JPH0116873B2 - - Google Patents

Description

[Detailed description of the invention]

By laminating synthetic resin foams such as urethane resin foam, styrene resin foam, vinyl chloride resin foam, polypropylene resin foam, and polyvinyl acetal foam, or by laminating such foams with other flexible materials. Conventionally, organic solvent-based contact cement has been used as flexible foot material for chairs, sofas, beds, mats, and other items. However, in recent years, water-based contact cement, which is harmless and safe, has become popular in place of organic solvent-based contact cement due to concerns about air pollution, occupational health, and fire. However, when water-based contact cement is used to bond foams as described above, the adhesive liquid penetrates into the pores of the foam and solidifies, causing the foam to lose its flexibility mainly near the adhesive layer. There was a serious drawback. The present invention relates to an adhesive composition for foams that does not have the above-mentioned drawbacks and a method for bonding foams using the adhesive composition. The composition of the present invention contains water-based contact cement 100%
2 to 10 foamed microspheres per part
It is made by mixing parts. This adhesive composition is applied to the bonding surfaces of the foams to be bonded together or to both the foam and other flexible materials, and the adhesive layer is heated to dry moisture and foam at the same time, and then If both are attached in contact with each other, strong adhesion can be achieved without losing flexibility near the adhesive layer. The aqueous contact cement used in the present invention refers to an aqueous latex of self-adhesive resin such as chloroprene rubber, acrylonitrile-butadiene rubber, styrene-butadiene rubber, and acrylic rubber, and the term "expandable microspheres" refers to, for example, Microcapsules of thermoplastic synthetic resin such as vinylidene chloride copolymer resin described in Patent No. 518820 contain low-boiling gaseous substances. When heated, the contained gaseous substances vaporize and expand, causing the resin to evaporate and expand. Refers to microcapsules that have the property of expanding significantly to increase their volume. In the present invention, the mixing ratio of aqueous contact cement and expandable microspheres is required to be 2 to 10 parts of microspheres to 100 parts of aqueous contact cement. If the mixing ratio of the microspheres is less than the above range, the foamability of the adhesive layer will be uneven and satisfactory flexibility will not be obtained. Furthermore, if the mixing ratio of the microspheres exceeds the above range, the contact properties of the adhesive will be lost and the adhesive strength will be significantly reduced. The present invention will be explained in more detail with reference to Examples below. "Middle part" in the example is based on weight. Example 1 Water-based contact cement (Panel Master 140
~8003, manufactured by Kanebo NSC) and 2 to 10 parts of expandable microspheres were mixed as shown in Table 1 to prepare an adhesive composition. The above adhesive composition was applied with a spray gun at a coating amount of 100 g/m ² to the surfaces to be bonded of a 3 mm thick urethane foam sheet and 70 μ soft PVC leather, and dried at 80°C for 2 minutes. , moisture in the adhesive layer evaporated and foaming occurred. Next, the 3 mm foamed urethane sheet and the PVC sheet were brought into position and pasted together, and the adhesive was completed by pressing with a hand roll. Flexibility and 80℃ for this adhesive
Peelability was measured. For comparison, one using only water-based contact cement, 1 part of microsphere for 100 parts of water-based contact cement,
A similar test was conducted using a mixture of 15 parts and 20 parts.

【table】

[Table] As can be seen from Table 1, when the amount of foamable microspheres added was too small, the foaming property became uneven, and the areas where foaming did not occur became hard due to the adhesive and the flexibility was impaired. Comparative Example 3 shows that when the amount of foamable microspheres becomes excessive, foaming occurs significantly and the adhesive itself loses its strength. Comparative Example 4 shows that when the amount of expandable microspheres is 10 parts or more per 100 parts of water-based contact cement, the adhesive property itself is lost and the adhesion to PVC leather becomes significantly lower. Example 2 Water-based contact cement (Panel Master 140
An adhesive composition was prepared by adding 3 parts of expandable microspheres to 100 parts of 8000 (manufactured by Kanebo NSC). The above adhesive composition was applied with a spray gun at a rate of 20 to 100 g/m ² as shown in Table 2 to the surfaces to be bonded of a 3 mm thick urethane foam sheet and a 10 mm thick urethane foam sheet, respectively, and heated at 100°C. The adhesive layer was dried for 2 minutes to remove moisture and foam the adhesive layer. Next, the 3 mm foamed urethane sheet and the 10mm foamed urethane sheet were pasted together, and the adhesive was completed by pressing firmly with a hand roll. The adhesive strength and flexibility of this adhesive were observed. For comparison, the same performance was shown when only water-based contact cement was used.

【table】

[Table] As can be seen from Table 2, in the example of the present invention, even with a small amount of application, sufficient adhesion can be obtained because the adhesive foams and protrudes from the pores of the foam, but with only aqueous contact cement. If a small amount is applied, the adhesive will flow into the pores of the foam and will not form a uniform adhesive layer, resulting in a decrease in adhesive strength. If the coating amount is increased, adhesion will be improved, but flexibility will be lost.

Claims (1)

[Claims] 1. Synthetic resin foams made by mixing 2 to 10 parts of unfoamed expandable microspheres to 100 parts of aqueous contact cement, or synthetic resin foams and other flexible adherends. Adhesive composition used for bonding. 2. When adhering synthetic resin foams to each other or synthetic resin foams to other flexible adherends, it is made by mixing 2 to 10 parts of unfoamed expandable microspheres to 100 parts of water-based contact cement. A method for adhering synthetic resin foams, which comprises applying an adhesive composition to both adhesive surfaces, heating the adhesive layer to dry water and foaming at the same time, and then contacting and adhering the two.