US 6,190,820 B1 · Toner processes

Abstract

A process for the preparation of toner by, for example (i) generating by emulsion polymerization in the presence of an initiator a first resin latex emulsion; (ii) generating in the presence of an oil soluble initiator by solution polymerization a second resin latex; (iii) mixing (ii) with a colorant; (iiib) mixing the resin latex emulsion of (i) with the resin/colorant mixture of (iii) to provide a blend of a resin and colorant; (iv) adding an aqueous inorganic cationic coagulant solution of a metal salt and optionally an organic cationic coagulant to the resin/colorant blend of (iiib); (v) heating at a temperature of from about 5° C. to about 10° C. below the resin Tg of (i), to form aggregate particles; (vi) adjusting the pH of (v) by the addition of a base; (vii) heating the aggregate particles of (v) at temperatures of from about 5° C. to about 50° C. above the Tg of the resin of (i), followed by the addition of an acid.

Claims31

Dependent claims

A process for the preparation of toner comprising

(i) generating by emulsion polymerization in the presence of an initiator a first resin latex emulsion;
(ii) generating by solution polymerization in the presence of an oil soluble initiator a second resin latex;
(iii) mixing (ii) with a colorant thereby providing a colorant dispersion;
(iiib) mixing the resin latex emulsion of (i) with the resin/colorant mixture of (iii) to provide a blend of resin and colorant;
(iv) adding an inorganic cationic coagulant solution of a metal salt, an organic cationic coagulant solution or mixtures thereof to the resin/colorant blend of (iiib);
(v) heating at a temperature of from about 5° C. to about 10° C. below the latex resin Tg of (i) to form aggregate particles, and which particles are at a pH of from about 2 to about 4;
(vi) adjusting the pH of (v) to about 6.5 to about 9 by the addition of a base;
(vii) heating the aggregate particles at a temperature of from about 5° C. to about 50° C. above the Tg of the latex resin of (i), followed by a reduction of the pH to from about 2.5 to about 5 by the addition of an acid thereby resulting in coalesced toner;
and
(viii) optionally isolating the toner.

7 more elements

A process for the preparation of a toner comprising

(i) generating by emulsion polymerization in the presence of an initiator a latex emulsion containing a first resin;
(ii) generating by solution polymerization a second resin, and optionally wherein the resulting resin is dispersed in warm water to provide a dispersion of the second resin;
(iii) mixing (ii) and a colorant wherein there is formed a coating of resin (ii) on said colorant thereby providing a stable colorant dispersion, and wherein optionally from about 70 to about 95 percent of colorant is coated by said resin;
(iv) blending the resin latex emulsion of (i) with the colorant/resin dispersion (iii) to form a resin latex/colorant blend;
(v) adding an aqueous inorganic cationic coagulant solution of a metal salt, an organic cationic coagulant or mixtures thereof to the resin latex/colorant blend (iv), while optionally continuously subjecting the blend to high shear to optionally induce the formation of a homogeneous gel of the resin/colorant blend;
(vi) heating the sheared gel of (v) at a temperature of from about 5° C. to about 10° C. below the latex resin (i) glass transition temperature optionally while continuously stirring to form aggregate particles of resin, coagulant and colorant;
(vii) optionally retaining (vi) for an optional period of from about 1 to about 3 hours to primarily minimize growth of the aggregates and optionally achieving a narrow GSD of from about 1.15 to about 1.24;
(viii) optionally adding a further latex comprised of resin (i), wherein the addition of said latex enables the formation of a coating on said aggregates of (vii);
(ix) changing the pH of said aggregates of (vii) which is initially in the range of from about 2 to about 3.5 to a pH in the range of about 6.5 to about 9 by the addition of a base to thereby primarily stabilize the aggregate particles from further growth;
(x) heating the aggregate particles of (ix) at temperatures of from about 5° C. to about 50° C. above the Tg of the resin (i), followed by a reduction of the pH from the range of about 6.5 to about 9.0 to a pH range of about 2.5 to about 5 with an acid to form coalesced particles of a toner composition of resin (i), resin (ii), resin (viii) and colorant;
and
(xi) optionally separating and drying the toner.

9 more elements

Dependencies are inferred from the claim text.

Toner processes

Life of this patent

Toner processes

Life of this patent

Abstract

Claims31