US 5,344,738 A · Process of making toner compositions

Abstract

A process for the preparation of toner compositions with a volume median particle size of from about 1 to about 25 microns, which process comprises: (i) preparing by emulsion polymerization an anionic charged polymeric latex of submicron particle size, and comprised of resin particles and anionic surfactant; (ii) preparing a dispersion in water, which dispersion is comprised of optional pigment, an effective amount of cationic flocculant surfactant, and optionally a charge control agent; (iii) shearing the dispersion (ii) with the polymeric latex thereby causing a flocculation or heterocoagulation of the formed particles of optional pigment, resin and charge control agent to form a high viscosity gel in which solid particles are uniformly dispersed; (iv) stirring the above gel comprised of latex particles, and oppositely charged dispersion particles for an effective period of time to form electrostatically bound relatively stable toner size aggregates with narrow particle size distribution; and (v) heating the electrostatically bound aggregated particles at a temperature above the resin glass transition temperature (Tg) thereby providing the toner composition comprised of resin, optional pigment and optional charge control agent.

Claims37

Dependent claims

A process for the preparation of toner compositions with a volume median particle size of from about 1 to about 25 microns, which process comprises:

(i) preparing by emulsion polymerization an anionic charged polymeric latex of submicron particle size, and comprised of resin particles and anionic surfactant;
(ii) preparing a dispersion in water, which dispersion is comprised of pigment, an effective amount of cationic flocculant surfactant, and optionally a charge control agent;
(iii) shearing the dispersion (ii) with said polymeric latex thereby causing a flocculation or heterocoagulation of pigment, resin and charge control agent to form a high viscosity gel in which particles of pigment, resin and optional charge control agent are uniformly dispersed;
(iv) stirring the above gel for an effective period of time to form electrostatically bound relatively stable toner size aggregates with narrow particle size distribution;
and
(v) heating the electrostatically bound relative stable toner size aggregates at a temperature above the resin glass transition temperature (Tg) thereby providing said toner compositions comprised of resin, pigment and optional charge control agent.

3 more elements

A process for the preparation of a toner, which process comprises:

(i) preparing by emulsion polymerization of styrene, butylacrylate and acrylic acid in the concentration of from about 20 percent to about 50 percent with an ammonium persulfate as an initiator in a concentration of from 0.5 percent to 5 percent and dodecanethiol as a chain transfer agent in the concentration of from about 0.5 percent to 5 percent and in a mixture of 1 to 3 percent solution of nonoionic surfactant and 1 to 3 percent solution of anionic surfactant, an anionic polymeric latex of a submicron particle size of from about 0.1 to about 3 microns of 20 to 50 percent of solids of poly(styrene-butylacrylate-acrylic acid) in a water anionic/nonionic surfactant and with an effective charge mobility or zeta potential of from about -70 to about -120 millivolts;
(ii) preparing by sonication, homogenization or microfluidization a pigment dispersion, which dispersion is comprised of a pigment, a controlled amount of from about 0.01 to about 10 weight percent of cationic surfactant, and an optional charge control agent;
(iii) shearing by a high shear blender or homogenizer at 5,000 to 15,000 rpm the pigment dispersion (ii) with a polymeric latex (i) comprised of resin, a counterionic surfactant with a negative charge of -70 to -120 millivolts, and which is an opposite polarity to that of the pigment dispersion which was prepared with the cationic surfactant, thereby causing a flocculation or heterocoagulation of the formed particles of pigment, resin and charge control agent to form a uniform dispersion of solids comprised of a polymeric latex of poly(styrene-co-butylacrylate-co-acrylic acid), pigment, and optional charge controlling agent;
(iv) stirring at from about 200 to 500 revolutions per minute for from about 1 to about 24 hours the above sheared blend of latex particles and oppositely charged pigment particle, to form electrostatically bound relatively stable, to withstand Coulter Counter measurements, toner size aggregates with a narrow particle size distribution, or GSD of from about 1.16 to about 1.26 as determined on the Coulter Counter;
(v) heating the statically bound aggregated particles at a temperature of from about 5.degree. C. to about 50.degree. C. above the Tg of the resin in the range of from about 50.degree. C. to about 80.degree. C. and preferably in the range of from about 52.degree. C. to about 65.degree. C. to provide a toner comprised of said resin, pigment and optionally a charge control agent;
and optionally
(vi) separating said toner by filtration;
and
(vii) drying said toner.

6 more elements

A process for the preparation of toner with particle sizes of from about 1 to about 25 microns in average volume diameter, which process comprises:

(i) preparing by emulsion polymerization an anionic charged polymeric latex of a submicron particle size, which size is from about 30 nanometers to about 700 nanometers, and with an effective charge mobility or zeta potential of from about -70 to about -120 millivolts, and which latex is comprised of resin and anionic surfactant;
(ii) preparing a pigment dispersion, which dispersion is comprised of pigment, a controlled effective amount of from about 1 to about 10 weight percent of cationic surfactant, and optionally a charge control agent;
(iii) shearing the pigment dispersion (ii) with said polymeric latex (i), thereby causing a flocculation or heterocoagulation of the formed particles of pigment, resin and optional charge control agent to form a uniform dispersion of solids comprised of resin, pigment, and optional charge control agent;
(iv) stirring at from about 200 to about 500 revolutions per minute for from about 1 to about 24 hours the above sheared blend of latex particles and oppositely charged pigment particles to form electrostatically bound relatively stable, as determined by Coulter Counter measurements, toner size aggregates with a narrow particle size distribution, or GSD, of from about 1.16 to about 1.26;
(v) heating the statically bound aggregated particles at a temperature of from about 5.degree. C. to about 50.degree. C. above the Tg of the resin at temperatures of 60.degree. C. to 95.degree. C. to provide a toner composition comprised of resin, pigment and optionally a charge control agent;
and optionally
(vi) separating the toner particles;
and
(vii) drying said toner particles.

6 more elements

Dependencies are inferred from the claim text.

Process of making toner compositions

Life of this patent

Process of making toner compositions

Life of this patent

Abstract

Claims37