| 摘要 |
PROBLEM TO BE SOLVED: To provide a composite resin emulsion of polyurethane and a polymer of an ethylenically unsaturated monomer which forms films and the like excellent in dispersion stability, transparency, flexibility, mechanical characteristics, abrasion resistance, weatherability, flexing resistance, solvent resistance and hydrolysis resistance and its preparation method; and a composite resin emulsion which further comprises a heat-sensitive gelling agent. SOLUTION: A method for preparing a composite resin emulsion comprises conducting emulsion polymerization of an ethylenically unsaturated monomer in the presence of a polyurethane-based emulsion which satisfies the following requirements (1) to (3): (1) it is prepared by reacting a chain extender with an isocyanate-terminated urethane prepolymer in the presence of a surfactant in an aqueous liquid, (2) it has 3-30 mmol of neutralized carboxyl groups and/or sulfonic groups in the polyurethane skeleton per 100 g of the polyurethane and (3) it contains 0.5-10 g of a surfactant per 100 g of the polyurethane. The composite resin emulsion contains or does not contain a heat-sensitive gelling agent.
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