Three-phase hydrolytic polymerization process for nylon 6

A hydrolysis polymerization, three-stage technology, applied in the field of nylon 6 production process, can solve problems such as affecting the polymerization process, pressure fluctuations, and rising manufacturing costs, so as to improve product quality, stabilize liquid level, and improve controllability. Effect

Inactive Publication Date: 2016-04-20
JIANGSU HONGSHENG NEW MATERIAL
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0007] At present, the maximum negative pressure capacity of the conventional pre-polymerization reactor is about 3 Bar. If a pre-polymerization reactor with higher negative pressure capacity is required, the manufacturing cost will increase
The initial stage of hydrolysis polymerization of fresh caprolactam is mainly hydrolysis ring-opening and addition reaction, in which the addition reaction is an exothermic reaction, but the two-step reaction of hydrolysis and addition is interspersed in the early stage, and the addition reaction is carried out one hour before the polymerization reaction It is also the most violent, because the addition reaction exothermic is very easy to cause pressure fluctuations, which will cause the instability of the pre-polymerization liquid level, affect the polymerization process, and finally affect the quality of the product

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0019] A kind of nylon 6 three-stage hydrolysis polymerization process comprises the following steps:

[0020] a. Add 4600 kilograms of reaction materials per hour to the composite tank and mix evenly. The reaction materials include fresh caprolactam, deoxygenated desalted water and terephthalic acid, wherein the quality of deoxygenated desalted water is 1.5% of the quality of fresh caprolactam, The quality of terephthalic acid is 1‰ of the quality of fresh caprolactam;

[0021] b. After fresh caprolactam, deoxygenated desalted water and terephthalic acid are mixed evenly in the compounding tank, the pump pressurizes to 6.5 Bar and the temperature is quickly heated to 180°C by the preheater. After heating, the mixed material is sent to the pre-heater The pre-polymerization reaction (i.e. the hydrolysis ring-opening and addition reaction of fresh caprolactam) is carried out in the polymerization reactor. in 2 hours;

[0022] c. After the material has undergone high temperatur...

Embodiment 2

[0026] A kind of nylon 6 three-stage hydrolysis polymerization process comprises the following steps:

[0027] a, 4600 kilograms of reaction materials are added into the composite tank per hour and mixed evenly. The reaction materials include fresh caprolactam, deoxygenated desalted water and terephthalic acid, wherein the quality of deoxygenated desalted water is 3% of the fresh caprolactam quality, The quality of terephthalic acid is 5‰ of the quality of fresh caprolactam;

[0028] b. After fresh caprolactam, deoxygenated desalted water and terephthalic acid are mixed evenly in the compounding tank, the pump is pressurized to 8Bar, and the material is rapidly heated to 200°C by the preheater. After heating, the mixed material is sent to the pre-polymerization The pre-polymerization reaction (that is, the hydrolysis ring-opening and addition reaction of fresh caprolactam) is carried out in the reactor. The temperature of the pre-polymerization reaction is controlled at 275 ° ...

Embodiment 3

[0033] A kind of nylon 6 three-stage hydrolysis polymerization process comprises the following steps:

[0034] a, 4600 kilograms of reaction materials are added into the composite tank per hour and mixed uniformly. The reaction materials include fresh caprolactam, deoxygenated desalted water and terephthalic acid, wherein the quality of deoxygenated desalted water is 2% of the fresh caprolactam quality, The quality of terephthalic acid is 3‰ of the quality of fresh caprolactam;

[0035] b. After fresh caprolactam, deoxygenated desalted water and terephthalic acid are mixed evenly in the compounding tank, the pump is pressurized to 7.5 Bar, and the material is rapidly heated to 210°C by the preheater. After heating, the mixed material is sent to the pre-heater The pre-polymerization reaction (i.e. the hydrolysis ring-opening and addition reaction of fresh caprolactam) is carried out in the polymerization reactor. in 2.5 hours;

[0036] c. After the material has undergone high...

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PUM

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Abstract

The invention relates to a three-phase hydrolytic polymerization process for nylon 6. The process includes the steps of raw material preparing, pre-early polymerization reaction, early polymerization reaction, later polymerization reaction and cooling and slicing. The three-phase hydrolytic polymerization process for the nylon 6 has the advantages that a pre-early polymerization reaction kettle is added according to the hydrolytic polymerization reaction characteristics of fresh caprolactam, the highest pressure bearing ability of the pre-early polymerization reaction kettle is 15Bar, the early stage of the polymerization reaction of the fresh caprolactam is completed in the pre-early polymerization reaction kettle, and problems such as high product quality fluctuation caused by instable early polymerization liquid level can be solved; process controllability can be increased by adding the pre-early polymerization reaction kettle, product quality is increased, and the occurrence rate of polymerization accidents is reduced.

Description

technical field [0001] The invention relates to a process for producing nylon 6, in particular to a three-stage hydrolysis polymerization process for nylon 6. Background technique [0002] my country's nylon 6 industry began in the late 1950s and has a history of 50 years. In terms of polymerization process, it has experienced small capacity to large capacity; from intermittent production to continuous production, from trial production to industrialization, and the equipment structure has been continuously improved and perfected. , the process technology is becoming more and more reasonable and mature. [0003] At present, the preparation of high-quality nylon 6 adopts the hydrolytic polymerization process. The hydrolytic polymerization process of nylon 6 mainly includes three major reactions: chain initiation, chain growth, and chain balance. With the continuous expansion of nylon production capacity, the normal pressure continuous polymerization process has been unable to ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C08G69/16
CPCC08G69/16
Inventor 倪利锋梁万志雷建龙
Owner JIANGSU HONGSHENG NEW MATERIAL
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