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Method for preparing urea-formaldehyde resin adhesive

A urea-formaldehyde resin and adhesive technology, applied in the direction of adhesives, aldehyde/ketone condensation polymer adhesives, adhesive types, etc., can solve the problems of high production cost, low environmental protection coefficient, large amount of glue, etc., and achieve production costs. Low, small amount of glue, the effect of reducing production costs

Active Publication Date: 2015-04-22
普洱市卫国林业局
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0004] In order to solve the problems of the existing urea-formaldehyde resin adhesive with large amount of glue, low environmental protection coefficient, high production cost and low efficiency during the production of medium density fiberboard, the invention provides a preparation method of urea-formaldehyde resin adhesive

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0013] (1) Heat 100 parts by mass of formaldehyde to 38°C, adjust the pH value to 7.8 with a NaOH solution with a mass concentration of 30%, then add 0.0030 parts by mass of tapioca starch and 33.98 parts by mass of urea, and heat up to 70°C to stop heating After that, wait for it to naturally heat up to 90°C for 30 minutes;

[0014] (2) Use a CHOOH solution with a mass concentration of 42% to adjust the pH value of the mixture obtained in step (1) to 4.5, and then react to the cloud point at 92°C; then adjust the pH value to 6.3 with a NaOH solution with a mass concentration of 28% , finally add the cassava starch of 0.0030 mass parts, stir and make the cassava starch dissolve completely; The cassava starch used is provided by Guangxi Yunlong Science and Technology Co., Ltd. manufacturer;

[0015] (3) Add 18.46 parts by mass of urea to the mixture obtained in step (2), and react at 92°C until the mixture is dropped into 69°C water to form a white mist, and the reaction is ter...

Embodiment 2

[0017] (1) Heat 100 parts by mass of formaldehyde to 40°C, adjust the pH value to 7.8 with NaOH solution with a mass concentration of 30%, then add 0.0029 parts by mass of additive A and 33.85 parts by mass of urea, and heat up to 70°C to stop After heating, wait for the temperature to rise naturally to 89°C for 28 minutes;

[0018] (2) Use a CHOOH solution with a mass concentration of 40% to adjust the pH value of the mixture obtained in step (1) to 4.4, and then react to the cloud point at 90°C; then adjust the pH value to 6.2 with a NaOH solution with a mass concentration of 29% , finally add 0.0035 parts by mass of auxiliary agent A, and stir to completely dissolve auxiliary agent A;

[0019] (3) Add 18.46 parts by mass of urea to the mixture obtained in step (2), and react at 88°C until the mixture is dropped into 68°C water to form a white mist, and the reaction is terminated, and then adjusted with a NaOH solution with a mass concentration of 29%. When the pH value rea...

Embodiment 3

[0021] (1) Heat 100 parts by mass of formaldehyde to 42°C, adjust the pH value to 7.8 with a 30% NaOH solution, then add 0.0027 parts by mass of tapioca starch and 34.23 parts by mass of urea, and heat up to 70°C to stop heating After that, wait for its natural temperature to rise to 88°C for 32 minutes;

[0022] (2) Adjust the pH value of the mixture obtained in step (1) to 4.6 with a CHOOH solution with a mass concentration of 39%, and then react to the cloud point at 88°C; then adjust the pH value to 6.3 with a NaOH solution with a mass concentration of 31% , finally add the tapioca starch of 0.0038 mass parts, stir and make tapioca starch dissolve completely;

[0023] (3) Add 18.46 parts by mass of urea to the mixture obtained in step (2), and react at 85°C until the mixture is dropped into 70°C water to form a white mist, and the reaction is terminated, and then adjusted with a NaOH solution with a mass concentration of 28%. When the pH value reaches 7.8, when the temper...

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PUM

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Abstract

The invention provides a method for preparing urea-formaldehyde resin adhesive. The method includes heating up formaldehyde, adjusting the potential of hydrogen (pH) value by a NaOH solution, adding an auxiliary A and urea, after heating up, reacting for couple of minutes after temperature rises naturally to a certain temperature, adjusting the pH value by a CHOOH solution, then reacting at a certain temperature to cloud point, adjusting the pH value by the NaOH solution, finally adding the auxiliary A and the urea, ceasing the reacting when a white mist shape is presented in water, adjusting the pH value by the NaOH solution, adding the urea after cooling to a certain temperature, then reacting for couple of minutes at a certain temperature, adding the urea, stirring and cooling, and finally adjusting the pH value by the NaOH solution to obtain the urea-formaldehyde resin adhesive. According to the method, the auxiliary is utilized, so that the property of the urea-formaldehyde resin adhesive can be improved, the content of free formaldehyde can be reduced, the formaldehyde, the urea and dibasic auxiliary are utilized for synthesizing the urea-formaldehyde resin adhesive, the quality index of the urea-formaldehyde resin adhesive meets requirements of medium density fiberboard production, and the content of the free formaldehyde is smaller than or equal to 0.15%.

Description

technical field [0001] The invention relates to a preparation method of a urea-formaldehyde resin adhesive, which belongs to the technical field of adhesives. Background technique [0002] The synthesis of urea-formaldehyde resin has a history of more than 160 years. With the development of wood-based panels, urea-formaldehyde resin has been greatly developed. Due to formaldehyde pollution. The wood industry mainly uses low molar ratio urea-formaldehyde resins. In recent years, in the synthesis process of low molar ratio urea-formaldehyde resin, adding different modifiers can reduce the content of free formaldehyde in the resin and improve the comprehensive indicators of the resin such as bonding strength, aging resistance, and storage stability. In a word, the research and application of low molar ratio urea-formaldehyde resin has made great progress, but the synthesis process of low molar ratio urea-formaldehyde resin is not perfect, and the curing characteristics and cu...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C08G12/36C09J161/24C09J11/08
Inventor 罗亚春
Owner 普洱市卫国林业局