JPH108013A - Acrylic adhesive composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an acrylic adhesive composition which comprises a specific block copolymer, shows excellent adhesion regardless of the polarity of a substrate and is suitably useful as a hot-melt type adhesive of high resistance to weather and solvent. SOLUTION: This acrylic adhesive composition comprises block A and block B different in their composition from each other and containing vinyl monomer bearing carboxyl group, has a weight average molecular weight of 10,000-4,000,000, in which one or more kinds of block copolymers represented by formulas I-IV [A is a vinyl (co)polymer prepared from a carboxyl group- bearing vinyl monomer and an alkyl (meth)acrylate the alkyl of which has 1-12 carbon atoms; B is a copolymer prepared from an alkyl (meth)acrylate the alkyl of which has 1-12 carbon atoms; X is a residue of a compound linking (A-B); T is a residue of a compound for connecting A to B; (m) is 3-30, (a), (b) and (c) are each 1-10; (o) and (p) are each an integer of >=1 and o+p is 3-30] are connected through one or more of blocks A or blocks B, where the copolymerization proportion of the carboxyl-containing vinyl monomer in the block B is smaller than that in the block A.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an acrylic adhesive composition.

[0002]

2. Description of the Related Art A pressure-sensitive adhesive composition is used for a pressure-sensitive adhesive layer such as a pressure-sensitive adhesive tape or a pressure-sensitive adhesive sheet. The adhesive composition is used as a pressure-sensitive adhesive or a hot-melt adhesive. Such pressure-sensitive adhesive compositions and adhesive compositions tend to have higher required performance as their applications expand.

[0003] As the adhesive composition, a rubber-based composition is conventionally known. However, rubber-based pressure-sensitive adhesive compositions do not always have sufficient performances such as cohesive strength, weather resistance, and oil resistance, and it is difficult to respond to increasingly sophisticated performance requirements. Therefore, an acrylic pressure-sensitive adhesive composition comprising a (meth) acrylate random copolymer excellent in cohesive strength, weather resistance, oil resistance, etc., compared to a rubber-based pressure-sensitive adhesive composition, has been developed.
It is used for various purposes.

The acrylic random copolymer itself has a tacky feeling and can be used as an adhesive without adding a tackifier resin, but has good adhesion to low-polarity adherends such as polyethylene and polypropylene. Difficult to demonstrate the nature. When a polar monomer such as a carboxyl group-containing monomer is copolymerized, the adhesion to a highly polar adherend such as a metal plate is improved by increasing the copolymerization amount of such a polar monomer. Adhesion to low polarity adherends is virtually unacceptably low. For this reason, a tackifier resin is added for the purpose of improving the adhesive strength to a low-polarity adherend.

However, the pressure-sensitive adhesive obtained by adding a tackifier resin to an acrylic random copolymer has improved adhesion to low-polarity adherends at room temperature, but has a markedly lower tack at low temperatures. I do.

As a method for solving such a problem,
JP-A-3-281587 discloses an acrylic pressure-sensitive adhesive composition using a resin acid ester having a vinyl-based monomer having a specific hydroxyl group as a tackifying resin. However, although the adhesiveness at low temperatures is improved, the cohesive strength is not always satisfactory.

On the other hand, in recent years, the problem of environmental pollution caused by an adhesive using a solvent has been taken up severely.
From the viewpoint of energy saving and resource saving, hot melt type adhesive compositions which do not use a solvent have been highlighted.

[0008] At present, the hot-melt adhesive composition mainly comprises an ethylene-vinyl acetate random copolymer because of its excellent heat melting property, fluidity and compatibility with other resins. Is the mainstream.

However, the hot-melt adhesive composition containing an ethylene-vinyl acetate random copolymer as a main component does not have sufficient tack, has poor tackiness at low temperatures, and has an olefinic copolymer such as polyethylene or polypropylene. Poor adhesion to low polar adherends such as polymers.

[0010] As a hot-melt adhesive composition having improved adhesion to low-polarity adherends such as olefin copolymers,
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 an ethylene-vinyl acetate copolymer, a liquid rubber having a limited molecular weight, and a tackifier resin. However, since these compounds have a conjugated double bond in the composition, they are not satisfactory in deterioration resistance to light and heat.

Acrylic resin-based hot melt adhesive compositions are also known. It is widely used in various applications because it is excellent in tack and has excellent weather resistance and solvent resistance as compared with rubber-based adhesives.

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

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. Further, if the cohesive force is increased in order to control the fluidity, the melt viscosity becomes too high and the application becomes difficult.

As described above, both the low-polarity adherend and the high-polarity adherend exhibit sufficient adhesiveness and are excellent in the balance between the adhesive property and the melting property. An acrylic pressure-sensitive adhesive composition and an acrylic adhesive composition have not been completed yet.

[0016]

SUMMARY OF THE INVENTION In view of the above, the present invention shows good tackiness regardless of the polarity of the adherend,
An object of the present invention is to provide an acrylic pressure-sensitive adhesive composition suitable for use as a hot melt adhesive.

[0017]

The acrylic adhesive composition of the present invention has a different composition and comprises a block A and a block B containing a vinyl monomer having a carboxyl group.
And 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 (A)
-B) aA, general formula (BA) bB, general formula (A-
B) c, general formula (AB) mX, general formula Ao-TB
a block copolymer in which one or more block copolymers selected from the group of each block copolymer (II) represented by p are bonded via at least one A or B, The copolymerization ratio of the vinyl monomer having a carboxyl group in the block B is smaller than the copolymerization ratio of the vinyl monomer having a carboxyl group in the block A.

In the formula, A is a copolymer (III) comprising a vinyl monomer having a carboxyl group and an alkyl (meth) acrylate having an alkyl group having 1 to 12 carbon atoms.
B is a polymer or copolymer (IV) composed of an alkyl (meth) acrylate having an alkyl group having 1 to 12 carbon atoms, or a vinyl monomer having a carboxyl group and an alkyl group having 1 to 12 carbon atoms. 12 represents a copolymer (V) consisting of 12 alkyl (meth) acrylates.

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, and has a relation of o + p = 3 to 30.

Hereinafter, the present invention will be described in detail. The block copolymer (I) used in the present invention has a weight average molecular weight of 10,000 to
4 million. If the weight average molecular weight is less than 10,000, the cohesive strength 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. The preferred weight average molecular weight is 250,000 to 2,000,000.

The block copolymer (I) in the present invention
Is composed of blocks A and B having different compositions,
Block A and block B contain a vinyl monomer having a carboxyl group. The block copolymer (I) has the general formula (AB) aA, the general formula (B)
-A) b-B, general formula (AB) c, general formula (AB)
It is one or more block copolymers selected from the group of block copolymers represented by mX and Ao-T-Bp.

Each of the block copolymers (II) represented by the above-mentioned general formulas is a vinyl monomer having a carboxyl group and an alkyl (meth) acrylate having 1 to 12 carbon atoms in the alkyl group. (III) consisting of

The vinyl monomer having a carboxyl group is not particularly limited, and examples thereof include (meth) acrylic acid, itaconic acid, crotonic acid, maleic acid, maleic anhydride, and fumaric acid.

The alkyl (meth) acrylate having 1 to 12 carbon atoms in the alkyl group 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, lauryl (meth) acrylate, adamantane (meth) acrylate, dimethyladamantane (meth) acrylate, boronyl (meth) acrylate, isobornyl (meth) acryle Doors and the like. These can be used alone or in combination of two or more.

The copolymer (II) constituting the block A
I) is such that the copolymerization ratio of the above-mentioned carboxyl group-containing vinyl monomer and the above-mentioned alkyl group having 1 to 12 carbon atoms of alkyl (meth) acrylate is 0.5 to 60. 0% by weight,
Alkyl (meth) having 1 to 12 carbon atoms in the alkyl group
The acrylate content is preferably 99.5 to 40.0% by weight.

When the amount of the vinyl monomer having a carboxyl group is less than 0.5% by weight and the alkyl group has 1 to 12 carbon atoms.
If the alkyl (meth) acrylate exceeds 99.5% by weight, the effect of high polarity does not appear, sufficient adhesion performance cannot be obtained, and the vinyl-based monomer having a carboxyl group exceeds 60.0% by weight, The alkyl group has 1 to 1 carbon atoms.
12 alkyl (meth) acrylates at 40.0% by weight
If it is less than 3, the polarity of the composition becomes too high, and the adhesion to the low-polarity adherend decreases as in the case of the composition comprising the conventional random copolymer. More preferably, the vinyl monomer having a carboxyl group is 1.0 to 1
The content of the alkyl (meth) acrylate having 0.01% by weight and the alkyl group having 1 to 12 carbon atoms is 99.0 to 90.0% by weight.

The copolymer (II) constituting the block A
In I), in addition to the vinyl monomer having a carboxyl group and the alkyl (meth) acrylate having 1 to 12 carbon atoms in the alkyl group, if necessary, for adjusting the glass transition temperature and the adhesive performance, Further, other vinyl monomers such as styrene, vinyl acetate, (meth) acrylonitrile, N-vinylpyrrolidone, and acryloylmorpholine can be copolymerized.

In this case, the amount of the other vinyl monomer is preferably 59.5% by weight or less. 59.
If the content exceeds 5% by weight, the pressure-sensitive adhesive composition becomes too hard, and particularly the adhesion to a low-polarity adherend is reduced.

When the block copolymer (I) is used as an acrylic adhesive composition, the amount of the other vinyl monomer is preferably 59.5% by weight or less.
If it exceeds 59.5% by weight, the adhesive composition becomes too hard, and particularly the adhesive strength to a low-polarity adherend decreases.

The copolymer (III) preferably has a glass transition temperature of -100 to 20 ° C. When the temperature is lower than -100 ° C, the adhesive properties such as adhesiveness, tackiness and holding power cannot be exhibited in a well-balanced manner. More preferably, the temperature is from -50 to 20C.

The copolymer (III) preferably has a weight average molecular weight of 500 to 300,000. Weight average molecular weight of 5
If it is less than 00, the function as a block does not appear and 3
If it exceeds 10,000, the adhesive performance to a low-polarity adherend is reduced. More preferably, it is 1,000 to 300,000.

Each of the block copolymers (II) represented by the above general formulas is a polymer or copolymer (alkyl (meth) acrylate) having an alkyl group having 1 to 12 carbon atoms as the block B. IV) or a copolymer (V) comprising a vinyl monomer having a carboxyl group and an alkyl (meth) acrylate having an alkyl group having 1 to 12 carbon atoms.

The polymerization ratio of the vinyl monomer having a carboxyl group in the block B is smaller than the polymerization ratio of the vinyl monomer having a carboxyl group in the block A. When the polymerization ratio of the vinyl-based monomer having a carboxyl group in the block B is equal to or higher than the polymerization ratio of the vinyl-based monomer having a carboxyl group in the block A, an adhesive property corresponding to the polarity of the adherend is exhibited. It is not possible to exhibit good tackiness irrespective of the polarity of the adherend, so that it is limited to the above range.

The vinyl monomer having a carboxyl group is not particularly limited.
And the same as those exemplified in the copolymer (III) comprising the above-mentioned carboxyl-containing vinyl monomer having a carboxyl group and an alkyl (meth) acrylate having 1 to 12 carbon atoms in the alkyl group.

The alkyl group of the alkyl group having a vinyl monomer constituting the block B has 1 to 12 carbon atoms, and the alkyl group of the alkyl (meth) acrylate or the copolymer (IV) has 1 carbon atom. No particular limitation is imposed on the alkyl (meth) acrylate of (1) to (12),
For example, the copolymer (III) constituting the block A
And the same as those exemplified in the above.

In the copolymer (IV) having a vinyl monomer constituting the block B, styrene, vinyl acetate and (meth) acrylonitrile may be further added, if necessary, in order to adjust the glass transition temperature and the adhesive performance. , N-vinylpyrrolidone, acryloylmorpholine, and other vinyl monomers can be copolymerized.

Copolymer (IV) Constituting Block B
Preferably has a glass transition temperature of -100 to 20C. If the temperature is lower than -100 ° C, the adhesive properties such as tackiness, tack, and holding power cannot be exhibited in a well-balanced manner.
When the temperature exceeds 20 ° C., the adhesive performance to a low-polarity adherend is deteriorated. A more preferred glass transition temperature is -100 to 0.
° C.

The copolymer (I) constituting the block B
V) preferably has a weight average molecular weight of 95 to 3,000,000. If it is less than 9500, the cohesive force is not sufficient,
If it exceeds 3,000,000, problems such as an increase in viscosity occur. A more preferred weight average molecular weight is 100,000 to 1,000,000.

In the present invention, the above-mentioned general formula (AB)
aA, general formula (BA) bB, general formula (AB)
c, in each of the block copolymer (II) represented by the general formula (AB) mX and the general formula Ao-T-Bp, the block represented by the above A and the B represented by the above B The blocks have different compositions. For example, there is a case where the block A and the block B are both copolymers composed of two or more kinds of monomers and the constituent monomers are different.

In each of the block copolymers represented by the above general formulas, a vinyl monomer having a carboxyl group forming the block A and an alkyl (meth) acrylate having an alkyl group having 1 to 12 carbon atoms are used. Is preferably 0.5 to 60.0 mol%, respectively. 0.5 mol%
When the amount is less than the above, the adhesive performance corresponding to the polarity of the adherend cannot be exhibited, and when it exceeds 60.0 mol%, the adhesive performance on the low-polar adherend becomes insufficient.

The above general formula (AB) aA and the general formula (B)
-A) In the block copolymer represented by bB and the general formula (AB) c, a, b and c are the same or different,
It is an integer of 1 to 10. If it exceeds 10, the viscosity increases,
Since the coatability to the substrate is deteriorated, the content is limited to the above range.
Preferably it is 1-8.

In the present invention, the structure of each block copolymer (II) 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, and those having a star shape. And the like. 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 from tens of thousands to tens of thousands to obtain a comb-shaped copolymer having high molecular weight branches, it becomes difficult to introduce a terminal reactive group necessary for addition polymerization. Undesired physical properties cannot be obtained due to unreacted oligomers produced as by-products. (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 the block copolymer (II) has a star structure, the structure may be such that the block A is inside and the block B is outside.
The structure may be such that the block B is inside and the block A is outside.

The method for synthesizing each of the block copolymers (II) represented by 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, An ultraviolet polymerization method or the like can be employed.

According to the above-mentioned living polymerization method, first, for example, either one of the above-mentioned block A or the above-mentioned block B is polymerized using a living-polymerizable initiator, and then the above-mentioned block A or the above-mentioned block B is polymerized. At the time when the polymerization of the block B is completed, a monomer constituting another block is added, and a polymerization reaction is further continued at the terminal of the growing chain.
Alternatively, the block A can be polymerized.

The living polymerization method is not particularly limited. 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 alkyllithium or the like as an initiator; a group transfer method using 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 of using an initiator having a starting point having a different reactivity is not particularly limited. For example, a method of using an initiator having at least two peroxide groups having different radical generation temperatures, a method of using a different radical generation mechanism, or the like. A method using an initiator having at least two peroxide groups can be employed.

According to the method using an initiator having at least two peroxide groups having different radical generation temperatures, for example, the monomer constituting the block A or the block B is formed from the starting point on the low temperature side. The polymerization of any one of the monomers is started, and the block A
Alternatively, after the polymerization of the block B is started, the polymerization of the monomers constituting the other blocks 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 using a reducing agent at one starting point to constitute the block A. The polymerization of either the monomer or the monomer constituting the block B is started, and the block A or the block B is started.
After starting the polymerization of, the temperature is increased to start the polymerization of monomers constituting other blocks from the other starting point,
The polymerization of the block B or the block A can be performed.

Specifically, for example, first, a monomer constituting the block A and a radical polymerization initiator having two or more peroxide groups in one molecule are heated and reacted at a set temperature level of 1. Then, the block A is polymerized, and then a monomer constituting the block B is added, and the mixture is heated and reacted at a temperature level 2 which is higher than the temperature level 1 to obtain a polymer represented by the general formula (AB).
The block copolymer represented by c can be synthesized.

The method of using an initiator having a reactive group and an initiation point in one molecule is not particularly limited. For example, an initiator (D) having at least one peroxide group and one vinyl group in one molecule may be used. The method used can be adopted. In the method using an initiator (D) having at least one peroxide group and at least one vinyl group in one molecule, the number of carbon atoms of a vinyl monomer or an alkyl group may be changed by using a photoinitiator different from the above or an initiator having low-temperature activity. Are copolymerized with the alkyl (meth) acrylate of 1 to 12 and the vinyl group portion of the initiator (D), and after polymerizing the block A or the block B, the other block is formed by the peroxide group of the initiator (D). By polymerizing the constituent monomers, the block A or the block B can be polymerized.

According to the ultraviolet polymerization method, for example, first, the monomer constituting the block B and benzyl-
After mixing with N, N-diethyldithiocarbamate and purging the inside of the reaction vessel with nitrogen, the block B is polymerized by UV irradiation with an ultraviolet (UV) lamp, and then the monomer constituting the block A is added. By further irradiating UV to polymerize the vinyl copolymer, the block copolymer represented by the general formula (AB) aA can be synthesized.

As another method, the above-mentioned block A having an azo group or the above-mentioned block B having an azo group is polymerized to form another block starting from the azo group. The method of polymerizing the monomer to be performed, the block A, and the block B are polymerized in advance by ordinary radical polymerization or the like, and then the mixture is mixed and irradiated with ultraviolet light, an electron beam, radiation, or the like, so that the block A A method of performing block polymerization of the block B and the like may be employed.

In the above block copolymer (I),
A crosslinking agent can be added to improve cohesion. The crosslinking agent is not particularly limited, and for example, N, N'-
Hexamethylene-1,6-bis (1-aziridinecarbamide), N, N'-diphenylmethane-1,6-bis (1-aziridinecarbamide), trimethylol-tri-β-aziridinylpropionate, etc. A di- or more functional aziridine compound; hexamethylene diisocyanate,
Isocyanate compounds such as tolylene diisocyanate adduct of trimethylolpropane; N, N, N ', N'
Epoxy resins such as tetraglycidyl-m-xylenediamine; alkyl etherified melamine resins; polyvalent metal salts; metal chelates and the like.

The block copolymer (I) may contain up to 90% by weight of a random copolymer (VI) or a homopolymer. Random copolymer (VI)
Alternatively, the homopolymer has an alkyl group having 1 to 12 carbon atoms.
A polymer consisting of acrylic (meth) acrylate or a copolymer of two or more monomers selected from the alkyl (meth) acrylate monomer and vinyl monomer is used, and the block copolymer (I) It is preferable that the composition be close to the composition of

As the compound residue X capable of binding a plurality of copolymers (AB), for example, when the copolymer (AB) is obtained by living polymerization such as anionic polymerization, Examples thereof include polyfunctional initiators containing three or more halogen-containing groups in one molecule, such as chlorosilane or trichloromethylbenzene, tetrachloromethylbenzene, pentachloromethylbenzene, and hexachloromethylbenzene. By adding the compound residue X as a polymerization terminator for the copolymer (AB), an (AB) mx block copolymer can be obtained.

The compound residue T capable of bonding A and B includes, for example, an initiator [2,2-Bis (4,4-d) having at least three peroxide groups in one molecule.
it-butyloxycyclohexy
l) propane (trade name "Pertetra A", manufactured by NOF Corporation) or O-allylOO-t-but
ylmonoperoxycarbonate (trade name "Peromer AC", manufactured by NOF Corporation) or O-vi
nylOO-t-butylmonoperoxyca
Copolymers obtained by copolymerizing a vinyl group-containing peroxide such as rbonate with the constituent monomers of the block A or the block B are exemplified.

In the acrylic pressure-sensitive adhesive composition of the present invention and the acrylic pressure-sensitive adhesive composition of the present invention, if necessary, a tackifying resin, a filler, an antioxidant, an ultraviolet absorber, a metal carboxylate may be used. Salts and the like can be added.

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 can 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 restricted but includes, for example, sodium stearate, magnesium stearate, calcium stearate, zinc stearate, barium stearate, sodium palmitate and the like.

The acrylic pressure-sensitive adhesive composition of the present invention can be suitably used, for example, as a pressure-sensitive adhesive layer of a pressure-sensitive adhesive tape, a pressure-sensitive adhesive sheet or the like.

The method for producing the pressure-sensitive adhesive tape, the pressure-sensitive adhesive sheet, and the like is not particularly limited, and for example, a method of coating at least one surface of a substrate by a method such as solvent coating or hot-melt coating is employed. be able to.

The method of applying the solvent is not particularly limited. For example, a method of dissolving the acrylic pressure-sensitive adhesive composition of the present invention in a solvent, applying the composition to a base film, and drying the solvent may be employed. Can be.

The method by the hot melt coating is not particularly limited. For example, the acrylic pressure-sensitive adhesive composition of the present invention is integrally formed with a base film and, if necessary, a primer resin by a multilayer coextrusion method. And the like. According to the multilayer co-extrusion molding method, the base film, the acrylic pressure-sensitive adhesive composition, and the primer resin are each plasticized by a separate extruder, and an inflation method, using a multilayer extrusion mold such as a T-die method, The base layer / primer layer / adhesive layer can be sequentially laminated by co-extrusion in a hot-melt system.

As one of the methods by the hot melt coating, a method of manufacturing by a hot melt coating method can be adopted. According to the hot melt coating method, if necessary, a primer layer is previously formed on one side of the base film by an appropriate method, and hot melt coating can be performed by a hot melt coater on the primer layer. .

By molding only the acrylic pressure-sensitive adhesive composition of the present invention into a sheet, a non-support type double-sided pressure-sensitive adhesive tape having no base material layer can be obtained.

The acrylic adhesive composition of the present invention can be suitably used, for example, as a solvent-type acrylic adhesive composition dissolved in a solvent, an emulsion-type acrylic adhesive composition dispersed in water, and the like. . Specifically, for example, the acrylic adhesive composition of the present invention is dissolved in a solvent, or, after being dispersed in water, directly applied to the adherends, after the adherends are bonded together, the solvent Alternatively, the adherends can be bonded to each other by drying and removing water.

Further, the acrylic adhesive composition of the present invention can be suitably used as a hot-melt adhesive composition. Specifically, for example, it is possible to bond the adherends by heating and melting them without a solvent, coating the adherends, bonding the adherends, and then cooling.

The acrylic pressure-sensitive adhesive composition of the present invention and the acrylic adhesive composition of the present invention can be suitably used for other applications such as paints and coatings.

The acrylic pressure-sensitive adhesive composition of the present invention and the acrylic adhesive composition of the present invention have both the high-polarity block A and the low-polarity block B. Thus, the surface polarity of the composition can be controlled. Accordingly, good adhesiveness is obtained regardless of the polarity of the adherend, even for highly polar adherends such as glass and metal, and also for low-polarity adherends such as polyethylene and polypropylene. Demonstrate.

[0075]

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 (A3), (B
Preparation of 1) to (B3) According to the composition shown in Table 1, the respective monomers were uniformly mixed, and the monomer mixture (A1) and the monomer mixture (A
2), monomer mixture (A3), monomer mixture (B
1), the monomer mixture (B2) and the monomer mixture (B
3) was prepared.

[0077]

[Table 1]

(Example 1) 95 parts by weight of a monomer mixture (B1) of a block copolymer, 0.2 parts by weight of benzyl-N, N-diethyldithiocarbamate as an initiator, and 30 parts by weight of ethyl acetate as 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, 10
A B-block was polymerized by irradiating a watt ultraviolet (UV) lamp for 48 hours. After completion of the reaction, the absence of vinyl groups in the reaction mixture was confirmed by NMR.

To the obtained reaction mixture, 5 parts by weight of the monomer mixture (A1) and 20 parts by weight of ethyl acetate as a solvent were added, and an ultraviolet (UV) lamp of 10 watts was used.
By irradiating for 8 hours, the A block was block-polymerized into the B block to synthesize an ABA type block copolymer. After completion of the reaction, the absence of vinyl groups in the reaction mixture was confirmed by NMR.

Preparation of Adhesive Tape An ethyl acetate solution of tolylenediisocyanate trimethylolpropane adduct (coronate L5) was used as a crosslinking agent with respect to 100 parts by weight of the obtained block copolymer.
5E, solid content 55% by weight, manufactured by Nippon Polyurethane Industry Co., Ltd.)
After adding 1.0 part by weight and mixing uniformly, a thickness of 38 μ
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, polyethylene adhesive strength 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 pressure-sensitive adhesive tape was stuck at a width of 25 mm, left at 23 ° C. for 20 minutes, and the peel strength was measured at a measuring temperature of 23 ° C., in a direction of 180 °, and at a pulling speed of 300 mm / min.

2. Adhesive force to polyethylene resin plate The obtained adhesive tape was adhered to 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 measured. Temperature 23 ° C, 180 ° direction, pulling speed 300m
The peel strength was measured under the condition of m / min.

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

Example 2 The same procedure as in Example 1 was carried out except that the monomer mixture (A2) was used instead of the monomer mixture (A1), and the monomer mixture (B2) was used instead of the monomer mixture (B1). An adhesive tape was obtained and evaluated. The results are shown in Table 2.

Example 3 The same procedure as in Example 1 was carried out except that the monomer mixture (A3) was used instead of the monomer mixture (A1), and the monomer mixture (B3) was used instead of the monomer mixture (B1). An adhesive tape was obtained and evaluated. The results are shown in Table 2.

Comparative Example 1 Radical polymerization was carried out using 5 parts by weight of the monomer mixture (A1), 95 parts by weight of the monomer mixture (B1), and azoisobutyronitrile (AIBN) as an initiator. A coalescence was obtained. An adhesive tape was obtained 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 Radical polymerization was carried out using 5 parts by weight of the monomer mixture (A2), 95 parts by weight of the monomer mixture (B2), and azoisobutyronitrile (AIBN) as an initiator. A coalescence was obtained. An adhesive tape was obtained 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 3 Radical polymerization was carried out using 5 parts by weight of the monomer mixture (A3), 95 parts by weight of the monomer mixture (B3), and azoisobutyronitrile (AIBN) as an initiator. A coalescence was obtained. A pressure-sensitive adhesive tape was obtained 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.

[0089]

[Table 2]

Example 4 Application to Hot Melt Adhesive 80 parts by weight of butyl acrylate, 0.2 part by weight of benzyl-N, N-diethyldithiocarbamate as an initiator,
Then, 30 parts by weight of ethyl acetate as a solvent was charged into a three-necked flask, and purged with nitrogen for 20 minutes. While rotating the stirring blades using a three-one motor, a 10-watt ultraviolet (UV) lamp was irradiated for 48 hours to polymerize the B block. 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 a monomer mixture composed of 90% by weight of methyl methacrylate and 10% by weight of acrylic acid, and ethyl acetate 2 as a solvent.
0 parts by weight were added, and a 10-watt ultraviolet (UV) lamp was irradiated for 48 hours to block-polymerize the A block into the B block, thereby synthesizing an ABA block copolymer. After completion of the reaction, the absence of vinyl groups in the reaction mixture was confirmed by NMR.

Ethyl acetate as a solvent was removed from the obtained block copolymer to obtain a hot melt adhesive. Cohesive force of the obtained hot melt adhesive, 190 ° C.
The melt viscosity, adhesive strength, and oxidation resistance were evaluated by the following methods. The results are shown in Table 3.

Evaluation method Cohesive force The obtained hot-melt type adhesive is cut into 5 × 5 × 5 mm square to form a test piece, and the obtained test piece is stuck on an aluminum plate held vertically, and is placed in an oven at 80 ° C. for 12 hours. After the standing, the sagging length of the test piece was measured and defined as the cohesive strength.

2. 190 ° C. Melt viscosity B-type viscometer (manufactured by 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 in an area of 1 mm in thickness and 10 × 20 mm, and the shear adhesive strength was measured to determine the adhesive strength.

4. Oxidation resistance The obtained hot-melt type adhesive is cut into 10 × 10 × 2 mm square to form a test piece, and the obtained test piece is stuck on a glass plate and left in an oven at 200 ° C. for 8 hours. A change in the color of the test piece was observed, and the test piece was evaluated as oxidation resistance. Evaluation criteria are
Those with no color change were rated "good", and those with color change were rated "poor".

(Comparative Example 4) 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 80% and a molecular weight of 39000 was obtained. 1,4-polyisoprene rubber,
And cis-1,4-polyisoprene rubber having a molecular weight of 231,000 was 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 (AS)
TM-D-1238) 400, manufactured by Mitsui Polychemicals)
65 parts by weight, YSPX1150 (polyterpene resin,
65 parts by weight of Yasuhara Chemical Co., Ltd. and 2 parts by weight of Nocrack NS-6 (phenolic antioxidant, manufactured by Ouchi Shinko Chemical Co., Ltd.) are mixed, and the mixture is stirred in a mixing tank at 150 ° C. for 30 minutes to bond EVA. Agent was obtained. EV obtained
The A-based adhesive was evaluated in the same manner as in Example 3. The results are shown in Table 3.

Comparative Example 5 110 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 color was obtained, further s-butyllithium solution (0.1
100 ml) were added immediately. 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. 16.1 g of methacroyl chloride (0.154 mol) was added to the obtained solution to obtain a polymer monomer having a molecular weight of 12,000 as measured by GPC.

200 g of methyl ethyl ketone was charged 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 monomer (50.0 g in dry weight), 150.0 g of 2-ethylhexyl acrylate, 50.5 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.

[0100]

[Table 3]

[0101]

The acrylic pressure-sensitive adhesive composition of the present invention has the above-mentioned structure, and is used to cover a wide range of adherends, from high polar adherends such as metals to low polar adherends such as plastics. Shows good tackiness regardless of polarity.

Furthermore, since it is an acrylic 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 as a hot melt adhesive.

Claims (2)

[Claims] 1. Blocks A and B having different compositions and containing a vinyl monomer having a carboxyl group.
And 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 (A-
B) c, general formula (AB) mX, and general formula Ao-T
Each block copolymer (II) represented by -Bp
Is a block copolymer in which at least one block copolymer selected from the group of is bonded via at least one A or B, and a copolymer of a vinyl monomer having a carboxyl group in the block B An acrylic adhesive composition having a polymerization ratio smaller than a copolymerization ratio of a vinyl monomer having a carboxyl group in the block A. Where A
Represents a copolymer (III) comprising a vinyl monomer having a carboxyl group and an alkyl (meth) acrylate having an alkyl group having 1 to 12 carbon atoms, and B represents an alkyl (meta) having an alkyl group having 1 to 12 carbon atoms. A) a polymer or copolymer (IV) comprising an acrylate, or a copolymer (V) comprising a vinyl monomer having a carboxyl group and an alkyl (meth) acrylate having an alkyl group having 1 to 12 carbon atoms. X is 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 are 1 to 1
Represents an integer of 0. o and p are the same or different and each represents an integer of 1 or more, and has a relation of o + p = 3 to 30. 2. A copolymer (III) comprising a carboxyl group-containing vinyl monomer and an alkyl (meth) acrylate having an alkyl group having 1 to 12 carbon atoms is a carboxyl group-containing vinyl monomer 0.5 to 60. .0
The acrylic adhesive composition according to claim 1, which is a copolymer of 99.5 to 40% by weight of an alkyl (meth) acrylate having 1 to 12 carbon atoms in the alkyl group.