US3690569A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Granular polytetrafluoroethylene of good moldability and apparent bulk density
Assignee: EIDP Inc
•
Filing: 1970-09-24
•
Granted: 1972-09-12
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Expires: 1990-09-24
Abstract
Abstract Granular polytetrafluoroethylene is ground to a particle size of about 20-50 microns, and slurried in water at a temperature less than 40* C. to increase the apparent bulk density of the polymer without a substantial change to the moldability index and particle size thereof.
Inventors
- 👤 Glenn Frederick Leverett
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 07:55
CPC Classifications
C; C08; C08J; C08J3/00; C08J3/12; C08J2327/00; C08J2327/02; C08J2327/12; C08J2327/18; Y; Y10; Y10S; Y10S526/00; Y10S526/909
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
13 words
The process of claim 1 wherein the temperature is no greater than 3*C.
Claim 2
Dependent Claim
15 words
The process of claim 1 wherein the particle size is from 10 to 75 microns.
Claim 3
Dependent Claim
22 words
The process of claim 1 followed by at least one additional cycle of comminution and agitation as set forth in claim 1.
Claim 4
Dependent Claim
21 words
The process of claim 1 wherein the comminution is carried out at a temperature in the range of 0* to 40*C.
Claim 5
Dependent Claim
18 words
The process of claim 5 wherein the comminution is carried out at a temperature of less than 15*C.
Claim 6
Dependent Claim
26 words
The process of claim 1 wherein the agitation is sufficient to increase the apparent bulk density of said polytetrafluoroethylene to be in excess of 450 g/l.
Claim 7
Dependent Claim
30 words
The process of claim 1 wherein the agitation is conducted so that neither the moldability index nor particle size 23 so of the polytetrafluoroethylene increases by more than 20 percent.
Claim 8
Dependent Claim
19 words
The process of claim 1 wherein before comminution the polytetrafluoroethylene has a particle size of at least 500 microns.
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) | 1975-09-12 | 1976-03-13 | 1976-09-12 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-09-12 | 1980-03-13 | 1980-09-12 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-09-12 | 1984-03-13 | 1984-09-12 | $7700.00 | Window Closed / Lapsed |