Starch modified with water soluble acyl thiosulphates - has good dispersion and stiffening properties, used esp. for sizing of paper and in textile finishes

摘要

Hydrophobic starch esters are made by reacting unstiffened starch with a cpd. R-CO-S-SO2-OH (I) in which R = cycloalkyl, (substd) aryl gp. or arylalkyl gp. and X is H or a salt forming ion, in the presence of an alkaline catalyst. Pref. the starch is reacted with a benzoylthiosulphate salt or a benzyloxycarbonylthiosulphate salt in aq. medium. The starch derivs. are easier to disperse and to stiffen than hydrophobic starch derivs. made with the same degree of substitution but using water-insoluble reagents. The prods. are useful for stiffening and finishing textile fabrics, for bulk- and surface sizing of paper, and as adhesives and binders for various granular and fibrous materials.