POLYURETHANE DISPERSION HAVING WATER ABSORPTION AND ITS PRODUCTION

摘要

PROBLEM TO BE SOLVED: To obtain the subject dispersion suitable for forming a hydrophilic film having water absorption ability and excellent water resistance, by stably dispersing specific cross-linked polyurethane particles into water and/or an alcohol. SOLUTION: This dispersion is obtained by dispersing crosslinked polyurethane particles having 0.01-2μm average particle diameter constituted of (A) a polyoxyethylene-containing polyamine and (B) a water-dispersible polyisocyanate as essential components into water and/or an alcohol. The component A is at least one polyamine selected from polyamines of formula I and formula II ((n), (m) and (k) are each the polymerization degree to make its molecular weight) having 500-20,000 molecular weight and 50-99 wt.% polyoxyethylene content. In producing the obtainable dispersion, the reaction is preferably carried out under conditions that the ratio of the functional group of the isocyanate group in the component B to the amino group in the component A is 0.7 <= isocyanate group/amino group <= 1.4.