# US 10,246,622 B2 · Coolant having rapid metal passivation properties > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 10,246,622 B2 - Document ID: US10246622B2 - Status: Granted - Kind: B2 - Application number: 14/731,132 - Filed: 2015-06-04 - Published: 2015-09-24 - Granted: 2019-04-02 - Earliest claimed: 2012-09-05 - Assignees: Arteco NV - Applicants: Arteco NV - Inventors: Sandra G. Claeys; Serge S. Lievens - Web page: https://patentgrep.com/patent/US10246622B2 ## CPC - C09K 5/10: Liquid materials - C09K 5/20: Antifreeze additives therefor, e.g. for radiator liquids (for application to surfaces C09K3/18; inhibiting corrosion by liquids C23F11/00) - C23C 22/60: using alkaline aqueous solutions with pH greater than 8 - C23C 22/66: Treatment of aluminium or alloys based thereon - C23F 11/181: {Nitrogen containing compounds} - C23F 11/184: {Phosphorous, arsenic, antimony or bismuth containing compounds} - C23F 11/188: {containing phosphates} - C09K: MATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE - C23C: COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL (making metal-coated products by extrusion B21C23/22; covering with metal by connecting pre-existing layers to articles, see the relevant places, e.g. B21D39/00, B23K; metallising of glass C03C; metallising mortars, concrete, artificial stone, ceramics or natural stone C04B41/00; enamelling of, or applying a vitreous layer to, metals C23D; treating metal surfaces or coating of metals by electrolysis or electrophoresis C25D; single-crystal film growth C30B; by metallising textiles D06M11/83; decorating textiles by locally metallising D06Q1/04) - C23F: NON-MECHANICAL REMOVAL OF METALLIC MATERIAL FROM SURFACE (working metal by laser beams B23K26/00; desurfacing by applying flames B23K7/00; working of metal by electro-erosion B23H; producing decorative effects by removing surface material, e.g. by engraving, by etching, B44C1/22; electrolytic etching or polishing C25F); INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL; MULTI-STEP PROCESSES FOR SURFACE TREATMENT OF METALLIC MATERIAL INVOLVING AT LEAST ONE PROCESS PROVIDED FOR IN CLASS C23 AND AT LEAST ONE PROCESS COVERED BY SUBCLASS C21D OR C22F OR CLASS C25 ## Abstract It has been found that the chemical reactivity of the metal surface of heat exchangers with coolants in presence of nitrites can be reduced by the addition of additives such as phosphonates or phosphinates. Aluminum, other Group III metals, as well as other metals commonly used in cooling systems, such as those of automobile engines, may thus be effectively protected. ## Claims ### Claim 1 A heat transfer solution which provides passivation when placed in contact with metal surfaces, said solution comprising: (a) water, an alcohol, or a mixture of both; (b) from 0.01 to 1 wt % of a nitrite; (c) from 0.0001 to 1 wt % of a phosphonate or a phosphinate, the phosphonate having the formula R—[CR2]m—PO3M2 wherein each R-group is selected from the group consisting of hydrogen, alkyl, alkenyl, hydroxyl, phosphono group, carbonyl group, amino, alkylamino and an aryl group, wherein m is 1 or an integer greater than 1, and each M is hydrogen or an alkali metal ion; the phosphinate having the formula R—[CR2]m—P(O2M)H wherein each R-group is selected from the group consisting of hydrogen, alkyl, alkenyl, hydroxyl, phosphino group, carbonyl group, amino, alkylamino and an aryl group, wherein m is 1 or an integer greater than 1, and M is hydrogen or an alkali metal ion; (d) an alkaline earth metal compound; and (e) a corrosion inhibitor selected from the group consisting of 2-ethylhexanoic acid, sebacic acid, and mixtures thereof, wherein the heat transfer solution is free of inorganic phosphates. ### Claim 2 (depends on 1) The solution of claim 1, wherein the alcohol is water soluble. ### Claim 3 (depends on 2) The solution of claim 2, wherein the water soluble alcohol is selected from the group consisting of methanol, ethanol, propanol, ispropanol, butanol, glycols, glycol monoethers, glycerins and mixtures thereof. ### Claim 4 (depends on 3) The solution of claim 3, wherein the glycol is selected from the group consisting of ethylene glycol, diethylene glycol, propylene glycol, butylene glycol and mixtures thereof. ### Claim 5 (depends on 4) The solution of claim 4, wherein the glycol is ethylene glycol. ### Claim 6 (depends on 1) The solution of claim 1, wherein the solution further comprises a corrosion inhibitor salt which is selected from the group consisting of silicates, molybdates, nitrates, azoles and combinations thereof. ### Claim 7 (depends on 1) The solution of claim 1, which comprises from 50 to 99.8 wt % of the liquid of (a). ### Claim 8 (depends on 1) The solution of claim 1, wherein the nitrite is sodium nitrite. ### Claim 9 (depends on 1) The solution of claim 1 which further comprises additives selected from the group consisting of pH buffers, hard water stabilizers, antifoam agents, and colorants. ### Claim 10 (depends on 1) The solution of claim 1, wherein the alkaline earth metal compound is a strontium or magnesium compound. ### Claim 11 (depends on 1) The solution of claim 1, wherein the alkaline earth metal compound comprises strontium nitrate and (c) is a phosphonate which comprises 1-hydroxyethylidene-1,1-diphosphonic acid or phenylphosphonic acid. ### Claim 12 (depends on 1) The solution of claim 1, wherein (c) is a phosphonate and comprises 1-hydroxyethylidene-1,1-diphosphonic acid or phenylphosphonic acid. ### Claim 13 A process for passivation of metal surfaces, wherein the surfaces are treated with a solution comprising: (a) a liquid selected from the group consisting of water, an alcohol, and mixtures thereof; (b) from 0.01 to 1 wt % of a nitrite; (c) from 0.0001 to 1 wt % of: a phosphonate having the formula R—[CR2]m—PO3M2 wherein each R-group is selected from the group consisting of hydrogen, alkyl, alkenyl, hydroxyl, phosphono group, carbonyl group, amino, alkylamino and an aryl group, wherein m is 1 or an integer greater than 1, and each M is hydrogen or an alkali metal ion; or a phosphinate having the formula R—[CR2]m—P(O2M)H wherein each R-group is selected from the group consisting of hydrogen, alkyl, alkenyl, hydroxyl, phosphino group, carbonyl compound, amino, alkylamino and an aryl group, wherein m is 1 or an integer greater than 1, and M is hydrogen or an alkali metal ion; (d) an alkaline earth metal compound; and (e) and a corrosion inhibitor selected from the group consisting of 2-ethylhexanoic acid, sebacic acid, and mixtures thereof, wherein the solution is free of inorganic phosphates. ### Claim 14 (depends on 13) The process of claim 13, wherein the solution further comprises a corrosion inhibitor salt selected from the group consisting of silicates, molybdates, nitrates, azoles and combinations thereof. ### Claim 15 (depends on 13) The process of claim 13, wherein the alkaline earth metal compound comprises strontium nitrate and (c) is a phosphonate and comprises 1-hydroxyethylidene-1,1-diphosphonic acid or phenylphosphonic acid. ### Claim 16 (depends on 13) The process of claim 13, wherein (c) is a phosphonate and comprises 1-hydroxyethylidene-1,1-diphosphonic acid or phenylphosphonic acid. ### Claim 17 A heat transfer solution which provides passivation when placed in contact with metal surfaces, said solution comprising: (a) water, an alcohol, or a mixture of both; (b) from 0.01 to 1 wt % of a nitrite; (c) from 0.0001 to 1 wt % of a phosphonate having the formula R—[CR2]m—PO3M2 wherein each R-group is selected from the group consisting of hydrogen, alkyl, alkenyl, hydroxyl, phosphono group, carbonyl group, amino, alkylamino and an aryl group, wherein m is 1 or an integer greater than 1, and each M is hydrogen or an alkali metal ion; or a phosphinate having the formula R—[CR2]m—P(O2M)H wherein each R-group is selected from the group consisting of hydrogen, alkyl, alkenyl, hydroxyl, phosphino group, carbonyl group, amino, alkylamino and an aryl group, wherein m is 1 or an integer greater than 1, and M is hydrogen or an alkali metal ion; (d) an alkaline earth metal compound; and (e) a corrosion inhibitor, wherein the heat transfer solution is free of inorganic phosphates. ### Claim 18 (depends on 17) The solution of claim 17, wherein the solution further comprises a corrosion inhibitor salt which is selected from the group consisting of silicates, molybdates, nitrates, azoles and combinations thereof. ### Claim 19 (depends on 17) The solution of claim 17, which comprises from 50 to 99.8 wt % of the liquid of (a). ### Claim 20 (depends on 17) The solution of claim 17, wherein the corrosion inhibitor comprises the combination of an aliphatic monoacid or salt, a hydrocarbyl dibasic acid or salt and a hydrocarbyl triazole. ### Claim 21 (depends on 20) The solution of claim 20, wherein the corrosion inhibitor is selected from the group consisting of 2-ethylhexanoic acid, sebacic acid, tolyltriazole and mixtures thereof. ### Claim 22 A heat transfer solution which provides passivation when placed in contact with metal surfaces, said solution comprising: (a) water, an alcohol, or a mixture of both; (b) from 0.01 to 1 wt % of a nitrite; (c) from 0.0001 to 1 wt % of a phosphonate having the formula R—[CR2]m—PO3M2 wherein each R-group is selected from the group consisting of hydrogen, alkyl, alkenyl, hydroxyl, phosphono group, carbonyl group, amino, alkylamino and an aryl group, wherein m is 1 or an integer greater than 1, and each M is hydrogen or an alkali metal ion; or a phosphinate having the formula R—[CR2]m—P(O2M)H wherein each R-group is selected from the group consisting of hydrogen, alkyl, alkenyl, hydroxyl, phosphino group, carbonyl group, amino, alkylamino and an aryl group, wherein m is 1 or an integer greater than 1, and M is hydrogen or an alkali metal ion; (d) an alkaline earth metal compound; and (e) a corrosion inhibitor selected from the group consisting of 2-ethylhexanoic acid, sebacic acid, and mixtures thereof.