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Process for producing high viscosity polyester resin having low acetaldehyde content

The technology of a polyester resin and a production method is applied in the production field of high-viscosity polyester resin with low acetaldehyde content, can solve the problems such as difficulty in further reducing AA content, and achieves reliable production process, reduced acetaldehyde content, and improved product quality Effect

Inactive Publication Date: 2005-06-29
SINOPEC YIZHENG CHEM FIBER
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  • Abstract
  • Description
  • Claims
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Problems solved by technology

[0004] Since the lower the AA content is, the less likely it is to be removed, and the restriction of various factors in the solid-phase thickening process makes it difficult to further reduce the AA content in the final product. processing requirements form a very obvious contradiction
For existing liquid-phase polymerization and solid-phase viscosifying polyester equipment, this contradiction is even more prominent

Method used

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  • Process for producing high viscosity polyester resin having low acetaldehyde content
  • Process for producing high viscosity polyester resin having low acetaldehyde content

Examples

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Effect test

Embodiment 1

[0022] Using purified terephthalic acid PTA and ethylene glycol EG as the main raw materials, the conventional liquid phase polymerization process is used to produce low-viscosity polyester chips. The device adopts a five-pot process of two-stage esterification, two-stage pre-condensation and one-stage final polycondensation. Before the esterification reaction, germanium oxide containing a small amount of sodium salt is added according to the weight ratio of PTA to 100ppm, and the additive is mixed together with the main raw materials and then enters the esterification tank for reaction. Control the residence time of the esterification reaction to make the esterification rate 97%. Then, after the esterification reaction, phosphoric acid H was added according to the weight ratio of 750ppm to PTA 3 PO 4 , into the polycondensation tank for three-stage liquid-phase melt polymerization under negative pressure, pelletized and dried to obtain low-viscosity polyester chips with an i...

Embodiment 2

[0025] Using purified terephthalic acid PTA and ethylene glycol EG as the main raw materials, the conventional liquid phase polymerization process is used to produce low-viscosity polyester chips. The device adopts a three-pot process of one-stage esterification and two-stage polycondensation. Before the esterification reaction, germanium oxide containing a small amount of sodium salt is added according to the weight ratio of PTA to 200ppm, and the additive is mixed together with the main raw materials and then enters the esterification tank for reaction. Control the residence time of the esterification reaction to make the esterification rate 95%. Then, after the esterification reaction, phosphoric acid H was added according to the weight ratio of 900ppm to PTA 3 PO 4 , into the polycondensation tank for liquid-phase melt polymerization under negative pressure, pelletized and dried to obtain low-viscosity polyester chips with an intrinsic viscosity of 0.64dl / g. After detect...

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Abstract

The invention relates to a production method of high-viscosity polyester resin with relatively low acetaldehyde content. The invention focuses on the whole process of polyester production from liquid phase polymerization to solid phase polycondensation, and proposes targeted improvement measures and specific technical solutions for reducing AA: adjust the production formula in the liquid phase polymerization stage, add additives containing cobalt, sodium, and phosphorus, The reaction speed is accelerated, the degradation speed is slowed down, and the degradation by-products are significantly reduced. The AA content in the obtained low-viscosity chips is below 100-120ppm; in the SSP stage, through process optimization, the adjustment of the viscosity increase range of the resin during preheating and reaction process is realized. , which is more conducive to the removal of acetaldehyde. On the premise of ensuring other quality indicators, the AA content in the product is lower than 1.0ppm, which can meet the requirements of food packaging under the most stringent conditions. The technical scheme has reliable process and stable operation, and is especially suitable for producing polyester resin for mineral water packaging by adopting conventional SSP process.

Description

technical field [0001] The invention relates to a production method of high-viscosity polyester resin, especially a production method of high-viscosity polyester resin with relatively low acetaldehyde content. Background technique [0002] In the existing production technology of polyethylene terephthalate (PET, polyester for short), polyester resin with an intrinsic viscosity not exceeding 0.65 dl / g can be obtained through conventional liquid phase polymerization. The degree of polymerization of this type of resin PET is about 100, which is a low-viscosity polyester, and its main use is to make synthetic fibers. With the continuous expansion of polyester application fields, some beverage and food packaging materials are gradually using polyester products. Usually, the polyester product obtained by liquid phase polymerization must go through the process of "viscosification" to increase the intrinsic viscosity to 0.8dl / g, and the average degree of polymerization reaches more...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C08G63/181C08G63/78
Inventor 沈希军仲维权孙德广
Owner SINOPEC YIZHENG CHEM FIBER
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