| 摘要 |
There is provided a method, copolymerizing a polyether segment in a molecular end of polyurethane, and being allowed the polymer to be phase-transitioned smoothly from a high-concentration organic solvent solution phase to an aqueous phase, for reducing the organic solvent solution significantly in emulsification step by acetone method and shortening the process time. Since a polyurethane resin of the present invention has a polyether segment copolymerized in the molecule, the solution viscosity of an organic solvent solution is reduced effectively. Further, since the ether segment exists at the molecular end, the polyurethane resin produced in an organic solvent phase during a water dispersion element production process is phase-transitioned smoothly from a high-concentration organic solvent solution phase to an aqueous phase. As a result, provided is the polyurethane resin in which the amount of an organic solvent to be distilled off can be reduced, and thus, the efficiency of production can be improved as a result of reduction in process time, environmental loads can be reduced as a result of reduction in the amount of organic solvent waste, and a stable water dispersion element can be formed. |
