Urea-formaldehyde resin powder formula and production process

Thermosetting resin obtained by polycondensation of urea and formaldehyde. Urea-formaldehyde resin has low cost, light color, high hardness, oil resistance, mildew resistance, good insulation and temperature resistance, but poor weather resistance and water resistance. It was one of the earlier thermoset resins to be developed.

1: Basic formula of urea-formaldehyde resin powder (weight/kg)

Liquid formic acid (content not less than 85%): appropriate amount of liquid caustic soda (concentration 36%): appropriate amount of industrial
Urea (nitrogen content not less than 46%): 100 formaldehyde: 256 formaldehyde adsorbent: the amount is free formaldehyde
15- -20% of aldehydes.

2： the production of urea-formaldehyde resin powder

1. Put the metered formaldehyde into the reaction kettle.
2. Under constant stirring, add the caustic soda solution to the formaldehyde, adjust the pH value to 7.8, and start slowly
3. Under constant stirring, add 50% of the total amount of urea (pulverized into powder) into the reaction kettle,
And heat up to 60 ℃ in 30 minutes (about 10 ℃ of temperature rises every 10 minutes).
4. When the temperature in the reactor reaches 60°C, add 25% of the urea for the second time, and also keep stirring.
Stir, and control the heating rate as before, and control the temperature to rise to 90 ° C within 30 minutes.
5. Finally, add the remainder of urea and keep at 90°C for 30 minutes.
6. Adjust the pH value to 4.5 with liquid caustic soda (concentration 36%) after the constant temperature. Attention should be paid to the acid adjustment.
Its natural exothermic reaction, if this is the case, the temperature should be rapidly cooled so as not to affect the quality of the rubber compound.
7. Within 10-20 minutes after acid adjustment, use normal temperature water to check whether the rubber compound reaches the reaction end point.
The glue that reaches the end point of the reaction will form a white mist when it is poured into the clean water. If the reaction end point has been reached, the temperature is immediately lowered to about 75°C, the pH value is adjusted to 7.8 with caustic soda, and the gel is formed at a constant temperature. This constant temperature stage is also a dehydration stage, and the length of dehydration time depends on the requirements for the concentration of the glue.
8. Check the next steps to visit: “Urea-formaldehyde resin adhesive”

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