Melt-spinning of finer polyester micro filaments, reduces melt viscosity as a function of titer

摘要

Fine (below 0.7 dtex) polyester micro filaments are spun from a low-viscosity, polyester melt. The melt viscosity is related to their titer. It is reduced below a corresponding melt quality for polyester fiber spinning of 1.60 to 1.65. Fine (below 0.7 dtex) polyester micro filaments are spun from a low-viscosity, polyester melt. The melt viscosity is related to their titer. It is reduced below a corresponding melt quality for polyester fiber spinning of 1.60 to 1.65. The micro filament titer is related to the reduced relative solvent viscosity by equation (1). eta = 0.1052 ln X + 1.649 (1) Where X is the DTY titer in dtex and the spinning velocity is 2500 m/min +/- 10%. Acceptable spinning reliability at a defined filament titer is achieved with the solvent viscosity varying over the range +/- 0.05%. The viscosity is reduced by adding viscosity-control additive(s), and homogenizing. Titers of the spun filaments range between 0.1 - 0.7 dtex, 0.1 - 0.2 dtex or up to 0.35 dtex. An Independent claim is included for corresponding polyester micro filaments of up to 0.7 dtex. They have a gray scale dyeing uniformity of 4.0-5.0 and a DELTA E value of less than 1.