Patent US3256372A successfully refreshed from Google Patents.
US3256372A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method for preparing modified cellulose filter material
Assignee: Primerica Inc
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Filing: 1964-04-28
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Granted: 1966-06-14
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Expires: 1984-04-28
Abstract
No abstract record available.
Inventors
- 👤 James W Adams
- 👤 Henry W Hoftiezer
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 12:28
CPC Classifications
B; B01; B01D; B01D39/00; B01D39/02; B01D39/04; Y; Y10; Y10S; Y10S55/00; Y10S55/05
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
151 words
A METHOD OF FORMING A POROUS MATERIAL BASED ON FIBROUS CELLULOSE WHICH COMPRISES (A) CHEMICALLY BONDING TO FIBERS OF NATURAL CELLULOSE A POLYMER FORMED THEREIN AND THEREON BY IN SITU POLYMERIZATION, SAID POLYMER BEING SELECTED FROM THE GROUP CONSISTING OF POLYACRYLAMIDE, POLYMETHYACRYLAMIDE, ALKALI SALTS OF POLYACRYLIC ACID, ALKALI SALTS OF POLYMETHYLACRYLIC ACID, AND COPOLYMERS THEREOF, (B) FORMING AN AQUEOUS SLURRY OF FIBERS OF NATURAL CELLULOSE FIBERS INCLUDING SAID FIBERS HAVING POLYMER CHEMICALLY BONDED THEREIN AND THEREON, SAID POLYMER BONDED FIBERS BEING PRESENT IN SAID SLURRY IN SUCH AMOUNT THAT SIA D POLYMER CONSTITUTES BETWEEN ABOUT 20 PERCENT AND 90 PERCENT OF THE SOLIDS WEIGHT IN SAID SLURRY, (C) MOLDING AN OBJECT OF DESIRED CONFIGURATION FROM SAID SLURRY AND (D) DRYING THE MOLDED OBJECT WHILE EFFECTIVELY MAINTAINING THE INDIVIDUAL FIBERS IN A DEGREE OF SEPARATION FROM ONE ANOTHER NOT SUBSTANTIALLY LESS THAN THAT ASSUMED BY SAID FIBERS IN THE WET MOLDED OBJECT.
Claim 2
Independent Claim
151 words
A METHOD OF FORMING A POROUS MATERIAL BASED ON FIBROUS CELLULOSE WHICH COMPRISES (A) CHEMICALLY BONDING TO FIBERS OF NATURAL CELLULOSE A POLYMER FORMED THEREIN AND THEREON BY IN SITU POLYMERIZATION, SAID POLYMER BEING SELECTED FROM THE GROUP CONSISTING OF POLYACRYLAMIDE, POLYMETHYACRYLAMIDE, ALKALI SALTS OF POLYACRYLIC ACID, ALKALI SALTS OF POLYMETHYLACRYLIC ACID, AND COPOLYMERS THEREOF, (B) FORMING AN AQUEOUS SLURRY OF FIBERS OF NATURAL CELLULOSE FIBERS INCLUDING SAID FIBERS HAVING POLYMER CHEMICALLY BONDED THEREIN AND THEREON, SAID POLYMER BONDED FIBERS BEING PRESENT IN SAID SLURRY IN SUCH AMOUNT THAT SIA D POLYMER CONSTITUTES BETWEEN ABOUT 20 PERCENT AND 90 PERCENT OF THE SOLIDS WEIGHT IN SAID SLURRY, (C) MOLDING AN OBJECT OF DESIRED CONFIGURATION FROM SAID SLURRY AND (D) DRYING THE MOLDED OBJECT WHILE EFFECTIVELY MAINTAINING THE INDIVIDUAL FIBERS IN A DEGREE OF SEPARATION FROM ONE ANOTHER NOT SUBSTANTIALLY LESS THAN THAT ASSUMED BY SAID FIBERS IN THE WET MOLDED OBJECT.
References Cited (Backward Citations)
CA582773A
Cited
US1827203A
Cited
US2137404A
Cited
US2444124A
Cited
US2517799A
Cited
US2763267A
Cited
US2759222A
Cited
US2723971A
Cited
US2739598A
Cited
US2806474A
Cited
US3023075A
Cited
US2812767A
Cited
US3003504A
Cited
US3104198A
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US3137664A
Cited
US3116199A
Cited
US3201505A
Cited
US3167522A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1969-06-13 | 1969-12-13 | 1970-06-14 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1973-06-13 | 1973-12-13 | 1974-06-14 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1977-06-13 | 1977-12-13 | 1978-06-14 | $7700.00 | Window Closed / Lapsed |