Production method for melamine modified urea-formaldehyde resin with low residual quantity of formaldehyde

A technology of melamine and urea-formaldehyde resin, which is applied in the direction of aldehyde/ketone condensation polymer adhesives, adhesive types, adhesives, etc., and can solve the problems of low degree of polymerization, residual monomers, inability to polymerize and supplement monomers, etc.

Active Publication Date: 2013-11-27
广西横州丽冠环保材料有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

There is a phenomenon in the polymerization reaction, called the gel phenomenon. The reason is that due to the high monomer concentration in the early stage of the polymerization reaction, the polymerization reaction is violent, the molecular weight of the polymer increases sharply, and the viscosity of the polymerization solution also increases sharply. Th

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0013] Pre-polymerization: add formaldehyde solution to the reaction kettle, adjust the pH value to 2 with formic acid, add 0.5% melamine by weight of formaldehyde solution, add urea with 8% weight of formaldehyde solution, heat up to 50°C, and keep warm for 30 minutes;

[0014] Polymerization: After pre-polymerization, add sodium hydroxide to the reaction solution, adjust the pH of the reaction solution to 8, add urea with 20% by weight of formaldehyde solution, and finish adding within 40 to 60 minutes, then add melamine with 1% by weight of formaldehyde solution, and heat up the reaction solution To 90 ~ 95 ℃, heat preservation reaction 90min.

[0015] Late stage of polymerization: after the end of the polymerization reaction, add urea with 50% weight of formaldehyde solution and finish adding within 40-60 minutes, then add melamine with 2.5% weight of formaldehyde solution, the reaction temperature drops to 70°C, and the reaction time is 90 minutes. After the reaction is c...

Embodiment 2

[0017] Pre-polymerization: add formaldehyde solution to the reaction kettle, adjust the pH value to 2.3 with formic acid, add 0.5% melamine by weight of formaldehyde solution, add urea with 10% weight of formaldehyde solution, heat up to 50°C, and keep warm for 30 minutes;

[0018] Polymerization: After pre-polymerization, add sodium hydroxide to the reaction solution, adjust the pH of the reaction solution to 8.3, add urea with 23% by weight of formaldehyde solution, and finish adding within 40 to 60 minutes, then add melamine with 1% by weight of formaldehyde solution, and heat up the reaction solution To 90 ~ 95 ℃, heat preservation reaction 90min.

[0019] Late stage of polymerization: after the end of the polymerization reaction, add urea with 45% weight of formaldehyde solution, and finish adding within 40-60 minutes, then add melamine with 2.5% weight of formaldehyde solution, the reaction temperature drops to 80°C, and the reaction time is 75 minutes. After the reactio...

Embodiment 3

[0021] Pre-polymerization: add formaldehyde solution to the reaction kettle, adjust the pH value to 2.5 with formic acid, add melamine with 0.5-0.6% of the weight of the formaldehyde solution, add urea with 10% of the weight of the formaldehyde solution, heat up to 50°C, and keep warm for 30 minutes;

[0022] Polymerization: After pre-polymerization, sodium hydroxide is added to the reaction solution to adjust the pH of the reaction solution to 8.5, urea with 25% by weight of formaldehyde solution is added, and the addition is completed within 40 to 60 minutes, then melamine with 1% by weight of formaldehyde solution is added, and the temperature of the reaction solution is raised To 90 ~ 95 ℃, heat preservation reaction 90min.

[0023] Late stage of polymerization: After the polymerization reaction is over, add urea with 40% weight of formaldehyde solution and finish adding within 40-60 minutes, then add melamine with 2.5% weight of formaldehyde solution, the reaction temperat...

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PUM

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Abstract

The invention provides a production method for a melamine modified urea-formaldehyde resin with low residual quantity of formaldehyde. Main raw materials used in the invention comprise formaldehyde, melamine and urea, wherein formaldehyde is fed in one step, and urea is fed in three steps. Production of the urea-formaldehyde resin comprises the three stages of prepolymerization, polymerization and later polymerization; the addition amounts of urea and reaction temperatures in each stage are different; the phenomenon of gelatinization is avoided in the process of polymerization by using the production method; the obtained urea-formaldehyde resin has narrow molecular weight distribution and low residual quantity of formaldehyde, is used for production of artificial boards and can reduce formaldehyde emission of the artificial boards.

Description

technical field [0001] The invention relates to a melamine-modified urea-formaldehyde resin with low residual formaldehyde content, and to an adhesive using the urea-formaldehyde resin as a raw material. Background technique [0002] Wood-based panels are boards or molded products made of wood or other non-wood plants as raw materials, separated into various unit materials by certain mechanical processing, and then glued with adhesives and other additives. The most commonly used adhesive for wood-based panels is urea-formaldehyde resin or modified urea-formaldehyde resin. The production process of urea-formaldehyde resin is simple and low in cost, but its water resistance and strength are low. Urea-formaldehyde resin modified by melamine, phenol or resorcinol, acrylate copolymer, isocyanate, polyvinyl alcohol or lignin significantly improves water resistance properties and bond strength. One of the raw materials for the production of urea-formaldehyde resin or modified ure...

Claims

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Application Information

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IPC IPC(8): C08G12/38C09J161/30
Inventor 肖文飞王飞虎邱金城农志军李同雨欧阳先明谢高专
Owner 广西横州丽冠环保材料有限公司
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