Process for preparing liquid toners with hydrocarbon solvents
AssigneeMinnesota Mining and Manufacturing Company
InventorsPrabhakara S. Rao, Valdis Mikelsons
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Abstract
The toner particles of this invention comprise pigment and a resin. The resin comprises a novel polymer formed from ethylenically unsaturated monomers, macromeric moieties that render the resin dispersible in hydrocarbon solvents, and a surface-release promoting moiety. When used for toner particles the polymer further comprises charge directing chelating moieties. The toner particles also include a charge director, preferably a metal cation. The toner particles, when dispersed in a carrier liquid, are useful as liquid toners for electrographic or electrophotographic processes.
Claims12
A process for preparing a liquid toner comprising the steps of:
- (1) preparing a macromer by (a) combining in a hydrocarbon solvent having a boiling point from 140.degree. to 220 .degree. C. (i) a first free radically polymerizable monomer the polymer of which is soluble in the hydrocarbon solvent, (ii) a chain transfer agent, and (iii) a free radical generating initiator, at least one of which has pendant hydroxy groups, (b) heating the combination, and (c) reacting the pendant hydroxy groups with a coupling agent containing a free radically polymerizable group
- (2) com bining the macromer and hydrocarbon solvent with at least one additional monomer capable of free radical polymerization to form a mixture, wherein a surface release promoting moiety is provided by a method selected from the group consisting of (a) when preparing the macromer providing a fluorine-containing, free-radically polymerizable monomer, (b) when preparing the macromer providing a silicon-containing, free radically polymerizable monomer in an amount not more than 10% by weight of the macromer, (c) when combining the macromer and hydrocarbon with at least one additional monomer, providing a fluorine-containing, free-radically polymerizable monomer, and (d) when combining the macromer and hydrocarbon with at least one additional monomer, providing a fluorine-containing, free-radically polymerizable monomer,
- (3) free radically polymerizing the polymerizable components of the mixture formed in step (2) in the presence of a metal cation, and
- (4) dispersing a pigment in the mixture of step (3).
Dependencies are inferred from the claim text.