US4227964A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method of treating lignocellulosic or cellulosic pulp to promote the kinking of pulp fibres and/or to improve paper tear strength
Assignee: Individual
•
Filing: 1979-03-26
•
Granted: 1980-10-14
•
Expires: 1999-03-26
Abstract
Abstract The invention relates to a process comprising the saturation of a lignocellulosic or cellulosic pulp in gaseous ammonia. In one embodiment this is followed by subjection of the saturated pulp to vacuum. The treatment promotes the kinking of pulp fibres and/or improves the tearing strength of paper prepared therefrom.
Inventors
- 👤 Allan J. Kerr
- 👤 Robert P. Kibblewhite
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 15:39
CPC Classifications
D; D21; D21C; D21C9/00; D21C9/001; D21C9/002; D21C9/004
Claims Analysis
Total Claims: 22
Claim 1
Independent Claim
110 words
A method of kinking pulp fibers in order to increase the tear strength of papers made from such fibers, wherein the pulp is a lignocellulosic or cellulosic pulp derived from a chemical, semichemical or chemimechanical pulping process, said method comprising kinking pulp fibers having a consistency of approximately 15 up to approximately 400 weight percent of dried pulp in the total material, water plus pulp, while substantially maintaining pulp yield by treating the pulp with gaseous ammonia at a pressure of at least one atmosphere until at least 9% by weight, based on the weight of oven dried pulp, of gaseous ammonia has been taken up by the moist pulp.
Claim 2
Independent Claim
110 words
A method of kinking pulp fibers in order to increase the tear strength of papers made from such fibers, wherein the pulp is a lignocellulosic or cellulosic pulp derived from a chemical, semichemical or chemimechanical pulping process, said method comprising kinking pulp fibers having a consistency of approximately 15 up to approximately 400 weight percent of dried pulp in the total material, water plus pulp, while substantially maintaining pulp yield by treating the pulp with gaseous ammonia at a pressure of at least one atmosphere until at least 9% by weight, based on the weight of oven dried pulp, of gaseous ammonia has been taken up by the moist pulp.
Claim 3
Dependent Claim
13 words
The method according to claim 1 wherein said pulp is a softwood pulp.
Claim 4
Dependent Claim
18 words
The method according to claim 1 wherein said pulp is derived in a yield of up to 80%.
Claim 5
Dependent Claim
21 words
The method according to claim 1 wherein said pulp is a semi-chemical pulp derived in a yield of up to 75%.
Claim 6
Dependent Claim
22 words
The method according to claim 1 wherein said pulp is produced by a bisulphite process in a yield of up to 75%.
Claim 7
Dependent Claim
13 words
The method according to claim 1 wherein said pulp is a chemical pulp.
Claim 8
Dependent Claim
28 words
The method according to claim 1 wherein said pulp has a consistency of up to 30 weight percent of dried pulp in the total material, water plus pulp.
Claim 9
Dependent Claim
18 words
The method according to claim 1 wherein said treatment with gaseous ammonia is followed by a pressure release.
Claim 10
Dependent Claim
28 words
The method according to claim 8 wherein said treatment with gaseous ammonia is carried out in a cyclical manner with a pressure phase followed by a pressure release.
Claim 11
Dependent Claim
25 words
The method according to claim 9 including up to five pressure phases alternating with pressure release phases of up to 1 hour between each phases.
Claim 12
Dependent Claim
18 words
The method according to claim 10 wherein each said pressure phase is applied for up to 2 hours.
Claim 13
Dependent Claim
19 words
The method according to claim 1 wherein said pulp is refined prior to said treatment with said gaseous ammonia.
Claim 14
Dependent Claim
19 words
The method according to claim 1 wherein said pulp is not refined prior to said treatment with gaseous ammonia.
Claim 15
Dependent Claim
18 words
The method according to claim 1 wherein said pulp is bleached prior to said treatment with gaseous ammonia.
Claim 16
Dependent Claim
17 words
The method according to claim 1 wherein said pulp is bleached following said treatment with gaseous ammonia.
Claim 17
Dependent Claim
21 words
The method according to claim 1 wherein said treatment with gaseous ammonia is carried out at a temperature of 0-150° C.
Claim 18
Dependent Claim
27 words
Method according to claim 1 wherein said pulp is a chemical pulp produced by a process selected from the group consisting of Kraft-type processes and soda-oxygen-type processes.
Claim 19
Dependent Claim
20 words
Method according to claim 1 wherein said treatment with gaseous ammonia is followed by subjecting said pulp to a vacuum.
Claim 20
Dependent Claim
27 words
Method according to claim 18 wherein said treatment with gaseous ammonia is carried out in a cyclical manner with a pressure phase followed by a vacuum phase.
Claim 21
Dependent Claim
22 words
Method according to claim 19 including up to 5 pressure phases alternating with vacuum phases of up to one hour between phases.
Claim 22
Dependent Claim
13 words
Method according to claim 1 wherein said pressure is up to 15 atmospheres.
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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) | 1983-10-14 | 1984-04-14 | 1984-10-14 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1987-10-14 | 1988-04-14 | 1988-10-14 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1991-10-14 | 1992-04-14 | 1992-10-14 | $7700.00 | Window Closed / Lapsed |