JP6003347B2 - Method for producing polyarylene sulfide resin - Google Patents

Description

  The present invention relates to a method for producing a polyarylene sulfide resin. More specifically, the present invention relates to a method for producing a polyarylene sulfide resin using a carboxyalkylamino group-containing compound discharged in the production process of the polyarylene sulfide resin as a part of the raw material.

  A polyarylene sulfide resin (PAS resin) typified by a polyphenylene sulfide resin is excellent in heat resistance and chemical resistance, and is widely used for electrical and electronic parts, automobile parts, water heater parts, fibers, films and the like. In particular, in applications such as packing for lithium ion batteries and gasket members, in recent years, high molecular weight polyarylene sulfide resins have been widely used because of their excellent toughness and moldability.

  The polyarylene sulfide resin is produced by a polymerization reaction between a sulfidizing agent and a polyhaloaromatic compound in an aprotic polar solvent such as N-methyl-2-pyrrolidone (hereinafter sometimes abbreviated as NMP). In addition to the target polyarylene sulfide resin, a solvent, an alkali metal-containing inorganic salt such as sodium chloride, and the following general formula (1)

（式中、ｎは０〜２であり、Ｙ^１はハロゲン原子を、Ｙ^２は水素原子又はハロゲン原子を、Ｒ^１は水素原子又は炭素原子数１〜３のアルキル基又はシクロヘキシル基を表し、Ｒ^２は炭素原子数３〜５のアルキレン基を、Ｘは水素原子又はアルカリ金属原子を表す。）で表されるカルボキシアルキルアミノ基含有化合物などの有機塩といった副生成物を含有する粗反応生成物が得られる。重合反応後の粗反応生成物は適当な容器に取り出され、粗反応生成物中の溶媒は溶媒乾燥装置、濾過器、遠心分離器等の適当な固液分離装置を用いて脱溶媒処理により分離回収される（本操作を脱溶媒という）。

Wherein n is 0 to 2, Y ¹ represents a halogen atom, Y ² represents a hydrogen atom or a halogen atom, R ¹ represents a hydrogen atom, an alkyl group having 1 to 3 carbon atoms, or a cyclohexyl group; R ² represents an alkylene group having 3 to 5 carbon atoms, and X represents a hydrogen atom or an alkali metal atom.) A crude reaction product containing a by-product such as an organic salt such as a carboxyalkylamino group-containing compound A thing is obtained. The crude reaction product after the polymerization reaction is taken out into an appropriate container, and the solvent in the crude reaction product is separated by solvent removal using an appropriate solid-liquid separation device such as a solvent drying device, a filter, or a centrifuge. It is recovered (this operation is called desolvation).

  Furthermore, since the reaction product obtained after the desolvation treatment contains by-products such as the organic metal salt such as the alkali metal-containing inorganic salt and the carboxyalkylamino group-containing compound together with the target polyarylene sulfide resin, Filtration is repeated to remove these by-products. In general, there are a water washing method performed at less than 100 ° C. and a hot water washing performed at a high temperature and high pressure of 100 ° C. or higher. The polyarylene sulfide obtained after washing with water or hot water is separated with a filter, a centrifugal filter or the like, then dried, and subjected to a heat treatment as necessary to obtain a product.

  On the other hand, wastewater obtained after washing with water or hot water has been treated as industrial waste and has not been effectively utilized. However, since organic salts such as carboxyalkylamino group-containing compounds contained in these wastewaters cause COD loading, it has been required to reduce COD substances in order to reduce environmental burden.

  However, the wastewater also contains an alkali metal-containing inorganic salt such as sodium chloride, and it was difficult to separate the alkali metal-containing inorganic salt from the carboxyalkylamino group-containing compound.

  As a treatment method for reducing COD substances in wastewater, for example, an acid flocculant is added to wastewater to adjust pH, so that COD substances are insolubilized, and insolubilized COD substances are separated. Etc. are known (see Patent Document 1). However, in this method, the waste water of the purification process is introduced, the mixing function is provided, and the aggregation reaction tank equipped with the pH indicating controller and capable of pH adjustment and aggregation treatment is introduced from the aggregation reaction tank. Since the separation is performed using a continuous centrifugal separator that separates the insolubilized COD material, the water content of the separated COD material is high and cannot be reused as a raw material for producing the polyarylene sulfide resin. Moreover, since the COD substance separated by the acidic flocculant is precipitated in a large floc form, it must be treated as industrial waste, which is not preferable.

  For this reason, the present inventors modify the carboxyalkylamino group-containing compound terminal in the wastewater to carboxylic acid by acid treatment of the wastewater that has been discarded so far, and then add a water-insoluble solvent such as xylene. Thus, a method for removing an aqueous solution containing an alkali metal-containing inorganic salt and separating a carboxyalkylamino group-containing compound was clarified (Japanese Patent Application No. 2012-139697).

JP 2003-275773 A

  Accordingly, the problem to be solved by the present invention is a method for reusing a carboxyalkylamino group-containing compound discharged in the process for producing a polyarylene sulfide resin, in particular, a polyarylene for reuse as a production raw material for a polyarylene sulfide resin. It is providing the manufacturing method of sulfide resin.

  As a result of various investigations, the inventors of the present application modified the terminal of the carboxyalkylamino group-containing compound into a carboxylic acid by acidic treatment of an aqueous solution containing the alkali metal-containing inorganic salt and the carboxyalkylamino group-containing compound, By adding a water-insoluble solvent, the carboxyalkylamino group-containing compound can be separated from the aqueous solution containing the alkali metal-containing inorganic salt. Further, the water-insoluble solvent containing the separated carboxyalkylamino group-containing compound is alkaline. By adding the solution, the water-insoluble solvent is removed to obtain an alkaline aqueous solution containing the carboxyalkylamino group-containing compound efficiently, and the alkaline aqueous solution containing the carboxyalkylamino group-containing compound is a method for producing a polyarylene sulfide resin Can be reused as raw material It found that it is a performance, which resulted in the completion of the present invention.

  That is, the present invention provides the following general formula (1)

（式中、ｎは０〜２であり、Ｙ^１はハロゲン原子を、Ｙ^２は水素原子又はハロゲン原子を、Ｒ^１は水素原子又は炭素原子数１〜３のアルキル基又はシクロヘキシル基を表し、Ｒ^２は炭素原子数３〜５のアルキレン基を、Ｘは水素原子又はアルカリ金属原子を表す。）で表されるカルボキシアルキルアミノ基含有化合物を含むアルカリ性水溶液と、非プロトン性極性溶媒と、ポリハロ芳香族化合物と、（ｉ）アルカリ金属硫化物とを、または、（ｉｉ）アルカリ金属水硫化物及びアルカリ金属水酸化物とを混合し、前記非プロトン性極性溶媒中で、前記カルボキシアルキルアミノ基含有化合物と、ポリハロ芳香族化合物と、（ｉ）アルカリ金属硫化物とを、または、（ｉｉ）アルカリ金属水硫化物及びアルカリ金属水酸化物とを反応させて、ポリアリーレンスルフィド樹脂とアルカリ金属含有無機塩と前記カルボキシアルキルアミノ基含有化合物と非プロトン性極性溶媒を含む粗反応混合物を得る重合工程（ａ）、
前記粗反応混合物から非プロトン性極性溶媒を固液分離させてポリアリーレンスルフィド樹脂とアルカリ金属含有無機塩と前記カルボキシアルキルアミノ基含有化合物を含む反応混合物を得る固液分離工程（ａ）、
固液分離工程で得られた前記反応混合物を水と接触させて、ポリアリーレンスルフィド樹脂を濾別し、該ポリアリーレンスルフィド樹脂を回収する精製工程（ａ）、
を有することを特徴とするポリアリーレンスルフィド樹脂の製造方法、に関する。

Wherein n is 0 to 2, Y ¹ represents a halogen atom, Y ² represents a hydrogen atom or a halogen atom, R ¹ represents a hydrogen atom, an alkyl group having 1 to 3 carbon atoms, or a cyclohexyl group; R ² represents an alkylene group having 3 to 5 carbon atoms, and X represents a hydrogen atom or an alkali metal atom.), An aprotic polar solvent, a polyhalo, An aromatic compound and (i) an alkali metal sulfide, or (ii) an alkali metal hydrosulfide and an alkali metal hydroxide are mixed, and the carboxyalkylamino group is mixed in the aprotic polar solvent. A containing compound, a polyhaloaromatic compound, and (i) an alkali metal sulfide, or (ii) an alkali metal hydrosulfide and an alkali metal hydroxide, and A polymerization step (a) for obtaining a crude reaction mixture comprising a polyarylene sulfide resin, an alkali metal-containing inorganic salt, the carboxyalkylamino group-containing compound and an aprotic polar solvent;
A solid-liquid separation step (a) for obtaining a reaction mixture containing a polyarylene sulfide resin, an alkali metal-containing inorganic salt and the carboxyalkylamino group-containing compound by solid-liquid separation of the aprotic polar solvent from the crude reaction mixture;
A purification step (a) in which the reaction mixture obtained in the solid-liquid separation step is brought into contact with water, the polyarylene sulfide resin is separated by filtration, and the polyarylene sulfide resin is recovered;
And a process for producing a polyarylene sulfide resin.

  According to the present invention, a method for reusing a carboxyalkylamino group-containing compound discharged in a process for producing a polyarylene sulfide resin, in particular, a method for producing a polyarylene sulfide resin that is reused as a raw material for producing a polyarylene sulfide resin. Can be provided.

  The method for producing the polyarylene sulfide resin of the present invention has the following general formula (1).

（式中、ｎは０〜２であり、Ｙ^１はハロゲン原子を、Ｙ^２は水素原子又はハロゲン原子を、Ｒ^１は水素原子又は炭素原子数１〜３のアルキル基又はシクロヘキシル基を表し、Ｒ^２は炭素原子数３〜５のアルキレン基を、Ｘは水素原子又はアルカリ金属原子を表す。）で表されるカルボキシアルキルアミノ基含有化合物を含むアルカリ性水溶液と、非プロトン性極性溶媒と、ポリハロ芳香族化合物と、（ｉ）アルカリ金属硫化物とを、または、（ｉｉ）アルカリ金属水硫化物及びアルカリ金属水酸化物とを混合し、前記非プロトン性極性溶媒中で、前記カルボキシアルキルアミノ基含有化合物と、ポリハロ芳香族化合物と、（ｉ）アルカリ金属硫化物とを、または、（ｉｉ）アルカリ金属水硫化物及びアルカリ金属水酸化物とを反応させて、ポリアリーレンスルフィド樹脂とアルカリ金属含有無機塩と前記カルボキシアルキルアミノ基含有化合物と非プロトン性極性溶媒を含む粗反応混合物を得る重合工程（ａ）、
前記粗反応混合物から非プロトン性極性溶媒を固液分離させてポリアリーレンスルフィド樹脂とアルカリ金属含有無機塩と前記カルボキシアルキルアミノ基含有化合物を含む反応混合物を得る固液分離工程（ａ）、
固液分離工程で得られた前記反応混合物を水と接触させて、ポリアリーレンスルフィド樹脂を濾別し、該ポリアリーレンスルフィド樹脂を回収する精製工程（ａ）、
を有する。

Wherein n is 0 to 2, Y ¹ represents a halogen atom, Y ² represents a hydrogen atom or a halogen atom, R ¹ represents a hydrogen atom, an alkyl group having 1 to 3 carbon atoms, or a cyclohexyl group; R ² represents an alkylene group having 3 to 5 carbon atoms, and X represents a hydrogen atom or an alkali metal atom.), An aprotic polar solvent, a polyhalo, An aromatic compound and (i) an alkali metal sulfide, or (ii) an alkali metal hydrosulfide and an alkali metal hydroxide are mixed, and the carboxyalkylamino group is mixed in the aprotic polar solvent. A containing compound, a polyhaloaromatic compound, and (i) an alkali metal sulfide, or (ii) an alkali metal hydrosulfide and an alkali metal hydroxide, and A polymerization step (a) for obtaining a crude reaction mixture comprising a polyarylene sulfide resin, an alkali metal-containing inorganic salt, the carboxyalkylamino group-containing compound and an aprotic polar solvent;
A solid-liquid separation step (a) for obtaining a reaction mixture containing a polyarylene sulfide resin, an alkali metal-containing inorganic salt and the carboxyalkylamino group-containing compound by solid-liquid separation of the aprotic polar solvent from the crude reaction mixture;
A purification step (a) in which the reaction mixture obtained in the solid-liquid separation step is brought into contact with water, the polyarylene sulfide resin is separated by filtration, and the polyarylene sulfide resin is recovered;
Have

<Polymerization step (a)>
In the polymerization step (a), first, the following general formula (1)

（式中、ｎは０〜２であり、Ｙ^１はハロゲン原子を、Ｙ^２は水素原子又はハロゲン原子を、Ｒ^１は水素原子又は炭素原子数１〜３のアルキル基又はシクロヘキシル基を表し、Ｒ^２は炭素原子数３〜５のアルキレン基を、Ｘは水素原子又はアルカリ金属原子を表す。）で表されるカルボキシアルキルアミノ基含有化合物を含むアルカリ性水溶液と、非プロトン性極性溶媒と、ポリハロ芳香族化合物と、（ｉ）アルカリ金属硫化物とを、または、（ｉｉ）アルカリ金属水硫化物及びアルカリ金属水酸化物とを混合する。

Wherein n is 0 to 2, Y ¹ represents a halogen atom, Y ² represents a hydrogen atom or a halogen atom, R ¹ represents a hydrogen atom, an alkyl group having 1 to 3 carbon atoms, or a cyclohexyl group; R ² represents an alkylene group having 3 to 5 carbon atoms, and X represents a hydrogen atom or an alkali metal atom.), An aprotic polar solvent, a polyhalo, An aromatic compound and (i) an alkali metal sulfide or (ii) an alkali metal hydrosulfide and an alkali metal hydroxide are mixed.

  The alkaline aqueous solution containing the carboxyalkylamino group-containing compound used in the polymerization step (a) of the present invention can be produced through the following steps 1 to 5, for example.

・ Process 1
The present invention relates to an alkali metal-containing inorganic salt and the following general formula (1)

（式中、ｎは０〜２であり、Ｙ^１はハロゲン原子を、Ｙ^２は水素原子又はハロゲン原子を、Ｒ^１は水素原子又は炭素原子数１〜３のアルキル基又はシクロヘキシル基を表し、Ｒ^２は炭素原子数３〜５のアルキレン基を、Ｘは水素原子又はアルカリ金属原子を表す。）で表されるカルボキシアルキルアミノ基含有化合物を含む水溶液をｐＨ６．０以下に調整する工程である。

Wherein n is 0 to 2, Y ¹ represents a halogen atom, Y ² represents a hydrogen atom or a halogen atom, R ¹ represents a hydrogen atom, an alkyl group having 1 to 3 carbon atoms, or a cyclohexyl group; R ² represents an alkylene group having 3 to 5 carbon atoms, and X represents a hydrogen atom or an alkali metal atom.) This is a step of adjusting an aqueous solution containing a carboxyalkylamino group-containing compound represented by pH 6.0 or lower. .

  Here, the preparation of the aqueous solution containing the alkali metal-containing inorganic salt and the carboxyalkylamino group-containing compound is at least an aqueous solution containing the alkali metal-containing inorganic salt and the carboxyalkylamino group-containing compound, The inorganic salt is contained in the range of 0.1 to 26% by mass and the carboxyalkylamino group-containing compound is contained in the range of 0.01 to 5% by mass and substantially free of polyarylene sulfide resin. Do. The preparation method of the aqueous solution containing the alkali metal-containing inorganic salt and the carboxyalkylamino group-containing compound may be any method as long as the above composition can be prepared, but the water containing the alkali metal-containing inorganic salt and the carboxyalkylamino group-containing compound may be used. What is necessary is just to adjust to pH 10.0-13.0 by adding an alkali and to melt | dissolve by heating in the range of 40-90 degreeC. Moreover, the aqueous solution containing the alkali metal containing inorganic salt obtained by the refinement | purification process of polyarylene sulfide resin polymerization and the said carboxyalkylamino group containing compound can also be used. However, the aqueous solution containing the alkali metal-containing inorganic salt and the carboxyalkylamino group-containing compound substantially does not contain a polyarylene sulfide resin, which basically means that it is below the detection limit, When adjusted in the purification process of the polyarylene sulfide resin, a very small amount of the polyarylene sulfide resin may be contained depending on the method of purification and its degree, and the concentration of the polyarylene sulfide resin in the aqueous solution The sulfide resin concentration is 1 ppm or less, and even when it is large, it is 5 ppm or less.

  A method for obtaining an aqueous solution containing an alkali metal-containing inorganic salt and the carboxyalkylamino group-containing compound in the purification step of polyarylene sulfide resin polymerization includes an aprotic polar solvent, a polyhaloaromatic compound, and (i) an alkali metal sulfide. Or (ii) an alkali metal hydrosulfide and an alkali metal hydroxide, and a polyhaloaromatic compound and (i) an alkali metal sulfide in an aprotic polar solvent, or (Ii) reacting an alkali metal hydrosulfide and an alkali metal hydroxide to obtain a crude reaction mixture containing a polyarylene sulfide resin, an alkali metal-containing inorganic salt, the carboxyalkylamino group-containing compound, and the organic polar solvent. Polymerization step (b), solid-liquid separation of the organic polar solvent from the crude reaction mixture A solid-liquid separation step (b) for obtaining a reaction mixture containing a hydride resin, an alkali metal-containing inorganic salt and the carboxyalkylamino group-containing compound, contacting the reaction mixture with water, filtering off the polyarylene sulfide resin, The method which passes through the refinement | purification process (b) which collect | recovers the aqueous solution containing a metal containing inorganic salt and the said carboxyalkylamino group containing compound can be mentioned.

..Polymerization process (b)
The polyhaloaromatic compound used in the polymerization step (b) is, for example, a halogenated aromatic compound having two or more halogen atoms directly bonded to an aromatic ring, specifically, p-dichlorobenzene, o-dichlorobenzene, m-dichlorobenzene, trichlorobenzene, tetrachlorobenzene, dibromobenzene, diiodobenzene, tribromobenzene, dibromonaphthalene, triiodobenzene, dichlorodiphenylbenzene, dibromodiphenylbenzene, di And dihaloaromatic compounds such as chlorobenzophenone, dibromobenzophenone, dichlorodiphenyl ether, dibromodiphenyl ether, dichlorodiphenyl sulfide, dibromodiphenyl sulfide, dichlorobiphenyl, dibromobiphenyl, and mixtures thereof. These compounds may be block copolymerized. Of these, dihalogenated benzenes are preferred, and those containing p-dichlorobenzene of 80 mol% or more are particularly preferred.

  Further, for the purpose of increasing the viscosity of the polyarylene sulfide resin by using a branched structure, a polyhaloaromatic compound having 3 or more halogen substituents in one molecule may be used as a branching agent as desired. Examples of such polyhaloaromatic compounds include 1,2,4-trichlorobenzene, 1,3,5-trichlorobenzene, 1,4,6-trichloronaphthalene, and the like.

  Furthermore, polyhaloaromatic compounds having a functional group having active hydrogen such as amino group, thiol group, hydroxyl group can be mentioned. Specifically, 2,6-dichloroaniline, 2,5-dichloroaniline 2,4-dichloroaniline, 2,3-dichloroaniline and other dihaloanilines; 2,3,4-trichloroaniline, 2,3,5-trichloroaniline, 2,4,6-trichloroaniline, 3, Trihaloanilines such as 4,5-trichloroaniline; dihaloaminodiphenyl ethers such as 2,2′-diamino-4,4′-dichlorodiphenyl ether and 2,4′-diamino-2 ′, 4-dichlorodiphenyl ether Examples thereof include compounds in which the amino group is replaced by a thiol group or a hydroxyl group in a mixture thereof.

  In addition, active hydrogen-containing polyhalo compounds in which the hydrogen atom bonded to the carbon atom forming the aromatic ring in these active hydrogen-containing polyhaloaromatic compounds is substituted with another inert group, for example, a hydrocarbon group such as an alkyl group. Aromatic compounds can also be used.

  Among these various active hydrogen-containing polyhaloaromatic compounds, an active hydrogen-containing dihaloaromatic compound is preferable, and dichloroaniline is particularly preferable.

  Examples of the polyhaloaromatic compound having a nitro group include mono- or dihalonitrobenzenes such as 2,4-dinitrochlorobenzene and 2,5-dichloronitrobenzene; 2-nitro-4,4′-dichlorodiphenyl ether Dihalonitrodiphenyl ethers; dihalonitrodiphenyl sulfones such as 3,3′-dinitro-4,4′-dichlorodiphenyl sulfone; 2,5-dichloro-3-nitropyridine, 2-chloro-3,5 -Mono or dihalonitropyridines such as dinitropyridine; or various dihalonitronaphthalenes.

  The alkali metal sulfide used in the polymerization step (b) includes lithium sulfide, sodium sulfide, rubidium sulfide, cesium sulfide and a mixture thereof. Such alkali metal sulfides can be used as hydrates, aqueous mixtures or anhydrides. The alkali metal sulfide can also be derived from the reaction between an alkali metal hydrosulfide and an alkali metal hydroxide. Normally, a small amount of alkali metal hydroxide may be added to react with alkali metal hydrosulfide or alkali metal thiosulfate present in a trace amount in the alkali metal sulfide.

  The alkali metal hydrosulfide used in the polymerization step (b) includes lithium hydrosulfide, sodium hydrosulfide, rubidium hydrosulfide, cesium hydrosulfide, and mixtures thereof. Such alkali metal hydrosulfides can be used as hydrates, aqueous mixtures or anhydrides.

  Examples of the alkali metal hydroxide used in the polymerization step (b) include lithium hydroxide, sodium hydroxide, potassium hydroxide, rubidium hydroxide, cesium hydroxide and the like. It is also possible to use a mixture of two or more. Among these, lithium hydroxide, sodium hydroxide, and potassium hydroxide are preferable because they are easily available, and sodium hydroxide is particularly preferable.

  Examples of the aprotic polar solvent used in the polymerization step (b) include formamide, acetamide, N-methylformamide, N, N-dimethylacetamide, tetramethylurea, N-methyl-2-pyrrolidone, 2-pyrrolidone, N -Amides such as methyl-ε-caprolactam, ε-caprolactam, hexamethylphosphoramide, N-dimethylpropyleneurea, 1,3-dimethyl-2-imidazolidinone acid, urea and lactams; sulfolane, dimethylsulfolane, etc. Examples include sulfolanes; nitriles such as benzonitrile; ketones such as methyl phenyl ketone and mixtures thereof, among which N-methyl-2-pyrrolidone, 2-pyrrolidone, N-methyl-ε-caprolactam, ε-caprolactam, hexamethylphosphoramide N- dimethyl propylene urea, 1,3-dimethyl-2-amide having an aliphatic cyclic structure imidazolidinone acids are preferred, more preferably N- methyl-2-pyrrolidone.

  In the polymerization reaction of the polyarylene sulfide resin in the polymerization step (b), the alkali metal sulfide is reacted with the polyhaloaromatic compound as a sulfidizing agent in the presence of these aprotic polar solvents. Alternatively, in the polymerization reaction of the polyarylene sulfide resin, the alkali metal hydrosulfide and alkali metal hydroxide are reacted with the polyhaloaromatic compound as a sulfidizing agent in the presence of these aprotic polar solvents. The polymerization conditions are generally in the range of 200 to 330 ° C., and the pressure should be in such a range as to keep the polymerization solvent and the polymerization monomer polyhaloaromatic compound in a substantially liquid phase. It is selected from the range of 1-20 MPa, preferably from the range of 0.1-2 MPa. The charged amount of the polyhaloaromatic compound is in the range of 0.2 mol to 5.0 mol, preferably in the range of 0.8 to 1.3 mol, more preferably, with respect to 1 mol of the sulfur atom of the sulfidizing agent. It adjusts so that it may become the range of 0.9-1.1 mol. The amount of the aprotic polar solvent charged is in the range of 1.0 to 6.0 mol, preferably in the range of 2.5 to 4.5 mol, with respect to 1 mol of the sulfur atom of the sulfidizing agent. Prepare. The polymerization reaction is preferably performed in the presence of a small amount of water, and the proportion is preferably adjusted as appropriate in consideration of the polymerization method and the molecular weight and productivity of the polymer obtained. Specifically, the dehydration operation is performed so as to be in the range of 2.0 mol or less, preferably 1.6 mol or less with respect to 1 mol of the sulfur atom of the sulfidizing agent, and further dehydration in the presence of a polyhaloaromatic compound. In the case of performing the operation (for example, the method of “5)” in the following specific embodiment), 0.9 mol or less, preferably 0.05 to 0.3 mol, more preferably 0.01 to 0.02 mol or less. The dehydration operation may be performed so as to be in the range.

As a specific embodiment for polymerizing the sulfidizing agent and the polyhaloaromatic compound in the presence of the aprotic polar solvent described above, for example,
1) A method using a polymerization aid such as an alkali metal carboxylate or lithium halide,
2) A method using a crosslinking agent such as an aromatic polyhalogen compound,
3) A method in which a polymerization reaction is carried out in the presence of a small amount of water and then water is added for further polymerization,
4) During the reaction between the alkali metal sulfide and the aromatic dihalogen compound, a method of cooling the gas phase part of the reaction vessel to condense a part of the gas phase in the reaction vessel and refluxing it to the liquid phase, etc. .
5) In the presence of a polyhaloaromatic compound, an alkali metal sulfide, or a hydrous alkali metal hydrosulfide and an alkali metal hydroxide, and an amide, urea or lactam having an aliphatic cyclic structure are reacted while being dehydrated. Obtained through a step of producing a slurry containing a solid alkali metal sulfide, a step of adding a polar organic solvent such as NMP and dehydrating by distilling off water after producing the slurry, followed by a dehydration step. In the resulting slurry, a polyhaloaromatic compound, an alkali metal hydrosulfide, and an alkali metal salt of an amide, urea or lactam hydrolyzate having an aliphatic cyclic structure are mixed with 1 mol of a polar organic solvent such as NMP. In contrast, polyarylene sulfide having a process of performing polymerization by reacting at a water content of 0.02 mol or less in the reaction system as an essential process. Method for manufacturing a resin.

  Among these, when a polyarylene sulfide resin is produced by the polymerization methods 1) to 4), more by-products are produced, and therefore the COD value contained in the wastewater after purification tends to be high. For this reason, particularly when producing a polyarylene sulfide resin by the polymerization methods 1) to 4), it is preferable to reduce the carboxyalkylamino group-containing compound which is a COD-causing substance in wastewater by the method of the present invention.

  In the production of the polyarylene sulfide resin, as a raw material for producing the polyarylene sulfide resin, for example, when the organic polar solvent is N-methyl-2-pyrrolidone and the polyhaloaromatic compound is p-dichlorobenzene, the carboxyalkyl As an amino group-containing compound, the following general formula (3)

（式中、Ｘはアルカリ金属原子または水素原子を表す。）で表されるものが得られる（この化合物を“ＣＰ−ＭＡＢＡ”と略記する）。

(Wherein X represents an alkali metal atom or a hydrogen atom) is obtained (this compound is abbreviated as “CP-MABA”).

..Solid-liquid separation step (b)
Subsequently, a solid-liquid separation step (b) of obtaining a reaction mixture containing a polyarylene sulfide resin, an alkali metal-containing inorganic salt, and the carboxyalkylamino group-containing compound by solid-liquid separation of the aprotic polar solvent from the crude reaction mixture. )I do.

  That is, the solid-liquid separation step (b) includes the polyarylene sulfide resin, the alkali metal-containing inorganic salt, the carboxyalkylamino group-containing compound, and the aprotic polar solvent obtained after the completion of the polymerization of the polyarylene sulfide resin. In this step, the aprotic polar solvent is subjected to solid-liquid separation from the crude reaction mixture to obtain a reaction mixture containing a polyarylene sulfide resin, an alkali metal-containing inorganic salt and the carboxyalkylamino group-containing compound. The solid-liquid separation is roughly classified into two types, a flash method and a quench method described later. The flash method is a method of recovering a solvent by evaporating the solvent and simultaneously recovering a solid substance, and is generally performed by heating under reduced pressure to distill off the solvent.

  On the other hand, the quench method is a method in which the polymerization reaction product is removed by cooling to recover the particulate polyarylene sulfide resin. Generally, after cooling the reaction slurry in a reaction kettle, the polyarylene sulfide resin is crystallized. For example, a solid-liquid separation method may be used. Solid-liquid separation in the Quench method is a method in which after separation using a centrifugal separator such as filtration or screw decanter, water is directly added to the obtained filtration residue to form a slurry, and then solid-liquid separation is repeated. For example, a method of removing the remaining solvent by heating the filtered residue in a non-oxidizing atmosphere can be used. The flash method is preferable because solids can be collected relatively easily, and the quench method is easy to control the particle size of the polyarylene sulfide resin, and the polymer particles contain alkali metal-containing inorganic salts and other salts during crystallization. Since it becomes difficult to take in impurities, it is preferable in that a high-purity polymer is obtained.

..Purification process (b)
Subsequently, a purification step (b) is performed in which the reaction mixture is contacted with water to separate the polyarylene sulfide resin, thereby preparing an aqueous solution containing the alkali metal-containing inorganic salt and the carboxyalkylamino group-containing compound. .

  In the purification step (b), the reaction mixture is brought into contact with water (hereinafter, sometimes referred to as “washing”), followed by solid-liquid separation and filtration of the polyarylene sulfide resin. The reaction slurry obtained by solid-liquid separation of the organic polar solvent from the reaction mixture was added with water and stirred and then filtered using a filtration device, and the filtration residue containing moisture obtained by the above filtration (hereinafter “ Abbreviated as “water-containing cake”), and a method of adding water again to form a slurry and then filtering, or a method of adding water again and filtering while the water-containing cake is held in a filter.

  The amount of water added to the reaction slurry during the water washing is preferably in the range of 2 to 10 times the theoretical yield of the polyarylene sulfide finally obtained, from the viewpoint of washing efficiency, It is preferable to divide the water into 2 to 10 times, preferably 2 to 4 times, and wash it with water. The water washing is preferably performed in a nitrogen or air atmosphere in a water temperature range of 50 ° C. to 100 ° C. and a cleaning efficiency of 70 ° C. to 90 ° C., in particular. The water washing can be repeated once or a plurality of times. When water washing is repeated a plurality of times, the atmosphere and temperature conditions may be the same or different.

  The polyarylene sulfide resin separated by filtration may contain a trace amount of an alkali metal-containing inorganic salt or a carboxyalkylamino group-containing compound. Therefore, the polyarylene sulfide resin may be further solidified after contact with water in the range of 100 to 275 ° C. Liquid separation (hereinafter sometimes referred to as “hot water washing”), the polyarylene sulfide resin is filtered off, and the remaining aqueous solution containing the alkali metal-containing inorganic salt and the carboxyalkylamino group-containing compound can be extracted. This aqueous solution can also be used in the present invention.

  The temperature of the hot water washing is preferably in the range of 120 to 275 ° C., for example, from the viewpoint of good extraction efficiency of the carboxyalkylamino group-containing compound. More specifically, it is preferable to perform the extraction treatment with hot water at 140 to 260 ° C. under the condition that the pressure of the gas phase in the reactor is 0.2 to 4.6 MPa. By such hydrothermal treatment, the remaining alkali metal contained in the polyarylene sulfide resin and the carboxyalkylamino group-containing compound can be more efficiently extracted into water, and then the polyarylene sulfide resin is filtered. By separating, an aqueous solution containing an alkali metal-containing inorganic salt and a carboxyalkylamino group-containing compound can be obtained.

  As a specific method for performing such hot water washing, there is a method of washing the polyarylene sulfide resin filtered off after the water washing with stirring in water under a predetermined pressure condition and temperature condition in a pressure vessel. The amount of water at the time of hot water washing is preferably 1.5 times to 10 times the mass of polyarylene sulfide, from the point that the extraction efficiency of the carboxyalkylamino group-containing compound is good. The hot water washing may be performed in two or more times. For example, when hot water washing is repeated twice, it is preferable to perform filtration between the first hot water washing and the second hot water washing to remove the carboxyalkylamino group-containing compound extracted by the first hot water washing. Moreover, after performing hot water washing once, it may filter and may carry out an above described water washing. This operation also promotes the removal of the carboxyalkylamino group-containing compound. Moreover, although the conditions of the 1st hot water washing process and the 2nd hot water washing process can be selected arbitrarily from said conditions, the temperature of the 1st hot water washing process is the temperature which exists in the range of 120 to 200 degreeC, for example. After setting and removing the first highly alkaline filtrate by filtration, the temperature of the second hot water washing step is set to a temperature higher than the temperature of the first hot water washing step, for example, in the range of 150 ° C. to 275 ° C. It is preferable to implement it from the viewpoint of chemical resistance of the apparatus used in the hot water washing.

  The pH can be adjusted by adding an acid or base before solid-liquid separation (b), before hot water washing, during hot water washing or after hot water washing. In particular, in the carboxyalkylamino group-containing compound, X is an alkali metal. Since it becomes an atom and is easily extracted into water, it is preferable to control so that the pH after hot water washing is in the range of 11.0 or more and less than 13.0. Examples of the acid used at that time include hydrochloric acid, sulfuric acid, carbonic acid, acetic acid, and oxalic acid. Among these, carbonic acid, acetic acid, and oxalic acid are preferable. Further, carbon dioxide gas may be introduced and contacted at normal pressure or under pressure. On the other hand, examples of the base include alkali metal hydroxides such as lithium hydroxide, sodium hydroxide, and potassium hydroxide, or sodium carbonate, ammonium carbonate, sodium phosphate, and the like. Among these, sodium hydroxide is preferable.

  The water washing performed in the purification step (b) can be carried out using a water washing tank having a stirrer or a centrifuge for solid-liquid separation, but has a stirring blade inside the container and is filtered at the bottom. It can be carried out in a container having a mixing function provided with a filter. It is also possible to use a water washing tank having a stirrer or a centrifuge for solid-liquid separation even in hot water washing exceeding 100 ° C., but it has a stirring blade inside the container and is filtered at the bottom. It can be carried out in a closed type container provided with a filter for use or in a container having a mixing function capable of being sealed. In the present invention, water washing or hot water washing may be carried out continuously or in a batch manner.

  The filtered polyarylene sulfide resin may then be dried as it is to obtain a polyarylene sulfide resin powder. After further washing treatment, it is separated into solid and liquid, and dried to form a powder or granule. The polyarylene sulfide resin can be prepared.

  The aqueous solution containing the alkali metal-containing inorganic salt and the carboxyalkylamino group-containing compound prepared via the polymerization methods 1) to 4) described above tends to contain a large amount of the carboxyalkylamino group-containing compound. Although the amount depends on the degree of washing in the water washing step, it is generally 2000 [mg / L] or more from an industrial viewpoint, and even after water washing, the amount is 1500 [mg / L] or more. Moreover, in the aqueous solution containing the alkali metal-containing inorganic salt and the carboxyalkylamino group-containing compound prepared through the polymerization method of 5) above, the aqueous washing is generally performed at 1500 [mg / L] or more. Even the ratio is 1100 [mg / L] or more.

  The aqueous solution containing the alkali metal-containing inorganic salt and the carboxyalkylamino group-containing compound thus prepared is then adjusted to pH 6.0 or lower by adding an acid (step 1). Thereby, the general formula (1) mainly becomes a carboxyalkylamino group-containing compound (hereinafter referred to as carboxyalkylamino group-containing compound (a1)) in which X in the formula is a hydrogen atom. In order to further improve the separation efficiency in the subsequent step 2, the pH range is preferably in the range of 2.5 to 5.5, more preferably in the range of 3.5 to 4.5. Examples of the acid used in this case include hydrochloric acid, sulfuric acid, carbonic acid, and acetic acid. Among these, hydrochloric acid is preferable. The acid can be added in the range of 0 to 60 ° C., more preferably in the range of 10 to 40 ° C. and the pressure in the range of 0 to 1.0 Pa.

・ Process 2
Step 2 is a step of adding a water-insoluble solvent to the aqueous solution to separate the organic phase containing the carboxyalkylamino group-containing compound and the water-insoluble solvent into an aqueous phase containing an alkali metal-containing inorganic salt.

  In Step 2, a water-insoluble solvent is added to the aqueous solution containing the alkali metal-containing inorganic salt pH adjusted to acid and the carboxyalkylamino group-containing compound (a1) obtained in Step 1, and the carboxyalkylamino group is added. It isolate | separates into the organic phase containing a containing compound (a1) and a water-insoluble solvent, and the aqueous phase containing an alkali metal containing inorganic salt.

  The water-insoluble solvent is not particularly limited as long as it is an organic solvent that is mixed with water and then phase-separated, but long-chain aliphatic hydrocarbons such as n-hexane and n-heptane, cyclohexane, methyl Examples thereof include alicyclic hydrocarbons such as cyclohexane, aromatic hydrocarbons such as benzene, toluene and xylene, and halogenated hydrocarbons such as chloroform, chlorobenzene and dichlorobenzene.

  The amount of the water-insoluble solvent added in step 2 is not particularly limited as long as it is an amount that undergoes phase separation after mixing the aqueous solution and the water-insoluble solvent. Specifically, although depending on the type and concentration of the carboxyalkylamino group-containing compound (a1) in the water-insoluble solvent, the type of the solvent itself, etc., for example, 1 to 200 parts by mass with respect to 100 parts by mass of the aqueous solution The range is preferably 5 to 50 parts by mass.

The mixing of the aqueous solution and the water-insoluble solvent in the step 2 is, for example, a temperature range in which the water and the water-insoluble solvent do not coagulate and the water or the water-insoluble solvent does not evaporate, preferably 0 to 90 ° C. More preferably, a temperature range of 10 to 60 ° C. can be mentioned.
Mixing of the aqueous solution and the water-insoluble solvent in step 2 may be performed using a mixing device such as a stirring device or a static mixer.

・ Process 3
In step 3, an alkali metal-containing inorganic salt is obtained from an aqueous solution (aqueous phase) containing the alkali metal-containing inorganic salt phase-separated in step 2 and an organic phase containing the carboxyalkylamino group-containing compound and a water-insoluble solvent. This is a step of removing the aqueous phase, and recovering the organic phase containing the carboxyalkylamino group-containing compound and a water-insoluble solvent. The step of removing the separated organic phase and recovering the aqueous solution containing the alkali metal-containing inorganic salt is referred to as step 3 ′.

  The phase-separated carboxyalkylamino group-containing compound (a2), the organic phase containing a water-insoluble solvent, and the aqueous phase containing an alkali metal-containing inorganic salt are efficiently separated and recovered by known means. As such a method, it is possible to adopt separation and recovery means such as decantation after standing, but in order to increase the recovery efficiency, industrially, mixing for sufficient contact ( Step 2, Step 3 and Step 3 ′ using a so-called mixer / settler type separation / extraction device equipped with a (mixer) unit and a separation (settler) unit that separates this and keeps the respective counterflows uniform. Are preferably carried out simultaneously or sequentially.

  Further, the operation in step 3 can be performed in any of a pressurized state, a normal pressure state, and a reduced pressure state, and is preferably performed in a normal pressure state from the simplicity of the apparatus. Moreover, although it can also carry out in non-oxidizing atmospheres, such as nitrogen and a noble gas, it is preferable to carry out in air | atmosphere from the simplicity of an apparatus.

  In order to reduce the COD value, a water-insoluble solvent may be added to the phase-separated aqueous phase, and Step 2 and Step 3 'may be repeated again. Similarly, in order to improve the recovery rate of the carboxyalkylamino group-containing compound, a phase-separated aqueous phase and a water-insoluble solvent may be added, and Step 2 and Step 3 may be repeated again.

  In addition, the COD value of the aqueous solution containing the alkali metal-containing inorganic salt obtained through the step 3 ′ is compared with the COD value of the aqueous solution containing the alkali metal-containing inorganic salt and the carboxyalkylamino group-containing compound subjected to the step 1. , 20% or more, preferably 40% or more, and more preferably 70% or more. Furthermore, the carboxyalkylamino group-containing compound can be reduced to below the detection limit by repeating Step 2 and Step 3.

  Further, the carboxyalkylamino group-containing compound obtained through the step 3 is separated from the aqueous solution containing the alkali metal-containing inorganic salt and recovered as a solution containing the carboxyalkylamino group-containing compound and the water-insoluble solvent. The recovery rate (extraction rate) of the carboxyalkylamino group-containing compound is relative to the carboxyalkylamino group-containing compound contained in the aqueous solution containing the alkali metal-containing inorganic salt and the carboxyalkylamino group-containing compound subjected to Step 1. , 40% or more on a mass basis, preferably 50% or more, more preferably 75% or more, and still more preferably 90% or more. Furthermore, it is also possible to make it 99% or more by repeating the said process 2 and the process 4.

・ Process 4
Step 4 is a step of further separating the water-insoluble solvent by adding an alkaline aqueous solution to the solution containing the carboxyalkylamino group-containing compound (a1) recovered in Step 3 and the water-insoluble solvent.
In step 4, by adding an alkaline aqueous solution to the carboxyalkylamino group-containing compound (a1) in the composition, the carboxyalkylamino group-containing compound wherein X in the general formula (1) is an alkali metal atom is mainly used. (Hereinafter referred to as a carboxyalkylamino group-containing compound (a2)), which is separated on the aqueous phase side.

  The alkaline aqueous solution used in step 4 can be prepared using the same alkali metal hydroxide or alkali metal sulfide as used in the polymerization step of the polyarylene sulfide resin in step 1. There is no particular problem if the concentration of the alkali metal hydroxide or alkali metal sulfide in the alkaline aqueous solution is adjusted to be equal to or higher than that of the carboxyalkylamino group-containing compound (a1). The range is from 2 to 49% by mass, preferably from 1.0 to 10.0% by mass.

・ Process 5
Step 5 is an alkaline aqueous solution containing a carboxyalkylamino group-containing compound by removing the water-insoluble solvent from the aqueous solution containing the carboxyalkylamino group-containing compound (a2) phase-separated in Step 4 and the water-insoluble solvent. Is a step of recovering. The step of recovering the removed water-insoluble solvent is referred to as step 5 ′.

  In Step 5, after separating the aqueous solution containing the carboxyalkylamino group-containing compound (a2) and the water-insoluble solvent, the method of recovering the aqueous solution or water-insoluble solvent containing the carboxyalkylamino group-containing compound (a2) is as follows: This can be done by known means. As such a method, it is possible to adopt a separation and recovery means such as decantation after standing, but in order to increase the recovery efficiency in particular, a mixer / settler type separation / extraction device is used industrially. It is preferable to carry out. Note that the water-insoluble solvent recovered in step 5 'can be reused in step 2.

  The polymerization step (a) of the present invention comprises an alkaline aqueous solution containing a carboxyalkylamino group-containing compound obtained through the above step 5, a polyhaloaromatic compound, an aprotic polar solvent, and (i) an alkali metal sulfide. Or (ii) mixed with an alkali metal hydrosulfide and an alkali metal hydroxide, and in the aprotic polar solvent, the carboxyalkylamino group-containing compound, a polyhaloaromatic compound, and (i) an alkali A metal sulfide, or (ii) a reaction between an alkali metal hydrosulfide and an alkali metal hydroxide, a polyarylene sulfide resin, an alkali metal-containing inorganic salt, the carboxyalkylamino group-containing compound, and an aprotic compound This is a step of obtaining a crude reaction mixture containing a polar solvent. In the polymerization step (a), the aprotic polar solvent, polyhaloaromatic compound, alkali metal sulfide, alkali metal hydrosulfide and alkali metal hydroxide are the same as those used in the polymerization step (b). Can be used as well.

  Since the alkaline aqueous solution containing the carboxyalkylamino group-containing compound obtained through the step 5 is used as a raw material as an aqueous solution, the alkaline aqueous solution containing the carboxyalkylamino group-containing compound obtained through the step 5 and a polyhalo After mixing with an aromatic compound, an aprotic polar solvent, (i) an alkali metal sulfide, or (ii) an alkali metal hydrosulfide and an alkali metal hydroxide, an appropriate dehydration operation is performed for adjustment. It is preferable. The proportion is appropriately adjusted in view of the polymerization method and the molecular weight and productivity of the polymer to be obtained. Specifically, it is 2.0 mol or less, preferably 1. In the case where the dehydration operation is further performed in the presence of a polyhaloaromatic compound (for example, the method of 5-1 to 5-3 in the following specific embodiment), the amount is 0.9 mol or less. , Preferably 0.05 to 0.3 mol, more preferably 0.01 to 0.02 mol or less.

  In the polymerization step (a), the amount of the carboxyalkylamino group-containing compound is in the range of 0.5 to 10 mmol, preferably in the range of 1.5 to 8.0 mmol, with respect to 1 mol of the sulfur atom of the sulfidizing agent. Do as follows. Further, the charged amount of the polyhaloaromatic compound is in the range of 0.2 mol to 5.0 mol, preferably 0.8 to 1.3 mol with respect to 1 mol of the sulfur atom of the sulfiding agent at the start of the reaction. Is adjusted as appropriate, more preferably in the range of 0.9 to 1.1 mol.

  (I) alkali metal sulfide used as a sulfidizing agent, or (ii) among alkali metal hydrosulfide and alkali metal hydroxide, the amount of alkali metal hydroxide or alkali metal sulfide charged is When the alkali metal hydroxide or alkali metal sulfide contained in the alkaline aqueous solution containing the carboxyalkylamino group-containing compound obtained through the above step 5 is insufficient, a new alkali metal hydroxide or alkali is newly added. It can adjust suitably so that it may become in the said range by adding a metal sulfide.

  In the polymerization step (a), the polymerization reaction of the polyarylene sulfide resin is carried out by combining the alkali metal sulfide and the polyhaloaromatic compound as a sulfidizing agent in the presence of the aprotic polar solvent and the carboxyalkylamino group-containing compound. React. Alternatively, the polymerization reaction of the polyarylene sulfide resin is carried out in the presence of the aprotic polar solvent and the carboxyalkylamino group-containing compound, and the alkali metal hydrosulfide and alkali metal hydroxide as a sulfidizing agent, and a polyhaloaromatic compound. The compound is reacted. The polymerization conditions are generally in the range of 200 to 330 ° C., and the pressure should be in such a range as to keep the polymerization solvent and the polymerization monomer polyhaloaromatic compound in a substantially liquid phase. It is selected from the range of 1-20 MPa, preferably from the range of 0.1-2 MPa. The amount of the aprotic polar solvent charged is in the range of 1.0 to 6.0 mol, preferably in the range of 2.5 to 4.5 mol, with respect to 1 mol of the sulfur atom of the sulfidizing agent. adjust.

  In the polymerization step (a), the polymerization reaction of the polyarylene sulfide resin is carried out by combining the alkali metal sulfide and the polyhaloaromatic compound as a sulfidizing agent in the presence of the aprotic polar solvent and the carboxyalkylamino group-containing compound. React. Alternatively, the polymerization reaction of the polyarylene sulfide resin is carried out in the presence of the aprotic polar solvent and the carboxyalkylamino group-containing compound, and the alkali metal hydrosulfide and alkali metal hydroxide as a sulfidizing agent, and a polyhaloaromatic compound. The compound is reacted. The polymerization conditions are generally in the range of 200 to 330 ° C., and the pressure should be in such a range as to keep the polymerization solvent and the polymerization monomer polyhaloaromatic compound in a substantially liquid phase. It is selected from the range of 1-20 MPa, preferably from the range of 0.1-2 MPa. The charged amount of the polyhaloaromatic compound is in the range of 0.2 mol to 5.0 mol, preferably in the range of 0.8 to 1.3 mol with respect to 1 mol of the sulfur atom of the sulfiding agent at the start of the reaction. More preferably, it is adjusted to be in the range of 0.9 to 1.1 mol.

As a specific embodiment for polymerizing the sulfidizing agent and the polyhaloaromatic compound in the presence of the aprotic polar solvent and the carboxyalkylamino group-containing compound, for example,
1) A method using a polymerization aid such as an alkali metal carboxylate or lithium halide,
2) A method using a crosslinking agent such as an aromatic polyhalogen compound,
3) A method in which a polymerization reaction is carried out in the presence of a small amount of water and then water is added for further polymerization,
4) During the reaction between the alkali metal sulfide, the aromatic dihalogen compound and the carboxyalkylamino group-containing compound, the gas phase portion of the reaction vessel is cooled to condense part of the gas phase in the reaction vessel to the liquid phase. And a method of refluxing.

Furthermore, the following 5-1) to 5-3) are also mentioned as preferable methods.
5-1) Hydrous alkali metal sulfide, or hydrous alkali metal hydrosulfide and alkali metal hydroxide, and an amide having an aliphatic cyclic structure in the presence of the polyhaloaromatic compound and the carboxyalkylamino group-containing compound, A step of producing a slurry containing solid alkali metal sulfide by reacting urea or lactam while dehydrating, and after producing the slurry, a polar organic solvent such as NMP is further added, and water is distilled off for dehydration. In the slurry obtained through the dehydration step, a polyhaloaromatic compound, an alkali metal hydrosulfide, and an alkali metal salt of an amide, urea or lactam hydrolyzate having the aliphatic cyclic structure. And the amount of water existing in the reaction system with respect to 1 mol of a polar organic solvent such as NMP. Method for producing a polyarylene sulfide resin having a step of performing polymerization by reacting 0.02 mol as an essential production step.

5-2) In the presence of a polyhaloaromatic compound, hydrous alkali metal sulfide, hydrous alkali metal hydrosulfide and alkali metal hydroxide, and amide, urea or lactam having an aliphatic cyclic structure are dehydrated. The step of producing a slurry containing a solid alkali metal sulfide by reacting while adding the solution containing a carboxyalkylamino group-containing compound and an aprotic polar solvent, and distilling off the water. In the slurry obtained through the step of dehydration and then through the dehydration step, polyhaloaromatic compound, alkali metal hydrosulfide, alkali metal of hydrolyzate of amide, urea or lactam having the above aliphatic cyclic structure The salt and the carboxyalkylamino group-containing compound are present in the reaction system with respect to 1 mol of a polar organic solvent such as NMP. Method for producing a polyarylene sulfide resin having a step of content of which polymerization is carried out by reacting 0.02 mol as an essential production step.

5-3) In the presence of a polyhaloaromatic compound, hydrous alkali metal sulfide, hydrous alkali metal hydrosulfide and alkali metal hydroxide, and amide, urea or lactam having an aliphatic cyclic structure are dehydrated. A step of producing a slurry containing a solid alkali metal sulfide by reacting with the reaction, a step of adding a polar organic solvent such as NMP after the slurry is produced, and performing dehydration by distilling off water, followed by a dehydration step A solution containing a carboxyalkylamino group-containing compound and an aprotic polar solvent is added to the slurry obtained through the steps, and then, in the slurry, a polyhaloaromatic compound, an alkali metal hydrosulfide, and the aliphatic cyclic structure An amide, urea or lactam alkali metal salt having a carboxyalkylamino group-containing compound Method for producing a polyarylene sulfide resin amount of water existing in the reaction system has as an essential production step the step of performing the polymerization by reacting 0.02 moles or less with respect to polar organic solvents one mole of such.

<Solid-liquid separation step (a)>
Subsequently, a solid-liquid separation step (a) in which the aprotic polar solvent is solid-liquid separated from the crude reaction mixture to obtain a reaction mixture containing a polyarylene sulfide resin, an alkali metal-containing inorganic salt, and the carboxyalkylamino group-containing compound (a )I do. This step can be performed in the same manner as the solid-liquid separation step (b).

<Purification step (a)>
The present invention further includes a purification step (a) in which the reaction mixture obtained in the solid-liquid separation step is brought into contact with water to separate and recover the polyarylene sulfide resin. This step can be performed in the same manner as the purification step (b).

  The polyarylene sulfide resin separated by filtration is recovered and then dried as it is, and may be used as a polyarylene sulfide resin powder. Further, after washing treatment, solid-liquid separation is performed, and drying is performed to form a powder or granule. It can also be prepared as a polyarylene sulfide resin.

  Thus, although the carboxyalkylamino group-containing compound has been conventionally treated as industrial waste, it can be reused as a raw material in the polyarylene sulfide polymerization step by separating it from the alkali metal-containing inorganic salt. For this reason, industrial waste can be reduced by the present invention.

  As described above, the polyarylene sulfide resin polymerized using a carboxyalkylamino group-containing compound as a part of the raw material is within a range that does not impair the effects of the present invention, a release agent, a colorant, a heat stabilizer, an ultraviolet light stabilizer, Additives such as a foaming agent, a rust inhibitor, a flame retardant, a lubricant, a coupling agent, and a filler can be contained. Furthermore, the following synthetic resins and elastomers can also be mixed and used. These synthetic resins include polyester, polyamide, polyimide, polyetherimide, polycarbonate, polyphenylene ether, polysulfone, polyethersulfone, polyetheretherketone, polyetherketone, polyarylene, polyethylene, polypropylene, polytetrafluoroethylene, Examples thereof include poly (difluoroethylene), polystyrene, ABS resin, epoxy resin, silicone resin, phenol resin, urethane resin, and liquid crystal polymer. Examples of the elastomer include polyolefin rubber, fluorine rubber, and silicone rubber.

  The polyarylene sulfide resin thus obtained is excellent in heat resistance, moldability, dimensional stability, etc. by various melt processing methods such as injection molding, extrusion molding, compression molding, and blow molding, particularly with epoxy resin. A molded product having excellent adhesion can be produced. For this reason, for example, electrical / electronic parts such as connectors / printed boards / encapsulated molded products, automotive parts such as lamp reflectors / various electrical components, interior materials such as various buildings, aircraft / automobiles, or OA equipment parts / It can be widely used as injection molding / compression molding products such as precision parts such as camera parts and watch parts, or extrusion molding and pultrusion molding products such as fibers, films, sheets, and pipes.

  The present invention will be specifically described below with reference to examples. These examples are illustrative and not limiting.

[Reference Example 1] Production of polyarylene sulfide resin A 150 liter autoclave with a pressure gauge, a thermometer, a condenser connected with a stirring blade and a bottom valve, 45% sodium hydrosulfide (47.55 mass% NaSH) 14.148 kg, 48 % Caustic soda (48.7 wt% NaOH) 9.317 kg and N-methyl-2-pyrrolidone 38.0 kg were charged. While stirring under a nitrogen stream, the temperature was raised to 209 ° C. to distill 11.916 kg of water (the amount of water remaining was 1.13 mol per 1 mol of NaSH). Thereafter, the autoclave was sealed and cooled to 180 ° C., and 17.129 kg of paradichlorobenzene and 16.0 kg of N-methyl-2-pyrrolidone were charged. The temperature was raised by pressurizing to 0.1 MPa with a gauge pressure using nitrogen gas at a liquid temperature of 150 ° C. The reaction was allowed to proceed with stirring at a liquid temperature of 260 ° C. for 3 hours, and the upper part of the autoclave was sprinkled to cool it. Next, the temperature was lowered and cooling of the upper part of the autoclave was stopped. The upper part of the autoclave was kept constant during cooling to prevent the liquid temperature from dropping. The maximum pressure during the reaction was 0.86 MPa. After the reaction, it was cooled, the bottom valve was opened at a temperature of 100 ° C., the reaction slurry was transferred to a flat plate filter and filtered under pressure at 120 ° C., and 16.0 kg of N-methyl-2-pyrrolidone was added, followed by pressure filtration. . After filtration, the mixture was stirred for 2 hours at 150 ° C. under reduced pressure using a vacuum dryer with a stirring blade to distill off N-methyl-2-pyrrolidone. Next, 90 kg of 70 ° C. warm water was added and stirred, followed by filtration. Further, 25 kg of 70 ° C. warm water was added and filtered, and the filtrate was collected to prepare “aqueous solution (A)”. The CP-MABA concentration in the aqueous solution (A) was 1.84 [g / L], and the polyarylene sulfide resin concentration was 0 [mass%].

[Reference Example 2]
Hydrochloric acid was added to 30 L of the aqueous solution (A) while stirring to adjust the pH to 4.0, and then the aqueous solution (A) adjusted to pH and 3 L of p-xylene were placed in an autoclave equipped with a stirrer and a heating device, and 30 minutes at room temperature After stirring, stirring was stopped and allowed to stand. The bottom valve of the autoclave was opened in the decanter, and the organic solvent phase (upper layer) and the aqueous phase (lower layer) were separated with the decanter while transferring the content liquid. CP-MABA in the obtained organic solvent phase was 16.0 g / L.
Next, 10 L of organic solvent phase and 0.25 L of 3% caustic soda were put in a container equipped with a stirrer and stirred for 30 minutes, and then the whole amount was transferred to a decanter and allowed to stand. When the organic solvent phase and the aqueous phase were separated, the organic solvent phase and the aqueous phase were recovered. From the aqueous phase, an aqueous caustic soda solution containing 159 g / L of CP-MABA was obtained.

[Measurement method of CP-MABA]
The CP-MABA concentration in the aqueous solution (A) in Reference Example 1 and the CP-MABA concentration in the organic solvent phase in Reference Example 2 and the CP-MABA concentration in the finally obtained aqueous phase are the values of the prepared measurement samples. An HPLC measurement was performed, and the concentration in the liquid was determined and calculated from the peak area and calibration curve having the same retention time as the standard sample prepared by the following method.

(Sample preparation)
CP-MABA in the aqueous solution (A) or aqueous phase was prepared by adding the mobile phase as it was. On the other hand, CP-MABA in an organic solvent was prepared by distilling off the organic solvent with an evaporator and then adding an HPLC mobile phase to the residue and dissolving it.

(Standard sample: CP-MABA synthesis)
83.4 g (1.0 mol) of 48% NaOH aqueous solution and 297.4 g (3.0 mol) of N-methyl-2-pyrrolidone were charged in a pressure vessel equipped with a stirrer and stirred at 230 ° C. for 3 hours. After the stirring was completed, the valve was opened with the temperature kept at 230 ° C., the pressure was released, and the pressure was reduced to 0.1 MPa at 230 ° C., which is about the vapor pressure of N-methyl-2-pyrrolidone, and water was distilled off. Then, it sealed again and the temperature was reduced to about 200 degreeC.

  147.0 g (1.0 mol) of p-dichlorobenzene was heated and dissolved under a temperature condition of 60 ° C. or higher, charged into the reaction mixture, heated to 250 ° C., and stirred for 4 hours. After completion of this stirring, the mixture was cooled to room temperature. The reaction rate of p-dichlorobenzene was 31 mol%. After cooling, the contents were taken out, water was added, and the mixture was stirred. Unreacted p-dichlorobenzene remained as an insoluble matter and was removed by filtration.

  Next, hydrochloric acid was added to the aqueous solution as the filtrate to adjust the pH of the aqueous solution to 4. At this time, brown oily CP-MABA (hydrogen type) was formed in the aqueous solution. Chloroform was added thereto to extract a brown oily substance. Since the aqueous phase at this time contained N-methyl-2-pyrrolidone and its ring-opened product, 4-methylaminobutyric acid (hereinafter abbreviated as “MABA”), the aqueous phase was discarded. The chloroform phase was washed twice with water.

  In a state where water was added to the chloroform phase to form a slurry, a 48% NaOH aqueous solution was added to adjust the pH of the slurry to 13. At this time, CP-MABA was converted to a sodium salt and moved to the aqueous phase, and the chloroform phase was discarded because p-chloro-N-methylaniline and N-methylaniline as by-products were dissolved in the chloroform phase. The aqueous phase was washed twice with chloroform.

  Dilute hydrochloric acid was added to the aqueous solution to adjust the pH of the aqueous solution to 1 or less. At this time, CP-MABA became hydrochloride and remained in the aqueous solution, so chloroform was added to the aqueous solution to extract p-chlorophenol as a by-product. The chloroform phase in which p-chlorophenol was dissolved was discarded.

  A 48% aqueous NaOH solution was added to the remaining aqueous solution to adjust the pH of the aqueous solution to 4. As a result, the hydrochloride of CP-MABA was neutralized, and brown oily CP-MABA (hydrogen type) was precipitated from the aqueous solution. CP-MABA (hydrogen type) was extracted with chloroform, and chloroform was removed under reduced pressure to obtain CP-MABA (hydrogen type).

[Measurement of polyarylene sulfide resin concentration]
The polyarylene sulfide resin concentration in the aqueous solution (A) was measured as follows.
To 100 parts by mass of the aqueous solution (A), 20 parts by mass of chloroform was added, mixed and extracted with an analytical funnel, and separated to separate a chloroform layer and an aqueous layer. The chloroform layer was measured with a liquid chromatograph apparatus using chloroform as the mobile phase, and the area area (A) obtained by removing the peak of the carboxyalkylamino group-containing compound from the obtained peak was determined. However, the peak of the carboxyalkylamino group-containing compound was determined by measuring in advance a chloroform solution of the carboxyalkylamino group-containing compound at a predetermined concentration and measuring the retention time. Separately, the area area (B) of a chloroform solution having a polyarylene sulfide resin concentration of 0.32 wt% was obtained, and the polyarylene sulfide resin concentration in the aqueous solution (A) was calculated from the following formula.

[Example 1]
In an autoclave connected with a pressure gauge, a thermometer, and a condenser, 589.48 g of 45% sodium hydrosulfide (47.55 mass% NaSH), 393.41 g of 48% caustic soda (48.7 mass% NaOH) The obtained CP-MABA (159 g / L) -containing 3% sodium hydroxide aqueous solution (2.54% by mass NaOH) 25.11 g (containing CP-MABA 3.9 g) and N-methyl-2-pyrrolidone 1583 g were charged. While stirring under a nitrogen stream, the temperature was raised to 209 ° C. to distill 496.48 g of water (the amount of water remaining was 1.13 mol per 1 mol of NaSH). Thereafter, the autoclave was sealed and cooled to 180 ° C., and 713.09 g of p-dichlorobenzene and 667 g of N-methyl-2-pyrrolidone were charged. The temperature was raised by pressurizing to 0.1 MPa with a gauge pressure using nitrogen gas at a liquid temperature of 150 ° C. The reaction was allowed to proceed with stirring at a liquid temperature of 260 ° C. for 3 hours, and the upper part of the autoclave was sprinkled to cool it. Next, the temperature was lowered and cooling of the upper part of the autoclave was stopped. The upper part of the autoclave was kept constant during cooling to prevent the liquid temperature from dropping. The maximum pressure during the reaction was 0.86 MPa. After the reaction, the mixture was cooled, and at a temperature of 170 ° C., a solution containing 11.83 g (93.8 mmol) of oxalic acid dihydrate in 27.60 g of N-methyl-2-pyrrolidone was added and stirred for 30 minutes. And cooled to room temperature. The reaction slurry was heated to 120 ° C. and filtered under reduced pressure, and then dried under reduced pressure at 150 ° C. for 3 hours using a vacuum dryer equipped with a stirring blade to distill off N-methyl-2-pyrrolidone. Next, 3780 g of 70 ° C. warm water was added and stirred, followed by filtration. Further, 1080 g of 70 ° C. warm water was added and filtered. Further, 1080 g of hot water at 70 ° C. was added and heated at 160 ° C., followed by filtration. Then, 1080 g of hot water at 70 ° C. was added and filtered. The obtained hydrous cake was dried with a hot air circulating dryer at 120 ° C. for 12 hours to obtain a PPS resin (1). The melt viscosity (V6) of the obtained PPS resin (1), the carboxy group content in the PPS resin, and the CP-MABA content in the PPS resin were measured. The results are shown in Table 1 below.

[Example 2]
“39.41 g of 48% caustic soda (48.7 mass% NaOH) and 25.11 g of 3% caustic soda aqueous solution (2.54 mass% NaOH) containing CP-MABA (159 g / L) obtained in Reference Example 2 ( 3% aqueous caustic soda solution containing 392.11 g of “48% caustic soda (48.7% by mass NaOH)” and CP-MABA (159 g / L) obtained in Reference Example 2 instead of “containing CP-MABA 3.9 g” PPS resin (2) was obtained in the same manner as in Example 1 except that 50.06 g (containing 7.7 g of CP-MABA) was used. The melt viscosity (V6) of the obtained PPS resin (2), the carboxy group content in the PPS resin, and the CP-MABA content in the PPS resin were measured. The results are shown in Table 1 below.

Example 3
“39.41 g of 48% caustic soda (48.7 mass% NaOH) and 25.11 g of 3% caustic soda aqueous solution (2.54 mass% NaOH) containing CP-MABA (159 g / L) obtained in Reference Example 2 ( 3% caustic soda solution containing 394.58 g of “48% caustic soda (48.7 mass% NaOH)” and CP-MABA (159 g / L) obtained in Reference Example 2 instead of “CP-MABA containing 3.9 g” PPS resin (3) was obtained in the same manner as in Example 1 except that 5.04 g (containing CP4MABA 0.8 g) was used. The melt viscosity (V6) of the obtained PPS resin (3), the carboxy group content in the PPS resin, and the CP-MABA content in the PPS resin were measured. The results are shown in Table 1 below.

[Comparative Example 1]
In an autoclave connected with a pressure gauge, a thermometer, and a condenser, 589.48 g of 45% sodium hydrosulfide (47.55 mass% NaSH), 394.72 g of 48% caustic soda (48.7 mass% NaOH), N-methyl- 2-Pyrrolidone 1583g was charged. While stirring under a nitrogen stream, the temperature was raised to 209 ° C. to distill 496.48 g of water (the amount of water remaining was 1.13 mol per 1 mol of NaSH). Thereafter, the autoclave was sealed and cooled to 180 ° C., and 713.09 g of p-dichlorobenzene and 667 g of N-methyl-2-pyrrolidone were charged. Subsequent operations were performed in the same manner as in Example 1 to obtain PPS resin (4). The melt viscosity (V6) of the obtained PPS resin (4), the carboxy group content in the PPS resin, and the CP-MABA content in the PPS resin were measured. The results are shown in Table 1 below.

(Melt viscosity V6)
Using a flow tester (Shimadzu Corporation Koka-type flow tester “CFT-500D type”), the temperature / 300 ° C., the load 1.96 MPa, the orifice length / orifice diameter ratio is 10/1. The melt viscosity after holding for 6 minutes was measured using an orifice.

(Quantification of CP-MABA in PPS resin)
After adding 140 g of ion-exchanged water and 10 g of 0.1 mol / L sodium hydroxide aqueous solution to 50 g of PPS resin and stirring well, it is extracted from the peak area and calibration curve with the same retention time as the standard sample. The concentration in the liquid was determined, and the CP-MABA concentration in the PPS resin was calculated. Since CP-MABA (hydrogen type) is extracted by changing to CP-MABA (Na type) under alkaline conditions, this concentration is CP-MABA (hydrogen type) and CP-MABA (Na type) originally present. ) Total CP-MABA concentration.

(Quantification of carboxy group content in PPS resin)
A quantitative method is that a polyarylene sulfide resin is pressed at 350 ° C. and then rapidly cooled to prepare a film showing amorphous properties, which is measured with a Fourier transform infrared spectrometer (hereinafter abbreviated as “FT-IR device”). did. Determined the relative intensity of the absorption of 1705 cm ^-1 for absorption of 630.6Cm ^-1 of infrared absorption spectrum, the content of the carboxyl group in the measurement sample using a separately prepared calibration curve (hereinafter "carboxyl group content" For short). The content of the carboxy group was represented by the number of moles (μmol / g) in 1 g of PPS resin. A calibration curve was prepared by adding a predetermined amount of 4-chlorophenylacetic acid to 3 g of a polyarylene sulfide resin containing a carboxylate at the molecular end without acid treatment and mixing well, and then creating a film in the same manner as described above. Measurement was performed with an FT-IR apparatus, and a calibration curve in which the relative intensity ratio of the absorption to the carboxy group content was plotted was prepared.

[Examples 4 to 6, Comparative Example 2] Manufacture of test pieces 69.7 parts of PPS resins (1) to (4), 0.3 part of polyethylene wax, glass fiber (glass fiber having an average fiber diameter of 10 μm and a length of 3 mm) After mixing 40 parts of chopped strand), it was melt kneaded at a set resin temperature of 330 ° C. using a twin screw extruder to obtain PPS resin composition pellets. Subsequently, the PPS resin composition pellets were injection molded at a cylinder temperature of 320 ° C. and a mold temperature of 130 ° C. to obtain ASTM No. 1 dumbbell test pieces. The obtained ASTM No. 1 dumbbell test piece was divided into two equal parts from the center, and a spacer (thickness: 1.8 to 2.2 mm, opening: 5 mm ×) prepared so that the adhesion area with the epoxy adhesive was 50 mm ^2. 10 mm), and sandwiched between two ASTM No. 1 dumbbell test pieces, fixed using clips, and then an epoxy adhesive (two-component epoxy resin / main agent: XNR5002, manufactured by Nagase Chemtech Co., Ltd.) Curing agent: XNH5002, blending ratio was main agent: curing agent = 100: 90), and heated for 3 hours in a hot air circulating drier set at 135 ° C. to cure and bond. After leaving at room temperature for 1 day, the spacer was removed to obtain test pieces (1) to (4).

[Measurement of epoxy adhesive strength]
The obtained test specimens (1) to (4) were measured for tensile rupture strength using a tensile tester at a strain rate of 1 mm / min and a fulcrum distance of 80 mm, and the value obtained by dividing by the adhesion area was determined as epoxy adhesive strength. did. The results are shown in Table 2 below.

Claims (7)

The following general formula (1)

Wherein n is 0 to 2, Y ¹ represents a halogen atom, Y ² represents a hydrogen atom or a halogen atom, R ¹ represents a hydrogen atom, an alkyl group having 1 to 3 carbon atoms, or a cyclohexyl group; R ² represents an alkylene group having 3 to 5 carbon atoms, and X represents a hydrogen atom or an alkali metal atom.), An aprotic polar solvent, a polyhalo, An aromatic compound and (i) an alkali metal sulfide, or (ii) an alkali metal hydrosulfide and an alkali metal hydroxide are mixed, and the carboxyalkylamino group is mixed in the aprotic polar solvent. A containing compound, a polyhaloaromatic compound, and (i) an alkali metal sulfide, or (ii) an alkali metal hydrosulfide and an alkali metal hydroxide, and A polymerization step (a) for obtaining a crude reaction mixture comprising a polyarylene sulfide resin, an alkali metal-containing inorganic salt, the carboxyalkylamino group-containing compound and an aprotic polar solvent;
A solid-liquid separation step (a) for obtaining a reaction mixture containing a polyarylene sulfide resin, an alkali metal-containing inorganic salt and the carboxyalkylamino group-containing compound by solid-liquid separation of the aprotic polar solvent from the crude reaction mixture;
A purification step (a) in which the reaction mixture obtained in the solid-liquid separation step is brought into contact with water, the polyarylene sulfide resin is separated by filtration, and the polyarylene sulfide resin is recovered;
A process for producing a polyarylene sulfide resin, comprising: The ratio of aprotic polar solvent in the said polymerization process (a) is the range of 1.0-6.0 mol with respect to 1 mol of sulfur atoms in an alkali metal sulfide or an alkali metal hydrosulfide. A process for producing a polyarylene sulfide resin. In the polymerization step (a), the ratio of the carboxyalkylamino group-containing compound is in the range of 0.5 to 10 mmol with respect to 1 mol of sulfur atom in the alkali metal sulfide or alkali metal hydrosulfide. A process for producing the polyarylene sulfide resin as described. In the said polymerization process (a), the alkaline aqueous solution containing a carboxyalkylamino group containing compound is manufactured through the following processes 1-5, The polyarylene sulfide resin of any one of Claims 1-3. Production method.
(1) Step 1 to adjust the aqueous solution containing A alkali metal-containing inorganic salt and carboxyalkyl amino group-containing compound to pH6.0 or less
(2) Step 2 of adding a water-insoluble solvent to the aqueous solution to separate the organic phase containing the carboxyalkylamino group-containing compound and the water-insoluble solvent and the water phase containing the alkali metal-containing inorganic salt
(3) Step 3 of removing the aqueous phase containing the separated alkali metal-containing inorganic salt and recovering the organic phase containing the carboxyalkylamino group-containing compound and a water-insoluble solvent
(4) An alkaline aqueous solution is added to the organic phase recovered in Step 3, and the water-insoluble solvent and the following general formula (2)

Wherein n is 0 to 2, Y ¹ represents a halogen atom, Y ² represents a hydrogen atom or a halogen atom, R ¹ represents a hydrogen atom, an alkyl group having 1 to 3 carbon atoms, or a cyclohexyl group; Step ² in which R ² is an alkylene group having 3 to 5 carbon atoms, and X ′ is an alkali metal atom.
(5) Step 5 of removing the separated water-insoluble solvent and recovering an alkaline aqueous solution containing the carboxyalkylamino group-containing compound   The method for producing a polyarylene sulfide resin according to claim 4, wherein the water-insoluble solvent is a long-chain aliphatic hydrocarbon, alicyclic hydrocarbon, aromatic hydrocarbon or halogenated hydrocarbon. In the step 1, the aqueous solution containing the alkali metal-containing inorganic salt and the carboxyalkylamino group-containing compound is:
In an organic polar solvent, a polyhaloaromatic compound and (i) an alkali metal sulfide or (ii) an alkali metal hydrosulfide and an alkali metal hydroxide are reacted to form a polyarylene sulfide resin and an alkali metal. A polymerization step (b) for obtaining a crude reaction mixture containing a containing inorganic salt, the carboxyalkylamino group-containing compound and the organic polar solvent;
A solid-liquid separation step (b) for solid-liquid separation of the organic polar solvent from the crude reaction mixture to obtain a reaction mixture containing a polyarylene sulfide resin, an alkali metal-containing inorganic salt, and the carboxyalkylamino group-containing compound;
The reaction mixture is brought into contact with water, the polyarylene sulfide resin is filtered off, and obtained through a purification step (b) for recovering an aqueous solution containing the alkali metal-containing inorganic salt and the carboxyalkylamino group-containing compound. A method for producing a polyarylene sulfide resin according to claim 4.   The method for producing a polyarylene sulfide resin according to any one of claims 1 to 6, wherein the aprotic polar solvent is an organic amide solvent.