Process for producing modified urea-formaldehyde resin, products produced thereby and uses thereof

A urea-formaldehyde resin and modification technology, which is applied in the direction of aldehyde/ketone condensation polymer adhesives, adhesive types, adhesives, etc., can solve problems such as life and health hazards, and the influence of urea-formaldehyde resin adhesive bond strength

Inactive Publication Date: 2009-04-08
张忠和
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

At the same time, in the traditional production of urea-formaldehyde resin, in order to ensure that the urea-formaldehyde resin has a higher cohesiveness, the usual practice is to use a larger molar ratio of urea: formaldehyde molar ratio, generally 1:1.1 ~ 1.5, the amount of formaldehyde is greater than the amount of urea, Because of the excessive amount of formaldehyde, there is still a lot of free formaldehyde in the product, and the formaldehyde released by the breakage of the methylene ether bond makes most of the wood-based panel products on the market today, because of the use of this urea-formaldehyde resin glue. , has brought great harm to people's life and health
Some existing environmentally friendly adhesives mainly reduce the amount of formaldehyde used in raw materials. However, formaldehyde is always greater than urea, and the molar ratio of formaldehyde continues to be reduced. The bond strength of the prepared urea-formaldehyde resin adhesive is greatly affected.

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0010] A preparation method of modified urea-formaldehyde resin, comprising the following specific steps:

[0011] The raw material molar ratio is urea: formaldehyde ≈ 1: 0.9, and the addition amount of the small molecular methyl silanol aqueous solution with a content of 12% is 4% of the total feed amount.

[0012] Add 1080 grams of formaldehyde into a three-necked flask, adjust the pH value to slightly alkaline (pH9) while stirring, add 400 grams of urea and stir evenly, then raise the temperature to 85-95 degrees within 1 hour, and keep warm for 30 minutes. Adjust the pH value to 4-5 for condensation reaction, add 78.4 grams of water-soluble methyl silanol (12% content, purchased from Hebei Jinzhou Zhonghe Decoration Material Factory, model JZ-2 moisture-proof agent). When the viscosity reaches 20 seconds (coat four cups, 30°C), add 240 grams of urea, keep warm for 30 minutes, adjust the pH to 9, and then add 240 grams of urea. After completely dissolving, cool down and dis...

Embodiment 2

[0015] The preparation process is the same as that of Example 1, except that the difference from Example 1 is that the aqueous solution of small molecular methyl silanol with a content of 12% is used, and the addition amount is 0.4% of the total feeding amount. Make modifications.

Embodiment 3

[0017] The preparation process is the same as that of Example 1, except that it is different from Example 1 in that: a 12% aqueous solution of small molecular methyl silanol is used, and the added amount is 10% of the total feed amount. Make modifications.

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Abstract

The invention relates to a method for preparing a modified urea resin. During the production process of urea resin, a small molecule methyl silanol aqueous solution which accounts for 0.4 percent to 30 percent of the total feeding amount by weight is added into raw material to carry out modification; or a small molecule methyl silanol aqueous solution with weight percentage of 0.4 percent to 30 percent is directly added into and mixed with the prepared urea resin. The method achieves the purpose of reducing formaldehyde release through changing the molecule structure and controlling the existence of free formaldehyde and methylene ether link and can also improve the resistance to water, weather and aging resistance and bonding strength of the urea resin.

Description

technical field [0001] The invention relates to a preparation method of modified urea-formaldehyde resin and its product and application. Background technique [0002] Urea-formaldehyde resin is currently the most widely used synthetic resin glue in the market, and it is mainly used in the bonding process of synthetic boards. Because of its low cost, it has always been valued by people. However, due to the defects of its own chemical structure, there are problems such as poor water resistance, low anti-aging performance, and especially the continuous release of formaldehyde. Today, people's awareness of environmental protection is constantly improving, and it is increasingly restricted by the market. Numerous scientific research workers have carried out a lot of work for this reason, have developed the environment-friendly type urea-formaldehyde resin glue of many varieties, have overcome the part shortcoming of urea-formaldehyde resin glue to a certain extent, but all can ...

Claims

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Application Information

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IPC IPC(8): C08G12/40C09J161/32
Inventor 张忠和
Owner 张忠和
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