Method for improving etherification degree of hexa-methoxy methyl melamine resin

A technology of hexamethoxymethyl melamine and hexamethylol melamine is applied in the field of reducing the water content in the etherification reaction system, and can solve the problems such as the inability to change the equilibrium point of the chemical reaction, the uneconomical recovery amount, the influence of the reaction rate, and the like. The effect of prolonging the storage period, reducing the amount of water and improving the quality of the resin

Active Publication Date: 2010-04-21
JIANGSU GUOLI CHEM TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

In a chemical reaction, although the reaction efficiency can be improved by using a catalyst, the catalyst can only affect the reaction rate and cannot change the equilibrium point of the chemical reaction.
[0014] In addition, there is also the use of increasing the amount of methanol input to increase the degree of etherification, but the increase in the amount of input is also limited, otherwise it is very uneconomical (increasing the amount of methanol input needs to increase the recovery of methanol, thereby increasing energy consumption and also increased loss of methanol)
[0015] Although the existing technology can improve the degree of etherification to a certain extent, there are still many unsatisfactory situations, so there is still room for improvement

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0026] Example 1: Add 250 g (0.816 mol) of hexamethylol melamine, 200 g methylal (2.63 mol) and 300 g methanol (9.36 mol) into a 1000 ml reaction flask with a stirrer and a reflux condenser. Start stirring, adjust the pH to 3.0 with sulfuric acid, then slowly raise the temperature to 50°C, keep stirring for 40 minutes after the material in the kettle is transparent, and then add liquid alkali to adjust the pH to 8.5. Raise the temperature and steam to remove methylal, methanol, and moisture, and the recovered methylal and methanol can be reused after rectification. When the temperature reaches 90°C, start the vacuum system and continue to heat up. When it reaches 110°C, continue to stir and keep warm for 30 minutes, then cool to 90°C and filter while hot to obtain 317.7g of the product, of which 98.6% non-volatile matter, viscosity 2700cps / 25°C , chromaticity (APHA) 21, etherification degree 5.86.

Embodiment 2

[0027]Example 2. Add 250 g of paraformaldehyde and 200 g of methanol to a 1000 ml reaction flask with a stirrer and a reflux condenser, start stirring, adjust the pH to 8.5 with sodium hydroxide, heat up to 68° C., and keep stirring for 30 minutes Continue to heat up to 80°C, and continue to heat and stir for 30 minutes after the material is transparent, then cool to 70°C. Then add 100 g of methanol and 103 g (0.816 mol) of melamine, stir and raise the temperature to 75° C., continue to keep stirring for 4 hours, and then cool to 45° C. Then add 200g (2.63mol) of methylal, adjust the pH to 3.0 with sulfuric acid, then slowly raise the temperature to 50°C, keep stirring for 40 minutes after the material in the kettle is transparent, and then add liquid alkali to adjust the pH to 8.5. Raise the temperature and steam to remove methylal, methanol, and moisture, and the recovered methylal and methanol can be reused after rectification. When the temperature reaches 90°C, start the ...

Embodiment 3

[0028] Example 3: Add 250 g (0.816 mol) of hexamethylol melamine, 300 g methylal (3.94 mol) and 300 g methanol (9.36 mol) into a 1500 ml reaction flask with a stirrer and a reflux condenser. Start stirring, adjust the pH to 3.0 with sulfuric acid, then slowly raise the temperature to 46°C, keep stirring for 60 minutes after the material in the kettle is transparent, and then add liquid alkali to adjust the pH to 8.5. Raise the temperature and steam to remove methylal, methanol, and moisture, and the recovered methylal and methanol can be reused after rectification. When the temperature reaches 90°C, start the vacuum system and continue to heat up. When it reaches 110°C, continue to stir and keep warm for 30 minutes, then cool to 90°C and filter while hot to obtain 317.9g of product, of which 98.6% non-volatile matter, viscosity 2760cps / 25°C , chromaticity (APHA) 24, etherification degree 5.86.

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Abstract

The invention relates to a method for improving the etherification degree of hexa-methoxy methyl melamine resin, which is characterized in that methylal is added during the etherification, wherein the mole ratio of the methylal to hexamethylolmelamine is 0.5-10:1. The methylal reacts with carbinol and formaldehyde, water generated during system etherification can be reduced, so that the etherification can be conducted to facilitate the generation of ethers, and the etherification degree is greatly improved. By adopting the method, the etherification degree can be improved to 5.23 from original 4.83 and the resin quality can also be improved; in addition, the water reduction in a flushing system can influence and lessen the polycondensation among molecules to cause the reduction of the viscosity of products, thus the property of hexa-methoxy methyl melamine resin (HMMM resin) can be improved greatly; for instance, the invention is beneficial to prolonging the storage term of prepared coating and improving the bond property with rubber.

Description

technical field [0001] The invention relates to a method for increasing the degree of etherification of hexamethoxymethylmelamine resin, in particular to a method for increasing the degree of etherification by reducing moisture in an etherification reaction system. Background technique [0002] Hexamethoxymethylmelamine (HMMM) resin is a widely used crosslinking agent, especially used as a coating curing agent and rubber adhesive in large quantities. The production method of hexamethoxymethylmelamine resin usually adopts methanol and hexamethylolmelamine through etherification reaction, and the reaction formula is as follows: [0003] -CH 2 OH+CH 3 OH -→ -CH 2 OCH 3 +H 2 O 【1】 [0004] By the reaction formula, the etherification reaction that takes place between methanol and the methylol group on hexamethylolmelamine is an equilibrium reaction, and in the etherification reaction, the etherification reaction will produce a lot of water, in terms of the amount of hexamet...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C08G12/32C08G12/42C07D251/70
Inventor 陈光炎胡立新郎旭东尤志东
Owner JIANGSU GUOLI CHEM TECH
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