Patent US4255295A successfully refreshed from Google Patents.
US4255295A
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Process for the regeneration of polymer from waste
Assignee: Rhone Poulenc Textile SA
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Filing: 1979-10-01
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Granted: 1981-03-10
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Expires: 1999-10-01
Abstract
Abstract A process is disclosed for the production of a polymer of good spinnability from waste. It consists in compressing the finely chopped waste by means of a screw until a bulk density of at least 500 kg/m 3 is reached, introducing same into a double screw degassing extruder, and subjecting the molten polymer to a post-condensation operation. The polymer obtained can be used as such in many textile applications and in plastics.
Inventors
- 👤 Bernard Regnault
- 👤 Pierre Revol
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 15:39
CPC Classifications
B; B29; B29B; B29B17/00; B29B17/0026; C; C08; C08J; C08J11/00; C08J11/04; C08J11/06; B29K; B29K2067/00; B29K2067/006; C08J2367/00; C08J2367/02; Y; Y02; Y02W; Y02W30/00; Y02W30/50; Y02W30/62
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
115 words
A process for the production of a poly-(polymethylene terephthalate) polymer of good spinnability from waste of low bulk density containing poly-(polymethylene) terephthalate, characterized in that the said waste is finely chopped, compressed by means of a screw until a bulk density of at least 500 kg/m 3 is reached, then introduced in this form into a double screw degassing extruder in which it is melted whilst the traces of water and of volatile impurities are removed, and the molten polymer then is subjected to a post-condensation operation under reduced pressure thereby raising its intrinsic viscosity to the desired value and decomposing the non-volatile impurities to give volatile products which are removed under the reduced pressure.
Claim 2
Dependent Claim
115 words
A process for the production of a poly-(polymethylene terephthalate) polymer of good spinnability from waste of low bulk density containing poly-(polymethylene) terephthalate, characterized in that the said waste is finely chopped, compressed by means of a screw until a bulk density of at least 500 kg/m 3 is reached, then introduced in this form into a double screw degassing extruder in which it is melted whilst the traces of water and of volatile impurities are removed, and the molten polymer then is subjected to a post-condensation operation under reduced pressure thereby raising its intrinsic viscosity to the desired value and decomposing the non-volatile impurities to give volatile products which are removed under the reduced pressure.
Claim 3
Dependent Claim
29 words
A process according to claim 1, characterized in that the molten polymer is subjected to at least one filtration between its discharge from the extruder and the post-condensation operation.
Claim 4
Dependent Claim
35 words
A process according to claim 1 or 2 characterized in that the extruder comprises a feed and degassing zone, a melting zone, a kneading zone, and a zone for degassing and compressing the polymeric material.
Claim 5
Dependent Claim
24 words
A process according to claim 3, characterized in that the various zones of the extruder are maintained at a temperature of about 300° C.
Claim 6
Dependent Claim
17 words
A process according to claim 1, wherein the said bulk density is about 600 kg/m 3 .
References Cited (Backward Citations)
US4143001A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1984-03-09 | 1984-09-08 | 1985-03-10 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1988-03-09 | 1988-09-08 | 1989-03-10 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1992-03-09 | 1992-09-08 | 1993-03-10 | $7700.00 | Window Closed / Lapsed |