US3186899A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Groundwood pulp
Assignee: Minnesota and Ontario Paper Co
•
Filing: 1962-09-11
•
Granted: 1965-06-01
•
Expires: 1982-09-11
Abstract
No abstract record available.
Inventors
- 👤 Elmo H Madison
- 👤 William H Mcpherson
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 13:43
CPC Classifications
D; D21; D21B; D21B1/00; D21B1/04; D21B1/12; D21B1/14; D21B1/16
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
148 words
THE METHOD OF PRODUCING WOOD PULP FROM HARDWOOD WHICH COMPRISES STONE GRINDING WOOD TO A COARSE PULP STOCK TOO COARSE FOR THE COARSEST GRADE OF PAPER AND HAVING A CANADIAN STANDARD FREENESS OF ABOUT 500 TO ABOUT 750 CC., MIXING ABOUT 3% TO ABOUT 7% OF CAUSTIC SODA WITH THE STOCK IN WATER, HOLDING THE STOCK WITH THE CAUSTIC SODA MIXTED THEREWITH FOR A PERIOD NOT EXCEEDING ABOUT 30 MINUTES AND NOT LESS THAN ABOUT FOUR MINUTES, DISC REFINING THE STOCK IN THE PRESENCE OF CAUSTIC SODA IN WATER TO ABOUT 300 TO ABOUT 400 CC. CANADIAN STANDARD FREENESS STORING THE STOCK SLURRY FROM THE MECHANICAL REFINING FOR A PERIOD OF ABOUT 20 MINUTES TO ABOUT 60 MINUTES, THEN WASHING THE STOCK WITH WATER AND SUBJECTING THE WASHED STOCK TO A SECOND MECHANICAL REFINING TO PROVIDE A PULP OF ABOUT 100 TO ABOUT 200 CC. CANADIAN STANDARD FREENESS.
Claim 2
Independent Claim
148 words
THE METHOD OF PRODUCING WOOD PULP FROM HARDWOOD WHICH COMPRISES STONE GRINDING WOOD TO A COARSE PULP STOCK TOO COARSE FOR THE COARSEST GRADE OF PAPER AND HAVING A CANADIAN STANDARD FREENESS OF ABOUT 500 TO ABOUT 750 CC., MIXING ABOUT 3% TO ABOUT 7% OF CAUSTIC SODA WITH THE STOCK IN WATER, HOLDING THE STOCK WITH THE CAUSTIC SODA MIXTED THEREWITH FOR A PERIOD NOT EXCEEDING ABOUT 30 MINUTES AND NOT LESS THAN ABOUT FOUR MINUTES, DISC REFINING THE STOCK IN THE PRESENCE OF CAUSTIC SODA IN WATER TO ABOUT 300 TO ABOUT 400 CC. CANADIAN STANDARD FREENESS STORING THE STOCK SLURRY FROM THE MECHANICAL REFINING FOR A PERIOD OF ABOUT 20 MINUTES TO ABOUT 60 MINUTES, THEN WASHING THE STOCK WITH WATER AND SUBJECTING THE WASHED STOCK TO A SECOND MECHANICAL REFINING TO PROVIDE A PULP OF ABOUT 100 TO ABOUT 200 CC. CANADIAN STANDARD FREENESS.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1968-05-31 | 1968-11-30 | 1969-06-01 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1972-05-31 | 1972-11-30 | 1973-06-01 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1976-05-31 | 1976-11-30 | 1977-06-01 | $7700.00 | Window Closed / Lapsed |