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Thermotropic liquid crystal polyester and preparation method thereof

A liquid crystal polyester, thermotropic technology, applied in the field of materials, can solve problems such as poor exhaust, improper molding conditions, easy foaming of thermotropic liquid crystal polyester, etc., to achieve excellent mechanical properties and reduce clogging effects

Active Publication Date: 2020-04-10
JIANGMEN DENGZHONGTAI ENG PLASTICS CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

In addition, there are some other factors, such as improper molding conditions leading to air entrapment, unreasonable mold design and poor exhaust, etc.
Usually, in production, by strictly controlling the amount of aliphatic anhydride and the amount of monomer during the acetylation reaction, the incomplete acetylation of the monomer or the blackening of the thermotropic liquid crystal polyester can be avoided, but it still cannot completely solve the problem of thermal The problem of easy foaming of nontropic liquid crystal polyester in high temperature reflow soldering process

Method used

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  • Thermotropic liquid crystal polyester and preparation method thereof
  • Thermotropic liquid crystal polyester and preparation method thereof
  • Thermotropic liquid crystal polyester and preparation method thereof

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0033] Add 2760g (20mol) p-hydroxybenzoic acid, 1860g (10mol) 4,4-diphenol, 415g (2.5mol) isophthalic acid, 1245g (7.5mol) terephthalic acid, 8160g ( 80mol) of acetic anhydride, 5g of potassium acetate, nitrogen purging to replace the air in the reaction kettle, then heat up to 140°C for acetylation reaction, while rectifying for 2 hours, during which the distillate gas with a boiling point lower than 120°C is discharged, and then after condensation Afterwards, collect and weigh to obtain 2550 g of by-product acetic acid, and keep the amount of acetic anhydride in the reaction system to be about 50% of the total amount of acetic anhydride and acetic acid. Keep the temperature in the kettle at 150°C, slowly evacuate to 100pa, drain and condense the remaining acetic anhydride in the system, and the collected acetic anhydride can be reused. Continue to heat up to 340°C, during which the by-product acetic acid produced by the polymerization is discharged in time, and finally vacuu...

Embodiment 2

[0035] Add 3450g (25mol) p-hydroxybenzoic acid to 20 liters of reactor, 940g (5mol) 2-hydroxy-6-naphthoic acid, 550g (5mol) hydroquinone, 830g (5mol) terephthalic acid, 8160g (80mol) Acetic anhydride, 5g N-methylimidazole, after purging and displacing the air in the reactor with nitrogen, the temperature was raised to 150°C for acetylation reaction, while rectification was carried out for 2.5 hours, during which the distillate gas with a boiling point lower than 120°C was discharged, and then after condensation Afterwards, collect and weigh to obtain 1800 g of by-product acetic acid, and keep the amount of acetic anhydride in the reaction system to be about 80% of the total amount of acetic anhydride and acetic acid. Keep the temperature in the kettle at 150°C, slowly evacuate to 50pa, discharge and condense the remaining acetic anhydride in the system, and the collected acetic anhydride can be reused. Continue to heat up to 340°C, during which the by-product acetic acid produ...

Embodiment 3

[0037]Add 4140g (30mol) p-hydroxybenzoic acid, 1880g (10mol) 2-hydroxyl-6-naphthoic acid, 6120g (60mol) acetic anhydride, 5gN-methylimidazole to the 20 liter reactor, after nitrogen purging replaces the air in the reactor , heated up to 150°C, carried out acetylation reaction, and rectified for 2.5 hours at the same time, during which the fraction gas with a boiling point lower than 120°C was discharged, and then collected and weighed after condensation to obtain 1820g of by-product acetic acid, keeping the content of acetic anhydride in the reaction system The amount is about 80% of the total amount of acetic anhydride and acetic acid. Keep the temperature in the kettle at 150°C, slowly evacuate to 100pa, drain and condense the remaining acetic anhydride in the system, and the collected acetic anhydride can be reused. Continue to raise the temperature to 320°C, during which the by-product acetic acid produced by the polymerization is discharged in time, and finally vacuumize ...

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Abstract

The invention belongs to the field of materials, and discloses thermotropic liquid crystal polyester which is obtained by reaction of a monomer, aliphatic anhydride and a catalyst; the monomer comprises at least one of HO-Ar-COOH (I), HO-Ar-OH (II) and HOOC-Ar-COOH (III); Ar is at least one of phenyl, biphenyl, naphthyl, anthryl or phenanthrene; the amount of substance of aliphatic anhydride is 1.3-3 times of the amount of substance of hydroxyl in the monomer. In the acetylation reaction process, by-product fatty acid is removed, and the amount of substance of aliphatic anhydride is strictly controlled, so that the acetylation reaction is more complete, blockage caused by monomer volatilization is reduced, the prepared thermotropic liquid crystal polyester does not turn black and does notbubble in the reflow soldering process, and the mechanical property is excellent.

Description

technical field [0001] The invention belongs to the field of materials, in particular to a thermotropic liquid crystal polyester and a preparation method thereof. Background technique [0002] Thermotropic liquid crystal polyesters are widely used in aviation, electronics, electrical appliances, automobiles, machinery, chemicals, fibers, optics and other fields due to their excellent properties such as high fluidity, high heat resistance, low shrinkage, and low dielectric properties. , especially in the electrical and electronic industry, the most widely used. However, when electronic components are prepared by using thermotropic liquid crystal polyester, when heated in an infrared heating device, they are subjected to a high-temperature reflow soldering process, which is prone to foaming and seriously affects the quality of the product. [0003] There are many reasons for the thermotropic liquid crystal polyester to foam during the reflow process, mainly due to the small m...

Claims

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Application Information

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IPC IPC(8): C08G63/60C08G63/06C08G63/78C08L67/03C08L67/04C09K19/38
CPCC08G63/605C08G63/065C08G63/78C08L67/03C08L67/04C09K19/3809C08G2250/00C08L2203/20
Inventor 曾建平金良文梁咏华郑红专梁洪辉
Owner JIANGMEN DENGZHONGTAI ENG PLASTICS CO LTD
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