| 摘要 |
PURPOSE:To obtain a melamine resin easily soluble in water and capable of forming a cured product excellent in water and heat resistance, by reacting melamine with formaldehyde and methyl alcohol and specifying each of the degree of methoxylation and the pH in the reaction in a specified range. CONSTITUTION:A mixture is formed by mixing 1mol of melamine with 1.8- 2.8mol of formaldehyde and 0.1-2mol of methyl alcohol. This mixture is subjected, in one stage, to both methylolation and methoxylation reactions at a pH in the range of 3-6.5 in the presence of an acidic catalyst such as an organic acid such as p-toluenesulfonic acid or an inorganic acid. The degree of methoxylation is increased finally to 2-10%, and the pH is adjusted to 7.8-8.5 by adding an acid or a base, if necessary, to form a melamine resin.
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