JPH09157617A - Aqueous adhesive - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an aqueous adhesive having an improved initial adhesivity by combining a vinyl acetate emulsion using a methyl vinyl ether-maleic anhydride copolymer as a protecting colloid with an aqueous solution of a polyvalent metal salt. SOLUTION: This two-pack type aqueous adhesive is composed of the solution A consisting of a vinyl acetate emulsion using an aqueous solution containing a methyl vinyl ether-maleic anhydride copolymer (e.g. GANTREZ(R) AN-139 produced by G.A.F. Corporation) as a protecting colloid and the solution B consisting of an aqueous solution of a polyvalent metal salt (e.g. zirconium carbonate) capable of reacting with a carboxyl group.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a water-based adhesive which exhibits extremely high adhesive strength in a short time and has excellent heat resistance.

[0002]

2. Description of the Related Art Conventionally, as an adhesive or an adhesive, an organic solvent was used as a medium, but one or both of adherends are water-permeable from the viewpoint of safety, hygiene, resource saving, and no pollution. In the case of a certain material, an aqueous adhesive, especially an emulsion adhesive has come to be used frequently. However, there is a fatal drawback that the initial adhesive force is extremely slow to develop due to poor drying property due to the medium being water.

In order to remedy these drawbacks, a two-component type initial adhesive is used in which an aqueous adhesive containing rubber latex as a main component is combined with a film-forming agent, or an emulsion type aqueous adhesive is combined with an adhesion promoter. A method of expressing sex has also been proposed.

[0004]

Generally, salting out may occur when an aqueous solution of a metal salt or the like is added to an aqueous polymer emulsion, and when a certain organic solvent or an ion of opposite charge is added. It is well known that emulsions agglomerate. The above method focuses on the aggregation characteristics of such emulsions, but in reality, the situation significantly differs depending on the type of emulsion. For example, among the emulsions used in this method, no salting out or agglomeration occurs at all, or even if they occur, the adhesiveness to the adherend is extremely reduced and the function thereof is not fulfilled, or the drying is deteriorated. On the contrary, there was a problem that the initial adhesiveness was lowered.

An object of the present invention is to provide an aqueous adhesive having excellent initial adhesiveness and heat resistance.

[0006]

Means for Solving the Problems The present invention provides the following (A),
An aqueous adhesive comprising the two liquids of (B). (A) A vinyl acetate emulsion using an aqueous solution containing a methyl vinyl ether-maleic anhydride copolymer as a protective colloid, and (B) an aqueous solution of a polyvalent metal salt capable of reacting with a carboxyl group.

In the water-based adhesive of the present invention, the main component (A)
The methyl vinyl ether-maleic anhydride copolymer constituting the protective colloid in the liquid is, for example, a commercially available product G.
A. F Corporation's GANTREZ AN copolymer series, low molecular weight GANTREZ A
N-119 to high molecular weight grade GANTREZAN
There are up to -169.

The protective colloid is prepared by adding a methyl vinyl ether-maleic anhydride copolymer alone or in combination with a commonly used polyvinyl alcohol (PVA) into water and dispersing the mixture. And dissolve. In addition, an alkaline component such as caustic soda or aqueous ammonia may be used to accelerate the dissolution rate.

The vinyl acetate emulsion is a vinyl acetate monomer, or a vinyl acetate monomer and another monomer are emulsion-polymerized by using the above-mentioned protective colloid, and a vinyl acetate emulsion or a copolymer of vinyl acetate and another monomer. It is an emulsion.

Emulsion polymerization can be carried out according to a conventional method,
As the polymerization initiator, for example, persulfate is suitable.
Examples of the other monomer include (meth) acrylic acid, (meth) acrylic acid ester, ethylene, vinyl chloride, and styrene. The viscosity, resin concentration, PH, etc. of the obtained emulsion are not limited and can be appropriately changed depending on the bonding method, the adhesive composition coating device, and the like.

The mixing ratio of the methyl vinyl ether-maleic anhydride copolymer in the vinyl acetate emulsion is 100 parts by weight of the vinyl acetate resin, based on 100 parts by weight of the vinyl acetate resin. 5 to 20 parts of copolymer are suitable. If it is 5 parts or less, the effect of the present invention cannot be obtained, and if it is 20 parts or more, the cost becomes high.

Next, as the polyvalent metal salt capable of reacting with the carboxyl group constituting the solution (B), calcium, magnesium, zinc, copper, barium, iron, aluminum, zirconium and the like hydrochlorides, sulfates and sulfites. Examples include salts, nitrates, nitrites, phosphates, and carboxylates. These salts may be used alone or may be mixed, but particularly effective are organic metal compounds such as organic titanates, aluminum compounds and zirconium compounds.

The amount of the polyvalent metal salt used is 100 parts by weight of the solid resin content of the vinyl acetate emulsion of the liquid (A).
The solid content is preferably 0.2 to 20 parts by weight. If it is less than 0.2 parts by weight, the effect of the present invention cannot be obtained, and if it exceeds 20 parts by weight, the adhesive strength is significantly lowered, which is not preferable.

As a method of combining the solution (A) and the solution (B), the respective surfaces of the adherends to be adhered may be separately coated, and the surfaces to be coated may be superposed and pressure-bonded,
The liquid (A) and the liquid (B) may be sprayed onto the adherend at the same time and then pressure-bonded, and the effect of the present invention can be exhibited by any method.

The water-based adhesive of the present invention can be used for bonding as it is without any modification. However, depending on the use and purpose, other water-based polymer may be added. Emulsions and tackifiers, inorganic powders such as calcium carbonate and clay, organic extenders such as wheat flour and starch, or solvents, plasticizers, thickeners, defoamers, stabilizers, rust inhibitors, It is also possible to mix and use various additives such as antiseptics, pigments, colorants, and crosslinking agents.

[0016]

Embodiments will be described below with reference to embodiments. Parts are parts by weight. Example 1 Preparation of protective colloid GANTREZAN-139 (GAF Corpo) of a methyl vinyl ether-maleic anhydride copolymer was placed in a reactor.
ration) (18.4 parts) and polyvinyl alcohol DENKA POVAL B05 (manufactured by Denki Kagaku) (1.6 parts) in water 184
The mixture was charged into a part, stirred and dispersed, and then heated and dissolved at 80 to 90 ° C to obtain a protective colloid.

Next, the protective colloid was adjusted to 80 ° C., and 216 parts of vinyl acetate monomer and a polymerization initiator prepared by dissolving 0.6 part of ammonium persulfate in 80 parts of water were simultaneously applied for 3 hours. After dropwise addition for emulsion polymerization and cooling to room temperature, 3.0 parts of soda ash was added for neutralization, and then 10 parts of DBP as a plasticizer was added to prepare a solution A of Example 1. The liquid A had a nonvolatile content of 46% and a viscosity of 2900 cps / 30 ° C.

Example 2 In Example 1, instead of 216 parts of vinyl acetate monomer, 194 parts of vinyl acetate monomer and 2 parts of butyl acrylate were used.
A liquid of Example 2 was obtained in the same manner except that 2 parts of the mixed liquid was used. The liquid A has a nonvolatile content of 46% and a viscosity of 3400c.
It was ps / 30 ° C.

Next, as a polyvalent metal salt capable of reacting with the carboxyl group constituting the solution B, zircosol AC-7 (manufactured by Daiichi Rare Element Chemical Industry Co., Ltd.) in a 13% aqueous solution of zirconium carbonate, mono-sec-butoxyaluminum. Aluminum alkcoat A of 12.4% aqueous solution of diisopropylate
MD (manufactured by Kawaken Fine Chemicals Co., Ltd.), TLA (T of 30.8% dihydroxy-bis (lactate) titanium aqueous solution
ilac) (manufactured by Nippon Soda Co., Ltd.)
Used as B3.

Comparative Example 1 Only the liquid A of Example 1 was used as the adhesive of Comparative Example 1. Comparative Example 2 Only the liquid A of Example 2 was used as the adhesive of Comparative Example 2.

Adhesive force measurement method Using the above-mentioned solutions A and B (B1, B2, B3), JIS
It was measured according to the method described in K-6852 "Test method for compressive shear adhesive strength of adhesive". The adherend is a birch, and the liquid A is applied to the adhesive surface of one of two test pieces of size 25 × 30 × 10 (each mm) (applied amount about 200 g /
m ² ), apply the solution B to the adhesive surface of the other test piece (applied amount about 40 g / m ² ), adhere both surfaces closely, and immediately press (pressing pressure of about 5 kg / cm ² for 5 seconds). did. 5 after decompression
Table 1 shows the results of measuring the compressive shear bond strength after the curing for minutes and after the curing for 24 hours.

Comparative Example 1 was applied to one adhesive surface of the test piece and adhered to the adhesive surface of the other test piece (the solution B was not applied), and then, as in Examples 1 and 2. The measurement was performed after compression and curing.

[0023]

[Table 1] B1: Zircosol B2: AMD B3: TLA

[0024]

As is clear from Table 1, the water-based adhesive of the present invention has excellent initial adhesive strength.

Claims (1)

[Claims] 1. A water-based adhesive comprising the following two liquids (A) and (B). (A) A vinyl acetate emulsion using an aqueous solution containing a methyl vinyl ether-maleic anhydride copolymer as a protective colloid, and (B) an aqueous solution of a polyvalent metal salt capable of reacting with a carboxyl group.