MOISTURE-PERMEABLE FILM OR SHEET AND ITS PRODUCTION

摘要

PROBLEM TO BE SOLVED: To provide a film or sheet excellent in moisture permeability by molding a thermoplastic polyurethane resin in a simple step, provide a method for producing the film or sheet and further a method for producing a polyethylene glycol-based thermoplastic polyurethane resin used for the method. SOLUTION: This method for producing a thermoplastic polyurethane resin having >=5000 (g/m<2> .24hr) moisture permeability at 30μm thickness by reacting 50-70wt.% polyethylene glycol having 500-5000 number-average molecular weight with 50-30wt.% sum total of a chain extender and a polyisocyanate at a ratio of the number of mol of isocyanate groups in the polyisocyanate to the total number of mol of active hydrogen groups in the polyethylene glycol and the chain extender within the range of 0.9-1.2 without using a solvent. The moisture- permeable film or sheet is prepared by hot molding the thermoplastic polyurethane resin and a method for producing the film or sheet is provided.