JPH09183950A - Two-pack acrylic adhesive composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a two-pack acrylic adhesive composition improved in adhesive performances, especially peeling strength at ordinary temperature by adding a specified compound to a two-pack acrylic adhesive composition having a specified structure. SOLUTION: This two-pack acrylic adhesive composition comprises composition A containing at least one (meth)acrylic ester, an ethylene acryl rubber and an organic peroxide (e.g. cumene hydroperoxide) which generates radicals and thereby polymerizes the (meth)acrylic ester and composition B containing at least one (meth)acrylic ester, an ethylene/acryl rubber and a reducing agent (e.g. benzoylthiourea) which accelerates the decomposition of the organic peroxide to allow it to generate radicals. Compositions A and/or B should further contain an N-substituted maleimide compound (e.g. N-cyclohexylmaleimide).

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement in a radical-polymerizable two-component non-mixing acrylic adhesive composition.

[0002]

BACKGROUND OF THE INVENTION Two-component acrylic adhesives can be used as two-component non-mixing type adhesives, eliminating the need for pre-mixing of the adhesives and facilitating the bonding work. The curing reaction time is short, and the rubber adhesive does not need a solvent, and the curing speed is fast, while it cures after waiting for the solvent contained in the component to evaporate. On the other hand, the one-pack type anaerobic acrylic adhesive There is no inconvenience that the air contact part does not harden, and it has a wide range of uses. Therefore, the two-component acrylic adhesive can be rationalized and speeded up in the bonding work, has high reliability for the bonded portion, and is widely used.

Further, in order to make the two-component acrylic adhesive resistant to adhesion under severe conditions, in order to make the adhesive excellent in tensile shear strength and peeling strength after heat aging, the present applicant has Have already proposed an adhesive composition containing ethylene acrylic rubber as one component (Japanese Patent Publication No. 60-31).
873). Although this prior invention has made it possible to cope with the heat aging of the above adhesive by the addition of ethylene acrylic rubber, the present invention further increases the initial adhesive performance, particularly the peel strength at room temperature, It is intended to provide a more reliable two-component acrylic adhesive that can maintain the initial adhesive performance for a long period of time.

[0004]

The present invention includes a composition A in which a monomer of (meth) acrylic acid ester contains organic peroxide and ethylene acrylic rubber, and a (meth) acrylic acid ester contains a reducing agent and ethylene acrylic rubber. Composition B, and
A two-component acrylic adhesive comprising
At least one of B and N-substituted maleimide compound is contained, and the peel strength of the adhesive layer at room temperature is increased by the N-substituted maleimide compound.

[0005]

BEST MODE FOR CARRYING OUT THE INVENTION Both Composition A and Composition B contain a monomer or oligomer of (meth) acrylic acid ester as a base for reaction curing of an adhesive. In this specification, the term "(meth) acrylic acid ester" is a concept including both acrylic acid ester and methacrylic acid ester. The (meth) acrylic acid ester includes methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, butyl (meth) acrylate, (meth)
2-hydroxyethyl acrylate, 2-hydroxypropyl (meth) acrylate, (meth) acrylic acid-2
-Ethylhexyl, glycidyl (meth) acrylate,
Mono (meth) acrylates such as benzyl (meth) acrylate, phenoxyethyl (meth) acrylate, and tetrahydrofurfuryl (meth) acrylate can be appropriately used, and also polyester (meth) acrylate, polyether (meth) Oligo (meth) acrylates such as acrylates, epoxy (meth) acrylates, urethane (meth) acrylates, and other (meth) acrylic modified polymers are used, and one or more of these (meth) acrylic acid esters are used. To be done.

Composition A contains an organic peroxide and an ethylene acrylic rubber in one or more of the above (meth) acrylic acid esters, but the organic peroxide in Composition A generates radicals to generate the radicals described above ( (Meth) Acrylic ester is vinyl-polymerized and cured, and is adopted from hydroperoxide, alkyl peroxide, diacyl peroxide, ketone peroxide, and the like.
Cumene hydroperoxide, t-butyl hydroperoxide, paramenthane hydroperoxide,
Methyl ethyl ketone peroxide, cyclohexanone peroxide, dicumyl peroxide, benzoyl peroxide and the like are preferably used. The content of these organic peroxides in the composition A is preferably 0.1 to 10% (weight%, the same applies hereinafter). When the content of the organic peroxide exceeds 10%, the storage stability of the composition A is deteriorated and the composition A is 0.1%.
If it is less than 1, the curing reaction will not be sufficient.

The composition B comprises one or more of the above (meth) acrylic acid ester and a reducing agent and an ethylene acrylic rubber. The reducing agent in the composition B is
When the composition B and the composition A are contact-mixed with each other, the decomposition of the organic peroxide is promoted to rapidly generate radicals to start the polymerization reaction of the (meth) acrylic acid ester. , Thiourea compounds, metal chelate compounds,
Metal soaps, tertiary amines, polyamines, mercaptans, etc. can be used. The content of the reducing agent in the composition B is 0.0
It is in the range of 5 to 10%. If it is less than 0.05%, the polymerization and curing rate will be slow, and if it is more than 10%, the adhesive strength will be reduced.

Both composition A and composition B contain ethylene acrylic rubber, which is
The compositions A and B are given an appropriate viscosity to improve the adhesive strength such as impact strength and peel strength of the cured adhesive layer. Ethylene acrylic rubber is a copolymer of ethylene, acrylic acid, and acrylic acid ester, and exhibits rubber elasticity at room temperature. As the ethylene acrylic rubber, an ethylene-acrylic acid-methyl acrylate copolymer is particularly preferable as shown in Chemical formula 1, and this ethylene acrylic rubber is available as "Baymac" manufactured by DuPont.

[0009]

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The content of ethylene acrylic rubber in each of Composition A and Composition B is in the range of 5 to 50%, preferably 5 to 30%. When it exceeds 50%, the composition becomes highly viscous and the handling of the adhesive is inconvenient, and when it is less than 5%, the adhesive strength decreases. Ethylene acrylic rubber is partially substituted by other rubbers such as acrylonitrile-butadiene rubber (NBR) and methyl methacrylate-butadiene-
It can be replaced by a styrene copolymer (MBS resin).

The adhesive composition of the present invention is characterized in that an N-substituted maleimide compound is added to at least either composition A or composition B as described above. It enhances the peel strength of the cured adhesive layer at room temperature, and N-cyclohexylmaleimide, N-phenylmaleimide, N-butylmaleimide, N-isopropylmaleimide, N-laurylmaleimide, etc. are effective as N-substituted maleimide compounds. Is. The N-substituted maleimide compound is appropriately added in an amount of 0.5 to 30 parts by weight based on 100 parts by weight of composition A or composition B to be added. If the amount of maleimide added is less than 0.5 parts by weight, the effect of improving room temperature peel strength is poor, and if added in excess of 30 parts by weight, further improvement in peel strength cannot be expected and the adhesive surface tends to become hard. .

Compositions A and B having the above-mentioned composition further include quinone type stabilizers such as hydroquinone and benzoquinone, antioxidants, fillers for adjusting viscosity and increasing the amount, pigments for coloring, surface hardening. Waxes and other additives for improving the properties may be contained. The adhesive finally composed of the composition A and the composition B thus prepared is used as a two-component non-anaerobic adhesive. That is, when the adhesive is used, the composition A and the composition B can be used both as a mixed type and as a non-mixed type.
The composition A and the composition B are separately applied to the adherends of the two adherends to be adhered without premixing, and then the composition A is obtained.
The one adhesive surface coated with and the other adhesive surface coated with the composition B are brought into face-to-face contact and pressed, and the adhesive layer is polymerized and cured by mixing the two compositions at the time of pressing, so that the adherends firmly adhere to each other. It comes to adhere. Since such an adhesive has heat aging prevention by ethylene acrylic rubber and room temperature peel strength by N-substituted maleimide, it is particularly preferable to use metal, metal oxide,
Suitable for bonding polar plastics, wood, concrete, ceramics, etc.

[0013]

【Example】

(1) Preparation of Adhesive In a flask equipped with a stirrer, a condenser and a thermometer, 38 parts of methyl methacrylate (parts by weight, the same applies hereinafter), 14 parts of 2-hydroxyethyl methacrylate, and methacrylic acid-
14 parts of 2-ethylhexyl were charged, and ethylene acrylic rubber (“Baymac N-123” manufactured by DuPont) was added to this.
20 parts and 1 part of paraffin were added and dissolved at 70 ° C. with stirring. The solution was divided into two, 6% of cumene hydroperoxide (wt%, the same applies hereinafter) was added to one of the solutions to prepare solution A, and 2% of benzoylthiourea and 4% of methacrylic acid were added to the other solution. To prepare a liquid B.

N-cyclohexylmaleimide (CHMI), N-phenylmaleimide (PMI), N-containing N-substituted maleimide compounds are used in both liquids A and B.
-Lauryl maleimide (LMI) was added as shown in Table 1 to prepare a sample for peel strength test. The addition amount in Table 1 is
It is shown as parts by weight of N-substituted maleimide with respect to 100 parts by weight of solution A or solution B. As a comparative example, solutions A and B to which no N-substituted maleimide compound was added were also used.

(2) Peel strength test The test piece consists of two steel plates (steel type SPCC-SB, length 15).
The plate surface was air blasted with 0 mm, width 25 mm, and thickness 0.3 mm), and then degreased with acetone to form an adhesive surface. The above-mentioned liquid A was applied to the adhesive surface of one steel plate, the above-mentioned liquid B was applied to the adhesive surface of the other steel plate, the applied surfaces were superposed, and the steel plate test piece was adhered. After leaving the bonded test piece at room temperature for 24 hours, at 23 ° C. and 50% RH,
JIS T-type peel strength under the condition of pulling speed 250mm / min
It measured based on K6854. The results of the peel strength test are summarized in Table 1.

[0016]

[Table 1]

From Table 1, in comparison with the adhesive of sample No. 12 of the comparative example, N- with the ethylene acrylic rubber of the example.
Adhesives containing a substituted maleimide compound (Sample Nos. 1 to 1
In 11), it can be seen that the peel strength at room temperature is improved.

Claims (3)

[Claims] 1. A composition A containing an ethylene acrylic rubber and an organic peroxide which generates a radical in at least one of (meth) acrylic acid ester to polymerize the (meth) acrylic acid ester, and (meth ) A composition B containing a reducing agent that promotes decomposition of the organic peroxide to generate a radical in one or more acrylates and ethylene acrylic rubber, and an acrylic adhesive composition comprising: At least one of the composition A and the composition B,
A two-pack type acrylic adhesive composition containing an N-substituted maleimide compound. 2. The two-component acrylic adhesive according to claim 1, wherein the amount of the N-substituted maleimide compound added is 0.5 to 30 parts by weight with respect to 100 parts by weight of the composition A or composition B. Agent composition. 3. An organic peroxide of 0.1 to 10% by weight and an ethylene acrylic rubber of 5 to 50% by weight, wherein radicals are generated in one or more kinds of (meth) acrylic acid ester to polymerize the (meth) acrylic acid ester. Composition A containing and
And a reducing agent 0.05 to 10% by weight and a ethylene acrylic rubber 5 to 50 which accelerates the decomposition of the organic peroxide to generate radicals in one or more (meth) acrylic acid esters.
% Of the composition B, and at least one of the above composition A and the composition B,
A two-component acrylic adhesive composition, wherein 0.5 to 30 parts by weight of an N-substituted maleimide compound is added to 100 parts by weight of the composition.