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Depolymerization and recovery method of high temperature resistant nylon poly-para-phenylene diformyl hexane diamine

A technology of polyhexamethylene terephthalamide and polyhexamethylene terephthalamide, which is applied in the field of high temperature resistant nylon polyhexamethylene terephthalamide depolymerization, and can solve the problem of no literature on PA6T recycling. or patent issues

Inactive Publication Date: 2009-05-06
NINGBO UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0004] However, although there are many companies producing PA6T, such as DuPont, etc., there is no literature or patent on the recovery of PA6T so far.

Method used

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  • Depolymerization and recovery method of high temperature resistant nylon poly-para-phenylene diformyl hexane diamine
  • Depolymerization and recovery method of high temperature resistant nylon poly-para-phenylene diformyl hexane diamine

Examples

Experimental program
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Effect test

Embodiment 1

[0018] Add 500Kg solid sodium hydroxide and 1000Kg water into the reaction kettle, stir and dissolve, then add the crushed waste nylon PA6T. React under the condition of 0.6MPa for 5 to 8 hours to complete the reaction and obtain an alkaline hydrolyzate; then filter the alkaline hydrolyzate through a coarse filter to remove solid residues, add benzene / n-butanol mixed extractant after cooling, and the extractant The molar ratio is 2:1, the crude hexamethylenediamine is extracted, the extract is subjected to fractional distillation in the rectification tower, and the distilled organic solvent is compounded with a fresh solvent and continues to be used as an extractant in the next production cycle; After extracting solvent with boiling point, carry out rectification under reduced pressure, control the collection temperature of hexamethylenediamine fraction to be lower than 170°C, and obtain hexamethylenediamine with a purity greater than 99.1%; the aforementioned raffinate is sodi...

Embodiment 2

[0020] Add 250Kg solid sodium hydroxide and 1000Kg water into the reaction kettle, stir and dissolve, then add the crushed waste nylon PA6T, the molar ratio of sodium hydroxide to PA6T is 2.5:1, stir, and keep the temperature at 70-90°C and the pressure at 0.1~ React under the condition of 0.6MPa for 5 to 8 hours to complete the reaction and obtain an alkaline hydrolyzate; then filter the alkaline hydrolyzate through a coarse filter to remove solid residues, add benzene / n-butanol mixed extractant after cooling, and the extractant The molar ratio is 1:1, the crude hexamethylenediamine is extracted, and the extract is subjected to fractional distillation in the rectification tower, and the distilled organic solvent is compounded with fresh solvent and continues to be used as the extraction agent in the next production cycle; Carry out vacuum rectification after the extraction solvent with boiling point, control the collection temperature of hexamethylenediamine fraction to be low...

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Abstract

The invention relates to a method for depolymerizing and recovering high temperature resistant nylon poly(p-phenylene-hexamethylenediamine), which is characterized by comprising the following steps in turn: sodium hydroxide and water are added into a reaction kettle, dissolved, added with crushed nylon PA5T, and subjected to depolymerizaton to obtain a alkali-hydrolyzable liquid; the alkali-hydrolyzable liquid passes through a filter, enters a workshop section of separation and extraction, and is extracted and separated by an arene / alcohol mixed extractant to obtain coarse hexamethylenediamine extract and terephthalic acid sodium salt faffinate; the coarse hexamethylenediamine extract is subjected to distillation and rectification to respectively obtain arene / alcohol / -hexamethylenediamine and arene / alcohol, an organic solvent which is distilled off is replenished with a fresh solvent and can be reused as an extractant, and refined hexamethylenediamine can be obtained after removal of a extracting solvent with low boiling point by means of distillation, and decompression and rectification; and the terephthalic acid sodium salt solution is subjected to decolorization, neutralization, filtration and separation to obtain a terephthalic acid, and a refined terephthalic acid is obtained after water scrubbing and drying of the terephthalic acid. The method has reasonable and practical technology, can reutilize the solvent, reduces the recovery cost, simultaneously reduces environmental pollution, and improves the resource utilization rate.

Description

technical field [0001] The invention relates to a method for depolymerizing high-temperature-resistant nylon polyhexamethylene terephthalamide (PA6T), in particular to a method for depolymerizing high-temperature-resistant nylon PA6T suitable for large-scale industrial production. Background technique [0002] Nylon (PA) has excellent mechanical properties, wear resistance, self-lubrication, oil resistance, and stability, and has become one of the most widely used plastics at home and abroad, ranking first among the five engineering plastics. High temperature resistant PA6T is a resin formed by polycondensation of terephthalic acid and hexamethylenediamine. It has characteristics that other nylons do not have, especially in high temperature resistance. In recent years, with its continuous application in many fields, its products are difficult to dispose of after use, which not only causes waste, but also pollutes the environment. Therefore, recycling high-temperature resista...

Claims

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Application Information

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IPC IPC(8): C08J11/16C08J11/28C08L77/06
CPCY02W30/62
Inventor 魏丹毅张振民王邃孙利民郭智勇
Owner NINGBO UNIV
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