Abstract A graft copolymer is prepared by polymerizing monomeric styrene and acrylonitrile in a latex of a synthetic rubbery copolymer of about 90 parts of butadiene and 10 parts of styrene having at least 80 percent gel content. The average particle diameter of the latex is 2,000 to 5,000 angstrom units. From 40 to 55 parts of the monomers are used with correspondingly from 60 to 45 parts of the synthetic rubber. The polymerization is carried at 120*175* F. to a conversion of at least 85 percent of the styrene and acrylonitrile to copolymer. The anionic surface-active emulsifier level during the grafting is maintained at not over 5 parts per 100 parts of rubber and styrene-acrylonitrile copolymer that has been polymerized in the latex until at least 75 percent of the styrene and acrylonitrile monomer mixture to be polymerized in admixture with the synthetic rubber has been converted to polymer. Preferably the rubber latex is prepared by at 100*-170* F. in the presence of 0.1-0.3 part of alkalimetal soap per 100 parts of butadiene and sytrene until 20-50 percent conversion, 1.5-2.3 parts of such soap being added during further conversion. The resulting graft copolymer can be blended, preferably by latex blending, with a separately prepared copolymer resin of 6080 parts of styrene and/or alpha-methyl styrene and correspondingly 40-20 parts of acrylonitrile. Articles formed from the disclosed graft copolymer compositions are characterized by high surface gloss.
The process for making a graft copolymer as claimed in claim 1 in which the styrene and acrylonitrile mixture is added continuously to the synthetic rubber latex.
Claim 2
Dependent Claim
29 words
The process for making a graft copolymer as claimed in claim 2 in which the average particle diameter of the synthetic rubber latex is 2,500 to 3,500 angstrom units.
Claim 3
Dependent Claim
91 words
The process for making graft copolymer as claimed in claim 1 in which the synthetic rubber latex is prepared by polymerizing about 90 parts of buTadiene and about 10 parts of styrene in 50 to 100 parts of water at 110* to 170* F. initially in the presence of 0.1 to 0.3 part of alkali metal soap of soap-forming monocarboxylic acid until 20 to 50 percent conversion, and thereafter adding 1.5 to 2.3 parts of such alkali metal soap during further conversion to a final conversion of at least 90 percent.
Claim 4
Dependent Claim
80 words
The process which comprises intimately mixing the graft copolymer made by the process of claim 1 with a separately prepared copolymer resin of 60 to 80 parts of material selected from the group consisting of styrene and alpha-methylstyrene and correspondingly 40 to 20 parts of acrylonitrile, the ratio of graft copolymer to said separately prepared copolymer resin being from 90 to 10 parts of the graft copolymer to a corresponding 10 to 90 parts of the separately prepared copolymer resin.
Claim 5
Dependent Claim
80 words
The process which comprises intimately mixing the graft copolymer made by the process of claim 1 with a separately prepared copolymer resin of 60 to 80 parts of material selected from the group consisting of styrene and alpha-methylstyrene and correspondingly 40 to 20 parts of acrylonitrile, the ratio of graft copolymer to said separately prepared copolymer resin being from 90 to 10 parts of the graft copolymer to a corresponding 10 to 90 parts of the separately prepared copolymer resin.
Claim 6
Dependent Claim
41 words
The process of claim 6 in which the mixture of graft copolymer and separately prepared copolymer resin is made by blending the latex of the graft copolymer with the latex of the separately prepared copolymer resin, coagulating and drying the coagulum.