Toner aggregation processes
First Claim
1. A process for the preparation of toner compositions comprising:
- (i) preparing a pigment dispersion in water, which dispersion is comprised of a pigment, an ionic surfactant and optionally a charge control agent;
(ii) shearing the pigment dispersion with a latex blend comprised of resin particles, a counterionic surfactant with a charge polarity of opposite sign to that of said ionic surfactant and a nonionic surfactant 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 in the water, and surfactant;
(iii) heating the uniform disperion of solids in water and surfactant of (ii) at a critical temperature region about equal to or above the glass transition temperature (Tg) of the resin, while continuously stirring, to form electrostatically bounded toner size aggregates with a narrow particle size distribution and wherein said critical temperature is from about 0°
C. to about 10°
C. above the resin Tg, and wherein the resin Tg is from about 30°
C. to about 65°
C. and preferably in the range of from about 45°
C. to about 65°
C.;
(iv) heating the electrostatically bounded toner size aggregates from about 10°
C. to about 45°
C. above the Tg of the resin particles to provide a toner composition comprised of polymeric resin, pigment and optionally a charge control agent; and
(v) optionally separating and drying said toner.
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Accused Products
Abstract
A process for the preparation of toner compositions comprising:
(i) preparing a pigment dispersion in water, which dispersion is comprised of a pigment, an ionic surfactant and optionally a charge control agent;
(ii) shearing the pigment dispersion with a latex blend comprised of resin particles, a counterionic surfactant with a charge polarity of opposite sign to that of said ionic surfactant and a nonionic 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 in the water, and surfactant;
(iii) heating the above sheared blend at a critical temperature region about equal to or above the glass transition temperature (Tg) of the resin, while continuously stirring, to form electrostatically bounded toner size aggregates with a narrow particle size distribution and wherein said critical temperature is from about 0° C. to about 10° C. above the resin Tg, and wherein the resin Tg is from about 30° C. to about 65° C. and preferably in the range of from about 45° C. to about 65° C.;
(iv) heating the statically bound aggregated particles from about 10° C. to about 45° C. above the Tg of the resin particles to provide a toner composition comprised of polymeric resin, pigment and optionally a charge control agent; and
(v) optionally separating and drying said toner.
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Citations
21 Claims
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1. A process for the preparation of toner compositions comprising:
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(i) preparing a pigment dispersion in water, which dispersion is comprised of a pigment, an ionic surfactant and optionally a charge control agent; (ii) shearing the pigment dispersion with a latex blend comprised of resin particles, a counterionic surfactant with a charge polarity of opposite sign to that of said ionic surfactant and a nonionic surfactant 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 in the water, and surfactant; (iii) heating the uniform disperion of solids in water and surfactant of (ii) at a critical temperature region about equal to or above the glass transition temperature (Tg) of the resin, while continuously stirring, to form electrostatically bounded toner size aggregates with a narrow particle size distribution and wherein said critical temperature is from about 0°
C. to about 10°
C. above the resin Tg, and wherein the resin Tg is from about 30°
C. to about 65°
C. and preferably in the range of from about 45°
C. to about 65°
C.;(iv) heating the electrostatically bounded toner size aggregates from about 10°
C. to about 45°
C. above the Tg of the resin particles to provide a toner composition comprised of polymeric resin, pigment and optionally a charge control agent; and(v) optionally separating and drying said toner. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 20, 21)
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19. A process for the preparation of toner compositions with controlled particle size comprising:
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(i) preparing a pigment dispersion in water, which dispersion is comprised of a pigment and an ionic surfactant; (ii) shearing the pigment dispersion with a latex blend comprised of resin particles of submicron size, a counterionic surfactant with a charge polarity of opposite sign to that of said ionic surfactant, and which blend contains a nonionic surfactant thereby causing a flocculation or heterocoagulation of the formed particles of pigment; (iii) heating the formed particles of pigment of (ii) in a critical temperature region or above the glass transition temperature (Tg) of the resin particles thereby forming aggregated particles of resin and pigment; (iv) heating the formed aggregated particles of (iii) about above the resin glass transition temperature (Tg) to provide a toner composition comprised of polymeric resin, and pigment; and (v) optionally separating and drying the toner product.
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Specification