Patent US3180787A successfully refreshed from Google Patents.
US3180787A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Process for making high flexural strength paper
Assignee: Primerica Inc
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Filing: 1959-05-20
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Granted: 1965-04-27
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Expires: 1979-05-20
Abstract
No abstract record available.
Inventors
- 👤 James W Adams
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 19:53
CPC Classifications
D; D21; D21H; D21H17/00; D21H17/20; D21H17/21; D21H17/23
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
92 words
A METHOD FOR INCREASING THE FLEXURAL STRENGTH OF PAPER WHICH COMPRISES ADDING A WATER SOUBLE LIGNOSULFONATE SALT TO A WATER SLURRY OF CELLULOSE PULP IN AN AMOUNT BETWEEN 10% AND 150% OF THE DRY WEIGHT OF SAID PULP, ADDING A POLYETHYLENE POLYAMINE HAVING A MOLECULAR WEIGHT IN EXCESS OF 150 IN AN AMOUNT BETWEEN 1% AND 10% OF THE DRY WEIGHT OF SAID CELLULOSE PULP THEREBY PRECIPITATING INSOLUBLE POLYETHYLENE POLYAMINE LIGNOSULFONATE IN INTIMATE ADMISTURE WITH SAID CELLULOSE PULP, AND FORMING THE PULP FIBERS WITH ADHERED INSOLUBLE PRECIPITATE INTO A CONTINUOUS PAPER WEB.
Claim 2
Independent Claim
92 words
A METHOD FOR INCREASING THE FLEXURAL STRENGTH OF PAPER WHICH COMPRISES ADDING A WATER SOUBLE LIGNOSULFONATE SALT TO A WATER SLURRY OF CELLULOSE PULP IN AN AMOUNT BETWEEN 10% AND 150% OF THE DRY WEIGHT OF SAID PULP, ADDING A POLYETHYLENE POLYAMINE HAVING A MOLECULAR WEIGHT IN EXCESS OF 150 IN AN AMOUNT BETWEEN 1% AND 10% OF THE DRY WEIGHT OF SAID CELLULOSE PULP THEREBY PRECIPITATING INSOLUBLE POLYETHYLENE POLYAMINE LIGNOSULFONATE IN INTIMATE ADMISTURE WITH SAID CELLULOSE PULP, AND FORMING THE PULP FIBERS WITH ADHERED INSOLUBLE PRECIPITATE INTO A CONTINUOUS PAPER WEB.
References Cited (Backward Citations)
US2492702A
Cited
US2297635A
Cited
US2601597A
Cited
US2622979A
Cited
US2683706A
Cited
US2849314A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1968-04-26 | 1968-10-26 | 1969-04-27 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1972-04-26 | 1972-10-26 | 1973-04-27 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1976-04-26 | 1976-10-26 | 1977-04-27 | $7700.00 | Window Closed / Lapsed |