Claims
- 1. Composition for inhibiting scale in an aqueous system consisting essentially of (a) a member selected of the group consisting of copolymers of styrene sulfonic acid and maleic anhydride or maleic acid, and water soluble salts of said copolymers, the styrene sulfonic acid moiety in said copolymer being about 50-95 weight % and the molecular weight of the copolymers being about 1500-6000; and (b) a water soluble phosphonic acid and its water soluble salts; the weight ratio of copolymer to phosphonic acid being about 0.3-4:1.
- 2. Composition according to claim in 1 in which the moiety is about 67-90%.
- 3. Composition according to claim 1 in which the molecular weight is about 2000-4000.
- 4. Composition according to claim 1 in which the weight ratio of copolymer to phosphonic acid is about 0.5-1.5:1.
- 5. Composition according to any one of claims 1, 2, 3, or 4 in which the phosphonic acid is selected from the group consisting of hydroxyethylidene diphosphonic acid, nitrilo tri(methylene phosphonic acid), N-carboxymethyl imino di(methylene phosphonic acid), N,N-bis(carboxymethyl) amino methylene phosphonic acid, ethylene diamine tetra(methylene phosphonic acid), hydroxypropylidene diphosphonic acid, hexamethylenediamine tetra(methylene phosphonic acid), diethylenetriamine penta(methylene phosphonic acid), aminoethylidene diphosphonic acid, n-butyl amino di(ethyl phosphonic acid), isopropyl phosphonic acid, 2-phosphono butane tricarboxylic acid-1,2,4, 2-aminoethyl phosphonic acid, sodium salt of tetraethylenepentamine hepta(methylene phosphonic acid), and methylene diphosphonic acid.
- 6. Composition for inhibiting scale in an aqueous system which consists essentially of (a) a member selected of the group consisting of copolymers of styrene sulfonic acid and maleic anhydride or maleic acid, and water soluble salts of said copolymers, the styrene sulfonic acid moiety in said copolymer being about 67-90% and the molecular weight of the copolymers being about 2000-4000; and (b) a member selected from a group consisting of hydroxyethylidene diphosphonic acid and its water soluble salts; the weight ratio of copolymer to hydroxyethylidene phosphonic acid being about 0.3-4:1.
- 7. Composition according to any one of claims 1, 2, 3, 4, or 6 in which the maleic component in the copolymer is maleic anhydride.
- 8. Composition according to any one of claims 1, 2, 3, 4, or 6 in which the maleic component in the copolymer is maleic acid.
Parent Case Info
This is a division of application Ser. No. 76,810, filed Sept. 18, 1979, now U.S. Pat. No. 4,255,259, which is a continuation-in-part of our copending application Ser. No. 915,713, filed June 15, 1978, now abandoned, the contents of which are incorporated herein by reference.
US Referenced Citations (14)
Foreign Referenced Citations (3)
Number |
Date |
Country |
845937 |
Dec 1976 |
BEX |
1534596 |
Dec 1978 |
GBX |
2023121 |
Dec 1979 |
GBX |
Divisions (1)
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Number |
Date |
Country |
Parent |
76810 |
Sep 1979 |
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Continuation in Parts (1)
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Number |
Date |
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Parent |
915713 |
Jun 1978 |
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