# US 10,501,582 B2 · Method of producing polyarylene sulfide

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- Number: US 10,501,582 B2
- Document ID: US10501582B2
- Status: Granted
- Kind: B2
- Application number: 15/759,540
- Filed: 2016-09-30
- Published: 2019-05-23
- Granted: 2019-12-10
- Earliest claimed: 2015-09-30
- Assignees: Kureha Corporation
- Applicants: Kureha Corporation
- Inventors: Akihiro Konno; Ken-Ichi Takaki; Hiroyuki Sato
- Web page: https://patentgrep.com/patent/US10501582B2

## CPC

- C08G 75/0263: using elemental sulfur
- C08G 75/0209: derived from monomers containing one aromatic ring
- C08G 75/025: Preparatory processes
- C08G: MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS

## Abstract

The present invention is to provide a method of producing polyarylene sulfide that can produce polyarylene sulfide having a low halogen content simply and easily and at low cost. The method of producing polyarylene sulfide according to an embodiment of the present invention includes: a preparation step of preparing a mixture containing an organic amide solvent, a sulfur source, a dihalo aromatic compound, and an alkali metal hydroxide; a first-stage polymerization step of producing a prepolymer until a pH of a reaction system reaches a range of lower than 10 but 7 or higher by initiating a polymerization reaction by heating the mixture; and a second-stage polymerization step of continuing the polymerization reaction.

## Claims

### Claim 1

A method of producing polyarylene sulfide that polymerizes a sulfur source and a dihalo aromatic compound in an organic amide solvent, the method comprising:
a preparation step of preparing a mixture containing an organic amide solvent, a sulfur source,
a dihalo aromatic compound, and an alkali metal hydroxide;
a first-stage polymerization step of producing a prepolymer until a pH of a reaction system reaches a range of lower than 10 but 7 or higher by initiating a polymerization reaction by heating the mixture; and
a second-stage polymerization step of continuing the polymerization reaction,
wherein in the preparation step, the mixture containing from 0.7 to 0.9 mol of the alkali metal hydroxide per 1 mol of the sulfur source is prepared.

### Claim 2 (depends on 1)

The method according to claim 1, wherein
in the preparation step, a mixture containing the alkali metal hydroxide in an amount that is less than an equimolar amount per 1 mol of the sulfur source is prepared; and
in the second-stage polymerization step, the polymerization reaction is continued by adding from 0.01 to 0.6 mol of alkali metal hydroxide per 1 mol of the sulfur source.

### Claim 3 (depends on 1)

The method according to claim 1, wherein in the first-stage polymerization step, the prepolymer is produced until a conversion ratio of the dihalo aromatic compound reaches 50% or greater.

### Claim 4 (depends on 1)

The method according to claim 1, wherein the polymerization reaction is performed by heating the mixture prepared in the preparation step at a temperature of 170 to 270° C. in the first-stage polymerization step, and then the polymerization reaction is continued while heating at a temperature of 245 to 290° C. in the second-stage polymerization step.

### Claim 5 (depends on 1)

The method according to claim 1, wherein, in the second-stage polymerization step, the polymerization reaction is continued in a condition where the reaction system is phase-separated into a concentrated polymer phase and a dilute polymer phase in the presence of a phase separation agent.

### Claim 6 (depends on 1)

The method according to claim 1, wherein, in the first-stage polymerization step and the second-stage polymerization step, the polymerization reaction is performed in a homogeneous liquid phase condition.

### Claim 7 (depends on 1)

The method according to claim 1, wherein, in the first-stage polymerization step and/or the second-stage polymerization step, the polymerization reaction is performed in the presence of an end-capping agent.