Corrosion inhibitors and compositions containing them
AssigneeImperial Chemical Industries PLC
InventorsWilliam Boreland, John M. Dossor, Geoffrey S. Jaques
Life of this patent
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Abstract
Corrosion inhibitors for aqueous media comprise a triazole, an alkali metal borate, benzoate, and silicate and an alkali metal salt of a C.sub.7 to C.sub.13 dibasic acid. They may be used in antifreeze compositions for motor vehicles. Since neither nitrites and amines are required the danger of forming toxic nitrosamines by the reaction of these materials is overcome.
Claims12
A corrosion inhibitor which comprises:
- from 2 to 50 parts by weight of a triazole, an alkali metal borate in an amount sufficient to give a boron content of 5 to 60 parts by weight, from 100 to 500 parts by weight of an alkali metal benzoate or toluate, an alkali metal silicate sufficient to provide water soluble silicate and present in an amount of 1.5 to 15 parts by weight expressed as SiO.sub.2, and from 15 to 250 parts by weight, calculated as the free acid, of an alkali metal salt of a C.sub.7 to C.sub.13 dibasic organic acid, the corrosion inhibitor giving at a temperature of 25.degree. C. in a 2% solution in water a pH in the range 6.5 to 10.
An antifreeze composition which comprises a corrosion inhibitor as claimed in claim 1 and 10,000 parts by weight of the antifreeze component.
A heat exchange fluid which comprises an antifreeze composition as claimed in claim 5 or 6 and 0.5 to 5 parts by volume of water per part by volume of antifreeze composition.
Dependencies are inferred from the claim text.