Deriving an empirical formula to determine the optimum level of false-twist in mechanically-crimped textured polyester yarn

Abstract

Flat polyester yarn is bulked by the mechanical crimp texturizing process. The magnitude of the false-twist, introduced together with the torsional rigidity of the supply yarn, has a significant effect on the transformation process. The torsional rigidity of the supply yarn is in turn influenced by its fineness and bending characteristics. It is therefore deemed necessary to establish a mathematical relationship between the optimum false-twist level and the yarn fineness for materials with known bending characteristics. Such a relationship may help in producing a yarn with optimum bulk properties, while minimizing resource utilization and waste generation. This paper reports research work done in this direction. Polyester yarn is chosen for this investigation as it has a wide range of applications. Fully drawn multifilament polyester yarns, with different linear densities, are textured on a single-head mechanical crimp texturing machine. The results are analysed with the help of polynomial curve fitting (Polyfit) using MATLAB. This mathematical tool facilitated the derivation of the desired formula (polynomial equation) for the calculation of optimum false-twist level for fully drawn multifilament polyester yarns undergoing mechanical crimp texturizing.

Mechanical crimp texturizing of non-thermoplastic viscose rayon yarn

“…18 Improved orientation on under feeding and added binding forces due to the presence of real twist in the structure had retained almost identical tenacity of the textured yarns to that of their respective parent yarns. 16,18 The linear density of textured yarn is found to be same as that of the parent yarn, which is due to combined effect of pre-twisting, crimping and under feeding. 15,18 Comparative cost analysis of three texturizing systems had put this mechanical concept next to cheaper false-twist texturizing due to obviation of cost adding factors.…”

“…The mechanical crimp texturizing concept was introduced by Shaikh et al, [15][16][17][18] by linking concepts of false-twist texturizing and air jet texturizing. This technique is still at the experimental stage.…”

“…Its basic concept and the outcome of research done on polyester and nylon have been briefly reviewed. [15][16][17][18] Basic concept Pre-twisted FDY (Fully Drawn Yarn) flat multifilament yarn is subjected to higher false twisting (depending on yarn fineness) action under the condition of underfeeding (depending on the ductility of parent yarn). The torque caused due to the high level of false twisting forces the filaments to follow a helical path at a certain angle (dependent on the magnitude of twist and denier per filament) to the longitudinal axis of the filament yarn.…”

“…The pattern of study in the pilot trials is similar to that adopted for the polyester yarn in the earlier study. 16 A brief review of trials along with their outcome has been given.…”

The Comfort Properties of Two Differential-Shrinkage Polyester Warp Knitted Fabrics

“…Fully drawn multifilament polyester yarns, with different linear densities, are produced by a single-head mechanical crimp texturing machine [13]. A high bulk polyester filament yarn was developed by fully drawn PET and POY [14].…”