US5550189A
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Modified polysaccharides having improved absorbent properties and process for the preparation thereof
Assignee: Kimberly Clark Worldwide Inc
•
Filing: 1993-10-29
•
Granted: 1996-08-27
•
Expires: 2013-10-29
Abstract
Abstract Disclosed is a method for producing a water-swellable, generally water-insoluble modified polysaccharide having improved age-stable absorption properties. The method involves forming a mixture of a modified polysaccharide, water, and, optionally, a crosslinking agent, recovering the modified polysaccharide from the mixture and, optionally, heat-treating said recovered modified polysaccharide.
Inventors
- 👤 Jian Qin
- 👤 James R. Gross
- 👤 William J. Mui
- 👤 Xin Ning
- 👤 Wen Z. Schroeder
- 👤 Tong Sun
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 13:30
CPC Classifications
C; C08; C08L; C08L1/00; C08L1/08; C08L1/26; C08L1/28; C08L1/286; A; A61; A61L; A61L15/00; A61L15/16; A61L15/22; A61L15/28; A61L15/42; A61L15/60; C08B; C08B11/00; C08B11/02; C08B11/04; C08B11/10; C08B11/12; C08B15/00; C08B15/005; C08B37/00; C08B37/0006; C08B37/0024; C08B37/0027; C08B37/003; C08L5/00; C08L5/08
Claims Analysis
Total Claims: 74
Claim 1
Independent Claim
134 words
A method for producing a water-swellable, water-insoluble carboxyalkyl polysaccharide, the method comprising the following steps: forming a homogeneous mixture comprising a water-soluble carboxyalkyl polysaccharide, water, and a crosslinking agent, wherein the water-soluble carboxyalkyl polysaccharide dissolves into the water; recovering said carboxyalkyl polysaccharide and said crosslinking agent from said mixture; and heat-treating said recovered carboxyalkyl polysaccharide and said crosslinking agent at a temperature above about 50° C. for a time effective to crosslink said carboxyalkyl polysaccharide to render said carboxyalkyl polysaccharide water swellable and water insoluble, wherein the water-swellable, water-insoluble carboxyalkyl polysaccharide exhibits an initial Absorbency Under Load value of at least 17 and retains at least about 50 percent of the initial Absorbency Under Load value after aging for about 60 days at about 24° C. and at least about 30 percent relative humidity.
Claim 2
Independent Claim
134 words
A method for producing a water-swellable, water-insoluble carboxyalkyl polysaccharide, the method comprising the following steps: forming a homogeneous mixture comprising a water-soluble carboxyalkyl polysaccharide, water, and a crosslinking agent, wherein the water-soluble carboxyalkyl polysaccharide dissolves into the water; recovering said carboxyalkyl polysaccharide and said crosslinking agent from said mixture; and heat-treating said recovered carboxyalkyl polysaccharide and said crosslinking agent at a temperature above about 50° C. for a time effective to crosslink said carboxyalkyl polysaccharide to render said carboxyalkyl polysaccharide water swellable and water insoluble, wherein the water-swellable, water-insoluble carboxyalkyl polysaccharide exhibits an initial Absorbency Under Load value of at least 17 and retains at least about 50 percent of the initial Absorbency Under Load value after aging for about 60 days at about 24° C. and at least about 30 percent relative humidity.
Claim 3
Dependent Claim
33 words
The method according to claim 1 wherein the carboxyalkyl polysaccharide is prepared from a polysaccharide selected from the group consisting of cellulose, starch, guar, carrageenan, agar, gellan gum, chitin, chitosan, and mixtures thereof.
Claim 4
Dependent Claim
14 words
The method according to claim 1 wherein the carboxyalkyl polysaccharide is a carboxyalkyl cellulose.
Claim 5
Dependent Claim
14 words
The method according to claim 1 wherein the carboxyalkyl polysaccharide is a carboxymethyl polysaccharide.
Claim 6
Dependent Claim
13 words
The method according to claim 4 wherein the carboxymethyl polysaccharide is carboxymethyl cellulose.
Claim 7
Dependent Claim
24 words
The method according to claim 1 wherein the water-swellable, water-insoluble carboxyalkyl polysaccharide exhibits an initial Absorbency Under Load value of at least about 20.
Claim 8
Dependent Claim
40 words
The method according to claim 1 wherein said recovered carboxyalkyl polysaccharide and crosslinking agent are heat-treated at a temperature of from about 100° C. to about 200° C. for a time of from about 1 minute to about 600 minutes.
Claim 9
Dependent Claim
28 words
The method according to claim 1 wherein said mixture, comprising said water-soluble carboxyalkyl polysaccharide, water, and a crosslinking agent, has a pH between about 4 to about 9.
Claim 10
Dependent Claim
35 words
The method according to claim 1 wherein the heat-treated carboxyalkyl polysaccharide has an initial Absorbency Under Load value at least about 10 percent greater than an otherwise identical carboxyalkyl polysaccharide prepared without a crosslinking agent.
Claim 11
Dependent Claim
35 words
The method according to claim 9 wherein the heat-treated carboxyalkyl polysaccharide has an initial Absorbency Under Load value at least about 20 percent greater than an otherwise identical carboxyalkyl polysaccharide prepared without a crosslinking agent.
Claim 12
Dependent Claim
43 words
The method according to claim 1 wherein the water-swellable, water-insoluble carboxyalkyl polysaccharide retains at least about 70 percent of the initial Absorbency Under Load value after aging for about 60 days at about 24° C. and at least about 30 percent relative humidity.
Claim 13
Dependent Claim
42 words
The method according to claim 1 wherein the water-swellable, water-insoluble carboxyalkyl polysaccharide retains at least about 50 percent of the initial Absorbency Under Load value after aging for about 60 days at about 24° C. and at about 100 percent relative humidity.
Claim 14
Dependent Claim
19 words
The method according to claim 1 wherein said carboxyalkyl polysaccharide and said crosslinking agent are recovered by evaporative drying.
Claim 15
Dependent Claim
18 words
The method according to claim 1 wherein said carboxyalkyl polysaccharide and said crosslinking agent are recovered by precipitation.
Claim 16
Dependent Claim
50 words
The method according to claim 1 wherein the crosslinking agent is selected from the group consisting of an organic compound comprising at least two functional groups capable of reacting with a carboxyl, amino, or hydroxyl group of a carboxyalkyl polysaccharide or a metal ion with more than two positive charges.
Claim 17
Dependent Claim
24 words
The method according to claim 15 wherein said crosslinking agent is selected from the group consisting of diamines, polyamines, diols, polyols and mixtures thereof.
Claim 18
Dependent Claim
36 words
The method according to claim 6 wherein the crosslinking agent is selected from the group consisting of chitosan glutamate, type A gelatin, diethylenetriamine, ethylene glycol, butylene glycol, polyvinyl alcohol, hyaluronic acid, polyethylene imine, and mixtures thereof.
Claim 19
Dependent Claim
25 words
The method according to claim 15 wherein said crosslinking agent is selected from the group consisting of chloroacetic acid and sodium chloroacetate and mixtures thereof.
Claim 20
Dependent Claim
39 words
The method according to claim 15 wherein said crosslinking agent comprises a metal ion selected from the group consisting of Al 3+ , Fe 3+ , Ce 3+ , Ti 4+ , Zr 4+ , and Ce 4+ .
Claim 21
Dependent Claim
53 words
The method according to claim 19 wherein said crosslinking agent is selected from the group consisting of AlCl 3 , FeCl 3 , Ce 2 (SO 4 ) 3 , Zr(NH 4 ) 4 (CO 3 ) 4 , Ce(NH 4 ) 4 (SO 4 ) 4 ·2H 2 O, and mixtures thereof.
Claim 22
Dependent Claim
42 words
The method according to claim 1 wherein the water-swellable, water-insoluble carboxymethyl cellulose retains at least about 50 percent of the initial Absorbency Under Load value after aging for about 60 days at about 24° C. and at about 100 percent relative humidity.
Claim 23
Independent Claim
169 words
A method for producing a water-swellable, water-insoluble carboxymethyl cellulose, the method comprising the following steps: forming a homogeneous mixture comprising a water-soluble carboxymethyl cellulose, water, and a crosslinking agent selected from the group consisting of organic compounds comprising at least two functional groups capable of reacting with a carboxyl or hydroxyl group of a carboxyalkyl polysaccharide and a metal ion having more than 2 positive charges, wherein the water-soluble carboxyalkyl polysaccharide dissolves into the water; recovering said carboxymethyl cellulose and said crosslinking agent from said mixture; and heat-treating said recovered carboxymethyl cellulose and crosslinking agent at a temperature above about 100° C. for a time effective to crosslink said carboxymethyl cellulose to render said carboxymethyl cellulose water swellable and water insoluble wherein said heat-treated carboxymethyl cellulose has an initial Absorbency Under Load value of at least 17 and retains at least about 50 percent of the initial Absorbency Under Load value after aging for about 60 days at about 24° C. and at least about 30 percent relative humidity.
Claim 24
Independent Claim
169 words
A method for producing a water-swellable, water-insoluble carboxymethyl cellulose, the method comprising the following steps: forming a homogeneous mixture comprising a water-soluble carboxymethyl cellulose, water, and a crosslinking agent selected from the group consisting of organic compounds comprising at least two functional groups capable of reacting with a carboxyl or hydroxyl group of a carboxyalkyl polysaccharide and a metal ion having more than 2 positive charges, wherein the water-soluble carboxyalkyl polysaccharide dissolves into the water; recovering said carboxymethyl cellulose and said crosslinking agent from said mixture; and heat-treating said recovered carboxymethyl cellulose and crosslinking agent at a temperature above about 100° C. for a time effective to crosslink said carboxymethyl cellulose to render said carboxymethyl cellulose water swellable and water insoluble wherein said heat-treated carboxymethyl cellulose has an initial Absorbency Under Load value of at least 17 and retains at least about 50 percent of the initial Absorbency Under Load value after aging for about 60 days at about 24° C. and at least about 30 percent relative humidity.
Claim 25
Dependent Claim
73 words
The method according to claim 22 wherein said crosslinking agent is selected from the group consisting of chitosan glutamate, type A gelatin, diethylenetriamine, ethylene glycol, butylene glycol, polyvinyl alcohol, hyaluronic acid, polyethylene imine, chloroacetic acid, sodium chloroacetate, AlCl 3 , FeCl 3 , Ce 2 (SO 4 ) 3 , Zr(NH 4 ) 4 (CO 3 ) 4 , Ce(NH 4 ) 4 (SO 4 ) 4 ·2H 2 O, and mixtures thereof.
Claim 26
Dependent Claim
40 words
The method according to claim 22 wherein said carboxymethyl cellulose and said crosslinking agent are heat-treated at a temperature of from about 100° C. to about 200° C. for a time of from about 1 minute to about 600 minutes.
Claim 27
Dependent Claim
19 words
The method according to claim 22 wherein said carboxymethyl cellulose and said crosslinking agent are recovered by evaporative drying.
Claim 28
Dependent Claim
43 words
The method according to claim 22 wherein the water-swellable, water-insoluble carboxymethyl cellulose retains at least about 70 percent of the initial Absorbency Under Load value after aging for about 60 days at about 24° C. and at least about 30 percent relative humidity.
Claim 29
Independent Claim
140 words
A method for producing a water-swellable, water-insoluble carboxyalkyl polysaccharide, the method comprising the following steps: forming a homogeneous mixture comprising a water-soluble carboxyalkyl polysaccharide and water, wherein the water-soluble carboxyalkyl polysaccharide dissolves into the water; recovering said carboxyalkyl polysaccharide from said mixture; and heat-treating said recovered carboxyalkyl polysaccharide at a temperature between about 200° C. and about 250° C. for an amount of time between about 50 to about 90 seconds, wherein said heat-treating is effective to crosslink said carboxyalkyl polysaccharide to render said carboxyalkyl polysaccharide water swellable and water insoluble, wherein the water-swellable, water-insoluble carboxyalkyl polysaccharide exhibits an initial Absorbency Under Load value of at least 17 and retains at least about 50 percent of the initial Absorbency Under Load value after aging for about 60 days at about 24° C. and at least about 30 percent relative humidity.
Claim 30
Independent Claim
140 words
A method for producing a water-swellable, water-insoluble carboxyalkyl polysaccharide, the method comprising the following steps: forming a homogeneous mixture comprising a water-soluble carboxyalkyl polysaccharide and water, wherein the water-soluble carboxyalkyl polysaccharide dissolves into the water; recovering said carboxyalkyl polysaccharide from said mixture; and heat-treating said recovered carboxyalkyl polysaccharide at a temperature between about 200° C. and about 250° C. for an amount of time between about 50 to about 90 seconds, wherein said heat-treating is effective to crosslink said carboxyalkyl polysaccharide to render said carboxyalkyl polysaccharide water swellable and water insoluble, wherein the water-swellable, water-insoluble carboxyalkyl polysaccharide exhibits an initial Absorbency Under Load value of at least 17 and retains at least about 50 percent of the initial Absorbency Under Load value after aging for about 60 days at about 24° C. and at least about 30 percent relative humidity.
Claim 31
Dependent Claim
33 words
The method according to claim 27 wherein the carboxyalkyl polysaccharide is prepared from a polysaccharide selected from the group consisting of cellulose, starch, guar, carrageenan, agar, gellan gum, chitin, chitosan, and mixtures thereof.
Claim 32
Dependent Claim
14 words
The method according to claim 28 wherein the carboxyalkyl polysaccharide is a carboxymethyl polysaccharide.
Claim 33
Dependent Claim
13 words
The method according to claim 29 wherein the carboxymethyl polysaccharide is carboxymethyl cellulose.
Claim 34
Dependent Claim
14 words
The method according to claim 27 wherein the carboxyalkyl polysaccharide is a carboxyalkyl cellulose.
Claim 35
Dependent Claim
15 words
The method according to claim 27 wherein said carboxyalkyl polysaccharide is recovered by evaporative drying.
Claim 36
Dependent Claim
25 words
The method according to claim 27 wherein said mixture, comprising said water-soluble carboxyalkyl polysaccharide and water has a pH between about 5 to about 9.
Claim 37
Dependent Claim
24 words
The method according to claim 27 wherein the water-swellable, water-insoluble carboxyalkyl polysaccharide exhibits an initial Absorbency Under Load value of at least about 20.
Claim 38
Dependent Claim
43 words
The method according to claim 27 wherein the water-swellable, water-insoluble carboxyalkyl polysaccharide retains at least about 70 percent of the initial Absorbency Under Load value after aging for about 60 days at about 24° C. and at least about 30 percent relative humidity.
Claim 39
Dependent Claim
42 words
The method according to claim 27 wherein the water-swellable, water-insoluble carboxyalkyl polysaccharide retains at least about 50 percent of the initial Absorbency Under Load value after aging for about 60 days at about 24° C. and at about 100 percent relative humidity.
Claim 40
Independent Claim
114 words
A method for producing a water-swellable, water-insoluble carboxyalkyl polysaccharide, the method comprising the following steps: forming a homogeneous mixture comprising a water-soluble carboxyalkyl polysaccharide and water, wherein the water-soluble carboxyalkyl polysaccharide dissolves into the water; adding to the homogeneous mixture a solution comprising a crosslinking agent, comprising an aluminum ion, dissolved in water; and recovering said carboxyalkyl polysaccharide and said crosslinking agent from said mixture, wherein the water-swellable, water-insoluble carboxyalkyl polysaccharide exhibits an initial Absorbency Under Load value of at least 8 and retains at least about 50 percent of the initial Absorbency Under Load value after aging for about 60 days at about 24° C. and at least about 30 percent relative humidity.
Claim 41
Independent Claim
114 words
A method for producing a water-swellable, water-insoluble carboxyalkyl polysaccharide, the method comprising the following steps: forming a homogeneous mixture comprising a water-soluble carboxyalkyl polysaccharide and water, wherein the water-soluble carboxyalkyl polysaccharide dissolves into the water; adding to the homogeneous mixture a solution comprising a crosslinking agent, comprising an aluminum ion, dissolved in water; and recovering said carboxyalkyl polysaccharide and said crosslinking agent from said mixture, wherein the water-swellable, water-insoluble carboxyalkyl polysaccharide exhibits an initial Absorbency Under Load value of at least 8 and retains at least about 50 percent of the initial Absorbency Under Load value after aging for about 60 days at about 24° C. and at least about 30 percent relative humidity.
Claim 42
Dependent Claim
33 words
The method according to claim 37 wherein the carboxyalkyl polysaccharide is prepared from a polysaccharide selected from the group consisting of cellulose, starch, guar, carrageenan, agar, gellan gum, chitin, chitosan, and mixtures thereof.
Claim 43
Dependent Claim
14 words
The method according to claim 37 wherein the carboxyalkyl polysaccharide is a carboxyalkyl cellulose.
Claim 44
Dependent Claim
14 words
The method according to claim 37 wherein the carboxyalkyl polysaccharide is a carboxymethyl polysaccharide.
Claim 45
Dependent Claim
13 words
The method according to claim 40 wherein the carboxymethyl polysaccharide is carboxymethyl cellulose.
Claim 46
Dependent Claim
19 words
The method according to claim 37 wherein said carboxyalkyl polysaccharide and said crosslinking agent are recovered by evaporative drying.
Claim 47
Dependent Claim
24 words
The method according to claim 37 wherein the water-swellable, water-insoluble carboxyalkyl polysaccharide exhibits an initial Absorbency Under Load value of at least about 20.
Claim 48
Dependent Claim
43 words
The method according to claim 37 wherein the water-swellable, water-insoluble carboxyalkyl polysaccharide retains at least about 70 percent of the initial Absorbency Under Load value after aging for about 60 days at about 24° C. and at least about 30 percent relative humidity.
Claim 49
Dependent Claim
42 words
The method according to claim 37 wherein the water-swellable, water-insoluble carboxyalkyl polysaccharide retains at least about 50 percent of the initial Absorbency Under Load value after aging for about 60 days at about 24° C. and at about 100 percent relative humidity.
Claim 50
Independent Claim
197 words
A method for producing a water-swellable, water-insoluble carboxyalkyl polysaccharide comprising: a. preparing a reaction dispersion comprising a solvent and a polysaccharide comprising an original crystalline structure; b. adding a carboxyalkylating reagent to the reaction dispersion at conditions effective to allow the carboxyalkylating reagent to react with the polysaccharide to prepare a water-insoluble, water-dispersible carboxyalkyl polysaccharide, wherein the carboxyalkyl polysaccharide comprises an amount of the original crystalline structure of the polysaccharide and a non-crystalline structure; c. recovering the water-insoluble, water-dispersible carboxyalkyl polysaccharide from the reaction dispersion; d. preparing a mixture comprising the recovered water-insoluble, water-dispersible carboxyalkyl polysaccharide and water, wherein the carboxyalkyl polysaccharide is dispersed in the water and the non-crystalline structure of the carboxyalkyl polysaccharide dissolves into the water; and e. recovering the carboxyalkyl polysaccharide from the mixture, wherein the carboxyalkyl polysaccharide comprises an amount of the original crystalline structure of the polysaccharide to be effective to result in a water-swellable, water-insoluble carboxyalkyl polysaccharide exhibiting an initial Absorbency Under Load value of at least 17 and retaining at least about 50 percent of the initial Absorbency Under Load value after aging for about 60 days at about 24° C. and at least about 30 percent relative humidity.
Claim 51
Independent Claim
197 words
A method for producing a water-swellable, water-insoluble carboxyalkyl polysaccharide comprising: a. preparing a reaction dispersion comprising a solvent and a polysaccharide comprising an original crystalline structure; b. adding a carboxyalkylating reagent to the reaction dispersion at conditions effective to allow the carboxyalkylating reagent to react with the polysaccharide to prepare a water-insoluble, water-dispersible carboxyalkyl polysaccharide, wherein the carboxyalkyl polysaccharide comprises an amount of the original crystalline structure of the polysaccharide and a non-crystalline structure; c. recovering the water-insoluble, water-dispersible carboxyalkyl polysaccharide from the reaction dispersion; d. preparing a mixture comprising the recovered water-insoluble, water-dispersible carboxyalkyl polysaccharide and water, wherein the carboxyalkyl polysaccharide is dispersed in the water and the non-crystalline structure of the carboxyalkyl polysaccharide dissolves into the water; and e. recovering the carboxyalkyl polysaccharide from the mixture, wherein the carboxyalkyl polysaccharide comprises an amount of the original crystalline structure of the polysaccharide to be effective to result in a water-swellable, water-insoluble carboxyalkyl polysaccharide exhibiting an initial Absorbency Under Load value of at least 17 and retaining at least about 50 percent of the initial Absorbency Under Load value after aging for about 60 days at about 24° C. and at least about 30 percent relative humidity.
Claim 52
Dependent Claim
26 words
The method according to claim 46 wherein the carboxyalkyl polysaccharide is prepared from a polysaccharide selected from the group consisting of cellulose, chitin, and mixtures thereof.
Claim 53
Dependent Claim
14 words
The method according to claim 46 wherein the carboxyalkyl polysaccharide is a carboxyalkyl cellulose.
Claim 54
Dependent Claim
14 words
The method according to claim 46 wherein the carboxyalkyl polysaccharide is a carboxymethyl polysaccharide.
Claim 55
Dependent Claim
13 words
The method according to claim 49 wherein the carboxymethyl polysaccharide is carboxymethyl cellulose.
Claim 56
Dependent Claim
18 words
The method according to claim 46 wherein said carboxyalkyl polysaccharide is recovered from the mixture by evaporative drying.
Claim 57
Dependent Claim
24 words
The method according to claim 46 wherein the water-swellable, water-insoluble carboxyalkyl polysaccharide exhibits an initial Absorbency Under Load value of at least about 20.
Claim 58
Dependent Claim
43 words
The method according to claim 46 wherein the water-swellable, water-insoluble carboxyalkyl polysaccharide retains at least about 70 percent of the initial Absorbency Under Load value after aging for about 60 days at about 24° C. and at least about 30 percent relative humidity.
Claim 59
Dependent Claim
42 words
The method according to claim 46 wherein the water-swellable, water-insoluble carboxyalkyl polysaccharide retains at least about 50 percent of the initial Absorbency Under Load value after aging for about 60 days at about 24° C. and at about 100 percent relative humidity.
Claim 60
Dependent Claim
19 words
The method according to claim 46 wherein potassium hydroxide is used as an alkali to prepare the carboxyalkyl polysaccharide.
Claim 61
Dependent Claim
26 words
The method according to claim 46 wherein a less than stoichiometric ratio of an alkali to the carboxyalkylating reagent is used to prepare the carboxyalkyl polysaccharide.
Claim 62
Dependent Claim
23 words
The method according to claim 56 wherein the ratio of the alkali to the carboxyalkylating reagent is less than about 2 to 1.
Claim 63
Dependent Claim
24 words
The method according to claim 46 wherein a reactant molar ratio of the carboxyalkylating reagent to the polysaccharide is less than 1 to 1.
Claim 64
Dependent Claim
18 words
The method according to claim 56 wherein the carboxyalkylating reagent is chloroacetic acid and the polysaccharide is cellulose.
Claim 65
Independent Claim
115 words
A method for producing a water-swellable, water-insoluble carboxyalkyl polysaccharide comprising: a. preparing a mixture comprising a water-insoluble, water-dispersible carboxyalkyl polysaccharide, wherein the carboxyalkyl polysaccharide comprises a crystalline structure and a non-crystalline structure, and water, wherein the carboxyalkyl polysaccharide is dispersed in the water and the non-crystalline structure of the carboxyalkyl polysaccharide dissolves into the water, and b. recovering the carboxyalkyl polysaccharide from the mixture to result in a water-swellable, water-insoluble carboxyalkyl polysaccharide exhibiting an initial Absorbency Under Load value of at least 17 and retaining at least about 50 percent of the initial Absorbency Under Load value after aging for about 60 days at about 24° C. and at least about 30 percent relative humidity.
Claim 66
Independent Claim
115 words
A method for producing a water-swellable, water-insoluble carboxyalkyl polysaccharide comprising: a. preparing a mixture comprising a water-insoluble, water-dispersible carboxyalkyl polysaccharide, wherein the carboxyalkyl polysaccharide comprises a crystalline structure and a non-crystalline structure, and water, wherein the carboxyalkyl polysaccharide is dispersed in the water and the non-crystalline structure of the carboxyalkyl polysaccharide dissolves into the water, and b. recovering the carboxyalkyl polysaccharide from the mixture to result in a water-swellable, water-insoluble carboxyalkyl polysaccharide exhibiting an initial Absorbency Under Load value of at least 17 and retaining at least about 50 percent of the initial Absorbency Under Load value after aging for about 60 days at about 24° C. and at least about 30 percent relative humidity.
Claim 67
Dependent Claim
26 words
The method according to claim 60 wherein the carboxyalkyl polysaccharide is prepared from a polysaccharide selected from the group consisting of cellulose, chitin, and mixtures thereof.
Claim 68
Dependent Claim
14 words
The method according to claim 60 wherein the carboxyalkyl polysaccharide is a carboxyalkyl cellulose.
Claim 69
Dependent Claim
14 words
The method according to claim 60 wherein the carboxyalkyl polysaccharide is a carboxymethyl polysaccharide.
Claim 70
Dependent Claim
13 words
The method according to claim 63 wherein the carboxymethyl polysaccharide is carboxymethyl cellulose.
Claim 71
Dependent Claim
18 words
The method according to claim 60 wherein said carboxyalkyl polysaccharide is recovered from the mixture by evaporative drying.
Claim 72
Dependent Claim
24 words
The method according to claim 60 wherein the water-swellable, water-insoluble carboxyalkyl polysaccharide exhibits an initial Absorbency Under Load value of at least about 20.
Claim 73
Dependent Claim
43 words
The method according to claim 60 wherein the water-swellable, water-insoluble carboxyalkyl polysaccharide retains at least about 70 percent of the initial Absorbency Under Load value after aging for about 60 days at about 24° C. and at least about 30 percent relative humidity.
Claim 74
Dependent Claim
42 words
The method according to claim 60 wherein the water-swellable, water-insoluble carboxyalkyl polysaccharide retains at least about 50 percent of the initial Absorbency Under Load value after aging for about 60 days at about 24° C. and at about 100 percent relative humidity.
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| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
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| 3.5 Years (Year 4) | 1999-08-27 | 2000-02-26 | 2000-08-27 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2003-08-27 | 2004-02-26 | 2004-08-27 | $3760.00 | Window Closed / Lapsed |
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