KR102314959B1 - 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 having excellent durability even when applied to an optical member such as a polarizing plate.
A (meth)acrylic acid ester polymer (A) having a weight average molecular weight of 900,000 to 3 million and containing a monomer having an alicyclic structure as a monomer unit constituting the polymer, a crosslinking agent (B), and an active energy ray-curable component ( C).

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, a pressure-sensitive adhesive, and a pressure-sensitive adhesive sheet.

In recent years, in various electronic devices, a touch panel that serves as a display device and an input means has been widely used. Types of touch panels mainly include resistive film type, capacitive type, optical type, and ultrasonic type, resistive type includes analog resistive type and matrix resistive 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 of the projection-type capacitive type are used. As a projected capacitive touch panel in such a mobile electronic device, for example, sequentially from the bottom, 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, on the outside of the two transparent electrode substrates in the liquid crystal cell, a polarizing plate is adhered through an adhesive, respectively.

As an adhesive used for a touchscreen, what appears in patent document 1 is known, for example. This pressure-sensitive adhesive is a (meth)acrylic polymer containing 0.2 to 20 parts by weight of a carboxyl group-containing monomer as a copolymerization component with respect to 100 parts by weight of an alkyl (meth)acrylate having an alkyl group having 4 to 14 carbon atoms as a monomer unit; ) With respect to 100 parts by weight of the acrylic polymer, 0.02 to 2 parts by weight of a peroxide as a crosslinking agent, and 0.005 to 5 parts by weight of an epoxy-based crosslinking agent are contained.

Patent Document 1: Japanese Patent Application Laid-Open No. 2009-242786

In such a touch panel, a polarizing plate using a polycycloolefin-based protective film is used more often in recent years, and the polarizing plate is also becoming thinner with thinning of mobile electronic devices in recent years. However, the polycycloolefin-based material lacks adhesion to the pressure-sensitive adhesive, and since a thin polarizing plate has a high shrinkage rate, the conventional pressure-sensitive adhesive such as Patent Document 1 has low durability, over time or under high-temperature conditions. There existed a problem that floatation and peeling were easy to generate|occur|produce under a moist heat condition.

The present invention has been made in view of such an 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 even when applied to an optical member such as a polarizing plate.

In order to achieve the above object, the first present invention is a (meth)acrylic acid ester polymer (A) having a weight average molecular weight of 900,000 to 3,000,000, and containing a monomer having an alicyclic structure as a monomer unit constituting the polymer; , A crosslinking agent (B), and an active energy ray-curable component (C) are provided, The adhesive composition characterized by the above-mentioned is provided (Invention 1).

When the adhesive composition according to the invention (invention 1) is cured, the (meth)acrylic acid ester polymer (A) is crosslinked by the crosslinking agent (B) to form a first three-dimensional network structure, and a plurality of active energy ray-curable components It is presumed that (C) is combined with each other to form a second three-dimensional network structure, and 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. The pressure-sensitive adhesive obtained by curing the pressure-sensitive adhesive composition, by the action of the above structure and the alicyclic structure of the (meth)acrylic acid ester polymer (A), an optical member such as a polarizing plate, particularly a polycycloolefin-based optical member, Even when a transparent conductive film is used as a to-be-adhered body, it becomes excellent in durability.

In the invention (invention 1), the (meth)acrylic acid ester polymer (A) preferably contains 0.1 to 30% by mass of a monomer having an alicyclic structure as a monomer unit constituting the polymer (invention 2) .

In the above inventions (Inventions 1 and 2), the alicyclic structure preferably includes a cyclohexyl skeleton, a dicyclopentadiene skeleton, an adamantane skeleton or an isobornyl skeleton (Invention 3).

In the above inventions (Inventions 1 to 3), it is preferable that the (meth)acrylic acid ester polymer (A) further contains 0.1 to 10% by mass of a monomer having a hydroxyl group as a monomer unit constituting the polymer (Invention 4) .

In the above inventions (inventions 1 to 4), it is preferable that the (meth)acrylic acid ester polymer (A) contains substantially no monomer having a carboxyl group as a monomer unit constituting the polymer (invention 5).

In the above inventions (Inventions 1 to 5), the crosslinking agent (B) is preferably an isocyanate-based crosslinking agent (Invention 6).

In the above inventions (Inventions 1 to 6), the active energy ray-curable component (C) is preferably a polyfunctional acrylate-based monomer having a molecular weight of less than 1000 (Invention 7).

In the invention (invention 7), the polyfunctional acrylate-based monomer preferably has a cyclic structure (invention 8).

In the invention (inventions 1 to 8), the content of the active energy ray-curable component (C) in the pressure-sensitive adhesive composition is 1 to 30 parts by mass with respect to 100 parts by mass of the (meth)acrylic acid ester polymer (A) preferred (invention 9).

In the said invention (invention 1-9), it is preferable to contain a photoinitiator (D) further (invention 10).

The second present invention provides an adhesive obtained by curing the pressure-sensitive adhesive composition (Inventions 1 to 10) by irradiation with an active energy ray (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 is made of the pressure-sensitive adhesive (Invention 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).

In the above inventions (Inventions 13 and 14), it is preferable that the optical member has a polycycloolefin-based film (Invention 15). In addition, "having a polycycloolefin-type film" shall include the concept of "it consists only of a polycycloolefin-type film".

A fourth aspect of the present invention is a pressure-sensitive adhesive sheet comprising 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 made of the pressure-sensitive adhesive (Invention 11). It provides an adhesive sheet characterized in (Invention 16).

When the adhesive composition by this invention contains the component of (A)-(C), the adhesive obtained has high durability and becomes suitable as objects for optical members, such as a polarizing plate.

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.

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 900,000 to 3 million, and a monomer (alicyclic structure-containing monomer) having an alicyclic structure as a monomer unit constituting the polymer. A (meth)acrylic acid ester polymer (A) containing contains more 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".

When the adhesive composition P is cured, the (meth)acrylic acid ester polymer (A) is crosslinked by the crosslinking agent (B) to form a first three-dimensional network structure. On the other hand, a plurality of active energy ray-curable components (C) 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").

The pressure-sensitive adhesive obtained by curing the pressure-sensitive adhesive composition P is an optical member such as a polarizing plate, in particular, a polycycloolefin-based optical member ( For example, even when an optical member which consists of a polycycloolefin type film, an optical member which has a polycycloolefin type film in part), or a transparent conductive film is used as a to-be-adhered body, it becomes excellent in durability.

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

The (meth)acrylic acid ester polymer (A) contains an alicyclic structure-containing monomer as a monomer unit constituting the polymer. Thereby, the adhesive obtained becomes excellent in durability as mentioned above. This effect is considered to be because the affinity and interaction between the alicyclic structure and the optical member or the transparent conductive film is relatively strong, and the adhesion and the like are improved.

The carbocyclic ring of an alicyclic structure may have a saturated structure, and may have an unsaturated bond. Further, the alicyclic structure may be a monocyclic alicyclic structure or a polycyclic alicyclic structure such as bicyclic or tricyclic structure. It is preferable that carbon number of an alicyclic structure is 5-20, It is especially preferable that it is 6-15, It is more preferable that it is 7-12.

Examples of the alicyclic structure include cyclohexyl skeleton, dicyclopentadiene skeleton, adamantane skeleton, isobornyl skeleton, cycloalkane skeleton (cycloheptane skeleton, cyclooctane skeleton, cyclononane skeleton, cyclodecane skeleton, cycloundecane skeleton, cyclododecane skeleton, etc.), cycloalkene skeleton (cycloheptene skeleton, cyclooctene skeleton, etc.), norbornene skeleton, norbornadiene skeleton, polycyclic skeleton (cuban skeleton, basketane skeleton, lower umbrella skeleton, etc.), spiro skeleton, etc., among them, those containing a cyclohexyl skeleton, dicyclopentadiene skeleton, adamantane skeleton or isobornyl skeleton exhibiting a more excellent durability improvement effect. desirable.

As said alicyclic structure-containing monomer, the (meth)acrylic acid ester monomer containing the said skeleton is preferable, Specifically, (meth)acrylic acid cyclohexyl, (meth)acrylic acid dicyclopentanyl, (meth)acrylic acid adamantyl. , (meth)acrylic acid isobornyl, acrylic acid dicyclopentenyl, (meth)acrylic acid dicyclopentenyloxyethyl, and the like, among them, (meth)acrylic acid cyclohexyl, which exhibits a more excellent durability improvement effect, ( Dicyclopentanyl meth)acrylic acid, adamantyl (meth)acrylate or isobornyl (meth)acrylic acid are preferred. These may be used individually by 1 type, and may be used in combination of 2 or more type.

The (meth)acrylic acid ester polymer (A) preferably contains 0.1 to 30% by mass of the alicyclic structure-containing monomer as a monomer unit constituting the polymer, particularly preferably 0.2 to 25% by mass, and 0.5 It is more preferable to contain -13 mass %. When the content of the alicyclic structure-containing monomer is less than 0.1% by mass, the above-described durability improvement effect is difficult to be obtained, and when the content of the alicyclic structure-containing monomer exceeds 30% by mass, adhesiveness suitable for optical applications may not be obtained. .

The (meth)acrylic acid ester polymer (A) preferably contains (meth)acrylic acid alkyl ester having 1 to 20 carbon atoms in the alkyl group in addition to the alicyclic structure-containing monomer as a monomer unit constituting the polymer, particularly as a main component It is preferable to contain it as

Since the (meth)acrylic acid ester polymer (A) contains the (meth)acrylic acid alkyl ester of C1-C20 of an alkyl group as a monomer unit which comprises the polymer, preferable adhesiveness can be expressed. 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.

The (meth)acrylic acid ester polymer (A) preferably contains 20 to 99.8 mass % of (meth)acrylic acid alkyl ester having 1 to 20 carbon atoms in the alkyl group as a monomer unit constituting the polymer, and particularly 50 to 99.5 mass% It is preferable to contain %, and it is more preferable to contain 60-99 mass %.

Moreover, it is preferable that the (meth)acrylic acid ester polymer (A) contains the monomer (hydroxyl group containing monomer) which has a hydroxyl group as a monomer unit which comprises the polymer. The hydroxyl group is highly reactive with the reactive functional group of the crosslinking agent (B), particularly the isocyanate group of the isocyanate-based crosslinking agent, and by their reaction, the (meth)acrylic acid ester polymer (A) is effectively crosslinked by the crosslinking agent (B) to form a good crosslinked structure do. Thereby, the adhesive obtained becomes more 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, (meth)acrylic acid hydroxyalkyl esters, such as (meth)acrylic acid 3-hydroxybutyl and (meth)acrylic acid 4-hydroxybutyl, etc. are mentioned, Among them, in the (meth)acrylic acid ester polymer (A) obtained From a viewpoint of the reactivity of a hydroxyl group with the crosslinking agent (B), and copolymerizability with another monomer, (meth)acrylic-acid 2-hydroxyethyl is preferable. These may be used independently and may be used in combination of 2 or more type.

The (meth)acrylic acid ester polymer (A), as a monomer unit constituting the polymer, preferably contains 0.1 to 10% by mass of a hydroxyl group-containing monomer, particularly preferably 0.2 to 8% by mass, and 0.3 to 5 It is more preferable to contain by mass %. When content of a hydroxyl-containing monomer exists in said range, the crosslinked structure formed becomes favorable, and the adhesive obtained has more outstanding durability. When content of a hydroxyl-containing monomer is less than 0.1 mass %, there are too few crosslinking points, and the durability improvement effect is hard to be acquired. On the other hand, when content of a hydroxyl-containing monomer exceeds 10 mass %, there are too many crosslinking points, the adhesive obtained becomes inflexible, and there exists a possibility that stress relaxation property may fall.

It is preferable that the (meth)acrylic acid ester polymer (A) does not contain substantially the monomer (carboxyl group-containing monomer) which has a carboxyl group as a monomer unit which comprises the polymer. By not substantially containing a monomer having a carboxyl group, which is an acid component, inconvenience caused by acid to the affixing target of the resulting adhesive, for example, even in the case of a transparent conductive film or a metal film, such inconvenience caused by acid can be suppressed. can 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. Moreover, when the silane coupling agent containing a mercapto group mentioned later is used as a silane coupling agent (E), it acts effectively also in such an acid-free system. In addition, by not substantially containing a monomer having a carboxyl group, it is possible to prevent the carboxyl group from interfering with the reaction between the hydroxyl group of the hydroxyl group-containing monomer and the crosslinking agent (B), particularly the isocyanate-based crosslinking agent.

The (meth)acrylic acid ester polymer (A) may contain other monomers as needed other than said monomer. The other monomer may be a monomer having a reactive functional group other than a hydroxyl group (a reactive functional group-containing monomer) or a non-reactive monomer.

As a reactive functional group containing monomer, the monomer (amino group containing monomer) etc. which have an amino group are mentioned, for example. Examples of the amino group-containing monomer include aminoethyl (meth)acrylate and n-butylaminoethyl (meth)acrylate. These may be used independently and may be used in combination of 2 or more type.

Examples of the non-reactive monomer include alkoxyalkyl groups such as methoxymethyl (meth)acrylate, methoxyethyl (meth)acrylate, ethoxymethyl (meth)acrylate, and ethoxyethyl (meth)acrylate (meth)acrylate. Non-crosslinkable acrylamide such as (meth)acrylic acid ester having an aromatic ring such as acrylic acid ester, (meth)acrylic acid phenyl, acrylamide, and methacrylamide, (meth)acrylic acid N,N-dimethylaminoethyl, (meth)acrylic acid (meth)acrylic acid ester, vinyl acetate, styrene, etc. which have non-crosslinkable tertiary amino groups, such as N,N- dimethylaminopropyl, 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 (meth)acrylic acid ester polymer (A) has a weight average molecular weight of 900,000 to 3,000,000, preferably 1,000,000 to 2.5,000,000, particularly preferably 1.1,000,000 to 2,000,000. 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 900,000, the obtained pressure-sensitive adhesive is inferior in durability. Moreover, when the weight average molecular weight of a (meth)acrylic acid ester polymer (A) exceeds 3 million, the adhesive force of the adhesive obtained will fall.

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 the said alicyclic structure containing monomer as a structural monomer unit.

(2) crosslinking agent (B)

As the crosslinking agent (B), any one having reactivity with respect to the reactive functional group (hydroxyl group, amino group, etc.) of the (meth)acrylic acid ester polymer (A) is sufficient, for example, an isocyanate type crosslinking agent, an epoxy type crosslinking agent, an amine type crosslinking agent, melamine crosslinking agents, aziridine crosslinking agents, hydrazine crosslinking agents, aldehyde crosslinking agents, oxazoline crosslinking agents, metal alkoxide crosslinking agents, metal chelate crosslinking agents, metal salt crosslinking agents, ammonium salt crosslinking agents, and the like. Among these, when the (meth)acrylic acid ester polymer (A) has a hydroxyl group, an isocyanate type crosslinking agent has the advantage that it is excellent in the reactivity with the hydroxyl group. A crosslinking agent (B) can be used individually by 1 type or in combination of 2 or more type.

An isocyanate type crosslinking agent contains a polyisocyanate compound at least. As a polyisocyanate compound, For example, aromatic polyisocyanate, such as tolylene diisocyanate, diphenylmethane diisocyanate, xylene diisocyanate, aliphatic polyisocyanate, such as hexamethylene diisocyanate, isophorone diisocyanate, hydrogenated diphenylmethane Alicyclic polyisocyanates such as diisocyanate, etc., and their biuret forms, isocyanurate forms, and reactants with low molecular weight active hydrogen-containing compounds such as ethylene glycol, propylene glycol, neopentyl glycol, trimethylolpropane, and castor oil Phosphorus adduct body etc. are mentioned, Among them, from a viewpoint of reactivity with the hydroxyl group of (meth)acrylic acid ester polymer (A), trimethylol propane modified|denatured aromatic polyisocyanate, especially trimethylol propane modified|denatured xylene diisocyanate, and Trimethylolpropane-modified tolylene diisocyanate is preferred.

It is preferable that content of the crosslinking agent (B) in the adhesive composition P is 0.05-3 mass parts with respect to 100 mass parts of (meth)acrylic acid ester polymer (A), It is especially preferable that it is 0.08-1.5 mass parts, It is 0.1-1 It is more preferable that it is a mass part. When content of a crosslinking agent (B) is 0.05 mass part or more, the durability improvement effect by the crosslinking agent (B) is acquired. When content of a crosslinking agent (B) exceeds 3 mass parts, the grade of crosslinking may become excessive and there exists a possibility that the adhesive force of the adhesive obtained may fall.

(3) active energy ray-curable component (C)

The active energy ray-curable component (C) is not particularly limited as long as it does not interfere with the effects of the present invention and is a component that is cured by irradiation with active energy rays, 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 neopentyl glycol di (meth) acrylate, dicyclopentanyl di (meth) acrylate, caprolactone bifunctional types such as 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 preferred 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 (C), 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 the polyester oligomer having hydroxyl groups at both terminals obtained by condensation of polyhydric carboxylic acid and 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 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 (C), 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. This adduct acrylate-based polymer uses a copolymer of (meth)acrylic acid ester and a monomer having a crosslinkable functional group in the molecule, and includes a (meth)acryloyl group and crosslinking in some of the crosslinkable functional groups of the copolymer. It can be obtained by reacting a compound having a group that reacts with a sexual functional group.

As said (meth)acrylic acid ester, it is preferable to contain the C1-C20 (meth)acrylic acid alkyl ester of an alkyl group, For example, (meth)acrylate, ethyl (meth)acrylate, (meth)acrylic acid Propyl, (meth)acrylate butyl, (meth)acrylic acid pentyl, (meth)acrylic acid hexyl, (meth)acrylic acid cyclohexyl, (meth)acrylic acid 2-ethylhexyl, (meth)acrylic acid isooctyl, (meth)acrylic acid decyl, ( and dodecyl (meth)acrylic acid, myristyl (meth)acrylate, palmityl (meth)acrylate, and stearyl (meth)acrylate. 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 (meth)acrylic acid and 4-hydroxybutyl (meth)acrylic acid; acrylamides such as acrylamide, methacrylamide, N-methylacrylamide, N-methylmethacrylamide, N-methylolacrylamide, and N-methylol methacrylamide; (meth)acrylic acid monoalkyl aminoalkyl, such as (meth)acrylic acid monomethylaminoethyl, (meth)acrylic acid monoethylaminoethyl, (meth)acrylic acid monomethylaminopropyl, (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-acryloyloxyethylhexahydrophthalimide, 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 (C) may be used by selecting one type from among the above-mentioned 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 (C) in the adhesive composition P is preferably 1 to 30 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), , more preferably 3 to 9 parts by mass. It is estimated that the adhesive obtained from the adhesive composition P containing an active energy ray-curable component (C) in this range forms the said structure X favorably.

(4) photoinitiator (D)

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 (D) further. Thus, by containing a photoinitiator (D), an active energy ray-curable component (C) can be hardened efficiently, and polymerization hardening time and the irradiation amount of an active energy ray can be reduced.

Examples of the photopolymerization initiator (D) 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-phenylpropan-1-one, 1-hydroxycyclo Hexylphenylketone, 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, benzyldimethyl ketal, aceto Phenonedimethylketal, p-dimethylaminobenzoic acid 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.

A photoinitiator (D) is 2-15 mass parts with respect to 100 mass parts of active energy ray-curable components (C), It is preferable to be used in the quantity of the range especially 5-12 mass parts.

(5) Silane coupling agent (E)

It is preferable that the adhesive composition P contains a silane coupling agent (E). By containing a silane coupling agent (E), durability of the adhesive obtained from the adhesive composition P can be made more excellent.

As a silane coupling agent (E), the silane coupling agent etc. which have a (meth)acryloyl group, an epoxy group, an amino group, a mercapto group etc. as a functional group which react with an organic material are mentioned preferably. Among them, the pressure-sensitive adhesive composition P particularly preferably contains a silane coupling agent having a mercapto group as a functional group that reacts with the organic material (hereinafter sometimes referred to as “mercapto group-containing silane coupling agent”).

When the adhesive composition P including the mercapto group-containing silane coupling agent is cross-linked, the mercapto group of the mercapto group-containing silane coupling agent reacts with the reactive functional group of the cross-linking agent (B). In particular, when the crosslinking agent (B) is an isocyanate crosslinking agent, the mercapto group of the silane coupling agent containing a mercapto group easily forms a thiourethane bond with the isocyanate group of the isocyanate crosslinking agent. On the other hand, the other reactive functional group of the crosslinking agent (B) (isocyanate group of the isocyanate-based crosslinking agent) reacts with the reactive functional group (hydroxyl group, amino group, etc.) of the (meth)acrylic acid ester polymer (A) to react with the (meth)acrylic acid ester polymer (A) to form a three-dimensional network structure. Then, the alkoxysilyl group of the mercapto group-containing silane coupling agent has an appropriate distance from the (crosslinked) (meth)acrylic acid ester polymer (A) and is suspended from the (meth)acrylic acid ester polymer (A). Thereby, the outstanding coupling effect is exhibited, and the adhesive obtained is excellent in adhesiveness, and even under high temperature conditions or under moist heat conditions, it becomes more excellent in durability.

When the crosslinking agent (B) is an isocyanate-based crosslinking agent, the mercapto group of the mercapto group-containing silane coupling agent easily reacts with the isocyanate group of the isocyanate-based crosslinking agent. Even if there is only a hydroxyl group which is difficult to act in a coupling agent (even if the (meth)acrylic acid ester polymer (A) does not contain a carboxyl group as a reactive functional group), the coupling effect by a mercapto group containing silane coupling agent is acquired.

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

Specific examples of such a mercapto group-containing silane coupling agent include mercapto group-containing low molecular weight silane coupling agents such as 3-mercaptopropyltrimethoxysilane, 3-mercaptopropyltriethoxysilane, and 3-mercaptopropyldimethoxymethylsilane. ringer; Mercapto group-containing silane compounds, such as 3-mercaptopropyltrimethoxysilane, 3-mercaptopropyltriethoxysilane, and 3-mercaptopropyldimethoxymethylsilane, 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-mercaptopropyltrimethoxy A cocondensate of silane and methyltriethoxysilane is more preferred. These may be used individually by 1 type, and may be used in combination of 2 or more type.

The mercapto group-containing silane coupling agent is preferably an oligomer. In such an oligomer mercapto group-containing silane coupling agent, the mercapto equivalent in the oligomer is preferably 100 to 1000 g/mol, particularly preferably 200 to 900 g/mol, and more preferably 300 to 700 g/mol. do. If the mercapto equivalent is less than 100 g/mol, there is a fear that the effect of improving the durability may decrease, and if it exceeds 1000 g/mol, there is a possibility that a decrease in adhesive strength or poor peeling may occur.

It is also preferable that the adhesive composition P contains the silane coupling agent which has an epoxy group as a functional group which reacts with an organic material. Examples of the silane coupling agent having an epoxy group include glycidyltrimethoxysilane, glycidyltriethoxysilane, glycidyltripropoxysilane, glycidyltributoxysilane, glycidyltrichloro Silane, glycidylchlorodimethoxysilane, glycidyldichloromethoxysilane, glycidylchlorodiethoxysilane, glycidyldichloroethoxysilane, glycidyltribromosilane, 3-glycidoxypropyltrimethoxysilane , 3-glycidoxypropyltriethoxysilane, 3-glycidoxypropyltripropoxysilane, 3-glycidoxypropyltributoxysilane, 3-glycidoxypropyltrichlorosilane, 3-glycidoxypropyl Chlorodimethoxysilane, 3-glycidoxypropyldichloromethoxysilane, 3-glycidoxypropylchlorodiethoxysilane, 3-glycidoxypropyldichloroethoxysilane, 3-glycidoxypropyltribromosilane, 2- (3,4-epoxycyclohexyl)ethyltrimethoxysilane, 2-(3,4-epoxycyclohexyl)ethyltriethoxysilane, 2-(3,4-epoxycyclohexyl)ethyltripropoxysilane, 2 -(3,4-epoxycyclohexyl)ethyl tributoxysilane etc. are mentioned. 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 (E) in the adhesive composition P is 0.01-5 mass parts with respect to 100 mass parts of (meth)acrylic acid ester polymer (A), It is especially preferable that it is 0.02-3 mass parts, 0.05 It is more preferably ~2 parts by mass. When content of a silane coupling agent (E) is less than 0.01 mass part, the effect by the silane coupling agent (E) is hard to be acquired. On the other hand, when content of a silane coupling agent (E) exceeds 5 mass parts, there exists a possibility that the extreme fall of adhesive force and lack of cohesion force may generate|occur|produce.

(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.

Examples of the antistatic agent include ionic liquids, ionic solids, anionic surfactants, alkali metal salts, cationic surfactants, nonionic surfactants, etc. Among them, ionic liquids, ionic It is preferable to use at least 1 sort(s) selected from a solid and an alkali metal salt.

As the ionic liquid and ionic solid, nitrogen-containing onium salts, sulfur-containing onium salts, phosphorus-containing onium salts and the like are preferable. Moreover, lithium salt, potassium salt, etc. are preferable as an alkali metal salt. These may be used independently and may be used in combination of 2 or more type.

It is preferable that content of the antistatic agent in adhesive composition P is 0.5-8 mass %, and it is especially preferable that it is 1-5 mass %. When content of an antistatic agent exists in said range, the balance of antistatic performance and durability of an adhesive becomes favorable.

[Method for producing adhesive composition]

The pressure-sensitive adhesive composition P is prepared by preparing the (meth)acrylic acid ester polymer (A), and mixing the obtained (meth)acrylic acid ester polymer (A), the crosslinking agent (B), and the active energy ray-curable component (C), if desired. Accordingly, it can be prepared by adding a photopolymerization initiator (D), a silane coupling agent (E), an additive, and the like in any step.

A (meth)acrylic acid ester polymer (A) can be manufactured by superposing|polymerizing the monomer which comprises a polymer (in the case of a copolymer, a mixture of monomers) by a normal radical polymerization method. Superposition|polymerization of the (meth)acrylic acid ester polymer (A) can be performed by the solution polymerization method etc. using a polymerization initiator as needed. As a polymerization solvent, ethyl acetate, n-butyl acetate, isobutyl acetate, toluene, acetone, hexane, methyl ethyl ketone etc. are mentioned, for example, You may use 2 or more types together.

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-butylperoxyneodecanoate, t-butylperoxybivarate, (3,5,5-trimethylhexanoyl)peroxide, dipropionylperoxide, diacetyl peroxide, and the like.

Moreover, in the said polymerization process, the weight average molecular weight of the polymer obtained can be adjusted by mix|blending a chain transfer agent, such as 2-mercaptoethanol.

When the (meth)acrylic acid ester polymer (A) is obtained, in the solution of the (meth)acrylic acid ester polymer (A), a crosslinking agent (B), an active energy ray-curable component (C), and optionally a photopolymerization initiator (D); A silane coupling agent (E), an additive, etc. are added and fully mixed, the adhesive composition P (coating solution) diluted with the solvent is obtained.

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, ethyl Cellosolve solvents, such as cellosolve, etc. are used.

As long as the concentration and viscosity of the coating solution prepared in this way can be coated, it 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 %. Moreover, when obtaining a coating solution, addition of a diluent solvent etc. is not a necessary condition, As long as the adhesive composition P is a coating-able viscosity etc., it is not necessary to add a diluent solvent. In this case, the adhesive composition P becomes a coating solution 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.

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 heating temperature, it is especially preferable that it is 70-120 degreeC. Moreover, it is preferable that they are 10 second - 10 minutes, and, as for heating time, it is especially preferable that they are 50 second - 2 minutes.

As an active energy ray, an ultraviolet-ray, an electron beam, etc. are used normally. Although the irradiation amount of an active energy ray changes with the kind of energy rays, for example, in the case of an ultraviolet-ray, 50-1000 mJ/cm<2> is preferable in 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.

By drying the adhesive composition P and irradiation with active energy rays, the (meth)acrylic acid ester polymer (A) having a crosslinkable functional group is crosslinked by the crosslinking agent (B) to form a first three-dimensional network structure, and a plurality of active energy It is presumed that the line-curable components (C) combine with each other to form a second three-dimensional network structure, and they become entangled with each other to form the above-described structure X.

The pressure-sensitive adhesive obtained by curing the pressure-sensitive adhesive composition P is an optical member such as a polarizing plate, particularly an optical member of polycycloolefin type, by the action of the alicyclic structure of the above structure X and the (meth)acrylic acid ester polymer (A); It has high durability even when a transparent conductive film is used as an adherend, and exhibits excellent durability especially under high temperature conditions or moist heat conditions. For example, even when it is left for 500 hours under a high temperature condition of 80°C or a wet heat condition of 60°C/90%RH, generation of lifting, peeling, bubbles, etc. is prevented and suppressed.

It is preferable that the gel fraction of the adhesive by this embodiment is 30 to 99 %, It is especially preferable that it is 40 to 95 %, It is more preferable that it is 76 to 90 %. When a gel fraction is less than 30 %, the cohesive force of an adhesive may run short, and durability and rework property may fall. On the other hand, when the gel fraction exceeds 99%, the adhesive force becomes too low and durability may decrease. In addition, the said gel fraction is a value after storing for 7 days in 23 degreeC, 50%RH environment from the formation of an adhesive layer (after a curing period). If it is unclear whether the curing period has elapsed, the gel fraction may fall within the above range after storage again for 7 days at 23° C. and 50% RH.

[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 is such that the two release sheets 12a and 12b and the release surfaces of the two release sheets 12a and 12b are in contact with each other. It is composed of an adhesive layer 11 sandwiched between the two release sheets 12a and 12b. In the present specification, the release surface of the release sheet refers to a surface having peelability in the release sheet, and includes both a surface subjected to a peeling treatment and a surface exhibiting peelability even without performing a peeling treatment.

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

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 When using as an adhesive layer for polarizing plates, 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 a vinyl alcohol film, an ethylene-vinyl acetate copolymer film, a polystyrene film, a polycarbonate film, an acrylic resin film, a norbornene-type resin film, and a cycloolefin resin film; 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, since a polarizing plate is easy to shrink and has a large dimensional change, it is preferable as a base material which forms the adhesive (the said adhesive layer 11) by this embodiment from a durable viewpoint. In particular, a polarizing plate in which one protective film is made of a polycycloolefin-based film (hereinafter sometimes referred to as “COP polarizing plate”) is easily contracted, undergoes large dimensional change, has a large contact angle, and has low adhesion, so it is durable. It is more preferable as a base material which forms the adhesive (the said adhesive layer 11) by this embodiment from a viewpoint.

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. Furthermore, it is preferable that the release sheets 12, 12a, 12b are transparent to active energy rays.

It is preferable that the peeling process is given to the peeling surface of the said peeling sheet (especially the surface in contact with the adhesive layer 11). As a release agent used for a peeling process, the release agent of an alkyd type, a silicone type, a fluorine type, an unsaturated polyester type, a polyolefin type, and a wax type is mentioned, for example.

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.

When manufacturing 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 layer of the pressure-sensitive adhesive composition P, and then the coating layer A substrate 13 is laminated thereon. Then, the pressure-sensitive adhesive layer 11 is formed by irradiating the coating layer with an active energy ray over the release sheet 12 . In addition, the irradiation conditions of an active energy ray are as above-mentioned.

In addition, when manufacturing the pressure-sensitive adhesive sheet 1B, a coating layer of the pressure-sensitive adhesive composition P is formed by applying and drying a coating solution containing the pressure-sensitive adhesive composition on the release surface of one release sheet 12a (or 12b). Then, the other release sheet 12b (or 12a) is laminated on the coating layer. Then, the pressure-sensitive adhesive layer 11 is formed by irradiating the coating layer with an active energy ray over the release sheet 12a (or 12b).

In addition, instead of irradiating an active energy ray over the release sheet to form the pressure-sensitive adhesive layer 11 as described above, a coating layer of the pressure-sensitive adhesive composition P is formed on the release sheet, and the coating layer is exposed to the active energy A line may be irradiated to form the pressure-sensitive adhesive layer 11 , and thereafter, a substrate or a release sheet may be laminated on the pressure-sensitive adhesive layer 11 . Moreover, you may form the coating film layer of the adhesive composition P directly on a base material, and irradiate an active energy ray to this coating film layer, and you may form the adhesive layer 11.

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.

Here, for example, when manufacturing 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 removed. What is necessary is just to bond the adhesive layer 11 and liquid crystal cell which peeled and exposed.

Further, for example, when manufacturing 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, The exposed pressure-sensitive adhesive layer 11 of the sheet 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. Further, 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 is bonded to the liquid crystal cell.

According to the above adhesive sheets 1A and 1B, since the adhesive layer 11 is excellent in durability, it floats and peels between the base material 13, such as a COP polarizing plate, and a to-be-adhered body even under high temperature conditions or under moist heat conditions. , foaming, etc. are prevented and suppressed.

Moreover, it is preferable that the haze value (value measured according to JIS K7136:2000) of the adhesive layer 11 in the adhesive sheets 1A and 1B is 2 % or less, It is especially preferable that it is 1.8 % or less, It is 1 % or less more preferably. When the haze value is 2% or less, transparency is very high, and thus it is suitable as an optical use.

On the other hand, in the pressure-sensitive adhesive sheets 1A and 1B according to the present embodiment, it is also preferable to use a transparent conductive film as an adherend. In this case, it is preferable that the (meth)acrylic acid ester polymer (A) in the adhesive composition P does not contain a carboxyl group containing monomer as a monomer unit which comprises the polymer. Thereby, it can suppress that the bad influence by an acidic component is given to a transparent conductive film. Specifically, corrosion of the transparent conductive film or changing the resistance value of the transparent conductive film can be suppressed.

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, 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, chalcogenides, lanthanum hexaboride, titanium nitride, titanium carbide, etc. can be heard

Moreover, it is preferable that the adhesive force with respect to alkali-free glass of the adhesive sheet 1A (Hereinafter, it may call "polarizing plate with an adhesive layer") using a polarizing plate as the base material 13 is 0.1-25 N/25 mm, especially It is preferable that it is 2-20 N/25mm. When adhesive force exists in said range, floating, peeling, etc. can be prevented between to-be-adhered bodies, such as a glass plate. In addition, the adhesive force here basically refers to the adhesive force measured by the 180° peeling method in accordance with JIS Z0237: 2009, but the measurement sample is 25 mm wide and 100 mm long, and the measurement sample is an adherend (alkali-free glass). It shall be measured at the peeling rate of 300 mm/min, after pressurizing and affixing at 0.5 MPa and 50 degreeC for 20 minutes with respect to 20 minutes, and leaving it to stand under the conditions of normal pressure, 23 degreeC, and 50%RH for 24 hours.

Moreover, it is preferable that the said polarizing plate with an adhesive layer sticks to the said alkali-free glass, and it is preferable that the adhesive force (adhesive force after 14 days of pasting) after leaving it to stand for 14 days is 0.5-30 N/25mm, and it is especially 1-25 N/25mm It is preferable, and it is more preferable that it is 2-20 N/25mm. Thus, since the increase in adhesive force with time is suppressed, the said polarizing plate with an adhesive layer can be evaluated as being excellent in rework property. In addition, the adhesive force referred to here also basically refers to the adhesive force measured by the 180° peeling method in accordance with JIS Z0237: 2009, but the measurement sample is 25 mm wide and 100 mm long, and the measurement sample is an adherend (alkali-free glass). After pressing and affixing at 0.5 MPa and 50°C for 20 minutes, it is allowed to stand for 14 days under the conditions of normal pressure, 23°C, and 50%RH, and then it is measured at a 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 more specifically described 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

In a reaction vessel equipped with a stirrer, a thermometer, a reflux condenser, a dropping device and a nitrogen introduction tube, 74 parts by mass of n-butyl acrylate, 5 parts by mass of methyl acrylate, 20 parts by mass of isobornyl acrylate, and 1 part by mass of 2-hydroxyethyl acrylate parts, 200 parts by mass of ethyl acetate, and 0.08 parts by mass of 2,2'-azobisisobutyronitrile were put, and the air in the reaction vessel was replaced with nitrogen gas. While stirring in this nitrogen atmosphere, the reaction solution was heated up to 60 degreeC, and after making it react for 16 hours, it cooled to room temperature. Here, the molecular weight of a part of the obtained solution was measured by the method mentioned later, and production|generation of the (meth)acrylic acid ester polymer (A) of 1.85 million weight average molecular weights (Mw) was confirmed.

2. Preparation of the adhesive composition

100 parts by mass of the (meth)acrylic acid ester polymer (A) obtained in the step (1) (solid content conversion; the same applies hereinafter), and trimethylolpropane-modified xylene diisocyanate as a crosslinking agent (B) (manufactured by Soken Chemical Co., Ltd., trade name) "TD-75") 0.4 mass parts, and tris(acryloxyethyl) isocyanurate (Toakosei company make, brand name "Aronix M-315", molecular weight: 423, 3 as an active-energy-ray-curable component (C)) 5 parts by mass of functional type, and 0.5 parts by mass of a mixture of benzophenone and 1-hydroxycyclohexylphenyl ketone as a photopolymerization initiator (D) in a mass ratio of 1:1 (Ciba Specialty Chemical Co., Ltd., Igacure 500) , a cocondensate of 3-mercaptopropyltrimethoxysilane and methyltriethoxysilane as a silane coupling agent (E) having a mercapto group as a functional group that reacts with an organic material (manufactured by Shin-Etsu Chemical, trade name “X41-1810”) ') 0.3 parts by mass was mixed, 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 description, are as follows.

[(meth)acrylic acid ester polymer (A)]

BA: n-butyl acrylate

MA: methyl acrylate

HEA: 2-hydroxyethyl acrylate

IBXA: isobornyl acrylate

ADMMA: Adamantyl methacrylate

DCPA: Dicyclofentanyl Acrylic Acid

CHA: acrylic acid cyclohexyl

PhEA: 2-phenoxyethyl acrylate

AA: acrylic acid

[Crosslinking agent (B)]

XDI: Trimethylolpropane-modified xylene diisocyanate (manufactured by Soken Chemical Co., Ltd., trade name "TD-75")

TDI: Trimethylolpropane-modified tolylene diisocyanate (manufactured by Soken Chemical, trade name "L-45")

[Silane coupling agent (E)]

E1: Cocondensate of 3-mercaptopropyltrimethoxysilane and methyltriethoxysilane (Shin-Etsu Chemical Co., Ltd., trade name "X41-1810", mercapto equivalent: 450 g/mol)

E2: 3-glycidoxypropyl trimethoxysilane (manufactured by Shin-Etsu Chemical Co., Ltd., trade name "KBM-403")

3. Manufacture of a polarizing plate with an adhesive layer

The coating solution of the obtained adhesive composition was applied with a knife coater to the release-treated surface of a release sheet (manufactured by Lintec, SP-PET3811, thickness: 38 µm) in which one surface of a polyethylene terephthalate film was peeled off with a silicone-based release agent, and then 90 A coating layer of the adhesive composition was formed by heat treatment at °C for 1 minute.

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 placed on the exposed side of the coating layer was attached to Then, the polarizing plate with an adhesive layer was obtained by irradiating an ultraviolet-ray on the following conditions over a release sheet, and making the said coating film layer into an adhesive layer. Moreover, the thickness of the adhesive layer was 20 micrometers.

<Ultraviolet irradiation conditions>

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

Illuminance 600 mW/cm2, light intensity 150 mJ/cm2

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

[Examples 2-19, 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), and a crosslinking agent (B), an active energy ray-curable component (C), a photopolymerization initiator Except having changed the kind and/or compounding quantity of (D) and a silane coupling agent (E) as Table 1 showed, it carried out similarly to Example 1, and produced the polarizing plate with an adhesive layer. Moreover, in Example 4, the adhesive composition which mix|blended further the pyridinium salt type ionic liquid (The Koei Chemical company make, brand name "IL-P18") was used as an antistatic agent.

Here, the above-mentioned 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 (GPC measurement).

<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

・Measurement 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 was laminated on the exposed pressure-sensitive adhesive layer of the structure composed of a release sheet/adhesive layer (thickness: 20 μm) obtained in the manufacturing process of Examples or Comparative Examples so that the release-treated side was in contact. Thereby, the adhesive sheet which consists of the structure of a release sheet/adhesive agent layer/release sheet was produced.

The obtained pressure-sensitive adhesive sheet was cured for 7 days at 23°C and 50%RH. Thereafter, the 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 weighed with a precision balance. Let the mass at this time be M1.

Next, the adhesive wrapped in the polyester mesh was immersed in ethyl acetate at room temperature (23 degreeC) for 24 hours. After that, the pressure-sensitive adhesive was taken out and air dried for 24 hours under 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 expressed as (M2/M1)×100. A result is shown in Table 2.

[Test Example 2] (Measurement of haze value)

As a measurement sample, an adhesive sheet (cured for 7 days) similar to the adhesive sheet used for measuring the gel fraction was prepared. About the adhesive layer (thickness: 20 micrometers) of this adhesive sheet, the haze value (%) was measured according to JISK7136:2000 using the haze meter (Nippon Denshoku-Kyo company make, NDH2000). A result is shown in Table 2.

[Test Example 3] (Measurement of adhesive force)

The polarizing plate with an adhesive layer obtained in the Example or the comparative example was cut out, and the sample of 25 mm width and 100 mm length was produced. The release sheet was peeled off from this sample, and the sample was pasted on alkali-free glass (Eagle XG, Corning) through the exposed pressure-sensitive adhesive layer. did. Then, after leaving it to stand for 24 hours (1 day) or 14 days under the conditions of 23 degreeC and 50%RH, according to JIS Z0237:2009 using the tensile tester (Orientec Corporation make, Tenshiron), peeling rate 300 mm/min. , the adhesive force (adhesive force after 1 day of sticking and 14 days after sticking; N/25mm) was measured on the conditions of 180 degrees of peeling angles. The results are shown in Table 2, respectively.

[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 233 mm x 309 mm was produced. As a sample, the thing after storing the produced polarizing plate with an adhesive layer (adhesive layer formation) in 23 degreeC and 50 %RH environment for 7 days was prepared. The release sheet was peeled off from this sample, and after affixing to alkali-free glass (made by Corning, Eagle XG) through the exposed adhesive layer, it pressurized at 0.5 MPa and 50 degreeC by the Kurihara Seisakusho autoclave for 20 minutes.

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 the 10-fold magnifying glass after 500 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 size of 0.5 mm or less were confirmed.

x: Floating|lifting and peeling of the magnitude|size of 0.6 mm or more were confirmed.

<Durability condition>

・80℃ drying

· 60℃, relative humidity 90%RH

As Table 2 showed, the adhesive of the adhesive layer obtained in the Example had high adhesive force, and was excellent also in durability.

The pressure-sensitive adhesive of the present invention is suitable for adhesion of an optical member, particularly a polarizing plate, and the pressure-sensitive adhesive sheet of the present invention is suitable as a pressure-sensitive adhesive sheet for an optical member, particularly for a polarizing plate.

1A, 1B … adhesive sheet
11 … adhesive layer
12, 12a, 12b... release sheet
13 … write

Claims (16)

A (meth)acrylic acid ester polymer (A) having a weight average molecular weight of 900,000 to 3,000,000, containing a monomer having an alicyclic structure as a monomer unit constituting the polymer, and not containing a monomer having a carboxyl group;
a crosslinking agent (B);
A pressure-sensitive adhesive composition containing an active energy ray-curable component (C),
Said (meth)acrylic acid ester polymer (A) contains 0.1-30 mass % of the monomer which has the said alicyclic structure as a monomer unit which comprises the polymer, The adhesive composition characterized by the above-mentioned. delete According to claim 1,
The alicyclic structure comprises a cyclohexyl skeleton, a dicyclopentadiene skeleton, an adamantane skeleton or an isobornyl skeleton. According to claim 1,
The (meth)acrylic acid ester polymer (A) further contains 0.1 to 10 mass % of a monomer having a hydroxyl group as a monomer unit constituting the polymer. delete According to claim 1,
The crosslinking agent (B) is a pressure-sensitive adhesive composition, characterized in that the isocyanate-based crosslinking agent. According to claim 1,
The active energy ray-curable component (C) is a pressure-sensitive adhesive composition, characterized in that the polyfunctional acrylate-based monomer having a molecular weight of less than 1000. 8. The method of claim 7,
The polyfunctional acrylate-based monomer is a pressure-sensitive adhesive composition, characterized in that it has a cyclic structure. According to claim 1,
Content of the said active energy ray-curable component (C) in the said adhesive composition is 1-30 mass parts with respect to 100 mass parts of said (meth)acrylic acid ester polymers (A) The adhesive composition characterized by the above-mentioned. According to claim 1,
A photoinitiator (D) is further contained, The adhesive composition characterized by the above-mentioned. The adhesive obtained by hardening the adhesive composition of any one of Claims 1, 3 - 4, and 6 - 10 by irradiation of an active energy ray. An adhesive sheet having a substrate and an adhesive layer, comprising:
The pressure-sensitive adhesive layer is an adhesive sheet, characterized in that made of the pressure-sensitive adhesive according to claim 11. 13. The method of claim 12,
The base material is an adhesive sheet, characterized in that the optical member. 14. The method of claim 13,
The optical member is an adhesive sheet, characterized in that the polarizing plate. 14. The method of claim 13,
The optical member is an adhesive sheet, characterized in that it has a polycycloolefin-based film. 2 release sheets,
A pressure-sensitive adhesive sheet having 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,
The pressure-sensitive adhesive layer is an adhesive sheet, characterized in that made of the pressure-sensitive adhesive according to claim 11.

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