Method of manufacturing polyarylene sulfide, and polyarylene sulfide

Abstract

To provide a method of manufacturing polyarylene sulfide (PAS) while efficiently recovering an organic amide solvent at a low energy cost, without using an organic solvent, from washing wastewater produced by washing a raw material mixture containing PAS and an organic amide solvent using a solvent containing water; a method of manufacturing PAS by reducing the amount of water supplied when washing the raw material mixture using a solvent containing water; and PAS manufactured by these methods. A method according to the present invention includes: a step of mixing a solvent containing water and a raw material mixture that contains PAS and an organic amide solvent, and then washing the PAS; a step of obtaining a separated liquid by solid-liquid separation; and a step of separating the separated liquid into distilled vapor having a smaller amount of the organic amide solvent and a recovered liquid having a larger amount of the organic amide solvent by heating, where the heating is performed utilizing an increase in temperature based on compressing the distilled vapor and/or compressing a heat medium heat-exchanged with the distilled vapor.

1 . A method of manufacturing polyarylene sulfide, comprising:
 (a) a washing step of mixing a solvent containing water with a raw material mixture that contains polyarylene sulfide and an organic amide solvent to obtain a dispersion, dissolving the organic amide solvent in the solvent containing water, and then washing the polyarylene sulfide;   (b) a separating step of solid-liquid separating the dispersion in the washing step to obtain a separated liquid; and   (c) a distilling step of separating the separated liquid into distilled vapor containing a solvent containing water having a smaller amount of the organic amide solvent, and recovered liquid containing a solvent containing water having a larger amount of the organic amide solvent by heating the separated liquid obtained in the separating step; wherein   heating in the distilling step is performed utilizing an increase in temperature based on compressing the distilled vapor and/or an increase in temperature based on compressing a heat medium heat-exchanged with the distilled vapor.   
     
     
         2 . The method according to  claim 1 , further comprising:
 (d) an organic amide solvent concentrating step of distilling the recovered liquid to obtain a concentrated liquid containing a solvent with a higher amount of the organic amide solvent.   
     
     
         3 . The method according to  claim 1 , wherein the raw material mixture is obtained through:
 a preliminary washing step of mixing polyarylene sulfide or mixture containing polyarylene sulfide with a washing liquid containing an organic amide solvent to obtain a dispersion, and then washing the polyarylene sulfide; and   a preliminary separating step of solid-liquid separating the dispersion in the preliminary washing step, and then separating into a separated liquid and mixture containing polyarylene sulfide.   
     
     
         4 . The method according to  claim 3 , wherein at least one portion of the recovered liquid and/or at least one portion of the concentrated liquid is used as the washing liquid in the preliminary washing step. 
     
     
         5 . The method according to  claim 3 , wherein in the organic amide solvent concentrating step, distillation of the recovered liquid is performed by distilling a mixture of the recovered liquid and separated liquid separated in the preliminary separating step. 
     
     
         6 . The method according to  claim 5 , wherein at least a portion of a distilled liquid derived from the distilled vapor by distilling in the organic amide solvent concentrating step is removed. 
     
     
         7 . A method of manufacturing polyarylene sulfide, comprising:
 (a) a washing step of mixing a solvent containing water with a raw material mixture that contains polyarylene sulfide and an organic amide solvent to obtain a dispersion, dissolving the organic amide solvent in the solvent containing water, and then washing the polyarylene sulfide;   (b) a separating step of solid-liquid separating the dispersion in the washing step to obtain a separated liquid; and   (c) a distilling step of separating the separated liquid into distilled vapor containing a solvent containing water having a smaller amount of the organic amide solvent, and recovered liquid containing a solvent containing water having a larger amount of the organic amide solvent by heating the separated liquid obtained in the separating step; wherein   heating in the distilling step is performed utilizing an increase in temperature based on compressing the distilled vapor and/or an increase in temperature based on compressing a heat medium heat-exchanged with the distilled vapor, and   a distilled liquid containing a condensate of the distilled vapor is used as the solvent containing water in the washing step.   
     
     
         8 . The method according to  claim 7 , wherein the raw material mixture is obtained through:
 a preliminary washing step of mixing polyarylene sulfide or mixture containing polyarylene sulfide with a washing liquid containing an organic amide solvent to obtain a dispersion, and then washing the polyarylene sulfide; and   a preliminary separating step of solid-liquid separating the dispersion in the preliminary washing step, and then separating into a separated liquid and mixture containing polyarylene sulfide.   
     
     
         9 . The method according to  claim 8 , wherein at least one portion of the recovered liquid is used as the washing liquid. 
     
     
         10 . The method according to  claims 1  and  7 , wherein the raw material mixture is obtained through a polymerizing step of polymerization reacting a dihalo aromatic compound and at least one type of sulfur source selected from a group consisting of alkali metal sulfides and alkali metal hydrosulfides, in the organic amide solvent to obtain a reaction liquid containing polyarylene sulfide. 
     
     
         11 . The method according to  claims 1  and  7 , wherein the mixture containing polyarylene sulfide in the preliminary washing step is obtained through a polymerizing step of polymerization reacting a dihalo aromatic compound and at least one type of sulfur source selected from a group consisting of alkali metal sulfides and alkali metal hydrosulfides, in the organic amide solvent to obtain a reaction liquid containing polyarylene sulfide. 
     
     
         12 . The method according to  claims 1  and  7 , wherein a difference between the boiling point of the organic amide solvent and boiling point of water is 50° C. or higher. 
     
     
         13 . Polyarylene sulfide manufactured by the method according to  claims 1  and  7 .