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Continuous preparation method of semi-aromatic polyamide with low oligomer content and product thereof

A semi-aromatic and oligomer technology, which is applied in the field of continuous preparation of semi-aromatic polyamides, can solve the problems of low oligomer content and semi-aromatic polyamides, difficulty in meeting large production needs, unsatisfactory effects, and the like. Narrow molecular weight distribution, optimal mass transfer, and reduced oligomer content

Active Publication Date: 2021-04-02
ZHEJIANG NHU SPECIAL MATERIALS
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0009] It can be seen that the current technical solution for controlling the content of semi-aromatic polyamide oligomers from the source, such as the aforementioned CN104619777 A, has an unsatisfactory effect; and the method of removing oligomers through a simple solvent extraction method, because of high energy consumption, Low efficiency, difficult to meet the needs of industrialized mass production
In summary, there is still a lack of a method for the preparation of semi-aromatic polyamides with simple and efficient process, stable product quality and low oligomer content in this area.

Method used

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  • Continuous preparation method of semi-aromatic polyamide with low oligomer content and product thereof
  • Continuous preparation method of semi-aromatic polyamide with low oligomer content and product thereof
  • Continuous preparation method of semi-aromatic polyamide with low oligomer content and product thereof

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0100]According to the ratio of 0.95 of the initial feeding amine acid ratio, 4.57kg / h (27.5mol / h) terephthalic acid, 3.29kg / h (22.5mol / h) adipic acid, 5.52kg / h (47.5mol / h) Hexamethylenediamine, 0.05kg / h of 20wt% sodium hypophosphite aqueous solution and 5.72kg / h of water are put into the beating kettle 9, and continuously beating at 80°C to form a slurry. The slurry is transported by pump 10 to multi-stage stirring dissolution tank 14 and heated to 150° C. to dissolve into salt with the steam generated in the dehydration process. According to the composition of the dibasic acid in the salt solution detected by the on-line Raman spectrum 18, the amount of the aliphatic dibasic acid is adjusted by using molten adipic acid through the metering pump 23, so that the aromatic dibasic acid and the aliphatic dibasic acid in the salt-forming kettle 19 are dissolved. The molar ratio of basic acid was stable at 55:45. After the composition of the above-mentioned salt solution is detect...

Embodiment 2

[0108] The prepolymer sprayed under reduced pressure in the flash reactor is dried in the spray tower by 130°C nitrogen circulation air containing dichloromethane vapor to obtain the prepolymer. The volume flow ratio of the extractant vapor to nitrogen is 1:80. Other steps and processes and implementation Example 1 is exactly the same, and the semi-aromatic polyamide product of about 12.2kg / h is finally obtained.

Embodiment 3

[0110] The prepolymer sprayed under reduced pressure in the flash reactor is dried in the spray tower by 100°C nitrogen circulation air containing chloroform vapor to obtain the prepolymer. The volume flow ratio of the extractant vapor to nitrogen is 1:40. Other steps and processes and implementation Example 1 is exactly the same, and the semi-aromatic polyamide product of about 11.8kg / h is finally obtained.

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Abstract

The invention discloses a continuous preparation method of semi-aromatic polyamide with low oligomer content, which comprises the following steps: (a) by using water as a solvent and diamine and binary as initial feeding materials, adding a catalyst, pulping, heating to dissolve, neutralizing and salifying; (b) dehydrating and concentrating the salt solution obtained after neutralizing and salifying, detecting the content of diamine in the steam condensate, adjusting the molar ratio of amine to acid to be greater than 1.0, and then carrying out a prepolymerization reaction; and (c) sequentially carrying out flash evaporation spraying and circulating air drying containing extraction agent steam on the pre-polymerization reaction liquid, melting and tackifying by an extruder, and carrying out underwater pelletizing to obtain semi-aromatic polyamide particles with low oligomer content. The extractant vapor is selected from dichloromethane and / or trichloromethane vapor. The preparation method disclosed by the invention is simple in process and short in production period; and the content of oligomers in the semi-aromatic polyamide product is remarkably reduced and is lower than 0.85%, the molecular weight distribution is narrow, no pollution is caused to a mold during molding processing, and the semi-aromatic polyamide product can be widely applied to the fields of electronics, electrics, automobiles and the like.

Description

technical field [0001] The invention relates to the technical field of semi-aromatic polyamides, in particular to a method for continuously preparing semi-aromatic polyamides with low oligomer content and products thereof. Background technique [0002] Polyamide refers to a class of polymers containing repeated amide groups in the main chain of the molecule. Because of its excellent wear resistance, good mechanical properties and chemical resistance, it has been widely used in textiles since its industrialization in 1939. Fiber, electrical and electronic and automotive fields. However, as traditional general-purpose engineering plastics, such as nylon 6 and nylon 66, defects such as high water absorption, poor dimensional stability, and insufficient heat resistance are increasingly exposed, which limits their application in high-tech fields. Therefore, it is urgent to develop polyamides with excellent comprehensive properties. resin. [0003] Semi-aromatic polyamide is a k...

Claims

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Application Information

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IPC IPC(8): C08G69/26C08G69/28
CPCC08G69/265C08G69/28
Inventor 周贵阳熊章星邓杭军朱丹琪洪文刚吴笑笑
Owner ZHEJIANG NHU SPECIAL MATERIALS
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