WO2012121122A1 - Optical film having adhesive agent, and optical laminated body in which same is used - Google Patents

Abstract

The present invention provides an optical film having an adhesive agent, the optical film being provided with an adhesive agent layer obtained using a composition in which 0.3 to 12 parts by weight of an ionizable compound and 0.1 to 5 parts by weight of a cross-linking agent are compounded with 100 parts by weight of an acrylic copolymer of a monomer mixture comprising 80 to 96 wt% of (A-1), 1 to 15 wt% of (A-2), 0.1 to 5 wt% of (A-3), and 0.5 to 5 wt% of (A-4). (A-1) is a compound of formula (I) (R₁ is a hydrogen or methyl, and R₂ is a C_1-14 alkyl), (A-2) is an unsaturated monomer having an aromatic ring, (A-3) is a compound of formula (II) (R₃ is a hydrogen or methyl, R₄ is an alkyl, and m is 1 to 8), and (A-4) is an unsaturated monomer having a polar functional group.

Description

Optical film with adhesive and optical laminate using the same

The present invention relates to an optical film having an adhesive layer formed thereon. Examples of the optical film targeted by the present invention include a polarizing plate and a retardation film. The present invention also relates to an optical laminate for liquid crystal display using the optical film on which the pressure-sensitive adhesive layer is formed.

The polarizing plate is mounted on a liquid crystal display device and widely used. A polarizing plate generally circulates in a state where a transparent protective film is laminated on both sides of a polarizing film, an adhesive layer is formed on the surface of at least one protective film, and a release film is stuck on the adhesive layer. ing. In addition, a retardation film is laminated on a polarizing plate in which a protective film is bonded to both sides of the polarizing film to form an elliptical polarizing plate, and an adhesive layer / release film is attached in this order to the retardation film side. A protective film is bonded to one side of the polarizing film, and a retardation film is directly bonded to the other side to form an elliptical polarizing plate. The adhesive layer / release film is on the retardation film side. May be stuck in order. Furthermore, an adhesive layer / release film may be stuck in this order on the surface of the retardation film. In this specification, the polarizing plate, the elliptically polarizing plate, the retardation film and the like provided with the pressure-sensitive adhesive layer are collectively referred to as an optical film. Prior to bonding to the liquid crystal cell, the release film is peeled off from the optical film provided with these pressure-sensitive adhesive layers, and bonded to the liquid crystal cell via the exposed pressure-sensitive adhesive layer. Since the optical film provided with such an adhesive layer generates static electricity when the release film is peeled off and bonded to the liquid crystal cell, the development of a countermeasure for the prevention is desired.

Therefore, it has been proposed to blend a certain ionic compound in the pressure-sensitive adhesive composition and impart antistatic properties to the pressure-sensitive adhesive layer formed therefrom. For example, JP 2006-307238-A discloses blending an antistatic agent containing an organic salt having an organic nitrogen onium cation and a bis (perfluoroalkanesulfonyl) imide anion into a pressure-sensitive adhesive (adhesive). ing. JP 2004-114665-A discloses that an adhesive or the like contains a salt composed of a quaternary ammonium cation having 4 to 20 carbon atoms and a fluorine atom-containing anion. JP 2006-307238-A discloses that an ionic liquid that becomes liquid at room temperature (25 ° C.) is blended with an acrylic pressure-sensitive adhesive so that the acid value is 1.0 or less. JP2009-79205-A discloses that an ionic compound having an organic cation and solid at room temperature (25 ° C.) is blended in an acrylic pressure-sensitive adhesive. Furthermore, JP2010-66755-A discloses that an ionic compound having an organic cation is blended with an acrylic resin obtained by copolymerizing a monomer having an aromatic ring to form an adhesive.

It is also known to use an acrylic resin obtained by copolymerizing a (meth) acrylamide compound in an acrylic pressure-sensitive adhesive attached to an optical film. For example, in JP2007-264092-A, a crosslinking agent is added to an acrylic copolymer having monomer units of alkyl (meth) acrylate and N- (2-hydroxyethyl) (meth) acrylamide. It is disclosed that an optical pressure-sensitive adhesive is less likely to cause display unevenness in the peripheral portion of the screen. In JP2009-126929-A, an ionic compound is blended with a copolymer polymer in which (meth) acrylamide having a hydroxyl group and (meth) acrylic acid ester are copolymerized, and the aging time is short. And a pressure-sensitive adhesive composition capable of forming a pressure-sensitive adhesive layer having excellent antistatic performance is disclosed. Furthermore, JP2009-215528-A contains (meth) acrylic acid alkyl, (meth) acrylic acid ester having an aromatic ring, and (meth) acrylic acid ester having an amino group, and further has a carboxyl group and / or a hydroxyl group ( An acrylic resin obtained from a monomer mixture containing a (meth) acrylic acid ester and having a weight average molecular weight in the range of 1,600,000 to 3,000,000 is blended with an isocyanate-based crosslinking agent and a silane-based compound, and the dimensions of an optical film, etc. It is disclosed that an optical film pressure-sensitive adhesive composition that can suppress light leakage caused by a stress accompanying change and satisfy reworkability and workability, and instead of the (meth) acrylic acid ester having an amino group described above An example using N, N-dimethylaminopropylacrylamide is also shown.

On the other hand, an optical film with an adhesive as described above is bonded to a liquid crystal cell on the adhesive layer side to form a liquid crystal display device. In this state, the optical film is placed under high temperature or high temperature and high humidity conditions, or heated. If the cooling is repeated, foaming occurs in the pressure-sensitive adhesive layer with the dimensional change of the optical film, or floats or peels between the optical film and the pressure-sensitive adhesive layer, or between the pressure-sensitive adhesive layer and the liquid crystal cell glass. Therefore, it is required to have excellent durability without causing such problems.

The high temperature conditions to which the liquid crystal display device is exposed vary depending on the application of the liquid crystal display device. An optical film with an adhesive containing an ionic compound as described above as an antistatic agent may exhibit sufficient durability in a test in a general temperature range assuming a TV or a monitor. In a test under a more severe environment assuming an in-vehicle application or the like, floating or peeling still occurred between the pressure-sensitive adhesive layer and the liquid crystal cell glass. In particular, when the moisture permeability of the optical film to which the pressure-sensitive adhesive layer is bonded is low, this tendency is remarkable.

The problem of the present invention is that the antistatic property is imparted, and the adhesive layer is excellent in durability, and does not peel off even in a test under a harsh environment assuming an in-vehicle use or the like when bonded to glass. Is to provide an optical film with a pressure-sensitive adhesive provided on the surface of the optical film, which is laminated on a glass substrate to form an optical laminate having excellent durability. As a result of intensive studies to solve such problems, the present inventors have found that an unsaturated monomer, N-alkoxyalkyl (meta) containing (meth) acrylic acid ester as a main component and having an aromatic ring in the molecule. ) An acrylic resin obtained by copolymerizing at least four components of acrylamide and an unsaturated monomer having a polar functional group is blended with an ionic compound and a crosslinking agent to form a pressure-sensitive adhesive composition, which is used as an optical film. It has been found that it is effective to provide it as a pressure-sensitive adhesive layer on the surface, and the present invention has been achieved.

That is, the present invention includes the following.
[1] An optical film with an adhesive comprising an optical film and an adhesive layer formed on at least one surface thereof, the adhesive layer comprising 100 parts by weight of an acrylic copolymer (A), 0.3 Formed from a pressure-sensitive adhesive composition containing an ionic compound (B) having ~ 12 parts by weight of an organic cation and 0.1 to 5 parts by weight of a crosslinking agent (C),
The acrylic copolymer (A) is 80 to 96% by weight of (A-1), 1 to 15% by weight of (A-2), 0.1 to 5% by weight of (A-3), and Obtained from a monomer mixture containing 0.5 to 5% by weight of (A-4),
(A-1) represents the following formula (I)

(Wherein R ₁ represents a hydrogen atom or a methyl group, and R ₂ represents an alkyl group having 1 to 14 carbon atoms which may be substituted with an alkoxy group having 1 to 10 carbon atoms)
(Meth) acrylic acid ester represented by
(A-2) is an unsaturated monomer having one olefinic double bond and at least one aromatic ring in the molecule;
(A-3) is represented by the following formula (II)

(Wherein R ₃ represents a hydrogen atom or a methyl group, R ₄ represents an alkyl group, and m represents an integer of 1 to 8)
N-alkoxyalkyl (meth) acrylamide represented by
(A-4) is an unsaturated monomer having a polar functional group.

[2] The unsaturated monomer (A-2) having the above aromatic ring is a phenoxyethyl group-containing (meth) acrylic compound represented by the following formula (III), and the optical with pressure-sensitive adhesive according to [1] the film.

In the formula, R ₅ represents a hydrogen atom or a methyl group, n represents an integer of 1 to 8, and R ₆ represents a hydrogen atom, an alkyl group, an aralkyl group, or an aryl group.

[3] In the above formula (II) representing the N-alkoxyalkyl (meth) acrylamide (A-3), R ₄ is an alkyl group having 1 to 6 carbon atoms, and m is an integer of 1 to 4. The optical film with an adhesive as described in [1] or [2].

[4] The N-alkoxyalkyl (meth) acrylamide (A-3) is:
N- (methoxymethyl) acrylamide,
N- (ethoxymethyl) acrylamide,
N- (propoxymethyl) acrylamide,
N- (1-methylethoxymethyl) acrylamide,
N- (1-methylpropoxymethyl) acrylamide,
N- (2-methylpropoxymethyl) acrylamide,
N- (butoxymethyl) acrylamide,
N- (1,1-dimethylethoxymethyl) acrylamide,
N- (2-methoxyethyl) acrylamide,
N- (2-ethoxyethyl) acrylamide,
N- (2-propoxyethyl) acrylamide,
N- [2- (1-methylethoxy) ethyl] acrylamide,
N- [2- (1-methylpropoxy) ethyl] acrylamide,
N- [2- (2-methylpropoxy) ethyl] acrylamide,
The optical film with an adhesive according to [3], which is N- (2-butoxyethyl) acrylamide or N- [2- (1,1-dimethylethoxy) ethyl] acrylamide.

[5] The unsaturated monomer (A-4) having a polar functional group has a polar functional group selected from the group consisting of a free carboxyl group, a hydroxyl group, an amino group, and an epoxy ring [1] to [4]. An optical film with a pressure-sensitive adhesive according to any one of the above.

[6] The optical film with an adhesive according to any one of [1] to [5], wherein the crosslinking agent (C) contains an isocyanate compound.

[7] The pressure-sensitive adhesive composition further comprises 0.03 to 2 parts by weight of the silane compound (D) with respect to 100 parts by weight of the acrylic copolymer (A). An optical film with a pressure-sensitive adhesive according to claim 1.

[8] The optical film with an adhesive according to any one of [1] to [7], wherein the optical film is selected from the group consisting of a polarizing plate and a retardation film.

[9] The optical film with an adhesive according to any one of [1] to [8], wherein a release film is attached to the surface of the adhesive layer.

[10] The optical film with an adhesive according to any one of [1] to [8], which is laminated on the glass substrate and the adhesive layer side of the glass substrate.

The optical film with the pressure-sensitive adhesive of the present invention can effectively suppress the charging of the optical member on which it is adhered, and the pressure-sensitive adhesive layer is bonded to glass under high temperature or high temperature and high humidity conditions. Excellent durability when placed or repeated heating and cooling. In addition, after laminating the optical film with adhesive once on the glass substrate, even if the optical film is peeled off from the glass substrate together with the adhesive, adhesive residue or The fogging is less likely to occur and it can be used again as a glass substrate, resulting in excellent reworkability.

Hereinafter, the present invention will be described in detail. The optical film with pressure-sensitive adhesive of the present invention has a pressure-sensitive adhesive layer formed on at least one side of the optical film, and the pressure-sensitive adhesive layer is formed from a composition containing the following components (A) to (C). Is done.

(A) The main component is a structural unit derived from the (meth) acrylic acid ester (A-1) represented by the formula (I), and one olefinic double bond and at least one olefinic bond in the molecule. Structural unit derived from unsaturated monomer (A-2) having an aromatic ring, structural unit derived from N-alkoxyalkyl (meth) acrylamide (A-3) represented by formula (II), and polar functionality An acrylic copolymer containing a predetermined amount of structural units derived from an unsaturated monomer (A-4) having a group,
(B) an ionic compound having an organic cation, and (C) a crosslinking agent.

First, each component constituting the pressure-sensitive adhesive composition used for forming the pressure-sensitive adhesive layer will be described.

[Acrylic copolymer (A)]
In the optical film with pressure-sensitive adhesive of the present invention, the acrylic copolymer (A) constituting the pressure-sensitive adhesive composition used for forming the pressure-sensitive adhesive layer is (meth) acrylic acid represented by the above formula (I). The main unit is a structural unit derived from the ester (A-1). In addition to the structural unit derived from the (meth) acrylic acid ester (A-1), one olefinic double molecule is included in the molecule. A structural unit derived from an unsaturated monomer (A-2) having a bond and at least one aromatic ring, derived from an N-alkoxyalkyl (meth) acrylamide (A-3) represented by the formula (II) It includes a structural unit and a structural unit derived from an unsaturated monomer (A-4) having a polar functional group. Here, (meth) acrylic acid means that either acrylic acid or methacrylic acid may be used, and (meth) acrylamide means that either acrylamide or methacrylamide may be used. “(Meth)” when referring to acrylate, (meth) acryloyl, and the like has the same meaning.

In the formula (I), which is a main structural unit of the acrylic copolymer (A), R ₁ is a hydrogen atom or a methyl group, and R ₂ is an alkyl group having 1 to 14 carbon atoms. The alkyl group represented by R ₂ may be substituted with an alkoxy group having 1 to 10 carbon atoms. In this case, the alkoxy group replaces the hydrogen atom constituting the alkyl group.

Specific examples of the (meth) acrylic acid ester (A-1) represented by the formula (I) include methyl acrylate, ethyl acrylate, propyl acrylate, n-butyl acrylate, n-octyl acrylate, and Linear alkyl acrylates such as lauryl acrylate; branched alkyl alkyl esters such as isobutyl acrylate, 2-ethylhexyl acrylate, and isooctyl acrylate; methyl methacrylate, ethyl methacrylate, methacryl Linear alkyl methacrylates such as propyl acid, n-butyl methacrylate, n-octyl methacrylate, and lauryl methacrylate; branching such as isobutyl methacrylate, 2-ethylhexyl methacrylate, and isooctyl methacrylate Alkyl methacrylate Such esters are exemplified.

When R ₂ is an alkyl group substituted with an alkoxy group, that is, when R ₂ is an alkoxyalkyl group, the (meth) acrylic acid ester represented by the formula (I) is specifically acrylic acid. Examples include 2-methoxyethyl, ethoxymethyl acrylate, 2-methoxyethyl methacrylate, ethoxymethyl methacrylate, and the like.

These (meth) acrylic acid esters can be used alone or in combination with a plurality of different ones.

The unsaturated monomer (A-2) having one olefinic double bond and at least one aromatic ring in the molecule has a (meth) acryloyl group as a group containing an olefinic double bond. preferable. Such unsaturated monomers include benzyl (meth) acrylate, neopentyl glycol benzoate (meth) acrylate, and the like, and in particular, a phenoxyethyl group-containing (meth) acrylic compound represented by the formula (III) is preferable.

In the formula (III) representing the phenoxyethyl group-containing (meth) acrylic compound, R ₅ is a hydrogen atom or a methyl group, n is an integer of 1 to 8, and R ₆ is a hydrogen atom, an alkyl group, An aralkyl group or an aryl group; When R ₆ in formula (III) is an alkyl group, its carbon number can be about 1 to 9, and when it is also an aralkyl group, its carbon number is about 7 to 11 and is an aryl group. In this case, the carbon number can be about 6 to 10.

Specific examples of the (meth) acrylic compound represented by the formula (III) include (meth) acrylic acid 2-phenoxyethyl, (meth) acrylic acid 2- (2-phenoxyethoxy) ethyl, and ethylene oxide-modified nonylphenol ( And (meth) acrylic acid ester, (meth) acrylic acid 2- (o-phenylphenoxy) ethyl, and the like. These unsaturated monomers (A-2) having one olefinic double bond and at least one aromatic ring in these molecules may be used alone or in combination of two or more. Good. Among these, in particular, 2-methoxyethyl (meth) acrylate [compound of R ₆ = H, n = 1 in the above formula (III)], or 2- (2-phenoxyethoxy) ethyl (meth) acrylate [In the above formula (III), R ₆ = H, n = 2 compound] as one of unsaturated monomers (A-2) having an aromatic ring constituting the acrylic copolymer (A) It is preferable to use it.

In the formula (II) representing N-alkoxyalkyl (meth) acrylamide (A-3), R ₃ is a hydrogen atom or a methyl group, R ₄ is an alkyl group, and m is an integer of 1 to 8. . The alkyl group represented by R ₄ can have about 1 to 9 carbon atoms, but generally about 1 to 6 carbon atoms is sufficient. M is preferably in the range of 1 to 4.

With respect to such N-alkoxyalkyl (meth) acrylamide, taking acrylamide as an example, typical compound names are as follows.

N- (methoxymethyl) acrylamide,
N- (ethoxymethyl) acrylamide,
N- (propoxymethyl) acrylamide,
N- (1-methylethoxymethyl) acrylamide,
N- (1-methylpropoxymethyl) acrylamide,
N- (2-methylpropoxymethyl) acrylamide [also known as N- (isobutoxymethyl) acrylamide],
N- (butoxymethyl) acrylamide,
N- (1,1-dimethylethoxymethyl) acrylamide,
N- (2-methoxyethyl) acrylamide,
N- (2-ethoxyethyl) acrylamide,
N- (2-propoxyethyl) acrylamide,
N- [2- (1-methylethoxy) ethyl] acrylamide,
N- [2- (1-methylpropoxy) ethyl] acrylamide,
N- [2- (2-methylpropoxy) ethyl] acrylamide [also known as N- (2-isobutoxyethyl) acrylamide],
N- (2-butoxyethyl) acrylamide,
N- [2- (1,1-dimethylethoxy) ethyl] acrylamide and the like.

Of course, compounds obtained by replacing these acrylamides with methacrylamide can also be N-alkoxyalkyl (meth) acrylamides (A-3). As these N-alkoxyalkyl (meth) acrylamides, one kind of compound corresponding to the formula (II) may be used alone, or two or more kinds thereof may be used in combination. Among these, N- (methoxymethyl) acrylamide, N- (ethoxymethyl) acrylamide, N- (propoxymethyl) acrylamide, N- (butoxymethyl) acrylamide, or N- (2-methylpropoxymethyl) acrylamide is particularly preferable. Preferably used.

The N-alkoxyalkyl (meth) acrylamide represented by the formula (II) constitutes a pressure-sensitive adhesive composition mainly composed of an acrylic copolymer (A) copolymerized at a predetermined ratio, and the pressure-sensitive adhesive composition. An optical film provided with a pressure-sensitive adhesive layer formed from a product is effective in enhancing durability when exposed to high temperatures, particularly around 100 ° C. In order to prevent the adhesive layer from adhering firmly when it comes into contact with a certain type of release film, this N-alkoxyalkyl (meth) acrylamide has a tertiary amino group. The structure does not.

The unsaturated monomer (A-4) having a polar functional group reacts with the cross-linking agent (C) described later by the acrylic copolymer (A) having the copolymer component as a cross-linking structure in the pressure-sensitive adhesive layer. Is used to develop a cohesive force. Examples include monomers having free carboxyl groups such as acrylic acid, methacrylic acid, and 2-carboxyethyl acrylate; 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, ( Monomers having a hydroxyl group, such as 2- or 3-chloro-2-hydroxypropyl methacrylate and diethylene glycol mono (meth) acrylate; acryloylmorpholine, vinylcaprolactam, N-vinyl-2-pyrrolidone, tetrahydrofurfuryl A monomer having a heterocyclic group such as (meth) acrylate, caprolactone-modified tetrahydrofurfuryl acrylate, 3,4-epoxycyclohexylmethyl (meth) acrylate, glycidyl (meth) acrylate, and 2,5-dihydrofuran; N , N- Such as methyl aminoethyl (meth) acrylate, and the like monomers having different amino group and heterocyclic.
These monomers having polar functional groups may be used alone or in combination of two or more.

Among these, it is preferable to use a monomer having a hydroxyl group as one of unsaturated monomers (A-4) having a polar functional group constituting the acrylic copolymer (A). In addition to the monomer having a hydroxyl group, it is also effective to use a monomer having another polar functional group, for example, a monomer having a free carboxyl group.

The acrylic copolymer (A) used for forming the pressure-sensitive adhesive layer contains 80 to 96% by weight of (meth) acrylic acid ester (A-1) represented by the above formula (I), one in the molecule. 1 to 15% by weight of an unsaturated monomer (A-2) having an olefinic double bond and at least one aromatic ring, N-alkoxyalkyl (meth) acrylamide represented by the formula (II) (A- 3) a copolymer obtained from a monomer mixture containing 0.1 to 5% by weight and an unsaturated monomer (A-4) having a polar functional group in a proportion of 0.5 to 5% by weight. is there. An optical film having a pressure-sensitive adhesive layer formed from a pressure-sensitive adhesive composition containing the acrylic copolymer (A) as a main component by copolymerizing at least four components at a predetermined ratio has a heat and moisture resistance, 80 While maintaining durability at a temperature of about 100 ° C. and heat shock resistance, durability at a high temperature of about 100 ° C. is particularly enhanced. A preferred copolymerization ratio of the (meth) acrylic acid ester (A-1) is 82 to 92% by weight. A preferable copolymerization ratio of the unsaturated monomer (A-2) having an aromatic ring is 3 to 15% by weight, and further 7 to 12% by weight. A preferred copolymerization ratio of N-alkoxyalkyl (meth) acrylamide (A-3) is 0.1 to 2% by weight, and further 0.1 to 1% by weight. The preferred copolymerization ratio of the unsaturated monomer (A-4) having a polar functional group is 0.5 to 3% by weight. Of course, in the monomer mixture used as a raw material for the acrylic copolymer (A), (meth) acrylic acid ester (A-1), unsaturated monomer having an aromatic ring (A-2), N-alkoxy The total amount of alkyl (meth) acrylamide (A-3) and unsaturated monomer (A-4) having a polar functional group does not exceed 100% by weight.

The acrylic copolymer (A) used in the present invention includes the above-described (meth) acrylic acid ester (A-1), unsaturated monomer having an aromatic ring (A-2), and N-alkoxyalkyl. A structural unit derived from a monomer other than (meth) acrylamide (A-3) and an unsaturated monomer (A-4) having a polar functional group may be included. Examples of these include structural units derived from (meth) acrylic acid esters having an alicyclic structure in the molecule, structural units derived from styrene monomers, structural units derived from vinyl monomers, molecules Examples thereof include a structural unit derived from a monomer having a plurality of (meth) acryloyl groups.

The (meth) acrylic acid ester having an alicyclic structure will be described. The alicyclic structure is a cycloparaffin structure having usually 5 or more carbon atoms, preferably about 5 to 7 carbon atoms. Specific examples of the acrylate ester having an alicyclic structure include isobornyl acrylate, cyclohexyl acrylate, dicyclopentanyl acrylate, cyclododecyl acrylate, methyl cyclohexyl acrylate, trimethyl cyclohexyl acrylate, tert-acrylate acrylate Examples include butyl cyclohexyl, α-ethoxy acrylate cyclohexyl, cyclohexyl phenyl acrylate, and the like. Specific examples of the methacrylic acid ester having an alicyclic structure include isobornyl methacrylate, cyclohexyl methacrylate, dicyclopentanyl methacrylate, cyclododecyl methacrylate, methyl cyclohexyl methacrylate, trimethyl cyclohexyl methacrylate, methacrylic acid. Examples include tert-butylcyclohexyl and cyclohexylphenyl methacrylate.

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

Examples of vinyl monomers include vinyl acetate, vinyl propionate, vinyl butyrate, vinyl 2-ethylhexanoate and vinyl laurate such as vinyl esters; vinyl halides such as vinyl chloride and vinyl bromide; There are vinylidene halides such as vinylidene chloride; nitrogen-containing aromatic vinyls such as vinylpyridine, vinylpyrrolidone, and vinylcarbazole; conjugated diene monomers such as butadiene, isoprene, and chloroprene; and acrylonitrile, methacrylonitrile, and the like.

Examples of monomers having a plurality of (meth) acryloyl groups in the molecule include ethylene glycol di (meth) acrylate, 1,4-butanediol di (meth) acrylate, and 1,6-hexanediol di (meth). ) Acrylate, 1,9-nonanediol di (meth) acrylate, diethylene glycol di (meth) acrylate, tetraethylene glycol di (meth) acrylate, and tripropylene glycol di (meth) acrylate. Monomers having a meth) acryloyl group; monomers having three (meth) acryloyl groups in the molecule, such as trimethylolpropane tri (meth) acrylate.

These monomers other than (A-1) to (A-4) can be used alone or in combination of two or more. In the acrylic copolymer (A), when the monomers other than (A-1) to (A-4) are copolymerized, the amount thereof is the total amount constituting the acrylic copolymer (A). It is usually 20% by weight or less, preferably 10% by weight or less, based on the body.

The acrylic copolymer constituting the pressure-sensitive adhesive composition is the above-described (meth) acrylic acid ester (A-1) represented by the formula (I), at least one olefinic double bond in the molecule and at least Unsaturated monomer (A-2) having one aromatic ring, N-alkoxyalkyl (meth) acrylamide (A-3) represented by formula (II), and unsaturated monomer having a polar functional group Two or more types of acrylic copolymers (A) having a structural unit derived from (A-4) in a predetermined ratio may be mixed. In addition, an acrylic resin different from the acrylic copolymer (A) obtained by copolymerizing the monomers (A-1) to (A-4) at a predetermined ratio may be mixed. The different acrylic resins mixed in this case can be, for example, those having a structural unit derived from the (meth) acrylic ester of the formula (I) and having no polar functional group. An acrylic copolymer containing structural units derived from (A-1) to (A-4) comprises an acrylic copolymer containing structural units derived from (A-1) to (A-4), and Is preferably 80% by weight or more, more preferably 90% by weight or more of the total of different acrylic resins.

(Meth) acrylic acid ester (A-1), unsaturated monomer (A-2) having an aromatic ring, N-alkoxyalkyl (meth) acrylamide (A-3), and unsaturated monomer having a polar functional group The acrylic copolymer (A) which is a copolymer obtained from the monomer mixture containing the monomer (A-4) has a weight average molecular weight Mw in terms of standard polystyrene by gel permeation chromatography (GPC). It is preferably in the range of 500,000 to 2,000,000. If this weight average molecular weight is too small, the adhesiveness under high temperature and high humidity is reduced, the possibility of floating or peeling between the glass substrate and the adhesive layer is increased, and the reworkability is reduced. The lower limit is set to 500,000. In addition, when the weight average molecular weight is 2 million or less, even if the dimension of the optical film bonded to the pressure-sensitive adhesive layer using the same changes, the pressure-sensitive adhesive layer changes following the dimensional change. The difference between the brightness of the peripheral edge of the liquid crystal cell and the brightness of the central portion is eliminated, and this is preferable because white spots and color unevenness tend to be suppressed.

The preferred weight average molecular weight of the acrylic copolymer (A) varies depending on the material of the pressure-sensitive adhesive layer-forming surface of the optical film on which the pressure-sensitive adhesive layer using this resin is formed. Conventionally, the weight average molecular weight of the acrylic resin constituting the acrylic pressure-sensitive adhesive is generally required to be at least about 1 million. On the other hand, in the acrylic copolymer (A) in which N-alkoxyalkyl (meth) acrylamide (A-3) is copolymerized according to the present invention, the pressure-sensitive adhesive layer forming surface of the optical film is acetylcellulose. An acrylic copolymer (A) that forms a pressure-sensitive adhesive layer as long as it is a film that shows a moisture permeability greater than about 300 g / (m ² · 24 hr) at a temperature of 40 ° C. and a relative humidity of 90%, such as a resin-based resin film. ) Even when the weight average molecular weight is relatively small, about 500 to 1,000,000. When such a resin film having a high moisture permeability is used as the pressure-sensitive adhesive layer forming surface, the acrylic copolymer (A) may of course have a large value within a range of 2 million or less, as well as the weight average molecular weight. . The moisture permeability will be described again later in the section “Optical film with adhesive”. As a typical optical film in which a resin film showing a relatively large moisture permeability becomes the pressure-sensitive adhesive layer forming surface, a protective film or retardation film made of an acetylcellulose-based resin on one side of a polarizing film made of a polyvinyl alcohol-based resin film described later Can be mentioned. In this case, the surface of the acetylcellulose-based resin film is the pressure-sensitive adhesive layer-forming surface, and a protective film made of acetylcellulose-based resin is provided on the polarizing film surface opposite to the surface to which the acetylcellulose-based resin film is bonded. It can also bond and another protective film can also be bonded.

On the other hand, the pressure-sensitive adhesive layer forming surface of the optical film has a temperature of 40 ° C. and a relative humidity of 90%, such as a polyolefin film, a cycloolefin-based resin film itself, or a retardation film obtained by uniaxially or biaxially stretching them. In the case of a resin film having a small moisture permeability of approximately 300 g / (m ² · 24 hr) or less under the conditions, if the weight average molecular weight of the acrylic resin forming the adhesive layer is small, the adhesive layer is applied to the glass substrate. When pasted, there is a tendency that floating or peeling is likely to occur between the glass substrate and the pressure-sensitive adhesive layer. Therefore, in this case, the acrylic copolymer (A) preferably has a weight average molecular weight of 1 million or more. Also from the viewpoint of improving the adhesiveness under high temperature and high humidity, the acrylic copolymer (A) preferably has a weight average molecular weight of 1,000,000 or more. As a typical optical film in which a resin film exhibiting a relatively small moisture permeability serves as a pressure-sensitive adhesive layer forming surface, a polyolefin film or a cycloolefin resin is provided on one side of a polarizing film comprising a polyvinyl alcohol-based resin film described later. A polarizing plate on which a retardation film obtained by uniaxial stretching or biaxial stretching of a film is bonded can be mentioned. In this case, the retardation film surface becomes the pressure-sensitive adhesive layer forming surface, and an arbitrary protective film can be bonded to the polarizing film surface opposite to the surface to which the retardation film is bonded.

Furthermore, the acrylic copolymer (A) usually has a molecular weight distribution represented by a ratio Mw / Mn of the weight average molecular weight Mw and the number average molecular weight Mn in the range of about 3 to 7.

The acrylic copolymer (A) constituting the pressure-sensitive adhesive composition can be produced by various known methods such as a solution polymerization method, an emulsion polymerization method, a bulk polymerization method, and a suspension polymerization method. In the production of this acrylic copolymer, a polymerization initiator is usually used. The polymerization initiator is used in an amount of about 0.001 to 5 parts by weight with respect to a total of 100 parts by weight of all monomers used in the production of the acrylic copolymer.

As the polymerization initiator, a thermal polymerization initiator, a photopolymerization initiator, or the like is used. Examples of the photopolymerization initiator include 4- (2-hydroxyethoxy) phenyl (2-hydroxy-2-propyl) ketone. Examples of the thermal polymerization initiator 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-methylpropio) And azo compounds such as 2,2'-azobis (2-hydroxymethylpropionitrile); lauryl peroxide, tert-butyl hydroperoxide, benzoyl peroxide, tert-butyl peroxybenzoate, cumene hydroper Oxide, diisopropyl peroxydicarbonate, dipropyl peroxydicarbonate, te Organic peroxides such as t-butyl peroxyneodecanoate, tert-butyl peroxypivalate, and (3,5,5-trimethylhexanoyl) peroxide; potassium persulfate, ammonium persulfate, and hydrogen peroxide Inorganic peroxides such as A redox initiator using a peroxide and a reducing agent in combination can also be used as the polymerization initiator.

As a method for producing the acrylic copolymer, the solution polymerization method is preferable among the methods shown above.
A specific example of the solution polymerization method will be described. A desired monomer and an organic solvent are mixed, and a thermal polymerization initiator is added under a nitrogen atmosphere, and the temperature is about 40 to 90 ° C., preferably 60 to 80. A method of stirring at about 0 ° C. for about 3 to 10 hours can be mentioned. Moreover, in order to control reaction, you may add a monomer and a thermal-polymerization initiator continuously or intermittently during superposition | polymerization, or may be added in the state melt | dissolved in the organic solvent. Examples of the organic solvent include aromatic hydrocarbons such as toluene and xylene; esters such as ethyl acetate and butyl acetate; aliphatic alcohols such as propyl alcohol and isopropyl alcohol; acetone, methyl ethyl ketone, and methyl isobutyl. Ketones such as ketones can be used.

[Ionic compound (B)]
An ionic compound (B) is mix | blended in order to provide electroconductivity to an adhesive layer and to improve the antistatic property of an optical film. The cation component which comprises an ionic compound (B) will not be specifically limited if it is an organic cation. For example, pyridinium cation, imidazolium cation, pyrrolidinium cation, ammonium cation, sulfonium cation, phosphonium cation, etc. can be mentioned. When used in the adhesive layer of an optical film, when peeling the release film provided on it From the viewpoint of being hardly charged, a pyridinium cation or an imidazolium cation is preferable.

On the other hand, in the ionic compound (B), the anion component serving as a counter ion of the cation component is not particularly limited, and may be an inorganic anion or an organic anion. The following can be mentioned.

Chloride anion [Cl ⁻ ],
Bromide anion [Br ⁻ ],
Iodide anion [I ⁻ ],
Tetrachloroaluminate anion [AlCl ₄ ⁻ ],
Heptachlorodialuminate anion [Al ₂ Cl ₇ ⁻ ],
Tetrafluoroborate anion [BF ₄ ⁻ ],
Hexafluorophosphate anion [PF ₆ ⁻ ],
Perchlorate anion [ClO ₄ ⁻ ],
Nitrate anion [NO ₃ ⁻ ],
Acetate anion [CH ₃ COO ⁻ ],
Trifluoroacetate anion [CF ₃ COO ⁻ ],
Methanesulfonate anion [CH ₃ SO ₃ ⁻ ],
Trifluoromethanesulfonate anion [CF ₃ SO ₃ ⁻ ],
p-toluenesulfonate anion [p-CH ₃ C ₆ H ₄ SO ₃ ⁻ ],
Bis (fluorosulfonyl) imide anion [(FSO ₂ ) ₂ N ⁻ ],
Bis (trifluoromethanesulfonyl) imide anion [(CF ₃ SO ₂ ) ₂ N ⁻ ],
Tris (trifluoromethanesulfonyl) methanide anion [(CF ₃ SO ₂ ) ₃ C ⁻ ], hexafluoroarsenate anion [AsF ₆ ⁻ ],
Hexafluoroantimonate anion [SbF ₆ ⁻ ],
Hexafluoroniobate anion [NbF ₆ ⁻ ],
Hexafluorotantalate anion [TaF ₆ ⁻ ],
Dimethyl phosphinate anion [(CH ₃ ) ₂ POO ⁻ ],
(Poly) hydrofluorofluoride anion [F (HF) _n ⁻ ] (n is about 1 to 3),
Dicyanamide anion [(CN) ₂ N ⁻ ],
Thiocyan anion [SCN ⁻ ],
Perfluorobutanesulfonate anion [C ₄ F ₉ SO ₃ ⁻ ],
Bis (pentafluoroethanesulfonyl) imide anion [(C ₂ F ₅ SO ₂ ) ₂ N ⁻ ], perfluorobutanoate anion [C ₃ F ₇ COO ⁻ ],
(Trifluoromethanesulfonyl) (trifluoromethanecarbonyl) imide anion [(CF ₃ SO ₂ ) (CF ₃ CO) N ⁻ ] and the like.

Among these, in particular, an anion component containing a fluorine atom is preferably used because it provides an ionic compound having excellent antistatic performance, and in particular, bis (fluorosulfonyl) imide anion, hexafluorophosphate anion, and bis (trifluoromethane). A sulfonyl) imide anion is preferred.

Specific examples of the ionic compound used in the present invention can be appropriately selected from a combination of the cation component and the anion component. Specific examples of the compound that is a combination of a cation component and an anion component include the following.

・ Pyridinium salt:
N-hexylpyridinium hexafluorophosphate,
N-octylpyridinium hexafluorophosphate,
N-methyl-4-hexylpyridinium hexafluorophosphate,
N-butyl-4-methylpyridinium hexafluorophosphate,
N-octyl-4-methylpyridinium hexafluorophosphate,
N-hexylpyridinium bis (fluorosulfonyl) imide,
N-octylpyridinium bis (fluorosulfonyl) imide,
N-methyl-4-hexylpyridinium bis (fluorosulfonyl) imide,
N-butyl-4-methylpyridinium bis (fluorosulfonyl) imide,
N-octyl-4-methylpyridinium bis (fluorosulfonyl) imide,
N-hexylpyridinium bis (trifluoromethanesulfonyl) imide,
N-octylpyridinium bis (trifluoromethanesulfonyl) imide,
N-methyl-4-hexylpyridinium bis (trifluoromethanesulfonyl) imide,
N-butyl-4-methylpyridinium bis (trifluoromethanesulfonyl) imide,
N-octyl-4-methylpyridinium bis (trifluoromethanesulfonyl) imide,
N-hexylpyridinium p-toluenesulfonate,
N-octylpyridinium p-toluenesulfonate,
N-methyl-4-hexylpyridinium p-toluenesulfonate,
N-butyl-4-methylpyridinium p-toluenesulfonate,
N-octyl-4-methylpyridinium p-toluenesulfonate and the like.

・ Imidazolium salt:
1-ethyl-3-methylimidazolium hexafluorophosphate,
1-ethyl-3-methylimidazolium bis (fluorosulfonyl) imide,
1-ethyl-3-methylimidazolium bis (trifluoromethanesulfonyl) imide,
1-ethyl-3-methylimidazolium p-toluenesulfonate,
1-butyl-3-methylimidazolium methanesulfonate and the like.

・ Pyrrolidinium salt:
N-butyl-N-methylpyrrolidinium hexafluorophosphate,
N-butyl-N-methylpyrrolidinium bis (fluorosulfonyl) imide,
N-butyl-N-methylpyrrolidinium bis (trifluoromethanesulfonyl) imide,
N-butyl-N-methylpyrrolidinium p-toluenesulfonate and the like.

・ Ammonium salt:
Tetrabutylammonium hexafluorophosphate,
Tetrabutylammonium bis (fluorosulfonyl) imide,
Tetrahexylammonium bis (fluorosulfonyl) imide,
Trioctylmethylammonium bis (fluorosulfonyl) imide,
(2-hydroxyethyl) trimethylammonium bis (fluorosulfonyl) imide,
Tetrabutylammonium bis (trifluoromethanesulfonyl) imide,
Tetrahexylammonium bis (trifluoromethanesulfonyl) imide,
Trioctylmethylammonium bis (trifluoromethanesulfonyl) imide,
(2-hydroxyethyl) trimethylammonium bis (trifluoromethanesulfonyl) imide,
Tetrabutylammonium p-toluenesulfonate,
Tetrahexylammonium p-toluenesulfonate,
Trioctylmethylammonium p-toluenesulfonate,
(2-hydroxyethyl) trimethylammonium p-toluenesulfonate,
(2-hydroxyethyl) trimethylammonium dimethylphosphinate and the like.

Such ionic compounds (B) can be used alone or in combination of two or more. Of course, examples of the ionic compound (B) are not limited to the substances listed above.

As described above, the ionic compound (B) imparts antistatic properties to the pressure-sensitive adhesive layer formed from the pressure-sensitive adhesive composition containing the acrylic copolymer (A) and maintains various physical properties as a pressure-sensitive adhesive. It is effective in. In particular, the ionic compound (B) is solid at room temperature (25 ° C.) from the viewpoint of long-term stability of antistatic properties as compared with the case of using an ionic compound that is liquid at room temperature (25 ° C.). Specifically, those having a melting point of 30 ° C. or higher, more preferably 35 ° C. or higher are preferable. On the other hand, when the melting point is too high, the compatibility with the acrylic copolymer (A) is deteriorated, and therefore, it preferably has a melting point of 80 ° C. or lower, more preferably 70 ° C. or lower.

The ionic compound (B) is blended in an amount of 0.3 to 12 parts by weight with respect to 100 parts by weight of the acrylic copolymer (A). If the ionic compound (B) is contained in an amount of 0.3 parts by weight or more with respect to 100 parts by weight of the acrylic copolymer (A), the antistatic performance is improved, and the amount is 12 parts by weight or less. It is preferable because durability is easy to maintain. The amount of the ionic compound (B) with respect to 100 parts by weight of the acrylic copolymer (A) is preferably 0.5 parts by weight or more and 3 parts by weight or less.

[Crosslinking agent (C)]
In addition to the acrylic copolymer (A) and the ionic compound (B) as described above, a crosslinking agent (C) is blended to obtain a pressure-sensitive adhesive composition. The crosslinking agent (C) contains at least 2 functional groups capable of crosslinking with a structural unit derived from the unsaturated monomer (A-4) having a polar functional group in the acrylic copolymer (A). Specific examples include isocyanate compounds, epoxy compounds, metal chelate compounds, aziridine compounds, and the like.

Isocyanate compounds are compounds having at least two isocyanato groups (-NCO) in the molecule, such as tolylene diisocyanate, hexamethylene diisocyanate, isophorone diisocyanate, xylylene diisocyanate, hydrogenated xylylene diisocyanate, diphenylmethane diisocyanate, Examples thereof include hydrogenated diphenylmethane diisocyanate, naphthalene diisocyanate, and triphenylmethane triisocyanate. In addition, adducts obtained by reacting these isocyanate compounds with polyols such as glycerol and trimethylolpropane, and those obtained by converting isocyanate compounds into dimers, trimers, and the like can also be used as crosslinking agents for pressure-sensitive adhesives. Two or more isocyanate compounds can be mixed and used.

The epoxy compound is a compound having at least two epoxy groups in the molecule, for example, bisphenol A type epoxy resin, ethylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, glycerin diglycidyl ether, glycerin triglycidyl ether. 1,6-hexanediol diglycidyl ether, trimethylolpropane triglycidyl ether, N, N-diglycidylaniline, N, N, N ′, N′-tetraglycidyl-m-xylenediamine, 1,3-bis ( N, N'-diglycidylaminomethyl) cyclohexane and the like. Two or more types of epoxy compounds can be mixed and used.

Examples of the metal chelate compound include compounds in which acetylacetone or ethyl acetoacetate is coordinated to a polyvalent metal such as aluminum, iron, copper, zinc, tin, titanium, nickel, antimony, magnesium, vanadium, chromium, and zirconium. Can be mentioned.

An aziridine-based compound is a compound having at least two skeletons of a three-membered ring composed of one nitrogen atom and two carbon atoms, also called ethyleneimine, for example, diphenylmethane-4,4′-bis ( 1-aziridinecarboxamide), toluene-2,4-bis (1-aziridinecarboxamide), triethylenemelamine, isophthaloylbis-1- (2-methylaziridine), tris-1-aziridinylphosphine oxide, hexamethylene -1,6-bis (1-aziridinecarboxamide), trimethylolpropane tris-β-aziridinylpropionate, tetramethylolmethane tris-β-aziridinylpropionate, and the like.

Among these crosslinking agents, isocyanate compounds, particularly xylylene diisocyanate, tolylene diisocyanate or hexamethylene diisocyanate, or adducts obtained by reacting these isocyanate compounds with polyols such as glycerol and trimethylolpropane, and isocyanates Mixtures of compounds made of dimers, trimers, etc., and mixtures of these isocyanate compounds are preferably used.
Examples of suitable isocyanate compounds include tolylene diisocyanate, adducts obtained by reacting tolylene diisocyanate with polyols, dimers of tolylene diisocyanate, and trimers of tolylene diisocyanate, hexamethylene diisocyanate, and hexamethylene diisocyanate. Examples include adducts reacted with polyols, dimers of hexamethylene diisocyanate, and trimers of hexamethylene diisocyanate.

The crosslinking agent (C) is blended at a ratio of 0.1 to 5 parts by weight with respect to 100 parts by weight of the acrylic copolymer (A). The preferable blending amount is about 0.2 to 3 parts by weight with respect to 100 parts by weight of the acrylic copolymer (A). The blending amount of the crosslinking agent (C) with respect to 100 parts by weight of the acrylic copolymer (A) is preferably 0.1 parts by weight or more because the durability of the pressure-sensitive adhesive layer tends to be improved, and 5% by weight. When the amount is less than or equal to the portion, white spots are not noticeable when the optical film with an adhesive is applied to a liquid crystal display device.

[Other components constituting the adhesive]
In the present invention, the pressure-sensitive adhesive for forming the pressure-sensitive adhesive layer preferably contains a silane compound (D) in order to improve the adhesion between the pressure-sensitive adhesive layer and the glass substrate. It is preferable to contain the silane compound (D) in the acrylic copolymer before blending C).

Silane compounds have a hydrolyzable group such as an alkoxy group bonded to a silicon atom and a reactive functional group such as a vinyl group, amino group, epoxy group, haloalkyl group, (meth) acryloyl group or mercapto group. It may be a compound having an organic group bonded thereto. Illustrating each specific compound, examples of the silane compound having a vinyl group include vinyltrimethoxysilane, vinyltriethoxysilane, and vinyltris (2-methoxyethoxy) silane. Examples of the silane compound having an amino group include N- (2-aminoethyl) -3-aminopropylmethyldimethoxysilane, N- (2-aminoethyl) -3-aminopropyltrimethoxysilane, and 3-aminopropyltriethoxy. There are silanes. Silane compounds having an epoxy group include 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropyltriethoxysilane, 3-glycidoxypropyldimethoxymethylsilane, 3-glycidoxypropylethoxydimethylsilane, 2- (3,4-epoxycyclohexyl) ethyltrimethoxysilane and the like. Examples of the silane compound having a haloalkyl group include 3-chloropropylmethyldimethoxysilane and 3-chloropropyltrimethoxysilane. Examples of the silane compound having a (meth) acryloyl group include 3- (meth) acryloyloxypropyltrimethoxysilane. Examples of the silane compound having a mercapto group include 3-mercaptopropyltrimethoxysilane. Two or more silane compounds (D) may be used in combination.

The silane compound (D) may be of a silicone oligomer type. When the silicone oligomer is shown in the form of (monomer)-(monomer) copolymer, for example, the following can be mentioned.

3-mercaptopropyltrimethoxysilane-tetramethoxysilane copolymer, 3-mercaptopropyltrimethoxysilane-tetraethoxysilane copolymer, 3-mercaptopropyltriethoxysilane-tetramethoxysilane copolymer, and 3-mercaptopropyltriethoxysilane-tetraethoxy A copolymer containing a mercaptopropyl group, such as a silane copolymer;

Mercaptomethyl groups such as mercaptomethyltrimethoxysilane-tetramethoxysilane copolymer, mercaptomethyltrimethoxysilane-tetraethoxysilane copolymer, mercaptomethyltriethoxysilane-tetramethoxysilane copolymer, and mercaptomethyltriethoxysilane-tetraethoxysilane copolymer. Containing copolymers;

3-methacryloyloxypropyltrimethoxysilane-tetramethoxysilane copolymer, 3-methacryloyloxypropyltrimethoxysilane-tetraethoxysilane copolymer, 3-methacryloyloxypropyltriethoxysilane-tetramethoxysilane copolymer, 3-methacryloyloxypropyltriethoxysilane -Tetraethoxysilane copolymer, 3-methacryloyloxypropylmethyldimethoxysilane-tetramethoxysilane copolymer, 3-methacryloyloxypropylmethyldimethoxysilane-tetraethoxysilane copolymer, 3-methacryloyloxypropylmethyldiethoxysilane-tetramethoxysilane copolymer, and 3-methacryloxyyl propylmethyldiethoxysilane-teto Such as silane copolymer, methacryloyloxypropyl group containing copolymers;

3-acryloyloxypropyltrimethoxysilane-tetramethoxysilane copolymer, 3-acryloyloxypropyltrimethoxysilane-tetraethoxysilane copolymer, 3-acryloyloxypropyltriethoxysilane-tetramethoxysilane copolymer, 3-acryloyloxypropyltriethoxysilane -Tetraethoxysilane copolymer, 3-acryloyloxypropylmethyldimethoxysilane-tetramethoxysilane copolymer, 3-acryloyloxypropylmethyldimethoxysilane-tetraethoxysilane copolymer, 3-acryloyloxypropylmethyldiethoxysilane-tetramethoxysilane copolymer, and 3-acryloyloxypropylmethyldiethoxysilane-tetraethoxysilane Such polymers, acryloyloxy propyl group-containing copolymer;

Vinyltrimethoxysilane-tetramethoxysilane copolymer, vinyltrimethoxysilane-tetraethoxysilane copolymer, vinyltriethoxysilane-tetramethoxysilane copolymer, vinyltriethoxysilane-tetraethoxysilane copolymer, vinylmethyldimethoxysilane-tetramethoxysilane copolymer, Vinyl group-containing copolymers such as vinylmethyldimethoxysilane-tetraethoxysilane copolymer, vinylmethyldiethoxysilane-tetramethoxysilane copolymer, and vinylmethyldiethoxysilane-tetraethoxysilane copolymer;

3-aminopropyltrimethoxysilane-tetramethoxysilane copolymer, 3-aminopropyltrimethoxysilane-tetraethoxysilane copolymer, 3-aminopropyltriethoxysilane-tetramethoxysilane copolymer, 3-aminopropyltriethoxysilane-tetraethoxysilane Copolymer, 3-aminopropylmethyldimethoxysilane-tetramethoxysilane copolymer, 3-aminopropylmethyldimethoxysilane-tetraethoxysilane copolymer, 3-aminopropylmethyldiethoxysilane-tetramethoxysilane copolymer, and 3-aminopropylmethyldiethoxy Amino group-containing copolymers such as silane-tetraethoxysilane copolymers.

These silane compounds (D) are often liquids. When a silane compound is added to the pressure-sensitive adhesive composition, the amount is about 0.03 to 2 parts by weight, preferably 0.05 to 2 parts by weight, based on 100 parts by weight of the acrylic copolymer (A). Degree. It is preferable that the amount of the silane compound with respect to 100 parts by weight of the acrylic copolymer is 0.03 parts by weight or more because adhesion between the pressure-sensitive adhesive layer and the glass substrate is improved. Moreover, it is preferable for the amount to be 2 parts by weight or less because the silane compound tends to be suppressed from bleeding out from the pressure-sensitive adhesive layer.

The pressure-sensitive adhesive described above may further contain a crosslinking catalyst, a weather resistance stabilizer, a tackifier, a plasticizer, a softener, a dye, a pigment, an inorganic filler, a resin other than the acrylic copolymer (A), and the like. . It is also useful to blend a UV curable compound with the pressure-sensitive adhesive and to cure it by irradiating it with ultraviolet light after forming the pressure-sensitive adhesive layer to form a harder pressure-sensitive adhesive layer. Especially, if a crosslinking catalyst is blended with the crosslinking agent in the pressure-sensitive adhesive, the pressure-sensitive adhesive layer can be prepared by aging in a short time, and in the obtained optical film with the pressure-sensitive adhesive, between the optical film and the pressure-sensitive adhesive layer. Occurrence of lifting or peeling or foaming in the pressure-sensitive adhesive layer can be suppressed, and reworkability can be further improved. Examples of the crosslinking catalyst include amine compounds such as hexamethylenediamine, ethylenediamine, polyethyleneimine, hexamethylenetetramine, diethylenetriamine, triethylenetetramine, isophoronediamine, trimethylenediamine, polyamino resin, and melamine resin. When an amine compound is added to the adhesive as a crosslinking catalyst, an isocyanate compound is suitable as the crosslinking agent.

[Optical film with adhesive]
The optical film with a pressure-sensitive adhesive of the present invention is obtained by providing a pressure-sensitive adhesive layer formed of the above pressure-sensitive adhesive composition on at least one surface of an optical film. The optical film used here is a film having optical characteristics, and examples thereof include a polarizing plate and a retardation film.

A polarizing plate is an optical film having a function of emitting polarized light with respect to incident light such as natural light. The polarizing plate absorbs linearly polarized light having a vibration surface in a certain direction incident on the film surface and transmits linearly polarized light having a vibration surface perpendicular to the polarizing surface, and in a certain direction incident on the film surface. There are a polarization separation film having a property of reflecting linearly polarized light having a vibration surface and transmitting linearly polarized light having a vibration surface orthogonal thereto, an elliptically polarizing plate in which a polarizing plate and a retardation film described later are laminated. As a suitable specific example of a polarizing plate, particularly a linearly polarizing film (sometimes called a polarizer or a polarizer film), a dichroic dye such as iodine or a dichroic dye is added to a uniaxially stretched polyvinyl alcohol resin film. Are adsorbed and oriented.

A retardation film is an optical film exhibiting optical anisotropy, for example, polyvinyl alcohol, polycarbonate, polyester, polyarylate, polyimide, polyolefin, polycycloolefin, polystyrene, polysulfone, polyethersulfone, polyvinylidene fluoride. A stretched film obtained by stretching a polymer film composed of ride / polymethyl methacrylate, liquid crystal polyester, acetyl cellulose, saponified ethylene-vinyl acetate copolymer, polyvinyl chloride, etc. about 1.01 to 6 times. Can be mentioned. Among these, a polymer film obtained by uniaxially stretching or biaxially stretching a polyolefin film or a cycloolefin-based resin film is preferable. Although there exist what is called a uniaxial phase difference film, a wide viewing angle phase difference film, a low photoelasticity phase difference film, etc., it is applicable to all.

The cycloolefin resin is, for example, a thermoplastic resin having a cycloolefin monomer unit represented by norbornene, tetracyclododecene (also known as dimethanooctahydronaphthalene) or a derivative thereof. In addition to the ring-opened polymer of the present invention and the hydrogenated product of the ring-opened copolymer using two or more kinds of cycloolefins, addition copolymerization of cycloolefin with a chain olefin or an aromatic compound having a vinyl group It may be a coalescence. In addition, a polar group may be introduced.

Commercially available thermoplastic cycloolefin-based resins are, for example, produced by TOPAS ADVANCED POLYMERS GmbH in Germany, and sold in Japan by Polyplastics Co., Ltd. and by JSR Co., Ltd. "ARTON" (ARTON), "ZEONEX" (ZEONEX) and "ZEONOR" (ZEONOR) sold by Nippon Zeon Co., Ltd., "APEL" sold by Mitsui Chemicals, Inc. )

When forming such a cycloolefin-based resin into a film, a known film forming method such as a solvent casting method or a melt extrusion method is appropriately used for film formation. A formed cycloolefin-based resin film and a cycloolefin-based resin film further stretched and provided with a phase difference are also commercially available. For example, "Arton Film" sold by JSR Corporation, "Zeonor Film" sold by Nippon Zeon Corporation, "Essina" and "SCA40" sold by Sekisui Chemical Co., Ltd. (Both are trade names) and these can be used preferably.

When an adhesive layer is formed on an optical film including a retardation film and is bonded to glass via the adhesive layer, if the moisture permeability of the retardation film is small, moisture is difficult to escape from the adhesive layer, especially In many cases, it was disadvantageous in durability under high temperature conditions. On the other hand, in the optical film with a pressure sensitive adhesive according to the present invention, when an optical film including a retardation film is used as the optical film, the retardation film is heated to a temperature of 40 ° C. by a cup method defined in JIS Z 0208. Even when the moisture permeability measured at a relative humidity of 90% is as small as 300 g / (m ² · 24 hr) or less, excellent durability is exhibited. Examples of the resin film having low moisture permeability include a polyolefin film and a cycloolefin-based resin film as described above. These polyolefin films and cycloolefin-based resin films have a moisture permeability of approximately 300 g / (m ² · 24 hr) or less under conditions of a temperature of 40 ° C. and a relative humidity of 90%.

Also, a film that exhibits optical anisotropy by applying and orienting a liquid crystalline compound and a film that exhibits optical anisotropy by applying an inorganic layered compound can be used as the retardation film. Such retardation films include what are called temperature-compensated retardation films, and films with a twisted orientation of rod-like liquid crystals sold under the trade name “LC film” by Nippon Oil Corporation. Also, a film with a tilted orientation of a rod-shaped liquid crystal sold under the trade name “NH film” by Shin Nippon Oil Co., Ltd., and a disk-shaped liquid crystal sold under the trade name “WV film” by FUJIFILM Corporation. Is a film with a tilt orientation, a fully biaxially oriented film sold under the name “VAC film” by Sumitomo Chemical Co., Ltd., and also sold under the product name “new VAC film” by Sumitomo Chemical Co., Ltd. There are biaxially oriented films.

Furthermore, those obtained by attaching a protective film to these optical films can also be used as optical films. As the protective film, a transparent resin film is used, and as the transparent resin, for example, an acetyl cellulose resin typified by triacetyl cellulose or diacetyl cellulose, a methacrylic resin typified by polymethyl methacrylate, a polyester resin, or a polyolefin Resin, polycarbonate resin, polyether ether ketone resin, polysulfone resin and the like. The resin constituting the protective film may contain a UV absorber such as a salicylic acid ester compound, a benzophenone compound, a benzotriazole compound, a triazine compound, a cyanoacrylate compound, or a nickel complex compound. As the protective film, an acetyl cellulose resin film such as a triacetyl cellulose film is preferably used. The acetylcellulose-based resin film may be used as a retardation film by imparting an appropriate retardation or making it virtually non-oriented in both the in-plane and thickness directions.

Among the optical films described above, the linear polarizing plate is used in a state where a protective film is attached to one side or both sides of a polarizing film constituting the polarizing film, for example, a polarizing film made of polyvinyl alcohol resin. There are many. Moreover, although the above-mentioned elliptically polarizing plate is a laminate of a linearly polarizing plate and a retardation film, the linearly polarizing plate may also be in a state where a protective film is attached to one side or both sides of the polarizing film. Many. When the pressure-sensitive adhesive layer according to the present invention is formed on such an elliptically polarizing plate, the pressure-sensitive adhesive layer is usually formed on the retardation film side.

As described above, the optical film exhibiting a moisture permeability of approximately 300 g / (m ² · 24 hr) or less under the conditions of a temperature of 40 ° C. and a relative humidity of 90% is from the viewpoint of enhancing the durability of the pressure-sensitive adhesive layer provided therein. This is one of the preferred ones for applying the present invention. As a typical example, there is a polarizing plate in which a retardation film made of a cycloolefin resin is bonded to one side of the polarizing film described above, and an arbitrary protective film is bonded to the other side of the polarizing film. be able to. In this case, it is preferable that the weight average molecular weight of the acrylic copolymer (A) forming the pressure-sensitive adhesive layer is 1 million or more.

On the other hand, the optical film exhibiting a water vapor permeability larger than about 300 g / (m ² · 24 hr) under the conditions of a temperature of 40 ° C. and a relative humidity of 90% is another aspect, that is, an acrylic copolymer of the pressure-sensitive adhesive layer provided there. From the standpoint that good results can be obtained even when a coalescence having a small weight average molecular weight is used, it is one of preferred ones for applying the present invention. As a typical example, a polarizing film in which a protective film or retardation film made of an acetyl cellulose resin is bonded to one side of the polarizing film described above, and an arbitrary protective film is bonded to the other side of the polarizing film. A board can be mentioned. In this case, as described above, good results can be obtained even if the weight average molecular weight of the acrylic copolymer (A) forming the pressure-sensitive adhesive layer is lowered to about 500,000.

Moreover, in the optical film with an adhesive of the present invention, it is preferable that a release film is stuck on the surface of the adhesive layer to protect it temporarily until use. The release film used here is, for example, a film made of various resins such as polyethylene terephthalate, polybutylene terephthalate, polycarbonate, polyarylate, and a bonding surface such as a silicone treatment on the adhesive layer of the substrate. It can be one that has undergone mold processing.

An optical film with an adhesive is, for example, a method in which the adhesive composition described above is applied to the release film as described above to form an adhesive layer, and the optical film is laminated on the obtained adhesive layer. It can be produced by a method of forming a pressure-sensitive adhesive layer by applying a pressure-sensitive adhesive composition on an optical film, attaching a release film to the pressure-sensitive adhesive surface to protect it, and forming an optical film with a pressure-sensitive adhesive.

The thickness of the pressure-sensitive adhesive layer is not particularly limited, but it is usually preferably 30 μm or less, more preferably 10 μm or more, and further preferably 10 to 20 μm. When the thickness of the pressure-sensitive adhesive layer is 30 μm or less, the adhesiveness under high temperature and high humidity is improved, and there is a tendency that the possibility of floating or peeling between the glass substrate and the pressure-sensitive adhesive layer is reduced. Moreover, it is preferable because reworkability tends to be improved. Further, if the thickness of the optical film bonded to the thickness is 10 μm or more, even if the dimension of the optical film bonded thereto changes, the adhesive layer changes following the change in dimension. This is preferable because there is no difference between the brightness of the portion and white spots and color unevenness tend to be suppressed.

[Optical laminate]
The optical film with an adhesive of the present invention can be laminated on a glass substrate on the adhesive layer side to form an optical laminate. In order to laminate an optical film with an adhesive on a glass substrate to form an optical laminate, for example, the release film is peeled off from the optical film with an adhesive obtained as described above, and the exposed adhesive layer is removed from the surface of the glass substrate. You just have to stick together. Here, as a glass substrate, the glass substrate of a liquid crystal cell, the glass for glare-proof, the glass for sunglasses etc. can be mentioned, for example. Among them, an optical film with an adhesive (upper polarizing film) is laminated on the glass substrate on the front side (viewing side) of the liquid crystal cell, and another optical film with an adhesive (lower polarizing film) on the glass substrate on the rear side of the liquid crystal cell. ) Is preferable because it can be used as a liquid crystal display device. Examples of the material for the glass substrate include soda lime glass, low alkali glass, non-alkali glass and the like, and non-alkali glass is preferably used for the liquid crystal cell.

After sticking the optical film with adhesive on the glass substrate to make an optical laminate in this way, if there is any problem, peel the optical film from the glass substrate and paste a new optical film with adhesive. A so-called rework work may be required. When the optical film with the pressure-sensitive adhesive of the present invention performs such a rework operation, the pressure-sensitive adhesive layer is peeled off along with the optical film, and the surface of the glass substrate that has been in contact with the pressure-sensitive adhesive layer has fogging or adhesive residue. Since hardly occurs, it is easy to re-adhere the optical film with the adhesive to the glass substrate after peeling. That is, it is excellent in so-called reworkability.

The optical laminate of the present invention can be used as a liquid crystal cell of a liquid crystal display device. The liquid crystal display device formed from the optical laminate of the present invention includes, for example, a liquid crystal display for a personal computer including a notebook type, a desktop type, a PDA (Personal Digital Assistance), a television, an in-vehicle display, an electronic dictionary, and a digital camera. It can be used for digital video cameras, electronic desk calculators, watches, etc.

Hereinafter, the present invention will be described more specifically with reference to examples, but the present invention is not limited to these examples. In the examples, “parts” and “%” representing the amount used or content are based on weight unless otherwise specified. In the following examples, the (meth) acrylic acid ester (A-1) represented by the formula (I) is changed to “monomer (A-1)”, one olefinic double bond in the molecule and at least 1 The unsaturated monomer (A-2) having one aromatic ring is referred to as “monomer (A-2)”, and N-alkoxyalkyl (meth) acrylamide (A-3) represented by the above formula (II) is used. The “monomer (A-3)” and the unsaturated monomer (A-4) having a polar functional group are referred to as “monomer (A-4)”, respectively.

In the following examples, the weight average molecular weight and the number average molecular weight are measured by using four TSK gel XL manufactured by Tosoh Corporation as a column in the GPC apparatus and Shoko Tsusho Co., Ltd. manufactured by Showa Denko K.K. One “Shodex GPC KF-802” sold in the market is placed in series, 5 in total, using tetrahydrofuran as the eluent, sample concentration 5 mg / ml, sample introduction amount 100 μl, temperature 40 ° C., Standard polystyrene conversion was performed under the condition of a flow rate of 1 ml / min.

First, a polymerization example in which an acrylic copolymer (A) defined in the present invention and a comparative acrylic copolymer deviating from the regulations are shown.

Polymerization example 1
In a reaction vessel equipped with a cooling tube, a nitrogen introduction tube, a thermometer and a stirrer, 81.8 parts of ethyl acetate as a solvent, 68.4 parts of butyl acrylate as a monomer (A-1), and methyl acrylate 20 0.0 part, 2- (2-phenoxyethoxy) ethyl acrylate as monomer (A-2) 8.0 part, N- (methoxymethyl) acrylamide 2.0 as monomer (A-3) And a mixed solution of 1.0 part of 2-hydroxyethyl acrylate and 0.6 part of acrylic acid as the monomer (A-4), and the air in the apparatus is replaced with nitrogen gas to prevent oxygen. The internal temperature was raised to 55 ° C. while containing. Thereafter, a total amount of a solution prepared by dissolving 0.14 part of azobisisobutyronitrile (polymerization initiator) in 10 parts of ethyl acetate was added. The temperature is maintained at this temperature for 1 hour after the addition of the initiator, and then ethyl acetate is continuously added into the reaction vessel at an addition rate of 17.3 parts / hr while maintaining the internal temperature at 54 to 56 ° C. When the combined concentration reached 35%, the addition of ethyl acetate was stopped, and the temperature was kept at this temperature until 12 hours had passed since the start of the addition of ethyl acetate. Finally, ethyl acetate was added to adjust the concentration of the acrylic copolymer to 20% to prepare an ethyl acetate solution of the acrylic copolymer. The obtained acrylic copolymer had a polystyrene equivalent weight average molecular weight Mw by GPC of 1,460,000 and Mw / Mn of 3.7. This is referred to as an acrylic copolymer A.

Polymerization example 2
Of the monomer composition, the amount of butyl acrylate was changed to 69.4 parts, the amount of N- (methoxymethyl) acrylamide was changed to 1.0 part, and the others were the same as in Polymerization Example 1, and the acrylic copolymer was used. A combined ethyl acetate solution was prepared. The obtained acrylic copolymer had a polystyrene equivalent weight average molecular weight Mw by GPC of 151,000 and Mw / Mn of 3.8. This is designated as acrylic copolymer B.

Polymerization example 3
In the monomer composition, the amount of butyl acrylate was changed to 69.9 parts, the amount of N- (methoxymethyl) acrylamide was changed to 0.5 parts, and the others were the same as in Polymerization Example 1, and the acrylic copolymer was used. A combined ethyl acetate solution was prepared. The obtained acrylic copolymer had a weight-average molecular weight Mw in terms of polystyrene by GPC of 141,000 and Mw / Mn of 3.7. This is referred to as an acrylic copolymer C.

Polymerization example 4
In the monomer composition, the amount of butyl acrylate was changed to 70.1 parts, the amount of N- (methoxymethyl) acrylamide was changed to 0.3 parts, and the others were the same as in Polymerization Example 1, and the acrylic copolymer was used. A combined ethyl acetate solution was prepared. The obtained acrylic copolymer had a polystyrene equivalent weight average molecular weight Mw by GPC of 1.6 million and Mw / Mn of 4.7. This is referred to as an acrylic copolymer D.

Polymerization example 5
In the monomer composition, the amount of butyl acrylate was changed to 70.3 parts, the amount of N- (methoxymethyl) acrylamide was changed to 0.1 parts, and the others were the same as in Polymerization Example 1, and the acrylic copolymer was used. A combined ethyl acetate solution was prepared. The resulting acrylic copolymer had a polystyrene equivalent weight average molecular weight Mw by GPC of 1,660,000 and Mw / Mn of 4.4. This is designated as acrylic copolymer E.

Polymerization Example 6
Of the monomer composition, the amount of butyl acrylate was changed to 69.9 parts, and N- (butoxymethyl) acrylamide was used instead of N- (methoxymethyl) acrylamide as monomer (A-3). The amount was 0.5 parts, and the others were the same as in Polymerization Example 1 to prepare an ethyl acetate solution of an acrylic copolymer. The obtained acrylic copolymer had a polystyrene-reduced weight average molecular weight Mw by GPC of 153,000 and Mw / Mn of 3.8. This is referred to as an acrylic copolymer F.

Polymerization example 7
In the monomer composition, the amount of butyl acrylate was changed to 69.8 parts, and N- (butoxymethyl) acrylamide was used instead of N- (methoxymethyl) acrylamide as monomer (A-3). The amount was 0.6 parts, and the others were the same as in Polymerization Example 1 to prepare an ethyl acetate solution of an acrylic copolymer. The obtained acrylic copolymer had a weight average molecular weight Mw in terms of polystyrene by GPC of 1,480,000 and Mw / Mn of 4.8. This is referred to as an acrylic copolymer G.

Polymerization Example 8
Of the monomer composition, the amount of butyl acrylate was changed to 69.6 parts, and the amount of acrylic acid was changed to 0.8 parts. Was prepared. The resulting acrylic copolymer had a polystyrene equivalent weight average molecular weight Mw by GPC of 1,420,000 and Mw / Mn of 4.7. This is referred to as an acrylic copolymer H.

Polymerization example 9
In the monomer composition, the amount of butyl acrylate was changed to 70.1 parts, the amount of acrylic acid was changed to 0.3 parts, and the others were the same as in Polymerization Example 7, and an acrylic copolymer solution in ethyl acetate Was prepared.
The resulting acrylic copolymer had a polystyrene equivalent weight average molecular weight Mw of 13.38 million and Mw / Mn of 4.6 by GPC. This is referred to as an acrylic copolymer I.

Polymerization Example 10
Of the monomer composition, the amount of butyl acrylate was changed to 70.0 parts, and the amount of acrylic acid was changed to 0.4 parts. Was prepared.
The obtained acrylic copolymer had a polystyrene equivalent weight average molecular weight Mw by GPC of 1,370,000 and Mw / Mn of 4.2. This is designated as acrylic copolymer J.

Polymerization example 11
Among the monomer compositions, N- (isobutoxymethyl) acrylamide [also known as N- (2-methylpropoxymethyl) acrylamide] is used instead of N- (butoxymethyl) acrylamide as the monomer (A-3). The same amount (0.6 parts) was used, and an ethyl acetate solution of an acrylic copolymer was prepared in the same manner as in Polymerization Example 10. The obtained acrylic copolymer had a polystyrene-reduced weight average molecular weight Mw of 1,270,000 and Mw / Mn of 4.7 by GPC. This is referred to as an acrylic copolymer K.

Polymerization example 12 (for comparison)
A monomer (A-3) was not used, the amount of butyl acrylate was 70.4 parts, and the others were the same as in Polymerization Example 1 to prepare an ethyl acetate solution of an acrylic copolymer. The obtained acrylic copolymer had a polystyrene-reduced weight average molecular weight Mw of 1,580,000 and Mw / Mn of 4.8 by GPC. This is referred to as an acrylic copolymer W.

Polymerization Example 13 (for comparison)
The monomer composition was changed to 98.6 parts of butyl acrylate, 1.0 part of 2-hydroxyethyl acrylate, and 0.4 part of acrylic acid. An ethyl acetate solution was prepared. The obtained acrylic copolymer had a polystyrene equivalent weight average molecular weight Mw by GPC of 1,230,000 and Mw / Mn of 3.9. This is referred to as an acrylic copolymer X.

Table 1 summarizes the monomer compositions in the above polymerization examples 1 to 13, the weight average molecular weight of the obtained acrylic copolymer, and Mw / Mn. In the table, the symbols in the column of monomer composition mean the following monomers, respectively.

(A-1)
BA: butyl acrylate,
MA: methyl acrylate,
(A-2)
PEA2: 2- (2-phenoxyethoxy) ethyl acrylate,
(A-3)
MMAM: N- (methoxymethyl) acrylamide,
BMAM: N- (butoxymethyl) acrylamide,
IBMAM: N- (isobutoxymethyl) acrylamide [also known as N- (2-methylpropoxymethyl) acrylamide],
(A-4)
HEA: 2-hydroxyethyl acrylate
AA: Acrylic acid.

Next, examples and comparative examples in which an adhesive was prepared using the acrylic copolymer produced above and applied to an optical film are shown. In the following examples, the following were used as the ionic compound, the crosslinking agent, and the silane compound, respectively. The first name of the crosslinking agent and silane compound is the trade name.

<Ionic compounds>
N-octyl-4-methylpyridinium hexafluorophosphate (having the structure of the following formula, melting point: 44 ° C.).

<Crosslinking agent>
Coronate L: Trimethylolpropane adduct of tolylene diisocyanate in ethyl acetate solution (solid content: 75%), obtained from Nippon Polyurethane Co., Ltd.

<Silane compounds>
KBM-403: 3-glycidoxypropyltrimethoxysilane, liquid, obtained from Shin-Etsu Chemical Co., Ltd.

[Examples 1 to 13 and Comparative Examples 1 and 2]
(A) Production of pressure-sensitive adhesive Using a 20% ethyl acetate solution of the acrylic copolymer prepared in Polymerization Examples 1 to 13, an ionic compound and a crosslinking agent “Coronate L” were added to 100 parts of each solid content. The amount shown in Table 2 and 0.5 part of the silane compound “KBM-403” were mixed, and ethyl acetate was further added so that the solid content concentration was 13% to obtain a pressure-sensitive adhesive composition. As described above, the cross-linking agent “Coronate L” is an ethyl acetate solution having a solid concentration of 75%, but the addition amount shown in Table 2 is the amount of the solid content (active ingredient).

(B) Production of optical film with pressure-sensitive adhesive Each of the above pressure-sensitive adhesive compositions was released from a release-treated polyethylene terephthalate film (trade name “PLR-382050”, obtained from Lintec Corporation; called a separator). It apply | coated so that the thickness after drying might be set to 20 micrometers using an applicator on the process surface, and it dried for 1 minute at 100 degreeC, and obtained the sheet-like adhesive. Next, a protective film having a thickness of 80 μm made of triacetylcellulose is laminated on one side of a polarizing film in which iodine is adsorbed and oriented on polyvinyl alcohol, and a retardation film having a thickness of 70 μm made of a cycloolefin resin on the other side. [The moisture permeability at a temperature of 40 ° C. and a relative humidity of 90% is 42 g / (m ² · 24 hr)] laminated on the cycloolefin-based resin film surface of the three-layer polarizing plate, The surface opposite to the separator (adhesive surface) was bonded with a laminator, and then cured for 7 days under the conditions of a temperature of 23 ° C. and a relative humidity of 65% to prepare a polarizing plate with an adhesive.

(C) Antistatic property evaluation of optical film with adhesive The separator was peeled from the obtained polarizing plate with adhesive, and the surface resistance value of the adhesive layer exposed after peeling was measured using a surface resistivity measuring device [Mitsubishi Chemical Corporation ) Manufactured by “Hirest-up MCP-HT450” (trade name)] to evaluate the antistatic property. If the surface resistance value is on the order of 10 ¹¹ Ω / □ or less, good antistatic properties can be obtained. The antistatic property was evaluated immediately after the curing of the polarizing plate with an adhesive was completed. The results are summarized in the “surface resistance value” column of Table 2.

(D) Preparation of optical laminate and durability evaluation After the separator was peeled off from the polarizing plate with the adhesive prepared in (b) above, the adhesive surface was placed on a glass substrate for a liquid crystal cell [“EAGLE XG” manufactured by Corning. (Product name)] was pasted on both sides so as to be crossed Nicols, and an optical laminate was produced. The following four types of durability tests were performed on this optical laminate.

(1) Moisture and heat resistance test stored at a temperature of 60 ° C. and a relative humidity of 90% for 300 hours,
(2) 80 ° C. heat resistance test stored for 300 hours under dry conditions at a temperature of 80 ° C.
(3) 100 ° C. heat resistance test stored for 300 hours under dry conditions at a temperature of 100 ° C.,
(4) A heat shock resistance test in which the temperature is lowered to −30 ° C. from the state heated to 70 ° C. and then raised to 70 ° C. as one cycle (1 hour), and this is repeated 100 cycles.

The optical laminates after each test were visually observed, the appearance changes were classified according to the following criteria, and the results were summarized in the “Durability” column of Table 2. In Table 2, “HS resistance” means heat shock resistance.

<Evaluation criteria for durability test>
A: No change in appearance such as floating, peeling or foaming is observed.
○: Almost no change in appearance such as floating, peeling or foaming.
Δ: Appearance changes such as floating, peeling and foaming are slightly noticeable.
X: Remarkable changes in appearance such as floating, peeling, foaming, etc.

(E) Reworkability evaluation of optical film with adhesive The reworkability was evaluated as follows. First, the polarizing plate with an adhesive produced in the above (b) was cut into a test piece having a size of 25 mm × 150 mm. Next, the test piece was attached to the glass substrate for a liquid crystal cell on the pressure-sensitive adhesive side using a sticking apparatus ["Lami Packer" (trade name) manufactured by Fuji Plastics Co., Ltd.], temperature 50 ° C., pressure 5 kg / cm. ² (490.3 kPa) was autoclaved for 20 minutes. Next, after heat-treating at 70 ° C. for 2 hours and subsequently holding in an oven at 50 ° C. for 48 hours, the polarizing plate is attached together with the pressure-sensitive adhesive layer from the adhesion test piece in an atmosphere at a temperature of 23 ° C. and a relative humidity of 50%. A peel test for peeling in a 180 ° direction (direction folded and along the glass substrate surface) at a speed of 300 mm / min was performed, and the state of the glass substrate surface after peeling was observed and classified according to the following criteria. The results are summarized in the column of “Reworkability” in Table 2.

<Evaluation criteria for reworkability>
A: No fogging or the like is observed on the glass substrate surface.
A: Almost no fogging or the like is observed on the glass substrate surface.
Δ: Clouding or the like is observed on the glass substrate surface.
X: The remainder of an adhesive is recognized by the glass substrate surface.

As can be seen from Tables 1 and 2, the acrylic copolymer (A) defined in the present invention is mixed with a predetermined amount of an ionic compound and a crosslinking agent to form a pressure-sensitive adhesive composition, which is then formed. Examples 1 to 13 in which the pressure-sensitive adhesive layer was provided on the polarizing plate exhibited high durability in any of wet heat conditions, 80 ° C. drying conditions, 100 ° C. drying conditions, and heat shock conditions, as well as antistatic properties and rework. In terms of sex, almost satisfactory results were obtained.

On the other hand, Comparative Examples 1 and 2 using an acrylic copolymer in which the monomer (A-3) is not copolymerized are insufficient in heat resistance at 100 ° C.

Next, a polymerization example in which a plurality of acrylic copolymers different from the acrylic copolymers described in Table 1 were synthesized, and another example and comparative example in which an adhesive was prepared using them and applied to an optical film Indicates. In the following examples and comparative examples, the same ionic compound, crosslinking agent and silane compound as those shown above were used.

Polymerization Example 14
Into a reaction vessel equipped with a cooling pipe, a nitrogen introduction pipe, a thermometer and a stirrer, 120 parts of ethyl acetate as a solvent was charged, and the air in the apparatus was replaced with nitrogen gas to make it oxygen-free. Raised to ° C. After adding a total amount of a solution in which 0.05 part of azobisisobutyronitrile (polymerization initiator) was dissolved in 5 parts of ethyl acetate, while maintaining the internal temperature at 74 to 76 ° C., the monomer (A-1) was used. 68.6 parts of butyl acrylate and 20.0 parts of methyl acrylate, 8.0 parts of 2- (2-phenoxyethoxy) ethyl acrylate as monomer (A-2), monomer (A-3) ) N- (butoxymethyl) acrylamide 0.6 part, and a mixed solution of 2-hydroxyethyl acrylate 2.0 part and acrylic acid 0.8 part as monomer (A-4) The solution was dropped into the reaction system over time. Furthermore, the reaction was completed by incubating at an internal temperature of 74 to 76 ° C. for 5 hours. Finally, ethyl acetate was added to adjust the concentration of the acrylic copolymer to 40% to prepare an ethyl acetate solution of the acrylic copolymer. The obtained acrylic copolymer had a polystyrene equivalent weight average molecular weight Mw by GPC of 680,000 and Mw / Mn of 4.9. This is referred to as an acrylic copolymer L.

Polymerization Example 15
The amount of ethyl acetate as a solvent was 140 parts, the amount of azobisisobutyronitrile as a polymerization initiator was 0.07 parts, and the others were the same as in Polymerization Example 14 to prepare an ethyl acetate solution of an acrylic copolymer. Prepared. The obtained acrylic copolymer had a polystyrene equivalent weight average molecular weight Mw by GPC of 500,000 and Mw / Mn of 4.2. This is referred to as an acrylic copolymer M.

Polymerization Example 16 (for comparison)
A monomer (A-3) was not used, the amount of butyl acrylate was 69.2 parts, and the others were the same as in Polymerization Example 14 to prepare an ethyl acetate solution of an acrylic copolymer. The obtained acrylic copolymer had a polystyrene equivalent weight average molecular weight Mw by GPC of 650,000 and Mw / Mn of 4.5. This is referred to as an acrylic copolymer Y.

Polymerization Example 17 (for comparison)
A monomer (A-3) was not used, the amount of butyl acrylate was 69.2 parts, and the others were the same as in Polymerization Example 15 to prepare an ethyl acetate solution of an acrylic copolymer. The resulting acrylic copolymer had a polystyrene equivalent weight average molecular weight Mw of 510,000 and Mw / Mn of 4.2 by GPC. This is referred to as an acrylic copolymer Z.

Table 3 summarizes the monomer compositions in the above Polymerization Examples 14 to 17, the weight average molecular weight of the obtained acrylic copolymer, and the list of Mw / Mn. In the table, the meanings of symbols in the column of monomer composition are the same as those in Table 1.

[Examples 14 to 17 and Comparative Examples 3 to 6]
(A) Production of pressure-sensitive adhesive Using the 40% ethyl acetate solution of the acrylic copolymer prepared in Polymerization Examples 14 to 17, an ionic compound and a crosslinking agent “Coronate L” were added to 100 parts of each solid content. The amount shown in Table 4 (crosslinking agent “Coronate L” is solid amount) and 0.5 part of silane compound “KBM-403” are mixed, and ethyl acetate is added so that the solid concentration is 29%. Thus, an adhesive composition was prepared.

(B) Production of optical film with pressure-sensitive adhesive Each of the above pressure-sensitive adhesive compositions was released from a release-treated polyethylene terephthalate film (trade name “PLR-382050”, obtained from Lintec Corporation; called a separator). It apply | coated so that the thickness after drying might be set to 20 micrometers using an applicator on the process surface, and it dried for 1 minute at 100 degreeC, and obtained the sheet-like adhesive. Next, a protective film having a thickness of 80 μm made of triacetyl cellulose is laminated on one side of a polarizing film in which iodine is adsorbed and oriented on polyvinyl alcohol, and a retardation film having a thickness of 41 μm made of triacetyl cellulose is formed on the other side. After laminating the surface (adhesive surface) opposite to the separator of the sheet-like adhesive obtained above on the 41 μm thick triacetyl cellulose surface of the laminated three-layer polarizing plate, the temperature was 23 Curing was performed for 7 days under the conditions of ° C. and relative humidity of 65% to prepare a polarizing plate with an adhesive.

(C) Evaluation of antistatic property of optical film with adhesive For the obtained polarizing plate with adhesive, the surface resistance value of the adhesive layer was measured by the same method as shown in Examples 1 to 13 (c). The results are summarized in the column “Surface Resistance” in Table 4.

(D) Production of optical laminate and durability evaluation The polarizing plate with the adhesive produced in (b) above was subjected to a durability test by the same method as shown in (d) of Examples 1 to 13, and the result Were classified according to the same criteria as in Table 2, and are summarized in the column of “Durability” in Table 4.

(E) Reworkability evaluation of optical film with pressure-sensitive adhesive About the polarizing plate with pressure-sensitive adhesive prepared in (b) above, reworkability is evaluated by the same method as shown in (e) of Examples 1 to 13, The results were classified according to the same criteria as in Table 2 above, and summarized in the “Reworkability” column of Table 4.

As can be seen from Tables 3 and 4, the acrylic copolymer (A) defined in the present invention is ionic even when the weight average molecular weight shows a relatively small value of 500,000 to 1,000,000. By applying a predetermined amount of each of the compound and the crosslinking agent to constitute a pressure-sensitive adhesive composition, and applying it as a pressure-sensitive adhesive layer to the triacetyl cellulose surface of the polarizing plate having triacetyl cellulose as a protective film as the protective film, High durability was given under any of moist heat conditions, 80 ° C. drying conditions, 100 ° C. drying conditions, and heat shock conditions, and antistatic properties and reworkability were almost satisfactory.

On the other hand, Comparative Examples 3 to 6 using an acrylic copolymer in which the monomer (A-3) is not copolymerized lack damp heat resistance and 100 ° C. heat resistance. The results were also unsatisfactory in terms of heat resistance or heat shock resistance. Further, Comparative Example 5 in which the monomer (A-3) was not copolymerized, the acrylic copolymer Z having a low weight average molecular weight of about 500,000, and the blending amount of the crosslinking agent was small, was reworked. In FIG. 1, the remaining adhesive was observed on the glass surface.

The optical film with pressure-sensitive adhesive of the present invention is imparted with high antistatic properties and, when bonded to glass through a pressure-sensitive adhesive layer, is durable in a harsh environment assuming vehicle use, etc. Excellent durability at high temperatures of around 100 ° C. This optical film with an adhesive is suitably used for a liquid crystal display device.

Claims (10)

1. An optical film with an adhesive comprising an optical film and an adhesive layer formed on at least one side thereof,
   The pressure-sensitive adhesive layer comprises 100 parts by weight of an acrylic copolymer (A), 0.3 to 12 parts by weight of an ionic compound (B) having an organic cation, and 0.1 to 5 parts by weight of a crosslinking agent (C ) Containing a pressure-sensitive adhesive composition,
   The acrylic copolymer (A) is 80 to 96% by weight of (A-1), 1 to 15% by weight of (A-2), 0.1 to 5% by weight of (A-3), and Obtained from a monomer mixture containing 0.5 to 5% by weight of (A-4),
   (A-1) represents the following formula (I)
   

   

   (Wherein R ₁ represents a hydrogen atom or a methyl group, and R ₂ represents an alkyl group having 1 to 14 carbon atoms which may be substituted with an alkoxy group having 1 to 10 carbon atoms)
   (Meth) acrylic acid ester represented by
   (A-2) is an unsaturated monomer having one olefinic double bond and at least one aromatic ring in the molecule;
   (A-3) is represented by the following formula (II)
   

   

   (Wherein R ₃ represents a hydrogen atom or a methyl group, R ₄ represents an alkyl group, and m represents an integer of 1 to 8)
   N-alkoxyalkyl (meth) acrylamide represented by
   (A-4) is an unsaturated monomer having a polar functional group.
2. The unsaturated monomer (A-2) having an aromatic ring is represented by the following formula (III)
   

   

   (Wherein R ₅ represents a hydrogen atom or a methyl group, n represents an integer of 1 to 8, and R ₆ represents a hydrogen atom, an alkyl group, an aralkyl group, or an aryl group)
   The optical film with a pressure-sensitive adhesive according to claim 1, which is a (meth) acrylic compound containing a phenoxyethyl group represented by formula (1).
3. In the formula (II) representing the N-alkoxyalkyl (meth) acrylamide (A-3), R ₄ is an alkyl group having 1 to 6 carbon atoms, and m is an integer of 1 to 4. 2. An optical film with an adhesive according to 2.
4. The N-alkoxyalkyl (meth) acrylamide (A-3) is
   N- (methoxymethyl) acrylamide,
   N- (ethoxymethyl) acrylamide,
   N- (propoxymethyl) acrylamide,
   N- (1-methylethoxymethyl) acrylamide,
   N- (1-methylpropoxymethyl) acrylamide,
   N- (2-methylpropoxymethyl) acrylamide,
   N- (butoxymethyl) acrylamide,
   N- (1,1-dimethylethoxymethyl) acrylamide,
   N- (2-methoxyethyl) acrylamide,
   N- (2-ethoxyethyl) acrylamide,
   N- (2-propoxyethyl) acrylamide,
   N- [2- (1-methylethoxy) ethyl] acrylamide,
   N- [2- (1-methylpropoxy) ethyl] acrylamide,
   N- [2- (2-methylpropoxy) ethyl] acrylamide,
   The optical film with an adhesive according to claim 3, which is N- (2-butoxyethyl) acrylamide or N- [2- (1,1-dimethylethoxy) ethyl] acrylamide.
5. The unsaturated monomer (A-4) having a polar functional group has a polar functional group selected from the group consisting of a free carboxyl group, a hydroxyl group, an amino group, and an epoxy ring. The optical film with an adhesive as described.
6. The optical film with an adhesive according to any one of claims 1 to 5, wherein the crosslinking agent (C) contains an isocyanate compound.
7. The pressure-sensitive adhesive composition further comprises 0.03 to 2 parts by weight of the silane compound (D) with respect to 100 parts by weight of the acrylic copolymer (A). Optical film with adhesive.
8. The optical film with an adhesive according to any one of claims 1 to 7, wherein the optical film is selected from the group consisting of a polarizing plate and a retardation film.
9. The optical film with an adhesive according to any one of claims 1 to 8, wherein a release film is adhered to the surface of the adhesive layer.
10. An optical laminate comprising a glass substrate and an optical film with an adhesive according to any one of claims 1 to 8, which is laminated on the glass substrate on the adhesive layer side.