Reactive polymer particles and method of preparation
The present invention provides a method for the preparation of a UV curable electrostatographic toner. The process includes the steps of dispersing a polymeric material and a UV curable material and a UV photoinitiator in an organic solvent to form an organic phase. The organic phase is dispersed in an aqueous phase containing a particulate stabilizer to form a dispersion. The dispersion is homogenized and the organic solvent is removed from the dispersed particles in the dispersion which are then recovered.
1. A method for the preparation of a UV curable electrostatographic toner comprising the steps of:
A) dispersing a polymeric material and a UV curable material and a UV photoinitiator in an organic solvent to form an organic phase;
B) dispersing the organic phase in an aqueous phase comprising a particulate stabilizer to form a dispersion and homogenizing the resultant dispersion; and
C) removing the organic solvent from the dispersed particles formed in step (B) and recovering resultant product; wherein no more than a limited amount of heat is used which prevents crosslinking side reactions of the UV curable material.
2. The method of claim 1 wherein the polymeric material comprises at least one of the group consisting of polyurethanes, olefin homopolymers and copolymers, polytrifluoroolefins, polytetrafluoroethylene, polytrifluorochloroethylene, polyamides, acrylic resins, polystyrene, copolymers of styrene, cellulose derivatives, polyesters, polyvinyl resins, and ethylene-vinyl alcohol copolymers.
3. The method of claim 2 wherein the polymeric material further comprises charge control agents, pigments, waxes, or lubricants.
4. The method of claim 2 wherein the polymeric material contains unsaturated groups.
5. The method of claim 1 wherein the UV curable material comprises components containing mono-, di-, or polyfunctional ethylenic unsaturated groups or multi-functional epoxide groups.
6. The method of claim 1 wherein the UV initiator is selected from the group consisting of benzoin, benzoin derivatives, benzil ketals, benzil ketal derivatives, acetophenone, acetophenone derivatives, benzophenone, alkylated or halogenated benzophenone derivatives, anthraquinone, anthraquinone derivatives, thioxanthone, thioxanthone derivatives, and Michler's ketone.
7. The method of claim 1 wherein the particulate stabilizer comprises negatively or positively charged colloidal silica.
8. The method of claim 1 wherein the organic solvent is selected from the group consisting of chloromethane, dichloromethane, ethyl acetate, vinyl chloride, n-propyl acetate, iso-propyl acetate, trichloromethane, carbon tetrachloride, ethylene chloride, trichloroethane, toluene, xylene, cyclohexanone, and 2-nitropropane.
9. The method of claim 1 further comprising washing the resultant product.
10. The method of claim 1 wherein the aqueous phase further comprises
a promoter selected from the group consisting of sulfonated polystyrenes, alginates, carboxyl methylcellulose, tetramethyl ammonium hydroxide, ammonium chloride, diethylaminoethylmethacrylate, water-soluble complex resinous amine condensation products of ethylene oxide, urea, formaldehyde, polyethyleneimine, gelatin, casein, albumin, gluten, and non-ionic materials.
11. The method of claim 10 wherein the promoter is an amount from about 0.2 to about 0.6 parts per 100 parts of aqueous solution by weight.
12. The method of claim 1 wherein the resultant product comprises polymeric particles having a particle size of from 3 to 20 microns.
13. The method of claim 1 wherein the polymeric material comprises a non-reactive polymer binder.
14. The method of claim 13 wherein the polymeric material comprises at least one of the group consisting of polyurethanes, olefin homopolymers and copolymers, polytrifluoroolefins, polytetrafluoroethylene, polytrifluorochloroethylene, polyamides, acrylic resins, polystyrene, copolymers of styrene, cellulose derivatives, polyesters, polyvinyl resins, and ethylene-vinyl alcohol copolymers.