METHOD AND PREPARATION OF CHEMICALLY PREPARED TONERS
First Claim
1. A method of making polymeric particles having a controlled size and size distribution which comprises:
- dissolving a polymer material in an organic solvent to form an organic phase, said solvent being immiscible with water;
forming a dispersion of small droplets of said organic phase in an aqueous phase containing a particulate stabilizer by high shear agitation;
evaporating the organic solvent to obtain polymeric particles with particulate stabilizer on the surface thereof; and
treating the obtained polymeric particles with a basic silicate salt solution at a pH of from 11 to 13 to remove particulate stabilizer from the precipitated polymer particles.
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Abstract
A method of making polymeric particles having a controlled size and size distribution, and in particular a method for the preparation of chemically prepared toners, via evaporative limited coalescence process, wherein basic silicate salts are employed to remove particulate stabilizer from precipitated polymer particles. The process includes the steps of dispersing polymeric binder materials and optional additives in an organic solvent to form an organic phase. The organic phase is dispersed by high shear agitation in an aqueous phase containing a particulate stabilizer, e.g. colloidal silica, to form a dispersion of small droplets of the organic phase in the aqueous phase. The dispersion is homogenized and the organic solvent is removed from the dispersed particles in the dispersion by evaporation, and polymeric particles are precipitated with particulate stabilizer on the surface thereof, which are then recovered, treated with a basic silicate salt to remove particulate stabilizer, and washed and dried.
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Citations
19 Claims
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1. A method of making polymeric particles having a controlled size and size distribution which comprises:
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dissolving a polymer material in an organic solvent to form an organic phase, said solvent being immiscible with water; forming a dispersion of small droplets of said organic phase in an aqueous phase containing a particulate stabilizer by high shear agitation; evaporating the organic solvent to obtain polymeric particles with particulate stabilizer on the surface thereof; and treating the obtained polymeric particles with a basic silicate salt solution at a pH of from 11 to 13 to remove particulate stabilizer from the precipitated polymer particles. - View Dependent Claims (2, 3, 4, 5, 6, 7, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19)
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8. (canceled)
Specification