Abstract: A method for preparing high shrinkage PTT copolyester, includes adding starting raw materials into a reaction kettle and adding an esterification catalyst to carry out esterification reaction at 220° C.-260° C. under 0.05-0.30 MPa and completing the reaction when there being no water produced; and adding polymerization catalyst into the reaction system and carrying out the polymerization reaction at 240° C.-280° C. to get polytrimethylene terephthalate. The starting raw materials consists of 1,3-propylene glycol, terephtalic acid, a third monomer, a forth monomer and a fifth monomer. Polytrimethylene terephthalate prepared by the invention shows good spinning behaviour, of which the crystallization speed is noticeably lower than that of conventional polytrimethylene terephthalate, thus, fibers made of them has high boiling water shrinkage rate and ideal shrink property.

Abstract: A method is disclosed herein for the preparation of modified poly (1,3-propanediol terephthalate). The method comprises adding linear polyester with average molecular weight of 800˜3000 and polyethylene glycol with average molecular weight of 200˜2000 into polymerization monomers before polymerization reaction, wherein the linear polyester is a polymer obtained by reaction of C3 ˜C10 straight chain aliphatic dicarboxylic acid or 1,4-cyclohexane diformic acid with C2 ˜C10 straight chain aliphatic diol or 1,4-cyclohexane diformic acid; the linear polyester is 0.5%˜6% of the mass of polymerization monomers; the polyethylene glycol is 0.5%˜8.5% of the mass of polymerization monomers.

Abstract: A method is disclosed herein for the preparation of polytrimethylene terephthalate with sustained-release crystallinity. The method reduces crystallization rate and crystallinity-saturation ratio of polytrimethylene terephthalate during spinning, through addition of a third monomer during the esterification reaction step. The third monomer acts as copolymerization component generating intermolecular steric hindrance; the identity of which selects from one or more as combinations of the following: trimellitic anhydride, non-para aromatic dicarboxylic acid, C4-C10 aliphatic dicarboxylic acid having branched chains or naphthenic group and C3-C10 aliphatic dihydric alcohol having branched chains or naphthenic group, the molar ratio of carboxyl to hydroxyl is 1:1.16˜1.85, with the third monomer constituting 0.5˜6.5% of the total weight of the beginning raw materials.

Abstract: A method is disclosed herein for the preparation of modified poly (1,3-propanediol terephthalate). The method comprises adding linear polyester with average molecular weight of 800˜3000 and polyethylene glycol with average molecular weight of 200˜2000 into polymerization monomers before polymerization reaction, wherein the linear polyester is a polymer obtained by reaction of C3˜C10 straight chain aliphatic dicarboxylic acid or 1,4-cyclohexane diformic acid with C2˜C10 straight chain aliphatic diol or 1,4-cyclohexane dimethanol; the linear polyester is 0.5%˜6% of the mass of polymerization monomers; the polyethylene glycol is 0.5%˜8.5% of the mass of polymerization monomerss.

Abstract: A method for preparing high shrinkage PTT copolyester, comprising: adding starting raw materials into a reaction kettle and adding an esterification catalyst to carry out esterification reaction at 220° C.˜260° C. under 0.05˜0.30 MPa and completing the reaction when there being no water produced: adding polymerization catalyst into the reaction system and carrying out the polymerization reaction at 240° C.˜280°C. to get polytrimethylene terephthalate. The starting raw materials consists of 1,3-propylene glycol, terephtalic acid, a third monomer, a fourth monomer and a fifth monomer.