JP5483981B2 - Adhesive composition and optical film - Google Patents

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. Along with this, there is a need for an adhesive that is excellent in durability even under harsh environments such as high temperature and high humidity, that is, it does not peel off or generate bubbles even after long-term use. Has been. Also, under severe environments such as high-temperature environments and high-humidity environments, optical films have large dimensional changes such as shrinkage and expansion, and stress generated by such dimensional changes cannot be relaxed by the adhesive layer. The residual stress of the optical film becomes non-uniform. 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.

In order to solve such a problem, a pressure-sensitive adhesive having stress relaxation properties by adding a low molecular weight polymer to the pressure-sensitive adhesive composition or using a polymer having a wide molecular weight distribution has been proposed. For example, Patent Document 1 (Japanese Patent Laid-Open No. 2006-77224) discloses an acrylic polymer having a weight average molecular weight of 50,000 to 500,000 and a weight average molecular weight of 1,000,000 to 1,500,000. A pressure-sensitive adhesive using a mixture with an acrylic polymer in which the molecular weight distribution (Mw / Mn) of the resin is 5 or less is disclosed. Patent Document 2 (Japanese Patent Laid-Open No. 2002-341141) discloses an acrylic polymer having a weight average molecular weight of 600,000 to 2,000,000 and a ratio of the weight average molecular weight to the number average molecular weight (Mw / Mn) of 4 or more. A pressure-sensitive adhesive using the above is disclosed. Furthermore, Patent Document 3 (Republished Patent WO 2005/111167) discloses that the content of a component having a weight average molecular weight of 800,000 or more and a molecular weight of 300,000 or less is 25% by mass or more based on the whole acrylic polymer, and has a molecular weight. A pressure-sensitive adhesive composition is disclosed in which the slope of a single regression line fitted to a molecular weight distribution curve of a portion of 300,000 or less is 0 or more, the coefficient of determination is 0.8 or more, and Mw / Mn is 20 or more.

However, as in Patent Document 1, a pressure-sensitive adhesive using a mixture of an acrylic resin having a high weight average molecular weight and a narrow molecular weight distribution and an acrylic resin having a low weight average molecular weight, or Patent Document 2 or 3, A pressure-sensitive adhesive using only a polymer having a high weight average molecular weight and a wide molecular weight distribution has insufficient stress relaxation properties, and it is difficult to suppress the occurrence of white spots.

Moreover, in patent document 2 or 3, durability in an 80 degreeC-90 degreeC environment is examined. However, pressure-sensitive adhesives used in in-vehicle liquid crystal display devices such as car navigation systems are required to have durability that does not cause peeling or foaming even under the harsh environment of a car. Durability at 100 ° C. or higher) is necessary. Furthermore, the use of in-vehicle liquid crystal display devices is not limited to conventional car navigation systems, but has been expanded to use for rear entertainment systems and instrument panels for enjoying movies and games in the rear seats, Along with this, the screen size, which was conventionally about 8 inches, has been increased to 12 inches or more.

As in Patent Document 2 or 3, the pressure-sensitive adhesive using only a polymer having a high weight average molecular weight and a wide molecular weight distribution is insufficient in flexibility, and in a durability test under a high temperature environment of 100 ° C. or higher, peeling occurs. It will occur. Therefore, the pressure-sensitive adhesive composition according to Patent Document 2 or 3 cannot be used for an in-vehicle liquid crystal display device that requires durability under a high temperature environment of 100 ° C. or higher. It was impossible to cope with the increase in the screen size of the device.

As an adhesive composition that can be used for a liquid crystal display device for vehicles, the present inventors have a high weight average molecular weight and an acrylic polymer having a molecular weight distribution having a broad distribution on the low molecular weight side, and a low A pressure-sensitive adhesive composition using a mixture of a weight-average molecular weight and an acrylic polymer having a relatively high glass transition point was proposed (Patent Document 4; Japanese Patent Application No. 2009-189350 (unpublished)). An optical film having a pressure-sensitive adhesive layer formed from such a pressure-sensitive adhesive composition is excellent in durability even in a high-temperature environment of 105 ° C., can suppress the occurrence of white spots, and is used in a vehicle-mounted liquid crystal display device It was possible to cope with the increase in screen size.

The pressure-sensitive adhesive composition used for in-vehicle liquid crystal display devices such as car navigation is more outdoor than the pressure-sensitive adhesive composition used for liquid crystal display devices intended for indoor use such as for personal computers and televisions. Exposed to harsh environments. For this reason, the pressure-sensitive adhesive composition used in the in-vehicle liquid crystal display device is required to have durability in a wide temperature range from low temperature to high temperature, and it peels off from the pressure-sensitive adhesive layer even after repeated cooling and heating. And heat shock resistance is required so that appearance changes such as foaming do not occur. Conventionally, as this heat shock resistance, there has been a demand for heat shock resistance that the adhesive layer does not change in appearance even when -35 ° C. cooling and 70 ° C. heating are repeated. The heat shock resistance when repeated cooling at 45 ° C. and heating at 80 ° C. is required, and the required test conditions are becoming stricter. In the optical film having the pressure-sensitive adhesive layer formed from the pressure-sensitive adhesive composition proposed by the present inventors in Patent Document 4 (Japanese Patent Application No. 2009-189350), the pressure-sensitive adhesive is used in a heat shock resistance test under severe conditions. There were cases where peeling or foaming occurred in the layer.

  On the other hand, in Patent Document 5 (Japanese Patent Laid-Open No. 2007-112839), in order to improve the adhesiveness of the pressure-sensitive adhesive, 0.02 to 2 parts by weight of a peroxide with respect to 100 parts by weight of an acrylic copolymer, A pressure-sensitive adhesive composition comprising 0.02 to 2 parts by weight of an isocyanate-based crosslinking agent and 1 to 40 parts by weight of a tackifying resin having a softening point of 80 ° C. or higher is disclosed. However, Patent Document 5 does not describe white spots and heat shock resistance, and merely having the above configuration is insufficient for suppressing the occurrence of white spots and improving heat shock resistance.

JP 2006-77224 A JP 2002-341141 A Republished patent WO2005 / 111167 Japanese Patent Application No. 2009-189350 (unpublished) JP 2007-112839 A

The present invention has been made in view of the above circumstances, and is excellent in durability under a high temperature environment, heat shock resistance when repeated cooling and heating, and suppression of occurrence of white spots under a high temperature environment. It aims at providing the liquid crystal display device using the adhesive composition for optical films, the optical film which has an adhesive layer formed from the said adhesive composition, and the said optical film with an adhesive.

  In order to achieve the above object, the present invention provides an acrylic polymer (A) having a high weight average molecular weight, a wide molecular weight distribution, and a wide molecular weight distribution on the low molecular weight side, and a low weight average molecular weight. And an acrylic polymer (B) having a relatively high glass transition point, a specific amount of a crosslinking agent (C), and a specific amount of a terpene phenol resin (D) are provided. Is. That is, an adhesive composition, an optical film, and a liquid crystal display device having the following configuration are provided.

(1) It contains a reactive functional group, the weight average molecular weight (Mw) is 1 million to 2.5 million, and the ratio (Mw / Mn) of the weight average molecular weight to the number average molecular weight (Mn) is 9 to 30; The value ((Mw / Mn) / (Mz / Mw)) obtained by dividing (Mw / Mn) by the ratio (Mz / Mw) of the Z average molecular weight (Mz) to the weight average molecular weight is 2 or more, and the glass transition point is − An acrylic polymer (A) having a temperature of 45 ° C. or lower;
An acrylic polymer (B) having a weight average molecular weight (Mw) of 50,000 to 300,000 and a glass transition point of −40 ° C. or more and 5 ° C. or less;
For 100 parts by weight of the mixture of the acrylic polymer (A) and the acrylic polymer (B),
0.01 parts by weight or more and 5 parts by weight or less, a crosslinking agent (C) to be added;
A pressure-sensitive adhesive composition comprising 1 part by weight or more and 40 parts by weight or less and a terpene phenol resin (D) to be added.

(2) The pressure-sensitive adhesive composition according to (1), wherein the acrylic polymer (A) and the acrylic polymer (B) are contained in a weight ratio of 50/50 to 95/5.
(3) The pressure-sensitive adhesive composition according to (1) or (2), further comprising a silane coupling agent (E).
(4) The pressure-sensitive adhesive composition according to any one of (1) to (3), further containing a silicone compound (F).
(5) Any one of said (1)-(4) whose gel part after the crosslinked structure is formed of the adhesive layer formed from an adhesive composition is 30 to 80 weight% 2. The pressure-sensitive adhesive composition according to 1.
(6) An optical film having an adhesive layer formed from the adhesive composition according to any one of (1) to (5).
(7) A liquid crystal display device comprising the optical film according to (6).

  According to the pressure-sensitive adhesive composition and optical film according to the present invention, the pressure-sensitive adhesive composition is excellent in durability and suppression of occurrence of white spots under a severe high temperature environment of 100 ° C. or higher, and excellent in heat shock resistance, An optical film having an adhesive layer formed from the pressure-sensitive adhesive composition and a liquid crystal display device using the optical film with the pressure-sensitive adhesive can be provided.

The pressure-sensitive adhesive composition according to the embodiment of the present invention comprises an acrylic polymer (A) having a specific molecular weight distribution, an acrylic polymer (B), a crosslinking agent (C), and a terpene phenol resin (D). contains.

In the present embodiment, the acrylic polymer (A) is an acrylic acid ester monomer, a methacrylic acid ester monomer (hereinafter referred to as “acrylic” and “methacrylic” as a polymer component in the polymer. (Meth) acryl ”may be used as the main component), and the (meth) acrylic acid ester monomer and the monomer having a reactive functional group may be used together. A copolymer obtained by polymerization. The acrylic polymer (A) means a copolymer containing 80% by weight or more of a (meth) acrylic acid ester monomer, 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.

  As a structural component in the acrylic polymer (A) according to the present embodiment, a monomer having a reactive functional group is used for the purpose of reacting the acrylic polymer (A) and the crosslinking agent (C). Including. In addition, what is a (meth) acrylic acid ester monomer which has a reactive functional group is contained as a copolymer component in the acrylic polymer (A) when defining the acrylic polymer ( Counted as the amount of (meth) acrylate 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.

  Of the monomers having various functional groups as the polymer component, a carboxyl group-containing monomer is preferably included in the acrylic polymer (A) as a copolymer component.

  The proportion of the monomer having a reactive functional group as a copolymer component is an acrylic polymer (A) for the purpose of increasing the cohesive force of the pressure-sensitive adhesive and improving the durability of the pressure-sensitive adhesive composition. ) To 0.5% by weight or more, preferably 0.7% by weight or more. In addition, the ratio of the monomer having a reactive functional group as a copolymer component imparts flexibility to the pressure-sensitive adhesive composition, suppresses white spots, and the adhesive strength of the pressure-sensitive adhesive becomes too high. For the purpose of suppressing this, the amount is 2.5% by weight or less, preferably 2% by weight or less, particularly preferably 1.5% by weight or less based on the acrylic polymer (A).

  The acrylic polymer (A) according to the present embodiment contains a monomer other than the (meth) acrylate monomer as a copolymer component within a range not exceeding the definition of the acrylic polymer (A). can do. 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 acrylic polymer (A) according to the present embodiment has a weight average molecular weight (Mw) of 1 million to 2.5 million, a ratio of the weight average molecular weight to the number average molecular weight (Mw / Mn) of 9 to 30, The value ((Mw / Mn) / (Mz / Mw)) obtained by dividing (Mw / Mn) by the ratio (Mz / Mw) of the Z average molecular weight (Mz) to the weight average molecular weight is 2 or more.

The weight average molecular weight (Mw), number average molecular weight (Mn), and Z average molecular weight (Mz) of the acrylic polymer are the logarithm of the molecular weight of a monodisperse polystyrene standard sample by gel permeation chromatography (GPC) and its elution. It is a value obtained from the relative molecular weight (polystyrene equivalent molecular weight) of an acrylic polymer obtained on the basis of a calibration curve created by approximating time with a cubic equation, and is calculated by the following equations (1) to (3). Is. Although the molecular weight varies depending on the measurement conditions such as the GPC column, the weight average molecular weight (Mw), number average molecular weight (Mn), and Z average molecular weight (Mz) according to the present embodiment were measured according to the GPC measurement conditions of the examples. Defined based on value.
Mw = Σ (Ni · Mi ² ) / Σ (Ni · Mi) (1)
Mn = Σ (Ni · Mi) / Σ (Ni) (2)
Mz = Σ (Ni · Mi ³ ) / Σ (Ni · Mi ² ) (3)
In the above formula, Mi is the molecular weight of the i component, and Ni is the number of i components. Mw / Mn gives information on the distribution on the lower molecular weight side than the weight average molecular weight, and Mz / Mw gives information on the distribution on the higher molecular weight side than the weight average molecular weight. A value ((Mw / Mn) / (Mz / Mw)) obtained by dividing the ratio (Mw / Mn) of the weight average molecular weight to the number average molecular weight by the ratio (Mz / Mw) of the Z average molecular weight (Mz) to the weight average molecular weight. ) Is a value indicating the breadth of the “distribution on the lower molecular weight side than the weight average molecular weight”, and the larger the value, the wider the distribution on the lower molecular weight side.

  That is, Mw / Mn is 9 or more and 30 or less, and (Mw / Mn) / (Mz / Mw) is 2 or more, the acrylic polymer (A) according to the present embodiment has a wide molecular weight distribution, and This indicates that the distribution is wide on the low molecular weight side. Therefore, since the acrylic polymer (A) according to the present embodiment has a molecular weight distribution having a high weight average molecular weight and a wide distribution on the low molecular weight side, the acrylic polymer (A) has both cohesion and flexibility, and is durable. And an adhesive composition excellent in suppression of white spots can be obtained.

The weight average molecular weight (Mw) of the acrylic polymer (A) is preferably 1,000,000 or more for the purpose of giving sufficient cohesive strength to the pressure-sensitive adhesive composition and suppressing the generation and peeling of bubbles in the durability test. Is over 1.5 million. In addition, the weight average molecular weight (Mw) of the acrylic polymer (A) is set to 2.5 million or less for the purpose of ensuring the coating workability of the pressure-sensitive adhesive composition.

  The ratio (Mw / Mn) between the weight average molecular weight and the number average molecular weight of the acrylic polymer (A) is 9 or more for the purpose of imparting stress relaxation to the pressure-sensitive adhesive composition and suppressing the occurrence of white spots, Preferably it is 15 or more. The Mw / Mn of the acrylic polymer (A) is 30 or less, preferably 25 or less for the purpose of giving sufficient cohesive force to the pressure-sensitive adhesive composition.

  A value obtained by dividing the ratio (Mw / Mn) between the weight average molecular weight and the number average molecular weight of the acrylic polymer (A) by the ratio (Mz / Mw) between the Z average molecular weight (Mz) and the weight average molecular weight ((Mw / Mw). Mn) / (Mz / Mw)) is 2 or more, preferably 3 or more, particularly preferably 4 or more for the purpose of imparting stress relaxation to the pressure-sensitive adhesive composition and suppressing the occurrence of white spots. In addition, a value obtained by dividing the ratio (Mw / Mn) between the weight average molecular weight and the number average molecular weight (Mw / Mn) of the acrylic polymer (A) by the ratio (Mz / Mw) between the Z average molecular weight (Mz) and the weight average molecular weight (( Mw / Mn) / (Mz / Mw)) is set to 15 or less, preferably 10 or less for the purpose of giving sufficient cohesive force to the pressure-sensitive adhesive composition.

The glass transition point (Tg _A ) of the acrylic polymer (A) according to the present embodiment causes the adhesive composition to exhibit sufficient adhesion to the support substrate, and exhibits durability that does not cause peeling. For the purpose of -45 ° C or lower, preferably -50 ° C or lower.

The glass transition point (Tg) of the acrylic polymer is a value obtained by converting the temperature (K) obtained by the calculation of the following formula (4) into (° C.).
1 / Tg = M1 / Tg1 + M2 / Tg2 + M3 / Tg3 +... + Mn / Tgn (4)
In the above formula, Tg1, Tg2, Tg3,..., And Tgn represent the glass transition points (K) of the homopolymers of Component 1, Component 2, Component 3,. In the above formula, M1, M2, M3,..., And Mn represent mole fractions of various components.

The solubility parameter (SP _A ) of the acrylic polymer (A) according to the present embodiment maintains compatibility with the acrylic polymer (B) and gives sufficient cohesive force to the pressure-sensitive adhesive composition. For the purpose, 17.7 J ^1/2 / cm ^3/2 or more, preferably 18.2 J ^1/2 / cm ^3/2 or more. Further, the solubility parameter (SP _A ) of the acrylic polymer (A) according to the present embodiment maintains compatibility with the acrylic polymer (B), gives the adhesive composition flexibility, and is durable. 19.0 J ^1/2 / cm ^3/2 or less, preferably 18.8 J ^1/2 / cm ^3/2 or less for the purpose of suppressing the occurrence of peeling or white spots in the property test.

The solubility parameter (SP value) is an index representing the tendency of solubility of a substance. The SP value is measured or calculated by various methods. Brandup,
E. H. Immersut, and E.M. A. It is described in detail in Grulke, “Polymer Handbook, Fourth Edition” (1999).

The SP value of the copolymer is calculated by calculating the SP value of each homopolymer of each constituent unit constituting the copolymer, and multiplying each of these SP values by the mole fraction of each constituent unit. It is calculated by adding together. The SP value of the homopolymer was calculated by the SP value calculation formula of the following formula (5) based on the molecular attractive constant G of the monomer.
SP = dΣG / M (5)
In the above formula, d represents density (g / L), ΣG represents the sum of molecular attractive constants in the molecule, and M represents molecular weight (g / mol).

  The polymerization method of the acrylic polymer used in the present embodiment is not particularly limited, and the polymerization can be performed by a method such as solution polymerization, emulsion polymerization, suspension polymerization. In the production of the pressure-sensitive adhesive composition according to the present embodiment using a polymer mixture obtained by polymerization, it is possible to perform polymerization by solution polymerization because the treatment process is relatively simple and can be performed in a short time. preferable.

  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.

  Examples of the organic solvent include aromatic hydrocarbons such as benzene, toluene, ethylbenzene, N-propylbenzene, t-butylbenzene, o-xylene, m-xylene, p-xylene, tetralin, decalin, and aromatic naphtha. Aliphatic or alicyclic hydrocarbons such as, for example, n-hexane, n-heptane, n-octane, i-octane, n-decane, dipentene, petroleum spirit, petroleum naphtha, turpentine oil; , Esters such as n-butyl acetate, n-amyl acetate, 2-hydroxyethyl acetate, 2-butoxyethyl acetate, 3-methoxybutyl acetate, methyl benzoate; for example, acetone, methyl ethyl ketone, methyl-i-butyl ketone, isophorone , Cyclohexanone, methylcyclohexanone and other ketones; examples For example, glycol ethers such as ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether; for example, methyl alcohol, ethyl alcohol, n-propyl alcohol, i Examples include alcohols such as -propyl alcohol, n-butyl alcohol, i-butyl alcohol, s-butyl alcohol, and t-butyl alcohol. These organic solvents can be used alone or in admixture of two or more.

  Among the organic solvents, when the acrylic polymer (A) is polymerized, it is preferable to use an organic solvent that hardly causes chain transfer during the polymerization reaction, for example, esters and ketones. From the viewpoint of the solubility of A) and the ease of the polymerization reaction, use of ethyl acetate, methyl ethyl ketone, acetone or the like is preferable.

  As the polymerization initiator, it is possible to use organic peroxides, azo compounds and the like that can be used in ordinary solution polymerization.

  Examples of such organic peroxides include di (2-ethylhexyl) peroxydicarbonate, di (4-t-butylcyclohexyl) peroxydicarbonate, di-sec-butylperoxydicarbonate, and t-butyl. Peroxyneodecanoate, t-hexyl peroxypivalate, t-butyl peroxypivalate, dilauroyl peroxide, di-n-octanoyl peroxide, 1,1,3,3-tetramethylbutylperoxy 2-ethylhexanoate, di (4-methylbenzoyl) peroxide, dibenzoyl peroxide, t-butylperoxyisobutyrate, 1,1-di (t-hexylperoxy) cyclohexane, t-butyl hydroper An oxide or the like can be used. Examples of the azo compound include 2,2′-azobis-i-butylnitrile, 2,2′-azobis-2,4-dimethylvaleronitrile, and 2,2′-azobis-4-methoxy-2,4. -Dimethylvaleronitrile etc. can be used.

  Among these polymerization initiators, in the polymerization of the acrylic polymer (A), an azo compound that hardly causes a hydrogen abstraction reaction as an initial polymerization initiator is used, and an organic peroxide having a high initiator efficiency as a late polymerization initiator. Is preferably used. In this way, by using different polymerization initiators in the initial stage and the late stage, it is possible to suitably synthesize an acrylic polymer (A) having a high weight average molecular weight and a molecular weight distribution having a wide distribution on the low molecular weight side. Can do.

The pressure-sensitive adhesive composition according to the present embodiment includes an acrylic polymer (B) together with the acrylic polymer (A).

The acrylic polymer (B) according to the present embodiment has a (meth) acrylic acid ester monomer as a main component and a (meth) acrylic acid ester monomer as a polymer component in the polymer. Polymerized polymer. The acrylic polymer (B) means a polymer containing 50% by weight or more of (meth) acrylic acid ester monomer, and a polymer containing 60% by weight or more is preferable.

  The polymer component or copolymer component of the acrylic polymer (B) is not particularly limited as long as the glass transition point of the polymer is −40 ° C. or higher and 5 ° C. or lower. (Meth) acrylic acid ester, reactivity As the monomer having a functional group and the other monomer, a polymer component similar to the polymer component exemplified in the acrylic polymer (A) can be used.

Especially, it is preferable that the monomer of the following (b1)-(b3) is contained in an acrylic polymer (B) among the monomers as a copolymer component of an acrylic polymer (B).
(B1) A monomer having a linear or branched alkyl acrylate monomer having 4 to 10 carbon atoms and a homopolymer having a glass transition point (Tg) of −50 ° C. or lower.
(B2) The copolymerizability with the monomer (b1) is relatively small, preferably the copolymerizability ratio [1 / γ _{(b2 / b1)} ] with the monomer (b1) is less than 0.5 Monomer.
(B3) A monomer having a relatively large copolymerizability with the monomer (b1), preferably having a copolymerizability ratio [1 / γ _{(b3 / b1)} ] of 0.5 or more.
The copolymerization ratio here is the reciprocal (1 / γ) of the reactivity ratio γ in the Lewis-Mayo formula of the monomer copolymerization theory.

In general, the reactivity ratio of monomer A to monomer B is determined by the growth reaction rate constant k _{pAA in} which monomers A are chain-bonded to each other, and the growth reaction rate in which monomer A and monomer B are chain-bonded. It is expressed as a value (k _pAA / k _pAB ) divided by a constant k _pAB . Therefore, the monomer ( _b2 ) having a copolymerization ratio [1 / γ _{(b2 / b1)} ] of less than 0.5 with the monomer (b1) is [1 / γ _{(b2 / b1)} ] = It is a monomer satisfying [kp _{(b1) (b2)} / kp _{(b2) (b2)} ] <0.5.

  For details on the Lewis-Mayo formula, refer to, for example, Shinzo Omi, “Operation design of radical polymerization reaction” (published by IPC Co., Ltd.), page 73 and after.

The glass transition point of the acrylic polymer (B) is −40 ° C. or more and 5 ° C. or less, and the polymer having such a glass transition point is, for example, copolymerizing butyl acrylate (BA) and methyl methacrylate (MMA). Can be obtained. However, when BA and MMA are copolymerized, due to the poor copolymerization between BA and MMA, a hard copolymer with a large amount of MMA is produced first, and then the remaining BA component A very soft copolymer with a lot of content tends to be formed. In the pressure-sensitive adhesive composition using such a copolymer, the extremely soft copolymer is likely to bleed, and rework work (when the optical film is stuck to the adherend, there is a problem such as biting of foreign matter etc. When this occurs, the adherend tends to be contaminated in the operation of peeling and removing the optical film from the adherend and reattaching a new optical film.

Therefore, when the acrylic polymer (B) is polymerized, MMA is used as a monomer that imparts hardness to a monomer that forms a very flexible polymer such as BA.
, N-butyl methacrylate (n-BMA), ethyl methacrylate (EMA), and the like are copolymerizable with BA, etc., while using a small monomer, the remaining BA is polymerized in a form close to a single, In order not to make a soft copolymer, it is preferable to use a monomer copolymerizable with BA or the like, for example, methyl acrylate (MA).

As the monomer (b1), for example, n-butyl acrylate, 2-ethylhexyl acrylate, n-octyl acrylate, i-octyl acrylate, n-nonyl acrylate, i-nonyl acrylate and the like can be used. As the monomer (b1), the difference between the solubility parameter (SP _B ) of the acrylic polymer ( _B ) and the solubility parameter (SP _A ) of the acrylic polymer (A) (ΔSP = SP _B − From the viewpoint of easily reducing SP _A ), n-butyl acrylate is preferable.

  The amount of the monomer (b1) used is appropriately selected so as to satisfy the glass transition point range depending on the type of the monomer (b1) and the types of the monomers (b2) and (b3). However, generally 10 to 90% by weight, preferably 20 to 85% by weight, more preferably based on 100% by weight of the total of the monomers (b1) to (b3) constituting the acrylic polymer (B). Is 25 to 75% by weight, particularly preferably 30 to 65% by weight.

The monomer (b2) is a monomer having a relatively small copolymerizability with the monomer (b1), preferably a monomer having a copolymerizability ratio [1 / γ _{(b2 / b1)} ] of less than 0.5. It is a mer.

When the monomer (b1) is n-butyl acrylate (BA), the monomer having a copolymerizability ratio [1 / γ _{(b2 / b1)} ] with the monomer _{(b1) of} less than 0.5 Examples of (b2) include methacrylic acid esters such as methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, n-butyl methacrylate, i-butyl methacrylate, and t-butyl methacrylate; for example, carboxyl groups such as acrylic acid and methacrylic acid. Containing monomer; For example, a hydroxyl group-containing monomer such as 2-hydroxyethyl acrylate and 2-hydroxyethyl methacrylate can be used. When the monomer (b1) is n-butyl acrylate (BA), the monomer (b2) includes methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, n-butyl methacrylate, i-butyl methacrylate, t- It is preferable to use a methacrylic acid ester having no functional group such as butyl methacrylate.

When the monomer (b1) is other than BA, the copolymerization ratio [1 / γ _{(b2 / b1)} ] between the desired monomer and the monomer (b1) is, for example, Brandrup, E .; H. Immergut,
and E.E. A. Grulke, “Polymer Handbook 4th Edition” (Polymer Handbook,
(Fourth Edition) "(1999), the copolymerization ratio [1 / γ _{(b2 / b1)} ] is less than 0.5 among these monomers. These monomers may be appropriately selected and used as the monomer (b2).

  The amount of the monomer (b2) used is appropriately selected according to the type of the monomer (b2) and the types of the monomer (b1) and the monomer (b3). Generally, an acrylic polymer is used. Based on a total of 100% by weight of the monomers (b1) to (b3) constituting (B), 5 to 85% by weight, preferably 10 to 75% by weight, more preferably 15 to 65% by weight, particularly preferably Is 20 to 55% by weight. It is preferable that the amount of the monomer (b2) used is equal to or greater than the lower limit value because the cohesive strength of the pressure-sensitive adhesive composition is sufficient, foaming hardly occurs in the durability test, and reworkability is good. Moreover, if the usage-amount of a monomer (b2) is below an upper limit, since the adhesive composition can exhibit sufficient adhesiveness with respect to a support substrate, and durability which does not produce peeling etc. can be exhibited, it is preferable. .

The monomer (b3) has a relatively high copolymerizability with the monomer (b1), and preferably has a copolymerization ratio [1 / γ _{(b3 / b1)} ] of 0.5.
The above monomers, that is, monomers satisfying [1 / γ _{(b3 / b1)} ] = [kp _{(b1) (b3)} / kp _{(b3) (b3)} ] ≧ 0.5 It is.

When the monomer (b1) is BA, the copolymerization ratio [1 / γ _{(b3 / b1)} ] with the monomer (b1) is 0.5.
Examples of the monomer (b3) include acrylic acid esters such as methyl acrylate and ethyl acrylate; for example, saturated fatty acid vinyl esters such as vinyl formate, vinyl acetate, and vinyl propionate; and amide groups such as acrylamide. Monomers can be used. When the monomer (b1) is BA, it is preferable to use an acrylate ester having no functional group such as methyl acrylate or ethyl acrylate as the monomer (b3).

When the monomer (b1) is other than BA, the copolymerization ratio [1 / γ _{(b3 / b1)} ] of the desired monomer with the monomer (b1) is determined by the same method as described above. Since it can obtain | require by calculation, copolymerization ratio [1 / ₍ gamma _{) (b3 / b1)} ] is 0.5 among these monomers.
The above monomers may be appropriately selected and used as the monomer (b3).

  The amount of the monomer (b3) used can be appropriately selected depending on the type of the monomer (b3) and the types of the monomer (b1) and the monomer (b2). , Based on a total of 100% by weight of the monomers (b1) to (b3) constituting the acrylic polymer (B), 5 to 85% by weight, preferably 5 to 70% by weight, more preferably 10 to 60%. % By weight, particularly preferably 15 to 50% by weight. It is preferable that the amount of the monomer (b3) used is equal to or greater than the lower limit value because the cohesive force of the pressure-sensitive adhesive composition is sufficient, foaming hardly occurs in the durability test, and reworkability is good. Moreover, if the usage-amount of a monomer (b3) is below an upper limit, since the adhesive composition can exhibit sufficient adhesiveness with respect to a support substrate, and durability which does not produce peeling etc. can be exhibited, it is preferable. .

  The acrylic polymer (B) may be a monomer having a reactive functional group capable of reacting with a functional group of the crosslinking agent (C) to form a crosslinked structure, for example, the monomer (b2), if necessary. ) Can include the carboxyl group-containing monomer and the hydroxyl group-containing monomer exemplified as), and the amide group-containing monomer exemplified as the monomer (b3).

  The weight average molecular weight (Mw) of the acrylic polymer (B) is to provide sufficient cohesive force to the pressure-sensitive adhesive composition, to suppress the generation of bubbles in the durability test, and to provide reworkability. 50,000 or more, preferably 60,000 or more, particularly preferably 70,000 or more. The acrylic polymer (B) has a weight average molecular weight (Mw) of 300,000 or less, preferably 220,000 or less, for the purpose of imparting flexibility to the pressure-sensitive adhesive composition and suppressing the occurrence of white spots. Particularly preferably, it is set to 160,000 or less.

The glass transition point (Tg _B ) of the acrylic polymer (B) is −40 ° C. for the purpose of giving sufficient cohesive force to the pressure-sensitive adhesive composition.
As mentioned above, Preferably it shall be -30 degreeC or more. In addition, the glass transition point (Tg _B ) of the acrylic polymer (B) is intended to exhibit sufficient wettability to the support substrate in the pressure-sensitive adhesive composition, and to exhibit durability that does not cause peeling. 5 ° C. or lower, preferably −5 ° C. or lower.

The solubility parameter (SP _B ) of the acrylic polymer ( _B ) is 17.7 J for the purpose of maintaining compatibility with the acrylic polymer (A) and giving sufficient cohesive force to the pressure-sensitive adhesive composition. ^1/2 / cm ^3/2 or more, preferably 18.2 J ^1/2 / cm ^3/2 or more. In addition, the solubility parameter (SP _B ) of the acrylic polymer (B) according to the present embodiment maintains compatibility with the acrylic polymer (A) and has sufficient wettability with respect to the support substrate. For the purpose of exerting durability to the object and exhibiting no peeling or the like, 19.0 J ^1/2 / cm ^3/2 or less, preferably 18.8 J ^1/2 / cm ^3/2 or less.

The difference (ΔSP = SP _B −SP _A ) between the solubility parameter (SP _B ) of the acrylic polymer ( _B ) and the solubility parameter (SP _A ) of the acrylic polymer ( _A ) is −0.5 to 0.5 is preferable, -0.4 to 0.4 is more preferable, and -0.2 to 0.2 is particularly preferable. A difference in solubility parameter (ΔSP) within the above range is preferable because the compatibility between the acrylic polymer (A) and the acrylic polymer (B) is extremely excellent.

The polymerization method of the acrylic polymer (B) according to the present embodiment is not particularly limited, and the polymerization can be performed by the same method as described in the polymerization method of the acrylic polymer.
In addition, when manufacturing an acrylic polymer (B), it is preferable to use the organic solvent which produces a chain transfer easily, for example, alcohols and aromatic hydrocarbons. In particular, toluene, isopropyl alcohol, and the like are preferable in view of the ease of the polymerization reaction.

Moreover, when manufacturing an acrylic polymer (B), a chain transfer agent can also be used. Examples of the chain transfer agent include cyanoacetic acid; alkyl esters having 1 to 8 carbon atoms of cyanoacetic acid; bromoacetic acid; alkyl esters having 1 to 8 carbon atoms of bromoacetic acid; anthracene, phenanthrene, fluorene, 9-phenylfluorene. Aromatic compounds such as p-nitroaniline, nitrobenzene, dinitrobenzene, p-nitrobenzoic acid, p-nitrophenol and p-nitrotoluene; benzoquinone, 2,3,5,6-tetra Benzoquinone derivatives such as methyl-p-benzoquinone; borane derivatives such as tributylborane; carbon tetrabromide, carbon tetrachloride, 1,1,2,2-tetrabromoethane, tribromoethylene, trichloroethylene, bromotrichloromethane, tri Bromomethane, 3-chloro-1-propene, etc. Halogenated hydrocarbons;
Aldehydes such as chloral and furaldehyde: alkyl mercaptans having 1 to 18 carbon atoms; aromatic mercaptans such as thiophenol and toluene mercaptan; mercaptoacetic acid; alkyl esters having 1 to 10 carbon atoms of mercaptoacetic acid; 12 hydroxyalkyl mercaptans; terpenes such as binene and terpinolene can be used.

  When the acrylic polymer (B) is produced, among the chain transfer agents, preferably mercaptans and halogenated hydrocarbons are added in an amount of 0.005 to 3 parts by weight based on 100 parts by weight of the total amount of monomers. Can be used.

The ratio of mixing the acrylic polymer (A) and the acrylic polymer (B) is a weight for the purpose of giving sufficient cohesive force to the pressure-sensitive adhesive composition and suppressing the occurrence of foaming in the durability test. The ratio (weight of acrylic polymer (A) / weight of acrylic polymer (B)) is 50/50 or more, preferably 60/40 or more, and particularly preferably 70/30 or more. Moreover, the ratio which mixes an acrylic polymer (A) and an acrylic polymer (B) gives a softness | flexibility to an adhesive composition, and suppresses generation | occurrence | production of peeling and generation | occurrence | production of a white spot in a durability test. For this purpose, the weight ratio (weight of acrylic polymer (A) / weight of acrylic polymer (B)) is 95/5 or less, preferably 90/10 or less.

  The pressure-sensitive adhesive composition according to the present embodiment is 0.01 to 5 parts by weight of the crosslinking agent (C) with respect to 100 parts by weight of the mixture of the acrylic polymer (A) and the acrylic polymer (B). And a crosslinking agent (C) containing two or more functional groups capable of reacting with the acrylic copolymer (A) to form a crosslinked structure.

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

  Examples of the isocyanate compound include aromatic isocyanates such as xylylene diisocyanate, diphenylmethane diisocyanate, triphenylmethane triisocyanate, and tolylene diisocyanate; An isocyanate compound derived from various 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.

  Examples of the isocyanate compound include “Coronate L”, “Coronate HX”, “Coronate HL-S”, “Coronate 2234” (manufactured by Nippon Polyurethane Industry Co., Ltd.), “Desmodur N3400” (manufactured by Sumitomo Bayer Urethane Co., Ltd.). ] "Duranate E-405-80T", "Duranate TSE-100" (manufactured by Asahi Kasei Chemicals Corporation), "Takenate D-110N", "Takenate D-120N", "Takenate M-631N" A product commercially available under a trade name such as “Chemical Co., Ltd.” can be preferably used.

  Among these, as the isocyanate compound, an isocyanate compound derived from hexamethylene diisocyanate or xylene diisocyanate is preferable, and an isocyanate compound derived from hexamethylene diisocyanate is particularly preferable.

  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, hydroquinone diglycidyl ether, 2 , 2-Dibromoneope Tilglycol 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.

  Among the epoxy compounds, an epoxy compound containing two epoxy groups is preferable, and among them, use of an epoxy compound such as polyethylene glycol diglycidyl ether, resorcin diglycidyl ether, hydroquinone diglycidyl ether is more preferable. Examples of such epoxy compounds include “SR-8EG” (manufactured by Sakamoto Yakuhin Kogyo Co., Ltd.), “Denacol EX-201”, “Denacol EX-203” (manufactured by Nagase Chemmutex Co., Ltd.), and the like. Those commercially available can be suitably used.

  The amount of the crosslinking agent (C) used relative to 100 parts by weight of the mixture of the acrylic polymer (A) and the acrylic polymer (B) gives sufficient cohesive force to the pressure-sensitive adhesive composition and suppresses the generation of bubbles. For this purpose, the content is 0.01 parts by weight or more, preferably 0.3 parts by weight or more. The amount of the crosslinking agent (C) used relative to 100 parts by weight of the acrylic copolymer (A) is 5 parts by weight or less, preferably 3 for the purpose of suppressing peeling due to excessive cohesive strength of the pressure-sensitive adhesive composition. Part by weight or less, particularly preferably 2 parts by weight or less.

  In particular, when the isocyanate compound is used as the crosslinking agent (C), the amount used is 0.15 parts by weight or more and 3 parts by weight with respect to 100 parts by weight of the mixture of the acrylic polymer (A) and the acrylic polymer (B). Parts by weight or less, preferably 0.3 parts by weight or more and 2 parts by weight or less, particularly preferably 0.4 parts by weight or more and 1 part by weight or less. The amount used when using the aziridine compound is 0.001 part by weight or more and 0.1 part by weight or less with respect to 100 parts by weight of the mixture of the acrylic polymer (A) and the acrylic polymer (B). Preferably it is 0.001 part by weight or more and 0.05 part by weight or less. Furthermore, when using an epoxy compound, the usage-amount is 0.005 weight part or more and 0.3 weight part or less with respect to 100 weight part of mixtures of an acrylic polymer (A) and an acrylic polymer (B), Preferably 0.01 parts by weight or more and 0.2 parts by weight or less

  Moreover, a crosslinking agent (C) can be used combining 2 or more types as above-mentioned, and it is good to combine an isocyanate compound and an aziridine compound or an isocyanate compound and an epoxy compound. In that case, the isocyanate compound, the aziridine compound, and the epoxy compound can be appropriately selected within the above-mentioned usage amount ranges, but preferably, the isocyanate compound: aziridine compound = 1 to 500: 1, particularly by weight ratio. It is good to use it so that it may become the range of 10-300: 1 or an isocyanate compound: epoxy compound = 1-300: 1, especially 1-50: 1.

  The pressure-sensitive adhesive composition according to the present embodiment contains a terpene phenol resin (D).

  The terpene phenol resin (D) is produced by cationic polymerization of a terpene compound and phenol under a Friedel-Craft catalyst, and is obtained by hydrogenating a terpene phenol resin. It may be.

Terpenes are generally polymers of isoprene (C5H8) and are classified into monoterpenes (C10H16), sesquiterpenes (C15H24), diterpenes (C20H32), and the like. A terpene compound is a compound having these as a basic skeleton. Specific examples of these terpene compounds include the following, but the present invention is not limited thereto.

  As the terpene compound, myrcene, alloocimene, ocimene, α-pinene, β-pinene, dipentene, limonene, α-ferrandrene, α-terpinene, γ-terpinene, terpinolene, 1,8-cineole, 1,4-cineole, Examples include α-terpineol, β-terpineol, γ-terpineol, camphene, tricyclene, sabinene, paramentadienes, and carenes.

Examples of phenols include, but are not limited to, phenol, cresol, xylenol, catechol, resorcin, hydroquinone, bisphenol A, and the like.

  Examples of the terpene phenol resin (D) include “YS Polystar U Series”, “YS Polystar T Series”, “YS Polystar S Series”, “Mighty Ace G Series”, “Mighty Ace K Series” [Yasuhara Chemical Co., Ltd.] Etc.] is exemplified. These terpene phenol resins may be used alone or as a mixture of two or more.

  The amount of the terpene phenol resin (D) used for 100 parts by weight of the mixture of the acrylic copolymer (A) and the acrylic polymer (B) suppresses peeling and foaming in the heat shock test, and further generates white spots. In order to suppress the above, the amount is 1 part by weight or more, preferably 3 parts by weight or more, particularly preferably 5 parts by weight or more. Moreover, the usage-amount of the terpene phenol resin (D) with respect to 100 weight part of the mixture of an acrylic copolymer (A) and an acrylic polymer (B) suppresses foaming of an adhesive layer in a durability test. For the purpose, it is 40 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 of the present invention can further use a silane coupling agent (E). Examples of such silane coupling agents (E) include 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. An organic substituent-containing silicone alkoxy oligomer; a mercapto group-containing silane coupling agent such as γ-mercaptopropyltrimethoxysilane, γ-mercaptopropyltriethoxysilane, γ-mercaptopropyldimethoxymethylsilane; Contains alicyclic epoxy groups such as 4-epoxycyclohexyl) ethyltrimethoxysilane and β- (3,4-epoxycyclohexyl) ethyltriethoxysilane Silane coupling agents; for example, epoxy group-containing silane couplings such as methyltri (glycidyl) silane, γ-glycidoxypropylmethyldimethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropyltriethoxysilane Agents; 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-amino Propyltrimethoxysilane, N- (β-aminoethyl) -γ-aminopropyltriethoxysilane, γ-aminopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, N-phenyl-γ-aminopropyltrimethoxysilane, etc. An amino group-containing silane coupling agent; a hydroxyl group-containing silane coupling agent such as γ-hydroxypropyltrimethoxysilane; an amide group-containing silane compound such as γ-amidopropyltrimethoxysilane; Isocyanurate-containing silane coupling agents such as isocyanatepropyltrimethoxysilane; for example, isocyanurates such as tris (3-trimethoxysilylpropyl) isocyanurate and tris (3-triethoxysilylpropyl) isocyanurate Such as preparative skeleton-containing silane coupling agent can be used. Use of the silane coupling agent (E) is preferable for improving durability, and for the purpose of achieving both durability and reworkability, it is preferable to use a mercapto group-containing silane coupling agent.

  The use amount of the silane coupling agent (E) with respect to 100 parts by weight of the mixture of the acrylic polymer (A) and the acrylic polymer (B) is 0 for the purpose of improving the durability of the pressure-sensitive adhesive composition. 0.03 to 3 parts by weight, preferably 0.05 to 1.5 parts by weight.

  Moreover, a silicone compound (F) can be used for the adhesive composition which concerns on this Embodiment. By adding the silicone compound (F) to the pressure-sensitive adhesive composition, the adhesive force can be reduced, and the rework work can be easily performed.

  Examples of the silicone compound (F) include polyether-modified polydimethylsiloxane, aralkyl-modified polydimethylsiloxane, amino-modified polydimethylsiloxane in which methyl groups at both ends, one end, or side chain of polydimethylsiloxane are substituted with other functional groups. , Epoxy-modified polydimethylsiloxane, carboxyl group-modified polydimethylsiloxane, carbinol-modified polydimethylsiloxane, mercapto group-modified polydimethylsiloxane, and other modified polydimethylsiloxanes can be used. From the viewpoint of durability and reworkability, polyether Modified polydimethylsiloxane and amino-modified polydimethylsiloxane are preferred. Moreover, a silicone compound may be individual and may use 2 or more types together.

  Examples of the polyether-modified polydimethylsiloxane include “KF-351A, KF-352A, KF-353, KF-354L, KF-355A, KF-615A, KF-945, KF-640, KF-641, KF-642. , KF-643, KF-6020, X-22-6191, X-22-4515, KF-6011, KF-6012, KF-6013, KF-6015, KF-6016, KF-6017, X-22-4741 , KF-1002, X-22-4952, X-22-4272, X-22-6266, KF-6004, KP-301, KP-323, KP-354, KP-355, KP-341, KP-118 , F-501, X-22-3506, X-22-3004, KF-6005, KP-101, KF-889, K -6003, X-22-4515, F-3031, X-24-1430, X-22-4991, KP-208 (manufactured by Shin-Etsu Chemical Co., Ltd.) and the like are used. be able to.

  Examples of the amino-modified polydimethylsiloxane include “KF-8010, X22-161A, X22-161B, X22-1660B-3, KF-8008, KF-8012, KF-393, KF-859, KF-860, KF- 861, KF-865, KF-867, KF-867S, KF-869, KF-880, KF-8015, KF-8002, KF-8004, KF-8005, KF-858, KF-864, KF-865, Commercially available products such as “KF-868, KF-8003” (manufactured by Shin-Etsu Chemical Co., Ltd.) can be used.

The use amount of the silicone compound (F) with respect to 100 parts by weight of the mixture of the acrylic polymer (A) and the acrylic polymer (B) is intended to suppress the adhesive strength of the adhesive and the increase in adhesive strength over time. As 0.05 parts by weight or more, preferably 0.1 parts by weight or more. Moreover, the usage-amount of the silicone compound (F) with respect to 100 weight part of the mixture of an acrylic polymer (A) and an acrylic polymer (B) keeps an adhesive and a to-be-adhered body favorable adhesiveness, For the purpose of suppressing the occurrence of peeling in the durability test, it is 1 part by weight or less, preferably 0.5 part by weight or less, particularly preferably 0.3 part by weight or less.

  The pressure-sensitive adhesive composition according to the present embodiment includes the above-described acrylic polymer (A), acrylic polymer (B), crosslinking agent (C), terpene phenol resin (D), and silane coupling agent (E). In addition to the silicone compound (F), various additives (solvents, weather resistance stabilizers, plasticizers, softeners, etc.) in amounts that do not impair the effects exhibited by the pressure-sensitive adhesive composition according to the present embodiment. Dyes, pigments, inorganic fillers, and the like) can be appropriately blended.

  The range of the blending amount of the weather resistance stabilizer, plasticizer, softener, dye, pigment, inorganic filler, etc. is 100 parts by weight of the mixture of the acrylic polymer (A) and the acrylic polymer (B). It is preferably 30 parts by weight or less, more preferably 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 present embodiment, a crosslinked structure is formed between the acrylic polymer (A) and, if necessary, the acrylic polymer (B) and the crosslinking agent (C). After that, the gel content is 30 to 80% by weight, preferably 35 to 55% by weight. If the gel content is equal to or higher than the lower limit value, it is preferable because inconveniences such as generation of bubbles can be suppressed, and if the gel content is equal to or lower than the upper limit value, problems such as peeling and white spots are hardly generated. The gel content is measured by the following method.

The gel content can be measured by the following method.
<Measurement of gel content of pressure-sensitive 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 hot air circulation type at 100 ° C. for 90 seconds. Dry with a drier 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 50% 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) Immerse the wire mesh 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 (6).
Gel content (% by weight) = (C−A) / (B−A) × 100 (6)
In the above formula, A is the weight of the wire mesh (g), B is the weight of the wire mesh (adhesive weight) (g), and C is the weight of the wire mesh (gel resin weight) dried after immersion. (G).

(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 this Embodiment is an optical film which has the adhesive layer formed from the adhesive composition which concerns on embodiment. The specific manufacturing method forms an adhesive layer on a peeling sheet by apply | coating the adhesive composition which concerns on embodiment on a peeling sheet, and drying. 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 present embodiment is provided with a release sheet 4, an adhesive layer 3 provided on the release sheet 4 and made of the adhesive composition according to the present embodiment, and an adhesive. An optical film material 2 provided on the layer 3 and a protective film 1 provided on the optical film material 2 are provided. Moreover, as shown in FIG. 2, the optical film which concerns on the modification of this Embodiment is provided on the peeling sheet 4 and the peeling sheet 4, and the adhesion layer 3 which consists of an adhesive composition which concerns on this Embodiment. On the optical film material 2 provided on the adhesive layer 3, the adhesive layer 5 further provided on the optical film material 2, the optical film material 6 provided on the adhesive layer 5, and the optical film material 6 The protective film 1 provided is provided.

  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 onto the release sheet can be dried with a hot air dryer under heating conditions of 70 ° C. or higher and 120 ° C. or lower and 1 minute or longer and 3 minutes or shorter.

The adhesive strength of the optical film provided with the pressure-sensitive adhesive composition according to the present embodiment and the pressure-sensitive adhesive layer made of this pressure-sensitive adhesive composition is that of the acrylic polymer (A) and the acrylic polymer (B). By adjusting the type and amount of the reactive functional group, the crosslinking agent (C), the terpene phenol resin (D), the silane coupling agent (E), the silicone compound (F), etc., the desired adhesive strength can be adjusted. The adhesive strength of the optical film including the pressure-sensitive adhesive composition and the pressure-sensitive adhesive layer made of the pressure-sensitive adhesive composition to the adherend is, for example, 0.5 N / 25 mm or more. By having an adhesive strength in the above range, occurrence of peeling can be suppressed in the durability test. The upper limit of the adhesive force is not particularly limited, but is preferably 15 N / 25 mm or less, particularly preferably 10 N / 25 mm or less in consideration of performing rework work. By having an adhesive force in the above range, after the optical film is bonded to the adherend, the rework operation can be easily performed when the rework operation becomes necessary.

(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 present embodiment is a liquid crystal display device including the optical film according to the present embodiment. Moreover, a liquid crystal display device can be manufactured by sticking the optical film according to the present embodiment to one side or both sides of a liquid crystal cell via an adhesive layer of the optical film. For example, as shown in FIG. 3, in the liquid crystal display device, an optical film material 2 composed of a polarizing film 21 and a reflective layer 22 is attached to one surface of a liquid crystal cell 5 via an adhesive layer 3 according to the present embodiment. The polarizing film 21 is bonded to the other surface of the liquid crystal cell 5 via the adhesive layer 3 and manufactured. 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.

(Effect of embodiment)
Since the optical film comprising the pressure-sensitive adhesive composition according to the embodiment and the pressure-sensitive adhesive layer comprising this pressure-sensitive adhesive composition has the above-described configuration, it has a high weight average molecular weight and a molecular weight distribution having a broad distribution on the low molecular weight side. And the acrylic polymer (B) having a low weight average molecular weight and a relatively high glass transition point provide a good balance between cohesive force and stress relaxation properties. , Both durability and suppression of white spots can be achieved, and addition of terpene phenol resin (D) further suppresses the occurrence of white spots without deteriorating the durability, thereby improving heat shock resistance. Can be improved. Therefore, the pressure-sensitive adhesive composition according to the embodiment can achieve durability and suppression of occurrence of white spots at a high level, and is excellent in durability and suppression of white spots under a high temperature environment of 100 ° C. or higher. Excellent heat shock resistance under severe conditions.

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

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

<Creation of optical film for test>
A polarizing film having a pressure-sensitive adhesive layer was produced 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 50% RH for 10 days to obtain a polarizing film having an adhesive layer.

<Measurement of adhesive strength>
After the polarizing film prepared in “Creation of optical film for test” was cut to 25 mm × 150 mm, this polarizing film piece was 0.7 mm thick using a table laminating machine, alkali-free glass plate “# 1737” manufactured by Corning. A test sample was prepared by pressure bonding. This sample was autoclaved (50 ° C., 5 kg / cm ² , 20 minutes). Next, this sample was allowed to stand for 1 hour under the conditions of 23 ° C. and 50% RH, and then the adhesive strength at 180 ° peeling (peeling speed: 300 mm / min) was measured.

<Evaluation of heat resistance and heat resistance>
Using a 15-inch (196 mm × 325 mm (long side)) test piece obtained by cutting the polarizing film prepared in “Preparation of optical film for test” so that the long side is 45 ° with respect to the absorption axis, a 0. A 7 mm Corning non-alkali glass plate “# 1737” was attached to one side using a laminator. Next, this sample was subjected to autoclaving (50 ° C., 5 kg / cm ² , 20 minutes), and allowed to stand at 23 ° C. and 50% RH for 24 hours to obtain a test sample. Test samples were prepared for each of the heat resistance evaluation and the heat and humidity resistance evaluation. Thereafter, the test sample for heat resistance evaluation was allowed to stand for 500 hours under a temperature condition of 105 ° C., and the heat resistance was evaluated by visually observing the state of foaming, peeling and floating. Moreover, the test sample for heat and moisture resistance evaluation was allowed to stand for 500 hours under the condition of 40 ° C. and 95% RH, and the heat and humidity resistance was evaluated by visually observing the state of peeling or floating. The evaluation criteria are as follows.

(Heat resistance evaluation criteria)
a) Foaming ◯: Foaming is not observed at all or foaming is slightly observed, but at a level that does not cause any practical problems.
X: Foaming is clearly seen.

b) Peeling ◎: Peeling is 0.3 mm or less.
○: Peeling greater than 0.3 mm and 0.5 mm or less.
Δ: Peeling greater than 0.5 mm and 0.8 mm or less.
X: Peeling is larger than 0.8 mm.

(Evaluation criteria for heat and humidity resistance)
a) Peeling ◎: Peeling is 0.3 mm or less.
○: Peeling greater than 0.3 mm and 0.5 mm or less.
Δ: Peeling greater than 0.5 mm and 0.8 mm or less.
X: Peeling is larger than 0.8 mm.

<Evaluation of heat shock resistance>
Using a 15-inch (196 mm × 325 mm (long side)) test piece obtained by cutting the polarizing film prepared in “Preparation of optical film for test” so that the long side is 45 ° with respect to the absorption axis, a 0. A 7 mm Corning non-alkali glass plate “# 1737” was attached to one side using a laminator. Next, this sample was subjected to autoclaving (50 ° C., 5 kg / cm ² , 20 minutes), and allowed to stand at 23 ° C. and 50% RH for 24 hours to obtain a test sample. Then, the heat shock test which makes a test sample 1 cycle at -45 degreeC 30 minutes and 80 degreeC 30 minutes was performed 100 cycles, and it evaluated by visually observing the state of peeling about heat shock resistance. The evaluation criteria are as follows.

(Evaluation criteria for heat shock resistance)
a) Peeling ◎: Peeling is 0.3 mm or less.
○: Peeling greater than 0.3 mm and 0.5 mm or less.
Δ: Peeling greater than 0.5 mm and 0.8 mm or less.
X: Peeling is larger than 0.8 mm.

<Evaluation test for white spots>
Using a test piece of 15 inch size, that is, 196 mm × 325 mm (long side) obtained by cutting the polarizing film prepared in “Creation of optical film for test” so that the long side is 45 ° with respect to the absorption axis, A test sample in which a polarizing film having an adhesive layer was stuck on both surfaces of a 0.7 mm Corning non-alkali glass plate “# 1737” so that the polarization axes thereof were orthogonal to each other was prepared. Next, this sample was subjected to autoclaving (50 ° C., 5 kg / cm ² , 20 minutes), and left for 24 hours at 23 ° C. and 50% RH. Then, it was left to stand at 105 ° C. under dry conditions for 500 hours. After standing, use a uniform light source (manufactured by I-System Co., Ltd.) under conditions of 23 ° C. and 50% RH, and brightness of 17 × 31 points (527 points) with EyeScale-3W (manufactured by I-System Co., Ltd.) Were measured, and the whiteout state was evaluated by their maximum luminance value (cd / m ² ) and visual observation. The evaluation criteria are as follows.

(Outline evaluation criteria)
(Double-circle): A white spot is hardly recognized and a maximum brightness | luminance is 10 cd / m < ² > or less.
◯: Almost no white spots are observed, and the maximum luminance is greater than 10 cd / m ² and 15 cd / m ² or less.
△: White spots were observed slightly, the maximum brightness is greater than 15 cd / ^{m 2,} is 20 cd / ^{m 2} or less.
X: White spots are clearly recognized, and the maximum luminance is larger than ²⁰ cd / m ² .

<Production of acrylic polymer (A)>
(Production Example 1)
In a reactor equipped with a thermometer, a stirrer, a nitrogen inlet tube and a reflux condenser, 99 parts by weight of n-butyl acrylate (BA), 1 part by weight of acrylic acid (AA), and 75 parts by weight of ethyl acetate (EAc) are placed. The air in the reaction vessel was replaced with nitrogen gas. Thereafter, the temperature of the content of the reaction vessel was raised to 70 ° C. with stirring in a nitrogen atmosphere, and 0.02 part by weight of 2,2′-azobis (2,4-dimethylvaleronitrile) was added to 25 parts by weight of ethyl acetate. The solution in which was dissolved was added dropwise over 4 hours, and then reacted for 0.5 hours. Further, a solution in which 0.1 part by weight of t-butyl peroxypivalate was dissolved in 100 parts by weight of toluene was dropped over 1 hour, and then reacted for 1.5 hours. After completion of the reaction, the reaction solution was diluted with ethyl acetate to obtain an acrylic polymer solution having a solid content of 21 wt%. The weight average molecular weight (Mw) of the acrylic polymer (A) according to Production Example 1 was 16.3 million, Mw / Mn was 16.6, and (Mw / Mn) / (Mz / Mw) was 4.5.

(Production Example 2)
An acrylic copolymer solution was obtained in the same manner as in Production Example 1 except that the polymer composition was changed to the monomer composition shown in Table 1.

<Production of acrylic polymer (B)>
(Production Example 3)
In a reactor equipped with a thermometer, a stirrer, a nitrogen introduction tube and a reflux condenser, n-butyl acrylate (BA) 36 parts by weight, methyl acrylate (MA; copolymerization ratio to BA (1 / γ _{MA / BA} ) = 0.738) 20% by weight of a monomer mixture comprising 20 parts by weight, n-butyl methacrylate (nBMA; copolymerization ratio to BA (1 / _{γnBMA / BA} ) = 0.395) 44 parts by weight 10 parts by weight of ethyl acetate, 30 parts by weight of toluene and 0.04 part by weight of azobisisobutyronitrile were added and heated, and the reaction was allowed to proceed at reflux temperature for 20 minutes. Next, a solution comprising 80% by weight of the remaining monomer mixture, 20 parts by weight of ethyl acetate, and 0.25 parts by weight of azobisisobutyronitrile was added dropwise over 120 minutes under reflux temperature conditions, and then reacted for 30 minutes. I let you. Further, a solution consisting of 10 parts by weight of ethyl acetate and 0.25 parts by weight of azobisisobutyronitrile was added dropwise over 30 minutes, and then reacted for 90 minutes. After completion of the reaction, the reaction mixture was diluted with toluene to obtain an acrylic polymer solution having a solid content of 47% by weight. The weight average molecular weight (Mw) of the acrylic polymer (B) according to Production Example 3 was 100,000.

Composition of monomers used in Production Examples 1 and 2 above, solid content of the obtained acrylic copolymer (A) solution, glass transition point (Tg), solubility parameter (SP value), weight average molecular weight (Mw) ), Mw / Mn, Mz / Mw, (Mw / Mn) / (Mz / Mw) are shown in Table 1. Further, the composition of the monomer used in Production Example 3 above, the solid content of the obtained acrylic copolymer (B) solution, glass transition point (Tg), solubility parameter (SP value), weight average molecular weight (Mw) ) Is shown in Table 2.

In addition, the symbol of each monomer in Table 1-Table 2 is as follows.
BA: n-butyl acrylate MA: methyl acrylate AA: acrylic acid M5300: ω-carboxypolycaprolactone monoacrylate (n≈2), molecular weight about 300, product name Aronics M-5300, manufactured by Toagosei Co., Ltd. n-BMA: n-Butyl methacrylate

<Manufacture of pressure-sensitive adhesive composition for optical film>
Example 1
As shown in Table 3, 333 weight of the acrylic polymer (A) solution produced in Production Example 1 so that the blend ratio of the acrylic polymer (A) and the acrylic polymer (B) is 70:30. Part (however, 70 parts by weight as an active ingredient) and 64 parts by weight (however, 30 parts by weight as an active ingredient) of the acrylic polymer (B) solution produced in Production Example 3 were mixed, and terpene phenol was added to this mixture. Resin (D) 10 parts by weight of TH-130 (hydrogenated terpene phenol resin manufactured by Yasuhara Chemical Co., Ltd., 10 parts by weight of active ingredient), E405 0.63 parts by weight (product of Asahi Kasei Chemicals Co., Ltd., product) Name Duranate E-405-80T, active ingredient 0.5 part by weight) and EX201 0.07 part by weight (manufactured by Nagase ChemteX Corporation, trade name Denacol EX-201, available 0.07 parts by weight of component) and 1.23 parts by weight of S810 (manufactured by Chisso Co., Ltd., trade name Silaace S810, active ingredient 1.23 parts by weight) as the silane coupling agent (E) The pressure-sensitive adhesive composition according to Example 1 was obtained by stirring and mixing.

(Other examples, comparative examples, and reference examples)
A pressure-sensitive adhesive composition (that is, Examples 2-3 and Comparative Examples) in the same manner as in Example 1 except that the composition of each example shown in Tables 3 to 4 was employed instead of the composition in Example 1. 1 to 3 were produced. 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 results for each example are shown in Tables 3-4.

In addition, the symbol of each compound in Table 3-Table 4 is as follows, and the addition amount of each component is a weight part of an active ingredient.
TH-130: “YS Polystar TH-130”, hydrogenated terpene phenol resin, active ingredient 100%, Yashara Chemical Co., Ltd. E405: “Duranate E-405-80T”, modified hexamethylene diisocyanate, 80% active ingredient %, NCO content 7.1% by weight, manufactured by Asahi Kasei Chemicals Corporation EX201: “Denacol EX-201”, resorcin diglycidyl ether, active ingredient 100% by weight, Nagase ChemteX Corporation KP-355: “KP -355 ", polyether-modified polydimethylsiloxane, 100% active ingredient, manufactured by Shin-Etsu Chemical Co., Ltd. S810:" Silaace S810 "gamma-mercaptopropyltrimethoxysilane, 100% by weight active ingredient, manufactured by Chisso Corporation X- 41-1810: “X-41-1810”, Merca Pto group-containing silicone alkoxy oligomer, 100% by weight active ingredient, manufactured by Shin-Etsu Chemical Co., Ltd.

  In addition, the optical film having the pressure-sensitive adhesive for optical films according to the embodiment and the examples has good durability under high temperature environment and high humidity environment, excellent heat shock resistance, and white spots are suppressed. Therefore, the present invention can be applied to optical films used in display devices such as personal 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 the combinations of features described in the embodiments and examples are necessary for the means for solving the problems of the invention.

The cross section of the optical film which concerns on this Embodiment is shown. The cross section of the optical film which concerns on the modification of this Embodiment is shown. The outline of the section of the liquid crystal display concerning this embodiment is shown. The outline of the section of the liquid crystal display concerning a modification of this embodiment is shown.

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 (7)

Containing a reactive functional group, having a weight average molecular weight (Mw) of 1,000,000 to 2,500,000, a ratio of a weight average molecular weight to a number average molecular weight (Mn) (Mw / Mn) of 9 to 30; The value ((Mw / Mn) / (Mz / Mw)) obtained by dividing Mn) by the ratio (Mz / Mw) of the Z average molecular weight (Mz) to the weight average molecular weight is 2 or more, and the glass transition point is −45 ° C. or less. An acrylic polymer (A),
An acrylic polymer (B) having a weight average molecular weight (Mw) of 50,000 to 300,000 and a glass transition point of −40 ° C. or more and 5 ° C. or less;
For 100 parts by weight of the mixture of the acrylic polymer (A) and the acrylic polymer (B),
0.01 parts by weight or more and 5 parts by weight or less, a crosslinking agent (C) to be added;
A pressure-sensitive adhesive composition comprising 1 part by weight or more and 40 parts by weight or less, and a terpene phenol resin (D) added. The pressure-sensitive adhesive composition according to claim 1, wherein the acrylic polymer (A) and the acrylic polymer (B) are contained in a weight ratio of 50/50 to 95/5. Furthermore, the adhesive composition of any one of Claims 1-2 containing a silane coupling agent (E).   The pressure-sensitive adhesive composition according to any one of claims 1 to 3, further comprising a silicone compound (F). The gel content of the pressure-sensitive adhesive layer formed from the pressure-sensitive adhesive composition after the crosslinked structure is formed is 30% by weight or more and 80% by weight or less. Adhesive composition. The optical film which has an adhesive layer formed from the adhesive composition of any one of Claims 1-5. A liquid crystal display device comprising the optical film according to claim 6.