Optical-grade polymethylmethacrylate continuous solution polymerization process and equipment thereof

A technology of polymethyl methacrylate and polymerization process, which is applied in the field of preparation of polymer compounds, can solve the problems of poor devolatilization process, fast reaction rate, influence quality, etc., and achieves reduction of rapid reaction heat release, improvement of performance and quality. Color, the effect of reducing sewage treatment

Inactive Publication Date: 2009-01-07
SHANGHAI JINGQI POLYMER MATERIAL
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Bulk polymerization monomer concentration is high, it is easy to produce gel, and the reaction rate is fast, and the exothermic reaction is not easy to control in large-scale production
In the 1980s, the U.S. PTI company proposed that the solution polymerization method improved the aforementioned problems, and U.S. Patent No. 4,728,701 disclosed a method for acrylic ester polymerization on March 1, 1988; U.S. Patent No. 4,933,400 disclosed on June 12, 1990 A continuous solution polymerization method for methacrylate, but these polymerization methods use a solvent ratio as high as 60% of the feed, the reaction rate is too slow, and the volume of the reactor is significantly increased, resulting in high investment. At the same time, the process still has problems The following disadvantages: 1. The polymerization reaction temperature is lower than 100°C, and the dosage of the initiator and the molecular regulator is relatively increased, which affects the purity and recovery and refining problems
2. Two-stage polymerization tank is used, because the copolymerization speed ratio of MMA and its copolymers such as MA or EA is different, resulting in the difference in the copolymerization ratio of the first-stage reaction and the second-stage reaction of the polymer.
3. The devolatilization process is poor. When the solid content in the polymerization process reaches more than 40%, the polymerization solution is transported to the shell-and-tube heater for preheating through the gear pump. The process is from bottom to top. The polymerization solution passes through the heating tube of the heater, and At the end, the outlet pressure is controlled by a control valve to maintain the liquid state in the pipe. This method has a low heat transfer coefficient and poor heating effect, resulting in a bulky heater. The polymerization solution stays in it for a long time, and it is easy to produce oligomers and oligomers. Serious affect quality

Method used

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  • Optical-grade polymethylmethacrylate continuous solution polymerization process and equipment thereof
  • Optical-grade polymethylmethacrylate continuous solution polymerization process and equipment thereof
  • Optical-grade polymethylmethacrylate continuous solution polymerization process and equipment thereof

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0051] As shown in Figure 1, a kind of equipment used in the continuous solution polymerization process of optical grade polymethyl methacrylate is composed of a refining distillation device, a polymerization reaction device, a two-stage devolatilization device and a wire drawing granulation device combined in series, including: Main raw material storage tank 1, comonomer storage tank 2, solvent storage tank 3, recovery monomer storage tank 4, preheater 5, feed refining tower 6, reboiler 7, polymerization reaction tank 8, recovery refining tower 9 , Additive preparation tank 10, online agitator 11, filter device 12, die head 13, heater a14, heater b15, devolatilization tank a16, devolatilization tank b17, condenser a18~condenser e22, storage tank a23, b24 , pump a25 ~ pump j34, control valve a35 ~ control valve c37 and high viscosity gear pump a38 ~ high viscosity gear pump c40;

[0052] Among them, the main raw material storage tank 1, the comonomer storage tank 2, the solven...

Embodiment 2

[0070] Optical grade polymethyl methacrylate continuous type solution polymerization equipment used is the same as embodiment 1, when implementing optical grade polymethyl methacrylate continuous type solution polymerization technology, except the following conditions:

[0071] 1. During the refining distillation of the first step: the solvent accounts for 5% of the total weight of the reactants; the preheater 5 is heated to 60°C; 3 Pa;

[0072] 2. During the polymerization reaction in the second step: the temperature of the polymerization reaction is controlled at 130°C;

[0073] 3. During step ③ flashing devolatilization: heater a14 is heated to 220°C; the air pressure in devolatilization tank a16 is 4×10 3 Pa; the temperature at the top of recovery refining tower 9 is at 30°C, and the air pressure in the tower is at 4×10 3 Pa; the heater b15 is heated to 220°C;

[0074] Other conditions are all the same as in Example 1.

Embodiment 3

[0076] Optical grade polymethyl methacrylate continuous type solution polymerization equipment used is the same as embodiment 1, when implementing optical grade polymethyl methacrylate continuous type solution polymerization technology, except the following conditions:

[0077] 1. During the refining distillation of the ① step: the solvent accounts for 17% of the total weight of the reactant; the preheater 5 is heated to 95° C.; 4 Pa;

[0078] 2. During the polymerization reaction in the second step: the temperature of the polymerization reaction is controlled at 145°C;

[0079] 3. In step ③ flash devolatilization: Heater a14 is heated to 270°C; the air pressure in the devolatilization tank a16 is 2.5×10 4 Pa; the temperature at the top of recovery refining tower 9 is at 55°C, and the air pressure in the tower is at 2.5×10 4 Pa; the heater b15 is heated to 255°C;

[0080] Other conditions are all the same as in Example 1.

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Abstract

The invention relates to the preparation method of a polymer compound and a plant used therefor, in particular to a continuous solution polymerization process of optical-grade poly(methyl methacrylate) and the plant used therefor. The plant used for the continuous solution polymerization process of optical-grade poly(methyl methacrylate) comprises a refining and distillation device, a polymerization reaction device, a two-stage devolatilization device, and a wire-drawing and granulation device connected with each other in series, and specifically comprises a feed refining tower, a polymerization reaction groove, a recovering and refining tower, heaters a and b, and devolatilization tanks a and b. The continuous solution polymerization process can prepare optical-grade poly(methyl methacrylate) from monomers, a copolymer, a stabilizing agent, a molecular weight regulator, an initiator and a solvent according to the following four steps: (1) refining and distillation, (2) polymerization reaction, (3) flash devotilization and (4) wire drawing and granulation. The PMAA produced by the process has the advantages of high safety, no gel accumulation, improved physical properties and color of the produt, low energy consumption, environmental protection, clean production, good weathering resistance of the product, anhydrous polymerization, no black spots on the product, etc.

Description

technical field [0001] The invention relates to a preparation method of a polymer compound and equipment used, in particular to an optical-grade polymethyl methacrylate continuous solution polymerization process and equipment used. Background technique [0002] Polymethyl methacrylate, English name Polymethyl Methacrylate, referred to as PMMA, is a rigid and transparent thermoplastic material with a wide range of applications. Its polymerization preparation methods include suspension method, emulsification method, bulk method and solution method. Among them, the emulsification method The finished product has poor transparency and is expensive, so it is not suitable for commercial production. The preparation process of suspension method is: add initiator to MMA and copolymer, polymerize to a certain conversion rate, then add a large amount of water and suspending agent to further polymerize, PMMA forms beads suspended in water, dehydrated, washed, dried and then extruded mac...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C08F120/14C08F2/04C08J3/12
Inventor 杨青岚
Owner SHANGHAI JINGQI POLYMER MATERIAL
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