Method of making pigment concentrate particles and product of same

• US 5,629,367 A
• Filed: 01/31/1995
• Issued: 05/13/1997
• Est. Priority Date: 05/26/1992
• Status: Expired due to Fees

• Current Assignee: Eastman Kodak Company
• Original Assignee: Eastman Kodak Company
• Inventors: Bermel, Alexandra D., Lofftus, Kevin D.
• Primary Examiner(s): Seidleck, James J.
• Assistant Examiner(s): Truong, Duc
• Application Number:
  US08/381,385
• Time in Patent Office: 833 Days
• Field of Search: 524/88, 524/366, 524/758, 430/110, 430/111, 430/137, 528/494, 528/934, 523/333, 523/339
• US Class Current: 524/88
• CPC Class Codes: G03G 9/0804 whereby the components are brought together in a liquid dispersing medium
• CPC Class Codes: Y10S 528/934 Latex

Abstract

A method of making pigment concentrate particles having pigment uniformly dispersed in a polymer and exhibiting a controlled morphology and narrow particle size distribution. The method involves dispersing pigment particles in a pigment dispersant liquid to form a first dispersion phase; blending the first dispersion phase with a binder to produce a second dispersion phase; mixing the second dispersion phase under sufficient shear to produce a suspension of small dispersion phase droplets in an immiscible suspending liquid; allowing the small dispersion phase droplets in the suspension to coalesce to a larger size at which substantially no further coalescence can occur; mixing the suspension of coalesced droplets with an extracting liquid to remove the pigment dispersant liquid from the coalesced droplets; and isolating the resulting pigment concentrate particles.

Claims

1. A method of making pigment concentrate particles comprising a pigment uniformly dispersed in a polymer and having a controlled morphology and narrow particle size distribution, comprising the steps of:

dispersing sub-micron sized pigment particles in a pigment dispersant liquid to form a first dispersion phase;

blending said first dispersion phase with a binder to produce a second dispersion phase;

mixing said second dispersion phase under sufficient shear to produce a suspension of small dispersion phase droplets in an immiscible suspending liquid, wherein said suspending liquid and said second dispersion phase are sufficiently immiscible to form two phases and said suspension contains a stabilizer which limits said dispersion phase droplets'"'"' coalescence;

allowing said small dispersion phase droplets in said suspension to coalesce to a larger size at which substantially no further coalescence can occur;

mixing said suspension of coalesced droplets with an amount of an extracting liquid sufficient to remove said pigment dispersant liquid from said coalesced droplets, wherein said extracting liquid is sufficiently miscible with said second dispersion phase to promote diffusion of said pigment dispersant liquid from said coalesced droplets, but immiscible enough with said second dispersion phase as to not disrupt the stability of said coalesced droplets;

whereby said droplets form substantially solidified pigment concentrate particles having a controlled morphology and narrow particle size distribution; and

isolating said pigment concentrate particles.

2. A method according to claim 1, wherein said isolating comprises separating and drying said pigment concentrate particles.

3. A method according to claim 2, wherein said separating is by filtration.

4. A method according to claim 2, wherein said separating is by sedimentation.

5. A method according to claim 2, wherein said separating is by flotation.

6. A method according to claim 5, wherein said flotation comprises a counter-current plug flow process utilizing flotation columns.

7. A method according to claim 1, wherein said pigment dispersant liquid and said binder are selected from the group consisting of ethyl acetate, methylene chloride, methanol, benzyl alcohol, N,N-dimethyl glycerol, ethylene glycol, or a combination thereof, and said suspending liquid is water.

8. A method according to claim 1, wherein said pigment is an organic pigment.

9. A method according to claim 8, wherein said organic pigment is selected from the group consisting of a phthalocyanine, an isoindoline, an indathrone, a triaryl carbonium, an azo pigment lake, a diacrylide yellow, a diazopyrozolione, a laked rhodamine, a perylene, a quinacridone, and an azo metal.

10. A method according to claim 9, wherein said phthalocyanine is selected from the group consisting of a ethyl acetate suspension of a bridged aluminum phthalocyanine, a bromated phthalocyanine, a copper phthalocyanine, an hydroxy aluminum pthalocyanine, a metal-free pthalocyanine, and a milled chlorinated copper pthalocyanine.

11. A method according to claim 9, wherein said triarylcarbonium is selected from the group consisting of a milled ethyl acetate suspension of a sulfonated triphenylmethane, a phosphotungstomolybdic acid laked rhodamine 6G, a phosphomolybdic acid laked rhodamine 6G, a phosphotungstomolybdic acid laked rhodamine B, a phosphotungstomolybdic acid laked rhodamine 3B ethyl ester, a phosphotungstomolybdic acid laked crystal violet, and a phosphomolybdic acid laked crystal violet.

12. A method according to claim 1, wherein said binder is selected from the group consisting of a styrene acrylate, a styrene butadiene, a vinyl toluene butadiene, a polyester, and combinations thereof.

13. A method according to claim 1, wherein said extracting liquid is chosen from the group consisting of a liquid the same as said suspending liquid, a liquid miscible with said suspending liquid that has a mutual miscibility with said pigment dispersant liquid, or a cosolvent which is miscible in both said pigment dispersant liquid and said suspending liquid.

14. A method according to claim 1, wherein the amount of said stabilizer is adjusted to produce an average particle size of from about 3 up to about 60 microns.

15. A method according to claim 1, wherein the amount of said stabilizer is adjusted to produce an average particle size of from between about 20 up to about 40 microns.

16. A method according to claim 1, wherein said second dispersion phase comprises at most 60 weight percent of pigment.

17. A product produced by the method of claim 1.

18. A method according to claim 1, wherein said dispersing comprises milling said pigment in said pigment dispersing liquid.

19. A method according to claim 1, wherein said pigment is an inorganic pigment.

20. A method according to claim 19, wherein said inorganic pigment is selected from the group consisting of titanates, tungstates, arsenates, antimonates, borates, silicates, ferrocyanides, ferricyanides, sulfides, selenides, carbon blacks, chromites, ferrichromites, alumina chlorites, magnetites, aluminates, ferrites, oxides, mixed oxides, hydrated oxides, chromates, and hydrated chromates.

21. A method according to claim 1, wherein said pigment dispersant liquid and said binder are selected from the group consisting of water, methanol, benzyl alcohol, N,N-dimethyl formamide, glycerol, N,N-dimethyl glycerol, ethylene glycol, and combinations thereof, and said suspending liquid is selected from the group consisting of normal, secondary, tertiary, and cyclic alcohols containing at least four carbon atoms, aromatic alcohols, ketones having three or more carbon atoms, halogenated solvents, esters, aliphatic liquids, and combinations thereof.

22. A method according to claim 1, wherein said binder is selected from the group consisting of water, methanol, benzyl alcohol, N,N-dimethyl formamide, glycerol, N,N-dimethyl glycerol, ethylene glycol, and combinations thereof, and said suspending liquid is selected from the group consisting of normal, secondary, tertiary, and cyclic alcohols containing at least four carbon atoms, aromatic alcohols, ketones having three or more carbon atoms, halogenated solvents, esters, aliphatic liquids, and combinations thereof.

23. A method according to claim 1, wherein said binder is chosen from the group consisting of gum arabic, agar, guar gum, polyethylene oxide, polyvinyl alcohol, and polyvinyl carbazole.