| abstract |
A corrosion inhibiting composition comprising:n A) 40-90% by weight of a carboxylic acid corrosion inhibitor, or a water-soluble salt thereof, comprising one or more of:n A1) a triazine-carboxylic acid of formula I:n in which Z is a C₁-C₁₁ alkylene group, R₁ and R₂, independently, are hydrogen or methyl, and R₃ is a group -NR₄R₅ in which R₄ is C₁-C₁₂ alkyl or -Z-COOH in which Z has its previous significance, and R₅ is hydrogen or C₁-C₁₂ alkyl, or a water-soluble salt thereof; A2) a sulphonamidocarboxylic acid of formula II:n in which R₆ and R₇, independently, are hydrogen or C₁-C₄ alkyl, and m is an integer ranging from 1 to 10 or a water-soluble salt thereof; and A3) a dicarboxylic acid, or mixture thereof, having the formula III: n n HOOC-(CH₂) n -COOH III n nin which n is an integer ranging from 4 to 12, or a water-soluble salt thereof; B) 10-60% by weight of one or more aminobenzoic acids having the formula IV:n in which R₈ is hydrogen or a group of formula V or VI:n or one or more water-soluble salts thereof; C) 0-10% by weight of an alkanolamine of formula VII: n n NR₉R₁₀R₁₁ VII n nin which R₉,R₁₀ and R₁₁, independently, are hydrogen, a linear or branched C₁-C₁₂ alkyl group which is optionally interrupted by an oxygen atom, or R₉,R₁₀ and R₁₁ are a group of formula VIII:n where R₁₂ and R₁₃, independently, are hydrogen or C₁-C₁₂ alkyl and p and q, independently, are 0 or an integer ranging from 1 to 10, provided that p and q are not simultaneously 0 and provided that at least one of R₉,R₁₀ and R₁₁ is a group of formula VIII; and D) 0-10% by weight of an alkali metal borate; n the percentages by weight being based on the total weight of the corrosion inhibitor composition. |