Environmental protection urea-formaldehyde resin and preparation method thereof

An environmentally friendly urea-formaldehyde resin, a new type of technology, applied in adhesive types, aldehyde/ketone condensation polymer adhesives, adhesives, etc., can solve problems such as low bonding strength, low molar ratio urea-formaldehyde resin, poor storage stability, and poor water resistance. , to achieve the effect of low free formaldehyde content, high bonding strength and low cost

Inactive Publication Date: 2008-09-17
BEIJING UNIV OF CHEM TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0004] The purpose of the present invention is to solve the problems of poor storage stability, low bonding strength and poor water resistance of current low molar ratio urea-formaldehyde resins, and provide a preparation method and application of a new type of environmentally friendly urea-formaldehyde resin adhesive

Method used

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  • Environmental protection urea-formaldehyde resin and preparation method thereof
  • Environmental protection urea-formaldehyde resin and preparation method thereof
  • Environmental protection urea-formaldehyde resin and preparation method thereof

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0017] In a 500ml four-necked bottle equipped with a reflux condensing device and a stirring device, add 194.5 g of formaldehyde aqueous solution, 94 g of urea, and 1.2 g of pH buffer borax, turn on the stirring device, add an alkaline catalyst dropwise to adjust the pH of the system to 9.0, and start heating at the same time ;When the temperature rises to 85°C, keep warm for half an hour; adjust the pH of the system to 4.8 with an acid catalyst, and react for 10 minutes; add the remaining 28g of urea, and react for 5 minutes; cool down to 75°C, add 15g of glutaraldehyde, and keep warm for 15 minutes; cool down to 40°C, add a pH buffering agent to adjust the pH of the system to 8.0, cool and discharge to obtain a urea-formaldehyde resin glue. The total molar ratio of formaldehyde and urea in this system is 1.2:1, the F / U molar ratio is controlled to be 1.8:1 in the initial addition stage, and the reaction time is 2 hours. The specific properties of the resin are shown in Table...

Embodiment 2

[0019] In this embodiment, glyoxal is used to modify the resin, and the addition amount is 15 g, and the others are the same as in Example 1. Because the glyoxal solution has strong acidity, it can promote the condensation of the resin, and the obtained product has a high viscosity and a high degree of crosslinking, but the storage stability period is shorter than that of Example 1.

Embodiment 3

[0021] In this embodiment, malondialdehyde is used to modify the resin, and the addition amount is 15 g, and the others are the same as in Example 1.

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Abstract

A novel environmental protective urea-formaldehyde resin and a preparation method belong to the field of wood processing adhesives. The urea-formaldehyde resin is formed by the reaction of urea, formaldehyde, aldehyde, one or more stabilizers and modifier according to the route of weak base-weak acid-weak base. The method firstly controls the F / U feed ratio, the pH value and the temperature during the reaction process to reduce the content of free formaldehyde in the resin; then the aldehyde is introduced to allow the resin to generate the stable alkyl ether (-(CH2)n-O-(CH2)n-) structure, thus reducing the content of methylene-ether bond (-CH2-O-CH2-) in the resin structure, simultaneously reducing the using amount of the formaldehyde and further greatly reducing the release amount of the formaldehyde during the using process of a plate from the two aspects; in addition, the introduction of a long chain and polyaldehyde can ensure the resin to have great bonding strength and water resistance. The urea-formaldehyde resin which is prepared by the invention has the advantages of low content of free formaldehyde, simple process, low cost, etc., the release amount of the formaldehyde of the plate which is prepared by using the adhesive achieves the E0 level standard, and the high bonding strength can be maintained after being boiled in hot water.

Description

technical field [0001] The invention relates to a preparation method and application of a novel environment-friendly urea-formaldehyde resin, belonging to adhesives required for wood processing. Background technique [0002] At present, the total output of wood-based panels in my country has exceeded 70 million m 3 , with an average annual growth rate of more than 10%, has become the world's largest wood-based panel producer, and the annual consumption of adhesives for wood-based panel production (100% solid content) has exceeded 4 million tons. Urea-formaldehyde resin has the advantages of good initial bonding strength, fast curing, light color, no pollution to wood, high bonding strength, and convenient use. It has been widely used in interior decoration and other aspects. It is currently the most used type of adhesive, accounting for more than 80% of the amount of glue used in wood-based panels. Especially its low price makes it difficult to be replaced by other types of...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C08G12/36C08G12/38C08G14/08C08G12/46C09J161/28C09J161/30C09J161/34C09J161/32
Inventor 李效玉叶俊王海侨
Owner BEIJING UNIV OF CHEM TECH
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