JP5587645B2 - Optical pressure-sensitive adhesive, optical pressure-sensitive adhesive sheet, and optical member with a pressure-sensitive adhesive layer - Google Patents

Description

  The present invention relates to an optical pressure-sensitive adhesive, an optical pressure-sensitive adhesive sheet, and an optical member with a pressure-sensitive adhesive layer. More specifically, the present invention has an antistatic property used when laminating an optical member such as a polarizing plate on an adherend, and has good adhesive force, removability (reworkability), and durability. And an optical pressure-sensitive adhesive having anti-bleeding anti-bleeding properties, an optical pressure-sensitive adhesive sheet with a release film, and a layer made of the optical pressure-sensitive adhesive layer provided on an optical member such as a polarizing plate. The present invention relates to an attached optical member.

Optical members such as a polarizing plate, a retardation plate, an optical compensation film, a reflection sheet, and a brightness enhancement film used for a liquid crystal display are bonded to a liquid crystal cell or the like via an adhesive layer.
In a liquid crystal cell, generally, two transparent electrode substrates on which an alignment layer is formed are arranged so that a predetermined gap is provided by a spacer with the alignment layer inside, and a liquid crystal material is sealed in the gap. In addition, the polarizing plate is disposed on the outer surface of each of the two transparent electrode substrates via an adhesive layer.

FIG. 1 is a perspective view showing a configuration of an example of the polarizing plate. As shown in this figure, the polarizing plate 10 generally has a three-layer structure in which triacetyl cellulose (TAC) films 2 and 2 ′ are bonded to both surfaces of a polyvinyl alcohol polarizer 1. And the adhesive layer 3 for sticking to optical components, such as a liquid crystal cell, is formed in the single side | surface, Furthermore, the peeling sheet 4 is stuck to this adhesive layer 3. FIG. Moreover, the surface protective film 5 is normally provided in the surface on the opposite side to this adhesive layer 3 of this polarizing plate.
When sticking such a polarizing plate to the liquid crystal cell, first, the release sheet 4 is peeled off, attached to the liquid crystal cell via the exposed adhesive layer 3, and then the surface protective film 5 is peeled off.
When the release sheet 4 and the surface protective film 5 are peeled off, these sheets, film, and polarizing plate are made of a plastic material, so that the electrical insulation is high and static electricity is generated. If pasting is performed on the liquid crystal cell in a state where the static electricity generated at this time remains, the alignment of the liquid crystal molecules may be disturbed. The disorder of the alignment of the liquid crystal molecules generated in this way may not be recovered, and even in the case of recovery, in the liquid crystal display manufacturing process, the process does not proceed to the next process until recovery. Problems that cause delays have been pointed out. In addition, the presence of static electricity causes problems such as sucking dust and dirt.

In order to cope with such a problem, measures such as kneading an antistatic agent into the base material of the release sheet have been conventionally taken, but such a measure alone cannot provide a sufficient effect, and an adhesive. It is also required to impart antistatic performance to the layer.
As an adhesive composition having antistatic performance, an adhesive composition containing an antistatic agent such as a surfactant is known. Thus, when an antistatic agent such as a surfactant is added to the adhesive composition, the antistatic performance is imparted, but the compatibility between the surfactant and the adhesive polymer is poor. When the layer is formed, the surfactant bleeds over time or under heat or wet heat conditions, causing problems such as contamination of the adherend or reduced adhesive strength.

On the other hand, for the purpose of improving the compatibility between the antistatic agent and the pressure-sensitive adhesive polymer, an antistatic pressure-sensitive adhesive containing an organic salt having a polyoxyalkylene structure as an antistatic agent is disclosed (for example, , See Patent Document 1).
However, the organic salt having the polyoxyalkylene structure is still not sufficient with respect to the compatibility with the acrylic polymer mainly used for sticking a polarizing plate, etc. The organic salt may bleed and peel off. In addition, when organic salts are used, there is a problem that odor may remain.

Further, in the pressure-sensitive adhesive composition comprising a (meth) acrylic polymer mainly comprising a (meth) acrylic monomer having an alkyl group having 6 to 14 carbon atoms, a polyether polyol compound and an alkali metal salt, A pressure-sensitive adhesive composition comprising a meth) acrylic polymer having an acid value of 1.0 or less and containing less than 0.1 part by weight of the alkali metal salt with respect to 100 parts by weight of the (meth) acrylic polymer is disclosed. (For example, refer to Patent Document 2).
However, this pressure-sensitive adhesive composition uses a combination of a polyether polyol compound and an alkali metal salt as a conductive agent, and can sufficiently satisfy all of anti-peeling property, adhesion and durability. It is not a thing.

As an optical pressure-sensitive adhesive imparted with antistatic performance, those capable of forming a pressure-sensitive adhesive layer having a surface resistivity of about 5 × 10 ¹⁰ Ω / □ or less are generally required.
On the other hand, a polarizing plate that is a member of a liquid crystal display, in particular, a polarizing plate integrated with a viewing angle widening film and the like, a bonding of a liquid crystal cell, a polarizing plate and a retardation plate, a mutual bonding and a retardation plate In the bonding of the phase difference plate and the liquid crystal cell, “durability” that does not cause peeling even under various environments, and resistance to light leakage caused by dimensional changes such as shrinkage and expansion of the film There is a demand for an optical pressure-sensitive adhesive sheet having a pressure-sensitive adhesive layer (hereinafter referred to as “light leakage resistance”) (see, for example, Patent Document 3).
However, an optical pressure-sensitive adhesive that forms a pressure-sensitive adhesive layer having sufficient durability and light leakage resistance while having an excellent antistatic property with a surface resistivity of about 5 × 10 ¹⁰ Ω / □ or less is provided. The actual situation has not been found.

As a prior document relevant to the present invention, for example, a pressure-sensitive adhesive composition containing a (meth) acrylic polymer having an alkylene oxide group-containing reactive monomer as a monomer component and an alkali metal salt (for example, Patent Document 4) And a pressure-sensitive adhesive composition in which a lithium salt is contained in two types of polymers having different glass transition temperatures is disclosed (see, for example, Patent Document 5).
Any of the pressure-sensitive adhesive compositions has a composition in which many hydrophilic monomers are used as monomers constituting the polymer in order to exhibit antistatic properties. Therefore, as a surface protective film that is finally peeled off and discarded, it is considered that the pressure-sensitive adhesive layer formed by the pressure-sensitive adhesive composition disclosed above has sufficient performance, but the liquid crystal display as in the present invention. In the case of forming a part of the structure, durability and light leakage resistance are expected to be problems.

  As a prior document closest to the present invention, Patent Document 6 has been proposed. In Patent Document 6, an acrylic copolymer obtained by copolymerizing a hydroxyl group-containing monomer, an acrylic copolymer obtained by copolymerizing acrylic acid, And a pressure-sensitive adhesive composition containing various antistatic agents in a pressure-sensitive adhesive composition containing a polyfunctional acrylate monomer.

Special Table 2004-536940 JP 2005-325255 A Japanese Patent No. 3272721 (Japanese Patent Laid-Open No. 9-87593) JP 2007-92056 A JP 2008-248223 A JP 2008-32852 A

The pressure-sensitive adhesive layer formed by the pressure-sensitive adhesive composition disclosed in Patent Document 6 has certain antistatic properties while having durability and light leakage resistance. However, in the pressure-sensitive adhesive composition of this document, the addition of various antistatic agents was examined, but after having sufficient durability and light leakage resistance, the surface resistivity was excellent at about 5 × 10 ¹⁰ Ω / □ or less. It has not yet achieved antistatic properties.
The present invention has been made under such circumstances, and has an antistatic performance with a surface resistivity of about 5 × 10 ¹⁰ Ω / □ or less, which is used when an optical member such as a polarizing plate is laminated on an adherend. Optical adhesive with excellent adhesive strength, re-peelability, light leakage resistance and durability and anti-bleeding anti-bleeding property (non-precipitating property), and a release film using the same It is an object to provide an optical pressure-sensitive adhesive sheet and an optical member with a pressure-sensitive adhesive layer.

As a result of intensive studies to achieve the above object, the present inventors have obtained (A) a specific amount of an oxyalkylene group-containing (meth) acrylic monomer and a specific amount of a reactive group-containing (meth) acrylic monomer. And a (meth) acrylic acid ester copolymer having (meth) acrylic acid alkyl ester as a structural unit, and (B) a (meth) acrylic acid ester copolymer having a reactive group-containing (meth) acrylic monomer as a structural unit , (C) an active energy ray-curable compound, and (D) an antistatic agent, and the pressure-sensitive adhesive forming material in which the content ratio of the component (A) and the component (B) is in a specific range is crosslinked. It has been found that the purpose can be achieved by the pressure-sensitive adhesive.
The present invention has been completed based on such findings.

That is, the present invention
[1] (A) (a-1) Oxyalkylene group-containing (meth) acrylic monomer 5 to 90 mass% and (a-2) Reactive group-containing (meth) acrylic monomer 0.1 mass% or more 10 (Meth) acrylic acid ester copolymer having less than mass% and (a-3) (meth) acrylic acid alkyl ester as structural units, (B) (b-1) reactive group-containing (meth) acrylic (Meth) acrylate copolymer having 5 to 20% by mass of monomer and (b-2) 80 to 95% by mass of (meth) acrylic acid alkyl ester having no reactive group as structural units, (C) It contains a polyfunctional (meth) acrylate monomer having a molecular weight of less than 1000 , and (D) an antistatic agent, and the content ratio of the component (A) and the component (B) is 100: 1 to 100: 50 adhesive forming material Optical adhesive characterized by comprising by measles,
[2] The content of the (C) polyfunctional (meth) acrylate monomer having a molecular weight of less than 1000 is 1 to 50 parts by mass with respect to 100 parts by mass of the total amount of the component (A) and the component (B). The optical pressure-sensitive adhesive according to item [1],
[3] (a-1) In the above (1), in the (meth) acrylic monomer containing an oxyalkylene group, the oxyalkylene group has 2 to 4 carbon atoms and the oxyalkylene group has 1 to 10 carbon atoms. Or the optical pressure-sensitive adhesive according to item [2],
[4] The optical pressure-sensitive adhesive according to any one of [1] to [3] above, wherein the (a-2) reactive group-containing (meth) acrylic monomer is a hydroxyl group-containing (meth) acrylic monomer,
[5] The reactive group-containing (meth) acrylic monomer that is a constituent unit of the component (b-1) is a carboxyl group-containing (meth) acrylic monomer, according to any one of [1] to [4] above. The optical pressure-sensitive adhesive as described,
[6] The content of the (D) antistatic agent is 0.1 to 10 parts by mass with respect to 100 parts by mass of the total amount of the component (A), the component (B), and the component (C) [ 1]-[5] optical adhesive according to any one of items
[7] The optical pressure-sensitive adhesive according to any one of items [1] to [6], wherein the pressure-sensitive adhesive-forming material further contains (E) a crosslinking agent,
[8] An optical pressure-sensitive adhesive sheet with a release film formed using the optical pressure-sensitive adhesive according to any one of [1] to [7] above,
[9] An optical member with an adhesive layer having a layer made of the optical adhesive according to any one of [1] to [7] above on the optical member, and [10] The optical member is a polarizing plate. The optical member with the pressure-sensitive adhesive layer according to the above [9],
Is to provide.

Moreover, as a preferred embodiment of the present invention,
(A) The optical pressure-sensitive adhesive wherein the (C) active energy ray-curable compound is a polyfunctional (meth) acrylate monomer,
(B) The (D) antistatic agent has the general formula (1)
(Z ^{a +} ) _m · (A ^b− ) _n (1)
[ ^Wherein , Z ^{a +} represents a cation and A ^b− represents an anion, and a, b, m and n are each an integer of 1 to 3, and satisfy the relationship of a × m = b × n. If Z a ⁺ there are multiple, ⁺ the plurality of Z ^a may be the same or different, if the A ^b-there are multiple, ^b-multiple A may be the same or different. ]
An optical pressure-sensitive adhesive containing a solid or liquid ionic compound represented by:
(C) The pressure-sensitive adhesive forming material further includes an optical pressure-sensitive adhesive containing a silane coupling agent,
(D) The optical pressure-sensitive adhesive in which the (E) crosslinking agent is an isocyanate-based crosslinking agent,
(E) The optical pressure-sensitive adhesive wherein the (a-1) oxyalkylene group-containing (meth) acrylic monomer is 2- (methoxy) ethyl acrylate or ethyl carbitol acrylate,
(F) An optical pressure-sensitive adhesive that performs crosslinking of the pressure-sensitive adhesive-forming material by heat treatment and active energy ray irradiation treatment,
(G) A pressure-sensitive adhesive sheet formed by sandwiching an optical pressure-sensitive adhesive so that the optical pressure-sensitive adhesive sheet with a release film is in contact with the release layer side of two release films;
Can be mentioned.

According to the present invention, it has an antistatic performance with a surface resistivity of about 5 × 10 ¹⁰ Ω / □ or less, which is used when an optical member such as a polarizing plate is laminated on an adherend, and has a good adhesive force. Optical adhesive with re-peelability, light leakage resistance and durability, and anti-bleeding anti-bleeding property (non-precipitating property), optical adhesive with release film using the optical adhesive The optical member with an adhesive layer formed by providing a sheet and a layer made of the above optical adhesive on an optical member such as a polarizing plate can be provided.

It is a perspective view which shows the structure of one example of a polarizing plate. It is explanatory drawing which shows the method of evaluating the light leak resistance of the polarizing plate with an adhesive layer obtained by the Example and the comparative example.

First, the optical pressure-sensitive adhesive of the present invention will be described.
The optical pressure-sensitive adhesive of the present invention has (A) a (meth) acrylic acid ester copolymer having the following components as structural units, and (B) a reactive group-containing (meth) acrylic monomer as a structural unit. (Meth) acrylic acid ester copolymer, (C) active energy ray-curable compound, and (D) antistatic agent, and the content ratio of the component (A) and the component (B) is a mass ratio. The pressure-sensitive adhesive forming material of 100: 1 to 100: 50 is crosslinked.

[Adhesive forming material]
The pressure-sensitive adhesive forming material used in the optical pressure-sensitive adhesive of the present invention has (A) the following component (a-1), component (a-2), and component (a-3) as structural units ( (Meth) acrylic acid ester copolymer, (B) (meth) acrylic acid ester copolymer having a reactive group-containing (meth) acrylic monomer as a structural unit, (C) active energy ray-curable compound, (D) Contains an antistatic agent and (E) a crosslinking agent used as required. In addition, the active energy ray in said (C) active energy ray hardening-type compound refers to what has an energy quantum in electromagnetic waves or a charged particle beam, ie, an ultraviolet-ray, an electron beam, etc.

((A) (meth) acrylic acid ester copolymer)
(A) component (A) component (A) component (A-1) in the pressure-sensitive adhesive forming material is (a-1) oxyalkylene group-containing (meth) acrylic monomer 5 to 90% by mass, and (a-2) reaction. And (a-3) (meth) acrylic acid alkyl ester as essential constituent units.
In the present invention, (meth) acrylic acid ester means both acrylic acid ester and methacrylic acid ester. The same applies to other similar terms.
The optical pressure-sensitive adhesive of the present invention has an antistatic performance with a surface resistivity of about 5 × 10 ¹⁰ Ω / □ or less, which is used when an optical member such as a polarizing plate is laminated on an adherend, and is favorable. In order to obtain an adhesive that has adhesive strength, re-peelability, light leakage resistance and durability, and also has anti-bleeding (non-precipitating) antistatic agent, (A) component (meth) acrylic The acid ester copolymer requires the (a-1) component, the (a-2) component, and the (a-3) component as essential structural units.

The (meth) acrylic acid ester copolymer of component (A) preferably has a weight average molecular weight of 1 million or more. When this weight average molecular weight is less than 1,000,000, the adhesion durability under high temperature and high humidity becomes insufficient, which may cause floating or peeling. In view of adhesion durability and the like, the weight average molecular weight is more preferably 1,200,000 to 2,200,000, and particularly preferably 1,300,000 to 2,000,000. Further, the molecular weight distribution (Mw / Mn) representing the ratio of the weight average molecular weight (Mw) to the number average molecular weight (Mn) is preferably 20 or less. When the molecular weight distribution is 20 or less, sufficient adhesion durability can be obtained.
In addition, the said weight average molecular weight and number average molecular weight are the values of polystyrene conversion measured by the gel permeation chromatography (GPC) method.

<(A-1) Oxyalkylene group-containing (meth) acrylic monomer>
In the (meth) acrylic acid ester copolymer of the component (A), the (a-1) oxyalkylene group-containing (meth) acrylic monomer component introduced as an essential constituent unit has durability and rework under wet heat conditions. This contributes to improving the antistatic property without lowering the property.
Usually, in order for the antistatic agent to exert its function in the adhesive, it is necessary to stabilize the ionization state of the antistatic agent. For this reason, it is designed to assist the ionization state of the antistatic agent by introducing a hydroxyl group or a carboxyl group into the main polymer. However, in order to obtain an antistatic property with a surface resistivity of 5 × 10 ¹⁰ Ω / □ or less, if the content of the hydroxyl group in the main polymer is increased, the hydrophilicity of the pressure-sensitive adhesive is increased so Durability deteriorates. Moreover, if the content of the carboxyl group in the polymer is increased, the reworkability is deteriorated. On the other hand, when the component (a-1) is introduced as in the present invention, the ionization state of the antistatic agent can be further stabilized without causing the problem of increased content of hydroxyl groups or carboxyl groups. Furthermore, the oxygen atom of the oxyalkylene group derived from the monomer acts weakly with the antistatic agent, thereby forming an environment in which a cationic species such as Li ⁺ can freely move in a state of being ionized in the adhesive. Contribute. Therefore, the function can be exhibited more effectively than when the function of the antistatic agent is exhibited only with a hydroxyl group or a carboxyl group as a functional group in the main polymer.
The (a-1) oxyalkylene group-containing (meth) acrylic monomer component preferably has 2 to 4 carbon atoms. The oxyalkylene group having 2 to 4 carbon atoms may be either linear or branched, and specifically includes an oxyethylene group, an oxypropylene group (branched), an oxytrimethylene group, and an oxybutylene group. (Branched), oxytetramethylene group and the like can be mentioned.
The number of oxyalkylene groups is 1 or more, and the upper limit thereof is preferably about 10 in order to obtain the (meth) acrylic acid ester copolymer of the component (A) having the above-mentioned weight average molecular weight. Is more preferable, and about 3 is more preferable. The oxyalkylene group is preferably an alkyloxyalkylene group. Furthermore, the alkyl of the alkyloxyalkylene group preferably has 1 to 14 carbon atoms from the viewpoint of not impairing the antistatic property of the pressure-sensitive adhesive. Furthermore, it is especially preferable that it is a C1-C4 alkyl from the same viewpoint. Considering the above, from the viewpoint of the performance of the optical pressure-sensitive adhesive of the present invention described above, the (a-1) oxyalkylene group-containing (meth) acrylic monomer may be 2- (methoxy) ethyl acrylate or ethyl carbitol. Acrylate is preferred.
In this (a-1) oxyalkylene group-containing (meth) acrylic monomer unit, one kind may be introduced, or two or more kinds may be introduced, in the (meth) acrylic acid ester copolymer. The content of is required to be 5 to 90% by mass, preferably 10 to 50% by mass, more preferably 15 to 25% by mass, from the viewpoint of the performance of the optical pressure-sensitive adhesive of the present invention described above. .

<(A-2) Reactive group-containing (meth) acrylic monomer>
In the (meth) acrylic acid ester copolymer of the component (A), the reactive group in the (a-2) reactive group-containing (meth) acrylic monomer component introduced as an essential constituent unit is an adhesive-forming material. A hydroxyl group, a carboxyl group, an amino group, an epoxy group, and the like can be mentioned because it is a functional group that serves as a crosslinking point at the time of crosslinking. In the present invention, a hydroxyl group is preferred.
Specific examples of the hydroxyl group-containing (meth) acrylic monomer in the component (a-2) include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, and 3-hydroxy (meth) acrylate. And (meth) acrylic acid hydroxyalkyl esters such as propyl, 2-hydroxybutyl (meth) acrylate, 3-hydroxybutyl (meth) acrylate, and 4-hydroxybutyl (meth) acrylate. These may be used singly or may be used in combination of two or more, among which 2-hydroxyethyl (meth) acrylate and 4-hydroxybutyl (meth) acrylate are particularly weight average molecular weights. One or more (A) (meth) acrylic acid ester copolymers are preferred because they can be easily produced.
In the (meth) acrylic acid ester copolymer of the component (A), the content of the (a-2) reactive group-containing (meth) acrylic monomer unit is determined by imparting antistatic properties to the resulting adhesive and wet heat conditions. From the viewpoint of durability below, it needs to be less than 10% by mass and is preferably 0.1% by mass or more. Furthermore, from the viewpoint of the reworkability of the resulting pressure-sensitive adhesive, the content of the reactive group-containing (meth) acrylic monomer unit is particularly preferably 1 to 5% by mass.

<(A-3) (Meth) acrylic acid alkyl ester>
In the (meth) acrylic acid ester copolymer of the component (A), the (a-3) (meth) acrylic acid alkyl ester component introduced as an essential constituent unit is not particularly limited. Preferable examples include (meth) acrylic acid esters having a group having 1 to 20 carbon atoms. Here, examples of the (meth) acrylic acid ester having 1 to 20 carbon atoms of the alkyl group in the ester portion include methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, (meth ) Butyl acrylate, pentyl (meth) acrylate, hexyl (meth) acrylate, cyclohexyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, isooctyl (meth) acrylate, decyl (meth) acrylate, Examples include dodecyl (meth) acrylate, myristyl (meth) acrylate, palmityl (meth) acrylate, stearyl (meth) acrylate, and the like. These may be used alone or in combination of two or more.
Among these compounds, in particular, butyl (meth) acrylate can obtain an appropriate adhesive performance, and can easily produce a (meth) acrylic acid ester copolymer having a weight average molecular weight of 1 million or more. Is preferable. In addition, content of (a-3) (meth) acrylic-acid alkylester as a structural component in (A) (meth) acrylic acid ester copolymer is the said component (a-1) and component (a-2). However, it is usually 0.1% by mass or more. From the viewpoint of increasing compatibility with (B) (meth) acrylic acid ester copolymer and (C) active energy ray-curable compound, the content is preferably 40 to 89.9% by mass, and 70 to 70%. It is especially preferable that it is 84 mass%.

((B) (meth) acrylic acid ester copolymer)
The (meth) acrylic acid ester copolymer of the component (B) in the pressure-sensitive adhesive forming material has a weight average molecular weight of 1 million or more, like the (meth) acrylic acid ester copolymer of the component (A) described above. Preferably there is. When this weight average molecular weight is less than 1,000,000, the adhesion durability under high temperature and high humidity becomes insufficient, which may cause floating or peeling. In view of adhesion durability and the like, the weight average molecular weight is more preferably 1,200,000 to 2,200,000, and particularly preferably 1,300,000 to 2,000,000. Further, the molecular weight distribution (Mw / Mn) representing the ratio of the weight average molecular weight (Mw) to the number average molecular weight (Mn) is preferably 20 or less. When the molecular weight distribution is 20 or less, sufficient adhesion durability can be obtained.
In addition, the said weight average molecular weight and number average molecular weight are the values of polystyrene conversion measured by the gel permeation chromatography (GPC) method.
The (B) component (meth) acrylic acid ester copolymer has a reactive group-containing (meth) acrylic monomer component (hereinafter sometimes referred to as (b-1)) as an essential constituent unit. In the copolymer, the reactive group is a functional group that becomes a cross-linking point when the pressure-sensitive adhesive-forming material is cross-linked, and examples thereof include a hydroxyl group, a carboxyl group, an amino group, and an epoxy group. However, in the present invention, a carboxyl group is preferable.
Specific examples of the carboxyl group-containing monomer in the component (B) include (meth) acrylic acid, crotonic acid, maleic acid, itaconic acid, citraconic acid and the like. These may be used singly or in combination of two or more, among which a (meth) acrylic acid ester copolymer having a weight average molecular weight of 1 million or more can be easily produced. From the viewpoint, (meth) acrylic acid is preferable.

The (meth) acrylic acid ester copolymer of component (B) usually comprises a (meth) acrylic acid alkyl ester component (hereinafter sometimes referred to as (b-2)) that does not have a reactive group. As a unit.
(B-2) The (meth) acrylic acid alkyl ester having no reactive group is not particularly limited and is the same as that used in the component (a-3), that is, the carbon of the alkyl group in the ester moiety. Preference is given to (meth) acrylic acid esters having a number of 1 to 20. These may be used alone or in combination of two or more.
Among these compounds, as in the case of the component (a-3), in particular, butyl (meth) acrylate can obtain an appropriate adhesive performance, and the component (B) having a weight average molecular weight of 1 million or more. It is preferable at the point which can manufacture a (meth) acrylic acid ester polymer easily.

  The content of the carboxyl group-containing monomer component in the (meth) acrylic acid ester copolymer of the component (B) is preferably 5 to 20% by mass. If the content exceeds 20% by mass, the adhesive strength with the liquid crystal cell may increase, and the removability (reworkability) may be impaired. On the other hand, if the content is less than 5% by mass, the durability at high temperatures may be impaired. It tends to decline. From such a viewpoint, the content is more preferably 5 to 15% by mass. In addition, it is preferable that content of the (b-2) component as a structural component is 80-95 mass%, and it is especially preferable that it is 85-95 mass%.

  In the pressure-sensitive adhesive forming material, the content ratio of the (meth) acrylic acid ester copolymer of the component (A) and the (meth) acrylic acid ester copolymer of the component (B) described above is obtained for optical use. From the viewpoint of the performance of the pressure-sensitive adhesive, it is necessary that the mass ratio is 100: 1 to 100: 50, preferably 100: 2.5 to 100: 30, and 100: 5 to 100: 20. Is more preferable.

((C) active energy ray-curable compound)
As the active energy ray-curable compound of the component (C) in the pressure-sensitive adhesive forming material, a polyfunctional (meth) acrylate monomer having a molecular weight of less than 1000 can be preferably exemplified.
Examples of the polyfunctional (meth) acrylate monomer having a molecular weight of less than 1000 include 1,4-butanediol di (meth) acrylate, 1,6-hexanediol di (meth) acrylate, neopentyl glycol di (meth) acrylate, Polyethylene glycol di (meth) acrylate, neopentyl glycol adipate di (meth) acrylate, hydroxypivalate neopentyl glycol di (meth) acrylate, dicyclopentanyl di (meth) acrylate, caprolactone modified dicyclopentenyl di (meth) acrylate , Ethylene oxide modified di (meth) acrylate phosphate, di (acryloxyethyl) isocyanurate, allylated cyclohexyl di (meth) acrylate, dimethylol dicyclopentane di (meth) acrylate, ethylene oxide modified hydride Lophthalic acid di (meth) acrylate, tricyclodecane dimethanol (meth) acrylate, neopentyl glycol modified trimethylolpropane di (meth) acrylate, adamantane di (meth) acrylate, 9,9-bis [4- (2-acryloyl) Bifunctional types such as oxyethoxy) phenyl] fluorene; trimethylolpropane tri (meth) acrylate, dipentaerythritol tri (meth) acrylate, propionic acid modified dipentaerythritol tri (meth) acrylate, pentaerythritol tri (meth) acrylate, Trifunctional type such as propylene oxide modified trimethylolpropane tri (meth) acrylate, tris (acryloxyethyl) isocyanurate; diglycerin tetra (meth) acrylate, pentaerythritol tetra (meth) acrylate Any tetrafunctional type; pentafunctional type such as propionic acid-modified dipentaerythritol penta (meth) acrylate; hexafunctional type such as dipentaerythritol hexa (meth) acrylate and caprolactone-modified dipentaerythritol hexa (meth) acrylate .

  In the present invention, these polyfunctional (meth) acrylate monomers may be used alone or in combination of two or more. Among these, a skeleton structure has a cyclic structure. It is preferable to contain what it has. The cyclic structure may be a carbocyclic structure or a heterocyclic structure, and may be a monocyclic structure or a polycyclic structure. Examples of such polyfunctional (meth) acrylate monomers include those having an isocyanurate structure such as di (acryloxyethyl) isocyanurate, tris (acryloxyethyl) isocyanurate, dimethylol dicyclopentane diacrylate, ethylene Oxide-modified hexahydrophthalic acid diacrylate, tricyclodecane dimethanol acrylate, neopentyl glycol-modified trimethylolpropane diacrylate, adamantane diacrylate, and the like are suitable.

  Further, an active energy ray-curable acrylate oligomer can be used as the component (C). Examples of such acrylate oligomers include polyester acrylate, epoxy acrylate, urethane acrylate, polyether acrylate, polybutadiene acrylate, and silicone acrylate.

Here, as the polyester acrylate oligomer, for example, by esterifying hydroxyl groups of a polyester oligomer having hydroxyl groups at both ends obtained by condensation of a polyvalent carboxylic acid and a polyhydric alcohol with (meth) acrylic acid, It can be obtained by esterifying the terminal hydroxyl group of an oligomer obtained by adding alkylene oxide to a carboxylic acid with (meth) acrylic acid. The epoxy acrylate oligomer can be obtained, for example, by reacting (meth) acrylic acid with an oxirane ring of a relatively low molecular weight bisphenol type epoxy resin or novolak type epoxy resin and esterifying it. A carboxyl-modified epoxy acrylate oligomer obtained by partially modifying this epoxy acrylate oligomer with a dibasic carboxylic acid anhydride can also be used. The urethane acrylate oligomer can be obtained, for example, by esterifying a polyurethane oligomer obtained by reaction of polyether polyol or polyester polyol with polyisocyanate with (meth) acrylic acid. It can be obtained by esterifying the hydroxyl group of ether polyol with (meth) acrylic acid.
The weight average molecular weight of the acrylate oligomer is a standard polymethyl methacrylate conversion value measured by GPC method, preferably 50,000 or less, more preferably 1,000 to 50,000, and still more preferably 3,000 to 40. It is selected in the range of 1,000.
These acrylate oligomers may be used alone or in combination of two or more.

In the present invention, an adduct acrylate polymer in which a group having a (meth) acryloyl group is introduced into the side chain can also be used as the component (C). Such an adduct acrylate polymer has a (meth) acrylic acid alkyl ester described in the (meth) acrylic acid ester copolymer of the component (A) and a crosslinkable functional group that is a reactive group in the molecule. Using a copolymer with a monomer having a monomer, and reacting a compound having a group capable of reacting with a (meth) acryloyl group and a crosslinkable functional group on a part of the crosslinkable functional group of the copolymer. Can do. The weight average molecular weight of the adduct acrylate polymer is usually 500,000 to 2,000,000 in terms of polystyrene.
In the present invention, as the component (C), one type may be appropriately selected from the above polyfunctional acrylate monomers, acrylate oligomers, and adduct acrylate polymers, or two or more types may be used in combination. A polyfunctional (meth) acrylate monomer having a molecular weight of less than 1000 is preferable.

  Content of the said (C) active energy ray hardening-type compound in the said adhesive forming material is 100 mass of total amounts of the (A) component and (B) component mentioned above from a viewpoint of the performance of the optical adhesive obtained. The amount is preferably 1 to 50 parts by mass, more preferably 2 to 30 parts by mass, and still more preferably 4 to 25 parts by mass with respect to parts.

((D) antistatic agent)
In the pressure-sensitive adhesive forming material, an antistatic agent is used as the component (D) in order to impart antistatic performance with a surface resistivity of about 5 × 10 ¹⁰ Ω / □ or less to the obtained optical pressure-sensitive adhesive. .
There is no restriction | limiting in particular as this antistatic agent, It can select suitably from well-known antistatic agents currently used in order to provide antistatic performance to the optical adhesive. For example, what contains an ionic compound can be used.

<Ionic compounds>
As an ionic compound, for example, the general formula (1)
(Z ^{a +} ) _m · (A ^b− ) _n (1)
[ ^Wherein , Z ^{a +} represents a cation and A ^b− represents an anion, and a, b, m and n are each an integer of 1 to 3, and satisfy the relationship of a × m = b × n. If Z a ⁺ there are multiple, ⁺ the plurality of Z ^a may be the same or different, if the A ^b-there are multiple, ^b-multiple A may be the same or different. ]
The compound represented by these can be mentioned.
The ionic compound may be either solid or liquid, and the cation represented by Za ⁺ may be an inorganic cation or an organic cation.

≪Cation represented by Z ^{a +} ≫
In the cation represented by Z ^{a +} in the general formula (1), examples of the inorganic cation include, for example, alkali metal cations such as Li ⁺ , Na ⁺ and K ⁺ . From the viewpoint of imparting excellent antistatic performance, Li ⁺ or K ⁺ is particularly preferable.

On the other hand, examples of the organic cation include the following cations.
Examples thereof include a pyridinium cation, a piperidinium cation, a pyrrolidinium cation, a cation having a pyrroline skeleton, and a cation having a pyrrole skeleton. Specific examples include 1-ethylpyridinium cation, 1-butylpyridinium cation, 1-hexylpyridinium cation, 1-butyl-3-methylpyridinium cation, 1-butyl-4-methylpyridinium cation, 1-hexyl-3. -Methylpyridinium cation, 1-butyl-3,4-dimethylpyridinium cation, 1-octyl-4-methylpyridinium cation, 1,1-dimethylpyrrolidinium cation, 1-ethyl-1-methylpyrrolidinium cation, 1 -Methyl-1-propylpyrrolidinium cation, 2-methyl-1-pyrroline cation, 1-ethyl-2-phenylindole cation, 1,2-dimethylindole cation, 1-ethylcarbazole cation and the like.

  For example, imidazolium cation, tetrahydropyrimidinium cation, dihydropyrimidinium cation and the like can be mentioned. Specific examples include 1,3-dimethylimidazolium cation, 1,3-diethylimidazolium cation, 1-ethyl-3-methylimidazolium cation, 1-butyl-3-methylimidazolium cation, 1-hexyl- 3-methylimidazolium cation, 1-octyl-3-methylimidazolium cation, 1-decyl-3-methylimidazolium cation, 1-dodecyl-3-methylimidazolium cation, 1-tetradecyl-3-methylimidazolium cation 1,2-dimethyl-3-propylimidazolium cation, 1-ethyl-2,3-dimethylimidazolium cation, 1-butyl-2,3-dimethylimidazolium cation, 1-hexyl-2,3-dimethyl Imidazolium cation, 1,3-dimethyl-1,4,5,6-teto Lahydropyrimidinium cation, 1,2,3-trimethyl-1,4,5,6-tetrahydropyrimidinium cation, 1,2,3,4-tetramethyl-1,4,5,6-tetrahydropyri Midinium cation, 1,2,3,5-tetramethyl-1,4,5,6-tetrahydropyrimidinium cation, 1,3-dimethyl-1,4-dihydropyrimidinium cation, 1,3-dimethyl 1,6-dihydropyrimidinium cation, 1,2,3-trimethyl-1,4-dihydropyrimidinium cation, 1,2,3-trimethyl-1,6-dihydropyrimidinium cation, 1,2 1,3,4-tetramethyl-1,4-dihydropyrimidinium cation, 1,2,3,4-tetramethyl-1,6-dihydropyrimidinium cation, and the like.

  For example, a pyrazolium cation, a pyrazolinium cation, etc. are mentioned. Specific examples include 1-methylpyrazolium cation, 3-methylpyrazolium cation, 1-ethyl-2-methylpyrazolinium cation and the like.

  Examples thereof include a tetraalkylammonium cation, a trialkylsulfonium cation, a tetraalkylphosphonium cation, and those in which a part of the alkyl group is substituted with an alkenyl group, an alkoxyl group, or an epoxy group. Specific examples include tetramethylammonium cation, tetraethylammonium cation, tetrabutylammonium cation, tetrahexylammonium cation, triethylmethylammonium cation, tributylethylammonium cation, trimethylhexylammonium cation, trimethyldecylammonium cation, N, N-diethyl- N-methyl-N- (2-methoxyethyl) ammonium cation, glycidyltrimethylammonium cation, N, N-dimethyl-N, N-dipropylammonium cation, N, N-dimethyl-N, N-dihexylammonium cation, N , N-dipropyl-N, N-dihexylammonium cation, trimethylsulfonium cation, triethylsulfonium cation, tributyl Rufonium cation, trihexylsulfonium cation, diethylmethylsulfonium cation, dibutylethylsulfonium cation, dimethyldecylsulfonium cation, tetramethylphosphonium cation, tetraethylphosphonium cation, tetrabutylphosphonium cation, tetrahexylphosphonium cation, triethylmethylphosphonium cation, tributylethyl Examples thereof include a phosphonium cation, a trimethyldecylphosphonium cation, and a diallyldimethylammonium cation.

≪Anion represented by A ^b- ≫
On the other hand, in the general formula (1), the anion represented by A ^b- is not particularly limited as long as it can ionically bond with the cation to form an ionic compound. For example, F ⁻ , Cl ⁻ , Br ⁻ , I ⁻ , AlCl ₄ ⁻ , Al ₂ Cl ₇ ⁻ , BF ₄ ⁻ , PF ₆ ⁻ , SCN ⁻ , ClO ₄ ⁻ , NO ₃ ⁻ , CH ₃ COO ⁻ , CF ₃ COO ⁻ , CH ₃ SO ₃ ⁻ , CF ₃ SO ₃ ⁻ , (CF ₃ SO ₂ ) ₂ N ⁻ , (F ₂ SO ₂ ) ₂ N ⁻ , (CF ₃ SO ₂ ) ₃ C ⁻ , AsF ₆ ⁻ , SbF ₆ ⁻ , NbF ₆ ⁻ , TaF ₆ ⁻ , F (HF) _n ⁻ , (CN) ₂ N ⁻ , C ₄ F ₉ SO ₃ ⁻ , (C ₂ F ₅ SO ₂ ) ₂ N ⁻ , C ₃ F ₇ COO ⁻ , (CF ₃ SO ₂ ) (CF ₃ CO) N ^- or the like is used. Among these, an anion containing a fluorine atom is preferable because it gives an ionic compound having a low melting point, and (F ₂ SO ₂ ) ₂ N ⁻ or (CF ₃ SO ₂ ) ₂ N ⁻ is particularly preferable.

When the cation represented by Z ^{a +} is Li ⁺ , examples of the ionic compound include LiBr, LiI, LiBF ₄ , LiPF ₆ , LiSCN, LiClO ₄ , LiCF ₃ SO ₃ , Li (CF ₃ SO ₂ ) ₂ N , Li (F ₂ SO ₂ ) ₂ N, Li (CF ₃ SO ₂ ) ₃ C, and further compounds such as lithium octylbenzenesulfonate, lithium dodecylbenzenesulfonate, lithium dibutylnaphthalenesulfonate, Among these, Li (CF ₃ SO ₂ ) ₂ N [lithium bis (trifluoromethanesulfonyl) imide], Li (CF ₃ SO ₂ ) ₃ C [lithium tris (trifluoromethanesulfonyl) methane], or Li (F ₂ SO ₂ ) ₂ N [Lithium bis (difluorosulfonyl) imide] is preferred.
When the cation represented by Z ^{a +} is K ⁺ , the ionic compound may be K (F ₂ SO ₂ ) ₂ N [potassium bis (difluorosulfonyl) imide] or K (CF ₃ SO ₂ ) _2. N [potassium bis (trifluoromethanesulfonyl) imide] is preferred.
When the cation represented by Z ^{a +} is a pyridinium cation, examples of the ionic compound include 1-ethylpyridinium hexafluorophosphate, 1-butylpyridinium hexafluorophosphate, 1-hexyl-4-methylpyridinium hexafluorophosphate. 1-octyl-4-methylpyridinium hexafluorophosphate and the like are preferable.
The ionic compound represented by the general formula (1) may be used alone or in combination of two or more.

（式中、Ｒは水素原子又はメチル基を示す。）
で表される化合物などを挙げることができる。
本発明においては、この四級アンモニウム塩基含有モノマーは１種用いてもよいし、２種以上を組み合わせて用いてもよく、また、前述したイオン性化合物と併用してもよい。
この四級アンモニウム塩基含有モノマーを、当該粘着剤形成材料中に含有させることにより、活性エネルギー線を照射して架橋化を行う際に、該材料中に存在する活性エネルギー線硬化型化合物と、前記四級アンモニウム塩基含有モノマーとが共重合し、得られた光学用粘着剤中に四級アンモニウム塩基が導入され、帯電防止性能が付与される。 A reactive quaternary ammonium base-containing compound is also preferably exemplified as an example satisfying the general formula (1).
<Reactive quaternary ammonium base-containing compound>
Examples of the reactive quaternary ammonium base-containing compound include, for example, the general formula (2)

(In the formula, R represents a hydrogen atom or a methyl group.)
The compound etc. which are represented by these can be mentioned.
In this invention, this quaternary ammonium base containing monomer may be used 1 type, may be used in combination of 2 or more type, and may be used together with the ionic compound mentioned above.
By including this quaternary ammonium base-containing monomer in the pressure-sensitive adhesive-forming material, when performing crosslinking by irradiating active energy rays, the active energy ray-curable compound present in the material, and A quaternary ammonium base-containing monomer is copolymerized, and a quaternary ammonium base is introduced into the resulting optical pressure-sensitive adhesive to impart antistatic performance.

The content of the antistatic agent as component (D) in the pressure-sensitive adhesive forming material depends on the type of antistatic agent, but the surface resistivity of the obtained optical pressure-sensitive adhesive is 5 × 10 ¹⁰ Ω / □ or less. The antistatic agent is imparted with a degree of antistatic performance, and from the viewpoint of bleeding prevention and precipitation prevention of the antistatic agent, with respect to a total of 100 parts by mass of the components (A), (B) and (C) described above In general, it is about 0.1 to 10 parts by mass, preferably 0.5 to 5 parts by mass, and more preferably 0.5 to 3 parts by mass.

In the pressure-sensitive adhesive forming material, as an optional component, (E) a crosslinking agent, a silane coupling agent, a photopolymerization initiator, and various additives such as an antioxidant, an ultraviolet absorber, and a light stabilizer, as necessary. An agent, a leveling agent, an antifoaming agent, etc. can be contained.
((E) Crosslinking agent)
The pressure-sensitive adhesive forming material can contain a crosslinking agent as the component (E) as necessary. There is no restriction | limiting in particular as this crosslinking agent, Arbitrary things can be suitably selected and used from what was conventionally used as a crosslinking agent in an acrylic adhesive. Examples of such crosslinking agents include polyisocyanate compounds, epoxy resins, melamine resins, urea resins, dialdehydes, methylol polymers, aziridine compounds, metal chelate compounds, metal alkoxides, and metal salts. A compound is preferably used.

  Here, examples of the polyisocyanate compound include aromatic polyisocyanates such as tolylene diisocyanate, diphenylmethane diisocyanate, and xylylene diisocyanate, aliphatic polyisocyanates such as hexamethylene diisocyanate, alicyclic polyisocyanates such as isophorone diisocyanate, and hydrogenated diphenylmethane diisocyanate. And their biurets, isocyanurates, and adducts that are reaction products with low-molecular active hydrogen-containing compounds such as ethylene glycol, propylene glycol, neopentyl glycol, trimethylol propane, castor oil, etc. Can do.

  In this invention, this crosslinking agent may be used individually by 1 type, and may be used in combination of 2 or more type. The amount used depends on the type of the crosslinking agent, but is usually 0.01 to 20 parts by mass, preferably 0 with respect to 100 parts by mass of the total amount of the components (A) and (B). 0.1 to 10 parts by mass.

(Silane coupling agent)
When the optical adhesive such as a polarizing plate is bonded to a glass cell or the like by using the obtained optical adhesive by including a silane coupling agent as necessary in the adhesive forming material, The adhesion between the pressure-sensitive adhesive and the glass cell becomes better. This silane coupling agent is an organosilicon compound having at least one alkoxysilyl group in the molecule, having good compatibility with the pressure-sensitive adhesive component, and having light transparency, for example, substantially transparent Is preferred. The addition amount of such a silane coupling agent is preferably in the range of 0.001 to 10 parts by mass with respect to 100 parts by mass of the total amount of the component (A), the component (B) and the component (C). A range of 0.005 to 5 parts by mass is preferred.

  Specific examples of the silane coupling agent include polymerizable unsaturated group-containing silicon compounds such as vinyltrimethoxysilane, vinyltriethoxysilane, methacryloxypropyltrimethoxysilane, 3-glycidoxypropyltrimethoxysilane, 2- Silicon compounds having an epoxy structure such as (3,4-epoxycyclohexyl) ethyltrimethoxysilane, 3-aminopropyltrimethoxysilane, N- (2-aminoethyl) -3-aminopropyltrimethoxysilane, N- (2 -Aminoethyl) -3-aminopropylmethyldimethoxysilane and other amino group-containing silicon compounds, 3-chloropropyltrimethoxysilane and the like. These may be used individually by 1 type and may be used in combination of 2 or more type.

(Photopolymerization initiator)
When the adhesive forming material is irradiated with an active energy ray such as ultraviolet rays to crosslink the active energy ray-curable compound (C) contained therein, photopolymerization is started as necessary. An agent can be included. In addition, when using an electron beam as an active energy ray, it is not necessary to use a photoinitiator.
Examples of this photopolymerization initiator include benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzoin-n-butyl ether, benzoin isobutyl ether, acetophenone, dimethylaminoacetophenone, 2,2-dimethoxy-2-phenylacetophenone, 2,2-diethoxy-2-phenylacetophenone, 2-hydroxy-2-methyl-1-phenylpropan-1-one, 1-hydroxycyclohexyl phenyl ketone, 2-methyl-1- [4- (methylthio) phenyl]- 2-morpholino-propan-1-one, 4- (2-hydroxyethoxy) phenyl-2- (hydroxy-2-propyl) ketone, benzophenone, p-phenylbenzophenone, 4,4′-diethylaminobenzopheno Dichlorobenzophenone, 2-methylanthraquinone, 2-ethylanthraquinone, 2-tert-butylanthraquinone, 2-aminoanthraquinone, 2-methylthioxanthone, 2-ethylthioxanthone, 2-chlorothioxanthone, 2,4-dimethylthioxanthone, 2, 4-diethylthioxanthone, benzyldimethyl ketal, acetophenone dimethyl ketal, p-dimethylaminobenzoate, oligo [2-hydroxy-2-methyl-1- [4- (1-methylvinyl) phenyl] propanone], 2,4 1,6-trimethylbenzoyl-diphenyl-phosphine oxide and the like. These may be used individually by 1 type, may be used in combination of 2 or more type, and the compounding quantity is 0.2 to 100 mass parts of all active energy ray hardening-type compounds normally. 20 parts by mass, preferably 1 to 15 parts by mass.

(Preparation of coating solution containing adhesive forming material)
There is no particular limitation on the method for preparing the coating liquid containing the pressure-sensitive adhesive forming material. For example, in the solvent, the (meth) acrylic acid ester copolymer of the component (A) described above and the (meth) acrylic of the component (B) It contains an acid ester copolymer, an active energy ray curable compound of component (C), and an antistatic agent of component (D), and is used as necessary. A crosslinking agent and / or silane coupling of component (E) Add the adhesive, photopolymerization initiator, and various additives such as antioxidants, UV absorbers, light stabilizers, leveling agents, antifoaming agents, etc. A working solution can be prepared.
Examples of the solvent include aliphatic hydrocarbons such as hexane and heptane, aromatic hydrocarbons such as toluene and xylene, halogenated hydrocarbons such as methylene chloride and ethylene chloride, alcohols such as methanol, ethanol, propanol, and butanol, acetone. , Ketones such as methyl ethyl ketone, 2-pentanone, isophorone and cyclohexanone, esters such as ethyl acetate and butyl acetate, cellosolv solvents such as ethyl cellosolve, glycol ether solvents such as propylene glycol monomethyl ether, and the like. These solvents may be used alone or in a combination of two or more.
The concentration of the adhesive material in the coating solution is not particularly limited as long as the coating solution has a viscosity suitable for coating.

[Optical pressure sensitive adhesive]
The optical pressure-sensitive adhesive of the present invention is coated on a substrate such as a release film or an optical member by a conventionally known method using the coating liquid containing the pressure-sensitive adhesive forming material obtained as described above. And the layer which consists of an optical adhesive of this invention can be formed by bridge | crosslinking.
For this crosslinking, the wet coating film provided on the adherend is heat-treated at a temperature of about 40 to 150 ° C. for about 10 seconds to 10 minutes, whereby the crosslinking agent (E) and (A The crosslinkable functional group in the (meth) acrylic acid ester copolymer of the component (B) and the crosslinkable functional group in the (meth) acrylic acid ester copolymer of the component (B) react with each other to effect crosslinking.
On the other hand, the active energy ray-curable compound in the coating film is crosslinked by irradiating the coating film on the adherend that has been heat-treated in this way and partially crosslinked with active energy rays. Occur.
When ultraviolet rays are used as the active energy rays, the ultraviolet rays are obtained by a high pressure mercury lamp, an electrodeless lamp, a xenon lamp or the like, while the electron beam is obtained by an electron beam accelerator or the like. Among these active energy rays, ultraviolet rays are particularly preferable. In addition, when using an electron beam, an adhesive can be formed, without adding a photoinitiator.
The irradiation amount of the active energy ray with respect to the pressure-sensitive adhesive forming material is appropriately selected so as to obtain a pressure-sensitive adhesive having a suitable storage elastic modulus and adhesion to non-alkali glass. In the case of 1000 mW / cm ² , light quantity 50 to 1000 mJ / cm ² , and electron beam, a range of 10 to 1000 krad is preferable.

Next, the optical adhesive sheet with a release film of the present invention will be described.
[Optical adhesive sheet with release film]
The optical pressure-sensitive adhesive sheet with a release film of the present invention is an optical pressure-sensitive adhesive sheet with a release film formed using the optical pressure-sensitive adhesive of the present invention described above.
Specific examples of this optical adhesive sheet with a release film include an optical adhesive sheet in which the optical adhesive of the present invention described above is sandwiched so as to be in contact with the release layer side of two release films. it can. This optical pressure-sensitive adhesive sheet with a release film can be produced, for example, as follows.
First, on the release layer of the release film, a coating liquid containing the above-mentioned pressure-sensitive adhesive forming material is used, for example, using a bar coating method, knife coating method, roll coating method, blade coating method, die coating method, gravure coating method, etc. It is coated and dried to form an adhesive forming material layer. Next, on this pressure-sensitive adhesive forming material layer, another release film having a different peel strength from that of the release film is attached so that the release layer is in contact with it, and then irradiated with active energy rays. A pressure-sensitive adhesive sheet is prepared. Alternatively, an adhesive-forming material layer is provided on the release layer of one release film, and after drying, the active energy ray is irradiated, and then the other release film is stuck on this so that the release layer surface comes into contact with the release layer. An optical pressure-sensitive adhesive sheet with a film is prepared.
The thickness of the optical pressure-sensitive adhesive sheet (excluding the release film) is usually about 5 to 100 μm, preferably 10 to 50 μm.

  Examples of the release film include a polyester film such as polyethylene terephthalate, polybutylene terephthalate, and polyethylene naphthalate, a plastic film such as a polyolefin film such as polypropylene and polyethylene, and a release layer such as a silicone resin applied to the release film. Is mentioned. Although there is no restriction | limiting in particular about the thickness of this peeling film, Usually, it is about 19-150 micrometers.

[Optical member with adhesive layer]
Furthermore, this invention also provides the optical member with an adhesive layer which has a layer which consists of an optical adhesive of this invention mentioned above on an optical member.
Examples of the optical member include a polarizing plate, a retardation plate, an optical compensation film, a reflection sheet, and a brightness enhancement film. Among these, a polarizing plate and a retardation plate are preferably used. Moreover, the thickness of the adhesive layer which consists of an optical adhesive of this invention is about 5-100 micrometers normally, Preferably it is 10-50 micrometers, More preferably, it is 10-30 micrometers.
This optical member with an adhesive layer can be produced, for example, as follows.
On the release layer of the release film, a pressure-sensitive adhesive forming material layer is provided according to the method described above, and after the optical member is bonded thereon, the release film is removed and the pressure-sensitive adhesive formation material layer is exposed from the exposed surface side. Alternatively, the optical member with the pressure-sensitive adhesive layer can be produced by irradiating active energy rays from the side of the release film without removing the release film.

For example, when the optical member is a polarizing plate, the optical member with the pressure-sensitive adhesive layer of the present invention becomes a polarizing plate with a pressure-sensitive adhesive layer. This polarizing plate with an adhesive layer can be used, for example, to adhere to a liquid crystal glass cell. As the polarizing plate, a polarizing plate alone can be preferably used, but a polarizing plate formed by integrating a polarizing film and a viewing angle widening film can be particularly preferably used.
As the polarizing plate in which the polarizing film and the viewing angle widening film are integrated, for example, on one side of a polarizing film obtained by bonding a triacetyl cellulose (TAC) film to each side of a polyvinyl alcohol polarizer, for example, disco Examples thereof include those provided by applying a viewing angle widening functional layer made of a tick liquid crystal, and those obtained by bonding a viewing angle widening film with an adhesive. In this case, the optical pressure-sensitive adhesive of the present invention is preferably provided on the viewing angle widening functional layer or viewing angle widening film side.
The liquid crystal display device prepared by adhering the polarizing plate with the pressure-sensitive adhesive layer to the liquid crystal glass cell is less susceptible to light leakage even in a high temperature and high humidity environment, and has excellent adhesion durability between the polarizing plate and the liquid crystal glass cell. Yes.

  In addition, the polarizing plate with the pressure-sensitive adhesive layer can be suitably used even when it is disposed on the liquid crystal cell via a retardation plate in order to improve the viewing angle characteristics of the liquid crystal display device. That is, the optical pressure-sensitive adhesive of the present invention is applied to a polarizing plate composed of a polarizing film alone to obtain a polarizing plate with a pressure-sensitive adhesive layer, which is bonded to a retardation plate to produce a new optical member. As another method, the optical pressure-sensitive adhesive of the present invention can be applied to a phase difference plate to obtain a phase difference plate with a pressure-sensitive adhesive layer, which can be bonded to a polarizing plate. What is necessary is just to bond the newly obtained optical member with a liquid crystal glass cell and an adhesive so that the phase difference plate side may contact | connect. Here, the pressure-sensitive adhesive for bonding the retardation plate and the liquid crystal glass cell is not particularly limited, and a pressure-sensitive adhesive usually used for bonding the polarizing plate and the liquid crystal glass cell can be used. In addition, it is also preferable to apply the optical adhesive of this invention also to this new optical member, obtain a new optical member with an adhesive layer, and bond this with a liquid crystal glass cell.

(Properties of pressure-sensitive adhesive layer of optical member with pressure-sensitive adhesive layer)
The adhesive strength, reworkability, heavy release, light leakage resistance, antistatic performance and anti-deposition property of the antistatic agent of the optical member with the adhesive layer of the present invention thus obtained are evaluated by the following methods. be able to.
<Reworkability>
Reworkability means that an optical member is bonded to a liquid crystal cell via an adhesive layer, and even after a predetermined period of time, the adhesive does not adhere to the surface of the liquid crystal cell, and the optical layer with an adhesive layer can be easily This means that the member can be peeled off.
In the present invention, the pressure-sensitive adhesive layer of the polarizing plate with the pressure-sensitive adhesive layer is bonded to the glass surface, and the reworkability is judged by whether or not the adhesive force after 21 days is within a predetermined value. That is, if the adhesive strength after 21 days has passed is 30 N / 25 mm or less, it can be determined that there is usually reworkability. Furthermore, if it is 20 N / 25mm or less, it is excellent in rework property, and if it is 15 N / 25mm or less, it can be said that it is especially preferable.
The optical pressure-sensitive adhesive of the present invention can have an adhesive strength of 20 N / 25 mm or less, depending on conditions, after 21 days of sticking of the polarizing plate with the pressure-sensitive adhesive layer formed thereby.
The test method will be described in detail later.

<Light leakage resistance>
The polarizing plate with the pressure-sensitive adhesive layer of the present invention can have a ΔL ^* value of less than 1.0 or 1.0 to 2.0 in the light leakage resistance measurement described in detail later. Excellent in properties.

<Heavy release>
In the present invention, heavy release refers to a phenomenon in which the release force of the release film increases with time when the release film is released after leaving the optical member with the adhesive layer provided with the release film on the adhesive layer for a predetermined period. Say. In the present invention, for the polarizing plate with the pressure-sensitive adhesive layer after the passage of seasoning, the difference between the peeling force of the release film on the pressure-sensitive adhesive layer immediately after the progress and the peel strength after standing for 21 days at 70 ° C. is predetermined. It means to become more than the value. Specifically, from the viewpoint of resistance to heavy peeling, the peel force difference is preferably 30 mN / 25 mm or less, more preferably 20 mN / 25 mm or less, and particularly preferably 10 mN / 25 mm or less.
The polarizing plate with the pressure-sensitive adhesive layer is stored in a state where the pressure-sensitive adhesive layer is protected with a release film until it is attached to the liquid crystal cell. When a storage period becomes long, the peeling force which peels off this peeling film will rise, and when the peeling film is peeled off, the adhesive layer surface will be damaged. Therefore, it is required not to make heavy peeling.
≪Measurement method≫
A polarizing plate with an adhesive layer provided with a release film (thickness 38 μm) is cut into a size of 25 mm width × 100 mm length. The cut polarizing plate with the pressure-sensitive adhesive layer is allowed to stand for 7 days at 23 ° C. and a relative humidity of 50% RH (seasoning treatment). Next, a pressure-sensitive adhesive layer is laminated on the polarizing plate surface of the polarizing plate with the pressure-sensitive adhesive layer after completion of the seasoning treatment and fixed to the glass substrate, and then the peeling force is measured under the following conditions (peeling force α ).
Peeling speed: 300 mm / min Peeling angle: 180 °
On the other hand, the polarizing plate with the pressure-sensitive adhesive layer after the seasoning treatment was left at 70 ° C. for 21 days. Thereafter, the polarizing plate with the pressure-sensitive adhesive layer is similarly fixed to the glass substrate, and the peeling force is measured (peeling force β).
The degree of heavy peeling is evaluated by calculating “peeling force β−peeling force α”.
The optical pressure-sensitive adhesive of the present invention can suppress the value of “peeling force β-peeling force α” to about 5 mN / 25 mm depending on conditions, and can suppress heavy peeling.

<Antistatic performance>
A pressure-sensitive adhesive layer-attached polarizing plate in which a release film is laminated on the pressure-sensitive adhesive layer surface is cut into 50 mm length and width to obtain a measurement sample. The measurement sample was conditioned under conditions of 23 ° C. and 50% RH for 24 hours, and then the release film was peeled off. The surface of the pressure-sensitive adhesive layer exposed according to JIS K 6911 was used as a surface resistivity measuring device. The antistatic property is evaluated by measuring at an applied voltage of 100V. The surface resistivity of the pressure-sensitive adhesive layer of the polarizing plate with the pressure-sensitive adhesive layer of the present invention is less than 5 × 10 ¹⁰ Ω / □, and has good antistatic performance.

<Non-precipitation of antistatic agent>
The peeling film on the pressure-sensitive adhesive layer of the polarizing plate with the pressure-sensitive adhesive layer is peeled off, and the exposed pressure-sensitive adhesive layer side is attached to a glass plate to obtain a measurement sample.
The measurement sample is allowed to stand for 24 hours under a wet heat condition of 60 ° C. and a relative humidity of 90% RH, then cooled to a wet heat condition of 23 ° C. and a relative humidity of 50% RH, and visually observed through a glass to be charged. The non-precipitating property of the inhibitor is evaluated. The optical pressure-sensitive adhesive of the present invention is colorless and transparent even after the above-described conditions, and the non-precipitating property of the antistatic agent is good.

EXAMPLES Next, although an Example demonstrates this invention further in detail, this invention is not limited at all by these examples.
In addition, the performance of the optical adhesive obtained in each example and the performance of the polarizing plate with an adhesive layer were calculated | required in the way shown below.
<Performance of polarizing plate with adhesive layer>
(1) Adhesive strength (adhesive strength to non-alkali glass)
The polarizing plate with the pressure-sensitive adhesive layer is allowed to stand for 7 days under conditions of 23 ° C. and a relative humidity of 50% RH. Thereafter, the obtained polarizing plate with an adhesive layer was cut into a size of 25 mm wide × 100 mm long using a cutting device [“Super Cutter” manufactured by Hadano Seisakusho Co., Ltd.] to obtain a measurement sample.
Next, the release film was peeled from the obtained measurement sample, and then bonded to an alkali-free glass [Corning Co., Ltd., “Eagle XG”].
Next, the alkali-free glass on which the measurement sample was bonded was put into an autoclave [manufactured by Kurihara Seisakusho Co., Ltd.] and pressurized under conditions of 0.5 MPa, 50 ° C., 20 minutes, then 23 ° C., relative humidity 50 Left for 1 and 21 days under the condition of% RH.
Next, the adhesive strength of the measurement sample was measured under the following conditions using a tensile tester [Orientec Co., Ltd., “Tensilon”].
Peeling speed: 300 mm / min Peeling angle: 180 °
If the adhesive strength after 21 days of sticking is 30 N / 25 mm or less, it can be judged that there exists normal rework property. Furthermore, if it is 20 N / 25 mm or less, it is excellent in rework property, and if it is 15 N / 25 mm or less, it can be said that it is especially preferable.

(2) Surface resistivity The polarizing plate with an adhesive layer was cut into 50 mm length and width, and it was set as the measurement sample. The measurement sample was conditioned under conditions of 23 ° C. and relative humidity 50% RH for 24 hours, and then the release film was peeled off. The surface of the pressure-sensitive adhesive layer exposed according to JIS K 6911 was [Mitsubishi Chemical Co., Ltd. With “HIRESTA UP MCP-HT450”, measurement was performed at an applied voltage of 100 V, and the surface resistivity was determined.
If the surface resistivity is 5 × 10 ¹⁰ Ω / □ or less, the antistatic performance is good.

(3) Non-precipitating property of antistatic agent A measurement sample was obtained by peeling off the release film on the pressure-sensitive adhesive layer of the polarizing plate with the pressure-sensitive adhesive layer and sticking the exposed pressure-sensitive adhesive layer side to a glass plate.
The measurement sample is allowed to stand for 24 hours under a wet heat condition of 60 ° C. and RH 90%, and then cooled to a wet heat condition of 23 ° C. and a relative humidity of 50% RH. It was.
○: Colorless and transparent △: Slightly cloudy ×: Aggregate is observed on the entire surface

(4) Peeling force The polarizing plate with an adhesive layer provided with a peeling film [manufactured by Lintec Corporation, “SP-PET3811”, thickness 38 μm] was cut into a size of 25 mm width × 100 mm length. The cut polarizing plate with the pressure-sensitive adhesive layer was left for 7 days under conditions of 23 ° C. and a relative humidity of 50% RH (seasoning treatment). Next, a pressure-sensitive adhesive layer was laminated on the polarizing plate surface of the polarizing plate with the pressure-sensitive adhesive layer after completion of the seasoning treatment, and fixed to a glass substrate, and then the peeling force was measured under the following conditions (peeling force α ).
Peeling speed: 300 mm / min Peeling angle: 180 °
On the other hand, the polarizing plate with the pressure-sensitive adhesive layer after the seasoning treatment was left at 70 ° C. for 21 days. Then, the polarizing plate with an adhesive layer was similarly fixed to the glass substrate, and peeling force was measured (peeling force (beta)).
The degree of heavy peeling was evaluated by calculating “peeling force β−peeling force α”.
From the viewpoint of preventing heavy peeling, the value of “peeling force β-peeling force α” is preferably 30 mN / 25 mm or less, more preferably 20 mN / 25 mm or less, and particularly preferably 10 mN / 25 mm or less. preferable.

(5) Light Leakage Resistance A polarizing plate with an adhesive layer (with a discotic liquid crystal layer) is adjusted to a size of 233 mm × 309 mm with a cutting device [Super cutter “PN1-600” manufactured by Sugano Seiki Seisakusho], and then alkali-free. After pasting on glass [Corning Corp., “1737”], it was pressurized with an autoclave manufactured by Kurihara Seisakusho at 0.5 MPa, 50 ° C. for 20 minutes. In addition, the said bonding was performed so that a polarizing axis might be in a crossed Nicol state on the front and back of an alkali free glass with the polarizing plate with an adhesive layer. In this state, it was left at 80 ° C. for 200 hours. Thereafter, the sample was left for 2 hours in an environment of 23 ° C. and a relative humidity of 50% RH, and the light leakage prevention property was evaluated by the following method under the same environment.
Using [MCPD-2000, manufactured by Otsuka Electronics Co., Ltd.], the brightness of each region shown in FIG. 2 is measured, and the brightness difference ΔL ^* is expressed by the formula ΔL ^* = [(b + c + d + e) / 4] −a
(Where a, b, c, d, and e are the lightness values at predetermined measurement points (one central portion of each region) in the A region, B region, C region, D region, and E region, respectively. The light leakage resistance was evaluated according to the following criteria.
A: ΔL ^* <1.0
○: 1.0 ≦ ΔL ^* ≦ 2.0
×: ΔL ^* > 2.0

(6) Durability of polarizing plate with adhesive layer (15 inch size)
A polarizing plate with an adhesive layer is adjusted to a size of 233 mm × 309 mm using a cutting device [Super Cutter “PN1-600” manufactured by Sugano Seiki Seisakusho Co., Ltd.] and then pasted on an alkali-free glass [Corning Co., “1737”]. Then, the pressure was increased under the conditions of 0.5 MPa, 50 ° C., and 20 minutes in an autoclave manufactured by Kurihara Seisakusho. Then, it put into the environment of each following durability conditions, and after 200 hours observed using a 10 magnification loupe, and evaluated durability with the following criteria.
○: There is no defect (floating, peeling, foaming, etc.) at a position of 0.3 mm or more from the end.
(Triangle | delta): There exists a fault in the position of 0.3-0.7 mm from an edge part. There is no defect at a position exceeding 0.7 mm from the end.
X: There is a defect at a position of 0.7 mm or more from the end.
<Durability conditions>
60 ° C, relative humidity 90% RH environment, 80 ° C dry environment 30 minutes heat shock test at -35 ° C to 70 ° C, 200 cycles

Examples 1-9 and Comparative Examples 1-6
A pressure-sensitive adhesive-forming material having the composition shown in Table 1 (in terms of solid content) was prepared, and a coating liquid in which toluene was added as a solvent to adjust the solid content to 20% by mass was obtained. Using the coating solution, on a release layer of a release film made of polyethylene terephthalate having a thickness of 38 μm as a release film [manufactured by Lintec Corporation, “SP-PET3811”], the thickness after drying is 20 μm. After applying with a knife type coating machine, it was dried at 90 ° C. for 1 minute to form an adhesive forming material layer.
Subsequently, the polarizing plate which consists of a polarizing film with a discotic liquid crystal layer (viewing angle expansion functional layer) was bonded so that an adhesive forming material layer and a discotic liquid crystal layer might contact. 30 minutes after pasting, ultraviolet rays (UV) were irradiated from the release film side under the following conditions to produce a polarizing plate with an adhesive layer. The thickness of the pressure-sensitive adhesive layer was 25 μm.
<UV irradiation conditions>
Fusion Co. electrodeless lamp H bulb used, illuminance 600 mW / cm ^2, light quantity 150 mJ / cm ²
As the UV illuminance / light meter, “UVPF-36” manufactured by Eye Graphics Co., Ltd. was used.
Table 2 shows the evaluation results of the performance of the pressure-sensitive adhesive, the performance of the polarizing plate with the pressure-sensitive adhesive layer, and the non-precipitation property of the antistatic agent.
Moreover, instead of bonding the pressure-sensitive adhesive forming material layer of Example 1 with the polarizing plate, another polyethylene terephthalate release film [Lintec Co., Ltd., “SP-PET3801”] was bonded.
Then, the optical adhesive sheet of the structure of peeling film / adhesive layer / peeling film was obtained by irradiating an ultraviolet-ray on the conditions similar to the case where it bonded on a polarizing plate.
Next, the release film [manufactured by LINTEC, "SP-PET3801"] is peeled off, and the exposed adhesive layer surface and the adhesive layer of the polarizing plate are subjected to corona treatment and then bonded together. Thereby, the polarizing plate with an adhesive layer was obtained.
The obtained polarizing plate with the pressure-sensitive adhesive layer had the same performance as the polarizing plate with the pressure-sensitive adhesive layer of Example 1.

[note]
1) MEA: 2- (methoxy) ethyl acrylate 2) ECA: ethyl carbitol acrylate 3) HEA: 2-hydroxyethyl acrylate 4) BA: butyl acrylate 5) AA: acrylic acid 6) M-315: Tris ( Acryloxyethyl) isocyanurate [product name]
In addition, the numerical value of (a-1), (a-2), (a-3) and other columns is the content (% by mass) of each component (structural unit) in the (A) acrylate copolymer. The numerical values in the columns (b-1) and (b-2) indicate the content (% by mass) of each component (constituent unit) in the (B) acrylic acid ester copolymer.
Moreover, as for the weight average molecular weight (Mw) of acrylic acid ester copolymer (A) and (B), the thing of 1.4 million was used for all. The measurement conditions are as follows.
<GPC measurement conditions>
GPC measuring device: “HLC-8020” manufactured by Tosoh Corporation
GPC column (passed in the following order): TSK guard column “HXL-H” manufactured by Tosoh Corporation
TSK gel “GMHXL” (× 2)
TSK gel "G2000HXL"
Measurement solvent: Tetrahydrofuran calibration curve: Polystyrene measurement temperature: 40 ° C

[note]
7) Photopolymerization initiator: Mixture of benzophenone and 1-hydroxycyclohexyl phenyl ketone in a mass ratio of 1: 1 [Cirba Specialty Chemicals, "Irgacure 500"]
8) Adduct of TDI: tolylene diisocyanate: trimethylolpropane = 3: 1 (molar ratio) 9) KBM-403: 3-glycidoxypropyltrimethoxysilane [trade name, manufactured by Shin-Etsu Chemical Co., Ltd.]
10) PyPF ₆ : 1-octyl-4-methylpyridinium hexafluorophosphate 11) KFSI: potassium bis (difluorosulfonyl) imide 12) LiTFSI: lithium bis (trifluoromethanesulfonyl) imide 13) tetraglyme: tetraethylene glycol dimethyl ether

[note]
14) WV: Polarizing plate with discotic liquid crystal layer

  The optical pressure-sensitive adhesive of the present invention has an antistatic property used when laminating an optical member such as a polarizing plate on an adherend, and has good adhesive force, removability (reworkability) and durability. And anti-bleeding agent anti-bleeding properties, and is suitable for attaching optical members such as polarizing plates.

1 Polyvinyl alcohol polarizer 2 TAC film I
2 'TAC film II
3 Adhesive Layer 4 Release Sheet 5 Surface Protection Film 10 Polarizing Plate

Claims (10)

(A) (a-1) Oxyalkylene group-containing (meth) acrylic monomer 5 to 90 mass% and (a-2) Reactive group-containing (meth) acrylic monomer 0.1 mass% or more and less than 10 mass% And (a-3) (meth) acrylic acid ester copolymer having (meth) acrylic acid alkyl ester as a structural unit, (B) (b-1) reactive group-containing (meth) acrylic monomer 5- (Meth) acrylic acid ester copolymer having 20% by mass and (b-2) (meth) acrylic acid alkyl ester 80 to 95% by mass having no reactive group as structural units, (C) molecular weight less than 1000 The polyfunctional (meth) acrylate monomer and (D) antistatic agent are contained, and the content ratio of the component (A) and the component (B) is 100: 1 to 100: 50 by mass ratio. Crosslinking adhesive forming material Optical adhesive characterized by comprising by. (C) The content of the polyfunctional (meth) acrylate monomer having a molecular weight of less than 1000 is 1 to 50 parts by mass with respect to 100 parts by mass of the total amount of the component (A) and the component (B). An optical pressure-sensitive adhesive as described in 1.   (A-1) The oxyalkylene group-containing (meth) acrylic monomer, wherein the oxyalkylene group has 2 to 4 carbon atoms and the oxyalkylene group has 1 to 10 carbon atoms. Optical adhesive.   (A-2) Reactive group containing (meth) acrylic-type monomer is a hydroxyl-containing (meth) acrylic-type monomer, The optical adhesive in any one of Claims 1-3. (B-1) The reactive group-containing (meth) acrylic monomer is a carboxyl group-containing (meth) acrylic monomer, The optical pressure-sensitive adhesive according to any one of claims 1 to 4.   (D) Content of antistatic agent is 0.1-10 mass parts with respect to 100 mass parts of total amounts of (A) component, (B) component, and (C) component, Claims 1-5 The optical pressure-sensitive adhesive according to any one of the above.   The optical pressure-sensitive adhesive according to any one of claims 1 to 6, wherein the pressure-sensitive adhesive-forming material further contains (E) a crosslinking agent.   The optical adhesive sheet with a peeling film formed using the optical adhesive in any one of Claims 1-7.   The optical member with an adhesive layer which has a layer which consists of an optical adhesive in any one of Claims 1-7 on an optical member.   The optical member with an adhesive layer according to claim 9, wherein the optical member is a polarizing plate.

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