Water treating process
AssigneesKurita Water Industries Ltd., Sanyo Chemical Industries, Ltd.
InventorsMotohiko Ii, Yoshio Goto, Takashi Suzuki, Sotoo Kubo
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Abstract
A water treating agent which comprises a specific polymer containing a structural unit that is derived from a monomer having an ethylenically unsaturated bond and has one or more carboxyl radicals, at least a part of said carboxyl radicals being modified, or another water treating agent which comprises, in addition to said specific polymer, one or more compounds selected from the group consisting of inorganic phosphates, phosphonic acids, organic phosphoric acid esters and polyvalent metal salts, is capable of preventing the formation of corrosion, scale and contamination on the surface of a metal that is in contact with water.
Claims21
A process for treating water to inhibit formation of scale and deposits on surfaces in contact with the water and to minimize corrosion of said surfaces, which comprises:
- mixing in the water
- (a) an effective amount of water-soluble polymer having a molecular weight of from 500 to 200,000, said polymer consisting essentially of structural units derived from a monomer having an ethylenically unsaturated bond and one or more carboxyl radicals wherein from 10 to 100% of said carboxyl radicals are modified to have the formula
- --CO(OA).sub.a X
- or the formula ##STR14## wherein OA is oxyalkylene having 2 to 4 carbon atoms;
- X is hydroxy, alkoxy having 1 to 4 carbon atoms or monovalent phosphate radical;
- X.sup.1 is a divalent phosphate radical;
- and "a" is a positive integer;
- and wherein the remainder of said carboxyl radicals are water-soluble salts thereof with monovalent cations;
- and
- (b) an effective amount of one or more corrosion inhibitor compounds selected from the group consisting of inorganic phosphoric acids and water-soluble salts thereof, phosphonic acids and water-soluble salts thereof, organic phosphoric acid esters and water-soluble salts thereof, and polyvalent metal salts capable of being dissociated to polyvalent metal ions in water.
A water system having dissolved therein an effective amount of a water treating composition to inhibit formation of scale and deposits on surfaces in contact with the water and to minimize corrosion of said surfaces, said water treating composition comprising:
- (a) an effective amount of water-soluble polymer having a molecular weight of from 500 to 200,000, said polymer consisting essentially of structural units derived from a monomer having an ethylenically unsaturated bond and one or more carboxyl radicals wherein from 10 to 100% of said carboxyl radicals are modified to have the formula
- --CO(OA).sub.a X
- or the formula ##STR27## wherein OA is oxyalkylene having 2 to 4 carbon atoms;
- X is hydroxy, alkoxy having 1 to 4 carbon atoms or monovalent phosphate radical;
- X.sup.1 is a divalent phosphate radical;
- and "a" is a positive integer;
- and wherein the remainder of said carboxyl radicals are water-soluble salts thereof with monovalent cations;
- and
- (b) an effective amount of one or more corrosion inhibitor compounds selected from the group consisting of inorganic phosphoric acids and water-soluble salts thereof, phosphonic acids and water-soluble salts thereof, organic phosphoric acid esters and water-soluble salts thereof, and polyvalent metal salts capable of being dissociated to polyvalent metal ions in water.
Dependencies are inferred from the claim text.