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Method for continuously preparing optical-grade polymethyl methacrylate

A technology of polymethyl methacrylate and acrylates, which is applied in the field of continuous preparation of optical-grade polymethyl methacrylate, can solve the problems of high proportion of solvent, damage to polymer thermal degradation resistance, and large energy consumption. Achieve high polymerization conversion effect

Inactive Publication Date: 2014-01-29
PETROCHINA CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

This process has the following disadvantages: the proportion of solvent used in the polymerization method is as high as 60% of the feed amount, and the reaction rate is too slow
However, due to the use of a large amount of solvent, it takes a lot of energy to remove these volatiles in the post-treatment process.
In addition, the residual solvent in the polymer will damage the thermal degradation resistance of the polymer and reduce the purity of the polymer

Method used

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  • Method for continuously preparing optical-grade polymethyl methacrylate

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0023] Add initiator tert-butyl peroxide and chain transfer agent tert-dodecyl mercaptan to the mixture of methyl methacrylate and methyl acrylate, and mix the above raw materials in proportion. Mixture feed composition: based on 100 parts (mass) of monomer mixture, 97 parts of methyl methacrylate, 3 parts of methyl acrylate, 0.005 parts of tert-butyl peroxide and 0.2 parts of tert-dodecyl mercaptan . Charge nitrogen into the monomer mixture, remove the mixed oxygen, and control the oxygen content therein at 2 ppm. The mixed solution of the above raw materials was continuously added to the circulating tubular reactor replaced by nitrogen with a pump. The material circulates in the reactor through the circulation pump, and the ratio of the material circulation rate to the feed rate is controlled at 80:1. The temperature in the circulating tubular reactor was maintained at 150°C. Until the polymerization conversion rate reaches 59.5%, the polymerization mixture is transported...

Embodiment 2

[0025] The same method as in Example 1 was used. In addition to the composition of the mixed solution: 95 parts of methyl methacrylate, 5 parts of methyl acrylate, the ratio of the material circulation rate to the feed rate is 90:1, and the absolute pressure of the four exhaust ports is sequentially controlled to 120KPa, 50KPa, 15KPa and 4KPa, other conditions are identical with embodiment 1. After the reaction is complete, the polymer mixture is sent to a vented extruder for devolatilization. The polymer test results are listed in Table 1.

Embodiment 3

[0027] The same method as in Example 1 was used. In addition to the composition of the mixed solution: 97 parts of methyl methacrylate, 3 parts of ethyl acrylate, the temperature of the circulating tubular reactor is 145 °C, the ratio of material circulation rate to feed rate is 50:1, and four exhaust ports The absolute pressure is controlled to be 130KPa, 60KPa, 10KPa and 5KPa successively, and other conditions are identical with embodiment 1. After the reaction is complete, the polymer mixture is sent to a vented extruder for devolatilization. The polymer test results are listed in Table 1.

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Abstract

The invention relates to a method for continuously preparing optical-grade polymethyl methacrylate. The method comprises the following steps of: continuously supplying (meth)acrylate monomer or the solution containing not more than 5% of inert solvent into a circulating tube type reactor for polymerization, wherein the polymerization temperature is controlled within the range of 130-160 DEG C and the polymer content is controlled within the range of 40-65%; continuously sending the reaction material into a heater for further polymerization, wherein the polymerization temperature is set within the range of 140-170 DEG C, and the content of the polymer is increased to 55-80%; sending the obtained reaction mixture into a devolatilization extruder to continuously remove a volatile substance by separation, wherein the ratio of material circulation rate to feeding rate inside the circulating tube type reactor is controlled within the range of 40:1-120:1. A highly-pervious pure polymethyl methacrylate molding compound product can be stably prepared by adopting the method provided by the invention.

Description

technical field [0001] The present invention relates to a process for preparing polymers by bulk polymerization or solution polymerization. It is especially suitable for the continuous preparation of optical grade polymethyl methacrylate molding compound. Background technique [0002] (Meth) acrylate polymer (mostly called PMMA) is widely used as a transparent material with excellent performance in various lighting equipment, optical components, various instrument dials, covers, dials, commercial advertising windows, billboards , aircraft cockpit glass, bulletproof glass for aircraft and automobiles, various medical and military glass and other fields. In recent years, in addition to being widely used in the above fields instead of glass, various special PMMAs have been used more and more in the fields of medicine, building profiles, communications, electronic appliances, etc., and have become a hot spot for investment. [0003] In the polymerization process, although the ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C08F220/14C08F2/02C08F2/04C08F2/06C08F2/01
Inventor 刘哲赵金德王硕胡慧林李晶陈继新田月陈晓鸣
Owner PETROCHINA CO LTD
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