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Method for preparing PET (polyethylene glycol terephthalate) by composite catalyst

A technology of polyethylene terephthalate and composite catalyst is applied in the field of synthesizing polyethylene terephthalate, and can solve the problems of poor thermal stability, yellow color, low catalytic efficiency and the like of PET products

Active Publication Date: 2017-06-13
BEIJING INST OF CLOTHING TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0004] Antimony catalysts mainly include antimony trioxide, antimony acetate and antimony glycol. Although the technology of antimony catalysts is relatively mature, it has the advantages of moderate catalytic activity, less side reactions, and low price. However, Sb catalysts are widely used at the same time. There are also some obvious disadvantages: because antimony compounds themselves have certain toxicity and coexist with highly toxic arsenic in nature, the application of Sb catalysts is limited to a certain extent.
[0007] However, the titanium-based catalyst itself has poor stability and is easy to hydrolyze, resulting in poor thermal stability, yellow color, and low catalytic efficiency of PET products produced with it, and has not been used on a large scale.

Method used

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  • Method for preparing PET (polyethylene glycol terephthalate) by composite catalyst
  • Method for preparing PET (polyethylene glycol terephthalate) by composite catalyst

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Effect test

experiment example 9～13

[0049] Therefore, the present invention chooses to add the composite catalyst before the esterification reaction or in the esterification reaction stage.

[0050]The inventor also found that the addition of the composite catalyst had an important impact on the esterification reaction time and the polycondensation reaction time in the synthesis of polyethylene terephthalate through a large amount of research. The shorter the time of esterification reaction, and along with the increase of composite catalyst usage amount, polycondensation reaction time shortens first and then increases, and the consumption of composite catalyst is 19 μ g / g (this consumption is based on the weight of terephthalic acid, with titanium in it When the weight of the element), the polycondensation reaction time is the shortest. (see Experimental Examples 14-20 for details)

experiment example 14～20

[0051] Therefore, the present invention selects the consumption of composite catalyst to be (5~50) μ g / g, preferably (9~40) μ g / g, more preferably (15~30) μ g / g, as 9.5 μ g / g, 19 μ g / g g, 28.5 μg / g and 38 μg / g, particularly preferably 19 μg / g, wherein the amount is based on the weight of terephthalic acid and calculated by the weight of titanium element therein.

[0052] In a preferred embodiment of the present invention, the method comprises the following steps:

[0053] Step 1, esterification reaction: add terephthalic acid, ethylene glycol and composite catalyst into the polymerization kettle, mix, preferably raise the temperature, add ethylene glycol and antioxidant, preferably, also add heat stabilizer, and continue mixing;

[0054] Step 2, polycondensation reaction: first make the inside of the reaction kettle in a low vacuum state, and then enter a high vacuum state after a period of time, then raise the temperature in the kettle, and keep stirring until the reaction en...

Embodiment 1

[0087] The preparation of embodiment 1 composite catalyst

[0088] Add 2.23mL of tetraethyl silicate into ethylene glycol, and optionally stir to obtain a diol solution of tetraethyl silicate;

[0089] 1.07 mL of phenylphosphonic acid was added to the above diol solution of tetraethyl silicate, optionally stirred, and then added into 20.47 mL of tetrabutyl titanate to obtain a composite catalyst.

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Abstract

The invention discloses a method for preparing PET (polyethylene glycol terephthalate) by a composite catalyst. The method is characterized in that when terephthalic acid and ethylene glycol are used as raw materials to prepare the PET, the composite catalyst containing tetrabutyl titanate, tetraethl silicate and phenylphosphonic acid is used for catalyzing, so as to obtain PET with high molecular weight, narrow molecular weight distribution and good mechanical property and heat stability; the catalyzing activity of the composite catalyst is 17 or more times of the activity of an antimony based catalyst.

Description

technical field [0001] The invention relates to a synthesis process, in particular to a method for synthesizing polyethylene terephthalate. Background technique [0002] Polyethylene terephthalate (PET) is the product of terephthalic acid (PTA) and ethylene glycol (EG) through esterification and polycondensation reactions. It is the largest output and variety of polyester products in my country. A class of synthetic materials used in many fields such as fibers, films, and bottles. [0003] In recent years, with countries and regions such as Europe and the United States, the concept of "green fiber" has been proposed one after another, and environmentally friendly green fiber textiles have become the trend of international development. This trend of green fiber textiles woven from raw materials that are harmless to human health and the environment has threatened the export of my country's textiles. This is because the catalysts commonly used to synthesize PET are antimony-ba...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C08G63/85C08G63/87C08G63/183
CPCC08G63/183C08G63/85C08G63/87
Inventor 王锐张文娟姜虹宇朱志国张秀芹董振峰刘继广
Owner BEIJING INST OF CLOTHING TECH
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