JPH0713217B2 - Adhesion method to alkaline substrate - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial field of application> The present invention relates to an adhesion method for attaching a decorative material or a heat insulating material to the surface of an alkaline substrate.

<Prior art> To attach an adherend such as wallpaper or felt to an alkaline substrate such as asbestos slate board or silica board, use an elastomer adhesive such as solvent-type or water-dispersion type chloroprene rubber. Adhesive method to apply and stick to both adherends. Alternatively, an adhesive method has been employed in which an epoxy-based or vinyl acetate-based synthetic resin adhesive is applied to one of the adhesive surfaces and then bonded. Solvent-type elastomer adhesives have excellent initial strength, but there is a risk of fire and pollution due to organic solvents, and water-dispersed adhesives exhibit slow initial strength upon drying and solidification. There is inconvenience to apply to. Further, since the synthetic resin adhesive is wet-adhering, it takes time until the initial strength is exhibited by dry curing, and the efficiency of the adhering work is poor.

<Problems to be Solved by the Invention> The present invention solves the above-mentioned drawbacks of the prior art, and provides a water-dispersible adhesive that can be adhered even by single-sided application and has a high initial strength. It is a thing.

<Means for Solving Problems> The present invention is an aqueous dispersion of a synthetic resin or an elastomer having a pH value of 7 or less, and an alkali thickening type having a carboxyl group content of 0.5 to 25% by weight in terms of solid content. This is an adhesive method in which an adhesive is applied to the surface of an alkaline substrate and another adherend is attached to the applied surface before solidification.

The alkaline base material to be bonded in the present invention, concrete blocks of buildings, PC board, ALC board, ceramic products molded aggregates and fibers using cement as a binder, such as slate board, calcium silicate , Magnesium carbonate,
A porous inorganic base material having a pH value of 7 or more on the adhesive surface, such as a whitewashed white wall, is applied. Other materials to be adhered include wall covering materials, decorative materials, heat insulating materials made of glass fibers and foams, wood building materials such as plywood and hardboard, and ceramic building materials such as those mentioned above, which are lightweight and porous. Suitable for dressing.

Next, as the alkali-thickening adhesive used in the present invention, ethylene-vinyl acetate copolymer emulsion, acrylic ester resin emulsion or other synthetic resin emulsion production, or chloroprene latex or acrylonitrile-butadiene copolymerization A known monomer obtained by emulsion copolymerization by adding a polymerizable monomer having a carboxyl group (eg, α, β-unsaturated carboxylic acid) such as acrylic acid or methacrylic acid at the time of producing an elastomer latex such as a rubber latex. Of these, in the present invention,
A rosin as a known tack-free agent, which has a pH value of 7 or less and a carboxyl group content of 0.5 to 25% by weight in terms of solid content as a main component of an aqueous dispersion of a resin or an elastomer, An adhesive having a solid content of 20 to 70%, which is prepared by blending a petroleum resin, an alkylphenol resin or the like, or added with a crosslinking agent such as an epoxy compound reactive with a carboxyl group or a compound having an aziridine ring, is suitable.

Next, as a method for applying the adhesive to the alkaline substrate, a known applicator or application method such as a brush, a roller, or a spray is applied at 25 to 200 g / m ^{2 in} terms of solid content, but a non-porous material. A small amount may be applied to the base material, but a large amount is applied to a porous substrate.

<Operation> In the present invention, the alkaline thickening adhesive is basically applied to an alkaline substrate, but the effect is that a part of the water content in the adhesive is an alkaline substrate on the adhesive coated surface. The pH value of the water in the emulsion of the adhesive layer rises to 7 or more due to the alkalinity of the base material, and the carboxyl groups in the adhesive swell and the viscosity is remarkably increased. For this reason,
An adhesive layer having a sufficiently high viscosity required for temporarily fixing other adherends is formed to accelerate the development of initial adhesive strength. After the bonding, the moisture permeates and diffuses into the base material and the adherend, volatilizes to form a film, and exhibits adhesive strength. With respect to this action, with an adhesive having a carboxyl group content in the resin or elastomer of 0.5% by weight or less in terms of solid content, no increase in viscosity immediately after application is observed and the initial adhesive strength is not expressed. Also,
When it is 25% by weight or more, the water-resistant adhesive strength is lowered.

Next, an example will be described.

Example 1. An acrylic resin emulsion having a pH value of 4.5 and a solid content of 50%, and an alcal thickening adhesive having a carboxyl group content of 5% by weight in terms of solid content was sprayed on an asbestos cement board having a pH value of 11. At a rate of about 150 g / m ² , apply glass fiber immediately after application, and immediately after pressing with a compression roller and 3
After 180 days, the 180 ° peeling adhesive strength was measured.

Comparative Example 1. The solid content of Example 1 containing no carboxyl group and having a pH value of 4.
The same procedure was performed except that a 50% acrylic resin emulsion was used.

Comparative Example 2. The same procedure as in Example 1 was repeated except that plywood was used instead of the asbestos cement board.

These measured values are shown in Table 1.

<Effect> As described above, in the mounting method of the present invention, the initial adhesive force and the temporal adhesive force immediately after application are excellent despite the one-side application, and therefore the efficiency of the adhesive work is promoted.

Claims (1)

[Claims] 1. An aqueous dispersion of a synthetic resin or an elastomer having a pH value of 7 or less on the acidic side, and an alkali thickening adhesive having a carboxyl group content of 0.5 to 25% by weight in terms of solid content is used as an alkaline group. A method for adhering to an alkaline substrate by single-sided application, which comprises applying the adhesive to one side of a material surface and sticking the other adherend to which the adhesive has not been applied to the applied surface before solidification.