| 摘要 |
PROBLEM TO BE SOLVED: To obtain a water-based urethane compound having excellent resin stability by chain-extending an aqueous dispersion of an unsaturated monomer solvent of a specified urethane prepolymer to form an aqueous dispersion of an unsaturated monomer solvent of a polyurethane and subjecting the entire mixture to polymerization. SOLUTION: A polyol (e.g. polypropylene glycol) is added to an unsaturated compound having an unsaturation and two hydroxyl groups (e.g. glycidol/methacrylic acid reaction product) and an unsaturated monomer (e.g. methyl methacrylate), the resulting mixture is reacted with an organic polyisocyanate (e.g. diphenylmethane diisocyanate) under agitation at about 50-100 deg.C in the presence of an organic tin catalyst to produce an unsaturated monomer solution of a urethane prepolymer having a molecular weight of 20,000 or below. This solution is mixed under agitation with a basic compound and water to form an aqueous dispersion of the unsaturated monomer solution of the urethane prepolymer. An aqueous solution of adipic acid hydrazide is further added to this aqueous dispersion, and the reaction is continued to form an aqueous dispersion of a polyurethane. Potassium persulfate is further added to the mixture, and the resulting mixture is subjected to an acrylic polymerization reaction to obtain a water-based urethane compound. |
