Preparation method and application method of thermosetting water-soluble melamine-formaldehyde resin nano-powder adhesive

A melamine and formaldehyde resin technology, used in applications, adhesives, other household appliances, etc., can solve the problems of affecting the bonding performance, slow curing speed, and short active life of the adhesive, so as to improve the bonding strength and water resistance, and reduce formaldehyde. The effect of reducing the release amount and curing time

Active Publication Date: 2020-11-06
NANJING FORESTRY UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

This drying method will cause the liquid adhesive to continue to polycondense during the heating process, resulting in an increase in molecular weight and changes in physical and chemical properties. At the same time, the surface of the dried powder is hardened, making it difficult to grind and redissolve the dry powder, thereby affecting the bonding performance.
[0004] Ordinary melamine-formaldehyde resin adhesives usually have a high curing speed under acidic conditions, but if the glue is directly adjusted with acid or acid salt, the active period of the adhesive is extremely short when the pH value is low; when the pH value is high, The curing speed is slow, which cannot meet the actual production needs
Therefore, melamine-formaldehyde resin adhesives generally use latent curing agents to solve the problem of short active periods, but latent curing agents either need to be synthesized separately or are expensive

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0036]Concentrate the thermosetting water-soluble melamine-formaldehyde resin under a vacuum of 0.05MPa, control the temperature of the adhesive at 20°C during concentration, concentrate to a solid content of 50%, adjust the pH value to 5 with 20% phosphoric acid aqueous solution, vacuum freeze-dry, and concentrate The product was pre-frozen at -40°C until completely frozen; in the sublimation drying section, the vacuum degree was 0.01mbar, and the freeze-drying temperature was -40°C; in the analytical drying section, the vacuum degree was 0.001mbar, and the freeze-drying temperature was -80°C to obtain dry powder. The dry powder is ground by a nano ball mill at 120° C. to a sieve value of 900 nm to obtain a nano powder. The nano-powder is applied in the wood fiber by air blowing, the nano-powder and the wood fiber are mixed evenly by mechanical stirring, the relative moisture content of the wood fiber is 30%, and the application amount of the nano-powder is calculated as 5% of...

Embodiment 2

[0040] Concentrate the thermosetting water-soluble melamine-formaldehyde resin under a vacuum of 0.06MPa, control the temperature of the adhesive at 30°C during concentration, concentrate to a solid content of 60%, adjust the pH value to 3 with 20% phosphoric acid aqueous solution, vacuum freeze-dry, and concentrate The product was pre-frozen at -45°C until completely frozen; in the sublimation drying section, the vacuum degree was 0.02mbar, and the freeze-drying temperature was -45°C; in the analytical drying section, the vacuum degree was 0.002mbar, and the freeze-drying temperature was -70°C to obtain dry powder. The dry powder is ground by a nano ball mill at 280° C. to a sieve value of 400 nm to obtain a nano powder. The nano-powder is applied in the wood fiber by air blowing, the nano-powder and the wood fiber are mixed evenly by mechanical stirring, the relative moisture content of the wood fiber is 100%, and the application amount of the nano-powder is calculated as 20%...

Embodiment 3

[0044] Concentrate the thermosetting water-soluble melamine-formaldehyde resin under a vacuum of 0.07MPa, control the temperature of the adhesive at 40°C during concentration, concentrate to a solid content of 70%, adjust the pH value to 4.5 with 20% ammonium sulfate aqueous solution, and then vacuum freeze-dry. The concentrate is pre-frozen at -50°C until it is completely frozen; the sublimation drying section, the vacuum degree is 0.03mbar, and the freeze-drying temperature is -50°C; the analytical drying section, the vacuum degree is 0.003mbar, and the freeze-drying temperature is -60°C to obtain dry powder. The dry powder is ground by a nano ball mill at 240° C. until the sieve value is 700 nm to obtain a nano powder. The nano-powder is applied in the wood shavings by air blowing. The nano-powder and the wood shavings are mixed evenly by mechanical stirring. The relative moisture content of the wood shavings is 30%. . After the sizing and shavings are paved, they enter th...

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Abstract

The invention provides a preparation method of a thermosetting water-soluble melamine formaldehyde resin nano-powder adhesive, and the preparation method includes the following steps: step 1, vacuum concentration of a thermosetting water-soluble melamine formaldehyde resin adhesive; step 2, adjusting of the pH value of the concentrated thermosetting water-soluble melamine formaldehyde resin adhesive; step 3, vacuum freeze-drying of the thermosetting water-soluble melamine formaldehyde resin adhesive with the pH value adjusted in the step 2; step 4, grinding and screening after the vacuum freeze-drying. The adhesive prepared by the method is applied to an artificial board base material with high moisture content by dry sizing. A respirable hot pre-pressing process is used to produce an artificial board, the drying energy consumption of the artificial board can be reduced, the curing speed, bonding strength and water resistance of the adhesive can be improved, and the formaldehyde emission of the artificial board can be reduced.

Description

technical field [0001] The invention relates to a preparation method of a thermosetting water-soluble melamine-formaldehyde resin nano-powder adhesive and an application method in the production of wood-based panels, belonging to the field of wood-based panel manufacturing. Background technique [0002] Melamine-formaldehyde resin adhesive has excellent characteristics such as high bonding strength, strong boiling water resistance, and good thermal stability. However, the water-soluble melamine-formaldehyde resin adhesive has shortcomings such as short storage period, short active period, and slow curing speed. It must be modified by adding various ingredients before it can be used normally in the wood-based panel industry. In addition, it has defects such as formaldehyde release and low moisture content requirements for bonding substrates, which limit its application in the wood-based panel industry. [0003] The general spray drying is a kind of suspended particle process...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C09J161/28B27N3/00B27N3/08
CPCB27N3/002B27N3/08C09J161/28
Inventor 韩书广崔举庆甘露徐德良丁涛王华徐朝阳
Owner NANJING FORESTRY UNIV
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