TWI814998B - Adhesive composition, adhesive layer and adhesive sheet - Google Patents

Abstract

The invention relates to an adhesive composition containing a base polymer, a leuco pigment and a photoacid generator.

Description

Adhesive composition, adhesive layer and adhesive sheet

The present invention relates to an adhesive composition, an adhesive layer containing the adhesive composition, and an adhesive sheet provided with the adhesive layer.

Previously, for adhesive tapes, it was better to use transparent tapes because they were easier to control during processing steps or lamination operations. On the other hand, colored adhesive tapes are also used for the purpose of changing the design or improving the style and visibility.

For example, Patent Document 1 describes a colored adhesive sheet that aims to make the adhesive sheet thinner and has the ability to hide defects of the adherend by taking advantage of the style, decoration, or concealment properties of the adherend. Prior technical literature patent documents

Patent Document 1: Japanese Patent Application Publication No. 2013-245298

[Problem to be solved by the invention]

The adhesive sheet described in the above-mentioned Patent Document 1 is colored by containing a dye in its adhesive layer. Therefore, the formed adhesive sheet is in a colored state, and the adhesive sheet cannot be colored at any point such as after the sheet lamination step.

Therefore, one object of the present invention is to provide an adhesive composition that can change color or be colored at any time, and an adhesive layer and adhesive sheet using the adhesive composition. [Technical means to solve problems]

The inventors of the present invention have conducted intensive research with the aim of providing an adhesive composition that can change color or be colored at any time. As a result, it is assumed that a leuco pigment that is colored by reacting with an acid and a photoacid generator that generates acid by irradiation of active energy rays are used in an adhesive composition in combination. That is, they discovered that by irradiating an adhesive composition containing a leuco pigment and a photoacid generator with active energy rays, the color can be changed or colored at any time, and the present invention was completed.

One embodiment of the present invention relates to an adhesive composition, which contains a base polymer, a leuco pigment, and a photoacid generator.

In one embodiment of the present invention, a leuco pigment whose absorption wavelength changes depending on the pH value is preferred.

In one embodiment of the present invention, the adhesive composition preferably contains 0.1 to 30 parts by mass of leuco pigment per 100 parts by mass of the base polymer.

In one embodiment of the present invention, it is preferable that the leuco pigment is at least one pigment selected from the group consisting of phthalide dyes and fluorescent yellow parent dyes.

In one embodiment of the present invention, the adhesive composition preferably contains 0.1 to 30 parts by mass of the photoacid generator per 100 parts by mass of the base polymer.

In one embodiment of the present invention, it is preferable that the photoacid generator is at least one compound selected from the group consisting of strontium salt-based compounds, iodonium salt-based compounds, and aromatic N-oxycarboxylimine sulfonate. .

In one embodiment of the present invention, it is preferable that the base polymer contains an acrylic polymer.

In one embodiment of the present invention, the adhesive composition may change color by irradiation with active energy rays.

In one embodiment of the present invention, the adhesive composition may be colored by irradiation with active energy rays.

One embodiment of the present invention relates to an adhesive layer, which includes the above-mentioned adhesive composition.

One embodiment of the present invention relates to an adhesive sheet provided with the above-mentioned adhesive layer.

In one embodiment of the present invention, the adhesive sheet may be provided with a UV (ultraviolet, ultraviolet) absorbing layer on one side of the adhesive layer.

In one embodiment of the present invention, the UV absorbing layer may be an adhesive layer containing a UV absorbing agent.

In one embodiment of the present invention, the adhesive layer in the adhesive sheet can be formed on the base material. [Effects of the invention]

The adhesive composition according to one embodiment of the present invention can change or be colored by irradiating active energy rays. Therefore, the adhesive layer or adhesive sheet using the above-mentioned adhesive composition may change or be colored at any time after lamination.

Hereinafter, embodiments of the present invention will be described in detail. In addition, the present invention is not limited to the embodiments described below.

＜Adhesive composition＞ An adhesive composition according to one embodiment of the present invention is characterized by containing a base polymer, a leuco pigment, and a photoacid generator.

According to the adhesive layer or adhesive sheet obtained by using the above-mentioned adhesive composition, by irradiating active energy rays, an acid is generated from the photoacid generator, and the acid reacts with the leuco pigment, thereby making the adhesive layer or adhesive sheet Discoloration or staining of the sheet. That is, the adhesive layer or adhesive sheet obtained by using the above-mentioned adhesive composition can be discolored or colored by irradiation with active energy rays, and therefore can be discolored or colored at any point after lamination.

In this specification, "A to B" indicating a range means "A or more and B or less". In addition, in this specification, "weight" and "mass", "weight%" and "mass%", and "weight part" and "mass part" are used as synonyms respectively.

In this specification, the so-called "discoloration" refers to the color change before and after irradiation of active energy rays. The concept includes: the disappearance of color by irradiation of active energy rays, the appearance of color by irradiation of active energy rays, and the appearance of color by irradiation of active energy rays. The original color changes to different colors due to the irradiation of active energy rays. In addition, in this specification, the so-called "coloring" refers to the appearance of color before and after irradiation of active energy rays. The concept includes: the appearance of color by irradiation of active energy rays, and the change of original color by irradiation of active energy rays. The color changes into different colors, but the concept does not include the disappearance of the color through the irradiation of active energy rays.

Each component contained in the above-mentioned adhesive composition will be described in detail below.

(base polymer) In the adhesive composition according to one embodiment of the present invention, the base polymer constituting the adhesive composition is not particularly limited, and known polymers used in adhesives can be used. Examples include: acrylic polymers, rubber polymers, vinyl alkyl ether polymers, polysiloxane polymers, polyester polymers, polyamide polymers, and urethane polymers. materials, fluorine-based polymers, epoxy-based polymers, etc. Among them, in terms of adhesiveness, acrylic polymers and rubber-based polymers are preferred. Furthermore, from the viewpoint of significant change in appearance when discoloration or coloring occurs, an acrylic polymer with higher transparency is more preferred. In addition, only one type of this polymer may be used alone, or two or more types may be used in combination.

Hereinafter, an embodiment in which the adhesive composition according to one embodiment of the present invention contains an acrylic polymer as a base polymer will be mainly described. However, the present invention is not limited to this embodiment.

The adhesive composition according to one embodiment of the present invention may contain an acrylic polymer as a base polymer. Typically, the above-mentioned adhesive composition may be an acrylic adhesive composition containing an acrylic polymer as a main component. The acrylic adhesive composition has excellent transparency.

The adhesive composition according to one embodiment of the present invention preferably contains, for example, a linear or branched alkyl group having a carbon number of 1 to 20 at the end of the ester at a ratio of 40% by weight or more. The acrylic polymer which is the monomer component of alkyl (meth)acrylate serves as the base polymer.

Hereinafter, a (meth)acrylic acid alkyl ester having an alkyl group with a carbon number of X or more and Y or less at the ester end may be described as "(meth)acrylic acid C _XY alkyl ester". From the perspective of easily obtaining a balance of properties, it is more suitable when the ratio of C _1-20 alkyl (meth)acrylate in the total monomer component of an acrylic polymer exceeds 50% by weight, for example It may be 55% by weight or more, 60% by weight or more, or 70% by weight or more.

Considering the same reason, the ratio of C _1-20 alkyl (meth)acrylate in the monomer component may be, for example, 99.9% by weight or less, 99.5% by weight or less, or 99% by weight or less. In another aspect of the acrylic polymer, the proportion of C _1-20 (meth)acrylic acid alkyl ester in the total monomer component can be, for example, 98% by weight or less, from the viewpoint of improving the cohesiveness of the adhesive layer. Specifically, it may be 95% by weight or less, 85% by weight or less (for example, less than 80% by weight), 70% by weight or less, or 60% by weight or less.

Non-limiting specific examples of C _1-20 alkyl (meth)acrylate include: (meth)acrylic acid methyl ester, (methyl)acrylic acid ethyl ester, (methyl)acrylic acid propyl ester, (meth)acrylic acid propyl ester, (meth)acrylic acid ethyl ester Ester) isopropyl acrylate, (methyl) n-butyl acrylate, (methyl) isobutyl acrylate, (methyl) second butyl acrylate, (methyl) third butyl acrylate, (methyl) acrylic acid Amyl ester, (methyl) isopentyl acrylate, (methyl) hexyl acrylate, (methyl) heptyl acrylate, (methyl) octyl acrylate, (methyl) 2-ethylhexyl acrylate, (methyl) Ester) Isooctyl acrylate, (Methyl) nonyl acrylate, (Methyl) isononyl acrylate, (Methyl) decyl acrylate, (Methyl) isodecyl acrylate, (meth) Undecyl acrylate Ester, dodecyl (meth)acrylate, tridecyl (meth)acrylate, myristyl (meth)acrylate, pentadecyl (meth)acrylate, (meth) Cetyl acrylate, heptadecyl (meth)acrylate, stearyl (meth)acrylate, isostearyl (meth)acrylate, nonadecyl (meth)acrylate, (meth)acrylate base) Eicosanyl acrylate, etc.

Among these, it is preferable to use at least C _4-20 alkyl (meth)acrylate, and more preferably at least C _4-18 alkyl (meth)acrylate is used. For example, it is preferable to include one or both of n-butyl acrylate (BA) and 2-ethylhexyl acrylate (2EHA) as the above-mentioned monomer components, and an acrylic adhesive containing at least 2EHA is particularly preferable. Other examples of C _4-20 alkyl (meth)acrylate that can be preferably used include isononyl acrylate, n-butyl methacrylate (BMA), 2-ethylhexyl methacrylate ( 2EHMA), isostearyl acrylate (iSTA), etc.

In some aspects, the monomer component constituting the acrylic polymer may contain C _4-18 alkyl (meth)acrylate at a ratio of 40% by weight or more. The proportion of C _4-18 alkyl (meth)acrylate in the monomer component may be, for example, 50% by weight or more, 60% by weight or more, or 65% by weight or more. It may also be a monomer component containing C _6-18 alkyl (meth)acrylate in a ratio above any of the lower limits mentioned above.

In addition, from the viewpoint of improving the cohesiveness of the adhesive layer, the proportion of C _4-18 alkyl (meth)acrylate in the monomer component is usually 99.5% by weight or less, and may be 95% by weight. It may be 85% by weight or less, or 75% by weight or less. It may also be a monomer component containing C _6-18 alkyl (meth)acrylate in a ratio below any of the above upper limits.

The monomer components constituting the acrylic polymer may contain other monomers (copolymerizable monomers) copolymerizable with the alkyl (meth)acrylate together with the alkyl (meth)acrylate, if necessary. As the copolymerizable monomer, monomers having polar groups (such as carboxyl groups, hydroxyl groups, nitrogen atom-containing rings, etc.) or monomers having a homopolymer with a relatively high glass transition temperature (such as 10° C. or higher) can be preferably used. Monomers with polar groups can help introduce cross-linking points into acrylic polymers or improve the cohesion of adhesives. A copolymerizable monomer can be used individually by 1 type or in combination of 2 or more types.

Non-limiting specific examples of the copolymerizable monomer include the following.

Monomers containing carboxyl groups: such as acrylic acid, methacrylic acid, carboxyethyl acrylate, carboxypentyl acrylate, itaconic acid, maleic acid, fumaric acid, crotonic acid, methacrylic acid, etc.

Monomers containing acid anhydride groups: such as maleic anhydride and itaconic anhydride.

Hydroxyl-containing monomers: such as 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate , 4-hydroxybutyl (meth)acrylate, 6-hydroxyhexyl (meth)acrylate, 8-hydroxyoctyl (meth)acrylate, 10-hydroxydecyl (meth)acrylate, (meth)acrylic acid (meth)acrylic acid hydroxyalkyl esters such as 12-hydroxylauryl ester and (meth)acrylic acid (4-hydroxymethylcyclohexyl)methyl ester.

Monomers containing sulfonic acid or phosphate groups: such as styrenesulfonic acid, allylsulfonic acid, sodium vinylsulfonate, 2-(meth)acrylamide-2-methylpropanesulfonic acid, (methyl ) Acrylamide propanesulfonic acid, (meth)acrylic acid sulfopropyl ester, (meth)acryloxynaphthalene sulfonic acid, 2-hydroxyethylacrylyl phosphate, etc.

Epoxy group-containing monomers: such as glycidyl (meth)acrylate or (meth)acrylic acid-2-ethyl glycidyl ether and other epoxy group-containing acrylates, allyl glycidyl ether, (methyl ) Glycidyl acrylate, etc.

Monomers containing cyano groups: such as acrylonitrile, methacrylonitrile, etc.

Monomers containing isocyanate groups: for example, 2-isocyanatoethyl (meth)acrylate, etc.

Monomers containing amide groups: such as (meth)acrylamide; N,N-dimethyl(meth)acrylamide, N,N-diethyl(meth)acrylamide, N,N -Dipropyl(meth)acrylamide, N,N-diisopropyl(meth)acrylamide, N,N-di(n-butyl)(meth)acrylamide, N,N- Di(tert-butyl)(meth)acrylamide and other N,N-dialkyl(meth)acrylamide; N-ethyl(meth)acrylamide, N-isopropyl(methyl) ) Acrylamide, N-butyl(meth)acrylamide, N-n-butyl(meth)acrylamide, etc. N-alkyl(meth)acrylamide; N-vinyl acetamide, etc. N-vinyl carboxamides; monomers with hydroxyl and amide groups, such as N-(2-hydroxyethyl)(meth)acrylamide, N-(2-hydroxypropyl)(methyl) Acrylamide, N-(1-hydroxypropyl)(meth)acrylamide, N-(3-hydroxypropyl)(meth)acrylamide, N-(2-hydroxybutyl)(methyl ) acrylamide, N-(3-hydroxybutyl)(meth)acrylamide, N-(4-hydroxybutyl)(meth)acrylamide and other N-hydroxyalkyl(meth)acrylamide Amines; monomers with alkoxy and amide groups, such as N-methoxymethyl(meth)acrylamide, N-methoxyethyl(meth)acrylamide, N-butoxy Methyl (meth) acrylamide and other N-alkoxyalkyl (meth) acrylamide; others, N, N-dimethylaminopropyl (meth) acrylamide, N-(methyl ) Acrylyl 𠰌line, etc.

Monomers containing amine groups: for example, aminoethyl (meth)acrylate, N,N-dimethylaminoethyl (meth)acrylate, and tert-butylaminoethyl (meth)acrylate.

Monomers with epoxy groups: for example, glycidyl (meth)acrylate, methyl glycidyl (meth)acrylate, and allyl glycidyl ether.

Monomers with rings containing nitrogen atoms: such as N-vinyl-2-pyrrolidone, N-methylvinylpyrrolidone, N-vinylpyridine, N-vinylpiperidone, N-vinyl Pyrimidine, N-vinyl piperazole, N-vinylpyrrolidone, N-vinylpyrrole, N-vinylimidazole, N-vinylethazole, N-(meth)acrylyl-2-pyrrolidinone , N-(meth)acrylylpiperidine, N-(meth)acrylylpyrrolidine, N-vinyl𠰌line, N-vinyl-3-𠰌linone, N-vinyl-2- Caprolactam, N-vinyl-1,3-㗁𠯤-2-one, N-vinyl-3,5-𠰌lindione, N-vinylpyrazole, N-vinyliso㗁azole, N-vinylthiazole, N-vinylisothiazole, N-vinylpyridine, etc. (for example, N-vinyl-2-caprolactam and other lactams).

Monomers with succinimide skeleton: such as N-(meth)acryloxymethylene succinimide, N-(meth)acryloxy-6-oxyhexamethylenebutane Diamine, N-(meth)acryl-8-oxyhexamethylenesuccinimine, etc.

Maleimines: such as N-cyclohexylmaleimide, N-isopropylmaleimide, N-laurylmaleimide, N-benzene Maleic imide, etc.

Iconidimines: such as N-methyl itonimide, N-ethyl itonimide, N-butyl itonimide, N-octyl itonimide, N- 2-Ethylhexyl Ikonimide, N-cyclohexyl Ikonimide, N-lauryl Ikonimide, etc.

(Meth)acrylic acid aminoalkyl esters: such as (meth)acrylic acid aminoethyl ester, (meth)acrylic acid N,N-dimethylaminoethyl ester, (meth)acrylic acid N,N-diethyl acrylate Aminoethyl ester, tert-butylaminoethyl (meth)acrylate.

Monomers containing alkoxy groups: such as 2-methoxyethyl (meth)acrylate, 3-methoxypropyl (meth)acrylate, 2-ethoxyethyl (meth)acrylate, (meth)acrylate alkoxyl alkyl (metha)acrylate, such as propoxyethyl acrylate, butoxyethyl (meth)acrylate, ethoxypropyl (meth)acrylate, etc. Class; (meth)acrylic acid alkoxy alkylene glycol (meth)acrylic acid methoxyethylene glycol ester, (meth)acrylic acid polyethylene glycol ester, (meth)acrylic acid polypropylene glycol ester, etc. glycol esters (such as alkoxy polyalkylene glycol (meth)acrylate).

Monomers containing alkoxysilyl groups: such as 3-(meth)acryloxypropyltrimethoxysilane, 3-(meth)acryloxypropyltriethoxysilane, 3-(meth)acryloxypropyltriethoxysilane (Meth)acrylates containing alkoxysilyl groups such as acryloyloxypropylmethyldimethoxysilane, 3-(meth)acryloxypropylmethyldiethoxysilane or Vinyl compounds containing alkoxysilyl groups such as vinyltrimethoxysilane, vinyltriethoxysilane, etc.

Vinyl esters: such as vinyl acetate, vinyl propionate, etc.

Vinyl ethers: vinyl alkyl ethers such as methyl vinyl ether or ethyl vinyl ether.

Aromatic vinyl compounds: such as styrene, α-methylstyrene, vinyltoluene, etc.

Olefins: such as ethylene, butadiene, isoprene, isobutylene, etc.

(Meth)acrylates with alicyclic hydrocarbon groups: such as (meth)cyclopentyl acrylate, (meth)cyclohexyl acrylate, (meth)acrylic acid isoester, dicyclopentyl methacrylate, (meth)acrylate adamantyl acrylate and other alicyclic hydrocarbon group-containing (meth)acrylates.

(Meth)acrylates with aromatic hydrocarbon groups: such as phenyl (meth)acrylate, phenoxyethyl (meth)acrylate, benzyl (meth)acrylate, etc. (meth)acrylic acid containing aromatic hydrocarbon groups ester.

Others, (meth)acrylates containing heterocycles such as tetrahydrofuran methyl (meth)acrylate, (meth)acrylates containing vinyl chloride or fluorine atoms, and (meth)acrylates containing halogen atoms, polysiloxane Silicon atom-containing (meth)acrylate such as (meth)acrylate, (meth)acrylate obtained from terpene derivative alcohol, etc.

When such a copolymerizable monomer is used, the usage amount is not particularly limited, but is usually preferably 0.01% by weight or more of the total monomer components. From the viewpoint of better exerting the use effect of the copolymerizable monomer, the usage amount of the copolymerizable monomer may be 0.1% by weight or more of the total monomer component, or may be 0.5% by weight or more. In addition, from the viewpoint of easily obtaining a balance of adhesive properties, the usage amount of the copolymerizable monomer is usually 50% by weight or less of the total monomer components, preferably 40% by weight or less.

In several aspects, the monomer components constituting the acrylic polymer may contain monomers having nitrogen atoms. This can improve the cohesive force of the adhesive and preferably improve the peeling force over time. A preferred example of the monomer having a nitrogen atom includes a monomer having a ring containing a nitrogen atom. As the monomer having a ring containing a nitrogen atom, those exemplified above can be used, and examples thereof include N-vinyl cyclic amide represented by the following general formula (1).

[Chemical 1]

Here, in the general formula (1), R ¹ is a divalent organic group, specifically -(CH ₂ ) _n -. n is an integer from 2 to 7 (preferably 2, 3 or 4). Among them, N-vinyl-2-pyrrolidone can be preferably used. Other preferred examples of the monomer having a nitrogen atom include (meth)acrylamide.

The usage amount of the monomer having a nitrogen atom (preferably a monomer having a ring containing a nitrogen atom) is not particularly limited. For example, it can be 1 wt% or more, 3 wt% or more, or 5 wt% or more of the total monomer component. Or more than 7% by weight. In one aspect, the amount of the monomer having nitrogen atoms may be 10% by weight or more, 15% by weight or more, or 20% by weight or more of the total monomer component. Furthermore, the usage amount of the monomer having a nitrogen atom is preferably 40% by weight or less, 35% by weight or less, 30% by weight or less, or 25% by weight or less of the total monomer component. In another aspect, the usage amount of the monomer having nitrogen atoms may be, for example, 20% by weight or less or less than 15% by weight of the total monomer component.

In several aspects, the monomer components constituting the acrylic polymer may contain hydroxyl-containing monomers. Through the use of hydroxyl-containing monomers, the cohesive force of the adhesive or the degree of cross-linking (for example, cross-linking by an isocyanate cross-linking agent) can be better adjusted. When using a hydroxyl-containing monomer, the usage amount is not particularly limited. For example, it may be 0.01% by weight or more, 0.1% by weight or more, 0.5% by weight or more, or 1% of the total monomer component. More than 5% by weight or more than 10% by weight. Furthermore, from the viewpoint of suppressing the water absorption of the adhesive layer, in some aspects, the usage amount of the hydroxyl-containing monomer is preferably 40% by weight or less of the total monomer component, or 30% by weight or less. , may be 25% by weight or less, or may be 20% by weight or less. In another aspect, the usage amount of the hydroxyl-containing monomer may be, for example, 15% by weight or less, 10% by weight or less, or 5% by weight or less of the total monomer component.

In the adhesive composition according to one embodiment of the present invention, the monomer component of the acrylic polymer may contain the above-exemplified alkoxyalkyl (meth)acrylate or alkoxypolyalkylene glycol (meth)acrylate. base) acrylate, or it does not need to be contained. In one aspect of the technology of this embodiment, the proportion of the alkoxyalkyl (meth)acrylate in the monomer component of the acrylic polymer is less than 20% by weight, and the alkoxypolyalkylene bis The ratio of alcohol (meth)acrylate is less than 20% by weight. Thereby, the adhesive layer can be easily formed into a sheet without problems such as gelation. By adopting the above monomer composition, the solid content concentration of the monomer mixture can be maintained within a specific range, and the polymer can be preferably polymerized into a desired high molecular weight body (for example, the weight average molecular weight (Mw) exceeds 30×10 ⁴ , typically Suppose Mw is 40×10 ⁴ or more).

The proportion of alkoxyalkyl (meth)acrylate in the above monomer components is preferably less than 10% by weight, more preferably less than 3% by weight, and further preferably less than 1% by weight. In a particularly preferred aspect, the above monomer component does not substantially contain alkoxyalkyl (meth)acrylate (content 0 to 0.3% by weight). Similarly, the proportion of alkoxy polyalkylene glycol (meth)acrylate in the above monomer components is preferably less than 10% by weight, more preferably less than 3% by weight, and even more preferably Less than 1% by weight, in a particularly preferred aspect, the above-mentioned monomer component does not substantially contain alkoxy polyalkylene glycol (meth)acrylate (content 0-0.3% by weight).

Furthermore, regarding the monomer components of a preferred aspect of the acrylic polymer, from the viewpoint of inhibiting gelation, alkoxyalkyl (meth)acrylate and alkoxypolyalkylene glycol ( The total ratio of methacrylate is limited to less than 20% by weight. The total ratio of the above-mentioned alkoxyalkyl (meth)acrylate and alkoxypolyalkylene glycol (meth)acrylate is more preferably less than 10% by weight, further preferably less than 3% by weight, Particularly preferably, it is less than 1% by weight. In one aspect, the above monomer component does not substantially contain alkoxyalkyl (meth)acrylate and alkoxypolyalkylene glycol (meth)acrylate ( Content 0~0.3% by weight).

Similarly, the monomer component of the acrylic polymer of this embodiment may contain an alkoxy group-containing monomer at a ratio of less than 20% by weight, or may not contain an alkoxy group-containing monomer. The amount of alkoxy group-containing monomers in the above monomer components is preferably less than 10% by weight, more preferably less than 3% by weight, further preferably less than 1% by weight, and still more preferably In this aspect, the above-mentioned monomer components substantially do not contain alkoxy group-containing monomers (content 0 to 0.3% by weight).

In several aspects, the proportion of the carboxyl group-containing monomer in the monomer component of the acrylic polymer may be, for example, 2% by weight or less, 1% by weight or less, or 0.5% by weight or less ( For example, less than 0.1% by weight). It is also possible to substantially not use a carboxyl group-containing monomer as the monomer component of the acrylic polymer. Here, the term "substantially not using a carboxyl group-containing monomer" means that a carboxyl group-containing monomer is at least not used intentionally. The acrylic polymer with such a composition can easily become highly reliable in water resistance, and can also be resistant to metal corrosion for adherends containing metal.

Furthermore, in a preferred aspect, among the monomer components of the acrylic polymer, the ratio of the hydrophilic monomer is limited. Here, the "hydrophilic monomer" in this specification refers to a carboxyl group-containing monomer, an acid anhydride group-containing monomer, a hydroxyl group-containing monomer, and a nitrogen atom-containing monomer (typically, (meth)propylene amide group-containing monomers such as amide, monomers with nitrogen-containing rings such as N-vinyl-2-pyrrolidinone) and alkoxy group-containing monomers (typically, (meth)acrylic acid Alkoxyalkyl esters and alkoxypolyalkylene glycol (meth)acrylates).

In this aspect, among the monomer components of the acrylic polymer, the ratio of the hydrophilic monomer is preferably 32% by weight or less, for example, it may be 30% by weight or less, or it may be 28% by weight or less. It is not particularly limited. Among the monomer components of the acrylic polymer, the proportion of the hydrophilic monomer may be 1% by weight or more, 10% by weight or more, or 20% by weight or more.

In several aspects, the monomer component constituting the acrylic polymer may contain (meth)acrylate containing an alicyclic hydrocarbon group. This can improve the cohesion of the adhesive and improve the peeling force over time. As the alicyclic hydrocarbon group-containing (meth)acrylate, those exemplified above can be used, and for example, cyclohexyl acrylate or isopropyl acrylate is preferably used.

When using an alicyclic hydrocarbon group-containing (meth)acrylate, the usage amount is not particularly limited. For example, it may be 1 wt% or more, 3 wt% or more, or 5 wt% or more of the total monomer component. In one aspect, the usage amount of the alicyclic hydrocarbon group-containing (meth)acrylate may be 10% by weight or more of the total monomer component, or may be 15% by weight or more. The upper limit of the usage amount of the alicyclic hydrocarbon group-containing (meth)acrylate is suitably about 40% by weight or less, for example, it can be 30% by weight or less, or it can be 25% by weight or less (for example, 15% by weight or less, and then 10% by weight or less) %the following).

The composition of the monomer components constituting the acrylic polymer can be set so that the glass transition temperature Tg calculated by the Fox equation based on the composition of the monomer components is -75°C or more and 10°C or less. In some aspects, the Tg is suitably 0°C or lower, preferably -10°C or lower, and may be -20°C or lower or -30°C or lower from the viewpoint of cohesion, impact resistance, etc. Moreover, the said Tg may be -60 degreeC or more, -50 degreeC or more, -45 degreeC or more, or -40 degreeC or more, for example.

Here, the above-mentioned Fox formula refers to the relational formula between the Tg of the copolymer and the glass transition temperature Tgi of the homopolymer obtained by homopolymerizing each monomer constituting the copolymer, as shown below. 1/Tg＝Σ(Wi/Tgi)

Furthermore, in the above Fox formula, Tg represents the glass transition temperature (unit: K) of the copolymer, Wi represents the weight fraction of monomer i in the copolymer (copolymerization ratio based on weight), and Tgi represents monomer i. The glass transition temperature of the homopolymer (unit: K).

As the glass transition temperature of the homopolymer used in the calculation of Tg, the value described in publicly known documents was used. For example, regarding the monomers listed below, the following values are used as the glass transition temperature of the homopolymer of the monomer.

2-ethylhexyl acrylate -70℃ n-Butyl acrylate -55℃ Isostearyl acrylate -18℃ Methyl methacrylate 105℃ Methyl acrylate 8℃ Cyclohexyl acrylate 15℃ N-vinyl-2-pyrrolidone 54℃ 2-hydroxyethyl acrylate -15℃ 4-hydroxybutyl acrylate -40℃ Dicyclopentyl methacrylate 175℃ Isoacrylate 94℃ Acrylic 106℃ Methacrylic acid 228℃

Regarding the glass transition temperature of homopolymers of monomers other than those exemplified above, the values described in "Polymer Handbook" (3rd edition, John Wiley & Sons, Inc., 1989) are used. When multiple values are recorded in this document, the highest value is used.

Regarding the monomers whose glass transition temperature of the homopolymer is not described in the above-mentioned Polymer Handbook, the value obtained by the following measurement method is used (refer to Japanese Patent Application Laid-Open No. 2007-51271).

Specifically, in a reactor equipped with a thermometer, a stirrer, a nitrogen introduction pipe and a reflux condenser, 100 parts by weight of the monomer, 0.2 parts by weight of azobisisobutyronitrile and 200 parts by weight of ethyl acetate as the polymerization solvent were added. The mixture was stirred for 1 hour while flowing nitrogen gas. After removing the oxygen in the polymerization system in this way, the temperature was raised to 63°C and allowed to react for 10 hours. Then, it was cooled to room temperature to obtain a homopolymer solution with a solid content concentration of 33% by weight. Then, the homopolymer solution was cast-coated on a release liner and dried to prepare a test sample (sheet-shaped homopolymer) with a thickness of about 2 mm. The test sample was punched into a disc shape with a diameter of 7.9 mm, clamped between parallel plates, and a viscoelastic testing machine (ARES, manufactured by Rheometrics) was used to apply shear strain at a frequency of 1 Hz on one side and in the temperature range of -70 to The viscoelasticity was measured in shear mode at 150°C and a heating rate of 5°C/min, and the peak temperature of tan δ was taken as the Tg of the homopolymer.

The acrylic polymer in this embodiment is not particularly limited, but it is preferable that the SP (solubility parameter) value is 23.0 (MJ/m ³ ) ^1/2 or less. The above-mentioned SP value is more preferably 21.0 (MJ/m ³ ) ^1/2 or less (for example, 20.0 (MJ/m ³ ) ^1/2 or less). The lower limit of the above-mentioned SP value is not particularly limited. For example, it is about 10.0 (MJ/m ³ ) ^1/2 or more. It is also suitably about 15.0 (MJ/m ³ ) ^1/2 or more, and preferably it is 18.0 (MJ/m 3 ) 1/2 or more. ³ ) ^1/2 or more.

Furthermore, the SP value of acrylic polymer can be calculated according to Fedors [Reference "Polymer Engineering and Science (POLYMER ENG. &SCI.)", Vol. 14, No. 2 (1974), pp. 148-154 ], that is, the formula: SP value δ = (ΣΔe/ΣΔv) ^1/2 (In the above formula, Δe is the evaporation energy Δe of each atom or atomic group at 25°C, and Δv is the mole of each atom or atomic group at the same temperature. volume). The acrylic polymer having the above SP value can be obtained by appropriately determining the monomer composition based on the technical knowledge of the operator.

The above-mentioned adhesive composition contains monomer components having the above-mentioned composition in the form of polymer, non-polymer (that is, a form in which polymerizable functional groups have not reacted), or a mixture thereof. The above-mentioned adhesive composition may be a water-dispersed adhesive composition in which an adhesive (adhesive component) is dispersed in water, a solvent-based adhesive composition in which an adhesive is contained in an organic solvent, or a solvent-based adhesive composition in which the adhesive is dispersed by ultraviolet rays or Active energy ray-hardening adhesive compositions prepared by hardening active energy rays such as radiation to form adhesives, hot-melt adhesive compositions that are applied in a heated molten state and cooled to near room temperature to form adhesives, etc. form. The adhesive composition of a preferred embodiment is a solvent-based adhesive composition or a solvent-free adhesive composition. The solvent-free adhesive composition includes an active energy ray-hardening adhesive composition and a hot-melt adhesive composition.

During polymerization, a known or conventional thermal polymerization initiator or photoradical polymerization initiator may be used depending on the polymerization method or polymerization state. Such polymerization initiators can be used alone or in combination of two or more types as appropriate.

The thermal polymerization initiator is not particularly limited. For example, azo-based polymerization initiators, peroxide-based initiators, redox-based initiators that are a combination of a peroxide and a reducing agent, Substitute ethane initiator, etc.

More specifically, examples include: 2,2'-azobisisobutyronitrile (AIBN), 2,2'-azobis(2-methylpropionamidine)disulfate, 2,2'-azobisisobutyronitrile (AIBN), Azobis(2-amidinopropane)dihydrochloride, 2,2'-Azobis[2-(5-methyl-2-imidazolin-2-yl)propane]dihydrochloride, 2,2 '-Azobis(N,N'-dimethyleneisobutylamidine), 2,2'-Azobis[N-(2-carboxyethyl)-2-methylpropionamidine] hydrate, etc. Azo initiators; such as potassium persulfate, ammonium persulfate and other persulfates; peroxide initiators such as benzyl peroxide, tert-butyl hydroperoxide, hydrogen peroxide, etc.; such as phenyl substitution Ethane and the like replace the ethane-based initiator; for example, the combination of persulfate and sodium bisulfite, the combination of peroxide and sodium ascorbate, and other redox-based initiators; etc., but are not limited to these. In addition, thermal polymerization can be preferably carried out at a temperature of about 20 to 100°C (typically 40 to 80°C), for example.

The photoradical polymerization initiator is not particularly limited, and examples include: 1-[4-(2-hydroxyethoxy)-phenyl]-2-hydroxy-2-methyl-1-propane-1 -Ketone, 1-hydroxy-cyclohexyl-phenyl-one, benzophenone, 2,2-dimethoxy-1,2-diphenylethan-1-one, 2,4,6-tri Methyl-diphenyl-phosphine oxide, 2,4,6-trimethylbenzyl-phenylethoxy-phosphine oxide, 2-benzyl-2-dimethylamino-1 -(4-𠰌linylphenyl)-butanone-1,2-hydroxy-2-methyl-1-phenyl-propan-1-one, 2-methyl-1-(4-methylthio) Phenyl)-2-𠰌linylpropane-1-one, benzoin methyl ether, benzoin ethyl ether, benzoin isobutyl ether, benzoin isopropyl ether, bis(2,4,6-trimethylbenzoyl)-benzene Phosphine oxide, 2-hydroxy-2-methyl-[4-(1-methylvinyl)phenyl]propanol oligomer, 2-hydroxy-2-methyl-1-phenyl-1-propanone , isopropyl-9-oxosulfide𠮿 , Methyl o-benzoate, [4-(methylphenylthio)phenyl]phenylmethane, 2,4-diethyl-9-oxysulfide𠮿 , 2-chloro-9-oxosulfide𠮿 , Ethyl anthraquinone, benzophenone ammonium salt, 9-oxosulfide𠮿 Ammonium salt, bis(2,6-dimethylbenzoyl)-2,4,4-trimethyl-pentylphosphine oxide, 2,4,6-trimethylbenzophenone, 4-methyl benzophenone, 4,4'-bisdiethylaminobenzophenone, 1,4-dibenzoylbenzene, 10-butyl-2-chloroacridone, 2,2'-bis (O-chlorophenyl)-4,5,4',5'-tetrakis(3,4,5-trimethoxyphenyl)-1,2'-biimidazole, 2,2'-bis(o-chlorobenzene base)-4,5,4',5'-tetraphenyl-1,2'-biimidazole, 2-benzoylnaphthalene, 4-benzoylbiphenyl, 4-benzoyldiphenyl Ether, propylated benzophenone, bis(eta5-2,4-cyclopentadien-1-yl)-bis[2,6-difluoro-3-(1H-pyrrol-1-yl)-benzene base] titanium, o-toluyl benzoate, ethyl p-dimethylaminobenzoate, isoamyl ethyl p-dimethylaminobenzoate, active tertiary amine, carbazole-benzophenone series Photopolymerization initiator, acridine-based photopolymerization initiator, tristridium-based photopolymerization initiator, benzyl-based photopolymerization initiator, etc. These can be used individually or in combination of 2 or more types.

The usage amount of such thermal polymerization initiator or photo radical polymerization initiator can be a usual usage amount depending on the polymerization method, polymerization state, etc., and is not particularly limited. For example, about 0.001 to 5 parts by mass (typically about 0.01 to 2 parts by mass, for example, about 0.01 to 1 part by mass) of the polymerization initiator can be used relative to 100 parts by mass of the monomer to be polymerized.

If necessary, various previously known chain transfer agents (which can also be understood as molecular weight regulators or polymerization degree regulators) can be used in the above polymerization. As the chain transfer agent, thiols such as n-dodecanethiol, tertiary-dodecanethiol, thioglycolic acid, and α-thioglycerol can be used. Alternatively, a chain transfer agent containing no sulfur atoms (non-sulfur chain transfer agent) may be used.

Specific examples of non-sulfur chain transfer agents include: anilines such as N,N-dimethylaniline and N,N-diethylaniline; terpenes such as α-pinene and terpinene; α- Styrenes such as methylstyrene and α-methylstyrene dimer; compounds with benzylidene groups such as dibenzylidene acetone, cinnamyl alcohol and cinnamic aldehyde; hydroquinones such as hydroquinone and naphthohydroquinone; benzene Quinones such as quinone and naphthoquinone; olefins such as 2,3-dimethyl-2-butene and 1,5-cyclooctadiene; alcohols such as phenol, benzyl alcohol and allyl alcohol; diphenylbenzene, Triphenylbenzene and other benzyl hydrogens; etc.

A chain transfer agent can be used individually by 1 type or in combination of 2 or more types. When a chain transfer agent is used, the usage amount may be about 0.01 to 1 part by mass relative to 100 parts by mass of the monomer component. The technology of this embodiment can also be preferably implemented without using a chain transfer agent.

The molecular weight of the acrylic polymer suitably obtained by the various polymerization methods mentioned above is not particularly limited and can be set to an appropriate range in accordance with the required performance. The weight average molecular weight (Mw) of the acrylic polymer is usually about 10×10 ⁴ or more (for example, 20×10 ⁴ or more). From the viewpoint of achieving a well-balanced cohesion force and adhesive strength, it is preferably more than 30×10 ⁴ . From the viewpoint of obtaining good bonding reliability even in a high-temperature environment, an acrylic polymer of one aspect preferably has a polypropylene content of 40×10 ⁴ or more (typically about 50×10 ⁴ or more, for example, about 55×10 ⁴ or above) Mw. According to a preferred aspect of the technology of this embodiment, gelation can be suppressed by designing the monomer composition. Therefore, an appropriate solid component concentration can be set, and a high molecular weight body in the above range can be obtained with high productivity. The upper limit of the Mw of the acrylic polymer may generally be about 500×10 ⁴ or less (for example, about 150×10 ⁴ or less). The above-mentioned Mw may be approximately 75×10 ⁴ or less.

Mw here refers to the standard polystyrene-converted value obtained by gel permeation chromatography (GPC). As a GPC device, for example, the model name "HLC-8320GPC" (column: TSKgelGMH-H(S), manufactured by Tosoh Corporation) may be used. The same applies to the following examples. The above-mentioned Mw may be the Mw of the acrylic polymer in any one of the adhesive composition and the adhesive layer.

The adhesive composition in some embodiments may be an active energy ray-curable adhesive composition. Examples of active energy rays here include light such as ultraviolet rays, visible rays, infrared rays, or radiation such as alpha rays, beta rays, gamma rays, electron beams, neutron rays, and X-rays. Examples thereof include those that can cause polymerization reactions, The energy line of chemical reactions such as cross-linking reaction and decomposition of initiator.

In the adhesive composition according to one embodiment of the present invention, in order to be able to change color or color at any time, it is preferable that the time point at which the active energy ray curing type adhesive composition is cured is different from the time point at which it changes color or color. Take control. That is, it is preferable that the active energy ray curable adhesive composition reacts with the following photoacid generator or photobase generator at the timing of chemical reactions such as polymerization reaction, crosslinking reaction, or decomposition of the initiator. Select the type of each component in such a way that the leuco pigment changes color or the points of coloring do not overlap. Furthermore, in other words, it is preferable that the energy ray causing the chemical reaction such as the above-mentioned polymerization reaction, cross-linking reaction, decomposition of the initiator and the energy ray causing the reaction of the following photoacid generator or photobase generator have different reactions. The above compositions are designed in a wavelength manner.

A preferred example of the active energy ray curable adhesive composition is a photocurable adhesive composition. The photocurable adhesive composition has the advantage that even a thick adhesive layer can be easily formed. Among them, an ultraviolet curable adhesive composition is preferred.

The photocurable adhesive composition typically contains at least a part of the monomer components of the composition in the form of a polymer (it may be part of the type of monomer or part of the component). The polymerization method for forming the above-mentioned polymer is not particularly limited, and various conventionally known polymerization methods can be suitably used. For example, thermal polymerization such as solution polymerization, emulsion polymerization, and block polymerization (typically carried out in the presence of a thermal polymerization initiator); photopolymerization carried out by irradiating light such as ultraviolet rays (typically carried out in the presence of light) can be suitably used. in the presence of a free radical polymerization initiator); radiation polymerization by irradiating β-rays, γ-rays and other radiation; etc. Among them, photopolymerization is preferred.

In a preferred embodiment, the photocurable adhesive composition contains a partial polymer of monomer components. This partial polymer is typically a mixture of a polymer derived from monomer components and unreacted monomers, and is preferably in the form of a slurry (viscous liquid). Hereinafter, some polymers with this property may be referred to as "monomer slurry" or simply "slurry". The polymerization method when partially polymerizing the monomer component is not particularly limited, and the various polymerization methods described above can be appropriately selected and used. From the viewpoint of efficiency or simplicity, photopolymerization may be preferred. In the case of photopolymerization, the polymerization conversion rate (monomer conversion rate) of the monomer component can be easily controlled by polymerization conditions such as the amount of light irradiation (light quantity).

The polymerization conversion rate of the monomer mixture in the above-mentioned partial polymer is not particularly limited. The polymerization conversion rate may be, for example, approximately 70% by weight or less, preferably approximately 60% by weight or less. From the viewpoint of ease of preparation or coating properties of the adhesive composition containing the above-mentioned partial polymer, the polymerization conversion rate is usually about 50% by weight or less, preferably about 40% by weight or less (for example, about 35% by weight). %the following). The lower limit of the polymerization conversion rate is not particularly limited, but is typically about 1% by weight or more, and usually about 5% by weight or more.

The adhesive composition containing a partial polymer of monomer components can be prepared by using an appropriate polymerization method (such as a photopolymerization method) to contain the total amount of monomers used in the preparation of the adhesive composition. The mixture is obtained by partial polymerization. In addition, the adhesive composition containing a partial polymer of the monomer component may also be a partial polymer or a complete polymer of a monomer mixture containing a part of the monomer components used in the preparation of the adhesive composition and the remainder. A mixture of monomer components or partial polymers thereof. In addition, the so-called "complete polymer" in this specification means that the polymerization conversion rate exceeds 95% by weight.

(leuco pigment) An adhesive composition according to one embodiment of the present invention contains a leuco pigment. In this specification, a leuco pigment refers to an organic pigment whose color tone changes reversibly along with oxidation and reduction. The absorption wavelength may change depending on the pH value. More specifically, it refers to a reduced pigment having one or more hydrogen atoms that forms a pigment and develops color by adding electrons or removing electrons. Leuco pigments are colorless or have a faint color in neutral or alkaline media. However, if they react with acidic substances or electron-withdrawing substances, the lactone ring becomes open and colored as shown in Figure 1. By selecting leuco pigments that are essentially colorless or have a faint color before removing electrons, the change in coloration can be observed significantly.

In this embodiment, the leuco pigment is colored using an acid generated by irradiating active energy rays to a photoacid generator described below.

In addition, in the present embodiment, the leuco pigment can be decolorized by ring-closing the lactone ring by reacting with a base after the lactone ring becomes a ring-opened state and is colored. The above-mentioned base can also be generated by irradiating active energy rays to the photobase generator described below.

Examples of the leuco dye of the present embodiment include phthalide dyes (indolophthalide series or triphenylmethane phthalide series, etc.), fluorescent yellow matrix dyes, triphenylmethane dyes, and thiophene dyes. , auramine dyes, spiropyran dyes and other leuco compounds.

As the leuco pigment, from the viewpoint of excellent color development, at least one leuco pigment selected from the group consisting of phthalide dyes and fluorescent yellow matrix dyes is particularly preferred.

Specific examples of leuco pigments include the following compounds.

2'-anilino-6'-(N,N-dipentan-1-ylamine)-3'-methyl-3H-spiro[isobenzofuran-1,9'-𠮿 ]-3-one, 2-anilino-3-methyl-6-dibutylamine fluorescent yellow matrix, 2-anilino-3-methyl-6-dipentylamine fluorescent yellow matrix, 2- Anilino-3-methyl-6-[ethyl(4-methylphenyl)amino]fluorescein matrix, 3,3-bis(p-dimethylaminophenyl)-phthalide, 3,3 -Bis(p-dimethylaminophenyl)-6-dimethylaminophthalide (alias: crystal violet lactone), 3,3-bis(p-dimethylaminophenyl)-6-diethylamino Phthalide, 3,3-bis(p-dimethylaminophenyl)-6-chlorophthalide, 3,3-bis(p-dibutylaminophenyl)phthalide, 3-cyclohexylamine-6- Chlorofluorescein matrix, 3-dimethylamino-5,7-dimethylfluorescein matrix, 3-(N-methyl-N-isobutyl)-6-methyl-7-anilinofluorescein Photo yellow matrix, 3-(N-ethyl-N-isoamyl)-6-methyl-7-anilino fluorescent yellow matrix, 3-diethylamino-7-chlorofluor yellow matrix, 3- Diethylamine-7-methylfluorescein yellow matrix, 3-diethylamino-7,8-benzofluorescein yellow matrix, 3-diethylamino-6-methyl-7-chlorofluorescein yellow Parent, 3-(N-p-tolyl-N-ethylamino)-6-methyl-7-anilino fluorescent yellow parent, 3-pyrrolidinyl-6-methyl-7-anilino fluorescent yellow Parent, 2-{N-(3'-trifluoromethylphenyl)amino}-6-diethylamine fluorescent yellow parent, 2-{3,6-bis(diethylamino)-9- (o-Chloroaniline)𠮿 benzoic acid lactam}, 3-diethylamino-6-methyl-7-(m-trichloromethylanilino) fluorescent yellow matrix, 3-diethylamino-7-(o-chloroanilino) ) Fluorescent yellow matrix, 3-dibutylamine-7-(o-chloroanilino) Fluorescent yellow matrix, 3-(N-methyl-N-pentylamine)-6-methyl-7-anilino Fluorescent yellow matrix, 3-(N-methyl-N-cyclohexylamine)-6-methyl-7-anilino fluorescent yellow matrix, 3-diethylamino-6-methyl-7-aniline base fluorescent yellow matrix, 3-diethylamino-6-methyl-7-(2',4'-dimethylanilino) fluorescent yellow matrix, 3-(N,N-diethylamino) -5-Methyl-7-(N,N-dibenzylamino)fluorescein yellow matrix, benzyl leuco methylene blue, 6'-chloro-8'-methoxy-benzoindolyl-spiropyridine Pyran, 6'-bromo-3'-methoxy-benzoindolyl-spiropyran, 3-(2'-hydroxy-4'-dimethylaminophenyl)-3-(2'-methyl Oxy-5'-chlorophenyl)phthalide, 3-(2'-hydroxy-4'-dimethylaminophenyl)-3-(2'-methoxy-5'-nitrophenyl) Phthalide, 3-(2'-hydroxy-4'-diethylaminophenyl)-3-(2'-methoxy-5'-methylphenyl) phthalide, 3-(2'-methyl Oxy-4'-dimethylaminophenyl)-3-(2'-hydroxy-4'-chloro-5'-methylphenyl)phthalide, 3-𠰌linyl-7-(N-propyl -trifluoromethylanilinyl)fluorescein base, 3-pyrrolidinyl-7-trifluoromethylanilinylfluorescein base, 3-diethylamino-5-chloro-7-(N-benzyl) (trifluoromethylanilinyl)fluorescein base, 3-pyrrolidinyl-7-(di-chlorophenyl)methylaminofluorescein base, 3-diethylamino-5-chloro-7 -(α-phenylethylamine)fluorescein precursor, 3-(N-ethyl-p-toluidino)-7-(α-phenylethylamine)fluorescein precursor, 3-diethylamine Base-7-(o-methoxycarbonylanilino)fluorescein precursor, 3-diethylamino-5-methyl-7-(α-phenylethylamine)fluorescein precursor, 3-diethylamine Amino-7-piperidinyl fluorescent yellow matrix, 2-chloro-3-(N-methyltoluidinyl)-7-(p-n-butylanilinyl) fluorescent yellow matrix, 3-(N-methyl (N-isopropylamine)-6-methyl-7-anilino fluorescent yellow matrix, 3-dibutylamine-6-methyl-7-anilino fluorescent yellow matrix, 3,6-bis( Dimethylamino)benzo(9,3')-6'-dimethylaminophthalide, 3-(N-benzyl-N-cyclohexylamine)-5,6-benzo-7-α -Naphthylamine-4'-bromofluorescein precursor, 3-diethylamino-6-chloro-7-anilinofluorescein precursor, 3-{N-ethyl-N-(2-ethoxy Propyl)amino}-6-methyl-7-anilino fluorescent yellow matrix, 3-{N-ethyl-N-tetrahydrofuranmethylamino}-6-methyl-7-anilino fluorescent yellow Parent, 3-diethylamino-6-methyl-7-m-trimethylanilino-4',5'-benzofluorescein yellow parent, 3-(p-dimethylaminophenyl)-3-{1 ,1-bis(p-dimethylaminophenyl)ethylene-2-yl}phthalide, 3-(p-dimethylaminophenyl)-3-{1,1-bis(p-dimethylaminophenyl) )Ethylene-2-yl}-6-dimethylaminophthalide, 3-(p-dimethylaminophenyl)-3-(1-p-dimethylaminophenyl-1-phenylethene-2- base) phthalide, 3-(p-dimethylaminophenyl)-3-(1-p-dimethylaminophenyl-1-p-chlorophenylethene-2-yl)-6-dimethylaminobenzene Phthalate, 3-(4'-dimethylamino-2'-methoxy)-3-(1''-p-dimethylaminophenyl-1''-p-chlorophenyl-1'',3 ''-Butadien-4''-yl)benzophthalide, 3-(4'-dimethylamino-2'-benzyloxy)-3-(1''-p-dimethylaminobenzene -1''-phenyl-1'',3''-butadien-4''-yl)benzophthalide, 3-dimethylamino-6-dimethylamino-fluorine-9- Spiro-3'(6'-dimethylamino)phthalide, 6-(diethylamino)-2-[(3-trifluoromethyl)anilino] 𠮿 -9-Spiro-3'-phthalide, 3,3-bis{2-(p-dimethylaminophenyl)-2-(p-methoxyphenyl)vinyl}-4,5,6,7 -Tetrachlorophthalide, 3-bis{1,1-bis(4-pyrrolidinylphenyl)ethylene-2-yl}-5,6-dichloro-4,7-dibromophthalide, bis(p Dimethylaminostyryl)-1-naphthalenesulfonylmethane, bis(p-dimethylaminostyryl)-1-p-toluenesulfonylmethane.

The leuco pigment of this embodiment can be used individually by 1 type, and can also be used in mixture of 2 or more types.

In the embodiment of the present invention, the leuco pigment is preferably 0.01 to 30 parts by mass, more preferably 0.1 to 30 parts by mass, and still more preferably 0.1 to 20 parts by mass per 100 parts by mass of the above-mentioned base polymer. , and more preferably 1 to 10 parts by mass. By setting it within the above range, discoloration or coloration due to the leuco pigment can be clearly observed.

(Photoacid generator) An adhesive composition according to one embodiment of the present invention contains a photoacid generator. The so-called photoacid generator in this specification refers to activities that are not limited to irradiation of light such as ultraviolet rays, visible rays, and infrared rays, or irradiation of radiation such as alpha rays, beta rays, gamma rays, electron beams, neutron rays, and X-rays. In the case of energy rays, acid (cationic) compounds can also be produced. The photoacid generator generates acid after irradiation with the above-mentioned active energy rays. Therefore, by using it together with the above-mentioned leuco pigment, the adhesive layer or adhesive sheet obtained by using the above-mentioned adhesive composition can be used at any time. Discoloration or staining.

The photoacid generator is not particularly limited as long as it is a compound that can generate an acid (cation) by irradiating active energy rays. Examples thereof include: sulfonium salt-based compounds, iodonium salt-based compounds, and aromatic N-oxyl groups. Carboxylimine sulfonate esters, sulfonate ester compounds and halomethyl-substituted mesitylene derivatives, etc.

As the photoacid generator, from the viewpoint of good compatibility with other components of the adhesive composition of the present invention, it is particularly preferably selected from the group consisting of sulfonium salt-based compounds, iodonium salt-based compounds, and aromatic N-oxyl chelates. At least one compound in the group consisting of sulfamic acid esters.

Specific examples of the sulfonium salt-based compounds include dimethylbenzoylmethylsulfonium, dimethylbenzylsulfonium, dimethyl-4-hydroxyphenylsulfonium, and dimethyl-4-hydroxy. Naphthyl sulfonium, dimethyl-4,7-dihydroxynaphthyl sulfonium, dimethyl-4,8-dihydroxynaphthyl sulfonium, triphenyl sulfonium, p-tolyldiphenyl sulfonium, p-tert-butyl Phenyldiphenylsulfonate, diphenyl-4-phenylthiophenylsulfonate and other cations are combined with chloride, bromide, p-toluenesulfonate, trifluoromethanesulfonate, tetrafluoroborate, tetrakis(pentafluorobenzene) Base) salts of anions such as borate, tetrakis (pentafluorophenyl) gallate, hexafluorophosphate, hexafluoroarsenate, hexafluoroantimonate, and nonafluorobutanesulfonate.

Examples of the iodonium salt compounds include diphenyl iodonium, bis(p-chlorophenyl) iodonium, xylyl iodonium, bis(p-tert-butylphenyl)iodium, and p-isopropylphenyl-p-methyl Bis(m-nitrophenyl)quinodium, p-tert-butylphenylphenylplatinum, p-methoxyphenylphenylplatinum, bis(p-methoxyphenyl)quinodium, p-octyloxide Cations such as phenyl phenyl iodide and p-phenoxy phenyl phenyl iodide and chloride, bromide, p-toluenesulfonate, trifluoromethanesulfonate, tetrafluoroborate, and tetrakis(pentafluorophenyl)borate , salts of anions such as tetrakis (pentafluorophenyl) gallate, hexafluorophosphate, hexafluoroarsenate, hexafluoroantimonate, and nonafluorobutanesulfonate.

Examples of the aromatic N-oxycarboxylimide sulfonate include N-(trifluoromethylsulfonyloxy)succinimide and N-(trifluoromethylsulfonyloxy)o-phthalate. Dimethylimide, N-(trifluoromethylsulfonyloxy)diphenylmaleimide, N-(trifluoromethylsulfonyloxy)bicyclohept-5-ene-2, 3-dicarboxyl imine and N-(trifluoromethylsulfonyloxy)naphthoyl imine, etc.

Examples of the sulfonate compound include benzoin tosylate, α-hydroxymethylbenzoin tosylate, o-nitrobenzyl p-toluenesulfonate, and p-nitrobenzyl-9,10-diethyl Oxyanthracene-2-sulfonate, etc. Specific examples of halomethyl-substituted mesosine derivatives include: 2,4,6-tris(trichloromethyl) mesosine, 2-methyl-4,6-bis(trichloromethyl) Mesosine, 2-phenyl-4,6-bis(trichloromethyl)meso, 2-methyl-4,6-bis(tribromomethyl)meso, etc.

In an embodiment of the present invention, the photoacid generator is preferably 0.001 to 30 parts by mass, more preferably 0.01 to 25 parts by mass, and still more preferably 0.1 to 30 parts by mass per 100 parts by mass of the above-mentioned base polymer. parts, and more preferably 0.1 to 20 parts by mass. By setting it within the above range, acid can be efficiently generated by active energy ray irradiation, and discoloration or coloring can be observed significantly.

(Photobase generator) The adhesive composition according to one embodiment of the present invention may contain a photobase generator. The so-called photobase generator refers to the case of irradiating active energy rays such as alpha rays, beta rays, gamma rays, electron beams, neutron rays, and Base (anion) compounds can also be produced. The photobase generator generates a base after irradiation with the above-mentioned active energy rays. Therefore, after coloring the leuco pigment, the leuco pigment can be reduced at any time to make the coloring disappear.

Furthermore, when the adhesive composition according to one embodiment of the present invention contains a photobase generator, it is preferable that the photobase generator does not cause the photoacid generator to generate acid by irradiation with active energy rays. The method of generating a base at the same time point is to set the combination of the above-mentioned photoacid generator and photobase generator. That is, it is preferable to design the photobase generator in such a manner that it generates a base by using an active energy ray of a different type from the active energy ray required for the photoacid generator to generate an acid.

The photobase generator is not particularly limited as long as it is a compound that can generate a base (anion) by irradiating active energy rays. Examples include transition metal complexes and compounds having a benzylcarbamate structure. , compounds with ortho-substituted nitrobenzene structures, oximes, imidazole derivatives, benzoin compounds, compounds with N-carboxylated aromatic amine groups, compounds with N-carboxylated aromatic amine groups, compounds with alkane Oxybenzylcarbamate-based compounds, compounds with 1,4-dihydropyridine skeleton, oxime esters, quaternary ammonium salts, etc.

The photobase generator of this embodiment is preferably 0.001 to 30 parts by mass, more preferably 0.01 to 25 parts by mass, and still more preferably 0.1 to 20 parts by mass per 100 parts by mass of the above-mentioned base polymer. By setting it within the above range, alkali can be efficiently generated by active energy ray irradiation, and the colored adhesive sheet can be decolorized.

(Peel strength increasing agent) The adhesive composition according to one embodiment of the present invention may contain a peeling force improving agent. As the above-mentioned peeling force increasing agent, a material that can perform the following functions can be appropriately selected and used: after the surface (adhesive surface) of the adhesive layer formed of the above-mentioned adhesive composition is attached to the adherend, the adhesive sheet can be self-adhered. The peeling force of the body increases. As the peeling force increasing agent, for example, a known silane coupling agent can be used. The peeling force increasing agent is preferably contained in the adhesive composition (or adhesive layer) in a free form. Typically, it is preferable that the peeling force increasing agent does not chemically bond with other components that may be contained in the adhesive composition (or adhesive layer). The peeling force improving agent contained in the adhesive composition in this form can effectively help improve the peeling force.

Silane coupling agents are typically compounds containing a functional group X and a functional group Y in one molecule, and the functional group X is an alkoxysilyl group. The above-mentioned alkoxysilyl group is a functional group having at least one alkoxy group on the silicon atom. By supplying a silane coupling agent to the surface of the adhesive layer after being attached to the adherend, the silanol groups generated by the hydrolysis of the alkoxy groups react with the hydroxyl groups on the surface of the adherend, thereby allowing the adhesive sheet to self-adhere The peeling force of the body increases. The above-mentioned alkoxysilyl group is hydrolyzed to generate a silanol group that reacts with the hydroxyl group on the surface of the adherend. Therefore, the above-mentioned alkoxysilyl group is a radical precursor that reacts with the above-mentioned hydroxyl group.

The alkoxy group constituting the above-mentioned alkoxysilyl group is typically a methoxy group or an ethoxy group. More hydrolyzable methoxy groups are generally preferred. The above-mentioned alkoxysilyl group may be a trialkoxysilyl group or a dialkoxysilyl group. From the viewpoint of improving the peeling force increasing effect, in some aspects, a silane coupling agent having a trialkoxysilyl group can be preferably used.

The functional group Y can be, for example, an epoxy group, an amine group, an isocyanate group (which can constitute an isocyanurate compound), an acetyl acetyl group, a (meth)acrylyl group, a mercapto group, a vinyl group, a halogenated alkyl group, and the like. Examples of the silane coupling agent having such a functional group Y include, for example, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropyltriethoxysilane, and 3-glycidoxysilane. Silane coupling agents containing epoxy groups such as methylpropylmethyldimethoxysilane and 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane; for example, 3-aminopropyltrimethoxysilane , N-(2-aminoethyl)3-aminopropyltrimethoxysilane, N-(2-aminoethyl)3-aminopropylmethyldimethoxysilane and other amine-containing Silane coupling agents; such as 3-isocyanatopropyltriethoxysilane, tris(trimethoxysilylpropyl)isocyanurate and other isocyanate group-containing silane coupling agents; such as acetyl acetyl group-containing silane coupling agents Silane coupling agents containing acetyl acetyl groups such as silane; for example, 3-methacrylyloxypropyltrimethoxysilane, 3-methacrylyloxypropyltriethoxysilane, 3-acrylyloxysilane Silane coupling agents containing (meth)acrylyl groups such as oxypropyltrimethoxysilane; silane coupling agents containing vinyl groups such as vinyltrimethoxysilane and vinyltriethoxysilane; 3-methylpropylene Silane coupling agents containing mercapto groups such as hydroxypropylmethyldimethoxysilane and 3-methacryloyloxypropyltrimethoxysilane; silane coupling agents containing halogenated alkyl groups such as 3-chloropropyltrimethoxysilane. Silane coupling agent; etc. Among them, epoxy group-containing ones such as glycidoxypropyltrialkoxysilane (such as 3-glycidoxypropyltrimethoxysilane or 3-glycidoxypropyltriethoxysilane) are preferred. Silane coupling agent.

As the silane coupling agent, one having a functional group Y that reacts with the functional group y contained in the adhesive layer can be used. From the viewpoint of reactivity at normal temperature, a combination of a silane coupling agent having a carboxyl group as the functional group Y and an epoxy group as the functional group Y can be cited. Examples of other combinations include: combinations of amine groups and epoxy groups, combinations of hydroxyl groups and epoxy groups, combinations of carboxyl groups and amine groups, combinations of isocyanate groups and amine groups, combinations of sulfo groups and amine groups, and the like. On the other hand, in some aspects, as an adhesive composition, by maintaining the peeling force improving agent in a free state in the adhesive composition, the peeling force improving agent can easily migrate to the surface. That is, it may be one that does not have a functional group y (such as a carboxyl group) that reacts with the functional group Y (such as an epoxy group) of the silane coupling agent.

The molecular weight (chemical formula weight) of the silane coupling agent is not particularly limited, but may be about 120 to 1,000, for example. Generally, from the viewpoint of ease of adjustment of rework time or mobility to the adhesive surface, a silane coupling agent with a molecular weight of 180 or more, 200 or more, or 220 or more is generally preferred. For the same reason, a silane coupling agent with a molecular weight of 800 or less, 600 or less, 400 or less, or 300 or less is preferred. In several aspects, a silane coupling agent with a molecular weight of 200 to 300 can be preferably used. As the value of the molecular weight of the silane coupling agent, a value calculated based on the structural formula of the silane coupling agent is used. Alternatively, the manufacturer's name value can be used.

The amount of the peeling force increasing agent (eg, silane coupling agent) contained in the adhesive composition according to one embodiment of the present invention is set in such a manner that the desired use effect can be obtained, and is not particularly limited. The amount of the peeling force increasing agent may be, for example, 0.005 parts by mass or more per 100 parts by mass of the base polymer contained in the adhesive composition. The content of the peeling force increasing agent per 100 parts by mass of the base polymer is usually 0.05 parts by mass or more, and may be 0.10 parts by mass or more, 0.20 parts by mass or more, or 0.30 parts by mass or more. By increasing the content of the peeling force increasing agent, the peeling force increasing effect can be exerted.

In addition, depending on how the peeling force increasing agent is used, if the time until the peeling force increases due to the passage of time at room temperature is too short, the time for rework becomes too short, and the step management may become complicated. Undesirable situation. From this point of view, in several aspects, the content of the peeling force increasing agent per 100 parts by mass of the base polymer in the adhesive composition may be, for example, 5 parts by mass or less or 3 parts by mass or less. , may be 1 part by mass or less, or may be 0.7 part by mass or less (for example, 0.5 part by mass or less).

(cross-linking agent) The adhesive composition according to one embodiment of the present invention aims at cross-linking within the main adhesive layer or cross-linking the adhesive layer and its adjacent surface, and may contain a cross-linking agent if necessary. The type of cross-linking agent is not particularly limited and can be selected from previously known cross-linking agents, for example, according to the composition of the adhesive composition, in a manner that allows the cross-linking agent to exert an appropriate cross-linking function in the adhesive layer.

Examples of cross-linking agents that can be used include: isocyanate-based cross-linking agents, epoxy-based cross-linking agents, oxazoline-based cross-linking agents, aziridine-based cross-linking agents, carbodiimide-based cross-linking agents, Melamine cross-linking agents, urea cross-linking agents, metal alkoxide cross-linking agents, metal chelate cross-linking agents, metal salt cross-linking agents, hydrazine cross-linking agents and amine cross-linking agents, etc. These can be used individually by 1 type or in combination of 2 or more types.

As the isocyanate cross-linking agent, a bifunctional or higher polyfunctional isocyanate compound can be used. Examples include: aromatic isocyanates such as toluene diisocyanate, xylene diisocyanate, polymethylene polyphenyl diisocyanate, tris(p-isocyanatophenyl)thiophosphate, diphenylmethane diisocyanate; isocyanate; Alicyclic isocyanates such as phorone diisocyanate; aliphatic isocyanates such as hexamethylene diisocyanate. Examples of commercially available products include: trimethylolpropane/toluene diisocyanate terpolymer adduct (manufactured by Tosoh Corporation, trade name "Coronate L"), trimethylolpropane/hexamethylene diisocyanate terpolymer Isocyanate adducts such as isocyanate adducts (manufactured by Tosoh Corporation, trade name "Coronate HL"), isocyanurate compounds of hexamethylene diisocyanate (manufactured by Tosoh Corporation, trade name "Coronate HX"), etc.

As the epoxy cross-linking agent, those having two or more epoxy groups per molecule can be used without particular limitation. An epoxy cross-linking agent having 3 to 5 epoxy groups per molecule is preferred. Specific examples of the epoxy cross-linking agent include: N,N,N',N'-tetraglycidyl-m-xylylenediamine, 1,3-bis(N,N-diglycidylamine methyl)cyclohexane, 1,6-hexanediol diglycidyl ether, polyethylene glycol diglycidyl ether, polyglycerol polyglycidyl ether, etc. Examples of commercially available epoxy cross-linking agents include: "TETRAD-X" and "TETRAD-C" manufactured by Mitsubishi Gas Chemical Company, trade names "EPICLON CR-5L" and Nagase chemteX manufactured by DIC Corporation The product is manufactured under the trade name "DENACOL EX-512" by the company, and the product is manufactured under the trade name "TEPIC-G" by Nissan Chemical Industries, Ltd.

As the tetrazoline cross-linking agent, those having one or more tetrazoline groups per molecule can be used without particular limitation.

Examples of aziridine-based crosslinking agents include: trimethylolpropane tris[3-(1-aziridinyl)propionate], trimethylolpropane tris[3-(1-(2 -Methyl)aziridinylpropionate)], etc.

As the carbodiimide cross-linking agent, a low molecular compound or a high molecular compound having two or more carbodiimide groups can be used.

In several aspects, peroxide can be used as the cross-linking agent. Examples of the peroxide include di(2-ethylhexyl)peroxydicarbonate, di(4-tert-butylcyclohexyl)peroxydicarbonate, dibutyl peroxydicarbonate, and peroxydicarbonate. Oxidized tert-butyl neodecanoate, tert-hexyl peroxypivalate, tert-butyl peroxypivalate, dilauryl peroxide, di-n-octyl peroxide, isobutyric peroxide 1,1 ,3,3-tetramethylbutyl ester, dibenzoyl peroxide, etc. Among them, examples of peroxides having particularly excellent cross-linking reaction efficiency include di(4-tert-butylcyclohexyl) peroxydicarbonate, dilauryl peroxide, dibenzoyl peroxide, and the like. .

Furthermore, when peroxide is used as the above-mentioned polymerization initiator, the remaining peroxide that has not been used for the polymerization reaction may be used for the cross-linking reaction. In this case, the remaining amount of peroxide is measured, and when the ratio of peroxide does not satisfy the specific amount, peroxide may be added so as to achieve the specific amount if necessary. The peroxide can be measured by the method described in Japanese Patent No. 4971517.

The content of the cross-linking agent (when two or more cross-linking agents are contained, the total amount thereof) is not particularly limited. From the viewpoint of realizing an adhesive that exhibits adhesive properties such as adhesion and cohesion in a well-balanced manner, the content of the cross-linking agent is usually approximately 5 parts by mass relative to 100 parts by mass of the base polymer contained in the adhesive composition. parts or less, preferably about 0.001 to 5 parts by mass, more preferably about 0.001 to 4 parts by mass, still more preferably about 0.001 to 3 parts by mass.

Alternatively, it may be an adhesive composition that does not contain the above-mentioned cross-linking agent. When a photocurable adhesive composition is used as the adhesive composition according to one embodiment of the present invention, the adhesive composition may be substantially free of cross-linking agents such as isocyanate-based cross-linking agents. Here, the adhesive composition does not substantially contain a cross-linking agent (typically, an isocyanate-based cross-linking agent) means that the amount of the cross-linking agent is less than 0.05 parts by mass (for example, less than 0.01 parts by mass) based on 100 parts by mass of the above-mentioned base polymer. share).

In order to make the cross-linking reaction proceed more efficiently, a cross-linking catalyst can be used. Examples of the cross-linking catalyst include metal-based cross-linking catalysts such as tetra-n-butyl titanate, tetraisopropyl titanate, iron triacetyl acetonate, butyl tin oxide, and dioctyl tin dilaurate. Among them, tin-based cross-linking catalysts such as dioctyltin dilaurate are preferred.

The amount of cross-linking catalyst used is not particularly limited. The usage amount of the cross-linking catalyst relative to 100 parts by mass of the base polymer in the adhesive composition can be, for example, about 0.0001 or more parts by mass and not more than 1 part by mass, or it can be about 0.001 or more parts by mass and not more than 0.1 parts by mass, or it can be about 0.005 parts by mass or more and 0.5 parts by mass or less.

If necessary, a multifunctional monomer can be used in the adhesive composition (or adhesive layer). Multifunctional monomers can help achieve the purpose of adjusting the cohesive force by replacing the above-mentioned cross-linking agent or being used in combination with the cross-linking agent. For example, in the adhesive layer formed from the photocurable adhesive composition, a polyfunctional monomer can be preferably used.

Examples of the polyfunctional monomer include ethylene glycol di(meth)acrylate, propylene glycol di(meth)acrylate, polyethylene glycol di(meth)acrylate, and polypropylene glycol di(meth)acrylate. Acrylate, neopentyl glycol di(meth)acrylate, pentaerythritol di(meth)acrylate, pentaerythritol tri(meth)acrylate, dipentaerythritol hexa(meth)acrylate, ethylene glycol di(meth)acrylate ) Acrylate, 1,6-hexanediol di(meth)acrylate, 1,12-dodecanediol di(meth)acrylate, trimethylolpropane tri(meth)acrylate, tetrakis Hydroxymethylmethane tri(meth)acrylate, allyl (meth)acrylate, vinyl (meth)acrylate, divinylbenzene, epoxy acrylate, polyester acrylate, urethane acrylate , butanediol (meth)acrylate, hexanediol di(meth)acrylate, etc.

Among them, trimethylolpropane tri(meth)acrylate, 1,6-hexanediol di(meth)acrylate, and dipentaerythritol hexa(meth)acrylate can be preferably used. The polyfunctional monomer can be used individually by 1 type or in combination of 2 or more types.

The usage amount of the polyfunctional monomer varies depending on its molecular weight, the number of functional groups, etc., but is usually in the range of about 0.01 to 3.0 parts by mass based on 100 parts by mass of the base polymer. In several aspects, the usage amount of the multifunctional monomer relative to 100 parts by mass of the base polymer can be, for example, 0.02 parts by mass or more, 0.1 parts by mass or more, 0.5 parts by mass or more, or It is 1.0 parts by mass or more or 2.0 parts by mass or more. By increasing the usage amount of the polyfunctional monomer, there is a tendency to obtain higher cohesive force.

On the other hand, from the viewpoint of avoiding a decrease in the adhesion between the adhesive layer and the adjacent layer due to an excessive increase in cohesion, the usage amount of the polyfunctional monomer relative to 100 parts by mass of the base polymer can be, for example, It may be 10 parts by mass or less, it may be 5.0 parts by mass or less, or it may be 3.0 parts by mass or less.

(Acrylic oligomer) The adhesive composition (or adhesive layer) according to one embodiment of the present invention can be used from the viewpoint of improving the cohesive force or improving the adhesion to the surface adjacent to the adhesive layer (for example, the surface of the base material, etc.). ) may contain acrylic oligomers.

As the acrylic oligomer, it is preferable to use a polymer having a Tg higher than that of the acrylic polymer.

The Tg of the acrylic oligomer is not particularly limited, but may be, for example, about 20°C or more and 300°C or less. The Tg may be, for example, about 30°C or higher, about 40°C or higher, about 60°C or higher, about 80°C or higher, or about 100°C or higher. When the Tg of the acrylic oligomer becomes high, the overall effect of improving the cohesion force tends to become higher.

In addition, from the viewpoint of the gripping properties of the base material or impact absorption, the Tg of the acrylic oligomer may be, for example, about 250°C or lower, about 200°C or lower, or about 180°C or lower. Below about 150℃. In addition, the Tg of the acrylic oligomer is a value calculated based on the Fox formula similarly to the Tg of the acrylic polymer corresponding to the composition of the above-mentioned monomer components.

The Mw of the acrylic oligomer is typically about 1,000 or more and less than about 30,000, preferably about 1,500 or more and less than about 10,000, and more preferably about 2,000 or more but less than about 5,000. When Mw is within the above range, the effect of improving cohesion or adhesion with an adjacent surface is likely to be better exhibited.

The Mw of the acrylic oligomer can be measured by gel permeation chromatography (GPC) and can be obtained as a standard polystyrene-converted value. Specifically, 2 TSKgelGMH-H (20) columns were used as columns in HPLC8020 manufactured by Tosoh Corporation, and the measurement was performed using a tetrahydrofuran solvent at a flow rate of approximately 0.5 mL/min.

Examples of the monomer components constituting the acrylic oligomer include: the above-mentioned C _1-20 alkyl (meth)acrylates; the above-mentioned alicyclic hydrocarbon group-containing (meth)acrylates; the above-mentioned various aromatic-containing (meth)acrylates. Hydrocarbyl (meth)acrylate; (meth)acrylate obtained from terpene derivative alcohol; and other (meth)acrylate monomers. These can be used individually by 1 type or in combination of 2 or more types.

From the viewpoint of improving adhesion, it is preferable that the acrylic oligomer contains (methyl) having a branched chain structure as an alkyl group such as isobutyl (meth)acrylate or tert-butyl (meth)acrylate. Acrylic monomers with larger structures, such as alkyl acrylate; (meth)acrylate containing alicyclic hydrocarbon groups or (meth)acrylate containing aromatic hydrocarbon groups, are used as monomer units.

In addition, when ultraviolet rays are used during the synthesis of acrylic oligomers or the production of adhesive layers, a monomer having a saturated hydrocarbon group at the ester terminal is preferable in that it is less likely to cause polymerization inhibition. For example, it is preferable to use Use a (meth)acrylic acid alkyl ester whose alkyl group has a branched chain structure or a (meth)acrylic acid ester containing a saturated alicyclic hydrocarbon group.

The proportion of the (meth)acrylate monomer in the total monomer components constituting the acrylic oligomer is typically more than 50% by weight, preferably more than 60% by weight, more preferably more than 70% by weight ( For example, 80% by weight or more, and further 90% by weight or more).

In a preferred aspect, the acrylic oligomer has a monomer composition substantially including only one or more than two (meth)acrylic acid ester monomers. When the monomer component contains alicyclic hydrocarbon group-containing (meth)acrylate and (meth)acrylic acid C _1-20 alkyl ester, the weight ratio is not particularly limited, for example, it can be 10/90 ~90/10 range, 20/80~80/20 range, 70/30~30/70 range, etc.

As the monomer component constituting the acrylic oligomer, in addition to the above-mentioned (meth)acrylate monomer, a functional group-containing monomer may also be used if necessary. Examples of functional group-containing monomers include: N-vinyl-2-pyrrolidone, N-acrylamide, and other heterocyclic monomers containing nitrogen atoms; (meth)acrylic acid N,N- Amino group-containing monomers such as dimethylaminoethyl ester; N,N-diethyl (meth)acrylamide and other amide group-containing monomers; AA (Acrylate Acid, acrylic acid), MAA (Methacrylic Acid, Carboxyl-containing monomers such as methacrylic acid); hydroxyl-containing monomers such as 2-hydroxyethyl (meth)acrylate. These functional group-containing monomers can be used alone or in combination of two or more.

When a functional group-containing monomer is used, the proportion of the functional group-containing monomer in the total monomer components constituting the acrylic oligomer may be, for example, 1% by weight or more, 2% by weight or more, or 3% by weight. % or more, and, for example, it may be 15% by weight or less, 10% by weight or less, or 7% by weight or less.

As preferred acrylic oligomers, for example, dicyclopentyl methacrylate (DCPMA), cyclohexyl methacrylate (CHMA), isopropyl methacrylate (IBXMA), isopropyl acrylate (IBXA), acrylic acid In addition to the homopolymers of dicyclopentyl ester (DCPA), 1-adamantyl methacrylate (ADMA), and 1-adamantyl acrylate (ADA), copolymers of DCPMA and MMA, and copolymers of DCPMA and IBXMA can also be cited. Copolymer of ADA and methyl methacrylate (MMA), copolymer of CHMA and isobutyl methacrylate (IBMA), copolymer of CHMA and IBXMA, copolymer of CHMA and acryloylmethacrylate (ACMO) material, copolymer of CHMA and diethyl acrylamide (DEAA), copolymer of CHMA and AA, etc.

The acrylic oligomer can be formed by polymerizing its constituent monomer components. The polymerization method or polymerization mode is not particularly limited, and various previously known polymerization methods (such as solution polymerization, emulsion polymerization, block polymerization, photopolymerization, radiation polymerization, etc.) can be used in an appropriate manner. The types of polymerization initiators (for example, azo polymerization initiators) that can be used if necessary are roughly as exemplified for the synthesis of acrylic polymers, and the polymerization initiator dosage or optional chain transfer agents (for example, mercaptans) The amount is appropriately set based on technical common sense so as to achieve a desired molecular weight, and therefore detailed description is omitted.

When the adhesive composition contains an acrylic oligomer, its content may be, for example, 0.01 parts by mass or more based on 100 parts by mass of the above-mentioned base polymer. From the perspective of obtaining higher effects, it may also be 0.05. It may be more than 0.1 parts by mass or more than 0.2 parts by mass.

In addition, from the viewpoint of compatibility with the base polymer, etc., the content of the acrylic oligomer is usually less than 50 parts by mass, preferably less than 30 parts by mass, and more preferably 25 parts by mass or less. It may be 10 parts by mass or less, 5 parts by mass or less, or 1 part by mass or less.

(other ingredients) The adhesive composition according to one embodiment of the present invention may optionally contain an adhesive imparting resin (for example, rosin-based, petroleum-based, terpene-based, phenolic-based, ketone-based, etc. adhesive-imparting resins) within the scope that does not impair the effects of the present invention. , viscosity adjusters (such as tackifiers), leveling agents, plasticizers, fillers, colorants such as pigments or dyes, stabilizers, preservatives, anti-aging agents and other common additives in the field of adhesive compositions as other optional ingredients. Regarding such various additives, conventionally known ones can be used by common methods, and are not particularly characteristic of the present invention, so detailed descriptions are omitted.

Furthermore, the technology of this embodiment can exhibit good adhesion without using the above-mentioned tackifier resin. Therefore, the content of the above-mentioned tackifier resin in the adhesive composition relative to 100 parts by mass of the base polymer can be, for example, It may be less than 10 parts by mass, and may be less than 5 parts by mass. The content of the above-mentioned adhesive imparting resin may be less than 1 part by mass (for example, less than 0.5 parts by mass), or less than 0.1 part by mass (more than 0 parts by mass and less than 0.1 part by mass). The above-mentioned adhesive composition may be Does not contain adhesive imparting resin.

In the adhesive composition according to one embodiment of the present invention, from the viewpoint of improving transparency, it is preferable that the amount of components other than the base polymer in the adhesive composition is limited. In the technology of this embodiment, the amount of components other than the base polymer in the adhesive composition is usually about 30% by weight or less, suitably about 15% by weight or less, and preferably about 12% by weight or less (for example, about 10% by weight). weight% or less). The amount of components other than the base polymer in the adhesive composition of one embodiment may be about 5% by weight or less, or about 3% by weight or less, or about 1.5% by weight or less (for example, about 1% by weight or less). ). A composition in which the amount of components other than the base polymer is limited can be preferably used for the adhesive composition of this embodiment.

＜Adhesive layer＞ The adhesive layer according to one embodiment of the present invention is formed from the above-mentioned adhesive composition. FIG. 2 is a schematic cross-sectional view showing a structural example of an adhesive layer according to an embodiment of the present invention.

The above-mentioned adhesive layer may be a hardened layer of an adhesive composition. That is, the adhesive layer can be formed by applying (for example, coating) the adhesive composition to an appropriate surface and then performing a hardening treatment as appropriate. When two or more hardening treatments (drying, cross-linking, polymerization, etc.) are performed, they can be performed simultaneously or in multiple stages.

In an adhesive composition using a partial polymer (polymer slurry) containing a monomer component, a final copolymerization reaction is typically performed as the above-mentioned hardening treatment. That is, part of the polymer is subjected to further copolymerization to form a complete polymer. For example, in the case of a photocurable adhesive composition, light irradiation is performed. If necessary, hardening treatments such as cross-linking and drying can be performed. For example, when the photocurable adhesive composition needs to be dried (for example, in the case of a photocurable adhesive composition in which part of the polymer of the monomer components is dissolved in an organic solvent), the composition is dried and then photocured. Just harden.

In an adhesive composition using a complete polymer, typically, as the above-mentioned hardening treatment, drying (heat drying), cross-linking, etc. are performed as necessary. In the case of a solvent-based adhesive composition that is provided with photocurability (photocrosslinkability) by adding a polyfunctional monomer, the composition may be dried and then photocured. Here, after drying the above composition, it means after pasting the following adhesive sheet obtained through the above drying to the adherend. The following adhesive sheet can be used in such a manner that it is attached to an adherend and then adhered to the adherend by a method including photocuring.

The adhesive layer of a multi-layer structure of more than two layers can be produced by laminating preformed adhesive layers. Alternatively, the adhesive composition may be coated on the preformed first adhesive layer, and the adhesive composition may be hardened to form the second adhesive layer. In the case where the adhesive layer of the adhesive sheet described below is used in the form of being attached to the adherend and then photocured, and has a multi-layer structure, the photo-hardened adhesive layer may be one of the above-mentioned multi-layer structures. It may include a part of the layer (for example, one layer) or all of the layers.

The adhesive composition can be coated using, for example, a gravure roll coater, a reverse roll coater, a contact roll coater, a dip roll coater, a rod coater, a blade coater, or a spray coating. It is implemented using a commonly used coating machine such as a machine. Among the following adhesive sheets in the form of a base material, as a method of providing an adhesive layer on the base material, a direct method of directly applying an adhesive composition to the base material to form an adhesive layer can be used, or a direct method of forming an adhesive layer can be used. A transfer method in which the adhesive layer formed on the peeling surface is transferred to the base material.

The thickness of the adhesive layer is not particularly limited, but may be about 3 μm to 2000 μm, for example. From the viewpoint of step followability and closeness to the adherend, in some embodiments, the thickness of the adhesive layer can be, for example, 5 μm or more, preferably 10 μm or more, and preferably 20 μm or more. More preferably, it is 30 μm or more. The thickness of the adhesive layer may be more than 50 μm, may be more than 50 μm, may be more than 70 μm, may be more than 100 μm, may be more than 120 μm.

Furthermore, from the viewpoint of preventing the occurrence of paste residue due to aggregation and destruction of the adhesive layer, in some aspects, the thickness of the adhesive layer may be, for example, 1000 μm or less, or 700 μm or less. It may be 500 μm or less, 300 μm or less, 200 μm or less, or 170 μm or less. The technology of this aspect can also be better implemented in the form of the following adhesive sheets where the thickness of the adhesive layer is 130 μm or less, 90 μm or less, or 60 μm or less (for example, 40 μm or less). Furthermore, in the following adhesive sheet having an adhesive layer having a multi-layer structure of more than two layers, the thickness of the adhesive layer refers to the thickness from the adhesive surface attached to the adherend to the side opposite to the adhesive surface. The thickness of the surface.

＜Adhesive sheet＞ An adhesive sheet according to an embodiment of the present invention has the above-mentioned adhesive layer. The adhesive sheet of this embodiment may be an adhesive sheet with a base material having an adhesive layer on one or both sides of a sheet-like base material (support), or the adhesive layer may be retained on a release sheet. Adhesive sheet without base material according to the shape of the material. The concept of adhesive sheet here may include adhesive tape, adhesive label, adhesive film, etc.

Furthermore, the adhesive layer is typically formed continuously, but is not limited to this form. For example, the adhesive layer may be formed in a regular or random pattern such as dots or strips. In addition, the adhesive sheet of this embodiment may be in the form of a roller or a single sheet. Alternatively, it may be an adhesive sheet further processed into various shapes.

(UV absorbing layer) The adhesive sheet according to one embodiment of the present invention may have a UV absorbing layer on one side of the adhesive layer. 3 is a schematic cross-sectional view showing a structural example of a UV absorbing layer provided on one side of the adhesive layer in the adhesive sheet according to one embodiment of the present invention. The adhesive sheet 1 shown in FIG. 3 includes an adhesive layer 21 and a UV absorbing layer 31 provided on one side of the adhesive layer. The UV absorbing layer 31 contains a UV absorber such as a UV absorbing polymer.

Depending on the type of photoacidifier or photobase generator contained in the adhesive sheet, there is a possibility that ultraviolet rays contained in sunlight may generate acid or alkali, causing discoloration or coloring of the sheet. In this case, there is a problem that it is difficult to change or color the adhesive sheet at any time by irradiating active energy rays. In order to prevent this problem, it is preferable to provide the above-mentioned UV absorbing layer as a measure against external light.

That is, by providing the UV absorbing layer on the side of the adhesive layer that is exposed to sunlight, ultraviolet rays contained in sunlight can be prevented from reaching the adhesive layer. As a result, discoloration of the adhesive layer caused by sunlight can be prevented. or coloring. Furthermore, even when a UV absorbing layer is provided, the adhesive sheet can be discolored or colored by selecting active energy rays that are not absorbed by the UV absorbing layer and irradiating them at an appropriate time.

Furthermore, when the UV absorbing layer is laminated on the adhesive layer and is discolored or colored by irradiation with active energy rays, it is preferable that the photoacid generator and the photobase generator become active and the energy is absorbed by the UV absorbing layer. In order to prevent ultraviolet rays, which are active energy rays, from being absorbed by the UV absorbing layer, active energy rays are irradiated from the side opposite to the surface where the UV absorbing layer is provided in the self-adhesive sheet.

The UV-absorbing polymer used as a UV absorber may preferably be selected from polymers containing structural units with UV-absorbing capabilities. Examples include 2-hydroxy-4-methoxybenzophenone, 2-hydroxy-4-octoxybenzophenone, and 2-hydroxy-4-dodecyloxybenzophenone. , 2-hydroxy-4-methoxy-5-sulfobenzophenone, 2,4-dihydroxybenzophenone, 2,2'-dihydroxy-4,4'-dimethoxydiphenyl Methone, bis(2-methoxy-4-hydroxy-5-benzylphenyl)methane, 2-hydroxy-4-propenyloxybenzophenone, 2-hydroxy-4-methacrylene hydroxybenzophenone, 2-hydroxy-4-(2-propenyloxy)ethoxybenzophenone, 2-hydroxy-4-(2-methacrylyloxy)ethoxydi 2-hydroxybenzophenone derivatives such as benzophenone and 2-hydroxy-4-(2-methyl-2-propenyloxy)ethoxybenzophenone; including 2-(2'-hydroxyl -5'-methylphenyl)benzotriazole, 2-(2'-hydroxy-5'-tert-butylphenyl)benzotriazole, 2-(2'-hydroxy-5'-3' ,5'-di-tert-butylphenyl)benzotriazole, 2-(2'-hydroxy-3'-tert-butyl-5'-methylphenyl)-5-chlorobenzotriazole, 2-(2'-Hydroxy-3'-5'-di-3-pentylphenyl)benzotriazole, 2-{2'-hydroxy-3'-(3'',4'',5'' ,6''-tetrahydrophthalimidemethyl-5'-methylphenyl}benzotriazole, 2,2-methylenebis{4-(1,1,3,3- Tetramethylbutyl)-6-(2H-benzotriazol-2-yl)phenol}, 2-{2'-hydroxy-5'-(methacrylyloxy)phenyl}benzotriazole , 2-[2'-hydroxy-5'-(acryloxy)phenyl]benzotriazole, 2-[2'-hydroxy-3'-tert-butyl-5'-(methacryloxy) Oxy)phenyl]benzotriazole, 2-[2'-hydroxy-3'-methyl-5'-(acrylyloxy)phenyl]benzotriazole, 2-{2'-hydroxy- 5'-(methacryloxypropyl)phenyl}-5-chlorobenzotriazole, 2-[2'-hydroxy-5'-(methacryloxyethyl)phenyl]benzene Triazole, 2-[2'-hydroxy-5'-(acryloxyethyl)phenyl]benzotriazole, 2-[2'-hydroxy-3'-tert-butyl-5'- (methacryloxyethyl)phenyl]benzotriazole, 2-[2'-hydroxy-3'-methyl-5'-(acryloxyethyl)phenyl]benzotriazole , 2-[2'-hydroxy-5'-(methacryloxypropyl)phenyl]-5-chlorobenzotriazole, 2-[2'-hydroxy-5'-(methacryloxypropyl) Butyl)phenyl]-5-methylbenzotriazole, [2-hydroxy-3-tert-butyl-5-(acrylyloxyethoxycarbonylethyl)phenyl]benzotriazole, etc. 2-hydroxybenzotriazole derivatives; salicylic acid derivatives such as phenyl salicylate, p-tert-butylphenyl salicylate, p-octylphenyl salicylate, but are not limited to these .

The UV-absorbing polymer preferably has a maximum absorption wavelength in the range of 300 to 400 nm.

The UV-absorbing polymer is preferably a copolymer that is a reaction product of a mixture of a UV-absorbing vinyl monomer and one or more copolymerizable vinyl monomers. Here, the UV-absorbing vinyl monomer includes those having the above-mentioned properties. Structural unit of UV absorption ability.

Examples of copolymerizable vinyl monomers include acrylic acid, alkyl acrylic acid (methacrylic acid, etc.), esters derived from acrylic acid, or amides (eg, acrylamide, methacrylamide, n-butylacrylamide). , tert-butylacrylamide, diacetone acrylamide, methyl acrylate, ethyl acrylate, n-propyl acrylate, n-butyl acrylate, tert-butyl acrylate, isobutyl acrylate, 2-ethylhexyl acrylate Ester, n-octyl acrylate, lauryl acrylate, 2-ethoxyethyl acrylate, 2-methoxyethyl acrylate, methyl methacrylate, ethyl methacrylate, n-butyl methacrylate, methyl b-hydroxyacrylate, etc.), vinyl esters (such as vinyl acetate, vinyl propionate, vinyl laurate, etc.), acrylonitrile, methacrylonitrile, aromatic vinyl compounds (such as styrene and its derivatives, For example, vinyltoluene, divinylbenzene, vinylacetophenone, sulfostyrene, etc.), itaconic acid, methylmaleic acid, crotonic acid, vinylidene chloride, vinyl alkyl ether ( For example, vinyl ether, etc.), esters of maleic acid, N-vinyl-2-pyrrolidone, N-vinylpyridine, 2- or 4-vinylpyridine, etc., sulfonic acids containing monomers (such as Acrylamide-2,2'-dimethylpropanesulfonic acid, 2-sulfoethyl methacrylate, 3-sulfopropyl methacrylate, etc.).

Among these monomers, preferred are acrylic acid esters, methacrylic acid esters and aromatic vinyl compounds.

Specific examples of preferred monomers include: butyl acrylate; 2-ethylhexyl acrylate; 2-ethoxyethyl acrylate; 2-methoxyethyl acrylate; acrylic acid; methacrylic acid; acrylic acid. Amine; 2-hydroxyethyl acrylate; vinyl acetate; styrene; N-vinyl-2-pyrrolidinone; 2-sulfoethyl methacrylate and its metal salts; 2-acrylamide-2-methyl Propanesulfonic acid and its metal salts.

(Adhesive layer containing UV absorber) The adhesive sheet according to one embodiment of the present invention may be provided with an adhesive layer containing a UV absorber on one side of the adhesive layer (hereinafter, also referred to as "UV absorber-containing adhesive layer" or "UV absorbent"). "Adhesive layer") shape. 4 is a schematic cross-sectional view showing a structural example of an adhesive sheet containing a UV absorber on one side of the adhesive layer in an adhesive sheet according to an embodiment of the present invention. The adhesive sheet 2 shown in FIG. 4 includes an adhesive layer 21 and an adhesive layer 41 containing a UV absorber provided on one side of the adhesive layer 21 . Thereby, the same light countermeasures as the above-mentioned UV absorbing layer can be achieved.

The UV absorber contained in the adhesive layer 41 can be the same as the above-mentioned UV absorber. In addition, the UV absorber-containing adhesive layer 41 may contain the same components as the adhesive layer of the above-mentioned embodiment of the present invention.

(Substrate) The adhesive sheet in some embodiments may be in the form of an adhesive sheet with a base material bonded to the other back surface of the adhesive layer. FIG. 5 is a schematic cross-sectional view showing an example of a structure in which an adhesive layer is formed on one side of the base material in the adhesive sheet according to one embodiment of the present invention. The adhesive sheet 3 shown in FIG. 5 includes a base material 51 and an adhesive layer 21 formed on one side of the base material.

again. As an adhesive sheet according to another embodiment, FIG. 6 shows a schematic cross-sectional view of a configuration example in which an adhesive layer is formed on both sides of the base material 51 . The adhesive sheet 4 shown in FIG. 6 includes a base material 51, and a first adhesive layer 21 and a second adhesive layer 22 formed on both sides of the base material.

The material of the base material is not particularly limited and can be appropriately selected according to the purpose of use or usage pattern of the adhesive sheet. Non-limiting examples of substrates that can be used include: polyolefin films containing polyolefins such as polypropylene and ethylene-propylene copolymer as the main component; films containing polyethylene terephthalate or polyterephthalate; Polyester film with polyester as the main component such as butylene formate, polyvinyl chloride film with polyvinyl chloride as the main component and other plastic films; including polyurethane foam, polyethylene foam, polychloride Foam sheets of butadiene foam and other foams; various fibrous materials (can be natural fibers such as linen and cotton, synthetic fibers such as polyester and vinylon, semi-synthetic fibers such as acetate, etc.) individually Woven and non-woven fabrics formed or formed by blending; Japanese paper, Dowling paper, kraft paper, crepe paper and other papers; aluminum foil, copper foil and other metal foils; etc. It may also be a base material composed of a composite of these. Examples of the base material of such a composite structure include a base material of a structure in which a metal foil and the above-mentioned plastic film are laminated, a plastic sheet reinforced with inorganic fibers such as glass cloth, and the like.

As the base material of the adhesive sheet according to one embodiment of the present invention, various films (hereinafter also referred to as support films) can be suitably used. The above-mentioned support film may be a porous film such as a foam film or a non-woven sheet, or may be a non-porous film, or may be a film having a structure in which a porous layer and a non-porous layer are laminated. .

In some aspects, as the above-mentioned support film, one containing a resin film that can independently maintain its shape (self-supporting or independent) as a base film can be preferably used. The "resin film" here refers to a non-porous structure, typically a resin film that does not contain substantially bubbles (no voids). Therefore, the above-mentioned resin film is different from the concept of foam film or non-woven fabric. The above-mentioned resin film may have a single-layer structure, or may have a multi-layer structure of two or more layers (for example, a three-layer structure).

As the resin material constituting the resin film, for example, polyester, polyolefin, polycycloolefin derived from a monomer having an aliphatic ring structure such as a norphene structure, nylon 6, nylon 66, and partially aromatic polyamide Such as polyamide (PA), polyimide (PI), polyamide imide (PAI), polyether ether ketone (PEEK), polyether sulfide (PES), polyphenylene sulfide (PPS), polyamide Carbonate (PC), polyurethane (PU), ethylene-vinyl acetate copolymer (EVA), polystyrene, polyvinyl chloride, polyvinylidene chloride, polytetrafluoroethylene (PTFE) and other fluorine Resins, acrylic resins such as polymethyl methacrylate, cellulose polymers such as diacetyl cellulose or triacetyl cellulose, vinyl butyraldehyde polymers, aryl ester polymers, polyoxymethylene polymers, Resins such as epoxy polymers.

The resin film may be formed using a resin material containing one type of resin alone, or may be formed using a blend of two or more resin materials. The above-mentioned resin film may not be stretched, or may be stretched (eg, uniaxially stretched or biaxially stretched).

Preferable examples of the resin material constituting the resin film include polyester resin, PPS resin and polyolefin resin. Here, the polyester-based resin refers to a resin containing polyester in a ratio exceeding 50% by weight. Similarly, PPS resin refers to a resin containing PPS in a ratio exceeding 50% by weight, and polyolefin-based resin refers to a resin containing polyolefin in a ratio exceeding 50% by weight.

As the polyester-based resin, a polyester-based resin containing as a main component polyester obtained by polycondensing a dicarboxylic acid and a diol is typically used. Specific examples of polyester-based resins include polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polyethylene naphthalate (PEN), and polynaphthalene dicarboxylate. Butylene formate, etc.

As the polyolefin resin, one type of polyolefin can be used alone or two or more types of polyolefin can be used in combination. The polyolefin may be, for example, a homopolymer of α-olefin, a copolymer of two or more α-olefins, a copolymer of one or more α-olefins and other vinyl monomers, etc.

Specific examples include ethylene-propylene copolymers such as polyethylene (PE), polypropylene (PP), poly-1-butene, poly-4-methyl-1-pentene, and ethylene-propylene rubber (EPR). , ethylene-propylene-butylene copolymer, ethylene-butylene copolymer, ethylene-vinyl alcohol copolymer, ethylene-ethyl acrylate copolymer, etc. Either low density (LD) polyolefin or high density (HD) polyolefin can be used.

Examples of polyolefin resin films include non-stretched polypropylene (CPP) film, biaxially stretched polypropylene (OPP) film, low-density polyethylene (LDPE) film, and linear low-density polyethylene (LLDPE) film. , medium density polyethylene (MDPE) film, high density polyethylene (HDPE) film, polyethylene (PE) film blended with two or more polyethylene (PE), blended polypropylene (PP) and polyethylene (PE) ) PP/PE blended film, etc.

Specific examples of resin films that can be preferably used as base materials include PET films, PEN films, PPS films, PEEK films, CPP films, and OPP films. Preferable examples in terms of strength include PET film, PEN film, PPS film and PEEK film. From the viewpoints of ease of acquisition, dimensional stability, optical properties, etc., a PET film is a preferable example.

If necessary, well-known additives such as light stabilizers, antioxidants, antistatic agents, colorants (dyes, pigments, etc.), fillers, slip agents, and anti-adhesive agents can be blended into the resin film. The compounding amount of the additive is not particularly limited and can be appropriately set according to the use of the adhesive sheet.

The manufacturing method of the resin film is not particularly limited. For example, conventionally known general resin film forming methods such as extrusion molding, inflation molding, T-die die casting, and calender roll molding can be suitably used.

The above-mentioned base material may substantially include such a resin film. Alternatively, the base material may also include an auxiliary layer in addition to the resin film. Examples of the above-mentioned auxiliary layers include: an optical property adjustment layer (such as an anti-reflection layer), a printing layer or a laminated layer for imparting a desired appearance to the base material or adhesive sheet, an antistatic layer, and a base layer. Surface treatment layers such as coatings and peeling layers. Moreover, the said base material may be the following optical member.

The thickness of the base material is not particularly limited and can be selected according to the purpose of use or usage pattern of the adhesive sheet. The thickness of the substrate may be, for example, 1000 μm or less, 500 μm or less, 100 μm or less, 70 μm or less, 50 μm or less, 25 μm or less, or 10 μm or less. μm or less, and may be 5 μm or less. If the thickness of the base material becomes thinner, the flexibility of the adhesive sheet and its ability to follow the surface shape of the adherend tend to increase.

In addition, from the viewpoint of operability, processability, etc., the thickness of the base material may be, for example, 2 μm or more, may be more than 5 μm, or may be more than 10 μm. In several aspects, the thickness of the substrate may be, for example, 20 μm or more, 35 μm or more, or 55 μm or more.

If necessary, corona discharge treatment, plasma treatment, ultraviolet irradiation treatment, acid treatment, alkali treatment, primer coating, antistatic treatment, etc. can be performed on the side of the base material that is bonded to the adhesive layer. Previously known surface treatments. This kind of surface treatment can be used to improve the adhesion between the substrate and the adhesive layer, in other words, the adhesive layer's grip on the substrate. The composition of the primer is not particularly limited and can be appropriately selected from known ones. The thickness of the primer layer is not particularly limited, but is usually about 0.01 μm to 1 μm, preferably about 0.1 μm to 1 μm.

If necessary, the surface of the base material opposite to the side bonded to the adhesive layer (hereinafter also referred to as the back surface) may be subjected to previously known surface treatments such as peeling treatment, adhesiveness or adhesion improvement treatment, and antistatic treatment. For example, by surface-treating the back side of the base material with a release treatment agent, the unwinding force of the adhesive sheet wound into a drum shape can be reduced. As the release agent, polysiloxane release agents, long-chain alkyl release agents, olefin release agents, fluorine release agents, fatty amide release agents, molybdenum sulfide, and dioxide can be used. Silicon powder, etc.

(release liner) In the adhesive sheet of this embodiment, the adhesive layer or the adhesive layer containing the UV absorber can be protected by a release liner (release film, release film) until use.

As the release liner, conventional release paper can be used without particular limitation. For example, a base material having a release treatment layer, a low-adhesion base material containing a fluorine-based polymer, or a low-adhesion base material containing a non-polar polymer can be used. Substrate etc.

Examples of the base material having a release treatment layer include plastic films or papers surface-treated with release treatment agents such as polysiloxane-based, long-chain alkyl-based, fluorine-based, and molybdenum sulfide.

Examples of the fluorine-based polymer containing the low-adhesion base material include polytetrafluoroethylene, polychlorotrifluoroethylene, polyvinyl fluoride, polyvinylidene fluoride, and tetrafluoroethylene-hexafluoropropylene. copolymer, chlorofluoroethylene-vinylidene fluoride copolymer, etc.

Examples of the nonpolar polymer of the low-adhesion base material including the nonpolar polymer include olefin-based resins (eg, polyethylene, polypropylene, etc.). Furthermore, the release liner can be formed by a known or conventional method. In addition, the thickness of the release liner is not particularly limited.

In the technology of this embodiment, the haze value of the adhesive sheet is preferably about 10% or less, and may be about 5% or less (for example, about 3% or less). The above-mentioned haze value is preferably 1.0% or less. An adhesive sheet with such a high transparency is preferable in that the appearance of the adhesive sheet changes significantly when discolored or colored in the present invention. The haze value of the adhesive sheet may be less than 1.0%, less than 0.7%, or less than 0.5% (for example, 0-0.5%). The haze value of the adhesive sheet can also be preferably applied to the haze value of the adhesive layer in the technology of this embodiment.

The "haze value" here refers to the ratio of diffusely transmitted light to total transmitted light when the measurement object is irradiated with visible light. Also called Haze. The haze value can be expressed by the following formula. Th[%]＝Td/Tt×100

In the above formula, Th is the haze value [%], Td is the scattered light transmittance, and Tt is the total light transmittance. The haze value can be measured according to the method described in the following examples. The haze value can be adjusted, for example, by selecting the composition or thickness of the adhesive layer.

The technology of this embodiment can be suitably used for electronic components, optical components, building components, etc., for example. [Example]

Hereinafter, embodiments of the present invention will be described in more detail using examples.

[Preparation of adhesive composition] (Adhesive composition A1) In a reaction vessel equipped with a condenser tube, a nitrogen introduction tube, a thermometer and a stirring device, add 95 parts by weight of n-butyl acrylate (BA) as the monomer component, 5 parts by weight of acrylic acid (AA), and ethyl acetate as the polymerization solvent. 122 parts by weight, add 0.2 parts by weight of 2,2'-azobisisobutyronitrile (AIBN) as a thermal polymerization initiator, and perform solution polymerization in a nitrogen environment to obtain an acrylic polymer with an Mw of 600,000. Solution of substance 1.

To the solution obtained above, 1 part by weight of 6-(diethylamino)-2-[(3-trifluoromethyl)aniline as a leuco pigment was added per 100 parts by weight of the above-mentioned polymer component. base] 𠮿 -9-Spiro-3'-phthalide, 0.1 part by weight of a 50% propylene carbonate solution containing triarylsonium hexafluorophosphate as the main component as a photoacid generator (trade name: CPI-100P , manufactured by San-Apro Co., Ltd.), 0.05 parts by weight of epoxy cross-linking agent (1,3-bis(N,N-diglycidylaminomethyl)cyclohexane based on solid content, commercial product Name: Tetrad C, manufactured by Mitsubishi Gas Chemical Co., Ltd.) and uniformly mixed to prepare adhesive composition A1.

(Adhesive composition A2) Adhesive composition A2 was prepared in the same manner as the preparation of adhesive composition A1, except that the usage amount of the photoacid generator was set to 1 part by weight per 100 parts by weight of the above-mentioned polymer component.

(Adhesive composition A3) Adhesive composition A3 was prepared in the same manner as the preparation of adhesive composition A1, except that the usage amount of the photoacid generator was set to 5 parts by weight per 100 parts by weight of the above-mentioned polymer component.

(Adhesive composition A4) Adhesive composition A4 was prepared in the same manner as the preparation of adhesive composition A1, except that the usage amount of the photoacid generator was set to 10 parts by weight per 100 parts by weight of the above-mentioned polymer component.

(Adhesive composition A5) In addition to setting the usage amount of the leuco pigment to 10 parts by weight per 100 parts by weight of the above-mentioned polymer component and setting the usage amount of the photoacid generator to 20 parts by weight, the preparation of the adhesive composition A1 In the same manner, prepare adhesive composition A5.

(Adhesive composition A6) Except that the type of photoacid generator was triphenylsulfonium-nonafluorobutane-1-sulfonate (trade name: ADEKA ARKLS SP-056, manufactured by ADEKA Corporation) and the usage amount was 1 part by weight. , prepare adhesive composition A6 in the same manner as the preparation of adhesive composition A1.

(Adhesive composition A7) The adhesive composition A7 was prepared in the same manner as the adhesive composition A6 except that the usage amount of the photoacid generator was set to 5 parts by weight.

(Adhesive composition A8) Adhesive composition A8 was prepared in the same manner as adhesive composition A1 except that no photoacid generator was used.

(Adhesive composition A9) Adhesive composition A9 was prepared in the same manner as adhesive composition A2, except that no leuco pigment was used.

＜Preparation of adhesive sheet＞ (Example 1) The adhesive composition A1 was applied to a 38 μm-thick release film R1 (Mitsubishi Plastics Co., Ltd., MRF#38) that became the peeling surface on one side of the polyester film, and dried at 135°C for 2 minutes to form a 50 μm-thick release film. Adhesive layer B1. A peeling film R2 (Mitsubishi Plastics Co., Ltd., MRE#38) with a thickness of 38 μm was laminated on one side of the polyester film to become the peeling surface of the adhesive layer B1, thereby obtaining a film R2 and an adhesive layer laminated in sequence. The adhesive sheet of Example 1 of B1 and release film R1.

(Example 2) The adhesive sheet of Example 2 was produced in the same manner as Example 1 except that adhesive composition A2 was used instead of adhesive composition A1.

(Example 3) The adhesive sheet of Example 3 was produced in the same manner as Example 1 except that adhesive composition A3 was used instead of adhesive composition A1.

(Example 4) The adhesive sheet of Example 4 was produced in the same manner as in Example 1, except that adhesive composition A4 was used instead of adhesive composition A1.

(Example 5) The adhesive sheet of Example 5 was produced in the same manner as Example 1 except that adhesive composition A5 was used instead of adhesive composition A1.

(Example 6) The adhesive sheet of Example 6 was produced in the same manner as Example 1 except that adhesive composition A6 was used instead of adhesive composition A1. (Example 7) The adhesive sheet of Example 7 was produced in the same manner as Example 1 except that adhesive composition A7 was used instead of adhesive composition A1.

(Example 8) The release film R2 of the adhesive sheet produced in Example 2 was peeled off, and an adhesive tape with UV absorption capacity (Nitto Denko Co., Ltd., product name: CS9934U) with a thickness of 100 μm was attached to produce Example 8 with a UV absorption layer. Adhesive sheet.

(Comparative example 1) The adhesive sheet of Comparative Example 1 was produced in the same manner as Example 1 except that adhesive composition A8 was used instead of adhesive composition A1.

(Comparative example 2) The adhesive sheet of Comparative Example 2 was produced in the same manner as Example 1 except that adhesive composition A9 was used instead of adhesive composition A1.

＜Measurement of Adhesion＞ (Adhesion before UV irradiation) The adhesive force before UV irradiation (initial) was measured for each of the adhesive sheets of Examples 1 to 7 and Comparative Examples 1 to 2 produced above. The measurement of adhesion is carried out according to the following sequence. First, each adhesive sheet was cut into a width of 20 mm and a length of 10 cm, and the release film was peeled off. Then, the adhesive sheet of each example was attached to the blue plate glass with a thickness of 1.2 mm using two reciprocating pressure-bonding rollers of 2 kg. Using a tensile testing machine (AUTOGRAPH AGS-X, manufactured by Shimadzu Corporation), peeling was performed at a peeling angle of 180 degrees and a peeling speed of 300 mm/min, and the force at this time was measured as the adhesive force (N/20 mm). The results are shown in Table 1.

(Adhesion after UV irradiation) The adhesive strength after UV irradiation (after triggering) was measured for each of the adhesive sheets of Examples 1 to 7 and Comparative Examples 1 to 2. The adhesive force after UV irradiation was measured by the same operation as above, except that the adhesive sheet was pressed onto a blue plate glass with a thickness of 1.2 mm and then irradiated with UV (wavelength range: 200~400 nm). UV irradiation is carried out through the above-mentioned alkali glass plate in an environment of 23°C and 50% RH. More specifically, by using a high-pressure mercury lamp (300 mW/cm ² ) to irradiate ultraviolet rays with a cumulative light intensity of 2000 mJ/cm ² , the 6-(diethylamino)-2 contained in the adhesive sheet in each example was -[(3-Trifluoromethyl)anilino]𠮿 -9-Spiro-3'-phthalide reacts with triarylsulfonium PF6 salt. The results are shown in Table 1.

＜Optical Characteristics Test＞ In this test, the coloring of the adhesive sheet caused by UV irradiation was evaluated by the change in transmittance before and after coloring. Using a spectrophotometer U4100 manufactured by Hitachi High-Technologies, each adhesive sheet of Examples 1 to 7 and Comparative Examples 1 to 2 was bonded to a blue plate glass with a thickness of 1.2 mm, and 380 to 780 was measured at a pitch of 5 nm. Total light transmittance at nm. This measurement is performed before and after UV treatment (UV wavelength range: 200 to 400 nm), and the value at which the change in transmittance before and after UV treatment reaches the maximum is determined, which is the "change in transmittance (%)". The results are shown in Table 1. ＜Weather resistance test＞ In this test, the weather resistance to light equivalent to ultraviolet light in external light, which is affected by the presence or absence of a UV absorbing layer, is evaluated. Using the Super Xenon Weather Meter SX75 manufactured by Suga Test Instruments, the adhesive sheets obtained in Example 2 and Example 8 were bonded to blue plate glass with a thickness of 1.2 mm, and a Super Xenon lamp was used. The irradiation output is 120 W, 300-400 nm light (equivalent to ultraviolet rays in external light) for 1 hour. Furthermore, in Example 8 having a UV absorbing layer, light was irradiated from the UV absorbing layer side. Thereafter, the "change in transmittance (%)" was measured in the same manner as above, and the results are shown in Table 2.

[Table 1] Table 1 Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 Example 7 Comparative example 1 Comparative example 2 Adhesive composition A1 A2 A3 A4 A5 A6 A7 A8 A9 Base polymer (parts by weight) Acrylic polymer 1 100 100 100 100 100 100 100 100 100 Leucic pigment (part by weight) 6-(diethylamino)-2-[(3-trifluoromethyl)anilino]𠮿 -9-spiro-3'-phthalide 1 1 1 1 10 1 1 1 0 photoacid generator CPI-100P 0.1 1 5 10 20 0 0 0 1 (parts by weight) SP-056 0 0 0 0 0 1 5 0 0 Epoxy cross-linking agent (parts by weight) Tetrad C 0.05 0.05 0.05 0.05 0.05 0.05 0.05 0.05 0.05 Presence or absence of UV absorbing layer without without without without without without without without without Change in transmittance (%) 5 48 92 95 99 33 66 1 1 Adhesion before UV irradiation (N) 10 10 10 10 10.5 10 10 9 9 Adhesion after UV irradiation (N) 10 10 10 10 10.5 10 10 9 9

[Table 2] Table 2 Example 2 Example 8 Adhesive composition A2 A2 Base polymer (parts by weight) Acrylic polymer 1 100 100 Leucic pigment (part by weight) 6-(diethylamino)-2-[(3-trifluoromethyl)anilino]𠮿 -9-spiro-3'-phthalide 1 1 Photoacid generator (parts by weight) CPI-100P 1 1 SP-056 0 0 Epoxy cross-linking agent (parts by weight) Tetrad C 0.05 0.05 Presence or absence of UV absorbing layer without have Change in transmittance after 1 hour of SXe irradiation (%) 57 2

The adhesive sheets of Examples 1 to 7 containing leuco pigments and photoacid generators cause transmittance changes by UV irradiation. Therefore, the adhesive sheet of the present invention containing a leuco pigment and a photoacid generator can change or be colored at any time by irradiation with active energy rays. On the other hand, the adhesive sheets of Comparative Examples 1 and 2 that do not contain leuco pigments or photoacid generators have almost no change in transmittance due to UV irradiation. Furthermore, none of the adhesive sheets of Examples 1 to 7 and Comparative Examples 1 and 2 had any change in adhesive force due to UV irradiation.

In addition, the change in transmittance of the adhesive sheet of Example 8 which has a UV absorbing layer on the adhesive layer containing a leuco pigment and a photoacid generator is compared with the adhesive sheet of Example 2 which does not have a UV absorbing layer. can be suppressed and weather resistance improved.

The preferred embodiments of the present invention have been described above. The present invention is not limited to the above-described embodiments. Various changes and substitutions can be made to the above-described embodiments without departing from the scope of the present invention. Furthermore, this application is based on a Japanese patent application filed on March 15, 2019 (Japanese Patent Application No. 2019-048841) and a Japanese patent application filed on March 9, 2020 (Japanese Patent Application No. 2020). -039643), the contents of which are incorporated into this application by reference.

1,2,3,4: Adhesive sheet 21,22: Adhesive layer 31:UV absorbing layer 41: Adhesive layer containing UV absorber 51:Substrate

FIG. 1 is a diagram showing an example of the oxidation-reduction reaction of the leuco pigment in the embodiment of the present invention. FIG. 2 is an example of a schematic cross-sectional view of the adhesive layer according to the embodiment of the present invention. FIG. 3 is an example of a schematic cross-sectional view of the adhesive sheet according to the embodiment of the present invention. FIG. 4 is an example of a schematic cross-sectional view of the adhesive sheet according to the embodiment of the present invention. FIG. 5 is an example of a schematic cross-sectional view of the adhesive sheet according to the embodiment of the present invention. FIG. 6 is an example of a schematic cross-sectional view of the adhesive sheet according to the embodiment of the present invention.

21: Adhesive layer

Claims (15)

An adhesive composition, which contains a base polymer, a leuco pigment, a photoacid generator and a cross-linking agent. The above leuco pigment is at least one pigment selected from the group consisting of a phthalide dye and a fluorescent yellow parent dye. , and the above-mentioned photoacid generator is selected from the group consisting of sulfonium salt-based compounds, iodonium salt-based compounds, aromatic N-oxycarboxylimine sulfonates, sulfonate ester compounds, and halomethyl-substituted mesitylene sulfonates.

At least one compound in the group of derivatives. The adhesive composition of claim 1, wherein the absorption wavelength of the leuco pigment changes according to the pH value. The adhesive composition of claim 1 or 2 contains 0.1 to 30 parts by mass of the above-mentioned leuco pigment per 100 parts by mass of the above-mentioned base polymer. The adhesive composition of claim 1 or 2 contains 0.1 to 30 parts by mass of the above-mentioned photoacid generator per 100 parts by mass of the above-mentioned base polymer. The adhesive composition of claim 1 or 2, wherein the base polymer contains an acrylic polymer. Such as the adhesive composition of claim 1 or 2, which changes color by irradiation with active energy rays. The adhesive composition of claim 1 or 2 is colored by irradiation with active energy rays. An adhesive layer comprising the adhesive composition of claim 1. An adhesive layer, which includes an adhesive composition containing a base polymer, a leuco pigment, a photoacid generator and a cross-linking agent, and the adhesive force does not change when irradiated by active energy rays. The above-mentioned leuco pigment is selected from At least one pigment from the group consisting of free phthalide dyes and fluorescent yellow matrix dyes, and the above-mentioned photoacid generator is selected from the group consisting of sulfonium salt compounds, iodonium salt compounds, and aromatic N-oxycarboxylimine sulfonic acid. Esters, sulfonate compounds and halomethyl substituted mesitylene

At least one compound in the group of derivatives. An adhesive sheet having an adhesive layer as claimed in claim 8 or 9. The adhesive sheet of claim 10, wherein a UV absorbing layer is provided on one side of the adhesive layer. The adhesive sheet of claim 11, wherein the UV absorbing layer is an adhesive layer containing a UV absorber. An adhesive sheet, which has an adhesive layer including an adhesive composition containing a base polymer, a leuco pigment, a photoacid generator and a cross-linking agent, and has a UV absorbing layer on one side of the adhesive layer, the above-mentioned The leuco pigment is at least one pigment selected from the group consisting of phthalide dyes and fluorescent yellow parent dyes, and the above-mentioned photoacid generator is selected from the group consisting of sulfur salt compounds, iodonium salt compounds, and aromatic N-oxyl chelates. Imine sulfonate ester, sulfonate ester compound and halomethyl substituted mesitylene

At least one compound in the group consisting of derivatives, and the above-mentioned UV absorbing layer is an adhesive layer containing a UV absorbing agent. The adhesive sheet of claim 10, wherein the adhesive layer is formed on the base material. The adhesive sheet of claim 13, wherein the adhesive layer is formed on the base material.