GB405603A - Improvements in or relating to printing compositions - Google Patents

Abstract

Resins for use as an ingredient of viscous, quick-drying printing-compositions are prepared by heating together a polyhydric alcohol, a polybasic acid, and drying or semi-drying oil acids, or by heating the alcohol and oil together until a single phase is formed, and then adding the acid and heating until resinification occurs. The resins preferably contain 40 to 85 per cent of oil or oil acids, those containing below 55 per cent being suitable for use in printing-enamels, and those containing more than 55 per cent being suitable for use in inks. The resin may be formed from glycerol, glycol, pentaerythritol, mannitol, or a polyglycol, and phthalic, succinic, malic, maleic, fumaric, tartaric, or citric acid. The viscosity can be varied by altering the time and temperature of the reaction. According to examples printing-ink resins are prepared (1) by heating together phthalic anhydride, glycerol, and linseed oil fatty acids in the presence of carbon dioxide until an acid number of not more than 10 is obtained; (2) by heating together in an atmosphere of carbon dioxide a mixture of glycerol and caustic soda with linseed oil until a sample is clear, and then adding phthalic anhydride until an acid number of 5 is obtained; and printing-enamel resins are prepared (1) by heating together phthalic anhydride, glycerol, linseed oil acids, and china wood oil until an acid number of 37 to 42 is obtained, the mixture being then thinned with naphtha and centrifuged; (2) by heating together glycerol, linseed oil, and p china wood oil, adding a mixture of linseed oil and litharge, heating until the mixture is clear, adding phthalic anhydride, heating until an acid number of 35 to 40 is obtained and finally thinning with naphtha and centrifuging.