Toner composition with semi-crystalline polyester wax and method of preparation
First Claim
1. A method for the preparation of electrostatographic toner comprising the steps of:
- (a) dissolving at ambient temperature a low melting point hydrophobic semi-crystalline polyester wax in a first solvent capable of dissolving the wax at ambient temperature, thereby forming a solution;
(b) forming a pigment dispersion at ambient temperature by mixing a pigment, a first polymer material and a second solvent in which the hydrophobic wax is insoluble at ambient temperature;
(c) admixing the wax solution with the pigment dispersion so resulting in precipitation of the wax upon the surface of the pigment;
(d) mixing the wax coated pigment dispersion thus formed with a solvent in which the hydrophobic wax is insoluble at ambient temperature, and optionally, a second polymer material and, optionally, a charge-control agent to form an organic phase;
(e) dispersing the organic phase in an aqueous phase comprising a particulate stabilizer and, optionally, a promoter and homogenizing the resultant mixture; and
(f) evaporating the solvent and washing and drying the resultant product.
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Abstract
A method is described for the preparation of electrostatographic toner particles which involves the surface treatment of a pigment by depositing thereon a coating of a low melting point hydrophobic semi-crystalline polyester wax. The method involves preparing a wax solution by dissolving at ambient temperature a low melting point hydrophobic semi-crystalline polyester wax in a first solvent capable of dissolving the wax at ambient temperature; forming a pigment dispersion by mixing at ambient temperature a pigment, a first polymer material and a second solvent in which the hydrophobic wax is insoluble at ambient temperature; admixing the wax solution with the pigment dispersion so resulting in precipitation of the wax upon the surface of the pigment; mixing the wax coated pigment dispersion thus formed with a solvent in which the hydrophobic wax is insoluble at ambient temperature and, optionally, a second polymer material and, optionally, a charge-control agent to form an organic phase; dispersing the organic phase in an aqueous phase comprising a particulate stabilizer and, optionally, a promoter; homogenizing the resultant mixture, and evaporating the solvent and washing and drying the resultant product.
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Citations
19 Claims
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1. A method for the preparation of electrostatographic toner comprising the steps of:
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(a) dissolving at ambient temperature a low melting point hydrophobic semi-crystalline polyester wax in a first solvent capable of dissolving the wax at ambient temperature, thereby forming a solution; (b) forming a pigment dispersion at ambient temperature by mixing a pigment, a first polymer material and a second solvent in which the hydrophobic wax is insoluble at ambient temperature; (c) admixing the wax solution with the pigment dispersion so resulting in precipitation of the wax upon the surface of the pigment; (d) mixing the wax coated pigment dispersion thus formed with a solvent in which the hydrophobic wax is insoluble at ambient temperature, and optionally, a second polymer material and, optionally, a charge-control agent to form an organic phase; (e) dispersing the organic phase in an aqueous phase comprising a particulate stabilizer and, optionally, a promoter and homogenizing the resultant mixture; and (f) evaporating the solvent and washing and drying the resultant product. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 18)
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10. In a method of preparing electrostatographic toner by dispersing an organic phase in an aqueous phase to yield a layer of particulate suspension stabilizer on the surface of a polymer, the improvement which comprises forming a wax coated pigment dispersion by dissolving a low melting point hydrophobic semi-crystalline hydrophobic wax in a first solvent capable of dissolving the wax at ambient temperature thereby forming a wax solution;
- forming a pigment dispersion by mixing at ambient temperature a pigment, a first polymer material and a second solvent in which the hydrophobic wax is insoluble at ambient temperature;
admixing the wax solution with the pigment dispersion so resulting in the wax precipitating out upon the surface of the pigment;
mixing the wax coated pigment dispersion thus formed with a solvent in which the hydrophobic wax is insoluble at ambient temperature and, optionally, a second polymer material and, optionally, a charge-control agent to form the organic phase for dispersing in the aqueous phase. - View Dependent Claims (11, 12, 13, 14, 15, 19)
- forming a pigment dispersion by mixing at ambient temperature a pigment, a first polymer material and a second solvent in which the hydrophobic wax is insoluble at ambient temperature;
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16. A method of preparing a uniform coating of a low melting point hydrophobic semi-crystalline polyester wax on pigment particles comprising the steps of:
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(a) forming a solution of the low melting point hydrophobic wax in a first solvent capable of dissolving the wax at ambient temperature; (b) mixing the wax solution with a pigment particle dispersion in a dispersing liquid at ambient temperature to deposit the wax on the pigment particles as a coating on the surface of the particles; and (c) recovering the coated pigment particles. - View Dependent Claims (17)
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Specification