Optical laminate, image display device, and pressure-sensitive adhesive composition

Abstract

To provide an optical laminate excellent in peeling resistance at high temperature.SOLUTION: The provided optical laminate includes an optical substrate and a pressure-sensitive adhesive layer disposed on a surface of the optical substrate. The pressure-sensitive adhesive layer includes a pressure-sensitive adhesive composition containing a silane coupling agent. The silane coupling agent contains an isocyanuric ring and does not contain an isocyanate group. The surface on which the pressure-sensitive adhesive layer is disposed is a modified surface subjected to surface modification by energy irradiation.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to an optical laminate, an image display device, and a pressure-sensitive adhesive composition. [Background technology]

[0002] Various thin image display devices, such as liquid crystal displays and organic electroluminescence displays, typically include an optical laminate comprising an optical substrate and a pressure-sensitive adhesive layer disposed on the surface of the optical substrate. Examples of optical substrates include image-forming layers such as a liquid crystal layer and an organic electroluminescence light-emitting layer, optical films such as a polarizing plate and a retardation film, and a cover window. The pressure-sensitive adhesive layer is used to bond the various layers included in the optical laminate. In addition, in optical substrates composed of multiple layers, such as a polarizing plate composed of a polarizer and a polarizer protective film, the multiple layers may be bonded together by the pressure-sensitive adhesive layer.

[0003] Patent Document 1 discloses an optical laminate comprising a translucent adherend, a pressure-sensitive adhesive layer containing a specific silane coupling agent having an epoxy group at one end, and a polarizing plate. Patent Document 1 also describes that the inclusion of the silane coupling agent can improve the adhesion of the pressure-sensitive adhesive layer to a glass plate. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 7-20314 Summary of the Invention [Problem to be solved by the invention]

[0005] Image display devices can be exposed to high temperatures. For this reason, the optical laminate is required to be resistant to peeling between layers bonded via a pressure-sensitive adhesive layer even at high temperatures, in other words, to have excellent peel resistance at high temperatures. Furthermore, optical substrates other than glass substrates are often used in image display devices to reduce weight and improve functionality, and there is a demand for optical substrates other than glass substrates to be resistant to peeling. However, according to the inventors' investigations, the optical laminate of Patent Document 1 does not adequately meet this requirement.

[0006] An object of the present invention is to provide an optical layered body that has excellent peel resistance at high temperatures. [Means for solving the problem]

[0007] The present invention provides An optical substrate and a pressure-sensitive adhesive layer disposed on a surface of the optical substrate, the pressure-sensitive adhesive layer comprises a pressure-sensitive adhesive composition containing a silane coupling agent, The silane coupling agent contains an isocyanuric ring but does not contain an isocyanate group, an optical laminate, wherein the surface on which the pressure-sensitive adhesive layer is disposed is a modified surface that has been surface-modified by energy irradiation; to provide.

[0008] In another aspect, the present invention provides a method for producing a composition comprising: The optical laminate of the present invention, an image display device including an image display panel; to provide.

[0009] In another aspect, the present invention provides a method for producing a composition comprising: A pressure-sensitive adhesive composition that is disposed on a surface of an optical substrate of the optical laminate of the present invention, Contains a silane coupling agent, The silane coupling agent contains an isocyanuric ring but does not contain an isocyanate group, a pressure-sensitive adhesive composition, wherein the surface on which the pressure-sensitive adhesive composition is placed is a modified surface that has been surface-modified by energy irradiation; to provide. [Effects of the Invention]

[0010] According to the present invention, an optical layered body having excellent peel resistance at high temperatures can be provided. [Brief explanation of the drawings]

[0011] [Figure 1] FIG. 1 is a cross-sectional view schematically showing an example of the optical layered body of the present invention. [Figure 2] FIG. 2 is a cross-sectional view schematically showing another example of the optical layered body of the present invention. [Figure 3] FIG. 3 is a cross-sectional view schematically showing still another example of the optical layered body of the present invention. [Figure 4] FIG. 4 is a cross-sectional view schematically showing an example of an image display device of the present invention. [Figure 5A] FIG. 5A is a diagram showing the distribution of a silane coupling agent in the pressure-sensitive adhesive layer of the optical laminate produced in Example 3. FIG. [Figure 5B] 5B is a diagram showing the distribution of a silane coupling agent in the pressure-sensitive adhesive layer of the optical laminate produced in Comparative Example 1. FIG. DETAILED DESCRIPTION OF THE INVENTION

[0012] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the accompanying drawings, but is not limited to the following embodiments.

[0013] [Optical laminate] The optical laminate of this embodiment is shown in FIG. 1. The optical laminate 100 of FIG. 1 includes an optical substrate 1 and a pressure-sensitive adhesive layer 2. The pressure-sensitive adhesive layer 2 is disposed on a surface 11 of the optical substrate 1. The pressure-sensitive adhesive layer 2 and the optical substrate 1 are in contact with each other. The surface 11 on which the pressure-sensitive adhesive layer 2 is disposed is a modified surface 12 that has been surface-modified by energy irradiation. The pressure-sensitive adhesive layer 2 contains a pressure-sensitive adhesive composition containing a silane coupling agent (hereinafter referred to as "Si agent (X)") that contains an isocyanuric ring but no isocyanate group. The isocyanuric ring has a structure shown in the following formula (1). At least one * (bond) in formula (1) is bonded to a molecular structure (Y) containing a Si atom and a hydrolyzable group. The molecular structure (Y) may be bonded to two * or all three *.

[0014] [ka]

[0015] The inclusion of the Si agent (X) is thought to contribute to maintaining the cohesive strength of the pressure-sensitive adhesive layer 2 at high temperatures (e.g., 50 to 100°C, typically 80°C) and improving the adhesive strength at high temperatures to the modified surface 12 of the optical substrate 1. Maintaining the cohesive strength, in other words, suppressing cohesive failure of the pressure-sensitive adhesive layer 2, and improving the adhesive strength work in the direction of improving peel resistance at high temperatures. The above contributions are presumably due to the following: (I) the distribution of molecular structures (Y) capable of forming covalent bonds with the modified surface 12 in the pressure-sensitive adhesive layer 2 can be more uniform, particularly when the molecular structures (Y) are bonded to multiple * in the isocyanuric ring, (II) the NCO structures capable of forming hydrogen bonds with the modified surface 12 are spread evenly in three directions in the isocyanuric ring, and (III) the NCO structures of the isocyanuric ring, unlike isocyanate groups, are less likely to form bonds with other materials that may be contained in the pressure-sensitive adhesive layer 2, such as polymers and crosslinking agents, thereby improving the uniformity of the crosslinked structure in the pressure-sensitive adhesive layer 2. According to the studies of the present inventors, the cohesive strength of the pressure-sensitive adhesive layer 2 can be evaluated using the 800% modulus.

[0016] Furthermore, the Si agent (X) may be present in a relatively large amount in a region 21 in the pressure-sensitive adhesive layer 2 near the interface 3 with the optical substrate 1. The uneven distribution in the region 21 may act to further improve the adhesive strength to the modified surface 12 at high temperatures. In view of the above, the Si agent (X) may be unevenly distributed in a region 21 in the pressure-sensitive adhesive layer 2 near the interface 3 with the optical substrate 1. The region 21 near the interface 3 means, for example, a region occupying 20% ​​of the thickness of the pressure-sensitive adhesive layer 2 in the thickness direction from the interface 3. The distribution of the Si agent (X) in the pressure-sensitive adhesive layer 2 can be confirmed by an evaluation method capable of elemental analysis in the thickness direction of the layer, such as time-of-flight secondary ion mass spectrometry (TOF-SIMS) combined with etching ions. The uneven distribution can be confirmed, for example, by measuring the etching time (corresponding to the thickness direction of the pressure-sensitive adhesive layer 2) on the horizontal axis and the SiOH concentration on the vertical axis obtained by TOF-SIMS. + In the pressure-sensitive adhesive layer 2 in which the Si agent (X) is unevenly distributed, the SiOH + The sum of the areas of the peaks is the SiOH measurable in the adhesive layer 2. + It may be 50% or more of the sum of the peak areas, 60% or more, 70% or more, 80% or more, or even 90% or more. + The strength of the adhesive layer 2 is determined by the TOF-SIMS evaluation. + The m / z may be a value normalized based on the intensities of ions that do not overlap (normalized intensity). When the pressure-sensitive adhesive layer 2 contains an acrylic pressure-sensitive adhesive composition, the ion may be, for example, C2H3 + is.

[0017] In the example of FIG. 1, a pressure-sensitive adhesive layer 2 is disposed over the entire surface 11 of the optical substrate 1. When viewed perpendicularly to the surface 11, the optical substrate 1 and the pressure-sensitive adhesive layer 2 have the same shape. However, it is sufficient that the pressure-sensitive adhesive layer 12 is disposed over at least a portion of the surface 11. Furthermore, the entire surface 11 in FIG. 1 is a modified surface 12. However, it is sufficient that at least a portion of the surface 11 is a modified surface 12.

[0018] [Si agent (X)] The Si agent (X) contains an isocyanuric ring. The number of isocyanuric rings contained in the Si agent (X) may be 1 or 2 or more, or may be 1. In the Si agent (X), the number of Si atoms per isocyanuric ring may be 1, more than 1, 2 or more, or even 3 or more. The number of Si atoms contained in one molecular structure (Y) is not limited, and is typically 1.

[0019] The Si atom of the Si agent (X) may have a molecular structure containing a hydrolyzable group bonded thereto. The hydrolyzable group is, for example, an alkoxy group having 1 to 4 carbon atoms, and may be a methoxy group, an ethoxy group, or a methoxy group. The hydrolyzable group may be directly bonded to the Si atom.

[0020] The Si agent (X) does not contain an isocyanate group. The Si agent (X) may not contain a reactive functional group other than an isocyanate group, and in particular may not contain a reactive functional group other than an isocyanate group at its terminal. However, hydrolyzable groups and isocyanuric rings bonded to Si atoms are excluded from the reactive functional groups. Examples of reactive functional groups include epoxy groups, amino groups, vinyl groups, styryl groups, (meth)acrylic groups, ureido groups, and mercapto groups, particularly epoxy groups, amino groups, and epoxy groups. These groups have lower reactivity with other materials that may be contained in the pressure-sensitive adhesive layer 2 than isocyanate groups. However, the absence of a reactive functional group contributes to improving the uniformity of the crosslinked structure in the pressure-sensitive adhesive layer 2. In addition, amino groups are more likely to react with materials other than polymers, such as crosslinking agents.

[0021] An example of the Si agent (X) is shown in the following formula (2). The Si agent (X) in formula (2) is tris-(trialkoxysilylalkyl)isocyanurate. R in formula (2) 1 , R 2 and R 3 are each independently an alkylene group having 1 to 6 carbon atoms, and may be an alkyl group having 2 to 4 carbon atoms or a propyl group. 11 , R 12 , R 13 , R 21 , R 22, R 23 , R 31 , R 32 and R 33 are each independently an alkoxy group having 1 to 4 carbon atoms, and may be a methoxy group or an ethoxy group, or may be a methoxy group.

[0022] [ka]

[0023] [Adhesive composition] The content of the Si agent (X) in the pressure-sensitive adhesive composition contained in the pressure-sensitive adhesive layer 2 is, for example, 0.01% by weight to 5.0% by weight, and may be 0.01% by weight to 3.0% by weight, 0.05% by weight to 1.0% by weight, 0.1% by weight to 0.5% by weight, or even 0.15% by weight to 0.4% by weight. Appropriate control of the content contributes to more reliably improving peel resistance at high temperatures.

[0024] The pressure-sensitive adhesive composition contains, for example, a (meth)acrylic polymer. The (meth)acrylic polymer may be the main component of the pressure-sensitive adhesive composition; in other words, the pressure-sensitive adhesive composition may be acrylic. An acrylic pressure-sensitive adhesive composition is excellent in various properties such as transparency, processability, durability, and adhesion. However, the pressure-sensitive adhesive composition is not limited to acrylic. In this specification, (meth)acrylic means acrylic and / or methacrylic. Furthermore, the main component means the component with the largest content in the composition. The content of the main component is, for example, 50% by weight or more, and may be 70% by weight or more, 80% by weight or more, 90% by weight or more, 95% by weight or more, 97% by weight or more, 98% by weight or more, or even 99% by weight or more.

[0025] The pressure-sensitive adhesive composition may contain one or more (meth)acrylic polymers.

[0026] <(Meth)acrylic polymer> The (meth)acrylic polymer may have units (a2) derived from a (meth)acrylic monomer (a1) having an alkyl group of 1 to 30 carbon atoms on its side chain, or may have units (a2) as a main unit. The alkyl group may be linear or branched. The (meth)acrylic polymer may have one or more types of units (a2).

[0027] Examples of monomer (a1) are 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. In this specification, the term "main unit" refers to a unit that accounts for, for example, 50% by weight or more, preferably 80% by weight or more, more preferably 90% by weight or more, and even more preferably 94% by weight or more of all the structural units contained in the polymer. The upper limit of the proportion of the main unit is, for example, 99.9% by weight or less, and may be 99.5% by weight or less.

[0028] The (meth)acrylic polymer may contain units (a2) derived from a monomer (a1) having a long-chain alkyl group on the side chain. The monomer (a1) is, for example, n-dodecyl (meth)acrylate. In this specification, the long-chain alkyl group refers to an alkyl group having 6 to 30 carbon atoms.

[0029] The (meth)acrylic polymer may have units (a2) derived from a monomer (a1) having a Tg in the range of −70° C. to −20° C. when made into a homopolymer. The units (a1) are, for example, 2-ethylhexyl acrylate.

[0030] The (meth)acrylic polymer may contain a unit other than the unit (a1). For example, the unit is a unit (b2) derived from a monomer (b1) copolymerizable with the monomer (a1). The (meth)acrylic polymer may contain one or more types of the unit (b2).

[0031] An example of the monomer (b1) is a (meth)acrylic monomer (c1) having a hydroxyl group. The monomer (b1) may be a hydroxyl group-containing (meth)acrylate monomer. Examples of the monomer (c1) are hydroxyalkyl (meth)acrylates such as 2-hydroxyethyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, 6-hydroxyhexyl (meth)acrylate, 8-hydroxyoctyl (meth)acrylate, 10-hydroxydecyl (meth)acrylate, and 12-hydroxylauryl (meth)acrylate, as well as (4-hydroxymethylcyclohexyl)-methyl acrylate. The monomer (c1) may be 2-hydroxyethyl (meth)acrylate or 4-hydroxybutyl (meth)acrylate, as these can improve the durability of the PSA composition.

[0032] Monomer (b1) may be an amino group-containing monomer or an amide group-containing monomer. Examples of amino group-containing monomers are N,N-dimethylaminoethyl (meth)acrylate and N,N-dimethylaminopropyl (meth)acrylate. Examples of the amide group-containing monomer include acrylamide-based monomers such as (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, and mercaptoethyl(meth)acrylamide; N-acryloyl heterocyclic monomers such as N-(meth)acryloylmorpholine, N-(meth)acryloylpiperidine, and N-(meth)acryloylpyrrolidine; and N-vinyl group-containing lactam-based monomers such as N-vinylpyrrolidone and N-vinyl-ε-caprolactam.

[0033] The monomer (b1) may be a carboxyl group-containing monomer. Examples of carboxyl group-containing monomers include (meth)acrylic acid, carboxyethyl (meth)acrylate, carboxypentyl (meth)acrylate, itaconic acid, maleic acid, fumaric acid, and crotonic acid. However, units derived from carboxyl group-containing monomers have a strong effect of increasing the elastic modulus of the pressure-sensitive adhesive layer 2, which tends to reduce the degree of freedom in designing the physical properties of the pressure-sensitive adhesive layer 2 containing a (meth)acrylic polymer having such units. Furthermore, (meth)acrylic polymers having such units may be corrosive to optical substrates, depending on the material contained in the optical substrate. From this perspective, the content of units derived from carboxyl group-containing monomers in the (meth)acrylic polymer is preferably 5% by weight or less, and may be 3% by weight or less, 1.5% by weight or less, 1% by weight or less, 0.5% by weight or less, or even 0% by weight (excluding such units).

[0034] Monomer (b1) may be a polyfunctional monomer. The use of a polyfunctional monomer allows the gel fraction of the PSA composition to be adjusted. Examples of polyfunctional monomers include polyfunctional acrylates such as 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(meth)acrylate, tetramethylolmethane tri(meth)acrylate, allyl (meth)acrylate, vinyl (meth)acrylate, epoxy acrylate, polyester acrylate, and urethane acrylate; and divinylbenzene. The polyfunctional acrylate is preferably 1,6-hexanediol diacrylate or dipentaerythritol hexa(meth)acrylate.

[0035] Examples of other monomers (b1) other than those mentioned above include (meth)acrylic acid alkoxyalkyl esters such as 2-methoxyethyl (meth)acrylate, 2-ethoxyethyl (meth)acrylate, methoxytriethylene glycol (meth)acrylate, 3-methoxypropyl (meth)acrylate, 3-ethoxypropyl (meth)acrylate, 4-methoxybutyl (meth)acrylate, and 4-ethoxybutyl (meth)acrylate; epoxy group-containing monomers such as glycidyl (meth)acrylate and methylglycidyl (meth)acrylate; sulfonic acid group-containing monomers such as sodium vinyl sulfonate; phosphoric acid group-containing monomers; (meth) ) (meth)acrylates having an alicyclic hydrocarbon group such as cyclopentyl acrylate, cyclohexyl (meth)acrylate, and isobornyl (meth)acrylate; (meth)acrylates having an aromatic hydrocarbon group such as phenyl (meth)acrylate, phenoxyethyl (meth)acrylate, and benzyl (meth)acrylate; vinyl esters such as vinyl acetate and vinyl propionate; aromatic vinyl compounds such as styrene and vinyl toluene; olefins or dienes such as ethylene, propylene, butadiene, isoprene, and isobutylene; vinyl ethers such as vinyl alkyl ether; and vinyl chloride.

[0036] The total content of units derived from the hydroxyl group-containing (meth)acrylic monomer (c1), the amino group-containing monomer, the amide group-containing monomer, and the polyfunctional monomer in the (meth)acrylic polymer is, for example, 20% by weight or less, and may be 10% by weight or less, 8% by weight or less, or even 5% by weight or less. When the (meth)acrylic polymer contains such units, the total content of such units is, for example, 0.01% by weight or more, and may be 0.05% by weight or more.

[0037] The total content of units (b2) derived from monomer (b1) in the (meth)acrylic polymer is, for example, 30% by weight or less, may be 10% by weight or less, or may be 0% by weight (not including such units).

[0038] The (meth)acrylic polymer can be formed by polymerizing a group of monomers including the above-mentioned monomers by a known method. A monomer and a partial polymer of the monomer may also be polymerized. The polymerization can be carried out, for example, by solution polymerization, emulsion polymerization, bulk polymerization, thermal polymerization, or active energy ray polymerization. Since a pressure-sensitive adhesive composition having excellent optical transparency can be formed, solution polymerization and active energy ray polymerization are preferred. The polymerization is preferably carried out while avoiding contact between the monomer and / or the partial polymer and oxygen. For this purpose, for example, polymerization in an inert gas atmosphere such as nitrogen, or polymerization in a state where oxygen is blocked by a resin film or the like can be employed. The (meth)acrylic polymer formed may be in the form of any of a random copolymer, a block copolymer, a graft copolymer, or the like, and may also be a random copolymer.

[0039] The polymerization system for forming the (meth)acrylic polymer 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 photopolymerization initiator or a thermal polymerization initiator.

[0040] Examples of solvents used in 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 cyclohexane and 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.

[0041] Examples of polymerization initiators used in solution polymerization include azo polymerization initiators, peroxide polymerization initiators, and redox polymerization initiators. Examples of peroxide polymerization initiators include dibenzoyl peroxide and t-butyl permaleate. Among these, the azo polymerization initiators disclosed in JP-A-2002-69411 are preferred. Examples of the azo polymerization initiator include 2,2'-azobisisobutyronitrile (AIBN), 2,2'-azobis-2-methylbutyronitrile, 2,2'-azobis(2-methylpropionate)dimethyl, and 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, or may be 0.1 to 0.3 parts by weight, per 100 parts by weight of the total amount of monomers.

[0042] The active energy rays used in the active energy ray polymerization include, for example, ionizing radiation such as α rays, β rays, γ rays, neutron rays, and electron beams, as well as ultraviolet rays. The active energy ray is preferably ultraviolet rays. Polymerization by irradiation with ultraviolet rays is also called photopolymerization. The polymerization system for the active energy ray polymerization typically contains a photopolymerization initiator. The polymerization conditions for the active energy polymerization are not limited as long as a (meth)acrylic polymer is formed.

[0043] Examples of the photopolymerization initiator include a benzoin ether-based photopolymerization initiator, an acetophenone-based photopolymerization initiator, an α-ketol-based photopolymerization initiator, an aromatic sulfonyl chloride-based photopolymerization initiator, a photoactive oxime-based photopolymerization initiator, 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, although the photopolymerization initiator is not limited to the above examples.

[0044] Examples of benzoin ether-based photopolymerization initiators include benzoin methyl ether, benzoin ethyl ether, benzoin propyl ether, benzoin isopropyl ether, benzoin isobutyl ether, 2,2-dimethoxy-1,2-diphenylethan-1-one, and anisole methyl ether. Examples of acetophenone-based photopolymerization initiators include 2,2-diethoxyacetophenone, 2,2-dimethoxy-2-phenylacetophenone, 1-hydroxycyclohexyl phenyl ketone, 4-phenoxydichloroacetophenone, and 4-(t-butyl)dichloroacetophenone. Examples of α-ketol-based photopolymerization initiators include 2-methyl-2-hydroxypropiophenone and 1-[4-(2-hydroxyethyl)phenyl]-2-methylpropan-1-one. Examples of aromatic sulfonyl chloride-based photopolymerization initiators include 2-naphthalenesulfonyl chloride. An example of a photoactive oxime-based photopolymerization initiator is 1-phenyl-1,1-propanedione-2-(o-ethoxycarbonyl)-oxime. An example of a benzoin-based photopolymerization initiator is benzoin. An example of a benzyl-based photopolymerization initiator is benzil. An example of a benzophenone-based photopolymerization initiator is benzophenone, benzoylbenzoic acid, 3,3'-dimethyl-4-methoxybenzophenone, polyvinylbenzophenone, or α-hydroxycyclohexyl phenyl ketone. An example of a ketal-based photopolymerization initiator is benzil dimethyl ketal. An example of a thioxanthone-based photopolymerization initiator is thioxanthone, 2-chlorothioxanthone, 2-methylthioxanthone, 2,4-dimethylthioxanthone, isopropylthioxanthone, 2,4-diisopropylthioxanthone, or dodecylthioxanthone.

[0045] 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 parts by weight, relative to 100 parts by weight of the total amount of the monomers.

[0046] The polyfunctional monomer (such as a polyfunctional acrylate) that is the monomer (b1) can be used in both solvent-based and active energy ray-curable pressure-sensitive adhesive compositions. When both the polyfunctional monomer and the photopolymerization initiator are used in a solvent-based pressure-sensitive adhesive composition, for example, the solvent may be removed by thermal drying, and then the pressure-sensitive adhesive composition may be cured by irradiation with active energy rays.

[0047] The weight average molecular weight (Mw) of the (meth)acrylic polymer is, for example, 1 million or more, and may be 1.2 million or more, 1.5 million or more, 1.8 million or more, or even 2 million or more. The upper limit of Mw is, for example, 3 million or less.

[0048] The molecular weight distribution (Mw / number average molecular weight (Mn)) of the (meth)acrylic polymer is, for example, 2 to 20, and may be 4 to 15. In this specification, the Mw and Mn of the polymer and oligomer are values ​​(polystyrene equivalent) based on measurements by GPC (gel permeation chromatography).

[0049] The content of the (meth)acrylic polymer in the pressure-sensitive adhesive composition may be, for example, 50% by weight or more, 60% by weight or more, or even 70% by weight or more, in terms of solid content.

[0050] <(Meth)acrylic oligomer> The pressure-sensitive adhesive composition may further contain a (meth)acrylic oligomer.

[0051] The (meth)acrylic oligomer may have the same composition as the above-mentioned (meth)acrylic polymer, except for its different Mw. The Mw of the (meth)acrylic oligomer may be, for example, 1,000 or more, 2,000 or more, 3,000 or more, or even 4,000 or more. The upper limit of the Mw of the (meth)acrylic oligomer may be, for example, 30,000 or less, 15,000 or less, 10,000 or less, or even 7,000 or less.

[0052] The (meth)acrylic oligomer 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, alkyl (meth)acrylates such as methyl (meth)acrylate, nonyl (meth)acrylate, isononyl (meth)acrylate, decyl (meth)acrylate, isodecyl (meth)acrylate, undecyl (meth)acrylate, and dodecyl (meth)acrylate; esters of (meth)acrylic acid and alicyclic alcohols such as cyclohexyl (meth)acrylate, isobornyl (meth)acrylate, and dicyclopentanyl (meth)acrylate; aryl (meth)acrylates such as phenyl (meth)acrylate and benzyl (meth)acrylate; and (meth)acrylates obtained from terpene compound-derived alcohols.

[0053] The (meth)acrylic oligomer may have a structural unit derived from an acrylic monomer having a relatively bulky structure. Examples of the acrylic monomer include alkyl (meth)acrylates having an alkyl group with a branched structure, such as isobutyl (meth)acrylate and t-butyl (meth)acrylate; esters of (meth)acrylic acid and alicyclic alcohol, such as cyclohexyl (meth)acrylate, isobornyl (meth)acrylate, and dicyclopentanyl (meth)acrylate; and aryl (meth)acrylates, such as phenyl (meth)acrylate and benzyl (meth)acrylate. The acrylic monomer preferably has a cyclic structure, and more preferably has two or more cyclic structures. Furthermore, when ultraviolet irradiation is carried out during polymerization of the (meth)acrylic oligomer and / or during formation of the pressure-sensitive adhesive composition, the acrylic monomer preferably does not have an unsaturated bond, since this makes it difficult for the progress of polymerization and / or formation to be inhibited. 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.

[0054] Specific examples of the (meth)acrylic oligomer include a copolymer of butyl acrylate, methyl acrylate, and acrylic acid, a copolymer of cyclohexyl methacrylate and isobutyl methacrylate, a copolymer of cyclohexyl methacrylate and isobornyl methacrylate, a copolymer of cyclohexyl methacrylate and acryloylmorpholine, a copolymer of cyclohexyl methacrylate and diethylacrylamide, a copolymer of 1-adamantyl acrylate and methyl methacrylate, a copolymer of dicyclopentanyl methacrylate and isobornyl methacrylate, a copolymer of methyl methacrylate and at least one selected from dicyclopentanyl methacrylate, cyclohexyl methacrylate, isobornyl methacrylate, isobornyl acrylate, and cyclopentanyl methacrylate, a homopolymer of dicyclopentanyl acrylate, a homopolymer of 1-adamantyl methacrylate, and a homopolymer of 1-adamantyl acrylate.

[0055] The polymerization method for the (meth)acrylic oligomer can be the same as the polymerization method for the (meth)acrylic polymer described above.

[0056] When the pressure-sensitive adhesive composition contains a (meth)acrylic oligomer, the blending amount thereof may be, for example, 70 parts by weight or less, 50 parts by weight or less, or even 40 parts by weight or less, relative to 100 parts by weight of the (meth)acrylic polymer. The lower limit of the blending amount may be, for example, 0.05 parts by weight or more, 0.1 parts by weight or more, or even 0.2 parts by weight or more, relative to 100 parts by weight of the (meth)acrylic polymer. The pressure-sensitive adhesive composition does not have to contain a (meth)acrylic oligomer.

[0057] The (meth)acrylic oligomer can be used in both solvent-based and active energy ray-curable pressure-sensitive adhesive compositions. However, when the (meth)acrylic oligomer is dissolved in a solvent and used in an active energy ray-curable pressure-sensitive adhesive composition, the solvent may be removed from the mixture containing the (meth)acrylic oligomer by, for example, heat drying, and then curing may be promoted by irradiation with active energy rays.

[0058] <Crosslinking agent> The pressure-sensitive adhesive composition may further contain a crosslinking agent. Use of a crosslinking agent can improve the cohesive strength of the pressure-sensitive adhesive composition.

[0059] Examples of crosslinking agents include organic crosslinking agents and polyfunctional metal chelates. Examples of organic crosslinking agents include isocyanate-based crosslinking agents, peroxide-based crosslinking agents, epoxy-based crosslinking agents, and imine-based crosslinking agents. Polyfunctional metal chelates have a structure in which a polyvalent metal is covalently or coordinately bonded to an organic compound. Examples of polyvalent metals include Al, Cr, Zr, Co, Cu, Fe, Ni, V, Zn, In, Ca, Mg, Mn, Y, Ce, Sr, Ba, Mo, La, Sn, and Ti. The atom in the organic compound to which the polyvalent metal is covalently or coordinately bonded is typically an oxygen atom. Examples of organic compounds include alkyl esters, alcohol compounds, carboxylic acid compounds, ether compounds, and ketone compounds. Organic crosslinking agents and polyfunctional metal chelates can be used in both solvent-based and active energy ray-curable pressure-sensitive adhesive compositions.

[0060] When the pressure-sensitive adhesive composition is a solvent-based composition, the crosslinking agent is preferably an isocyanate-based crosslinking agent or a peroxide-based crosslinking agent. The isocyanate-based crosslinking agent may be bifunctional or trifunctional. However, in order to maintain cohesive strength at high temperatures, a trifunctional crosslinking agent is preferred. A trifunctional crosslinking agent forms a three-dimensional crosslinked structure. An isocyanate-based crosslinking agent and a peroxide-based crosslinking agent may also be used in combination. This combination can further improve adhesive strength while maintaining cohesive strength at high temperatures. The isocyanate-based crosslinking agent used in combination is preferably trifunctional.

[0061] When the pressure-sensitive adhesive composition contains a crosslinking agent, the amount thereof is, for example, 0.01 to 10 parts by weight, or may be 0.1 to 5 parts by weight, or even 0.1 to 3 parts by weight, relative to 100 parts by weight of the (meth)acrylic polymer.

[0062] When an isocyanate-based crosslinking agent is used alone, the amount thereof is, for example, 0.01 to 3 parts by weight, or may be 0.01 to 1 part by weight, 0.01 to 0.5 parts by weight, or even 0.01 to 0.3 parts by weight, relative to 100 parts by weight of the (meth)acrylic polymer.

[0063] When an isocyanate-based crosslinking agent and a peroxide-based crosslinking agent are used in combination, the weight ratio of the peroxide-based crosslinking agent to the isocyanate-based crosslinking agent is, for example, 1.0 or more, and may be 1.2 or more, 1.5 or more, or even 2 or more. The upper limit of the weight ratio is, for example, 500 or less, 300 or less, or may even be 200 or less.

[0064] <Additives> The pressure-sensitive adhesive composition may contain other additives. Examples of additives include silane coupling agents other than the Si agent (X), silicone compounds (excluding silane coupling agents) such as silicone oil, polyether compounds (such as polyalkylene glycols including polypropylene glycol), colorants such as pigments and dyes, surfactants, plasticizers, tackifiers, surface lubricants, leveling agents, softeners, antioxidants, antiaging agents, light stabilizers, UV absorbers, polymerization inhibitors, antistatic agents (such as alkali metal salts, ionic liquids, and ionic solids, which are ionic compounds), inorganic fillers, organic fillers, powders such as metal powders, particles, and foil-like materials. When a silane coupling agent other than the Si agent (X) is contained, the content of the silane coupling agent may be 0.5 wt. % or less, 0.1 wt. % or less, 0.05 wt. % or less, or even less than 0.01 wt. The pressure-sensitive adhesive composition may not contain any silane coupling agents other than the Si agent (X). When a silicone compound is contained, the content of the silicone compound may be 0.5 wt % or less, 0.1 wt % or less, 0.05 wt % or less, or even less than 0.01 wt %. The pressure-sensitive adhesive composition may not contain a silicone compound.

[0065] [Adhesive layer] The thickness of the pressure-sensitive adhesive layer 2 is, for example, 1 to 200 μm, and may be 5 to 150 μm, or even 10 to 100 μm. The pressure-sensitive adhesive layer 2 may be a single layer or a laminate containing two or more layers. All of the two or more layers may contain the pressure-sensitive adhesive composition.

[0066] The 800% modulus of the pressure-sensitive adhesive layer 2 at 80°C is, for example, 0.18 to 0.5 N / mm 2 and 0.2 to 0.4 N / mm 2, and even 0.2 to 0.3 N / mm 2 The 800% modulus is a property represented by the value obtained by dividing the stress (tensile stress) generated in the pressure-sensitive adhesive layer 2 when the pressure-sensitive adhesive layer 2 is elongated by 800% by a tensile force in one direction by the initial cross-sectional area of ​​the pressure-sensitive adhesive layer 2. The 800% modulus of the pressure-sensitive adhesive layer 2 can be evaluated as follows.

[0067] The pressure-sensitive adhesive layer 2 to be evaluated is cut into a 30 mm x 100 mm strip. Next, the cut pressure-sensitive adhesive layer 2 is rolled in the direction of the long side to prevent air bubbles from being trapped, to obtain a cylindrical test piece with a height of 30 mm corresponding to the length of the short side. The obtained test piece is then placed in a tensile tester such as a Tensilon, and a uniaxial tensile test is performed in the height direction to obtain an elongation-stress curve of the pressure-sensitive adhesive layer 2. The preparation of the test piece and the uniaxial tensile test are performed at 23°C, with an initial chuck distance of 10 mm and a tensile speed of 300 mm / min. From the obtained elongation-stress curve, the stress at 800% elongation (when the chuck distance is 90 mm) is calculated, and this is divided by the initial cross-sectional area of ​​the test piece to obtain the 800% modulus of the pressure-sensitive adhesive layer 2.

[0068] The adhesive strength of the pressure-sensitive adhesive layer 2 to a polyethylene terephthalate (PET) film at 80°C is, for example, 1.8 N / 25 mm or more, and may be 2.0 N / 25 mm or more, 2.5 N / 25 mm or more, 2.7 N / 25 mm or more, 3.0 N / 25 mm or more, 3.2 N / 25 mm or more, or even 3.5 N / 25 mm or more. The upper limit of the adhesive strength is, for example, 10.0 N / 25 mm or less. However, the adhesive strength is evaluated in a state where the pressure-sensitive adhesive layer 2 is placed on the modified surface of the PET film. In other words, the adhesive strength is the adhesive strength to the modified surface of the PET film.

[0069] The total light transmittance (according to JIS K7136) of the pressure-sensitive adhesive layer 2 in the visible light wavelength region is preferably 85% or more, more preferably 90% or more.

[0070] The pressure-sensitive adhesive composition described above is a pressure-sensitive adhesive composition that is disposed on the modified surface 12 of the optical substrate 1 in the optical laminate 1. From this aspect, the present invention provides: In the optical laminate 1, a pressure-sensitive adhesive composition is disposed on the surface 11 of the optical substrate 1, Contains a silane coupling agent, The silane coupling agent contains an isocyanuric ring but does not contain an isocyanate group, a pressure-sensitive adhesive composition, wherein the surface on which the pressure-sensitive adhesive composition is placed is a modified surface that has been surface-modified by energy irradiation; to provide.

[0071] [Formation of adhesive layer] The pressure-sensitive adhesive layer 2 can be formed, for example, by the following method. A solvent-based pressure-sensitive adhesive composition is applied to a separator (release film) or the like, and the polymerization solvent, etc. is removed by drying. The pressure-sensitive adhesive layer 2 formed on the separator can be transferred to the surface 11 of the optical substrate 1. The active energy ray-curable pressure-sensitive adhesive composition is applied to a separator or the like and cured by irradiating with active energy rays. In addition to irradiating with active energy rays, drying by heating may be performed. Furthermore, when applying the pressure-sensitive adhesive composition, one or more solvents other than the polymerization solvent may be newly added to the composition.

[0072] The surface of the separator to which the pressure-sensitive adhesive composition is applied may be subjected to a release treatment, for example, a silicone treatment using a silicone compound.

[0073] The drying temperature is, for example, 40 to 200° C., and may be 50 to 180° C., or even 70 to 170° C. However, this can be adjusted depending on the composition of the pressure-sensitive adhesive composition, etc.

[0074] The drying time is, for example, 5 seconds to 20 minutes, or may be 5 seconds to 10 minutes, or even 10 seconds to 5 minutes, although this can be adjusted depending on the composition of the adhesive composition, etc.

[0075] The pressure-sensitive adhesive composition can be applied by, 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, or extrusion coating using a die coater or the like.

[0076] [Optical base material] The optical substrate 1 has a modified surface 12. The modified surface 12 is a surface that has been modified by energy irradiation. In the surface modification, functional groups are generated on the surface of the substrate. The surface modification by energy irradiation is, for example, at least one treatment selected from corona treatment, plasma treatment, and ultraviolet treatment (excimer laser irradiation, etc.).

[0077] The energy irradiation can be carried out, for example, in an atmosphere containing an inert gas such as nitrogen or in air. The amount of energy to be irradiated is, for example, 0.05 to 20 J / cm. 2 and 0.1 to 5 J / cm 2 For the energy irradiation in each treatment, a known method can be applied.

[0078] The optical substrate 1 may be made of a resin, in other words, a resin substrate. In this case, the Si agent (X) may be unevenly distributed in a region 21 in the pressure-sensitive adhesive layer 2 near the interface 3 with the optical substrate 1. However, the optical substrate 1 is not limited to a resin substrate. Examples of resins constituting the optical substrate 1 include polyesters such as PET, acrylic resins, polyolefins, polycycloolefins, polyimides, polyurethanes, and modified celluloses such as triacetyl cellulose (TAC). The acrylic resin may have a ring structure such as an amide ring, an imide ring, an acid anhydride ring, or a lactone ring. However, the resin is not limited to the above examples.

[0079] Examples of the optical substrate 1 include polarizing films, polarizer protective films, retardation films, optical compensation films such as viewing angle compensation films, antireflection films, antistatic films, conductive films, cushion films, decorative films, cover windows, image forming layers such as liquid crystal layers and organic EL light-emitting layers, and laminates thereof. However, the optical substrate 1 is not limited to the above examples and may be, for example, any optical substrate used in image display devices.

[0080] The polarizing film includes a polarizer. A polarizer protective film may be bonded to at least one surface of the polarizer via a pressure-sensitive adhesive layer. The polarizer is typically a polyvinyl alcohol (PVA) film in which iodine has been oriented by various methods, such as a stretching method such as in-air stretching (dry stretching) or stretching in boric acid water, or a coating method.

[0081] A retardation film is a film having birefringence in the in-plane direction and / or the thickness direction, and is, for example, a stretched resin film or a film in which a liquid crystal material is oriented and fixed.

[0082] Examples of the retardation film include a λ / 4 plate, a λ / 2 plate, an anti-reflection retardation film (see, for example, paragraphs 0221, 0222, and 0228 of JP 2012-133303 A), a viewing angle compensation retardation film (see, for example, paragraphs 0225 and 0226 of JP 2012-133303 A), and an obliquely oriented viewing angle compensation retardation film (see, for example, paragraph 0227 of JP 2012-133303 A). However, 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, arrangement angle, three-dimensional birefringence, whether the retardation film is single-layer or multi-layer, and the like of the retardation film are also not limited. The retardation film may be a known film.

[0083] The thickness of the retardation film is, for example, 50 μm or less, and may be 20 μm or less, 10 μm or less, or even 1 to 9 μm.

[0084] The thickness of the optical substrate 1 is, for example, 1 μm or more, and may be 5 μm or more, or even 25 μm or more. The upper limit of the thickness of the optical substrate 1 is, for example, 200 μm or less.

[0085] The total light transmittance (according to JIS K7136) of the optical substrate 1 in the visible light wavelength region is preferably 85% or more, more preferably 90% or more.

[0086] The total light transmittance (according to JIS K7136) of the optical laminate 100 in the visible light wavelength region is preferably 85% or more, and more preferably 90% or more.

[0087] 1 includes one optical substrate 1 and one pressure-sensitive adhesive layer 2. The optical laminate of the present invention may include two or more optical substrates 1 and / or two or more pressure-sensitive adhesive layers 2. In other words, the optical laminate of the present invention includes at least one optical substrate 1 and at least one pressure-sensitive adhesive layer 2.

[0088] The optical laminate 110 in FIG. 2 includes a retardation film 4, polarizer protective films 5A and 5B, a polarizer 6, and pressure-sensitive adhesive layers 7A, 7B, and 7C. In the optical laminate 110, the retardation film 4, the pressure-sensitive adhesive layer 7A, the polarizer protective film 5A, the pressure-sensitive adhesive layer 7B, the polarizer 6, the pressure-sensitive adhesive layer 7C, and the polarizer protective film 5B are laminated in this order. At least one pressure-sensitive adhesive layer selected from the three pressure-sensitive adhesive layers 7A, 7B, and 7C is the pressure-sensitive adhesive layer 2 described above. All of the pressure-sensitive adhesive layers 7A, 7B, and 7C may be the pressure-sensitive adhesive layers 2. Furthermore, at least one of the optical substrates in contact with the pressure-sensitive adhesive layer 2 may be the optical substrate 1 described above. Both of the optical substrates in contact with the pressure-sensitive adhesive layer 2 may be the optical substrate 1 described above.

[0089] When the optical laminate 110 has two or more pressure-sensitive adhesive layers 2, the pressure-sensitive adhesive compositions contained in the pressure-sensitive adhesive layers 2 may be the same or different from each other.

[0090] The optical laminate of the present invention may be an optical substrate with a pressure-sensitive adhesive layer that is attached to another member when used.

[0091] An example of an optical substrate with a pressure-sensitive adhesive layer is shown in Figure 3. The optical substrate 120 with a pressure-sensitive adhesive layer in Figure 3 comprises an optical substrate 1, a pressure-sensitive adhesive layer 2, and a separator 8 arranged on the surface of the pressure-sensitive adhesive layer 2 opposite to the surface to which the optical substrate 1 is bonded. The separator 8 has the function of protecting the pressure-sensitive adhesive layer 2 during distribution and storage of the optical substrate 120 with a pressure-sensitive adhesive layer, and is peeled off when the optical substrate 120 with a pressure-sensitive adhesive is used.

[0092] The separator 8 is typically a resin film. Examples of resins constituting the separator 8 include polyesters such as PET, polyolefins such as polyethylene and polypropylene, polycarbonate, acrylic resins, polystyrene, polyamide, and polyimide. The surface of the separator 8 that comes into contact with the pressure-sensitive adhesive layer 2 may be subjected to a release treatment. The release treatment is, for example, a silicone treatment using a silicone compound. However, the separator 8 is not limited to the above examples.

[0093] The thickness of the separator 8 is, for example, 20 μm to 100 μm.

[0094] The pressure-sensitive adhesive optical substrate 120 may include two or more optical substrates 1 and / or two or more pressure-sensitive adhesive layers 2. In the pressure-sensitive adhesive optical substrate 120 including two or more pressure-sensitive adhesive layers, at least one of the pressure-sensitive adhesive layers may be the pressure-sensitive adhesive layer 2 described above.

[0095] The optical layered body of the present invention may include any layer other than those described above.

[0096] The optical laminate of the present invention can be distributed and stored, for example, in the form of a sheet or a roll obtained by rolling up a strip-shaped laminate.

[0097] The optical layered body of the present invention may be used for an image display device.

[0098] [Image display device] An example of an image display device is shown in Fig. 4. The image display device 200 in Fig. 4 has a layered structure in which a substrate 51, a pressure-sensitive adhesive layer 10A, an image-forming layer (organic EL layer) 52, a pressure-sensitive adhesive layer 10B, an optical substrate 1, a pressure-sensitive adhesive layer 2, and a cover film 53 are layered in this order. The image display device 200 includes an optical laminate 100. The substrate 51, the image-forming layer 52, and the cover film 53 may have the same configurations as the substrate, the image-forming layer, and the cover film, respectively, that are included in known organic EL displays.

[0099] At least one selected from the pressure-sensitive adhesive layers 10A and 10B may be the above-mentioned pressure-sensitive adhesive layer 2. In this case, at least one member in contact with the pressure-sensitive adhesive layers 10A and 10B, which are the pressure-sensitive adhesive layers 2, is the optical substrate 1.

[0100] 4 is an organic EL display, but the image display device 8 of the present invention is not limited to the above example.

[0101] The image display device 200 may have any configuration as long as it includes the optical laminate of the present invention.

[0102] The image display device 200 may be a flexible image display device. [Example]

[0103] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to the examples shown below.

[0104] The correspondence between the abbreviations or names shown in the following explanation and the compounds is as follows: BA: butyl acrylate HBA: Hydroxybutyl acrylate 2EHA: 2-ethylhexyl acrylate NVP: N-vinylpyrrolidone D110N: Trimethylolpropane / xylylene diisocyanate adduct (Mitsui Chemicals Takenate D110N, isocyanate-based crosslinking agent) BPO: Benzoyl peroxide (peroxide-based crosslinking agent) KBM9659: Tris-(trimethoxysilylpropyl) isocyanurate (Shin-Etsu Chemical, Si agent (X)) KBM403: 3-glycidoxypropyltrimethoxysilane (Shin-Etsu Chemical Co., Ltd., a silane coupling agent with an epoxy group at the end) KBM573: N-phenyl-3-aminopropyltrimethoxysilane (Shin-Etsu Chemical Co., Ltd., a silane coupling agent with an amino group)

[0105] [Preparation of (meth)acrylic polymer] (Synthesis Example 1) A four-neck flask equipped with a stirring blade, thermometer, nitrogen gas inlet, and condenser was charged with 99 parts by weight of BA and 1 part by weight of HBA, and the mixture was diluted with ethyl acetate and toluene to a concentration of 50% by weight. The toluene content of the solvent used for dilution was 5% by weight. Next, 0.1 parts by weight of AIBN as a polymerization initiator was added to 100 parts by weight of the BA and HBA mixture. Nitrogen gas was introduced with gentle stirring to replace the atmosphere in the flask. The liquid temperature in the flask was maintained at around 55°C, and the polymerization reaction was allowed to proceed for 7 hours. Ethyl acetate was then added to the resulting reaction solution to adjust the solids concentration to 20% by weight, yielding a solution of (meth)acrylic polymer A1. The Mw of (meth)acrylic polymer A1 was 1.8 million. The Mw of the (meth)acrylic polymers prepared in each synthesis example was measured by GPC under the following measurement conditions. Analytical equipment: Waters, Acquity APC Column: Tosoh G7000HXL+GMHXL+GMHXL Column temperature: 40℃ Eluent: tetrahydrofuran (acid added) ·Flow rate: 0.8mL / min ·Injection volume: 100μL Detector: Differential refractometer (RI) Standard sample: Agilent, polystyrene (PS)

[0106] (Synthesis Example 2) A solution of (meth)acrylic polymer A2 was obtained in the same manner as in Synthesis Example 1, except that 96 parts by weight of 2EHA, 1 part by weight of HBA, and 3 parts by weight of NVP were charged into a flask and the proportion of toluene in the solvent used for dilution was 30% by weight. The Mw of (meth)acrylic polymer A2 was 1,200,000.

[0107] (Synthesis Example 3) A solution of (meth)acrylic polymer A3 was obtained in the same manner as in Synthesis Example 2, except that the proportion of toluene in the solvent used for dilution was 5% by weight. The Mw of (meth)acrylic polymer A3 was 2,000,000.

[0108] (Synthesis Example 4) A solution of (meth)acrylic polymer A4 was obtained in the same manner as in Synthesis Example 2, except that the proportion of toluene in the solvent used for dilution was 0 wt%, the amount of polymerization initiator was 0.05 parts by weight of AIBN, and the polymerization reaction time was 2 hours. The Mw of (meth)acrylic polymer A4 was 2,800,000.

[0109] The (meth)acrylic polymers prepared in each synthesis example are summarized in Table 1 below.

[0110] [Table 1]

[0111] [Preparation of Pressure-Sensitive Adhesive Composition] Solvent-based pressure-sensitive adhesive compositions P1 to P11 were obtained by mixing a (meth)acrylic polymer solution, a crosslinking agent, and a silane coupling agent to obtain the compositions shown in Table 2. The contents of the polymer, crosslinking agent, and silane coupling agent are values ​​calculated as solid contents.

[0112] [Table 2]

[0113] [Preparation of optical laminate] Example 1 The pressure-sensitive adhesive composition P1 thus prepared was applied to the release-treated surface of a release film (Mitsubishi Plastics, MRF#38) using a fountain coater, and then dried for 2 minutes in an air-circulating thermostatic oven set at 155°C to form a layer of the pressure-sensitive adhesive composition (thickness 20 μm). Separately, a corona treatment (irradiation energy: 0.3 J / cm) was performed in air. 2 A PET film (75 μm thick) having a modified surface was prepared as an optical substrate. The layer of the pressure-sensitive adhesive composition formed above was attached to the modified surface of the prepared PET film to produce an optical laminate comprising a pressure-sensitive adhesive layer and an optical substrate. The attachment was performed so that the portion not in contact with the pressure-sensitive adhesive layer was formed with a width of 50 mm or more from one side of the PET film.

[0114] Examples 2 to 9 Optical laminates of Examples 2 to 9 were obtained in the same manner as in Example 1, except that pressure-sensitive adhesive compositions P2 to P9 were used instead of pressure-sensitive adhesive composition P1, respectively.

[0115] (Comparative Example 1) An optical laminate of Comparative Example 1 was obtained in the same manner as in Example 1, except that adhesive composition P3 was used instead of adhesive composition P1 and a PET film (same thickness) without a modified surface was used as the optical substrate.

[0116] (Comparative Example 2) An optical laminate of Comparative Example 2 was obtained in the same manner as in Example 1, except that adhesive composition P10 was used instead of adhesive composition P1 and a PET film (same thickness) without a modified surface was used as the optical substrate.

[0117] (Comparative Example 3) An optical laminate of Comparative Example 3 was obtained in the same manner as in Example 1, except that the pressure-sensitive adhesive composition P10 was used instead of the pressure-sensitive adhesive composition P1.

[0118] Comparative Example 4 An optical laminate of Comparative Example 4 was obtained in the same manner as in Example 1, except that the pressure-sensitive adhesive composition P11 was used instead of the pressure-sensitive adhesive composition P1.

[0119] [evaluation] [Whether or not the Si agent (X) is unevenly distributed] The optical laminates of Example 3 and Comparative Example 1 were evaluated by TOF-SIMS in combination with etching ions to determine whether or not the Si agent (X) was unevenly distributed in the pressure-sensitive adhesive layer. This evaluation method allows elemental analysis in the thickness direction of the pressure-sensitive adhesive layer. The TOF-SIMS evaluation conditions were as follows: ·Equipment: Manufactured by ULVAC-PHI, TRIFT-V · Evaluation target: SiOH + m / z=45 corresponds to the ion Etching ions: Ar gas cluster ions Etching ion acceleration voltage: 10kV Irradiated primary ions: Bi3 2+ Primary ion acceleration voltage: 30 kV Etching from the exposed surface of the adhesive layer towards the optical substrate

[0120] The evaluation results for each optical laminate of Example 3 and Comparative Example 1 are shown in Figures 5A and 5B, respectively. In the plots of Figures 5A and 5B, the horizontal axis represents the etching time (unit: seconds), and the vertical axis represents the C2H3 + SiOH normalized based on ion intensity + 5A, in the optical laminate of Example 3, it was confirmed that the Si agent (X) was unevenly distributed in a region 21 in the pressure-sensitive adhesive layer near the interface with the PET film (hatched area). In the plot of FIG. 5A, the SiOH + The sum of the peak areas is the measurable SiOH in the adhesive layer. + The sum of the peak areas was 90% or more. On the other hand, as shown in FIG. 5B, in the optical laminate of Comparative Example 1, uneven distribution of the Si agent (X) was not observed. It was confirmed that uneven distribution of the Si agent (X) occurs due to the combination of the Si agent (X) and the modified surface of the optical substrate. In addition, in the plots of each figure, SiOH + The intensity of the ion is relatively large. This is because the normalization standard C2H3 +This is thought to be because the ionic strength is much weaker in the PET film than in the pressure-sensitive adhesive layer containing a (meth)acrylic polymer.

[0121] [800% modulus] The 800% modulus of the adhesive layer was evaluated as follows. The adhesive layer formed on a release film was cut into a rectangle 30 mm wide and 100 mm long, and rolled up to form a cylindrical shape without trapping any air bubbles, to prepare a measurement sample. The stress at 800% elongation was determined from the elongation-stress curve of the measurement sample measured using a tensile tester under conditions of an initial chuck distance of 10 mm and a pulling speed of 300 mm / min, and the 800% modulus (N / mm 2 ) was calculated. Note that 800% elongation refers to the state where the distance between chucks is 90 mm. The tensile tester used was an Autograph AG-IS manufactured by Shimadzu Corporation. The evaluation was carried out at room temperature (23°C).

[0122] [High temperature adhesive strength] The high-temperature (80°C) adhesive strength of the pressure-sensitive adhesive layer to the optical substrate was evaluated as follows. An additional PET film (75 μm thick) that had been subjected to the same corona treatment as described above was bonded to the optical laminate prepared in each Example and Comparative Example. The laminate obtained by bonding was then cut into strips 25 mm wide and 150 mm long to obtain measurement samples. The bonding was performed so that the pressure-sensitive adhesive layer of the optical laminate and the modified surface of the additional PET film were in contact with each other, and so that, when cut into strips, the additional PET film had a first free end (50 mm long) at one end of the long side of the laminate that was not in contact with the pressure-sensitive adhesive layer. During bonding, a pressure roller with a mass of 2 kg as specified in Japanese Industrial Standards (formerly Japanese Industrial Standards; JIS) Z0237:2009 was reciprocated at a temperature of 25°C. The cutting was performed so that the portion of the optical substrate that was not in contact with the pressure-sensitive adhesive layer when the optical laminate was prepared was positioned at the other end of the long side as the second free end (50 mm long). The measurement sample was then left to stand for 30 minutes and set in a tensile tester equipped with a thermostatic chamber. The setting was performed so that one chuck of the tester gripped the first free end and the other chuck gripped the second free end. Next, the environmental temperature of the tester and the test sample was controlled to the evaluation temperature (80°C). After the environmental temperature reached the evaluation temperature and the sample was left to stand for 5 minutes, a peel test was performed by pulling both free ends in opposite directions at a test speed of 300 mm / min. After the start of the test, the initial measurement value (stress value) measured until the pulling distance (expansion distance between the chucks) reached 10 mm from the initial state was ignored, and the average of the stress values ​​measured until the pulling distance from the initial state reached 80 mm was taken as the high-temperature adhesive strength.

[0123] The evaluation results for each of the optical laminates of the Examples and Comparative Examples are shown in Table 3 below.

[0124] [Table 3]

[0125] As shown in Table 3, in the optical laminates of the examples, the high-temperature adhesive strength was improved while the cohesive strength of the pressure-sensitive adhesive layer was maintained. Note that when the pressure-sensitive adhesive composition contained a silane coupling agent having an epoxy group at its terminal, the degree of improvement in high-temperature adhesive strength due to surface modification of the PET film was small (Comparative Examples 2 and 3). [Industrial Applicability]

[0126] The optical layered body of the present invention can be used, for example, in an image display device. [Explanation of symbols]

[0127] 1 Optical substrate 11 Surface 12 Modified Surface 2. Adhesive layer 21 areas 3 Interface 51 Image forming layer 100,110,120 optical laminate 200 Image display device

Claims

1. An optical substrate and a pressure-sensitive adhesive layer disposed on a surface of the optical substrate, the pressure-sensitive adhesive layer comprises a pressure-sensitive adhesive composition containing a silane coupling agent, The silane coupling agent contains an isocyanuric ring but does not contain an isocyanate group, An optical laminate, wherein the surface on which the pressure-sensitive adhesive layer is disposed is a modified surface that has been surface-modified by energy irradiation.

2. The optical laminate according to claim 1 , wherein the silane coupling agent is unevenly distributed in a region of the pressure-sensitive adhesive layer near the interface with the optical substrate.

3. The optical laminate according to claim 1 or 2, wherein the content of the silane coupling agent in the pressure-sensitive adhesive composition is 0.05% by weight or more and 1.0% by weight or less.

4. The optical laminate according to any one of claims 1 to 3, wherein the optical substrate is made of a resin.

5. The optical laminate according to any one of claims 1 to 4, wherein the pressure-sensitive adhesive composition contains a (meth)acrylic polymer.

6. The optical laminate according to claim 5 , wherein the (meth)acrylic polymer has a weight average molecular weight of 1,800,000 or more.

7. 7. The optical laminate according to claim 1, wherein the surface modification by energy irradiation is at least one treatment selected from the group consisting of corona treatment, plasma treatment, and ultraviolet treatment.

8. The optical laminate according to any one of claims 1 to 7, An image display device comprising: an image forming layer.

9. In the optical laminate according to any one of claims 1 to 7, a pressure-sensitive adhesive composition is disposed on a surface of an optical substrate, Contains a silane coupling agent, The silane coupling agent contains an isocyanuric ring but does not contain an isocyanate group, A pressure-sensitive adhesive composition, wherein the surface on which the pressure-sensitive adhesive composition is placed is a modified surface that has been surface-modified by energy irradiation.

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