JP3168376B2 - Cyanoacrylate adhesive composition - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cyanoacrylate adhesive composition having excellent shear adhesive strength and impact adhesive strength.

[0002]

2. Description of the Related Art Cyanoacrylate adhesives containing an α-cyanoacrylate monomer as an essential component are:
Because it rapidly polymerizes and hardens due to a small amount of moisture adsorbed on the adherend surface, and almost all materials except polyethylene and some inactive materials such as Teflon adhere very strongly in a short time, As a room temperature one-pack type instant adhesive,
Widely used for bonding metals, plastics, rubber, wood, etc. However, cyanoacrylate-based adhesives have been positioned as temporary fixing adhesives because of their poor impact strength. In order to improve such disadvantages, cyanoacrylate adhesive compositions modified with various additives have been proposed.

[0003] US Pat. No. 4,102,945 describes:
Acrylonitrile-butadiene-styrene terpolymer (AB) which is an impact modifier for vinyl chloride resin
An adhesive composition comprising a copolymer selected from S), a methacrylate-butadiene-styrene terpolymer (MBS) and a vinylidene chloride-acrylonitrile copolymer (VAC) is disclosed.

[0004] In US Pat. No. 4,560,723 (corresponding to Japanese Patent Publication No. 5-59949), the core-shell polymer disclosed in the above-mentioned US patent has a disadvantage that the storage stability of a cyanoacrylate adhesive is significantly impaired. In addition to the fact that an adhesive composition comprising a core-shell copolymer as a reinforcing agent that has been treated to remove impurities that cause premature polymerization of a cyanoacrylate adhesive and a sustaining agent that prevents heat aging has been pointed out. It has been disclosed.
However, this adhesive composition has a problem that although the heat aging of the peeling adhesive strength is suppressed by the addition of a sustaining agent for preventing heat aging, the cohesive force is reduced by the sustaining agent acting as a plasticizer. Have a point. This decrease in the cohesive strength of the adhesive results in impairing the shear adhesive strength, impact adhesive strength, moisture resistance, and the like. Further, among the sustaining agents disclosed therein, halogenated benzene compounds in particular have a peculiar unpleasant odor, which is not preferable for the working environment and the human body. In order to further improve the storage stability of the composition, a treatment for removing impurities of the core-shell polymer is an essential condition, but a multi-step treatment step is not industrially preferable.

[0005]

SUMMARY OF THE INVENTION An object of the present invention is to provide a cyanoacrylate adhesive composition which is excellent in shear adhesive strength and impact adhesive strength, and which can be produced without a complicated process and has excellent storage stability. To provide.

[0006]

Means for Solving the Problems As a result of intensive studies to achieve the above object, the present inventors have found that the degree of crosslinking of the core of the core-shell polymer and the degree of chemical bonding between the core phase and the shell phase (graft rate). However, the present inventors have found that a core-shell polymer in a specific range exhibits remarkable effects such as remarkable improvement in shear adhesive strength and impact adhesive strength of a cyanoacrylate adhesive.

The present invention provides an adhesive composition comprising a cyanoacrylate monomer (a) and a core-shell polymer (b), wherein the core-shell polymer (b) is an acrylic resin.
Together comprising a shell comprising a core and a thermoplastic polymer comprising a beam, is grafted with a polymer molecule constituting the rubber molecules and the shell constituting the core through a grafting agent monomer was copolymerized in a rubber molecule And the crosslinking monomer of the core is 0.2 to 4.0% by weight based on the core, and the grafting agent monomer is 0.2 to 4.0% by weight based on the core.
An adhesive composition used in a range of 5.0% by weight, wherein the core-shell polymer is obtained by emulsion polymerization and separated by a freeze-thaw method in a step of taking out a latex of emulsion polymerization. It is.

Hereinafter, the present invention will be described in detail. The cyanoacrylate monomer, which is the first component of the cyanoacrylate adhesive composition of the present invention, is a compound represented by the following general formula, which is well known as α-cyanoacrylate.

[0009]

Embedded image

In the formula, R is an ester residue such as an alkyl group, a cycloalkyl group, an alkenyl group, a cycloalkenyl group, an alkynyl group, an aryl group, an alkoxyalkyl group and a trialkylsilylalkyl group. Examples of the alkyl group include those having 1 to 8 carbon atoms such as methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, isobutyl, pentyl, hexyl, heptyl and octyl.
Alkyl groups and the like. Preferably, it has 1 carbon atom
-4 lower alkyls. Examples of the cycloalkyl group include cycloalkyl having 3 to 8 carbon atoms such as cyclopropyl, cyclobutyl, cyclopentyl, and cyclohexyl. Examples of the alkenyl group include allyl,
An alkenyl group having 3 to 8 carbon atoms such as isopropenyl, methallyl, 3-butenyl and 3-octenyl is exemplified.

The cycloalkenyl group includes cyclopropenyl, 1-cyclopentenyl, 2-cyclopentenyl, 3-cyclopentenyl, 1-cyclohexenyl,
And cycloalkenyl groups having 3 to 8 carbon atoms, such as -cyclohexenyl, 3-cyclohexenyl, and 3-cycloheptenyl. As the alkynyl group, propargyl,
Alkynyl having 3 to 8 carbon atoms such as 3-hexynyl and 1-octenyl is exemplified. Examples of the aryl group include an aryl group having 6 to 8 carbon atoms such as phenyl, tolyl, and xylyl. Examples of the alkoxyalkyl group include C3-8 alkoxyalkyl groups such as methoxyethyl and ethoxyethyl. Examples of the trialkylsilylalkyl group include trimethylsilylethyl, trimethylsilylpropyl and the like.

[0012] The second component of the cyanoacrylate adhesive composition of the present invention is a thermoplastic polymer ( hereinafter referred to as a thermoplastic polymer) whose core is made of a rubbery polymer and whose shell is also called a glassy polymer.
A core-shell polymer comprising a lower glassy polymer), wherein as a monomer component forming the core, a cross-linking monomer is 0.2 to 4.0% by weight based on the core, and a grafting agent monomer is 0.2% by weight based on the core. Within the range of 2 to 5.0% by weight, and the removal process from the latex of the emulsion polymerization.
Is a core-shell polymer separated by a freeze-thaw method .

The core-shell polymer can be obtained by a continuous multi-stage emulsion polymerization method in which the polymer of the subsequent stage is sequentially subjected to seed polymerization in the presence of the polymer of the previous stage, that is, the so-called multi-stage seed emulsion polymerization method. . Usually, a method of preparing a seed latex by emulsion polymerization, then synthesizing a core portion by seed polymerization, and repeating the seed polymerization to obtain a core-shell polymer is used. Hereinafter, the production of the core-shell polymer will be described in detail.

First, polymerization of the seed particles is carried out by adding a monomer corresponding to the required characteristics all at once. As the monomer, methyl methacrylate and ethyl acrylate are preferably used.

The polymerization of the core is carried out in the presence of a seed latex.
Emulsion polymerization of the monomer forming the rubbery polymer,
This is a polymerization for forming a rubbery polymer having a glass transition temperature of room temperature or lower, preferably -10 ° C or lower, as a polymer constituting the core. When the glass transition temperature of the core is higher than room temperature, the properties as rubber particles may be lost. Here, the glass transition temperature means a peak value temperature of tan δ in dynamic viscoelasticity measurement.

The main component of the monomer forming the rubbery polymer used in the emulsion polymerization of the core is preferably an alkyl acrylate having an alkyl group having 2 to 8 carbon atoms. Examples of the alkyl acrylate having an alkyl group having 2 to 8 carbon atoms include ethyl acrylate, propyl acrylate, butyl acrylate, cyclohexyl acrylate, and 2-ethylhexyl acrylate, and butyl acrylate is particularly preferably used.

In the polymerization of the core, it is particularly preferable to use an alkyl acrylate. In this case, together with the alkyl acrylate, a monomer copolymerizable therewith, for example, aromatic vinyl such as styrene, vinyltoluene and α-methylstyrene; Vinyl cyanide such as aromatic vinylidene, acrylonitrile and methacrylonitrile, vinyl methacrylate, alkyl methacrylate such as methyl methacrylate and butyl methacrylate, or conjugated diene such as butadiene, isoprene and chloroprene can also be copolymerized.

In the present invention, it is essential to use a crosslinkable monomer and a grafting agent monomer as a copolymerization monomer in the polymerization of the core.

Examples of the crosslinking monomer include aromatic divinyl monomers such as divinylbenzene, ethylene glycol diacrylate, ethylene glycol dimethacrylate, butylene glycol diacrylate, hexanediol dimethacrylate, oligoethylene glycol diacrylate, and oligoethylene glycol dimethacrylate. , Trimethylolpropane diacrylate, trimethylolpropane dimethacrylate, trimethylolpropane triacrylate, alkane polyol polyacrylate such as trimethylolpropane trimethacrylate or alkane polyol polymethacrylate. Diol diacrylate is preferably used.

Each of such crosslinkable monomers is used in an amount of 0.2 to 4.
0% by weight, preferably in the range of 0.5 to 2.0% by weight.

The degree of chemical bonding between the core phase and the shell phase is controlled.
Examples of the grafting agent monomer used for the preparation include allyl acrylate, allyl methacrylate, diallyl maleate, diallyl fumarate, and unsaturated carboxylic acid allyl esters such as diallyl itaconate. It is preferably used.

Such graft monomers are each used in an amount of 0.2 to 0.2% of the total amount of monomers used in the polymerization of the core.
It can be used in a range of 5.0% by weight, preferably 0.5 to 4.0% by weight.

When the crosslinking monomer and the graft monomer are out of the above ranges, the reproducibility of the effect of improving the adhesive performance may be deteriorated.

Preferably, the rubbery polymer core is in the range of 50-90% by weight of the total core-shell polymer. When the amount of the core is less than 50% by weight, the effect of improving the adhesive performance may be insufficient.

On the other hand, when the content of the core exceeds 90% by weight, the shell cannot completely cover the core, and the core-shell polymers are fused and aggregated with each other. As a result, the reproducibility of the effect of improving the adhesive performance is poor. May be.

In the production of the core-shell polymer, as a polymerization initiator used for emulsion polymerization of the above-mentioned monomer, a persulfate polymerization initiator such as sodium persulfate and potassium persulfate, azobisisobutyronitrile, 2,2 ′ Azo polymerization initiators such as azobis (2-amidinopropane) dihydrochloride, 2,2'-azobis (2- (2-imidazolin-2-yl) propane, dimethyl methylpropaneisobutyrate;
Organic peroxide initiators such as cumene hydroperoxide and diisopropylbenzene hydroperoxide can be mentioned. Examples of the surfactant used for polymerization include anionic surfactants such as sodium dodecylbenzenesulfonate and sodium dioctyl sulfosuccinate; and nonionic surfactants such as polyoxyethylene nonylphenyl ether and polyoxyethylene monostearate. Can be mentioned.

Next, the shell phase made of a glassy polymer is prepared by preparing a core latex as described above, and then polymerizing a monomer forming the glassy polymer in the presence of the core latex, so that the glass transition temperature is not lower than room temperature, preferably Can be produced by forming a glassy polymer of 60 ° C. or higher on the outermost shell.

As the monomer forming the glassy polymer, methyl methacrylate or styrene, and a monomer copolymerizable therewith are preferably used.

Examples of monomers copolymerizable with methyl methacrylate include alkyl acrylates such as ethyl acrylate and butyl acrylate, alkyl methacrylates such as ethyl methacrylate and butyl methacrylate, aromatic vinyls such as styrene, vinyl toluene and α-methyl styrene. Examples thereof include vinyl cyanide such as aromatic vinylidene, acrylonitrile, and methacrylonitrile, and vinyl polymerizable monomers such as vinylidene cyanide. Ethyl acrylate, styrene, and acrylonitrile are particularly preferably used. As monomers copolymerizable with styrene, for example, methyl acrylate,
Alkyl acrylates such as ethyl acrylate, methyl methacrylate, alkyl methacrylates such as ethyl methacrylate, vinyl toluene, aromatic vinyls such as α-methylstyrene, aromatic vinylidene, acrylonitrile, vinyl cyanide such as methacrylonitrile, vinylidene cyanide and the like Examples thereof include a vinyl polymerizable monomer, and particularly preferably, methyl methacrylate and acrylonitrile are used.

In the polymerization of the shell, a higher adhesive strength may be obtained by using a small amount of a crosslinkable monomer as a copolymerizable monomer. In that case, as the crosslinkable monomer, the monomer used in the polymerization of the core was 4.0% by weight of the total amount of the monomers used in the polymerization of the shell.
When used in the following range, the effect may be large.

This shell phase is preferably present in the range of 10 to 50% by weight of the whole core-shell polymer.
If the outermost shell phase is less than this polymerization range, the shell cannot completely cover the core, and the core-shell polymers will fuse and agglomerate with each other, resulting in poor reproducibility of the adhesive performance improvement effect. Sometimes.

When the shell phase exceeds 50% by weight,
The effect of improving the adhesive performance of the adhesive obtained by adding the produced core-shell polymer may be insufficient.

In the core-shell polymer of the present invention,
There may be several polymerization phases, or mesophases, between the core and the final polymerization phase or shell or between the seed and the core. Such mesophases are formed after the seed or core is formed, for example, a polymerizable monomer having a functional group such as glycidyl methacrylate or unsaturated carboxylic acid, a polymerizable monomer forming a glassy polymer such as methyl methacrylate, butyl acrylate, etc. Such a polymer can be formed by appropriately selecting a polymerizable monomer or the like that forms a rubbery polymer and subjecting it to emulsion polymerization.

The composition of the polymer constituting such an intermediate phase can be variously selected depending on the desired properties of the core-shell polymer.

The polymerization ratio of the intermediate phase can be appropriately determined depending on the characteristics of the intermediate phase as a polymer, that is, the monomers used. For example, when a glassy polymer is used as the intermediate phase, the polymerization ratio may be calculated as a part of the shell, and when a rubbery polymer is used, the polymerization ratio may be calculated as a part of the core.

The structure of the core-shell polymer having such an intermediate phase is such that, for example, when the intermediate phase is polymerized between the core and the shell, another layer, that is, an intermediate layer exists between the core and the shell. Examples thereof include those having a multilayered structure and those having a so-called salami structure, which refers to a structure in which the intermediate phase is dispersed as several granular domains inside the core and the core and the intermediate phase are combined. In the more extreme case of a core-shell polymer having a salami structure, the mesophase to be dispersed may form a new core in the center of the core. The core-shell polymer having such a structure may occur when a monomer represented by styrene is used as a monomer constituting the intermediate phase. The polymerization of the shell phase and the intermediate phase is also carried out using the same polymerization initiator and surfactant as the core.

The core-shell polymer used in the present invention exerts a particularly remarkable effect by producing a latex by the above-mentioned seed emulsion polymerization method while satisfying the above conditions, and then removing the latex from the latex by a freeze-thaw method. It will be.

That is, the latex obtained as described above is
After freezing in an atmosphere of 5-40 ° C, 15-60 ° C
And then dehydrated, and then 40-80
Dry at ℃ to obtain a powder.

By such a powder removing operation, much of the solvent, surfactant and the like used during the emulsion polymerization can be removed.

The particle size of the core-shell polymer thus produced is not particularly limited, but is usually 100 to 100.
0 nm (0.1-1 μm), preferably 120-750
nm.

The core-shell polymer taken out as described above has an effect of giving a composition having excellent storage stability even though the treatment for removing impurities has not been performed. According to the disclosure of the above-mentioned U.S. Pat. No. 4,560,723, ionic impurities may remain in the core-shell polymer and the storage stability of the composition may be reduced. When the core-shell polymer of the invention is used, the storage stability of the composition is maintained at a high level.

The cyanoacrylate adhesive composition according to the present invention is based on 100 parts by weight of cyanoacrylate.
It is usually obtained by adding 3 to 30 parts by weight, preferably 5 to 20 parts by weight of the core-shell polymer.
If the amount of the core-shell polymer is less than 3 parts by weight, the effect of improving the adhesive performance of the obtained adhesive composition cured product may not be recognized. If the amount is more than 30 parts by weight, the obtained adhesive composition cured product May be significantly impaired in rigidity and heat resistance.

The cyanoacrylate-based adhesive composition according to the present invention can be easily prepared by adding a predetermined amount of the core-shell polymer to cyanoacrylate and stirring for several hours while heating at 40 to 60 ° C.

Further, the adhesive composition according to the present invention comprises a thickener, a filler, a bulking agent, a crosslinking agent, an anionic polymerization inhibitor,
An appropriate amount of a known additive for cyanoacrylate-based adhesives such as a radical polymerization inhibitor, an adhesion improver, a heat resistance improver, a water resistance improver, a curing accelerator, and a colorant can also be added.

[0045]

Industrial Applicability The cyanoacrylate adhesive composition of the present invention has excellent effects of shear adhesive strength and impact adhesive strength and can be used as a household or industrial instant adhesive.

[0046]

The present invention will be described below with reference to examples and comparative examples, but the present invention is not limited to these examples.

In the examples and comparative examples, “parts” and numerical values in the tables represent parts by weight. Abbreviations used in Examples and Comparative Examples are as follows. * Cyanoacrylate Methyl α-Cyanoacrylate MCA Ethyl α-Cyanoacrylate ECA Allyl α-Cyanoacrylate ACA Ethoxyethyl α-Cyanoacrylate EECA * Persistant Diphenylmethane DPM * Monomer Butadiene Bd 2-Ethylhexyl acrylate 2EHA n-Butyl acrylate BA Methyl methacrylate MMA Ethyl acrylate EA Acrylonitrile AN Styrene St Allyl methacrylate AlMA 1,4-butylene glycol diacrylate BGA Divinylbenzene DVB * Surfactant Daiichi Kogyo Seiyaku (manufactured) Neocor P NP (sodium dioctyl sulfosuccinate) Kao Perex SSL SSL (Sodium alkyl diphenyl ether disulfonate) * Others On water DIW Sodium bicarbonate SBC Sodium persulfate SPS

[Test Method] * Measurement of Weight Average Particle Size The weight average particle size of the core-shell polymer was measured by LPA-3000 manufactured by Otsuka Electronics Co., Ltd.

* Shear Bond Strength Tensile shear bond strength was measured according to JIS K6861. The test piece was degreased 100 × 25 × 1.6 m
Using a cold rolled steel plate (SPCC-SD), the welded portion (10 × 25 mm) is polished and washed with # 240 sandpaper, the adhesive is applied to the adhesive portion, and the test pieces are overlapped and fixed with clips. , 24 ± 1 ° C., 55 ± 5 RH% for 24 hours for adhesion. The shear bond strength was Tensilon, and the maximum load at break was measured at a pulling rate of 10 mm / min.

* Impact adhesive strength Impact adhesive strength was measured according to JIS K 6855. 40 × 25 × 20mm and 25 × 12.5 × 10mm
Of the two types of iron test specimens, the adhesive surface of each of test specimen-1 and test specimen-2 was polished and washed with sandpaper # 240, and the adhesive surface of test specimen-2 (25 × 12.5 mm )
After applying an adhesive to the test piece 1, the test piece 2 was overlaid on the test piece 1, and the test piece 2 was fixed with a weight of about 170 g, and allowed to stand for 24 hours in an environment of 24 ± 1 ° C. and 55 ± 5 RH% for bonding. The impact adhesive strength is
It was measured with an impact tester manufactured by Toyo Seiki Seisaku-sho, Ltd.

Example 1: Preparation of core-shell polymer A and preparation of cyanoacrylate adhesive composition DIW 427.5 g with 10 liter reflux condenser, 1% N
An aqueous P solution (10.8 g) and a 1% SBC aqueous solution (72.5 g) were charged and heated to 70 ° C. while stirring under a nitrogen stream. E
After adding 36.0 g of A and dispersing for 10 minutes,
18.0 g of a 2% aqueous SPS solution was added, and the reaction was carried out under stirring for 1 hour. Finally, it was diluted with 1980 g of DIW to obtain a seed latex.

Subsequently, at 70 ° C., 300.0 g of a 2% aqueous SPS solution was added, and the following monomer emulsion 4314.
After continuously feeding 0 g over 240 minutes, the mixture was heated to 90 ° C. and subjected to an aging reaction for 1 hour to obtain a core latex.

First-stage monomer emulsion 2889.9 g BA 14.8 g BMA 59.3 g 1% NP 1050.0 g 1% SBC 150.0 g DIW 150.0 g

Next, the mixture was cooled to 70 ° C. to polymerize the shell. After adding 100.0 g of a 2% SPS aqueous solution and continuously feeding 1800.0 g of the following monomer emulsion over 180 minutes, the mixture was heated to 90 ° C. and subjected to an aging reaction for 1 hour.

Second-stage monomer emulsion MMA 995.0 g BGA 5.0 g 1% NP 400.0 g 1% SBC 100.0 g DIW 300.0 g

After completion of the ripening, the mixture was cooled to 30 ° C., filtered through a 300-mesh stainless steel wire gauze, and extracted with a weight average particle size of 542.
nm of core-shell polymer latex was obtained.

This latex was once frozen at -30 ° C., thawed, dehydrated and washed with a centrifuge, and dried by blowing air at 60 ° C. overnight to obtain a core-shell polymer A.

The cyanoacrylate adhesive composition was prepared as follows. EC in 500ml beaker
A was weighed out in an amount of 300 g, and the stirring blade was rotated at 300 rPm by a three-one motor. After 30 g of the core-shell polymer A was added thereto, the temperature was adjusted to 50 ° C. with a heater, and the mixture was stirred for 4 hours. Thereafter, the heating was stopped, and the mixture was further stirred for 4 hours while being left to cool to room temperature, thereby obtaining a cyanoacrylate adhesive composition.

Examples 2 and 3: Preparation of cyanoacrylate adhesive composition of core-shell polymer A The same operation as in Example 1 was carried out with the composition shown in Table 2,
A cyanoacrylate-based adhesive composition was obtained.

Examples 4 to 6: core-shell polymer B,
Production of C and D and Preparation of Cyanoacrylate Adhesive Composition The same operation as in Example 1 was performed using the monomer compositions shown in Table 1 to obtain core-shell polymers B, C, and D. Then, Table 2
The same operation as in Example 1 was carried out using the composition shown in (1) to obtain a cyanoacrylate adhesive composition.

Examples 7 to 9: Preparation of cyanoacrylate adhesive composition of core-shell polymer A In the composition shown in Table 2, MCA and A were used instead of ECA.
The same operation as in Example 1 was performed using CA and EECA,
A cyanoacrylate-based adhesive composition was obtained.

Comparative Examples 1-4: Adhesion strength of various cyanoacrylates ECA, MCA, ACA and EECA as blanks
Was measured for shear bond strength and impact bond strength.

Comparative Example 5 Production of Core-Shell Polymer E and Preparation of Cyanoacrylate Adhesive Composition The same operation as in Example 1 was carried out using the monomer compositions shown in Table 1 to obtain a core-shell polymer E. Subsequently, the same operation as in Example 1 was performed using the composition shown in Table 2 to obtain a cyanoacrylate-based adhesive composition.

Comparative Examples 6 and 7: Core-shell polymer KM3
30, dispersion of BTA751 in ECA KM330 (acrylic core-shell polymer, manufactured by Rohm & Haas Co.) and BTA751 (MBS core-shell polymer, manufactured by Kureha Chemical Industry Co., Ltd.), each having the composition shown in Table 2 The same operation as in Example 1 was performed. Within 30 minutes after adding and adjusting the temperature of each core-shell polymer, the temperature of the solution rapidly increased, and the ECA gelled.

Comparative Example 8: Preparation of Cyanoacrylate Adhesive Composition of Persistant DPM In the composition shown in Table 2, DPM as a sustaining agent was subjected to ECA.
And dissolved at room temperature with stirring.

Comparative Example 9: Preparation of a cyanoacrylate-based adhesive composition of core-shell polymer C and a preservative DPM In a composition shown in Table 2, DPM as a preservative was subjected to ECA.
And dissolved at room temperature with stirring. Then, Table 2
A predetermined amount of core-shell polymer C is formulated in the composition shown in EC
A and the same operation as in Example 1 was carried out to obtain a cyanoacrylate-based adhesive composition.

[0067]

[Table 1]

[0068]

[Table 2]

Continuation of the front page (72) Inventor Junji Oshima 3-10-8 Ueno Higashi, Toyonaka City, Osaka Prefecture (56) References JP-A-2-311583 (JP, A) JP-A-53-30643 (JP, A) JP-A-47-51807 (JP, A) JP-A-62-25185 (JP, A) JP-A-59-74176 (JP, A) JP-A-3-290484 (JP, A) JP-A-6-240209 (JP, A) JP 5-59949 (JP, B2) (58) Fields investigated (Int. Cl. ⁷ , DB name) C09J 1/00-201/10 CA (STN) REGISTRY (STN)

Claims (6)

(57) [Claims] 1. An adhesive composition comprising a cyanoacrylate monomer (a) and a core-shell polymer (b), wherein the core-shell polymer (b) comprises an acrylic rubber.
A core and a shell made of a thermoplastic polymer, and a rubber molecule constituting the core and a polymer molecule constituting the shell are graft-bonded via a grafting agent monomer copolymerized in the rubber molecule. 0.2 to 4.0% by weight of the crosslinking monomer of the core with respect to the core, and 0.2 to 5.0% by weight of the grafting agent monomer with respect to the core.
Wherein the core-shell polymer is obtained by emulsion polymerization and is separated by a freeze-thaw method in a step of taking out a latex of the emulsion polymerization. 2. The adhesive composition according to claim 1, wherein the core-shell polymer is present in an amount of 3 to 30 parts by weight based on 100 parts by weight of the cyanoacrylate monomer. 3. The adhesive composition according to claim 1, wherein the constituent monomer of the acrylic rubber is an alkyl acrylate having 2 to 8 alkyl carbon atoms. 4. The adhesive composition according to claim 1, wherein the grafting agent monomer is an unsaturated carboxylic acid allyl ester. 5. The adhesive composition according to claim 1, wherein the crosslinking monomer is used in an amount of 4.0% by weight or less in the shell of the core-shell polymer. 6. The glass transition temperature of the core acrylic rubber is
Below −10 ° C., the shell thermoplastic polymer
The transition temperature is 60 ° C. or higher.
2. The adhesive composition according to 1.