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Two-step method for preparing modified urea-formaldehyde glue for environment-friendly artificial board

An environmentally friendly wood-based panel and modified urea-formaldehyde technology, which is applied in adhesives, aldehyde/ketone condensation polymer adhesives, adhesive types, etc., can solve problems such as adhesive performance differences and complex reaction processes

Active Publication Date: 2014-10-08
GUANGXI UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Due to the extremely complicated reaction process of formaldehyde and urea, different groups and intermediate products are produced under different process conditions (temperature, pH value and F / U ratio), which eventually lead to huge differences in adhesive properties

Method used

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  • Two-step method for preparing modified urea-formaldehyde glue for environment-friendly artificial board
  • Two-step method for preparing modified urea-formaldehyde glue for environment-friendly artificial board
  • Two-step method for preparing modified urea-formaldehyde glue for environment-friendly artificial board

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0018] 1. Formula: 1500kg of industrial grade formaldehyde solution (mass concentration 37%), 1025kg of agricultural urea, 25kg of industrial grade melamine, appropriate amount of sodium hydroxide and formic acid, and 25% of the used sodium hydroxide aqueous solution mass concentration.

[0019] 2. Preparation process

[0020] Put all the formaldehyde aqueous solution into the reaction kettle, start the agitator to start heating, stop heating when the temperature rises to 40°C, and adjust the pH value to 5.0 with sodium hydroxide aqueous solution;

[0021] Add the first batch of urea 445kg and all the melamine, continue to heat up to 70°C, stop heating, add formic acid to adjust the pH value to 4.8; then raise the temperature naturally and maintain it at 90±3°C; Form in water, when the reactant drops into water with a water temperature of 42°C, it becomes white mist, which is the first end point;

[0022] Use sodium hydroxide aqueous solution to adjust the pH to 6.5, add th...

Embodiment 2

[0031] 1. Formula: 1200kg of industrial grade formaldehyde solution (mass concentration 37%), 840kg of agricultural urea, 10kg of industrial grade melamine, appropriate amount of sodium hydroxide and formic acid, and 30% of the used sodium hydroxide aqueous solution mass concentration.

[0032] 2. Preparation process

[0033] Put all the formaldehyde aqueous solution into the reaction kettle, start the agitator to start heating, stop heating when the temperature rises to 40°C, and adjust the pH value to 5.2 with sodium hydroxide aqueous solution;

[0034] Add the first batch of urea 360kg and all the melamine, continue to heat up to 70°C, stop heating, add formic acid to adjust the pH value to 4.6; then raise the temperature naturally and maintain it at 90±2°C; Form in water, when the reactant drops into water at a temperature of 40°C, it becomes white mist, which is the first end point;

[0035] Use sodium hydroxide aqueous solution to adjust the pH to 6.3, add the second...

Embodiment 3

[0044] 1. Formula: 1150kg of industrial grade formaldehyde solution (mass concentration 37%), 850kg of agricultural urea, 32kg of industrial grade melamine, appropriate amount of sodium hydroxide and formic acid, and 28% of the used sodium hydroxide aqueous solution mass concentration.

[0045] 2. Preparation process

[0046] Put all the formaldehyde aqueous solution into the reaction kettle, start the agitator to start heating, stop heating when the temperature rises to 40°C, and adjust the pH value to 4.8 with sodium hydroxide aqueous solution;

[0047] Add the first batch of urea 360kg and all the melamine, continue to heat up to 70°C, stop heating, add formic acid to adjust the pH value to 4.5; then raise the temperature naturally and maintain it at 90±3°C; Form in water, when the reactant drops into water at a temperature of 45°C, it becomes white mist, which is the first end point;

[0048] Use sodium hydroxide aqueous solution to adjust the pH to 6.2, add the second ba...

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Abstract

The invention discloses a two-step method for preparing modified urea-formaldehyde glue for an environment-friendly artificial board. The modified urea-formaldehyde glue mainly comprises the following raw materials in parts by weight: 56-60 parts of formaldehyde aqueous solution with the mass concentration of 37%, 42-39 parts of agricultural urea, 0.2-2 parts of industrial-grade melamine, and is prepared by a weak acid step and a weak base step, wherein for the weak acid step, addition and condensation polymerization reactions of urea and formaldehyde are simultaneously conducted in a weak acid medium with pH value of 4-6.5. An inventor does improvement on the basis of the three-step weak base technology of the traditional modified urea-formaldehyde glue, the improvement mainly lies in all steps are integrated into weak acid-weak base two steps, the feeding mode that formaldehyde and melamine are fed at a time is adopted, and urea is fed in three to four batches. By applying the two-step method, the molecular structure of the glue can be improved, about a half of acid-base consumption can be reduced, the strength of the glue can also be improved, the release amount of formaldehyde can be reduced, and the modified urea-formaldehyde glue has the characteristics of low cost, high performances, environment friendliness and the like.

Description

technical field [0001] The invention belongs to the technical field of urea-formaldehyde glue for wood-based panels (fiberboard and particle board), and in particular relates to a two-step method for preparing modified urea-formaldehyde glue for environment-friendly wood-based panels. Background technique [0002] In 2012, the total output of wood-based panels in my country reached 223 million m 3 , 7.6 times that of 2002. Due to changes in domestic and foreign situations, the wood-based panel industry has gradually entered a period of adjustment and transformation from a stage of rapid development in recent years. Many companies only rely on the national tax rebate policy to achieve meager profits. [0003] Wood-based panels are a resource-dependent industry, and the two major items of wood and chemical raw materials account for about 70% of the cost. Therefore, the production of lightweight, high-performance wood-based panels has become an important part of transformatio...

Claims

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Application Information

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IPC IPC(8): C08G12/38C09J161/30
Inventor 张运明刘幽燕唐爱星
Owner GUANGXI UNIV
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