US3596766A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Scale inhibition
Assignee: NL Industries Inc
•
Filing: 1969-03-28
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Granted: 1971-08-03
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Expires: 1989-03-28
Abstract
Abstract Potato starch, with or without an admixture of cellulose, is carboxymethylated by kneading, as in a dough mixer or extruder. The product is an excellent scale inhibitor for aqueous systems, being superior to other carboxymethylated starches.
Inventors
- 👤 Donald P Johnston
- 👤 Paul J Stone
- 👤 Jules Lee Magnon
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 22:16
CPC Classifications
C; C08; C08B; C08B31/00; C08B31/08; C08B31/12; C02; C02F; C02F5/00; C02F5/08; C02F5/10
Claims Analysis
Total Claims: 3
Claim 1
Independent Claim
14 words
The process in accordance with claim 1 wherein said kneading is accomplished by extrusion.
Claim 2
Dependent Claim
147 words
The process of inhibiting the deposition of scale from aqueous liquids containing substances having a tendency to precipitate out as scale which comprises the step of adding to said liquid, in an amount sufficient to substantially inhibit said scale formation, the product obtainable in accordance with the process of preparing a potato starch and cellulose derivative having enhanced scale-inhibiting properties which comprises the steps of kneading a mixture of cellulose and potato starch containing at least 10 percent by weight of said potato starch, together with from one-quarter to 1 1/2 times the weight of said cellulose-potato starch mixture of sodium chloroacetate and from about one-tenth to about one-quarter of the weight of said cellulose-potato starch mixture of sodium hydroxide, at a temperature of between 175* F. and about 320* F., until carboxymethylation of said cellulose-potato starch mixture is substantially complete; and recovering the product so obtained.
Claim 3
Dependent Claim
14 words
The process in accordance with claim 3 wherein said kneading is accomplished by extrusion.
References Cited (Backward Citations)
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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) | 1974-08-02 | 1975-02-01 | 1975-08-03 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-08-02 | 1979-02-01 | 1979-08-03 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-08-02 | 1983-02-01 | 1983-08-03 | $7700.00 | Window Closed / Lapsed |