Optical grade polymethyl methacrylate continuous solution polymerization process and equipment used

Abstract

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. An optical-grade polymethyl methacrylate continuous solution polymerization equipment, which is composed of a refining distillation device, a polymerization reaction device, a two-stage devolatilization device and a wire drawing granulation device in series, including: feed refining tower, polymerization Reaction tank, recovery and refining tower, heater a, b, devolatilization tank a, b. An optical-grade polymethyl methacrylate continuous solution polymerization process, monomers, copolymers, stabilizers, molecular weight regulators, initiators, and solvents are subjected to ① refined distillation, ② polymerization reaction, ③ flash devolatilization and ④ The four-step operation of wire drawing and granulation is completed. The PMAA produced by the invention has the advantages of high safety, avoiding gel accumulation, improving product properties and color, low energy consumption, environmental protection and cleanness, good weather resistance, anhydrous polymerization, and no dark spots in the product.

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...

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

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