CN108690536B - Adhesive composition and adhesive sheet - Google Patents
Adhesive composition and adhesive sheet Download PDFInfo
- Publication number
- CN108690536B CN108690536B CN201810300180.3A CN201810300180A CN108690536B CN 108690536 B CN108690536 B CN 108690536B CN 201810300180 A CN201810300180 A CN 201810300180A CN 108690536 B CN108690536 B CN 108690536B
- Authority
- CN
- China
- Prior art keywords
- meth
- mass
- parts
- acrylate
- acrylic copolymer
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
Classifications
-
- C—CHEMISTRY; METALLURGY
- C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
- C09J—ADHESIVES; NON-MECHANICAL ASPECTS OF ADHESIVE PROCESSES IN GENERAL; ADHESIVE PROCESSES NOT PROVIDED FOR ELSEWHERE; USE OF MATERIALS AS ADHESIVES
- C09J133/00—Adhesives based on homopolymers or copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and at least one being terminated by only one carboxyl radical, or of salts, anhydrides, esters, amides, imides, or nitriles thereof; Adhesives based on derivatives of such polymers
- C09J133/04—Homopolymers or copolymers of esters
- C09J133/06—Homopolymers or copolymers of esters of esters containing only carbon, hydrogen and oxygen, the oxygen atom being present only as part of the carboxyl radical
- C09J133/08—Homopolymers or copolymers of acrylic acid esters
-
- C—CHEMISTRY; METALLURGY
- C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
- C09J—ADHESIVES; NON-MECHANICAL ASPECTS OF ADHESIVE PROCESSES IN GENERAL; ADHESIVE PROCESSES NOT PROVIDED FOR ELSEWHERE; USE OF MATERIALS AS ADHESIVES
- C09J11/00—Features of adhesives not provided for in group C09J9/00, e.g. additives
- C09J11/08—Macromolecular additives
-
- C—CHEMISTRY; METALLURGY
- C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
- C09J—ADHESIVES; NON-MECHANICAL ASPECTS OF ADHESIVE PROCESSES IN GENERAL; ADHESIVE PROCESSES NOT PROVIDED FOR ELSEWHERE; USE OF MATERIALS AS ADHESIVES
- C09J133/00—Adhesives based on homopolymers or copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and at least one being terminated by only one carboxyl radical, or of salts, anhydrides, esters, amides, imides, or nitriles thereof; Adhesives based on derivatives of such polymers
- C09J133/04—Homopolymers or copolymers of esters
- C09J133/06—Homopolymers or copolymers of esters of esters containing only carbon, hydrogen and oxygen, the oxygen atom being present only as part of the carboxyl radical
- C09J133/10—Homopolymers or copolymers of methacrylic acid esters
-
- C—CHEMISTRY; METALLURGY
- C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
- C09J—ADHESIVES; NON-MECHANICAL ASPECTS OF ADHESIVE PROCESSES IN GENERAL; ADHESIVE PROCESSES NOT PROVIDED FOR ELSEWHERE; USE OF MATERIALS AS ADHESIVES
- C09J7/00—Adhesives in the form of films or foils
-
- C—CHEMISTRY; METALLURGY
- C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
- C09J—ADHESIVES; NON-MECHANICAL ASPECTS OF ADHESIVE PROCESSES IN GENERAL; ADHESIVE PROCESSES NOT PROVIDED FOR ELSEWHERE; USE OF MATERIALS AS ADHESIVES
- C09J7/00—Adhesives in the form of films or foils
- C09J7/20—Adhesives in the form of films or foils characterised by their carriers
- C09J7/21—Paper; Textile fabrics
-
- C—CHEMISTRY; METALLURGY
- C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
- C09J—ADHESIVES; NON-MECHANICAL ASPECTS OF ADHESIVE PROCESSES IN GENERAL; ADHESIVE PROCESSES NOT PROVIDED FOR ELSEWHERE; USE OF MATERIALS AS ADHESIVES
- C09J7/00—Adhesives in the form of films or foils
- C09J7/40—Adhesives in the form of films or foils characterised by release liners
-
- C—CHEMISTRY; METALLURGY
- C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
- C09J—ADHESIVES; NON-MECHANICAL ASPECTS OF ADHESIVE PROCESSES IN GENERAL; ADHESIVE PROCESSES NOT PROVIDED FOR ELSEWHERE; USE OF MATERIALS AS ADHESIVES
- C09J2301/00—Additional features of adhesives in the form of films or foils
- C09J2301/10—Additional features of adhesives in the form of films or foils characterized by the structural features of the adhesive tape or sheet
- C09J2301/12—Additional features of adhesives in the form of films or foils characterized by the structural features of the adhesive tape or sheet by the arrangement of layers
- C09J2301/124—Additional features of adhesives in the form of films or foils characterized by the structural features of the adhesive tape or sheet by the arrangement of layers the adhesive layer being present on both sides of the carrier, e.g. double-sided adhesive tape
Landscapes
- Chemical & Material Sciences (AREA)
- Organic Chemistry (AREA)
- Adhesives Or Adhesive Processes (AREA)
- Adhesive Tapes (AREA)
Abstract
The invention provides an adhesive composition capable of forming an adhesive layer which maintains the adhesiveness and cohesive force required by the adhesive property, has high stress relaxation property under high temperature environment and has high adhesiveness to low polarity adherends such as polyolefin. The adhesive composition of the present invention comprises a (meth) acrylic copolymer (A) having an acid value of 7.8 to 45, a rosin-based tackifying resin (B) having a softening point of 100 ℃ or higher, and a crosslinking agent (C), wherein the (meth) acrylic copolymer (A) is a copolymer of monomer components comprising an alkyl (meth) acrylate having an alkyl group number of less than 8, an alkyl (meth) acrylate having an alkyl group number of 8 or more, and an acidic group-containing monomer, the content of the rosin-based tackifying resin (B) is more than 16 parts by mass and less than 30 parts by mass, and the content of the crosslinking agent (C) is 0.01 to 5 parts by mass, based on 100 parts by mass of the (meth) acrylic copolymer (A).
Description
Technical Field
The invention relates to an adhesive composition and an adhesive sheet.
Background
At present, materials for automobiles and the like are gradually changing from metal-based materials to plastic-based materials. Background of the shift is the demand for lightweight automobiles and the increasing strength of plastic materials.
However, plastic materials are generally difficult to adhere to adherends, compared with metal materials. In particular, polyolefins such as polypropylene and polyethylene, which are inexpensive and have general-purpose properties, are known as adherends that are difficult to adhere to.
As an adhesive used for bonding these plastic materials that are difficult to bond, an acrylic adhesive containing a tackifier resin is known (for example, see patent document 1).
Patent document 1 discloses an adhesive comprising an acrylic copolymer, a rosin-based resin, and a curing agent of a monomer mixture comprising 60 to 98.5% by weight of butyl acrylate, 1 to 9.9% by weight of a carboxyl group-containing monomer, and 0.5 to 20% by weight of a monomer having a homopolymer glass transition temperature of 15 ℃ or higher and a solubility of less than 1g in 100ml of water at 25 ℃.
As described in patent document 1, various techniques have been proposed for improving adhesiveness and stress relaxation to various adherends by adding a tackifier resin to a (meth) acrylic copolymer. However, when the tackifier resin is excessively added, there are problems of lowering of the adhesive force and cohesive force, clouding of the coating film due to deterioration of compatibility with the (meth) acrylic copolymer, and lowering of the adhesive properties due to precipitation of the surface of the tackifier resin, and it is difficult to improve the adhesiveness to the olefin and the adhesive properties under a high temperature environment while maintaining the basic adhesive properties of the acrylic adhesive.
Documents of the prior art
Patent document
Patent document 1: japanese patent laid-open No. 2016-011339
Disclosure of Invention
Technical problem to be solved by the invention
The present invention addresses the problem of providing an adhesive composition that can form an adhesive layer that has high adhesiveness to a low-polarity adherend such as polyolefin, while having high stress relaxation properties under high-temperature environments, while maintaining the adhesiveness and cohesive force required for adhesive properties.
Technical scheme for solving technical problem
The present inventors have conducted intensive studies to solve the above-mentioned problems. As a result, they have found that the above problems can be solved by an adhesive composition containing specific amounts of a specific (meth) acrylic copolymer and a specific tackifier resin, and have completed the present invention.
The present invention is, for example, the following [1] to [7 ].
[1] An adhesive composition comprising a (meth) acrylic copolymer (A) having an acid value of 7.8 to 45, a rosin-based tackifying resin (B) having a softening point of 100 ℃ or higher, and a crosslinking agent (C),
the (meth) acrylic copolymer (A) is a copolymer of monomer components containing: 20 to 60 mass% of an alkyl (meth) acrylate having an alkyl group with a carbon number of less than 8, 30 to 70 mass% of an alkyl (meth) acrylate having an alkyl group with a carbon number of 8 or more, 1 to 10 mass% of an acid group-containing monomer based on 100 mass% of the total monomer components,
the content of the rosin-based tackifying resin (B) is more than 16 parts by mass and less than 30 parts by mass, and the content of the crosslinking agent (C) is 0.01 to 5 parts by mass, based on 100 parts by mass of the (meth) acrylic copolymer (A).
[2] The pressure-sensitive adhesive composition according to [1], wherein the (meth) acrylic copolymer (A) has a molecular weight of 5000 or less in a proportion of 1.5% or less.
[3] The adhesive composition according to [1] or [2], wherein the adhesive composition contains 0 to 10 parts by mass of a tackifier resin (D) other than the rosin-based tackifier resin (B) per 100 parts by mass of the (meth) acrylic copolymer (A).
[4] The adhesive composition according to [3], wherein a content of the tackifier resin is more than 16 parts by mass and less than 35 parts by mass with respect to 100 parts by mass of the (meth) acrylic copolymer (A).
[5] The adhesive composition according to [3] or [4], wherein the tackifier resin (D) other than the rosin-based tackifier resin (B) is at least 1 tackifier resin selected from the group consisting of styrene resins, C9-based petroleum resins, hydrogenated petroleum resins, terpene-based resins, phenol-based resins, and rosin-based tackifier resins having a softening point of less than 100 ℃.
[6] The adhesive composition according to any one of [1] to [5], wherein the crosslinking agent (C) is at least 1 selected from the group consisting of an isocyanate crosslinking agent (C-1) and a metal chelate crosslinking agent (C-2).
[7] A pressure-sensitive adhesive sheet having a pressure-sensitive adhesive layer prepared from the pressure-sensitive adhesive composition according to any one of [1] to [6 ].
Effects of the invention
The present invention provides an adhesive composition capable of forming an adhesive layer having high adhesiveness to a low-polarity adherend such as polyolefin and having high stress relaxation properties under high temperature environments while maintaining adhesiveness and cohesive force required for adhesive properties, and an adhesive sheet having an adhesive layer prepared from the adhesive composition.
Detailed Description
The adhesive composition and the adhesive sheet of the present invention will be explained below. In the present specification, acrylic acid and methacrylic acid are collectively referred to as "(meth) acrylic acid", and acrylate and methacrylate are collectively referred to as "(meth) acrylate".
[ adhesive composition ]
The adhesive composition of the present invention contains a (meth) acrylic copolymer (a) described below, a rosin-based tackifying resin (B), and a crosslinking agent (C). The adhesive composition of the present invention may contain a tackifier resin (D) other than the rosin-based tackifier resin (B) and an additive (E) as required.
[ (meth) acrylic copolymer (A) ]
The acid value of the (meth) acrylic copolymer (A) is 7.8 to 45. The acid value of the (meth) acrylic copolymer (A) is preferably 8.5 to 40, more preferably 10 to 35. The acid value is a mg value of potassium hydroxide required for neutralizing 1g of the (meth) acrylic acid-based copolymer, and is calculated by the following formula (I). 56.1 in formula (I) is the molecular weight of potassium hydroxide.
Acid value (mgKOH/g) of the polymer 56.1/X (Y/100) × 1000 561/X × Y (i)
X: molecular weight of carboxyl group-containing monomer
Y: incorporation of carboxyl group-containing monomer
The (meth) acrylic copolymer (a) is a copolymer of monomer components containing: the amount of the alkyl (meth) acrylate (a1) having an alkyl group with less than 8 carbon atoms is 20 to 60% by mass, the amount of the alkyl (meth) acrylate (a2) having an alkyl group with 8 or more carbon atoms is 30 to 70% by mass, and the amount of the acidic group-containing monomer (a3) is 1 to 10% by mass, based on 100% by mass of the total monomer components. Hereinafter, these components are also abbreviated as "monomers (a1) to (a 3)". In addition, the hydroxyl group-containing monomer (a4) is also abbreviated as "monomer (a 4)".
The weight average molecular weight (Mw) of the (meth) acrylic copolymer (a) measured by gel permeation chromatography (GPC method) is preferably 20 to 150 ten thousand, more preferably 25 to 130 ten thousand, and further preferably 35 to 120 ten thousand in terms of polystyrene. When Mw is within the above range, a sufficient cohesive force can be imparted to the pressure-sensitive adhesive sheet obtained from the pressure-sensitive adhesive composition, and therefore, the above range is preferable from the viewpoint of improvement in durability under high-temperature conditions or under high-temperature and high-humidity conditions.
The molecular weight distribution (Mw/Mn) of the (meth) acrylic copolymer (A) measured by GPC is preferably 2 to 13, more preferably 2.5 to 10, and still more preferably 2.8 to 8. When the Mw/Mn is within the above range, it is preferable in view of improvement of durability.
In the (meth) acrylic copolymer (a), the proportion of the (meth) acrylic copolymer (low molecular weight component) having a molecular weight of 5000 or less is preferably 1.5% or less, more preferably 1.0% or less, and particularly preferably 0.6% or less. The lower limit of the proportion of the (meth) acrylic copolymer having a molecular weight of 5000 or less is not particularly limited, and is usually 0.01% or more. The ratio is a ratio of the (meth) acrylic copolymer having a molecular weight of 5000 or less, when the total number of molecules of the (meth) acrylic copolymer (a) is 100%. The ratio can be measured by obtaining an integral molecular weight distribution curve by a GPC method. The proportion of the (meth) acrylic copolymer having a molecular weight of 5000 or less in the (meth) acrylic copolymer (a) is preferably in the above range because a pressure-sensitive adhesive layer having a high cohesive force can be obtained. If the proportion of the (meth) acrylic copolymer having a molecular weight of 5000 or less exceeds 1.5%, a layer derived from the low molecular weight component is likely to be formed at the interface between the pressure-sensitive adhesive layer and the adherend when the pressure-sensitive adhesive sheet is adhered to the adherend, and the adhesiveness and heat resistance are undesirably reduced.
The (meth) acrylic copolymer (A) is a copolymer containing 20 to 60 mass% of the monomer (a1), 30 to 70 mass% of the monomer (a2), and 1 to 10 mass% of the monomer (a3) with respect to 100 mass% of the total monomer components. The (meth) acrylic copolymer (A) is preferably a copolymer further containing a monomer component of 0 to 5% by mass of the monomer (a4), more preferably a copolymer containing a monomer component of 30 to 60% by mass of the monomer (a1), 35 to 65% by mass of the monomer (a2), 2 to 8% by mass of the monomer (a3), and 0.01 to 3% by mass of the monomer (a4), and still more preferably a copolymer containing a monomer component of 35 to 50% by mass of the monomer (a1), 45 to 60% by mass of the monomer (a2), 3 to 6% by mass of the monomer (a3), and 0.1 to 2% by mass of the monomer (a 4). The use of the monomers in the above range is preferable because the balance between the adhesive force and cohesive force is good. It is also considered that the (meth) acrylic copolymer (a) produced using the respective monomers in the above-mentioned ranges is excellent in compatibility with the rosin-based tackifying resin (B), and the rosin-based tackifying resin (B) is dispersed in the entire layer of the pressure-sensitive adhesive layer formed from the pressure-sensitive adhesive composition of the present invention. The pressure-sensitive adhesive layer is excellent in stress relaxation property and peeling resistance under constant load because the rosin-based tackifier resin (B) is dispersed in the entire layer. In addition, the heat resistance is also excellent.
Monomer (a1)
Examples of the alkyl (meth) acrylate (a1) having an alkyl group with a carbon number of less than 8 include methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, isopropyl (meth) acrylate, n-butyl (meth) acrylate, isobutyl (meth) acrylate, tert-butyl (meth) acrylate, pentyl (meth) acrylate, hexyl (meth) acrylate, and n-heptyl (meth) acrylate.
As the monomer (a1), n-butyl (meth) acrylate and isobutyl (meth) acrylate are preferable. The monomer (a1) may be used alone in 1 kind, or may be used in 2 or more kinds.
Monomer (a2)
The alkyl (meth) acrylate (a2) having 8 or more alkyl groups is preferably an alkyl (meth) acrylate having 8 to 18 alkyl groups.
Examples of the alkyl (meth) acrylate having an alkyl group with 8 or more carbon atoms include 2-ethylhexyl (meth) acrylate, n-octyl (meth) acrylate, isooctyl (meth) acrylate, nonyl (meth) acrylate, isononyl (meth) acrylate, decyl (meth) acrylate, isodecyl (meth) acrylate, undecyl (meth) acrylate, dodecyl (meth) acrylate, n-octadecyl (meth) acrylate, and isooctadecyl (meth) acrylate.
As the monomer (a2), 2-ethylhexyl (meth) acrylate, n-octyl (meth) acrylate, and isooctyl (meth) acrylate are preferable. The monomer (a2) may be used alone in 1 kind, or may be used in 2 or more kinds.
In the monomer component, the mass ratio of the monomer (a1) to the monomer (a2) is preferably 1: 0.6-1: 2, more preferably 1: 0.7-1: 1.5. if the monomer (a1) and the monomer (a2) are used in the above-mentioned ranges, the compatibility between the (meth) acrylic copolymer (a) and the rosin-based tackifier resin (B) is excellent, and therefore, the use is preferable.
Monomer (a3)
Examples of the acidic group-containing monomer (a3) include a carboxyl group-containing monomer, a sulfonic acid group-containing monomer, and a phosphoric acid group-containing monomer, and a carboxyl group-containing monomer is preferable.
The carboxyl group-containing monomer is a monomer having a carboxyl group in a molecule. Specific examples of the carboxyl group-containing monomer include acrylic acid, methacrylic acid, β -carboxyethyl (meth) acrylate, 5-carboxypentyl (meth) acrylate, mono (meth) acryloyloxyethyl succinate, ω -carboxypolycaprolactone mono (meth) acrylate, crotonic acid, maleic acid, fumaric acid, itaconic acid, and citraconic acid.
As the carboxyl group-containing monomer, at least 1 monomer selected from acrylic acid, methacrylic acid, β -carboxyethyl (meth) acrylate is preferably used, and at least 1 monomer selected from acrylic acid and methacrylic acid is more preferably used. These monomers are industrially readily available and are therefore preferred.
The sulfonic acid group-containing monomer is a monomer having a sulfonic acid group in the molecule. Specific examples of the sulfonic acid group-containing monomer include styrenesulfonic acid, allylsulfonic acid, sulfopropyl (meth) acrylate, 2- (meth) acrylamide-2-methylpropanesulfonic acid, (meth) acrylamidopropanesulfonic acid, and (meth) acryloyloxynaphthalenesulfonic acid.
The phosphoric acid group-containing monomer is a monomer having a phosphoric acid group in the molecule. Specific examples of the phosphoric acid group-containing monomer include 2-hydroxyethyl acryloyl phosphate. The monomer (a3) may be used alone in 1 kind, or may be used in 2 or more kinds.
Monomer (a4)
Examples of the hydroxyl group-containing monomer (a4) include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, 6-hydroxyhexyl (meth) acrylate, 8-hydroxyoctyl (meth) acrylate, 10-hydroxydecyl (meth) acrylate, 12-hydroxydodecyl (meth) acrylate, 4-hydroxymethylcyclohexyl (4-methyl) methyl acrylate, N-methylol (meth) acrylamide, vinyl alcohol, allyl alcohol, 2-hydroxyethyl vinyl ether, and 4-hydroxybutyl vinyl ether. Among them, 2-hydroxyethyl (meth) acrylate and 4-hydroxybutyl (meth) acrylate are preferably used.
The hydroxyl group-containing monomer (a4) is an arbitrary component, and may be 0 mass% in the monomer component, that is, it may not be used, but in order to obtain a pressure-sensitive adhesive layer having a high cohesive force, it is preferable to use a hydroxyl group-containing monomer. In addition, when the isocyanate crosslinking agent (C-1) is used as the crosslinking agent (C), the hydroxyl group-containing monomer (a4) is preferably used from the viewpoint of the curing time of the adhesive sheet because the reactivity of the hydroxyl group-containing monomer with the isocyanate crosslinking agent (C-1) is excellent.
Other monomers (a5)
As the monomer component for obtaining the (meth) acrylic copolymer (a), a monomer other than the above-mentioned monomers (a1) to (a4), that is, another monomer (a5) may also be used.
Examples of the monomer (a5) include alicyclic hydrocarbon group-or aromatic hydrocarbon group-containing (meth) acrylates, alkoxypolyalkylene glycol mono (meth) acrylates, styrene monomers, amide group-containing monomers, amino group-containing monomers, cyano group-containing monomers, and vinyl acetate.
Examples of the (meth) acrylate containing an alicyclic hydrocarbon group or aromatic hydrocarbon group include cyclohexyl (meth) acrylate, isobornyl (meth) acrylate, adamantyl (meth) acrylate, benzyl (meth) acrylate, phenyl (meth) acrylate and phenoxyethyl (meth) acrylate.
Examples of the alkoxypolyalkylene glycol mono (meth) acrylate include methoxydiethylene glycol mono (meth) acrylate, methoxydipropylene glycol mono (meth) acrylate, ethoxytriethylene glycol mono (meth) acrylate, ethoxydiethylene glycol mono (meth) acrylate and methoxytriethylene glycol mono (meth) acrylate.
Examples of the styrene monomer include alkylstyrenes such as styrene, methylstyrene, dimethylstyrene, trimethylstyrene, propylstyrene, butylstyrene, hexylstyrene, heptylstyrene and octylstyrene, halogenated styrenes such as fluorostyrene, chlorostyrene, bromostyrene and dibromostyrene, and functionalized styrenes such as nitrostyrene, acetylstyrene and methoxystyrene.
Examples of the amide group-containing monomer include N-alkyl (meth) acrylamides such as (meth) acrylamide, N-methyl (meth) acrylamide, N-ethyl (meth) acrylamide, N-propyl (meth) acrylamide and N-hexyl (meth) acrylamide, N, N-dialkyl (meth) acrylamides such as N, N-dimethyl (meth) acrylamide and N, N-diethyl (meth) acrylamide, nitrogen-containing heterocyclic monomers such as N-vinylpyrrolidone, N-vinylcaprolactam and (meth) acryloylmorpholine.
Examples of the amino group-containing monomer include N, N-dialkylaminoalkyl (meth) acrylates such as N, N-dimethylaminoethyl (meth) acrylate and N, N-diethylaminoethyl (meth) acrylate.
Examples of the cyano group-containing monomer include cyano (meth) acrylate and (meth) acrylonitrile. The monomer (a5) may be used alone in 1 kind, or may be used in 2 or more kinds.
The monomer (a5) is an optional component, and the content of the monomer (a5) is preferably 20% by mass or less, more preferably 15% by mass or less, and still more preferably 10% by mass or less, per 100% by mass of the monomer components for forming the (meth) acrylic copolymer (a).
Production Condition for (meth) acrylic copolymer (A)
The (meth) acrylic copolymer (a) can be produced by a conventionally known polymerization method such as a solution polymerization method, a bulk polymerization method, an emulsion polymerization method, or a suspension polymerization method, and among them, the solution polymerization method is preferable.
Specifically, the monomer component and, if necessary, a chain transfer agent, a polymerization solvent, etc. are charged into a reaction vessel, and a polymerization initiator is added under an inert gas atmosphere such as nitrogen, for example, to set the reaction starting temperature to usually 40 to 100 ℃, preferably 50 to 80 ℃, and the reaction system is maintained at a temperature of usually 50 to 90 ℃, preferably 60 to 90 ℃ for 2 to 20 hours. In the polymerization reaction, a polymerization initiator, a chain transfer agent, a monomer component, and a polymerization solvent may be added as appropriate. Examples of the polymerization initiator include azo initiators and peroxide polymerization initiators.
Examples of the azo initiator include 2,2' -azobisisobutyronitrile, 2' -azobis (4-methoxy-2, 4-dimethylvaleronitrile), 2' -azobis (2-cyclopropylpropionitrile), 2' -azobis (2, 4-dimethylvaleronitrile), 2' -azobis (2-methylbutyronitrile), 1 ' -azobis (cyclohexane-1-carbonitrile), 2- (carbamoylazo) isobutyronitrile, 2-phenylazo-4-methoxy-2, 4-dimethylvaleronitrile, 2' -azobis (2-amidinopropane) dihydrochloride, 2' -azobis (N, N ' -dimethyleneisobutyramidine), and 2, azo compounds such as 2' -azobis [ 2-methyl-N- (2-hydroxyethyl) -propionamide ], 2' -azobis (isobutyramide) dihydrate, 4 ' -azobis (4-cyanovaleric acid), 2' -azobis (2-cyanopropanol), and dimethyl-2, 2' -azobis (2-methylpropionate).
Examples of the peroxide polymerization initiator include t-butyl hydroperoxide, cumene hydroperoxide, dicumyl peroxide, benzoyl peroxide, lauroyl peroxide, hexanoyl peroxide, diisopropyl peroxide dicarbonate, di-2-ethylhexyl peroxide dicarbonate, t-butyl peroxypivalate, 2-bis (4, 4-di-t-butylcyclohexyl) propane, 2-bis (4, 4-di-t-amylcyclohexyl) propane, 2-bis (4, 4-di-t-octylcyclohexyl) propane, 2-bis (4, 4-di- α -cumylcyclohexyl) propane, 2-bis (4, 4-di-t-butylcyclohexyl) butane, 2-bis (4-peroxide, 4-di-tert-octylcyclohexyl) butane. The polymerization initiator may be used alone in 1 kind, or may be used in 2 or more kinds.
In the production of the (meth) acrylic copolymer (a), a polymerization initiator is used in an amount generally within the range of 0.001 to 5 parts by mass, preferably 0.005 to 3 parts by mass, relative to 100 parts by mass of the monomer component for forming the (a).
Examples of the chain transfer agent include 2-mercaptoethanol, thioglycerol, 3-mercaptohexane-1-ol, thioglycolic acid, 2-mercaptopropionic acid, 3-mercaptopropionic acid, 4-mercaptobutyric acid, 6-mercaptohexanoic acid, 11-mercaptoundecanoic acid, 3-mercaptopyruvic acid, 2-mercaptobenzoic acid, 3-mercaptobenzoic acid, 4-mercaptobenzoic acid, thiomalic acid, n-dodecylmercaptan, pentaerythritol tetrakis (3-mercaptopropionate), α -methylstyrene dimer, and naphthoquinones.
The chain transfer agent may be used alone in 1 kind, or may be used in 2 or more kinds. When a chain transfer agent is used, it is used in an amount within the range of preferably 0.01 to 5 parts by mass, more preferably 0.02 to 3 parts by mass, and still more preferably 0.03 to 2.5 parts by mass, relative to 100 parts by mass of the monomer component forming the (meth) acrylic copolymer (a).
Examples of the polymerization solvent used for the solution polymerization include aromatic hydrocarbons such as benzene, toluene and xylene; aliphatic hydrocarbons such as n-pentane, n-hexane, n-heptane, and n-octane; alicyclic hydrocarbons such as cyclopentane, cyclohexane, cycloheptane, and cyclooctane; ethers such as diethyl ether, diisopropyl ether, 1, 2-dimethoxyethane, dibutyl ether, tetrahydrofuran, dioxane, anisole, phenetole, and diphenyl ether; halogenated hydrocarbons such as chloroform, carbon tetrachloride, 1, 2-dichloroethane, chlorobenzene, and the like; esters such as ethyl acetate, propyl acetate, butyl acetate, and methyl propionate; ketones such as acetone, methyl ethyl ketone, diethyl ketone, methyl isobutyl ketone, and cyclohexanone; amides such as N, N-dimethylformamide, N-dimethylacetamide and N-methylpyrrolidone; nitriles such as acetonitrile and benzonitrile; sulfoxides such as dimethyl sulfoxide and sulfolane. The polymerization solvent may be used alone in 1 kind, or 2 or more kinds.
[ rosin-based tackifying resin (B) ]
The rosin-based tackifier resin (B) having a softening point of 100 ℃ or higher can be used without particular limitation, and the softening point is preferably 100 to 200 ℃, more preferably 120 to 160 ℃ from the viewpoint of providing stress relaxation property in a high-temperature environment.
Examples of the rosin-based tackifying resin (B) having a softening point of 100 ℃ or higher include ペンセル C (softening point 120 ℃ C.), ペンセル D-125 (softening point 125 ℃ C.), ペンセル D-135 (softening point 135 ℃ C.), ペンセル D-160 (softening point 160 ℃ C.), スーパーエステル A-100 (softening point 100 ℃ C.), スーパーエステル A-115 (softening point 115 ℃ C.), スーパーエステル A-125 (softening point 125 ℃ C.), and the like, all of which are manufactured by Mitsukawa chemical industries, Ltd. (Mitsukawa chemical). Further, ハリタック PCJ (softening point 123 ℃ C.), ハリタック DP-2669 (softening point 135 ℃ C.), ハリタック FK125 (softening point 125 ℃ C.) manufactured by Kalima chemical Co., Ltd. (Japanese: ハリマ chemical Co., Ltd.) and the like can be mentioned.
The pressure-sensitive adhesive composition of the present invention contains a specific amount of the (meth) acrylic copolymer (a) and the rosin-based resin (B) at the same time, and therefore the pressure-sensitive adhesive layer obtained from the pressure-sensitive adhesive composition has excellent adhesion to a polyolefin such as polyethylene or polypropylene, i.e., a low-polarity adherend, and also has excellent resistance to peeling under constant load.
In the adhesive composition of the present invention, the content of the rosin-based tackifying resin (B) is more than 16 parts by mass and less than 30 parts by mass, preferably 18 to 28 parts by mass, and more preferably 20 to 26 parts by mass, relative to 100 parts by mass of the (meth) acrylic copolymer (a).
[ crosslinking agent (C) ]
The crosslinking agent (C) may be used without particular limitation. As the crosslinking agent (C), for example, an isocyanate crosslinking agent (C-1), a metal chelate crosslinking agent (C-2) and an epoxy crosslinking agent (C-3) can be used. As the crosslinking agent (C), can use a single kind, can also use 2 or more.
The crosslinking agent (C) is preferably at least 1 selected from the group consisting of an isocyanate crosslinking agent (C-1) and a metal chelate crosslinking agent (C-2), more preferably an isocyanate crosslinking agent (C-1) or a metal chelate crosslinking agent (C-2), and still more preferably an isocyanate crosslinking agent (C-1). The crosslinking agent (C) is preferably an isocyanate crosslinking agent (C-1) in order to improve the adhesion between the pressure-sensitive adhesive layer and the substrate, and is preferably a metal chelate crosslinking agent (C-2) in view of shortening the curing time.
Isocyanate crosslinking agent (C-1)
As the isocyanate crosslinking agent (C-1), an isocyanate crosslinking agent having an isocyanate group of 2 or more in 1 molecule is generally used. The (meth) acrylic copolymer (A) is crosslinked with an isocyanate crosslinking agent (C-1) to form a crosslinked material (network polymer).
The isocyanate group number of the isocyanate crosslinking agent (C-1) is usually 2 or more, preferably 2 to 8, more preferably 3 to 6. When the number of isocyanate groups is within the above range, it is preferable from the viewpoint of the efficiency of the crosslinking reaction of the (meth) acrylic copolymer (A) with the isocyanate compound (C-1) and from the viewpoint of maintaining the flexibility of the adhesive.
Examples of the diisocyanate crosslinking agent having 2 isocyanate groups in 1 molecule include aliphatic diisocyanates, alicyclic diisocyanates, and aromatic diisocyanates. Examples of the aliphatic diisocyanate include aliphatic diisocyanates having 4 to 30 carbon atoms such as ethylene diisocyanate, tetramethylene diisocyanate, pentamethylene diisocyanate, hexamethylene diisocyanate, 2-methyl-1, 5-pentane diisocyanate, 3-methyl-1, 5-pentane diisocyanate, and 2,2, 4-trimethyl-1, 6-hexamethylene diisocyanate. Examples of the alicyclic diisocyanate include alicyclic diisocyanates having 7 to 30 carbon atoms such as isophorone diisocyanate, cyclopentyl diisocyanate, cyclohexyl diisocyanate, hydrogenated xylylene diisocyanate, hydrogenated tolylene diisocyanate, hydrogenated diphenylmethane diisocyanate, and hydrogenated tetramethylxylylene diisocyanate. Examples of the aromatic diisocyanate include aromatic diisocyanates having 8 to 30 carbon atoms such as phenylene diisocyanate, toluene diisocyanate, xylylene diisocyanate, naphthalene diisocyanate, diphenyl ether diisocyanate, diphenylmethane diisocyanate, and diphenyl propane diisocyanate.
Examples of the isocyanate crosslinking agent having 3 or more isocyanate groups in 1 molecule include aromatic polyisocyanates, aliphatic polyisocyanates, and alicyclic polyisocyanates. Specifically, toluene 2,4, 6-triisocyanate, phenyl 1,3, 5-triisocyanate and triphenylmethane 4, 4' -triisocyanate may be mentioned.
Examples of the isocyanate crosslinking agent (C-1) include polymers (e.g., dimers, trimers, biurets, and isocyanurates) of the above-mentioned isocyanate crosslinking agents having an isocyanate number of 2 or more, derivatives (e.g., addition reaction products of a polyol and 2 or more molecules of a diisocyanate crosslinking agent), and polymers. Examples of the polyhydric alcohol in the derivatives include trihydric or higher alcohols such as trimethylolpropane, glycerol and pentaerythritol; examples of the high molecular weight polyol include polyether polyol, polyester polyol, acrylic polyol, polybutadiene polyol and polyisoprene polyol.
Examples of such an isocyanate crosslinking agent include a trimer of diphenylmethane diisocyanate, polymethylene polyphenyl polyisocyanate, a biuret or isocyanurate of hexamethylene diisocyanate or toluene diisocyanate, a reaction product of trimethylolpropane and toluene diisocyanate or xylylene diisocyanate (e.g., a three-molecule adduct of toluene diisocyanate or xylylene diisocyanate), a reaction product of trimethylolpropane and hexamethylene diisocyanate (e.g., a three-molecule adduct of hexamethylene diisocyanate), polyether polyisocyanate, and polyester polyisocyanate.
Among the isocyanate crosslinking agents (C-1), from the viewpoint of good balance of adhesive properties and high durability, a reaction product of trimethylolpropane and tolylene diisocyanate (L-45 manufactured by Hokko chemical Co., Ltd. (Kikoku chemical) or a reaction product of trimethylolpropane and xylylene diisocyanate (TD-75 manufactured by Hokko chemical Co., Ltd.), hexamethylene diisocyanate or an isocyanurate of tolylene diisocyanate (TSE-100 manufactured by Asahi Kasei chemical Co., Ltd. (Asahi Kasei chemical Co., Ltd.), コロネート 2050 manufactured by Tosoh Kasei Co., Ltd. (Du ソー) or the like) is preferable. The isocyanate crosslinking agent (C-1) may be used alone in 1 kind or in 2 or more kinds.
Metal chelate crosslinking agent (C-2)
Examples of the metal chelate crosslinking agent (C-2) include compounds obtained by coordinating a polyvalent metal such as aluminum, iron, copper, zinc, tin, titanium, nickel, antimony, magnesium, vanadium, chromium or zirconium, such as alkoxide, acetylacetone or ethyl acetoacetate.
Among them, an aluminum chelate compound (M-5 ADT, manufactured by Kagaku K.K.) is particularly preferable. Specifically, the aluminum isopropoxide, aluminum sec-butoxide, ethyl aluminum diisopropyl acetoacetate, ethyl aluminum triacetylacetate, and aluminum triacetylacetonate may be mentioned. The metal chelate crosslinking agent (C-2) may be used alone in 1 kind, or may be used in 2 or more kinds.
Epoxy crosslinking agent (C-3)
As the epoxy crosslinking agent (C-3), for example, an epoxy compound having an epoxy group number of 2 or more in 1 molecule is generally used. Examples thereof include ethylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, glycerol triglycidyl ether, 1, 3-bis (N, N-diglycidylaminomethyl) cyclohexane, N, N, N ', N' -tetraglycidylmethylenem-xylylenediamine, N, N, N ', N' -tetraglycidylaminophenylmethane, triglycidyl isocyanurate, m-N, N-diglycidylaminophenylglycidyl ether, N, N-diglycidyltoluidine and N, N-diglycidylaniline. The epoxy crosslinking agent (C-3) may be used alone in 1 kind or in 2 or more kinds.
In the adhesive composition of the present invention, the content of the crosslinking agent (C) is 0.01 to 5 parts by mass, preferably 0.03 to 4.5 parts by mass, and more preferably 0.05 to 3 parts by mass, based on 100 parts by mass of the (meth) acrylic copolymer (a).
[ tackifying resin (D) ]
The adhesive composition of the present invention may contain a tackifier resin (D) other than the rosin-based tackifier resin (B) having a softening point of 100 ℃ or higher as an optional component. The tackifier resin (D) may be a resin other than the rosin-based tackifier resin (B), and is not particularly limited.
In the adhesive composition of the present invention, the content of the tackifier resin (D) is preferably 0 to 10 parts by mass, more preferably 0 to 8 parts by mass, further preferably 0 to 6 parts by mass, and particularly preferably 0 to 5 parts by mass, relative to 100 parts by mass of the (meth) acrylic copolymer (a). In addition, the adhesive composition of the present invention preferably contains substantially no tackifier resin (D) from the viewpoint of stress relaxation property at high temperature, cohesive force and adhesiveness. The substantial absence of the tackifier resin (D) means that the content of the tackifier resin (D) is 0 part by mass or more and less than 0.01 part by mass relative to 100 parts by mass of the (meth) acrylic copolymer (a) in the adhesive composition.
The tackifier resin (D) may, for example, be at least 1 tackifier resin selected from the group consisting of styrene resins, C9 petroleum resins, hydrogenated petroleum resins, terpene resins, phenol resins, and rosin tackifier resins having a softening point of less than 100 ℃. The tackifier resin (D) may be used alone in 1 kind, or may be used in 2 or more kinds.
The amount of the tackifier resin contained in the adhesive composition of the present invention, that is, the total amount of the rosin-based tackifier resin (B) and the tackifier resin (D), is preferably in the range below. In the adhesive composition of the present invention, the content of the tackifier resin is preferably more than 16 parts by mass and less than 35 parts by mass, more preferably 18 to 33 parts by mass, and particularly preferably 20 to 30 parts by mass, relative to 100 parts by mass of the (meth) acrylic copolymer (a). Within the above range, the copolymer is preferably compatible with the (meth) acrylic copolymer (A), exhibits high adhesion to a low-polarity adherend such as olefin and brings about high stress relaxation.
[ additive (E) ]
The adhesive composition of the present invention may contain 1 or 2 or more additives selected from silane coupling agents, antistatic agents, antioxidants, light stabilizers, metal corrosion inhibitors, plasticizers, crosslinking accelerators, surfactants, (meth) acrylic polymers other than the above (a), and rework release agents (リワーク star) in addition to the above components within a range not to impair the effects of the present invention.
When the adhesive composition of the present invention contains the additive (E), the content thereof may be determined as appropriate depending on the kind of the additive, and is usually 0.1 to 30 parts by mass, preferably 0.5 to 20 parts by mass, based on 100 parts by mass of the (meth) acrylic copolymer (a).
[ organic solvent (F) ]
The pressure-sensitive adhesive composition of the present invention preferably contains an organic solvent (F) for adjusting the coatability thereof. Examples of the organic solvent (F) may include the polymerization solvents described in the section "production conditions of the (meth) acrylic copolymer (a)". In the adhesive composition of the present invention, the content of the organic solvent is usually 20 to 90% by mass, preferably 30 to 90% by mass.
In the present specification, "solid content" refers to all components contained in the binder composition except the organic solvent (F), and "solid content concentration" refers to a ratio of the solid content to 100 mass% of the binder composition.
The amount of the (meth) acrylic copolymer (a) in the pressure-sensitive adhesive composition of the present invention is usually 60 mass% or more, preferably 65 mass% or more, and more preferably 70 mass% or more, based on 100 mass% of the solid content. The upper limit of the total amount can be appropriately determined depending on the amounts of other components such as the rosin-based tackifier resin (B) and the crosslinking agent (C).
[ preparation of adhesive composition ]
The adhesive composition of the present invention can be prepared by mixing, for example, the (meth) acrylic copolymer (a), the rosin-based tackifier resin (B), the crosslinking agent (C), and other components as needed by a conventionally known method. For example, the adhesive composition can be prepared by mixing a solution containing the (meth) acrylic copolymer (a) obtained in the synthesis of the (meth) acrylic copolymer (a), the rosin-based tackifying resin (B), the crosslinking agent (C), and other components as necessary.
[ adhesive layer ]
The adhesive layer is prepared from the adhesive composition described above. The pressure-sensitive adhesive layer is obtained, for example, by performing a crosslinking reaction in the above-mentioned pressure-sensitive adhesive composition, specifically, by crosslinking the (meth) acrylate-based copolymer (a) with the crosslinking agent (C).
The conditions for forming the adhesive layer are, for example, as follows. The pressure-sensitive adhesive composition of the present invention is applied to the release-treated surface of a substrate or a release sheet, and the solvent is removed by drying at 50 to 150 ℃ and preferably 60 to 100 ℃ for 1 to 10 minutes and preferably 2 to 7 minutes depending on the kind of the solvent to form a coating film. The thickness of the dried coating film is usually 5 to 100 μm, preferably 10 to 70 μm.
The adhesive layer is preferably formed under the following conditions. The pressure-sensitive adhesive composition of the present invention is applied to the release-treated surface of a substrate or a release sheet, and after the release sheet is adhered to the coating film formed under the above-mentioned conditions, the coating film is cured (cured) in an atmosphere of usually 5 to 60 ℃, preferably 15 to 40 ℃, and usually 30 to 70% RH, preferably 40 to 70% RH for usually 3 days or more, preferably 7 to 10 days. When crosslinking is carried out under the above-mentioned curing conditions, a crosslinked material (network polymer) can be efficiently formed.
As a coating method of the adhesive composition, a known method can be used, and a coating and drying method having a predetermined thickness can be formed by, for example, spin coating, knife coating, roll coating, bar coating, blade coating, die coating, or gravure coating.
The pressure-sensitive adhesive layer formed from the pressure-sensitive adhesive composition of the present invention has good adhesion to polyolefin adherends such as polypropylene and polyethylene, and also has high heat resistance.
[ adhesive sheet ]
The adhesive sheet of the present invention has an adhesive layer prepared from the adhesive composition.
Examples of the pressure-sensitive adhesive sheet include a double-sided pressure-sensitive adhesive sheet having only the pressure-sensitive adhesive layer, a double-sided pressure-sensitive adhesive sheet having a substrate and the pressure-sensitive adhesive layers formed on both sides of the substrate, a single-sided pressure-sensitive adhesive sheet having a substrate and the pressure-sensitive adhesive layer formed on one side of the substrate, and a pressure-sensitive adhesive sheet in which a release sheet is attached to the surface of the pressure-sensitive adhesive layer not in contact with the substrate.
Examples of the substrate and the release sheet include plastic films such as Polycarbonate (PC), polymethyl methacrylate (PMMA), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polyethylene naphthalate (PEN), Polyethylene (PE), polypropylene (PP), ethylene-propylene copolymer, ethylene-vinyl acetate copolymer, acrylonitrile-butadiene-styrene copolymer (ABS), polyamide (nylon), polyimide, and polyvinyl chloride (PVC). Further, the substrate may be glass, paper, nonwoven fabric, or the like.
The conditions for forming the pressure-sensitive adhesive layer were the same as those described in the column of [ pressure-sensitive adhesive layer ].
The thickness of the pressure-sensitive adhesive layer is usually 5 to 100 μm, preferably 10 to 70 μm, from the viewpoint of maintaining the pressure-sensitive adhesive performance. The film thickness of the substrate and the release sheet is not particularly limited, but is usually 10 to 125 μm, preferably 25 to 75 μm.
The pressure-sensitive adhesive sheet formed from the pressure-sensitive adhesive composition of the present invention has good adhesion to polyolefin adherends such as polypropylene and polyethylene, and also has high heat resistance. Further, the adhesive composition has good adhesion to adherends such as resin other than polyolefin and glass.
The pressure-sensitive adhesive sheet of the present invention is useful as various members such as display members, automobile members, airplane members, ship members, and electric appliance members.
Examples
The present invention will be specifically described below based on examples, but the present invention is not limited to these examples. In the following description of examples and the like, "parts" means "parts by mass" unless otherwise specified.
The measurement method of physical properties is as follows.
[ weight average molecular weight (Mw) and number average molecular weight (Mn) ]ratio of molecular weight of 5000 or less in the (meth) acrylic copolymer ]
For the (meth) acrylic copolymer, a differential molecular weight distribution curve and an integral molecular weight curve were obtained by a Gel Permeation Chromatography (GPC) method under the following conditions. Mw and Mw/Mn are determined from a differential molecular weight distribution curve, and a ratio of the molecular weight of 5000 or less is determined from an integral molecular weight distribution curve. The measurement device: HLC-8320GPC (Tosoh corporation) GPC column: the following 4 columns (all available from Tosoh corporation) (1) TSKgel HxL-H (guard column) (2) TSKgel GMHxL (3) TSKgel GMHxL (4) TSKgel G2500HxL flow rate: 1.0 mL/min column temperature: 40 ℃ sample concentration: 1.5% (w/v) (diluted with tetrahydrofuran). mobile phase solvent: tetrahydrofuran-Standard polystyrene conversion
[ acid value ]
The acid value of the (meth) acrylic copolymer (a) is calculated by the following formula (I).
Acid value (mgKOH/g) of the polymer 56.1/X (Y/100) × 1000 561/X × Y (i)
X: molecular weight of carboxyl group-containing monomer
Y: incorporation of carboxyl group-containing monomer
[ Synthesis example A-1]
To a flask equipped with a stirring device, a nitrogen introduction tube, a thermometer, and a reflux condenser, 40 parts of n-Butyl Acrylate (BA), 55.8 parts of isooctyl acrylate (i-OA), 4 parts of Acrylic Acid (AA), 0.2 part of 2-hydroxyethyl acrylate (2HEA), 0.05 part of n-dodecyl mercaptan, and 60 parts of ethyl acetate were added, and the contents of the flask were heated to 70 ℃ while introducing nitrogen into the flask. Then, 0.05 part of 2,2' -azobisisobutyronitrile (hereinafter also referred to as "AIBN") was added to the flask with stirring. Heating and cooling were carried out for 2 hours and 30 minutes so that the temperature of the contents in the flask could be maintained at 70 ℃. After the temperature was raised to 80 ℃, reflux reaction was carried out for 2 hours to obtain (meth) acrylic copolymer (A-1). After the completion of the reaction, the reaction mixture was diluted with ethyl acetate to prepare a polymer solution containing the (meth) acrylic copolymer (A-1) and having a solid content concentration of 45% by mass. Mw measured by GPC on (A-1) was 37 ten thousand, Mw/Mn was 4.5, and the proportion of molecular weight of 5000 or less was 0.1%.
[ Synthesis example A-2]
To a flask equipped with a stirring device, a nitrogen introduction tube, a thermometer, and a reflux condenser, 40 parts of n-Butyl Acrylate (BA), 55.8 parts of 2-ethylhexyl acrylate (2EHA), 4 parts of Acrylic Acid (AA), 0.2 part of 2-hydroxyethyl acrylate (2HEA), and 100 parts of ethyl acetate were added, and the contents of the flask were heated to 70 ℃. Then, 0.05 part of AIBN was added to the flask with stirring. Heating and cooling were carried out for 5 hours and 30 minutes so that the temperature of the contents in the flask could be maintained at 70 ℃ to obtain (meth) acrylic copolymer (A-2). After the completion of the reaction, the reaction mixture was diluted with ethyl acetate to prepare a polymer solution containing the (meth) acrylic copolymer (A-2) and having a solid content concentration of 30% by mass. Mw measured by GPC on (A-2) was 100 ten thousand, Mw/Mn was 7.2, and the proportion of molecular weight of 5000 or less was 0.09%.
Synthesis examples A-3 to A-13
(meth) acrylic copolymers (A-3) to (A-13) were produced in the same manner as in Synthesis example A-1, except that the starting materials shown in Table 1 were used.
[ Table 1]
BA: n-butyl acrylate t-BA: tert-butyl acrylate 2 EHA: 2-ethylhexyl acrylate i-OA: isooctyl acrylate MA: methyl acrylate AA: acrylic acid HEA: 2-hydroxyethyl acrylate HBA: acrylic acid 4-hydroxybutyl ester
[ example 1]
(1) Preparation of adhesive composition
An adhesive composition was obtained by mixing ペンセル D-135 (a rosin-based tackifying resin, softening point 135 ℃ C.) as a tackifying resin (manufactured by Mitsukawa chemical industries, Ltd. (Mitsukawa chemical corporation,)) and L-45 (an isocyanate crosslinking agent, manufactured by Mitsui chemical corporation, solid content concentration 45 mass%) as a crosslinking agent in the solid content ratios of A-1100 parts, D-13525 parts and L-452 parts, respectively (solid content concentration 45 mass%).
(2) Preparation of adhesive sheet
After defoaming, the adhesive composition obtained in (1) was applied to polyethylene terephthalate (PET) with a doctor blade, and dried at 90 ℃ for 3 minutes to remove the solvent so that the dried thickness became 25 μm, thereby forming an adhesive layer. The PET film after the peeling treatment was bonded to the surface of the pressure-sensitive adhesive layer opposite to the surface contacting the PET film. Thereafter, the resulting mixture was left to stand at 23 ℃/50% RH for 7 days to cure the mixture, thereby obtaining an adhesive sheet having an adhesive layer with a thickness of 25 μm.
The pressure-sensitive adhesive composition obtained in (1) was applied to a paper separator after the peeling treatment, and dried at 90 ℃ for 3 minutes to remove the solvent so that the thickness after drying was 65 μm. The resulting adhesive coating film was bonded to both surfaces of a nonwoven fabric substrate having a thickness of 38 μm, and the resultant was left to stand at 23 ℃/50% RH for 7 days to cure the adhesive coating film, thereby obtaining a double-sided adhesive sheet composed of a paper spacer/an adhesive layer/a nonwoven fabric substrate/an adhesive layer/a paper spacer.
(Retention force test)
The adhesive sheet was cut into a size of 20mm × 100mm to prepare a test piece. The obtained test piece was peeled off from the treated PET film, and bonded and pressure-bonded 3 times with a 2kg roller so that the bonding area of the exposed adhesive layer on a stainless steel plate (SUS) was 20mm × 20 mm. Thereafter, the test piece was left to stand at 80 ℃ for 20 minutes in a dry environment, a load of 1kg was applied to the test piece in the shear direction under the same environment, and the amount of deviation of the pressure-sensitive adhesive layer 1 hour after the start of the application of the load was measured.
(constant load peeling test)
The adhesive sheet was cut into 80mm × 20mm dimensions to obtain test pieces. The obtained test piece was peeled off from the treated PET film, adhered to an SUS plate or a polypropylene (PP) plate, and subjected to pressure bonding 3 times to and fro with a 2kg roller so that the bonding area of the exposed adhesive layer was 50mm × 20 mm. Thereafter, the test piece was left to stand at 80 ℃ for 20 minutes in a dry environment, a load of 100g (test on SUS plate) or a load of 50g (test on PP plate) was applied to the end portion on one end side in the longitudinal direction of the test piece in the same environment, and the amount of separation from the SUS plate or the PP plate 1 hour after the application of the load was measured and evaluated according to the following criteria. Standard AA for SUS plate test: the peeling amount is BB below 5 mm: the peeling amount is more than 5mm and below 10mm CC: the peeling amount exceeds the standard AA of 10 mm. PP plate test: the peeling amount is BB below 10 mm: the peeling amount is more than 10mm and below 20mm CC: the peeling amount exceeds 20mm DD: fall down
(rigid body rebound test)
Test pieces were prepared by cutting the double-sided adhesive sheet to a size of 40mm × 110 mm. The resulting test piece was peeled off from the release-treated paper spacer, and one side of the exposed pressure-sensitive adhesive layer was adhered to a polycarbonate sheet 70mm × 110mm × 1.5mm thick, and the other side of the pressure-sensitive adhesive layer was adhered to a polycarbonate sheet 70mm × 150mm × 1.5mm thick, and pressure-bonded in an autoclave (50 ℃, 5atm, 20 minutes). After the plate was taken out, the plate was bent to a radius of curvature of 207mm, and the plate was allowed to stand for 72 hours at 80 ℃ under a dry atmosphere, and then the amount of peeling of the polycarbonate plate was observed.
(ball adhesion test)
Measured by the j.dow method. Specifically, the PET film subjected to the peeling treatment was peeled off from the adhesive sheet, and the sheet was placed on an inclined surface with an inclination angle of 30 degrees to expose the adhesive layer. Then, the steel ball was pushed from the upper side of the inclined surface under an atmosphere of 23 ℃/65% RH, and then slid on the adhesion surface (adhesive layer surface). The pushing distance at this time was 10cm, and the sliding distance was 10 cm. The sliding test was performed by changing the diameter of the steel ball, and the maximum diameter of the steel ball sliding and stopping in the adhesion surface was obtained. The diameter of the steel ball used was X/32 inch (where X is an integer in the range of 1 to 32), and the numerical values shown in Table 2 represent the values of X.
Examples 2 to 13 and comparative examples 1 to 6
Adhesive compositions, adhesive sheets, and double-sided adhesive sheets were obtained in the same manner as in example 1, except that the compounding ingredients were changed as described in table 2 or table 3, and a holding force test, a constant load peel test, a rigid body rebound test, and a ball tack test were performed.
In example 13 using a metal chelate compound as a crosslinking agent, the aging time in the production of the adhesive sheet was 1 day.
[ Table 2]
[ Table 3]
D-135 (Daichuan chemical industry Co., Ltd.: rosin-based tackifier resin, softening point 135 ℃) D-160 (Daichuan chemical industry Co., Ltd.: rosin-based tackifier resin, softening point 160 ℃) DP-2669 (Harlima chemical corporation: rosin-based tackifier resin, softening point 135 ℃) FTR-6100 (Miichuan chemical Co., Ltd.: styrene-based tackifier resin, softening point 100 ℃) T-130 ((Anyuan chemical Co., Ltd.: terpene-based tackifier resin, softening point 130 ℃) L-45 (Daichuan chemical industry Co., Ltd.: isocyanate crosslinking agent, solid content concentration 45% by mass) M-5ADT (Daichuan chemical industry Co., Ltd.: aluminum chelate, solid content concentration 5% by mass).
As is clear from table 2, the pressure-sensitive adhesive sheets obtained in examples 1 to 11 maintained the tackiness and cohesive force required for the adhesive properties, were excellent in stress relaxation property under a high temperature environment, and exhibited high adhesiveness to a low-polarity adherend (PP). The pressure-sensitive adhesive sheet obtained in example 12 using the (meth) acrylic copolymer (A-9) having a molecular weight of 5000 or less and a proportion of 1.7% was inferior to those obtained in examples 1 to 11 in the results of the SUS and PP load peeling test, but had no problem in practical use. The pressure-sensitive adhesive sheet obtained in example 13 using a metal chelate as a crosslinking agent had inferior adhesive properties compared with the other examples, but had an advantage that the curing time after application of the pressure-sensitive adhesive composition could be significantly shortened. The pressure-sensitive adhesive sheets of comparative examples 1 and 2, in which the blending amount of the rosin-based tackifier resin having a softening point of 100 ℃ or higher is out of the range of the present invention, and the pressure-sensitive adhesive sheets of comparative examples 3 and 4, in which the acid value is out of the range of the present invention, are inferior in various adhesive properties.
In addition, the (meth) acrylic copolymer (a-10) in which the blending amount of the alkyl (meth) acrylate having an alkyl group carbon number of less than 8 and the alkyl (meth) acrylate having an alkyl group carbon number of 8 or more was out of the range specified in the present invention was poor in compatibility with the rosin-based tackifier resin, and the adhesive layer was cloudy white (comparative example 5). When the (meth) acrylic copolymer (a-13) obtained by copolymerizing monomers having a high Tg is used to impart heat resistance, the tackiness is significantly reduced, and it is difficult to maintain the balance between the adhesive properties (comparative example 6).
Claims (6)
1. An adhesive composition comprising a (meth) acrylic copolymer (A) having an acid value of 7.8 to 45, a rosin-based tackifying resin (B) having a softening point of 100 ℃ or higher, and
an adhesive composition of a crosslinking agent (C) wherein,
the (meth) acrylic copolymer (A) is a copolymer of monomer components containing: relative to 100 mass% of the total monomer components,
20 to 60 mass% of an alkyl (meth) acrylate having an alkyl group with a carbon number of less than 8,
30 to 70 mass% of alkyl (meth) acrylate having 8 or more alkyl carbon atoms,
1-10 mass% of an acidic group-containing monomer;
the (meth) acrylic copolymer (A) having a molecular weight of 5000 or less is contained in an amount of 1.5% or less,
the content of the rosin-based tackifying resin (B) is more than 16 parts by mass and less than 30 parts by mass, and the content of the crosslinking agent (C) is 0.01 to 5 parts by mass, based on 100 parts by mass of the (meth) acrylic copolymer (A).
2. The adhesive composition according to claim 1, wherein the content of the tackifier resin (D) other than the rosin-based tackifier resin (B) is 0 to 10 parts by mass based on 100 parts by mass of the (meth) acrylic copolymer (A).
3. The adhesive composition according to claim 2, wherein the content of the tackifier resin is more than 16 parts by mass and less than 35 parts by mass with respect to 100 parts by mass of the (meth) acrylic copolymer (a).
4. The adhesive composition according to claim 2, wherein the tackifier resin (D) other than the rosin-based tackifier resin (B) is at least 1 tackifier resin selected from the group consisting of styrene-based resins, C9-based petroleum resins, hydrogenated petroleum resins, terpene-based resins, phenol-based resins, and rosin-based tackifier resins having a softening point of less than 100 ℃.
5. The adhesive composition according to any one of claims 1 to 4, wherein the crosslinking agent (C) is at least 1 selected from the group consisting of an isocyanate crosslinking agent (C-1) and a metal chelate crosslinking agent (C-2).
6. An adhesive sheet comprising an adhesive layer prepared from the adhesive composition according to any one of claims 1 to 5.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2017-076870 | 2017-04-07 | ||
| JP2017076870A JP6850182B2 (en) | 2017-04-07 | 2017-04-07 | Adhesive composition and adhesive sheet |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN108690536A CN108690536A (en) | 2018-10-23 |
| CN108690536B true CN108690536B (en) | 2021-03-30 |
Family
ID=63845444
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201810300180.3A Active CN108690536B (en) | 2017-04-07 | 2018-04-04 | Adhesive composition and adhesive sheet |
Country Status (4)
| Country | Link |
|---|---|
| JP (1) | JP6850182B2 (en) |
| KR (1) | KR102275848B1 (en) |
| CN (1) | CN108690536B (en) |
| TW (1) | TWI716677B (en) |
Families Citing this family (11)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP7187026B2 (en) * | 2019-02-08 | 2022-12-12 | 株式会社トンボ鉛筆 | pressure sensitive transfer adhesive tape |
| JPWO2021075188A1 (en) * | 2019-10-15 | 2021-04-22 | ||
| JP7300599B2 (en) * | 2019-10-30 | 2023-06-30 | 綜研化学株式会社 | Adhesive composition and adhesive sheet |
| CN110819273B (en) * | 2019-12-03 | 2021-10-29 | 苏州凡赛特材料科技有限公司 | Thin-coating high-viscosity pressure-sensitive adhesive and pressure-sensitive adhesive tape |
| CN111154429B (en) * | 2019-12-23 | 2022-06-03 | 崴思新材料泰州有限公司 | Polyacrylate pressure-sensitive adhesive |
| CN116368198A (en) * | 2020-10-05 | 2023-06-30 | 综研化学株式会社 | Adhesive composition for pavement or floor and marking sheet |
| JP7422641B2 (en) | 2020-10-20 | 2024-01-26 | 綜研化学株式会社 | Adhesive composition and adhesive sheet |
| JP7114685B2 (en) * | 2020-12-18 | 2022-08-08 | 日東電工株式会社 | Adhesive sheet |
| JP7176153B2 (en) * | 2020-12-18 | 2022-11-21 | 日東電工株式会社 | Adhesive sheet |
| WO2022208815A1 (en) | 2021-03-31 | 2022-10-06 | 株式会社寺岡製作所 | Pressure-sensitive adhesive composition and pressure-sensitive adhesive tape |
| KR102635559B1 (en) * | 2021-12-07 | 2024-02-08 | (주)이녹스첨단소재 | Adhesive composition and adhesive sheet for display comprising same |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103534324A (en) * | 2011-03-30 | 2014-01-22 | 琳得科株式会社 | Emulsion adhesive composition and re-peelable adhesive sheet |
| CN105518094A (en) * | 2013-09-10 | 2016-04-20 | 积水化学工业株式会社 | Adhesive sheet for electronic devices |
| WO2016154456A1 (en) * | 2015-03-26 | 2016-09-29 | Arizona Chemical Company, Llc | Compositions containing rosin ester and ethylene polymers |
Family Cites Families (16)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2636246B2 (en) * | 1987-07-10 | 1997-07-30 | 日東電工株式会社 | Pressure sensitive adhesive composition |
| JP2732411B2 (en) * | 1989-06-19 | 1998-03-30 | ミネソタ マイニング アンド マニュファクチュアリング カンパニー | Acrylic adhesive |
| JPH0826292B2 (en) * | 1990-11-29 | 1996-03-13 | 積水化学工業株式会社 | Adhesive composition |
| JPH06293880A (en) * | 1993-02-10 | 1994-10-21 | Toyo Ink Mfg Co Ltd | Anaerobically curable tacky agent and sheet or tape |
| JP3278984B2 (en) * | 1993-06-02 | 2002-04-30 | 荒川化学工業株式会社 | Acrylic pressure-sensitive adhesive composition |
| JPH07278513A (en) * | 1994-04-13 | 1995-10-24 | Sekisui Chem Co Ltd | Acrylic tacky agent composition |
| JPH0834962A (en) * | 1994-07-22 | 1996-02-06 | Sekisui Chem Co Ltd | Tacky agent composition and tacky processed article |
| JPH08209078A (en) * | 1995-02-08 | 1996-08-13 | Sekisui Chem Co Ltd | Acrylic tacky tape |
| JP4707816B2 (en) * | 2000-10-23 | 2011-06-22 | 日本合成化学工業株式会社 | Adhesive composition and adhesive tape for recycled parts |
| US7560268B2 (en) | 2004-03-17 | 2009-07-14 | Panasonic Corporation | Process for manufacturing biochip, probe solution, and biochip |
| JP5347115B2 (en) * | 2007-04-24 | 2013-11-20 | 綜研化学株式会社 | Manufacturing method of adhesive |
| JP5688338B2 (en) * | 2011-07-12 | 2015-03-25 | 綜研化学株式会社 | Adhesive, adhesive sheet and laminate for touch panel |
| JP5860297B2 (en) * | 2012-02-06 | 2016-02-16 | 日東電工株式会社 | Acrylic adhesive tape |
| JP5650166B2 (en) * | 2012-07-19 | 2015-01-07 | 日東電工株式会社 | Adhesive sheet, electronic device member laminate, and optical member laminate |
| JP6101165B2 (en) * | 2013-06-27 | 2017-03-22 | 積水フーラー株式会社 | Adhesive composition |
| JP6344091B2 (en) | 2014-06-27 | 2018-06-20 | 東洋インキＳｃホールディングス株式会社 | Adhesive and adhesive sheet |
-
2017
- 2017-04-07 JP JP2017076870A patent/JP6850182B2/en active Active
-
2018
- 2018-03-26 KR KR1020180034423A patent/KR102275848B1/en active IP Right Grant
- 2018-03-27 TW TW107110498A patent/TWI716677B/en active
- 2018-04-04 CN CN201810300180.3A patent/CN108690536B/en active Active
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103534324A (en) * | 2011-03-30 | 2014-01-22 | 琳得科株式会社 | Emulsion adhesive composition and re-peelable adhesive sheet |
| CN105518094A (en) * | 2013-09-10 | 2016-04-20 | 积水化学工业株式会社 | Adhesive sheet for electronic devices |
| WO2016154456A1 (en) * | 2015-03-26 | 2016-09-29 | Arizona Chemical Company, Llc | Compositions containing rosin ester and ethylene polymers |
Also Published As
| Publication number | Publication date |
|---|---|
| KR20180113917A (en) | 2018-10-17 |
| CN108690536A (en) | 2018-10-23 |
| TWI716677B (en) | 2021-01-21 |
| KR102275848B1 (en) | 2021-07-12 |
| JP2018177902A (en) | 2018-11-15 |
| JP6850182B2 (en) | 2021-03-31 |
| TW201837135A (en) | 2018-10-16 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN108690536B (en) | Adhesive composition and adhesive sheet | |
| CN108138004B (en) | Stress dispersion film, optical member, and electronic member | |
| KR102497933B1 (en) | Pressure-sensitive adhesive composition, pressure-sensitive adhesive, and pressure-sensitive adhesive sheet | |
| JP5671500B2 (en) | Resin composition, pressure-sensitive adhesive, and polymer production method | |
| CN108350331B (en) | Composition for adhesive, adhesive layer, and adhesive sheet | |
| CN107011834B (en) | Adhesive composition, adhesive member, optical member, and electronic member | |
| JP6948136B2 (en) | Adhesive composition and adhesive sheet | |
| CN108350332B (en) | Composition for adhesive, adhesive layer, and surface protection sheet | |
| KR102604947B1 (en) | Antistatic agent for pressure sensitive adhesive | |
| CN117120571A (en) | Adhesive composition and adhesive sheet | |
| CN113999633A (en) | Adhesive composition and adhesive sheet | |
| CN113831867A (en) | Adhesive composition, adhesive member, optical member, and electronic member | |
| JPWO2018025808A1 (en) | (Meth) acrylic triblock copolymer, method for producing the same, pressure-sensitive adhesive composition and pressure-sensitive adhesive sheet | |
| CN116194545A (en) | Adhesive composition and adhesive sheet | |
| CN109476771B (en) | (meth) acrylic copolymer, method for producing same, adhesive composition, and adhesive sheet | |
| JP2019044026A (en) | Pressure-sensitive adhesive composition and pressure-sensitive adhesive sheet | |
| JP6004788B2 (en) | RESIN COMPOSITION AND METHOD FOR PRODUCING POLYMER | |
| CN111742024B (en) | Adhesive tape | |
| TWI840331B (en) | Adhesive composition and adhesive sheet | |
| CN116368198A (en) | Adhesive composition for pavement or floor and marking sheet | |
| JP2021070744A (en) | Adhesive composition and adhesive sheet |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |