Characterization For Crimp Mechanism Of PTT/PET Bi-component Filament And Its Fabric Performance

With material of low melting point PTT chips and normal PET chips, PTT/PET bi-component filament is produced by means of side by side spin pack. It has elasticity with three-dimensional crimp structure by heat-moisture treatment, because of different shrinkage of two components. It is a new textile material to design elastic fabric. In this paper, the crimp mechanism of PTT/PET bi-component filament had been done on the both theory and experiment. The elasticity and style features of woven fabric with PTT/PET bi-component filament or polyurethane fiber were measured and compared. First, based on two typical cross-sections such as the circular and the near-elliptical of PTT/PET bi-component filament, the crimp modeling was established. It can be used to describe the relationship among the crimp morphology in longitudinal, the cross-section characteristics and the shrinkage difference of two component: 1/ρ=(u1+d)/((u1)~2+(u1+d)~2+ω((u2)~2+(u2-d)~2)ΔSecondly, by the technique of Matlab, Jcad and Photoshop, the cross section characteristic of PTT/PET bi-component filament with nearly elliptical cross section was obtained and it lead the relationship between the crimp morphology in longitudinal and the shrinkage difference of two component. The average ofρΔis 17.46μm.Third, the crimp radius, the number of crimp, which is the characterization parameter of the crimp morphology in longitudinal, and the elastic elongation, elastic recovery of PTT/PET bi-component filament by heat-moisture treatment in different temperature and time were measured and the shrinkage difference of two components was calculated in this paper.(1) The crimp radius of PTT/PET bi-component filament decrease and their number of crimp increase with increasing the treatment temperature. The effect of treatment temperature to the characterization parameter of the crimp morphology in longitudinal is more obvious than the treatment time.(2) Assuming the cross-section characteristics with heat-moisture treatment was fixed. The shrinkage difference the two component increases with rising the treatment temperature.(3) 20% of the elastic elongation of the PTT/PET bi-component filament can be obtained by heat-moisture treatment. But it decreases with increasing the treatment temperature. The filament has 95% of the elastic recovery and it is stability.Finally, the elongation, elastic recovery rate and the drape coefficient, bending stiffness, wrinkle recovery angle of the fabrics with PTT/PET bi-component filament or polyurethane fiber were measured and compared.(1) The fabrics with PTT/PET bi-component filament have appropriate the elongation and excellent elastic recovery rate. For the high heavy cotton stretch denim fabric, they have the same less than 10% of elongation as the fabrics with polyurethane fiber. For the medium thick fabrics, the range of their elongation is from 10% to 15%, while the elongation of fabric with polyurethane fiber is greater than 20%. The fabrics with PTT/PET bi-component filament has larger elastic recovery rate than that with polyurethane fiber.(2) Drape properties, bending properties and crease recovery were affected by the yarn character, the fabric tightness, yarn linear density, fabric density, fabric weave, fabric weight and ect.The drape coefficient and bending stiffness of the high heavy cotton stretch denim fabrics with PTT/PET bi-component filament are larger than that with polyurethane fiber. The drape coefficient of the former is less than that of the latter.The both fabrics with PTT/PET bi-component filament and polyurethane fiber have excellent elastic recovery rate. The wrinkle recovery angles of the fabrics in weft increase as the weft of the fabric are employed with above two fibers. Furthermore PTT/PET bi-component filament could provide better crease recovery than polyurethane fiber.