Special urea-formaldehyde resin adhesive for producing environment-friendly medium-high density boards as well as preparation process and use method of special urea-formaldehyde resin adhesive

Abstract

The invention relates to a special urea-formaldehyde resin adhesive for producing environment-friendly medium-high density fiberboards as well as a preparation process and a use method of the specialurea-formaldehyde resin adhesive, and belongs to the technical field of production of continuous flat-pressing environment-friendly medium-high density fiberboards. According to the technical scheme,formaldehyde, urea, melamine and industrial salt are used as raw materials, and urea is added in four batches; in addition, two auxiliary chemical raw materials including formic acid and caustic sodaare added; and according to the set molar ratio of the adhesive, milk white liquid is formed through a weak base-weak acid-weak base process, and the milk white liquid is the urea-formaldehyde resin adhesive. The production operation process of three times of condensation polymerization and four batches of urea addition is adopted, production control is facilitated, and the quality of the adhesiveis more stable. The main raw materials of the adhesive are formaldehyde and urea, a small amount of melamine is added for modification, industrial salt filling is added, the auxiliary raw materials are formic acid and caustic soda, operation is convenient, the cost is reduced, the manufacturing method is simple, the varieties of chemical raw materials are few, and meanwhile the physicochemical and mechanical indexes and the application effect of the using performance of the product are guaranteed.

Description

technical field [0001] The invention relates to a special urea-formaldehyde resin adhesive for producing environment-friendly medium and high-density boards, a preparation process and a use method thereof, and belongs to the production technical field of continuous flat pressing environment-friendly medium and high-density fiberboards. Background technique [0002] At present, in the production of continuous flat-pressed medium and high-density fiberboard, most of the urea-formaldehyde resin adhesives used are relatively complicated production processes, and there are many types of main and auxiliary chemical raw materials added, which brings a lot of inconvenience to production operations and high costs. Due to the traditional medium and high density fiberboard production process, the temperature requirement in the polycondensation reaction stage is too high, generally 96-98 degrees, and only one polycondensation reaction or two polycondensation reactions are performed, whic...

AI Technical Summary

Problems solved by technology

[0002] At present, in the production of continuous flat-pressed medium and high-density fiberboard, most of the urea-formaldehyde resin adhesives used adopt relatively complicated production processes, and there are many types of main and auxiliary chemical raw materials added, which brings a lot of inconvenience to the production operation and high cost.

Due to the traditional medium and high density fiberboard production process, the temperature requirement in the polycondensation reaction stage is too high, generally 96-98 degrees, and only one polycondensation reaction or two polycondensation reactions are performed, which is not conducive to safe production

Or carry out three polycondensation reactions, but the end point of the second polycondensation reaction and the third polycondensation reaction end point are difficult to accurately detect, there is a greater risk, the production cycle is long, and the bonding strength is low, such as the existing technology 201710952584.6

In addition, if the temperature of the polycondensation reaction is too high, if the salt content in urea is too high, as the polycondensation reaction accelerates and the temperature rises, a large amount of foam will be generated, which is not conducive to the production and operation of medium and high density fiberboard.