Nanosized particles of monoazo laked pigment and non-aqueous compositions containing same

A process for preparing nanoscale particles of monoazo laked pigments, comprising:

• providing an organic pigment precursor to a monoazo laked pigment that contains at least one functional moiety,
• providing a sterically bulky stabilizer compound that contains at least one functional group, and
• carrying out a chemical reaction to form a monoazo laked pigment composition,
• wherein the monoazo laked pigment comprises a mono-azo dye molecule laked with a divalent metal cation,
• whereby the functional moiety found on the pigment precursor is incorporated within the monoazo laked pigment and non-covalently associated with the functional group of the stabilizer, so as to allow the formation of nanoscale-sized pigment particles.

A non-aqueous dispersion composition comprising:

• a non-aqueous carrier,
• a polymeric dispersant, and
• a nanoscale pigment particle composition comprising:
• an organic monoazo laked pigment having at least one functional moiety, and
• a sterically bulky stabilizer compound having at least one functional group,
• wherein the mono-azo laked pigment comprises a mono-azo dye molecule laked with a divalent metal cation;
• the functional moiety associates non-covalently with the functional group;
• and
• presence of the sterically bulky stabilizer limits an extent of particle growth and aggregation, to afford nanoscale-sized pigment particles.