JP2012097162A - Adhesive composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an adhesive composition which has a long pot life, excels in workability, attains to practical adhesive performance in a short aging time, and excels in productivity.SOLUTION: The adhesive composition includes: 100 pts.mass of a (meth)acrylic copolymer (A) having a weight average molecular weight of 100,000-2,000,000 and including a monomer component comprising 0-9 pts.mass of a carboxyl group-containing monomer (a-1), 0-9 pts.mass of a hydroxyl group-containing (meth)acrylic monomer (a-2), and 99.9-82 pts.mass of a (meth)acrylic acid ester monomer (a-3), a total amount of the carboxyl group-containing monomer (a-1) and the hydroxyl group-containing (meth)acrylic monomer (a-2) being greater than 0 pts.mass and a total amount of the carboxyl group-containing monomer (a-1), the hydroxyl group-containing (meth)acrylic monomer (a-2), and the (meth)acrylic acid ester monomer (a-3) being 100 pts.mass; 0.01-1 pts.mass of a peroxide crosslinking agent (B), based on 100 pts.mass of the (meth)acrylic copolymer (A); and 0.05-5 pts.mass of a carbodiimide crosslinking agent (C), based on 100 pts.mass of the (meth)acrylic copolymer (A).

Description

  The present invention relates to a pressure-sensitive adhesive composition. More specifically, the present invention relates to a pressure-sensitive adhesive composition having a long pot life and excellent workability, and reaching practical pressure-sensitive adhesive performance in a short aging time after pressure-sensitive adhesive processing.

  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, improvement of workability | operativity and productivity of the adhesive used for FPD is calculated | required.

  Patent Document 1 discloses an adhesive composition for an optical member containing an acrylic polymer, a peroxide and a silane coupling agent. The pressure-sensitive adhesive composition of Patent Document 1 exhibits high durability that does not cause peeling or foaming even under high temperature and high humidity conditions by blending an acrylic polymer with a peroxide and a silane coupling agent. There is an advantage that excellent productivity is exhibited without requiring aging after the drying / crosslinking process (paragraph “0021”).

Japanese Patent Laying-Open No. 2005-307034

  However, when the pressure-sensitive adhesive layer formed from the pressure-sensitive adhesive composition described in Patent Document 1 is examined, the pressure-sensitive adhesive layer can be shortened as compared with the conventional aging period, but after the pressure-sensitive adhesive processing, the pressure-sensitive adhesive layer has a practical pressure-sensitive adhesive performance. A specific aging time of at least 0.5 days is necessary until it is reached, and there has been a demand for further shortening in consideration of productivity.

  The present invention has been made in view of the above circumstances, and has an object to provide a pressure-sensitive adhesive composition having a long pot life, excellent workability, reaching practical adhesive performance in a short aging time, and excellent productivity. To do.

  The present inventors have intensively studied to solve the above problems. As a result, the pressure-sensitive adhesive composition containing a (meth) acrylic copolymer, a peroxide cross-linking agent and a carbodiimide cross-linking agent in a specific composition has a long pot life and excellent workability. Within 10 minutes), practical adhesive performance was reached, and it was found that productivity was greatly improved, and the present invention was completed.

  That is, the present invention comprises 0 to 9 parts by mass of a carboxyl group-containing monomer (a-1), 0 to 9 parts by mass of a hydroxy group-containing (meth) acrylic monomer (a-2) and 99.9 to 82 parts by mass. Consists of (meth) acrylic acid ester monomer (a-3) (however, the total amount of carboxyl group-containing monomer (a-1) and hydroxy group-containing (meth) acrylic monomer (a-2) is not 0 parts by mass) And the total amount of the carboxyl group-containing monomer (a-1), the hydroxy group-containing (meth) acrylic monomer (a-2), and the (meth) acrylic acid ester monomer (a-3) is 100 parts by mass) 100 parts by weight of a (meth) acrylic copolymer (A) containing a monomer component and having a weight average molecular weight of 100,000 to 2,000,000; 100 parts by weight of the (meth) acrylic copolymer (A) It is a pressure-sensitive adhesive composition containing 0.1 to 1 part by mass of a peroxide crosslinking agent (B) and 0.05 to 5 parts by mass of a carbodiimide crosslinking agent (C) with respect to parts.

  The pressure-sensitive adhesive composition of the present invention has a long pot life and excellent workability, reaches practical pressure-sensitive adhesive performance immediately after pressure-sensitive adhesive processing (within 10 minutes after completion of pressure-sensitive adhesive processing), and greatly improves productivity. Therefore, the pressure-sensitive adhesive composition of the present invention is effective for adhesion of various adherends, and the pressure-sensitive adhesive layer formed from the pressure-sensitive adhesive composition of the present invention is particularly suitable for optical members, surface protective films, and pressure-sensitive adhesive sheets. It can be suitably used as an adhesive layer.

  The present invention includes 0 to 9 parts by mass of a carboxyl group-containing monomer (a-1), 0 to 9 parts by mass of a hydroxy group-containing (meth) acrylic monomer (a-2), and 99.9 to 82 parts by mass of (meta ) Consisting of acrylic acid ester monomer (a-3) (however, the total amount of carboxyl group-containing monomer (a-1) and hydroxy group-containing (meth) acrylic monomer (a-2) is not 0 parts by mass, and The total amount of carboxyl group-containing monomer (a-1), hydroxy group-containing (meth) acrylic monomer (a-2), and (meth) acrylic acid ester monomer (a-3) is 100 parts by mass) monomer 100 parts by weight of (meth) acrylic copolymer (A) having a component and a weight average molecular weight of 100,000 to 2,000,000; with respect to 100 parts by weight of (meth) acrylic copolymer (A) The present invention provides a pressure-sensitive adhesive composition containing 0.1 to 1 part by mass of a peroxide crosslinking agent (B) and 0.05 to 5 parts by mass of a carbodiimide crosslinking agent (C).

  The pressure-sensitive adhesive composition of the present invention is characterized by containing a peroxide crosslinking agent and a carbodiimide crosslinking agent as a crosslinking agent. By using a peroxide cross-linking agent and a carbodiimide cross-linking agent together as a cross-linking agent, the pot life is long without affecting the physical properties of the adhesive, and practical adhesive performance immediately after the adhesive processing (within 10 minutes after completion of the adhesive processing) Thus, a pressure-sensitive adhesive composition with significantly improved workability and productivity can be obtained. For this reason, if the adhesive composition of this invention is used, it can apply as various uses, such as the adhesive for optical members, the adhesive for surface protection films, and the adhesive for adhesive sheets, which do not require an aging process.

  In addition, the pressure-sensitive adhesive layer formed using the pressure-sensitive adhesive composition of the present invention has an appropriate pressure-sensitive adhesive strength and adhesion to a substrate as a pressure-sensitive adhesive for optical members, and further suppresses / prevents metal corrosion. Excellent resistance, light leakage resistance, durability, adherend contamination resistance, low-temperature stability, and reworkability.

  Furthermore, the pressure-sensitive adhesive layer formed using the pressure-sensitive adhesive composition of the present invention has moderate adhesive strength and adhesion to a substrate as a surface protective film pressure-sensitive adhesive, and suppresses and prevents metal corrosion. It also has excellent resistance to adherend contamination, low temperature stability, and transparency, and suppresses and prevents foaming under high temperature and high pressure conditions (during autoclave treatment).

  In addition, the pressure-sensitive adhesive layer formed using the pressure-sensitive adhesive composition of the present invention has an appropriate pressure-sensitive adhesive strength and adhesiveness to the substrate as a pressure-sensitive adhesive for pressure-sensitive adhesive sheets, and further suppresses metal corrosion. Excellent in prevention, adherend resistance, low-temperature stability, transparency, heat resistance, and heat and humidity resistance.

  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”. For this reason, “(meth) acryl” includes both acrylic and methacrylic. “(Meth) acrylate” includes both acrylate and methacrylate. “(Meth) acrylic acid” includes both acrylic acid and methacrylic acid.

(A) (Meth) acrylic copolymer The (meth) acrylic copolymer (hereinafter also simply referred to as “component (A)”) used in the present invention is a carboxyl group-containing monomer (a-1) 0 to 9 mass. Part, a hydroxyl group containing (meth) acrylic monomer (a-2) 0-9 mass part, and the (meth) acrylic acid ester monomer (a-3) 99.9-82 mass part. The total amount of the carboxyl group-containing monomer (a-1) and the hydroxy group-containing (meth) acrylic monomer (a-2) is not 0 part by mass. Moreover, the total amount of a carboxyl group-containing monomer (a-1), a hydroxy group-containing (meth) acrylic monomer (a-2), and a (meth) acrylic acid ester monomer (a-3) is 100 parts by mass. And the weight average molecular weight of this (meth) acryl copolymer is 100,000-2 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 usage-amount of a carboxyl group-containing monomer is 0-9 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 crosslinking agent (C) becomes excessive. The flexibility of the pressure-sensitive adhesive composition of the invention is lowered, and the light leakage resistance and durability of the pressure-sensitive adhesive layer are lowered.

(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)”) is an acrylic having a hydroxy group in the molecule. 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, 1,6-hexanediol mono (meth) acrylate, Pentaerythritol tri (meth) acrylate, dipentaerythritol penta (meth) acrylate, neopentyl glycol mono (meth) acrylate, trimethylolpropane di (meth) acrylate, trimethylolethane di (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 til (meth) acrylamide, cyclohexanedimethanol monoacrylate, 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, N-2-hydroxyethyl (meth) acrylamide, and cyclohexanedimethanol 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 0-9 mass parts. If the amount used exceeds 9 parts by mass, the hydroxy group in the copolymer (A) becomes excessive, and the crosslinking point formed by the reaction between the hydroxy group and the carbodiimide crosslinking agent (C) becomes excessive. The flexibility of the pressure-sensitive adhesive composition of the invention is lowered, and the light leakage resistance and durability of the pressure-sensitive adhesive layer are lowered.

(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, propyl (meth) acrylate, isopropyl (meth) acrylate, n-butyl (meth) acrylate, and 2-ethylhexyl (meth) acrylate are preferable, and methyl (meth) An acrylate, n-butyl (meth) acrylate, and 2-ethylhexyl (meth) acrylate are more preferable.

  The amount of the (meth) acrylic acid ester monomer (a-3) used is 99.9 to 82 parts by mass.

  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, 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 amino groups such as (meth) acrylate, N-tert-butylaminoethyl (meth) acrylate, methacryloxyethyltrimethylammonium chloride (meth) acrylate; (meth) acrylamide, N-methylol (meth) acrylamide, N- Acrylic monomers having an amide group such as methoxymethyl (meth) acrylamide, N, N-methylenebis (meth) acrylamide; 2-methacryloyloxyethyl diphenyl phosphate (meth) a Acrylic monomers having a phosphate group such as relate, trimethacryloyloxyethyl phosphate (meth) acrylate, triacryloyloxyethyl phosphate (meth) acrylate; sulfopropyl (meth) acrylate sodium, 2-sulfoethyl (meth) acrylate sodium, 2- Acrylic monomer having a sulfonic acid group such as sodium acrylamido-2-methylpropanesulfonate; Acrylic monomer having a urethane group such as urethane (meth) acrylate; p-tert-butylphenyl (meth) acrylate, o-biphenyl (meth) Acrylic vinyl monomers having a phenyl group such as acrylate; 2-acetoacetoxyethyl (meth) acrylate, vinyltrimethoxysilane, vinyltriethoxysilane, Vinyl monomers having a silane group such as nitrotris (β-methoxyethyl) silane, vinyltriacetylsilane, methacryloyloxypropyltrimethoxysilane; styrene, chlorostyrene, α-methylstyrene, vinyltoluene, vinyl chloride, vinyl acetate, vinyl propionate , 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, 2-acetoacetoxyethyl (meth) acrylate and vinyl acetate are preferred, and (meth) acrylamide and vinyl acetate are preferred. More preferred.

  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 still more preferable that it is 0.3-3 mass parts.

  The weight average molecular weight (Mw) of the (meth) acrylic copolymer (A) obtained by copolymerizing the above components is 100,000 to 2,000,000. When the weight average molecular weight is less than 100,000, the 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 specification, the weight average molecular weight shall employ | adopt the value of polystyrene conversion measured by the method as described in an Example.

  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, the (meth) acrylic copolymer (A) always contains at least one of the structural unit derived from the component (a-1) and the structural unit derived from the component (a-2). means. And the total amount of a component (a-1), a component (a-2), and a component (a-3) shall be 100 mass parts.

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

(B) Peroxide crosslinking agent In addition to the component (A), the pressure-sensitive adhesive composition of the present invention contains a peroxide crosslinking agent (hereinafter, also simply referred to as “component (B)”). The peroxide crosslinking agent generates radicals by heating, performs hydrogen abstraction of the (meth) acrylic copolymer, generates radicals in the (meth) acrylic copolymer, and the parts react with each other, A crosslinked structure is formed.

  The peroxide crosslinking agent used in the present invention is not particularly limited. Specifically, for example, di (2-ethylhexyl) peroxydicarbonate, di (4-t-butylcyclohexyl) peroxydicarbonate, di-sec-butylperoxydicarbonate, t-butylperoxyneodecano Ate, t-hexyl peroxypivalate, t-butyl peroxypivalate, dilauroyl peroxide, di-n-octanoyl peroxide, 1,1,3,3-tetramethylbutylperoxy-2-ethylhexa Noate, di (4-methylbenzoyl) peroxide, benzoyl peroxide, t-butyl peroxybutyrate and the like.

  Among these, considering the crosslinking reaction efficiency, di (4-t-butylcyclohexyl) peroxydicarbonate, dilauroyl peroxide, and benzoyl peroxide are preferred, and di (4-t-butylcyclohexyl) peroxydicarbonate, More preferred is benzoyl peroxide.

  The compounding quantity of a component (B) is 0.1-1 mass part with respect to 100 mass parts of a component (A), More preferably, it is 0.2-0.8 mass part. 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 peroxide crosslinking agent (B) is less than 0.1 parts by mass, a sufficient crosslinked structure cannot be formed and heat resistance is lowered. On the other hand, when the amount exceeds 1 part by mass, the crosslinking reaction proceeds excessively, the adhesive force decreases, and it becomes impossible to follow the shrinkage of the polarizing plate over time, and light leakage resistance and durability are deteriorated.

  The said component (B) may be used independently and may be used in combination of 2 or more type.

(C) Carbodiimide crosslinking agent In addition to the components (A) and (B), the pressure-sensitive adhesive composition of the present invention includes a carbodiimide crosslinking agent (hereinafter, also simply referred to as “component (C)”). The carbodiimide crosslinking agent reacts and bonds with the hydroxy group and / or carboxyl group in the (meth) acrylic copolymer (A) to form a crosslinked structure.

  The carbodiimide crosslinking agent (C) 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 (C) 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.

  The said component (C) may be used independently and may be used in combination of 2 or more type.

  The compounding quantity of a component (C) 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. In addition, the crosslinking effect of the peroxide crosslinking agent can be promoted. For this reason, the pressure-sensitive adhesive composition of the present invention exhibits practical pressure-sensitive adhesive performance immediately after pressure-sensitive adhesive processing (within 10 minutes after completion of pressure-sensitive adhesive processing), and can greatly improve productivity. When the blending amount of the carbodiimide crosslinking agent (C) is less than 0.05 parts by mass, a sufficient crosslinked structure cannot be formed and heat resistance is lowered. In addition, it does not sufficiently promote the crosslinking effect of the peroxide crosslinking agent, and requires a specific aging (aging) time from the adhesive processing to reaching the practical adhesive performance. 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.

(D) Isocyanate crosslinking agent In addition to the above components (A), (B) and (C), the pressure-sensitive adhesive composition of the present invention comprises an isocyanate crosslinking agent (D) (hereinafter, also simply referred to as “component (D)”). ) May be included. By adding an isocyanate crosslinking agent (D), durability of the obtained adhesive layer can be improved more.

  The component (D) 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 (D) may be synthesized or a commercially available product may be used. Examples of commercially available components (D) 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, Inc.), Duranate (trademark) 24A -100, Duranate ™ TPA-100, Duranate ™ TKA-100, Duranate ™ P301-75E, Duranate ™ E402-90T, Duranate ™ E405-80T, Duranate ™ TSE-100 , Duranate (trademark) D-101, Duranate (trade) ) D-201 (above, include Asahi Kasei Chemicals Co., Ltd.).

  Among these components (D), Coronate (registered trademark) L, Coronate (registered trademark) HL, Takenate (registered trademark) D110N, Duranate (trademark) 24A-100, Duranate (trademark) TPA-100 are preferable, and Coronate (registered) (Trademark) L and Duranate (trademark) 24A-100 are more preferable.

  The said component (D) 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 (D) is 0.05-5 mass parts with respect to 100 mass parts of components (A). If it is this range, the adhesive composition of this invention may have the outstanding durability. The blending amount is more preferably 0.07 to 4 parts by mass, and still more preferably 0.1 to 3 parts by mass.

(E) Imidazole Compound In addition to the above components (A) to (C) and, if necessary, the above component (D), the pressure-sensitive adhesive composition of the present invention is also an imidazole compound (hereinafter simply referred to as “component (E)”). May be included. The imidazole compound is considered to play a role of a crosslinking (curing) accelerator for the carbodiimide crosslinking agent (C), and the pressure-sensitive adhesive composition of the present invention using both the carbodiimide crosslinking agent (C) and the imidazole compound (E) is Achieves practical adhesive properties in a short aging time, and is excellent in productivity.

  The imidazole compound used in the present invention is not particularly limited, but may be represented by the following chemical formula 1.

In Formula 1, R ¹ , R ² , and R ³ are each independently a hydrogen atom, a halogen atom, or a substituted or unsubstituted linear or branched chain having 1 to 10 carbon atoms. It is an alkyl group.

  As an example of the said halogen atom, a fluorine atom, a chlorine atom, a bromine atom, or an iodine atom is mentioned, for example.

  Examples of the linear or branched alkyl group having 1 to 10 carbon atoms include, for example, methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group, sec-butyl group, tert-butyl group, n-pentyl group, iso-amyl group, tert-pentyl group, neopentyl group, n-hexyl group, 3-methylpentan-2-yl group, 3-methylpentan-3-yl group, 4 -Methylpentyl group, 4-methylpentan-2-yl group, 1,3-dimethylbutyl group, 3,3-dimethylbutyl group, 3,3-dimethylbutan-2-yl group, n-heptyl group, 1- Methylhexyl group, 3-methylhexyl group, 4-methylhexyl group, 5-methylhexyl group, 1-ethylpentyl group, 1- (n-propyl) butyl group, 1,1-dimethylpentyl group, 1 4-dimethylpentyl group, 1,1-diethylpropyl group, 1,3,3-trimethylbutyl group, 1-ethyl-2,2-dimethylpropyl group, n-octyl group, 2-ethylhexyl group, 2-methylhexane -2-yl group, 2,4-dimethylpentan-3-yl group, 1,1-dimethylpentan-1-yl group, 2,2-dimethylhexane-3-yl group, 2,3-dimethylhexane-2 -Yl group, 2,5-dimethylhexane-2-yl group, 2,5-dimethylhexane-3-yl group, 3,4-dimethylhexane-3-yl group, 3,5-dimethylhexane-3-yl Group, 1-methylheptyl group, 2-methylheptyl group, 5-methylheptyl group, 2-methylheptan-2-yl group, 3-methylheptan-3-yl group, 4-methylheptan-3-yl group, 4- Tylheptan-4-yl group, 1-ethylhexyl group, 2-ethylhexyl group, 1-propylpentyl group, 2-propylpentyl group, 1,1-dimethylhexyl group, 1,4-dimethylhexyl group, 1,5-dimethyl Hexyl group, 1-ethyl-1-methylpentyl group, 1-ethyl-4-methylpentyl group, 1,1,4-trimethylpentyl group, 2,4,4-trimethylpentyl group, 1-isopropyl-1,2 -Dimethylpropyl group, 1,1,3,3-tetramethylbutyl group, n-nonyl group, 1-methyloctyl group, 6-methyloctyl group, 1-ethylheptyl group, 1- (n-butyl) pentyl group 4-methyl-1- (n-propyl) pentyl group, 1,5,5-trimethylhexyl group, 1,1,5-trimethylhexyl group, 2-methyloctane-3 -Yl group, n-decyl group, 1-methylnonyl group, 1-ethyloctyl group, 1- (n-butyl) hexyl group, 1,1-dimethyloctyl group, 3,7-dimethyloctyl group and the like.

  The alkyl group may be substituted with another substituent. Examples of substituents include, for example, halogen atoms such as fluorine atom, chlorine atom, bromine atom and iodine atom; alkyl groups such as methyl group, ethyl group, tert-butyl group and dodecyl group; phenyl group and p-tolyl group , Xylyl group, cumenyl group, naphthyl group, anthryl group, phenanthryl group and other aryl groups; methoxy group, ethoxy group, tert-butoxy group and other alkoxy groups; phenoxy group, p-tolyloxy group and other aryloxy groups; Groups, butoxycarbonyl groups, octyloxycarbonyl groups, phenoxycarbonyl, etc .; alkoxycarbonyl groups; acetoxy groups, propionyloxy groups, methacryloyloxy groups, benzoyloxy groups, etc .; acetyl groups, benzoyl groups, isobutyryl groups, acryloyl groups Acyl groups such as methacryloyl group and methoxalyl group; alkylamino groups such as methylamino group and cyclohexylamino group; dialkylamino groups such as dimethylamino group, diethylamino group, morpholino group and piperidino group; phenylamino group, p-tolylamino group and the like In addition to the arylamino group, hydroxy group, carboxy group, formyl group, amino group, nitro group, cyano group, trifluoromethyl group, trichloromethyl group and the like can be mentioned.

  Furthermore, specific examples of the imidazole compound include, for example, imidazole, 1-methylimidazole, 2-methylimidazole, 4-methylimidazole, 1-ethylimidazole, 2-ethylimidazole, 4-ethylimidazole, 1-propylimidazole. 2-propylimidazole, 4-propylimidazole, 1-butylimidazole, 2-butylimidazole, 4-butylimidazole, 1-pentylimidazole, 2-pentylimidazole, 4-pentylimidazole, 1-hexylimidazole, 2-hexylimidazole 4-hexylimidazole, 1-heptylimidazole, 2-heptylimidazole, 4-heptylimidazole, 1-octylimidazole, 2-octylimidazole, 4-octylimid Sol, 1-nonylimidazole, 2-nonylimidazole, 4-nonylimidazole, 1-decylimidazole, 2-decylimidazole, 4-decylimidazole, 1,2-dimethylimidazole, 1,2-diethylimidazole, 1-ethyl- 2-methylimidazole, 2-ethyl-4-methylimidazole, 1,4-dimethylimidazole, 1,5-dimethylimidazole, 1,2,4-trimethylimidazole, 1,4-dimethyl-2-ethylimidazole, 2- Examples include fluoroimidazole, 4-fluoroimidazole, 2-bromoimidazole, 4-bromoimidazole, 2-iodoimidazole, and 4-iodoimidazole.

Among these imidazole compounds, a compound in which at least one of R ¹ , R ² , and R ^{3 is} a linear or branched alkyl group having 1 to 10 carbon atoms is preferable from the viewpoint of productivity and price. -Methylimidazole, 1-ethylimidazole, 1-propylimidazole, 1-butylimidazole, 1,2-dimethylimidazole, 2-ethyl-4-methylimidazole are more preferred.

  It is preferable that the compounding quantity of a component (E) is 0.005-0.2 mass part with respect to 100 mass parts of components (A). Within such a range, a sufficient curing accelerating effect can be achieved, aging can be accomplished in a short time after crosslinking, and a sufficient adhesive force can be achieved. The blending amount is more preferably 0.007 to 0.2 parts by mass, further preferably 0.01 to 0.2 parts by mass, and particularly preferably 0.01 to 0.15 parts by mass.

  The said component (E) may be used independently and may be used in combination of 2 or more type. Moreover, a commercial item may be used for the said component (E), and a synthetic item may be used.

  Moreover, the pressure-sensitive adhesive composition of the present invention may contain a silane coupling agent (hereinafter also simply referred to as “component (F)”) 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, 3-glycidoxypropylmethyldiethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropiyl Triethoxysilane, γ-methacryloxypropylmethyldimethoxysilane, 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-mercaptop Pills methyl dimethoxy silane, bis - (3- [triethoxysilyl] 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.

  Moreover, you may use a silane coupling agent oligomer as a component (F). In the silane coupling agent oligomer, at least one silane compound having at least an alkoxy group is condensed to form a —Si—O—Si— structure, and at least one alkoxy group is bonded to the silicon atom. It is a compound having an organic functional group in the molecule.

  Examples of the organic functional group include a vinyl group, an epoxy group, a styryl group, a (meth) acryloyl group, a methacryloxy group, an acryloxy group, an amino group, a ureido group, a chloropropyl group, a mercapto group, and a polysulfide group. Among these, an epoxy group, a mercapto group, and a (meth) acryloyl group are preferable, and an epoxy group and a mercapto group are particularly preferable in order to achieve both improvement in durability of the resulting pressure-sensitive adhesive layer and realization of low adhesiveness.

  As the silane coupling agent oligomer, a dimer having 2 silicon atoms in one molecule to about 100 silicon atoms in one molecule, that is, having an average polymerization degree of 2 to 100 can be used. . When the average degree of polymerization increases, the viscosity of the silane coupling agent oligomer increases, and it may become a paste or a solid, which makes handling difficult. Therefore, the average degree of polymerization is preferably 2 to 80, more preferably 3 to 50.

  The organic functional group contained in the silane coupling agent oligomer is usually bonded to a silicon atom via a suitable linking group. Examples of the linking group include alkylene groups such as methylene group, ethylene group, trimethylene group, hexamethylene group and decamethylene group, divalent hydrocarbon groups having an aromatic ring such as methylphenylethyl group, methoxymethyl group and methoxy group. Examples thereof include a divalent aliphatic group having an oxygen atom between them, such as an ethyl group and a methoxypropyl group. When the organic functional group is an epoxy group, the functional group may be formed between two adjacent carbon atoms constituting the ring.

  The silane coupling agent oligomer may be, for example, a co-oligomer obtained by partial cohydrolysis polycondensation of a silane compound represented by the following chemical formula 2 and tetraalkoxysilane.

In the chemical formula 2, R ⁴ and R ⁵ each independently represents an alkyl group or a phenyl group, X represents an organic group having a mercapto group, an epoxy group, or a (meth) acryloyloxy group, and Y represents Represents an alkyl group, an alkoxy group, a phenyl group, a phenoxy group, an aralkyl group or an aralkyloxy group.

In the above chemical formula, the alkyl group represented by R ⁴ and R ⁵ has, for example, 1 to 10 carbon atoms. In particular, compounds in which R ⁴ and R ⁵ are each independently a methyl group or an ethyl group are preferably used.

  Specific examples of the organic functional group represented by X include, for example, mercaptomethyl group, 3-mercaptopropyl group, 6-mercaptohexyl group, 10-mercaptodecyl group, 2- (4-mercaptomethylphenyl) ethyl group, Glycidoxymethyl group, 3-glycidoxypropyl group, 2- (3,4-epoxycyclohexyl) ethyl group, acryloyloxymethyl group, 3-acryloyloxypropyl group, methacryloyloxymethyl group, 3-methacryloyloxypropyl group Etc.

  The alkyl group and alkoxy group represented by Y preferably have 1 to 10 carbon atoms, and the aralkyl and aralkyloxy groups preferably have 7 to 10 carbon atoms.

  Specific examples of the functional group-containing silane compound represented by the chemical formula 2 include, for example, mercaptomethyltrimethoxysilane, 3-mercaptopropyltrimethoxysilane, 3-mercaptopropyltriethoxysilane, and 2- (4-mercaptomethylphenyl). ) Ethyltrimethoxysilane, 6-mercaptohexyltrimethoxysilane, 10-mercaptodecyltrimethoxysilane, 3-mercaptopropylmethyldimethoxysilane, 3-mercaptopropylmethyldiethoxysilane, glycidoxymethyltrimethoxysilane, 3-glycyl Sidoxypropyltrimethoxysilane, 2- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, acryloyloxymethyltrimethoxysilane, -Acryloyloxypropyltrimethoxysilane, 3-acryloyloxypropyltriethoxysilane, methacryloyloxymethyltrimethoxysilane, 3-methacryloyloxypropyltrimethoxysilane, 3-methacryloyloxypropyltriethoxysilane, 3-methacryloyloxypropyltributoxysilane , 3-acryloyloxypropylmethyldimethoxysilane, 3-methacryloyloxypropylmethyldimethoxysilane, 3-methacryloyloxypropylmethyldiethoxysilane, and the like.

  In the tetraalkoxysilane partially cohydrolyzed and polycondensed with the functional group-containing silane compound represented by the chemical formula 2, the four alkoxy groups bonded to the silicon atom preferably have 1 to 10 carbon atoms. The four alkoxy groups bonded to the silicon atom may all be the same, or different alkoxy groups may be bonded to the silicon atom. From the viewpoint of ease of production or availability, compounds in which the same alkoxy group is bonded to a silicon atom are preferred, and specific examples include tetramethoxysilane, tetraethoxysilane, tetrapropoxysilane, and tetrabutoxysilane. It is done.

In the case where a silane coupling agent oligomer is formed by partial cohydrolysis polycondensation of the functional group-containing silane compound represented by Chemical Formula 2 and tetraalkoxysilane, in Formula 2 above, -OR ⁴ bonded to a silicon atom and A silanol group formed by partial hydrolysis of an alkoxysilyl group or phenoxysilyl group of —OR ⁵ and a silanol group formed by partial hydrolysis of an alkoxysilyl group in tetraalkoxysilane are condensed. Thus, it becomes a silane coupling agent oligomer. Such an oligomer is preferable because the pressure-sensitive adhesive composition tends to be difficult to scatter in the pressure-sensitive adhesive coating and drying step.

  When the silane coupling agent oligomer that can be used in the present invention is shown by a combination of monomers, for example, the following can be mentioned.

  Mercaptomethyl trimethoxysilane-tetramethoxysilane co-oligomer, mercaptomethyltrimethoxysilane-tetraethoxysilane co-oligomer, mercaptomethyltriethoxysilane-tetramethoxysilane co-oligomer, mercaptomethyltriethoxysilane -Tetraethoxysilane co-oligomer etc. are mentioned.

  As a mercaptopropyl group-containing co-oligomer, 3-mercaptopropyltrimethoxysilane-tetramethoxysilane co-oligomer, 3-mercaptopropyltrimethoxysilane-tetraethoxysilane co-oligomer, 3-mercaptopropyl triethoxysilane-tetramethoxysilane co-oligomer , 3-mercaptopropyltriethoxysilane-tetraethoxysilane co-oligomer and the like.

  As glycidoxymethyl group-containing co-oligomers, glycidoxymethyltrimethoxysilane-tetramethoxysilane co-oligomer, glycidoxymethyltrimethoxysilane-tetraethoxysilane co-oligomer, glycidoxymethyltriethoxysilane-tetramethoxysilane Examples include co-oligomers and glycidoxymethyltriethoxysilane-tetraethoxysilane co-oligomers.

  Examples of co-oligomers containing glycidoxypropyl groups include 3-glycidoxypropyltrimethoxysilane-tetramethoxysilane co-oligomer, 3-glycidoxypropyltrimethoxysilane-tetraethoxysilane co-oligomer, 3-glycidoxypropyl tri-oligomer. Examples include ethoxysilane-tetramethoxysilane co-oligomer, 3-glycidoxypropyltriethoxysilane-tetraethoxysilane co-oligomer, and the like.

  As a co-oligomer containing methacryloyloxypropyl group, 3-acryloyloxypropyltrimethoxysilane-tetramethoxysilane co-oligomer, 3-acryloyloxypropyltrimethoxysilane-tetraethoxysilane co-oligomer, 3-acryloyloxypropyltriethoxysilane-tetra Methoxysilane co-oligomer, 3-acryloyloxypropyltriethoxysilane-tetraethoxysilane co-oligomer, 3-acryloyloxypropylmethyldimethoxysilane-tetramethoxysilane co-oligomer, 3-acryloyloxypropylmethyldimethoxysilane-tetraethoxysilane co-oligomer, 3-acryloyloxypropylmethyldiethoxysilane-tetramethoxysilane co-oligomer, 3-acryloyl Co-oligomers containing acryloyloxypropyl groups, such as yloxypropylmethyldiethoxysilane-tetraethoxysilane co-oligomer, 3-methacryloyloxypropyltrimethoxysilane-tetramethoxysilane co-oligomer, 3-methacryloyloxypropyltrimethoxysilane-tetra Ethoxysilane co-oligomer, 3-methacryloyloxypropyltriethoxysilane-tetramethoxysilane co-oligomer, 3-methacryloyloxypropyltriethoxysilane-tetraethoxysilane co-oligomer, 3-methacryloyloxypropylmethyldimethoxysilane-tetramethoxysilane co-oligomer, 3-methacryloyloxypropylmethyldimethoxysilane-tetraethoxysilane co-oligomer, 3-methacryl Acryloyloxy propyl methyl diethoxy silane - tetramethoxysilane co-oligomer, 3-methacryloyloxypropyl diethoxysilane - tetraethoxysilane co-oligomer, and the like.

  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, KBE-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.); X-41-1805 which is a silane coupling agent oligomer having a mercapto group, a methoxy group and an ethoxy group, a mercapto group, a methyl group and methoxy X-41-1810 which is a silane coupling agent oligomer having a group, X-41-1053 which is a silane coupling agent oligomer having an epoxy group, a methoxy group and an ethoxy group, a silicone having an epoxy group, a methyl group and a methoxy group X-41-1058 which is a silane coupling agent (All trade names, both Shin-Etsu Chemical Co., Ltd.) can be mentioned.

  Among these silane coupling agents, KBM-303, KBM-403, KBE-402, KBE-403, KBM-5103, KBM-573, KBM-802, KBM-803, KBE-846, KBE-9007, X- 41-1805 and X-41-1810 are preferable, and KBM-403 and X-41-1810 are more preferable. In addition, the said silane coupling agent may be used independently and may be used in combination of 2 or more type.

  In the present invention, the amount of the silane coupling agent used is not particularly limited. Specifically, the amount used when the silane coupling agent (F) is used is preferably 0.03 to 1 part by mass, more preferably 0.05 to 100 parts by mass with respect to 100 parts by mass of the component (A). 0.5 parts by mass, more preferably 0.1 to 0.3 parts by mass. If it exists in this range, the outstanding heat resistance and adhesiveness can be exhibited.

  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 Chemicals, Inc.) 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 BASF Japan Ltd.) 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, at a temperature of 20 to 40 ° C., if necessary, and stirring with a stirrer or the like until it becomes uniform, for example, for 5 minutes to 5 hours.

  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 film thickness of the pressure-sensitive adhesive layer formed from the composition, the viscosity immediately after blending at 25 ° C. (after mixing each component for a predetermined time) (Within 10 minutes) is preferably 300 to 7000 mPa · s. For example, when used as an adhesive for an optical member, the viscosity immediately after blending at 25 ° C. (within 10 minutes after mixing each component for a predetermined time) is more preferably 2000 to 6000 mPa · s, and further preferably 2500 to 5000 mPa · s. s. For example, when used as a pressure-sensitive adhesive for a surface protective film, the viscosity immediately after blending at 25 ° C. (within 10 minutes after mixing each component for a predetermined time) is preferably 350 to 5000 mPa · s, more preferably 400 to 4000 mPa · s. It is. For example, when used as a pressure-sensitive adhesive for pressure-sensitive adhesive sheets, the viscosity immediately after blending at 25 ° C. (within 10 minutes after mixing each component for a predetermined time) is preferably 350 to 6800 mPa · s, more preferably 400 to 6500 mPa · s. is there. In addition, in this specification, the value measured by the method as described in the below-mentioned Example shall be employ | adopted for a viscosity.

  The pressure-sensitive adhesive composition of the present invention has an excellent pot life because an excessive increase in viscosity and gelation of the pressure-sensitive adhesive composition after preparation of the composition are suppressed.

  The pot life can be evaluated by comparing the viscosity of the composition immediately after preparing the pressure-sensitive adhesive composition with the viscosity of the composition after 12 hours from the preparation. That is, the composition after 12 hours from the preparation is preferably not gelled, and the viscosity of the composition after 12 hours from the preparation is the viscosity of the composition immediately after preparing the adhesive composition. More preferably, the increase is within 50%. If it is such a range, it will become an adhesive composition which has the outstanding workability | operativity.

  In this specification, “immediately after” “immediately after preparing the pressure-sensitive adhesive composition” in defining the viscosity means within 10 minutes. That is, the “viscosity of the composition immediately after preparing the pressure-sensitive adhesive composition” means the viscosity measured within 10 minutes after the preparation of the pressure-sensitive adhesive composition is completed (each component is mixed for a predetermined time).

  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. is there. The crosslinking of the pressure-sensitive adhesive composition is usually carried out under conditions of a temperature of 70 to 140 ° C. and preferably for 1 to 5 minutes.

  The pressure-sensitive adhesive layer formed from the pressure-sensitive adhesive composition of the present invention reaches practical pressure-sensitive adhesive performance in a short period of time immediately after crosslinking (pressure-sensitive adhesive processing) (no aging step). The pressure-sensitive adhesive performance of the pressure-sensitive adhesive layer is determined by the gel fraction of the pressure-sensitive adhesive layer immediately after crosslinking (adhesion processing) and after standing for 7 days in an atmosphere of 23 ° C. and 50% RH after the crosslinking (adhesion processing). It can evaluate by comparing with the gel fraction of an adhesive layer. That is, the gel fraction after standing for 7 days is preferably a gel fraction immediately after crosslinking (adhesion processing) ± 15%, more preferably a gel fraction immediately after crosslinking (adhesion processing) ± 10%. More preferably, the gel fraction immediately after crosslinking (adhesion processing) is ± 5%, and it is particularly preferable that the gel fraction immediately after crosslinking (adhesion processing) is ± 3%. If it is such a range, it will become an adhesive composition in which productivity improved significantly. As the gel fraction, a value measured by the method described in Examples described later is adopted.

  In the present specification, “immediately after“ crosslinking (adhesion processing) ”in defining the gel fraction means within 10 minutes. That is, “the gel fraction of the pressure-sensitive adhesive layer immediately after crosslinking (adhesion processing)” is the gel fraction measured within 10 minutes after the adhesion processing (drying (crosslinking) of the adhesive layer for a predetermined time at a predetermined temperature). Means. Similarly, “immediately after the production of the polarizing plate having the pressure-sensitive adhesive layer” is after pressure-sensitive adhesive processing (the pressure-sensitive adhesive composition solution layer is dried (crosslinked) for a predetermined time at a predetermined temperature to form a pressure-sensitive adhesive layer). It means within 10 minutes, meaning that a measurement sample is produced within the time.

  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, a surface protection film, and an adhesive sheet provided with the adhesive layer formed from the adhesive composition of this invention.

  Hereinafter, although these uses are demonstrated in detail, the use of the adhesive composition of this invention is not limited to these uses at all.

<Optical member>
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. That is, this invention provides an optical member provided with the adhesive layer formed from the adhesive composition of this invention.

  Preferred examples of the optical member of the present invention 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.

  When using the adhesive composition of this invention for the adhesive layer of an optical member, the component (A) contained in a composition is 0-9 mass parts carboxyl group containing monomer (a-1), 0-1.8. It contains a monomer component consisting of a hydroxy group-containing (meth) acrylic monomer (a-2) by mass part and 99.9-89.2 mass parts (meth) acrylic acid ester monomer (a-3). The weight average molecular weight is preferably 1 million to 2 million.

  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, the (meth) acrylic copolymer (A) always contains at least one of the structural unit derived from the component (a-1) and the structural unit derived from the component (a-2). means. And the total amount of a component (a-1), a component (a-2), and a component (a-3) shall be 100 mass parts.

  The amount of the component (a-1) in the component (A) used in the optical member application is 0 part by mass (that is, the component (a-1) is not included) or the component (a-1) is included. Is more preferably 0.1 to 9 parts by mass, and still more preferably 0.2 to 9 parts by mass. Moreover, the usage-amount of the component (a-2) in the component (A) in an optical member use is 0 mass part (namely, (a-2) component is not included), or (a-2) component is used. When it contains, it is more preferable that it is 0.05-1.8 mass part, and it is still more preferable that it is 0.1-1.8 mass part. Furthermore, it is more preferable that the usage-amount of the component (a-3) in the component (A) in an optical member use is 99.9-90 mass parts, and it is still more preferable that it is 99.9-91 mass parts. preferable.

  The total amount of the component (a-1) and component (a-2) used in the component (A) in the optical member application is preferably 0.05 to 10 parts by mass, More preferably, it is -9 mass parts.

  As for the weight average molecular weight of the component (A) in an optical member use, it is more preferable that it is 1,000,000-1,800,000, and it is further more preferable that it is 1.1 million-1,700,000.

  Moreover, it is preferable that content of the component (B) in the adhesive composition for optical member uses is 0.15-0.9 mass part with respect to 100 mass parts of component (A), 0.2 More preferably, it is -0.8 mass part. Moreover, it is preferable that it is 0.05-4 mass parts with respect to 100 mass parts of components (A), and, as for content of a component (C), it is more preferable that it is 0.05-3 mass parts. Within such a range, as an adhesive composition for optical members, as an adhesive composition for optical members, it has a long pot life and excellent workability, and reaches practical adhesive performance immediately after the adhesive processing (crosslinking) treatment. , Productivity is greatly improved.

  In addition, when the isocyanate crosslinking agent is used as the component (D), the amount of the component (D) used is preferably 0.07 to 3 parts by mass with respect to 100 parts by mass of the component (A). It is more preferable that it is 1-2 mass parts.

  When the imidazole compound is used as the component (E), the amount of the component (E) used is preferably 0.007 to 0.18 parts by mass with respect to 100 parts by mass of the component (A). More preferably, it is -0.1 mass part.

  Furthermore, in this use, it is preferable that a silane coupling agent (F) is included in the composition. Since the preferable specific example of the silane coupling agent (F), the preferable range of the amount used, and the like are the same as described above, the description thereof is omitted here.

  The application of the pressure-sensitive adhesive composition for optical members is not particularly limited, and examples thereof include a natural coater, a knife belt coater, a floating knife, a knife over roll, a knife on blanket, a spray, a dip, a kiss roll, a squeeze roll, a reverse roll, Various coating methods using apparatuses such as 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, although the application thickness (thickness after drying) of the pressure-sensitive adhesive composition when used for an optical member may be selected according to the substrate used and the application, it is preferably 5 to 35 μm, more Preferably it is 15-30 micrometers.

  When the pressure-sensitive adhesive composition of the present invention is used for an optical member, the gel fraction of the pressure-sensitive adhesive layer in an atmosphere of 23 ° C. and 50% RH immediately after crosslinking (adhesion processing) is 50 to 95%. Preferably, it is 60 to 92%, more preferably 70 to 90%. If it is such a range, a punching process and a slit process can be rapidly performed as an optical member provided with the adhesive layer. In order to set the gel fraction as described above, the conditions may be appropriately selected, such as adjusting the monomer composition of component (A), the amount of component (B), and the amount of component (C) added to the above ranges.

  In the optical member of the present invention, the adhesive strength of the pressure-sensitive adhesive layer formed on the optical member is preferably about 0.5 to 9 (N / 25 mm), more preferably about 1 to 6 (N / 25 mm). An adhesive strength in such a range can be advantageous for reworkability. In the present specification, the “adhesive strength” is determined by measuring according to the adhesive tape / adhesive sheet test method of JIS Z0237 (2000), and more specifically described in the following examples. Measured according to method.

  The pressure-sensitive adhesive composition of the present invention used for optical members has a long pot life and excellent workability, exhibits practical pressure-sensitive adhesive performance (especially an appropriate gel fraction) immediately after crosslinking (adhesive processing), and has a great productivity. To improve. Furthermore, the pressure-sensitive adhesive layer obtained from the pressure-sensitive adhesive composition of the present invention used for an optical member has an appropriate adhesive strength and adhesion to a substrate for an optical member, and further, metal corrosion inhibition / prevention Excellent light leakage resistance, durability, adherend contamination resistance, low temperature stability, and reworkability.

<Surface protection film>
The pressure-sensitive adhesive composition of the present invention can also be suitably used for a surface protective film, particularly a surface protective film for an optical member. That is, this invention provides a surface protection film provided with the adhesive layer formed from the adhesive composition of this invention.

  It does not restrict | limit especially as a protective film, A well-known protective film can be used similarly. For example, polyethylene terephthalate (PET), polyethylene, polypropylene, ethylene-vinyl acetate copolymer, polyester, polyvinyl chloride, polycarbonate, polyamide, polystyrene, or a resin film such as a composite film can be used. In particular, polyethylene terephthalate is preferable. Moreover, what has a thickness of about 15-50 micrometers can be used for a protective film, for example.

  In addition, the pressure-sensitive adhesive layer can be formed on the protective film by directly applying the pressure-sensitive adhesive composition of the present invention to the protective film, or by temporarily applying the pressure-sensitive adhesive composition of the present invention to another substrate (such as a release liner). It can be carried out by a method of transferring the coating formed.

  The surface protective film of this invention can be used for the use which protects the optical member bonded together by flat display panels, such as a liquid crystal display panel and a plasma display panel. Examples of the optical member include a polarizing plate, a retardation plate, a brightness enhancement plate, or an antiglare sheet. The optical member is a laminate of two or more optical materials such as a laminate of a polarizing plate and a retardation plate, a laminate of retardation plates, a laminate of a polarizing plate and a brightness enhancement plate or an antiglare sheet. May be. The surface protective film of the present invention can be used not only when the optical member is distributed alone but also when the optical member is distributed in a state of being bonded to the flat display panel.

  When using the adhesive composition of this invention for the adhesive layer of a surface protection film, the component (A) contained in a composition is 0-0.5 mass part carboxyl group containing monomer (a-1), 0. A monomer component comprising 6 to 9 parts by mass of a hydroxy group-containing (meth) acrylic monomer (a-2) and 99.4 to 90.5 parts by mass of a (meth) acrylic acid ester monomer (a-3) The weight average molecular weight is preferably 100,000 to 1,000,000. The total amount of component (a-1), component (a-2) and component (a-3) is 100 parts by mass.

  The usage-amount of the component (a-1) in the component (A) in a surface protection film use is 0 mass part (namely, (a-1) component is not included), or (a-1) component is included. In some cases, the amount is more preferably 0.1 to 0.5 parts by mass. Moreover, as for the usage-amount of the component (a-2) in the component (A) in a surface protection film use, it is more preferable that it is 0.7-9 mass parts, and it is further more preferable that it is 1-9 mass parts. Furthermore, as for the usage-amount of the component (a-3) in the component (A) in a surface protection film use, it is more preferable that it is 99.3-90.6 mass parts.

  The total amount of the component (a-1) and the component (a-2) used in the component (A) in the surface protective film application is more preferably 0.7 to 9.4 parts by mass. It is still more preferable that it is 0.8-9.3 mass parts.

  The weight average molecular weight of the component (A) in the surface protective film application is more preferably 150,000 to 900,000, and further preferably 200,000 to 850,000.

  Moreover, it is preferable that content of the component (B) in the adhesive composition for surface protection films is 0.15-0.9 mass part with respect to 100 mass parts of component (A). It is more preferable that it is 2-0.8 mass part. Moreover, it is preferable that content of a component (C) is 0.1-5 mass parts with respect to 100 mass parts of components (A). If it is such a range, as an adhesive composition for surface protection films, a pot life is long and it is excellent in workability | operativity, reaches practical adhesive performance immediately after bridge | crosslinking (adhesion processing), and productivity improves significantly.

  In addition, when the isocyanate crosslinking agent is used as the component (D), the amount of the component (D) used is more preferably 0.07 to 3 parts by mass with respect to 100 parts by mass of the component (A). More preferably, it is 1 to 2.5 parts by mass.

  When the imidazole compound is used as the component (E), the amount of the component (E) used is preferably 0.007 to 0.18 parts by mass with respect to 100 parts by mass of the component (A). More preferably, it is -0.1 mass part.

  In this application, the silane coupling agent (E) is preferably not included in the pressure-sensitive adhesive composition.

  The application method of the pressure-sensitive adhesive composition for use in the surface protective film is not particularly limited, and a conventionally known method is used. Specifically, natural coater, knife belt coater, floating knife, roll coat, air knife coat, knife over roll, knife on blanket, spray, dip, kiss roll, squeeze roll, reverse roll, air blade, curtain flow coater, doctor Various coating methods using apparatuses such as a blade, a wire bar, a die coater, a comma coater, a baker applicator, and a gravure coater may be mentioned. Of these, roll coating, gravure coating, reverse coating, roll brushing, spray coating, air knife coating, and die coating are preferably used. Moreover, the application | coating thickness (thickness after drying) of the composition formed on a protective film is not restrict | limited in particular, It can select suitably by a desired use. Preferably, the coating thickness of the composition formed on the protective film (the thickness of the pressure-sensitive adhesive layer; the thickness after drying) is 3 to 200 μm, more preferably 10 to 100 μm, and even more preferably 15 to 50 μm. Degree.

  When the pressure-sensitive adhesive composition of the present invention is used for a surface protective film, the gel fraction of the pressure-sensitive adhesive layer in an atmosphere of 23 ° C. and 50% RH immediately after crosslinking (adhesion processing) is 70 to 100%. Is more preferable, 80 to 99% is more preferable, and 85 to 98% is more preferable. If it is such a range, a punching process and a slit process can be rapidly performed as a surface protection film provided with the adhesive layer. In order to set the gel fraction as described above, the conditions may be appropriately selected, such as adjusting the monomer composition of component (A), the amount of component (B), and the amount of component (C) added to the above ranges.

  In the surface protective film of the present invention, the adhesive strength of the pressure-sensitive adhesive layer formed on the surface protective film is preferably about 0.05 to 0.30 (N / 25 mm), and 0.09 to 0.20 (N / 25 mm). ) Degree is more preferable. An adhesive strength in such a range may be advantageous for adherend contamination.

  The pressure-sensitive adhesive composition of the present invention used for a surface protective film has a long pot life and excellent workability, exhibits practical pressure-sensitive adhesive performance (particularly an appropriate gel fraction) immediately after crosslinking (adhesive processing), and has a high productivity. Greatly improved. Furthermore, the pressure-sensitive adhesive layer obtained from the pressure-sensitive adhesive composition has an appropriate pressure-sensitive adhesive force and adhesion to a substrate, suppresses and prevents metal corrosion, adherend resistance, low temperature stability, and transparency. It also suppresses and prevents foaming under high temperature and high pressure conditions (during autoclaving).

<Adhesive sheet>
The pressure-sensitive adhesive composition of the present invention can be formed into a pressure-sensitive adhesive sheet such as a sheet or a tape by coating on a base material or a separator and applying a drying (crosslinking) treatment to form a pressure-sensitive adhesive layer. it can. That is, this invention provides an adhesive sheet provided with the adhesive layer formed from the adhesive composition of this invention.

  As the base material of the adhesive sheet, polyester films such as polyethylene terephthalate film (PET film), plastic films such as polypropylene film and cellophane film, plastics such as polyurethane and ethylene-propylene terpolymer (EPT), foams of rubber, Various known thin leaf members such as paper and aluminum foil are used. Depending on the material, the surface of these base materials may be subjected to a ground treatment such as corona treatment, plasma treatment, or easy adhesion layer formation, or formation of an antistatic layer. For the separator, the surface of the same plastic film as the above-mentioned base material is subjected to a release treatment such as a silicone-based, fluorine-based, or long-chain alkyl-based release treatment agent, or a polypropylene film not subjected to such a release treatment. Various types can be used.

  When the pressure-sensitive adhesive layer is formed on the substrate, it may be provided on one side to be a single-sided pressure-sensitive adhesive sheet, or may be provided on both sides to be a double-sided pressure-sensitive adhesive sheet. When providing on both surfaces, it can also be set as the tape from which an adhesive kind differs on both surfaces using the adhesive composition of this invention only on one surface. When forming an adhesive layer on a separator, it can be used as a double-sided adhesive sheet.

  When using the adhesive composition of this invention for the adhesive layer of an adhesive sheet, the component (A) contained in a composition is 0-9 mass parts carboxyl group containing monomer (a-1), 0-9 mass parts. It preferably contains a monomer component consisting of a hydroxy group-containing (meth) acrylic monomer (a-2) and 99.9 to 82 parts by mass of a (meth) acrylic acid ester monomer (a-3). The molecular weight is preferably 100,000 to 1,000,000.

  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, the (meth) acrylic copolymer (A) always contains at least one of the structural unit derived from the component (a-1) and the structural unit derived from the component (a-2). means. And the total amount of a component (a-1), a component (a-2), and a component (a-3) shall be 100 mass parts.

  The usage-amount of the component (a-1) in the component (A) in an adhesive sheet use is 0 mass part (namely, it does not contain the (a-1) component), or when the (a-1) component is included. Is more preferably 0.1 to 8 parts by mass, and still more preferably 0.15 to 7.5 parts by mass. Moreover, the usage-amount of the component (a-2) in the component (A) in an adhesive sheet use is 0 mass part (namely, (a-2) component is not included), or (a-2) component is used. When included, it is preferably 0.1 to 9 parts by mass. Furthermore, as for the usage-amount of the component (a-3) in the component (A) in an adhesive sheet use, it is more preferable that it is 99.3-90.6 mass parts.

  The total amount of the component (a-1) and the component (a-2) used in the component (A) in the pressure-sensitive adhesive sheet is more preferably 0.7 to 9.4 parts by mass, It is still more preferable that it is 0.8-9.3 mass parts.

  As for the weight average molecular weight of the component (A) in an adhesive sheet use, it is more preferable that it is 150,000-950,000, and it is further more preferable that it is 200,000-900,000.

  Moreover, it is preferable that content of the component (B) in the adhesive composition for adhesive sheets is 0.15-0.9 mass part with respect to 100 mass parts of component (A), 0.2 More preferably, it is -0.8 mass part. Moreover, it is preferable that it is 0.06-4 mass parts with respect to 100 mass parts of components (A), and, as for content of a component (C), it is preferable that it is 0.1-3 mass parts. If it is such a range, as an adhesive composition for surface protection films, a pot life is long and it is excellent in workability | operativity, reaches practical adhesive performance immediately after a crosslinking process, and productivity improves significantly.

  In addition, when the isocyanate crosslinking agent is used as the component (D), the amount of the component (D) used is more preferably 0.07 to 3 parts by mass with respect to 100 parts by mass of the component (A). More preferably, it is 1-2 mass parts.

  When the imidazole compound is used as the component (E), the amount of the component (E) used is preferably 0.007 to 0.18 parts by mass with respect to 100 parts by mass of the component (A). More preferably, it is -0.12 mass part.

  In this application, the silane coupling agent (E) is preferably not included in the pressure-sensitive adhesive composition.

  The application method of the pressure-sensitive adhesive composition for pressure-sensitive adhesive sheets is not particularly limited, and a conventionally known method is used. Specifically, natural coater, knife belt coater, floating knife, roll coat, air knife coat, knife over roll, knife on blanket, spray, dip, kiss roll, squeeze roll, reverse roll, air blade, curtain flow coater, doctor Various coating methods using apparatuses such as a blade, a wire bar, a die coater, a comma coater, a baker applicator, and a gravure coater may be mentioned. Of these, roll coating, gravure coating, reverse coating, roll brushing, spray coating, air knife coating, and die coating are preferably used. Moreover, the application thickness (thickness after drying) of the composition formed on the pressure-sensitive adhesive sheet is not particularly limited, and can be appropriately selected depending on a desired application. Preferably, the coating thickness of the composition formed on the pressure-sensitive adhesive sheet (thickness of the pressure-sensitive adhesive layer; thickness after drying) is about 3 to 200 μm, more preferably about 5 to 100 μm.

  When the pressure-sensitive adhesive composition of the present invention is used for a pressure-sensitive adhesive sheet, the gel fraction of the pressure-sensitive adhesive layer in an atmosphere of 23 ° C. and 50% RH immediately after crosslinking (adhesion processing) is 70 to 100%. Preferably, it is 80 to 99%, more preferably 85 to 98%. If it is such a range, a punching process and a slit process can be rapidly performed as an adhesive sheet provided with the adhesive layer. In order to set the gel fraction as described above, the conditions may be appropriately selected, such as adjusting the monomer composition of component (A), the amount of component (B), and the amount of component (C) added to the above ranges.

  In the pressure-sensitive adhesive sheet of the present invention, the pressure-sensitive adhesive force of the pressure-sensitive adhesive layer formed on the pressure-sensitive adhesive sheet is preferably about 0.05 to 20 (N / 25 mm), and more preferably about 0.1 to 15 (N / 25 mm). If it is the adhesive force of such a range, it can respond to adhesive sheets, such as a sheet form and a tape form which require various adhesive forces.

  The pressure-sensitive adhesive composition of the present invention used for a pressure-sensitive adhesive sheet has a long pot life and excellent workability, exhibits practical pressure-sensitive adhesive performance (particularly an appropriate gel fraction) immediately after crosslinking (adhesive processing), and greatly improves productivity. To improve. Furthermore, the pressure-sensitive adhesive layer obtained from the pressure-sensitive adhesive composition has an appropriate pressure-sensitive adhesive force and adhesion to a substrate, suppresses and prevents metal corrosion, adherend resistance, low temperature stability, and transparency. Excellent in heat resistance and moist heat resistance.

  The present invention will be described in further detail 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, the viscosity of the pressure-sensitive adhesive composition, and the weight average molecular weight of the polymer (A) were measured by the following methods.

<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 Y is the total mass Z of the glass plate and the remaining solid content.

<Viscosity>
The polymer solution or pressure-sensitive adhesive composition placed in a glass bottle was temperature-controlled at 25 ° C. and measured with a B-type viscometer. The viscosity of the pressure-sensitive adhesive composition was measured twice immediately after the pressure-sensitive adhesive composition was prepared and 12 hours after the preparation.

<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 19)
By performing the same operation as in Synthesis Example 1 except that the composition of the monomer component in Synthesis Example 1 was changed to the composition shown in Table 2 below, the polymer (A-2) A solution of (A-19) was obtained. Moreover, the solid content and viscosity of the obtained polymer (A-2)-(A-19) solution, and the weight average molecular weight of polymer (A-2)-(A-19) were measured. The results are shown in Table 2 below. In Table 2 below, “BA” is butyl acrylate; “MA” is methyl acrylate; “HEA” is 2-hydroxyethyl acrylate; “4HBA” is 4-hydroxybutyl acrylate. “HEAA” is N-2-hydroxyethylacrylamide; “AA” is acrylic acid.

Example 1
500 parts by mass of the polymer (A-1) solution obtained in Synthesis Example 1 as the polymer (A) (100 parts by mass as the solid content of the polymer) and the peroxide as the peroxide crosslinking agent (B). Benzoyl oxide (Sigma Aldrich Japan Co., Ltd., sample name B-1) 0.2 parts by mass, Carbodilite (registered trademark) V-01 (Nisshinbo Chemical Co., Ltd., sample name C-1) which is a carbodiimide crosslinking agent (C) ) 1 part by mass, Coronate (registered trademark) L (trimethylolpropane / tolylene diisocyanate trimer adduct, Nippon Polyurethane Industry Co., Ltd., sample name D-1) which is an isocyanate crosslinking agent (D) 0.1 mass Part, 1-methylimidazole (manufactured by Tokyo Chemical Industry Co., Ltd., sample name E-1) which is imidazole compound (E), and silane coupling agent (F) A Shin-Etsu Silicone X-41-1810 (manufactured by Shin-Etsu Chemical Co., Ltd., sample name F-1) 0.1 parts by mass is mixed at room temperature (25 ° C.) for 10 minutes, and a solution in which the pressure-sensitive adhesive composition is dissolved is obtained. Obtained.

  This solution is applied onto a peeled PET film (Mitsubishi Resin, MRF38, thickness: 38 μm) so that the thickness after drying is 25 μm, and dried at 130 ° C. for 3 minutes to form an adhesive layer. After that, it was bonded to a polarizing plate to produce a polarizing plate with an adhesive layer.

(Examples 2 to 10, Comparative Examples 1 to 9)
Polymers synthesized in the above synthesis examples at the composition ratios shown in Table 4 and Table 5, peroxide crosslinking agents, carbodiimide crosslinking agents, isocyanate crosslinking agents, imidazole compounds, silane coupling agents, and other crosslinking agents Except having used this, it carried out similarly to Example 1, and prepared the solution in which the adhesive composition is melt | dissolving, and preparation of the polarizing plate with an adhesive layer. Peroxide crosslinking agents B-1 and B-2, carbodiimide crosslinking agents C-1, C-2 and C-3, and imidazole compounds E-1, E-2, E-3 and E-4, silane The details of coupling agents F-1, F-2, F-3 and F-4, and other crosslinking agents G-1 are as shown in Table 3 below.

  About the polarizing plate with an adhesive layer of Examples 1-10 and Comparative Examples 1-9 obtained as mentioned above, each performance was evaluated according to the following method. The results are shown in Table 4 and Table 5 below.

1. Metal corrosion inhibition / prevention Immediately after preparation of a polarizing plate having an adhesive layer (in each case, the coating layer of the solution in which the adhesive composition is dissolved is dried (crosslinked) at 130 ° C. for 3 minutes to form an adhesive layer. (Within 10 minutes), a polarizing plate with a pressure-sensitive adhesive layer was prepared by bonding to a polarizing plate, and the pressure-sensitive adhesive layer surface was bonded to an aluminum foil, followed by 2 in an atmosphere of 60 ° C. and 90% RH. The samples were left for a day and the corrosivity at that time was observed. In Tables 4 and 5 below, “◯” represents no change, and “x” represents whitening.

2. Light leakage resistance Immediately after the production of a polarizing plate having a pressure-sensitive adhesive layer (after forming a pressure-sensitive adhesive layer by drying (crosslinking) the coating layer of the solution in which the pressure-sensitive adhesive composition is dissolved in each example at 130 ° C. for 3 minutes. Within 10 minutes), a polarizing plate with a pressure-sensitive adhesive layer is prepared by bonding to a polarizing plate, and this polarizing plate is 120 mm (polarizing plate MD direction) × 60 mm and 120 mm (polarizing plate TD direction) × 60 mm. After cutting and bonding each glass plate so as to overlap each other, autoclaving was performed 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 and Table 5 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 It represents that light leakage was observed, respectively.

3. Durability Immediately after the production of the polarizing plate having the pressure-sensitive adhesive layer (in each example, the coating layer of the solution in which the pressure-sensitive adhesive composition was dissolved was dried (crosslinked) at 130 ° C. for 3 minutes to form the pressure-sensitive adhesive layer. Within a minute), a polarizing plate with a pressure-sensitive adhesive layer was prepared by laminating the polarizing plate, this polarizing plate was cut into 120 mm (polarizing plate MD direction) × 60 mm, and bonded to a glass plate. The autoclave treatment was performed for 20 minutes at a temperature of 0.49 MPa (5 kg / cm ² ). Thereafter, the appearance after being allowed to stand for 120 hours in an atmosphere of 100 ° C. and in an atmosphere of 80 ° C. and 90% RH was observed. In Table 4 and Table 5 below, “◯” represents that foaming, floating, and peeling were not observed, and “X” represents that foaming, floating, and peeling were observed.

4). Adhesive strength Immediately after the production of a polarizing plate having an adhesive layer (in each example, the coating layer of the solution in which the adhesive composition was dissolved was dried (crosslinked) at 130 ° C. for 3 minutes to form an adhesive layer. Within a minute), a polarizing plate with a pressure-sensitive adhesive layer was prepared by bonding to a polarizing plate, this polarizing plate was cut to a width of 25 mm, and bonded to a glass plate at 50 ° C., 0.49 MPa (5 kg / cm ^2). ) Was autoclaved 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 and Table 5 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. The contact angle was measured according to the wettability test method for the substrate glass surface described in JIS R3257 (1999). In Tables 4 and 5 below, “◯” indicates a change in the contact angle of the glass plate surface before and after the adhesion measurement is 3 ° or less, and “X” indicates a change in the contact angle of the glass plate surface before and after the adhesion measurement. Each case is shown.

7). Low temperature stability Immediately after the production of the polarizing plate having the pressure-sensitive adhesive layer (after forming the pressure-sensitive adhesive layer by drying (crosslinking) the coating layer of the solution in which the pressure-sensitive adhesive composition is dissolved in each example at 130 ° C. for 3 minutes. Within 10 minutes), the polarizing plate was laminated to produce a polarizing plate with an adhesive layer, this polarizing plate was cut into 120 mm (polarizing plate MD direction) × 60 mm, and bonded to a glass plate. The autoclave treatment was performed for 20 minutes under the conditions of 0 ° C. and 0.49 MPa (5 kg / cm ² ). Then, the external appearance after leaving for 120 hours in -40 degreeC atmosphere was observed. In Table 4 and Table 5 below, “◯” indicates that foaming, floating, peeling, and recrystallized materials were not observed, and “×” indicates that foaming, floating, peeling, and recrystallized materials were observed, respectively. To express.

8). Reworkability 4. The peeled state was observed when measuring the adhesive strength. In Tables 4 and 5 below, “◯” indicates that interfacial fracture was observed, and “×” indicates that the adhesive was transferred and / or cohesive fracture was observed on the glass plate (adhered body). Represent each.

9. Gel fraction In place of the polarizing plate having the pressure-sensitive adhesive layer prepared in Examples 1 to 10 and Comparative Examples 1 to 9, a peeled polyester film was used, and the solution in which the pressure-sensitive adhesive composition was dissolved was used. After coating on the peeled polyester film so that the thickness after drying is 25 μm, this coating layer is dried (crosslinked) at 130 ° C. for 3 minutes, and the pressure-sensitive adhesive layer is formed on the peeled polyester film. The gel fraction is measured within 10 minutes (immediately after production of a peeled polyester film having an adhesive layer) and after standing for 7 days in an atmosphere of 23 ° C. and 50% RH after the formation of the adhesive layer (adhesion processing). did. The gel fraction was determined by weighing about 0.1 g of the pressure-sensitive adhesive composition immediately after the production of the polarizing plate having the pressure-sensitive adhesive layer and after standing for 7 days in an atmosphere of 23 ° C. and 50% RH, and 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 and Table 5 below. In Table 4 and Table 5 below, the “immediately after blending” viscosity that defines the viscosity of the pressure-sensitive adhesive composition is within 10 minutes after the preparation of the pressure-sensitive adhesive composition is completed (each component is mixed for a predetermined time). Means the measured viscosity. Similarly, in the following Tables 4 and 5, “immediately after processing” that defines the gel fraction of the pressure-sensitive adhesive composition is the above-mentioned 9. The gel fraction measured about the sample immediately after preparation of the polyester film which carried out the peeling process which has an adhesive layer instead of the polarizing plate which has an adhesive layer in a gel fraction (within 10 minutes) is meant.

  Moreover, about the polarizing plate with an adhesive layer of the comparative example 3, said 9 .. In the measurement of the gel fraction, the above 9. except that it is left for 0.5 days in an atmosphere of 23 ° C. and 50% RH after the formation of the pressure-sensitive adhesive layer (adhesion processing). When the gel fraction was measured by measuring the gel fraction after standing for 0.5 days, the gel fraction was 63%.

  As apparent from Tables 4 and 5 above, the pressure-sensitive adhesive compositions of the present invention (Examples 1 to 10) are compared to the pressure-sensitive adhesive compositions (Comparative Examples 1 to 9) that are outside the scope of the present invention. The pot life is excellent, and the pressure-sensitive adhesive layer can be crosslinked (cured) in a very short period (within 10 minutes) after the crosslinking treatment. From this, it is considered that the pressure-sensitive adhesive composition of the present invention can greatly improve both workability and productivity. Moreover, as is clear from Table 4 and Table 5 above, the polarizing plates (Examples 1 to 10) using the pressure-sensitive adhesive composition of the present invention are pressure-sensitive adhesive compositions (Comparative Example 1) that are outside the scope of the present invention. As compared with the polarizing plate using ~ 9), it is excellent in light leakage resistance, durability, adhesion to a substrate, adherend contamination, low temperature stability and reworkability.

(Synthesis Example 20)
In a flask equipped with a reflux condenser and a stirrer, 40 parts by mass of n-butyl acrylate (manufactured by Nippon Shokubai Co., Ltd.), 59 parts by mass of 2-ethylhexyl acrylate, 1 part by mass of 2-hydroxyethyl acrylate, and 150 parts by mass of ethyl acetate Was introduced. Next, the temperature was raised to 65 ° C. while performing nitrogen substitution, 0.1 parts by mass of azobisisobutyronitrile (AIBN) was added, 0.05 parts by mass of AIBN was further added after 1 hour, and the temperature was maintained at 65 ° C. Polymerization was carried out for 6 hours. After completion of the polymerization reaction, 36 parts by mass of ethyl acetate was added for dilution, followed by cooling to room temperature to obtain a polymer (sample name: A-20) solution. The obtained polymer solution had a solid content of 35% and a viscosity of 3500 mPa · s. Moreover, the weight average molecular weight of the obtained polymer (A-20) was 800,000.

(Synthesis Examples 21 to 38)
A polymer (A-21) was obtained by performing the same operation as in Synthesis Example 20, except that the composition of the monomer component in Synthesis Example 20 was changed to the composition shown in Table 6 below. A solution of (A-38) was obtained. Moreover, the solid content and viscosity of the obtained polymer (A-20)-(A-38) solution, and the weight average molecular weight of polymer (A-20)-(A-38) were measured. The results are shown in Table 6 below. In Table 6 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; “AM” is acrylamide.

(Example 11)
286 parts by mass (100 parts by mass as the solid content of the polymer) of the polymer (A-20) solution obtained in Synthesis Example 20 which is the polymer (A), and the peroxide cross-linking agent (B). Benzoyl oxide (Sigma Aldrich Japan Co., Ltd., sample name B-1) 0.2 parts by mass, Carbodilite (registered trademark) V-01 (Nisshinbo Chemical Co., Ltd., sample name C-1) which is a carbodiimide crosslinking agent (C) ) 0.5 parts by mass, Duranate (trademark) 24A-100 (hexamethylene diisocyanate bullet type, manufactured by Asahi Kasei Chemicals Corporation, sample name D-2) which is an isocyanate crosslinking agent (D) 0.5 parts by mass, imidazole compound (E) 1-methylimidazole (manufactured by Tokyo Chemical Industry Co., Ltd., sample name E-1) 0.01 parts by mass was mixed at room temperature (25 ° C.) for 10 minutes, To obtain a solution composition is dissolved.

  This solution is applied onto a peeled PET film (Mitsubishi Resin, MRF38, thickness: 38 μm) so that the thickness after drying is 25 μm, and dried at 130 ° C. for 3 minutes to form an adhesive layer. Then, the surface protective film (1) was produced by further bonding the adhesive layer side to a PET film (trade name Lumirror (registered trademark) S10 # 25, thickness: 23 μm, manufactured by Toray Industries, Inc.).

(Examples 12-20, Comparative Examples 10-18)
Except for using the polymers synthesized in Synthesis Examples 21 to 38, carbodiimide crosslinking agents, imidazole compounds, isocyanate crosslinking agents, and other additives at the composition ratios shown in Table 8 and Table 9 below. In the same manner as in Example 11, a solution in which the pressure-sensitive adhesive composition was dissolved and a surface protective film were prepared, and the surface protective films (2) to (10) and the comparative surface protective films (1) to ( 9) was obtained. Peroxide crosslinking agents B-1 and B-2, carbodiimide crosslinking agents C-1 and C-3, isocyanate crosslinking agents D-2 and D-3, and imidazole compounds E-1, E-2, E- Details of 3 and E-4, and other additives H-1, H-2 and H-3 are as follows.

  About the surface protection film obtained by Examples 11-20 and Comparative Examples 10-18 obtained as mentioned above, each performance was evaluated according to the following method.

1. Metal corrosion inhibition / prevention Immediately after the preparation of the surface protective film having the pressure-sensitive adhesive layer (in each case, the coating layer of the solution in which the pressure-sensitive adhesive composition is dissolved is dried (crosslinked) at 130 ° C. for 3 minutes to form the pressure-sensitive adhesive layer. Within 10 minutes from the formation), the adhesive layer surface was bonded to an aluminum foil, and then allowed to stand in an atmosphere of 60 ° C. and 90% RH for 2 days, and the corrosivity at that time was observed. In Tables 8 and 9, “◯” indicates no change, and “x” indicates whitening.

2. Autoclave suitability Immediately after the preparation of the surface protective film having the pressure-sensitive adhesive layer (after forming the pressure-sensitive adhesive layer by drying (crosslinking) the coating layer of the solution in which the pressure-sensitive adhesive composition is dissolved in each example at 130 ° C. for 3 minutes. Within 10 minutes), the surface protective film is cut to a width of 25 mm, and this is bonded to the polarizing plate, and autoclaved for 20 minutes under the conditions of 50 ° C. and 0.49 MPa (5 kg / cm ² ). Foaming was observed. In Table 8 and Table 9 below, “◯” represents the case where foaming was not observed, and “x” represents the case where foaming was observed.

3. Immediately after the surface protective film having the pressure-sensitive adhesive layer is formed (after forming the pressure-sensitive adhesive layer by drying (crosslinking) the coating layer of the solution in which the pressure-sensitive adhesive composition is dissolved in each example at 130 ° C. for 3 minutes. Within 10 minutes), the surface protective film was cut to a width of 25 mm, and this was bonded to a polarizing plate, and autoclaved for 20 minutes under the conditions of 50 ° C. and 0.49 MPa (5 kg / cm ² ). Using a tensile tester in an atmosphere of 23 ° C. and 50% RH at a peeling angle of 180 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.

4). 2. Adhesiveness to substrate At the time of measuring the adhesive strength, the adhesion to the protective film (base material) was evaluated. In Table 8 and Table 9 below, “◯” represents that the adhesive was not peeled off from the substrate at all, and “X” represents that the adhesive was peeled off from the substrate.

5. Adherent contamination property 3. The contact angle of the polarizing plate surface before and after measuring the adhesive force was measured. The contact angle was measured according to the wettability test method for the substrate glass surface described in JIS R3257 (1999). In Table 8 and Table 9 below, “◯” indicates a change in the contact angle of the polarizing plate surface before and after the measurement of the adhesive strength is 3 ° or less, and “X” indicates a change in the contact angle of the polarizing plate surface before and after the measurement of the adhesive strength. Each case is shown.

6). Low temperature stability Immediately after preparation of the surface protective film having the pressure-sensitive adhesive layer (in each case, the coating layer of the solution in which the pressure-sensitive adhesive composition is dissolved is dried (crosslinked) at 130 ° C. for 3 minutes to form a pressure-sensitive adhesive layer. Within 10 minutes), the surface protective film was bonded to the polarizing plate, and autoclaved for 20 minutes under the conditions of 50 ° C. and 0.49 MPa (5 kg / cm ² ). Then, the external appearance after leaving for 120 hours in -40 degreeC atmosphere was observed. In Table 8 and Table 9 below, “◯” indicates that foaming, floating, peeling, and recrystallized materials were not observed, and “×” indicates that foaming, floating, peeling, and recrystallized materials were observed, respectively. To express.

7). Transparency of the pressure-sensitive adhesive layer Immediately after the preparation of the surface protective film having the pressure-sensitive adhesive layer (in each case, the coating layer of the solution in which the pressure-sensitive adhesive composition is dissolved is dried (crosslinked) at 130 ° C. for 3 minutes to form the pressure-sensitive adhesive layer. Within 10 minutes from the formation, the transparency of the pressure-sensitive adhesive layer of the surface protective film was visually confirmed. In Table 8 and Table 9 below, “◯” represents a case where transparency was good, and “x” represents a case where white turbidity was observed in the pressure-sensitive adhesive layer.

8). Gel fraction Instead of the PET film having the pressure-sensitive adhesive layer prepared in Examples 11 to 20 and Comparative Examples 10 to 18, a polyester film subjected to a release treatment was used, and a solution in which the pressure-sensitive adhesive composition was dissolved was used. After coating on the peeled polyester film so that the thickness after drying is 25 μm, this coating layer is dried (crosslinked) at 130 ° C. for 3 minutes, and the pressure-sensitive adhesive layer is formed on the peeled polyester film. The gel fraction is measured within 10 minutes (immediately after production of a peeled polyester film having an adhesive layer) and after standing for 7 days in an atmosphere of 23 ° C. and 50% RH after the formation of the adhesive layer (adhesion processing). did. The gel fraction was obtained by weighing about 0.1 g of the pressure-sensitive adhesive composition immediately after the production of the release-treated polyester film having the pressure-sensitive adhesive layer and after standing for 7 days in an atmosphere of 23 ° C. and 50% RH. 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 8 and Table 9 below. In Tables 8 and 9 below, the “immediately after blending” viscosity that defines the viscosity of the pressure-sensitive adhesive composition is within 10 minutes after the preparation of the pressure-sensitive adhesive composition is completed (each component is mixed for a predetermined time). Means the measured viscosity. Similarly, in the following Tables 8 and 9, “immediately after processing” that defines the gel fraction of the pressure-sensitive adhesive composition is the above-mentioned 9. It means the gel fraction measured for the sample immediately after the production of the peeled polyester film (within 10 minutes) having the pressure-sensitive adhesive layer in the gel fraction.

  As is clear from Table 8 and Table 9 above, the pressure-sensitive adhesive compositions (Examples 11 to 20) of the present invention are compared with the pressure-sensitive adhesive compositions (Comparative Examples 10 to 18) that are outside the scope of the present invention. The pot layer is excellent in pot life, and the pressure-sensitive adhesive layer can be crosslinked (cured) in a very short period (within 10 minutes) after the crosslinking treatment. From this, it is considered that the pressure-sensitive adhesive composition of the present invention can greatly improve both workability and productivity. Moreover, as is clear from Table 8 and Table 9 above, the surface protective films (Examples 11 to 20) using the pressure-sensitive adhesive composition of the present invention are pressure-sensitive adhesive compositions (comparative examples) that are outside the scope of the present invention. Compared with the comparative surface protective film using 10-18), it is excellent in adhesion to the substrate, adherend contamination, low temperature stability, transparency of the pressure-sensitive adhesive layer and autoclave suitability.

(Synthesis Example 39)
In a flask equipped with a reflux condenser and a stirrer, 40 parts by mass of n-butyl acrylate (manufactured by Nippon Shokubai Co., Ltd.), 59 parts by mass of 2-ethylhexyl acrylate, 1 part by mass of 2-hydroxyethyl acrylate, and 150 parts by mass of ethyl acetate Was introduced. Next, the temperature was raised to 65 ° C. while performing nitrogen substitution, 0.1 parts by mass of azobisisobutyronitrile (AIBN) was added, 0.05 parts by mass of AIBN was further added after 1 hour, and the temperature was maintained at 65 ° C. Polymerization was carried out for 6 hours. After completion of the polymerization reaction, 36 parts by mass of ethyl acetate was added for dilution, followed by cooling to room temperature to obtain a polymer (sample name: A-39) solution. The obtained polymer solution had a solid content of 35% and a viscosity of 3500 mPa · s. Moreover, the weight average molecular weight of the obtained polymer (A-39) was 800,000.

(Synthesis Examples 40 to 57)
In Synthesis Example 39, the polymer (A-40) was obtained by performing the same operation as in Synthesis Example 39 except that the composition of the monomer component was changed to the composition shown in Table 10 below. A solution of (A-57) was obtained. Moreover, the solid content and viscosity of the obtained polymer (A-39)-(A-57) solution, and the weight average molecular weight of polymer (A-39)-(A-57) were measured. The results are shown in Table 10 below. In Table 10 below, “BA” is butyl acrylate; “2EHA” is 2-ethylhexyl acrylate; “VAc” is vinyl acetate; “HEA” is 2-hydroxyethyl acrylate. Yes; “4HBA” is 4-hydroxybutyl acrylate; “HEAA” is N-2-hydroxyethylacrylamide; “AA” is acrylic acid; “AM” is acrylamide.

(Example 21)
286 parts by mass (100 parts by mass as the solid content of the polymer) of the polymer (A-39) solution obtained in Synthesis Example 39, which is the polymer (A), and the peroxide cross-linking agent (B). Benzoyl oxide (Sigma Aldrich Japan Co., Ltd., sample name B-1) 0.2 parts by mass, Carbodilite (registered trademark) V-01 (Nisshinbo Chemical Co., Ltd., sample name C-1) which is a carbodiimide crosslinking agent (C) ) 0.3 parts by mass, Duranate (trademark) 24A-100 (hexamethylene diisocyanate bullet type, manufactured by Asahi Kasei Chemicals Corporation, sample name D-2) which is an isocyanate crosslinking agent (D) 0.2 parts by mass, imidazole compound (E) 0.01 parts by mass of 1-methylimidazole (manufactured by Tokyo Chemical Industry Co., Ltd., sample name E-1) is mixed at room temperature (25 ° C.) for 10 minutes, and adhesive A solution in which the agent composition was dissolved was obtained.

  This solution is applied onto a peeled PET film (Mitsubishi Resin, MRF38, thickness: 38 μm) so that the thickness after drying is 25 μm, and dried at 130 ° C. for 3 minutes to form an adhesive layer. Then, the pressure-sensitive adhesive layer side was further bonded to a PET film (trade name Lumirror (registered trademark) S10 # 25, thickness: 23 μm, manufactured by Toray Industries, Inc.) to prepare a pressure-sensitive adhesive sheet (1).

(Examples 22-30, Comparative Examples 19-27)
Except for using the polymers synthesized in Synthesis Examples 40 to 57, carbodiimide crosslinking agents, imidazole compounds, isocyanate crosslinking agents, and other additives at the composition ratios shown in Table 12 and Table 13 below. In the same manner as in Example 21, a solution in which the pressure-sensitive adhesive composition was dissolved and a pressure-sensitive adhesive sheet were prepared, and pressure-sensitive adhesive sheets (2) to (10) and comparative pressure-sensitive adhesive sheets (1) to (9) were prepared. Obtained. Peroxide crosslinking agents B-1 and B-2, carbodiimide crosslinking agents C-1, C-2 and C-3, isocyanate crosslinking agents D-2 and D-3, and imidazole compounds E-1, E- Details of 2, E-3 and E-4 and other additives H-1, H-2, H-3 and H-4 are as follows.

  Each performance was evaluated according to the following method about the adhesive sheet of Examples 21-30 and Comparative Examples 19-27 obtained as mentioned above.

1. Metal corrosion inhibition / prevention Immediately after production of a pressure-sensitive adhesive sheet having a pressure-sensitive adhesive layer (in each case, the coating layer of the solution in which the pressure-sensitive adhesive composition is dissolved is dried (crosslinked) at 130 ° C. for 3 minutes to form a pressure-sensitive adhesive layer. Within 10 minutes), the adhesive layer surface was bonded to an aluminum foil, and then allowed to stand in an atmosphere of 60 ° C. and 90% RH for 2 days, and the corrosivity at that time was observed. In Tables 12 and 13 below, “◯” indicates no change, and “x” indicates whitening.

2. Adhesive strength Immediately after preparation of the adhesive sheet having the adhesive layer (in each example, the coating layer of the solution in which the adhesive composition was dissolved was dried (crosslinked) at 130 ° C. for 3 minutes to form an adhesive layer. Within a minute), the adhesive sheet was cut into a width of 25 mm, and this was pressure-bonded to the stainless steel plate by reciprocating once with a 2 kg roller, and left for 20 minutes in an atmosphere of 23 ° C. and 50% RH. Then, using a tensile tester, the adhesive tape / adhesive sheet test method described in JIS Z0237 (2000) at an exfoliation angle of 180 degrees and an exfoliation speed of 0.3 m / min in an atmosphere of 23 ° C. and 50% RH. The adhesive strength was measured accordingly.

3. 1. Adhesion to substrate At the time of measuring the adhesive strength, the adhesion to the adhesive sheet (base material) was evaluated. In Table 12 and Table 13 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.

4). Substrate contamination property 2. The contact angle of the polarizing plate surface before and after measuring the adhesive force was measured. The contact angle was measured according to the wettability test method for the substrate glass surface described in JIS R3257 (1999). In Table 12 and Table 13 below, “◯” indicates a change in the contact angle of the stainless steel plate surface before and after the adhesive strength measurement is 3 ° or less, and “×” indicates a change in the contact angle of the stainless steel plate surface before and after the adhesive strength measurement. Each case is shown.

5. Low temperature stability Immediately after preparation of a pressure-sensitive adhesive sheet having a pressure-sensitive adhesive layer (after forming a pressure-sensitive adhesive layer by drying (crosslinking) the coating layer of the solution in which the pressure-sensitive adhesive composition is dissolved in each example at 130 ° C. for 3 minutes. Within 10 minutes), the pressure-sensitive adhesive sheet was pressed against the stainless steel plate by a method of reciprocating once with a 2 kg roller, and left for 1 hour in an atmosphere of 23 ° C. and 50% RH. Then, the external appearance after leaving for 120 hours in -40 degreeC atmosphere was observed. In Tables 12 and 13, “◯” represents that foaming, floating, and peeling were not observed, and “X” represents that foaming, floating, and peeling were observed.

6). Transparency of the pressure-sensitive adhesive layer Immediately after the production of the pressure-sensitive adhesive sheet having the pressure-sensitive adhesive layer (in each case, the coating layer of the solution in which the pressure-sensitive adhesive composition is dissolved is dried (crosslinked) at 130 ° C. for 3 minutes to form the pressure-sensitive adhesive layer. Within 10 minutes), the transparency of the pressure-sensitive adhesive layer of the pressure-sensitive adhesive sheet was visually confirmed. In Table 12 and Table 13 below, “◯” represents a case where transparency was good, and “x” represents a case where white turbidity was observed in the pressure-sensitive adhesive layer.

7). Heat resistance Immediately after the preparation of the pressure-sensitive adhesive sheet having the pressure-sensitive adhesive layer (in each example, the coating layer of the solution in which the pressure-sensitive adhesive composition is dissolved is dried (crosslinked) at 130 ° C. for 3 minutes to form the pressure-sensitive adhesive layer. Within a minute), the pressure-sensitive adhesive sheet was pressure-bonded to the stainless steel plate by reciprocating once with a 2 kg roller, and left for 1 hour in an atmosphere of 23 ° C. and 50% RH. Thereafter, the appearance after leaving for 500 hours in an 80 ° C. atmosphere was observed. In Table 12 and Table 13 below, “◯” represents that foaming, floating, and peeling were not observed, and “X” represents that foaming, floating, and peeling were observed.

8). Moist heat resistance Immediately after preparation of the pressure-sensitive adhesive sheet having the pressure-sensitive adhesive layer (in each example, the coating layer of the solution in which the pressure-sensitive adhesive composition is dissolved is dried (crosslinked) at 130 ° C. for 3 minutes to form the pressure-sensitive adhesive layer. Within a minute), the pressure-sensitive adhesive sheet was pressure-bonded to the stainless steel plate by reciprocating once with a 2 kg roller, and left for 1 hour in an atmosphere of 23 ° C. and 50% RH. Thereafter, the appearance after being allowed to stand in an atmosphere of 60 ° C. and 90% RH for 500 hours was observed. In Table 12 and Table 13 below, “◯” represents that foaming, floating, and peeling were not observed, and “X” represents that foaming, floating, and peeling were observed.

9. Gel fraction Instead of the PET film having the pressure-sensitive adhesive layer prepared in Examples 21 to 30 and Comparative Examples 19 to 27, a polyester film subjected to a release treatment was used, and the solution in which the pressure-sensitive adhesive composition was dissolved was used. After coating on the peeled polyester film so that the thickness after drying is 25 μm, this coating layer is dried (crosslinked) at 130 ° C. for 3 minutes, and the pressure-sensitive adhesive layer is formed on the peeled polyester film. The gel fraction is measured within 10 minutes (immediately after production of a peeled polyester film having an adhesive layer) and after standing for 7 days in an atmosphere of 23 ° C. and 50% RH after the formation of the adhesive layer (adhesion processing). did. The gel fraction was obtained by weighing about 0.1 g of the pressure-sensitive adhesive composition immediately after the production of the release-treated polyester film having the pressure-sensitive adhesive layer and after standing for 7 days in an atmosphere of 23 ° C. and 50% RH. 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 12 and Table 13 below. In Table 12 and Table 13 below, the “immediately after blending” viscosity that defines the viscosity of the pressure-sensitive adhesive composition is within 10 minutes after the preparation of the pressure-sensitive adhesive composition is completed (each component is mixed for a predetermined time). Means the measured viscosity. Similarly, in the following Tables 12 and 13, “immediately after processing” that defines the gel fraction of the pressure-sensitive adhesive composition is the above-mentioned 9. It means the gel fraction measured for the sample immediately after the production of the peeled polyester film (within 10 minutes) having the pressure-sensitive adhesive layer in the gel fraction.

  As is clear from Table 12 and Table 13 above, the pressure-sensitive adhesive compositions (Examples 21 to 30) of the present invention are compared with the pressure-sensitive adhesive compositions (Comparative Examples 19 to 27) that are outside the scope of the present invention. The pot layer is excellent in pot life, and the pressure-sensitive adhesive layer can be crosslinked (cured) in a very short period (within 10 minutes) after the crosslinking treatment. From this, it is considered that the pressure-sensitive adhesive composition of the present invention can greatly improve both workability and productivity. Moreover, as is clear from Table 12 and Table 13 above, the pressure-sensitive adhesive sheets of Examples 21 to 30 of the present invention are more adhesive to the substrate and adherend contamination than the pressure-sensitive adhesive sheets of Comparative Examples 19 to 27. Properties, low-temperature stability, transparency of the pressure-sensitive adhesive layer, heat resistance and heat-and-moisture resistance.

Claims (6)

0-9 parts by mass of carboxyl group-containing monomer (a-1), 0-9 parts by mass of hydroxy group-containing (meth) acrylic monomer (a-2) and 99.9-82 parts by mass of (meth) acrylic acid ester Comprising monomer (a-3) (however, the total amount of carboxyl group-containing monomer (a-1) and hydroxy group-containing (meth) acrylic monomer (a-2) is not 0 parts by mass, and carboxyl group-containing monomer) (A-1), the hydroxy group-containing (meth) acrylic monomer (a-2), and the (meth) acrylic acid ester monomer (a-3) in a total amount of 100 parts by mass) 100 parts by weight of (meth) acrylic copolymer (A) having a weight average molecular weight of 100,000 to 2,000,000,
0.1 to 1 part by mass of the peroxide crosslinking agent (B) and 0.05 to 5 parts by mass of the carbodiimide crosslinking agent (C) with respect to 100 parts by mass of the (meth) acrylic copolymer (A),
A pressure-sensitive adhesive composition comprising:   The pressure-sensitive adhesive composition according to claim 1, further comprising 0.05 to 5 parts by mass of an isocyanate crosslinking agent (D) with respect to 100 parts by mass of the (meth) acrylic copolymer (A). In addition to 0.005-0.2 mass part of imidazole compound (E) represented by following Chemical formula 1 with respect to 100 mass parts of said (meth) acrylic copolymers (A). The pressure-sensitive adhesive composition described:

In Formula 1, R ¹ , R ² , and R ³ are each independently a hydrogen atom, a halogen atom, or a substituted or unsubstituted linear or branched chain having 1 to 10 carbon atoms. It is an alkyl group.   An optical member provided with the adhesive layer formed from the adhesive composition of any one of Claims 1-3.   A surface protection film provided with the adhesive layer formed from the adhesive composition of any one of Claims 1-3.   An adhesive sheet provided with the adhesive layer formed from the adhesive composition of any one of Claims 1-3.