Processes for preparing crosslinked resins and toner compositions therefrom

A reactive melt mixing process for preparing a low fix temperature toner resin, comprising:

• preblending a reactive base resin, a high temperature half life free radical initiator compound and optionally an unreactive resin or wax as a free radical initiator diluent;
• feeding the mixture to an extruder;
• heating the mixture at a temperature of from about 70.degree. C. to about 120.degree. C. to melt the base resin and to further disperse the free radical initiator therein but without significant free radical initiator degradation or;
• simultaneously adding to the melt mixture a vinyl monomer for forming crosslinked segments comprised of said vinyl monomers between adjacent reactive resin molecules;
• heating to a higher temperature of from about 130.degree. C. to about 200.degree. C. to cause free radical initiator degradation;
• retaining the polymer melt in the extruder for a sufficient residence time of from about 10 seconds to about 10 minutes to complete the crosslinking;
• providing sufficiently high shear during the vinyl monomer interchain crosslinking reaction thereby keeping the gel particles formed during crosslinking small in size and well distributed in the polymer melt;
• optionally devolatilizing the melt to remove any effluent volatiles;
• and pumping the crosslinked resin melt through a die to a pelletizer.