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During methylolation of melamine with formaldehyde, preferably a complete methylolation of melamine and a lower rate of oligpolymerization of methylolmelamine is promoted to keep the reaction solution at a higher hydrophilicity before dispersion in the oil phase. A dyestuff is added to the water phase to form a colored methylolmelamine water phase. In the next step, an organic solvent and the selected emulsifying agents are added to the colored methylolmelamine (water phase) and stirred with an effective stirrer to provide a w/o emulsion system with the desired particle size. After the w/o emulsion is formed, the pH of the reaction system is adjusted to 5.5-8.0 to increase the polymerization rate and to form hard polymer beads. In an aging step, the polymeric beads are heated to give PMFB with a high degree of crosslinking. The chemical structure of the PMFB is: ##STR2##