Thermosetting dyed latex colorant dispersions

Claim 1

In a process for producing a thermosetting colorant comprising a stable aqueous suspension of nanoparticles of crosslinked thermosetting polymer, wherein water-insoluble dye molecules are intermixed in a polymer matrix, according to a process comprising the steps of: A. Mixing together an organic solvent, a polymer comprising an epoxy resin that is soluble in said solvent but substantially insoluble in water and dye which is soluble in said solvent and substantially insoluble in water to form a homogeneous mixture, wherein said solvent is characterized by a vapor pressure higher than water and said mixing is continued until said dye and polymer are molecularly intermixed to form a dyed polymer that substantially is dissolved within said solvent; and B. Dispersing by adding said solvent/polymer/dye solution to water, in a concentration range of 1.0 percent to 50.0 percent, by weight, and agitating until an emulsion results wherein droplets of solvent/polymer/dye less than 10 microns in diameter comprise a discontinuous phase in water as the continuous phase, wherein said dispersing step is done under conditions where interfacial tension between the organic solvent and the water is less than approximately 20 dynes/cm; and C. Removing substantially all of said solvent to define a resulting fluid comprising an aqueous suspension of dyed polymer nanoparticles; the improvement which comprises the step of combining dyed polymer with a curing agent by contacting curing agent in a liquid phase with polymer, before or after said dispersing step, to create a final fluid adapted to be cross-linked selectively upon applying heat to raise the temperature of the dyed polymer and curing agent combination above its glass transition temperature.