US4976819A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Pulp treatment methods
Assignee: PotlatchDeltic Corp
•
Filing: 1988-04-28
•
Granted: 1990-12-11
•
Expires: 2008-04-28
Abstract
Abstract Mechanical treatment of a pulp slurry of up to 50% O.D. consistency by dewatering and compacting the pulp permanently twists and kinks individual fibers to a degree that is substantially irreversible when they are subsequently subjected to papermaking process steps. The preferred device for imparting such permanent twisting and kinking is a plug screw feeder. Pulp that has been so treated exhibits increased desired drainability in the wet section of a papermachine. Such treated pulp also loses water vapor more easily in the dryer section than untreated pulp, and correspondingly results in less energy consumption in the dryer section of a papermachine. Pulp treated in accordance with the invention also exhibits increased absorbency. Tissue or other soft paper products produced from softwood pulp treated in accordance with the invention exhibit significantly increased softness over such untreated softwood pulp. Pulp treated in accordance with the invention is also useful in enhancing properties, for example bulk, in other paper products.
Inventors
- 👤 Mary L. Minton
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 07:48
CPC Classifications
D; D21; D21C; D21C9/00; D21C9/001; D21C9/007; D21H; D21H15/00; D21H15/02; D21H15/04
Claims Analysis
Total Claims: 32
Claim 1
Independent Claim
126 words
A method for producing improved soft paper products by mechanically treating pulp of up to 50% O.D. consistency, comprising the steps of: wringing, dewatering and compacting the pulp of up to 50% O.D. consistency to permanently twist and kink individual fibers to a degree that is substantially irreversible when they are subsequently subjected to papermaking process steps, the treated pulp having, (a) increased freeness; (b) reduced tensile strength; (c) increased bulk; (d) reduced tearing resistance; and (e) greater softness, over the same pulp that has not been so mechanically treated; and feeding the treated pulp into a headbox of a papermaking machine to produce a paper product having greater softness than a paper product made from the same pulp that has not been so mechanically treated.
Claim 2
Independent Claim
126 words
A method for producing improved soft paper products by mechanically treating pulp of up to 50% O.D. consistency, comprising the steps of: wringing, dewatering and compacting the pulp of up to 50% O.D. consistency to permanently twist and kink individual fibers to a degree that is substantially irreversible when they are subsequently subjected to papermaking process steps, the treated pulp having, (a) increased freeness; (b) reduced tensile strength; (c) increased bulk; (d) reduced tearing resistance; and (e) greater softness, over the same pulp that has not been so mechanically treated; and feeding the treated pulp into a headbox of a papermaking machine to produce a paper product having greater softness than a paper product made from the same pulp that has not been so mechanically treated.
Claim 3
Dependent Claim
26 words
The method of claim 1 wherein the step of wringing, dewatering and compacting the pulp comprises moving the pulp along an annular path of decreasing volume.
Claim 4
Dependent Claim
23 words
The method of claim 2 wherein the step of wringing, dewatering and compacting the pulp comprises passing the pulp through a plug-screw feeder.
Claim 5
Dependent Claim
18 words
The method of claim 3 further comprising: restricting the flow of pulp exiting from the plug screw feeder.
Claim 6
Dependent Claim
59 words
The method of claim 1 further comprising, before said feeding, the steps of, diluting the treated fiber pulp to a more fluid consistency; and agitating the diluted pulp for a sufficient time at a sufficient temperature to substantially individually suspend the kinked and twisted fibers and to break up any clumps of fibers created during the mechanical treating step.
Claim 7
Dependent Claim
15 words
The method of claim 1 wherein wringing, dewatering and compacting of the pulp occur simultaneously.
Claim 8
Independent Claim
84 words
A method of manipulating pulp comprising the steps of: mechanically treating pulp of up to 50% O.D. consistency by wringing, dewatering and compacting the pulp to permanently twist and kink individual fibers to a degree that is substantially irreversible when they are subsequently subjected to papermaking process steps, the treated pulp having increased freeness and thereby increased drainability in the wet sections of a paper machine over the same pulp that has not been wrung, dewatered and compacted to twist and kink individual fibers.
Claim 9
Independent Claim
84 words
A method of manipulating pulp comprising the steps of: mechanically treating pulp of up to 50% O.D. consistency by wringing, dewatering and compacting the pulp to permanently twist and kink individual fibers to a degree that is substantially irreversible when they are subsequently subjected to papermaking process steps, the treated pulp having increased freeness and thereby increased drainability in the wet sections of a paper machine over the same pulp that has not been wrung, dewatered and compacted to twist and kink individual fibers.
Claim 10
Dependent Claim
26 words
The method of claim 7 wherein the step of wringing, dewatering and compacting the pulp comprises moving the pulp along an annular path of decreasing volume.
Claim 11
Dependent Claim
23 words
The method of claim 8 wherein the step of wringing, dewatering and compacting the pulp comprises passing the pulp through a plug-screw feeder.
Claim 12
Dependent Claim
18 words
The method of claim 9 further comprising: restricting the flow of pulp exiting from the pulp screw feeder.
Claim 13
Dependent Claim
15 words
The method of claim 7 wherein wringing, dewatering and compacting of the pulp occur simultaneously.
Claim 14
Independent Claim
123 words
A method for producing improved absorbent paper products by mechanically treating pulp of up to 50% O.D. consistency, comprising the steps of: wringing, dewatering and compacting the pulp of up to 50% O.D. consistency to permanently twist and kink individual fibers to a degree that is substantially irreversible when they are subsequently subjected to papermaking process steps, the treated pulp having, (a) reduced tensile strength; (b) increased bulk; (c) reduced tearing resistance; and (d) greater absorbency, over the same pulp that has not been so mechanically treated; and feeding the treated pulp into a headbox of a papermaking machine to produce a paper product having greater abosrbency than a paper product made from the same pulp that has not been so mechanically treated.
Claim 15
Independent Claim
123 words
A method for producing improved absorbent paper products by mechanically treating pulp of up to 50% O.D. consistency, comprising the steps of: wringing, dewatering and compacting the pulp of up to 50% O.D. consistency to permanently twist and kink individual fibers to a degree that is substantially irreversible when they are subsequently subjected to papermaking process steps, the treated pulp having, (a) reduced tensile strength; (b) increased bulk; (c) reduced tearing resistance; and (d) greater absorbency, over the same pulp that has not been so mechanically treated; and feeding the treated pulp into a headbox of a papermaking machine to produce a paper product having greater abosrbency than a paper product made from the same pulp that has not been so mechanically treated.
Claim 16
Dependent Claim
26 words
The method of claim 12 wherein the step of wringing, dewatering and compacting the pulp comprises moving the pulp along an annular path of decreasing volume.
Claim 17
Dependent Claim
23 words
The method of claim 13 wherein the step of wringing, dewatering and compacting the pulp comprises passing the pulp through a plug-screw feeder.
Claim 18
Dependent Claim
18 words
The method of claim 14 further comprising: restricting the flow of pulp exiting from the plug screw feeder.
Claim 19
Dependent Claim
15 words
The method of claim 12 wherein wringing, dewatering and compacting of the pulp occur simultaneously.
Claim 20
Independent Claim
72 words
A method of manipulating pulp comprising the steps of: mechanically treating pulp of up to 50% O.D. consistency by wringing, dewatering and compacting the pulp to permanently twist and kink individual fibers to a degree that is substantially irreversible when they are subsequently subjected to papermaking process steps, the treated pulp having increased bulk over the same pulp that has not been wrung, dewatered and compacted to twist and kink individual fibers.
Claim 21
Independent Claim
72 words
A method of manipulating pulp comprising the steps of: mechanically treating pulp of up to 50% O.D. consistency by wringing, dewatering and compacting the pulp to permanently twist and kink individual fibers to a degree that is substantially irreversible when they are subsequently subjected to papermaking process steps, the treated pulp having increased bulk over the same pulp that has not been wrung, dewatered and compacted to twist and kink individual fibers.
Claim 22
Dependent Claim
24 words
The method of claim 17 wherein wringing, dewatering and compacting of the pulp comprises moving the pulp along an annular path of decreasing volume.
Claim 23
Dependent Claim
22 words
The method of claim 18 wherein wringing, dewatering and compacting of the pulp comprises passing the pulp through a plug screw feeder.
Claim 24
Dependent Claim
18 words
The method of claim 19 further comprising: restricting the flow of pulp exiting from the plug screw feeder.
Claim 25
Dependent Claim
15 words
The method of claim 17 wherein wringing, dewatering and compacting of the pulp occur simultaneously.
Claim 26
Independent Claim
147 words
A method for producing improved soft paper products by mechanically treating pulp of up to 50% O.D. consistency, comprising the steps of: wringing, dewatering and compacting the pulp of up to 50% O.D. consistency to permanently twist and kink individual fibers to a degree that is substantially irreversible when they are subsequently subjected to papermaking process steps, the treated pulp having, (a) increased freenes of at least 5%; (b) reduced tensile strength of at least 30%; (c) increased bulk of at least 20%; (d) reduced tearing resistance of at least 10%; and (e) greater absorbency; (f) greater softness, over the same pulp that has not been so mechanically treated; and feeding the treated pulp into a headbox of a papermaking machine to produce a paper product having greater softness and absorbency than a paper product made from the same pulp that has not been so mechanically treated.
Claim 27
Independent Claim
147 words
A method for producing improved soft paper products by mechanically treating pulp of up to 50% O.D. consistency, comprising the steps of: wringing, dewatering and compacting the pulp of up to 50% O.D. consistency to permanently twist and kink individual fibers to a degree that is substantially irreversible when they are subsequently subjected to papermaking process steps, the treated pulp having, (a) increased freenes of at least 5%; (b) reduced tensile strength of at least 30%; (c) increased bulk of at least 20%; (d) reduced tearing resistance of at least 10%; and (e) greater absorbency; (f) greater softness, over the same pulp that has not been so mechanically treated; and feeding the treated pulp into a headbox of a papermaking machine to produce a paper product having greater softness and absorbency than a paper product made from the same pulp that has not been so mechanically treated.
Claim 28
Dependent Claim
15 words
The method of claim 22 wherein wringing, dewatering and compacting of the pulp occur simultaneously.
Claim 29
Independent Claim
201 words
A method of treating pulp to produce an improved soft paper product, the pulp consisting essentially of chemical pulp, the method comprising the steps of: preparing chemical pulp to obtain a consistency of from 5% to 20% O.D.; passing the 5% to 20% O.D. chemical pulp through a plug screw feeder having a nominal compression ratio of at least 2.0 to 1 to wring, dewater and compact the pulp and to permanently twist and kink individual fibers to a degree that is substantially irreversible when they are subsequently subjected to papermaking process steps, and thus producing a treated chemical pulp; restricting the flow of the treated chemical pulp exiting from the plug screw feeder; the treated chemical pulp existing the restricted plug screw feeder having, (a) increased freeness; (b) reduced tensile strength; (c) increased bulk; (d) reduced tearing resistance; and (e) greater softness, than the same pulp which has not been passed through a plug screw feeder to twist and kink individual fibers; and feeding the treated chemical pulp into a headbox of a papermaking machine to produce a paper product having greater softness than a paper product made from the same chemical pulp that has not been so mechanically treated.
Claim 30
Independent Claim
201 words
A method of treating pulp to produce an improved soft paper product, the pulp consisting essentially of chemical pulp, the method comprising the steps of: preparing chemical pulp to obtain a consistency of from 5% to 20% O.D.; passing the 5% to 20% O.D. chemical pulp through a plug screw feeder having a nominal compression ratio of at least 2.0 to 1 to wring, dewater and compact the pulp and to permanently twist and kink individual fibers to a degree that is substantially irreversible when they are subsequently subjected to papermaking process steps, and thus producing a treated chemical pulp; restricting the flow of the treated chemical pulp exiting from the plug screw feeder; the treated chemical pulp existing the restricted plug screw feeder having, (a) increased freeness; (b) reduced tensile strength; (c) increased bulk; (d) reduced tearing resistance; and (e) greater softness, than the same pulp which has not been passed through a plug screw feeder to twist and kink individual fibers; and feeding the treated chemical pulp into a headbox of a papermaking machine to produce a paper product having greater softness than a paper product made from the same chemical pulp that has not been so mechanically treated.
Claim 31
Independent Claim
205 words
A method of treating pulp to produce an improved soft paper product, the pulp consisting essentially of softwood chemical pulp, the method comprising the steps of: preparing softwood chemical pulp to obtain a consistency of from 5% to 50% O.D.; passing the 5% to 50% O.D. softwood chemical pulp through a plug screw feeder having a nominal compression ratio of at least 2.0 to 1 to wring, dewater and compact the pulp and to permanently twist and kink individual fibers to a degree that is substantially irreversible when they are subsequently subjected to papermaking process steps, and thus producing a treated softwood chemical pulp; restricting the flow of the treated softwood chemical pulp exiting from the plug screw feeder; the treated softwood chemical pulp having, (a) increased freeness; (b) reduced tensile strength; (c) increased bulk; (d) reduced tearing resistance; and (e) greater softness, than the same softwood chemical pulp which has not been passed through a plug screw feeder to twist and kink individual fibers; and feeding the treated softwood chemical pulp into a headbox of a papermaking machine to produce a paper product having greater softness than a paper product made from the same softwood chemical pulp that has not been so mechanically treated.
Claim 32
Independent Claim
205 words
A method of treating pulp to produce an improved soft paper product, the pulp consisting essentially of softwood chemical pulp, the method comprising the steps of: preparing softwood chemical pulp to obtain a consistency of from 5% to 50% O.D.; passing the 5% to 50% O.D. softwood chemical pulp through a plug screw feeder having a nominal compression ratio of at least 2.0 to 1 to wring, dewater and compact the pulp and to permanently twist and kink individual fibers to a degree that is substantially irreversible when they are subsequently subjected to papermaking process steps, and thus producing a treated softwood chemical pulp; restricting the flow of the treated softwood chemical pulp exiting from the plug screw feeder; the treated softwood chemical pulp having, (a) increased freeness; (b) reduced tensile strength; (c) increased bulk; (d) reduced tearing resistance; and (e) greater softness, than the same softwood chemical pulp which has not been passed through a plug screw feeder to twist and kink individual fibers; and feeding the treated softwood chemical pulp into a headbox of a papermaking machine to produce a paper product having greater softness than a paper product made from the same softwood chemical pulp that has not been so mechanically treated.
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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) | 1993-12-10 | 1994-06-11 | 1994-12-11 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1997-12-10 | 1998-06-11 | 1998-12-11 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2001-12-10 | 2002-06-11 | 2002-12-11 | $7700.00 | Window Closed / Lapsed |