US4598101A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Polymer foam, thermoformed shapes thereof and methods of forming same
Assignee: Pactiv LLC
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Filing: 1985-07-29
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Granted: 1986-07-01
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Expires: 2005-07-29
Abstract
Abstract A polyphenylene oxide/polystyrene polymer blend foam structure having a density of less than about 20 lbs/ft3. The method of forming said foam comprising combining the polymer blend with a blowing agent member selected from the group consisting of methylene chloride, chloroform, 1,1,2-trichloroethane and mixtures thereof in molten form under pressure and extruding the same into a lower pressure region to form the foam.
Inventors
- 👤 Charles M. Krutchen
- 👤 Wen-Pao Wu
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 23:12
CPC Classifications
C; C08; C08J; C08J9/00; C08J9/04; C08J9/12; C08J9/14; C08J9/143; C08J9/144; C08J9/145; B; B29; B29C; B29C44/00; B29C44/34; B29C44/36; B29C44/46; B29C44/50; B29C44/507; B29C51/00; B29C51/002; B29K; B29K2079/00; C08J2379/00; C08J2379/04; C08J2379/08; Y; Y10; Y10S; Y10S264/00; Y10S264/05
Claims Analysis
Total Claims: 3
Claim 1
Independent Claim
110 words
The process of preparing a low density resin blend foam structure comprising: (a) providing a blend of polyphenylene oxide and a high impact polystyrene in an extrusion system under pressure and melting the same; (b) homogeneously mixing the molten polymer blend with a blowing agent member selected from the group consisting of methylene chloride, chloroform, 1,1,2-trichloroethane and mixtures thereof, said blowing agent being present in a proportion sufficient to foam the polymer blend to a density less than about 20 lbs./ft 3 ; and (c) extruding the melt blend into a lower pressure atmosphere to cause the blowing agent to vaporize yielding a polyphenylene oxide/high impact polystyrene blend foam structure.
Claim 2
Dependent Claim
110 words
The process of preparing a low density resin blend foam structure comprising: (a) providing a blend of polyphenylene oxide and a high impact polystyrene in an extrusion system under pressure and melting the same; (b) homogeneously mixing the molten polymer blend with a blowing agent member selected from the group consisting of methylene chloride, chloroform, 1,1,2-trichloroethane and mixtures thereof, said blowing agent being present in a proportion sufficient to foam the polymer blend to a density less than about 20 lbs./ft 3 ; and (c) extruding the melt blend into a lower pressure atmosphere to cause the blowing agent to vaporize yielding a polyphenylene oxide/high impact polystyrene blend foam structure.
Claim 3
Dependent Claim
36 words
The method of claim 1 wherein the polyphenylene oxide is present in the blend in from about 20-80 weight percent and the high impact polystyrene is present in the blend in from about 20-80 weight percent.
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) | 1989-06-30 | 1989-12-30 | 1990-07-01 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1993-06-30 | 1993-12-30 | 1994-07-01 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1997-06-30 | 1997-12-30 | 1998-07-01 | $7700.00 | Window Closed / Lapsed |