Method for preparing urea-formaldehyde resin adhesive

A technology for urea-formaldehyde resins and adhesives, which is applied in adhesives, aldehyde/ketone condensation polymer adhesives, adhesive types, etc. It can solve the problem that the limit of free formaldehyde release is not enough to protect human health, and the limit of free formaldehyde release is very low and other problems, to achieve the effect of reducing volume shrinkage, reducing production costs, increasing adhesive strength and water resistance

Inactive Publication Date: 2008-06-04
LANZHOU UNIVERSITY
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The new standard has a very low limit on the release of free formaldehyde, but the wood-based panels currently produced in my country are still difficult to meet the requirements of the new national standard. This is mainly due to the use of urea-formaldehyde resin adhesives with high free formal

Method used

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  • Method for preparing urea-formaldehyde resin adhesive

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Effect test

Embodiment 1

[0023] 1. Add 190g of 36% formaldehyde in a 500ml container, add 1g of 30% sodium hydroxide solution under stirring, then heat to 40℃, add 56g of urea, the molar ratio of urea to formaldehyde is 1:2.45, and then The temperature was raised to 80℃ and the reaction was stirred for 60 minutes. When the pH value of the solution was 6.5, 19g of urea was added. The molar ratio of urea to formaldehyde was 1:1.84. The temperature of the solution was kept at 80℃ for 30 minutes. After 30 minutes, 20 was added. % Ammonium chloride solution 1g, continue to keep the temperature of the solution at 80℃ for 60 minutes, when the pH of the solution is 5, add 1g of 30% sodium hydroxide solution, keep the temperature of the solution at 80℃ React for 30 minutes to make the pH of the solution 7 to prepare raw gum;

[0024] 2. Add 17g of urea to the raw gum prepared in step one under stirring. The molar ratio of urea to formaldehyde is 1:1.5-1.40. The solution is heated to 90°C and kept at this temperatu...

Embodiment 2

[0027] 1. Add 190g of 36% formaldehyde in a 500ml container, add 1g of 30% sodium hydroxide solution under stirring, then heat to 60℃, add 56g of urea, the molar ratio of urea to formaldehyde is 1:2.45, and then The temperature is raised to 90℃ and the reaction is stirred for 60 minutes. When the pH of the solution is 7.5, add 19g of urea. The molar ratio of urea to formaldehyde is 1:1.84. Keep the temperature of the solution at 85°C for 30 minutes. After 30 minutes of reaction, add 20 % Ammonium chloride solution 1g, keep the temperature of the solution at 85℃ for 60 minutes, when the pH of the solution is 6, add 1g of 30% sodium hydroxide solution, keep the temperature of the solution at 85℃ React for 30 minutes to make the pH of the solution 7 to prepare raw gum;

[0028] 2. Add 23g of urea to the raw rubber prepared in step one under stirring. The molar ratio of urea to formaldehyde is 1:1.5-1.40. The solution is heated to 96°C and kept at this temperature for 30 minutes. Afte...

Embodiment 3

[0031] 1. Add 190g of 36% formaldehyde in a 500ml container, add 1g of 30% sodium hydroxide solution under stirring, then heat to 40℃, add 56g of urea, the molar ratio of urea to formaldehyde is 1:2.45, and then The temperature was raised to 80℃ and the reaction was stirred for 60 minutes. When the pH value of the solution was 6.5, 19g of urea was added. The molar ratio of urea to formaldehyde was 1:1.84. The temperature of the solution was kept at 80℃ for 30 minutes. After 30 minutes, 20 was added. % Ammonium chloride solution 1g, continue to keep the temperature of the solution at 80℃ for 60 minutes, when the pH of the solution is 5, add 1g of 30% sodium hydroxide solution, keep the temperature of the solution at 80℃ React for 30 minutes to make the pH of the solution 7 to prepare raw gum;

[0032] 2. Add 23g of urea to the crude rubber prepared in step one under stirring. The molar ratio of urea to formaldehyde is 1:1.5-1.40. The solution is heated to 90°C and kept at this temp...

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Abstract

The invention discloses a preparation method for urea-formaldehyde resin adhesive, which is an adhesive produced by adopting ethylene urea, melamine or polyvinyl alcohol as formaldehyde catching agent and added with urea, potato starch residue and urea-formaldehyde resin to react. The invention has low formaldehyde content, can meet the requirement of low cost for composite sheet adhesive and has all excellent performances of urea-formaldehyde resin adhesive and the production cost is reduced; therefore, a practical adhesive that can be afforded entirely by each composite plate processing enterprises is obtained.

Description

Technical field [0001] The invention relates to a preparation method of an environment-friendly urea-formaldehyde resin adhesive, in particular to a method for preparing a urea-formaldehyde resin adhesive using a composite formaldehyde trapping agent. Background technique [0002] my country is a Shaolin country, and there is a big contradiction between wood supply and demand. An important way to solve this contradiction is to vigorously develop the production and utilization of composite panels centered on wood-based panels. Using urea-formaldehyde resin adhesive to produce 1 cubic meter of particleboard can replace 3.1 cubic meters of logs; while using urea-formaldehyde resin adhesive to produce 1 ton of fiberboard can replace 5.6 cubic meters of log. That is to say, adhesives are of great significance to improving the utilization rate of wood; at the same time, the consumption of adhesives in the wood industry is also huge, in composite panels such as wood-based panels, plywoo...

Claims

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Application Information

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IPC IPC(8): C09J161/24C09J11/08C09J11/06
Inventor 武小莉石辉文刘涛
Owner LANZHOU UNIVERSITY
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