JPH108011A - Acrylic adhesive composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide excellent adhesiveness in a wide temperature range from a low temperature to a high temperature, exhibit good adhesiveness regardless of the polarity of an adherend, and be suitable for use in a hot melt type. An adhesive composition is provided. SOLUTION: This is an acrylic adhesive composition comprising a block copolymer (I) having a weight average molecular weight of 10,000 to 4,000,000, wherein the block copolymer (I) has a general formula (AB) ) AA, general formula (BA) bB, general formula (AB) c, general formula (AB) mX, and general formula A
One or more block copolymers selected from the group of block copolymers represented by o-T-Bp.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an acrylic adhesive composition.

[0002]

2. Description of the Related Art Adhesive compositions tend to have higher required performance as their applications expand. As the adhesive composition, a rubber-based adhesive composition is conventionally known. However, it is difficult for rubber-based adhesive compositions to respond to increasingly sophisticated performance requirements. Therefore, an acrylic adhesive composition comprising a (meth) acrylate random copolymer having better cohesive strength, weather resistance, oil resistance, and the like than a rubber adhesive composition has been developed and used for various purposes. Have been.

[0003] Acrylic copolymer itself has a tacky feeling and can be used as an adhesive without adding a tackifying resin, but has good adhesion to low-polarity adherends such as polyethylene and polypropylene. Difficult to demonstrate the nature. Further, in order to improve the adhesion to a highly polar adherend such as a metal plate, it is performed to copolymerize a polar monomer such as a carboxyl group-containing monomer, but when the copolymerization amount of such a polar monomer is increased, On the other hand, the adhesive strength to a low-polarity adherend such as polyethylene or polypropylene is reduced to an unacceptably low level. For this reason, a tackifier resin is added for the purpose of improving the adhesive strength to a low-polarity adherend.

However, in the adhesive obtained by adding a tackifying resin to an acrylic copolymer, although the adhesion to a low-polarity adherend at room temperature is improved, the tack at a low temperature is significantly reduced. .

As a method for solving such a problem, Japanese Patent Application Laid-Open No. 3-281587 discloses an acrylic adhesive composition using a specific hydroxyl-containing resin acid ester as a tackifying resin.

[0006] However, although the adhesiveness at low temperature is improved, the cohesive strength is not always satisfactory.

[0007] In recent years, the problem of environmental pollution caused by adhesives using solvents has been taken up severely, and hot-melt adhesive compositions that do not use solvents have come to the fore in terms of energy and resource savings. ing.

[0008] At present, hot-melt type adhesive compositions mainly include ethylene-vinyl acetate copolymers because of their excellent heat-meltability, fluidity, and compatibility with other resins. Mainstream.

However, the hot-melt type adhesive composition containing an ethylene-vinyl acetate copolymer as a main component has a low tackiness and poor adhesion at low temperatures, and is not suitable for olefin copolymers such as polyethylene and polypropylene. Is insufficient in adhesive strength.

As a hot-melt adhesive composition having improved adhesion to a low-polarity adherend such as an olefin-based copolymer,
JP-A-54-91540 discloses a block copolymer comprising a conjugated diolefin polymer and a monovinyl-substituted aromatic compound polymer, an ethylene-vinyl acetate copolymer, an ethylene-based resin, a phenol-based resin, and an adhesive. A resin made of a resin is disclosed.

Japanese Patent Application Laid-Open No. 54-127441 discloses a composition comprising an ethylene-vinyl acetate copolymer, a liquid rubber having a limited molecular weight, and a tackifying resin.

However, since these compounds have a conjugated double bond in their composition, they are not satisfactory in deterioration resistance to light and heat.

As an acrylic hot-melt adhesive composition, JP-A-59-75975 discloses (meth)
A polymer obtained by graft-polymerizing a polymerizable polymer onto a main chain mainly composed of an acrylate ester is disclosed.

However, it is difficult to impart a good balance between thermal fusibility and cohesion. That is,
When this is used as a hot melt adhesive,
At a high temperature of 60 ° C. or higher, the adhesive flows and protrudes from the application portion. If the cohesive force is increased to control the fluidity, the melt viscosity becomes too high and the application becomes difficult.

[0015]

SUMMARY OF THE INVENTION In view of the above problems, the present invention has excellent adhesiveness over a wide temperature range from low to high, and exhibits good adhesiveness regardless of the polarity of the adherend. It is an object of the present invention to provide an acrylic adhesive composition suitable for use in a hot melt type.

[0016]

The acrylic adhesive composition of the present invention is an acrylic adhesive composition comprising a block copolymer (I) having a weight average molecular weight of 10,000 to 4,000,000, The block copolymer (I) has the general formula (A)
-B) aA, general formula (BA) bB, general formula (A-
B) c, general formula (AB) mX, and general formula Ao-T
1 selected from the group of block copolymers represented by -Bp
It is characterized by being at least one kind of block copolymer.

In the formula, A is a vinyl polymer or vinyl copolymer having a glass transition temperature of 20 ° C. or more, or a vinyl monomer having a glass transition temperature of 20 ° C. or more and having a hydroxyl group. Represents a vinyl copolymer.

B has a glass transition temperature of 0 ° C. or less when A is a vinyl polymer or a vinyl copolymer having a glass transition temperature of 20 ° C. or more, and has a hydroxyl group-containing vinyl monomer and an alkyl It represents a copolymer comprising an alkyl (meth) acrylate having 1 to 12 carbon atoms.

B has a glass transition temperature of not more than 0 ° C. when A has a glass transition temperature of not less than 20 ° C. and is a vinyl copolymer containing a hydroxyl group-containing vinyl monomer; It represents a polymer or copolymer comprising an alkyl (meth) acrylate having 1 to 12 carbon atoms in the alkyl group.

X represents a compound residue capable of binding a plurality of copolymers (AB), and T represents a compound residue capable of binding A and B. m represents an integer of 3 to 30, and a, b, and c are the same or different and represent an integer of 1 to 10. o and p are the same or different and each represents an integer of 1 or more;
+ P = 3 to 30. Hereinafter, this is referred to as “acrylic adhesive composition (I)”. Hereinafter, the present invention will be described in detail.

Acrylic adhesive composition (I) of the present invention
Is blended with a block copolymer (I). The block copolymer (I) has a weight average molecular weight of 10,000 to 4,000,000. If it is less than 10,000, the cohesive strength as an adhesive is not sufficient, and if it exceeds 4,000,000, the viscosity increases and the coatability deteriorates, so that it is limited to the above range. Preferably it is 250,000-2,000,000.

The block copolymer (I) has the general formula (AB) aA, the general formula (BA) bB, the general formula (AB) c, the general formula (AB) ) MX, and general formula A
One or more block copolymers selected from the group of block copolymers represented by o-T-Bp are block copolymers bonded via at least one A or B.

The block copolymer represented by each of the above general formulas is a block represented by A, which is a vinyl polymer, a vinyl copolymer, or a vinyl copolymer containing a hydroxyl group-containing vinyl monomer. It has any of the unions.

The above-mentioned vinyl polymer, vinyl copolymer,
Alternatively, a vinyl copolymer containing any of the hydroxyl group-containing vinyl monomers has a glass transition temperature of 20 ° C. or higher. If the temperature is lower than 20 ° C., excellent cohesive strength and adhesiveness cannot be exhibited, so that it is limited to the above range. Preferably, it has a glass transition temperature of 50 to 200 ° C.

The monomers constituting the vinyl polymer and the vinyl copolymer forming the block represented by the above A are not particularly limited. For example, styrene, methyl methacrylate, ethyl methacrylate, α-methyl styrene, o -Methylstyrene, p-methylstyrene, vinyl acetate, (meth) acrylic acid, itaconic acid, crotonic acid,
Maleic acid, maleic anhydride, fumaric acid, 2-hydroxyethyl (meth) acrylate, (meth) acrylonitrile, N-vinylpyrrolidone, acrylamide, methacrylamide, and the like. Of these, styrene and methyl methacrylate are preferred from the viewpoint of improving cohesion. A vinyl polymer can be obtained by using these alone, and a vinyl copolymer can be obtained by using two or more thereof.

The vinyl copolymer containing the hydroxyl group-containing vinyl monomer which forms the block represented by A is obtained by copolymerizing the hydroxyl group-containing vinyl monomer with another vinyl monomer. .

The hydroxyl group-containing vinyl monomer is not particularly restricted but includes, for example, 2-hydroxyethyl (meth) acrylate, hydroxypropyl acrylate,
Examples include 4-hydroxybutyl acrylate, modified caprolactone (meth) acrylate, modified polyoxyethylene oxide (meth) acrylate, and the like.

The other vinyl monomers are not particularly restricted but include, for example, styrene, methyl methacrylate,
Ethyl methacrylate, α-methylstyrene, o-methylstyrene, p-methylstyrene, acrylonitrile,
Vinyl acetate and the like. Of these, styrene and methyl methacrylate are preferred from the viewpoint of improving cohesion. These can be used alone or in combination of two or more.

The content of the hydroxyl group-containing vinyl monomer in the vinyl copolymer containing the hydroxyl group-containing vinyl monomer is preferably 0.1 to 10% by weight. If the amount is less than 0.1% by weight, the cohesive strength as an adhesive is insufficient, and sufficient heat resistance cannot be exhibited. If the amount exceeds 10% by weight, the degree of crosslinking increases, and sufficient adhesive performance is exhibited. Can not do. More preferably, it is 0.5 to 5% by weight.

The above vinyl polymer, vinyl copolymer,
Alternatively, the vinyl copolymer containing a hydroxyl group-containing vinyl monomer preferably has a weight average molecular weight of 5 to 1,000,000. If it is less than 500, the function as a block is not exhibited, and sufficient heat resistance cannot be exhibited. If it exceeds 1,000,000, problems such as an increase in viscosity occur.

The block copolymer represented by each of the above general formulas is a polymer represented by B as an alkyl (meth) acrylate having an alkyl group having 1 to 12 carbon atoms, wherein the alkyl group has 1 to 12 carbon atoms. 1-12 alkyl (meth)
It has a copolymer composed of an acrylate or a copolymer composed of a hydroxyl group-containing vinyl monomer and an alkyl (meth) acrylate having an alkyl group having 1 to 12 carbon atoms.

A polymer comprising an alkyl (meth) acrylate having an alkyl group having 1 to 12 carbon atoms, a copolymer comprising an alkyl (meth) acrylate having an alkyl group having 1 to 12 carbon atoms, and a hydroxyl group-containing vinyl A copolymer composed of a system monomer and an alkyl (meth) acrylate having an alkyl group having 1 to 12 carbon atoms has a glass transition temperature of 0 ° C. or lower. If the temperature exceeds 0 ° C., the tack force is insufficient, and the low-temperature adhesiveness is reduced. Preferably, it has a glass transition temperature of -20 to -50C.

An alkyl group constituting a polymer comprising an alkyl (meth) acrylate having 1 to 12 carbon atoms in the alkyl group and a copolymer comprising an alkyl (meth) acrylate having 1 to 12 carbon atoms in the alkyl group The alkyl (meth) acrylate having 1 to 12 carbon atoms is not particularly limited. For example, methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, isopropyl (meth) acrylate, n- Butyl (meth) acrylate, s-butyl (meth) acrylate, t-butyl (meth) acrylate, cyclohexyl (meth) acrylate, n-octyl (meth) acrylate, isooctyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, Isononyl (meth) acrylate, Uril (meth) acrylate. By using these alone, a polymer comprising an alkyl (meth) acrylate having 1 to 12 carbon atoms in the alkyl group can be obtained, and by using two or more kinds thereof, an alkyl group having 1 to 12 carbon atoms can be obtained. And a copolymer comprising an alkyl (meth) acrylate having the formula:

In the block represented by B, the hydroxyl group-containing vinyl monomer and the alkyl group have 1 to 1 carbon atoms.
The copolymer comprising 12 alkyl (meth) acrylates is obtained by copolymerizing a hydroxyl group-containing vinyl monomer and an alkyl (meth) acrylate having 1 to 12 carbon atoms in the alkyl group. Examples of the hydroxyl group-containing vinyl monomer include those similar to those exemplified for the vinyl copolymer containing the hydroxyl group-containing vinyl monomer forming the block represented by A.

The content of the hydroxyl group-containing vinyl monomer in the copolymer comprising the hydroxyl group-containing vinyl monomer forming the block represented by B and an alkyl (meth) acrylate having an alkyl group having 1 to 12 carbon atoms. Is preferably 0.1 to 5% by weight. If the amount is less than 0.1% by weight, the cohesive strength of the adhesive will be insufficient, and sufficient heat resistance cannot be exhibited. If the amount exceeds 5% by weight, the degree of crosslinking will be high, and sufficient adhesiveness will not be exhibited. More preferably 0.1 to 1
% By weight.

A polymer comprising an alkyl (meth) acrylate having 1 to 12 carbon atoms in the alkyl group, a copolymer comprising an alkyl (meth) acrylate having 1 to 12 carbon atoms in the alkyl group, or a hydroxyl group In a copolymer comprising a vinyl monomer and an alkyl (meth) acrylate having an alkyl group having 1 to 12 carbon atoms, another vinyl may be further added, if necessary, to adjust the glass transition temperature and the adhesive strength. A system monomer can be copolymerized. The other vinyl monomers are not particularly limited, and include, for example, styrene, vinyl acetate, (meth) acrylonitrile, N-vinylpyrrolidone, acryloylmorpholine, and the like.

In a copolymer comprising a hydroxyl group-containing vinyl monomer and an alkyl (meth) acrylate having an alkyl group having 1 to 12 carbon atoms, when the other vinyl monomer is copolymerized, its content is as follows: 55.0
% By weight or less is preferred. If it exceeds 55% by weight, the composition obtained is too hard, and good adhesiveness cannot be exhibited.

A polymer comprising an alkyl (meth) acrylate having 1 to 12 carbon atoms in an alkyl group, a copolymer comprising an alkyl (meth) acrylate having 1 to 12 carbon atoms in an alkyl group, or a vinyl group containing a hydroxyl group A copolymer comprising a monomer and an alkyl (meth) acrylate having an alkyl group having 1 to 12 carbon atoms has a weight average molecular weight of 9500.
Those which are ３００3,000,000 are preferred. If it is less than 9500, the cohesive strength is not sufficient, and if it exceeds 3,000,000, problems such as an increase in viscosity occur.

In the present invention, when the block represented by B is a vinyl polymer or a vinyl copolymer having a glass transition temperature of 20 ° C. or more, the block represented by A is 0. It is a copolymer having a glass transition temperature of not more than ℃ and comprising a hydroxyl group-containing vinyl monomer and an alkyl (meth) acrylate having an alkyl group having 1 to 12 carbon atoms.

The block represented by B is the same as that of A
When the block represented by has a glass transition temperature of 20 ° C. or higher and is a vinyl copolymer containing a hydroxyl group-containing vinyl monomer, it has a glass transition temperature of 0 ° C. or lower and has a carbon group of an alkyl group. Alkyl (meta) having a number of 1 to 12
It is a polymer or copolymer composed of acrylate.

In any of the block copolymers represented by the above general formulas, when a vinyl copolymer containing a hydroxyl group-containing vinyl monomer is used as the block represented by the above A, the content of the vinyl copolymer is not limited. The quantity is 0.5-60.0
Molar% is preferred. If it is less than 0.5 mol%, the heat resistance is not sufficient, and if it exceeds 60.0 mol%, the low-temperature adhesive strength and the initial adhesive strength become insufficient.

The block copolymer represented by the general formula (AB) aA, the block copolymer represented by the general formula (BA) bB, and the block copolymer represented by the general formula (A) -B) In the block copolymer represented by c, a, b and c are the same or different and are integers of 1 to 10. If it exceeds 10, the viscosity increases and the coatability to the base material deteriorates, so that it is limited to the above range. Preferably it is 1-8.

Formula (AB) mX, Formula Ao-T
In the block copolymer represented by -Bp, m represents an integer of 3 to 30. o and p are the same or different and each represent an integer of 1 or more, and o + p = 3 to 30.

In the formula (AB) mX, as the compound residue X capable of binding a plurality of copolymers (AB), for example, the copolymer (AB) When obtained by living polymerization such as anionic polymerization, a polyfunctional initiator containing three or more halogen-containing groups in one molecule such as tetrachlorosilane or trichloromethylbenzene, tetrachloromethylbenzene, pentachloromethylbenzene, hexachloromethylbenzene, etc. Is mentioned. By adding the compound residue X as a polymerization terminator for the copolymer (AB), an (AB) mx block copolymer can be obtained.

In the general formula Ao-T-Bp, examples of the compound residue T capable of binding A and B include an initiator [2, 3 or more containing a peroxide group in one molecule] 2-Bis (4,4-di-t-butylylp
erocyclohexyl) propane (trade name "Pertetra A", manufactured by NOF Corporation) or O
-AllylOO-t-butylmonoperox
ycarbonate (manufactured by NOF Corporation, trade name "Peromer AC") or O-vinylOO-t-but
A copolymer in which a vinyl group-containing peroxide such as ylmonoperoxycarbonate is copolymerized with a monomer constituting the block A or the block B may be used.

In the present invention, the structure of the block copolymer represented by each of the above general formulas is not particularly limited, and examples thereof include those having a linear structure, those having a comb structure, those having a star structure and the like. Is mentioned. Preferably, it has a linear structure. However, it is not preferable to use a macromonomer to obtain a comb structure. This is derived from the process of producing the macromonomer, and the following three problems are raised. (1) Since a dimer as a side reaction product is present in the macromonomer itself, there is a problem that a gel is generated in the polymerization step. If the amount of the macromonomer is reduced to suppress gelation, Inevitably, the desired performance cannot be obtained. (2) If the molecular weight of the macromonomer is increased to tens of thousands or more in order to obtain a comb-shaped copolymer having high molecular weight branches, introduction of a terminal reactive group necessary for addition polymerization becomes difficult, and a large amount of Desired physical properties cannot be obtained due to the unreacted oligomers formed. (3) Since macromonomers are generally synthesized by anionic polymerization, the types of monomers that can be used are limited. In particular, since only a small amount of a polar group can be introduced, the degree of freedom in design is reduced.

When these block copolymers have a star structure, for example, the vinyl copolymer containing the hydroxyl group-containing vinyl monomer is inside and the alkyl group has 1 to 12 carbon atoms. The structure may be such that a polymer comprising an alkyl (meth) acrylate or a copolymer comprising an alkyl (meth) acrylate having 1 to 12 carbon atoms in the alkyl group is provided on the outside.
Alkyl (meth) having 1 to 12 carbon atoms in the alkyl group
A polymer composed of an acrylate or a copolymer composed of an alkyl (meth) acrylate having 1 to 12 carbon atoms in the alkyl group is inside, and a vinyl copolymer containing the hydroxyl group-containing vinyl monomer is outside. It may be a structure.

The method for synthesizing the block copolymer represented by each of the above general formulas is not particularly limited, and examples thereof include a living polymerization method, a method using an initiator having a starting point having a different reactivity, and a method of reacting in one molecule. A method using an initiator having a functional group and a starting point, an ultraviolet polymerization method, and the like can be employed.

According to the above living polymerization method, for example, a hydroxyl group-containing vinyl monomer and another vinyl monomer or an alkyl group having 1 to 12 carbon atoms is used by using a living polymerizable initiator. The polymerization of any one of the (meth) acrylates is performed, and when the polymerization of the block represented by A or the block represented by B is completed, a monomer constituting another polymer or copolymer is added,
A polymerization reaction is further carried out on the terminal of the growing chain, so that the block represented by B or the block represented by A can be polymerized.

The living polymerization method is not particularly restricted but includes, for example, N, N, N ', N'-tetraethyllithium disulfide, benzyl-N, N-diethyldithiocarbamate, p-xylenebis (N, N-diethyl A method using an iniferter such as dithiocarbamate) as an initiator; a method using an organic lanthanoid compound as an initiator; an anionic polymerization method using an alkyllithium or the like as an initiator; a group transfer method using a silylketene acetal or the like as an initiator; aluminum porphyrin Known methods such as metal free living anion method and living radical method can be employed.

The method using an initiator having a starting point having a different reactivity is not particularly limited. For example, a method using an initiator having at least two peroxide groups having different radical generation temperatures, a method using a radical having a different radical generation mechanism, A method using an initiator having at least two oxide groups can be employed.

According to the method using an initiator having at least two peroxide groups having different radical generation temperatures, for example, a hydroxyl group-containing vinyl monomer and other vinyl monomers or an alkyl group Initiates a polymerization reaction of an alkyl (meth) acrylate having 1 to 12 carbon atoms, and a block represented by A or B
After the polymerization of the block represented by is started, the polymerization of the monomer constituting another polymer or copolymer is started from the starting point on the high temperature side, whereby the block B or the block A is started.
Can be carried out.

According to the above-mentioned method using an initiator having at least two peroxide groups having different radical generation mechanisms, for example, a radical is generated by using a reducing agent at one starting point, and a hydroxyl group-containing vinyl monomer and Other vinyl monomers, or alkyl group having 1 to 1 carbon atoms
After the polymerization reaction of the alkyl (meth) acrylate of No. 12 is started and the polymerization of the block represented by A or the block represented by B is started, the temperature is increased and another polymer or copolymer is started from the other starting point. The block B or the block B can be polymerized by starting the polymerization of the monomer constituting the polymer.

More specifically, for example, a hydroxyl group-containing vinyl monomer, another vinyl monomer, and a radical polymerization initiator having two or more peroxide groups in one molecule are mixed at a set temperature level of 1. The reaction is heated to polymerize a vinyl copolymer containing a hydroxyl group-containing vinyl monomer, and then an alkyl (meth) acrylate having an alkyl group having 1 to 12 carbon atoms is added. The block copolymer represented by the general formula (AB) c can be synthesized by performing the heating reaction at the temperature level 2.

The method for using an initiator having a reactive group and a starting point in one molecule is not particularly limited.
A method using an initiator (D) having at least one peroxide group and at least one vinyl group in the molecule can be employed. To use the initiator (D) having at least one peroxide group and at least one vinyl group in one molecule, a photoinitiator different from the initiator (D) or an initiator having a low-temperature activity is used. Alternatively, an alkyl (meth) acrylate having 1 to 12 carbon atoms in an alkyl group is copolymerized with a vinyl group portion of an initiator (D), and A
After the polymerization of the block represented by (B) or the block represented by B, the polymerization of the block B or the block A is carried out by polymerizing the monomer constituting the other block by the peroxide group of the initiator (D). It can be carried out.

According to the ultraviolet polymerization method, for example, first, an alkyl (meth) acrylate having 1 to 12 carbon atoms of the alkyl group and benzyl-N, N-diethyldithiocarbamate are mixed, and the inside of the reaction vessel is mixed with nitrogen. After purging, the polymer is composed of an alkyl (meth) acrylate having 1 to 12 carbon atoms in the alkyl group or an alkyl (meth) having 1 to 12 carbon atoms in the alkyl group by UV irradiation with an ultraviolet (UV) lamp. ) By polymerizing a copolymer comprising acrylate, then adding a hydroxyl group-containing vinyl monomer and other vinyl monomers, and further irradiating UV to polymerize the vinyl copolymer containing the hydroxyl group-containing vinyl monomer. The block copolymer represented by the general formula (AB) aA can be synthesized.

As other methods, for example, a vinyl copolymer containing the above-mentioned hydroxyl group-containing vinyl monomer and having an azo group, or an alkyl group having 1 to 12 carbon atoms (meth) A) a polymer having an azo group or a polymer having an azo group or a copolymer comprising an alkyl (meth) acrylate having 1 to 12 carbon atoms of the alkyl group and having an azo group, A method in which a monomer constituting another polymer or copolymer is polymerized using the group as a starting point can be employed.

Further, a vinyl copolymer containing a hydroxyl group-containing vinyl monomer and a polymer consisting of an alkyl (meth) acrylate having 1 to 12 carbon atoms in an alkyl group, or a Carbon number is 1
After polymerizing a copolymer comprising 12 alkyl (meth) acrylates, by mixing these and irradiating ultraviolet rays, an electron beam, radiation, or the like, a vinyl copolymer containing a hydroxyl group-containing vinyl monomer, A method of block-polymerizing a polymer composed of an alkyl (meth) acrylate having 1 to 12 carbon atoms of an alkyl group or a copolymer composed of an alkyl (meth) acrylate having 1 to 12 carbon atoms of an alkyl group is employed. You can also.

The acrylic adhesive composition (1) of the present invention may contain a random copolymer and a homopolymer composed of monomers constituting the blocks A and B, if necessary.

The acrylic adhesive composition (I) of the present invention may further contain, if necessary, a tackifier resin, a filler, an antioxidant, an ultraviolet absorber, a metal carboxylate, and the like. it can.

The tackifying resin is not particularly restricted but includes, for example, C5 (hydrogenated) petroleum resins and C9 (hydrogenated) petroleum resins.
Petroleum resin, (hydrogenated) rosin resin, (hydrogenated) rosin ester resin, (hydrogenated) terpene resin, (hydrogenated) terpene phenolic resin, (hydrogenated) coumarone indene resin, disproportionated rosin resin, uneven Rosin ester resin, polymerized rosin resin, polymerized rosin ester resin, and the like. These may be used alone or in combination of two or more.

The filler is not particularly restricted but includes, for example, calcium carbonate, titanium oxide, mica, talc and the like.

The antioxidant is not particularly limited.
For example, a phenol type, an amine type and the like can be mentioned.

The ultraviolet absorber is not particularly limited, and examples thereof include benzotriazole-based ones.

The metal carboxylate is not particularly limited, and includes, for example, sodium stearate, magnesium stearate, calcium stearate, zinc stearate, barium stearate, sodium palmitate and the like.

The acrylic adhesive composition according to claim 2, wherein the acrylic adhesive composition (I) further comprises a compound having at least two functional groups capable of reacting with a hydroxyl group. (Hereinafter, this is referred to as “acrylic adhesive composition (II)”).

The compound having at least two functional groups capable of reacting with the above-mentioned hydroxyl group is not particularly restricted but includes, for example, an amino resin obtained by addition condensation of an amino compound such as melamine, benzoguanamine or urea with formaldehyde or alcohol; Tolylene diisocyanate (TD
I) aromatic diisocyanate compounds such as tolidine diisocyanate (TODI), xylylene diisocyanate, diphenylmethane diisocyanate (MDI); aliphatic diisocyanate compounds such as hexamethylene diisocyanate (HMDI) and isophorone diisocyanate (IDI) or alicyclic diisocyanate compounds; Polyisocyanate compounds such as trimethylolpropane tolylene diisocyanate trimer adduct and triisocyanate compounds such as triphenylmethane triisocyanate;
Bifunctional acid anhydrides such as tetracarboxylic anhydride and benzophenonetetracarboxylic anhydride of tetrahydrofuran; alkoxides such as Ti, Zn, and Al; and organic acid metal salts.

The compound having at least two functional groups capable of reacting with the hydroxyl group reacts with the hydroxyl group in the block copolymer (I) to form a crosslinked structure.

The amount of the compound having at least two functional groups capable of reacting with a hydroxyl group is preferably 0.5 to 10% by weight. When the amount is less than 0.5% by weight, the cohesive force of the adhesive is insufficient and sufficient heat resistance cannot be exhibited. When the amount exceeds 10% by weight, the adhesive becomes too hard and exhibits sufficient adhesive performance. Can not. More preferably, it is 1 to 5% by weight.

The acrylic adhesive composition (I) and the acrylic adhesive composition (II) of the present invention are a solvent-based acrylic adhesive composition dissolved in a solvent and an emulsion-type acrylic adhesive dispersed in water. Agent composition and the like.

Further, the acrylic adhesive composition (I) and the acrylic adhesive composition (II) of the present invention can be suitably used as a hot melt adhesive composition.

Further, the acrylic adhesive composition (I) and the acrylic adhesive composition (II) of the present invention can be suitably used as an acrylic pressure-sensitive adhesive composition. And a pressure-sensitive adhesive layer such as a pressure-sensitive adhesive sheet.

The method for producing the pressure-sensitive adhesive tape, the pressure-sensitive adhesive sheet and the like is not particularly limited. For example, a method of coating at least one surface of a base material by a method such as solvent coating or hot-melt coating is employed. can do.

The acrylic adhesive composition (I) and the acrylic adhesive composition (II) of the present invention have both a block A having high rigidity and excellent heat resistance and a block B having a soft and tacky feeling. Therefore, it has good adhesiveness both at low temperatures and at high temperatures.

Further, it has both a low polarity block and a high polarity block containing a hydroxyl group-containing vinyl monomer. Therefore, it has good adhesiveness to a high-polarity adherend such as a metal and a low-polarity adherend such as a plastic regardless of the polarity of the adherend.

[0076]

The present invention will be described in more detail with reference to the following examples, but the present invention is not limited to these examples.

The monomer mixtures (A1) to (A4), (B
Preparation of 1) Each monomer was uniformly mixed according to the formulation shown in Table 1,
A monomer mixture (A1), a monomer mixture (A2), a monomer mixture (A3), a monomer mixture (A4), and a monomer mixture (B1) were prepared.

Example 1 Synthesis of ABA Block Copolymer 80 parts by weight of monomer mixture (B1), 0.2 parts by weight of benzyl-N, N-diethyldithiocarbamate as an initiator, and a solvent Was charged into a three-necked flask and purged with nitrogen for 20 minutes.
While rotating the stirring blade using a three-one motor,
Irradiate a 0 watt ultraviolet (UV) lamp for 48 hours
The block was polymerized. After completion of the reaction, the absence of vinyl groups in the reaction mixture was confirmed by NMR.

The obtained reaction mixture was mixed with 20 parts by weight of the monomer mixture (A1) and ethyl acetate 20 as a solvent.
A 10-watt ultraviolet (UV) lamp was irradiated for 48 hours, and the A block was block-polymerized into the B block to synthesize an ABA block copolymer. After completion of the reaction, the absence of vinyl groups in the reaction mixture was confirmed by NMR. A block Tg is 100 ℃
And the Tg of the B block was −30 ° C.

Preparation of Adhesive Tape An ethyl acetate solution of tolylene diisocyanate adduct of trimethylolpropane as a crosslinking agent was added to 100 parts by weight of the obtained block copolymer (Coronate L5).
5E, solid content 55% by weight, manufactured by Nippon Polyurethane Industry Co., Ltd.)
After adding 2.0 parts by weight and mixing evenly,
m was coated on one surface of a polyester film (# 3811, manufactured by Lintec Corporation) so that the thickness after drying was 50 μm, and dried at 110 ° C. for 5 minutes to obtain an adhesive tape. The adhesive strength of the obtained adhesive tape to a stainless steel plate, the adhesive strength to a polyethylene plate, 80 ° C. holding power, and tack were evaluated by the following methods. The results are shown in Table 2.

Evaluation method Adhesion to stainless steel plate In accordance with JIS Z 0237, SUS304 plate
The obtained adhesive tape was stuck at a width of 25 mm, left at 23 ° C. for 20 minutes, measured at a temperature of 23 ° C. and a tensile speed of 300 mm.
The 180 degree peel strength was measured under the condition of / min.

2. Adhesive force to polyethylene plate The obtained adhesive tape was stuck on a polyethylene resin plate (Hizex 1300J, manufactured by Mitsui Petrochemical Industries, Ltd.) with a width of 25 mm, which was a low-polar adherend, left at 23 ° C. for 20 minutes, and then measured at a measuring temperature. The 180 ° peel strength was measured at 23 ° C. and a tensile speed of 300 mm / min.

3. Measurement of Holding Force at 80 ° C. In accordance with JIS Z 0237, the obtained adhesive tape was stuck on a SUS304 plate with an area of 25 × 25 mm.
After leaving at 23 ° C. for 20 minutes, aging was performed for 1 hour in a constant temperature bath at 80 ° C., a 1 kg suspension load was applied, and the tape displacement or drop time after 1 hour was measured.

4. Tack The ball tack was measured at a measurement temperature of 23 ° C. in accordance with JIS Z 0237.

(Example 2) An ABA block copolymer was synthesized in the same manner as in Example 1 except that the monomer mixture (A2) was used instead of the monomer mixture (A1). The Tg of the A block was 85 ° C, and the Tg of the B block was -30 ° C. A pressure-sensitive adhesive tape was prepared and evaluated in the same manner as in Example 1 except that the obtained block copolymer was used. The results are shown in Table 2.

Comparative Example 1 Monomer Mixture (A1) 20
Radical polymerization was carried out using 1 part by weight, 80 parts by weight of the monomer mixture (B1), and azoisobutyronitrile (AIBN) as an initiator to obtain a random copolymer. An adhesive tape was prepared and evaluated in the same manner as in Example 1 except that the obtained random copolymer was used. The results are shown in Table 2.

(Comparative Example 2) Monomer mixture (A2) 20
Radical polymerization was carried out using 1 part by weight, 80 parts by weight of the monomer mixture (B1), and azoisobutyronitrile (AIBN) as an initiator to obtain a random copolymer. An adhesive tape was prepared and evaluated in the same manner as in Example 1 except that the obtained random copolymer was used. The results are shown in Table 2.

Example 3 Application to Hot Melt Adhesive Ethyl acetate as a solvent was removed from the ABA type block copolymer synthesized in Example 1 using a vacuum dryer. A hot melt adhesive was used. The resulting hot melt adhesive was evaluated for cohesion, melt viscosity at 190 ° C., adhesive strength, and oxidation resistance by the following methods. The results are shown in Table 3.

Evaluation method Cohesive force A test piece was prepared by cutting the obtained hot-melt adhesive into a cube having a side of 5 mm, and the obtained test piece was attached to an aluminum plate held vertically, and the test piece was placed in an oven at 80 ° C.
After leaving for a period of time, the sagging length of the test piece was measured and defined as the cohesive strength.

2.190 ° C. Melt viscosity B-type viscometer (Tokyo Keiki Co., Ltd.) (rotation speed: 2.5 rpm,
The viscosity at 190 ° C. was measured using a rotor: ΔHH4).

3. Adhesive strength Polyethylene plate with clean surface (thickness: 1.5mm, width:
20 mm), a hot-melt adhesive heated to 190 ° C. was applied with a thickness of 1 mm and an area of 10 × 20 mm.
The shear bond strength was measured and defined as the bond strength.

[0092] 4. Oxidation resistance The obtained hot melt type adhesive is 10 mm in thickness of 2 mm.
A test piece cut into a size of × 10 mm was prepared, the obtained test piece was stuck on a glass plate, and the test piece was placed in an oven at 200 ° C. for 8 hours.
After standing for a period of time, a change in the color of the test piece was observed, and the test piece was evaluated as oxidation resistance. The evaluation criteria were "good" if there was no change in color.
The sample having a change in color was defined as “poor”.

Comparative Example 3 By polymerizing isoprene in an n-heptane solvent using an n-butyllithium catalyst, the cis-1,4 bond amount was 80% and the molecular weight was 3
A liquid cis-1,4-polyisoprene rubber having a molecular weight of 6,500 and a cis-1,4-polyisoprene rubber having a molecular weight of 20,6000 were obtained. 35 parts by weight of the obtained liquid cis-1,4-polyisoprene rubber was mixed with Evaflex 210 (vinyl acetate content 28% by weight, melt index (AST)
MD-1238) 400, manufactured by Mitsui Polychemicals) 6
5 parts by weight, 65 parts by weight of YSPX1150 (polyterpene resin, manufactured by Yasuhara Chemical Co., Ltd.), and Nocrack N
S-6 (phenolic antioxidant, manufactured by Ouchi Shinko Chemical Co., Ltd.)
2 parts by weight were mixed and stirred in a mixing tank at 150 ° C. for 30 minutes to obtain an EVA-based adhesive. EVA obtained
The system adhesive was evaluated in the same manner as in Example 3. The results are shown in Table 3.

Comparative Example 4 110 g of cyclohexane pre-dried by a molecular sieve and 400 g of styrene purified by activated alumina were put into a glass and stainless steel reactor, and the temperature of the reactor was raised to 70 ° C. ,
s-butyllithium solution (1.4 in cyclohexane)
M) was added slowly. When a pale reddish orange was obtained, another 100 ml of s-butyllithium solution (0.140 mol in cyclohexane) was immediately added. Next, 1680 g of styrene was added to the reactor over a period of 30 minutes. The temperature was maintained at 70 ° C. for 30 minutes, and 12.3 g of ethylene oxide (0.28 mol) was added to make the solution colorless. Methacryl chloride (0.154) was added to the resulting solution.
(Mol) was obtained to obtain a polymer having a molecular weight of 12,000 as measured by GPC.

200 g of methyl ethyl ketone was put into a resin container equipped with a cooler, a thermometer, a dropping funnel and a stirrer, and heated to reflux. 85.3 g of the obtained polymer (dry weight: 50.0 g), 50.0 g of 2-ethylhexyl acrylate, and 150.g of n-butyl acrylate.
0 g and azoisobutyronitrile 1.
00 g of the mixture was slowly added to the reactor over 30 minutes and refluxed for 2 hours. At the end of the reaction, the polymer solution showed a total solids content of 50.4%. The solvent was removed under vacuum to obtain a transparent adhesive having a molecular weight of 90500. The obtained adhesive was evaluated in the same manner as in Example 3. The results are shown in Table 3.

The monomer mixtures (A5), (A6) and (B
2) Preparation of (B4) According to the composition shown in Table 4, each monomer was uniformly mixed, and the monomer mixture (A5) and the monomer mixture (A
6), monomer mixture (B2), monomer mixture (B
3) and a monomer mixture (B4) were prepared.

Example 4 The same procedure as in Example 1 was carried out except that the monomer mixture (B2) was used instead of the monomer mixture (B1), and the monomer mixture (A5) was used instead of the monomer mixture (A1). An ABA type block copolymer was synthesized. The Tg of the A block was 100 ° C., and the Tg of the B block was −30 ° C. A pressure-sensitive adhesive tape was prepared and evaluated in the same manner as in Example 1 except that the obtained block copolymer was used. The results are shown in Table 2.

Example 5 The same procedure as in Example 1 was carried out except that the monomer mixture (B2) was used instead of the monomer mixture (B1), and the monomer mixture (A6) was used instead of the monomer mixture (A1). An ABA type block copolymer was synthesized. The Tg of the A block was 85 ° C, and the Tg of the B block was -30 ° C. A pressure-sensitive adhesive tape was prepared and evaluated in the same manner as in Example 1 except that the obtained block copolymer was used. The results are shown in Table 2.

(Comparative Example 5) Monomer mixture (A5) 20
Radical polymerization was performed using 100 parts by weight, 80 parts by weight of the monomer mixture (B2), and azoisobutyronitrile (AIBN) as an initiator to obtain a random copolymer. An adhesive tape was prepared and evaluated in the same manner as in Example 1 except that the obtained random copolymer was used. The results are shown in Table 2.

(Comparative Example 6) Monomer mixture (A6) 20
Radical polymerization was performed using 100 parts by weight, 80 parts by weight of the monomer mixture (B2), and azoisobutyronitrile (AIBN) as an initiator to obtain a random copolymer. An adhesive tape was prepared and evaluated in the same manner as in Example 1 except that the obtained random copolymer was used. The results are shown in Table 2.

Example 6 Application to Hot Melt Type Adhesive Ethyl acetate as a solvent was removed from the ABA type block copolymer synthesized in Example 4 using a vacuum dryer. A hot melt adhesive was used. The obtained hot melt adhesive was evaluated in the same manner as in Example 3. The results are shown in Table 3.

Comparative Example 7 By polymerizing isoprene in an n-heptane solvent using an n-butyllithium catalyst, a liquid cis-polymer having a cis-1,4 bond content of 92% and a molecular weight of 39,600 was obtained. 1,4-polyisoprene rubber,
Also, a cis-1,4-polyisoprene rubber having a molecular weight of 245,000 was obtained. An EVA-based adhesive was obtained and evaluated in the same manner as in Comparative Example 5 except that the obtained liquid cis-1,4-polyisoprene rubber was used. The results are shown in Table 3.

Comparative Example 8 An adhesive was prepared in the same manner as in Comparative Example 6, except that the amount of 2-ethylhexyl acrylate was 50.0 g and the amount of n-butyl acrylate was 150.0 g. Obtained and evaluated. Table 3 shows the results
It was shown to.

[0104]

[Table 1]

[0105]

[Table 2]

[0106]

[Table 3]

[0107]

[Table 4]

[0108]

As described above, the acrylic adhesive composition of the present invention has good adhesiveness in a wide temperature range from a low temperature to a high temperature. Further, from a highly polar adherend such as a metal to a low polar adherend such as a plastic, it exhibits good adhesiveness regardless of the polarity of the adherend.

Further, since the acrylic adhesive composition of the present invention is an acrylic adhesive composition, it is excellent in weather resistance, solvent resistance and the like. In addition, since it is made of a block copolymer, the melt viscosity and the cohesive force can be highly balanced, and since it has excellent melting properties, it is suitable for use in a hot melt type.

Claims (4)

[Claims] 1. An acrylic adhesive composition comprising a block copolymer (I) having a weight-average molecular weight of 10,000 to 4,000,000, wherein the block copolymer (I) has the general formula (A- B) aA, general formula (BA) bB, general formula (AB) c, general formula (AB) mx, and general formula A
An acrylic adhesive composition comprising at least one block copolymer selected from the group of block copolymers represented by o-T-Bp. In the formula, A is a vinyl polymer or a vinyl copolymer having a glass transition temperature of 20 ° C. or more, or has a glass transition temperature of 20 ° C. or more;
It represents a vinyl copolymer containing a hydroxyl group-containing vinyl monomer. B has a glass transition temperature of 0 ° C. or less when A is a vinyl polymer or a vinyl copolymer having a glass transition temperature of 20 ° C. or more, and has a hydroxyl group-containing vinyl monomer and an alkyl group The number represents a copolymer of 1 to 12 alkyl (meth) acrylates.
B has a glass transition temperature of 20 ° C. or higher, and when the vinyl copolymer containing a hydroxyl group-containing vinyl monomer has a glass transition temperature of 0 ° C. or lower, B has an alkyl group. It represents a polymer or copolymer composed of an alkyl (meth) acrylate having 1 to 12 carbon atoms. X represents a compound residue capable of binding a plurality of copolymers (AB), and T represents a compound residue capable of binding A and B. m represents an integer of 3 to 30, and a, b, and c are the same or different and represent an integer of 1 to 10. o and p are the same or different and each represent an integer of 1 or more, and o + p = 3 to 30. 2. The acrylic adhesive composition according to claim 1, further comprising a compound having at least two functional groups capable of reacting with a hydroxyl group. 3. A vinyl copolymer having a glass transition temperature of 20 ° C. or more and containing a hydroxyl group-containing vinyl monomer, wherein the content of the hydroxyl group-containing vinyl monomer in the vinyl copolymer is 0.1 to 0.1%.
The acrylic adhesive composition according to claim 1, which is 10% by weight. 4. A polymer having a glass transition temperature of 0 ° C. or lower and a hydroxyl group-containing vinyl monomer and an alkyl group having 1 to 1 carbon atom.
The content of the hydroxyl group-containing vinyl monomer in the copolymer comprising 12 alkyl (meth) acrylates is 0.1 to 0.1%.
The acrylic adhesive composition according to claim 1, which is 5% by weight.