Method for preparing high-solid latex

Abstract

The invention relates to the field of latex preparation, in particular to a method for preparing high-solid latex. The method for preparing the high-solid latex is characterized by comprising the following steps of (1) fast synthesizing small-grain-diameter rubber latex conforming to the foaming rubber requirements; (3) performing grain-diameter expansion on the small-grain-diameter rubber latex to reach 500 to 1000nm by carboxylic acid containing macromolecule hydrates; (3) separating rubber ingredients from water phases by a centrifugal machine so as to improve the solid content of the rubber latex to be 80 percent or higher.

Description

technical field [0001] The invention relates to the field of latex preparation, in particular to a method for preparing high-solid latex. Background technique [0002] Usually, the emulsion polymerization is used to adjust the water ratio, adjust the amount of emulsifier and electrolyte to enlarge the particle size, reduce the viscosity of the latex, and increase the solid content of the latex. However, the particle size of the latex obtained by this method is difficult to exceed 200nm, and the solid content is difficult to exceed 45%. Therefore common emulsion polymerization method is difficult to make the required solid content of foamed latex, the method for preparing high-solid latex at home and abroad has following several kinds at present: [0003] 1. The method of adding monomer initiator after agglomeration and increasing the reaction temperature during the reaction process. After agglomeration, the reaction speed will decrease. Although the reaction temperature can ...

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Problems solved by technology

[0003] 1. The method of adding monomer initiator after agglomeration and increasing the reaction temperature during the reaction process. After agglomeration, the reaction speed will decrease. Although the reaction temperature can be increased by adding monomer and initiator in the later stage And other measures to improve the reaction speed, but the effect is not obvious, so the reaction time is very long, reaching more than 36 hours, the latex coagulation is as high as more than 80%, the latex viscosity is very high, the latex solid content is not high, usually in the range of 56%-59% Among them, the particle size of the latex is not large, about 300nm, so it is difficult to make the latex required by the foamed rubber by this method;

[0004] 2. Add electrolytes to expand the particle size, then heat to evaporate water to increase the solid content of the latex. The electrolytes added in this method include NaCl Na 2 SO 4 K 2 CO 3 Inorganic acid, organic acid, etc., but there are two difficulties in increasing the particle size of the liposome by increasing the electrolyte. A. The range of diameter expansion is limited. Adding acetic acid to expand the particle size of the liposome is difficult to expand the particle size to more than 450mm. B. It is very risky to use electrolyte to expand the diameter, and it is easy to cause partial or even complete demulsification during the diameter expansion. Even if the diameter expansion is successful, this latex cannot be stored and transported; Evaporation and dehydration increases the concentration to increase the solid content; however, this method is almost impossible to achieve in industry, because evaporative dehydration increases the electrolyte concentration in the body, and if the electrolyte concentration is too high, the limb milk will inevitably break and cannot be really high. solid latex;

[0005] 3, do agglomerating agent with the latex containing carboxylic acid, enlarge the particle diameter of limb milk, centrifuge dehydration then, improve solid content, at present, this method is the most advanced method for preparing high-solid latex, but there are following deficiencies in this method: A , to point out the particle size of the attached latex; B, the solid content of the high-solid latex produced by this method in China is less than 65%, C, slag is produced in the diameter expansion process, and the quality cannot be guaranteed; D, the small particle size latex contains the formation time Longer; E, the diameter expansion time is not indicated; F, the obtained latex has a higher viscosity; G, adding some small particle latex to reduce the viscosity of high-solid latex