| 摘要 |
The present invention provides a process for producing a polyurethane emulsion, capable of continuously producing a polyurethane emulsion which contains substantially no organic solvent and also has excellent storage stability over time. Disclosed is a process for producing a polyurethane emulsion by emulsifying a urethane prepolymer, which contains substantially no organic solvent and also has at least two isocyanate groups per one molecule, with water and completing chain extension, the process comprising (1) a first step of supplying the urethane prepolymer and water in an emulsifying apparatus comprising a stator section 5 fixed inside a cylindrical casing 1 and a rotor section 3 fixed to a rotational shaft 2 in the casing 1, the rotor section 3 having multiple rotor teeth 4, the stator section 5 having multiple stator teeth 6, which stand face to face with the rotor teeth 4, the stator section 5 having an inlet 8 and an outlet 10, from the inlet 8, continuously emulsifying them to obtain an emulsion of the urethane prepolymer having an average particle size of 0.1 to 2.5 mu m, and discharging the emulsion from the outlet 10, and (2) a second step of reacting the emulsion of the urethane prepolymer obtained in the first step with a chain extender, thereby completing chain extension of the urethane prepolymer. <IMAGE>
|
