US4472241A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Co-refining of aramid fibrids and floc
Assignee: EIDP Inc
•
Filing: 1983-06-15
•
Granted: 1984-09-18
•
Expires: 2003-06-15
Abstract
Abstract An aqueous slurry of 0.2 to 2.0 weight percent aramid fibrids and aramid floc in a weight ratio of 0.25 to 20, respectively, is refined in a disc refiner having grooved facing plates with surface dams, the distance between the facing plates being 0.20 to 1.0 mm.
Inventors
- 👤 Richard L. Provost
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 02:31
CPC Classifications
D; D21; D21D; D21D1/00; D21D1/20; D21D1/30; D21H; D21H13/00; D21H13/10; D21H13/20; D21H13/26
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
129 words
Process for refining an aqueous slurry of aramid fibrids and aramid floc wherein an aqueous slurry comprised of 0.2 to 2.0 percent by weight of aramid fibrids and 2 to 12 mm long aramid floc in a weight ratio of 0.25 to 20, respectively, is processed in a disc refiner fitted with facing circular plates rotable with respect to one another having multiple radially extruding grooves, the grooves being at an angle of 0° to 45° to the plate radius and being 1.6 to 6.4 mm wide, 1.6 to 6.4 mm deep and 1.6 to 6.4 mm apart, each groove having a least one dam extending at least half the distance to the plate surface, the clearance between the surfaces of the facing plates being 0.20 to 1.0 mm.
Claim 2
Dependent Claim
129 words
Process for refining an aqueous slurry of aramid fibrids and aramid floc wherein an aqueous slurry comprised of 0.2 to 2.0 percent by weight of aramid fibrids and 2 to 12 mm long aramid floc in a weight ratio of 0.25 to 20, respectively, is processed in a disc refiner fitted with facing circular plates rotable with respect to one another having multiple radially extruding grooves, the grooves being at an angle of 0° to 45° to the plate radius and being 1.6 to 6.4 mm wide, 1.6 to 6.4 mm deep and 1.6 to 6.4 mm apart, each groove having a least one dam extending at least half the distance to the plate surface, the clearance between the surfaces of the facing plates being 0.20 to 1.0 mm.
Claim 3
Dependent Claim
13 words
Process of claim 1 wherein the floc is 2 to 6 mm long.
Claim 4
Dependent Claim
16 words
Process of claim 1 wherein the weight ratio of fibrids to floc is 0.6 to 1.5.
Claim 5
Dependent Claim
14 words
Process of claim 3 wherein the weight ratio of fibrids to floc is 1.0.
Claim 6
Dependent Claim
12 words
Process of claim 1 wherein the clearance is 0.4 to 0.5 mm.
Claim 7
Dependent Claim
11 words
Process of claim 1 wherein a double disc refiner is used.
Claim 8
Dependent Claim
15 words
Process of claim 6 wherein the slurry is passed through the refiner more than once.
References Cited (Backward Citations)
US2999788A
Cited
US3240437A
Cited
US3745645A
Cited
US3756908A
Cited
US4039154A
Cited
US4237081A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1987-09-18 | 1988-03-19 | 1988-09-18 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1991-09-18 | 1992-03-19 | 1992-09-18 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1995-09-18 | 1996-03-19 | 1996-09-18 | $7700.00 | Window Closed / Lapsed |