Particle dispersibility improvement of polyester fibers with a new line injection

In order to develop a new line injection system for spin draw yarn (FD SDY) fibers, the effect of various parameters in extrusion and melt line conditions on the dispersion and distribution of TiO₂ particles within FD PET fibers was investigated. As a result, the dispersibility of TiO₂ particles in a PET matrix is found to depend on the particle size and its surface characteristics. Surface modification of TiO₂ by dimethyl polysiloxane resulted in the improved dispersibility and affinity of TiO ₂ particles in the PET matrix. Especially, residence time, mixing temperature, and mixing shear rate in the new line injection system under the SDY spinning process were very important parameters to minimize the agglomeration of TiO2 particles. The FD SDY prepared by the new line injection system was superior to those using the polymerization process and the conventional masterbatch chip dosing process in the color-L and color-b values of the fibers.