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Preparation method of modified urea-formaldehyde resin with improved storage stability

A technology of storage stability and urea-formaldehyde resin, which is applied in the direction of aldehyde/ketone condensation polymer adhesives, adhesive types, adhesives, etc., can solve the problems of urea-formaldehyde resin storage stability and high formaldehyde release of urea-formaldehyde resin. Achieve the effect of reducing free formaldehyde content, reducing formaldehyde emission and good storage stability

Active Publication Date: 2014-04-02
南京雪郎化工科技有限公司
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

Although the free formaldehyde content of the urea-formaldehyde resin obtained by the above-mentioned method can be greatly reduced, the formaldehyde emission of the urea-formaldehyde resin obtained by the above-mentioned method is still relatively high, and it generally needs to be mixed with urea on site before use, and the urea-formaldehyde resin obtained by the above-mentioned method The storage stability of the resin needs to be improved

Method used

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  • Preparation method of modified urea-formaldehyde resin with improved storage stability

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preparation example Construction

[0010] According to the preparation method of a modified urea-formaldehyde resin with improved storage stability provided by the present invention, the method comprises:

[0011] (1) The first batch of urea, modifier and formaldehyde are subjected to the first contact reaction until the water miscibility is 0.4 to 1.5 times, and the molar ratio of formaldehyde: the first batch of urea to the total amount of modifier is 1 to 1.7 : 1;

[0012] (2) Carry out the second contact reaction of the obtained mixture with the second batch of urea at a temperature of 60±10° C. for 1 to 30 minutes, formaldehyde: the molar ratio of the first batch of urea, the second batch of urea and the total amount of the modifying agent is 0.6~1.25:1;

[0013] (3) Adjust the pH value of the mixture obtained in step (2) to 8.5-10 and lower the temperature to below 40°C.

[0014] According to the present invention, the weight ratio of the first batch of urea: the second batch of urea is 0.5-10:1, prefer...

Embodiment 1

[0028] This example is used to illustrate the preparation method of the modified urea-formaldehyde resin with improved storage stability provided by the present invention.

[0029] 416.67 grams of concentration is 36% by weight of formalin (formaldehyde is 5 moles) to join in 1000 milliliters of reactors, with concentration is the sodium hydroxide aqueous solution of 20% by weight that the initial pH value of formalin is adjusted to 8.2, and heated to 50°C, then added 151.67g of urea, 61.25g of melamine and 1.75g ​​of polyvinyl alcohol under stirring conditions, raised the temperature to 90°C and stirred at this temperature for 15 minutes, and used during stirring The aqueous solution of triethanolamine with a concentration of 30% by weight maintained the pH of the reaction system at 8.2.

[0030] Then the temperature of the reaction is reduced to 85° C., and the pH value of the reaction system is adjusted to 5.0 with a concentration of 10% by weight aqueous formic acid, and t...

Embodiment 2

[0040] This example is used to illustrate the preparation method of the modified urea-formaldehyde resin with improved storage stability provided by the present invention.

[0041] 416.67 grams of concentration is 36% by weight of formalin (formaldehyde is 5 moles) to join in 1000 milliliters of reactors, with concentration is the sodium hydroxide aqueous solution of 20% by weight to make the formalin (formaldehyde) solution initial Adjust the pH value to 7.5 and heat to 45°C, then add 151.67 grams of urea, 61.46 grams of melamine and 1.54 grams of polyvinyl alcohol under stirring, raise the temperature to 90°C and stir at this temperature for 15 minutes, and During the process, an aqueous solution of triethanolamine with a concentration of 30% by weight was used to adjust and maintain the pH at 7.5.

[0042] Then the reaction temperature is reduced to 80°C, and the pH value of the reaction system is adjusted to 4.4 with a 10% by weight aqueous formic acid solution, and the st...

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Abstract

A preparation method of a modified urea-formaldehyde resin with improved storage stability. The method comprises the following steps: (1) subjecting a first batch of urea, a modifier and formaldehyde to a first contact reaction until water miscibility reaches 0.4-1.5 times, wherein a molar ratio of the first batch of urea to a total weight of formaldehyde and modifier is 1-1.7:1; (2) subjecting the obtained mixture and a second batch of urea to a second contact reaction at a temperature of 60+ / -15 DEG C for 1-30min, wherein a molar ratio of formaldehyde urea to a total weight of the first batch of urea, the second batch of urea and modifier is 0.6-1.25:1; and (3) adjusting the pH value of the mixture obtained in the step (2) to 8.5-10 and cooling to lower than 40 DEG C. The modified urea-formaldehyde resin with improved storage stability prepared by the method provided by the invention has good storage stability and reduced free formaldehyde content, so that a veneer board prepared from the modified urea-formaldehyde resin with improved storage stability has decreased formaldehyde release quantity and free formaldehyde content; and the formaldehyde release quantity further satisfies the regulations in national standard E1 (<=1.5 mg / L).

Description

technical field [0001] The invention relates to a preparation method of modified urea-formaldehyde resin with improved storage stability. Background technique [0002] Urea-formaldehyde resins, especially melamine-modified urea-formaldehyde resins (MUF), are widely used in the wood manufacturing industry for bonding wood or as adhesives in the production of wood-based materials, such as for particleboard, plywood and various fiberboards. in production. Urea-formaldehyde resin is the reaction product of urea and formaldehyde. Because the water resistance and intensity of this urea-formaldehyde resin are relatively poor, therefore generally use urea-formaldehyde resin modifier to modify the urea-formaldehyde resin of gained, to obtain modified urea-formaldehyde resin such as commonly used melamine-modified urea-formaldehyde resin (MUF), The water resistance and strength of this urea-formaldehyde resin are significantly higher than that of unmodified conventional urea-formald...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C08G12/40C09J161/32
Inventor 秦特夫李改云黄洛华
Owner 南京雪郎化工科技有限公司