Method for producing crystallized polyester

摘要

A method for producing a crystallized polyester comprises the crystallization step of applying a shear and/or a pressure to a polyester selected from an aliphatic polyester and a polyalkylene terephthalate at a temperature of (Tm−70° C.) to (Tm+20° C.), where Tm is a melting point of the polyester, thereby converting the polyester into a state having a crystallinity of 10% or more and fluidity.

主权项

1. A method for producing a crystallized polyester, which comprises a crystallization step of applying a shear and/or a pressure to a polyester, wherein the polyester is polylactic acid, in a molten state at a temperature of (Tm−70° C.) to (Tm−5° C.), where Tm is a melting point of the polyester, thereby converting the polyester into a state having a crystallinity of 10% or more and fluidity, wherein the state of having fluidity is a state having a melt viscosity of 1000 Pa·s or less, and the polyester to be subjected to the crystallization step has a weight average molecular weight of 5,000 to 100,000.