Method for preparing modified polytrimethylene terephthalate

Abstract

The invention relates to a method for preparing modified polytrimethylene terephthalate. In esterification reaction, one or combination of more of straight-chain aliphatic dicarboxylic acid with the carbon number between 3 and 20, 1,4-cyclohexanedicarboxylic acid, straight-chain aliphatic diol with the carbon number between 4 and 20 and 1,4-cyclohexanedimethanol is taken as a third monomer; the use amount of the third monomer is 0.3 to 6.0 weight percent of the total weight of initial reaction raw materials; polyethylene glycol with the average molecular weight between 200 and 2,000, serving as a flexible chain segment, is added into the polymerization reaction, and the addition amount is 0.5 to 8.5 weight percent of the total weight of the initial reaction raw materials; and the modifiedpolytrimethylene terephthalate is produced by the conventional polyester production process. The modified polyester chips prepared by the method have good spinnability and excellent crystallization capacity; in the spinning process, fibers are fully crystallized, so the stable crystallization rate is formed; when the fibers are heated and subjected to external stress, the crystallization rate of the stress parts of the fibers is stable, and the defect that PTT polyester fiber fabrics are susceptible to external force and high temperature loss can be effectively improved.

Description

technical field [0001] The invention relates to a preparation method of polyester, in particular to a preparation method of modified poly-1,3-trimethylene terephthalate. Background technique [0002] Polypropylene terephthalate (PTT polyester) is a new type of organic polymer aromatic polyester product belonging to the same polymer series as PET and PBT. It is based on purified terephthalic acid (PTA) and 1,3-Propanediol (PDO) is the starting material, which is obtained through esterification and polycondensation. [0003] The successful development of PTT has further enriched the series of chemical fiber products. First of all, unlike the almost linear macromolecular conformation of PET polyester, the molecular conformation of PTT polymer is helical. The helical molecular conformation will allow the PTT fiber to be highly "expanded", so that the fiber has good elasticity; secondly, the glass transition temperature of PTT polyester is low, and it is easy to produce low-tem...

AI Technical Summary

Problems solved by technology

Small changes in spinning conditions can cause changes in the internal structure of PTT fibers, resulting in different fiber uniformity, which brings great difficulties to the adjustment of the spinning process

In addition, in the prior art, in order to prevent melt degradation, the spinning of PTT polyester is usually carried out at a lower temperature, so that the fiber crystallization is insufficient during winding and stretching to form color stripes or color differences

Although the resulting fabric has a good feel and texture, in the process of sizing, weaving, printing and dyeing, and even the finished garment, there is a phenomenon that the fiber recrystallizes under the action of tension when it is stretched by an external force. It is easy to form color difference and color stripes, and it will cause scratches and white stripes on the finished garments, forming irreversible flaws

These defects have always limited the application of PTT polyester fiber, directly leading to difficulties in PTT fabrics and clothing care.

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