The characterics of PET/PBT bi-component yarn

The crimp of general chemical fiber is formed by heat setting,which has a bad durability and stretch recovery,so it has bad cohesive force is bad and not good for subsequent processing.PBT/PET paralleling composite fiber is not like the generous fiber,the cross-section has two material with different shrinkage,

This different shrinkage rate from different polymer in two side of the yarn makes the fiber has everlasting crimp.The foundation of this feature is the dissymmetry distribution of the two material and the characterics of the polymer itself.In theory,the compenent of higher shrinkage is in the inside of the spiral and the lower shrinkage is in the outside

The difference of shrinkage of two components is connected with chemical content of macro molecule chain ,tensile and condition of heat-seting formability.This bi-component fiber has good crimp after loose heat setting,and has high elasticity and stretch recovery.

PBT is the shrinking part of bi-component fiber,due to its high degree of crystallinity and elasticity,when stretch the fiber,the molecule chain section of crystalline region tends to change its shape,however not cause relative displacement,thus the struction is remain stable.When remove the external force,the fiber will return the initial state,this is the foundation of good elasticity and stretch recovery of the bi-component fiber.