Process for making bimodul, cross-linked toner resin
AssigneeImage Polymers Company
InventorFrancis L. Chupka, Jr.
Life of this patent
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Abstract
A bimodal, crosslinked toner resin can be prepared in non-aqueous solvent, e.g., toluene, using standard solution polymerization techniques. The resin-forming process prepares a precursor resin from ethylenically unsaturated monomer(s), and then grafts maleic anhydride onto the precursor resin to form a modified precursor resin. The modified precursor resin is reacted with a polyfunctional molecule, e.g. a diol, to provide a crosslinked resin. The process is preferably conducted in the presence of a low molecular weight polymeric additive, e.g., polystyrene, to provide a bimodal as well as crosslinked toner resin composition. With the addition of a colorant, a toner powder may be formed.
Claims22
A process for preparing a crosslinked resin comprising the steps of (a) preparing a mixture of maleic anhydride, free-radical initiator, and precursor resin formed by the polymerization of at least one ethylenically unsaturated monomer, (b) heating the mixture of step (a) to a first temperature sufficient to cause maleic anhydride to graft onto said precursor resin and form a modified precursor resin having appended cyclic anhydride groups, (c) adding to said modified precursor resin having appended cyclic anhydride groups a polyfunctional molecule having functional groups reactive with an anhydride group, and (d) heating the mixture of step (c) to a second temperature sufficient to cause covalent bonding between said functional groups and said appended cyclic anhydride groups and thereby form a crosslinked resin.
Dependencies are inferred from the claim text.