Ethylene-vinyl acetate copolymer adhesive composition and method of preparation

Claim 2

The process defined in claim 1 wherein said fully hydrolyzed polyvinyl acetate exhibits a viscosity of from about 5 to 125 centipoises for a 4 weight percent aqueous solution at a temperature of 20* C.

Claim 3

The process defined in claim 1 wherein said weight ratio of fully to partially hydrolyzed polyvinyl alcohol is between about 1 to 5 and 5 to 1.

Claim 4

The process defined in claim 1 wherein about 0.01 and 5 weight percent of an emulsifying agent is also emulsified in said aqueous medium.

Claim 5

The process defined in claim 1 wherein about 0.01 and 10 weight percent of plasticizer is emulsified with said adhesive emulsion.

Claim 6

The product made by the process of claim 1.

Claim 7

A process for the production of an emulsion adhesive which comprises: emulsifying in an aqueous medium having a pH of about 3 to 9 the following ingredients: (1) between about 5 to 50 weight percent of an aqueous seed emulsion comprising from 1 to 5 weight percent of partially hydrolyzed polyvinyl acetate having from 50 to 95 percent of its acetate groups hydrolyzed and from 25 to 65 weight percent of ethylene-vinyl acetate copolymers having about 1 to 20 weight percent ethylene, (2) between about 0.01 and 1 weight percent of a polyvinyl alcohol mixture comprising fully hydrolyzed polyvinyl acetate and partially hydrolyzed polyvinyl acetate having from 50 to 95 percent of its acetate groups hydrolyzed with a weight ratio of fully to partially hydrolyzed polyvinyl acetate between about 1 to 10 and 10 to 1, and (3) between about 0.1 and 5 weight peRcent of vinyl acetate monomer; contacting the emulsified mixture with a water-soluble free radical polymerization initiator and ethylene at a pressure of from 100 to 1,000 psig. and maintaining the temperature of said emulsified mixture between about 100* and 200* F. to activate said initiator and copolymerize said ethylene and vinyl acetate; slowly introducing into said emulsified mixture during said copolymerization an additional amount of vinyl acetate and said polyvinyl alcohol mixture so that the total amount of vinyl acetate added to the emulsified mixture is from about 5 to 60 weight percent and the total amount of polyvinyl alcohol mixture added to the emulsified mixture is from 1.5 to 6 weight percent; and maintaining copolymerization conditions until the free vinyl acetate monomer content of said emulsion is reduced to less than 1 weight percent.

Claim 8

The process defined in claim 8 wherein said partially hydrolyzed polyvinyl acetate in said seed emulsion and in said polyvinyl alcohol mixture is from about 80 to 95 percent hydrolyzed and exhibits a viscosity of about 2 to 80 centipoises for a 4 weight percent aqueous solution at a temperature of 20* C.

Claim 9

The process defined in claim 8 wherein said fully hydrolyzed polyvinyl acetate exhibits a viscosity of from about 5 to 125 centipoises for a 4 weight percent aqueous solution at a temperature of 20* C.

Claim 10

The process defined in claim 8 wherein said weight ratio of fully hydrolyzed to partially hydrolyzed polyvinyl acetate is between about 1 to 5 and 5 to 1.

Claim 11

The process defined in claim 8 wherein about 0.01 and 5 weight percent of an emulsifying agent is also emulsified in said aqueous medium.

Claim 12

The process defined in claim 8 wherein a redox agent is also emulsified in said aqueous medium.

Claim 13

An article of manufacture comprising a substrate having a solid surface, a vinyl plastic having a surface conjunctive with the solid surface of said substrate and adhered thereto by an adhesive interlayer formed from an ethylene-vinyl acetate adhesive emulsion prepared by the method of claim 1.

Claim 14

The article of claim 14 wherein said substrate is wood, glass, metal, concrete or a synthetic resin.

Claim 15

The article of claim 15 wherein said resin is polyvinyl chloride.