JP2010195941A - Antistatic pressure-sensitive adhesive - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a pressure-sensitive adhesive which excels in transparency, reduces staining of an adherend, and has sufficient antistatic performance with a small amount of an antistatic component. <P>SOLUTION: The pressure-sensitive adhesive contains a (meth)acrylate based copolymer (A) having a side chain including an onium carboxylate group (R) represented by formula (1):-CO<SB>2</SB><SP>-</SP>-Y<SP>+</SP>(wherein Y<SP>+</SP>is an onium cation) in such a manner as shown by formula (2): P-L-R, wherein the side chain is a side chain (Q) such that (R) is bonded to a polymer chain (P) of (A) by at least one covalent bond (C) selected from the group consisting of a carbon-carbon bond, a carbon-oxygen bond, a carbon nitrogen bond, and a carbon-sulfur bond, and the number k of covalent bonds (C) present in between (R) and (P) is 3-20 at the shortest distance. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an antistatic pressure-sensitive adhesive. More specifically, the present invention relates to an antistatic pressure-sensitive adhesive that has excellent antistatic properties and does not contaminate an adherend with ionic contaminants.

Conventionally, as an adhesive for the purpose of antistatic properties when peeling from an adherend, for example, an acrylic copolymer, a polyether polyol (for example, Patent Document 1), a surfactant (for example, Patent Document 2), a metal A pressure-sensitive adhesive to which an antistatic agent such as a system conductive filler and carbon black (for example, Patent Document 3) is added is known.
However, these pressure-sensitive adhesives have problems such as contamination of the surface of the adherend due to bleeding out of the antistatic agent and deterioration of the pressure-sensitive adhesive properties over time. In addition, some of these pressure-sensitive adhesives containing antistatic agents contain many impurities that can cause corrosion, malfunction, and malfunction inside electronic equipment. There is also the problem of difficulty.

In addition, there is a demand to further reduce the occurrence rate of defective products such as sucking up of surrounding dust and electrostatic breakdown due to static electricity in electronic device manufacturing, etc., and with adhesives made of these antistatic resins The antistatic property is insufficient, and further improvement of the antistatic property is demanded.
With respect to these problems, for example, a pressure-sensitive adhesive to which a metal-based conductive filler or a carbon black antistatic agent is added has a problem in that it is not transparent even if antistatic properties are satisfied.
In addition, for example, with an adhesive to which polyether polyol or a surfactant antistatic agent is added, it is extremely possible to realize antistatic properties with a surface resistivity of less than 10 ¹¹ Ω / □ without causing adherend contamination. There is a problem that it is difficult.

As a pressure-sensitive adhesive that solves these problems, for example, an alkylene oxide group (for example, Patent Document 4), a quaternary ammonium base (for example, Patent Document 5) or the like is included in the molecular side chain and / or molecular terminal of an acrylic copolymer A pressure-sensitive adhesive composed of a resin having antistatic properties is disclosed. These pressure-sensitive adhesives can realize an antistatic property with a surface resistivity of less than 10 ¹¹ Ω / □ without causing adherend contamination by incorporating an antistatic component into the polymer structure.

JP-A-6-128539 JP 58-191777 A JP 2004-307787 A JP 55-36237 A JP 2000-21535 A

However, an attempt to realize the above antistatic above, not must increase the amount of antistatic components, Therefore, there is a physical property significantly problem Sonzuru point as an adhesive, in effect, a surface resistivity of 10 ¹⁰ The limit of antistatic property was about Ω / □.
The subject of this invention is providing the adhesive which is excellent in transparency, there are few adherend body contaminations, and has sufficient antistatic performance with a small amount of antistatic component.

As a result of intensive studies to solve the above problems, the present inventors have reached the present invention that is excellent in transparency, does not cause adherend contamination, and can impart sufficient antistatic performance with a small amount of antistatic component. did.
That is, this invention contains the (meth) acrylate type copolymer (A) which has a side chain which contains the onium carboxylate group (R) shown by General formula (1) as shown by General formula (2). An adhesive, wherein the side chain is the following side chain (Q);
Side chain (Q): at least one selected from the group consisting of a polymer main chain (P) in which (R) is (A) and a carbon-carbon bond, carbon-oxygen bond, carbon-nitrogen bond, and carbon-sulfur bond A side chain in which the number k of covalent bonds (C) that are bonded by the covalent bond (C) of (R) and (P) at the shortest is 3 to 20;
_{^{-CO 2 - · Y + (1}} )
[Y ⁺ represents an onium cation. ]
PLR (2)
[(L) contains a linear, branched, aromatic or alicyclic ring which may contain an oxygen atom, a nitrogen atom and / or a sulfur atom, and is shortest between (P) and (R) A hydrocarbon group having 3 to 20 intervening covalent bonds is represented (however, they may be bonded via an oxygen atom, a nitrogen atom and / or a sulfur atom to form a heterocyclic ring)]
An adhesive composition comprising the adhesive and a crosslinking agent (B);
A pressure-sensitive adhesive layer, a pressure-sensitive adhesive film, and a pressure-sensitive adhesive sheet obtained by crosslinking the pressure-sensitive adhesive composition.

  The pressure-sensitive adhesive of the present invention is excellent in transparency, has little adherend contamination, and has sufficient antistatic performance.

The pressure-sensitive adhesive of the present invention contains a (meth) acrylate copolymer (A).
(A) has the side chain (Q) defined above among the side chains containing the onium carboxylate group (R) represented by the general formula (1) as represented by the general formula (2). Is a (meth) acrylate copolymer.
In the side chain (Q), (R) is at least selected from the group consisting of the polymer main chain (P) of (A) and a carbon-carbon bond, a carbon-oxygen bond, a carbon-nitrogen bond, and a carbon-sulfur bond. The number k of covalent bonds (C) that are bonded by one type of covalent bond (C) and that are interposed in the shortest distance between (R) and (P) is 3 to 20.
In the present invention, (meth) acrylate refers to acrylate and methacrylate.

When the number k of covalent bonds (C) is 2 or less, sufficient antistatic properties cannot be expressed, and when k is 21 or more, the (meth) acrylate copolymer (A) is polymerized with other monomers. Copolymerizability decreases.
Here, the number k of the covalent bond (C) means that the polymer main chain (P) and the carbon atom derived from the carboxylate group forming an ion pair with the onium group of the onium carboxylate group (R) are connected with the least number of bonds. This is the number of covalent bonds.

The side chain (Q) is a group containing an onium carboxylate group (R) as represented by the general formula (2). In the general formula (2), (L) contains a linear, branched, aromatic or alicyclic ring which may contain an oxygen atom, a nitrogen atom and / or a sulfur atom, and (P) and (R ) Represents a hydrocarbon group having 3 to 20 covalent bonds intervening at the shortest (but may be bonded via an oxygen atom, a nitrogen atom and / or a sulfur atom to form a heterocyclic ring). .) The functional groups contained in (L) include hydrocarbon groups, ether groups, thioether groups, carbonate groups, ester groups, imino groups, amide groups, urethane groups, urea groups, and sulfide groups. examples include, for _{example, -CH 2 -, - CH 2} CH 2 -, - CH 2 OCH 2 CH 2 -, - CH 2 SCH 2 CH 2 -, - CHO-CO-OCH 2 -, - NHCONH -, - NH—CO—O—, —CH ₂ NHCH ₂ CH _{2 -, - CH 2 NHCONH (} CH 2) 6 NHCO-O- , and _{-CH 2 S (CH 2) 2} C (= O) O (CH 2) 2 - groups with the structure of and the like. Among these, from the viewpoint of antistatic properties and adhesiveness, an ether group, a carbonate group, an ester group, and a urethane group are preferable, and an ether group and an ester group are more preferable.

The side chain (Q) is a group that is an ion pair composed of an onium cation and a carboxylate anion. A side chain (Q0) is obtained by converting the carboxylate anion group into a nonionic carboxyl group.
As a method for introducing (Q) into the (meth) acrylate copolymer (A), a side chain (Q0) containing a carboxyl group corresponding to (Q) is contained during the polymerization of (A) described later. A method in which the monomer (q0) is copolymerized and this is reacted with an onium salt.
In addition, in (A), the number k of covalent bonds (C) intervening between the onium carboxylate group (R) and the polymer main chain (P) in the shortest is the same as the carboxyl group in the corresponding monomer (q0) and polymerization. Since this is equal to the number of covalent bonds (C) intervening between the double bonds involved in, this number is also written as k.
Examples of the onium cation include a quaternary ammonium cation, a tertiary sulfonium cation, and a quaternary phosphonium cation.

Specific examples of the onium group are described below.
Examples of (I) quaternary ammonium cations include the following (I-1) to (I-12).
(I-1) Aliphatic quaternary ammonium having an alkyl and / or alkenyl group having 4 to 30 or more carbon atoms; tetramethylammonium, ethyltrimethylammonium, diethyldimethylammonium, triethylmethylammonium, trimethylethylammonium, tetraethyl Ammonium, trimethylpropylammonium, dimethyldipropylammonium, ethylmethyldipropylammonium, butyltrimethylammonium, dimethyldibutylammonium, tetrabutylammonium, tetrahexylammonium, trimethyldecylammonium, didecyldimethylammonium and the like;

(I-2) Aromatic quaternary ammonium having 6 to 30 or more carbon atoms; trimethylphenylammonium, dimethylethylphenylammonium, triethylphenylammonium and the like;

(I-3) alicyclic quaternary ammonium having 3 to 30 or more carbon atoms; N, N-dimethylpyrodinium, N-ethyl-N-methylpyrrolidinium, N, N-diethylpyrrolidinium, N, N-dimethylmorpholinium, N-ethyl-N-methylmorpholinium, N, N-diethylmorpholinium, N, N-dimethylpiperidinium, N, N-diethylpiperidinium, etc .;

(I-4) imidazolinium having 3 to 30 or more carbon atoms; 1,2,3-trimethylimidazolinium, 1,2,3,4-tetramethylimidazolinium, 1,3,4-trimethyl 2-ethylimidazolinium, 1,3-dimethyl-2,4-diethylimidazolinium, 1,2-dimethyl-3,4-diethylimidazolinium, 1,2-dimethyl-3-ethylimidazolinium 1,2,3,4-tetraethylimidazolinium, 1,2,3-triethylimidazolinium, etc .;

(I-5) imidazolium having 3 to 30 or more carbon atoms; 1,3-dimethylimidazolium, 1-ethyl-3-methylimidazolium, 1-methyl-3-ethylimidazolium, 1,2,3 -Trimethylimidazolium, 1,3-dimethyl-2-ethylimidazolium, 1,2-dimethyl-3-ethyl-imidazolium, 1,2,3-triethylimidazolium, 1,2,3,4-tetraethylimidazolium Lithium, 1,3-dimethyl-2-phenylimidazolium, 1,3-dimethyl-2-benzylimidazolium, 1-benzyl-2,3-dimethyl-imidazolium, and the like;

(I-6) Tetrahydropyrimidinium having 4 to 30 or more carbon atoms; 1,3-dimethyltetrahydropyrimidinium, 1,2,3-trimethyltetrahydropyrimidinium, 1,2,3,4-tetra Methyltetrahydropyrimidinium, 8-methyl-1,8-diazabicyclo [5,4,0] -7-undecenium, 5-methyl-1,5-diazabicyclo [4,3,0] -5-nonenium, etc .;

(I-7) C4-C30 or more dihydropyrimidinium; 1,3-dimethyl-2,4- or -2,6-dihydropyrimidinium [these are 1,3-dimethyl-2 , 4 (6) -dihydropyrimidinium, and the same expression is used hereinafter. 1,2,3-trimethyl-2,4 (6) -dihydropyrimidinium, 1,2,3,4-tetramethyl-2,4 (6) -dihydropyrimidinium, 1,2,3 5-tetramethyl-2,4 (6) -dihydropyrimidinium, 8-methyl-1,8-diazabicyclo [5,4,0] -7,9 (10) -undecadienium, 5-methyl- 1,5-diazabicyclo [4,3,0] -5,7 (8) -nonadienium, etc .;

(I-8) Guanidinium having an imidazolinium skeleton having 3 to 30 or more carbon atoms; 2-dimethylamino-1,3,4-trimethylimidazolinium, 2-diethylamino-1,3,4-trimethylimidazole Linium, 2-diethylamino-1,3-dimethyl-4-ethylimidazolinium, 2-dimethylamino-1-methyl-3,4-diethylimidazolinium, and the like;

(I-9) Guanidinium having an imidazolium skeleton having 3 to 30 or more carbon atoms; 2-dimethylamino-1,3,4-trimethylimidazolium, 2-diethylamino-1,3,4-trimethylimidazolium, 2-diethylamino-1,3-dimethyl-4-ethylimidazolium, 2-diethylamino-1-methyl-3,4-diethylimidazolium, etc .;

(I-10) Guanidinium having a tetrahydropyrimidinium skeleton having 4 to 30 or more carbon atoms; 2-dimethylamino-1,3,4-trimethyltetrahydropyrimidinium, 2-diethylamino-1,3,4- Trimethyltetrahydropyrimidinium, 2-diethylamino-1,3-dimethyl-4-ethyltetrahydropyrimidinium, and the like;

(I-11) Guanidinium having a dihydropyrimidinium skeleton having 4 to 30 or more carbon atoms; 2-dimethylamino-1,3,4-trimethyl-2,4 (6) -dihydropyrimidinium, 2- Diethylamino-1,3,4-trimethyl-2,4 (6) -dihydropyrimidinium, 2-dimethylamino-1-methyl-3,4-diethyl-2,4 (6) -dihydropyrimidinium, etc. .

(I-12) Quaternary salt pyridinium cations of the following heterocyclic compounds, such as N-methylpyridinium;
Pyridazinium cations, such as N-methylpyridazinium;
Pyrimidinium cations such as N-methylpyrimidinium;
Pyrazinium cations, such as N-methylpyrazinium;
Pyrazolium cations such as N-methylpyrazolium;
Thiazolium cations such as N-methylthiazolium;
An oxazolium cation, such as N-methyloxazolium;
Triazolium cations, such as N-methyltriazolium.

(II) Examples of the tertiary sulfonium cation include the following (II-1) to (II-3).
(II-1) Aliphatic tertiary sulfonium having an alkyl and / or alkenyl group having 1 to 30 or more carbon atoms; trimethylsulfonium, triethylsulfonium, ethyldimethylsulfonium, diethylmethylsulfonium and the like;
(II-2) Aromatic tertiary sulfonium having 6 to 30 or more carbon atoms; phenyldimethylsulfonium, phenylethylmethylsulfonium, phenylmethylbenzylsulfonium and the like;
(II-3) An alicyclic tertiary sulfonium having 3 to 30 or more carbon atoms; methylthiolanium, phenylthiolanium, methylthianium, etc .;

(III) Examples of the quaternary phosphonium cation include the following (III-1) to (III-3).
(III-1) Aliphatic quaternary phosphonium having an alkyl group and / or alkenyl group having 1 to 30 or more carbon atoms; tetramethylphosphonium, tetraethylphosphonium, tetrapropylphosphonium, tetrabutylphosphonium, methyltriethylphosphonium, methyl Tripropylphosphonium, methyltributylphosphonium, dimethyldiethylphosphonium, trimethylethylphosphonium, trimethylpropylphosphonium, ethyltripropylphosphonium, ethyltributylphosphonium, diethyldibutylphosphonium, triethylbutylphosphonium, propyltributylphosphonium, dipropyldibutylphosphonium, tripropylbutylphosphonium etc;
(III-2) Aromatic quaternary phosphonium having 6 to 30 or more carbon atoms; triphenylmethylphosphonium, diphenyldimethylphosphonium, triphenylbenzylphosphonium and the like;
(III-3) alicyclic quaternary phosphonium having 3 to 30 or more carbon atoms; 1,1-dimethylphosphonium, 1-methyl-1-ethylphosphonium, 1,1-diethylphosphonium, 1,1-dimethylphosphorinanium, 1-methyl-1-ethylphosphorinanium, 1,1-diethylphosphorinanium, 1,1-pentamethylenephosphorinanium, etc .;

Of these, preferred are quaternary ammonium cations, and more preferred are aliphatic ammonium having 4 to 30 or more carbon atoms, imidazolinium having 3 to 30 or more carbon atoms, and 3 to 3 carbon atoms. 30 or more imidazoliums, particularly preferred are trimethylethylammonium, dimethyldiethylammonium, triethylmethylammonium, didecyldimethylammonium, 1,2,3,4-tetramethylimidazolinium, 1,2- Dimethyl-3-ethylimidazolinium, 1-ethyl-3-methylimidazolium, and 1-methyl-3-ethylimidazolium. One or two or more of these onium cations may be used.

Specific examples of the side chain (Q) include the following.
1. Side chain (Q1) represented by the following general formula (3)

In General formula (3), F is a C2-C4 alkylene group and an ethylene group is preferable. n is an integer of 1 to 4, but is limited to a range where k is 3 to 20.
For example, when F is an ethylene group and n = 1, a side chain of k = 9 can be mentioned.
(Q1) can be introduced by (co) polymerizing the monomer (q01) represented by the following general formula (4). (Q01) can be obtained by adding succinic anhydride to an alkylene oxide adduct of (meth) acrylic acid.

一般式（４）において、Ｆ、ｎは一般式（３）と同じである。Ｒ’は水素、又はメチル基である。

In general formula (4), F and n are the same as in general formula (3). R ′ is hydrogen or a methyl group.

一般式（５）において、Ｆは炭素数２〜４のアルキレン基であり、エチレン基が好ましい。Ｇは炭素数２〜７のアルキレン基であり、ペンタメチレン基が好ましい。ｎは１〜３の整数であるが、ｋが３〜２０である範囲に限られる。
例えば、Ｆがエチレン基、Ｇがペンタメチレン基、ｎ=１の場合であって、ｋ＝１６の側鎖が挙げられる。
（Ｑ２）は、下記一般式（６）で表されるモノマー（ｑ０２）を（共）重合することにより導入することができる。（ｑ０２）は（メタ）アクリル酸のアルキレンオキサイド付加物にラクトンを付加させ、さらに無水コハク酸を付加させることにより得ることが出来る。ラクトンとしては、炭素数３〜８のラクトンが挙げられ、カプロラクトンが好ましい。 2. Side chain (Q2) represented by the following general formula (5)

In General formula (5), F is a C2-C4 alkylene group and an ethylene group is preferable. G is an alkylene group having 2 to 7 carbon atoms, preferably a pentamethylene group. n is an integer of 1 to 3, but is limited to a range where k is 3 to 20.
For example, when F is an ethylene group, G is a pentamethylene group and n = 1, a side chain of k = 16 can be mentioned.
(Q2) can be introduced by (co) polymerizing the monomer (q02) represented by the following general formula (6). (Q02) can be obtained by adding a lactone to an alkylene oxide adduct of (meth) acrylic acid and further adding succinic anhydride. Examples of the lactone include lactones having 3 to 8 carbon atoms, and caprolactone is preferable.

一般式（６）において、Ｆ、Ｇ、ｎは一般式（５）と同じである。Ｒ’は水素、又はメチル基である。

In General formula (6), F, G, and n are the same as General formula (5). R ′ is hydrogen or a methyl group.

3. Side chain introduced by (co) polymerization of vinyl benzoic acid (Q3) (k = 3 to 5 depending on the isomer)
The (meth) acrylate copolymer (A) may have one kind or two or more kinds of side chains (Q).

  In the present invention, the (meth) acrylate copolymer (A) is preferably 0.05 mol / 1000 g based on the weight of (A), from the viewpoint of antistatic property of the pressure-sensitive adhesive (Q). Above, more preferably 0.2 mol / 1000 g or more, particularly preferably 0.3 mol / 1000 g or more. Further, from the viewpoint of the tackiness of the pressure-sensitive adhesive, the content is preferably 1.8 mol / 1000 g or less, more preferably 1.0 mol / 1000 g or less, and particularly preferably 0.8 mol / 1000 g or less. (Q) If the content is 0.05 mol / 1000 g or less, sufficient antistatic properties cannot be expressed, and if it is 1.8 mol / 1000 g or more, the tackiness is lowered.

Tg [measurement method: DSC (scanning differential thermal analysis) method] of the (meth) acrylate copolymer (A) is preferably −100 ° C., more preferably −90 ° C. from the viewpoint of the adhesive strength of the adhesive. In particular, the upper limit is preferably −80 ° C., and from the viewpoint of tackiness of the pressure-sensitive adhesive, the upper limit is preferably 30 ° C., more preferably 0 ° C., and particularly preferably −10 ° C.
Since the Tg of (A) can be predicted from the monomer used, a polymer having a Tg of −100 ° C. to 30 ° C. can be synthesized by appropriately selecting the monomer to be used.
Weight average molecular weight of (A) [Hereinafter abbreviated as Mw, measurement is based on gel permeation chromatography (GPC) method (polystyrene conversion). ] Is preferably 5,000, more preferably 15,000, particularly preferably 50,000 from the viewpoint of the cohesive strength of the pressure-sensitive adhesive, and 2,000,000, preferably upper limit from the viewpoint of the viscosity of the coating liquid. It is preferably 1,800,000, particularly preferably 1,200,000.

As described above, the (meth) acrylate copolymer (A) is synthesized from the (meth) acrylate copolymer (A0) containing a carboxyl group as a precursor.
(A0) includes hydrocarbyl (meth) acrylate (a01) and, if necessary, an ethylenically unsaturated group-containing monomer having a carboxyl group (a02) [however, it is different from the monomer (q0), and k is 1 or 2 and k may be 21 or more. Those in which k is 1 are preferred. ] Other ethylenically unsaturated group-containing monomer (a03), ethylenically unsaturated group having a functional group having an active hydrogen atom that can react with the crosslinking agent (B) (for example, hydroxyl group, amino group, methylol group and amide group) A copolymer having the containing monomer (a04) as a structural unit is included.
In (A), the molar ratio of the monomers (a01) and (a03) is preferably 100: 0 to 50:50, more preferably 97: 3 to 75:25.
In (A0), (q0) is preferably contained in an amount of 0.04 to 4.7 mol / 1000 g, more preferably 0.07 to 3.7 mol / 1000 g.
In (A0), (a02) is preferably contained in an amount of 0 to 3.0 mol / 1000 g, more preferably 0.5 to 2.5 mol / 1000 g.
In (A), the onium carboxylate group derived from (a02) is preferably contained in an amount of 0 to 2.5 mol / 1000 g, more preferably 0.3 to 2.0 mol / 1000 g.
In (A), the group derived from (a04) is preferably contained in an amount of 0 to 0.5 mol / 1000 g, more preferably 0.1 to 0.3 mol / 1000 g.

  Hydrocarbyl (meth) acrylate (a01) contains 3 or more carbon atoms (hereinafter abbreviated as C) and 2,000 or less number average molecular weight (hereinafter abbreviated as Mn), for example, the following (a011) to (a012) It is. Here, hydrocarbyl represents a hydrocarbon group that may contain a hetero atom such as an oxygen atom or a nitrogen atom. The Mn is a value determined by gel permeation chromatography (GPC) method (polystyrene conversion) in the same manner as the weight average molecular weight (hereinafter abbreviated as Mw) described later.

(A011) Hydrocarbyl (meth) acrylate not containing a heteroatom Hydrocarbyl group not containing a heteroatom is an aliphatic [C1-25 (preferably 4-18), such as an alkyl group [methyl, ethyl, n- And i-propyl, n-, i-, sec- and t-butyl, n-, i-, sec-, t- and neopentyl, n-octyl, 2-ethylhexyl, nonyl, decyl, lauryl, tridecyl, myristyl, Cetyl and stearyl groups, etc.], alkenyl groups [ethenyl, propenyl, butenyl, hexenyl, decenyl and oleyl groups, etc.]], alicyclic [C4-18, eg cyclobutyl, cyclopentyl and cyclohexyl groups], araliphatic [C7-18]. Benzyl and phenylethyl groups] and aromatic [C6-1 5, for example a phenyl group] carbyl group, etc .;

(A012) Nitrogen-containing (meth) acrylate (1) Tertiary nitrogen-containing (meth) acrylate Dialkyl (C1-4) aminoalkyl (C1-4) (meth) acrylate [N, N-dimethylaminoethyl (meth) acrylate, Diethylaminoethyl (meth) acrylate, t-butylaminoethyl (meth) acrylate, etc.], heterocyclic-containing (meth) acrylate [morpholinoethyl (meth) acrylate, etc.] and the like.
(3) Nitrile group-containing (meth) acrylate C5-15, such as cyanoalkyl (C1-4) (meth) acrylate.

  Of the above (a01), from the viewpoint of tackiness, adhesive strength and cohesive strength of the pressure-sensitive adhesive, (a011) is preferable, and n-butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate and n-octyl are more preferable. (Meth) acrylate.

  Examples of the ethylenically unsaturated group-containing monomer (a02) having a carboxyl group include monobasic acids [C3-10, such as (meth) acrylic acid, crotonic acid, cinnamic acid], dibasic acids [C4-8, such as maleic acid. , Itaconic acid, fumaric acid, citraconic acid and mesaconic acid], monoesters of dibasic acids [monohydrocarbyl (C1-18) esters of the above dibasic acids], and mixtures of two or more of these .

Examples of the other ethylenically unsaturated group-containing monomer (a03) include the following.
(A031) Unsaturated hydrocarbon (1) Aliphatic unsaturated hydrocarbon C2-18 or more olefin [ethylene, propylene, butene, isobutylene, pentene, heptene, diisobutylene, octene, dodecene, octadecene, etc.], C4- 10 or more dienes [butadiene, isoprene, 1,4-pentadiene, 1,6-hexadiene, 1,7-octadiene, etc.] and the like (2) alicyclic unsaturated hydrocarbons C4-18 or more alicyclic rings Containing unsaturated hydrocarbons such as cyclohexene, (di) cyclopentadiene, pinene, limonene, indene (3) aromatic ring containing unsaturated hydrocarbons C8-20 or more aromatic ring containing unsaturated hydrocarbons such as styrene, α- Methylstyrene, vinyltoluene, 2,4-dimethylstyrene, ethylstyrene, Isopropyl styrene, butyl styrene, phenyl styrene, cyclohexyl styrene, benzyl styrene

(A032) Vinyl ester, vinyl ether, vinyl ketone, unsaturated dicarboxylic acid diester (1) Vinyl ester (1-1) Aliphatic vinyl ester (C4-15, such as vinyl acetate, vinyl butyrate, vinyl propionate, vinyl butyrate, diallyl Adipate, isopropenyl acetate, vinyl methoxyacetate, vinyl benzoate)
(1-2) Aromatic vinyl ester (C9-20, such as diallyl phthalate, methyl-4-vinylbenzoate, acetoxystyrene)

(2) Vinyl ether (2-1) Aliphatic vinyl ether C3-15, for example, vinyl alkyl (C1-10) ether [vinyl methyl ether, vinyl butyl ether, vinyl 2-ethylhexyl ether, etc.], vinyl alkoxy (C1-6) alkyl ( C1-4) ether [vinyl-2-methoxyethyl ether, methoxybutadiene, 3,4-dihydro-1,2-pyran, 2-butoxy-2′-vinyloxydiethyl ether, vinyl-2-ethylmercaptoethyl ether, etc. ], Poly (2-4) (meth) allyloxyalkane (C2-6) [diallyloxyethane, triaryloxyethane, tetraallyloxybutane, tetrametaallyloxyethane, etc.]
(2-2) Aromatic vinyl ether C8-20, such as vinyl phenyl ether, phenoxystyrene

(3) Vinyl ketone (3-1) Aliphatic vinyl ketone C4-25, such as vinyl methyl ketone, vinyl ethyl ketone (3-2) Aromatic vinyl ketone C9-21, such as vinyl phenyl ketone (4) Unsaturated dicarboxylic acid diester C4 34 unsaturated dicarboxylic acid diesters such as di (cyclo) alkyl fumarate, di (cyclo) alkyl maleate [in each case two (cyclo) alkyl groups are C1-22 linear, branched or Represents an alicyclic group. ]

  Of those exemplified as (a03) above, (1) in (a032) is preferable from the viewpoint of tackiness, adhesive strength and cohesive strength of the pressure-sensitive adhesive.

Examples of the ethylenically unsaturated group-containing monomer (a04) having an active hydrogen atom capable of reacting with the crosslinking agent (B) include the following.
(A041) hydroxyl group-containing compound (1) C5-12 unsaturated carboxylic acid ester (1-1) hydroxyalkyl (C2-6) (meth) acrylate [hydroxyethyl-, hydroxypropyl- and hydroxybutyl (meth) acrylate, etc. And lactones thereof (C4-20, such as butyrolactone, valerolactone, caprolactone and laurolactone) 1-5 mol adduct (1-2) poly (n = 2-30) oxyalkylene (C2-4) (meth) Acrylate [poly (n = 10) oxyethylene mono (meth) acrylate, etc.]
(1-3) Poly (n = 2-30) oxyalkylene (C2-4) unsaturated carboxylic acid diester [poly (n = 10) oxyethylenemaleic acid diester, etc.], poly (n = 2-30) oxyalkylene (C2-4) (meth) allyl ether [poly (n = 10) oxyethylene (meth) allyl ether, etc.]
(2) C3-8 unsaturated alcohol [(meth) allyl alcohol, crotyl alcohol, 1-butene-3-ol, 2-butene-1,4-diol, etc.]
(3) C8-15 styrene compound [hydroxystyrene and the like]
(4) C5-20 ether [hydroxyalkyl (C2-6) alkenyl (C3-6) ether such as 2-hydroxyethylpropenyl ether]
(5) methylol group-containing compounds [C4-10 hydroxyl group-containing (meth) acrylamide [N-methylol (meth) acrylamide etc.] etc.] and the like;

(A042) Amino group-containing compound (1) C5-15 primary-secondary amino group-containing (meth) acrylate aminoalkyl (C2-6) (meth) acrylate [aminoethyl (meth) acrylate etc.], alkyl ( C1-6) aminoalkyl (C1-6) (meth) acrylate [t-butylaminoethyl methacrylate etc.] etc. (2) primary and secondary amino group-containing (meth) acrylamides of C5-10 N-aminoalkyl ( C2-6) (meth) acrylamide [eg N-aminoethyl (meth) acrylamide, (meth) acrylamide alkyl (C2-6) alkyl (C1-6) amine [eg (meth) acrylamidoethylbutylamine] etc. (3) alkenyl Amine compounds C3-15, such as mono- and di- (meth) allylamine, chloro Triethanolamine and the like;

(A043) Etherified product of hydroxymethyl group-containing compound Alkyl (C1-4) etherified product of C4-10 hydroxyl group-containing (meth) acrylamide [N-butoxymethyl (meth) acrylamide etc.]
(A044) Amide group-containing vinyl compound (1) C3-30 (meth) acrylamide compound (meth) acrylamide, N-alkyl (C1-6) (meth) acrylamide [N-methyl (meth) acrylamide, N-butyl ( Meth) acrylamide etc.], N, N-dihydrocarbyl [alkyl (C1-6) and / or aralkyl (C7-15)] (meth) acrylamide [N, N-dimethylacrylamide, N, N-dibenzylacrylamide] Etc.], diacetone acrylamide, etc. (2) C4-20 amide group-containing vinyl compounds excluding the above (meth) acrylamide compounds (meth) acrylformamide, N-methyl-N-vinylacetone amide, cyclic amide (N-vinyl) Pyrrolidone, etc.).

(A045) Nitrogen-containing monomer (1) Tertiary (meth) acrylamide compound of C3-20 (1-1) Tertiary nitrogen-containing (meth) acrylamide compound Dimethylaminoethyl (meth) acrylamide, diethylaminoethyl (meth) acrylamide, etc. (2) Heterocycle-containing vinyl compound Pyridine compound (C7-14, such as 2- and 4-vinylpyridine), imidazole compound (C5-12, such as N-vinylimidazole), pyrrole compound (C6-13, such as N-vinyl) Pyrrole) etc.

  Of those exemplified as (a04) above, (1) in (a041) is preferable from the viewpoint of tackiness, adhesive strength and cohesive strength of the pressure-sensitive adhesive.

The production method of (A0) is not particularly limited, and a known method can be used, but a radical polymerization method is preferable, and a solution polymerization method is preferable because the molecular weight is easily adjusted.
Solvents used in solution polymerization include esters (C2-8, such as ethyl acetate, butyl acetate), alcohols (C1-8, such as methanol, ethanol, octanol), hydrocarbons (C4-8, such as n-butane, cyclohexane). , Toluene), ketone (C3-9, such as methyl ethyl ketone), and the like.

In the present invention, the (meth) acrylate copolymer (A) may have a —CH ₂ CH ₂ O— unit (E). When (A) has (E), based on the weight of (A), the —CH ₂ CH ₂ O— unit (E) is preferably 0.15 from the viewpoint of the antistatic property of the pressure-sensitive adhesive. Mole / 1000 g or more, more preferably 0.2 mol / 1000 g or more. Further, from the viewpoint of insufficient cohesive force of the pressure-sensitive adhesive and contaminating the adherend, it is preferably 6.0 mol / 1000 g or less, more preferably 3.0 mol / 1000 g or less, and particularly preferably 1.0 mol / 1000 g. Contains below.

The group having —CH ₂ CH ₂ O— unit (E) is a polyoxyalkylene having an average number of repetitions of 5 to 30, preferably 50 to 100% by weight, more preferably based on the weight of the polyoxyalkylene. Contains 75 to 100% by weight of —CH ₂ CH ₂ O— units. Examples of oxyalkylene other than —CH ₂ CH ₂ O— unit (E) include 1,2-oxypropylene, 1,2-oxybutylene, 1,4-oxybutylene, and 1-phenyl-1,2-oxyethylene. It is done.

As a method for introducing —CH ₂ CH ₂ O— unit (E) into (A),
(1) After polymerizing (A), (E) by reacting the carboxyl group in the molecular chain of (A) with the compound (g) having (E) and a group that reacts with the carboxyl group. How to introduce,
(2) A method of copolymerizing a monomer having (E), that is, a method of copolymerizing a (meth) acrylate monomer having a —CH ₂ CH ₂ O— unit (E) in the molecule.
The introduction method (E) may be carried out independently or in combination with (1) and (2), but the method (1) is preferred.

The pressure-sensitive adhesive of the present invention does not have a side chain (Q), and the number k of covalent bonds (C) interposed between the onium carboxylate group (R) and the polymer main chain (P) in the shortest is 1 or 2. A (meth) acrylate copolymer (A1) having a side chain (S) and / or —CH ₂ CH ₂ O— unit (E), or any group of (R) and (E). The (meth) acrylate copolymer (A2) not to be contained may be further contained.

The (meth) acrylate copolymer (A2) is composed of a hydrocarbyl (meth) acrylate (a01), an ethylenically unsaturated group-containing monomer (a02) having a carboxyl group, and other ethylenically unsaturated group-containing monomers. It can be obtained as a copolymer having (a03) or the like as a structural unit.
The (meth) acrylate copolymer (A1) is a carboxyl group-containing (meth) acrylate copolymer (A2) with an onium carboxylate group (R) and / or —CH ₂ CH ₂ O— unit (E). It is obtained by granting.

  The (meth) acrylate copolymer (A), the (meth) acrylate copolymer (A1), and the (meth) acrylate copolymer (A2) may be mixed in any ratio, but preferably (A ) / [(A1) + (A2)] = 27/73 to 99/1, more preferably 50/50 to 99/1, and particularly preferably 70/30 to 99/1.

When the (meth) acrylate copolymer (A) has a weight average molecular weight of 5,000 to 100,000, (A) has a weight average molecular weight of 200,000 to 3,000,000 (meth). The pressure-sensitive adhesive of the present invention is preferably composed of a mixture with the acrylate copolymer (A1) and / or the (meth) acrylate copolymer (A2).

  In the antistatic pressure-sensitive adhesive of the present invention, a tackifier resin (J1), a plasticizer (J2), a filler (J3), a pigment (J4), a pigment as necessary, as long as the effects of the present invention are not impaired. At least one additive (J) selected from the group consisting of an ultraviolet absorber (J5), an antioxidant (J6) and a silane coupling agent (J7) can be further added. As specific examples of (J1) to (J6), those described in JP-A-2008-7702 can be used.

  Examples of the silane coupling agent (J7) include polymerizable unsaturated group-containing silicon compounds (vinyltrimethoxysilane, vinyltriethoxysilane, methacryloxypropyltrimethoxysilane, etc.), epoxy group-containing silicon compounds [3-glycidoxypropyl Trimethoxysilane, 2- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, etc.], amino group-containing silicon compound [3-aminopropyltrimethoxysilane, N- (2-aminoethyl) -3-aminopropyltrimethoxy Silane, N- (2-aminoethyl) -3-aminopropylmethyldimethoxysilane and the like], 3-chloropropyltrimethoxysilane and the like, and mixtures thereof.

  The pressure-sensitive adhesive used in the pressure-sensitive adhesive layer, pressure-sensitive adhesive film and pressure-sensitive adhesive sheet of the present invention is prepared by mixing the pressure-sensitive adhesive (X) of the present invention, the cross-linking agent (B) and, if necessary, the additive (J) with an ordinary mixing device (stirring device It is preferable to manufacture by mixing uniformly in a mixing tank, a static mixer or the like provided. (B) is preferably mixed immediately before application to the film or sheet of the adhesive film or adhesive sheet, and (J) is the stage of production of the pressure-sensitive adhesive (X) of the present invention (raw material before production, reaction product during production). Alternatively, it may be added in the product after production).

Among the film-like pressure-sensitive adhesive layer, pressure-sensitive adhesive film, and pressure-sensitive adhesive sheet of the present invention, the film-shaped pressure-sensitive adhesive layer has a mold-release property such as a release film using various coating apparatuses. It is applied directly to at least a part of at least one side of a substrate having a catalyst, heated to dry the solvent or dispersion medium, and preferably the reaction between the (meth) acrylate copolymer (A) and the crosslinking agent (B) It can be manufactured by a method of proceeding and further curing and curing.
In addition, the adhesive film and the adhesive sheet are applied directly to at least a part of at least one side of the substrate using the adhesive of the present invention using various coating apparatuses, heated to dry the solvent or dispersion medium, Preferably, the reaction of the (meth) acrylate copolymer (A) and the crosslinking agent (B) is allowed to proceed, followed by curing and curing, or after the adhesive is similarly applied to a release film, etc., and then dried. The pressure-sensitive adhesive thus obtained can be produced in a film form, a sheet form or a tape form by a method of transferring to at least one side of the substrate.
Examples of the coating apparatus include a gravure coater, a roll coater, a reverse coater, a doctor blade, a bar coater, a comma coater, a fountain die coater, a lip coater, and a knife coater.
Base materials include films, sheets, foams and flat yarns of various plastics [polyolefin (polyethylene, polypropylene, etc.), polyurethane, polyethylene terephthalate, polyvinyl chloride, rayon, polyamide resin, etc.], paper (Japanese paper, crepe paper, etc.) , Metal plate or metal foil, woven fabric, non-woven fabric, wood and the like.
Among these base materials, those that are easily charged are desirably provided with antistatic properties by adding or coating various antistatic agents.

Examples of the heating means for curing the pressure-sensitive adhesive of the present invention include hot air (60 to 150 ° C.), (near) infrared light, and high frequency.
Moreover, as said curing conditions, about 3 to 7 days at room temperature or about 12 to 72 hours at 45 degreeC is mentioned, for example.
The coating thickness after drying / curing of the pressure-sensitive adhesive is usually from 1 to 250 μm, and preferably from 10 to 100 μm from the viewpoint of adhesive strength, drying and curability.

  The present invention will be described more specifically with reference to the following examples, but the present invention is not limited thereto. Hereinafter, the part means part by weight.

[Production of pressure-sensitive adhesive comprising a (meth) acrylate copolymer (A) having a quaternary ammonium group and a —CH ₂ CH ₂ O— unit]
Example 1
Into a reaction vessel equipped with a stirrer, a thermometer, a reflux condenser, a dropping funnel and a nitrogen gas introduction tube, 349.1 parts of ethyl acetate was charged, and the temperature was raised to 78 ° C. Subsequently, 380 parts of n-butyl acrylate (a01-1), 20 parts of 2-acryloyloxyethyl succinic acid (q0-1) (k value 9), 50.9 parts of ethyl acetate, and 2,2 ′ are added to the dropping funnel. -0.4 parts of azobis (2,4-dimethylvaleronitrile) was charged to obtain a uniform mixed solution. The dropping funnel was attached to the reaction vessel, and continuously dropped into the reaction vessel over 4 hours while passing nitrogen gas to cause radical polymerization. After completion of the addition, the mixture was aged for 3 hours. Thereafter, 149.1 parts of ethyl acetate was added as a diluent solvent to obtain a solution of an acrylate copolymer (A0-1) having a carboxyl group.
In 100 parts of a solution of (A0-1), 1.3 parts of didecyldimethylammonium monomethyl carbonate (z1-1), 0.9 parts of lauryl alcohol EO15 mol glycidyl ether compound (g1-1), and ethyl acetate 37 An acrylate copolymer having a quaternary ammonium group and a —CH ₂ CH ₂ O— unit (A—) by adding 1 part and reacting at a reaction temperature of 80 ° C. for 8 hours and removing by-product carbon dioxide gas. An antistatic pressure-sensitive adhesive (X-1) comprising the solution of 1) was obtained. The viscosity of (X-1) (B-type viscometer: 25 ° C., the same shall apply hereinafter) is 500 mPa · s, the solid content concentration is 30.1%, and Mw by GPC method of (A-1) (polystyrene conversion, the same applies hereinafter). ) Was 350,000.

Example 2
In Example 1, instead of 1.3 parts of didecyldimethylammonium monomethyl carbonate (z1-1), 0.9 part of lauryl alcohol EO15 mol glycidyl ether compound (g1-1), and 44.9 parts of ethyl acetate , (Z1-1) 5.7 parts, and acrylate copolymer having a quaternary ammonium group by removing carbon dioxide generated as a by-product, except that 5.7 parts of ethyl acetate and 36.2 parts of ethyl acetate were used. An antistatic pressure-sensitive adhesive (X-2) comprising a solution of the combined (A-2) was obtained. The viscosity of (X-2) was 800 mPa · s, the solid content concentration was 30.3%, and the Mw of (A-2) was 340,000.

Example 3
In Example 1, in place of 380 parts of n-butyl acrylate and 20 parts of 2-acryloyloxyethyl succinic acid, 320 parts of n-butyl acrylate and 80 parts of 2-acryloyloxyethyl succinic acid were used. It carried out like Example 1 and obtained the acrylate copolymer (A0-2) which has a carboxyl group.
Next, to 100 parts of the solution of (A0-2), 12.6 parts of didecyldimethylammonium monomethyl carbonate (z1-1), 8.8 parts of lauryl alcohol EO15 mol glycidyl ether compound (g1-1), and acetic acid 62.1 parts of ethyl was added, and the same procedure as in Example 1 was followed, and the antistatic property comprising a solution of an acrylate copolymer (A-3) having a quaternary ammonium group and a —CH ₂ CH ₂ O— unit. An adhesive (X-3) was obtained. The viscosity of (X-3) was 600 mPa · s, the solid content concentration was 30.3%, and the Mw of (A-3) was 340,000.

Comparative Example 1
In Example 1, it replaced with 380 parts of n-butyl acrylate and 20 parts of 2-acryloyloxyethyl succinic acid, and carried out similarly to Example 1 except having used 380 parts of n-butyl acrylate and 20 parts of acrylic acid. The acrylate copolymer (A2-1) which has a carboxyl group was obtained. In 100 parts of a solution of (A2-1), 1.1 parts of didecyldimethylammonium monomethyl carbonate (z1-1), 0.9 parts of lauryl alcohol EO15 mol glycidyl ether compound (g1-1), and ethyl acetate 37 .1 parts was added, the reaction temperature of 80 for 8 hours and reacted at ° C., by-produced acrylate copolymer having a quaternary ammonium group and _-CH 2 _CH 2 O- units by removing carbon dioxide (A1- An antistatic pressure-sensitive adhesive (X′-1) comprising the solution 1) was obtained. The viscosity of (X′-1) was 500 mPa · s, the solid content concentration was 30.1%, and the Mw of (A1-1) was 320,000.

Comparative Example 2
In Comparative Example 1, instead of 1.3 parts didecyldimethylammonium monomethyl carbonate (z1-1), 0.9 parts lauryl alcohol EO15 mol glycidyl ether compound (g1-1), and 44.9 parts ethyl acetate , (Z1-1) 5.9 parts, and acrylate copolymer having a quaternary ammonium group by removing carbon dioxide produced as a by-product, except that 9.2 parts of ethyl acetate and 37.2 parts of ethyl acetate were used. An antistatic pressure-sensitive adhesive (X′-2) comprising a solution of the combined (A1-2) was obtained. The viscosity of (X′-2) was 840 mPa · s, the solid content concentration was 30.1%, and the Mw of (A1-2) was 340,000.

Comparative Example 3
In Comparative Example 1, instead of 1.3 parts didecyldimethylammonium monomethyl carbonate (z1-1), 0.9 parts lauryl alcohol EO15 mol glycidyl ether compound (g1-1), and 44.9 parts ethyl acetate , (Z1-1) 4.9 parts, (g1-1) 10.6 parts and ethyl acetate 61.3 parts were used in the same manner as in Example 1, except that carbon dioxide generated as a by-product was removed. An antistatic pressure-sensitive adhesive (X′-3) comprising a solution of an acrylate copolymer (A1-3) having a quaternary ammonium group and a —CH ₂ CH ₂ O— unit was obtained. The viscosity of (X′-3) was 740 mPa · s, the solid content concentration was 30.1%, and the Mw of (A1-3) was 340,000.

Comparative Example 4
In Comparative Example 1, instead of 1.3 parts didecyldimethylammonium monomethyl carbonate (z1-1), 0.9 parts lauryl alcohol EO15 mol glycidyl ether compound (g1-1), and 44.9 parts ethyl acetate , (G1-1) An acrylate having a —CH ₂ CH ₂ O— unit by carrying out in the same manner as in Example 1 except that 2.6 parts of ethyl acetate and 39.5 parts of ethyl acetate were used, and removing carbon dioxide generated as a by-product. An antistatic pressure-sensitive adhesive (X′-4) comprising a solution of the copolymer (A1-4) was obtained. The viscosity of (X′-4) was 540 mPa · s, the solid content concentration was 30.1%, and the Mw of (A1-4) was 360,000.

Comparative Example 5
In Comparative Example 1, instead of 1.3 parts didecyldimethylammonium monomethyl carbonate (z1-1), 0.9 parts lauryl alcohol EO15 mol glycidyl ether compound (g1-1), and 44.9 parts ethyl acetate , (Z1-1) 15.1 parts and ethyl acetate 44.9 parts were used in the same manner as in Example 1, except that by-produced carbon dioxide gas was removed, and the acrylate copolymer having a quaternary ammonium group was obtained. An antistatic pressure-sensitive adhesive (X′-5) comprising a solution of the polymer (A1-5) was obtained. The viscosity of (X′-5) was 480 mPa · s, the solid content concentration was 30.1%, and the Mw of (A1-5) was 350,000.

Comparative Example 6
To 100 parts of a solution of carboxyl group-containing acrylate copolymer (A2-1), 2.0 parts of lithium perchlorate, polyether diol [trade name “Sanix PP-400”, manufactured by Sanyo Chemical Industries, Ltd.] 9.0 parts and 22.1 parts of ethyl acetate were blended to obtain a comparative antistatic pressure-sensitive adhesive (X′-6). The viscosity of (X′-6) was 450 mPa · s, and the solid content concentration was 30.1%.

Example 4
In Example 1, instead of 380 parts of n-butyl acrylate, 20 parts of 2-acryloyloxyethyl succinic acid, and 0.4 part of 2,2′-azobis (2,4-dimethylvaleronitrile), n-butyl Carrying out the carboxyl group in the same manner as in Example 1 except that 200 parts of acrylate, 200 parts of 2-acryloyloxyethyl succinic acid, and 40 parts of 2,2′-azobis (2,4-dimethylvaleronitrile) were used. The obtained acrylate copolymer (A0-3) was obtained.
Next, 63.0 parts of didecyldimethylammonium monomethyl carbonate (z1-1) and 75.0 parts of ethyl acetate were added to 100 parts of the solution of (A0-3), and the same procedure as in Example 1 was performed. An acrylate copolymer (A-4) having a quaternary ammonium group was obtained. The viscosity of (A-4) was 2.1 mPa · s, the solid content concentration was 30.3%, and the Mw of (A-4) was 15,000.
Furthermore, 20 parts of (A-4) and 80 parts of acrylate copolymer (A1-1) were mixed to obtain an antistatic pressure-sensitive adhesive (X-4). The viscosity of (X-4) was 400 mPa · s, and the solid content concentration was 30.3%.

Example 5
In Example 4, instead of 63.0 parts didecyldimethylammonium monomethyl carbonate (z1-1) and 75.0 parts ethyl acetate, 1-ethyl-3-methylimidazolium monomethyl carbonate (z1- 2) An acrylate copolymer (A-5) having a quaternary ammonium group was obtained in the same manner as in Example 4 except that 58.2 parts and 64.7 parts of ethyl acetate were used. The viscosity of (A-5) was 1.7 mPa · s, the solid content concentration was 30.3%, and the Mw of (A-5) was 15,000.
Furthermore, 20 parts of (A-5) and 80 parts of acrylate copolymer (A1-1) were mixed to obtain an antistatic pressure-sensitive adhesive (X-5). The viscosity of (X-5) was 440 mPa · s, and the solid content concentration was 30.3%.

Example 6
In Example 5, in place of 80 parts of the acrylate copolymer (A1-1), 80 parts of (A2-1) was used in the same manner as in Example 1, and the antistatic pressure-sensitive adhesive (X-6) was used. ) The viscosity of (X-6) was 400 mPa · s, and the solid content concentration was 30.4%.

Example 7
In Example 5, in place of 80 parts of the acrylate copolymer (A1-1), 80 parts of (A1-4) was used in the same manner as in Example 1, and the antistatic pressure-sensitive adhesive (X-7) ) The viscosity of (X-7) was 400 mPa · s, and the solid content concentration was 30.4%.

Example 8
N, N, N ′, N′-tetraglycidylxylylenediamine (trade name “TETRAD-X” manufactured by Mitsubishi Gas Chemical Industries, Ltd.) as a cross-linking agent was added to 100 parts of the antistatic adhesive (X-1). 1 part of a 10% toluene solution was added and mixed uniformly to prepare a blended solution. This mixed solution was applied to a release polyester film [Lintec Co., Ltd., trade name “Superstec SP-PET38”] so that the film thickness after drying was 40 μm, and the coating solution was 100 minutes at 60 ° C. for 100 minutes. Each was dried with hot air at 1 ° C. for 1 minute, further cured at 45 ° C. for 3 days, and then peeled off from the release polyester film to obtain a pressure-sensitive adhesive layer (a film made of only a pressure-sensitive adhesive without a base material, the same applies hereinafter).
In the above, “Super Tech” was replaced with a polyester film [trade name “Lumirror” type T, manufactured by Toray Industries, Inc.], and the above mixture was coated on the film so that the film thickness was 25 μm after drying. In the same manner as described above, a pressure-sensitive adhesive film (a film composed of a base material and a pressure-sensitive adhesive; the same applies hereinafter) was obtained. The pressure-sensitive adhesive layer or pressure-sensitive adhesive film was evaluated according to the following performance evaluation method. The contents of the obtained sample are shown in Table 1. The evaluation results are shown in Table 2.

Examples 9-14
Using the antistatic pressure-sensitive adhesives (X-2) to (X-7), the same operation as in Example 8 was performed to prepare a pressure-sensitive adhesive layer or a pressure-sensitive adhesive film, and each performance was evaluated. The contents of the obtained sample are shown in Table 1. The evaluation results are shown in Table 2.

Comparative Examples 7-12
The same operation as in Example 8 was performed using the antistatic pressure-sensitive adhesives (X′-1) to (X′-6), and a pressure-sensitive adhesive layer or a pressure-sensitive adhesive film was prepared to evaluate each performance. The contents of the obtained sample are shown in Table 1. The evaluation results are shown in Table 2.

（１）（メタ）アクリレート系共重合体（A）の重量に基づく、側鎖(Q)由来の4級アンモニウム基濃度
（２）（メタ）アクリレート系共重合体（Ａ）、（A１）又は（Ａ２）の重量に基づく、側鎖(Ｓ)由来の4級アンモニウム基濃度
（３）（メタ）アクリレート系共重合体（Ａ）、（A１）又は（Ａ２）の重量に基づく、−ＣＨ_２ＣＨ_２Ｏ−単位(Ｅ)含有量

(1) Concentration of quaternary ammonium group derived from side chain (Q) based on weight of (meth) acrylate copolymer (A) (2) (meth) acrylate copolymer (A), (A1) or Concentration of quaternary ammonium group derived from side chain (S) based on weight of (A2) (3) Based on weight of (meth) acrylate copolymer (A), (A1) or (A2), -CH ₂ CH ₂ O-unit (E) content

[Performance test method]
(4) Contamination to adherend surface Adhesive film test piece of 50 × 100 mm area is attached to a stainless steel plate, and left to stand for 1 week under the condition of 60 ° C. × 90% RH. The presence or absence of contamination such as cloudiness and adhesive residue on the surface was observed with the naked eye and evaluated according to the following criteria.
○: Neither cloudy or adhesive residue △: Slightly cloudy or adhesive residue ×: Remarkably cloudy or adhesive residue

(5) Antistatic properties (surface resistivity)
After the pressure-sensitive adhesive layer test piece was allowed to stand for 12 hours under the condition of 23 ° C. × 65% RH, the surface resistivity and volume resistivity were evaluated by the method described in JIS-K6911.

(6) Adhesive strength Adhesive film test piece was affixed to a stainless steel plate (SUS304, the same shall apply hereinafter) so that the affixing area would be 25 mm wide × 100 mm long [one reciprocation with 2 kg load roller, and so on. ] Adhesive strength at normal temperature (23 ° C.) according to JIS-Z-0237 for 30 minutes after pasting (initial) and after 30 minutes after pasting, heat treated at 60 ° C. for 1 week (after heating promotion) (Unit: N / 25 mm) was evaluated. The rate of increase in adhesive strength is the rate of increase in adhesive strength after heating from the initial adhesive strength.

From the results of Table 1, the antistatic pressure-sensitive adhesive of the present invention exhibits high antistatic performance despite the use of the same amount of cation and nonion as compared with the comparative example. (Examples 1-3, Comparative Examples 1-3).
Further, in Examples 4 and 5, the antistatic pressure-sensitive adhesives (X′-1) and (X′-4) of Comparative Example 1 were mixed, and in Example 7, the antistatic pressure-sensitive adhesive of the present invention was mixed with Comparative Example 4. However, it exhibits high antistatic properties without deteriorating adherend contamination and adhesive properties.
Comparative Example 6 has 0.37 mol / 1000 g of lithium perchlorate that is used as an additive for imparting antistatic properties. Compared with 5, the side chain (Q) of the present invention has better antistatic properties and adherend contamination properties.

Since the antistatic pressure-sensitive adhesive of the present invention exhibits a large antistatic performance with a small amount of a cation component, the problems caused by the addition of the cation component so far, such as instability of adhesive force after heating, are solved. Generally, when the addition amount of the cation component is increased, there is a problem that the rate of increase in adhesive strength after heating increases and the reliability decreases. For example, Examples 4, 5, and 7 have antistatic performance equal to or higher than that of Comparative Example 5, but each has a small addition amount of a cation component, so that the rate of increase in adhesive strength after heating is small, and heat resistance stability is improved. Excellent.
As described above, the antistatic pressure-sensitive adhesive of the present invention can be used alone as a pressure-sensitive adhesive, but it can be used as an antistatic property-imparting agent with little adherend contamination when added to an existing pressure-sensitive adhesive. it can.

The antistatic pressure-sensitive adhesive of the present invention includes various optical members such as a polarizing plate, a retardation plate and a light diffusion plate, a surface protective film such as stainless steel and plastic, a tape for processing electronic parts such as a dicing tape and a carrier tape, and a polarizing plate. It can be used in a wide variety of applications such as various optical members such as retardation plates and light diffusion plates, and various image display devices such as liquid crystal displays, organic EL displays, plasma displays, and field emission displays.

Claims (11)

A pressure-sensitive adhesive containing a (meth) acrylate copolymer (A) having a side chain containing an onium carboxylate group (R) represented by the general formula (1) as represented by the general formula (2), The pressure-sensitive adhesive is characterized in that the side chain is the following side chain (Q).
Side chain (Q): at least one selected from the group consisting of a polymer main chain (P) in which (R) is (A) and a carbon-carbon bond, carbon-oxygen bond, carbon-nitrogen bond, and carbon-sulfur bond -CO ₂ ⁻ · Y ⁺ (1) wherein the number k of the covalent bonds (C) that are bonded by the covalent bond (C) of (R) and (P) at the shortest is 3 to 20
[Y ⁺ represents an onium cation. ]
PLR (2)
[(L) contains a linear, branched, aromatic or alicyclic ring which may contain an oxygen atom, a nitrogen atom and / or a sulfur atom, and is shortest between (P) and (R) A hydrocarbon group having 3 to 20 intervening covalent bonds is represented (however, they may be bonded via an oxygen atom, a nitrogen atom and / or a sulfur atom to form a heterocyclic ring)] The pressure-sensitive adhesive according to claim 1, wherein in the general formula (1), the onium group is a quaternary ammonium group. Furthermore, the pressure-sensitive adhesive according to claim 1 or 2 having a (meth) acrylate copolymer (A) is _-CH 2 _CH 2 O-units (E). The general formula (2), wherein the side chain of the (meth) acrylate copolymer (A) represented by -LR is represented by the general formula (3). The adhesive as described in.

[F is an alkylene group having 2 to 4 carbon atoms, n is an integer of 1 to 4, and k is 3 to 20. ]   The pressure-sensitive adhesive according to any one of claims 1 to 4, having a glass transition temperature of -100 to 30 ° C and a weight average molecular weight of 5,000 to 3,000,000. Side chain (S) which has no side chain (Q) and the number k of covalent bonds (C) interposed between onium carboxylate group (R) and polymer main chain (P) at the shortest is 1 or 2 And / or a (meth) acrylate copolymer (A1) having a -CH ₂ CH ₂ O-unit (E), or a (meth) acrylate system that does not have any of the groups (R) and (E). The pressure-sensitive adhesive according to any one of claims 1 to 5, further comprising a copolymer (A2). The (meth) acrylate copolymer (A) has a weight average molecular weight of 5,000 to 100,000, and the (meth) acrylate copolymer (A1) and the (meth) acrylate copolymer (A2). The pressure-sensitive adhesive according to claim 6, having a weight average molecular weight of 200,000 to 3,000,000. A pressure-sensitive adhesive composition comprising the pressure-sensitive adhesive according to any one of claims 1 to 7 and a crosslinking agent (B). A pressure-sensitive adhesive layer having a thickness of 1 to 100 μm, which is obtained by crosslinking the pressure-sensitive adhesive composition according to claim 8. The adhesive film formed by apply | coating the adhesive composition of Claim 8 to at least one part of at least one side of a base material, and bridge | crosslinking. The adhesive sheet formed by apply | coating the adhesive composition of Claim 8 to at least one part of at least one side of a base material, and bridge | crosslinking.