Aqueous corrosion inhibitor formulations
AssigneeAshland Inc.
InventorsJohn J. Conville, Robert Chwalik, Shrikant V. Desai, David E. Turcotte, James T. Lyon
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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.
Claims51
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.
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.
Dependencies are inferred from the claim text.