Separation and purification method of polyarylene sulfide

Patent metadata

Field	Value
Publication number	US-11661482-B2
Application number	US-201917273261-A
Country	US
Kind code	B2
Filing date	Oct 18, 2019
Priority date	Oct 19, 2018
Publication date	May 30, 2023
Grant date	May 30, 2023

Abstract

The present disclosure relates to a method of more efficiently separating and purifying a polyarylene sulfide exhibiting excellent strength, heat resistance, flame retardancy, and processability when processed into a molded product after polymerization.

First claim

The invention claimed is:

1. A separation and purification method of a polyarylene sulfide, comprising:
introducing a mixed solution comprising polyarylene sulfide particles, alkali metal halide particles and an organic solvent into a decanter centrifugal separator;
operating the decanter centrifugal separator at a speed of 1000 rpm to 2500 rpm such that the polyarylene sulfide particles are first separated from the mixed solution, and then the alkali metal particles are removed from the mixed solution; and
drying the separated polyarylene sulfide particles at 100° C. to 200° C. before washing with water,
wherein the polyarylene sulfide particles in the mixed solution have a particle size of 100 micrometers to 2000 micrometers, and wherein the alkali metal halide particles in the mixed solution have a particle size of 5 micrometers to 30 micrometers.

2. The separation and purification method of a polyarylene sulfide according to claim 1 , wherein the mixed solution is a waste liquid produced in a synthesizing or washing process of a polyarylene sulfide.

3. The separation and purification method of a polyarylene sulfide according to claim 1 , wherein the polyarylene sulfide particles have a density of 1 g/cm 3 to 1.5 g/cm 3 .

4. The separation and purification method of a polyarylene sulfide according to claim 1 , wherein the alkali metal halide particles are at least one selected from the group consisting of sodium chloride and sodium iodide.

5. The separation and purification method of a polyarylene sulfide according to claim 1 , wherein the alkali metal halide particles have a density of 1.9 g/cm 3 to 3 g/cm 3 .

6. The separation and purification method of a polyarylene sulfide according to claim 1 , wherein the organic solvent is at least one selected from the group consisting of N-methyl-2-pyrrolidone, acetone, and isopropyl alcohol.

7. The separation and purification method of a polyarylene sulfide according to claim 1 , wherein the mixed solution further comprises at least one selected from the group consisting of sodium hydroxide, sodium acetate, sodium sulfide, sodium hydrosulfide, and p-dichlorobenzene.

8. The separation and purification method of a polyarylene sulfide according to claim 1 , wherein the drying step is performed under normal pressure or reduced pressure.

9. The separation and purification method of a polyarylene sulfide according to claim 1 , wherein the polyarylene sulfide particles obtained after the drying have a residual amount of the organic solvent of 0.5 wt % or less.

10. The separation and purification method of a polyarylene sulfide according to claim 1 , further comprising washing the polyarylene sulfide particles obtained after the drying with water, followed by drying at 100° C. to 200° C.

11. A preparation method of a polyarylene sulfide, comprising:
preparing a sulfur source comprising a sulfide of an alkali metal and a mixed solvent of water and an amide-based compound by dehydrating a hydrosulfide of an alkali metal and a hydroxide of an alkali metal in a mixed solvent of water and an amide-based compound;
preparing polyarylene sulfide particles together with alkali metal halide particles by adding a dihalogenated aromatic compound and an amide-based compound to a reactor containing the sulfur source, and performing a polymerization reaction, thus forming a mixed slurry;
washing the mixed slurry comprising the polymerization product containing the polyarylene sulfide particles and the alkali metal halide particles with an organic solvent, thus forming a mixed solution;
introducing the mixed solution into a decanter centrifugal separator;
operating the decanter centrifugal separator at a speed of 1000 rpm to 2500 rpm such that the polyarylene sulfide particles are first separated from the mixed solution, and then the alkali metal particles are removed from the mixed solution; and
drying the separated polyarylene sulfide particles at 100° C. to 200° C., and then washing with water,
wherein the polyarylene sulfide particles in the mixed solution have a particle size of 100 micrometers to 2000 micrometers, and wherein the alkali metal halide particles in the mixed slurry have a particle size of 5 micrometers to 30 micrometers.

Assignees

• Lg Chemical Ltd

Inventors

• Kim Hansol
• Han Joong Jin
• Jo Sanghwan

Classifications

• C08G75/0254

  using metal sulfides · CPC title

• C08G75/0204

  Polyarylenethioethers · CPC title

• C08G75/0281 Primary

  Recovery or purification · CPC title