GB1327324A - Process and composition for removing rust - Google Patents

Abstract

1327324 Rust removal DOW CORNING CORP 7 Sept 1971 [15 Oct 1970] 41596/71 Heading C7E A rust remover composition comprises 1-12 wt. per cent HCl, 7À5-25% citric acid, 0À5-5% surfactant, 0À5-1À5% corrosion inhibitor, 0-6À5% thickener (optional), 0-0À2% defoamer (optional), and the balance water. The surfactant is preferably non-ionic, e.g. propylene glycol monostearate, glycerol monostearate, glycerol oleostearate, sorbitan monolaurate, sorbitan monopalmitate, sorbitan thioleate, polyoxyethylene sorbitol laurate, polyoxyethylene sorbitol oleotelaurate, nonylphenoxy polyoxyethylene ethanol, polyoxyethylene lauryl ether, myristic diethanol-amide, lauric diethanolamide, polyoxyethylene propylene glycol monostearate, iso-octylphenoxy polyoxyethylene ethanol, polyethylene glycol soybean fatty acid ester, tetrasodium EDTA, isopropyl myristate or dimethyl octynediol, but may be amphoteric, e.g. N-cocobeta-amino propionate Na salt, N-tallow-betaamino dipropionate di-Na-salt, N-lauryl-betaamino dipropionate disodium salt, N-laurylbeta-amino propionate Na salt, the triethanolamine salt of N-lauryl-beta-amino propionate, N-methyltaurine, sodium-N-methyltaurate, or cetyl betaine. The inhibitor may be an amine, e.g. N-cocobeta-aminobutyric acid, but can be Na 2 Cr 2 O 7 , propargyl alcohol, propargyl sulphide, or hydrazine. The thickener may be methyl cellulose, but is preferably colloidal SiO 2 ; the defoamer is a silicone or a higher alkyl alcohol. The composition is applied to a surface to be derusted, left to stand there, and subsequently removed, e.g. with water, to leave a clean surface inhibited against re-rusting.