aq. ink erasing compsn. contg. sodium sulphite and soluble binder - has low mol. wt. alcohol, esp. ethanol, added to improve drying and writing surface quality

摘要

Ink-erasing compsn. is based on an S-contg. acid deriv. esp. Na sulphite in a water-soluble binder which is water-proof on drying, esp. a polyacrylate and/or styene copolymer, as in DT2616259. A low mol. wt. alcohol, pref. ethanol is now added so that the ratio H2O: alcohol is 1:1. Drying and the quality of the new writing surface are improved.