Patent US4561982A successfully refreshed from Google Patents.
US4561982A
Expired / Lapsed
US
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Scale inhibitor
Assignee: Mitsubishi Gas Chemical Co Inc
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Filing: 1983-10-19
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Granted: 1985-12-31
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Expires: 2003-10-19
Abstract
Abstract The present invention relates to a scale inhibitor for water and aqueous systems. The scale inhibitor comprising an oxidized polysaccharide containing, as the essential units, carboxyl group-bearing units of the formula: ##STR1## where A is CH 2 OR, R is H, (CH 2 ) n COOM or COOM, M is H, an alkali metal ion, or an ammonium group, and n is an integer from 1 to 3, obtained by the oxidative cleavage of polysaccharides containing 6-membered monosaccharide rings.
Inventors
- 👤 Yasuhisa Kuriyama
- 👤 Syoichiro Kajiwara
- 👤 Fumikazu Ozaki
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 15:16
CPC Classifications
C; C02; C02F; C02F5/00; C02F5/08; C02F5/10
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
112 words
A method for inhibiting scale in water and aqueous systems, comprising adding to said water or aqueous systems an oxidized polysaccharide in an amount in the range of 1 to 20 ppm, wherein said polysaccharide contains as the essential structural units, at least 10% of carboxyl group-bearing units of the formula: ##STR3## where A is CH 2 OR, R is H, (CH 2 ) n COOM or COOM, M is H, an alkali metal ion, or an ammonium group, n is a integer from 1 to 3, and said oxidized polysaccharide is obtained by the oxidative cleavage of a polysaccharide containing 6-membered monosaccharide rings having vicinal hydroxy groups with an oxidizing agent.
Claim 2
Independent Claim
112 words
A method for inhibiting scale in water and aqueous systems, comprising adding to said water or aqueous systems an oxidized polysaccharide in an amount in the range of 1 to 20 ppm, wherein said polysaccharide contains as the essential structural units, at least 10% of carboxyl group-bearing units of the formula: ##STR3## where A is CH 2 OR, R is H, (CH 2 ) n COOM or COOM, M is H, an alkali metal ion, or an ammonium group, n is a integer from 1 to 3, and said oxidized polysaccharide is obtained by the oxidative cleavage of a polysaccharide containing 6-membered monosaccharide rings having vicinal hydroxy groups with an oxidizing agent.
Claim 3
Dependent Claim
18 words
A method according to claim 1, wherein said oxidized polysaccharide contains at least 40% of carboxyl group-bearing units.
Claim 4
Dependent Claim
40 words
A method according to claim 1, wherein the polysaccharide containing 6-membered monosaccharide rings having vicinal hydroxy groups is a starch, dextrin, cellulose, sawdust, polyuronic acid, agar, natural gum, or a derivative thereof obtained by partial hydrolysis, esterification, etherification, or carboxylation.
Claim 5
Dependent Claim
26 words
A method according to claim 1, wherein the polysaccharide containing 6-membered monosaccharide rings having vicinal hydroxy groups is a starch, cellulose, or a carboxymethyl ether compound.
Claim 6
Independent Claim
77 words
A method according to any of claims 1 and 2, wherein sodium hypochlorite is used as an oxidizing agent in an amount such that the mole equivalents of the polysaccharide containing 6-membered rings having vicinal hydroxy groups to the effective chlorine content of the sodium hypochlorite is from 1:1 to 1:4, and the oxidative cleavage is conducted for one to several hours at room temperature or under heating, and at a pH in the range of 7-10.
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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) | 1988-12-30 | 1989-07-01 | 1989-12-31 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1992-12-30 | 1993-07-01 | 1993-12-31 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1996-12-30 | 1997-07-01 | 1997-12-31 | $7700.00 | Window Closed / Lapsed |