JP2024014618A - Method for manufacturing an adhesive sheet, method for manufacturing a laminate, and method for manufacturing an optical film with an adhesive sheet - Google Patents

Abstract

[Problem] To provide a technology suitable for manufacturing adhesive sheets with low environmental impact. The provided method for producing a pressure-sensitive adhesive sheet includes a first base sheet, a first coating layer containing a first photocurable composition, and a first release liner, which include a first base sheet, a first coating layer containing a first photocurable composition, and a first release liner in this order. Forming a first adhesive sheet from a first coating layer by irradiating the laminate with light, and using a first release liner peeled off from the first adhesive sheet as a second base sheet. A second laminate including a second base sheet, a second coating layer containing a second photocurable composition, and a second release liner in this order is irradiated with light to form a second base sheet. forming a second adhesive sheet from the coating layer. The second base sheet has a greater release force against the second adhesive sheet than the second release liner. [Selection diagram] Figure 1

Description

The present invention relates to a method for manufacturing an adhesive sheet, a method for manufacturing a laminate, and a method for manufacturing an optical film with an adhesive sheet.

Various image display devices, typified by liquid crystal display devices and electroluminescent (EL) display devices, generally include an optical laminate including an optical film such as a polarizing film and an adhesive sheet. Adhesive sheets are usually used for bonding between optical films included in an optical laminate and for bonding an optical laminate and an image display panel. A typical pressure-sensitive adhesive sheet is a sheet obtained by curing a group of monomers including acrylic monomers, silicone monomers, etc. by polymerization and crosslinking. Patent Document 1 discloses a method in which a laminate including a base sheet, a coating layer containing a photocurable composition, and a release liner in this order is irradiated with light to form a pressure-sensitive adhesive sheet from the coating layer. In this method, since both main surfaces of the coating layer are covered with the base sheet and the release liner, inhibition of the photocuring reaction by oxygen can be suppressed.

Japanese Patent Application Publication No. 2016-155981

Formation of a pressure-sensitive adhesive sheet by curing usually requires energy such as heat or light. According to a method that uses light (photocuring method), the energy required to form an adhesive sheet is lower than, for example, a method of thermally curing a coating layer containing an adhesive composition and a solvent in an oven (thermal curing method). The amount can be reduced. However, from the viewpoint of reducing the environmental load during the production of pressure-sensitive adhesive sheets, it is insufficient to focus only on the amount of energy required to cure the coating layer.

The present invention aims to provide a technology suitable for manufacturing pressure-sensitive adhesive sheets with low environmental impact.

The present invention
A first laminate including a first base sheet, a first coating layer containing a first photocurable composition, and a first release liner in this order is irradiated with light to perform the first coating. forming a first adhesive sheet from the layers;
A second coating comprising the second base sheet and a second photocurable composition formed using the first release liner peeled from the first adhesive sheet as a second base sheet. forming a second adhesive sheet from the second coating layer by irradiating a second laminate including a layer and a second release liner in this order with light,
The second base sheet has a greater release force with respect to the second adhesive sheet than the second release liner.
Method for manufacturing adhesive sheet,
I will provide a.

In another aspect, the invention provides:
A first laminate including a first base sheet, a first coating layer containing a first photocurable composition, and a first release liner in this order is irradiated with light to perform the first coating. forming a first adhesive sheet from the layers;
A second coating layer containing the second base sheet and a second photocurable composition, using the first release liner peeled from the first adhesive sheet as a second base sheet; and forming a second laminate including a second release liner in this order;
A method for manufacturing a laminate, including
I will provide a.

In another aspect, the invention provides:
A method for producing an optical film with a pressure-sensitive adhesive sheet, the method comprising forming an optical film with a pressure-sensitive adhesive sheet by disposing an optical film on the exposed surface of the pressure-sensitive adhesive sheet formed by the method for producing a pressure-sensitive adhesive sheet of the present invention;
I will provide a.

According to the present invention, it is possible to provide a technique suitable for manufacturing pressure-sensitive adhesive sheets with low environmental impact.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic diagram for explaining an example of a method for manufacturing a pressure-sensitive adhesive sheet of the present invention. 1 is a cross-sectional view schematically showing an example of a release liner that can be used in the method for producing a pressure-sensitive adhesive sheet of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic diagram for explaining an example of a method for manufacturing a pressure-sensitive adhesive sheet of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic diagram for explaining an example of a method for manufacturing a pressure-sensitive adhesive sheet of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic diagram for explaining an example of a method for manufacturing an optical film with a pressure-sensitive adhesive sheet of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic diagram for explaining an example of a method for manufacturing an optical film with a pressure-sensitive adhesive sheet of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic diagram for explaining an example of a method for manufacturing an optical film with a pressure-sensitive adhesive sheet of the present invention.

The method for manufacturing a pressure-sensitive adhesive sheet according to the first aspect of the present invention includes:
A first laminate including a first base sheet, a first coating layer containing a first photocurable composition, and a first release liner in this order is irradiated with light to perform the first coating. forming a first adhesive sheet from the layers;
A second coating comprising the second base sheet and a second photocurable composition formed using the first release liner peeled from the first adhesive sheet as a second base sheet. forming a second adhesive sheet from the second coating layer by irradiating a second laminate including a layer and a second release liner in this order with light,
The second base sheet has a greater release force with respect to the second adhesive sheet than the second release liner.

In the second aspect of the present invention, for example, in the method for manufacturing a pressure-sensitive adhesive sheet according to the first aspect,
The first laminate is irradiated with the light from the first release liner side.

In the third aspect of the present invention, for example, in the method for manufacturing a pressure-sensitive adhesive sheet according to the first or second aspect,
The second base sheet and the second release liner both include a release layer on the surface on the second coating layer side,
The release layer included in the second base sheet and the release layer included in the second release liner are layers formed from release agent compositions containing the same release agent as a main component. It is.

In the fourth aspect of the present invention, for example, in the method for manufacturing a pressure-sensitive adhesive sheet according to any one of the first to third aspects,
The peeling force between the second base sheet and the second adhesive sheet is greater than the peeling force between the first release liner and the first adhesive sheet.

In the fifth aspect of the present invention, for example, in the method for manufacturing a pressure-sensitive adhesive sheet according to any one of the first to fourth aspects,
The first photocurable composition and the second photocurable composition are the same composition.

In the sixth aspect of the present invention, for example, in the method for manufacturing a pressure-sensitive adhesive sheet according to any one of the first to fifth aspects,
The first photocurable composition and the second photocurable composition contain a monomer group containing a (meth)acrylic monomer and/or a partial polymer of the monomer group.

In the seventh aspect of the present invention, for example, in the method for manufacturing a pressure-sensitive adhesive sheet according to the sixth aspect,
The (meth)acrylic monomer includes a carboxyl group-containing monomer.

The method for manufacturing a laminate according to the eighth aspect of the present invention includes:
A first laminate including a first base sheet, a first coating layer containing a first photocurable composition, and a first release liner in this order is irradiated with light to perform the first coating. forming a first adhesive sheet from the layers;
A second coating layer containing the second base sheet and a second photocurable composition, using the first release liner peeled from the first adhesive sheet as a second base sheet; and forming a second laminate including a second release liner in this order;
include.

The method for producing an optical film with a pressure-sensitive adhesive sheet according to the ninth aspect of the present invention includes:
The method includes forming an optical film with a pressure-sensitive adhesive sheet by arranging an optical film on the exposed surface of the pressure-sensitive adhesive sheet formed by the method for manufacturing a pressure-sensitive adhesive sheet according to any one of the first to seventh aspects.

In the tenth aspect of the present invention, for example, in the method for producing an optical film with a pressure-sensitive adhesive sheet according to the ninth aspect,
The optical film includes at least one film selected from the group consisting of a polarizing film and a retardation film.

The present invention will be described in detail below, but the present invention is not limited to the following embodiments, and can be implemented with arbitrary modifications without departing from the gist of the present invention.

The present inventor came up with the idea of further reducing the environmental load in the manufacturing process of pressure-sensitive adhesive sheets by reusing the release liner, which had been discarded immediately after peeling. Based on this idea, the inventor proceeded with studies and developed the present invention. Completed. The release force of the release liner after being peeled off from the adhesive sheet is greater than that of the unused state. If a release liner with increased release strength is reused as a base sheet, the amount of release liner that is discarded can be reduced, and the environmental burden can be reduced.

[Method for manufacturing adhesive sheet]
An example of the method for manufacturing a pressure-sensitive adhesive sheet of the present invention will be described with reference to FIG. In this example, light 14A is applied to a first laminate 10 that includes a first base sheet 11A, a first coating layer 12A containing a first photocurable composition, and a first release liner 13A in this order. The first adhesive sheet 1A is formed from the first coating layer 12A by irradiation. The light 14A passes through the first release liner 13A, reaches the first coating layer 12A, and cures the first coating layer 12A. The formed first adhesive sheet 1A is sandwiched between the first base sheet 11A and the first release liner 13A until the first release liner 13A is peeled off to form a laminate (third laminate). ) 17. Next, the first release liner 13A is peeled off from the first adhesive sheet 1A. Using the peeled first release liner 13A as the second base sheet 11B, the second base sheet 11B, the second coating layer 12B containing the second photocurable composition, and the second release liner A second laminate 20 including liners 13B in this order is formed. The formed second laminate 20 is irradiated with light 14B to form a second adhesive sheet 1B from the second coating layer 12B. The light 14B passes through the second release liner 13B, reaches the second coating layer 12B, and cures the second coating layer 12B. The formed second adhesive sheet 1B is sandwiched between the second base sheet 11B and the second release liner 13B until the second release liner 13B is peeled off to form a laminate (fourth laminate). 27). The second base sheet 11B has a greater peeling force against the second adhesive sheet 1B than the second release liner 13B. The second release liner 13B may be the same as the first release liner 13A. The laminate 27 that satisfies the above relationship regarding the peeling force with respect to the second adhesive sheet 1B is suitable for stable peeling of the second release liner 13B.

The increase in the release force of the first release liner 13A is estimated to be due to the increase in the amount of functional groups and radicals present on the surface of the first release liner 13A on the side of the first coating layer 12A due to the irradiation with the light 14A. be done. The above increase is due to the fact that a chemical bond is generated between the first release liner 13A and the first adhesive sheet 1A by irradiation with the light 14A, and a part of the bond or a group formed by decomposition of the bond becomes the first adhesive. This may be caused by remaining on the above surface even after the sheet 1A is peeled off. The degree of increase in release force depends on, for example, the composition of the photocurable composition, the composition, formation conditions and thickness of the first adhesive sheet 1A to be formed, the material, thickness and release surface of the first release liner 13A. It may vary depending on the state and the composition, formation conditions, thickness, etc. of the release layer that the first release liner 13A may include.

By forming the second adhesive sheet 1B, the release force of the second release liner 13B also usually increases. Using the second release liner 13B peeled from the laminate 27 as a base sheet, adhesion is achieved by irradiating light onto the laminate including the base sheet, the coating layer containing the photocurable composition, and the release liner in this order. Formation of the sheet may be repeated.

(Release liner)
An example of the base material of the first release liner 13A (hereinafter referred to as "liner base material") is a resin film. Examples of resins that can be included in the liner base material are polyesters such as polyethylene terephthalate and polyethylene naphthalate, acetate resins, polyether sulfones, polycarbonates, polyamides, polyimides, polyolefins, (meth)acrylic resins, polyvinyl chloride, polyvinylidene chloride. , polystyrene, polyvinyl alcohol, polyarylate, and polyphenylene sulfide. The resin is preferably a polyester such as polyethylene terephthalate.

It is preferable that the first release liner 13A has excellent transparency for light 14A.

The thickness of the first release liner 13A is, for example, 10 to 200 μm, and may be 25 to 150 μm.

The first release liner 13A may include layers other than the liner base material. The first release liner 13A may include a release layer. The first release liner 13A shown in FIG. 2 includes a liner base material 131 and a release layer 132 formed on one surface of the liner base material 131. The first release liner 13A including the release layer 132 can be used such that the release layer 132 is on the side of the first coating layer 12A.

The release layer 132 is typically a cured layer of a release agent composition containing a release agent. Various mold release agents can be used as the mold release agent, such as a silicone mold release agent, a fluorine mold release agent, a long chain alkyl mold release agent, a fatty acid amide mold release agent, and silica powder. The first release liner 13A may include a cured layer of a release agent composition containing a silicone release agent as a main component (hereinafter referred to as "silicone release layer"). A silicone release layer is particularly suitable for achieving both adhesion and releasability to an acrylic pressure-sensitive adhesive sheet. In addition, in this specification, the main component means the component with the largest content rate.

The silicone mold release agent is, for example, various types of curable silicone materials such as addition reaction type, condensation reaction type, ultraviolet curable type, electron beam curable type, and solvent-free type, with addition reaction curable silicone materials being preferred. Addition reaction-curing silicone materials are particularly suitable for forming a release layer that has both adhesion and releasability to acrylic pressure-sensitive adhesive sheets. The curable silicone material may be a silicone-modified resin in which reactive silicone is introduced into an organic resin such as urethane, epoxy, or alkyd resin by graft polymerization or the like.

An example of an addition reaction-curable silicone material is a polyorganosiloxane having a vinyl group or an alkenyl group in the molecule. The addition reaction curable silicone material does not need to have a hydrosilyl group. Examples of alkenyl groups are 3-butenyl, 4-pentenyl, 5-hexenyl, 6-heptenyl, 7-octenyl, 8-nonenyl, 9-decenyl, 10-undecenyl, and 11-dodecenyl. It is the basis. Examples of polyorganosiloxanes include polyalkylalkylsiloxanes such as polydimethylsiloxane, polydiethylsiloxane, and polymethylethylsiloxane, polyalkylarylsiloxanes, and a plurality of Si atom-containing monomers such as poly(dimethylsiloxane-diethylsiloxane). It is a copolymer. The polyorganosiloxane is preferably polydimethylsiloxane.

A mold release agent composition containing a silicone mold release agent as a main component (hereinafter referred to as a "silicone mold release agent composition") usually contains a crosslinking agent. Examples of crosslinking agents are polyorganosiloxanes containing hydrosilyl groups. The crosslinking agent may have two or more hydrosilyl groups in one molecule.

The silicone mold release agent composition may also include a curing catalyst. An example of a curing catalyst is a platinum-based catalyst. Examples of platinum-based catalysts are chloroplatinic acid, olefin complexes of platinum, and olefin complexes of chloroplatinic acid. The amount of the platinum-based catalyst used is, for example, 10 to 1000 ppm (by weight, in terms of platinum) based on the total solid content of the composition.

The silicone mold release agent composition may also contain additives. Examples of additives are release control agents and adhesion promoters. Examples of release control agents are unreacted silicone resins, and more specific examples are organosiloxanes such as octamethylcyclotetrasiloxane, and MQ resins. The total amount of the peel control agent and adhesion improver used is, for example, 1 to 30% by weight based on the total solid content of the composition. Further examples of additives are fillers, antistatic agents, antioxidants, UV absorbers, plasticizers and colorants. The amount of further additives used is, for example, up to 10% by weight in total, based on the total solids content of the composition.

The silicone mold release agent composition may include an organic solvent. Examples of organic solvents include hydrocarbon solvents such as cyclohexane, n-hexane, and n-heptane; aromatic solvents such as toluene and xylene; ester solvents such as ethyl acetate and methyl acetate; ketone solvents such as acetone and methyl ethyl ketone. Solvent: Alcohol solvent such as methanol, ethanol, butanol. Two or more types of organic solvents may be included. The amount of organic solvent used is preferably 80 to 99.9% by weight of the silicone mold release agent composition.

The release layer 132 can be formed, for example, by heating and drying a coating film containing a release agent composition formed on the liner base material 131. Application of the release agent composition includes roll coating, kiss roll coating, gravure coating, reverse coating, roll brushing, spray coating, dip roll coating, bar coating, knife coating, air knife coating, curtain coating, lip coating, and die coating. Various coating methods can be applied. For example, hot air drying can be used for heating and drying. The heating temperature and time vary depending on the heat resistance of the liner base material, but are usually about 80 to 150°C and about 10 seconds to 10 minutes. If necessary, irradiation with active energy rays such as ultraviolet rays may be used in combination.

The thickness of the release layer 132 is, for example, 10 to 300 nm. The upper limit of the thickness may be 200 nm or less, 150 nm or less, 120 nm or less, 110 nm or less, 100 nm or less, less than 100 nm, 90 nm or less, 80 nm or less, 70 nm or less, less than 70 nm, or even 65 nm or less. The lower limit of the thickness may be 15 nm or more, 20 nm or more, 25 nm or more, 30 nm or more, 35 nm or more, 40 nm or more, 45 nm or more, or even 50 nm or more.

The first release liner 13A may be sheet-shaped or elongated.

Examples of the second release liner 13B are the same as those of the first release liner 13A, including preferred examples. However, regarding the second release liner 13B, the transmittance of the light 14A is read as the transmittance of the light 14B. A second release liner 13B including a release layer 132 can be used such that the release layer 132 is on the side of the second coating layer 12B.

(Base sheet)
An example of the first base sheet 11A is a resin film. The example of the resin contained in the first base sheet 11A is the same as the example of the resin that can be contained in the liner base material.

The first base sheet 11A may have a light 14A transmittance, and may have a light 14A transmittance comparable to that of the first release liner 13A.

The thickness of the first base sheet 11A is, for example, 10 to 200 μm, and may be 25 to 150 μm.

The first base sheet 11A may include a release layer on the surface facing the first coating layer 12A. Examples of the release layer that the first base sheet 11A can include and its manufacturing method are the same as the examples of the release layer that the first release liner 13A can include and its manufacturing method. Both the first release liner 13A and the first base sheet 11A may include a release layer. In this case, both mold release layers may be formed from mold release agent compositions containing the same mold release agent as a main component. Further, the thicknesses of both release layers may be different, and for example, the release layer included in the first base sheet 11A may be thicker.

As the first base sheet 11A, a sheet can usually be selected that has a greater peeling force with the first adhesive sheet 1A than the first release liner 13A.

The first base sheet 11A may be sheet-shaped or elongated.

The first base sheet 11A may be the first release liner 13A peeled from the first adhesive sheet 1A, or the second release liner 13B peeled from the second adhesive sheet 1B.

(Photocurable composition)
The first photocurable composition is a composition that can form the first adhesive sheet 1A from the first coating layer 12A by irradiation with the light 14A. The first photocurable composition includes, for example, a monomer group containing a (meth)acrylic monomer and/or a partial polymer of the monomer group. The content of the (meth)acrylic component in the first photocurable composition, that is, the (meth)acrylic monomer and its partial polymer, is 50% by weight or more, 60% by weight or more, or 70% by weight or more. , or even 80% by weight or more. In this case, an acrylic pressure-sensitive adhesive sheet containing a (meth)acrylic polymer and a crosslinked product thereof as main components can be formed. However, the first photocurable composition is not limited to the above example. In this specification, (meth)acrylic means acrylic and methacryl. (Meth)acrylate means acrylate and methacrylate.

An example of the (meth)acrylic monomer is a (meth)acrylic acid alkyl ester having an alkyl group having 1 to 20 carbon atoms in the side chain. The number of carbon atoms in the alkyl group may be 7 or less, 6 or less, 5 or less, or even 4 or less. The alkyl group may be linear or branched. Examples of (meth)acrylic acid alkyl esters are methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, isopropyl (meth)acrylate, n-butyl (meth)acrylate, s-butyl (meth)acrylate. , t-butyl (meth)acrylate, isobutyl (meth)acrylate, n-pentyl (meth)acrylate, isopentyl (meth)acrylate, n-hexyl (meth)acrylate, isohexyl (meth)acrylate, isoheptyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, n-octyl (meth)acrylate, isooctyl (meth)acrylate, n-nonyl (meth)acrylate, isononyl (meth)acrylate, n-decyl (meth)acrylate, isodecyl (meth)acrylate, n-dodecyl (meth)acrylate (lauryl (meth)acrylate), n-tridecyl (meth)acrylate, n-tetradecyl (meth)acrylate, pentadecyl (meth)acrylate, hexadecyl (meth)acrylate, heptadecyl (meth)acrylate and octadecyl (meth)acrylate. The (meth)acrylic acid alkyl ester may be n-butyl (meth)acrylate.

The content of (meth)acrylic acid alkyl ester in the monomer group is, for example, 40% by weight or more, 50% by weight or more, 60% by weight or more, 70% by weight or more, 80% by weight or more, 85% by weight or more, It may be 90% by weight or more, or even 95% by weight or more. In calculating the content, the weight of the partially polymerized product is converted to the weight of each monomer before polymerization.

The monomer group may include carboxyl group-containing monomers. The carboxyl group-containing monomer may be a (meth)acrylic monomer, or in other words, the (meth)acrylic monomer may include a carboxyl group-containing monomer. Examples of carboxyl group-containing monomers are (meth)acrylic acid, carboxyethyl (meth)acrylate, carboxypentyl (meth)acrylate, itaconic acid, maleic acid, fumaric acid and crotonic acid. The content of the carboxyl group-containing monomer in the monomer group is, for example, 10% by weight or less, 9% by weight or less, 8% by weight or less, 7% by weight or less, 6% by weight or less, 5.5% by weight or less. , and further may be 5% by weight or less. The lower limit of the content may be, for example, 0.1% by weight or more, 0.5% by weight or more, or even 1% by weight or more. The monomer group does not need to contain carboxyl group-containing monomers.

The monomer group may include a hydroxy group-containing monomer. The hydroxy group-containing monomer may be a (meth)acrylic monomer, or in other words, the (meth)acrylic monomer may include a hydroxy group-containing monomer. Examples of hydroxy group-containing monomers include 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, 6-hydroxyhexyl (meth)acrylate, They are 8-hydroxyoctyl (meth)acrylate, 10-hydroxydecyl (meth)acrylate, 12-hydroxylauryl (meth)acrylate, and (4-hydroxymethylcyclohexyl)-methyl acrylate. The hydroxy group-containing monomer is preferably 2-hydroxyethyl (meth)acrylate or 4-hydroxybutyl (meth)acrylate. The content of the hydroxy group-containing monomer in the monomer group is, for example, 5% by weight or less, 4% by weight or less, 3% by weight or less, 2% by weight or less, 1% by weight or less, 0.8% by weight or less. , 0.5% by weight or less, 0.3% by weight or less, 0.2% by weight or less, or even 0.1% by weight or less. The lower limit of the content may be, for example, 0.01% by weight or more, 0.03% by weight or more, and even 0.05% by weight or more. The monomer group does not need to contain hydroxy group-containing monomers.

In the first photocurable composition, each of the above-mentioned monomers may be contained as a partially polymerized product. The partial polymer may be either a homopolymer or a copolymer. The partial polymer can contribute to stable formation of the first coating layer 12A by appropriately increasing the viscosity of the photocurable composition.

The first photocurable composition usually contains a photopolymerization initiator. An example of the photopolymerization initiator is a photoradical generator that generates radicals using visible light and/or ultraviolet light having a wavelength shorter than 450 nm.

Examples of photopolymerization initiators include benzoin ethers such as benzoin methyl ether, benzoin isopropyl ether, and benzyl dimethyl ketal; substituted benzoin ethers such as anisole methyl ether; 2,2-diethoxyacetophenone, 2,2-dimethoxy-2- Substituted acetophenones such as phenylacetophenone; α-hydroxyalkylphenones such as 1-hydroxycyclohexyl-phenylketone; substituted alphaketols such as 2-methyl-2-hydroxypropiophenone; aromatic sulfonyl chlorides such as 2-naphthalenesulfonyl chloride; Photoactive oximes such as 1-phenyl-1,1-propanedione-2-(o-ethoxycarbonyl)-oxime; benzophenone, benzoylbenzoic acid, methyl benzoylbenzoate, 4-phenylbenzophenone, hydroxybenzophenone, acrylated benzophenone, Benzophenone compounds such as 4-benzoyl-4'-methyldiphenyl sulfide, 3,3',4,4'-tetra(t-butylperoxycarbonyl)benzophenone; thioxanthone, 2-chlorothioxanthone, 2-methylthioxanthone, isopropyl Thioxanthone compounds such as thioxanthone, 2,4-diisopropylthioxanthone, 2,4-diethylthioxanthone; 2,4,6-trichloro-s-triazine, 2-phenyl-4,6-bis(trichloromethyl)-s-triazine , 2-(p-methoxyphenyl)-4,6-bis(trichloromethyl)-s-triazine, 2-(p-tolyl)-4,6-bis(trichloromethyl)-s-triazine, 2-piperonyl- 4,6-bis(trichloromethyl)-s-triazine, 2,4-bis(trichloromethyl)-6-styryl-s-triazine, 2-(naphth-1-yl)-4,6-bis(trichloromethyl )-s-triazine, 2-(4-methoxy-naphth-1-yl)-4,6-bis(trichloromethyl)-s-triazine, 2,4-trichloromethyl-(piperonyl)-6-triazine, 2 , 4-trichloromethyl-(4'-methoxystyryl)-6-triazine and other triazine compounds; 1,2-octanedione, 1-[4-(phenylthio)-,2-(O-benzoyloxime)], Oxime ester compounds such as O-(acetyl)-N-(1-phenyl-2-oxo-2-(4'-methoxy-naphthyl)ethylidene) hydroxylamine; bis(2,4,6-trimethylbenzoyl)phenyl Phosphine compounds such as phosphine oxide and 2,4,6-trimethylbenzoyldiphenylphosphine oxide; Quinone compounds such as 9,10-phenanthrenequinone, camphorquinone, and ethyl anthraquinone; Borate compounds; Carbazole compounds; Imidazole compounds compounds; and titanocene compounds. The photocurable composition may contain one or more photopolymerization initiators.

The amount of the photopolymerization initiator in the first photocurable composition is, for example, 0.02 to 10 parts by weight, and 0.05 to 10 parts by weight, based on a total of 100 parts by weight of the monomer group and its partial polymer. It may be 5 parts by weight.

The first photocurable composition may contain a crosslinking agent. An example of a crosslinking agent is a polyfunctional monomer having two or more polymerizable functional groups in one molecule. The polyfunctional monomer may be a (meth)acrylic monomer. Examples of polyfunctional monomers include monomers having two or more C=C bonds in one molecule, and one or more C=C bonds in one molecule and one or more epoxy groups, aziridine groups, and oxazolines. It is a monomer having a polymerizable functional group such as a hydrazine group, a hydrazine group, or a methylol group. The polyfunctional monomer is preferably a monomer having two or more C═C bonds in one molecule.

Examples of crosslinking agents are (poly)ethylene glycol di(meth)acrylate, (poly)propylene glycol di(meth)acrylate, neopentyl glycol di(meth)acrylate, pentaerythritol di(meth)acrylate, pentaerythritol tri(meth)acrylate, ) acrylate, dipentaerythritol hexa(meth)acrylate, 1,2-ethylene glycol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, 1,9-nonanediol diacrylate (NDDA), 1, Polyfunctional acrylates (ester compounds of polyhydric alcohol and (meth)acrylic acid, etc.) such as 12-dodecanediol di(meth)acrylate, trimethylolpropane tri(meth)acrylate, and tetramethylolmethane tri(meth)acrylate; allyl (meth)acrylate, vinyl (meth)acrylate, divinylbenzene, epoxy acrylate, polyester acrylate, urethane acrylate, butyl di(meth)acrylate, and hexyl di(meth)acrylate. The polyfunctional monomer is preferably a polyfunctional acrylate, more preferably trimethylolpropane tri(meth)acrylate, hexanediol di(meth)acrylate, or dipentaerythritol hexa(meth)acrylate.

The blending amount of the crosslinking agent varies depending on the molecular weight, the number of functional groups, etc., but is, for example, 5 parts by weight or less, 3 parts by weight or less, 2 parts by weight or less, per 100 parts by weight of the monomer group and its partial polymer. The amount may be 1 part by weight or less, or even 0.5 part by weight or less. The lower limit of the blending amount is, for example, 0.01 part by weight or more, and may even be 0.05 part by weight or more.

The first photocurable composition may contain additives other than those mentioned above. Examples of additives are chain transfer agents, silane coupling agents, viscosity modifiers, tackifiers, plasticizers, softeners, anti-aging agents, fillers, colorants, antioxidants, surfactants, and antistatic agents. and an ultraviolet absorber.

The content of the solvent in the first photocurable composition is, for example, 5% by weight or less, 4% by weight or less, 3% by weight or less, 2% by weight or less, 1% by weight or less, and even 0.5% by weight. It may be the following. The first photocurable composition may be substantially free of solvent. "Substantially free of solvent" means that the content of solvents derived from additives etc. is, for example, 0.1% by weight or less, preferably 0.05% by weight or less, more preferably 0.01% by weight or less. The intention is to allow it.

The viscosity of the first photocurable composition is preferably 5 to 100 poise. The first photocurable composition having a viscosity within the above range is particularly suitable for forming the first coating layer 12A.

The second photocurable composition is a composition that can form the second adhesive sheet 1B from the second coating layer 12B by irradiation with the light 14B. Examples of the second photocurable composition are the same as those of the first photocurable composition, including preferred examples. The first photocurable composition and the second photocurable composition may be the same composition. Moreover, the same composition is used as the first photocurable composition and the second photocurable composition to form the same adhesive sheet as the first adhesive sheet 1A and the second adhesive sheet 1B. It's okay.

(First and second laminates and their formation)
For the first base sheet 11A and the first release liner 13A, a sheet having a relatively large peeling force with respect to the first adhesive sheet 1A and a sheet having a relatively small peeling force can be selected, respectively. In other words, the peeling force between the first base sheet 11A and the first adhesive sheet 1A may be greater than the peeling force between the first release liner 13A and the first adhesive sheet 1A.

Both the first base sheet 11A and the first release liner 13A may include a release layer on the surface facing the first coating layer 12A. At this time, the release layer included in the first base sheet 11A and the release layer included in the first release liner 13A were formed from release agent compositions containing the same release agent as a main component. It may be a layer, or it may be a layer formed from the same mold release agent composition. Moreover, the thickness of both mold release layers may be the same.

The first laminate 10 is, for example, formed by forming a first coating layer 12A on a first base sheet 11A (or a first release liner 13A), and then forming a first coating layer 12A on the formed first coating layer 12A. It can be formed by arranging the first release liner 13A (or the first base sheet 11A). Further, the photocurable composition is poured into the space between the first base sheet 11A and the first release liner 13A, which are held at a predetermined interval so that their main surfaces face each other, and applied to the first release liner. A laminate 10 may be formed.

The first laminate 10 may include an elongated first base sheet 11A, an elongated first coating layer 12A, and an elongated first release liner 13A. For example, it may be elongated. The elongated first laminate 10 is constructed by, for example, conveying a first base sheet 11A and a first release liner 13A that have been unwound from a roll, while forming a first coating layer 12A therebetween. You can get it.

The first laminate 10 may include further layers other than the first base sheet 11A, the first coating layer 12A, and the first release liner 13A. The further layer may be arranged on the side of the first base sheet 11A and/or the first release liner 13A opposite to the side of the first coating layer 12A. It is preferable that the first coating layer 12A is in contact with the first base sheet 11A and the first release liner 13A.

For the second release liner 13B, a sheet can be selected that has a smaller release force against the second adhesive sheet 1B than the second base sheet 11B. The same sheet as the first release liner 13A may be selected as the second release liner 13B.

The peeling force between the second base sheet 11B and the second adhesive sheet 1B may be greater than the peeling force between the first release liner 13A and the first adhesive sheet 1A.

Both the second base sheet 11B and the second release liner 13B may include a release layer on the surface facing the second coating layer 12B. At this time, the release layer included in the second base sheet 11B and the release layer included in the second release liner 13B were formed from release agent compositions containing the same release agent as a main component. It may be a layer, or it may be a layer formed from the same mold release agent composition. Moreover, the thickness of both mold release layers may be the same.

The second laminate 20 is, for example, formed by forming the second coating layer 12B on the second base sheet 11B (or second release liner 13B), and then forming the second coating layer 12B on the formed second coating layer 12B. It can be formed by arranging a second release liner 13B (or a second base sheet 11B). Further, a photocurable composition is poured into the space between the second base sheet 11B and the second release liner 13B, which are held at a predetermined interval so that their main surfaces face each other, and applied to the second release liner. A laminate 20 may be formed. The second base sheet 11B is used so that the surface that was on the first coating layer 12A side before peeling, for example, the surface on the release layer 132 side, becomes the second coating layer 12B side. It's okay.

The second laminate 20 may include an elongated second base sheet 11B, an elongated second coating layer 12B, and an elongated second release liner 13B. For example, it may be elongated. The elongated second laminate 20 is formed by, for example, conveying the second base sheet 11B and the second release liner 13B that have been unwound from the roll, while forming the second coating layer 12B between them. You can get it.

The second laminate 20 may include additional layers other than the second base sheet 11B, the second coating layer 12B, and the second release liner 13B. The further layer may be arranged on the side of the second base sheet 11B and/or the second release liner 13B opposite to the side of the second coating layer 12B. The second coating layer 12B is preferably in contact with the second base sheet 11B and the second release liner 13B.

Formation of the first coating layer 12A and the second coating layer 12B includes roll coating, kiss roll coating, gravure coating, reverse coating, roll brushing, spray coating, dip roll coating, bar coating, knife coating, and air knife coating. Various coating methods such as curtain coating, lip coating, and die coating can be applied.

The thickness of the first coating layer 12A and the second coating layer 12B can be adjusted depending on the desired thickness of the first adhesive sheet 1A and second adhesive sheet 1B, respectively, and is, for example, 5 to 100 μm. , 5 to 50 μm, 5 to 25 μm, or even 5 to 20 μm.

(Light irradiation)
The lights 14A and 14B are, for example, visible light or ultraviolet light having a wavelength shorter than 450 nm. The lights 14A and 14B may include light having a wavelength in the same region as the absorption wavelength of the photopolymerization initiator included in the photocurable composition. Light 14A, 14B obtained by cutting short wavelength light of 300 nm or less with a filter or the like may be used. Cutting short wavelength light is suitable for suppressing deterioration of the release liner caused by light 14A, 14B. The light source of the lights 14A and 14B is, for example, a light irradiation device including an ultraviolet irradiation lamp. Examples of UV irradiation lamps are ultraviolet LEDs, low pressure mercury lamps, medium pressure mercury lamps, high pressure mercury lamps, extra high pressure mercury lamps, metal halide lamps, xenon lamps, microwave excited mercury lamps, black light lamps, chemical lamps, germicidal lamps, and low pressure discharge mercury lamps. , an excimer laser. Two or more ultraviolet irradiation lamps may be combined. The light 14A and the light 14B may have the same spectrum and may be irradiated under the same irradiation conditions (irradiation intensity and cumulative light amount).

In the example of FIG. 1, the lights 14A and 14B each pass through the release liner to reach the coating layer and cure the coating layer. However, the irradiation with the lights 14A and 14B may be performed from the base sheet side, or from both sides of the release liner and the base sheet.

Irradiation of the lights 14A and 14B may be continuous or intermittent.

The irradiation intensity of the lights 14A and 14B is, for example, 1 to 20 mW/cm ² . The cumulative amount of light 14A and 14B for the first laminate 10 and the second laminate 20 is, for example, 100 to 5000 mJ/cm ² .

(Peeling)
The first release liner 13A is peeled off from the photocured laminate 17. The laminate 17 includes a first base sheet 11A, a first adhesive sheet 1A, and a first release liner 13A in this order. By the above peeling, a laminate (fifth laminate) 15 including the first base sheet 11A and the first adhesive sheet 1A is obtained.

The peeling force of the first release liner 13A to the first adhesive sheet 1A is, for example, 0.01 to 3N/50mm. The upper limit of the peeling force is 2N/50mm or less, 1.5N/50mm or less, 1N/50mm or less, 0.5N/50mm or less, 0.25N/50mm or less, 0.2N/50mm or less, and even 0.1N/50mm or less. It may be 50 mm or less. The lower limit of the peeling force may be 0.02 N/50 mm or more, 0.03 N/50 mm or more, and even 0.04 N/50 mm or more.

The peeling force of the first base sheet 11A with respect to the first adhesive sheet 1A is, for example, 0.05 to 10 N/50 mm. The upper limit of peeling force is 8N/50mm or less, 5N/50mm or less, 2.5N/50mm or less, 2N/50mm or less, 1N/50mm or less, 0.75N/50mm or less, 0.5N/50mm or less, 0.3N /50mm or less, or even 0.2N/50mm or less. The lower limit of the peeling force may be 0.07 N/50 mm or more, 0.1 N/50 mm or more, and even 0.2 N/50 mm or more.

The peeled first release liner 13A may be wound into a rolled body and then reused as the second base sheet 11B.

The second release liner 13B may be peeled off from the photocured laminate 27. The laminate 27 includes a second base sheet 11B, a second adhesive sheet 1B, and a second release liner 13B in this order. By the above peeling, a laminate (sixth laminate) 25 including the second base sheet 11B and the second adhesive sheet 1B is obtained.

The peeling force of the second release liner 13B to the second adhesive sheet 1B is, for example, 0.01 to 3N/50mm. The upper limit of the peeling force is 2N/50mm or less, 1.5N/50mm or less, 1N/50mm or less, 0.5N/50mm or less, 0.25N/50mm or less, 0.2N/50mm or less, and even 0.1N/50mm or less. It may be 50 mm or less. The lower limit of the peeling force may be 0.02 N/50 mm or more, 0.03 N/50 mm or more, or even 0.04 N/50 mm or more.

The peeling force of the second base sheet 11B with respect to the second adhesive sheet 1B is, for example, 0.05 to 10 N/50 mm. The upper limit of peeling force is 8N/50mm or less, 5N/50mm or less, 2.5N/50mm or less, 2N/50mm or less, 1N/50mm or less, 0.75N/50mm or less, 0.5N/50mm or less, 0.3N /50mm or less, or even 0.2N/50mm or less. The lower limit of the peeling force may be 0.07 N/50 mm or more, 0.1 N/50 mm or more, and even 0.2 N/50 mm or more.

The ratio β/α of the peeling force β of the second base sheet 11B to the second adhesive sheet 1B to the peeling force α of the first release liner 13A to the first adhesive sheet 1A is 1.05 or more, 1 It may be .1 or more, 1.3 or more, or even 1.5 or more. The upper limit of the ratio β/α is, for example, 40 or less, 35 or less, 30 or less, 25 or less, 20 or less, 15 or less, 10 or less, 5 or less, 4 or less, 3 or less, 2 or less, and even 1.8 or less. It may be.

The peel force of the release liner and base sheet against the adhesive sheet is determined by cutting out a laminate containing the adhesive sheet, release liner and/or base sheet to a width of 50 mm to prepare a test piece, and using the prepared test piece to determine whether the release liner or base sheet Evaluation can be performed by conducting a 180° peeling test in which only the base sheet is peeled off. The peel test is carried out after approximately 0.5 to 1 hour has elapsed from the formation of the adhesive sheet. From the formation of the adhesive sheet to the implementation of the peel test, the laminate and test piece are placed in an atmospheric atmosphere at 23°C ± 5°C. The peeling speed of the peeling test is 300 mm/min, and the test temperature is 23°C±5°C. If the width of the laminate is less than 50 mm, the measured value at the original width may be converted to a value per 50 mm width. If the direction in which the coating layer containing the photocurable composition is formed can be determined, the TD perpendicular to the MD, which is the direction, can be determined as the width direction of the test piece. When the release liner and/or base sheet is elongated, the width direction thereof can be the width direction of the test piece.

The peeled second release liner 13B may be reused as a base sheet, or may be reused after being wound into a rolled body.

(adhesive sheet)
The thickness of the first adhesive sheet 1A and the second adhesive sheet 1B is, for example, 2 to 70 μm, 2 to 50 μm, 5 to 40 μm, 10 to 30 μm, 10 to 25 μm, or even 10 to 20 μm. good.

The polymerization rate of the monomer group in the first adhesive sheet 1A and the second adhesive sheet 1B is preferably 90% or more. The polymerization rate may be 95% or more, 98% or more, or even 99% or more.

The gel fraction of the first adhesive sheet 1A and the second adhesive sheet 1B is, for example, 50% or more, and may be 75% or more, 80% or more, or even 85% or more.

The same adhesive sheet may be formed as the first adhesive sheet 1A and the second adhesive sheet 1B.

The first adhesive sheet 1A and the second adhesive sheet 1B can be used, for example, in an optical laminate including an optical film. In other words, the first adhesive sheet 1A and the second adhesive sheet 1B may be used for optical laminates. The optical laminate may be an optical film with an adhesive sheet. However, the uses of the first adhesive sheet 1A and the second adhesive sheet 1B are not limited to the above example.

Another example of the method for manufacturing a pressure-sensitive adhesive sheet of the present invention will be described with reference to FIG. In this example, the first coating layer 12A is formed on one side of the elongated first base sheet 11A fed out from the roll 31 using the coating device 32. Next, the elongated first release liner 13A unwound from the rolled body 33A is placed on the first coating layer 12A to form the elongated first laminate 10. Next, the first laminate 10 is irradiated with light 14A from the light irradiation device 34 to form a long first adhesive sheet 1A. Next, the first release liner 13A is peeled off from the laminate 17 including the first adhesive sheet 1A and wound up into a roll 35A. The rolled-up first release liner 13A is reused as the second base sheet 11B. The above steps are performed while conveying the first base sheet 11A and the first release liner 13A. The laminate 15 formed by peeling off the first release liner 13A can be used, for example, for producing an optical film with an adhesive sheet or the same.

Next, the second coating layer 12B is formed by the coating device 32 on one side of the elongated second base sheet 11B fed out from the rolled body 35A. Next, the elongated second release liner 13B unwound from the rolled body 33B is placed on the second coating layer 12B to form the elongated second laminate 20. Next, the second laminate 20 is irradiated with light 14B from the light irradiation device 34 to form a long second adhesive sheet 1B. Next, the second release liner 13B is peeled off from the laminate 27 including the second adhesive sheet 1B and wound up into a roll 35B. The above steps are performed while conveying the second base sheet 11B and the second release liner 13B. The laminate 25 formed by peeling off the second release liner 13B can be used, for example, for producing an optical film with a pressure-sensitive adhesive sheet or the like. The method of FIG. 3 is particularly suitable for mass production of adhesive sheets.

Another example of the method for manufacturing a pressure-sensitive adhesive sheet of the present invention will be described with reference to FIG. 4. This example is the same as the example in FIG. 3, except that the first release liner 13A peeled off from the laminate 17 is reused for the second base sheet 11B without being wound up into the roll 35A. be. The method of FIG. 4 is particularly suitable for mass production of adhesive sheets.

[Release liner]
According to an aspect different from the above, the present invention provides a release liner used in the method for producing a pressure-sensitive adhesive sheet of the present invention. Examples of the release liner are the same as those described above in the description of the method for producing the pressure-sensitive adhesive sheet.

[Method for manufacturing laminate]
According to a different aspect from the above, the present invention includes:
Irradiating light 14A to a first laminate 10 including a first base sheet 11A, a first coating layer 12A containing a first photocurable composition, and a first release liner 13A in this order, Forming a first adhesive sheet 1A from the first coating layer 12A;
Using the first release liner 13A peeled from the first adhesive sheet 1A as the second base sheet 11B, the second coating layer containing the second base sheet 11B and the second photocurable composition is formed. 12B and a second release liner 13B in this order, forming a second laminate 20;
Provided is a method for manufacturing a laminate including: Examples of each layer and photocurable composition included in the first laminate 10 and second laminate 20, examples of lights 14A and 14B (including irradiation conditions), and first adhesive sheet 1A and second laminate 20 The example of the adhesive sheet 1B is the same as the example mentioned above in the explanation of the method of manufacturing the adhesive sheet.

[Method for manufacturing optical film with adhesive sheet]
An example of the method for producing an optical film with a pressure-sensitive adhesive sheet of the present invention will be described with reference to FIG. In this example, a first release liner 13A is formed by peeling off a first release liner 13A from a laminate 17 including a first base sheet 11A, a first adhesive sheet 1A, and a first release liner 13A in this order. The optical film 2 is placed on the exposed surface 18 of the adhesive sheet 1A to form an optical film 41 with an adhesive sheet. The optical film with adhesive sheet 41 includes a first base sheet 11A, a first adhesive sheet 1A, and an optical film 2 in this order. The optical film 41 with adhesive sheet can be used as it is or after peeling off the first base sheet 11A, for example, as an optical laminate including the first adhesive sheet 1A and the optical film 2 in an image display device or the like. The optical laminate may be bonded to an object (for example, an image forming panel) via the first adhesive sheet 1A. However, the use of the adhesive sheet-attached optical film 41 is not limited to the above example. Further members such as an optical film may be arranged on the exposed surface 18 formed by peeling off the first base sheet 11A from the optical film 41 with adhesive sheet. An optical film with adhesive sheet 42 including the adhesive sheet 1A and the optical film 2B in this order can be formed (see FIG. 6). The optical films 2A and 2B may be the same or different from each other.

The second adhesive sheet 1B is formed by peeling the second release liner 13B from the laminate 27 including the second base sheet 11B, the second adhesive sheet 1B, and the second release liner 13B in this order. An optical film with an adhesive sheet can also be formed by arranging the optical film 2 on the exposed surface 18 of the adhesive sheet. Further, the second base sheet 11B may be peeled off to form an optical film with an adhesive sheet including the optical film 2A, the second adhesive sheet 1B, and the optical film 2B in this order.

The optical film 2 may be placed on the exposed surface 18 directly or indirectly. In other words, the optical film 2 may be placed in contact with the exposed surface 18, or may be placed with another layer sandwiched between it and the exposed surface 18.

Another example of the method for producing an optical film with a pressure-sensitive adhesive sheet of the present invention will be described with reference to FIG. In this example, the long optical film 2 is placed on the exposed surface 18 of the first adhesive sheet 1A in the laminate 15 formed by the method of FIG. Form. The optical film 2 is unwound from the roll 36 and placed on the exposed surface 18. As shown in FIG. 7, the formation of the adhesive sheet and the formation of the optical film with the adhesive sheet may be performed continuously. The method shown in FIG. 7 is particularly suitable for mass production of optical films with adhesive sheets. An optical film with an adhesive sheet may be formed by similarly arranging the optical film 2 on the laminate 25 formed by the method shown in FIG.

The optical film 2 is, for example, a film containing at least one selected from the group consisting of a polarizing film and a retardation film. The optical film 2 may be a laminated film including a polarizing film and/or a retardation film. The optical film 2 may include a glass film. However, the optical film 2 is not limited to the above example.

A polarizing film includes a polarizer. A polarizing film typically includes a polarizer and a protective film (transparent protective film). The protective film is placed, for example, in contact with the main surface (the surface with the widest area) of the polarizer. A polarizer may be placed between two protective films. The protective film may be placed on at least one surface of the polarizer.

The polarizer is not particularly limited, and examples include hydrophilic polymer films such as polyvinyl alcohol films, partially formalized polyvinyl alcohol films, partially saponified ethylene/vinyl acetate copolymer films, iodine, and dichroism. Examples include those obtained by adsorbing dichroic substances such as dyes and uniaxially stretched; polyene-based oriented films such as dehydrated polyvinyl alcohol and dehydrochloric acid treated polyvinyl chloride. A polarizer typically consists of a polyvinyl alcohol film (polyvinyl alcohol films include partially saponified ethylene/vinyl acetate copolymer films) and a dichroic substance such as iodine.

The thickness of the polarizer is not particularly limited, and may be, for example, 80 μm or less, 50 μm or less, 30 μm or less, 25 μm or less, or even 20 μm or less. The lower limit of the thickness of the polarizer is not particularly limited, and may be, for example, 1 μm or more, 5 μm or more, 10 μm or more, or even 15 μm or more. A thin polarizer (for example, 20 μm or less in thickness) has suppressed dimensional changes and can contribute to improving the durability of the optical laminate, especially the durability under high temperatures.

As a material for the protective film, for example, a thermoplastic resin having excellent transparency, mechanical strength, thermal stability, moisture barrier properties, isotropy, etc. is used. Specific examples of such thermoplastic resins include cellulose resins such as triacetylcellulose, polyester resins, polyethersulfone resins, polysulfone resins, polycarbonate resins, polyamide resins, polyimide resins, polyolefin resins, (meth)acrylic resins, and cyclic resins. Examples include polyolefin resins (norbornene resins), polyarylate resins, polystyrene resins, polyvinyl alcohol resins, and mixtures thereof. The material of the protective film may be a thermosetting resin or an ultraviolet curing resin such as (meth)acrylic, urethane, acrylic urethane, epoxy, or silicone. When the polarizing film has two protective films, the materials of the two protective films may be the same or different. For example, a protective film made of a thermoplastic resin is bonded to one main surface of a polarizer via an adhesive, and a protective film made of a thermosetting resin or ultraviolet curable resin is attached to the other main surface of the polarizer. A protective film made of molded resin may be attached. The protective film may contain one or more types of arbitrary additives. Examples of additives include ultraviolet absorbers, antioxidants, lubricants, plasticizers, mold release agents, color inhibitors, flame retardants, nucleating agents, antistatic agents, pigments, colorants, and the like.

The thickness of the protective film can be determined as appropriate, but is generally about 10 to 200 μm from the viewpoint of strength, workability such as handling, thin film properties, etc.

The polarizer and the protective film are usually in close contact with each other via a water-based adhesive or the like. Examples of water-based adhesives include isocyanate adhesives, polyvinyl alcohol adhesives, gelatin adhesives, vinyl latex, water-based polyurethanes, and water-based polyesters. Examples of adhesives other than the above adhesives include ultraviolet curable adhesives and electron beam curable adhesives. Electron beam-curable adhesives for polarizing plates exhibit suitable adhesion to various types of protective films. The adhesive may include a metal compound filler.

In the polarizing film, a retardation film or the like may be formed on the polarizer instead of the protective film. It is also possible to provide another protective film, a retardation film, etc. on the protective film.

Regarding the protective film, a hard coat layer may be provided on the surface opposite to the surface bonded to the polarizer, and treatments for the purpose of anti-reflection, anti-sticking, diffusion, anti-glare, etc. can also be applied. .

The polarizing film may be a circularly polarizing film.

As the retardation film, one obtained by stretching a polymer film or one obtained by aligning and fixing a liquid crystal material can be used. The retardation film has, for example, birefringence in the plane and/or in the thickness direction.

The retardation film includes a retardation film for antireflection (see JP-A-2012-133303 [0221], [0222], and [0228]) and a retardation film for viewing angle compensation (see JP-A 2012-133303 [0221], [0222], and [0228]). 0225], [0226]), an obliquely oriented retardation film for viewing angle compensation (see JP-A-2012-133303 [0227]), and the like.

The specific structure of the retardation film, for example, retardation value, arrangement angle, three-dimensional birefringence, single layer or multilayer, etc., is not particularly limited, and any known retardation film can be used.

The thickness of the retardation film is preferably 20 μm or less, more preferably 10 μm or less, still more preferably 1 to 9 μm, particularly preferably 3 to 8 μm.

The retardation film may include, for example, a quarter-wave plate and/or a half-wave plate in which a liquid crystal material is oriented and fixed.

An image display device may be formed using an optical film with a pressure-sensitive adhesive sheet formed by the above manufacturing method. The image display device can be formed by, for example, joining optical films 41 and 42 with adhesive sheets and an image display panel. The bonding may be performed using the first adhesive sheet 1A or the second adhesive sheet 1B. The image display device may be an organic EL display or a liquid crystal display. However, the image display device is not limited to the above example. The image display device may be an electroluminescence (EL) display, a plasma display (PD), a field emission display (FED), or the like. The image display device can be used for household appliances, in-vehicle applications, public information displays (PID), and the like.

Hereinafter, the present invention will be explained in more detail with reference to Examples. The invention is not limited to the examples shown below.

(Production Example 1: Preparation of photocurable composition)
100 parts by weight of n-butyl acrylate (BA), 5 parts by weight of acrylic acid (AA), and 0.1 part by weight of 2-hydroxyethyl acrylate (2HEA), and Omnirad 184 and Omnirad 651 (both manufactured by IGM Resins) as photopolymerization initiators. 0.05 parts by weight of each were put into a Lof flask and irradiated with ultraviolet rays under a nitrogen atmosphere to obtain a partially photopolymerized monomer syrup. The ultraviolet irradiation was carried out until the viscosity of the solution in the flask (measurement conditions: BH viscometer No. 5 rotor, 10 rpm, measurement temperature 30° C.) reached approximately 20 Pa·s. Next, 0.1 part by weight of 1,9-nonanediol diacrylate (NDDA) as a crosslinking agent was uniformly mixed with 100 parts by weight of the monomer syrup to obtain a photocurable composition.

(Production Example 2: Production of release liner A)
100 parts by weight of addition reaction-curing silicone (LTC761 containing hexenyl group-containing polyorganosiloxane, 30% by weight toluene solution, manufactured by Toray Dow Corning), release control agent (BY24-850 containing unreacted silicone resin, Toray Dow Corning) (manufactured by Corning), 2 parts by weight of a curing catalyst (SRX212 containing platinum catalyst, manufactured by Dow Corning Toray), and a mixed solvent of toluene/hexane (volume ratio 1:1) as a diluting solvent. Silicone mold release agent composition A was obtained. The concentration of silicone solids in mold release agent composition A was 1.0% by weight. Next, mold release agent composition A was applied to one side of the liner base material (Lumirror 38R75, a polyester film, thickness 38 μm) using a wire bar, heated at 130°C for 1 minute, and a mold release layer (60 nm thickness) was applied. ) was prepared on one side.

(Production Example 3: Production of release liner B)
A release liner B having a release layer (thickness 120 nm) on one side was produced in the same manner as Production Example 2 except that the thickness of the release agent composition A applied to the liner base material was changed.

(Production Example 4: Production of release liner C)
33.3 parts by weight of addition reaction-curing silicone (KS-847T containing vinyl group-containing polyorganosiloxane, 30% by weight toluene solution, manufactured by Shin-Etsu Chemical) and curing catalyst (CAT-PL-50T containing platinum catalyst, manufactured by Shin-Etsu Chemical) Silicone mold release agent composition C was obtained by mixing 1 part by weight of the silicone-based mold release agent composition C) and a toluene/hexane mixed solvent (volume ratio 1:1) as a diluting solvent. The concentration of silicone solids in mold release agent composition C was 1.0% by weight. Next, mold release agent composition C was applied to one side of the liner base material (Lumirror 38R75, which is a polyester film, thickness 38 μm) using a wire bar, and heated at 130°C for 1 minute to form a mold release layer (thickness 100 nm). ) was prepared on one side.

[Formation of adhesive sheet]
(Sample 1)
The photocurable composition of Production Example 1 is applied to one side of the first base sheet (Lumirror 38R75, a polyester film without a release layer, thickness 38 μm) using an applicator to form a first coating layer. did. Next, release liner A of Production Example 2 was placed on the first coating layer to obtain a first laminate. Release liner A was placed so that the release layer was in contact with the first coating layer. Next, ultraviolet light (black light source) is irradiated from the release liner A side of the first laminate at an illuminance of 2.4 mW/cm ² and an integrated light amount of 2880 mJ/cm ² to expose the first coating layer to light. By curing, a laminate 17 composed of the first base sheet, the first adhesive sheet (thickness: 20 μm), and the release liner A was formed.

A test piece with a length of 220 mm and a width of 50 mm (the length direction is the direction in which the photocurable composition was applied) was cut out from the formed laminate 17. The test piece was subjected to a 180° peel test in which only the release liner A was peeled off in the length direction using a tensile tester to evaluate the peeling force of the release liner A against the first pressure-sensitive adhesive sheet. The conditions for the peel test were as described above. The peeling force was 0.07N/50mm.

After removing a portion of the laminate 17 in the longitudinal direction so as not to include the sampled portion of the test piece, the release liner A was peeled off. The release liner A was peeled off by peeling the release liner A 180° from the longitudinal end with the first base sheet side of the laminate 17 fixed with double-sided adhesive tape. Next, the peeled release liner A was used as a second base sheet to form a second laminate. The second laminate was prepared by applying the photocurable composition of Production Example 1 to the surface of the second base sheet on the release layer side using an applicator to form a second coating layer, and then applying the second coating layer. Release liner A (unused product) of Production Example 2 was placed on top of the layer. Next, ultraviolet light (black light source) is irradiated from the release liner A side of the second laminate at an illuminance of 2.4 mW/cm ² and an integrated light amount of 2880 mJ/cm ² to expose the second coating layer to light. By curing, a laminate 27 composed of the second base sheet, the second adhesive sheet (thickness: 20 μm), and release liner A was formed. Note that the second adhesive sheet formed was the same as the first adhesive sheet.

A test piece with a length of 220 mm and a width of 50 mm (the length direction is the direction in which the photocurable composition was applied) was cut from the formed laminate 27. The test piece was subjected to a 180° peel test in which only the release liner A was peeled off in the length direction, and then a 180° peel test in which only the second base sheet was peeled off in the length direction using a tensile tester. The peel force of the release liner A and the second base sheet with respect to the second pressure-sensitive adhesive sheet was evaluated. The conditions for the peel test were as described above. The release force of release liner A was 0.07 N/50 mm, and the release force of the second base sheet was 0.11 N/50 mm. Note that it was possible to peel only the release liner A from the test piece without peeling off the second base sheet.

(Sample 2)
A first adhesive sheet and a second adhesive sheet were formed in the same manner as Sample 1 except that release liner B of Production Example 3 was used instead of release liner A. The peel force of release liner B against the first pressure-sensitive adhesive sheet was 0.04 N/50 mm. The peel forces of the release liner B and the second base sheet (recycled release liner B) against the second adhesive sheet were 0.04 N/50 mm and 0.51 N/50 mm, respectively. Note that it was possible to peel only the release liner B from the test piece without peeling off the second base sheet.

(Sample 3)
A first adhesive sheet and a second adhesive sheet were formed in the same manner as Sample 1 except that release liner C of Production Example 4 was used instead of release liner A. The peel force of release liner C against the first adhesive sheet was 0.22 N/50 mm. The peel forces of the release liner C and the second base sheet (recycled release liner C) against the second adhesive sheet were 0.22 N/50 mm and 7.57 N/50 mm, respectively. Note that it was possible to peel only the release liner C from the test piece without peeling off the second base sheet.

(Sample 4)
The second adhesive sheet was prepared in the same manner as Sample 1 except that the release liner A (unused product) of Production Example 2 was also used for the second base sheet instead of the release liner A that was peeled off from the first adhesive sheet. An adhesive sheet was formed. An attempt was made to peel off only one release liner A from a test piece taken from a laminate containing the second adhesive sheet, but both release liners A peeled off and the second adhesive sheet was exposed alone. became.

(Sample 5)
A second adhesive sheet was prepared in the same manner as Sample 1 except that the release liner A peeled from the first adhesive sheet was also used for the second release liner instead of release liner A (unused product) of Production Example 2. was formed. An attempt was made to peel off only one release liner A from a test piece taken from a laminate containing the second adhesive sheet, but both release liners A peeled off and the second adhesive sheet was exposed alone. became.

(Sample 6)
The second adhesive sheet was prepared in the same manner as Sample 2 except that the release liner B (unused product) of Production Example 3 was also used for the second base sheet instead of the release liner B that was peeled off from the first adhesive sheet. An adhesive sheet was formed. An attempt was made to peel off only one release liner B from a test piece taken from a laminate containing the second adhesive sheet, but both release liners B peeled off and the second adhesive sheet was exposed alone. became.

The pressure-sensitive adhesive sheet obtained by the production method of the present invention can be used, for example, in optical laminates and image display devices.

1A First adhesive sheet 1B Second adhesive sheet 2, 2A, 2B Optical film 10 First laminate 11A First base sheet 11B Second base sheet 12A First coating layer 12B Second coating Layer 13A First release liner 13B Second release liner 131 Liner base material 132 Release layers 14A, 14B Light 18 Exposed surface 20 Second laminate 41, 42 Optical film with adhesive sheet

Claims (10)

A first laminate including a first base sheet, a first coating layer containing a first photocurable composition, and a first release liner in this order is irradiated with light to perform the first coating. forming a first adhesive sheet from the layers;
A second coating comprising the second base sheet and a second photocurable composition formed using the first release liner peeled from the first adhesive sheet as a second base sheet. forming a second adhesive sheet from the second coating layer by irradiating a second laminate including a layer and a second release liner in this order with light,
The second base sheet has a greater release force with respect to the second adhesive sheet than the second release liner.
Method for manufacturing adhesive sheets. The method for producing a pressure-sensitive adhesive sheet according to claim 1, wherein the first laminate is irradiated with the light from the first release liner side. The second base sheet and the second release liner both include a release layer on the surface on the second coating layer side,
The release layer included in the second base sheet and the release layer included in the second release liner are layers formed from release agent compositions containing the same release agent as a main component. The method for producing a pressure-sensitive adhesive sheet according to claim 1. The adhesive sheet according to claim 1, wherein the peeling force between the second base sheet and the second adhesive sheet is greater than the peeling force between the first release liner and the first adhesive sheet. manufacturing method. The method for producing a pressure-sensitive adhesive sheet according to claim 1, wherein the first photocurable composition and the second photocurable composition are the same composition. The first photocurable composition and the second photocurable composition contain a monomer group containing a (meth)acrylic monomer and/or a partial polymer of the monomer group, The method for producing a pressure-sensitive adhesive sheet according to claim 1. The method for producing a pressure-sensitive adhesive sheet according to claim 6, wherein the (meth)acrylic monomer includes a carboxyl group-containing monomer. A first laminate including a first base sheet, a first coating layer containing a first photocurable composition, and a first release liner in this order is irradiated with light to perform the first coating. forming a first adhesive sheet from the layers;
A second coating layer containing the second base sheet and a second photocurable composition, using the first release liner peeled from the first adhesive sheet as a second base sheet; and forming a second laminate including a second release liner in this order;
A method for manufacturing a laminate, including: Production of an optical film with a pressure-sensitive adhesive sheet, the method comprising forming an optical film with a pressure-sensitive adhesive sheet by disposing an optical film on the exposed surface of a pressure-sensitive adhesive sheet formed by the production method according to any one of claims 1 to 7. Method. The method for producing an optical film with a pressure-sensitive adhesive sheet according to claim 9, wherein the optical film includes at least one film selected from the group consisting of a polarizing film and a retardation film.

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