Method for preparing a polymer dispersion

Patent metadata

Field	Value
Publication number	US-12018101-B2
Application number	US-201917309079-A
Country	US
Kind code	B2
Filing date	Jul 25, 2019
Priority date	Jul 25, 2019
Publication date	Jun 25, 2024
Grant date	Jun 25, 2024

Abstract

The present disclosure relates to a process and/or method for producing a polymer dispersion by free-radically initiated emulsion polymerization of radically polymerizable ethylenically unsaturated monomers within a polymerization reactor. The polymer dispersion obtained is transferred to a post-treatment reactor and is post-treated therein. The polymer dispersion within the post-treatment reactor is conveyed, simultaneously to the post-treatment, to a circuit for filtration and analysis and is then subsequently fed back into the post-treatment reactor.

First claim

The invention claimed is:

1. A method for preparing a polymer dispersion, the method comprising the steps of:
providing a polymerization reactor;
obtaining a polymer dispersion by free-radically initiated emulsion polymerization of radically polymerizable ethylenically unsaturated monomers within the polymerization reactor;
transferring the polymer dispersion obtained to a post-treatment reactor; and
post-treating the polymer dispersion within the post-treatment reactor by physical and/or chemical methods and wherein the polymer dispersion in the post-treatment reactor is conveyed simultaneously to the post-treatment and to a circuit for filtration and analysis and then is subsequently fed back into the post-treatment reactor.

2. The method of claim 1 , wherein the polymer dispersion is an aqueous polymer dispersion.

3. The method of claim 1 , wherein the filtration is effected by automatic cleaning filters having mesh sizes of approximately 50 μm to approximately 1000 μm.

4. The method of claim 1 , wherein the analysis comprises determining mean particle size, molar mass, solids content, viscosity, VOC content, residual monomer content, redox potential and/or pH.

5. The method of claim 4 , wherein the analysis is measured using one or more analytical devices.

6. The method of claim 1 , wherein the post-treatment comprises a first phase and a second phase;
wherein in the first phase the polymerized polymer dispersion is depressurized to a pressure from approximately 0.1 bar to approximately 5.0 bar absolute; and
wherein in the second phase a gaseous phase resulting from the depressurization during the first phase is withdrawn.

7. The method of claim 6 , wherein the post-treatment further comprises a third phase and wherein in the third phase a post-polymerization occurs.

8. The method of claim 6 , wherein the post-treatment further comprises a fourth phase and wherein in the fourth phase volatile components are removed by passing over or passing through inert entrainment gases.

9. The method of claim 6 , wherein the post-treatment further comprises allowing the polymer dispersion to be cooled.

10. The method of claim 1 , wherein the filtration and analysis is carried out in single phases of the post-treatment or in every phase of the post-treatment.

11. The method of claim 1 , wherein the circuit is an external circuit.

12. The method of claim 11 , wherein during the post-treatment of the polymer dispersion the polymer dispersion is conveyed continuously from the post-treatment reactor to the external circuit for filtration and analysis and is then subsequently fed back into the post-treatment reactor.

Assignees

• Wacker Chemie Ag

Inventors

• Babar Muhammad
• Eckl Bernhard
• Frauendorfer Eric

Classifications

• C08F6/16

  Purification · CPC title

• C08F2/01

  characterised by special features of the polymerisation apparatus used · CPC title

• C08F6/003

  from polymer solutions, suspensions, dispersions or emulsions without recovery of the polymer therefrom · CPC title

• C08L2205/03

  containing three or more polymers in a blend · CPC title

• C08L2205/025

  containing two or more polymers of the same hierarchy C08L, and differing only in parameters such as density, comonomer content, molecular weight, structure · CPC title