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Urea formaldehyde resin for prepressing and synthesis technology thereof

A urea-formaldehyde resin, a synthesis process technology, applied in the direction of aldehyde/ketone condensation polymer adhesives, adhesive types, adhesives, etc., can solve the problems of high free aldehyde content, low initial viscosity, serious problems, etc., and achieve free aldehyde content Low, low toxicity, high initial viscosity effect

Inactive Publication Date: 2013-06-26
HUNAN FUXIANG WOOD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0002] During the processing of wood-based panels, in order to improve the quality of wood-based panels, pre-pressing is one of the essential processes. Most of the pre-pressing adhesives use ordinary urea-formaldehyde resins. The existing urea-formaldehyde resins have low initial viscosity and low free formaldehyde content. Higher, more serious environmental pollution

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0019] Take 80g of formaldehyde, put it into the reaction kettle, turn on the mixer, adjust the pH value to 8.2 with sodium hydroxide, then add the first batch of 50g of urea and 15g of polyvinyl alcohol, and heat to 45°C; within 40min, the temperature is evenly raised to 90°C , keep for 30min, and keep the pH value at 6.0; adjust the pH value to 4.8 with acetic acid, take a sample to measure the viscosity, when the measured value is 2.4 seconds, add the second batch of urea 50g, continue to react until the viscosity reaches 3.6 seconds, then add hydrogen immediately Sodium oxide and ammonia water adjust the pH value to 7.2, cool to 40°C and discharge.

Embodiment 2

[0021] Take 85g of formaldehyde, put it into the reaction kettle, turn on the mixer, adjust the pH value to 8.3 with sodium hydroxide, then add the first batch of 50g of urea and 17g of polyvinyl alcohol, heat to 47°C; within 47min, the temperature rises to 92°C evenly , keep for 35min, and keep the pH value at 6.5; use acetic acid to adjust the pH value to 4.9, take a sample to measure the viscosity, when the measured value is 2.5 seconds, add the second batch of urea 50g, continue the reaction until the viscosity reaches 3.7 seconds, then add hydrogen immediately Sodium oxide and ammonia water adjust the pH value to 7.3, cool to 42°C and discharge.

Embodiment 3

[0023] Take 90g of formaldehyde, put it into the reaction kettle, turn on the mixer, adjust the pH value to 8.4 with sodium hydroxide, then add the first batch of 50g of urea and 20g of polyvinyl alcohol, and heat to 50°C; within 50min, the temperature will be evenly raised to 95°C , keep for 40min, and keep the pH value at 7.0; adjust the pH value to 5.0 with acetic acid, take a sample to measure the viscosity, when the measured value is 2.6 seconds, add the second batch of urea 50g, continue to react until the viscosity reaches 3.8 seconds, then add hydrogen immediately Sodium oxide and ammonia water adjust the pH value to 7.5, cool to 45°C and discharge.

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PUM

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Abstract

The invention discloses urea formaldehyde resin for prepressing and a synthesis technology thereof. The urea formaldehyde resin comprises the following components: urea, formaldehyde, polyvinyl alcohol, sodium hydroxide, ammonia water and acetic acid. The synthesis technology of the urea formaldehyde resin for prepressing comprises the following steps of: adding the formaldehyde into a reaction kettle; starting a stirring machine; adjusting the pH value with sodium hydroxide; adding the first batch of urea and polyvinyl alcohol, and heating to 45-50 DEG C; uniformly increasing the temperature to 90-95 DEG C within 40-50 minutes; keeping the temperature for 30-40 minutes, and keeping the pH value at 6.0-7.0; adjusting the pH value with acetic acid to 4.8-5.0; sampling and measuring the viscosity; when the measured value is 2.4-2.6 seconds, adding the second batch of urea; continuously reacting until the viscosity reaches 3.6-3.8 seconds, adding the sodium hydroxide and the ammonia water to adjust the pH value to 7.2-7.5; and cooling to 40-45 DEG C and discharging. By adopting the technology disclosed by the invention, the prepared urea formaldehyde resin for prepressing has the characteristics of high initial viscosity, low content of free aldehyde and low toxicity.

Description

technical field [0001] The invention relates to a urea-formaldehyde resin for pre-pressing and a synthesis process. Background technique [0002] During the processing of wood-based panels, in order to improve the quality of wood-based panels, pre-pressing is one of the essential processes. Most of the pre-pressing adhesives use ordinary urea-formaldehyde resins. The existing urea-formaldehyde resins have low initial viscosity and low free formaldehyde content. higher, more serious environmental pollution. Contents of the invention [0003] The object of the present invention is to solve the problems in the prior art, thereby providing a urea-formaldehyde resin for pre-pressing with high initial viscosity, low content of free aldehyde and low toxicity and its synthesis process. [0004] The technical problem solved by the present invention is realized by the following technical scheme: a kind of urea-formaldehyde resin for pre-pressing, it is characterized in that: it is ...

Claims

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Application Information

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IPC IPC(8): C08L61/24C08G12/12C09J161/24
Inventor 刘建新陈东辉
Owner HUNAN FUXIANG WOOD
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