CN113993964A

CN113993964A - Pressure-sensitive adhesive composition and surface protective film

Info

Publication number: CN113993964A
Application number: CN201980097539.4A
Authority: CN
Inventors: 大地尉夫
Original assignee: DIC Corp
Current assignee: DIC Corp
Priority date: 2019-07-10
Filing date: 2019-07-10
Publication date: 2022-01-28
Anticipated expiration: 2039-07-10
Also published as: JP2022508414A; CN113993964B; JP7060165B2; WO2021003695A1

Abstract

Provided is a pressure-sensitive adhesive composition which suppresses contamination of an adherend to which a surface protective film has been applied even when the adherend is stored in a high-temperature, high-humidity environment. The pressure-sensitive adhesive composition comprises an acrylic resin (A), a curing agent (B) and a fluorine-containing additive (C). The curing agent (B) includes a polyfunctional isocyanate compound. The acrylic resin (a) is a hydroxyl group-containing acrylic resin. The content of the polyfunctional isocyanate compound is 1 part by mass or more per 100 parts by mass of the acrylic resin (a). The content of the fluorine-containing additive (C) is 0.01 to 6 parts by mass with respect to 100 parts by mass of the acrylic resin (A).

Description

Pressure-sensitive adhesive composition and surface protective film

Technical Field

The present invention relates to a pressure-sensitive adhesive composition and a surface protective film.

Background

Surface protective films are used to protect the surfaces of various components from dirt and scratches. For example, in the process of manufacturing a display device, a surface protective film is applied to an optical member or the like, and at a stage where surface protection is no longer required, it is peeled off from the optical member or the like.

As a pressure-sensitive adhesive for a surface protective film, an acrylic pressure-sensitive adhesive including an acrylic resin crosslinked with an isocyanate-based crosslinking agent and a metal chelate-based crosslinking agent mixed at a specific ratio is known (for example, see patent document 1).

Reference list

Patent document

Patent document 1: japanese unexamined patent application publication No. 2003-114331

Disclosure of Invention

Technical problem

Unfortunately, when the pressure-sensitive adhesive of patent document 1 known in the prior art is used for a surface protective film, there is a case where white dotted spots are left on an adherend to which the surface protective film is applied when the adherend is placed in a high-temperature high-humidity environment. The present invention has been made in view of such circumstances, and an object of the present invention is to provide a pressure-sensitive adhesive composition which suppresses an adherend to which a surface protective film is applied from being contaminated even in a case where the adherend is stored in a high-temperature and high-humidity environment.

Solution to the problem

A pressure-sensitive adhesive composition of the present invention comprises an acrylic resin (A), a curing agent (B) and a fluorine-containing additive (C). The curing agent (B) includes a polyfunctional isocyanate compound. The acrylic resin (A) is a hydroxyl-containing acrylic resin. The content of the polyfunctional isocyanate compound is 1 part by mass or more per 100 parts by mass of the acrylic resin (a). The content of the fluorine-containing additive (C) is 0.01 to 6 parts by mass with respect to 100 parts by mass of the acrylic resin (A).

Advantageous effects of the invention

With the surface protective film obtained by using the pressure-sensitive adhesive composition of the present invention, even after the surface protective film is applied to an adherend and the adherend is placed in a high-temperature high-humidity environment, the adherend can be suppressed from being contaminated.

Detailed Description

The pressure-sensitive adhesive composition of the present invention comprises an acrylic resin (a), a curing agent (B), and a fluorine-containing additive (C).

The acrylic resin (a) is a hydroxyl group-containing acrylic resin, and is preferably a (co) polymer of a monomer (mixture) including a hydroxyl group-containing monomer (a1) and a (meth) acrylate (a 2).

It is to be noted that in the present invention, "(meth) acrylic acid" means acrylic acid and/or methacrylic acid, and "(meth) acrylate" means acrylate and/or methacrylate.

The hydroxyl group-containing monomer (a1) may be one or more hydroxyl group-containing monomers, and examples thereof include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, 1, 4-cyclohexanedimethanol (meth) acrylate, polyethylene glycol mono (meth) acrylate and glycerol monomethacrylate. In particular, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate and 4-hydroxybutyl (meth) acrylate are preferable.

The content of the hydroxyl group-containing monomer (a1) is preferably 0.5 parts by mass or more, more preferably 1 part by mass or more, and even more preferably 3 parts by mass or more, and is preferably 30 parts by mass or less, more preferably 15 parts by mass or less, and even more preferably 12 parts by mass or less, relative to 100 parts by mass of the total monomer (mixture).

The (meth) acrylate (a2) may be one or more (meth) acrylates, examples of which include: aliphatic (meth) acrylates such as methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, isopropyl (meth) acrylate, n-butyl (meth) acrylate, isobutyl (meth) acrylate, t-butyl (meth) acrylate, n-pentyl (meth) acrylate, isoamyl (meth) acrylate, neopentyl (meth) acrylate, hexyl (meth) acrylate, heptyl (meth) acrylate, n-octyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, isooctyl (meth) acrylate, n-nonyl (meth) acrylate, isononyl (meth) acrylate, n-decyl (meth) acrylate, isodecyl (meth) acrylate, undecyl (meth) acrylate, dodecyl (meth) acrylate, tridecyl (meth) acrylate, dodecyl (meth) acrylate, n-pentyl (meth) acrylate, neopentyl (meth) acrylate, hexyl (meth) acrylate, ethyl acrylate, hexyl (acrylate, ethyl (meth) acrylate, ethyl acrylate, butyl acrylate, tetradecyl (meth) acrylate, n-octadecyl (meth) acrylate, and isostearyl (meth) acrylate; alicyclic (meth) acrylates such as cyclohexyl (meth) acrylate, isobornyl (meth) acrylate, dicyclopentenyl (meth) acrylate and dicyclopentenyloxyethyl (meth) acrylate; alkoxyalkylene glycol (meth) acrylates such as methoxyethylene glycol (meth) acrylate and ethoxyethylene glycol (meth) acrylate; and alkoxypolyalkylene glycol (meth) acrylates such as methoxypolyethylene glycol (meth) acrylate, ethoxypolyethylene glycol (meth) acrylate, and methoxypolypropylene glycol (meth) acrylate.

In particular, it is preferable to include aliphatic (meth) acrylates and alkoxypolyalkylene glycol (meth) acrylates.

The carbon number of the hydrocarbon group bonded to the (meth) acryloyloxy group of the aliphatic (meth) acrylate or the alicyclic (meth) acrylate is preferably not less than one, and preferably not more than 20, more preferably not more than 14, even more preferably not more than 10, and particularly preferably not more than 8.

In particular, it is preferable that the aliphatic (meth) acrylate includes a (meth) acrylate containing a linear or branched alkyl group having 4 or more and 14 or less carbon atoms (more preferably not more than 10 carbon atoms, and even more preferably not more than 8 carbon atoms). More preferably, the aliphatic (meth) acrylate comprises n-butyl (meth) acrylate and/or 2-ethylhexyl (meth) acrylate. Preferably, the (meth) acrylate containing a linear or branched alkyl group having 4 or more and 14 or less carbon atoms is an alkyl acrylate containing a linear or branched alkyl group having 4 or more and 14 or less carbon atoms.

In particular, in the case where the alkyl group is a branched alkyl group, the alkyl group may have 12 or more and 20 or less carbon atoms. In the case of a straight-chain alkyl group, if the number of carbon atoms is high (for example, 12 or more), crystallinity is formed, which makes it difficult to express pressure-sensitive adhesion. However, in the case of a branched alkyl group, the formation of crystallinity can be suppressed even when the number of carbon atoms is high.

Further, it is preferable that the (meth) acrylic acid ester (a2) includes an alkyl (meth) acrylate containing an alkyl group having 1 or more and 3 or less carbon atoms (more preferably, not more than 2 carbon atoms). More preferably, the (meth) acrylate (a2) comprises methyl (meth) acrylate. Preferably, the (meth) acrylate containing an alkyl group having 1 or more and 3 or less carbon atoms is an alkyl methacrylate.

The content of the alkyl (meth) acrylate containing an alkyl group having 1 or more and 3 or less carbon atoms is preferably 1 part by mass or more, and more preferably 2 parts by mass or more, and preferably 50 parts by mass or less, and more preferably 40 parts by mass or less with respect to 100 parts by mass of the (meth) acrylate (a2) containing an alkyl group having 4 or more and 14 or less carbon atoms.

The percentage content of the (meth) acrylic acid ester (a2) is preferably 50% by mass or more, more preferably 70% by mass or more, and even more preferably 90% by mass or more, and preferably 99% by mass or less, and more preferably 98% by mass or less, based on the total amount of the monomer mixture.

Preferably, the monomer (mixture) further comprises a carboxyl group-containing monomer (a 3).

The carboxyl group-containing monomer (a3) may be one or more carboxyl group-containing monomers, and examples thereof include unsaturated monobasic acids such as (meth) acrylic acid; (meth) acrylates of monobasic acids, such as beta-carboxyethyl (meth) acrylate and 2- (meth) acryloylpropionic acid; unsaturated dibasic acids such as crotonic acid, itaconic acid, maleic acid, fumaric acid, phthalic acid, and succinic acid; half (meth) acrylate esters of the aforementioned unsaturated dibasic acids; anhydrides of the aforementioned unsaturated dibasic acids; and each of the aforementioned unsaturated dibasic acids in which a (meth) acryloyloxyalkyl group (preferably, a (meth) acryloyloxyethyl group) is bonded to at least one of these carboxyl groups. In particular, unsaturated monobasic acids are preferred, and acrylic acid is particularly preferred.

The content of the carboxyl group-containing monomer (a3) is preferably 0.01 part by mass or more, and more preferably 0.05 part by mass or more, and preferably 10 parts by mass or less, more preferably 5 parts by mass or less, and even more preferably 1 part by mass or less, relative to 100 parts by mass of the monomer (mixture).

The monomer (mixture) may include one or more additional monomers (a4) that are different from the hydroxyl-containing monomer (a1), (meth) acrylate (a2), and carboxyl-containing monomer (a 3). Examples of the one or more additional monomers (a4) include nitrogen-containing functional group-containing monomers, ketone group-containing monomers, silyl group-containing monomers, and phosphate group-containing monomers.

A nitrogen functional group is a functional group that contains a nitrogen atom. Examples of the monomer having a nitrogen-containing functional group include cyclic amides such as N-vinylpyrrolidone, N-vinylpiperidone, N-vinylmorpholinone, N-vinylcaprolactam, N-cyclohexylmaleimide, N-butylmaleimide, N-phenylmaleimide, N- (meth) acryloylmorpholine, N- (meth) acryloylpyrrolidone, N- (meth) acryloylpiperidine, N- (meth) acryloylpyrrolidine and N- (meth) acryloyl-4-piperidone; substituted (meth) acrylamides such as (meth) acrylonitrile, (meth) acrylamide, N-dimethyl (meth) acrylamide, N-diethyl (meth) acrylamide, N-methylol (meth) acrylamide, N-methoxymethyl (meth) acrylamide, N-butoxymethyl (meth) acrylamide, N-methylenebis (meth) acrylamide, N-isopropyl (meth) acrylamide, N-dimethylaminopropyl (meth) acrylamide and dimethylaminopropyl (meth) acrylamide; amino group-containing (meth) acrylates such as dimethylaminoethyl (meth) acrylate, dimethylaminopropyl (meth) acrylate, diethylaminoethyl (meth) acrylate, and t-butylaminoethyl (meth) acrylate.

Examples of the ketone group-containing monomer include diacetone (meth) acrylamide.

Examples of the silyl group containing monomer include 3- (meth) acryloyloxypropyltrimethoxysilane and 3- (meth) acryloyloxypropylmethyldimethoxysilane.

Examples of the phosphate group-containing monomer include phosphate esters of polyethylene glycol mono (meth) acrylate (e.g., sipome PAM-100, manufactured by Rhodia Nicca ltd.).

The percentage content of the additional monomer(s) (a4) is preferably 20% by mass or less, more preferably 10% by mass or less, even more preferably 5% by mass or less, still more preferably 1% by mass or less, still even more preferably 0.1% by mass or less, and particularly preferably 0% by mass, based on the total amount of the monomer mixture.

The acrylic resin (a) may be prepared by polymerizing a monomer mixture. Examples of the method for polymerization include a radical polymerization method, an anionic polymerization method, and a cationic polymerization method. Radical polymerization is preferred. Specifically, the radical polymerization method may be a method in which a monomer mixture, a polymerization initiator, and an optionally used organic solvent are mixed together and stirred to promote polymerization.

The polymerization initiator may be one or more polymerization initiators, and examples thereof include peroxide initiators and azo initiators.

Examples of peroxide initiators include dilauroyl peroxide, 1, 3, 3-tetramethylbutyl peroxy-2-ethylhexanoate, disuccinic acid peroxide, 2, 5-dimethyl-2, 5-bis (2-ethylhexanoylperoxide) hexane, tert-butyl peroxyisobutyrate, tert-butyl peroxy-2-ethylhexanoate, tert-amyl peroxyisobutyrate, tert-amyl peroxy-2-ethylhexanoate, tert-hexyl peroxy2-ethylhexanoate, tert-hexyl peroxypivalate, bis (3-methylbenzoyl) peroxide, benzoyl peroxide (3-methylbenzoyl) and dibenzoyl peroxide.

Examples of the azo initiator include 2, 2 '-azobis (4-methoxy-2, 4-dimethylvaleronitrile), 2' -azobis (isobutyronitrile), 2 '-azobis (2-methylbutyronitrile) and 1, 1' -azobis (cyclohexane-1-carbonitrile).

In the polymerization, a chain transfer agent may be present at the same time. Examples of chain transfer agents include lauryl mercaptan, glycidyl mercaptan, thioglycolic acid, 2-mercaptoethanol, thioglycolic acid, 2-ethylhexyl thioglycolate, alpha-pinene, beta-pinene, terpinolene, and alpha-methylstyrene dimer. These chain transfer agents may be used alone or in combination of two or more.

Preferably, the polymerization temperature is 20 ℃ or more and 100 ℃ or less. In particular, in the case of using a thermal decomposition initiator such as an azo initiator or a persulfate initiator, in the case of a thermal decomposition initiator, regarding the polymerization temperature, selecting a thermal decomposition initiator having a 10-hour half-life temperature within or close to the reaction temperature makes it easy to control the reaction, so that the amount of the undecomposed initiator remaining at the end of the reaction can be reduced.

The weight average molecular weight of the obtained acrylic resin (a) is preferably 100,000 or more, more preferably 300,000 or more, and even more preferably 500,000 or more, and preferably 2,000,000 or less, and more preferably 1,000,000 or less, from the viewpoint of adhesion.

In the present specification, the weight average molecular weight can be determined by Gel Permeation Chromatography (GPC) using polystyrene standards.

In emulsion polymerization, a branched structure due to hydrogen abstraction tends to be formed in the production of an acrylic resin, and branching tends to occur, as compared with solvent polymerization. In some cases, depending on the degree of branching and the type of column chosen for GPC measurements, the molecular weight cannot be measured accurately. In this case, the GPC molecular weight measurement shows one shoulder on the high molecular weight side. It is preferable that the weight average molecular weight of the acrylic resin is within the above molecular weight range and has a single symmetrical peak in GPC measurement.

The curing agent (B) includes a polyfunctional isocyanate compound. The polyfunctional isocyanate compound may be one or more polyfunctional isocyanate compounds, examples of which include polyisocyanates such as toluene diisocyanate, chlorobenzene diisocyanate, hexamethylene diisocyanate, tetramethylene diisocyanate, xylene diisocyanate, isophorone diisocyanate, diphenylmethane diisocyanate and hydrogenated diphenylmethane diisocyanate; a trimethylolpropane adduct thereof; isocyanurates thereof; a biuret thereof; an adduct thereof; and polymethylene polyphenyl polyisocyanates.

The content of the polyfunctional isocyanate compound is 1 part by mass or more, and preferably 2 parts by mass or more, and preferably 10 parts by mass or less, more preferably 7 parts by mass or less, and even more preferably 5 parts by mass or less with respect to 100 parts by mass of the acrylic resin (a).

In the curing agent (B), the percentage content of the polyfunctional isocyanate compound is preferably 50% by mass or more, more preferably 70% by mass or more, and even more preferably 80% by mass or more, and preferably 100% by mass or less.

Preferably, the curing agent (B) further comprises at least one selected from the group consisting of a metal chelate curing agent and an epoxy crosslinking agent.

The metal chelate curing agent may be one or more metal chelate curing agents, and examples thereof include compounds comprising a metal and a chelating agent coordinated thereto. The metal may be one or more metals, examples of which include polyvalent metals such as aluminum, iron, copper, zinc, tin, titanium, nickel, antimony, magnesium, vanadium, chromium, and zirconium. In particular, aluminum, titanium, zirconium, and the like are preferable.

The chelating agent may be one or more chelating agents, and examples thereof include β -dicarbonyl compounds and carbonyl compounds containing a hydroxyl group or an amino group at the β -position. Examples of the β -dicarbonyl compounds include β -diketone compounds such as acetylacetone, 2, 4-hexanedione, 2, 4-heptanedione, 3, 5-heptanedione, 2, 4-octanedione, 3, 5-octanedione, 2, 4-nonanedione, 3, 5-nonanedione, and 5-methyl-2, 4-hexanedione; β -ketoester compounds such as methyl acetoacetate, ethyl acetoacetate, propyl acetoacetate, isopropyl acetoacetate, butyl acetoacetate, isobutyl acetoacetate, sec-butyl acetoacetate, tert-butyl acetoacetate, 2-ethylhexyl acetoacetate, and dodecyl acetoacetate (preferably, alkyl acetoacetate having 1 to 20 carbon atoms); and β -diester compounds such as diethyl malonate. Examples of carbonyl compounds containing a hydroxyl group or an amino group at the β -position include diacetone alcohol, diacetone amine, salicylaldehyde, methyl salicylate, and N-methyl salicylamide. In particular, β -dicarbonyl compounds are preferred, and β -diketone compounds are preferred.

Preferably, the metal chelate curing agent is preferably a compound in which a β -dicarbonyl compound (preferably, a β -diketone compound) is coordinated with aluminum, titanium, zirconium, or the like.

In the case where the metal chelate curing agent is included, the content of the metal chelate curing agent is preferably 0.1 part by mass or more, more preferably 0.5 part by mass or more, and even more preferably 1 part by mass or more, and is preferably 10 parts by mass or less, more preferably 7 parts by mass or less, and even more preferably 5 parts by mass or less, relative to 100 parts by mass of the polyfunctional isocyanate compound.

The epoxy curing agent may be one or more epoxy curing agents, examples of which include bisphenol a epichlorohydrin type epoxy resin, ethylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, glycerol triglycidyl ether, 1, 6-hexanediol diglycidyl ether, trimethylolpropane triglycidyl ether, sorbitol polyglycidyl ether, polyglycerol polyglycidyl ether, pentaerythritol polyglycidyl erythritol, diglycerol polyglycidyl ether, 1, 3-bis (N, N-diglycidylaminomethyl) cyclohexane, and N, N' -tetraglycidyl-m-xylylenediamine.

In the case where the epoxy curing agent is included, the content of the epoxy curing agent is preferably 0.1 parts by mass or more, more preferably 0.5 parts by mass or more, and even more preferably 1 part by mass or more, and is preferably 10 parts by mass or less, more preferably 7 parts by mass or less, and even more preferably 5 parts by mass or less, with respect to 100 parts by mass of the polyfunctional isocyanate compound.

The curing agent (B) may include an additional curing agent other than the polyfunctional isocyanate compound, the metal chelate curing agent and the epoxy crosslinking agent. The additional curing agent may be one or more additional curing agents, examples of which include polyvalent metal salt curing agents, ketone-hydrazide curing agents, amine-containing curing agents, and the like,

An oxazoline curing agent, a silane curing agent, an aziridine curing agent, a melamine curing agent, and an aldehyde curing agent. The content of the additional curing agent is preferably 10% by mass or less, more preferably 5% by mass or less based on the total amount of the curing agent (B),and even more preferably 1 mass% or less.

The content of the curing agent (B) is preferably 1 part by mass or more, and more preferably 1.5 parts by mass or more, and preferably 10 parts by mass or less, more preferably 8 parts by mass or less, and even more preferably 6 parts by mass or less with respect to 100 parts by mass of the acrylic resin (a).

The fluorine-containing additive (C) may preferably be a fluorine-containing surfactant, more preferably a surfactant in which a fluorinated hydrocarbon group is included as a hydrophobic group, and even more preferably a fluorinated hydrocarbon group-containing anionic surfactant, a fluorinated hydrocarbon group-containing nonionic surfactant, a fluorinated hydrocarbon group-containing amphoteric surfactant, or the like. Preferably, the fluorinated hydrocarbon group is a fluorinated alkyl group having 1 to 10 carbon atoms or a fluorinated alkenyl group having 1 to 10 carbon atoms.

The anionic surfactant containing a fluorinated hydrocarbon group may be one or more anionic surfactants containing a fluorinated hydrocarbon group, and examples thereof include anionic surfactants containing a fluorinated hydrocarbon group and a hydroxyl group, anionic surfactants containing a fluorinated hydrocarbon group and a carboxyl group, and surfactants containing a fluorinated hydrocarbon group and a sulfonic acid group.

The fluorocarbon group-containing nonionic surfactant may be one or more fluorocarbon group-containing nonionic surfactants, examples of which include alkylene oxide (preferably, ethylene oxide) adducts and/or episulfane adducts of fluorocarbons, and alkyl ethers of alkylene oxide (preferably, ethylene oxide) adducts and/or episulfane adducts of fluorocarbons.

The fluorine-containing additive (C) may be an additive containing an organosilyl and/or dialkylsiloxane chain.

The content of the fluorine-containing additive (C) is preferably 0.01 parts by mass or more, and more preferably 0.03 parts by mass or more, and preferably 6 parts by mass or less, more preferably 3 parts by mass or less, and even more preferably 2 parts by mass or less with respect to 100 parts by mass of the acrylic resin (a).

Preferably, the pressure-sensitive adhesive composition of the present invention further comprises an antioxidant (D). Examples of the antioxidant (D) include radical scavenging primary antioxidants such as phenolic antioxidants and amine-based antioxidants; and peroxide decomposition secondary antioxidants such as phosphorus-based antioxidants and sulfur-based antioxidants.

Examples of the phenolic antioxidant include triethylene glycol-bis- [3- (3-tert-butyl-5-methyl-4-hydroxyphenyl) propionate]Pentaerythritol tetrakis [3- (3, 5-di-tert-butyl-4-hydroxyphenyl) propionate, octadecyl [3- (3, 5-di-tert-butyl-4-hydroxyphenyl) propionate, thiodiethylene bis [3- (3, 5-di-tert-butyl-4-hydroxyphenyl) propionate]3, 5-bis (1, 1-dimethylethyl) -4-hydroxy-C phenylpropionic acid₇-C₉Side chain alkyl esters, 4, 6-bis (dodecylthiomethyl) -o-cresol, the reaction product of phenylaniline and 2, 4, 4-trimethylpentene, 2-tert-butyl-6- (3-tert-butyl-2-hydroxy-5-methylbenzyl) -4-methylphenyl acrylate, 3, 9-bis [2- [3- (tert-butyl-4-hydroxy-5-methylphenyl) propionyloxy]-1, 1-Dimethylethyl]-2, 4, 8, 10-tetraoxaspiro [5.5 ]]Undecane, 2, 6-di-tert-butyl-4-methylphenol, 2' -methylenebis (4-methyl-6-tert-butylphenol) and 2, 5-di-tert-amyl-hydroquinone.

Examples of the amine-based antioxidant include bis (2, 2, 6, 6-tetramethyl-4-piperidyl) sebacate, bis (1, 2, 2, 6, 6-pentamethyl-4-piperidyl) sebacate, 1, 2, 3, 4-tetrakis (2, 2, 6, 6-tetramethyl-4-piperidyloxycarbonyl) butane, a polycondensate of dimethyl succinate and 1- (2-hydroxyethyl) -4-hydroxy-2, 2, 6, 6-tetramethylpiperidine, 1- (3, 5-di-t-butyl-4-hydroxyphenyl) -1, 1-bis (2, 2, 6, 6-tetramethyl-4-piperidyloxycarbonyl) pentane, N-bis (3-aminopropyl) ethylenediamine, N-methyl-4-piperidyl-oxocarbonyl) pentane, and the like, 4-benzoyloxy-2, 2, 6, 6-tetramethylpiperidine, bis (octyloxy (octylon) -2, 2, 6, 6-tetramethyl-4-piperidyl) sebacate and bis (1, 2, 2, 6, 6-pentamethyl-4-piperidyl) [ [3, 5-bis (1, 1-dimethylethyl) -4-hydroxyphenyl ] methyl ] butyl malonate.

Examples of the phosphorus-based antioxidant include triphenylphosphine, bis (2, 4-di-t-butyl-6-methylphenyl) ethyl phosphite, triphenyl phosphite, trisnonylphenyl phosphite, tris (2, 4-dibutylphenyl) phosphite, tris (2, 4-dibutyl-5-methylphenyl) phosphite, tris [ 2-t-butyl-4- (3-butyl-4-hydroxyphenyl) phosphite5-Methylphenylthio) -5-methylphenyl radical]Esters, tris (2, 4-di-tert-butylphenyl) phosphite, tridecyl phosphite, octyldiphenyl phosphite, ditecyl monophenyl phosphite, ditridecyl pentaerythritol diphosphite, bis (nonylphenyl) pentaerythritol diphosphite, bis (2, 4-dibutylphenyl) pentaerythritol diphosphite, bis (2, 6-dibutyl-4-methylphenyl) pentaerythritol diphosphite, bis (2, 4, 6-tributylphenyl) pentaerythritol diphosphite, bis (2, 4-dicumylphenyl) pentaerythritol diphosphite, tetra (tridecyl) isopropylidenediphenol diphosphite, tetra (tridecyl) -4, 4' -n-butylidene bis (2-butyl-5-methylphenol) diphosphite, hexa (tridecyl) -1, 1, 3-tris (2-methyl-4-hydroxy-5-butylphenyl) butanetriphosphite, tetrakis (2, 4-dibutylphenyl) biphenylene diphosphonite, 9, 10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, 2 ' -methylenebis (4, 6-butylphenyl) -2-ethylhexyl phosphite, 2 ' -methylenebis (4, 6-butylphenyl) -octadecyl phosphite, 2 ' -ethylenebis (4, 6-dibutylphenyl) fluorophosphite, tris (2- [ (2, 4, 8, 10-tetrabutyldibenzo [ d, f ] s][1，3，2]II

Phosphaheptin-6-yl) oxy]Ethyl) amine and phosphites of 2-ethyl-2-butylpropanediol and 2, 4, 6-tributylphenol.

Examples of the sulfur-based antioxidant include dilauryl-3, 3 '-thiopropionate, dilauryl-3, 3' -thiodipropionate, dilauryl thiodipropionate, ditridecyl-3, 3 '-thiodipropionate, dimyristyl-3, 3' -thiodipropionate, distearyl-3, 3 '-thiodipropionate, tetrakis-methylene-3-laurylthiopropionate methane, distearyl-3, 3' -methyl-3, 3 '-thiodipropionate, laurylstearyl-3, 3' -thiodipropionate, bis [ 2-methyl-4- (3-n-alkylthio-propionyloxy) -5-tert-butylphenyl ] sulfide, and mixtures thereof, Beta-lauryl thiopropionate, 2-mercaptobenzimidazole, 2-mercapto-5-methylbenzimidazole and dioctadecyl-3, 3' -thiodipropionate.

In particular, the antioxidant (D) is preferably a primary antioxidant, and more preferably a phenolic antioxidant. In the antioxidant (D), the content of the primary antioxidant (preferably, phenolic antioxidant) is preferably 80% by mass or more, and more preferably 90% by mass or more, and 100% by mass or less.

In the case where the antioxidant (D) is included, the content of the antioxidant (D) is preferably 0.01 parts by mass or more, and more preferably 0.03 parts by mass or more, and preferably 2 parts by mass or less, more preferably 1 part by mass or less, and even more preferably 0.5 parts by mass or less, relative to 100 parts by mass of the acrylic resin (a).

The pressure-sensitive adhesive composition of the present invention may further comprise a solvent (E). The solvent (E) may be one or more solvents, and is preferably a solvent that does not interfere with the reaction with the isocyanate-based crosslinking agent. Examples of the solvent (E) include aromatic hydrocarbon solvents such as toluene, o-xylene, m-xylene and p-xylene; ester solvents such as methyl acetate, ethyl acetate and butyl acetate; ketone solvents such as methyl ethyl ketone, methyl isobutyl ketone, acetone, cyclohexanone and 3-pentanone; and hydrocarbon solvents such as hexane and heptane, cyclohexane and methylcyclohexane.

The content of the solvent (E) is preferably 10 parts by mass or more and preferably 2,000 parts by mass or less with respect to 100 parts by mass of the acrylic polymer (a).

The pressure-sensitive adhesive composition of the present invention may further contain one or more additional additives, examples of which include tackifying resins, colorants such as pigments and dyes, plasticizers, softeners, antioxidants, fillers, film formers, leveling agents, wetting agents, thickeners (viscosity modifiers), water repellents, and defoamers. In the case where the resin composition contains one or more additional additives, it is preferable that the content of the one or more additional additives is more than 0 part by mass and 30 parts by mass or less with respect to 100 parts by mass of the acrylic resin (a).

A pressure-sensitive adhesive layer formed of the pressure-sensitive adhesive composition of the present invention and a pressure-sensitive adhesive film or sheet including such a pressure-sensitive adhesive layer are also encompassed in the technical scope of the present invention. The pressure-sensitive adhesive film or sheet is preferably a pressure-sensitive adhesive film or sheet comprising a substrate layer and a pressure-sensitive adhesive layer formed from the pressure-sensitive adhesive composition of the present invention, and more preferably a pressure-sensitive adhesive film or sheet comprising a substrate layer, such a pressure-sensitive adhesive layer and a release film layer (preferably, laminated in this order).

The substrate layer is preferably a layer of a plastic substrate and may be in the form of a sheet or film. Examples of plastics include: polyesters such as polyethylene terephthalate, polyethylene naphthalate and polybutylene terephthalate; a polyolefin; poly (meth) acrylates; polyvinyl chloride; polyethylene; polypropylene/ethylene vinyl alcohol; polyurethanes, polyamides, and polyimides. The surface of the substrate layer may be, for example, a release-treated, antistatic-treated, and/or corona-treated surface. Preferably, the thickness of the base material layer is 2 μm or more and 200 μm or less.

The method for producing the pressure-sensitive adhesive film or sheet may be, for example, a method in which a pressure-sensitive adhesive composition is coated on a plastic substrate, then dried and cured to obtain a pressure-sensitive adhesive layer, and, as necessary, a release film is laminated on the pressure-sensitive adhesive layer.

When the resin composition, the pressure-sensitive adhesive composition, and the pressure-sensitive adhesive sheet of the invention are used for a surface protective film, even in the case where an adherend is left in a high-temperature high-humidity environment, the adherend can be suppressed from being contaminated by the surface protective film. Therefore, the resin composition, the pressure-sensitive adhesive composition, and the pressure-sensitive adhesive sheet of the present invention are suitable for use in a wide variety of industrial applications such as automobiles, electronic devices, and household appliances, and are particularly useful for a surface protective film used in forming glass articles to be used in electronic devices (e.g., portable electronic terminal devices and PC tablet computers).

Examples

The present invention will now be described in more detail with reference to examples.

[ Synthesis example 1]

To a reaction vessel equipped with a stirrer, a reflux condenser, a nitrogen inlet tube, and a thermometer, 692 parts by mass of 2-ethylhexyl acrylate, 250 parts by mass of methyl acrylate, 56 parts by mass of 4-hydroxybutyl acrylate, 2.0 parts by mass of acrylic acid, and 1330 parts by mass of ethyl acetate were placed, and with stirring, the temperature was increased to 70 ℃ while injecting nitrogen. Subsequently, 20 parts by mass (5% by mass based on solids) of a solution of azobisisobutyronitrile dissolved in ethyl acetate in advance was added. Subsequently, the resultant was kept at 72 ℃ for 8 hours with stirring, after which 980 parts by mass of ethyl acetate was added, and the content was cooled and then filtered through a 200-mesh wire sieve. An acrylic polymer (A-1) solution having a non-volatile content of 29.9 mass% and a viscosity of 10,600 mPas was obtained.

[ Synthesis example 2]

Into a reaction vessel equipped with a stirrer, a reflux condenser, a nitrogen inlet pipe, and a thermometer, 785 parts by mass of 2-ethylhexyl acrylate, 145 parts by mass of methoxypolyethylene glycol #400 acrylate (NK ester AM-90G, manufactured by Shin-Nakamura Chemical co., ltd.), 70 parts by mass of 2-hydroxyethyl acrylate, and 1200 parts by mass of ethyl acetate were placed, and with stirring, the temperature was raised to 70 ℃ while injecting nitrogen. Subsequently, 20 parts by mass (5% by mass based on solids) of a solution of azobisisobutyronitrile dissolved in ethyl acetate in advance was added. Subsequently, the resultant was kept at 72 ℃ for 8 hours with stirring, after which 280 parts by mass of ethyl acetate was added, and the content was cooled and then filtered through a 200-mesh wire sieve. An acrylic polymer (A-2) solution having a non-volatile content of 40.0 mass% and a viscosity of 1300 mPas was obtained.

[ Synthesis example 3]

Into a reaction vessel equipped with a stirrer, a reflux condenser, a nitrogen inlet tube, and a thermometer, 898 parts by mass of 2-ethylhexyl acrylate, 2.0 parts by mass of acrylic acid, 100 parts by mass of 4-hydroxybutyl acrylate, 730 parts by mass of ethyl acetate, and 250 parts by mass of methyl ethyl ketone were placed, and with stirring, the temperature was increased to 70 ℃ while injecting nitrogen. Subsequently, 20 parts by mass (5% by mass based on solids) of a solution of azobisisobutyronitrile dissolved in ethyl acetate in advance was added. Subsequently, the resultant was kept at 72 ℃ for 8 hours with stirring, after which 220 parts by mass of ethyl acetate was added, and the content was cooled and then filtered through a 200-mesh wire sieve. An acrylic polymer (A-3) solution having a nonvolatile content of 45.0% by mass and a viscosity of 1900 mPas was obtained.

[ example 1]

To 100 parts by mass of the acrylic polymer (a-1) of synthesis example 1, 0.1 part by mass of Irganox 1010 (manufactured by BASF SE) as an antioxidant was added. Immediately before the preparation of the pressure-sensitive adhesive film, 1.5 parts by mass of Megaface F-562 (manufactured by DIC Corporation) as a fluorine-containing additive and 2.0 parts by mass of Duranate TKA-100 (manufactured by Asahi Kasei Chemicals Corporation) as a crosslinking agent were added to the resultant. Thus, a pressure-sensitive adhesive (1) was prepared.

[ example 2]

To 100 parts by mass of the acrylic polymer (A-1) of Synthesis example 1, 0.1 part by mass of Megaface F-562 (manufactured by DIC Corporation) as a fluorine-containing additive, 3.0 parts by mass of Duranate TKA-100 (manufactured by Asahi Kasei Chemicals Corporation) as a crosslinking agent, and 0.05 parts by mass of aluminum tris (acetylacetonate) were added immediately before the preparation of a pressure-sensitive adhesive film. Thus, a pressure-sensitive adhesive (2) was prepared.

[ example 3]

To 100 parts by mass of the acrylic polymer (a-1) of synthesis example 1, 0.1 part by mass of Irganox 1010 (manufactured by BASF SE) as an antioxidant was added. Immediately before the preparation of the pressure-sensitive adhesive film, 0.2 parts by mass of Megaface F-562 (manufactured by DIC Corporation) as a fluorine-containing additive, 2.5 parts by mass of Duranate TSS-100 (manufactured by Asahi Kasei Chemicals Corporation) as a crosslinking agent, and 0.1 parts by mass of aluminum tris (acetylacetonate) were added to the resultant. Thus, a pressure-sensitive adhesive (3) was prepared.

[ example 4]

To 100 parts by mass of the acrylic polymer (a-1) of synthesis example 1, 0.1 part by mass of Irganox 1010 (manufactured by BASF SE) as an antioxidant was added. Immediately before the preparation of the pressure-sensitive adhesive film, 0.1 parts by mass of Megaface F-562 (manufactured by DIC Corporation) as a fluorine-containing additive, 3.5 parts by mass of BURNOCK D-750 (manufactured by DIC Corporation) as a crosslinking agent, and 0.1 parts by mass of aluminum tris (acetylacetonate) were added to the resultant. Thus, a pressure-sensitive adhesive (4) was prepared.

[ example 5]

To 100 parts by mass of the acrylic polymer (a-1) of synthesis example 1, 0.1 part by mass of Irganox 1010 (manufactured by BASF SE) as an antioxidant was added. Immediately before the preparation of the pressure-sensitive adhesive film, 0.2 parts by mass of Megaface F-562 (manufactured by DIC Corporation) as a fluorine-containing additive, 2.0 parts by mass of Duranate TKA-100 (manufactured by Asahi Kasei Chemicals Corporation) as a crosslinking agent, and 0.05 parts by mass of TETRAD-X (manufactured by MITSUBISHI GAS CHEMICAL COMPANY, INC.) were added to the resultant. Thus, a pressure-sensitive adhesive (5) was prepared.

[ example 6]

To 100 parts by mass of the acrylic polymer (A-2) of Synthesis example 2, 0.05 parts by mass of Megaface F-562 (manufactured by DIC Corporation) as a fluorine-containing additive, 3.0 parts by mass of Duranate TKA-100 (manufactured by Asahi Kasei Chemicals Corporation) as a crosslinking agent, and 0.1 parts by mass of aluminum tris (acetylacetonate) were added. Thus, a pressure-sensitive adhesive (6) was prepared.

[ example 7]

To 100 parts by mass of the acrylic polymer (a-3) of synthesis example 3, 0.1 part by mass of Irganox 1010 (manufactured by BASF SE) as an antioxidant was added. Immediately before the preparation of the pressure-sensitive adhesive film, 0.2 parts by mass of Megaface F-562 (manufactured by DIC Corporation) as a fluorine-containing additive, 5.0 parts by mass of Duranate TKA-100 (manufactured by Asahi Kasei Chemicals Corporation) as a crosslinking agent, and 0.1 parts by mass of aluminum tris (acetylacetonate) were added to the resultant. Thus, a pressure-sensitive adhesive (7) was prepared.

Comparative example 1

To 100 parts by mass of the acrylic polymer (A-1) of Synthesis example 1, 3.0 parts by mass of Duranate TKA-100 (manufactured by Asahi Kasei Chemicals Corporation) as a crosslinking agent was added immediately before the preparation of a pressure-sensitive adhesive film. Thus, a pressure-sensitive adhesive (X1) was prepared.

Comparative example 2

To 100 parts by mass of the acrylic polymer (A-1) of Synthesis example 1, 7 parts by mass of Megaface F-562 (manufactured by DIC Corporation), 4.0 parts by mass of BURNOCK D-750 (manufactured by DIC Corporation) were added immediately before the preparation of the pressure-sensitive adhesive film. Thus, a pressure-sensitive adhesive (X2) was prepared.

Comparative example 3

To 100 parts by mass of the acrylic polymer (A-1) of Synthesis example 1, 0.3 parts by mass of KS-7002 (manufactured by Shin-Etsu Chemical Co., Ltd.) and 4 parts by mass of Duranate TSS-100 (manufactured by Asahi Kasei Chemicals Corporation) were added immediately before the preparation of a pressure-sensitive adhesive film. Thus, a pressure-sensitive adhesive (X3) was prepared.

[ method of Forming pressure-sensitive adhesive film ]

Each of the pressure-sensitive adhesives (1) to (7) and (X1) to (X3) mixed with a crosslinking agent was coated on the surface of a polyethylene terephthalate (PET) film having a thickness of 6 μm in such a manner that the dry film thickness of the pressure-sensitive adhesive was 6 μm, and then dried at 80 ℃ for 3 minutes. A PET film having a thickness of 38 μm and a surface treated with a release agent was laminated on the resultant, and then cured at 40 ℃ for 3 days to obtain a test piece.

[ method for inspecting contamination status of adherend after high temperature test ]

Test pieces prepared using the above method were applied to both sides of the glass sheet. The resultant was subjected to heat treatment at 200 ℃ for 1 hour, at room temperature for 30 minutes, at 100 ℃ for 1 hour, at room temperature for 30 minutes, at 140 ℃ for 45 minutes, and then left to stand at 23 ℃ for 30 minutes. The pressure-sensitive adhesive film was peeled off from the glass sheet, and LED light was irradiated from below the glass sheet. The contamination state was checked based on the following evaluation criteria.

< evaluation criteria >

o: no pollution to glass sheet

Δ: partial contamination of the glass sheet was observed

X: the entire surface of the glass sheet is contaminated

[ method for measuring adhesive Strength ]

The test piece was prepared by cutting the test piece prepared using the above method into pieces having a width of 25 mm. The test piece was applied to the glass sheet in such a manner that the adhesion area was 25mm × 60mm by reciprocating a 2-kg roller twice. 180 degree peel strength was measured in an atmosphere of 23 ℃ and 50% RH when 20 minutes had elapsed after application. It is considered as the initial adhesion strength.

[ Table 1]

[ Table 2]

In all of examples 1 to 7 as examples of the present invention, contamination (white fog and white spots) was suppressed. In contrast, comparative examples 1 and 3 are examples in which no fluorine-containing additive is included, and comparative example 2 is an example in which the content of the fluorine-containing additive is higher than the range specified in the present invention. In all of comparative examples 1 to 3, the stain resistance was unsatisfactory.

Claims

1. A pressure sensitive adhesive composition comprising:

an acrylic resin (A);

a curing agent (B); and

a fluorine-containing additive (C), wherein

The curing agent (B) comprises a polyfunctional isocyanate compound,

the acrylic resin (A) includes a hydroxyl-containing acrylic resin,

the content of the polyfunctional isocyanate compound is 1 part by mass or more per 100 parts by mass of the acrylic resin (A), and

the content of the fluorine-containing additive (C) is 0.01 to 6 parts by mass with respect to 100 parts by mass of the acrylic resin (A).

2. The pressure-sensitive adhesive composition according to claim 1, wherein the curing agent (B) further comprises at least one selected from the group consisting of a metal chelate curing agent and an epoxy curing agent.

3. The pressure-sensitive adhesive composition according to claim 2, wherein a total content of at least one of the metal chelate curing agent and the epoxy curing agent is 1 part by mass or more and 5 parts by mass or less with respect to 100 parts by mass of the polyfunctional isocyanate compound.

4. The pressure sensitive adhesive composition according to any one of claims 1 to 3, wherein

The acrylic resin (A) comprises a copolymer of a monomer mixture comprising a hydroxyl group-containing monomer (a1) and a (meth) acrylic acid ester (a2), and

the percentage content of the hydroxyl group-containing monomer (a1) in the monomer mixture is 0.5 mass% or more and 15 mass% or less.

5. The pressure sensitive adhesive composition according to any one of claims 1 to 4, further comprising an antioxidant (D).

6. A pressure-sensitive adhesive film or sheet formed from the pressure-sensitive adhesive composition according to any one of claims 1 to 5.

7. A surface protective film comprising the film or sheet according to claim 6.