METHOD OF PREPARING TONER HAVING CONTROLLED MORPHOLOGY

• US 20100159385A1
• Filed: 12/23/2008
• Published: 06/24/2010
• Est. Priority Date: 12/23/2008
• Status: Active Grant

• Current Assignee: Eastman Kodak Company
• Original Assignee: Eastman Kodak Company
• Inventors: Yang, Xiqiang
• Granted Patent: US 8,137,888 B2
• Time in Patent Office: Days
• US Class Current: 430/137.100
• CPC Class Codes: C08J 3/16 by coagulating dispersions C08J3/122 takes precedence
• CPC Class Codes: G03G 9/0804 whereby the components are brought together in a liquid dispersing medium
• CPC Class Codes: G03G 9/0827 characterised by their shape, e.g. degree of sphericity
• CPC Class Codes: G03G 9/08755 Polyesters

Abstract

A method for the preparation of shaped polymeric particles, and in a particular embodiment shaped electrostatographic toner particles, of controlled morphology including the following steps. A selected solvent or solvent mixture is used to dissolve a polyester polymer material to form an organic phase, wherein the polyester material is formed from at least one diol and at least one multicarboxylic aromatic acid and has a solubility parameter of greater than 9.0 (cal/cm³)^1/2, the selected solvent or solvent mixture includes at least a first solvent having a solubility parameter of less than 9.0 (cal/cm³)^1/2, and the difference in solubility parameters for the polyester material and the at least first solvent is between 1.0 and 3.0 (cal/cm³)^1/2. The organic phase is dispersed in an aqueous phase containing a particulate stabilizer to form a dispersion, which is then homogenized. The organic solvent is evaporated from the dispersion to form shaped polymeric particles, and the resultant product is recovered, washed and dried.

Claims

1. A method for the preparation of shaped polymeric particles comprising the steps of:

a) combining one or more organic solvents with a polyester material to form an organic phase, wherein the polyester material is formed from at least one diol and at least one multicarboxylic aromatic acid and has a solubility parameter of greater than 9.0 (cal/cm³)^1/2, the at one or more organic solvents includes at least a first solvent having a solubility parameter of less than 9.0 (cal/cm³)^1/2, and the difference in solubility parameters for the polyester material and the at least first solvent is between 1.0 and 3.0 (cal/cm³)^1/2;

b) dispersing the organic phase in an aqueous phase comprising a particulate stabilizer and homogenizing the resultant mixture;

c) evaporating the one or more organic solvents to form shaped polymeric articles; and

d) washing and drying the resultant product.

2. The method of claim 1 wherein an electrostatographic toner charge control agent is added in step a).

3. The method of claim 1 wherein a pigment is added in step a).

4. The method of claim 1 wherein a promoter is added in step b).

5. The method of claim 1 wherein the first solvent is selected from n-propyl acetate, isopropyl acetate, and isobutyl acetate.

6. The method of claim 1 wherein the first solvent is isopropyl acetate.

7. The method of claim 1 wherein the particulate stabilizer is SiO₂.

8. The method of claim 1 wherein the amount of particulate stabilizer is between 1 to 15 parts based on 100 parts of total solids in the polymeric particles.

9. The method of claim 1 wherein the relationship between the aqueous phase and the organic phase, by volume, ranges from 1:

1 to 9;

1.

10. The method of claim 1 wherein shaped particles having a width/length average aspect ratio of less than 0.92 are formed.

11. The method of claim 10, wherein the shaped particles have an average circularity of less than 0.99.

12. The method of claim 1 wherein the polyester material comprises a polyester formed between an alkoxylated bis-phenol A and a dicarboxylic or tricarboxylic aromatic acid.

13. The method of claim 12 wherein the polyester material comprises a polyester formed between an alkoxylated bis-phenol A and one or more of terephthalic acid, phthalic acid, isophthalic acid, trimellitic acid, and trimesic acid.

14. The method of claim 13, wherein the at least first solvent has a solubility parameter of from about 8.0 to about 8.8 (cal/cm³)^1/2.

15. The method of claim 1, wherein the at least first solvent has a solubility parameter of from about 8.0 to about 8.8 (cal/cm³)^1/2.

16. The method of claim 1, wherein the organic phase formed in step a) further comprises a second solvent, wherein the second solvent has a solubility parameter greater than that of the first solvent and a boiling point lower than that of the first solvent.

17. The method of claim 16 wherein the second solvent is selected from dichloromethane, methyl acetate, ethyl acetate, and the first solvent is selected from n-propyl acetate, isopropyl acetate, and isobutyl acetate.

18. The method of claim 16, wherein the first solvent has a solubility parameter of from about 8.0 to about 8.8 (cal/cm³)^1/2, and the second solvent has a solubility parameter equal to or greater than 9.0 (cal/cm³)^1/2.

19. The method of claim 16 wherein the particulate stabilizer is SiO₂.

20. The method of claim 16 wherein the polyester material comprises a polyester formed between an alkoxylated bis-phenol A and a dicarboxylic or tricarboxylic aromatic acid.