# US 5,702,631 A · Aqueous corrosion inhibitor formulations > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 5,702,631 A - Document ID: US5702631A - Status: Granted - Kind: A - Application number: 08/477,413 - Filed: 1995-06-07 - Granted: 1997-12-30 - Earliest claimed: 1992-11-24 - Assignees: Ashland Inc. - Inventors: John J. Conville; Robert Chwalik; Shrikant V. Desai; David E. Turcotte; James T. Lyon - Web page: https://patentgrep.com/patent/US5702631A ## CPC - C23F 11/08: in other liquids - C09K 5/08: Materials not undergoing a change of physical state when used (C09K5/16, C09K5/20 take precedence) - 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 - C09K: MATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE ## Abstract The present invention provides aqueous concentrated corrosion inhibition formulations suitable for addition to depleted antifreeze/coolant compositions or corrosive water that use a mixture of polymeric polycarboxylates, azoles, nitrate salts, phosphates, stabilized silicates and transition metal compounds which reduces the corrosion rate and is effective at relatively low concentrations. The formulations are particularly suitable for automotive applications. ## Claims ### Claim 1 An aqueous concentrated corrosion inhibitor solution for addition to glycol-based automotive antifreeze/coolant compositions having depleted corrosion-inhibiting characteristics, said solution consisting essentially of a corrosion inhibiting effective amount of: a polymeric polycarboxylate which is at least one selected from the group consisting of (i) a secondary alcohol modified polyacrylic acid, and (ii) a sodium salt of a copolymer of acrylic acid and maleic acid; a nitrate salt selected from sodium nitrate, potassium nitrate, magnesium nitrate, calcium nitrate and/or lithium nitrate; an azole compound selected from sodium mercaptobenzothiazole and sodium tolytriazole; a silicate compound; a transition metal compound selected from disodium salt dihydrate of molybdic acid, sodium molybdate.multidot.2H.sub.2 O, molybdenum trioxide, silicoheteropolymolybdates and/or phosphoroheteropolymolybdates; and a phosphate salt. ### Claim 2 (depends on 1) The aqueous concentrated corrosion inhibitor solution of claim 1, wherein said polymeric polycarboxylate is present in amount of between about 0.001% to about 10.0 wt. %. ### Claim 3 (depends on 1) The aqueous concentrated corrosion inhibitor solution of claim 1, wherein said polymeric polycarboxcylate has a molecular weight in a range of between about 500 to 12,000. ### Claim 4 (depends on 1) The aqueous concentrated corrosion inhibitor solution of claim 1, wherein said polymeric polycarboxcylate has a molecular weight in a range of between about 500 to 4,000. ### Claim 5 (depends on 1) The aqueous concentrated corrosion inhibitor solution of claim 1, wherein said polymeric polycarboxcylate has a molecular weight in a range of between about 500 to 1,800. ### Claim 6 (depends on 1) The aqueous concentrated corrosion inhibitor solution of claim 1, wherein said azole compound is a mixture of sodium mercaptobenzothiazole and sodium tolytriazole. ### Claim 7 (depends on 6) The aqueous concentrated corrosion inhibitor solution of claim 6, wherein said sodium mercaptobenzothiazole and sodium tolytriazole are present in a about a 3 to 1 ratio. ### Claim 8 (depends on 1) The aqueous concentrated corrosion inhibitor solution of claim 1, wherein said azole compound is present in a about a 50% concentration. ### Claim 9 (depends on 1) The aqueous concentrated corrosion inhibitor solution of claim 1, wherein said nitrate salt is sodium nitrate. ### Claim 10 (depends on 1) The aqueous concentrated corrosion inhibitor solution of claim 1, wherein said nitrate salt is present in an amount between about 1 wt % to about 10 wt %. ### Claim 11 (depends on 1) The aqueous concentrated corrosion inhibitor solution of claim 1, wherein said nitrate salt is present in an amount between about 1 wt % to about 3 wt %. ### Claim 12 (depends on 1) The aqueous concentrated corrosion inhibitor solution of claim 1, wherein said phosphate salt is at least one selected from the group consisting of dipotassium phosphate, disodium phosphate, monopotassium phosphate, tripotassium phosphate, monosodium phosphate, and trisodium phosphate. ### Claim 13 (depends on 1) The aqueous concentrated corrosion inhibitor solution of claim 1, wherein said phosphate salt is a dipotassium phosphate. ### Claim 14 (depends on 1) The aqueous concentrated corrosion inhibitor solution of claim 1, wherein said phosphate salt is present in about a 50% solution. ### Claim 15 (depends on 1) The aqueous concentrated corrosion inhibitor solution of claim 1, wherein said transition metal compound is the disodium salt dihydrate of molybdic acid. ### Claim 16 (depends on 1) The aqueous concentrated corrosion inhibitor solution of claim 1, including a defoamer. ### Claim 17 (depends on 16) The aqueous concentrated corrosion inhibitor solution of claim 16, wherein said defoamer is present in an amount between about 0.001 to about 10.0 wt. %. ### Claim 18 (depends on 1) The aqueous concentrated corrosion inhibitor solution of claim 1, including a bittering agent. ### Claim 19 (depends on 1) The aqueous concentrated corrosion inhibitor solution of claim 1, including a dye. ### Claim 20 (depends on 1) The aqueous concentrated corrosion inhibitor solution of claim 1, including a biocide. ### Claim 21 (depends on 1) The aqueous concentrated corrosion inhibitor solution of claim 1, wherein said silicate is present in an amount between about 0.1 to about 10.0 wt. %. ### Claim 22 (depends on 1) The aqueous concentrated corrosion inhibitor solution of claim 1, wherein said silicate is present in an amount between about 2.0 to about 6.0 wt. %. ### Claim 23 (depends on 1) The aqueous concentrated corrosion inhibitor solution of claim 1, wherein said aqueous concentrated corrosion inhibitor composition is added to an antifreeze coolant composition selected from the group consisting of ethylene glycol coolants, propylene glycol coolants, ethylene and propylene glycol coolant mixtures, water, silicate-phosphate coolants, silicate-borax coolants, amine phosphate coolants, amine-borax coolants, and organic acid-phosphate organic acid-borax coolants. ### Claim 24 (depends on 1) The concentrated corrosion inhibitor solution of claim 1, wherein said silicate is an aqueous silicate. ### Claim 25 (depends on 1) The concentrated corrosion inhibitor solution of claim 1, wherein the balance is water. ### Claim 26 An aqueous concentrated corrosion inhibitor solution for addition to glycol-based automotive antifreeze/coolant compositions having depleted corrosion-inhibiting characteristics, said solution consisting essentially of a corrosion inhibiting effective amount of: a polymeric polycarboxylate which is at least one selected from the group consisting of (i) a secondary alcohol modified polyacrylic acid, and (ii) a sodium salt of a copolymer of acrylic acid and maleic acid; a nitrate salt selected from sodium nitrate, potassium nitrate, magnesium nitrate, calcium nitrate and/or lithium nitrate; an azole compound selected from sodium mercaptobenzothiazole and sodium tolytriazole; a silicone-silicate copolymer; a transition metal compound selected from disodium salt dihydrate of molybdic acid, sodium molybdate.multidot.2H.sub.2 O, molybdenum trioxide, silicoheteropolymolybdates and/or phosphoroheteropolymolybdates; and a phosphate salt. ### Claim 27 (depends on 26) The aqueous concentrated corrosion inhibitor solution of claim 26, wherein said polymeric polycarboxylate is present in amount of between about 0.001% to abut 10.0 wt. %. ### Claim 28 (depends on 26) The aqueous concentrated corrosion inhibitor solution of claim 26, wherein said polymeric polycarboxylate has a molecular weight in a range of between about 500 to 12,000. ### Claim 29 (depends on 26) The aqueous concentrated corrosion inhibitor solution of claim 26, wherein said polymeric polycarboxylate has a molecular weight in a range of between about 500 to 4,000. ### Claim 30 (depends on 26) The aqueous concentrated corrosion inhibitor solution of claim 26, wherein said polymeric polycarboxylate has a molecular weight in a range of between about 500 to 1,800. ### Claim 31 (depends on 26) The aqueous concentrated corrosion inhibitor solution of claim 26, wherein said azole compound is a mixture of sodium mercaptobenzothiazole and sodium tolytriazole. ### Claim 32 (depends on 31) The aqueous concentrated corrosion inhibitor solution of claim 31, wherein said sodium mercaptobenzothiazole and sodium tolytriazole are present in a about a 3 to 1 ratio. ### Claim 33 (depends on 26) The aqueous concentrated corrosion inhibitor solution of claim 26, wherein said azole compound is present in a about a 50% concentration. ### Claim 34 (depends on 26) The aqueous concentrated corrosion inhibitor solution of claim 26, wherein said nitrate salt is sodium nitrate. ### Claim 35 (depends on 26) The aqueous concentrated corrosion inhibitor solution of claim 26, wherein said nitrate salt is present in an amount between about 1 wt % to about 10 wt %. ### Claim 36 (depends on 26) The aqueous concentrated corrosion inhibitor solution of claim 26, wherein said nitrate salt is present in an amount between about 1 wt % to about 3 wt %. ### Claim 37 (depends on 26) The aqueous concentrated corrosion inhibitor solution of claim 26, wherein said phosphate salt is at least one selected from the group consisting of dipotassium phosphate, disodium phosphate, monopotassium phosphate, tripotassium phosphate, monosodium phosphate, and trisodium phosphate. ### Claim 38 (depends on 26) The aqueous concentrated corrosion inhibitor solution of claim 26, wherein said phosphate salt is a dipotassium phosphate. ### Claim 39 (depends on 26) The aqueous concentrated corrosion inhibitor solution of claim 26, wherein said phosphate salt is present in about a 50% solution. ### Claim 40 (depends on 26) The aqueous concentrated corrosion inhibitor solution of claim 26, wherein said transition metal compound is the disodium salt dihydrate of molybdic acid. ### Claim 41 (depends on 26) The aqueous concentrated corrosion inhibitor solution of claim 26, including a defoamer. ### Claim 42 (depends on 41) The aqueous concentrated corrosion inhibitor solution of claim 41, wherein said defoamer is present in an amount between about 0.001 to about 10.0 wt. %. ### Claim 43 (depends on 26) The aqueous concentrated corrosion inhibitor solution of claim 26, including a bittering agent. ### Claim 44 (depends on 26) The aqueous concentrated corrosion inhibitor solution of claim 26, including a dye. ### Claim 45 (depends on 26) The aqueous concentrated corrosion inhibitor solution of claim 26, including a biocide. ### Claim 46 (depends on 26) The aqueous concentrated corrosion inhibitor solution of claim 26, wherein said silicone-silicate copolymer is present in an amount between abo`ut 0.1 to about 10.0 wt. %. ### Claim 47 (depends on 26) The aqueous concentrated corrosion inhibitor solution of claim 26, wherein said silicone-silicate copolymer is present in an amount between about 2.0 to about 6.0 wt. %. ### Claim 48 (depends on 26) The aqueous concentrated corrosion inhibitor solution of claim 26, wherein said aqueous concentrated corrosion inhibitor composition is added to an antifreeze coolant composition selected from the group consisting of ethylene glycol coolants, propylene glycol coolants, ethylene and propylene glycol coolant mixtures, water, silicate-phosphate coolants, silicate-borax coolants, amine phosphate coolants, amine-borax coolants, and organic acid-phosphate organic acid-borax coolants. ### Claim 49 (depends on 26) The concentrated corrosion inhibitor solution of claim 26, wherein said silicone-silicate copolymer is selected from the group consisting of alkali siliconate silylalkylphosphonates and salts thereof, arylalkyl silicone sulfonate-silicates and salts thereof, and sulfosiloxane-silicates and salts thereof. ### Claim 50 (depends on 26) The concentrated corrosion inhibitor solution of claim 26, wherein said silicone-silicate copolymer is an aqueous silicone-silicate compound said silicone-silicate compound being selected from the group consisting of alkali siliconate silylalkylphosphonates and salts thereof, arylalkyl silicone sulfonate-silicates and salts thereof, and sulfosiloxane-silicates and salts thereof. ### Claim 51 (depends on 26) The concentrated corrosion inhibitor solution of claim 26, wherein the balance is water.