Solvent extraction in limited coalescence processes
First Claim
Patent Images
1. A method of making particles having a controlled morphology and narrow particle size distribution, comprising the steps of:
- dispersing a quantity of a material in a dispersant to form a dispersion phase;
blending said dispersion phase with a suspending liquid under high shear to produce a suspension of dispersion phase droplets in said suspending liquid, wherein said suspending liquid and said dispersant are immiscible enough to form two phases and said suspension contains a stabilizer which controls said dispersion phase droplets'"'"' coalescence;
allowing said dispersion phase droplets in said suspension to coalesce to a larger size at which substantially no further coalescence can occur; and
mixing said suspension of coalesced droplets with a sufficient amount of an extracting liquid to remove said dispersant from said coalesced droplets, wherein said extracting liquid is sufficiently miscible with said dispersant and present in sufficient volume to dissolve enough of said dispersant to cause said coalesced droplets to solidify and is selected from the group consisting of a liquid which is the same as said suspending liquid, a liquid miscible with said suspending liquid and exhibiting some mutual miscibility with said dispersant, and a solution of the suspending liquid and a cosolvent, said cosolvent being miscible with both said dispersant and said suspending liquid,whereby said droplets form substantially solidified particles having a controlled morphology and narrow size distribution.
2 Assignments
0 Petitions
Accused Products
Abstract
Powders suitable as electographic toner and/or carrier particles and other powders which utilize a liquid dispersant are produced by limited coalescence techniques. The dispersant is removed by mixing the suspension of coalesced droplets with a sufficient amount of an extracting liquid to cause the dispersant to diffuse out of the coalesced droplets into the extracting liquid.
42 Citations
19 Claims
-
1. A method of making particles having a controlled morphology and narrow particle size distribution, comprising the steps of:
-
dispersing a quantity of a material in a dispersant to form a dispersion phase; blending said dispersion phase with a suspending liquid under high shear to produce a suspension of dispersion phase droplets in said suspending liquid, wherein said suspending liquid and said dispersant are immiscible enough to form two phases and said suspension contains a stabilizer which controls said dispersion phase droplets'"'"' coalescence; allowing said dispersion phase droplets in said suspension to coalesce to a larger size at which substantially no further coalescence can occur; and mixing said suspension of coalesced droplets with a sufficient amount of an extracting liquid to remove said dispersant from said coalesced droplets, wherein said extracting liquid is sufficiently miscible with said dispersant and present in sufficient volume to dissolve enough of said dispersant to cause said coalesced droplets to solidify and is selected from the group consisting of a liquid which is the same as said suspending liquid, a liquid miscible with said suspending liquid and exhibiting some mutual miscibility with said dispersant, and a solution of the suspending liquid and a cosolvent, said cosolvent being miscible with both said dispersant and said suspending liquid, whereby said droplets form substantially solidified particles having a controlled morphology and narrow size distribution. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19)
-
Specification