Silicate-, borate- and nitrate-free antifreeze concentrates and coolant compositions comprising them

摘要

An antifreeze concentrate based on alkylene glycols or their derivatives is free from silicate, borate and nitrate contains (a) 0.05-10 wt.% 3-16 C carboxylic acid(s) in the form of alkali metal or (substituted) ammonium salt(s) and (b) 0.01-3 wt.% hydrocarbotriazole(s) and/or hydrocarbothiazole(s), especially benzotriazole and/or tolutriazole. Also claimed is a ready-to-use aqueous antifreeze composition containing water and 10-90 wt.% of the concentrate.