Method for producing binary chloride-vinyl acetate resin by homogeneous solution polymerization method

Abstract

The invention relates to a method for producing binary vinyl chloride-vinyl acetate resin by a homogeneous solution polymerization method, which comprises the following steps: 1) carrying out vacuum pumping operation on a polymerization kettle until the pressure is lower than0.01MPa;2) adding vinyl chloride (1), vinyl acetate (2) and ketones (such as methyl ethyl ketone, acetone and the like)(3) into a polymerization kettle according to a certain proportion, wherein the feeding amount is 70-100 percent of the effective volume of the polymerization kettle, and closing a feeding valve of the polymerization kettle; 3) heating the polymerization kettle, and adding a certain amount of initiator (peroxide or azo compound) when the temperature reaches 48 DEG C or 62 DEG C; (4) controlling the reaction temperature to be 48 + / - 3 DEG C or 62 + / - 3 DEG C; and 4) detecting the specific gravity in the polymerization kettle by using an on-line density detector, determining that the reaction reachesthe end point when the specific gravity is 0.87-1.0, and cooling the polymerization kettle to normal temperature. The technology fills up the domestic blank, firstly adopts a solution method to produce the polynary chloride-vinyl acetate resin, and is superior to similar products produced by a suspension method in the aspects of solubility, transparency, compatibility with other materials, molecular weight distribution uniformity, impurity content and the like.

Description

technical field [0001] The invention belongs to the field of macromolecules, and in particular relates to a preparation method of a binary vinyl acetate resin. Background technique [0002] Vinyl chloride resin, also known as vinyl acetate copolymer resin, was first developed and produced by Germany and the United States in 1929, and its use was introduced in 1933. Up to now, various methods such as bulk polymerization, emulsion polymerization, suspension polymerization and solution polymerization have been invented, among which suspension polymerization and emulsion polymerization are the most widely used. [0003] Now the main production enterprises in the world include Dow Chemical Co., Ltd. of the United States, Nissin Chemical Industry Co., Ltd. of Japan, Wacker Chemical Co., Ltd. of Germany, and Hanwha Petrochemical Co., Ltd. of South Korea. Among them, the VMCC and VMCA brand products produced by Dow Chemical in the United States using the solution method have passed...

AI Technical Summary

Problems solved by technology

[0006] The disadvantage of bulk polymerization is that the system has high viscosity, the polymerization heat is not easy to discharge, the phenomenon of automatic acceleration is serious, and explosion polymerization is easy to occur. The light one affects the product quality, and the severe one makes the polymerization fail.

The disadvantages of emulsion polymerization are: when a solid polymer is needed, the emulsion needs to undergo coagulation, filtration, washing, drying and other processes, and the production cost is higher than that of suspension polymerization; the emulsifier in the product is difficult to remove, which affects the performance of the polymer

[0008] Due to the late start, the suspension polymerization method is mostly used to produce binary products. The product types and uses are relatively single, and it is difficult to meet domestic demand.

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