JP2024014617A - Manufacturing method of pressure sensitive adhesive sheet and manufacturing method of optical film having pressure sensitive adhesive sheet - Google Patents

Abstract

PROBLEM TO BE SOLVED: 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

COPYRIGHT: (C)2024,JPO&INPIT

Description

The present invention relates to a method for manufacturing an adhesive sheet 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.

JP2016-155981A

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
Step A of irradiating a laminate including a base sheet, a coating layer containing a photocurable composition, and the release liner in this order using a release liner to form an adhesive sheet from the coating layer;
Step B of peeling off the release liner from the adhesive sheet,
The step A and the step B are repeatedly performed using the release liner peeled off in the step B,
As the release liner, use a sheet whose peel force PS ₃ with the adhesive sheet is less than 1.0 N/50 mm, measured after peeling from the adhesive sheet three times from the unused state.
Method for manufacturing adhesive sheet,
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:
Step A of irradiating a laminate including a base sheet, a coating layer containing a photocurable composition, and the release liner in this order using a release liner to form an adhesive sheet from the coating layer;
Step B of peeling off the release liner from the adhesive sheet,
The step A and the step B are repeatedly performed using the release liner peeled off in the step B,
As the release liner, a sheet is used that has a peeling force PS ₃ of less than 1.0 N/50 mm with respect to the adhesive sheet, which is measured after peeling from the adhesive sheet three times, counting from the unused state.

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 release liner has a peel force PS ₀ of 0.01 N/50 mm or more with respect to the pressure-sensitive adhesive sheet when measured in an unused state.

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 release liner has a ratio PS ₃ /PS ₀ of the release force PS ₃ to the release force PS ₀ with respect to the pressure-sensitive adhesive sheet, measured in an unused state, of 10 or less.

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 release liner has a peeling force PS 0 with the adhesive sheet measured in an unused state versus a peeling force PS ₀ with the adhesive sheet measured after peeling the adhesive sheet once from the unused state. The ratio PS ₁ /PS ₀ of ₁ is 10 or less.

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 release liner includes a release layer on a side of the coating layer,
The thickness of the release layer is 110 nm or less.

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 peeling force between the release liner and the adhesive sheet is smaller than the peeling force between the base sheet and the adhesive sheet.

In the seventh 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 sixth aspects,
The photocurable composition contains a monomer group containing a (meth)acrylic monomer and/or a partial polymer of the monomer group.

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

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 arranging an optical film on the exposed surface of a pressure-sensitive adhesive sheet formed by the method for manufacturing a pressure-sensitive adhesive sheet according to any one of the first to eighth aspects to form an optical film with a pressure-sensitive adhesive sheet.

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. On the other hand, according to studies by the present inventors, the degree of increase in peeling force tends to decrease as the number of peeling increases. The peeling force PS ₃ after peeling from the pressure-sensitive adhesive sheet three times from the unused state is useful as an index reflecting the increase in peeling force. Release liners with a release force PS ₃ of less than 1.0 N/50 mm are suitable for repeated use. The more the release liner is used repeatedly, the less release liner will be discarded, and the environmental impact will 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, 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 separate the adhesive sheet 1 from the coating layer 12. Form (Step A). The light 14 passes through the release liner 13, reaches the coating layer 12, and cures the coating layer 12. However, the light 14 may be irradiated from the base sheet 11 side, or from both sides of the release liner 13 and the base sheet 11. In step A, the adhesive sheet 1 is formed using the release liner 13. The formed adhesive sheet 1 is sandwiched between the base sheet 11 and the release liner 13 and constitutes 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 adhesive sheet 1 (step B). In the method of FIG. 1, using the release liner 13 peeled off in step B, steps A and B are repeatedly performed. In step A using the released release liner 13, a first laminate 10 including the base sheet 11, the coating layer 12, and the released release liner 13 in this order is formed, and the formed first laminate is 10 is irradiated with light 14.

In the method of FIG. 1, the release liner 13 is a sheet whose peel force PS ₃ with the adhesive sheet 1 is less than 1.0 N/50 mm as measured after peeling from the adhesive sheet 1 three times from the unused state. use As Step A is carried out, the peeling force of the release liner 13 against the adhesive sheet 1 usually increases. It is presumed that the increase in peeling force is due to an increase in the amount of functional groups and radicals present on the surface of the release liner 13 on the side of the coating layer 12 due to the irradiation with the light 14. The above increase is due to the fact that a chemical bond is formed between the release liner 13 and the adhesive sheet 1 due to the irradiation of the light 14, and some of the bonds and groups formed by decomposition of the bond remain on the surface even after the adhesive sheet 1 is peeled off. This may be caused by residual substances.

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

The release liner 13 may have a peel force PS ₀ of 0.01 N/50 mm or more, 0.02 N/50 mm or more, and more preferably 0.03 N/50 mm or more, when measured in an unused state. There may be. The upper limit of the peeling force PS ₀ is, for example, 0.2 N/50 mm or less, 0.17 N/50 mm or less, 0.15 N/50 mm or less, 0.12 N/50 mm or less, and further 0.1 N/50 mm or less. Good too.

The release liner 13 may have a ratio PS 3 /PS 0 of release force PS ₃ to the release force PS ₀ with respect to the adhesive sheet 1 measured in an unused state, PS ₃ /PS ₀ , of 10 or less, 7 or less, 5 or less, 4 or less. , 3 or less, 2 or less, or even 1.8 or less. The lower limit of the ratio PS ₃ /PS ₀ is, for example, 1.1 or more, more preferably 1.2 or more.

The release liner 13 has a peeling force PS 0 with the adhesive sheet 1 measured in an unused state and a peeling force PS ₀ with the adhesive sheet 1 measured after being peeled once from the adhesive sheet 1 counting from the unused state. The ratio PS ₁ /PS ₀ of ₁ 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. The lower limit of the ratio PS ₁ /PS ₀ is, for example, 1.05 or more, more preferably 1.1 or more.

Peeling force PS n after peeling n times from the adhesive sheet 1 counting from the unused state ( _n is an integer greater than or equal to 0 corresponding to the number of peels; when n = 0, the peeling force PS ₀ in the unused state ) is a test piece by performing Step A and Step B n times using the release liner to be evaluated, and then cutting out the second laminate 17 formed by performing Step A for the (n+1)th time to a width of 50 mm. can be evaluated by performing a 180° peel test in which only the release liner 13 is peeled off from the prepared test piece. The peel test is carried out after approximately 0.5 to 1 hour has elapsed from the formation of the adhesive sheet 1. From the formation of the adhesive sheet 1 to the implementation 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, after fixing the entire surface of the test piece on the base sheet 11 side to a fixing plate (for example, a SUS plate) with double-sided adhesive tape, one longitudinal end of the fixing plate was subjected to a tensile test. This can be carried out by fixing the liner to the upper chuck of a tensile testing machine, peeling off the end of the release liner 13 on the upper chuck side, folding it back 180°, and fixing it to the lower chuck of a tensile testing machine. As the fixing plate, one having sufficient mechanical strength to stably perform the peel test can be used. The double-sided adhesive tape may have sufficient adhesive strength to prevent the base sheet 11 from being peeled off from the fixed plate during the peel test. 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 second laminate 17 is less than 50 mm, the measured value at the original width may be converted to a value per 50 mm width. When the direction in which the coating layer 12 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 base sheet 11 and release liner 13 are elongated, the width direction thereof can be the width direction of the test piece.

The peeling force PS ₀ , PS _n and the degree of increase in PS _n by repeating peeling depend on, for example, the composition of the photocurable composition, the composition, formation conditions and thickness of the pressure-sensitive adhesive sheet 1 to be formed, and the material of the release liner 13. , the thickness and condition of the release surface, and the composition, formation conditions, and thickness of the release layer that the release liner 13 may include.

An example of the base material of the release liner 13 (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 release liner 13 has excellent transparency for the light 14 irradiated in step A.

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

Release liner 13 may include layers other than the liner base material. The release liner 13 may include a release layer. The release liner 13 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 release liner 13 shown in FIG. 2 can be used so that the release layer 132 is on the coating layer 12 side.

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 release liner 13 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"). The silicone release layer is particularly suitable for achieving both adhesion and releasability to the acrylic pressure-sensitive adhesive sheet 1. 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. The addition reaction-curable silicone material is particularly suitable for forming a release layer that has both adhesion and releasability to the acrylic pressure-sensitive 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.

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 such as 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 thickness of the release layer 132 may be 110 nm or less; in other words, the release liner 13 may include the release layer 132 on the surface facing the coating layer 12, and the thickness of the release layer 132 may be 110 nm or less. There may be.

The release liner 13 may be sheet-like or elongated.

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

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

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

The base sheet 11 may include a release layer on the surface facing the coating layer 12 . Examples of the release layer that the base sheet 11 can include and its manufacturing method are the same as the examples of the release layer that the release liner 13 can include and its manufacturing method. Both the release liner 13 and the base sheet 11 may be provided with 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 base sheet 11 may be thicker.

As the base sheet 11, a sheet can usually be selected that has a greater peel strength with respect to the adhesive sheet 1 than the release liner 13.

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

(Photocurable composition)
The photocurable composition is a composition from which the adhesive sheet 1 can be formed from the coating layer 12 by irradiation with the light 14. The 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 photocurable composition, that is, the (meth)acrylic monomer and its partial polymer, is 50% by weight or more, 60% by weight or more, 70% by weight or more, and even The content may be 80% by weight or more, and in this case, an acrylic pressure-sensitive adhesive sheet 1 containing a (meth)acrylic polymer and a crosslinked product thereof as main components can be formed. However, the 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 rate of polymerization and curing of a carboxyl group-containing monomer by irradiation with light 14 is usually higher than that of a (meth)acrylic acid alkyl ester that does not contain a carboxyl group. The high speed means that while the elastic modulus of the pressure-sensitive adhesive sheet 1 can be increased and the dimensional stability against deformation force can be improved, the peeling force of the release liner against the pressure-sensitive adhesive sheet 1 tends to be large. Therefore, the use of the release liner 13 with suppressed release force PS ₃ is particularly advantageous when the photocurable composition contains a carboxyl group-containing monomer.

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. The hydroxy group-containing monomer can contribute to improving the cohesive force of the pressure-sensitive adhesive sheet 1. 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 photocurable composition, each of the monomers mentioned above 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 coating layer 12 by appropriately increasing the viscosity of the photocurable composition.

A 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 photocurable composition is, for example, 0.02 to 10 parts by weight, and 0.05 to 5 parts by weight, based on a total of 100 parts by weight of the monomer group and its partial polymer. It may be a department.

The 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 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 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 or less. It's okay. The 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 photocurable composition is preferably 5 to 100 poise. A photocurable composition having a viscosity within the above range is particularly suitable for forming the coating layer 12.

(First laminate and its formation)
The first laminate 10 may include further layers other than the base sheet 11, the coating layer 12, and the release liner 13. The further layer may be arranged 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.

The first laminate 10 is constructed by, for example, forming a coating layer 12 on a base sheet 11 (or a release liner 13), and disposing a release liner 13 (or a base sheet 11) on the formed coating layer 12. It can be formed by Further, the first laminate 10 is formed by pouring and applying the photocurable composition into the space between the base sheet 11 and the release liner 13 which are held at a predetermined interval so that their main surfaces face each other. You may. The peeled release liner 13 may be used so that the surface that was on the coating layer 12 side in step A immediately before peeling, for example, the surface on the release layer 132 side, becomes the coating layer 12 side again. .

The coating layer 12 can be formed using a roll coat, a kiss roll coat, a gravure coat, a reverse coat, a roll brush, a spray coat, a dip roll coat, a bar coat, a knife coat, an air knife coat, a curtain coat, a lip coat, a die coat, etc. Various application methods can be applied.

The thickness of the coating layer 12 can be adjusted depending on the desired thickness of the 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.

The first laminate 10 may include an elongated base sheet 11, an elongated coating layer 12, and an elongated release liner 13; in other words, even if it is elongated, good. The elongated first laminate 10 can be obtained, for example, by forming the coating layer 12 between the base sheet 11 and the release liner 13 that have been unwound from the roll while being conveyed.

(Light irradiation)
The light 14 irradiated onto the first laminate 10 is, for example, visible light or ultraviolet light having a wavelength shorter than 450 nm. The light 14 may include light with a wavelength in the same region as the absorption wavelength of the photopolymerization initiator included in the photocurable composition. The light 14 may be irradiated by cutting short wavelength light of 300 nm or less with a filter or the like, and cutting off the short wavelength light is suitable for suppressing deterioration of the release liner 13 due to the light 14. The light source of the light 14 is, for example, a light irradiation device including an ultraviolet irradiation lamp. Examples of ultraviolet irradiation lamps include 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.

Irradiation of the light 14 may be continuous or intermittent.

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

The polymerization rate of the monomer group in the adhesive sheet 1 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 adhesive sheet 1 is, for example, 50% or more, and may be 75% or more, 80% or more, or even 85% or more.

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

The peeling force between the release liner 13 and the adhesive sheet 1 may be smaller than the peeling force between the base sheet 11 and the adhesive sheet 1.

The peeling force of the base sheet 11 to the 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.

The number of times the release liner 13 is peeled off and reused for manufacturing 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 no particular restriction on the upper limit of the number of times, and for example, use may be continued as long as the peeling force PS _n with the adhesive sheet 1 does not exceed 3.0 N/50 mm.

The peeled release liner 13 may be reused after being wound up into a rolled body.

The thickness of the 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.

The adhesive sheet 1 can be used, for example, in an optical laminate including an optical film. In other words, the adhesive sheet 1 may be used for optical laminates. The optical laminate may be an optical film with an adhesive sheet. However, the use of the adhesive sheet 1 is 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, a coating layer 12 of a photocurable composition is formed on one side of a long base sheet 11 fed out from a roll 31 using a coating device 32 . Next, the elongated release liner 13 unwound from the rolled body 33 is placed on the coating layer 12 to form the elongated first laminate 10. Next, the first laminate 10 is irradiated with light 14 from the light irradiation device 34 to form the elongated adhesive sheet 1. Next, the release liner 13 is peeled off from the second laminate 17 including the adhesive sheet 1 and wound up into a roll 35 . The above steps are performed while conveying the base sheet 11 and release liner 13. The rolled-up release liner 13 is reused. The third laminate 15 formed by peeling off the release liner 13 can be used, for example, to produce an optical film with an adhesive sheet or the production thereof. The method shown in FIG. 3 is particularly suitable for mass production of the adhesive sheet 1.

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 shown in FIG. 3, except that the release liner 13 peeled off from the second laminate 17 is not wound up into the roll 35 and is reused for manufacturing the adhesive sheet 1. The method shown in FIG. 4 is particularly suitable for mass production of the adhesive sheet 1.

[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 producing 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, an optical film 2 is attached to the exposed surface 18 of the adhesive sheet 1, which is formed by peeling the release liner 13 from the second laminate 17 that includes the base sheet 11, the adhesive sheet 1, and the release liner 13 in this order. are arranged to form an optical film 21 with an adhesive sheet. Optical film with adhesive sheet 21 includes base sheet 11, adhesive sheet 1, and optical film 2 in this order. The second laminate 17 can be formed by the above step A. Peeling of the release liner 13 may be performed as step B above. The adhesive sheet-attached optical film 21 can be used as it is or after peeling off the base sheet 11, 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 adhesive sheet-attached optical film 21 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 the base sheet 11 from the optical film 21 with an adhesive sheet. For example, the optical film 2A, the adhesive sheet 1, and the optical film An optical film 22 with an adhesive sheet containing 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 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, a long optical film 2 is placed on the exposed surface 18 of the adhesive sheet 1 in the third laminate 15 formed by the method shown in 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 1 and the formation of the adhesive sheet-attached optical film 21 may be performed continuously. The method shown in FIG. 7 is particularly suitable for mass production of the optical film 21 with adhesive sheet.

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 attached to one main surface of a polarizer via an adhesive, and a protective film made of a thermosetting resin or an 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 21 and 22 with adhesive sheets and an image display panel. The bonding may be performed using the 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 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.

(Production Example 5: Production of release liner D)
66.6 parts by weight of addition reaction-curing silicone (KS-847H 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-based mold release agent composition D was obtained by mixing 0.2 parts by weight of the silicone-based mold release agent composition D) and a toluene/hexane mixed solvent (volume ratio 1:1) as a diluent solvent. The concentration of silicone solids in mold release agent composition D was 1.0% by weight. Next, mold release agent composition D was applied to one side of the liner base material (Lumirror 38R75, a polyester film, thickness 38 μm) using a wire bar, and heated at 130° C. for 1 minute to form a mold release layer (100 nm thick). ) was prepared on one side.

[Evaluation of peeling force PS ₀ ]
The photocurable composition of Production Example 1 was applied to one side of a base sheet (Lumirror 38R75, a polyester film without a release layer, thickness 38 μm) using an applicator to form a coating layer. Next, each release liner 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, from the release liner side of the first laminate, ultraviolet rays (black light source) are irradiated with an illuminance of 2.4 mW/cm ² and an integrated light amount of 2880 mJ/cm ² to photocure the coating layer, A second laminate a was formed consisting of a base sheet, an adhesive sheet (thickness: 20 μm), and a release liner.

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 second laminate a. A 180° peel test was conducted using a tensile testing machine to peel off only the release liner in the length direction on a test piece whose entire side surface of the base sheet was fixed to a SUS plate that was a fixing plate. , the peeling force PS ₀ was evaluated. The conditions for the peel test were as described above.

[Evaluation of peeling force PS ₁ , PS ₂ , PS ₃ ]
A portion of the second laminate a in the length direction was removed by cutting so as not to include the sampled portion of the test piece, and then the release liner was peeled off for reuse. A second laminate b was formed in the same manner as the second laminate a, except that a peeled release liner was used. The peel force PS _{1 was evaluated in the same manner as the evaluation of the peel force PS 0 except} that a test piece cut out from the second laminate b was used as the evaluation target. Next, the release liner is peeled off from the second laminate a, and the second laminate b is removed from the second laminate b in the same manner as described above, in which the peeled release liner is reused to form the second laminate b. A laminate c (second reuse) was formed, and a second laminate d (third reuse) was formed from the second laminate c. Peeling forces PS 2 and PS 3 were evaluated in the same manner as in the evaluation of peeling force PS ₀ , except that test pieces cut out from the second laminate _c and the _second laminate d were evaluated.

[Evaluation of ease of peeling of the release liner with only the ends fixed (peelability)]
With respect to the second laminate d, the release liner was peeled off from one of the end portions while only each of both end portions in the length direction was fixed to the fixing surface with double-sided adhesive tape on the side of the base sheet. Depending on the state of peeling, ease of peeling was determined as follows.
A: The release liner could be easily peeled off without the unfixed portion of the second laminate rising from the fixing surface.
B: The part of the second laminate that was not fixed 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.

The evaluation results of release force and ease of release for each release liner are shown in Table 1 below.

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.

1 Adhesive sheets 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 surfaces 21, 22 Optical film with adhesive sheet

Claims (10)

Step A of irradiating a laminate including a base sheet, a coating layer containing a photocurable composition, and the release liner in this order using a release liner to form an adhesive sheet from the coating layer;
Step B of peeling off the release liner from the adhesive sheet,
The step A and the step B are repeatedly performed using the release liner peeled off in the step B,
As the release liner, use a sheet whose peel force PS ₃ with the adhesive sheet is less than 1.0 N/50 mm, measured after peeling from the adhesive sheet three times from the unused state.
Method for manufacturing adhesive sheets. The method for producing a pressure-sensitive adhesive sheet according to claim 1, wherein the release liner has a peeling force PS ₀ of 0.01 N/50 mm or more with respect to the pressure-sensitive adhesive sheet when measured in an unused state. The production of the pressure-sensitive adhesive sheet according to claim 1, wherein the release liner has a ratio PS ₃ /PS _{0 of the release force PS 3 to} the release force PS ₀ with the pressure-sensitive adhesive sheet measured in an unused state of 10 or less. Method. The release liner has a peeling force PS 0 with the adhesive sheet measured in an unused state versus a peeling force PS ₀ with the adhesive sheet measured after peeling the adhesive sheet once from the unused state. The method for producing a pressure-sensitive adhesive sheet according to claim ₁ , wherein the ratio PS ₁ /PS ₀ of 1 is 10 or less. The release liner includes a release layer on a side of the coating layer,
The method for producing a pressure-sensitive adhesive sheet according to claim 1, wherein the thickness of the release layer is 110 nm or less. The method for producing a pressure-sensitive adhesive sheet according to claim 1, wherein a peeling force between the release liner and the pressure-sensitive adhesive sheet is smaller than a peeling force between the base sheet and the pressure-sensitive adhesive sheet. The method for producing a pressure-sensitive adhesive sheet according to claim 1, wherein the photocurable composition contains 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 7, wherein the (meth)acrylic monomer includes a carboxyl group-containing monomer. 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 8. 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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