Process for producing spherical particles or crystalline polymers

• US 4,254,207 A
• Filed: 12/26/1979
• Issued: 03/03/1981
• Est. Priority Date: 12/26/1979
• Status: Expired due to Term

• Current Assignee: Hercules Incorporated (Ashland Global Holdings, Inc.)
• Original Assignee: Hercules Incorporated (Ashland Global Holdings, Inc.)
• Inventors: Landoll, Leo M., Ropp, Walter S.
• Primary Examiner(s): Ziegler, J.
• Application Number:
  US06/107,471
• Time in Patent Office: 433 Days
• Field of Search: 260/37 R, 260/37 L, 260/37 M, 260/40 R, 260/42.14, 260/42.16, 260/42.22, 525/176, 525/183, 430/109, 430/137
• US Class Current: 430/137.19
• CPC Class Codes: C08J 3/11 from solid polymers
• CPC Class Codes: C08J 3/16 by coagulating dispersions C08J3/122 takes precedence

Abstract

A process for producing uniformly small spherical particles of crystalline, normally solid condensation polymers is described. The process of this invention further provides high yields of hydrophobic, non-agglomerating particles in a useful size range directly, without the need for subsequent processing, and is carried out by forming a dispersion of small liquid particles of the crystalline polymer in certain aprotic liquids containing 0.1 to 20% by weight of the polymer of an acid-modified polymer of propylene in a specified manner, cooling the dispersion with agitation until the liquid particles solidify and recovering the particles.

Claims

1. A process for producing spherical small particles of crystalline, normally solid condensation-type polymers which process comprises agitating under conditions of shear a fluid mixture of said polymer in an aprotic liquid which is a non-solvent for said polymer and which contains dissolved or dispersed therein from 0.1 to 20%, based on the weight of said polymer, of an acid-modified polymer of propylene at a temperature above the crystalline melting point of the condensation-type polymer until a dispersion of small liquid particles is formed, agitating the dispersion while cooling to a temperature below the crystalline melting point of the condensation-type polymer until the liquid particles solidify, and recovering the resulting particles from the aprotic liquid.

2. The process of claim 1 wherein the crystalline condensation-type polymer is a polyester.

3. The process of claim 2 wherein the polyester is an aliphatic polyester.

4. The process of claim 3 wherein the polyester is pigmented.

5. The process of claim 4 in which the pigment is carbon black.

6. The process of claim 4 in which the pigment is magnetic iron oxide.

7. The process of claim 4 wherein the acid modified polymer of propylene is amorphous.

8. The process of claim 7 wherein the carboxyl content of the acid-modified polymer of propylene ranges from 0.15 to 10% by weight of the modified polymer.

9. The process of claim 8 wherein the acid-modified polymer of propylene is maleic anhydride-modified polypropylene.

10. The process of claim 9 wherein the polyester is poly(butylene adipate).

11. The process of claim 8 wherein the acid-modified polymer of propylene is acrylic acid-modified polypropylene.

12. The process of claim 11 wherein the polyester is poly(butylene adipate).