PURPOSE: To obtain a polyester fiber having excellent dyeability and alkali resistance while keeping the characteristic excellent properties of polyester by copolymerizing a specific diol component to a polyethylene terephthalate.
CONSTITUTION: A polyester having an intrinsic viscosity of 0.5-0.8 is produced by copolymerizing terephthalic acid, ethylene glycol and a 2,2-alkyl-substituted 1,3-propanediol compound. The fiber or film produced from the polyester keeps the characteristic excellent properties of polyester and exhibits improved dyeability and high alkali resistance which cannot be attained by the conventional process. The propanediol component is used at a molar ratio of 3-40 based on the total diol component and the alkyl group is preferably selected from ethyl, propyl, butyl and pentyl.
HANZAWA FUSAO
IDE SEIJI
TAKAHASHI ATSUSHI
