| abstract |
The present invention provides a polyhydric alcohol antifreeze composition comprising A) as hard water deposition inhibitor, a hydrolyzed copolymer of maleic anhydride with a mono-ethylenically unsaturated monomer, or mixture of monomers, the molar ratio of maleic anhydride to other monomers being from 2.5:1 to 100:1, and the molecular weight of the copolymer being below 1000; and optionally B) as corrosion inhibitor, at least one of B-1) a triazine compound having the formula (I): ##STR1## wherein Z is a C 1 -C 11 alkylene group, X is hydrogen, an alkali metal or mono-, di- or tri-ethanolamine, R 1 and R 2 , independently, are hydrogen or methyl and R 3 is a group --NR 4 R 5 in which R 4 is C 1 -C 12 alkyl or --Z--COOX in which Z and X have their previous significance, and R 5 is hydrogen or C 1 -C 12 alkyl; B-2) 2-hydroxyphosphonoacetic acid; B-3) (2-Benzo-thiazolylthio)succinic acid and B-4) (2-benzothiazolylthio)-acetic acid. |