JP7046504B2 - Carrier sheet for flexible devices - Google Patents

Description

The present invention relates to a carrier sheet used for protecting and transporting a flexible device.

In devices such as optical members and electronic members, a carrier sheet composed of a base material and an adhesive layer is provided on the surface of the device in order to transport the device while protecting the surface of the device during processes such as processing, assembly, and inspection. It may be stuck. The carrier sheet is stripped from the device when it no longer needs to be protected and transported.

Conventionally, many devices to be transported are rigid, but in recent years, flexible devices have appeared. For example, in recent years, there has been an active shift from rigid liquid crystal devices to flexible organic light emitting diode (OLED) devices as optical members. Therefore, a carrier sheet compatible with such a flexible device is required.

By the way, in the carrier sheet as described above, the release sheet is peeled off from the adhesive layer at the time of use and is peeled off from the device after use, but at that time, static electricity may be generated due to the peeling charge. Further, the device to which the carrier sheet is attached may be triboelectrically charged during transportation or manufacturing process.

When static electricity is generated, dust and dirt in the air adheres to the device, leading to device malfunction. Therefore, it is required to impart antistatic properties to the carrier sheet so that static electricity is not generated.

Here, Patent Document 1 discloses a silicone pressure-sensitive adhesive composition for transporting a flexible substrate, which contains a silicone pressure-sensitive adhesive and an antistatic agent.

Japanese Patent No. 5406707

Although the invention according to Patent Document 1 considers antistatic properties for flexible devices, it is difficult to obtain sufficient antistatic properties in each step. Further, when the amount of the antistatic agent added is increased in order to obtain sufficient antistatic properties, the adhesive layer becomes cloudy and the haze value increases, so that the adhesive layer cannot be used in the inspection process of the optical system.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a carrier sheet which is excellent in antistatic property in each step and can suppress a haze value low.

In order to achieve the above object, firstly, the present invention is a carrier sheet for a flexible device for protecting and transporting a flexible device, and is an adhesive laminated on one surface side of the base material and the base material. A release sheet laminated on the surface of the pressure-sensitive adhesive layer opposite to the base material is provided, and the base material, the pressure-sensitive adhesive layer, and the release sheet are all antistatic. (Invention 1), the carrier sheet for a flexible device is provided.

The carrier sheet according to the above invention (Invention 1) is excellent in antistatic property in each step because all of the base material, the pressure-sensitive adhesive layer and the release sheet have antistatic property. For example, static electricity is generated when the release sheet is peeled off from the adhesive layer, when the carrier sheet is peeled off from the flexible device, during processes such as processing, laminating, and inspection of the flexible device, or during transportation, or when the carrier sheet is unwound. Is unlikely to occur, and it is possible to prevent dust and dirt in the air from adhering to the flexible device due to static electricity. Further, since each of the base material, the pressure-sensitive adhesive layer and the release sheet has antistatic properties, for example, the amount of the antistatic agent used in the pressure-sensitive adhesive layer is higher than that in the case where a single layer of the pressure-sensitive adhesive layer covers the entire antistatic properties. Can be reduced. As a result, the haze value of the pressure-sensitive adhesive layer and, by extension, the haze value of the carrier sheet as a whole can be suppressed to a low level.

In the above invention (Invention 1), the base material has a base film and an antistatic layer formed on one surface side of the base film, and the pressure-sensitive adhesive layer is the base. It is preferable that the material film is laminated on the base material so as to be located on the other surface side of the material film (Invention 2). It is also preferable that the pressure-sensitive adhesive layer is laminated on the base material so as to be in contact with the other surface of the base film.

In the above inventions (Inventions 1 and 2), it is preferable that the pressure-sensitive adhesive layer contains an antistatic agent (Invention 3).

In the above inventions (Inventions 1 to 3), it is preferable that the release sheet has a support and an antistatic layer formed on at least one surface side of the support (Invention 4).

In the above inventions (Inventions 1 to 4), when a voltage of 100 V is applied for 10 seconds to the carrier sheet for a flexible device obtained by peeling the release sheet in an environment of 23 ° C. and a relative humidity of 50%. The surface resistivity of the exposed surface of the pressure-sensitive adhesive layer is preferably 1 × 10 ⁷ Ω / sq or more and 1 × 10 ¹¹ Ω / sq or less (Invention 5).

In the above inventions (Inventions 1 to 5), what is the pressure-sensitive adhesive layer on the substrate when a voltage of 100 V is applied to the substrate for 10 seconds in an environment of 23 ° C. and a relative humidity of 50%? The surface resistivity of the opposite surface is preferably 1 × 10 ⁷ Ω / sq or more and 1 × 10 ¹¹ Ω / sq or less (Invention 6).

In the above inventions (Inventions 1 to 6), when a voltage of 100 V is applied to the release sheet for 10 seconds in an environment of 23 ° C. and a relative humidity of 50%, the pressure-sensitive adhesive layer side of the release sheet is used. The surface resistivity of the surface is preferably 1 × 10 ⁷ Ω / sq or more and 1 × 10 ¹¹ Ω / sq or less (Invention 7).

In the above inventions (Inventions 1 to 7), what is the pressure-sensitive adhesive layer on the release sheet when a voltage of 100 V is applied to the release sheet for 10 seconds in an environment of 23 ° C. and a relative humidity of 50%? It is preferable that the surface resistivity of the opposite surface is 1 × 10 ⁷ Ω / sq or more and 1 × 10 ¹¹ Ω / sq or less (Invention 8).

In the above inventions (Inventions 1 to 8), the haze value of the carrier sheet for a flexible device excluding the release sheet is preferably 8% or less (Invention 9).

The carrier sheet according to the present invention has excellent antistatic properties in each step and can suppress the haze value to a low level.

It is sectional drawing of the carrier sheet for a flexible device which concerns on one Embodiment of this invention. It is a figure (color) which shows the image and the graph acquired in the dent test.

Hereinafter, embodiments of the present invention will be described.
The carrier sheet for a flexible device according to an embodiment of the present invention (hereinafter, may be simply referred to as a “carrier sheet”) mainly protects the surface of the flexible device during processes such as processing, laminating, and inspection of the flexible device. It is used to transport while carrying.

The flexible device in the present specification refers to a device such as an optical member or an electronic member having flexibility, and examples thereof include a flexible organic light emitting diode (OLED) device, a flexible liquid crystal device, and the like, and a flexible OLED device is particularly preferable.

The carrier sheet according to the present embodiment is a release sheet laminated on a base material, a pressure-sensitive adhesive layer laminated on one surface side of the base material, and a surface of the pressure-sensitive adhesive layer opposite to the base material. The substrate, the pressure-sensitive adhesive layer, and the release sheet all have antistatic properties.

In the carrier sheet according to the present embodiment, as described above, the base material, the pressure-sensitive adhesive layer, and the release sheet all have antistatic properties, so that when the release sheet is peeled off from the pressure-sensitive adhesive layer, or the carrier sheet is used. Static electricity is unlikely to be generated when it is peeled off from a flexible device, during processes such as processing, laminating, and inspection of flexible devices, or when the carrier sheet is unwound, and dust and dirt in the air are flexible due to static electricity. Adhesion to the device can be suppressed. Further, since each of the base material, the pressure-sensitive adhesive layer and the release sheet has antistatic properties, for example, the amount of the antistatic agent used in the pressure-sensitive adhesive layer is higher than that in the case where a single layer of the pressure-sensitive adhesive layer covers the entire antistatic properties. Can be reduced. As a result, the haze value of the pressure-sensitive adhesive layer and, by extension, the haze value of the carrier sheet as a whole can be suppressed to a low level. The carrier sheet having a low haze value as described above has high transparency and is suitable for light emission inspection of flexible OLED devices and the like.

Hereinafter, a carrier sheet, which is an example of the present embodiment, will be described with reference to the drawings.
As shown in FIG. 1, the carrier sheet 1 according to the present embodiment includes a base material 2, an adhesive layer 3, and a release sheet 4. The base material 2 has a base film 21 and a first antistatic layer 22 formed on a surface of the base film 21 opposite to the pressure-sensitive adhesive layer 3 (upper surface in FIG. 1). The release sheet 4 has the support 41, the second antistatic layer 42a formed on the surface of the support 41 on the side of the pressure-sensitive adhesive layer 3 (the upper surface in FIG. 1), and the pressure-sensitive adhesive on the support 41. It has one or both of the third antistatic layers 42b formed on the surface opposite to the layer 3 (lower surface in FIG. 1), preferably the second antistatic layer 42a and the second. It has both of the antistatic layers 42b of 3. Further, the release sheet 4 has the release agent layer 43 at a position closest to the pressure-sensitive adhesive layer 3. When the second antistatic layer 42a is present, the release agent layer 43 is provided on the surface of the second antistatic layer 42a opposite to the support 41, and the second antistatic layer 42a is provided. If it does not exist, it is provided on the surface of the support 41 on the side of the pressure-sensitive adhesive layer 3. The pressure-sensitive adhesive layer 3 is laminated on the base material 2 so as to be in contact with the base film 21. Further, the pressure-sensitive adhesive layer 3 in the present embodiment contains an antistatic agent.

As one of the preferred embodiments of the carrier sheet 1 according to the present embodiment, the carrier sheet 1 is unwound from the winding roll of the carrier sheet 1, the release sheet 4 is peeled off, and the flexible device is placed on the exposed adhesive layer 3. Examples thereof include a mode in which the carrier sheet 1 is peeled off from the flexible device after being processed, laminated, inspected, etc. while being installed and transported. In the above feeding step, in particular, the antistatic property is exhibited by the first antistatic layer 22, and the antistatic property is further improved by providing the third antistatic layer 42b. In particular, during processes such as processing, laminating, and inspection of flexible devices or during transportation, the first antistatic layer 22 can suppress the generation of static electricity due to triboelectric charging. On the other hand, when the release sheet 4 is peeled off from the carrier sheet 1, the antistatic property is exhibited by the pressure-sensitive adhesive layer 3 containing an antistatic agent, and the second antistatic layer 42a is provided to provide the antistatic property. The preventability becomes even better. Further, when the carrier sheet 1 is peeled off from the flexible device, the antistatic property is exhibited particularly by the pressure-sensitive adhesive layer 3 containing the antistatic agent.

One of the second antistatic layer 42a and the third antistatic layer 42b of the release sheet 4 may be omitted. However, since both the second antistatic layer 42a and the third antistatic layer 42b are formed on the release sheet 4, the antistatic property of the carrier sheet 1 becomes more excellent.

Further, in the carrier sheet 1 according to the present embodiment, since the pressure-sensitive adhesive layer 3 has antistatic properties, the anti-static layer is not required on the pressure-sensitive adhesive layer 3 side of the base film 21. However, an antistatic layer may be further formed on the pressure-sensitive adhesive layer 3 side of the base film 21.

1. 1. Each member (1) Base material (1-1) Base material film The base material film 21 is preferably made of a plastic film having physical properties suitable for protection and transportation of flexible devices and each process. As the base film 21, for example, a plastic film made of a resin such as polyethylene terephthalate, polyethylene naphthalate, polybutylene terephthalate, polyimide, polyetherimide, polycarbonate, polymethylpentene, polyphenylene sulfide, and a liquid crystal polymer is preferable, and a single layer is used. It may be a film made of, or it may be a film in which a plurality of layers of the same type or different types are laminated. Among the above, polyethylene terephthalate film is particularly preferable from the viewpoint of handleability, transparency and cost for flexible devices.

Here, when the flexible device to be transported is a flexible OLED device, the light emission inspection of the flexible OLED device is performed at a stricter level than the light emission inspection of the liquid crystal device or the like, so that the carrier sheet 1 has high transparency. Is required. As described above, the carrier sheet 1 according to the present embodiment is suitable for the above-mentioned light emission test because the haze value can be suppressed to a low level. However, in order to further increase the transparency of the carrier sheet 1, the base film 21 is preferably made of a plastic film containing no filler. As a result, the carrier sheet 1 becomes more transparent and more suitable for the light emission inspection of the flexible OLED device.

The plastic film may contain additives such as a filler, a heat resistance improver, an ultraviolet absorber, and a refractive index adjuster as long as the above-mentioned effects of the present embodiment are not impaired.

The base film 21 is subjected to surface treatment by an oxidation method, an unevenness method, or a primer treatment, if desired, for the purpose of improving the adhesion to the first antistatic layer 22 and / or the pressure-sensitive adhesive layer 3. Can be applied. Examples of the oxidation method include corona discharge treatment, plasma discharge treatment, chromium oxidation treatment (wet), flame treatment, hot air treatment, ozone, ultraviolet irradiation treatment and the like, and examples of the unevenness method include sandblasting and sandblasting. Examples include a thermal spraying method. These surface treatment methods are appropriately selected depending on the type of the base film 21.

The thickness of the base film 21 is preferably 25 μm or more in consideration of the handleability when the flexible device is used as an object to be transported, particularly the workability of peeling from the flexible device, and the dent resistance is taken into consideration. , 50 μm or more, more preferably 80 μm or more. Similarly, in consideration of handleability and cost, the thickness is preferably 188 μm or less, particularly preferably 150 μm or less, and further preferably 125 μm or less.

(1-2) Antistatic Layer The first antistatic layer 22 is not particularly limited as long as it can impart desired antistatic properties to the base film 21 and is made of a material having desired transparency. The first antistatic layer 22 is preferably a layer made of, for example, a composition for an antistatic layer containing a conductive polymer and a binder resin.

As the conductive polymer, any conventionally known conductive polymer can be appropriately selected and used, and among them, a polythiophene-based, polyaniline-based or polypyrrole-based conductive polymer is preferable. As the conductive polymer, one type may be used alone, or two or more types may be used in combination.

Examples of the polythiophene-based conductive polymer include polythiophene, poly (3-alkylthiophene), poly (3-thiophene-β-ethanesulfonic acid), and a mixture of polyalkylenedioxythiophene and polystyrene sulfonate (PSS) (PSS). (Including those doped) and the like. Among these, a mixture of polyalkylenedioxythiophene and polystyrene sulfonate is preferable. Examples of the polyalkylene dioxythiophene include poly (3,4-ethylenedioxythiophene) (PEDOT), polypropylene dioxythiophene, poly (ethylene / propylene) dioxythiophene and the like, and among them, poly (3,4-propylene). Ethylene dioxythiophene) is preferred. That is, among the above, a mixture of poly (3,4-ethylenedioxythiophene) and polystyrene sulfonate (PSS-doped PEDOT) is particularly preferable.

Examples of the polyaniline-based conductive polymer include polyaniline, polymethylaniline, and polymethoxyaniline. Examples of the polypyrrole-based conductive polymer include polypyrrole, poly3-methylpyrrole, poly3-octylpyrrole and the like.

The content of the conductive polymer in the composition for the antistatic layer is preferably 0.1 to 30% by mass, particularly preferably 0.2 to 20% by mass, and further preferably 0.3 to 20% by mass. It is preferably 10% by mass. When the content of the conductive polymer is within the above range, good antistatic performance can be obtained, and the strength of the antistatic layer formed from the composition for the antistatic layer is sufficient.

The binder resin used in the antistatic layer composition preferably contains at least one selected from the group consisting of polyester resin, urethane resin and acrylic resin as a main component. These resins may be thermosetting compounds or ultraviolet curable compounds, but since it is necessary to replace the solvent from an aqueous solvent system to an organic solvent system in order to make them ultraviolet curable. From the viewpoint of the number of steps and cost, the thermosetting compound is preferable. Among the above, a thermosetting polyester resin is preferable because of its high adhesion to a plastic film, and a polyester resin having a reactive group that reacts with a cross-linking agent, such as a hydroxyl group, is particularly preferable.

In addition to the above components, the antistatic layer composition may contain a cross-linking agent, a leveling agent, an antifouling agent, and the like.

The cross-linking agent may be any as long as it can cross-link the above resin. For example, if the resin has a hydroxyl group as a reactive group, it is preferable to use an isocyanate-based cross-linking agent, an epoxy-based cross-linking agent, an amine-based cross-linking agent, a melamine-based cross-linking agent, or the like.

The content of the cross-linking agent is preferably 1 to 50 parts by mass, particularly preferably 5 to 40 parts by mass, and further preferably 10 to 30 parts by mass with respect to 100 parts by mass of the binder resin. preferable.

As the leveling agent, for example, a dimethylsiloxane compound, a fluorine compound, a surfactant and the like can be used. In the first antistatic layer 22, it is preferable to use a surfactant from the viewpoint of adhesion to the pressure-sensitive adhesive layer 3. When the antistatic layer composition contains a leveling agent, the smoothness of the antistatic layers 42a and 42b can be improved, and the transparency of the base material 2 becomes higher.

The content of the leveling agent in the composition for the antistatic layer is preferably 0.1 to 10% by mass, particularly preferably 0.2 to 5% by mass, and further preferably 0.5 to 3% by mass. % Is preferable.

Considering the antistatic performance, the thickness of the first antistatic layer 22 is preferably 10 nm or more, more preferably 20 nm or more, and further preferably 30 nm or more. Further, the thickness is preferably 200 nm or less, particularly preferably 150 nm or less, and further preferably 100 nm or less from the viewpoint of strength and cost.

(1-3) Physical properties of the base material (1-3-1) The base material when a voltage of 100 V is applied to the base material 2 for 10 seconds in an environment where the surface resistivity is 23 ° C. and the relative humidity is 50%. The surface resistivity of the surface of the surface opposite to the pressure-sensitive adhesive layer 3 in 2 is preferably 1 × 10 ¹¹ Ω / sq or less, and particularly preferably 5 × 10 ¹⁰ Ω / sq or less, as an upper limit value. Further, it is preferably 1 × 10 ¹⁰ Ω / sq or less. When the upper limit of the surface resistivity is the above, static electricity is generated when the carrier sheet 1 is unwound from the winding roll of the carrier sheet 1 and during processes such as processing, laminating, and inspection of flexible devices or during transportation. It is possible to suppress the occurrence more effectively. The lower limit of the surface resistivity is not particularly limited, but is usually preferably 1 × 10 ⁷ Ω / sq or more, particularly preferably 5 × 10 ⁷ Ω / sq or more, and further 1 It is preferably × 10 ⁸ Ω / sq or more.

The surface resistivity in the present specification is a value measured in accordance with JIS K6911, and the details of the method for measuring the surface resistivity are as shown in a test example described later.

(1-3-2) Haze value The haze value of the base material 2 is preferably 8% or less, particularly preferably 4% or less, and further preferably 1% or less. When the haze value of the base material 2 is as described above, the transparency of the carrier sheet 1 to be attached to the transported object is high, and it is also suitable for the light emission inspection of the flexible OLED device. The lower limit of the haze value is not particularly limited, and is particularly preferably 0%. Here, the haze value in the present specification is a value measured according to JIS K7136: 2000.

(2) Adhesive layer The adhesive layer 3 in the present embodiment contains an antistatic agent. Specifically, the pressure-sensitive adhesive layer 3 is formed of a pressure-sensitive adhesive containing an antistatic agent.

(2-1) Adhesive As the adhesive constituting the adhesive layer 3, it is preferable to select an adhesive suitable for sticking to the transported object (flexible device) and peeling from the transported object. In particular, it is preferable to select an adhesive having excellent removability so that the carrier sheet 1 can be easily peeled off from the flexible device.

Examples of the type of adhesive include acrylic adhesive, silicone adhesive, urethane adhesive, polyester adhesive, and the like, and acrylic adhesive and silicone adhesive are preferable from the viewpoint of removability. .. However, when a general antistatic agent is added to the silicone-based pressure-sensitive adhesive, the transparency of the obtained pressure-sensitive adhesive layer 3 is lowered due to the low compatibility, and the adhesion to the substrate is also lowered. On the other hand, even if a general antistatic agent is added to the acrylic pressure-sensitive adhesive, the influence of compatibility as described above is relatively small. Therefore, acrylic pressure-sensitive adhesives are particularly preferable. Hereinafter, the acrylic pressure-sensitive adhesive containing an antistatic agent will be described.

The acrylic pressure-sensitive adhesive in the present embodiment is obtained by cross-linking (curing) a pressure-sensitive adhesive composition containing one or more (meth) acrylic acid ester copolymers and an antistatic agent, preferably a cross-linking agent. Is preferable. In addition, in this specification, a (meth) acrylic acid ester means both an acrylic acid ester and a methacrylic acid ester. The same applies to other similar terms.

From the viewpoint of removability, the adhesive composition comprises the first (meth) acrylic acid ester copolymer (A) having a relatively large weight average molecular weight as the (meth) acrylic acid ester copolymer. It preferably contains a second (meth) acrylic acid ester copolymer (B) having a relatively small weight average molecular weight. The tacky composition is particularly composed of a first (meth) acrylic acid ester copolymer (A) containing a monomer having a hydroxyl group and a monomer having a carboxyl group as a monomer unit constituting the copolymer, and the first. It has a weight average molecular weight smaller than the weight average molecular weight of the (meth) acrylic acid ester copolymer (A) of No. 1, and contains a monomer having a hydroxyl group and a monomer having a carboxyl group as a monomer unit constituting the copolymer. It is preferable that the adhesive composition contains the second (meth) acrylic acid ester copolymer (B), the isocyanate-based cross-linking agent (C), and the antistatic agent (D). Further, in the adhesive composition, the proportion of the monomer having a hydroxyl group in the monomer constituting the second (meth) acrylic acid ester copolymer (B) is the ratio of the first (meth) acrylic acid ester copolymer ( It is larger than the ratio of the monomer having a hydroxyl group in the monomers constituting A), and constitutes the first (meth) acrylic acid ester copolymer (A) and the second (meth) acrylic acid ester copolymer (B). The carboxyl groups constituting the first (meth) acrylic acid ester copolymer (A) and the second (meth) acrylic acid ester copolymer (B) are added to a total of 100 parts by mass of the monomers. The total number of parts by mass of the monomers contained is 0.1 to 1.0 parts by mass, and the first (meth) acrylic acid ester copolymer (A) and the second (meth) acrylic acid ester copolymer ( It is preferable that the mixing ratio with respect to B) is 90:10 to 10:90 (hereinafter, may be referred to as “tacky composition P”).

The pressure-sensitive adhesive obtained from the pressure-sensitive adhesive composition P contains a relatively small number of the first (meth) acrylic acid ester copolymer (A) having a longer chain length during processing and transportation of the flexible device. It is presumed that it exhibits sufficient adhesion because it has a cross-linking point, has a higher degree of freedom, and is easily deformed. On the other hand, when re-peeling, the movement of the copolymer (A) is constrained by the second (meth) acrylic acid ester copolymer (B) having many cross-linking points, and it is difficult to deform more than a predetermined amount. Therefore, it is presumed that the adhesive strength is relatively small. As a result, the carrier sheet 1 adheres to the flexible device during the process, and the carrier sheet 1 is easily peeled off from the flexible device after the process.

In the adhesive composition P, the first (meth) acrylic acid ester copolymer (A) and the second (meth) acrylic acid ester copolymer (B) are monomer units constituting the copolymer, respectively. As a result, it contains a monomer having a carboxyl group. Monomers having a carboxyl group act as an accelerator for cross-linking. Therefore, in the adhesive composition P, the monomer having a carboxyl group is contained in the copolymer (A) and the copolymer (B) as a monomer constituent unit, so that other cross-linking accelerators such as a tin catalyst can be used. It can be omitted.

In the adhesive composition P, the total number of parts by mass of the monomers constituting the first (meth) acrylic acid ester copolymer (A) and the second (meth) acrylic acid ester copolymer (B) is 100 parts by mass. On the other hand, the total number of parts by mass of the monomers having a carboxyl group constituting the first (meth) acrylic acid ester copolymer (A) and the second (meth) acrylic acid ester copolymer (B) is 0. It is preferably 1 to 1.0 part by mass, particularly preferably 0.15 to 0.8 part by mass, and further preferably 0.3 to 0.6 part by mass. When the total number of parts by mass of the monomers having a carboxyl group is 1.0 part by mass or less, the crosslinking reaction is excessively promoted, and the adhesive composition P is prevented from gelling before the formation of the adhesive. , Sufficient pot life can be secured. On the other hand, when the total number of parts by mass of the monomers having a carboxyl group is 0.1 parts by mass or more, the effect of promoting cross-linking can be obtained.

The first (meth) acrylic acid ester copolymer (A) preferably contains 0.01 to 2.0% by mass of a monomer having a carboxyl group as a monomer unit constituting the copolymer. It is preferably contained in an amount of 0.05 to 1.5% by mass, more preferably 0.3 to 1.0% by mass. When the content of the monomer is 2.0% by mass or less, the pot life of the adhesive composition becomes more excellent. Further, when the content of the monomer is 0.01% by mass or more, the effect of promoting cross-linking by the carboxyl group is sufficiently obtained, and as a result, the cross-linking structure formed mainly of the copolymer (B) is formed. A structure in which the copolymer (A) is bonded via a hydroxyl group is satisfactorily formed in a part thereof, and the high-speed adhesive force of the obtained pressure-sensitive adhesive sheet can be suppressed to a low level.

The second (meth) acrylic acid ester copolymer (B) preferably contains 0.01 to 0.99% by mass of a monomer having a carboxyl group as a monomer unit constituting the copolymer. It is preferably contained in an amount of 0.05 to 0.8% by mass, more preferably 0.2 to 0.6% by mass. When the content of the monomer is 0.99% by mass or less, the pot life of the adhesive composition becomes more excellent. Further, when the content of the monomer is 0.01% by mass or more, the effect of promoting cross-linking by the carboxyl group is obtained, whereby a good cross-linking structure is formed, and the obtained pressure-sensitive adhesive sheet is removable. It will be excellent.

Examples of the monomer having a carboxyl group include ethylenically unsaturated carboxylic acids such as acrylic acid, methacrylic acid, crotonic acid, maleic acid, itaconic acid, citraconic acid and vinyl acetate. These may be used alone or in combination of two or more. From the viewpoint of promoting cross-linking, it is particularly preferable to use acrylic acid as the monomer having a carboxyl group.

In the adhesive composition P, the first (meth) acrylic acid ester copolymer (A) and the second (meth) acrylic acid ester copolymer (B) are monomer units constituting the copolymer, respectively. As a result, it contains a monomer having a hydroxyl group. Since the adhesive composition according to the present embodiment contains an isocyanate-based cross-linking agent (C) as a cross-linking agent, a hydroxyl group having excellent reactivity with an isocyanate group serves as a cross-linking point in the copolymers (A) and (B). It works.

In the adhesive composition P, the ratio of the monomer having a hydroxyl group in the monomer constituting the second (meth) acrylic acid ester copolymer (B) is the ratio of the monomer having a hydroxyl group to the first (meth) acrylic acid ester copolymer (A). It is preferable that it is larger than the ratio of the monomer having a hydroxyl group in the monomers constituting the above. As described above, since the lower molecular weight copolymer (B) has more hydroxyl groups, the copolymer (B) tends to restrain the copolymer (A) at the time of re-peeling, and the copolymer (A) adheres. The force is sufficiently reduced.

The first (meth) acrylic acid ester copolymer (A) preferably contains 0.01 to 5% by mass of a monomer having a hydroxyl group as a monomer unit constituting the copolymer, particularly 0.05. It is preferably contained in an amount of about 1% by mass, more preferably 0.1 to 0.5% by mass.

The second (meth) acrylic acid ester copolymer (B) preferably contains 0.1 to 10% by mass of a monomer having a hydroxyl group as a monomer unit constituting the copolymer, particularly 0.6. It is preferably contained in an amount of about 8% by mass, more preferably 1.1 to 5% by mass.

Examples of the monomer having a hydroxyl group include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, and (. Examples thereof include (meth) acrylic acid hydroxyalkyl esters such as 3-hydroxybutyl (meth) acrylic acid and 4-hydroxybutyl (meth) acrylic acid. These may be used alone or in combination of two or more. In particular, 4-hydroxybutyl acrylate shows high reactivity in the cross-linking reaction, and therefore, from the viewpoint of removability, it is preferable to use 4-hydroxybutyl acrylate as the monomer having a hydroxyl group.

In the adhesive composition P, the second (meth) acrylic acid ester copolymer (B) is a (meth) acrylic acid ester having an alkylene oxide chain as a monomer unit constituting the copolymer (hereinafter, “alkylene”). It may also be referred to as "oxide chain-containing acrylic acid ester"). The alkylene of the alkylene oxide chain is preferably an alkylene having 2 to 4 carbon atoms, and more preferably an ethylene oxide having 2 carbon atoms. In this case, the average number of moles of the alkylene oxide chain added in one molecule of the alkylene oxide chain-containing acrylic acid ester is preferably 1 to 20 mol, particularly preferably 3 to 15 mol, and further preferably 6 to 10. It is preferably mol. Since the second (meth) acrylic acid ester copolymer (B) contains an alkylene oxide chain-containing (meth) acrylic acid ester as a monomer unit, an ionic conductive antistatic agent (D) is added to this pressure-sensitive adhesive. In this case, the mobility of the antistatic agent (D) in the pressure-sensitive adhesive is increased, so that the effect of the antistatic agent (D) can be further obtained. Although the first (meth) acrylic acid ester copolymer (A) may contain an alkylene oxide chain-containing (meth) acrylic acid ester as a monomer unit constituting the copolymer, it is a copolymer. Due to the high molecular weight of (A), the viscosity of the adhesive composition may increase too much and the processability may deteriorate. Therefore, it is preferable that the alkylene oxide chain-containing (meth) acrylic acid ester is contained only in the second (meth) acrylic acid ester copolymer (B). Further, it is preferable that the terminal of the alkylene oxide chain is protected with an alkyl group having 1 to 4 carbon atoms so as not to react with the cross-linking agent (C). Further, from the viewpoint of further exerting the effect of adding the antistatic agent (D) and achieving compatibility with the copolymer (A), the alkylene oxide chain is used as a monomer unit in the copolymer (B). The content (meth) acrylic acid ester is preferably contained in an amount of 1 to 30% by mass, more preferably 5 to 20% by mass, and particularly preferably 10 to 17% by mass.

In the adhesive composition P, the first (meth) acrylic acid ester copolymer (A) and the second (meth) acrylic acid ester copolymer (B) are monomer units constituting the copolymer, respectively. It is preferable to contain a (meth) acrylic acid alkyl ester having 1 to 20 carbon atoms in the alkyl group. This makes it possible to obtain a pressure-sensitive adhesive that exhibits the desired stickiness.

Examples of the (meth) acrylic acid alkyl ester having an alkyl group having 1 to 20 carbon atoms (hereinafter, may be referred to as “(meth) acrylic acid alkyl ester”) include methyl acrylate and ethyl (meth) acrylic acid. , (Meta) propyl acrylate, (meth) n-butyl acrylate, (meth) n-pentyl acrylate, (meth) n-hexyl acrylate, (meth) 2-ethyl hexyl acrylate, (meth) isooctyl acrylate , (Meta) n-decyl acrylate, (meth) n-dodecyl acrylate, myristyl (meth) acrylate, palmityl (meth) acrylate, stearyl (meth) acrylate and the like. Above all, from the viewpoint of obtaining more preferable adhesiveness, it is preferable to use a (meth) acrylic acid alkyl ester having an alkyl group having 4 to 8 carbon atoms, and examples thereof include butyl acrylate and 2-acrylic acid. Ethylhexyl can be mentioned. In particular, it is preferable to use both butyl acrylate and 2-ethylhexyl acrylate.

From the viewpoint of imparting tackiness to the obtained pressure-sensitive adhesive and ensuring the blending ratio of the above-mentioned monomer having a hydroxyl group and the monomer having a carboxyl group, the first (meth) acrylic acid ester copolymer (A) and the first It is preferable that each of the (meth) acrylic acid ester copolymers (B) of 2 contains 60 to 99.8% by mass of the (meth) acrylic acid alkyl ester as a monomer constituent unit. Further, it is more preferable that the copolymer (A) contains 85 to 99.6% by mass of the (meth) acrylic acid alkyl ester as a monomer constituent unit. Further, it is more preferable that the copolymer (B) contains 65 to 85% by mass of the (meth) acrylic acid alkyl ester as a monomer constituent unit.

When both 2-ethylhexyl acrylate and butyl acrylate are used as the (meth) acrylic acid alkyl ester, the first is from the viewpoint of obtaining both adhesion and removability at a high level during transportation and the like. The ratio of 2-ethylhexyl acrylate to butyl acrylate in each of the (meth) acrylic acid ester copolymer (A) and the second (meth) acrylic acid ester copolymer (B) is 95 in terms of mass. : 5 to 50:50 is preferable, and 90:10 to 60:40 is particularly preferable. In the copolymer (A), the ratio is more preferably 74:26 to 65:35 in terms of mass. Further, in the copolymer (B), the ratio is more preferably 85:15 to 76:24 in terms of mass.

In the adhesive composition P, the first (meth) acrylic acid ester copolymer (A) and the second (meth) acrylic acid ester copolymer (B) are, if desired, monomers constituting the polymer. As a unit, other monomers may be contained. As the other monomer, a monomer having no reactive functional group is preferable so as not to interfere with the action of the monomer having a carboxyl group and the monomer having a hydroxyl group. Examples of such other monomers include alkoxyalkyl group-containing (meth) acrylics such as methoxymethyl (meth) acrylate, methoxyethyl (meth) acrylate, ethoxymethyl (meth) acrylate, and ethoxyethyl (meth) acrylate. (Meta) acrylic acid ester having an aromatic ring such as acid ester, (meth) acrylic acid phenyl, (meth) acrylic acid benzyl, acrylic acid ester such as silicone (meth) acrylate, fluorine (meth) acrylate, acrylamide, methacryl It has a non-crosslinkable acrylamide such as amide and acryloylmorpholine, and a non-bridgeable tertiary amino group such as (meth) acrylate N, N-dimethylaminoethyl and (meth) acrylate N, N-dimethylaminopropyl. Examples thereof include vinyl monomers such as (meth) acrylic acid ester, vinyl acetate, N-vinylpyrrolidone, and styrene. These may be used alone or in combination of two or more.

In the adhesive composition P, the above-mentioned first (meth) acrylic acid ester copolymer (A) may be used alone or in combination of two or more. In addition, the above-mentioned second (meth) acrylic acid ester-based copolymer (B) may be used alone or in combination of two or more.

In the adhesive composition P, as described above, the second (meth) acrylic acid ester copolymer (B) has more cross-linking points than the first (meth) acrylic acid ester copolymer (A). In addition, the weight average molecular weight of the second (meth) acrylic acid ester copolymer (B) is smaller than the weight average molecular weight of the first (meth) acrylic acid ester copolymer (A). This makes it possible to effectively achieve both removability and adhesion during transportation of the flexible device.

The weight average molecular weight of the first (meth) acrylic acid ester copolymer (A) is preferably 50,000 to 500,000, particularly preferably 100,000 to 400,000, and further preferably 150,000 to 30. It is preferably 10,000. The weight average molecular weight in the present specification is a value in terms of standard polystyrene measured by a gel permeation chromatography (GPC) method.

The weight average molecular weight of the second (meth) acrylic acid ester copolymer (B) is preferably 2,000 to 100,000, particularly preferably 5,000 to 50,000, and further. It is preferably 10,000 to 20,000.

In the adhesive composition P, the blending ratio of the first (meth) acrylic acid ester copolymer (A) and the second (meth) acrylic acid ester copolymer (B) based on the mass is 90. : 10 to 10:90 is preferable. In particular, it is preferable that the blending amount of the second (meth) acrylic acid ester copolymer (B) is larger than the blending amount of the first (meth) acrylic acid ester copolymer (A). Specifically, the compounding ratio is preferably 45:55 to 10:90, particularly preferably 42:58 to 20:80, and further preferably 40:60 to 30:70. preferable. Since the amount of the second (meth) acrylic acid ester copolymer (B) is larger, a series of processes is completed while exhibiting sufficient adhesion during transportation and processing of the flexible device to prevent peeling. After that, the effect that the flexible device can be peeled off without adhesive residue can be obtained at a high level.

The isocyanate-based cross-linking agent (C) contains at least a polyisocyanate compound. Examples of the polyisocyanate compound include aromatic polyisocyanates such as tolylene diisocyanate, diphenylmethane diisocyanate, and xylylene diisocyanate, aliphatic polyisocyanates such as hexamethylene diisocyanate, isophorone diisocyanates, and alicyclic polyisocyanates such as hydrogenated diphenylmethane diisocyanates. , And their biurets, isocyanates, and adducts, which are reactants with low molecular weight active hydrogen-containing compounds such as ethylene glycol, propylene glycol, neopentyl glycol, trimethylolpropane, and castor oil. Of these, it is preferable to use an isocyanurate-type trimer of 1,6-hexamethylene diisocyanate. These may be used individually by 1 type, or may be used in combination of 2 or more type.

The content of the isocyanate-based cross-linking agent (C) is 100 parts by mass in total of the first (meth) acrylic acid ester copolymer (A) and the second (meth) acrylic acid ester copolymer (B). The amount is preferably 0.1 to 10 parts by mass, particularly preferably 1 to 8 parts by mass, and further preferably 2 to 6 parts by mass.

The antistatic agent (D) may be any as long as it can impart antistatic properties to the obtained pressure-sensitive adhesive, and examples thereof include ionic compounds and nonionic compounds. Among them, the antistatic agent (D) has ionic conductivity. Ionic compounds are preferred. The ionic compound may be liquid or solid at room temperature, but is preferably solid at room temperature from the viewpoint of easily exhibiting stable antistatic properties even when exposed to durable conditions. .. Here, the ionic compound in the present specification means a compound in which cations and anions are mainly bound by electrostatic attraction.

As the ionic compound, a nitrogen-containing onium salt, a sulfur-containing onium salt, a phosphorus-containing onium salt, an alkali metal salt or an alkaline earth metal salt is preferable, and the obtained pressure-sensitive adhesive is particularly a nitrogen-containing onium salt or a nitrogen-containing onium salt from the viewpoint of excellent durability. Alkali metal salts are preferable, and nitrogen-containing onium salts are more preferable. The nitrogen-containing onium salt is preferably an ionic compound composed of a nitrogen-containing heterocyclic cation and its counter anion.

As the nitrogen-containing heterocyclic skeleton of the nitrogen-containing heterocyclic cation, a pyridine ring, a pyrimidine ring, an imidazole ring, a triazole ring, an indole ring and the like are preferable, and a pyridine ring is particularly preferable. Further, as the cation of the alkali metal salt, lithium ion, potassium ion or sodium ion is preferable, and lithium ion or potassium ion is particularly preferable.

On the other hand, as the anion constituting the ionic compound, a halide phosphate anion or a sulfonylimide-based anion is preferably mentioned. As the halide anion, hexafluorophosphate and the like are preferably mentioned. Moreover, as a sulfonylimide-based anion, bis (fluoroalkylsulfonyl) imide, bis (fluorosulfonyl) imide and the like are preferably mentioned.

Specific examples of the antistatic agent (D) include N-butyl-4-methylpyridinium hexafluorophosphate, N-hexyl-4-methylpyridinium hexafluorophosphate, N-octylpyridinium hexafluorophosphate, and N-octyl-4. -Methylpyridinium hexafluorophosphate, N-dodecylpyridinium hexafluorophosphate, N-tetradecylpyridinium hexafluorophosphate, N-hexadecylpyridinium hexafluorophosphate, N-dodecyl-4-methylpyridinium hexafluorophosphate, N-tetradecyl-4 -Pyridinium hexafluorophosphate-based compounds such as methylpyridinium hexafluorophosphate and N-hexadecyl-4-methylpyridinium hexafluorophosphate; N-decylpyridinium bis (fluorosulfonyl) imide, 1-ethylpyridinium bis (fluorosulfonyl) imide, 1 -Butylpyridinium bis (fluorosulfonyl) imide, 1-hexylpyridinium bis (fluorosulfonyl) imide, 1-butyl-3-methylpyridinium bis (fluorosulfonyl) imide, 1-butyl-4-methylpyridinium bis (fluorosulfonyl) Imide, 1-hexyl-3-methylpyridinium bis (fluorosulfonyl) imide, 1-butyl-3,4-dimethylpyridinium bis (fluorosulfonyl) imide, potassium bis (fluorosulfonyl) imide, lithium bis (fluorosulfonyl) imide , Fluorosulfonylimide-based compounds such as potassium bis (fluoromethanesulfonyl) imide and lithium bis (fluoromethanesulfonyl) imide. Among these, from the viewpoint of compatibility with the (meth) acrylic acid ester copolymer (A), N-butyl-4-methylpyridinium hexafluorophosphate, N-hexyl-4-methylpyridinium hexafluorophosphate, N- Octyl-4-methylpyridinium hexafluorophosphate, N-decylpyridinium bis (fluorosulfonyl) imide, and potassium bis (fluorosulfonyl) imide are preferred, especially N-octyl-4-methylpyridinium hexafluorophosphate, and potassium bis (. Fluorosulfonyl) imide is preferred. The above antistatic agent (D) may be used alone or in combination of two or more.

When two or more kinds are combined, it is preferable to use a pyridinium hexafluorophosphate compound and a fluorosulfonylimide compound in combination, particularly N-octyl-4-methylpyridinium hexafluorophosphate and potassium bis (fluorosulfonyl) imide. It is preferable to use. As a result, the antistatic property of the obtained adhesive becomes more excellent. The compounding ratio (mass basis) of the pyridinium hexafluorophosphate compound and the fluorosulfonylimide compound is preferably 90:10 to 10:90, and particularly preferably 80:20 to 20:80. Further, it is preferably 75:25 to 55:45.

The content of the antistatic agent (D) in the adhesive composition P is preferably 0.1 part by mass or more with respect to 100 parts by mass of the (meth) acrylic acid ester copolymer (A). It is preferably 0.5 parts by mass or more, more preferably 1.0 part by mass or more, and most preferably 1.5 parts by mass or more. The content is preferably 10 parts by mass or less, particularly preferably 8 parts by mass or less, and further preferably 5 parts by mass or less. In the carrier sheet 1 according to the present embodiment, the base material 2, the pressure-sensitive adhesive layer 3, and the release sheet 4 each have antistatic properties, so that the antistatic agent (D) in the pressure-sensitive adhesive composition P is described above. The content of can be relatively low. Therefore, the haze value of the obtained pressure-sensitive adhesive layer 3 and, by extension, the haze value of the carrier sheet 1 as a whole can be suppressed to a low level. Further, when the content of the antistatic agent (D) is within the above range, the antistatic property can be effectively exhibited and the deterioration of physical properties such as durability and warpage suppression can be prevented. can.

The adhesive composition P may contain a plasticizer. By containing the plasticizer, the adhesive strength of the obtained adhesive can be easily controlled, and the removability can be made excellent.

Specific examples of the plasticizer include tributyl acetylcitrate, tetraethylene glycol dimethyl ether and the like.

The content of the plasticizer is 1 to 20 with respect to a total of 100 parts by mass of the first (meth) acrylic acid ester copolymer (A) and the second (meth) acrylic acid ester copolymer (B). It is preferably parts by mass, particularly preferably 3 to 15 parts by mass, and more preferably 6 to 12 parts by mass.

If desired, the tacky composition P contains various additives usually used for acrylic pressure-sensitive adhesives, such as tackifiers, antioxidants, UV absorbers, light stabilizers, softeners, fillers, and refractive indexes. Adjusters and the like can be added.

The adhesive composition P preferably does not contain a tin compound, and particularly preferably does not contain an organic tin compound. In the adhesive composition P, since cross-linking is promoted by the monomer having a carboxyl group, it is not necessary to contain a tin compound such as a tin catalyst as a cross-linking accelerator. Since the adhesive composition P does not contain a tin compound, it is possible to obtain a pressure-sensitive adhesive having a reduced burden on the environment.

The adhesive composition P can be produced, for example, as follows.
That is, first, the (meth) acrylic acid ester copolymers (A) and (B) are separately prepared separately in a polymerization solvent described later by a usual radical polymerization method. Next, the obtained solutions of both copolymers are mixed, and a diluting solvent is added so that the solid content concentration becomes 10 to 40% by mass. Then, an isocyanate-based cross-linking agent (C), an antistatic agent (D), and if desired, a plasticizer or an additive are added, and the mixture is sufficiently mixed to obtain a tacky composition (coating solution) diluted with a solvent. obtain.

Examples of the diluting solvent include aliphatic hydrocarbons such as hexane, heptane and cyclohexane, aromatic hydrocarbons such as toluene and xylene, halogenated hydrocarbons such as methylene chloride and ethylene chloride, methanol, ethanol, propanol and butanol. Alcohols such as 1-methoxy-2-propanol, ketones such as acetone, methyl ethyl ketone, 2-pentanone, isophorone, cyclohexanone, esters such as ethyl acetate and butyl acetate, and cellosolve solvents such as ethyl cellosolve are used.

Further, the adhesive composition P is preferably produced by the serial polymerization shown below.

In particular,
(1) In a mixed solution (a) containing a monomer constituting the first (meth) acrylic acid ester copolymer (A), radical polymerization is carried out at a conversion rate of 50 to 90% to obtain the first (meth). After producing the acrylic acid ester copolymer (A),
(2) A mixed solution (b) containing a monomer constituting the second (meth) acrylic acid ester copolymer (B) is added, and the monomer and the first (meth) acrylic acid ester copolymer ( The monomer remaining during the polymerization of A) is radically copolymerized in the presence of the first (meth) acrylic acid ester copolymer (A), preferably at a conversion rate of 70 to 100%, to obtain a second. The (meth) acrylic acid ester copolymer (B) is produced, and then the (meth) acrylic acid ester copolymer (B) is produced.
(3) An isocyanate-based cross-linking agent (C), an antistatic agent (D), and if desired, a plasticizer and various additives are added.

The monomer constituting the first (meth) acrylic acid ester copolymer (A) contained in the mixed liquid (a) is as described above. Further, the content of the monomer having a carboxyl group, the monomer having a hydroxyl group and the (meth) acrylic acid alkyl ester in the mixed solution (a) is the same as that of the first (meth) acrylic acid ester copolymer (A). The constituent monomer unit can be the same as the above-mentioned content.

The monomer constituting the second (meth) acrylic acid ester copolymer (B) contained in the mixed liquid (b) is as described above. Further, the contents of the monomer having a carboxyl group, the monomer having a hydroxyl group, the alkylene oxide chain-containing (meth) acrylic acid ester and the (meth) acrylic acid alkyl ester in the mixed solution (b) are the second (meth), respectively. ) The content of the monomer unit constituting the acrylic acid ester copolymer (B) can be the same as described above.

The mixing ratio of the mixed liquid (a) and the mixed liquid (b) is preferably 90:10 to 10:90 in terms of mass. In particular, the blending amount of the mixed liquid (b) is preferably larger than the blending amount of the mixed liquid (a), and for example, the blending ratio is preferably 45:55 to 10:90, and in particular. It is preferably 42:58 to 20:80, and more preferably 40:60 to 30:70.

The blending amounts of the isocyanate-based cross-linking agent (C) and the plasticizer may be the same as the above-mentioned amounts as the contents in the adhesive composition P, respectively. In this case, with respect to a total of 100 parts by mass of the first (meth) acrylic acid ester copolymer (A) and the second (meth) acrylic acid ester copolymer (B) produced in the above step (2). Therefore, the above-mentioned amount of the isocyanate-based cross-linking agent (C) or the plasticizer can be used.

The above-mentioned serial polymerization can be carried out by a solution polymerization method or the like using a polymerization initiator, if desired. Examples of the polymerization solvent include ethyl acetate, n-butyl acetate, isobutyl acetate, toluene, acetone, hexane, methyl ethyl ketone and the like, and two or more of them may be used in combination.

Examples of the polymerization initiator include azo compounds and organic peroxides, and two or more of them may be used in combination. Examples of the azo compound include 2,2'-azobisisobutyronitrile, 2,2'-azobis (2-methylbutyronitrile), 1,1'-azobis (cyclohexane1-carbonitrile), and 2, , 2'-azobis (2,4-dimethylvaleronitrile), 2,2'-azobis (2,4-dimethyl-4-methoxyvaleronitrile), dimethyl 2,2'-azobis (2-methylpropionate) 4,4'-azobis (4-cyanovaleric acid), 2,2'-azobis (2-hydroxymethylpropionitrile), 2,2'-azobis [2- (2-imidazolin-2-yl) Propane] and the like.

Examples of the organic peroxide include benzoyl peroxide, t-butyl perbenzoate, cumene hydroperoxide, diisopropyl peroxydicarbonate, di-n-propyl peroxydicarbonate, and di (2-ethoxyethyl) peroxy. Examples thereof include dicarbonate, t-butylperoxyneodecanoate, t-butylperoxyvivarate, (3,5,5-trimethylhexanoyl) peroxide, dipropionyl peroxide, diacetyl peroxide and the like.

The concentration and viscosity of the coating solution of the adhesive composition prepared as described above may be any range as long as it can be coated, and is not particularly limited and can be appropriately selected depending on the situation. For example, the adhesive composition P is diluted to a concentration of 10 to 40% by mass. It should be noted that the addition of a diluting solvent or the like is not a necessary condition when obtaining the coating solution, and the diluting solvent may not be added as long as the adhesive composition P has a viscosity that allows coating.

A preferable pressure-sensitive adhesive constituting the pressure-sensitive adhesive layer 3 is obtained by cross-linking the pressure-sensitive adhesive composition P. Crosslinking of the adhesive composition P can be performed by heat treatment. In addition, this heat treatment can also serve as a drying treatment when volatilizing the diluting solvent or the like of the adhesive composition P.

When the heat treatment is performed, the heating temperature is preferably 50 to 150 ° C, particularly preferably 70 to 120 ° C. The heating time is preferably 30 seconds to 3 minutes, and particularly preferably 50 seconds to 2 minutes. Further, after the heat treatment, it is particularly preferable to provide a curing period of about 1 to 2 weeks at room temperature (for example, 23 ° C., 50% RH).

By the above heat treatment (and curing), the first (meth) acrylic acid ester copolymer (A) and the second (meth) acrylic acid ester copolymer (B) are subjected to the isocyanate-based cross-linking agent (C). Crosslink to form a three-dimensional network structure. In particular, since the second (meth) acrylic acid ester copolymer (B) has more cross-linking points, cross-linking between the second (meth) acrylic acid ester copolymers (B) occurs preferentially. It is presumed to be.

As described above, when the pressure-sensitive adhesive layer 3 is formed of an acrylic pressure-sensitive adhesive containing an antistatic agent, the pressure-sensitive adhesive layer 3 has excellent adhesion to the base material 2. As a result, the stability and reliability of the product are high, and there is no possibility that the pressure-sensitive adhesive layer 3 or the pressure-sensitive adhesive remains on the flexible device side when the carrier sheet 1 is peeled off from the flexible device.

(2-2) Thickness The thickness of the pressure-sensitive adhesive layer 3 is preferably 5 μm or more, particularly preferably 12 μm or more, and further preferably 17 μm or more. When the thickness of the pressure-sensitive adhesive layer 3 is 5 μm or more, good adhesiveness can be obtained. Further, if the thickness of the pressure-sensitive adhesive layer 3 is 12 μm or more, even if foreign matter such as dust or dirt adheres between the pressure-sensitive adhesive layer 3 (adhesive surface) of the carrier sheet 1 and the flexible device, the foreign matter is concerned. Is embedded in the pressure-sensitive adhesive layer 3. As a result, it is possible to suppress the occurrence of air biting due to foreign matter between the carrier sheet 1 and the flexible device, and to perform a light emission inspection or the like without any problem.

On the other hand, the thickness of the pressure-sensitive adhesive layer 3 is preferably 75 μm or less, particularly preferably 50 μm or less, and further preferably 30 μm or less from the viewpoint of peelability.

(2-3) Physical properties of the pressure-sensitive adhesive layer The pressure-sensitive adhesive layer when a voltage of 100 V is applied to the carrier sheet 1 obtained by peeling the release sheet 4 in an environment of 23 ° C. and a relative humidity of 50% for 10 seconds. The surface resistivity of the exposed surface (adhesive surface) of 3 is preferably 1 × 10 ¹¹ Ω / sq or less, particularly preferably 5 × 10 ¹⁰ Ω / s or less, and further preferably 1 × 10 11 Ω / sq or less as an upper limit value. × 10 It is preferably ¹⁰ Ω / s or less. By setting the upper limit value of the surface resistivity as described above, it is more effective to generate static electricity especially when the release sheet 4 is peeled from the carrier sheet 1 or when the carrier sheet 1 is peeled from the flexible device. It can be suppressed. The lower limit of the surface resistivity is not particularly limited, but is usually preferably 1 × 10 ⁷ Ω / sq or more, particularly preferably 5 × 10 ⁷ Ω / sq or more, and further 1 It is preferably × 10 ⁸ Ω / sq or more.

(3) Release sheet (3-1) Support The support 41 is not particularly limited as long as it does not adversely affect the pressure-sensitive adhesive layer 3, and is, for example, a polyethylene film, a polypropylene film, or a polybutene film. , Polybutadiene film, polymethylpentene film, polyvinyl chloride film, vinyl chloride copolymer film, polyethylene terephthalate film, polyethylene naphthalate film, polybutylene terephthalate film, polyurethane film, ethylene vinyl acetate film, ionomer resin film, ethylene. Meta) acrylic acid copolymer film, ethylene / (meth) acrylic acid ester copolymer film, polystyrene film, polycarbonate film, polyimide film, fluororesin film and the like are used. In addition, these crosslinked films are also used. Further, these laminated films may be used. Among the above, a polyethylene terephthalate film having excellent handleability is preferable.

The thickness of the support 41 is not particularly limited, but is usually preferably 15 to 100 μm, and particularly preferably 25 to 75 μm.

(3-2) Antistatic layer The second antistatic layer 42a and the third antistatic layer 42b are particularly limited as long as they are made of a material capable of imparting desired antistatic properties to the release sheet 4. Not done. As the material of the antistatic layers 42a and 42b, it is preferable to use the same material as the first antistatic layer 22 of the base material 2 described above. Further, the thickness of the antistatic layers 42a and 42b is preferably the same as that of the first antistatic layer 22 of the base material 2.

Here, as described above, in the carrier sheet 1 according to the present embodiment, either one of the second antistatic layer 42a and the third antistatic layer 42b can be omitted. However, when omitted, it is preferable to omit the third antistatic layer 42b. The presence of the second antistatic layer 42a in contact with the pressure-sensitive adhesive layer 3 can effectively enhance the antistatic property when the release sheet 4 is peeled from the pressure-sensitive adhesive layer 3.

(3-3) Release agent layer The release agent constituting the release agent layer 43 is not particularly limited, and any conventionally known release agent may be appropriately selected depending on the type of the pressure-sensitive adhesive in the pressure-sensitive adhesive layer 3. Can be used. Examples of such a release agent include silicone resin-based, fluororesin-based, alkyd resin-based, olefin resin-based, acrylic-based, long-chain alkyl group-containing compound-based, and rubber-based release agents. In particular, when the pressure-sensitive adhesive of the pressure-sensitive adhesive layer 3 is an acrylic pressure-sensitive adhesive, a silicone resin-based release agent is preferable from the viewpoint of the peelability of the pressure-sensitive adhesive layer 3. When the pressure-sensitive adhesive of the pressure-sensitive adhesive layer 3 is a silicone-based pressure-sensitive adhesive, the release agent layer 43 may be omitted.

The thickness of the release agent layer 43 is preferably 0.01 μm or more, particularly preferably 0.03 μm or more, and further preferably 0.05 μm or more as the lower limit value. When the lower limit of the thickness is the above, the function as the release agent layer 43 can be fully exhibited. The upper limit of the thickness of the release agent layer 43 is preferably 3 μm or less, particularly preferably 1 μm or less, and further preferably 0.5 μm or less. When the upper limit of the thickness is the above, it is possible to sufficiently cure the release agent layer 43.

(3-4) Physical Properties of the Release Sheet 4 The surface of the release sheet 4 on the adhesive layer 3 side when a voltage of 100 V is applied to the release sheet 4 for 10 seconds in an environment of 23 ° C. and a relative humidity of 50%. The surface resistivity of the exposed surface of the release agent layer 43) is preferably 1 × 10 ¹¹ Ω / sq or less, particularly preferably 5 × 10 ¹⁰ Ω / sq or less, and further preferably 1 × 10 11 Ω / sq or less as an upper limit value. × 10 It is preferably ¹⁰ Ω / sq or less. Since the upper limit of the surface resistivity is the above, it is possible to satisfactorily suppress the generation of static electricity when the release sheet 4 is peeled from the carrier sheet 1 (adhesive layer 3), and the carrier sheet 1 can be used. When attached to a flexible device, it is possible to more effectively prevent dust and dirt in the air from adhering to the device. The lower limit of the surface resistivity is not particularly limited, but is usually preferably 1 × 10 ⁷ Ω / sq or more, particularly preferably 5 × 10 ⁷ Ω / sq or more, and further 1 It is preferably × 10 ⁸ Ω / sq or more.

Further, in an environment of 23 ° C. and a relative humidity of 50%, when a voltage of 100 V is applied to the release sheet 4 for 10 seconds, the surface of the release sheet 4 opposite to the pressure-sensitive adhesive layer 3 (third charge). The surface resistivity of the exposed surface of the prevention layer 42b) is preferably 1 × 10 ¹¹ Ω / sq or less, particularly preferably 5 × 10 ¹⁰ Ω / sq or less, and further 1 × 10 11 Ω / sq or less as an upper limit value. It is preferably 10 ¹⁰ Ω / sq or less. When the upper limit value of the surface resistivity is the above, it is possible to more effectively suppress the generation of static electricity when the carrier sheet 1 is unwound from the winding roll of the carrier sheet 1. The lower limit of the surface resistivity is not particularly limited, but is usually preferably 1 × 10 ⁷ Ω / sq or more, particularly preferably 5 × 10 ⁷ Ω / sq or more, and further 1 It is preferably × 10 ⁸ Ω / sq or more.

2. 2. Method for Producing Carrier Sheet (1) Manufacture of Base Material In order to manufacture the base material 2 in the present embodiment, as an example, one surface of the base material film 21 contains a composition for an antistatic layer and, if desired, a solvent. After the coating liquid to be applied is applied, it is dried and cured to form the first antistatic layer 22.

The solvent is not particularly limited, and various solvents can be used. For example, an ether solvent, an alcohol solvent, a mixed solvent of an alcohol solvent and purified water, or the like is used.

The coating liquid for the antistatic layer composition may be applied by a conventional method, for example, by a gravure coating method, a bar coating method, a spray coating method, a spin coating method, a knife coating method, a roll coating method, a die coating method, or the like. Just do it.

After applying the coating liquid, it is preferable to heat and dry the coating film. The heating temperature for heat drying is preferably 70 to 140 ° C., and the heating time is preferably about 30 to 60 seconds.

(2) Production of Release Sheet In order to produce the release sheet 4 in the present embodiment, as an example, a composition for an antistatic layer and a coating liquid containing a solvent, if desired, are applied to one surface of the support 41. After that, it is dried and cured to form a second antistatic layer 42a. Further, the composition for the antistatic layer and, if desired, a coating liquid containing a solvent are applied to the other surface of the support 41, dried and cured to form the third antistatic layer 42b. The method for forming the antistatic layers 42a and 42b is the same as the method for forming the first antistatic layer 22 in the base material 2 described above.

Further, a release agent layer 43 is formed on the second antistatic layer 42a. The release agent layer 43 can be formed by applying a release agent coating liquid containing a release agent and, if desired, a solvent or the like, and then heating and drying as necessary. The method of applying the release agent coating liquid is the same as the method of applying the coating liquid of the antistatic layer.

(3) Manufacture of Carrier Sheet In order to manufacture the carrier sheet 1 according to the present embodiment, as an example, a pressure-sensitive adhesive composition and optionally A coating solution containing a diluent is applied and heat-treated to crosslink the adhesive composition to form a coating layer. Next, the release sheet 4 is attached to the coating layer so that the release agent layer 43 is in contact with the coating layer. When the curing period is required, the curing period is set, and when the curing period is not required, the coating layer becomes the adhesive layer 3 as it is. As a result, the carrier sheet 1 is obtained. The conditions for heat treatment and curing are as described above.

As a method for applying the coating liquid of the adhesive composition, for example, a bar coating method, a knife coating method, a roll coating method, a blade coating method, a die coating method, a gravure coating method and the like can be used.

In the above production method, the coating liquid of the adhesive composition was applied to the base material 2, but the base material 2 may be applied to the release sheet 4 and then attached to the coating layer. ..

3. 3. Physical properties of the carrier sheet, etc. (1) Total thickness The total thickness of the laminated body (in this embodiment, the laminated body of the base material 2 and the adhesive layer 3) other than the release sheet 4 in the carrier sheet 1 according to the present embodiment is the lower limit. The value is preferably 75 μm or more, particularly preferably 100 μm or more, and further preferably 125 μm or more. When the lower limit of the total thickness is the above, the flexible device to which the carrier sheet 1 is attached can be easily transported. Further, even when an external force is applied to the carrier sheet 1 by a point load, the carrier sheet 1 is less likely to have dents and has excellent dent resistance. Therefore, the flexible device to which the carrier sheet 1 is attached can be satisfactorily protected.

On the other hand, the total thickness is preferably 300 μm or less, particularly preferably 250 μm or less, and further preferably 200 μm or less as the upper limit value. When the upper limit value of the total thickness is the above, the handleability of the carrier sheet 1 becomes good, and it is possible to prevent the cost from becoming excessive.

(2) The peeling sheet 4 was manually peeled from the pressure-sensitive adhesive layer 3 in the carrier sheet 1 according to the present embodiment at a peeling rate of 2.0 m / min in an environment of a peeling band voltage of 23 ° C. and a relative humidity of 50%. At this time, the electrostatic potential (peeling band voltage) at a position 2.0 cm from the exposed surface (adhesive surface) of the pressure-sensitive adhesive layer 3 measured 5 seconds after peeling is preferably 200 V or less, particularly 150 V or less. It is preferably 100 V or less, and more preferably 100 V or less. Since the peeling band voltage is as described above, static electricity is unlikely to be generated when the peeling sheet 4 is peeled from the adhesive layer 3, and dust and dirt in the air due to static electricity are effectively suppressed from adhering to the device. can do. The lower limit of the peeling band voltage is not particularly limited, but is preferably 0V. The details of the method for measuring the peeling zone voltage are as shown in the test examples described later.

Further, in an environment of 23 ° C. and a relative humidity of 50%, the peeling sheet 4 is manually peeled from the pressure-sensitive adhesive layer 3 in the carrier sheet 1 according to the present embodiment at a peeling rate of 2.0 m / min. The electrostatic potential (peeling band voltage) at a position 2.0 cm from the exposed surface on the adhesive layer 3 side of the peeling sheet 4 measured after 5 seconds is preferably 200 V or less, and particularly preferably 150 V or less. Further, it is preferably 100 V or less. Since the peeling band voltage is as described above, static electricity is unlikely to be generated when the peeling sheet 4 is peeled from the adhesive layer 3, and dust and dirt in the air due to static electricity are effectively suppressed from adhering to the device. can do. The lower limit of the peeling band voltage is not particularly limited, but is preferably 0 V.

(3) Adhesive strength The adhesive strength of the carrier sheet 1 according to the present embodiment to the soda lime glass is preferably 300 mN / 25 mm or less, particularly preferably 250 mN / 25 mm or less, and further 200 mN as an upper limit value. It is preferably / 25 mm or less. When the upper limit of the adhesive strength is the above, the peelability of the carrier sheet 1 from the flexible device becomes excellent. On the other hand, the lower limit of the adhesive strength is preferably 50 mN / 25 mm or more, particularly preferably 75 mN / 25 mm or more, and further preferably 100 mN / 25 mm or more. When the lower limit of the adhesive force is the above, the carrier sheet 1 attached to the flexible device is prevented from being unintentionally peeled off in each step.

The adhesive strength of the carrier sheet 1 according to the present embodiment to the polyethylene terephthalate film is preferably 300 mN / 25 mm or less, particularly preferably 250 mN / 25 mm or less, and further 200 mN / 25 mm or less as an upper limit value. Is preferable. When the upper limit of the adhesive strength is the above, the peelability of the carrier sheet 1 from the flexible device becomes excellent. On the other hand, the lower limit of the adhesive strength is preferably 50 mN / 25 mm or more, particularly preferably 75 mN / 25 mm or more, and further preferably 100 mN / 25 mm or more. When the lower limit of the adhesive force is the above, the carrier sheet 1 attached to the flexible device is prevented from being unintentionally peeled off in each step.

Here, the adhesive strength in the present specification basically refers to the adhesive strength measured by the 180-degree peeling method according to JIS Z0237: 2009, but the measurement sample is 25 mm wide and 100 mm long, and the measured sample is used. It is attached to the adherend, pressurized at 0.5 MPa and 50 ° C. for 20 minutes, left at normal pressure, 23 ° C. and 50% RH for 24 hours, and then at a peeling speed of 2.0 m / min. It shall be measured.

(4) Haze value The haze value of the laminate other than the release sheet 4 (in this embodiment, the laminate of the base material 2 and the pressure-sensitive adhesive layer 3) in the carrier sheet 1 according to the present embodiment is 8% or less. Is preferable, and particularly preferably 5% or less, and further preferably 2% or less. When the haze value is not more than the above, it is also suitable for the light emission inspection of the flexible OLED device. In the carrier sheet 1 according to the present embodiment, the base material 2, the pressure-sensitive adhesive layer 3, and the release sheet 4 each have antistatic properties, so that the amount of the antistatic agent used in the pressure-sensitive adhesive layer 3 is reduced and the pressure-sensitive adhesive is adhered. The haze value of the agent layer 3 can be suppressed to a low level. This makes it possible to achieve the low haze value as described above. The lower limit of the haze value is not particularly limited, and is particularly preferably 0%. Here, the haze value in the present specification is a value measured according to JIS K7136: 2000.

4. Applications As described above, the carrier sheet 1 according to the present embodiment is mainly used for transporting the flexible device while protecting the surface of the flexible device during processes such as processing, laminating, and inspection.

In order to use the carrier sheet 1 according to the present embodiment, first, the release sheet 4 is peeled from the pressure-sensitive adhesive layer 3, and the carrier sheet 1 (base material 2 and the pressure-sensitive adhesive layer) is passed through the exposed pressure-sensitive adhesive layer 3. 3) is attached to the flexible device to be transported. After that, the flexible device is subjected to processes such as processing, laminating, and inspection while being conveyed with the carrier sheet 1 attached. During these steps, the flexible device is prevented from being scratched on the surface due to the carrier sheet 1 being attached. When the above steps are completed and the carrier sheet 1 is no longer needed, the carrier sheet 1 is peeled off from the flexible device.

In the carrier sheet 1 according to the present embodiment, all of the base material 2, the pressure-sensitive adhesive layer 3, and the release sheet 4 have antistatic properties. Specifically, the base material 2 has a first antistatic layer 22, the pressure-sensitive adhesive layer 3 contains an antistatic agent, and the release sheet 4 has a second antistatic layer 42a and a third. It has at least one of the antistatic layers 42b of. As a result, the carrier sheet 1 exhibits excellent antistatic properties in each process. For example, during the feeding process of the carrier sheet 1, when the release sheet 4 is peeled off from the adhesive layer 3 and the carrier sheet 1 is attached to the flexible device, during the process of processing, laminating, inspecting, etc. of the flexible device, and the carrier sheet. When 1 is peeled off from the flexible device, static electricity is unlikely to be generated, and it is possible to prevent dust and dirt in the air from adhering to the flexible device due to static electricity. Further, in the carrier sheet 1 according to the present embodiment, the base material 2, the pressure-sensitive adhesive layer 3, and the release sheet 4 each have antistatic properties, so that the amount of the antistatic agent used in the pressure-sensitive adhesive layer 3 is reduced. be able to. As a result, the haze value of the pressure-sensitive adhesive layer 3 and, by extension, the haze value of the carrier sheet 1 as a whole can be suppressed to a low level. Therefore, the light emission inspection of the flexible OLED device or the like to which the carrier sheet 1 is attached can be satisfactorily performed.

The embodiments described above are described for facilitating the understanding of the present invention, and are not described for limiting the present invention. Therefore, each element disclosed in the above embodiment is intended to include all design changes and equivalents belonging to the technical scope of the present invention.

For example, a layer other than the first antistatic layer 22 may be further formed on the base film 21. Further, the release agent layer 43 of the release sheet 4 may be omitted, or layers other than the antistatic layers 42a and 42b and the release agent layer 43 may be further formed on the release sheet 4.

Hereinafter, the present invention will be described in more detail with reference to Examples and the like, but the scope of the present invention is not limited to these Examples and the like.

[Example 1]
1. 1. Manufacture of base material (formation of antistatic layer)
A diluted solution obtained by diluting a water-soluble hydroxyl group-containing polyester resin and PSS-doped PEDOT with dimethyl sulfoxide and water (manufactured by Chukyo Yushi Co., Ltd., product name "S-495", solid content 8.2% by mass). On the other hand, a melamine compound solution consisting of water-soluble methylol melamine and water (manufactured by Chukyo Oil & Fat Co., Ltd., product name "P-795", solid content 70.0% by mass), and leveling consisting of a surfactant and water as a leveling agent. An aqueous solution of the agent (manufactured by Chukyo Oil & Fat Co., Ltd., product name "R-438", solid content 10.0% by mass) is mixed, and a mixed solvent of water and isopropyl alcohol (mass ratio 1: 1) is further added thereto. , Diluted to a solid content of 0.6% by mass to obtain a coating liquid for the antistatic layer composition.

On one side (the side opposite to the adhesive layer side) of a polyethylene terephthalate (PET) film as a base film (manufactured by Mitsubishi Plastics, product name "PET125T-100", thickness: 125 μm, containing filler) After applying the coating liquid of the antistatic layer composition with a knife coater, it is heat-treated at 130 ° C. for 60 seconds to form a first antistatic layer having a thickness of 50 nm, and the first antistatic layer / A substrate made of a substrate film was obtained.

2. 2. Preparation of coating liquid for adhesive composition 2-1. Process (1)
Prepare 100 parts by mass of the mixed solution (a) of 68.04 parts by mass of 2-ethylhexyl acrylate, 30.46 parts by mass of butyl acrylate, 0.23 parts by mass of 4-hydroxybutyl acrylate and 1.27 parts by mass of acrylic acid. Then, 40 parts by mass thereof was separated and copolymerized by a solution polymerization method to prepare a first (meth) acrylic acid ester copolymer (A). When the molecular weight of the polymer (A) was measured by gel permeation chromatography (GPC) described later, the weight average molecular weight (Mw) was 180,000. The conversion rate at this time (a value obtained by dividing the mass of the copolymer obtained by polymerizing the monomers by the total mass of the monomers used as the raw material) was 80%.

2-2. Process (2)
65.25 parts by mass of 2-ethylhexyl acrylate, 12.99 parts by mass of butyl acrylate, 16.23 parts by mass of acrylic acid ester containing an ethylene oxide chain (average number of moles added = 9 mol) having a methoxy terminal, 4-hydroxy acrylate. A mixed solution (b) of 4.72 parts by mass of butyl and 0.81 parts by mass of acrylic acid was prepared, and 60 parts by mass thereof was separated from the copolymer (1) obtained by the above step (1). It was added to the solution containing A) and copolymerized with the monomer remaining during the polymerization of the first (meth) acrylic acid ester copolymer (A). After that, when a part of the solution was measured using GPC, it was confirmed that there was almost no change in the peak top of the weight average molecular weight of 180,000 of the above-mentioned copolymer (A), and the process was performed from the result of this GPC measurement. By subtracting the result of the GPC measurement in (1), the formation of the copolymer (B) having a weight average molecular weight of 15,000 was newly confirmed. Here, the compounding ratio of the copolymer (A) and the copolymer (B) is a mass ratio of 32:68 because the conversion rate in the above step (1) was 80%.

2-3. Process (3)
100 parts by mass of the acrylic polymer solution obtained in the above step (2) in terms of solid content was separated and diluted with methyl ethyl ketone so as to have a solid content concentration of 20% by mass. Then, as the isocyanate-based cross-linking agent (C), 3.5 parts by mass (representing a solid content conversion value) of an isocyanurate-type trimer of 1,6-hexamethylene diisocyanate (manufactured by Nippon Polyurethane Industry Co., Ltd., trade name "Coronate HX"). The same shall apply hereinafter.), And as the antistatic agent (D), 2.0 parts by mass of N-octyl-4-methylpyridinium hexafluorophosphate and potassium bis (fluorosulfonyl) imide (manufactured by Mitsubishi Materials Denshi Kasei Co., Ltd.) The coating liquid of the adhesive composition was obtained by adding 1.0 part by mass of the name "K-FSI") and 1.0 part by mass of tributyl acetylcitrate as a plasticizing agent and sufficiently stirring the mixture.

Here, the above-mentioned weight average molecular weight is a standard polystyrene-equivalent weight average molecular weight measured under the following conditions (GPC measurement) using gel permeation chromatography (GPC).
<Measurement conditions>
-GPC measuring device: HLC-8020 manufactured by Tosoh Corporation
-GPC column (passed in the following order): TSK guard volume HXL-H manufactured by Tosoh Corporation
TSK gel GMHXL (x2)
TSK gel G2000HXL
・ Measurement solvent: Tetrahydrofuran ・ Measurement temperature: 40 ° C

3. 3. Manufacture of release sheet On one surface of a polyethylene terephthalate film (manufactured by Mitsubishi Plastics, product name "PET25T-100", thickness: 25 μm) as a support, a second antistatic layer described above was used in the same manner as the first antistatic layer. An antistatic layer was formed, and a third antistatic layer was formed on the other surface in the same manner as the first antistatic layer described above.

On the other hand, a silicone-based release agent (manufactured by Shin-Etsu Chemical Co., Ltd.) and a curing catalyst (manufactured by Shin-Etsu Chemical Co., Ltd.) were mixed and diluted with toluene to prepare a coating liquid for the release agent layer. The obtained coating liquid was uniformly applied onto the second antistatic layer with a Meyer bar and then dried at 100 ° C. for 30 seconds to form a release agent layer having a thickness of 0.1 μm. In this way, a release sheet having a structure of a release agent layer / a second antistatic layer / a support / a third antistatic layer was obtained.

4. Manufacture of Carrier Sheet After applying the coating liquid of the adhesive composition obtained in the above step 2 to the surface of the base material obtained in the above step 1 on the side where the first antistatic layer does not exist, using a knife coater. Heat treatment was performed at 90 ° C. for 1 minute to form a pressure-sensitive adhesive layer having a thickness of 25 μm. Next, the release sheet obtained in the above step 3 was attached to the pressure-sensitive adhesive layer so that the release agent layer of the release sheet was in contact with the pressure-sensitive adhesive layer to obtain a carrier sheet.

[Examples 2 to 7, Comparative Example 1]
A carrier sheet was produced in the same manner as in Example 1 except that the base film, the pressure-sensitive adhesive layer, and the release sheet were changed to those shown in Table 1. As the release sheet of Example 3, a sheet having an antistatic layer only on the adhesive layer side was used. As the base film of Example 4, a polyethylene terephthalate film (manufactured by Toray Industries, Inc., product name “PET75U48”, thickness: 75 μm, no filler) was used. As the release sheet of Example 6, a sheet having no antistatic layer on the adhesive layer side was used. As the base film of Example 7, a polyethylene terephthalate film (manufactured by Mitsubishi Plastics, product name “T100F38”, thickness: 38 μm, containing filler) was used. As the adhesive composition of Comparative Example 1, the same adhesive composition as that of Example 1 was used except that it did not contain an antistatic agent.

[Test Example 1] (Measurement of surface resistivity)
The surface of the base material used in Examples and Comparative Examples on the side opposite to the adhesive layer side (carrier sheet surface side), the adhesive surface of the adhesive layer exposed by peeling the release sheet from the carrier sheet, and the release sheet. The surface resistivity of the surface on the pressure-sensitive adhesive layer side and the surface on the opposite side (the back surface side of the carrier sheet) was measured according to JIS K6911. Specifically, in an environment of 23 ° C. and a relative humidity of 50%, a resistivity measuring instrument (manufactured by Mitsubishi Analytech Co., Ltd., product name "Highresta UP MCP-HT450 type") is used to remove the substrate and release sheet. The surface resistivity (Ω / sq) of each surface after applying a voltage of 100 V to the peeled carrier sheet (base material + pressure-sensitive adhesive layer) or the peeled sheet (100 mm × 100 mm) for 10 seconds was measured. The results are shown in Table 1. The surface resistivity of the release sheet used in Example 3 on the back surface side of the carrier sheet, the surface resistivity of the release sheet used in Example 6 on the pressure-sensitive adhesive layer side, and the pressure-sensitive adhesive layer in the carrier sheet of Comparative Example 1. The surface resistivity of the adhesive surface exceeded the measurement limit in each case.

[Test Example 2] (Measurement of haze value)
The haze value (%) of the base material used in Examples and Comparative Examples was measured using a haze meter (manufactured by Nippon Denshoku Kogyo Co., Ltd., product name “NDH7000”) according to JIS K7136: 2000. The results are shown in Table 1. Further, the release sheet was peeled off from the carrier sheets produced in Examples and Comparative Examples, and the haze value (%) of the obtained laminate was measured in the same manner. The results are shown in Table 2.

[Test Example 3] (Peeling band voltage)
The carrier sheets produced in Examples and Comparative Examples were cut into 25 mm × 100 mm, and this was used as a sample. In an environment of 23 ° C and 50% relative humidity, the release sheet was manually peeled from the sample at a peeling rate of 2.0 m / min, and 5 seconds after the peeling, an electrostatic measuring instrument (manufactured by Simco Japan, product name "FMX"). -003 "), the electrostatic potential (peeling band voltage; V) at a position 2.0 cm from the exposed surface (adhesive surface) of the pressure-sensitive adhesive layer and the exposed surface of the peel-off sheet on the pressure-sensitive adhesive layer side. The electrostatic potential (peeling band voltage; V) at the position of 0 cm was measured. The results are shown in Table 2.

[Test Example 4] (Measurement of adhesive strength)
The release sheet is peeled off from the carrier sheets manufactured in Examples and Comparative Examples, and the exposed adhesive layer is attached to soda lime glass (manufactured by Central Glass Co., Ltd.), and then 0.5 MPa, 50 by an autoclave manufactured by Kurihara Seisakusho Co., Ltd. Pressurized at ° C for 20 minutes. Then, after leaving it for 24 hours under the conditions of 23 ° C. and 50% RH, the adhesive strength was set to a peeling speed of 2.0 m / min and a peeling angle of 180 degrees using a tensile tester (Tensilon manufactured by Orientec). (MN / 25 mm) was measured. Conditions other than those described here were measured in accordance with JIS Z 0237: 2009. The results are shown in Table 2.

In addition, the adhesive strength (mN / 25 mm) is the same as above, except that the adherend is changed to a polyethylene terephthalate (PET) film (manufactured by Toray Industries, Inc., product name "Lumirror 50T60", thickness 50 μm, fixed to a glass plate). Was measured. The results are shown in Table 2.

[Test Example 5] (Drilling test)
The carrier sheets produced in Examples and Comparative Examples were placed on a hard flat plate with the substrate side facing up. Then, using a durometer (manufactured by Polymer Meter Co., Ltd., product name "Asker rubber hardness tester C2 type", hemispherical shape with a diameter of 2.54 mm), a point load of 400 g is applied to the surface of the base material of the carrier sheet. It was applied for seconds and dented. One minute later, the dent depth was measured using an optical interference microscope (manufactured by Veeco, product name "surface shape measuring device WYKO NT110"). At this time, the measurement conditions were VSI, the magnification was 2.5 times, and the measurement range was 2.5 mm × 1.9 mm. The images and graphs acquired in the measurement are shown in FIG. 2 for reference. Based on the measurement results, the dent resistance was evaluated under the following evaluation criteria. The results are shown in Table 2.
⊚: dent depth is less than 0.5 μm ○: dent depth is 0.5 μm or more and less than 1.0 μm ×: dent depth is 1.0 μm or more

[Test Example 6] (Foreign matter embedding test)
A silicone resin filler (manufactured by Momentive, product name "Tospearl 145L", average particle size: 4.5 μm) was sprayed on a 7 cm × 7 cm soda lime glass plate in a very small amount and monodispersed. The release sheet was peeled off from the carrier sheets produced in Examples and Comparative Examples, and the exposed adhesive layer was attached onto the soda lime glass plate. Then, after autoclaving treatment under the conditions of 50 ° C. and 0.5 MPa for 20 minutes, the mixture was left at normal pressure at 23 ° C. and 50% RH for 24 hours, and this was used as a sample.

With respect to the obtained sample, whether or not the filler is embedded in the adhesive layer (whether or not there is air biting due to the filler) is visually observed from the carrier sheet side, and foreign matter embedding property is determined according to the following criteria. Was evaluated. The results are shown in Table 2.
○: The filler is sufficiently embedded in the adhesive layer △: Air is partially caught in ×: Air is caught in the whole

As is clear from Table 2, the carrier sheet produced in the examples is excellent in peeling antistatic property at least on the adhesive surface of the adhesive layer, and the haze value is suppressed to a low level. Further, the carrier sheets produced in Examples 1 to 3, 5 and 6 are also excellent in dent resistance. Further, the carrier sheets produced in Examples 1, 3, 4, and 6 are also excellent in foreign matter embedding property.

The carrier sheet for flexible devices according to the present invention is particularly suitable as a carrier sheet used in processes such as processing, laminating, and inspection of flexible OLED devices.

1 ... Carrier sheet for flexible devices 2 ... Base material 21 ... Base film 22 ... First antistatic layer 3 ... Adhesive layer 4 ... Release sheet 41 ... Support 42a ... Second antistatic layer 42b ... Third Antistatic layer 43 ... Release agent layer

Claims (9)

A carrier sheet for flexible devices for protecting and transporting flexible devices.
It is used for flexible devices in which the optical system inspection process is performed with the carrier sheet for flexible devices attached.
With the base material
The pressure-sensitive adhesive layer laminated on one surface side of the base material and
It is provided with a release sheet laminated on the surface of the pressure-sensitive adhesive layer opposite to the base material.
All of the base material, the pressure-sensitive adhesive layer, and the release sheet have antistatic properties.
The base material has a base film and an antistatic layer formed on one surface side of the base film.
The thickness of the base film is 50 μm or more and 188 μm or less .
The pressure-sensitive adhesive layer is formed of a pressure-sensitive adhesive composition containing a (meth) acrylic acid ester copolymer and an antistatic agent.
The content of the antistatic agent is 0.1 part by mass or more and 10 parts by mass or less with respect to 100 parts by mass of the (meth) acrylic acid ester copolymer.
A carrier sheet for flexible devices. The carrier sheet for a flexible device according to claim 1, wherein the pressure-sensitive adhesive layer is laminated on the base material so as to be located on the other side of the base film. The carrier sheet for a flexible device according to claim 1 or 2, wherein the pressure-sensitive adhesive layer contains an antistatic agent. The carrier for a flexible device according to any one of claims 1 to 3, wherein the release sheet has a support and an antistatic layer formed on at least one surface side of the support. Sheet. Surface resistance of the exposed surface of the pressure-sensitive adhesive layer when a voltage of 100 V is applied for 10 seconds to the carrier sheet for a flexible device formed by peeling the release sheet in an environment of 23 ° C. and a relative humidity of 50%. The carrier sheet for a flexible device according to any one of claims 1 to 4, wherein the rate is 1 × 10 ⁷ Ω / sq or more and 1 × 10 ¹¹ Ω / sq or less. In an environment of 23 ° C. and a relative humidity of 50%, the surface resistivity of the surface of the substrate opposite to the pressure-sensitive adhesive layer when a voltage of 100 V is applied to the substrate for 10 seconds is 1. The carrier sheet for a flexible device according to any one of claims 1 to 5, wherein the carrier sheet is x10 ⁷ Ω / sq or more and 1 × 10 ¹¹ Ω / sq or less. In an environment of 23 ° C. and a relative humidity of 50%, the surface resistivity of the surface on the pressure-sensitive adhesive layer side of the release sheet when a voltage of 100 V is applied to the release sheet for 10 seconds is 1 × 10 ⁷ . The carrier sheet for a flexible device according to any one of claims 1 to 6, wherein the carrier sheet is Ω / sq or more and 1 × 10 ¹¹ Ω / sq or less. In an environment of 23 ° C. and a relative humidity of 50%, the surface resistivity of the surface of the release sheet opposite to the pressure-sensitive adhesive layer when a voltage of 100 V is applied to the release sheet for 10 seconds is 1. The carrier sheet for a flexible device according to any one of claims 1 to 7, wherein the carrier sheet is x10 ⁷ Ω / sq or more and 1 × 10 ¹¹ Ω / sq or less. The carrier sheet for a flexible device according to any one of claims 1 to 8, wherein the carrier sheet for the flexible device excluding the release sheet has a haze value of 8% or less.

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