Method for producing pressure-sensitive adhesive sheet and method for producing optical film with pressure-sensitive adhesive sheet

Abstract

To provide a technique suitable for manufacturing a pressure sensitive adhesive sheet with a low environmental load.SOLUTION: A manufacturing method of a pressure sensitive adhesive sheet includes: a step A of using a release liner and irradiating with light a laminate including a base material sheet, a coating layer containing a photo-curable composition and the release liner in this order to form a pressure sensitive adhesive sheet from the coating layer; and a step B of removing the release liner from the pressure sensitive adhesive sheet. In the manufacturing method, using the release liner removed at the step B, the step A and the step B are repeatedly carried out. As the release liner, a sheet is used in which a peel force PS3 from the pressure sensitive adhesive sheet measured after having removed from the pressure sensitive adhesive sheet three times from an unused state is less than 1.0 N / 50 mm.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a method for producing a pressure-sensitive adhesive sheet, and a method for producing an optical film with a pressure-sensitive adhesive sheet. [Background technology]

[0002] Various image display devices, such as liquid crystal display devices and electroluminescence (EL) display devices, generally include an optical laminate including an optical film such as a polarizing film and an adhesive sheet. An adhesive sheet is usually used for bonding between the optical films included in the optical laminate and bonding between the optical laminate and an image display panel. A typical adhesive sheet is a sheet obtained by curing a monomer group including an acrylic monomer, a silicone monomer, etc., by polymerization and crosslinking. Patent Document 1 discloses a method of forming an adhesive sheet from a coating layer by irradiating light to a laminate including a base sheet, a coating layer including a photocurable composition, and a release liner in this order. In this method, both main surfaces of the coating layer are covered by the base sheet and the release liner, so that the inhibition of the photocuring reaction caused by oxygen can be suppressed. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2016-155981 A Summary of the Invention [Problem to be solved by the invention]

[0004] Formation of an adhesive sheet by curing usually requires energy such as heat or light. According to a method that utilizes light (photocuring method), the amount of energy required to form an adhesive sheet can be reduced compared to, for example, a method (thermal curing method) in which a coating layer containing an adhesive composition and a solvent is thermally cured in an oven. However, from the viewpoint of reducing the environmental load during the production of an adhesive sheet, it is not sufficient to only focus on the amount of energy required to cure the coating layer.

[0005] An object of the present invention is to provide a technique suitable for producing a pressure-sensitive adhesive sheet with low environmental impact. [Means for solving the problem]

[0006] The present invention relates to A step A of irradiating a laminate including a base sheet, a coating layer including a photocurable composition, and the release liner in this order with light using a release liner to form a pressure-sensitive adhesive sheet from the coating layer; and step B of peeling the release liner from the pressure-sensitive adhesive sheet, The steps A and B are repeatedly performed using the release liner peeled off in the step B, The release liner was peeled from the adhesive sheet three times, counting from an unused state, and then the peel strength PS between the release liner and the adhesive sheet was measured. 3 Use a sheet with a strength of less than 1.0N / 50mm. A method for producing a pressure-sensitive adhesive sheet, to provide.

[0007] In another aspect, the present invention provides a method for producing a composition comprising: A method for producing an optical film with a pressure-sensitive adhesive sheet, comprising: arranging an optical film on an exposed surface of the pressure-sensitive adhesive sheet formed by the pressure-sensitive adhesive sheet producing method of the present invention to form an optical film with a pressure-sensitive adhesive sheet; to provide. Effect of the Invention

[0008] According to the present invention, a technique suitable for producing a pressure-sensitive adhesive sheet with low environmental impact can be provided. [Brief description of the drawings]

[0009] [Figure 1] 1A to 1C are schematic diagrams illustrating an example of a method for producing a pressure-sensitive adhesive sheet of the present invention. [Diagram 2] FIG. 1 is a cross-sectional view that illustrates a schematic example of a release liner that can be used in the method for producing a pressure-sensitive adhesive sheet of the present invention. [Diagram 3]1A to 1C are schematic diagrams illustrating an example of a method for producing a pressure-sensitive adhesive sheet of the present invention. [Figure 4] 1A to 1C are schematic diagrams illustrating an example of a method for producing a pressure-sensitive adhesive sheet of the present invention. [Diagram 5] FIG. 2 is a schematic diagram for explaining an example of a method for producing an optical film with a pressure-sensitive adhesive sheet of the present invention. [Figure 6] FIG. 2 is a schematic diagram for explaining an example of a method for producing an optical film with a pressure-sensitive adhesive sheet of the present invention. [Figure 7] FIG. 2 is a schematic diagram for explaining an example of a method for producing an optical film with a pressure-sensitive adhesive sheet of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] A method for producing a pressure-sensitive adhesive sheet according to a first aspect of the present invention includes the steps of: A step A of irradiating a laminate including a base sheet, a coating layer including a photocurable composition, and the release liner in this order with light using a release liner to form a pressure-sensitive adhesive sheet from the coating layer; and step B of peeling the release liner from the pressure-sensitive adhesive sheet, The steps A and B are repeatedly performed using the release liner peeled off in the step B, The release liner was peeled from the adhesive sheet three times, counting from an unused state, and then the peel strength PS between the release liner and the adhesive sheet was measured. 3 Use a sheet with a strength of less than 1.0N / 50mm.

[0011] In a second aspect of the present invention, for example, in the method for producing a pressure-sensitive adhesive sheet according to the first aspect, The release liner is subjected to a peel strength (PS) measurement with respect to the adhesive sheet when it is unused. 0 is 0.01N / 50mm or more.

[0012] In a third aspect of the present invention, for example, in the method for producing a pressure-sensitive adhesive sheet according to the first or second aspect, The release liner is subjected to a peel strength (PS) measurement with respect to the adhesive sheet when it is unused.0 The peel force P.S. 3 PS 3 / PS 0 is less than or equal to 10.

[0013] In a fourth aspect of the present invention, for example, in a method for producing a pressure-sensitive adhesive sheet according to any one of the first to third aspects, The release liner is subjected to a peel strength (PS) measurement with respect to the adhesive sheet when it is unused. 0 The peel strength PS between the adhesive sheet and the adhesive sheet was measured after peeling it once from the adhesive sheet, counting from the unused state. 1 PS 1 / PS 0 is less than or equal to 10.

[0014] In a fifth aspect of the present invention, for example, in a method for producing a pressure-sensitive adhesive sheet according to any one of the first to fourth aspects, the release liner has a release layer on the surface of the coating layer; The release layer has a thickness of 110 nm or less.

[0015] In a sixth aspect of the present invention, for example, in a method for producing a pressure-sensitive adhesive sheet according to any one of the first to fifth aspects, The peel strength between the release liner and the pressure-sensitive adhesive sheet is smaller than the peel strength between the base sheet and the pressure-sensitive adhesive sheet.

[0016] In a seventh aspect of the present invention, for example, in a method for producing a pressure-sensitive adhesive sheet according to any one of the first to sixth aspects, The photocurable composition contains a monomer group including a (meth)acrylic monomer and / or a partial polymer of the monomer group.

[0017] In an eighth aspect of the present invention, for example, in the method for producing a pressure-sensitive adhesive sheet according to the seventh aspect, The (meth)acrylic monomer includes a carboxyl group-containing monomer.

[0018] A method for producing an optical film with a pressure-sensitive adhesive sheet according to a ninth aspect of the present invention includes the steps of: The method includes forming an optical film with a pressure-sensitive adhesive sheet by disposing an optical film on an exposed surface of the pressure-sensitive adhesive sheet formed by the method for producing a pressure-sensitive adhesive sheet according to any one of the first to eighth aspects.

[0019] In a 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.

[0020] The present invention will be described in detail below, but the present invention is not limited to the following embodiments and can be modified in any manner without departing from the gist of the present invention.

[0021] The inventors came up with the idea of ​​further reducing the environmental impact of the manufacturing process of adhesive sheets by reusing release liners that were previously discarded immediately after peeling, and further research was conducted based on this idea, leading to the completion of the present invention. The release force of a release liner after it has been peeled from an adhesive sheet is greater than when it is unused. Meanwhile, the inventors' research has shown that the degree of increase in release force tends to decrease with increasing number of peelings. The release force PS after it has been peeled from an adhesive sheet three times, counting from an unused state, is 3 is useful as an index reflecting the increase in peel strength. 3 Release liners with a strength of less than 1.0 N / 50 mm are suitable for repeated use. The more they are used, the less release liners are discarded, and the less environmental impact there is.

[0022] [Method of manufacturing adhesive sheet] An example of the method for producing a pressure-sensitive adhesive sheet of the present invention will be described with reference to FIG. 1. In this example, a first laminate 10 including a base sheet 11, a coating layer 12 containing a photocurable composition, and a release liner 13 in this order is irradiated with light 14 to form a pressure-sensitive adhesive sheet 1 from the coating layer 12 (step A). ​​The light 14 penetrates the release liner 13 to reach the coating layer 12, and cures the coating layer 12. However, the irradiation with light 14 may be performed from the side of the base sheet 11, or from both the side of the release liner 13 and the base sheet 11. In step A, the pressure-sensitive adhesive sheet 1 is formed using the release liner 13. The formed pressure-sensitive adhesive sheet 1 is sandwiched between the base sheet 11 and the release liner 13 to form a part of the second laminate 17 until the release liner 13 is peeled off. After step A, the release liner 13 is peeled off from the pressure-sensitive adhesive sheet 1 (step B). 1, steps A and B are repeatedly performed using the release liner 13 peeled off in step B. Step A using the peeled release liner 13 is performed by forming a first laminate 10 including, in this order, a base sheet 11, a coating layer 12, and the peeled release liner 13, and irradiating the formed first laminate 10 with light 14.

[0023] In the method of FIG. 1, the release liner 13 is peeled from the adhesive sheet 1 three times, counting from an unused state, and then the peel strength PS 3 A sheet having a peel strength of less than 1.0 N / 50 mm is used. As step A is carried out, the peel strength of the release liner 13 with respect to the adhesive sheet 1 usually increases. The increase in peel strength is presumably due to an increase in the amount of functional groups and radicals present on the surface of the release liner 13 facing the coating layer 12 due to irradiation with light 14. This increase may be due to the fact that chemical bonds are formed between the release liner 13 and the adhesive sheet 1 by irradiation with light 14, and that part of these bonds or radicals formed by decomposition of the bonds remain on the surface even after the adhesive sheet 1 is peeled off.

[0024] <Process A> (Release liner) Release force of release liner 13 PS 3may be 0.9N / 50mm or less, 0.8N / 50mm or less, 0.7N / 50mm or less, 0.6N / 50mm or less, 0.5N / 50mm or less, 0.4N / 50mm or less, 0.3N / 50mm or less, 0.2N / 50mm or less, or even 0.15N / 50mm or less. 3 The lower limit is, for example, 0.01 N / 50 mm or more, and may be 0.03 N / 50 mm or more, 0.05 N / 50 mm or more, 0.08 N / 50 mm or more, or even 0.1 N / 50 mm or more.

[0025] The release liner 13 has a peel strength (PS) between itself and the adhesive sheet 1 when it is unused. 0 The peel strength PS may be 0.01 N / 50 mm or more, 0.02 N / 50 mm or more, or even 0.03 N / 50 mm or more. 0 The upper limit is, for example, 0.2 N / 50 mm or less, and may be 0.17 N / 50 mm or less, 0.15 N / 50 mm or less, 0.12 N / 50 mm or less, or even 0.1 N / 50 mm or less.

[0026] The release liner 13 has a peel strength (PS) between itself and the adhesive sheet 1 when it is unused. 0 Peel force against PS 3 PS 3 / PS 0 The ratio PS may be 10 or less, 7 or less, 5 or less, 4 or less, 3 or less, 2 or less, or even 1.8 or less. 3 / PS 0 The lower limit is, for example, 1.1 or more, or even 1.2 or more.

[0027] The release liner 13 has a peel strength (PS) between itself and the adhesive sheet 1 when it is unused. 0 The peel strength PS between the adhesive sheet 1 and the adhesive sheet 1 was measured after peeling it once from the unused state. 1 PS 1 / PS 0 may be 10 or less, 7 or less, 5 or less, 4 or less, 3 or less, 2 or less, 1.8 or less, or even 1.7 or less. 1 / PS 0The lower limit is, for example, 1.05 or more, or even 1.1 or more.

[0028] Peel strength PS after peeling n times from adhesive sheet 1, counting from an unused state n (n is an integer equal to or greater than 0, which corresponds to the number of peels; when n=0, the peel strength in the unused state is PS 0 ) can be evaluated by performing step A and step B n times using the release liner to be evaluated, and then performing step A (n+1) times to cut the second laminate 17 formed to a width of 50 mm to prepare a test piece, and performing a 180° peel test in which only the release liner 13 is peeled off from the prepared test piece. The peel test is performed about 0.5 to 1 hour after the formation of the pressure-sensitive adhesive sheet 1. From the formation of the pressure-sensitive adhesive sheet 1 to the performance of the peel test, the second laminate 17 and the test piece are placed in an air atmosphere at 23°C ± 5°C. A tensile tester can be used for the peel test. More specifically, the entire surface of the test piece on the side of the base sheet 11 is fixed to a fixing plate (e.g., a SUS plate) with double-sided adhesive tape, and then one end in the length direction of the fixing plate is fixed to the upper chuck of the tensile tester, and the end of the release liner 13 on the upper chuck side is peeled off and folded back 180°, and fixed to the lower chuck of the tensile tester. The fixing plate may have sufficient mechanical strength to perform the peel test stably. The double-sided adhesive tape may have sufficient adhesive strength to prevent the base sheet 11 from peeling off from the fixing plate during the peel test. The peel test is performed at a peel speed of 300 mm / min and at a test temperature of 23°C ± 5°C. If the width of the second laminate 17 is less than 50 mm, the measured value in the original width may be converted to a value per 50 mm width. If the formation direction of the coating layer 12 can be determined, the TD perpendicular to the MD direction can be determined as the width direction of the test piece. If the base sheet 11 and the release liner 13 are long, the width direction of the test piece can be determined as the width direction of the test piece.

[0029] Peeling force PS 0 , P.S. n and PS by repeated peeling. nThe degree of increase can vary depending on, for example, the composition of the photocurable composition, the composition, formation conditions and thickness of the adhesive sheet 1 to be formed, the material, thickness and condition of the release surface of the release liner 13, and the composition, formation conditions and thickness of a release layer that the release liner 13 may have.

[0030] An example of the substrate of the release liner 13 (hereinafter referred to as the "liner substrate") is a resin film. Examples of resins that may be included in the liner substrate include polyesters such as polyethylene terephthalate and polyethylene naphthalate, acetate resins, polyethersulfone, polycarbonate, polyamide, polyimide, polyolefin, (meth)acrylic resins, polyvinyl chloride, polyvinylidene chloride, polystyrene, polyvinyl alcohol, polyarylate, and polyphenylene sulfide. The resin is preferably a polyester such as polyethylene terephthalate.

[0031] It is preferable that the release liner 13 has excellent transmittance for the light 14 irradiated in step A.

[0032] The thickness of the release liner 13 is, for example, 10 to 200 μm, and may be 25 to 150 μm.

[0033] The release liner 13 may include a layer other than the liner substrate. The release liner 13 may include a release layer. The release liner 13 in Fig. 2 includes a liner substrate 131 and a release layer 132 formed on one surface of the liner substrate 131. The release liner 13 in Fig. 2 can be used such that the release layer 132 is on the coating layer 12 side.

[0034] The release layer 132 is typically a cured layer of a release agent composition containing a release agent. As the release agent, various types of release agents can be used, such as silicone-based release agents, fluorine-based release agents, long-chain alkyl-based release agents, fatty acid amide-based release agents, and silica powder. The release liner 13 may be provided with a cured layer of a release agent composition containing a silicone-based release agent as a main component (hereinafter, "silicone release layer"). The silicone release layer is particularly suitable for achieving both adhesion and releasability to the acrylic adhesive sheet 1. In this specification, the main component means the component with the largest content.

[0035] The silicone-based release agent is, for example, various curable silicone materials such as addition reaction type, condensation reaction type, ultraviolet curable type, electron beam curable type, and solventless type, and an addition reaction curable silicone material is preferred. An addition reaction curable silicone material is particularly suitable for forming a release layer that has both adhesion and releasability to the acrylic adhesive sheet 1. 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.

[0036] An example of the addition reaction curing silicone material is a polyorganosiloxane having a vinyl group or an alkenyl group in the molecule. The addition reaction curing silicone material may not have a hydrosilyl group. Examples of the alkenyl group are 3-butenyl, 4-pentenyl, 5-hexenyl, 6-heptenyl, 7-octenyl, 8-nonenyl, 9-decenyl, 10-undecenyl, and 11-dodecenyl. Examples of the polyorganosiloxane are polyalkylalkylsiloxanes such as polydimethylsiloxane, polydiethylsiloxane, and polymethylethylsiloxane, polyalkylarylsiloxane, and copolymers of multiple types of Si atom-containing monomers such as poly(dimethylsiloxane-diethylsiloxane). The polyorganosiloxane is preferably polydimethylsiloxane.

[0037] A release agent composition containing a silicone-based release agent as a main component (hereinafter referred to as "silicone release agent composition") usually contains a crosslinking agent. An example of the crosslinking agent is polyorganosiloxane having a hydrosilyl group. The crosslinking agent may have two or more hydrosilyl groups in one molecule.

[0038] The silicone release agent composition may contain a curing catalyst. An example of the curing catalyst is a platinum catalyst. An example of the platinum catalyst is chloroplatinic acid, an olefin complex of platinum, or an olefin complex of chloroplatinic acid. The amount of the platinum catalyst used is, for example, 10 to 1000 ppm (weight basis, platinum equivalent) based on the total solid content of the composition.

[0039] The silicone release agent composition may contain additives. Examples of additives are release control agents and adhesion promoters. Examples of release control agents are unreactive silicone resins, and more specific examples are organosiloxanes such as octamethylcyclotetrasiloxane, and MQ resins. The amount of the release control agent and adhesion promoter used is, for example, 1 to 30% by weight in total based on the total solid content of the composition. Further examples of additives are fillers, antistatic agents, antioxidants, ultraviolet absorbers, plasticizers, and colorants. The amount of the further additives used is, for example, 10% by weight or less in total based on the total solid content of the composition.

[0040] The silicone release agent composition may contain an organic solvent. Examples of the organic solvent 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; and alcohol solvents such as methanol, ethanol, and butanol. Two or more organic solvents may be contained. The amount of the organic solvent used is preferably 80 to 99.9% by weight of the silicone release agent composition.

[0041] 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 substrate 131. For coating the release agent composition, various coating methods such as 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 can be applied. For heating and drying, for example, hot air drying can be applied. The heating temperature and time vary depending on the heat resistance of the liner substrate, but are usually about 80 to 150°C and 10 seconds to 10 minutes. If necessary, irradiation with active energy rays such as ultraviolet rays may be used in combination.

[0042] 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 thickness of the release layer 132 may be 110 nm or less, in other words, the release liner 13 may have the release layer 132 on the surface on the side of the coating layer 12, and the thickness of the release layer 132 may be 110 nm or less.

[0043] The release liner 13 may be in the form of a sheet or a continuous piece.

[0044] (Base sheet) An example of the base sheet 11 is a resin film. Examples of the resin contained in the base sheet 11 are the same as the examples of the resin that can be contained in the liner base material.

[0045] The base sheet 11 may have transparency to the light 14 irradiated in step A, or may have the same degree of transparency to the light 14 as the release liner 13 .

[0046] The thickness of the base sheet 11 is, for example, 10 to 200 μm, and may be 25 to 150 μm.

[0047] The base sheet 11 may have a release layer on the surface on the side of the coating layer 12. Examples of the release layer that the base sheet 11 may have and the manufacturing method thereof are the same as the examples of the release layer that the release liner 13 may have and the manufacturing method thereof. Both the release liner 13 and the base sheet 11 may have a release layer. In this case, both release layers may be formed from a release agent composition containing the same release agent as a main component. In addition, the thicknesses of both release layers may be different, and for example, the release layer provided on the base sheet 11 may be thicker.

[0048] For the base sheet 11, a sheet having a greater peeling strength from the adhesive sheet 1 than the release liner 13 can usually be selected.

[0049] The base sheet 11 may be in the form of a sheet or a continuous length.

[0050] (Photocurable composition) The photocurable composition is a composition that can form an adhesive sheet 1 from the coating layer 12 by irradiation with light 14. The photocurable composition contains, 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 photocurable composition, i.e., the (meth)acrylic monomer and its partial polymer, may be 50% by weight or more, 60% by weight or more, 70% by weight or more, or even 80% by weight or more. In this case, an acrylic adhesive sheet 1 containing a (meth)acrylic polymer and its crosslinked product as the main components can be formed. However, the photocurable composition is not limited to the above examples. In this specification, (meth)acrylic means acrylic and methacrylic. (Meth)acrylate means acrylate and methacrylate.

[0051] An example of the (meth)acrylic monomer is a (meth)acrylic acid alkyl ester having an alkyl group having 1 to 20 carbon atoms on 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 the (meth)acrylic acid alkyl ester 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, and the like. 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.

[0052] The content of the (meth)acrylic acid alkyl ester in the monomer group is, for example, 40% by weight or more, and may be 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, 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 into the weight of each monomer before polymerization.

[0053] The monomer group may contain a carboxyl group-containing monomer. The carboxyl group-containing monomer may be a (meth)acrylic monomer, in other words, the (meth)acrylic monomer may contain a carboxyl group-containing monomer. Examples of the carboxyl group-containing monomer 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 may be, 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, or even 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 may not contain a carboxyl group-containing monomer.

[0054] The rate of polymerization and curing of the carboxyl group-containing monomer by irradiation with light 14 is usually higher than that of (meth)acrylic acid alkyl esters that do not contain carboxyl groups. The higher rate means that the elastic modulus of the adhesive sheet 1 can be increased to improve the dimensional stability against deformation forces, but the peel force of the release liner with respect to the adhesive sheet 1 tends to be large. For this reason, the peel force PS 3 The use of a release liner 13 with reduced adhesion is particularly advantageous when the photocurable composition contains a carboxyl group-containing monomer.

[0055] The monomer group may contain a hydroxy group-containing monomer. The hydroxy group-containing monomer may be a (meth)acrylic monomer, in other words, the (meth)acrylic monomer may contain a hydroxy group-containing monomer. The hydroxy group-containing monomer may contribute to improving the cohesive strength of the adhesive sheet 1. Examples of the hydroxy group-containing monomer are 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, 6-hydroxyhexyl (meth)acrylate, 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 hydroxyl group-containing monomer in the monomer group is, for example, 5% by weight or less, and may be 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, or even 0.05% by weight or more. The monomer group may not contain a hydroxyl group-containing monomer.

[0056] In the photocurable composition, each of the above-mentioned monomers may be contained as a partial polymer. The partial polymer may be either a homopolymer or a copolymer. The partial polymer can contribute to the stable formation of the coating layer 12 by appropriately increasing the viscosity of the photocurable composition.

[0057] The photocurable composition usually contains a photopolymerization initiator. An example of the photopolymerization initiator is a photoradical generator that generates radicals when exposed to visible light and / or ultraviolet light having a wavelength shorter than 450 nm.

[0058] Examples of photopolymerization initiators include benzoin ethers such as benzoin methyl ether, benzoin isopropyl ether, and benzil dimethyl ketal; substituted benzoin ethers such as anisole methyl ether; substituted acetophenones such as 2,2-diethoxyacetophenone and 2,2-dimethoxy-2-phenylacetophenone; α-hydroxyalkylphenones such as 1-hydroxycyclohexyl-phenyl ketone; substituted alpha-ketol 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; and benzophenone compounds such as benzoylbenzoic acid, methyl benzoylbenzoate, 4-phenylbenzophenone, hydroxybenzophenone, acrylated benzophenone, 4-benzoyl-4'-methyldiphenyl sulfide, and 3,3',4,4'-tetra(t-butylperoxycarbonyl)benzophenone. Thioxanthone, 2-chlorothioxanthone, 2-methylthioxanthone, isopropylthioxanthone, 2,4-diisopropylthioxanthone, 2,4-diethylthioxanthone and other thioxanthone compounds; 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-based compounds;Oxime ester compounds such as 1,2-octanedione, 1-[4-(phenylthio)-, 2-(O-benzoyloxime)], O-(acetyl)-N-(1-phenyl-2-oxo-2-(4'-methoxy-naphthyl)ethylidene)hydroxylamine; phosphine compounds such as bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide, 2,4,6-trimethylbenzoyldiphenylphosphine oxide; quinone compounds such as 9,10-phenanthrenequinone, camphorquinone, ethylanthraquinone; borate compounds; carbazole compounds; imidazole compounds; and titanocene compounds. The photocurable composition may contain one or more photopolymerization initiators.

[0059] The amount of the photopolymerization initiator in the photocurable composition is, for example, 0.02 to 10 parts by weight, and may be 0.05 to 5 parts by weight, based on 100 parts by weight in total of the monomer group and its partial polymer.

[0060] The photocurable composition may contain a crosslinking agent. An example of the 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. An example of the polyfunctional monomer is a monomer having two or more C=C bonds in one molecule, and a monomer having one or more C=C bonds and one or more polymerizable functional groups such as epoxy groups, aziridine groups, oxazoline groups, hydrazine groups, methylol groups, etc. in one molecule. The polyfunctional monomer is preferably a monomer having two or more C=C bonds in one molecule.

[0061] Examples of crosslinking agents include (poly)ethylene glycol di(meth)acrylate, (poly)propylene glycol di(meth)acrylate, neopentyl glycol di(meth)acrylate, pentaerythritol di(meth)acrylate, pentaerythritol tri(meth)acrylate, dipentaerythritol hexa(meth)acrylate, 1,2-ethylene glycol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, 1,9-nonanediol diacrylate (NDD A), polyfunctional acrylates such as 1,12-dodecanediol di(meth)acrylate, trimethylolpropane tri(meth)acrylate, and tetramethylolmethane tri(meth)acrylate (such as ester compounds of polyhydric alcohols and (meth)acrylic acid); 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, and more preferably trimethylolpropane tri(meth)acrylate, hexanediol di(meth)acrylate, and dipentaerythritol hexa(meth)acrylate.

[0062] The amount of the crosslinking agent to be blended varies depending on the molecular weight, the number of functional groups, etc., but may be, for example, 5 parts by weight or less, 3 parts by weight or less, 2 parts by weight or less, 1 part by weight or less, or even 0.5 parts by weight or less per 100 parts by weight of the total of the monomer group and its partial polymer. The lower limit of the blending amount is, for example, 0.01 parts by weight or more, and may be 0.05 parts by weight or more.

[0063] The photocurable composition may contain additives other than those described above. Examples of the additives include a chain transfer agent, a silane coupling agent, a viscosity modifier, a tackifier, a plasticizer, a softener, an antiaging agent, a filler, a colorant, an antioxidant, a surfactant, an antistatic agent, and an ultraviolet absorbing agent.

[0064] The content of the solvent in the photocurable composition is, for example, 5% by weight or less, and may be 4% by weight or less, 3% by weight or less, 2% by weight or less, 1% by weight or less, or even 0.5% by weight or less. The photocurable composition may be substantially free of a solvent. The phrase "substantially free of a solvent" means that the solvent derived from additives or the like is allowed to be present at a content of, for example, 0.1% by weight or less, preferably 0.05% by weight or less, and more preferably 0.01% by weight or less.

[0065] The viscosity of the photocurable composition is preferably 5 to 100 poise. A photocurable composition having a viscosity in the above range is particularly suitable for forming the coating layer 12.

[0066] (First laminate and its formation) The first laminate 10 may include an additional layer other than the base sheet 11, the coating layer 12, and the release liner 13. The additional layer may be disposed on the side of the base sheet 11 and / or the release liner 13 opposite to the side of the coating layer 12. The coating layer 12 is preferably in contact with the base sheet 11 and the release liner 13.

[0067] The first laminate 10 can be formed, for example, by forming a coating layer 12 on a base sheet 11 (or a release liner 13) and then arranging a release liner 13 (or base sheet 11) on the formed coating layer 12. Alternatively, the first laminate 10 may be formed by applying a photocurable composition by pouring it into the space between the base sheet 11 and the release liner 13 that are held at a predetermined distance so that their main surfaces face each other. The peeled release liner 13 may be used such that the surface that was on the side of the coating layer 12 in step A immediately before peeling, for example the surface on the release layer 132 side, becomes the side of the coating layer 12 again.

[0068] The coating layer 12 can be formed by various coating methods such as roll coating, kiss roll coating, gravure coating, reverse coating, roll brush, spray coating, dip roll coating, bar coating, knife coating, air knife coating, curtain coating, lip coating, and die coating.

[0069] The thickness of coating layer 12 can be adjusted depending on the desired thickness of adhesive sheet 1, and may be, for example, 5 to 100 μm, 5 to 50 μm, 5 to 25 μm, or even 5 to 20 μm.

[0070] The first laminate 10 may include a long base sheet 11, a long coating layer 12, and a long release liner 13, in other words, may be long. The long first laminate 10 can be obtained, for example, by forming the coating layer 12 between the base sheet 11 and the release liner 13 while conveying them, the base sheet 11 and the release liner 13 being unwound from a roll.

[0071] (Light irradiation) The light 14 irradiated to the first laminate 10 is, for example, visible light or ultraviolet light having a wavelength shorter than 450 nm. The light 14 may contain light having a wavelength in the same region as the absorption wavelength of the photopolymerization initiator contained in the photocurable composition. The light 14 may be irradiated with light having a short wavelength of 300 nm or less cut by a filter or the like, and cutting short wavelength light is suitable for suppressing deterioration of the release liner 13 caused by the light 14. The light source of the light 14 is, for example, a light irradiation device equipped with an ultraviolet irradiation lamp. Examples of the ultraviolet irradiation lamp are ultraviolet LED, low pressure mercury lamp, medium pressure mercury lamp, high pressure mercury lamp, ultra-high pressure mercury lamp, metal halide lamp, xenon lamp, microwave excited mercury lamp, black light lamp, chemical lamp, germicidal lamp, low pressure discharge mercury lamp, and excimer laser. Two or more ultraviolet irradiation lamps may be combined.

[0072] The illumination with light 14 may be continuous or intermittent.

[0073] The irradiation intensity of the light 14 is, for example, 1 to 20 mW / cm 2 The integrated amount of light 14 applied to the first laminate 10 is, for example, 100 to 5000 mJ / cm. 2 It is.

[0074] The polymerization rate of the monomer group in the pressure-sensitive adhesive sheet 1 is preferably 90% or more. The polymerization rate may be 95% or more, 98% or more, or even 99% or more.

[0075] The gel fraction of the pressure-sensitive adhesive sheet 1 is, for example, 50% or more, and may be 75% or more, 80% or more, or even 85% or more.

[0076] <Process B> In step B, the release liner 13 is peeled off from the cured second laminate 17. The second laminate 17 includes, in this order, a base sheet 11, an adhesive sheet 1, and a release liner 13. By the above peeling, a third laminate 15 including the release liner 13, and the base sheet 11 and the adhesive sheet 1 is obtained.

[0077] The peel strength between release liner 13 and adhesive sheet 1 may be smaller than the peel strength between base sheet 11 and adhesive sheet 1 .

[0078] The peeling force of the base sheet 11 from the pressure-sensitive adhesive sheet 1 is, for example, 0.1 to 10 N / 50 mm, and may be 1 to 8 N / 50 mm, 2 to 7 N / 50 mm, or even 3 to 5 N / 50 mm.

[0079] The number of times that the release liner 13 is peeled off and reused in the manufacture of the pressure-sensitive adhesive sheet 1 is not particularly limited, but may be, for example, 3 or more times, 5 or more times, or even 7 or more times. There is also no particular upper limit to the number of times, and for example, the peel strength PS n It may be continued to be used as long as the load does not exceed 3.0N / 50mm.

[0080] The peeled release liner 13 may be wound into a roll and then reused.

[0081] The thickness of the pressure-sensitive adhesive sheet 1 is, for example, 2 to 70 μm, and may be 2 to 50 μm, 5 to 40 μm, 10 to 30 μm, 10 to 25 μm, or even 10 to 20 μm.

[0082] The pressure-sensitive adhesive sheet 1 can be used, for example, in an optical laminate including an optical film. In other words, the pressure-sensitive adhesive sheet 1 may be for an optical laminate. The optical laminate may be an optical film with a pressure-sensitive adhesive sheet. However, the use of the pressure-sensitive adhesive sheet 1 is not limited to the above examples.

[0083] With reference to FIG. 3, another example of the method for producing a pressure-sensitive adhesive sheet of the present invention will be described. In this example, a coating layer 12 of a photocurable composition is formed on one side of a long base sheet 11 unwound from a roll 31 by a coating device 32. Next, a long release liner 13 unwound from a roll 33 is placed on the coating layer 12 to form a long first laminate 10. Next, light 14 is irradiated from a light irradiation device 34 to the first laminate 10 to form a long adhesive sheet 1. Next, the release liner 13 is peeled off from a second laminate 17 including the adhesive sheet 1 and wound up on a roll 35. The above steps are performed while the base sheet 11 and the release liner 13 are being transported. The wound release liner 13 is reused. The third laminate 15 formed by peeling off the release liner 13 can be used, for example, for an optical film with an adhesive sheet or for the production thereof. The method of FIG. 3 is particularly suitable for mass production of the adhesive sheet 1.

[0084] Another example of the method for producing 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 of Fig. 3, except that release liner 13 peeled off from second laminate 17 is reused in the production of pressure-sensitive adhesive sheet 1 without being wound up into roll 35. The method of Fig. 4 is particularly suitable for mass production of pressure-sensitive adhesive sheet 1.

[0085] [Release liner] According to a different aspect of the present invention, there is provided a release liner for use in the method for producing a pressure-sensitive adhesive sheet of the present invention. Examples of the release liner are the same as those mentioned above in the description of the method for producing a pressure-sensitive adhesive sheet.

[0086] [Method of manufacturing optical film with adhesive sheet] With reference to FIG. 5, an example of the manufacturing method of the optical film with adhesive sheet of the present invention will be described. In this example, an optical film 2 is arranged on the exposed surface 18 of the adhesive sheet 1 formed by peeling off the release liner 13 from the second laminate 17 including the base sheet 11, the adhesive sheet 1, and the release liner 13 in this order, to form an optical film 21 with an adhesive sheet. The optical film 21 with an adhesive sheet includes the base sheet 11, the adhesive sheet 1, and the optical film 2 in this order. The second laminate 17 can be formed by the above-mentioned step A. The release liner 13 may be peeled off as the above-mentioned step B. The optical film 21 with an adhesive sheet can be used as it is or after the base sheet 11 is peeled off, for example, as an optical laminate including the adhesive sheet 1 and the optical film 2 in an image display device or the like. The optical laminate may be attached to an object (for example, an image forming panel) via the adhesive sheet 1. However, the use of the optical film 21 with an adhesive sheet is not limited to the above-mentioned example. An additional member such as an optical film may be disposed on exposed surface 18 formed by peeling base sheet 11 from optical film 21 with adhesive sheet, and as one example, optical film 22 with adhesive sheet including optical film 2A, adhesive sheet 1, and optical film 2B in this order can be formed (see FIG. 6). Optical films 2A and 2B may be the same or different from each other.

[0087] The optical film 2 may be disposed directly or indirectly on the exposed surface 18. In other words, the optical film 2 may be disposed so as to be in contact with the exposed surface 18, or may be disposed with another layer sandwiched between the optical film 2 and the exposed surface 18.

[0088] With reference to Fig. 7, another example of the method for producing an optical film with a pressure-sensitive adhesive sheet of the present invention will be described. In this example, a long optical film 2 is arranged on the exposed surface 18 of the pressure-sensitive adhesive sheet 1 in the third laminate 15 formed by the method of Fig. 3 to form a long optical film with a pressure-sensitive adhesive sheet 21. The optical film 2 is unwound from a roll 36 and arranged on the exposed surface 18. As shown in Fig. 7, the formation of the pressure-sensitive adhesive sheet 1 and the formation of the optical film with a pressure-sensitive adhesive sheet 21 may be carried out continuously. The method of Fig. 7 is particularly suitable for mass production of the optical film with a pressure-sensitive adhesive sheet 21.

[0089] The optical film 2 is, for example, a film including 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 examples.

[0090] The polarizing film includes a polarizer. The polarizing film typically includes a polarizer and a protective film (transparent protective film). The protective film is disposed, for example, in contact with the main surface (surface having the widest area) of the polarizer. The polarizer may be disposed between two protective films. The protective film may be disposed on at least one surface of the polarizer.

[0091] The polarizer is not particularly limited, and examples thereof include hydrophilic polymer films such as polyvinyl alcohol films, partially formalized polyvinyl alcohol films, and partially saponified ethylene-vinyl acetate copolymer films, which are uniaxially stretched after adsorbing dichroic substances such as iodine and dichroic dyes; polyene-based oriented films such as dehydrated polyvinyl alcohol and dehydrochlorinated polyvinyl chloride; etc. Polarizers are typically made of polyvinyl alcohol films (polyvinyl alcohol films include partially saponified ethylene-vinyl acetate copolymer films) and dichroic substances such as iodine.

[0092] 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, a thickness of 20 μm or less) is suppressed in dimensional change, and can contribute to improving the durability of the optical laminate, particularly the durability at high temperatures.

[0093] As the material of the protective film, for example, a thermoplastic resin excellent in transparency, mechanical strength, thermal stability, moisture blocking property, isotropy, etc. is used. Specific examples of such thermoplastic resins include cellulose resins such as triacetyl cellulose, polyester resins, polyethersulfone resins, polysulfone resins, polycarbonate resins, polyamide resins, polyimide resins, polyolefin resins, (meth)acrylic resins, cyclic polyolefin resins (norbornene-based 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 a (meth)acrylic, urethane, acrylic urethane, epoxy, or silicone-based resin. When the polarizing film has two protective films, the materials of the two protective films may be the same or different from each other. For example, a protective film made of a thermoplastic resin may be bonded to one main surface of the polarizer via an adhesive, and a protective film made of a thermosetting resin or an ultraviolet-curing resin may be bonded to the other main surface of the polarizer. The protective film may contain one or more types of optional additives, such as ultraviolet absorbers, antioxidants, lubricants, plasticizers, release agents, color inhibitors, flame retardants, nucleating agents, antistatic agents, pigments, and colorants.

[0094] The thickness of the protective film can be appropriately determined, but is generally about 10 to 200 μm in terms of strength, workability such as handleability, thinness, and the like.

[0095] The polarizer and the protective film are usually adhered to each other via a water-based adhesive or the like. Examples of the water-based adhesive include an isocyanate-based adhesive, a polyvinyl alcohol-based adhesive, a gelatin-based adhesive, a vinyl-based latex, a water-based polyurethane, and a water-based polyester. Examples of adhesives other than the above-mentioned adhesives include an ultraviolet-curable adhesive and an electron beam-curable adhesive. The electron beam-curable polarizing plate adhesive exhibits suitable adhesion to various protective films. The adhesive may contain a metal compound filler.

[0096] In the polarizing film, a retardation film or the like can be formed on the polarizer instead of the protective film. Another protective film or a retardation film or the like can be further provided on the protective film.

[0097] The protective film may have a hard coat layer on the surface opposite to the surface bonded to the polarizer, and may also be subjected to treatments for the purposes of anti-reflection, anti-sticking, diffusion, anti-glare, etc.

[0098] The polarizing film may be a circular polarizing film.

[0099] The retardation film may be one obtained by stretching a polymer film or one obtained by aligning and fixing a liquid crystal material. The retardation film has birefringence, for example, in the in-plane and / or thickness direction.

[0100] Retardation films include anti-reflection retardation films (see JP 2012-133303 A,

[0221] ,

[0222] ,

[0228] ), viewing angle compensation retardation films (see JP 2012-133303 A,

[0225] ,

[0226] ), and tilted orientation retardation films for viewing angle compensation (see JP 2012-133303 A,

[0227] ).

[0101] The specific configuration of the retardation film, for example, the retardation value, arrangement angle, three-dimensional birefringence, whether it is a single layer or a multilayer, and the like, are not particularly limited, and any known retardation film can be used.

[0102] The thickness of the retardation film is preferably 20 μm or less, more preferably 10 μm or less, further preferably 1 to 9 μm, and particularly preferably 3 to 8 μm.

[0103] 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.

[0104] An image display device may be formed using the optical film with adhesive sheet formed by the above-mentioned manufacturing method. The image display device may be formed, for example, by bonding the optical film 21, 22 with adhesive sheet to an image display panel. The bonding may be performed by using an adhesive sheet 1. 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 examples. The image display device may be an electroluminescence (EL) display, a plasma display (PD), a field emission display (FED: Field Emission Display), or the like. The image display device may be used for home appliances, in-vehicle applications, public information displays (PID), and the like. EXAMPLES

[0105] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to the examples shown below.

[0106] (Production Example 1: Preparation of photocurable composition) 100 parts by weight of n-butyl acrylate (BA), 5 parts by weight of acrylic acid (AA), 0.1 parts by weight of 2-hydroxyethyl acrylate (2HEA), and 0.05 parts by weight each of Omnirad184 and Omnirad651 (both manufactured by IGM Resins) as photopolymerization initiators were placed in a four-bottom flask, and ultraviolet rays were irradiated under a nitrogen atmosphere to obtain a partially photopolymerized monomer syrup. The ultraviolet rays were irradiated 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 parts 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.

[0107] (Production Example 2: Preparation of Release Liner A) Addition reaction curing type silicone (LTC761 containing hexenyl group-containing polyorganosiloxane, 30 wt% toluene solution, manufactured by Dow Corning Toray) 100 parts by weight, release control agent (BY24-850 containing unreactive silicone resin, manufactured by Dow Corning Toray) 0.9 parts by weight, curing catalyst (SRX212 containing platinum catalyst, manufactured by Dow Corning Toray) 2 parts by weight, and toluene / hexane mixed solvent (volume ratio 1: 1) as a dilution solvent were mixed to obtain a silicone-based release agent composition A. The concentration of silicone solids in the release agent composition A was 1.0 wt%. Next, the release agent composition A was applied to one side of a liner substrate (Lumirror 38R75, a polyester film, thickness 38 μm) with a wire bar and heated at 130 ° C for 1 minute to prepare a release liner A having a release layer (thickness 60 nm) on one side.

[0108] (Production Example 3: Production of Release Liner B) A release liner B having a release layer (thickness 120 nm) on one side was prepared in the same manner as in Production Example 2, except that the thickness of the release agent composition A applied to the liner substrate was changed.

[0109] (Production Example 4: Preparation of Release Liner C) Addition reaction curing type silicone (KS-847T containing vinyl group-containing polyorganosiloxane, 30 wt% toluene solution, Shin-Etsu Chemical Co., Ltd.) 33.3 parts by weight, curing catalyst (CAT-PL-50T containing platinum catalyst, Shin-Etsu Chemical Co., Ltd.) 1 part by weight, and toluene / hexane mixed solvent (volume ratio 1: 1) as a dilution solvent were mixed to obtain a silicone-based release agent composition C. The concentration of silicone solids in the release agent composition C was 1.0 wt%. Next, the release agent composition C was applied to one side of a liner substrate (Lumirror 38R75, a polyester film, thickness 38 μm) with a wire bar and heated at 130 ° C. for 1 minute to produce a release liner C having a release layer (thickness 100 nm) on one side.

[0110] (Production Example 5: Production of Release Liner D) Addition reaction curing type silicone (KS-847H containing vinyl group-containing polyorganosiloxane, 30 wt% toluene solution, Shin-Etsu Chemical Co., Ltd.) 66.6 parts by weight, curing catalyst (CAT-PL-50T containing platinum catalyst, Shin-Etsu Chemical Co., Ltd.) 0.2 parts by weight, and toluene / hexane mixed solvent (volume ratio 1: 1) as a dilution solvent were mixed to obtain a silicone-based release agent composition D. The concentration of silicone solids in the release agent composition D was 1.0 wt%. Next, the release agent composition D was applied to one side of a liner substrate (Lumirror 38R75, a polyester film, thickness 38 μm) with a wire bar and heated at 130 ° C. for 1 minute to produce a release liner D having a release layer (thickness 100 nm) on one side.

[0111] [Peeling force PS 0 Evaluation The photocurable composition of Production Example 1 was applied to one side of a substrate sheet (Lumirror 38R75, a polyester film having no release layer, thickness 38 μm) using an applicator to form a coating layer. Next, each of the release liners of Production Examples 2 to 5 was placed on the formed coating layer to obtain a first laminate. The release liner was placed so that the release layer was in contact with the coating layer. Next, a light with an illuminance of 2.4 mW / cm was applied from the release liner side of the first laminate. 2 and cumulative light intensity of 2880mJ / cm 2The coating layer was photocured by irradiating it with ultraviolet light (black light source) under the conditions above to form a second laminate a composed of the base sheet, the adhesive sheet (thickness 20 μm), and the release liner.

[0112] A test piece having a length of 220 mm and a width of 50 mm (the length direction was the coating direction of the photocurable composition) was cut out from the formed second laminate a. The entire surface of the test piece on the side of the base sheet was fixed to a SUS plate as a fixing plate, and a 180° peel test was carried out by peeling only the release liner in the length direction using a tensile tester. The peel strength PS 0 The peel test conditions were as described above.

[0113] [Peeling force PS 1 , P.S. 2 , P.S. 3 Evaluation A portion of the second laminate a in the longitudinal direction was cut and removed so as not to include the location from which the test specimen was taken, and the release liner was peeled off for reuse. A second laminate b was formed in the same manner as in the formation of the second laminate a, except that the peeled release liner was used. The peel force PS 0 The peel strength was evaluated in the same manner as in the evaluation of PS 1 Next, the release liner was peeled off from the second laminate a, and the peeled release liner was reused to form the second laminate b in the same manner as above, to form a second laminate c (reused for the second time) from the second laminate b, and a second laminate d (reused for the third time) from the second laminate c. The peel force PS 0 The peel strength PS 2 and P.S. 3 was evaluated.

[0114] [Evaluation of the ease of peeling off the release liner when only the edge is fixed (ease of peeling)] For the second laminate d, both ends in the length direction were fixed to a fixed surface with double-sided adhesive tape on the base sheet side, and the release liner was peeled off from one of the ends. Depending on the state of the peeling, the ease of peeling was evaluated as follows. A: The unfixed portion of the second laminate did not lift off from the fixing surface, and the release liner could be easily peeled off. B: The unfixed portion of the second laminate was slightly lifted from the fixed surface, but the release liner could be peeled off. C: The unfixed portion of the second laminate rose from the fixing surface, making it difficult to peel off the release liner.

[0115] The evaluation results of the release force and ease of peeling for each release liner are shown in Table 1 below.

[0116] [Table 1] [Industrial Applicability]

[0117] 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. [Explanation of symbols]

[0118] 1 Adhesive sheet 2,2A,2B Optical Film 10 (First) Laminate 11 Base sheet 12 Coating layer 13 Release Liner 131 Liner base material 132 Release layer 14 light 18 Exposed surface 21,22 Optical film with adhesive sheet

Claims

1. A step A of irradiating a laminate including a base sheet, a coating layer including a photocurable composition, and the release liner in this order with light using a release liner to form a pressure-sensitive adhesive sheet from the coating layer; and step B of peeling the release liner from the pressure-sensitive adhesive sheet, The steps A and B are repeatedly performed using the release liner peeled off in the step B, The release liner was peeled from the adhesive sheet three times, counting from an unused state, and then the peel strength PS 3 Use a sheet having a strength of less than 1.0 N / 50 mm; A method for manufacturing an adhesive sheet.

2. The release liner has a peel strength (PS) between the release liner and the pressure-sensitive adhesive sheet, which is measured in an unused state. 0 The method for producing a pressure-sensitive adhesive sheet according to claim 1 , wherein the tension is 0.01 N / 50 mm or more.

3. The release liner has a peel strength (PS) between the release liner and the pressure-sensitive adhesive sheet, which is measured in an unused state. 0 The peel force PS 3 Comparison of PS 3 / PS 0 The method for producing a pressure-sensitive adhesive sheet according to claim 1 , wherein the σ is 10 or less.

4. The release liner has a peel strength (PS) between the release liner and the pressure-sensitive adhesive sheet, which is measured in an unused state. 0 The peel strength PS between the adhesive sheet and the adhesive sheet was measured after peeling it once from the adhesive sheet, counting from the unused state. 1 Comparison of PS 1 / PS 0 The method for producing a pressure-sensitive adhesive sheet according to claim 1 , wherein the σ is 10 or less.

5. the release liner has a release layer on the surface of the coating layer; The method for producing a pressure-sensitive adhesive sheet according to claim 1 , wherein the release layer has a thickness of 110 nm or less.

6. The method for producing a pressure-sensitive adhesive sheet according to claim 1 , wherein a peel strength between the release liner and the pressure-sensitive adhesive sheet is smaller than a peel strength between the base sheet and the pressure-sensitive adhesive sheet.

7. The method for producing a pressure-sensitive adhesive sheet according to claim 1 , wherein the photocurable composition comprises a monomer group including a (meth)acrylic monomer and / or a partial polymer of the monomer group.

8. The method for producing a pressure-sensitive adhesive sheet according to claim 7 , wherein the (meth)acrylic monomer comprises a carboxyl group-containing monomer.

9. A method for producing an optical film with a pressure-sensitive adhesive sheet, comprising: arranging an optical film on an exposed surface of the pressure-sensitive adhesive sheet formed by the manufacturing method according to any one of claims 1 to 8 to form an optical film with a pressure-sensitive adhesive sheet.

10. The method for producing an optical film with a pressure-sensitive adhesive sheet according to claim 9 , wherein the optical film comprises at least one film selected from the group consisting of a polarizing film and a retardation film.

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