US3923706A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Process for preparing self-extinguishing expandable polystyrene
Assignee: Atlantic Richfield Co
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Filing: 1974-11-18
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Granted: 1975-12-02
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Expires: 1994-11-18
Abstract
Abstract Polystyrene prepared in aqueous suspension is rendered selfextinguishing by adding pentabromochlorocyclohexane to the polymerizing monomer after about 92% conversion of monomer to polymer. The halo-compound is incorporated into the polystyrene by chain-transfer. Simultaneous addition of blowing agent produces a self-extinguishing, expandable polystyrene.
Inventors
- 👤 James J Uebelhart
- 👤 Jr John P Spicuzza
- 👤 Frank J E Mills
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 11:06
CPC Classifications
C; C08; C08J; C08J9/00; C08J9/16; C08J9/20; C08J2325/00; C08J2325/02; C08J2325/04; C08J2325/06; Y; Y10; Y10S; Y10S260/00; Y10S260/24
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
124 words
A PROCESS FOR PREPARING SELF-EXTRINGUISHING EXPANDABLE POLYSTYRENE PARTICLES COMPRISING THE STEPS OF: A. POLYMERIZING STYRENE IN AN AQUEOUS SUSPENSION IN THE PRESENCE OF A CATALYTIC AMOUNT OF A FREE RADICAL INITIATOR UNTIL THE POLYMERIZATION HAS PROGRESSED TO A POINT BE-TWEEN ABOUT 92 AND 98% CONVERSION OF MONOMER TO POLYMER; B. ADDING A MIXTURE CONSISTING OF FROM ABOUT 0.5 TO 5.0% BY WEIGHT BASED ON STYRENE OF PENTABROMOCHLOROCYCLOHEXANE, 5 TO 15% OF A BLOWING AGENT, AND 0.3 TO 0.5% OF FREE RADICAL INITIATOR; C. CHEMICALLY INCORPORATING THE PENTABROMOCLOROCYCLOHEXANE INTO THE GROWING POLYMER CHAINS BY COMPLETING THE POLYMERIZATION IN AQUEOUS SUSPENSION BY HEATING THE SUSPENSION UNDER CONDITIONS OF TEMPERATURE AND TIME SUFFICIENT TO COMPLETELTY POLYMERIZE THE REMAINING AND TIME MER; AD D. RECOVERING THE POLYMER PARTICLES.
Claim 2
Dependent Claim
124 words
A PROCESS FOR PREPARING SELF-EXTRINGUISHING EXPANDABLE POLYSTYRENE PARTICLES COMPRISING THE STEPS OF: A. POLYMERIZING STYRENE IN AN AQUEOUS SUSPENSION IN THE PRESENCE OF A CATALYTIC AMOUNT OF A FREE RADICAL INITIATOR UNTIL THE POLYMERIZATION HAS PROGRESSED TO A POINT BE-TWEEN ABOUT 92 AND 98% CONVERSION OF MONOMER TO POLYMER; B. ADDING A MIXTURE CONSISTING OF FROM ABOUT 0.5 TO 5.0% BY WEIGHT BASED ON STYRENE OF PENTABROMOCHLOROCYCLOHEXANE, 5 TO 15% OF A BLOWING AGENT, AND 0.3 TO 0.5% OF FREE RADICAL INITIATOR; C. CHEMICALLY INCORPORATING THE PENTABROMOCLOROCYCLOHEXANE INTO THE GROWING POLYMER CHAINS BY COMPLETING THE POLYMERIZATION IN AQUEOUS SUSPENSION BY HEATING THE SUSPENSION UNDER CONDITIONS OF TEMPERATURE AND TIME SUFFICIENT TO COMPLETELTY POLYMERIZE THE REMAINING AND TIME MER; AD D. RECOVERING THE POLYMER PARTICLES.
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) | 1978-12-01 | 1979-06-02 | 1979-12-02 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-12-01 | 1983-06-02 | 1983-12-02 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-12-01 | 1987-06-02 | 1987-12-02 | $7700.00 | Window Closed / Lapsed |