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WO2022244556A1 - Adhesive agent composition, adhesive sheet, optical laminate, and image display device - Google Patents

Adhesive agent composition, adhesive sheet, optical laminate, and image display device Download PDF

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Publication number
WO2022244556A1
WO2022244556A1 PCT/JP2022/017651 JP2022017651W WO2022244556A1 WO 2022244556 A1 WO2022244556 A1 WO 2022244556A1 JP 2022017651 W JP2022017651 W JP 2022017651W WO 2022244556 A1 WO2022244556 A1 WO 2022244556A1
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WO
WIPO (PCT)
Prior art keywords
weight
pressure
meth
sensitive adhesive
adhesive sheet
Prior art date
Application number
PCT/JP2022/017651
Other languages
French (fr)
Japanese (ja)
Inventor
潤枝 長田
悟士 山本
雄祐 外山
Original Assignee
日東電工株式会社
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by 日東電工株式会社 filed Critical 日東電工株式会社
Priority to CN202280036387.9A priority Critical patent/CN117355588A/en
Priority to KR1020237043390A priority patent/KR20240012452A/en
Publication of WO2022244556A1 publication Critical patent/WO2022244556A1/en

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    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09J—ADHESIVES; NON-MECHANICAL ASPECTS OF ADHESIVE PROCESSES IN GENERAL; ADHESIVE PROCESSES NOT PROVIDED FOR ELSEWHERE; USE OF MATERIALS AS ADHESIVES
    • C09J133/00—Adhesives based on homopolymers or copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and at least one being terminated by only one carboxyl radical, or of salts, anhydrides, esters, amides, imides, or nitriles thereof; Adhesives based on derivatives of such polymers
    • C09J133/04—Homopolymers or copolymers of esters
    • C09J133/06—Homopolymers or copolymers of esters of esters containing only carbon, hydrogen and oxygen, the oxygen atom being present only as part of the carboxyl radical
    • C09J133/08—Homopolymers or copolymers of acrylic acid esters
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B27/00—Layered products comprising a layer of synthetic resin
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B27/00—Layered products comprising a layer of synthetic resin
    • B32B27/30—Layered products comprising a layer of synthetic resin comprising vinyl (co)polymers; comprising acrylic (co)polymers
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B7/00—Layered products characterised by the relation between layers; Layered products characterised by the relative orientation of features between layers, or by the relative values of a measurable parameter between layers, i.e. products comprising layers having different physical, chemical or physicochemical properties; Layered products characterised by the interconnection of layers
    • B32B7/02—Physical, chemical or physicochemical properties
    • B32B7/023—Optical properties
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B7/00—Layered products characterised by the relation between layers; Layered products characterised by the relative orientation of features between layers, or by the relative values of a measurable parameter between layers, i.e. products comprising layers having different physical, chemical or physicochemical properties; Layered products characterised by the interconnection of layers
    • B32B7/04—Interconnection of layers
    • B32B7/12—Interconnection of layers using interposed adhesives or interposed materials with bonding properties
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09J—ADHESIVES; NON-MECHANICAL ASPECTS OF ADHESIVE PROCESSES IN GENERAL; ADHESIVE PROCESSES NOT PROVIDED FOR ELSEWHERE; USE OF MATERIALS AS ADHESIVES
    • C09J11/00—Features of adhesives not provided for in group C09J9/00, e.g. additives
    • C09J11/02—Non-macromolecular additives
    • C09J11/06—Non-macromolecular additives organic
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09J—ADHESIVES; NON-MECHANICAL ASPECTS OF ADHESIVE PROCESSES IN GENERAL; ADHESIVE PROCESSES NOT PROVIDED FOR ELSEWHERE; USE OF MATERIALS AS ADHESIVES
    • C09J133/00—Adhesives based on homopolymers or copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and at least one being terminated by only one carboxyl radical, or of salts, anhydrides, esters, amides, imides, or nitriles thereof; Adhesives based on derivatives of such polymers
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09J—ADHESIVES; NON-MECHANICAL ASPECTS OF ADHESIVE PROCESSES IN GENERAL; ADHESIVE PROCESSES NOT PROVIDED FOR ELSEWHERE; USE OF MATERIALS AS ADHESIVES
    • C09J175/00—Adhesives based on polyureas or polyurethanes; Adhesives based on derivatives of such polymers
    • C09J175/04—Polyurethanes
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09J—ADHESIVES; NON-MECHANICAL ASPECTS OF ADHESIVE PROCESSES IN GENERAL; ADHESIVE PROCESSES NOT PROVIDED FOR ELSEWHERE; USE OF MATERIALS AS ADHESIVES
    • C09J7/00—Adhesives in the form of films or foils
    • C09J7/30—Adhesives in the form of films or foils characterised by the adhesive composition
    • C09J7/38—Pressure-sensitive adhesives [PSA]
    • C09J7/381—Pressure-sensitive adhesives [PSA] based on macromolecular compounds obtained by reactions involving only carbon-to-carbon unsaturated bonds
    • C09J7/385—Acrylic polymers
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B5/00—Optical elements other than lenses
    • G02B5/30—Polarising elements
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B2457/00—Electrical equipment
    • B32B2457/20—Displays, e.g. liquid crystal displays, plasma displays

Definitions

  • the present invention relates to an adhesive composition, an adhesive sheet, an optical laminate, and an image display device.
  • image display devices typified by liquid crystal display devices and electroluminescence (EL) display devices (eg, organic EL display devices and inorganic EL display devices) have rapidly spread.
  • These various image display devices usually have a laminated structure of an image forming layer such as a liquid crystal layer and an EL light emitting layer, and an optical laminate including an optical film and an adhesive sheet.
  • the pressure-sensitive adhesive sheet is mainly used for bonding between films included in the optical layered body and bonding between the image forming layer and the optical layered body.
  • the optical film are a polarizing plate, a retardation film, and a polarizing plate with a retardation film in which the polarizing plate and the retardation film are integrated.
  • Patent Literature 1 discloses an example of an optical laminate.
  • An object of the present invention is to provide a pressure-sensitive adhesive composition suitable for forming a pressure-sensitive adhesive sheet that can suppress changes in the dimensions of the optical film contained in the optical laminate and also ensures durability.
  • the present invention A pressure-sensitive adhesive composition containing a (meth)acrylic polymer (A) as a main component, further comprising a cross-linking agent (B),
  • a pressure-sensitive adhesive composition containing a (meth)acrylic polymer (A) as a main component, further comprising a cross-linking agent (B)
  • B cross-linking agent
  • the gel fraction G 2h of the pressure-sensitive adhesive sheet is less than 60% by weight at the time when 2 hours have passed since the time T 0 of forming the pressure-sensitive adhesive sheet
  • the pressure-sensitive adhesive composition, wherein the gel fraction G 24h of the pressure-sensitive adhesive sheet 24 hours after the time T 0 is 60% by weight or more, I will provide a.
  • the invention provides a A pressure-sensitive adhesive sheet formed from the pressure-sensitive adhesive composition of the present invention, I will provide a.
  • the invention provides a An optical laminate comprising the adhesive sheet of the present invention and an optical film, I will provide a.
  • the invention provides a an image display device comprising the optical layered body of the present invention; I will provide a.
  • the pressure-sensitive adhesive composition according to the present invention is suitable for forming a pressure-sensitive adhesive sheet that can suppress changes in the dimensions of the optical film contained in the optical layered body and also ensures durability.
  • FIG. 1 is a cross-sectional view schematically showing an example of the pressure-sensitive adhesive sheet of the present invention.
  • FIG. 2 is a cross-sectional view schematically showing an example of the optical layered body of the present invention.
  • FIG. 3 is a cross-sectional view schematically showing an example of the optical layered body of the present invention.
  • FIG. 4 is a cross-sectional view schematically showing an example of the optical layered body of the present invention.
  • FIG. 5 is a cross-sectional view schematically showing an example of the optical layered body of the present invention.
  • FIG. 6 is a cross-sectional view schematically showing an example of the image display device of the present invention.
  • (Meth)acrylic as used herein means acrylic and methacrylic. Moreover, “(meth)acrylate” means acrylate and methacrylate.
  • the pressure-sensitive adhesive composition (I) of the present embodiment contains a (meth)acrylic polymer (A) and a cross-linking agent (B).
  • the (meth)acrylic polymer (A) is contained in the pressure-sensitive adhesive composition (I) as a main component.
  • the pressure-sensitive adhesive composition (I) is an acrylic pressure-sensitive adhesive composition.
  • a main component means the component with the largest content rate also in a composition.
  • the content of the main component is, for example, 50% by weight or more, and may be 60% by weight or more, 70% by weight or more, 73% by weight or more, or even 75% by weight or more.
  • the gel fraction G 2h of the pressure-sensitive adhesive sheet after 2 hours from the time T 0 of forming the pressure-sensitive adhesive sheet is less than 60% by weight.
  • the gel fraction G 24h of the pressure-sensitive adhesive sheet after 24 hours from time T 0 is 60% by weight or more.
  • the above range of the gel fraction G 2h indicates that the cross-linking reaction in forming the pressure-sensitive adhesive sheet from the pressure-sensitive adhesive composition (I) proceeds relatively slowly in the initial stage from T 0 to 2 hours. means.
  • the suppressed speed of cross-linking in the initial stage enhances the uniformity of the crosslinked structure in the pressure-sensitive adhesive sheet, and the enhanced uniformity contributes to the improvement of the durability of the pressure-sensitive adhesive sheet. Further, the gel fraction G24h being within the above range contributes to suppression of dimensional change of the optical film included in the optical layered body.
  • the gel fraction G2h is 55% by weight or less, less than 55% by weight, 50% by weight or less, 47% by weight or less, 45% by weight or less, less than 45% by weight, 40% by weight or less, 35% by weight or less, and 30% by weight. 25% by weight or less, 20% by weight or less, 15% by weight or less, 14% by weight or less, 13% by weight or less, or even 12% by weight or less.
  • the lower limit of the gel fraction G 2h is, for example, 2% by weight or more, 4% by weight or more, 5% by weight or more, 7% by weight or more, 8% by weight or more, 9% by weight or more, 9.5% by weight or more, and further may be 9.7% by weight or more.
  • the gel fraction G24h may be 65% by weight or more, 70% by weight or more, 75% by weight or more, 80% by weight or more, 90% by weight or more, 92% by weight or more, or even 94% by weight or more.
  • the upper limit of the gel fraction G24h is, for example, 99% by weight or less, and may be 98% by weight or less, 97% by weight or less, or even 96% by weight or less.
  • the ratio G 24h /G 2h of the gel fraction G 24h to the gel fraction G 2h is, for example, 2 or more, and may be 3 or more, 4 or more, 5 or more, 6 or more, 7 or more, or even 8 or more.
  • the upper limit of the ratio G 24h /G 2h is, for example, 48 or less, 45 or less, 40 or less, 35 or less, 30 or less, 25 or less, 20 or less, 15 or less, 10 or less, or even 9.7 or less. good.
  • the gel fraction G 0 of the pressure-sensitive adhesive sheet immediately after the time T 0 of forming the pressure-sensitive adhesive sheet may be 3% by weight or more and 50% by weight or less. Immediately after is typically within 10 minutes from time T 0 , and may be within 5 minutes.
  • the upper limit of the gel fraction G 0 is 45% by weight or less, 40% by weight or less, 35% by weight or less, 30% by weight or less, 25% by weight or less, 20% by weight or less, 15% by weight or less, 10% by weight or less, 8 % by weight or less, 6% by weight or less, or even 5% by weight or less.
  • the ratio G 2h /G 0 of the gel fraction G 2h to the gel fraction G 0 is, for example, less than 20, 15 or less, 10 or less, 6 or less, 5 or less, 4 or less, 3 or less, 2.5 or less, 2 .4 or less, or even 2.3 or less.
  • the lower limit of the ratio G 2h /G 0 is, for example, 1 or more, more than 1, 1.1 or more, 1.2 or more, 1.5 or more, 1.7 or more, 2 or more, and further 2.1 or more.
  • the gel fraction G 7d of the pressure-sensitive adhesive sheet after 7 days have passed from time T 0 may be 90% by weight or more, 91% by weight or more, 92% by weight or more, 93% by weight or more, 94% by weight or more. Furthermore, it may be 95% by weight or more.
  • the upper limit of G7d is, for example, 99.5% by weight or less, and may be 99% by weight or less, or even 98% by weight or less.
  • the ratio G 7d /G 24h of the gel fraction G 7d to the gel fraction G 24h is, for example, 1.5 or less, 1.4 or less, 1.3 or less, 1.2 or less, 1.1 or less, 1. 07 or less, 1.05 or less, 1.03 or less, or even 1.02 or less.
  • the ratio G7d / G24h is, for example, 1 or more.
  • the time T 0 at which the pressure-sensitive adhesive sheet is formed is the time at which the formation of the pressure-sensitive adhesive sheet is completed, and can be specifically determined according to the type of the pressure-sensitive adhesive composition (I).
  • the coating film containing the adhesive composition (I) coated on the base film is dried by heating, and then naturally cooled. It can be defined as the point of time when normal temperature is reached. Drying conditions (temperature and time) are, for example, 90° C. and 100 seconds. Normal temperature is 20-25°C. However, the time T 0 can be determined by the time when the temperature reaches 25°C.
  • the time T 0 can be defined as the time point at which the progress of photocuring is completed by irradiating the coating film containing the pressure-sensitive adhesive composition (I) with an active energy ray.
  • the photocurable coating film comprises a monomer (group) that becomes a (meth)acrylic polymer (A) by polymerization, a cross-linking agent (B), and, if necessary, a partial polymer of the monomer (group) , a polymerization initiator, an additive, a solvent, and the like.
  • the thickness of the coating film when determining the time T 0 is, for example, the thickness at which the thickness of the adhesive sheet formed is 50 ⁇ m.
  • the gel fraction at each time point can be evaluated as follows. First, about 0.2 g is scraped from the adhesive sheet for each time point to obtain a small piece. Next, the obtained small piece is wrapped with an expanded porous membrane of polytetrafluoroethylene (NTF1122 manufactured by Nitto Denko, average pore size 0.2 ⁇ m) and tied with a kite string to obtain a test piece. Next, the weight A of the obtained test piece is measured. Weight A is the sum of the weights of the adhesive sheet piece, the stretched porous membrane and the kite string. The total weight B of the stretched porous membrane and the kite string used is measured in advance.
  • NTF1122 polytetrafluoroethylene
  • the gel fractions G 0 , G 2h , G 24h and G 7d are determined, for example, by the glass transition temperature (Tg) and composition of the base polymer contained in the pressure-sensitive adhesive composition; It varies based on various factors such as the type and compounding amount of the agent; and the drying (curing) conditions for forming a pressure-sensitive adhesive sheet from the pressure-sensitive adhesive composition.
  • Tg glass transition temperature
  • composition of the base polymer contained in the pressure-sensitive adhesive composition It varies based on various factors such as the type and compounding amount of the agent; and the drying (curing) conditions for forming a pressure-sensitive adhesive sheet from the pressure-sensitive adhesive composition.
  • the (meth)acrylic polymer (A) preferably has, as a main unit, a structural unit derived from the (meth)acrylic monomer (A1) having an alkyl group having 1 to 30 carbon atoms in the side chain.
  • the alkyl group may be linear or branched.
  • the (meth)acrylic polymer (A) may have one or more structural units derived from the (meth)acrylic monomer (A1).
  • Examples of (meth) acrylic monomers (A1) include methyl (meth) acrylate, ethyl (meth) acrylate, n-butyl (meth) acrylate, s-butyl (meth) acrylate, t-butyl (meth) acrylate.
  • the term "main unit" refers to the total structural units of the poly
  • the (meth)acrylic polymer (A) may have structural units derived from the (meth)acrylic monomer (A1) having a long-chain alkyl group in its side chain.
  • An example of said monomer (A1) is n-dodecyl (meth)acrylate (lauryl (meth)acrylate).
  • the term "long-chain alkyl group” means an alkyl group having 6 to 30 carbon atoms.
  • the (meth)acrylic polymer (A) is a structural unit derived from the (meth)acrylic monomer (A1) having a glass transition temperature (Tg) in the range of ⁇ 70 to ⁇ 20° C. when homopolymerized. may have An example of said monomer (A1) is n-butyl acrylate.
  • the (meth)acrylic polymer (A) may have structural units other than the structural units derived from the (meth)acrylic monomer (A1).
  • the structural unit is derived from the monomer (A2) copolymerizable with the (meth)acrylic monomer (A1).
  • the (meth)acrylic polymer (A) may have one or more of these structural units.
  • the monomer (A2) is an aromatic ring-containing monomer.
  • the aromatic ring-containing monomer may be an aromatic ring-containing (meth)acrylic monomer.
  • aromatic ring-containing monomers include phenyl (meth) acrylate, phenoxyethyl (meth) acrylate, benzyl (meth) acrylate, phenoxydiethylene glycol (meth) acrylate, ethylene oxide-modified nonylphenol (meth) acrylate, hydroxyethylated ⁇ - naphthol (meth)acrylate and biphenyl (meth)acrylate.
  • the content of structural units derived from aromatic ring-containing monomers in the (meth)acrylic polymer (A) is, for example, 0 to 50% by weight, 1 to 30% by weight, 5 to 25% by weight, 8 to 20% by weight. % by weight, 10-18% by weight, or even 12-16% by weight.
  • a self-polymer of the cross-linking agent (B) may be formed.
  • Having a structural unit derived from an aromatic ring-containing monomer in the (meth)acrylic polymer (A) is a phase between the (meth)acrylic polymer (A), the cross-linking agent (B), and its self-polymer. improve solubility. Improved compatibility can contribute to improved uniformity of the pressure-sensitive adhesive sheet, for example, by suppressing precipitation of the self-polymer.
  • the hydroxyl group-containing monomer may be a hydroxyl group-containing (meth)acrylic monomer.
  • hydroxyl-containing monomers are 2-hydroxyethyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, 6-hydroxyhexyl (meth)acrylate, 8-hydroxyoctyl ( hydroxyalkyl (meth)acrylates such as meth)acrylates, 10-hydroxydecyl (meth)acrylate and 12-hydroxylauryl (meth)acrylate, and (4-hydroxymethylcyclohexyl)-methylacrylate.
  • the hydroxyl group can react with various cross-linking agents.
  • the content of structural units derived from hydroxyl group-containing monomers in the (meth)acrylic polymer (A) may be 1% by weight or less. It may be 5% by weight or less, further 0.1% by weight or less, or 0% by weight (without including the structural unit).
  • the monomer (A2) may be a carboxyl group-containing monomer, an amino group-containing monomer, or an amide group-containing monomer.
  • carboxyl group-containing monomers are (meth)acrylic acid, carboxyethyl (meth)acrylate, carboxypentyl (meth)acrylate, itaconic acid, maleic acid, fumaric acid and crotonic acid.
  • amino group-containing monomers are N,N-dimethylaminoethyl (meth)acrylate and N,N-dimethylaminopropyl (meth)acrylate.
  • amide group-containing monomers are (meth)acrylamide, N,N-dimethyl(meth)acrylamide, N,N-diethyl(meth)acrylamide, N-isopropylacrylamide, N-methyl(meth)acrylamide, N- Butyl (meth)acrylamide, N-hexyl (meth)acrylamide, N-methylol (meth)acrylamide, N-methylol-N-propane (meth)acrylamide, aminomethyl (meth)acrylamide, aminoethyl (meth)acrylamide, mercaptomethyl (Meth) acrylamide-based monomers such as mercaptoethyl (meth) acrylamide; and N-vinyl group-containing lactam monomers such as N-vinylpyrrolidone and N-vinyl- ⁇ -caprolactam.
  • the self-polymerizability of the cross-linking agent (B) can be enhanced. Improvement of the self-polymerization of the cross-linking agent (B) can contribute to suppression of peeling of the pressure-sensitive adhesive sheet in a humidified environment, and stabilization of physical properties of the pressure-sensitive adhesive sheet in a system having a high content of the cross-linking agent (B). .
  • the monomer (A2) may be a polyfunctional monomer.
  • multifunctional monomers are hexanediol di(meth)acrylate (1,6-hexanediol di(meth)acrylate), butanediol di(meth)acrylate, (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, trimethylolpropane tri( polyfunctional acrylates such as meth)acrylates, tetramethylolmethane tri(meth)acrylates, allyl (meth)acrylates, vinyl (meth)acrylates, epoxy acrylates, polyester acrylates and urethane acrylates; and divin
  • the total content of structural units derived from the carboxyl group-containing monomer, amino group-containing monomer, amide group-containing monomer and polyfunctional monomer in the (meth)acrylic polymer (A) is preferably is 20% by weight or less, more preferably 10% by weight or less, and still more preferably 8% by weight or less.
  • the total content is, for example, 0.01% by weight or more, and may be 0.05% by weight or more.
  • the (meth)acrylic polymer (A) may not contain structural units derived from polyfunctional monomers.
  • Examples of other monomers (A2) include 2-methoxyethyl (meth)acrylate, 2-ethoxyethyl (meth)acrylate, methoxytriethylene glycol (meth)acrylate, and 3-methoxy (meth)acrylate.
  • Alkoxyalkyl (meth)acrylates such as propyl, 3-ethoxypropyl (meth)acrylate, 4-methoxybutyl (meth)acrylate and 4-ethoxybutyl (meth)acrylate; glycidyl (meth)acrylate and ( Epoxy group-containing monomers such as methyl glycidyl acrylate; sulfonic acid group-containing monomers such as sodium vinyl sulfonate; phosphoric acid group-containing monomers; cyclopentyl (meth)acrylate, cyclohexyl (meth)acrylate and (meth)acrylic acid esters having an alicyclic hydrocarbon group such as isobornyl (meth)acrylate; vinyl esters such as vinyl acetate and vinyl propionate; aromatic vinyl compounds such as styrene and vinyltoluene; ethylene, propylene olefins, such as butadiene, isoprene and isobutylene, or die
  • the total content of structural units derived from the other monomer (A2) in the (meth)acrylic polymer (A) is, for example, 30% by weight or less, and may be 10% by weight or less, or 0 % by weight (not including the structural unit).
  • the (meth)acrylic polymer (A) can be formed by polymerizing one or more of the above monomers by a known method.
  • a monomer and a partial polymer of the monomer may be polymerized.
  • Polymerization can be carried out, for example, by solution polymerization, emulsion polymerization, bulk polymerization, thermal polymerization, or active energy ray polymerization. Solution polymerization and active energy ray polymerization are preferred because they can form a pressure-sensitive adhesive sheet with excellent optical transparency.
  • Polymerization is preferably carried out while avoiding contact of the monomer and/or partial polymer with oxygen. Polymerization in shutdown can be employed.
  • the (meth)acrylic polymer (A) to be formed may be in any form such as a random copolymer, a block copolymer, or a graft copolymer.
  • the polymerization system forming the (meth)acrylic polymer (A) may contain one or more polymerization initiators.
  • the type of polymerization initiator can be selected depending on the polymerization reaction, and may be, for example, a thermal polymerization initiator or a photopolymerization initiator.
  • Solvents used for solution polymerization include esters such as ethyl acetate and n-butyl acetate; aromatic hydrocarbons such as toluene and benzene; aliphatic hydrocarbons such as n-hexane and n-heptane; alicyclic hydrocarbons such as methylcyclohexane; and ketones such as methyl ethyl ketone and methyl isobutyl ketone.
  • the solvent is not limited to the above examples.
  • the solvent may be a mixed solvent of two or more solvents.
  • Polymerization initiators used for solution polymerization are, for example, azo polymerization initiators, peroxide polymerization initiators, and redox polymerization initiators.
  • Peroxide polymerization initiators are, for example, dibenzoyl peroxide and t-butyl permaleate.
  • the azo polymerization initiator disclosed in JP-A-2002-69411 is preferable.
  • the azo polymerization initiator for example, 2,2'-azobisisobutyronitrile (AIBN), 2,2'-azobis-2-methylbutyronitrile, 2,2'-azobis (2-methylpropion acid) dimethyl, 4,4'-azobis-4-cyanovaleric acid.
  • AIBN 2,2'-azobisisobutyronitrile
  • 2,2'-azobis-2-methylbutyronitrile 2,2'-azobis (2-methylpropion acid) dimethyl
  • 4,4'-azobis-4-cyanovaleric acid is not limited to the above examples.
  • the active energy rays used for active energy ray polymerization are, for example, ionizing radiation such as ⁇ -rays, ⁇ -rays, ⁇ -rays, neutron beams and electron beams, and ultraviolet rays.
  • the active energy rays are preferably ultraviolet rays.
  • Polymerization by irradiation with ultraviolet rays is also called photopolymerization.
  • a polymerization system for active energy ray polymerization typically contains a photopolymerization initiator. Polymerization conditions for active energy polymerization are not limited as long as the (meth)acrylic polymer (A) is formed.
  • Photopolymerization initiators include, for example, benzoin ether-based photopolymerization initiators, acetophenone-based photopolymerization initiators, ⁇ -ketol-based photopolymerization initiators, aromatic sulfonyl chloride-based photopolymerization initiators, and photoactive oxime-based photopolymerization initiators. , a benzoin-based photopolymerization initiator, a benzyl-based photopolymerization initiator, a benzophenone-based photopolymerization initiator, a ketal-based photopolymerization initiator, and a thioxanthone-based photopolymerization initiator.
  • the photopolymerization initiator is not limited to the above examples.
  • Benzoin ether-based photopolymerization initiators include, for example, benzoin methyl ether, benzoin ethyl ether, benzoin propyl ether, benzoin isopropyl ether, benzoin isobutyl ether, 2,2-dimethoxy-1,2-diphenylethan-1-one, anisolemethyl is ether.
  • Acetophenone-based photopolymerization initiators include, for example, 2,2-diethoxyacetophenone, 2,2-dimethoxy-2-phenylacetophenone, 1-hydroxycyclohexylphenylketone, 4-phenoxydichloroacetophenone, 4-(t-butyl)dichloro Acetophenone.
  • Examples of ⁇ -ketol photopolymerization initiators are 2-methyl-2-hydroxypropiophenone and 1-[4-(2-hydroxyethyl)phenyl]-2-methylpropan-1-one.
  • the aromatic sulfonyl chloride photopolymerization initiator is, for example, 2-naphthalenesulfonyl chloride.
  • a photoactive oxime-based photopolymerization initiator is, for example, 1-phenyl-1,1-propanedione-2-(o-ethoxycarbonyl)-oxime.
  • a benzoin-based photopolymerization initiator is, for example, benzoin.
  • a benzylic photopolymerization initiator is, for example, benzyl.
  • benzophenone-based photopolymerization initiators examples include benzophenone, benzoylbenzoic acid, 3,3'-dimethyl-4-methoxybenzophenone, polyvinylbenzophenone, and ⁇ -hydroxycyclohexylphenyl ketone.
  • a ketal photopolymerization initiator is, for example, benzyl dimethyl ketal.
  • Thioxanthone-based photopolymerization initiators are, for example, thioxanthone, 2-chlorothioxanthone, 2-methylthioxanthone, 2,4-dimethylthioxanthone, isopropylthioxanthone, 2,4-diisopropylthioxanthone, and dodecylthioxanthone.
  • the amount of the photopolymerization initiator used is, for example, 0.01 to 1 part by weight, and may be 0.05 to 0.5 part by weight, based on 100 parts by weight of the total amount of the monomers.
  • the weight average molecular weight (Mw) of the (meth)acrylic polymer (A) is, for example, 1,000,000 to 2,800,000, and from the viewpoint of the durability and heat resistance of the pressure-sensitive adhesive sheet, it is 1,200,000 or more, further 1,400,000 or more. may be
  • the weight average molecular weight (Mw) of polymers and oligomers in this specification is a value (converted to polystyrene) based on GPC (gel permeation chromatography) measurement.
  • the content of the (meth)acrylic polymer (A) in the pressure-sensitive adhesive composition (I) is, for example, 50% by weight or more, 60% by weight or more, 70% by weight or more, and further 80% by weight in terms of solid content. or more.
  • the upper limit of the content is, for example, 99% by weight or less, and may be 97% by weight or less, 95% by weight or less, 93% by weight or less, or even 90% by weight or less.
  • Cross-linking agent (B) is typically a polyfunctional cross-linking agent having two or more cross-linking reactive groups per molecule.
  • the cross-linking agent (B) may be a tri- or higher functional cross-linking agent having 3 or more cross-linking reactive groups per molecule.
  • the upper limit of the number of cross-linking reactive groups per molecule is 5, for example.
  • the cross-linking agent (B) is, for example, an isocyanate-based cross-linking agent.
  • the isocyanate-based cross-linking agent contains an isocyanate group as a cross-linking reactive group.
  • the isocyanate-based cross-linking agent (B) may be an aromatic isocyanate compound, an alicyclic isocyanate compound, or an aliphatic isocyanate compound.
  • aromatic isocyanate compounds that can be used for the cross-linking agent (B) include phenylene diisocyanate, 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, 2,2′-diphenylmethane diisocyanate, and 4,4′-diphenylmethane. diisocyanate, 4,4'-toluidine diisocyanate, 4,4'-diphenyl ether diisocyanate, 4,4'-diphenyl diisocyanate and 1,5-naphthalene diisocyanate, xylylene diisocyanate.
  • alicyclic isocyanate compounds that can be used for the cross-linking agent (B) include 1,3-cyclopentene diisocyanate, 1,3-cyclohexane diisocyanate, 1,4-cyclohexane diisocyanate, isophorone diisocyanate, hydrogenated diphenylmethane diisocyanate, hydrogenated xyloxy diisocyanate, hydrogenated tolylene diisocyanate and hydrogenated tetramethylxylylene diisocyanate.
  • aliphatic isocyanate compounds that can be used as the cross-linking agent (B) include trimethylene diisocyanate, tetramethylene diisocyanate, hexamethylene diisocyanate, pentamethylene diisocyanate, 1,2-propylene diisocyanate, 1,3-butylene diisocyanate, and dodecamethylene diisocyanate. and 2,4,4-trimethylhexamethylene diisocyanate.
  • the cross-linking agent (B) may be a derivative of the above isocyanate compound.
  • derivatives include multimers (dimers, trimers, pentamers, etc.), adducts (adducts) obtained by adding polyhydric alcohols such as trimethylolpropane, urea modified products, and biuret modified products. , allophanate-modified, isocyanurate-modified, carbodiimide-modified, and urethane prepolymers obtained by addition to polyether polyol, polyester polyol, acrylic polyol, polybutadiene polyol, polyisoprene polyol, and the like.
  • the cross-linking agent (B) is preferably an aromatic isocyanate compound and its derivatives, more preferably tolylene diisocyanate and its derivatives (in other words, tolylene diisocyanate-based (TDI-based) cross-linking agent).
  • TDI-based cross-linking agents are superior to xylylene diisocyanate and its derivatives (in other words, xylylene diisocyanate-based (XDI-based) cross-linking agents) in terms of reaction uniformity.
  • TDI-based cross-linking agent is an adduct of tolylene diisocyanate and a polyfunctional alcohol, and a more specific example is a trimethylolpropane/tolylene diisocyanate trimer adduct.
  • a commercially available product can be used for the cross-linking agent (B).
  • Examples of commercially available products include Millionate MT, Millionate MTL, Millionate MR-200, Millionate MR-400, Coronate L, Coronate HL and Coronate HX (manufactured by Tosoh; all trade names), Takenate D-102 and Takenate D. -103, Takenate D-110N, Takenate D-120N, Takenate D-140N, Takenate D-160N, Takenate D-165N, Takenate D-170HN, Takenate D-178N, Takenate 500 and Takenate 600 (manufactured by Mitsui Chemicals; Both are trade names).
  • Coronate L Takenate D-102 and Takenate D-103 (all of which are trimethylolpropane/tolylene diisocyanate trimer adducts) can be preferably used.
  • the amount of the cross-linking agent (B) in the adhesive composition (I) is, for example, 5 parts by weight or more, 6 parts by weight or more, and 7 parts by weight with respect to 100 parts by weight of the (meth)acrylic polymer (A). Above, it may be 8 parts by weight or more, 9 parts by weight or more, 10 parts by weight or more, more than 10 parts by weight, or even 11 parts by weight or more.
  • the upper limit of the compounding amount is, for example, 30 parts by weight or less, 28 parts by weight or less, 25 parts by weight or less, 23 parts by weight or less, 20 parts by weight or less, 19 parts by weight or less, 18 parts by weight or less, and further 15 parts by weight or less. may be
  • the pressure-sensitive adhesive composition (I) having a blending amount within the above range is suitable for forming a pressure-sensitive adhesive sheet having an increased elastic modulus.
  • the cross-linking agent (B) reacts with each other during the formation of the pressure-sensitive adhesive sheet, facilitating the formation of a self-polymer of the cross-linking agent (B).
  • the formation of the self-polymer increases the cohesive force of the adhesive sheet, thereby contributing to the formation of the adhesive sheet that can suppress the dimensional change of the optical film.
  • precipitation of the self-polymer in the formed pressure-sensitive adhesive sheet is suppressed, thereby improving the uniformity of the pressure-sensitive adhesive sheet.
  • the pressure-sensitive adhesive sheet formed from the pressure-sensitive adhesive composition (I) has an interpenetrating network (IPN) structure of a cross-linked product of the (meth)acrylic polymer (A) and a self-polymer of the cross-linking agent (B).
  • IPN interpenetrating network
  • the IPN structure is suitable for improving the durability of the adhesive sheet.
  • cross-linking agents (B) are peroxide-based cross-linking agents, epoxy-based cross-linking agents, imine-based cross-linking agents and polyfunctional metal chelates.
  • the cross-linking agent (B) is preferably isocyanate-based.
  • the total amount is 0.1 to 5 parts by weight with respect to 100 parts by weight of the (meth)acrylic polymer (A). parts are preferred, and 0.1 to 3 parts by weight, 0.1 to 2 parts by weight and 0.1 to 1 part by weight, in that order, are more preferred.
  • the pressure-sensitive adhesive composition (I) may not contain a cross-linking agent (B) other than an isocyanate-based cross-linking agent, such as an epoxy-based cross-linking agent.
  • the pressure-sensitive adhesive composition (I) may further contain a (meth)acrylic oligomer (D).
  • the (meth)acrylic oligomer (D) can have the same composition as the (meth)acrylic polymer (A) described above, except that the weight average molecular weight (Mw) is different.
  • the weight average molecular weight (Mw) of the (meth)acrylic oligomer (D) is, for example, 1000 or more, and may be 2000 or more, 3000 or more, or even 4000 or more.
  • the upper limit of the weight average molecular weight (Mw) of the (meth)acrylic oligomer is, for example, 30,000 or less, and may be 15,000 or less, 10,000 or less, or even 7,000 or less.
  • the (meth)acrylic oligomer (D) has, for example, one or more structural units derived from the following monomers: methyl (meth)acrylate, ethyl (meth)acrylate, propyl ( meth) acrylate, isopropyl (meth) acrylate, butyl (meth) acrylate, isobutyl (meth) acrylate, s-butyl (meth) acrylate, t-butyl (meth) acrylate, pentyl (meth) acrylate, isopentyl (meth) acrylate, hexyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, heptyl (meth)acrylate, octyl (meth)acrylate, isooctyl (meth)acrylate, nonyl (meth)acrylate, isononyl (meth)acrylate, decyl (meth)acrylate,
  • the (meth)acrylic oligomer (D) preferably has structural units derived from a (meth)acrylic monomer having a relatively bulky structure.
  • the adhesiveness of the adhesive sheet can be further enhanced.
  • the acrylic monomer include alkyl (meth)acrylates having a branched alkyl group such as isobutyl (meth)acrylate and t-butyl (meth)acrylate; cyclohexyl (meth)acrylate and isobornyl (meth)acrylate.
  • the monomer preferably has a cyclic structure, more preferably two or more cyclic structures.
  • the (meth)acrylic oligomer (D) is polymerized and/or the pressure-sensitive adhesive sheet is formed when UV irradiation is performed, the progress of polymerization and/or formation is hardly inhibited. It preferably does not have an unsaturated bond, and for example, an alkyl (meth)acrylate having an alkyl group with a branched structure, or an ester of (meth)acrylic acid and an alicyclic alcohol can be used.
  • the (meth)acrylic oligomer (D) include a copolymer of butyl acrylate, methyl acrylate and acrylic acid, a copolymer of cyclohexyl methacrylate and isobutyl methacrylate, and a copolymer of cyclohexyl methacrylate and isobornyl methacrylate.
  • Copolymers of cyclohexyl methacrylate and acryloylmorpholine Copolymers of cyclohexyl methacrylate and diethylacrylamide, copolymers of 1-adamantyl acrylate and methyl methacrylate, copolymers of dicyclopentanyl methacrylate and isobornyl methacrylate.
  • Polymer copolymer of methyl methacrylate and at least one selected from dicyclopentanyl methacrylate, cyclohexyl methacrylate, isobornyl methacrylate, isobornyl acrylate and cyclopentanyl methacrylate, homopolymer of dicyclopentanyl acrylate , a homopolymer of 1-adamantyl methacrylate and a homopolymer of 1-adamantyl acrylate.
  • the polymerization method for the (meth)acrylic polymer (A) described above can be employed for the polymerization of the (meth)acrylic oligomer (D).
  • the amount thereof is, for example, 70 parts by weight or less with respect to 100 parts by weight of the (meth)acrylic polymer (A), It may be 50 parts by weight or less, or even 40 parts by weight or less.
  • the lower limit of the amount to be blended is, for example, 1 part by weight or more, 2 parts by weight or more, and may be 3 parts by weight or more with respect to 100 parts by weight of the (meth)acrylic polymer (A).
  • the pressure-sensitive adhesive composition (I) may not contain the (meth)acrylic oligomer (D).
  • the pressure-sensitive adhesive composition (I) may contain other additives.
  • additives include silane coupling agents, polyfunctional alcohols, colorants such as pigments and dyes, surfactants, plasticizers, tackifiers, surface lubricants, leveling agents, rework improvers, softeners, oxidation Anti-aging agents, anti-aging agents, light stabilizers, ultraviolet absorbers, polymerization inhibitors, anti-static agents (ionic compounds such as alkali metal salts, ionic liquids, ionic solids, etc.), inorganic fillers, organic fillers, metal powders and other powders, particles, and foil-like materials.
  • the additive can be blended in an amount of, for example, 10 parts by weight or less, preferably 5 parts by weight or less, and more preferably 1 part by weight or less per 100 parts by weight of the (meth)acrylic polymer (A).
  • silane coupling agents are 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropyltriethoxysilane, 3-glycidoxypropylmethyldiethoxysilane and 2-(3,4-epoxycyclohexyl)ethyl Epoxy group-containing silane coupling agents such as trimethoxysilane; 3-aminopropyltrimethoxysilane, N-2-(aminoethyl)-3-aminopropylmethyldimethoxysilane, 3-triethoxysilyl-N-(1,3 -dimethylbutylidene)propylamine and amino group-containing silane coupling agents such as N-phenyl- ⁇ -aminopropyltrimethoxysilane; ) acrylic group-containing silane coupling agents; and isocyanate group-containing silane coupling agents such as 3-isocyanatopropyltriethoxysilane.
  • the amount is, for example, 5 parts by weight or less, 3 parts by weight or less, relative to 100 parts by weight of the (meth)acrylic polymer (A), It may be 1 part by weight or less, 0.5 parts by weight or less, 0.2 parts by weight or less, 0.1 parts by weight or less, or even 0.05 parts by weight or less.
  • the adhesive composition (I) may not contain a silane coupling agent.
  • the adhesive composition (I) may contain a polyfunctional alcohol.
  • the molecular weight of the polyfunctional alcohol is, for example, 240 or less, and may be 230 or less, 220 or less, 210 or less, 200 or less, 190 or less, 180 or less, 170 or less, 160 or less, or even 150 or less.
  • the lower limit of the molecular weight is, for example, 60 or more, and may be 80 or more, 90 or more, or even 100 or more.
  • polyfunctional alcohols are alkylene glycols such as ethylene glycol and propylene glycol and their polymers; ether glycols such as diethylene glycol and their polymers; trimethylolethane; trimethylolpropane; is.
  • Polyfunctional alcohols are preferably trimethylolpropane, glycerin, and diethylene glycol and polymers thereof, more preferably trimethylolpropane.
  • the polyfunctional alcohol may be trifunctional or higher.
  • trifunctional polyfunctional alcohols are trimethylolpropane and glycerin.
  • the polyfunctional alcohol does not have to have a reactive group with reactivity with the cross-linking agent (B) other than the hydroxyl group.
  • the reactive group is, for example, at least one selected from an amino group, a carboxyl group and an epoxy group, particularly an amino group.
  • the blending amount of the polyfunctional alcohol in the adhesive composition (I) is, for example, 0.5 parts by weight or more and 20 parts by weight or less with respect to 100 parts by weight of the (meth)acrylic polymer (A).
  • the upper limit of the blending amount may be 15 parts by weight or less, 10 parts by weight or less, 8 parts by weight or less, 5 parts by weight or less, 4 parts by weight or less, or even 3 parts by weight or less.
  • the adhesive composition (I) may not contain a cross-linking accelerator such as a catalyst.
  • cross-linking accelerators are polyethers, polyether polyols, and phosphate esters having reactive groups reactive with the cross-linking agent (B).
  • the reactive group is, for example, at least one selected from a hydroxyl group, an amino group, a carboxyl group and an epoxy group, particularly a hydroxyl group or an amino group.
  • the pressure-sensitive adhesive composition (I) may not contain polyether polyols having amino groups, and may not contain phosphate esters having hydroxyl groups.
  • Types of the pressure-sensitive adhesive composition (I) are, for example, emulsion type, solvent type (solution type), active energy ray-curable type (light-curing type), and heat-melting type (hot-melt type).
  • the pressure-sensitive adhesive composition (I) may be solvent-based from the viewpoint of forming a pressure-sensitive adhesive sheet with superior durability.
  • the solvent-based pressure-sensitive adhesive composition (I) may not contain a photocuring agent such as an ultraviolet curing agent.
  • the pressure-sensitive adhesive sheet 1 in FIG. 1 is formed from the pressure-sensitive adhesive composition (I).
  • the adhesive sheet 1 contains, for example, a crosslinked product of (meth)acrylic polymer (A).
  • the adhesive sheet 1 can be formed from the adhesive composition (I) as follows.
  • the pressure-sensitive adhesive composition (I) or a mixture of the pressure-sensitive adhesive composition (I) and a solvent is applied to a base film to form a coating film, and the formed coating film is dried. An adhesive sheet 1 is formed.
  • the pressure-sensitive adhesive composition (I) is thermally cured by heat during drying.
  • the active energy ray-curable type for example, a monomer (group) that becomes a (meth)acrylic polymer (A) by polymerization, a cross-linking agent (B), and, if necessary, a monomer A mixture of the partial polymer (group), polymerization initiator, oligomer (D), additive, solvent, etc.
  • the base film is applied to a base film and irradiated with active energy rays to form a pressure-sensitive adhesive sheet 1 .
  • the solvent may be removed by drying before irradiation with active energy rays.
  • the base film may be a film (release film) whose coating surface has been subjected to release treatment.
  • the adhesive sheet 1 formed on the base film can be transferred to any layer.
  • the base film may be an optical film, and in this case, an optical laminate including the adhesive sheet 1 and the optical film is obtained.
  • Coating is, for example, 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, extrusion coating using a die coater, or the like. can be implemented by
  • the drying temperature after coating is, for example, 40 to 200°C.
  • the drying temperature may be 160° C. or lower, 150° C. or lower, 130° C. or lower, 120° C. or lower, or even 100° C. or lower.
  • the adhesive sheet 1 having excellent durability can be obtained.
  • the adhesive sheet 1 may be obtained by drying the coating film of the adhesive composition (I) at a temperature of 130° C. or lower, 120° C. or lower, or further 100° C. or lower.
  • the drying time is, for example, 5 seconds to 20 minutes, and may be 5 seconds to 10 minutes, or even 10 seconds to 5 minutes.
  • the drying temperature and drying time when drying after coating may be within the above ranges.
  • composition and mixture to be applied to the base film preferably have a viscosity suitable for handling and coating. Therefore, for the active energy ray-curable type, the mixture to be applied preferably contains a partial polymer of the monomer (group).
  • the coated surface is subjected to release treatment with a silicone compound.
  • the thickness of the adhesive sheet 1 is, for example, 1 to 200 ⁇ m, 5 to 150 ⁇ m, and may be 10 to 100 ⁇ m.
  • the storage elastic modulus G′ (25° C.) of the adhesive sheet 1 is, for example, 0.15 MPa or higher, 0.2 MPa or higher, 0.25 MPa or higher, 0.3 MPa or higher, 0.4 MPa or higher, 0.5 MPa or higher, 0.5 MPa or higher, and 0.2 MPa or higher. It may be 6 MPa or more, 0.7 MPa or more, 0.8 MPa or more, 0.9 MPa or more, 1.0 MPa or more, or even 1.1 MPa or more.
  • the upper limit of the storage modulus G' (25°C) is, for example, 5 MPa or less, and may be 3.0 MPa or less, 2.5 MPa or less, or even 2.0 MPa or less.
  • the pressure-sensitive adhesive sheet 1 having a storage elastic modulus G' within the above range is more suitable for suppressing changes in the dimensions of the optical film.
  • the storage elastic modulus (25° C.) of PSA Sheet 1 can be evaluated by the following method. First, a sample for measurement made of the material constituting the adhesive sheet 1 is prepared. The shape of the measurement sample is disc-shaped. The measurement sample has a bottom diameter of 8 mm and a thickness of 2 mm. A sample for measurement may be obtained by punching a disc-shaped laminate from a laminate in which a plurality of pressure-sensitive adhesive sheets 1 are laminated. Next, a dynamic viscoelasticity measurement is performed on the measurement sample. For dynamic viscoelasticity measurement, for example, ARES-G2 manufactured by TA Instruments can be used. From the results of the dynamic viscoelasticity measurement, the storage elastic modulus G' of the pressure-sensitive adhesive sheet 1 at 25°C can be specified. The conditions for the dynamic viscoelasticity measurement are as follows. ⁇ Measurement conditions Frequency: 1Hz Deformation mode: Torsion Measurement temperature: -70°C to 150°C Heating rate: 5°C/min
  • the adhesive sheet 1 can be used for optical applications, for example.
  • the pressure-sensitive adhesive sheet 1 may be used for optical laminates and/or image display devices.
  • the pressure-sensitive adhesive sheet 1 is suitable for use in image display devices, such as an image display device with a narrow frame and an image display device with a relatively large screen size, for which suppression of dimensional change in the optical film is particularly required. .
  • image display devices such as an image display device with a narrow frame and an image display device with a relatively large screen size, for which suppression of dimensional change in the optical film is particularly required.
  • optical laminate An example of the optical laminate of this embodiment is shown in FIG.
  • the optical layered body 10A of FIG. 2 includes an adhesive sheet 1 and an optical film 2. As shown in FIG. The adhesive sheet 1 and the optical film 2 are laminated together. 10 A of optical laminated bodies can be used as an optical film with an adhesive sheet.
  • optical film 2 examples are a polarizing plate, a retardation film, and a laminated film containing a polarizing plate and/or a retardation film.
  • the optical film 2 is not limited to the above examples.
  • the optical film 2 may contain a film made of glass.
  • a polarizing plate includes a polarizer.
  • a polarizer protective film may be bonded to at least one surface of the polarizer. Any pressure-sensitive adhesive or adhesive can be used for joining the polarizer and the polarizer protective film.
  • the adhesive sheet 1 may be used for bonding.
  • a polarizer is typically a polyvinyl alcohol (PVA) film in which iodine is oriented by stretching such as stretching in air (dry stretching) or stretching in boric acid solution.
  • PVA polyvinyl alcohol
  • a retardation film is a film that has birefringence in the in-plane direction and/or the thickness direction.
  • a retardation film is, for example, a stretched resin film or a film in which a liquid crystal material is oriented and fixed.
  • the retardation film includes a ⁇ / 4 plate, a ⁇ / 2 plate, an antireflection retardation film (see, for example, paragraphs 0221, 0222, 0228 of JP-A-2012-133303), a viewing angle compensation retardation film (for example, JP-A-2012-133303, paragraphs 0225 and 0226), obliquely oriented retardation film for viewing angle compensation (eg, JP-A-2012-13303, paragraph 0227).
  • the retardation film is not limited to the above examples as long as it has birefringence in the in-plane direction and/or the thickness direction.
  • the retardation value of the retardation film, the arrangement angle, the three-dimensional birefringence, whether it is a single layer or a multilayer, and the like are not limited.
  • a known film can be used as the retardation film.
  • the thickness of the optical film 2 is, for example, 1 to 200 ⁇ m.
  • the thickness of the optical film 2, which is a polarizing plate, is, for example, 1 to 150 ⁇ m, and may be 100 ⁇ m or less, 75 ⁇ m or less, 50 ⁇ m or less, 20 ⁇ m or less, or even 15 ⁇ m or less.
  • the lower limit of the thickness may be 10 ⁇ m or more, 20 ⁇ m or more, 50 ⁇ m or more, 75 ⁇ m or more, or even 100 ⁇ m or more.
  • the optical film 2 may be a single layer or a laminated film composed of two or more layers.
  • the adhesive sheet 1 may be used for joining the layers.
  • FIG. 3 Another example of the optical laminate of this embodiment is shown in FIG.
  • the optical layered body 10B of FIG. 3 has a layered structure in which a release liner 3, an adhesive sheet 1 and an optical film 2 are layered in this order. By peeling off the release liner 3, the optical laminate 10B can be used as an optical film with an adhesive sheet.
  • the release liner 3 is typically a resin film.
  • resins that make up the release liner 3 are polyesters such as polyethylene terephthalate (PET), polyolefins such as polyethylene and polypropylene, polycarbonates, acrylics, polystyrenes, polyamides, and polyimides.
  • PET polyethylene terephthalate
  • the surface of the release liner 3 that contacts the adhesive sheet 1 may be subjected to a release treatment.
  • the release treatment is, for example, treatment with a silicone compound.
  • the release liner 3 is not limited to the above example.
  • the release liner 3 is peeled off when the optical layered body 10B is used, for example, when attached to the image forming layer.
  • the optical laminate 10C of FIG. 4 has a laminate structure in which a release liner 3, an adhesive sheet 1, a retardation film 2A, an interlayer adhesive 4 and a polarizing plate 2B are laminated in this order. After peeling off the release liner 3, the optical layered body 10C can be used by attaching it to, for example, an image forming layer.
  • a known adhesive can be used for the interlayer adhesive 4 .
  • the adhesive sheet 1 may be used as the interlayer adhesive 4 .
  • the optical laminate 10D of FIG. 5 has a laminate structure in which a release liner 3, an adhesive sheet 1, a retardation film 2A, an interlayer adhesive 4, a polarizing plate 2B and a protective film 5 are laminated in this order. After peeling off the release liner, the optical layered body 10D can be used, for example, by attaching it to the image forming layer.
  • the protective film 5 has a function of protecting the outermost optical film 2 (polarizing plate 2B) during distribution and storage of the optical layered body 10D and when the optical layered body 10D is incorporated in an image display device. Moreover, it may be the protective film 5 that functions as a window to an external space when incorporated in the image display device.
  • Protective film 5 is typically a resin film.
  • the resin constituting the protective film 5 is, for example, polyester such as PET, polyolefin such as polyethylene and polypropylene, acrylic, cycloolefin, polyimide, and polyamide, preferably polyester.
  • the protective film 5 is not limited to the above examples.
  • the protective film 5 may be a glass film or a laminated film containing a glass film.
  • the protective film 5 may be subjected to surface treatments such as antiglare, antireflection, and antistatic.
  • the protective film 5 may be bonded to the optical film 2 with any adhesive. Bonding with the adhesive sheet 1 is also possible.
  • the optical layered body of the present embodiment can be distributed and stored, for example, as a wound body in which a strip-shaped optical layered body is wound, or as a sheet-shaped optical layered body.
  • the optical laminate of this embodiment is typically used in an image display device.
  • the image display device is, for example, an EL display such as a liquid crystal display, an organic EL display and an inorganic EL display.
  • the image display device 11 in FIG. 6 includes a substrate 7, an image forming layer (for example, an organic EL layer or a liquid crystal layer) 6, an adhesive sheet 1, a retardation film 2A, an interlayer adhesive 4, a polarizing plate 2B and a protective film 5 in this order. It has a laminated structure.
  • the image display device 11 has the optical laminates 10A, 10B, 10C, and 10D of FIGS. 2 to 5 (excluding the release liner 3).
  • the substrate 7 and the image forming layer 6 may have the same configurations as those of the substrate and the image forming layer provided in a known image display device.
  • the image display device 11 in FIG. 6 may be an organic EL display or a liquid crystal display. However, the image display device 11 is not limited to this example.
  • the image display device 11 may be an electroluminescence (EL) display, a plasma display (PD), a field emission display (FED: Field Emission Display), or the like.
  • EL electroluminescence
  • PD plasma display
  • FED Field Emission Display
  • the image display device 11 may be used for home appliance use, vehicle use, public information display (PID) use, and the like.
  • the image display device of this embodiment can have any configuration as long as it includes the optical layered body of this embodiment.
  • the atmosphere for natural cooling after drying and for leaving the PSA sheet after time T 0 was 25° C. and 50% RH. It was confirmed by measuring the surface temperature of the film with an infrared radiation thermometer that the temperature of the coated film after drying returned to normal temperature due to natural cooling (in other words, the film was ready for use as an adhesive sheet). . Evaluation of the gel fraction G 0 was performed on the pressure-sensitive adhesive sheet 5 minutes after the time T 0 .
  • the storage elastic modulus G' (25°C) of the pressure-sensitive adhesive sheet was evaluated by the method described above. However, the sample for measurement was prepared by punching out a laminate obtained by stacking the produced pressure-sensitive adhesive sheets (7 days or more after time T 0 ) into a disc shape. ARES-G2 manufactured by TA Instruments was used for the dynamic viscoelasticity measurement of the measurement sample.
  • Humidification durability (corresponding to an accelerated durability test) of the PSA sheet was evaluated by the following method. First, a pressure-sensitive adhesive sheet-attached circularly polarizing plate having one exposed surface provided with each pressure-sensitive adhesive sheet produced in Examples and Comparative Examples (7 days or more after time T 0 ) was formed. Next, a circularly polarizing plate was fixed to the surface of a glass plate (Eagle XG manufactured by Corning) via the adhesive sheet. Fixing of the circularly polarizing plate was performed in an atmosphere of 23° C. and 50% RH. Next, after treatment in an autoclave at 50 ° C.
  • polarizing plate P1> (Production of polarizer) A long polyvinyl alcohol (PVA) resin film (manufactured by Kuraray, product name “PE3000”, thickness 30 ⁇ m) is uniaxially stretched in the longitudinal direction using a roll stretching machine (total stretching ratio 5.9 times) at the same time. , swelling, dyeing, cross-linking, washing and drying were sequentially performed on the resin film to prepare a polarizer having a thickness of 12 ⁇ m. In the swelling treatment, the resin film was stretched 2.2 times while being treated with pure water at 20°C.
  • PVA polyvinyl alcohol
  • the resin film was stretched 1.4 times while being treated with an aqueous solution containing iodine and potassium iodide at a weight ratio of 1:7 at 30°C.
  • the iodine concentration in the aqueous solution was adjusted so that the single transmittance of the polarizer to be produced was 45.0%.
  • a two-step process was employed for the cross-linking treatment.
  • the resin film was stretched 1.2 times while being treated with an aqueous solution of boric acid and potassium iodide at 40°C.
  • the content of boric acid in the aqueous solution used for the first-stage cross-linking treatment was 5.0% by weight, and the content of potassium iodide was 3.0% by weight.
  • the resin film was stretched 1.6 times while being treated with an aqueous solution of boric acid and potassium iodide at 65°C.
  • the content of boric acid in the aqueous solution used in the second-stage cross-linking treatment was 4.3% by weight, and the content of potassium iodide was 5.0% by weight.
  • a potassium iodide aqueous solution at 20° C. was used for the cleaning treatment.
  • the content of potassium iodide in the aqueous solution used for the cleaning treatment was 2.6% by weight.
  • the drying treatment was performed under drying conditions of 70° C. and 5 minutes.
  • polarizing plate P1 Preparation of polarizing plate P1
  • TAC triacetyl cellulose
  • KC2UA product name “KC2UA”, thickness 25 ⁇ m
  • a hard coat 7 ⁇ m thick
  • ⁇ Preparation of retardation film R1> (Preparation of first retardation film) Isosorbide (ISB) 26.2 parts by weight, 9,9-[4-(2-hydroxyethoxy)phenyl]fluorene (BHEPF) 100.5 parts by weight, 1,4-cyclohexanedimethanol (1,4-CHDM) 10 .7 parts by weight, 105.1 parts by weight of diphenyl carbonate (DPC), and 0.591 parts by weight of cesium carbonate (0.2% by weight aqueous solution) as a catalyst were charged into a reaction vessel and dissolved under a nitrogen atmosphere ( about 15 minutes). At this time, the temperature of the heat medium in the reaction vessel was set at 150° C., and stirring was carried out as necessary.
  • the pressure inside the reaction vessel was reduced to 13.3 kPa, and the temperature of the heat medium was raised to 190° C. in 1 hour. Phenol generated as the temperature of the heat medium increased was discharged out of the reaction vessel (the same applies hereinafter).
  • the pressure in the reaction vessel was changed to 6.67 kPa, and the temperature of the heat medium was raised to 230° C. in 15 minutes.
  • the stirring torque of the stirrer provided in the reaction vessel increased, the temperature of the heat medium was raised to 250° C. in 8 minutes, and the pressure in the reaction vessel was reduced to 0.200 kPa or less.
  • a single screw extruder manufactured by Isuzu Kakoki, screw diameter 25 mm, cylinder set temperature 220 ° C.), T die (width 200 mm, set temperature 220 ° C.), chill roll A long resin film having a thickness of 120 ⁇ m was obtained using a film forming apparatus equipped with a set temperature of 120 to 130° C. and a winder. Next, the obtained resin film was stretched in the width direction with a tenter stretching machine at a stretching temperature of 137 to 139° C. and a stretching ratio of 2.5 times to obtain a first retardation film.
  • a side chain type liquid crystal polymer (weight average molecular weight 5000) represented by the following chemical formula (I) (where 65 and 35 are mol% of each structural unit), a polymerizable liquid crystal exhibiting a nematic liquid crystal phase (manufactured by BASF) , trade name “Paliocolor LC242”) 80 parts by weight, and a photopolymerization initiator (manufactured by Ciba Specialty Chemicals, trade name “Irgacure 907”) 5 parts by weight are dissolved in 200 parts by weight of cyclopentanone to form a liquid crystal coating liquid.
  • a side chain type liquid crystal polymer (weight average molecular weight 5000) represented by the following chemical formula (I) (where 65 and 35 are mol% of each structural unit)
  • a polymerizable liquid crystal exhibiting a nematic liquid crystal phase manufactured by BASF
  • Paliocolor LC242 trade name “Paliocolor LC242”
  • a norbornene-based resin film manufactured by Nippon Zeon, trade name “Zeonex”
  • Zeonex which is a base film
  • the coating film was cured by irradiation with ultraviolet rays to form a liquid crystal solidified layer (thickness: 0.58 ⁇ m) as a second retardation film on the substrate film.
  • the polymerization reaction was allowed to proceed for 7 hours while maintaining the liquid temperature in the flask around 55°C.
  • ethyl acetate was added to the resulting reaction solution to adjust the solid content concentration to 30% by weight to obtain a solution of a (meth)acrylic polymer used as an interlaminar pressure-sensitive adhesive.
  • the weight average molecular weight of the obtained polymer was 2,200,000.
  • trimethylolpropane/tolylene diisocyanate trimer adduct manufactured by Tosoh, trade name "Coronate L" is added to 100 parts by weight of the solid content of the solution.
  • the pressure-sensitive adhesive composition PSA1 prepared above is applied to the release surface of a polyethylene terephthalate (PET) film (manufactured by Mitsubishi Chemical Polyester Film Co., Ltd., MRF38) having a thickness of 38 ⁇ m, which is a release film having a silicone-treated release surface. It was coated so that the thickness of the layer after drying was 12 ⁇ m, and dried at 155° C. for 1 minute to form an interlayer pressure-sensitive adhesive layer. Next, the formed interlayer pressure-sensitive adhesive layer was transferred to the protective layer (no hard coat) side of the polarizing plate P1 to obtain a polarizing plate with an interlayer pressure-sensitive adhesive layer.
  • PET polyethylene terephthalate
  • MRF38 silicone-treated release surface
  • each pressure-sensitive adhesive sheet prepared in Examples and Comparative Examples (7 days or more after time T 0 ) was transferred from the release film and pasted.
  • the polarizing plate with an interlayer pressure-sensitive adhesive layer prepared above was attached to the first retardation film side of the retardation film R1 via the interlayer pressure-sensitive adhesive layer to obtain a circularly polarizing plate with an pressure-sensitive adhesive sheet.
  • the attachment of the retardation film R1 and the polarizing plate with an interlayer pressure-sensitive adhesive layer is performed by adjusting the angle formed by the slow axis of the first retardation film and the absorption axis of the polarizer when viewed from the side of the first retardation film. was 45 degrees counterclockwise.
  • the (meth)acrylic polymer (A-1) had a weight average molecular weight (Mw) of 2,200,000.
  • (Synthesis example 2) A solution of (meth)acrylic polymer (A-2) was prepared in the same manner as in Synthesis Example 1, except that the monomers used were changed to 94.9 parts by weight of BA, 5.0 parts by weight of AA and 0.1 parts by weight of HBA. got The (meth)acrylic polymer (A-2) had a weight average molecular weight (Mw) of 2,200,000.
  • the pressure-sensitive adhesive sheets of Examples having a gel fraction G2h of less than 60% by weight and a G24h of 60% by weight or more suppress dimensional changes compared to the pressure-sensitive adhesive sheets of Comparative Examples. It is suitable for various applications and exhibits high durability.
  • an adhesive sheet for use in image display devices can be formed.

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  • Organic Chemistry (AREA)
  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Optics & Photonics (AREA)
  • Chemical Kinetics & Catalysis (AREA)
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Abstract

The provided adhesive agent composition includes a (meth)acrylic polymer (A) as a main component, and furthermore includes a cross-linking agent (B). When an adhesive sheet is formed from the adhesive agent composition, the gelling rate G2h of the adhesive sheet at a time when two hours have elapsed from a time T0 at which the adhesive sheet was formed is less than 60 wt%, and the gelling rate G24h of the adhesive sheet at a time when 24 hours have elapsed from the time T0 is equal to or greater than 60 wt%. The adhesive agent composition is suitable for forming an adhesive sheet in which durability is ensured and which is to suppress any change in the dimensions of an optical film included in an optical laminate.

Description

粘着剤組成物、粘着シート、光学積層体及び画像表示装置Adhesive composition, adhesive sheet, optical laminate and image display device
　本発明は、粘着剤組成物、粘着シート、光学積層体及び画像表示装置に関する。 The present invention relates to an adhesive composition, an adhesive sheet, an optical laminate, and an image display device.
　近年、液晶表示装置及びエレクトロルミネセンス（ＥＬ）表示装置（例えば、有機ＥＬ表示装置、無機ＥＬ表示装置）に代表される画像表示装置が急速に普及している。これら各種の画像表示装置は、通常、液晶層、ＥＬ発光層等の画像形成層と、光学フィルム及び粘着シートを含む光学積層体と、の積層構造を有している。粘着シートは、主に、光学積層体に含まれるフィルム間の接合や、画像形成層と光学積層体との接合に使用される。光学フィルムの例は、偏光板、位相差フィルム、及び偏光板と位相差フィルムとを一体化した位相差フィルム付き偏光板である。特許文献１には、光学積層体の一例が開示されている。 In recent years, image display devices typified by liquid crystal display devices and electroluminescence (EL) display devices (eg, organic EL display devices and inorganic EL display devices) have rapidly spread. These various image display devices usually have a laminated structure of an image forming layer such as a liquid crystal layer and an EL light emitting layer, and an optical laminate including an optical film and an adhesive sheet. The pressure-sensitive adhesive sheet is mainly used for bonding between films included in the optical layered body and bonding between the image forming layer and the optical layered body. Examples of the optical film are a polarizing plate, a retardation film, and a polarizing plate with a retardation film in which the polarizing plate and the retardation film are integrated. Patent Literature 1 discloses an example of an optical laminate.
特開２００８－０３１２１４号公報JP 2008-031214 A 特開２００９－９８６６５号公報JP 2009-98665 A
　温度変化に伴う光学フィルムの寸法の過度の変化は、画像表示装置における光漏れや色ムラの原因となる。光漏れや色ムラは、位相差フィルム付き偏光板を用いた、比較的大きなサイズを有する画像表示装置において特に生じやすい。また、額縁（ベゼル）が狭く設計された（狭額縁化された）画像表示装置が普及しつつあり、寸法の変化の抑制が、ますます重要となってきている。寸法の変化を抑えるためには、光学積層体に含まれる粘着シートの弾性率を高めることが考えられる。しかし、単に弾性率を高めるだけでは、粘着シートの耐久性が低下して寸法の変化に追従できないことがある。 Excessive changes in the dimensions of the optical film due to temperature changes cause light leakage and color unevenness in image display devices. Light leakage and color unevenness are particularly likely to occur in a relatively large-sized image display device using a polarizing plate with a retardation film. In addition, image display devices designed with a narrow bezel (narrow bezel) are becoming popular, and suppression of dimensional change is becoming more and more important. In order to suppress the dimensional change, it is conceivable to increase the elastic modulus of the pressure-sensitive adhesive sheet included in the optical layered body. However, simply increasing the elastic modulus may reduce the durability of the pressure-sensitive adhesive sheet, making it impossible to follow changes in dimensions.
　本発明は、光学積層体に含まれる光学フィルムの寸法の変化を抑制しうると共に、耐久性も確保された粘着シートの形成に適した粘着剤組成物の提供を目的とする。 An object of the present invention is to provide a pressure-sensitive adhesive composition suitable for forming a pressure-sensitive adhesive sheet that can suppress changes in the dimensions of the optical film contained in the optical laminate and also ensures durability.
　本発明は、
　（メタ）アクリル系ポリマー（Ａ）を主成分として含む粘着剤組成物であって、
　架橋剤（Ｂ）を更に含み、
　前記粘着剤組成物から粘着シートを形成したときに、
　　前記粘着シートを形成した時点Ｔ0から２時間経過した時点での前記粘着シートのゲル分率Ｇ2hが６０重量％未満であり、
　　前記時点Ｔ0から２４時間経過した時点での前記粘着シートのゲル分率Ｇ24hが６０重量％以上である、粘着剤組成物、
　を提供する。 The present invention
A pressure-sensitive adhesive composition containing a (meth)acrylic polymer (A) as a main component,
further comprising a cross-linking agent (B),
When forming a pressure-sensitive adhesive sheet from the pressure-sensitive adhesive composition,
The gel fraction G 2h of the pressure-sensitive adhesive sheet is less than 60% by weight at the time when 2 hours have passed since the time T 0 of forming the pressure-sensitive adhesive sheet,
The pressure-sensitive adhesive composition, wherein the gel fraction G 24h of the pressure-sensitive adhesive sheet 24 hours after the time T 0 is 60% by weight or more,
I will provide a.
　別の側面において、本発明は、
　上記本発明の粘着剤組成物から形成された粘着シート、
　を提供する。 In another aspect, the invention provides a
A pressure-sensitive adhesive sheet formed from the pressure-sensitive adhesive composition of the present invention,
I will provide a.
　別の側面において、本発明は、
　上記本発明の粘着シートと、光学フィルムと、を含む、光学積層体、
　を提供する。 In another aspect, the invention provides a
An optical laminate comprising the adhesive sheet of the present invention and an optical film,
I will provide a.
　別の側面において、本発明は、
　上記本発明の光学積層体を備える画像表示装置、
　を提供する。 In another aspect, the invention provides a
an image display device comprising the optical layered body of the present invention;
I will provide a.
　本発明による粘着剤組成物は、光学積層体に含まれる光学フィルムの寸法の変化を抑制しうると共に、耐久性も確保された粘着シートの形成に適している。 The pressure-sensitive adhesive composition according to the present invention is suitable for forming a pressure-sensitive adhesive sheet that can suppress changes in the dimensions of the optical film contained in the optical layered body and also ensures durability.
図１は、本発明の粘着シートの一例を模式的に示す断面図である。FIG. 1 is a cross-sectional view schematically showing an example of the pressure-sensitive adhesive sheet of the present invention. 図２は、本発明の光学積層体の一例を模式的に示す断面図である。FIG. 2 is a cross-sectional view schematically showing an example of the optical layered body of the present invention. 図３は、本発明の光学積層体の一例を模式的に示す断面図である。FIG. 3 is a cross-sectional view schematically showing an example of the optical layered body of the present invention. 図４は、本発明の光学積層体の一例を模式的に示す断面図である。FIG. 4 is a cross-sectional view schematically showing an example of the optical layered body of the present invention. 図５は、本発明の光学積層体の一例を模式的に示す断面図である。FIG. 5 is a cross-sectional view schematically showing an example of the optical layered body of the present invention. 図６は、本発明の画像表示装置の一例を模式的に示す断面図である。FIG. 6 is a cross-sectional view schematically showing an example of the image display device of the present invention.
　以下、本発明の実施形態について、図面を参照しながら説明する。本発明は、以下に示す実施形態に限定されない。 Hereinafter, embodiments of the present invention will be described with reference to the drawings. The present invention is not limited to the embodiments shown below.
　本明細書において「（メタ）アクリル」とは、アクリル及びメタクリルを意味する。また、「（メタ）アクリレート」とは、アクリレート及びメタクリレートを意味する。 "(Meth)acrylic" as used herein means acrylic and methacrylic. Moreover, "(meth)acrylate" means acrylate and methacrylate.
［粘着剤組成物］
　本実施形態の粘着剤組成物（Ｉ）は、（メタ）アクリル系ポリマー（Ａ）及び架橋剤（Ｂ）を含む。（メタ）アクリル系ポリマー（Ａ）は、主成分として粘着剤組成物（Ｉ）に含まれる。換言すれば、粘着剤組成物（Ｉ）は、アクリル系粘着剤組成物である。主成分とは、組成物においても最も含有率の大きな成分を意味する。主成分の含有率は、例えば５０重量％以上であり、６０重量％以上、７０重量％以上、７３重量％以上、更には７５重量％以上であってもよい。 [Adhesive composition]
The pressure-sensitive adhesive composition (I) of the present embodiment contains a (meth)acrylic polymer (A) and a cross-linking agent (B). The (meth)acrylic polymer (A) is contained in the pressure-sensitive adhesive composition (I) as a main component. In other words, the pressure-sensitive adhesive composition (I) is an acrylic pressure-sensitive adhesive composition. A main component means the component with the largest content rate also in a composition. The content of the main component is, for example, 50% by weight or more, and may be 60% by weight or more, 70% by weight or more, 73% by weight or more, or even 75% by weight or more.
　粘着剤組成物（Ｉ）から粘着シートを形成したときに、粘着シートを形成した時点Ｔ0から２時間経過した時点での粘着シートのゲル分率Ｇ2hは、６０重量％未満である。また、時点Ｔ0から２４時間経過した時点での粘着シートのゲル分率Ｇ24hは６０重量％以上である。ゲル分率Ｇ2hの上記範囲は、粘着剤組成物（Ｉ）から粘着シートを形成する際の架橋反応が、Ｔ0から２時間が経過するまでの初期段階において比較的ゆっくりと進行することを意味する。上記初期段階における抑制された架橋の速度は、粘着シートにおける架橋構造の均一性を高め、高められた均一性は、粘着シートの耐久性の向上に寄与する。また、ゲル分率Ｇ24hが上記範囲にあることは、光学積層体に含まれる光学フィルムの寸法の変化の抑制に寄与する。 When a pressure-sensitive adhesive sheet is formed from the pressure-sensitive adhesive composition (I), the gel fraction G 2h of the pressure-sensitive adhesive sheet after 2 hours from the time T 0 of forming the pressure-sensitive adhesive sheet is less than 60% by weight. In addition, the gel fraction G 24h of the pressure-sensitive adhesive sheet after 24 hours from time T 0 is 60% by weight or more. The above range of the gel fraction G 2h indicates that the cross-linking reaction in forming the pressure-sensitive adhesive sheet from the pressure-sensitive adhesive composition (I) proceeds relatively slowly in the initial stage from T 0 to 2 hours. means. The suppressed speed of cross-linking in the initial stage enhances the uniformity of the crosslinked structure in the pressure-sensitive adhesive sheet, and the enhanced uniformity contributes to the improvement of the durability of the pressure-sensitive adhesive sheet. Further, the gel fraction G24h being within the above range contributes to suppression of dimensional change of the optical film included in the optical layered body.
　ゲル分率Ｇ2hは、５５重量％以下、５５重量％未満、５０重量％以下、４７重量％以下、４５重量％以下、４５重量％未満、４０重量％以下、３５重量％以下、３０重量％以下、２５重量％以下、２０重量％以下、１５重量％以下、１４重量％以下、１３重量％以下、更には１２重量％以下であってもよい。ゲル分率Ｇ2hの下限は、例えば２重量％以上であり、４重量％以上、５重量％以上、７重量％以上、８重量％以上、９重量％以上、９．５重量％以上、更には９．７重量％以上であってもよい。 The gel fraction G2h is 55% by weight or less, less than 55% by weight, 50% by weight or less, 47% by weight or less, 45% by weight or less, less than 45% by weight, 40% by weight or less, 35% by weight or less, and 30% by weight. 25% by weight or less, 20% by weight or less, 15% by weight or less, 14% by weight or less, 13% by weight or less, or even 12% by weight or less. The lower limit of the gel fraction G 2h is, for example, 2% by weight or more, 4% by weight or more, 5% by weight or more, 7% by weight or more, 8% by weight or more, 9% by weight or more, 9.5% by weight or more, and further may be 9.7% by weight or more.
　ゲル分率Ｇ24hは、６５重量％以上、７０重量％以上、７５重量％以上、８０重量％以上、９０重量％以上、９２重量％以上、更には９４重量％以上であってもよい。ゲル分率Ｇ24hの上限は、例えば９９重量％以下であり、９８重量％以下、９７重量％以下、更には９６重量％以下であってもよい。 The gel fraction G24h may be 65% by weight or more, 70% by weight or more, 75% by weight or more, 80% by weight or more, 90% by weight or more, 92% by weight or more, or even 94% by weight or more. The upper limit of the gel fraction G24h is, for example, 99% by weight or less, and may be 98% by weight or less, 97% by weight or less, or even 96% by weight or less.
　ゲル分率Ｇ2hに対するゲル分率Ｇ24hの比Ｇ24h／Ｇ2hは、例えば２以上であり、３以上、４以上、５以上、６以上、７以上、更には８以上であってもよい。比Ｇ24h／Ｇ2hの上限は、例えば４８以下であり、４５以下、４０以下、３５以下、３０以下、２５以下、２０以下、１５以下、１０以下、更には９．７以下であってもよい。 The ratio G 24h /G 2h of the gel fraction G 24h to the gel fraction G 2h is, for example, 2 or more, and may be 3 or more, 4 or more, 5 or more, 6 or more, 7 or more, or even 8 or more. . The upper limit of the ratio G 24h /G 2h is, for example, 48 or less, 45 or less, 40 or less, 35 or less, 30 or less, 25 or less, 20 or less, 15 or less, 10 or less, or even 9.7 or less. good.
　粘着シートを形成した時点Ｔ0の直後における粘着シートのゲル分率Ｇ0は、３重量％以上５０重量％以下であってもよい。直後とは、典型的には、時点Ｔ0から１０分以内であり、５分以内であってもよい。ゲル分率Ｇ0の上限は、４５重量％以下、４０重量％以下、３５重量％以下、３０重量％以下、２５重量％以下、２０重量％以下、１５重量％以下、１０重量％以下、８重量％以下、６重量％以下、更には５重量％以下であってもよい。 The gel fraction G 0 of the pressure-sensitive adhesive sheet immediately after the time T 0 of forming the pressure-sensitive adhesive sheet may be 3% by weight or more and 50% by weight or less. Immediately after is typically within 10 minutes from time T 0 , and may be within 5 minutes. The upper limit of the gel fraction G 0 is 45% by weight or less, 40% by weight or less, 35% by weight or less, 30% by weight or less, 25% by weight or less, 20% by weight or less, 15% by weight or less, 10% by weight or less, 8 % by weight or less, 6% by weight or less, or even 5% by weight or less.
　ゲル分率Ｇ0に対するゲル分率Ｇ2hの比Ｇ2h／Ｇ0は、例えば２０未満であり、１５以下、１０以下、６以下、５以下、４以下、３以下、２．５以下、２．４以下、更には２．３以下であってもよい。比Ｇ2h／Ｇ0の下限は、例えば１以上であり、１超、１．１以上、１．２以上、１．５以上、１．７以上、２以上、更には２．１以上であってもよい。 The ratio G 2h /G 0 of the gel fraction G 2h to the gel fraction G 0 is, for example, less than 20, 15 or less, 10 or less, 6 or less, 5 or less, 4 or less, 3 or less, 2.5 or less, 2 .4 or less, or even 2.3 or less. The lower limit of the ratio G 2h /G 0 is, for example, 1 or more, more than 1, 1.1 or more, 1.2 or more, 1.5 or more, 1.7 or more, 2 or more, and further 2.1 or more. may
　時点Ｔ0から７日間経過した時点での粘着シートのゲル分率Ｇ7dは、９０重量％以上であってもよく、９１重量％以上、９２重量％以上、９３重量％以上、９４重量％以上、更には９５重量％以上であってもよい。Ｇ7dの上限は、例えば９９．５重量％以下であり、９９重量％以下、更には９８重量％以下であってもよい。 The gel fraction G 7d of the pressure-sensitive adhesive sheet after 7 days have passed from time T 0 may be 90% by weight or more, 91% by weight or more, 92% by weight or more, 93% by weight or more, 94% by weight or more. Furthermore, it may be 95% by weight or more. The upper limit of G7d is, for example, 99.5% by weight or less, and may be 99% by weight or less, or even 98% by weight or less.
　ゲル分率Ｇ24hに対するゲル分率Ｇ7dの比Ｇ7d／Ｇ24hは、例えば１．５以下であり、１．４以下、１．３以下、１．２以下、１．１以下、１．０７以下、１．０５以下、１．０３以下、更には１．０２以下であってもよい。比Ｇ7d／Ｇ24hは、例えば１以上である。 The ratio G 7d /G 24h of the gel fraction G 7d to the gel fraction G 24h is, for example, 1.5 or less, 1.4 or less, 1.3 or less, 1.2 or less, 1.1 or less, 1. 07 or less, 1.05 or less, 1.03 or less, or even 1.02 or less. The ratio G7d / G24h is, for example, 1 or more.
　粘着シートを形成した時点Ｔ0は、粘着シートの形成が終了した時点であり、具体的には、粘着剤組成物（Ｉ）の型に応じて定めることができる。溶剤型及びエマルション型の粘着剤組成物（Ｉ）については、時点Ｔ0は、基材フィルム上に塗布した粘着剤組成物（Ｉ）を含む塗布膜を加熱により乾燥させた後、自然冷却により常温に達した時点として定めることができる。乾燥条件（温度及び時間）は、例えば９０℃及び１００秒間である。常温は、２０－２５℃である。ただし、時点Ｔ0は、２５℃に達した時点により定めることができる。基材フィルムには、ポリエチレンテレフタレート（ＰＥＴ）フィルム等の各種の樹脂フィルムを使用できる。活性エネルギー線硬化型（光硬化型）については、時点Ｔ0は、粘着剤組成物（Ｉ）を含む塗布膜に対する活性エネルギー線の照射により、光硬化の進行が終了した時点として定めることができる。光硬化型の塗布膜は、重合により（メタ）アクリル系ポリマー（Ａ）となる単量体（群）、架橋剤（Ｂ）、並びに必要に応じて、単量体（群）の部分重合物、重合開始剤、添加剤及び溶剤等を含む混合物の塗布膜であってもよい。溶剤型及び光硬化型ともに、時点Ｔ0を定める際の塗布膜の厚さは、例えば、形成した粘着シートの厚さが５０μｍとなる厚さである。 The time T 0 at which the pressure-sensitive adhesive sheet is formed is the time at which the formation of the pressure-sensitive adhesive sheet is completed, and can be specifically determined according to the type of the pressure-sensitive adhesive composition (I). For the solvent-type and emulsion-type adhesive composition (I), at time T 0 , the coating film containing the adhesive composition (I) coated on the base film is dried by heating, and then naturally cooled. It can be defined as the point of time when normal temperature is reached. Drying conditions (temperature and time) are, for example, 90° C. and 100 seconds. Normal temperature is 20-25°C. However, the time T 0 can be determined by the time when the temperature reaches 25°C. Various resin films such as polyethylene terephthalate (PET) film can be used as the base film. For the active energy ray-curable type (photocurable type), the time T 0 can be defined as the time point at which the progress of photocuring is completed by irradiating the coating film containing the pressure-sensitive adhesive composition (I) with an active energy ray. . The photocurable coating film comprises a monomer (group) that becomes a (meth)acrylic polymer (A) by polymerization, a cross-linking agent (B), and, if necessary, a partial polymer of the monomer (group) , a polymerization initiator, an additive, a solvent, and the like. For both the solvent type and the photocurable type, the thickness of the coating film when determining the time T 0 is, for example, the thickness at which the thickness of the adhesive sheet formed is 50 μm.
　各時点のゲル分率は、以下のように評価できる。最初に、各時点の粘着シートから約０．２ｇ掻き取って小片を得る。次に、得られた小片を、ポリテトラフルオロエチレンの延伸多孔質膜（日東電工製ＮＴＦ１１２２、平均孔径０．２μｍ）により包んで凧糸で縛り、試験片とする。次に、得られた試験片の重量Ａを測定する。重量Ａは、粘着シートの小片、延伸多孔質膜及び凧糸の重量の合計である。使用した延伸多孔質膜及び凧糸の合計の重量Ｂは、予め測定しておく。次に、酢酸エチルで満たされた内容積５０ｍＬの容器に試験片を浸漬して、２３℃で１週間静置する。静置後、容器から試験片を取り出し、１３０℃に設定した乾燥機中で２時間乾燥させた後、試験片の重量Ｃを測定する。測定した重量Ａ、重量Ｂ及び重量Ｃから、式：ゲル分率（重量％）＝（Ｃ－Ｂ）／（Ａ－Ｂ）×１００（％）により、ゲル分率を算出する。 The gel fraction at each time point can be evaluated as follows. First, about 0.2 g is scraped from the adhesive sheet for each time point to obtain a small piece. Next, the obtained small piece is wrapped with an expanded porous membrane of polytetrafluoroethylene (NTF1122 manufactured by Nitto Denko, average pore size 0.2 μm) and tied with a kite string to obtain a test piece. Next, the weight A of the obtained test piece is measured. Weight A is the sum of the weights of the adhesive sheet piece, the stretched porous membrane and the kite string. The total weight B of the stretched porous membrane and the kite string used is measured in advance. Next, the test piece is immersed in a container with an internal volume of 50 mL filled with ethyl acetate and allowed to stand at 23° C. for one week. After standing still, the test piece is taken out from the container, dried for 2 hours in a dryer set at 130° C., and then the weight C of the test piece is measured. From the measured weight A, weight B and weight C, the gel fraction is calculated according to the formula: gel fraction (% by weight)=(CB)/(AB)×100(%).
　ゲル分率Ｇ0、Ｇ2h、Ｇ24h及びＧ7dは、例えば、粘着剤組成物に含まれるベースポリマーのガラス転移温度（Ｔｇ）及び組成；架橋剤の種類及び配合量；タッキファイヤ等の添加剤の種類及び配合量；並びに粘着剤組成物から粘着シートを形成するための乾燥（硬化）条件等の様々な要因に基づいて変化する。 The gel fractions G 0 , G 2h , G 24h and G 7d are determined, for example, by the glass transition temperature (Tg) and composition of the base polymer contained in the pressure-sensitive adhesive composition; It varies based on various factors such as the type and compounding amount of the agent; and the drying (curing) conditions for forming a pressure-sensitive adhesive sheet from the pressure-sensitive adhesive composition.
　［（メタ）アクリル系ポリマー（Ａ）］
　（メタ）アクリル系ポリマー（Ａ）は、炭素数１～３０のアルキル基を側鎖に有する（メタ）アクリル系単量体（Ａ１）に由来する構成単位を主たる単位として有することが好ましい。アルキル基は、直鎖状であっても分岐を有していてもよい。（メタ）アクリル系ポリマー（Ａ）は、（メタ）アクリル系単量体（Ａ１）に由来する構成単位を１種又は２種以上有していてもよい。（メタ）アクリル系単量体（Ａ１）の例は、メチル（メタ）アクリレート、エチル（メタ）アクリレート、ｎ－ブチル（メタ）アクリレート、ｓ－ブチル（メタ）アクリレート、ｔ－ブチル（メタ）アクリレート、イソブチル（メタ）アクリレート、ｎ－ペンチル（メタ）アクリレート、イソペンチル（メタ）アクリレート、ｎ－へキシル（メタ）アクリレート、イソヘキシル（メタ）アクリレート、イソヘプチル（メタ）アクリレート、２－エチルヘキシル（メタ）アクリレート、ｎ－オクチル（メタ）アクリレート、イソオクチル（メタ）アクリレート、ｎ－ノニル（メタ）アクリレート、イソノニル（メタ）アクリレート、ｎ－デシル（メタ）アクリレート、イソデシル（メタ）アクリレート、ｎ－ドデシル（メタ）アクリレート（ラウリル（メタ）アクリレート）、ｎ－トリデシル（メタ）アクリレート及びｎ－テトラデシル（メタ）アクリレートである。本明細書において「主たる単位」とは、ポリマーが有する全構成単位のうち、例えば５０重量％以上、好ましくは６０重量％以上、より好ましくは７０重量％以上、更に好ましくは８０重量％以上を占める単位を意味する。 [(Meth) acrylic polymer (A)]
The (meth)acrylic polymer (A) preferably has, as a main unit, a structural unit derived from the (meth)acrylic monomer (A1) having an alkyl group having 1 to 30 carbon atoms in the side chain. The alkyl group may be linear or branched. The (meth)acrylic polymer (A) may have one or more structural units derived from the (meth)acrylic monomer (A1). Examples of (meth) acrylic monomers (A1) include methyl (meth) acrylate, ethyl (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 and n-tetradecyl (meth)acrylate. As used herein, the term "main unit" refers to the total structural units of the polymer, for example 50% by weight or more, preferably 60% by weight or more, more preferably 70% by weight or more, and still more preferably 80% by weight or more. means unit.
　（メタ）アクリル系ポリマー（Ａ）は、長鎖アルキル基を側鎖に有する（メタ）アクリル系単量体（Ａ１）に由来する構成単位を有していてもよい。当該単量体（Ａ１）の例は、ｎ－ドデシル（メタ）アクリレート（ラウリル（メタ）アクリレート）である。本明細書において「長鎖アルキル基」とは、炭素数６～３０のアルキル基を意味する。 The (meth)acrylic polymer (A) may have structural units derived from the (meth)acrylic monomer (A1) having a long-chain alkyl group in its side chain. An example of said monomer (A1) is n-dodecyl (meth)acrylate (lauryl (meth)acrylate). As used herein, the term "long-chain alkyl group" means an alkyl group having 6 to 30 carbon atoms.
　（メタ）アクリル系ポリマー（Ａ）は、ホモポリマーとしたときにガラス転移温度（Ｔｇ）が－７０～－２０℃の範囲にある（メタ）アクリル系単量体（Ａ１）に由来する構成単位を有していてもよい。当該単量体（Ａ１）の例は、ｎ－ブチルアクリレートである。 The (meth)acrylic polymer (A) is a structural unit derived from the (meth)acrylic monomer (A1) having a glass transition temperature (Tg) in the range of −70 to −20° C. when homopolymerized. may have An example of said monomer (A1) is n-butyl acrylate.
　（メタ）アクリル系ポリマー（Ａ）は、（メタ）アクリル系単量体（Ａ１）に由来する構成単位以外の構成単位を有していてもよい。当該構成単位は、（メタ）アクリル系単量体（Ａ１）と共重合可能な単量体（Ａ２）に由来する。（メタ）アクリル系ポリマー（Ａ）は、当該構成単位を１種又は２種以上有していてもよい。 The (meth)acrylic polymer (A) may have structural units other than the structural units derived from the (meth)acrylic monomer (A1). The structural unit is derived from the monomer (A2) copolymerizable with the (meth)acrylic monomer (A1). The (meth)acrylic polymer (A) may have one or more of these structural units.
　単量体（Ａ２）の例は、芳香環含有単量体である。芳香環含有単量体は、芳香環含有（メタ）アクリル系単量体であってもよい。芳香環含有単量体の例は、フェニル（メタ）アクリレート、フェノキシエチル（メタ）アクリレート、ベンジル（メタ）アクリレート、フェノキシジエチレングリコール（メタ）アクリレート、エチレンオキサイド変性ノニルフェノール（メタ）アクリレート、ヒドロキシエチル化β－ナフトール（メタ）アクリレート及びビフェニル（メタ）アクリレートである。（メタ）アクリル系ポリマー（Ａ）における芳香環含有単量体に由来する構成単位の含有率は、例えば０～５０重量％であり、１～３０重量％、５～２５重量％、８～２０重量％、１０～１８重量％、更には１２～１６重量％であってもよい。粘着剤組成物（Ｉ）における架橋剤（Ｂ）の配合量が増すと、架橋剤（Ｂ）の自己重合体が形成されることがある。芳香環含有単量体に由来する構成単位を（メタ）アクリル系ポリマー（Ａ）が有することは、（メタ）アクリル系ポリマー（Ａ）と、架橋剤（Ｂ）及びその自己重合体との相溶性を向上させる。相溶性の向上は、例えば自己重合体の析出が抑制されることによって、粘着シートの均一性の向上に寄与しうる。 An example of the monomer (A2) is an aromatic ring-containing monomer. The aromatic ring-containing monomer may be an aromatic ring-containing (meth)acrylic monomer. Examples of aromatic ring-containing monomers include phenyl (meth) acrylate, phenoxyethyl (meth) acrylate, benzyl (meth) acrylate, phenoxydiethylene glycol (meth) acrylate, ethylene oxide-modified nonylphenol (meth) acrylate, hydroxyethylated β- naphthol (meth)acrylate and biphenyl (meth)acrylate. The content of structural units derived from aromatic ring-containing monomers in the (meth)acrylic polymer (A) is, for example, 0 to 50% by weight, 1 to 30% by weight, 5 to 25% by weight, 8 to 20% by weight. % by weight, 10-18% by weight, or even 12-16% by weight. When the blending amount of the cross-linking agent (B) in the pressure-sensitive adhesive composition (I) increases, a self-polymer of the cross-linking agent (B) may be formed. Having a structural unit derived from an aromatic ring-containing monomer in the (meth)acrylic polymer (A) is a phase between the (meth)acrylic polymer (A), the cross-linking agent (B), and its self-polymer. improve solubility. Improved compatibility can contribute to improved uniformity of the pressure-sensitive adhesive sheet, for example, by suppressing precipitation of the self-polymer.
　単量体（Ａ２）の別の例は、水酸基含有単量体である。水酸基含有単量体は、水酸基含有（メタ）アクリル系単量体であってもよい。水酸基含有単量体の例は、２－ヒドロキシエチル（メタ）アクリレート、３－ヒドロキシプロピル（メタ）アクリレート、４－ヒドロキシブチル（メタ）アクリレート、６－ヒドロキシヘキシル（メタ）アクリレート、８－ヒドロキシオクチル（メタ）アクリレート、１０－ヒドロキシデシル（メタ）アクリレート及び１２－ヒドロキシラウリル（メタ）アクリレート等のヒドロキシアルキル（メタ）アクリレート、並びに（４－ヒドロキシメチルシクロヘキシル)－メチルアクリレートである。なお、水酸基は、各種の架橋剤と反応しうる。形成する架橋構造の均一性を高める観点からは、（メタ）アクリル系ポリマー（Ａ）における水酸基含有単量体に由来する構成単位の含有率は、１重量％以下であってもよく、０．５重量％以下、更には０．１重量％以下であってもよく、０重量％であっても（当該構成単位を含まなくても）よい。 Another example of the monomer (A2) is a hydroxyl group-containing monomer. The hydroxyl group-containing monomer may be a hydroxyl group-containing (meth)acrylic monomer. Examples of hydroxyl-containing monomers are 2-hydroxyethyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, 6-hydroxyhexyl (meth)acrylate, 8-hydroxyoctyl ( hydroxyalkyl (meth)acrylates such as meth)acrylates, 10-hydroxydecyl (meth)acrylate and 12-hydroxylauryl (meth)acrylate, and (4-hydroxymethylcyclohexyl)-methylacrylate. In addition, the hydroxyl group can react with various cross-linking agents. From the viewpoint of improving the uniformity of the crosslinked structure to be formed, the content of structural units derived from hydroxyl group-containing monomers in the (meth)acrylic polymer (A) may be 1% by weight or less. It may be 5% by weight or less, further 0.1% by weight or less, or 0% by weight (without including the structural unit).
　単量体（Ａ２）は、カルボキシル基含有単量体、アミノ基含有単量体、アミド基含有単量体であってもよい。カルボキシル基含有単量体の例は、(メタ)アクリル酸、カルボキシエチル(メタ)アクリレート、カルボキシペンチル(メタ)アクリレート、イタコン酸、マレイン酸、フマール酸及びクロトン酸である。アミノ基含有単量体の例は、Ｎ，Ｎ－ジメチルアミノエチル（メタ）アクリレート及びＮ，Ｎ－ジメチルアミノプロピル（メタ）アクリレートである。アミド基含有単量体の例は、（メタ）アクリルアミド、Ｎ，Ｎ－ジメチル（メタ）アクリルアミド、Ｎ，Ｎ－ジエチル（メタ）アクリルアミド、Ｎ－イソプロピルアクリルアミド、Ｎ－メチル（メタ）アクリルアミド、Ｎ－ブチル（メタ）アクリルアミド、Ｎ－ヘキシル（メタ）アクリルアミド、Ｎ－メチロール（メタ）アクリルアミド、Ｎ－メチロール－Ｎ－プロパン（メタ）アクリルアミド、アミノメチル（メタ）アクリルアミド、アミノエチル（メタ）アクリルアミド、メルカプトメチル（メタ）アクリルアミド及びメルカプトエチル（メタ）アクリルアミド等のアクリルアミド系単量体；Ｎ－（メタ）アクリロイルモルホリン、Ｎ－（メタ）アクリロイルピペリジン及びＮ－（メタ）アクリロイルピロリジン等のＮ－アクリロイル複素環単量体；並びにＮ－ビニルピロリドン及びＮ－ビニル－ε－カプロラクタム等のＮ－ビニル基含有ラクタム系単量体である。カルボキシル基含有単量体、特にアクリル酸、に由来する構成単位を（メタ）アクリル系ポリマー（Ａ）が有することで、例えば、架橋剤（Ｂ）の自己重合性を高めることができる。架橋剤（Ｂ）の自己重合性の向上は、特に、加湿環境下における粘着シートの剥がれの抑制や、架橋剤（Ｂ）の含有率が高い系における粘着シートの物性の安定化に寄与しうる。 The monomer (A2) may be a carboxyl group-containing monomer, an amino group-containing monomer, or an amide 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. Examples of amino group-containing monomers are N,N-dimethylaminoethyl (meth)acrylate and N,N-dimethylaminopropyl (meth)acrylate. Examples of amide group-containing monomers are (meth)acrylamide, N,N-dimethyl(meth)acrylamide, N,N-diethyl(meth)acrylamide, N-isopropylacrylamide, N-methyl(meth)acrylamide, N- Butyl (meth)acrylamide, N-hexyl (meth)acrylamide, N-methylol (meth)acrylamide, N-methylol-N-propane (meth)acrylamide, aminomethyl (meth)acrylamide, aminoethyl (meth)acrylamide, mercaptomethyl (Meth) acrylamide-based monomers such as mercaptoethyl (meth) acrylamide; and N-vinyl group-containing lactam monomers such as N-vinylpyrrolidone and N-vinyl-ε-caprolactam. When the (meth)acrylic polymer (A) has structural units derived from a carboxyl group-containing monomer, particularly acrylic acid, for example, the self-polymerizability of the cross-linking agent (B) can be enhanced. Improvement of the self-polymerization of the cross-linking agent (B) can contribute to suppression of peeling of the pressure-sensitive adhesive sheet in a humidified environment, and stabilization of physical properties of the pressure-sensitive adhesive sheet in a system having a high content of the cross-linking agent (B). .
　単量体（Ａ２）は、多官能性単量体であってもよい。多官能性単量体の例は、ヘキサンジオールジ（メタ）アクリレート（１，６－ヘキサンジオールジ（メタ）アクリレート）、ブタンジオールジ（メタ）アクリレート、（ポリ）エチレングリコールジ（メタ）アクリレート、（ポリ）プロピレングリコールジ（メタ）アクリレート、ネオペンチルグリコールジ（メタ）アクリレート、ペンタエリスリトールジ（メタ）アクリレート、ペンタエリスリトールトリ（メタ）アクリレート、ジペンタエリスリトールヘキサ（メタ）アクリレート、トリメチロールプロパントリ（メタ）アクリレート、テトラメチロールメタントリ（メタ）アクリレート、アリル（メタ）アクリレート、ビニル（メタ）アクリレート、エポキシアクリレート、ポリエステルアクリレート及びウレタンアクリレート等の多官能アクリレート；並びにジビニルベンゼンである。多官能アクリレートは、好ましくは１，６－ヘキサンジオールジアクリレート、ジペンタエリスリトールヘキサ（メタ）アクリレートである。 The monomer (A2) may be a polyfunctional monomer. Examples of multifunctional monomers are hexanediol di(meth)acrylate (1,6-hexanediol di(meth)acrylate), butanediol di(meth)acrylate, (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, trimethylolpropane tri( polyfunctional acrylates such as meth)acrylates, tetramethylolmethane tri(meth)acrylates, allyl (meth)acrylates, vinyl (meth)acrylates, epoxy acrylates, polyester acrylates and urethane acrylates; and divinylbenzene. Polyfunctional acrylates are preferably 1,6-hexanediol diacrylate and dipentaerythritol hexa(meth)acrylate.
　（メタ）アクリル系ポリマー（Ａ）におけるカルボキシル基含有単量体、アミノ基含有単量体、アミド基含有単量体及び多官能性単量体に由来する構成単位の含有率の合計は、好ましくは２０重量％以下であり、より好ましくは１０重量％以下、更に好ましくは８重量％以下である。（メタ）アクリル系ポリマー（Ａ）が当該構成単位を有する場合、含有率の合計は、例えば０．０１重量％以上であり、０．０５重量％以上であってもよい。（メタ）アクリル系ポリマー（Ａ）は、多官能性単量体に由来する構成単位を含まなくてもよい。 The total content of structural units derived from the carboxyl group-containing monomer, amino group-containing monomer, amide group-containing monomer and polyfunctional monomer in the (meth)acrylic polymer (A) is preferably is 20% by weight or less, more preferably 10% by weight or less, and still more preferably 8% by weight or less. When the (meth)acrylic polymer (A) has the structural unit, the total content is, for example, 0.01% by weight or more, and may be 0.05% by weight or more. The (meth)acrylic polymer (A) may not contain structural units derived from polyfunctional monomers.
　その他の単量体（Ａ２）の例は、（メタ）アクリル酸２－メトキシエチル、（メタ）アクリル酸２－エトキシエチル、（メタ）アクリル酸メトキシトリエチレングリコール、（メタ）アクリル酸３－メトキシプロピル、（メタ）アクリル酸３－エトキシプロピル、（メタ）アクリル酸４－メトキシブチル及び（メタ）アクリル酸４－エトキシブチル等の（メタ）アクリル酸アルコキシアルキルエステル；（メタ）アクリル酸グリシジル及び（メタ）アクリル酸メチルグリシジル等のエポキシ基含有単量体；ビニルスルホン酸ナトリウム等のスルホン酸基含有単量体；リン酸基含有単量体；（メタ）アクリル酸シクロペンチル、（メタ）アクリル酸シクロヘキシル及び（メタ）アクリル酸イソボルニル等の脂環式炭化水素基を有する（メタ）アクリル酸エステル；酢酸ビニル及びプロピオン酸ビニル等のビニルエステル類；スチレン及びビニルトルエン等の芳香族ビニル化合物；エチレン、プロピレン、ブタジエン、イソプレン及びイソブチレン等のオレフィン類、又はジエン類；ビニルアルキルエーテル等のビニルエーテル類；並びに塩化ビニルである。 Examples of other monomers (A2) include 2-methoxyethyl (meth)acrylate, 2-ethoxyethyl (meth)acrylate, methoxytriethylene glycol (meth)acrylate, and 3-methoxy (meth)acrylate. Alkoxyalkyl (meth)acrylates such as propyl, 3-ethoxypropyl (meth)acrylate, 4-methoxybutyl (meth)acrylate and 4-ethoxybutyl (meth)acrylate; glycidyl (meth)acrylate and ( Epoxy group-containing monomers such as methyl glycidyl acrylate; sulfonic acid group-containing monomers such as sodium vinyl sulfonate; phosphoric acid group-containing monomers; cyclopentyl (meth)acrylate, cyclohexyl (meth)acrylate and (meth)acrylic acid esters having an alicyclic hydrocarbon group such as isobornyl (meth)acrylate; vinyl esters such as vinyl acetate and vinyl propionate; aromatic vinyl compounds such as styrene and vinyltoluene; ethylene, propylene olefins, such as butadiene, isoprene and isobutylene, or dienes; vinyl ethers, such as vinyl alkyl ether; and vinyl chloride.
　（メタ）アクリル系ポリマー（Ａ）における上記その他の単量体（Ａ２）に由来する構成単位の含有率の合計は、例えば３０重量％以下であり、１０重量％以下であってもよく、０重量％である（当該構成単位を含まない）ことが好ましい。 The total content of structural units derived from the other monomer (A2) in the (meth)acrylic polymer (A) is, for example, 30% by weight or less, and may be 10% by weight or less, or 0 % by weight (not including the structural unit).
　（メタ）アクリル系ポリマー（Ａ）は、上述した１種又は２種以上の単量体を公知の方法により重合して形成できる。単量体と、単量体の部分重合物とを重合してもよい。重合は、例えば、溶液重合、乳化重合、塊状重合、熱重合、活性エネルギー線重合により実施できる。光学的透明性に優れる粘着シートを形成できることから、溶液重合、活性エネルギー線重合が好ましい。重合は、単量体及び／又は部分重合物と酸素との接触を避けて実施することが好ましく、このために、例えば、窒素等の不活性ガス雰囲気下における重合、あるいは樹脂フィルム等により酸素を遮断した状態での重合を採用できる。形成する（メタ）アクリル系ポリマー（Ａ）は、ランダム共重合体、ブロック共重合体、グラフト共重合体等のいずれの態様であってもよい。 The (meth)acrylic polymer (A) can be formed by polymerizing one or more of the above monomers by a known method. A monomer and a partial polymer of the monomer may be polymerized. Polymerization can be carried out, for example, by solution polymerization, emulsion polymerization, bulk polymerization, thermal polymerization, or active energy ray polymerization. Solution polymerization and active energy ray polymerization are preferred because they can form a pressure-sensitive adhesive sheet with excellent optical transparency. Polymerization is preferably carried out while avoiding contact of the monomer and/or partial polymer with oxygen. Polymerization in shutdown can be employed. The (meth)acrylic polymer (A) to be formed may be in any form such as a random copolymer, a block copolymer, or a graft copolymer.
　（メタ）アクリル系ポリマー（Ａ）を形成する重合系は、１種又は２種以上の重合開始剤を含んでいてもよい。重合開始剤の種類は、重合反応により選択でき、例えば、熱重合開始剤、光重合開始剤であってもよい。 The polymerization system forming the (meth)acrylic polymer (A) may contain one or more polymerization initiators. The type of polymerization initiator can be selected depending on the polymerization reaction, and may be, for example, a thermal polymerization initiator or a photopolymerization initiator.
　溶液重合に使用する溶媒は、例えば、酢酸エチル、酢酸ｎ－ブチル等のエステル類；トルエン、ベンゼン等の芳香族炭化水素類；ｎ－ヘキサン、ｎ－ヘプタン等の脂肪族炭化水素類；シクロヘキサン、メチルシクロヘキサン等の脂環式炭化水素類；メチルエチルケトン、メチルイソブチルケトン等のケトン類である。ただし、溶媒は上記例に限定されない。溶媒は、２種以上の溶媒の混合溶媒であってもよい。 Solvents used for solution polymerization include esters such as ethyl acetate and n-butyl acetate; aromatic hydrocarbons such as toluene and benzene; aliphatic hydrocarbons such as n-hexane and n-heptane; alicyclic hydrocarbons such as methylcyclohexane; and ketones such as methyl ethyl ketone and methyl isobutyl ketone. However, the solvent is not limited to the above examples. The solvent may be a mixed solvent of two or more solvents.
　溶液重合に使用する重合開始剤は、例えば、アゾ系重合開始剤、過酸化物系重合開始剤、レドックス系重合開始剤である。過酸化物系重合開始剤は、例えば、ジベンゾイルペルオキシド、ｔ－ブチルペルマレエートである。なかでも、特開２００２－６９４１１号公報に開示のアゾ系重合開始剤が好ましい。当該アゾ系重合開始剤は、例えば、２，２’－アゾビスイソブチロニトリル（ＡＩＢＮ）、２，２’－アゾビス－２－メチルブチロニトリル、２，２’－アゾビス（２－メチルプロピオン酸）ジメチル、４，４’－アゾビス－４－シアノバレリアン酸である。ただし、重合開始剤は上記例に限定されない。アゾ系重合開始剤の使用量は、例えば、単量体の全量１００重量部に対して０．０５～０．５重量部であり、０．１～０．３重量部であってもよい。 Polymerization initiators used for solution polymerization are, for example, azo polymerization initiators, peroxide polymerization initiators, and redox polymerization initiators. Peroxide polymerization initiators are, for example, dibenzoyl peroxide and t-butyl permaleate. Among them, the azo polymerization initiator disclosed in JP-A-2002-69411 is preferable. The azo polymerization initiator, for example, 2,2'-azobisisobutyronitrile (AIBN), 2,2'-azobis-2-methylbutyronitrile, 2,2'-azobis (2-methylpropion acid) dimethyl, 4,4'-azobis-4-cyanovaleric acid. However, the polymerization initiator is not limited to the above examples. The amount of the azo polymerization initiator used is, for example, 0.05 to 0.5 parts by weight, and may be 0.1 to 0.3 parts by weight, per 100 parts by weight of the total amount of the monomers.
　活性エネルギー線重合に使用する活性エネルギー線は、例えば、α線、β線、γ線、中性子線、電子線等の電離性放射線、及び紫外線である。活性エネルギー線は、紫外線が好ましい。紫外線の照射による重合は、光重合とも称される。活性エネルギー線重合の重合系は、典型的には、光重合開始剤を含む。活性エネルギー重合の重合条件は、（メタ）アクリル系ポリマー（Ａ）が形成される限り、限定されない。 The active energy rays used for active energy ray polymerization are, for example, ionizing radiation such as α-rays, β-rays, γ-rays, neutron beams and electron beams, and ultraviolet rays. The active energy rays are preferably ultraviolet rays. Polymerization by irradiation with ultraviolet rays is also called photopolymerization. A polymerization system for active energy ray polymerization typically contains a photopolymerization initiator. Polymerization conditions for active energy polymerization are not limited as long as the (meth)acrylic polymer (A) is formed.
　光重合開始剤は、例えば、ベンゾインエーテル系光重合開始剤、アセトフェノン系光重合開始剤、α－ケトール系光重合開始剤、芳香族スルホニルクロリド系光重合開始剤、光活性オキシム系光重合開始剤、ベンゾイン系光重合開始剤、ベンジル系光重合開始剤、ベンゾフェノン系光重合開始剤、ケタール系光重合開始剤、チオキサントン系光重合開始剤である。ただし、光重合開始剤は上記例に限定されない。 Photopolymerization initiators include, for example, benzoin ether-based photopolymerization initiators, acetophenone-based photopolymerization initiators, α-ketol-based photopolymerization initiators, aromatic sulfonyl chloride-based photopolymerization initiators, and photoactive oxime-based photopolymerization initiators. , a benzoin-based photopolymerization initiator, a benzyl-based photopolymerization initiator, a benzophenone-based photopolymerization initiator, a ketal-based photopolymerization initiator, and a thioxanthone-based photopolymerization initiator. However, the photopolymerization initiator is not limited to the above examples.
　ベンゾインエーテル系光重合開始剤は、例えば、ベンゾインメチルエーテル、ベンゾインエチルエーテル、ベンゾインプロピルエーテル、ベンゾインイソプロピルエーテル、ベンゾインイソブチルエーテル、２，２－ジメトキシ－１，２－ジフェニルエタン－１－オン、アニソールメチルエーテルである。アセトフェノン系光重合開始剤は、例えば、２，２－ジエトキシアセトフェノン、２，２－ジメトキシ－２－フェニルアセトフェノン、１－ヒドロキシシクロヘキシルフェニルケトン、４－フェノキシジクロロアセトフェノン、４－（ｔ－ブチル）ジクロロアセトフェノンである。α－ケトール系光重合開始剤は、例えば、２－メチル－２－ヒドロキシプロピオフェノン、１－［４－（２－ヒドロキシエチル）フェニル］－２－メチルプロパン－１－オンである。芳香族スルホニルクロリド系光重合開始剤は、例えば、２－ナフタレンスルホニルクロライドである。光活性オキシム系光重合開始剤は、例えば、１－フェニル－１，１－プロパンジオン－２－（ｏ－エトキシカルボニル）－オキシムである。ベンゾイン系光重合開始剤は、例えば、ベンゾインである。ベンジル系光重合開始剤は、例えば、ベンジルである。ベンゾフェノン系光重合開始剤は、例えば、ベンゾフェノン、ベンゾイル安息香酸、３，３’－ジメチル－４－メトキシベンゾフェノン、ポリビニルベンゾフェノン、α－ヒドロキシシクロヘキシルフェニルケトンである。ケタール系光重合開始剤は、例えば、ベンジルジメチルケタールである。チオキサントン系光重合開始剤は、例えば、チオキサントン、２－クロロチオキサントン、２－メチルチオキサントン、２，４－ジメチルチオキサントン、イソプロピルチオキサントン、２，４－ジイソプロピルチオキサントン、ドデシルチオキサントンである。 Benzoin ether-based photopolymerization initiators include, for example, benzoin methyl ether, benzoin ethyl ether, benzoin propyl ether, benzoin isopropyl ether, benzoin isobutyl ether, 2,2-dimethoxy-1,2-diphenylethan-1-one, anisolemethyl is ether. Acetophenone-based photopolymerization initiators include, for example, 2,2-diethoxyacetophenone, 2,2-dimethoxy-2-phenylacetophenone, 1-hydroxycyclohexylphenylketone, 4-phenoxydichloroacetophenone, 4-(t-butyl)dichloro Acetophenone. Examples of α-ketol photopolymerization initiators are 2-methyl-2-hydroxypropiophenone and 1-[4-(2-hydroxyethyl)phenyl]-2-methylpropan-1-one. The aromatic sulfonyl chloride photopolymerization initiator is, for example, 2-naphthalenesulfonyl chloride. A photoactive oxime-based photopolymerization initiator is, for example, 1-phenyl-1,1-propanedione-2-(o-ethoxycarbonyl)-oxime. A benzoin-based photopolymerization initiator is, for example, benzoin. A benzylic photopolymerization initiator is, for example, benzyl. Examples of benzophenone-based photopolymerization initiators include benzophenone, benzoylbenzoic acid, 3,3'-dimethyl-4-methoxybenzophenone, polyvinylbenzophenone, and α-hydroxycyclohexylphenyl ketone. A ketal photopolymerization initiator is, for example, benzyl dimethyl ketal. Thioxanthone-based photopolymerization initiators are, for example, thioxanthone, 2-chlorothioxanthone, 2-methylthioxanthone, 2,4-dimethylthioxanthone, isopropylthioxanthone, 2,4-diisopropylthioxanthone, and dodecylthioxanthone.
　光重合開始剤の使用量は、例えば、単量体の全量１００重量部に対して０．０１～１重量部であり、０．０５～０．５重量部であってもよい。 The amount of the photopolymerization initiator used is, for example, 0.01 to 1 part by weight, and may be 0.05 to 0.5 part by weight, based on 100 parts by weight of the total amount of the monomers.
　（メタ）アクリル系ポリマー（Ａ）の重量平均分子量（Ｍｗ）は、例えば、１００万～２８０万であり、粘着シートの耐久性及び耐熱性の観点からは、１２０万以上、更には１４０万以上であってもよい。本明細書におけるポリマー及びオリゴマーの重量平均分子量（Ｍｗ）は、ＧＰＣ（ゲル・パーミエーション・クロマトグラフィー）の測定に基づく値（ポリスチレン換算）である。 The weight average molecular weight (Mw) of the (meth)acrylic polymer (A) is, for example, 1,000,000 to 2,800,000, and from the viewpoint of the durability and heat resistance of the pressure-sensitive adhesive sheet, it is 1,200,000 or more, further 1,400,000 or more. may be The weight average molecular weight (Mw) of polymers and oligomers in this specification is a value (converted to polystyrene) based on GPC (gel permeation chromatography) measurement.
　粘着剤組成物（Ｉ）における（メタ）アクリル系ポリマー（Ａ）の含有率は、固形分比で、例えば５０重量％以上であり、６０重量％以上、７０重量％以上、更には８０重量％以上であってもよい。含有率の上限は、例えば９９重量％以下であり、９７重量％以下、９５重量％以下、９３重量％以下、更には９０重量％以下であってもよい。 The content of the (meth)acrylic polymer (A) in the pressure-sensitive adhesive composition (I) is, for example, 50% by weight or more, 60% by weight or more, 70% by weight or more, and further 80% by weight in terms of solid content. or more. The upper limit of the content is, for example, 99% by weight or less, and may be 97% by weight or less, 95% by weight or less, 93% by weight or less, or even 90% by weight or less.
　［架橋剤（Ｂ）］
　架橋剤（Ｂ）は、典型的には、１分子あたり２以上の架橋反応基を有する多官能性架橋剤である。架橋剤（Ｂ）は、１分子あたり３以上の架橋反応基を有する３官能以上の架橋剤であってもよい。１分子あたりの架橋反応基の数の上限は、例えば５である。 [Crosslinking agent (B)]
Cross-linking agent (B) is typically a polyfunctional cross-linking agent having two or more cross-linking reactive groups per molecule. The cross-linking agent (B) may be a tri- or higher functional cross-linking agent having 3 or more cross-linking reactive groups per molecule. The upper limit of the number of cross-linking reactive groups per molecule is 5, for example.
　架橋剤（Ｂ）は、例えば、イソシアネート系架橋剤である。イソシアネート系架橋剤は、架橋反応基としてイソシアネート基を含む。イソシアネート系の架橋剤（Ｂ）は、芳香族イソシアネート化合物、脂環族イソシアネート化合物、脂肪族イソシアネート化合物であってもよい。 The cross-linking agent (B) is, for example, an isocyanate-based cross-linking agent. The isocyanate-based cross-linking agent contains an isocyanate group as a cross-linking reactive group. The isocyanate-based cross-linking agent (B) may be an aromatic isocyanate compound, an alicyclic isocyanate compound, or an aliphatic isocyanate compound.
　架橋剤（Ｂ）に使用しうる芳香族イソシアネート化合物の例は、フェニレンジイソシアネート、２，４－トリレンジイソシアネート、２，６－トリレンジイソシアネート、２，２’－ジフェニルメタンジイソシアネート、４，４’－ジフェニルメタンジイソシアネート、４，４’－トルイジンジイソシアネート、４，４’－ジフェニルエーテルジイソシアネート、４，４’－ジフェニルジイソシアネート及び１，５－ナフタレンジイソシアネート、キシリレンジイソシアネートである。 Examples of aromatic isocyanate compounds that can be used for the cross-linking agent (B) include phenylene diisocyanate, 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, 2,2′-diphenylmethane diisocyanate, and 4,4′-diphenylmethane. diisocyanate, 4,4'-toluidine diisocyanate, 4,4'-diphenyl ether diisocyanate, 4,4'-diphenyl diisocyanate and 1,5-naphthalene diisocyanate, xylylene diisocyanate.
　架橋剤（Ｂ）に使用しうる脂環族イソシアネート化合物の例は、１，３－シクロペンテンジイソシアネート、１，３－シクロヘキサンジイソシアネート、１，４－シクロヘキサンジイソシアネート、イソホロンジイソシアネート、水素添加ジフェニルメタンジイソシアネート、水素添加キシリレンジイソシアネート、水素添加トリレンジイソシアネート及び水素添加テトラメチルキシリレンジイソシアネートである。 Examples of alicyclic isocyanate compounds that can be used for the cross-linking agent (B) include 1,3-cyclopentene diisocyanate, 1,3-cyclohexane diisocyanate, 1,4-cyclohexane diisocyanate, isophorone diisocyanate, hydrogenated diphenylmethane diisocyanate, hydrogenated xyloxy diisocyanate, hydrogenated tolylene diisocyanate and hydrogenated tetramethylxylylene diisocyanate.
　架橋剤（Ｂ）に使用しうる脂肪族イソシアネート化合物の例は、トリメチレンジイソシアネート、テトラメチレンジイソシアネート、ヘキサメチレンジイソシアネート、ペンタメチレンジイソシアネート、１，２－プロピレンジイソシアネート、１，３－ブチレンジイソシアネート、ドデカメチレンジイソシアネート及び２，４，４－トリメチルヘキサメチレンジイソシアネートである。 Examples of aliphatic isocyanate compounds that can be used as the cross-linking agent (B) include trimethylene diisocyanate, tetramethylene diisocyanate, hexamethylene diisocyanate, pentamethylene diisocyanate, 1,2-propylene diisocyanate, 1,3-butylene diisocyanate, and dodecamethylene diisocyanate. and 2,4,4-trimethylhexamethylene diisocyanate.
　架橋剤（Ｂ）は、上記イソシアネート化合物の誘導体であってもよい。誘導体の例は、多量体（２量体、３量体、５量体等）、トリメチロールプロパン等の多価アルコールに付加して得た付加物（アダクト体）、ウレア変性体、ビウレット変性体、アロファネート変性体、イソシアヌレート変性体、カルボジイミド変性体、並びにポリエーテルポリオール、ポリエステルポリオール、アクリルポリオール、ポリブタジエンポリオール、ポリイソプレンポリオール等に付加して得たウレタンプレポリマーである。 The cross-linking agent (B) may be a derivative of the above isocyanate compound. Examples of derivatives include multimers (dimers, trimers, pentamers, etc.), adducts (adducts) obtained by adding polyhydric alcohols such as trimethylolpropane, urea modified products, and biuret modified products. , allophanate-modified, isocyanurate-modified, carbodiimide-modified, and urethane prepolymers obtained by addition to polyether polyol, polyester polyol, acrylic polyol, polybutadiene polyol, polyisoprene polyol, and the like.
　架橋剤（Ｂ）は、好ましくは芳香族イソシアネート化合物及びその誘導体であり、より好ましくは、トリレンジイソシアネート及びその誘導体（換言すれば、トリレンジイソシアネート系（ＴＤＩ系）架橋剤）である。ＴＤＩ系架橋剤は、キシリレンジイソシアネート及びその誘導体（換言すれば、キシリレンジイソシアネート系（ＸＤＩ系）架橋剤）に比べて反応の均一性に優れる。ＴＤＩ系架橋剤の例は、トリレンジイソシアネートと多官能アルコールとの付加物であり、より具体的な例は、トリメチロールプロパン／トリレンジイソシアネート３量体付加物である。 The cross-linking agent (B) is preferably an aromatic isocyanate compound and its derivatives, more preferably tolylene diisocyanate and its derivatives (in other words, tolylene diisocyanate-based (TDI-based) cross-linking agent). TDI-based cross-linking agents are superior to xylylene diisocyanate and its derivatives (in other words, xylylene diisocyanate-based (XDI-based) cross-linking agents) in terms of reaction uniformity. An example of a TDI-based cross-linking agent is an adduct of tolylene diisocyanate and a polyfunctional alcohol, and a more specific example is a trimethylolpropane/tolylene diisocyanate trimer adduct.
　架橋剤（Ｂ）には市販品を使用できる。市販品の例は、ミリオネートＭＴ、ミリオネートＭＴＬ、ミリオネートＭＲ－２００、ミリオネートＭＲ－４００、コロネートＬ、コロネートＨＬ及びコロネートＨＸ（以上、東ソー製：いずれも商品名）、並びにタケネートＤ－１０２、タケネートＤ－１０３、タケネートＤ－１１０Ｎ、タケネートＤ－１２０Ｎ、タケネートＤ－１４０Ｎ、タケネートＤ－１６０Ｎ、タケネートＤ－１６５Ｎ、タケネートＤ－１７０ＨＮ、タケネートＤ－１７８Ｎ、タケネート５００及びタケネート６００（以上、三井化学製；いずれも商品名）である。架橋剤（Ｂ）には、コロネートＬ、タケネートＤ－１０２及びタケネートＤ－１０３（いずれもトリメチロールプロパン／トリレンジイソシアネート３量体付加物）を好ましく使用できる。 A commercially available product can be used for the cross-linking agent (B). Examples of commercially available products include Millionate MT, Millionate MTL, Millionate MR-200, Millionate MR-400, Coronate L, Coronate HL and Coronate HX (manufactured by Tosoh; all trade names), Takenate D-102 and Takenate D. -103, Takenate D-110N, Takenate D-120N, Takenate D-140N, Takenate D-160N, Takenate D-165N, Takenate D-170HN, Takenate D-178N, Takenate 500 and Takenate 600 (manufactured by Mitsui Chemicals; Both are trade names). As the cross-linking agent (B), Coronate L, Takenate D-102 and Takenate D-103 (all of which are trimethylolpropane/tolylene diisocyanate trimer adducts) can be preferably used.
　粘着剤組成物（Ｉ）における架橋剤（Ｂ）の配合量は、(メタ)アクリル系ポリマー（Ａ）１００重量部に対して、例えば５重量部以上であり、６重量部以上、７重量部以上、８重量部以上、９重量部以上、１０重量部以上、１０重量部超、更には１１重量部以上であってもよい。配合量の上限は、例えば３０重量部以下であり、２８重量部以下、２５重量部以下、２３重量部以下、２０重量部以下、１９重量部以下、１８重量部以下、更には１５重量部以下であってもよい。配合量が上記範囲にある粘着剤組成物（Ｉ）は、高められた弾性率を有する粘着シートの形成に適している。 The amount of the cross-linking agent (B) in the adhesive composition (I) is, for example, 5 parts by weight or more, 6 parts by weight or more, and 7 parts by weight with respect to 100 parts by weight of the (meth)acrylic polymer (A). Above, it may be 8 parts by weight or more, 9 parts by weight or more, 10 parts by weight or more, more than 10 parts by weight, or even 11 parts by weight or more. The upper limit of the compounding amount is, for example, 30 parts by weight or less, 28 parts by weight or less, 25 parts by weight or less, 23 parts by weight or less, 20 parts by weight or less, 19 parts by weight or less, 18 parts by weight or less, and further 15 parts by weight or less. may be The pressure-sensitive adhesive composition (I) having a blending amount within the above range is suitable for forming a pressure-sensitive adhesive sheet having an increased elastic modulus.
　本発明者らの検討によれば、配合量が上記範囲に達すると、粘着シートの形成時に架橋剤（Ｂ）同士が反応して、架橋剤（Ｂ）の自己重合体が形成されやすくなる。自己重合体の形成は、粘着シートの凝集力を高めることで、光学フィルムの寸法の変化を抑制しうる粘着シートの形成に寄与する。また、初期段階におけるゲル化の速度が抑えられた粘着剤組成物（Ｉ）では、形成された粘着シートにおける自己重合体の析出が抑制され、これにより、粘着シートの均一性を向上しうる。 According to the studies of the present inventors, when the blending amount reaches the above range, the cross-linking agent (B) reacts with each other during the formation of the pressure-sensitive adhesive sheet, facilitating the formation of a self-polymer of the cross-linking agent (B). The formation of the self-polymer increases the cohesive force of the adhesive sheet, thereby contributing to the formation of the adhesive sheet that can suppress the dimensional change of the optical film. In addition, in the pressure-sensitive adhesive composition (I) in which the speed of gelation in the initial stage is suppressed, precipitation of the self-polymer in the formed pressure-sensitive adhesive sheet is suppressed, thereby improving the uniformity of the pressure-sensitive adhesive sheet.
　粘着剤組成物（Ｉ）から形成された粘着シートは、（メタ）アクリル系ポリマー（Ａ）の架橋物と、架橋剤（Ｂ）の自己重合体との相互侵入網目（ＩＰＮ）構造を有していてもよい。ＩＰＮ構造は、粘着シートの耐久性の向上に適している。 The pressure-sensitive adhesive sheet formed from the pressure-sensitive adhesive composition (I) has an interpenetrating network (IPN) structure of a cross-linked product of the (meth)acrylic polymer (A) and a self-polymer of the cross-linking agent (B). may be The IPN structure is suitable for improving the durability of the adhesive sheet.
　架橋剤（Ｂ）の他の例は、過酸化物系架橋剤、エポキシ系架橋剤、イミン系架橋剤及び多官能性金属キレートである。ただし、架橋剤（Ｂ）は、好ましくはイソシアネート系である。イソシアネート系以外の架橋剤（Ｂ）を粘着剤組成物（Ｉ）が含む場合、その配合量の合計は、（メタ）アクリル系ポリマー（Ａ）１００重量部に対して、０．１～５重量部が好ましく、０．１～３重量部、０．１～２重量部及び０．１～１重量部の順に、より好ましい。粘着剤組成物（Ｉ）は、イソシアネート系以外の架橋剤（Ｂ）、例えばエポキシ系架橋剤、を含まなくてもよい。 Other examples of cross-linking agents (B) are peroxide-based cross-linking agents, epoxy-based cross-linking agents, imine-based cross-linking agents and polyfunctional metal chelates. However, the cross-linking agent (B) is preferably isocyanate-based. When the pressure-sensitive adhesive composition (I) contains a cross-linking agent (B) other than an isocyanate type, the total amount is 0.1 to 5 parts by weight with respect to 100 parts by weight of the (meth)acrylic polymer (A). parts are preferred, and 0.1 to 3 parts by weight, 0.1 to 2 parts by weight and 0.1 to 1 part by weight, in that order, are more preferred. The pressure-sensitive adhesive composition (I) may not contain a cross-linking agent (B) other than an isocyanate-based cross-linking agent, such as an epoxy-based cross-linking agent.
　［（メタ）アクリル系オリゴマー］
　粘着剤組成物（Ｉ）は、（メタ）アクリル系オリゴマー（Ｄ）を更に含んでいてもよい。 [(Meth) acrylic oligomer]
The pressure-sensitive adhesive composition (I) may further contain a (meth)acrylic oligomer (D).
　（メタ）アクリル系オリゴマー（Ｄ）は、重量平均分子量（Ｍｗ）が異なる以外は、上述した（メタ）アクリル系ポリマー（Ａ）と同様の組成を有することができる。（メタ）アクリル系オリゴマー（Ｄ）の重量平均分子量（Ｍｗ）は、例えば、１０００以上であり、２０００以上、３０００以上、更には４０００以上であってもよい。（メタ）アクリル系オリゴマーの重量平均分子量（Ｍｗ）の上限は、例えば、３００００以下であり、１５０００以下、１００００以下、更には７０００以下であってもよい。 The (meth)acrylic oligomer (D) can have the same composition as the (meth)acrylic polymer (A) described above, except that the weight average molecular weight (Mw) is different. The weight average molecular weight (Mw) of the (meth)acrylic oligomer (D) is, for example, 1000 or more, and may be 2000 or more, 3000 or more, or even 4000 or more. The upper limit of the weight average molecular weight (Mw) of the (meth)acrylic oligomer is, for example, 30,000 or less, and may be 15,000 or less, 10,000 or less, or even 7,000 or less.
　（メタ）アクリル系オリゴマー（Ｄ）は、例えば、以下の各単量体に由来する構成単位を１種又は２種以上有している：メチル（メタ）アクリレート、エチル（メタ）アクリレート、プロピル（メタ）アクリレート、イソプロピル（メタ）アクリレート、ブチル（メタ）アクリレート、イソブチル（メタ）アクリレート、ｓ－ブチル（メタ）アクリレート、ｔ－ブチル（メタ）アクリレート、ペンチル（メタ）アクリレート、イソペンチル（メタ）アクリレート、ヘキシル（メタ）アクリレート、２－エチルヘキシル（メタ）アクリレート、ヘプチル（メタ）アクリレート、オクチル（メタ）アクリレート、イソオクチル（メタ）アクリレート、ノニル（メタ）アクリレート、イソノニル（メタ）アクリレート、デシル（メタ）アクリレート、イソデシル（メタ）アクリレート、ウンデシル（メタ）アクリレート及びドデシル（メタ）アクリレート等のアルキル（メタ）アクリレート；シクロヘキシル（メタ）アクリレート、イソボルニル（メタ）アクリレート及びジシクロペンタニル（メタ）アクリレート等の（メタ）アクリル酸と脂環族アルコールとのエステル；フェニル（メタ）アクリレート、ベンジル（メタ）アクリレート等の芳香環含有（メタ）アクリレート；並びにテルペン化合物誘導体アルコールから得られる（メタ）アクリレート。 The (meth)acrylic oligomer (D) has, for example, one or more structural units derived from the following monomers: methyl (meth)acrylate, ethyl (meth)acrylate, propyl ( meth) acrylate, isopropyl (meth) acrylate, butyl (meth) acrylate, isobutyl (meth) acrylate, s-butyl (meth) acrylate, t-butyl (meth) acrylate, pentyl (meth) acrylate, isopentyl (meth) acrylate, hexyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, heptyl (meth)acrylate, octyl (meth)acrylate, isooctyl (meth)acrylate, nonyl (meth)acrylate, isononyl (meth)acrylate, decyl (meth)acrylate, Alkyl (meth)acrylates such as isodecyl (meth)acrylate, undecyl (meth)acrylate and dodecyl (meth)acrylate; (meth)acrylates such as cyclohexyl (meth)acrylate, isobornyl (meth)acrylate and dicyclopentanyl (meth)acrylate Esters of acrylic acid and alicyclic alcohols; aromatic ring-containing (meth)acrylates such as phenyl (meth)acrylate and benzyl (meth)acrylate; and (meth)acrylates obtained from terpene compound derivative alcohols.
　（メタ）アクリル系オリゴマー（Ｄ）は、比較的嵩高い構造を持つ（メタ）アクリル系単量体に由来する構成単位を有することが好ましい。この場合、粘着シートの接着性をより高めることができる。当該アクリル系単量体の例は、イソブチル（メタ）アクリレート及びｔ－ブチル（メタ）アクリレート等の分岐構造を持つアルキル基を有するアルキル（メタ）アクリレート；シクロヘキシル（メタ）アクリレート、イソボルニル（メタ）アクリレート及びジシクロペンタニル（メタ）アクリレート等の（メタ）アクリル酸と脂環式アルコールとのエステル；フェニル（メタ）アクリレート及びベンジル（メタ）アクリレート等の芳香環含有（メタ）アクリレートである。当該単量体は、環状構造を有することが好ましく、２以上の環状構造を有することがより好ましい。また、（メタ）アクリル系オリゴマー（Ｄ）の重合時、及び／又は粘着シートの形成時に紫外線の照射を実施する場合、重合及び／又は形成の進行が阻害され難いことから、上記単量体は不飽和結合を有さないことが好ましく、例えば、分岐構造を持つアルキル基を有するアルキル（メタ）アクリレート、（メタ）アクリル酸と脂環式アルコールとのエステルを使用できる。 The (meth)acrylic oligomer (D) preferably has structural units derived from a (meth)acrylic monomer having a relatively bulky structure. In this case, the adhesiveness of the adhesive sheet can be further enhanced. Examples of the acrylic monomer include alkyl (meth)acrylates having a branched alkyl group such as isobutyl (meth)acrylate and t-butyl (meth)acrylate; cyclohexyl (meth)acrylate and isobornyl (meth)acrylate. and esters of (meth)acrylic acid and alicyclic alcohols such as dicyclopentanyl (meth)acrylate; aromatic ring-containing (meth)acrylates such as phenyl (meth)acrylate and benzyl (meth)acrylate. The monomer preferably has a cyclic structure, more preferably two or more cyclic structures. In addition, when the (meth)acrylic oligomer (D) is polymerized and/or the pressure-sensitive adhesive sheet is formed when UV irradiation is performed, the progress of polymerization and/or formation is hardly inhibited. It preferably does not have an unsaturated bond, and for example, an alkyl (meth)acrylate having an alkyl group with a branched structure, or an ester of (meth)acrylic acid and an alicyclic alcohol can be used.
　（メタ）アクリル系オリゴマー（Ｄ）の具体例は、ブチルアクリレートとメチルアクリレートとアクリル酸との共重合体、シクロヘキシルメタクリレートとイソブチルメタクリレートとの共重合体、シクロヘキシルメタクリレートとイソボルニルメタクリレートとの共重合体、シクロヘキシルメタクリレートとアクリロイルモルホリンとの共重合体、シクロヘキシルメタクリレートとジエチルアクリルアミドとの共重合体、１－アダマンチルアクリレートとメチルメタクリレートとの共重合体、ジシクロペンタニルメタクリレートとイソボルニルメタクリレートとの共重合体、ジシクロペンタニルメタクリレート、シクロヘキシルメタクリレート、イソボルニルメタクリレート、イソボルニルアクリレート及びシクロペンタニルメタクリレートから選ばれる少なくとも１種とメチルメタクリレートとの共重合体、ジシクロペンタニルアクリレートの単独重合体、１－アダマンチルメタクリレートの単独重合体及び１－アダマンチルアクリレートの単独重合体である。 Specific examples of the (meth)acrylic oligomer (D) include a copolymer of butyl acrylate, methyl acrylate and acrylic acid, a copolymer of cyclohexyl methacrylate and isobutyl methacrylate, and a copolymer of cyclohexyl methacrylate and isobornyl methacrylate. Copolymers of cyclohexyl methacrylate and acryloylmorpholine, copolymers of cyclohexyl methacrylate and diethylacrylamide, copolymers of 1-adamantyl acrylate and methyl methacrylate, copolymers of dicyclopentanyl methacrylate and isobornyl methacrylate. Polymer, copolymer of methyl methacrylate and at least one selected from dicyclopentanyl methacrylate, cyclohexyl methacrylate, isobornyl methacrylate, isobornyl acrylate and cyclopentanyl methacrylate, homopolymer of dicyclopentanyl acrylate , a homopolymer of 1-adamantyl methacrylate and a homopolymer of 1-adamantyl acrylate.
　（メタ）アクリル系オリゴマー（Ｄ）の重合には、上述した（メタ）アクリル系ポリマー（Ａ）の重合方法を採用できる。 The polymerization method for the (meth)acrylic polymer (A) described above can be employed for the polymerization of the (meth)acrylic oligomer (D).
　粘着剤組成物（Ｉ）が（メタ）アクリル系オリゴマー（Ｄ）を含む場合、その配合量は、（メタ）アクリル系ポリマー（Ａ）１００重量部に対して、例えば７０重量部以下であり、５０重量部以下、更には４０重量部以下であってもよい。配合量の下限は、（メタ）アクリル系ポリマー（Ａ）１００重量部に対して、例えば１重量部以上であり、２重量部以上、更には３重量部以上であってもよい。粘着剤組成物（Ｉ）は、（メタ）アクリル系オリゴマー（Ｄ）を含まなくてもよい。 When the pressure-sensitive adhesive composition (I) contains the (meth)acrylic oligomer (D), the amount thereof is, for example, 70 parts by weight or less with respect to 100 parts by weight of the (meth)acrylic polymer (A), It may be 50 parts by weight or less, or even 40 parts by weight or less. The lower limit of the amount to be blended is, for example, 1 part by weight or more, 2 parts by weight or more, and may be 3 parts by weight or more with respect to 100 parts by weight of the (meth)acrylic polymer (A). The pressure-sensitive adhesive composition (I) may not contain the (meth)acrylic oligomer (D).
　［添加剤］
　粘着剤組成物（Ｉ）は、その他の添加剤を含んでいてもよい。添加剤の例は、シランカップリング剤、多官能アルコール、顔料及び染料等の着色剤、界面活性剤、可塑剤、粘着性付与剤、表面潤滑剤、レベリング剤、リワーク向上剤、軟化剤、酸化防止剤、老化防止剤、光安定剤、紫外線吸収剤、重合禁止剤、帯電防止剤（イオン性化合物であるアルカリ金属塩、イオン液体、イオン固体等）、無機充填材、有機充填材、金属粉等の粉体、粒子、箔状物である。添加剤は、(メタ）アクリル系ポリマー（Ａ）１００重量部に対して、例えば１０重量部以下、好ましくは５重量部以下、より好ましくは１重量部以下の範囲で配合できる。 [Additive]
The pressure-sensitive adhesive composition (I) may contain other additives. Examples of additives include silane coupling agents, polyfunctional alcohols, colorants such as pigments and dyes, surfactants, plasticizers, tackifiers, surface lubricants, leveling agents, rework improvers, softeners, oxidation Anti-aging agents, anti-aging agents, light stabilizers, ultraviolet absorbers, polymerization inhibitors, anti-static agents (ionic compounds such as alkali metal salts, ionic liquids, ionic solids, etc.), inorganic fillers, organic fillers, metal powders and other powders, particles, and foil-like materials. The additive can be blended in an amount of, for example, 10 parts by weight or less, preferably 5 parts by weight or less, and more preferably 1 part by weight or less per 100 parts by weight of the (meth)acrylic polymer (A).
　シランカップリング剤の例は、３－グリシドキシプロピルトリメトキシシラン、３－グリシドキシプロピルトリエトキシシラン、３－グリシドキシプロピルメチルジエトキシシラン及び２－（３，４－エポキシシクロヘキシル）エチルトリメトキシシラン等のエポキシ基含有シランカップリング剤；３－アミノプロピルトリメトキシシラン、Ｎ－２－（アミノエチル）－３－アミノプロピルメチルジメトキシシラン、３－トリエトキシシリル－Ｎ－（１，３－ジメチルブチリデン）プロピルアミン及びＮ－フェニル－γ－アミノプロピルトリメトキシシラン等のアミノ基含有シランカップリング剤；３－アクリロキシプロピルトリメトキシシラン及び３－メタクリロキシプロピルトリエトキシシラン等の（メタ）アクリル基含有シランカップリング剤；並びに３－イソシアネートプロピルトリエトキシシラン等のイソシアネート基含有シランカップリング剤である。 Examples of silane coupling agents are 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropyltriethoxysilane, 3-glycidoxypropylmethyldiethoxysilane and 2-(3,4-epoxycyclohexyl)ethyl Epoxy group-containing silane coupling agents such as trimethoxysilane; 3-aminopropyltrimethoxysilane, N-2-(aminoethyl)-3-aminopropylmethyldimethoxysilane, 3-triethoxysilyl-N-(1,3 -dimethylbutylidene)propylamine and amino group-containing silane coupling agents such as N-phenyl-γ-aminopropyltrimethoxysilane; ) acrylic group-containing silane coupling agents; and isocyanate group-containing silane coupling agents such as 3-isocyanatopropyltriethoxysilane.
　粘着剤組成物（Ｉ）がシランカップリング剤を含む場合、その配合量は、（メタ）アクリル系ポリマー（Ａ）１００重量部に対して、例えば５重量部以下であり、３重量部以下、１重量部以下、０．５重量部以下、０．２重量部以下、０．１重量部以下、更には０．０５重量部以下であってもよい。粘着剤組成物（Ｉ）は、シランカップリング剤を含まなくてもよい。 When the pressure-sensitive adhesive composition (I) contains a silane coupling agent, the amount is, for example, 5 parts by weight or less, 3 parts by weight or less, relative to 100 parts by weight of the (meth)acrylic polymer (A), It may be 1 part by weight or less, 0.5 parts by weight or less, 0.2 parts by weight or less, 0.1 parts by weight or less, or even 0.05 parts by weight or less. The adhesive composition (I) may not contain a silane coupling agent.
　粘着剤組成物（Ｉ）は、多官能アルコールを含んでいてもよい。多官能アルコールの分子量は、例えば２４０以下であり、２３０以下、２２０以下、２１０以下、２００以下、１９０以下、１８０以下、１７０以下、１６０以下、更には１５０以下であってもよい。分子量の下限は、例えば６０以上であり、８０以上、９０以上、更には１００以上であってもよい。 The adhesive composition (I) may contain a polyfunctional alcohol. The molecular weight of the polyfunctional alcohol is, for example, 240 or less, and may be 230 or less, 220 or less, 210 or less, 200 or less, 190 or less, 180 or less, 170 or less, 160 or less, or even 150 or less. The lower limit of the molecular weight is, for example, 60 or more, and may be 80 or more, 90 or more, or even 100 or more.
　多官能アルコールの例は、エチレングリコール及びプロピレングリコール等のアルキレングリコール及びその重合体；ジエチレングリコール等のエーテルグリコール及びその重合体；トリメチロールエタン；トリメチロールプロパン；グリセリン；並びにペンタエリスリトール及びソルビトール等の糖アルコールである。多官能アルコールは、好ましくはトリメチロールプロパン、グリセリン、並びにジエチレングリコール及びその重合体であり、より好ましくはトリメチロールプロパンである。 Examples of polyfunctional alcohols are alkylene glycols such as ethylene glycol and propylene glycol and their polymers; ether glycols such as diethylene glycol and their polymers; trimethylolethane; trimethylolpropane; is. Polyfunctional alcohols are preferably trimethylolpropane, glycerin, and diethylene glycol and polymers thereof, more preferably trimethylolpropane.
　多官能アルコールは３官能以上であってもよい。３官能の多官能アルコールの例は、トリメチロールプロパン及びグリセリンである。 The polyfunctional alcohol may be trifunctional or higher. Examples of trifunctional polyfunctional alcohols are trimethylolpropane and glycerin.
　多官能アルコールは、水酸基以外に、架橋剤（Ｂ）との反応性を有する反応基を有さなくてもよい。当該反応基は、例えば、アミノ基、カルボキシル基及びエポキシ基から選ばれる少なくとも１種であり、特にアミノ基、である。 The polyfunctional alcohol does not have to have a reactive group with reactivity with the cross-linking agent (B) other than the hydroxyl group. The reactive group is, for example, at least one selected from an amino group, a carboxyl group and an epoxy group, particularly an amino group.
　粘着剤組成物（Ｉ）における多官能アルコールの配合量は、（メタ）アクリル系ポリマー（Ａ）１００重量部に対して、例えば、０．５重量部以上２０重量部以下である。配合量の上限は、１５重量部以下、１０重量部以下、８重量部以下、５重量部以下、４重量部以下、更には３重量部以下であってもよい。 The blending amount of the polyfunctional alcohol in the adhesive composition (I) is, for example, 0.5 parts by weight or more and 20 parts by weight or less with respect to 100 parts by weight of the (meth)acrylic polymer (A). The upper limit of the blending amount may be 15 parts by weight or less, 10 parts by weight or less, 8 parts by weight or less, 5 parts by weight or less, 4 parts by weight or less, or even 3 parts by weight or less.
　粘着剤組成物（Ｉ）は、触媒等の架橋促進剤を含まなくてもよい。架橋促進剤の一例は、架橋剤（Ｂ）との反応性を有する反応基を有するポリエーテル、ポリエーテルポリオール、リン酸エステルである。反応基は、例えば、水酸基、アミノ基、カルボキシル基及びエポキシ基から選ばれる少なくとも１種であり、特に水酸基又はアミノ基、である。粘着剤組成物（Ｉ）は、アミノ基を有するポリエーテルポリオールを含まなくてもよく、水酸基を有するリン酸エステルを含まなくてもよい。 The adhesive composition (I) may not contain a cross-linking accelerator such as a catalyst. Examples of cross-linking accelerators are polyethers, polyether polyols, and phosphate esters having reactive groups reactive with the cross-linking agent (B). The reactive group is, for example, at least one selected from a hydroxyl group, an amino group, a carboxyl group and an epoxy group, particularly a hydroxyl group or an amino group. The pressure-sensitive adhesive composition (I) may not contain polyether polyols having amino groups, and may not contain phosphate esters having hydroxyl groups.
　粘着剤組成物（Ｉ）の型は、例えば、エマルション型、溶剤型（溶液型）、活性エネルギー線硬化型（光硬化型）、熱溶融型（ホットメルト型）である。耐久性により優れる粘着シートを形成できる観点からは、粘着剤組成物（Ｉ）は溶剤型であってもよい。溶剤型の粘着剤組成物（Ｉ）は、紫外線硬化剤等の光硬化剤を含まなくてもよい。 Types of the pressure-sensitive adhesive composition (I) are, for example, emulsion type, solvent type (solution type), active energy ray-curable type (light-curing type), and heat-melting type (hot-melt type). The pressure-sensitive adhesive composition (I) may be solvent-based from the viewpoint of forming a pressure-sensitive adhesive sheet with superior durability. The solvent-based pressure-sensitive adhesive composition (I) may not contain a photocuring agent such as an ultraviolet curing agent.
［粘着シート］
　本実施形態の粘着シートの一例を図１に示す。図１の粘着シート１は、粘着剤組成物（Ｉ）から形成されたものである。粘着シート１は、例えば、（メタ）アクリル系ポリマー（Ａ）の架橋物を含む。粘着シート１は、粘着剤組成物（Ｉ）から、以下のように形成できる。 [Adhesive sheet]
An example of the adhesive sheet of this embodiment is shown in FIG. The pressure-sensitive adhesive sheet 1 in FIG. 1 is formed from the pressure-sensitive adhesive composition (I). The adhesive sheet 1 contains, for example, a crosslinked product of (meth)acrylic polymer (A). The adhesive sheet 1 can be formed from the adhesive composition (I) as follows.
　溶剤型については、例えば、粘着剤組成物（Ｉ）又は粘着剤組成物（Ｉ）と溶剤との混合物を基材フィルムに塗布して塗布膜を形成し、形成された塗布膜を乾燥して粘着シート１を形成する。乾燥時の熱により粘着剤組成物（Ｉ）は熱硬化する。活性エネルギー線硬化型（光硬化型）については、例えば、重合により（メタ）アクリル系ポリマー（Ａ）となる単量体（群）、架橋剤（Ｂ）、並びに必要に応じて、単量体（群）の部分重合物、重合開始剤、オリゴマー（Ｄ）、添加剤及び溶剤等の混合物を基材フィルムに塗布し、活性エネルギー線を照射して粘着シート１を形成する。活性エネルギー線の照射前に、乾燥により溶剤を除去してもよい。基材フィルムは、塗布面に剥離処理がなされたフィルム（剥離フィルム）であってもよい。 For the solvent type, for example, the pressure-sensitive adhesive composition (I) or a mixture of the pressure-sensitive adhesive composition (I) and a solvent is applied to a base film to form a coating film, and the formed coating film is dried. An adhesive sheet 1 is formed. The pressure-sensitive adhesive composition (I) is thermally cured by heat during drying. For the active energy ray-curable type (photocurable type), for example, a monomer (group) that becomes a (meth)acrylic polymer (A) by polymerization, a cross-linking agent (B), and, if necessary, a monomer A mixture of the partial polymer (group), polymerization initiator, oligomer (D), additive, solvent, etc. is applied to a base film and irradiated with active energy rays to form a pressure-sensitive adhesive sheet 1 . The solvent may be removed by drying before irradiation with active energy rays. The base film may be a film (release film) whose coating surface has been subjected to release treatment.
　基材フィルム上に形成された粘着シート１は、任意の層に転写できる。また、基材フィルムは光学フィルムであってもよく、この場合、粘着シート１と光学フィルムとを含む光学積層体が得られる。 The adhesive sheet 1 formed on the base film can be transferred to any layer. Moreover, the base film may be an optical film, and in this case, an optical laminate including the adhesive sheet 1 and the optical film is obtained.
　基材フィルムへの塗布には、公知の方法を採用できる。塗布は、例えば、ロールコート、キスロールコート、グラビアコート、リバースコート、ロールブラッシュ、スプレーコート、ディップロールコート、バーコート、ナイフコート、エアーナイフコート、カーテンコート、リップコート、ダイコーター等による押出しコートにより実施できる。 A known method can be adopted for application to the base film. Coating is, for example, 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, extrusion coating using a die coater, or the like. can be implemented by
　溶剤型について、塗布後の乾燥温度は、例えば、４０～２００℃である。乾燥温度は、１６０℃以下、１５０℃以下、１３０℃以下、１２０℃以下、更には１００℃以下であってもよい。乾燥温度を１３０℃以下、１２０℃以下、更には１００℃以下とすることにより、耐久性により優れる粘着シート１が得られる。換言すれば、粘着剤組成物（Ｉ）の塗布膜を１３０℃以下、１２０℃以下、更には１００℃以下、の温度で乾燥させて粘着シート１を得てもよい。乾燥時間は、例えば、５秒～２０分であり、５秒～１０分、更には１０秒～５分であってもよい。活性エネルギー線硬化型について、塗布後の乾燥を行う場合の乾燥温度及び乾燥時間は、上記範囲であってもよい。 For the solvent type, the drying temperature after coating is, for example, 40 to 200°C. The drying temperature may be 160° C. or lower, 150° C. or lower, 130° C. or lower, 120° C. or lower, or even 100° C. or lower. By setting the drying temperature to 130° C. or lower, 120° C. or lower, or further 100° C. or lower, the adhesive sheet 1 having excellent durability can be obtained. In other words, the adhesive sheet 1 may be obtained by drying the coating film of the adhesive composition (I) at a temperature of 130° C. or lower, 120° C. or lower, or further 100° C. or lower. The drying time is, for example, 5 seconds to 20 minutes, and may be 5 seconds to 10 minutes, or even 10 seconds to 5 minutes. For the active energy ray-curable type, the drying temperature and drying time when drying after coating may be within the above ranges.
　基材フィルムに塗布する組成物及び混合物は、取り扱い及び塗工に適した粘度を有することが好ましい。このため、活性エネルギー線硬化型については、塗布する混合物は、単量体（群）の部分重合物を含むことが好ましい。 The composition and mixture to be applied to the base film preferably have a viscosity suitable for handling and coating. Therefore, for the active energy ray-curable type, the mixture to be applied preferably contains a partial polymer of the monomer (group).
　剥離フィルムの一例では、シリコーン化合物により塗布面の剥離処理がなされている。 In one example of the release film, the coated surface is subjected to release treatment with a silicone compound.
　粘着シート１の厚さは、例えば、１～２００μｍであり、５～１５０μｍ、更には１０～１００μｍであってもよい。 The thickness of the adhesive sheet 1 is, for example, 1 to 200 μm, 5 to 150 μm, and may be 10 to 100 μm.
　粘着シート１の貯蔵弾性率Ｇ’（２５℃）は、例えば０．１５ＭＰａ以上であり、０．２ＭＰａ以上、０．２５ＭＰａ以上、０．３ＭＰａ以上、０．４ＭＰａ以上、０．５ＭＰａ以上、０．６ＭＰａ以上、０．７ＭＰａ以上、０．８ＭＰａ以上、０．９ＭＰａ以上、１．０ＭＰａ以上、更には１．１ＭＰａ以上であってもよい。貯蔵弾性率Ｇ’（２５℃）の上限は、例えば５ＭＰａ以下であり、３．０ＭＰａ以下、２．５ＭＰａ以下、更には２．０ＭＰａ以下であってもよい。貯蔵弾性率Ｇ’が上記範囲にある粘着シート１は、光学フィルムの寸法の変化を抑えることに、より適している。 The storage elastic modulus G′ (25° C.) of the adhesive sheet 1 is, for example, 0.15 MPa or higher, 0.2 MPa or higher, 0.25 MPa or higher, 0.3 MPa or higher, 0.4 MPa or higher, 0.5 MPa or higher, 0.5 MPa or higher, and 0.2 MPa or higher. It may be 6 MPa or more, 0.7 MPa or more, 0.8 MPa or more, 0.9 MPa or more, 1.0 MPa or more, or even 1.1 MPa or more. The upper limit of the storage modulus G' (25°C) is, for example, 5 MPa or less, and may be 3.0 MPa or less, 2.5 MPa or less, or even 2.0 MPa or less. The pressure-sensitive adhesive sheet 1 having a storage elastic modulus G' within the above range is more suitable for suppressing changes in the dimensions of the optical film.
　粘着シート１の貯蔵弾性率（２５℃）は、以下の方法により評価できる。最初に、粘着シート１を構成する材料でできた測定用サンプルを準備する。測定用サンプルの形状は、円盤状である。測定用サンプルは、底面の直径が８ｍｍであり、厚さが２ｍｍである。測定用サンプルは、複数の粘着シート１が積層された積層体を円盤状に打ち抜いたものであってもよい。次に、測定用サンプルについて動的粘弾性測定を行う。動的粘弾性測定には、例えば、TA Instruments製、ＡＲＥＳ－Ｇ２を用いることができる。動的粘弾性測定の結果から、粘着シート１の２５℃における貯蔵弾性率Ｇ’を特定することができる。なお、動的粘弾性測定の条件は、以下のとおりである。
・測定条件
　周波数：１Ｈｚ
　変形モード：ねじり
　測定温度：－７０℃～１５０℃
　昇温速度：５℃／分 The storage elastic modulus (25° C.) of PSA Sheet 1 can be evaluated by the following method. First, a sample for measurement made of the material constituting the adhesive sheet 1 is prepared. The shape of the measurement sample is disc-shaped. The measurement sample has a bottom diameter of 8 mm and a thickness of 2 mm. A sample for measurement may be obtained by punching a disc-shaped laminate from a laminate in which a plurality of pressure-sensitive adhesive sheets 1 are laminated. Next, a dynamic viscoelasticity measurement is performed on the measurement sample. For dynamic viscoelasticity measurement, for example, ARES-G2 manufactured by TA Instruments can be used. From the results of the dynamic viscoelasticity measurement, the storage elastic modulus G' of the pressure-sensitive adhesive sheet 1 at 25°C can be specified. The conditions for the dynamic viscoelasticity measurement are as follows.
・Measurement conditions Frequency: 1Hz
Deformation mode: Torsion Measurement temperature: -70°C to 150°C
Heating rate: 5°C/min
　粘着シート１は、例えば、光学用途に使用できる。粘着シート１は、光学積層体及び／又は画像表示装置に使用してもよい。粘着シート１は、例えば、狭額縁化された画像表示装置や比較的大きな画面サイズを有する画像表示装置等、光学フィルムについて寸法の変化の抑制が特に求められる画像表示装置への使用に適している。これらの画像表示装置への使用により、例えば、光学積層体に含まれるフィルムの剥がれが抑制される。 The adhesive sheet 1 can be used for optical applications, for example. The pressure-sensitive adhesive sheet 1 may be used for optical laminates and/or image display devices. The pressure-sensitive adhesive sheet 1 is suitable for use in image display devices, such as an image display device with a narrow frame and an image display device with a relatively large screen size, for which suppression of dimensional change in the optical film is particularly required. . By using these in image display devices, for example, peeling of the film included in the optical layered body is suppressed.
［光学積層体］
　本実施形態の光学積層体の一例を図２に示す。図２の光学積層体１０Ａは、粘着シート１と光学フィルム２とを含む。粘着シート１と光学フィルム２とは互いに積層されている。光学積層体１０Ａは、粘着シート付き光学フィルムとして使用できる。 [Optical laminate]
An example of the optical laminate of this embodiment is shown in FIG. The optical layered body 10A of FIG. 2 includes an adhesive sheet 1 and an optical film 2. As shown in FIG. The adhesive sheet 1 and the optical film 2 are laminated together. 10 A of optical laminated bodies can be used as an optical film with an adhesive sheet.
　光学フィルム２の例は、偏光板、位相差フィルム、並びに偏光板及び／又は位相差フィルムを含む積層フィルムである。ただし、光学フィルム２は、上記例に限定されない。光学フィルム２は、ガラス製のフィルムを含んでいてもよい。 Examples of the optical film 2 are a polarizing plate, a retardation film, and a laminated film containing a polarizing plate and/or a retardation film. However, the optical film 2 is not limited to the above examples. The optical film 2 may contain a film made of glass.
　偏光板は、偏光子を含む。偏光子の少なくとも一方の面に偏光子保護フィルムが接合されていてもよい。偏光子と偏光子保護フィルムとの接合には、任意の粘着剤や接着剤を使用できる。粘着シート１を接合に使用してもよい。偏光子は、典型的には、空中延伸（乾式延伸）、ホウ酸水中延伸等の延伸によってヨウ素が配向されたポリビニルアルコール（ＰＶＡ）フィルムである。 A polarizing plate includes a polarizer. A polarizer protective film may be bonded to at least one surface of the polarizer. Any pressure-sensitive adhesive or adhesive can be used for joining the polarizer and the polarizer protective film. The adhesive sheet 1 may be used for bonding. A polarizer is typically a polyvinyl alcohol (PVA) film in which iodine is oriented by stretching such as stretching in air (dry stretching) or stretching in boric acid solution.
　位相差フィルムは、面内方向及び／又は厚さ方向に複屈折を有するフィルムである。位相差フィルムは、例えば、延伸された樹脂フィルム、液晶材料を配向及び固定化させたフィルムである。 A retardation film is a film that has birefringence in the in-plane direction and/or the thickness direction. A retardation film is, for example, a stretched resin film or a film in which a liquid crystal material is oriented and fixed.
　位相差フィルムは、λ／４板、λ／２板、反射防止用位相差フィルム（例えば特開２０１２－１３３３０３号公報の段落０２２１，０２２２，０２２８参照）、視野角補償用位相差フィルム（例えば特開２０１２－１３３３０３号公報の段落０２２５，０２２６参照）、視野角補償用の傾斜配向位相差フィルム（例えば特開２０１２－１３３０３号公報の段落０２２７参照）であってもよい。位相差フィルムは、面内方向及び／又は厚さ方向に複屈折を有する限り、上記例に限定されない。位相差フィルムの位相差値、配置角度、３次元複屈折率、単層であるか多層であるか等についても限定されない。位相差フィルムには、公知のフィルムを使用可能である。 The retardation film includes a λ / 4 plate, a λ / 2 plate, an antireflection retardation film (see, for example, paragraphs 0221, 0222, 0228 of JP-A-2012-133303), a viewing angle compensation retardation film (for example, JP-A-2012-133303, paragraphs 0225 and 0226), obliquely oriented retardation film for viewing angle compensation (eg, JP-A-2012-13303, paragraph 0227). The retardation film is not limited to the above examples as long as it has birefringence in the in-plane direction and/or the thickness direction. The retardation value of the retardation film, the arrangement angle, the three-dimensional birefringence, whether it is a single layer or a multilayer, and the like are not limited. A known film can be used as the retardation film.
　光学フィルム２の厚さは、例えば１～２００μｍである。偏光板である光学フィルム２の厚さは、例えば１～１５０μｍであり、１００μｍ以下、７５μｍ以下、５０μｍ以下、２０μｍ以下、更には１５μｍ以下であってもよい。厚さの下限は、１０μｍ以上、２０μｍ以上、５０μｍ以上、７５μｍ以上、更には１００μｍ以上であってもよい。 The thickness of the optical film 2 is, for example, 1 to 200 μm. The thickness of the optical film 2, which is a polarizing plate, is, for example, 1 to 150 μm, and may be 100 μm or less, 75 μm or less, 50 μm or less, 20 μm or less, or even 15 μm or less. The lower limit of the thickness may be 10 μm or more, 20 μm or more, 50 μm or more, 75 μm or more, or even 100 μm or more.
　光学フィルム２は、単層であっても、２以上の層から構成される積層フィルムであってもよい。光学フィルム２が積層フィルムである場合、各層の接合に粘着シート１を使用してもよい。 The optical film 2 may be a single layer or a laminated film composed of two or more layers. When the optical film 2 is a laminated film, the adhesive sheet 1 may be used for joining the layers.
　本実施形態の光学積層体の別の一例を図３に示す。図３の光学積層体１０Ｂは、はく離ライナー３、粘着シート１及び光学フィルム２がこの順に積層された積層構造を有する。光学積層体１０Ｂは、はく離ライナー３を剥離することで、粘着シート付き光学フィルムとして使用できる。 Another example of the optical laminate of this embodiment is shown in FIG. The optical layered body 10B of FIG. 3 has a layered structure in which a release liner 3, an adhesive sheet 1 and an optical film 2 are layered in this order. By peeling off the release liner 3, the optical laminate 10B can be used as an optical film with an adhesive sheet.
　はく離ライナー３は、典型的には、樹脂フィルムである。はく離ライナー３を構成する樹脂の例は、ポリエチレンテレフタレート（ＰＥＴ）等のポリエステル、ポリエチレン及びポリプロピレン等のポリオレフィン、ポリカーボネート、アクリル、ポリスチレン、ポリアミド、並びにポリイミドである。はく離ライナー３における粘着シート１と接する面には、剥離処理がなされていてもよい。剥離処理は、例えばシリコーン化合物による処理である。ただし、はく離ライナー３は上記例に限定されない。はく離ライナー３は、光学積層体１０Ｂの使用時、例えば画像形成層への貼付時、には剥離される。 The release liner 3 is typically a resin film. Examples of resins that make up the release liner 3 are polyesters such as polyethylene terephthalate (PET), polyolefins such as polyethylene and polypropylene, polycarbonates, acrylics, polystyrenes, polyamides, and polyimides. The surface of the release liner 3 that contacts the adhesive sheet 1 may be subjected to a release treatment. The release treatment is, for example, treatment with a silicone compound. However, the release liner 3 is not limited to the above example. The release liner 3 is peeled off when the optical layered body 10B is used, for example, when attached to the image forming layer.
　本実施形態の光学積層体の別の一例を図４に示す。図４の光学積層体１０Ｃは、はく離ライナー３、粘着シート１、位相差フィルム２Ａ、層間粘着剤４及び偏光板２Ｂがこの順に積層された積層構造を有する。光学積層体１０Ｃは、はく離ライナー３を剥離した後、例えば画像形成層に貼付して使用できる。 Another example of the optical laminate of this embodiment is shown in FIG. The optical laminate 10C of FIG. 4 has a laminate structure in which a release liner 3, an adhesive sheet 1, a retardation film 2A, an interlayer adhesive 4 and a polarizing plate 2B are laminated in this order. After peeling off the release liner 3, the optical layered body 10C can be used by attaching it to, for example, an image forming layer.
　層間粘着剤４には、公知の粘着剤を使用できる。粘着シート１を層間粘着剤４に使用してもよい。 A known adhesive can be used for the interlayer adhesive 4 . The adhesive sheet 1 may be used as the interlayer adhesive 4 .
　本実施形態の光学積層体の別の一例を図５に示す。図５の光学積層体１０Ｄは、はく離ライナー３、粘着シート１、位相差フィルム２Ａ、層間粘着剤４、偏光板２Ｂ及び保護フィルム５がこの順に積層された積層構造を有する。光学積層体１０Ｄは、はく離ライナーを剥離した後、例えば画像形成層に貼付して使用できる。 Another example of the optical laminate of this embodiment is shown in FIG. The optical laminate 10D of FIG. 5 has a laminate structure in which a release liner 3, an adhesive sheet 1, a retardation film 2A, an interlayer adhesive 4, a polarizing plate 2B and a protective film 5 are laminated in this order. After peeling off the release liner, the optical layered body 10D can be used, for example, by attaching it to the image forming layer.
　保護フィルム５は、光学積層体１０Ｄの流通及び保管時、並びに光学積層体１０Ｄを画像表示装置に組み込んだ状態において、最外層である光学フィルム２（偏光板２Ｂ）を保護する機能を有する。また、画像表示装置に組み込んだ状態において、外部空間へのウィンドウとして機能する保護フィルム５であってもよい。保護フィルム５は、典型的には、樹脂フィルムである。保護フィルム５を構成する樹脂は、例えば、ＰＥＴ等のポリエステル、ポリエチレン及びポリプロピレン等のポリオレフィン、アクリル、シクロオレフィン、ポリイミド、並びにポリアミドであり、ポリエステルが好ましい。ただし、保護フィルム５は上記例に限定されない。保護フィルム５は、ガラス製のフィルム、又はガラス製のフィルムを含む積層フィルムであってもよい。保護フィルム５には、アンチグレア、反射防止、帯電防止等の表面処理が施されていてもよい。 The protective film 5 has a function of protecting the outermost optical film 2 (polarizing plate 2B) during distribution and storage of the optical layered body 10D and when the optical layered body 10D is incorporated in an image display device. Moreover, it may be the protective film 5 that functions as a window to an external space when incorporated in the image display device. Protective film 5 is typically a resin film. The resin constituting the protective film 5 is, for example, polyester such as PET, polyolefin such as polyethylene and polypropylene, acrylic, cycloolefin, polyimide, and polyamide, preferably polyester. However, the protective film 5 is not limited to the above examples. The protective film 5 may be a glass film or a laminated film containing a glass film. The protective film 5 may be subjected to surface treatments such as antiglare, antireflection, and antistatic.
　保護フィルム５は、任意の粘着剤によって光学フィルム２に接合されていてもよい。粘着シート１による接合も可能である。 The protective film 5 may be bonded to the optical film 2 with any adhesive. Bonding with the adhesive sheet 1 is also possible.
　本実施形態の光学積層体は、例えば、帯状の光学積層体を巻回した巻回体として、あるいは枚葉状の光学積層体として、流通及び保管が可能である。 The optical layered body of the present embodiment can be distributed and stored, for example, as a wound body in which a strip-shaped optical layered body is wound, or as a sheet-shaped optical layered body.
　本実施形態の光学積層体は、典型的には、画像表示装置に用いられる。画像表示装置は、例えば、液晶ディスプレイ、有機ＥＬディスプレイ及び無機ＥＬディスプレイ等のＥＬディスプレイである。 The optical laminate of this embodiment is typically used in an image display device. The image display device is, for example, an EL display such as a liquid crystal display, an organic EL display and an inorganic EL display.
［画像表示装置］
　本実施形態の画像表示装置の一例を図６に示す。図６の画像表示装置１１は、基板７、画像形成層（例えば有機ＥＬ層又は液晶層）６、粘着シート１、位相差フィルム２Ａ、層間粘着剤４、偏光板２Ｂ及び保護フィルム５がこの順に積層された積層構造を有している。画像表示装置１１は、図２～５の光学積層体１０Ａ，１０Ｂ，１０Ｃ，１０Ｄを有している（ただし、はく離ライナー３を除く）。基板７及び画像形成層６は、公知の画像表示装置が備える基板及び画像形成層と、それぞれ同様の構成を有していればよい。 [Image display device]
An example of the image display device of this embodiment is shown in FIG. The image display device 11 in FIG. 6 includes a substrate 7, an image forming layer (for example, an organic EL layer or a liquid crystal layer) 6, an adhesive sheet 1, a retardation film 2A, an interlayer adhesive 4, a polarizing plate 2B and a protective film 5 in this order. It has a laminated structure. The image display device 11 has the optical laminates 10A, 10B, 10C, and 10D of FIGS. 2 to 5 (excluding the release liner 3). The substrate 7 and the image forming layer 6 may have the same configurations as those of the substrate and the image forming layer provided in a known image display device.
　図６の画像表示装置１１は、有機ＥＬディスプレイであってもよく、液晶ディスプレイであってもよい。ただし、画像表示装置１１はこの例に限定されない。画像表示装置１１は、エレクトロルミネッセンス（ＥＬ）ディスプレイ、プラズマディスプレイ（ＰＤ）、電界放出ディスプレイ（ＦＥＤ：Field Emission Display）等であってもよい。画像表示装置１１は、家電用途、車載用途、パブリックインフォメーションディスプレイ（ＰＩＤ）用途等に用いてもよい。 The image display device 11 in FIG. 6 may be an organic EL display or a liquid crystal display. However, the image display device 11 is not limited to this example. The image display device 11 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 11 may be used for home appliance use, vehicle use, public information display (PID) use, and the like.
　本実施形態の画像表示装置は、本実施形態の光学積層体を備える限り、任意の構成を有しうる。 The image display device of this embodiment can have any configuration as long as it includes the optical layered body of this embodiment.
　以下、実施例により、本発明を更に詳細に説明する。本発明は、以下に示す実施例に限定されない。 The present invention will be described in more detail below with reference to examples. The invention is not limited to the examples shown below.
　最初に、実施例及び比較例において作製した（メタ）アクリル系ポリマー及び粘着シートの評価方法を示す。 First, evaluation methods for the (meth)acrylic polymers and pressure-sensitive adhesive sheets produced in Examples and Comparative Examples are shown.
　［重量平均分子量（Ｍｗ）］
　（メタ）アクリル系ポリマーの重量平均分子量（Ｍｗ）は、ＧＰＣにより、以下の条件にて評価した。
　・分析装置：Ｗａｔｅｒｓ製、Ａｃｑｕｉｔｙ　ＡＰＣ
　・カラム：東ソー製、Ｇ７０００ＨＸＬ＋ＧＭＨＸＬ＋ＧＭＨＸＬ
　・カラム温度：４０℃
　・溶離液：テトラヒドロフラン（酸添加）
　・流速：０．８ｍＬ／分
　・注入量：１００μＬ
　・検出器：示差屈折計（ＲＩ）
　・標準試料：Ａｇｉｌｅｎｔ製、ポリスチレン（ＰＳ） [Weight average molecular weight (Mw)]
The weight average molecular weight (Mw) of the (meth)acrylic polymer was evaluated by GPC under the following conditions.
・ Analyzer: Acquity APC manufactured by Waters
・Column: G7000HXL+GMHXL+GMHXL manufactured by Tosoh
・Column temperature: 40°C
・Eluent: tetrahydrofuran (acid added)
・Flow rate: 0.8 mL/min ・Injection volume: 100 μL
・Detector: Differential refractometer (RI)
・ Standard sample: Polystyrene (PS) manufactured by Agilent
　［ゲル分率Ｇ0、Ｇ2h、Ｇ24h、Ｇ7d］
　粘着剤組成物から粘着シートを形成したときのゲル分率Ｇ0、Ｇ2h、Ｇ24h、Ｇ7dは、上述の方法により評価した。ただし、基材フィルムには、ＰＥＴフィルムを使用した。基材フィルムへの粘着剤組成物の塗布は、コーターを用いて常温（２５℃）で実施した。基材フィルム上に形成する塗布膜の厚さは、乾燥後の粘着シートの厚さが５０μｍとなるように調整した。粘着シートを形成した時点Ｔ0を定める際の塗布膜の乾燥条件は、９０℃及び１００秒間とした。乾燥後の自然冷却及び時点Ｔ0以降の粘着シートの放置の雰囲気は、２５℃及び５０％ＲＨとした。乾燥後の塗布膜の温度が自然冷却によって常温に戻った（換言すれば、粘着シートとして使用できる状態になった）ことは、当該膜の表面温度を赤外線放射温度計により測定することで確認した。ゲル分率Ｇ0の評価は、時点Ｔ0から５分経過後の粘着シートに対して実施した。 [Gel fraction G 0 , G 2h , G 24h , G 7d ]
The gel fractions G 0 , G 2h , G 24h , and G 7d when pressure-sensitive adhesive sheets were formed from the pressure-sensitive adhesive compositions were evaluated by the methods described above. However, a PET film was used as the base film. Application of the pressure-sensitive adhesive composition to the base film was carried out at room temperature (25°C) using a coater. The thickness of the coating film formed on the base film was adjusted so that the thickness of the adhesive sheet after drying was 50 μm. The drying conditions for the coating film when determining the time T 0 at which the pressure-sensitive adhesive sheet was formed were 90° C. and 100 seconds. The atmosphere for natural cooling after drying and for leaving the PSA sheet after time T 0 was 25° C. and 50% RH. It was confirmed by measuring the surface temperature of the film with an infrared radiation thermometer that the temperature of the coated film after drying returned to normal temperature due to natural cooling (in other words, the film was ready for use as an adhesive sheet). . Evaluation of the gel fraction G 0 was performed on the pressure-sensitive adhesive sheet 5 minutes after the time T 0 .
　［貯蔵弾性率Ｇ’（２５℃）］
　粘着シートの貯蔵弾性率Ｇ’（２５℃）は、上述の方法により評価した。ただし、測定用サンプルは、作製した粘着シート（時点Ｔ0から７日間以上経過したもの）を重ねて得た積層体を円盤状に打ち抜いて準備した。測定用サンプルに対する動的粘弾性測定には、TA Instruments製、ＡＲＥＳ－Ｇ２を用いた。 [Storage elastic modulus G' (25°C)]
The storage elastic modulus G' (25°C) of the pressure-sensitive adhesive sheet was evaluated by the method described above. However, the sample for measurement was prepared by punching out a laminate obtained by stacking the produced pressure-sensitive adhesive sheets (7 days or more after time T 0 ) into a disc shape. ARES-G2 manufactured by TA Instruments was used for the dynamic viscoelasticity measurement of the measurement sample.
　［加湿耐久性］
　粘着シートの加湿耐久性（耐久性の加速試験に相当）は、以下の方法により評価した。最初に、実施例及び比較例で作製した各粘着シート（時点Ｔ0から７日間以上経過したもの）を一方の露出面に備える粘着シート付き円偏光板を形成した。次に、上記粘着シートを介して、ガラス板（コーニング製、イーグルＸＧ）の表面に円偏光板を固定した。円偏光板の固定は、２３℃及び５０％ＲＨの雰囲気で実施した。次に、５０℃及び５気圧（絶対圧）のオートクレーブにて１５分処理した後、２３℃に冷えるまで放置して、ガラス板への円偏光板の接合を安定させた後、６０℃及び９５％ＲＨの加熱加湿雰囲気に５００時間放置した。放置後、２３℃及び５０％ＲＨの雰囲気に戻し、ガラス板からの円偏光板の剥がれや、ガラス板と円偏光板との間に発泡が生じていないかを目視により確認して、以下のように、加湿耐久性を評価した。
　Ａ：発泡や剥がれ等の外観上の変化がみられない。
　Ｂ：端部において、単独の剥がれ又は発泡がわずかにみられるが、実用上、問題ない範囲にある。
　Ｃ：端部において、連続した剥がれ又は発泡がわずかにみられるが、実用上、問題ない範囲にある。
　Ｄ：端部に著しい剥がれ又は発泡がみられ、実用上、問題がある。 [Humidification durability]
Humidification durability (corresponding to an accelerated durability test) of the PSA sheet was evaluated by the following method. First, a pressure-sensitive adhesive sheet-attached circularly polarizing plate having one exposed surface provided with each pressure-sensitive adhesive sheet produced in Examples and Comparative Examples (7 days or more after time T 0 ) was formed. Next, a circularly polarizing plate was fixed to the surface of a glass plate (Eagle XG manufactured by Corning) via the adhesive sheet. Fixing of the circularly polarizing plate was performed in an atmosphere of 23° C. and 50% RH. Next, after treatment in an autoclave at 50 ° C. and 5 atmospheres (absolute pressure) for 15 minutes, it was left to stand until it cooled to 23 ° C., and after stabilizing the bonding of the circularly polarizing plate to the glass plate, it was heated at 60 ° C. and 95 ° C. It was left for 500 hours in a heated and humidified atmosphere of % RH. After standing, the atmosphere was returned to 23° C. and 50% RH, and the circularly polarizing plate was visually checked for peeling from the glass plate and bubbles between the glass plate and the circularly polarizing plate. Humidification durability was evaluated as follows.
A: No change in appearance such as foaming or peeling is observed.
B: Single peeling or foaming is slightly observed at the edge, but within a practically acceptable range.
C: Slight continuous peeling or foaming is observed at the edge, but within a practically acceptable range.
D: Significant peeling or foaming is observed at the edge, which is problematic in practice.
　以下、加湿耐久性の評価に使用した粘着シート付き円偏光板の形成方法を示す。 Below, the method of forming the circularly polarizing plate with the adhesive sheet used to evaluate the humidification durability is shown.
　＜偏光板Ｐ１の作製＞
　（偏光子の作製）
　長尺状のポリビニルアルコール（ＰＶＡ）系樹脂フィルム（クラレ製、製品名「ＰＥ３０００」、厚さ３０μｍ）を、ロール延伸機を用いて長手方向に一軸延伸（総延伸倍率５．９倍）すると同時に、上記樹脂フィルムに対して膨潤、染色、架橋、洗浄及び乾燥の各処理を順に施して、厚さ１２μｍの偏光子を作製した。膨潤処理では、上記樹脂フィルムを２０℃の純水で処理しながら２．２倍延伸した。染色処理では、ヨウ素及びヨウ化カリウムを重量比１：７で含有する３０℃の水溶液で処理しながら、上記樹脂フィルムを１．４倍延伸した。水溶液中のヨウ素濃度は、作製する偏光子の単体透過率が４５．０％となるように調整された。架橋処理には、２段階処理を採用した。１段階目の架橋処理では、ホウ酸及びヨウ化カリウムを溶解させた４０℃の水溶液で処理しながら、上記樹脂フィルムを１．２倍延伸した。１段階目の架橋処理に用いた水溶液におけるホウ酸の含有率は５．０重量％、ヨウ化カリウムの含有率は３．０重量％とした。２段階目の架橋処理では、ホウ酸及びヨウ化カリウムを溶解させた６５℃の水溶液で処理しながら、上記樹脂フィルムを１．６倍延伸した。２段階目の架橋処理に用いた水溶液におけるホウ酸の含有率は４．３重量％、ヨウ化カリウムの含有率は５．０重量％とした。洗浄処理には、２０℃のヨウ化カリウム水溶液を用いた。洗浄処理に用いた水溶液におけるヨウ化カリウムの含有率は２．６重量％とした。乾燥処理は、７０℃及び５分間の乾燥条件で実施した。 <Preparation of polarizing plate P1>
(Production of polarizer)
A long polyvinyl alcohol (PVA) resin film (manufactured by Kuraray, product name “PE3000”, thickness 30 μm) is uniaxially stretched in the longitudinal direction using a roll stretching machine (total stretching ratio 5.9 times) at the same time. , swelling, dyeing, cross-linking, washing and drying were sequentially performed on the resin film to prepare a polarizer having a thickness of 12 μm. In the swelling treatment, the resin film was stretched 2.2 times while being treated with pure water at 20°C. In the dyeing treatment, the resin film was stretched 1.4 times while being treated with an aqueous solution containing iodine and potassium iodide at a weight ratio of 1:7 at 30°C. The iodine concentration in the aqueous solution was adjusted so that the single transmittance of the polarizer to be produced was 45.0%. A two-step process was employed for the cross-linking treatment. In the first-stage cross-linking treatment, the resin film was stretched 1.2 times while being treated with an aqueous solution of boric acid and potassium iodide at 40°C. The content of boric acid in the aqueous solution used for the first-stage cross-linking treatment was 5.0% by weight, and the content of potassium iodide was 3.0% by weight. In the second-stage cross-linking treatment, the resin film was stretched 1.6 times while being treated with an aqueous solution of boric acid and potassium iodide at 65°C. The content of boric acid in the aqueous solution used in the second-stage cross-linking treatment was 4.3% by weight, and the content of potassium iodide was 5.0% by weight. A potassium iodide aqueous solution at 20° C. was used for the cleaning treatment. The content of potassium iodide in the aqueous solution used for the cleaning treatment was 2.6% by weight. The drying treatment was performed under drying conditions of 70° C. and 5 minutes.
　（偏光板Ｐ１の作製）
　上記作製した偏光子の各主面に、それぞれ、トリアセチルセルロース（ＴＡＣ）フィルム（コニカミノルタ製、製品名「ＫＣ２ＵＡ」、厚さ２５μｍ）をポリビニルアルコール系接着剤により貼り合わせた。ただし、一方の主面に貼り合わせたＴＡＣフィルムには、偏光子側とは反対側の主面にハードコート（厚さ７μｍ）が形成されていた。このようにして、ハードコート付き保護層／偏光子／保護層（ハードコートなし）の構成を有する偏光板Ｐ１を得た。 (Preparation of polarizing plate P1)
A triacetyl cellulose (TAC) film (manufactured by Konica Minolta, product name “KC2UA”, thickness 25 μm) was attached to each main surface of the polarizer prepared above with a polyvinyl alcohol-based adhesive. However, in the TAC film attached to one main surface, a hard coat (7 μm thick) was formed on the main surface opposite to the polarizer side. Thus, a polarizing plate P1 having a structure of protective layer with hard coat/polarizer/protective layer (no hard coat) was obtained.
　＜位相差フィルムＲ１の作製＞
　（第１の位相差フィルムの作製）
　イソソルビド（ＩＳＢ）２６．２重量部、９，９－［４－（２－ヒドロキシエトキシ）フェニル］フルオレン（ＢＨＥＰＦ）１００．５重量部、１，４－シクロヘキサンジメタノール（１，４－ＣＨＤＭ）１０．７重量部、ジフェニルカーボネート（ＤＰＣ）１０５．１重量部、及び触媒として炭酸セシウム（０．２重量％水溶液）０．５９１重量部を反応容器に投入し、窒素雰囲気下にて溶解させた（約１５分）。このとき、反応容器の熱媒温度は１５０℃とし、必要に応じて撹拌を実施した。次に、反応容器内の圧力を１３．３ｋＰａに減圧すると共に、熱媒温度を１９０℃まで１時間で上昇させた。熱媒温度の上昇に伴って発生するフェノールは、反応容器外へ抜き出した（以下、同じ）。次に、反応容器内の温度を１９０℃で１５分保持した後、反応容器内の圧力を６．６７ｋＰａに変更すると共に、熱媒温度を２３０℃まで１５分で上昇させた。反応容器が備える撹拌機の撹拌トルクが上昇してきた時点で、熱媒温度を２５０℃まで８分で上昇させ、更に、反応容器内の圧力を０．２００ｋＰａ以下とした。所定の撹拌トルクに到達後、反応を終了させ、生成した反応物を水中に押し出してペレット化した。このようにして、ＢＨＥＰＦ／ＩＳＢ／１，４－ＣＨＤＭ＝４７．４モル％／３７．１モル％／１５．５モル％の組成を有するポリカーボネート樹脂を得た。得られたポリカーボネート樹脂のガラス転移温度は１３６．６℃であり、還元粘度は０．３９５ｄＬ／ｇであった。 <Preparation of retardation film R1>
(Preparation of first retardation film)
Isosorbide (ISB) 26.2 parts by weight, 9,9-[4-(2-hydroxyethoxy)phenyl]fluorene (BHEPF) 100.5 parts by weight, 1,4-cyclohexanedimethanol (1,4-CHDM) 10 .7 parts by weight, 105.1 parts by weight of diphenyl carbonate (DPC), and 0.591 parts by weight of cesium carbonate (0.2% by weight aqueous solution) as a catalyst were charged into a reaction vessel and dissolved under a nitrogen atmosphere ( about 15 minutes). At this time, the temperature of the heat medium in the reaction vessel was set at 150° C., and stirring was carried out as necessary. Next, the pressure inside the reaction vessel was reduced to 13.3 kPa, and the temperature of the heat medium was raised to 190° C. in 1 hour. Phenol generated as the temperature of the heat medium increased was discharged out of the reaction vessel (the same applies hereinafter). Next, after maintaining the temperature in the reaction vessel at 190° C. for 15 minutes, the pressure in the reaction vessel was changed to 6.67 kPa, and the temperature of the heat medium was raised to 230° C. in 15 minutes. When the stirring torque of the stirrer provided in the reaction vessel increased, the temperature of the heat medium was raised to 250° C. in 8 minutes, and the pressure in the reaction vessel was reduced to 0.200 kPa or less. After reaching a predetermined stirring torque, the reaction was terminated, and the produced reaction product was extruded into water and pelletized. Thus, a polycarbonate resin having a composition of BHEPF/ISB/1,4-CHDM=47.4 mol %/37.1 mol %/15.5 mol % was obtained. The obtained polycarbonate resin had a glass transition temperature of 136.6° C. and a reduced viscosity of 0.395 dL/g.
　作製したポリカーボネート樹脂のペレットを８０℃で５時間真空乾燥した後、単軸押出機（いすず化工機製、スクリュー径２５ｍｍ、シリンダー設定温度２２０℃）、Ｔダイ（幅２００ｍｍ、設定温度２２０℃）、チルロール（設定温度１２０～１３０℃）及び巻取機を備えたフィルム製膜装置を用いて、厚さ１２０μｍの長尺状の樹脂フィルムを得た。次に、得られた樹脂フィルムを、テンター延伸機により、延伸温度１３７－１３９℃、延伸倍率２．５倍で幅方向に延伸して、第１の位相差フィルムを得た。 After vacuum drying the prepared polycarbonate resin pellets at 80 ° C. for 5 hours, a single screw extruder (manufactured by Isuzu Kakoki, screw diameter 25 mm, cylinder set temperature 220 ° C.), T die (width 200 mm, set temperature 220 ° C.), chill roll A long resin film having a thickness of 120 μm was obtained using a film forming apparatus equipped with a set temperature of 120 to 130° C. and a winder. Next, the obtained resin film was stretched in the width direction with a tenter stretching machine at a stretching temperature of 137 to 139° C. and a stretching ratio of 2.5 times to obtain a first retardation film.
　（第２の位相差フィルムの作製）
　下記化学式（Ｉ）（式中、６５及び３５は、各構成単位のモル％）により示される側鎖型液晶ポリマー（重量平均分子量５０００）２０重量部、ネマチック液晶相を示す重合性液晶（ＢＡＳＦ製、商品名「ＰａｌｉｏｃｏｌｏｒＬＣ２４２」）８０重量部、及び光重合開始剤（チバスペシャリティーケミカルズ製、商品名「イルガキュア９０７」）５重量部をシクロペンタノン２００重量部に溶解して、液晶塗工液を調製した。次に、基材フィルムであるノルボルネン系樹脂フィルム（日本ゼオン製、商品名「ゼオネックス」）の表面に、調製した液晶塗工液をバーコーターにより塗工した後、８０℃で４分間、加熱及び乾燥させて、塗布膜に含まれる液晶を配向させた。次に、紫外線の照射により塗布膜を硬化させて、第２の位相差フィルムである液晶固化層（厚さ０．５８μｍ）を基材フィルム上に形成した。波長５５０ｎｍの光に対する液晶固化層の面内位相差Ｒｅは０ｎｍ、厚さ方向の位相差Ｒｔｈは－７１ｎｍであり（ｎｘ＝１．５３２６、ｎｙ＝１．５３２６、ｎｚ＝１．６５５０）、液晶固化層は、ｎｚ＞ｎｘ＝ｎｙの屈折率特性を示した。 (Production of second retardation film)
20 parts by weight of a side chain type liquid crystal polymer (weight average molecular weight 5000) represented by the following chemical formula (I) (where 65 and 35 are mol% of each structural unit), a polymerizable liquid crystal exhibiting a nematic liquid crystal phase (manufactured by BASF) , trade name “Paliocolor LC242”) 80 parts by weight, and a photopolymerization initiator (manufactured by Ciba Specialty Chemicals, trade name “Irgacure 907”) 5 parts by weight are dissolved in 200 parts by weight of cyclopentanone to form a liquid crystal coating liquid. prepared. Next, the surface of a norbornene-based resin film (manufactured by Nippon Zeon, trade name “Zeonex”), which is a base film, is coated with the prepared liquid crystal coating liquid using a bar coater, and then heated at 80 ° C. for 4 minutes. By drying, the liquid crystal contained in the coating film was oriented. Next, the coating film was cured by irradiation with ultraviolet rays to form a liquid crystal solidified layer (thickness: 0.58 μm) as a second retardation film on the substrate film. The in-plane retardation Re of the liquid crystal solidified layer for light with a wavelength of 550 nm is 0 nm, and the thickness direction retardation Rth is -71 nm (nx = 1.5326, ny = 1.5326, nz = 1.6550). The solidified layer exhibited refractive index properties of nz>nx=ny.
Figure JPOXMLDOC01-appb-C000001
Figure JPOXMLDOC01-appb-C000001
　（位相差フィルムＲ１の作製）
　上記作製した第１の位相差フィルムの一方の面と、第２の位相差フィルムの液晶固化層とを接着剤を介して貼合せて、位相差フィルムＲ１を作製した。 (Preparation of retardation film R1)
One surface of the first retardation film prepared above and the liquid crystal solidified layer of the second retardation film were pasted together via an adhesive to prepare a retardation film R1.
　＜粘着シート付き円偏光板の作製＞
　（層間粘着剤の作製）
　撹拌羽根、温度計、窒素ガス導入管、及び冷却器を備えた４つ口フラスコに、ブチルアクリレート７９．９重量部、ベンジルアクリレート１５重量部、アクリル酸５重量部及び４－ヒドロキシブチルアクリレート０．１重量部を含有する単量体混合物を仕込んだ。次に、単量体混合物１００重量部に対して、重合開始剤として２，２’－アゾイソブチロニトリル０．１重量部を酢酸エチルと共に加え、緩やかに撹拌しながら窒素ガスを導入してフラスコ内を窒素置換した後、フラスコ内の液温を５５℃付近に保って重合反応を７時間進行させた。次に、得られた反応液に酢酸エチルを加えて固形分濃度３０重量％に調整して、層間粘着剤に使用する（メタ）アクリル系ポリマーの溶液を得た。得られたポリマーの重量平均分子量は、２２０万であった。 <Preparation of circularly polarizing plate with adhesive sheet>
(Production of interlayer adhesive)
79.9 parts by weight of butyl acrylate, 15 parts by weight of benzyl acrylate, 5 parts by weight of acrylic acid and 0.5 parts by weight of 4-hydroxybutyl acrylate were placed in a four-necked flask equipped with a stirring blade, a thermometer, a nitrogen gas inlet tube, and a condenser. A monomer mixture containing 1 part by weight was charged. Next, 0.1 part by weight of 2,2'-azoisobutyronitrile as a polymerization initiator was added to 100 parts by weight of the monomer mixture together with ethyl acetate, and nitrogen gas was introduced while gently stirring. After the inside of the flask was replaced with nitrogen, the polymerization reaction was allowed to proceed for 7 hours while maintaining the liquid temperature in the flask around 55°C. Next, ethyl acetate was added to the resulting reaction solution to adjust the solid content concentration to 30% by weight to obtain a solution of a (meth)acrylic polymer used as an interlaminar pressure-sensitive adhesive. The weight average molecular weight of the obtained polymer was 2,200,000.
　次に、得られた（メタ）アクリル系ポリマーの溶液に、当該溶液の固形分１００重量部に対して、トリメチロールプロパン／トリレンジイソシアネート３量体付加物（東ソー製、商品名「コロネートＬ」）０．５重量部、過酸化物系架橋剤であるベンゾイルパーオキサイド０．１重量部、エポキシ基含有シランカップリング剤（信越化学工業製、商品名「ＫＢＭ－４０３）０．２重量部、及び反応性シリル基を有するポリエーテル化合物（カネカ製、サイリルＳＡＴ１０）０．５重量部を混合して、偏光板Ｐ１と位相差フィルムＲ１とを接合するための層間粘着剤に使用する粘着剤組成物ＰＳＡ１を得た。 Next, in the solution of the obtained (meth)acrylic polymer, trimethylolpropane/tolylene diisocyanate trimer adduct (manufactured by Tosoh, trade name "Coronate L") is added to 100 parts by weight of the solid content of the solution. ) 0.5 parts by weight, 0.1 parts by weight of benzoyl peroxide which is a peroxide cross-linking agent, epoxy group-containing silane coupling agent (manufactured by Shin-Etsu Chemical Co., Ltd., trade name "KBM-403) 0.2 parts by weight, and a polyether compound having a reactive silyl group (manufactured by Kaneka, Silyl SAT10) 0.5 parts by weight is mixed, and an adhesive composition used as an interlayer adhesive for bonding the polarizing plate P1 and the retardation film R1 The product PSA1 was obtained.
　（層間粘着剤層付き偏光板の作製）
　上記作製した粘着剤組成物ＰＳＡ１を、剥離面にシリコーン処理が施された剥離フィルムである、厚さ３８μｍのポリエチレンテレフタレート（ＰＥＴ）フィルム（三菱化学ポリエステルフィルム製、ＭＲＦ３８）の剥離面に対して、乾燥後の層の厚さが１２μｍとなるように塗布し、１５５℃で１分間乾燥処理して、層間粘着剤層を形成した。次に、形成した層間粘着剤層を偏光板Ｐ１における保護層（ハードコートなし）側に転写して、層間粘着剤層付き偏光板を得た。 (Preparation of polarizing plate with interlayer pressure-sensitive adhesive layer)
The pressure-sensitive adhesive composition PSA1 prepared above is applied to the release surface of a polyethylene terephthalate (PET) film (manufactured by Mitsubishi Chemical Polyester Film Co., Ltd., MRF38) having a thickness of 38 μm, which is a release film having a silicone-treated release surface. It was coated so that the thickness of the layer after drying was 12 μm, and dried at 155° C. for 1 minute to form an interlayer pressure-sensitive adhesive layer. Next, the formed interlayer pressure-sensitive adhesive layer was transferred to the protective layer (no hard coat) side of the polarizing plate P1 to obtain a polarizing plate with an interlayer pressure-sensitive adhesive layer.
　（粘着シート付き円偏光板の作製）
　位相差フィルムＲ１における第２の位相差フィルム側（第２の位相差フィルムを作製する際に基材フィルムとして用いたノルボルネン系樹脂フィルムは剥離）に、実施例及び比較例で作製した各粘着シート（時点Ｔ0から７日間以上経過したもの）を剥離フィルムから転写して貼りつけた。次に、位相差フィルムＲ１における第１の位相差フィルム側に、上記作製した層間粘着剤層付き偏光板を、層間粘着剤層を介して貼りつけて、粘着シート付き円偏光板を得た。位相差フィルムＲ１と層間粘着剤層付き偏光板との貼りつけは、第１の位相差フィルムの側から見て、第１の位相差フィルムの遅相軸と偏光子の吸収軸との成す角度が反時計回りに４５度となるように実施した。 (Preparation of circularly polarizing plate with adhesive sheet)
On the second retardation film side of the retardation film R1 (the norbornene-based resin film used as the base film when producing the second retardation film is peeled off), each pressure-sensitive adhesive sheet prepared in Examples and Comparative Examples (7 days or more after time T 0 ) was transferred from the release film and pasted. Next, the polarizing plate with an interlayer pressure-sensitive adhesive layer prepared above was attached to the first retardation film side of the retardation film R1 via the interlayer pressure-sensitive adhesive layer to obtain a circularly polarizing plate with an pressure-sensitive adhesive sheet. The attachment of the retardation film R1 and the polarizing plate with an interlayer pressure-sensitive adhesive layer is performed by adjusting the angle formed by the slow axis of the first retardation film and the absorption axis of the polarizer when viewed from the side of the first retardation film. was 45 degrees counterclockwise.
　次に、実施例及び比較例の各粘着シートの作製方法を説明する。 Next, the method for producing each pressure-sensitive adhesive sheet of Examples and Comparative Examples will be described.
　以下の説明に示す略称又は名称と化合物との対応は、次のとおりである。
　ＢＡ：ｎ－ブチルアクリルレート
　ＢｚＡ：ベンジルアクリレート
　ＡＡ：アクリル酸
　ＨＢＡ：４－ヒドロキシブチルアクリレート
　ＡＩＢＮ：２，２’－アゾビスイソブチロニトリル
　Ｃ／Ｌ：トリメチロールプロパン／トリレンジイソシアネート３量体付加物（イソシアネート系架橋剤；東ソー製、コロネートＬ）
　過酸化物：ベンゾイルパーオキサイド（日本油脂社製、ナイパーＢＭＴ）
　ＴｅｔｒａｄＣ：１，３－ビス（Ｎ，Ｎ－ジグリシジルアミノメチル）シクロヘキサン（多官能エポキシ系架橋剤；三菱ガス化学製、テトラッドＣ）
　ＫＢＭ４０３：３－グリシドキシプロピルトリエトキシシラン（シランカップリング剤；信越化学工業製、ＫＢＭ４０３）
　ＴＭＰ：トリメチロールプロパン
　ＥＤＰ：エチレンジアミン／プロピレンオキサイド４量体付加物（ポリエーテルポリオール系架橋促進剤；ＡＤＥＫＡ製、ＥＤＰ－３００） The correspondence between the abbreviations or names shown in the following description and the compounds is as follows.
BA: n-butyl acrylate BzA: benzyl acrylate AA: acrylic acid HBA: 4-hydroxybutyl acrylate AIBN: 2,2'-azobisisobutyronitrile C/L: trimethylolpropane/tolylene diisocyanate trimer addition Material (isocyanate-based cross-linking agent; manufactured by Tosoh, Coronate L)
Peroxide: benzoyl peroxide (manufactured by NOF Corporation, Nyper BMT)
TetradC: 1,3-bis(N,N-diglycidylaminomethyl)cyclohexane (polyfunctional epoxy-based cross-linking agent; manufactured by Mitsubishi Gas Chemical Co., Ltd., Tetrad C)
KBM403: 3-glycidoxypropyltriethoxysilane (silane coupling agent; manufactured by Shin-Etsu Chemical Co., Ltd., KBM403)
TMP: trimethylolpropane EDP: ethylenediamine/propylene oxide tetramer adduct (polyether polyol cross-linking accelerator; manufactured by ADEKA, EDP-300)
　［（メタ）アクリル系ポリマー（Ａ）の作製］
　（合成例１）
　撹拌羽根、温度計、窒素ガス導入管、及び冷却器を備えた４つ口フラスコに、ＢＡ７９．９重量部、ＢｚＡ１５．０重量部、ＡＡ５．０重量部及びＨＢＡ０．１重量部を仕込んだ。次に、ＢＡ、ＢｚＡ、ＡＡ及びＨＢＡの混合物１００重量部に対して、重合開始剤としてＡＩＢＮ０．１重量部を加え、緩やかに撹拌しながら窒素ガスを導入してフラスコ内を窒素置換した後、フラスコ内の液温を５５℃付近に保って重合反応を７時間進行させた。次に、得られた反応液に酢酸エチルを加えて固形分濃度１２重量％に調整して、（メタ）アクリル系ポリマー（Ａ－１）の溶液を得た。（メタ）アクリル系ポリマー（Ａ－１）の重量平均分子量（Ｍｗ）は２２０万であった。 [Preparation of (meth)acrylic polymer (A)]
(Synthesis example 1)
A four-necked flask equipped with a stirring blade, a thermometer, a nitrogen gas inlet tube and a condenser was charged with 79.9 parts by weight of BA, 15.0 parts by weight of BzA, 5.0 parts by weight of AA and 0.1 part by weight of HBA. Next, 0.1 part by weight of AIBN as a polymerization initiator was added to 100 parts by weight of a mixture of BA, BzA, AA and HBA, and nitrogen gas was introduced while gently stirring to replace the inside of the flask with nitrogen. The polymerization reaction was allowed to proceed for 7 hours while maintaining the liquid temperature in the flask at around 55°C. Next, ethyl acetate was added to the resulting reaction solution to adjust the solid content concentration to 12% by weight to obtain a solution of (meth)acrylic polymer (A-1). The (meth)acrylic polymer (A-1) had a weight average molecular weight (Mw) of 2,200,000.
　（合成例２）
　使用する単量体をＢＡ９４．９重量部、ＡＡ５．０重量部及びＨＢＡ０．１重量部に変更した以外は、合成例１と同様にして、（メタ）アクリル系ポリマー（Ａ－２）の溶液を得た。（メタ）アクリル系ポリマー（Ａ－２）の重量平均分子量（Ｍｗ）は２２０万であった。 (Synthesis example 2)
A solution of (meth)acrylic polymer (A-2) was prepared in the same manner as in Synthesis Example 1, except that the monomers used were changed to 94.9 parts by weight of BA, 5.0 parts by weight of AA and 0.1 parts by weight of HBA. got The (meth)acrylic polymer (A-2) had a weight average molecular weight (Mw) of 2,200,000.
　合成例１，２で使用した単量体及び重合開始剤の種類及び仕込み量、並びに得られたポリマーの重量平均分子量（Ｍｗ）を以下の表１にまとめる。 The types and amounts of the monomers and polymerization initiators used in Synthesis Examples 1 and 2, and the weight average molecular weight (Mw) of the resulting polymer are summarized in Table 1 below.
Figure JPOXMLDOC01-appb-T000002
Figure JPOXMLDOC01-appb-T000002
　［粘着剤組成物及び粘着シートの作製］
　（実施例１～７、比較例１，２）
　以下の表２に示すように（メタ）アクリル系ポリマー（Ａ）の固形分１００重量部に対して架橋剤等を混合して、溶剤型の粘着剤組成物を得た。 [Preparation of adhesive composition and adhesive sheet]
(Examples 1 to 7, Comparative Examples 1 and 2)
As shown in Table 2 below, 100 parts by weight of the solid content of the (meth)acrylic polymer (A) was mixed with a crosslinking agent and the like to obtain a solvent-type pressure-sensitive adhesive composition.
Figure JPOXMLDOC01-appb-T000003
Figure JPOXMLDOC01-appb-T000003
　次に、剥離面にシリコーン処理が施された剥離フィルムである、厚さ３８μｍのＰＥＴフィルム（三菱化学ポリエステルフィルム製、ＭＲＦ３８）の剥離面に対して、得られた粘着剤組成物を塗布した後、９０℃（実施例５，６のみ１１０℃）に設定した空気循環式恒温オーブンにて１００秒間乾燥させて、実施例１～７及び比較例１，２の粘着シート（厚さ１５μｍ）を形成した。粘着剤組成物の塗布には、ファウンテンコーターを用いた。作製した各粘着シートの評価結果を、以下の表３に示す。なお、実施例５，６についても、各ゲル分率を評価する際の乾燥条件は、上述の９０℃及び１００秒間である。 Next, after applying the obtained pressure-sensitive adhesive composition to the release surface of a 38 μm thick PET film (manufactured by Mitsubishi Chemical Polyester Film Co., Ltd., MRF38), which is a release film having a silicone-treated release surface. , dried for 100 seconds in an air circulating constant temperature oven set at 90 ° C. (110 ° C. for Examples 5 and 6) to form adhesive sheets (thickness 15 μm) of Examples 1 to 7 and Comparative Examples 1 and 2. did. A fountain coater was used to apply the adhesive composition. The evaluation results of each pressure-sensitive adhesive sheet produced are shown in Table 3 below. Also in Examples 5 and 6, the drying conditions for evaluating each gel fraction were the above-described 90° C. and 100 seconds.
Figure JPOXMLDOC01-appb-T000004
Figure JPOXMLDOC01-appb-T000004
　表３に示すように、ゲル分率Ｇ2hが６０重量％未満であると共にＧ24hが６０重量％以上である実施例の粘着シートは、比較例の粘着シートに比べて、寸法の変化を抑えることに適するとともに、高い耐久性を示した。 As shown in Table 3, the pressure-sensitive adhesive sheets of Examples having a gel fraction G2h of less than 60% by weight and a G24h of 60% by weight or more suppress dimensional changes compared to the pressure-sensitive adhesive sheets of Comparative Examples. It is suitable for various applications and exhibits high durability.
　本発明の粘着剤組成物によれば、例えば、画像表示装置に用いる粘着シートを形成できる。 According to the adhesive composition of the present invention, for example, an adhesive sheet for use in image display devices can be formed.

Claims (15)

  1. 　（メタ）アクリル系ポリマー（Ａ）を主成分として含む粘着剤組成物であって、
    　架橋剤（Ｂ）を更に含み、
    　前記粘着剤組成物から粘着シートを形成したときに、
    　　前記粘着シートを形成した時点Ｔ0から２時間経過した時点での前記粘着シートのゲル分率Ｇ2hが６０重量％未満であり、
    　　前記時点Ｔ0から２４時間経過した時点での前記粘着シートのゲル分率Ｇ24hが６０重量％以上である、粘着剤組成物。     A pressure-sensitive adhesive composition containing a (meth)acrylic polymer (A) as a main component,
    further comprising a cross-linking agent (B),
    When forming a pressure-sensitive adhesive sheet from the pressure-sensitive adhesive composition,
    The gel fraction G 2h of the pressure-sensitive adhesive sheet is less than 60% by weight at the time when 2 hours have passed since the time T 0 of forming the pressure-sensitive adhesive sheet,
    The pressure-sensitive adhesive composition, wherein the pressure-sensitive adhesive sheet has a gel fraction G 24h of 60% by weight or more after 24 hours from the time T 0 .
  2. 　前記ゲル分率Ｇ2hに対する前記ゲル分率Ｇ24hの比Ｇ24h／Ｇ2hが２以上である、請求項１に記載の粘着剤組成物。 The adhesive composition according to claim 1, wherein the ratio G24h / G2h of said gel fraction G24h to said gel fraction G2h is 2 or more.
  3. 　前記時点Ｔ0の直後における前記粘着シートのゲル分率Ｇ0が３重量％以上５０重量％以下である、請求項１又は２に記載の粘着剤組成物。 The pressure-sensitive adhesive composition according to claim 1 or 2, wherein the gel fraction G0 of the pressure-sensitive adhesive sheet immediately after the time T0 is 3% by weight or more and 50% by weight or less.
  4. 　前記時点Ｔ0から７日間経過した時点での前記粘着シートのゲル分率Ｇ7dが９０重量％以上である、請求項１～３のいずれか１項に記載の粘着剤組成物。 4. The pressure-sensitive adhesive composition according to any one of claims 1 to 3, wherein the pressure-sensitive adhesive sheet has a gel fraction G 7d of 90% by weight or more after 7 days from the time T 0 .
  5. 　溶剤型である、請求項１～４のいずれか１項に記載の粘着剤組成物。 The pressure-sensitive adhesive composition according to any one of claims 1 to 4, which is solvent-based.
  6. 　前記架橋剤（Ｂ）がイソシアネート系である、請求項１～５のいずれか１項に記載の粘着剤組成物。 The pressure-sensitive adhesive composition according to any one of claims 1 to 5, wherein the cross-linking agent (B) is isocyanate-based.
  7. 　前記架橋剤（Ｂ）がトリレンジイソシアネート系である、請求項１～５のいずれか１項に記載の粘着剤組成物。 The pressure-sensitive adhesive composition according to any one of claims 1 to 5, wherein the cross-linking agent (B) is tolylene diisocyanate-based.
  8. 　前記架橋剤（Ｂ）が３官能以上である、請求項１～７のいずれか１項に記載の粘着剤組成物。 The pressure-sensitive adhesive composition according to any one of claims 1 to 7, wherein the cross-linking agent (B) is trifunctional or higher.
  9. 　前記架橋剤（Ｂ）の配合量が、前記（メタ）アクリル系ポリマー（Ａ）１００重量部に対して５重量部以上である、請求項１～８のいずれか１項に記載の粘着剤組成物。 The pressure-sensitive adhesive composition according to any one of claims 1 to 8, wherein the amount of the cross-linking agent (B) is 5 parts by weight or more with respect to 100 parts by weight of the (meth)acrylic polymer (A). thing.
  10. 　前記（メタ）アクリル系ポリマー（Ａ）が、芳香環含有単量体に由来する構成単位を含む、請求項１～９のいずれか１項に記載の粘着剤組成物。 The pressure-sensitive adhesive composition according to any one of claims 1 to 9, wherein the (meth)acrylic polymer (A) contains a structural unit derived from an aromatic ring-containing monomer.
  11. 　前記（メタ）アクリル系ポリマー（Ａ）が、水酸基含有単量体に由来する構成単位を１重量％以下の含有率で含む、請求項１～１０のいずれか１項に記載の粘着剤組成物。 The pressure-sensitive adhesive composition according to any one of claims 1 to 10, wherein the (meth)acrylic polymer (A) contains a structural unit derived from a hydroxyl group-containing monomer at a content of 1% by weight or less. .
  12. 　請求項１～１１のいずれか１項に記載の粘着剤組成物から形成された粘着シート。 A pressure-sensitive adhesive sheet formed from the pressure-sensitive adhesive composition according to any one of claims 1 to 11.
  13. 　２５℃の貯蔵弾性率Ｇ’が０．４ＭＰａ以上である、請求項１２に記載の粘着シート。 The pressure-sensitive adhesive sheet according to claim 12, wherein the storage elastic modulus G' at 25°C is 0.4 MPa or more.
  14. 　請求項１２又は１３に記載の粘着シートと、光学フィルムと、を含む、光学積層体。 An optical laminate comprising the adhesive sheet according to claim 12 or 13 and an optical film.
  15. 　請求項１４に記載の光学積層体を備える画像表示装置。
          An image display device comprising the optical layered body according to claim 14 .
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