Patent US3709778A successfully refreshed from Google Patents.
US3709778A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method for bleaching groundwood pulp with tertiary butyl hydroperoxide
Assignee: Atlantic Richfield Co
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Filing: 1971-01-12
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Granted: 1973-01-09
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Expires: 1991-01-12
Abstract
Abstract Bleaching of ligneous cellulosic materials such as groundwood pulp by treating the pulp with an aqueous solution of tertiary butyl hydroperoxide and a buffering agent and thereafter contacting the pulp with a sulfite compound.
Inventors
- 👤 R Lincoln
- 👤 J Meyers
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 10:04
CPC Classifications
D; D21; D21C; D21C9/00; D21C9/10; D21C9/16; D21C9/163
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
13 words
The method according to Claim 1, wherein said buffer-ing agent is sodium carbonate.
Claim 2
Dependent Claim
13 words
The method according to Claim 1, wherein said buffer-ing agent is sodium bicarbonate.
Claim 3
Dependent Claim
16 words
The method according to Claim 1, wherein said buffer-ing agent is sodium tripolyphosphate and a surfactant.
Claim 4
Dependent Claim
25 words
The method according to Claim 4, wherein said surfactant is a linear alkylbenzene sulfonate wherein the alkyl group contains from 11 to 14 carbon atoms.
Claim 5
Dependent Claim
16 words
The method according to claim 1, wherein said sulfite compound is sodium sulfite or sodium bisulfite.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-01-09 | 1976-07-10 | 1977-01-09 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-01-09 | 1980-07-10 | 1981-01-09 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-01-09 | 1984-07-10 | 1985-01-09 | $7700.00 | Window Closed / Lapsed |