Method for preparing HMMM resin

Abstract

The invention discloses a preparation method for hexakis (methoxymethyl) melamine resin, namely, in the first step; 92% polyformaldehyde, melamine and methanol are reacted in alkaline environment through hydroxymethylation to generate the intermediate product hexamethylolmelamine crystals; in the second step, the intermediate product and methanol are reacted with organic acid through etherification to prepare the hexakis (methoxymethyl) melamine resin. The method of the invention is non-polluting, odorless and easy to operate. The hexakis (methoxymethyl) melamine resin produced through the method of the invention is stable and non-crystalline, which is used in coiled materials and baking varnish, with very good cross-linking effect.

Description

technical field [0001] The invention relates to a preparation method of a crosslinking agent, in particular to a preparation method of hexamethoxymethylmelamine resin. Background technique [0002] At present, the known hexamethoxymethylmelamine resin adopts melamine, 37% formaldehyde solution and methanol as main raw materials in the synthesis. The process is as follows: melamine and formaldehyde solution undergo methylolation reaction under alkaline conditions to obtain hexamethylolmelamine crystals; hexamethylolmelamine reacts with methanol under acidic conditions to generate hexamethoxymethyl Melamine. In this process, water is the medium of the first step reaction, which is introduced by 37% formaldehyde solution. In the second step reaction, methanol is the medium, and the existence of water will affect the degree of etherification, so it must be carried out before the second step reaction. The material is separated from water and excess formaldehyde. However, durin...

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Problems solved by technology

However, during the separation process, a large amount of formaldehyde gas will overflow, which will affect the environment and endanger the health of workers, making the operation impossible.