JP2010159346A - Pressure-sensitive adhesive agent and optical film - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a pressure-sensitive adhesive agent for an optical film that is used for pasting an optical film, exhibits excellent durability even in a high-temperature or high-temperature high-humidity environment, suppresses occurrence of light leakage from the periphery and can be easily reworked when re-pasting of the optical film is required, and an optical film. <P>SOLUTION: The pressure-sensitive adhesive agent composition comprises an acrylic copolymer (A) bearing a reactive functional group, and 5-30 pts.wt. of an isocyanate compound (B), 0.05-1 pt.wt. of a polyether-modified silicone (C) and 0.03-1 pt.wt. of a silane coupling agent (D), each based on 100 pts.wt. of the acrylic copolymer. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a pressure-sensitive adhesive composition, a pressure-sensitive adhesive, and an optical film having the pressure-sensitive adhesive layer used for attaching an optical film such as a polarizing film or a retardation film to an adherend such as a liquid crystal cell. More specifically, the present invention can be peeled off when a problem occurs when an optical film is attached to an adherend, exhibits excellent durability even at high temperature or high temperature and high humidity, and is less likely to cause white spots. The present invention relates to a pressure-sensitive adhesive composition having the above characteristics, a pressure-sensitive adhesive, and an optical film having the pressure-sensitive adhesive layer.

  A liquid crystal display device used in a wide range of fields as a 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, a polarizing film, and a phase difference It is comprised from optical films, such as a film and a brightness enhancement film, and the adhesive is often used for lamination | stacking of optical films and sticking 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 a pressure-sensitive adhesive that is excellent in durability even in a severe environment such as high temperature or high temperature and high humidity, that is, that does not peel off even when used for a long period of time and does not generate bubbles. Yes.

In a severe environment such as high temperature or high temperature and high humidity, the optical film has a large dimensional change such as shrinkage and expansion. In the state where such an optical film is attached to an adherend such as a liquid crystal cell, when exposed to a high temperature or high temperature and high humidity environment, the pressure-sensitive adhesive that does not peel off or generate bubbles is agglomerated. A pressure-sensitive adhesive that has high strength and adheres strongly to the adherend is used. Further, under high temperature or high temperature and high humidity, the distribution of residual stress acting on the optical film becomes non-uniform, and stress concentration occurs on the outer periphery of the optical film attached to the liquid crystal cell. There is a problem that a phenomenon called so-called “white void” is likely to occur due to leakage of white.

  In addition, in this technical field, when an optical film having an adhesive layer is stuck to an adherend, the optical film is peeled from the adherend in the event of problems such as biting of foreign matter and misalignment.・ Rework work is performed to remove and reapply a new optical film. At this time, when the adhesive strength of the optical film is large, it is difficult to peel the optical film from the adherend, or a part of the adhesive remains on the adherend after the optical film is peeled off. Had occurred.

  As described above, the pressure-sensitive adhesive used for the optical film is required to have durability that must be adhered to an adherend such as a liquid crystal cell so that bubbles do not occur even when used under high temperature or high temperature and high humidity. Is done. On the other hand, at the time of reworking work, a characteristic (hereinafter referred to as “reworkability”) is required in which a part of the pressure-sensitive adhesive is not easily left on the adherend. Thus, there is a demand for a pressure-sensitive adhesive that achieves both conflicting durability and reworkability, and suppression of white spots.

  Various studies have been made to solve the above problems. For example, in Japanese Patent Application Laid-Open No. 2004-331697 (Patent Document 1), a pressure-sensitive adhesive having both durability, reworkability and suppression of white spots has a weight average molecular weight of 1 million to 2 million having a reactive functional group. 100 parts by weight of a copolymer, 20 to 100 parts by weight of a copolymer having a carboxyl group obtained by polymerization in the presence of the copolymer and having a weight average molecular weight of 10,000 to 100,000, and two or more reactive functionalities A pressure-sensitive adhesive composition comprising 0.03 to 3 parts by weight of a polyfunctional compound having a group is disclosed. However, the pressure-sensitive adhesive composition is a soft pressure-sensitive adhesive that relieves stress concentration caused by expansion and contraction of the optical film, and is excellent in suppressing white spots, but because the pressure-sensitive adhesive has insufficient cohesive force. In the process of the adhesive being dragged by the expansion and contraction of the optical film, peeling or foaming may occur, and the durability was insufficient. In particular, in a large-sized liquid crystal display device, the size of the optical film increases, and the shrinkage amount of the optical film increases accordingly. Therefore, it can be said that a soft adhesive that relaxes stress concentration has a great problem regarding durability.

  Also, as a method for suppressing white spots, on the contrary to the method for preventing the occurrence of white spots by relaxing the stress concentration, an adhesive having a high cohesive force is used to minimize the area where stress is generated. There is a method of suppressing the occurrence of white spots by holding down (for example, JP-A-2006-235568 (Patent Document 2)). However, in this method, since the pressure-sensitive adhesive has a high cohesive force, the pressure-sensitive adhesive force between the adherend and the optical film tends to be high, and the reworkability is poor.

  JP-A-9-80230 (Patent Document 3) discloses an acrylic pressure-sensitive adhesive containing at least one of polyether-modified silicone oil, silazane and silylamine as a pressure-sensitive adhesive having improved durability and reworkability. Is disclosed. However, the addition of a polyether-modified silicone oil or the like decreases the adhesiveness between the pressure-sensitive adhesive and the adherend, and is sufficiently predicted to be inferior in durability.

  As described above, it is difficult to satisfy both conflicting durability and reworkability and suppression of white spots, and it cannot be said that durability, reworkability and suppression of white spots have been sufficiently achieved.

JP 2004-331697 A JP 2006-235568 A Japanese Patent Laid-Open No. 9-80230

  The present invention is excellent in durability even in a high temperature or high temperature and high humidity environment, suppresses white spots, and can easily be reworked when an optical film is required to be re-attached, and the adhesive. It aims at providing the optical film which has an adhesive layer.

As a result of intensive studies to solve the above problems, the present inventors have found that an acrylic copolymer (A) containing a reactive functional group, an isocyanate compound (B), and a polyether-modified silicone (C). And it discovered that the said subject could be solved by using the adhesive formed from the adhesive composition containing a silane coupling agent (D). That is, the present invention has the following configuration in order to solve the above problems.
(1) 5 to 30 parts by weight of an isocyanate compound (B) and 0.05 parts by weight per 100 parts by weight of the acrylic copolymer (A) containing a reactive functional group and the acrylic copolymer (A); A pressure-sensitive adhesive composition containing ˜1 part by weight of a polyether-modified silicone (C) and 0.03 to 1 part by weight of a silane coupling agent (D).
(2) An acrylic copolymer (E) containing a reactive functional group, which is different from the acrylic copolymer (A), further comprising an isocyanate compound (B), a polyether-modified silicone (C), and a silane cup A ring agent (D) is an adhesive composition as described in said (1) formed by containing with respect to 100 weight part of mixtures of an acrylic copolymer (A) and an acrylic copolymer (E).
(3) In the above (1) or (2), the elongation at break in the tensile test at 25 ° C. is 300% to 1500%, and the 200% modulus is 0.15 N / mm ^{2 to 5} N / mm ^2. A pressure-sensitive adhesive comprising the pressure-sensitive adhesive composition described above.
(4) An optical film having a pressure-sensitive adhesive layer formed from the pressure-sensitive adhesive composition as described in (1) or (2) above.
(5) An optical film having a layer made of the pressure-sensitive adhesive as described in (3) above.

  According to the pressure-sensitive adhesive composition, pressure-sensitive adhesive, and optical film having the pressure-sensitive adhesive layer according to the present invention, excellent durability even in a high-temperature or high-temperature and high-humidity environment, and re-sticking of the optical film is required Can provide an optical film having an adhesive composition, an adhesive, and an adhesive layer that can be easily reworked and suppress white spots.

  The pressure-sensitive adhesive composition according to the embodiment of the present invention includes an acrylic copolymer containing a reactive functional group-containing monomer as a copolymerization component, an isocyanate compound (B), and a polyether-modified silicone (C). And a silane coupling agent (D). The pressure-sensitive adhesive composition according to this embodiment contributes to the reaction between the reactive functional group of the acrylic copolymer and the reactive functional group of the acrylic copolymer as well as the crosslinking reaction of the isocyanate compound (B). The isocyanate group that was not reacted reacts with water in the environment to form a multimer, and is considered to have good adhesive properties.

  In the present embodiment, the acrylic copolymer (A) is an acrylic acid ester monomer or a methacrylic acid ester monomer (hereinafter referred to as “acryl”) as a copolymerization component in the copolymer. When referring to a word including “methacryl”, it may be described as “(meth) acryl”), which means a copolymer containing 80% by weight or more, and containing 90% by weight or more of a copolymer component Preferred is a copolymer.

  The (meth) acrylic acid ester monomer is not particularly limited as long as it is a monomer having 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) acrylate, i-nonyl (meth) acrylate, n-decyl (meth) acrylate, n-dodecyl (meth) acrylate, stearyl (meth) acrylate and other (meth) acrylic acid straight chain having 1 to 18 carbon atoms or Branched alkyl esters, and one or more of these various derivatives It is possible to have.

In the acrylic copolymer (A) according to the present embodiment, a monomer other than the (meth) acrylate monomer is used as a copolymerization component within a range not exceeding the definition of the acrylic copolymer (A). Can be contained. 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 copolymer (A) according to the present embodiment contains a reactive functional group-containing monomer as a copolymerization component. The (meth) acrylic acid ester monomer having a reactive functional group is also included as a copolymer component of the acrylic copolymer (A) when defining the acrylic copolymer. Counted as the amount of ester monomer.

  Examples of reactive functional group-containing monomers include carboxyl group-containing monomers, hydroxyl group-containing monomers, glycidyl group-containing monomers, amide group-containing monomers, N-substituted amide group-containing monomers, One type or two or more types of tertiary amino group-containing monomers 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 the amide group-containing monomer and N-substituted amide group-containing monomer include acrylamide, methacrylamide, N-methyl (meth) acrylamide, N-ethyl (meth) acrylamide, and N-methoxymethyl (meth) acrylamide. N-ethoxymethyl (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 reactive functional groups as a copolymer component, in particular, a carboxyl group-containing monomer, or a carboxyl group-containing monomer and a hydroxyl group-containing monomer is an acrylic copolymer. It is preferable to be contained in the coalescence (A).

The proportion of the carboxyl group-containing monomer as a copolymer component is 0 with respect to the acrylic copolymer (A) for the purpose of improving the cohesive strength of the pressure-sensitive adhesive and the adhesion to the adherend. .5% by weight or more, preferably 1% by weight or more. The proportion of the carboxyl group-containing monomer as a copolymerization component is 5% by weight or less based on the acrylic copolymer (A) for the purpose of suppressing the adhesive force of the adhesive from becoming too high. Preferably it is 3 weight% or less.

  The proportion of the hydroxyl group-containing monomer as the copolymer component is increased in the acrylic copolymer (A) for the purpose of increasing the cohesive force of the pressure-sensitive adhesive composition and improving the durability of the pressure-sensitive adhesive composition. On the other hand, it is 0.001% by weight or more, preferably 0.01% by weight or more. Moreover, the ratio in which a hydroxyl-containing monomer is contained as a copolymerization component is 1 with respect to an acrylic copolymer (A) for the purpose of suppressing that an adhesive composition peels off with durability. % By weight or less, preferably 0.5% by weight or less.

  The weight average molecular weight (Mw) of the acrylic copolymer (A) is not less than 1 million, preferably not less than 1.2 million for the purpose of giving sufficient cohesive force to the pressure-sensitive adhesive composition and suppressing the generation of bubbles. Particularly preferably, it is made 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) above 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 point (Tg) of the acrylic copolymer (A) is −80 ° C. or higher, preferably −60 for the purpose of giving the adhesive composition sufficient cohesive force and exhibiting sufficient durability. Make it over ℃. In addition, the glass transition point (Tg) of the acrylic copolymer (A) is to exhibit sufficient adhesion to the support substrate in the pressure-sensitive adhesive composition, and to exhibit durability that does not cause peeling. -20 ° C or lower, preferably -30 ° C or lower.

The glass transition point (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 are the glass transition points of homopolymers of component 1, component 2, component 3,.
K). Moreover, in formula, M1, M2, M3 ... and Mn show the mole fraction of various components.

  The polymerization method of the acrylic copolymer (A) used in the present embodiment is not particularly limited and can be polymerized by methods such as solution polymerization, emulsion polymerization, suspension polymerization and the like. In addition, when manufacturing the adhesive composition which concerns on this Embodiment using the mixture of the copolymer obtained by superposition | polymerization, the process is comparatively simple and the solution which can obtain an adhesive composition in a short time It is preferable to polymerize by polymerization.

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

The pressure-sensitive adhesive composition according to the present embodiment may further contain an acrylic copolymer (E) different from the acrylic copolymer (A). The pressure-sensitive adhesive composition according to this embodiment uses a mixture of an acrylic copolymer (A) and an acrylic copolymer (E) as a resin component to adjust cohesive force and viscosity in a well-balanced manner. I can do it.

As a copolymerization component of the acrylic copolymer (E) according to the present embodiment, (meth) acrylic acid ester, a monomer having a reactive functional group, and an acrylic copolymer as another monomer The thing similar to what was illustrated by (A) can be used.

Of the monomers having various reactive functional groups as the copolymer component, it is preferable to include a carboxyl group-containing monomer and a hydroxyl group-containing monomer in the acrylic copolymer (E) as a copolymer component. The acrylic copolymer (E) has a high cohesive force by including a carboxyl group-containing monomer and a hydroxyl group-containing monomer as a copolymerization component, and it is easy to adjust the cohesion force and viscosity of the resin component. Become.

The proportion of the carboxyl group-containing monomer as a copolymerization component is relative to the acrylic copolymer (E) for the purpose of increasing the cohesive force of the adhesive and improving the durability of the adhesive composition. 0.1 wt% or more, preferably 0.3 wt% or more, particularly preferably 0.5 wt% or more. The proportion of the carboxyl group-containing monomer as a copolymer component is 5% by weight with respect to the acrylic copolymer (E) for the purpose of suppressing the adhesive force of the pressure-sensitive adhesive composition from becoming too high. The amount is preferably 3% by weight or less, particularly preferably 2% by weight or less.

The proportion of the hydroxyl group-containing monomer as a copolymerization component is 0.01% by weight or more, preferably 0.1% with respect to the acrylic copolymer (E) for the purpose of suppressing white spots. % By weight or more, more preferably 0.3% by weight or more. The proportion of the hydroxyl group-containing monomer as a copolymerization component is preferably 5% by weight or less based on the acrylic copolymer (E) for the purpose of suppressing the occurrence of peeling in the durability test. Is 3% by weight or less, particularly preferably 1% by weight or less.

The weight average molecular weight (Mw) of the acrylic copolymer (E) according to the present embodiment is 1 million or more, preferably 1.2 million or more, particularly for the purpose of giving sufficient cohesive force to the pressure-sensitive adhesive composition. Preferably it is set to 1.4 million or more. Moreover, the weight average molecular weight (Mw) of an acrylic copolymer (E) shall be 2.5 million or less for the purpose of ensuring the coating workability | operativity of an adhesive composition.

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

The polymerization method of the acrylic copolymer (E) used in the present embodiment is not particularly limited, and the polymerization can be performed by the same method as that of the acrylic copolymer (A). In the production of the pressure-sensitive adhesive composition according to the present 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. Is preferred.

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. In addition, the weight average molecular weight of the acryl-type copolymer (E) based on this Embodiment can be made into a desired molecular weight by adjusting reaction temperature, time, the amount of solvents, and the kind and quantity of a catalyst.

The difference between the solubility parameter of the acrylic copolymer _(A) (SP A) and acrylic copolymer solubility parameter (SP _E) of _{(E) (ΔSP = SP A} -SP E) -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 (E) is extremely excellent.

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

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

The pressure-sensitive adhesive composition according to this embodiment is 100 parts by weight of the acrylic copolymer (A) or 100 parts by weight of a mixture of the acrylic copolymer (A) and the acrylic copolymer (E). On the other hand, it contains 5 to 30 parts by weight of the isocyanate compound (B).

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

Examples of the isocyanate compound (B) include “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" (Asahi Kasei Corporation), "Takenate D-110N", "Takenate D-120N", "Takenate M-631N" Commercially available products such as “MT-Oresta-NP1200” (manufactured by Mitsui Chemicals Polyurethane Co., Ltd.) can be suitably used.

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

The amount of the isocyanate compound (B) used relative to 100 parts by weight of the acrylic copolymer (A) or 100 parts by weight of the mixture of the acrylic copolymer (A) and the acrylic copolymer (E) is blank. In order to suppress this, the amount is 5 parts by weight or more, preferably 10 parts by weight or more. The amount of the isocyanate compound (B) used relative to 100 parts by weight of the acrylic copolymer (A) or a mixture of the acrylic copolymer (A) and the acrylic copolymer (E) is as follows. For the purpose of securing the compatibility between the polymer and the isocyanate compound (B) and generating a sufficient tackiness as an adhesive, the amount is 30 parts by weight or less, preferably 20 parts by weight or less.

  Moreover, the pressure-sensitive adhesive composition according to the present embodiment forms a multimer by reacting the isocyanate group of the isocyanate compound (B) that does not contribute to the reaction with the acrylic copolymer with water in the environment, It seems to show good adhesive properties with excellent durability and suppression of white spots. Reactivity between isocyanate groups and water is relatively high, and some isocyanate groups will react with water in the environment without adding an excessive amount of isocyanate groups to the reactive functional groups of the acrylic copolymer. In order to improve the durability and suppression of white spots, a total of 1 equivalent of reactive functional groups of the acrylic copolymer is considered to form a multimer. The isocyanate group is used in an amount of more than 1 equivalent, preferably 1.01 equivalent or more, particularly preferably 1.2 equivalent or more.

  The pressure-sensitive adhesive composition according to the present 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 to form a crosslinked structure, and is not limited to an aziridine compound, an epoxy compound, a melamine formaldehyde condensate, Examples thereof include metal salts and metal chelate compounds. Moreover, it is preferable to use an aziridine compound and an epoxy compound from a viewpoint of the adhesiveness of an optical film and an adhesive, and durability. These crosslinking agents can be used alone or in combination of two or more.

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” [more 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, Particular preference is given to using N ′, N′-tetraglycidyl-m-xylylenediamine. As such an epoxy compound, for example, those commercially available under trade names such as “TETRAD-C” and “TETRAD-X” (manufactured by Mitsubishi Gas Chemical Co., Inc.) can be suitably used.

The pressure-sensitive adhesive composition according to this embodiment is 100 parts by weight of the acrylic copolymer (A) or 100 parts by weight of a mixture of the acrylic copolymer (A) and the acrylic copolymer (E). On the other hand, 0.05 to 1 part by weight of polyether-modified silicone (C) is contained. As the polyether-modified silicone (C), both ends, one end, side chain of dimethylpolysiloxane, or a part of methyl groups at both ends and side chain are represented by -R (C ₂ H ₄ O) _a (C ₃ H ₆ O) _b R ′ substituted (wherein R is an alkylene group having 1 or more carbon atoms, R ′ is a hydrogen atom or an alkyl group having 1 or more carbon atoms, a and b are integers of 0 or more and a + b> In the case of a copolymer of ethylene oxide and propylene oxide, either a block or a random copolymer may be used.) A linear block copolymer of dimethylpolysiloxane and polyoxyalkylene. One type or two or more types can be used.

Examples of such polyether-modified silicone (C) 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”, “K -341 "," KP-118 "," F-501 "," X-22-3506 "," X-22-3004 "," KF-6005 "," KP-101 "," KF-889 " “KF-6003”, “X-22-4515”, “F-3031”, “X-24-1430”, “X-22-4991”, “KP-208” (manufactured by Shin-Etsu Chemical Co., Ltd.) , “L-720”, “L-7604”, “Y-7006”, “BY-16-201”, “FZ-77”, “FZ-2101”, “FZ-2104”, “FZ-2110” , “FZ-2118”, “FZ-2120”, “FZ-2122”, “FZ-2130”, “FZ-2161”, “FZ-2162”, “FZ-2163”, “FZ-2164”, “ FZ-2166 "," FZ-2191 "," FZ-2 54 "," FZ-2203 "," FZ-2207 "," FZ-2208 "," L-7001 "," L-7002 "," SF-8427 "," SF-8428 "," SH-3749 " , “SH-3773M”, “SH-8400”, “FZ-5609”, “FZ-7001”, “FZ-7002” (manufactured by Toray Dow Corning), “TSF-4440”, “TSF- “4441”, “TSF-4445”, “TSF-4446”, “TSF-4450”, “TSF-4442”, “TSF-4460” [Momentive Performance Materials Japan Ltd.] What is marketed can be used suitably.

The amount of the polyether-modified silicone (C) used is 100 parts by weight of the acrylic copolymer (A) or 100 parts by weight of the mixture of the acrylic copolymer (A) and the acrylic copolymer (E). For the purpose of suppressing the adhesive strength of the pressure-sensitive adhesive and the increase in adhesive strength over time, the content is 0.05 parts by weight or more, preferably 0.1 parts by weight or more. Moreover, the usage-amount of polyether modified silicone (C) with respect to 100 weight part of acrylic copolymers (A) or a mixture of acrylic copolymer (A) and acrylic copolymer (E) 100 weight parts. Is 1 part by weight or less, preferably 0.5 part by weight or less, particularly preferably for the purpose of maintaining good adhesion between the pressure-sensitive adhesive and the adherend and suppressing the occurrence of peeling in the durability test. Is 0.3 parts by weight or less.

  Further, depending on the purpose, silicone oils other than the polyether-modified silicone (C) may be appropriately combined.

The pressure-sensitive adhesive composition according to this embodiment is 100 parts by weight of the acrylic copolymer (A) or 100 parts by weight of a mixture of the acrylic copolymer (A) and the acrylic copolymer (E). On the other hand, 0.03 to 1 part by weight of the silane coupling agent (D) is contained. Examples of the silane coupling agent (D) include γ
A mercapto group-containing silane coupling agent such as mercaptopropyltrimethoxysilane, γ-mercaptopropyltriethoxysilane, γ-mercaptopropyldimethoxymethylsilane;
For example, β- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, β- (3,4-epoxycyclohexyl) ethyltriethoxysilane, methyltri (
Glycidyl) epoxy group-containing silane coupling agents such as silane, γ-glycidoxypropylmethyldimethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropyltriethoxysilane;
For example, 3-triethoxysilylpropyl succinic acid (anhydride), 3-trimethoxysilylpropyl succinic acid (anhydride), 3-methyldimethoxysilylpropyl succinic acid (
Carboxyl group-containing silane coupling agents such as methyl diethoxysilylpropyl succinic acid (anhydride), 1-carboxy-3-triethoxysilylpropyl succinic acid (anhydride);
-(Β-aminoethyl) -γ-aminopropylmethyldimethoxysilane, N- (β-aminoethyl) -γ-aminopropyltrimethoxysilane, N
-(Β-aminoethyl) -γ-aminopropyltriethoxysilane, γ-aminopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, N
An amino group-containing silane coupling agent such as phenyl-γ-aminopropyltrimethoxysilane; for example, a hydroxyl group-containing silane coupling agent such as γ-hydroxypropyltrimethoxysilane;
-One or more isocyanate group-containing silane coupling agents such as isocyanatepropyltrimethoxysilane can be used.

  Among the silane coupling agents (D), an epoxy group-containing silane coupling agent is particularly preferable because of its excellent durability at high temperature or high temperature and high humidity.

The content of the silane coupling agent (D) is an acrylic copolymer for the purpose of suppressing the generation of bubbles and the like due to peeling between the pressure-sensitive adhesive and the adherend at high temperature or high temperature and high humidity. (A) 100 parts by weight, or 0.03 parts by weight or more, preferably 0.05 parts by weight with respect to 100 parts by weight of a mixture of the acrylic copolymer (A) and the acrylic copolymer (E) That's it. The content of the silane coupling agent (D) is an acrylic copolymer (A) 100 for the purpose of suppressing a decrease in reworkability due to an increase in the adhesive strength of the adhesive due to a change with time of the adhesive. 1 part by weight or less, preferably 0 or less, 5 parts by weight or less, and particularly preferably 0 part by weight or 100 parts by weight of the mixture of acrylic copolymer (A) and acrylic copolymer (E). .3 parts by weight or less

  As described above, the polyether-modified silicone (C) and the silane coupling agent (D) are used in the pressure-sensitive adhesive composition according to the present embodiment.

When polyether-modified silicone (C) is included in the pressure-sensitive adhesive composition, the adhesiveness between the pressure-sensitive adhesive and the adherend is reduced, the initial pressure-sensitive adhesive force and the increase in pressure-sensitive adhesive strength over time are small, and reworkability is improved. An excellent pressure-sensitive adhesive can be obtained. However, the polyether-modified silicone (C) alone cannot withstand the expansion and contraction of the optical film under high temperature or high temperature and high humidity, peeled off, and has extremely poor durability.

When the silane coupling agent (D) is contained in the pressure-sensitive adhesive composition, the adhesiveness between the pressure-sensitive adhesive and the adherend is improved, and the durability is improved. However, the silane coupling agent (D) alone was inferior in reworkability because the adhesive strength of the adhesive increased with time.

  As described above, in the pressure-sensitive adhesive composition using only the polyether-modified silicone (C) and the silane coupling agent (D), it is difficult to achieve both durability and reworkability. However, by using the polyether-modified silicone (C) and the silane coupling agent (D) in a specific amount, the effect of adding the polyether-modified silicone (C) is mainly exhibited at the initial stage or over time. A pressure-sensitive adhesive composition having excellent reworkability and excellent durability can be obtained by mainly exhibiting the effect of addition of the silane coupling agent (D) at high temperature or high temperature and high humidity. Thus, a pressure-sensitive adhesive having good durability and reworkability can be obtained by using specific amounts of the polyether-modified silicone (C) and the silane coupling agent (D) in the pressure-sensitive adhesive composition.

  The pressure-sensitive adhesive composition according to the present embodiment includes the above-described acrylic copolymer (A), a mixture of the acrylic copolymer (A) and the acrylic copolymer (E), an isocyanate compound (B ), Polyether-modified silicone (C), silane coupling agent (D), cross-linking agent other than isocyanate compound (B), within the range not impairing the effects exhibited by the pressure-sensitive adhesive composition according to the present embodiment In various amounts, various additives, solvents, weather resistance stabilizers, tackifiers, plasticizers, softeners, dyes, pigments, inorganic fillers, and the like can be appropriately blended. The range of the blending amount of the weather resistance stabilizer, tackifier, plasticizer, softener, dye, pigment, inorganic filler, etc. is 100 parts by weight of acrylic copolymer (A) or acrylic copolymer (A ) And the acrylic copolymer (E) are preferably 30 parts by weight or less, more preferably 20 parts by weight or less, and most preferably 10 parts by weight or less based on 100 parts by weight of the mixture of the acrylic copolymer (E). By making the blending amount within such a range, the pressure-sensitive adhesive composition can appropriately maintain the balance of the adhesive strength, wettability, heat resistance, and paste transferability of the pressure-sensitive adhesive composition, and exhibits a variety of good physical properties. can get.

  The optical film according to the present embodiment is an optical film having a pressure-sensitive adhesive layer formed from the pressure-sensitive adhesive composition according to the present embodiment. As the manufacturing method, for example, a pressure-sensitive adhesive layer made of the pressure-sensitive adhesive composition according to the present embodiment is formed on a release sheet, and the resulting release sheet and pressure-sensitive adhesive layer are laminated on the pressure-sensitive adhesive side. A film is laminated to form a laminate of release sheet / adhesive layer / optical film. When laminating | stacking with adherends, such as a liquid crystal cell, it can create by peeling a peeling film from the laminated body, and pressing and adhere | attaching the peeled adhesive layer on the surface of adherends, such as a liquid crystal cell.

  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. A more specific method for forming the pressure-sensitive adhesive layer on the release sheet is a method of forming the pressure-sensitive adhesive composition according to this embodiment by applying the pressure-sensitive adhesive composition on the release sheet and drying it. 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.

  In the pressure-sensitive adhesive composition according to the present embodiment, the reactive functional group of the acrylic copolymer and the isocyanate compound (B) form a crosslinked structure, and the isocyanate group that has not contributed to the crosslinking reaction is water in the environment. It is thought that multimers are formed by reaction. The gel content after the formation of the cross-linked 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 giving sufficient cohesive force.

The gel content can be measured by the following method.
(Method for measuring 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.
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 optical film according to the present embodiment has an adhesive strength to an alkali-free glass plate after 24 hours at 23 ° C. and an adhesive strength to an alkali-free glass plate after 30 days at 23 ° C. after forming an adhesive layer. 0.5 to 10 N / 25 mm.

  When reworking is performed after the pressure-sensitive adhesive layer is formed on the optical film, the reworking is performed immediately, or the reworking is performed after being stored for a long time in a relatively good environment. The pressure-sensitive adhesive layer formed from the pressure-sensitive adhesive according to the present embodiment has an adhesive force with respect to an alkali-free glass plate after 30 days at 23 ° C., and can be easily reworked.

In the pressure-sensitive adhesive according to the present embodiment, the elongation at break in the tensile test of the pressure-sensitive adhesive after formation of the crosslinked structure and multimers is 300% to 1500%, and the 200% modulus is 0.15 N / mm. ^{2 to 5} N / mm ² . The elongation at break in the tensile test of the pressure-sensitive adhesive is set to 300% or more, preferably 400% or more, particularly preferably 500% or more for the purpose of suppressing peeling in durability. In addition, the elongation at break in the tensile test of the pressure-sensitive adhesive is 1500% or less, preferably 1000% or less for the purpose of suppressing foaming in durability. 200% modulus in a tensile test of the pressure-sensitive adhesive, for the purpose of suppressing the white spot, 0.15 N / mm ² or more, preferably 0.4 N / mm ² or more. Also, 200% modulus in a tensile test of the pressure-sensitive adhesive for the purpose of suppression of the peeling occurs in durability, 5N / mm ² or less, preferably 3N / mm ² or less, particularly preferably with 2N / mm ² or less .

In addition, the elongation at break and 200% modulus in the tensile test of the pressure-sensitive adhesive are values measured by the following measuring method.
(Measurement method of elongation at break and 200% modulus in tensile test of adhesive)
It measures according to following (1)-(5).
(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 thickness after drying was 25 μm, and a hot-air circulating dryer for 90 seconds at 100 ° C. To form a film-like pressure-sensitive adhesive.
(2) The formed pressure-sensitive adhesive layer is cured for 10 days in an environment of 23 ° C. and humidity 50% RH.
(3) The film-like pressure-sensitive adhesive obtained in (2) is cut out by 150 mm × 30 mm, and the pressure-sensitive adhesive layer is formed into a columnar shape having a width of 30 mm to prepare a test sample.
(4) Under an environment of 23 ° C., the test sample was subjected to a tensile test under conditions of a distance between chucks of 10 mm and a pulling speed of 100 mm / min, and a stress-strain curve was obtained.
(5) The amount of strain when the test sample broke was taken as the breaking elongation, and the value obtained by dividing the stress when the elongation was 200% by the initial cross-sectional area (3.75 mm ² ) was obtained as the 200% modulus.

(Effect of embodiment)
Since the optical film having the pressure-sensitive adhesive according to the present embodiment and the pressure-sensitive adhesive layer has the above-described configuration, the optical film is suppressed to a predetermined adhesive force for a long time with respect to the adherend. Excellent reworkability. In addition, since the pressure-sensitive adhesive according to the present embodiment and the optical film having the pressure-sensitive adhesive layer have a high cohesive force represented by 200% modulus, the occurrence of white spots is suppressed, and the 200% modulus is suppressed. Since it has a high cohesive force typified by and an appropriate viscosity typified by elongation, it is possible to suppress the occurrence of peeling and bubbles that usually occur at high temperatures or high temperatures and high humidity.

  Examples and comparative examples will be described below. In addition, preparation of the test piece used in the Example and the comparative example, various test methods, and the 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, a polarizing base film [polyvinyl alcohol (
PVA) film with a cellulose triacetate (TAC) film laminated on both sides of a polarizer (about 190 μm) on both sides of a polarizer; After crimping, 23 ° C, 50% RH
A polarizing film having an adhesive layer was obtained by curing for 10 days.

(2) Measurement of adhesive strength (2-1) Measurement of adhesive strength after standing for 24 hours in an environment of 23 ° C. The polarizing film prepared in “(1) Preparation of optical film for test” was cut into 25 mm × 150 mm. Then, this polarizing film piece was pressure-bonded to a non-alkali glass plate “# 1737” manufactured by Corning, Inc. using a desktop laminating machine to obtain a test sample. 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 50% RH, and then the adhesive strength at 180 ° peeling (peeling speed: 300 mm / min) was measured. In the embodiments and examples of the present invention, “adhesive strength to an alkali-free glass plate after 24 hours at 23 ° C. after forming an adhesive layer” means the adhesive strength measured by this test method. means.

(2-2) Measurement of adhesive strength after standing for 30 days in an environment of 23 ° C. Prepared in the same manner as “(2-1) Measurement of adhesive strength after standing in an environment of 23 ° C.” and autoclaved. The test sample was allowed to stand for 30 days under conditions of 23 ° C. and 50% RH, and then the adhesive strength at 180 ° peeling (peeling speed: 300 mm / min) was measured. In the embodiments and examples of the present invention, “adhesive strength against an alkali-free glass plate after 30 days at 23 ° C. after forming an adhesive layer” means the adhesive strength measured by this test method. means.

(3) Evaluation of reworkability Adhesive strength to an alkali-free glass plate after 30 days at 23 ° C. measured in “(2-2) Measurement of adhesive strength after standing for 30 days in an environment of 23 ° C.” The adhesive residue on the alkali-free glass plate was visually observed and evaluated. The evaluation criteria are as follows.
A: 8 N / 25 mm or less, and no adhesive remains on the alkali-free glass plate.
A: Greater than 8 N / 25 mm and 10 N / 25 mm or less, and no adhesive remains on the alkali-free glass plate.
X: Larger than 10 N / 25 mm, or the adhesive remains on the non-alkali glass plate.

(4) Evaluation of durability 140 mm obtained by cutting the polarizing film prepared in “(1) Preparation of optical film for test” so that the long side is 45 ° with respect to the absorption axis.
X A test piece of 260 mm (12 inches) was used and affixed 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 left for 24 hours at 23 ° C. and 50% 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 hardly seen.
X: Foaming is noticeable.
b) Peeling ◎: On the four sides, there is no peeling at the position of the outer peripheral edge.
◯: 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.

(5) Evaluation test of white spot phenomenon A polarizing film having an adhesive layer of the same size as “(4) Durability evaluation” is polarized on both surfaces of a 0.7 mm Corning non-alkali glass plate “# 1737”. A test sample was prepared so that the axes were perpendicular to each other. 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. Then, it was left to stand at 80 ° C. under dry conditions for 500 hours. After standing, a uniform light source was used under conditions of 23 ° C. and 50% RH, and the white spot state was visually observed. 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, n-butyl acrylate (BA) 98.975 parts by weight, acrylic acid (AA) 1 part by weight, 2-hydroxyethyl acrylate (2HEA ) 0.025 parts by weight, ethyl acetate (EAc) 100 parts by weight, and azobisisobutyronitrile (AIBN) 0.1 part by weight were added, and the air in the reaction vessel was replaced with nitrogen gas. Thereafter, the temperature of the contents of the reaction vessel was raised to 65 ° C. and reacted for 8 hours in a nitrogen atmosphere under stirring. After completion of the reaction, the reaction mixture was diluted with ethyl acetate to obtain an acrylic copolymer solution having a solid content of 19.2% by weight. The weight average molecular weight of the acrylic polymer was 1.52 million.

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

(Production of pressure-sensitive adhesive composition for polarizing plate)
Example 1
469 parts by weight of the acrylic copolymer solution synthesized in Production Example 1 as the acrylic copolymer (A) (90 parts by weight as the acrylic copolymer (A)), and the production example as the acrylic copolymer (E) 51 parts by weight of the acrylic copolymer solution synthesized in 3 (10 parts by weight as the acrylic copolymer (E)), and 20 parts by weight of coronate L as the isocyanate compound (B) (isocyanate compound by Nippon Polyurethane, active ingredient 15) Parts by weight), 0.27 parts by weight of SH-3773M as polyether-modified silicone (C) (polyether-modified silicone oil by Toray Dow Corning Co., Ltd., 0.2 parts by weight of active ingredient), KBM as silane coupling agent (D) -403 0.1 parts by weight (Shin-Etsu Chemical Co., Ltd. silane coupling agent, active ingredient 0.1 parts by weight) A pressure-sensitive adhesive composition was obtained. The amount of isocyanate groups (described as “NCO / resin functional group” in Table 2) with respect to a total of 1 equivalent of reactive functional groups of the acrylic copolymer (A) and the acrylic copolymer (E) is 4.32. Equivalent. Using the obtained pressure-sensitive adhesive composition, various tests were conducted according to the measurement method for the gel, the elongation at break, and the measurement method for 200% modulus. The results are shown in Table 2. Furthermore, using the obtained pressure-sensitive adhesive composition, a test optical film was prepared by the above-described test optical film preparation method, the above-described various measurements were performed, and the results are shown in Table 3.

(Examples 2-7, Comparative Examples 1-3)
A pressure-sensitive adhesive composition (adhesives according to Examples 2 to 7) was used in the same manner as in Example 1 except that the compounding compositions of Examples and Comparative Examples shown in Table 2 were used instead of the compounding composition in Example 1. Adhesive compositions and pressure-sensitive adhesive compositions according to Comparative Examples 1 to 3). Using the obtained pressure-sensitive adhesive composition, various tests were conducted according to the measurement method for the gel, the elongation at break, and the measurement method for 200% modulus. The results are shown in Table 2. Furthermore, using the obtained pressure-sensitive adhesive composition, a test optical film was prepared by the above-described test optical film preparation method, the above-described various measurements were performed, and the results are shown in Table 3.

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

In addition, the symbol of each compound in Table 2 is as follows, and the addition amount of each component is a weight part of an active ingredient.
(A) Coronate L “Isocyanate compound manufactured by Nippon Polyurethane Co., Ltd.”
Product name: Coronate L, 75% active ingredient
Trimethylolpropane modified tolylene diisocyanate isocyanate compound (B) component (b) TETRAD-X "Epoxy compound manufactured by Mitsubishi Gas Chemical Company"
Product name: TETRAD-X, 100% by weight of active ingredient
Chemical name: N, N, N ′, N′-tetraglycidyl-m-xylenediamine epoxy compound (c) SH-3773M “Polyether-modified silicone manufactured by Toray Dow Corning”
Product name: SH-3773M, active ingredient 100%,
Polyether-modified silicone (C) component (d) KBM-403 “Silane coupling agent manufactured by Shin-Etsu Chemical Co., Ltd.”
Product name: KBM-403, 100% active ingredient
Chemical name; 3-glycidoxypropyltrimethoxysilane,
Silane coupling agent (D) component

  As can be seen by referring to Table 3, all the optical films according to Examples 1 to 7 are in all items of reworkability, durability (80 ° C.), durability (60 ° C. × 90% RH), and white spots. Evaluation criteria indicated “「 ”or“ 「”. That is, the optical films according to Examples 1 to 7 are excellent in durability even in a high temperature or high temperature and high humidity environment and can suppress white spots, and can easily be reworked when reattachment of the optical film is required. Indicated.

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

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

Claims (5)

  5 to 30 parts by weight of the isocyanate compound (B) and 0.05 to 100 parts by weight of the acrylic copolymer (A) containing a reactive functional group and 100 parts by weight of the acrylic copolymer (A). A pressure-sensitive adhesive composition containing 1 part by weight of a polyether-modified silicone (C) and 0.03 to 1 part by weight of a silane coupling agent (D).   Further comprising an acrylic copolymer (E) containing a reactive functional group different from the acrylic copolymer (A), the isocyanate compound (B), the polyether-modified silicone (C), the silane The pressure-sensitive adhesive composition according to claim 1, wherein the coupling agent (D) is contained with respect to 100 parts by weight of a mixture of the acrylic copolymer (A) and the acrylic copolymer (E). The pressure-sensitive adhesive composition according to claim 1 or 2, wherein the elongation at break in a tensile test at 25 ° C is 300% to 1500%, and the 200% modulus is 0.15 N / mm ^{2 to 5} N / mm ² . A pressure sensitive adhesive.   An optical film having a pressure-sensitive adhesive layer formed from the pressure-sensitive adhesive composition according to claim 1.   The optical film which has a layer which consists of an adhesive of Claim 3.