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Method of recovering polyimide raw material by hydrolyzing polyimide waste thin film by ammonia water

A polyimide and film technology, which is applied in the field of polyimide raw material recovery from waste polyimide film by ammonia hydrolysis, can solve problems such as poor product quality and achieve the effect of high purity

Inactive Publication Date: 2014-02-05
上海固创化工新材料有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Because this method uses a strong base as a hydrolyzing agent, the alkali metal ions remaining in the pyromellitic dianhydride will carbonize the product, resulting in black spots on the product, resulting in poor product quality

Method used

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  • Method of recovering polyimide raw material by hydrolyzing polyimide waste thin film by ammonia water
  • Method of recovering polyimide raw material by hydrolyzing polyimide waste thin film by ammonia water
  • Method of recovering polyimide raw material by hydrolyzing polyimide waste thin film by ammonia water

Examples

Experimental program
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Effect test

Embodiment 1

[0025] 2000g of discarded polyimide film that has been crushed into a length of 7mm is put into 37000ml of ammoniacal liquor with a concentration of 27% by weight, in a stainless steel 316L hydrolysis kettle at a temperature of 200°C and a pressure of 1.4MPa for 3 hours of hydrolysis reaction, cooling, filtering, and Separate the product pyromellitic acid and 4,4'-diaminodiphenyl ether, filter the obtained 4,4'-diaminodiphenyl ether solid, wash with water three times, recrystallize with alcohol, cool to below 40°C, filter , the obtained solid was dried at a temperature of 120°C for 3 hours, then sublimated in a sublimation kettle at a temperature of 190-192°C and a pressure of 0.2-0.3 mmHg, and the purity of the solid product of 4,4'-diaminodiphenyl ether obtained by sublimation was 99.9 %, melting point 192-193°C. The yield is 955g (theoretical yield is 960g).

[0026] The mother liquor obtained by filtration contains pyromellitic acid and unreacted ammonia water, and the hy...

Embodiment 2

[0028] In addition to the input concentration of 3300ml of ammonia water of 30% by weight, pyromellitic acid was dehydrated at a temperature of 260°C for 2 hours, the length of the discarded polyimide film was 10mm, and the sublimation temperature of pyromellitic dianhydride was 260°C. Anhydride yield is except that 1030g, other operation steps and product quality are the same as embodiment 1.

Embodiment 3

[0030] Except that the length of polyimide waste film is 5mm, pyromellitic acid is dehydrated at 250°C for 3 hours, the sublimation temperature of pyromellitic dianhydride is 250°C, and the yield of pyromellitic dianhydride is 1010g, other operations Step and product quality index are the same with embodiment 1.

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Abstract

The invention discloses a method of recovering a polyimide raw material by hydrolyzing a polyimide waste thin film by ammonia water, and relates to ammonia water hydrolysis of a waste polypyromellitimide thin film and a recycling method of a hydrolyzed product pyromellitic acid. The concentration of ammonia water is 25-30wt%, the content of the waste thin film in the ammonia water is 20wt%, and the sublimation conditions of 4, 4'-diaminodiphenyl ether are that the temperature is 190-192 DEG C and the pressure is 0.2-0.3mmHg. The purity of the product is 99.9%, and the melting point is 192-193 DEG C. The pyromellitic acid is dehydrated for 2-3 hours at 250-260 DEG C at 100mmHg to remove about 10wt% of water, so that almost part of the pyromellitic acid is converted into pyromellitic dianhydride, wherein the sublimation conditions of the pyromellitic dianhydride are that the temperature is 250-260 DEG C, and the pressure is 0.2-0.3mmHg. The product is free from small black points, the purity is over 99.5%, and the melting point is 286-287 DEG C.

Description

1. Technical field [0001] The invention relates to a method for recycling polyimide raw materials by hydrolyzing polyimide waste films with ammonia water, more precisely, it relates to a method for hydrolyzing waste polyimide films with ammonia water, and the hydrolysis products pyromellitic acid and 4,4' - recovery method of diaminodiphenyl ether. 2. Background technology [0002] With the development of my country's high-tech industry, the number of polyamideimide films for both military and civilian purposes is increasing. At present, the national consumption of polyimide film is 3500-4000 tons per year, and the waste polyimide film produced is about 400 tons per year. The waste polyimide film comes from the trimming of the production film and the film discarded by the maintenance of electrical equipment Wait. As we all know, polypyromellitic imide, which is completely dehydrated and cyclized, is a polymer material with high heat resistance and excellent chemical resist...

Claims

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Application Information

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IPC IPC(8): C07C63/313C07C51/00C07C217/90C07C213/00
CPCC07C51/00C07C213/02C07D493/04C07C63/313C07C217/90
Inventor 刘少华唐泉清
Owner 上海固创化工新材料有限公司
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