1, 2-propanediol copolyester polyterephthalate with high 1, 2-propanediol content and preparation method thereof

Abstract

The invention relates to 1, 2-propanediol copolyester polyterephthalate with high 1, 2-propanediol content and a preparation method thereof. The method comprises the following steps of: reacting a dimethyl terephthalate monomer with linear glycol under the catalysis of an ester exchange catalyst to obtain bilinear glycol ester terephthalate with complete ester exchange; reacting the dimethyl terephthalate monomer with a 1, 2-propanediol monomer under the catalysis of an ester exchange catalyst and a polycondensation catalyst; mixing the mixture and the bilinear glycol ester terephthalate; andperforming polycondensation under reduced pressure to obtain a sample. Compared with the prior art, the method has the advantage that: the problem of low copolyester content due to large reaction steric hindrance and low activity of 1, 2-propanediol in the process of reacting the 1, 2-propanediol and the linear glycol with terephthalic acid to form the copolyester is solved; and the obtained product has the advantages of meeting a high-temperature using environment along with stable forming size and high transparency.

Description

technical field [0001] The invention relates to a polyester and a preparation method thereof, in particular to a polyterephthalic acid 1,2-propylene glycol copolyester with high 1,2-propanediol content and a preparation method thereof. Background technique [0002] Polypropylene terephthalate (PTT) was first synthesized in 1941 by Whinfield and Dickson of the British Calico Printing and Dyeing Workers Association (CPA). However, it was not until the 1990s that the US Shell Company developed low-cost 1,3-propanediol, and the industrial production of PTT began. PTT is a new type of polyester with excellent performance. In addition to the chemical resistance of PET fiber, it also has excellent elastic recovery and recovery rate. Its inherent stain resistance, antistatic property and color fastness are also very good. , has a wide range of uses in fiber, manufacturing containers, films, etc. [0003] 1,2-propanediol is an isomer of 1,3-propanediol and has a similar structure t...

AI Technical Summary

Problems solved by technology

[0004] However, the side chain methyl group on the 1,2-propanediol molecule increases the T of poly-1,2-propanediol ester g At the same time, it also reduces the reactivity of secondary hydroxyl groups, so it is difficult to polymerize with dibasic acids to obtain high molecular weight polymers

Propose 1 in U.S. Patent 4093603, the polyester of 2-propanediol and terephthalic acid is basically useless, because there are both primary hydroxyl groups and secondary hydroxyl groups on it, and the reactivity of secondary hydroxyl groups in the polycondensation process is lower than that of The primary hydroxyl group is much weaker, so it is difficult to obtain high molecular weight polyester from 1,2-propanediol with secondary hydroxyl groups

[0005] When utilizing 1,2-propanediol to carry out copolymerization with linear diols (such as ethylene glycol, butanediol, etc.) Hydroxyl, high reactivity, when the content of linear diol is less, it is easy to polymerize first and be located inside the polyester molecular chain, and then 1,2-propanediol is connected to the two ends of the molecular chain to form a capping effect, which also cannot be obtained High molecular weight polyester; when the content of linear diol is high, a large part of 1,2-propanediol, which accounts for less content, is extracted in the polycondensation stage, so the content in the final copolyester product is much lower than that in the raw material , no poly(trimethylene terephthalate) copolyester with high 1,2-propanediol content was obtained

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