US 5,294,513 A · Encapsulated electrostatographic toner particles and a process for producing such toners

Abstract

Encapsulated electrostatographic toner particles and a process for making toner particles. The toner particles comprise a pressure fixable core encapsulated in a pressure rupturable shell with the outer surface of the shell being hydrophobic. Preferably, the outer surface of the shell is rendered hydrophobic by having a thermosetting resin precipitated thereon. The process for producing electrostatographic toner particles comprises preparing a core material, encapsulating a discrete portion of the core material in a shell by interfacial polycondensation, and then treating the outer surfaces of the shells with a thermosetting resin to render them hydrophobic. This enables the particles to be formed as a free-flowing, dry powder without requiring costly spray drying.

Claims11

Dependent claims

A process for preparing dry free-flowing encapsulated electrostatographic toner particles without spray drying comprising:

preparing a pressure fixable core material containing a colorant, a binder and at least one oil;
encapsulating discrete portions of the core material in shells by interfacial polymerization of reactive components in an aqueous dispersion to form an aqueous slurry of microcapsules;
adding at least one thermosetting resin to said aqueous slurry of microcapsules;
precipitating said at least one thermosetting resin onto said microcapsule shell outer surfaces to render said microcapsules hydrophobic;
filtering said microcapsules;
and
heating said microcapsules, without spray drying, to a temperature and for a time sufficient to dry said microcapsules.

4 more elements

Dependencies are inferred from the claim text.

Encapsulated electrostatographic toner particles and a process for producing such toners

Life of this patent

Encapsulated electrostatographic toner particles and a process for producing such toners

Life of this patent

Abstract

Claims11