Colloidally stabilized suspension process

• US 5,133,992 A
• Filed: 05/07/1990
• Issued: 07/28/1992
• Est. Priority Date: 03/21/1988
• Status: Expired due to Term

• Current Assignee: Eastman Kodak Company
• Original Assignee: Eastman Kodak Company
• Inventors: Nair, Mridula, DiPrima, Donna A., Pierce, Zona R.
• Primary Examiner(s): Lovering, Richard D.
• Application Number:
  US07/520,329
• Time in Patent Office: 813 Days
• Field of Search: 252/356, 264/4.3, 264/4.7, 427/213.34, 525/902, 526/909, 526/910, 526/911
• US Class Current: 427/213.34
• CPC Class Codes: G03G 9/0825 characterised by their structure; characterised by non-homogenuous distribution of components microcapsular toners G03G9/093
• CPC Class Codes: G03G 9/08795 characterised by their chemical properties, e.g. acidity, molecular weight, sensitivity to reactants
• CPC Class Codes: Y10S 516/06 Protein or carboxylic compound containing
• CPC Class Codes: Y10S 525/902 Core-shell
• CPC Class Codes: Y10S 526/909 Polymerization characterized by particle size of product
• CPC Class Codes: Y10S 526/91 Suspending agents
• CPC Class Codes: Y10S 526/911 Emulsifying agents
• CPC Class Codes: Y10T 428/2998 including synthetic resin or polymer

Abstract

A method of preparing polymer particles having narrow size distribution in a suspension process employing a solid colloidal stabilizing agent. The solid colloidal stabilizer is a copolymer of about 25 to about 80% by weight, based on total monomer weight, of an addition polymerizable nonionic oleophilic monomer, about 5 to about 45%, by weight, of an addition polymerizable nonionic hydrophilic monomer, about 1 to about 50% of an addition polymerizable ionic monomer, and 0 to about 20 percent, by weight, of a crosslinking monomer having at least two addition polymerizable groups. Also disclosed are polymeric particles comprising a core polymer covered by a layer of the smaller copolymer stabilizer particles and electrostatographic toners comprising such polymeric particles.

Claims

1. In a method of preparing polymer particles which comprises forming a suspension of polymer droplets in an aqueous medium and forming a layer of solid colloidal stabilizer on the surface of the droplets to control the size and size distribution of the polymer particles, the improvement wherein the stabilizer comprises a copolymer of

(1) about 25 to about 80 percent by weight, based on total monomer weight, of an addition polymerizable nonionic oleophilic monomer;

(2) about 5 to about 45 percent by weight, based on total monomer weight, of an addition polymerizable nonionic hydrophilic monomer;

(3) about 1 to about 50 percent by weight, based on total monomer weight, of an addition polymerizable ionic monomer; and

(4) 0 to about 20 percent by weight based on total monomer weight, of a crosslinking monomer having at least two addition polymerizable groups.

2. The method of claim 1, wherein said copolymer comprises (1) about 35 to about 65 percent by weight of the nonionic oleophilic monomer, about 10 to about 35 percent by weight of the nonionic hydrophilic monomer, about 10 to about 25 percent by weight of the ionic monomer and about 4 to about 15 percent by weight of the crosslinking monomer.

3. The method of claim 1, wherein the ionic monomer is anionic.

4. The method of claim 1, wherein the ionic monomer is cationic.

5. The method of claim 1, wherein the nonionic oleophilic monomer is styrene.

6. The method of claim 5, wherein the nonionic hydrophilic monomer is 2-hydroxyethyl methacrylate, the ionic monomer is methacrylic acid and the crosslinking monomer is ethylene dimethacrylate.

7. The method according to claim 1, wherein the copolymer has an average diameter in the range of about 0.01 to about 1 micrometer.

8. The method of claim 7, wherein the copolymer has an average diameter in the range of about 0.01 to about 0.15 micrometer.

9. The method of claim 1 comprising the additional step of forming the polymer droplets by suspending polymerizable liquid monomer in aqueous medium and polymerizing said monomer.

10. The method of claim 1 comprising the additional step of forming the polymer droplets by dissolving a polymer in a solvent that is immiscible with the aqueous media.