Toner composition with elastomeric thermoplastic polymer and process of preparing
First Claim
1. A method for the preparation of electrostatographic toner comprising the steps of:
- (a) dissolving at ambient temperature an elastomeric thermoplastic polymer selected from the group consisting linear styrene-isoprene-styrene triblock copolymers, linear styrene-ethylene-butylene-styrene triblock copolymers, linear styrene-isoprene diblock copolymers and linear styrene-ethylene-propylene diblock copolymers in a first solvent capable of dissolving the polymer at ambient temperature, thereby forming a polymer solution;
(b) forming a pigment dispersion at ambient temperature by mixing a pigment, a first polymer material and a second solvent in which the elastomeric thermoplastic polymer is insoluble at ambient temperature;
(c) admixing the resultant polymer solution at ambient temperature with the pigment dispersion so resulting in the precipitation of the elastomeric thermoplastic polymer upon the surface of the pigment;
(d) mixing the polymer coated pigment dispersion thus formed at ambient temperature with a solvent in which the elastomeric thermoplastic polymer 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 an elastomeric thermoplastic polymer. The method involves preparing a polymer solution by dissolving an elastomeric thermoplastic polymer selected from the group consisting of linear styrene-isoprene-styrene triblock copolymers, linear styrene-ethylene-butylene-styrene triblock copolymers, linear styrene-isoprene diblock copolymers and linear styrene-ethylene-propylene diblock copolymers in a first solvent capable of dissolving the polymer 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 elastomeric thermoplastic polymer is insoluble at ambient temperature; admixing the polymer solution with the pigment dispersion so resulting in the elastomeric thermoplastic polymer precipitating out upon the surface of the pigment; mixing the elastomeric thermoplastic polymer coated pigment dispersion thus formed with a solvent in which the elastomeric thermoplastic polymer 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
18 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 an elastomeric thermoplastic polymer selected from the group consisting linear styrene-isoprene-styrene triblock copolymers, linear styrene-ethylene-butylene-styrene triblock copolymers, linear styrene-isoprene diblock copolymers and linear styrene-ethylene-propylene diblock copolymers in a first solvent capable of dissolving the polymer at ambient temperature, thereby forming a polymer solution; (b) forming a pigment dispersion at ambient temperature by mixing a pigment, a first polymer material and a second solvent in which the elastomeric thermoplastic polymer is insoluble at ambient temperature; (c) admixing the resultant polymer solution at ambient temperature with the pigment dispersion so resulting in the precipitation of the elastomeric thermoplastic polymer upon the surface of the pigment; (d) mixing the polymer coated pigment dispersion thus formed at ambient temperature with a solvent in which the elastomeric thermoplastic polymer 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, 17)
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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 an elastomeric thermoplastic polymer coated pigment dispersion by dissolving an elastomeric thermoplastic polymer selected from the group consisting of linear styrene-isoprene-styrene triblock copolymers, linear styrene-ethylene-butylene-styrene triblock copolymers, linear styrene-isoprene diblock copolymers and linear styrene-ethylene-propylene diblock copolymers in a first solvent capable of dissolving the elastomeric thermoplastic polymer at ambient temperature thereby forming a polymer solution;
- forming a pigment dispersion by mixing at ambient temperature a pigment, a first polymer material and a second solvent in which the elastomeric thermoplastic polymer is insoluble at ambient temperature;
admixing the polymer solution with the pigment dispersion so resulting in the elastomeric thermoplastic polymer precipitating out upon the surface of the pigment;
mixing the elastomeric thermoplastic polymer coated pigment dispersion thus formed with a solvent in which the elastomeric thermoplastic polymer 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, 18)
- forming a pigment dispersion by mixing at ambient temperature a pigment, a first polymer material and a second solvent in which the elastomeric thermoplastic polymer is insoluble at ambient temperature;
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15. A method of preparing a uniform coating of an elastomeric thermoplastic polymer selected from the group consisting of linear styrene-isoprene-styrene triblock copolymers, linear styrene-ethylene-butylene-styrene triblock copolymers, linear styrene-isoprene diblock copolymers and linear styrene-ethylene-propylene diblock copolymers on pigment particles comprising the steps of:
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(a) forming a solution of the elastomeric thermoplastic polymer in a first solvent capable of dissolving the polymer at ambient temperature; (b) mixing the polymer solution with a pigment particle dispersion in a dispersing liquid at ambient temperature to deposit the polymer on the pigment particles as a coating on the surface of the particles; and (c) recovering the coated pigment particles. - View Dependent Claims (16)
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Specification