JP2014108964A - Method of manufacturing cyclic polyarylene sulfide - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method of efficiently manufacturing cyclic polyarylene sulfide with high purity by a simple method.SOLUTION: A method of manufacturing cyclic polyarylene sulfide from a reaction mixture containing at least a sulfidation agent (a), a dihalogenated aromatic compound (b) and an organic polar solvent (c) includes a process 1 of heating and reacting a reaction mixture having an arylene unit of 0.80 mol or more and less than 0.95 mol per 1 mol of a sulfur component in the reaction mixture to obtain a reaction mixture (1), a process 2 of adding a dihalogenated aromatic compound (b) so that the arylene unit per 1 mol of the sulfur component in the reaction mixture (1) becomes 0.95 mol or more and less than 1.05 mol, heating and reacting them to obtain a reaction mixture (2), and process 3 of further adding the dihalogenated aromatic compound (b) so that the arylene unit per 1 mol of the sulfur component in the reaction mixture (2) becomes 1.05 mol or more and less than 1.50 mol and further reacting them after the process 2 to obtain a reaction product.

Description

  The present invention relates to a method for producing a cyclic polyarylene sulfide. More specifically, a method for producing a cyclic polyarylene sulfide by heating and reacting a reaction mixture containing at least a sulfidizing agent, a dihalogenated aromatic compound and an organic polar solvent, wherein the cyclic polyarylene sulfide has a high purity. It is related with the method of manufacturing efficiently by a simple method.

  Aromatic cyclic compounds have attracted attention in recent years due to the properties resulting from their cyclicity, ie, the specificity derived from their structure. Specifically, it is an effective monomer for use in high-functional material applications and functional materials, for example, as a compound having inclusion ability, and for the synthesis of high-molecular-weight linear polymers by ring-opening polymerization. It is expected to be used as Cyclic polyarylene sulfide (hereinafter, polyarylene sulfide may be abbreviated as PAS) also belongs to the category of aromatic cyclic compounds and is a notable compound as described above.

  As a method for producing a cyclic polyarylene sulfide, for example, a method in which a diaryl disulfide compound is oxidatively polymerized under ultradilution conditions has been proposed (see, for example, Patent Document 1). In this method, it is presumed that cyclic polyarylene sulfide is produced with high selectivity, and that only a small amount of linear polyarylene sulfide is produced, and cyclic polyarylene sulfide is certainly obtained with high production rate. However, in this method, it is essential to carry out the reaction under ultra-dilution conditions, and the amount of cyclic polyarylene sulfide obtained per unit volume of the reaction vessel is very small, and cyclic polyarylene sulfide can be obtained efficiently. From this point of view, it was a method with many problems. Moreover, since the reaction temperature of this method is around room temperature, the reaction requires a long time of several tens of hours, and the method is inferior in productivity. Furthermore, the linear polyarylene sulfide produced as a by-product by the method has a low molecular weight including a disulfide bond derived from the starting diaryl disulfide, and has low thermal stability and no practical value. In addition, the linear polyarylene sulfide produced as a by-product in this method has a molecular weight close to that of the target cyclic polyarylene sulfide, so that it is difficult to separate the cyclic polyarylene sulfide and the produced linear polyarylene sulfide. It was extremely difficult to efficiently obtain a highly pure cyclic polyarylene sulfide. In addition, this method requires an equivalent amount of an expensive oxidizing agent such as dichlorodicyanobenzoquinone as the raw material diaryl disulfide for the progress of oxidative polymerization, and cyclic polyarylene sulfide cannot be obtained at low cost. As another method for oxidative polymerization of diaryl disulfide compounds under ultra-dilution conditions, a method in which oxidative polymerization is performed in the presence of a metal catalyst and oxygen is used as an oxidizing agent has been proposed. In this method, the oxidizing agent is inexpensive, but there are many problems such that the reaction is difficult to control and a large amount of by-product oligomers are produced, and the reaction requires a very long time. As described above, the oxidative polymerization method of the diaryl disulfide compound under ultradilution conditions cannot efficiently obtain a cyclic polyarylene sulfide having a high purity at any cost.

  As another method for producing cyclic polyarylene sulfide, a method in which a copper salt of 4-bromothiophenol is heated under ultra-diluted conditions in quinoline is disclosed. In this method as well, the ultra-dilution conditions are indispensable as in the case of Patent Document 1, and a long time is required for the reaction, and the method is extremely low in productivity. Furthermore, in this method, it is difficult to separate the by-produced copper bromide from the product cyclic polyarylene sulfide, and the resulting cyclic polyarylene sulfide has low purity (see, for example, Patent Document 2). .)

  As a method for producing cyclic polyarylene sulfide from a general-purpose raw material at a high production rate, a sulfidizing agent and a dihalogenated aromatic compound are used in an organic polarity of 1.25 liters or more with respect to 1 mol of a sulfur component of the sulfidizing agent. The method of making it react in a solvent is disclosed (for example, refer patent document 3). However, in this method, since the production rate of cyclic polyarylene sulfide relative to the raw material monomer is low and a large amount of linear polyarylene sulfide is by-produced, improvement has been desired.

  As a method for obtaining a cyclic polyarylene sulfide at a high production rate, a dihalogenated aromatic compound such as 1,4-bis- (4′-bromophenylthio) benzene and sodium sulfide are refluxed in N-methylpyrrolidone at a reflux temperature. Has been disclosed (for example, see Non-Patent Document 1). In this method, it can be estimated that a cyclic polyarylene sulfide can be obtained because the amount of the organic polar solvent with respect to 1 mol of the sulfur component in the reaction mixture is 1.25 liters or more. However, since this method does not use linear polyarylene sulfide as a raw material, it is necessary to use a large amount of a dihalogenated aromatic compound, and since the dihalogenated aromatic compound used is a very special compound, It was a method with poor industrial feasibility, and improvement was desired.

  As a method for solving the above-mentioned problem, a method in which linear polyarylene sulfide, a sulfidizing agent and a dihalogenated aromatic compound are reacted by heating in an organic polar solvent of 1.25 liters or more per mole of sulfur component in the reaction mixture. (For example, refer to Patent Document 4). In this method, the amount of monomer to be used can be reduced because linear polyarylene sulfide is used as a raw material. Therefore, the production rate of cyclic polyarylene sulfide with respect to the monomer is improved, and industrial feasibility can be expected. . However, in this method, only a method in which all reaction raw materials, that is, linear polyarylene sulfide, a sulfidizing agent, a dihalogenated aromatic compound, and an organic polar solvent are charged and reacted together has been verified. No verification has been made on the improvement of the yield of cyclic polyarylene sulfide and the reduction of impurities by the addition of a dihalogenated aromatic compound.

  As a method for producing a cyclic polyarylene sulfide in a multi-stage process with the addition of a dihalogenated aromatic compound, a linear polyarylene sulfide, a sulfidizing agent, an organic polar solvent, and a sulfur component of 0.1 mol per sulfur component of the sulfidizing agent are used. Conduct reaction (A) in which the reaction mixture containing less than 9 mol of dihalogenated aromatic compound is heated, add dihalogenated aromatic compound, and 1.25 liters or more of organic polar solvent per mol of sulfur component in the reaction mixture A method of performing the reaction (B) of heating in the medium is disclosed (for example, Patent Document 5). This method is characterized in that the low molecular weight prepolymer produced in the reaction (A) is cyclized by adding a dihalogenated aromatic compound in the reaction (B). In this method, in order to efficiently produce a prepolymer, it is preferable that substantially no dihalogenated aromatic compound is present in the reaction mixture in the reaction (A). Only methods that did not include were verified. In order to efficiently produce the prepolymer, the organic polar solvent in the reaction mixture in the reaction (A) is preferably less than 1.25 liters per mole of sulfur component. Only a method in which the organic polar solvent was 1 liter per mole of sulfur component has been verified. Therefore, as in the present invention, the dihalogenated aromatic compound is allowed to actively coexist in the reaction mixture before addition of the dihalogenated aromatic compound, and the organic polar solvent is used in an amount of 1. The effect on the production rate when producing cyclic polyarylene sulfide under more dilute conditions of 25 liters or more was unknown.

  Here, in recovering the cyclic polyarylene sulfide in Patent Documents 3 and 4, the cyclic polyarylene sulfide is first removed by removing a part or most of the organic polar solvent from the reaction mixture obtained by the reaction. And a mixed solid mainly composed of linear polyarylene sulfide is recovered, and then a solution containing cyclic polyarylene sulfide is prepared by contacting with a solvent capable of dissolving cyclic polyarylene sulfide, and then dissolved from the solution. A method for obtaining a cyclic polyarylene sulfide by removing the solvent used is disclosed.

  Similar to the above recovery method, a highly pure cyclic polyarylene sulfide can be obtained by dissolving a polyarylene sulfide mixture containing at least linear polyarylene sulfide and cyclic polyarylene sulfide, and dissolving the cyclic polyarylene sulfide. A method is disclosed in which a solution containing a cyclic polyarylene sulfide is prepared by contacting with a possible solvent, and then a cyclic polyarylene sulfide is obtained from the solution (see, for example, Patent Document 6). Although these methods can surely obtain a high-purity cyclic polyarylene sulfide, in order to obtain a high-purity cyclic polyarylene sulfide, a cyclic polyarylene sulfide, a linear polyarylene sulfide and an organic polar solvent are used. A step of producing a reaction mixture, a step of removing a polar organic solvent from the reaction mixture to produce a mixed solid containing cyclic polyarylene sulfide and a linear polyarylene sulfide, and contacting the mixed solid with a solvent The step of obtaining a solution containing arylene sulfide and the step of removing the solvent from this solution are essential and can be said to be very complicated.

  As a method for recovering cyclic polyarylene sulfide as described above, that is, as a method for recovering highly pure cyclic polyarylene sulfide by an efficient and simple method, at least a sulfidizing agent and dihalogenation in an organic polar solvent A method for recovering a cyclic polyarylene sulfide from a reaction mixture containing at least a linear polyarylene sulfide and a cyclic polyarylene sulfide obtained by bringing an aromatic compound into contact with each other, wherein the reaction mixture is an organic polar solvent. A method for recovering a cyclic polyarylene sulfide characterized by removing an organic polar solvent from a filtrate obtained by solid-liquid separation in a temperature range below the boiling point in pressure (see, for example, Patent Document 7), and at least polyarylene Sulfides, cyclic polyarylene sulfides and organic electrodes How to from a mixture comprising the solvent and solid-liquid separation After distilling off part of the organic polar solvent recovery cyclic polyarylene sulfide (for example, see Patent Document 8) have been disclosed. These methods separate and recover the target cyclic polyarylene sulfide by a simple method of solid-liquid separation, and are certainly methods for improving the above-mentioned problems of the prior art. In the step of obtaining a reaction product containing polyarylene sulfide, addition of a dihalogenated aromatic compound, which is a feature of the present invention, and further reaction are not performed, so that the reaction product is separated for a long time in the solid-liquid separation process. The problem of requiring time still remains, and the purity of the obtained cyclic polyarylene sulfide is insufficient, and improvement has been strongly desired.

Japanese Patent No. 3200027 US Pat. No. 5,869,599 JP 2009-30012 A International Publication No. 2008/105438 JP 2011-068885 A JP 2007-231255 A JP 2009-149863 A JP 2010-0375550 A Bull. Acad. Sci., Vol.39, p.763-766, 1990

  This invention solves the subject of the said prior art, and makes it a subject to provide the method of manufacturing a highly purified cyclic polyarylene sulfide efficiently by a simple method.

SUMMARY An advantage of some aspects of the invention is to solve at least a part of the problems described above, and the invention can be implemented as the following forms.
1. A reaction mixture comprising at least a sulfidizing agent (a), a dihalogenated aromatic compound (b) and an organic polar solvent (c), wherein 1.25 liters or more and 50 liters per mole of sulfur component in the reaction mixture A method for producing a cyclic polyarylene sulfide by heating and reacting the reaction mixture containing the following organic polar solvent (c):
The dihalogenated aromatic compound (b) in the reaction mixture is heated by heating the reaction mixture having an arylene unit of 0.80 mol or more and less than 0.95 mol per mol of the sulfur component in the reaction mixture. A step 1 of obtaining a reaction mixture (1) by reacting until the amount of arylene units in the reaction mixture is 10 mol% or less based on the amount;
Following step 1, the dihalogenated aromatic compound (b) is added so that the arylene unit per mole of sulfur component in the reaction mixture (1) is 0.95 mol or more and less than 1.05 mol, and the dihalogenated aromatic compound is added. A step 2 in which the group compound (b) is reacted by heating until the amount of the arylene unit is 10 mol% or less based on the amount of the arylene unit, and a reaction mixture (2) is obtained;
Following step 2, the dihalogenated aromatic compound (b) is added to the reaction mixture (2) so that the number of arylene units per mole of sulfur component is 1.05 mol or more and 1.50 mol or less, followed by further heating. And a step 3 of obtaining a reaction product containing at least a cyclic polyarylene sulfide and a linear polyarylene sulfide, and producing a cyclic polyarylene sulfide.
2. The ring according to item 1, wherein in step 1, the dihalogenated aromatic compound (b) in the reaction mixture is reacted until it becomes 7 mol% or less based on the amount of the arylene unit in the reaction mixture. A process for producing a polyarylene sulfide.
3. The cyclic compound according to item 1 or 2, wherein in step 2, the dihalogenated aromatic compound (b) is reacted by heating to 7 mol% or less based on the amount of the arylene unit. A method for producing polyarylene sulfide.
4). Following step 3,
Step 4 of obtaining a filtrate containing the cyclic polyarylene sulfide and the organic polar solvent (c) is performed by solid-liquid separation of the reaction product in a temperature range below the boiling point of the organic polar solvent (c) at normal pressure. The method for producing the cyclic polyarylene sulfide according to any one of Items 1 to 3.
5. Item 5. The method for producing cyclic polyarylene sulfide according to any one of Items 1 to 4, wherein the reaction mixture further contains a linear polyarylene sulfide (d).
6). 6. The method for producing cyclic polyarylene sulfide according to item 5, wherein the reaction mixture contains linear polyarylene sulfide (d) at the start of the reaction in Step 1.
7). A method for producing the cyclic polyarylene sulfide according to item 5 or 6,
A reaction mixture containing at least a sulfidizing agent (a), a dihalogenated aromatic compound (b), and an organic polar solvent (c), wherein 1.25 to 50 liters per mole of sulfur component in the reaction mixture A reaction mixture comprising an organic polar solvent (c) of
The reaction mixture in which the number of arylene units per mole of sulfur component in the reaction mixture is 0.80 mol or more and less than 0.95 mol is heated, and the dihalogenated aromatic compound (b) in the reaction mixture is heated in the reaction mixture. A step 1 of obtaining a reaction mixture (1) by reacting until the amount of the arylene unit is 10 mol% or less based on the amount of the arylene unit;
Following step 1, the dihalogenated aromatic compound (b) is added so that the arylene unit per mole of sulfur component in the reaction mixture (1) is 0.95 mol or more and less than 1.05 mol, and the dihalogenated aromatic compound is added. A step 2 in which the group compound (b) is reacted by heating until the amount of the arylene unit is 10 mol% or less based on the amount of the arylene unit, and a reaction mixture (2) is obtained;
Following step 2, the dihalogenated aromatic compound (b) is added to the reaction mixture (2) so that the number of arylene units per mole of sulfur component is 1.05 mol or more and 1.50 mol or less, followed by further heating. Step 3 to obtain a reaction product containing at least cyclic polyarylene sulfide and linear polyarylene sulfide;
The linear polyarylene sulfide obtained by separating the cyclic polyarylene sulfide from the polyarylene sulfide mixture containing the cyclic polyarylene sulfide and the linear polyarylene sulfide obtained by heating and reacting by a method including A process for producing a cyclic polyarylene sulfide using the arylene sulfide as the linear polyarylene sulfide (d).
8). A method for producing the cyclic polyarylene sulfide according to item 5 or 6,
A reaction mixture comprising at least a linear polyarylene sulfide (d), a sulfidizing agent (a), a dihalogenated aromatic compound (b) and an organic polar solvent (c), and relative to 1 mol of a sulfur component in the reaction mixture Reaction mixture containing 1.25 liters to 50 liters of organic polar solvent (c),
The reaction mixture in which the number of arylene units per mole of sulfur component in the reaction mixture is 0.80 mol or more and less than 0.95 mol is heated, and the dihalogenated aromatic compound (b) in the reaction mixture is heated in the reaction mixture. A step 1 of obtaining a reaction mixture (1) by reacting until the amount of the arylene unit is 10 mol% or less based on the amount of the arylene unit;
Following step 1, the dihalogenated aromatic compound (b) is added so that the arylene unit per mole of sulfur component in the reaction mixture (1) is 0.95 mol or more and less than 1.05 mol, and the dihalogenated aromatic compound is added. A step 2 in which the group compound (b) is reacted by heating until the amount of the arylene unit is 10 mol% or less based on the amount of the arylene unit, and a reaction mixture (2) is obtained;
Following step 2, the dihalogenated aromatic compound (b) is added to the reaction mixture (2) so that the number of arylene units per mole of sulfur component is 1.05 mol or more and 1.50 mol or less, followed by further heating. Step 3 to obtain a reaction product containing at least cyclic polyarylene sulfide and linear polyarylene sulfide;
The linear polyarylene sulfide obtained by separating the cyclic polyarylene sulfide from the polyarylene sulfide mixture containing the cyclic polyarylene sulfide and the linear polyarylene sulfide obtained by heating and reacting by a method including A process for producing a cyclic polyarylene sulfide using the arylene sulfide as the linear polyarylene sulfide (d).
9. When linear polyarylene sulfide is contained in the reaction mixture at the start of the reaction in Step 1, the content of the linear polyarylene sulfide is 0.001 mol or more per mol of sulfur component of the sulfidizing agent in the reaction mixture. Item 7. The method for producing a cyclic polyarylene sulfide according to Item 5 or 6, wherein the number is less than a mole.
10. At the end of step 1, the content of the aryl monothiolate compound in the reaction mixture (1) is less than 0.01 mole per mole of arylene units in the reaction mixture (1). 10. The method for producing a cyclic polyarylene sulfide according to any one of items 9 to 9.
11. The method for producing a cyclic polyarylene sulfide according to any one of Items 1 to 10, wherein the heating in Step 2 and Step 3 is performed at a temperature higher than the heating temperature in Step 1.

  ADVANTAGE OF THE INVENTION According to this invention, the method of manufacturing a highly purified cyclic polyarylene sulfide efficiently by a simple method can be provided.

  Hereinafter, embodiments of the present invention will be described in detail. Embodiments of the present invention relate to a method for producing cyclic polyarylene sulfide (hereinafter sometimes abbreviated as cyclic PAS).

(1) Sulfidation agent The sulfidation agent used in the embodiment of the present invention is any one that can introduce a sulfide bond into a dihalogenated aromatic compound and that can produce an arylene thiolate by acting on an arylene sulfide bond. Good examples include alkali metal sulfides, alkali metal hydrosulfides, and hydrogen sulfide.

  Specific examples of the alkali metal sulfide include lithium sulfide, sodium sulfide, potassium sulfide, rubidium sulfide, cesium sulfide and a mixture of two or more of these. Of these, lithium sulfide and / or sodium sulfide are preferable, and sodium sulfide is more preferably used. These alkali metal sulfides can be used as hydrates or aqueous mixtures or in the form of anhydrides. The aqueous mixture refers to an aqueous solution, a mixture of an aqueous solution and a solid component, or a mixture of water and a solid component. Since generally available inexpensive alkali metal sulfides are hydrates or aqueous mixtures, it is preferred to use such forms of alkali metal sulfides.

  Specific examples of the alkali metal hydrosulfide include, for example, lithium hydrosulfide, sodium hydrosulfide, potassium hydrosulfide, lithium hydrosulfide, rubidium hydrosulfide, cesium hydrosulfide, and a mixture of two or more thereof. Of these, lithium hydrosulfide and / or sodium hydrosulfide are preferable, and sodium hydrosulfide is more preferably used.

  Moreover, the alkali metal sulfide produced | generated in a reaction system from an alkali metal hydrosulfide and an alkali metal hydroxide can also be used. Alternatively, an alkali metal sulfide prepared by previously contacting an alkali metal hydrosulfide and an alkali metal hydroxide can be used. These alkali metal hydrosulfides and alkali metal hydroxides can be used in the form of compounds selected from hydrates, aqueous mixtures, and anhydrides. Hydrates or aqueous mixtures are preferred from the standpoint of availability and cost.

  Furthermore, alkali metal sulfides generated in the reaction system from alkali metal hydroxides such as lithium hydroxide and sodium hydroxide and hydrogen sulfide can also be used. Further, alkali metal sulfides prepared by previously contacting alkali metal hydroxides such as lithium hydroxide and sodium hydroxide with hydrogen sulfide can also be used. Hydrogen sulfide can be used in any form of gas, liquid, and aqueous solution.

  In the embodiment of the present invention, the amount of the sulfidizing agent is determined based on the actual charge amount when a partial loss of the sulfidizing agent occurs before the reaction with the dihalogenated aromatic compound due to dehydration operation or the like. It shall mean the remaining amount after deduction.

  An alkali metal hydroxide and / or an alkaline earth metal hydroxide can be used in combination with the sulfidizing agent. Specific examples of the alkali metal hydroxide include sodium hydroxide, potassium hydroxide, lithium hydroxide, rubidium hydroxide and cesium hydroxide. Specific examples of the alkaline earth metal hydroxide include water. Although calcium oxide, magnesium hydroxide, strontium hydroxide, and barium hydroxide are mentioned, sodium hydroxide is preferably used from the viewpoint of availability. In addition, these may be used independently and may be used as a 2 or more types of mixture. These alkali metal hydroxides and / or alkaline earth metal hydroxides can be used in any shape such as a solid state or an aqueous solution state.

  When an alkali metal hydrosulfide is used as the sulfiding agent, it is particularly preferable to use an alkali metal hydroxide at the same time. In this case, the amount of alkali metal hydroxide used can be 0.95 mol or more, preferably 1.00 mol or more, more preferably 1.005 mol, per 1 mol of alkali metal hydrosulfide. That's it. Moreover, it can be 1.50 mol or less, Preferably it is 1.25 mol or less, More preferably, it is 1.200 mol or less. When hydrogen sulfide is used as the sulfiding agent, it is particularly preferable to use an alkali metal hydroxide at the same time. In this case, the amount of the alkali metal hydroxide used can be 2.0 mol or more, preferably 2.01 mol or more, more preferably 2.04 mol or more with respect to 1 mol of hydrogen sulfide. . Moreover, it can be 3.0 mol or less, Preferably it is 2.50 mol or less, More preferably, it is 2.40 mol or less.

(2) Dihalogenated aromatic compound The dihalogenated aromatic compound used in the embodiment of the present invention is an aromatic compound having an arylene group which is a divalent group of an aromatic ring and two halogeno groups. One mole of the dihalogenated aromatic compound has 1 mole of an arylene unit and 2 moles of a halogeno group. For example, compounds having a phenylene group which is a divalent group of a benzene ring as an arylene group and two halogeno groups include p-dichlorobenzene, o-dichlorobenzene, m-dichlorobenzene, p-dibromobenzene, o-dibromo. Mention may be made of dihalogenated benzenes such as benzene, m-dibromobenzene, 1-bromo-4-chlorobenzene, and 1-bromo-3-chlorobenzene. Further, examples of the dihalogenated aromatic compound include 1-methoxy-2,5-dichlorobenzene, 1-methyl-2,5-dichlorobenzene, 1,4-dimethyl-2,5-dichlorobenzene, and 1,3-dimethyl. Mention may also be made of compounds containing substituents other than halogen, such as -2,5-dichlorobenzene and 3,5-dichlorobenzoic acid. Especially, the dihalogenated aromatic compound which has p-dihalogenated benzene represented by p-dichlorobenzene as a main component is preferable. Particularly preferably, it contains 80 to 100 mol%, more preferably 90 to 100 mol% of p-dichlorobenzene. It is also possible to use a combination of two or more different dihalogenated aromatic compounds in order to obtain a cyclic PAS copolymer.

(3) Linear polyarylene sulfide In the embodiment of the present invention, the linear polyarylene sulfide (hereinafter sometimes abbreviated as linear PAS) is composed mainly of a repeating unit of formula, — (Ar—S) —. The unit is preferably a linear homopolymer or a linear copolymer containing 80 mol% or more of the repeating unit. Ar includes units represented by the following formulas (A) to (L), among which the formula (A) is particularly preferable.

(In the formula, R1 and R2 are substituents selected from hydrogen, an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, and a halogen group, and R1 and R2 are the same or different. May be.)

  As long as this repeating unit is a main structural unit, it can contain a small amount of branching units or crosslinking units represented by the following formulas (M) to (P). The amount of copolymerization of these branched units or cross-linked units is preferably in the range of 0 to 1 mol% with respect to 1 mol of the main structural unit represented by-(Ar-S)-.

  Further, the linear PAS in the embodiment of the present invention may be any of a random copolymer, a block copolymer and a mixture thereof containing the above repeating unit.

  Typical examples thereof include polyphenylene sulfide, polyphenylene sulfide sulfone, polyphenylene sulfide ketone, random copolymers thereof, block copolymers thereof and mixtures thereof. A particularly preferred linear PAS is a p-phenylene sulfide unit as the main structural unit of the polymer.

Of polyphenylene sulfide (hereinafter sometimes abbreviated as PPS), polyphenylene sulfide sulfone, and polyphenylene sulfide ketone.

  In the method for producing the cyclic PAS according to the embodiment of the present invention, linear PAS can be used as a raw material. The melt viscosity of the linear PAS used in that case is not particularly limited, but the melt viscosity of a general linear PAS is exemplified by a range of 0.1 to 1000 Pa · s (300 ° C., shear rate 1000 / sec). A range of 0.1 to 500 Pa · s can be exemplified. Further, the molecular weight of the linear PAS is not particularly limited, and general PAS can be used. The weight average molecular weight of such a PAS can be 5,000 or more, preferably 7,500 or more, and more preferably 10,000 or more. Further, the weight average molecular weight of PAS can be 1,000,000 or less, preferably 500,000 or less, and more preferably 100,000 or less. In general, the lower the weight average molecular weight, the higher the solubility in an organic polar solvent. Therefore, there is an advantage that the time required for the reaction can be shortened, but within the above-mentioned range, it can be used without any substantial problem.

  The production method of such a linear PAS is not particularly limited, and any production method can be used. For example, an aromatic compound or thiophene containing at least one nucleus-substituted halogen and an alkali metal monosulfide represented by Japanese Patent Publication No. 45-3368, Japanese Patent Publication No. 52-12240 and Japanese Patent Publication No. 63-3375 Can be produced by a method in which the reaction is carried out at an elevated temperature in a polar organic solvent. Preferably, linear PAS can be obtained by bringing a sulfidizing agent and a dihalogenated aromatic compound into contact with each other in an organic polar solvent, as represented by, for example, JP-A No. 05-163349. In addition, molded products and molding waste using PAS produced by these methods, or waste plastics and off-spec products derived from PAS produced by these methods can be used widely as linear PAS.

  In general, since the production of a cyclic compound is a competitive reaction between the production of a cyclic compound and the production of a linear compound, in a method aimed at producing a cyclic polyarylene sulfide, In addition to polyarylene sulfide, linear polyarylene sulfide is produced as a by-product. In the embodiment of the present invention, such a by-product linear polyarylene sulfide can be used as a raw material without any problem. For example, the method for producing cyclic PAS represented by Patent Document 3 described above, that is, an organic polar solvent having a sulfidizing agent and a dihalogenated aromatic compound in an amount of 1.25 liters or more per 1 mol of the sulfur component of the sulfidizing agent. By using the production method in which the reaction is carried out by heating, the linear polyarylene sulfide obtained by separating the cyclic polyarylene sulfide from the obtained polyarylene sulfide mixture containing the cyclic polyarylene sulfide and the linear polyarylene sulfide. The method using polyarylene sulfide as a raw material is a particularly preferable method. In addition, the method for producing cyclic PAS represented by Patent Document 4 described above, that is, linear polyarylene sulfide, sulfidizing agent, and dihalogenated aromatic compound are added in an amount of 1. with respect to 1 mol of sulfur component in the reaction mixture. Separation of cyclic polyarylene sulfide from the resulting polyarylene sulfide mixture containing cyclic polyarylene sulfide and linear polyarylene sulfide by a production method in which the reaction is conducted by heating using an organic polar solvent of 25 liters or more. The method using the linear polyarylene sulfide obtained by the above as a raw material is also a preferable method.

  And a reaction mixture comprising at least a linear polyarylene sulfide (d), a sulfidizing agent (a), a dihalogenated aromatic compound (b) and an organic polar solvent (c), wherein 1 mol of a sulfur component in the reaction mixture In a process for producing a cyclic polyarylene sulfide by heating a reaction mixture containing 1.25 liters to 50 liters of an organic polar solvent (c) relative to 1 mol of sulfur component in the reaction mixture The reaction mixture having an arylene unit of 0.80 mol or more and less than 0.95 mol is heated and reacted to obtain a reaction mixture (1) (step 1), followed by step 1 and then in the reaction mixture (1). The dihalogenated aromatic compound (b) is added and heated so that the number of arylene units per mole of sulfur component is 0.95 mol or more and less than 1.05 mol. A reaction mixture (2) is obtained by the reaction (step 2). Next to step 2, the arylene unit per mole of sulfur component in the reaction mixture (2) is 1.05 mol or more and 1.50 mol or less. The cyclic polyarylene sulfide is separated from the polyarylene sulfide mixture containing the cyclic polyarylene sulfide and the linear polyarylene sulfide obtained by further reacting after adding the dihalogenated aromatic compound (b) to It is a particularly preferable method to use the linear polyarylene sulfide obtained by the above method.

  Conventionally, a linear compound by-produced in the production of a cyclic compound, for example, a cyclic polyarylene sulfide, that is, a low molecular weight linear polyarylene sulfide has been discarded as having no utility value. Therefore, in the production of the cyclic compound, there are problems that the amount of waste resulting from the by-product linear compound is large and the production rate with respect to the raw material monomer is low. In the embodiment of the present invention, this byproduct linear polyarylene sulfide can be used as a raw material, and this is a viewpoint that enables a significant reduction in the amount of waste and a dramatic improvement in the production rate with respect to the raw material monomer. It is very significant.

  In addition, there is no restriction | limiting in particular in the form of linear polyarylene sulfide, A dry powder form, a granular form, a granular form, and a pellet form may be sufficient. The linear polyarylene sulfide can be used in a state containing an organic polar solvent which is a reaction solvent, and can also be used in a state containing a third component which does not essentially inhibit the reaction. Examples of such a third component include inorganic fillers and alkali metal halides. Here, the alkali metal halide includes any combination of alkali metals (ie, lithium, sodium, potassium, rubidium and cesium) and halogens (ie, fluorine, chlorine, bromine, iodine and astatine). Specific examples include lithium chloride, sodium chloride, potassium chloride, lithium bromide, sodium bromide, potassium bromide, lithium iodide, sodium iodide, potassium iodide, and cesium fluoride. Preferable examples include alkali metal halides generated by the reaction of the aforementioned sulfiding agent and dihalogenated aromatic compound. Alkali metal halides resulting from combinations of sulfidizing agents and dihalogenated aromatic compounds that are generally readily available include lithium chloride, sodium chloride, potassium chloride, lithium bromide, sodium bromide, potassium bromide and iodide. Sodium can be exemplified, and sodium chloride, potassium chloride, sodium bromide, and potassium bromide can be exemplified as preferred, and sodium chloride is more preferred. It is also possible to use linear polyarylene sulfide in the form of a resin composition containing an inorganic filler or an alkali metal halide.

  In the method for producing the cyclic polyarylene sulfide according to the embodiment of the present invention, linear PAS is generated as a by-product as described above. The melt viscosity of the linear PAS produced in the embodiment of the present invention is not particularly limited, but the melt viscosity of a general linear PAS is 0.1 to 1000 Pa · s (300 ° C., shear rate 1000 / sec). A range can be illustrated, and it can be said that a range of 0.1 to 500 Pa · s tends to be generated. Further, the molecular weight of the linear PAS is not particularly limited, but the weight average molecular weight of a general PAS can be exemplified as 1,000 to 1,000,000, and the production of the cyclic polyarylene sulfide of the embodiment of the present invention The linear PAS produced by the method tends to be in the range of 2,500 to 500,000, and tends to be in the range of 5,000 to 100,000. In general, the higher the weight average molecular weight, the more strongly the characteristics as linear PAS are expressed. Therefore, in the separation of cyclic PAS and linear PAS described later, the separation tends to be easily performed. It can be used without any essential problems.

(4) Organic polar solvent In the embodiment of the present invention, an organic polar solvent is used when a reaction between a sulfidizing agent and a dihalogenated aromatic compound is performed, or when a reaction product obtained by the reaction is subjected to solid-liquid separation. However, the organic polar solvent is preferably an organic amide solvent. Specific examples include N-alkylpyrrolidones such as N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, and N-cyclohexyl-2-pyrrolidone, N-methyl-ε-caprolactam, and ε-caprolactam. Caprolactams, aprotic organic solvents represented by 1,3-dimethyl-2-imidazolidinone, N, N-dimethylacetamide, N, N-dimethylformamide, and hexamethylphosphoric triamide, and mixtures thereof Are preferably used because of high stability of the reaction. Among these, N-methyl-2-pyrrolidone and 1,3-dimethyl-2-imidazolidinone are preferably used. In the embodiment of the present invention, the amount of the organic polar solvent used in the reaction of at least the sulfidizing agent, the dihalogenated aromatic compound and the organic polar solvent is 1 with respect to 1 mol of the sulfur component in the reaction mixture. It is 25 liters or more and 50 liters or less. The preferable lower limit of the amount of the organic polar solvent used is 1.5 liters or more, more preferably 2 liters or more. On the other hand, the upper limit is preferably 20 liters or less, and more preferably 15 liters or less. Here, the amount of solvent used is based on the volume of the solvent under normal temperature and pressure. When the amount of the organic polar solvent used per mole of sulfur component is less than 1.25 liters, the production rate of the cyclic polyarylene sulfide produced by the reaction of the sulfidizing agent and the dihalogenated aromatic compound is extremely low. Since the production rate of linear polyarylene sulfide by-produced accompanying the production of cyclic polyarylene sulfide is increased, the productivity of cyclic polyarylene sulfide per unit raw material is poor. Here, the production rate of cyclic polyarylene sulfide refers to the sulfur-containing raw material used in the preparation of the reaction mixture in the production of cyclic polyarylene sulfide described in detail later (sulfiding agent and, if used, linear). The cyclic polyarylene sulfide actually produced in the production of the cyclic polyarylene sulfide relative to the amount of the cyclic polyarylene sulfide produced when it is assumed that all sulfur components contained in the cyclic polyarylene sulfide) are converted into the cyclic polyarylene sulfide. It is the ratio of the amount of arylene sulfide. If the production rate of cyclic polyarylene sulfide is 100%, it means that all the sulfur components in the sulfur-containing raw material used have been converted to cyclic polyarylene sulfide.

  Here, the production rate of the cyclic polyarylene sulfide is preferable from the viewpoint of converting the used sulfur-containing raw material into the target product (cyclic polyarylene sulfide) more efficiently as the amount of the organic polar solvent used is larger. However, when the amount of the organic polar solvent used is extremely increased in the production of the cyclic polyarylene sulfide in order to achieve an extremely high production rate, the amount of cyclic PAS produced per unit volume of the reaction vessel decreases. There is a tendency, and the time required for the reaction tends to increase. Furthermore, when performing the operation of isolating and recovering the cyclic polyarylene sulfide, if the amount of the organic polar solvent used is too much, the amount of the cyclic polyarylene sulfide per unit amount in the reaction product becomes very small. The collection operation becomes difficult. It is preferable to make it the usage-amount range of an organic polar solvent mentioned above from a viewpoint of making the production | generation rate and productivity of cyclic polyarylene sulfide compatible.

  It should be noted that the amount of solvent used in the production of general cyclic compounds is often very large, and in many cases the cyclic compound cannot be obtained efficiently within the preferred amount range of embodiments of the present invention. In the embodiment of the present invention, cyclic PAS can be efficiently obtained even under conditions where the amount of solvent used is relatively small, that is, when the amount is not more than the above-mentioned upper limit value of the preferred amount of solvent used, compared to the case of general cyclic compound production. It is done. The reason for this is not clear at the present time, but in the method of the embodiment of the present invention, the reaction is carried out above the reflux temperature of the reaction mixture, so that the reaction efficiency is very high and the consumption rate of the raw material is high. It is presumed that it works properly. Here, the usage amount of the organic polar solvent in the reaction mixture is an amount obtained by subtracting the organic polar solvent removed from the reaction system from the organic polar solvent introduced into the reaction system.

(5) Cyclic polyarylene sulfide The cyclic polyarylene sulfide in the embodiment of the present invention is a cyclic compound having a repeating unit of the formula-(Ar-S)-as a main structural unit, preferably the repeating unit. Can be exemplified by compounds such as those represented by the following general formula (Q).

  Here, examples of Ar can include units represented by the above formulas (A) to (L), among which the formulas (A) to (C) are preferable, and the formulas (A) and (B) are More preferred is formula (A).

  In addition, in cyclic polyarylene sulfide, repeating units, such as said Formula (A)-Formula (L), may be included at random, may be included in a block, and any of those mixtures may be sufficient. Typical examples of these include cyclic polyphenylene sulfide, cyclic polyphenylene sulfide sulfone, cyclic polyphenylene sulfide ketone, cyclic random copolymers containing these, cyclic block copolymers, and mixtures thereof. . Particularly preferred cyclic polyarylene sulfides include p-phenylene sulfide units as the main structural unit.

Is a cyclic polyphenylene sulfide containing 80 mol% or more, particularly 90 mol% or more.

  Although there is no restriction | limiting in particular in the repeating number m in the said formula (Q) of cyclic polyarylene sulfide, The mixture of 4-50 is preferable, 4-30 are more preferable, and 4-25 are still more preferable. As described later, a polyarylene sulfide prepolymer containing a cyclic polyarylene sulfide is used as a raw material and a high molecular weight polyarylene sulfide (hereinafter, a high molecular weight polyarylene sulfide obtained using a polyarylene sulfide prepolymer as a raw material is simply converted into (Also referred to as arylene sulfide or PAS), it is desirable that the polyarylene sulfide prepolymer is heated at a temperature at which the polyarylene sulfide prepolymer melts, so that the polyarylene sulfide can be obtained efficiently. It becomes.

  Here, when the cyclic polyarylene sulfide repeat number m is in the above range, the cyclic PAS tends to have a melting temperature of 275 ° C. or lower, preferably 260 ° C. or lower, more preferably 255 ° C. or lower. Therefore, the melting temperature of such a polyarylene sulfide prepolymer containing cyclic PAS also tends to be lowered accordingly. Therefore, when the range of m of the cyclic PAS is in the above range, it is desirable that the heating temperature of the polyarylene sulfide prepolymer can be set low in the production of the polyarylene sulfide. Here, the melting temperature of cyclic PAS and polyarylene sulfide is the endotherm observed when the temperature is raised to 360 ° C. at a scanning rate of 20 ° C./min after holding at 50 ° C. for 1 minute with a suggested scanning calorimeter. Indicates the peak temperature of the peak.

  The cyclic polyarylene sulfide in the embodiment of the present invention may be either a single compound having a single repeating number or a mixture of cyclic polyarylene sulfides having different repeating numbers, but cyclic compounds having different repeating numbers. A mixture of polyarylene sulfides is preferred because it has a lower melting solution temperature and a smaller amount of heat required for melting than a single compound having a single repeating number. In the cyclic polyarylene sulfide of the embodiment of the present invention, the content of the cyclic PAS of m = 6 in the formula (A) with respect to the total amount of the cyclic polyarylene sulfide is preferably less than 50% by weight, It is more preferably less than 40% by weight and even more preferably less than 30% by weight ([cyclic PAS (weight) of m = 6] / [cyclic PAS mixture (weight)] × 100 (%)). Here, for example, Japanese Patent Application Laid-Open No. 10-77408 discloses a method of obtaining cyclohexa (p-phenylene sulfide) in which Ar in the cyclic PAS is a paraphenylene sulfide unit and the repeating number m is 6. This cyclic PAS with m = 6 is said to have a melting peak temperature at 348 ° C., and an extremely high processing temperature is required when processing such a cyclic PAS.

  Therefore, in the case of producing polyarylene sulfide using a polyarylene sulfide prepolymer containing cyclic polyarylene sulfide, the cyclic PAS according to the embodiment of the present invention can be used from the viewpoint that the temperature required for heating can be lowered. In particular, it is preferable that the content of the cyclic PAS of m = 6 in the formula (A) is in the above-mentioned range. Similarly, from the viewpoint that the melt processing temperature in the production of polyarylene sulfide can be lowered, in the embodiment of the present invention, a mixture of cyclic polyarylene sulfides having different repeating numbers may be used as cyclic PAS. Preferred is as described above. Here, in the cyclic PAS contained in the cyclic PAS mixture, when the total amount of cyclic PAS in which m in the formula (A) is 4 to 13 is 100% by weight, the cyclic PAS in which m is 5 to 8 It is preferable to use a cyclic PAS mixture containing 5% by weight or more of each, and it is more preferable to use a cyclic PAS mixture containing 7% by weight or more of cyclic PAS having m of 5 to 8. A cyclic PAS mixture having such a composition ratio is particularly preferred from the viewpoint of lowering the melting temperature because the melting peak temperature tends to be low and the heat of fusion tends to be small.

  Here, the content of each cyclic PAS having a different number of repetitions m with respect to the total amount of cyclic polyarylene sulfide in the cyclic PAS mixture was divided into components by high performance liquid chromatography equipped with a UV detector. The ratio of the peak area attributed to the single cyclic PAS having the desired m number to the total peak area attributed to the cyclic PAS can be obtained. In addition, the qualitative characteristics of each peak divided into components by this high performance liquid chromatography can be obtained by separating each peak by preparative liquid chromatography and performing an absorption spectrum or mass analysis in infrared spectroscopic analysis.

(6) Aryl monothiolate compound The aryl monothiolate compound in the present invention is a compound of the formula (Ar-S) xM. Here, x = 1 to 3 and M is a cation. M is derived from any component present in the reaction system of Step 1, and may be derived from the substance when a third component that does not inhibit the reaction is added. M may be a single ion or a compound ion as long as it is a cationic chemical species, and there are no particular limitations. Examples of M include, for example, lithium ions, sodium ions, potassium ions, rubidium ions, cesium ions, alkali ions, which are alkali metal ions. Examples thereof include calcium hydroxide, magnesium hydroxide, strontium hydroxide and barium hydroxide which are earth metal ions. When sodium hydrosulfide which is a preferred sulfiding agent of the present invention is used in the reaction, M is sodium. Become an ion. Examples of Ar include units represented by the following formulas (R) to (Y), etc., and p-dichlorobenzene, which is a dihalogenated aromatic compound preferably used in the present invention, is used in the reaction. , Ar has the structure of formula (R).

(In the formula, R1 and R2 are substituents selected from hydrogen, an alkyl group having 1 to 6 carbon atoms, and an alkoxy group having 1 to 6 carbon atoms, and R1 and R2 may be the same or different. )

  From the above definition, specific examples of the aryl monothiolate compound include sodium thiophenolate, sodium biphenyl-4-thiolate, sodium naphthalene-1-thiolate, sodium naphthalene-2-thiolate, sodium 4-phenoxybenzenethiolate, sodium. Examples include 4-benzophenone thiolate and sodium 4-benzylbenzene thiolate, but sodium hydrosulfide which is a sulfidizing agent preferably used in the present invention and p-dichlorobenzene which is a dihalogenated aromatic compound which is also preferably used. When used, it becomes sodium thiophenolate. In addition, since the above-mentioned aryl monothiolate compound is generally a weakly basic compound, it can be changed to an aryl thiol by acid treatment. Therefore, depending on the acidity in the reaction system and other conditions, at least a part of the aryl monothiolate compound may exist as an aryl thiol. In the present invention, the amount of the aryl monothiolate compound is the total amount of the aryl monothiolate compound and aryl thiol present in the system. As the quantification method, for example, a method of analyzing by acid chromatography or high performance liquid chromatography after acid treatment and quantifying as aryl thiol can be exemplified.

(7) Method for Producing Cyclic Polyarylene Sulfide In an embodiment of the present invention, a reaction mixture containing at least a sulfidizing agent (a), a dihalogenated aromatic compound (b) and an organic polar solvent (c) is heated to react. In the production of cyclic polyarylene sulfides, the following steps 1, 2 and 3 are included, which makes it possible to obtain high-purity cyclic polyarylene sulfides efficiently and in a short time. Is possible.
Step 1: Heating the reaction mixture having an arylene unit of 0.80 mol or more and less than 0.95 mol per mol of sulfur component in the reaction mixture, the dihalogenated aromatic compound (b) in the reaction mixture is reacted. A step of reacting until the amount of arylene units in the mixture is 10 mol% or less based on the amount of the arylene units to obtain a reaction mixture (1).
Step 2: Following step 1, the dihalogenated aromatic compound (b) is added so that the number of arylene units per mole of sulfur component in the reaction mixture (1) is 0.95 mol or more and less than 1.05 mol, A step of reacting the dihalogenated aromatic compound (b) by heating until the dihalogenated aromatic compound (b) is 10 mol% or less based on the amount of the arylene unit to obtain a reaction mixture (2).
Step 3; After step 2, after adding the dihalogenated aromatic compound (b) so that the number of arylene units per mole of the sulfur component in the reaction mixture (2) is 1.05 mol or more and 1.50 mol or less A step of further performing a reaction to obtain a reaction product containing at least a cyclic polyarylene sulfide and a linear polyarylene sulfide.

  Hereinafter, Step 1, Step 2, and Step 3 will be described in detail.

(8) Production of cyclic polyarylene sulfide; Step 1
In step 1, the reaction mixture containing the raw material components is heated and reacted to obtain a reaction mixture (1). Here, at least the sulfidizing agent and the dihalogenated aromatic compound contained in the reaction mixture react with each other, so that the production of the cyclic polyarylene sulfide as the target product proceeds. In addition, reactions such as the formation of oligomers having a thiolate group at at least one end and the formation of linear PAS proceed simultaneously.

  Here, the reaction mixture is a mixture containing at least a sulfidizing agent (a), a dihalogenated aromatic compound (b) and an organic polar solvent (c), and the cyclic polyarylene sulfide is converted by heating. It refers to the resulting mixture. In addition to the essential components, the reaction mixture includes a third component that does not significantly inhibit the formation of cyclic PAS, a third component that has the effect of accelerating the reaction, a third component that has the effect of accelerating the formation of cyclic PAS, It is also possible to add a linear PAS as will be described later. There is no particular limitation on the temperature at which the above raw materials are charged into the reactor. For example, the reaction may be performed after the raw materials are charged near room temperature. It is also possible to carry out the reaction by charging.

  The reaction mixture (1) means that the reaction mixture is heated under the conditions described in detail below, and the dihalogenated aromatic compound (b) in the reaction mixture is an amount of arylene units in the reaction mixture. Is the time when the reaction is carried out until 10 mol% or less, that is, the mixture in which step 1 is completed and transfer to step 2 becomes possible.

  In addition, an oligomer having a thiolate group at at least one end means a line having a thiolate group at at least one end generated by the reaction of the sulfidizing agent (a) and the dihalogenated aromatic compound (b). It is a polyarylene sulfide oligomer having an arylene sulfide unit and the number of repeating arylene sulfide units is usually 3 to 50, preferably 3 to 30, more preferably 3 to 25. The oligomer having a thiolate group at at least one end and the linear polyarylene sulfide have a portion that partially overlaps by definition in the present invention. Preference is given to the definition of oligomers having thiolate groups. It can be said that the oligomer having a thiolate group at at least one end can generate a cyclic PAS by intramolecular cyclization when only one end is a thiolate group. In addition, when both ends are thiolate groups, one end reacts with a dihalogenated aromatic compound, and then reacts with the other end to generate an intramolecular cyclization reaction to produce a cyclic PAS. Can be said. Therefore, an oligomer having a thiolate group at at least one end can be regarded as a precursor of cyclic polyarylene sulfide, and by producing a large amount thereof, the production rate of the final cyclic polyarylene sulfide can be increased. It seems possible.

  In Step 1, in addition to the sulfidizing agent (a) and the dihalogenated aromatic compound (b), a linear polyarylene sulfide (d) may be included as a raw material component of the reaction mixture. In this case, in addition to the sulfidizing agent and the dihalogenated aromatic compound, the linear polyarylene sulfide also reacts, and the production of the target cyclic polyarylene sulfide proceeds. Here, it is desirable that the linear polyarylene sulfide (d) to be charged as a raw material component is contained in the reaction mixture at the start of the reaction in Step 1, thereby improving the generation efficiency of the cyclic polyarylene sulfide. The reaction start time point here refers to a time point at which heating of the reaction mixture is started, and refers to a state in which substantial reaction consumption of the sulfidizing agent (a) and the dihalogenated aromatic compound (b) has not progressed. The substantial reaction consumption here includes cyclic PAS and linear PAS having a weight average molecular weight in the range of 2,500 to 500,000, which is easily produced as a by-product in the method of the embodiment of the present invention as described above. , Refers to the reaction consumption of a sufficient sulfidizing agent (a) and dihalogenated aromatic compound (b) to form. That is, the sulfidizing agent (a) and the dihalogenated aromatic compound (b) are not in a state where no reaction is consumed at all, but a very small amount of the sulfidizing agent (a) and dihalogenated which can occur without heating. The reaction consumption of the aromatic compound (b) may proceed. Therefore, the linear polyarylene sulfide (d) is mixed with the sulfidizing agent (a), the dihalogenated aromatic compound (b), and the organic polar solvent (c), which are raw material components, prior to Step 1. The order and method of mixing them are not particularly limited. Moreover, it can be said that it is economically efficient when the linear polyarylene sulfide byproduced by the method of the embodiment of the present invention is used as the linear polyarylene sulfide (d).

  Here, in a preferred embodiment of the present invention, the weight average molecular weight of all PAS components in the reaction mixture (1) at the end of Step 1 is often in the range of 1,000 or more and 10,000 or less. Is 7,000 or less, more preferably 5,000 or less, still more preferably 4,000 or less, and a preferred lower limit is 2,000 or more.

  Here, the total PAS component means a mixture of an oligomer having a thiolate group at at least one end and a cyclic PAS and a linear PAS present in the reaction system at the end of Step 1, and obtained at the end of Step 1. A component insoluble in water is separated by dispersing the reaction mixture (1) in a large excess of water, and then dried, and can be recovered as a solid content. When the weight average molecular weight of all the PAS components is within the above-described preferable range, the ratio of the oligomer having a thiolate group at at least one end suitable for cyclization tends to increase. The cyclization proceeds efficiently, and the final cyclic PAS production rate increases. Moreover, by setting it as the above preferable minimum or more, it tends to be possible to suppress the by-production of the aryl monothiolate compound in Step 1, and when Step 2 and Step 3 are performed, impurity generation derived from the aryl monothiolate compound is generated. It is possible to suppress. Although the reason for this is not clear, when the molecular weight of the oligomer having a thiolate group at at least one terminal is equal to or higher than the lower limit, the electronic instability derived from the thiolate terminal is alleviated, thereby causing an oxidative decomposition reaction. I guess it is because the progress is suppressed.

  Here, the reaction mixture used in Step 1 has an arylene unit per mole of sulfur component in the reaction mixture of 0.80 mol or more and less than 0.95 mol. If the arylene unit in the reaction mixture is less than 0.8 mole per mole of sulfur component in the reaction mixture, the by-product of the aryl monothiolate compound at the end of Step 1 is increased, and the amount of impurities in the reaction product obtained after the reaction is small. There is a tendency to increase. This must be avoided even in the case of recovering and isolating cyclic PAS because it directly leads to an increase in the impurity content contained in the isolated cyclic PAS. In addition, when the arylene unit in the reaction mixture is 0.95 mol or more per mol of the sulfur component in the reaction mixture, the amount of impurities in the reaction product obtained after the reaction is reduced, while at least becoming a precursor of the cyclic PAS. There is a tendency for the amount of oligomer having a thiolate group at one end to decrease, and the production rate of cyclic PAS tends to be insufficient. For the above reasons, in step 1, the arylene unit in the reaction mixture needs to be in the range of 0.8 mol or more and less than 0.95 mol per mol of the sulfur component in the reaction mixture. The lower limit of the arylene unit is preferably 0.82 mol, and more preferably 0.87 mol. The upper limit of the arylene unit is preferably less than 0.93 mol. In the above-described preferred range, it is possible to finally obtain cyclic PAS with particularly high purity and high production rate by performing the subsequent steps 2 and 3.

  Here, the arylene unit contained in the reaction mixture is a raw material containing an arylene unit at a stage where the reaction between the sulfidizing agent (a) charged as a raw material and the dihalogenated aromatic compound (b) does not proceed at all. In the case where is only a dihalogenated aromatic compound (b), it means an arylene unit derived from the dihalogenated aromatic compound (b) contained in the reaction mixture. In the case where the reaction has progressed or when the raw material contains linear polyarylene sulfide (d), the arylene unit derived from the dihalogenated aromatic compound contained in the reaction mixture and the arylene present in the reaction mixture The total number of arylene units derived from sulfide compounds.

  Here, in the embodiment of the present invention, the arylene sulfide compound is produced by reacting the sulfidizing agent (a) with the dihalogenated aromatic compound (b) and / or the linear polyarylene sulfide (d). . Therefore, as the reaction proceeds, an arylene sulfide unit corresponding to the amount of the dihalogenated aromatic compound consumed is newly generated. That is, when the arylene-containing component is not removed or added to the reaction mixture during the reaction, it can be said that the amount of arylene units in the reaction mixture is the same as that in the preparation stage even at the stage where the reaction has progressed.

  The amount of the arylene unit in the reaction mixture can also be determined by quantifying the amount of the arylene unit derived from the dihalogenated aromatic and the amount of the arylene sulfide compound present in the reaction system. Here, the amount of the dihalogenated aromatic compound in the reaction mixture can be determined by a gas chromatography method described later. In addition, the amount of the arylene sulfide compound in the reaction mixture is determined by determining the amount of solid content obtained by dispersing a part of the reaction mixture in a large excess of water, recovering insoluble components in water, and drying the recovered components. It can be obtained by measuring.

  Moreover, the molar amount of the sulfur component contained in the reaction mixture is synonymous with the molar amount of sulfur atoms present in the reaction mixture. For example, when 1 mole of alkali metal sulfide is present in the reaction mixture and no other component containing sulfur is present, the sulfur component contained in the reaction mixture corresponds to 1 mole. Further, when 0.5 mole of alkali metal hydrosulfide and 0.5 mole of arylene sulfide unit are present in the reaction mixture, the sulfur component contained in the reaction mixture corresponds to 1 mole.

  Therefore, when the reaction of the sulfidizing agent (a) and the dihalogenated aromatic compound (b) charged as raw materials is not progressing at all, when the raw material having sulfur atoms is only the sulfidizing agent (a), The molar amount of the sulfur component contained in the reaction mixture refers to the molar amount of the sulfur component derived from the sulfidizing agent (a). Further, when the reaction has progressed, or when the raw material contains linear polyarylene sulfide (d), the molar amount of the sulfur component contained in the reaction mixture is derived from the sulfidizing agent contained in the reaction mixture. This refers to the total molar amount of the sulfur component and the sulfur component derived from the arylene sulfide compound present in the reaction system.

  Here, as described above, in the embodiment of the present invention, the arylene sulfide compound is obtained by reacting the sulfidizing agent (a) with the dihalogenated aromatic compound (b) and / or the linear polyarylene sulfide (d). Therefore, in the progress of the reaction, an arylene sulfide unit corresponding to the amount of the sulfidizing agent consumed is newly generated. That is, if there is no removal, loss or addition of the sulfidizing agent in the reaction mixture during the reaction, it can be said that the amount of sulfur component contained in the reaction mixture is the same as in the preparation stage even at the stage where the reaction has progressed.

  Further, the amount of the sulfur component in the reaction mixture can be determined by quantifying the amount of the sulfur component derived from the sulfidizing agent and the amount of the arylene sulfide compound present in the reaction system. Here, the amount of the sulfidizing agent in the reaction mixture can be determined by an ion chromatography method described later. The method for quantifying the arylene sulfide compound in the reaction mixture is as described above.

  Conventionally, when cyclic PAS production is carried out under conditions where the arylene unit for the sulfur component in the reaction mixture is slightly excessive or insufficient, it is difficult to obtain the desired product, and cyclic polyarylene is described in detail later. There has been a problem that the separability when performing solid-liquid separation when collecting sulfide is reduced. However, the embodiment of the present invention is characterized in that Step 2 and Step 3 are performed subsequent to Step 1, so that the target product can be obtained without any problem even if the reaction is carried out in such a range, and the cyclic polyarylene sulfide is further obtained. It has been found that there is an effect that the generation rate of the is improved, and the embodiments of the present invention have been completed. Further, under the above conditions where the arylene unit for the sulfur component is insufficient, it is possible to obtain high separability in solid-liquid separation for recovering cyclic polyarylene sulfide from the reaction product described later. This is one of the characteristics of the form. In the embodiment of the present invention, setting the arylene unit per mole of the sulfur component in the reaction mixture in Step 1 to the above preferable range has an effect of further improving the yield of cyclic polyarylene sulfide. This is the preferred method.

  In step 1 of the embodiment of the present invention, as described above, linear polyarylene sulfide (d) may be included as a raw material component in the reaction mixture. In this case, the linear polyarylene sulfide (d) in the reaction mixture may be included. The content is not particularly limited as long as the raw material composition in the reaction mixture is within the above range, but is preferably 0.001 mol or more and less than 9 mol per mol of the sulfur component of the sulfidizing agent in the reaction mixture. When the amount of linear PAS used is in the above preferred range, the yield of cyclic PAS produced increases with respect to the amount of sulfiding agent and dihalogenated aromatic compound used. In other words, the amount of the sulfidizing agent and dihalogenated aromatic compound used to obtain the same amount of cyclic PAS can be saved, and the effect of being economically advantageous can be obtained, and the final cyclic PAS production rate can be obtained. Therefore, it is possible to efficiently produce a cyclic PAS.

  In step 1, the reaction mixture having the above composition is heated to carry out the reaction. The temperature in this reaction is preferably a temperature exceeding the reflux temperature of the reaction mixture under normal pressure. This desirable temperature cannot be uniquely determined because it varies depending on the kind and amount of the sulfidizing agent, dihalogenated aromatic compound and organic polar solvent used in the reaction, but is usually 120 ° C or higher, preferably 180 ° C or higher. Preferably it is 220 degreeC or more, More preferably, it can be 225 degreeC or more. Moreover, it can be 350 degrees C or less, Preferably it is 320 degrees C or less, More preferably, it is 310 degrees C or less, More preferably, it can be 300 degrees C or less. In this preferable temperature range, the substantial reaction consumption of the sulfidizing agent (a) and the dihalogenated aromatic compound (b) proceeds rapidly to form cyclic PAS and linear PAS, and the reaction proceeds in a short time. It is in. Here, the normal pressure is a pressure in the vicinity of the standard state of the atmosphere, and the standard state of the atmosphere is an atmospheric pressure condition in which the temperature is about 25 ° C. and the absolute pressure is about 101 kPa. The reflux temperature is the temperature at which the liquid component of the reaction mixture repeats boiling and condensation. In the embodiments of the present invention, it has been described above that it is desirable to heat the reaction mixture beyond the reflux temperature under normal pressure. However, as a method for bringing the reaction mixture into such a heated state, for example, the reaction mixture is heated to normal pressure. Examples thereof include a method of reacting under a pressure exceeding the pressure and a method of heating the reaction mixture in a closed container. The reaction may be either a one-step reaction performed at a constant temperature, a multi-stage reaction in which the temperature is raised stepwise, or a reaction in which the temperature is continuously changed.

  The reaction time in Step 1 depends on the type and amount of the raw material used or the reaction temperature, and thus cannot be defined unconditionally, but is preferably 0.1 hours or longer, more preferably 0.5 hours or longer. Here, as described later, when performing step 2 after step 1, it is preferable to perform step 2 after sufficiently consuming the sulfidizing agent and dihalogenated aromatic compound in the reaction mixture in step 1. By setting the above-mentioned preferable reaction time, these raw material components tend to be sufficiently consumed by reaction. On the other hand, the reaction time is not particularly limited, but the reaction proceeds sufficiently even within 40 hours, preferably within 10 hours, more preferably within 6 hours.

  In the present invention, at the end of Step 1, the content of the aryl monothiolate compound in the reaction mixture (1) is preferably less than 0.01 mol per mol of arylene units in the reaction mixture (1). In the above preferred range, the amount of low molecular weight impurities produced in the subsequent steps 2 and 3 can be suppressed, and it is possible to finally obtain a cyclic PAS with high purity. The smaller the amount of the aryl monothiolate compound at the end of the step 1, the less the generation of impurities in the subsequent step 2 and step 3, so that less than 0.005 mol per mol of the arylene unit in the reaction mixture (1). More preferred is less than 0.001 mol.

  The pressure in step 1 is not particularly limited, and the pressure varies depending on the raw materials constituting the reaction mixture, the composition thereof, the reaction temperature, etc., and thus cannot be uniquely defined. An example is 0.05 MPa or more, more preferably 0.3 MPa or more. In addition, since the pressure rise by the self-pressure of the reactant occurs at the preferable reaction temperature of the embodiment of the present invention, the lower limit of the preferable pressure at such a reaction temperature is 0.25 MPa or more, more preferably 0. 3 MPa or more can be illustrated. Moreover, as a preferable upper limit of pressure, 10 MPa or less, More preferably, 5 MPa or less can be illustrated. In such a preferable pressure range, the time required to cause the linear polyarylene sulfide, the sulfidizing agent and the dihalogenated aromatic compound to react with each other tends to be shortened. Further, in order to set the pressure at the time of heating the reaction mixture to the above preferable pressure range, the reaction mixture is reacted with an inert gas described later at an optional stage such as before starting the reaction or during the reaction, preferably before starting the reaction. It is also a preferable method to pressurize the system. Here, the gauge pressure is a relative pressure based on the atmospheric pressure, and is equivalent to a pressure difference obtained by subtracting the atmospheric pressure from the absolute pressure.

  In addition, there is no restriction | limiting in particular in the method of performing reaction, However, It is preferable to carry out on stirring conditions.

  Further, as the sulfidizing agent (a), the dihalogenated aromatic compound (b), the organic polar solvent (c), and the linear polyarylene sulfide (d), those containing water can be used. However, the amount of water at the start of the reaction, that is, at the stage where the substantial reaction consumption of the sulfidizing agent (a) and the dihalogenated aromatic compound (b) charged as a reaction mixture has not progressed is the sulfur component in the reaction mixture. The amount is preferably 0.2 mol or more, more preferably 0.5 mol or more, and further preferably 0.6 mol or more per mol. The water content is preferably 20.0 mol or less, more preferably 10.0 mol or less, and more preferably 8.0 mol or less per mol of sulfur component in the reaction mixture. preferable. When the linear polyarylene sulfide forming the reaction mixture, the sulfidizing agent, the organic polar solvent, the dihalogenated aromatic compound, and other components contain water, and the amount of water in the reaction mixture exceeds the above range, Before starting the reaction or in the middle of the reaction, it is possible to reduce the amount of water in the reaction system, and to keep the amount of water within the above range, which tends to allow the reaction to proceed efficiently in a short time. is there. In addition, when the water content of the reaction mixture is less than the above preferable range, it is also a preferable method to add water so that the water content becomes the above water content.

  When the amount of water in the reaction system is within the above preferred range (0.2 to 20.0 moles per mole of sulfur component in the reaction mixture), the raw material, linear polyarylene sulfide, sulfidizing agent, and dihalogenated aromatic The reaction efficiency of the compound tends to increase, and the cyclic polyarylene sulfide tends to be obtained efficiently in a short time. In addition, the high reaction efficiency of the raw material has the effect of relatively suppressing side reactions that proceed competitively with the cyclic polyarylene sulfide formation reaction that is the object of the embodiment of the present invention, that is, the impurity formation reaction. It can be estimated that the cyclic polyarylene sulfide having a low impurity ratio is obtained by carrying out the reaction with a preferable amount of water.

In step 1 of the present invention, it is necessary to react the dihalogenated aromatic compound (b) until it is 10 mol% or less based on the arylene unit in the reaction mixture, in other words, the dihalogenation in step 1 It is necessary to proceed the reaction until the residual reaction rate of the aromatic compound (b) becomes 10% or less. The residual amount of the dihalogenated aromatic compound in step 1 can be usually obtained by gas chromatography, and the dihalogenated aromatic compound (b) based on the arylene unit is determined according to the following formula based on the result. ) To calculate the residual reaction rate.
Remaining reaction rate (%) of dihalogenated aromatic compound (b) in step 1 = remaining amount of dihalogenated aromatic compound (b) at the end of step 1 (mole) ÷ amount of arylene units at the end of step 1 (mole) ) × 100

  If the residual reaction rate of the dihalogenated aromatic compound (b) in step 1 is shifted to step 2 in a state where the reaction residual rate is greater than 10%, the final cyclic PAS purity and production rate tend to be insufficient. Furthermore, in order to obtain cyclic PAS with higher purity and higher production rate, it is preferable to carry out the reaction in Step 1 until the residual reaction rate of the dihalogenated aromatic compound (b) is 7% or less. Since the amount of impurities derived from unreacted raw materials is reduced by moving to Step 2 after performing such a preferred reaction, the purity of the obtained cyclic PAS tends to be improved.

(9) Production of cyclic polyarylene sulfide; Step 2
In step 2, after step 1, dihalogenated aromatic compound (b) was added so that the arylene unit per mole of sulfur component in reaction mixture (1) was 0.95 mol or more and less than 1.05 mol. The dihalogenated aromatic compound (b) is reacted by heating until it is 10 mol% or less based on the amount of the arylene unit to obtain a reaction mixture (2). In this step, a reaction in which cyclic PAS is produced with high selectivity by the reaction of an oligomer having a thiolate group at at least one end and a dihalogenated aromatic compound produced in Step 1, The growth reaction progresses.

  The reaction mixture (2) is the reaction mixture (1) heated under the conditions described in detail below, and the dihalogenated aromatic compound (b) is 10 mol% or less based on the amount of the arylene unit. It means the mixture at the time when the reaction is completed, that is, when the step 2 is completed and the process can be shifted to the step 3.

  In step 2 of the present invention, it is necessary to add the dihalogenated aromatic compound (b) so that the arylene unit is in the range of 0.95 mol or more and less than 1.05 mol per mol of the sulfur component in the reaction mixture (1). There is. In the above range, the oligomer having a thiolate group at at least one end can suppress the progress of a side reaction that reacts with a dihalogenated aromatic compound to become an impurity in which both ends are blocked. It is possible to obtain a PAS. Here, as a preferable range of the arylene unit, 0.97 mol or more per 1 mol of the sulfur component can be preferably exemplified as a lower limit. On the other hand, the upper limit is preferably 1.03 mol or less per mol of sulfur component. In the above-described preferred range, it is possible to finally obtain cyclic PAS with particularly high purity and high production rate by performing the subsequent step 3. If the arylene unit is less than 0.95 mol per mol of the sulfur component, it is necessary to add a large amount of dihalogenated aromatic compound when the step 3 is subsequently performed. There is a tendency that the group compound concentration increases rapidly, the cyclization selectivity of the oligomer having a thiolate group at at least one end decreases, and the amount of impurities increases. In addition, when the arylene unit is 1.05 mol or more per 1 mol of sulfur component, the concentration of the dihalogenated aromatic compound in the system rapidly increases by adding many dihalogenated aromatic compounds at one time. The cyclization selectivity of the oligomer having a thiolate group at one end tends to decrease and the amount of impurities increases. For the above reasons, in step 2, the arylene unit needs to be in the range of 0.95 mol or more and less than 1.05 mol per mol of the sulfur component in the reaction mixture (1).

  Here, the arylene unit in step 2 refers to the total of the arylene unit in the reaction mixture (1) in step 1 and the arylene unit derived from the dihalogenated aromatic compound (b) added in step 2.

  On the other hand, the sulfur component in step 2 is the same as the sulfur component in step 1 as long as no sulfur component is added or volatilized.

  As a specific method for adding the dihalogenated aromatic compound (b) into the reaction system, a method of introducing a predetermined amount of the dihalogenated aromatic compound into the reaction system through an addition pot, or dihalogenation in a molten state Examples thereof include a method in which a dihalogenated aromatic compound made into a solution using an aromatic compound or an organic polar solvent is pressed into the reaction system by a pump.

  The temperature at which the reaction in step 2 is performed is preferably a temperature exceeding the reflux temperature under normal pressure, as in step 1. This desirable temperature cannot be uniquely determined because it varies depending on the kind and amount of the sulfidizing agent, dihalogenated aromatic compound and organic polar solvent used in the reaction, but the lower limit is usually 120 ° C. or higher, preferably 180 ° C. As mentioned above, a range of 220 ° C. or higher, more preferably 225 ° C. or higher, and even more preferably 250 ° C. or higher can be exemplified. Moreover, as an upper limit, 350 degrees C or less normally, Preferably it is 320 degrees C or less, More preferably, it is 310 degrees C or less, More preferably, the range of 300 degrees C or less can be illustrated. In the above preferred temperature range, the reaction tends to proceed in a short time.

  Moreover, it is more preferable to perform the heating in the step 2 at a temperature higher than the heating temperature in the step 1. By doing so, the consumption reaction of the dihalogenated aromatic compound is promoted, and the cyclization efficiency of the oligomer having a thiolate group at at least one terminal can be increased.

  The reaction time in Step 2 depends on the type and amount of the raw material used or the reaction temperature, and thus cannot be defined unconditionally, but the lower limit is usually 0.1 hour or longer, preferably 0.25 hour or longer. On the other hand, as the upper limit, the reaction proceeds sufficiently even within 20 hours, preferably within 5 hours, more preferably within 3 hours.

  Here, with respect to various conditions such as pressure and moisture content in the step 2, it is possible to adopt the preferable conditions in the step (8) in the previous item.

In Step 2 of the present invention, it is necessary to react until the dihalogenated aromatic compound (b) is 10 mol% or less based on the arylene unit. In other words, the dihalogenated aromatic compound (Step 2) It is necessary to proceed the reaction until the residual reaction rate of b) is 10% or less. In Step 1 described above, the reaction is allowed to proceed until the residual reaction rate of the dihalogenated aromatic compound (b) is 10% or less. However, since the process proceeds to Step 2, the dihalogenated aromatic compound is added. In step 2, this means that the reaction is further advanced than in step 1. The residual amount of the dihalogenated aromatic compound in step 2 can be usually obtained by gas chromatography, and the dihalogenated aromatic compound (b) based on the arylene unit is determined according to the following formula based on the result. ) To calculate the residual reaction rate.
Remaining reaction rate (%) of dihalogenated aromatic compound (b) in step 2 = remaining amount (mole) of dihalogenated aromatic compound (b) at the end of step 2 / amount of arylene units at the end of step 2 (mole) ) × 100

  If the reaction remaining rate of the dihalogenated aromatic compound (b) in Step 2 is greater than 10%, the process proceeds to Step 3 to finally fail to obtain cyclic PAS with high purity and high production rate. Furthermore, in order to obtain cyclic PAS with higher purity and higher production rate, it is preferable to carry out the reaction in Step 2 until the residual reaction rate of the dihalogenated aromatic compound (b) is 7% or less. By moving to Step 3 after performing such a preferred reaction, there is a strong tendency to suppress the formation of impurity components, and the purity of the resulting cyclic PAS tends to be improved.

(10) Production of cyclic polyarylene sulfide; Step 3
In Step 3, after adding Step 2, after adding the dihalogenated aromatic compound (b) so that the arylene unit per mole of the sulfur component in the reaction mixture (2) is 1.05 mol or more and 1.50 mol or less. Further reaction is performed to obtain a reaction product containing at least cyclic polyarylene sulfide and linear polyarylene sulfide.

  The reaction product refers to a mixture containing at least a cyclic polyarylene sulfide and a linear polyarylene sulfide obtained by heating the reaction mixture (2) under the conditions described in detail below. . For this reaction product, the cyclic polyarylene sulfide can be isolated and recovered by carrying out the method for recovering the cyclic polyarylene sulfide described later.

  The additional amount of the dihalogenated aromatic compound in Step 3 is such that the total amount of the arylene units in the reaction mixture (2) in Step 2 and the arylene units derived from the newly added dihalogenated aromatic compound is the reaction mixture (2). It is an additional amount that is in the range of 1.05 mol or more and 1.50 mol or less per mol of sulfur component. Here, the lower limit of the total amount of the arylene units after the addition of the dihalogenated aromatic compound is 1.05 mol or more, preferably 1.06 mol or more, per mol of the sulfur component in the reaction mixture (2). The upper limit is 1.50 mol or less, preferably 1.30 mol or less, more preferably 1.20 mol or less, still more preferably 1.15 mol or less, and still more preferably 1.12 mol or less. By carrying out the reaction in Step 3 with the total amount of the arylene units in such a range, the production rate of cyclic polyarylene sulfide tends to be improved, particularly when linear polyarylene sulfide is used as a raw material component. The tendency becomes remarkable. Furthermore, when recovering cyclic polyarylene sulfide described later, which was a problem in the prior art, not only the separation performance in the solid-liquid separation operation is remarkably improved, but also the purity of the recovered cyclic polyarylene sulfide is increased. Excellent effects such as extremely high can be obtained. On the other hand, when the additional amount of the dihalogenated aromatic compound is less than the above range, no obvious improvement in the production rate of the cyclic polyarylene sulfide is observed, and the solid content is recovered in order to recover the cyclic polyarylene sulfide. Separability during liquid separation is reduced. On the other hand, when the above range is exceeded, the yield of cyclic polyarylene sulfide is also improved, and high separability tends to be obtained during solid-liquid separation, but the residual unreacted dihalogenated aromatic compound remains. This increases the amount, necessitates a separate facility for recovering such residue, and complicates the operation. In addition, there is a disadvantage that the cost required for collection increases. For the above reasons, in step 3, the arylene unit in the reaction mixture (2) needs to be in the range of 1.05 mol or more and 1.5 mol or less per mol of the sulfur component in the reaction mixture (2). is there.

  Here, the arylene unit in the reaction mixture (2) in the step 3 refers to the arylene unit in the reaction mixture (2) in the step 2 and the dihalogenated aromatic compound (b ) Refers to the total of allylene units derived from.

  On the other hand, the sulfur component in the reaction mixture (2) in step 3 is the same as the sulfur component in step 2 as long as no sulfur component is added or volatilized.

  As a specific method for adding the dihalogenated aromatic compound into the reaction system, a predetermined amount of the dihalogenated aromatic compound is introduced into the reaction system through an addition pot, or a dihalogenated compound in a molten state is used. Examples thereof include a method in which a dihalogenated aromatic compound made into a solution using an aromatic compound or an organic polar solvent is pressed into the reaction system by a pump.

  Here, in the method of the embodiment of the present invention, the sulfur component derived from the sulfidizing agent can be quantified using, for example, an ion chromatography method equipped with an electrical conductivity detector or an electrochemical detector. As a specific evaluation method using ion chromatography, hydrogen peroxide solution is added to the sample to oxidize sulfide ions contained in the sample, and then analysis using an electrical conductivity detector Thus, a method of calculating the amount of sulfate ions generated by oxidation of sulfide ions can be exemplified.

  In step 3, the reaction is further carried out after the addition of the dihalogenated aromatic compound, and it is possible to adopt the preferred conditions in step 1 described in the previous section (8) for various conditions such as temperature, pressure and water content in this reaction. It is.

  Specifically, the reaction temperature in step 3 is preferably a temperature exceeding the reflux temperature of the reaction mixture (2) under normal pressure. Further, in step 3, a temperature higher than the temperature used in step 1 can be adopted, specifically 180 ° C. or higher, more preferably 220 ° C. or higher, and further preferably 225. It can be set to 260 ° C. or higher, more preferably 250 ° C. or higher. Moreover, the temperature of the process 3 can be 320 degrees C or less, More preferably, it is 310 degrees C or less, More preferably, it can be 300 degrees C or less. In this preferable temperature range, not only the reaction tends to proceed in a short time, but also when the temperature higher than that in Step 1 is adopted, the amount of impurity components also tends to be reduced.

  The reaction time in Step 3 depends on the type and amount of the raw material used or the reaction temperature, and thus cannot be specified unconditionally. However, the lower limit of the preferable reaction time can be exemplified by 0.1 hour or more, more preferably 0.25 hour or more. . On the other hand, as a preferable upper limit of the reaction time, the reaction proceeds sufficiently even within 20 hours, preferably within 5 hours, more preferably within 3 hours.

  In addition, each reaction of the process 1, the process 2, and the process 3 can employ | adopt various well-known polymerization systems and reaction systems, such as a batch type and a continuous method. Further, the atmosphere in the production is preferably a non-oxidizing atmosphere, preferably in an inert gas atmosphere such as nitrogen, helium, and argon. From the viewpoint of economy and ease of handling, a nitrogen atmosphere is preferable.

(11) Solid-liquid separation of reaction product; Step 4
In the embodiment of the present invention, a reaction product containing at least cyclic polyarylene sulfide and linear polyarylene sulfide is obtained by performing the above-described Step 1, Step 2, and Step 3. Here, usually, the organic polar solvent used in Step 1, Step 2, and Step 3 is also included in the reaction product.

  In the embodiment of the present invention, as step 4 subsequent to step 1, step 2 and step 3, the reaction product obtained above is subjected to solid-liquid separation in a temperature range below the boiling point of the organic polar solvent at normal pressure. It is preferable to carry out a step of obtaining a filtrate containing a cyclic polyarylene sulfide and an organic polar solvent. By performing this step 4 using the reaction product, it is possible to easily separate the cyclic polyarylene sulfide and the linear polyarylene sulfide in the reaction product.

  The temperature at which the reaction product is subjected to solid-liquid separation is preferably below the boiling point of the organic polar solvent at normal pressure. Although it depends on the type of the organic soluble polar medium, the specific temperature may be 10 ° C or higher, more preferably 15 ° C or higher, and further preferably 20 ° C or higher. Moreover, it can be 200 degrees C or less, 150 degrees C or less is more preferable, and 120 degrees C or less is still more preferable. Within the above range, cyclic polyarylene sulfide is highly soluble in organic polar solvents, while components other than cyclic polyarylene sulfide contained in the reaction product, especially linear polyarylene sulfide contained inevitably, are organic. Since it tends to be difficult to dissolve in a polar solvent, performing solid-liquid separation in such a temperature range is effective for obtaining a highly pure cyclic polyarylene sulfide as a filtrate component with high accuracy.

  In addition, the method for performing solid-liquid separation is not particularly limited, and pressure filtration or vacuum filtration that is filtration using a filter, centrifugation or sedimentation separation that is separation based on a specific gravity difference between a solid content and a solution, and a combination of these methods Etc. can be adopted. As a simpler method, pressure filtration using a filter or vacuum filtration can be preferably employed. The filter used for the filtration operation is not particularly limited as long as it is stable under the conditions for solid-liquid separation. For example, commonly used filter media such as a wire mesh filter, a sintered plate, a filter cloth, and filter paper can be suitably used.

  In addition, the pore size of the filter can be adjusted over a wide range depending on the viscosity, pressure, temperature, particle size of the solid component in the reaction product, and the like of the slurry subjected to the solid-liquid separation operation. In particular, depending on the particle diameter of the linear polyarylene sulfide recovered as a solid content from the reaction product in this solid-liquid separation operation, that is, the particle diameter of the solid content present in the reaction product to be subjected to solid-liquid separation. It is effective to select a filter pore diameter such as a mesh diameter or a pore diameter. The average particle size (median diameter) of the solid content in the reaction product to be subjected to solid-liquid separation can vary widely depending on the composition, temperature, concentration, etc. of the reaction product. As far as is known, the average particle size tends to be 1 to 200 μm. Therefore, a preferable average pore diameter of the filter can be exemplified by 0.1 μm or more, preferably 0.25 μm or more, and more preferably 0.5 μm or more. Moreover, 100 micrometers or less can be illustrated, 20 micrometers or less are preferable and 15 micrometers or less are more preferable. By using a filter medium having an average pore size in the above range, the linear polyarylene sulfide that permeates the filter medium tends to decrease, and a cyclic polyarylene sulfide having a high purity tends to be easily obtained.

  In addition, there is no particular limitation on the atmosphere when performing solid-liquid separation, but cyclic polyarylene sulfide, organic polar solvent, and linear PAS are oxidatively deteriorated depending on conditions such as time and temperature at the time of contact, It is preferably performed in a non-oxidizing atmosphere. Note that the non-oxidizing atmosphere is an atmosphere having a gas phase oxygen concentration of 5% by volume or less, preferably 2% by volume or less, and more preferably substantially free of oxygen, that is, an inert gas such as nitrogen, helium, or argon. Refers to the atmosphere. Among these, it is particularly preferable to carry out in a nitrogen atmosphere from the viewpoint of economy and ease of handling.

  Examples of the filter used for solid-liquid separation include, but are not limited to, a sieve, a vibrating screen, a centrifuge, a sedimentation separator, a pressure filter, a suction filter, and the like. In addition, from the viewpoint of performing in a non-oxidizing atmosphere which is a preferable atmosphere for solid-liquid separation as described above, it is possible to select a filter having a mechanism that can easily maintain a non-oxidizing atmosphere during solid-liquid separation operation. preferable. For example, a filter capable of performing a filtration operation after sealing the inside of the filter after being replaced with an inert gas, or a filter having a mechanism capable of performing a filtration operation while flowing an inert gas can be used. . Among the filters exemplified above, a centrifugal separator, a sedimentation separator, and a pressure filter can be said to be preferable because such functions can be easily added, and the mechanism is particularly simple. A pressure filter is more preferable from the viewpoint of excellent economic efficiency.

  There is no restriction on the pressure when performing solid-liquid separation, but in order to perform solid-liquid separation in a shorter time, it is also possible to perform solid-liquid separation under pressure using the pressure filter exemplified above Specifically, it can be exemplified as a preferable pressure range of 2.0 MPa or less in gauge pressure, more preferably 1.0 MPa or less, still more preferably 0.8 MPa or less, and even more preferably 0.5 MPa or less. . In general, as the pressure increases, it is necessary to increase the pressure resistance of the equipment that performs solid-liquid separation, and such equipment must have a high degree of sealing performance at each part constituting it, and inevitably equipment. Expenses will increase. Generally available solid-liquid separators can be used in the above preferred pressure range.

In addition, by performing Step 1, Step 2, and Step 3 which are features in the method for producing the cyclic polyarylene sulfide of the embodiment of the present invention, an extremely efficient solid-liquid is obtained when the resulting reaction product is subjected to solid-liquid separation. Separation is possible and an excellent effect of solid-liquid separation is also a significant feature of the embodiment of the present invention. Here, the solid-liquid separation property can be evaluated by the time required for solid-liquid separation when a certain amount of reaction product is solid-liquid separated. As a specific evaluation method, for example, a filter medium (filter) having a predetermined standard (pore diameter, material) and a predetermined area is installed in a pressure filtration device that can be sealed, and a predetermined amount of reaction product is charged therein. By measuring the time required to obtain a predetermined amount of filtrate under certain conditions (temperature, pressure, etc.), it is possible to make a comparative evaluation at a filtration rate in units of weight / (area / time). . More specifically, when a reaction product is filtered under conditions of 100 ° C. and 0.1 MPa using a PTFE membrane filter having an average pore diameter of 10 μm, the time required to obtain a predetermined amount of filtrate is measured. Evaluation is possible. The reaction product obtained by the conventional method for producing cyclic polyarylene sulfide has the problem that in such solid-liquid separation evaluation, the filterability and filtration speed are extremely poor. This is because Step 1, Step 2, and Step 3, which are essential steps in the embodiment, are not employed. Here, in the embodiment of the present invention, as the filtration rate, an extremely high value such as 50 kg / (m ² · hr) or more tends to be obtained, and the various kinds of those described above in the steps 1 and 2 and 3 of producing the cyclic polyarylene sulfide. By selecting a preferable numerical range in the conditions, it is possible to achieve a very high value of 100 kg / (m ² · hr) or higher and a remarkably high filtration rate reaching 150 kg / (m ² · hr).

  In addition, prior to solid-liquid separation of the reaction product, an additional operation of distilling off part of the organic polar solvent contained in the reaction product to reduce the amount of the organic polar solvent in the reaction product is performed. Is also possible. As a result, the amount of the reaction product to be subjected to the solid-liquid separation operation is reduced, so that the time required for the solid-liquid separation operation tends to be shortened.

  As a method for distilling off the organic polar solvent, any method is not particularly limited as long as the organic polar solvent is separated from the reaction product and the amount of the organic polar solvent contained in the reaction product can be reduced. Preferable methods include a method of distilling the organic polar solvent under reduced pressure or increased pressure, a method of removing the solvent by flash transfer, etc., and a method of distilling the organic polar solvent under reduced pressure or increased pressure is particularly preferable. Further, when distilling the organic polar solvent under reduced pressure or under pressure, an inert gas such as nitrogen, helium, or argon may be used as a carrier gas.

  The temperature at which the organic polar solvent is distilled off varies depending on the type of the organic polar solvent and the composition of the reaction product, and cannot be uniquely determined, but is preferably 180 ° C. or higher, preferably 200 ° C. or higher. More preferred. Moreover, 300 degrees C or less is preferable, 280 degrees C or less is more preferable, and 250 degrees C or less is further more preferable.

  According to the solid-liquid separation here, most of the cyclic polyarylene sulfide contained in the reaction product can be separated as a filtrate component, preferably 80% or more, more preferably 90% or more, and still more preferably 95. % Or more can be recovered as a filtrate component. In addition, when a part of the cyclic polyarylene sulfide remains in the linear polyarylene sulfide separated as a solid content by solid-liquid separation, it can be washed with a fresh organic polar solvent for the solid content. It is also possible to reduce the residual amount of cyclic polyarylene sulfide in the solid content. The solvent used here may be any solvent that can dissolve the cyclic polyarylene sulfide, and it is preferable to use the same solvent as the organic polar solvent used in Step 1, Step 2, and Step 3 described above.

(12) Separation of cyclic polyarylene sulfide In the embodiment of the present invention, the cyclic polyarylene sulfide can be recovered by separating the cyclic polyarylene sulfide from the filtrate component obtained by the solid-liquid separation. Is possible. There is no particular limitation on the recovery method. For example, if necessary, after removing a part or most of the organic polar solvent in the filtrate by an operation such as distillation, the solubility in the cyclic polyarylene sulfide is low and the organic polar solvent is used. A method of recovering cyclic polyarylene sulfide as a solid by bringing a solvent having a miscible property and a filtrate into contact with each other under heating as necessary can be exemplified. The solvent having such characteristics is generally a relatively polar solvent, and the preferred solvent differs depending on the organic polar solvent in the filtrate and the type of by-product contained in the filtrate. Examples thereof include alcohols typified by methanol, ethanol, propanol, isopropanol, butanol, and hexanol, ketones typified by acetone, and acetates typified by ethyl acetate and butyl acetate. From the viewpoints of availability and economy, water, methanol and acetone are preferable, and water is particularly preferable. In the above recovery operation, it is preferable to separate and recover 50% by weight or more of the cyclic polyarylene sulfide contained in the filtrate as a solid content by adding water to the filtrate.

  Here, as the weight fraction of the cyclic polyarylene sulfide in the filtrate is generally higher, the yield of the cyclic polyarylene sulfide obtained after the recovery operation increases and the cyclic polyarylene sulfide can be efficiently recovered. From this viewpoint, the content of cyclic polyarylene sulfide in the filtrate is preferably 0.5% by weight or more, more preferably 1% by weight or more, still more preferably 2% by weight or more, and even more preferably 5% by weight or more. On the other hand, the upper limit of the content of cyclic polyarylene sulfide in the filtrate is not particularly limited, but if the content is too high, insoluble components tend to be generated, which may cause inconvenience in the recovery operation. The inconvenience in this recovery operation is, for example, that the properties of the filtrate (sometimes in the form of a slurry containing solids) before the operation of adding water, which is a preferable operation, becomes uneven, and the local composition differs. The purity of the product is reduced. In addition, since the tendency for such inconvenience depends on the characteristics of the organic polar solvent used and the conditions at the time of preparing the reaction mixture, the upper limit of the content of cyclic polyarylene sulfide in the filtrate cannot be determined. % Or less, preferably 15% by weight or less, more preferably 10% by weight or less.

  In addition, the filtrate can be heated in order to avoid the inconvenience in the recovery operation as described above and to increase the content of cyclic polyarylene sulfide in the filtrate. Since this heating temperature differs depending on the characteristics of the organic polar solvent used, it cannot be uniquely determined, but is preferably 50 ° C. or higher, more preferably 70 ° C. or higher, and further preferably 90 ° C. or higher. On the other hand, the upper limit temperature of the heating temperature is preferably not higher than the boiling point at normal pressure of the organic polar solvent to be used. Within such a temperature range, the cyclic polyarylene sulfide content in the filtrate tends to be stable while maintaining a high content, which is preferable. In preparing this mixture, it is possible to perform operations such as stirring and shaking, which is desirable from the viewpoint of maintaining a more uniform state of the filtrate.

  In this recovery method, it is preferable to add and recover the cyclic polyarylene sulfide dissolved in the organic polar solvent as a solid by adding water to the filtrate. Here, there is no particular limitation on the method of adding water to the filtrate, but an addition method in which a coarse solid content is generated by adding water should be avoided. Preferably, water is added dropwise while stirring the filtrate. Is preferred. There is no limit to the temperature at which water is added, but the lower the temperature, the greater the tendency for coarse solids to form when water is added, thus avoiding such operational inconveniences and maintaining the uniformity of the mixture. From a viewpoint, 50 degreeC or more is preferable, 70 degreeC or more is more preferable, and 90 degreeC or more is further more preferable. On the other hand, the upper limit temperature for adding water is preferably not more than the boiling point at normal pressure of the organic polar solvent to be used. By performing the operation of adding water in such a preferable temperature range, the recovery operation tends to be performed by a simpler method from the viewpoint of operation and from the viewpoint of equipment.

  Further, the method of recovering cyclic PAS by adding water to the filtrate containing cyclic PAS exemplified above is compared with the reprecipitation method conventionally employed as a method for recovering cyclic PAS from the filtrate containing cyclic PAS. Therefore, the cyclic PAS can be efficiently recovered even with the use of a small amount of solvent, so that the weight of water added to the filtrate containing the cyclic PAS and the organic solvent can be greatly reduced. Specifically, the weight of water added to the filtrate can be 50% by weight or less in terms of the moisture content based on the total amount of the organic polar solvent and water after adding water. It is also possible to set a condition of 35% by weight or less under more preferable conditions. On the other hand, the lower limit of the weight of water to be added is not particularly limited, but in order to more efficiently recover cyclic PAS as a solid content, it is preferably 5% by weight or more and more preferably 10% by weight or more. In the preferable method of the embodiment of the present invention, it is possible to recover 50% by weight or more of the cyclic PAS contained in the filtrate as a solid content. There is a tendency that 80% by weight or more of cyclic PAS can be recovered as a solid content, more preferably 90% by weight or more, still more preferably 95% or more, and even more preferably 98% by weight or more can be recovered. is there.

  Here, the amount of water in the filtrate is the total amount of water contained in the reaction product before solid-liquid separation and the amount of water added to the filtrate, and the amount of water added to the filtrate. It is necessary to determine the amount of water in consideration of the amount of water contained in the reaction product.

  In the filtrate mixture containing the cyclic PAS, the organic polar solvent and water obtained by carrying out the above operations, 50% by weight or more of the cyclic PAS contained in the filtrate is present as a solid content. It becomes a trend. Therefore, cyclic PAS can be recovered as a solid using a known solid-liquid separation method. Examples of the solid-liquid separation method include separation by filtration, centrifugation, and decantation. Here, in order to efficiently recover cyclic PAS, it is preferable to perform solid-liquid separation after the filtrate mixture is in a state of less than 50 ° C., more preferably 40 ° C. or less, and further preferably 30 ° C. or less. Is preferred. It should be noted that the recovery of the cyclic PAS after such a preferable temperature is not only effective in recovering the cyclic PAS, but also the viewpoint that the cyclic PAS can be recovered with simpler equipment. However, this is a preferable condition. There is no particular lower limit to the temperature of the filtrate mixture, but it is desirable to avoid conditions that cause the viscosity of the filtrate mixture to become too high due to a decrease in temperature, or conditions that cause solidification, and are generally around normal temperature. It is most desirable to do.

  By performing such solid-liquid separation, 50% by weight or more of the cyclic PAS present in the filtrate mixture tends to be isolated and recovered as a solid content. When the solid cyclic PAS thus separated contains the liquid component (mother liquor) in the filtrate mixture, the mother liquor can be reduced by washing the solid cyclic PAS with various solvents. Is also possible. Here, as various solvents used for washing solid-liquid cyclic PAS, solvents having low solubility in cyclic PAS are desirable. For example, water, alcohols typified by methanol, ethanol, propanol, isopropanol, butanol, and hexanol are used. Examples thereof include ketones typified by acetone, and acetates typified by ethyl acetate and butyl acetate. From the viewpoints of availability and economy, water, methanol and acetone are preferable, and water is particularly preferable. By additionally performing cleaning using such a solvent, not only can the amount of mother liquor contained in solid cyclic PAS be reduced, but also the effect that impurities soluble in the solvent contained in cyclic PAS can be reduced. There is also. As this cleaning method, a method of adding a solvent to the separation filter on which the solid cake is deposited and solid-liquid separation, a method of adding a solvent to the solid cake and stirring to make a slurry, and then a solid-liquid separation again, etc. Can be illustrated. Further, for example, a general drying process may be performed on a cyclic PAS in a wet state containing a liquid component, for example, containing the above-mentioned mother liquor or containing a solvent component used for a washing operation. Thereby, it is also possible to remove the liquid component and obtain a cyclic PAS in a dry state.

  In addition, it is preferable to perform the atmosphere at the time of performing collection | recovery operation of cyclic PAS in a non-oxidizing atmosphere. This not only can suppress the occurrence of undesirable side reactions such as crosslinking reaction, decomposition reaction, oxidation reaction, etc. of cyclic PAS when recovering cyclic PAS, No side reactions tend to be suppressed. Note that the non-oxidizing atmosphere is an atmosphere in which the oxygen concentration in the gas phase in contact with various components to be recovered is 5% by volume or less, preferably 2% by volume or less, more preferably substantially free of oxygen, It refers to an inert gas atmosphere such as nitrogen, helium, or argon. Among these, a nitrogen atmosphere is particularly preferable from the viewpoints of economy and ease of handling.

(13) Characteristics of the cyclic PAS recovered in the embodiment of the present invention The cyclic PAS thus obtained usually has a cyclic PAS of 50% by weight or more, preferably 70% by weight or more, more preferably 80% by weight. It has a high purity, and has high utility value even industrially having characteristics different from generally obtained linear PAS. Moreover, in the cyclic PAS obtained by the production method of the embodiment of the present invention, m in the formula (Q) is not single, and the formula (Q) having m different from m = 4 to 50 is easily obtained. It has the characteristics. Here, a preferable range of m is 4 to 30, more preferably 4 to 25. When m is within this range, as described later, when cyclic PAS is used in various resins, the PAS tends to be melted at a lower temperature. When a prepolymer containing PAS is converted to a high degree of polymerization, the polymerization reaction tends to proceed, and a high molecular weight product tends to be easily obtained. The reason for this is not clear at this time, but it is assumed that cyclic PAS in this range has a large bond distortion due to the fact that the molecule is cyclic, and that a ring-opening reaction easily occurs during polymerization. Also, since cyclic PAS with a single m is obtained as a single crystal, it has a very high melting temperature. However, in embodiments of the present invention, it is easy to obtain a mixture having different m in cyclic PAS. It is characterized by a low melting temperature of PAS. This expresses an excellent feature that the heating temperature when the cyclic PAS is melted and used can be lowered.

  Further, the cyclic PAS according to the embodiment of the present invention is excellent in that the content of a low molecular weight compound (hereinafter sometimes referred to as a low molecular weight PAS) having a different structure from that of the cyclic PAS comprising an arylene sulfide unit is extremely small. It has the characteristics. Such low molecular weight compounds are different in characteristics from cyclic PAS and linear PAS having sufficient molecular weight, and are inferior in heat resistance, for example, and thus increase the outgas when heated during molding processing. In addition, the low molecular weight compound has an adverse effect such as acting as a component that inhibits the high molecular weight when the cyclic PAS is used as a prepolymer of a high molecular weight substance described later. The method for producing a cyclic PAS according to an embodiment of the present invention is characterized in that it is possible to obtain a high-purity PAS in which such low molecular PAS is remarkably reduced by including the steps 1 and 2. Also have.

  Here, the low molecular weight PAS content contained as an impurity in the cyclic PAS can be calculated from the peak area obtained by component separation by high performance liquid chromatography equipped with a UV detector and an ODS column. By such a method, the weight fraction of the low molecular weight PAS component in the isolated solid of cyclic PAS containing the low molecular weight PAS component can be calculated. Also, based on the peak area detected by high performance liquid chromatography analysis, the peak attributed to the low molecular weight PAS when the total detected peak area is used as the parameter (corresponds to the peak other than the peak attributed to cyclic PAS) It is also possible to calculate the content ratio of the low molecular weight PAS component as a ratio of the total area of (1), that is, the peak area ratio.

  In the embodiment of the present invention, as described above, a high-purity cyclic PAS having a very low content of low molecular weight PAS contained in the cyclic PAS can be obtained. Therefore, it is possible to obtain an extremely high-purity cyclic PAS having a weight fraction of low molecular weight PAS in the evaluation method of 7% by weight or less, preferably 5% by weight or less, more preferably 3% by weight or less. Further, when the ratio of the peak area of the low molecular weight compound is evaluated, if the ratio of the peak derived from other than the cyclic polyphenylene sulfide is defined as the impurity ratio, the impurity ratio is 9% by weight according to the preferred production method of the embodiment of the present invention. In the following, it is possible to obtain a cyclic PAS of preferably 6% by weight or less, more preferably 4% by weight or less.

(14) Resin composition blended with cyclic PAS recovered in the embodiment of the present invention The cyclic PAS obtained in the embodiment of the present invention can be blended with various resins and used. A resin composition blended with cyclic PAS has a strong tendency to exhibit excellent fluidity during melt processing, and tends to have excellent residence stability. Such improved properties, particularly fluidity, express the characteristics of excellent melt processability even when the heating temperature during melt processing of the resin composition is low, so that extrusion molding of injection molded products, fibers, films, etc. This is a great merit in that it improves the melt processability when processed into a product. The reason why such improvement in properties is manifested when cyclic PAS is blended is not clear, but because of the specificity of cyclic PAS structure, that is, the cyclic structure, it is compact compared to ordinary linear compounds. It is assumed that the entanglement with various resins that are matrixes tends to be reduced, that it acts as a plasticizer for various resins, and that the entanglement between matrix resins is also suppressed. .

  Although there is no restriction | limiting in particular in the compounding quantity at the time of mix | blending cyclic PAS with various resin, The cyclic PAS of embodiment of this invention is 0.1 weight part or more with respect to 100 weight part of various resin, Preferably it is 0.8. By blending 5 parts by weight or more, it is possible to obtain a remarkable improvement in characteristics. Moreover, it is possible to obtain a remarkable improvement in characteristics by blending 50 parts by weight or less, preferably 20 parts by weight or less, more preferably 10 parts by weight or less.

  Moreover, it is also possible to mix | blend a fibrous and / or non-fibrous filler with the said resin composition as needed. The blending amount can be 0.5 parts by weight or more, preferably 1 part by weight or more with respect to 100 parts by weight of the various resins. Moreover, it can be 400 weight part or less, Preferably it is 300 weight part or less, More preferably, it is 200 weight part or less, More preferably, it is 100 weight part or less. By setting the blending amount of the filler within such a range, the mechanical strength tends to be improved while maintaining excellent fluidity in the resin composition. As the kind of filler, any filler such as fibrous, plate-like, powdery, and granular can be used. Specific examples of these fillers include layered silicates such as glass fiber, talc, wollastonite, montmorillonite, and synthetic mica, and glass fiber is particularly preferable. The type of glass fiber is not particularly limited as long as it is generally used for reinforcing a resin, and can be selected from, for example, a long fiber type, a short fiber type chopped strand, a milled fiber, or the like. Moreover, said filler can also be used in combination of 2 or more types. In addition, said filler used for embodiment of this invention processes the surface with a well-known coupling agent (For example, a silane coupling agent, a titanate coupling agent, etc.) and other surface treatment agents. It can also be used. Further, the glass fiber may be coated or bundled with a thermoplastic resin such as an ethylene / vinyl acetate copolymer or a thermosetting resin such as an epoxy resin.

  Moreover, in order to maintain the thermal stability of the resin composition, it is also possible to contain one or more heat-resistant agents selected from phenolic and phosphorus compounds. The blending amount of the heat-resistant agent is preferably 0.01 parts by weight or more, more preferably 0.02 parts by weight or more with respect to 100 parts by weight of the various resins, from the viewpoint of the heat resistance improvement effect. From the viewpoint of gas components generated during molding, it is preferably 5 parts by weight or less, particularly 1 part by weight or less with respect to 100 parts by weight of the various resins. In addition, it is particularly preferable to use a phenolic compound and a phosphorus compound in combination because of their large heat resistance, heat stability, and fluidity retention effect.

  Further, the resin composition includes the following compounds, that is, coupling agents such as organic titanate compounds and organic borane compounds, polyalkylene oxide oligomer compounds, thioether compounds, ester compounds, and organic phosphorus compounds. Plasticizers such as base compounds, crystal nucleating agents such as talc, kaolin, organophosphorus compounds, and polyether ether ketone, metal soaps such as montanic acid waxes, lithium stearate, and aluminum stearate, ethylenediamine, stearin Release agents such as acid and sebacic acid heavy compound and silicone compounds, anti-coloring agents such as hypophosphite, other lubricants, anti-ultraviolet agents, coloring agents, flame retardants, foaming agents, etc. The usual additives can be blended. All of the above compounds tend to exhibit their effects effectively when added in an amount of less than 20 parts by weight, preferably 10 parts by weight or less, more preferably 1 part by weight or less, based on 100 parts by weight of the various resins.

  The method for producing the resin composition comprising the cyclic PAS as described above is not particularly limited. For example, the cyclic PAS, various resins, and other fillers and various additives as necessary may be added in advance. After blending, a method of melting and kneading with a generally known melt mixer such as a single-screw or twin-screw extruder, Banbury mixer, kneader, mixing roll or the like at a melting point of various resins and cyclic PAS, or a resin composition material A method of removing the solvent after mixing in the medium is used. Here, when cyclic PAS is used as a simple substance of cyclic PAS, that is, when m of the above formula (Q) is a single one, or when a mixture of different m is used having a high crystallinity and a high melting point. , A method in which cyclic PAS is previously dissolved in a solvent in which cyclic PAS is dissolved and supplied to a melt mixer, and the solvent is removed during melt-kneading, and cyclic PAS is once dissolved above its melting point and then rapidly cooled. In this method, the crystallization is suppressed and the amorphous material is supplied to the melt mixer, or the premelter is set to a melting point or higher of the cyclic PAS, and only the cyclic PAS is melted in the premelter and melt-mixed as a melt. A method of supplying to the machine can be adopted.

  Here, there are no particular restrictions on the various resins that contain cyclic PAS, which can be applied to crystalline resins and amorphous resins, and can also be applied to thermoplastic resins and thermosetting resins. .

  Specific examples of the crystalline resin include polyolefin resins such as polyethylene resin, polypropylene resin, and syndiotactic polystyrene, polyvinyl alcohol resin, polyvinylidene chloride resin, polyester resin, polyamide resin, polyacetal resin, polyphenylene sulfide. Resins, polyetheretherketone resins, polyetherketone resins, polyketone resins, polyimide resins and copolymers thereof may be used, and one or more of them may be used in combination. Of these, polyphenylene sulfide resins, polyamide resins, and polyester resins are preferred in terms of heat resistance, moldability, fluidity, and mechanical properties. Moreover, a polyester resin is preferable from the viewpoint of transparency of the obtained molded product. When a crystalline resin is used as the various resins, there is a tendency to improve the crystallization characteristics in addition to the improvement in fluidity described above. In addition, it is particularly preferable to use polyphenylene sulfide resin as various resins. In this case, it is said that the improvement of the crystallinity and the effect of these effects are significantly suppressed in the injection molding as well as the fluidity. Features tend to develop easily.

  The amorphous resin is not particularly limited as long as it is an amorphous resin that can be melt-molded. However, in terms of heat resistance, the glass transition temperature is preferably 50 ° C. or higher, and is 60 ° C. or higher. Is more preferably 70 ° C. or higher, and particularly preferably 80 ° C. or higher. The upper limit of the glass transition temperature is not particularly limited, but is preferably 300 ° C. or less, more preferably 280 ° C. or less from the viewpoint of moldability. In the embodiment of the present invention, the glass transition temperature of the amorphous resin is increased under the temperature rising condition of 20 ° C./min from 30 ° C. to the predicted glass transition temperature or higher in the differential calorimetry. After being warmed and held for 1 minute, it was once cooled to 0 ° C. under a temperature drop condition of 20 ° C./minute, held for 1 minute, and then observed again when measured under a temperature rise condition of 20 ° C./minute ( Tg). Specific examples of such an amorphous resin include amorphous nylon resin, polycarbonate (PC) resin, polyarylate resin, ABS resin, poly (meth) acrylate resin, poly (meth) acrylate copolymer, polysulfone resin, And at least one selected from polyethersulfone resins, and may be used alone or in combination of two or more. Among these amorphous resins, polycarbonate (PC) resin having particularly high transparency, and among ABS resins, transparent ABS resin, polyarylate resin, poly (meth) acrylate resin, poly (meth) acrylate copolymer, and polyether A sulfone resin can be preferably used. In the case of using an amorphous resin excellent in transparency as various resins, in addition to the improvement in fluidity at the time of melt processing described above, it is possible to express the feature that high transparency can be maintained. Here, when it is desired to develop high transparency in the amorphous resin composition, it is preferable to use a cyclic PAS having a different m in the formula (Q) as the cyclic PAS. When a cyclic PAS is used alone, that is, when m in the formula (Q) is single, such a cyclic PAS tends to have a high melting point. When kneading, the cyclic PAS having a different m in the formula (Q) has a melting temperature as described above. This tends to be low, which is effective in improving the uniformity during melt-kneading. Here, in the cyclic PAS obtained by the production method according to the embodiment of the present invention, m in the formula (Q) is not single, and the formula (Q) having m different from 4 to 50 is obtained. Since it has the characteristic that it is easy, it is especially advantageous when it is desired to obtain an amorphous resin composition having high transparency.

  The resin composition obtained by blending cyclic PAS with various resins obtained above can be molded by any known method such as injection molding, extrusion molding, blow molding, press molding, spinning, etc. Can be processed and used. As molded products, they can be used as injection molded products, extrusion molded products, blow molded products, films, sheets, fibers, and the like. The various molded articles thus obtained can be used for various applications such as automobile parts, electrical / electronic parts, building members, various containers, daily necessities, household goods and sanitary goods. Moreover, the said resin composition and a molded article consisting thereof can be recycled. For example, a resin composition obtained by pulverizing a resin composition and a molded product comprising the resin composition, preferably in a powder form, and then adding additives as necessary, can be used in the same manner as the resin composition described above. It can also be a molded product.

(15) Conversion of cyclic PAS to high polymerization degree Since the cyclic PAS recovered by the embodiment of the present invention has excellent characteristics as described in the above section (13), it is a PAS polymer, that is, a high polymerization degree. It is possible to use suitably as a prepolymer at the time of obtaining. Here, as the prepolymer, the cyclic PAS obtained by the cyclic PAS recovery method of the embodiment of the present invention may be used alone, or it may contain a predetermined amount of other components. However, when a component other than the cyclic PAS is included, a PAS component such as a linear PAS or a PAS having a branched structure is particularly preferable. A polyarylene sulfide prepolymer that contains at least the cyclic PAS of the embodiment of the present invention and can be converted into a high degree of polymerization by the method exemplified below is sometimes referred to as a PAS prepolymer.

  The conversion of the cyclic PAS to a high degree of polymerization may be performed under conditions where a high molecular weight product is formed from the cyclic PAS as a raw material, including, for example, the cyclic PAS produced by the cyclic PAS production method of the embodiment of the present invention. A method of heating the PAS prepolymer to convert it to a high degree of polymerization can be exemplified as a preferred method. The heating temperature is preferably a temperature at which the PAS prepolymer melts, and there is no particular limitation as long as it is such a temperature condition. If the heating temperature is lower than the melt solution temperature of the PAS prepolymer, a long time tends to be required to obtain a PAS having a high molecular weight. Although the temperature at which the PAS prepolymer melts varies depending on the composition and molecular weight of the PAS prepolymer and the environment during heating, it cannot be uniquely indicated. For example, the PAS prepolymer is a differential scanning calorimeter. It is possible to grasp the melting solution temperature by analyzing with. If the heating temperature is too high, undesirable side reactions such as cross-linking reactions and decomposition reactions between PAS prepolymers, between PASs generated by heating, and between PAS and PAS prepolymers generated by heating are likely to occur. In some cases, the characteristics of the obtained PAS may deteriorate. Therefore, it is desirable to avoid a temperature at which such an undesirable side reaction is remarkably generated. Examples of the heating temperature at which the manifestation of such undesirable side reactions can be suppressed include 180 ° C. or higher, preferably 200 ° C. or higher, and more preferably 250 ° C. or higher. Moreover, 400 degreeC or less can be illustrated as said heating temperature, Preferably it is 380 degrees C or less, More preferably, it is 360 degrees C or less. On the other hand, if there is no problem even if a certain degree of side reaction occurs, a temperature range of 250 ° C. or higher, preferably 280 ° C. or higher can be selected. Further, a temperature range of 450 ° C. or lower, preferably 420 ° C. or lower can be selected. In this case, there is an advantage that the conversion to a high molecular weight can be performed in a very short time.

  The time for performing the heating cannot be uniformly defined because it varies depending on various properties such as the content and m number of the cyclic PAS in the PAS prepolymer to be used and the molecular weight, and the conditions such as the temperature of the heating. It is preferable to set so that the undesirable side reaction does not occur as much as possible. Examples of the heating time include 0.05 hours or more, and preferably 0.1 hours or more. Moreover, 100 hours or less can be illustrated, 20 hours or less are preferable and 10 hours or less are more preferable. When the heating time is less than 0.05 hours, the conversion of the PAS prepolymer to PAS tends to be insufficient. In addition, when the heating time exceeds 100 hours, there is a tendency not only to increase the possibility of adverse effects due to undesirable side reactions on the properties of the PAS to be obtained, but also to cause economic disadvantages. There is a case.

  In addition, when the PAS prepolymer is converted to a high degree of polymerization by heating, various catalyst components that promote the conversion can be used. Examples of such catalyst components include ionic compounds and compounds having radical generating ability. Examples of the ionic compound include thiophenol sodium salt and lithium salt, and sulfur alkali metal salt. Moreover, as a compound which has radical generating ability, the compound which generate | occur | produces a sulfur radical by heating can be illustrated, for example, More specifically, the compound containing a disulfide bond can be illustrated. When various catalyst components are used, the catalyst component is usually taken into PAS, and the obtained PAS often contains the catalyst component. In particular, when an ionic compound containing an alkali metal and / or other metal component is used as a catalyst component, most of the metal component contained therein tends to remain in the obtained PAS. In addition, PAS obtained using various catalyst components tends to increase in weight loss when PAS is heated. Therefore, when a higher purity PAS is desired and / or when a PAS with less weight loss when heated is desired, it is desirable to use as little as possible, preferably not, a catalyst component. Therefore, when converting the PAS prepolymer to a high degree of polymerization using various catalyst components, the amount of alkali metal in the reaction system containing the PAS prepolymer and the catalyst component is 100 ppm or less, preferably 50 ppm or less, more preferably Is 30 ppm or less, more preferably 10 ppm or less, and the weight of sulfur atoms constituting the disulfide group is less than 1% by weight, preferably less than 0.5% by weight, based on the weight of all sulfur atoms in the reaction system. More preferably, the addition amount of the catalyst component is adjusted so as to be less than 0.3% by weight, and more preferably less than 0.1% by weight.

  Conversion of the PAS prepolymer to a high degree of polymerization by heating is usually performed in the absence of a solvent, but can also be performed in the presence of a solvent. The solvent is not particularly limited as long as it does not substantially cause undesirable side reactions such as inhibition of conversion to a high degree of polymerization by heating the PAS prepolymer and decomposition or crosslinking of the produced PAS. For example, nitrogen-containing polar solvents such as N-methyl-2-pyrrolidone, dimethylformamide, and dimethylacetamide, sulfoxide-sulfon solvents such as dimethyl sulfoxide and dimethyl sulfone, and ketone systems such as acetone, methyl ethyl ketone, diethyl ketone, and acetophenone Solvents, ether solvents such as dimethyl ether, dipropyl ether, and tetrahydrofuran; halogen solvents such as chloroform, methylene chloride, trichloroethylene, ethylene chloride, dichloroethane, tetrachloroethane, and chlorobenzene; methanol, ethanol, propanol , Butanol, pentanol, ethylene glycol, propylene glycol, phenol, cresol, and polyethylene glycol Or alcohol phenol based solvents, benzene, toluene, and the like aromatic hydrocarbon solvents such as xylene. It is also possible to use an inorganic compound such as carbon dioxide, nitrogen, or water as a solvent in a supercritical fluid state. These solvents can be used as one kind or a mixture of two or more kinds.

  The conversion of the PAS prepolymer to a high degree of polymerization by heating may be performed in a mold for producing a molded product, as well as by a method using a normal polymerization reaction apparatus, an extruder, Any apparatus equipped with a heating mechanism, such as a melt kneader, can be used without particular limitation, and known methods such as a batch method and a continuous method can be employed.

  The atmosphere during the conversion of the PAS prepolymer to a high degree of polymerization by heating is preferably a non-oxidizing atmosphere, and is also preferably performed under reduced pressure. Moreover, when it carries out under pressure reduction conditions, it is preferable to make it the pressure reduction conditions after making the atmosphere in a reaction system once non-oxidizing atmosphere. Thereby, it is in the tendency which can suppress generation | occurrence | production of undesirable side reactions, such as a crosslinking reaction and a decomposition reaction between PAS prepolymers, between PAS produced | generated by heating, and between PAS produced | generated by heating, and a PAS prepolymer. Note that the non-oxidizing atmosphere is an atmosphere in which the oxygen concentration in the gas phase in contact with the PAS component is 5% by volume or less, preferably 2% by volume or less, and more preferably contains substantially no oxygen, that is, nitrogen, helium, argon, etc. The inert gas atmosphere. Among these, a nitrogen atmosphere is particularly preferable from the viewpoints of economy and ease of handling. The reduced pressure condition means that the reaction system is lower than the atmospheric pressure, and the upper limit is preferably 50 kPa or less, more preferably 20 kPa or less, and even more preferably 10 kPa or less. An example of the lower limit is 0.1 kPa or more, and 0.2 kPa or more is more preferable. When the decompression condition exceeds the preferable upper limit, an undesirable side reaction such as a crosslinking reaction tends to occur. On the other hand, when the pressure reduction condition is less than the preferred lower limit, the cyclic polyarylene sulfide having a low molecular weight contained in the PAS prepolymer tends to be volatilized depending on the reaction temperature.

  The conversion of the PAS prepolymer to a high degree of polymerization can be performed in the presence of a fibrous material. Here, the fibrous substance is a fine thread-like substance, and an arbitrary substance having a structure elongated like a natural fiber is preferable. By converting the PAS prepolymer to a high polymerization degree in the presence of the fibrous substance, a composite material structure composed of PAS and the fibrous substance can be easily prepared. Since such a structure is reinforced by a fibrous material, it tends to have superior mechanical properties, for example, compared to the case of PAS alone.

  Here, among the various fibrous materials, it is preferable to use reinforcing fibers made of long fibers, which makes it possible to highly reinforce PAS. In general, when producing a composite material structure composed of a resin and a fibrous substance, the resin and the fibrous substance tend to become poorer due to the high viscosity when the resin is melted. In many cases, composite materials cannot be produced or expected mechanical properties do not appear. Here, wetting is the physical state of the fluid material and the solid substrate so that substantially no air or other gas is trapped between the fluid material such as a molten resin and the solid substrate such as a fibrous compound. Means there is good and maintained contact. Here, the lower the viscosity of the fluid substance, the better the wetting with the fibrous substance. The PAS prepolymer of the embodiment of the present invention has good wettability with a fibrous material because its viscosity when melted is significantly lower than that of a general thermoplastic resin, for example, PAS produced by a conventionally known method. It is easy to become. After the PAS prepolymer and the fibrous material form good wetting, the PAS prepolymer is converted into a high polymerization degree according to the method for producing a PAS of the embodiment of the present invention. A composite material structure in which (polyarylene sulfide) forms good wetting can be easily obtained.

  As mentioned above, the fibrous fiber is preferably a reinforcing fiber composed of long fibers, and the reinforcing fiber used in the embodiment of the present invention is not particularly limited. Examples thereof include fibers having good heat resistance and tensile strength used as reinforcing fibers. For example, examples of the reinforcing fiber include glass fiber, carbon fiber, graphite fiber, aramid fiber, silicon carbide fiber, alumina fiber, and boron fiber. Among these, carbon fiber and graphite fiber, which have good specific strength and specific elastic modulus and have a great contribution to weight reduction, can be exemplified as the best. As carbon fiber or graphite fiber, any kind of carbon fiber or graphite fiber can be used depending on the application, but high strength and high elongation with a tensile strength of 450 kgf / mm 2 and a tensile elongation of 1.6% or more. Carbon fiber is most suitable. In the case of using long fiber-like reinforcing fibers, the length is preferably 5 cm or more. In the range of this length, it becomes easy to sufficiently develop the strength of the reinforcing fiber as a composite material. Carbon fibers and graphite fibers may be used in combination with other reinforcing fibers. Moreover, the shape and arrangement | sequence of a reinforced fiber are not limited, For example, even if it is a single direction, a random direction, a sheet form, a mat form, a textile form, and a braid form, it can be used. In particular, for applications that require high specific strength and specific elastic modulus, an array in which reinforcing fibers are aligned in a single direction is most suitable. Arrangements are also suitable for embodiments of the present invention.

  The conversion of the PAS prepolymer to a high degree of polymerization can be performed in the presence of a filler. Examples of the filler include non-fibrous glass, non-fibrous carbon, and inorganic fillers such as calcium carbonate, titanium oxide, and alumina.

  The present invention will be specifically described below with reference to examples. These examples are illustrative and not limiting. First, a method for evaluating samples obtained by the methods for producing cyclic polyarylene sulfides of Examples and Comparative Examples will be described.

<Analysis of cyclic polyphenylene sulfide>
Qualitative quantitative analysis of the cyclic polyphenylene sulfide compound was performed using high performance liquid chromatography (HPLC). The measurement conditions for HPLC are shown below.
Apparatus: LC-10Avp series manufactured by Shimadzu Corporation Column: Mightysil RP-18 GP150-4.6 (5 μm) manufactured by Kanto Chemical Co., Inc.
Detector: Photodiode array detector (wavelength 270 nm)

  The structure of each component separated by HPLC is determined by liquid chromatography / mass spectrometry (LC-MS) and by matrix-assisted laser desorption / ionization of the fraction in preparative liquid chromatography (preparative LC). The analysis was performed by mass spectrometry (MALDI-MS), analysis by nuclear magnetic resonance spectroscopy (NMR), and infrared spectroscopy (IR measurement). Thereby, it was confirmed that cyclic polyphenylene sulfide having 4 to 15 repeating units can be qualitatively quantified by HPLC measurement under these conditions.

  The peaks detected in the HPLC analysis were classified into peaks derived from cyclic polyphenylene sulfide and peaks derived from the others. The ratio (area ratio) of the integrated value of the detected area of the peak derived from other than the cyclic polyphenylene sulfide to the integrated value of the detected area of all the detected peaks is defined as the impurity ratio, and the amount of impurities of the cyclic polyphenylene sulfide is defined as the impurity ratio. Compared.

<Analysis of dihalogenated aromatic compounds>
Quantification of the dihalogenated aromatic compound in the reaction mixture, reaction product and intermediate product during the reaction (quantification of p-dichlorobenzene) was carried out using gas chromatography under the following conditions.
Device: GC-2010 manufactured by Shimadzu Corporation
Column: DB-5 manufactured by J & W, Inc. 0.32 mm × 30 m (0.25 μm)
Carrier gas: Helium detector: Flame ionization detector (FID)

<Analysis of sodium thiophenolate>
Sodium thiophenolate is analyzed by taking a small amount of the reaction mixture (1) at the end of Step 1, treating with an acidic aqueous solution, and then quantifying it as thiophenol by gas chromatography analysis of the chloroform solution extracted with chloroform. I went there. This quantitative value is equal to the amount of the aryl monothiolate compound referred to in the present invention. The measurement conditions of gas chromatography were the same as the analysis of the dihalogenated aromatic compound.
Among the peaks detected by the gas chromatographic analysis, thiophenol was quantified based on the retention time and peak area of the sample measured separately.

<Evaluation of solid-liquid separation of reaction product>
Evaluation of the solid-liquid separability of the reaction product was performed under the following conditions.

  200 g of the obtained reaction product was collected and charged into a 300 mL flask. The reaction product was stirred with a magnetic stirrer and heated to 100 ° C. in an oil bath while nitrogen bubbling was performed on the reaction product slurry.

  A polytetrafluoroethylene (PTFE) membrane filter having a diameter of 90 mm and an average pore diameter of 10 μm is set on a filter holder KST-90-UH (effective filtration area of about 45 parallel centimeters) manufactured by ADVANTEC, The tank part was adjusted to 100 ° C. with a band heater.

The reaction product heated to 100 ° C. was charged into the tank, and after sealing the tank, the inside of the tank was pressurized to 0.1 MPa with nitrogen. Starting from the time when the filtrate begins to be discharged from the lower part of the filter holder after pressurization, the time until 50 g of the filtrate is discharged is measured, and the filtration rate based on the unit filtration area (kg / (m ² · hr )) Was calculated.

<Molecular weight measurement method>
The weight average molecular weight of all the PAS components recovered from the reaction mixture at the end of step 1 was measured under the following conditions and determined as standard polystyrene conversion.
Apparatus: SSC-7100 manufactured by Senshu Scientific
Column: Shodex UT806M × 2
Column temperature: 210 ° C
Mobile phase: 1-chloronaphthalene detector: differential refractive index detector Detector temperature: 210 ° C.

[Example 1]
<Preparation of reaction mixture>
In an autoclave equipped with a stirrer made of SUS316L, 25.7 g of a 48 wt% sodium hydrosulfide aqueous solution (0.220 mol as sodium hydrosulfide) as a sulfiding agent (a), 19.2 g of 48 wt% sodium hydroxide aqueous solution (water) 0.230 mol) as sodium oxide, 29.1 g (0.198 mol) of p-dichlorobenzene (p-DCB) as dihalogenated aromatic compound (b), and N-methyl- as organic polar solvent (c) A reaction mixture was prepared by charging 564 g (0.550 L) of 2-pyrrolidone (NMP). The amount of water contained in the raw material was 23.3 g (1.30 mol), and the amount of solvent per mol of the sulfur component in the reaction mixture (corresponding to sodium hydrosulfide charged as a sulfidizing agent) was 2.50 L. It was. Further, the sulfur component in the reaction mixture (corresponding to sodium hydrosulfide charged as a sulfidizing agent) per 1 mol of arylene unit (corresponding to p-DCB charged as a dihalogenated aromatic compound) was 0.900 mol. .

<Step 1>
The inside of the autoclave was sealed after being replaced with nitrogen gas, and the temperature was raised from room temperature to 200 ° C. over about 1 hour while stirring at 400 rpm. Next, the temperature was raised from 200 ° C. to 250 ° C. over about 0.5 hour. The pressure in the reactor at this stage was 0.77 MPa in terms of gauge pressure. Thereafter, the reaction mixture was kept at 250 ° C. for 2 hours to be reacted by heating to obtain a reaction mixture (1).

<Process 2>
An NMP solution of p-DCB (3.23 g of p-DCB was dissolved in 20.0 g of NMP) was charged into a 100 mL small tank installed at the top of the autoclave via a high pressure valve. Next, after pressurizing the inside of the small tank to about 1.5 MPa, the valve at the bottom of the tank was opened, and the p-DCB solution was charged into the autoclave. After washing the wall surface of the small tank with 8.2 g of NMP, this NMP was also charged into the autoclave. By this operation, the arylene unit per mole of the sulfur component (corresponding to the total amount of p-DCB charged as the dihalogenated aromatic compound in Step 1 and Step 2) was 1.00 mole. After the completion of this additional preparation, the internal temperature was raised to 260 ° C. over 10 minutes, and the reaction was continued by heating at 260 ° C. for 1 hour to obtain a reaction mixture (2).

<Step 3>
Following the step 2, the NMP solution of p-DCB (3.23 g of p-DCB was dissolved in 20.0 g of NMP) was charged again into a 100 mL small tank installed at the top of the autoclave through the high pressure valve. After pressurizing the inside of the small tank to about 1.5 MPa, the valve at the bottom of the tank was opened, and the p-DCB solution was charged into the autoclave. After washing the wall surface of the small tank with 8.2 g of NMP, this NMP was also charged into the autoclave. By this operation, the arylene unit per mole of the sulfur component in the reaction mixture (2) (corresponding to the total amount of p-DCB charged as the dihalogenated aromatic compound in Step 1, Step 2 and Step 3) was 1.10. It became a mole. After the completion of this additional preparation, the reaction was continued by maintaining the internal temperature of 260 ° C. and further heating for 1 hour. After the completion of step 3, the high-pressure valve installed at the top of the autoclave was gradually opened to discharge the steam mainly composed of NMP, and this steam component was aggregated in a water-cooled cooling tube to recover 522 g of liquid component. Later, the high pressure valve was closed and sealed. Thereafter, the autoclave was quenched to near room temperature, and the reaction product was recovered.

<Reaction product analysis evaluation>
A part of the obtained reaction product was dispersed in a large excess of water to recover components insoluble in water, and then dried to obtain a solid content. As a result of structural analysis by infrared spectroscopic analysis, it was confirmed that the solid content was a compound composed of phenylene sulfide units.

As a result of analyzing the obtained reaction product by high performance liquid chromatography, it was found that the production rate of cyclic polyphenylene sulfide was 21.1% when all the sulfidizing agents in the reaction mixture were converted to cyclic polyphenylene sulfide. It was. The ratio of the peak area derived from other than cyclic PAS to the total peak area detected by high performance liquid chromatography of the reaction solution, that is, the impurity ratio was 2.4%. Moreover, when the solid-liquid separability was evaluated about the obtained reaction liquid, it was 315 kg / (m < ² > * hr).

  Further, as a result of performing gas chromatography on the reaction mixture (1) recovered after completion of the operation in the stage up to Step 1, the residual amount of the dihalogenated aromatic compound at the end stage of Step 1 is the reaction mixture (1). It was 5.00% on the basis of the amount of the arylene unit therein, and it was confirmed that the reaction in Step 1 proceeded to Step 2 after sufficiently proceeding. Moreover, sodium thiophenolate was not detected at all. Further, a part of the reaction mixture (1) at the end of step 1 is dispersed in a large excess of water to recover water-insoluble components and then dried to measure the weight average molecular weight of the solid content obtained by drying. Then, Mw = 3,400.

  As a result of analyzing the reaction mixture (2) recovered after completion of the operation at the stage where the process was performed up to the process 2 after the process 1, the residual amount of the dihalogenated aromatic compound at the completion stage of the process 2 was found in the reaction mixture (2). It was 5.40% based on the amount of the arylene unit, and it was confirmed that the reaction in Step 2 proceeded to Step 3 after sufficiently proceeding.

  As described above, according to the method for producing a cyclic PAS of the present invention, a high-purity cyclic PAS with a low impurity content can be obtained at a high production rate, and solid-liquid separation in the production process of the cyclic PAS can be achieved. It was found that the efficiency was extremely high and the productivity was extremely excellent.

[Comparative Example 1]
Here, an example in which cyclic PAS was produced under the condition that the number of arylene units per 1 mol of sulfur component in the reaction mixture was 1.00 mol from the charging of the raw material to the completion of the reaction without performing additional DCB operation. Indicates.

<Preparation of reaction mixture>
In an autoclave with a stirrer (material is SUS316L), 28.1 g of a 48 wt% sodium hydrosulfide aqueous solution (0.241 mol as sodium hydrosulfide) as a sulfidizing agent (a), 21.1 g of a 48 wt% sodium hydroxide aqueous solution (0.253 mol as sodium hydroxide), 35.4 g (0.241 mol) of p-dichlorobenzene (p-DCB) as dihalogenated aromatic compound (b), and N— as organic polar solvent (c) A reaction mixture was prepared by charging 600 g (0.585 L) of methyl-2-pyrrolidone (NMP). The amount of water contained in the raw material is 25.6 g (1.42 mol), and the amount of solvent per mole of sulfur component in the reaction mixture (per mole of sulfur atoms contained in sodium hydrosulfide charged as a sulfidizing agent) Was 2.43 L. In addition, an arylene unit (corresponding to p-DCB charged as a dihalogenated aromatic compound) per mole of sulfur component in the reaction mixture (per mole of sulfur atom contained in sodium hydrosulfide charged as a sulfidizing agent). The amount was 1.00 mol. Thereafter, the inside of the autoclave was replaced with nitrogen gas and sealed, and the temperature was raised from room temperature to 200 ° C. over about 1 hour while stirring at 400 rpm. Next, the temperature was raised from 200 ° C. to 250 ° C. over about 0.5 hour. The pressure in the reactor at this stage was 1.0 MPa as a gauge pressure. Thereafter, the reaction mixture was heated at 250 ° C. for 2 hours to be reacted.

  After that, 15 g of NMP alone was charged into a 100 mL small tank installed at the top of the autoclave via a high pressure valve, and after opening the small tank to about 1.5 MPa, the valve at the bottom of the tank was opened, and NMP was charged into the autoclave. . After this operation, the reaction was continued by continuing heating at 250 ° C. for another hour. After cooling to 230 ° C. over about 15 minutes, the steam composed mainly of NMP is discharged by gradually opening the high-pressure valve installed at the top of the autoclave, and this steam component is aggregated in the water-cooled cooling pipe. After recovering 394 g of liquid components, the high pressure valve was closed and sealed. Next, the reaction product was recovered by quenching to near room temperature.

<Analysis and evaluation of reaction products>
A part of the obtained reaction product was dispersed in a large excess of water to recover a component insoluble in water, and a component insoluble in the recovered water was dried to obtain a solid content. As a result of structural analysis by infrared spectroscopic analysis, it was confirmed that the solid content was a compound composed of phenylene sulfide units.

As a result of analyzing the obtained reaction product and the liquid components recovered in the liquid removal operation after the reaction by high performance liquid chromatography, it is compared with the case where all the sulfidizing agents in the reaction mixture are assumed to be converted to cyclic polyphenylene sulfide. The production rate of the cyclic polyphenylene sulfide determined by 1 was 15.6%. Moreover, the ratio of the peak area derived from other than cyclic PAS to the total peak area detected by high performance liquid chromatography of the reaction solution, that is, the impurity ratio was 1.5%. Moreover, as a result of evaluating the solid-liquid separability of the obtained reaction product, the filtration rate was 3 kg / (m ² · hr).

  As described above, the condition that the number of arylene units per 1 mol of the sulfur component in the reaction mixture is 1.00 mol from the addition of the raw material to the completion of the reaction without adding the dihalogenated aromatic compound, which is a feature of the present invention. When the cyclic PAS is produced in the above, the impurity ratio of the cyclic PAS can be kept low, but the production rate of the cyclic PAS is low, and the efficiency of solid-liquid separation in the cyclic PAS production process is also very high. It turned out to be bad.

[Comparative Example 2]
Here, in the preparation of the reaction mixture of Comparative Example 1, except that p-DCB was 38.9 g (0.265 mol) and the amount of arylene units per mol of sulfur component in the reaction mixture was 1.10 mol. An example in which cyclic PAS was produced in the same manner as in Comparative Example 1 is shown.

<Analysis and evaluation of reaction products>
A part of the obtained reaction product was dispersed in a large excess of water to recover a component insoluble in water, and a component insoluble in the recovered water was dried to obtain a solid content. As a result of structural analysis by infrared spectroscopic analysis, it was confirmed that the solid content was a compound composed of phenylene sulfide units.

As a result of analyzing the obtained reaction product by high performance liquid chromatography, the production rate of cyclic polyphenylene sulfide determined by comparison with the case where all the sulfidizing agents in the reaction mixture were assumed to be converted to cyclic polyphenylene sulfide was 16 0.0%. The ratio of the peak area derived from other than cyclic PAS to the total peak area detected by high performance liquid chromatography of the reaction solution, that is, the impurity ratio was 10.1%. Moreover, as a result of evaluating the solid-liquid separability of the obtained reaction product, the filtration rate was 350 kg / (m ² · hr).

  As described above, the condition that the arylene unit per mole of the sulfur component in the reaction mixture is 1.10 moles from the addition of the raw materials to the completion of the reaction without adding the dihalogenated aromatic compound, which is a feature of the present invention. When the cyclic PAS is produced in the above, the solid-liquid separation efficiency in the cyclic PAS production process is high, but the production rate of the cyclic PAS is low, and the impurity ratio in the reaction product is very high. I understood it.

Claims (11)

A reaction mixture comprising at least a sulfidizing agent (a), a dihalogenated aromatic compound (b) and an organic polar solvent (c), wherein 1.25 liters or more and 50 liters per mole of sulfur component in the reaction mixture A method for producing a cyclic polyarylene sulfide by heating and reacting the reaction mixture containing the following organic polar solvent (c):
The dihalogenated aromatic compound (b) in the reaction mixture is heated by heating the reaction mixture having an arylene unit of 0.80 mol or more and less than 0.95 mol per mol of the sulfur component in the reaction mixture. A step 1 of obtaining a reaction mixture (1) by reacting until the amount of arylene units in the reaction mixture is 10 mol% or less based on the amount;
Following step 1, the dihalogenated aromatic compound (b) is added so that the arylene unit per mole of sulfur component in the reaction mixture (1) is 0.95 mol or more and less than 1.05 mol, and the dihalogenated aromatic compound is added. A step 2 in which the group compound (b) is reacted by heating until the amount of the arylene unit is 10 mol% or less based on the amount of the arylene unit, and a reaction mixture (2) is obtained;
Following step 2, the dihalogenated aromatic compound (b) is added to the reaction mixture (2) so that the number of arylene units per mole of sulfur component is 1.05 mol or more and 1.50 mol or less, followed by further heating. Step 3 to obtain a reaction product containing at least cyclic polyarylene sulfide and linear polyarylene sulfide;
A process for producing a cyclic polyarylene sulfide comprising The ring according to claim 1, wherein in step 1, the dihalogenated aromatic compound (b) in the reaction mixture is reacted until it is 7 mol% or less based on the amount of arylene units in the reaction mixture. A process for producing a polyarylene sulfide. The cyclic polyarylene according to claim 1 or 2, wherein in step 2, the dihalogenated aromatic compound (b) is reacted by heating until it is 7 mol% or less based on the amount of the arylene unit. A method for producing sulfide. Following the step 3, the reaction product is subjected to solid-liquid separation in a temperature region below the boiling point of the organic polar solvent (c) at normal pressure, thereby obtaining a filtrate containing the cyclic polyarylene sulfide and the organic polar solvent (c). The method for producing a cyclic polyarylene sulfide according to any one of claims 1 to 3, wherein Step 4 is obtained. The method for producing a cyclic polyarylene sulfide according to any one of claims 1 to 4, wherein the reaction mixture further contains a linear polyarylene sulfide (d). The method for producing a cyclic polyarylene sulfide according to claim 5, wherein the reaction mixture contains linear polyarylene sulfide (d) at the start of the reaction in Step 1. A method for producing the cyclic polyarylene sulfide according to claim 5 or 6,
A reaction mixture containing at least a sulfidizing agent (a), a dihalogenated aromatic compound (b), and an organic polar solvent (c), wherein 1.25 to 50 liters per mole of sulfur component in the reaction mixture A reaction mixture comprising an organic polar solvent (c) of
The reaction mixture in which the number of arylene units per mole of sulfur component in the reaction mixture is 0.80 mol or more and less than 0.95 mol is heated, and the dihalogenated aromatic compound (b) in the reaction mixture is heated in the reaction mixture. A step 1 of obtaining a reaction mixture (1) by reacting until the amount of the arylene unit is 10 mol% or less based on the amount of the arylene unit;
Following step 1, the dihalogenated aromatic compound (b) is added so that the arylene unit per mole of sulfur component in the reaction mixture (1) is 0.95 mol or more and less than 1.05 mol, and the dihalogenated aromatic compound is added. A step 2 in which the group compound (b) is reacted by heating until the amount of the arylene unit is 10 mol% or less based on the amount of the arylene unit, and a reaction mixture (2) is obtained;
Following step 2, the dihalogenated aromatic compound (b) is added to the reaction mixture (2) so that the number of arylene units per mole of sulfur component is 1.05 mol or more and 1.50 mol or less, followed by further heating. Step 3 to obtain a reaction product containing at least cyclic polyarylene sulfide and linear polyarylene sulfide;
The linear polyarylene sulfide obtained by separating the cyclic polyarylene sulfide from the polyarylene sulfide mixture containing the cyclic polyarylene sulfide and the linear polyarylene sulfide obtained by heating and reacting by a method including A process for producing a cyclic polyarylene sulfide using an arylene sulfide as the linear polyarylene sulfide (d). A method for producing the cyclic polyarylene sulfide according to claim 5 or 6,
A reaction mixture comprising at least a linear polyarylene sulfide (d), a sulfidizing agent (a), a dihalogenated aromatic compound (b) and an organic polar solvent (c), and relative to 1 mol of a sulfur component in the reaction mixture Reaction mixture containing 1.25 liters to 50 liters of organic polar solvent (c),
The reaction mixture in which the number of arylene units per mole of sulfur component in the reaction mixture is 0.80 mol or more and less than 0.95 mol is heated, and the dihalogenated aromatic compound (b) in the reaction mixture is heated in the reaction mixture. A step 1 of obtaining a reaction mixture (1) by reacting until the amount of the arylene unit is 10 mol% or less based on the amount of the arylene unit;
Following step 1, the dihalogenated aromatic compound (b) is added so that the arylene unit per mole of sulfur component in the reaction mixture (1) is 0.95 mol or more and less than 1.05 mol, and the dihalogenated aromatic compound is added. A step 2 in which the group compound (b) is reacted by heating until the amount of the arylene unit is 10 mol% or less based on the amount of the arylene unit, and a reaction mixture (2) is obtained;
Following step 2, the dihalogenated aromatic compound (b) is added to the reaction mixture (2) so that the number of arylene units per mole of sulfur component is 1.05 mol or more and 1.50 mol or less, followed by further heating. Step 3 to obtain a reaction product containing at least cyclic polyarylene sulfide and linear polyarylene sulfide;
The linear polyarylene sulfide obtained by separating the cyclic polyarylene sulfide from the polyarylene sulfide mixture containing the cyclic polyarylene sulfide and the linear polyarylene sulfide obtained by heating and reacting by a method including A process for producing a cyclic polyarylene sulfide using an arylene sulfide as the linear polyarylene sulfide (d). When linear polyarylene sulfide is contained in the reaction mixture at the start of the reaction in Step 1, the content of the linear polyarylene sulfide is 0.001 mol or more per mol of sulfur component of the sulfidizing agent in the reaction mixture. The method for producing a cyclic polyarylene sulfide according to claim 5 or 6, wherein the number is less than a mole. The content of the aryl monothiolate compound in the reaction mixture (1) at the end of step 1 is less than 0.01 mol per mol of arylene units in the reaction mixture (1). The manufacturing method of cyclic polyarylene sulfide in any one of these. The method for producing a cyclic polyarylene sulfide according to any one of claims 1 to 10, wherein the heating in Step 2 and Step 3 is performed at a temperature higher than the heating temperature in Step 1.