Patent US2973241A successfully refreshed from Google Patents.
US3663675A
Expired / Lapsed
US
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Process for producing crimped polypropylene filaments
Assignee: Asahi Kasei Corp
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Filing: 1970-07-24
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Granted: 1972-05-16
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Expires: 1990-07-24
Abstract
Abstract CRYSTALLINE POLYPROPYLENE HAVING AN INTRISIC VISCOSITY OF 1.2 TO 2.2 WHICH IS OBTAINED BY DEPOLYMERIZING POLYPROPYLENE HAVING AN INTRINSIC VISOCITY OF 1.2 TO 4.2 BY A DEPOLYMERIZATION DEGREE OF AT MOST 1.9 AND AT MOST 20% BY WEIGHT OF ADDITIVES IS MELT-SPUN THROUGH A SPINNERET AT A TEMPERATURE OF 260 TO 280*C. AND AT A SPINNING SPEED OF MORE THAN 600 M./MIN. TO FORM UNDRAWN FILIMENTS. THE RESULTANT UNDRAWN FILAMENTS HAVING AN INTRINSIC VISOCITY OF 0.8-1.4 ARE HEAT TREATED AT A TEMPERATURE OF 120-150*C., DRAWN AT A TEMPERATURE OF 110-150*C., AND THEREAFTER RELAXED TO PODUCE FINELY CRIMPED FILAMENTS HAVING A LARGE NUMBER OF CRIMPS AND GOOD CRIMP RETENTION ABILITY.
Inventors
- 👤 Noboru Fukuma
- 👤 Kenichi Matsui
- 👤 Hiroshi Shimizu
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 16:42
CPC Classifications
D; D01; D01F; D01F6/00; D01F6/02; D01F6/04; D01F6/06
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1975-05-16 | 1975-11-15 | 1976-05-16 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-05-16 | 1979-11-15 | 1980-05-16 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-05-16 | 1983-11-15 | 1984-05-16 | $7700.00 | Window Closed / Lapsed |