| 摘要 |
Dyed melamine-formaldehyde condensation products are prepared by mixing pigments or dyes with a reaction mixture that contains base compounds for preparing melamine-formaldehyde condensation products. For that purpose (A) a mixture is used that substantially consists of (a) a substituted melamine having the formula (I), in which X1, X2 and X3 are selected from the group that consists of -NH2, -NHR1 and NR1R2, and X1, X2 and X3 are not -NH2 simultaneously, and R1 and R2 are selected from the group that consists of hydroxy-C2-C10-alkyl, hydroxy-C2-C4-alkyl-(oxa-C2-C4-alkyl)n, n being equal to 1 to 5, and amino-C2-C12-alkyl, or mixtures of melamines (I); and optionally (b) formaldehyde or formaldehyde releasing compounds, the molar ratio between formaldehyde and the melamines (I) being selected in a range from 40:1 to 0; (c) a pigment or a dye; and optionally (d) an unsubstituted phenol or phenols substituted with residues selected from the group that consists of C1-C9-alkyl and hydroxy, substituted phenols, C1-C4-alkanes substituted with two or three phenol groups, di(hidroxyphenyl)sulfones or mixtures of such phenols. The amount of pigment or dye ranges from 0.01 to 30 % by weight in relation to (a) and (b), and the amount of phenol ranges from 0 to 5 mol % in relation to (a) and (b). Said mixture is dispersed under intensive stirring until no more pigment agglomerates equal to or larger than 1 .mu.m are present. The mixture produced in (A) is then (B) mixed with melamine and if desired with more phenol, substituted melamine (I) and formaldehyde or formaldehyde releasing compounds, their respective amounts being selected so that the molar ratio between melamines (melamine and (a)) and (b) ranges from 1:1.15 to 1:4.5, the amount of pigment or dye ranges from 0.01 to 5 % by weight in relation to melamine, (a) and (b), and the amount of phenol ranges from 0 to 5 mol % in relation to melamine, (a) and (b). The mixture is then condensed in a known manner.
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