US3960649A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Wood pulp bleaching composition containing sodium hydrosulfite and hexamethylenetetramine
Assignee: Ventron Corp
•
Filing: 1975-04-18
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Granted: 1976-06-01
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Expires: 1995-04-18
Abstract
Abstract An aqueous composition for bleaching wood pulp containing sodium hydrosulfite, and at least 2 weight percent hexamethylenetetramine based upon the weight of sodium hydrosulfite, wherein the solution has a pH between about 4 and about 11. The hexamethylenetetramine prevents hydrogen sulfide formation during bleaching of the wood pulp.
Inventors
- 👤 Edward A. Sullivan
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 14:17
CPC Classifications
D; D21; D21C; D21C9/00; D21C9/10; D21C9/1084; D21C9/1089
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
59 words
A wood pulp bleaching composition which comprises an aqueous solution for sodium hydrosulfite, and at least 2 weight percent hexamethylenetetramine based upon the weight of sodium hydrosulfite, said solution having a pH between about 5.0 and about 11.0 and said weight percent of hexamethylenetetramine being effective to prevent formation of hydrogen sulfide during sodium hydrosulfite bleaching of wood pulp.
Claim 2
Dependent Claim
59 words
A wood pulp bleaching composition which comprises an aqueous solution for sodium hydrosulfite, and at least 2 weight percent hexamethylenetetramine based upon the weight of sodium hydrosulfite, said solution having a pH between about 5.0 and about 11.0 and said weight percent of hexamethylenetetramine being effective to prevent formation of hydrogen sulfide during sodium hydrosulfite bleaching of wood pulp.
Claim 3
Dependent Claim
21 words
The composition of claim 1 containing between about 5 and 25 weight percent hexamethylenetetramine based upon the weight of sodium hydrosulfite.
Claim 4
Dependent Claim
9 words
The composition of claim 1 which contains sodium borate.
Claim 5
Dependent Claim
9 words
The composition of claim 2 which contains sodium borate.
Claim 6
Dependent Claim
30 words
The composition of claim 1 which contains wood pulp wherein the concentration of sodium hydrosulfite is between about 0.1 and 3.0 weight percent based upon the weight of wood pulp.
Claim 7
Dependent Claim
30 words
The composition of claim 2 which contains wood pulp wherein the concentration of sodium hydrosulfite is between about 0.1 and 3.0 weight percent based upon the weight of wood pulp.
Claim 8
Dependent Claim
30 words
The composition of claim 3 which contains wood pulp wherein the concentration of sodium hydrosulfite is between about 0.1 and 3.0 weight percent based upon the weight of wood pulp.
Claim 9
Dependent Claim
30 words
The composition of claim 4 which contains wood pulp wherein the concentration of sodium hydrosulfite is between about 0.1 and 3.0 weight percent based upon the weight of wood pulp.
References Cited (Backward Citations)
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Cited
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Cited
US2525770A
Cited
US2707145A
Cited
US3653804A
Cited
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Cited
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Cited
US3923960A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1979-06-01 | 1979-12-01 | 1980-06-01 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1983-06-01 | 1983-12-01 | 1984-06-01 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1987-06-01 | 1987-12-01 | 1988-06-01 | $7700.00 | Window Closed / Lapsed |