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

A technology of urea-formaldehyde resin glue and urea-formaldehyde resin, which is applied in application, adhesives, and other household appliances, etc., can solve problems such as difficulties in dry powder grinding and re-dissolving, changes in physical and chemical properties, and influence on bonding performance, so as to save water evaporation time and reduce Drying energy consumption, effect of improving bonding strength and water resistance

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 make the heat-sensitive liquid adhesive 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, which in turn affects the bonding. performance

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0036] Concentrate the thermosetting water-soluble urea-formaldehyde resin under a vacuum of 0.05MPa. During the concentration, the temperature of the adhesive is controlled at 20°C, concentrated to a solid content of 50%, and the pH value is adjusted to 5 with 20% phosphoric acid aqueous solution, and then vacuum freeze-dried. The concentrate is pre-frozen at -40°C until completely frozen; the sublimation drying section, the vacuum degree is 0.01mbar, and the freeze-drying temperature is -40°C; the analytical drying section, the vacuum degree is 0.001mbar, and the freeze-drying temperature is -80°C to obtain dry powder. The dry powder is ground by a nano ball mill at 80° 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 wood fiber is dried to a relative moisture content of 30%, and the application amount of the nano-powder is 5% of t...

Embodiment 2

[0040] Concentrate the thermosetting water-soluble urea-formaldehyde resin under a vacuum of 0.06MPa. During concentration, the temperature of the adhesive is controlled at 30°C, concentrated to a solid content of 60%, and the pH value is adjusted to 7 with 20% phosphoric acid aqueous solution, and then vacuum freeze-dried. The concentrate is pre-frozen at -45°C until it is completely frozen; the sublimation drying section, the vacuum degree is 0.02mbar, and the freeze-drying temperature is -45°C; the analytical drying section, the vacuum degree is 0.002mbar, and the freeze-drying temperature is -70°C to obtain dry powder. The dry powder is ground by a nano ball mill at 250° C. until the sieve value is 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 wood fiber is dried to a relative moisture content of 100%, and the application amount of the nano-powder i...

Embodiment 3

[0044] Concentrate the thermosetting water-soluble urea-formaldehyde resin under a vacuum of 0.07MPa. During the concentration, the temperature of the adhesive is controlled at 40°C, concentrated to a solid content of 70%, and the pH value is adjusted to 5.5 with 20% ammonium sulfate aqueous solution, followed by vacuum freeze-drying. 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 100°C until the sieve value is 700nm to obtain a nano powder. The nano-powder is applied to the wood shavings by air blowing. The nano-powder and the wood shavings are mixed evenly by mechanical stirring. The wood shavings are dried to a relative moisture content of 40%. calculate. After the sizing ...

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Abstract

The invention provides a preparation method of a thermosetting water-soluble urea-formaldehyde resin nanopowder adhesive. The preparation method comprises the following steps: 1, performing vacuum concentration on a thermosetting water-soluble urea-formaldehyde resin adhesive; 2, performing pH adjustment on the concentrated thermosetting water-soluble urea-formaldehyde resin adhesive; 3, performing vacuum freeze drying on the thermosetting water-soluble urea-formaldehyde resin adhesive after pH adjustment in the step 2; 4, grinding and screening after vacuum freeze drying. The adhesive prepared by the preparation method is applied to a high-water content artificial board substrate by dry gluing, and an artificial board is produced by a respiratory hot prepressing technology, so that the drying energy consumption of the artificial board substrate can be lowered and the curing speed, the gluing strength and the water resistance of the adhesive can be improved, and the amount of formaldehyde released from the artificial board can be reduced.

Description

technical field [0001] The invention relates to a preparation method of a thermosetting water-soluble urea-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] In 2015, the output of my country's wood-based panels reached 287 million cubic meters, accounting for 60% of the world's wood-based panel production, and the consumption of adhesives was 15.3 million tons. The consumption is still growing at a rate of about 10% with the increase of wood-based panel production. Among them, the consumption of urea-formaldehyde resin adhesives was 13.92 million tons (including urea-melamine-formaldehyde copolymer resin adhesives), accounting for nearly 90% of the consumption of wood-based panel adhesives. Urea-formaldehyde resin adhesive is the cheapest variety among all synthetic resins. It has long dominated the production of wood-based panels an...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C09J161/24C08J3/00C08J3/12C08J9/28B27N3/00B27N1/02B27N3/04B27N3/02B27N3/18B27D1/04C08L61/24
CPCB27D1/04B27N1/0209B27N3/002B27N3/02B27N3/04B27N3/18C08J3/00C08J3/12C08J9/28C08J2361/24C09J161/24
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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