CN115989143A - Adhesive composition, photocurable adhesive layer and photocurable adhesive sheet - Google Patents

Abstract

The purpose of the present invention is to provide an adhesive composition, an adhesive layer, and an adhesive sheet that are suitable for manufacturing a self-light-emitting display device such as a mini/micro LED display device having an improved contrast and a function of preventing reflection of metal wiring or the like, and that have both excellent level difference absorption properties and excellent processability. The present invention provides: an adhesive composition which comprises a colorant and a partial polymer of a polymer (A) having a benzophenone structure in a side chain, or a mixture of monomer components constituting the polymer (A) having a benzophenone structure in a side chain, and which has a maximum value of transmittance at a wavelength of 200 to 400nm which is larger than a maximum value of transmittance at a wavelength of 400 to 700 nm; a photocurable adhesive layer formed from a cured product of the adhesive composition, wherein the cured product is a cured product in which a benzophenone structure possessed by the polymer (a) having a benzophenone structure in a side chain remains; a photocurable adhesive sheet has the photocurable adhesive layer.

Description

Adhesive composition, photocurable adhesive layer and photocurable adhesive sheet

technical field

The present invention relates to an adhesive composition, a photocurable adhesive layer, and a photocurable adhesive sheet. More specifically, it relates to an adhesive composition, a photocurable adhesive layer, and a photocurable 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. As for 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, for example, when the mixed binder is colored black by mixing carbon black or the like, light cannot pass through the binder, so that curing is inhibited, making it difficult to improve workability.

The present invention has been made based on the above-mentioned situation, and the object of the present invention is to provide a self-luminous display device such as a mini/micro LED display device, which is suitable for manufacturing anti-reflection functions such as metal wirings, and a contrast ratio. An adhesive composition, an adhesive layer, and an adhesive sheet having both excellent height difference absorbency 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 by making the adhesive composition, photocurable adhesive layer, and photocurable adhesive sheet exhibit absorption in the visible light region, but in the visible light region It is colored so as to have high transmittance in the ultraviolet region, exhibits high light-shielding properties against visible light, and can be cured by ultraviolet irradiation. In addition, it was found that, as the above-mentioned adhesive composition, by using a polymer having a benzophenone structure in a side chain, a mixture of monomer components constituting the polymer, or a mixture of monomer components constituting the polymer The adhesive composition of a partial polymer can provide a photocurable adhesive layer and a photocurable adhesive sheet that can achieve both excellent height difference absorption before photocuring and excellent processability after photocuring, and self-luminescence In a type 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.

The first aspect of the present invention provides an adhesive composition containing a colorant and a polymer (A) having a benzophenone structure in a side chain, wherein the adhesive composition has a wavelength of 200 to 400 nm. The maximum value of the transmittance is greater than the maximum value of the transmittance at a wavelength of 400 to 700 nm.

In addition, a second aspect of the present invention provides an adhesive composition comprising a colorant and a mixture of monomer components constituting a polymer (A) having a benzophenone structure in a side chain or A partial polymer of a mixture of monomer components of the polymer (A) having a benzophenone structure, wherein the maximum value of the transmittance of the adhesive composition at a wavelength of 200 to 400 nm is greater than that at a wavelength of 400 to 700 nm Maximum transmittance. The adhesive composition of the 1st aspect and the 2nd aspect of this invention may contain an ethylenic unsaturated compound (B) further.

In this specification, the adhesive composition of the 1st and 2nd aspect of this invention may be collectively called "adhesive composition (A)".

In addition, in this specification, when referring to "a polymer (A) having a benzophenone structure in a side chain" or "BP polymer (A)", unless otherwise specified, it includes "a polymer having a benzophenone structure in a side chain". Polymer (A) having a ketone structure" and "a mixture of monomer components constituting the polymer (A) having a benzophenone structure in the side chain or a polymer (A) having a benzophenone structure in the side chain ) is a partial polymer of a mixture of monomer components".

In addition, the third aspect of the present invention provides a photocurable adhesive layer formed of a cured product of the adhesive composition (A) in which the diphenylbenzene Cured product of ketone structure. Moreover, the 4th aspect of this invention provides the photocurable adhesive sheet which has the photocurable adhesive layer of the 3rd aspect of this invention.

In this specification, the photocurable adhesive layer of the 3rd side of this invention may be called "photocurable adhesive layer (A)". Moreover, the photocurable adhesive sheet of the 4th aspect of this invention may be called "photocurable adhesive sheet (A)".

The photocurable adhesive layer (A) is formed from a cured product of the adhesive composition (A) in which the benzophenone structure of the BP polymer (A) remains. The benzophenone structure can be cured by forming a crosslinked structure by ultraviolet irradiation. The photocurable pressure-sensitive adhesive layer (A) before curing is in a highly fluid semi-cured state, and exhibits excellent height difference absorption. Therefore, when the photocurable adhesive layer (A) before curing is bonded to a display panel in which light-emitting elements (LED chips) are arranged at a high density, it can fully follow the fine level difference between the light-emitting elements (LED chips). , so that no air bubbles remain and there is no gap. On the other hand, the cured photocurable pressure-sensitive adhesive layer (A) exhibits excellent workability. Therefore, it is possible to suppress the occurrence of gaps when cutting the laminate including the cured photocurable adhesive layer (A), and to suppress the occurrence of protruding and sagging of the adhesive layer from the edge during storage. Thus, according to the photocurable adhesive layer (A) which consists of the said hardened|cured material of an adhesive composition (A), excellent level difference absorption and processability can be compatible suitably.

The maximum value of the transmittance in the wavelength 200-400nm of the adhesive composition (A) is larger than the maximum value of the transmittance in the wavelength 400-700nm. Moreover, it is preferable that the maximum value of the transmittance in the wavelength 200-400nm of the photocurable adhesive layer (A) is larger than the maximum value of the transmittance in the wavelength 400-700nm. That is, the pressure-sensitive adhesive composition (A) and the photocurable pressure-sensitive adhesive layer (A) have high absorptivity to visible light (wavelength: 400 to 700 nm), and are excellent in light-shielding properties. The constitution that the adhesive composition (A) and the photocurable adhesive layer (A) are excellent in light-shielding properties against visible light is preferable from the viewpoint of filling the fine height differences between LED chips without gaps The photocurable adhesive layer (A) prevents reflection due to metal wiring on the display panel, etc., prevents color mixing between arrayed light emitting elements (LED chips), and improves contrast. On the other hand, the pressure-sensitive adhesive composition (A) and the photocurable pressure-sensitive adhesive layer (A) have high permeability to ultraviolet light (wavelength: 200 to 400 nm). The adhesive composition (A) and the photocurable adhesive layer (A) have excellent transmittance to ultraviolet rays from the fact that the curing reaction proceeds by irradiating the photocurable adhesive layer (A) with ultraviolet rays. It is preferable at the point which the workability of a curable pressure-sensitive adhesive layer (A) improves. That is, the maximum value of the transmittance of the adhesive composition (A) and the photocurable adhesive layer (A) at a wavelength of 200 to 400 nm is greater than the maximum value of the transmittance of the wavelength of 400 to 700 nm. It is preferable at the point which can balance the excellent light-shielding with respect to visible light, and the hardening reaction by ultraviolet-ray irradiation.

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. In this constitution, 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 of the adhesive composition (A) and the photocurable adhesive layer (A). On the one hand, it is preferable.

In this specification, "the coloring agent whose maximum value of the transmittance in wavelength 200-400nm is larger than the maximum value of the transmittance in wavelength 400-700nm" may be called "coloring agent (A)".

It is preferable that the adhesive composition (A) further contains the photoinitiator (C) which absorbs the ultraviolet-ray of wavelength 300nm-500nm, and generates a radical. This configuration is preferable to obtain a photocurable adhesive layer (A) by curing the adhesive composition (A) into a cured product in which the benzophenone structure of the BP polymer (A) remains. of.

It is preferable that the storage elastic modulus (G'b85) at 85 degreeC of the photocurable adhesive layer (A) before hardening is less than 65 kPa. This configuration is preferable because the photocurable pressure-sensitive adhesive layer (A) before curing exhibits excellent step absorption.

Preferably, the storage modulus (G'a10) of the photocurable adhesive layer (A) after curing at 10°C is the same as the storage modulus at 85°C of the photocurable adhesive layer (A) before curing. The quantity (G'b85) satisfies the following relational expression (1).

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

This configuration is preferable in that the photocurable pressure-sensitive adhesive layer (A) before curing exhibits excellent level difference absorption and the photocurable pressure-sensitive adhesive layer (A) after curing exhibits excellent processability.

It is preferable that the storage elastic modulus (G'a10) at 10 degreeC of the said photocurable adhesive layer (A) after hardening is 90 kPa or more. This configuration is preferable from the viewpoint that the cured photocurable pressure-sensitive adhesive layer (A) exhibits excellent workability.

The above-mentioned curing is preferably curing by ultraviolet irradiation with a wavelength of less than 300 nm and an accumulated light quantity of 3000 mJ/cm ² . This configuration is preferable in that the photocurable adhesive layer (A) forms and cures the benzophenone structure into a crosslinked structure by the ultraviolet irradiation, and exhibits excellent processability.

In addition, a fifth 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; the aforementioned photocurable adhesive sheet (A); The light-emitting element of is sealed by the photocurable adhesive layer (A) of the aforementioned photocurable adhesive sheet (A), and the aforementioned photocurable adhesive layer (A) is cured. In the self-luminous display device according to the fifth 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, in the self-luminous display device of the fifth aspect of the present invention, the photocurable adhesive is filled without gaps in the fine level difference between the light-emitting elements (LED chips). The layer (A) can prevent reflection of metal wiring etc. on the substrate, prevent RGB color mixing, and improve contrast.

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

The photocurable adhesive layer (A) of the photocurable adhesive sheet (A) is laminated on the display panel in which a plurality of light emitting elements are arranged on one side of the substrate, and the photocurable adhesive layer (A) is used for the aforementioned The process of sealing the light-emitting element; and

The process of hardening by irradiating ultraviolet-ray to the said photocurable adhesive layer (A).

Since the photocurable pressure-sensitive adhesive layer (A) before curing has excellent level difference absorbability, it fully follows the minute level difference between the light-emitting elements and adheres without remaining air bubbles and without gaps. Moreover, it hardens|cures by irradiating ultraviolet-ray to the said photocurable adhesive layer (A), and it is excellent in workability.

In the method of manufacturing a self-luminous display device according to the fifth aspect of the present invention, the ultraviolet rays are preferably ultraviolet rays having a wavelength of less than 300 nm. This configuration is preferable from the viewpoint that the photocurable pressure-sensitive adhesive layer (A) forms a crosslinked structure of the benzophenone structure by ultraviolet irradiation and is cured, thereby exhibiting excellent processability.

The effect of the invention

The adhesive composition, photocurable adhesive layer, and photocurable adhesive sheet of the present invention have high light-shielding properties for visible light and excellent level difference absorption, so they are used in the manufacture of self-luminous display devices, thereby eliminating Gap fills the height difference between multiple light emitting elements, prevents reflection from metal wiring, suppresses color mixing between multiple light emitting elements, and improves contrast. In addition, it can be cured by ultraviolet irradiation to improve processability, suppress the occurrence of gaps during cutting, and suppress the occurrence of protruding and sagging of the adhesive layer from the edge during storage. Therefore, by using the adhesive composition, photocurable adhesive layer, and photocurable adhesive sheet of the present invention for the manufacture of a self-luminous display device, it is possible to efficiently produce a function of improving the reflection prevention of metal wiring and the like. 1. A self-luminous display device with 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 one embodiment of the 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.

In this specification, "acrylic polymer" refers to a polymer derived from a monomer component containing more than 50% by weight of acrylic monomers (preferably more than 70% by weight, for example, more than 90% by weight). The above-mentioned acrylic monomer refers to a monomer derived from a monomer having at least one (meth)acryloyl group in one molecule. In addition, in this specification, a "(meth)acryloyl group" is a generic term for an acryloyl group and a methacryloyl group. Likewise, "(meth)acrylate" is a generic term for acrylate and methacrylate, and "(meth)acrylic acid" is a generic term for acrylic acid and methacrylic acid.

In this specification, an "ethylenically unsaturated compound" means a compound having at least one ethylenically unsaturated group in a molecule. Examples of ethylenically unsaturated groups include (meth)acryloyl groups, vinyl groups, allyl groups, and the like. Hereinafter, a compound having one ethylenically unsaturated group may be referred to as a "monofunctional monomer", and a compound having two or more ethylenically unsaturated groups may be referred to as a "polyfunctional monomer". Moreover, among polyfunctional monomers, the compound which has X ethylenic unsaturated groups may be described as "X functional monomer."

In this specification, unless the adhesive composition contains an ethylenic unsaturated compound in particular, it means containing the said ethylenic unsaturated compound in the form of a partial polymer. Such a partial polymer is usually a mixture of the above-mentioned ethylenically unsaturated compound (unreacted monomer) in which the ethylenically unsaturated group is not reacted and the above-mentioned ethylenically unsaturated compound in which the ethylenically unsaturated group is polymerized.

In this specification, all the monomer components constituting the adhesive composition refer to the monomer components constituting the polymer contained in the adhesive composition and those contained in the adhesive composition in the form of unreacted monomers. The total amount of monomer components. The composition of the monomer components constituting the adhesive composition is generally the same as the composition of the monomer components of the adhesive layer formed from the adhesive composition and the composition of the monomer components constituting its photocured product.

In this specification, "active energy ray" is a concept including light such as ultraviolet rays, visible light, and infrared rays, α-rays, β-rays, γ-rays, electron rays, neutron rays, and radiation rays such as X-rays.

[Adhesive composition (A)]

The adhesive composition of the first aspect of the present invention contains a colorant and a polymer (A) having a benzophenone structure in a side chain, and the transmittance at a wavelength of 200 to 400 nm of the adhesive composition is The maximum value is greater than the maximum value of the transmittance at a wavelength of 400 to 700 nm.

In addition, the adhesive composition of the second aspect of the present invention contains a colorant and a mixture of monomer components constituting the polymer (A) having a benzophenone structure in the side chain, or comprises a polymer (A) having a benzophenone structure in the side chain. A partial polymer of a mixture of monomer components of the ketone-structured polymer (A), wherein the maximum value of the transmittance of the adhesive composition at a wavelength of 200 to 400 nm is greater than that of the transmittance at a wavelength of 400 to 700 nm maximum value.

The adhesive composition (adhesive composition (A)) of the 1st and 2nd aspect of this invention may contain an ethylenic unsaturated compound (B) further.

The adhesive composition (A) may contain the photoinitiator (C) which absorbs the ultraviolet-ray of wavelength 300nm-500nm mentioned later and generates a radical other than the above, and other additives.

In addition, in this specification, the said "mixture of monomer components" includes the case where it consists of a single monomer component, and the case where it consists of 2 or more types of monomer components. In addition, the above "partial polymer of a mixture of monomer components" refers to a composition in which one or more monomer components constituting the "mixture of monomer components" are partially polymerized.

The adhesive composition (A) may have any form, for example, solvent type, emulsion type, heat-melt type (hot-melt type), solvent-free type (active energy ray curing type, such as monomer mixture, or monomer Mixtures and their partial polymers, etc.) etc. From the viewpoint of obtaining an adhesive layer excellent in appearance, the adhesive composition (A) of the present invention is preferably an active energy ray-curable type. In this specification, an adhesive composition refers to a composition for forming an adhesive layer, including a composition for forming an adhesive.

The adhesive composition (A) is not particularly limited, and examples include: a composition containing BP polymer (A) as an essential component; a mixture of monomer components constituting BP polymer (A) or a part thereof Compositions in which polymers are an essential component, etc. Although not particularly limited, examples of the former include so-called solvent-based adhesive compositions, water-dispersed adhesive compositions (emulsion adhesive compositions), and the like, and examples of the latter include so-called active energy ray-curable adhesive composition, etc.

The adhesive composition (A) may be a solvent type as described above. The solvent is not particularly limited as long as it is an organic compound that can be used as a solvent. For example, hydrocarbon solvents such as cyclohexane, hexane, and heptane; aromatic solvents such as toluene and xylene; ethyl acetate , methyl acetate and other ester-based solvents; acetone, methyl ethyl ketone and other ketone-based solvents; methanol, ethanol, butanol, isopropanol and other alcohol-based solvents, etc. In addition, the above-mentioned solvent may be a mixed solvent containing two or more solvents.

The adhesive composition (A) may be an acrylic acid containing acrylic monomers in an amount 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. An adhesive composition.

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

The adhesive composition (A) has low transmittance to visible light (wavelength 400 to 700 nm), that is, high light-shielding property. The photocurable adhesive layer (A) formed from the cured product of the adhesive composition (A) excellent in light-shielding properties against visible light is passed through the self-luminous display device (mini/micro LED display device) without gaps. The fine level difference between the metal wiring layer and the light emitting element (LED chip) is sealed, thereby preventing reflection caused by metal wiring, etc., preventing color mixing of the light emitting element (LED chip), and improving image contrast.

On the other hand, the adhesive composition (A) has higher transmittance in the ultraviolet region (wavelength 200 to 400 nm, preferably wavelength 330 to 400 nm) than visible light. Therefore, the photocurable pressure-sensitive adhesive layer (A) formed from the cured product of the pressure-sensitive adhesive composition (A) can be cured by forming a crosslinked structure of the benzophenone structure by ultraviolet irradiation. The processability of the photocurable adhesive layer (A) hardened|cured by ultraviolet irradiation improves, and the adhesive gap at the time of cutting processing, and the overflow and sagging of the adhesive layer from the edge part at the time of storage can be suppressed.

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 composition (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, in a preferred embodiment of the present invention, the average transmittance at a wavelength of 200 to 400 nm (preferably at a wavelength of 330 to 400 nm) of the adhesive composition (A) is greater than the average transmittance at a wavelength of 400 to 700 nm. . The average transmittance of the adhesive composition (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 , less than 20%, less than 10% or less than 5%.

[Colorant]

The adhesive composition (A) contains a colorant. The coloring agent is not particularly limited, but is preferably a coloring agent whose maximum transmittance at a wavelength of 200 to 400 nm (preferably at a wavelength of 330 to 400 nm) is greater than the maximum value of the transmittance at a wavelength of 400 to 700 nm (coloring agent (A )).

The maximum value of the transmittance at a wavelength of 200 to 400 nm (preferably a wavelength of 330 to 400 nm) of the adhesive composition (A) is not particularly limited, and may be greater than the maximum value of the transmittance at a wavelength of 400 to 700 nm. It is preferably achieved by making the adhesive composition (A) contain the colorant (A).

When the adhesive composition (A) contains the colorant (A), the transmittance to visible light (wavelength 400 to 700 nm) is reduced, that is, the light-shielding property is improved. On the other hand, compared with visible light, the ultraviolet region (wavelength 200 to 400 nm, preferably a wavelength of 330 to 400 nm), the transmittance becomes high.

The maximum value of the transmittance of the colorant (A) at a wavelength of 400 to 700 nm (visible light region) may be, for example, 80% or less, 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, in a preferred embodiment of the present invention, the colorant (A) has an average transmittance at a wavelength of 200 to 400 nm (preferably at 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 (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.

For the transmittance of the coloring agent, it is possible to use an appropriate solvent such as tetrahydrofuran (THF) or a dispersion medium (an organic material having a small absorption in the wavelength range of 200 to 700 nm) so that the transmittance at a wavelength of 400 nm is about 50 to 60%. Solvent) diluted solution or dispersion for measurement.

The coloring agent may be a dye or a pigment as long as it can be dissolved or dispersed in the adhesive composition (A). 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 in the adhesive composition (A) is, for example, about 0.01 to 20 parts by weight, preferably 0.1 to 10 parts by weight, based on 100 parts by weight of the adhesive composition (A). The color tone, light transmittance, etc. of a photocurable adhesive layer (A) should just be set suitably. The coloring agent can also be added in the form of a solution or dispersion liquid dissolved or dispersed in an appropriate solvent.

[Polymer (A) having a benzophenone structure in a side chain]

The polymer (A) (BP polymer (A)) which has a benzophenone structure in a side chain is contained as a base polymer which comprises the adhesive composition (A) of this invention. That is, the adhesive composition (A) of this invention is an adhesive composition containing BP polymer (A) as a base polymer. In addition, BP polymer (A) can be used individually or in combination of 2 or more types.

As a monomer component that can constitute the BP polymer (A), a compound having an ethylenically unsaturated group and a benzophenone structure in the molecule (hereinafter sometimes referred to as "ethylenically unsaturated BP") is included, and further Ethylenically unsaturated compounds (hereinafter may be referred to as "other ethylenically unsaturated compounds.") which do not belong to ethylenically unsaturated BP are included.

As a suitable example of a BP polymer (A), an acrylic polymer which has a benzophenone structure in a side chain is mentioned. It is preferable that the said BP polymer (A) 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 photocurable adhesive layer (A) formed from the hardened|cured material of the said adhesive composition (A) containing a BP polymer (A) may contain a benzophenone structure. When this benzophenone structure is excited by ultraviolet irradiation, it can form a crosslinked structure by the abstraction reaction of a hydrogen radical, and can harden a photocurable adhesive layer (A).

As the above-mentioned BP polymer (A), 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 a phenyl group optionally having a substituent A phenylene polymer having a benzophenone structure in a side chain. 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 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 (A) may have a side chain in which the above-mentioned benzophenone structure is directly bonded to the main chain, or may have a side chain that is bonded by one or more of ester bonds, oxyalkylene structures, etc., for example. Side chains bonded to the main chain. A suitable example of the BP polymer (A) includes a polymer containing a repeating unit derived from ethylenically unsaturated BP. 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 individually by 1 type or in combination of 2 or more types for preparation of BP polymer (A). 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 (A) may be a copolymer having repeating units derived from ethylenically unsaturated BP and repeating units derived from ethylenically unsaturated compounds (other ethylenically unsaturated compounds) not belonging to ethylenically unsaturated BP . Such a BP polymer (A) may be a copolymer comprising monomer components of the above-mentioned ethylenically unsaturated BP and the above-mentioned other ethylenically unsaturated compound. 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. As a suitable example of the BP polymer (A), 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 (A) is acrylic acid. Acrylic BP polymer based on monomer.

The monomer component constituting the BP polymer (A) may contain one or two or more selected from alkyl (meth)acrylates having an alkyl group at an ester terminal as the above-mentioned other ethylenically unsaturated compounds. Hereinafter, an alkyl (meth)acrylate having a linear or branched alkyl group having a carbon number of X or more and Y or less at an ester end may be referred to as "C _XY alkyl (meth)acrylate" . The monomer components constituting the BP polymer (A) preferably include at least C _1-20 alkyl (meth)acrylate as the above-mentioned other monomers, more preferably C _4-20 alkyl (meth)acrylate, and further preferably Contains C _4-18 alkyl (meth)acrylates (eg C _4-9 alkyl acrylates).

As non-limiting specific examples of C _1-20 alkyl (meth)acrylates, methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, (meth) Isopropyl acrylate, n-butyl (meth)acrylate, isobutyl (meth)acrylate, sec-butyl (meth)acrylate, tert-butyl (meth)acrylate, amyl (meth)acrylate, ( Isoamyl methacrylate, Hexyl (meth)acrylate, Heptyl (meth)acrylate, Octyl (meth)acrylate, 2-Ethylhexyl (meth)acrylate, Iso(meth)acrylate Octyl, nonyl (meth)acrylate, isononyl (meth)acrylate, decyl (meth)acrylate, isodecyl (meth)acrylate, undecyl (meth)acrylate, (meth)acrylate base) dodecyl acrylate, tridecyl (meth)acrylate, tetradecyl (meth)acrylate, pentadecyl (meth)acrylate, hexadecyl (meth)acrylate Heptadecyl (meth)acrylate, Stearyl (meth)acrylate, Isostearyl (meth)acrylate, Nonadecyl (meth)acrylate, Dinonadecyl (meth)acrylate Decyl esters, etc. As a particularly preferable alkyl (meth)acrylate, n-butyl acrylate (BA), 2-ethylhexyl acrylate (2EHA), isononyl acrylate, etc. are mentioned. Other specific examples of alkyl (meth)acrylates that can be preferably used include n-butyl methacrylate (BMA), 2-ethylhexyl methacrylate (2EHMA), isostearyl acrylate ( iSTA) and so on. Alkyl (meth)acrylate can be used individually by 1 type or in combination of 2 or more types. The monomer component constituting the BP polymer (A) may contain one or two or more selected from the copolymerizable monomers described later as the above-mentioned other ethylenically unsaturated compounds.

The aforementioned adhesive composition (A) may be a photocurable acrylic monomer in which more than 50% by weight (preferably more than 70% by weight, for example, more 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 (A) 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 photocurable adhesive layer (A) and the handleability of the photocurable adhesive sheet (A), it is appropriate that the Mw of the BP polymer (A) is usually 1×10 ⁴ or more. It is preferably 5×10 ⁴ or more, may be 10×10 ⁴ or more, may be 15×10 ⁴ or more, and may be 20×10 ⁴ or more. In addition, from the viewpoint of the height difference absorption of the photocurable adhesive layer (A), the Mw of the BP polymer (A) is generally 200×10 ⁴ or less, preferably 150×10 ⁴ or less, and may be It is 100×10 ⁴ or less, may be 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 (A) is not particularly limited. The Tg of the BP polymer (A) 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 height difference absorption of the photocurable adhesive layer (A), it is appropriate that the Tg of the BP polymer (A) is lower than 0°C, preferably -10°C or lower, may be -20°C or lower, It may be -30°C or lower, -40°C or lower, or -50°C or lower. In addition, from the viewpoint of the cohesiveness of the photocurable adhesive layer (A) and the processability improvement after photocuring, it is generally advantageous that the Tg of the BP polymer (A) is -75° C. or higher, and may be Above -70°C. In some embodiments, the Tg of the BP polymer (A) may be -55°C or higher, or -45°C or higher. The Tg of the BP polymer (A) 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 (A) 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 that the BP equivalent of the BP polymer (A) is usually 0.1 mg/g or more, 0.5 mg/g or more, 1 mg/g or more, 5 mg/g or more, 8 mg/g or more, 10 mg/g or more, 15 mg/g or more, or 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 (A) is generally 100 mg/g or less, and may be 80 mg/g. g or less, may be 60 mg/g or less, may be 40 mg/g or less, may be 25 mg/g or less, or may be 15 mg/g or less. The BP equivalent of the BP polymer (A) can be adjusted by the composition of the monomer components constituting the BP polymer (A).

In addition, from the standpoint of reducing the peeling force by photocuring, performing 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 (A) in the adhesive composition (A) as a whole, that is, the weight fraction of the BP polymer in the adhesive composition (A), is not particularly limited, and can be used as a photocurable adhesive The level difference absorption of the mixture layer (A) is set so that the workability of its photocured product can be properly balanced. In some embodiments, the weight fraction of the above-mentioned BP polymer (A) 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, may be It may be 25% by weight or more, may be 35% by weight or more, may be 45% by weight or more, and may be 55% by weight or more. When the weight fraction of the BP polymer (A) increases, G'a10/G'b85 described later tends to increase.

It may also implement so that the weight fraction of the BP polymer (A) in an adhesive composition (A) may be substantially 100 weight% (for example, 99.5 weight% or more). In addition, from the viewpoint of the ease of adhesion, in some embodiments, the weight fraction of the BP polymer (A) in the adhesive composition (A) may be lower than 99% by weight, may be lower than 95% by weight %, may be lower than 85% by weight, may be lower than 70% by weight, may be lower than 50% by weight, or may be lower than 40% by weight.

It is preferable to contain, for example, about 0.1 mg or more of the benzophenone structure per 1 g of the adhesive composition (A) in terms of 4-benzoylphenyl acrylate. Hereinafter, the weight in terms of 4-benzoylphenyl acrylate of the benzophenone structure contained per 1 g of the adhesive composition (A) may be referred to as the BP equivalent of the adhesive 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 adhesive composition is generally 0.3 mg/g or more, which can 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, may be 20 mg/g or more. In addition, in some embodiments, from the viewpoint of the impact resistance of the joint portion by the photocured product and the suppression of strain in the photocured product, it is appropriate that the BP equivalent of the adhesive composition is generally 100 mg/g or less, 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.

[Ethylenically unsaturated compound (B)]

The adhesive composition (A) may further contain an ethylenically unsaturated compound (B) in addition to the BP polymer (A). When the adhesive composition (A) is a solventless type (active energy ray curing type) adhesive composition, it is preferable that the adhesive composition (A) contains an ethylenic unsaturated compound (B). On the other hand, when the PSA composition (A) is a solvent-type or emulsion-type PSA composition, the ethylenically unsaturated compound (B) may not be contained.

In addition, when the adhesive composition (A) contains a mixture of monomer components constituting the BP polymer (A) or a partial polymer of a mixture of monomer components constituting the BP polymer (A), the above-mentioned Since other ethylenically unsaturated compounds are used as the monomer component, it is not necessary to include the ethylenically unsaturated compound (B). When the adhesive composition (A) comprising the mixture of the monomer components or a partial polymer thereof contains an ethylenically unsaturated compound (B), the ethylenically unsaturated compound (B) may be the same as the above-mentioned other ethylenically unsaturated compound , can also be different.

Examples of the compound usable as the ethylenically unsaturated compound (B) include the aforementioned alkyl (meth)acrylate and the aforementioned ethylenically unsaturated BP. Among these, it is preferable to use at least alkyl (meth)acrylate (such as C _1-20 alkyl (meth)acrylate, more preferably C _4-18 alkyl (meth)acrylate, further preferably acrylic acid C _4-9 alkyl esters). Examples of particularly preferable alkyl (meth)acrylates include n-butyl acrylate (BA) and 2-ethylhexyl acrylate (2EHA). Other specific examples of alkyl (meth)acrylates that can be preferably used include isononyl acrylate, n-butyl methacrylate (BMA), 2-ethylhexyl methacrylate (2EHMA), acrylic acid Isostearyl ester (iSTA), etc. Alkyl (meth)acrylate can be used individually by 1 type or in combination of 2 or more types. In some embodiments, the ethylenically unsaturated compound (B) preferably contains either or both of n-butyl acrylate (BA) and 2-ethylhexyl acrylate (2EHA), more preferably at least BA.

The ethylenically unsaturated compound (B) may contain a C _4-9 alkyl acrylate in a ratio of 40% by weight or more. The ratio of the C _4-9 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 cohesiveness of the photocurable adhesive layer (A), the ratio of the _C4-9 alkyl acrylate to the ethylenically unsaturated compound (B) is usually 99.5% by weight. The following is suitable, and may be 95% by weight or less, 85% by weight or less, 70% by weight or less, or 60% by weight or less.

As another example of the compound which can be used as an ethylenic unsaturated compound (B), the ethylenic unsaturated compound (copolymerizable monomer) copolymerizable with an alkyl (meth)acrylate is mentioned. As the copolymerizable monomer, a monomer having a polar group (for example, a carboxyl group, a hydroxyl group, a ring containing a nitrogen atom, etc.) can be suitably used. A monomer having a polar group, for example, contributes to the introduction of a crosslinking point into a polymer containing a repeating unit derived from the monomer, or improves the cohesion of the photocurable pressure-sensitive adhesive layer (A). A copolymerizable monomer can be used individually by 1 type or in combination of 2 or more types.

The following are mentioned as a non-limiting specific example of a copolymerizable monomer.

Carboxyl group-containing monomers: for example, acrylic acid, methacrylic acid, carboxyethyl acrylate, carboxypentyl acrylate, itaconic acid, maleic acid, fumaric acid, crotonic acid, isocrotonic acid, and the like.

Anhydride group-containing monomers: such as maleic anhydride and itaconic anhydride.

Hydroxyl-containing monomers: such as 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, 4-Hydroxybutyl (meth)acrylate, 6-Hydroxyhexyl (meth)acrylate, 8-Hydroxyoctyl (meth)acrylate, 10-Hydroxydecyl (meth)acrylate, 12 (meth)acrylate -Hydroxylauryl (meth)acrylate, hydroxyalkyl (meth)acrylate, such as (4-hydroxymethylcyclohexyl) methyl (meth)acrylate, etc.

Monomers containing sulfonic acid or phosphoric acid groups: e.g. styrenesulfonic acid, allylsulfonic acid, sodium vinylsulfonate, 2-(meth)acrylamide-2-methylpropanesulfonic acid, (methyl) Acrylamidopropanesulfonic acid, sulfopropyl (meth)acrylate, (meth)acryloyloxynaphthalenesulfonic acid, 2-hydroxyethylacryloyl phosphate, etc.

Epoxy-containing monomers: such as (meth)acrylic acid glycidyl ester, (meth)acrylic acid-2-ethyl glycidyl ether and other epoxy-containing acrylates, allyl glycidyl ether, (methyl) Glycidyl acrylate, etc.

Cyano-containing monomers: such as acrylonitrile, methacrylonitrile, etc.

Isocyanate group-containing monomers: for example, 2-(meth)acryloyloxyethyl isocyanate, (meth)acryloyl isocyanate, m-isopropenyl-α,α-dimethylbenzyl isocyanate and the like.

Amide-containing monomers: e.g. (meth)acrylamide; N,N-dimethyl(meth)acrylamide, N,N-diethyl(meth)acrylamide, N,N-dipropyl( Meth)acrylamide, N,N-diisopropyl (meth)acrylamide, N,N-di(n-butyl)(meth)acrylamide, N,N-di(tert-butyl)(meth)acrylamide base) acrylamide and other N,N-dialkyl (meth)acrylamide; N-ethyl (meth)acrylamide, N-isopropyl (meth)acrylamide, N-butyl (methyl) N-alkyl (meth)acrylamides such as acrylamide and N-n-butyl (meth)acrylamide; N-vinyl carboxylic acid amides such as N-vinylacetamide; monomers with hydroxyl and amide groups , such as N-(2-hydroxyethyl)(meth)acrylamide, N-(2-hydroxypropyl)(meth)acrylamide, N-(1-hydroxypropyl)(meth)acrylamide, N-(3-hydroxypropyl)(meth)acrylamide, N-(2-hydroxybutyl)(meth)acrylamide, N-(3-hydroxybutyl)(meth)acrylamide, N- (4-Hydroxybutyl)(meth)acrylamide and other N-hydroxyalkyl(meth)acrylamides; monomers with alkoxy and amide groups such as N-methoxymethyl(meth)acrylamide Amide, N-methoxyethyl (meth)acrylamide, N-butoxymethyl (meth)acrylamide and other N-alkoxyalkyl (meth)acrylamide; In addition, N,N- Dimethylaminopropyl (meth)acrylamide, N-(meth)acryloylmorpholine, and the like.

Amino group-containing monomers: eg, aminoethyl (meth)acrylate, N,N-dimethylaminoethyl (meth)acrylate, tert-butylaminoethyl (meth)acrylate. Monomers having epoxy groups: eg glycidyl (meth)acrylate, methylglycidyl (meth)acrylate, allyl glycidyl ether.

Monomers having rings containing nitrogen atoms: e.g. N-vinyl-2-pyrrolidone, N-methylvinylpyrrolidone, N-vinylpyridine, N-vinylpiperidone, N-vinylpyrimidine, N- Vinylpiperazine, N-vinylpyrazine, N-vinylpyrrole, N-vinylimidazole, N-vinyloxazole, N-(meth)acryloyl-2-pyrrolidone, N-(methyl) Acryloylpiperidine, N-(meth)acryloylpyrrolidine, N-vinylmorpholine, N-vinyl-3-morpholinone, N-vinyl-2-caprolactam, N-vinyl-1, 3-oxazin-2-one, N-vinyl-3,5-morpholinedione, N-vinylpyrazole, N-vinylisoxazole, N-vinylthiazole, N-vinylisothiazole , N-vinylpyridazine, etc. (for example, lactams such as N-vinyl-2-caprolactam).

Monomers having a succinimide skeleton: for example, N-(meth)acryloyloxymethylene succinimide, N-(meth)acryloyl-6-oxyhexamethylene succinimide, N-(meth)acryloyl-8-oxyhexamethylene succinimide and the like.

Maleimides: for example, N-cyclohexylmaleimide, N-isopropylmaleimide, N-laurylmaleimide, N-phenylmaleimide and the like.

Itaconimides: such as N-methyl itaconimide, N-ethyl itaconimide, N-butyl itaconimide, N-octyl itaconimide, N- 2-Ethylhexyl itaconimide, N-cyclohexyl itaconimide, N-lauryl itaconimide, etc.

Aminoalkyl (meth)acrylates: such as aminoethyl (meth)acrylate, N,N-dimethylaminoethyl (meth)acrylate, N,N-diethylamino (meth)acrylate Ethyl ester, tert-butylaminoethyl (meth)acrylate.

Alkoxy-containing monomers: e.g. 2-methoxyethyl (meth)acrylate, 3-methoxypropyl (meth)acrylate, 2-ethoxyethyl (meth)acrylate, (methyl) ) propoxyethyl acrylate, butoxyethyl (meth)acrylate, ethoxypropyl (meth)acrylate etc. alkoxyalkyl (meth)acrylate (alkoxyalkyl (methyl) ) Acrylates); (meth)acrylic acid such as methoxyethylene glycol (meth)acrylate, methoxypolyethylene glycol (meth)acrylate, methoxypolypropylene glycol (meth)acrylate, etc. Alkoxyalkylene glycol esters such as alkoxypolyalkylene glycol (meth)acrylates.

Alkoxysilyl-containing monomers: such as 3-(meth)acryloxypropyltrimethoxysilane, 3-(meth)acryloxypropyltriethoxysilane, 3-( Alkoxysilyl-containing (meth)acrylic acid such as meth)acryloxypropylmethyldimethoxysilane, 3-(meth)acryloxypropylmethyldiethoxysilane, etc. Alkoxysilyl-containing vinyl compounds such as esters, vinyltrimethoxysilane, vinyltriethoxysilane, etc.

Vinyl esters: such as vinyl acetate, vinyl propionate, etc.

Vinyl ethers: such as vinyl alkyl ethers such as methyl vinyl ether and ethyl vinyl ether.

Aromatic vinyl compounds: such as styrene, α-methylstyrene, vinyltoluene, etc.

Olefins: such as ethylene, butadiene, isoprene, isobutylene, etc.

(Meth)acrylates with alicyclic hydrocarbon groups: e.g. cyclopentyl (meth)acrylate, cyclohexyl (meth)acrylate, isobornyl (meth)acrylate, dicyclopentyl (meth)acrylate (meth)acrylates containing alicyclic hydrocarbon groups such as esters, adamantyl (meth)acrylates, etc.

(Meth)acrylates with aromatic hydrocarbon groups: (meth)acrylic acid containing aromatic hydrocarbon groups such as phenyl (meth)acrylate, phenoxyethyl (meth)acrylate, benzyl (meth)acrylate, etc. ester.

In addition, (meth)acrylates containing heterocycles such as tetrahydrofurfuryl (meth)acrylate, (meth)acrylates containing halogen atoms such as (meth)acrylates containing vinyl chloride and fluorine atoms, organic Silicon atom-containing (meth)acrylates such as silicon (meth)acrylates, (meth)acrylates obtained from terpene compound derivative alcohols, and the like.

When using such a copolymerizable monomer, the usage-amount is not specifically limited, Usually, it is suitable to set it as 0.01 weight% or more of all the monomer components which comprise an adhesive composition (A). From the point of view of better exerting the use effect of the copolymerizable monomer, the usage amount of the copolymerizable monomer (that is, the weight fraction of the copolymerizable monomer in the above-mentioned total monomer components) can be set as 0.1% of the total monomer components. % by weight or more, may be 0.5% by weight or more. In addition, from the viewpoint of easy balance of adhesive properties, the usage-amount of the copolymerizable monomer is generally 50% by weight or less of the total monomer components, preferably 40% by weight or less.

The above-mentioned copolymerizable monomer may contain a monomer having a nitrogen atom. By using the monomer which has a nitrogen atom, the cohesive force of a photocurable pressure-sensitive adhesive layer (A) can be improved, and the peeling strength after photocuring can be improved preferably. A suitable example of the monomer having a nitrogen atom includes a monomer having a nitrogen atom-containing ring. As the monomer having a nitrogen atom-containing ring, those exemplified above and the like can be used, 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). Among them, N-vinyl-2-pyrrolidone can be preferably used. (Meth)acrylamide is mentioned as another suitable example of the monomer which has a nitrogen atom.

The usage amount when using a monomer having a nitrogen atom (preferably a monomer having a ring containing a nitrogen atom such as N-vinyl cyclic amide) is not particularly limited, for example, it may be 1% by weight or more of the total monomer components, and may be It may be 2% by weight or more, may be 3% by weight or more, further may be 5% by weight or more, or may be 7% by weight or more. In one aspect, the usage-amount of the monomer containing a nitrogen atom may be 10 weight% or more of all monomer components, may be 15 weight% or more, and may be 20 weight% or more. 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 usage-amount of the monomer containing a nitrogen atom may be 20 weight% or less of the whole monomer component, for example, and may be 15 weight% or less. Alternatively, a nitrogen atom-containing monomer may not be used as the above-mentioned copolymerizable monomer.

The above-mentioned copolymerizable monomer may contain a hydroxyl group-containing monomer. By using a hydroxyl group-containing monomer, the cohesive force of a photocurable adhesive layer (A) and the degree of crosslinking (for example, the crosslinking by an isocyanate crosslinking agent) can be adjusted suitably. 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 photocurable adhesive layer (A) or its photocured product, 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. It is suitable, and may be 30 weight% or less, may be 25 weight% or less, and may be 20 weight% or less. In another embodiment, the usage-amount of a hydroxyl group containing monomer can be 15 weight% or less, 10 weight% or less, 5 weight% or less of the whole monomer component, for example. Alternatively, a hydroxyl group-containing monomer may not be used as the above-mentioned copolymerizable monomer.

The ratio of the carboxyl group-containing monomer to the total monomer components may 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). The adhesive composition (A) 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 on purpose. This may be advantageous from the viewpoint of the metal corrosion prevention properties of the photocurable adhesive layer (A) formed from the adhesive composition (A) and its photocured product.

The above-mentioned copolymerizable monomer may contain an alicyclic hydrocarbon group-containing (meth)acrylate. Thereby, the cohesive force of a photocurable adhesive layer (A) can be improved, and the peeling strength after photocuring can be improved. As the alicyclic hydrocarbon group-containing (meth)acrylate, those exemplified above and the like can be used, for example, cyclohexyl acrylate and isobornyl acrylate can be preferably used. The usage-amount when using an alicyclic hydrocarbon group containing (meth)acrylate 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 aspect, the usage-amount of the alicyclic hydrocarbon group containing (meth)acrylate may be 10 weight% or more of all monomer components, and may be 15 weight% or more. The upper limit of the amount of alicyclic hydrocarbon group-containing (meth)acrylate is about 40% by weight or less. For example, it may be 30% by weight or less, or 25% by weight or less (for example, 15% by weight or less, Furthermore, 10% by weight or less). Alternatively, an alicyclic hydrocarbon group-containing (meth)acrylate may not be used as the above-mentioned copolymerizable monomer.

The above-mentioned copolymerizable monomer may contain an alkoxysilyl group-containing monomer. The alkoxysilyl group-containing monomer is typically an ethylenically unsaturated compound having at least 1 (preferably 2 or more, such as 2 or 3) alkoxysilyl groups in one molecule, specifically Example as above. The aforementioned alkoxysilyl group-containing monomers may be used alone or in combination of two or more. By using an alkoxysilyl group-containing monomer, it is possible to introduce a crosslinked structure by a condensation reaction (silanol condensation) of a silanol group into the photocurable pressure-sensitive adhesive layer (A).

The amount used when using an alkoxysilyl group-containing monomer is not particularly limited. In some embodiments, the amount of the alkoxysilyl group-containing monomer used may be, for example, 0.005% by weight or more, usually 0.01% by weight or more of the total monomer components constituting the adhesive composition (A). It is appropriate, and may be 0.03 weight% or more, and may be 0.05 weight% or more. In addition, from the viewpoint of the level difference absorbability of the pressure-sensitive adhesive composition (A), the usage-amount of the alkoxysilyl group-containing monomer is generally 1.0% by weight or less of the total monomer components. It may be 0.5 weight% or less, and may be 0.1 weight% or less.

A polyfunctional monomer is mentioned as another example of the compound which can be used as an ethylenically unsaturated compound (B). When the adhesive composition (A) containing a polyfunctional monomer is used and the curable adhesive layer (A) is produced by curing the composition, by reacting the above polyfunctional monomer, it is possible to obtain a Curable adhesive layer (A) in which a functional monomer was crosslinked. Examples of polyfunctional monomers include 1,6-hexanediol di(meth)acrylate, 1,12-dodecanediol di(meth)acrylate, ethylene glycol di(meth)acrylate, base) acrylate, propylene glycol di(meth)acrylate, polyethylene glycol di(meth)acrylate, polypropylene glycol di(meth)acrylate, neopentyl glycol di(meth)acrylate, pentaerythritol di Bifunctional monomers such as (meth)acrylate, allyl (meth)acrylate, vinyl (meth)acrylate, divinylbenzene; trimethylolpropane tri(meth)acrylate, Pentaerythritol tri(meth)acrylate, tetramethylolmethane tri(meth)acrylate, dipentaerythritol hexa(meth)acrylate and other polyfunctional monomers with more than three functionalities; other epoxy Acrylate, polyester acrylate, urethane acrylate, etc. Preferred examples of these include 1,6-hexanediol di(meth)acrylate, trimethylolpropane tri(meth)acrylate, and dipentaerythritol hexa(meth)acrylate. A polyfunctional monomer can be used individually by 1 type or in combination of 2 or more types.

The usage-amount when using a polyfunctional monomer is not specifically limited, It can be made into less than 5.0 weight% of all the monomer components which comprise an adhesive composition (A). Thereby, formation of an excessive crosslinked structure can be avoided at the time of formation of the photocurable adhesive layer (A) (that is, the stage before photocuring), and the height difference of the photocurable adhesive layer (A) can be increased. absorbent. The amount of the polyfunctional monomer 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 or less of the total monomer components. It may be 0.3 weight% or less. A polyfunctional monomer may not be used. Also, in some embodiments, from the viewpoint of imparting moderate cohesiveness to the photocurable adhesive layer (A), the usage-amount of the polyfunctional monomer relative to the total monomer components may be, for example, 0.001% by weight. The above may be 0.005% by weight or more, 0.01% by weight or more, or 0.03% by weight or more.

The weight ratio of the BP polymer (A) to the total amount of the BP polymer (A) contained in the adhesive composition (A) and the ethylenically unsaturated compound (B) is not particularly limited, and can be obtained by The level difference absorption property of the photocurable adhesive layer (A) formed from this adhesive composition (A) is set so that the processability of the photocured product may balance suitably. In some embodiments, the weight fraction of the above-mentioned BP polymer (A) may be, for example, 0.5% by weight or more, usually 1% by weight or more, preferably 1.5% by weight or more, more preferably 5% by weight or more. From the viewpoint of enhancing the photocuring 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 above. In addition, from the viewpoint of the ease of preparation and coating of the adhesive composition (A), in some embodiments, the weight ratio of the BP polymer (A) in the above total amount can be lower than 99%, for example. % by weight, may be less than 95% by weight, 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.

The ratio of the weight of the organic solvent to the weight of the entire adhesive composition (A) 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 adhesive composition (A) (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 adhesive composition (A) 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 adhesive composition (A) 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 said adhesive composition (A) contains the compound (namely, monofunctional monomer) (B1) which has at least one ethylenically unsaturated group as said ethylenically unsaturated compound (B). As the monofunctional monomer (B1), an equivalent compound can be selected from the examples of the above-mentioned ethylenically unsaturated compound (B) and used. 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 (B1) to the total amount of the BP polymer (A) and the ethylenically unsaturated compound (B) may be, for example, 1% by weight or more, 5% by weight or more, or 15% by weight. % by weight or more. In some embodiments, the weight ratio of the above-mentioned monofunctional monomer (B1) may be 25% by weight or more, and may be 35% by weight from the viewpoint of easiness of preparation and coatability of the adhesive composition (A). % or more, or 45% by weight or more. In addition, in the above total amount, the weight ratio of the monofunctional monomer (B1) 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, It may be 65 weight% or less, may be 55 weight% or less, and may be 45 weight% or less.

In the aspect where the adhesive composition (A) contains the monofunctional monomer (B1), the glass transition temperature (Tg) obtained by the Fox formula based on the composition of the monofunctional monomer (B1) is not particularly The limit may be, for example, -80°C or more and 250°C or less. From the viewpoint of the compatibility of the polymer derived from the monofunctional monomer (B1) with other components, etc., the Tg based on the composition of the monofunctional monomer (B1) is usually preferably 150° C. or less, and may be 100° C. It may be 70°C or lower, 50°C or lower, or 30°C or lower. In some embodiments, the Tg based on the composition of the monofunctional monomer (B1) is preferably lower than 0° C., more preferably −10° C., from the viewpoint of the height difference absorption of the photocurable adhesive layer (A). °C or lower may be -20°C or lower, -30°C or lower, or -40°C or lower. In addition, from the viewpoint of cohesiveness of the photocurable adhesive layer (A) and workability after photocuring, it is generally advantageous that the Tg based on the composition of the monofunctional monomer (B1) is -60°C or higher. , may be -54°C or higher, may be -50°C or higher, may be -45°C or higher, may be -35°C or higher, or may be -25°C or higher. The above-mentioned Tg can be adjusted by the compounds used as monofunctional monomers and their usage ratio.

In the adhesive composition (A) comprising BP polymer (A) and monofunctional monomer (B1), the photocurable adhesive layer (A) formed by this adhesive composition and its photocuring In the product, Tg (hereinafter referred to as "Tg _A " of BP polymer (A) and Tg (hereinafter referred to as "Tg _B1 " of the monomer composition based on monofunctional monomer (B1).) can be obtained by The Tg difference [°C] (hereinafter also referred to as ΔTg) calculated from Tg _B1 [°C]-Tg _A [°C] 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 between the photocurable pressure-sensitive adhesive layer (A) and its photocured product, it is advantageous that the absolute value of the above-mentioned Tg difference is not too large. In some embodiments, ΔTg may be above -10°C, preferably above 0°C, above 7°C, above 10°C, above 20°C, or above 30°C.

The adhesive composition (A) may contain at least a compound (ie, polyfunctional monomer) (B2) having two or more ethylenically unsaturated groups as the above-mentioned ethylenically unsaturated compound (B). The polyfunctional monomer (B2) 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 (B2) can be set similarly to the ratio which a polyfunctional monomer occupies to the whole monomer component which comprises an adhesive composition (A).

In the form of using a monofunctional monomer (B1) and a polyfunctional monomer (B2) in combination as the ethylenically unsaturated compound (B), the monofunctional monomer (B1) is included in the ethylenically unsaturated compound (B) For example, the weight ratio of 1% by weight can be 1% by weight or more, usually 25% by weight or more is suitable, it can be 50% by weight or more, 75% by weight or more, 95% by weight or more, or 99% by weight. %above. In addition, the weight ratio of the monofunctional monomer (B1) in the ethylenically unsaturated compound (B) may be, for example, 99.9% by weight or less, or may be 99.8% by weight or less.

In the pressure-sensitive adhesive composition (A), the ethylenically unsaturated compound (B) may be contained in the form of a partial polymer, or may be contained in a form in which the entire amount is an unreacted monomer. The adhesive composition (A) of one preferable aspect contains an ethylenic unsaturated compound (B) in the form of a partial polymer. The polymerization method for partially polymerizing the ethylenically unsaturated compound (B) is not particularly limited. For example, photopolymerization by irradiating light such as ultraviolet rays and radiation polymerization by irradiating radiation such as β rays and γ rays can be appropriately selected and used. ; thermal polymerization such as solution polymerization, emulsion polymerization, and bulk polymerization; and other conventionally known various 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 (B) in the said partial polymer is not specifically limited. From the viewpoints of ease of preparation and coating properties of the adhesive composition (A), it is appropriate that the above-mentioned polymerization conversion ratio 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.

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

The above partial polymer can be produced, for example, by irradiating the ethylenically unsaturated compound (B) with ultraviolet rays. When the above-mentioned partial polymer is prepared in the presence of the BP polymer (A), the irradiation conditions of ultraviolet rays are set so that the ethylenically unsaturated groups react and the benzophenone structure is not excited by light. This enables to obtain an adhesive composition (A) comprising a partial polymer of an ethylenically unsaturated compound (B) and a BP polymer (A). 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 ethylenic unsaturated compound (B) previously, you may mix this partial polymer with a BP polymer (A), and you may prepare an adhesive composition (A). When a part of the polymer is prepared by irradiating the ethylenically unsaturated compound (B) with ultraviolet rays in the absence of a component containing a benzophenone structure, as the ultraviolet light source, the light source that does not excite the benzophenone structure and the excitation All light sources can be used.

When preparing the partial polymer of the ethylenically unsaturated compound (B), the reaction of the ethylenically unsaturated group can be promoted 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.

[Photopolymerization Initiator]

In the pressure-sensitive adhesive composition (A), for the purpose of improving or providing photocurability, a photopolymerization initiator may be contained as needed. When the adhesive composition (A) is a solventless type (active energy ray curing type) adhesive composition, it is preferable that the adhesive composition (A) contains a photoinitiator. On the other hand, when the adhesive composition (A) is a solvent type or emulsion type adhesive composition, it does not need to contain a photoinitiator.

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 the benzoin ether-based photopolymerization initiator 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-methylpropan-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 adhesive composition (A), it is preferable to use a photopolymerization initiator (sometimes referred to as 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. "photopolymerization initiator (C)"). When the adhesive composition (A) contains the photopolymerization initiator (C), the adhesive composition (A) is cured to a cured product in which the benzophenone structure of the aforementioned BP polymer (A) remains Starting from the aspect is preferred.

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 adhesive composition (A) may not substantially contain a photopolymerization initiator containing a phosphorus element in a molecule.

Content of the photoinitiator in an adhesive composition (A) is not specifically limited, It can set so that a desired effect can be exhibited suitably. In some embodiments, the content of the photopolymerization initiator can be, for example, about 0.005 parts by weight or more with respect to 100 parts by weight of the monomer components constituting the adhesive composition (A), 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. The photocurability of an adhesive composition (A) improves by increasing content of a photoinitiator. In addition, with respect to 100 parts by weight of the monomer components constituting the adhesive composition (A), the content of the photopolymerization initiator is usually suitably set to 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 adhesive composition (A) or the like, it may be advantageous that the content of the photopolymerization initiator is not too large.

[Crosslinking agent]

In the adhesive composition (A), for example, an isocyanate-based crosslinking agent, an epoxy-based crosslinking agent, an oxazoline-based crosslinking agent, an aziridine-based crosslinking agent, a carbodiimide-based Cross-linking agent, melamine-based cross-linking agent, urea-based cross-linking agent, metal alkoxide-based cross-linking agent, metal chelate-based cross-linking agent, metal salt-based cross-linking agent, hydrazine-based cross-linking agent, amine-based cross-linking agent known cross-linking agents such as As crosslinking agents, peroxides can also be used. When the adhesive composition (A) is a solvent type or emulsion type adhesive composition, it is preferable to contain a crosslinking agent.

The said crosslinking agent can be used individually by 1 type or in combination of 2 or more types. It is preferable that the photocurable adhesive layer (A) formed from the adhesive composition (A) containing a crosslinking agent mainly contains this crosslinking agent in the form after a crosslinking reaction. By using a crosslinking agent, the cohesive force of a photocurable 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 an adhesive composition (A). 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 adhesive composition (A). or more, may be 0.10 parts by weight or more.

[Chain transfer agent]

The adhesive composition (A) 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 an adhesive composition (A). By using a silane coupling agent, the peeling strength with respect to an adherend (for example, a glass plate) can be improved. Moreover, you may contain a silane coupling agent in a photocurable adhesive layer (A). The photocurable adhesive layer (A) containing a silane coupling agent can be formed suitably using the adhesive composition (A) 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 adhesive composition (A) may contain tackifying resins (such as rosin-based, petroleum-based, terpene-based, phenol-based, ketone-based, etc. tackifying resins), viscosity modifiers (such as tackifiers), leveling agents, etc. Various additives conventional in the field of adhesives such as additives, antioxidants, plasticizers, fillers, stabilizers, preservatives, antiaging agents, etc. 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 adhesive composition (A) 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 photocurable adhesive layer (A) or adhesive composition (A) can be set to be lower than 100 parts by weight of the monomer components, for example. 10 parts by weight, and further less than 5 parts by weight. 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 photocurable adhesive layer (A) or the adhesive composition (A) may not contain tackifier resin.

[Photocurable adhesive layer (A)]

The photocurable adhesive layer (A) is formed of a cured product in which the benzophenone structure remains as a cured product of the adhesive composition (A). This benzophenone structure forms a crosslinked structure by ultraviolet irradiation, and can harden a photocurable adhesive layer (A). The photocurable pressure-sensitive adhesive layer (A) before this hardening is a semi-cured state with high fluidity, and shows the excellent level difference absorption property. Therefore, when the photocurable adhesive layer (A) of the above-mentioned photocurable adhesive sheet (A) is bonded to a display panel in which light emitting elements (LED chips) are arranged at high density, it will fully follow the light emitting elements (LED chips). The fine height difference between the LED chips) enables close contact without remaining air bubbles and gaps. On the other hand, the cured photocurable pressure-sensitive adhesive layer (A) exhibits excellent workability. Therefore, it is possible to suppress the occurrence of gaps when cutting the laminate including the cured photocurable adhesive layer (A), and to suppress the occurrence of protruding and sagging of the adhesive layer from the edge during storage. Thus, according to the said photocurable adhesive layer (A) which consists of the said hardened|cured material of the said adhesive composition (A), excellent level difference absorption and processability can be compatible suitably.

Although it does not specifically limit as a preparation method of a photocurable adhesive layer (A), For example, it can manufacture by irradiating an active energy ray to an adhesive composition (A), heat-drying, etc. Specifically, coating (coating) of the pressure-sensitive adhesive composition (A) on a base material or a release liner, followed by drying, curing, or drying and curing as necessary may be exemplified.

In addition, a well-known coating method can be used for coating (coating) of an adhesive composition (A). For example, a coating machine such as a gravure coater, a reverse roll coater, a lip coater, a dip roll coater, a rod coater, a knife coater, a spray coater, a comma coater, or a direct coater can be used. .

When the adhesive composition (A) is cured by irradiation with active energy rays, it is preferable to react the ethylenically unsaturated groups contained in the adhesive composition (A), and the photocurable adhesive It proceeds so that the benzophenone structure contained in layer (A) remains. As an active energy ray for forming a photocurable pressure-sensitive adhesive layer (A), ultraviolet rays are preferable, and it is more preferable that it does not contain the component of a wavelength less than 300 nm, or there is little of this wavelength component.

When the adhesive composition (A) contains a BP polymer (A) and an ethylenically unsaturated compound (B), the photocurable adhesive layer (A) may contain a BP polymer (A) and an ethylenically unsaturated compound derived from A polymer (E) of a saturate compound (B). In this aspect, the adhesive composition (A) may be a composition in which the above-mentioned ethylenically unsaturated compound (B) does not contain ethylenically unsaturated BP. According to the adhesive composition (A) of this composition, the polymer (E) containing BP polymer (A) and the ethylenically unsaturated compound (B) origin can be manufactured, and the said polymer (E) is not Photocurable adhesive layer (A) of a polymer having a benzophenone structure (sometimes referred to as "non-BP polymer").

On the other hand, when the adhesive composition (A) contains a mixture of monomer components constituting the BP polymer (A) or a partial polymer of the mixture of monomer components, the photocurable adhesive layer (A) It may be composed of two or more polymers with different monomer compositions, and at least one of the above two or more polymers is a polymer having a benzophenone structure in a side chain (sometimes referred to as "BP polymer ( A')") photocurable adhesive layer. The said photocurable adhesive layer may contain only 2 or more types of BP polymer (A') as said 2 or more types of polymer, and may contain a non-BP polymer and BP polymer (A') in combination. The non-BP polymer can be formed by using an adhesive composition containing an ethylenically unsaturated compound not having a benzophenone structure and polymerizing the ethylenically unsaturated compound. The BP polymer (A') may be, for example, the BP polymer (A) contained in the above-mentioned adhesive composition (A), or may be a modified product thereof, or may be the above-mentioned adhesive composition (A) The substance formed by copolymerization of ethylenically unsaturated BP contained with other ethylenically unsaturated compounds.

The above-mentioned two or more kinds of polymers may be chemically bonded or may not be bonded. The photocurable adhesive layer (A) of some aspects may contain at least 1 sort(s) of BP polymer so that it may not chemically bond with polymers other than this BP polymer.

Irradiation of an active energy ray for curing the adhesive composition (A) is preferably performed so as to react the ethylenically unsaturated group and leave the benzophenone structure. As the above-mentioned adhesive composition (A), an adhesive composition containing a BP polymer (A) and an ethylenically unsaturated compound (B) can be preferably used. As a light source for curing the adhesive composition (A) to form a photocrosslinkable adhesive, it is preferable to use the above-mentioned black light lamp, UV-LED lamp, etc. that can irradiate components that do not contain wavelengths below 300nm or the wavelength A light source of ultraviolet light with few components.

In a preferred embodiment of the present invention, the maximum value of the transmittance at a wavelength of 200 to 400 nm (preferably at a wavelength of 330 to 400 nm) of the photocurable adhesive layer (A) is greater than that at a wavelength of 400 to 700 nm. rate maximum. The photocurable adhesive layer (A) with excellent light-shielding properties against visible light can achieve a fine height between the metal wiring layer of the self-luminous display device (mini/micro LED display device) and the light emitting element (LED chip) without gaps. Poor sealing, thereby preventing reflection caused by metal wiring, etc., preventing color mixing of light-emitting elements (LED chips), and improving image contrast. On the other hand, the photocurable adhesive layer (A) having a high transmittance in the ultraviolet region (wavelength 200 to 400 nm, preferably 330 to 400 nm) is irradiated with ultraviolet rays so that the benzophenone structure forms a crosslinked structure and When cured, the workability is improved, and it is possible to suppress the lack of glue during cutting and the overflow and sagging of the adhesive layer from the edge during storage.

In addition, in a preferred embodiment of the present invention, the maximum value of the transmittance of the photocurable adhesive layer (A) at a wavelength of 400 to 700 nm (visible light region) is, for example, 80% or less, and may be 70%. Less than, 60% or less, 50% or less, 40% or less, 30% or less, 20% or less, 10% or less, or 5% or less.

In addition, in a preferred embodiment of the present invention, the average transmittance at a wavelength of 200 to 400 nm (preferably at a wavelength of 330 to 400 nm) of the photocurable adhesive layer (A) is greater than the average transmittance at a wavelength of 400 to 700 nm. Overrate. The average transmittance of the photocurable 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, 10% or less, or 5% or less.

The photocurable adhesive layer (A) preferably contains, for example, about 0.1 mg or more of the benzophenone structure per 1 g of the adhesive layer in terms of 4-benzoylphenyl acrylate. Hereinafter, the weight in terms of 4-benzoylphenyl acrylate of the benzophenone structure contained per 1 g of the photocurable adhesive layer (A) may be referred to as the BP equivalent of the adhesive layer (unit: mg/ g). From the viewpoint of obtaining a higher photocuring effect (for example, the effect of improving workability by photocuring), the BP equivalent of the adhesive layer is generally 0.3 mg/g or more. It 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, from the viewpoint of the impact resistance of the joint portion based on the photocured product and the suppression of strain in the photocured product, the BP equivalent of the adhesive layer 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.

(storage modulus)

The storage modulus (G'b85) at 85°C of the photocurable adhesive layer (A) before curing is not particularly limited, for example, it is preferably less than 65 kPa, more preferably 60 kPa or less, further preferably 55 kPa or less, especially It is preferably 50 kPa or less, and may be further 45 kPa or less. Such a configuration is preferable in order to realize the excellent step absorption of the photocurable 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 photocurable adhesive layer (A) before curing at 85° C. can be determined by the composition of the adhesive composition (A) (for example, the Mw of the BP polymer (A), Tg; the weight fraction of BP polymer (A); the composition of the monomer components constituting BP polymer (A) and ethylenically unsaturated compound (B), the type and amount of functional groups; the type and amount of crosslinking agent), etc. Make adjustments.

The storage modulus (G'a10) at 10° C. of the cured photocurable adhesive layer (A) 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, and more preferably 110 kPa or more. It is 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 constitution is preferable in order to realize the excellent processability of the cured photocurable pressure-sensitive adhesive layer (A). 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 cured photocurable adhesive layer (A) at 10°C can be determined by the composition of the adhesive composition (A) (for example, the Mw of the BP polymer (A), Tg, BP equivalent; The weight fraction of BP polymer (A); The composition, the kind and the amount of functional group of the monomer component that constitute BP polymer (A) and ethylenically unsaturated compound (B); The kind and the amount of crosslinking agent amount) etc. to adjust.

The storage modulus (G'a10) of the photocurable adhesive layer (A) after curing at 10°C is compared to the storage modulus at 85°C of the photocurable adhesive layer (A) before curing The ratio (G'a10/G'b85) of the amount (G'b85) is not particularly limited, for example, it is preferably greater than 2.8, more preferably 2.9 or greater, still more preferably 3 or greater, particularly preferably 3.1 or greater, and further may be 3.2 or greater, 3.3 or higher, greater than 3.3, 3.4 or higher, 3.5 or higher, 3.6 or higher, 3.7 or higher, 3.8 or higher, 3.9 or higher, 4 or higher, 5 or higher, 6 or higher, 7 or higher, 8 or higher, 9 or higher, 10 or higher, or 11 or higher. Such a configuration is advantageous in terms of both the excellent level difference absorption of the photocurable adhesive layer (A) before curing and the excellent processability of the photocurable adhesive layer (A) after curing. preferred. 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 storage modulus (G'a10) of the photocurable adhesive layer (A) after curing at 10°C is compared to the storage modulus at 85°C of the photocurable adhesive layer (A) before curing The ratio (G'a10/G'b85) of the amount (G'b85) can be determined by the composition of the adhesive composition (A) (such as Tg, Mw, BP equivalent of BP polymer (A); BP polymer (A) ) weight fraction; constitute BP polymer (A) and ethylenically unsaturated compound (B) monomer component composition, functional group type and amount; crosslinking agent type and amount) etc. to adjust.

The storage modulus (G'b10) at 10°C of the photocurable adhesive layer (A) before curing is not particularly limited, but is preferably 10 kPa or more, more preferably 50 kPa or more, more preferably 70 kPa or more, or 90 kPa or more, 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 photocurable adhesive layer (A) before curing at 10°C can be determined by the composition of the adhesive composition (A) (for example, the Mw of the BP polymer (A), Tg; the weight fraction of BP polymer (A); the composition of the monomer components constituting BP polymer (A) and ethylenically unsaturated compound (B), the type and amount of functional groups; the type and amount of crosslinking agent), etc. Make adjustments.

The storage modulus (G'a85) at 85° C. of the cured photocurable adhesive layer (A) is not particularly limited, but is, for example, preferably 10 kPa or more, preferably 20 kPa, from the viewpoint of handling and handling properties. or more, more preferably 30 kPa or more. 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 cured photocurable adhesive layer (A) at 85°C can be determined by the composition of the adhesive composition (A) (such as the Mw of the BP polymer (A), Tg, BP equivalent; The weight fraction of BP polymer (A); The composition, the kind and the amount of functional group of the monomer component that constitute BP polymer (A) and ethylenically unsaturated compound (B); The kind and the amount of crosslinking agent amount) etc. to adjust.

The storage modulus (G'a25) at 25°C of the cured photocurable adhesive layer (A) 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 It is above 170kPa. Such a constitution is preferable in order to realize the excellent processability of the cured photocurable pressure-sensitive adhesive layer (A). 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 cured photocurable adhesive layer (A) at 25°C can be determined by the composition of the adhesive composition (A) (such as the Mw of the BP polymer (A), Tg, BP equivalent; The weight fraction of BP polymer (A); The composition, the kind and the amount of functional group of the monomer component that constitute BP polymer (A) and ethylenically unsaturated compound (B); The kind and the amount of crosslinking agent amount) etc. to adjust.

The storage modulus (G'b25) at 25° C. of the photocurable adhesive layer (A) before curing is not particularly limited, and is, for example, 300 kPa or less, preferably 250 kPa or less, more preferably 200 kPa or less. Such a configuration is preferable in order to realize the excellent step absorption of the photocurable pressure-sensitive adhesive layer (A) before curing. Moreover, G'b25 is not specifically limited, For example, it is preferable that it is 10 kPa or more, it is more preferable that it is 30 kPa or more, and it is still more preferable that it is 50 kPa or more from a viewpoint of adhesion reliability. The storage modulus (G'b25) of the photocurable adhesive layer (A) before curing at 25° C. can be determined by the composition of the adhesive composition (A) (for example, the Mw of the BP polymer (A), Tg; the weight fraction of BP polymer (A); the composition of the monomer components constituting BP polymer (A) and ethylenically unsaturated compound (B), the type and amount of functional groups; the type and amount of crosslinking agent), etc. Make adjustments.

The storage modulus (G'a25) of the cured adhesive layer A at 25°C is relative to the storage modulus (G'b85) at 85°C of the photocurable adhesive layer (A) before curing. ) ratio (G'a25/G'b85) is not particularly limited, for example, 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 storage modulus (G'a25) of the cured adhesive layer A at 25°C is relative to the storage modulus (G'b85) at 85°C of the photocurable adhesive layer (A) before curing. ) ratio (G'a25/G'b85) can be determined by the composition of the adhesive composition (A) (such as Mw, Tg, BP equivalent of BP polymer (A); weight fraction of BP polymer (A); The composition of the monomer components constituting the BP polymer (A) and the ethylenically unsaturated compound (B), the type and amount of functional groups; the type and amount of the crosslinking agent) and the like are adjusted.

Although the curing conditions in the above-mentioned "photocurable adhesive layer (A) after curing" are not particularly limited, it is preferable that the adhesive layer (A) exhibits ultraviolet rays that are transparent. Ultraviolet rays having a wavelength of 200 to 400 nm are more preferable, and ultraviolet rays having a wavelength of less than 300 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 radiation for curing can be appropriately set as long as the photocurable adhesive layer (A) can be cured without adversely affecting the adherend. 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.

[VOC emissions]

The emission amount of VOC (volatile organic compound) of a photocurable adhesive layer (A) is not specifically limited. The above VOC emission amount may be, for example, 5000 μg/g or less, may be 3000 μg/g or less, or may be 1000 μg/g or less. In some embodiments, the VOC emission of the photocurable adhesive layer (A) is preferably 500 μg/g or less, more preferably 300 μg/g or less, further preferably 100 μg/g or less. The photocurable pressure-sensitive adhesive layer (A) with a small amount of VOC emission has low odor and is preferable from the viewpoint of environmental sanitation. It is also preferable from the viewpoint of suppressing foaming due to volatile organic compounds (VOC) in the photocurable adhesive layer (A) that the VOC emission amount of the photocurable adhesive layer (A) is small and low pollution. of. Regarding the VOC emission amount of the photocurable adhesive layer (A), an appropriate amount (for example, about 1 mg to 2 mg) of the photocurable adhesive layer (A) is used as a measurement sample, and measured by the following method. In addition, it is preferable that the thickness of a measurement sample is 1 mm or less.

[VOC measurement test]

Put the measurement sample into a 20 mL vial and cap it tightly. Next, the vial was heated at 80° C. for 30 minutes, and 1.0 mL of heated gas (sample gas) was injected into a gas chromatography (GC) measurement device using a headspace autosampler (HSS). Based on the obtained gas chromatogram, the amount of gas generated from the above-mentioned measurement sample was determined as an amount converted to n-decane. From the obtained value, the amount of VOC emission (μg/g) per 1 g of the measurement sample was determined. In addition, this n-decane conversion amount was calculated|required by using the calibration curve of n-decane prepared beforehand considering the detection intensity of the generated gas by GCMass as the detection intensity of n-decane. The settings of HSS and GC are as follows.

HSS: Made by Agilent Technologies, model "7694"

Heating time: 30 minutes

Pressurization time: 0.12 minutes

Ring fill time: 0.12 minutes

Ring balance time: 0.05 minutes

Injection time: 3 minutes

Sample loop temperature: 160°C

Transmission line temperature: 200°C

GC device: manufactured by Agilent Technologies, model "6890"

Column: J&W capillary column product name "DB-ffAP" manufactured by GL Science Co., Ltd. (inner diameter 0.533mm x length 30m, film thickness 1.0μm)

Column temperature: 250°C (10°C/min from 40°C to 90°C, then 20°C/min to 250°C, hold for 5 minutes)

Column pressure: 24.3kPa (constant flow mode)

Carrier gas: Helium (5.0mL/min)

Injection port: split (split ratio 12:1)

Injection port temperature: 250°C

Detector: FID

Detector temperature: 250°C

Generally, organic solvents (for example, residues of organic solvents contained in the adhesive composition (A)), the adhesive Unreacted matter of the ethylenically unsaturated compound contained in the agent composition (for example, unpolymerized acrylic monomer. Hereinafter referred to as "residual monomer") and the like. The photocurable pressure-sensitive adhesive layer (A) can suppress the content of such organic solvents and residual monomers to a level satisfying any one of the above-mentioned VOC emissions. The photocurable adhesive layer (A) has a structure in which the amount of residual monomers is limited in this way, and a new crosslink can be formed in the system by utilizing the benzophenone structure possessed by the BP polymer (A), thereby enabling Forms a photocured product with improved processability.

It should be noted that, in principle, the lower the VOC emission amount of the photocurable adhesive layer (A) disclosed here, the better. However, from practical viewpoints such as productivity and cost, in some embodiments, the above-mentioned VOC The amount of emission may be, for example, 10 μg/g or more, 30 μg/g or more, 80 μg/g or more, 150 μg/g or more, or 200 μg/g or more.

The VOC emission amount of the photocurable adhesive layer (A) can be determined by the composition of the adhesive composition (A) (for example, the composition of the monomer components constituting the BP polymer (A) and the ethylenically unsaturated compound (B). , the amount of organic solvent), the curing conditions (heating conditions, ultraviolet irradiation conditions) of the adhesive composition (A) and the like are adjusted.

(Gel rate)

The gel fraction of the photocurable adhesive layer (A) is not particularly limited, but the cohesiveness of the photocurable adhesive layer (A), the adhesion with the photocurable adhesive layer (A) From the viewpoint of sheet handling properties, etc., it is usually appropriate to be 5% or more, preferably 15% or more, may be 25% or more, and may be 35% or more. The gel fraction of the photocurable pressure-sensitive adhesive layer (A) is 100% or less in principle. In addition, from the viewpoint of absorbing the height difference of the surface shape of the adherend, the gel fraction of the photocurable adhesive layer (A) is preferably less than 85%, may be less than 70%, may be less than 55% , It can also be lower than 40%.

The gel fraction was measured by the following method. That is, about 0.5 g of a measurement sample is accurately weighed, and its weight is set to W1. Wrap this measurement sample in a porous PTFE (polytetrafluoroethylene) sheet, immerse it in ethyl acetate at room temperature for 1 week, then dry it, measure the weight W2 of the component insoluble in ethyl acetate, and substitute W1 and W2 into The gel fraction was calculated by the following formula.

Gel rate (%)=W2/W1×100;

As the porous PTFE sheet, Nitto Denko Co., Ltd. product name "NITOFLON NTF1122" or its equivalent can be used.

In some embodiments of the photocurable adhesive layer (A), the photocurable adhesive layer (A) is irradiated with ultraviolet rays using a high-pressure mercury lamp under conditions of an illuminance of 300 mW/cm ² and a cumulative light intensity of 10000 mJ/cm ² . The gel ratio of the obtained photocured product may be, for example, 70% or more, preferably 90% or more, may be 95% or more, and may be 98% or more. The gel ratio of the photocured product is 100% or less in principle. The gel fraction was measured according to the method described above.

The gel ratio of the photocurable adhesive layer (A) can be determined by the composition of the adhesive composition (A) (such as Mw, Tg, BP equivalent of BP polymer (A); the weight of BP polymer (A) Score; Composition of monomer components constituting BP polymer (A) and ethylenically unsaturated compound (B), type and amount of functional groups; type and amount of crosslinking agent), adhesive composition (A), light The curing conditions (heating conditions, ultraviolet irradiation conditions) and the like of the curable adhesive layer (A) are adjusted.

The glass transition temperature (Tg) of a photocurable adhesive layer (A) 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 photocurable adhesive layer (A) is not particularly limited, and may be appropriately set so as to sufficiently seal light-emitting elements arranged on a display panel described later. For example, the thickness of the photocurable adhesive layer (A) is 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. way to adjust. By making the said thickness 1.0 times or more, a photocurable adhesive layer (A) follows a step easily, and a step absorbency improves. Moreover, by making the said thickness into 4.0 or less, deformation|transformation of a photocurable pressure-sensitive adhesive layer (A) is hard to occur, and workability improves.

The thickness of the photocurable 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 photocurable adhesive layer (A) may be 400 μm or less, 300 μm or less, 250 μm or less, or 200 μm or less. By making the said thickness 10 micrometers or more, a photocurable pressure-sensitive adhesive layer (A) follows a step part easily, and a step absorption improves. Moreover, by making the said thickness into 500 micrometers or less, deformation|transformation of a photocurable adhesive layer (A) is hard to occur, and workability improves.

The photocurable adhesive layer (A) exhibits excellent light-shielding properties against visible rays, so even when a metal adherend is laminated on the photocurable adhesive layer (A), reflection on the metal surface, luster. When the metal adherend is laminated on the photocurable 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, It is particularly preferably 10% or less. The glossiness (based on JIS Z 8741-1997) when the metal adherend is laminated on the photocurable adhesive layer (A) is preferably 100% or less, more preferably 80% or less, still more preferably 60% or less, It is particularly preferably 50% or less.

In addition, copper, aluminum, stainless steel, etc. can be used as said metal to-be-adhered body.

[Formation of photocured product]

The photocurable adhesive layer (A) can be photocrosslinked by irradiating ultraviolet rays containing a wavelength component that can excite a benzophenone structure, for example. It is preferable to use a light source capable of irradiating ultraviolet rays containing components having a wavelength of less than 300 nm. Examples of the light source include, but are not limited to, high-pressure mercury lamps, low-pressure mercury lamps, metal halide lamps, and super UV lamps. The light irradiated by the light source may contain a component having a wavelength of 300 nm or more.

It should be noted that as a light source capable of irradiating ultraviolet light that does not contain a wavelength component that can excite a benzophenone structure (for example, a component with a wavelength lower than 300 nm) or has a small amount of such a wavelength component, black light lamps, UV-LED lamps, etc. . These light sources can be preferably employed as light sources for advancing the reaction (polymerization reaction or curing reaction) of the ethylenically unsaturated group by light irradiation in the presence of the benzophenone structure. In the ultraviolet irradiation for reacting an ethylenically unsaturated group, in order to accelerate this reaction, the said photoinitiator (C) can be utilized.

The photocurable adhesive layer (A) may be a composition that does not substantially contain a photopolymerization initiator that absorbs light having a wavelength of 300 nm or more to generate radicals, for example, may substantially not contain a photopolymerization initiator that absorbs light of 380 nm or more (especially 400 nm or more) A photopolymerization initiator that generates free radicals under visible light. This may be advantageous from the viewpoint of the optical properties of the photocurable adhesive layer (A). In addition, the photopolymerization initiator which does not contain the photopolymerization initiator which absorbs the light of wavelength 300nm or more and generates a radical does not contain the said photopolymerization initiator of the form which can generate the said radical (the form which has the part which is cleaved by the said light). agent, may allow the cleavage residue containing the above-mentioned photopolymerization initiator. The photocurable adhesive layer (A) of one preferred embodiment does not substantially contain a photopolymerization initiator containing a phosphorus element in a molecule. The photocurable pressure-sensitive adhesive layer (A) disclosed here may not substantially contain any of a photopolymerization initiator containing a phosphorus element in a molecule and a cleavage residue of the photopolymerization initiator.

[Photocurable Adhesive Sheet (A)]

A photocurable adhesive sheet (A) has a photocurable adhesive layer (A).

The form of a photocurable adhesive sheet (A) will not be specifically limited if it has the adhesive surface formed in the surface of a photocurable 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 both adhesive surfaces are provided by the photocurable adhesive layer (A), or There may be one adhesive surface provided by the photocurable adhesive layer (A), and the other adhesive surface provided by an adhesive layer (other adhesive layer) other than the photocurable adhesive layer (A) Shape. From the viewpoint of bonding adherends together, a double-sided PSA sheet is preferable, and a double-sided PSA sheet in which both surfaces of the sheet are surfaces of the photocurable pressure-sensitive adhesive layer (A) is more preferable.

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

Among the above, from the viewpoint of improving optical properties such as transparency, a substrate-less pressure-sensitive adhesive sheet is preferable, and a double-sided pressure-sensitive adhesive sheet without a substrate consisting only of a photocurable pressure-sensitive adhesive layer (A) is more preferable. Sheet (double-sided adhesive sheet without substrate). In addition, when the photocurable adhesive sheet (A) is an adhesive sheet having a base material, although it is not particularly limited, it is preferable to have a photocurable adhesive sheet on both sides of the base material from the viewpoint of workability. A double-sided PSA sheet (double-sided PSA sheet with substrate) for the agent layer (A).

In addition, the above-mentioned "substrate (substrate layer)" refers to sticking together with the adhesive layer when the photocurable adhesive layer (A) is used (attached) to an adherend (optical member, etc.) The portion of the adherend does not include the release film (release film) that is peeled off when the PSA 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 base material 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 (adhesive layer other than adhesive layer A) as above-mentioned. 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 ( Such as intermediate layer, primer layer, etc.).

The photocurable pressure-sensitive adhesive sheet (A) may be provided with a release film (separator) on the pressure-sensitive 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 to utilize a double A form in which each adhesive surface is protected by one release film whose surface is the release 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 a 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.

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 even more preferably 150 to 350 μm. By making the said thickness 10 micrometers or more, a photocurable adhesive layer (A) follows a step part easily, and can aim at the improvement of a step absorbency. In addition, the thickness of a photocurable adhesive sheet (A) does not include the thickness of a release film.

Since the photocurable pressure-sensitive adhesive sheet (A) contains the said photocurable 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 less than 5%.

Since the photocurable pressure-sensitive adhesive sheet (A) has the photocurable pressure-sensitive adhesive layer (A), it has excellent height difference absorption property before hardening. 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 absorption property also to the high level difference exceeding 80 micrometers.

In addition, since the photocurable adhesive sheet (A) has the photocurable adhesive layer (A), it has excellent workability after curing, and it can suppress the lack of glue during cutting and the adhesive layer from falling during storage. Spill, sag at the end.

Furthermore, since a photocurable adhesive sheet (A) has a photocurable adhesive layer (A), it is also excellent in adhesion reliability.

1 to 3 are diagrams (cross-sectional views) schematically showing one embodiment of the photocurable pressure-sensitive adhesive sheet (A) of the present invention.

One embodiment of the photocurable pressure-sensitive adhesive sheet (A) is shown in FIG. 1 . This photocurable adhesive sheet 1A is constituted in the form of a single-sided adhesive photocurable adhesive sheet including: one surface 10A becomes an adherend The photocurable adhesive layer 10 on the pasting surface (adhesive surface), and the substrate S1 laminated on the other surface 10B of the photocurable adhesive layer 10 . The photocurable adhesive layer 10 is bonded to one surface S1A of the base material S1. As the base material S1, plastic films such as polyester films can be used, for example. The substrate S1 may be, for example, an optical film such as a polarizing plate or a cover member. In the embodiment shown in FIG. 1 , the photocurable adhesive layer 10 has a single-layer structure. PSA sheet 1A before use (before sticking to an adherend), for example, as shown in FIG. . The form of the pressure-sensitive adhesive sheet 50 with a release film. Alternatively, the second surface S1B of the substrate S1 (the surface on the opposite side to the first surface S1A, also referred to as the back surface.) may become a peeling surface, and the adhesive surface 10A may be in contact with the second surface of the substrate S1. The form of the adhesive surface 10A is protected by winding or laminating in the manner of the surface S1B.

The release film is not particularly limited, and for example, a release film made of a resin film, a film substrate such as paper, or a film made of a fluorine-based polymer (polytetrafluoroethylene, etc.), polyolefin-based resin (polyethylene, etc.), can be used. , polypropylene, etc.) low-adhesive materials such as release films formed. For the above-mentioned release treatment, for example, a release treatment agent such as silicone-based or long-chain alkyl-based can be used. In some embodiments, a resin film subjected to release treatment can be preferably used as the release film.

The photocurable pressure-sensitive adhesive sheet (A) may be a substrate-less double-sided pressure-sensitive adhesive sheet composed of a photocurable pressure-sensitive adhesive layer (A). As shown in FIG. 2 , before use, the base-less double-sided adhesive sheet 1B may be a release film in which each side 10A, 10B of the adhesive layer 10 is made into a releasable surface (release surface) at least on the side of the adhesive layer. The form of S3 and S4 protection. Alternatively, the back side of the release film S4 (the surface opposite to the adhesive side) may be a release surface, and the adhesive surface 10B may be wound or laminated so that the adhesive surface 10B abuts against the back side of the release film S4 to protect the adhesive. The shape of the surfaces 10A, 10B. Such a substrate-less double-sided pressure-sensitive adhesive sheet can be used, for example, by bonding a substrate to either surface of the pressure-sensitive adhesive layer.

The photocurable adhesive sheet (A) may be a component of an optical member with an adhesive sheet in which an optical member is bonded to one surface of an adhesive layer. For example, the photocurable adhesive sheet 1A shown in FIG. 1 may be a component of an optical member with an adhesive sheet 100 in which an optical member S5 is bonded to one surface 10A of the adhesive layer 10 as shown in FIG. 3 . . The above-mentioned optical member may be, for example, a glass plate, a resin film, a metal plate, an LED panel described later, or the like.

The photocurable adhesive layer (A) constituting the photocurable adhesive sheet (A) may be a cured layer of the corresponding adhesive composition (A). For example, the photocurable pressure-sensitive adhesive layer (A) may be obtained by providing (for example, applying) the pressure-sensitive adhesive composition (A) to an appropriate surface, and then curing the pressure-sensitive adhesive composition (A). Curing of the adhesive composition (A) can be performed preferably by irradiation of active energy rays. As an active energy ray for forming a photocurable pressure-sensitive adhesive layer (A), ultraviolet rays are preferable, and it is more preferable to use ultraviolet rays that do not contain components having a wavelength of 300 nm or less or have few components of the wavelength.

For the coating of the adhesive composition (A), for example, conventional coating methods such as a gravure roll coater, a reverse roll coater, a lip coater, a dip roll coater, a rod coater, a knife coater, and a spray coater can be used. cloth machine to implement. In the photocurable adhesive sheet (A) having a base material, as a method of providing the photocurable adhesive layer (A) on the base material, a combination of directly applying an adhesive agent on the base material can be used. A direct method of forming the photocurable adhesive layer (A) from the object (A), or a transfer method of transferring the photocurable adhesive layer (A) formed on the peeling surface to the substrate may be used.

<Self-luminous display device>

The self-luminous display device according to the fifth 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, whereby the 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 one embodiment of a self-luminous display device (mini/micro LED display device) according to a fifth aspect of the present invention.

In FIG. 4 , the mini/micro LED display device 200A 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 200A of the present embodiment, the metal wiring layer 22 for transmitting light emission control signals to the LED chips 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 200A 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 photocurable 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 adhesive layer 20 is a cured product of the photocurable 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 200A 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) The photocurable adhesive layer (A) of the photocurable adhesive sheet (A) is laminated on a display panel in which a plurality of light emitting elements are arranged on one side of the substrate, and the photocurable adhesive layer (A) ) A step of sealing the aforementioned light-emitting element.

(2) The process of irradiating ultraviolet-ray to the said photocurable adhesive layer (A) and hardening.

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) according to the fifth aspect of the present invention. In this embodiment, as shown in FIG. 5( a ), a photocurable adhesive sheet 1C of the fourth 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, 1 C of photocurable adhesive sheets are comprised from the photocurable adhesive layer 10 and the covering member 24. In this embodiment, 1 C of photocurable pressure-sensitive adhesive sheets have the covering member 24, but the covering member 24 may not be necessary. 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 FIG. 5( b ), the main part of the photocurable adhesive layer 10 of the photocurable adhesive sheet 1C that is not laminated with the covering member 24 is laminated on the surface of the display panel on which a plurality of LED chips are arranged. On the surface 10A, the LED chip 23 and the metal wiring layer 22 are sealed with the photocurable 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 photocurable pressure-sensitive adhesive layer 10 of the photocurable pressure-sensitive adhesive sheet 1C has high fluidity and exhibits excellent step absorption. Therefore, the photocurable adhesive layer 10 is sealed so that the level difference between the metal wiring layer 22 and the plurality of LED chips 23 is filled without gaps.

Next, as shown in FIG. 5( c ), the photocurable adhesive layer 10 is irradiated with ultraviolet rays to be cured. The benzophenone structure contained in the photocurable adhesive layer 10 is excited by irradiation of ultraviolet rays, and a crosslinked structure is formed by abstraction reaction of hydrogen radicals to start a curing reaction. The ultraviolet rays are not particularly limited as long as they excite the benzophenone structure and cure the photocurable adhesive layer 10 , but are preferably ultraviolet rays through which the photocurable adhesive layer 10 exhibits transparency. That is, the photocurable adhesive layer 10 has high light-shielding properties to visible light and high transmittance to ultraviolet rays, so the photocurable adhesive layer 10 can be cured by ultraviolet rays. (c) of FIG. 5 is an embodiment in which the photocurable adhesive layer 10 is cured by irradiating ultraviolet rays U.

As ultraviolet rays, ultraviolet rays having a wavelength of 200 to 400 nm are preferable, and ultraviolet rays having a wavelength of less than 300 nm are 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, regarding the irradiation time and irradiation method of ultraviolet rays, as long as the photocurable adhesive layer 10 can be cured without adversely affecting the display panel, and the photocurable adhesive layer 10 is cured to show sufficient workability, can be set appropriately. 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 photocurable adhesive layer 10 , as shown in FIG. 5( d ), a self-luminous display device (mini/micro LED display device) 200B can be obtained. In (d) of FIG. 5 , the adhesive layer 20 is an adhesive layer obtained by curing the photocurable adhesive layer 10 . The self-luminous display device (mini/micro LED display device) 200B is an embodiment showing an example of the self-luminous display device (mini/micro LED display device) of the fifth aspect of the present invention.

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.

Example

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

[Example 1]

(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 ( Adhesive composition A was prepared by mixing 16 parts by weight of IBXA) and 0.2 parts by weight of a photopolymerization initiator (manufactured by IGM Regins, trade name "Omnirad 184") having an absorption peak in the wavelength range of 300 nm to 500 nm.

(Preparation of black adhesive composition)

To 100 parts by weight of the above-mentioned adhesive composition A, 0.5 part by weight of a 20% dispersion of a black pigment (manufactured by TOKUSHIKI "9256BLACK") was added to prepare a black adhesive composition B1.

(Production of Photocurable Adhesive Sheet)

The black adhesive composition B1 prepared above was coated on the peeling surface of a 38 μm-thick peeling film R1 (manufactured by Mitsubishi Plastics Co., Ltd., MRF#38) that serves as the peeling surface on one side of the polyester film, and the side of the polyester film was covered. The release film R2 (manufactured by Mitsubishi Plastics Corporation, MRE#38) whose one surface 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 adhesive layer C1 having a thickness of about 100 μm, which is a cured product of the black adhesive composition B1 described above, sandwiched between the release films R1 and R2 was obtained in the form of a substrate-less double-sided adhesive sheet. Photocurable adhesive sheet D1.

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 2]

Black adhesive composition B2 was prepared by adding 1 part by weight of a 20% dispersion of a black pigment (manufactured by TOKUSHIKI "9256BLACK") to 100 parts by weight of adhesive composition A. In the same manner as in Example 1, According to the method, the photocurable adhesive layer C2 having a thickness of about 100 μm as a cured product of the above-mentioned black adhesive composition B2 is obtained in the form of a base-less double-sided adhesive sheet sandwiched by the above-mentioned release films R1 and R2. Photocurable adhesive sheet D2.

[Example 3]

2 parts by weight of a 20% dispersion of a black pigment (manufactured by TOKUSHIKI "9256BLACK") was added to 100 parts by weight of the binder composition A to prepare the black binder composition B3. In the same manner as in Example 1, According to the method, a photocurable adhesive layer C3 having a thickness of about 100 μm as a cured product of the above-mentioned black adhesive composition B3 is obtained in the form of a substrate-free double-sided adhesive sheet sandwiched by the above-mentioned release films R1 and R2. Photocurable adhesive sheet D3.

[Example 4]

Black adhesive composition B4 was prepared by adding 4 parts by weight of a 20% dispersion of a black pigment (manufactured by TOKUSHIKI "9256BLACK") to 100 parts by weight of adhesive composition A. In the same manner as in Example 1, According to the method, the photocurable adhesive layer C4 having a thickness of about 100 μm as a cured product of the above-mentioned black adhesive composition B4 is obtained in the form of a substrate-free double-sided adhesive sheet sandwiched by the above-mentioned release films R1 and R2. Photocurable adhesive sheet D4.

[Comparative example 1]

With respect to 100 parts by weight of the adhesive composition A, except that no black pigment was added, the above-mentioned adhesive composition A was obtained in the form of a double-sided adhesive sheet without a substrate by the same method as in Example 1. Photocurable pressure-sensitive adhesive sheet D5 in which the photocurable pressure-sensitive adhesive layer C5 having a thickness of cured product of about 100 μm is sandwiched between the above-mentioned release films R1 and R2.

[Comparative example 2]

(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.

(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, and 3-glycidoxypropyltrimethoxy as a silane coupling agent An adhesive composition was obtained by using 0.35 parts by weight of oxysilane and 0.45 parts by weight of a polymerization initiator ("Irgacure 651" manufactured by BASF Corporation).

(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 peeling surface of a 38 μm-thick peeling film R1 (manufactured by Mitsubishi Plastics Corporation, MRF#38) that serves as the peeling surface on one side of the polyester film, and the one side of the polyester film was covered. The release film R2 (manufactured by Mitsubishi Plastics Corporation, MRE#38) whose surface 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 50 μm as a cured product of the black PSA composition was sandwiched between the release films R1 and R2 was obtained as a base-less double-sided PSA sheet.

[Example 5]

(Preparation of black adhesive composition)

To 100 parts by weight of the adhesive composition prepared in Comparative Example 2, 4 parts by weight of a 20% dispersion of a black pigment ("9256BLACK" manufactured by TOKUSHIKI) and 0.2 parts by weight of an additional photopolymerization initiator ("Irgacure 651" manufactured by BASF Corporation) were added. 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, MRF#38) that serves as the peeling surface on one side of the polyester film, and the one side of the polyester film was covered. The release film R2 (manufactured by Mitsubishi Plastics Corporation, MRE#38) whose surface 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 6]

Except having made 2 parts of 4-acryloyloxybenzophenone, it carried out similarly to Example 5, and produced the photocurable adhesive sheet.

(evaluate)

The following evaluations were performed using the PSA sheets obtained in the above 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 adhesive sheet of the 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 simulates an LED panel in which a plurality of LED thin films are arranged on a substrate.

(production of adhesive sheet)

Two adhesive sheets produced in Examples 1 to 4 and Comparative Example 1 were laminated to have a thickness of about 200 μm. Five adhesive sheets produced in Comparative Example 2 were laminated 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 1-4 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 release film on one side of the pressure-sensitive adhesive sheet produced in Examples 1 to 4 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 6 belonging to the photocurable adhesive sheet showed excellent height difference followability (level difference absorption) and processability, and the transmittance and reflectance were also suppressed. When used as a sealing material for LED panels , an excellent antireflection effect and an improvement in contrast can be expected. On the other hand, Comparative Example 1, which is a photocurable pressure-sensitive adhesive sheet but does not contain a colorant, exhibits excellent step followability (step absorbability) and processability, but has high transmittance and reflectance, and is used for When used as a sealing material for LED panels, the anti-reflection effect and improvement in contrast cannot be expected. Comparative Example 2, which is a pressure-sensitive adhesive sheet that contains a colorant but does not exhibit photocurability, exhibits excellent step followability (step absorbability), but is poor in workability.

Variations of the present invention are appended below.

[Appendix 1] An adhesive composition comprising a colorant and a polymer (A) having a benzophenone structure in a side chain,

The maximum value of the transmittance at a wavelength of 200-400 nm of the adhesive composition is greater than the maximum value of the transmittance at a wavelength of 400-700 nm.

[Appendix 2] An adhesive composition comprising a colorant and a mixture of monomer components constituting a polymer (A) having a benzophenone structure in its side chain or a polymer having a benzophenone structure in its side chain A partial polymer of a mixture of monomer components of the ketone-structured polymer (A),

The maximum value of the transmittance at a wavelength of 200-400 nm of the adhesive composition is greater than the maximum value of the transmittance at a wavelength of 400-700 nm.

[Additional Note 3] The adhesive composition according to Additional Note 1 or 2, wherein the maximum value of the transmittance of the coloring agent 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 value colorant.

[Appendix 4] The adhesive composition according to any one of Appendices 1 to 3, further comprising an ethylenically unsaturated compound (B).

[Supplementary Note 5] The adhesive composition according to any one of Supplementary Notes 1 to 4, further comprising a photopolymerization initiator (C) that absorbs ultraviolet rays having a wavelength of 300 nm to 500 nm to generate radicals.

[Appendix 6] A photocurable adhesive layer formed of a cured product of the adhesive composition described in any one of Appendices 1 to 5,

The cured product is a cured product in which the benzophenone structure of the polymer (A) having a benzophenone structure in the side chain remains.

[Additional Note 7] The photocurable adhesive layer according to Additional Note 6, wherein 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.

[Additional Note 8] The photocurable adhesive layer according to Additional Note 6 or 7, wherein the photocurable adhesive layer before curing has a low storage modulus (G'b85) at 85°C at 65kPa.

[Supplementary Note 9] The photocurable adhesive layer according to any one of Supplementary Notes 6 to 8, wherein the storage modulus (G 'a10) and the storage elastic modulus (G'b85) at 85 degreeC of the said photocurable adhesive layer before hardening satisfy following relational expression (1).

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

[Supplementary Note 10] The photocurable adhesive layer according to any one of Supplementary Notes 6 to 9, wherein the storage modulus (G 'a10) is 90 kPa or more.

[Supplementary Note 11] The photocurable adhesive layer according to any one of Supplementary Notes 6 to 10, wherein the curing is based on irradiation with ultraviolet light having a wavelength of less than 300 nm and a cumulative light quantity of 3000 mJ/cm ² solidify.

[Supplementary Note 12] A photocurable pressure-sensitive adhesive sheet having the photocurable pressure-sensitive adhesive layer according to any one of Supplementary Notes 6 to 11.

[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 described in appendix 12,

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

The aforementioned photocurable 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:

Laminating the photocurable adhesive layer of the photocurable adhesive sheet described in Supplementary Note 12 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 photocurable adhesive layer process; and

A step of curing the photocurable adhesive layer by irradiating it with ultraviolet rays.

[Supplementary note 16] The production method according to supplementary note 15, wherein the ultraviolet rays are ultraviolet rays having a wavelength of less than 300 nm.

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～1C Photocurable adhesive sheet

10 photocurable adhesive layer

10A One surface (adhesive surface)

10B another surface

S1 Substrate

S1A first side

S1B second side (back)

S2～S4 Peeling film

S5 optical components

50 adhesive sheets with release film

100 components with adhesive sheets

200A, 200B self-luminous display device (mini/micro LED display device)

20 layers of adhesive (after curing)

21 Substrate

22 metal wiring layers

23 Light-emitting components (LED chips)

24 cover components

Claims (16)

1. An adhesive composition comprising a colorant and a polymer (A) having a benzophenone structure in a side chain,

the adhesive composition has 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.

2. An adhesive composition comprising a colorant and a partial polymer which is a mixture of monomer components constituting a polymer (A) having a benzophenone structure in a side chain or a mixture of monomer components constituting a polymer (A) having a benzophenone structure in a side chain,

the adhesive composition has 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 adhesive composition according to claim 1 or 2, wherein the colorant is a colorant in which the maximum value of transmittance at a wavelength of 200 to 400nm is larger than the maximum value of transmittance at a wavelength of 400 to 700 nm.

4. The adhesive composition according to any one of claims 1 to 3, further comprising an ethylenically unsaturated compound (B).

5. The adhesive composition according to any one of claims 1 to 4, further comprising a photopolymerization initiator (C) which absorbs ultraviolet light having a wavelength of 300nm to 500nm to generate radicals.

6. A photocurable adhesive layer formed from a cured product of the adhesive composition according to any one of claims 1 to 5,

the cured product is a cured product in which the benzophenone structure of the polymer (a) having a benzophenone structure in a side chain remains.

7. The photocurable adhesive layer according to claim 6, wherein the maximum value of transmittance at a wavelength of 200 to 400nm is larger than the maximum value of transmittance at a wavelength of 400 to 700 nm.

8. The photocurable adhesive layer according to claim 6 or 7, wherein the storage modulus (G' b 85) at 85 ℃ of the photocurable adhesive layer before curing is lower than 65kPa.

9. The photocurable adhesive layer according to any one of claims 6-8, wherein a storage modulus at 10 ℃ (G 'a 10) of the photocurable adhesive layer after curing and a storage modulus at 85 ℃ (G' b 85) of the photocurable adhesive layer before curing satisfy the following relational expression (1),

2.8<G'a10/G'b85 (1)。

10. the photocurable adhesive layer according to any one of claims 6-9, wherein the storage modulus (G' a 10) at 10 ℃ of the photocurable adhesive layer after curing is 90kPa or more.

11. The photocurable adhesive layer according to any one of claims 6-10, wherein the curing is based on a wavelength of less than 300nm and a cumulative light amount of 3000mJ/cm ² Curing by ultraviolet irradiation.

12. A photocurable adhesive sheet having the photocurable adhesive layer according to any one of claims 6 to 11.

13. A self-luminous display device, comprising:

display panel having a plurality of light-emitting elements arranged on one surface of substrate, and

the photocurable adhesive sheet according to claim 12,

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

the photocurable 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 surface of a substrate.

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

laminating the photocurable adhesive layer of the photocurable adhesive sheet according to claim 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 photocurable adhesive layer; and

and a step of irradiating the photocurable adhesive layer with ultraviolet rays to cure the layer.

16. The manufacturing method according to claim 15, wherein the ultraviolet rays are ultraviolet rays having a wavelength of less than 300 nm.

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