Preparation method of radiation-modified melamine urea-formaldehyde resin

A melamine urea-formaldehyde resin modification technology, which is applied in the manufacture of tools, wood treatment, wood processing equipment, etc., can solve the problems of damaged wood substrates, high molecular weight of urea-formaldehyde resin, and insignificant improvement of the mechanical properties of finished impregnated wood, etc., to achieve The effect of reducing molecular weight and reducing formaldehyde emission

Active Publication Date: 2021-08-13
同威信达技术(江苏)股份有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Due to the cross-linking characteristics of melamine, it is easy to make the molecular weight of urea-formaldehyde resin larger in the glue-making stage, resulting in a low impregnation rate for slightly thicker wood, so that the mechanical properties of the finished impregnated wood are not significantly improved or require high-pressure production equipment.
The use of some current physical or chemical methods to improve wood impregnation can easily cause damage to the wood substrate, and it is still impossible to avoid the problem of uneven impregnation caused by the high molecular weight of the glue and difficulty in entering the solid wood. Therefore, reducing the molecular weight of the glue is essentially the best. effective method

Method used

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Examples

Experimental program
Comparison scheme
Effect test

preparation example Construction

[0021] A preparation method of radiation-modified melamine urea-formaldehyde resin, comprising the following steps:

[0022] S1, putting the sawn wood blocks into a kiln for drying until the moisture content is 7-12%, and leaving the kiln for later use;

[0023] S2, the melamine urea-formaldehyde resin impregnation solution is placed in a strong radiation source for irradiation, wherein the radiation dose rate is 1-100 kGy / s, and the total radiation dose is 10-100 kGy;

[0024] S3, adding the dried wood block into the melamine urea-formaldehyde resin impregnating solution obtained in step S2;

[0025] S4, the preform obtained in step S3 is dried at 50-120 degrees Celsius for 20-200 hours isothermally or with gradient temperature increase to finally obtain a finished product.

[0026] As a further improvement, in step S2, the preparation method of the melamine urea-formaldehyde resin impregnation solution comprises the following steps:

[0027] S21, after mixing 900 to 1200 p...

Embodiment 1

[0033] Put the wood block after sawing the log into the kiln for drying, and dry it to a moisture content of 7-12%, and leave the kiln for subsequent use; mix 900 parts by weight of 37wt% formaldehyde solution, 4 parts by weight of 10wt% sodium hydroxide solution and After adding 400 parts by weight of urea and mixing, adjust the temperature to 90°C, and react at a constant temperature for 1 hour; maintain a constant temperature reaction temperature of 80°C, then add 150 parts by weight of urea, 20 parts by weight of melamine, and 90 parts by weight of maltodextrin, React for 1 hour, drop to room temperature and discharge; place the prepared melamine formaldehyde resin solution in an artificial x-ray source for irradiation with a radiation dose rate of 10kGy / s, and a total radiation dose of 40kGy; put the wood block into a pressurized impregnation In the tank, first vacuumize to -0.01MPa, vacuumize for 0.5 hours, then open the valve to impregnate the glue, pressurize to 0.5MPa ...

Embodiment 2

[0035] Put the wood block after sawing the log into the kiln for drying, and dry it to a moisture content of 7-12%, and leave the kiln for standby; 1000 parts by weight of 37wt% formaldehyde solution, 6 parts by weight of 10wt% sodium hydroxide solution and After adding 450 parts by weight of urea and mixing, adjust the temperature to 90°C, and react at a constant temperature for 1 hour; keep a constant temperature reaction temperature of 80°C, then add 150 parts by weight of urea, 20 parts by weight of melamine, and 100 parts by weight of maltodextrin, React for 1.2 hours, drop to room temperature and discharge; place the prepared melamine formaldehyde resin solution in an electron beam radiation source for irradiation with a radiation dose rate of 10kGy / s and a total radiation dose of 50kGy; put the wood block into a pressurized impregnation In the tank, first vacuumize to -0.01MPa, vacuumize for 0.5 hours, then open the valve to impregnate the glue, pressurize to 1MPa throug...

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Abstract

The invention provides a method for preparing radiation-modified melamine urea-formaldehyde resin, which includes the following steps: S1, put the wood block after sawing the log into a kiln for drying, and dry it until the moisture content is 7-12%, and take it out of the kiln for later use ; S2, the melamine urea-formaldehyde resin impregnation solution is placed in a strong radiation source for irradiation, wherein the radiation dose rate is 1-100 kGy / s, and the total radiation dose is 10-100 kGy; S3, adding the dried wood blocks into step S2 Immerse in the obtained melamine urea-formaldehyde resin impregnating solution; S4, the preform obtained in step S3 is dried at 50-120 degrees Celsius isothermally or at a gradient temperature for 20-200 hours, and finally a finished product is obtained.

Description

technical field [0001] The invention relates to a preparation method of radiation-modified melamine urea-formaldehyde resin. Background technique [0002] Urea-formaldehyde resin refers to the medium-molecular-weight water-based resin produced by the reaction of urea and formaldehyde. Due to its low price, it has been widely used in the field of wood-based panels. However, the formaldehyde emission of this type of glue is often difficult to reach the national standard E1 level, so it has been There are various formaldehyde scavengers to modify urea-formaldehyde glue, but it is often easy to reduce the mechanical properties of glue composites. Modification with melamine can effectively reduce the amount of formaldehyde released, and can also provide three-dimensional cross-linking to strengthen the final mechanical properties of the finished product , so the appropriate addition of melamine-modified urea-formaldehyde glue is an effective glue modification method that has been...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C08G12/40C08G12/38C08J3/28B27K3/04B27K5/04C08L61/32
CPCB27K3/04B27K5/04C08G12/38C08G12/40C08J3/28C08J2361/32
Inventor 张明昕韩志伟胡涛宋烨覃怀莉孟薇
Owner 同威信达技术(江苏)股份有限公司
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