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Urea-formaldehyde resin and urea-formaldehyde resin glue and preparation method thereof

The technology of urea-formaldehyde resin glue and urea-formaldehyde resin is applied in the field of adhesives for wood-based panels and the preparation thereof, and the method is simple and easy to implement, easy to popularize, and the effect of preventing the problem of excessive aging is achieved.

Inactive Publication Date: 2008-04-30
BEIJING FORESTRY UNIVERSITY
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0004] One object of the present invention is to provide a kind of urea-formaldehyde resin for plywood and its preparation method in view of the above problems, the urea-formaldehyde resin is added with superabsorbent resin in the synthesis process, effectively preventing the aging of glued veneer in the production of plywood Excessive, to ensure that even if the glued veneer is aged for a long time under the condition of strong wind and low humidity, there will be no poor pre-pressing effect of the slab and glue opening after hot pressing of the plywood

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0021] 1. The molar ratio of formaldehyde and urea is 1.2:1, and the superabsorbent resin is 1% of the total weight of formaldehyde and urea.

[0022] 2. Add 37% formaldehyde solution into the reaction kettle, and adjust the pH value to 7.5-8.5 with sodium hydroxide solution while stirring.

[0023] 3. Add the first batch of urea U1 and all the superabsorbent resin, so that the molar ratio of formaldehyde to urea is 2.0:1, within 30-60 minutes, slowly raise the temperature to 90±℃, and keep warm for 40-60 minutes;

[0024] 4. Adjust the pH value to 4.2-4.8 with formic acid. React until the viscosity is Tu-4 cup for 22-30 seconds (25°C);

[0025] 5. Immediately adjust the pH value to 7.0-7.5 with sodium hydroxide solution, add the second batch of urea U2, make the molar ratio of formaldehyde to urea 1.6:1, and react at 70-80°C for 30-60 minutes;

[0026] 6. Add the remaining amount of urea U3 and react at 60-70°C for 30-60 minutes;

[0027] 7. Cool down to below 40°C and dis...

Embodiment 2

[0037] 1. The molar ratio of formaldehyde and urea is 1.4:1, and the superabsorbent resin is 0.5% of the total weight of formaldehyde and urea.

[0038] 2. Add 37% formaldehyde solution into the reaction kettle, and adjust the pH value to 7.5-8.5 with sodium hydroxide solution while stirring;

[0039] 3. Add urea U1 for the first time, so that the molar ratio of formaldehyde and urea is 2.0:1, within 30-60 minutes, slowly raise the temperature to 90±℃, and keep warm for 40-60 minutes;

[0040] 4. Adjust the pH value to 4.2-4.8 with formic acid. React until the viscosity is Tu-4 cup for 22-30 seconds (25°C);

[0041] 5. Immediately use sodium hydroxide solution to adjust the pH value to 7.0-7.5, add the second urea U2 and all the superabsorbent resin, so that the molar ratio of formaldehyde to urea is 1.6:1, and react for 30-60 minutes at 70-80°C ;

[0042] 6. Add the remaining amount of urea U3, so that the molar ratio of formaldehyde and urea is 1.4:1, and react at 60-70°C...

Embodiment 3

[0053] 1. The molar ratio of formaldehyde and urea is 1.8:1, and the superabsorbent resin is 0.01% of the total weight of formaldehyde and urea.

[0054] 2. Add 37% formaldehyde solution into the reaction kettle, and adjust the pH value to 7.5-8.5 with sodium hydroxide solution while stirring.

[0055] 3. Add urea U1 for the first time, so that the molar ratio of formaldehyde and urea is 2.0:1, within 30-60 minutes, slowly raise the temperature to 90±℃, and keep warm for 40-60 minutes;

[0056] 4. Use formic acid to adjust the pH value to 4.2-4.8, and react until the viscosity is Tu-4 cup for 22-30 seconds (25°C);

[0057]5. Immediately adjust the pH value to 7.0-7.5 with sodium hydroxide solution, add the remaining amount of urea U2 and superabsorbent resin to make the molar ratio of formaldehyde to urea 1.8:1, and react at 60-70°C for 30-60 minutes.

[0058] 6. Cool down to below 40°C and discharge.

[0059] Resin quality index:

[0060] Solid content 45-55%

[0061] pH ...

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Abstract

This invention is a preparation method of urea formaldehyde condensate used in glued board. By adding 0.01-1% high-hydroscopicity resin of formaldehyde and aquacare's total weight, we successfully prevent glued board from overaging. It could guarantee high glue efficiency even after long-time aging. It hardly change the original process, and it's still lower-cost.

Description

technical field [0001] The invention relates to an adhesive for wood-based panels and a preparation method thereof, in particular to a urea-formaldehyde resin for plywood and a preparation method thereof, urea-formaldehyde resin glue and a preparation method thereof. Background technique [0002] At present, the adhesive used by most wood-based panel manufacturers is urea-formaldehyde resin. The urea-formaldehyde resin used by most manufacturers is produced by the process of "weak base-weak acid-weak base". The main raw materials are urea and formaldehyde. Vinyl alcohol is used to improve the initial viscosity (pre-compression), and curing agent (commonly used ammonium chloride), filler (commonly used flour in plywood production) and so on are often added before use. [0003] There are now thousands of plywood manufacturers in our country, among which small and medium-sized factories for manual paving and billet assembly account for the majority. Due to limited production ...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C08G12/12C09J161/24B27D1/04
Inventor 李建章周文瑞董金宝陈欣张德荣母军任强赵强
Owner BEIJING FORESTRY UNIVERSITY
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