Modified urea-formaldehyde glue 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 increasing hot water properties

Inactive Publication Date: 2012-07-25
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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specific Embodiment approach 1

[0015] Specific embodiment one: a kind of modified urea-formaldehyde glue of the present embodiment, by weight ratio is by the formaldehyde that the mass percent content of 600~700 parts is 37%, 300~400 parts of urea, 35~45 parts of formaldehyde It is made of melamine, 3-7 parts of p-chlorophenol, 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.

[0016] The ammonia water added in the urea-formaldehyde glue of this embodiment can further reduce the formaldehyde content, and the p-chlorophenol added can make the glue further increase the hot water property of the glue, so that the free aldehyde content is reduced to a very low value. Free formaldehyde in the urea-formaldehyde glue of this embodiment The formaldehyde content is less than 0.1%.

[0017] The cellulose sodium in the urea-formaldehyde glue of this embodiment can improve the initial viscosity of the glue, improve the water solubility of th...

specific Embodiment approach 2

[0018] Specific embodiment two: the difference between this embodiment and specific embodiment one is: urea-formaldehyde glue is made of 37% formaldehyde, 333 parts of urea, 40 parts of melamine, 5 parts by weight of urea-formaldehyde glue in parts by weight 4 p-chlorophenol, 5 parts of sodium cellulose, 5 parts of ammonia water with a mass percentage of 25% to 28% and 5 parts of polyvinyl alcohol. Others are the same as in the first embodiment.

specific Embodiment approach 3

[0019] Specific embodiment three: the preparation method of a kind of modified urea-formaldehyde glue of the present embodiment is carried out according to the following steps: 1, weigh 600~700 parts by weight and be 37% formaldehyde, 35% by weight ~45 parts of melamine, 3~7 parts of p-chlorophenol, 3~7 parts of sodium cellulose, 3~7 parts of ammonia water of 25%~28% by mass and 3~7 parts of polyvinyl alcohol ;

[0020] 2. Add the formaldehyde with a mass percentage of 37% weighed in step 1 into the reactor, and heat up through the boiler. When the pressure of the boiler reaches 0.3MPa and the temperature of formaldehyde in the reactor reaches 30°C to 35°C, use A caustic soda solution with a concentration of 25% to 30% is used to adjust the pH of the formaldehyde to 7.5 to 8.0, and then add the sodium cellulose weighed in step 1;

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

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Abstract

The invention relates to a modified urea-formaldehyde glue and a preparation method thereof. The invention aims to solve the problems of poor stability and short storage time in the existing urea-formaldehyde glue. The urea-formaldehyde glue provided by the invention is prepared from formaldehyde, urea, melamine, parachlorophenol, sodium cellulose, ammonia water and polyvinyl alcohol. The preparation method comprises the following steps: 1. weighing the components, heating to 30-35 DEG C, regulating the pH value, and adding the sodium cellulose; 2. heating, and adding the first part of urea to regulate the pH value; 3. heating to 92 DEG C, regulating the pH value, and keeping the temperature to react; and 4. regulating the pH value, observing the reaction end, regulating the pH value to finish the reaction, adding the second part of urea, mixing, cooling to 70 DEG C, adding the third part of urea, adding the rest of components, cooling, regulating the pH value, and discharging the glue. The free formaldehyde content of the urea-formaldehyde glue is lower than 0.1%. The storage time is 2 months. The invention is applicable to the field of urea-formaldehyde glues.

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, and formaldehyde has the characteristics of strong volatility. The volatile gas is highly irritating to people and harmful to human health. Therefore, the study of low-toxicity urea-formaldehyde glue has become an urgent problem to be solved. In recent years, there have been related reports and researches. The use of a new type of modified urea-formaldehyde glue can make the content of free formaldehyde less than 0.5%. Low, thereby increasing the labor intensity, which is not conducive to the improvement of work efficiency, and the existing urea-formaldehyde glue has the danger of curing during the glue mixing process. For example, when the pH is lower than ...

Claims

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Application Information

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