JP2011132269A - Pressure-sensitive adhesive composition and optical film - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a pressure-sensitive adhesive composition which is excellent in durability and void generation preventiveness in a high temperature or high temperature/humidity environment and ensures a short curing period without using an organotin compound, and an optical film with the pressure-sensitive adhesive. <P>SOLUTION: The pressure-sensitive adhesive composition includes an acrylic copolymer (A) having a reactive functional group, an isocyanate compound (B) added in an amount of 5-30 pts.wt. based on 100 pts.wt. of the acrylic copolymer (A), a zirconium compound (C), and a chelating agent (D). <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an acrylic pressure-sensitive adhesive composition and an optical film. Specifically, a pressure-sensitive adhesive composition used for attaching an optical film such as a polarizing film or a retardation film to an adherend such as a liquid crystal cell, and an optical film having a pressure-sensitive adhesive layer formed from the pressure-sensitive adhesive composition About.

  A liquid crystal display device usually includes a liquid crystal cell in which a liquid crystal component oriented in a predetermined direction is sandwiched between two supporting substrates such as glass and an optical film such as a polarizing film, a retardation film, and a brightness enhancement film. In many cases, an adhesive is used when laminating optical films or sticking an optical film to a liquid crystal cell.

  Liquid crystal display devices are widely used as display devices for personal computers, televisions, car navigation systems, and the like. Accordingly, there is a demand for an adhesive that is excellent in durability even when used under severe environments such as high temperature and high humidity, that is, does not cause peeling or generation of bubbles even when used for a long period of time. Also, under severe conditions such as high temperature and high humidity, the optical film undergoes large dimensional changes such as shrinkage and expansion, and the stress generated by such dimensional changes cannot be relaxed by the adhesive layer. Stress becomes uneven. As a result, there is a problem of so-called “white spots” in which light leaks from the periphery of the liquid crystal display device and becomes white.

  The present inventors have proposed a pressure-sensitive adhesive composition containing an acrylic copolymer and a specific amount of an isocyanate compound as a pressure-sensitive adhesive composition excellent in durability and suppression of white spots (Patent Document 1; Application No. 2008-330230 (unpublished)). An optical film having a pressure-sensitive adhesive layer formed from such a pressure-sensitive adhesive composition has excellent durability even under a high temperature or high temperature and high humidity environment and can suppress the occurrence of white spots. However, since the pressure-sensitive adhesive composition described in Patent Document 1 uses an isocyanate compound as a crosslinking agent, it requires a long curing period of about 10 days at room temperature and about 4 days at 35 ° C. There was a problem of being inferior.

  In order to improve such problems, Patent Document 2 discloses a pressure-sensitive adhesive using dibutyltin dilaurate as a catalyst for promoting a crosslinking reaction between an isocyanate compound and an acrylic resin. However, organotin compounds are pointed out to be toxic to living organisms, and pressure-sensitive adhesives that can shorten the curing period without using organotin compounds are required. In addition, since the organotin compound also acts as a condensation catalyst for silanol, the condensation reaction of the silane coupling agent added to the pressure-sensitive adhesive composition used in the liquid crystal display device is promoted, and the effect of the silane coupling agent is improved. It was sometimes reduced.

  Patent Document 3 discloses an adhesive using a zirconium compound as a crosslinking agent. However, since the pressure-sensitive adhesive described in Patent Document 3 uses a zirconium compound as a crosslinking agent, it is inferior in durability under a high temperature environment and cannot be used for a liquid crystal display device that requires heat resistance.

Japanese Patent Application No. 2008-330230 (unpublished) JP 2007-138056 A Japanese Patent Laid-Open No. 01-178666

  The present invention provides a pressure-sensitive adhesive composition that is excellent in durability and whitening property and has a short curing period without using an organic tin compound, and an optical film having a pressure-sensitive adhesive layer formed from the pressure-sensitive adhesive composition. With the goal.

  As a result of intensive studies to solve the above problems, the present inventors have found that an acrylic copolymer (A) having a reactive functional group, an isocyanate compound (B), a zirconium compound (C), a chelate It discovered that the said subject could be solved by using the adhesive formed from the adhesive composition containing an agent (D). That is, the present invention has the following configuration in order to solve the above problems.

(1) an acrylic copolymer (A) containing a reactive functional group;
5 parts by weight or more and 30 parts by weight or less of the isocyanate compound (B) added to 100 parts by weight of the acrylic copolymer (A);
A zirconium compound (C);
A pressure-sensitive adhesive composition comprising a chelating agent (D).
(2) With respect to 100 parts by weight of the acrylic copolymer (A), 0.001 part by weight or more and 0.1 part by weight or less, a zirconium compound (C) to be added,
The pressure-sensitive adhesive composition according to (1), comprising a chelating agent (D) to be added in an amount of 50 times or more based on the weight of the zirconium compound (C).
(3) The acrylic copolymer (A) contains 0.5% by weight or more and 5% by weight or less of a carboxyl group-containing monomer containing a carboxyl group as the reactive functional group as a copolymer component. The pressure-sensitive adhesive composition according to (1) or (2).

(4) It further includes an acrylic copolymer (E) containing a reactive functional group, which is different from the acrylic copolymer (A), and the isocyanate compound (B) contains the acrylic copolymer ( The pressure-sensitive adhesive composition according to (1), which is added to 100 parts by weight of a mixture of A) and the acrylic copolymer (E).
(5) The zirconium compound (C) and the chelating agent (D) are added to 100 parts by weight of the mixture of the acrylic copolymer (A) and the acrylic copolymer (E) ( The pressure-sensitive adhesive composition according to 2).
(6) The acrylic copolymer (A) contains 0.5% by weight or more and 5% by weight or less of a carboxyl group-containing monomer containing a carboxyl group as the reactive functional group as a copolymer component. ,
The acrylic copolymer (E) has a carboxyl group-containing monomer containing a carboxyl group as the reactive functional group in an amount of 0.1% by weight to 5% by weight and a hydroxyl group as the reactive functional group. The pressure-sensitive adhesive composition according to the above (4) or (5), which contains 0.01 to 5% by weight of a hydroxyl group-containing monomer as a copolymer component.
(7) Any of (4) to (6) above, wherein the acrylic copolymer (A) and the acrylic copolymer (E) are contained in a weight ratio of 50/50 or more and 99/1 or less. The pressure-sensitive adhesive composition according to any one of the above.

(8) The pressure-sensitive adhesive composition according to any one of (1) to (7), wherein the zirconium compound (C) is a zirconium complex having two ligands.
(9) The pressure-sensitive adhesive composition according to any one of (1) to (8), wherein the chelating agent (D) is acetylacetone or ethyl acetoacetate.
(10) An optical film having an adhesive layer formed from the adhesive composition according to any one of (1) to (9).
(11) A liquid crystal display device comprising the optical film according to (10).

  According to the pressure-sensitive adhesive composition for an optical film and the optical film with the pressure-sensitive adhesive according to the present invention, the curing period is short and the productivity is excellent, and the durability is good even in a high temperature or high temperature and high humidity environment. Occurrence can be suppressed.

It is sectional drawing of the optical film which concerns on this Embodiment. It is sectional drawing of the optical film which concerns on the modification of this Embodiment. It is sectional drawing of the liquid crystal display device which concerns on this Embodiment. It is sectional drawing of the liquid crystal display device which concerns on the modification of this Embodiment.

  As a result of intensive studies, the present inventors have found that an acrylic copolymer (A) containing a reactive functional group, an isocyanate compound (B), a zirconium compound (C), a chelating agent (D), By using the pressure-sensitive adhesive composition to which is added, the pressure-sensitive adhesive composition (hereinafter referred to as “single pressure-sensitive adhesive composition”) has a short curing period and can achieve both durability and suppression of white spots. Found that it can provide. Moreover, as a result of intensive studies to solve the above-mentioned problems, the present inventors are different from the acrylic copolymer (A) containing a reactive functional group and the acrylic copolymer (A). Using a pressure-sensitive adhesive composition in which an isocyanate compound (B), a zirconium compound (C), and a chelating agent (D) are added to a mixture with an acrylic copolymer (E) containing a reactive functional group Thus, it was found that a pressure-sensitive adhesive composition (hereinafter sometimes referred to as “mixed pressure-sensitive adhesive composition”) capable of achieving both durability and suppression of white spots can be provided with a short curing period.

[First Embodiment]
(Single pressure-sensitive adhesive composition)
The pressure-sensitive adhesive composition according to the first embodiment of the present invention includes an acrylic copolymer (A) containing a reactive functional group, an isocyanate compound (B), a zirconium compound (C), and a chelating agent. (D). In the pressure-sensitive adhesive composition according to the first embodiment, the reactive functional group of the acrylic copolymer (A) and the isocyanate compound (B) undergo a crosslinking reaction and contribute to the crosslinking reaction of the isocyanate compound (B). It is thought that the isocyanate group that was not reacted forms a multimer as a reaction product formed by reacting with water in the environment, thereby having good adhesive properties.

  In the first embodiment, the acrylic copolymer (A) includes an acrylic acid ester monomer and a methacrylic acid ester monomer (hereinafter referred to as “acrylic”) as a copolymer component in the copolymer. A monomer having a (meth) acrylic acid ester and a reactive functional group, the main component of which may be described as “(meth) acryl”) Is a copolymer obtained by copolymerizing The acrylic copolymer (A) means a copolymer containing 80% by weight or more of (meth) acrylic acid ester, and a copolymer containing 90% by weight or more is preferable.

  The (meth) acrylic acid ester monomer is not particularly limited as long as it has a (meth) acrylic acid ester structure. For example, methyl (meth) acrylate, ethyl (meth) acrylate, n-butyl ( (Meth) acrylate, i-butyl (meth) acrylate, t-butyl (meth) acrylate, n-octyl (meth) acrylate, i-octyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, n-nonyl (meth) C1-C18 straight or branched chain of (meth) acrylic acid such as acrylate, i-nonyl (meth) acrylate, n-decyl (meth) acrylate, n-dodecyl (meth) acrylate, stearyl (meth) acrylate Alkyl esters, as well as one or more of these various derivatives are used. Rukoto can.

  The constituent component in the acrylic copolymer (A) according to the first embodiment has a reactive functional group for the purpose of reacting the acrylic copolymer (A) with the isocyanate compound (B). Contains monomer. In addition, what is a monomer (meth) acrylic acid ester having a reactive functional group is also contained as a copolymer component in the acrylic copolymer (A) when defining the acrylic copolymer. It is counted as the amount of (meth) acrylic acid ester monomer.

  Examples of the monomer having a reactive functional group include a carboxyl group-containing monomer, a hydroxyl group-containing monomer, a glycidyl group-containing monomer, an amide group, an N-substituted amide group-containing monomer, and a tertiary amino acid. 1 type (s) or 2 or more types, such as a group containing monomer, can be used.

  Examples of the carboxyl group-containing monomer include acrylic acid, methacrylic acid, maleic acid, maleic anhydride, fumaric acid, crotonic acid, itaconic acid, citraconic acid, cinnamic acid, succinic acid monohydroxyethyl (meth) acrylate, and maleic acid. Acid monohydroxyethyl (meth) acrylate, fumarate monohydroxyethyl (meth) acrylate, phthalate monohydroxyethyl (meth) acrylate, 1,2-dicarboxycyclohexane monohydroxyethyl (meth) acrylate, (meth) acrylic acid dimer , Ω-carboxy-polycaprolactone mono (meth) acrylate, and the like can be used.

  Examples of the hydroxyl group-containing monomer include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, and 3-methyl- 3-hydroxybutyl (meth) acrylate, 1,1-dimethyl-3-butyl (meth) acrylate, 1,3-dimethyl-3-hydroxybutyl (meth) acrylate, 2,2,4-trimethyl-3-hydroxypentyl (Meth) acrylate, 2-ethyl-3-hydroxyhexyl (meth) acrylate, glycerin mono (meth) acrylate, polypropylene glycol mono (meth) acrylate, polyethylene glycol mono (meth) acrylate, poly (ethylene glycol-propylene group) Call) mono (meth) acrylate, N- methylol acrylamide, allyl alcohol, can be used methallyl alcohol.

  Examples of the glycidyl group-containing monomer include glycidyl (meth) acrylate, 3,4-epoxycyclohexylmethyl (meth) acrylate, glycidyl vinyl ether, 3,4-epoxycyclohexyl vinyl ether, glycidyl (meth) allyl ether, 3,4 -Epoxy cyclohexyl (meth) allyl ether etc. can be used.

  Examples of amide group and N-substituted amide group-containing monomers include acrylamide, methacrylamide, N-methyl (meth) acrylamide, N-ethyl (meth) acrylamide, N-methoxymethyl (meth) acrylamide, and N-ethoxy. Methyl (meth) acrylamide, N-propoxymethyl (meth) acrylamide, N-butoxymethyl (meth) acrylamide, N-tert-butylacrylamide, N-octylacrylamide, diacetone acrylamide and the like can be used.

  As the tertiary amino group-containing monomer, dimethylaminoethyl (meth) acrylate, diethylaminoethyl (meth) acrylate, dimethylaminopropyl (meth) acrylamide and the like can be used.

  Among monomers having various functional groups as a copolymer component, a carboxyl group-containing monomer, or a carboxyl group-containing monomer and a hydroxyl group-containing monomer is an acrylic copolymer ( A) is preferably included.

  The proportion in which the carboxyl group-containing monomer is included as a copolymer component is included in the acrylic copolymer (A) for the purpose of increasing the cohesive force of the pressure-sensitive adhesive and improving the durability of the pressure-sensitive adhesive composition. On the other hand, it is 0.5% by weight or more, preferably 1% by weight or more. The proportion of the carboxyl group-containing monomer as a copolymer component is 5% by weight with respect to the acrylic copolymer (A) for the purpose of suppressing the adhesive force of the pressure-sensitive adhesive composition from becoming too high. % Or less, preferably 3% by weight or less.

  The proportion of the hydroxyl group-containing monomer as a copolymer component is 0.001% by weight or more with respect to the acrylic copolymer (A) for the purpose of suppressing white spots, preferably 0.8. 01 wt% or more. Further, the proportion of the hydroxyl group-containing monomer as a copolymer component is 1% by weight or less, preferably 0.5% by weight or less for the purpose of suppressing the occurrence of peeling in the durability test.

  The acrylic copolymer (A) according to the first embodiment co-polymerizes monomers other than the (meth) acrylate monomer within a range not exceeding the definition of the acrylic copolymer (A). It can be contained as a coalescing component. As monomers other than the (meth) acrylic acid ester monomer, for example, saturated fatty acid vinyl ester, aromatic vinyl ester, vinyl cyanide monomer, maleic acid or fumaric acid diester can be used. Examples of saturated fatty acid vinyl esters include vinyl formate, vinyl acetate, vinyl propionate, “vinyl versatate” (trade name) and the like (preferably vinyl acetate); and aromatic vinyl monomers such as styrene. , Α-methylstyrene, vinyltoluene, etc .; Examples of vinyl cyanide monomers include acrylonitrile and methacrylonitrile; Examples of maleic acid or fumaric acid diesters include dimethyl maleate and di-N-butyl maleate. Di-2-ethylhexyl maleate, di-N-octyl maleate, dimethyl fumarate, di-N-butyl fumarate, di-2-ethylhexyl maleate, di-N-octyl fumarate, etc. be able to.

  The weight average molecular weight (Mw) of the acrylic copolymer (A) according to the first embodiment gives a sufficient cohesive force to the pressure-sensitive adhesive composition, and is intended to suppress the generation of bubbles. Above, preferably 1 million or more, particularly preferably 1.4 million or more. In addition, the weight average molecular weight (Mw) of the acrylic copolymer (A) is set to 2.5 million or less for the purpose of ensuring the coating workability of the pressure-sensitive adhesive composition.

The weight average molecular weight (Mw) of the acrylic copolymer is a value measured by the following method.
(Measurement method of weight average molecular weight (Mw))
It measures according to following (1)-(3).
(1) An acrylic copolymer solution is applied to release paper and dried at 100 ° C. for 2 minutes to obtain a film-like acrylic copolymer.
(2) The film-like acrylic copolymer obtained in (1) is dissolved in tetrahydrofuran so that the solid content is 0.2%.
(3) Under the following conditions, the weight average molecular weight (Mw) of the acrylic copolymer is measured using gel permeation chromatography (GPC).
(conditions)
GPC: HLC-8220 GPC [manufactured by Tosoh Corporation]
Column: 4 TSK-GEL GMHXL used Mobile phase solvent: Tetrahydrofuran Flow rate: 0.6 ml / min Column temperature: 40 ° C

  The glass transition temperature (Tg) of the acrylic copolymer (A) according to the first embodiment is for the purpose of imparting sufficient cohesive force to the pressure-sensitive adhesive composition and exhibiting sufficient durability. 80 ° C. or higher, preferably −60 ° C. or higher. In addition, the glass transition temperature (Tg) of the acrylic copolymer (A) is sufficient for the adhesive composition to exhibit sufficient adhesion to the support substrate, and for the purpose of exhibiting durability that does not cause peeling. -20 ° C or lower, preferably -40 ° C or lower.

The glass transition temperature (Tg) of the acrylic copolymer is a value obtained by converting the temperature (K) obtained by the calculation of the following formula 1 into (° C.).
Formula 1 1 / Tg = M1 / Tg1 + M2 / Tg2 + M3 / Tg3 + ... + Mn / Tgn
In the formula, Tg1, Tg2, Tg3,..., And Tgn represent the glass transition temperatures (K) of the homopolymers of Component 1, Component 2, Component 3,. Moreover, in formula, M1, M2, M3 ... and Mn show the mole fraction of various components.

  The polymerization method of the acrylic copolymer used in the first embodiment is not particularly limited and can be polymerized by methods such as solution polymerization, emulsion polymerization, suspension polymerization and the like. In producing the pressure-sensitive adhesive composition according to the first embodiment using a mixture of copolymers obtained by polymerization, the polymerization is performed by solution polymerization because the treatment process is relatively simple and can be performed in a short time. It is preferable to do.

  In solution polymerization, a predetermined organic solvent, a monomer, a polymerization initiator, and a chain transfer agent used as needed are generally charged in a polymerization tank, and stirred in a nitrogen stream or at the reflux temperature of the organic solvent. However, a method such as heating reaction for several hours can be used. The weight average molecular weight of the acrylic copolymer (A) according to the first embodiment can be set to a desired molecular weight by adjusting the reaction temperature, time, amount of solvent, type and amount of catalyst. it can.

  The pressure-sensitive adhesive composition according to the first embodiment contains an isocyanate compound (B). Examples of the isocyanate compound (B) include aromatic isocyanates such as xylylene diisocyanate, diphenylmethane diisocyanate, triphenylmethane triisocyanate, and tolylene diisocyanate; for example, hexamethylene diisocyanate, isophorone diisocyanate, and hydrogenated products of the aromatic isocyanate compound. Isocyanate compounds derived from various isocyanates such as aliphatic or alicyclic isocyanates such as dimer or trimer of these isocyanates or adducts of these isocyanates and polyols such as trimethylolpropane can be used. These can be used alone or in combination.

  The isocyanate compound (B) is, for example, “Coronate L”, “Coronate HX”, “Coronate HL-S”, “Coronate 2234” (manufactured by Nippon Polyurethane Industry Co., Ltd.), “Desmodur N3400” [Sumitomo Bayer Urethane ( "Duranate E-405-80T", "Duranate TSE-100" (manufactured by Asahi Kasei Corporation), "Takenate D-110N", "Takenate D-120N", "Takenate M-631N" [ Commercially available products such as “Mitsui Takeda Chemical Co., Ltd.” and the like can be suitably used.

  Among these, as the isocyanate compound (B), an isocyanate compound derived from an aromatic isocyanate is preferable from the viewpoint of durability and whiteness, and an isocyanate compound derived from tolylene diisocyanate is particularly preferable.

  The amount of the isocyanate compound (B) used relative to 100 parts by weight of the acrylic copolymer (A) is 5 parts by weight or more for the purpose of suppressing white spots. Moreover, the usage-amount of the isocyanate compound (B) with respect to 100 weight part of acrylic copolymers (A) ensures compatibility of an acrylic copolymer (A) and an isocyanate compound (B), and is enough as an adhesive. For the purpose of generating tackiness, the amount is 30 parts by weight or less, preferably 20 parts by weight or less, particularly preferably 15 parts by weight or less.

  The pressure-sensitive adhesive composition according to the first embodiment forms a multimer by reacting the isocyanate group of the isocyanate compound (B) that does not contribute to crosslinking with the copolymer with water in the environment. It is thought that there is. Reactivity between isocyanate groups and water is relatively high, and some isocyanate groups react with water in the environment to form multimers without adding an excessive amount of isocyanate groups relative to the reactive functional groups of the resin. However, for the purpose of forming a large number of multimers in order to suppress white spots and improve durability, the total amount of reactive functional groups of the acrylic copolymer (A) is 1 equivalent. More than 1 equivalent, preferably 1.2 equivalents or more, particularly preferably 1.5 equivalents or more of isocyanate groups are used.

  The pressure-sensitive adhesive composition according to the first embodiment can be used in combination with a crosslinking agent other than the isocyanate compound (B). The crosslinking agent other than the isocyanate compound (B) is not particularly limited as long as it reacts with the acrylic copolymer (A) to form a crosslinked structure, and is not limited to an aziridine compound, an epoxy compound, or a melamine formaldehyde. A condensate, a metal salt, a metal chelate compound, etc. can be mentioned. These crosslinking agents other than the isocyanate compound (B) can be used alone or in combination of two or more. In the first embodiment, it is preferable to use an aziridine compound and / or an epoxy compound as a crosslinking agent other than the isocyanate compound (B).

  As the aziridine compound, a reaction product of an isocyanate compound and ethyleneimine can be used, and as the isocyanate compound, those exemplified above can be used. Further, a compound obtained by adding ethyleneimine to a polyvalent ester of a polyol such as trimethylolpropane or pentaerythritol and (meth) acrylic acid is also known and can be used.

  Examples of the aziridine compound include N, N′-hexamethylenebis (1-aziridinecarboxamide), methylenebis [N- (1-aziridinylcarbonyl))-4-aniline], tetramethylolmethane-tris (β- Aziridinylpropionate), trimethylolpropane-tris (β-aziridinylpropionate) and the like. Among these, for example, “TAZO”, “TAZM” [above Mutual Pharmaceutical Co., Ltd. Made by a trade name such as “Chemite PZ-33” (manufactured by Nippon Shokubai Co., Ltd.) can be suitably used.

  Examples of the epoxy compound include ethylene glycol diglycidyl ether, diethylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, propylene glycol diglycidyl ether, tripropylene glycol diglycidyl ether, polypropylene glycol diglycidyl ether, neopentyl glycol diglycidyl ether, 1 , 6-hexanediol diglycidyl ether, polytetramethylene glycol diglycidyl ether, glycerol diglycidyl ether, glycerol triglycidyl ether, diglycerol polyglycidyl ether, polyglycerol polyglycidyl ether, resorcin diglycidyl ether, 2,2-dibromoneo Pentyl glycol diglycidyl ether , Trimethylolpropane triglycidyl ether, pentaerythritol polyglycidyl ether, sorbitol polyglycidyl ether, adipic acid diglycidyl ester, phthalic acid diglycidyl ester, tris (glycidyl) isocyanurate, tris (glycidoxyethyl) isocyanurate, 1, 3-bis (N, N-glycidylaminomethyl) cyclohexane, N, N, N ′, N′-tetraglycidyl-m-xylylenediamine and the like can be used.

  Of the epoxy compounds, an epoxy compound containing three or more epoxy groups is preferable, among which tris (glycidyl) isocyanurate, tris (glycidoxyethyl) isocyanurate, 1,3-bis (N, N-glycidylaminomethyl). ) The use of epoxy compounds such as cyclohexane, N, N, N ′, N′-tetraglycidyl-m-xylylenediamine is more preferred, and 1,3-bis (N, N-glycidylaminomethyl) cyclohexane, N, N The use of N, N ′, N′-tetraglycidyl-m-xylylenediamine is particularly preferred. As such an epoxy compound, for example, those commercially available under trade names such as “TETRAD-C” and “TETRAD-X” (manufactured by Mitsubishi Gas Chemical Co., Inc.) can be suitably used.

  The pressure-sensitive adhesive composition according to the first embodiment contains a zirconium compound (C). Examples of the zirconium compound (C) include tetraalkoxyzirconiums such as zirconium tetranormal propoxide and zirconium tetranormal butoxide, zirconium tetraacetylacetonate, zirconium tributoxymonoacetylacetonate, zirconium monobutoxyacetylacetonate bis (ethyl). Acetoacetate), zirconium dibutoxybis (ethylacetoacetate), zirconium chelates such as zirconium tetraacetylacetonate, zirconium acylates and the like can be used. Of these, zirconium chelates are preferable because of a good balance between pot life and reaction rate, and zirconium chelates having two ligands are particularly preferable.

  Zirconium compounds (C) are, for example, “Orgachix ZC-150”, “Orgachix ZC-540”, “Orgachix ZC-570”, “Orgachix ZC-580”, “Olgatix ZC-700” [Matsumoto A product commercially available under a trade name such as “Fine Chemical Co., Ltd.” can be preferably used.

  The amount of the zirconium compound (C) used relative to 100 parts by weight of the acrylic copolymer (A) is 0.001 part by weight or more, preferably 0.01 part by weight or more for the purpose of shortening the curing time. The amount of the zirconium compound (C) used relative to 100 parts by weight of the acrylic copolymer (A) is 0.1 parts by weight or less, preferably 0.05 parts by weight for the purpose of securing a sufficient pot life. Below.

  The pressure-sensitive adhesive composition according to the first embodiment contains a chelating agent (D). As a chelating agent (D), (beta) -diketone, (beta) -ketoester etc. can be used, for example. Specific examples of β-diketones and β-ketoesters include acetylacetone, methyl acetoacetate, ethyl acetoacetate, acetoacetate-n-propyl, and acetoacetate-i-propyl. Of these, acetylacetone is preferred because of a good balance between pot life and reaction rate. By using such a chelating agent (D), β-diketones and β-ketoesters are coordinated to zirconium of the zirconium compound, so that the pot life can be extended.

  The amount of the chelating agent (D) used is 50 times or more, preferably 100 times or more the weight of the zirconium compound (C) for the purpose of securing a sufficient pot life. Moreover, the upper limit of the amount of the chelating agent (D) used is not particularly limited, but less than 500 weight is appropriate from the economical aspect.

  The pressure-sensitive adhesive composition of the present invention can further use a silane coupling agent. Examples of such silane coupling agents include organic substitution such as mercapto group-containing silicone alkoxy oligomers, epoxy group-containing silicone alkoxy oligomers, amino group-containing silicone alkoxy oligomers, phenyl group-containing silicone alkoxy oligomers, and methyl group-containing silicone alkoxy oligomers. Group-containing silicone alkoxy oligomers; mercapto group-containing silane coupling agents such as γ-mercaptopropyltrimethoxysilane, γ-mercaptopropyltriethoxysilane, γ-mercaptopropyldimethoxymethylsilane; for example, β- (3,4-epoxy Cyclohexyl) ethyltrimethoxysilane, β- (3,4-epoxycyclohexyl) ethyltriethoxysilane, and other alicyclic epoxy group-containing silanes Coupling agents; for example, epoxy group-containing silane coupling agents such as methyltri (glycidyl) silane, γ-glycidoxypropylmethyldimethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropyltriethoxysilane For example, 3-triethoxysilylpropyl succinic acid (anhydride), 3-trimethoxysilylpropyl succinic acid (anhydride), 3-methyldimethoxysilylpropyl succinic acid (anhydride), methyldiethoxysilylpropyl succinic acid ( Anhydride), carboxyl group-containing silane coupling agents such as 1-carboxy-3-triethoxysilylpropyl succinic acid (anhydride); for example, N- (β-aminoethyl) -γ-aminopropylmethyldimethoxysilane, N -(Β-aminoethyl) -γ-aminopro Rutrimethoxysilane, N- (β-aminoethyl) -γ-aminopropyltriethoxysilane, γ-aminopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, N-phenyl-γ-aminopropyltrimethoxysilane, etc. Amino group-containing silane coupling agent; For example, hydroxyl group-containing silane coupling agent such as γ-hydroxypropyltrimethoxysilane; For example, amide group-containing silane compound such as γ-amidopropyltrimethoxysilane; Isocyanurate bones such as tris (3-trimethoxysilylpropyl) isocyanurate, tris (3-triethoxysilylpropyl) isocyanurate; isocyanate group-containing silane coupling agents such as propyltrimethoxysilane And the like can be used containing silane coupling agent. Use of a silane coupling agent is preferable for improving durability.

  The amount of the silane coupling agent used relative to 100 parts by weight of the acrylic copolymer (A) is 0.01 parts by weight or more and 3 parts by weight or less, preferably 0 for the purpose of improving the durability of the pressure-sensitive adhesive composition. .01 part by weight or more and 2 parts by weight or less, particularly preferably 0.02 part by weight or more and 1 part by weight or less.

  The pressure-sensitive adhesive composition according to the first embodiment includes the acrylic copolymer (A) and the isocyanate compound (B), a crosslinking agent other than the isocyanate compound, a zirconium compound (C), a chelating agent (D), In addition to the silane coupling agent, various additives, solvents, tackifiers, weathering stabilizers, plasticizers in amounts that do not impair the effects exhibited by the pressure-sensitive adhesive composition according to the first embodiment. , Softeners, dyes, pigments, inorganic fillers and the like can be appropriately blended.

  The range of the blending amount of the weather resistance stabilizer, tackifier, plasticizer, softener, dye, pigment, inorganic filler, etc. is preferably 30 parts by weight or less with respect to 100 parts by weight of the acrylic copolymer (A). More preferably, it is 20 parts by weight or less, and most preferably 10 parts by weight or less. By setting the blending amount within the range, the pressure-sensitive adhesive composition can maintain an appropriate balance of adhesive strength, wettability, heat resistance, paste transferability, and exhibit various physical properties. can get.

  In the pressure-sensitive adhesive composition according to the first embodiment, the reactive functional group of the acrylic copolymer (A) and the isocyanate compound (B) form a crosslinked structure, and the isocyanate group that did not contribute to the crosslinking reaction It is thought to form multimers by reacting with water in the environment. The gel content after the formation of the crosslinked structure and the multimer is 30% by weight or more, preferably 40% by weight or more, particularly preferably 50% by weight or more for the purpose of suppressing foaming in durability evaluation. is there. Further, the gel content after the formation of the crosslinked structure and the multimer is 95% by weight or less for the purpose of suppressing the occurrence of peeling in the durability evaluation.

The gel content can be measured by the following method.
(Measurement of gel content of adhesive composition)
It measures according to following (1)-(6).
(1) A solution of the pressure-sensitive adhesive composition was applied to a release sheet surface-treated with a silicone release agent so that the coating amount after drying was 25 g / m 2 and dried at 100 ° C. for 90 seconds with hot air circulation Dry with a machine to form a film-like pressure-sensitive adhesive layer.
(2) The formed pressure-sensitive adhesive layer is cured at 35 ° C. and humidity 45% RH for 4 days.
(3) Apply about 0.25 g of the film-like pressure-sensitive adhesive layer obtained in (2) to a precisely weighed 250-mesh wire mesh (100 mm × 100 mm) and wrap so that the gel content does not leak. Thereafter, the weight is accurately measured with a precision balance to prepare a sample.
(4) The wire mesh is immersed in an ethyl acetate solution for 3 days.
(5) After immersion, the wire mesh is taken out, washed with a small amount of ethyl acetate, and dried at 120 ° C. for 24 hours. Thereafter, the weight is accurately measured with a precision balance.
(6) The gel content is calculated by the following formula.
Gel content (% by weight) = (C−A) / (B−A) × 100
However, A is the weight (g) of the wire mesh, B is the weight of the wire mesh (adhesive weight) (g), and C is the weight of the wire mesh (gel resin weight) (g) dried after immersion. is there.

(Optical film)
FIG. 1 shows an outline of a cross section of an optical film according to the present embodiment, and FIG. 2 shows an outline of a cross section of an optical film according to a modification of the embodiment.

  The optical film which concerns on 1st Embodiment is an optical film which has the adhesive layer formed from the adhesive composition which concerns on 1st Embodiment. The specific manufacturing method forms an adhesive layer on a release sheet by applying and drying the adhesive composition according to the first embodiment on the release sheet. Then, the pressure-sensitive adhesive layer formed on the release sheet can be transferred to an optical film and then cured. Here, as the optical film, an optical film used for production of various display devices and the like can be used, and the type thereof is not particularly limited. For example, a polarizing film, a retardation film, a brightness enhancement film, or an antiglare film is used. Includes sheets. The optical film has two layers of optical materials, such as a laminate of a polarizing film and a retardation film, a laminate of a retardation film, and a laminate of a polarizing film and a brightness enhancement film or an antiglare sheet. It can also have the form which laminated | stacked above.

  For example, as shown in FIG. 1, the optical film according to the first embodiment is provided with a release sheet 4 and an adhesive layer that is provided on the release sheet 4 and is made of the adhesive composition according to the first embodiment. 3, an optical film material 2 provided on the adhesive layer 3, and a protective film 1 provided on the optical film material 2. Moreover, as shown in FIG. 2, the optical film which concerns on the modification of 1st Embodiment is provided on the peeling sheet 4 and the peeling sheet 4, and is the adhesive which consists of an adhesive composition which concerns on this Embodiment. Layer 3, optical film material 2 provided on adhesive layer 3, adhesive layer 5 further provided on optical film material 2, optical film material 6 provided on adhesive layer 5, and optical film material 6 And a protective film 1 provided thereon.

  As the release sheet, a synthetic resin sheet such as polyester subjected to release treatment with a release agent such as fluorine resin, paraffin wax, or silicone can be used. The thickness of the pressure-sensitive adhesive layer formed on the release sheet is, for example, 1 μm or more and 100 μm or less, preferably 5 μm or more and 50 μm or less, more preferably 15 μm or more and 30 μm or less in terms of the thickness after drying.

  The pressure-sensitive adhesive composition applied on the release sheet can be dried with a hot air dryer under heating conditions of 70 to 120 ° C. for about 1 to 3 minutes.

  The adhesive strength of the optical film comprising the pressure-sensitive adhesive composition according to the first embodiment and the pressure-sensitive adhesive layer made of this pressure-sensitive adhesive composition is the reactive functional group of the acrylic copolymer (A), By adjusting the type and amount of the isocyanate compound (B) and the like, the desired adhesive strength can be adjusted.

(Liquid crystal display device)
FIG. 3 shows an outline of a cross section of the liquid crystal display device according to the present embodiment, and FIG. 4 shows an outline of a cross section of the liquid crystal display device according to a modification of the embodiment.

  The liquid crystal display device according to the first embodiment is a liquid crystal display device including the optical film according to the first embodiment. In addition, the liquid crystal display device can be manufactured by sticking the optical film according to the first embodiment to one side or both sides of the liquid crystal cell via the adhesive layer of the optical film. For example, as shown in FIG. 3, the liquid crystal display device includes an optical film material 2 including a polarizing film 21 and a reflective layer 22 on one surface of the liquid crystal cell 5 via the adhesive layer 3 according to the first embodiment. Is bonded, and the polarizing film 21 is bonded to the other surface of the liquid crystal cell 5 via the adhesive layer 3. The liquid crystal cell 5 has a configuration in which the liquid crystal layer 50 is sandwiched between predetermined substrates 52. Furthermore, as shown in FIG. 4, another liquid crystal display device includes an optical film material 2 in which a polarizing film 21 and a reflective layer 22 are bonded via an adhesive layer 3 on one side and the other side of a liquid crystal cell. Each of these is manufactured by being bonded via the adhesive layer 3 according to the present embodiment. In the bonding, the polarizing film, the retardation film, and the like are performed so as to be in a predetermined arrangement position, and the arrangement position can be based on the conventional one. As the liquid crystal cell of the liquid crystal display device, for example, a liquid crystal cell of TN type, STN type, π type, or the like can be appropriately employed.

(Effects of the first embodiment)
Since the optical film including the pressure-sensitive adhesive composition according to the first embodiment and the pressure-sensitive adhesive layer made of the pressure-sensitive adhesive composition has the above-described configuration, the curing period is short while having a sufficient pot life, and acrylic. It is generated by reacting with water in the curing environment an isocyanate group that does not contribute to the cross-linking reaction of the isocyanate compound (B) and the chemical cross-linking by the reaction of the reactive functional group of the copolymer (A) with the cross-linking agent. It is considered that the polymer has a high cohesion due to the formation of a multimer as a reactant and physical crosslinking that restricts the movement of the molecular chain of the acrylic copolymer. The physical cross-linking part that restrains the movement is considered to be excellent in stress relaxation because of its fluidity, and can have both durability and white spot suppression at a high level.

  That is, in the pressure-sensitive adhesive composition according to the first embodiment, an amount of isocyanate compound in which the equivalent of the isocyanate group of the isocyanate compound (B) is larger than the equivalent of the reactive functional group of the acrylic copolymer (A). Since (B) is used, not only chemical crosslinking by reaction of the reactive functional group of the acrylic copolymer (A) with the crosslinking agent, but also of the isocyanate compound (B) added to the acrylic copolymer (A) Among them, a multimer derived from the isocyanate compound (B) having an isocyanate group that has not reacted with the acrylic copolymer (A) is produced. Thereby, the pressure-sensitive adhesive composition according to the first embodiment has an entangled structure of molecular chains generated by chemical cross-linking by the reaction between the reactive functional group of the acrylic copolymer (A) and the cross-linking agent. A multimer of the isocyanate compound (B) exists. Therefore, in the pressure-sensitive adhesive composition according to the first embodiment, the multimer is unevenly dispersed in the entangled structure of the molecular chain generated by the chemical crosslinking by the reaction between the reactive functional group and the crosslinking agent, For example, durability and suppression of white spots can be realized at a high level while ensuring good transparency to visible light.

[Second Embodiment]
(Mixed adhesive composition)
The pressure-sensitive adhesive composition according to the second embodiment contains a reactive functional group that is different from the acrylic copolymer (A) containing a reactive functional group and the acrylic copolymer (A). An acrylic copolymer (E), an isocyanate compound (B), a zirconium compound (C), and a chelating agent (D) are contained. That is, the pressure-sensitive adhesive composition according to the second embodiment has substantially the same configuration as the pressure-sensitive adhesive composition according to the first embodiment except that the pressure-sensitive adhesive composition further contains an acrylic copolymer (E). . Therefore, a detailed description is omitted except for differences. In the pressure-sensitive adhesive composition according to the second embodiment, the reactive functional group of the acrylic copolymer (A) and acrylic copolymer (E) and the isocyanate compound (B) undergo a crosslinking reaction. In addition, a multimer as a reaction product formed by reacting the isocyanate group of the isocyanate compound (B) that did not contribute to the crosslinking reaction among the isocyanate compound (B) with water in the environment, thereby forming a good It is considered to have adhesive properties.

  In the second embodiment, among the monomers having various functional groups as the copolymer component, in particular, the carboxyl group-containing monomer is included in the acrylic copolymer (A) as the copolymer component. It is preferable.

  In the second embodiment, the acrylic copolymer (E) has a (meth) acrylic acid ester monomer as a main component as a copolymer component in the copolymer, and a (meth) acrylic acid ester. And a copolymer obtained by copolymerizing a monomer having a reactive functional group, which is different from the acrylic copolymer (A). The pressure-sensitive adhesive composition according to the second embodiment uses a mixture of an acrylic copolymer (A) and an acrylic copolymer (E) as a resin component, so that cohesive force and stress relaxation properties are obtained. It can be adjusted with good balance.

  The copolymer component of the acrylic copolymer (E) according to the second embodiment includes (meth) acrylic acid ester, a monomer having a reactive functional group, and an acrylic monomer as another monomer. A copolymer component similar to the copolymer component exemplified for the copolymer (A) can be used.

  Among monomers having various reactive functional groups as a copolymer component, a carboxyl group-containing monomer and a hydroxyl group-containing monomer are included in the acrylic copolymer (E) as a copolymer component. Is preferred. When the acrylic copolymer (E) contains a carboxyl group-containing monomer and a hydroxyl group-containing monomer, the acrylic copolymer (E) has a high cohesive force and easily adjusts the cohesive force and stress relaxation property of the resin component. An acrylic copolymer (E) that can be obtained can be realized.

  The proportion of the carboxyl group-containing monomer as a copolymer component increases the cohesive strength of the pressure-sensitive adhesive, and improves the durability of the pressure-sensitive adhesive composition, in the acrylic copolymer (E). On the other hand, it is 0.1% by weight or more, preferably 0.3% by weight or more, particularly preferably 0.5% by weight or more. The proportion of the carboxyl group-containing monomer as a copolymer component is 5% by weight with respect to the acrylic copolymer (E) for the purpose of suppressing the adhesive force of the pressure-sensitive adhesive composition from becoming too high. % Or less, preferably 3% by weight or less, particularly preferably 2% by weight or less.

  The proportion of the hydroxyl group-containing monomer as a copolymer component is 0.01% by weight or more, preferably 0.8%, based on the acrylic copolymer (E) for the purpose of suppressing white spots. It is 1% by weight or more, more preferably 0.3% by weight or more. The proportion of the hydroxyl group-containing monomer as a copolymer component is 5% by weight or less, preferably 3% by weight or less, particularly preferably 1 for the purpose of suppressing the occurrence of peeling in the durability test. Less than wt%.

  The weight average molecular weight (Mw) of the acrylic copolymer (E) according to the second embodiment is 600,000 or more, preferably 1,000,000 or more for the purpose of giving sufficient cohesive force to the pressure-sensitive adhesive composition. Especially preferably, it should be 1.4 million or more. Further, the weight average molecular weight (Mw) of the acrylic copolymer (E) is set to 2.5 million or less for the purpose of ensuring the coating workability of the pressure-sensitive adhesive composition.

  The glass transition temperature (Tg) of the acrylic copolymer (E) according to the second embodiment is equal to the glass transition temperature of the acrylic copolymer (A) or the acrylic copolymer (A). It is preferably higher than the glass transition temperature. If the Tg of the acrylic copolymer (A) and the Tg of the acrylic copolymer (E) are in the above relationship, the acrylic copolymer (E) is more cohesive than the acrylic copolymer (A). It is easy to balance the cohesive strength of the resin component and the stress relaxation property. More specifically, the glass transition temperature of the acrylic copolymer (E) is preferably −60 ° C. or more for the purpose of giving the adhesive composition sufficient cohesive force and exhibiting sufficient durability. Is -50 ° C or higher. The glass transition temperature of the acrylic copolymer (E) is 0 ° C. or less for the purpose of exhibiting sufficient adhesiveness to the support substrate in the pressure-sensitive adhesive composition and exhibiting durability that does not cause peeling. The temperature is preferably -30 ° C or lower.

  Moreover, the polymerization method of the acrylic copolymer (E) used for 2nd Embodiment is not restrict | limited in particular, It can superpose | polymerize by the method similar to an acrylic copolymer (A). In producing the pressure-sensitive adhesive composition according to the second embodiment using a mixture of copolymers obtained by polymerization, polymerization is performed by solution polymerization because the treatment process is relatively simple and can be performed in a short time. It is preferable to do. The solution polymerization can employ the same method as in the first embodiment. The weight average molecular weight of the acrylic copolymer (E) according to the second embodiment is also set to a desired molecular weight by adjusting the reaction temperature, time, amount of solvent, type and amount of catalyst. Can do.

The difference between the solubility parameter of the solubility parameter of the acrylic copolymer _(A) (SP A) and acrylic copolymer _{(E) (SP B) (} ΔSP = SP A -SP B) is -0.5 It is preferably 0.5 or more, more preferably −0.4 or more and 0.4 or less, and particularly preferably −0.2 or more and 0.2 or less. A difference in solubility parameter (ΔSP) within the above range is preferable because the compatibility between the acrylic copolymer (A) and the acrylic copolymer (E) is extremely excellent.

Solubility parameters are calculated by the method of Fedor. The Fedor method is described, for example, in “SP Value Basics / Applications and Calculation Methods” (Hideki Yamamoto, published by Information Technology Corporation, 2005). In the Fedor method, the solubility parameter is calculated from the following equation 2.
Formula 2 Solubility parameter = √ (ΣEcoh / ΣV)
In Equation 2, Ecoh is the cohesive energy density and V is the molar molecular volume. Based on Ecoh and V determined for each atomic group, the solubility parameter can be calculated by obtaining the total ΣEcoh and ΣV of Ecoh and V in the repeating unit of the polymer. The solubility parameter of the copolymer is calculated by calculating the solubility parameter of each homopolymer of each constituent unit constituting the copolymer according to the above formula 2, and the mole value of each constituent unit is calculated for each of these SP values. Calculated by adding the product of the fractions.

  The mixing ratio of the acrylic copolymer (A) and the acrylic copolymer (E) is a weight ratio (acrylic copolymer (A) for the purpose of suppressing the occurrence of peeling in the durability test. ) / Weight of acrylic copolymer (E)) is 50/50 or more, preferably 70/30 or more, particularly preferably 80/20 or more. The ratio of mixing the acrylic copolymer (A) and the acrylic copolymer (E) is a weight ratio (acrylic copolymer) for the purpose of suppressing the occurrence of foaming in the durability test. 99/1 or less, preferably 95/5 or less, and particularly preferably 90/10 or less in terms of (weight of (A) / weight of acrylic copolymer (E)).

  And the adhesive composition which concerns on 2nd Embodiment contains an isocyanate compound (B). As the isocyanate compound (B), the same compound as in the first embodiment is used.

  In the second embodiment, the use amount of the isocyanate compound (B) with respect to 100 parts by weight of the mixture of the acrylic copolymer (A) and the acrylic copolymer (E) is to suppress white spots. For the purpose of 5 parts by weight or more. Moreover, the usage-amount of the isocyanate compound (B) with respect to 100 weight part of the mixture of an acrylic copolymer (A) and an acrylic copolymer (E) is compatible with a copolymer and an isocyanate compound (B). For the purpose of securing and generating sufficient tackiness as an adhesive, the amount is 30 parts by weight or less, preferably 20 parts by weight or less, and particularly preferably 15 parts by weight or less.

  Also in the pressure-sensitive adhesive composition according to the second embodiment, the isocyanate of the isocyanate compound (B) that does not contribute to crosslinking with the copolymer as in the pressure-sensitive adhesive composition according to the first embodiment. The group is considered to form multimers by reacting with water in the environment. In the second embodiment, the acrylic copolymer (A) and the acrylic copolymer (()) are formed for the purpose of forming many multimers in order to suppress white spots and improve durability. More than 1 equivalent, preferably 1.01 equivalents or more, particularly preferably 1.2 equivalents or more of isocyanate groups are used with respect to a total of 1 equivalent of reactive functional groups with E).

  The pressure-sensitive adhesive composition according to the second embodiment contains a zirconium compound (C). As the zirconium compound (C), the same compound as in the first embodiment is used.

  In 2nd Embodiment, the usage-amount of a zirconium compound (C) with respect to 100 weight part of mixtures of acrylic copolymer (A) and acrylic copolymer (E) shortens curing time. For the purpose, it is 0.001 part by weight or more, preferably 0.01 part by weight or more. The amount of the zirconium compound (C) used relative to 100 parts by weight of the mixture of the acrylic copolymer (A) and the acrylic copolymer (E) is 0. 1 part by weight or less, preferably 0.05 part by weight or less.

  The pressure-sensitive adhesive composition according to the second embodiment contains a chelating agent (D). As the chelating agent (D), the same compound as in the first embodiment is used.

  The amount of the chelating agent (D) used is 50 times or more, preferably 100 times or more the weight of the zirconium compound (C) for the purpose of securing a sufficient pot life. Moreover, the upper limit of the amount of the chelating agent (D) used is not particularly limited, but less than 500 weight is appropriate from the economical aspect.

  Moreover, the usage-amount of the silane coupling agent with respect to 100 weight part of the mixture of an acrylic copolymer (A) and an acrylic copolymer (E) aims at improving the durability of an adhesive composition, 0.01 part by weight or more and 3 parts by weight or less, preferably 0.01 part by weight or more and 2 parts by weight or less, particularly preferably 0.02 part by weight or more and 1 part by weight or less. Furthermore, the pressure-sensitive adhesive composition according to the second embodiment includes the above-mentioned acrylic copolymer (A), acrylic copolymer (E), isocyanate compound (B), and a crosslink other than the isocyanate compound. In addition to the agent and the silane coupling agent, various additives in an amount within the range not impairing the effects exhibited by the pressure-sensitive adhesive composition according to the second embodiment, as in the first embodiment. Etc. can be suitably blended.

  Furthermore, in the pressure-sensitive adhesive composition according to the second embodiment, the reactive functional group of the acrylic copolymer (A) and the acrylic copolymer (E) and the isocyanate compound (B) form a crosslinked structure. However, it is considered that the isocyanate group that did not contribute to the crosslinking reaction reacts with water in the environment to form a multimer. The gel content after the formation of the crosslinked structure and the multimer is 30% by weight or more, preferably 40% by weight or more, particularly preferably 50% by weight or more for the purpose of suppressing foaming in durability evaluation. is there. Moreover, the gel content after the cross-linked structure and the multimer are formed is 95% by weight or less for the purpose of suppressing the occurrence of peeling in the durability evaluation.

(Effect of the second embodiment)
Since the optical film comprising the pressure-sensitive adhesive composition according to the second embodiment and the pressure-sensitive adhesive layer made of this pressure-sensitive adhesive composition has the above-described configuration, the curing period is short while having a sufficient pot life, and acrylic. Is a chemical crosslinking by the reaction of the reactive functional group of the acrylic copolymer (A) and the acrylic copolymer (E) and the crosslinking agent, and the isocyanate group that does not contribute to the crosslinking reaction of the isocyanate compound (B) in the curing environment. It is considered durable because it forms a multimer as a reaction product generated by reacting with certain water and has a high cohesion due to physical crosslinking that restrains the movement of the molecular chain of the acrylic copolymer. The physical cross-linking part that restricts the movement of the molecular chain is also fluid and therefore considered to be excellent in stress relaxation, and has a high level of durability and suppression of white spots. be able to

  That is, in the pressure-sensitive adhesive composition according to the second embodiment, the isocyanate group of the isocyanate compound (B) is determined from the equivalent of the reactive functional group of the acrylic copolymer (A) and the acrylic copolymer (E). Since the isocyanate compound (B) is used in such an amount that the equivalent of is increased, not only the chemical crosslinking by the reaction of the reactive functional group of the acrylic copolymer (A) and the acrylic copolymer (E) with the crosslinking agent. Of the isocyanate compound (B) added to the acrylic copolymer (A) and the acrylic copolymer (E), it does not react with the acrylic copolymer (A) and the acrylic copolymer (E). A multimer derived from the isocyanate compound (B) having an isocyanate group is produced. Thereby, the pressure-sensitive adhesive composition according to the second embodiment is generated by chemical crosslinking by the reaction of the reactive functional group of the acrylic copolymer (A) and the acrylic copolymer (E) with the crosslinking agent. In the entangled structure of the molecular chain, a multimer of the isocyanate compound (B) is present. Therefore, in the pressure-sensitive adhesive composition according to the first embodiment, the multimer is unevenly dispersed in the entangled structure of the molecular chain generated by the chemical crosslinking by the reaction between the reactive functional group and the crosslinking agent, For example, durability and suppression of white spots can be realized at a high level while ensuring good transparency to visible light.

  Examples and comparative examples will be described below. In addition, preparation of the test piece used in the Example and the comparative example, various test methods, and an evaluation method are as follows.

(1) Preparation of optical film for test A polarizing film having an adhesive layer was prepared using a polarizing film as an example of the optical film. The pressure-sensitive adhesive composition was applied on a release film surface-treated with a silicone release agent so that the coating amount after drying was 25 g / cm ² . Next, it was dried with a hot air circulation dryer at 100 ° C. for 90 seconds to form an adhesive layer. Subsequently, the pressure-sensitive adhesive layer surface is bonded to the back surface of a polarizing base film (a cellulose triacetate (TAC) film laminated on both sides of a polarizer mainly composed of a polyvinyl alcohol (PVA) film; about 190 μm), and then applied to a pressure nip roll. Crimped through. After pressure bonding, the film was cured at 35 ° C. and 45% RH for 4 days to obtain a polarizing film having an adhesive layer.

(2) Durability Evaluation A test of 140 mm × 260 mm (long side) obtained by cutting the polarizing film prepared in “(1) Preparation of optical film for test” so that the long side is 45 ° with respect to the absorption axis. A piece was used and attached to one side of a 0.7 mm Corning non-alkali glass plate “# 1737” using a laminator. Next, this sample was subjected to autoclaving (50 ° C., 5 kg / cm ² , 20 minutes), and allowed to stand for 24 hours at 23 ° C. and 65% RH. Thereafter, the sample was left for 1000 hours in an environment of 80 ° C. DRY and 60 ° C. and 90% RH, and the state of foaming, peeling and floating was evaluated by visual observation. The evaluation criteria are as follows.

(Durability evaluation criteria)
a) Foaming ◯: Foaming is not seen at all Δ: Foaming is hardly seen ×: Foaming is noticeable

b) Peeling ◎: No peeling on 4 sides.
◯: No peeling at a position of 0.3 mm or more from the outer peripheral edge on 4 sides.
X: One of the four sides is peeled off at a position of 0.3 mm or more from the outer peripheral end.

(3) Polarized film having a pressure-sensitive adhesive layer of the same size as “(2) Evaluation of durability” on both sides of 0.7 mm Corning non-alkali glass plate “# 1737” A test sample was prepared in which the polarized light having the agent layer was stuck so that the polarization axes thereof were orthogonal to each other. Next, this sample was subjected to autoclaving (50 ° C., 5 kg / cm ² , 20 minutes), and allowed to stand for 24 hours at 23 ° C. and 65% RH. Then, it was left to stand at 80 ° C. under dry conditions for 500 hours. After standing, a uniform light source was used under the conditions of 23 ° C. and 65% RH, and the white spot state was visually inspected. The evaluation criteria are as follows.
(Outline evaluation criteria)
A: No white spots are observed.
○: Almost no white spots are observed.
X: White spots are large.

(4) Pot Life Evaluation Test The pressure-sensitive adhesive composition was diluted with methyl ethyl ketone so that the viscosity at 25 ° C. was 1800 to 2000 mPa · s to obtain a pressure-sensitive adhesive composition solution. Then, the obtained pressure-sensitive adhesive composition solution is stored at 23 ° C. and stored until the coating film formed by applying the pressure-sensitive adhesive composition solution can be uniformly coated without causing cloudiness and uneven coating. Confirmed the time. The evaluation criteria are as follows. In addition, a coating composition is an adhesive composition so that the coating amount after drying may be 25 g / cm < ² > on the peeling film surface-treated with the silicone type release agent. Was applied and dried with a hot air circulation dryer at 100 ° C. for 90 seconds.

(Pot life evaluation criteria)
◎: 48 hours or more ○: 24 hours or more and less than 48 hours ×: Less than 24 hours

(5) Measurement of curing time Except changing the curing period to 35 ° C, humidity 45% RH for 2 days, 3 days, 4 days, 5 days (measurement of gel content of adhesive composition) The gel content was measured in the same manner as above. The required curing time was defined as the number of days in which the difference between the current gel and the next gel was within 1% of the current gel.

(Manufacture of acrylic copolymer)
(Production Example 1)
In a reactor equipped with a thermometer, a stirrer, a nitrogen introduction tube, and a reflux condenser, 99 parts by weight of n-butyl acrylate (BA), 1 part by weight of acrylic acid (AA), 100 parts by weight of ethyl acetate (EAc), And 0.1 part by weight of azobisisobutyronitrile (AIBN) were added, and the air in the reaction vessel was replaced with nitrogen gas. Thereafter, the temperature of the contents of the reaction vessel was raised to 65 ° C. and reacted for 8 hours in a nitrogen atmosphere under stirring. After completion of the reaction, the reaction mixture was diluted with ethyl acetate to obtain an acrylic copolymer solution having a solid content of 16.8% by weight. The weight average molecular weight of the acrylic copolymer was 1,670,000.

(Production Examples 2-3)
Instead of the copolymer composition used in Production Example 1, polymerization was carried out in the same manner as in Production Example 1 except that the copolymer composition was changed to the monomer composition shown in each production example in Table 1. Table 1 shows the copolymer composition, solid content, glass transition point (Tg), solubility parameter (SP value), and weight average molecular weight (Mw) of each production example.

(Production of acetylacetone solution of zirconium dibutoxybis (ethylacetoacetate))
ORGATICS ZC-580 [Matsumoto Fine Chemical Co., Ltd .: active ingredient (zirconium dibutoxybis (ethylacetoacetate) 70%] 99 parts by weight of acetylacetone was added to 1 part by weight, and zirconium dibutoxybis (ethylacetoacetate) was added. A zirconium complex solution containing 0.7% by weight was prepared.

(Production of acetylacetone solution of dibutyltin dilaurate)
99 parts by weight of acetylacetone was added to 1 part by weight of dibutyltin dilaurate to prepare an organic tin solution containing 1% by weight of dibutyltin dilaurate.

(Production of pressure-sensitive adhesive composition for polarizing plate)
Example 1
506 parts by weight (85 parts by weight as the acrylic copolymer (A)) of the acrylic copolymer solution synthesized in Production Example 1 as the acrylic copolymer (A), manufactured as the acrylic copolymer (E) 76 parts by weight of the acrylic copolymer solution synthesized in Example 2 (15 parts by weight as the acrylic copolymer (E)) and 18.7 parts by weight of Coronate L as the isocyanate compound (B) (isocyanate compound manufactured by Nippon Polyurethane Co., Ltd.) 14 parts by weight of active ingredient), 0.02 part by weight of TETRAD-X as an epoxy compound (epoxy compound manufactured by Mitsubishi Gas Chemical Company, 0.2 part by weight of active ingredient), and 5.7 parts by weight of the zirconium complex solution (active ingredient) (0.04 parts by weight of zirconium dibutoxybis (ethyl acetoacetate)), 0.1 weight of KBM-403 as a silane coupling agent Part (Shin-Etsu Chemical Co., Ltd. silane coupling agent, active ingredient 0.1 parts by weight) was sufficiently stirred and mixed to obtain an adhesive composition. The amount of isocyanate group (described as “NCO / resin functional group” in Table 2) with respect to 1 equivalent total of reactive functional groups of the acrylic copolymer (A) and the acrylic copolymer (E) is 4.02. Equivalent. Using the obtained pressure-sensitive adhesive composition, a test was performed by the above-described gel content measurement method, pot life evaluation test, and curing time measurement, and the results are shown in Table 2. Furthermore, using the obtained pressure-sensitive adhesive composition, a test optical film was prepared by the above-described test optical film preparation method, the above-described various measurements were performed, and the results are shown in Table 3.

(Examples 2-3, Comparative Example 1)
A pressure-sensitive adhesive composition (adhesives according to Examples 2 to 3) was used in the same manner as in Example 1 except that the compounding compositions of Examples and Comparative Examples shown in Table 2 were used instead of the compounding compositions in Example 1. Adhesive composition and a pressure-sensitive adhesive composition according to Comparative Example 1). Using the obtained pressure-sensitive adhesive composition, a test was performed by the above-described gel content measurement method, pot life evaluation test, and curing time measurement, and the results are shown in Table 2. Furthermore, using the obtained pressure-sensitive adhesive composition, a test optical film was prepared by the above-described test optical film preparation method, the above-described various measurements were performed, and the results are shown in Table 3.

(Comparative Example 2)
A pressure-sensitive adhesive composition according to Comparative Example 2 was prepared in the same manner as in Example 1 except that the organotin solution was used in place of the zirconium complex solution in Example 1 and the formulation shown in Table 2 was adopted. Using the obtained pressure-sensitive adhesive composition, a test was performed by the above-described gel content measurement method, pot life evaluation test, and curing time measurement, and the results are shown in Table 2. Furthermore, using the obtained pressure-sensitive adhesive composition, a test optical film was prepared by the above-described test optical film preparation method, the above-described various measurements were performed, and the results are shown in Table 3.

  In Table 2, “NCO / resin functional group” represents the amount of isocyanate group relative to a total of 1 equivalent of reactive functional groups of the acrylic copolymer in each formulation composition example.

In addition, the symbol of each compound in Table 2 is as follows, and the addition amount of each component is a weight part of an active ingredient.
(A) Coronate L “Isocyanate compound manufactured by Nippon Polyurethane Co., Ltd.”
Product name: Coronate L, 75% active ingredient
Trimethylolpropane modified tolylene diisocyanate isocyanate compound (B) component (b) TETRAD-X "Epoxy compound manufactured by Mitsubishi Gas Chemical Company"
Product name: TETRAD-X, 100% by weight of active ingredient
Chemical name: N, N, N ′, N′-tetraglycidyl-m-xylenediamine epoxy compound (c) zirconium complex “Orgatyx ZC-580 [manufactured by Matsumoto Fine Chemical Co., Ltd .: active ingredient (zirconium dibutoxybis (ethyl) Acetoacetate)) 70%] acetylacetone solution ", active ingredient 0.7%
(D) Organotin "acetylbutylacetone solution of dibutyltin dilaurate", active ingredient 1%
(E) KBM-403 “Silane coupling agent manufactured by Shin-Etsu Chemical Co., Ltd.”
Product name: KBM-403, 100% active ingredient
Chemical name; 3-glycidoxypropyltrimethoxysilane,
Silane coupling agent component

  As can be seen by referring to Table 2, all the pressure-sensitive adhesive compositions according to Examples 1 to 3 had a sufficient pot life of 48 hours or more and a short required curing time of 3 days. Further, as can be seen from Table 3, all optical films according to Examples 1 to 3 are evaluated in all items of durability (80 ° C.), durability (60 ° C. × 90% RH), and white spots. The standard indicated “◎” or “◯”. That is, the pressure-sensitive adhesive composition and the optical film according to Examples 1 to 3 have a sufficient pot life, and are excellent in productivity because of a short curing time, and also excellent in durability under a high temperature or high temperature and high humidity environment. It was also shown that white spots can be suppressed.

  In addition, the optical film having the adhesive for optical film according to the present embodiment and the examples is excellent in suppressing white spots, and does not generate peeling or bubbles that normally occur at high temperature or high temperature and high humidity. The present invention can be applied to optical films used in display devices such as computers, televisions, and car navigation systems.

  As mentioned above, although embodiment and the Example of this invention were described, embodiment described above and an Example do not limit the invention which concerns on a claim. In addition, it should be noted that not all combinations of the features described in the embodiments and examples are essential to the means for solving the problems of the invention.

DESCRIPTION OF SYMBOLS 1 Protective film 2 Optical film material 3 Adhesive layer 4 Release sheet 5 Adhesive layer 6 Optical film material

21 Polarizing film 22 Reflecting layer

50 Liquid crystal layer 52 Substrate

Claims (11)

An acrylic copolymer (A) containing a reactive functional group;
5 parts by weight or more and 30 parts by weight or less of the isocyanate compound (B) added to 100 parts by weight of the acrylic copolymer (A);
A zirconium compound (C);
A pressure-sensitive adhesive composition comprising a chelating agent (D). 0.001 part by weight or more and 0.1 part by weight or less of a zirconium compound (C) added to 100 parts by weight of the acrylic copolymer (A);
The pressure-sensitive adhesive composition according to claim 1, comprising a chelating agent (D) to be added in an amount of 50 times or more based on the weight of the zirconium compound (C).   The acrylic copolymer (A) contains a carboxyl group-containing monomer having a carboxyl group as the reactive functional group in an amount of 0.5 wt% to 5 wt% as a copolymer component. Or the adhesive composition of 2.   The acrylic copolymer (E) further contains an acrylic copolymer (E) containing a reactive functional group, which is different from the acrylic copolymer (A), and the isocyanate compound (B) includes the acrylic copolymer (A) and The pressure-sensitive adhesive composition according to claim 1, which is added to 100 parts by weight of the mixture with the acrylic copolymer (E).   The zirconium compound (C) and the chelating agent (D) are added to 100 parts by weight of a mixture of the acrylic copolymer (A) and the acrylic copolymer (E). Adhesive composition. The acrylic copolymer (A) contains 0.5% by weight or more and 5% by weight or less of a carboxyl group-containing monomer containing a carboxyl group as the reactive functional group as a copolymer component,
The acrylic copolymer (E) has a carboxyl group-containing monomer containing a carboxyl group as the reactive functional group in an amount of 0.1% by weight to 5% by weight and a hydroxyl group as the reactive functional group. The pressure-sensitive adhesive composition according to claim 4 or 5, which contains as a copolymer component 0.01 to 5% by weight of a hydroxyl group-containing monomer.   The said acrylic copolymer (A) and the said acrylic copolymer (E) are contained in the weight ratio of 50/50 or more and 99/1 or less of any one of Claims 4-6. Adhesive composition.   The pressure-sensitive adhesive composition according to any one of claims 1 to 7, wherein the zirconium compound (C) is a zirconium complex having two ligands.   The pressure-sensitive adhesive composition according to any one of claims 1 to 8, wherein the chelating agent (D) is acetylacetone.   The optical film which has an adhesive layer formed from the adhesive composition of any one of Claims 1-9. A liquid crystal display device comprising the optical film according to claim 10.