| 摘要 |
PROBLEM TO BE SOLVED: To provide a method for producing aqueous dispersion of polyurethane resin free from organic solvents, excellent in physical properties of a dried film, and to provide an aqueous dispersion of the polyurethane resin obtained by the same. SOLUTION: The invention relates to the method for producing aqueous dispersion (Q2) of polyurethane resin composed of a polyurethane resin with 0.01-5μm of volume average particle size comprising a step obtaining an aqueous dispersion (Q1) of polyurethane resin with 0.1-100μm of volume average particle size by dispersing a solid polyurethane prepolymer with more than 0.5 wt.% of terminal isocyanate groups which is obtained without using organic solvents, by using one or more kinds of dispersing/mixing devices (A1) at a temperature below melting point of the polyurethane prepolymer in water, and a step dispersing the product dispersion using one or more kinds of dispersing/mixing devices (A2) with a different dispersing system from the dispersing/mixing device (A1) at a temperature below melting point of the polyurethane prepolymer to disperse until the dispersion has 1/2-1/1,000 of volume average particle size. COPYRIGHT: (C)2008,JPO&INPIT
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