KR102281768B1 - adhesion composition, an adhesive and adhesion sheet - Google Patents

Abstract

Provided are a pressure-sensitive adhesive composition, a pressure-sensitive adhesive, and a pressure-sensitive adhesive sheet that do not adversely affect an adherend such as a transparent conductive film and have excellent durability.
A (meth)acrylic acid ester polymer (A) having a weight average molecular weight of 1 million to 2.5 million and comprising a monomer having a hydroxyl group, a monomer having an aromatic ring, and a monomer having a carboxyl group as a monomer unit constituting the polymer, and an isocyanate type It contains a crosslinking agent (B), a silane coupling agent (C) having a mercapto group, and an active energy ray-curable component (D), wherein the (meth)acrylic acid ester polymer (A) is a monomer unit constituting the polymer, The adhesive composition which contains 1-5 mass % of monomers which have a hydroxyl group, 5-30 mass % of monomers which have an aromatic ring, and contains 0.1-0.8 mass % of monomers which have a carboxyl group.

Description

Adhesive composition, adhesive and adhesive sheet {adhesion composition, an adhesive and adhesion sheet}

The present invention relates to a pressure-sensitive adhesive composition, a pressure-sensitive adhesive (a material obtained by curing the pressure-sensitive adhesive composition) and a pressure-sensitive adhesive sheet, and more particularly, to a pressure-sensitive adhesive composition suitable for an optical member such as a polarizing plate, an pressure-sensitive adhesive, and a pressure-sensitive adhesive sheet.

In recent years, in various electronic devices, a touch panel that serves both as a display device and an input means has been widely used. Types of the touch panel mainly include resistive film type, capacitive type, optical type and ultrasonic type, resistive film type includes analog resistive film type and matrix resistive type type, and capacitive type includes surface type and projection type.

In touch panels in mobile electronic devices, such as smartphones and tablet terminals, which are attracting attention in recent years, many projection-type capacitive types are used. As a projected capacitive touch panel in such a mobile electronic device, for example, sequentially from the bottom up, a liquid crystal display (LCD), an adhesive layer, a transparent conductive film (tin-doped indium oxide: ITO), a glass substrate, transparency It has been proposed that a protective layer such as an electric film (ITO) and tempered glass is laminated.

As an optical component constituting the liquid crystal display device, a liquid crystal cell is generally used. The liquid crystal cell generally has the alignment layer of the two transparent electrode substrates on which the alignment layer is formed, arranged so as to be spaced at a predetermined distance by a spacer, and the periphery is sealed, and liquid crystal is placed between the two transparent electrode substrates. material is inserted. In general, a polarizing plate is adhered to the outside of the two transparent electrode substrates in the liquid crystal cell through an adhesive.

Here, in the structure which bonds the polarizing plate of a liquid crystal display device to transparent conductive film (ITO) through an adhesive layer as mentioned above, an adhesive comes into direct contact with ITO. Therefore, in the adhesive containing many carboxyl groups which are an acid component, the problem of corroding ITO or changing the resistance value of ITO arises.

As an adhesive for optics, what appears in patent document 1 is known, for example. This pressure-sensitive adhesive contains 50 to 90 mass% of (meth)acrylic acid alkylester monomer having 4 to 12 carbon atoms, 3 to 10 mass% of (meth)acrylic acid alicyclic alkylester monomer, and 0.1 to (meth)acrylic acid hydroxyl alkylester monomer. 1.0 mass%, and a copolymer (a hydroxyl group in the copolymer, but not a carboxyl group) consisting of 3 to 10 mass% (100 mass% in total) of an alkylester monomer having 1 to 3 carbon atoms of (meth)acrylic acid, It consists of a weight average molecular weight of 700,000-1.2 million), a crosslinking agent (0.02-1 mass part with respect to 100 mass parts of copolymers), and a crosslinking adjuvant (0.5-5.0 mass parts with respect to 100 mass parts of copolymers). Since this adhesive does not contain the carboxyl group which is an acid component, the above-mentioned problem does not arise easily.

Patent Document 1: Japanese Patent Application Laid-Open No. 2012-001647

On the other hand, with the thinning of mobile electronic devices in recent years, thinning of the polarizing plate which is a structural member is also progressing. Specifically, a polarizing plate with a thin film thickness of a protective film that holds polyvinyl alcohol, which is a polarizer, from both sides is used. In such a polarizing plate, since the ability to prevent thermal contraction of the polarizer by the protective film is inferior, thermal contraction tends to be larger than that of the prior art. In addition, as a material of the protective film, an optical functional film that easily generates outgas, such as cycloolefin polymer (COP), is being applied instead of triacetyl cellulose. Therefore, the reliability (durability) higher than now is calculated|required of the adhesive used for them.

However, when the adhesive of patent document 1 is used for the above polarizing plates, durability is not enough and floatation and peeling will generate|occur|produce on high temperature conditions or on wet heat conditions.

The present invention has been made in view of the actual situation, and an object of the present invention is to provide a pressure-sensitive adhesive composition, pressure-sensitive adhesive, and pressure-sensitive adhesive sheet having excellent durability without adversely affecting an adherend such as a transparent conductive film.

In order to achieve the above object, the first present invention has a weight average molecular weight of 1 million to 2.5 million, and as a monomer unit constituting the polymer, a monomer having a hydroxyl group, a monomer having an aromatic ring, and a monomer having a carboxyl group. A (meth)acrylic acid ester polymer (A), an isocyanate-based crosslinking agent (B), a silane coupling agent having a mercapto group (C), and an active energy ray-curable component (D) are contained, the (meth)acrylic acid ester The polymer (A) contains 1 to 5 mass% of the monomer having a hydroxyl group as a monomer unit constituting the polymer, 5 to 30 mass% of the monomer having an aromatic ring, and a monomer having a carboxyl group A pressure-sensitive adhesive composition containing 0.1 to 0.8% by mass is provided (Invention 1).

The pressure-sensitive adhesive obtained by crosslinking the pressure-sensitive adhesive composition according to the invention (invention 1) is a (meth)acrylic acid ester polymer (A), as a monomer unit constituting the polymer, a monomer having a hydroxyl group, a monomer having an aromatic ring, and a carboxyl group Each containing a predetermined amount of the monomers having a mercapto group, the silane coupling agent (C) having an excellent coupling effect, and the active energy ray-curable component (D) curing (meth) acrylic acid ester polymer (A) ), by being entangled with the crosslinked product, etc., it becomes excellent in durability. Moreover, since the quantity of the carboxyl group contained in the (meth)acrylic acid ester polymer (A) is suppressed low, inconvenience of to-be-adhered objects, such as a transparent conductive film, by an acid can be suppressed.

In the invention (invention 1), the isocyanate-based crosslinking agent (B) is preferably trimethylolpropane-modified tolylene diisocyanate (invention 2).

In the said invention (invention 1, 2), it is preferable that content of the said isocyanate type crosslinking agent (B) in the said adhesive composition is 0.01-1 mass part with respect to 100 mass parts of the said (meth)acrylic acid ester polymer (A). (Invention 3).

In the said invention (inventions 1-3), it is preferable that content of the said silane coupling agent (C) in the said adhesive composition is 0.01-0.5 mass part with respect to 100 mass parts of said (meth)acrylic acid ester polymers (A). (Invention 4).

In the above inventions (Inventions 1-4), it is preferable that the monomer having an aromatic ring is 2-phenylethyl (meth)acrylate (Invention 5).

In the above inventions (Inventions 1 to 5), the active energy ray-curable component (D) is preferably a polyfunctional acrylate-based monomer having a molecular weight of less than 1000 (Invention 6).

In the invention (invention 6), the polyfunctional acrylate-based monomer preferably has a cyclic structure (invention 7).

In the invention (inventions 1 to 7), the content of the active energy ray-curable component (D) in the pressure-sensitive adhesive composition is 1 to 50 parts by mass with respect to 100 parts by mass of the (meth)acrylic acid ester polymer (A). preferred (invention 8).

The 2nd this invention provides the adhesive formed by hardening the said adhesive composition (Inventions 1-8) by irradiation of an active energy ray (Invention 9).

In the invention (invention 9), the gel fraction is preferably 55 to 85% (invention 10).

In the said inventions (inventions 9 and 10), it is preferable that the storage modulus at 23 degreeC is 0.15-0.3 MPa, and it is preferable that the storage modulus at 80 degreeC is 0.05-0.2 MPa (invention 11).

A third aspect of the present invention provides a pressure-sensitive adhesive sheet having a base material and a pressure-sensitive adhesive layer, wherein the pressure-sensitive adhesive layer comprises the pressure-sensitive adhesive (Inventions 9 to 11) (Invention 12).

In the invention (Invention 12), the substrate is preferably an optical member (Invention 13).

In the said invention (Invention 13), it is preferable that the said optical member is a polarizing plate (Invention 14).

A fourth aspect of the present invention is a pressure-sensitive adhesive sheet having two release sheets and a pressure-sensitive adhesive layer sandwiched between the release sheets so as to be in contact with the release surfaces of the two release sheets, wherein the pressure-sensitive adhesive layer is formed of the pressure-sensitive adhesive (Inventions 9 to 11). It provides an adhesive sheet, characterized in that made (Invention 15).

In the above inventions (Inventions 12 to 15), when a wet heat promotion test in which the laminate of the pressure-sensitive adhesive layer and the transparent conductive film is exposed to an atmosphere of 65° C. and 95% RH for 500 hours is performed, the following formula of the transparent conductive film It is preferable that the rate of increase of the resistance value calculated by ? is 15% or less (Invention 16).

Resistance increase rate (%)={(RR ₀ )/R ₀ }×100

(Wherein, R ₀ is the initial resistance value before the moist heat acceleration test, and R is the resistance value after the moist heat acceleration test.)

According to the pressure-sensitive adhesive composition, pressure-sensitive adhesive, and pressure-sensitive adhesive sheet according to the present invention, it does not adversely affect an adherend such as a transparent conductive film, and is excellent in durability.

1 is a cross-sectional view of an adhesive sheet according to a first embodiment of the present invention.
2 is a cross-sectional view of an adhesive sheet according to a second embodiment of the present invention.
3 is a cross-sectional view of a resistance value measurement sample prepared in Test Example 3. FIG.
4 is a perspective view illustrating a test method in Test Example 3. FIG.

EMBODIMENT OF THE INVENTION Hereinafter, embodiment of this invention is described.

[Adhesive composition]

The pressure-sensitive adhesive composition according to the present embodiment (hereinafter referred to as "adhesive composition P") has a weight average molecular weight of 1 million to 2.5 million, and as a monomer unit constituting the polymer, a monomer having a hydroxyl group (a hydroxyl group-containing monomer) and an aromatic ring A (meth)acrylic acid ester polymer (A) containing a monomer having (aromatic ring-containing monomer) and a monomer having a carboxyl group (a carboxyl group-containing monomer), an isocyanate-based crosslinking agent (B), and a silane coupling agent having a mercapto group (C) ) and an active energy ray-curable component (D), Preferably, a photoinitiator (E) is further contained. Moreover, the (meth)acrylic acid ester polymer (A) contains 1-5 mass % of a hydroxyl-containing monomer as a monomer unit constituting the polymer, and contains 5-30 mass % of an aromatic ring-containing monomer, A carboxyl group-containing monomer 0.1-0.8 mass % contains. In addition, in this specification, (meth)acrylic acid ester means both an acrylic acid ester and a methacrylic acid ester. The same is true for other similar terms. In addition, the concept of a "copolymer" shall also be included in "polymer".

In the adhesive composition P, the (meth)acrylic acid ester polymer (A) contains, as monomer units constituting the polymer, a hydroxyl group-containing monomer, an aromatic ring-containing monomer, and a carboxyl group-containing monomer in predetermined amounts, respectively, to obtain the adhesive composition P The adhesive obtained by hardening has both cohesive force and stress relaxation property, and becomes excellent in durability.

In addition, when the adhesive composition P is cured, the mercapto group of the silane coupling agent (C) easily forms a thiourethane bond with the isocyanate group of the isocyanate-based crosslinking agent (B), and the other isocyanate group of the isocyanate-based crosslinking agent (B) is ( The (meth)acrylic acid ester polymer (A) is crosslinked by reacting with the hydroxyl group of the meth)acrylic acid ester polymer (A) to form a first three-dimensional network structure. And the alkoxysilyl group of the silane coupling agent (C) has an appropriate distance from the (meth)acrylic acid ester polymer (A), and it is estimated that it will become a form suspended by the (meth)acrylic acid ester polymer (A). Thereby, the outstanding coupling effect is exhibited. On the other hand, the plurality of active energy ray-curable components (D) combine with each other to form a second three-dimensional network structure. It is assumed that the first three-dimensional network structure and the second three-dimensional network structure are entangled with each other to form an integral three-dimensional network structure (this structure is hereinafter referred to as "structure X"). By this structure X and said coupling effect, the adhesive obtained becomes excellent in adhesive durability also under high temperature conditions and moist heat conditions.

Moreover, in the said adhesive composition P, since content of the carboxyl group-containing monomer which (meth)acrylic acid ester polymer (A) contains as a monomer unit is suppressed low, the sticking object of the adhesive obtained is inconvenience caused by acid, for example Even in the case of a transparent conductive film, a metal film, etc., they can suppress the inconvenience caused by an acid. In particular, when the affixing object is a transparent conductive film, corrosion of the transparent conductive film or changing the resistance value of the transparent conductive film can be suppressed.

(1) (meth)acrylic acid ester polymer (A)

The (meth)acrylic acid ester polymer (A) is a monomer unit constituting the polymer, and in addition to the hydroxyl group-containing monomer, the aromatic ring-containing monomer and the carboxyl group-containing monomer, (meth)acrylic acid alkylester having 1 to 20 carbon atoms in the alkyl group It is preferable to contain, and it is especially preferable to contain it as a main component. Moreover, you may contain another monomer as needed.

A (meth)acrylic acid ester polymer (A) can express preferable adhesiveness by containing the C1-C20 (meth)acrylic acid alkylester of an alkyl group as a monomer unit which comprises the polymer. Examples of the (meth)acrylic acid alkyl ester having 1 to 20 carbon atoms in the alkyl group include methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, (meth)acrylate n-butyl, (meth) Acrylic acid n-pentyl, (meth)acrylic acid n-hexyl, (meth)acrylic acid 2-ethylhexyl, (meth)acrylic acid isooctyl, (meth)acrylic acid n-decyl, (meth)acrylic acid n-dodecyl, (meth)acrylic acid Myristyl, (meth)acrylic acid palmityl, (meth)acrylic acid stearyl, etc. are mentioned. Among them, from the viewpoint of further improving the adhesiveness, (meth)acrylic acid ester having 1 to 8 carbon atoms in the alkyl group is preferable, and methyl (meth)acrylate and n-butyl (meth)acrylate are particularly preferable. Moreover, these may be used independently and may be used in combination of 2 or more type.

It is preferable that the (meth)acrylic acid ester polymer (A) contains 50-93.9 mass % of (meth)acrylic acid alkylester of C1-C20 alkyl group as a monomer unit which comprises the polymer, especially 64.2-93 mass It is preferable to contain %, and it is more preferable to contain 80-90 mass %. Moreover, when the (meth)acrylic acid alkylester is contained 50 mass % or more, suitable adhesiveness can be provided to the (meth)acrylic acid ester polymer (A). Moreover, when (meth)acrylic-acid alkylester shall be 93.9 mass % or less, another monomer component can be introduce|transduced in a suitable quantity in (meth)acrylic-acid ester polymer (A).

The (meth)acrylic acid ester polymer (A) contains a hydroxyl group-containing monomer as a monomer unit constituting the polymer. The hydroxyl group is highly reactive with the isocyanate group of the isocyanate-based crosslinking agent (B), and by their reaction, the (meth)acrylic acid ester polymer (A) is crosslinked with the isocyanate-based crosslinking agent (B). By this crosslinked structure, the adhesive obtained becomes excellent in durability.

As a hydroxyl-containing monomer, For example, (meth)acrylic acid 2-hydroxyethyl, (meth)acrylic acid 2-hydroxypropyl, (meth)acrylic acid 3-hydroxypropyl, (meth)acrylic acid 2-hydroxybutyl, and (meth)acrylic acid hydroxyalkyl esters such as (meth)acrylic acid 3-hydroxybutyl and (meth)acrylic acid 4-hydroxybutyl, among them, from the viewpoint of reactivity with the isocyanate-based crosslinking agent (B), 2-hydroxyethyl (meth)acrylate or 4-hydroxybutyl (meth)acrylate is preferred. These may be used independently and may be used in combination of 2 or more type.

A (meth)acrylic acid ester polymer (A) contains 1-5 mass % of a hydroxyl-containing monomer as a monomer unit which comprises the polymer, Preferably it contains 2-4 mass %. When content of a hydroxyl-containing monomer exists in said range, the crosslinked structure formed becomes favorable, and the adhesive obtained has the outstanding durability. If content of a hydroxyl-containing monomer is less than 1 mass %, there are too few crosslinking points, cohesive force falls, and the adhesive obtained does not exhibit the outstanding durability. On the other hand, when the content of the hydroxyl group-containing monomer exceeds 5% by mass, there are too many crosslinking points, and the resulting pressure-sensitive adhesive becomes inflexible, and the stress relaxation property decreases, thereby making it impossible to cope with the shrinkage of the substrate, resulting in poor durability.

The (meth)acrylic acid ester polymer (A) contains an aromatic ring-containing monomer as a monomer unit constituting the polymer. Thereby, the (meth)acrylic acid ester polymer (A) will have moderate hardness, coexistence of cohesive force and stress relaxation property is easy for the adhesive obtained, and it becomes excellent in durability.

Examples of the aromatic ring-containing monomer include phenyl (meth)acrylate, 2-phenylethyl (meth)acrylate, benzyl (meth)acrylate, naphthyl (meth)acrylate, phenoxyethyl (meth)acrylate, (meth) Phenoxybutyl acrylate, ethoxylated o-phenylphenol acrylate, phenoxydiethylene glycol (meth)acrylate, ethylene oxide modified cresol (meth)acrylate, ethylene oxide (EO) modified nonylphenol (meth)acrylate, etc. Among them, 2-phenylethyl (meth)acrylate is preferable from the viewpoint of improving cohesive force. These may be used independently and may be used in combination of 2 or more type.

(meth)acrylic acid ester polymer (A) contains 5-30 mass % of an aromatic ring containing monomer as a monomer unit which comprises the polymer, Preferably it contains 7-25 mass %, Especially preferably, it contains 10-20 mass %. % by mass. When content of an aromatic ring containing monomer exists in said range, the stress relaxation property excellent in the adhesive obtained and the outstanding durability are acquired. When content of an aromatic ring containing monomer is less than 5 mass %, durability of the adhesive obtained worsens. Moreover, even if content of an aromatic ring containing monomer exceeds 30 mass %, the compounding quantity of another component reduces and durability of the adhesive obtained worsens.

The (meth)acrylic acid ester polymer (A) contains a carboxyl group-containing monomer as a monomer unit constituting the polymer. The carboxyl group promotes a crosslinking reaction between the hydroxyl group in the (meth)acrylic acid ester polymer (A) and the isocyanate-based crosslinking agent (B), and the carboxyl group itself also performs a crosslinking reaction with the isocyanate-based crosslinking agent (B). Thereby, the grade of crosslinking becomes a thing suitable for the adhesive obtained, and when the degree of crosslinking between (meth)acrylic acid ester polymers (A) becomes equal, it becomes excellent in durability.

The (meth)acrylic acid ester polymer (A) contains 0.1 to 0.8 mass% of a carboxyl group-containing monomer as a monomer unit constituting the polymer, preferably 0.1 to 0.5 mass%, particularly preferably 0.1 to 0.3 mass% % contains When a carboxyl group containing monomer exists in said range, the adhesive obtained has the outstanding durability. When content of a carboxyl group containing monomer is less than 0.1 mass %, durability of the adhesive obtained worsens. On the other hand, when the content of the carboxyl group-containing monomer exceeds 0.8% by mass, the transparent conductive film or the like is corroded or the resistance value of the transparent conductive film is greatly changed when the object to be pasted of the obtained pressure-sensitive adhesive is a transparent conductive film.

The other monomer is a monomer that does not contain a functional group reactive with the isocyanate-based crosslinking agent (B) even in order not to interfere with the reaction between the hydroxyl group of the hydroxyl group-containing monomer and the carboxyl group of the carboxyl group-containing monomer with the isocyanate-based crosslinking agent (B). is preferable Examples of such other monomers include (meth)acrylic acid alkoxyalkyl esters such as methoxyethyl (meth)acrylate and ethoxyethyl (meth)acrylate, non-crosslinkable acrylamide such as acrylamide and methacrylamide, ( (meth)acrylic acid ester, vinyl acetate, etc. which have non-crosslinkable tertiary amino groups, such as meth)acrylic-acid N,N- dimethylamino ethyl, (meth)acrylic-acid N,N- dimethylaminopropyl, etc. are mentioned. These may be used independently and may be used in combination of 2 or more type.

A random copolymer may be sufficient as the polymerization form of a (meth)acrylic acid ester polymer (A), and a block copolymer may be sufficient as it.

The weight average molecular weights of (meth)acrylic acid ester polymer (A) are 1 million - 2.5 million, Preferably it is 1.4 million - 2.2 million, Especially preferably, it is 1.8 million - 2 million. In addition, the weight average molecular weight in this specification is the value of polystyrene conversion measured by the gel permeation chromatography (GPC) method.

When the weight average molecular weight of the (meth)acrylic acid ester polymer (A) is less than 1 million, the obtained pressure-sensitive adhesive is inferior in durability. When the weight average molecular weight of the (meth)acrylic acid ester polymer (A) exceeds 2.5 million, the adhesive obtained will be inferior to workability.

Moreover, in the adhesive composition P, the (meth)acrylic acid ester polymer (A) may be used individually by 1 type, and may be used in combination of 2 or more type. Moreover, the adhesive composition P may further contain the (meth)acrylic acid ester polymer which does not contain a hydroxyl-containing monomer, an aromatic ring-containing monomer, or a carboxyl group-containing monomer as a structural monomer unit.

(2) isocyanate-based crosslinking agent (B)

The isocyanate-based crosslinking agent (B) has the advantage of being excellent in the reactivity with the hydroxyl group of the (meth)acrylic acid ester polymer (A) and the reactivity with the mercapto group of the silane coupling agent (C).

The isocyanate-based crosslinking agent (B) contains at least a polyisocyanate compound. As a polyisocyanate compound, For example, aromatic polyisocyanate, such as tolylene diisocyanate, diphenylmethane diisocyanate, xylylene diisocyanate, aliphatic polyisocyanate, such as hexamethylene diisocyanate, isophorone diisocyanate, hydrogenated diisocyanate Alicyclic polyisocyanates such as phenylmethane diisocyanate, and their biuret forms, isocyanurates, and low molecular weight active hydrogen-containing compounds such as ethylene glycol, propylene glycol, neopentyl glycol, trimethylolpropane, and castor oil and adducts as reactants. Among them, trimethylolpropane-modified aromatic polyisocyanate, particularly trimethylolpropane-modified tolylene diisocyanate, is preferable from the viewpoint of durability and workability when used in a polarizing plate. . The said isocyanate type crosslinking agent (B) can be used individually by 1 type or in combination of 2 or more type.

The content of the isocyanate-based crosslinking agent (B) in the pressure-sensitive adhesive composition P is preferably 0.01 to 1 parts by mass, particularly preferably 0.05 to 0.5 parts by mass, with respect to 100 parts by mass of the (meth)acrylic acid ester polymer (A), and It is more preferable that it is 0.1-0.3 mass part. When content of an isocyanate type crosslinking agent (B) exists in the said range, in the adhesive obtained, the crosslinked structure excellent in stress relaxation property and durability can be formed.

(3) Silane coupling agent (C)

The silane coupling agent (C) in this embodiment has a mercapto group. This mercapto group readily reacts with the isocyanate group of the isocyanate-based crosslinking agent (B). As described above, in the pressure-sensitive adhesive obtained by curing the pressure-sensitive adhesive composition P, the alkoxysilyl group of the silane coupling agent (C) is at an appropriate distance from the (meth)acrylic acid ester polymer (A), that is, a plurality of isocyanate groups in the isocyanate-based crosslinking agent (B). It is assumed to be in a form suspended from the (meth)acrylic acid ester polymer (A) with a distance between them. In this way, when the alkoxysilyl group exists at an appropriate distance from the (crosslinked) (meth)acrylic acid ester polymer (A), an excellent coupling effect is exhibited, and the pressure-sensitive adhesive obtained thereby has excellent adhesion and under high temperature conditions. The adhesion durability is excellent even under moist heat conditions. This effect is particularly remarkably exhibited when the target of the adhesive is an inorganic material such as glass or metal.

The silane coupling agent (C) is an organosilicon compound having at least one mercapto group and at least one alkoxysilyl group in the molecule, has good compatibility with the pressure-sensitive adhesive component, and has light transmittance, for example, substantially Transparent is suitable.

Specific examples of the silane coupling agent (C) include a mercapto group-containing low molecular weight silane couple such as 3-mercaptopropyl trimethoxysilane, 3-mercaptopropyl triethoxysilane, and 3-mercaptopropyl dimethoxymethylsilane. ringer; A silane compound containing a mercapto group, such as 3-mercaptopropyl trimethoxysilane, 3-mercaptopropyl triethoxysilane, and 3-mercaptopropyl dimethoxymethylsilane, and methyltriethoxysilane, ethyltriethoxysilane, methyl and mercapto group-containing oligomeric silane coupling agents such as cocondensates with alkyl group-containing silane compounds such as trimethoxysilane and ethyltrimethoxysilane. Among them, from the viewpoint of improving durability, a mercapto group-containing oligomeric silane coupling agent is preferable, and a cocondensate of a mercapto group-containing silane compound and an alkyl group-containing silane compound is particularly preferable, and 3-mercaptopropyl trimethoxy More preferred are cocondensates of silane and methyltriethoxysilane. These may be used individually by 1 type, and may be used in combination of 2 or more type.

It is preferable that content of the silane coupling agent (C) in adhesive composition P is 0.01-0.5 mass part with respect to 100 mass parts of (meth)acrylic acid ester polymers (A), It is especially preferable that it is 0.1-0.4 mass part. When content of a silane coupling agent (C) is less than 0.01 mass part, the effect by the silane coupling agent (C) may be hard to be acquired. On the other hand, when content of a silane coupling agent (C) exceeds 0.5 mass part, reaction of an isocyanate type crosslinking agent (B) and a (meth)acrylic acid ester polymer (A) may be inhibited.

(4) active energy ray-curable component (D)

The active energy ray-curable component (D) does not interfere with the effects of the present invention and is not particularly limited as long as it is a component that is cured by irradiation with active energy ray, and may be any of a monomer, an oligomer, or a polymer, or a mixture thereof. Among them, polyfunctional acrylate-based monomers having a molecular weight of less than 1000 excellent in compatibility with the (meth)acrylic acid ester polymer (A) and the like are preferably mentioned.

Examples of the polyfunctional acrylate-based monomer having a molecular weight of less than 1000 include 1,4-butanediol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, and neopentylglycol di(meth)acryl. rate, polyethylene glycol di(meth)acrylate, neopentyl glycol adipate di(meth)acrylate, hydroxypivalic acid neopentylglycol di(meth)acrylate, dicyclofentyl di(meth)acrylate, capro Bifunctional types such as lactone-modified dicyclopentenyl di(meth)acrylate, ethylene oxide-modified phosphoric acid di(meth)acrylate, di(acryloxyethyl)isocyanurate, and arylated cyclohexyl di(meth)acrylate ; Trimethylolpropane tri(meth)acrylate, dipentaerythritol tri(meth)acrylate, propionic acid modified dipentaerythritol tri(meth)acrylate, pentaerythritol tri(meth)acrylate, propylene oxide modified trime trifunctional types such as tyrolpropane tri(meth)acrylate and tris(acryloxyethyl)isocyanurate; tetrafunctional types such as diglycerol tetra(meth)acrylate and pentaerythritol tetra(meth)acrylate; 5 functional types, such as propionic acid modified dipentaerythritol penta (meth)acrylate; 6 functional types, such as dipentaerythritol hexa(meth)acrylate and caprolactone modified dipentaerythritol hexa(meth)acrylate, etc. are mentioned. These may be used individually by 1 type, and may be used in combination of 2 or more type.

Among the polyfunctional acrylate-based monomers, those having a cyclic structure in the skeleton are preferable because of excellent durability. The cyclic structure may be a carbocyclic structure or a heterocyclic structure, and may be a monocyclic structure or a polycyclic structure. Examples of the polyfunctional acrylate-based monomer include those having an isocyanurate structure such as di(acryloxyethyl) isocyanurate and tris(acryloxyethyl) isocyanurate, and dimethyloldicyclo Pentane diacrylate, ethylene oxide modified hexahydrophthalic acid diacrylate, tricyclodecane dimethanol acrylate, adamantane diacrylate, etc. are mentioned.

As the active energy ray-curable component (D), an active energy ray-curable acrylate-based oligomer can also be used. The acrylate-based oligomer preferably has a weight average molecular weight of 50,000 or less. Examples of such an acrylate oligomer include polyester acrylate, epoxy acrylate, urethane acrylate, polyether acrylate, polybutadiene acrylate, and silicone acrylate.

Here, the polyester acrylate-based oligomer is, for example, by esterifying the hydroxyl groups of a polyester oligomer having hydroxyl groups at both terminals obtained by condensation of a polyhydric carboxylic acid and a polyhydric alcohol with (meth)acrylic acid, or It can obtain by esterifying the hydroxyl group of the terminal of the oligomer obtained by adding alkylene oxide to main acid with (meth)acrylic acid. The epoxy acrylate oligomer can be obtained by, for example, reacting (meth)acrylic acid with an oxirane ring of a relatively low molecular weight bisphenol-type epoxy resin or novolak-type epoxy resin to esterify it. Moreover, the epoxy acrylate oligomer of the carboxyl modification type which modified|denatured this epoxy acrylate type oligomer partly with dibasic carboxylic acid anhydride can also be used. The urethane acrylate oligomer can be obtained by, for example, esterifying a polyurethane oligomer obtained by reaction of polyether polyol or polyester polyol with polyisocyanate with (meth)acrylic acid. The polyol acrylate oligomer can be obtained by esterifying a hydroxyl group of a polyether polyol with (meth)acrylic acid.

The weight average molecular weight of the acrylate-based oligomer is preferably 50,000 or less, particularly preferably 500 to 50,000, and more preferably 3,000 to 40,000. These acrylate-type oligomers may be used individually by 1 type, and may be used in combination of 2 or more type.

Moreover, as an active energy ray-curable component (D), the adduct acrylate type polymer in which the group which has a (meth)acryloyl group was introduce|transduced into the side chain can also be used. Such an adduct acrylate-based polymer uses a copolymer of (meth)acrylic acid ester and a monomer having a crosslinkable functional group in the molecule, and a (meth)acryloyl group and crosslinking in a part of the crosslinkable functional group of the copolymer. It can be obtained by reacting a compound having a group that reacts with a sexual functional group.

The (meth)acrylic acid ester preferably contains (meth)acrylic acid alkylester having 1 to 20 carbon atoms in the alkyl group, for example, methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylic acid , (meth) butyl acrylate, (meth) acrylate pentyl, (meth) acrylic acid hexyl, (meth) acrylic acid cyclohexyl, (meth) acrylic acid 2-ethylhexyl, (meth) acrylate isooctyl, (meth) acrylic acid decyl, (meth) acrylate ) Acrylic acid dodecyl, (meth)acrylic acid myristyl, (meth)acrylic acid palmityl, (meth)acrylic acid stearyl, etc. are mentioned. These may be used independently and may be used in combination of 2 or more type.

It is preferable that the monomer which has a crosslinkable functional group in the said molecule|numerator contains at least 1 sort(s) selected from a hydroxyl group, a carboxyl group, an amino group, and an amide group as a functional group. As such a monomer, for example, (meth)acrylic acid 2-hydroxyethyl, (meth)acrylic acid 2-hydroxypropyl, (meth)acrylic acid 3-hydroxypropyl, (meth)acrylic acid 2-hydroxybutyl, ( (meth)acrylic acid hydroxyalkyl esters such as 3-hydroxybutyl acrylate and 4-hydroxybutyl (meth)acrylic acid; acrylamides such as acrylamide, methacrylamide, N-methyl acrylamide, N-methyl methacrylamide, N-methylol acrylamide, and N-methylol methacrylamide; (meth)acrylic acid monoalkylaminoalkyl, such as (meth)acrylic acid monomethylaminoethyl, (meth)acrylic acid monoethylaminoethyl, (meth)acrylic acid monomethylaminopropyl, and (meth)acrylic acid monoethylaminopropyl; and ethylenically unsaturated carboxylic acids such as acrylic acid, methacrylic acid, crotonic acid, maleic acid, itaconic acid, and citraconic acid. These monomers may be used independently and may be used in combination of 2 or more type.

Examples of the compound having a (meth)acryloyl group and a group reactive with a crosslinkable functional group include 2-methacryloyloxyethyl isocyanate, methacrylic acid 2-(0-[1'-methylpropylideneamino] Carboxyamino)ethyl, 2-[(3,5-dimethylpyrazolyl)carbonylamino]ethyl methacrylate, 1,1-(bisacryloyloxymethyl)ethyl isocyanate, 2-acryloyloxyethyl isocyanate, 2-acryloyloxyethyl succinate, 2-acryloyloxyethyl hexahydrophthalimide, ω-carboxy-polycaprolactone monoacrylate, phthalic acid monohydroxyethyl acrylate, 2-hydroxy-3- Phenoxypropyl acrylate etc. are mentioned preferably. These compounds may be used independently and may be used in combination of 2 or more type.

It is preferable that the weight average molecular weight of the said adduct acrylate-type polymer is about 300,000-2 million, and it is especially preferable that it is 500,000-850,000.

The active energy ray-curable component (D) may be used by selecting one type from among the aforementioned polyfunctional acrylate-based monomers, acrylate-based oligomers and adduct acrylate-based polymers, or may be used in combination of two or more types. , can also be used in combination with other active energy ray-curable components.

The content of the active energy ray-curable component (D) in the adhesive composition P is preferably 1 to 50 parts by mass, particularly preferably 2 to 20 parts by mass, with respect to 100 parts by mass of the (meth)acrylic acid ester polymer (A), Moreover, it is more preferable that it is 3-10 mass parts. It is estimated that the adhesive obtained from the adhesive composition P containing an active energy ray-curable component (D) in this range forms the said structure X favorably. In particular, when the content of the active energy ray-curable component (D) is 3 to 10 parts by mass, it is estimated that the structure X can achieve both flexibility and cohesive force in a high dimension, and it becomes an adhesive having particularly excellent durability.

(5) Photoinitiator (E)

When using an ultraviolet-ray as an active energy ray irradiated with respect to the adhesive composition P, it is preferable that the adhesive composition P contains a photoinitiator (E) further. By containing the photoinitiator (E) in this way, the active energy ray-curable component (D) can be cured efficiently, and the polymerization curing time and the irradiation amount of the active energy ray can be reduced.

Examples of the photopolymerization initiator (E) include benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzoin n-butyl ether, benzoin isobutyl ether, acetophenone, dimethylaminoaceto Phenone, 2,2-dimethoxy-2-phenylacetophenone, 2,2-diethoxy-2-phenylacetophenone, 2-hydroxy-2-methyl-1-phenyl propan-1-one, 1-hydroxy Cyclohexylphenylketone, 2-methyl-1-[4-(methylthio)phenyl]-2-morpholinopropan-1-one, 4-(2-hydroxyethoxy)phenyl-2-(hydroxy- 2-propyl) ketone, benzophenone, p-phenylbenzophenone, 4,4'-diethylaminobenzophenone, dichlorobenzophenone, 2-methylanthraquinone, 2-ethylanthraquinone, 2-t-butylanthraquinone, 2-aminoanthraquinone, 2-methylthioxanthone, 2-ethylthioxanthone, 2-chlorothioxanthone, 2,4-dimethylthioxanthone, 2,4-diethylthioxanthone, benzyldimethylketal, Acetophenone dimethyl ketal, p-dimethylamino benzoate ester, oligo [2-hydroxy-2-methyl-1 [4- (1-methylvinyl) phenyl] propanone], 2,4,6-trimethylbenzoyl-diphenyl -phosphine oxide etc. are mentioned. These may be used independently and may be used in combination of 2 or more type.

It is preferable to use a photoinitiator (E) in the quantity of 2-15 mass parts, especially 5-12 mass parts with respect to 100 mass parts of active energy ray-curable components (D).

(6) Various additives

To the pressure-sensitive adhesive composition P, if desired, various additives commonly used in acrylic pressure-sensitive adhesives, such as antistatic agents, tackifiers, antioxidants, ultraviolet absorbers, light stabilizers, softeners, fillers, refractive index modifiers, etc. can be added. .

Specific examples of the antistatic agent include N-butyl-4-methylpyridium hexafluorophosphite, N-hexyl-4-methylpyridium hexafluorophosphate, N-butyl-2-hexylpyridium perchlorate, bis(fluoro Rosulfonylimide)potassium (KFSI), bis(trifluoromethanesulfonylimide)potassium (KTFSI), bis(fluorosulfonylimide)lithium (LiFSI), bis(trifluoromethanesulfonium) imide) lithium (LiTFSI), N-butyl-2-hexylpyridium bis(trifluoromethanesulfonyl)imide, and the like. These antistatic agents may be used individually by 1 type, and may be used in combination of 2 or more type.

[Method for producing adhesive composition]

The adhesive composition P is a (meth)acrylic acid ester polymer (A) obtained by preparing a (meth)acrylic acid ester polymer (A), an isocyanate-based crosslinking agent (B), a silane coupling agent (C), and an active energy ray-curable component While mixing (D), if desired, it can manufacture by adding a photoinitiator (E), an additive, etc. in arbitrary steps.

The (meth)acrylic acid ester polymer (A) can be produced by polymerizing a mixture of monomer units constituting the polymer by a conventional radical polymerization method. Polymerization of (meth)acrylic acid ester polymer (A) can be performed by the solution polymerization method etc. using a polymerization initiator as needed. Examples of the polymerization solvent include ethyl acetate, n-butyl acetate, isobutyl acetate, toluene, acetone, hexane, and methyl ethyl ketone, and two or more types may be used in combination.

As a polymerization initiator, an azo-type compound, an organic peroxide, etc. are mentioned, You may use 2 or more types together. As the azo compound, for example, 2,2'-azobisisobutyronitrile, 2,2'-azobis(2-methylbutyronitrile), 1,1'-azobis(cyclohexane 1- carbonitrile), 2,2'-azobis(2,4-dimethylvaleronitrile), 2,2'-azobis(2,4-dimethyl-4-methoxyvaleronitrile), dimethyl 2,2' -Azobis(2-methylpropionate), 4,4'-azobis(4-cyanovaleric acid), 2,2'-azobis(2-hydroxymethylpropionitrile), 2,2' -Azobis[2-(2-imidazolin-2-yl)propane] etc. are mentioned.

Examples of the organic peroxide include benzoyl peroxide, t-butylperbenzoate, cumene hydroperoxide, diisopropylperoxydicarbonate, di-n-propylperoxydicarbonate, di(2-ethoxyethyl)peroxydi carbonate, t-butyl peroxyneodecanoate, t-butyl peroxybivalate, (3,5,5-trimethylhexanoyl) peroxide, dipropionyl peroxide, diacetyl peroxide, and the like.

Further, in the polymerization step, the weight average molecular weight of the obtained polymer can be adjusted by adding a chain transfer agent such as 2-mercaptoethanol.

After the (meth)acrylic acid ester polymer (A) is obtained, in a solution of the (meth)acrylic acid ester polymer (A), an isocyanate-based crosslinking agent (B), a silane coupling agent (C), an active energy ray-curable component (D), and A photoinitiator (E), a diluting solvent, an additive, etc. are added as needed, and the adhesive composition P (coating solution) diluted with the solvent is obtained by fully mixing.

Examples of the diluting solvent for diluting the adhesive composition P to obtain a coating solution include aliphatic hydrocarbons such as hexane, heptane and cyclohexane, aromatic hydrocarbons such as toluene and xylene, halogenated hydrocarbons such as methylene chloride and ethylene chloride, and methanol , alcohols such as ethanol, propanol, butanol and 1-methoxy-2-propanol, ketones such as acetone, methyl ethyl ketone, 2-pentanone, isophorone and cyclohexanone, esters such as ethyl acetate and butyl acetate, and ethyl Cellosolve solvents, such as cellosolve, etc. are used.

The concentration and viscosity of the coating solution prepared in this way may be within a range that can be coated, and is not particularly limited, and may be appropriately selected depending on the situation. For example, it is diluted so that the density|concentration of the adhesive composition P may become 10-40 mass %. In addition, when obtaining a coating solution, addition of a diluent solvent etc. is not a necessary condition, and as long as the adhesive composition P has a coatable viscosity, etc., it is not necessary to add a diluent solvent. In this case, the adhesive composition P becomes a coating solution using the polymerization solvent of the (meth)acrylic acid ester polymer (A) as a diluent as it is.

[adhesive]

The pressure-sensitive adhesive according to the present embodiment can be preferably obtained by applying the pressure-sensitive adhesive composition P to a desired object and drying the pressure-sensitive adhesive composition P by curing the pressure-sensitive adhesive composition P by irradiation with an active energy ray. After these treatments, if necessary, a curing period of about 1 to 2 weeks may be set at normal temperature (eg, 23°C, 50%RH). When this curing period is required, an adhesive (layer) is formed after the lapse of a curing period, and after active energy ray irradiation when a curing period is unnecessary.

Although drying of the adhesive composition P may be performed by wind drying, it is normally performed by heat processing (preferably hot air drying). When heat-processing, it is preferable that it is 50-150 degreeC, and, as for a heating temperature, it is especially preferable that it is 70-120 degreeC. Further, the heating time is preferably 10 seconds to 10 minutes, and particularly preferably 50 seconds to 2 minutes.

As active energy rays, ultraviolet rays, electron beams, and the like are usually used. Although the irradiation amount of an active energy ray changes with the kind of energy ray, for example, in the case of an ultraviolet-ray, 50-1000 mJ/cm<^2> is preferable as a light quantity, and 100-500 mJ/cm<^2> is especially preferable. Moreover, in the case of an electron beam, about 10-1000 krad is preferable.

Through the above heat treatment (and curing), the (meth)acrylic acid ester polymer (A) is crosslinked with the isocyanate-based crosslinking agent (B) to form a first three-dimensional network structure. In addition, the mercapto group of the silane coupling agent (C) easily reacts with the isocyanate group of the isocyanate-based crosslinking agent (B), and the alkoxysilyl group of the silane coupling agent (C) is passed through the isocyanate-based crosslinking agent (B), (meth) It is estimated that it exists with an appropriate distance from the acrylic acid ester polymer (A), and furthermore, the said three-dimensional network structure, and exhibits the outstanding coupling effect. On the other hand, by irradiation with active energy rays, the plurality of active energy ray-curable components (D) are bonded to each other to form a second three-dimensional network structure. It is estimated that the second three-dimensional network structure and the first three-dimensional network structure are entangled with each other to form the aforementioned structure X. The pressure-sensitive adhesive having the structure X has excellent durability because it has high cohesive force while having adequate adhesion and stress relaxation properties.

Moreover, the adhesive obtained by hardening the adhesive composition P has an appropriate cohesive force by containing an aromatic ring in spite of the said 1st three-dimensional network structure being in a comparatively loose state. Thereby, stress relaxation property can be improved without reducing cohesion force, and durability of an adhesive becomes high. In addition, due to the excellent coupling effect of the silane coupling agent (C), the adhesiveness to the glass surface or the like is excellent, and excellent adhesion durability is exhibited even under high temperature conditions or moist heat conditions. The pressure-sensitive adhesive is prevented and suppressed from generating floatation, peeling, bubbles, etc. even when placed under a high temperature condition of 85°C or a moist heat condition of 60°C/90%RH for 250 hours, for example.

It is preferable that the gel fraction of the adhesive by this embodiment is 55 to 85 %, and it is especially preferable that it is 60 to 80 %. When a gel fraction is less than 55 %, the cohesive force of an adhesive may run short, and durability and rework property may fall. In particular, when using for a COP polarizing plate, sufficient adhesive durability under high temperature may not be acquired. On the other hand, when the gel fraction exceeds 85%, the stress relaxation property becomes too low and durability may decrease.

The storage modulus of elasticity (G') at 23° C. of the pressure-sensitive adhesive according to the present embodiment is preferably 0.15 to 0.3 MPa, particularly preferably 0.18 to 0.28 MPa, from the viewpoint of durability, further improving the haze value From a viewpoint, it is preferable that it is 0.20-0.26 MPa. Moreover, it is preferable that it is 0.05-0.2 MPa from a durable viewpoint, and, as for storage modulus (G') at 80 degreeC, it is especially preferable that it is 0.08-0.18 MPa, and from a viewpoint of making a haze value more excellent, 0.1-0.14 It is preferable that it is MPa. In addition, the said storage modulus (G') is a value measured by the torsional shearing method mentioned later.

[Adhesive sheet]

As shown in Fig. 1, the pressure-sensitive adhesive sheet 1A according to the first embodiment includes, sequentially from the bottom, the release sheet 12, the pressure-sensitive adhesive layer 11 laminated on the release surface of the release sheet 12, , composed of a substrate 13 laminated on the pressure-sensitive adhesive layer 11 .

Further, as shown in Fig. 2, the pressure-sensitive adhesive sheet 1B according to the second embodiment includes two release sheets 12a and 12b, and the release surfaces of the two release sheets 12a and 12b. It is composed of an adhesive layer 11 sandwiched between two release sheets 12a and 12b. In the present specification, the release surface of the release sheet refers to the surface having peelability in the release sheet, and includes both the surface subjected to the peeling treatment and the surface showing the peelability even without performing the peeling treatment.

In any of the adhesive sheets 1A and 1B, the adhesive layer 11 consists of the adhesive obtained by hardening|curing the adhesive composition P mentioned above.

The thickness of the pressure-sensitive adhesive layer 11 is appropriately determined depending on the purpose of use of the pressure-sensitive adhesive sheets 1A and 1B, but is usually in the range of 5 to 100 μm, preferably 10 to 60 μm, for example, an optical member, particularly a polarizing plate. When using as an adhesive layer for dragons, it is 10-50 micrometers, It is preferable that it is especially 15-30 micrometers.

There is no restriction|limiting in particular as the base material 13, Any thing used as a base material sheet of a normal adhesive sheet can be used. For example, in addition to a desired optical member, a woven or nonwoven fabric using fibers such as rayon, acrylic, and polyester; synthetic paper; papers such as fine paper, glazing paper, impregnated paper, and coated paper; metal foils such as aluminum and copper; Foams, such as a urethane foam and a polyethylene foam; Polyester films such as polyethylene terephthalate, polybutylene terephthalate and polyethylene naphthalate, polyurethane films, polyethylene films, polypropylene films, cellulose films such as triacetyl cellulose, polyvinyl chloride films, polyvinylidene chloride films, poly plastic films such as vinyl alcohol films, ethylene-vinyl acetate copolymer films, polystyrene films, polycarbonate films, acrylic resin films, norbornene-based resin films, and cycloolefin resin films; These two or more types of laminated bodies, etc. are mentioned. The plastic film may be uniaxially stretched or biaxially stretched.

Examples of the optical member include a polarizing plate (polarizing film), a polarizer, a retardation plate (retardation film), a viewing angle compensation film, a brightness improving film, a contrast enhancing film, a liquid crystal polymer film, a diffusing film, a transflective film, etc. can be heard Among them, the polarizing plate (polarizing film) is easily contracted and has a large dimensional change, so it is suitable as a substrate for forming the pressure-sensitive adhesive (the pressure-sensitive adhesive layer 11) of the present embodiment from the viewpoint of requiring durability. In particular, a polycycloolefin-based film or a polarizing plate (COP polarizing plate) provided with the film is easily contracted, has a large dimensional change, has a large contact angle, and has low adhesion, so from the viewpoint that adhesion and adhesion durability are required. , It is suitable as a base material which forms the adhesive (the said adhesive layer 11) of this embodiment.

Although the thickness of the base material 13 changes with the kind, for example, in the case of an optical member, it is 10-500 micrometers normally, Preferably it is 50-300 micrometers, Especially preferably, it is 80-150 micrometers.

The release sheets 12, 12a, 12b include, for example, a polyethylene film, a polypropylene film, a polybutene film, a polybutadiene film, a polymethylpentene film, a polyvinyl chloride film, a vinyl chloride copolymer film, and a polyethylene terephthalate film. , polyethylene naphthalate film, polybutylene terephthalate film, polyurethane film, ethylene vinyl acetate film, ionomer resin film, ethylene/(meth)acrylic acid copolymer film, ethylene/(meth)acrylic acid ester copolymer film, polystyrene film , a polycarbonate film, a polyimide film, a fluororesin film, etc. are used. Moreover, these crosslinked films are also used. Moreover, these laminated|multilayer films may be sufficient.

It is preferable that the peeling surface (particularly the side in contact with the pressure-sensitive adhesive layer 11) of the release sheet is subjected to a peeling treatment. Examples of the release agent used in the peeling treatment include alkyd-based, silicone-based, fluorine-based, unsaturated polyester-based, polyolefin-based, and wax-based release agents.

Although there is no restriction|limiting in particular about the thickness of the release sheets 12, 12a, 12b, Usually, it is about 20-150 micrometers.

In order to manufacture the pressure-sensitive adhesive sheet 1A, a solution (coating solution) containing the pressure-sensitive adhesive composition P is applied and dried on the release surface of the release sheet 12 to form a coating film of the pressure-sensitive adhesive composition P, and then a substrate is applied to the coating film (13) is laminated. Then, the coating film is irradiated with an active energy ray through the release sheet 12 . The coating film becomes the pressure-sensitive adhesive layer 11 as it is when the curing period is unnecessary, and becomes the pressure-sensitive adhesive layer 11 after the curing period has elapsed when the curing period is required. Drying and curing conditions are the same as described above.

In addition, in order to manufacture the pressure-sensitive adhesive sheet 1B, a coating solution containing the pressure-sensitive adhesive composition is applied and dried on the release surface of one release sheet 12a (or 12b) to form a coating film of the pressure-sensitive adhesive composition P. , The release surface of the other release sheet 12b (or 12a) is superimposed on the coating film. Then, the coating film is irradiated with an active energy ray through the release sheet 12a (or 12b). The coating film becomes the pressure-sensitive adhesive layer 11 as it is when the curing period is unnecessary, and becomes the pressure-sensitive adhesive layer 11 after the curing period has elapsed when the curing period is required.

As a method of applying the coating solution, for example, a bar coating method, a knife coating method, a roll coating method, a blade coating method, a die coating method, a gravure coating method, or the like can be used.

The pressure-sensitive adhesive layer 11 in the pressure-sensitive adhesive sheets 1A and 1B preferably has a haze value (value measured in accordance with JIS K7136:2000) of 1.0% or less, particularly preferably 0.9% or less, and 0.8% or less. more preferably. When the haze value is 1.0 % or less, transparency is very high, and it becomes suitable as an optical use.

Here, for example, in order to manufacture a liquid crystal display device composed of a liquid crystal cell and a polarizing plate, a polarizing plate is used as the base material 13 of the adhesive sheet 1A, and the release sheet 12 of the adhesive sheet 1A is peeled off. What is necessary is just to bond the exposed adhesive layer 11 and a liquid crystal cell together.

Further, for example, in order to manufacture a liquid crystal display device in which a retardation plate is disposed between a liquid crystal cell and a polarizing plate, as an example, first, one release sheet 12a (or 12b) of the adhesive sheet 1B is peeled off, and the adhesive sheet The exposed pressure-sensitive adhesive layer 11 of (1B) and the retardation plate are bonded together. Then, the release sheet 12 of the pressure-sensitive adhesive sheet 1A using a polarizing plate as the base material 13 is peeled off, and the exposed pressure-sensitive adhesive layer 11 of the pressure-sensitive adhesive sheet 1A and the retardation plate are bonded together. The other release sheet 12b (or 12a) is peeled off from the pressure sensitive adhesive layer 11 of the pressure sensitive adhesive sheet B, and the exposed pressure sensitive adhesive layer 11 of the pressure sensitive adhesive sheet B and the liquid crystal cell are further bonded together.

According to the pressure-sensitive adhesive sheets 1A and 1B described above, since the pressure-sensitive adhesive layer 11 has excellent durability, floating, peeling, foaming, etc. occur between the base material 13 and the adherend even under high temperature conditions or under moist heat conditions. is prevented and suppressed. In particular, even when the base material 13 is a COP polarizing plate, stress that may be caused by deformation of the COP polarizing plate can be absorbed and alleviated by the pressure-sensitive adhesive layer 11, whereby excellent durability is exhibited.

It is also preferable that the adhesive sheets 1A and 1B according to the present embodiment use a transparent conductive film as an adherend. The amount of the carboxyl group-containing monomer contained as a monomer unit in the (meth)acrylic acid ester polymer (A) in the adhesive composition P is small as described above, and it is to suppress the adverse effect of the acid component on the transparent conductive film. Specifically, it is possible to suppress corrosion of the transparent conductive film or change in the resistance value of the transparent conductive film.

Examples of the transparent conductive film include metals such as platinum, gold, silver and copper, oxides such as tin oxide, indium oxide, cadmium oxide, zinc oxide, and zinc dioxide, tin-doped indium oxide (ITO), and zinc oxide doped. Composite oxides such as indium oxide, fluorine-doped indium oxide, antimony-doped tin oxide, fluorine-doped tin oxide, and aluminum-doped zinc oxide, and non-oxidized compounds such as chalcogenides, lanthanum hexaboride, titanium nitride, and titanium carbide; can

If the change in the resistance value of the transparent conductive film is specifically described, the pressure-sensitive adhesive layer 11 and the transparent conductive film are bonded together using the pressure-sensitive adhesive sheet 1A or the pressure-sensitive adhesive sheet 1B according to the present embodiment. When a moist heat promotion test is performed in which the transparent conductive film is exposed to an atmosphere of 65° C. and 95% RH for 500 hours, the increase rate of the resistance value calculated by the following formula of the transparent conductive film is preferably 15% or less, and particularly preferably 10% or less.

Resistance increase rate (%)={(RR ₀ )/R ₀ }×100

(Wherein, R ₀ is the initial resistance value (Ω) before the moist heat acceleration test, and R is the resistance value (Ω) after the moist heat acceleration test.)

In addition, the detail of the measuring method of the resistance value increase rate of a transparent conductive film is mentioned later.

The adhesive sheet 1A using a polarizing plate as the base material 13 (hereinafter sometimes referred to as "polarizing plate with an adhesive layer") preferably has an adhesive force to alkali-free glass of 0.1 to 20 N/25 mm, particularly 0.5 It is preferable that it is -10 N/25 mm, and it is still more preferable that it is 1-5 N/25 mm. When adhesive force exists in said range, floating, peeling, etc. between to-be-adhered bodies, such as a glass plate, can be prevented. In addition, the adhesive force referred to here basically refers to the adhesive force measured by the 180° peeling method according to JIS Z0237:2009, but the measurement samples are 25 mm (width) and 100 mm (length), and the measurement sample is applied to the adherend. After affixing by pressurizing at 0.5 MPa and 50 degreeC for 20 minutes, let it stand under the conditions of normal pressure, 23 degreeC, and 50%RH for 24 hours, Let it measure at the peeling rate of 300 mm/min.

The embodiments described above are described in order to facilitate understanding of the present invention, and are not described in order to limit the present invention. Accordingly, each element disclosed in the above embodiments is intended to include all design changes and equivalents falling within the technical scope of the present invention.

For example, the release sheet 12 of the pressure-sensitive adhesive sheet 1A may be omitted, and either one of the release sheets 12a and 12b of the pressure-sensitive adhesive sheet 1B may be omitted.

Example

Hereinafter, the present invention will be described in more detail by way of examples and the like, but the scope of the present invention is not limited to these examples and the like.

[Example 1]

1. Preparation of (meth)acrylic acid ester polymer

76.9 parts by mass of n-butyl acrylate, 10 parts by mass of methyl acrylate, 10 parts by mass of 2-phenylethyl acrylate, 3 parts by mass of 2-hydroxyethyl acrylate, and 0.1 parts by mass of acrylic acid were copolymerized to obtain a (meth)acrylic acid ester polymer (A). Manufactured. When the molecular weight of this (meth)acrylic acid ester polymer (A) was measured by the method mentioned later, it was 1.5 million weight average molecular weights.

2. Preparation of the adhesive composition

100 parts by mass of the (meth)acrylic acid ester polymer (A) obtained in the step (1) (in terms of solid content; the same is hereinafter), and trimethylolpropane-modified tolylene diisocyanate as an isocyanate-based crosslinking agent (B) (manufactured by Nippon Polyurethane) , trade name "Colonate L") 0.1 parts by mass and a cocondensate of 3-mercaptopropyl trimethoxysilane and methyltriethoxysilane as a silane coupling agent (C) having a mercapto group (manufactured by Shin-Etsu Chemical Co., Ltd.) , trade name "X-411-1810", mercapto equivalent: 450 g/mol) 0.3 parts by mass, and tris (acryloxyethyl) isocyanurate (manufactured by Toacose Corporation, trade name " Aronix M-315", molecular weight: 423, trifunctional) 5 parts by mass and a mixture of benzophenone and 1-hydroxycyclohexylphenyl ketone as a photoinitiator (E) in a mass ratio of 1:1 (Ciba. 0.5 parts by mass of Igacure 500) manufactured by Specialty Chemicals Corporation, thoroughly stirred, and diluted with ethyl acetate to obtain a coating solution of the adhesive composition.

Here, the formulation of the adhesive composition is shown in Table 1. In addition, details, such as abbreviation of Table 1, are as follows.

[(meth)acrylic acid ester polymer]

BA: n-butyl acrylate

MA: methyl acrylate

PhEA: 2-phenylethyl acrylate

HEA: 2-hydroxyethyl acrylate

AA : acrylic acid

[Silane coupling agent]

C1: Cocondensate of 3-mercaptopropyl trimethoxysilane and methyltriethoxysilane (Shin-Etsu Chemical Co., Ltd., trade name "X-411-1810")

C2: 3-glycidoxypropyl trimethoxysilane (manufactured by Shin-Etsu Silicone, trade name "KBM-403")

3. Manufacture of a polarizing plate with an adhesive layer

The coating solution of the obtained pressure-sensitive adhesive composition was applied to the release treatment side of a release sheet (manufactured by Lintec, SP-PET3811, thickness: 38 µm) in which one side of the polyethylene terephthalate film was peeled off with a silicone release agent, and the thickness after drying was 20 µm. After coating with a knife coater as much as possible, heat treatment was performed at 90° C. for 1 minute to form a coating film of the adhesive composition.

Next, a COP polarizing plate having a thickness of 100 μm, which is formed by protecting one side of the polarizer made of a polyvinyl alcohol film with a triacetyl cellulose film and protecting the other side with a cycloolefin polymer film, is applied to the exposed side of the coating film. It was bonded together with the said coating film so that the surface of a cycloolefin polymer film might contact. Then, the polarizing plate with an adhesive layer was obtained by irradiating an ultraviolet-ray to the said coating film on the following conditions over a release sheet, and curing it at 23 degreeC and 50 %RH for 7 days.

<Ultraviolet irradiation conditions>

・Using an electrodeless lamp and H valve manufactured by Fusion Corporation

Illuminance 600 mW/cm ² , Light intensity 150 mJ/cm ²

・UV illuminance and light meter use "UVPF-36" manufactured by Eye Graphics.

[Examples 2-13, Comparative Examples 1-4]

The type and ratio of each monomer constituting the (meth)acrylic acid ester polymer (A), the weight average molecular weight of the (meth)acrylic acid ester polymer (A), the compounding amount of the isocyanate-based crosslinking agent (B), the type of the silane coupling agent (C) And the compounding quantity, the compounding quantity of an active energy ray-curable component (D), and having changed as the compounding quantity of a photoinitiator (E) was shown in Table 1, it carried out similarly to Example 1, and produced the polarizing plate with an adhesive layer. Further, in Example 7, in the production of the pressure-sensitive adhesive composition, an equimolar mixture of lithium bis(trifluoromethanesulfoniumimide) and tetraethylene glycol dimethyl ether as an antistatic agent (manufactured by Sanko Chemical, trade name “Sankonor TGR”) ') was blended in 1.8 parts by mass.

Here, the aforementioned weight average molecular weight (Mw) is a weight average molecular weight in terms of polystyrene measured using gel permeation chromatography (GPC) under the following conditions (measured by GPC).

<Measurement conditions>

・GPC measuring device: Tosoh Corporation, HLC-8020

・GPC column (pass through in the following order): Tosoh Corporation

TSK guard column HXL-H

TSK gel GMHXL (×2)

TSK gel G2000HXL

·Measurement solvent: tetrahydrofuran

·Measured temperature: 40℃

[Test Example 1] (Measurement of gel fraction)

Instead of the polarizing plate used in the manufacture of the polarizing plate with an adhesive layer in Examples or Comparative Examples, a release sheet (manufactured by Lintec, SP-PET3801, thickness: 38 μm) in which one side of the polyethylene terephthalate film was peeled off with a silicone-based release agent was used An adhesive sheet was produced. Specifically, the release sheet is laminated on the exposed coating film of the structure made of the coating film of the release sheet/adhesive composition obtained in the manufacturing process of the Example or Comparative Example so that the release surface side is in contact, 23°C, 50%RH Curing for 7 days under the conditions of Thereby, the adhesive sheet which consists of a release sheet (SP-PET3801)/adhesive agent layer (thickness: 20 micrometers)/release sheet (SP-PET3811) was produced.

The obtained pressure-sensitive adhesive sheet was sampled in a size of 80 mm x 80 mm, the pressure-sensitive adhesive layer was wrapped with a polyester mesh (mesh size 200), and the mass of the pressure-sensitive adhesive alone was measured with a precision balance. Let the mass at this time be M1.

Next, the pressure-sensitive adhesive wrapped in the polyester mesh was immersed in ethyl acetate at room temperature (23°C) for 24 hours. After that, the pressure-sensitive adhesive was taken out and air-dried for 24 hours in an environment of a temperature of 23°C and a relative humidity of 50%, and further dried in an oven at 80°C for 12 hours. The mass of only the adhesive after drying was measured with a precision balance. Let the mass at this time be M2. The gel fraction (%) is represented by (M2/M1)×100. A result is shown in Table 2.

[Test Example 2] (Measurement of haze value)

As a measurement sample, an adhesive sheet similar to the adhesive sheet used for measuring the gel fraction was prepared. About the adhesive layer (thickness: 20 micrometers) of this adhesive sheet, haze value (%) was measured based on JISK7136:2000 using the haze meter (Nippon Denshoku-Kyo company make, NDH2000). A result is shown in Table 2.

[Test Example 3] (Measurement of resistance value increase rate)

About the polarizing plate with an adhesive layer obtained by the Example or the comparative example, the electrical resistance value of the ITO film|membrane was measured with the following test method, and the resistance value increase rate was calculated.

Fig. 3 shows a cross-sectional view of a resistance value measurement sample S. A polyethylene terephthalate (PET) film 21 provided with an ITO film 22 on one surface 21a is prepared by sputtering, and a surface 21b of the PET film 21 on which the ITO film 22 is not provided. ) and the one surface 23a of the glass plate 23 were bonded together via the bonding tape 24 (the Lintech company make, brand name "tackliner TL-70").

Next, a conductive resin material (Fujikura Kasei) containing silver on the surface of the ITO film 22 opposite to the surface in contact with the PET film 21 (hereinafter referred to as "one side") 22a. The product made by the company, trade name "FA-301 CA", dotite touch panel circuit type) is applied so as to have a rectangular electrode shape of 20 mm x 5 mm, heated at a temperature of 80 ° C. for 20 minutes, dried, and the electrode used as a measurement point of the resistance value Two points of (25) were formed. At that time, their positions were adjusted so that the distance between the two electrodes 25 and 25 was slightly larger than 20 mm.

On the other hand, the polarizing plate with an adhesive layer (1A') obtained in Examples or Comparative Examples was cut to a size of 20 mm x 250 mm, and the release sheet was peeled off (At this point, the polarizing plate with an adhesive layer (1A') was a polarizing plate 13') and the pressure-sensitive adhesive layer 11). And one side 22a of the ITO film 22 so that the adhesive layer 11 of the polarizing plate 1A' with an adhesive layer may follow the electrodes 25 and 25 of 2 points|pieces (so that it may not come into close contact) The polarizing plate 1A' with an adhesive layer was affixed to the polarizing plate 1A', and the sample S for resistance value measurement shown in FIG. 3 was produced.

_{Then, as shown in Fig. 4, the initial resistance value R 0} (Ω) between the electrodes 25 and 25 was measured using a digital high tester (manufactured by Hioki Denki, trade name “3802-50”) 30 . . In addition, after leaving the sample S for resistance value measurement in an environment of 60 degreeC and 90 %RH for 500 hours, the resistance value R(ohm) was measured after moist heat promotion. Based on the obtained initial resistance value R ₀ and the resistance value R after moist heat promotion, the resistance value increase rate of the sample S for a resistance value measurement was computed according to the following formula|equation. A result is shown in Table 2.

Resistance increase rate (%)=｛(RR ₀ )/R ₀ ｝×100

[Test Example 4] (durability evaluation)

The polarizing plate with an adhesive layer obtained in the Example or the comparative example was cut out, and the sample of the size of 200 mm x 150 mm was produced. The release sheet was peeled off from this sample, and it affixed to alkali-free glass (made by Corning, Eagle XG) via the exposed adhesive layer, Then, it pressurized at 0.5 MPa and 50 degreeC for 20 minutes in the Kurihara Seisakusho autoclave.

Then, it injected|thrown-in in the environment of the following durable conditions, and the presence or absence of a float or peeling was confirmed using a 10X magnifying glass after 250 hours. The evaluation criteria are as follows. A result is shown in Table 2.

(double-circle): Floating|lifting and peeling were not recognized.

(circle): Lifting|lifting and peeling of the magnitude|size of 0.5 mm or less were confirmed.

(triangle|delta): The floating|lifting and peeling of the magnitude|size of more than 0.5 mm and 1.0 mm or less were confirmed.

x: Floating or peeling of a size exceeding 1.0 mm was confirmed.

<Durability condition>

85℃dry

·60℃, relative humidity 90%RH

[Test Example 5] (Measurement of surface resistance value of pressure-sensitive adhesive layer)

The polarizing plate with an adhesive layer obtained in Example 7 was cut|disconnected to the size of 50 mm x 50 mm, and the obtained sample was left to stand under the temperature of 23 degreeC, and the humidity of 50 %RH for 24 hours. Thereafter, the release sheet was peeled off, and the surface resistance value (Ω/sq) of the exposed pressure-sensitive adhesive layer was measured in accordance with JIS K6911 using a resistivity meter (manufactured by Mitsubishi Chemical Analytech, Hirester UP MCP-HT450). ) was measured. A result is shown in Table 2.

Further, the surface resistance value ^{is preferably 3.0×10 11} Ω/sq or less, particularly preferably 1.0×10 ¹¹ Ω/sq or less, and ^{more preferably 8.0×10 10} Ω/sq or less. When a surface resistance value is below the said value, favorable antistatic property can be exhibited.

[Test Example 6] (Measurement of storage modulus)

As a measurement sample, an adhesive sheet similar to the adhesive sheet used for measuring the gel fraction was prepared. With respect to the pressure-sensitive adhesive layer (thickness: 20 µm) of the pressure-sensitive adhesive sheet, the pressure-sensitive adhesive layer was laminated to prepare a cylindrical test piece having a diameter of 8 mm × a thickness of 3 mm, and the storage modulus (G) ') was measured. A result is shown in Table 2.

・Measuring device: Rheometric's dynamic viscoelasticity measuring device "DYNAMIC ANALYZER RDAII"

・Frequency: 1Hz

·Temperature: 23℃ and 80℃

As can be seen from Table 2, the pressure-sensitive adhesive of the pressure-sensitive adhesive layer obtained in Examples was excellent in durability and difficult to change the resistance value of the transparent conductive film as an adherend.

The adhesive and adhesive sheet of the present invention are suitable for bonding a transparent conductive film, particularly a transparent conductive film made of tin-doped indium oxide (ITO), and an optical member, particularly a polarizing plate.

1 A, 1 B... adhesive sheet
1A'… Polarizing plate with adhesive layer
11… adhesive layer
12, 12a, 12b... release sheet
13… write
13'… Polarizer
21… PET film
21a, 21b... noodle
22… ITO membrane
22a… noodle
23… glass plate
23a… noodle
24… bonding tape
25… electrode
30… digital high tester
S… Samples for measuring resistance

Claims (17)

As an adhesive sheet provided with a base material and an adhesive layer as an optical member,
The thickness of the optical member is 10 ~ 150㎛,
The adhesive layer is
A (meth)acrylic acid ester polymer (A) having a weight average molecular weight of 1 million to 2.5 million and comprising a monomer having a hydroxyl group, a monomer having an aromatic ring, and a monomer having a carboxyl group as a monomer unit constituting the polymer;
an isocyanate-based crosslinking agent (B);
A silane coupling agent having a mercapto group (C);
Contains an active energy ray-curable component (D),
The (meth)acrylic acid ester polymer (A) contains 1 to 5% by mass of the monomer having a hydroxyl group as a monomer unit constituting the polymer, and 5 to 30% by mass of the monomer having an aromatic ring, A pressure-sensitive adhesive sheet, characterized in that the pressure-sensitive adhesive composition comprising 0.1 to 0.8 mass% of the monomer having a carboxyl group is cured by irradiation with active energy rays. According to claim 1,
The isocyanate-based crosslinking agent (B) is an adhesive sheet, characterized in that trimethylolpropane-modified tolylene diisocyanate. According to claim 1,
The content of the isocyanate-based crosslinking agent (B) in the pressure-sensitive adhesive composition is 0.01 to 1 part by mass based on 100 parts by mass of the (meth)acrylic acid ester polymer (A). According to claim 1,
The content of the silane coupling agent (C) in the pressure-sensitive adhesive composition is 0.01 to 0.5 parts by mass with respect to 100 parts by mass of the (meth)acrylic acid ester polymer (A). According to claim 1,
The monomer having the aromatic ring is a pressure-sensitive adhesive sheet, characterized in that (meth) acrylic acid 2-phenylethyl. According to claim 1,
The active energy ray-curable component (D) is an adhesive sheet, characterized in that it is a polyfunctional acrylate-based monomer having a molecular weight of less than 1000. 7. The method of claim 6,
The polyfunctional acrylate-based monomer is an adhesive sheet, characterized in that it has a cyclic structure. According to claim 1,
Content of the said active energy ray-curable component (D) in the said adhesive composition is 1-50 mass parts with respect to 100 mass parts of said (meth)acrylic acid ester polymers (A) The adhesive sheet characterized by the above-mentioned. delete According to claim 1,
The adhesive sheet, characterized in that the gel fraction of the adhesive is 55 to 85%. According to claim 1,
The adhesive sheet, characterized in that the storage modulus at 23 ° C. of the pressure-sensitive adhesive is 0.15 to 0.3 MPa, and the storage modulus at 80 ° C. is 0.05 to 0.2 MPa. delete delete According to claim 1,
The optical member is an adhesive sheet, characterized in that the polarizing plate. delete According to claim 1,
When the wet heat promotion test was performed on the laminate of the optical member, the substrate, and the pressure-sensitive adhesive layer and the transparent conductive film, exposed to an atmosphere of 65° C. and 95% RH for 500 hours, the transparent conductive film was calculated by the following formula An adhesive sheet, characterized in that the increase rate of the resistance value is 15% or less.
Resistance increase rate (%)={(RR ₀ )/R ₀ }×100
(Wherein, R ₀ is the initial resistance value before the moist heat acceleration test, and R is the resistance value after the moist heat acceleration test.) delete

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