A kind of method for preparing eva elastomer

Abstract

The invention discloses a method for preparing EVA elastomer. The method included the step of controlling the pressure of ethylene to make the ethylene completely liquefied in a single reactor with alcohols as a solvent, so that the ethylene and the vinyl acetate are subjected to liquid-liquid single-phase copolymerization and the EVA elastomer is obtained. According to the method based on the existing EVA-elastomer-solution polymerization process, the pressure of ethylene is controlled to make the ethylene completely liquefied so that the liquid-liquid copolymerization can improve the comonomer contact efficiency as well as the solubility of ethylene in the liquid phase, complete the solution single-phase copolymerization, and greatly improve the monomer copolymerization rate and the diffusion as well as the initiator efficiency of the free radicals in the copolymer solution. According to the application requirements of different polymerization products, by adjusting the solvent, the method greatly improves the copolymerization rate and the high solid content of a high-viscosity system. Using the single-reactor process, the method is also capable of avoiding the high-cost and complex-manipulation problem resulting from a raw-material process device of the multi-reactor process. Therefore, the method has high industrial application value.

Description

technical field [0001] The invention relates to a method for preparing a polymer material, in particular to a method for preparing an EVA elastomer. Background technique [0002] Ethylene-vinyl acetate copolymer (EVA) is a highly branched random copolymer, which is composed of non-polar ethylene monomer (E) and highly polar vinyl acetate monomer (VAc). One of the main ethylene derived copolymers. Compared with polyethylene (PE), due to the introduction of VAc monomer into the molecular segment, the crystallinity of the polymer is greatly reduced, and its aging resistance, impact resistance, compatibility and flexibility are significantly enhanced. The performance of EVA is closely related to the VAc content of the copolymerization system. The performance of EVA products with low VAc content is similar to that of LDPE; the performance of EVA products with high VAc content is infinitely close to that of rubber elastomers. During the polymerization process, by controlling the...

AI Technical Summary

Problems solved by technology

[0003] In the prior art, there are many problems such as complex solvent system, high ethylene pressure difficult to control, gas-liquid two-phase copolymerization reaction system, complicated process and equipment, high cost and energy consumption, etc.

Images