JP2009173721A - Antistatic acrylic pressure-sensitive adhesive and antistatic pressure-sensitive adhesive film using the pressure-sensitive adhesive - Google Patents

Abstract

PROBLEM TO BE SOLVED: To adhere to an optical film with good adhesion, and after the optical film is attached to an adherend, in the case of a large area, even if it is exposed to a high temperature for a long period of time, no light leakage phenomenon occurs and the area is small. Is pressure sensitive adhesive that can form a pressure sensitive adhesive layer that does not foam, float or peel off at the sticking interface even when exposed to high temperatures for a long period of time, has excellent reworkability, and is less likely to be charged during peeling. To provide an agent.
SOLUTION: A copolymer (C) having a hydroxyl group and / or a carboxyl group and having a glass transition temperature of −60 to 0 ° C. and a compound (D) having a functional group capable of reacting with a hydroxyl group and / or a carboxyl group. And a boron compound having a specific structure, wherein the copolymer (C) comprises a high molecular weight component (A) and a low molecular weight component (B), and the area of both in GPC The ratio is (A) / (B) = 60/40 to 90/10.
[Selection figure] None

Description

  The present invention relates to an antistatic acrylic pressure-sensitive adhesive and an antistatic pressure-sensitive adhesive film using the pressure-sensitive adhesive. Specifically, the present invention relates to a pressure-sensitive adhesive that is suitably used when an optical film is attached to an adherend such as glass. More specifically, the present invention relates to a pressure-sensitive adhesive that can form a peelable adhesive film without contaminating an adherend even if it is placed under high temperature and high pressure, high temperature, and high temperature and high humidity after sticking.

  In recent years, display devices have been used in household and commercial appliances such as electronic computers, electronic watches, mobile phones, and televisions, in-vehicle devices, etc., and there have been many opportunities to be used under various and severe conditions. ing. And various optical films, such as a polarizing film and a phase difference film, are used for the display member which comprises these display apparatuses.

Various optical films such as a polarizing film and a retardation film are attached to an adherend (glass or other optical film constituting a liquid crystal cell) using a pressure-sensitive adhesive. Specifically, the release sheet covering the surface of the pressure-sensitive adhesive layer was peeled off from the pressure-sensitive adhesive film in a laminated state of various optical films / pressure-sensitive adhesive layers / release sheets, and the pressure-sensitive adhesive layer was removed. Then, a polarizing film, a retardation film or the like is attached to a liquid crystal cell glass which is an adherend.
When peeling off the release sheet, static electricity may be generated, and the static electricity sucks dust and debris at the time of sticking. Liquid crystals and electronic circuits that are stopped may be damaged.

Furthermore, after sticking a polarizing film or retardation film to the adherend liquid crystal cell glass, etc., in the inspection process, problems with the sticking state (such as air or dust trapping during sticking) were discovered. In such a case, the polarizing film or retardation film is peeled off from glass or the like, and a new polarizing film or retardation film is attached. This re-pasting operation is called “rework”.
At the time of reworking, it is required that the pressure-sensitive adhesive layer does not remain on the adherend surface. Furthermore, static electricity may be generated when various optical films such as a polarizing film and a retardation film are peeled off, and the static electricity may damage liquid crystals and electronic circuits.

  As described above, the pressure-sensitive adhesive used for laminating a polarizing film on a glass member for a liquid crystal cell has good optical properties (transparency), heat resistance and moist heat resistance, good stress relaxation, refraction. Controllability of the rate, removability, etc. are required. And the same performance is calculated | required also for the pressure sensitive adhesive for laminating | stacking the retardation film and the cover film of various displays.

  By the way, the polarizing film is a state in which a polyvinyl alcohol film dyed and stretched with a pigment is sandwiched between a triacetyl cellulose-based protective film or a cycloolefin-based protective film. The triacetyl cellulose-based protective film and the cycloolefin-based protective film used for the polarizing film have poor adhesion. In addition, the polarizing film has poor dimensional stability due to the characteristics of these materials, and the dimensional change due to the shrinkage of the film is severe under high temperature or high temperature and high humidity conditions.

When a laminate composed of an optical film / pressure-sensitive adhesive layer / adherent is placed under high temperature or high temperature / humidity conditions and the dimensions of the optical film change, the interface between the pressure-sensitive adhesive layer and the adherend Bubbles are generated (foaming), and the optical film is lifted from the adherend and peeled off.
By adjusting the molecular weight of the main component of the pressure-sensitive adhesive used and the degree of crosslinking of the pressure-sensitive adhesive and increasing the adhesive strength, it resists changes in the dimensions of the optical film and foams, floats and floats even in harsh environments. Attempts have been made in the past to prevent peeling.

  However, if an attempt is made to resist the dimensional change of the optical film simply by increasing the adhesive force, the stress distribution due to the dimensional change of the optical film that occurs under high temperature or high temperature and high humidity conditions becomes non-uniform, and the optical film Concentrate on the four corners or on the peripheral edges. As a result, when the optical film is a polarizing film used in a liquid crystal display device, there is a problem that a so-called “light leakage phenomenon” occurs in which light leaks from the four corners and peripheral edges of the liquid crystal display device.

  Therefore, even under harsh conditions, it is a pressure-sensitive adhesive for optical film sticking that does not cause foaming at the interface with the adherend and does not lift or peel off. It does not cause light leakage and has excellent optical properties. Various pressure sensitive adhesives have been proposed.

  A high molecular weight (meth) acrylic copolymer having a weight average molecular weight of 1 million or more, which is a copolymer of an alkyl (meth) acrylate and a polymerizable monomer having functionality for a crosslinking agent, and a weight average An adhesive composition for a polarizing plate comprising a low molecular weight (meth) acrylic copolymer having a molecular weight of 30,000 or less, and a polyfunctional compound having at least two functional groups capable of forming a crosslinked structure in the molecule, and this adhesion A polarizing plate having an adhesive layer formed from an agent composition has been proposed (see Patent Document 1).

  Furthermore, a pressure-sensitive adhesive layer containing a (meth) acrylic resin and a dye is provided on one surface of the light transmissive film, and the (meth) acrylic resin has a high molecular weight body having a weight average molecular weight of 200,000 or more. A colored pressure-sensitive adhesive-attached film for electronic displays, which is composed of a low molecular weight material having a weight average molecular weight of less than 200,000 and has a functional group, has been proposed (see Patent Document 2).

  Furthermore, as a resin component, (A) (meth) acrylic acid ester homopolymer or copolymer having a weight average molecular weight of 500,000 to 2,000,000, and (B) (meth) acrylic acid having a weight average molecular weight of 5,000 or more and less than 500,000. And a (meth) acrylic acid ester copolymer having a nitrogen-containing functional group in the molecule, wherein at least one of the component (A) and the component (B) includes an ester homopolymer or a copolymer. A pressure-sensitive adhesive has been proposed (Patent Document 3).

  Furthermore, a copolymer having a weight average molecular weight of 1,000,000 to 2,000,000, which is obtained by radical copolymerization of a monomer having a reactive functional group and another monomer, and a carboxyl group in the presence of the copolymer. A copolymer (B) having a weight average molecular weight of 10,000 or more and 100,000 or less, and the copolymer (A) and / or the copolymer ( A pressure-sensitive adhesive composed of a polyfunctional compound having at least two reactive functional groups capable of reacting with B), and a pressure-sensitive adhesive layer composed of the pressure-sensitive adhesive are formed on at least one surface of the optical member; An optical member has been proposed (Patent Document 4).

  Furthermore, a pressure-sensitive adhesive comprising an alkyl (meth) acrylate copolymer, an antioxidant and a curing agent, in which the gel fraction of the pressure-sensitive adhesive is adjusted has been proposed (Patent Document 5). .

All of the pressure-sensitive adhesive films using the pressure-sensitive adhesives described in Patent Documents 1 to 5 are exposed to an adherend for a long time under high temperature and high pressure, high temperature, and high temperature and high humidity. However, foaming does not occur at the sticking interface with the adherend, no float or peeling occurs, and no light leakage phenomenon occurs.
However, the polarizing film using the pressure-sensitive adhesive described in Patent Documents 1 to 5 is pasted on an adherend such as glass, and after being exposed to high temperature and high pressure, high temperature, and high temperature and high humidity, the film is reattached. In this case, since the adhesion between the pressure sensitive adhesive and the glass as the adherend is increased, the pressure sensitive adhesive may remain on the glass as the adherend.
In the past, after being exposed to high temperature and high pressure, high temperature, high temperature and high humidity, it will not be peeled off, and after confirming the defect immediately after bonding, there was no problem if rework was possible, From the viewpoint of shortening the work process and recycling, the required properties for rework have increased because of the increasing number of cases where the polarizing film is peeled off after exposure to high temperature and high pressure, high temperature and high temperature and high humidity.

  Accordingly, the present inventors have actively used alkyl methacrylate (a1) having no specific amount of substituents in response to strict requirements for antistatic properties, durability, reworkability after exposure to high temperature and high humidity, and the like. A pressure-sensitive adhesive containing an acrylic copolymer used and a copolymer exhibiting a specific molecular weight distribution has been proposed (see Japanese Patent Application No. 2007-278732). Alkyl methacrylate (a1) having no substituent stiffens the acrylic copolymer formed, and thus has not been used so actively in the field of pressure-sensitive adhesives. By controlling the alkyl methacrylate (a1), the requirements for durability and reworkability after exposure to high temperature and high humidity could be satisfied.

By the way, there are cases where severe requirements are imposed on light leakage rather than durability, like an optical film for a large screen display. The pressure-sensitive adhesive containing an acrylic copolymer using a specific amount of alkyl methacrylate (a1) having no substituent cannot satisfy the strict requirement for light leakage.
On the other hand, the in-vehicle display is placed at a higher temperature than a display premised on indoor use, and therefore, more severe requirements are imposed on durability.
JP-A-10-279907 JP 2002-372619 A JP 2001-89731 A JP 2004-331697 A JP 2003-49143 A

One object of the present invention is that the adhesiveness to an optical film is good, and even when the area is larger, a light leakage phenomenon occurs even if the optical film is attached to an adherend and exposed to a high temperature for a long period of time. Pressure-sensitive adhesive that is difficult to cause static electricity when peeling off the release sheet and during rework after being exposed to a high temperature for a long period of time, hardly leaves dirt on the adherend, and can form a pressure-sensitive adhesive layer; And providing a pressure-sensitive adhesive film using the pressure-sensitive adhesive.
Another object of the present invention is good adhesion to the optical film. After the optical film is attached to the adherend, even if the optical film is exposed to a high temperature for a long period of time, foaming does not occur at the attachment interface, and the film does not float or peel off. Pressure-sensitive type that is less likely to occur, is less likely to generate static electricity when peeling off the release sheet and during rework after being exposed to high temperatures for a long period of time, does not leave dirt on the adherend, and can form a pressure-sensitive adhesive layer An object of the present invention is to provide an adhesive and a pressure-sensitive adhesive film using the pressure-sensitive adhesive.

The present invention is represented by a copolymer (C) having a hydroxyl group and / or a carboxyl group and having a glass transition temperature of −60 to 0 ° C., an isocyanate curing agent (D), and the following general formula [1]. An antistatic acrylic pressure-sensitive adhesive containing a compound (E1) or a compound (E2) represented by the following general formula [2]:
The copolymer (C) is
<2> A high molecular weight component (A) and a low molecular weight component (B) are included (provided that the copolymer (C) is copolymerized with 5 to 35% by weight of an alkyl methacrylate having no substituent (note that , The total of the monomers constituting the copolymer (C) is 100% by weight)),
<2-1> A peak of a high molecular weight component (A1) having a weight average molecular weight of 500,000 to 2,200,000 completely independent on an emission curve in gel permeation chromatography, and a low weight average molecular weight of 1,000 to 100,000 The area ratio between the peak of the high molecular weight component (A1) and the peak of the low molecular weight component (B1) is (A1) / (B1) = 60 / 40-90. / 10, or
<2-2> The peak of the high molecular weight component (A2) having a weight average molecular weight of 500,000 to 2,200,000 and a weight average molecular weight of 1,000 to 100,000 located on both sides of the minimum value of the discharge curve in gel permeation chromatography The area ratio of the peak of the high molecular weight component (A2) to the peak of the low molecular weight component (B2) is (A2) / (B2) = 60/40. ~ 90/10, or <2-3> gel permeation chromatography comprising a polymer molecule having a molecular weight of 150,000 or more, and having a weight average molecular weight of 500,000 to 2,200,000 of a high molecular weight component (A3) A peak of a low molecular weight component (B3) composed of polymer molecules having a molecular weight of less than 150,000 and having a weight average molecular weight of 1,000 to 100,000, and the high molecular weight component (A3) And (A3) / (B3) = 60/40 to 90/10, wherein the ratio of the area between the peak and the low molecular weight component (B3) peak is an antistatic acrylic pressure-sensitive adhesive .

(In General Formula (1) and General Formula (2), R ¹ to R ⁸ are each independently a hydrogen atom, an alkyl group that may have a substituent, an alkenyl group that may have a substituent, An alkynyl group that may have a substituent, an aryl group that may have a substituent, or a heterocyclic group that may have a substituent, wherein R ⁵ to R ⁸ are adjacent to each other You may form a ring with
In the general formula (2), A ⁺ represents an alkali metal ion. )

According to a second invention, R ^{1 to} R ⁴ are each independently an alkyl group which may have a substituent or an aryl group which may have a substituent. Relates to a pressure-sensitive acrylic pressure sensitive adhesive.

The third invention relates to the antistatic acrylic pressure-sensitive adhesive according to the first invention or the second invention, wherein R ^{1 to} R ⁴ are each independently an aryl group which may have a substituent. .

The fourth invention is the antistatic acrylic pressure-sensitive adhesive according to any one of the first to third inventions, wherein R ^{5 to} R ⁸ are each independently an alkyl group which may have a substituent. It relates to the agent.

  5th invention contains 0.01-10 weight part of compounds (D) which have a functional group which can react with a hydroxyl group or a carboxyl group with respect to 100 weight part of copolymers (C). The present invention relates to an antistatic acrylic pressure-sensitive adhesive according to any one of the first to fourth inventions.

  The sixth invention relates to the antistatic acrylic pressure-sensitive adhesive according to any one of claims 1 to 6, wherein the hydroxyl group-containing monomer is hydroxyalkyl (meth) acrylate.

  The seventh invention relates to the antistatic acrylic pressure-sensitive adhesive according to claim 7, wherein the alkyl chain of hydroxyalkyl (meth) acrylate has 3 to 20 carbon atoms.

  In the eighth invention, the copolymer (C) has an alkyl (meth) acrylate (a) having neither a hydroxyl group nor a carboxyl group, a hydroxyl group and / or a carboxyl group, and an ethylenically unsaturated double bond. The monomer (b) and, if necessary, other radically polymerizable monomers (c) other than the above (a) and (b) are radically copolymerized until the polymerization conversion becomes 60 to 90%, and the weight A copolymer containing a high molecular weight component having an average molecular weight of 500,000 to 2,200,000 is obtained, and then at least one of the above (a), (b) and (c) is added, and the polymerization conversion rate becomes 80 to 100%. Further, the present invention relates to an antistatic acrylic pressure-sensitive adhesive according to any one of the first to seventh inventions, which is obtained by radical copolymerization.

The ninth invention relates to an alkyl (meth) acrylate (a) having neither a hydroxyl group nor a carboxyl group, a monomer (b) having a hydroxyl group and / or a carboxyl group and an ethylenically unsaturated double bond, and If necessary, the radically polymerizable monomer (c) other than the above (a) and (b) is radically copolymerized until the polymerization conversion becomes 60 to 90%, and the weight average molecular weight is 500,000 to 2,200,000. To obtain a copolymer containing a high molecular weight component of
Next, at least one of the above (a), (b) and (c) is added, and radical copolymerization is further carried out until the polymerization conversion becomes 80 to 100%. <2-1> On the discharge curve in gel permeation chromatography A completely independent high molecular weight component (A1) having a weight average molecular weight of 500,000 to 2,200,000 and a low molecular weight component (B1) peak having a weight average molecular weight of 1,000 to 100,000, the high molecular weight component The area ratio of the peak of the body (A1) and the peak of the low molecular weight component (B1) is (A1) / (B1) = 60/40 to 90/10, or
<2-2> The peak of the high molecular weight component (A2) having a weight average molecular weight of 500,000 to 2,200,000 and a weight average molecular weight of 1,000 to 100,000 located on both sides of the minimum value of the discharge curve in gel permeation chromatography The area ratio of the high molecular weight component (A2) peak to the low molecular weight component (B2) peak is (A2) / (B2) = 60/40 to 90 / Or in <2-3> gel permeation chromatography, a peak of a high molecular weight component (A3) consisting of polymer molecules having a molecular weight of 150,000 or more and having a weight average molecular weight of 500,000 to 2,200,000, A peak of a low molecular weight component (B3) consisting of polymer molecules having a molecular weight of less than 150,000 and having a weight average molecular weight of 1,000 to 100,000, and the peak of the high molecular weight component (A3) The area ratio to the low molecular weight component (B3) peak is (A3) / (B3) = 60/40 to 90/10.
A copolymer (C) having a hydroxyl group and / or a carboxyl group and having a glass transition temperature of −60 to 0 ° C. is obtained (excluding the case where 5 to 35% by weight of an alkyl methacrylate having no substituent is copolymerized ( The total amount of monomers constituting the copolymer (C) is 100% by weight.)), And then the copolymer (C) and a compound having a functional group capable of reacting with a hydroxyl group or a carboxyl group ( D) and a compound (E1) represented by the following general formula (1) or a compound (E2) represented by the following general formula (2) are mixed, and antistatic acrylic pressure-sensitive adhesive The present invention relates to a method for producing an agent.

(In General Formula (1) and General Formula (2), R ¹ to R ⁸ are each independently a hydrogen atom, an alkyl group that may have a substituent, an alkenyl group that may have a substituent, An alkynyl group that may have a substituent, an aryl group that may have a substituent, or a heterocyclic group that may have a substituent, wherein R ⁵ to R ⁸ are adjacent to each other You may form a ring with
In the general formula (2), A ⁺ represents an alkali metal ion. )

  A tenth invention relates to an antistatic acrylic pressure-sensitive adhesive obtained by the production method according to the ninth invention.

  An eleventh invention is an antistatic acrylic pressure-sensitive adhesive layer formed from the antistatic acrylic pressure-sensitive adhesive according to any one of the first to eighth inventions or the tenth invention, The present invention relates to an antistatic acrylic pressure-sensitive adhesive film which is provided on at least one surface of an optical film selected from the group consisting of a polarizing film and a retardation film.

  According to the present invention, the adhesiveness to the optical film is good. After the optical film is attached to the adherend, foaming occurs at the adhesive interface even if it is exposed to high temperature and high pressure, high temperature or high temperature and high humidity for a long time. Pressure-sensitive adhesive that can form a pressure-sensitive adhesive layer that not only floats and peels off, does not cause light leakage, but also has excellent reworkability and is less likely to be charged during peeling, and the pressure-sensitive adhesive It became possible to provide a pressure-sensitive adhesive film comprising

The antistatic acrylic pressure-sensitive adhesive of the present invention will be described.
The copolymer (C) used in the antistatic acrylic pressure-sensitive adhesive of the present invention is a main component of the pressure-sensitive adhesive, and reacts with the isocyanate-based curing agent (D) described later to produce a pressure-sensitive type. An adhesive layer is formed.
The copolymer (C) contains <2> a high molecular weight component (A) and a low molecular weight component (B). (However, the case where the copolymer (C) is copolymerized with 5 to 35% by weight of an alkyl methacrylate having no substituent (excluding the total of the monomers constituting the copolymer (C) is 100% by weight) )))

This copolymer (C) has the following three types according to the form indicated by the discharge curve of gel permeation chromatography (hereinafter referred to as “GPC”).
<2-1> A type in which the high molecular weight component (A1) and the low molecular weight component (B1) form a completely independent peak on GPC.
<2-2> A type in which a high molecular weight component (A2) and a low molecular weight component (B2) exhibit a continuous peak connected by a minimum value on a GPC discharge curve. The high molecular weight side is defined as the high molecular weight component (A2) and the low molecular weight side is defined as the low molecular weight component (B2) with the minimum value as a boundary. In many cases, the minimum value is between about 20,000 and 200,000 molecular weight.
<2-3> A type in which the high molecular weight component (A3) and the low molecular weight component (B3) show a continuous peak on the GPC emission curve and do not have a clear minimum value. In this case, with the molecular weight of 150,000 as the boundary, the high molecular weight side is the high molecular weight component (A3) and the low molecular weight side is the low molecular weight component (B3).

  The high molecular weight component (A) and the low molecular weight component (B) contained in the copolymer (C) are classified and specified as any one of the above <2-1> to <2-3>, Any of (A1) and (B1), (A2) and (B2), (A3) and (B3). In any specific method, the high molecular weight component (A) has a weight average molecular weight of 500,000 to 2,200,000, and the low molecular weight component (B) has a weight average molecular weight of 1,000 to 100,000. The area ratio of the component (A) peak to the low molecular weight component (B) peak is (A) / (B) = 60/40 to 90/10.

The alkyl (meth) acrylate (a) having neither a hydroxyl group nor a carboxyl group that constitutes the copolymer (C) used in the present invention is an alkyl in which the alkyl group in the ester part does not have these functional groups. It means that it is a group. The alkyl group may be linear, may have a branched structure, or may have a cyclic structure. It is preferable that carbon number of this alkyl group is 1-6 from a reactive (polymerizable) viewpoint.
Alkyl (meth) acrylate is an abbreviation for alkyl acrylate or alkyl methacrylate.

  Examples of the alkyl methacrylate (a1) and alkyl acrylate (a2) having neither a hydroxyl group nor a carboxyl group include methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, isopropyl (meth) acrylate, n-butyl (meth) acrylate, n-pentyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, n-hexyl (meth) acrylate, cyclohexyl (meth) acrylate, n-heptyl (meth) acrylate, n-octyl ( Mention may be made of (meth) acrylate, isooctyl (meth) acrylate, n-nonyl (meth) acrylate, n-decyl (meth) acrylate, undecyl (meth) acrylate, dodecyl (meth) acrylate and the like. These may be used alone or in appropriate combination of two or more.

  Next, as the copolymer (C) used in the present invention, a monomer (b) having a hydroxyl group and / or a carboxyl group and having an ethylenically unsaturated double bond may be mentioned.

As the monomer (b) having a hydroxyl group and an ethylenically unsaturated double bond, (meth) acrylates having a hydroxyl group in an alkyl chain leading to an ester bond, such as (meth) acrylic acid hydroxyalkyl ester, are preferred. Specifically, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, Glycerol mono (meth) acrylate, 6-hydroxyhexyl (meth) acrylate, 8-hydroxyoctyl (meth) acrylate, 10-hydroxydecyl (meth) acrylate, 12-hydroxylauryl (meth) acrylate, caprolactone-modified (meth) acrylates Polyethylene glycol (meth) acrylates, polypropylene glycol (meth) acrylates and the like.
In the hydroxyalkyl (meth) acrylate, the hydroxyl group is preferably primary, and the alkyl chain preferably has 3 to 20 carbon atoms, and more preferably 4 to 8 carbon atoms. When the number of carbon atoms in the alkyl chain of the hydroxyalkyl (meth) acrylate having a primary hydroxyl group is in the above range, crosslinking can be efficiently performed even at low functional group concentrations, and foaming at particularly high temperatures can be suppressed. In addition, it is possible to obtain a liquid crystal display device excellent in durability in which optical characteristics such as light transmittance and phase difference are not easily lowered.
Note that “2-hydroxyethyl (meth) acrylate” is an abbreviation of “2-hydroxyethyl acrylate” and “2-hydroxyethyl methacrylate”. Others are the same.

  As the monomer (b) having a carboxyl group and an ethylenically unsaturated double bond, acrylic acid, methacrylic acid, β-carboxyethyl acrylate, itaconic acid, maleic acid, maleic anhydride, crotonic acid, fumaric acid, anhydrous And fumaric acid.

Examples of the other monomer (c) having an ethylenically unsaturated double bond copolymerizable with the above (a) and (b) include the following (c1) to (c2).
(C1): A monomer having a substituent other than a hydroxyl group or a carboxyl group and an ethylenically unsaturated double bond.
(C2): Other monomer having an ethylenically unsaturated double bond that is not classified as any of the above monomers.
Monomers (c1) and (c2) are optional components.

(C1): As a monomer having a substituent other than a hydroxyl group or a carboxyl group and an ethylenically unsaturated double bond, selected from the group consisting of an amino group, an amide group, a maleimide group, an itaconimide group, a nucleenimide group, and an epoxy group And a monomer having at least one substituent and an ethylenically unsaturated double bond.

  As the monomer (c1) having an amino group and an ethylenically unsaturated double bond, aminomethyl (meth) acrylate, dimethylaminomethyl (meth) acrylate, dimethylaminoethyl (meth) acrylate, dimethylaminopropyl (meth) An acrylate etc. are mentioned.

  Examples of the monomer (c1) having an amide group and an ethylenically unsaturated double bond include (meth) acrylamide, N-substituted (meth) acrylamide, and N-vinylpyrrolidone.

  Examples of the monomer (c1) having a maleimide group and an ethylenically unsaturated double bond include N-cyclohexylmaleimide, N-isopropylmaleimide, N-laurylmaleimide, N-phenylmaleimide and the like.

  As the monomer (c1) having an itacimide group and an ethylenically unsaturated double bond, N-methylitaconimide, N-ethylitaconimide, N-butylitaconimide, N-octylitaconimide, N-2-ethylhexyl Itaconimide, N-cyclohexyl leuconconimide, N-lauryl itaconimide and the like can be mentioned.

  As the monomer (c1) having a succinimide group and an ethylenically unsaturated double bond, N- (meth) acryloyloxymethylenesuccinimide, N- (meth) acryloyl-6-oxyhexamethylenesuccinimide, N- (meth) Examples include acryloyl-8-oxyoctamethylene succinimide.

  Examples of the monomer (c1) having an epoxy group and an ethylenically unsaturated double bond include glycidyl (meth) acrylate.

Other monomers (c2) having an ethylenically unsaturated double bond not classified as any of the above monomers include vinyl monomers such as styrene, methylstyrene, vinyltoluene, vinyl acetate,
Divinyl monomers such as divinylbenzene,
1,4-butyl diacrylate, 1,6-hexyl diacrylate, hexanediol di (meth) acrylate, (poly) ethylene glycol di (meth) acrylate, (poly) propylene glycol di (meth) acrylate, neopentyl glycol di Examples thereof include diacrylate monomers such as (meth) acrylate and pentaerythritol di (meth) acrylate, and phosphate group-containing monomers such as 2-hydroxyethylacryloyl phosphate.
Among them, it is preferable to use a polyfunctional monomer such as a divinyl monomer or a diacrylate monomer because the durability (heat resistance, moist heat resistance) of the pressure-sensitive adhesive layer formed is improved. However, if a polyfunctional monomer is used in obtaining the copolymer (C), gelation tends to occur, and therefore it is preferable to use a small amount. Specifically, when the total of the monomers (a), (b), and (c) used for forming the copolymer (C) is 100% by weight, it is in the range of 0.001 to 3% by weight. Is preferred.

The smaller the alkyl methacrylate (a1) having no substituent constituting the copolymer (C), the greater the translation, vibration, and rotation of the main chain, and the more flexible pressure-sensitive adhesive layer is formed. Follows moderately without resisting dimensional changes too much. Therefore, it is suitable when a severer requirement is imposed on light leakage than durability, such as a display with a larger area.
On the other hand, the more the alkyl methacrylate (a1) having no substituent is, the more the translation, vibration, and rotation of the main chain are suppressed, and the heat resistance of the pressure-sensitive adhesive layer is improved. Therefore, it is suitable for a case where high heat resistance is required as in a vehicle-mounted display.

  Moreover, it is important that Tg of a copolymer (C) is -60-0 degreeC. When Tg is lower than −60 ° C., the pressure-sensitive adhesive layer is liable to float, peel off, foam and the like at high temperature and high temperature and high humidity.

  Moreover, a copolymer (C) needs to have a hydroxyl group and / or a carboxyl group as a functional group for reacting with the isocyanate type hardening | curing agent (D) mentioned later. The amount of the monomer (b) having a hydroxyl group and / or a carboxyl group and an ethylenically unsaturated double bond used for introducing a hydroxyl group or a carboxyl group is a single amount constituting the copolymer (C). It is preferably 0.01 to 10% by weight and more preferably 0.05 to 8% by weight in the total 100% by weight of the body. When the monomer (b) having a hydroxyl group and / or a carboxyl group and an ethylenically unsaturated double bond is less than 0.01% by weight, the cohesive force as a pressure-sensitive adhesive layer is insufficient, The pressure-sensitive adhesive film tends to float, peel off, foam and the like under high temperature and high humidity. On the other hand, if it exceeds 10% by weight, the degree of crosslinking becomes too high and the pressure-sensitive adhesiveness becomes poor.

The copolymer (C) used in the present invention contains two copolymer components, a high molecular weight component (A) and a low molecular weight component (B) as described above. These two copolymer components are classified into the following three types according to the peak shape of the GPC discharge curve.
That is, when the <2-1> copolymer (C) has a completely independent peak on the GPC discharge curve, the high molecular weight component (A1) on the high molecular weight side and the low molecular weight component on the low molecular weight side. (B1).
When the <2-2> copolymer (C) has a continuous peak on the GPC emission curve and has a minimum value, specifically a minimum value between about 20,000 and 200,000 in molecular weight The copolymer (C) contains a high molecular weight component (A2) on the high molecular weight side and a low molecular weight component (B2) on the low molecular weight side with the minimum value as a boundary.
When the <2-3> copolymer (C) does not have a clear minimum value between about 20,000 and 200,000 in the GPC emission curve, the molecular weight is 150,000 or more at the boundary of the molecular weight of 150,000. A copolymer composed of polymer molecules is used as a high molecular weight component (A3), and a copolymer component composed of polymer molecules having a molecular weight of less than 150,000 is used as a low molecular weight component (B3), and contains (A3) and (B3). .

The weight average molecular weights of the high molecular weight components (A1), (A2), and (A3) specified as described above are 500,000 to 2,200,000, and preferably 700,000 to 2,000,000. The weight average molecular weights of the low molecular weight components (B1), (B2), and (B3) specified as described above are 1,000 to 100,000, preferably 5,000 to 80,000.
If the weight average molecular weight of the high molecular weight component (A) is less than 500,000, the cohesive force of the pressure-sensitive adhesive layer will be insufficient even when reacted with the isocyanate-based curing agent (D) described later, causing floating / peeling, foaming, etc. Arise. On the other hand, a pressure-sensitive adhesive containing a high molecular weight copolymer having a high molecular weight component (A) having a weight average molecular weight greater than 2.2 million has a high viscosity and poor workability such as coating, and cannot maintain optical properties. .
In addition, when the low molecular weight component (B) having a weight average molecular weight of less than 1000 is used, the cohesive force is insufficient, and floating, peeling, foaming and the like are likely to occur. Moreover, when the low molecular weight component (B) having a weight average molecular weight exceeding 100,000 is used, the stress concentration resulting from the expansion and contraction of the film cannot be sufficiently absorbed and relaxed, and a light leakage phenomenon occurs.

Furthermore, the area ratio of peaks in GPC of the high molecular weight components (A1), (A2), (A3) and the low molecular weight components (B1), (B2), (B3) is (A1) / (B1) = 60. / 40 to 90/10, or (A2) / (B2) = 60/40 to 90/10, or (A3) / (B3) = 60/40 to 90/10. It is important that each is preferably 65/35 to 85/15.
If the proportion of the low molecular weight component (B) is too small, the stress concentration resulting from the expansion and contraction of the optical film cannot be sufficiently absorbed and relaxed, and a light leakage phenomenon occurs. On the other hand, when the proportion of the low molecular weight component (B) is too large, the cohesive force of the pressure-sensitive adhesive layer is insufficient, and it tends to float, peel off, foam and the like.
Furthermore, since the high molecular weight component (A) and the low molecular weight component (B) are contained at a ratio of 60/40 to 90/10, the adhesive layer has good reworkability even after being placed under severe conditions. Can be obtained.

Such a copolymer (C) can be obtained by various methods. For example, the high molecular weight component (A) and the low molecular weight component (B) can be obtained separately and mixed together, or after the high molecular weight component is obtained, the presence of the high molecular weight component A monomer is polymerized below to obtain a low molecular weight component (B), and a copolymer (C) can be obtained as a composition containing both.
The latter method is more preferable from the viewpoint of maintaining optical characteristics at high temperature or high temperature and high humidity.

Hereinafter, a more preferable method, that is, a method of obtaining a low molecular weight component (B) by polymerizing a monomer in the presence of the high molecular weight component after obtaining the high molecular weight component will be described in more detail.
For example, the high molecular weight component is 0.01 to 1 part by weight of the polymerization initiator, more preferably, 0.1 parts by weight with respect to a total of 100 parts by weight of the monomers (a) to (c) used in the first stage. It is obtained by a method such as bulk polymerization or solution polymerization, preferably solution polymerization, using a polymerization initiator of 01 to 0.1.

As the polymerization initiator, an azo compound or an organic peroxide is used, and two or more polymerization initiators may be used in combination.
In the case of solution polymerization, polymerization solvents include methyl acetate, ethyl acetate, n-butyl acetate, isobutyl acetate, toluene, xylene, hexane, acetone, methyl ethyl ketone, methyl isobutyl ketone, methanol, ethanol, n-propanol, isopropanol, etc. Is used. Two or more kinds of polymerization solvents may be mixed and used.

Among the polymerization initiators, examples of the azo compound include 2,2′-azobisisobutyronitrile, 2,2′-azobis (2-methylbutyronitrile), 1,1′-azobis (cyclohexane 1- Carbonitrile), 2,2′-azobis (2,4-dimethylvaleronitrile)
2,2′-azobis (2,4-dimethyl-4-methoxyvaleronitrile), dimethyl 2
, 2′-azobis (2-methylpropionate), 4,4′-azobis (4-cyanovaleric acid), 2,2′-azobis (2-hydroxymethylpropionitrile), 2,2′- And azobis [2- (2-imidazolin-2-yl) propane].

  Examples of organic peroxides include benzoyl peroxide, t-butyl perbenzoate, cumene hydroperoxide, diisopropyl peroxydicarbonate, di-n-propyl peroxydicarbonate, and di (2-ethoxyethyl) peroxy. Examples include dicarbonate, t-butyl peroxyneodecanoate, t-butyl peroxybivalate, (3,5,5-trimethylhexanoyl) peroxide, dipropionyl peroxide, diacetyl peroxide and the like.

First, it is preferable to polymerize the monomers (a) to (c) until the polymerization conversion becomes 60 to 90% by controlling the blending amount of the polymerization initiator as described above. A copolymer constituting the high molecular weight component (A) of the copolymer (C) can be obtained in the system by the step polymerization. The copolymer obtained by the first stage polymerization mainly comprises the high molecular weight component (A), but may contain other copolymerization components.
Here, the polymerization conversion rate is a value obtained by dividing the weight of the copolymer obtained by polymerizing the monomer by the total weight of the monomers used as raw materials. More specifically, a very small amount of the solution during polymerization is sampled and heated at 150 ° C. for about 20 minutes to obtain the solid content. The monomer volatilizes under the heating conditions, but the copolymer does not volatilize. Therefore, by obtaining the solid content of the solution, the amount of the copolymer contained can be obtained, and the polymerization conversion rate is calculated based on that.

Then, if necessary, new monomers (a) to (c) and / or a polymerization initiator are added, and as a second stage polymerization, monomers remaining in the system after the first stage polymerization (and A new monomer added as necessary) is further radically polymerized to form the low molecular weight component (B). Thereby, the copolymer (C) containing a high molecular weight component (A) and a low molecular weight component (B) can be obtained.
The polymerization conversion rate of the copolymer (C) in the second stage polymerization is preferably 80 to 100%, more preferably 90 to 100%, and further preferably 95 to 100%. That is, the monomer remaining in the reaction system is preferably 20% of the total 100% by weight of the monomers used in the polymerization, including the monomer added as necessary in the second stage polymerization step. To obtain a copolymer (C) by radical copolymerization to form a low molecular weight component until it is less than 10%, more preferably less than 10% by weight, and even more preferably less than 5% by weight. Can do.

  In this second stage polymerization, it is preferable to add a new monomer, and in particular, a monomer (b) having a hydroxyl group and / or a carboxyl group and an ethylenically unsaturated double bond may be added. More preferred. As described above, the monomer (b) is 0.01 to 10% by weight in the total 100% by weight of all monomers used for the polymerization of the high molecular weight component (A) and the low molecular weight component (B). It is preferable that it is 0.05 to 8% by weight. Among these, the amount of the monomer (b) used in the first stage polymerization is preferably 0.008 to 8% by weight, and more preferably 0.04 to 6% by weight. The amount of the monomer (c1) newly added during the second stage polymerization is preferably 0.002 to 2% by weight, more preferably 0.01 to 2% by weight. . The addition of the monomer (b) and the introduction of a hydroxyl group and / or a carboxyl group into the low molecular weight component (B) positively allows the pressure-sensitive adhesive from the end when the optical film is cut. Effective for preventing protrusion.

When the low molecular weight component (B) is formed in the second stage polymerization, the polymerization initiator used in the first stage is more than the polymerization initiator used in the first stage. It is preferable to use about 50 times the weight of the polymerization initiator. More specifically, 0.05 to 50 parts by weight of a polymerization initiator, more preferably 0.05 to 100 parts by weight of the total of the monomers (a) to (c) used in the second stage. It is preferred to use -5 parts by weight of a polymerization initiator.
Furthermore, in order to control the molecular weight to the low molecular weight side, during the synthesis of the low molecular weight component (B), mercaptans such as n-lauryl mercaptan and n-dodecyl mercaptan, chain transfer agents such as α-methylstyrene dimer and limonene are added. May be used.
Thus, in GPC, a copolymer (C) is obtained in which the area ratio of the high molecular weight component (A) to the low molecular weight component (B) is (A) / (B) = 60/40 to 90/10. be able to.

The pressure-sensitive adhesive of the present invention is obtained by mixing the above-mentioned copolymer (C) having a hydroxyl group and / or a carboxyl group and a compound (D) having a functional group capable of reacting with a hydroxyl group or a carboxyl group. be able to. Upon mixing, the copolymer (C) is preferably in a solution state dissolved in an organic solvent.
The compound (D) having a functional group capable of reacting with a hydroxyl group or a carboxyl group reacts with the copolymer (C) having a hydroxyl group and / or a carboxyl group to obtain a pressure-sensitive adhesive layer when a pressure-sensitive adhesive film is obtained. Form. Examples of the compound (D) having a functional group capable of reacting with a hydroxyl group or a carboxyl group include an isocyanate compound, an epoxy compound, an amine compound, a metal chelate compound, and an aziridine compound. In particular, isocyanate compounds are preferred, and the polyfunctional compounds can be used alone or in combination.

  Examples of isocyanate compounds are bifunctional, such as tolylene diisocyanate, chlorophenylene diisocyanate, hexamethylene diisocyanate, tetramethylene diisocyanate, isophorone diisocyanate, xylylene diisocyanate, diphenylmethane diisocyanate, hydrogenated diphenylmethane diisocyanate. Isocyanate monomers, and so-called adducts obtained by modifying these bifunctional isocyanate monomers with trifunctional polyols such as trimethylolpropane, and trimers having isocyanurate rings formed from three molecules of bifunctional isocyanate monomers (isocyanurate bodies) ) A burette type compound which is a reaction product of 3 mol of a bifunctional isocyanate monomer and water, as well as a polyether polyol or a polyol. Ester polyols, acryl polyols, polybutadiene polyols, polyisoprene polyols urethane prepolymer type obtained by addition reaction, such as isocyanate and the like. These isocyanate curing agents (D) are preferably used in an amount of 0.01 to 15 parts by weight with respect to 100 parts by weight of the copolymer (C). If it is less than 0.01 part by weight, the cohesive force of the pressure-sensitive adhesive layer tends to decrease, and if it exceeds 15 parts by weight, the pressure-sensitive adhesiveness to the adherend becomes poor. More preferably, it is 0.03-10 weight part, and 0.03-2 weight part is especially preferable.

These isocyanate compounds can be used alone or in combination of two or more. In the case of using in an application in which flexibility is important, it is preferable to use a trifunctional isocyanate compound.
Examples of epoxy compounds include bisphenol A-epichlorohydrin type epoxy resins, ethylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, glycerin diglycidyl ether, glycerin triglycidyl ether, 1,6-hexane. Diol diglycidyl ether, trimethylolpropane triglycidyl ether, diglycidyl aniline, N, N, N ′, N′-tetraglycidyl-m-xylylenediamine, 1,3-bis (N, N′-diglycidylaminomethyl) ) Cyclohexane, N, N, N ′, N′-tetraglycidylaminophenylmethane, triglycidyl and the like.
Examples of the aziridine compound include N, N′-diphenylmethane-4,4′-bis (
1-aziridinecarboxite), N, N′-toluene-2,4-bis (1-aziridinecarboxite), bisisophthaloyl-1- (2-methylaziridine), tri-1-aziridinylphosphine oxide N, N′-hexamethylene-1,6-bis (1-aziridinecarboxite), trimethylolpropane tri-β-aziridinylpropionate, tetramethylolmethanetri-β-aziridinylpropionate, Tris-2, 4,
Examples include 6- (1-aziridinyl) -1,3,5-triazine.

  Examples of metal chelate curing agents include coordination compounds of polyvalent metals such as aluminum, iron, copper, zinc, tin, titanium, nickel, antimony, magnesium, vanadium, chromium and zirconium with acetylacetone and ethyl acetoacetate. Etc.

  Furthermore, examples of the amine curing agent include hexamethylenediamine, triethyldiamine, polyethyleneimine, hexamethylenetetramine, diethylenetriamine, triethyltetramine, isophoronediamine, amino resin, and methylene resin.

Next, the antistatic agent (E) used in the present invention will be described.
The antistatic imparting agent (E) used in the present invention is a boron-based antistatic agent, and is an ammonium salt compound (E1) represented by the following general formula [1], or the following general formula [2]. This is a represented alkali metal salt compound (E2).

(In General Formula (1) and General Formula (2), R ¹ to R ⁸ are each independently a hydrogen atom, an alkyl group that may have a substituent, an alkenyl group that may have a substituent, An alkynyl group that may have a substituent, an aryl group that may have a substituent, or a heterocyclic group that may have a substituent, wherein R ⁵ to R ⁸ are adjacent to each other You may form a ring with
In the general formula (2), A ⁺ represents an alkali metal ion. )

In the ammonium salt compound (E1), the cation part is N ⁺ R ⁵ R ⁶ R ⁷ R ⁸ , and all the constituent parts including the anion part are organic, so that the copolymer (C) or solvent It is characterized by high compatibility. Further, when the ammonium salt compound (E1) is used, the antistatic performance is hardly affected by the environmental humidity.
Further, the compound (E2) has a feature that since the cation portion is an alkali metal ion, the production process can be shortened and can be produced at low cost.
However, when an alkali metal salt compound (E2) is used, there is a possibility that electronic components such as internal circuits, transistors, ICs, and CPUs may be contaminated. The Further, when the alkali metal salt compound (E2) is used, if the adherend is aluminum or the like, the floating is likely to occur in a high-temperature and high-humidity environment. Furthermore, when an alkali metal salt compound (E2) is used, the antistatic performance is easily affected by environmental humidity.
Therefore, in this invention, it is preferable to use the ammonium salt type compound (E1) represented by General formula [1] as an antistatic provision agent (E).

  As the alkyl group which may have a substituent, an alkyl group having 1 to 30 carbon atoms is preferable, for example, methyl group, ethyl group, propyl group, butyl group, hexyl group, octyl group, decyl group, dodecyl group, Okudadecyl group, isopropyl group, isobutyl group, sec-butyl group, tert-butyl group, 1-ethylpentyl group, cyclopentyl group, cyclohexyl group, trifluoromethyl group, 2-ethylhexyl group, phenacyl group, 1-naphthoylmethyl group 2-naphthoylmethyl group, 4-methylsulfanylphenacyl group, 4-phenylsulfanylphenacyl group, 4-dimethylaminophenacyl group, 4-cyanophenacyl group 4-methylphenacyl group, 2-methylphenacyl group, 3-fluorophenacyl group, 3-trifluoromethylphenacyl group, 3-nitrophena Examples include a syl group.

  As an alkenyl group which may have a substituent, a C2-C10 alkenyl group is preferable, for example, a vinyl group, an allyl group, a styryl group etc. are mentioned.

  The alkynyl group which may have a substituent is preferably an alkynyl group having 2 to 10 carbon atoms, and examples thereof include an ethynyl group, a propynyl group, and a propargyl group.

  As the aryl group which may have a substituent, an aryl group having 6 to 30 carbon atoms is preferable, and a phenyl group, a biphenyl group, a 1-naphthyl group, a 2-naphthyl group, a 9-anthryl group, a 9-phenanthryl group, 1-pyrenyl group, 5-naphthacenyl group, 1-indenyl group, 2-azurenyl group, 9-fluorenyl group, terphenyl group, quarterphenyl group, o-, m-, and p-tolyl group, xylyl group, o- , M-, and p-cumenyl group, mesityl group, pentarenyl group, binaphthalenyl group, turnaphthalenyl group, quarternaphthalenyl group, heptaenyl group, biphenylenyl group, indacenyl group, fluoranthenyl group, acenaphthylenyl group, aceanthrylenyl group, Phenalenyl group, fluorenyl group, anthryl group, bianthracenyl group, teranthra Nyl group, quarter anthracenyl group, anthraquinolyl group, phenanthryl group, triphenylenyl group, pyrenyl group, chrysenyl group, naphthacenyl group, preadenyl group, picenyl group, perylenyl group, pentaphenyl group, pentacenyl group, tetraphenylenyl group, Examples include a hexaphenyl group, a hexacenyl group, a rubicenyl group, a coronenyl group, a trinaphthylenyl group, a heptaphenyl group, a heptacenyl group, a pyranthrenyl group, and an ovalenyl group.

  The heterocyclic group that may have a substituent is preferably an aromatic or aliphatic heterocyclic ring containing a nitrogen atom, an oxygen atom, a sulfur atom, or a phosphorus atom. For example, thienyl group, benzo [b] thienyl group, naphtho [2,3-b] thienyl group, thiantenyl group, furyl group, pyranyl group, isobenzofuranyl group, chromenyl group, xanthenyl group, phenoxathinyl group, 2H-pyrrolyl group, pyrrolyl group, imidazolyl group, pyrazolyl group, pyridyl group, pyrazinyl group, pyrimidinyl group, pyridazinyl group, indolizinyl group, isoindolyl group, 3H-indolyl group, indolyl group, 1H-indazolyl group, purinyl group, 4H- Quinolidinyl group, isoquinolyl group, quinolyl group, phthalazinyl group, naphthyridinyl group, quinoxanilyl group, quinazolinyl group, cinnolinyl group, pteridinyl group, 4aH-carbazolyl group, carbazolyl group, β-carbolinyl group, phenanthridinyl group, acridinyl group Group, phenanthrolinyl group, phenazinyl group, phenalsadinyl group, isothiazolyl group, phenothiazinyl group, isoxazolyl group, furazanyl group, phenoxazinyl group, isochromanyl group, chromanyl group, pyrrolidinyl group, pyrrolinyl group, imidazolidinyl group, imidazolinyl group, pyrazolidinyl group Group, pyrazolinyl group, piperidyl group, piperazinyl group, indolinyl group, isoindolinyl group, quinuclidinyl group, morpholinyl group, thioxanthryl group and the like.

  Furthermore, the alkyl group which may have a substituent mentioned above, the alkenyl group which may have a substituent, the alkynyl group which may have a substituent, the aryl group and the substituent which may have a substituent The hydrogen atom of the heterocyclic group which may have may be further substituted with another substituent.

  Examples of such substituents include halogen groups such as fluorine atom, chlorine atom, bromine atom and iodine atom, alkoxy groups such as methoxy group, ethoxy group and tert-butoxy group, aryl groups such as phenoxy group and p-tolyloxy group. Oxy group, methoxycarbonyl group, butoxycarbonyl group, phenoxycarbonyl group, vinyloxycarbonyl group, alkoxycarbonyl group such as aryloxycarbonyl group, acetoxy group, propionyloxy group, acyloxy group such as benzoyloxy group, acetyl group, benzoyl group An arylsulfuric group such as an acyl group such as an isobutyryl group, an acryloyl group, a methacryloyl group or a methoxalyl group, an alkylsulfanyl group such as a methylsulfanyl group or a tert-butylsulfanyl group, a phenylsulfanyl group or a p-tolylsulfanyl group Nyl group, alkylamino group such as methylamino group, cyclohexylamino group, dimethylamino group, diethylamino group, morpholino group, dialkylamino group such as piperidino group, arylamino group such as phenylamino group, p-tolylamino group, methyl group Alkyl group such as ethyl group, tert-butyl group, dodecyl group, phenyl group, p-tolyl group, xylyl group, cumenyl group, naphthyl group, anthryl group, phenanthryl group and other aryl groups, hydroxyl group, carboxyl Group, sulfonamido group, formyl group, mercapto group, sulfo group, mesyl group, p-toluenesulfonyl group, amino group, nitro group, nitroso group, cyano group, trifluoromethyl group, trichloromethyl group, trimethylsilyl group, phosphinico group , Phosphono group, alkylsulfonyl group, aryl Examples include a sulfonyl group, a trialkylammonium group, a dimethylsulfonyl group, and a triphenylphenacylphosphoniumyl group.

  Among such substituents, a preferred substituent is an electron-withdrawing substituent. When the electron-withdrawing substituent is substituted, the ionic compound is generally easily dissociated and the antistatic ability is enhanced.

  Such electron-attracting substituents are generic names for substituents that attract electrons from the other party due to resonance effects and induced effects, and many of them have a positive substituent constant σ on the Hammett side. It is. These substituents are not particularly limited, and specific examples thereof include Chemical Review Vol. 91, Nos. 165 to 195 σp described in 1991 is greater than 0, and more specifically, halogen group, cyano group, carboxyl group, nitro group, nitroso group, acyl group, alkyloxycarbonyl Group, aryloxycarbonyl group, alkylsulfonyl group, arylsulfonyl group, trialkylammonium group, amide group, perfluoroalkyl group, perfluoroalkylthio group, perfluoroalkylcarbonyl group, sulfonamide group, 4-cyanophenyl group and the like.

R ¹ to R ⁴ are preferably an alkyl group which may have a substituent or an aryl group which may have a substituent, more preferably a substituent, in view of the stability of the compound. It is an aryl group that may have.

R ⁵ to R ⁸ are preferably an alkyl group which may have a substituent in consideration of the stability of the compound.

  Representative examples of the boron-based ammonium salt compound (E1) represented by the general formula [1] used as the antistatic agent (E) in the present invention are exemplified compounds (E1-1) to (E1-15). ) As representative compounds of the boron-based alkali metal salt compound (E2) represented by the general formula [2] as exemplified compounds (E2-1) to (E2-4) These are specifically exemplified in Table 2 below, but are not limited thereto.

  In the exemplified compounds, Me represents a methyl group, Et represents an ethyl group, Bu represents a normal butyl group, c-Hex represents a cyclohexyl group, and Ph represents a phenyl group.

  As addition amount of antistatic agent (E), 0.001-20 weight part is preferable with respect to 100 weight part of copolymers (C), and 0.01-10 weight part is more preferable. If it is less than 0.001 part by weight, an antistatic function cannot be expected. If it exceeds 20 parts by weight, the physical properties of the adhesive may deteriorate. The antistatic agent (E) can be used alone or in combination.

It is preferable that a silane coupling agent is further added to the antistatic acrylic pressure-sensitive adhesive of the present invention.
As silane coupling agents, vinyltrimethoxysilane, vinyltriethoxysilane, methacryloxypropyltrimethoxysilane, γ-methacryloxypropylmethyldimethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropylmethyl Dimethoxysilane, γ-glycidoxypropylmethyldiethoxysilane, 2- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, γ-aminopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, γ-aminopropylmethyl Methoxysilane, N- (2-aminoethyl) 3-aminopropyltrimethoxysilane, N- (2-aminoethyl) 3-aminopropylmethyldimethoxysilane, γ-mercaptopropyltrimethoxysilane, γ-mer Hept triethoxysilane, mercaptopropyl butyl trimethoxysilane, .gamma.-mercaptopropyl methyl dimethoxy silane, and the like.
The silane coupling agent is effective in improving the adhesion between the pressure-sensitive adhesive layer and the glass, and is particularly effective in preventing the pressure-sensitive adhesive film from floating / peeling and foaming under high temperature and high humidity.

The content of the silane coupling agent in the antistatic acrylic pressure-sensitive adhesive is preferably 0.01 to 2 parts by weight with respect to 100 parts by weight of the copolymer (C). If the amount is less than 0.01 parts by weight, the effect of improving the physical properties is poor. If the amount exceeds 2 parts by weight, the pressure-sensitive adhesive is not only expensive, but also causes floating, peeling and foaming.
Moreover, you may mix | blend an ultraviolet absorber, antioxidant, a pressure sensitive adhesion imparting resin, a plasticizer, an antifoamer, a leveling regulator etc. in the pressure sensitive adhesive in the range which does not inhibit the effect of this invention.

Next, the antistatic acrylic pressure-sensitive adhesive film of the present invention will be described.
The pressure-sensitive adhesive film of the present invention has an antistatic acrylic pressure-sensitive adhesive layer comprising the antistatic acrylic pressure-sensitive adhesive of the present invention formed on at least one surface of an optical film used for various display members. It is what. The pressure-sensitive adhesive film of the present invention is suitably used for forming various display members. For example, it is suitably affixed and used on the glass of a liquid crystal display member.

  Examples of the optical film used in the present invention include a polarizing film and a retardation film, and a polarizing film is preferable.

A pressure-sensitive adhesive sheet is obtained by applying the pressure-sensitive adhesive of the present invention to the above optical film, drying to form a pressure-sensitive adhesive layer, laminating a release sheet, and aging as necessary. Can do.
Alternatively, the pressure-sensitive adhesive layer on the optical film can be formed by applying a pressure-sensitive adhesive to the release sheet, drying to form a pressure-sensitive adhesive layer, and bonding the optical film to make the pressure-sensitive adhesive layer optical. It is also possible to use a so-called “transfer method” in which the image is transferred onto a film.

  The pressure-sensitive adhesive layer can be formed using a commonly used coating apparatus. Examples of the coating apparatus include a roll knife coater, a die coater, a roll coater, a bar coater, a gravure roll coater, a reverse roll coater, dipping, and a blade coater.

  The thickness of the pressure-sensitive adhesive layer is preferably 1 to 200 μm. If it is less than 1 μm, the pressure-sensitive adhesiveness becomes poor, and if it exceeds 200 μm, it is difficult to produce and handle a pressure-sensitive adhesive film.

  EXAMPLES Next, although an Example of this invention is shown and it demonstrates still in detail, this invention is not limited by these. In the examples, “part” means “part by weight”, and “%” means “% by weight”.

  In the following production examples and comparative production examples, for convenience, a copolymer component having a weight average molecular weight of 100,000 or more is designated as “high molecular weight component (A)”, and a copolymer component having a weight average molecular weight of less than 100,000 is designated as “low and high”. The molecular weight component (B) ”was assigned a serial number. Further, the copolymer was given a serial number as “C” regardless of whether or not it was an embodiment of the present invention.

[Production Example 1]
In a reaction vessel equipped with a stirrer, a thermometer, a reflux condenser, a dropping device, and a nitrogen introduction tube, 58 parts of n-butyl acrylate, 40 parts of methyl methacrylate, 1.5 parts of acrylic acid, 100 parts of acetone, AIBN (2, 2 '-Azobisisobutyronitrile, hereinafter referred to as “AIBN”.
) 0.03 part was charged, and the air in the reaction vessel was replaced with nitrogen gas, and then the reaction solution was reacted for 4.5 hours under a nitrogen atmosphere with stirring until the conversion rate reached 75% at the reflux temperature. Thus, a mixed solution of a copolymer having a weight average molecular weight of 1,000,000 and a monomer was obtained. Next, 200 parts of toluene, 0.5 part of acrylic acid, and 0.2 part of AIBN were added, and the reaction was further continued for 6 hours until the conversion reached 100%. A solution of the copolymer (C1) having a Tg of −7 ° C. Obtained.
The copolymer (C1) does not contain a polymer having a molecular weight of less than 150,000, has a weight average molecular weight of 1,000,000, a high molecular weight component (A1-1) having a Tg of −7.4 ° C., and a molecular weight of 150,000 or more. The polymer was not contained and the low molecular weight component (B1-1) whose weight average molecular weight is 25,000 and Tg is -5.8 degreeC was contained. The high molecular weight component (A1-1) and the low molecular weight component (B1-1) show two independent peaks in the GPC discharge curve, and the area ratio of both is (A1-1) / (B1 -1) = 75/25.

In addition, Tg of the high molecular weight component (A1-1) is a glass transition temperature of a homopolymer obtained from each monomer (that is, a blended monomer) assuming that each monomer used is uniformly polymerized. Is a value obtained by the following formula (1) (FOX formula). The Tg of the low molecular weight component (B1-1) is based on the amount of each monomer remaining unreacted and each added monomer and the glass transition temperature of the homopolymer obtained from each monomer. This is a value obtained by the following equation (1) (FOX equation). The Tg of the copolymer (C1) is expressed by the following formula (1) (FOX formula) based on the glass transition temperature of the homopolymer obtained from each monomer constituting the copolymer (C1). This is the calculated value.
1 / Tg = [(W1 / Tg1) + (W2 / Tg2) +... + (Wn / Tgn)] / 100 Formula (1)
(The temperature here is absolute.)
Wn:% by weight of monomer n
Tgn: Glass transition temperature of homopolymer composed of monomer n

[Production Example 2]
In a reaction vessel, 94.5 parts of n-butyl acrylate, 3.5 parts of methyl methacrylate, 1.5 parts of 4-hydroxyl butyl acrylate, light acrylate 4EG-A (PEG # 200 diacrylate, manufactured by Kyoeisha Chemical Co., Ltd.) 02 parts, 100 parts of acetone and 0.03 part of AIBN were charged and reacted for 4.5 hours until the conversion rate reached 75% in the same manner as in Production Example 1, and a copolymer with a weight average molecular weight of 1.15 million and a single amount. A mixed solution with the body was obtained.
Next, 150 parts of ethyl acetate, 50 parts of toluene, 0.5 part of acrylic acid and 0.2 part of AIBN were added, and the reaction was further continued for 6 hours until the conversion reached 100%. A solution of coalescence (C2) was obtained.
The copolymer (C2) shows a continuous peak having a minimum value at a molecular weight of 150,000 in GPC, a high molecular weight component (A1-2) on the higher molecular weight side than this minimum value, and a lower molecular weight than the minimum value. The low molecular weight component (B1-2) on the side was used. Each component has a high molecular weight component (A1-2) having a Tg of −51.2 ° C. and a weight average molecular weight of 1,200,000, and a low molecular weight component having a Tg of −49.3 ° C. and a weight average molecular weight of 38,000 (B1). -2), and the area ratio of both was (A1-2) / (B1-2) = 75/25. In addition, Tg was calculated | required excluding "light acrylate 4EG-A" which was trace amount.

[Production Example 3]
A reaction vessel was charged with 76 parts of n-butyl acrylate, 20 parts of methyl acrylate, 3.5 parts of acrylic acid, 100 parts of acetone, and 0.1 part of AIBN. The air in the reaction container was replaced with nitrogen gas, and then stirred. Under a nitrogen atmosphere, the reaction solution was reacted at reflux temperature for 2.0 hours. Next, 10 parts of ethyl acetate was added every hour, and the reaction was further continued for 5.0 hours at the reflux temperature. Next, 50 parts of ethyl acetate, 0.1 part of AIBN and 0.5 part of acrylic acid were added, and the reaction was further continued for 2 hours until the conversion rate reached 100%. A copolymer (C3) having a Tg of −39.8 ° C. Solution was obtained. The copolymer (C3) shows a continuous peak having no clear minimum value in GPC, and a high molecular weight side (A1-3) and a low molecular weight side (B1-3) with a molecular weight of 150,000 as a boundary. did. Each component has a high molecular weight component (A1-3) having a Tg of −40.0 ° C. and a weight average molecular weight of 1,050,000, and a low molecular weight component having a Tg of −39.1 ° C. and a weight average molecular weight of low molecular weight of 35,000 (B1 -3), and the area ratio of the two was (A1-3) / (B1-3) = 80/20.

[Production Example 4]
A reaction vessel was charged with 98 parts of n-butyl acrylate, 1 part of acrylic acid, 1 part of acrylamide, 100 parts of ethyl acetate, and 0.03 part of AIBN, and the air in the reaction container was replaced with nitrogen gas, and then nitrogen was stirred. Under an atmosphere, this reaction solution is reacted at reflux temperature for 8 hours until the conversion rate reaches 100%, and does not contain a component having a weight average molecular weight of 700,000 and a molecular weight of less than 100,000, and has a high Tg of −52.3 ° C. A solution of the molecular weight copolymer (A1-4) was obtained, diluted with ethyl acetate, and the non-volatile content concentration was adjusted to 25%.

  In a separate reaction vessel, 86,4 parts of n-butyl acrylate, 13.6 parts of methyl methacrylate, 200 parts of ethyl acetate, and 0.03 part of AIBN were charged, and the air in the reaction container was replaced with nitrogen gas, followed by stirring. Under a nitrogen atmosphere, this reaction solution was reacted at reflux temperature for 4 hours until the conversion rate reached 100%, and the Tg was −40.7 ° C., the weight average molecular weight was 300,000, A solution of molecular weight copolymer (B1-4) was obtained. The obtained copolymer solution was diluted with ethyl acetate to adjust the nonvolatile content concentration to 25%.

  Next, both copolymer solutions were prepared so that the weight ratio of the high molecular weight component (A1-4) to the low molecular weight component (B1-4) was (A1-4) / (B1-4) = 100/30. By mixing, a copolymer (C4) solution having a Tg of −49.7 ° C. was obtained. In the alkyl methacrylate having no substituent constituting the copolymer (C4), (a1) was about 3.1%. The copolymer (C4) shows a continuous peak having no clear minimum value in GPC, and the area ratio between the high molecular weight side and the low molecular weight side with a molecular weight of 150,000 is 83/17, The weight average molecular weight on the high molecular weight side was 550,000, and the weight average molecular weight on the low molecular weight side was 80,000.

[Production Example 5]
The same as in Production Example 4 except that the monomer composition was 95 parts of n-butyl acrylate and 5 parts of acrylic acid, and 100 parts of acetone and 0.2 parts of AIBN were used instead of 100 parts of ethyl acetate and 0.03 parts of AIBN. The polymer is allowed to react for 10 hours until the conversion rate reaches 100%, the high-molecular weight copolymer (A1-Tg is −49.3 ° C., the weight average molecular weight is 1,500,000 and does not contain a component having a molecular weight of less than 150,000. 5) A solution was obtained, diluted with ethyl acetate, and the nonvolatile content concentration was adjusted to 20%.

  Separately, the monomer composition is 99 parts of n-butyl acrylate and 1 part of acrylic acid. Instead of 150 parts of toluene and 0.03 part of AIBN, 100 parts of toluene, 5 parts of α-methylstyrene dimer as a chain transfer agent, AIBN2 In the same manner as in Production Example 4 except that the components are used, the reaction is allowed to proceed for 6 hours until the conversion rate reaches 100%, and the Tg is -53 ° C., the weight average molecular weight is 8000, and the molecular weight is 150,000 or more A low molecular weight copolymer (B1-5) solution was obtained and diluted with toluene to adjust the nonvolatile content concentration to 40%.

Next, both the high molecular weight copolymer (A1-5) and the low molecular weight copolymer (B1-5) were mixed so that the weight ratio was (A1-5) / (B1-5) = 60/40. The polymer solution was mixed to obtain a copolymer (C5) solution having a Tg of −50.7 ° C.
The alkyl methacrylate having no substituent constituting the copolymer (C5) was 0%. Moreover, when GPC was measured about the said copolymer (C5), it had two independent peaks, and the area ratio of a high molecular weight copolymer (A1-5) and a low molecular weight copolymer (B1-5) Was (A1-5) / (B1-5) = 60/40.

[Production Example 6]
The monomer composition is 96 parts of n-butyl acrylate, 4 parts of acrylic acid, 80 parts of ethyl acetate, 20 parts of acetone and 0.03 part of AIBN, and in the same manner as in Production Example 4, until the conversion becomes 100%. React for 8 hours to obtain a high molecular weight copolymer (A1-6) solution having a Tg of −50.2 ° C., a weight average molecular weight of 900,000 and containing no components with a molecular weight of less than 150,000, diluted with ethyl acetate Then, the nonvolatile content concentration was adjusted to 20%.

  Separately, the monomer composition was 84 parts of n-butyl acrylate, 15 parts of n-butyl methacrylate, 1 part of acrylic acid, and 200 parts of ethyl acetate and 0.05 parts of AIBN were used. A low molecular weight copolymer (A1-6) solution containing components having a Tg of -41.9 ° C., a weight average molecular weight of 250,000, and a molecular weight of 50,000 or more, until the conversion reaches 100%. And diluted with toluene to adjust the nonvolatile content concentration to 20%.

    Next, both copolymer solutions were prepared so that the weight ratio of the high molecular weight component (A1-6) to the low molecular weight component (B1-6) was (A1-6) / (B1-6) = 100/30. By mixing, a copolymer (C6) solution having a Tg of −48.2 ° C. was obtained. In the alkyl methacrylate having no substituent constituting the copolymer (C6), (a1) was about 3.5%. The copolymer (C6) shows a continuous peak having a minimum value at a molecular weight of 200,000 in GPC, the high molecular weight component (A1-6) on the high molecular weight side from this minimum value, and the minimum value. A low molecular weight component (B1-6) on the low molecular weight side, the weight average molecular weight of the high molecular weight component (A1-6) is 760,000, and the weight average molecular weight of the low molecular weight component (B1-6) is 91,000. The area ratio of the two was (A1-6) / (B1-6) = 83/17.

[Comparative Production Example 1]
The weight ratio of the high molecular weight copolymer (A1-5) obtained in Production Example 5 to the low molecular weight copolymer (B1-5) is (A1-5) / (B1-5) = 40/60. Thus, both copolymer solutions were mixed to obtain a copolymer (C7) solution having a Tg of −51.5 ° C.
The alkyl methacrylate having no substituent constituting the copolymer (C7) was 0%. Moreover, when GPC was measured about the said copolymer (C7), it had two independent peaks, and the area ratio of a high molecular weight copolymer (A1-5) and a low molecular weight copolymer (B1-5) Was (A1-5) / (B1-5) = 40/60.

Abbreviations of monomers in Table 3 are shown below.
BA: butyl acrylate MMA: methyl methacrylate AA: acrylic acid AAm: acrylamide

In addition, the weight average molecular weight of a copolymer is the weight average molecular weight of polystyrene conversion calculated | required by GPC measurement, and GPC measurement conditions are as follows.
Apparatus: Shodex GPC System-21 [manufactured by Showa Denko KK]
Column: A total of three Shodex KF-602.5 and two Shodex KF-606M (manufactured by Showa Denko KK) are connected and used.
Solvent: Tetrahydrofuran Flow rate: 0.5 ml / min
Temperature: 40 ° C
Sample concentration: 0.1 wt%
Sample injection volume: 50 μl

<Manufacture of boron antistatic agent (E)>
<Production Example 7> Synthesis of ammonium salt compound (E1-1) 342 g of sodium tetraphenylborate was dissolved in 5 L of ion-exchanged water. To this, 322 g of tetrabutylammonium bromide dissolved in 5 L of ion exchange water was gradually added. After stirring for 5 hours, the precipitate was collected by filtration to obtain 373 g of a compound (E1-1) represented by the following formula. Elemental analysis (Composition formula: C ₄₀ H ₅₆ BN Calculated value (%): C, 85.53; H, 10.05; N, 2.49 Actual value (%): C, 85.55; H, 10. 52; N, 2.66).

<Production Examples 8 to 20> Synthesis of Compounds (6) to (18) Production was performed except that the borate shown in Table 4 was used instead of sodium tetraphenylborate and the ammonium salt shown in Table 6 was used instead of tetrabutylammonium bromide. In the same manner as in Example 3, compound (E1-15) was synthesized from compound (E1-2) and compound (E1-4). Table 5 shows the results of elemental analysis.

[Example 1]
With respect to 100 parts of the solid content of the copolymer (C1) solution obtained in Production Example 1, 0.2 part of an isocyanate curing agent (trimethylolpropane adduct of tolylene diisocyanate) as an active ingredient, compound (E1 1.0 parts of -1) and 0.1 part of silane coupling agent 1 (3-glycidoxypropyltrimethoxysilane) as active ingredients were added and stirred well to obtain an adhesive composition. The obtained adhesive composition was subjected to various tests described later.

[Example 2]
0.05 part of an isocyanate curing agent (trimethylolpropane adduct of tolylene diisocyanate) as an active ingredient with respect to 100 parts of the copolymer (C2) solution obtained in Production Example 2, Compound (E1-1) 1.0 part of silane coupling agent 1 (3-glycidoxypropyltrimethoxysilane) as an active ingredient was added and stirred well to obtain an adhesive composition. The obtained adhesive composition was tested in the same manner as in Example 1.

[Example 3], [Example 5]
An isocyanate curing agent (trimethylolpropane adduct of tolylene diisocyanate) is added as an active ingredient to 100 parts of each of the solutions (C3) and (C5) obtained in Production Example 3 and Production Example 5. 3 parts, 1.0 part of compound (E1-1) and 0.1 part of silane coupling agent 1 (3-glycidoxypropyltrimethoxysilane) as an active ingredient are added and stirred well to obtain an adhesive composition. Obtained. The obtained adhesive composition was tested in the same manner as in Example 1.

[Example 4]
With respect to 130 parts of the copolymer (C4) solution obtained in Production Example 4, an epoxy-based curing agent (N, N, N ′, N′-tetraglycidyl-m-xylenediamine) is 0.6 as an active ingredient. Part, 1.0 part of compound (E1-1) and 0.1 part of silane coupling agent 1 (3-glycidoxypropyltrimethoxysilane) as active ingredients were added and stirred well to obtain an adhesive composition It was. The obtained adhesive composition was tested in the same manner as in Example 1.

[Example 6]
0.25 parts of an isocyanate curing agent (trimethylolpropane adduct of tolylene diisocyanate) as an active ingredient with respect to 130 parts of the copolymer (C6) solution obtained in Production Example 5, compound (E1-1) 1.0 part of silane coupling agent 1 (3-glycidoxypropyltrimethoxysilane) as an active ingredient was added and stirred well to obtain an adhesive composition. The obtained adhesive composition was tested in the same manner as in Example 1.

[Comparative Example 1]
For 100 parts of the copolymer (C7) liquid obtained in Comparative Production Example 1, 0.2 part of an isocyanate curing agent (trimethylolpropane adduct of tolylene diisocyanate) as an active ingredient, compound (E1-1) ) And 0.1 part of silane coupling agent 1 (3-glycidoxypropyltrimethoxysilane) as an active ingredient were added and stirred well to obtain an adhesive composition. The obtained adhesive composition was tested in the same manner as in Example 1.

[Example 7] to [Example 20]
Instead of compound (E1-1), compound (E1-4) to compound (E1-15) and compounds (E2-1) and (E2-4) were used in the same manner as in Example 1, except that each was used. Thus, an adhesive composition was obtained and evaluated in the same manner as in Example 1.

[Various tests]
<Base material adhesion and reworkability>
The adhesive composition obtained in each Example and each Comparative Example was applied to a polyester release film (thickness 38 μm) and dried at 100 ° C. for 2 minutes to form an adhesive layer having a thickness of 25 μm. A polarizing film (thickness: 180 μm) was bonded to the adhesive layer, and left for 7 days in an atmosphere of 23 ° C.-50% RH to advance the reaction (aging), whereby an adhesive film 1 was obtained.
The obtained pressure-sensitive adhesive film 1 is cut to a width of 25 mm, the release film is peeled off, and the exposed pressure-sensitive adhesive layer is attached to a glass plate having a thickness of 0.7 mm at 23 ° C.-50% RH, in accordance with JIS Z 0237. Roll-bonded.
After 24 hours of pressure bonding, after standing at 60 ° C. for 500 hours, the polarizing film was peeled from the glass plate at a peel tester in a 23 ° C.-50% RH atmosphere at 180 ° peel and a pulling speed of 300 mm / min. The glass plate surface and the adhesive layer surface were visually observed. The evaluation criteria are as follows.
4: The pressure-sensitive adhesive layer is not transferred to the glass plate surface at all, and the pressure-sensitive adhesive layer surface is also smooth.
3: The pressure-sensitive adhesive layer is not transferred to the glass plate surface, but slight unevenness is generated on the surface of the pressure-sensitive adhesive layer.
2: A part of the pressure-sensitive adhesive layer has been transferred to the surface of the glass plate, and remarkable unevenness has also occurred on the surface of the pressure-sensitive adhesive layer.
1: The adhesive layer has completely transferred to the glass plate surface.

<Light leakage phenomenon>
The adhesive composition obtained in each Example and each Comparative Example was applied to a polyester release film (thickness 38 μm) and dried at 90 ° C. for 60 seconds to form an adhesive layer having a thickness of 25 μm. A polarizing film (thickness: 180 μm) is attached to the adhesive layer, and left for 7 days in an atmosphere of 23 ° C.-50% RH to advance the reaction (aging), and the axial direction of the absorption axis of the polarizing film is To be at an angle of 45 °
In the case of Example 1, cut into 100 mm × 100 mm,
In the case of Examples 2-20 and Comparative Example 1, it cut | judged to 300 mm x 400 mm, and obtained the adhesive film 2, respectively.
The release film of the adhesive film 2 is peeled off, and the exposed adhesive layer is arranged on both surfaces of a 0.7 mm thick glass plate so that the axial directions of the absorption axes of the respective polarizing films are orthogonal to each other in a 50 ° C. atmosphere. After applying a pressure of 5 kg / cm ² and holding for 20 minutes for bonding, the substrate was left in an atmosphere at 80 ° C. for 500 hours and then returned to room temperature, and the presence or absence of light leakage from the four corners or peripheral edges was observed. The evaluation criteria are as follows.
4: No light leakage is observed.
3: Almost no light leakage is observed.
2: Light leakage is slightly noticeable on the whole.
1: Light leakage is confirmed remarkably.

<Heat resistance and moist heat resistance>
The release film of the adhesive film 2 described in the light leakage phenomenon is peeled off, and the exposed adhesive layer is applied to one side of a 0.7 mm thick glass plate under a pressure of 5 kg / cm ² in a 50 ° C. atmosphere for 20 minutes. After holding and bonding,
In the case of Example 1, 1000 hours in an atmosphere of 80 ° C.,
In the case of Examples 2 to 20 and Comparative Example 1, each was left in an atmosphere at 80 ° C. for 300 hours (heat resistance test).
Similarly, after the adhesive film 2 and the glass plate were bonded together, they were left in a constant temperature and humidity chamber of 60 ° C. to 90% RH for 300 hours (moisture and heat resistance test).
After standing, the temperature was returned to room temperature, and the adhesive film 2 was observed to float, peel and foam.
Foaming is a state in which relatively large bubbles are generated at the interface between the adhesive layer and the glass (other than the peripheral edge).
The floating / peeling is a state where the adhesive film 2 is lifted from the glass and peeled off. Each evaluation standard is as follows.
4: Not generated.
3: Minor occurrence is observed.
2: Occurrence is observed.
1: Significant occurrence is observed.

<Surface resistance value>
The release liner of the pressure-sensitive adhesive tape for test was peeled off, and the surface resistance value of the exposed pressure-sensitive adhesive layer surface was measured using a surface resistance value measurement device (manufactured by Mitsubishi Chemical Corporation) under each condition of 23 ° C.-45 and 55% RH. (Unit: Ω / □). “2.1E + 09” means “2.1 × 10 ⁹ ”.

  The above evaluation results are shown in Table 6.

Abbreviations in Table 6 are as follows.
Isocyanate curing agent: trimethylolpropane adduct of tolylene diisocyanate epoxy curing agent: N, N, N ′, N′-tetraglycidyl-m-xylenediamine silane coupling agent: 3-glycidoxypropyltri Methoxysilane

Claims (11)

A copolymer (C) having a hydroxyl group and / or a carboxyl group and having a glass transition temperature of −60 to 0 ° C., a compound (D) having a functional group capable of reacting with a hydroxyl group or a carboxyl group, and a compound (E1) Or an antistatic acrylic pressure-sensitive adhesive containing compound (E2),
The copolymer (C) is
<2> A high molecular weight component (A) and a low molecular weight component (B) are included (provided that the copolymer (C) is copolymerized with 5 to 35% by weight of an alkyl methacrylate having no substituent (note that , The total of the monomers constituting the copolymer (C) is 100% by weight)),
<2-1> A peak of a high molecular weight component (A1) having a weight average molecular weight of 500,000 to 2,200,000 completely independent on an emission curve in gel permeation chromatography, and a low weight average molecular weight of 1,000 to 100,000 The area ratio between the peak of the high molecular weight component (A1) and the peak of the low molecular weight component (B1) is (A1) / (B1) = 60 / 40-90. / 10, or
<2-2> The peak of the high molecular weight component (A2) having a weight average molecular weight of 500,000 to 2,200,000 and a weight average molecular weight of 1,000 to 100,000 located on both sides of the minimum value of the discharge curve in gel permeation chromatography The area ratio of the peak of the high molecular weight component (A2) to the peak of the low molecular weight component (B2) is (A2) / (B2) = 60/40. ~ 90/10, or <2-3> gel permeation chromatography comprising a polymer molecule having a molecular weight of 150,000 or more, and having a weight average molecular weight of 500,000 to 2,200,000 of a high molecular weight component (A3) A peak of a low molecular weight component (B3) composed of polymer molecules having a molecular weight of less than 150,000 and having a weight average molecular weight of 1,000 to 100,000, and the high molecular weight component (A3) And the area ratio of the low molecular weight component (B3) peak is (A3) / (B3) = 60/40 to 90/10,
An antistatic acrylic pressure-sensitive adhesive, wherein the compound (E1) is represented by the following general formula (1) and the compound (E2) is represented by the following general formula (2).

(In General Formula (1) and General Formula (2), R ¹ to R ⁸ are each independently a hydrogen atom, an alkyl group that may have a substituent, an alkenyl group that may have a substituent, An alkynyl group that may have a substituent, an aryl group that may have a substituent, or a heterocyclic group that may have a substituent, wherein R ⁵ to R ⁸ are adjacent to each other You may form a ring with
In the general formula (2), A ⁺ represents an alkali metal ion. ) 2. The antistatic acrylic pressure-sensitive adhesive according to claim 1, wherein R ^{1 to} R ⁴ are each independently an alkyl group which may have a substituent or an aryl group which may have a substituent. . The antistatic acrylic pressure-sensitive adhesive according to claim 1 or 2, wherein R ^{1 to} R ⁴ are each independently an aryl group which may have a substituent. The antistatic acrylic pressure-sensitive adhesive according to any one of claims 1 to 3, wherein R ^{5 to} R ⁸ are each independently an alkyl group which may have a substituent.   The compound (D) having a functional group capable of reacting with a hydroxyl group or a carboxyl group is contained in an amount of 0.01 to 10 parts by weight based on 100 parts by weight of the copolymer (C). Or an antistatic acrylic pressure-sensitive adhesive.   The antistatic acrylic pressure-sensitive adhesive according to any one of claims 1 to 6, wherein the hydroxyl group-containing monomer is hydroxyalkyl (meth) acrylate.   8. The antistatic acrylic pressure-sensitive adhesive according to claim 7, wherein the alkyl chain of hydroxyalkyl (meth) acrylate has 3 to 20 carbon atoms.   The copolymer (C) is an alkyl (meth) acrylate (a) having neither a hydroxyl group nor a carboxyl group, a monomer (b) having a hydroxyl group and / or a carboxyl group and an ethylenically unsaturated double bond , And if necessary, radically copolymerize the other radical polymerizable monomer (c) other than the above (a) and (b) until the polymerization conversion becomes 60 to 90%, and the weight average molecular weight is 500,000 to A copolymer containing 2.2 million high molecular weight components is obtained, then at least one of the above (a), (b) and (c) is added and further radical copolymerized until the polymerization conversion becomes 80 to 100%. The antistatic acrylic pressure-sensitive adhesive according to any one of claims 1 to 7, wherein Alkyl (meth) acrylate (a) having neither a hydroxyl group nor a carboxyl group, a monomer (b) having a hydroxyl group and / or a carboxyl group and an ethylenically unsaturated double bond, and, if necessary, ( a) Radical copolymerization of other radical polymerizable monomers (c) other than (b) until the polymerization conversion is 60 to 90%, and includes a high molecular weight component having a weight average molecular weight of 500,000 to 2,200,000. Obtain a copolymer,
Next, at least one of the above (a), (b) and (c) is added, and radical copolymerization is further carried out until the polymerization conversion becomes 80 to 100%. <2-1> On the discharge curve in gel permeation chromatography A completely independent high molecular weight component (A1) having a weight average molecular weight of 500,000 to 2,200,000 and a low molecular weight component (B1) peak having a weight average molecular weight of 1,000 to 100,000, the high molecular weight component The area ratio of the peak of the body (A1) and the peak of the low molecular weight component (B1) is (A1) / (B1) = 60/40 to 90/10, or
<2-2> The peak of the high molecular weight component (A2) having a weight average molecular weight of 500,000 to 2,200,000 and a weight average molecular weight of 1,000 to 100,000 located on both sides of the minimum value of the discharge curve in gel permeation chromatography The area ratio of the high molecular weight component (A2) peak to the low molecular weight component (B2) peak is (A2) / (B2) = 60/40 to 90 / Or in <2-3> gel permeation chromatography, a peak of a high molecular weight component (A3) consisting of polymer molecules having a molecular weight of 150,000 or more and having a weight average molecular weight of 500,000 to 2,200,000, A peak of a low molecular weight component (B3) consisting of polymer molecules having a molecular weight of less than 150,000 and having a weight average molecular weight of 1,000 to 100,000, and the peak of the high molecular weight component (A3) The area ratio to the low molecular weight component (B3) peak is (A3) / (B3) = 60/40 to 90/10.
A copolymer (C) having a hydroxyl group and / or a carboxyl group and having a glass transition temperature of −60 to 0 ° C. is obtained (excluding the case where 5 to 35% by weight of an alkyl methacrylate having no substituent is copolymerized ( Note that the total amount of monomers constituting the copolymer (C) is 100% by weight))),
Next, the copolymer (C), the compound (D) having a functional group capable of reacting with a hydroxyl group or a carboxyl group, the compound (E1) represented by the following general formula (1) or the following general formula (2) A method for producing an antistatic acrylic pressure-sensitive adhesive, comprising mixing the compound (E2) represented.

(In General Formula (1) and General Formula (2), R ¹ to R ⁸ are each independently a hydrogen atom, an alkyl group that may have a substituent, an alkenyl group that may have a substituent, An alkynyl group that may have a substituent, an aryl group that may have a substituent, or a heterocyclic group that may have a substituent, wherein R ⁵ to R ⁸ are adjacent to each other You may form a ring with
In the general formula (2), A ⁺ represents an alkali metal ion. )   An antistatic acrylic pressure-sensitive adhesive obtained by the production method according to claim 9.   The antistatic acrylic pressure-sensitive adhesive layer formed from the antistatic acrylic pressure-sensitive adhesive according to claim 1 is selected from the group consisting of a polarizing film and a retardation film. An antistatic acrylic pressure-sensitive adhesive film provided on at least one surface of an optical film.