Claims
- 1. A process for preparing copolymers of .alpha.-methyl styrene and acrylonitrile having improved uniformity and an overall monomer weight ratio (.alpha.-methyl styrene/acrylonitrile) from about 70/30 to about 85/15 comprising the steps of:
- (1) charging a first monomer feed stream comprising .alpha.-methyl styrene and acrylonitrile in a weight ratio of from about 75/25 to about 85/15 in a continuous or semicontinuous manner to a well mixed reactor operating under emulsion polymerization conditions and initially comprising from about 0.05 to about 5.0 percent by weight (based on final copolymer weight) of a polymeric seed latex, until the weight percent of unreacted .alpha.-methyl styrene plus acrylonitrile based on total monomer and polymer weight is about 20-45;
- (2) continuously or semicontinuously charging to the reactor with mixing under emulsion polymerization conditions a second monomer feed stream comprising acrylonitrile in the substantial absence of .alpha.-methyl styrene until the weight percent of unreacted .alpha.-methyl styrene plus acrylonitrile remaining in the reactor is about 5-15 percent based on total monomer weight;
- (3) continuing the emulsion polymerization until total monomer conversion reaches at least about 90 percent;
- (4) recovering the copolymer of .alpha.-methyl styrene and acrylonitrile.
- 2. The process of claim 1 wherein the first monomer feed stream consists essentially of .alpha.-methyl styrene and acrylonitrile.
- 3. A process for preparing copolymers of .alpha.-methylstyrene and acrylonitrile having improved uniformity and an overall monomer weight ratio (.alpha.-methylstyrene/acrylonitrile) from about 70/30 to about 85/15 comprising the steps of:
- (1) charging a first monomer feed stream comprising .alpha.-methylstyrene and acrylonitrile in a weight ratio of from about 75/25 to about 85/15 in a continuous or semicontinuous manner to a well mixed reactor operating under emulsion polymerization conditions and initially comprising from about 0.05 to about 5.0% by weight (based on final copolymer weight) of a polymeric seed latex, until the weight percent of unreacted .alpha.-methylstyrene plus acrylonitrile based on total monomer and polymer weight is about 20-45 and the excess of unreacted .alpha.-methylstyrene monomer is from 600 to about 5000 weight percent based on unreacted acrylonitrile;
- (2) continuously or semicontinuously charging to the reactor with mixing under emulsion polymerization conditions a second monomer feed stream comprising acrylonitrile in the substantial absence of .alpha.-methylstyrene until the weight percent of unreacted .alpha.-methylstyrene plus acrylonitrile remaining in the reactor is about 5-15% based on total monomer weight while maintaining an excess of unreacted .alpha.-methylstyrene of from 600 to 5000 weight percent based on the weight of unreacted acrylonitrile;
- (3) continuing the emulsion polymerization until total monomer conversion reaches at least about 90%;
- (4) recovering the copolymer of .alpha.-methylstyrene and acrylonitrile.
- 4. The process of claim 3 wherein the first monomer feed stream consists essentially of .alpha.-methyl styrene and acrylonitrile.
- 5. A process according to claim 3 wherein the first monomer stream has a monomer ratio of .alpha.-methylstyrene/acrylonitrile from about 80/20 to about 85/15.
- 6. A process according to claim 3 wherein the total monomer conversion reaches from about 90% to about 96%.
Parent Case Info
This is a continuation, of application Ser. No. 134,415 filed Dec. 17, 1987, now abandoned.
US Referenced Citations (11)
Continuations (1)
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Number |
Date |
Country |
Parent |
134415 |
Dec 1987 |
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