US3245972A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Polytetrafluoroethylene molding powder and its preparation
Assignee: EIDP Inc
•
Filing: 1962-06-21
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Granted: 1966-04-12
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Expires: 1982-06-21
Abstract
No abstract record available.
Inventors
- 👤 Anderson Roland Fitzhugh
- 👤 Edens William Lee
- 👤 Larsen Howland Aikens
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 09:32
CPC Classifications
C; C08; C08F; C08F14/00; C08F14/18; C08F14/26; Y; Y10; Y10T; Y10T428/00; Y10T428/29; Y10T428/2982
Claims Analysis
Total Claims: 3
Claim 1
Independent Claim
138 words
A PROCESS FOR PREPARING POLYTETRAFLUOROETHYLENE MOLDING POWDER WHICH COMPRISES POLYMERIZING TETRAFLUOROETHYLENE IN CONTACT WITH A STIRRED AQUEOUS MEDIUM CONTAINING A FREE RADICAL INITIATOR AND SOLID NUCLEI IN THE FORM OF AGGLOMERATED NON-WATER-WET PARTICLES HAVING A TOTAL SURFACE AREA PER GRAM OF GREATER THAN 3 SQUARE METERS CHARACTERIZED IN THEAT THE POWER APPLIED TO SAID MEDIUM IN STIRRING IS IN THE RANGE OF 0.0004 TO 0.002 KG.-M./SEC./ML., SAID MEDIUM CONTAINS AT LEAST 5 X 10**10 NUCLEI PER MILLITER, POLYMERIZATION IS CONTAINED AT A TEMPERATURE IN THE RANGE OF 60*C. TO 130*C, AND A PRESSURE IN THE RANGE OF 10 TO 50 ATMOSPHERES, UNTIL THE PARTICLES HAVE A REDUCED TOTAL SURFACE AREA PER GRAM OF LESS THAN 9 SQUARE METERS, AND POLYMERI ZATION IN DISCONTINUED BEFORE THE TOTAL SURFACE AREA OF THE PARTICLES PER GRAM FALLS BELOW 3 SQUARE METERS.
Claim 2
Dependent Claim
138 words
A PROCESS FOR PREPARING POLYTETRAFLUOROETHYLENE MOLDING POWDER WHICH COMPRISES POLYMERIZING TETRAFLUOROETHYLENE IN CONTACT WITH A STIRRED AQUEOUS MEDIUM CONTAINING A FREE RADICAL INITIATOR AND SOLID NUCLEI IN THE FORM OF AGGLOMERATED NON-WATER-WET PARTICLES HAVING A TOTAL SURFACE AREA PER GRAM OF GREATER THAN 3 SQUARE METERS CHARACTERIZED IN THEAT THE POWER APPLIED TO SAID MEDIUM IN STIRRING IS IN THE RANGE OF 0.0004 TO 0.002 KG.-M./SEC./ML., SAID MEDIUM CONTAINS AT LEAST 5 X 10**10 NUCLEI PER MILLITER, POLYMERIZATION IS CONTAINED AT A TEMPERATURE IN THE RANGE OF 60*C. TO 130*C, AND A PRESSURE IN THE RANGE OF 10 TO 50 ATMOSPHERES, UNTIL THE PARTICLES HAVE A REDUCED TOTAL SURFACE AREA PER GRAM OF LESS THAN 9 SQUARE METERS, AND POLYMERI ZATION IN DISCONTINUED BEFORE THE TOTAL SURFACE AREA OF THE PARTICLES PER GRAM FALLS BELOW 3 SQUARE METERS.
Claim 3
Dependent Claim
52 words
POLYTETRAFLUOROETHYLENE MOLDING POWDER MADE BY THE PROCESS OF CLAIM 1 HAVING A TOTAL SURFACE AREA PER GRAM OF AT LEAST 3 AND LESS THAN 9 SQUARE METERS PER GRAM, A STANDARD SPECIFIC GRAVITY OF LESS THAN 2.2, A MOLDABILITY INDEX OF LESS THAN 50, AND AN APPARENT DENSITY OF AT LEAST 400G./LITER.
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) | 1969-04-11 | 1969-10-11 | 1970-04-12 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1973-04-11 | 1973-10-11 | 1974-04-12 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1977-04-11 | 1977-10-11 | 1978-04-12 | $7700.00 | Window Closed / Lapsed |