Sumitomo Chemical Company, Limited

Choji Tomizawa

Takeo Oyamada

Yutaka Shibata

Shizuo Narisawa

Masahiro Domoto

Yoshito Taira

Shinobu Tsuru

Takamasa Ishihara

Kazuhisa Satoh

Hiromichi Tanaka

An adhesive composition obtainable by blending a component (C) to components (A) and (B), wherein the weight ratio of (A)/(B) is from 95/5 to 40/60, and the amount of the component (C) is from 5 to 50 parts by weight based on 100 parts by weight of the total amount of the components (A) and (B):

Adhesive composition

A jointing of concrete structure comprising applying an adhesive to a base concrete structure and applying a new concrete thereto, which is characteristic in that the adhesive comprises a vinyl acetate-ethylene copolymer emulsion having a glass transition temperature of -5.degree. to +5.degree. C., said adhesive being the vinyl acetate-ethylene copolymer emulsion per se, or a cement paste or cement mortar which contains the vinyl acetate-ethylene copolymer emulsion. The jointing of the present invention can give a strong joint force between the old concrete structure and the new concrete.

Jointing of concrete structure

A pressure-sensitive adhesive containing a base material therefore comprising an aqueous emulsion of vinyl acetate-ethylene copolymer having an ethylene content of 15 to 40% by weight, preferably 20 to 35% by weight, the benzene-insoluble part of less than 30% by weight, preferably less than 20% by weight, and an intrinsic viscosity of the benzene-soluble part of 0.4 to 1.4 dl/g, preferably 0.6 to 1.0 dl/g, (at 30.degree. C) which is prepared by the emulsion copolymerization of vinyl acetate and ethylene and optionally at least one unsaturated monovinyl monomer in the presence of a protective colloid and a polyoxyethylenic nonionic sulfactant, or a base material comprising a blend of said aqueous emulsion of vinyl acetate-ethylene copolymer as set forth above and an emulsion of an acrylic ester copolymer; and the aqueous emulsion of vinyl acetate-ethylene copolymer useful as the base material for the pressure-sensitive adhesive.

Pressure-sensitive adhesive and vinyl acetate-ethylene copolymer

In the process for producing the aqueous emulsion of vinyl chloride/vinyl acetate/ethylene terpolymer by polymerizing vinyl chloride, vinyl acetate and ethylene in an aqueous dispersion system under ethylene pressure in the presence of an emulsifier and/or protective colloid using a radical initiator, the improvement which comprises adding vinyl chloride and vinyl acetate to said aqueous dispersion system at substantially fixed rates while maintaining a required amount of unreacted vinyl acetate in the system, and, after completion of addition of vinyl chloride, adding additional vinyl acetate of 3 to 20% by weight based on the total amount of vinyl acetate which has been added until that time and continuing the polymerization until the concentration of vinyl acetate in the system is decreased to 1% by weight or less, wherein the volume of the aqueous dispersion system is at least 50% by volume based on the volume of the reactor when addition of the additional vinyl acetate is completed. By this process, the amount of unreacted vinyl chloride in said aqueous emulsion can be decreased to a large extent.

Process for producing aqueous emulsions of vinyl chloride/vinyl

A process for producing an aqueous dispersion of vinyl acetate-ethylene copolymer containing an epoxide resin, which comprises emulsion-copolymerizing vinyl acetate, wherein an epoxide resin is dissolved, and ethylene at a pH value of 3 to 7 so that the ratio of vinyl acetate to ethylene is 60-95 : 40-5 by weight and the content of the epoxide resin is 0.5 to 60% by weight on the basis of the total weight of the solid resin components. The aqueous dispersion is useful as a two-pack type adhesive or coating composition in combination with a curing agent.

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Ichihara, Japan

Choji Tomizawa