Patent EP0440472B1 successfully refreshed from Google Patents.
EP0440472B1
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High bulking resilient fibers through cross linking of wood pulp fibers with polycarboxylic acids
Assignee: Fort James Corp
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Filing: 1991-01-31
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Granted: 1995-08-16
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Expires: 2011-01-31
Abstract
Abstract The invention relates to resilient bulking fibers prepared by crosslinking wood pulp fibers with polycarboxylic acids.
Inventors
- 👤 Bruce Jerome Kokko
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-24 20:54
CPC Classifications
D; D21; D21C; D21C9/00; D21C9/001; D21C9/002; D21C9/005; D21H; D21H11/00; D21H11/16; D21H11/20
Claims Analysis
Total Claims: 33
Claim 1
Independent Claim
51 words
Individualized crosslinked wood pulp cellulosic fibers having intra-fiber chemical bonds characterised in that the intra-fiber crosslink bonds derive from a polycarboxylic acid, and the degree of crosslinking is at least that sufficient to induce in said individualized fibers at least one of the following, namely twisting, curling and resilient bulking tendency.
Claim 2
Dependent Claim
33 words
Individualized wood pulp cellulosic fibers as claimed in claim 1 crosslinked by from 1 mole % to 25 mole %, calculated on a cellulosic anhydroglucose molar basis, of a polycarboxylic acid crosslinking agent.
Claim 3
Dependent Claim
29 words
Individualized crosslinked wood pulp cellulosic fibers as claimed in claim 1 or claim 2 in which the polycarboxylic acid crosslinking agent is selected from citric acid and butanetetracarboxylic acid.
Claim 4
Dependent Claim
22 words
A resilient fibrous bulking pulp comprising individualized crosslinked wood pulp cellulosic fibers as claimed in any one of claims 1 to 3.
Claim 5
Independent Claim
62 words
A method for preparing resilient bulking fibers by: (a) contacting wood pulp cellulosic fibers with a crosslinking agent; (b) individualizing the cellulosic fibers; and (c) curing the individualized cellulosic fibers to form intra-fiber cross-link bonds derived from said crosslinking agent between cellulose molecules within individual fibers of the cellulosic fibers, characterised in that a polycarboxylic acid is employed as the crosslinking agent.
Claim 6
Dependent Claim
23 words
A method as claimed in claim 5 wherein step (a) comprises mixing wood pulp cellulosic fibers with an aqueous solution of polycarboxylic acid.
Claim 7
Dependent Claim
16 words
A method as claimed in claim 6 wherein step (b) comprises dewatering and drying the fibers.
Claim 8
Dependent Claim
19 words
A method as claimed in claim 7 wherein the dewatering comprises pressing the cellulosic fibers through a screw press.
Claim 9
Dependent Claim
22 words
A method as claimed in claim 7 or claim 8 wherein the fibers are dewatered to a consistency of at least 30%.
Claim 10
Independent Claim
18 words
A method as claimed in any one of claims 7 to 9 wherein the drying comprises fluff drying.
Claim 11
Independent Claim
16 words
A method as claimed in claims 10 wherein the fluff drying is effected with hot gases.
Claim 12
Independent Claim
20 words
A method as claimed in any one of claims 7 to 11 wherein the drying is effected with superheated steam.
Claim 13
Independent Claim
21 words
A method as claimed in any one of claims 7 to 12 wherein the drying is effected in a reducing atmosphere.
Claim 14
Independent Claim
24 words
A method as claimed in any one of claims 7 to 9 wherein the drying step comprises azeotropically drying the fibers in a solvent.
Claim 15
Independent Claim
30 words
A method as claimed in any one of claims 7 to 14 wherein the drying step is performed at a temperature lower than that used for curing in step (c).
Claim 16
Independent Claim
19 words
The method of any one of claims 5 to 15 wherein the curing is effected in a reducing atmosphere.
Claim 17
Independent Claim
22 words
The method of any one of claims 6 to 16 wherein said aqueous solution is 3-10% aqueous solution of a polycarboxylic acid.
Claim 18
Independent Claim
18 words
The method of any one of claims 6 to 17 wherein the aqueous solution includes a caustic agent.
Claim 19
Independent Claim
20 words
The method of any one of claims 6 to 17 wherein said aqueous solution comprises citric acid and a coreactant/accelerator.
Claim 20
Dependent Claim
17 words
The method of claim 19 wherein said coreactant/accelerator is selected from phosphates, phosphites, hypophosphites, pyrophosphates and metaphosphates.
Claim 21
Dependent Claim
11 words
The method of claim 20 wherein the coreactant/accelerator is monosodium phosphate.
Claim 22
Independent Claim
22 words
The method of any one of claims 5 to 21 wherein said polycarboxylic acid is selected from citric acid and butanetetracarboxylic acid.
Claim 23
Independent Claim
42 words
The method of any one of claims 5 to 22 wherein the curing step comprises heating the fibers at a temperature in the range of from 150 to 180°C for a time period in the range of from 0.5 to 10 minutes.
Claim 24
Independent Claim
32 words
The method of any one of claims 5 to 23 wherein said wood pulp fibers are selected from chemical thermal mechanical pulps, Southern and Northern softwood bleached Waft pulps, and secondary fibers.
Claim 25
Independent Claim
18 words
The method of any one of claims 5 to 24 wherein said wood pulp fibers are never-dried fibers.
Claim 26
Dependent Claim
54 words
An improved resilient bulking and absorbent paper product comprising crosslinked wood pulp cellulose fibers to provide improved bulking and absorbent properties, characterised in that the crosslinked fibers are as claimed in any one of claims 1 to 3 or are obtained by a method as claimed in any one of claims 5 to 25.
Claim 27
Dependent Claim
21 words
A paper product as claimed in claim 26 wherein said crosslinked wood pulp cellulose fibers contain both intra-fiber and interfiber bonds.
Claim 28
Dependent Claim
12 words
The paper product of claim 26 or 27 further comprising non-crosslinked fibers.
Claim 29
Dependent Claim
20 words
The paper product of claim 28 wherein said non-crosslinked fibers comprise the majority of said product, on a weight basis.
Claim 30
Dependent Claim
16 words
The paper product of claim 28 or claim 29 wherein said non-crosslinked fibers are wood fibers.
Claim 31
Dependent Claim
40 words
The paper product of claim 30 wherein said wood fibers are selected from predried or never dried Scandinavian bleached spruce kraft, Southern pine bleached kraft, secondary fibers, Southern softwood kraft, Northern softwood kraft, and never dried Northern softwood bleached kraft.
Claim 32
Dependent Claim
29 words
The paper product of any one of claims 26 to 31 wherein said paper product is selected from handsheets, towels, tissues, filters, paperboard, diapers, sanitary napkins, and hospital dressings.
Claim 33
Dependent Claim
27 words
The use of polycarboxylic acid as the cross-linking agent to induce twisting and curling in individualized wood pulp cellulosic fibers by the formation of intra-fiber crosslink bonds.
References Cited (Backward Citations)
No citation records indexed.
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