Abstract: A one-step spun composite DTY and preparation method thereof are provided. The bi-profiled fiber is manufactured with two types of modified polyester of different viscosities through the steps of melting, melt metering, composite extruding, cooling, oiling, drawing, heat setting and winding. Wherein those two modified polyesters have a molecular structure including terephthalic acid segments, ethylene glycol segments and branched diol segments, and the branched diol has a structural formula of here R1 and R2 are separately selected from the linear alkylene with 1-3 carbon atoms, R3 from the alkyl with 1-5 carbon atoms, and R4 from the alkyl with 2-5 carbon atoms. The obtained one-step spun composite DTY has an elastic shrinkage rate of no less than 35%. The method presented in this invention is involved in a simple and reasonable technological process for wide application range.

Abstract: A one-step spun composite DTY and preparation method thereof are provided. The bi-profiled fiber is manufactured with two types of modified polyester of different viscosities through the steps of melting, melt metering, composite extruding, cooling, oiling, drawing, heat setting and winding. Wherein those two modified polyesters have a molecular structure including terephthalic acid segments, ethylene glycol segments and branched diol segments, and the branched diol has a structural formula of here R1 and R2 are separately selected from the linear alkylene with 1-3 carbon atoms, R3 from the alkyl with 1-5 carbon atoms, and R4 from the alkyl with 2-5 carbon atoms. The obtained one-step spun composite DTY has an elastic shrinkage rate of no less than 35%. The method presented in this invention is involved in a simple and reasonable technological process for wide application range.

Abstract: A different shrinkage composite yarn and preparation method. The modified polyester is spun with a porous spinneret to produce a different shrinkage composite yarn, and the spinneret holes on the porous spinneret are arranged in an elliptical arrangement. The different shrinkage composite yarn is obtained by winding modified polyester POY yarn and FDY yarn, network recombining, and coiling them. The preparation method of modified polyester is as follows: terephthalic acid reacts with ethylene glycol to produce ethylene terephthalate. The modified polyester is obtained by the reaction of terephthalic acid with branched diol. The fiber of the invention has good properties and the deviation rate of fiber density. The CV value of breaking strength is ?4.0%, the CV value of elongation at break is ?8.0%, the CV value of coefficient of variation of coiling shrinkage is ?8.0%.

Abstract: A low chromatic aberration polyester different-shrinkage composite yarn is made of polyester POY yarn and polyester FDY composite yarn. The polyester POY yarn and polyester FDY yarn is obtained by spinning the polyester solution, the rupture strength of the low color polyester different-shrinkage composite yarn is ?1.9 cN/dtex, the elongation at break is 30.0±5.0%, the crimp shrinkage is 2.50±3.0%, the network degree is 20±5/m, the color difference ?E is less than 0.200. In the invention, the magnesium ethylene glycol is relatively mild, the thermal degradation coefficient is small, the oligomers in the polymerization process is reduced, and the oligomers in the dissolution process are further reduced, so that the appearance of stains and streaks reduces during the dyeing and post-processing heat setting of the polyester fiber, which ensures the fiber's leveling and rubbing fastness.

Abstract: A different shrinkage composite yarn and preparation method. The modified polyester is spun with a porous spinneret to produce a different shrinkage composite yarn, and the spinneret holes on the porous spinneret are arranged in an elliptical arrangement. The different shrinkage composite yarn is obtained by winding modified polyester POY yarn and FDY yarn, network recombining, and coiling them. The preparation method of modified polyester is as follows: terephthalic acid reacts with ethylene glycol to produce ethylene terephthalate. The modified polyester is obtained by the reaction of terephthalic acid with branched diol. The fiber of the invention has good properties and the deviation rate of fiber density. The CV value of breaking strength is ?4.0%, the CV value of elongation at break is ?8.0%, the CV value of coefficient of variation of coiling shrinkage is ?8.0%.

Abstract: A low chromatic aberration polyester different-shrinkage composite yarn is made of polyester POY yarn and polyester FDY composite yarn. The polyester POY yarn and polyester FDY yarn is obtained by spinning the polyester solution, the rupture strength of the low color polyester different-shrinkage composite yarn is ?1.9 cN/dtex, the elongation at break is 30.0±5.0%, the crimp shrinkage is 2.50±3.0%, the network degree is 20±5/m, the color difference ?E is less than 0.200. In the invention, the magnesium ethylene glycol is relatively mild, the thermal degradation coefficient is small, the oligomers in the polymerization process is reduced, and the oligomers in the dissolution process are further reduced, so that the appearance of stains and streaks reduces during the dyeing and post-processing heat setting of the polyester fiber, which ensures the fiber's leveling and rubbing fastness.