JP6383210B2 - Adhesive composition, optical member and adhesive sheet - Google Patents

Description

  The present invention relates to a pressure-sensitive adhesive composition, an optical member, and a pressure-sensitive adhesive sheet. More specifically, the present invention relates to a pressure-sensitive adhesive composition containing a (meth) acrylic acid polymer, a cationic polymerizable monomer, a cationic photopolymerization initiator, a silane coupling agent, and a photosensitizer at a predetermined composition ratio. . Moreover, it is related with an optical member and an adhesive sheet provided with the adhesive layer formed from this adhesive composition.

  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. Along with this, improvement in workability and productivity of pressure-sensitive adhesives used in FPDs is required.

  Patent Document 1 discloses a pressure-sensitive adhesive for polarizing plates formed by irradiating an adhesive material containing an acrylic copolymer and a polyfunctional (meth) acrylate monomer with active energy rays. With this configuration, it is disclosed that the pressure-sensitive adhesive composition for an optical film is excellent in durability and light leakage even under high temperature and high temperature and high humidity conditions.

  Patent Document 2 discloses a (meth) acrylic acid ester polymer (A) having a weight average molecular weight of 600,000 to 2,000,000 and containing a monomer having a nitrogen atom as a monomer unit constituting the polymer, and an active energy. A pressure-sensitive adhesive composition containing a linear curable component (B) is disclosed. With this configuration, it is disclosed that the pressure-sensitive adhesive composition for an optical film is excellent in durability even under high temperature and high temperature and high humidity conditions.

JP 2006-235568 A JP2013-203899A

  However, the pressure-sensitive adhesive layer formed from the pressure-sensitive adhesive composition described in Patent Document 1 requires a long aging time of 10 days until it reaches practical pressure-sensitive adhesive performance after irradiation with active energy rays (see paragraph “Patent Document 1” 0035 "), there was a problem of low productivity. In addition, since the pot life is short, problems remain in terms of workability.

  The pressure-sensitive adhesive composition described in Patent Document 2 does not use the isocyanate-based crosslinking agent described in Patent Document 1, and has an active energy ray having a structure (isocyanurate structure) containing isocyanurate that is a trimer of isocyanate. A curable compound is used. Since the active energy ray-curable compound having an isocyanurate structure has low reactivity with the (meth) acrylic acid polymer, it still requires about half a day until it reaches the practical adhesive performance after irradiation with the active energy ray ( Patent Document 2 Paragraph “0124”).

  The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a pressure-sensitive adhesive composition that has a long pot life and excellent workability, and is excellent in productivity by reaching practical adhesive performance in a shorter aging time. Is to provide things. Moreover, the other objective of this invention is to provide the adhesive composition which is excellent in durability of the adhesive layer after hardening, and the adhesiveness to a base material.

  As a result of intensive studies to solve the above problems, the present inventors have found that a (meth) acrylic acid-based polymer, a cationic polymerizable monomer, a cationic photopolymerization initiator, a silane at a predetermined composition ratio. It has been found that the above problems can be solved by a pressure-sensitive adhesive composition containing a coupling agent and a photosensitizer, and the present invention has been completed.

  That is, one aspect of the present invention is: (A) a (meth) acrylic acid polymer having a weight average molecular weight of 1 million or more 100 parts by mass; (B) a cation polymerizable monomer 1 to 20 parts by mass; System photopolymerization initiator 0.05-4 parts by mass; (D) silane coupling agent 0.05-0.5 parts by mass; and (E) photosensitizer 0.05-2 parts by mass It is a composition. Another aspect of the present invention is an optical member and a pressure-sensitive adhesive sheet including a pressure-sensitive adhesive layer formed from such a pressure-sensitive adhesive composition.

  ADVANTAGE OF THE INVENTION According to this invention, the pot life is excellent in workability | operativity, and it can provide the adhesive composition which is excellent in productivity by reaching practical adhesive performance in a short aging time. Moreover, according to this invention, the adhesive composition excellent in durability of the adhesive layer after hardening and the adhesiveness to a base material can be provided.

  Embodiments of the present invention will be described below. In addition, this invention is not limited only to the following embodiment. In the present specification, “(meth) acrylate” and “(meth) acrylic acid” are generic names 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”.

  In this specification, “X to Y” indicating a range means “X or more and Y or less”. Unless otherwise specified, measurement of operation and physical properties is performed under conditions of room temperature (20 to 25 ° C.) / Relative humidity 40 to 50%.

[Adhesive composition]
One aspect of the present invention is: (A) (meth) acrylic acid polymer having a weight average molecular weight of 1 million or more 100 parts by mass; (B) 1-20 parts by mass of cationic polymerizable monomer; (C) cationic light A pressure-sensitive adhesive composition containing 0.05 to 4 parts by mass of a polymerization initiator; (D) 0.05 to 0.5 parts by mass of a silane coupling agent; and (E) 0.05 to 2 parts by mass of a photosensitizer. It is.

  The pressure-sensitive adhesive for polarizing plate is used for bonding the polarizing plate to the glass substrate of the liquid crystal cell. Particularly in a high-temperature and high-humidity environment, the contraction of the polarizing plate is large, and so-called light leakage occurs in the TN liquid crystal cell due to the contraction of the polarizing plate.

  In Patent Document 1, in order to suppress light leakage under such high-temperature and high-humidity conditions, an adhesive material containing an acrylic copolymer and a polyfunctional (meth) acrylate monomer is irradiated with active energy rays. A polarizing plate adhesive is disclosed. Here, referring to the examples of Patent Document 1, isocyanate crosslinking agents are used in all Examples (paragraph “0032”) Table 1). In the radical polymerization system, the pressure-sensitive adhesive is cured by ultraviolet rays in a short time, so that the crosslinking strain is large and the adhesion to the glass substrate is lowered. For this reason, it is estimated that the isocyanate type crosslinking agent is mix | blended for the purpose of adhesive improvement. The isocyanate-based crosslinking agent is a general-purpose crosslinking agent in the pressure-sensitive adhesive for polarizing plates, but since it is a thermosetting type, it requires a long aging time. Aging process) (paragraph “0035”). In addition, since it contains an isocyanate-based crosslinking agent that is a thermosetting component, crosslinking proceeds gradually even at room temperature, and the pot life is shortened.

  Since such a long-time aging treatment is not required, Patent Document 2 describes that a polyfunctional (meth) acrylate monomer / oligomer is suitable as an active energy curing component for an acrylic copolymer. In the example, tris (acryloxyethyl) isocyanurate is used. Although the pressure-sensitive adhesive composition of Patent Document 2 has a relatively long pot life, it requires an aging time of about half a day because it uses an isocyanurate-based curable compound (Patent Document 2, paragraph “0124”). This is considered that although the isocyanurate-based curable compound is rapidly activated by active energy rays, it takes time to reach a bridged structure, and therefore a certain amount of aging time is required.

  If the aging treatment takes time, there is a problem that the processing such as punching cannot be performed immediately after the pressure-sensitive adhesive composition is processed into, for example, a polarizing plate, and the productivity is lowered.

  On the other hand, the pressure-sensitive adhesive composition of the present invention has a long pot life and excellent workability because crosslinking does not proceed unless irradiated with ultraviolet rays. In addition, the conventional pressure-sensitive adhesive composition required aging for about half a day until reaching the practical pressure-sensitive adhesive performance, but according to the present invention, practical pressure-sensitive adhesive performance can be obtained even after aging within 1 hour. . In particular, when adhesive processing is performed on a roll-to-roll production line, practical adhesive performance can be obtained even after aging within one hour, so punching can be performed immediately, and productivity is greatly improved.

  In addition, the cationic polymerization system has a relatively slow cross-linking speed than the radical polymerization system, so that the cross-linking strain is small. In particular, without using an isocyanate-based curing agent, the substrate adhesion and reworkability (at the time of bonding) When the re-sticking becomes necessary, it is possible to ensure the performance that the adhesive is less likely to remain after peeling. Therefore, 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, and is excellent in reworkability. The pressure-sensitive adhesive composition of the present invention is excellent in durability when the pressure-sensitive adhesive layer is formed because the crosslinking density is appropriate. Furthermore, the pressure-sensitive adhesive composition of the present invention is also excellent in adherend contamination prevention properties.

  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 as a pressure-sensitive adhesive layer for optical members and pressure-sensitive adhesive sheets. Can be used for In particular, the pressure-sensitive adhesive composition of the present invention hardly causes light leakage due to the contraction of the polarizing plate that occurs under high temperature and high humidity storage. For this reason, the adhesive composition of this invention is suitable as an adhesive composition for polarizing plates.

  Hereinafter, each component which comprises an adhesive composition is demonstrated.

  The pressure-sensitive adhesive is also referred to as a pressure-sensitive adhesive, and is a kind of adhesive having adhesiveness (also referred to as tackiness) at normal temperature. In JIS K 6800-2006, “adhesive at normal temperature” , A substance that adheres to an adherend with light pressure. The tackiness can be observed by an inclined ball tack test defined by JIS Z0237-2009.

<(Meth) acrylic acid polymer (A)>
The pressure-sensitive adhesive composition of the present invention is a (meth) acrylic acid polymer (also referred to herein as “(meth) acrylic acid polymer (A)” or simply “component (A)”). including.

  The weight average molecular weight (Mw) of a component (A) is 1 million or more. When the weight average molecular weight of the copolymer is 1,000,000 or more, for example, it can withstand the stress generated by contraction of the polarizing plate under high temperature or high temperature and high humidity conditions. For this reason, durability of the bonding target object after applying an adhesive composition is high. Although the upper limit of the weight average molecular weight of a component (A) is not specifically limited, Usually, it is 2 million or less. Bonding property improves that a weight average molecular weight is 2 million or less. In addition, in this invention, the value of polystyrene conversion measured by the gel permeation chromatography as described in an Example shall be employ | adopted for a weight average molecular weight.

  As the (meth) acrylic acid polymer in the present invention, those having a crosslinking point such as a carboxyl group, a hydroxy group, and an amino group are used. Such a (meth) acrylic acid polymer is not particularly limited, and can be appropriately selected from those conventionally used for pressure-sensitive adhesive compositions. In particular, the (meth) acrylic acid ester monomer (a-1) below and at least one of a carboxyl group-containing monomer (a-2) and a hydroxy group-containing (meth) acrylic monomer (a-3) (meta) ) An acrylic acid polymer is preferably used.

((Meth) acrylic acid ester monomer (a-1))
A (meth) acrylic acid ester monomer (in this specification, “(meth) acrylic acid ester monomer (a-1)” or simply “component (a-1)”) is a hydroxy group in the molecule. (Meth) acrylic acid ester not containing 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, methyl-3-methoxy (meth) acrylate, 2-methoxyethyl (meth) acrylate, 2-ethoxyethyl (meth) acrylate, 3-methoxybutyl (Meth) acrylate, 2- (2-methoxyethoxy) ethyl (meth) acrylate, 2- (2-butoxyethoxy) ethyl (meth) acrylate, 4-butylphenyl (meth) acrylate, phenol (Meth) acrylate, 2,4,5-tetramethylphenyl (meth) acrylate, phenoxymethyl (meth) acrylate, phenoxyethyl (meth) acrylate, polyethylene oxide monoalkyl ether (meth) acrylate, polyethylene oxide monoalkyl ether ( (Meth) acrylate, polypropylene oxide monoalkyl ether (meth) acrylate, trifluoroethyl (meth) acrylate, pentadecafluorooxyethyl (meth) acrylate, 2-chloroethyl (meth) acrylate, 2,3-dibromopropyl (meth) acrylate And tribromophenyl (meth) acrylate.

  Among these, since the weight average molecular weight of the (meth) acrylic acid polymer (A) can be increased, methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, isopropyl (meth) acrylate, n-butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, 2-methoxyethyl (meth) acrylate, and 2-ethoxyethyl (meth) acrylate are preferred. However, since 2-methoxyethyl (meth) acrylate has a slightly lower copolymerization property than other monomers, when it is contained, (meth) acrylic acid ester monomer, carboxyl group-containing monomer and hydroxy group-containing (meta ) It is preferable that it is 10 mass parts or less with respect to 100 mass parts of total amounts of an acryl monomer, and it is more preferable that it is 5 mass parts or less.

  A component (a-1) may be used independently and may be used in combination of 2 or more type.

(Carboxyl group-containing monomer (a-2))
The carboxyl group-containing monomer (in this specification, also referred to as “carboxyl group-containing monomer (a-2)” or simply “component (a-2)”) has at least one carboxyl group in the molecule. Unsaturated monomer. 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.

  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.

  A component (a-2) may be used independently and may be used in combination of 2 or more type.

(Hydroxy group-containing (meth) acrylic monomer (a-3))
The hydroxy group-containing (meth) acrylic monomer (in this specification, also referred to as “hydroxy group-containing (meth) acrylic monomer (a-3)” or simply “component (a-3)”) is contained in the molecule. An acrylic monomer having a hydroxy group. 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.

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

  A component (a-3) may be used independently and may be used in combination of 2 or more type.

(Other monomers)
In addition to the components (a-1) to (a-3), other monomers copolymerizable with these can also be used in the (meth) acrylic acid polymer (A) of the present invention. Specific examples include acrylic monomers having an epoxy group such as glycidyl (meth) acrylate and methyl glycidyl (meth) acrylate; dimethylaminoethyl (meth) acrylate, diethylaminoethyl (meth) acrylate, N-tert-butyl Acrylic monomers having amino groups such as aminoethyl (meth) acrylate and methacryloxyethyltrimethylammonium chloride (meth) acrylate; (meth) acrylamide, N-methylol (meth) acrylamide, N-methoxymethyl (meth) acrylamide, N, Acrylic monomers having an amide group such as N-methylenebis (meth) acrylamide; 2-methacryloyloxyethyldiphenyl phosphate (meth) acrylate, trimethacryloyloxy Acrylic monomers having a phosphoric acid group such as ethyl phosphate (meth) acrylate and triacryloyloxyethyl phosphate (meth) acrylate; sulfopropyl (meth) acrylate sodium, 2-sulfoethyl (meth) acrylate sodium, 2-acrylamide-2 -Acrylic monomer having a sulfonic acid group such as sodium methylpropanesulfonate; Acrylic monomer having a urethane group such as urethane (meth) acrylate; p-tert-butylphenyl (meth) acrylate, o-biphenyl (meth) acrylate, etc. Acrylic vinyl monomer having a phenyl group; 2-acetoacetoxyethyl (meth) acrylate, vinyltrimethoxysilane, vinyltriethoxysilane, vinyltris (β-methoxyethyl) silane Vinyl monomers having silane groups such as lan, vinyltriacetylsilane, methacryloyloxypropyltrimethoxysilane; styrene, chlorostyrene, α-methylstyrene, vinyltoluene, vinyl chloride, vinyl acetate, vinyl propionate, acrylonitrile, vinylpyridine, etc. Can be mentioned. These other monomers may be used alone or in combination of two or more.

  However, in consideration of adhesiveness, the other monomer is preferably 10% by mass or less, more preferably 5% by mass or less with respect to the (meth) acrylic acid polymer (A) (the lower limit is 0% by mass).

  The (meth) acrylic acid polymer (A) is composed of 90 to 99.5 parts by mass of a (meth) acrylic acid ester monomer (a-1) and 0.5 to 10 parts by mass of a carboxyl group-containing monomer (a- 2) and at least one of a hydroxy group-containing (meth) acrylic monomer (a-3) (provided that the (meth) acrylic acid ester monomer, the carboxyl group-containing monomer, and the hydroxy group-containing (meth) acrylic monomer) Is preferably 100 parts by mass). By using the (meth) acrylic acid polymer (A) having such a composition, it is possible to further suppress a decrease in light leakage resistance and to prevent peeling from the substrate. The (meth) acrylic acid polymer (A) is composed of 95-99.5 parts by mass of a (meth) acrylic acid ester monomer (a-1) and 0.5-5 parts by mass of a carboxyl group-containing monomer (a- 2) and at least one of a hydroxy group-containing (meth) acrylic monomer (a-3) (provided that the (meth) acrylic acid ester monomer, the carboxyl group-containing monomer, and the hydroxy group-containing (meth) acrylic monomer) Is more preferably 100 parts by mass).

  The glass transition temperature of the (meth) acrylic acid polymer (A) is usually 0 ° C. or lower, and preferably −10 ° C. or lower. The adhesive performance as an adhesive can be ensured by being 0 degreeC or less. The glass transition temperature is preferably −70 ° C. or higher. Sufficient cohesive force is ensured by being −70 ° C. or higher. The glass transition temperature can be determined by differential scanning calorimetry (DSC).

  The production method of component (A) is not particularly limited, and conventionally known methods such as 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, and a spray polymerization method. This method 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.

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

<Cationically polymerizable monomer (B)>
The pressure-sensitive adhesive composition of the present invention contains a cationically polymerizable monomer (also referred to herein as “cationic polymerizable monomer (B)” or simply “component (B)”).

  The cationic polymerizable monomer is 1 to 20 parts by mass (solid content ratio) with respect to 100 parts by mass of the component (A). When the cationic polymerizable monomer is less than 1 part by mass, the adhesiveness is not expressed, and various physical properties necessary for the adhesive composition (adhesion to substrate, light leakage resistance, durability, adherend contamination) Preventability and reworkability). Further, when the cationic polymerizable monomer exceeds 20 parts by mass, crosslinking proceeds too much, so that the pressure-sensitive adhesive layer hardly follows the contraction of the polarizing plate under high temperature and high humidity conditions, which is caused by the generated stress. The light leakage resistance decreases due to photoelasticity. Further, durability is also reduced under severe conditions under a heat shock test. The cationically polymerizable monomer is preferably 2 to 20 parts by mass (solid content ratio) with respect to 100 parts by mass of the component (A) from the viewpoint of improving crosslinkability. Moreover, from a viewpoint of cost reduction, it is more preferable that a cationically polymerizable monomer is 10 mass parts or less with respect to 100 mass parts of component (A).

  The cationic polymerizable monomer is not particularly limited, and any conventionally known cationic polymerizable monomer can be used as long as it is cured by causing cationic polymerization. More specifically, the cationic polymerizable monomer includes at least one of a glycidyl group, an epoxycycloalkyl group, a vinyl ether group, an oxetane ring, a cyclic ether group, a cyclic acetal group, a cyclic lactone group, and a cyclic thioether group. And a spiro orthoester compound. Among these, from the viewpoint of reactivity, a monomer having at least one selected from the group consisting of a glycidyl group, an epoxycycloalkyl group, a vinyl ether group, and an oxetane ring is more preferable. Further, it is preferably a polyfunctional cationic polymerizable monomer having at least two glycidyl groups, epoxy cycloalkyl groups, vinyl ether groups, and oxetane rings.

  Examples of the monomer having a glycidyl group include ethylene glycol diglycidyl ether, diethylene glycol diglycidyl ether, propylene glycol diglycidyl ether, tripropylene glycol diglycidyl ether, neopentyl glycol diglycidyl ether, 1,4-butanediol diglycidyl ether. 1,6-hexanediol diglycidyl ether, trimethylolpropane triglycidyl ether, trimethylolpropane diglycidyl ether, polyethylene glycol diglycidyl ether, pentaerythritol tetraglycidyl ether, phenylglycidyl ether, glycerin diglycidyl ether, di Cyclopentadiene dimethanol diglycidyl ether

, 1,3-bis (oxiranylmethoxy) benzene (resorcinol diglycidyl ether), 2,2 ′-[(1-methylethylidene) bis (4,1-cyclohexanediyloxymethylene)] bisoxirane, etc. Bisphenol A type diglycidyl ether, bisphenol A type diglycidyl ether, bisphenol F type diglycidyl ether, bisphenol S type diglycidyl ether, bisphenol AD type diglycidyl ether, 3,3 ′, 5,5′-tetramethyl-4, Examples thereof include glycidyl etherified product of 4′-biphenol. Of these, neopentyl glycol diglycidyl ether, dicyclopentadiene dimethanol diglycidyl ether, hydrogenated bisphenol A type diglycidyl ether, and 1,3-bis (oxiranylmethoxy) benzene, particularly from the viewpoint of reactivity. Is preferred.

  Examples of the bisphenol A type epoxy compound include Epicron 840, Epicron 840-S, Epicron 850, Epicron 850-S, Epicron 850-CRP, Epicron 850-LC (manufactured by Dainippon Ink & Chemicals, Inc.), Epicoat 825, Epicoat 827, Epicoat 828, Epicoat 828EL, Epicoat 828XA, Epicoat 834 (manufactured by Japan Epoxy Resin Co., Ltd.), Rica Resin BPO-20E, Rika Resin BEO-60E (manufactured by Shin Nippon Rika Co., Ltd.), etc. It is commercially available.

  Examples of the hydrogenated bisphenol A type epoxy compound include Denacol EX-252 (manufactured by Nagase ChemteX Corporation), SR-HBA (manufactured by Sakamoto Pharmaceutical Co., Ltd.), Epikote YX-8000, Epikote RXE- 21 (above, made by Japan Epoxy Resin Co., Ltd.), Rica Resin HBE-100 (above, made by Shin Nippon Rika Co., Ltd.) and the like are commercially available.

  Examples of the monomer having an epoxycyclohexyl group include 3 ′, 4′-epoxycyclohexylmethyl-3,4-epoxycyclohexanecarboxylate, 2- (3,4-epoxycyclohexyl-5,5-spiro-3, 4-epoxy) cyclohexane-metadioxane, bis (3,4-epoxycyclohexylmethyl) adipate, bis (3,4-epoxy-6-methylcyclohexylmethyl) adipate, 3,4-epoxy-6-methylcyclohexyl-3 ′ , 4′-epoxy-6′-methylcyclohexanecarboxylate, methylene bis (3,4-epoxycyclohexane), di (3,4-epoxycyclohexylmethyl) ether of ethylene glycol, ethylene bis (3,4-epoxycyclohexanecarboxylate) ), Ε-Capro Lactone-modified 3,4-epoxycyclohexylmethyl-3 ′, 4′-epoxycyclohexanecarboxylate, trimethylcaprolactone-modified 3,4-epoxycyclohexylmethyl-3 ′, 4′-epoxycyclohexanecarboxylate, β-methyl-δ-valero Examples include lactone-modified 3,4-epoxycyclohexylmethyl-3 ′, 4′-epoxycyclohexanecarboxylate and 1.2: 8,9 diepoxy limonene. Among these, 3 ′, 4′-epoxycyclohexylmethyl-3,4-epoxycyclohexanecarboxylate is particularly preferable from the viewpoint of reactivity.

  Examples of the monomer having a vinyl ether group include diethylene glycol divinyl ether, triethylene glycol divinyl ether, cyclohexyl vinyl ether, polyethylene glycol divinyl ether, 1,4-cyclohexanedimethanol divinyl ether, and the like. Of these, triethylene glycol divinyl ether and cyclohexyl vinyl ether are particularly preferable from the viewpoint of easy availability and handling.

  As the cationic polymerizable monomer having a glycidyl group, an epoxycycloalkyl group, or a vinyl ether group as described above, a commercially available product may be used, and examples of the commercially available product include Epolite (registered trademark) series (Kyoeisha Chemical Co., Ltd.). Epicote (registered trademark) series (manufactured by Mitsubishi Chemical Corporation), Epicron (registered trademark) series (manufactured by DIC Corporation), Epototo (registered trademark) series (manufactured by Toto Kasei Corporation), Adeka Resin (registered trademark) Series (manufactured by ADEKA Corporation), Denacol (registered trademark) series (manufactured by Nagase ChemteX Corporation), Dow epoxy series (manufactured by Dow Chemical Japan Co., Ltd.), Tepic (registered trademark) series (manufactured by Nissan Chemical Industries, Ltd.) , DVE-3, CHVE (manufactured by BASF Japan Ltd.), Celoxide ( Such as recording trademark) series (manufactured by Daicel), and the like.

  Examples of the monomer having an oxetane ring include 2-ethylhexyloxetane, xylylenebisoxetane, 3-ethyl-3-hydroxymethyloxetane, 1,4-bis [(3-ethyloxetane-3-yl) methoxymethyl] benzene. , 3-ethyl-3- (2-ethylhexyloxymethyl) oxetane, 3,3 ′-(oxybismethylene) bis (3-ethyloxetane) (3-ethyl-3 {[(3-ethyloxetane-3- Yl) methoxy] methyl} oxetane), 3-ethyl-3- (phenoxymethyl) oxetane, 3-ethyl-3- (cyclohexyloxymethyl) oxetane, phenol novolac oxetane, 1,3-bis [(3-ethyloxetane- 3-yl) methoxy] benzene and the like. Of these, 2-ethylhexyloxetane, xylylenebisoxetane, and 3,3 ′-(oxybismethylene) bis (3-ethyloxetane) are particularly preferable from the viewpoint of availability and handling.

  As the compound containing the oxetane ring, a commercially available product may be used. )) And the like.

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

<Cationic photopolymerization initiator (C)>
The pressure-sensitive adhesive composition of the present invention contains a cationic photopolymerization initiator (also referred to herein as “cationic photopolymerization initiator (C)” or simply “component (C)”).

  The photopolymerization initiator contained in the pressure-sensitive adhesive composition generates a cation (acid) in the light irradiation step for the pressure-sensitive adhesive composition described later, and reacts with the reactivity of the (meth) acrylic acid polymer or the cationic polymerizable monomer. Increase. When the pressure-sensitive adhesive composition contains a cationic photopolymerization initiator, practical pressure-sensitive adhesive performance can be obtained by aging in a short time. Furthermore, various performances as an adhesive can be satisfied.

  The cationic photopolymerization initiator is 0.05 to 4 parts by mass (solid content ratio) with respect to 100 parts by mass of the component (A). When the cationic photopolymerization initiator is less than 0.05 parts by mass, adhesiveness is not expressed, and various physical properties necessary for the adhesive composition (adhesion to substrate, light leakage resistance, durability, covering resistance) (Attachment prevention and reworkability) cannot be obtained. In addition, when the cationic photopolymerization initiator exceeds 4 parts by mass, crosslinking proceeds too much, so that the pressure-sensitive adhesive layer hardly follows the contraction of the polarizing plate under high temperature and high humidity conditions, and light caused by the generated stress. Light leakage resistance decreases due to elasticity. Furthermore, the durability as an adhesive layer is also reduced. From the viewpoint of crosslinkability and durability, the cationic photopolymerization initiator is preferably 0.1 to 3 parts by mass (solid content ratio) with respect to 100 parts by mass of the component (A).

  As the cationic photopolymerization initiator, a compound usually used as a photoacid generator can be used without particular limitation. Specific examples include onium salts such as aromatic diazonium salts, aromatic iodonium salts, and aromatic sulfonium salts, and iron-allene complexes.

  Examples of the aromatic diazonium salt include benzenediazonium hexafluoroantimonate, benzenediazonium hexafluorophosphate, and benzenediazonium hexafluoroborate.

  Examples of the aromatic iodonium salt include diphenyliodonium tetrakis (pentafluorophenyl) borate, diphenyliodonium hexafluorophosphate, diphenyliodonium hexafluoroantimonate, di (4-nonylphenyl) iodonium hexafluorophosphate, di (4-t- Butylphenyl) iodonium hexafluorophosphate, di (4-t-butylphenyl) iodonium hexafluoroantimonate, tricumyliodonium tetrakis (pentafluorophenyl) borate, (4-methylphenyl) [4- (2-methylpropyl) And di (4-alkylphenyl) iodonium hexafluorophosphate such as phenyl] iodonium hexafluorophosphate. It is.

  Examples of the aromatic sulfonium salt include triphenylsulfonium hexafluorophosphate, triphenylsulfonium hexafluoroantimonate, triphenylsulfonium tetrakis (pentafluorophenyl) borate, diphenyl [4- (phenylthio) phenyl] sulfonium hexafluoroantimonate, 4,4′-bis [diphenylsulfonio] diphenyl sulfide bishexafluorophosphate, 4,4′-bis [di (β-hydroxyethoxy) phenylsulfonio] diphenyl sulfide bishexafluoroantimonate, 4,4′-bis [Di (β-hydroxyethoxy) phenylsulfonio] diphenylsulfide bishexafluorophosphate, 7- [di (p-toluyl) sulfonio] 2-Isopropylthioxanthone hexafluoroantimonate, 7- [di (p-toluyl) sulfonio] -2-isopropylthioxanthone tetrakis (pentafluorophenyl) borate, 4-phenylcarbonyl-4'-diphenylsulfonio-diphenyl sulfide hexafluorophosphate 4- (p-tert-butylphenylcarbonyl) -4′-diphenylsulfonio-diphenyl sulfide hexafluoroantimonate, 4- (p-tert-butylphenylcarbonyl) -4′-di (p-toluyl) sulfonio- Examples thereof include diphenyl sulfide, tetrakis (pentafluorophenyl) borate, and diphenyl [4- (phenylthio) phenyl] sulfonium phosphate.

  Examples of iron-allene complexes include xylene-cyclopentadienyl iron (II) hexafluoroantimonate, cumene-cyclopentadienyl iron (II) hexafluorophosphate, xylene-cyclopentadienyl iron (II) -tris. And (trifluoromethylsulfonyl) methanide.

  Among these, the cationic photopolymerization initiator is preferably an aromatic iodonium salt or an aromatic sulfonium salt from the viewpoint of reactivity.

  As the cationic photopolymerization initiator, commercially available products may be used. For example, CPI-100P, 101A, 200K, 210S (triarylsulfonium salt) (manufactured by San Apro Co., Ltd.), Kayarad (registered trademark) PCI-220, PCI- 620 (manufactured by Nippon Kayaku Co., Ltd.), UVI-6990, UVI-6992 (manufactured by Union Carbide), Adekaoptomer SP-150, SP-170 (manufactured by ADEKA), CI-5102 (manufactured by Nippon Soda Co., Ltd.) ), CIT-1370, 1682 (Nippon Soda Co., Ltd.), CIP-1866S, 2048S, 2064S (Nippon Soda Co., Ltd.), DPI-101, 102, 103, 105 (Midori Chemical Co., Ltd.), MPI -103, 105 (Midori Chemical Co., Ltd.), BBI-101, 102, 103, 1 5, (Midori Chemical Co., Ltd.), TPS-101, 102, 103, 105 (Midori Chemical Co., Ltd.), MDS-103, 105 (Midori Chemical Co., Ltd.), DTS-102, 103 (Midori Chemical Co., Ltd.) Product), PI-2074 (manufactured by Rhodia Japan), WPI-113, 116 (manufactured by Wako Pure Chemical Industries, Ltd.), Irgacure 250 (manufactured by BASF Japan Ltd.), and the like.

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

<Silane coupling agent (D)>
The pressure-sensitive adhesive composition of the present invention contains a silane coupling agent (also referred to herein as “silane coupling agent (D)” or simply “component (D)”). By using a silane coupling agent, the mechanical strength of the pressure-sensitive adhesive layer is improved, and a pressure-sensitive adhesive layer having excellent durability can be obtained.

  A silane coupling agent is 0.05-0.5 mass part (solid content ratio) with respect to 100 mass parts of component (A). When the silane coupling agent is less than 0.05 parts by mass, the durability of the pressure-sensitive adhesive layer is lowered. If it exceeds 0.5 parts by mass, the durability will be lowered, and the light leakage will be deteriorated. The amount of component (D) is preferably 0.07 to 0.45 parts by mass (solid content ratio), more preferably 0.1 to 0.3 parts by mass (solid content ratio).

  Examples of the silane coupling agent that can be used in the present invention include methyltrimethoxysilane, dimethyldimethoxysilane, trimethylmethoxysilane, n-propyltrimethoxysilane, ethyltrimethoxysilane, diethyldiethoxysilane, and n-butyltrimethyl. Methoxysilane, n-hexyltriethoxysilane, n-octyltrimethoxysilane, phenyltrimethoxysilane, diphenyldimethoxysilane, cyclohexylmethyldimethoxysilane, vinyltrichlorosilane, vinyltrimethoxysilane, vinyltriethoxysilane, vinyltris (β-methoxy Ethoxy) silane, 3-glycidoxypropylmethyldiethoxysilane, β- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, γ-glycidoxy Propyltrimethoxysilane, γ-glycidoxypropyltriethoxysilane, γ-methacryloxypropylmethyldimethoxysilane, γ-methacryloxypropyltrimethoxysilane, γ-methacryloxypropylmethyldiethoxysilane, γ-methacryloxypropyltri Ethoxysilane, 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 -Mel Hept trimethoxysilane, .gamma.-mercaptopropyl methyl dimethoxy silane, bis - (3- [triethoxysilyl] propyl) tetrasulfide, 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 and the like with each functional group in an arbitrary ratio can also be used.

  In addition, it is preferable to use what does not have an isocyanate group as a silane coupling agent.

  In the present invention, a silane coupling agent alkoxy oligomer (silane coupling agent oligomer) may be used as the silane coupling agent. In the silane coupling agent alkoxy 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. , A compound having an organic functional group in the molecule. Since the silane coupling agent oligomer has an alkoxy group, it exhibits adhesion to glass used for liquid crystal panels and the like. In addition, by having an organic functional group, the silane coupling agent oligomer is excellent in compatibility and adhesion with the (meth) acrylic acid polymer, and is a so-called anchor to the (meth) acrylic acid polymer. The effect appears. However, the present invention is not limited by such consideration.

  Examples of the organic functional group of the silane coupling agent alkoxy oligomer include vinyl group, epoxy group, styryl group, (meth) acryloyl group, methacryloxy group, acryloxy group, amino group, ureido group, chloropropyl group, mercapto group, polysulfide group, etc. Is mentioned. 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 is increased, the viscosity of the silane coupling agent oligomer is increased and may be pasty or 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.

  Although it does not specifically limit as a silane coupling agent oligomer, For example, the homopolymer of the above-mentioned silane compound, a copolymer, etc. are mentioned.

  The silane coupling agent may be synthesized or a commercially available product may be used. Examples of commercially available silane coupling agents include Shin-Etsu Silicone (registered trademark) KBM-303, KBM-403, KBE-402, KBM-403, KBE-502, KBE-503, KBM-5103, KBM-573, KBM-802, KBM-803, KBE-846, X-41-1805 (a silane coupling agent oligomer having a mercapto group, a methoxy group and an ethoxy group), X-41-1810 (a mercapto group, a methyl group and a methoxy group) Silane coupling agent oligomer), X-41-1053 (silane coupling agent oligomer having epoxy group, methoxy group and ethoxy group), X-41-1058 (silane coupling having epoxy group, methyl group and methoxy group) Agent oligomer) (Shin-Etsu Chemical Co., Ltd.) Etc., Ltd.) Co., Ltd., and the like.

  Among these silane coupling agents, KBM-303, KBM-403, KBE-402, KBM-403, KBM-5103, KBM-573, KBM-802, KBM-803, KBE-846, X-41-1805, X-41-1810 is preferable, and KBM-403 and X-41-1810 are more preferable.

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

<Photosensitizer (E)>
The pressure-sensitive adhesive composition of the present invention contains a photosensitizer (also referred to herein as “photosensitizer (E)” or simply “component (E)”). A photosensitizer is a compound that absorbs energy rays and efficiently generates cations from a cationic photopolymerization initiator. In addition to a cationic photopolymerization initiator, a photosensitizer should be used. Since the radical polymerization reaction proceeds, the use of a photosensitizer improves the reactivity of cationic polymerization, and can improve the mechanical strength and adhesiveness of the adhesive composition of the present invention.

  A photosensitizer is 0.05-2 mass parts (solid content ratio) with respect to 100 mass parts of component (A). When the photosensitizer is less than 0.05 parts by mass, no tackiness is exhibited and various physical properties necessary for the pressure-sensitive adhesive composition (adhesion to substrate, light leakage resistance, durability, adherend resistance) Preventability and reworkability). Moreover, when the photosensitizer exceeds 2 parts by mass, the crosslinking proceeds too much, so that the pressure-sensitive adhesive layer hardly follows the contraction of the polarizing plate under high temperature and high humidity conditions, and is caused by photoelasticity caused by the generated stress. Light leakage resistance is reduced. In addition, durability is also reduced. The blending amount of the component (E) is preferably 0.1 to 1.5 parts by mass (solid content ratio), more preferably 0.1 to 1.0 parts by mass, from the viewpoints of crosslinkability and durability. It is.

  The photosensitizer may be any compound that increases the light activity of the composition, and any type of sensitization mechanism such as energy transfer, electron transfer, and proton transfer may be used.

  As photosensitizers, benzoin derivatives such as benzoin methyl ether, benzoin isopropyl ether, α, α-dimethoxy-α-phenylacetophenone; benzophenone, 2,4-dichlorobenzophenone, methyl o-benzoylbenzoate, 4,4 ′ Benzophenone derivatives such as bis (dimethylamino) benzophenone and 4,4′-bis (diethylamino) benzophenone; anthracene, 9,10-dibutoxyanthracene, 9,10-dichloroanthracene, 2-ethyl-9,10-dimethoxyanthracene Anthracene derivatives such as 9-hydroxymethylanthracene, 9-bromoanthracene, 9-chloroanthracene, 9,10-dibromoanthracene, 2-ethylanthracene, 9,10-dimethoxyanthracene; Acridone derivatives such as cridone, N-butyl-2-chloroacridone, N-methylacridone, 2-methoxyacridone, N-ethyl-2-methoxyacridone; thioxanthone, 2,4-diethylthioxanthene-9- Thioxanthone derivatives such as diethylthioxanthone such as ON, 1-chloro-4-propoxythioxanthone, 2-chlorothioxanthone; coumarin derivatives such as coumarin-1, coumarin-6H, coumarin-110, coumarin-102; 2- (4-dimethyl Base styryl derivatives such as aminostyryl) benzoxazole, 2- (4-dimethylaminostyryl) benzothiazole, 2- (4-dimethylaminostyryl) naphthothiazole, distyrylbenzene, di (4-methoxystyryl) benzene, di ( 3, 4 Distyrylbenzene derivatives such as 5-trimethoxy styryl) benzene; chloro anthraquinone, anthraquinone derivatives such as 2-methyl anthraquinone.

  Among these sensitizers, the photosensitizer is preferably 2,4-diethylthioxanthen-9-one from the viewpoint of reactivity.

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

<Antistatic agent (F)>
The pressure-sensitive adhesive composition of the present invention preferably contains an antistatic agent (also referred to herein as “antistatic agent (F)” or simply “component (F)”). When the pressure-sensitive adhesive composition contains an antistatic agent, the surface resistance value of the pressure-sensitive adhesive layer formed from the pressure-sensitive adhesive composition decreases. Thereby, after bonding to the liquid crystal cell etc. which are adherends, when it becomes necessary to peel by the bonding mistake etc., generation | occurrence | production of static electricity can be suppressed effectively. As a result, it is possible to stably prevent dust from being easily attached to the surface of the polarizing plate, the liquid crystal alignment is easily disturbed, and the electrostatic breakdown of the peripheral circuit element is easily caused. it can.

  As the antistatic agent that can be used in the present invention, an ionic conductive agent such as an ionic liquid, a surfactant, and the like are preferably used.

  Examples of the ionic conductive agent include phosphonium ion, pyridinium ion, pyrrolidinium ion, imidazolium ion, guanidinium ion, ammonium ion, isouronium ion, thiouronium ion, piperidinium ion, pyrazolium ion, sulfonium ion, Cation components such as quaternary ammonium and quaternary phosphonium, and halogen ions, nitrate ions, sulfate ions, phosphate ions, perchlorate ions, thiocyanate ions, thiosulfate ions, sulfite ions, tetrafluoroborate ions, hexafluorophos And substances having an anionic component such as phosphate ion, formate ion, oxalate ion, acetate ion, trifluoroacetate ion, and alkylsulfonate ion. More specifically, 1-allyl-3-methylimidazolium chloride, 1,3-dimethylimidazolium chloride, 1,3-dimethylimidazolium dimethyl phosphate, 1-ethyl-3-methylimidazolium chloride, 1- Ethyl-3-methylimidazolium bromide, 1-ethyl-3-methylimidazolium iodide, 1-ethyl-3-methanesulfonate, 1-ethyl-3-methylimidazolium tetrafluoroborate, 1-ethyl-3-methyl Imidazolium hexafluorophosphate, 1-ethyl-3-methylimidazolium-p-toluenesulfonate, 1-butyl-3-methylimidazolium chloride, 1-hexyl-3-methylimidazolium chloride, 1-methyl-1- Propyl-pyrrolidinium bis (trifluoro Methanesulfonyl) imide, 1-methyl-1-methylpyrrolidinium bromide, 1-butyl-1-methylpiperidinium bromide, 1-ethylpyridinium chloride, 1-ethylpyridinium bromide, 1-butylpyridinium chloride, 1-butyl Pyridinium bromide, 1-butyl-3-methylpyridinium chloride, 1-ethyl-3-methylpyridinium ethyl sulfate, 1-butyl-4-methylpyridinium chloride, 1-butyl-4-methylpyridinium hexafluorophosphate, trimethylpropylammonium Bis (trifluoromethanesulfonyl) imide, tributylmethylammonium bis (trifluoromethanesulfonyl) imide, tetrabutylammonium chloride, tetrabutylammonium bromide, cyclo Hexyl trimethyl ammonium bis (trifluoromethanesulfonyl Suho) imide, tetrabutyl phosphonium bromide and the like.

  As the ionic conductive agent, bis (fluorosulfonyl) imide salts represented by the following formula (1) are also preferably used.

However, in said formula (1), A is a fluorine atom or a C1-C6 fluoroalkyl group; X is the group which consists of hydrogen, an alkali metal, alkaline-earth metal, ammonium, phosphonium, alkylammonium, and alkylphosphonium. Any one of cations selected from Preferably, A is a fluorine atom and X is H ⁺ , Li ⁺ , Na ⁺ or K ⁺ .

As the surfactant, a nonionic surfactant or an ionic surfactant can be used. Nonionic surfactants include fluorosurfactants such as fluoroaliphatic polymer esters (for example, FC-4430, FC-4432, manufactured by 3M), polyethylene glycol alkyl ethers, polyoxyalkylene alkyl ethers. Etc. Examples of the ionic surfactant include cationic surfactants such as C _{8 to} C ₂₂ alkyltrimethylammonium halides and anionic surfactants such as alkyl sulfates.

  The compounding amount of the component (F) is preferably 0.2 to 5 parts by mass (solid content ratio) with respect to 100 parts by mass of the component (A), more preferably 0.8 to 2.5 parts by mass ( Solid content ratio).

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

<Other ingredients>
As described above, the active energy ray-curable component having an isocyanate-based crosslinking agent / isocyanurate requires a long aging time, and the active energy ray-curable component having an isocyanate-based crosslinking agent / isocyanurate is Unreacted monomers can adversely affect worker health.

  Therefore, considering the shortening of the aging time of the pressure-sensitive adhesive composition and the safety of workers, the pressure-sensitive adhesive composition of the present invention substantially contains an active energy ray-curable component having an isocyanate-based crosslinking agent and isocyanurate. It is preferable not to contain. The isocyanurate structure refers to a structure represented by the following formula (2), which is generated by a trimerization reaction of isocyanate.

  A pressure-sensitive adhesive composition substantially free of an isocyanate-based crosslinking agent has a long pot life and a significantly shortened aging time. Further, by using an active energy ray-curable compound having no isocyanurate structure, there is an effect that the aging time is remarkably shortened.

  Moreover, it is preferable that NCO content rate (%) which represented the amount of isocyanate groups which exist in an adhesive composition in mass fraction is substantially 0%. Specifically, the pressure-sensitive adhesive composition preferably has an NCO content measured in accordance with JIS K1603-1 (2007) of less than 0.5% (lower limit 0%).

Furthermore, the presence or absence of an isocyanurate structure can be analyzed by means such as measurement of carbonyl 1690 to 1700 cm ⁻¹ of the isocyanurate structure by FT-IR.

  Other crosslinking agents can be added as long as the effects of the present invention are not limited. For example, the pressure-sensitive adhesive composition of the present invention may contain a carbodiimide crosslinking agent. 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 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.

  Some carbodiimide crosslinking agents have an isocyanate group represented by the following formula (3) (for example, Carbodilite (registered trademark) V-01 (Nisshinbo Chemical Co., Ltd.)). It is preferable to use a carbodiimide cross-linking agent that does not contain any of them.

  The term “carbodiimide crosslinking agent having no isocyanate group” means that the NCO content (%) representing the amount of isocyanate group present in the carbodiimide curing agent in terms of mass fraction is substantially 0%. Say. Specifically, a carbodiimide crosslinking agent having an NCO content of less than 0.5% measured according to JIS K1603-1 (2007) is used.

  Examples of commercially available carbodiimide crosslinking agents having no isocyanate group include Carbodilite (registered trademark) V-03 (NCO content: 0%), Carbodilite (registered trademark) V-09 (NCO content: 0%) (above, Nisshinbo Chemical Co., Ltd.).

  When mix | blending a carbodiimide crosslinking agent, it is preferable that a compounding quantity is 0.05-5 mass parts with respect to 100 mass parts of components (A). A carbodiimide crosslinking agent may be used independently and may be used in combination of 2 or more type.

  The pressure-sensitive adhesive composition of the present invention includes, as additives, a curing accelerator, a lithium salt, an inorganic filler, a softening agent, an antioxidant, an anti-aging agent, a stabilizer, a tackifier resin, a modified resin (polyol resin, phenol) Resin, acrylic resin, polyester resin, polyolefin resin, epoxy resin, epoxidized polybutadiene resin, etc.), leveling agent, antifoaming agent, plasticizer, dye, pigment (colored pigment, extender pigment, etc.), treatment agent, UV blocker, Additives such as optical brighteners, dispersants, heat stabilizers, light stabilizers, UV absorbers, 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 (registered trademark) TK-1 (manufactured by Mitsui Chemicals, Inc.), and the like.

  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 component (A).

  Moreover, since a component (A) can be used for a composition as it is after superposing | polymerizing, the adhesive composition may contain the solvent used at the time of superposition | polymerization. Furthermore, you may dilute with a solvent so that coating may be easy. That is, the pressure-sensitive adhesive composition may further contain a solvent.

  At this time, examples of the solvent used in the pressure-sensitive adhesive composition include ethyl acetate, toluene, and methyl ethyl ketone.

<Manufacturing method>
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 at room temperature or as necessary (for example, warming to a temperature of 30 to 40 ° C.) and stirring for 5 minutes to 5 hours until uniform with a stirrer or the like. it can. Moreover, you may use a component (A) in the state containing the solvent after superposition | polymerization. Furthermore, you may dilute with a solvent at the time of mixing of each component, or after mixing each component. Examples of the solvent used at this time include ethyl acetate, toluene, methyl ethyl ketone, and the like.

<Properties>
The viscosity of the pressure-sensitive adhesive composition of the present invention is not particularly limited. However, considering the ease of coating and the ease of controlling the thickness of the pressure-sensitive adhesive layer formed from the composition, immediately after blending at 25 ° C. (10 minutes after mixing each component for a predetermined time) The viscosity measured with a B-type viscometer is preferably 300 to 7000 mPa · s. For example, when used as an adhesive for an optical member, the viscosity immediately after preparation at 25 ° C. (within 10 minutes after mixing each component for a predetermined time) is more preferably 1000 to 6000 mPa · s, and further preferably 2500 to 5000 mPa · s. s.

  The pot life can be evaluated by comparing the viscosity of the composition immediately after blending the adhesive composition with the viscosity of the composition after 12 hours from preparation (blending). It is preferable that the composition after 12 hours from blending does not gel. When the viscosity of the composition immediately after blending the adhesive composition is 100%, the viscosity of the composition after 12 hours from blending is preferably within 130%, preferably within 110%. More preferred (lower limit is 100%). If it is such a range, it will become an adhesive composition which has the outstanding workability | operativity. 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.

  In the present specification, “immediately after” 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).

[Adhesive layer]
The pressure-sensitive adhesive layer obtained from the pressure-sensitive adhesive composition of the present invention is formed from the coating film of the pressure-sensitive adhesive composition as described above, and is provided with pressure-sensitive adhesiveness by treatment with active energy irradiation. .

  Since the pressure-sensitive adhesive composition of the present invention contains a cationic photopolymerization initiator and a photosensitizer, an acid is generated by performing an active energy irradiation treatment, and a (meth) acrylic acid polymer and a cationic polymerizable monomer. It is photopolymerized by the body growth reaction. Thereby, 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 within 1 hour after pressure-sensitive adhesive processing (after active energy irradiation treatment).

  The pressure-sensitive adhesive layer obtained from the pressure-sensitive adhesive composition of the present invention is obtained by coating the pressure-sensitive adhesive composition as described above on a release film or a substrate, and the one before and after crosslinking is used. Including. An optical member or pressure-sensitive adhesive sheet having a pressure-sensitive adhesive layer formed from a pressure-sensitive adhesive composition before crosslinking is subjected to an active energy irradiation treatment during use, and is used by giving the pressure-sensitive adhesive layer (pressure-sensitive adhesive composition) tackiness. That's fine.

  The crosslinking of the pressure-sensitive adhesive composition is generally performed after the pressure-sensitive adhesive composition is applied to the substrate, but it is also possible to transfer a pressure-sensitive adhesive layer comprising the pressure-sensitive adhesive composition after crosslinking to the substrate. is there. Moreover, after apply | coating said adhesive composition on a peeling film and drying the coating film of an adhesive composition as needed, you may laminate | stack a base material on a coating film.

  Moreover, after apply | coating said adhesive composition on a peeling film and drying the coating film of an adhesive composition as needed, another peeling film (2nd peeling film) from which peeling force differs is coated. It may be laminated on top. According to such an embodiment, not only the pressure-sensitive adhesive composition can be transported but also in the air, for example, because the production of the pressure-sensitive adhesive composition and the use of the pressure-sensitive adhesive composition are performed in another place. Photocuring can proceed without being affected by oxygen. In addition, by providing a predetermined difference in the peeling force between the two peeling films, it is possible to prevent the adhesive from partially following when the peeling film on the side having a low peeling force is peeled off.

  As such a release film, for example, a release layer such as a polyethylene resin is applied to a polyester film such as polyethylene terephthalate (PET) or polyethylene naphthalate, or a polyolefin film such as polypropylene or polyethylene, and a release layer is provided. Is mentioned. It is preferable to use a release film having a thickness in the range of 20 to 150 μm.

  Although it does not specifically limit as said base material, For example, the optical film etc. which are used for liquid crystal displays, such as a polarizing plate, a polarizing layer protective film, a viewing angle expansion film, an anti-glare film, a phase difference plate, are mentioned. . In particular, the pressure-sensitive adhesive composition of the present invention can effectively suppress the occurrence of light leakage even when the substrate is a polarizing plate. In one embodiment of the present invention, an optical member in which an adhesive layer is formed on a polarizing plate is provided. In addition, since the pressure-sensitive adhesive composition in the present invention can adhere to a polarizer or the like with durability, the polarizer itself produced by stretching an iodine-containing polyvinyl alcohol resin that is a raw material of a polarizing plate is also used as a substrate. Can be used. The same applies to a polarizer in which one side of the polarizer is covered with a protective film such as triacetylcellulose or polyethylene terephthalate.

  Examples of the material of the base material include polyvinyl alcohol, polyethylene terephthalate, triacetyl cellulose, polycarbonate, liquid crystal polymer, cycloolefin, polyimide, polyamide, polyamideimide, polyphenylene ether, polyether ketone, polyether ether ketone, polysulfone, and polyether. Examples include sulfone, polyphenylene sulfide, polyarylate, acrylic resin, alicyclic structure-containing polymer, and aromatic polymer.

  The base material may be subjected to a surface treatment. Examples of such surface treatment include primer treatment, corona treatment, flame treatment, and the like, and corona treatment is particularly preferable. By using the base material that has been subjected to such a surface treatment, the adhesiveness of the pressure-sensitive adhesive layer to the base film can be further improved.

  The method for applying the pressure-sensitive adhesive composition is not particularly limited, and for example, a bar coating method, a knife coating method, a roll coating method, a blade coating method, a die coating method, a gravure coating method, or the like may be used. If necessary, it is preferable to dry after applying a pressure-sensitive adhesive composition to which a solvent has been added to form a coating film. As drying conditions, it is usually preferable to be within a range of 10 to 10 minutes at 50 to 150 ° C. As the solvent, for example, toluene, xylene, ethyl acetate, butyl acetate, methyl ethyl ketone, ethyl isobutyl ketone, methyl alcohol, ethyl alcohol, isopropyl alcohol and the like are preferable, and the concentration of the pressure-sensitive adhesive composition when adding the solvent is 5 to A value in the range of 30% by mass is preferable.

  The coating 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, but is preferably 1 to 100 μm, more preferably 5 to 30 μm.

  An active energy ray irradiation process is performed with respect to the coating film of the adhesive composition prepared as mentioned above, and an adhesive layer is formed. Examples of such active energy rays include ultraviolet rays and electron beams. In the case of ultraviolet rays, a high-pressure mercury lamp, an electrodeless lamp, a xenon lamp, a metal halide lamp, or the like can be used. In the case of an electron beam, an electron beam accelerator or the like may be used as a light source.

  When the coating film of an adhesive composition is formed on a peeling film, it is preferable to perform irradiation of an active energy ray from the peeling film side. Thereby, it can irradiate efficiently, without damaging base materials, such as a polarizing plate.

The irradiation amount of the active energy ray in the active energy ray irradiation treatment is, for example, in the range of 50 to 1000 mJ / cm ² , and it is preferable to irradiate with the irradiation amount in the range of 100 to 700 mJ / cm ² , and 120 to 500 mJ. It is more preferable to irradiate with a dose of / cm ² . By setting the irradiation amount of active energy rays to 50 mJ / cm ² or more, durability when exposed to environmental changes and desired pressure-sensitive adhesive properties can be obtained. On the other hand, by setting the irradiation amount of active energy rays to 1000 mJ / cm ² or less, crosslinking can be performed without destroying the pressure-sensitive adhesive layer or the substrate.

For example, when the adhesive composition is irradiated with ultraviolet rays using a metal halide lamp, the irradiation is performed at, for example, 500 to 2000 mW / cm ² . The irradiation time may be arbitrarily set, but for example, irradiation may be performed for 1 to 10 seconds. The atmosphere during the irradiation treatment is not particularly limited and may be performed in the air, but from the viewpoint that photocuring can proceed without being affected by oxygen in the air, inert such as nitrogen gas or argon gas It may be performed in a gas atmosphere. Further, the irradiation treatment may be performed at room temperature, or may be performed on a stage heated to 40 to 80 ° C.

[Optical members, adhesive sheets]
This invention also provides an optical member and an adhesive sheet provided with the adhesive layer formed from the adhesive composition of this invention.

<Optical member>
Preferred examples of the optical member include a polarizing plate, a retardation plate, an optical film for plasma display, and a conductive film for touch panel. Among these, the adhesive composition of this invention is excellent in the adhesiveness of a polarizing plate and glass. Of course, the present invention is not limited to the above-described form, and can be used for bonding other members. In one embodiment of the present invention, an optical member in which the pressure-sensitive adhesive layer is formed on a polarizing plate is provided.

  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.

  Since the pressure-sensitive adhesive composition of the present invention exhibits excellent flexibility, particularly when used in a polarizing plate, it can follow the shrinkage of the polarizing plate over time and can obtain excellent light leakage resistance. In addition, since the pressure-sensitive adhesive composition of the present invention has excellent durability, the pressure-sensitive adhesive layer can be prevented from floating or peeling off due to heat treatment or high-humidity treatment.

  When using the adhesive composition of this invention for an optical member, it is preferable that the gel fraction of the adhesive layer 1 hour after an adhesive process (active energy ray irradiation process) is 65-92%, 70-90 % Is more preferable. 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. After the pressure-sensitive adhesive processing, the gel fraction of the pressure-sensitive adhesive layer after being stored for 7 days in an atmosphere of 23 ° C. and 45% RH is 95 to 105%, assuming that the gel fraction after 1 hour from the pressure-sensitive adhesive processing is 100%. It is preferable that it is 97 to 103%. Such an adhesive layer maintains stable practical adhesive performance over a long period of time and is excellent in stability. In order to set the gel fraction as described above, the conditions may be appropriately selected, for example, by adjusting the amount of each component added to the above range.

  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 1 to 6 (N / 25 mm), and more preferably about 2 to 5 (N / 25 mm). If the adhesive strength is within such a range, the adhesive performance can be ensured and the reworkability can be advantageous. 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 an optical member has a long pot life and excellent workability, reaches a practical pressure-sensitive adhesive performance within a short time of 1 hour after pressure-sensitive adhesive processing, and greatly improves productivity. . Furthermore, the pressure-sensitive adhesive layer obtained from the pressure-sensitive adhesive composition of the present invention used for an optical member has not only excellent light leakage resistance, but also has an appropriate pressure-sensitive adhesive force and adhesion to a substrate for an optical member, Excellent durability, adherend resistance, and reworkability.

<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 pressure-sensitive adhesive sheet, various known thin leaf members such as rubber foam, paper, and aluminum foil are used in addition to the above. 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 an adhesive sheet, it is preferable that the gel fraction of the adhesive layer of the adhesive layer 1 hour after an active energy ray irradiation process is 65-92%, 70-90 % Is more preferable. 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. After the pressure-sensitive adhesive processing, the gel fraction of the pressure-sensitive adhesive layer after being stored for 7 days in an atmosphere of 23 ° C. and 45% RH is 95 to 105%, assuming that the gel fraction after 1 hour from the pressure-sensitive adhesive processing is 100%. It is preferable that it is 97 to 103%. Such an adhesive layer maintains stable practical adhesive performance over a long period of time and is excellent in stability. In order to set the gel fraction as described above, the conditions may be appropriately selected, for example, by adjusting the amount of each component added to the above range.

  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), more preferably about 0.1 to 10 (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 effects of the present invention will be described using the following examples and comparative examples. However, the technical scope of the present invention is not limited only to the following examples. The solid content and viscosity of the (meth) acrylic acid polymer solution obtained in the synthesis example, the viscosity of the pressure-sensitive adhesive composition (solution), and the weight average molecular weight of the component (A) were measured by the following methods. went.

<Solid content>
About 1 g of the (meth) acrylic acid polymer solution was precisely weighed in a precisely weighed glass dish. After drying at 105 ° C. for 1 hour, the temperature was returned to room temperature, and the total mass of the glass dish and the remaining solid content was precisely weighed. The mass of the glass dish is X, the total mass of the glass dish before drying and the (meth) acrylic acid polymer solution is Y, and the total mass Z of the glass dish and the residual solid content is solid according to the following formula 1. Minutes were calculated.

<Viscosity>
The (meth) acrylic acid polymer solution 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 (solution) was measured twice immediately after blending the pressure-sensitive adhesive composition (solution) and 12 hours after blending.

<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 mass 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 refluxing device 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 solution of a (meth) acrylic acid polymer (sample name: A-1). The obtained (meth) acrylic acid 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 (meth) acrylic acid polymer (A-1) was 1,600,000.

(Synthesis Examples 2-14)
In Synthesis Example 1, the (meth) acrylic acid polymer was obtained by performing the same operation as in Synthesis Example 1 except that the composition of the monomer component was changed to the composition shown in Table 2. The solutions (A-2) to (A-15) were obtained. Moreover, solid content and viscosity of the obtained (meth) acrylic acid polymer (A-2) to (A-15) solution, and (meth) acrylic acid polymer (A-2) to (A-15). ) Was measured. The results are shown in Table 2 below.

Example 1
500 parts by mass of the (meth) acrylic acid polymer solution obtained in Synthesis Example 1 (100 parts by mass as the solid content of the (meth) acrylic acid polymer (A)), a cationic polymerizable monomer (B ) Neopentyl glycol diglycidyl ether (manufactured by Tokyo Chemical Industry Co., Ltd., sample name B-1) 4 parts by mass, iodonium being cationic photopolymerization initiator (C), (4-methylphenyl) [4- (2 -Methylpropyl) phenyl] -hexafluorophosphate (1-) 2 parts by mass (sample name C-1) (Irgacure 250 (iodonium, (4-methylphenyl) [4- (2-methylpropyl) phenyl] -hexa Fluorophosphate (1-): propylene carbonate = 75: 25 (w: w), BASF Japan, 2.5 parts by mass), silane coupling agent (D) A certain Shin-Etsu Silicone (registered trademark) KBM-403 (3-glycidoxypropylmethyldiethoxysilane, manufactured by Shin-Etsu Chemical Co., Ltd., sample name D-1) 0.1 parts by mass, and a photosensitizer (E) After adjusting 1 mass part of some 2,4-diethylthioxanthen-9-one (Tokyo Chemical Industry Co., Ltd., sample name E-1) using ethyl acetate so that solid content concentration may be 17 mass%, The mixture was mixed at room temperature (25 ° C.) for 10 minutes to obtain an adhesive composition (solution).

  This solution was applied onto a peeled PET film (Mitsubishi Resin, MRF38, thickness: 38 μm) with a baker applicator so that the thickness after drying was 25 μm, and dried at 90 ° C. for 3 minutes to adhere. An agent layer was formed. Thereafter, a polarizing plate or another release film (second release film) having a different peeling force was laminated to obtain a polarizing plate or an adhesive sheet on which an adhesive layer was formed.

The active energy ray irradiation treatment was performed on the pressure-sensitive adhesive layer formed on the polarizing plate or between the release films under the following conditions. The active energy ray irradiation treatment was performed within 3 minutes from the above lamination.
Equipment used: Eye Grandage ECS-401GX (made by Eye Graphics Co., Ltd.)
Light source: Metal halide lamp Irradiation amount: 1000 mJ / cm ²
Conveyor speed: 5 m / min.

(Examples 2-9, Comparative Examples 1-15)
(Meth) acrylic acid polymers synthesized in the above synthesis examples, active energy ray-curable compounds, photopolymerization initiators, silane coupling agents, photosensitizers at the composition ratios shown in Table 5 and Table 6 below. , Except that an antistatic agent and other additives were used, in the same manner as in Example 1, preparation of a pressure-sensitive adhesive composition (solution) and preparation of a polarizing plate with a pressure-sensitive adhesive layer or a pressure-sensitive adhesive sheet It was. Here, the pressure-sensitive adhesive composition (solution) was adjusted using ethyl acetate so that the solid concentration was 17% by mass. In addition, active energy ray hardening-type compound B-1-7, B'-8-B'-9, photoinitiator C-1-2, C'-3, C-4-5, silane coupling agent D Details of -1 to 2, photosensitizer E-1, antistatic agents F-1 to F-3, and other additives G-1 to G-7 are as follows. Moreover, the mass part in following Table 5 and Table 6 is not the addition amount of each product but the addition amount of the active ingredient contained in a product. For example, Irgacure 250 used for C-1 is not the amount of Irgacure 250 added, but iodonium, (4-methylphenyl) [4- (2-methylpropyl) phenyl] -hexafluorophosphate contained in Irgacure 250. Amount.

  In order to evaluate the practical pressure-sensitive adhesive performance of the pressure-sensitive adhesive layer, each performance of the polarizing plate or pressure-sensitive adhesive sheet on which the pressure-sensitive adhesive layers according to Examples and Comparative Examples were formed was evaluated according to the following methods. In the following evaluation, “within 1 hour after production” means to be subjected to the test within 1 hour after the active energy ray irradiation treatment.

1. Gel fraction Using the adhesive sheet produced in Examples 1-9 and Comparative Examples 1-15, the gel fraction of the adhesive composition was measured. The gel fraction was measured by the following method. That is, after the active energy ray irradiation treatment, the pressure-sensitive adhesive sheet was stored in an atmosphere of 23 ° C. and 45% RH. 5 minutes, 1 hour, and 7 days after the active energy ray irradiation treatment, about 0.1 g of the pressure-sensitive adhesive composition was weighed, and the weight W ₁ (g) was measured. This was collected in a sample bottle, and about 30 g of ethyl acetate was added and left for 24 hours. The contents of the sample bottle after a lapse of a predetermined time are filtered off with a 200 mesh stainless steel wire mesh (the weight of the membrane is W ₂ (g)), and the wire mesh and the residue are dried at 90 ° C. for 1 hour. ₃ (g) was measured. The gel fraction was calculated from these measured values according to the following mathematical formula 2.

2. Light leakage resistance Immediately after the production of a polarizing plate with an adhesive layer, the polarizing plate is cut into 120 mm (polarizing plate MD direction) × 60 mm and 120 mm (polarizing plate TD direction) × 60 mm so as to overlap each surface of the glass plate. Then, autoclaving was performed for 20 minutes at 50 ° C. and 0.49 MPa (5 kg / cm ² ). Then, it preserve | saved in 85 degreeC atmosphere, and the external appearance 120 hours and 500 hours after the preservation | save start was observed. In Tables 3 and 4 below, “◎” indicates that no light leakage was observed after 120 hours and 500 hours, and “◯” indicates that no light leakage was observed after 120 hours. Indicates that light leakage was observed, respectively.

3. Durability Immediately after producing a polarizing plate with a pressure-sensitive adhesive layer, the polarizing plate was cut into 120 mm (polarizing plate MD direction) × 60 mm, and bonded to alkali-free glass (Corning Co., Ltd., Eagle XG), 50 ° C., Autoclaving was performed for 20 minutes under the condition of 0.49 MPa (5 kg / cm ² ). Thereafter, the appearance after storage for 500 hours in an atmosphere of 85 ° C. and an atmosphere of 60 ° C. and 95% RH was observed. In addition, a heat shock test was performed by repeating 200 cycles for two cycles of 30 minutes (first stage) at −40 ° C. and 30 minutes (second stage) at 85 ° C., and the appearance after the test was observed. . In Tables 3 and 4 below, “◯” indicates that foaming, floating, and peeling were not observed, and “X” indicates that one or more of foaming, floating, and peeling was observed.

4). Adhesive force Immediately after the production of a polarizing plate provided with an adhesive layer, the polarizing plate was cut to a width of 25 mm and bonded to alkali-free glass (Corning Co., Ltd., Eagle XG), and 50 ° C., 0.49 MPa (5 kg / cm). Autoclaving was performed for 20 minutes under the conditions of ² ). Using a tensile tester, in an atmosphere of 23 ° C. and 45% RH, with a peel angle of 180 degrees and a peel rate 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 Tables 5 and 6 below, “◯” indicates that the adhesive was not peeled off from the substrate, and “x” indicates that the 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 3 and 4 below, “◯” indicates that the change in the contact angle of the glass plate surface before and after the measurement of the adhesive force is 3 ° or less, and “X” indicates the change in the contact angle of the glass plate surface before and after the measurement of the adhesive force. Indicates that the angle exceeds 3 °.

7). Surface resistance value Immediately after the preparation of the polarizing plate provided with the pressure-sensitive adhesive layer, the surface resistance of the pressure-sensitive adhesive layer surface of the polarizing plate was measured at 23 ° C. and 45% RH using a resistivity meter Hirestar UP (Mitsubishi Chemical Corporation). It was measured. The applied voltage was 100V.

8). Reworkability 4. The peeled state was observed when measuring the adhesive strength. In Tables 5 and 6 below, “◯” indicates that interface fracture was observed, and “×” indicates that adhesive was transferred to the glass plate (adhered body) and / or cohesive failure was observed. Each is shown.

  As is clear from Table 5 and Table 6 above, the pressure-sensitive adhesive compositions of the present invention (Examples 1 to 9) have a long pot life and reach practical pressure-sensitive adhesive performance even after aging within a short time of 1 hour. . Furthermore, the pressure-sensitive adhesive layer formed from the pressure-sensitive adhesive composition of the present invention (Examples 1 to 9) is excellent in adhesion to the substrate and durability, and is also excellent in light leakage resistance. In addition, the composition of the comparative example 15 did not have adhesiveness.

Claims (6)

(A) 100 parts by mass of a (meth) acrylic acid polymer having a weight average molecular weight of 1,000,000 to 2,000,000 ;
(B) Cationic polymerizable monomer 1-20 parts by mass;
(C) Cationic photopolymerization initiator 0.05 to 4 parts by mass;
(D) a silane coupling agent 0.05 to 0.5 parts by weight; and (E) seen containing a photosensitizer 0.05-2 parts by weight, the active energy ray-curable with isocyanate crosslinking agent and isocyanurate A pressure-sensitive adhesive composition containing substantially no components .   The (meth) acrylic acid polymer (A) is 90-99.5 parts by mass of (meth) acrylic acid ester monomer (a-1) and 0.5-10 parts by mass of carboxyl group-containing monomer (a -2) and at least one of a hydroxy group-containing (meth) acrylic monomer (a-3) (however, the (meth) acrylic acid ester monomer, the carboxyl group-containing monomer, and the hydroxy group-containing (meth) acrylic) The total amount of monomers is 100 parts by mass), and the pressure-sensitive adhesive composition according to claim 1.   The pressure-sensitive adhesive composition according to claim 1 or 2, further comprising (F) an antistatic agent. An optical member provided with the adhesive layer formed from the adhesive composition of any one of Claims 1-3 . The optical member according to claim 4 , wherein the pressure-sensitive adhesive layer is formed on a polarizing plate. An adhesive sheet provided with the adhesive layer formed from the adhesive composition of any one of Claims 1-3 .