Organic pigment dyestuffs and process for their production

摘要

Organic pigment dyestuffs are obtained by a process wherein a water-soluble organic dyestuff containing hydrogen atoms capable of reacting with formaldehyde, is reacted with formaldehyde, a formaldehyde-yielding agent and/or with a soluble or dispersible phenoor aminoplast condensate or an etherification product thereof, said pheno- or aminoplast condensate containing free methylol groups, in the presence of an amount of water or of an aqueous-organic solvent which is at least ten times the weight of the dyestuff, referred to the amount by weight of the dyestuff used, at a pH value below 7, until the reaction product is precipitated and completely condensed. The reaction may be carried out at elevated temperature. In examples various dyestuffs are condensed with a condensation product of melamine, formaldehyde, methanol and ethylene glycol, with a phenol/formaldehyde condensation product, with formaldehyde and a condensation product of melamine, formaldehyde and diethanolamine, with formaldehyde and a condensation product of dicyano-diamide and formaldehyde, with a condensation product of melamine, formaldehyde and N-diethanol-melamine, and with tetramethylol-acetylene diurea. Other materials are mentioned.