Method of producing ABS polyblends having a low residual monomer content
First Claim
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1. In an improved process for preparing an ABS polyblend having a low residual monomer content, the steps comprising:
- A. polymerizing a polymerizable mixture comprising a monomer formulation, a molecular weight regulator and a prepolymerized graftable rubber containing a diene monomer component, to graft at least a portion of the polymerizing monomers as superstrate interpolymer on said rubber as a rubber substrate to provide a graft copolymer, said monomer formulation consisting essentially of from about 60 to 85 percent by weight of styrene and from about 15 to 40 percent by weight of acrylonitrile, forming during polymerization thereof, an ABS polyblend of said graft copolymer and a matrix interpolymer, the improvement comprising;
B. charging a third monomer selected from the group consisting of vinyl acetate and methyl methacrylate and mixtures thereof to said polymerizable mixture in step (A) after polymerizing about 90 to 98% by weight of said monomer formulation, said third monomer being charged in an amount equivalent to about 2 to 10 percent by weight of the monomer formulation.C. further polymerizing said monomer formulation in the presence of said third monomer so as to convert essentially all of said monomer formulation to interpolymer, reducing said monomers of said monomer formulation to less than about 1.0% by weight as residual monomers in said interpolymer, andD. recovering said polyblend from said polymerizing mixture and drying said polyblend to remove essentially all residual monomers.
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Abstract
An improved process for preparing ABS polyblends, the steps comprising, polymerizing a polymerizable mixture of a monomer formulation and a diene rubber forming a grafted copolymer and a matrix interpolymer, the improvement comprising, polymerizing said monomer formulation to at least about 90% conversion, charging a third monomer and further polymerizing said monomer formulation in the presence of said third monomer to convert essentially all of said monomer formulation to interpolymer followed by recovering said polyblend having a low residual monomer content.
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Citations
21 Claims
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1. In an improved process for preparing an ABS polyblend having a low residual monomer content, the steps comprising:
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A. polymerizing a polymerizable mixture comprising a monomer formulation, a molecular weight regulator and a prepolymerized graftable rubber containing a diene monomer component, to graft at least a portion of the polymerizing monomers as superstrate interpolymer on said rubber as a rubber substrate to provide a graft copolymer, said monomer formulation consisting essentially of from about 60 to 85 percent by weight of styrene and from about 15 to 40 percent by weight of acrylonitrile, forming during polymerization thereof, an ABS polyblend of said graft copolymer and a matrix interpolymer, the improvement comprising; B. charging a third monomer selected from the group consisting of vinyl acetate and methyl methacrylate and mixtures thereof to said polymerizable mixture in step (A) after polymerizing about 90 to 98% by weight of said monomer formulation, said third monomer being charged in an amount equivalent to about 2 to 10 percent by weight of the monomer formulation. C. further polymerizing said monomer formulation in the presence of said third monomer so as to convert essentially all of said monomer formulation to interpolymer, reducing said monomers of said monomer formulation to less than about 1.0% by weight as residual monomers in said interpolymer, and D. recovering said polyblend from said polymerizing mixture and drying said polyblend to remove essentially all residual monomers. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21)
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Specification