GB618449A - Manufacture of organic sulphur-containing polymers and novel cold-setting products obtained therefrom - Google Patents

Abstract

A process for the production of a liquid product suitable for the preparation of cold-setting compositions comprises esterifying a liquid disulphide acetal thioplast having terminal hydroxyl groups by heating an anhydrous mixture thereof with a dicarboxylic acid or an acid chloride or anhydride of such an acid and cooling the mixture after thickening occurs but before gelation sets in. The preparation of a suitable thioplast is described in Specification 618,440. The acid is preferably of the type HOOC-R-COOH, where R is an aliphatic hydrocarbon radical, a hydroxy derivative thereof, or an arylene radical or an anhydride of such an acid. Particularly suitable are acids where R is an aliphatic hydrocarbon radical or hydroxy derivative thereof containing 2-6 carbon atoms, e.g. succinic, tartaric, maleic and adipic acids, and where R is an arylene radical, such acids as phthalic and terephthalic. Suitable anhydrides are succinic, maleic, adipic and phthalic. In the esterification catalysts such as sulphuric acid, orthophosphoric acid, benzenesulphonic acid or toluene sulphonic acid may be used, and afterwards removed by washing with water or by neutralization. A cold setting composition is obtained by mixing the product with a divalent metal oxide, in amount one to two parts for every part of the liquid. Suitable oxides are zinc oxide, litharge, quicklime and magnesium oxide. In examples, in which the acid degraded thioplast prepared as in the example of Specification 618,440, is employed (1) the acid-degraded thioplast is heated with stirring with tartaric acid, cooled, and decanted from unreacted tartaric acid. One part of syrup mixed with 1.5 parts of zinc oxide is applied to a riveted joint in aluminium sheets, undergoing preliminary hardening in 40 minutes and forming a flexible coating in 3 days; (2) a mixture of acid-degraded thioplast after heating with phthalic anhydride is cooled and after mixing with zinc oxide and being applied to an aluminium sheet sets to a flexible coating in two days.