Method for preparing a polymer dispersion

Patent metadata

Field	Value
Publication number	US-2022017656-A1
Application number	US-201917309079-A
Country	US
Kind code	A1
Filing date	Jul 25, 2019
Priority date	Jul 25, 2019
Publication date	Jan 20, 2022
Grant date	—

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

1 . (canceled)

2 . (canceled)

3 . (canceled)

4 . (canceled)

5 . (canceled)

6 . (canceled)

7 . (canceled)

8 . 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 to a circuit for filtration and analysis and then is subsequently fed back into the post-treatment reactor.

9 . The method of claim 8 , wherein the polymer dispersion is an aqueous polymer dispersion.

10 . The method of claim 8 , wherein the circuit is configured such that the flow rate per hour corresponds to at least the liquid volume within the post-treatment reactor.

11 . The method of claim 8 , wherein the filtration is effected by automatic cleaning filters having mesh sizes of approximately 50 μm to approximately 1000 μm.

12 . The method of claim 8 , wherein the analysis comprises determining mean particle size, molar mass, solids content, viscosity, VOC content, residual monomer content, redox potential and/or pH.

13 . The method of claim 12 , wherein the analysis is measured using one or more analytical devices.

14 . The method of claim 8 , 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.

15 . The method of claim 14 , wherein the post-treatment further comprises a third phase and wherein in the third phase a post-polymerization occurs.

16 . The method of claim 14 , 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.

17 . The method of claim 14 , wherein the post-treatment further comprises allowing the polymer dispersion to be cooled.

18 . The method of claim 8 , wherein the filtration and analysis is carried out in single phases of the post-treatment or in every phase of the post-treatment.

19 . The method of claim 8 , wherein the circuit is an external circuit.

20 . The method of claim 19 , 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

• C08F6/006

  Removal of residual monomers by chemical reaction, e.g. scavenging · CPC title

• C08F2/01

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

• C08F18/08

  Vinyl acetate · CPC title

• C08L31/04

  Homopolymers or copolymers of vinyl acetate · CPC title

• C08F218/08

  Vinyl acetate · CPC title