JP2015004072A - Adhesive composition and optical member using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an adhesive composition which can form an adhesive layer excellent in light leakage resistance and durability.SOLUTION: An adhesive composition contains: 100 pts.mass of a (meth)acrylic copolymer having a weight average molecular weight of 1,000,000-2,000,000 which comprises 0-9 pts.mass of a carboxyl group-containing monomer, 0-1.8 pts.mass of a hydroxy group-containing (meth)acrylic monomer, and 99.9-89.2 pts.mass of a (meth)acrylic acid ester monomer (where the total amount of the carboxyl group-containing monomer and the hydroxy group-containing (meth)acrylic monomer is not 0 pt.mass); and 0.05-5 pts.mass of a carbodiimide crosslinking agent. An optical member uses the adhesive composition.

Description

  The present invention relates to an adhesive composition and an optical member using the same. More specifically, the present invention relates to a pressure-sensitive adhesive composition excellent in heat resistance and flexibility and an optical member using the same.

  Recently, the use of flat panel displays (FPD) such as liquid crystal display devices (LCD), plasma displays (PDP), and organic EL devices has been expanded. In connection with this, the improvement of durability of the adhesive used for FPD is calculated | required. In addition, when an adhesive is used in an LCD, characteristics that prevent light leakage due to contraction of the polarizing plate have been demanded.

  Patent Document 1 discloses a pressure-sensitive adhesive containing a copolymer composition of an ethylenically unsaturated monomer capable of reacting with an isocyanate group and an carbodiimide compound containing an isocyanate group, the main component being an alkyl acrylate monomer. A composition is disclosed. According to Patent Document 1, the ethylenically unsaturated monomer capable of reacting with the isocyanate group is based on the copolymer composition (ii) (meth) acrylic acid hydroxyalkyl ester monomer 2-6. It is described that it consists of 0.5 to 1% by weight of (%) carboxyl group-containing monomer. The pressure-sensitive adhesive composition of Patent Document 1 has a high crosslinking speed and high cohesive strength and strong adhesive strength. Therefore, it is suitable for sticking to inorganic materials such as glass, ceramics, and tiles, and the cohesive strength rises quickly. There are advantages such as excellent adhesive strength, water resistance and moisture resistance in a normal state, heat resistance which does not cause blistering or floating at high temperature, and no adhesive residue when peeled off from the adherend.

Japanese Patent No. 4067173

  However, when the pressure-sensitive adhesive layer formed from the pressure-sensitive adhesive composition described in Patent Document 1 is used particularly for a polarizing plate, problems such as poor light leakage resistance and durability, such as occurrence of problems such as peeling over time, occur. was there.

  This invention is made | formed in view of the said situation, and it aims at providing the adhesive composition which can form the adhesion layer excellent in light leakage resistance and durability.

  The present inventors have intensively studied to solve the above problems. As a result, it was found that a pressure-sensitive adhesive composition containing a (meth) acrylic copolymer having a specific composition and a carbodiimide-based crosslinking agent exhibits excellent light leakage resistance and durability. It came to be completed.

  That is, the present invention includes 0 to 9 parts by mass of a carboxyl group-containing monomer, 0 to 1.8 parts by mass of a hydroxy group-containing (meth) acrylic monomer, and 99.9 to 89.2 parts by mass of (meth) acrylic acid. It consists of ester monomers (however, the total amount of the carboxyl group-containing monomer and the hydroxy group-containing (meth) acrylic monomer is not 0 parts by mass) and has a weight average molecular weight of 1,000,000 to 2,000,000. A pressure-sensitive adhesive composition containing 100 parts by mass of a polymer; and 0.05 to 5 parts by mass of a carbodiimide-based crosslinking agent.

  The pressure-sensitive adhesive composition of the present invention has excellent flexibility and durability. Therefore, the pressure-sensitive adhesive layer formed from the pressure-sensitive adhesive composition of the present invention has flexibility that can follow the shrinkage of the polarizing plate over time, and thus has excellent light leakage resistance. In addition, since the pressure-sensitive adhesive composition of the present invention has excellent durability, the pressure-sensitive adhesive layer hardly floats or peels off by heat treatment or high-humidity treatment.

  The present invention includes 0 to 9 parts by weight of a carboxyl group-containing monomer, 0 to 1.8 parts by weight of a hydroxy group-containing (meth) acrylic monomer, and 99.9 to 89.2 parts by weight of a (meth) acrylic acid ester monomer. (However, the total amount of the carboxyl group-containing monomer and the hydroxy group-containing (meth) acrylic monomer is not 0 parts by mass), and the (meth) acrylic copolymer has a weight average molecular weight of 1,000,000 to 2,000,000. 100 parts by mass; and a pressure-sensitive adhesive composition containing 0.05 to 5 parts by mass of a carbodiimide-based crosslinking agent. The present invention is characterized in that the amount of the hydroxy group-containing (meth) acrylic monomer constituting the (meth) acrylic copolymer is 1.8% by mass or less based on the total amount of monomers of the copolymer. And By controlling the amount of the hydroxy group-containing (meth) acrylic monomer in this way, the adhesive layer can be provided with a flexibility that can follow the shrinkage of the polarizing plate over time, and the adhesive layer is excellent. Light leakage resistance and durability can be imparted. Further, the present invention is characterized by using a carbodiimide-based crosslinking agent as a crosslinking agent. As a result, the (meth) acrylic copolymer can be cross-linked linearly with an appropriate degree of cross-linking, and the adhesive layer has flexibility and durability that can follow the shrinkage of the polarizing plate over time. It is possible to provide a cross-linked structure having an excellent light leakage resistance to the adhesive layer. For this reason, the pressure-sensitive adhesive layer formed using the pressure-sensitive adhesive composition of the present invention exhibits excellent light leakage resistance as a pressure-sensitive adhesive for optical members. In addition, since the pressure-sensitive adhesive layer formed using the pressure-sensitive adhesive composition of the present invention has excellent durability, the pressure-sensitive adhesive layer hardly floats or peels off by heat treatment or high-humidity treatment.

  Hereinafter, each component of the pressure-sensitive adhesive composition of the present invention will be described in detail. In the present specification, “(meth) acrylate” is a general term for acrylate and methacrylate. Similarly, a compound containing (meth) such as (meth) acrylic acid is a general term for a compound having “meta” in the name and a compound not having “meta”.

(A) (Meth) acrylic copolymer (meth) acrylic copolymer used in the present invention (hereinafter also simply referred to as “component (A)”) is (a-1) a carboxyl group-containing monomer. 9 parts by mass, (a-2) hydroxy group-containing (meth) acrylic monomer 0 to 1.8 parts by mass, and (a-3) (meth) acrylic acid ester monomer 99.9 to 89.2 parts by mass (however, The total amount of the carboxyl group-containing monomer and the hydroxy group-containing (meth) acrylic monomer is not 0 part by mass). And the weight average molecular weight of this (meth) acrylic-type copolymer is 1 million-2 million.

(A-1) Carboxyl Group-Containing Monomer The carboxyl group-containing monomer according to the present invention (hereinafter also simply referred to as “component (a-1)”) is an unsaturated monomer having at least one carboxyl group in the molecule. . Specific examples of the carboxyl group-containing monomer include, but are not limited to, (meth) acrylic acid, maleic acid, maleic anhydride, fumaric acid, fumaric anhydride, crotonic acid, itaconic acid, itaconic anhydride, myristoleic acid, Examples include palmitoleic acid and oleic acid. These may be used alone or in combination of two or more.

  Of these, (meth) acrylic acid, maleic acid, maleic anhydride, fumaric acid, fumaric anhydride, crotonic acid, itaconic acid, and itaconic anhydride are preferred, and (meth) acrylic acid is more preferred.

  In this invention, the quantity of a carboxyl group-containing monomer is 0-9 mass parts, Preferably it is 0.1-8 mass parts, More preferably, it is 0.2-5 mass parts. When the amount used exceeds 9 parts by mass, the carboxyl group in the copolymer (A) becomes excessive, and the crosslinking point formed by the reaction between the carboxyl group and the carbodiimide-based crosslinking agent (B) becomes excessive. The softness | flexibility of the adhesive composition of this invention falls, and the light leak resistance of an adhesion layer falls.

(A-2) Hydroxy group-containing (meth) acrylic monomer The hydroxy group-containing (meth) acrylic monomer according to the present invention (hereinafter also simply referred to as “component (a-2)”) has a hydroxy group in the molecule. It is an acrylic monomer. Specific examples of the hydroxy group-containing (meth) acrylic monomer include, but are not limited to, 2-hydroxyethyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, and 1,6-hexanediol mono (meth) acrylate. , Pentaerythritol tri (meth) acrylate, dipentaerythritol penta (meth) acrylate, neopentyl glycol mono (meth) acrylate, trimethylolpropane di (meth) acrylate, trimethylolethanedi (meth) acrylate, 2-hydroxypropyl ( (Meth) acrylate, 2-hydroxybutyl (meth) acrylate, 2-hydroxy-3-phenyloxypropyl (meth) acrylate, 4-hydroxycyclohexyl (meth) acrylate, N-2-hydroxy Examples include ethyl (meth) acrylamide, cyclohexanedimethanol monoacrylate and the like, and further obtained by addition reaction of glycidyl group-containing compounds such as alkyl glycidyl ether, allyl glycidyl ether, glycidyl (meth) acrylate and (meth) acrylic acid. And the like. These may be used alone or in combination of two or more.

  Among these, 2-hydroxyethyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, 2-hydroxyethyl (meth) acrylamide, and cyclohexane dimethanol monoacrylate are preferable, and 2-hydroxyethyl (meth) acrylate, 4- Hydroxybutyl (meth) acrylate and N-2-hydroxyethyl (meth) acrylamide are more preferred.

  The usage-amount of a hydroxyl-group-containing acrylic monomer is 0-1.8 mass part, Preferably it is 0.1-1.5 mass part, More preferably, it is 0.1-1.4 mass part. When the amount used exceeds 1.8 parts by mass, the hydroxyl groups in the copolymer (A) become excessive, and the crosslinking points formed by the reaction between the hydroxyl groups and the carbodiimide-based crosslinking agent (B) become excessive. Therefore, the softness | flexibility of the adhesive composition of this invention falls, and the light leakage resistance and durability of an adhesion layer fall.

(A-3) (meth) acrylic acid ester monomer (meth) acrylic acid ester monomer (hereinafter also simply referred to as “component (a-3)”) is a (meth) acrylic acid having no hydroxy group in the molecule. Ester. Specific examples of the (meth) acrylic acid ester monomer include, but are not limited to, methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, isopropyl (meth) acrylate, and n-butyl (meth) acrylate. , Isobutyl (meth) acrylate, tert-butyl (meth) acrylate, isoamyl (meth) acrylate, n-hexyl (meth) acrylate, n-heptyl (meth) acrylate, n-octyl (meth) acrylate, tert-octyl (meth) ) Acrylate, 2-ethylhexyl (meth) acrylate, decyl (meth) acrylate, isodecyl (meth) acrylate, tridecyl (meth) acrylate, stearyl (meth) acrylate, isostearyl (meth) acrylate , Phenyl (meth) acrylate, benzyl (meth) acrylate, dodecyl (meth) acrylate, tetrahydrofurfuryl (meth) acrylate, cyclohexyl (meth) acrylate, 4-n-butylcyclohexyl (meth) acrylate, 2-ethylhexyl diglycol ( (Meth) acrylate, butoxyethyl (meth) acrylate, butoxymethyl (meth) acrylate, 3-methoxybutyl (meth) acrylate, 2- (2-methoxyethoxy) ethyl (meth) acrylate, 2- (2-butoxyethoxy) ethyl (Meth) acrylate, 4-butylphenyl (meth) acrylate, phenyl (meth) acrylate, 2,4,5-tetramethylphenyl (meth) acrylate, phenoxymethyl (meth) acrylate, Xylethyl (meth) acrylate, polyethylene oxide monoalkyl ether (meth) acrylate, polyethylene oxide monoalkyl ether (meth) acrylate, polypropylene oxide monoalkyl ether (meth) acrylate, trifluoroethyl (meth) acrylate, pentadecafluorooxyethyl ( Examples include meth) acrylate, 2-chloroethyl (meth) acrylate, 2,3-dibromopropyl (meth) acrylate, and tribromophenyl (meth) acrylate. These may be used alone or in combination of two or more.

  Among these, methyl (meth) acrylate, ethyl (meth) acrylate, n-butyl (meth) acrylate, and 2-ethylhexyl (meth) acrylate are preferable, and methyl (meth) acrylate, n-butyl (meth) acrylate, 2- Ethylhexyl (meth) acrylate is more preferred.

  The amount of the (meth) acrylic acid ester monomer is 99.9 to 89.2 parts by mass, preferably 99.8 to 90.5 parts by mass, and 99.7 to 93.6 parts by mass. It is more preferable.

  The production method of the (meth) acrylic copolymer (A) is not particularly limited, and is a solution polymerization method using a polymerization initiator, an emulsion polymerization method, a suspension polymerization method, a reverse phase suspension polymerization method, and a thin film polymerization method. Conventionally known methods such as spray polymerization can be used. Examples of the polymerization control method include adiabatic polymerization, temperature controlled polymerization, and isothermal polymerization. In addition to the method of initiating polymerization with a polymerization initiator, a method of initiating polymerization by irradiating with radiation, electron beam, ultraviolet rays or the like can also be employed. Among these, the solution polymerization method using a polymerization initiator is preferable because the molecular weight can be easily adjusted and impurities can be reduced. For example, using ethyl acetate, toluene, methyl ethyl ketone or the like as a solvent, and preferably adding 0.01 to 0.50 parts by weight of a polymerization initiator with respect to 100 parts by weight of the total amount of monomers, It is obtained by reacting at a reaction temperature of 60 to 90 ° C. for 3 to 10 hours. Examples of the polymerization initiator include azo compounds such as azobisisobutyronitrile (AIBN), 2,2′-azobis (2-methylbutyronitrile), azobiscyanovaleric acid; tert-butyl peroxypivalate, organic peroxides such as tert-butylperoxybenzoate, tert-butylperoxy-2-ethylhexanoate, di-tert-butyl peroxide, cumene hydroperoxide, benzoyl peroxide, tert-butyl hydroperoxide; Examples thereof include inorganic peroxides such as hydrogen peroxide, ammonium persulfate, potassium persulfate, and sodium persulfate. These may be used alone or in combination of two or more.

  If necessary, other monomers copolymerizable with the components (a-1) to (a-3) are used. Other monomers are not particularly limited, and specific examples include acrylic monomers having an epoxy group such as glycidyl (meth) acrylate and methylglycidyl (meth) acrylate; dimethylaminoethyl (meth) acrylate, diethylaminoethyl Acrylic monomers having an amino group such as (meth) acrylate, N-tert-butylaminoethyl (meth) acrylate, methacryloxyethyltrimethylammonium chloride (meth) acrylate; (meth) acrylamide, N-methylol (meth) acrylamide, Acrylic monomers having an amide group such as N-methoxymethyl (meth) acrylamide and N, N-methylenebis (meth) acrylamide; 2-methacryloyloxyethyl diphenyl phosphate ) Acrylic monomers having a phosphate group such as acrylate, trimethacryloyloxyethyl phosphate (meth) acrylate, triacryloyloxyethyl phosphate (meth) acrylate; sulfopropyl (meth) acrylate sodium, 2-sulfoethyl (meth) acrylate sodium, Acrylic monomers having a sulfonic acid group such as sodium 2-acrylamido-2-methylpropanesulfonate; acrylic monomers having a urethane group such as urethane (meth) acrylate; p-tert-butylphenyl (meth) acrylate, o- Acrylic vinyl monomers having a phenyl group such as biphenyl (meth) acrylate; 2-acetoacetoxyethyl (meth) acrylate, vinyltrimethoxysilane, vinyltri Vinyl monomers having silane groups such as toxisilane, vinyltris (β-methoxyethyl) silane, vinyltriacetylsilane, methacryloyloxypropyltrimethoxysilane; styrene, chlorostyrene, α-methylstyrene, vinyltoluene, vinyl chloride, vinyl acetate, propion Examples include vinyl acid, acrylonitrile, vinyl pyridine and the like. These other monomers may be used alone or in combination of two or more.

  Among these other monomers, (meth) acrylamide, glycidyl (meth) acrylate, dimethylaminoethyl (meth) acrylate, and 2-acetoacetoxyethyl (meth) acrylate are preferable, (meth) acrylamide, dimethylaminoethyl (meth) An acrylate and 2-acetoacetoxyethyl (meth) acrylate are more preferable.

  The amount of other monomers used is preferably 0.1 to 10 parts by mass with respect to 100 parts by mass of the total amount of components (a-1) to (a-3). More preferably, it is -5 mass parts, and it is especially preferable that it is 0.3-2 mass parts.

  The weight average molecular weight (Mw) of the (meth) acrylic copolymer (A) obtained by copolymerizing the above components is 1,000,000 to 2,000,000, preferably 1.1 million to 1,800,000, more preferably. Is 1.2 million to 1.7 million. When the weight average molecular weight is less than 1 million, heat resistance is insufficient. On the other hand, when the weight average molecular weight exceeds 2 million, the tack is low and the bonding property is lowered. In addition, in this invention, the value of polystyrene conversion measured by the method as described in an Example shall be employ | adopted for a weight average molecular weight.

  In addition, the sum total of the usage-amount of the said component (a-1) and a component (a-2) is not 0 mass part. That is, at least one of the structural unit derived from the component (a-1) and the structural unit derived from the component (a-2) is necessarily contained in the (meth) acrylic copolymer (A). Means. Preferably, the total amount of component (a-1), component (a-2) and component (a-3) is 100 parts by mass.

  The component (A) may be used alone or in combination of two or more polymers.

(B) Carbodiimide-based crosslinking agent In addition to the component (A), the pressure-sensitive adhesive composition of the present invention contains a carbodiimide-based crosslinking agent (hereinafter also simply referred to as “component (B)”). A carbodiimide type crosslinking agent reacts and couple | bonds with the hydroxyl group and / or carboxyl group in said (meth) acrylic-type copolymer (A), and forms a crosslinked structure.

  The carbodiimide type crosslinking agent (B) used in the present invention is not particularly limited. Specifically, for example, a compound having two or more carbodiimide groups (—N═C═N—) in the molecule is preferably used, and a known polycarbodiimide can be used.

  Moreover, as a carbodiimide compound, the high molecular weight polycarbodiimide produced | generated by carrying out the decarboxylation condensation reaction of diisocyanate in presence of a carbodiimidization catalyst can also be used.

  Examples of such compounds include those obtained by subjecting the following diisocyanates to a decarboxylation condensation reaction.

  As the diisocyanate, 4,4′-diphenylmethane diisocyanate, 3,3′-dimethoxy-4,4′-diphenylmethane diisocyanate, 3,3′-dimethyl-4,4′-diphenylmethane diisocyanate, 4,4′-diphenyl ether diisocyanate, 3,3′-dimethyl-4,4′-diphenyl ether diisocyanate, 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, 1-methoxyphenyl-2,4-diisocyanate, isophorone diisocyanate, 4,4′- One of dicyclohexylmethane diisocyanate and tetramethylxylylene diisocyanate, or a mixture of two or more thereof can be used.

  As the carbodiimidization catalyst, 1-phenyl-2-phospholene-1-oxide, 3-methyl-2-phospholene-1-oxide, 1-ethyl-3-methyl-2-phospholene-1-oxide, 1-ethyl- Phosphorene oxides such as 2-phospholene-1-oxide or their 3-phospholene isomers can be used.

  Such a high molecular weight polycarbodiimide may be synthesized or a commercially available product may be used. Examples of commercially available components (B) include Carbodilite (registered trademark) series manufactured by Nisshinbo Chemical Co., Ltd. Among these, Carbodilite (registered trademark) V-01, V-03, V-05, V-07, and V-09 are preferable because of excellent compatibility with organic solvents.

  In this invention, the compounding quantity of a component (B) is 0.05-5 mass parts with respect to 100 mass parts of components (A). If it exists in this range, a moderate crosslinked structure can be formed and the outstanding heat resistance can further be achieved. When the blending amount of the carbodiimide crosslinking agent (B) is less than 0.05 parts by mass, a sufficient crosslinked structure cannot be formed and heat resistance is lowered. On the other hand, when the amount exceeds 5 parts by mass, the crosslinking reaction proceeds excessively, the adhesive strength is reduced, and it becomes impossible to follow the shrinkage of the polarizing plate over time, and the light leakage resistance and durability are lowered. The blending amount is more preferably 0.1 to 4 parts by mass, and still more preferably 0.1 to 3 parts by mass.

(C) Isocyanate-based crosslinking agent In addition to the above components (A) and (B), the pressure-sensitive adhesive composition of the present invention comprises an isocyanate-based crosslinking agent (C) (hereinafter also simply referred to as “component (C)”). It is preferable to include. By adding an isocyanate type crosslinking agent (C), the light leakage resistance and durability of the adhesive layer obtained are improved more.

  The component (C) used in the present invention is not particularly limited. Specifically, for example, triallyl isocyanate, dimer acid diisocyanate, 2,4-tolylene diisocyanate (2,4-TDI), 2,6-tolylene diisocyanate (2,6-TDI), 4,4′- Diphenylmethane diisocyanate (4,4′-MDI), 2,4′-diphenylmethane diisocyanate (2,4′-MDI), 1,4-phenylene diisocyanate, xylylene diisocyanate (XDI), tetramethylxylidene diisocyanate (TMXDI), Aromatic diisocyanates such as tolidine diisocyanate (TODI) and 1,5-naphthalene diisocyanate (NDI); hexamethylene diisocyanate (HDI), trimethylhexamethylene diisocyanate (TMHDI), lysine diisocyanate Aliphatic diisocyanates such as norbornane diisocyanate methyl (NBDI); transcyclohexane-1,4-diisocyanate, isophorone diisocyanate (IPDI), H6-XDI (hydrogenated XDI), H12-MDI (hydrogenated MDI), etc. Alicyclic diisocyanates; carbodiimide-modified diisocyanates of the above diisocyanates; or their isocyanurate-modified diisocyanates. Moreover, the adduct body of said isocyanate compound and polyol compounds, such as a trimethylol propane, the biuret body and isocyanurate body of these isocyanate compounds can also be used conveniently.

  The component (C) may be synthesized or a commercially available product may be used. Examples of commercially available components (C) include Coronate (registered trademark) L, Coronate (registered trademark) HL, Coronate (registered trademark) 2030, Coronate (registered trademark) 2031 (manufactured by Nippon Polyurethane Industry Co., Ltd.), Takenate (registered trademark) D-102, Takenate (registered trademark) D-110N, Takenate (registered trademark) D-200, Takenate (registered trademark) D-202 (manufactured by Mitsui Chemicals Polyurethane Co., Ltd.), Duranate (trademark) 24A-100, Duranate (TM) TPA-100, Duranate (TM) TKA-100, Duranate (TM) P301-75E, Duranate (TM) E402-90T, Duranate (TM) E405-80T, Duranate (TM) TSE- 100, Duranate ™ D-101, Du Sulfonate (TM) D-201 (above, Asahi Kasei Chemicals Co., Ltd.).

  Among these components (C), Coronate (registered trademark) L, Coronate (registered trademark) HL, Takenate (registered trademark) D110N, Duranate (trademark) 24A-100 are preferable, and Coronate (registered trademark) L, Takenate (registered trademark). ) D110N is more preferable, and Coronate (registered trademark) L is particularly preferable. In addition, these components (C) may be used independently and may be used in combination of 2 or more type.

  It is preferable that the usage-amount in the case of using a component (C) is 0.05-5 mass parts with respect to 100 mass parts of components (A). Within this range, the pressure-sensitive adhesive composition of the present invention can have excellent light leakage resistance and durability. The blending amount is more preferably 0.1 to 4 parts by mass, and still more preferably 0.15 to 3 parts by mass.

  The pressure-sensitive adhesive composition of the present invention may contain a silane coupling agent in addition to the above components. By using a silane coupling agent, the reactivity is improved, and the mechanical strength and adhesive strength of the crosslinked product can be improved. Such a silane coupling agent is not particularly limited. Specifically, for example, methyltrimethoxysilane, dimethyldimethoxysilane, trimethylmethoxysilane, n-propyltrimethoxysilane, ethyltrimethoxysilane, diethyldiethoxysilane, n-butyltrimethoxysilane, n-hexyltriethoxysilane , N-octyltrimethoxysilane, phenyltrimethoxysilane, diphenyldimethoxysilane, cyclohexylmethyldimethoxysilane, vinyltrichlorosilane, vinyltrimethoxysilane, vinyltriethoxysilane, vinyltris (β-methoxyethoxy) silane, β- (3 4-epoxycyclohexyl) ethyltrimethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropyltriethoxysilane, γ-methacryloxypropylme Tildimethoxysilane, γ-methacryloxypropyltrimethoxysilane, γ-methacryloxypropylmethyldiethoxysilane, γ-methacryloxypropyltriethoxysilane, γ-acryloxypropyltrimethoxysilane, N-β- (aminoethyl)- γ-aminopropylmethyldimethoxysilane, N-β- (aminoethyl) -γ-aminopropyltrimethoxysilane, N-β- (aminoethyl) -γ-aminopropyltriethoxysilane, γ-aminopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, N-phenyl-γ-aminopropyltrimethoxysilane, γ-chloropropyltrimethoxysilane, γ-mercaptopropyltrimethoxysilane, γ-mercaptopropylmethyldimethoxysilane, bis- (3- [ bird Tokishishiriru] propyl) tetrasulfide, .gamma. isocyanatepropyltriethoxysilane and the like. Further, a silane coupling agent having a functional group such as an epoxy group (glycidoxy group), an amino group, a mercapto group, or a (meth) acryloyl group, and a functional group having reactivity with these functional groups. A compound having a hydrolyzable silyl group obtained by reacting an agent, another coupling agent, polyisocyanate and the like with each functional group in an arbitrary ratio can also be used.

  The silane coupling agent may be synthesized or a commercially available product may be used. Examples of commercially available silane coupling agents include KBM-303, KBM-403, KBE-402, KBM-403, KBE-502, KBE-503, KBM-5103, KBM-573, KBM-802, and KBM-. 803, KBE-846, KBE-9007 (manufactured by Shin-Etsu Chemical Co., Ltd.) and the like.

  Among these silane coupling agents, KBM-303, KBM-403, KBE-402, KBM-403, KBM-5103, KBM-573, KBM-802, KBM-803, KBE-846, and KBE-9007 are preferable. KBM-403 is more preferred. In addition, the said silane coupling agent may be used independently and may be used in combination of 2 or more types.

  In the present invention, the amount of the silane coupling agent used is not particularly limited. Specifically, the blending amount of the silane coupling agent is preferably 0 to 1 part by mass, more preferably 0 to 0.5 part per 100 parts by mass of the total amount of the components (A) to (C). Part by mass, more preferably 0 to 0.1 part by mass. If it exists in this range, the outstanding heat resistance and adhesiveness can be exhibited. When the compounding quantity of the said silane coupling agent (C) exceeds 1 mass part, heat resistance may fall.

  In addition to the silane coupling agent or in place of the silane coupling agent, the pressure-sensitive adhesive composition of the present invention comprises a curing accelerator, an ionic liquid, a lithium salt, an inorganic filler, a softening agent, an antioxidant, and aging. Inhibitors, stabilizers, tackifying resins, modified resins (polyol resins, phenol resins, acrylic resins, polyester resins, polyolefin resins, epoxy resins, epoxidized polybutadiene resins, etc.), leveling agents, antifoaming agents, plasticizers, dyes , Additives such as pigments (colored pigments, extender pigments, etc.), treatment agents, UV blockers, fluorescent brighteners, dispersants, heat stabilizers, light stabilizers, UV absorbers, antistatic agents, lubricants and solvents May be included. Among these, examples of the curing accelerator include dibutyltin dilaurate, JCS-50 (manufactured by Johoku Chemical Industry Co., Ltd.), formate TK-1 (manufactured by Mitsui Chemical Polyurethane Co., Ltd.), and the like. Examples of the ionic liquid include phosphonium ion, pyridinium ion, pyrrolidinium ion, imidazolium ion, guanidinium ion, ammonium ion, isouronium ion, thiouronium ion, piperidinium ion, pyrazolium ion, sulfonium ion, and the like. As cation component and anion component, halogen ion, nitrate ion, sulfate ion, phosphate ion, perchlorate ion, thiocyanate ion, thiosulfate ion, sulfite ion, tetrafluoroborate ion, hexafluorophosphate ion, formate ion, And substances having an anion component such as oxalate ion, acetate ion, trifluoroacetate ion, and alkylsulfonate ion. Examples of the antioxidant include dibutylhydroxytoluene (BHT), Irganox (registered trademark) 1010, Irganox (registered trademark) 1035FF, Irganox (registered trademark) 565 (all manufactured by Ciba Specialty Chemicals) and the like. Can be mentioned. Examples of the tackifying resin include rosins such as rosin acid, polymerized rosin acid and rosin acid ester, terpene resin, terpene phenol resin, aromatic hydrocarbon resin, aliphatic saturated hydrocarbon resin and petroleum resin. Although the usage-amount of an additive in the case of using the said additive is not restrict | limited in particular, For example, it is 0.1-20 mass parts with respect to 100 mass parts of total amounts of the said component (A)-(C). is there.

  The pressure-sensitive adhesive composition of the present invention can be prepared by mixing the above-described components all together, mixing each component sequentially, or mixing any plural components and then mixing the remaining components. It can manufacture by stirring so that it may become a uniform mixture. More specifically, it can be prepared by heating, for example, to a temperature of 30 to 40 ° C. as necessary, and stirring for 10 minutes to 5 hours until it becomes uniform with a stirrer or the like.

  The pressure-sensitive adhesive composition of the present invention can be used for bonding various substrates. Examples of the substrate that can be used here include glass, plastic film, paper, and metal foil. Examples of the glass include general inorganic glass. Examples of the plastic in the plastic film include polyvinyl chloride resin, polyvinylidene chloride, cellulose resin, acrylic resin, cycloolefin resin, amorphous polyolefin resin, polyethylene, polypropylene, polystyrene, ABS resin, polyamide, and polyester. , Polycarbonate, polyurethane, polyvinyl alcohol, ethylene-vinyl acetate copolymer and chlorinated polypropylene. The amorphous polyolefin-based resin usually has a polymerization unit of a cyclic polyolefin such as norbornene or a polycyclic norbornene-based monomer, and may be a copolymer of a cyclic olefin and a chain cyclic olefin. Commercially available non-crystalline polyolefin resins such as Arton from JSR Corporation, ZEONEX (registered trademark) from ZEON Corporation, ZEONOR (registered trademark), APO from Mitsui Chemicals, Apel (registered trademark), etc. There is. In order to form an amorphous polyolefin-based resin into a film, a known method such as a solvent casting method or a melt extrusion method is appropriately used. Examples of the paper include imitation paper, fine paper, craft paper, art coated paper, caster coated paper, pure white roll paper, parchment paper, water resistant paper, glassine paper, and corrugated paper. Examples of the metal foil include aluminum foil.

  Therefore, this invention also provides an optical member provided with the adhesion layer formed from the adhesive composition of this invention.

  Preferred examples of the optical member include a polarizing plate, a retardation plate, an optical film for plasma display, and a conductive film for touch panel. Among these, the adhesive composition of this invention is excellent in the adhesiveness of a polarizing plate and glass. Of course, the present invention is not limited to the above-described form, and can be used for bonding other members.

  The pressure-sensitive adhesive composition of the present invention may be used by directly applying to one side or both sides of an optical member to form a pressure-sensitive adhesive layer, or by previously forming a pressure-sensitive adhesive layer on a release film. It may be used by transferring to one side or both sides.

  Coating of the pressure-sensitive adhesive composition of the present invention may be performed by a conventionally known method, for example, natural coater, knife belt coater, floating knife, knife over roll, knife on blanket, spray, dip, kiss roll, squeeze roll, Various coating methods using apparatuses such as a reverse roll, an air blade, a curtain flow coater, a doctor blade, a wire bar, a die coater, a comma coater, a baker applicator, and a gravure coater may be mentioned. Moreover, what is necessary is just to select the application | coating thickness (thickness after drying) of the adhesive composition of this invention according to the base material to be used and a use, Preferably it is 5-30 micrometers, More preferably, 15- 25 μm.

  The viscosity of the pressure-sensitive adhesive composition of the present invention is not particularly limited. However, considering the ease of coating and the ease of controlling the thickness of the adhesive layer formed from the composition, the viscosity at 25 ° C. is preferably 500 to 5000 mPa · s, more preferably 1000 to 3000 mPa · s.

  The pressure-sensitive adhesive layer obtained from the pressure-sensitive adhesive composition of the present invention is obtained by crosslinking the pressure-sensitive adhesive composition as described above. At that time, the pressure-sensitive adhesive composition is generally crosslinked after application of the pressure-sensitive adhesive composition, but it is also possible to transfer a pressure-sensitive adhesive layer comprising the pressure-sensitive adhesive composition after crosslinking to a substrate or the like. . Crosslinking of this pressure-sensitive adhesive composition is usually carried out by allowing it to stand under conditions of a temperature of 20 to 40 ° C., a relative humidity of 30 to 70% RH, and normal pressure (atmospheric pressure).

  Since the pressure-sensitive adhesive composition of the present invention exhibits excellent flexibility, particularly when used in a polarizing plate, it can follow the shrinkage of the polarizing plate over time and can obtain excellent light leakage resistance.

  In addition, since the pressure-sensitive adhesive composition of the present invention has excellent durability, the pressure-sensitive adhesive layer hardly floats or peels off by heat treatment or high-humidity treatment.

  The effects of the present invention will be described using the following examples and comparative examples. However, the technical scope of the present invention is not limited only to the following examples.

  The solid content and viscosity of the polymer solution obtained in the synthesis example and the weight average molecular weight of the polymer (A) were measured by the following method.

<Solid content>
About 1 g of the polymer solution is precisely weighed in a precisely weighed glass dish. After drying at 105 ° C. for 1 hour, the temperature is returned to room temperature, and the total mass of the glass dish and the remaining solid is precisely weighed. The solid content was calculated by the following formula 1, where X is the mass of the glass plate, Y is the total mass of the glass plate before drying and the polymer solution, and Z is the total mass Z of the glass plate and the remaining solid content.

<Viscosity>
The polymer solution in a glass bottle was temperature-controlled at 25 ° C. and measured with a B-type viscometer.

<Weight average molecular weight>
The measurement was performed according to the measurement method and measurement conditions shown in Table 1 below.

(Synthesis Example 1)
99 parts by mass of n-butyl acrylate (manufactured by Nippon Shokubai Co., Ltd.), 1 part by weight of 2-hydroxyethyl acrylate (manufactured by Nippon Shokubai Co., Ltd.), and 120 parts by mass of ethyl acetate were charged into a flask equipped with a reflux condenser and a stirrer. . Next, the mixture was heated to 65 ° C. while performing nitrogen substitution, 0.04 parts by mass of azobisisobutyronitrile (AIBN) was added, and polymerization was performed for 6 hours while maintaining 65 ° C. After the completion of the polymerization reaction, 280 parts by mass of ethyl acetate was added for dilution to obtain a polymer (sample name: A-1) solution. The obtained polymer solution had a solid content of 20% by mass and a viscosity of 4500 mPa · s. Moreover, the weight average molecular weight of the obtained polymer (A-1) was 1,600,000.

(Synthesis Examples 2 to 18)
By performing the same operation as in Synthesis Example 1 except that the composition of the monomer component was changed to the composition shown in Table 1 in Synthesis Example 1, the polymer (A-2) to A solution of (A-18) was obtained. Moreover, the solid content and viscosity of the obtained polymer (A-2)-(A-18) solution, and the weight average molecular weight of polymer (A-2)-(A-18) were measured. The results are shown in Table 2 below. In Table 2 below, “BA” is butyl acrylate; “2EHA” is 2-ethylhexyl acrylate; “HEA” is 2-hydroxyethyl acrylate; “4HBA” is 4-hydroxy “HEAA” is N-2-hydroxyethylacrylamide; “AA” is acrylic acid.

Example 1
500 parts by mass of the polymer solution obtained in Synthesis Example 1 (100 parts by mass as the solid content of the polymer), Carbodilite (registered trademark) V-01 (Nisshinbo Chemical Co., Ltd.), which is a carbodiimide-based crosslinking agent (B) , Sample name B-1) 1 part by mass, Coronate (registered trademark) L (trimethylolpropane / tolylene diisocyanate trimer adduct, which is an isocyanate crosslinking agent (C), manufactured by Nippon Polyurethane Industry Co., Ltd., sample name C -1) 0.2 part by mass and KBM-403 (3-glycidoxypropylmethyldiethoxysilane, manufactured by Shin-Etsu Chemical Co., Ltd.) which is a silane coupling agent 0.1 part by mass at room temperature (25 ° C.) The mixture was mixed for 10 minutes to obtain a solution in which the pressure-sensitive adhesive composition was dissolved.

  This solution was applied onto a peeled PET film (MRF38, manufactured by Mitsubishi Chemical Polyester Film Co., Ltd., thickness: 38 μm) so that the thickness after drying was 25 μm, and dried at 90 ° C. for 3 minutes to form an adhesive layer After forming the film, it was bonded to a polarizing plate to prepare a polarizing plate with an adhesive layer.

(Examples 2 to 10, Comparative Examples 1 to 8)
In the composition ratio as shown in Table 2 below, the polymers synthesized in the above synthesis examples, carbodiimide crosslinking agents, isocyanate crosslinking agents, carbodiimide crosslinking agents and other crosslinking agents other than isocyanate crosslinking agents, and silane couplings Except having used the agent, it carried out similarly to Example 1, and prepared the solution in which the adhesive composition was melt | dissolving, and preparation of the polarizing plate with an adhesive layer. The details of the carbodiimide-based crosslinking agents B-2 and B-3 and other crosslinking agents D-1 are as shown in Table 3 below.

  About the polarizing plate with an adhesive layer of Examples 1-10 and Comparative Examples 1-8 obtained as mentioned above, each performance was evaluated according to the following method.

1. Metal corrosion inhibition / prevention property The adhesive layer surface of each surface protective film that was allowed to stand for 7 days in an atmosphere of 23 ° C. and 50% RH was bonded to an aluminum foil, and left for 2 days in an atmosphere of 60 ° C. and 90% RH. The corrosivity at that time was observed. In Table 4 below, “◯” indicates no change, and “x” indicates whitening.

2. Light leakage resistance A polarizing plate having an adhesive layer left for 7 days in an atmosphere of 23 ° C. and 50% RH is cut into 120 mm (polarizing plate MD direction) × 60 mm and 120 mm (polarizing plate TD direction) × 60 mm, The glass plates were laminated so as to overlap each other, and autoclaved for 20 minutes at 50 ° C. and 0.49 MPa (5 kg / cm ² ). Thereafter, the appearance after being allowed to stand for 120 hours and 500 hours in an 80 ° C. atmosphere was observed. In Table 4 below, “◎” indicates that no light leakage was observed after 120 hours and 500 hours, “◯” indicates that no light leakage was observed after 120 hours, and “×” indicates that light leakage was not observed. It represents what was observed.

3. Durability A polarizing plate having an adhesive layer that was allowed to stand for 7 days in an atmosphere of 23 ° C. and 50% RH was cut into 120 mm (polarizing plate MD direction) × 60 mm, and bonded to a glass plate. The autoclave process was performed for 20 minutes on 49 MPa (5 kg / cm < ² >) conditions. Thereafter, the appearance after leaving for 120 hours in an atmosphere of 100 ° C. or 80 ° C. and 90% RH was observed. In Table 4 below, “◯” represents that foaming, floating, and peeling were not observed, and “X” represents that foaming, floating, and peeling were observed.

4). Adhesive strength A polarizing plate having an adhesive layer left for 7 days in an atmosphere of 23 ° C. and 50% RH is cut to a width of 25 mm and bonded to a glass plate, and the conditions are 50 ° C. and 0.49 MPa (5 kg / cm ² ). Under the autoclave treatment for 20 minutes. Using a tensile tester in an atmosphere of 23 ° C. and 50% RH at a peeling angle of 90 degrees and a peeling speed of 0.3 m / min, according to the adhesive tape / adhesive sheet test method described in JIS Z0237 (2000). The adhesive strength was measured.

5. 3. Adhesiveness to substrate The adhesion was observed when measuring the adhesive strength. In Table 4 below, “◯” represents that the pressure-sensitive adhesive was not peeled off from the substrate, and “x” represents that the pressure-sensitive adhesive was peeled off from the substrate.

6). Adherent contamination property 4. The contact angle of the glass plate surface before and after measuring the adhesive strength was measured. In Table 4 below, “◯” indicates that there was no change in the contact angle of the glass surface before and after the adhesive strength measurement, and “×” indicates that there was a change in the contact angle of the glass surface before and after the adhesive strength measurement. Represent.

7). Low temperature stability A polarizing plate having an adhesive layer left for 7 days in an atmosphere of 23 ° C. and 50% RH was cut into 120 mm (polarizing plate MD direction) × 60 mm, and bonded to a glass plate. Autoclave treatment was performed for 20 minutes under the condition of 49 MPa (5 kg / cm ² ). Then, the external appearance after leaving for 120 hours in -40 degreeC atmosphere was observed. In Table 4 below, “◯” represents that foaming, floating, peeling, and recrystallized material were not observed, and “X” represents foaming, floating, peeling, and recrystallized material were observed.

8). Reworkability 4. The peeled state was observed when measuring the adhesive strength. In Table 4 below, “◯” represents that interfacial fracture was observed, and “x” represents that the adhesive was transferred and / or cohesive fracture was observed on the glass plate (adhered body).

9. Gel fraction Instead of the polarizing plate having the pressure-sensitive adhesive layer prepared in each Example and Comparative Example, a peeled polyester film was used to measure the gel fraction after 7 days of coating. As for the gel fraction, about 0.1 g of the pressure-sensitive adhesive composition left in an atmosphere of 23 ° C. and 50% RH was weighed, and the weight W ₁ (g) was measured. This was collected in a sample bottle, and about 30 g of ethyl acetate was added and left for 24 hours. The contents of the sample bottle after a predetermined period of time were filtered off with a 200-mesh stainless steel wire mesh (the weight of the membrane was W ₂ (g)), and the wire mesh and the residue were dried at 90 ° C. for 1 hour. W ₃ (g) was measured. The gel fraction was calculated from these measured values according to the following mathematical formula 2.

  Each evaluation result is summarized and shown in Table 4 below. In addition, since the comparative example 6 in Table 4 was gelatinized at the time of manufacture of an adhesion layer, each evaluation was not able to be performed.

  As is apparent from Table 4 above, the polarizing plates (Examples 1 to 10) using the pressure-sensitive adhesive composition of the present invention use pressure-sensitive adhesive compositions (Comparative Examples 1 to 8) that are outside the scope of the present invention. Excellent light leakage resistance and durability compared to conventional polarizing plates. In particular, the light leakage resistance of the pressure-sensitive adhesive layers obtained from the pressure-sensitive adhesive compositions of Examples 1, 2, 3, 5, 6, 8, and 10 containing the isocyanate crosslinking agent (C) is further improved.

Claims (3)

It consists of 0 to 9 parts by weight of a carboxyl group-containing monomer, 0 to 1.8 parts by weight of a hydroxy group-containing (meth) acrylic monomer and 99.9 to 89.2 parts by weight of a (meth) acrylic acid ester monomer (however, , The total amount of the carboxyl group-containing monomer and the hydroxy group-containing (meth) acrylic monomer is not 0 part by mass), and the (meth) acrylic copolymer having a weight average molecular weight of 1,000,000 to 2,000,000 is 100 parts by mass; And a carbodiimide-based cross-linking agent, which contains 0.05 to 5 parts by mass, and has a gel fraction of 77 to 93% after 7 days of coating.   Furthermore, the adhesive composition of Claim 1 containing 0.05-5 mass parts of isocyanate type crosslinking agents.   An optical member provided with the adhesive layer formed from the adhesive composition of Claim 1 or 2.