POLYESTER GRANULE FOR MELT-SHAPING AND PROCESS FOR THE PREPARATION THEREOF

摘要

Polyester granule for melt-shaping which is composed of a difficultly crystallizable copolyester having the minimum time for half-crystallization of at least one minute, and has the surfaces resulting from cutting by a cutter, improvement in that (i) the polyester granule has an intrinsic viscosity of at least 0.55 (as measured in o-chlorophenol at 35.degree.C.), (ii) the polyester granule has in its surface portion an oriented portion having an N-value of at least 0.04, the N-value being calculated by the equation, N = n??d and (iii) the inside of the polyester granule other than the said surface portion has an N-value of not higher than 0.02. Said polyester granule can be prepared by cutting a copolyester melt-extrudate having an intrinsic viscosity of at least 0.55 under the conditions as will control the surface temperature t (.degree.C) of the extrudate to satisfy the expression Tg + 30.degree.C. ? t > Tg - 15.degree.C.