Small organic molecules such as sulfanilic acid and 4- aminobenzoic acid are directly attached to the pigment surface by a process involving cyanuric chloride and the corresponding amino acid. The intermediate, a substituted amino-1,3,5-triazine derivatives undergo facile disproportionation when treated with a radical initiator (potassium persulfate) and facilitate the attachment of the organic molecules on the pigment surface. The surface modification achieved by this process is as versatile as the well established diazonium decomposition pathway without the low pH requirement and the potential explosion hazards.This process can be expanded to attach small molecular weight polymers containing an amino end group – examples are poly(ethoxy, propoxy)amines such as Surfonamines. The radical pathway can be exploited to attach other polymers such as poly (styrene-co-maleic anhride) or SMA resins. The ability to attach groups at neutral and basic pH can be exploited to include resin stabilized nano dispersions as the pigment source and skip the milling step usually associated with such a process. This attachment methodology enables customization of pigment surfaces to suit a broad range of applications and ink requirements.
P. K. Sujeeth, Dan Ouellette, Mark Ulrich, John Kane, "Sensient's Suite of Self-Dispersed Color Nano Particle Dispersions - 1,3,5-Triazine Derivatives as Versatile Intermediates for Attachment on Pigments" in Proc. IS&T Int'l Conf. on Digital Printing Technologies and Digital Fabrication (NIP25), 2009, pp 265 - 269, https://doi.org/10.2352/ISSN.2169-4451.2009.25.1.art00074_1