TW202313906A - Adhesive composition, adhesive layer, and adhesive film - Google Patents

Abstract

The invention relates to an adhesive composition, an adhesive layer and an adhesive film. Provided is an adhesive composition which exhibits excellent optical transparency, high adhesive strength and foaming resistance even in a high-temperature, high-humidity environment or a high-temperature, hot-water immersion environment. The present invention uses an adhesive composition characterized by comprising an acrylic polymer (A), a cross-linking agent (B), and an acrylic polymer (C), the acrylic polymer (A) comprising: a unit derived from an alkyl (meth) acrylate monomer (a1) having an alkyl group having 1-4 carbon atoms; a unit derived from a monomer (a2) having a nitrogen atom; the acrylic polymer (C) contains: a unit derived from a (meth) acrylate monomer (c1) having an alicyclic structure; a unit derived from at least one type of monomer (a3) having an acid group; and a unit derived from a (meth) acrylate monomer (c2) having a hydroxyl group. And a unit derived from an alkyl (meth) acrylate monomer (c2).

Description

Adhesive composition, adhesive layer, and adhesive film

The invention relates to an adhesive composition, an adhesive layer, and an adhesive film.

Acrylic adhesives have long been used in various fields, and especially in recent years, they are in high demand for information technology (IT)-related products such as smartphones. These IT-related products are required to have higher performance and higher functions according to their product characteristics.

As an example of acrylic adhesives used in IT-related products, heat-sensitive adhesives are required that are slightly adhesive at room temperature, show strong adhesiveness when heated, and persist after heating is released. As a specific example thereof, for example, an adhesive including an acrylic low molecular weight polymer having a weight average molecular weight of 2,000 to 9,000 has been proposed (for example, refer to Patent Document 1). In addition, there is proposed an adhesive comprising: a polymer having a glass transition temperature of less than 0°C; and a monomer having a polyorganosiloxane skeleton and a monomer having a glass transition temperature of 40°C or higher as monomer units, and A polymer having a weight average molecular weight of 10,000 to less than 100,000 (for example, refer to Patent Document 2).

To be attached to the protective film or display device surface of IT-related products with display functions such as TVs or personal computers, portable terminals, office automation (OA) equipment, car navigation, game equipment, electronic notebooks, etc. The attached member imparts visibility and requires high optical transparency. In addition, it is required to show a strong adhesive force quickly after being attached to the frame or display device, and the adhesive force will not be reduced even after being subjected to a durable environment. Previously, metal or glass was used for the surface panel of the housing or display device, but in recent years, plastic materials such as acrylic or polycarbonate have been used for the purpose of lightweighting or three-dimensional (3D) molding, etc. Adhesives that have been known for a long time have the following problem: when they are placed in a high-temperature and high-humidity environment or are immersed in high-temperature and hot water under severe durable conditions, air bubbles are generated between the base material or the adherend and the bonding surface. , the optical transparency cannot be maintained, the visibility is reduced, and it is difficult to maintain high adhesion due to foaming.

In addition, in the application of automobile exteriors or outdoor advertising materials, it is sometimes used to attach a film instead of painting or to attach a printed film to the painting, and replace it after a certain period of time. Also in this use, similarly to the above, excellent optical transparency for imparting high designability, and no reduction in adhesive force regardless of the type of adherend is required even after passing through a durable environment. [Prior art literature] [Patent Document]

[Patent Document 1] Japanese Patent No. 6618522 [Patent Document 2] Japanese Patent Laid-Open No. 2019-123884

[Problem to be Solved by the Invention]

The problem to be solved by the present invention is to provide an adhesive composition and an adhesive layer that exhibit excellent optical transparency, high adhesion, and foaming resistance even under high-temperature and high-humidity environments or under high-temperature and warm-water immersion environments. , and adhesive film. [Means to solve the problem]

The adhesive composition of the present invention includes: an acrylic polymer (A), a crosslinking agent (B) and an acrylic polymer (C). The acrylic polymer (A) includes: A unit of an alkyl (meth)acrylate monomer (a1); a unit derived from a monomer (a2) having a nitrogen atom; and a unit derived from a monomer (a3) having an acid group and a monomer having a hydroxyl group A unit of at least one of the group consisting of the monomer (a4), the glass transition temperature of the acrylic polymer (A) is -20°C or lower, and the weight average molecular weight of the acrylic polymer (A) is 100,000 As mentioned above, the content of the units derived from the alkyl (meth)acrylate monomer (a1) having an alkyl group having 1 to 4 carbon atoms is 50% by mass or more in the acrylic polymer (A) and less than 97% by mass, the acrylic polymer (C) includes: a unit derived from an alicyclic structure-containing (meth)acrylate monomer (c1); and a unit derived from an alkyl (meth)acrylate monomer (c2), the glass transition temperature of the acrylic polymer (C) is 50° C. or higher, and the weight average molecular weight of the acrylic polymer (C) is less than 100,000. [Effect of the invention]

The adhesive composition of the present invention exhibits excellent optical transparency, high adhesion, and foaming resistance even under high-temperature and high-humidity environments or under high-temperature and warm-water immersion environments, so it can be suitably used in televisions or personal Protective films for IT-related products with display functions such as computers, portable terminals, OA equipment, car navigation, game equipment, and electronic notebooks, paint protection films used in automotive exteriors, outdoor Advertising materials or protective films for indoor/outdoor building materials, etc.

The adhesive composition of the present invention includes: an acrylic polymer (A), a crosslinking agent (B) and an acrylic polymer (C).

The acrylic polymer (A) includes: a unit derived from an alkyl (meth)acrylate monomer (a1) having an alkyl group having 1 to 4 carbon atoms; a unit derived from a monomer (a2) having a nitrogen atom and a unit derived from at least one selected from the group consisting of a monomer having an acid group (a3) and a monomer having a hydroxyl group (a4).

Examples of the alkyl (meth)acrylate monomer (a1) having an alkyl group having 1 to 4 carbon atoms include methyl (meth)acrylate, ethyl (meth)acrylate, (meth)acrylate, Base) propyl acrylate, n-butyl (meth)acrylate, isobutyl (meth)acrylate, tertiary butyl (meth)acrylate, etc. These alkyl (meth)acrylate monomers (a1) can be used alone or in combination. In order to easily achieve a balance between cohesion and flexibility, it is preferable to use n-butyl acrylate or n-butyl acrylate. The content is more preferably at least 25 mass % in the alkyl (meth)acrylate monomer (a1), and more preferably at least 30 mass %.

The monomer (a2) having a nitrogen atom is a monomer having a nitrogen atom and a polymerizable double bond in the molecule, preferably a monomer having an amide bond and a polymerizable double bond in the molecule, for example: Lactamide compounds with vinyl groups; (meth)acrylamide monomers; (meth)acrylamide monomers; base) acrylate compounds, etc. These nitrogen atom-containing monomers (a2) may be used alone or in combination of two or more.

Examples of the lactam compound having a vinyl group include N-vinylpyrrolidone, N-vinylcaprolactam, and the like.

The (meth)acrylamide monomer can be listed as follows: a hydrogen atom or a hydrocarbon group (preferably an aliphatic hydrocarbon group) is bonded to the nitrogen atom of the (meth)acrylamide; wherein the - CH ₂ - may be substituted with -CO-, and the hydrogen atom contained in the hydrocarbon group may be substituted with hydroxyl), etc. In addition, when the nitrogen atom of (meth)acrylamide is substituted by two or more groups (the hydrocarbon groups), these groups may be bonded to each other to form a nitrogen atom-containing ring.

The number of carbon atoms of the hydrocarbon group (preferably an aliphatic hydrocarbon group) substituted on the nitrogen atom contained in the amide bond is preferably 1 or more, and preferably 10 or less, more preferably 6 or less.

As the (meth)acrylamide monomer, one kind or two or more kinds can be used. The (meth)acrylamide monomer can be (meth)acrylamide, N-1 substituted (meth)acrylamide compound, N,N-2 substituted (meth)acrylamide compound any kind.

As the (meth)acrylamide compound, one or more kinds can be used, for example, (meth)acrylamide; N-isopropyl (meth)acrylamide, N-(1, 1-Dimethyl-3-oxobutyl)acrylamide, N-hydroxymethyl(meth)acrylamide, N-methoxymethyl(meth)acrylamide, N-butoxy N-1 substituted (meth)acrylamide compounds such as methyl (meth)acrylamide, N-(2-hydroxymethyl)acrylamide, N-(2-hydroxyethyl)acrylamide; N -(Meth)acrylmorpholine, N-(meth)acrylpiperidone, N-(meth)acrylpiperidine, N-(meth)acrylpyrrolidine, N- (Meth)acryl-4-piperidone, N,N-dimethyl(meth)acrylamide, N,N-diethyl(meth)acrylamide, N,N-diiso N-2 substituted ( Meth)acrylamide compounds, etc.

Among them, the (meth)acrylamide monomer preferably includes the monomer represented by formula (1).

[式（1）中，R ¹表示氫原子或甲基；R ²及R ³分別獨立地表示氫原子或碳原子數1～20的烴基，該烴基中所含的-CH ₂-可經取代為-CO-或-O-，該烴基中所含的氫原子可經取代為羥基，R ²及R ³可彼此鍵結而形成包含氮原子的環] [chemical 1]

[In formula (1), R ¹ represents a hydrogen atom or a methyl group; R ² and R ³ independently represent a hydrogen atom or a hydrocarbon group with 1 to 20 carbon atoms, and the -CH ₂ - contained in the hydrocarbon group may be substituted is -CO- or -O-, the hydrogen atom contained in the hydrocarbon group may be substituted by a hydroxyl group, and ^R2 and ^R3 may be bonded to each other to form a ring containing a nitrogen atom]

The hydrocarbon groups represented by ^R2 and ^R3 may be one or more, for example, straight-chain or branched saturated aliphatic hydrocarbon groups; straight-chain or branched unsaturated fatty acids Hydrocarbon groups, etc. Among these, a linear or branched saturated aliphatic hydrocarbon group is preferred, and a branched saturated aliphatic hydrocarbon group is more preferred. Preferably at least one of R ² and R ³ is a hydrogen atom.

The (meth)acrylamide monomer is also preferably a (meth)acrylamide monomer comprising both R ² and R ³ as the hydrocarbon group. When the (meth)acrylamide monomer in which both R ² and R ³ are the hydrocarbon group is included, the content of the unit derived from the monomer is preferable in the acrylic polymer (A) It is at least 0.5% by mass, more preferably at least 1% by mass, and is preferably at most 20% by mass, more preferably at most 15% by mass.

In the monomer (a2) having a nitrogen atom, the content of units derived from the acrylamide monomer is preferably at least 70% by mass, more preferably at least 80% by mass, and still more preferably at least 90% by mass. , the upper limit is 100% by mass.

As the (meth)acrylate compound having a functional group containing a nitrogen atom (for example, an amino group, a 1-substituted amino group, a 2-substituted amino group, a nitrile group, etc.), (meth)acrylonitrile, ( tert-butylaminoethyl meth)acrylate, dimethylaminoethyl (meth)acrylate, diethylaminoethyl (meth)acrylate, and the like.

Examples of the monomer (a3) having an acid group include monomers having an acid group and a polymerizable double bond, preferably a monomer having a carboxyl group, and a monomer having a sulfo group, preferably a monomer having a carboxyl group. of monomers.

As the monomer having a carboxyl group, one kind or two or more kinds can be used, for example, (meth)acrylic acid; carboxyethyl (meth)acrylate, carboxypentyl (meth)acrylate, (meth)acrylic acid Carboxyalkyl (meth)acrylate such as β-carboxyethyl ester; unsaturated carboxylic acids such as itaconic acid, itaconic anhydride, maleic acid, maleic anhydride, fumaric acid, crotonic acid, etc.

In the monomer (a3) having an acid group, the content of the monomer having a carboxyl group is preferably at least 80% by mass, more preferably at least 90% by mass, still more preferably at least 95% by mass, and the upper limit is 100% by mass .

Examples of the monomer (a4) having a hydroxyl group include monomers having a hydroxyl group and a polymerizable double bond. Examples of the monomer having a hydroxyl group include: hydroxyalkyl (meth)acrylate; polyalkylene glycol (meth)acrylate, etc., preferably hydroxyalkyl (meth)acrylate.

As the monomer (a4) having a hydroxyl group, specifically, 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, ( 4-hydroxybutyl methacrylate, 6-hydroxyhexyl (meth)acrylate, 8-hydroxyoctyl (meth)acrylate and other alkyl (alkylene) with 2 to 10 carbon atoms (form base) hydroxyalkyl acrylate; polyalkylene glycol (meth)acrylate such as polyethylene glycol (meth)acrylate, etc.

The said acrylic polymer (A) may contain the unit derived from the other monomer (a5) other than the said monomer (a1) - monomer (a4). Examples of the other monomer (a5) include: pentyl (meth)acrylate, hexyl (meth)acrylate, heptyl (meth)acrylate, n-octyl (meth)acrylate, (meth)acrylate ) isooctyl acrylate, 2-ethylhexyl (meth)acrylate, nonyl (meth)acrylate, isononyl (meth)acrylate, n-decyl (meth)acrylate, iso(meth)acrylate Alkyl (meth)acrylates having an alkyl group having 5 or more carbon atoms, such as decyl ester, lauryl (meth)acrylate, stearyl (meth)acrylate, isostearyl (meth)acrylate, etc. (meth)acrylate monomers containing cyclic ethers such as glycidyl (meth)acrylate and tetrahydrofurfuryl (meth)acrylate; cyclohexyl (meth)acrylate, (meth) Alicyclic structure-containing (meth)acrylate monomers such as isobornyl acrylate; aromatic ring-containing (meth)acrylates such as phenoxyethyl (meth)acrylate and benzyl (meth)acrylate Monomer; 2-methoxyethyl (meth)acrylate, methoxybutyl (meth)acrylate, methoxypolyethylene glycol (meth)acrylate, etc. ) acrylate monomer; Vinyl acetate, vinyl propionate, vinyl butyrate, vinyl neodecanoate and other vinyl ester monomers; methyl vinyl ether, ethyl vinyl ether, propyl vinyl ether, butyrate Vinyl ether, pentyl vinyl ether, hexyl vinyl ether and other vinyl ether monomers; styrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, ethylvinylbenzene, α-methylstyrene, p-methoxystyrene, p-tert-butylstyrene, p-phenylstyrene, o-chlorostyrene, m-chlorostyrene, p-chlorostyrene, p-hydroxystyrene and other aromatics Vinyl monomer: isoprene, chloroprene, butadiene, ethylene, tetrafluoroethylene, vinylidene fluoride, etc. Among these, a (meth)acrylate monomer, a vinyl ester monomer, and a vinyl ether monomer are preferable in terms of easy adjustment of the balance of various performances, such as adhesiveness. In addition, these other monomers (a5) may be used individually, and may use 2 or more types together.

In the acrylic polymer (A), the content of the unit derived from the alkyl (meth)acrylate monomer (a1) is 45% by mass or more and less than 97% by mass, preferably 55% by mass or more , more preferably 70% by mass or more, and preferably 95% by mass or less.

In the acrylic polymer (A), the content of the unit derived from the monomer (a2) having a nitrogen atom is preferably at least 0.5% by mass, more preferably at least 1% by mass, and is preferably 30% by mass. % or less, more preferably less than 25% by mass.

In the acrylic polymer (A), the content of the unit derived from the acid group-containing monomer (a3) is preferably at least 0.5% by mass, more preferably at least 1.0% by mass, and is preferably 20% by mass. % or less, more preferably less than 15 mass %, further preferably less than 12 mass %.

The content of the unit derived from the hydroxyl group-containing monomer (a4) in the acrylic polymer (A) is preferably at least 0.01% by mass, more preferably at least 0.03% by mass, and still more preferably at least 0.05% by mass. , and preferably at most 10% by mass, more preferably at most 7% by mass, and still more preferably at most 5% by mass.

The total of the units derived from the monomer having an acid group (a3) and the monomer having a hydroxyl group (a4) is 0.5% by mass or more, preferably 1% by mass or more in the acrylic polymer (A), More preferably, it is 2 mass % or more, More preferably, it is 30 mass % or less, More preferably, it is 22 mass % or less, More preferably, it is 17 mass % or less.

In the acrylic polymer (A), it is derived from the alkyl (meth)acrylate monomer (a1), the monomer with nitrogen atom (a2), the monomer with acid group (a3) and The total of the units of the hydroxyl group-containing monomer (a4) is preferably at least 50% by mass, more preferably at least 80% by mass, still more preferably at least 90% by mass, and the upper limit is 100% by mass.

In the acrylic polymer (A), the content of units derived from another monomer (a5) is preferably at most 40% by mass, more preferably at most 30% by mass, still more preferably at most 25% by mass.

The acid value of the acrylic polymer (A) is preferably at least 5 mgKOH/g, more preferably 20 mgKOH/g, in terms of further improving the effective cohesive force when foaming is suppressed and the adhesion to the adherend. Above, and preferably below 200 mgKOH/g, more preferably below 100 mgKOH/g.

The acid value of the polymer in the present invention is a calculated value calculated from the raw material composition.

The weight average molecular weight of the acrylic polymer (A) is not less than 100,000, preferably not less than 200,000, more preferably not less than 300,000, and preferably not more than 2,000,000, more preferably not more than 1,800,000, still more preferably not more than 1,500,000.

In this specification, the number average molecular weight and weight average molecular weight of a polymer represent the conversion value measured using gel permeation chromatography (GPC) using polystyrene as a standard sample.

The glass transition temperature of the acrylic polymer (A) is -20°C or lower, preferably -60°C or higher, more preferably -50°C or higher, further preferably -50°C or higher and -25°C or lower.

The glass transition temperature Tga (K) of the acrylic polymer (A) can be calculated based on the following Fox (FOX) formula. 1/Tga=Σ(Wi/Tgi)

In the Fox (FOX) formula, Wi represents the content rate of units derived from each monomer in the acrylic polymer (A), and Tgi (K) represents a homopolymer formed only from each monomer The glass transition temperature (in absolute temperature). Details of the above-mentioned Fox (FOX) formula are described in "Bulletin of the American Physical Society, Series 2" (Vol. 1, No. 3, p. 123 (1956) )middle. In addition, the glass transition temperature (Tgi) of the homopolymer of each monomer can employ the numerical value etc. which were described in "painting and paint" (Painting Press, 10 (No. 358), 1982), for example.

The acrylic acid polymer (A) can be obtained by making the (meth)acrylic acid alkyl ester monomer (a1), the monomer (a2) with a nitrogen atom, the monomer with an acid group in the presence of a polymerization initiator The monomer (a3), the monomer (a4) which has a hydroxyl group, and other monomer (a5) used as needed are copolymerized and manufactured.

As the polymerization initiator, for example, one or two or more types of thermal polymerization initiators can be used, and examples include: peroxide initiators such as benzoyl peroxide or lauryl peroxide; azobismethylbutylene; Azo initiators such as nitrile and azobisisobutyronitrile, etc.

The adhesive composition of this invention contains a crosslinking agent (B). As the crosslinking agent, one kind or two or more kinds can be used, for example, an isocyanate crosslinking agent, an epoxy crosslinking agent, an aziridine crosslinking agent, a polyvalent metal salt crosslinking agent, a metal chelate crosslinking agent, etc. agent, ketone-hydrazide crosslinking agent, oxazoline crosslinking agent, carbodiimide crosslinking agent, silane crosslinking agent, glycidyl (alkoxy) epoxy silane crosslinking agent, etc.

Among them, preferably isocyanate crosslinking agent, epoxy crosslinking agent, metal chelate crosslinking agent, oxazoline crosslinking agent, carbodiimide crosslinking agent, more preferably isocyanate crosslinking agent, epoxy A crosslinking agent, a carbodiimide crosslinking agent, particularly preferably an epoxy crosslinking agent.

The content of the epoxy crosslinking agent in the crosslinking agent (B) is preferably at least 30% by mass, more preferably at least 50% by mass, still more preferably at least 80% by mass, still more preferably at least 90% by mass % or more, and preferably 100% by mass or less.

The acrylic polymer (C) includes: a unit derived from an alicyclic structure-containing (meth)acrylate monomer (c1); and a unit derived from an alkyl (meth)acrylate monomer (c2).

The alicyclic structure-containing (meth)acrylate monomer (c1) (hereinafter, sometimes simply referred to as "(meth)acrylate (c1)") means (meth)acrylic acid containing an alicyclic structure in its molecule. ester monomer. The alicyclic structure may be a single ring or a bridged ring, and the number of alicyclic hydrocarbon groups contained in the (meth)acrylate (c1) may be one or two or more.

Examples of the alicyclic hydrocarbon group contained in the (meth)acrylate (c1) include monocyclic alicyclic hydrocarbon groups such as cyclopentyl, cyclohexyl, and cycloheptyl; norbornyl, isobornyl, and the like; , dicyclopentyl and other bridging ring-connected alicyclic hydrocarbon groups, etc.

The number of carbon atoms of the alicyclic hydrocarbon group contained in the (meth)acrylate (c1) is 3 or more, preferably 5 or more, and preferably 20 or less, more preferably 15 or less, and more preferably 10 or less. the following.

As the alicyclic structure-containing (meth)acrylate monomer (c1) contained in the above-mentioned (meth)acrylate (c1), specifically, one or two or more types can be used, for example, (meth) Cyclopentyl acrylate, cyclohexyl (meth)acrylate, cycloheptyl (meth)acrylate and other (meth)acrylate monomers containing alicyclic structure of a single ring; norbornyl (meth)acrylate, (Meth)acrylate monomers having bridged ring-containing alicyclic structures, such as isobornyl (meth)acrylate and dicyclopentyl (meth)acrylate, etc.

The content of the unit derived from the (meth)acrylate (c1) in the acrylic polymer (C) is preferably at least 20% by mass, more preferably at least 30% by mass, further preferably at least 35% by mass Above, and preferably 95% by mass or less, more preferably 92% by mass or less, further preferably 90% by mass or less.

The alkyl (meth)acrylate monomer (c2) (hereinafter, may be simply referred to as “(meth)acrylate (c2)”) represents a (meth)acrylate monomer having an alkyl group.

Examples of the alkyl group contained in the (meth)acrylate (c2) include: methyl, ethyl, n-propyl, n-butyl, n-pentyl, n-hexyl, n-heptyl, n-octyl , n-nonyl, n-decyl, lauryl, stearyl and other linear alkyl groups; isopropyl, isobutyl, tert-butyl, isopentyl, neopentyl, isohexyl, isoheptyl, Branched chain alkyl groups such as isooctyl, 2-ethylhexyl, isononyl, isodecyl, and isostearyl, etc.

The number of carbon atoms of the alkyl group contained in the (meth)acrylate (c2) is preferably 1 or more, and is preferably 20 or less, more preferably 15 or less, and still more preferably 12 or less.

As the (meth)acrylate (c2), one or more kinds can be used, for example, methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, ( n-butyl methacrylate, isobutyl (meth)acrylate, tert-butyl (meth)acrylate, amyl (meth)acrylate, hexyl (meth)acrylate, n-octyl (meth)acrylate ester, isooctyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, nonyl (meth)acrylate, isononyl (meth)acrylate, n-decyl (meth)acrylate, ( Isodecyl meth)acrylate, lauryl (meth)acrylate, stearyl (meth)acrylate, isostearyl (meth)acrylate, etc.

The content of units derived from the (meth)acrylate (c2) in the acrylic polymer (C) is preferably at least 1% by mass, more preferably at least 5% by mass, further preferably at least 7% by mass above, and preferably at most 80% by mass, more preferably at most 70% by mass, and still more preferably at most 60% by mass.

The content ratio ((c1)/(c2)) of the unit derived from the (meth)acrylate (c1) to the unit derived from the (meth)acrylate (c2) is based on mass, compared to Preferably at least 0.1, more preferably at least 0.5, still more preferably at least 0.7, more preferably at most 20, more preferably at most 15, still more preferably at most 12.

The acrylic polymer (C) includes units derived from the alicyclic structure-containing (meth)acrylate monomer (c1) and the (meth)alkyl (meth)acrylate monomer (c2), Units derived from other monomers (c3) may also be contained.

Examples of the other monomer (c3) include monomers having an acid group, monomers having a hydroxyl group, monomers having a nitrogen atom, monomers having a cyclic ether, monomers having an aromatic ring, monomers having a ring Monomers with oxane structure, etc.

The content of the other monomer (c3) in the acrylic polymer (C) is preferably at most 20% by mass, more preferably at most 15% by mass, still more preferably at most 12% by mass, and the lower limit is 0% by mass .

The glass transition temperature of the acrylic polymer (C) is above 50°C, preferably above 55°C, more preferably above 60°C, preferably below 120°C, more preferably below 110°C.

The glass transition temperature Tga (K) of the said acrylic polymer (C) can be calculated based on Fox (FOX) formula similarly to the said acrylic polymer (A).

The weight average molecular weight of the acrylic polymer (C) is less than 100,000, preferably less than 80,000, more preferably less than 60,000, preferably more than 1,000, more preferably more than 1,500, and more preferably more than 2,500.

The acrylic polymer (C) can be obtained by making the alicyclic structure-containing (meth)acrylate monomer (c1), (meth)acrylate alkyl monomer ( c2) and other monomers (c3) used as needed are copolymerized and produced.

As the polymerization initiator, for example, one or two or more types of thermal polymerization initiators can be used, and examples include: peroxide initiators such as benzoyl peroxide or lauryl peroxide; azobismethylbutylene; Azo initiators such as nitrile and azobisisobutyronitrile, etc.

In the adhesive composition of the present invention, the content of the acrylic polymer (A) in the non-volatile components is preferably at least 15% by mass, more preferably at least 20% by mass, still more preferably at least 25% by mass, And it is preferably 99% by mass or less.

In this specification, the term "non-volatile components of the adhesive composition" refers to the part after removing the solvent component contained in the adhesive composition if necessary.

In the adhesive composition of the present invention, the content of the crosslinking agent (B) is preferably at least 0.01 parts by mass, more preferably at least 0.05 parts by mass, relative to 100 parts by mass of the acrylic polymer (A), More preferably, it is 0.1 mass parts or more, More preferably, it is 5 mass parts or less, More preferably, it is 3 mass parts or less, More preferably, it is 2 mass parts or less.

In the adhesive composition of the present invention, the content of the acrylic polymer (C) in the non-volatile components is preferably at least 0.1% by mass, more preferably at least 0.5% by mass, and still more preferably at least 1% by mass. And it is preferably at most 40 mass %, more preferably at most 30 mass %, and still more preferably at most 25 mass %.

In the adhesive composition of the present invention, the content of the acrylic polymer (C) is preferably at least 0.1 parts by mass, more preferably at least 0.5 parts by mass, based on 100 parts by mass of the acrylic polymer (A). More preferably, it is 1 mass part or more, More preferably, it is 60 mass parts or less, More preferably, it is 30 mass parts or less, More preferably, it is 25 mass parts or less.

The adhesive composition of the present invention preferably contains a solvent (D). As the solvent (D), one kind or two or more kinds can be used, for example: aromatic hydrocarbon solvents such as toluene and xylene; ester solvents such as ethyl acetate and butyl acetate; ketones such as acetone and methyl ethyl ketone Solvents; aliphatic hydrocarbon solvents such as hexane, etc. Among them, it is preferable to include an ester solvent.

The content of the ester solvent in the solvent (D) is preferably at least 30% by mass, more preferably at least 50% by mass, still more preferably at least 70% by mass, and more preferably at most 100% by mass.

The content of the solvent (D) in the adhesive composition is preferably at least 10% by mass, more preferably at least 30% by mass, still more preferably at least 50% by mass, and more preferably at most 90% by mass, More preferably, it is 70 mass % or less, More preferably, it is 65 mass % or less.

In the adhesive composition of the present invention, in order to maintain low yellowing, it is preferable to reduce the content of the tackifying resin, preferably less than 10 parts by mass, more preferably 8 parts by mass relative to 100 parts by mass of the acrylic polymer. Part or less, more preferably 3 parts by mass or less, still more preferably 1 part by mass or less, and preferably 0 part by mass.

The adhesive composition of the present invention may also contain alkali (ammonia water, etc.) or acid for adjusting pH; foaming agent; plasticizer; softener; antioxidant; fiber-balloon-bead- made of glass or plastic Fillers such as metal powders; coloring agents such as pigments and dyes; pH regulators; film formation auxiliary agents; leveling agents; thickeners; hydrophobic agents; defoamers; acid catalysts; acid generators, etc.

An adhesive layer can be formed by applying the adhesive composition on a support and drying it. The support body may be any one of substrates such as release sheets and adhesive sheets.

As the coating method, a method such as a knife coater, a reverse coater, a die coater, a lip die coater, a slot die coater, a gravure coater, or a curtain coater can be used. .

The thickness of the adhesive layer is preferably 5 μm or more, more preferably 10 μm or more, further preferably 15 μm or more, and preferably 150 μm or less, more preferably 100 μm or less, further preferably 75 μm or less.

The adhesive sheet or adhesive tape of this invention has the said adhesive layer and the said base material. The base material can be in any shape such as film, sheet, strip, plate, three-dimensional shape, etc. As the material of the base material, polyester resin, polypropylene resin, polyethylene resin, polyamide resin, etc. Amine resin, vinyl chloride resin, urethane resin and other plastics; rubber; non-woven fabric; metal foil; paper, etc., preferably plastic, more preferably polyester resin, thermoplastic urethane resin. In addition, the base material may be a base material with a smooth surface, or a base material with irregularities on the surface, such as a fibrous base material or a foam base material.

The thickness of the base material is preferably 0.1 μm or more, and preferably 1,000 μm or less. [Example]

The following specific examples are given to illustrate the present invention in more detail. In addition, the weight average molecular weight (Mw) of the resin of this invention is measured on the following GPC measurement conditions.

[GPC measurement conditions] Measuring device: High-speed GPC device ("HLC-8220GPC" manufactured by Tosoh Co., Ltd.) Pipe string: The following pipe string manufactured by Tosoh Co., Ltd. was connected in series and used. "TSKgel G5000" (7.8 mmI.D.×30 cm)×1 piece "TSKgel G4000" (7.8 mmI.D.×30 cm)×1 piece "TSKgel G3000" (7.8 mmI.D.×30 cm)×1 piece "TSKgel G2000" (7.8 mmI.D.×30 cm)×1 Detector: RI (Differential Refractometer) Column temperature: 40°C Eluent: tetrahydrofuran (tetrahydrofuran, THF) Flow rate: 1.0 mL/min Injection volume: 100 μL (tetrahydrofuran solution with a sample concentration of 4 mg/mL) Standard sample: A calibration curve was prepared using the following monodisperse polystyrene.

(monodisperse polystyrene) "TSKgel Standard Polystyrene A-500" manufactured by Tosoh Co., Ltd. "TSKgel Standard Polystyrene A-1000" manufactured by Tosoh Co., Ltd. "TSKgel Standard Polystyrene A-2500" manufactured by Tosoh Co., Ltd. "TSKgel Standard Polystyrene A-5000" manufactured by Tosoh Co., Ltd. "TSKgel Standard Polystyrene F-1" manufactured by Tosoh Co., Ltd. "TSKgel Standard Polystyrene F-2" manufactured by Tosoh Co., Ltd. "TSKgel Standard Polystyrene F-4" manufactured by Tosoh Co., Ltd. "TSKgel Standard Polystyrene F-10" manufactured by Tosoh Co., Ltd. "TSKgel Standard Polystyrene F-20" manufactured by Tosoh Co., Ltd. "TSKgel Standard Polystyrene F-40" manufactured by Tosoh Co., Ltd. "TSKgel Standard Polystyrene F-80" manufactured by Tosoh Co., Ltd. "TSKgel Standard Polystyrene F-128" manufactured by Tosoh Co., Ltd. "TSKgel Standard Polystyrene F-288" manufactured by Tosoh Co., Ltd. "TSKgel Standard Polystyrene F-550" manufactured by Tosoh Co., Ltd.

(Synthesis Example 1: Synthesis of Acrylic Polymer (A-1)) 590 parts by mass of butyl acrylate (hereinafter referred to as "BA") and 345 parts by mass of methyl acrylate (hereinafter referred to as "MA") were placed in a reaction vessel including a stirrer, a reflux cooling pipe, a nitrogen gas introduction pipe, and a thermometer. 50 parts by mass of diethylacrylamide (hereinafter referred to as "DEAA"), 10 parts by mass of acrylic acid (hereinafter referred to as "AA"), 4-hydroxybutyl acrylate (hereinafter referred to as "4HBA") 5 parts by mass and 1000 parts by mass of ethyl acetate were heated up to 72° C. while blowing nitrogen gas under stirring. After 1 hour, 10 parts by mass of a 2,2'-azobis(2-methylbutyronitrile) solution previously dissolved in ethyl acetate was added (0.5 mass % of solid content). Then, after holding at 72 degreeC with stirring for 8 hours, the content was cooled, and it filtered with the 200-mesh metal mesh, and obtained the 50 mass % solution of an acrylic acid polymer (A-1).

(Synthesis Example 2: Synthesis of Acrylic Polymer (A-2)) 250 parts by mass of 2-ethylhexyl acrylic acid (hereinafter referred to as "2EHA"), 509 parts by mass of BA, dimethylacrylamide, and (hereinafter referred to as "DMAA") 25 parts by mass, AA 215 parts by mass, 2-hydroxyethyl acrylate (hereinafter referred to as "HEA") 1 part by mass, ethyl acetate 950 parts by mass, while stirring The temperature was raised to 65°C under nitrogen. After 1 hour, 10 parts by mass of a 2,2'-azobis(2-methylbutyronitrile) solution previously dissolved in ethyl acetate was added (0.5 mass % of solid content). Thereafter, after holding at 65° C. for 10 hours with stirring, the contents were cooled, 50 parts by mass of ethyl acetate was charged, and filtered through a 200-mesh metal mesh to obtain 50 mass % of the acrylic polymer (A-2). solution.

(Synthesis Example 3: Synthesis of Acrylic Polymer (A-3)) Except having changed the monomer composition as shown in Table 1, it carried out similarly to the synthesis example 2, and obtained the 50 mass % solution of an acrylic acid polymer (A-3).

(Synthesis Example 4 to Synthesis Example 6: Synthesis of Acrylic Polymer (A-4) to Acrylic Polymer (A-6)) Except having changed the monomer composition as shown in Table 1, it carried out similarly to the synthesis example 1, and obtained the 50 mass % solution of an acrylic polymer (A-4) - an acrylic polymer (A-6).

(Synthesis Example 7: Synthesis of Acrylic Polymer (A-7)) In the reaction vessel comprising a stirrer, a reflux cooling pipe, a nitrogen inlet pipe, and a thermometer, 350 parts by mass of 2EHA, 482 parts by mass of BA, 385 parts by mass of MA, 100 parts by mass of DEAA, 3 parts by mass of 4HBA, and 900 parts by mass of ethyl acetate were charged portion, and the temperature was raised to 65° C. while blowing nitrogen gas under stirring. After 1 hour, 10 parts by mass of a 2,2'-azobis(2-methylbutyronitrile) solution previously dissolved in ethyl acetate was added (0.5 mass % of solid content). Thereafter, after holding at 65° C. for 10 hours with stirring, the contents were cooled, 100 parts by mass of ethyl acetate was charged, and filtered through a 200-mesh metal mesh to obtain 50 mass % of the acrylic polymer (A-7). solution.

(Synthesis Example 8 to Synthesis Example 9: Synthesis of Acrylic Polymer (A-8) to Acrylic Polymer (A-9)) Except having changed the monomer composition as shown in Table 2, it carried out similarly to the synthesis example 1, and obtained the 50 mass % solution of acrylic polymer (A-8) - acrylic polymer (A-9).

(Synthesis Example 10: Synthesis of Acrylic Polymer (A-10)) Except having changed the monomer composition as shown in Table 2, it carried out similarly to the synthesis example 3, and obtained the 50 mass % solution of an acrylic acid polymer (A-10).

(Synthesis Example 11: Synthesis of Acrylic Polymer (C-1)) 75 parts by mass of methyl ethyl ketone (hereinafter, abbreviated as "MEK") was placed in a reaction vessel including a stirrer, a thermometer, a dropping funnel, a cooling pipe, and a nitrogen inlet, and the temperature was raised to 80°C. Then, at the same temperature, 78 parts by mass of cyclohexyl methacrylate (hereinafter, abbreviated as "CHMA"), methyl methacrylate (hereinafter, abbreviated as "MMA") were added dropwise to the reaction vessel over 4 hours. ") 20 parts by mass, methacrylic acid (hereinafter, abbreviated as "MAA") 2 parts by mass, MEK 6.8 parts by mass, and tertiary butyl peroxy-2-ethylhexanoate (hereinafter, abbreviated as "TBPEH") 5.5 The mixture in parts by mass was further reacted at the same temperature for 12 hours after completion of the dropwise addition to obtain a 55% by mass solution of the acrylic acid polymer (C-1).

(Synthesis Example 12 to Synthesis Example 14: Synthesis of Acrylic Polymer (C-2) to Acrylic Polymer (C-4)) Except having changed the monomer composition as shown in Table 3, it carried out similarly to the synthesis example 11, and obtained the 55 mass % solution of an acrylic polymer (C-2) - an acrylic polymer (C-4).

(Synthesis Example 15: Synthesis of Acrylic Polymer (C-5)) 75 parts by mass of methyl ethyl ketone (hereinafter, abbreviated as "MEK") was placed in a reaction vessel including a stirrer, a thermometer, a dropping funnel, a cooling pipe, and a nitrogen inlet, and the temperature was raised to 80°C. Then, at the same temperature, 4 parts by mass of 2-ethylhexyl methacrylate (hereinafter referred to as "2EHMA") containing 10 parts by mass of CHMA, 76 parts by mass of MMA, and 4 parts by mass of CHMA were added dropwise to the reaction vessel over 4 hours. , 9 parts by mass of MAA, 1 part by mass of 2EHA, 6.8 parts by mass of MEK, and 3 parts by mass of TBPEH, after the dropwise addition, reacted at the same temperature for 12 hours to obtain 55% by mass of the acrylic acid polymer (C-1) solution.

(Synthesis Example 16 to Synthesis Example 20: Synthesis of Acrylic Polymer (C-6) to Acrylic Polymer (C-10)) Except having changed the monomer composition as shown in Table 3, it carried out similarly to the synthesis example 11, and obtained the 55 mass % solution of acrylic polymer (C-6) - acrylic polymer (C-10).

[Table 1] Table 1 Synthesis Example 1 Synthesis example 2 Synthesis example 3 Synthesis Example 4 Synthesis Example 5 Acrylic polymer (A) (A-1) (A-2) (A-3) (A-4) (A-5) Monomer composition (parts by mass) (a1) 2EHA 25 5 BA 59 50.9 61.5 60 78 EA 25 MA 34.5 14 (a5) CHA 5.5 (a2) DEAA 5 DMAA 2.5 1.5 NIPAM 2.5 DAAM twenty two (a3) AAA 1 21.5 5 9.5 6 (a4) 4HBA 0.5 3 HEA 0.1 1 0.5 Weight average molecular weight 221000 562000 417000 285000 313000 Glass transition temperature (°C) -32 -35 -40 -twenty two -41

[Table 2] Table 2 Synthesis Example 6 Synthesis Example 7 Synthesis Example 8 Synthesis Example 9 Synthesis Example 10 Acrylic polymer (A) (A-6) (A-7) (A-8) (A-9) (A-10) Monomer composition (parts by mass) (a1) 2EHA 35 64 BA 73.5 48.2 59 20 44.5 EA 4.5 MA 6.5 38.5 38 (a5) CHA 2.5 IBXA 10 (a2) DEAA 10 DMAA 4 11 DAAM 15 (a3) AAA 2 1 6 (a4) 4HBA 0.3 0.5 HEA 4.5 1 0.5 Weight average molecular weight 364000 816000 264000 350000 720000 Glass transition temperature (°C) -38 -49 -34 -51 -15

[table 3] table 3 Synthesis Example 11 Synthesis Example 12 Synthesis Example 13 Synthesis Example 14 Synthesis Example 15 Acrylic polymer (C) (C-1) (C-2) (C-3) (C-4) (C-5) Monomer composition (parts by mass) (c1) CHMA 78 40 58 82 10 DCP 76 (c2) MMA 20 35 EMA 30 BMA 7 2EHMA 4 (c3) MAA 2 30 7 11 9 2EHA 1 Weight average molecular weight 19500 25300 21700 22100 35900 Glass transition temperature (°C) 74 86 83 69 143

[Table 4] Table 4 Synthesis Example 16 Synthesis Example 17 Synthesis Example 18 Synthesis Example 19 Synthesis Example 20 Acrylic polymer (C) (C-6) (C-7) (C-8) (C-9) (C-10) Monomer composition (parts by mass) (c1) CHMA 30 85 55 IBXMA 55 50 (c2) MMA 37 64 15 40 BMA 50 (c3) MAA 5 AAA 8 HEMA 1 5 Weight average molecular weight 18900 21700 30200 19800 17500 Glass transition temperature (°C) 108 93 71 59 80

In Tables 1 to 4, each abbreviation represents the following compounds, respectively. 2EHA: 2-Ethylhexyl Acrylate BA: n-butyl acrylate EA: ethyl acrylate MA: methyl acrylate CHA: cyclohexyl acrylate DEAA: N,N-Diethylacrylamide DMAA: N,N-Dimethacrylamide NIPAM: N,N-Diisopropylacrylamide DAAM: diacetone acrylamide AA: Acrylic 4HBA: 4-Hydroxybutyl Acrylate HEA: 2-Hydroxyethyl Acrylate IBXA: Isobornyl Acrylate CHMA: Cyclohexyl methacrylate DCP: dicyclopentyl methacrylate MMA: methyl methacrylate EMA: ethyl methacrylate BMA: n-butyl methacrylate 2EHMA: 2-Ethylhexyl methacrylate MAA: methacrylic acid IBXMA: Isobornyl Methacrylate HEMA: 2-Hydroxyethyl methacrylate

(Example 1: Preparation and Evaluation of Adhesive Composition (1)) With respect to 100 parts by mass of the 50% by mass solution of the acrylic polymer (A-1) obtained in Synthesis Example 1, 55% of the acrylic polymer (C-1) obtained in Synthesis Example 4 was uniformly adjusted. 10 parts by mass of solution, 0.05 parts by mass of epoxy-based crosslinking agent ("TETRAD X" manufactured by Mitsubishi Gas Chemical Co., Ltd.; hereinafter referred to as "crosslinking agent (B-1)") Stirring and mixing are performed to obtain an adhesive composition (1).

[processing method 1 of the adhesive film] On the surface of a polyethylene terephthalate film (release PET50) with a thickness of 50 μm that has been subjected to mold release treatment, apply the adhesive obtained in the example so that the film thickness after solvent drying is 25 μm The composition was evaporated in a dryer at 80°C for 3 minutes, and then laminated to a polyethylene terephthalate film (PET50) with a thickness of 50 μm.

[processing method 2 of the adhesive film] On the surface of a polyethylene terephthalate film (release PET50) with a thickness of 50 μm that has undergone mold release treatment, apply the adhesive obtained in the example so that the film thickness after solvent drying is 50 μm For the composition, the solvent was volatilized in a dryer at 80°C for 3 minutes, and then laminated with release PET50.

[Evaluation of initial optical properties 1] The adhesive film produced by the said method 2 was stuck on a glass plate, and what was obtained in this way was made into the test piece. The release PET film of the test piece was peeled off, and the structure of the adhesive layer and the glass plate was made, and the turbidimeter "NDH5000" (manufactured by Nippon Denshoku Industries Co., Ltd.) was used to measure the temperature according to the Japanese Industrial Standards (JIS). ) K 7361-1 Determination of haze. In addition, the initial haze of glass alone was 0.2.

[Evaluation of initial optical properties 2] After attaching the adhesive film produced by the method 2 above to the glass adherend, it was press-bonded at a temperature of 50° C. and an air pressure of 0.5 MPa for 20 minutes, and this was used as a test piece. The release PET film of the test piece was peeled off to form an adhesive layer and a glass plate, and the light source C, field of view 2°, "spectrocolorimeter" CM-5000d (Konica Minolta Sensing (Konica Minolta Sensing) Sensing Co., Ltd.), the initial color number (b*) was measured in accordance with JIS K 7105. In addition, the initial color number (b*) of glass alone was 0.1.

[Evaluation of Moisture and Heat Resistance Optical Properties] After attaching the adhesive film made by the above-mentioned method 2 to the glass adherend, press it at a temperature of 50°C and an air pressure of 0.5 MPa for 20 minutes, and let it stand for 500 hours in an environment of 85°C and 85%RH. The obtained one was set as a test piece, and the color number (b*) and the haze were measured for this test piece in the same manner as the method described above.

[Evaluation of foaming resistance] The adhesive film produced by said method 1 was cut into width 50 mm, and length 50 mm, and what was obtained in this way was set as a test piece. Glass, acrylic board, and polycarbonate board (PC board) with a thickness of 2 mm were used as the adherend. After being attached to the adherend, press at a temperature of 50°C and an air pressure of 0.5 MPa for 20 minutes. After that, it was left still for a predetermined time under each durability test environment (1) to durability test environment (3), and the appearance immediately after taking it out was evaluated by the following criteria. Endurance test environment (1) 2 hours at 100°C Endurance test environment (2) 24 hours at 85°C and 85%RH Endurance test environment (3) immersion in warm water at 80°C for 2 hours 〇: There is no change before and after the durability test, △: Surface unevenness occurs, ×: Blistering and whitening occur

[Evaluation of initial adhesion] The adhesive film produced by the said method 1 was cut into 25 mm width, and what thus obtained was set as a test piece. The adherend is set as a polycarbonate plate or a glass plate, and it is attached to the adherend with a 2 kg roller x 2 times. After 2 hours of sticking, measure the 180-degree peel strength at 23°C and 50% RH atmosphere, and set it as the adhesive force (N/25 mm).

[Evaluation of Humidity and Heat Resistance Adhesion] The adhesive film produced by the said method 1 was cut into 25 mm width, and what thus obtained was made into the test piece. The adherend is set as a polycarbonate plate or a glass plate, and it is attached to the adherend with a 2 kg roller x 2 times. After attaching for 30 minutes, let it stand for 500 hours at 85°C and 85%RH. After taking it out, let it stand to cool at room temperature, measure the 180-degree peel strength in an atmosphere of 23°C and 50%RH, and set it as the adhesive force (N/25 mm).

[Evaluation of heat-resistant water adhesion] The adhesive film produced by the said method 1 was cut into 25 mm width, and what thus obtained was made into the test piece. The adherend is set as a polycarbonate plate or a glass plate, and it is attached to the adherend with a 2 kg roller x 2 times. After sticking for 30 minutes, soak in warm water at 80°C for 2 hours. After taking it out from the warm water, wipe off the water, measure the 180-degree peel strength in an atmosphere of 23°C and 50%RH, and set it as the adhesive force (N/25 mm).

(Example 2-Example 19: Preparation and Evaluation of Adhesive Composition (2)-Adhesive Composition (19)) Except that the acrylic polymer (A-1), crosslinking agent (B-1), and acrylic polymer (C-1) used in Example 1 were changed as shown in Tables 5 to 7, the same as in Example 1 Adhesive composition ( 2 ) to adhesive composition ( 19 ) were similarly obtained, and various evaluations were performed thereafter.

(Comparative Example 1 to Comparative Example 4: Preparation and Evaluation of Adhesive Composition (R1) to Adhesive Composition (R4)) Obtained in the same manner as in Example 1, except that the acrylic polymer (A-1), crosslinking agent (B-1), and acrylic polymer (C-1) used in Example 1 were changed as shown in Table 8. Adhesive composition (R1) to adhesive composition (R4), and then various evaluations were performed.

[table 5] table 5 Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 adhesive composition (1) (2) (3) (4) (5) (6) Composition (parts by mass) 50% by mass solution of acrylic polymer (A) A-1 A-1 A-1 A-1 A-1 A-2 100 100 100 100 100 100 Cross-linking agent (B) B-1 B-3 B-4 B-1 B-1 B-2 0.05 1.5 0.8 0.05 0.04 0.05 55% by mass solution of acrylic acid polymer (C) C-1 C-1 C-1 C-1 C-8 C-2 10 10 10 30 10 5 Evaluation results Initial Optical Properties Haze (%) 0.4 0.4 0.4 0.9 0.5 0.9 Chromatic number (b*) 0.1 0.2 0.1 0.2 0.1 0.3 Moisture and heat resistance optical properties Haze (%) 0.4 1.1 0.4 0.9 0.6 1.1 Chromatic number (b*) 0.2 2.1 0.2 0.3 0.2 0.9 Foam resistance Test environment (1) PC board 〇 〇 〇 〇 〇 〇 Test environment (2) PC board 〇 〇 〇 〇 〇 〇 Test environment (3) PC board 〇 〇 〇 〇 〇 〇 Test environment (3) glass plate 〇 〇 〇 〇 〇 〇 Test environment (3) Acrylic board 〇 〇 〇 〇 〇 〇 Initial adhesion force (N/25 mm) PC board 20 twenty two 20 11 18 twenty two glass plate 20 twenty one 20 14 19 twenty one Resistance to heat and humidity (N/25 mm) PC board 28 31 26 25 twenty four 15 glass plate 27 27 29 25 26 14 Warm water resistance (N/25 mm) PC board 20 19 twenty one 14 18 7

[Table 6] Table 6 Example 7 Example 8 Example 9 Example 10 Example 11 Example 12 adhesive composition (7) (8) (9) (10) (11) (12) Composition (parts by mass) 50% by mass solution of acrylic polymer (A) A-3 A-3 A-3 A-4 A-4 A-5 100 100 100 100 100 100 Cross-linking agent (B) B-1 B-1 B-1 B-1 B-1 B-1 0.05 0.05 0.15 0.25 0.1 0.05 55% by mass solution of acrylic acid polymer (C) C-3 C-6 C-7 C-4 C-5 C-3 10 10 10 10 2 10 Evaluation results Initial Optical Properties Haze (%) 0.5 0.7 0.5 0.5 0.6 0.5 Chromatic number (b*) 0.1 0.2 0.1 0.2 0.1 0.1 Moisture and heat resistance optical properties Haze (%) 0.5 0.7 0.5 0.5 0.6 0.5 Chromatic number (b*) 0.2 0.3 0.2 0.3 0.2 0.2 Foam resistance Test environment (1) PC board 〇 〇 〇 〇 〇 〇 Test environment (2) PC board 〇 〇 〇 〇 〇 〇 Test environment (3) PC board 〇 〇 〇 〇 〇 〇 Test environment (3) glass plate 〇 〇 〇 〇 〇 〇 Test environment (3) Acrylic board 〇 〇 〇 〇 〇 〇 Initial adhesion force (N/25 mm) PC board 20 20 19 13 14 18 glass plate twenty one 19 20 15 16 20 Resistance to heat and humidity (N/25 mm) PC board 27 27 twenty four 16 28 25 glass plate 28 26 twenty three 19 26 27 Warm water resistance (N/25 mm) PC board twenty two 20 20 15 19 18

[Table 7] Table 7 Example 13 Example 14 Example 15 Example 16 Example 17 Example 18 Example 19 adhesive composition (13) (14) (15) (16) (17) (18) (19) Composition (parts by mass) 50% by mass solution of acrylic polymer (A) A-5 A-5 A-6 A-6 A-6 A-6 A-7 100 100 100 100 100 100 100 Cross-linking agent (B) B-1 B-1 B-5 B-4 B-4 B-4 B-4 0.05 0.05 0.1 1.5 1.5 1.5 1.5 55% by mass solution of acrylic acid polymer (C) C-6 C-7 C-1 C-8 C-9 C-10 C-10 5 10 10 15 20 5 40 Evaluation results Initial Optical Properties Haze (%) 0.6 0.5 0.7 0.4 0.5 0.4 0.9 Chromatic number (b*) 0.2 0.1 0.1 0.1 0.1 0.1 0.2 Moisture and heat resistance optical properties Haze (%) 0.6 0.5 0.8 0.4 0.5 0.5 0.9 Chromatic number (b*) 0.3 0.2 0.2 0.2 0.1 0.1 0.2 Foam resistance Test environment (1) PC board 〇 〇 〇 〇 〇 〇 〇 Test environment (2) PC board 〇 〇 〇 〇 〇 〇 〇 Test environment (3) PC board 〇 〇 〇 △ △ △ 〇 Test environment (3) glass plate 〇 〇 〇 〇 〇 〇 〇 Test environment (3) Acrylic board 〇 〇 〇 〇 〇 〇 〇 Initial adhesion force (N/25 mm) PC board twenty one 18 19 18 16 18 12 glass plate 20 20 20 17 16 20 13 Resistance to heat and humidity (N/25 mm) PC board 28 25 twenty two twenty one 20 twenty one 19 glass plate twenty four 27 twenty three twenty two twenty one twenty three 20 Warm water resistance (N/25 mm) PC board 20 19 20 17 18 19 14

[Table 8] Table 8 Comparative example 1 Comparative example 2 Comparative example 3 Comparative example 4 adhesive composition (R1) (R2) (R3) (R4) Composition (parts by mass) 50% by mass solution of acrylic polymer (A) A-1 A-8 A-9 A-10 100 100 100 100 Cross-linking agent (B) B-1 B-5 B-4 B-5 0.05 0.1 1.5 0.1 55% by mass solution of acrylic acid polymer (C) C-1 C-1 C-3 10 10 20 Evaluation results Initial Optical Properties Haze (%) 0.4 0.5 0.5 0.4 Chromatic number (b*) 0.2 0.2 0.1 0.1 Moisture and heat resistance optical properties Haze (%) 0.4 0.6 0.5 0.5 Chromatic number (b*) 0.2 0.3 0.1 0.1 Foam resistance Test environment (1) PC board x 〇 〇 x Test environment (2) PC board x △ x x Test environment (3) PC board x x x x Test environment (3) glass plate 〇 〇 〇 〇 Test environment (3) Acrylic board △ 〇 〇 x Initial adhesion force (N/25 mm) PC board 17 19 16 3 glass plate 15 20 16 7 Resistance to heat and humidity (N/25 mm) PC board 26 twenty two 20 twenty one glass plate twenty four twenty three twenty one twenty three Warm water resistance (N/25 mm) PC board 16 20 18 19

In Tables 5 to 8, each abbreviation represents the following compounds, respectively. Crosslinking agent (B-1): Tetrad (TETRAD) X (epoxy-based crosslinking agent: manufactured by Mitsubishi Gas Chemical Co., Ltd.) Cross-linking agent (B-2): Tetrad (TETRAD) C (epoxy-based cross-linking agent: manufactured by Mitsubishi Gas Chemical Co., Ltd.) Cross-linking agent (B-3): Barnock (BURNOCK) D-750 (isocyanate-based cross-linking agent: manufactured by DIC Co., Ltd.) Cross-linking agent (B-4): TAKENATE D-110N (isocyanate-based cross-linking agent: manufactured by Mitsui Chemicals Co., Ltd.) Cross-linking agent (B-5): Barnock (BURNOCK) DN-980 (isocyanate-based cross-linking agent: manufactured by DIC Co., Ltd.)

It was confirmed that the adhesive films obtained from Examples 1 to 19, which are the adhesive composition of the present invention, have optical transparency, foaming resistance, and adhesive properties even in high-temperature and high-humidity environments or in high-temperature and warm-water immersion environments. Strength is also excellent.

Comparative Example 1 is an example that does not contain an acrylic polymer (C), and has poor foaming resistance in a high-temperature and high-humidity environment or in a high-temperature warm water immersion environment.

Comparative Example 2 is an example in which an acrylic polymer not containing a monomer (a2) having a nitrogen atom is used instead of the acrylic polymer (A), and has poor foaming resistance in a high-temperature warm water immersion environment.

In Comparative Example 3, an acrylic polymer having a content rate of less than 50% by mass of units derived from an alkyl (meth)acrylate monomer (a1) having an alkyl group having 1 to 4 carbon atoms was used instead of the acrylic polymer (A ) examples, poor foaming resistance in high temperature and high humidity environment or high temperature warm water immersion environment.

Comparative Example 4 is an example of using an acrylic polymer with a glass transition temperature higher than -20°C instead of the acrylic polymer (A), and its foaming resistance and adhesive force are poor in high temperature and high humidity environment or high temperature warm water immersion environment.

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Claims (4)

An adhesive composition, characterized by comprising: an acrylic polymer (A), a crosslinking agent (B) and an acrylic polymer (C), The acrylic polymer (A) includes: a unit derived from an alkyl (meth)acrylate monomer (a1) having an alkyl group having 1 to 4 carbon atoms; a unit derived from a monomer (a2) having a nitrogen atom and a unit derived from at least one selected from the group consisting of a monomer (a3) having an acid group and a monomer (a4) having a hydroxyl group, The glass transition temperature of the acrylic polymer (A) is below -20°C, The weight average molecular weight of the acrylic polymer (A) is 100,000 or more, The content rate of the unit derived from the alkyl (meth)acrylate monomer (a1) having an alkyl group having 1 to 4 carbon atoms is 50% by mass or more and less than 50% by mass in the acrylic polymer (A). 97% by mass, The acrylic polymer (C) comprises: a unit derived from an alicyclic structure-containing (meth)acrylate monomer (c1); and a unit derived from an alkyl (meth)acrylate monomer (c2), The glass transition temperature of the acrylic polymer (C) is above 50°C, The weight average molecular weight of the acrylic polymer (C) is less than 100,000. The adhesive composition according to claim 1, wherein the content of the unit derived from the monomer (a2) having a nitrogen atom is 0.5% by mass or more and less than 30% by mass in the acrylic polymer (A) %. An adhesive layer is formed by the adhesive composition as described in Claim 1 or Claim 2. An adhesive film having the adhesive layer described in Claim 3.