Polyester yarn for industrial sewing thread and preparing method thereof

A preparing method for a polyester yarn for an industrial sewing thread, comprising:

• manufacturing a filament from a modified polyester through a series of processes composed of viscosity enhancing by a solid state polycondensation, melting, metering, extruding, cooling, oiling, stretching, heat setting and winding;
• wherein the modified polyester is a product of an esterification and a polycondensation of evenly mixed terephthalic acid, ethylene glycol, a tert-butyl branched dicarboxylic acid, a trimethylsilyl branched diol and a doped Sb2O3 powder;
• wherein the tert-butyl branched dicarboxylic acid is selected from the group consisting of 5-tert-butyl-1,3-benzoic acid, 2-tert-butyl-1,6-hexanedioic acid, 3-tert-butyl-1,6-hexanedioic acid and 2,5-di-tert-butyl-1,6-hexanedioic acid, and wherein the trimethylsilyl branched diol has a molecular formula of:
• wherein R stands for —CH2—, —CH(CH3)— or —C((CH3)2)—;
• wherein the doped Sb2O3 powder is obtained through a process of evenly mixing an Mx+solution and an Sb3+ solution at first, then dripping in a precipitant until a pH value of 9-10, and finally calcining a precipitate;
• wherein Mx+ is more than one ion selected from Mg2+, Ca2+, Ba2+ and Zn2+.