Method for producing alpha-cyanoacrylate adhesive by continuous feeding

Abstract

The invention relates to a method for producing an alpha-cyanoacrylate adhesive by continuous feeding, which comprises the following steps: pumping ethyl cyanoacetate and an organic solvent into a first mixer by a feeding pump respectively, conducting uniform mixing, and preheating the mixed material 1 by a heat exchanger to obtain a preheated material 1; and converging and mixing the preheated material 1 with formaldehyde and a basic catalyst entering through a feeding pump in a second mixer to obtain a mixed material 2, performing primary polycondensation reaction on the mixed material 2, and then performing polycondensation reaction to obtain an ethyl alpha-cyanoacrylate prepolymer with centralized molecular weight distribution. The method provided by the invention maintains a constantmolar ratio of ethyl cyanoacetate to formaldehyde in the reaction process. According to the invention, continuous feeding of raw materials in the synthesis stage of the ethyl alpha-cyanoacrylate prepolymer is realized, the homogeneity of the polymerization degree of the ethyl alpha-cyanoacrylate prepolymer is improved, the depolymerization temperature range of the ethyl alpha-cyanoacrylate prepolymer is reduced, the energy consumption in the production process is reduced, and the yield and the production efficiency of the product are improved.

Description

technical field [0001] The invention belongs to the field of preparing α-cyanoacrylate ethyl adhesive, and more specifically relates to a method for continuously feeding the α-cyanoacrylate adhesive. Background technique [0002] α-Ethyl cyanoacrylate, also known as 502 glue, is one of the most common types of adhesives on the market. Due to its single component, low viscosity, fast curing speed, high bonding strength, good transparency, Basic non-toxic, easy to use and other advantages, has been widely used in the bonding of metal, plastic, wood, rubber, leather, ceramics, glass and many other materials. [0003] The traditional production process of α-ethyl cyanoacrylate adhesive is: first add ethyl cyanoacetate and organic solvent to the reaction kettle, and then gradually add formaldehyde aqueous solution containing alkaline catalyst, or, first add Aqueous formaldehyde solution, organic solvent, basic catalyst, and then gradually add ethyl cyanoacetate dropwise to fully...

AI Technical Summary

Problems solved by technology

[0004] According to the above description, the traditional preparation process of ethyl α-cyanoacrylate adopts the feeding method of adding dropwise formaldehyde aqueous solution or ethyl cyanoacetate, and the molar ratio of ethyl cyanoacetate and formaldehyde will constantly change during the polycondensation process, resulting in The molecular weight distribution range of the generated α-ethyl cyanoacrylate prepolymer is very wide, resulting in a wide range of depolymerization temperature, and the later depolymerization temperature exceeds 200 ° C, which is very unfavorable to product quality

At the same time, the traditional process adds the organic solvent at one time, which will play a dilution role, reduce the initial concentration of the reactants, and slow down the speed of the polycondensation reaction

This will not only increase the energy consumption in the depolymerization process, but also reduce the yield and production efficiency of the product

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