Patent GB-478338-A (GB)
Title: Improvements in or relating to the inhibition of corrosion of metals
Filed: 1936-04-09
Abstract: The corrosion of metallic surfaces, particularly ferrous metal surfaces, is inhibited by treating them with a composition consisting of or containing certain organic esters of phosphorus acids such as ortho-, meta-, or pyrophosphoric acid, phosphorous acid, hypophosphorous acid and thiophosphoric acid.  The esters which can be used comprise the cycloaliphatic and long chain aliphatic mono-esters; simple and mixed long chain aliphatic, cycloaliphatic, and aromatic di-esters; mixed long chain aliphatic-aromatic di-esters; mixed cycloaliphatic-aromatic di-esters; simple and mixed aromatic tri-esters; mixed long chain aliphatic-lower aliphatic poly-esters containing not more than one long chain radical; mixed cycloaliphatic-lower aliphatic poly-esters containing not more than one cycloaliphatic radical; and mixed lower aliphatic-aromatic poly-esters.  Mixtures of any of these with the less volatile lower aliphatic esters may also be used.  The compositions used for treating the metal preferably comprise a large proportion of a carrier such as an oily substance mixed with a small proportion, e.g. 0,05--10 per cent, of the ester.  Examples of carriers are light oils of the spindle oil type, light or medium lubricating oils, glycerin-diphenyl, diphenyl oxide, benzene, solvent naphtha, petrol, and liquid hydrocarbons, oils and waxes generally.  Examples are given describing (a) the oiling of gun barrels with a mixture of 99 parts of spindle oil and 1 part of dicresyl phosphate, (b) the oiling of steel wood-working tools with a mixture of 98 parts of lubricating oil and 2 parts of dilorol phosphate, (c) the coating of an automobile fender with the composition used in (b).  A long list is given of particular esters which may be used in the process. Emulsions of the esters with water or with water and oil may be used.ALSO:The corrosion of metallic surfaces, particularly ferrous metal surfaces, is inhibited by treating them with a composition consisting of or containing certain organic esters of phosphorous acids such as ortho-, meta-, or pyrophosphoric acid, phosphorous acid, hypophosphorous acid and thiophosphoric acid.  The esters which can be used comprise the cycloaliphatic and long chain aliphatic mono-esters; simple and mixed long chain aliphatic, cycloaliphatic, and aromatic di-esters; mixed long chain aliphatic-aromatic di-esters; mixed cycloaliphatic-aromatic di-esters; simple and mixed aromatic tri-esters; mixed long chain aliphaticlower aliphatic poly-esters containing not more than one long chain radical; mixed cycloaliphatic-lower aliphatic polyesters containing not more than one cycloaliphatic radical; and mixed lower aliphatic-aromatic poly-esters.  Mixtures of any of these with the less volatile lower aliphatic esters may also be used.  The compositions used for treating the metal preferably comprise a large proportion of a carrier such as an oily substance mixed with a small proportion, e.g. 0,05-10 per cent, of the ester.  Examples of carriers are light oils of the spindle oil type, light or medium lubricating oils, glycerin-diphenyl, diphenyl oxide, benzene, solvent naphtha, petrol, and liquid hydrocarbons, oils and waxes generally.  Examples are given describing (a) the oiling of gun barrels with a mixture of 99 parts of spindle oil and 1 part of dicresyl phosphate, (b) the oiling of steel wood-working tools with a mixture of 98 parts of lubricating oil and 2 parts of dilorol phosphate, (c) the coating of an automobile fender with the composition used in (b).  The esters or the compositions containing them may be added to aqueous solutions to inhibit corrosion of metal parts coming into contact therewith, one or more emulsifying agents such as soap, sulphonated oils, or fatty alcohol sulphate esters being preferably also added.  For example, a 35 per cent solution of glycerin in water may be rendered substantially non-corrosive by the addition of 0,5 per cent of a mixture of 94 parts self-emulsifying oil, 5 parts o-toluidine, and 1 part of tri-cresyl or dilauryl phosphate.  A long list is given of particular esters which may be used in the process.  Emulsions of the esters with water or with water and oil may be used.