W/O POLYURETHANE EMULSION AND PRODUCTION OF POROUS SHEET MATERIAL BY USING SAME

摘要

PURPOSE:To obtain a porous sheet material of stable quality by using a W/O polyurethane emulsion containing a specified hydrophilic polyurethane having particles as the principal component and containing a small amount of a specified hydrophilic modified polyurethane as an emulsifier component. CONSTITUTION:A W/O polyurethane emulsion containing a hydrophobic polyurethane, a hydrophilic modified polyurethane, an organic solvent and water. The hydrophilic polyurethane comprises a particle-containing polyurethane dispersion obtained by reacting a hydrophobic polyol with an organic diisocyanate and a chain extender in the above solvent having a solubility in water at 25 deg.C in a range of 1-50g/100g water to form a solution of a polyurethane of an average mol.wt. of 5000-200000 and reacting an organic polyisocyanate with ethylene glycol in the polyurethane solution. The hydrophilic modified polyurethane comprises a modified polyurethane prepared by copolymerizing a double bond- containing polyurethane terminated with a vinyl monomer having one isocyanate or hydroxyl group in the molecule with a hydrophilic vinyl monomer.