JP2008031293A - Adhesive composition, and pressure-sensitive adhesive sheet and adhesive optical member using it - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an adhesive composition giving a pressure-sensitive adhesive sheet and an adhesive optical member good in peeling antistatic property, adhesiveness, adhesion durability, etc., and the pressure-sensitive adhesive sheet and the adhesive optical member obtainable using this adhesive composition. <P>SOLUTION: This adhesive composition contains a (meth)acrylic acid ester polymer (A) and an ion conductive agent (B) comprising a combination of an electrolyte salt (b-1) having an alkali metal cation and a polyvalent carboxylic acid ester (b-2), this pressure-sensitive adhesive sheet has at least on one side of its substrate an adhesive layer formed using the adhesive composition, and this adhesive optical member has at least on one side of its sheet-like optical member an adhesive layer formed using the adhesive composition. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an adhesive composition, an adhesive sheet using the same, and an adhesive optical member. More specifically, the present invention relates to an adhesive composition excellent in antistatic property, an antistatic adhesive sheet used for each optical member in a liquid crystal display or the like, and a polarizing plate, using the adhesive composition. The present invention relates to an adhesive optical member.

Optical members such as a polarizing plate, a retardation plate, an optical compensation film, a reflection sheet, and a brightness enhancement film used for a liquid crystal display are bonded to a liquid crystal cell or the like via an adhesive layer.
In addition, these optical members to be bonded to the liquid crystal cell have a surface protective film bonded via an adhesive layer agent for the purpose of preventing scratches and dirt generated during processing and transportation. And this surface protection film peels and is removed in the stage which became unnecessary.
By the way, in a liquid crystal cell, generally, two transparent electrode substrates on which an alignment layer is formed are arranged so that the alignment layer is inside and a predetermined gap is provided by a spacer, the periphery is sealed, and a liquid crystal is placed in the gap. In addition to sandwiching the material, a polarizing plate is disposed on the outer surface of each of the two transparent electrode substrates via an adhesive layer.
FIG. 1 is a perspective view showing a configuration of an example of the polarizing plate. As shown in this figure, the polarizing plate 10 is generally a base material having a three-layer structure in which triacetyl cellulose (TAC) films I2 and II2 ′ are bonded to both surfaces of a polyvinyl alcohol polarizer 1. And the adhesive layer 3 for adhering to optical components, such as a liquid crystal cell, is formed in the single side | surface, Furthermore, the peeling sheet 4 is affixed on this adhesive layer 3 Yes. Moreover, the surface protective film 5 is normally provided in the surface on the opposite side to this adhesive layer 3 of this polarizing plate.
When sticking such a polarizing plate to the liquid crystal cell, first, the release sheet 4 is peeled off, attached to the liquid crystal cell via the exposed adhesive layer 3, and then the surface protective film 5 is peeled off.
When the release sheet 4 or the surface protective film 5 is peeled off, these sheets, film, and polarizing plate are made of a plastic material, so that the electrical insulation is high and static electricity is generated. If a voltage is applied to the liquid crystal cell while the static electricity generated at this time remains, the alignment of the liquid crystal molecules is disturbed. In addition, the presence of static electricity causes problems such as sucking dust and dirt. Therefore, development of a countermeasure for preventing electrostatic charging for a polarizing plate, a release sheet, or a surface protective film is eagerly desired.
As an attempt to suppress electrostatic charging, for example, by adding a low-molecular surfactant to the adhesive, moisture in the air is adsorbed to the surfactant that has migrated to the surface of the adhesive layer, and an antistatic function is exhibited. (For example, refer to Patent Document 1). However, in this case, there is a drawback that the antistatic performance and the adhesive force are greatly affected by humidity.
In the pressure-sensitive adhesive composition comprising a (meth) acrylic polymer mainly comprising a (meth) acrylic monomer having an alkyl group having 6 to 14 carbon atoms, and a polyether polyol compound and an alkali metal salt, A pressure-sensitive adhesive composition comprising a meth) acrylic polymer having an acid value of 1.0 or less and containing less than 0.1 part by weight of the alkali metal salt with respect to 100 parts by weight of the (meth) acrylic polymer is disclosed. (For example, refer to Patent Document 2).
However, this pressure-sensitive adhesive composition uses a combination of a polyether polyol compound and an alkali metal salt as a conductive agent, and can sufficiently satisfy all of anti-peeling property, adhesion and durability. It is not a thing.
JP-A-61-138901 JP 2005-325255 A

  Under such circumstances, the present invention uses a pressure-sensitive adhesive composition that provides a pressure-sensitive adhesive sheet and a pressure-sensitive optical member having good antistatic properties, adhesion and adhesion durability, and the pressure-sensitive adhesive composition. It was made for the purpose of providing the above-mentioned pressure-sensitive adhesive sheet and pressure-sensitive optical member obtained.

（式中、Ｒ³は一価の有機基、Ｒ⁴〜Ｒ⁶は、それぞれ独立にアルキレン基、Ｒ⁷は水素原子又は一価の有機基、ａは０〜１００の整数、ｂは１〜１００の整数、ｃ及びｄは、それぞれ独立に０〜１００の整数を示すが、ｃ及びｄが同時に０であることはない。）
で表される化合物である上記(２)〜(４)項のいずれかに記載の粘着剤組成物、
（６）基材の少なくとも片面に、上記(１)〜(５)項のいずれかに記載の粘着剤組成物を用いて形成された粘着剤層を有することを特徴とする粘着シート、
（７）シート状光学部材の少なくとも片面に、上記(１)〜(５)項のいずれかに記載の粘着剤組成物を用いて形成された粘着剤層を有することを特徴とする粘着性光学部材、及び
（８）シート状光学部材が偏光板である上記(７)項に記載の粘着性光学部材、
を提供するものである。 As a result of intensive studies to achieve the above object, the present inventors have found that an adhesive component comprising a (meth) acrylic acid ester polymer, and an ion comprising a specific electrolyte salt and a complete ester of a polyvalent carboxylic acid. It has been found that the object can be achieved by a pressure-sensitive adhesive composition containing a conductive agent and, if necessary, a conductive polyorganosiloxane, and the present invention has been completed based on this finding.
That is, the present invention
(1) (A) (Meth) acrylic acid ester polymer, and (B) (b-1) an ion comprising a combination of an electrolyte salt having an alkali metal cation and (b-2) an ester of a polyvalent carboxylic acid A pressure-sensitive adhesive composition comprising a conductive agent;
(2) The pressure-sensitive adhesive composition according to item (1), further comprising (C) a conductive polyorganosiloxane,
(3) The pressure-sensitive adhesive according to (1) or (2) above, containing 0.05 to 1 part by mass and (C) 0.05 to 1 part by mass with respect to 100 parts by mass of component (A) Composition,
(4) The ester of the polyvalent carboxylic acid as the component (b-2) is represented by the general formula (I)
^{R 1 - [COO- (AO)} n -R 2] k ··· (I)
(Wherein R ¹ is an optionally substituted divalent to tetravalent hydrocarbon group having 2 to 15 carbon atoms, R ² is a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, or 2 to 2 carbon atoms. 6 is an acyl group, A is an alkylene group having 2 to 4 carbon atoms, k is an integer of 2 to 4, and n is an integer of 2 to 30.)
The pressure-sensitive adhesive composition according to any one of the above (1) to (3), which is a complete ester represented by:
(5) The conductive polyorganosiloxane of component (C) has the general formula (II)

Wherein R ³ is a monovalent organic group, R ^{4 to} R ⁶ are each independently an alkylene group, R ⁷ is a hydrogen atom or a monovalent organic group, a is an integer from 0 to 100, and b is 1 to (The integer of 100, c and d each independently represents an integer of 0 to 100, but c and d are not 0 at the same time.)
The pressure-sensitive adhesive composition according to any one of the above items (2) to (4), which is a compound represented by:
(6) A pressure-sensitive adhesive sheet comprising a pressure-sensitive adhesive layer formed by using the pressure-sensitive adhesive composition according to any one of (1) to (5) above on at least one surface of a substrate,
(7) Adhesive optics comprising an adhesive layer formed by using the adhesive composition according to any one of (1) to (5) above on at least one surface of a sheet-like optical member. And (8) the adhesive optical member according to item (7), wherein the sheet-like optical member is a polarizing plate,
Is to provide.

  According to the present invention, by containing an ionic conductive agent comprising a specific electrolyte salt and an ester of a polyvalent carboxylic acid and, if necessary, a conductive polyorganosiloxane, it is possible to prevent peeling antistatic properties, adhesion and adhesion durability. It is possible to provide a pressure-sensitive adhesive composition that provides a pressure-sensitive adhesive sheet or a pressure-sensitive optical member. Moreover, adhesive optical members, such as the said adhesive sheet and polarizing plate obtained using this adhesive composition, have the effect that it is hard to generate | occur | produce peeling electrification and is excellent in adhesiveness and durability.

The pressure-sensitive adhesive composition of the present invention comprises (A) (meth) acrylic acid ester polymer, (B) (b-1) an electrolyte salt having an alkali metal cation, and (b-2) an ester of a polyvalent carboxylic acid. It contains an ionic conductive agent consisting of a combination of
In the pressure-sensitive adhesive composition of the present invention, the (meth) acrylic acid ester polymer of the component (A) is not particularly limited, and among the (meth) acrylic acid ester polymers conventionally used as a resin component of the pressure-sensitive adhesive. Any one can be appropriately selected and used. As such a (meth) acrylic acid ester polymer, for example, a (meth) acrylic acid ester in which the alkyl group of the ester moiety has 1 to 20 carbon atoms, a monomer having a functional group having active hydrogen, and a desired Preferred examples include copolymers with other monomers used. In addition, (meth) acrylic acid ester means methacrylic acid ester and / or acrylic acid ester.
Here, examples of the (meth) acrylic acid ester having 1 to 20 carbon atoms in the alkyl group of the ester portion include methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, and butyl (meth) acrylate. , Pentyl (meth) acrylate, hexyl (meth) acrylate, cyclohexyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, isooctyl (meth) acrylate, decyl (meth) acrylate, dodecyl (meth) acrylate, myristyl (meth) acrylate , Palmityl (meth) acrylate, stearyl (meth) acrylate, and the like. These may be used alone or in combination of two or more.
On the other hand, examples of the monomer having a functional group having active hydrogen include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, 2-hydroxybutyl ( Hydroxyalkyl (meth) acrylate such as (meth) acrylate, 3-hydroxybutyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, monomethylaminoethyl (meth) acrylate, monoethylaminoethyl (meth) acrylate, monomethylaminopropyl Monoalkylaminoalkyl (meth) acrylates such as (meth) acrylate and monoethylaminopropyl (meth) acrylate; ethylenically unsaturated carboxylic acids such as acrylic acid, methacrylic acid, crotonic acid, maleic acid, itaconic acid, citraconic acid, etc. But It is below. These monomers may be used independently and may be used in combination of 2 or more type.

Examples of other monomers used as desired include vinyl esters such as vinyl acetate and vinyl propionate; olefins such as ethylene, propylene and isobutylene; halogenated olefins such as vinyl chloride and vinylidene chloride; styrene Styrene monomers such as α-methylstyrene; diene monomers such as butadiene, isoprene and chloroprene; nitrile monomers such as acrylonitrile and methacrylonitrile; acrylamide, N-methylacrylamide, N, N- Examples include acrylamides such as dimethylacrylamide. These may be used alone or in combination of two or more.
The (meth) acrylic acid ester copolymer used as the resin component is not particularly limited as to the form of copolymerization, and may be any of random, block, and graft copolymers. In addition, the molecular weight is preferably 500,000 or more, more preferably 500,000 to 2,500,000 in terms of weight average molecular weight. If the weight average molecular weight is less than 500,000, the adhesion to the adherend and the durable adhesion may be insufficient. In view of adhesiveness and durable adhesiveness, the weight average molecular weight is preferably 700,000 to 1,800,000.
In addition, the said weight average molecular weight is the value of polystyrene conversion measured by the gel permeation chromatography (GPC) method.
Further, in this (meth) acrylic acid ester copolymer, the content of the monomer unit having a functional group having active hydrogen is preferably in the range of 0.01 to 10% by mass. If the content is less than 0.01% by mass, the number of crosslinking points is too small and crosslinking may be insufficient, which may cause cohesive failure of the pressure-sensitive adhesive layer. If the content exceeds 10% by mass, it is suitable for application to a liquid crystal cell or the like. May decrease. The more preferable content of the monomer unit having a functional group having active hydrogen is 0.05 to 6.0% by mass, and the range of 0.2 to 5.0% by mass is particularly preferable.

In the present invention, as the component (A), one type of (meth) acrylic acid ester copolymer may be used, or two or more types may be used in combination.
In the pressure-sensitive adhesive composition of the present invention, an ionic conductive agent is used as the component (B). This ionic conductive agent comprises a combination of an electrolyte salt having an alkali metal cation as the component (b-1) and an ester of a polyvalent carboxylic acid as the component (b-2). As the alkali metal cation in the electrolyte salt which is a component, Li ⁺ , Na ⁺ and K ⁺ can be mentioned, and among these, Li ⁺ is particularly preferable from the viewpoint of performance.
The anion in the electrolyte salt is not particularly limited. For example, F ⁻ , Cl ⁻ , Br ⁻ , I ⁻ , BF ₄ ⁻ , PF ₆ ⁻ , SCN ⁻ , ClO ₄ ⁻ , CF ₃ SO ₃ ⁻ , ( Preferred examples include CF ₃ SO ₂ ) ₂ N ⁻ , (CF ₃ SO ₂ ) ₃ C ⁻ , RSO ₃ ⁻ (R: aryl group), and the like. Among these, ClO ₄ ⁻ is particularly preferable from the viewpoint of performance.
Specific examples of the electrolyte salt used as the component (b-1) include LiBr, LiI, Li
BF ₄ , LiPF ₆ , LiSCN, LiClO ₄ , LiCF ₃ SO ₃ , Li (CF ₃ SO ₂ ) ₂ N, Li (CF ₃ SO ₂ ) ₃ C, further lithium octylbenzenesulfonate, lithium dodecylbenzenesulfonate, Examples thereof include lithium dibutylnaphthalene sulfonate and the like, as well as compounds in which Li (lithium) in these salts is replaced with K or Na. Among these, Li salts are preferable, and LiClO ₄ (lithium perchlorate) is particularly preferable. Is preferred.
In the present invention, the electrolyte salt of the component (b-1) may be used alone or in combination of two or more.

On the other hand, examples of the ester of the polyvalent carboxylic acid as the component (b-2) include, for example, the general formula (I)
^{R 1 - [COO- (AO)} n -R 2] k ··· (I)
The complete ester represented by these can be mentioned.
In the general formula (I), R ¹ represents a divalent to tetravalent hydrocarbon group having carbon atoms of 2 to 15 which may have a substituent. As this hydrocarbon group, the C2-C15 bivalent aliphatic hydrocarbon group and C5-C15 bivalent alicyclic hydrocarbon which may have a substituent may be included. And a divalent to tetravalent aromatic hydrocarbon group having 6 to 15 carbon atoms. Examples of the substituent include a hydroxyl group.
Specific examples of R ¹ include aliphatic polycarboxylic acids such as adipic acid, sebacic acid, azelaic acid, malic acid, citric acid, aconitic acid, butanetricarboxylic acid, butanetetracarboxylic acid, 1,2-, 1, Arocyclic polycarboxylic acids such as 3-, 1,4-cyclohexanedicarboxylic acid, aromatic polycarboxylic acids such as phthalic acid, isophthalic acid, terephthalic acid, 2,6-naphthalenedicarboxylic acid, trimellitic acid, pyromellitic acid Examples thereof include residues obtained by removing a carboxyl group from a polyvalent carboxylic acid such as
R ² represents a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, or an acyl group having 2 to 6 carbon atoms. The alkyl group having 1 to 6 carbon atoms may be linear or branched, and may have a substituent such as a hydroxyl group. For example, a methyl group, an ethyl group, an n-propyl group, an isopropyl group, various butyl groups, various pentyl groups, and various hexyl groups can be exemplified. The acyl group having 2 to 6 carbon atoms may have a substituent such as a hydroxyl group, and examples thereof include an acetyl group, a propionyl group, and a butyryl group.
A represents an alkylene group having 2 to 4 carbon atoms, and the alkylene group may be linear or branched. Specific examples include an ethylene group, a trimethylene group, a tetramethylene group, a propane-1,2-diyl group, and a branched butanediyl group. Among these, an ethylene group and a propane-1,2-diyl group ( Propylene group) is preferred.
n shows the integer of 2-30. In addition, the oxyalkylene group AO may be a mixture of different oxyalkylene groups, or may be a mixture of different addition moles as long as the average addition mole number is in the range of 2-30.

This oxyalkylene moiety has hydrophilicity, and thus the complete ester of the polyvalent carboxylic acid represented by the general formula (I) itself has antistatic properties. In addition, the hydrophilic portion forms a complex with the electrolyte salt as the component (b-1), and exhibits ionic conductivity when a voltage is applied. Therefore, peeling charging is effectively prevented by combining the component (b-1) and the component (b-2).
The complete ester of the polyvalent carboxylic acid represented by the general formula (I) is, for example, the polyvalent carboxylic acid exemplified above and HO— (AO) _n —H (A and n are the same as above). Or HO— (AO) _n —R ^{2 ′} (R ^{2 ′} represents an alkyl group having 1 to 6 carbon atoms, and A and n are the same as described above). It can be produced by reacting polyoxyalkylene glycol monoalkyl ether.
The component (b-2) may be a partial ester of a polyvalent carboxylic acid, but the partial ester has a free carboxyl group in the molecule, and this carboxyl group is a component of the component (b-1). Complete esters are preferred because they have a large interaction with the electrolyte salt and cause ionic conduction.
In the ionic conductive agent of the component (B), the content ratio of the component (b-1) and the component (b-2) is usually 0.01: 99.99 to 30:70 in terms of mass ratio, preferably It is 0.1: 99.9-50: 50.
The content of the ionic conductive agent of the component (B) in the pressure-sensitive adhesive composition of the present invention is such that the (meth) acrylic acid ester of the component (A) is from the viewpoints of antistatic resistance to peeling, adhesiveness and adhesion durability. The amount is usually about 0.05 to 1 part by mass, preferably 0.1 to 0.7 part by mass, and more preferably 0.12 to 0.5 part by mass with respect to 100 parts by mass of the polymer.
In the pressure-sensitive adhesive composition of the present invention, (C) conductive polyorganosiloxane can be included as desired.
Although there is no restriction | limiting in particular as this electroconductive polyorganosiloxane, For example, general formula (II)

で表される化合物を好ましく挙げることができる。
前記一般式（II）において、Ｒ³は一価の有機基を示す。この一価の有機基としては、例えばメチル基、エチル基、プロピル基等の炭素数１〜４のアルキル基、フェニル基、トリル基等の炭素数６〜８のアリール基、ベンジル基、フェネチル基等の炭素数７〜９のアラルキル基などが挙げられ、水酸基等の置換基を有してもよい。
Ｒ⁴〜Ｒ⁶は、それぞれ独立にアルキレン基を示す。このアルキレン基としては、炭素数１〜８の直鎖状又は分岐状のアルキレン基、例えばメチレン基、エチレン基、プロパン−１,２−ジイル基（プロピレン基）、トリメチレン基、テトラメチレン基、分岐状ブタンジイル基、直鎖状又は分岐状のペンタンジイル基などを挙げることができる。−(Ｒ⁵Ｏ)_c−及び／又は−(Ｒ⁶Ｏ)_d−部分は、当該ポリオルガノシロキサンの親水性部分であって、導電性を付与すると共に、（ｂ−１）成分の電解質塩との相互作用により、アルカリ金属カチオンのイオン導電性に関与する部分である。Ｒ⁵及びＲ⁶の少なくとも一方はエチレン基又はプロピレン基であることが好ましい。ａは０〜１００の整数、ｂは１〜１００の整数を示し、ｃ及びｄは、それぞれ独立に０〜１００の整数を示すが、ｃ及びｄが同時に０であることはない。また、−(Ｒ⁴Ｏ)−と−(Ｒ⁵Ｏ)−の配列順序は任意である。
Ｒ⁷は水素原子又は一価の有機基を示す。この有機基としては、例えばメチル基、エチル基、プロピル基等の炭素数１〜５のアルキル基、アセチル基、プロピオニル基等の炭素数２〜６のアシル基が挙げられ、水酸基等の置換基を有してもよい。
前記一般式（II）で表される導電性ポリオルガノシロキサンは、例えば水素化ケイ素を有するポリオルガノシロキサン主鎖に対し、不飽和結合及びポリオキシアルキレン基を有する有機化合物をヒドロシリル化反応によりグラフトさせることによって得ることができる。

Preferred examples include compounds represented by:
In the general formula (II), R ³ represents a monovalent organic group. Examples of the monovalent organic group include an alkyl group having 1 to 4 carbon atoms such as a methyl group, an ethyl group, and a propyl group, an aryl group having 6 to 8 carbon atoms such as a phenyl group and a tolyl group, a benzyl group, and a phenethyl group. And an aralkyl group having 7 to 9 carbon atoms such as a hydroxyl group may be included.
R ^{4 to} R ⁶ each independently represent an alkylene group. Examples of the alkylene group include linear or branched alkylene groups having 1 to 8 carbon atoms such as a methylene group, an ethylene group, a propane-1,2-diyl group (propylene group), a trimethylene group, a tetramethylene group, and a branched group. And a straight-chain or branched pentanediyl group. The-(R ⁵ O) _c -and / or-(R ⁶ O) _d -moiety is a hydrophilic part of the polyorganosiloxane, imparts conductivity, and is an electrolyte salt of component (b-1) It is a part that participates in the ionic conductivity of the alkali metal cation by the interaction. At least one of R ⁵ and R ⁶ is preferably an ethylene group or a propylene group. a represents an integer of 0 to 100, b represents an integer of 1 to 100, and c and d each independently represents an integer of 0 to 100, but c and d are not 0 at the same time. Also, - (R ⁴ O) - and - (R ⁵ O) - arrangement order of the is arbitrary.
R ⁷ represents a hydrogen atom or a monovalent organic group. Examples of the organic group include alkyl groups having 1 to 5 carbon atoms such as a methyl group, an ethyl group, and a propyl group, and acyl groups having 2 to 6 carbon atoms such as an acetyl group and a propionyl group. You may have.
For example, the conductive polyorganosiloxane represented by the general formula (II) grafts an organic compound having an unsaturated bond and a polyoxyalkylene group to a polyorganosiloxane main chain having silicon hydride by a hydrosilylation reaction. Can be obtained.

In the pressure-sensitive adhesive composition of the present invention, the content of the conductive polyorganosiloxane of the component (C) that is optionally used is the component (A) from the viewpoints of antistatic resistance to peeling, adhesion, and adhesion durability. The amount is usually about 0.05 to 1 part by weight, preferably 0.1 to 0.7 part by weight, more preferably 0.12 to 0.5 part by weight, based on 100 parts by weight of the (meth) acrylic acid ester polymer. is there.
In the pressure-sensitive adhesive composition of the present invention, the content ratio of the component (B) and the component (C) is preferably 2: 8 to 9: 1 by mass ratio, and is 4: 6 to 7: 3. More preferably.
In the pressure-sensitive adhesive composition of the present invention, a crosslinking agent can be used. When this cross-linking agent is used, the (meth) acrylic acid ester polymer of the component (A) is composed of a monomer having a functional group having (meth) acrylic acid ester and active hydrogen, and other monomers used as desired. It is important to be a copolymer with a monomer. The active hydrogen portion in this copolymer is a crosslinking point.
There is no restriction | limiting in particular as this crosslinking agent, From the things conventionally used as a crosslinking agent conventionally in acrylic resin, arbitrary things can be selected suitably and can be used. Examples of such crosslinking agents include polyisocyanate compounds, epoxy resins, melamine resins, urea resins, dialdehydes, methylol polymers, aziridine compounds, metal chelate compounds, metal alkoxides, and metal salts. A compound is preferably used.
Examples of the polyisocyanate compound include aromatic polyisocyanates such as tolylene diisocyanate, diphenylmethane diisocyanate, and xylylene diisocyanate, aliphatic polyisocyanates such as hexamethylene diisocyanate, isophorone diisocyanate, and hydrogenated diphenylmethane diisocyanate. Polyisocyanates, etc., and biurets, isocyanurates, and adducts that are a reaction product with low molecular active hydrogen-containing compounds such as ethylene glycol, propylene glycol, neopentyl glycol, trimethylolpropane, castor oil, etc. Can be mentioned.

In this invention, this crosslinking agent may be used individually by 1 type, and may be used in combination of 2 or more type. The amount used depends on the type of the crosslinking agent, but is usually 0.01 to 20 parts by mass, preferably 0 with respect to 100 parts by mass of the (meth) acrylate polymer as the component (A). It is selected in the range of 1 to 10 parts by mass.
In the pressure-sensitive adhesive composition of the present invention, various additives such as a silane coupling agent, a tackifier, an antioxidant, an ultraviolet absorber, a light stabilizer, and a softening agent are provided as long as the object of the present invention is not impaired. , Fillers, colorants and the like can be included as desired.
For example, the silane coupling agent can be applied to an optical member such as a polarizing plate having a pressure-sensitive adhesive layer formed using the pressure-sensitive adhesive composition of the present invention on a glass substrate of a liquid crystal cell via the pressure-sensitive adhesive layer. Used for sticking with good adhesion even under conditions.
Examples of the silane coupling agent include triethoxysilane, vinyltris (β-methoxyethoxy) silane, γ-methacryloxypropyltrimethoxysilane, γ-glycidoxypropyltrimethoxysilane, β- (3,4- Epoxycyclohexyl) ethyltrimethoxysilane, N-β- (aminoethyl) -γ-aminopropyltrimethoxysilane, N-β- (aminoethyl) -γ-aminopropylmethyldimethoxysilane, γ-aminopropyltriethoxysilane, Examples thereof include N-phenyl-γ-aminopropyltrimethoxysilane, γ-mercaptopropyltrimethoxysilane, and γ-chloropropyltrimethoxysilane.

Further, 3-isocyanatopropyltriethoxysilane, 3-isocyanatopropyl (methyl) diethoxysilane, 2-isocyanatoethyltriethoxysilane, 2-isocyanatoethyl (methyl) diethoxysilane, 3-glycidoxypropyl Triethoxysilane, 3-glycidoxypropyl (methyl) diethoxysilane, 2-glycidoxyethyltriethoxysilane, 2-glycidoxyethyl (methyl) diethoxysilane, 3- (3,4-epoxycyclohexyl) Propyltriethoxysilane, 3- (3,4-epoxycyclohexyl) propyl (methyl) diethoxysilane, 2- (3,4-epoxycyclohexyl) ethyltriethoxysilane, 2- (3,4-epoxycyclohexyl) ethyl ( Methyl) diethoxysilane, etc., and ethoxy of these silane compounds It can also be used a silane compound obtained by replacing the methoxy group.
These silane coupling agents may be used singly or in combination of two or more. Moreover, the addition amount is about 0.001-10 mass parts normally with respect to 100 mass parts of adhesive compositions.
The pressure-sensitive adhesive composition of the present invention can provide a pressure-sensitive adhesive sheet or a pressure-sensitive optical member having good antistatic properties for peeling, adhesion and adhesion durability.
The pressure-sensitive adhesive sheet of the present invention is provided with a layer (hereinafter sometimes abbreviated as a pressure-sensitive adhesive layer) formed by using the above-mentioned pressure-sensitive adhesive composition of the present invention on at least one side of a substrate. is there. Examples of the base material include paper base materials such as glassine paper, coated paper, cast coated paper, laminated paper obtained by laminating a thermoplastic resin such as polyethylene on these paper base materials, or polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate. Polyester films such as polypropylene film, polypropylene film such as polypropylene and polymethylpentene, plastic films such as polycarbonate film and cellulose acetate film, and laminated sheets containing these films.
When the base material is plastic, the base material that has been subjected to antistatic treatment may be used. Although it does not restrict | limit especially as an antistatic process, The method of providing an antistatic layer in at least one surface of a base material, and the method of kneading a kneading-type antistatic agent in a plastic base material are used.
As a method of providing an antistatic layer on at least one surface of a base material, a method of applying an antistatic resin or a conductive polymer composed of an antistatic agent and a resin component, a conductive resin containing a conductive substance, or a conductive substance is used. Examples include vapor deposition or plating.

Antistatic agents contained in the antistatic resin include cationic antistatic agents having cationic functional groups such as quaternary ammonium salts, pyridinium salts, primary, secondary and tertiary amino groups, and sulfonic acids Anionic antistatic agents with anionic functional groups such as salts, sulfates, phosphonates, phosphates, etc., amphoteric antistatics such as alkylpetines and their derivatives, imidazolines and their derivatives, alanine and their derivatives Nonionic antistatic agents such as agents, amino alcohols and derivatives thereof, glycerin and derivatives thereof, polyethylene glycol and derivatives thereof, and monomers having ion conductive groups of the above cation type, anion type and zwitterionic type An ion conductive polymer obtained by polymerization or copolymerization may be mentioned. These compounds may be used alone or in combination of two or more.
Examples of the conductive polymer include polyaniline, polypyrrole, polythiophene, and the like. These conductive polymers may be used alone or in combination of two or more. Examples of conductive substances include tin oxide, antimony oxide, indium oxide, cadmium oxide, titanium oxide, zinc oxide, indium, tin, antimony, gold, silver, aluminum, nickel, chromium, titanium, iron, cobalt, and iodide. Copper and their alloys or mixtures.
As the resin component used for the antistatic resin and the conductive resin, for example, general-purpose resins such as polyester, acrylic, polyvinyl, urethane, melamine, and epoxy are used. In the case of a polymer type antistatic agent, it is not necessary to contain a resin component. In addition, the antistatic resin component may contain, for example, a methylolated or alkylolized melamine-based, urea-based, glyoxal-based, or acrylamide-based compound, an epoxy compound, or an isocyanate compound as a crosslinking agent.

The antistatic layer can be formed, for example, by diluting the above-described antistatic resin, conductive polymer, or conductive resin with a solvent, and applying and drying this coating liquid on a plastic substrate. Examples of the solvent include toluene, ethyl acetate, organic solvents such as 2-butanone and isopropyl alcohol, and water.
The pressure-sensitive adhesive sheet of the present invention can be used as a member for transferring a pressure-sensitive adhesive layer to an adherend, and can also be used as a member for sticking the pressure-sensitive adhesive sheet to a desired adherend. . When used for the former application, a release agent such as a silicone resin is usually applied to the surface of the substrate to which the adhesive is applied. In this case, the thickness of the substrate is not particularly limited, but is usually about 20 to 150 μm.
In the case of the latter application, the type and thickness of the substrate are selected appropriately according to the application. In this case, an ordinary release film can be provided on the pressure-sensitive adhesive layer as desired.
In the pressure-sensitive adhesive sheet of the present invention, the thickness of the pressure-sensitive adhesive layer is usually about 5 to 150 μm, preferably about 10 to 90 μm.
Next, the pressure-sensitive adhesive optical member of the present invention is obtained by providing a pressure-sensitive adhesive layer on at least one surface of a sheet-like optical member described later using the above-mentioned pressure-sensitive adhesive composition.
Although there is no restriction | limiting in particular as said sheet-like optical member, For example, a polarizing plate, a phase difference plate, an antireflection plate, a viewing angle expansion film etc. can be mentioned, Among these, a polarizing plate is especially suitable. It is. Examples of the polarizing plate include a liquid crystal display device, a light amount adjustment device, a polarization interference application device, and an optical defect detector. Among these, a polarizing plate for a liquid crystal cell in a liquid crystal display device, in particular, It is advantageous to provide an adhesive layer.

EXAMPLES Next, although an Example demonstrates this invention further in detail, this invention is not limited at all by these examples.
Various characteristics in each example were evaluated according to the following methods.
(1) Peeling voltage A polarizing plate with an adhesive layer or an adhesive sheet was cut into a width of 50 mm and a length of 100 mm, and bonded to a 2 mm thick polyethylene plate with an acrylic adhesive for fixing. This was left for 24 hours in an environment of normal temperature and humidity of 23 ° C. and humidity 50% RH, and then the release film was fixed to a high-speed peel tester [manufactured by Tester Sangyo Co., Ltd., model name “TE-701”] and peeled off. Peeling was performed under conditions of an angle of 180 ° and a peeling speed of 30 m / min.
An electric potential measuring machine [manufactured by Sicid Electric Co., Ltd.] that fixes the potential (peeling band voltage) after 5 seconds and 60 seconds after the surface of the pressure-sensitive adhesive layer generated at this time at a distance of 50 mm from the surface of the central portion of the pressure-sensitive adhesive layer. , Measured using the model name “STATIRON-DZ ₃ ”. The measurement was performed in an environment of 23 ° C. and humidity 50% RH.
In Examples 1 to 4, the polarizing plate with the pressure-sensitive adhesive layer or the pressure-sensitive adhesive sheet was used after being allowed to stand for 7 days and for 3 months in an environment of 23 ° C. and humidity 50% RH. The stripping voltage was measured.
FIG. 2 is an explanatory diagram of a method for measuring the stripping voltage in the case of the polarizing plate with the pressure-sensitive adhesive layer. In FIG. 2, 11 is a release film, 12 is an adhesive layer, 13 is a polarizing plate, 14 is an acrylic adhesive layer for fixing, 15 is a polyethylene plate, 16 is a chuck, and 17 is a potential measuring device. In the case of the pressure-sensitive adhesive sheet, the measurement was performed according to this.
(2) Adhesive strength From a polarizing plate with an adhesive layer or an adhesive sheet, a 25 mm wide and 120 mm long sample was cut out, the release film was peeled off (adhesive layer thickness 25 μm), and a soda lime glass plate [N.S. G Precision Co., Ltd., “Soda Lime Glass (without SiO ₂ coating)” was attached using a laminator to prevent air from entering, and left in an environment of 23 ° C. and humidity 50% RH for 24 hours. .
Then, using a universal tensile tester [manufactured by A & D, “Tensilon”], the polarizing plate was peeled from the glass at a peeling angle of 180 ° and a peeling speed of 0.3 m / min. Was measured.
(3) Durability After aging the polarizing plate with the pressure-sensitive adhesive layer or the pressure-sensitive adhesive sheet at 23 ° C. and a humidity of 50% RH for 1 week, a test piece having a width of 210 mm and a length of 310 mm was cut out and the same method as in (2) above. Affixed to a non-alkali glass plate [NSC Precision Co., Ltd., “Corning Glass # 1737”], and pressurized in an autoclave manufactured by Kurihara Seisakusho at 0.5 MPa, 50 ° C. for 20 minutes. went. Thereafter, after being subjected to the following conditions (a) to (c), the state of the polarizing plate was visually evaluated according to the following criteria.
○: No foaming or peeling.
X: Many foaming and peeling are observed.
<Conditions>
(A) 80 ° C., 20 days (b) 60 ° C., humidity 90% RH, 20 days (c) Heat shock: 300 cycles with 60 minutes at 30 ° C. and 30 minutes at −20 ° C.

Production Example 1
Add 97.1 parts by mass of butyl acrylate, 2.9 parts by mass of acrylic acid, and 0.2 parts by mass of 2,2′-azobisisobutyronitrile as a polymerization initiator to 200 parts by mass of ethyl acetate, and at 60 ° C. By stirring for 17 hours, an acrylic ester copolymer solution having a weight average molecular weight of 850,000 was obtained.
Production Example 2
95.4 parts by weight of butyl acrylate, 4.6 parts by weight of 2-hydroxyethyl acrylate, 0.2 part by weight of 2,2′-azobisisobutyronitrile were added to 200 parts by weight of ethyl acetate, and the mixture was heated at 60 ° C. By stirring for 17 hours, an acrylic ester copolymer solution having a weight average molecular weight of 850,000 was obtained.
Example 1
2-Butanone was added to the acrylate copolymer solution obtained in Production Example 1 to dilute to a concentration of 20% by mass. To 100 g of this solution, an ionic conductive agent represented by the general formula (I) [manufactured by Sanko Chemical Co., Ltd., trade name “0862-20R”, lithium perchlorate: adipic acid diester (A in the general formula (I) is an ethylene group) Mass ratio 20:80] 0.06 g, trimethylolpropane tolylene diisocyanate adduct as a crosslinking agent [trade name “BHS8515” manufactured by Toyo Ink Co., Ltd.] and γ-glycol as a silane coupling agent Sidoxypropyltrimethoxysilane [trade name “KBM-403” manufactured by Shin-Etsu Chemical Co., Ltd.] was added in an amount of 0.02 g to prepare a solution-like acrylic pressure-sensitive adhesive composition.
Next, this pressure-sensitive adhesive composition was applied to the release-treated surface of a release film [trade name “SP-PET3811”, manufactured by Lintec Corporation] using a knife coater, dried at 90 ° C. for 1 minute, and then thickened. A polarizing plate with an adhesive layer was produced by laminating on a 180 μm polarizing plate. The thickness of the pressure-sensitive adhesive layer was 25 μm.
The various characteristics of this polarizing plate with an adhesive layer were calculated | required. The results are shown in Table 1.
Example 2
2-Butanone was added to the acrylate copolymer solution obtained in Production Example 1 to dilute to a concentration of 20% by mass. To 100 g of this solution, an ionic conductive agent represented by the general formula (I) [manufactured by Sanko Chemical Co., Ltd., trade name “0862-20R”, lithium perchlorate: adipic acid diester (A in the general formula (I) is an ethylene group) Mass ratio 20:80] 0.03 g, conductive polyorganosiloxane represented by the general formula (II) [manufactured by Maruhishi Oil Chemical Co., Ltd., trade name “PC-3560M”, solid content 60% by mass] 0.05 g, 0.5 g of trimethylolpropane tolylene diisocyanate adduct (trade name “BHS8515” manufactured by Toyo Ink Manufacturing Co., Ltd.) as a cross-linking agent and 0.02 g of the same silane coupling agent as in Example 1 were added. An acrylic pressure-sensitive adhesive composition was prepared.
Hereinafter, a polarizing plate with an adhesive layer was prepared in the same manner as in Example 1, and various properties were obtained. The results are shown in Table 1.
Example 3
A polarizing plate film was produced in the same manner as in Example 2 except that the amount of the ionic conductive agent was changed to 0.06 g, and various characteristics were obtained. The results are shown in Table 1.
Example 4
A polarizing plate was produced in the same manner as in Example 1 except that the acrylic ester copolymer solution obtained in Production Example 2 was used, and various characteristics were obtained. The results are shown in Table 1.
Comparative Example 1
In Example 1, it implemented like Example 1 except not having added an ionic conductive agent. The results are shown in Table 1.
Comparative Example 2
In Example 1, it carried out similarly to Example 1 except having used 0.2g of cationic surfactant [the Toho Chemical Co., Ltd. make and brand name "Anstex C-200X] instead of an ionic conductive agent. Is shown in Table 1.

Example 5
A pressure-sensitive adhesive sheet was prepared in the same manner as in Example 1 except that a polyethylene terephthalate film having a thickness of 100 μm [trade name “COSMO SHINE A4100” manufactured by Toyobo Co., Ltd.] was used instead of the polarizing plate. The evaluation results of this adhesive sheet are shown in Table 2.
Example 6
A pressure-sensitive adhesive sheet was prepared in the same manner as in Example 2 except that a polyethylene terephthalate film having a thickness of 100 μm [trade name “Cosmo Shine A4100” manufactured by Toyobo Co., Ltd.] was used instead of the polarizing plate. The evaluation results of this adhesive sheet are shown in Table 2.
Example 7
A pressure-sensitive adhesive sheet was prepared in the same manner as in Example 4 except that a 100 μm thick polyethylene terephthalate film [trade name “Cosmo Shine A4100” manufactured by Toyobo Co., Ltd.] was used instead of the polarizing plate. The evaluation results of this adhesive sheet are shown in Table 2.

  As can be seen from Table 1, each of the polarizing plates with pressure-sensitive adhesive layers (Examples 1 to 4) prepared using the pressure-sensitive adhesive composition of the present invention has a peeling voltage compared to that of the comparative example. Low and excellent in adhesive strength and durability. As can be seen from Table 2, each of the pressure-sensitive adhesive sheets (Examples 5 to 7) prepared using the pressure-sensitive adhesive composition of the present invention has a low peel-off voltage and has good adhesive strength and durability. is doing.

  The pressure-sensitive adhesive composition of the present invention can provide a pressure-sensitive adhesive sheet having excellent peeling antistatic properties, adhesion, and adhesion durability, and a pressure-sensitive adhesive optical member such as a polarizing plate with a pressure-sensitive adhesive layer.

It is a perspective view which shows the structure of one example of a polarizing plate. It is explanatory drawing of the peeling voltage measuring method.

Explanation of symbols

1 Polyvinyl alcohol polarizer 2 TAC film I
2 'TAC film II
DESCRIPTION OF SYMBOLS 3 Adhesive layer 4 Release sheet 5 Surface protective film 10 Polarizing plate 11 Release film 12 Adhesive layer 13 Polarizing plate 14 Acrylic adhesive layer for fixing 15 Polyethylene plate 16 Chuck 17 Potential measuring machine

Claims (8)

  An ionic conductive agent comprising a combination of (A) (meth) acrylic acid ester polymer, and (B) (b-1) an electrolyte salt having an alkali metal cation and (b-2) an ester of a polyvalent carboxylic acid. A pressure-sensitive adhesive composition comprising:   The pressure-sensitive adhesive composition according to claim 1, further comprising (C) a conductive polyorganosiloxane.   The pressure-sensitive adhesive composition according to claim 1 or 2, comprising 0.05 to 1 part by weight of (B) and 0.05 to 1 part by weight of (C) with respect to 100 parts by weight of component (A). The (b-2) component polycarboxylic acid ester is represented by the general formula (I)
^{R 1 - [COO- (AO)} n -R 2] k ··· (I)
(Wherein R ¹ is an optionally substituted divalent to tetravalent hydrocarbon group having 2 to 15 carbon atoms, R ² is a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, or 2 to 2 carbon atoms. 6 is an acyl group, A is an alkylene group having 2 to 4 carbon atoms, k is an integer of 2 to 4, and n is an integer of 2 to 30.)
The pressure-sensitive adhesive composition according to claim 1, wherein the pressure-sensitive adhesive composition is a complete ester represented by the formula: The conductive polyorganosiloxane of component (C) has the general formula (II)

Wherein R ³ is a monovalent organic group, R ^{4 to} R ⁶ are each independently an alkylene group, R ⁷ is a hydrogen atom or a monovalent organic group, a is an integer from 0 to 100, and b is 1 to (The integer of 100, c and d each independently represents an integer of 0 to 100, but c and d are not 0 at the same time.)
The pressure-sensitive adhesive composition according to claim 2, wherein the pressure-sensitive adhesive composition is represented by the formula:   A pressure-sensitive adhesive sheet comprising a pressure-sensitive adhesive layer formed using the pressure-sensitive adhesive composition according to claim 1 on at least one side of a substrate.   An adhesive optical member comprising an adhesive layer formed using the adhesive composition according to any one of claims 1 to 5 on at least one surface of the sheet-like optical member.   The adhesive optical member according to claim 7, wherein the sheet-like optical member is a polarizing plate.

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