Process for producing a microporous polyamino acid urethane resin film

摘要

The present invention relates to a process for producing a microporous film which is superior with regard to moisture permeability, heat resistance and elasticity and is obtained by the dry process and use of a water-in-oil emulsion of a polyamino acid urethane resin solution. The conventional polyurethane resin was superior in physical properties, such as elasticity and low temperature resistance, but a microporous film obtained from this resin shows disadvantages in properties such as moisture permeability and heat resistance. The present invention was made as a result of research concerned with improving these disadvantages, and creates a process for producing a microporous polyamino acid urethane resin film which is characterised in that an alkyl ester group in a polyamino acid urethane resin obtained by the copolymerisation of a urethane prepolymer with a terminal amino group and an acid amino acid alkyl ester N-carboxylic anhydride in an organic solvent was reacted on at least one kind of ammonium, hydrazine, monoamine and diamine in order that a hydrophilic property may be conferred, and then a water-in-oil emulsion of the polyamino acid urethane resin obtained by adding water to the resin solution was applied to a substrate and dried.