or less, or 5% or less.

In addition, the colorant (including colorant A) preferably has an average transmittance at a wavelength of 200 to 400 nm (preferably a wavelength of 330 to 400 nm) greater than the average transmittance at a wavelength of 400 to 700 nm. The average transmittance of the colorant (including colorant A) at a wavelength of 400 to 700 nm (visible light region) is, for example, 80% or less, or 70% or less, 60% or less, 50% or less, 40% or less, 30% or less. % or less, 20% or less, 10% or less, or 5% or less.

Regarding the transmittance of the colorant (including the colorant A), it is possible to use an appropriate solvent such as tetrahydrofuran (THF) or a dispersion medium (with a wavelength of 200 to 700 nm) such that the transmittance at a wavelength of 400 nm is about 50 to 60%. The solution or dispersion obtained by diluting the organic solvent with small absorption range) is measured.

As long as the coloring agent (including the coloring agent A) can be dissolved or dispersed in the pressure-sensitive adhesive layer A, it may be a dye or a pigment. A dye is preferred because it can achieve low haze even when added in a small amount, has no sedimentation property like a pigment, and is easy to distribute uniformly. In addition, pigments are also preferable in terms of high color rendering properties even when added in a small amount. When a pigment is used as a colorant, it is preferably low or non-conductive. In addition, when a dye is used, it is preferably used in combination with an antioxidant or the like.

Examples of ultraviolet-transmitting black pigments include "9050BLACK", "9256BLACK", "9170BLACK", and "UVBK-0001" manufactured by Tokushiki, "UB-1" manufactured by Mitsubishi Materials Electronic Chemicals Co., Ltd., and the like. "SOC-L-0123" manufactured by Orient Chemical Industries Co., Ltd. etc. is mentioned as an ultraviolet-transparent black dye.

The content of the colorant (including colorant A) in the adhesive layer A is, for example, about 0.01 to 20 parts by weight, preferably 0.1 to 10 parts by weight, based on the type of colorant, adhesive The color tone, light transmittance, and the like of the mixture layer A may be appropriately set. The coloring agent can also be added in the form of a solution or dispersion liquid dissolved or dispersed in an appropriate solvent.

(mixed adhesive composition)

The pressure-sensitive adhesive composition used to form the pressure-sensitive adhesive layer A is not particularly limited as long as it satisfies the above characteristics (a) to (d), but is preferably a mixed pressure-sensitive adhesive composition containing a colorant (preferably colorant A).

The mixed binder is a combination of two types of polymerization initiators, crosslinking agents, or crosslinking functional groups with different curing conditions such as heat and light (in this specification, the polymerization initiator, crosslinking agent, crosslinking A functional group called "trigger (trigger)") that cures in stages.

In the mixed adhesive, first, one of the initiators (in this specification, sometimes referred to as "the first initiator") is made into a semi-cured state with high fluidity and excellent height difference absorption, thereby fully following the After that, light is irradiated to complete the curing by the other initiator (in this specification, it may be referred to as "the second initiator"), and the workability can be improved.

The mixed adhesive composition constituting the adhesive layer A is not particularly limited, and typically contains a base polymer, a crosslinking agent, and a photopolymerization initiator. Here, the base polymer is a polymer cured by the aforementioned first initiator, and the crosslinking agent and photopolymerization initiator correspond to the second initiator.

The above-mentioned base polymer is not particularly limited as long as it has adhesiveness usable for optical applications. For example, an acrylic polymer contained as a base polymer in an acrylic pressure-sensitive adhesive layer, a rubber-based pressure-sensitive adhesive layer (natural rubber-based pressure-sensitive adhesive layer, synthetic rubber-based pressure-sensitive adhesive layer, etc.) The rubber-based polymer contained in the silicone-based adhesive layer, the silicone-based polymer contained in the base polymer, the polyester-based polymer contained in the polyester-based adhesive layer, and urethane The urethane-based polymer contained in the ester-based adhesive layer as the base polymer, the polyamide-based polymer contained in the polyamide-based adhesive layer as the base polymer, and the epoxy-based adhesive layer as Epoxy-based polymer contained in the base polymer, vinyl alkyl ether-based adhesive layer contained in the base polymer, vinyl alkyl ether-based polymer contained in the base polymer, and fluorine-based adhesive layer contained in the base polymer Among the fluorine-based polymers, etc., which are appropriately selected and used, any one of these polymers may be used alone or in combination of two or more. From the viewpoint of processability, durability, etc., it is preferable to use an acrylic polymer. The aforementioned acrylic polymer is not particularly limited, but is preferably a homopolymer or a copolymer of a monomer mainly composed of an alkyl (meth)acrylate. Here, the expression "(meth)acrylic acid" is used to mean either one or both of "acrylic acid" and "methacrylic acid", and the same applies to other cases. In the present invention, the term "acrylic polymer" is used in the sense of including other monomers copolymerizable with the above-mentioned alkyl (meth)acrylate.

The acrylic polymer preferably contains a monomer derived from an alkyl acrylate having a linear or branched alkyl group and/or an alkyl methacrylate having a linear or branched alkyl group. unit as the most major monomer unit by weight ratio.

Alkyl (meth)acrylate having a linear or branched alkyl group as a monomer unit for forming the acrylic polymer, that is, a monomer component for forming the acrylic polymer The alkyl (meth)acrylate containing a linear or branched alkyl group includes, for example, methyl (meth)acrylate, ethyl (meth)acrylate, propylene (meth)acrylate, ester, isopropyl (meth)acrylate, n-butyl (meth)acrylate, sec-butyl (meth)acrylate, isobutyl (meth)acrylate, tert-butyl (meth)acrylate, (meth) ) pentyl acrylate, isoamyl (meth)acrylate, hexyl (meth)acrylate, heptyl (meth)acrylate, octyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, Isooctyl (meth)acrylate, nonyl (meth)acrylate, isononyl (meth)acrylate, decyl (meth)acrylate, isodecyl (meth)acrylate, undecyl (meth)acrylate Alkyl esters, lauryl (meth)acrylate, tridecyl (meth)acrylate, tetradecyl (meth)acrylate, pentadecyl (meth)acrylate, (meth)acrylate base) cetyl acrylate, heptadecyl (meth)acrylate, stearyl (meth)acrylate, isostearyl (meth)acrylate, nonadecyl (meth)acrylate An alkyl (meth)acrylate having a linear or branched alkyl group having 1 to 20 carbon atoms, such as ester and eicosyl (meth)acrylate. As the alkyl (meth)acrylate used for the acrylic polymer, one type of alkyl (meth)acrylate may be used, or two or more types of alkyl (meth)acrylate may be used. In the present embodiment, as the alkyl (meth)acrylate used for the acrylic polymer, one selected from the group consisting of n-butyl acrylate, 2-ethylhexyl acrylate and isostearyl acrylate is preferably used. at least one.

The proportion of monomer units derived from alkyl (meth)acrylate having a linear or branched alkyl group in the acrylic polymer is preferably 50% by weight or more, more preferably 60% by weight or more , more preferably 70% by weight or more, more preferably 80% by weight or more, more preferably 90% by weight or more. That is, the ratio of the alkyl (meth)acrylate in the monomer component composition of the raw material used to form the acrylic polymer is preferably 50% by weight or more, more preferably 60% by weight or more, more preferably 70% by weight or more, more preferably 80% by weight or more, more preferably 90% by weight or more.

The aforementioned acrylic polymer may contain a monomer unit derived from an alicyclic monomer. As the alicyclic monomer used to form the monomer unit of the acrylic polymer, that is, the alicyclic monomer contained in the monomer component used to form the acrylic polymer, for example, (methyl) Cycloalkyl acrylates, (meth)acrylates having a bicyclic hydrocarbon ring, and (meth)acrylates having a tricyclic or higher hydrocarbon ring. Examples of cycloalkyl (meth)acrylates include cyclopentyl (meth)acrylate, cyclohexyl (meth)acrylate, cycloheptyl (meth)acrylate, and cyclooctyl (meth)acrylate. . As (meth)acrylate which has a bicyclic hydrocarbon ring, bornyl (meth)acrylate and isobornyl (meth)acrylate are mentioned, for example. Examples of (meth)acrylates having hydrocarbon rings having three or more rings include dicyclopentyl (meth)acrylate, dicyclopentyloxyethyl (meth)acrylate, and tricyclopentyl (meth)acrylate. Cyclopentyl ester, 1-adamantyl (meth)acrylate, 2-methyl-2-adamantyl (meth)acrylate and 2-ethyl-2-adamantyl (meth)acrylate . As the alicyclic monomer used in the acrylic polymer, one type of alicyclic monomer may be used, or two or more alicyclic monomers may be used. In the present embodiment, as the alicyclic monomer used for the acrylic polymer, it is preferable to use one selected from the group consisting of cyclohexyl acrylate, cyclohexyl methacrylate, isobornyl acrylate, and isobornyl methacrylate. at least one of .

From the viewpoint of realizing moderate flexibility in the base polymer comprising the acrylic polymer, the ratio of monomer units derived from alicyclic monomers in the acrylic polymer is preferably 5 to 60 % by weight, more preferably 10 to 50% by weight, more preferably 12 to 40% by weight. In addition, in some embodiments of the present invention, the aforementioned acrylic polymer may not contain a monomer unit derived from an alicyclic monomer.

The aforementioned acrylic polymer may contain a monomer unit derived from a hydroxyl group-containing monomer. A hydroxyl group-containing monomer is a monomer having at least one hydroxyl group within the monomer unit. When the acrylic polymer in the base polymer contains a hydroxyl group-containing monomer unit, it is easy to obtain adhesiveness and moderate cohesive force in the base polymer. Moreover, a hydroxyl group can also become a reaction point with the crosslinking agent mentioned later.

As the hydroxyl group-containing monomer used to form the monomer unit of the acrylic polymer, that is, the hydroxyl group-containing monomer contained in the monomer component used to form the acrylic polymer, for example, a hydroxyl group-containing (methyl base) acrylates, vinyl alcohol and allyl alcohol. Examples of hydroxyl-containing (meth)acrylates include 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, (meth)acrylate, base) 4-hydroxybutyl acrylate, 6-hydroxyhexyl (meth)acrylate, hydroxyoctyl (meth)acrylate, hydroxydecyl (meth)acrylate, hydroxylauryl (meth)acrylate and (meth) ) (4-hydroxymethylcyclohexyl)methyl acrylate. As the hydroxyl group-containing monomer used in the acrylic polymer, one type of hydroxyl group-containing monomer may be used, or two or more types of hydroxyl group-containing monomers may be used. In this embodiment, as the hydroxyl group-containing monomer used in the acrylic polymer, it is preferable to use a monomer selected from 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl acrylate, 2-hydroxypropyl methacrylate, At least one selected from the group consisting of hydroxypropyl, 4-hydroxybutyl acrylate and 4-hydroxybutyl methacrylate.

The ratio of monomer units derived from hydroxyl-containing monomers in the acrylic polymer is preferably 1% by weight or more, more preferably 2% by weight or more, more preferably 3% by weight or more, more preferably 7% by weight or more , more preferably 10% by weight or more, more preferably 15% by weight or more. The ratio of the monomer unit derived from the hydroxyl group-containing monomer in the acrylic polymer is preferably 35% by weight or less, more preferably 30% by weight or less. These configurations related to the ratio of the hydroxyl group-containing monomer are suitable for realizing adhesiveness and moderate cohesive force in the base polymer formed of the acrylic polymer.

The aforementioned acrylic polymer may contain a monomer unit derived from a nitrogen atom-containing monomer. A nitrogen atom-containing monomer is a monomer having at least one nitrogen atom within the monomer unit. When the acrylic polymer in the base polymer contains a nitrogen atom-containing monomer unit, it is easy to obtain hardness and good adhesion reliability in the base polymer.

As the nitrogen-atom-containing monomer used to form the monomer unit of the acrylic polymer, that is, the nitrogen-atom-containing monomer contained in the monomer component used to form the acrylic polymer, for example, N-ethylene Cyclic amides and (meth)acrylamides.

As the N-vinyl cyclic amide as a nitrogen atom-containing monomer, for example, an N-vinyl cyclic amide represented by the general formula (1) can be used.

Here, in the general formula (1), R ¹ is a divalent organic group, specifically -(CH ₂ ) _n -. n is an integer of 2-7 (preferably 2, 3 or 4).

Examples of the aforementioned N-vinyl cyclic amides include N-vinyl-2-pyrrolidone, N-vinyl-2-piperidone, N-vinyl-3-morpholinone, N-vinyl-2- - caprolactam, N-vinyl-1,3-oxazin-2-one and N-vinyl-3,5-morpholinedione.

Examples of (meth)acrylamides that are monomers containing nitrogen atoms include (meth)acrylamide, N-ethyl (meth)acrylamide, N-isopropyl (meth)acrylamide, N-butyl (meth)acrylamide, N-octyl (meth)acrylamide, N,N-dimethyl (meth)acrylamide, N,N-diethyl (meth)acrylamide , N,N-dipropyl(meth)acrylamide and N,N-diisopropyl(meth)acrylamide. As the nitrogen atom-containing monomer used in the acrylic polymer, one kind of nitrogen atom-containing monomer may be used, or two or more kinds of nitrogen atom-containing monomers may be used. In the present embodiment, N-vinyl-2-pyrrolidone is preferably used as the nitrogen atom-containing monomer used in the acrylic polymer.

From the viewpoint of realizing moderate hardness and adhesiveness in the base polymer comprising the acrylic polymer, the ratio of monomer units derived from nitrogen-atom-containing monomers in the acrylic polymer is preferably 1% by weight or more, more preferably 3% by weight or more, more preferably 5% by weight or more. In addition, from the viewpoint of suppressing the base polymer formed from the acrylic polymer from becoming too hard and achieving good adhesion reliability, the unit derived from the nitrogen-atom-containing monomer in the acrylic polymer The ratio of the monomer unit is preferably 30% by weight or less, more preferably 25% by weight or less. In addition, in some embodiments of the present invention, the aforementioned acrylic polymer may not contain a monomer unit derived from a nitrogen atom-containing monomer.

The aforementioned acrylic polymer may contain a monomer unit derived from a carboxyl group-containing monomer. A carboxyl group-containing monomer is a monomer having at least one carboxyl group within the monomer unit. When the acrylic polymer in the base polymer contains a carboxyl group-containing monomer unit, good adhesion reliability may be obtained in the base polymer. In addition, the carboxyl group can also serve as a reaction point with a crosslinking agent described later.

As the carboxyl group-containing monomer used to form the monomer unit of the acrylic polymer, that is, the carboxyl group-containing monomer contained in the monomer component used to form the acrylic polymer, for example, (meth)acrylic acid , itaconic acid, maleic acid, fumaric acid, crotonic acid and isocrotonic acid. As the carboxyl group-containing monomer used in the acrylic polymer, one kind of carboxyl group-containing monomer may be used, or two or more kinds of carboxyl group-containing monomers may be used. In the present embodiment, acrylic acid is preferably used as the carboxyl group-containing monomer used in the acrylic polymer.

From the viewpoint of obtaining the contribution of the interaction between the polar group and the carboxyl group when the polar group is present on the surface of the adherend in the base polymer containing the acrylic polymer, and ensuring good adhesion reliability The ratio of the monomer unit derived from the carboxyl group-containing monomer in the acrylic polymer is preferably 0.1% by weight or more, more preferably 0.5% by weight or more. In addition, from the viewpoint of suppressing the base polymer formed from the acrylic polymer from becoming too hard and achieving good adhesion reliability, the monomer derived from the carboxyl group-containing monomer in the acrylic polymer The ratio of the unit is preferably 20% by weight or less, more preferably 15% by weight or less. In addition, the above-mentioned acrylic polymer may not substantially contain a carboxyl group-containing monomer as its constituent monomer unit from the viewpoint of metal corrosion prevention or the like. Substantially not containing a carboxyl group-containing monomer means intentionally not using a carboxyl group-containing monomer, preferably 0.05% by weight or less (for example, 0 to 0.05% by weight), more preferably 0.01% by weight or less (for example, 0 to 0.01% by weight), When it is more preferably 0.001% by weight or less (for example, 0 to 0.001% by weight), it can be said that it does not contain substantially.

The aforementioned acrylic polymer may be a partial polymer of a mixture of monomer components constituting the acrylic polymer. In addition, the above-mentioned acrylic polymer may be obtained by adding the remaining monomer components to a partial polymer of a mixture of some monomer components constituting the acrylic polymer. The above-mentioned "partial polymer of a mixture of monomer components" means a composition in which one or more monomer components constituting the monomer components are partially polymerized.

The aforementioned base polymer may contain a crosslinking agent. The above-mentioned base polymer has a cross-linked structure due to the cross-linking agent, thereby increasing the viscosity, improving the shape stability, and forming the pressure-sensitive adhesive layer A easily. Examples of the crosslinking agent include polyfunctional (meth)acrylates and thermosetting crosslinking agents which are copolymerizable crosslinking agents (photocurable crosslinking agents) for acrylic polymers. The aforementioned base polymer may have a crosslinked structure derived only from a polyfunctional (meth)acrylate, may have a crosslinked structure derived only from a thermosetting crosslinking agent, or may have a crosslinked structure derived from a polyfunctional (meth)acrylate The crosslinked structure of both the thermosetting crosslinker and the thermosetting crosslinker.

In addition, this crosslinking agent is a crosslinking agent (1st crosslinking agent) which comprises a 1st initiator when the adhesive layer A of this invention consists of a mixed adhesive composition. That is, the base polymer having a crosslinked structure derived from the first crosslinking agent is in a semi-cured state with high fluidity, and exhibits excellent height difference absorbability.

Examples of polyfunctional (meth)acrylates as copolymerizable crosslinking agents (photocurable crosslinking agents) include 1,6-hexanediol di(meth)acrylate, butanediol di(meth)acrylate Acrylates, (poly)ethylene glycol di(meth)acrylate, (poly)propylene glycol di(meth)acrylate, neopentyl glycol di(meth)acrylate, pentaerythritol di(meth)acrylate, Pentaerythritol tri(meth)acrylate, dipentaerythritol hexa(meth)acrylate, trimethylolpropane tri(meth)acrylate, tetramethylolmethane tri(meth)acrylate, (meth)acrylic acid Allyl ester and vinyl (meth)acrylate. As the polyfunctional (meth)acrylate used for the acrylic polymer, one type of polyfunctional (meth)acrylate may be used, or two or more types of polyfunctional (meth)acrylate may be used. In this embodiment, as the polyfunctional (meth)acrylate used for the acrylic polymer, it is preferable to use a polyfunctional (meth)acrylate selected from 1,6-hexanediol diacrylate, dipentaerythritol hexaacrylate, trimethylolpropane triacrylate At least one of the group consisting of ester and polypropylene glycol diacrylate.

The ratio of monomer units derived from polyfunctional (meth)acrylates in the acrylic polymer is preferably 0.005% by weight or more, more preferably 0.01% by weight or more, more preferably 0.03% by weight or more, and more preferably 0.03% by weight or more. 0.05% by weight or more. The ratio of the monomer unit derived from a polyfunctional (meth)acrylate in the acrylic polymer is preferably 1% by weight or less, more preferably 0.5% by weight or less. These configurations related to the ratio of the polyfunctional (meth)acrylate are essential for achieving moderate hardness, adhesiveness, shape stability, and excellent height difference absorption in the base polymer formed of the acrylic polymer. Words are appropriate.

Examples of thermosetting crosslinking agents include isocyanate crosslinking agents, epoxy crosslinking agents, metal chelate crosslinking agents, melamine crosslinking agents, peroxide crosslinking agents, and urea crosslinking agents. agent, metal alkoxide-based cross-linking agent, metal salt-based cross-linking agent, carbodiimide-based cross-linking agent, oxazoline-based cross-linking agent, aziridine-based cross-linking agent and amine-based cross-linking agent. The base polymer may contain one kind of the thermosetting crosslinking agent, or may contain two or more kinds of the thermosetting crosslinking agent. It is preferable to use at least one selected from the group consisting of isocyanate-based crosslinking agents and epoxy-based crosslinking agents.

Examples of the isocyanate-based crosslinking agent include lower aliphatic polyisocyanates, alicyclic polyisocyanates, and aromatic polyisocyanates. Examples of lower aliphatic polyisocyanates include 1,2-ethylene diisocyanate, 1,4-butylene diisocyanate, and 1,6-hexamethylene diisocyanate. Examples of alicyclic polyisocyanates include cyclopentylene diisocyanate, cyclohexylene diisocyanate, isophorone diisocyanate, hydrogenated toluene diisocyanate, and hydrogenated xylene diisocyanate. Examples of aromatic polyisocyanates include 2,4-toluene diisocyanate, 2,6-toluene diisocyanate, 4,4'-diphenylmethane diisocyanate, and xylylene diisocyanate. In addition, examples of the isocyanate-based crosslinking agent include trimethylolpropane/toluene diisocyanate adduct (trade name "CORONATE L", manufactured by Nippon Polyurethane Industry Co., Ltd.), trimethylolpropane/hexamethylene diisocyanate adduct (trade name "CORONATE HL", manufactured by Nippon Polyurethane Industry Co., Ltd.) and trimethylolpropane/xylylene diisocyanate adduct (trade name "TAKENATE D-110N", manufactured by Mitsui Chemicals Co., Ltd.) and other commercially available products.

Examples of epoxy-based crosslinking agents (polyfunctional epoxy compounds) include N,N,N',N'-tetraglycidyl-m-xylylenediamine, diglycidylaniline, 1,3- Bis(N,N-diglycidylaminomethyl)cyclohexane, 1,6-hexanediol diglycidyl ether, neopentyl glycol diglycidyl ether, ethylene glycol diglycidyl ether, propylene glycol diglycidyl ether Glyceryl ether, Polyethylene glycol diglycidyl ether, Polypropylene glycol diglycidyl ether, Sorbitol polyglycidyl ether, Glycerin polyglycidyl ether, Pentaerythritol polyglycidyl ether, Polyglycerol polyglycidyl ether, Sorbitan polyglycidyl ether Glyceryl ether, trimethylolpropane polyglycidyl ether, diglycidyl adipate, diglycidyl phthalate, triglycidyl-tris(2-hydroxyethyl)isocyanurate, m- Hydroquinone diglycidyl ether and bisphenol-S-diglycidyl ether. Moreover, the epoxy-type resin which has two or more epoxy groups is also mentioned as an epoxy-type crosslinking agent. In addition, as an epoxy-type crosslinking agent, a commercial item, such as a brand name "TETRAD DC" (made by Mitsubishi Gas Chemical Co., Ltd.), is mentioned.

When the above-mentioned thermosetting crosslinking agent for crosslinking the base polymers is included, the shape stability of the base polymer is improved, the adhesive layer A is easily formed, and sufficient adhesion to the adherend is realized reliably. The content of the thermosetting crosslinking agent in the base polymer is preferably 0.001 parts by weight or more, more preferably 0.01 parts by weight or more. In addition, from the viewpoint of developing moderate flexibility in the base polymer, achieving good adhesive force, and excellent height difference absorbability, the content of the thermosetting crosslinking agent relative to the total amount of monomer components constituting the base polymer 100 parts by weight is preferably 10 parts by weight or less, more preferably 5 parts by weight or less.

When the aforementioned base polymer contains the aforementioned acrylic polymer as a binder, the content of the acrylic polymer in the base polymer is, for example, 85 to 100% by weight.

The above-mentioned base polymer may contain a polymerization initiator in addition to a monomer for forming an acrylic polymer and a crosslinking agent. As a polymerization initiator, a photopolymerization initiator and a thermal polymerization initiator are mentioned. The aforementioned base polymer may contain one kind of polymerization initiator, or may contain two or more kinds of polymerization initiators.

In addition, this polymerization initiator is a polymerization initiator (1st polymerization initiator) which comprises a 1st initiator when the adhesive layer A of this invention is formed from a mixed adhesive composition.

Examples of the aforementioned photopolymerization initiator include benzoin ether-based photopolymerization initiators, acetophenone-based photopolymerization initiators, α-ketol-based photopolymerization initiators, aromatic sulfonyl chloride-based photopolymerization initiators, Photoactive oxime-based photopolymerization initiators, benzoin-based photopolymerization initiators, benzil-based photopolymerization initiators, benzophenone-based photopolymerization initiators, ketal-based photopolymerization initiators, and thioxanthone-based photopolymerization initiators polymerization initiator. Examples of benzoin ether-based photopolymerization initiators include benzoin methyl ether, benzoin ethyl ether, benzoin propyl ether, benzoin isopropyl ether, benzoin isobutyl ether, and 2,2- Dimethoxy-1,2-diphenylethan-1-one. Examples of the acetophenone-based photopolymerization initiator include 2,2-diethoxyacetophenone, 2,2-dimethoxy-2-phenylacetophenone, 1-hydroxycyclohexylphenyl ketones, 4-phenoxydichloroacetophenone and 4-(tert-butyl)dichloroacetophenone. Examples of α-ketol-based photopolymerization initiators include 2-methyl-2-hydroxypropiophenone and 1-[4-(2-hydroxyethyl)phenyl]-2-methylpropane-1- ketone. As an aromatic sulfonyl chloride type photoinitiator, 2-naphthalenesulfonyl chloride is mentioned, for example. Examples of the photoactive oxime-based photopolymerization initiator include 1-phenyl-1,1-propanedione-2-(O-ethoxycarbonyl)-oxime. As a benzoin type photoinitiator, benzoin is mentioned, for example. As a benzil type photoinitiator, benzil is mentioned, for example. Examples of benzophenone-based photopolymerization initiators include benzophenone, benzoylbenzoic acid, 3,3'-dimethyl-4-methoxybenzophenone, and polyvinyldiphenyl ketone. As a ketal type photoinitiator, benzil dimethyl ketal is mentioned, for example. Examples of thioxanthone-based photopolymerization initiators include thioxanthone, 2-chlorothioxanthone, 2-methylthioxanthone, 2,4-dimethylthioxanthone, and isopropylthioxanthone , 2,4-diisopropylthioxanthone and dodecylthioxanthone.

The amount of the photopolymerization initiator used is not particularly limited, for example, it is preferably 0.001 to 1 part by weight, more preferably 0.01 to 0.50 parts by weight.

As a thermal polymerization initiator, an azo type polymerization initiator, a peroxide type polymerization initiator, a redox type polymerization initiator etc. are mentioned, for example. Examples of the azo polymerization initiator include 2,2'-azobisisobutyronitrile (AIBN), 2,2'-azobis-2-methylbutyronitrile (AMBN), 2,2' -Dimethyl azobis(2-methylpropionate), 4,4'-azobis-4-cyanovaleric acid, 2,2'-azobis(4-methoxy-2,4 -Dimethylvaleronitrile), 2,2'-azobis(2,4-dimethylvaleronitrile), 1,1'-azobis(cyclohexane-1-carbonitrile), 2,2 '-Azobis(2,4,4-trimethylpentane), etc. Examples of peroxide-based polymerization initiators include benzoyl peroxide, tert-butyl hydroperoxide, di-tert-butyl peroxide, tert-butyl peroxybenzoate, dicumyl peroxide, 1 , 1-bis(tert-butyl peroxide)-3,3,5-trimethylcyclohexane, 1,1-bis(tert-butyl peroxide)cyclododecane, etc.

The amount of the thermal polymerization initiator used is not particularly limited, for example, it is preferably 0.05 to 0.5 parts by weight, more preferably It is 0.1-0.3 weight part.

As a crosslinking agent contained in the mixed adhesive composition which comprises adhesive layer A, the polyfunctional (meth)acrylate which is said copolymerization crosslinking agent (photocurable crosslinking agent) is mentioned. In addition, this crosslinking agent is a crosslinking agent (2nd crosslinking agent) which comprises a 2nd initiator when the adhesive layer A of this invention consists of a mixed adhesive composition. That is, the base polymer cured by the second crosslinking agent exhibits excellent processability.

The content of the polyfunctional (meth)acrylate as the second crosslinking agent is not particularly limited, but is preferably 0.1 parts by weight relative to 100 parts by weight of the base polymer from the viewpoint of being able to impart excellent processability to the cured base polymer. It is not less than one part by weight, more preferably not less than 1 part by weight, more preferably not less than 2 parts by weight, more preferably not less than 4 parts by weight. In addition, the content of the polyfunctional (meth)acrylate is preferably 60 parts by weight or less, more preferably 40 parts by weight or less, based on 100 parts by weight of the base polymer. These configurations related to the content of the polyfunctional (meth)acrylate as the second crosslinking agent are suitable for realizing excellent processability by curing the base polymer formed of the acrylic polymer.

As a photoinitiator contained in the mixed adhesive composition which comprises adhesive layer A, the thing similar to the said photoinitiator is mentioned. In addition, this photoinitiator is a polymerization initiator (2nd polymerization initiator) which comprises a 2nd initiator when the adhesive layer A of this invention consists of a hybrid adhesive composition. That is, the base polymer cured by the photopolymerization initiator as the second polymerization initiator achieves excellent processability.

The content of the photopolymerization initiator as the second polymerization initiator is not particularly limited, but is preferably 0 to 2 parts by weight with respect to 100 parts by weight of the base polymer from the viewpoint of being able to impart excellent processability to the cured base polymer. , More preferably 0.005 to 1.5 parts by weight. These configurations related to the content of the photopolymerization initiator as the second polymerization initiator are suitable for realizing excellent processability by curing the base polymer formed of the acrylic polymer.

The mixed adhesive composition constituting the adhesive layer A may further contain ultraviolet absorbers, antirust agents, antistatic agents, crosslinking accelerators, silane coupling agents, tackifying resins, antiaging agents, and fillers as needed. , antioxidants, chain transfer agents, plasticizers, softeners, surfactants, polyols, solvents and other additives. Examples of tackifier resins include rosin derivatives, polyterpene resins, petroleum resins, and oil-soluble phenols.

The mixed adhesive composition constituting the adhesive layer A may contain a silane coupling agent within a range not impairing the effects of the present invention. When the adhesive layer A contains a silane coupling agent, the adhesion reliability to glass (particularly, the adhesion reliability to glass under a high-temperature and high-humidity environment) is improved, which is preferable.

The aforementioned silane coupling agent is not particularly limited, and preferred examples include γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropyltriethoxysilane, γ-aminopropyltrimethyl Oxysilane, N-phenyl-aminopropyltrimethoxysilane, etc. Among them, γ-glycidoxypropyltrimethoxysilane is preferable. Moreover, as a commercial item, a brand name "KBM-403" (made by Shin-Etsu Chemical Co., Ltd.) is mentioned, for example. In addition, a silane coupling agent can be used individually or in combination of 2 or more types.

The content of the silane coupling agent in the mixed adhesive composition constituting the adhesive layer A is not particularly limited, but is preferably 0.01 to 1 part by weight, more preferably 0.03 to 0.5 part by weight, based on 100 parts by weight of the base polymer. .

The mixed adhesive composition constituting the adhesive layer A may contain a polyhydric alcohol within a range not impairing the effect of the present invention. When the pressure-sensitive adhesive layer A contains a polyhydric alcohol, for example, a crosslinked structure is formed by the first crosslinking agent (particularly, the aforementioned thermosetting crosslinking agent), and the height difference absorbability is improved, which is preferable.

The aforementioned polyol is not particularly limited, and examples thereof include polyester polyol, polycarbonate polyol, polyacrylic polyol, polyether polyol, epoxy polyol, polyolefin polyol, polyether ester polyol, and the like. . Moreover, as a commercial item, a brand name "Adeka polyether EPD-300" (made by ADEKA Corporation) is mentioned, for example. In addition, polyhydric alcohol can be used individually or in combination of 2 or more types.

The content of the polyhydric alcohol in the mixed adhesive composition constituting the adhesive layer A is not particularly limited, but is preferably 0.01 to 1 part by weight, more preferably 0.03 to 0.5 part by weight, based on 100 parts by weight of the base polymer.

In addition, the mixed adhesive composition constituting the adhesive layer A may contain a solvent. The solvent is not particularly limited, and examples thereof include: esters such as ethyl acetate and n-butyl acetate; aromatic hydrocarbons such as toluene and benzene; aliphatic hydrocarbons such as n-hexane and n-heptane; cyclohexane, methyl Cyclohexane and other alicyclic hydrocarbons; organic solvents such as methyl ethyl ketone, methyl isobutyl ketone and other ketones. In addition, a solvent can be used individually or in combination of 2 or more types.

The method for forming the pressure-sensitive adhesive layer A is not particularly limited, but a first embodiment includes applying (coating) the mixed pressure-sensitive adhesive composition on a support and drying the obtained pressure-sensitive adhesive layer. Curing: The aforementioned mixed adhesive is coated (coated) on a support, and the obtained adhesive layer is irradiated with active energy rays to be cured. If necessary, heating and drying may be further performed.

It should be noted that the above-mentioned drying and curing, active energy ray irradiation, and heating and drying need to be selected so that only the curing based on the crosslinking agent and polymerization initiator constituting the first initiator proceeds and the curing based on the crosslinking agent constituting the second initiator, light Conditions under which the curing reaction of the polymerization initiator does not proceed or is inhibited.

Although it does not specifically limit as said support body, A plastic film is preferable. Examples of raw materials for the aforementioned plastic film include polyester resins such as polyethylene terephthalate (PET), acrylic resins such as polymethyl methacrylate (PMMA), polycarbonate, triacetyl Cellulose (TAC), polysulfone, polyarylate, polyimide, polyvinyl chloride, polyvinyl acetate, polyethylene, polypropylene, ethylene-propylene copolymer, trade name "Arton" (cyclic olefin polymerized Plastic materials such as cyclic olefin-based polymers such as cyclic olefin-based polymers manufactured by JSR Corporation), trade name "ZEONOR" (cyclic olefin-based polymers, manufactured by Nippon Zeon Co., Ltd.). It should be noted that these plastic materials may be used only by one type, or two or more types may be used.

The aforementioned support body may be a release sheet. It does not specifically limit as said peeling sheet, For example, the plastic film etc. which surface-treated with a peeling agent, such as a silicone type, a long-chain alkyl type, a fluorine type, and molybdenum sulfide, are mentioned.

Coating (coating) of the mixed adhesive composition can be performed by a known coating method, for example, gravure roll coater, reverse roll coater, lap coater, dip roll coater, rod coater, etc. , Blade coater, spray coater, comma coater, direct coater and other coating machines.

The drying and curing temperature is preferably 40 to 200°C, more preferably 50 to 180°C, and even more preferably 60 to 170°C. The drying and curing time can be an appropriate and suitable time, for example, 5 seconds to 20 minutes, preferably 5 seconds to 10 minutes, more preferably 10 seconds to 5 minutes.

Examples of the above-mentioned active energy rays include ionizing radiation such as α-rays, β-rays, γ-rays, neutron rays, and electron beams, and ultraviolet rays. Ultraviolet rays through which the pressure-sensitive adhesive layer A exhibits transparency are particularly preferable. That is, the pressure-sensitive adhesive layer A has high light-shielding properties for visible light and high transmittance for ultraviolet rays, so that the base polymer can be cured by ultraviolet rays. In addition, the irradiation energy, irradiation time, and irradiation method of active energy rays are not particularly limited, and may be appropriately set so as to obtain desired viscosity and viscoelasticity according to the thickness of the adhesive layer A and the like.

For the main surface of the adhesive layer formed above that does not face the support, when the adhesive layer is photocured by the above-mentioned active energy rays and/or ultraviolet irradiation described later, in order to block the Oxygen is preferably further laminated with another support (including a release sheet).

Moreover, as another preferable 2nd Embodiment of the formation method of the said pressure-sensitive adhesive layer A, the method containing the following process is mentioned.

(1) An adhesive layer forming a single layer formed of the aforementioned base polymer.

(2) The aforementioned adhesive layer is cured.

(3) A solution of the aforementioned crosslinking agent and/or the aforementioned photopolymerization initiator is prepared.

(4) Apply the aforementioned solution on one side of the aforementioned cured adhesive layer, and make the aforementioned crosslinking agent and/or the aforementioned photopolymerization initiator contained in the solution extend along the thickness from the aforementioned one side of the aforementioned adhesive layer. directional penetration.

(5) The aforementioned pressure-sensitive adhesive layer is dried.

By forming the pressure-sensitive adhesive layer A according to the above-mentioned second embodiment, the curing reaction by the crosslinking agent and the polymerization initiator constituting the first initiator can be combined with the curing reaction by the crosslinking agent and the photopolymerization initiator constituting the second initiator. The curing reaction is separated, so it is no longer necessary to select the curing reaction conditions based on the curing of the crosslinking agent and polymerization initiator constituting the first initiator, the crosslinking agent constituting the first initiator, the polymerization initiator and the The degree of freedom in the combination of the cross-linking agent and the polymerization initiator of the compound is significantly improved.

In addition, by separating the curing reaction based on the crosslinking agent and the polymerization initiator constituting the first initiator from the curing reaction based on the crosslinking agent and the photopolymerization initiator constituting the second initiator, the curing reaction of the first initiator It is easy to adjust the absorbency of the obtained base polymer and the processability of the base polymer cured by the second initiator, and the pressure-sensitive adhesive layer A having both excellent absorbency of height difference and processability Ease of designing the photocurable pressure-sensitive adhesive sheet A and the degree of freedom are also remarkably improved.

FIG. 2 is a diagram (cross-sectional view) schematically showing a process for implementing a second embodiment of the method for producing the photocurable adhesive sheet A. FIG.

In (a) of FIG. 2 , first, an adhesive layer 10 a made of a base polymer is formed on the support body S1 .

In the pressure-sensitive adhesive layer forming step, first, the base polymer in which the crosslinking agent constituting the second initiator and the photopolymerization initiator are not compounded is applied (coated) on the support body S1. As the support body, the same support body as that of the first embodiment can be used.

Coating (coating) of the above-mentioned base polymer can be performed by a known coating method, for example, a gravure roll coater, reverse roll coater, lap coater, dip roll coater, rod coater, knife coater, etc. Cloth machine, spraying machine, comma coater, direct coater and other coating machines.

For the main surface of the adhesive layer 10a formed above that does not face the support S1, the adhesive layer is photocured by active energy rays and/or ultraviolet radiation described later in the adhesive layer curing step described later. In the case of , in order to block oxygen that inhibits photocuring, it is preferable to further laminate with another support S2 (including a release sheet).

Next, this adhesive layer 10a is cured (adhesive layer curing step). In (b) of FIG. 2, 10b is an adhesive layer obtained by hardening the adhesive layer 10a. Although it does not specifically limit as a method of hardening the adhesive layer 10a, For example, heating the adhesive layer 10a, irradiating the adhesive layer 10a with an active energy ray, and hardening it are mentioned. If necessary, heating and drying may be further performed. The specific curing conditions are the same as those in the first embodiment described above.

It should be noted that the drying curing, active energy ray irradiation, and heating drying in the above-mentioned adhesive layer curing step do not contain a crosslinking agent or a photopolymerization initiator constituting the second initiator. Any conditions can be used for the curing of the crosslinking agent of the 1 initiator and the polymerization initiator, and the degree of freedom is very high compared with the first embodiment.

Conditions for curing the pressure-sensitive adhesive layer 10a can be appropriately selected according to the embodiment so that the pressure-sensitive adhesive layer 10b has desired physical properties. For example, the heating temperature, time, or irradiation dose of active energy rays may be appropriately set so that the pressure-sensitive adhesive layer 10b exhibits high fluidity and excellent height difference absorption.

(b) of FIG. 2 is an embodiment in which the adhesive layer 10a is irradiated with ultraviolet rays U to cure the adhesive layer 10a. The pressure-sensitive adhesive layer 10 a constituting the pressure-sensitive adhesive layer A has high light-shielding properties for visible light and high transmittance for ultraviolet rays, and thus can be cured by ultraviolet rays U.

The ultraviolet rays U may be directly irradiated to the pressure-sensitive adhesive layer 10a, but it is preferable to irradiate through a support in order to block oxygen that inhibits curing by ultraviolet irradiation. (b) of FIG. 2 is embodiment which irradiates the adhesive layer 10a with ultraviolet rays through the support body S2. When irradiating ultraviolet rays through a support body, another support body S2 (including a release sheet) is bonded to the main surface of the adhesive layer 10a opposite to the main surface facing the support body S1, and ultraviolet rays are irradiated through the support body. . The illuminance and time of ultraviolet irradiation are appropriately set according to the composition of the base polymer, the thickness of the adhesive layer, and the like. For ultraviolet irradiation, a high-pressure mercury lamp, a low-pressure mercury lamp, a microwave excitation type lamp, a metal halide lamp, a chemical lamp, a black light lamp, an LED, or the like can be used.

Next, as shown in (c) of FIG. 2 , after the support S2 is peeled off and removed, one side of the adhesive layer 10 b is coated with a solution 14 of a crosslinking agent 11 and/or a photopolymerization initiator 12 (solution coating process). Here, the crosslinking agent 11 and the photopolymerization initiator 12 are a crosslinking agent and a photopolymerization initiator constituting the second initiator.

The solution 14 may contain a solvent, and when the crosslinking agent 11 functions as a solvent, it may not contain a solvent. (c) of FIG. 2 is an embodiment in which the solution 14 is a solution obtained by dissolving the crosslinking agent 11 and/or the photopolymerization initiator 12 in the solvent 13 .

The solvent 13 is not particularly limited as long as it can dissolve the aforementioned crosslinking agent 11 and/or photopolymerization initiator 12 and can swell the adhesive layer 10b. However, aqueous solvents have poor wettability to the adhesive layer, and additives are difficult to Osmotic, so non-aqueous solvents are preferred. The nonaqueous solvent is not particularly limited, and examples thereof include esters such as methyl acetate, ethyl acetate, isopropyl acetate, and butyl acetate; aromatic hydrocarbons such as toluene, xylene, and ethylbenzene; acetone, methyl ethyl ketone, Ketones such as methyl isobutyl ketone; alicyclic ketones such as cyclopentanone and cyclohexanone; aliphatic hydrocarbons such as hexane, heptane and octane; alicyclic hydrocarbons such as cyclohexane; chloroform, methylene chloride, Halogenated hydrocarbons such as 1,2-dichloroethane; ethers such as diethyl ether, dimethoxyethane, tetrahydrofuran, dioxane, etc.; N,N-dimethylformamide, N,N- Amides such as dimethylacetamide; Nitriles such as acetonitrile, propionitrile, and benzonitrile; Alcohols such as methanol, ethanol, propanol, isopropanol, n-butanol, isobutanol, sec-butanol, and tert-butanol, preferably Esters, aromatic hydrocarbons, ketones, alcohols. A solvent may be used individually by 1 type, and may use it in combination of 2 or more types.

The concentration of the above-mentioned crosslinking agent 11 and/or photopolymerization initiator 12 in the solution 14 can be appropriately set, for example, it can be from 0.1 to 100% by weight, preferably 0.1 to 80% by weight, more preferably 1 to 70% by weight, More preferably, it is selected in the range of 1.5 to 60 weight%, more preferably 3 to 50 weight%, and still more preferably 5 to 40 weight%. When the concentration of the crosslinking agent 11 and/or the photopolymerization initiator 12 in the solution 14 is within this range, the crosslinking agent 11 and/or the photopolymerization initiator 12 can be dissolved to sufficiently swell the pressure-sensitive adhesive layer 10b.

The concentration of the crosslinking agent 11 in the solution 14 can be appropriately set, for example, it can be from 0.1 to 100% by weight, such as 95% by weight or less (such as 1 to 95% by weight, 1 to 90% by weight, 1 to 85% by weight, 1 to 80% by weight, 1 to 60% by weight, etc.), for example, 1% by weight or more (for example, 1 to 95% by weight, 2 to 95% by weight). When the concentration of the cross-linking agent is higher than the above-mentioned range, the cross-linking agent 11 may ooze out, or distribution deviation may occur from the viewpoint of coating uniformity. In addition, when the concentration is thinner than the above range, the solvent needs to exceed the requirement, and the adhesive properties may be reduced due to the residual solvent, and defects in appearance (called surface unevenness) due to swelling of the adhesive beyond the requirement may occur. .

Coating (coating) of the above-mentioned solution 14 on the adhesive layer 10b can be performed using a known coating method, for example, a gravure roll coater, a reverse roll coater, a lip coater, a dip roll coater, a rod coater, etc. Coater, blade coater, spray coater, comma coater, direct coater and other coating machines.

The coating amount of the solution 14 on the adhesive layer 10b can be appropriately set, for example, it can be from 1 to 1000 μg/cm ² , preferably 1 to 500 μg/cm ² , more preferably 1 to 300 μg/cm ² , and even more preferably 1 Select from the range of ~100μg/cm ² . If the application amount of the solution 14 is within this range, the crosslinking agent 11 and/or the photoinitiator 12 can be dissolved and the crosslinking agent 11 and/or the photoinitiator 12 can be fully provided to the adhesive layer 10b.

After the solution 14 is applied to the pressure-sensitive adhesive layer 10b, the crosslinking agent 11 and/or the photopolymerization initiator 12 may be permeated by standing as necessary. The standing time is not particularly limited, and can be appropriately selected, for example, within 15 minutes, and can be selected from, for example, 1 second to 10 minutes, preferably 5 seconds to 5 minutes. As the standing temperature, it can be performed at room temperature (about 10 to 30°C). When left still under the above-mentioned conditions, the crosslinking agent 11 and/or the photopolymerization initiator 12 can be fully permeated in the adhesive layer 10b.

The surface of the adhesive layer 10b is infiltrated with the solution 14 to swell, and in this process, the crosslinking agent 11 and/or the photopolymerization initiator 12 in the solution 14 penetrates in the thickness direction in the adhesive layer 10b (solution infiltration process) . This state is shown in (d) of FIG. 2 . The crosslinking agent 11 and/or the photopolymerization initiator 12 penetrate into the adhesive layer 10b in a dissolved state. Therefore, the crosslinking agent 11 and/or the photoinitiator 12 will be in the state of "dissolving" in the adhesive layer 10b.

In addition, the crosslinking agent 11 and/or the photopolymerization initiator 12 can form a concentration gradient in the thickness direction during penetration into the pressure-sensitive adhesive layer 10b. Therefore, the concentration of the crosslinking agent 11 and/or the photopolymerization initiator 12 may be higher on the face side coated with the solution 14 than on the opposite face side. This state is shown in (d) of FIG. 2 .

Then, by drying the adhesive layer 10b, the adhesive layer 10 shown in FIG.2(e) can be obtained (drying process). When the solution 14 contains the solvent 13, the solvent 13 evaporates by the drying process. Through the drying process, the pressure-sensitive adhesive layer 10b returns to a state similar to that before swelling. At the point in time when the adhesive layer 10b is dried, the penetration of the crosslinking agent 11 and/or photopolymerization initiator 12 to the adhesive layer 10b stops, and the concentration gradient of the aforementioned crosslinking agent 11 and/or photopolymerization initiator 12 be fixed.

The heat drying temperature in the drying step is preferably 40 to 200°C, more preferably 50 to 180°C, and even more preferably 60 to 170°C. An appropriate and suitable time can be adopted for the drying time, for example, 5 seconds to 20 minutes, preferably 5 seconds to 10 minutes, more preferably 10 seconds to 5 minutes. By drying under the above conditions, the pressure-sensitive adhesive layer 10 can return to a state close to that before coating.

In addition, the standing time for further homogenizing the crosslinking agent and the adhesive layer can be set as needed. The standing time is not particularly limited, and can be appropriately selected, for example, within 30 days, for example, between 1 hour and 15 days, preferably between 24 hours and 10 days. By standing still, the crosslinking agent and the pressure-sensitive adhesive layer of the pressure-sensitive adhesive layer 10 are stabilized, and variations in property evaluation can be suppressed.

The photocurable adhesive sheet 1B shown in FIG. 2( e ) is one embodiment of the photocurable adhesive sheet A including an adhesive layer 10 made of a base polymer, A mixed adhesive composition of a crosslinking agent 11 and a photopolymerization initiator 12 is formed.

In the aforementioned second embodiment, the base polymer includes the first crosslinking agent and the first polymerization initiator as the first initiator, and the aforementioned pressure-sensitive adhesive layer curing step is based on the first crosslinking agent and the first polymerization initiator. In the curing of the reaction, the crosslinking agent 11 and the photopolymerization initiator 12 become the second initiator.

After the pressure-sensitive adhesive layer curing step, both or either of the first crosslinking agent and the first polymerization initiator may remain. In this case, only one of the second crosslinking agent and the second polymerization initiator may be used as the crosslinking agent 11 and the photopolymerization initiator 12, and it is preferable to use only the second crosslinking agent (crosslinking agent 11). However, both the second crosslinking agent and the second polymerization initiator may be used.

In the above-mentioned second embodiment, the degree of freedom in combination of the first initiator and the second initiator is very wide. That is, the combination of polymerization initiators is not limited, for example, a combination in which both the first initiator and the second initiator are photopolymerization initiators, the first initiator is a thermal polymerization initiator and the second initiator is a photopolymerization initiator can be freely selected. combination of initiators, etc. In addition, when both the first initiator and the second initiator are a combination of photopolymerization initiators, the light absorption wavelength bands of the two photopolymerization initiators may overlap or approximate each other. Furthermore, there may be a combination in which the same polymerization initiator is used as the first initiator and the second initiator, which is impossible for conventional hybrid adhesive sheets.

In addition, the combination of crosslinking agents is not limited either, and a combination of the same crosslinking agent as the first initiator and the second initiator is also possible.

Fig. 3(a) is a sectional view showing one embodiment of the photocurable adhesive sheet A of the present invention, and Fig. 3(b) is a cross-sectional view showing another embodiment of the photocurable adhesive sheet A of the present invention Sectional view of the way.

Referring to (a) of FIG. 3 , a photocurable adhesive sheet 1C according to an embodiment of the present invention is composed of an adhesive layer 10 and a support S1, and one surface of the adhesive layer 10, that is, the first main surface 10A A support body is bonded, and the said support body S1 is formed with the release sheet bonded to the 2nd main surface 10B which is the other surface of this adhesive layer 10.

Referring to (b) of FIG. 3 , the photocurable adhesive sheet 1D according to one embodiment of the present invention is peeled from the adhesive layer 10 and the first main surface 10A, which is one surface bonded to the adhesive layer 10 . The first support body S2 formed of a sheet, and the second support body S1 formed of a release sheet bonded to the second main surface 10B, which is the other surface of the pressure-sensitive adhesive layer 10 , are constituted. Photocurable adhesive sheet 1D can be obtained by bonding support body S2 to 10 A of 1st main surfaces of 1 C of photocurable adhesive sheets.

In (a) and (b) of FIG. 3 , the dotted line XX' is a line that divides the adhesive layer 10 into two equally in the thickness direction. When the thickness of the pressure-sensitive adhesive layer 10 is not uniform, the dotted line XX' is a line which halved the thickness of each point.

In FIG. 3 , the pressure-sensitive adhesive layer 10 is a single layer formed of a base polymer and having two opposing main surfaces (a first main surface and a second main surface). The pressure-sensitive adhesive layer 10 can be formed by the method of the aforementioned second embodiment, and corresponds to the pressure-sensitive adhesive layer 10 of FIG. 2 .

The "single layer" of the adhesive layer means that it is not a laminated structure. For example, a structure in which an adhesive layer made of a base polymer is formed and an adhesive layer made of the same base polymer is further formed thereon is a laminated structure, not a single layer. Similarly, an adhesive layer composed of a base polymer containing a crosslinking agent and/or a photopolymerization initiator is formed, and further formed thereon with a crosslinking agent and/or a photopolymerization initiator dissolved in different concentrations. The structure of the adhesive layer formed by the base polymer is a laminated structure, not a single layer.

The thickness of the pressure-sensitive adhesive layer 10 is not particularly limited, but is usually 5 μm to 500 μm, preferably 5 μm to 400 μm, more preferably 5 μm to 350 μm. When the thickness of the adhesive layer 10 exists in this range, it is suitable for forming the concentration gradient of a crosslinking agent and/or a photoinitiator in the thickness direction of the adhesive layer 10.

Regarding the crosslinking agent 11 and/or the photopolymerization initiator 12, the crosslinking agent 11 and/or the photopolymerization initiator 12 are permeated into the adhesive layer 10 through the aforementioned solution application process, solution penetration process, and drying process, thereby Forming, as shown in FIG. 3 , a concentration gradient of the crosslinking agent 11 and/or the photopolymerization initiator 12 may be generated in the thickness direction of the adhesive layer 10 . Therefore, when the single-layer adhesive layer 10 is equally divided into two in the thickness direction, the crosslinking agent 11 and/or light in the area where one of the two main surfaces, that is, the first main surface 10A belongs, The concentration of the polymerization initiator 12 is different from the concentration of the crosslinking agent 11 and/or the photopolymerization initiator 12 in the region to which the second main surface 10B belongs. The case where the crosslinking agent 11 and/or the photopolymerization initiator 12 does not exist in the area where the concentration is low (the concentration is 0) is also included in the scope of the present invention.

When the above-mentioned concentration of the region to which the first main surface belongs and the aforementioned concentration of the region to which the second main surface belongs also have concentration gradients in the respective regions, it means that the crosslinking agent 11 and/or photopolymerization initiation in the respective regions The average concentration of agent 12.

(a) of FIG. 3 shows an embodiment in which the aforementioned second main surface 10B faces the aforementioned crosslinking agent 11 and/or photopolymerization initiator 12 in the area to which the aforementioned first main surface 10A belongs on the aforementioned support body S1. The concentration is higher than the concentration of the aforementioned crosslinking agent 11 and/or photopolymerization initiator 12 in the area to which the aforementioned second main surface 10B belongs, and can be obtained by applying the crosslinking agent 11 and/or photopolymerization initiator 12 on the aforementioned first main surface 10A. In the solution of/or the photopolymerization initiator 12, the crosslinking agent 11 and/or the photopolymerization initiator 12 penetrate into the pressure-sensitive adhesive layer 10 from the first main surface 10A to the entire depth in the thickness direction in a dissolved state.

The adhesive layer 10 has a concentration gradient of the crosslinking agent 11 and/or photopolymerization initiator 12 in the thickness direction, and as a result, when the adhesive layer 10 is cured, the crosslinking density can be different between the surface and the back surface. That is, in FIG. 3 , the region to which the main surface 10A belongs can generate a higher crosslink density than the region to which the main surface 10B belongs. This configuration is preferable in that the flexibility can be improved, for example, when the photocurable pressure-sensitive adhesive sheet A is used as a flexible image display device in which one side of the main surface 10A is bent outward. That is, when a flexible display is bent, generally tensile stress is applied to the outside and compressive stress is applied to the inside, and the outside stress is stronger than the inside stress. Therefore, by arranging the main surface 10A of the adhesive layer 10 on the outside when the flexible display is bent, durability against bending can be improved.

Another third embodiment of the mixed adhesive composition constituting the adhesive layer A includes a polymer having a benzophenone structure in a side chain (hereinafter sometimes referred to as "BP polymer"). Adhesive composition (hereinafter sometimes referred to as "BP-type hybrid adhesive composition"). The "benzophenone structure" functions as the second initiator in the hybrid adhesive.

As a suitable example of a BP polymer, an acrylic polymer which has a benzophenone structure in a side chain is mentioned. It is preferable that the said BP polymer is a polymer which does not contain an ethylenically unsaturated group substantially.

In this specification, "benzophenone structure" refers to a diaryl ketone represented by the general formula: Ar ¹ -(C=O)-Ar ² -; or -Ar ³ -(C=O)-Ar ² - structure. Here, Ar ¹ in the above general formula is selected from phenyl groups optionally having substituents. Ar ² and Ar ³ in the above general formula are each independently selected from phenylene groups which may have substituents. Ar ² and Ar ³ may be the same or different. The benzophenone structure can be excited by ultraviolet irradiation, and in this excited state, hydrogen radicals can be abstracted from other molecules or other parts of the molecule.

The adhesive layer formed from the aforementioned BP-type hybrid adhesive composition contains a polymer (BP polymer) having a benzophenone structure in a side chain, so that the above-mentioned hydrogen can be utilized by exciting the benzophenone structure. The capture reaction of free radicals forms a cross-linked structure. As the above-mentioned polymer having a benzophenone structure in the side chain, the above-mentioned general formula: Ar ¹ -(C=O)-Ar ² - in which Ar ¹ is a phenyl group optionally having a substituent, and Ar ² is preferably A polymer having a benzophenone structure in a side chain of a phenylene group optionally having a substituent. When at least one of the above-mentioned Ar ¹ and Ar ² has one or more substituents, the substituents may be independently selected from alkoxy groups (for example, alkoxy groups having 1 to 3 carbon atoms. Preferably methoxy groups) , a group consisting of a halogen atom (such as F, Cl, Br, etc., preferably Cl or Br), a hydroxyl group, an amino group and a carboxyl group.

The aforementioned BP polymer may have a side chain directly bonded to the main chain with the above-mentioned benzophenone structure, or may have a side chain bonded to the main chain by means of one or more of such as an ester bond, an oxyalkylene structure, etc. Bonded side chains. Examples of suitable BP polymers include those containing repeating units derived from compounds having an ethylenically unsaturated group and a benzophenone structure in the molecule (hereinafter sometimes referred to as "ethylenically unsaturated BP"). polymer. The above-mentioned repeating unit may be a polymeric residue obtained by reacting the ethylenically unsaturated group of the corresponding ethylenically unsaturated BP.

Examples of the aforementioned ethylenically unsaturated BP include: 4-acryloyloxybenzophenone, 4-acryloyloxy-4'-methoxybenzophenone, 4-acryloyloxyethoxy Base-4'-methoxybenzophenone, 4-acryloyloxy-4'-bromobenzophenone, 2-hydroxy-4-acryloyloxybenzophenone, etc. optionally have substituents Acryloyloxybenzophenone; 4-[(2-acryloyloxy)ethoxy]benzophenone, 4-[(2-acryloyloxy)ethoxy]-4'-bromodiphenone Acryloyloxyalkoxybenzophenone optionally with substituents such as benzophenone; 4-methacryloyloxybenzophenone, 4-methacryloyloxy-4'-methoxy Benzophenone, 4-methacryloxy-4'-bromobenzophenone, 4-methacryloxyethoxy-4'-bromobenzophenone, 2-hydroxy-4- Methacryloyloxybenzophenone and other optionally substituted methacryloyloxybenzophenone; 4-[(2-methacryloyloxy)ethoxy]benzophenone, 4-[(2-methacryloyloxy)ethoxy]-4'-methoxybenzophenone and other methacryloyloxyalkoxybenzophenones optionally with substituents; 4 Vinyl benzophenone, 4'-bromo-3-vinyl benzophenone, 2-hydroxy 4-methoxy-4'-vinyl benzophenone, etc. Benzophenone etc., but not limited to these. Ethylenically unsaturated BP can be used alone or in combination of two or more for the preparation of BP polymers. A commercially available thing can be used for ethylenically unsaturated BP, and it can also synthesize|combine by a well-known method. Ethylenically unsaturated BP having a (meth)acryloyl group, that is, ethylenically unsaturated BP belonging to an acrylic monomer can be preferably used from the viewpoint of reactivity and the like.

The aforementioned BP polymer may have repeating units derived from ethylenically unsaturated BP and repeating units derived from ethylenically unsaturated compounds not belonging to ethylenically unsaturated BP (hereinafter also referred to as "other ethylenically unsaturated compounds") of copolymers. Such a BP polymer may be a copolymer comprising monomer components of the above-mentioned ethylenically unsaturated BP and the above-mentioned other ethylenically unsaturated compounds. In addition, the aforementioned BP polymer may be a copolymer obtained by copolymerizing only a partial polymer (prepolymer) of a monomer mixture composed of the aforementioned other ethylenically unsaturated compound and the aforementioned ethylenically unsaturated BP. As the above-mentioned other ethylenically unsaturated compounds, one or two or more acrylic monomers can be preferably used. Suitable examples of BP polymers include acrylic monomers in which more than 50% by weight (preferably more than 70% by weight, for example, more than 90% by weight) of the monomer components constituting the BP polymer are acrylic monomers. BP polymer.

As the acrylic monomer as the above-mentioned other ethylenically unsaturated compound, the same monomer as the alkyl acrylate having a linear or branched alkyl group constituting the monomer unit of the above-mentioned acrylic polymer can be used. The monomer components constituting the BP polymer may also comprise one or more of alicyclic monomers, hydroxyl-containing monomers, nitrogen-atom-containing monomers, and carboxyl-containing monomers selected from the monomer units constituting the above-mentioned acrylic polymers. Two or more kinds are used as the above-mentioned other ethylenically unsaturated compounds.

The aforementioned BP-type hybrid adhesive composition may be a photocurable acrylic monomer in which more than 50% by weight (preferably higher than 70% by weight, such as higher than 90% by weight) of the total monomer components constituted are acrylic monomers. Adhesive composition. The photocurable acrylic pressure-sensitive adhesive composition forms a photocured acrylic product by photocuring.

The weight-average molecular weight (Mw) of the BP polymer is not particularly limited, and may be, for example, about 0.5×10 ⁴ to 500×10 ⁴ . From the viewpoint of the cohesiveness of the adhesive layer A and the handleability of the photocurable adhesive sheet A, the Mw of the above-mentioned BP polymer is generally 1×10 ⁴ or more, preferably 5×10 ⁴ or more, It may be 10×10 ⁴ or more, 15×10 ⁴ or more, or 20×10 ⁴ or more. In addition, from the viewpoint of the level difference absorbability of the pressure-sensitive adhesive layer A, the Mw of the BP polymer is generally 200×10 ⁴ or less, preferably 150×10 ⁴ or less, may be 100×10 ⁴ or less, may be It is 70×10 ⁴ or less, and may be 50×10 ⁴ or less.

In addition, the weight average molecular weight (Mw) of a polymer means the value in terms of standard polystyrene obtained by gel permeation chromatography (GPC). As the GPC apparatus, for example, a model name "HLC-8320GPC" (column: TSKgelGMH-H(S), manufactured by Tosoh Corporation) can be used.

The glass transition temperature (Tg) of the aforementioned BP polymer is not particularly limited. The Tg of the BP polymer may be, for example, -80°C to 150°C, -80°C to 50°C, or -80°C to 10°C. From the viewpoint of the level difference absorbability of the pressure-sensitive adhesive layer A, the Tg of the BP polymer is suitably lower than 0°C, preferably -10°C or lower, may be -20°C or lower, may be -30°C or lower, may be It is -40°C or lower, and may be -50°C or lower. In addition, from the viewpoint of improving the cohesiveness of the pressure-sensitive adhesive layer A and the processability after photocuring, it is generally advantageous that the Tg of the BP polymer be -75°C or higher, and may be -70°C or higher. In some embodiments, the Tg of the BP polymer may be -55°C or higher, or -45°C or higher. The Tg of the BP polymer can be adjusted by the type and amount of monomer components constituting the BP polymer.

Here, the glass transition temperature (Tg) of a polymer refers to the glass transition temperature obtained by Fox's formula based on the composition of monomer components constituting the polymer. The above-mentioned Fox formula is a relational expression of the Tg of a copolymer and the glass transition temperature Tgi of the homopolymer obtained by homopolymerizing each monomer which comprises this copolymer, as shown below.

1/Tg＝Σ(Wi/Tgi)

It should be noted that, in the above-mentioned Fox formula, Tg represents the glass transition temperature (unit: K) of the copolymer, Wi represents the weight fraction of the monomer i in the copolymer (copolymerization ratio on a weight basis), and Tgi represents the monomer i. The glass transition temperature (unit: K) of the homopolymer of i.

As the glass transition temperature of the homopolymer used in the calculation of Tg, a value described in a known document is used. For example, for the monomers listed below, the following values are used as the glass transition temperature of the homopolymer of the monomer.

2-ethylhexyl acrylate: -70°C

n-Butyl Acrylate: -55°C

Isostearyl acrylate: -18°C

Methyl methacrylate: 105°C

Methyl acrylate: 8°C

Cyclohexyl acrylate: 15°C

N-vinyl-2-pyrrolidone: 54°C

2-Hydroxyethyl acrylate: -15°C

4-Hydroxybutyl acrylate: -40°C

Isobornyl Acrylate: 94°C

Acrylic acid: 106°C

Methacrylic acid: 228°C

For the glass transition temperature of homopolymers of monomers other than those listed above, values described in "Polymer Handbook" (3rd edition, John Wiley & Sons, Inc., 1989) are used. When multiple values are described in this document, the highest value is adopted. The value obtained by the measurement method described in JP-A-2007-51271 was used for monomers whose glass transition temperatures of homopolymers are not described in the above-mentioned Polymer Handbook. In addition, the nominal value of a glass transition temperature can also be used for the polymer which the manufacturer etc. provided the nominal value of a glass transition temperature.

The BP polymer preferably contains, for example, about 0.5 mg or more of a benzophenone structure in terms of 4-benzoylphenyl acrylate per 1 g of the polymer. Hereinafter, the value obtained by converting the number of benzophenone structures contained in 1 g of BP polymer into the equivalent amount of 4-benzoylphenyl acrylate may be referred to as the BP equivalent of BP polymer (unit: mg/g) . For example, when 40 μmol of benzophenone structures are contained per 1 g, the BP equivalent of the polymer is calculated to be 10 mg/g.

From the viewpoint of obtaining a higher photocuring effect (for example, the effect of improving processability by photocuring), in some embodiments, it is appropriate for the BP equivalent of the BP polymer to be 0.11 mg/g or more, and may be 0.5 mg/g or more, may be 1 mg/g or more, may be 5 mg/g or more, may be 8 mg/g or more, may be 10 mg/g or more, may be 15 mg/g or more, or may be 20 mg/g or more. In addition, in some embodiments, from the viewpoint of improving the impact resistance and peel strength of the junction based on the photocured product, the BP equivalent of the BP polymer is generally 100 mg/g or less, and may be 80 mg/g or less. It may be 60 mg/g or less, 40 mg/g or less, 25 mg/g or less, or 15 mg/g or less. The BP equivalent of a BP polymer can be adjusted by the composition of the monomer component which comprises this BP polymer.

In addition, from the viewpoint of reducing the peeling force by photocuring, reprocessing, and maintenance, the BP equivalent is preferably 50 mg/g or more, and may be 100 mg/g or more.

The weight ratio of the BP polymer in the whole of the BP-type hybrid adhesive composition, that is, the weight fraction of the BP polymer in the BP-type hybrid adhesive composition is not particularly limited, and can be based on the height of the adhesive layer A The poor absorption property and the workability of the photocured product are set in a proper balance. In some embodiments, the weight fraction of the above-mentioned BP polymer may be, for example, 1% by weight or more, usually 5% by weight or more is appropriate, may be 10% by weight or more, may be 15% by weight or more, and may be 25% by weight or more , may be 35% by weight or more, may be 45% by weight or more, or may be 55% by weight or more. When the weight fraction of the BP polymer increases, the aforementioned G'a10/G'b85 tends to increase.

It may also be carried out so that the weight fraction of the BP polymer in the BP-type hybrid adhesive composition is substantially 100% by weight (for example, 99.5% by weight or more). In addition, from the viewpoint of the ease of adhesive performance, in some embodiments, the weight fraction of the BP polymer in the BP-type hybrid adhesive composition may be lower than 99% by weight, lower than 95% by weight, or lower than 95% by weight. It may be less than 85% by weight, may be less than 70% by weight, may be less than 50% by weight, or may be less than 40% by weight.

In terms of 4-benzoylphenyl acrylate, it is preferable to contain, for example, about 0.1 mg or more of the benzophenone structure per 1 g of the BP-type hybrid adhesive composition. Hereinafter, the weight in terms of 4-benzoylphenyl acrylate of the benzophenone structure contained per 1 g of the BP-type hybrid binder composition may be referred to as the BP equivalent of the BP-type hybrid binder composition (unit : mg/g). From the viewpoint of obtaining a higher photocuring effect (for example, the effect of improving processability by photocuring), in some embodiments, it is appropriate that the BP equivalent of the BP-type hybrid adhesive composition is generally 0.3 mg/g or more , may be 0.5 mg/g or more, may be 1 mg/g or more, may be 5 mg/g or more, may be 10 mg/g or more, and may be 20 mg/g or more. In addition, in some embodiments, the BP equivalent of the BP-type hybrid adhesive composition is usually 100 mg/g or less from the viewpoint of the impact resistance of the joint portion based on the photo-cured product and suppression of strain in the photo-cured product. Suitably, it may be 80 mg/g or less, 60 mg/g or less, 40 mg/g or less, 25 mg/g or less, or 15 mg/g or less.

The aforementioned BP-type hybrid adhesive composition may be an adhesive composition comprising an ethylenically unsaturated compound and a BP polymer. The aforementioned BP-type mixed adhesive composition may be higher than 50% by weight (preferably higher than 70% by weight, for example higher than 90% by weight) of the total monomer components constituting the adhesive composition is an acrylic monomer acrylic adhesive composition.

As the above-mentioned ethylenically unsaturated compound, alkyl acrylates, alicyclic monomers, hydroxyl-containing monomers, alicyclic monomers, hydroxyl-containing monomers, Compounds similar to nitrogen atom-containing monomers, carboxyl group-containing monomers, and polyfunctional (meth)acrylates.

The ethylenically unsaturated compound may contain an alkyl acrylate in a ratio of 40% by weight or more. The ratio of the alkyl acrylate to the monomer components may be, for example, 50% by weight or more, 60% by weight or more, or 65% by weight or more. In addition, from the viewpoint of improving the cohesion of the pressure-sensitive adhesive layer A, the ratio of the alkyl acrylate to the ethylenically unsaturated compound is generally 99.5% by weight or less. It may be 95% by weight or less. It may be 85 weight% or less, may be 70 weight% or less, and may be 60 weight% or less.

The usage-amount when using an alicyclic monomer is not specifically limited, For example, it can be 1 weight% or more, 3 weight% or more, or 5 weight% or more of all monomer components. In one embodiment, the usage-amount of an alicyclic monomer may be 10 weight% or more of all monomer components, and may be 15 weight% or more. The upper limit of the usage amount of the alicyclic monomer is preferably about 40% by weight or less, for example, 30% by weight or less, or 25% by weight or less (for example, 15% by weight or less, further 10% by weight or less). Alternatively, an alicyclic monomer may not be used as the above-mentioned ethylenically unsaturated compound.

The usage amount when using a nitrogen atom-containing monomer is not particularly limited, for example, it may be 1% by weight or more, 2% by weight or more, 3% by weight or more, and furthermore, 5% by weight or more or 7% by weight of the total monomer components. % by weight or more. In one embodiment, the used amount of the nitrogen atom-containing monomer may be 10% by weight or more, 15% by weight or more, or 20% by weight or more of the total monomer components. In addition, the usage-amount of the monomer containing a nitrogen atom is suitably set to 40 weight% or less of the whole monomer component, for example, may be 35 weight% or less, may be 30 weight% or less, and may be 25 weight% or less. the following. In another embodiment, the amount of the nitrogen atom-containing monomer used may be, for example, 20% by weight or less, or 15% by weight or less of the total monomer components. Alternatively, a nitrogen atom-containing monomer may not be used as the above-mentioned ethylenically unsaturated compound.

The usage amount when using a hydroxyl group-containing monomer is not particularly limited, for example, it may be 0.01% by weight or more, 0.1% by weight or more, 0.5% by weight or more, 1% by weight or more, or 5% by weight or more or 10% by weight or more. In addition, from the viewpoint of suppressing water absorption of the BP-type hybrid adhesive composition or the adhesive layer A, in some embodiments, the usage amount of the hydroxyl group-containing monomer is, for example, 40% by weight or less of the total monomer components. Suitably, it may be 30 weight% or less, may be 25 weight% or less, and may be 20 weight% or less. In another embodiment, the amount of the hydroxyl group-containing monomer used may be, for example, 15% by weight or less, 10% by weight or less, or 5% by weight or less of the total monomer components. Alternatively, a hydroxyl group-containing monomer may not be used as the above-mentioned ethylenically unsaturated compound.

The usage amount when using the carboxyl group-containing monomer is not particularly limited, and the ratio in the total monomer components can be, for example, 2% by weight or less, 1% by weight or less, or 0.5% by weight or less (for example, less than 0.1% by weight). weight). The BP-type hybrid adhesive composition may not substantially contain a carboxyl group-containing monomer as its constituent monomer component. Here, substantially not containing a carboxyl group-containing monomer means that at least a carboxyl group-containing monomer is not used intentionally. This may be advantageous from the viewpoint of the metal corrosion prevention properties of the adhesive layer A formed from the BP-type hybrid adhesive composition and its photocured product.

The usage-amount when using polyfunctionality (meth)acrylate is not specifically limited, It can be made into less than 5.0 weight% of all the monomer components which comprise BP type hybrid adhesive composition. Thereby, formation of an excessive crosslinked structure can be avoided at the time of formation of the adhesive layer A (that is, the stage before photocuring), and the level difference absorption property of the said adhesive layer A can be improved. The amount of the polyfunctional (meth)acrylate used may be, for example, 4.0% by weight or less, 3.0% by weight or less, 2.0% by weight or less, 1.0% by weight or less, or 0.5% by weight of the total monomer components. % by weight or less, may be 0.3% by weight or less. It is also possible not to use polyfunctional (meth)acrylate. In addition, in some embodiments, from the viewpoint of imparting moderate cohesion to the pressure-sensitive adhesive layer A, the usage amount of the polyfunctional (meth)acrylate relative to the total monomer components may be, for example, 0.001% by weight or more. , may be 0.005% by weight or more, may be 0.01% by weight or more, or may be 0.03% by weight or more. Alternatively, a polyfunctional (meth)acrylate may not be used as the above-mentioned ethylenically unsaturated compound.

The weight ratio of the BP polymer in the total amount of the BP polymer and the ethylenically unsaturated compound contained in the BP-type hybrid adhesive composition is not particularly limited, and the adhesive formed by the adhesive composition can be made The height difference absorption property of the mixture layer A is set so that the workability of its photocured product can be balanced suitably. In some embodiments, the weight fraction of the above-mentioned BP polymer can be, for example, more than 0.5% by weight, usually more than 1% by weight, preferably more than 1.5% by weight, more preferably more than 5% by weight. From the viewpoint of the effect, it may be 10% by weight or more, 15% by weight or more, 25% by weight or more, 35% by weight or more, 45% by weight or more, or 55% by weight or more. In addition, from the viewpoint of the ease of preparation and coating of the adhesive composition, in some embodiments, the weight ratio of the BP polymer in the above total amount can be lower than 99% by weight, lower than 95% by weight, less than 85% by weight, less than 70% by weight, less than 50% by weight, or less than 40% by weight.

The ratio of the weight of the organic solvent to the weight of the entire BP-type hybrid adhesive composition may be, for example, 30% by weight or less, preferably 20% by weight or less, preferably 10% by weight or less, more preferably 5% by weight or less. % by weight or less. In some embodiments, the weight ratio of the above-mentioned organic solvent may be 3% by weight or less, may be 1% by weight or less, may be 0.5% by weight or less, may be 0.1% by weight or less, may be 0.05% by weight or less, or may be substantially Does not contain organic solvents.

The viscosity of the BP-type mixed adhesive composition (BH-type viscometer, No. 5 spindle, 10 rpm, measurement temperature 30°C) was measured from the viewpoint of coatability in the normal temperature range. The same applies below. ) is suitably 1000 Pa·s or less, preferably 100 Pa·s or less, more preferably 50 Pa·s or less. The viscosity of the BP-type hybrid adhesive composition may be, for example, 30 Pa·s or less, 20 Pa·s or less, 10 Pa·s or less, or 5 Pa·s or less. The lower limit of the viscosity of the BP-type hybrid adhesive composition is not particularly limited, and from the viewpoint of suppressing shrinkage of the adhesive composition within the coating range and overflow of the adhesive composition at the outer edge of the coating range, Usually, 0.1 Pa·s or more is suitable, and it may be 0.5 Pa·s or more, and may be 1 Pa·s or more.

The BP-type hybrid adhesive composition may contain at least one ethylenically unsaturated group-containing compound (that is, a monofunctional monomer) as the above-mentioned ethylenically unsaturated compound. As the monofunctional monomer, a corresponding compound can be selected and used from the examples of the above-mentioned ethylenically unsaturated compound. A monofunctional monomer can be used individually by 1 type or in combination of 2 or more types.

The weight ratio of the monofunctional monomer in the total amount of the BP polymer and the ethylenically unsaturated compound may be, for example, 1% by weight or more, 5% by weight or more, or 15% by weight or more. In some embodiments, the weight ratio of the above-mentioned monofunctional monomer may be 25% by weight or more, 35% by weight or more, or It may be 45% by weight or more. In addition, in the above total amount, the weight ratio of the monofunctional monomer may be, for example, 99% by weight or less, usually 95% by weight or less is suitable, may be 85% by weight or less, may be 75% by weight or less, may be 65% by weight or less. % by weight or less may be 55% by weight or less, or may be 45% by weight or less.

In the form in which the BP-type hybrid adhesive composition contains a monofunctional monomer, the glass transition temperature (Tg) obtained using the Fox formula based on the composition of the monofunctional monomer is not particularly limited, and may be, for example, - Above 80°C and below 250°C. From the viewpoint of the compatibility of the polymer derived from the monofunctional monomer with other components, etc., the Tg based on the composition of the monofunctional monomer is usually preferably 150°C or lower, may be 100°C or lower, may be 70°C or less may be 50°C or less, or may be 30°C or less. In some embodiments, the Tg based on the composition of the monofunctional monomer is preferably lower than 0°C, more preferably -10°C or lower, and may be -20°C from the viewpoint of the level difference absorbability of the pressure-sensitive adhesive layer A. It may be -30°C or less, or -40°C or less. In addition, from the viewpoint of the cohesiveness of the pressure-sensitive adhesive layer A and the workability after photocuring, it is generally advantageous that the Tg based on the composition of the monofunctional monomer be -60°C or higher, and may be -54°C or higher, It may be -50°C or higher, -45°C or higher, -35°C or higher, or -25°C or higher. The above-mentioned Tg can be adjusted by the compounds used as monofunctional monomers and their usage ratio.

In the BP-type hybrid adhesive composition comprising a BP polymer and a monofunctional monomer, the adhesive layer A formed from the adhesive composition, and its photocured product, the Tg of the BP polymer (hereinafter referred to as "Tg _A ".) and the Tg of the monomer composition based on the monofunctional monomer (hereinafter referred to as "Tg _B1 ".) can be calculated by Tg _B1 [°C] - Tg _A [°C] Tg difference [°C ] (hereinafter also referred to as ΔTg.) is set so as to be, for example, in the range of -50°C or higher and 70°C or lower. From the viewpoint of the compatibility of the adhesive layer A with its photocured product, it may be advantageous that the absolute value of the above-mentioned Tg difference is not too large. In some embodiments, ΔTg may be -10°C or higher, preferably 0°C or higher, 7°C or higher, 10°C or higher, 20°C or higher, or 30°C or higher.

The BP-type hybrid adhesive composition may contain at least a compound having two or more ethylenically unsaturated groups (that is, a polyfunctional monomer) as the above-mentioned ethylenically unsaturated compound. The polyfunctional monomer can be used individually by 1 type or in combination of 2 or more types from the illustration of the said polyfunctional monomer. The usage-amount of a polyfunctional monomer can be set similarly to the ratio which a polyfunctional (meth)acrylate occupies to the whole monomer component which comprises an adhesive composition.

In an embodiment in which a monofunctional monomer and a polyfunctional monomer are used in combination as the ethylenically unsaturated compound, the weight ratio of the monofunctional monomer to the ethylenically unsaturated compound may be, for example, 1% by weight or more, usually It is suitable to be 25% by weight or more, may be 50% by weight or more, may be 75% by weight or more, may be 95% by weight or more, and may be 99% by weight or more. In addition, the weight ratio of the monofunctional monomer in the ethylenically unsaturated compound may be, for example, 99.9% by weight or less, or may be 99.8% by weight or less.

In the aforementioned BP-type hybrid adhesive composition, the ethylenically unsaturated compound may be contained in the form of a partial polymer, or may be contained in the form of an unreacted monomer in its entire amount. The adhesive composition of a preferable aspect contains an ethylenic unsaturated compound in the form of a partial polymer. The polymerization method for partially polymerizing the ethylenically unsaturated compound is not particularly limited. For example, photopolymerization by irradiating light such as ultraviolet rays; radiation polymerization by irradiating radiation such as β rays and γ rays; solution polymerization can be appropriately selected and used. , thermal polymerization such as emulsion polymerization and bulk polymerization; and various conventionally known polymerization methods. From the viewpoint of efficiency and simplicity, photopolymerization is preferably employed. By photopolymerization, the polymerization conversion rate (monomer conversion rate) can be easily controlled by polymerization conditions such as the irradiation amount of light (light amount).

The polymerization conversion rate of the ethylenically unsaturated compound in the above partial polymer is not particularly limited. From the viewpoint of ease of preparation of the adhesive composition, coatability, etc., the above-mentioned polymerization conversion rate is generally about 50% by weight or less, preferably about 40% by weight or less (for example, about 35% by weight or less). The lower limit of the polymerization conversion rate is not particularly limited, but it is typically about 1% by weight or more, usually about 5% by weight or more is appropriate.

A BP-type hybrid adhesive composition comprising a partial polymer of an ethylenically unsaturated compound can be obtained, for example, by making monomers comprising the entire amount of the ethylenically unsaturated compound used for the preparation of the adhesive composition The mixture is partially polymerized by a suitable polymerization method such as photopolymerization. In addition, the BP-type hybrid adhesive composition comprising a partial polymer of an ethylenically unsaturated compound may also be part of a monomer mixture comprising a part of the ethylenically unsaturated compound used in the preparation of the adhesive composition Mixture of polymer with remaining ethylenically unsaturated compounds or part thereof. It should be noted that, in this specification, "complete polymer" means that the polymerization conversion rate is higher than 95% by weight.

The aforementioned partial polymer can be produced, for example, by irradiating an ethylenically unsaturated compound with ultraviolet rays. When the above-mentioned partial polymer is prepared in the presence of a BP polymer, the irradiation conditions of ultraviolet rays are set so that the ethylenically unsaturated groups are reacted and the benzophenone structure is not excited by light, whereby it is possible to obtain An adhesive composition comprising a partial polymer of an ethylenically unsaturated compound and a BP polymer. As the light source, a light source capable of irradiating ultraviolet light that does not contain or has little wavelength components such as the above-mentioned black light lamp and UV-LED lamp can be preferably used.

Moreover, after preparing the partial polymer of an ethylenically unsaturated compound in advance, you may mix this partial polymer with a BP polymer, and you may prepare an adhesive composition. When a part of the polymer is prepared by irradiating an ethylenically unsaturated compound with ultraviolet rays in the absence of a component containing a benzophenone structure, as the ultraviolet light source, both a light source that does not excite the benzophenone structure and a light source that excites the benzophenone structure be usable.

When preparing a partial polymer of an ethylenically unsaturated compound, the reaction of the ethylenically unsaturated group can be accelerated by using a photopolymerization initiator. As the photopolymerization initiator, ketal-based photopolymerization initiators, acetophenone-based photopolymerization initiators, benzoin ether-based photopolymerization initiators, acylphosphine oxide-based photopolymerization initiators, α-ketol-based photopolymerization initiators, Polymerization initiators, aromatic sulfonyl chloride-based photopolymerization initiators, photoactive oxime-based photopolymerization initiators, benzoin-based photopolymerization initiators, benzil-based photopolymerization initiators, benzophenone-based photopolymerization initiators , Alkylphenone-based photopolymerization initiators, thioxanthone-based photopolymerization initiators, and the like. A photopolymerization initiator that absorbs light having a wavelength of 300 nm or more (for example, light having a wavelength of 300 nm or more and 500 nm or less) to generate radicals can be preferably used. A photoinitiator can be used individually by 1 type or in appropriate combination of 2 or more types.

In the aforementioned BP-type hybrid adhesive composition, a photopolymerization initiator may be contained as needed for the purpose of improving or imparting photocurability, or the like. As the photopolymerization initiator, ketal-based photopolymerization initiators, acetophenone-based photopolymerization initiators, benzoin ether-based photopolymerization initiators, acylphosphine oxide-based photopolymerization initiators, α-ketol-based photopolymerization initiators, Polymerization initiators, aromatic sulfonyl chloride-based photopolymerization initiators, photoactive oxime-based photopolymerization initiators, benzoin-based photopolymerization initiators, benzil-based photopolymerization initiators, benzophenone-based photopolymerization initiators , Alkylphenone-based photopolymerization initiators, thioxanthone-based photopolymerization initiators, and the like. A photoinitiator can be used individually by 1 type or in appropriate combination of 2 or more types.

Specific examples of the ketal-based photopolymerization initiator include 2,2-dimethoxy-1,2-diphenylethan-1-one and the like.

Specific examples of the acetophenone-based photopolymerization initiator include: 1-hydroxycyclohexyl-phenyl-ketone, 4-phenoxydichloroacetophenone, 4-tert-butyl-dichloroacetophenone, 1-[ 4-(2-Hydroxyethoxy)-phenyl]-2-hydroxy-2-methyl-1-propane-1-one, 2-hydroxy-2-methyl-1-phenyl-propane-1- ketone, methoxyacetophenone, etc.

Specific examples of benzoin ether-based photopolymerization initiators include benzoin ethers such as benzoin methyl ether, benzoin ethyl ether, benzoin propyl ether, benzoin isopropyl ether, and benzoin isobutyl ether, and Anisoin methyl ether and other substituted benzoin ethers.

Specific examples of acylphosphine oxide-based photopolymerization initiators include bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide, bis(2,4,6-trimethylbenzoyl)-2 ,4-Di-n-butoxyphenylphosphine oxide, 2,4,6-trimethylbenzoyldiphenylphosphine oxide, bis(2,6-dimethoxybenzoyl)-2,4, 4-trimethylpentylphosphine oxide, etc.

Specific examples of the α-ketol-based photopolymerization initiator include: 2-methyl-2-hydroxypropiophenone, 1-[4-(2-hydroxyethyl)phenyl]-2-methylpropane-1-one wait.

Specific examples of the aromatic sulfonyl chloride-based photopolymerization initiator include 2-naphthalenesulfonyl chloride and the like.

Specific examples of the photoactive oxime-based photopolymerization initiator include 1-phenyl-1,1-propanedione-2-(O-ethoxycarbonyl)-oxime and the like.

Specific examples of the benzoin-based photopolymerization initiator include benzoin and the like.

Specific examples of the benzil-based photopolymerization initiator include benzil and the like.

Specific examples of benzophenone-based photopolymerization initiators include: benzoylbenzoic acid, 3,3'-dimethyl-4-methoxybenzophenone, polyvinylbenzophenone, α-hydroxy Cyclohexyl phenyl ketone, etc.

Specific examples of thioxanthone-based photopolymerization initiators include thioxanthone, 2-chlorothioxanthone, 2-methylthioxanthone, 2,4-dimethylthioxanthone, isopropylthioxanthone, 2,4-dichlorothioxanthone, 2,4-diethylthioxanthone, isopropylthioxanthone, 2,4-diisopropylthioxanthone, dodecylthioxanthone, etc.

As the photopolymerization initiator contained in the BP-type hybrid adhesive composition, a photopolymerization initiator that absorbs light with a wavelength of 300 nm or more (for example, light with a wavelength of 300 nm or more and 500 nm or less) to generate radicals can be preferably used. A photoinitiator can be used individually by 1 type or in appropriate combination of 2 or more types. In some embodiments, it may be preferable to use a photopolymerization initiator that does not contain phosphorus in the molecule. The BP-type hybrid adhesive composition may not substantially contain a photopolymerization initiator containing a phosphorus element in a molecule.

The content of the photopolymerization initiator in the BP-type hybrid adhesive composition is not particularly limited, and can be set so as to exhibit a desired effect appropriately. In some embodiments, the content of the photopolymerization initiator may be, for example, about 0.005 parts by weight or more with respect to 100 parts by weight of the monomer components constituting the BP-type hybrid adhesive composition, and generally 0.01 parts by weight or more is suitable. It is preferably 0.05 parts by weight or more, may be 0.10 parts by weight or more, may be 0.15 parts by weight or more, and may be 0.20 parts by weight or more. By increasing the content of the photopolymerization initiator, the photocurability of the BP-type hybrid adhesive composition improves. In addition, with respect to 100 parts by weight of the monomer components constituting the BP-type hybrid adhesive composition, the content of the photopolymerization initiator is generally set to be 5 parts by weight or less, preferably 2 parts by weight or less, and may be 1 part by weight. The weight part or less may be 0.7 weight part or less, and may be 0.5 weight part or less. From the viewpoint of suppressing gelation of the BP-type hybrid adhesive composition, etc., it may be advantageous that the content of the photopolymerization initiator is not too large.

In the aforementioned BP-type hybrid adhesive composition, for example, an isocyanate-based crosslinking agent, an epoxy-based crosslinking agent, an oxazoline-based crosslinking agent, an aziridine-based crosslinking agent, a carbodiimide Crosslinking agent, melamine crosslinking agent, urea crosslinking agent, metal alkoxide crosslinking agent, metal chelate crosslinking agent, metal salt crosslinking agent, hydrazine crosslinking agent, amine crosslinking agent Known crosslinking agent such as linking agent. As crosslinking agents, peroxides can also be used. These crosslinking agents may be used alone or in combination of two or more. The pressure-sensitive adhesive layer A formed from the BP-type hybrid pressure-sensitive adhesive composition containing a cross-linking agent preferably contains the cross-linking agent mainly in a form after a cross-linking reaction. By using a crosslinking agent, the cohesive force of the adhesive layer A, etc. can be adjusted suitably.

The usage-amount when using a crosslinking agent (the total amount when using 2 or more types of crosslinking agents) is not specifically limited. From the viewpoint of realizing an adhesive that exhibits well-balanced adhesive properties such as adhesive force and cohesive force, the amount of the crosslinking agent used is usually About 5 parts by weight or less is suitable, and may be 3 parts by weight or less, 1 part by weight or less, 0.50 parts by weight or less, 0.30 parts by weight or less, or 0.20 parts by weight or less. The lower limit of the usage-amount of a crosslinking agent is not specifically limited, It just needs to be more than 0 weight part with respect to 100 weight part of monomer components which comprise a BP type hybrid adhesive composition. In some embodiments, the amount of the crosslinking agent used may be, for example, 0.001 parts by weight or more, 0.01 parts by weight or more, or 0.05 parts by weight relative to 100 parts by weight of the monomer components constituting the BP-type hybrid adhesive composition. or more, may be 0.10 parts by weight or more.

The aforementioned BP-type hybrid adhesive composition may contain various conventionally known chain transfer agents. As the chain transfer agent, mercaptans such as n-dodecylmercaptan, t-dodecylmercaptan, thioglycolic acid, and α-thioglycerol can be used. Alternatively, a chain transfer agent not containing a sulfur atom (non-sulfur-based chain transfer agent) can also be used. Specific examples of non-sulfur-based chain transfer agents include: anilines such as N,N-dimethylaniline and N,N-diethylaniline; terpenes such as α-pinene and terpinolene; - Styrenes such as methylstyrene and α-methylstyrene dimer; compounds with benzylidene groups such as dibenzylidene acetone, cinnamyl alcohol, and cinnamaldehyde; hydroquinone, 1,4-dihydroxy Hydroquinones such as naphthalene; quinones such as benzoquinone and naphthoquinone; olefins such as 2,3-dimethyl-2-butene and 1,5-cyclooctadiene; phenol, benzyl alcohol, allyl alcohol Alcohols such as diphenylbenzene, triphenylbenzene and other benzyl hydrogens; etc. A chain transfer agent can be used individually by 1 type or in combination of 2 or more types. When using a chain transfer agent, the usage-amount can be about 0.01-1 weight part with respect to 100 weight part of monomer components, for example. It can also preferably be carried out without using a chain transfer agent.

A silane coupling agent is mentioned as another component which may be contained in a BP type hybrid adhesive composition. By using a silane coupling agent, the peeling strength with respect to an adherend (for example, a glass plate) can be improved. In addition, the pressure-sensitive adhesive layer A may contain a silane coupling agent. The adhesive layer A containing a silane coupling agent can be suitably formed using the BP-type hybrid adhesive composition containing a silane coupling agent. A silane coupling agent can be used individually by 1 type or in combination of 2 or more types.

The aforementioned BP-type mixed adhesive composition may contain tackifying resins (such as rosin-based, petroleum-based, terpene-based, phenol-based, ketone-based, etc. tackifying resins), viscosity modifiers (such as tackifiers), fluid Various additives conventional in the adhesive field such as leveling agent, antioxidant, plasticizer, filler, stabilizer, antiseptic, antiaging agent are used as other arbitrary components. Regarding such various additives, conventionally known ones can be used by conventional methods, and since they do not particularly characterize the present invention, detailed description thereof will be omitted.

In addition, the said BP type hybrid adhesive composition can exhibit favorable adhesive force without using the said tackifier resin. Therefore, in some embodiments, the content of the above-mentioned tackifying resin in the above-mentioned adhesive layer or adhesive composition can be set to be lower than 10 weight parts, and further lower than 5 weight parts, for example, with respect to 100 weight parts of monomer components. share. The content of the above-mentioned tackifying resin may be less than 1 part by weight (for example, less than 0.5 part by weight), or less than 0.1 part by weight (0 part by weight or more and less than 0.1 part by weight). The above-mentioned pressure-sensitive adhesive layer or pressure-sensitive adhesive composition may not contain a tackifying resin.

By curing the aforementioned BP-type hybrid adhesive composition, an adhesive layer A containing a BP polymer (hereinafter sometimes referred to as "BP-type adhesive layer A") can be formed. The curing of the BP-type hybrid adhesive composition is preferably such that the ethylenically unsaturated groups contained in the adhesive composition react and the benzophenone structure contained in the BP-type hybrid adhesive composition remains. way. The above curing can be preferably performed by irradiation of active energy rays. The active energy rays for forming the pressure-sensitive adhesive layer A are preferably ultraviolet rays, and more preferably ultraviolet rays that do not contain a component with a wavelength of less than 300 nm or have a small amount of the wavelength component.

The BP-type pressure-sensitive adhesive layer A was produced using the aforementioned BP-type hybrid pressure-sensitive adhesive composition. The BP-type adhesive layer A may contain a BP polymer and a polymer derived from an ethylenically unsaturated compound. In some preferred embodiments, the aforementioned BP-type hybrid adhesive composition may be a composition in which the aforementioned ethylenically unsaturated compound does not contain ethylenically unsaturated BP. According to the BP-type hybrid adhesive composition having such a composition, it is possible to produce a BP-type adhesive layer A comprising a BP polymer and a polymer derived from an ethylenically unsaturated compound, wherein the polymer is a non-BP polymer.

The method of manufacturing the BP-type adhesive layer A from the BP-type mixed adhesive composition can be carried out by the following method: In the adhesive layer forming process and the adhesive layer curing process in the above-mentioned second embodiment, using A BP-type hybrid adhesive composition replaces the base polymer.

Regarding the curing conditions in the adhesive layer curing step of the present embodiment, in order to react the above-mentioned ethylenically unsaturated groups and leave the benzophenone structure, it is preferable to use a black light lamp, a UV-LED lamp, etc. that can irradiate A light source of ultraviolet rays with a wavelength below 300nm or a small amount of such wavelength components.

<Self-luminous display device>

The self-luminous display device according to the second aspect of the present invention is a display device in which a large number of minute light-emitting elements are arranged on a wiring board, and each light-emitting element is selectively emitted light by a light-emitting control means connected thereto. Visual information such as text/image/video is directly displayed on the display screen through the flickering of each light emitting element. Examples of self-luminous display devices include mini/micro LED display devices and organic EL (electroluminescence) display devices. The photocurable pressure-sensitive adhesive sheet A of the first aspect of the present invention is particularly suitable for use in the manufacture of mini/micro LED display devices.

4 is a schematic diagram (cross-sectional view) showing an embodiment of a self-luminous display device (mini/micro LED display device) of the second aspect of the present invention.

In FIG. 4 , the mini/micro LED display device 2A is composed of the following components: a display panel in which a plurality of LED chips 23 are arranged on one side of a substrate 21 via a metal wiring layer 22 ; The adhesive layer 20 which seals the some LED chip 23, and the covering member 24 laminated|stacked on the upper part (image display side) of this adhesive layer 20. The covering member 24 is not particularly limited, and may be made of the same material as the above-mentioned "base material".

In the mini/micro LED display device 2A of this embodiment, a metal wiring layer 22 for transmitting light emission control signals to each LED chip 23 is stacked on the substrate 21 of the display panel. LED chips 23 emitting red (R), green (G), and blue (B) colored light are alternately arranged on the substrate 21 of the display panel with metal wiring layers 22 interposed therebetween. The metal wiring layer 22 is formed of metal such as copper, and reflects light emitted by each LED chip 23 to degrade image visibility. In addition, the light emitted by the LED chips 23 of the respective colors of RGB is mixed, and the contrast is lowered.

In the mini/micro LED display device 2A of this embodiment, the LED chips 23 arranged on the display panel are sealed by the adhesive layer 20 . The adhesive layer 20 is comprised from the hardened|cured material of the adhesive layer A of this invention. The adhesive layer 20 sufficiently follows the fine level difference between the plurality of LED chips 23 and seals without gaps.

The pressure-sensitive adhesive layer 20 has sufficient light-shielding properties in the visible light region. The fine height difference between the LED chips 23 is sealed without gaps by the adhesive layer 20 with high light-shielding properties, so reflection by the metal wiring layer 22 can be prevented, color mixing between the LED chips 23 can be prevented, and contrast can be improved.

In addition, since the pressure-sensitive adhesive layer 20 is a cured product of the pressure-sensitive adhesive layer A, it is excellent in workability. Therefore, it is possible to suppress adhesive shortage during cutting of the mini/micro LED display device 2A according to this embodiment, and protruding and sagging of the adhesive layer 20 from the end during storage.

The self-luminous display device (mini/micro LED display device) of this embodiment may include optical members other than the display panel, the adhesive layer, and the cover member. It does not specifically limit as said optical member, A polarizing plate, a retardation film, an antireflection film, a viewing angle adjustment film, an optical compensation film etc. are mentioned. It should be noted that the optical member also includes members (appearance film, decorative film, surface protection plate, etc.) that maintain the visibility of the display device and input device and perform decoration and protection functions.

The self-luminous display device (mini/micro LED display device) of this embodiment is not particularly limited, but can preferably be produced by a method including the following steps.

(1) A step of laminating the adhesive layer A of the photocurable adhesive sheet A on a display panel in which a plurality of light emitting elements are arrayed on one side of the substrate, and sealing the light emitting elements with the adhesive layer A.

(2) A step of irradiating and curing the pressure-sensitive adhesive layer with radiation.

5 is a diagram schematically showing the steps of one embodiment of the method for manufacturing a self-luminous display device (mini/micro LED display device) on the second aspect of the present invention. In this embodiment, as shown in FIG. 5( a ), a photocurable adhesive sheet 1E on the second side of the present invention is used, and a plurality of light-emitting elements are arranged on one side of a substrate 21 with a metal wiring layer 22 interposed therebetween. (LED chips) 23 display panels.

In this embodiment, the photocurable adhesive sheet 1E is comprised from the adhesive layer 10 and the covering member 24 which can be manufactured by the manufacturing method of the photocurable adhesive sheet A of 2nd Embodiment of this invention. The pressure-sensitive adhesive layer 10 has a configuration in which a crosslinking agent 11 and a photopolymerization initiator 12 are dissolved in a base polymer. An aspect in which only one of the crosslinking agent 11 and the photopolymerization initiator 12 is dissolved in the pressure-sensitive adhesive layer 10 is also included in this embodiment. In the present embodiment, there is a concentration gradient of the crosslinking agent 11 and the photopolymerization initiator 12 in the thickness direction from the main surface 10A of the pressure-sensitive adhesive layer 10 in contact with the support body S3.

In the present embodiment, the photocurable pressure-sensitive adhesive sheet 1E has the covering member 24 , but the covering member 24 may not be required. The cover member 24 is not particularly limited, and may be made of the same material as the above-mentioned "substrate", or may be a release film (separator).

Next, as shown in (b) of FIG. 5 , the main surface 10B of the adhesive layer 10 of the photocurable adhesive sheet 1E on which the covering member 24 is not laminated is laminated on the surface of the display panel on which a plurality of LED chips are arranged, The LED chip 23 and the metal wiring layer 22 are sealed with the adhesive layer 10 . This lamination can be performed by a known method, and can be performed, for example, under heating and pressing conditions using an autoclave. The pressure-sensitive adhesive layer 10 of the photocurable pressure-sensitive adhesive sheet 1E has high fluidity and exhibits excellent level difference absorption. Therefore, the adhesive layer 10 seals so that the level difference between the metal wiring layer 22 and the plurality of LED chips 23 can be filled without gaps.

Next, as shown in FIG. 5( c ), the adhesive layer 10 is irradiated with radiation to be cured. By irradiation with radiation, the photopolymerization initiator 12 decomposes to generate radicals, ions, etc., and initiates a polymerization/crosslinking reaction of the crosslinking agent 12 . The radiation is not particularly limited as long as the pressure-sensitive adhesive layer 10 is cured, but ultraviolet rays through which the pressure-sensitive adhesive layer 10 exhibits transparency are preferable. That is, the adhesive layer 10 has high light-shielding properties for visible light and high transmittance for ultraviolet rays, so the adhesive layer 10 can be cured by ultraviolet rays. (c) of FIG. 5 is an embodiment in which the adhesive layer 10 is cured by irradiating ultraviolet rays U.

The ultraviolet rays are preferably ultraviolet rays having a wavelength of 200 to 400 nm, more preferably ultraviolet rays having a wavelength of 330 to 400 nm. In addition, when the pressure-sensitive adhesive layer 10 is composed of the BP-type pressure-sensitive adhesive layer A, it can be cured by irradiating ultraviolet rays containing wavelength components capable of exciting the benzophenone structure. A source of ultraviolet light with a wavelength below 300nm.

As a light source for ultraviolet irradiation, for example, a high-pressure mercury lamp, a low-pressure mercury lamp, a microwave excitation type lamp, a metal halide lamp, a chemical lamp, a black light lamp, or an LED can be used. In addition, the irradiation time and irradiation method of ultraviolet rays can be appropriately set as long as the adhesive layer 10 can be cured without adversely affecting the display panel, and the adhesive layer 10 can be cured to exhibit sufficient processability. . For example, the irradiation amount (cumulative light amount) of ultraviolet rays is preferably 1000 mJ/cm ² to 10000 mJ/cm ² , more preferably 2000 mJ/cm ² to 4000 mJ/cm ² , and still more preferably 3000 mJ/cm ² .

By curing the adhesive layer 10, as shown in FIG. 5(d), a self-luminous display device (mini/micro LED display device) 2B can be obtained. In (d) of FIG. 5 , the adhesive layer 20 is an adhesive layer obtained by curing the adhesive layer 10 . The self-luminous display device (mini/micro LED display device) 2B is an embodiment showing an example of the self-luminous display device (mini/micro LED display device) of the second aspect of the present invention.

When the adhesive layer 10 is cured, the crosslinking agent 11 is crosslinked/polymerized to form a crosslinked structure 11 ′ to form the adhesive layer 20 . The processability of the pressure-sensitive adhesive layer 20 is improved, and it is possible to suppress adhesive shortage at the time of cutting, and protruding and sagging of the pressure-sensitive adhesive layer from the edge during storage. In addition, the adhesive layer 20 can suppress the generation of gases such as carbon dioxide due to heating of the display panel, prevent the generation of air bubbles, and improve adhesion reliability.

In addition, in the embodiment of FIG. 5( d ), the side of the main surface of the pressure-sensitive adhesive layer 20 in contact with the support body S3 has a higher crosslinking density than the main surface on the opposite side. This configuration is preferable in that, for example, the bendability can be improved when a self-luminous display device (mini/micro LED display device) is used as an outwardly curved flexible image display device.

That is, when a flexible display is bent, generally tensile stress is applied to the outside and compressive stress is applied to the inside, and the outside stress is stronger than the inside stress. Therefore, by arranging the upper portion (image display side) of the adhesive layer 20 on the outside when the flexible display is bent, durability against bending can be improved.

Example

Hereinafter, although an Example demonstrates this invention in more detail, this invention is not limited to these Examples.

[Example 1]

(prepolymer preparation)

67 parts by weight of butyl acrylate (BA), 14 parts by weight of cyclohexyl acrylate (CHA), 4-hydroxy After 19 parts by weight of butyl ester (4-HBA), 0.09 parts by weight of a photopolymerization initiator (manufactured by BASF Corporation, trade name "Irgacure 184"), and 0.09 parts by weight of a photopolymerization initiator (manufactured by BASF Corporation, trade name "Irgacure 651") , nitrogen gas was flowed, and nitrogen substitution was performed for about 1 hour while stirring. Then, UVA was irradiated at 5 mW/cm ² to carry out polymerization, and the reaction rate was adjusted to 5 to 15%, to obtain an acrylic prepolymer solution A.

(Preparation of Adhesive Composition)

Add 9 parts by weight of 2-hydroxyethyl acrylate (HEA), 4-hydroxybutyl acrylate (4-HBA) 8 parts by weight, 0.02 parts by weight of dipentaerythritol hexaacrylate (manufactured by Shin-Nakamura Industrial Chemicals, trade name "KAYARAD DPHA") as a polyfunctional monomer, silane coupling agent (3-glycidoxypropyltrimethoxysilane , Shin-Etsu Chemical Co., Ltd., trade name "KBM-403") 0.35 parts by weight and a photopolymerization initiator (BASF Corporation, "Irgacure 651") 0.45 parts by weight to obtain an adhesive composition B.

(Preparation of black adhesive composition)

5.8 parts by weight of a 20% dispersion of a black pigment (manufactured by TOKUSHIKI "9256BLACK") and 0.2 parts by weight of an additional photopolymerization initiator (manufactured by BASF Corporation, "Irgacure 651") were added to 100 parts by weight of the above-mentioned adhesive composition B. , to obtain a black adhesive composition C.

(production of adhesive sheet)

On the release surface of release film R1 (manufactured by Mitsubishi Plastics Corporation, trade name "MRF#38") with a thickness of 38 μm and one side of the polyester film is the release surface, the black adhesive composition C prepared above is coated and covered. One side of the polyester film was a release film R2 (MRE#38, manufactured by Mitsubishi Plastics Corporation) that was a release surface, and air was blocked. Ultraviolet rays were irradiated from one side of the laminated body using a black light lamp (manufactured by Toshiba Corporation, trade name FL15BL) under conditions of an illuminance of 5 mW/cm ² and a cumulative light intensity of 1300 mJ/cm ² . Thus, an adhesive sheet D in which an adhesive layer having a thickness of about 50 μm, which is a cured product of the black adhesive composition C described above, is sandwiched between the release films R1 and R2 was obtained as a base-less double-sided adhesive sheet. .

In addition, the illuminance value of the said black light lamp is the measured value based on the peak sensitivity wavelength of about 350 nm industrial UV inspection equipment (TOPCON company make, trade name: UVR-T1, the light receiving part model UD-T36).

(Production of Photocurable Adhesive Sheet)

The peeling film R2 of the above-mentioned pressure-sensitive adhesive sheet D was peeled off, and a photopolymerization initiator (manufactured by BASF, trade name "Irgacure 651") was coated with a wire wound rod type #7 bar coater manufactured by RD Specialties Co., Ltd. A solution (a target wet coating thickness of 15 μm) was dissolved in trimethylolpropane triacrylate (TMPTA) so as to be 5% by weight. After coating, it was heated in an oven at 110° C. for 2 minutes. Then, the adhesive surface was protected again with the peeling film R2, and the photocurable adhesive sheet E containing the adhesive layer which melt|dissolved TMPTA and the photoinitiator was obtained as a substrate-less double-sided adhesive sheet.

[Example 2]

(Preparation of Solvent Type Black Adhesive Composition)

60 parts by weight of n-butyl acrylate (BA), 6 parts by weight of cyclohexyl acrylate (CHA), N-ethylene 18 parts by weight of base-2-pyrrolidone (NVP), 1 part by weight of isostearyl acrylate (iSTA), 15 parts by weight of 4-hydroxybutyl acrylate (4HBA), 0.125 parts by weight of α-thioglycerol as a chain transfer agent and 122 parts by weight of ethyl acetate as a polymerization solvent, and 0.2 parts by weight of 2,2'-azobisisobutyronitrile (AIBN) as a thermal polymerization initiator, and carry out solution polymerization under a nitrogen atmosphere, thereby obtaining A solution of about 500,000 acrylic polymers.

To the solution obtained above, 0.22 parts by weight of a polymerization initiator (manufactured by BASF Corporation, "Irgacure 651") and 0.27 parts by weight based on solid content were added to 100 parts of monomer components used in the preparation of the solution. Isocyanate-based crosslinking agent (trimethylolpropane/xylylene diisocyanate adduct, manufactured by Mitsui Chemicals, Inc., trade name "TAKENATE D-110N", solid content concentration 75%), dipentaerythritol hexaacrylate (manufactured by Shin-Nakamura Industrial Chemicals, trade name "KAYARAD DPHA") 2.2 parts by weight, polypropylene glycol #400 diacrylate (manufactured by Shin-Nakamura Industrial Chemicals) 1 part by weight, silane coupling agent (3-glycidoxypropyltrimethoxy silane, Shin-Etsu Chemical Co., Ltd., trade name "KBM-403") 0.33 parts by weight, antioxidant (BASF Corporation, trade name "IRGANOX1135") 0.3 parts by weight, polyether polyol (ADEKA, trade name " ADEKA Polyether EPD-300") 0.18 parts by weight and 4 parts by weight of a 20% dispersion of a black pigment (manufactured by TOKUSHIKI "9170BLACK") to obtain a solvent-based black adhesive composition.

(Production of Photocurable Adhesive Sheet)

Two sheets of a 38-μm-thick release film (manufactured by Mitsubishi Plastics Corporation, MRF#38) whose one side of the polyester film was a release surface were prepared. Apply the above-prepared solvent-based black adhesive composition on the peeling surface of the first release film, and dry at 60°C for 3 minutes, then at 120°C for 3 minutes to form a photocurable adhesive with a thickness of 134 μm layer. The peeling surface of the 2nd peeling film was stuck and protected on this pressure-sensitive adhesive layer, and the photocurable pressure-sensitive adhesive sheet was obtained as a substrate-less double-sided pressure-sensitive adhesive sheet.

[Example 3]

(Preparation of Adhesive Composition)

An acrylic copolymer having a benzophenone structure in the side chain (manufactured by BASF Corporation, trade name "acResin A260UV", Tg: -39 ℃, Mw: 19×10 ⁴ , BP equivalent: 2 mg/g) 50 parts by weight, butyl acrylate (BA) 26 parts by weight, N-vinyl-2-pyrrolidone (NVP) 8 parts by weight, isobornyl acrylate ( 16 parts by weight of IBXA) and 0.2 parts by weight of a photopolymerization initiator (manufactured by BASF Corporation, brand name "Irgacure 184") were mixed to prepare an adhesive composition.

(Preparation of black adhesive composition)

2 parts by weight of a 20% dispersion of a black pigment ("9256 BLACK" manufactured by TOKUSHIKI) was added to 100 parts by weight of the above-mentioned adhesive composition to prepare a black adhesive composition.

(Production of Photocurable Adhesive Sheet)

The black adhesive composition prepared above was coated on the peeling surface of a 38 μm-thick peeling film R1 (manufactured by Mitsubishi Plastics Corporation, trade name "MRF#38") that serves as the peeling surface on one side of the polyester film, covering the polyester film. The release film R2 (manufactured by Mitsubishi Plastics Corporation, MRE#38) whose one side of the film was the release surface cut off the air. Ultraviolet rays were irradiated from one side of the laminated body using a black light lamp (manufactured by Toshiba Corporation, trade name FL15BL) under conditions of an illuminance of 5 mW/cm ² and a cumulative light intensity of 1300 mJ/cm ² . As a result, a photocurable bond in which an adhesive layer having a thickness of about 104 μm, which is a cured product of the black adhesive composition described above, is sandwiched between the release films R1 and R2 was obtained in the form of a base-less double-sided adhesive sheet. piece.

[Example 4]

(Preparation of black adhesive composition)

To 100 parts by weight of the adhesive composition B prepared in Example 1, 4 parts by weight of a 20% dispersion of a black pigment (manufactured by TOKUSHIKI "9256BLACK") and an additional photopolymerization initiator (manufactured by BASF "Irgacure 651") were added. 0.2 parts by weight, 1 part of 4-acryloyloxybenzophenone manufactured by Ark Pharm Co., Ltd., to obtain a black adhesive composition.

(Production of Photocurable Adhesive Sheet)

The black adhesive composition prepared above was coated on the peeling surface of a 38 μm-thick peeling film R1 (manufactured by Mitsubishi Plastics Corporation, trade name "MRF#38") that serves as the peeling surface on one side of the polyester film, covering the polyester film. The release film R2 (manufactured by Mitsubishi Plastics Corporation, MRE#38) whose one side of the film was the release surface cut off the air. Ultraviolet rays were irradiated from one side of the laminated body using a black light lamp (manufactured by Toshiba Corporation, trade name FL15BL) under conditions of an illuminance of 5 mW/cm ² and a cumulative light intensity of 1300 mJ/cm ² . Thus, a PSA sheet in which an PSA layer having a thickness of about 100 μm as a cured product of the black PSA composition was sandwiched between the release films R1 and R2 was obtained as a substrate-less double-sided PSA sheet.

In addition, the illuminance value of the said black light lamp is the measured value based on the peak sensitivity wavelength of about 350 nm industrial UV inspection equipment (TOPCON company make, trade name: UVR-T1, the light receiving part model UD-T36).

[Example 5]

Except having made 2 parts of 4-acryloxybenzophenone, it carried out similarly to Example 4, and produced the photocurable adhesive sheet.

[Reference example 1]

(Preparation of Adhesive Composition)

Add 9 parts by weight of 2-hydroxyethyl acrylate (HEA), 4-hydroxybutyl acrylate (4- HBA) 8 parts by weight, 0.45 parts by weight of a polymerization initiator (manufactured by BASF Corporation, "Irgacure 651"), and 1 part by weight of nano-silica (manufactured by Japan Aerosil Co., Ltd., trade name "R976S"). agent composition.

(Preparation of black adhesive composition)

5.8 parts by weight of a 20% dispersion of a black pigment (manufactured by TOKUSHIKI "9256BLACK") and 0.2 parts by weight of an additional photopolymerization initiator (manufactured by BASF Corporation, "Irgacure 651") were added to 100 parts by weight of the above-mentioned adhesive composition, A black adhesive composition was obtained.

(production of adhesive sheet)

The black adhesive composition prepared above was coated on the release surface of a release film R1 (manufactured by Mitsubishi Plastics Corporation, trade name "MRF#38") with a thickness of 38 μm and one side of the polyester film was the release surface, covering the polyester film. The release film R2 (MRE#38, manufactured by Mitsubishi Plastics Corporation) whose one side of the ester film was the release surface cut off the air. Ultraviolet rays were irradiated from one side of the laminated body using a black light lamp (manufactured by Toshiba Corporation, trade name FL15BL) under conditions of an illuminance of 5 mW/cm ² and a cumulative light intensity of 1300 mJ/cm ² . Thus, a PSA sheet in which an PSA layer having a thickness of about 100 μm as a cured product of the black PSA composition was sandwiched between the release films R1 and R2 was obtained as a substrate-less double-sided PSA sheet. In addition, the obtained pressure-sensitive adhesive sheet did not show photocurability.

[Reference example 2]

A pressure-sensitive adhesive sheet was obtained in the same manner as in Reference Example 1 except that the amount of nano silica used was 3 parts by weight.

[Reference example 3]

A pressure-sensitive adhesive sheet was obtained in the same manner as in Reference Example 1 except that the amount of nano silica used was 5 parts by weight.

[Reference example 4]

A pressure-sensitive adhesive sheet was obtained in the same manner as in Reference Example 1 except that the amount of nano silica used was 7 parts by weight.

It should be noted that the purpose of Reference Examples 1 to 4 is to verify the storage modulus and its ratio for achieving both height difference followability and processability. The storage modulus was changed according to the amount of silica used and evaluated.

[Comparative example 1]

(production of adhesive sheet)

The adhesive composition B prepared in Example 1 was applied to the peeling surface of a peeling film R1 (manufactured by Mitsubishi Plastics Corporation, trade name "MRF#38") having a thickness of 38 μm as the peeling surface on one side of the polyester film, The release film R2 (manufactured by Mitsubishi Plastics Corporation, MRE#38) covering one side of the polyester film as the release surface was shielded from the air. Ultraviolet rays were irradiated from one side of the laminated body using a black light lamp (manufactured by Toshiba Corporation, trade name FL15BL) under conditions of an illuminance of 5 mW/cm ² and a cumulative light intensity of 1300 mJ/cm ² . Thus, a PSA sheet in which a PSA layer having a thickness of about 50 μm as a cured product of the PSA composition B was sandwiched between the release films R1 and R2 was obtained as a base-less double-sided PSA sheet.

(Production of Photocurable Adhesive Sheet)

The release film R2 of the above-mentioned pressure-sensitive adhesive sheet was peeled off, and a photopolymerization initiator (manufactured by BASF Corporation, trade name "Irgacure 651") was coated using a wire wound rod type, #7 bar coater manufactured by RD Specialties Co., Ltd. A solution (a target wet coating thickness of 15 μm) was dissolved in trimethylolpropane triacrylate (TMPTA) so as to be 5% by weight. After coating, it was heated in an oven at 110° C. for 2 minutes. Then, the adhesive surface was protected again with release film R2, and the photocurable adhesive sheet containing the adhesive layer which melt|dissolved TMPTA and a photoinitiator was obtained as a substrate-less double-sided adhesive sheet.

[Comparative example 2]

The PSA sheet D obtained in Example 1 was used as the PSA sheet of Comparative Example 2. In addition, the pressure-sensitive adhesive sheet D did not show photocurability.

(evaluate)

The following evaluations were performed using the PSA sheets obtained in the above Examples, Reference Examples, and Comparative Examples. The evaluation method is shown below. The results are shown in Table 1.

[Evaluation of transmittance]

The release film on one side was peeled off from the adhesive sheet, and an alkali-free glass was bonded to the exposed side. Then, the release film on the other side was peeled off from the adhesive sheet to obtain a sample in which the adhesive sheet was bonded to the non-alkali glass plate.

The total light transmittance was measured using a haze meter (manufactured by Murakami Color Science Laboratory Co., Ltd., trade name "HN-150") according to the method specified in JIS K7361.

[Evaluation of storage modulus]

The ARES GII of TA Instruments was used for evaluation.

The pressure-sensitive adhesive sheets laminated to a thickness of about 1 mm are sandwiched between 8 mm parallel plates, and the 10°C, 25 The storage modulus G' at °C and 85°C was taken as the storage modulus G' before curing (G'b10, G'b25, G'b85).

Regarding the storage modulus G' after curing, a sheet obtained by irradiating a high-pressure mercury lamp with a pressure-sensitive adhesive sheet sandwiched by release films so that the cumulative light intensity was 3000 mJ/cm ² was laminated to a thickness of about 1 mm. Evaluation was performed in the same manner as above, and it was set as storage modulus G' after curing (G'a10, G'a25, G'a85).

This accumulated light amount is a measured value based on an industrial UV inspection device (manufactured by TOPCON Corporation, trade name: UVR-T1, light-receiving part model UD-T36) with a peak sensitivity wavelength of about 350 nm.

In addition, since the pressure-sensitive adhesive sheets of Reference Examples 1-4 and Comparative Example 2 did not show photocurability, the storage elastic modulus G' after hardening was not evaluated.

[evaluation of altitude difference followability]

(Production of concave-convex adherends)

A laminate of TAC film (thickness 60 μm) and adhesive (thickness 20 μm) was bonded to a glass plate of 45 mm × 50 mm, and a CO ₂ laser (wavelength 10.6 μm/laser diameter 0 μm) was applied to the central 10 mm × 10 mm glass plate. Linear etching was performed at a pitch of 150 μm in the longitudinal direction/a pitch of 225 μm in the lateral direction, thereby obtaining an adherend A in which the TAC film and the adhesive layer were processed into a grid-like concave-convex shape.

This adherend A imitates an LED panel in which a plurality of LED thin films are arranged on a substrate.

(production of adhesive sheet)

The pressure-sensitive adhesive sheets produced in Examples 1 and 3, Reference Examples 1 to 4, and Comparative Examples 1 and 2 were laminated to have a thickness of about 200 μm. The pressure-sensitive adhesive sheet prepared in Example 2 was laminated so as to have a thickness of about 250 μm. The release film on one surface of these laminated pressure-sensitive adhesive sheets was peeled off, and a PET film with a thickness of 75 μm was attached to the exposed surface.

(vacuum bonding)

Using a vacuum bonding device (manufactured by CRIMB Products, SE340aaH), the exposed adhesive surface and the processed surface of the adherend A can be completely covered with the adhesive sheet The adherends A were bonded with precision within the processing range to obtain evaluation samples consisting of PET film/laminated adhesive sheet/adherend A, respectively. Furthermore, autoclave treatment (50 degreeC/0.5MPa conditions, 60 minutes) was performed and it adhered.

(evaluation of height difference followability)

In the above-mentioned evaluation samples, the processed portion of the adherend A is recognized as transparent when the PSA sheet can follow the concave-convex pattern portion, and the processed portion of the adherend A is recognized as white, and the white portion is calculated by shooting with a fixed-point camera. Evaluate the height difference followability.

Height difference followability (%)=100-{[area of white portion at the time of evaluation]/[area of white portion before lamination=1cm ² ]×100}

[evaluation of workability]

(Preparation of laminated products for processability evaluation)

The release film of the laminated pressure-sensitive adhesive sheet produced in the item of evaluation of height difference followability was peeled off, and it bonded to the fr-4 board|substrate (thickness 1.2 mm) manufactured by MISUMI Corporation. After autoclave processing (15 minutes on 50 degreeC/0.5MPa condition), the ultraviolet ray was irradiated to Examples 1-3 and the comparative example 1 which showed photocurability. The irradiation conditions of ultraviolet rays were a high-pressure mercury lamp and a cumulative light intensity of 3000 mJ/cm ² . In addition, this integrated light quantity is a measured value based on the industrial UV inspection apparatus (made by TOPCON Corporation, brand name: UVR-T1, light-receiving part model UD-T36) of peak sensitivity wavelength about 350 nm.

(processing)

The laminate for processability evaluation obtained above was cut|disconnected using DTF6450 manufactured by Disco Corporation. Cutting conditions were set to blade type P1A861 (abrasive grain #400), measuring rod 30krpm, speed 30mm/s, and cooling water 1L/min.

(evaluation of workability)

Using a solid microscope, the cut end was observed from the side of the laminated adhesive sheet, and the workability was evaluated by the amount of glue overflowing from the cut end. The evaluation criteria were as follows.

○: 0～150μm

△: 150～200μm

×: 200μm or more

[evaluation of reflectance]

Create a laminated black acrylic board with aluminum foil attached. The peeling film on one surface of the pressure-sensitive adhesive sheet produced in Examples 1 to 3 and Comparative Examples 1 and 2 was peeled off, and a PET film with a thickness of 75 μm was attached to the exposed surface. The release film on the other side of these was peeled off, and the exposed adhesive surface was laminated|stacked on the aluminum foil side of the said plate, and it was set as a sample. For the obtained sample, the PET film was set on the light source side in a spectrophotometer U4100 (manufactured by Hitachi High-Technologies Corporation), and the reflectance (%) in the visible region of 5° regular reflection was measured.

[Table 1]

Examples 1 to 5 belonging to photocurable pressure-sensitive adhesive sheets showed excellent step followability (step absorbability) and workability. As seen from Reference Examples 1 to 4 and Comparative Example 2, when the storage elastic modulus at 85° C. before curing is less than 65 kPa, the step followability (step absorbability) is improved. In addition, as can be seen from Reference Examples 1 to 4, the storage modulus (G'b85) at 85°C before curing is lower than 65kPa, and the storage modulus (G'a10) at 10°C after curing is less than 65kPa. In the region where the storage modulus (G'b85) ratio (G'a10/G'b85) at 85°C before curing is higher than 3.3, it exhibits excellent height difference followability (height difference absorption) and processability . It should be noted that the pressure-sensitive adhesive sheets of Reference Examples 1 to 4 did not show photocurability, so the ratio of the storage modulus (G'b10) at 10°C before curing to the storage modulus at 85°C before curing was used. The ratio (G'b10/G'b85) of the amount (G'b85) was evaluated.

Comparative Example 1, which is a photocurable pressure-sensitive adhesive sheet, exhibited excellent step followability (step absorbability) and processability, but had high reflectance because it did not contain a black pigment.

Variations of the present invention are appended below.

[Appendix 1] A photocurable adhesive sheet comprising an adhesive layer cured by irradiation with radiation,

The aforementioned adhesive layer contains a coloring agent,

The maximum value of the transmittance of the aforementioned adhesive layer at a wavelength of 200 to 400 nm is greater than the maximum value of the transmittance at a wavelength of 400 to 700 nm,

The storage modulus (G'b85) of the aforementioned adhesive layer before curing at 85°C is lower than 65kPa,

The storage modulus (G'a10) of the aforementioned adhesive layer after curing at 10°C and the storage modulus (G'b85) of the aforementioned adhesive layer before curing at 85°C satisfy the following relationship (1).

3.3<G'a10/G'b85 (1)

[Additional Note 2] The photocurable adhesive sheet according to Additional Note 1, wherein the colorant has a maximum value of transmittance at a wavelength of 200 to 400 nm greater than a maximum value of transmittance at a wavelength of 400 to 700 nm of colorants.

[Additional Note 3] The photocurable pressure-sensitive adhesive sheet according to Additional Note 1 or 2, wherein the curing by radiation irradiation is curing by ultraviolet irradiation of 3000 mJ/cm ² in terms of cumulative light intensity.

[Additional Note 4] The photocurable adhesive sheet according to any one of Additional Notes 1 to 3, wherein the storage modulus (G'a10) at 10° C. of the adhesive layer after curing is: Above 90kPa.

[Appendix 5] The photocurable adhesive sheet according to any one of Appendices 1 to 4, wherein the adhesive layer contains a base polymer, a crosslinking agent, and a photopolymerization initiator.

[Additional note 6] The photocurable pressure-sensitive adhesive sheet according to additional note 5, wherein the base polymer contains an acrylic polymer.

[Additional Note 7] The photocurable adhesive sheet according to Additional Note 5 or 6, wherein the crosslinking agent contains a polyfunctional (meth)acrylate.

[Appendix 8] The photocurable adhesive sheet according to any one of Appendices 5 to 7, wherein the adhesive layer is a single sheet formed of the base polymer and has two opposing principal surfaces. layer,

When the adhesive layer of the aforementioned single layer is equally divided into two parts along the thickness direction,

The concentration of the aforementioned crosslinking agent and/or the aforementioned photopolymerization initiator in one of the aforementioned two main surfaces, that is, the area to which the first main surface belongs, and the concentration of the aforementioned crosslinking agent and/or the aforementioned crosslinking agent and/or the aforementioned area where the second main surface belongs The concentrations of the foregoing photopolymerization initiators vary.

[Additional note 9] The photocurable adhesive sheet according to additional note 8, wherein the single-layer adhesive layer has a concentration gradient of the crosslinking agent and/or the photopolymerization initiator in the thickness direction.

[Additional Note 10] A method for producing the photocurable adhesive sheet according to Additional Note 8 or 9, comprising the steps of:

forming an adhesive layer of a single layer formed of the aforementioned base polymer,

curing the aforementioned adhesive layer,

preparing a solution of the aforementioned crosslinking agent and/or the aforementioned photopolymerization initiator,

Coating the aforementioned solution on one side of the aforementioned cured adhesive layer, allowing the aforementioned crosslinking agent and/or the aforementioned photopolymerization initiator contained in the solution to penetrate from the aforementioned one side of the aforementioned adhesive layer along the thickness direction,

The aforementioned adhesive layer is dried.

[Supplementary Note 11] The photocurable adhesive sheet according to any one of Supplementary Notes 1 to 4, wherein the pressure-sensitive adhesive layer contains a polymer having a benzophenone structure in a side chain.

[Appendix 12] The photocurable adhesive sheet according to Appendix 11, wherein the adhesive layer is an adhesive containing an ethylenically unsaturated compound and a polymer having a benzophenone structure in a side chain The cured product of the composition.

[Appendix 13] A self-illuminating display device comprising:

a display panel in which a plurality of light emitting elements are arranged on one side of a substrate; and

The photocurable adhesive sheet according to any one of Supplements 1 to 9, 11, and 12,

The light-emitting element of the aforementioned display panel is sealed by the adhesive layer of the aforementioned photocurable adhesive sheet,

The foregoing adhesive layer is cured.

[Supplementary Note 14] The self-luminous display device according to Supplementary Note 13, wherein the display panel is an LED panel in which a plurality of LED chips are arranged on one side of a substrate.

[Supplementary Note 15] A method for manufacturing the self-luminous display device described in Supplementary Note 13 or 14, which includes the following steps:

The adhesive layer of the photocurable adhesive sheet described in any one of Supplements 1 to 9, 11 and 12 is laminated on a display panel in which a plurality of light-emitting elements are arranged on one side of the substrate, and the adhesive layer is used to The process of sealing the aforementioned light-emitting element; and

A step of curing the pressure-sensitive adhesive layer by irradiating it with radiation.

[Supplementary note 16] The manufacturing method according to supplementary note 15, wherein the radiation is ultraviolet rays.

Industrial availability

The photocurable adhesive sheet of the present invention is suitable for sealing light-emitting elements of self-luminous display devices such as mini/micro LEDs.

Explanation of reference signs

1A～1E Photocurable adhesive sheet

10 adhesive layer

10a～10c Adhesive layer

11 Cross-linking agent

12 photopolymerization initiator

13 Solvent

14 solution

2A, 2B self-luminous display device (mini/micro LED display device)

20 adhesive layer

21 Substrate

22 metal wiring layer

23 Light-emitting components (LED chips)

24 Covering components

S1, S2 Support body (peeling film)

Claims (16)

1. A photocurable pressure-sensitive adhesive sheet comprising a pressure-sensitive adhesive layer cured by irradiation with radiation,

The adhesive layer may comprise a colorant and,

the maximum value of the transmittance of the adhesive layer at a wavelength of 200 to 400nm is larger than the maximum value of the transmittance at a wavelength of 400 to 700nm,

the storage modulus (G' b 85) of the adhesive layer before curing at 85 ℃ is lower than 65kPa,

the storage modulus (G 'a 10) of the adhesive layer after curing at 10 ℃ and the storage modulus (G' b 85) of the adhesive layer before curing at 85 ℃ satisfy the following relational expression (1),

3.3<G'a10/G'b85 (1)。

2. the photocurable adhesive sheet according to claim 1, wherein the colorant is a colorant having a maximum value of transmittance at a wavelength of 200 to 400nm that is greater than a maximum value of transmittance at a wavelength of 400 to 700 nm.

3. The photocurable adhesive sheet according to claim 1 or 2, wherein the curing based on irradiation with radiation is based on a cumulative light amount of 3000mJ/cm ² Is cured by ultraviolet irradiation.

4. The photocurable adhesive sheet according to any one of claims 1-3, wherein the cured adhesive layer has a storage modulus (G' a 10) of 90kPa or more at 10 ℃.

5. The photocurable adhesive sheet according to any one of claims 1-4, wherein the adhesive layer contains a base polymer, a crosslinking agent, and a photopolymerization initiator.

6. The photocurable adhesive sheet according to claim 5, wherein the base polymer contains an acrylic polymer.

7. The photocurable adhesive sheet according to claim 5 or 6, wherein the crosslinking agent contains a polyfunctional (meth) acrylate.

8. The photocurable adhesive sheet according to any one of claims 5-7, wherein the adhesive layer is a single layer formed from the base polymer having 2 opposing major faces,

when the single adhesive layer is divided into two parts in the thickness direction,

The concentration of the crosslinking agent and/or the photopolymerization initiator in one of the 2 main faces, that is, the region to which the 1 st main face belongs, is different from the concentration of the crosslinking agent and/or the photopolymerization initiator in the other one, that is, the region to which the 2 nd main face belongs.

9. The photocurable adhesive sheet according to claim 8, wherein the adhesive layer of the single layer has a concentration gradient of the crosslinking agent and/or the photopolymerization initiator in a thickness direction.

10. A method for producing the photocurable adhesive sheet according to claim 8 or 9, comprising the steps of:

an adhesive layer forming a single layer formed of the base polymer,

The layer of adhesive is allowed to cure,

preparing a solution of the crosslinking agent and/or the photopolymerization initiator,

applying the solution to one side of the cured adhesive layer, allowing the crosslinking agent and/or the photopolymerization initiator contained in the solution to penetrate from the one side of the adhesive layer in the thickness direction,

the adhesive layer is dried.

11. The photocurable adhesive sheet according to any one of claims 1-4, wherein the adhesive layer comprises a polymer having a benzophenone structure in a side chain.

12. The photocurable adhesive sheet according to claim 11, wherein the adhesive layer is a cured product of an adhesive composition containing an ethylenically unsaturated compound and a polymer having a benzophenone structure in a side chain.

13. A self-luminous display device, comprising:

display panel having a plurality of light emitting elements arranged on one surface of substrate, and method for manufacturing the same

The photocurable adhesive sheet according to any one of claim 1-9, 11 and 12,

the light emitting element of the display panel is sealed by the adhesive layer of the photocurable adhesive sheet,

the adhesive layer is cured.

14. The self-luminous display device according to claim 13, wherein the display panel is an LED panel in which a plurality of LED chips are arranged on one side of a substrate.

15. A method of manufacturing the self-luminous display device according to claim 13 or 14, comprising the steps of:

laminating the adhesive layer of the photocurable adhesive sheet according to any one of claims 1 to 9, 11 and 12 on a display panel having a plurality of light-emitting elements arranged on one surface of a substrate, and sealing the light-emitting elements with the adhesive layer; and

and a step of curing the adhesive layer by irradiation with radiation.

16. The method of manufacturing according to claim 15, wherein the radiation is ultraviolet.

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