US4483950A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Modified starches as extenders for absorbent polymers
Assignee: United States Department of Agriculture
•
Filing: 1982-12-10
•
Granted: 1984-11-20
•
Expires: 2002-12-10
Abstract
Abstract Starch-based superabsorbents are extended by blending with highly modified, low molecular weight starches. The dextrinized starches synergistically interact with the superabsorbents thereby permitting dilution without a commensurate reduction in the water absorbency. While the principal utility of the blends is the absorption of aqueous fluids, when hydrated they yield soft, smooth gels useful as high-quality thickening agents.
Inventors
- 👤 George F. Fanta
- 👤 William M. Doane
- 👤 Edward I. Stout
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 12:47
CPC Classifications
A; A61; A61L; A61L15/00; A61L15/16; A61L15/42; A61L15/60; C; C08; C08F; C08F251/00; C08L; C08L3/00; C08L3/02; C08L51/00; C08L51/02
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
75 words
A method for preparing an extended starch-based superabsorbent material comprising: a. blending into an aqueous dispersion of a gelatinized starch-graft copolymer reaction product, either prior to or subsequent to saponification of said product, a dextrin extender characterized by an inherent viscosity in the range of about 0.05 to 0.60 dl./g. at 0.5% (w/v) in 1N NaOH; and b. drying the saponified blend to a moisture content of from about 1 to 15% water by weight.
Claim 2
Independent Claim
75 words
A method for preparing an extended starch-based superabsorbent material comprising: a. blending into an aqueous dispersion of a gelatinized starch-graft copolymer reaction product, either prior to or subsequent to saponification of said product, a dextrin extender characterized by an inherent viscosity in the range of about 0.05 to 0.60 dl./g. at 0.5% (w/v) in 1N NaOH; and b. drying the saponified blend to a moisture content of from about 1 to 15% water by weight.
Claim 3
Dependent Claim
15 words
A method as described in claim 1 wherein sald blending step is prior to saponification.
Claim 4
Dependent Claim
15 words
A method as described in claim 1 wherein said blending step is subsequent to saponification.
Claim 5
Dependent Claim
24 words
A method as described in claim 1 wherein said dextrin is characterized by an inherent viscosity in the range of 0.05 to 0.25 dl./g.
Claim 6
Dependent Claim
33 words
A method as described in claim 1 wherein the ratio of said extender to said starch graft copolymer reaction product on a dry weight basis is in the range of 1:2 to 2:1.
Claim 7
Dependent Claim
33 words
A method as described in claim 1 wherein the ratio of said extender to said starch graft copolymer reaction product on a dry weight basis is in the range of 1:2 to 1:1.
Claim 8
Dependent Claim
12 words
An extended starch-based superabsorbent material prepared by the method of claim 1.
Claim 9
Dependent Claim
12 words
An extended starch-based superabsorbent material prepared by the method of claim 4.
Claim 10
Dependent Claim
12 words
An extended starch-based superabsorbent material prepared by the method of claim 5.
Claim 11
Dependent Claim
12 words
An extended starch-based superabsorbent material prepared by the method of claim 6.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1987-11-20 | 1988-05-21 | 1988-11-20 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1991-11-20 | 1992-05-21 | 1992-11-20 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1995-11-20 | 1996-05-21 | 1996-11-20 | $7700.00 | Window Closed / Lapsed |