JP2024013931A - Method for producing polyarylene sulfide resin - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide polyarylene sulfide (PAS) which is excellent in melting stability, and a method for producing the same.

SOLUTION: A method for producing a PAS resin includes the steps of: reacting a polyhalo aromatic compound with a sulfication agent in an organic polar solvent, and obtaining a crude reaction mixture containing at least a PAS resin, an alkali metal halide, a carboxyalkylamino group-containing compound and an organic polar solvent; cooling the crude reaction mixture to a range of 1-100°C; washing the crude reaction mixture with water in a range of 20-280°C, then removing a liquid phase component by solid liquid separation, and obtaining a mixture (A) containing at least water and a polyarylene sulfide resin; and adding a compound containing a metal element to the mixture (A) and washing the mixture with water in a range of 20-280°C, wherein the compound containing the metal element is a salt containing a sulfur atom and a metal atom forming a sulfide salt having a solubility product (Ksp) of 1.0×10^-10 or less.

SELECTED DRAWING: None

COPYRIGHT: (C)2024,JPO&INPIT

Description

The present invention relates to a method for producing polyarylene sulfide resin.

Polyarylene sulfide resin (hereinafter abbreviated as PAS resin), represented by polyphenylene sulfide resin (hereinafter abbreviated as PPS resin), has excellent chemical resistance etc. due to the crystallinity of the surface of the molded product. It is widely used in electrical and electronic parts, automobile parts, water heater parts, textiles, film applications, etc. However, PAS resins generally have poor melt stability, and when melt-molded in a high-temperature environment exceeding the melting point (approximately 280° C.), there is a problem in that the viscosity changes particularly during residence. Therefore, particularly in extrusion molding and the production of fibers and films where residence times tend to be long, improvement in melt stability is desired from the viewpoint of improving moldability and quality of the final product obtained.

For example, in Patent Document 1, a PAS block copolymer containing 1 to 99% by weight of PAS units and 99 to 1% by weight of polyorganosiloxane units and a PAS resin with excellent melt retention stability are blended with polysiloxane. Compositions are disclosed. Furthermore, Patent Document 2 discloses a PAS resin composition in which an organic nickel compound is melt-mixed. However, these essential components that improve melt stability may limit other components that can be blended and the properties of the resulting resin composition. Therefore, a method for improving the melt stability of the PAS resin itself has been sought.

JP2018-53118A JP2018-188610A

Therefore, the problem to be solved by the present invention is to provide a method for producing a PAS resin that suppresses changes in the viscosity of the PAS resin during melt processing and has excellent melt stability.

As a result of various studies, the inventors of the present application discovered that a PAS resin with excellent melt stability can be obtained by adding a compound containing a specific metal in a specific cleaning process of the PAS resin, The present invention has now been completed.

That is, the present invention allows a polyhaloaromatic compound to react with (i) an alkali metal sulfide, or (ii) an alkali metal hydrosulfide and an alkali metal hydroxide, in an organic polar solvent, A crude reaction mixture containing at least a PAS resin, an alkali metal halide, a compound (1) represented by the following structural formula (1) (hereinafter sometimes abbreviated as a carboxyalkylamino group-containing compound), and an organic polar solvent. Obtaining step (1);
Step (2) of cooling the crude reaction mixture to a range of 1 to 100°C;
After washing the crude reaction mixture with water in the range of 20 to 280 ° C., removing the liquid phase component by solid-liquid separation to obtain a mixture (A) containing at least water and PAS resin (3);
a step (4) of adding a compound containing a metal element to the mixture (A) and washing with water at a temperature of 20 to 280°C, and
The present invention relates to a method for producing a PAS resin, wherein the metal salt is a salt containing a metal atom that forms a sulfide salt with a solubility product (Ksp) of 1.0×10 ⁻¹⁰ or less with a sulfur atom.

（式中、Ａｒはハロゲン原子を有するアリール基であり、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。）

(In the formula, Ar is an aryl group having a halogen atom, R ¹ represents a hydrogen atom, an alkyl group having 1 to 3 carbon atoms, or a cyclohexyl group, and R ² represents an alkylene group having 3 to 5 carbon atoms, (X represents a hydrogen atom or an alkali metal atom.)

According to the present invention, it is possible to provide a method for producing a PAS resin with excellent melt stability.

Hereinafter, one embodiment of the method for producing a PAS resin of the present invention will be illustrated and described.

The method for producing PAS resin of the present invention includes:
A polyhaloaromatic compound and (i) an alkali metal sulfide, or (ii) an alkali metal hydrosulfide and an alkali metal hydroxide are reacted in an organic polar solvent to form at least a PAS resin, an alkali Step (1) of obtaining a crude reaction mixture containing a metal halide, a carboxyalkylamino group-containing compound, and an organic polar solvent;
Step (2) of cooling the crude reaction mixture to a range of 1 to 100°C;
After washing the crude reaction mixture with water in the range of 20 to 280 ° C., removing the liquid phase component by solid-liquid separation to obtain a mixture (A) containing at least water and PAS resin (3);
a step (4) of adding a compound containing a metal element to the mixture (A) and washing with water at a temperature of 20 to 280°C, and
The method for producing a PAS resin is characterized in that the metal salt is a salt containing a metal atom that forms a sulfide salt with a solubility product (Ksp) of 1.0×10 ^-10 or less with a sulfur atom. The details will be explained below.

<Step (1)>
Step (1) involves polymerizing at least a polyhaloaromatic compound and (i) an alkali metal sulfide, or (ii) an alkali metal hydrosulfide and an alkali metal hydroxide in an organic polar solvent. This is a step of reacting to obtain a crude reaction mixture containing a PAS resin, an alkali metal halide, a carboxyalkylamino group-containing compound, and an organic polar solvent.

Here, in the present invention, the polyhaloaromatic compound is, for example, a halogenated aromatic compound having two or more halogen atoms directly bonded to an aromatic ring, and specifically, p-dichlorobenzene, o -Dichlorobenzene, m-dichlorobenzene, trichlorobenzene, tetrachlorobenzene, dibromobenzene, diiodobenzene, tribromobenzene, dibromnaphthalene, triiodobenzene, dichlorodiphenylbenzene, dibromodiphenylbenzene, dichlor Dihaloaromatic compounds such as benzophenone, dibrombenzophenone, dichlorodiphenyl ether, dibromodiphenyl ether, dichlordiphenyl sulfide, dibromodiphenylsulfide, dichlorbiphenyl, dibrombiphenyl, and mixtures thereof are mentioned, and these compounds can be blocked. May be copolymerized. Among these, preferred are dihalogenated benzenes, and particularly preferred are those containing 80 mol% or more of p-dichlorobenzene. Further, in order to increase the viscosity of the PAS resin by creating a branched structure, a polyhaloaromatic compound having three 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, and 1,4,6-trichloronaphthalene. Furthermore, polyhaloaromatic compounds having functional groups with active hydrogen such as amino groups, thiol groups, and hydroxyl groups can be mentioned, and specifically, 2,6-dichloroaniline, 2,5-dichloroaniline, etc. , 2,4-dichloroaniline, dihaloanilines such as 2,3-dichloroaniline; 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 include compounds in which the amino group is replaced with a thiol group or a hydroxyl group in a mixture thereof. In addition, active hydrogen-containing polyhaloaromatic compounds in which the hydrogen atom bonded to the carbon atom forming the aromatic ring in these active hydrogen-containing polyhaloaromatic compounds are substituted with other inert groups, for example, hydrocarbon groups such as alkyl groups. Aromatic compounds can also be used.

Among these various active hydrogen-containing polyhaloaromatic compounds, active hydrogen-containing dihaloaromatic compounds are preferred, and dichloroaniline is particularly preferred.

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

Further, in the present invention, an alkali metal sulfide, an alkali hydrosulfide, and an alkali metal hydroxide (hereinafter sometimes referred to as a sulfidating agent) are used as raw materials.

In the present invention, the alkali metal sulfide includes lithium sulfide, sodium sulfide, rubidium sulfide, cesium sulfide, and mixtures thereof. Such alkali metal sulfides can be used as hydrates or aqueous mixtures or as anhydrides. Moreover, an alkali metal sulfide can also be derived by a reaction between an alkali metal hydrosulfide and an alkali metal hydroxide. Note that a small amount of alkali metal hydroxide may be added in order to react with alkali metal hydrosulfide and alkali metal thiosulfate, which are usually present in a small amount in the alkali metal sulfide.

Further, the alkali metal hydrosulfide includes lithium hydrogen sulfide, sodium hydrogen sulfide, rubidium hydrogen sulfide, cesium hydrogen sulfide, and mixtures thereof. Such alkali metal hydrosulfides can be used as hydrates or aqueous mixtures or as anhydrides.

Further, the alkali metal hydrosulfide is used together with an alkali metal hydroxide. Examples of the alkali metal hydroxide include lithium hydroxide, sodium hydroxide, potassium hydroxide, rubidium hydroxide, cesium hydroxide, etc. Each of these may be used alone, or two or more types may be used in combination. It may also be used as Among these, lithium hydroxide, sodium hydroxide, and potassium hydroxide are preferred because they are easily available, and sodium hydroxide is particularly preferred.

The method for producing PAS resin of the present invention can also use a hydrous sulfidating agent as a raw material. In that case, the PAS resin is It is preferable to subject it to a polymerization reaction. In addition, when the amount of the aprotic polar solvent charged is small, for example, when it is less than 1 mol per 1 mol of sulfur atoms of the sulfidating agent, in the presence of the polyhaloaromatic compound, the water-containing sulfidating agent and the non-protic polar solvent are It is preferable to dehydrate the protic polar solvent.

The dehydration step of the hydrous sulfidating agent is performed by adding at least an aprotic polar solvent and a hydrous alkali metal sulfide or hydrous alkali hydrosulfide and alkali metal hydroxide as the hydrous sulfidating agent to a reaction vessel equipped with a distillation apparatus. Water is removed by distillation by heating to a temperature at which water is removed azeotropically, specifically in the range of 300°C or lower, preferably in the range of 80 to 220°C, more preferably in the range of 100 to 200°C. This is done by discharging it out of the system. In the dehydration step, dehydration is performed until the amount of water in the system performing the polymerization reaction becomes 5 mol or less, more preferably in the range of 0.01 to 2.0 mol, per 1 mol of sulfur atoms of the sulfidating agent. It is preferable.

In the present invention, examples of organic polar solvents include formamide, acetamide, N-methylformamide, N,N-dimethylacetamide, tetramethylurea, N-methyl-2-pyrrolidone, 2-pyrrolidone, N-methyl-ε-caprolactam. , ε-caprolactam, hexamethylphosphoramide, N-dimethylpropylene urea, amides such as 1,3-dimethyl-2-imidazolidinonic acid, urea and lactams; sulfolanes such as sulfolane and dimethylsulfolane; benzonitrile, etc. nitriles; ketones such as methylphenylketone and mixtures thereof; among these, N-methyl-2-pyrrolidone, 2-pyrrolidone, N-methyl-ε-caprolactam, ε-caprolactam, hexamethyl Amides having an aliphatic cyclic structure such as phosphoramide, N-dimethylpropylene urea, and 1,3-dimethyl-2-imidazolidinonic acid are preferred, and N-methyl-2-pyrrolidone is more preferred.

The polymerization reaction of the PAS resin in the PAS polymerization step involves reacting the alkali metal sulfide as a sulfidating agent with a polyhaloaromatic compound in the presence of these organic polar solvents. Alternatively, in the polymerization reaction of the PAS resin, the alkali metal hydrosulfide and alkali metal hydroxide as a sulfidizing agent are reacted with a polyhaloaromatic compound in the presence of these organic polar solvents. Polymerization conditions generally range from 200 to 330° C. and pressure should be such as to maintain the polymerization solvent and monomer polyhaloaromatic substantially in the liquid phase, generally 0. The pressure is selected from the range of 1 to 20 MPa, preferably 0.1 to 2 MPa. The amount of the polyhaloaromatic compound charged 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 in the range of 0.8 to 1.3 mol, per 1 mol of sulfur atom of the sulfidating agent. The amount is adjusted to be in the range of 0.9 to 1.1 mol. Further, the amount of the aprotic polar solvent to be charged is in the range of 1.0 to 6.0 mol, preferably in the range of 2.5 to 4.5 mol, per 1 mol of sulfur atom of the sulfidating agent. adjust. Note that the polymerization reaction is preferably carried out in the presence of a small amount of water, and the ratio is preferably adjusted as appropriate in consideration of the polymerization method, the molecular weight of the resulting polymer, and productivity. Specifically, dehydration is performed so that the amount is 2.0 mol or less, preferably 1.6 mol or less, per 1 mol of sulfur atoms of the sulfidating agent, and further dehydration is performed in the presence of a polyhaloaromatic compound. When performing the operation (for example, the method "5)" in the specific embodiment below), 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. The dehydration operation may be performed so that the

Specific embodiments of polymerizing the sulfidating agent and the polyhaloaromatic compound in the presence of the aprotic polar solvent described above include, for example,
1) A method using a polymerization aid such as an alkali metal carboxylate or lithium halide;
2) A method using a branching agent such as an aromatic polyhalogen compound,
3) A method of carrying out a polymerization reaction in the presence of a small amount of water, and then adding water and further polymerizing;
4) A method of cooling the gas phase portion of the reaction vessel during the reaction between the alkali metal sulfide and the aromatic dihalogen compound to condense a portion of the gas phase in the reaction vessel and refluxing it to a liquid phase;
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. After producing the slurry, a polar organic solvent such as NMP is further added and water is distilled off to perform dehydration. In the resulting slurry, a polyhaloaromatic compound, an alkali metal hydrosulfide, and an alkali metal salt of the hydrolyzate of an amide, urea, or lactam having an aliphatic cyclic structure are mixed in 1 mol of a polar organic solvent such as NMP. On the other hand, there is a method for producing a PAS resin which has as an essential production step a step of polymerizing the reaction in a state where the amount of water present in the reaction system is 0.02 mol or less.

In this way, by polymerizing a dihaloaromatic compound and (i) an alkali metal sulfide, or (ii) an alkali metal hydrosulfide and an alkali metal hydroxide in an organic polar solvent, As a product, a PAS resin is obtained, but in addition to that, a PAS oligomer is also produced as a by-product. The substances contained after the reaction may also include by-products such as an alkali metal-containing inorganic salt, a carboxyalkylamino group-containing compound, a terminal SH group-containing compound, unreacted raw materials, and water.

<Step (2)>
Step (2) is a step of cooling the crude reaction mixture to a temperature in the range of 1 to 100°C.

In this step, the temperature range after cooling the crude reaction mixture is preferably in the range of 1 to 100°C, more preferably in the range of 20 to 70°C. In this step, the method for cooling the crude reaction mixture is not particularly limited, and the container containing the crude reaction mixture can be cooled using a known method such as a cooling device containing cooling water, ice, or a refrigerant. The container for cooling may be either an open system or a closed system, and is not particularly limited, but cooling in a closed system is preferable from the viewpoint of improving productivity. The cooling rate is not particularly limited, but is preferably 3°C/min or more, more preferably 5°C/min, and preferably 50°C/min or less. In this range, the PAS resin is porous and precipitated, so that the efficiency of washing the PAS resin with water in the subsequent step is improved. Furthermore, the contact efficiency between the metal atom-containing compound and the PAS resin is improved, which is preferable.

<Step (3)>
Step (3) is a step of washing the crude reaction mixture with water at a temperature of 20 to 280°C, and then removing liquid phase components by solid-liquid separation to obtain a mixture (A) containing at least water and PAS resin. be.

The water washing method includes, for example, adding water to the reaction slurry, stirring it, and then filtering it using a filtration device. Examples include a method in which water is added again to form a slurry and then filtered, or a method in which water is added again and filtered while the water-containing cake is held in a filter. The amount of water added to the reaction slurry during water washing is preferably in the range of 2 to 10 times the theoretical yield of the PAS resin finally obtained, from the viewpoint of washing efficiency. It is preferable that the water washing is divided into 2 to 10 times, preferably 2 to 4 times.

The temperature of the water in washing is preferably in the range of 20 to 280°C, more preferably in the range of 50 to 100°C, and even more preferably in the range of 70 to 90°C. Within this range, unreacted raw materials (for example, the alkali metal sulfide, alkali metal hydrosulfide, etc. as the sulfidating agent) and byproducts (for example, the alkali metal halide and the carboxyalkylamino) contained in the crude reaction mixture are (group-containing compounds, etc.) are easily removed, and tend to be removed at less than a predetermined ratio relative to the PAS resin.

The amount of hot water used in water washing is preferably in the range of 1.5 to 10 times the mass of the PAS resin. When it is 1.5 times or more, the fluidity of the slurry is improved and uniform heating is performed, thereby improving the removal efficiency of the carboxyalkylamino group-containing compound. On the other hand, when it is 10 times or less, the amount of heat required to heat the slurry can be easily suppressed to an economical range, which is preferable. Further, hot water washing may be performed in two or more times using an amount of hot water in a range of 1.5 to 10 times the mass of the PAS resin.

By washing the crude reaction mixture with water in this step, at least a portion of the carboxyalkylamino group-containing compound is removed from the mixture (A). The mixture (A) that has undergone this step has a carboxyalkylamino group-containing compound content of 2000 ppm or less, more preferably 1000 ppm or less, still more preferably 500 ppm, based on the PAS resin contained in the mixture (A). The range is as follows.

The solid-liquid separation method used in this step includes, for example, a method of filtration using a filtration device, and a method of adding water to the filtration residue containing water (hereinafter abbreviated as "water-containing cake") obtained by the above-mentioned filtration. A method in which the water-containing cake is added to the slurry and then filtered, or a method in which water is added and filtered again while the water-containing cake is held in a filter, or after separation using a centrifugal separator such as a filtration or a screw decanter, the obtained Examples include a method in which water is directly added to the filtration residue to form a slurry, and then solid-liquid separation is repeatedly performed.

The mixture (A) obtained in this step is a mixture containing at least water and PAS resin. The water content of the mixture (A) is not particularly limited, but from the viewpoint of improving the fluidity and mixability of the slurry in subsequent steps, the water content in the mixture (A) is 1.5 parts by mass per 100 parts by mass of the PAS resin. The amount is preferably at least 3 parts by mass, more preferably at least 3 parts by mass. Further, from the viewpoint of cost and cleanability, it is preferably 10 parts by mass or less.

<Step (4)>
Step (4) is a step of adding a metal atom-containing compound to the mixture (A) and washing with water at a temperature in the range of 20 to 280°C.

The compound containing a metal atom used in this step is a compound that contains a metal atom and forms a sulfide salt with a sulfur atom having a solubility product (Ksp) of 1.0×10 ⁻¹⁰ or less, and the form of the compound is Examples include salts and complexes. The metal species contained in the compound is not particularly limited as long as it forms a sulfide salt with a solubility product (Ksp) of 1.0 × 10 ^-10 or less with a sulfur atom, but examples include silver, zinc, copper, manganese, Examples include tin, cadmium, mercury, iron, and nickel, with silver, zinc, and copper being particularly preferred. These compounds containing metal atoms can be used alone or in combination of one or more. Note that the solubility product (Ksp) of a sulfide salt is a value at 25° C. in an aqueous solution.

Further, the compound containing a metal atom used in this step is preferably one that dissolves in water when added to the mixture (A). When the compound containing a metal atom has solubility in water, sufficient affinity with the PAS resin contained in the mixture (A) is obtained, so that the resulting PAS resin has excellent melt stability.

The amount of the compound containing a metal atom added in this step is preferably 0.1 μmol/g or more, more preferably 1 μmol/g or more, and 10 μmol/g based on the PAS resin (theoretical yield) contained in the mixture (A). It is more preferable that the weight is more than g. Within this range, the resulting PAS resin has excellent melt stability.

In addition, in this step, from the viewpoint of suppressing the formation of hydroxide salts, oxide salts, complex salts, etc. by the compound containing the metal atom, an acid or a base is added to the mixture (A) in advance to adjust the pH. The step (4-1) can also include a step of adjusting. The acids and bases used in this case are not particularly limited as long as they do not impair the effects of the present invention, and known acids and bases can be used.

Regarding the adjustment range of the pH of the mixture (A) in this step, for example, the concentration of hydroxide ions contained in the mixture (A) and the metal ions added, or the concentration of the compound containing metal atoms in the mixture (A), It is preferable to adjust the solubility product (Ksp) of the hydroxide salt formed by the metal ion at the temperature at which the metal ion is added. For example, when adding a silver-containing compound to the mixture (A) at 25°C, the Ksp of silver hydroxide (AgOH) at 25°C is 1.9 × 10 ^-8 , so the hydroxide ion concentration and silver It is preferable to adjust the pH of the mixture (A) in advance based on the amount of the silver-containing compound added so that the product of ion concentrations is less than 1.9×10 ⁻⁸ . Specifically, the pH is preferably less than 11, for example. Similarly, when using a compound containing zinc, since the Ksp of zinc hydroxide (Zn(OH) ₂ ) at 25°C is 2.0 × 10 ^-17 , the square of the hydroxide ion and the zinc It is preferable to adjust the pH of the mixture (A) in advance based on the amount of the zinc-containing compound added so that the product of ion concentrations is less than 2.0×10 ⁻¹⁷ . Specifically, the pH is preferably less than 8, for example. Note that the pH in this step is a value measured at 25°C. Moreover, the solubility product (Ksp) of a hydroxide salt is a value at 25° C. in an aqueous solution. The unit of ion concentration is mol/L.

In this step, the mixture (A) to which the metal atom-containing compound is added is further washed with water. Washing with water can be performed in the same manner as step (3). The temperature of washing with water is preferably in the range of 20 to 280°C, and more preferably in the range of 50 to 100°C, from the viewpoint of good extraction efficiency of the alkali metal halide and sulfidating agent remaining in the resin. -90°C is more preferable from the viewpoint of balance between manufacturing cost and cleaning efficiency.

The mixture (A) containing PAS resin obtained through the above steps may then be used as a PAS resin powder by solid-liquid separation and drying, or after further washing treatment, solid-liquid separation and drying. It is also possible to prepare a powdered or granular PAS resin by performing this step. Furthermore, the obtained powdery or granular PAS resin can be heat-treated to form a crosslinked PAS resin.

The PAS resin obtained through the production method of the present invention described above has the following characteristics.

(melt stability)
The PAS resin obtained by the production method of the present invention has excellent melt stability. For example, the viscosity change rate α expressed by the following formula is in a range of 25% or less. In this range, it can be said that the resin increases and decreases in viscosity during melting, and has excellent melt stability. Further, resins with excellent melt stability can suppress changes in viscosity during melt molding and have excellent processability.
α=|{(V30-V6)/V6}|×100
(However, in the formula, V6 and V30 were measured using a flow tester at a temperature of 300°C, a load of 1.96 MPa, and an orifice with an orifice length and orifice diameter ratio of 10/1. (Represents the melt viscosity after holding for 6 minutes and 30 minutes.)

(weight loss)
Further, the PAS resin obtained by the production method of the present invention has a suppressed amount of gas generated during melting. For example, the weight loss expressed by the following formula is preferably 2.0 wt% or less, and more preferably 1.0 wt% or less. This range is preferable because deterioration of moldability and contamination of the surface of the molded product due to gas generated when the resin is melted are suppressed.
Weight loss = {(Weight value after heating at 150°C) - (Weight value after heating at 370°C)} ÷ (Weight value after heating at 150°C) x 100

The reason why such an effect is obtained is not necessarily clear, but it is presumed to be due to the following mechanism. In other words, when PAS resin is melted, it is thought that the polymer chain is cut due to nucleophilic attack derived from the terminal thiophenolate anion (S anion) of the PAS resin, resulting in thinning of the viscosity. We speculate that this nucleophilic attack is suppressed by adding high metal atoms. Specifically, it is thought that the nucleophilicity of the S anion decreases due to preferential formation of strong interactions between the S anion at the end of the polymer chain and the metal atom. Note that the above mechanism is only a speculation, and even if the effects of the present invention are achieved for other reasons, it is still within the technical scope of the present invention.

As in the past, the PAS resin obtained by the present invention can be blended with fillers and other resins, melt-kneaded, directly or once formed into pellets, and then processed by injection molding, extrusion molding, compression molding, blow molding, etc. By various melt processing methods, it is possible to make molded products with excellent heat resistance, moldability, dimensional stability, etc. However, in order to further improve performance such as strength, heat resistance, and dimensional stability, it is also possible to use it in combination with various fillers as long as the purpose of the present invention is not impaired. Examples of the filler include fibrous fillers and inorganic fillers. In addition, small amounts of mold release agents, colorants, heat stabilizers, ultraviolet stabilizers, foaming agents, rust preventives, flame retardants, lubricants, and cups may be used as additives during molding without departing from the purpose of the present invention. A ring agent can be included. Furthermore, the following synthetic resins and elastomers can be mixed and used in the same manner. These synthetic resins include polyester, polyamide, polyimide, polyetherimide, polycarbonate, polyphenylene ether, polysulfone, polyethersulfone, polyetheretherketone, polyetherketone, polyarylate, polyethylene, polypropylene, polytetrafluoroethylene, Examples of the elastomer include polydifluoroethylene, polystyrene, ABS resin, epoxy resin, silicone resin, phenol resin, urethane resin, and liquid crystal polymer, and examples of the elastomer include polyolefin rubber, fluorine rubber, and silicone rubber.

Molded products obtained by melt-molding the PAS resin of the present invention or a resin composition containing the same have excellent heat resistance, dimensional stability, etc., as well as PAS resins obtained by conventional methods. Electrical and electronic parts such as fixed molded products, automotive parts such as lamp reflectors and various electrical parts, interior materials for various buildings, aircraft, and automobiles, and precision parts such as OA equipment parts, camera parts, and clock parts. It can be widely used as injection molded and compression molded products, as well as extrusion molded and pultruded products such as fibers, films, sheets, and pipes.

EXAMPLES Hereinafter, the present invention will be specifically explained with reference to Examples, but the present invention is not limited only to these Examples.

<Evaluation>

(1) Evaluation of melt viscosity and melt stability Using Shimadzu's flow tester "CFT-500D", 300°C, load: 20 kgf/cm ² , L/D = 10 (mm) / 1 (mm) for 6 minutes Alternatively, the melt viscosity was measured after holding for 30 minutes. The melt stability was compared based on the viscosity change rate α. The viscosity change rate α (%) was defined as follows. When α is a smaller value, the viscosity change rate of the resin is small, indicating excellent melt stability. Further, V6 viscosity means the melt viscosity when held for 6 minutes, and V30 viscosity means the melt viscosity when held for 30 minutes.
α=|{(V30-V6)/V6}|×100

(2) Quantification of weight loss A 4.0000 g powder sample of PPS was weighed into an aluminum petri dish using a precision balance. After leaving the sample in a dryer set at 150° C. for 1 hour, the Petri dish was taken out, allowed to cool to room temperature, and then weighed. Next, the petri dish was left to stand in a dryer set at 370° C. for 1 hour, then taken out, allowed to cool to room temperature, and then weighed. The weight loss (wt%) of each sample was calculated from the following formula.
Weight loss = {(Weight value after heating at 150°C) - (Weight value after heating at 370°C)} ÷ (Weight value after heating at 150°C) x 100

<Examples 1 to 8, Comparative Examples 1 to 3>

Example (1-1) PPS production 580.12 g (3.5 g) of p-dichlorobenzene (hereinafter abbreviated as p-DCB) was placed in a 2 L autoclave equipped with stirring blades connected to a pressure gauge, thermometer, condenser, decanter, and rectification column. 95 mol), NMP 39.65 g (0.400 mol), 474.78 g of 47.23 mass% NaSH aqueous solution (4.00 mol as NaSH), and 322.31 g of 49.21 mass% NaOH aqueous solution (3.97 as NaOH) mol) was charged, and the temperature was raised to 173° C. over 5 hours under a nitrogen atmosphere while stirring to distill off 474.78 g of water, and then the pot was sealed. DCB distilled azeotropically during dehydration was separated in a decanter and returned to the pot as needed. After the dehydration was completed, the anhydrous sodium sulfide composition in the form of fine particles was dispersed in the p-DCB inside the pot. After the above dehydration step was completed, the internal temperature was cooled to 160°C, 825.95 kg (8.33 mol) of NMP was charged, and the temperature was raised to 185°C. When the pressure reached 0.00 MPa, the valve connected to the rectification column was opened, and the internal temperature was raised to 200° C. over 1 hour. At this time, cooling and valve opening were controlled so that the temperature at the outlet of the rectifying column was 110° C. or less. The distilled mixed vapor of p-DCB and water was condensed in a condenser and separated in a decanter, and the p-DCB was returned to the pot. The amount of distilled water was 3.11 g. The internal temperature was raised from 200°C to 230°C over 3 hours, stirred at 230°C for 3 hours, then heated to 250°C, and stirred for 1 hour. The final pressure was 0.30 MPa.

Example (1-2) Cooling and Recovery of Crude Reaction Mixture The autoclave was rapidly cooled down to room temperature (23°C) or lower with ice water, and the slurry after the reaction was completed was recovered.

Example (1-3) Warm water washing 100 g of the obtained slurry of 1.76 kg was taken out. 200 g of 70° C. ion-exchanged water was added to the slurry, stirred for 10 minutes, and then filtered, and 200 g of 70° C. ion-exchanged water was added to the filtered cake to wash the cake. 200 g of ion-exchanged water at 70°C and 2 mL of 1 wt% aqueous sodium hydroxide solution were added to the obtained water-containing cake, stirred for 10 minutes, and filtered. 200 g of ion-exchanged water at 70°C was added to the filtered cake to form a cake. Washed.

Example (1-4) Addition of heavy metal salt 200 g of 70° C. ion-exchanged water was added to the slurry. The pH of the slurry was 8.7. Further, 10 μmol of silver nitrate was added to 1 g of PPS resin, stirred for 10 minutes, and then filtered, and 200 g of ion-exchanged water at 70° C. was added to the filtered cake to wash the cake. 200 g of 70° C. ion-exchanged water was added to the obtained water-containing cake, stirred for 10 minutes, and filtered. 200 g of 70° C. ion-exchanged water was added to the filtered cake to wash the cake. Thereafter, it was dried at 120° C. for 4 hours to obtain PPS resin (1). The results are shown in Table 1.

Example (2)
A PPS resin (2) was obtained in the same manner as in Example (1) except that the amount of silver nitrate added was changed to 50 μmol per 1 g of PPS resin in Example (1-4). The results are shown in Table 1.

Example (3)
A PPS resin (3) was obtained in the same manner as in Example (1) except that the amount of silver nitrate added was changed to 100 μmol per 1 g of PPS resin in Example (1-4). The results are shown in Table 1.

Example (4)
In Example (1-4), PPS resin (4) was obtained in the same manner as in Example (1) except that 50 μmol of zinc nitrate was added to 1 g of PPS resin instead of silver nitrate. . The results are shown in Table 1.

Example (5)
PPS resin (5) was obtained in the same manner as in Example (1) except that 50 μmol of zinc chloride was added to 1 g of PPS resin instead of silver nitrate in Example (1-4). . The results are shown in Table 1.

Example (6)
Example (2-4) was carried out in the same manner as in Example (2), except that nitric acid was added to the slurry before adding silver nitrate to adjust the pH to 5.0, and PPS resin (6) was Obtained. The results are shown in Table 1.

Example (7)
Example (4-4) was carried out in the same manner as in Example (4), except that nitric acid was added to the slurry before adding zinc nitrate to adjust the pH to 5.0, and PPS resin (7) I got it. The results are shown in Table 1.

Example (8)
Example (6-4) was carried out in the same manner as in Example (6), except that 50 μmol of copper (II) nitrate was added to 1 g of PPS resin instead of silver nitrate, and PPS resin (8) I got it. The results are shown in Table 1.

Comparative example (1)
In Example (1-4), PPS resin (C1) was obtained in the same manner as in Example (1) except that 50 μmol of sodium nitrate was added to 1 g of PPS resin instead of silver nitrate. . The results are shown in Table 2.

Comparative example (2)
In Example (1-4), PPS resin (C2) was obtained in the same manner as in Example (1) except that 50 μmol of calcium nitrate was added to 1 g of PPS resin instead of silver nitrate. . The results are shown in Table 2.

Comparative example (3)
A PPS resin (C3) was obtained in the same manner as in Example (1) except that only the water-containing cake and ion-exchanged water were added in Example (1-4). The results are shown in Table 2.

From the above results, it was confirmed that the PAS resin obtained by the manufacturing method of the example has a smaller viscosity change rate and weight loss than the PAS resin of the comparative example, and is a PAS resin with excellent melt stability. It was shown that

Claims (5)

At least a polyarylene sulfide resin is produced by reacting a polyhaloaromatic compound with (i) an alkali metal sulfide, or (ii) an alkali metal hydrosulfide and an alkali metal hydroxide in an organic polar solvent. , a step (1) of obtaining a crude reaction mixture containing an alkali metal halide, a compound (1) represented by the following structural formula (1), and an organic polar solvent;
Step (2) of cooling the crude reaction mixture to a range of 1 to 100°C;
After washing the crude reaction mixture with water in the range of 20 to 280 ° C., removing the liquid phase component by solid-liquid separation to obtain a mixture (A) containing at least water and polyarylene sulfide resin (3);
a step (4) of adding a compound containing a metal element to the mixture (A) and washing with water at a temperature of 20 to 280°C, and
A method for producing a polyarylene sulfide resin, wherein the compound containing a metal element is a salt containing a metal atom that forms a sulfide salt with a solubility product (Ksp) of 1.0×10 ^-10 or less with a sulfur atom.

(In the formula, Ar is an aryl group having a halogen atom, R ¹ represents a hydrogen atom, an alkyl group having 1 to 3 carbon atoms, or a cyclohexyl group, and R ² represents an alkylene group having 3 to 5 carbon atoms, (X represents a hydrogen atom or an alkali metal atom.) The polyarylene sulfide resin according to claim 1, wherein the amount of the compound containing a metal element used in the step (4) is in a range of 0.1 μmol/g or more based on the polyarylene sulfide resin in the mixture (A). Method of manufacturing molded products. The method for producing a polyarylene sulfide resin according to claim 1 or 2, wherein the pH of the slurry before adding the compound containing a metal element to the mixture (A) in the step (4) is 11 or less. The method for producing a polyarylene sulfide resin according to claim 1 or 2, wherein the compound containing a metal element contains at least one metal selected from the group consisting of silver, zinc, and copper. The method for producing a polyarylene sulfide resin according to claim 1 or 2, wherein the proportion of the compound (1) represented by the following structural formula (1) contained is 2000 ppm or less.

(In the formula, Ar is an aryl group having a halogen atom, R ¹ represents a hydrogen atom, an alkyl group having 1 to 3 carbon atoms, or a cyclohexyl group, and R ² represents an alkylene group having 3 to 5 carbon atoms, (X represents a hydrogen atom or an alkali metal atom.)