US2980558A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Process of impregnating paper with silica sols
Assignee: EIDP Inc
•
Filing: 1958-05-29
•
Granted: 1961-04-18
•
Expires: 1978-05-29
Abstract
No abstract record available.
Inventors
- 👤 Donald F Dempey
- 👤 Joseph M Rulc
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 13:01
CPC Classifications
D; D21; D21H; D21H17/00; D21H17/63; D21H17/67; D21H17/68
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
80 words
IN A PROCESS FOR IMPROVING PAPER THE STEPS COMPRISING IMPREGNATING THE PAPER WITH AN ESSENTIALLY SALTFREE SOL OF ACTIVE, NON AGGREGATED SILICA AT A PH BELOW 6.0, THE SOL HAVING AN SIO2 CONTENT NOT EXCEEDING 15% BY WEIGHT AND SAID SILICA BEING IN THE FORM OF PARTICLES HAVING A SIZE NOT EXCEEDING 7 MILLIMICRONS, AND DRYING THE IMPREGNATED PRODUCT, THE AMOUNT OF SILICA DEPOSITED IN THE PAPER BEING AT LEAST 0.5% BASED ON THE DRIED WEIGHT OF THE TREATED PRODUCT.
Claim 2
Dependent Claim
80 words
IN A PROCESS FOR IMPROVING PAPER THE STEPS COMPRISING IMPREGNATING THE PAPER WITH AN ESSENTIALLY SALTFREE SOL OF ACTIVE, NON AGGREGATED SILICA AT A PH BELOW 6.0, THE SOL HAVING AN SIO2 CONTENT NOT EXCEEDING 15% BY WEIGHT AND SAID SILICA BEING IN THE FORM OF PARTICLES HAVING A SIZE NOT EXCEEDING 7 MILLIMICRONS, AND DRYING THE IMPREGNATED PRODUCT, THE AMOUNT OF SILICA DEPOSITED IN THE PAPER BEING AT LEAST 0.5% BASED ON THE DRIED WEIGHT OF THE TREATED PRODUCT.
References Cited (Backward Citations)
US2244325A
Cited
US2408656A
Cited
US2441422A
Cited
US2441423A
Cited
US2457971A
Cited
US2577485A
Cited
US2801938A
Cited
US2892797A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1964-04-17 | 1964-10-17 | 1965-04-18 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1968-04-17 | 1968-10-17 | 1969-04-18 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1972-04-17 | 1972-10-17 | 1973-04-18 | $7700.00 | Window Closed / Lapsed |