Patent EP0329475A2 successfully refreshed from Google Patents.
Patent US3190789A successfully refreshed from Google Patents.
US3190789A
Expired / Lapsed
US
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Calcium silicate-filled paper
Assignee: PITTSBURGH PIATE GLASS Co
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Filing: 1960-02-18
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Granted: 1965-06-22
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Expires: 1980-02-18
Abstract
No abstract record available.
Inventors
- 👤 Louis B Taylor
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 09:35
CPC Classifications
D; D21; D21H; D21H17/00; D21H17/63; D21H17/70; D21H17/67; D21H17/68
Claims Analysis
Total Claims: 3
Claim 1
Independent Claim
71 words
IN A PROCESS FOR THE MANUFACTURE OF PAPER, WHEREIN A FURNISH IS PREPARED, THE STEP WHICH COMPRISES ADDING TO SAID FURNISH A HYDRATED CALCIUM SILICATE PIGMENT HAVING AN SIO2/CAO MOLE RATIO LIMITED BY A MAXIMUM VALUE OF ABOUT 5:1 AND A BOUND WATER CONTENT LIMITED BY A MAXIMUM VALUE OF ABOUT 15 PERCENT BY WEIGHT OF SAID PIGMENT AND ADJUSTING THE PH TO A VALUE WITHIN THE RANGE OF ABOUT 4.5-6.5.
Claim 2
Dependent Claim
86 words
IN A PAPER PRODUCT WHICH IS PREPARED BY FORMING A SHEET FROM A FURNISH COMPRISING PULP, SIZING MATERIAL AND A FILLER AND SUBSEQUENTLY DRYING AID SHEET, THE IMPROVEMENT WHICH COMPRISES EMPLOYING AS A FILLER A CALCIUM SILICATE PIGMENT HAVING AN SIO2/CAO MOLE RATIO LIMITED BY A MAXIMUM VALUE OF ABOUT 5:1 AND A BOUND WATER CONTENT LIMITED BY A MAXIMUM VALUE OF ABOUT 15 PERCENT BY WEIGHT OF SAID PIGMENT AND ADJUSTING THE PH OF SAID FURNISH TO A VALUE WITHIN THE RANGE OF ABOUT 4.5-6.5.
Claim 3
Dependent Claim
53 words
A PAPER FURNISH HAVING A PH WITHIN THE RANGE OF ABOUT 4.5-6.5 COMPRISING AS A FILLER A HYDRATED CALCIUM SILICATE PIGMENT HAVING AN SIO2/CAO MOLE RATIO LIMITED BY A MAXIMUM VALUE OF ABOUT 5:1 AND A BOUND WATER CONTENT LIMITED BY A MAXIMUM VALUE OF ABOUT 15 PERCENT BY WEIGHT OF SAID PIGMENT.
References Cited (Backward Citations)
GB381697A
Cited
US2237374A
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US2247355A
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US2554934A
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US2599094A
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US2739068A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1968-06-21 | 1968-12-21 | 1969-06-22 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1972-06-21 | 1972-12-21 | 1973-06-22 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1976-06-21 | 1976-12-21 | 1977-06-22 | $7700.00 | Window Closed / Lapsed |