Modified urea formaldehyde adhesive and preparation method thereof

A technology for modifying urea-formaldehyde and urea-formaldehyde adhesives, applied in the directions of adhesives, aldehyde/ketone condensation polymer adhesives, adhesive types, etc., can solve the problems of poor stability and short storage time of urea-formaldehyde adhesives, save work efficiency, The effect of improving initial viscosity and improving water solubility

Inactive Publication Date: 2013-09-04
HEILONGJIANG UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0003] The purpose of the present invention is to provide a modified urea-formaldehyde glue and its preparation method in order to solve the problems of poor stability and short storage time of the existing urea-formaldehyde glue

Method used

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Examples

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Effect test

specific Embodiment approach 1

[0015] Specific embodiment 1: A modified urea-formaldehyde glue of this embodiment is composed of 600-700 parts by weight of 37% formaldehyde, 300-400 parts of urea, and 35-45 parts by weight. It is made of melamine, 3 to 7 parts of phenol, 3 to 7 parts of sodium cellulose, 3 to 7 parts of ammonia water with a mass percentage content of 25% to 28%, and 3 to 7 parts of polyvinyl alcohol.

[0016] The ammonia water added to the urea-formaldehyde glue of this embodiment can further reduce the formaldehyde content, and the added phenol can further increase the hot water properties of the glue and reduce the free aldehyde content to a very low value. The free formaldehyde content in the urea-formaldehyde glue of this embodiment Less than 0.1%.

[0017] The sodium cellulose in the urea-formaldehyde glue of this embodiment can improve the initial viscosity of the glue, improve the water solubility of the glue, enable the urea-formaldehyde glue to react in an environment of 8°C to 10°C, an...

specific Embodiment approach 2

[0018] Specific embodiment two: this embodiment is different from specific embodiment one in that: the urea-formaldehyde glue is composed of 666 parts by weight of 37% formaldehyde, 333 parts of urea, 40 parts of melamine, 5 parts by weight It consists of 5 parts of phenol, 5 parts of sodium cellulose, 5 parts of 25%-28% ammonia water and 5 parts of polyvinyl alcohol. Others are the same as the first embodiment.

specific Embodiment approach 3

[0019] Specific implementation mode 3: The preparation method of a modified urea-formaldehyde glue of this embodiment is carried out according to the following steps: 1. Weigh 600-700 parts by weight of 37% formaldehyde, 35 parts by weight. ~45 parts of melamine, 3~7 parts of phenol, 3~7 parts of sodium cellulose, 3~7 parts of ammonia water with a mass percentage of 25%~28% and 3~7 parts of polyvinyl alcohol;

[0020] 2. Put the 37% formaldehyde weighed in step 1 into the reactor, and heat it up by the boiler. When the pressure of the boiler reaches 0.3 MPa and the temperature of formaldehyde in the reactor reaches 30℃~35℃, use Adjust the pH of the formaldehyde to 7.5-8.0 with a caustic soda solution with a concentration of 25%-30%, and then add the sodium cellulose weighed in step one;

[0021] 3. Continue heating until the temperature of the formaldehyde in the reactor reaches 36°C to 40°C, adjust the pH of the formaldehyde to 8.0 with a caustic soda solution with a concentration...

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Abstract

The invention discloses and relates to a modified urea formaldehyde adhesive and a preparation method of the modified urea formaldehyde adhesive. The modified urea formaldehyde adhesive disclosed by the invention solves the problems of poor stability and short storage time of the urea formaldehyde adhesive in prior arts. The urea formaldehyde adhesive disclosed by the invention comprises formaldehyde, urea, melamine, phenol, sodium cellulose, ammonia water, and polyvinyl alcohol. The preparation method comprises the following steps: (1) weighing each component, heating to 30-35 DEG C, regulating pH value, and adding sodium cellulose; (2) heating, adding the first part of urea, and regulating the pH value; (3) increasing the temperature to 92 DEG C, regulating the pH value, and holding temperature for reaction; and (4) regulating the pH value, observing the reaction end-point, regulating the pH value to finish the reaction, adding the second part of urea, mixing, decreasing the temperature to 70 DEG C, adding the third part of urea and the residual components, decreasing the temperature, regulating the pH value, and discharging to obtain the modified urea formaldehyde adhesive. The free formaldehyde content in the urea formaldehyde adhesive provided by the invention is less than 0.1%, and the storage time is two months. The modified urea formaldehyde adhesive provided by the invention is applied to the field of urea-formaldehyde adhesive.

Description

Technical field [0001] The invention relates to a modified urea-formaldehyde glue and a preparation method thereof. Background technique [0002] At present, the main raw materials of urea-formaldehyde glue used in wood processing industry are formaldehyde and urea. Among them, the content of formaldehyde is very high. Formaldehyde has the characteristics of strong volatility. The volatilized gas is very irritating to people and is harmful to human health. Therefore, the study of low-toxicity urea-formaldehyde glue has become an urgent problem to be solved. Recently, there have been related reports and studies. The use of a new type of modified urea-formaldehyde glue can make the free formaldehyde content less than 0.5%. However, the stability of the glue is low, the storage time is short, and there is no pre-compression during processing, which makes the plywood quality Low, thereby increasing labor intensity, is not conducive to the improvement of work efficiency, and the exi...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C09J161/30C09J11/06C09J11/08C08G12/38
Inventor 王阳鲁国明张宇张华张冬梅刘振久王勇战
Owner HEILONGJIANG UNIV
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