US4155888A
Expired / Lapsed
US
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Water-absorbent starches
Assignee: Staley Continental Inc
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Filing: 1978-04-17
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Granted: 1979-05-22
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Expires: 1998-04-17
Abstract
Abstract {PG,1 Water-absorbent starch products may be prepared by simultaneously drying and polymerizing an aqueous media containing starch, ethylenic unsaturated monomer and free-radical initiator. Without necessitating further refining or chemical modification, effective water-absorbent, drum-dried products essentially free from water-soluble salts and free-radical initiator contaminants and containing a high level of functional water-attractant groups may be directly manufactured. If desired, the water-absorbent starch products may be further refined to increase the water-absorbent properties of the starch polymer.
Inventors
- 👤 Robert A. Mooth
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 16:06
CPC Classifications
C; C08; C08F; C08F251/00; A; A61; A61L; A61L15/00; A61L15/16; A61L15/42; A61L15/60
Claims Analysis
Total Claims: 15
Claim 1
Independent Claim
66 words
A method for preparing a water-absorbent starch product, said method comprising: a. forming an aqueous dispersion comprising starch, water, free-radical initiator and ethylenically unsaturated monomer wherein the monomer consists essentially of monomer having a boiling point of at least 100° C.; and b. simultaneously polymerizing and drying the aqueous dispersion at a temperature above 100° C. to provide a dry, water-absorbent starch product or precursor thereof.
Claim 2
Independent Claim
66 words
A method for preparing a water-absorbent starch product, said method comprising: a. forming an aqueous dispersion comprising starch, water, free-radical initiator and ethylenically unsaturated monomer wherein the monomer consists essentially of monomer having a boiling point of at least 100° C.; and b. simultaneously polymerizing and drying the aqueous dispersion at a temperature above 100° C. to provide a dry, water-absorbent starch product or precursor thereof.
Claim 3
Dependent Claim
25 words
The method according to claim 1 wherein at least a major weight portion of the polymerized monomer comprises the salt of alpha, beta-ethylenically unsaturated acid.
Claim 4
Dependent Claim
58 words
The method according to claim 1 wherein the starch to monomer molar ratios ranges from about 2:3 to about 1:5 at least 80% of the monomer weight comprises an alkali metal salt of an alpha, beta-ethylenically unsaturated acid, and the dispersion is simultaneously dried and polymerized at a temperature ranging from about 120° C. to about 140° C.
Claim 5
Dependent Claim
14 words
The method according to claim 2 wherein the free-radical initiator comprises a persulfate initiator.
Claim 6
Dependent Claim
51 words
The method according to claim 1 wherein the aqueous dispersion contains from about 30% to about 70% by weight water, the simultaneous polymerization and drying of the aqueous dispersion is effectuated upon the surface of at least one roller at a temperature ranging from about 100° C. to about 200° C.
Claim 7
Dependent Claim
52 words
The method according to claim 5 wherein the aqueous dispersion comprises from about 45% to about 60% by weight water, the monomer comprises at least 95% by weight of a water-soluble metal salt of an ethylenically unsaturated acid monomer and the starch to monomer ratio ranges from about 2:1 to about 1:10.
Claim 8
Dependent Claim
41 words
The method according to claim 6 wherein the free-radical initiator consists essentially of a persulfate initiator and the monomer is the alkali or alkaline earth salt of at least one member selected from the group consisting of acrylic and methacrylic acid.
Claim 9
Dependent Claim
35 words
The method according to claim 7 wherein the aqueous dispersion is simultaneously dried and polymerized upon the surface of at least one roller at a temperature ranging from about 110° C. to about 150° C.
Claim 10
Dependent Claim
28 words
The method according to claim 7 wherein the polymerized monomer consists essentially of at least one monomer selected from the group consisting of potassium acrylate and potassium methacrylate.
Claim 11
Dependent Claim
22 words
The method according to claim 9 wherein the simultaneous polymerization and drying of the aqueous dispersion is effectuated by a drum-drying process.
Claim 12
Dependent Claim
13 words
The water-absorbent starch product prepared in accordance with the method of claim 1.
Claim 13
Dependent Claim
12 words
The water-absorbent product prepared in accordance with the method of claim 3.
Claim 14
Dependent Claim
13 words
The water-absorbent starch product prepared in accordance with the method of claim 6.
Claim 15
Dependent Claim
13 words
The water-absorbent starch product prepared in accordance with the method of claim 10.
References Cited (Backward Citations)
US2668156A
Cited
US3976552A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1982-05-21 | 1982-11-20 | 1983-05-22 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1986-05-21 | 1986-11-20 | 1987-05-22 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1990-05-21 | 1990-11-20 | 1991-05-22 | $7700.00 | Window Closed / Lapsed |