Aqueous radiation curable polyurethane compositions

摘要

The invention relates to radiation-curable aqueous composition comprising a high molecular weight ethylenically unsaturated polyurethane obtained from the reaction of a polyisocyanate, at least one hydrophilic compound which is capable to render the polyurethane prepolymer dispersible in aqueous medium, an ethylenically unsaturated compound containing at least two reactive groups capable to react with isocyanate groups and an active hydrogen containing chain extender and a low molecular weight ethylenically unsaturated polyurethane end-capped with an ethylenically unsaturated compound containing essentially one reactive group capable to react with isocyanate groups.

主权项

1. An aqueous radiation-curable composition comprising
at least one high molecular weight ethylenically unsaturated polyurethane (A) obtained from the reaction of
at least one polyisocyanate compound (Ai),at least one ethylenically unsaturated compound (Aii) containing at least two reactive groups capable to react with isocyanate groups,at least one hydrophilic compound (Aiii) containing at least one reactive group capable to react with isocyanate groups and which is capable to render the polyurethane prepolymer dispersible in aqueous medium either directly or after the reaction with a neutralizing agent to provide a salt,at least one active hydrogen-containing chain extender (Avii) capable to react with isocyanate groups and provide chain extension, and,optionally one or more polyol (Avi), wherein the polyurethane (A) has a weight average molecular weight of more than 100000 Dalton; and at least one low molecular weight ethylenically unsaturated polyurethane (B), different from polyurethane (A), obtained from the reaction of
at least one polyisocyanate compound (Bi),at least one ethylenically unsaturated compound (Bii) containing at least two reactive groups capable to react with isocyanate groups,at least one hydrophilic compound (Biii) containing at least one reactive group capable to react with isocyanate groups and which is capable to render the polyurethane prepolymer dispersible in aqueous medium either directly or after the reaction with a neutralizing agent to provide a salt,at least one ethylenically unsaturated compound (Biv) containing one reactive group capable to react with isocyanate groups, and,optionally, one or more polyol (Bvi) and/or one or more active hydrogen-containing chain extender (Bvii), wherein the polyurethane (B) has a weight average molecular weight of 1000 to 100000 Dalton.