JP2007119667A - Adhesive - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an adhesive not causing a change in appearance of optical laminate and excellent in durability when repeating heating and cooling under high-moisture conditions and high-heat conditions. <P>SOLUTION: The adhesive is characterized in that THF insoluble content X(%) of the adhesive and Y(%) represented by formula (III): Y=B-(100-X)×C/100 satisfy formula (I): 40≤X≤70 and formula (II): -0.51X+41<Y<0.45X+24 (wherein B represents wt.% of a component having ≥300,000 molecular weight in a mixture of an acrylic resin (1) having 50,000-250,000 weight-average molecular weight with an acrylic resin (2) containing a monomer (b) containing a polar functional group and an olefinic double bond and having 1,000,000-1,500,000 weight-average molecular weight; C is wt.% of a component having ≥300,000 molecular weight in a content of the adhesive which is soluble in THF), in the adhesive composed of these acrylic resins (1) and (2). <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a pressure-sensitive adhesive and an optical laminate including the pressure-sensitive adhesive.

A liquid crystal cell generally used in a liquid crystal display device such as a TFT or STN has a structure in which a liquid crystal component is sandwiched between two glass substrates. And on the surface of this glass base material, optical films, such as a polarizing film and retardation film, are laminated | stacked through the adhesive which has an acrylic resin as a main component. And the optical laminated body formed by laminating a glass substrate, a pressure-sensitive adhesive and an optical film in order is first to produce an optical film with a pressure-sensitive adhesive obtained by laminating the pressure-sensitive adhesive on the optical film, and then the surface of the pressure-sensitive adhesive A method of laminating a glass substrate is generally used.
Such an optical film with pressure-sensitive adhesive tends to cause curling or the like because of a large dimensional change due to expansion or contraction under heat or wet heat conditions, and foams within the pressure-sensitive adhesive layer of the obtained optical laminate, or the pressure-sensitive adhesive layer and the glass substrate. There was a problem that floating, peeling, etc. occurred between the materials. Further, the distribution of residual stress acting on the optical film with adhesive becomes non-uniform under heat or wet heat conditions, resulting in stress concentration at the outer periphery of the optical laminate, resulting in white spots in the TN liquid crystal cell (TFT), STN liquid crystal There was a problem that color unevenness occurred in the cell.
In order to solve such problems, Patent Document 1 proposes an adhesive mainly composed of a high molecular weight acrylic resin having a weight average molecular weight of 600,000 to 2,000,000 and a low molecular weight acrylic resin having a weight average molecular weight of 500,000 or less.

JP 2000-109771 A [Claim 1]

Recently, attempts have been made to use liquid crystal display devices for in-car use such as car navigation systems, but in-vehicle use does not cause changes in appearance such as foaming, floating, peeling, and clouding even under high temperature and high humidity conditions. Durability has also become necessary.
The present inventors have obtained an optical film obtained by laminating an optical film on an adhesive obtained by crosslinking a composition of a high molecular weight acrylic resin and a low molecular weight acrylic resin satisfying the conditions described in the above-mentioned patent documents with a crosslinking agent. Examination of the laminate revealed that the durability under white spots, high humidity conditions and high heat conditions may not be satisfied.
The object of the present invention is to suppress white spots of the optical laminate and to float or peel between the glass substrate and the adhesive layer in the optical laminate under high humidity conditions or high heat conditions. Adhesive with excellent durability that suppresses foaming in the layer and has almost no change in appearance such as white spots, floating, peeling, foaming, and clouding even after repeated heating and cooling; the adhesive and optical film And an optical laminate formed by laminating an optical film and a glass substrate via an adhesive layer of the optical film with an adhesive.

Under such circumstances, as a result of intensive studies on the pressure-sensitive adhesive, the present inventors have found that a specific pressure-sensitive adhesive can solve this problem, and completed the present invention.
That is, the present invention is represented by the weight percentage X (%) of the tetrahydrofuran-insoluble content in the pressure-sensitive adhesive obtained by crosslinking the following acrylic resins (1) and (2) with a crosslinking agent, and the formula (III). A pressure-sensitive adhesive wherein the weight percentage Y (%) of the high molecular weight component in the tetrahydrofuran-insoluble content of the adhesive satisfies the formulas (I) and (II); the adhesive on both or one side of the optical film An optical laminated body obtained by laminating a glass substrate on the pressure-sensitive adhesive layer of the optical film with pressure-sensitive adhesive.

40 ≦ X ≦ 70 (I)
-0.51X + 41 <Y <0.45X + 24 (II)
Y = B- (100-X) * C / 100 (III)
(In the formula, X represents the weight percentage (%) of the tetrahydrofuran insoluble to the adhesive, B represents the weight percentage of the component having a molecular weight of 300,000 or more in the mixture of the acrylic resins (1) and (2), and C is (Represents the weight percentage of components with a molecular weight of 300,000 or more in the tetrahydrofuran dissolved content of the adhesive.)

（式中、Ｒ_１は水素原子またはメチル基を表し、Ｒ_２は炭素数１〜１４のアルキル基またはアラルキル基を表す。Ｒ_２のアルキル基の水素原子またはアラルキル基の水素原子は炭素数１〜１０のアルコキシ基によって置換されていてもよい。） Acrylic resin (1): Main component is a structural unit (structural unit (a)) derived from the following monomer (a)
An acrylic resin having a weight average molecular weight of 50,000 to 250,000.
(A): (Meth) acrylic acid ester represented by formula (A)

(In the formula, R ₁ represents a hydrogen atom or a methyl group, R ₂ represents an alkyl group or an aralkyl group having 1 to 14 carbon atoms. The hydrogen atom of the alkyl group or the aralkyl group of R ₂ has 1 carbon atom. Optionally substituted by 10 to 10 alkoxy groups.)

Acrylic resin (2): structural unit derived from the following monomer (b) having the structural unit (a) as a main component
Acrylic resin containing the position (structural unit (b)) of the resin
An acrylic resin having a weight average molecular weight of 1,000,000 to 1,500,000.
(B): carboxyl group, hydroxyl group, amide group, amino group, epoxy group, oxetanyl group,
A monomer containing in the molecule at least one polar functional group selected from the group consisting of an aldehyde group and an isocyanate group and one olefinic double bond

The pressure-sensitive adhesive of the present invention is excellent in flexibility by controlling the amount of low-molecular weight components soluble in tetrahydrofuran (THF) in the pressure-sensitive adhesive, that is, the amount of uncrosslinked components in the pressure-sensitive adhesive. Provides excellent adhesion to the optical laminate. Moreover, when the optical film with an adhesive which laminated | stacked the optical film and this adhesive is laminated | stacked, for example on the glass substrate of a liquid crystal cell, the optical laminated body of this invention will be given. In such an optical laminate, the pressure-sensitive adhesive layer absorbs and relaxes stress caused by dimensional changes of the optical film and the glass substrate under wet heat conditions, so that local stress concentration is reduced and the pressure-sensitive adhesive layer floats on the glass substrate. , Peeling is suppressed. In addition, since optical defects due to non-uniform stress distribution are prevented, white spots are suppressed when the glass substrate is a TN liquid crystal cell (TFT).
Furthermore, even after the film is peeled from the optical laminate for re-attaching the optical film with the pressure-sensitive adhesive, the surface of the glass substrate that has been in contact with the pressure-sensitive adhesive layer hardly generates fogging, adhesive residue, or the like. Excellent reworkability. By this, even if the optical film with adhesive once laminated is peeled off from the glass substrate of the optical laminate, adhesive residue and fogging are suppressed on the surface of the glass substrate after peeling, and it can be used again as a glass substrate. .

Hereinafter, the present invention will be described in detail.
The monomer (a) used for the acrylic resins (1) and (2) of the present invention is a (meth) acrylic acid ester represented by the formula (A).
In the formula, R ₁ represents a hydrogen atom or a methyl group, and R ₂ represents an alkyl group having 1 to 14 carbon atoms or an aralkyl group. The hydrogen atom of the aralkyl group of R ₂ or the hydrogen atom of the alkyl group may be substituted with an alkoxy group having 1 to 10 carbon atoms.

Here, as the monomer (a), for example, methyl acrylate, ethyl acrylate, propyl acrylate, n-butyl acrylate, iso-butyl acrylate, 2-ethylhexyl acrylate, n-octyl acrylate, iso-octyl acrylate, lauryl acrylate Acrylates such as stearyl acrylate, cyclohexyl acrylate, isobornyl acrylate, benzyl acrylate, methoxyethyl acrylate and ethoxymethyl acrylate; methyl methacrylate, ethyl methacrylate, propyl methacrylate, n-butyl methacrylate, iso-butyl methacrylate, 2-ethylhexyl Methacrylate, n-octyl methacrylate, iso-octyl methacrylate, lauryl methacrylate, stearyl methacrylate Acrylate, cyclohexyl methacrylate, isobornyl methacrylate, benzyl methacrylate, can be mentioned methacrylic acid esters such as methoxyethyl methacrylate and ethoxyethyl methacrylate.
Two or more different monomers (a) may be used as the monomer (a).

In the acrylic resin (1) of the present invention, the content of the structural unit (structural unit (a)) derived from the monomer (a) is usually 60 parts by weight with respect to 100 parts by weight of the acrylic resin (1). Above, preferably 70 parts by weight or more.
Moreover, as content of the structural unit (a) in an acrylic resin (2), it is about 70-99.9 weight part normally with respect to 100 weight part of acrylic resins (2), Preferably it is 90-99. About 6 parts by weight.

  The structural unit (structural unit (b)) derived from the monomer (b) is an essential component of the acrylic resin (2), and may be contained as an optional component in the acrylic resin (1). Here, the monomer (b) is composed of at least one polar functional group selected from the group consisting of a carboxyl group, a hydroxyl group, an amide group, an amino group, an epoxy group, an oxetanyl group, an aldehyde group and an isocyanate group, and one olefin. It is a monomer containing an ionic double bond in the molecule.

As specific examples of the monomer (b), examples of the monomer (b) whose polar functional group is a carboxyl group include acrylic acid, methacrylic acid, maleic acid, and itaconic acid. Examples of the monomer (b) that is a hydroxyl group include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, and the like. Examples of the monomer (b) whose polar functional group is an amide group include acrylamide, methacrylamide, N, N-dimethylaminopropylacrylamide, diacetone diamide, N, N-dimethylacrylamide, and N, N-. Examples include diethyl acrylamide and N-methylol acrylamide.
Examples of the monomer (b) whose polar functional group is an epoxy group include glycidyl acrylate, glycidyl methacrylate, 3,4-epoxycyclohexylmethyl acrylate, 3,4-epoxycyclohexylmethyl methacrylate, and the like. Here, a monomer in which an oxygen atom constitutes a 3-membered ring and a 7-membered ring, such as 3,4-epoxycyclohexylmethyl acrylate and 3,4-epoxycyclohexylmethyl methacrylate, is a highly reactive epoxy group. Therefore, it is a monomer (b).
As the monomer (b) whose polar functional group is an oxetanyl group, for example, oxetanyl (meth) acrylate, 3-oxetanylmethyl (meth) acrylate, (3-methyl-3-oxetanyl) methyl (meth) acrylate, (3 -Ethyl-3-oxetanyl) methyl (meth) acrylate and the like. Furthermore, examples of the monomer (b) whose polar functional group is an amino group include N, N-dimethylaminoethyl acrylate and allylamine, and the monomer (b) whose polar functional group is an isocyanate group. Examples of the monomer include 2-methacryloyloxyethyl isocyanate, and examples of the monomer (b) whose polar functional group is an aldehyde group include acrylic aldehyde.

As these monomers (b), two or more different monomers (b) may be used in combination. For example, at least one selected from the group consisting of a hydroxyl group, an amino group and an epoxy group may be used. Simultaneous use of a monomer (b) containing a polar functional group capable of reacting, such as a combination of a monomer (b) containing a polar functional group and a monomer (b) containing an isocyanate group This is not preferable because gelation occurs during polymerization of the acrylic resin.
As the monomer (b), a monomer (b) whose polar functional group is a hydroxyl group and a monomer (b) whose polar functional group is a carboxyl group are preferable, and 4-hydroxybutyl (meta) is particularly preferable. ) Acrylate, acrylic acid and 2-hydroxyethyl (meth) acrylate are preferred.

When the monomer (b) is used for the acrylic resin (1), the content of the structural unit (b) contained in the acrylic resin (1) is usually 0 with respect to 100 parts by weight of the acrylic resin (1). About 1 to 20 parts by weight. When the content of the structural unit (b) is 20 parts by weight or less, it is preferable because the floating peeling between the glass substrate and the adhesive layer tends to be suppressed.
As content of the structural unit (b) contained in an acrylic resin (2), it is about 0.1-30 weight part normally with respect to 100 weight part of acrylic resins, Preferably it is 0.5-10 weight part Degree. When the content of the structural unit (b) is 0.1 parts by weight or more, the cohesive strength of the resulting resin tends to be improved, and when it is 30 parts by weight or less, the dimensions of the optical film change. However, since the pressure-sensitive adhesive layer fluctuates following the dimensional change, there is no difference between the brightness of the peripheral edge of the liquid crystal cell and the brightness of the central part, and white spots and color unevenness tend to be suppressed. To preferred.

In order to make the value of Y, which will be described later, larger than -0.15X + 41, it is only necessary to reduce uncrosslinked components in the pressure-sensitive adhesive, that is, to reduce low molecular weight components dissolved in THF. . Specifically, the structural unit (b) capable of reacting with the crosslinking agent in the acrylic resin (1), which is a low molecular weight component, is increased, or the weight part of the acrylic resin (1) in the crosslinking agent is increased. .
Further, in order to make the value of Y smaller than 0.45X + 24, the uncrosslinked component may be increased in the pressure-sensitive adhesive, that is, the low molecular weight component dissolved in THF may be increased. Specifically, in the acrylic resin (1) which is a low molecular weight component, the structural unit (b) capable of reacting with the crosslinking agent is reduced, or the use part by weight of the acrylic resin (1) in the crosslinking agent is reduced. Good.

  As a weight ratio (nonvolatile content) of the acrylic resins (1) and (2) used in the pressure-sensitive adhesive of the present invention, the acrylic resin (1) is usually 10 to 50 weights with respect to 100 parts by weight of the pressure-sensitive adhesive resin composition. Part, preferably about 20 to 40 parts by weight. When the acrylic resin (1) is 10 parts by weight or more, even if the dimension of the optical film changes, the pressure-sensitive adhesive layer changes following the dimension change. This is preferable because there is no difference in brightness and white spots and color unevenness tend to be suppressed. When the acrylic resin (1) is 50 parts by weight or less, adhesion at high temperature and high humidity is improved. The float and peeling between the glass substrate and the pressure-sensitive adhesive layer tend to decrease, and the reworkability tends to improve, which is preferable.

  When the acrylic resins (1) and (2) used in the present invention are produced, the monomer is different from the monomers (a) and (b), and has one olefinic property in the molecule. You may superpose | polymerize with the monomer (c) containing a double bond and a cyclic structure more than a 5-membered ring. Here, as the monomer (c), for example, a monomer containing one olefinic double bond and an alicyclic structure in the molecule (hereinafter sometimes referred to as an alicyclic monomer); Examples thereof include a monomer containing one olefinic double bond and a heterocyclic structure in the molecule (hereinafter sometimes referred to as a heterocyclic monomer).

The alicyclic structure in the alicyclic monomer is usually a cycloparaffin structure or a cycloolefin structure having 5 or more carbon atoms, preferably about 5 to 7 carbon atoms. The cycloolefin structure contains an olefinic double bond in the alicyclic structure.
Specific monomers that contain one olefinic double bond and alicyclic structure in the molecule include isobornyl acrylate, cyclohexyl acrylate, dicyclopentanyl acrylate, cyclododecyl acrylate, and methylcyclohexyl. Acrylic esters having an alicyclic structure such as acrylate, trimethylcyclohexyl acrylate, tert-butylcyclohexyl acrylate, cyclohexyl α ethoxy acrylate, cyclohexyl phenyl acrylate; isobornyl methacrylate, cyclohexyl methacrylate, dicyclopentanyl methacrylate, methacrylic acid Cyclododecyl, methyl cyclohexyl methacrylate, trimethyl cyclohexyl methacrylate, tert-butyl cyclohexyl methacrylate, cyclohexyl alfa ethoxy Methacrylate, methacrylic acid esters are exemplified having an alicyclic structure such as cyclohexyl phenyl methacrylate.
As the alicyclic monomer, isobornyl acrylate, cyclohexyl acrylate, isobornyl methacrylate, cyclohexyl methacrylate, and dicyclopentanyl acrylate are preferable because they are easily available.
Examples of the acrylate containing a plurality of alicyclic structures include biscyclohexylmethyl itaconate, dicyclooctyl itaconate, dicyclododecylmethyl succinate, and the like. Vinyl cyclohexyl acetate containing a vinyl group is also a monomer ( d).

The heterocyclic structure in the heterocyclic monomer means that at least one methylene group in the alicyclic hydrocarbon group having 5 or more carbon atoms, preferably 5 to 7 carbon atoms is a nitrogen atom, an oxygen atom or a sulfur atom. A heterocyclic group substituted with a heteroatom.
Specific examples include acryloylmorpholine, vinyl caprolactam, N-vinyl-2-pyrrolidone, tetrahydrofurfuryl acrylate, tetrahydrofurfuryl methacrylate, caprolactone-modified tetrahydrofurfuryl acrylate, and the like. Furthermore, an olefinic double bond may be contained in the heterocyclic group such as 2,5-dihydrofuran. Among them, N-vinylpyrrolidone, vinylcaprolactam, and acryloylmorpholine are preferable as the monomer containing one olefinic double bond in the molecule and a heterocyclic structure.

A different monomer (c) may be used as the monomer (c).
The content of the structural unit (structural unit (c)) derived from the monomer (c) contained in the acrylic resin (1) or (2) of the present invention is usually 100 parts by weight of the acrylic resin, It is about 10 parts by weight or less. When the structural unit (c) is contained, even if the dimension of the optical film changes, the pressure-sensitive adhesive layer fluctuates following the change in dimension, so that the brightness between the peripheral edge of the liquid crystal cell and the brightness of the central part is between In some cases, the difference disappears and white spots and color unevenness are suppressed.

  Furthermore, when producing the acrylic resins (1) and (2) used in the present invention, they may be polymerized together with the vinyl monomer (d). The vinyl monomer (d) is a monomer different from the monomers (a) to (c) and has at least one vinyl group in the molecule. For example, vinyl Examples include esters, vinyl halides, vinylidene halides, conjugated diene compounds, styrene monomers, nitrogen-containing aromatic vinyls, and (meth) acrylonitrile.

Examples of the vinyl ester include monovinyl esters such as vinyl acetate, vinyl propionate, vinyl butyrate, vinyl 2-ethylhexanoate and vinyl laurate; and divinyl esters such as divinyl adipate and divinyl sebacate.
Examples of the vinyl halide include vinyl chloride and vinyl bromide, examples of the vinylidene halide include vinylidene chloride, and examples of the (meth) acrylonitrile include acrylonitrile and methacrylonitrile.
The conjugated diene compound is an olefin having a conjugated double bond in the molecule, and specific examples include isoprene, butadiene and chloroprene.
Styrene monomers include styrene, methyl styrene, dimethyl styrene, trimethyl styrene, ethyl styrene, diethyl styrene, triethyl styrene, propyl styrene, butyl styrene, hexyl styrene, heptyl styrene, octyl styrene, fluorostyrene, chlorostyrene, bromo Examples thereof include styrene, dibromostyrene, iodostyrene, nitrostyrene, acetylstyrene, methoxystyrene, and divinylbenzene. Examples of the nitrogen-containing aromatic vinyl include vinyl pyridine and vinyl carbazole.

A plurality of different monomers (d) may be used as the monomer (d).
The structural unit (d) derived from the monomer (d) contained in the acrylic resin (1) or (2) is usually 5 parts by weight or less, preferably 0.05 parts by weight with respect to 100 parts by weight of the acrylic resin. Part or less, and particularly preferably, it is preferably substantially not contained.

  Further, when the acrylic resins (1) and (2) used in the present invention are produced, the monomer is different from the monomers (a) to (d), and has a plurality of olefinic properties in the molecule. The monomer (e) containing a double bond may be contained. Examples of the monomer (e) include (meth) ethylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, 1,3,5-triacryloylhexahydro-S-triazine, tetramethylolmethane tetraacrylate, and the like. ) Acrylates; bis (meth) acrylamides such as methylene bis (meth) acrylamide, ethylene bis (meth) acrylamide, N, N-diallylacrylamide; allyl (meth) acrylate, triallyl isocyanurate, triallylamine, tetraallyl pyromelli Tate, N, N, N ′, N′-tetraallyl-1,4-diaminobutane, tetraallylammonium salt and the like.

A plurality of different monomers (e) may be used as the monomer (e).
The structural unit (e) derived from the monomer (e) contained in the acrylic resin (1) or (2) is usually 5 parts by weight or less, preferably 0.05 parts by weight with respect to 100 parts by weight of the acrylic resin. Part or less, and particularly preferably, it is preferably substantially not contained.

Examples of the method for producing the acrylic resin (1) used in the present invention include a solution polymerization method, an emulsion polymerization method, a bulk polymerization method, and a suspension polymerization method.
In the production of the acrylic resin (1), a polymerization initiator is usually used. The polymerization initiator is used in an amount of about 0.1 to 5 parts by weight with respect to a total of 100 parts by weight of all monomers used for the production of the acrylic resin (1).

  Examples of the polymerization initiator include a thermal polymerization initiator and a photopolymerization initiator. Examples of the photopolymerization initiator include 4- (2-hydroxyethoxy) phenyl (2-hydroxy-2-propyl) ketone. Can be mentioned. Examples of the thermal polymerization initiator include 2,2′-azobisisobutyronitrile, 2,2′-azobis (2-methylbutyronitrile), 1,1′-azobis (cyclohexane-1-carbonitrile). 2,2′-azobis (2,4-dimethylvaleronitrile), 2,2′-azobis (2,4-dimethyl-4-methoxyvaleronitrile), dimethyl-2,2′-azobis (2-methylpro) Azo compounds such as pionate) and 2,2′-azobis (2-hydroxymethylpropionitrile); lauryl peroxide, tert-butyl hydroperoxide, benzoyl peroxide, tert-butyl peroxybenzoate, cumene hydroper Oxide, diisopropyl peroxydicarbonate, di-n-propyl peroxydicarbonate, te organic peroxides such as t-butylperoxyneodecanoate, tert-butylperoxypivalate, (3,5,5-trimethylhexanoyl) peroxide; inorganic peroxides such as potassium persulfate, ammonium persulfate and hydrogen peroxide An oxide etc. are mentioned. A redox initiator using a thermal polymerization initiator and a reducing agent in combination can also be used as the polymerization initiator.

As the method for producing the acrylic resin (1), the solution polymerization method is particularly preferable. As a specific example of the solution polymerization method, a desired monomer and an organic solvent are mixed to prepare a mixed solution having a monomer concentration of 20% by weight or more, preferably 30 to 60% by weight, and then in a nitrogen atmosphere. And a method of adding a polymerization initiator and stirring at about 40 to 90 ° C., preferably about 60 to 80 ° C. for about 3 to 10 hours. In order to control the reaction, the monomer or polymerization initiator to be used may be added during the polymerization or after being dissolved in an organic solvent.
Examples of the organic solvent include aromatic hydrocarbons such as toluene and xylene; esters such as ethyl acetate and butyl acetate; aliphatic alcohols such as n-propyl alcohol and isopropyl alcohol; methyl ethyl ketone and methyl isobutyl ketone. And ketones.

  As the molecular weight of the acrylic resin (1) thus obtained, the weight average molecular weight in terms of standard polystyrene of gel permeation chromatography (GPC) is usually from 50,000 to 250,000. When the weight average molecular weight is 50,000 or more, the adhesiveness under high temperature and high humidity is improved, and the floating and peeling between the glass substrate and the pressure-sensitive adhesive layer tend to decrease, and the reworkability tends to improve. Preferably, the weight average molecular weight is 250,000 or less, even if the optical film dimensions change, the pressure-sensitive adhesive layer fluctuates following the dimensional change, so the brightness and center of the periphery of the liquid crystal cell This is preferable because there is no difference between the brightness and the brightness of the part, and white spots and color unevenness tend to be suppressed.

As a manufacturing method of the acrylic resin (2) used for this invention, a solution polymerization method, an emulsion polymerization method, a block polymerization method, a suspension polymerization method etc. are mentioned, for example, Among these, a solution polymerization method is preferable.
As a specific example of the solution polymerization method, a desired monomer and an organic solvent are mixed to prepare a mixed solution having a monomer concentration of 40% by weight or more, preferably 50 to 60% by weight, and then in a nitrogen atmosphere. In this method, about 0.001 to 0.2 parts by weight of a polymerization initiator is added and stirred at about 40 to 90 ° C., preferably about 50 to 70 ° C. for 8 hours or more, preferably about 10 to 12 hours. Etc.
As the polymerization initiator used in the acrylic resin (2), the same polymerization initiator as that used in the acrylic resin (1) is used. Moreover, as an organic solvent, the organic solvent similar to what was used by acrylic resin (1) is used.

  As the molecular weight of the acrylic resin (2) thus obtained, the weight average molecular weight (Mw) in terms of standard polystyrene of gel permeation chromatography (GPC) is 1,000,000 to 1,500,000. When the weight average molecular weight is 1,000,000 or more, the adhesiveness under high temperature and high humidity is improved, and there is a tendency that the floating and peeling between the glass substrate and the pressure-sensitive adhesive layer are reduced, and the reworkability is improved. Therefore, it is preferable. If the weight average molecular weight is 1,500,000 or less, even if the dimensions of the optical film change, the pressure-sensitive adhesive layer fluctuates following the dimensional change, so the brightness between the periphery of the liquid crystal cell and the brightness of the center This is preferable because there is no difference between the two and there is a tendency to suppress white spots and color unevenness.

The cross-linking agent used in the pressure-sensitive adhesive of the present invention has at least two functional groups capable of cross-linking with the polar functional group contained in the acrylic resin (2). Specifically, it is an isocyanate compound or an epoxy. Examples of such compounds include metal compounds, metal chelate compounds, and aziridine compounds.
Here, the isocyanate compound includes, for example, tolylene diisocyanate, hexamethylene diisocyanate, isophorone diisocyanate, xylylene diisocyanate, hydrogenated xylylene diisocyanate, diphenylmethane diisocyanate, hydrogenated diphenylmethane diisocyanate, tetramethylxylylene diisocyanate, naphthalene diisocyanate, Examples thereof include phenylmethane triisocyanate and polymethylene polyphenyl isocyanate. Further, adducts obtained by reacting the isocyanate compound with polyols such as glycerol and trimethylolpropane, and those obtained by making the isocyanate compound into a 2, trimer or the like are also the crosslinking agent of the present invention. Of these, an adduct of tolylene diisocyanate is particularly preferable.

  Examples of the epoxy compound include bisphenol A type epoxy resin, ethylene glycol glycidyl ether, polyethylene glycol diglycidyl ether, glycerin diglycidyl ether, glycerin triglycidyl ether, 1,6-hexanediol diglycidyl ether, trimethylol propane tri Examples include glycidyl ether, diglycidyl aniline, N, N, N ′, N′-tetraglycidyl-m-xylenediamine, and 1,3-bis (N, N′-diglycidylaminomethyl) cyclohexane.

  Examples of the metal chelate compound include compounds in which acetylacetone or ethyl acetoacetate is coordinated to a polyvalent metal such as aluminum, iron, copper, zinc, tin, titanium, nickel, antimony, magnesium, vanadium, chromium and zirconium. Can be mentioned.

  Examples of aziridine compounds include N, N′-diphenylmethane-4,4′-bis (1-aziridinecarboxide), N, N′-toluene-2,4-bis (1-aziridinecarboxamide), triethylene Melamine, bisisophthaloyl-1- (2-methylaziridine), tri-1-aziridinylphosphine oxide, N, N'-hexamethylene-1,6-bis (1-aziridinecarboxide), trimethylolpropane -Tri-β-aziridinylpropionate and tetramethylolmethane-tri-β-aziridinylpropionate.

  Two or more types of crosslinking agents may be used as the crosslinking agent. As the usage-amount of the crosslinking agent (nonvolatile content) in an adhesive, it is about 0.8-5 weight part normally with respect to a total of 100 weight part (nonvolatile content) of acrylic resin (1) and (2), Preferably About 1 to 3 parts by weight. Specifically, Patent Document 1 uses 0.1 parts by weight and 0.15 parts by weight of a crosslinking agent with respect to a total of 100 parts by weight (nonvolatile content) of the acrylic resins (1) and (2). However, when the amount of the crosslinking agent is 0.8 parts by weight or more, the uncrosslinked component in the pressure-sensitive adhesive is decreased, and the value of Y described later tends to be larger than −0.15X + 41. This is preferable because durability such as float-off between the substrate and the pressure-sensitive adhesive layer becomes good. On the other hand, if it is 5 parts by weight or less, the uncrosslinked component in the pressure-sensitive adhesive increases, and the value of Y described later tends to be smaller than 0.45X + 24. Since the followability of the agent layer is excellent, white spots and color unevenness tend to decrease, which is preferable.

  Especially, since the polar functional group contained in the acrylic resin (1) is a hydroxyl group and the crosslinking agent is an isocyanate compound, the hydroxyl group and the crosslinking agent are excellent in reactivity. By simply controlling the amount of hydroxyl group and the amount of crosslinking agent, the value of Y described later can be easily controlled. In particular, a group consisting of tolylene diisocyanate, an adduct obtained by reacting tolylene diisocyanate with a polyol such as glycerol or trimethylolpropane, a dimerized tolylene diisocyanate, and a trimerized tolylene diisocyanate At least one crosslinking agent selected from is preferred.

The pressure-sensitive adhesive of the present invention is a pressure-sensitive adhesive obtained by crosslinking the acrylic resins (1) and (2) thus obtained with a cross-linking agent. The weight percentage Y (%) of the high molecular weight component in the tetrahydrofuran-insoluble portion of the pressure-sensitive adhesive represented by () satisfies the formulas (I) and (II).
40 ≦ X ≦ 70 (I)
-0.51X + 41 <Y <0.45X + 24 (II)
Y = B- (100-X) * C / 100 (III)

In the formula, X represents a weight percentage (%) of the tetrahydrofuran-insoluble matter relative to the pressure-sensitive adhesive. Specifically, the measurement is performed by the following method.
(I) An adhesive layer (thickness 25 μm) having an area of about 8 cm × about 8 cm and a metal mesh of SUS304 mesh (about 10 cm × about 10 cm, weight (Wm)) are bonded.
(Ii) Weigh the weight (Ws) of the bonded product obtained in (i), and wrap the adhesive layer 4
After folding and fastening with staples, weigh (Wb).
(Iii) Put the mesh obtained in (ii) in a 125 ml glass container and add THF 10
After adding ml and soaking, the glass container is stored at room temperature for 6 days.
(Iv) The mesh is taken out from the glass container, dried at 120 ° C. for 24 hours, weighed (Wa), and the gel fraction is calculated based on the following formula.
X (% by weight) = [{Wa− (Wb−Ws) −Wm} / (Ws−Wm)] × 100

  When X is 70% or less, the crosslinking density is low, the flexibility is excellent, and white spots and uneven color phenomenon tend to be suppressed, and when X is 40% or more, the cohesive force is improved. , Because durability tends to improve.

B in the formula (III) represents a weight percentage of a high molecular weight component having a molecular weight of 300,000 or more in the mixture of the acrylic resins (1) and (2), and C is a high molecular weight having a molecular weight of 300,000 or more in the THF-soluble component of the adhesive. Represents the weight percentage of the component. That is, Y defined by the formula (III) represents the THF insoluble content in the pressure-sensitive adhesive, that is, the weight percentage of the high molecular weight component having a weight average molecular weight of 300,000 or more of the component crosslinked by the crosslinking agent.
In addition, the said molecular weight and the weight percentage are measured by standard polystyrene conversion of a gel permeation chromatography (GPC).
When Y is less than 0.45X + 24, the crosslinking density is low, the flexibility is excellent, and white spots and color unevenness tend to be suppressed, which is preferable. When Y is −0.51X + 41 or more, the cohesive force is improved and the durability tends to be improved.

The pressure-sensitive adhesive of the present invention preferably contains a silane compound in order to improve the adhesion between the pressure-sensitive adhesive layer and the glass substrate. The silane compound may be either a monomer or an oligomer. Examples of the silane compound monomer include vinyltrimethoxysilane, vinyltriethoxysilane, vinyltris (2-methoxyethoxy) silane, N- (2-aminoethyl) -3-aminopropylmethyldimethoxysilane, N- ( 2-aminoethyl) -3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, 2- (3,4-epoxy (Cyclohexyl) ethyltrimethoxysilane, 3-chloropropylmethyldimethoxysilane, 3-chloropropyltrimethoxysilane, 3-methacryloxypropyltrimethoxysilane, 3-mercaptopropyltrimethoxysilane, 3-glycidoxypropyltrimethoxysilane Down, 3-glycidoxypropyl triethoxysilane, 3-glycidoxypropyl dimethoxymethyl silane, 3-glycidoxypropyl ethoxy dimethyl silane, and the like. Examples of the silane compound oligomer include 3-mercaptopropyltrimethoxysilane-tetramethoxysilane copolymer, 3-mercaptopropyltrimethoxysilane-tetraethoxysilane copolymer, mercaptomethyltrimethoxysilane-tetramethoxysilane copolymer, mercaptomethyltrimethoxysilane- Tetraethoxysilane copolymer, mercaptomethyltriethoxysilane-tetramethoxysilane copolymer, mercaptomethyltriethoxysilane-tetraethoxysilane copolymer, 3-methacryloxypropyltrimethoxysilane-tetramethoxysilane copolymer, 3-acryloxypropyltrimethoxysilane- Tetramethoxysilane copolymer, vinyltrimethoxysilane-tetramethoxysilane copolymer, -Aminopropyltrimethoxysilane-tetramethoxysilane copolymer, 3-glycidoxypropyltrimethoxysilane-tetraethoxysilane copolymer, 3-glycidoxypropylmethyldiethoxysilane-tetramethoxysilane copolymer, 3-glycidoxypropyltri Examples thereof include ethoxysilane-tetramethoxysilane copolymer, 2- (3,4 epoxycyclohexyl) ethyltrimethoxysilane-tetraethoxysilane copolymer, and tetraethoxysilane copolymer.
Two or more types of silane compounds may be used in the pressure-sensitive adhesive of the present invention.

  The amount (solution) of the silane compound used in the pressure-sensitive adhesive is usually about 0.0001 to 10 parts by weight, preferably 0.01 to 100 parts by weight (nonvolatile content) of the acrylic resin tail composition. Used in an amount of 5 parts by weight. It is preferable that the amount of the silane compound is 0.0001 part by weight or more, because the adhesiveness between the pressure-sensitive adhesive layer and the glass substrate is improved. Moreover, since it exists in the tendency which suppresses that a silane type compound bleeds out from an adhesive layer as the quantity of a silane type compound is 10 weight part or less, it is preferable.

The pressure-sensitive adhesive of the present invention contains the acrylic resin (1), the acrylic resin (2) and a crosslinking agent as described above, and preferably contains a silane compound, and further contains a crosslinking catalyst, a weathering stabilizer, and a tackifier. Plasticizers, softeners, dyes, pigments, inorganic fillers, and the like may be blended.
Among them, when a crosslinking catalyst and a crosslinking agent are blended in the pressure-sensitive adhesive, an optical film with a pressure-sensitive adhesive can be prepared by aging in a short time, and the optical laminate including the film is between the optical film and the pressure-sensitive adhesive layer. In some cases, floating, peeling and foaming in the pressure-sensitive adhesive layer are suppressed, and the reworkability is excellent.
Examples of the crosslinking catalyst include amine compounds such as hexamethylenediamine, ethylenediamine, polyethyleneimine, hexamethylenetetramine, diethylenetriamine, triethylenetetramine, isophoronediamine, triethylenediamine, polyamino resin, and melamine resin. When an amine compound is used as a crosslinking catalyst for the pressure-sensitive adhesive, an isocyanate compound is suitable as the crosslinking agent.

The optical film with pressure-sensitive adhesive of the present invention is composed of the above-mentioned pressure-sensitive adhesive and optical film. As a method for producing the same, for example, a pressure-sensitive adhesive diluted with an organic solvent is applied onto a release film, and 60 The organic solvent is distilled off by heating at ~ 120 ° C for about 0.5 to 10 minutes to obtain an adhesive layer. Next, after pasting the optical film on the pressure-sensitive adhesive layer, in an atmosphere of 23 ° C. and 65% humidity, the film is aged for about 5 to 20 days, and after the crosslinking agent has reacted sufficiently, the release film is peeled off. Method for obtaining an optical film with an adhesive; after obtaining an adhesive layer in the same manner as described above, the release film and the adhesive layer are alternately laminated on the obtained laminate of the release film and the adhesive layer. After being combined in multiple layers, if the atmosphere is at 23 ° C. and humidity 65%, it is aged for 5 to 20 days, and after the crosslinking agent has reacted sufficiently, the release film is peeled off, and an optical film is pasted instead. And a method of further peeling the release film to obtain an optical film with an adhesive.
Here, a peeling film is a base material at the time of forming an adhesive layer. In some cases, it is a base material that protects the pressure-sensitive adhesive layer from foreign matters such as dust and dust during aging and storage as an optical film with pressure-sensitive adhesive. As a specific example of the release film, a film made of various resins such as polyethylene terephthalate, polybutylene terephthalate, polycarbonate, and polyacrylate is used as a base material, and a release treatment (silicone treatment) is performed on a bonding surface with the adhesive layer of the base material. Etc.).

  The optical film used for the optical film with pressure-sensitive adhesive of the present invention is a film having optical properties, and examples thereof include a polarizing film and a retardation film. A polarizing film is an optical film having a function of emitting polarized light with respect to incident light such as natural light. As a polarizing film, a linearly polarizing film having a property of absorbing linearly polarized light having a vibrating surface parallel to the optical axis and transmitting linearly polarized light having a vibrating surface that is a vertical surface, parallel to the optical axis. Examples thereof include a polarizing separation film that reflects linearly polarized light on the vibration surface, and an elliptically polarizing film in which a polarizing film and a retardation film described later are laminated. Specific examples of the polarizing film include a film in which a dichroic dye such as iodine or a dichroic dye is adsorbed and oriented on a uniaxially stretched polyvinyl alcohol film.

  The retardation film is an optical film having optical anisotropy such as uniaxial or biaxial, for example, polyvinyl alcohol, polycarbonate, polyester, polyarylate, polyimide, polyolefin, polystyrene, polysulfone, polyethersulfone, polysulfone, By stretching a polymer film made of vinylidene fluoride / polymethyl methacrylate, liquid crystal polyester, acetyl cellulose, cyclic polyolefin, saponified ethylene-vinyl acetate copolymer, polyvinyl chloride, etc. to about 1.01 to 6 times. The stretched film etc. which are obtained are mentioned. Among these, a polymer film obtained by uniaxially or biaxially stretching polycarbonate or polyvinyl alcohol is preferable.

  As the retardation film, uniaxial retardation film, wide viewing angle retardation film, low photoelasticity retardation film, temperature compensation retardation film, LC film (rod-like liquid crystal twist orientation), WV film (disc-like liquid crystal tilt) Orientation), NH film (rod-like liquid crystal tilted orientation), VAC film (fully biaxially oriented retardation film), newVAC film (biaxially oriented retardation film), and the like.

  Furthermore, what further bonded the board | substrate film (Protective Film) to the single side | surface or both surfaces of these optical films is used suitably as an optical film. Examples of the substrate film include an acrylic resin film different from the acrylic resin of the present invention, an acetyl cellulose film such as a cellulose triacetate film, a polyester resin film, an olefin resin film, a polycarbonate resin film, a polyether ether ketone resin film, and a polysulfone. Resin film etc. are mentioned. The substrate film may contain an ultraviolet absorber such as a salicylic acid ester compound, a benzophenone compound, a benzotriazole compound, a triazine compound, a cyanoacrylate compound, or a nickel complex compound. Among the substrate films, acetylcellulose-based films are preferable.

  The optical laminate of the present invention comprises an optical film with an adhesive and a glass substrate. The optical laminate can usually be produced by bonding the pressure-sensitive adhesive layer of the optical film with pressure-sensitive adhesive and the glass substrate. Here, as a glass substrate, the glass substrate of a liquid crystal cell, the glass for glare-proof, the glass for sunglasses etc. are mentioned, for example. Among them, an adhesive layer of an optical film with an adhesive (upper polarizing plate) is bonded to the glass substrate at the upper part of the liquid crystal cell, and another optical film with adhesive (lower polarizing plate) on the glass substrate at the lower part of the liquid crystal cell. ) Is preferably used because it can be used as a liquid crystal display device. Examples of the material for the glass substrate include soda lime glass, low alkali glass, and non-alkali glass.

  The optical layered body of the present invention is peeled off from the surface of the glass substrate that has been in contact with the pressure-sensitive adhesive layer even after the optical film with the pressure-sensitive adhesive is peeled off from the optical layered body. It is possible to easily re-adhere the optical film with the adhesive to the glass substrate, that is, it has excellent reworkability.

Hereinafter, the present invention will be described more specifically with reference to examples. In the examples, “parts” and “%” are based on weight unless otherwise specified. The nonvolatile content was measured by a measuring method according to JIS K-5407. Specifically, the weight of the residual non-volatile content after taking an arbitrary weight of the pressure-sensitive adhesive solution in a petri dish and drying it in an explosion-proof oven at 115 ° C. for 2 hours, expressed as a percentage of the weight of the solution first measured. is there. The weight average molecular weight measured from standard polystyrene using a device, sample concentration 5 mg / ml, the sample introduction amount 100Myuml, column as manufactured by Tosoh Corporation: two TSKgel G6000H _XL, two TSKgel G5000H _XL sequentially, those series Was obtained using tetrahydrofuran as an eluent under the conditions of a temperature of 40 ° C. and a flow rate of 1 ml / min.

<Examples of acrylic resin production>
(Polymerization example 1)
A reactor equipped with a cooling pipe, a nitrogen introduction pipe, a thermometer, and a stirrer was charged with 222 parts of ethyl acetate, the air inside the apparatus was replaced with nitrogen gas, and oxygen-free, then the internal temperature was raised to 75 ° C. Warm up. After adding a total amount of a solution in which 0.5 part of azobisisobutyronitrile (hereinafter referred to as AIBN) was dissolved in 12.5 parts of ethyl acetate, the internal temperature was maintained at 74 to 76 ° C., while the monomer (a) was used. A mixed solution of 36 parts of butyl acrylate, 44 parts of butyl methacrylate and 20 parts of methyl acrylate was dropped into the reaction system over 3 hours. Thereafter, the temperature was kept at 74 to 76 ° C. for 5 hours to complete the reaction. The weight average molecular weight of GPC in terms of polystyrene was 100,000.

(Polymerization Examples 2 to 5)
With the monomer composition shown in Table 1, the reaction was completed in substantially the same manner as in Polymerization Example 1.

(Polymerization Example 6)
In a reactor equipped with a cooling tube, a nitrogen introduction tube, a thermometer, and a stirrer, 81.8 parts of acetone, 98.9 parts of butyl acrylate (hereinafter referred to as BA) as monomer (a), monomer (b) A mixture solution of 1.1 parts of acrylic acid (hereinafter referred to as AA) was charged, the air in the apparatus was replaced with nitrogen gas, and the internal temperature was raised to 55 ° C. without containing oxygen. A total amount of a solution prepared by dissolving 0.14 part of rhonitrile (hereinafter referred to as AIBN) in 10 parts of acetone was added. One hour after addition of the initiator, the acetone solvent was continuously added at an addition rate of 17.3 parts by weight / hr so that the concentration of the acrylic resin excluding the monomer (hereinafter sometimes referred to as reaction concentration) was 35% by weight. While being added to the reactor, the temperature was kept at 54 to 56 ° C. for 12 hours, and finally an ethyl acetate solvent was added to adjust the reaction concentration to 20%. The weight average molecular weight was 1,200,000 and Mw / Mn was 3.9.

(Polymerization Examples 7-8)
The reaction was completed in the same manner as in Polymerization Example 6 with the monomer composition shown in Table 2.

  Table 2 summarizes the monomer composition ratios, molecular weights, and molecular weight distributions of Polymerization Examples 6 to 8.

Example 1
<Examples of adhesive production>
Acrylic resins (1) and (2) were mixed at a weight ratio shown in Table 3 to obtain an ethyl acetate solution of the acrylic resin composition. To 100 parts of the nonvolatile content of the resulting solution, 2 parts (nonvolatile content) of a tolylene diisocyanate adduct (trade name: Coronate L, manufactured by Nippon Polyurethane Industry Co., Ltd.) and a silane compound (trade name: Y11597, Toray Industries, Inc.) 0.1 parts of Dow Corning) was mixed to obtain the pressure-sensitive adhesive of the present invention.

<Example of production of optical film with adhesive and optical laminate>
The pressure-sensitive adhesive thus obtained was dried on the release-treated surface of a polyethylene terephthalate film (product name: PET3811, manufactured by Lintec Co., Ltd.) that was release-treated using an applicator so that the thickness after drying was 25 μm. It was applied and dried at 90 ° C. for 1 minute to obtain a sheet-like pressure-sensitive adhesive. Next, a polarizing film (a film having a three-layer structure sandwiched between triacetyl cellulose-based protective films on both sides of a stretched film obtained by adsorbing iodine to polyvinyl alcohol) as an optical film is obtained as described above. The surfaces having the pressure-sensitive adhesive were pasted with a laminator, and then aged for 10 days under the conditions of a temperature of 23 ° C. and a humidity of 65% to obtain an optical film with a pressure-sensitive adhesive provided with a pressure-sensitive adhesive layer. Subsequently, the optical film with pressure-sensitive adhesive was stuck to both surfaces of a glass substrate for liquid crystal cells (Corning Co., Ltd., 1737) so as to be crossed Nicol, thereby obtaining an optical laminate. When stored at 80 ° C. and Dry for 96 hours (heat resistance), and when stored at 60 ° C. and 90% RH for 96 hours (moisture and heat resistance), after heating to 60 ° C., the temperature is decreased to −20 ° C., and further to 60 ° C. The process of raising the temperature to 1 cycle (1 hour) and when stored for 100 cycles (heat shock resistance, HS in Table 4), durability in the optical laminate after storage, and heat resistance conditions The appearance of white spots was visually observed. The results are classified as follows and shown in Table 4.

<White Leakage of Optical Laminate>
The evaluation of the expression state of white spots was performed in the following four stages.
A: No white spots are observed.
○: White spots are hardly noticeable.
Δ: White spots are slightly noticeable.
X: White spots are noticeable.

<Durability of optical laminate>
The durability was evaluated in the following four stages.
A: No change in appearance such as floating, peeling or foaming is observed.
○: Almost no change in appearance such as floating, peeling or foaming.
Δ: Appearance changes such as floating, peeling and foaming are slightly noticeable.
X: Appearance changes such as floating, peeling and foaming are noticeable.

<Reworkability>
First, the optical laminate was prepared as a 25 mm × 150 mm test piece. Next, this test piece was pasted on a glass substrate for liquid crystal cells (Soda Lime Glass, manufactured by Nippon Sheet Glass Co., Ltd.) using a pasting device (“Lami Packer” manufactured by Fuji Plastic Machinery Co., Ltd.), and 50 ° C., 5 kg / cm. ² (490.3 kPa) was autoclaved for 20 minutes. Subsequently, after heat treatment at 50 ° C. for 2 hours, the sample was stored in an oven at 50 ° C. for 48 hours, and then the adhesion test piece was put at a speed of 300 mm / min in an atmosphere of 23 ° C. and relative humidity 65% RH. As a result of observing the state of the glass plate surface, it was good.

(Examples 2-16 Comparative Examples 1-8)
Acrylic resins (1) and (2) were mixed according to Example 1 at a weight ratio shown in Table 3 to obtain an ethyl acetate solution of the acrylic resin composition. A crosslinking agent and a silane compound were mixed with 100 parts of the nonvolatile content of the obtained solution to obtain the pressure-sensitive adhesive of the present invention.

  Table 3 shows the mixing ratio of acrylic resins (1) and (2), the type and amount of crosslinking agent, the type and amount of silane compound, and the weight percentage B of components having a molecular weight of 300,000 or more in the mixture of acrylic resins (1) and (2). Summarized.

Abbreviations for the crosslinking agent and silane compound in Table 3 are shown below.
Coronate L: Tolylene diisocyanate adduct manufactured by Nippon Polyurethane Industry Co., Ltd.
Body "Coronate L"
D-140N: Mitsui Takeda Chemical Co., Ltd. isophorone diisocyanate adduct body
"Takenate D-140N"
FL-2: Tolylene diisocyanate isocyania manufactured by Sumika Bayer Urethane Co., Ltd.
Nurate "Sumijour FL-2"
Y11597: Silane agent “Y11597” manufactured by Toray Dow Corning Co., Ltd.
X-41-1805: Shin-Etsu Chemical silicone alkoxy oligomer
"X-41-1805"

Table 4 shows the weight percentage (%) X of the tetrahydrofuran-insoluble matter relative to the pressure-sensitive adhesive, the weight percentage (%) C, Y (= B- (100-X) × C / of the component having a molecular weight of 300,000 or more in the tetrahydrofuran-soluble content of the pressure-sensitive adhesive. 100), and white spots, heat resistance, moisture resistance, and HS durability results.
The results in Table 4 are summarized in FIG. Examples (○) and comparative examples (▲) are shown.
Reworkability was good.

  The pressure-sensitive adhesive of the present invention can be used as a pressure-sensitive adhesive suitable for an optical laminate such as a TN liquid crystal cell (TFT). Moreover, when the composition of this invention is used for the adhesive of a STN liquid crystal cell, the color nonuniformity of the optical laminated body obtained can be suppressed.

The correlation between X and Y in Table 4 is shown. Examples (◯) and comparative examples (例 を) are represented by a straight line that descends to the right representing Y = −0.15X + 41, and a straight line that proceeds to the right represents Y = 0.45X + 24.

Claims (14)

In the pressure-sensitive adhesive obtained by cross-linking acrylic resins (1) and (2) with a cross-linking agent, the weight percentage X (%) of the tetrahydrofuran-insoluble content with respect to the pressure-sensitive adhesive and the tetrahydrofuran-insoluble content of the pressure-sensitive adhesive represented by the formula (III) A pressure-sensitive adhesive characterized in that the weight percentage Y (%) of the high molecular weight component in the formula satisfies the formulas (I) and (II).
40 ≦ X ≦ 70 (I)
-0.51X + 41 <Y <0.45X + 24 (II)
Y = B- (100-X) * C / 100 (III)
(In the formula, X represents the weight percentage (%) of the tetrahydrofuran insoluble to the adhesive, B represents the weight percentage of the component having a molecular weight of 300,000 or more in the mixture of the acrylic resins (1) and (2), and C is (Represents the weight percentage of components with a molecular weight of 300,000 or more in the tetrahydrofuran dissolved content of the adhesive.)
Acrylic resin (1): Main component is a structural unit (structural unit (a)) derived from the following monomer (a)
An acrylic resin having a weight average molecular weight of 50,000 to 250,000.
(A): (Meth) acrylic acid ester represented by formula (A)

(In the formula, R ₁ represents a hydrogen atom or a methyl group, R ₂ represents an alkyl group or an aralkyl group having 1 to 14 carbon atoms. The hydrogen atom of the alkyl group or the aralkyl group of R ₂ has 1 carbon atom. Optionally substituted by 10 to 10 alkoxy groups.)
Acrylic resin (2): structural unit derived from the following monomer (b) having the structural unit (a) as a main component
Acrylic resin containing the position (structural unit (b)) of the resin
An acrylic resin having a weight average molecular weight of 1,000,000 to 1,500,000.
(B): carboxyl group, hydroxyl group, amide group, amino group, epoxy group, oxetanyl group,
A monomer containing in the molecule at least one polar functional group selected from the group consisting of an aldehyde group and an isocyanate group and one olefinic double bond   The pressure-sensitive adhesive according to claim 1, further comprising a structural unit (b) in the acrylic resin (1).   The structural unit (b) contained in the acrylic resin (1) is a monomer containing in the molecule thereof at least one hydroxyl group and one olefinic double bond. The adhesive as described in.   The pressure-sensitive adhesive according to claim 1, wherein the crosslinking agent is an isocyanate-based crosslinking agent.   The cross-linking agent is at least one selected from the group consisting of tolylene diisocyanate, an adduct obtained by reacting tolylene diisocyanate with a polyol, one obtained by dimerizing tolylene diisocyanate, and one obtained by trimerizing tolylene diisocyanate. It is a seed | species crosslinking agent, The adhesive in any one of Claims 1-4 characterized by the above-mentioned.   Furthermore, a silane compound is contained, The adhesive in any one of Claims 1-5 characterized by the above-mentioned.   The optical film with an adhesive formed by laminating | stacking the adhesive in any one of Claims 1-6 on both surfaces or one side of an optical film.   The optical film with pressure-sensitive adhesive according to claim 7, wherein the optical film is a polarizing film and / or a retardation film.   The optical film with an adhesive according to claim 7 or 8, wherein the optical film is an optical film obtained by further bonding an acetylcellulose-based film as a protective film.   The optical film with an adhesive according to any one of claims 7 to 9, wherein a release film is further laminated on the adhesive layer of the optical film with an adhesive.   The optical laminated body formed by laminating | stacking a glass base material on the adhesive layer of the optical film with an adhesive in any one of Claims 7-10.   The optical laminated body formed by laminating | stacking a glass base material on the adhesive layer obtained by peeling after peeling a peeling film from the optical film with an adhesive of Claim 11.   The optical laminated body formed by again laminating | stacking an optical film with an adhesive on the glass substrate obtained by peeling after peeling an optical film with an adhesive from the optical laminated body of Claim 11 or 12.   Satisfying formulas (I) and (II), characterized in that 0.8 to 5 parts by weight of a crosslinking agent is mixed with 100 parts by weight (non-volatile content) of acrylic resins (1) and (2). A method for producing an adhesive.

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