| 摘要 |
PROBLEM TO BE SOLVED: To provide a low formaldehyde amino resin that has a low formaldehyde content with high safety in the construction works and dwelling environments and shows excellent storage stability and the excellent adhesion resistant to water and to boiling water. SOLUTION: The total of melamine and urea is 100 wt.% where the proportion of melamine is 50-98 wt.%, while the urea is 2-50 wt.% and formaldehyde is used in an amount of 1.5-3.0 moles per mole of the melamine. In the initial reaction, the methylolation is carried out with only melamine and formaldehyde at a pH of 7.5-11.0, subsequently 0.1-2.0 moles of methanol per mole of formaldehyde is used to effect condensation and etherification reactions in a strong alkalinity of >=12.0 pH and finally urea is added for the following reactions.
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