Aqueous polyurethane emulsions

Abstract

A method comprising I. reacting isocyanate groups in an organic polyisocyanate by anhydrous reaction with a chemically equivalent amount of primary hydroxyl-containing material, at least about 50 mole % of which material is one or a mixture of A. allyl alcohol, or B. at least one C.sub.2-4 hydroxyalkyl ester of acrylic or methacrylic acid, to form a water-resistant adduct of said polyisocyanate with said material, and Ii. intimately dispersing said adduct, in the form of a water insoluble liquid phase, into an aqueous liquid medium containing A. an anionic or cationic oil-in-water functioning emulsifying agent, in the presence of B. an aliphatic hydrocarbon or hydrocarbyl alcohol which is inert, non-volatile, water insoluble, liquid, and contains a terminal aliphatic hydrocarbyl group of at least about 8 carbon atoms; homogenizing the resulting crude emulsion to reduce the average size of the dispersed phase particles to below 0.5 .mu.; polymerizing the dispersed polyurethane particles in the resulting stable emulsion at suitable temperatures; coating substrates with the emulsions; the adducts, emulsions and coated substrates so produced.

Dependencies are inferred from the claim text.