JPWO2019021843A1 - Adhesive composition and adhesive film - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a pressure-sensitive adhesive composition capable of forming a pressure-sensitive adhesive layer having a short curing period, a low contamination property, and suppressing heavy release. The pressure-sensitive adhesive composition contains (A) a (meth)acrylic copolymer having a reactive functional group, (B) an isocyanate crosslinking agent, and (C) a metal chelate compound, The (A) (meth)acrylic copolymer is obtained by living radical polymerization, has a weight average molecular weight of 200,000 to 2,000,000, and has a molecular weight distribution (PDI) of less than 3.0. It is a feature. [Selection diagram] None

Description

The present invention relates to an adhesive composition and an adhesive film.

Image display devices such as optical films, liquid crystal displays, plasma displays, organic EL (electroluminescence) displays, and touch panels used for liquid crystal display devices have surface protection (for example, from scratches, dust, pollution, and corrosion during transportation, storage, and processing). Protection), anti-glare, anti-reflection, and scattering prevention (prevention of scattering of adherends).

This functional film has a pressure-sensitive adhesive layer for sticking to an image display device on one surface of the base film, and a pressure-sensitive adhesive film provided with a functional coating layer on the other surface as necessary. It is supposed to be in the form. The adhesive film is attached to the release film before being attached to the surface of the image display device. Further, an optical film used in a liquid crystal display device, such as a polarizing plate or a retardation plate, is attached to a liquid crystal cell using an adhesive.

Since the pressure-sensitive adhesive has excellent optical properties and is relatively easy to design, a (meth)acrylic pressure-sensitive adhesive composed of a (meth)acrylic acid ester-based copolymer and a cross-linking agent is used. Agent is used. Further, in order to obtain durability under the environment of high temperature and high humidity, an isocyanate cross-linking agent is used as the cross-linking agent.

Here, the (meth)acrylic pressure-sensitive adhesive has a problem that contaminants derived from the pressure-sensitive adhesive layer remain on the adherend when the pressure-sensitive adhesive film is peeled off from the adherend. It is considered that this is due to the low molecular weight component generated when the (meth)acrylic acid ester-based copolymer is produced. Further, such a low molecular weight component causes a problem that the adhesive strength is excessively increased when the adhesive is heated. When the adhesive is heated depending on the usage environment of the article to which the adhesive film is attached, the adhesive strength of the adhesive increases and it firmly adheres to the adherend, and peels off even after the purpose of use of the adhesive film ends. Becomes difficult. Further, even if it can be peeled off, the adhesive remains on the adherend and contaminates the adherend. Therefore, there is a demand for a (meth)acrylic acid ester-based copolymer having a small amount of low molecular weight components.

Generally, a (meth)acrylic acid ester-based copolymer is produced by a free radical polymerization method, but it is difficult to obtain a uniform copolymer composition, and as a result, a low molecular weight component (oligomer) is produced. Generate a lot. Therefore, in Patent Document 1, it is proposed to use a (meth)acrylic acid ester-based copolymer produced by a living radical polymerization method in a pressure-sensitive adhesive composition (Patent Document 1 (page 18, 5 to 10). , Lines 24-26)).

Further, when a (meth)acrylic acid ester-based copolymer obtained by a living radical polymerization method is used, it is known that delay in crosslinking and heavy exfoliation due to aging occur (Patent Document 2 (Comparative Example 1, See Comparative Example 5)). Due to the delayed crosslinking, a long curing period is required, the productivity of the pressure-sensitive adhesive film is poor, and heavy peeling causes a problem that the storage stability of the pressure-sensitive adhesive film and the work load during use increase. Therefore, in Patent Document 2, it has been proposed to use a pressure-sensitive adhesive composition composed of a (meth)acrylic acid ester-based copolymer obtained by a living radical polymerization method, an isocyanate-based cross-linking agent, and an organotin compound. (See Patent Document 2 (Claim 1)).

International Publication No. 2007/119884 JP, 2014-31442, A

However, even with the pressure-sensitive adhesive composition described in Patent Document 2, the effect of suppressing heavy release is not sufficient, and there was room for study. Further, although Patent Document 2 proposes to use an organic tin compound, there is a demand for a crosslinking accelerator which replaces the organic tin compound due to its toxicity.

The present invention has been made in view of the above circumstances, and provides a pressure-sensitive adhesive composition capable of forming a pressure-sensitive adhesive layer that has a short curing period, has a low contamination property, and has a heavy release suppressed. To aim.

The pressure-sensitive adhesive composition of the present invention which has been able to solve the above-mentioned problems is (A) a (meth)acrylic copolymer having a reactive functional group, (B) an isocyanate crosslinking agent, and (C) a metal. The (A) (meth)acrylic copolymer containing a chelate compound is obtained by living radical polymerization, has a weight average molecular weight of 200,000 to 2,000,000, and has a molecular weight distribution (PDI). It is characterized by being less than 3.0.

The pressure-sensitive adhesive composition of the present invention contains (C) a metal chelate compound, so that even when a copolymer obtained by living radical polymerization is used, it has a short curing period and low contamination, and A pressure-sensitive adhesive composition capable of forming a pressure-sensitive adhesive layer in which heavy release is suppressed is obtained.

The pressure-sensitive adhesive composition can be suitably used for optics. The present invention also includes a pressure-sensitive adhesive film having a substrate film and a pressure-sensitive adhesive layer formed from the pressure-sensitive adhesive composition. The present invention also includes an image display device including the adhesive film.

The pressure-sensitive adhesive composition of the present invention has a short curing period when forming the pressure-sensitive adhesive layer. In addition, the pressure-sensitive adhesive layer formed from the pressure-sensitive adhesive composition of the present invention has low stain resistance and suppresses heavy release from the release film.

Hereinafter, an example of a preferable mode for carrying out the present invention will be described. However, the following embodiments are merely examples. The present invention is not limited to the embodiments described below.

In the present invention, “(meth)acrylic” means “at least one of acrylic and methacrylic”. "(Meth)acrylate" means "at least one of acrylate and methacrylate". "(Meth)acryloyl" means "at least one of acryloyl and methacryloyl". “Vinyl monomer” refers to a monomer having a carbon-carbon double bond capable of radical polymerization in the molecule. The “structural unit derived from a vinyl monomer” refers to a structural unit in which a radical-polymerizable carbon-carbon double bond of a vinyl monomer is polymerized into a carbon-carbon single bond. The “structural unit derived from (meth)acrylate” refers to a structural unit in which a radical-polymerizable carbon-carbon double bond of (meth)acrylate is polymerized into a carbon-carbon single bond. The “structural unit derived from a (meth)acrylic monomer” refers to a structural unit in which a radical-polymerizable carbon-carbon double bond of a (meth)acrylic monomer is polymerized into a carbon-carbon single bond. The “structural unit derived from a vinyl monomer” refers to a structural unit in which a radical-polymerizable carbon-carbon double bond of a vinyl monomer is polymerized into a carbon-carbon single bond.

<1. Adhesive composition>
The pressure-sensitive adhesive composition of the present invention contains (A) a (meth)acrylic copolymer having a reactive functional group, (B) an isocyanate crosslinking agent, and (C) a metal chelate compound. The (A) (meth)acrylic copolymer is obtained by living radical polymerization, has a weight average molecular weight of 200,000 to 2,000,000, and has a molecular weight distribution (PDI) of less than 3.0. is there.

The pressure-sensitive adhesive composition of the present invention can shorten the curing period when forming the pressure-sensitive adhesive layer by blending (C) the metal chelate compound. In addition, the pressure-sensitive adhesive composition of the present invention contains (C) a metal chelate compound, so that even when a copolymer obtained by living radical polymerization is used, heavy release to a release film or an adherend can be achieved. Can be suppressed.

Each constituent component of the pressure-sensitive adhesive composition of the present invention will be described below.

((A) A (meth)acrylic copolymer having a reactive functional group)
The (A) reactive functional group-containing (meth)acrylic copolymer used in the present invention (hereinafter sometimes simply referred to as “(A) copolymer”) is obtained by living radical polymerization. It is a (meth)acrylic copolymer having a weight average molecular weight of 200,000 to 2,000,000, a molecular weight distribution (Mw/Mn) of less than 3.0, and having a reactive functional group.

The (meth)acrylic copolymer may be a copolymer having a structural unit derived from a (meth)acrylic monomer as a main component (50% by mass or more), and may be a vinyl monomer other than the (meth)acrylic monomer. It may contain structural units of origin. The content of the structural unit derived from the (meth)acrylic monomer in the (A) copolymer is preferably 80% by mass or more, and more preferably 90% by mass or more based on 100% by mass of the entire copolymer. The (A) copolymer may be composed only of structural units derived from a (meth)acrylic monomer.

The (A) copolymer is preferably a (meth)acrylic acid ester-based copolymer ((meth)acrylate-based copolymer). The (meth)acrylate-based copolymer may be a copolymer having a structural unit derived from (meth)acrylate as a main component (50% by mass or more), and is derived from a vinyl monomer other than (meth)acrylate. It can contain structural units. The (meth)acrylate is an ester compound formed from (meth)acrylic acid and a compound having a hydroxy group. The content of the structural unit derived from the (meth)acrylate in the (A) copolymer is preferably 80% by mass or more, and more preferably 90% by mass or more based on 100% by mass of the entire copolymer. The (A) copolymer may be composed of only structural units derived from (meth)acrylate.

The reactive functional group is a functional group capable of reacting with an isocyanate group contained in (B) an isocyanate-based crosslinking agent described later. Examples of the reactive functional group include one or more selected from the group consisting of a hydroxy group, a carboxy group, a sulfonic acid group, a phosphoric acid group, a phosphonic acid group, a phosphine group and an epoxy group. It is possible and is preferably a hydroxy group and/or a carboxy group.

The amount of the reactive functional group per 100 g of the (A) copolymer is preferably 0.5 mmol/100 g or more, more preferably 5 mmol/100 g or more, further preferably 10 mmol/100 g or more, particularly preferably 15 mmol/100 g or more. It is preferably 150 mmol/100 g or less, more preferably 100 mmol/100 g or less, further preferably 70 mmol/100 g or less, and particularly preferably 50 mmol/100 g or less. When the amount of the reactive functional group is 0.5 mmol/100 g or more, the durability of the pressure-sensitive adhesive composition is excellent, and when it is 150 mmol/100 g or less, the adhesion to the adherend is excellent.

The copolymer (A) has a reactive functional group. That is, the copolymer (A) contains a structural unit (a-1) having a reactive functional group in its structure. The structural unit (a-1) having the reactive functional group may be only one type, or may have two or more types. The reactive functional group may be contained in either a structural unit derived from a (meth)acrylic monomer (preferably a (meth)acrylate monomer) or a structural unit derived from a vinyl monomer other than the (meth)acrylic monomer. .. That is, the structural unit (a-1) having a reactive functional group is a structural unit derived from a (meth)acrylic monomer (preferably a (meth)acrylate monomer) having a reactive functional group, or a reactive functional group. Structural units derived from vinyl monomers other than the (meth)acrylic monomer having

The content of the structural unit derived from the vinyl monomer having a reactive functional group (structural unit (a-1) having a reactive functional group) in the (A) copolymer is 100% by mass of the entire copolymer. In the above, 0.1% by mass or more is preferable, 0.5% by mass or more is more preferable, 1% by mass or more is further preferable, 3% by mass or more is particularly preferable, 20% by mass or less is preferable, and more preferable. Is 15% by mass or less, more preferably 10% by mass or less, and particularly preferably 8% by mass or less. When the content of the structural unit (a-1) is within the above range, it is possible to obtain a pressure-sensitive adhesive composition having an excellent balance between adhesion to an adherend and durability. The vinyl monomer having a reactive functional group includes vinyl monomers other than the (meth)acrylic monomer having a reactive functional group and the (meth)acrylic monomer having a reactive functional group.

Examples of the (meth)acrylic monomer include (b1) a (meth)acrylic monomer having no reactive functional group and (b2) a (meth)acrylic monomer having a reactive functional group. These monomers may be used alone or in combination of two or more kinds. As the (meth)acrylic monomer having no (b1) reactive functional group, a (meth)acrylate monomer having no (b1-1) reactive functional group is preferable. Examples of (b) the (meth)acrylic monomer having a reactive functional group include (b2-1) a (meth)acrylate monomer having a reactive functional group.

Examples of the (b1) (meth)acrylic monomer having no reactive functional group include (meth)acrylate having a linear alkyl group, (meth)acrylate having a branched alkyl group, and an alkoxy group (meth). ) Acrylate, (meth)acrylate having a polyethylene glycol structural unit, (meth)acrylate having an alicyclic hydrocarbon group, (meth)acrylate having an aromatic group, (meth)acrylate having an oxygen-containing heterocyclic group, three Examples thereof include (meth)acrylates and (meth)acrylamides having a primary amino group. Among these, (meth)acrylates having a linear alkyl group, (meth)acrylates having a branched alkyl group, (meth)acrylates having an alicyclic hydrocarbon group, (meth)acrylates having an aromatic group. , (Meth)acrylamides are preferred.

As the (meth)acrylate having a linear alkyl group, a (meth)acrylate having a linear alkyl group having a linear alkyl group having 1 to 20 carbon atoms is preferable, and a carbon of the linear alkyl group is preferable. (Meth)acrylate having a linear alkyl group whose number is 1 to 10 is more preferable. Examples of the (meth)acrylate having a linear alkyl group include methyl(meth)acrylate, ethyl(meth)acrylate, n-propyl(meth)acrylate, n-butyl(meth)acrylate, n-hexyl(meth)acrylate. , (Meth)acrylic acid linear alkyl esters such as n-octyl (meth)acrylate, n-nonyl (meth)acrylate, decyl (meth)acrylate, n-lauryl (meth)acrylate, and n-stearyl (meth)acrylate Can be mentioned.

As the (meth)acrylate having a branched alkyl group, a (meth)acrylate having a branched alkyl group in which the branched alkyl group has 3 to 20 carbon atoms is preferable, and the carbon of the branched alkyl group is preferably. (Meth)acrylate having a branched alkyl group whose number is 3 to 10 is preferable. Examples of the (meth)acrylate having a branched alkyl group include isopropyl(meth)acrylate, isobutyl(meth)acrylate, sec-butyl(meth)acrylate, tert-butyl(meth)acrylate, isooctyl(meth)acrylate, 2 -(Meth)acrylic acid branched chain alkyl esters such as ethylhexyl (meth)acrylate, isononyl (meth)acrylate, and isodecyl (meth)acrylate.

Examples of the (meth)acrylate having an alkoxy group include (meth)acrylic acid alkoxyalkyl esters such as methoxyethyl (meth)acrylate and ethoxyethyl (meth)acrylate.

Examples of the (meth)acrylate having a polyethylene glycol structural unit include polyethylene glycol (polymerization degree = 1-10 (preferably 1-5)) methyl ether (meth)acrylate, polyethylene glycol (polymerization degree = 1-10 (preferably)). 1-5)) ethyl ether (meth)acrylate, polyethylene glycol (degree of polymerization = 1-10 (preferably 1-5)) propyl ether (meth)acrylate, polypropylene glycol (degree of polymerization = 1-10 (preferably 1-) 5)) Methyl ether (meth)acrylate, polypropylene glycol (degree of polymerization = 1-10 (preferably 1-5)) ethyl ether (meth)acrylate, polypropylene glycol (degree of polymerization = 1-10 (preferably 1-5)) ) Propyl ether (meth)acrylate and the like.

Examples of the alicyclic hydrocarbon group include a saturated monocyclic hydrocarbon group, an unsaturated monocyclic hydrocarbon group, and a bridged ring hydrocarbon group. The (meth)acrylate having an alicyclic hydrocarbon group is preferably a compound in which an alicyclic hydrocarbon group is directly bonded to a (meth)acryloyloxy group. The (meth)acrylate having an alicyclic hydrocarbon group is preferably a (meth)acrylate having a saturated monocyclic hydrocarbon group, and has a saturated monocyclic hydrocarbon group having 6 to 12 carbon atoms (meta). ) Acrylate is more preferred. Examples of the (meth)acrylate having an alicyclic hydrocarbon group include a (meth)acrylate having a saturated monocyclic hydrocarbon group such as cyclohexyl (meth)acrylate, methylcyclohexyl (meth)acrylate and cyclododecyl (meth)acrylate. Bornyl (meth)acrylate, isobornyl (meth)acrylate, 1-adamantyl (meth)acrylate, 2-adamantyl (meth)acrylate, 2-methyl-2-adamantyl (meth)acrylate, 2-ethyl-2-adamantyl (meth ) Acrylate, norbornyl (meth)acrylate, dicyclopentanyl (meth)acrylate, dicyclopentenyl (meth)acrylate and the like (meth)acrylate having a bridged ring hydrocarbon group.

Examples of the (meth)acrylate having an alicyclic hydrocarbon group include (meth)acrylate having a cyclic alkyl group and (meth)acrylate having a polycyclic structure. The (meth)acrylate having a cyclic alkyl group is preferably a (meth)acrylate having a cyclic alkyl group having 6 to 12 carbon atoms in the cyclic alkyl group. Examples of the cyclic alkyl group include a cyclic alkyl group having a monocyclic structure (for example, a cycloalkyl group), and may have a chain portion. Specific examples of the (meth)acrylate having a monocyclic cyclic alkyl group include (meth)acrylic acid cyclic alkyl esters such as cyclohexyl (meth)acrylate, methylcyclohexyl (meth)acrylate, and cyclododecyl (meth)acrylate. be able to.

The (meth)acrylate having a polycyclic structure is preferably a (meth)acrylate having a polycyclic structure having 6 to 12 carbon atoms in the polycyclic structure. Examples of the polycyclic structure include a cyclic alkyl group having a bridged ring structure (for example, an adamantyl group, a norbornyl group, an isobornyl group), and may have a chain portion. Specific examples of the (meth)acrylate having a polycyclic structure include bornyl (meth)acrylate, isobornyl (meth)acrylate, 1-adamantyl (meth)acrylate, 2-adamantyl (meth)acrylate, and 2-methyl-2-. Adamantyl (meth)acrylate, 2-ethyl-2-adamantyl (meth)acrylate, norbornyl (meth)acrylate, dicyclopentanyl (meth)acrylate, dicyclopentenyl (meth)acrylate, dicyclopentanyloxyethyl (meth) Examples thereof include acrylate and dicyclopentenyloxyethyl (meth)acrylate.

The (meth)acrylate having an aromatic group is preferably a (meth)acrylate having an aromatic group having 6 to 12 carbon atoms. Examples of the aromatic group include an aryl group, and may have a chain portion such as an alkylaryl group, an araryl group, and an aryloxyalkyl group. Examples of the (meth)acrylate having an aromatic group include a compound in which an aryl group is directly bonded to a (meth)acryloyloxy group, a compound in which an aralkyl group is directly bonded to a (meth)acryloyloxy group, and a (meth)acryloyloxy group. Examples thereof include compounds in which an alkylaryl group is directly bonded. The aryl group preferably has 6 to 12 carbon atoms. The aralkyl group preferably has 6 to 12 carbon atoms. The alkylaryl group preferably has 6 to 12 carbon atoms. Examples of the (meth)acrylate having an aromatic group include benzyl (meth)acrylate, phenyl (meth)acrylate, and phenoxyethyl (meth)acrylate.

The (meth)acrylate having an oxygen-containing heterocyclic group is preferably a (meth)acrylate having a 4-membered to 6-membered oxygen-containing heterocyclic group. Specific examples of the (meth)acrylate having an oxygen-containing heterocyclic group include tetrahydrofurfuryl (meth)acrylate, (3-ethyloxetan-3-yl)methyl (meth)acrylate, (2-methyl-2-ethyl-). 1,3-dioxolan-4-yl)methyl(meth)acrylate, cyclic trimethylolpropane formal(meth)acrylate, 2-[(2-tetrahydropyranyl)oxy]ethyl(meth)acrylate, 1,3-dioxane- (Meth)acrylate etc. are mentioned.

Examples of the (meth)acrylate having a tertiary amino group include 2-(dimethylamino)ethyl(meth)acrylate and N,N-dimethylaminopropyl(meth)acrylate.

Examples of the (meth)acrylamides include N,N-dimethyl(meth)acrylamide, N,N-diethyl(meth)acrylamide, N,N-diisopropyl(meth)acrylamide, (meth)acrylamide, N-methyl(meth). Acrylamide, N-ethyl(meth)acrylamide, N-isopropyl(meth)acrylamide, N-tert-butyl(meth)acrylamide, N-octyl(meth)acrylamide, N-methoxymethyl(meth)acrylamide, N-ethoxymethyl( Examples thereof include meth)acrylamide, N-propoxymethyl(meth)acrylamide, N-butoxymethyl(meth)acrylamide, diacetone acrylamide, N-(meth)acryl morpholine. The (meth)acrylamides are (meth)acrylic monomers, but are not included in the (meth)acrylate monomers.

As the (b2) (meth)acrylic monomer having a reactive functional group, a (meth)acrylic monomer having a hydroxy group (preferably (meth)acrylate monomer) and a (meth)acrylic monomer having a carboxy group (preferably (( (Meth)acrylate monomer), (meth)acrylic monomer having sulfonic acid group (preferably (meth)acrylate monomer), (meth)acrylic monomer having phosphoric acid group (preferably (meth)acrylate monomer), having epoxy group Examples thereof include (meth)acrylic monomers (preferably (meth)acrylate monomers). Among these, a (meth)acrylic monomer having a hydroxy group and a (meth)acrylic monomer having a carboxy group are preferable.

Examples of the (meth)acrylic monomer having a hydroxy group include 2-hydroxyethyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, 6 -Hydroxyhexyl (meth)acrylate, 8-hydroxyoctyl (meth)acrylate, hydroxyalkyl (meth)acrylate such as 10-hydroxydecyl (meth)acrylate, 12-hydroxylauryl (meth)acrylate; (4-hydroxymethylcyclohexyl) Examples thereof include hydroxyalkyl cycloalkane (meth)acrylates such as methyl (meth)acrylate; caprolactone adducts of hydroxyalkyl (meth)acrylate; and the like. Among these, hydroxyalkyl (meth)acrylate is preferable, and (meth)acrylate having a hydroxyalkyl group having 1 to 5 carbon atoms is more preferable.

Examples of the (meth)acrylic monomer having a carboxy group include carboxyethyl (meth)acrylate, carboxypentyl (meth)acrylate, 2-(meth)acryloyloxyethyl succinate, 2-(meth)acryloyloxyethyl maleate, 2 -(Meth)acryloyloxyethyl phthalate and other hydroxy group-containing (meth)acrylates are reacted with acid anhydrides such as maleic anhydride, succinic anhydride and phthalic anhydride, and (meth)acrylic acid. .. Among these, (meth)acrylic acid is preferable.

Examples of the (meth)acrylic monomer having a sulfonic acid group include ethyl (meth)acrylate sulfonate.

Examples of the (meth)acrylic monomer having a phosphoric acid group include 2-(phosphonooxy)ethyl (meth)acrylate.

Examples of the (meth)acrylic acid ester having an epoxy group include glycidyl (meth)acrylate and 3,4-epoxycyclohexylmethyl (meth)acrylate.

Examples of the vinyl monomer of the (meth)acrylic monomer include (b3) vinyl monomers other than (meth)acrylic monomers having no reactive functional group and (b4) vinyl other than (meth)acrylic monomers having reactive functional groups. Examples include monomers. These monomers may be used alone or in combination of two or more kinds.

As the vinyl monomer other than the (b3) (meth)acrylic monomer having no reactive functional group, an aromatic vinyl monomer, a vinyl monomer containing a hetero ring, a vinyl carboxylate, a vinyl monomer containing a tertiary amino group. , Vinyl monomers containing quaternary ammonium base, vinylamides, α-olefins, dienes and the like.

Examples of the aromatic vinyl monomer include styrene, α-methylstyrene, 4-methylstyrene, 2-methylstyrene, 3-methylstyrene, 4-methoxystyrene, 2-hydroxymethylstyrene and 1-vinylnaphthalene.
Examples of the vinyl monomer containing a heterocycle include 2-vinylthiophene, N-methyl-2-vinylpyrrole, 2-vinylpyridine, 4-vinylpyridine and the like.
Examples of the vinyl carboxylate include vinyl acetate, vinyl pivalate, vinyl benzoate and the like.
Examples of the vinyl monomer having a tertiary amino group include N,N-dimethylallylamine.
Examples of the vinyl monomer containing a quaternary ammonium salt group include N-methacryloylaminoethyl-N,N,N-dimethylbenzylammonium chloride.
Examples of the vinylamides include N-vinylformamide, N-vinylacetamide, 1-vinyl-2-pyrrolidone, N-vinyl-ε-captralactam and the like.
Examples of the α-olefin include 1-hexene, 1-octene, 1-decene and the like.
Examples of the dienes include butadiene, isoprene, 4-methyl-1,4-hexadiene, and 7-methyl-1,6-octadiene.

Examples of the vinyl monomer other than the (b4) (meth)acrylic monomer having a reactive functional group include a vinyl monomer having a hydroxy group, a vinyl monomer having a carboxy group, and a vinyl monomer having an epoxy group.

Examples of the vinyl monomer having a hydroxy group include p-hydroxystyrene and allyl alcohol.
Examples of the vinyl monomer having a carboxy group include crotonic acid, maleic acid, itaconic acid, citraconic acid, cinnamic acid and (meth)acrylic acid.
Examples of the vinyl monomer containing an epoxy group include 2-allyloxirane, glycidyl vinyl ether, and 3,4-epoxycyclohexyl vinyl ether.

The (A) copolymer may be any of a random copolymer, a block copolymer, a graft copolymer and the like.

The weight average molecular weight (Mw) of the (A) copolymer is 200,000 or more, preferably 400,000 or more, more preferably 500,000 or more, further preferably 600,000 or more, and 2 million or less, preferably It is 1.8 million or less, more preferably 1.5 million or less, and further preferably 1.3 million or less. If the Mw of the (A) copolymer is less than 200,000, the cohesive force may be insufficient and the heat resistance may decrease, or the surface of the adherend may be contaminated. If it exceeds 2 million, the coating workability of the pressure-sensitive adhesive composition may be reduced. May get worse. The method for measuring the weight average molecular weight (Mw) will be described later.

The molecular weight distribution (PDI) of the (A) copolymer is less than 3.0, preferably less than 2.5, more preferably less than 2.4, and particularly preferably less than 2.0. The smaller the PDI is, the narrower the molecular weight distribution becomes, and the copolymer has a uniform molecular weight. When the value is 1.0, the molecular weight distribution is the narrowest. When the PDI is less than 3.0, the content of the one having a small molecular weight or the one having a large molecular weight is lower than the designed molecular weight of the copolymer, and the adhesive strength is improved. In the present invention, the molecular weight distribution (PDI) is a value calculated by (weight average molecular weight (Mw))/(number average molecular weight (Mn)), and a method for measuring Mw and Mn will be described later.

The glass transition temperature (Tg) of the (A) copolymer is preferably −80° C. or higher, more preferably −70° C. or higher, preferably 20° C. or lower, more preferably 0° C. or lower. When the glass transition temperature is -80°C or higher, the pressure-sensitive adhesive composition is given sufficient cohesive force to improve the durability of the pressure-sensitive adhesive layer, and when it is 20°C or lower, the adhesiveness of the pressure-sensitive adhesive layer to the supporting substrate is high. It becomes higher, peeling is suppressed, and durability is improved.

The glass transition temperature (Tg) of the (A) copolymer is a value calculated by the following FOX equation (Equation (1)). In Formula (1), Tg represents the glass transition temperature (° C.) of the copolymer. Tgi represents the glass transition temperature (° C.) when the vinyl monomer i forms a homopolymer. Wi represents the mass ratio of the vinyl monomer i in all the vinyl monomers forming the copolymer, and ΣWi=1. i is a natural number of 1 to n.

Table 1 shows the glass transition temperatures of representative homopolymers.

The (A) copolymer is produced by radical polymerization of a vinyl monomer by a living radical polymerization method. In the conventional radical polymerization method (free radical polymerization method), not only the initiation reaction and the growth reaction but also the termination reaction and the chain transfer reaction cause the deactivation of the growth end, resulting in a mixture of polymers with various molecular weights and heterogeneous compositions. Tends to be easy. The living radical polymerization method, while maintaining the simplicity and versatility of the conventional radical polymerization method, a termination reaction, or chain transfer hardly occurs, because the growth end grows without deactivation, precise control of the molecular weight distribution, It is easy to produce a polymer having a uniform composition.

Therefore, it is considered that the copolymer produced by the living radical polymerization method has an advantage that the low molecular weight component (oligomer) is small and the adherend is less contaminated when used in the pressure-sensitive adhesive composition. Incidentally, since the reactive functional group is uniformly distributed in the copolymer, the copolymer produced by the living radical polymerization method is better than the copolymer produced by the free radical polymerization method, with the isocyanate cross-linking agent. It is considered that the amount of the reactive functional group capable of reacting increases, the crosslinking is delayed, and a long curing period is required.

In the living radical polymerization method, a random copolymer can be obtained by using a mixture of each monomer (vinyl monomer) constituting the (A) copolymer. Further, it is also possible to form a block copolymer by sequentially reacting the vinyl monomers constituting the copolymer. For example, in the case of a diblock copolymer, a method in which the first block is produced first, and then the vinyl monomer constituting the second block is polymerized in the first block; the second block is produced first. , A method of polymerizing a vinyl monomer forming the first block in the second block; and the like. In the case of a triblock copolymer, the first block is first produced, the first block is polymerized with the vinyl monomer constituting the second block, and the vinyl monomer constituting the third block is further polymerized. And a method of polymerizing the above.

In the living radical polymerization method, a method of using a transition metal catalyst such as copper, ruthenium, nickel, iron, etc. (ATRP method) depending on the difference in the method of stabilizing the polymerization growth terminal (ATRP method); a method of using a sulfur-based reversible chain transfer agent (RAFT method); there is a method using an organic tellurium compound (TERP method) and the like. Since the ATRP method uses an amine-based complex, it cannot be used unless the acidic group of the vinyl monomer having an acidic group is protected. In the RAFT method, when various kinds of vinyl monomers are used, it may be difficult to have a low molecular weight distribution, and there may be problems such as sulfur smell and coloring. Among these methods, it is preferable to use the TERP method from the viewpoint of diversity of usable vinyl monomers, control of molecular weight in the polymer region, uniform composition, or coloring.

The TERP method is a method in which an organic tellurium compound is used as a chain transfer agent to polymerize a radically polymerizable compound (vinyl monomer), and for example, WO 2004/14848, WO 2004/14962, and WO 2004/14962. The method described in WO 2004/072126 and WO 2004/096870.

Specific polymerization methods of the TERP method include the following (a) to (d).
(A) A method of polymerizing a vinyl monomer using an organic tellurium compound represented by the formula (1).
(B) A method of polymerizing a vinyl monomer using a mixture of an organic tellurium compound represented by the formula (1) and an azo-based polymerization initiator.
(C) A method of polymerizing a vinyl monomer using a mixture of an organic tellurium compound represented by the formula (1) and an organic ditelluride compound represented by the formula (2).
(D) A method of polymerizing a vinyl monomer using a mixture of an organic tellurium compound represented by the formula (1), an azo polymerization initiator and an organic ditelluride compound represented by the formula (2).

［式（１）において、Ｒ¹は、炭素数１〜８のアルキル基、アリール基または芳香族ヘテロ環基である。Ｒ²およびＲ³は、それぞれ独立に、水素原子または炭素数１〜８のアルキル基である。Ｒ⁴は、炭素数１〜８のアルキル基、アリール基、置換アリール基、芳香族ヘテロ環基、アルコキシ基、アシル基、アミド基、オキシカルボニル基、シアノ基、アリル基またはプロパルギル基である。］

[In the formula (1), R ¹ is an alkyl group having 1 to 8 carbon atoms, an aryl group or an aromatic heterocyclic group. R ² and R ³ are each independently a hydrogen atom or an alkyl group having 1 to 8 carbon atoms. R ⁴ is an alkyl group having 1 to 8 carbon atoms, an aryl group, a substituted aryl group, an aromatic heterocyclic group, an alkoxy group, an acyl group, an amide group, an oxycarbonyl group, a cyano group, an allyl group or a propargyl group. ]

［式（２）において、Ｒ¹は、炭素数１〜８のアルキル基、アリール基または芳香族ヘテロ環基である。］

[In the formula (2), R ¹ is an alkyl group having 1 to 8 carbon atoms, an aryl group or an aromatic heterocyclic group. ]

The group represented by R ¹ is an alkyl group having 1 to 8 carbon atoms, an aryl group or an aromatic heterocyclic group, and is specifically as follows.
Examples of the alkyl group having 1 to 8 carbon atoms include methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group, sec-butyl group, tert-butyl group, pentyl group, hexyl group and heptyl group. Examples thereof include linear or branched alkyl groups such as groups and octyl groups, and cyclic alkyl groups such as cyclohexyl groups. It is preferably a linear or branched alkyl group having 1 to 4 carbon atoms, and more preferably a methyl group or an ethyl group.
Examples of the aryl group include a phenyl group and a naphthyl group.
Examples of the aromatic heterocyclic group include a pyridyl group, a furyl group and a thienyl group.

The groups represented by R ² and R ³ are each independently a hydrogen atom or an alkyl group having 1 to 8 carbon atoms, and each group is specifically as follows.
Examples of the alkyl group having 1 to 8 carbon atoms include methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group, sec-butyl group, tert-butyl group, pentyl group, hexyl group, heptyl group. Examples thereof include linear or branched alkyl groups such as groups and octyl groups, and cyclic alkyl groups such as cyclohexyl groups. It is preferably a linear or branched alkyl group having 1 to 4 carbon atoms, and more preferably a methyl group or an ethyl group.

The group represented by R ⁴ is an alkyl group having 1 to 8 carbon atoms, an aryl group, a substituted aryl group, an aromatic heterocyclic group, an alkoxy group, an acyl group, an amide group, an oxycarbonyl group, a cyano group, an allyl group or It is a propargyl group and is specifically as follows.
Examples of the alkyl group having 1 to 8 carbon atoms include methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group, sec-butyl group, tert-butyl group, pentyl group, hexyl group, heptyl group. Group, a linear or branched alkyl group such as an octyl group, and a cyclic alkyl group such as a cyclohexyl group. It is preferably a linear or branched alkyl group having 1 to 4 carbon atoms, and more preferably a methyl group or an ethyl group.
Examples of the aryl group include a phenyl group and a naphthyl group. A phenyl group is preferred.
Examples of the substituted aryl group include a phenyl group having a substituent and a naphthyl group having a substituent. Examples of the substituent of the aryl group having a substituent include a halogen atom, a hydroxy group, an alkoxy group, an amino group, a nitro group, a cyano group, and a carbonyl-containing group represented by -COR ⁴¹ (R ⁴¹ is a carbon number. Examples thereof include an alkyl group having 1 to 8, an aryl group, an alkoxy group having 1 to 8 carbon atoms or an aryloxy group), a sulfonyl group, and a trifluoromethyl group. Further, these substituents are preferably substituted by one or two.
Examples of the aromatic heterocyclic group include a pyridyl group, a furyl group and a thienyl group.
The alkoxy group is preferably a group in which an alkyl group having 1 to 8 carbon atoms is bonded to an oxygen atom, and examples thereof include a methoxy group, an ethoxy group, a propoxy group, an isopropoxy group, an n-butoxy group, a sec-butoxy group and a tet- group. Examples thereof include butoxy group, pentyloxy group, hexyloxy group, heptyloxy group, octyloxy group and the like.
Examples of the acyl group include an acetyl group, a propionyl group and a benzoyl group.
Examples of the amide group include -CONR ⁴²¹ R ⁴²² (R ⁴²¹ and R ⁴²² are each independently a hydrogen atom, an alkyl group having 1 to 8 carbon atoms or an aryl group).
The oxycarbonyl group is preferably a group represented by —COOR ⁴³ (R ⁴³ is a hydrogen atom, an alkyl group having 1 to 8 carbon atoms or an aryl group), and examples thereof include a carboxy group, a methoxycarbonyl group, an ethoxycarbonyl group, and propoxycarbonyl. Group, n-butoxycarbonyl group, sec-butoxycarbonyl group, ter-butoxycarbonyl group, n-pentoxycarbonyl group, phenoxycarbonyl group and the like. Preferred oxycarbonyl groups include methoxycarbonyl group and ethoxycarbonyl group.
As the allyl group, -CR ⁴⁴¹ R ⁴⁴² -CR ⁴⁴³ =CR ⁴⁴⁴ R ⁴⁴⁵ (R ⁴⁴¹ and R ⁴⁴² are each independently a hydrogen atom or an alkyl group having 1 to 8 carbon atoms, R ⁴⁴³ , R ⁴⁴⁴ and R ⁴⁴⁵ are , Each independently a hydrogen atom, an alkyl group having 1 to 8 carbon atoms or an aryl group, and each substituent may be connected by a cyclic structure).
Examples of the propargyl group include -CR ⁴⁵¹ R ⁴⁵² -C≡CR ⁴⁵³ (R ⁴⁵¹ and R ⁴⁵² are hydrogen atoms or an alkyl group having 1 to 8 carbon atoms, R ⁴⁵³ is a hydrogen atom, an alkyl group having 1 to 8 carbon atoms. , Aryl groups or silyl groups).

The organic tellurium compound represented by the formula (1) is specifically (methylteranylmethyl)benzene, (methylteranylmethyl)naphthalene, ethyl-2-methyl-2-methylteranyl-propionate, ethyl-2-methyl. -2-n-butylteranyl-propionate, (2-trimethylsiloxyethyl)-2-methyl-2-methylteranyl-propionate, (2-hydroxyethyl)-2-methyl-2-methylteranyl-propionate or (3-trimethylsilylpropargyl) 2-methyl-2-methylteranyl-propionate, etc., organic tellurium described in WO 2004/14848, WO 2004/14962, WO 2004/072126, and WO 2004/096870. All of the compounds can be exemplified.

Specific examples of the organic ditelluride compound represented by the formula (2) include dimethylditelluride, diethylditelluride, di-n-propylditelluride, diisopropylditelluride, dicyclopropylditelluride, and dicyclohexylditelluride. -N-butyl ditelluride, di-s-butyl ditelluride, di-t-butyl ditelluride, dicyclobutyl ditelluride, diphenyl ditelluride, bis-(p-methoxyphenyl) ditelluride, bis-(p-aminophenyl) ditelluride, bis Examples thereof include -(p-nitrophenyl) ditelluride, bis-(p-cyanophenyl) ditelluride, bis-(p-sulfonylphenyl) ditelluride, dinaphthyl ditelluride, dipyridyl ditelluride, and the like.

The azo-based polymerization initiator can be used without particular limitation as long as it is an azo-based polymerization initiator used in ordinary radical polymerization. For example, 2,2'-azobis(isobutyronitrile) (AIBN), 2,2'-azobis(2-methylbutyronitrile) (AMBN), 2,2'-azobis(2,4-dimethylvaleronitrile) (ADVN), 1,1′-azobis(1-cyclohexanecarbonitrile) (ACHN), dimethyl-2,2′-azobisisobutyrate (MAIB), 4,4′-azobis(4-cyanovalerianic acid) (ACVA), 1,1′-azobis(1-acetoxy-1-phenylethane), 2,2′-azobis(2-methylbutyramide), 2,2′-azobis(4-methoxy-2,4-). Dimethylvaleronitrile) (V-70), 2,2'-azobis(2-methylamidinopropane) dihydrochloride, 2,2'-azobis[2-(2-imidazolin-2-yl)propane], 2, 2'-azobis[2-methyl-N-(2-hydroxyethyl)propionamide], 2,2'-azobis(2,4,4-trimethylpentane), 2-cyano-2-propylazoformamide, 2, Examples thereof include 2'-azobis(N-butyl-2-methylpropionamide), 2,2'-azobis(N-cyclohexyl-2-methylpropionamide), and the like.

In the polymerization step, in a container replaced with an inert gas, a vinyl monomer and an organic tellurium compound of the formula (1) are added to the azo compound for the purpose of promoting the reaction, controlling the molecular weight and the molecular weight distribution according to the type of the vinyl monomer. A system polymerization initiator and/or an organic ditelluride compound of formula (2) are mixed. At this time, examples of the inert gas include nitrogen, argon, and helium. Argon and nitrogen are preferable.

In the polymerization methods (a), (b), (c) and (d), the amount of the vinyl monomer used may be appropriately adjusted depending on the physical properties, molecular weight and the like of the target copolymer. It is preferable that the vinyl monomer is 200 mol to 30000 mol per 1 mol of the organic tellurium compound of (1). The molecular weight of the target copolymer can be increased by increasing the amount of the vinyl monomer used per 1 mol of the organic tellurium compound of the formula (1).

When the organic tellurium compound of the formula (1) and the azo-based polymerization initiator are used in combination in the polymerization method of the above (b), the amount of the azo-based polymerization initiator to be used is usually the organic tellurium compound of the formula (1). It is preferable that the amount of the azo polymerization initiator is 0.01 mol to 10 mol per 1 mol.

When the organic telluride compound of the formula (1) and the organic ditelluride compound of the formula (2) are used in combination in the polymerization method of the above (c), the amount of the organic ditelluride compound of the formula (2) to be used is usually represented by the formula ( It is preferable that the amount of the organic ditelluride compound of the formula (2) is 0.01 mol to 100 mol with respect to 1 mol of the organic tellurium compound of 1).

When the organic tellurium compound of the formula (1), the organic ditelluride compound of the formula (2) and the azo-based polymerization initiator are used in combination in the polymerization method of the above (d), the amount of the azo-based polymerization initiator to be used is usually It is preferable that the amount of the azo polymerization initiator is 0.01 mol to 100 mol with respect to a total of 1 mol of the organic tellurium compound of the formula (1) and the organic ditelluride compound of the formula (2).

The polymerization reaction can be carried out without a solvent, but may be carried out by stirring the mixture using an aprotic solvent or a protic solvent generally used in radical polymerization. The aprotic solvent that can be used is, for example, benzene, toluene, N,N-dimethylformamide (DMF), dimethylsulfoxide (DMSO), acetone, 2-butanone (methyl ethyl ketone), dioxane, propylene glycol monomethyl ether acetate, chloroform, tetrachloromethane, tetrachloromethane, tetrachloromethane, tetrachloromethane, tetrachloromethane, tetrachlorobenzene Examples thereof include carbon chloride, tetrahydrofuran (THF), ethyl acetate, propylene glycol monomethyl ether acetate, trifluoromethylbenzene and the like. Examples of the protic solvent include water, methanol, ethanol, isopropanol, n-butanol, ethyl cellosolve, butyl cellosolve, 1-methoxy-2-propanol or diacetone alcohol, hexafluoroisopropanol and the like.

The amount of the solvent used may be appropriately adjusted, and for example, it is preferably 0.01 ml or more, more preferably 0.05 ml or more, still more preferably 0.1 ml or more, and 50 ml or less with respect to 1 g of the vinyl monomer. It is preferably 10 ml or less, more preferably 1 ml or less.

Then, the mixture is stirred. The reaction temperature and the reaction time may be appropriately adjusted depending on the molecular weight or the molecular weight distribution of the obtained copolymer, but the stirring is usually performed at 0°C to 150°C for 1 minute to 100 hours. The TERP method can obtain a high yield and a precise molecular weight distribution even at a low polymerization temperature and a short polymerization time. At this time, the pressure is usually atmospheric pressure, but may be increased or decreased.

After the completion of the polymerization reaction, the reaction mixture obtained is subjected to removal of the solvent used, the residual vinyl monomer, and the like by a usual isolation and purification means, whereby the desired copolymer can be isolated and purified. The reaction mixture may be used as it is in the pressure-sensitive adhesive composition as long as the physical properties of the pressure-sensitive adhesive composition are not impaired.

The growth end of the copolymer obtained by the polymerization reaction is in the form of -TeR ¹ (wherein R ¹ is the same as above), and is deactivated by the operation in air after the completion of the polymerization reaction. , Tellurium atoms may remain. It is preferable to remove the tellurium atom because the copolymer having the tellurium atom remaining at the terminal becomes colored and has poor thermal stability.

As a method of removing the tellurium atom, a radical reduction method using tributylstannane or a thiol compound; a method of adsorbing with activated carbon, silica gel, activated alumina, activated clay, molecular sieves and a polymeric adsorbent; an ion exchange resin, etc. Method of adsorbing metal; hydrogen peroxide water or peroxide such as benzoyl peroxide is added, or air or oxygen is blown into the system to oxidize and decompose the tellurium atom at the terminal of the copolymer, and then washing with water or an appropriate method A liquid-liquid extraction method or a solid-liquid extraction method that removes residual tellurium compounds by combining solvents; a purification method in a solution state such as ultrafiltration that extracts and removes only those having a specific molecular weight or less can be used. Also, these methods can be used in combination. In the copolymer produced by the TERP method, the metal compound derived from the chain transfer agent may remain as an impurity (more than 0 ppm). The content of tellurium in the copolymer produced by the TERP method is preferably 1000 ppm or less, more preferably 400 ppm or less, and further preferably 200 ppm or less.

((B) isocyanate crosslinking agent)
The pressure-sensitive adhesive composition contains (B) an isocyanate-based crosslinking agent. The isocyanate-based crosslinking agent is a compound having two or more isocyanate groups in one molecule (including an isocyanate-regenerated functional group in which an isocyanate group is temporarily protected by a blocking agent or quantification). The (B) isocyanate crosslinking agent may be used alone or in combination of two or more kinds.

Examples of the isocyanate cross-linking agent include aromatic isocyanates such as tolylene diisocyanate and xylene diisocyanate, alicyclic isocyanates such as isophorone diisocyanate, and aliphatic isocyanates such as hexamethylene diisocyanate.
More specifically, for example, lower aliphatic polyisocyanates such as butylene diisocyanate and hexamethylene diisocyanate; cyclopentylene diisocyanate, cyclohexylene diisocyanate, alicyclic isocyanates such as isophorone diisocyanate; 2,4-tolylene diisocyanate, Aromatic diisocyanates such as 4,4′-diphenylmethane diisocyanate, xylylene diisocyanate and polymethylene polyphenyl isocyanate; trimethylolpropane/tolylene diisocyanate trimer adduct, trimethylolpropane/hexamethylene diisocyanate trimer adduct, Isocyanate adducts of hexamethylene diisocyanate such as isocyanurates; trimethylol propane adducts of xylylene diisocyanate; trimethylol propane adducts of hexamethylene diisocyanate; polyether polyisocyanates, polyester polyisocyanates, and these and various polyols One or more selected from adducts, polyisocyanates polyfunctionalized with isocyanurate bonds, burette bonds, allophanate bonds and the like can be used. Of these, it is preferable to use an aliphatic isocyanate because the reaction rate is high.

The content of the (B) isocyanate crosslinking agent in the pressure-sensitive adhesive composition is preferably 0.01 parts by mass or more, more preferably 0.1 parts by mass or more, relative to 100 parts by mass of the (A) copolymer. It is more preferably 1 part by mass or more, preferably 20 parts by mass or less, more preferably 15 parts by mass or less, and further preferably 10 parts by mass or less. When the content of the cross-linking agent is low, the cohesive force is insufficient, and when the content of the cross-linking agent is too high, the cross-linking density becomes too high and the adhesive strength is lowered, which is not preferable.

In the pressure-sensitive adhesive composition, the molar ratio of the isocyanate group of the (B) isocyanate cross-linking agent to the reactive functional group of the (A) copolymer (molar amount of isocyanate group/molar amount of reactive functional group) is , 0.001 or more, more preferably 0.01 or more, further preferably 0.1 or more, and 10 or less, more preferably 5 or less, still more preferably 2 or less.

((C) Metal chelate compound)
The pressure-sensitive adhesive composition contains (C) a metal chelate compound. This makes it possible to shorten the curing time in the formation of the pressure-sensitive adhesive composition, and prevent the resulting pressure-sensitive adhesive film from undergoing heavy peeling. The (C) metal chelate compound is a complex in which a ligand having two or more coordination atoms forms a ring and is bound to a central metal. The (C) metal chelate compounds may be used alone or in combination of two or more.

The metal constituting the (C) metal chelate compound is, for example, one selected from aluminum, zirconium, titanium, zinc, barium, calcium, copper, strontium, chromium, cobalt, iron, indium, magnesium, manganese and nickel. Alternatively, two or more kinds of metal atoms may be mentioned. Among these, at least one metal atom selected from aluminum, zirconium, titanium and zinc is preferable. The (C) metal chelate compound preferably does not contain tin as a constituent metal.

In the (C) metal chelate compound, the coordination number can be selected in an appropriate range in consideration of the type of metal atom used and the intended effect, and is not particularly limited. In the (C) metal chelate compound, the coordination number of the metal atom can be 3 to 20, preferably 4 to 16. In the present invention, the “coordination number” refers to the number of coordination bonds formed between the metal atom and the ligand.

Examples of the ligand (chelating agent) constituting the (C) metal chelate compound include polyaminocarboxylic acids, oxycarboxylic acids, condensed phosphates and the like. The (C) metal chelate compound preferably contains a ligand represented by the following formula (3).

［式中、Ｒ¹¹およびＲ¹²は、それぞれ独立に、水素、アルキル基またはアルコキシ基を示す。］

[In the formula, R ¹¹ and R ¹² each independently represent hydrogen, an alkyl group, or an alkoxy group. ]

The alkyl group represented by R ¹¹ or R ¹² is preferably an alkyl group having 1 to 8 carbon atoms. Examples of the alkyl group having 1 to 8 carbon atoms include methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group, sec-butyl group, tert-butyl group, pentyl group, hexyl group and heptyl group. Group, a linear or branched alkyl group such as an octyl group, and a cyclic alkyl group such as a cyclohexyl group. It is preferably a linear or branched alkyl group having 1 to 4 carbon atoms, and more preferably a methyl group or an ethyl group.

The alkoxy group represented by R ¹¹ or R ¹² is preferably a group in which an alkyl group having 1 to 8 carbon atoms is bonded to an oxygen atom, and examples thereof include a methoxy group, an ethoxy group, a propoxy group, an isopropoxy group, and n-butoxy group. Group, sec-butoxy group, tet-butoxy group, pentyloxy group, hexyloxy group, heptyloxy group, octyloxy group and the like.

Examples of the ligand contained in the (C) metal chelate compound include, for example, acetylacetonate-based ligands, acetoacetate-based ligands, acetonate-based ligands, lactate-based ligands, and carboxylic acid-based coordinations. Child, citrate-based ligand, glycol-based ligand and the like. Specific examples include, for example, acetylacetonate, alkylacetoacetate, alkylenediaminetetraacetate, diisoalkoxybisalkylacetoacetate, diisopropoxybisalkylacetoacetate, di-n-alkoxy-bisalkyl-acetoacetate, hydroxyalkylene. Examples thereof include diamine triacetate.

Specific examples of the (C) metal chelate compound include zirconium tetraacetylacetonate, zirconium tributoxymonoacetylacetonate, zirconium monobutoxyacetylacetonate bis(ethylacetoacetate), zirconium dibutoxybis(ethylacetoacetate), and the like. Zirconium chelate compounds: titanium ethylacetoacetate, titanium diisopropoxybis(acetylacetonate), titanium tetraacetylacetonate, titanium diisopropoxybis(ethylacetoacetate) and other titanium chelate compounds; aluminum tris(acetylacetonate) Aluminum chelate compounds such as aluminum bisethylacetoacetate monoacetylacetonate, aluminum tris(ethylacetoacetate), aluminum ethylacetoacetate diisopropylate, aluminum alkylacetoacetate diisopropylate; zinc (II) bisacetylacetonate Zinc chelate compounds such as hydrates; barium chelate compounds such as bis(acetylacetonate)diaqua barium (II); calcium chelate compounds such as bis(acetylacetonate)diaqua calcium (II); copper (II) bis Copper chelate compounds such as acetylacetonate; Strontium chelate compounds such as bis(acetylacetonate)diaquastrontium (II); Chromium chelate compounds such as chromium tris (acetylacetonate); Cobalt (III) tris (acetylacetonate); Cobalt chelate compounds such as bis(acetylacetonate)diaquacobalt(II); iron chelate compounds such as iron(III) tris(acetylacetonate), bis(acetylacetonate)diaquairon(II); indium tris(acetyl) Acetonate) and other indium chelate compounds; bis(acetylacetonate)diaquamagnesium (II) and other magnesium chelate compounds; bis(acetylacetonate)diaquamanganese (II) and other manganese chelate compounds; nickel (II) bis Examples include nickel chelate compounds such as acetylacetonate dihydrate. Among these, zirconium chelate compounds and titanium chelate compounds are preferable.

The content of the (C) metal chelate compound in the pressure-sensitive adhesive composition of the present invention is preferably 0.01 parts by mass or more, and more preferably 0.02 parts by mass, relative to 100 parts by mass of the (A) copolymer. As described above, the content is more preferably 0.04 parts by mass or more and 0.5 parts by mass or less, more preferably 0.4 parts by mass or less, and further preferably 0.3 parts by mass or less. By setting the content of the metal chelate compound (C) within the above range, it becomes possible to obtain an excellent effect of promoting crosslinking and an effect of suppressing heavy exfoliation.

Here, when the pressure-sensitive adhesive composition contains a metal compound derived from the chain transfer agent used in the living radical polymerization, it is considered that the metal compound acts on the adherend to cause heavy exfoliation. In the pressure-sensitive adhesive composition of the present invention, heavy peeling can be suppressed by containing the (C) metal chelate compound. The metal compound derived from the chain transfer agent differs depending on the living radical polymerization method, and examples thereof include a tellurium compound in the case of the TERP method, and a copper compound, a ruthenium compound, a nickel compound, an iron compound in the case of the ATRP method.

When the chain transfer agent-derived metal compound is contained in the (A) copolymer, the content of the (C) metal chelate compound in the pressure-sensitive adhesive composition is the chain contained in the (A) copolymer. It is preferably 2 parts by mass or more, more preferably 2.5 parts by mass or more, still more preferably 4 parts by mass or more, and 40 parts by mass or less based on 1 part by mass of the metal compound of the transfer agent. , More preferably 35 parts by mass or less, further preferably 30 parts by mass or less. Heavy exfoliation can be suppressed by adjusting the mass ratio of the metal compound derived from the chain transfer agent and the (C) metal chelate compound.

In the pressure-sensitive adhesive composition of the present invention, by mixing the (C) metal chelate compound, the reaction between the reactive functional group of the (A) copolymer and the (B) isocyanate crosslinking agent can be promoted. Therefore, the pressure-sensitive adhesive composition of the present invention can shorten the curing period at the time of forming the adhesive layer without blending the organotin compound. Therefore, the content of the organotin compound in the pressure-sensitive adhesive composition of the present invention is 3% by mass or less, more preferably 1% by mass or less, and further preferably 0.5% by mass or less. The pressure-sensitive adhesive composition of the present invention preferably contains no organotin compound. The organotin compound is used as a crosslinking accelerator, and examples thereof include dibutyltin laurate and dibutyltin dioctylate.

(Other additives)
In the pressure-sensitive adhesive composition of the present invention, other additives can be blended and used in addition to the (A) copolymer, (B) isocyanate cross-linking agent, and (C) metal chelate compound. Examples of other additives include the following.

The pressure-sensitive adhesive composition may be mixed with (D) a crosslinking retarder, if necessary. In the pressure-sensitive adhesive composition containing an isocyanate-based cross-linking agent, the above-mentioned (D) cross-linking retarder can block an excessive viscosity increase of the pressure-sensitive adhesive composition by blocking an isocyanate group of the cross-linking agent. It is a compound. The type of the (D) crosslinking retarder is not particularly limited, but examples thereof include β-such as acetylacetone, hexane-2,4-dione, heptane-2,4-dione, and octane-2,4-dione. Diketones; β-ketoesters such as methyl acetoacetate, ethyl acetoacetate, propyl acetoacetate, butyl acetoacetate, octyl acetoacetate, oleyl acetoacetate, lauryl acetoacetate and stearyl acetoacetate; benzoylacetone and the like can be used. .. As the (D) crosslinking retarder, those capable of acting as a chelating agent are preferable, and β-diketones and β-ketoesters are preferable.

The content of the (D) cross-linking retarder that can be blended in the pressure-sensitive adhesive composition is preferably 1 part by mass or more, more preferably 2 parts by mass or more, based on 100 parts by mass of the (A) copolymer. The amount is preferably 3 parts by mass or more, preferably 40 parts by mass or less, more preferably 30 parts by mass or less, and further preferably 15 parts by mass or less. By adjusting the content of the (D) cross-linking retarder within the above range, an excessive increase in viscosity or gelation of the pressure-sensitive adhesive composition can be achieved after blending the (B) isocyanate cross-linking agent into the pressure-sensitive adhesive composition. It is possible to suppress and extend the storage stability (pot life) of the pressure-sensitive adhesive composition.

When a compound acting as a chelating agent is used as the (D) crosslinking retardant, the metal component of the metal compound derived from the chain transfer agent contained in the (A) copolymer and the (C) metal chelating compound The mass ratio (chelate component/metal component) of the total of the chelating agent (ligand) component and the (D) crosslinking retarder in the (C) metal chelate to the total of the metal component is preferably 100 or more, and more preferably It is preferably 150 or more, more preferably 200 or more, preferably 1000 or less, and more preferably 900 or less.

The pressure-sensitive adhesive composition of the present invention may contain a silane coupling agent, if necessary. The silane coupling agent is not particularly limited, for example, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropyltriethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, Epoxy group-containing silane coupling agents such as 2-(3,4 epoxycyclohexyl)ethyltrimethoxysilane; 3-aminopropyltrimethoxysilane, N-2-(aminoethyl)-3-aminopropylmethyldimethoxysilane, 3- Amino group-containing silane coupling agents such as triethoxysilyl-N-(1,3-dimethylbutylidene)propylamine and N-phenyl-γ-aminopropyltrimethoxysilane; 3-acryloxypropyltrimethoxysilane, 3- (Meth)acryl group-containing silane coupling agents such as methacryloxypropyltriethoxysilane; isocyanate group-containing silane coupling agents such as 3-isocyanatepropyltriethoxysilane; and the like.

The content of the silane coupling agent that can be blended in the pressure-sensitive adhesive composition is preferably 1 part by mass or less, more preferably 0.01 part by mass to 100 parts by mass of the (A) copolymer. 1 mass part, More preferably, it is 0.02 mass part-0.6 mass part. By adjusting the content of the silane coupling agent within the above range, water resistance at the interface when applied to a hydrophilic adherend such as glass of the pressure-sensitive adhesive layer can be mentioned.

The pressure-sensitive adhesive composition of the present invention can be used by blending a crosslinking agent other than the (B) isocyanate-based crosslinking agent, if necessary. Examples of the cross-linking agent (B) other than the isocyanate cross-linking agent include an epoxy cross-linking agent. The epoxy-based crosslinking agent refers to a polyfunctional epoxy compound having two or more epoxy groups in one molecule. Examples of the epoxy crosslinking agent include bisphenol A, epichlorohydrin type epoxy resin, ethylene glycidyl ether, N,N,N′,N′-tetraglycidyl-m-xylenediamine, diglycidylaniline, diamineglycidylamine, 1 ,3-bis(N,N-diglycidylaminomethyl)cyclohexane, 1,6-hexanediol diglycidyl ether, neopentyl glycol diglycidyl ether, ethylene glycol diglycidyl ether, propylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether , Polypropylene glycol diglycidyl ether, sorbitol polyglycidyl ether, glycerol polyglycidyl ether, pentaerythritol polyglycidyl ether, glycerin diglycidyl ether, glycerin triglycidyl ether, polyglycerol polyglycidyl ether, sorbitan polyglycidyl ether, trimethylolpropane polyglycidyl ether , Adipic acid diglycidyl ester, o-phthalic acid diglycidyl ester, triglycidyl-tris(2-hydroxyethyl)isocyanurate, resorcin diglycidyl ether, bisphenol-S-diglycidyl ether and the like.

The content of the epoxy-based cross-linking agent that can be blended in the pressure-sensitive adhesive composition is preferably 0.01 parts by mass to 5 parts by mass with respect to 100 parts by mass of the (A) copolymer, and 0.01 It is more preferably from 4 to 4 parts by mass, further preferably from 0.02 to 3 parts by mass. By adjusting the content of the epoxy-based crosslinking agent within the above range, the cohesive force and heat resistance can be further improved.

If necessary, the pressure-sensitive adhesive composition of the present invention can be used by blending a tackifying resin excluding the (A) copolymer. Examples of the tackifying resin include rosin-based resins such as rosin ester-based resins, terpene-based resins such as terpene-phenolic resins, and petroleum-based resins. Of these, rosin ester resins and terpene phenol resins are preferable.

The rosin ester resin is a rosin resin containing abietic acid as a main component, a disproportionated rosin resin and a hydrogenated rosin resin, a dimer of a resin acid such as abietic acid (polymerized rosin resin), etc. It is a resin obtained by liquefying. The hydroxyl value is adjusted by containing a part of the hydroxyl groups of the alcohol used for the esterification in the resin without being used for the esterification. Examples of the alcohol include polyhydric alcohols such as ethylene glycol, glycerin and pentaerythritol. The resin obtained by esterifying a rosin resin is a rosin ester resin, the resin obtained by esterifying a disproportionated rosin resin is a disproportionated rosin ester resin, and the resin obtained by esterifying a hydrogenated rosin resin is a hydrogenated rosin ester resin or a polymerized rosin. A resin obtained by esterifying a resin is a polymerized rosin ester resin. The terpene phenol resin is a resin obtained by polymerizing a terpene in the presence of phenol.

The content of the tackifying resin that can be added to the pressure-sensitive adhesive composition is preferably 5 parts by mass to 40 parts by mass with respect to 100 parts by mass of the (A) copolymer. By adjusting the content of the tackifying resin in the above range, the constant load releasability of the adhesive film from the adherend can be improved.

In the pressure-sensitive adhesive composition of the present invention, if necessary, dyes, pigments, pigments, optical brighteners, wetting agents, surface tension adjusting agents, thickeners, mildew-proofing agents, preservatives, oxygen absorbers, ultraviolet rays. Used by blending absorbers, near infrared absorbers, water-soluble quenchers, antioxidants, fragrances, metal deactivators, nucleating agents, antistatic agents, alkylating agents, flame retardants, lubricants, processing aids, etc. These can also be used, and these are appropriately selected and blended for use according to the application and purpose of use of the pressure-sensitive adhesive.

(Method for producing pressure-sensitive adhesive composition)
The pressure-sensitive adhesive composition can be produced by mixing the (A) copolymer, (B) isocyanate-based cross-linking agent, (C) metal chelate compound, and other additives used as necessary. .. The pressure-sensitive adhesive composition contains a solvent derived from the production of the (A) copolymer, or is further diluted with a suitable solvent so as to have a viscosity suitable for forming a pressure-sensitive adhesive layer. It may be a solution.

Examples of the solvent include aliphatic hydrocarbons such as hexane and heptane; aromatic hydrocarbons such as toluene and xylene; halogenated hydrocarbons such as methylene chloride and ethylene chloride; acetone, methyl ethyl ketone, 2-pentanone, isophorone, cyclohexanone. And the like; esters such as ethyl acetate and butyl acetate; cellosolve solvents such as ethyl cellosolve; glycol ether solvents such as propylene glycol monomethyl ether; and the like. These solvents may be used alone or in combination of two or more.

The amount of the solvent used may be appropriately adjusted so that the pressure-sensitive adhesive composition has a viscosity suitable for coating and is not particularly limited, but from the viewpoint of coatability, the solid content concentration of the pressure-sensitive adhesive composition is 10%. It is preferably used so as to be in the range of mass% to 95 mass %.

(Use of adhesive composition)
The application of the pressure-sensitive adhesive composition is not particularly limited and can be used in a wide range of applications, but is particularly preferably used for optical applications such as production of optical products and optical members.

The optical product has optical properties (for example, polarization, light refraction, light scattering, light reflection, light transmission, light absorption, light diffraction, optical rotation, visibility, etc.) in the product. The product used. Examples of the optical product include a liquid crystal display device, an organic EL (electroluminescence) display device, a PDP (plasma display panel), a display device such as electronic paper, an input device such as a touch panel, or the display device and the input device. An apparatus in which the above are appropriately combined is included.

The optical member means a member having the optical characteristics. Examples of the optical member include members that configure devices (optical devices) such as the display device (image display device) and the input device, or members used for these devices. Examples of the optical member include a polarizing plate, a wave plate, a retardation plate, an optical compensation film, a brightness enhancement film, a light guide plate, a reflection film, an antireflection film, a transparent conductive film (ITO film), a design film, a decorative film, and a surface. Examples thereof include a protective plate, a prism, a lens, a color filter, a transparent substrate, and a member in which these are laminated (these may be collectively referred to as “optical film”). The "plate" and "film" described above include forms such as plate, film, sheet, etc. For example, "polarizing film" includes "polarizing plate" and "polarizing sheet". As described above, the "optical member" in the present invention includes a member (decorative film, decorative film) that plays a role of decoration and protection while maintaining the visibility and excellent appearance of the display unit in the display device or the input device. And surface protection film).

The material forming the optical member is not particularly limited, and examples thereof include glass, acrylic resin, polycarbonate, polyethylene terephthalate, and metal (including metal oxide).

<2. Adhesive film>
The pressure-sensitive adhesive film of the present invention has a base film and a pressure-sensitive adhesive layer formed of the pressure-sensitive adhesive composition. The pressure-sensitive adhesive layer is formed on at least one side or at least a part of the base film. In addition, in the present invention, the "film" includes a tape and a sheet.

The thickness of the base film is not particularly limited and is appropriately selected, but is usually preferably 10 μm or more, more preferably 20 μm or more, 250 μm or less, and more preferably 200 μm or less.

The base film can be appropriately selected and used according to the application of the adhesive film. For example, when the adhesive film is used for optical applications, it is preferably a transparent base film. The transparent substrate means a substrate that is transparent. As the transparent substrate film, polyester resin such as polyethylene terephthalate (PET); acrylic resin such as polymethylmethacrylate (PMMA); polycarbonate, triacetylserose (TAC), polysulfone, polyarylate, polyimide, polyvinyl chloride , A film made of a plastic material such as polyvinyl acetate, polyethylene, polypropylene, and an ethylene-propylene copolymer. The plastic materials may be used alone or in combination of two or more. Among these, PET is preferable because it is excellent in mechanical strength and dimensional stability. Further, TAC is preferable in that the retardation in the film plane is very small. That is, as the transparent substrate film, a PET film (particularly a biaxially stretched PET film) and a TAC film are preferable.

The total light transmittance (JIS K7361-1 (1997)) of the transparent substrate film in the visible light wavelength region is not particularly limited, but is preferably 85% or more. Since the total light transmittance is 85% or more, the transparency is excellent, and thus the visibility and display quality of the display portion of the optical product and the appearance of the optical product are less likely to be adversely affected.

For the purpose of improving the adhesion to the layer provided on the surface of the base film, one surface or both surfaces thereof may be subjected to a surface treatment by an oxidation method, a textured method or the like, if desired. Examples of the oxidation method include corona discharge treatment, plasma treatment, chromic acid treatment (wet), flame treatment, hot air treatment, ozone/ultraviolet irradiation treatment and the like. Examples of the roughening method include a sandblast method and a solvent treatment method. These surface treatment methods are appropriately selected according to the type of the base film, but in general, the corona discharge treatment method is preferably used from the viewpoints of effects and operability. Further, as the above-mentioned base film, one having a primer treatment on one side or both sides can be used.

The thickness of the pressure-sensitive adhesive layer may be appropriately adjusted depending on the application of the pressure-sensitive adhesive film. For example, in the case of a protective film application (slight adhesion), 0.1 μm to 20 μm is preferable, and in the case of OCA application (strong adhesion), 10 μm to 350 μm is preferable.

The gel fraction of the pressure-sensitive adhesive layer is preferably 30% to 100%, more preferably 40% to 100%, and further preferably 50% to 100%, from the viewpoint of durability and adhesive strength. More preferably, it is particularly preferably 80% to 100%. If the gel fraction is too low, the durability is insufficient due to insufficient cohesive force, and adhesive residue is likely to occur during peeling. The gel fraction can be controlled by the blending amount of the crosslinking agent in the pressure-sensitive adhesive composition, the crosslinking treatment temperature, and the crosslinking treatment time.

The method for forming the pressure-sensitive adhesive layer is not particularly limited, and examples thereof include the following methods (1) and (2).
(1) A method of applying a pressure-sensitive adhesive composition to one or both sides of a substrate film using various coating devices, drying and removing the solvent, and performing curing if necessary.
(2) The pressure-sensitive adhesive composition is applied to the release surface of the release film, which has been subjected to a release treatment, using various coating devices, the solvent is dried and removed, and after curing if necessary, the substrate A method of transferring to one side or both sides of the film.

Examples of the coating device include a reverse roll coater, a gravure coater, a forward roll coater, a knife coater, a wire bar coater, a doctor blade coater, a slot die coater, a curtain coater and a dip coater.

The drying temperature for removing the solvent by drying is preferably 40°C to 200°C, more preferably 60°C to 180°C. The drying time is preferably 5 seconds to 20 minutes, more preferably 10 seconds to 10 minutes. Examples of drying means include hot air, near infrared rays, infrared rays, and high frequencies. The conditions for the curing include, for example, 23° C. for about 3 to 7 days.

The adhesive film may have a release film (separator) on the surface of the adhesive layer until it is used. Without using a separate release film, a release layer is provided on the surface of the base film opposite to the pressure-sensitive adhesive layer-laminated surface, and the release layer is wound in a roll shape so that the exposed surface side of the pressure-sensitive adhesive layer contacts. It may be rotated or laminated in a stacked manner. The release film is used as a protective material for the pressure-sensitive adhesive layer and is peeled off when the pressure-sensitive adhesive film of the present invention is attached to an adherend.

Examples of the release film include paper such as glassine paper, coated paper, laminated paper and various plastic films coated with a release agent such as silicone resin. As the plastic film used for the release film, those mentioned as the base film can be appropriately used. The thickness of the release film is not particularly limited, but is usually 10 μm to 150 μm.

The pressure-sensitive adhesive film of the present invention may be a functional pressure-sensitive adhesive film having a pressure-sensitive adhesive layer on one surface of the base film and a functional layer on the other surface. Examples of the functional layer include coating layers having functions such as scratch resistance, antireflection property, antiglare property (antiglare property), antifouling property, antifingerprint property, chemical resistance, and glass shatterproof property. As a method of forming the functional layer, a known method can be adopted. Further, the functional layer may be a layer in which layers for exerting functions such as antiglare property, antifouling property, antifingerprint property and chemical resistance are laminated. For example, when the hard coat layer has a laminated structure of a layer having excellent scratch resistance and a layer having excellent anti-glare property, the hard coat layer can have excellent properties of both scratch resistance and anti-glare property.

<3. Image display device>
An image display device of the present invention comprises the adhesive film. Examples of the image display device include a liquid crystal display, an organic EL (electroluminescence) display, a plasma display, and electronic paper.

Examples of the adhesive film include an optical film, and specifically, a polarizing plate, a wavelength plate, a retardation plate, an optical compensation film, a brightness enhancement film, a light guide plate, a reflection film, an antireflection film, a transparent conductive film (ITO). Film), a decorative film, a decorative film, a surface protective plate, and the like.

An image display device having the adhesive film of the present invention can be obtained by producing the display device using the optical member having the adhesive film of the present invention or the adhesive film of the present invention.

Hereinafter, the present invention will be described in more detail based on specific examples. The present invention is not limited to the following examples, and can be appropriately modified and implemented within the scope of the invention. Incidentally, the polymerization rate of the copolymer, the weight average molecular weight (Mw), the molecular weight distribution (PDI), the solid content, the viscosity, the adhesive strength of the adhesive composition, the adhesive strength after heating, the adhesive residue, the peeling force to the release film, The gel fraction was evaluated according to the following method.

The abbreviations have the following meanings.
BTEE: ethyl-2-methyl-2-n-butylteranyl-propionate V-70:2,2'-azobis(4-methoxy-2,4-dimethylvaleronitrile)
MA: methyl acrylate BA: butyl acrylate 2-EHA: 2-ethylhexyl acrylate LA: lauryl acrylate CHA: cyclohexyl acrylate 4-HBA: 4-hydroxybutyl acrylate HEA: hydroxyethyl acrylate AcOEt: ethyl acetate

(Polymerization rate)
¹ H-NMR was measured (solvent: CDCl ₃ , internal standard: trimethylsilane (TMS)) using a nuclear magnetic resonance (NMR) measuring device (manufactured by Bruker BioSpin, model: AVANCE500 (frequency 500 MHz)). .. In the obtained NMR spectrum, the integral ratio of the peaks of the vinyl group derived from the monomer and the ester side chain derived from the polymer was determined, and the polymerization rate of the monomer was calculated.

(Weight average molecular weight (Mw) and molecular weight distribution (PDI))
It was determined by gel permeation chromatography (GPC) using a high performance liquid chromatograph (manufactured by Tosoh Corporation, model HLC-8320GPC). Two TSKgel Super Multipore HZ-H (manufactured by Tosoh Corporation) columns were used, a tetrahydrofuran solution was used as a mobile phase, and a differential refractometer was used as a detector. The measurement conditions were a column temperature of 40° C., a sample concentration of 10 mg/mL, a sample injection amount of 10 μm, and a flow rate of 0.2 mL/min. Polystyrene (molecular weight 2,890,000, 1,090,000, 775,000, 427,000, 190,000, 96,400, 37,900, 10,200, 2,630, 440) is used as a standard substance. Then, a calibration curve (calibration curve) was prepared, and the weight average molecular weight (Mw) and the number average molecular weight (Mn) were measured. The molecular weight distribution (PDI=Mw/Mn) was calculated from this measured value.

(Solid content)
A copolymer solution having a mass of W1 (about 1.0 g) was weighed into an aluminum cup (mass W0) and dried under reduced pressure at 130° C. for 1 hour. The mass (W2) of the aluminum cup containing the dried copolymer was measured, and the solid content was calculated from the following formula.
Solid content (mass %)=[(W2-W0)/W1]×100

(viscosity)
A B-type viscometer (trade name: TVB-15, manufactured by Toki Sangyo Co., Ltd.) was used to measure the viscosity at 25° C. and a rotor rotation speed of 60 rpm using a M3 rotor.

<Production of copolymer>
(Synthesis example 1)
In a flask equipped with an argon gas introduction tube and a stirrer, 2-EHA (475.0 g), 4-HBA (25.0 g), V-70 (45.7 mg) and AcOEt (377.2 g) were charged, and argon was charged. After the replacement, BTEE (111.1 mg) was added, and the mixture was reacted at 33° C. for 20 hours to polymerize. The polymerization rate was 88.5%.

After the reaction was completed, AcOEt was added to the reaction solution to obtain a solution of copolymer A. The copolymer A thus obtained had a Mw of 974,000, a PDI of 2.34, and a Tg of -69°C. The content of 4-HBA in the copolymer was 5% by mass, and the content in 100 g of the copolymer was 100%. The amount of reactive functional groups of was 0.03 mol. The copolymer solution had a solid content of 22.3 mass% and a viscosity of 3,881 mPa·s. The content of each structural unit and the amount of reactive functional group in the copolymer were calculated from the charging ratio of the vinyl monomer used in the polymerization reaction.

After the copolymer A solution was dried, it was subjected to ashing, and it was confirmed by inductively coupled plasma mass spectrometry (ICP/MS) that the amount of tellurium compound based on the solid content of the copolymer A solution was 106 ppm in terms of metal. confirmed.

(Synthesis example 2)
BA (475 g), 4-HBA (25 g), V-70 (61.7 mg), AcOEt (377.2 g) were charged into a flask equipped with an argon gas introduction tube and a stirrer, and after substitution with argon, BTEE (200 1.9 mg) was added, and the mixture was reacted at 33° C. for 30 hours to polymerize. The polymerization rate was 86.2%.

After the reaction was completed, AcOEt was added to the reaction solution to obtain a solution of copolymer B. The copolymer B thus obtained had an Mw of 701,000, a PDI of 1.63 and a Tg of -53°C, and the content of 4-HBA in the copolymer was 5% by mass, and the content of the copolymer B in 100 g was 100%. The amount of reactive functional groups of was 0.03 mol. The copolymer solution had a solid content of 19.8 mass% and a viscosity of 2,364 mPa·s. The content of each structural unit and the amount of reactive functional group in the copolymer were calculated from the charging ratio of the vinyl monomer used in the polymerization reaction.

After the copolymer B solution was dried, it was subjected to ashing treatment, and it was confirmed by inductively coupled plasma mass spectrometry (ICP/MS) that the amount of tellurium compound based on the solid content of the copolymer B solution was 197 ppm in terms of metal. confirmed.

(Synthesis example 3)
In a flask equipped with an argon gas introduction tube and a stirrer, BA (300 g), 2-EHA (75 g), CHA (100 g), HEA (25 g), V-70 (38.8 mg), AcOEt (377.2 g). Was charged, BTEE (111.0 mg) was added after purging with argon, and the mixture was reacted at 33° C. for 22 hours to polymerize. The polymerization rate was 81.1%.

After the reaction was completed, AcOEt was added to the reaction solution to obtain a solution of copolymer C. The copolymer C thus obtained had a Mw of 941,000, a PDI of 1.95, and a Tg of -44°C. The content of HEA in the copolymer was 5% by mass, and the reaction in 100 g of the copolymer was carried out. The amount of the functional group was 0.04 mol. The copolymer solution had a solid content of 17.6 mass% and a viscosity of 4368 mPa·s. The content of each structural unit and the amount of reactive functional group in the copolymer were calculated from the charging ratio of the vinyl monomer used in the polymerization reaction.

After the solution of the copolymer C was ashed, it was confirmed by inductively coupled plasma mass spectrometry (ICP/MS) that the amount of the tellurium compound was 128 ppm in terms of metal based on the solid content of the solution of the copolymer C. confirmed.

(Synthesis example 4)
In a flask equipped with an argon gas introduction tube and a stirrer, MA (50 g), 2-EHA (350 g), LA (75 g), 4-HBA (25 g), V-70 (57.1 mg), AcOEt (333. (3 g) was charged, the atmosphere was replaced with argon, BTEE (299.87 mg) was added, and the mixture was reacted at 33° C. for 21 hours to polymerize. The polymerization rate was 89.4%.

After the reaction was completed, AcOEt was added to the reaction solution to obtain a solution of copolymer C. The copolymer D thus obtained had an Mw of 478,000, a PDI of 1.78, and a Tg of -56°C. The content of 4-HBA in the copolymer was 5% by mass, and the content was 100 g of the copolymer. The amount of reactive functional groups of was 0.03 mol. The copolymer solution had a solid content of 42.4 mass% and a viscosity of 7070 mPa·s. The content of each structural unit and the amount of reactive functional group in the copolymer were calculated from the charging ratio of the vinyl monomer used in the polymerization reaction.

After the copolymer D solution was dried, it was subjected to ashing treatment, and it was confirmed by inductively coupled plasma mass spectrometry (ICP/MS) that the amount of tellurium compound relative to the solid content of the copolymer D solution was 285 ppm in terms of metal. confirmed.

<Production of adhesive composition>
(Adhesive composition No. 1)
6.34 parts by mass of an isocyanate compound and 0 part of a zirconium chelate compound with respect to 448.4 parts by mass of the solution of the copolymer A obtained in Synthesis Example 1 (100 parts by mass of the copolymer component, 348.4 parts by mass of AcOEt). 0.08 parts by mass, 13.9 parts by mass of acetylacetone, 196.6 parts by mass of AcOEt, and the mixture was stirred to give a pressure-sensitive adhesive composition No. Got 1.

(Adhesive composition No. 2 to 28)
The pressure-sensitive adhesive composition No. 1 was changed except that the formulation was changed as shown in Tables 2 to 4. In the same manner as in No. 1, adhesive composition No. 2 to 28 were produced. In addition, the solvent amount in Tables 2 to 4 is the total amount of AcOEt contained in the solution of the copolymer and AcOEt added when the pressure-sensitive adhesive composition was prepared.

<Production of adhesive film>
(Adhesive film No. 1)
Adhesive composition No. 1 was applied onto a polyethylene terephthalate (PET) film (thickness 125 μm) so that the thickness after drying would be 7 μm. The PET film coated with the pressure-sensitive adhesive composition was dried at 100° C. for 1 minute to obtain a pressure-sensitive adhesive film No. 1 having a pressure-sensitive adhesive layer. 1 was produced. A release film (25 μm in thickness, manufactured by Toray Film Co., Ltd., “Serapeal (registered trademark) WZ”) was attached to the obtained pressure-sensitive adhesive layer, and allowed to stand at 23° C. for 1 week for curing.

(Adhesive film Nos. 2 to 5)
Adhesive composition No. 1 to the pressure-sensitive adhesive composition No. 1. Adhesive film No. 2 except that it was changed to 2-5. In the same manner as in No. 1, adhesive film No. 2-5 were produced.

(Adhesive film No. 6)
Adhesive composition No. 6 was applied onto a PET film (thickness 125 μm) so that the thickness after drying would be 10 μm. The PET film coated with the pressure-sensitive adhesive composition was dried at 100° C. for 2 minutes to prepare a pressure-sensitive adhesive film having a pressure-sensitive adhesive layer. A release film (25 μm in thickness, manufactured by Toray Film Co., Ltd., “Serapeal (registered trademark) WZ”) was attached to the obtained pressure-sensitive adhesive layer, and allowed to stand at 23° C. for 1 week for curing.

(Adhesive film Nos. 7 to 19)
Adhesive composition No. 6 to the adhesive composition No. 6. No. 7 to 19 adhesive film No. In the same manner as in No. 6, adhesive film No. 7-19 were produced.

(Adhesive film No. 20)
Adhesive composition No. 20 was applied onto a PET film (thickness 50 μm) so that the thickness after drying would be 10 μm. The PET film coated with the pressure-sensitive adhesive composition was dried at 100° C. for 2 minutes to prepare a pressure-sensitive adhesive film having a pressure-sensitive adhesive layer. A release film (25 μm in thickness, manufactured by Higashiyama Film Co., Ltd., “HY-PS11”) was attached to the obtained pressure-sensitive adhesive layer, and allowed to stand at 40° C. for 3 days for curing.

(Adhesive film Nos. 21 to 28)
Adhesive composition No. 20 to the adhesive composition No. 21-28 except that the adhesive film No. 20. Adhesive film No. 21-28 were produced.

<Evaluation of adhesive film>
(IR peak intensity ratio)
Adhesive film No. With respect to the pressure-sensitive adhesive layers 1 to 5, the residual amount of isocyanate groups was evaluated after 3 hours of curing and 7 days (1 week). The residual amount of the isocyanate group was evaluated by measuring the peak intensity at 2275 cm ⁻¹ which is the inverse pair stretching IR peak of the isocyanate group. The measurement was performed by a total reflection method (ATR method) using a Fourier transform infrared spectrophotometer (FT-IR). Table 5 shows the adhesive film No. The intensity ratio to the peak intensity after 5 hours of the curing period of 5 is shown.

(Adhesive force)
The adhesive strength of the adhesive film was measured according to the JIS Z0237 (2009) adhesive strength measuring method (method 1: a test method of peeling a tape and a sheet at 180° from a stainless test plate). Specifically, an adherend whose surface has been cleaned (stainless steel plate (SUS304BA) Ra 50 nm (JIS B 0601 (1994))) is pressure-bonded using a pressure bonding device (roller mass 2 kg), and is adhered to the adherend. The adhesive strength when peeled off at 180° was measured. The test temperature was 23° C. and the peeling speed was 300 mm/min. The adhesive film had a width of 25 mm and a length of 300 mm. After the start of the measurement, the first measurement value of 25 mm in length was ignored, and then the adhesion measurement values of 50 mm in length peeled from the test plate were averaged.

(Adhesive strength after heating)
After the pressure-sensitive adhesive film was pressure-bonded to the adherend in the same manner as in the measurement of the adhesive force, it was heated at 150° C. for 1 hour and then cooled at room temperature (23° C.) for 1 hour. After cooling, the adhesive strength when peeled off at 180° was measured in the same manner as in the measurement of the adhesive strength. Further, the rate of increase in adhesive strength due to heating was calculated by the following formula.
Rate of increase (%)=(adhesive strength after heating/adhesive strength before heating)×100

(Remaining adhesive residue after measuring adhesive strength)
In the measurement of the adhesive strength after the heating, the adherend after peeling off the adhesive film was visually observed to confirm whether or not there was adhesive residue on the adherend. The case where there was no residue was evaluated as "○", and the case where there was residue was evaluated as "x".

(Peeling force)
The peeling force at the time of peeling off the release film is based on the measuring method of the peeling force of JIS Z0237 (2009) (method 4: peeling liner is peeled off at 180° to the adhesive surface of the tape and the sheet). It was measured. Specifically, the pressure-sensitive adhesive film was fixed to a stainless steel plate with a double-sided pressure-sensitive adhesive tape, and the peeling force when the peeling film was peeled at 180° to the pressure-sensitive adhesive film was measured. The test temperature was 23° C. and the peeling speed was 300 mm/min. The width of the release film and the pressure-sensitive adhesive film was 25 mm and the length was 300 mm. After the start of the measurement, the first measured value of the length of 25 mm was ignored, and then the measured values of the peeling force of the length of 50 mm peeled from the adhesive film were averaged.

(Peeling force after heating)
Adhesive film No. Regarding 1 to 5, the pressure-sensitive adhesive film to which the release film was attached was heated at 100° C. for 1 hour and then cooled at 23° C. for 1 hour. Adhesive film No. Regarding 6 to 28, the pressure-sensitive adhesive film to which the release film was attached was heated at 150°C for 1 hour and then cooled at 23°C for 1 hour. After cooling, the peeling force when peeled at 180° was measured in the same manner as the measurement of the peeling force. Further, the increase rate of the peeling force due to heating was calculated by the following formula.
Rate of increase (%)=(peeling force after heating/peeling force before heating)×100

(Gel fraction)
The pressure-sensitive adhesive composition was applied to a release film and dried at 100° C. for 1 minute (pressure-sensitive adhesive composition Nos. 1 to 5) or 100° C. for 2 minutes (pressure-sensitive adhesive composition Nos. 6 to 28). Then, after leaving still at 23 degreeC for 1 week and curing, the adhesive layer formed on the peeling film was peeled off.
The pressure-sensitive adhesive layer having a mass of W1 (about 0.10 g) was weighed out on a stainless steel wire mesh (400 mesh) having a mass of W0, and immersed in ethyl acetate at 60° C. for 24 hours. Then, the pressure-sensitive adhesive layer and the stainless steel wire mesh were taken out from ethyl acetate, dried at 23° C. for 24 hours, and further dried under reduced pressure at 130° C. for 1 hour. After drying, the weight W2 of the stainless wire gauze containing the dried adhesive layer was measured, and the gel fraction was calculated from the following formula.
Gel fraction (mass %)=[(W2-W0)/W1]×100

イソシアネート化合物：旭化成社製、デュラネート（登録商標）ＴＰＡ−１００
ジルコニウムキレート化合物：マツモトファインケミカル社製、オルガチックス（登録商標）ＺＣ−１５０（ジルコニウムテトラアセチルアセトネート）
チタンキレート化合物：マツモトファインケミカル社製、オルガチックス（登録商標）ＴＣ−７５０（チタンジイソプロポキシビス（エチルアセトアセテート））
アルミニウムキレート化合物：川研ファインケミカル社製、アルミキレートＡ（アルミニウムトリス（アセチルアセトネート））
有機スズ化合物：日東化成社製、ネオスタン（登録商標）Ｕ８１０（ジオクチルスズ）
アミン化合物：東京化成社製、１，４−ジアザビシクロ［２．２．２］オクタン

Isocyanate compound: Duranate (registered trademark) TPA-100 manufactured by Asahi Kasei Corporation
Zirconium chelate compound: Organix (registered trademark) ZC-150 (zirconium tetraacetylacetonate) manufactured by Matsumoto Fine Chemical Co., Ltd.
Titanium chelate compound: Organix (registered trademark) TC-750 (titanium diisopropoxybis(ethylacetoacetate)) manufactured by Matsumoto Fine Chemical Co., Ltd.
Aluminum chelate compound: Aluminum chelate A (Aluminum tris(acetylacetonate)) manufactured by Kawaken Fine Chemicals Co., Ltd.
Organotin compound: Nitto Kasei Co., Ltd., Neostan (registered trademark) U810 (dioctyltin)
Amine compound: 1,4-diazabicyclo[2.2.2]octane manufactured by Tokyo Chemical Industry Co., Ltd.

As shown in Table 5, when a zirconium chelate compound or a titanium chelate compound was used as a crosslinking accelerator (adhesive composition Nos. 1 and 2), the IR peak intensity ratio was small even after a curing period of 3 hours. Therefore, it is understood that these chelate compounds have the cross-linking promoting performance, similarly to the organotin compound (pressure-sensitive adhesive composition No. 3). When an amine compound was used as a crosslinking accelerator (pressure-sensitive adhesive composition No. 4), the IR peak intensity ratio was 1.0 after a curing period of 3 hours. In other words, it can be seen that the amine compound does not have a crosslinking promotion performance.

Further, as shown in Table 5, when the organotin compound was used as the crosslinking accelerator (adhesive film No. 3), the peeling force was higher than that when no crosslinking accelerator was used (adhesive film No. 5). The rate of increase due to heating is high. On the other hand, when a zirconium chelate compound or a titanium chelate compound is used as the crosslinking accelerator (adhesive films No. 1 and 2), the increase rate of the peeling force due to heating is low, and the heavy peeling is suppressed. There is.

Further, as shown in Tables 6 to 8, when a metal chelate compound (zirconium chelate compound, titanium chelate compound, aluminum chelate compound) is used as a crosslinking accelerator (adhesive films Nos. 6 to 13, 16, 17), The increase rate of the adhesive force to the adherend due to heating is also lower than that in the case where the crosslinking accelerator is not used (Adhesive films No. 15 and 19). Furthermore, when the crosslinking accelerator is not used for the copolymer A (adhesive film No. 15), the adhesive strength after heating is significantly increased and the adherend is contaminated. On the other hand, the adhesive film No. In Nos. 6 to 14, the increase in adhesive strength due to heating was suppressed and the adherend was not contaminated. The adhesive film No. No. 19 shows no stain on the adherend, although the adhesive strength after heating is significantly increased. It is considered that this is because the copolymer B has a higher cohesive force than the copolymer A. In addition, the adhesive film No. It is considered that Nos. 22, 25, and 28 are due to the curing conditions at the time of producing the pressure-sensitive adhesive film and the difference in the thickness of the base film.

The present invention includes the following embodiments.
(Embodiment 1)
(A) a (meth) acrylic copolymer containing a (meth) acrylic copolymer having a reactive functional group, (B) an isocyanate crosslinking agent, and (C) a metal chelate compound. A pressure-sensitive adhesive composition, wherein the coalesced product is obtained by living radical polymerization, has a weight average molecular weight of 200,000 to 2,000,000, and has a molecular weight distribution (PDI) of less than 3.0.

(Embodiment 2)
The content of the (C) metal chelate compound is 2 parts by mass or more based on 1 part by mass of the metal compound derived from the chain transfer agent contained in the (A) (meth)acrylic copolymer. The pressure-sensitive adhesive composition according to certain embodiment 1.

(Embodiment 3)
The reactive functional group contained in the (A) (meth)acrylic copolymer is selected from the group consisting of a hydroxy group, a carboxy group, a sulfonic acid group, a phosphoric acid group, a phosphonic acid group, a phosphine group and an epoxy group. The pressure-sensitive adhesive composition according to embodiment 1 or 2, which is at least one kind.

(Embodiment 4)
The (A) (meth)acrylic copolymer contains a structural unit derived from a vinyl monomer having a reactive functional group in an amount of 0.1% by mass to 20% by mass in 100% by mass of the whole copolymer. The pressure-sensitive adhesive composition according to any one of Embodiments 1 to 3.

(Embodiment 5)
Any of Embodiments 1 to 4 wherein the (A) (meth)acrylic copolymer contains a structural unit derived from a (meth)acrylic monomer in an amount of 80% by mass or more based on 100% by mass of the entire copolymer. The pressure-sensitive adhesive composition according to item 1.

(Embodiment 6)
The content of the (B) isocyanate-based crosslinking agent is 0.01 to 20 parts by mass with respect to 100 parts by mass of the (meth)acrylic copolymer, according to any one of Embodiments 1 to 5. The adhesive composition described.

(Embodiment 7)
The (C) metal chelate compound is at least one metal selected from the group consisting of aluminum, zirconium, titanium, zinc, barium, calcium, copper, strontium, chromium, cobalt, iron, indium, magnesium, manganese and nickel. The pressure-sensitive adhesive composition according to any one of Embodiments 1 to 6, which contains atoms.

(Embodiment 8)
The pressure-sensitive adhesive composition according to any one of Embodiments 1 to 7, wherein the (C) metal chelate compound contains a ligand represented by the following formula (3).

［式中、Ｒ¹¹およびＲ¹²は、それぞれ独立に、水素、アルキル基またはアルコキシ基を示す。］

[In the formula, R ¹¹ and R ¹² each independently represent hydrogen, an alkyl group, or an alkoxy group. ]

(Embodiment 9)
The content of the (C) metal chelate compound is 0.01 parts by mass to 0.5 parts by mass with respect to 100 parts by mass of the (meth)acrylic copolymer, and any one of the embodiments 1-8. The pressure-sensitive adhesive composition according to.

(Embodiment 10)
The pressure-sensitive adhesive composition according to any one of Embodiments 1 to 9, wherein the pressure-sensitive adhesive composition further contains (D) a crosslinking retarder.

(Embodiment 11)
The pressure-sensitive adhesive composition according to any one of Embodiments 1 to 10, which is for optics.

(Embodiment 12)
An adhesive film comprising a substrate film and an adhesive layer formed from the adhesive composition according to any one of Embodiments 1 to 11.

(Embodiment 13)
An image display device comprising the adhesive film according to embodiment 12.

Claims (13)

(A) contains a (meth)acrylic copolymer having a reactive functional group, (B) an isocyanate crosslinking agent, and (C) a metal chelate compound,
The (A) (meth)acrylic copolymer is obtained by living radical polymerization, has a weight average molecular weight of 200,000 to 2,000,000, and has a molecular weight distribution (PDI) of less than 3.0. A pressure-sensitive adhesive composition comprising: The content of the (C) metal chelate compound is 2 parts by mass or more based on 1 part by mass of the metal compound derived from the chain transfer agent contained in the (A) (meth)acrylic copolymer. The pressure-sensitive adhesive composition according to claim 1. The reactive functional group contained in the (A) (meth)acrylic copolymer is selected from the group consisting of a hydroxy group, a carboxy group, a sulfonic acid group, a phosphoric acid group, a phosphonic acid group, a phosphine group and an epoxy group. The pressure-sensitive adhesive composition according to claim 1, which is at least one kind. The (A) (meth)acrylic copolymer contains a structural unit derived from a vinyl monomer having a reactive functional group in an amount of 0.1% by mass to 20% by mass in 100% by mass of the whole copolymer. The pressure-sensitive adhesive composition according to claim 1. The (A) (meth)acrylic copolymer contains a structural unit derived from a (meth)acrylic monomer in an amount of 80% by mass or more based on 100% by mass of the entire copolymer. The pressure-sensitive adhesive composition according to item 1. Content of the said (B) isocyanate type crosslinking agent is 0.01 mass part-20 mass parts with respect to 100 mass parts of (meth)acrylic-type copolymers. The pressure-sensitive adhesive composition described. The (C) metal chelate compound is at least one metal selected from the group consisting of aluminum, zirconium, titanium, zinc, barium, calcium, copper, strontium, chromium, cobalt, iron, indium, magnesium, manganese and nickel. The pressure-sensitive adhesive composition according to any one of claims 1 to 6, which contains atoms. The pressure-sensitive adhesive composition according to any one of claims 1 to 7, wherein the (C) metal chelate compound contains a ligand represented by the following formula (3).

[In the formula, R ¹¹ and R ¹² each independently represent hydrogen, an alkyl group, or an alkoxy group. ] Content of the said (C) metal chelate compound is 0.01 mass part-0.5 mass part with respect to 100 mass parts of (meth)acrylic-type copolymers. The pressure-sensitive adhesive composition according to. The pressure-sensitive adhesive composition according to any one of claims 1 to 9, wherein the pressure-sensitive adhesive composition further contains (D) a crosslinking retarder. The pressure-sensitive adhesive composition according to any one of claims 1 to 10, which is for optics. An adhesive film comprising a base film and an adhesive layer formed from the adhesive composition according to any one of claims 1 to 11. An image display device comprising the adhesive film according to claim 12.