US3676527A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Process for preparation of high impact polystyrene
Assignee: Shell USA Inc
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Filing: 1970-10-26
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Granted: 1972-07-11
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Expires: 1990-10-26
Abstract
Abstract An improved process for the preparation of high impact polystyrene which comprises: (a) polymerizing monomers from the group consisting of styrene, or mixtures thereof with minor amounts of acrylonitrile and/or lower alkyl acrylates to a conversion between about 30 and about 55 percent by heating said monomers between about 90 and 120*C, (b) separately interpolymerizing a diene rubber with styrene at a rate between 5 and 17%w weight per hour to a conversion between 13 and 30 percent, and (c) admixing the two streams and (d) noncatalytically polymerizing substantially all of the polymerizable monomers in the resulting mixture to form the high-impact polystyrene composition.
Inventors
- 👤 Lyndon R Babcock Jr
- 👤 Dale A Walker
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 00:54
CPC Classifications
C; C08; C08F; C08F279/00; C08F279/02
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
34 words
A process according to claim 1 wherein 0.1-10 wt % of water is present at least in step (a), whereby heat of reaction of the polymerizable monomer is absorbed in evaporation of the water.
Claim 2
Dependent Claim
69 words
A process according to claim 1 wherein step (d) is conducted in two physically separated stages comprising: d1. continuing the polymerization of the mixture formed in step (c) up to 60-85 percent polymerization of starting monomers in a stirred reactor under reflux at temperatures within the range of 150*-180*C; d2. and thereafter passing the product so obtained to a separate unstirred reactor wherein polymerization is completed under adiabatic conditions.
Claim 3
Dependent Claim
12 words
A process according to claim 1 wherein the polymerizable monomer is styrene.
Claim 4
Dependent Claim
146 words
A process for producing high impact polystyrene which comprises: a. heating a solution of 8-14 wt % of an elastomeric polybutadiene in styrene at a temperature in the range between about 120* to about 130* C with mechanical mixing for a time sufficient to polymerize 15-30 wt % of the styrene at a rate of 10-15 wt % per hour; b. separately homopolymerizing styrene at a temperature of 90*-120*C for a time sufficient to polymerize 35-50 percent of the styrene; c. admixing the products of (a) and (b) in proportions such as to provide 4-8 wt % of polybutadiene; d1. continuing polymerization until 70-80% of the styrene has been polymerized under reflux in the presence of 1-5 wt % of water in a stirred reactor at temperatures of about 150*-180*C; d2. and thereafter substantially completely polymerizing remaining styrene under quiescent adiabatic conditions in a separate reactor.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1975-07-11 | 1976-01-10 | 1976-07-11 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-07-11 | 1980-01-10 | 1980-07-11 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-07-11 | 1984-01-10 | 1984-07-11 | $7700.00 | Window Closed / Lapsed |