JP5923231B2 - Adhesive composition, optical film, and method for producing adhesive composition - Google Patents

Description

  The present invention relates to a pressure-sensitive adhesive composition for an optical film, an optical film with a pressure-sensitive adhesive, and a pressure-sensitive adhesive composition used for adhering an optical film such as a polarizing film or a retardation film to an adherend such as a liquid crystal cell. The present invention relates to a method for manufacturing a product. More specifically, the present invention provides an optical film pressure-sensitive adhesive composition, an optical film with pressure-sensitive adhesive, and the pressure-sensitive adhesive composition, which have excellent durability even under high temperature and high humidity, and have characteristics that hardly cause white spots. The present invention relates to a method for manufacturing a product.

  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 turns white.

  In order to improve such a problem, an adhesive having stress relaxation properties by adding a low molecular weight polymer to the adhesive composition has been proposed. For example, Patent Document 1 (Japanese Patent Application Laid-Open No. 10-279907) discloses a polarization comprising a high molecular weight acrylic copolymer, a low molecular weight acrylic copolymer having a weight average molecular weight of 30,000 or less, and a polyfunctional compound. A pressure-sensitive adhesive composition for a plate is disclosed, and it is described that the pressure-sensitive adhesive composition follows a dimensional change of a polarizing plate and hardly causes white spots. However, in the pressure-sensitive adhesive composition described in Patent Document 1, it is difficult to prevent foaming and peeling under high temperature and high humidity because the amount of the low molecular weight acrylic copolymer having a weight average molecular weight of 30,000 or less is large.

  Patent Document 2 (Japanese Patent Laid-Open No. 2006-133606) discloses a low glass transition temperature (Tg) acrylic copolymer having a functional group-containing monomer of 0.5% by weight or less and a functional group-containing monomer. A pressure-sensitive adhesive composition having a gel fraction of less than 30% by weight comprising a mixture of a high Tg acrylic copolymer having a body of 6% by weight or more, a crosslinking agent capable of reacting with a functional group and an isocyanate compound is disclosed. . This pressure-sensitive adhesive composition exhibits a cohesive force by forming a cross-linked structure in the molecule of a high Tg acrylic copolymer and constraining the molecules of the low Tg acrylic copolymer with a multimer of isocyanate compounds. Yes. However, this pressure-sensitive adhesive composition has little cross-linking structure between molecules, so white spots are hardly generated. However, the cohesive force at low temperatures is low, and it is difficult to suppress the occurrence of foaming and peeling in durability evaluation. difficult.

  Patent Document 3 (Japanese Patent Laid-Open No. 2004-224873) discloses an adhesive composition in which 0.3 to 3 parts by weight of an isocyanate compound is added to an acrylic copolymer having a carboxyl group and a hydroxyl group. The pressure-sensitive adhesive composition is described as being excellent in durability and suppression of white spots. This pressure-sensitive adhesive composition is excellent in durability and suppression of white spots when used in a small liquid crystal display device as in the examples of the above-mentioned publication. However, when used in a large liquid crystal display device, the durability and the suppression of white spots are inferior, and a pressure-sensitive adhesive composition capable of suppressing white spots at a higher level is required. ing.

  In recent years, with the increase in size of liquid crystal display devices, the size of optical films has also increased. Since dimensional changes such as expansion and contraction of the optical film increase as the size increases, higher durability and suppression of white spots are required. A pressure-sensitive adhesive composition having a high cohesive force is disclosed as a pressure-sensitive adhesive that satisfies durability even when used in a large-screen liquid crystal display device. For example, Patent Document 4 (Japanese Patent Application Laid-Open No. 9-113724) discloses an acrylic copolymer (A) containing a carboxyl group or an amide group and not containing a hydroxyl group, and an acrylic type containing a carboxyl group or an amide group and a hydroxyl group. A polarizing plate pressure-sensitive adhesive composition is disclosed, in which an isocyanate compound is blended with a mixture obtained by mixing the copolymer (B) at a weight ratio of 20/80 to 50/50. However, even though the pressure-sensitive adhesive composition described in Patent Document 4 can suppress foaming and peeling under high temperature and high humidity, white spots are likely to occur due to insufficient stress relaxation properties.

JP-A-10-279907 JP 2006-133606 A JP 2004-224873 A Japanese Patent Laid-Open No. 9-113724

  In the pressure-sensitive adhesive composition according to Patent Documents 1 to 4, as described above, it is difficult to provide an optical film that can achieve both durability and suppression of white spots. For example, the size of optical films used for liquid crystal display devices having a large screen has been increasing in recent years, and as the size increases, the dimensional change of optical films under high temperature and high humidity also increases. Therefore, it is required to suppress durability and white spots. And the optical film which can fully exhibit durability and suppression of whitening is not provided yet.

  Therefore, the present invention aims to achieve both durability and suppression of white spots, and is excellent in durability under high temperature and high humidity even when using a large-sized optical film, and suppresses white spots. It aims at providing the manufacturing method of the adhesive composition for optical films, the said optical film with an adhesive, and the said adhesive composition.

In order to achieve the above object, the present invention provides a pressure-sensitive adhesive composition, an optical film, and a method for producing a pressure-sensitive adhesive composition having the following configurations.
(1) 1% by weight to 3% by weight of a carboxyl group-containing monomer containing a carboxyl group as a reactive functional group, and 0% by weight to 0% of a hydroxyl group-containing monomer containing a hydroxyl group as a reactive functional group 0.05 wt% or less of the acrylic copolymer (A) as a copolymer component, and 10 to 30 parts by weight with respect to 100 parts by weight of the acrylic copolymer (A), and And an adhesive composition for an optical film, which is a component of a liquid crystal display device, comprising an isocyanate compound (B) added so that the equivalent of an isocyanate group to 1.5 equivalents or more relative to 1 equivalent of the reactive functional group is However, this excludes those containing an acrylic polymer having no cross-linked site).
(2) 3 wt% and less carboxyl group-containing monomer 1 wt% or more containing a carboxyl group as reactivity functional group, hydroxyl group-containing monomer 0 wt% or more containing a hydroxyl group as a reactive functional group 0 Different from the acrylic copolymer (A) containing .05% by weight or less as a copolymer component and the acrylic copolymer (A), a carboxyl group containing a carboxyl group as a reactive functional group containing containing a monomer 0.1 wt% to 5 wt% or less, and less hydroxyl group-containing monomer 0.1 wt% to 5 wt% having a hydroxyl group as a reactive functional group as a copolymer component 10 parts by weight to 30 parts by weight with respect to 100 parts by weight of the acrylic copolymer (C) and a mixture of the acrylic copolymer (A) and the acrylic copolymer (C), and Of the reactive functional group Equivalent isocyanate compound is added to a 1.2 or higher (B) and the optical film pressure-sensitive adhesive composition is a component of a liquid crystal display device comprising the isocyanate group to the equivalents.
( 3 ) The component of the liquid crystal display device according to ( 2 ), wherein the weight average molecular weight of each of the acrylic copolymer (A) and the acrylic copolymer (C) is 1 million to 2.5 million. A pressure-sensitive adhesive composition for an optical film.
( 4 ) The above ( 2 ) or ( 3 ), wherein the acrylic copolymer (A) and the acrylic copolymer (C) are contained in a weight ratio of 50/50 or more and 99/1 or less. The adhesive composition for optical films which is a component of the liquid crystal display device .
( 5 ) The glass transition temperature of the acrylic copolymer (C) is equal to the glass transition temperature of the acrylic copolymer (A) or the glass transition temperature of the acrylic copolymer (A). The adhesive composition for optical films which is a component of the liquid crystal display device as described in any one of said ( 2 )-( 4 ) higher than temperature.
( 6 ) Furthermore, the adhesive composition for optical films as described in any one of said (1)-( 5 ) containing an aziridine compound and / or an epoxy compound.
( 7 ) In any one of the above (1) to ( 6 ), including a multimer formed by the reaction of the isocyanate compound (B) having an isocyanate group not reacted with the reactive functional group and water. The adhesive composition for optical films which is a component of the liquid crystal display device of description .
(8 ) A component of a liquid crystal display device having a pressure-sensitive adhesive layer formed from the pressure-sensitive adhesive composition for an optical film, which is a component of the liquid crystal display device according to any one of (1) to ( 7 ) above. An optical film.
( 9 ) 1% by weight or more and 3% by weight or less of a carboxyl group-containing monomer containing a carboxyl group as a reactive functional group, and 0% by weight or more and 0% by weight of a hydroxyl group-containing monomer containing a hydroxyl group as a reactive functional group 0.05 wt% or less of the acrylic copolymer (A) containing as a copolymer component, and an amount of 10 to 30 parts by weight with respect to 100 parts by weight of the acrylic copolymer (A). And the isocyanate compound (B) that undergoes a cross-linking reaction with the reactive functional group of the acrylic copolymer (A). light is a component of a liquid crystal display device for mixing the compound (B) the isocyanate compound in an amount that equivalent increases 1.5 times or more of the isocyanate groups of the (B) in the acrylic copolymer (a) Method for producing a film pressure-sensitive adhesive composition (excluding those containing acrylic polymer having no crosslinking site).

  According to the pressure-sensitive adhesive composition for an optical film, the pressure-sensitive adhesive-coated optical film, and the method for producing the pressure-sensitive adhesive composition according to the present invention, a good balance between cohesive force and stress relaxation properties is achieved. Even under, it is excellent in durability and can suppress white spots.

  As a result of diligent research, the inventors of the present invention have achieved durability by using a pressure-sensitive adhesive composition containing an acrylic copolymer (A) containing a reactive functional group and a specific amount of an isocyanate compound (B). It has been found that a pressure-sensitive adhesive composition (hereinafter sometimes referred to as “single-type pressure-sensitive adhesive composition”) capable of achieving both compatibility and suppression of white spots can be provided. 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). By using a pressure-sensitive adhesive composition obtained by adding a specific amount of an isocyanate compound (C) to a mixture with an acrylic copolymer (C) containing a reactive functional group, both durability and suppression of white spots can be achieved. It has been found that a pressure-sensitive adhesive composition (hereinafter sometimes referred to as “mixed pressure-sensitive adhesive composition”) that can be achieved can be provided.

[First Embodiment]
(Single pressure-sensitive adhesive composition)
The pressure-sensitive adhesive composition according to the first embodiment of the present invention contains an acrylic copolymer (A) containing a reactive functional group and a specific amount of an isocyanate compound (B). 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, preferably 0.8%, based on the acrylic copolymer (A) for the purpose of suppressing white spots. 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 1.2 million or more, particularly preferably 1.4 million or more. Moreover, the weight average molecular weight (Mw) of an acrylic copolymer (A) shall be 2.5 million or less for the purpose of ensuring the coating workability | operativity of an 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 5 to 30 parts by weight of the isocyanate compound (B) with respect to 100 parts by weight of the acrylic copolymer (A).

  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 whitening property, 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 of the present invention can further use a silane compound. Examples of such silane compounds include organic substituents 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. Silicone alkoxy oligomers; mercapto group-containing silane compounds such as γ-mercaptopropyltrimethoxysilane, γ-mercaptopropyltriethoxysilane, γ-mercaptopropyldimethoxymethylsilane; for example, β- (3,4-epoxycyclohexyl) ethyltri Cycloaliphatic epoxy group-containing silane compounds such as methoxysilane and β- (3,4-epoxycyclohexyl) ethyltriethoxysilane; Epoxy group-containing silane compounds such as tiltri (glycidyl) silane, γ-glycidoxypropylmethyldimethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropyltriethoxysilane; for example, 3-triethoxysilyl Propyl succinic acid (anhydride), 3-trimethoxysilylpropyl succinic acid (anhydride), 3-methyldimethoxysilylpropyl succinic acid (anhydride), methyldiethoxysilylpropyl succinic acid (anhydride), 1-carboxy- Carboxyl group-containing silane compounds such as 3-triethoxysilylpropyl succinic acid (anhydride); for example, N- (β-aminoethyl) -γ-aminopropylmethyldimethoxysilane, N- (β-aminoethyl) -γ- Aminopropyltrimethoxysilane, N- (β-aminoethyl Γ-aminopropyltriethoxysilane, γ-aminopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, amino group-containing silane compounds such as N-phenyl-γ-aminopropyltrimethoxysilane; Hydroxyl group-containing silane compounds such as hydroxypropyltrimethoxysilane; for example, amide group-containing silane compounds such as γ-amidopropyltrimethoxysilane; for example, isocyanate group-containing silane compounds such as γ-isocyanatopropyltrimethoxysilane; Isocyanurate skeleton-containing silane compounds such as tris (3-trimethoxysilylpropyl) isocyanurate and tris (3-triethoxysilylpropyl) isocyanurate can be used. Use of a silane compound is preferable for improving durability.

  The amount of the silane compound used relative to 100 parts by weight of the acrylic copolymer (A) is 0.01 to 3 parts by weight, preferably 0.01 to 2 parts by weight for the purpose of improving the durability of the pressure-sensitive adhesive composition. Parts, particularly preferably 0.02 to 1 part by weight.

  The pressure-sensitive adhesive composition according to the first embodiment includes the acrylic copolymer (A) and the isocyanate compound (B), the crosslinking agent other than the isocyanate compound, and the silane compound, as well as the first embodiment. Various additives, solvents, weathering stabilizers, tackifiers, plasticizers, softeners, dyes, pigments, inorganic fillers, etc., as appropriate, in amounts that do not impair the effects exhibited by the PSA composition Can be 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 60% by weight or more, preferably 70% by weight or more, particularly preferably 80% 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 23 ° C. and a humidity of 65% RH for 10 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.

  The pressure-sensitive adhesive composition according to the first embodiment is a step of mixing at least an acrylic copolymer (A) containing a reactive functional group and an isocyanate compound (B) that undergoes a crosslinking reaction with the reactive functional group. It is manufactured through. In this mixing step, the amount of the isocyanate compound (B) 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) is the acrylic copolymer. It is mixed with the polymer (A). Specifically, a step of preparing an acrylic copolymer (A) containing a reactive functional group, a step of preparing an isocyanate compound (B) that undergoes a crosslinking reaction with the reactive functional group, and a prepared acrylic copolymer It is synthesized through a step of mixing the polymer (A) and the prepared isocyanate compound (B). And the process of preparing an isocyanate compound (B) is an isocyanate compound (B) of the quantity which the equivalent of the isocyanate group of an isocyanate compound (B) increases more than the equivalent of the reactive functional group of an acrylic copolymer (A). Prepare.

  Moreover, the optical film which concerns on 1st Embodiment is an optical film which has an 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.

  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 to 100 μm, preferably 5 to 50 μm, more preferably about 15 to 30 μm 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.

(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 reactive functional group of the acrylic copolymer (A) and Chemical cross-linking by the reaction of the cross-linking agent and isocyanate groups that do not contribute to the cross-linking reaction of the isocyanate compound (B) react with moisture in the curing environment to form multimers, and the movement of the molecular chain of the acrylic copolymer It is thought that it has a high cohesive force due to the physical cross-linking that restrains the stress, so the durability is good, and the physical cross-linking part that restrains the movement of the molecular chain is also fluid, so stress relaxation It is also considered to be superior, and can have both durability and suppression of white spots 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 achieved 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 (C) and a specific amount of an isocyanate compound (B) 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 (C). . 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 the acrylic copolymer (C) 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 (C) 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 (C) 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 (C) 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 the monomers having various reactive functional groups as the copolymer component, a carboxyl group-containing monomer and a hydroxyl group-containing monomer are included in the acrylic copolymer (C) as the copolymer component. Is preferred. When the acrylic copolymer (C) contains a carboxyl group-containing monomer and a hydroxyl group-containing monomer, the acrylic copolymer (C) has a high cohesive force and easily adjusts the cohesive force and stress relaxation property of the resin component. An acrylic copolymer (C) that can be obtained can be realized.

  The proportion in which the carboxyl group-containing monomer is contained as a copolymer component is included in the acrylic copolymer (C) 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 0.1% 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 (C) 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. 0% with respect to the acrylic copolymer (C) 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 (C) according to the second embodiment is 1 million or more, preferably 1.2 million or more for the purpose of giving a sufficient cohesive force to the pressure-sensitive adhesive composition. Especially preferably, it should be 1.4 million or more. Moreover, the weight average molecular weight (Mw) of an acrylic copolymer (C) shall be 2.5 million or less for the purpose of ensuring the coating workability | operativity of an adhesive composition.

  The glass transition temperature (Tg) of the acrylic copolymer (C) 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 (C) are in the above relationship, the acrylic copolymer (C) 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 (C) is preferably −60 ° C. or higher for the purpose of giving sufficient cohesive force to the pressure-sensitive adhesive composition and exhibiting sufficient durability. Is -50 ° C or higher. The glass transition temperature of the acrylic copolymer (C) is 0 ° C. or lower 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 (C) 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. And also about the weight average molecular weight of the acryl-type copolymer (C) based on 2nd Embodiment, it is set as desired molecular weight by adjusting reaction temperature, time, the amount of solvent, and the kind and quantity of a catalyst. Can do.

The difference between the solubility parameter of the solubility parameter of the acrylic copolymer _(A) (SP A) and acrylic copolymer _{(C) (SP B) (} ΔSP = SP A -SP B) is -0.5 -0.5 is preferable, -0.4-0.4 is more preferable, and -0.2-0.2 is particularly preferable. A difference in solubility parameter (ΔSP) within the above range is preferable because the compatibility between the acrylic copolymer (A) and the acrylic copolymer (C) 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] ^ 2
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 ratio of mixing the acrylic copolymer (A) and the acrylic copolymer (C) is a weight ratio (acrylic copolymer (A) for the purpose of suppressing the occurrence of peeling in the durability test. ) / Weight of acrylic copolymer (C)) 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 (C) 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, particularly preferably 90/10 or less in terms of (A) weight / acrylic copolymer (C) weight).

  And the adhesive composition which concerns on 2nd Embodiment is 5-30 weight part isocyanate with respect to 100 weight part of the mixture of an acrylic copolymer (A) and an acrylic copolymer (C). Contains compound (B). As the isocyanate compound (B), the same compound as in the first embodiment is used.

  In 2nd Embodiment, the usage-amount of the isocyanate compound (B) with respect to 100 weight part of mixtures of an acrylic copolymer (A) and an acrylic copolymer (C) makes white suppression suppressed. 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 (C) makes compatibility of 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, an acrylic copolymer (A) and an acrylic copolymer (for the purpose of forming many multimers in order to suppress white spots and improve durability. More than 1 equivalent, preferably 1.01 equivalent or more, particularly preferably 1.2 equivalent or more isocyanate group is used per 1 equivalent of the total reactive functional groups with C).

  Moreover, the usage-amount of the silane compound with respect to 100 weight part of the mixture of an acrylic copolymer (A) and an acrylic copolymer (C) is set to 0.00% for the purpose of improving the durability of an adhesive composition. The amount is from 0.1 to 3 parts by weight, preferably from 0.01 to 2 parts by weight, particularly preferably from 0.02 to 1 part by weight. Furthermore, the pressure-sensitive adhesive composition according to the second embodiment includes the above-described acrylic copolymer (A), acrylic copolymer (C), isocyanate compound (B), and crosslinks other than isocyanate compounds. In addition to the agent and the silane compound, in the same amount as in the first embodiment, various additives and the like in an amount that does not impair the effect exhibited by the pressure-sensitive adhesive composition according to the second embodiment. It can mix | blend suitably.

  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 (C) and the isocyanate compound (C) 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 60% by weight or more, preferably 70% by weight or more, particularly preferably 80% by weight or more for the purpose of suppressing the occurrence of 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.

Examples and Comparative Examples will be described below (however, Examples 3 and 5 are reference examples). 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 23 ° C. and 65% RH for 10 days to obtain a polarizing film having an adhesive layer.

(2) Measurement of adhesive strength After the polarizing film prepared in “(1) Preparation of optical film for test” was cut into 25 mm × 150 mm, this polarizing film piece was subjected to a 0.7 mm thickness using a table laminator. A test sample was prepared by pressure-bonding to a non-alkali glass plate “# 1737”. This sample was autoclaved (50 ° C., 5 kg / cm ² , 20 minutes). Next, this sample was allowed to stand for 24 hours under conditions of 23 ° C. and 65% RH, and then the adhesive strength at 180 ° peeling (peeling speed: 300 mm / min) was measured.

(3) Evaluation of durability 140 mm × 260 mm (long side) test in which the polarizing film prepared in “(1) Preparation of optical film for test” was cut so that the long side was 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. Then, it was left for 1000 hours under the following temperature and humidity conditions, 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 ○: Foaming is hardly seen ×: Foaming is noticeable

b) Peeling ◎: No peeling on 4 sides.
◯: No peeling at 4 mm or more from the outer peripheral edge on 4 sides.
X: One of the four sides is peeled off at a position of 0.8 mm or more from the outer peripheral end.

(4) Polarized film having a pressure-sensitive adhesive layer having the same size as “(3) Durability evaluation” on the 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 leaving, a uniform light source was used under the conditions of 23 ° C. and 65% RH, and the white spotted state was visually monitored. The evaluation criteria are as follows.
A: No white spots are observed.
○: Almost no white spots are observed.
X: White spots are large.

(Manufacture of acrylic copolymer)
(Production Example 1)
In a reactor equipped with a thermometer, a stirrer, a nitrogen introduction tube and a reflux condenser, 97 parts by weight of n-butyl acrylate (BA), 3 parts by weight of acrylic acid (AA), 100 parts by weight of ethyl acetate (EAc) and azo Add 0.2 parts by weight of bisisobutyronitrile (AIBN), replace the air in the reaction vessel with nitrogen gas, and then raise the temperature of the reaction vessel to 65 ° C. in a nitrogen atmosphere with stirring. The mixture was allowed to react for 6 hours, and further heated to 70 ° C. for 2 hours. Thereafter, a solution in which 0.4 part by weight of AIBN was dissolved in 20 parts by weight of EAc was added dropwise over 1 hour, and the reaction was further continued for 2 hours. After completion of the reaction, the reaction mixture was diluted with toluene to obtain an acrylic copolymer solution having a solid content of 22.68% by weight and a viscosity of 51400 mPa · s. The weight average molecular weight of the acrylic polymer was 1.72 million.

(Production Example 8)
In the same reactor as in Production Example 1, n-butyl acrylate (BA) 98.975 parts by weight, acrylic acid (AA) 1 part by weight, 2-hydroxyethyl acrylate (2HEA) 0.025 part by weight, ethyl acetate ( EAc) 100 parts by weight and 0.2 parts by weight of azobisisobutyronitrile (AIBN) were added, the air in the reaction vessel was replaced with nitrogen gas, and the contents of the reaction vessel were then stirred in a nitrogen atmosphere. The temperature was raised to 65 ° C. and reacted for 6 hours, and further raised to 70 ° C. and reacted for 2 hours. Thereafter, a solution in which 0.4 part by weight of AIBN was dissolved in 20 parts by weight of EAc was added dropwise over 1 hour, and the reaction was further continued for 2 hours. After completion of the reaction, the reaction mixture was diluted with toluene to obtain an acrylic copolymer solution having a solid content of 19.79% by weight and a viscosity of 12200 mPa · s. The weight average molecular weight of the acrylic polymer was 14.1 million.

(Production Examples 2 to 7 and Production Example 9)
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), weight average molecular weight (Mw), and viscosity (mPa · s) of each production example.

(Production of pressure-sensitive adhesive composition for optical film)
Example 1
As the acrylic copolymer (A), 397 parts by weight of the acrylic copolymer solution synthesized in Production Example 1 (90 parts by weight as the acrylic copolymer (A)) and as the acrylic copolymer (C) 51 parts by weight of the acrylic copolymer solution synthesized in Production Example 5 (10 parts by weight as the acrylic copolymer (C)) and 20.0 parts by weight of Coronate L as the isocyanate compound (B) (manufactured by Nippon Polyurethane Co., Ltd.) Polyisocyanate compound, 15 parts by weight of active ingredient), 0.2 part by weight of tris (3-trimethoxysilylpropyl) isocyanurate as a silane compound (a silane compound manufactured by Shin-Etsu Chemical Co., Ltd., trade name: X-12-965, active ingredient) 0.2 parts by weight) and 0.05 part by weight of 3-glycidoxypropyltrimethoxysilane (a silane compound manufactured by Shin-Etsu Chemical Co., Ltd., trade name KBM-403, available) A pressure-sensitive adhesive composition was obtained by sufficiently stirring and mixing 0.05 parts by weight of the active ingredient. The amount of isocyanate groups relative to a total of 1 equivalent of reactive functional groups of the acrylic copolymer (A) and the acrylic copolymer (C) (Tables 2-1, 2-2, and 2-3 show “NCO Described as “/ resin functional group”) was 1.6 equivalents.

(Example 11)
Further, as the acrylic copolymer (A), 505 parts by weight of the acrylic copolymer solution synthesized in Production Example 1 (100 parts by weight as the acrylic copolymer (A)) and coronate as the isocyanate compound (B) L13.3 parts by weight (polyisocyanate compound manufactured by Nippon Polyurethane Co., Ltd., 10 parts by weight of active ingredient), 0.2 parts by weight of tris (3-trimethoxysilylpropyl) isocyanurate (silane compound manufactured by Shin-Etsu Chemical Co., Ltd.) Trade name X-12-965, active ingredient 0.2 part by weight) and 3-glycidoxypropyltrimethoxysilane 0.05 part by weight (Shin-Etsu Chemical silane compound, trade name KBM-403, active ingredient 0. 05 parts by weight) was sufficiently stirred and mixed to obtain an adhesive composition. The amount of isocyanate group relative to a total of 1 equivalent of reactive functional groups of the acrylic copolymer (A) (described as “NCO / resin functional group” in Tables 2-1, 2-2, and 2-3) is as follows. It was 2.96 equivalents.

(Examples 2 to 10, Examples 12 to 17, Comparative Examples 1 to 6)
Instead of the formulation composition in Example 1, Examples 1 and 11 except for employing the formulation compositions of Examples shown in Table 2-1 and Table 2-2 and Comparative Examples shown in Table 2-3. In the same manner, pressure-sensitive adhesive compositions (pressure-sensitive adhesive compositions according to Examples 2 to 10 and Examples 12 to 17 and pressure-sensitive adhesive compositions according to Comparative Examples 1 to 6) were prepared. Using the obtained pressure-sensitive adhesive composition, a test optical film was prepared by the above-described test optical film preparation method, and the above-described various measurements were performed. The result about an Example is shown to Table 3-1, and Table 3-2, and the result about a comparative example is shown to Table 3-3.

In addition, the symbol of each compound in Table 2-1-Table 2-3 is as follows, and the addition amount of each component is a weight part of an active ingredient.
Coronate L: Tolylene diisocyanate adduct of trimethylolpropane manufactured by Nippon Polyurethane, 75% by weight of active ingredient, isocyanate compound (B)
TMSI: silane compound manufactured by Shin-Etsu Chemical Co., Ltd., trade name: X-12-965, chemical name: tris (3-trimethoxysilylpropyl) isocyanurate, active ingredient 100% by weight, silane compound KBM-403: manufactured by Shin-Etsu Chemical Co., Ltd. Silane compound, trade name: KBM-403, chemical name: 3-glycidoxypropyltrimethoxysilane, 100% by weight of active ingredient, silane compound TETRAD-X: epoxy compound manufactured by Mitsubishi Gas Chemical Company, trade name: TETRAD- X, chemical name: N, N, N ′, N′-tetraglycidyl-m-xylenediamine, active ingredient 100% by weight, epoxy compound TAZM: aziridine compound manufactured by Mutual Yakugyo Co., Ltd., trade name: TAZM, chemical name: Trimethylolpropane-tris (β-aziridinylpropionate), active ingredient 100%, aziridine compound X-41-1805: a silane compound manufactured by Shin-Etsu Chemical Co., Ltd., trade name: X-41-1805, a silicone alkoxy oligomer containing a mercapto group as an organic substituent, a methoxy group and an ethoxy group as an alkoxy group, 100 weights of active ingredients %, Silane compound

  In addition, since the optical film which has the adhesive for optical films which concerns on 1st and 2nd embodiment and an Example has favorable durability, and a white blank is suppressed, a personal computer, a television, car navigation, etc. It can apply to the optical film used for the display apparatus of this.

  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 the combinations of features described in the embodiments and examples are necessary for the means for solving the problems of the invention.

Claims (9)

1% by weight or more and 3% by weight or less of a carboxyl group-containing monomer containing a carboxyl group as a reactive functional group, and 0% by weight or more and 0.05% by weight of a hydroxyl group-containing monomer containing a hydroxyl group as a reactive functional group % Or less acrylic copolymer (A) containing as a copolymer component,
10 parts by weight or more and 30 parts by weight or less with respect to 100 parts by weight of the acrylic copolymer (A) and added so that the equivalent of the isocyanate group to 1 equivalent of the reactive functional group is 1.5 or more. A pressure-sensitive adhesive composition for an optical film, which is a constituent element of a liquid crystal display device comprising the isocyanate compound (B) to be prepared (excluding those containing an acrylic polymer having no crosslinking site). 1% by weight or more and 3% by weight or less of a carboxyl group-containing monomer containing a carboxyl group as a reactive functional group, and 0% by weight or more and 0.05% by weight of a hydroxyl group-containing monomer containing a hydroxyl group as a reactive functional group % Or less acrylic copolymer (A) containing as a copolymer component,
Different from the acrylic copolymer (A), a carboxyl group-containing monomer containing a carboxyl group as a reactive functional group, in an amount of 0.1% by weight to 5% by weight, and a hydroxyl group as a reactive functional group. An acrylic copolymer (C) containing, as a copolymer component, 0.1 to 5% by weight of a hydroxyl group-containing monomer containing,
Isocyanate based on 10 parts by weight to 30 parts by weight and 1 equivalent of the reactive functional group with respect to 100 parts by weight of the mixture of the acrylic copolymer (A) and the acrylic copolymer (C). The adhesive composition for optical films which is a component of a liquid crystal display device containing the isocyanate compound (B) added so that the equivalent of group may be 1.2 or more . The weight average molecular weight of each of the acrylic copolymer (A) and the acrylic copolymer (C) is from 1 million to 2.5 million, for an optical film as a component of the liquid crystal display device according to claim 2 . Adhesive composition. The structure of the liquid crystal display device according to claim 2 or 3 , wherein the acrylic copolymer (A) and the acrylic copolymer (C) are contained in a weight ratio of 50/50 or more and 99/1 or less. The adhesive composition for optical films which is an element . The glass transition temperature of the acrylic copolymer (C) is equal to the glass transition temperature of the acrylic copolymer (A) or higher than the glass transition temperature of the acrylic copolymer (A). component adhesive composition for optical films is a liquid crystal display device according to any one of claims 2-4. Furthermore, the adhesive composition for optical films which is a component of the liquid crystal display device of any one of Claims 1-5 containing an aziridine compound and / or an epoxy compound. The liquid crystal display device according to any one of claims 1 to 6 , comprising a multimer formed by a reaction between the isocyanate compound (B) having an isocyanate group that has not reacted with the reactive functional group and water . The adhesive composition for optical films which is a component . The optical film is a component of a liquid crystal display device having a pressure-sensitive adhesive layer formed from the optical film pressure-sensitive adhesive composition is a component of a liquid crystal display device according to any one of claims 1-7. 1% by weight or more and 3% by weight or less of a carboxyl group-containing monomer containing a carboxyl group as a reactive functional group, and 0% by weight or more and 0.05% by weight of a hydroxyl group-containing monomer containing a hydroxyl group as a reactive functional group % Of the above-mentioned reaction in an amount of 10 to 30 parts by weight with respect to 100 parts by weight of the acrylic copolymer (A) and the acrylic copolymer (A). A step of mixing an isocyanate compound (B) that undergoes a crosslinking reaction with a functional functional group,
In the mixing step, the isocyanate compound in an amount that the equivalent of the isocyanate group of the isocyanate compound (B) is 1.5 times or more larger than the equivalent of the reactive functional group of the acrylic copolymer (A). Production of pressure-sensitive adhesive composition for optical film (excluding those containing an acrylic polymer having no cross-linking site), which is a component of a liquid crystal display device in which B) is mixed with the acrylic copolymer (A) Method.