Modified urea-formaldehyde glue and preparation method thereof

A technology for modifying urea-formaldehyde and urea-formaldehyde adhesives, which can be used in adhesives, aldehyde/ketone condensation polymer adhesives, unsaturated alcohol copolymer adhesives, etc. The effect of saving work efficiency, improving initial viscosity and improving stability

Inactive Publication Date: 2012-08-01
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 me

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-cresol, 3-7 parts of cellulose sodium, 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 added p-cresol can further increase the hot water property of the glue and reduce the free formaldehyde content to a very low value. In the urea-formaldehyde glue of this embodiment Free 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 the glue, enable the urea-formaldehyde glue to rea...

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 5 parts of p-cresol, 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-cresol, 3~7 parts of sodium cellulose, 3~7 parts of ammonia water with a mass percentage of 25%~28% and 3~7 parts of polyethylene 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 wi...

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Abstract

The invention relates to modified urea-formaldehyde glue and a preparation method thereof. The invention aims to solve the problems that traditional urea-formaldehyde glue is low in stability and is short in storage time. The urea-formaldehyde glue consists of formaldehyde, urea, tripolycyanamide, p-methylphenol, sodium cellulosate, ammonia water and polyvinyl alcohol. The preparation method comprises the following steps of: I-, weighing all components, heating to 30-35 DEG C, regulating a pH value and adding the sodium cellulosate; II-, heating, adding the first part of urea to regulate the pH value; III-, heating to 92 DEG C, regulating the pH value and then performing thermal insulation reaction; and IV-, regulating the pH value, observing the end point of the reaction; regulating the pH value to end the reaction; adding the second part of urea; mixing; cooling to 70 DEG C; adding the third part of urea; then, adding the residual components; cooling; regulating the pH value; and putting glue to obtain the modified urea-formaldehyde glue. The free formaldehyde content of the urea-formaldehyde glue is lower than 0.1 percent. The storage time is 2 months. The invention is applied to the field of the urea-formaldehyde glue.

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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IPC IPC(8): C09J161/34C09J101/26C09J129/04
Inventor 王阳毛桂洁张宇张华张冬梅刘振久王勇战
Owner HEILONGJIANG UNIV
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