US2668095A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Bleaching chemical paper pulp
Assignee: EIDP Inc
•
Filing: 1950-09-22
•
Granted: 1954-02-02
•
Expires: 1970-09-22
Abstract
No abstract record available.
Inventors
- 👤 Francis L Fennell
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 01:44
CPC Classifications
D; D21; D21C; D21C9/00; D21C9/10; D21C9/1057
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
66 words
IN A PROCESS FOR BLEACHING CHEMICAL WOOD PULPS WHEREIN THE PULP IS TREATED UNDER ALKALINE CONDITIONS WITH A CALCIUM COMPOUND YIELDING CALCIUM IONS AND THEN TREATED WITH ALKALINE PEROXIDE, THE IMPROVEMENT COMPRISING ACIDIFYING SAID PULP INTERMEDIATE SAID TREATMENTS, WITHOUT SIMULTANEOUSLY BLEACHING SAID PULP TO ANY SUBSTANTIAL EXTENT, WITH AN AGENT FROM THE GROUP CONSISTING OF HYDROCHLORIC ACID AND CHLORINE TO A PH NOT HIGHER THAN 6.
Claim 2
Dependent Claim
66 words
IN A PROCESS FOR BLEACHING CHEMICAL WOOD PULPS WHEREIN THE PULP IS TREATED UNDER ALKALINE CONDITIONS WITH A CALCIUM COMPOUND YIELDING CALCIUM IONS AND THEN TREATED WITH ALKALINE PEROXIDE, THE IMPROVEMENT COMPRISING ACIDIFYING SAID PULP INTERMEDIATE SAID TREATMENTS, WITHOUT SIMULTANEOUSLY BLEACHING SAID PULP TO ANY SUBSTANTIAL EXTENT, WITH AN AGENT FROM THE GROUP CONSISTING OF HYDROCHLORIC ACID AND CHLORINE TO A PH NOT HIGHER THAN 6.
References Cited (Backward Citations)
US1768823A
Cited
DE573341C
Cited
US1771064A
Cited
US1827857A
Cited
US2026068A
Cited
US2083280A
Cited
US2140863A
Cited
US2203212A
Cited
US2494542A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1957-02-01 | 1957-08-03 | 1958-02-02 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1961-02-01 | 1961-08-03 | 1962-02-02 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1965-02-01 | 1965-08-03 | 1966-02-02 | $7700.00 | Window Closed / Lapsed |