JP5765303B2 - Optical pressure-sensitive adhesive composition - Google Patents

Description

  The present invention relates to an optical pressure-sensitive adhesive composition using a novel adhesion modifier. More specifically, it can be peeled at the time of manufacturing a liquid crystal display device, but its adhesiveness increases with time, and when used under high-temperature and high-humidity conditions, it exhibits excellent durability, such as a liquid crystal element. The present invention relates to an adhesive composition.

  The liquid crystal element includes two glass substrates in which transparent electrodes are disposed on the surface in contact with the liquid crystal, a liquid crystal material filled between the two glass substrates, and a polarization disposed on the outer surface of the two substrates. It consists of a laminated plate of a plate or a polarizing plate and a retardation plate. In such a liquid crystal element, a polarizing plate or a laminated plate of a polarizing plate and a retardation plate is attached to the surface of a glass substrate using an acrylic resin-based pressure sensitive adhesive, for example.

  In the manufacturing process of the liquid crystal element using such a pressure sensitive adhesive, when a problem occurs in the bonding between the polarizing plate or the laminated plate of the polarizing plate and the retardation plate and the glass substrate, the polarizing plate or the polarizing plate If the laminated plate with the retardation plate is peeled off from the glass substrate and a new polarizing plate or a laminated plate of the polarizing plate and the retardation plate can be attached to the glass substrate again, an expensive liquid crystal material and this liquid crystal material A liquid crystal element exhibiting good liquid crystal performance can be produced without discarding the filled cells themselves. From such a viewpoint, it is desirable that the pressure-sensitive adhesive is easily peeled off when a failure occurs at the stage of bonding the polarizing plate or the laminated plate of the polarizing plate and the retardation plate to the glass substrate. .

  On the other hand, in recent years, the use range of liquid crystal elements such as personal computers, in-vehicle liquid crystal monitors, television screens, etc. has been remarkably wide, and the usage environment of liquid crystal elements has become extremely severe as various applications have spread. Yes. Therefore, it is desirable that the adhesive strength between the polarizing plate or the laminated plate of the polarizing plate and the retardation plate and the glass substrate is higher so as to withstand such use conditions, and that the high adhesive strength does not change for a long time. It is done.

  As described above, the pressure-sensitive adhesive used for adhering the polarizing plate or the laminated plate of the polarizing plate and the retardation plate to the glass substrate of the liquid crystal element is liquid crystal when it is going to be peeled off when a malfunction occurs in the manufacturing process. After the polarizing plate or the laminated plate of the polarizing plate and the retardation plate can be easily peeled from the glass substrate without damaging the device, on the other hand, after the liquid crystal device is actually used and used for various applications Therefore, the contradictory properties that a stable adhesive strength is maintained over a long period of time are required.

  Conventionally, an acrylic resin system in which an acrylic / silicone-based graft copolymer composed of a backbone polymer composed of an acrylic polymer and a branched polymer composed of an organopolysiloxane grafted on the backbone polymer is used as an adhesive modifier. Pressure-sensitive adhesive can easily peel off a polarizing plate or a laminate of a polarizing plate and a retardation plate from a glass substrate without causing damage to the liquid crystal device when a failure occurs in the manufacturing stage of the liquid crystal device. For example, Japanese Patent Application Laid-Open No. 3-8131 (Patent Document 1) discloses that a stable adhesive strength is maintained for a long time after a liquid crystal element is actually used in various applications. ing. However, since such a conventionally known acrylic / silicone graft copolymer has poor adhesion to a glass substrate, the stability of adhesive strength over a long period of time under the severe environment demanded in recent years is It is still insufficient and improvements are required.

Japanese Patent Laid-Open No. 3-8131

  The present invention responds to the above-mentioned demand, and is an optical pressure-sensitive material suitable for adhesion between optical members, particularly for adhesion between a glass substrate in a liquid crystal element and a polarizing plate, or a laminated plate of a polarizing plate and a retardation plate. An object is to provide an adhesive composition.

  As a result of intensive studies to achieve the above object, the present inventors have found that acrylic / silicone graft copolymers having hydrolyzable silyl groups, which are radical copolymers of the following components (a) to (d): The pressure-sensitive adhesive composition in which the polymer is added to the acrylic polymer to provide an excellent effect as an adhesive modifier, and the acrylic / silicone graft copolymer is blended with the acrylic polymer constitutes the liquid crystal element. A polarizing plate or a laminated plate of a polarizing plate and a retardation plate can be securely bonded to a glass substrate with an appropriate strength, and the polarizing plate or the laminated plate of the polarizing plate and the retardation plate is peeled off in the production process. When the need arises, it can be peeled off without damaging the liquid crystal cell such as a glass substrate, and the adhesive does not easily remain on the glass substrate. After being subjected to the actual use of perceives to be able to maintain a stable firm adhesion strength long term, leading to the completion of the present invention.

（式中、Ｒ⁴は水素原子又はメチル基、Ｒ⁵は酸素原子が介在してもよい炭素原子数１〜１２の２価炭化水素基、Ｒ⁶はメチル基又はトリメチルシロキシ基、Ｒ⁷は炭素原子数１〜４の１価炭化水素基であり、ｂは平均重合度を示す０〜２００の数、ｃは１〜３の整数である。）
〔４〕 上記（ｃ）成分が、下記一般式（３）で表されるポリオキシアルキレン化合物であり、５〜２０質量％の割合で含有する〔１〕〜〔３〕のいずれかに記載の光学用感圧接着剤組成物。

（式中、Ｒ⁸は水素原子又はメチル基、Ｒ⁹は炭素原子数１〜４の１価炭化水素基又はアセチル基であり、ｄは平均で２≦ｄ≦３を満足する数、ｅは平均重合度を示す２〜１００の数である。）
〔５〕 上記（ｄ）成分がエポキシ官能基を有するアクリル系モノマーを含み、５〜８０質量％の割合で含有する〔１〕〜〔４〕のいずれかに記載の光学用感圧接着剤組成物。 Specifically, the present invention provides the following optical pressure-sensitive adhesive composition.
[1] (A) 100 parts by mass of an acrylic polymer;
(B) Adhesive modification comprising a radical copolymer of the following components (a), (b), (c) and (d), comprising an acrylic / silicone graft copolymer having a hydrolyzable silyl group An optical pressure-sensitive adhesive composition containing 0.01 to 10 parts by mass of an agent.
(A) 1 to 60% by mass of an organopolysiloxane compound having one radical polymerizable group in one molecule;
(B) 5 to 40% by mass of a radical polymerizable organic silicon compound represented by the following formula (1)
X—R ¹ —SiR ² _3-a (OR ³ ) _a (1)
(In the formula, X is a radically polymerizable group, R ¹ is a divalent hydrocarbon group having 1 to 12 carbon atoms or a single bond in which an oxygen atom may be interposed, and R ² and R ³ each have 1 to 1 carbon atoms. 4 is a monovalent hydrocarbon group, and a is an integer of 1 to 3.)
(C) 0 to 30% by mass of a polyoxyalkylene compound having one radical polymerizable group in one molecule,
(D) Acrylic monomer (however, excluding those corresponding to the above components (a), (b), (c)) 0 to 94% by mass
(However, the total of the components (a), (b), (c) and (d) is 100% by mass).
[2] The acrylic polymer of the component (A) is an acrylic monomer having no organic functional group of 60 to 99% by mass, an acrylic monomer having an organic functional group of 1 to 20% by mass, and copolymerized with these monomers. Other possible monomers (excluding those corresponding to the components (a), (b) and (c) above) are 0 to 20% by mass, and the total of these three monomers is 100% by mass. The optical pressure-sensitive adhesive composition according to [1], which is a copolymer.
[3] The optical pressure-sensitive adhesive composition according to [1] or [2], wherein the component (a) is an organopolysiloxane compound represented by the following general formula (2).

(Wherein R ⁴ is a hydrogen atom or a methyl group, R ⁵ is a C 1-12 divalent hydrocarbon group in which an oxygen atom may be interposed, R ⁶ is a methyl group or a trimethylsiloxy group, R ⁷ is (It is a monovalent hydrocarbon group having 1 to 4 carbon atoms, b is a number of 0 to 200 indicating the average degree of polymerization, and c is an integer of 1 to 3).
[4] The component (c) is a polyoxyalkylene compound represented by the following general formula (3), and is contained in a proportion of 5 to 20% by mass [1] to [3] Optical pressure-sensitive adhesive composition.

(Wherein R ⁸ is a hydrogen atom or a methyl group, R ⁹ is a monovalent hydrocarbon group or an acetyl group having 1 to 4 carbon atoms, d is a number satisfying 2 ≦ d ≦ 3 on average, and e is It is a number from 2 to 100 indicating the average degree of polymerization.)
[5] The optical pressure-sensitive adhesive composition according to any one of [1] to [4], wherein the component (d) includes an acrylic monomer having an epoxy functional group and is contained in a proportion of 5 to 80% by mass. object.

The optical pressure-sensitive adhesive composition of the present invention can adhere a glass substrate and a polarizing plate or a laminated plate of a polarizing plate and a retardation plate with necessary and sufficient adhesive strength in the production process of a liquid crystal element. it can. In the production process, the adhesive strength is not excessively high even when the adhesive composition is subjected to heating or the like, and is maintained at an appropriate level. For this reason, if there is a problem in bonding in the manufacturing process, the polarizing plate or the laminated plate of the polarizing plate and the retardation plate can be easily peeled off from the glass substrate, and in that case, the adhesive remains on the substrate. However, it is rare that the glass substrate or the liquid crystal cell is damaged during peeling.
Furthermore, the pressure-sensitive adhesive composition of the present invention exhibits appropriate adhesiveness and peelability as described above in the manufacturing process of the liquid crystal element, while the completed liquid crystal element is actually used for various applications. Even if exposed to harsh conditions such as high temperature and high humidity, the necessary and sufficient adhesive strength is stably maintained over a long period of time, such as swelling or peeling on the polarizing plate or a laminate of the polarizing plate and the retardation plate. Adhesion failure is unlikely to occur.

The optical pressure-sensitive adhesive composition of the present invention will be specifically described below.
The optical pressure-sensitive adhesive composition of the present invention comprises (A) an acrylic polymer as a main component, and (B) a specific acrylic / silicone graft copolymer having a hydrolyzable silyl group as an adhesive modifier. Contains coalescence. Hereinafter, description will be made sequentially.

[(A) Acrylic polymer]
The acrylic polymer as component (A) has an effect of imparting pressure-sensitive adhesiveness to the composition of the present invention.

  In the present invention, the “acrylic polymer” is a polymer of an acrylic monomer (that is, a homopolymer and a copolymer). Acrylic monomers include acrylic acid monomers and methacrylic acid monomers. Examples of the acrylic acid monomer include acrylic acid, acrylic acid ester, and acrylamide. Examples of the acrylate esters include alkyl acrylate esters such as methyl acrylate, ethyl acrylate, and butyl acrylate. Examples of the methacrylic acid monomer include methacrylic acid, methacrylic acid ester, and methacrylamide. Examples of methacrylic acid esters include methacrylic acid alkyl esters such as methyl methacrylate, ethyl methacrylate, and butyl methacrylate.

  In this specification, terms such as “(meth) acrylic acid” and “(meth) acrylate” are respectively used as a general concept of acrylic acid and methacrylic acid and a general concept of acrylate and methacrylate.

  The acrylic polymer used in the present invention may be a single polymer of the above monomers or a copolymer of two or more monomers. Among these, a copolymer containing an acrylic monomer having no organic functional group and an acrylic monomer having an organic functional group is preferable. Here, examples of the organic functional group include a carboxyl group, a hydroxy group, an amino group, an epoxy group, and an amide group.

  Examples of acrylic monomers having no organic functional group include methyl (meth) acrylate, ethyl (meth) acrylate, isopropyl (meth) acrylate, butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, and lauryl (meth). Mention may be made of alkyl (meth) acrylates such as acrylate, stearyl (meth) acrylate, cyclohexyl (meth) acrylate, methoxyethyl (meth) acrylate and ethoxyethyl (meth) acrylate. These can be used alone or in combination of two or more.

  The acrylic polymer used in the present invention preferably has 60 to 99% by mass, more preferably 80 to 98% by mass of a repeating unit derived from a (meth) acrylic acid ester having no organic functional group. doing.

  Examples of acrylic monomers having an organic functional group include (meth) acrylic acid, β-carboxyethyl acrylate, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, chloro-2-hydroxy Organic functional group-substituted alkyl (meth) acrylates such as propyl (meth) acrylate and dimethylaminoethyl (meth) acrylate, diethylene glycol mono (meth) acrylate, glycidyl (meth) acrylate, (meth) acrylamide, N-methylol (meth) acrylamide And N-ethylol (meth) acrylamide. These can be used alone or in combination of two or more.

  The acrylic polymer used in the present invention preferably has 1 to 20% by mass, more preferably 2 to 10% by mass, of repeating units derived from the organic functional group-containing acrylic monomer.

  The acrylic polymer used in the present invention is an acrylic monomer having no organic functional group and an acrylic monomer having an organic functional group, and other monomers copolymerizable with these monomers (however, described later) (A), (b), and (c) except those corresponding to the components are excluded.), And the total of these three types of monomers may be 100% by mass. That is, the (A) acrylic polymer may have a repeating unit derived from a monomer other than the above-mentioned acrylic monomer having no organic functional group and an acrylic monomer having an organic functional group. Examples of these include a repeating unit derived from a styrene monomer and a repeating unit derived from a vinyl monomer.

  Specifically, examples of styrenic monomers include alkyls such as styrene, methyl styrene, dimethyl styrene, trimethyl styrene, ethyl styrene, diethyl styrene, triethyl styrene, propyl styrene, butyl styrene, hexyl styrene, heptyl styrene and octyl styrene. Styrene; halogenated styrenes such as fluorostyrene, chlorostyrene, bromostyrene, dibromostyrene, and iodostyrene; and nitrostyrene, acetylstyrene, methoxystyrene, and the like.

  Examples of vinyl monomers include vinyl pyridine, vinyl pyrrolidone, vinyl carbazole, divinyl benzene, vinyl acetate and acrylonitrile; conjugated diene monomers such as butadiene, isoprene and chloroprene; vinyl halides such as vinyl chloride and vinyl bromide; And vinylidene halides such as vinylidene chloride.

  These monomers can be used alone or in combination of two or more. In the acrylic polymer used in the present invention, the repeating unit derived from the other monomer is usually contained in an amount of 0 to 20% by mass, preferably 0 to 10% by mass.

  The acrylic polymer used in the present invention is necessary after a known method, for example, by introducing the above monomer into the reaction solvent and replacing the air in the reaction system with an inert gas such as nitrogen gas. Can be produced by heating and stirring in the presence of a reaction initiator to cause a polymerization reaction.

  The use of the above reaction solvent is optional, and usually an organic solvent is used. For example, aromatic hydrocarbons such as toluene and xylene, aliphatic hydrocarbons such as n-hexane, esters such as ethyl acetate and butyl acetate And alcohols such as n-propyl alcohol and i-propyl alcohol, and ketones such as methyl ethyl ketone, methyl isobutyl ketone and cyclohexanone.

  Moreover, when using a reaction initiator, well-known radical polymerization initiators, such as azobisisobutyronitrile, benzoyl peroxide, di-t-butyl peroxide, cumene hydroperoxide, can be used, for example.

  The reaction temperature of the above polymerization reaction may be about 50 to 90 ° C., and the reaction time is about 2 to 20 hours, preferably 4 to 12 hours. In the reaction as described above, the monomer is charged corresponding to the amount of each repeating unit in the acrylic polymer to be obtained. Moreover, when using a reaction solvent, it is used in the quantity of 50-300 mass parts with respect to 100 mass parts of total amounts of a monomer. Further, the reaction initiator is usually used in an amount of 0.01 to 10 parts by mass.

  By making it react in this way, the acrylic polymer used by this invention is obtained as a solution or dispersion liquid in which the (co) polymer is contained in the reaction solvent in an amount of 25 to 70% by mass. In the present invention, the acrylic polymer and other components may be mixed in a state dissolved or dispersed in the reaction solvent without removing the reaction solvent obtained as described above.

  The acrylic polymer used in the present invention is usually 100,000 to 1,500,000, preferably 300,000 to 800,000 in terms of mass average molecular weight (polystyrene conversion value by gel permeation chromatography (GPC). , The same.) In addition, you may mix | blend other components, such as an inorganic filler, with this acrylic polymer in the range which does not impair the objective of this invention.

[(B) Adhesive modifier]
The adhesive modifier comprising an acrylic / silicone-based graft copolymer having a hydrolyzable silyl group as the component (B) has an effect of imparting appropriate peelability and long-term stability of adhesive strength to the composition of the present invention. Have

  The (B) component hydrolyzable silyl group-containing acrylic / silicone graft copolymer can be obtained by radical copolymerization of the following components (a), (b), (c) and (d). .

(A) 1 to 60% by mass of an organopolysiloxane compound having one radical polymerizable group in one molecule;
(B) 5 to 40% by mass of a radical polymerizable organic silicon compound represented by the following formula (1)
X—R ¹ —SiR ² _3-a (OR ³ ) _a (1)
(In the formula, X is a radically polymerizable group, R ¹ is 1 to 1 carbon atoms in which an oxygen atom may be interposed.
12 divalent hydrocarbon groups or single bonds, R ² and R ³ are each a monovalent hydrocarbon group having 1 to 4 carbon atoms, and a is an integer of 1 to 3. )
(C) 0 to 30% by mass of a polyoxyalkylene compound having one radical polymerizable group in one molecule,
(D) Acrylic monomer (however, excluding those corresponding to the above components (a), (b), (c)) 0 to 94% by mass
(However, the total of the components (a), (b), (c) and (d) is 100% by mass).

（式中、Ｒ⁴は水素原子又はメチル基、Ｒ⁵は酸素原子が介在してもよい炭素原子数１〜１２のアルキレン基等の２価炭化水素基、Ｒ⁶はメチル基又はトリメチルシロキシ基、Ｒ⁷は炭素原子数１〜４のアルキル基等の１価炭化水素基であり、ｂは平均重合度を示す０〜２００の数、ｃは１〜３の整数である。） The organopolysiloxane compound having one radical polymerizable group in one molecule of the component (a) is a component that relaxes the initial adhesiveness of the pressure-sensitive adhesive composition of the present invention and imparts peelability. Although it does not restrict | limit as long as it has one radical polymerizable group in 1 molecule, such as a meth) acryl group, a styryl group, a cinnamic ester group, a vinyl group, an allyl group, The said (b), (c) , Easiness of copolymerization with the component (d), ease of synthesis or availability of the organopolysiloxane compound itself, and the effect of imparting peelability to the pressure-sensitive adhesive composition of the present invention From the viewpoint, a radical polymerizable organopolysiloxane compound represented by the following formula (2) is preferable.

(Wherein R ⁴ is a hydrogen atom or a methyl group, R ⁵ is a divalent hydrocarbon group such as an alkylene group having 1 to 12 carbon atoms in which an oxygen atom may be interposed, and R ⁶ is a methyl group or a trimethylsiloxy group. R ⁷ is a monovalent hydrocarbon group such as an alkyl group having 1 to 4 carbon atoms, b is a number of 0 to 200 indicating the average degree of polymerization, and c is an integer of 1 to 3).

Specific examples of R ⁵ include —CH ₂ —, — (CH ₂ ) ₂ —, — (CH ₂ ) ₃ —, —CH ₂ (CH ₃ ) CHCH ₂ —, — (CH ₂ ) ₆ —, — (CH ₂ ) ₁₂ —, — (CH ₂ ) ₂ —O— (CH ₂ ) ₃ —, — (CH ₂ ) ₂ —O— (CH ₂ ) ₂ —O— (CH ₂ ) ₃ — and the like. .

Specific examples of R ⁷ include —CH ₃ , —CH ₂ CH ₃ , —CH ₂ CH ₂ CH ₃ , —CH ₂ CH ₂ CH ₂ CH _{3 and the} like.

  b is a number from 0 to 200, preferably from 0 to 100. When b exceeds 200, the resulting acrylic / silicone graft copolymer having a hydrolyzable silyl group is insufficiently compatible with the acrylic polymer of component (A), and it is separated from the adhesive composition or peeled off. The phenomenon that adhesiveness cannot be obtained due to excessive strength may occur.

  The (a) radical polymerizable organopolysiloxane compound is usually a (meth) acrylate-substituted chlorosilane compound represented by the following formula (4) and a one-terminal hydroxyl group-containing dimethylpolysiloxane compound represented by the following formula (5). Dehydrochlorination reaction according to the method, or (meth) acrylate-substituted chlorosilane compound of formula (4) and dimethylpolysiloxane compound having —OLi at one end represented by the following formula (6) according to a conventional method Can be obtained. However, the synthesis method is not limited to these.

（式中、Ｒ⁴、Ｒ⁵、Ｒ⁶、Ｒ⁷、ｂ及びｃは上記の通り。）

(In the formula, R ⁴ , R ⁵ , R ⁶ , R ⁷ , b and c are as described above.)

  Specific examples of the radical polymerizable organopolysiloxane compound represented by the formula (2) include compounds represented by the following formulas (7) to (14).

The component (b) radical polymerizable organosilicon compound is a component that imparts long-term stability of adhesive strength to the pressure-sensitive adhesive composition of the present invention, and is represented by the following formula (1).
X—R ¹ —SiR ² _3-a (OR ³ ) _a (1)
(Wherein X is a radically polymerizable group, R ¹ is a divalent hydrocarbon group such as an alkylene group having 1 to 12 carbon atoms in which an oxygen atom may intervene or a single bond, R ² and R ³ are each carbon. A monovalent hydrocarbon group such as an alkyl group having 1 to 4 atoms, and a is an integer of 1 to 3)

Specific examples of X include the substituents shown below.

Specific examples of R ¹ include —CH ₂ —, — (CH ₂ ) ₂ —, — (CH ₂ ) ₃ —, —CH ₂ (CH ₃ ) CHCH ₂ —, — (CH ₂ ) ₆ —, — (CH ₂ ) ₁₂ —, — (CH ₂ ) ₂ —O— (CH ₂ ) ₃ —, — (CH ₂ ) ₂ —O— (CH ₂ ) ₂ —O— (CH ₂ ) ₃ — and the like. .
Specific examples of R ² and R ³ include —CH ₃ , —CH ₂ CH ₃ , —CH ₂ CH ₂ CH ₃ , CH ₂ CH ₂ CH ₂ CH _{3 and the} like.

  Specific examples of the radical polymerizable organosilicon compound represented by the above formula (1) include compounds represented by the following formulas (15) to (28).

  The polyoxyalkylene compound having one radical polymerizable group in one molecule of the component (c) has an affinity for the component (A) in the pressure-sensitive adhesive composition of the present invention, and the adhesive composition Among them, the component (B) is a component having an action of preventing phase separation, and a compound represented by the following formula (3) is preferable.

（式中、Ｒ⁸は水素原子又はメチル基、Ｒ⁹は炭素原子数１〜４のアルキル基等の１価炭化水素基又はアセチル基であり、ｄは平均で２≦ｄ≦３を満足する数、ｅは平均重合度を示す２〜１００の数である。）

Wherein R ⁸ is a hydrogen atom or a methyl group, R ⁹ is a monovalent hydrocarbon group such as an alkyl group having 1 to 4 carbon atoms or an acetyl group, and d satisfies 2 ≦ d ≦ 3 on average. The number e is a number from 2 to 100 indicating the average degree of polymerization.)

Specific examples of R ⁹ include —CH ₃ , —CH ₂ CH ₃ , —CH ₂ CH ₂ CH ₃ , —CH ₂ CH ₂ CH ₂ CH ₃ , —COCH _{3 and the} like.

Equation (3) represents a repeating unit of the polyoxyalkylene moiety in (-C _d H _2d O-) are ethylene oxide units (-C ₂ H ₄ O-) and propylene oxide units (-C ₃ H ₆ O-) In the case of a molar ratio of 1/1, d = 2.5. In the case of a copolymer of an ethylene oxide unit and a propylene oxide unit, it may be a random body or a block body.

  e is 2 to 100, preferably 2 to 50. When e exceeds 100, the solubility with the (a) organopolysiloxane compound, which is a copolymerizable component, deteriorates and a homogeneous copolymer cannot be obtained.

  Specific examples of the polyoxyalkylene compound having a radical polymerizable group represented by the formula (3) include compounds represented by the following formulas (29) to (37).

  These polyoxyalkylene compounds having radically polymerizable groups are available on the market and are sold by Kyoeisha Chemical Co., Ltd. (light ester series, light acrylate series), Shin-Nakamura Chemical Industry (NK ester series), etc. Has been.

  The acrylic monomer of component (d) is a unit that constitutes the backbone polymer of the acrylic / silicone graft copolymer, and is indispensable in combination with other components (a), (b), and (c). Although it is not a component, it is preferable to have it for the effect of homogeneously copolymerizing the three components (a), (b), and (c) and the affinity with the acrylic polymer of component (A). It is. The (d) acrylic monomer is one excluding those corresponding to the above components (a), (b), and (c).

  As the acrylic monomer for the component (d), the same acrylic monomer as used for the component (A) can be used. That is, as an acrylic monomer having no organic functional group, methyl (meth) acrylate, ethyl (meth) acrylate, isopropyl (meth) acrylate, butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, lauryl (meth) acrylate , Stearyl (meth) acrylate, cyclohexyl (meth) acrylate, methoxyethyl (meth) acrylate and alkyl (meth) acrylate such as ethoxyethyl (meth) acrylate can be used. As an acrylic monomer having an organic functional group, (meth ) Acrylic acid, β-carboxyethyl acrylate, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, chloro-2-hydroxypropyl (meth) acrylate, dimethyl Organic functional group-substituted alkyl (meth) acrylates such as ruaminoethyl (meth) acrylate, diethylene glycol mono (meth) acrylate, glycidyl (meth) acrylate, (meth) acrylamide, N-methylol (meth) acrylamide and N-ethylol (meth) acrylamide Etc. can be used. These may be used alone or in combination of two or more, and any monomer may be used, but the resulting (B) component acrylic / silicone-based graft copolymer and (A) component acrylic polymer As a component that can be expected to react with glycidyl (meth) acrylate having an epoxy functional group, it is preferable.

  (B) The ratio of the monomer component which comprises the acrylic / silicone-type graft copolymer of a component is (a) 1-60 mass%, (b) 5-40 mass%, (c) 0-30 mass%, ( d) 0 to 94% by mass, preferably (a) 5 to 50% by mass, (b) 10 to 30% by mass, (c) 5 to 20% by mass, (d) 5 to 80% by mass, , (A), (b), (c) and (d) are 100% by mass in total.

  When the component (a) exceeds 60% by mass, the compatibility with the acrylic polymer of the component (A) is insufficient, causing a phenomenon in which the adhesive property cannot be obtained due to separation from the adhesive composition or too strong peelability. . In addition, when the component (b) is less than 5% by mass, the long-term stability of the adhesive strength is insufficient, and when it exceeds 40% by mass, the storage stability of the adhesive composition is deteriorated or the releasability necessary for the initial stage appears I do not. Moreover, when (c) component exceeds 30 mass%, affinity with the acrylic polymer of (A) component will become strong too much, and initial stage peelability and long-term stability of adhesive strength will be insufficient.

  The (B) component acrylic / silicone graft copolymer can be produced by a known method similar to the (A) component acrylic polymer. That is, this is a method in which the components (a), (b), (c) and (d) described above are subjected to a polymerization reaction in a reaction solvent by heating and stirring in the presence of a reaction initiator. The reaction solvent, reaction initiator, reaction temperature, and reaction time at this time may be the same as in the case of component (A). Although the reaction solvent may be removed from the copolymer solution obtained by the reaction to take out the copolymer, it may be used as it is without removing the reaction solvent. The upper limit of the molecular weight of the copolymer is not particularly limited, but those having a weight average molecular weight of usually up to 500,000, preferably up to 200,000 are used. If the molecular weight exceeds 500,000, the compatibility with the acrylic polymer of component (A) may be insufficient.

In the pressure-sensitive adhesive composition for optical use of the present invention, the adhesive modifier of the component (B) is usually 0.01 to 10 parts by mass with respect to 100 parts by mass of the acrylic polymer of the component (A). It is preferably contained in an amount of 0.05 to 5 parts by mass. When the amount of the component (B) is too large, the initial adhesive strength is lowered, and the polarizing plate or the laminated plate of the polarizing plate and the retardation plate is likely to be swollen or peeled off in the environment where the liquid crystal element is used. Also, if the amount of the component (B) is too small, the adhesive strength becomes too high when heated in the manufacturing process and the appropriate peelability is lost. When the polarizing plate or the laminated plate of the polarizing plate and the retardation plate is peeled off from the substrate, the liquid crystal cell is easily damaged, and the adhesive remains on the substrate surface easily.
The acrylic polymer (A) and the adhesive modifier (B) are preferably mixed immediately before use of the composition.

[Other ingredients]
The optical pressure-sensitive adhesive composition of the present invention contains the above-mentioned (A) acrylic polymer and (B) specific adhesion modifier as essential components, but further contains other components as necessary. You may go out.
Examples of other components that can be blended in the optical pressure-sensitive adhesive composition of the present invention include tackifiers, plasticizers, crosslinking agents, and dyes. These may be known ones, and these optional components may be used singly or in combination of two or more.

  In particular, it is preferable that a crosslinking agent is blended in the optical pressure-sensitive adhesive composition of the present invention. Examples of the crosslinking agent used in the present invention include isocyanate compounds, epoxy compounds, amine compounds, metal chelate compounds, and aziridine compounds.

  Examples of isocyanate compounds used as crosslinking agents include tolylene diisocyanate, hydrogenated tolylene diisocyanate, tolylene diisocyanate adduct of trimethylol propane, xylylene diisocyanate adduct of trimethylol propane, triphenylenemethane triisocyanate, isophorone diisocyanate, and These ketoxime block products or phenol block products can be mentioned.

  Examples of the epoxy compound include bisphenol A, epichlorohydrin type epoxy resin, ethylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, glycerin diglycidyl ether, glycerin triglycidyl ether, and 1,6-hexanediol diglycidyl. Ether, trimethylolpropane triglycidyl ether, diglycidylaniline, diglycidylamine, N, N, N ′, N′-tetraglycidyl-m-xylenediamine and 1,3-bis (N, N′-diglycidylaminomethyl) ) Cyclohexane and the like.

  Furthermore, examples of the amine compound include hexamethylenediamine, polyethyleneimine, hexamethylenetetramine, diethylenetriamine, triethylenetetramine, isophoronediamine, amino resin, and melamine resin.

  Still further, examples of metal chelate compounds include compounds in which acetylacetone is coordinated to a polyvalent metal such as aluminum, iron, copper, zinc, tin, titanium, nickel, antimony, magnesium, vanadium, chromium and zirconium, Examples include compounds in which ethyl acetoacetate is coordinated to a metal.

  Further, examples of the aziridine compounds include N, N′-diphenylmethane-4,4′-bis (1-aziridinecarboxamide), N, N′-toluene-2,4-bis (1-aziridinecarboxamide), tri Ethylenemelamine, bisisophthaloyl-1- (2-methylaziridine), tri-1-aziridinylphosphine oxide, N, N′-hexamethylene-1,6-bis (1-aziridinecarboxamide), trimethylolpropane -Tri-β-aziridinylpropionate, tetramethylolmethane-tri-β-aziridinylpropionate, and the like can be mentioned.

These crosslinking agents can be used singly or in combination of two or more.
The cross-linking agent is usually used in an amount of 0.01 to 10 parts by mass, preferably 0.05 to 5 parts by mass with respect to 100 parts by mass of the component (A) in the composition of the present invention. In addition, since these crosslinking agents often have reactivity with the components (A) and (B) of the present invention, they are preferably packaged separately and mixed before use.

  The present invention will be described in more detail below with reference to synthesis examples, examples and comparative examples of the present invention. However, the present invention should not be construed as being limited to these examples.

で表されるラジカル重合性基含有オルガノポリシロキサン化合物３０質量部、下記式（１６）；

で表されるラジカル重合性有機珪素化合物（信越化学工業（株）製、ＫＢＭ−５０３）１５質量部、下記式（３０）；

で表されるラジカル重合性基含有ポリオキシアルキレン化合物（共栄社化学（株）製、ライトエステル１３０ＭＡ）１０質量部、ｎ−ブチルアクリレート３０質量部、エチルアクリレート１０質量部、グリシジルメタクリレート５質量部、メチルエチルケトン７５質量部、酢酸エチル７５質量部、及びアゾビスイソブチルニトリル２質量部を仕込み、窒素気流中攪拌しながら８０〜８５℃で５時間重合反応を行ない、固形分４０質量％の無色透明な粘性液体を得た。なお、ゲルパーミエーションクロマトグラフィー（ＧＰＣ）によるポリスチレン換算の重量平均分子量は６２，０００であった。 [Synthesis Example 1]
In a glass reaction vessel, the following formula (9):

30 parts by mass of a radical polymerizable group-containing organopolysiloxane compound represented by the following formula (16):

15 parts by mass of a radical polymerizable organosilicon compound (KBE-503, manufactured by Shin-Etsu Chemical Co., Ltd.) represented by the following formula (30);

10 parts by mass of a radical polymerizable group-containing polyoxyalkylene compound represented by the formula (Kyoeisha Chemical Co., Ltd., light ester 130MA), 30 parts by mass of n-butyl acrylate, 10 parts by mass of ethyl acrylate, 5 parts by mass of glycidyl methacrylate, methyl ethyl ketone 75 parts by mass, 75 parts by mass of ethyl acetate, and 2 parts by mass of azobisisobutylnitrile were added, and the polymerization reaction was carried out at 80 to 85 ° C. for 5 hours while stirring in a nitrogen stream. A colorless transparent viscous liquid having a solid content of 40% by mass Got. In addition, the weight average molecular weight of polystyrene conversion by gel permeation chromatography (GPC) was 62,000.

また、合成例５、６で用いる（ｃ）成分の他の成分は、下記式（３８）で表されるものである。

共栄社化学（株）製、ライトアクリレートＤＰＭ−Ａ [Synthesis Examples 2 to 8]
In each synthesis example, the same operation was performed except that each radical polymerizable component and the charged amount (part by mass) used in Synthesis Example 1 were changed as shown in Table 1, and the copolymer having the weight average molecular weight shown in Table 1 was obtained. Was obtained.
In addition, the other component of the component (a) used in Synthesis Example 4 is represented by the following formula (7).

The other component (c) used in Synthesis Examples 5 and 6 is represented by the following formula (38).

Kyoeisha Chemical Co., Ltd., light acrylate DPM-A

[Example 1]
43 parts by mass of n-butyl acrylate, 20 parts by mass of ethyl acrylate, 25 parts by mass of 2-ethylhexyl acrylate, 3 parts by mass of styrene, 7 parts by mass of acrylic acid, 2 parts by mass of 2-hydroxyethyl acrylate, 100 parts by mass of ethyl acetate and After 0.2 parts by mass of azobisisobutyronitrile was put into a reactor and the inside of the reactor was replaced with nitrogen gas, the mixture was reacted at 63 ° C. for 2 hours in a nitrogen atmosphere with stirring. Furthermore, 10 parts by mass of a solution prepared by dissolving 0.05 parts by mass of azobisisobutyronitrile in 10 parts by mass of ethyl acetate, which was separately prepared, was added dropwise to the reactor at 63 ° C. over 2 hours. Next, the temperature was raised to 72 ° C., and 10 parts by mass of an ethyl acetate solution of azobisisobutyronitrile prepared in the same manner as above was dropped over 4 hours to obtain 220 parts by mass of an ethyl acetate solution of an acrylic polymer. . The concentration of the acrylic polymer in the ethyl acetate solution is 45% by mass.
1.5 parts by mass of the acrylic / silicone graft copolymer solution synthesized in Synthesis Example 1 (corresponding to 0.6 parts by mass of the copolymer) in 220 parts by mass of the reaction liquid (corresponding to 100 parts by mass of the acrylic polymer). ) And 2 parts by mass of a polyisocyanate compound (trade name: Coronate L, manufactured by Nippon Polyurethane Co., Ltd.) as a cross-linking agent and stirred well to obtain an adhesive composition of the present invention.
The adhesive composition obtained as described above was applied to a polyester release film and then dried to form a coating having a thickness of 25 μm after drying. Next, the coating film of the adhesive composition on the release film was transferred onto one surface of a 0.20 mm thick polarizing plate and aged for 7 days under conditions of a temperature of 23 ° C. and a humidity of 65%. Thereafter, the film side of the adhesive composition of the polarizing plate was bonded to the surface of the glass substrate to prepare a sample. This sample was bonded by holding for 20 minutes at a temperature of 50 ° C. and a pressure of 5 kg / cm ² .

<Peelability>
(Initial bond strength)
Regarding the adhesive force between the polarizing plate and the glass substrate thus bonded, the initial adhesive strength (adhesive strength after being left at 23 ° C. for 1 hour) was measured according to JIS-Z-0237 and JIS-Z-0238.

(Adhesive strength after heat aging)
Further, the sample prepared in the same manner as described above was allowed to stand at 80 ° C. for 10 hours, then allowed to cool to 23 ° C., left at this temperature for 1 hour, and then the adhesive strength was measured in the same manner as described above.

(Remaining glue)
As described above, in the measurement of the adhesive strength at the initial stage and after heat aging, when the polarizing plate was peeled off from the glass substrate, whether or not the adhesive remained on the glass substrate surface (that is, the residue) was visually observed. And evaluated.

<Mountability>
A sample prepared in the same manner as above was cut into a size of 20 cm × 30 cm in length and width, adhered under the above conditions, and allowed to stand at 100 ° C. under dry conditions for 800 hours. After leaving at 90% RH for 800 hours, the presence or absence of foaming in the adhesive composition coating and the occurrence of peeling between the polarizing plate and the glass substrate were visually observed and evaluated.
These results are shown in Table 2. In this example, the liquid crystal element in which the polarizing plate was bonded to the glass substrate surface showed good characteristics.

[Example 2]
An adhesive composition was obtained in the same manner except that the acrylic / silicone-based graft copolymer solution synthesized in Synthesis Example 1 used in Example 1 was replaced with 10 parts by mass (corresponding to 4 parts by mass of the copolymer). It was. The properties of the adhesive composition were evaluated in the same manner as in Example 1. The results are shown in Table 2. In this example, the liquid crystal element in which the polarizing plate was bonded to the glass substrate surface showed good characteristics.

[Examples 3 to 8]
In Example 1, instead of the acrylic / silicone graft copolymer solution synthesized in Synthesis Example 1, Example 1 except that the acrylic / silicone graft copolymer solution synthesized in Synthesis Examples 2-7 was used. Similarly, an adhesive composition was obtained. The properties of the adhesive composition were evaluated in the same manner as in Example 1. The results are shown in Table 2. In this example, the liquid crystal element in which the polarizing plate was bonded to the glass substrate surface showed good characteristics.

[Comparative Example 1]
In Example 1, the same procedure as in Example 1 was used except that the acrylic / silicone graft copolymer solution synthesized in Synthesis Example 8 was used instead of the acrylic / silicone graft copolymer solution synthesized in Synthesis Example 1. Thus, an adhesive composition was obtained. The properties of the adhesive composition were evaluated in the same manner as in Example 1. The results are shown in Table 2.

  Although the present invention has been described with the embodiment, the present invention is not limited to the embodiment shown here, and those skilled in the art will conceive other embodiments, additions, modifications, deletions, and the like. As long as the effects of the present invention are exhibited in any aspect, the present invention is included in the scope of the present invention.

Claims (5)

(A) 100 parts by mass of an acrylic polymer,
(B) Adhesive modification comprising a radical copolymer of the following components (a), (b), (c) and (d), comprising an acrylic / silicone graft copolymer having a hydrolyzable silyl group An optical pressure-sensitive adhesive composition containing 0.01 to 10 parts by mass of an agent.
(A) 1 to 60% by mass of an organopolysiloxane compound having one radical polymerizable group in one molecule;
(B) 5 to 40% by mass of a radical polymerizable organic silicon compound represented by the following formula (1)
X—R ¹ —SiR ² _3-a (OR ³ ) _a (1)
(In the formula, X is a radically polymerizable group, R ¹ is a divalent hydrocarbon group having 1 to 12 carbon atoms or a single bond in which an oxygen atom may be interposed, and R ² and R ³ each have 1 to 1 carbon atoms. 4 is a monovalent hydrocarbon group, and a is an integer of 1 to 3.)
(C) 0 to 30% by mass of a polyoxyalkylene compound having one radical polymerizable group in one molecule,
(D) Acrylic monomer (however, excluding those corresponding to the above components (a), (b), (c)) 0 to 94% by mass
(However, the total of the components (a), (b), (c) and (d) is 100% by mass).   The acrylic polymer as the component (A) is 60 to 99% by mass of an acrylic monomer having no organic functional group, 1 to 20% by mass of an acrylic monomer having an organic functional group, and other copolymerizable with these monomers. A copolymer in which 0 to 20% by mass of the monomers (excluding those corresponding to the above components (a), (b) and (c)) is 100% by mass in total of these three types of monomers. The pressure-sensitive adhesive composition for optical use according to claim 1. The optical pressure-sensitive adhesive composition according to claim 1 or 2, wherein the component (a) is an organopolysiloxane compound represented by the following general formula (2).

(Wherein R ⁴ is a hydrogen atom or a methyl group, R ⁵ is a C 1-12 divalent hydrocarbon group in which an oxygen atom may be interposed, R ⁶ is a methyl group or a trimethylsiloxy group, R ⁷ is (It is a monovalent hydrocarbon group having 1 to 4 carbon atoms, b is a number of 0 to 200 indicating the average degree of polymerization, and c is an integer of 1 to 3). The optical feeling according to any one of claims 1 to 3, wherein the component (c) is a polyoxyalkylene compound represented by the following general formula (3) and is contained in a proportion of 5 to 20% by mass. Pressure adhesive composition.

(Wherein R ⁸ is a hydrogen atom or a methyl group, R ⁹ is a monovalent hydrocarbon group or an acetyl group having 1 to 4 carbon atoms, d is a number satisfying 2 ≦ d ≦ 3 on average, and e is It is a number from 2 to 100 indicating the average degree of polymerization.)   The optical pressure-sensitive adhesive composition according to any one of claims 1 to 4, wherein the component (d) contains an acrylic monomer having an epoxy functional group and is contained at a ratio of 5 to 80% by mass.