US4475984A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Process for pretreating wood chips with monoperoxy sulfuric acid or its salts prior to alkaline pulping
Assignee: International Paper Co
•
Filing: 1983-06-20
•
Granted: 1984-10-09
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Expires: 2003-06-20
Abstract
Abstract Treatment of lignocellulosic materials with monoperoxysulfate to permit more ready separation of non-cellulosic materials therefrom to produce papermaking pulps is disclosed.
Inventors
- 👤 John J. Cael
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 07:22
CPC Classifications
D; D21; D21C; D21C9/00; D21C9/10; D21C9/16
Claims Analysis
Total Claims: 3
Claim 1
Independent Claim
95 words
A process for pulping wood chips comprising pretreating said wood chips with monoperoxy sulfuric acid or its salts at a pH within the range from about 2.0 to 12.0, wherein the pretreatment comprises a treatment time within the range about of 1 to about 72 hours at a temperature within the range from about 20° C. to about 70° C. and an amount of persulfate ion based on the oven dry weight of wood chips from about 0.35 percent to about 35 percent; following said pretreatment subjecting said pretreated chips to an alkaline pulping process.
Claim 2
Dependent Claim
95 words
A process for pulping wood chips comprising pretreating said wood chips with monoperoxy sulfuric acid or its salts at a pH within the range from about 2.0 to 12.0, wherein the pretreatment comprises a treatment time within the range about of 1 to about 72 hours at a temperature within the range from about 20° C. to about 70° C. and an amount of persulfate ion based on the oven dry weight of wood chips from about 0.35 percent to about 35 percent; following said pretreatment subjecting said pretreated chips to an alkaline pulping process.
Claim 3
Dependent Claim
16 words
A process as defined in claim 1 wherein the persulfate ion is supplied by potassium peroxydisulfate.
References Cited (Backward Citations)
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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) | 1987-10-09 | 1988-04-09 | 1988-10-09 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1991-10-09 | 1992-04-09 | 1992-10-09 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1995-10-09 | 1996-04-09 | 1996-10-09 | $7700.00 | Window Closed / Lapsed |