Method for producing polyarylene sulfide resin

Abstract

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

Description

[Technical Field]

[0001] This invention relates to a method for producing polyarylene sulfide resin. [Background technology]

[0002] Polyarylene sulfide resins (hereinafter abbreviated as PAS resins), typified by polyphenylene sulfide resins (hereinafter abbreviated as PPS resins), have excellent chemical resistance due to the crystallinity of the molded product surface and are widely used in electrical and electronic components, automotive parts, water heater parts, textiles, films, and other applications. However, PAS resins generally have poor melt stability, and when melt-molded in high-temperature environments exceeding their melting point (approximately 280°C), there is a problem of large viscosity changes, especially during residence time. Therefore, especially in extrusion molding and the manufacture of textiles and films, where residence time tends to be long, there is a desire to improve melt stability from the viewpoint of improving moldability and the quality of the final product obtained.

[0003] For example, Patent Document 1 discloses 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 composition with excellent melt retention stability obtained by blending with polysiloxane. Patent Document 2 also discloses a PAS resin composition in which an organic nickel compound is melt-mixed. However, these had the potential to limit other components that could be blended and the properties of the resulting resin composition due to the essential components that improve melt stability. Therefore, there was a need for a method to improve the melt stability of the PAS resin itself. [Prior art documents] [Patent Documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 2018-53118 [Patent Document 2] Japanese Patent Publication No. 2018-188610 [Overview of the Initiative] [Problems that the invention aims to solve]

[0005] Therefore, the problem that the present invention aims to solve is to provide a method for producing PAS resin that suppresses viscosity changes during melt processing and has excellent melt stability. [Means for solving the problem]

[0006] As a result of various studies, the inventors of the present invention discovered that by adding a compound containing a specific metal during a specific cleaning process of PAS resin, a PAS resin with excellent melt stability can be obtained, thus completing the present invention.

[0007] In other words, the present invention provides a crude reaction mixture (1) comprising reacting a polyhalo-aromatic compound with (i) an alkali metal sulfide, or (ii) an alkali metal hydroxide and an alkali metal hydroxide in an organic polar solvent to obtain 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. The process (2) involves cooling the crude reaction mixture to a temperature range of 1 to 100°C, The crude reaction mixture is washed with water in the range of 20 to 280°C, and then the liquid phase component is removed by solid-liquid separation to obtain a mixture (A) containing at least water and PAS resin (3), The process includes a step (4) of adding a compound containing a metal element to the mixture (A) and washing it with water in the range of 20 to 280°C, and The aforementioned metal salt has a solubility product (Ksp) of 1.0 × 10⁻¹⁰ with sulfur atoms. -10 This invention relates to a method for producing PAS resin, which is a salt containing metal atoms that form the following sulfide salts.

[0008] [ka] (In the formula, Ar is an aryl group having a halogen atom, R 1R represents a hydrogen atom or an alkyl group or cyclohexyl group having 1 to 3 carbon atoms. 2 (where X represents an alkylene group with 3 to 5 carbon atoms, and X represents a hydrogen atom or an alkali metal atom.) [Effects of the Invention]

[0009] According to the present invention, it is possible to provide a method for producing PAS resin with excellent melt stability. [Modes for carrying out the invention]

[0010] The following describes an example embodiment of the method for producing the PAS resin of the present invention.

[0011] The method for producing PAS resin of the present invention is as follows: Step (1) involves reacting a polyhalo-aromatic compound with (i) an alkali metal sulfide, or (ii) an alkali metal hydroxide and an alkali metal hydroxide in an organic polar solvent to obtain a crude reaction mixture containing at least a PAS resin, an alkali metal halide, a carboxyalkylamino group-containing compound, and an organic polar solvent. The process (2) involves cooling the crude reaction mixture to a temperature range of 1 to 100°C, The crude reaction mixture is washed with water in the range of 20 to 280°C, and then the liquid phase component is removed by solid-liquid separation to obtain a mixture (A) containing at least water and PAS resin (3), The process includes a step (4) of adding a compound containing a metal element to the mixture (A) and washing it with water in the range of 20 to 280°C, and The aforementioned metal salt has a solubility product (Ksp) of 1.0 × 10⁻¹⁰ with sulfur atoms. -10 The present invention relates to a method for producing PAS resin, which is a salt containing metal atoms that form the following sulfide salts. Details are provided below.

[0012] <Process (1)> Step (1) is a step in which a polyhalo-aromatic compound and (i) an alkali metal sulfide, or (ii) an alkali metal hydroxide and an alkali metal hydroxide are polymerized in an organic polar solvent to obtain a crude reaction mixture containing PAS resin, an alkali metal halide, a carboxyalkylamino group-containing compound, and an organic polar solvent.

[0013] In this invention, the polyhalo-aromatic compound is, for example, a halogenated aromatic compound having two or more halogen atoms directly bonded to an aromatic ring. Specifically, examples include dihalo-aromatic compounds such as p-dichlorobenzene, o-dichlorobenzene, m-dichlorobenzene, trichlorobenzene, tetrachlorobenzene, dibrombenzene, diiodobenzene, tribrombenzene, dibromnaphthalene, triiodobenzene, dichlorodiphenylbenzene, dibromdiphenylbenzene, dichlorobenzophenone, dibrombenzophenone, dichlorodiphenyl ether, dibromdiphenyl ether, dichlorodiphenyl sulfide, dibromdiphenyl sulfide, dichlorobiphenyl, and dibrombiphenyl, as well as mixtures thereof. These compounds may be block copolymerized. Among these, dihalogenated benzenes are preferred, and those containing 80 mol% or more of p-dichlorobenzene are particularly preferred. Furthermore, in order to increase the viscosity of the PAS resin by creating a branched structure, polyhalo-aromatic compounds having three or more halogen substituents in one molecule may be used as branching agents as desired. Examples of such polyhalo-aromatic compounds include 1,2,4-trichlorobenzene, 1,3,5-trichlorobenzene, and 1,4,6-trichloronaphthalene. Furthermore, examples include polyhalo-aromatic compounds having functional groups with active hydrogens such as amino groups, thiol groups, and hydroxyl groups. Specifically, these include dihaloanilines such as 2,6-dichloroaniline, 2,5-dichloroaniline, 2,4-dichloroaniline, and 2,3-dichloroaniline; trihaloanilines such as 2,3,4-trichloroaniline, 2,3,5-trichloroaniline, 2,4,6-trichloroaniline, and 3,4,5-trichloroaniline; dihaloaminodiphenyl ethers such as 2,2'-diamino-4,4'-dichlorodiphenyl ether and 2,4'-diamino-2',4-dichlorodiphenyl ether, and compounds in which the amino group is replaced with a thiol group or a hydroxyl group in mixtures thereof.In addition, active hydrogen-containing polyhaloaromatic compounds in which the hydrogen atoms bonded to the carbon atoms forming the aromatic rings in these active hydrogen-containing polyhaloaromatic compounds are substituted with other inert groups, such as hydrocarbon groups such as alkyl groups, can also be used.

[0014] Among these various active hydrogen-containing polyhaloaromatic compounds, preferred are active hydrogen-containing dihaloaromatic compounds, and particularly preferred is dichloroaniline. <000009​​​​​​​​​​​​​Furthermore, the alkali metal hydrosulfides include lithium hydrogen sulfide, sodium hydrogen sulfide, rubidium hydrogen sulfide, cesium hydrogen sulfide, and mixtures thereof. Such alkali metal hydrosulfides can be used as hydrates, aqueous mixtures, or anhydrous products.

[0019] Furthermore, the alkali metal hydroxide is used together with an alkali metal hydroxide. Examples of alkali metal hydroxides include lithium hydroxide, sodium hydroxide, potassium hydroxide, rubidium hydroxide, and cesium hydroxide, which may be used individually or in combination of two or more. Among these, lithium hydroxide, sodium hydroxide, and potassium hydroxide are preferred due to their availability, with sodium hydroxide being particularly preferred.

[0020] The present invention's method for producing PAS resin can also use a hydrated sulfidating agent as a raw material. In this case, it is preferable to dehydrate the hydrated sulfidating agent in the presence of at least an aprotic polar solvent before subjecting it to the polymerization reaction of the PAS resin. Furthermore, if the amount of aprotic polar solvent charged is small, for example, less than 1 mole per mole of sulfur atoms in the sulfidating agent, it is preferable to dehydrate the hydrated sulfidating agent and the aprotic polar solvent in the presence of a polyhalo-aromatic compound.

[0021] The dehydration step of the hydrated sulfidating agent is carried out by charging at least an aprotic polar solvent and a hydrated alkali metal sulfide or hydrated alkaline aqueous sulfide and alkali metal hydroxide as the hydrated sulfidating agent into a reaction vessel equipped with a distillation apparatus, heating to a temperature at which water is removed by azeotropy, specifically in the range of 300°C or less, preferably in the range of 80 to 220°C, more preferably in the range of 100 to 200°C, and then discharging the water from the system by distillation. In the dehydration step, it is preferable to dehydrate until the amount of water in the system carrying out the polymerization reaction is 5 moles or less, more preferably in the range of 0.01 to 2.0 moles, per mole of sulfur atoms of the sulfidating agent.

[0022] In addition, examples of organic polar solvents in the present invention include amides, ureas and lactams such as formamide, acetamide, N-methylformamide, N,N-dimethylacetamide, tetramethylurea, N-methyl-2-pyrrolidone, 2-pyrrolidone, N-methyl-ε-caprolactam, ε-caprolactam, hexamethylphosphoramide, N-dimethylpropyleneurea, and 1,3-dimethyl-2-imidazolidinonic acid; sulfolanes such as sulfolane and dimethylsulfolane; nitriles such as benzonitrile; ketones such as methylphenyl ketone and mixtures thereof. Among these, amides having an aliphatic cyclic structure such as N-methyl-2-pyrrolidone, 2-pyrrolidone, N-methyl-ε-caprolactam, ε-caprolactam, hexamethylphosphoramide, N-dimethylpropyleneurea, and 1,3-dimethyl-2-imidazolidinonic acid are preferred, and N-methyl-2-pyrrolidone is even more preferred.

[0023] In the PAS polymerization process, the polymerization reaction of the PAS resin involves reacting the alkali metal sulfide and the polyhalo-aromatic compound as sulfidating agents in the presence of these organic polar solvents. Alternatively, the polymerization reaction of the PAS resin involves reacting the alkali metal hydroxide and alkali metal hydroxide as sulfidating agents with the polyhalo-aromatic compound in the presence of these organic polar solvents. The polymerization conditions are generally in the temperature range of 200 to 330°C, and the pressure should be in a range that substantially maintains the polymerization solvent and the polyhalo-aromatic compound, which is the polymerization monomer, in the liquid phase, and is generally selected from the range of 0.1 to 20 MPa, preferably from 0.1 to 2 MPa. The amount of polyhalo-aromatic compound to be charged is prepared in the range of 0.2 moles to 5.0 moles, preferably from 0.8 to 1.3 moles, and more preferably from 0.9 to 1.1 moles, per mole of sulfur atoms of the sulfidating agent. Furthermore, the amount of aprotic polar solvent charged is adjusted to be in the range of 1.0 to 6.0 moles, preferably 2.5 to 4.5 moles, per mole of sulfur atoms of the sulfidating agent. The polymerization reaction is preferably carried out in the presence of a small amount of water, and the proportion is preferably adjusted as appropriate in consideration of the polymerization method, the molecular weight of the obtained polymer, and productivity. Specifically, the dehydration operation is carried out so that the amount of water is in the range of 2.0 moles or less, preferably 1.6 moles or less, per mole of sulfur atoms of the sulfidating agent. However, if the dehydration operation is carried out in the presence of a polyhalo-aromatic compound (for example, the method in "5)" in the specific embodiment below), the amount of water should be in the range of 0.9 moles or less, preferably 0.05 to 0.3 moles, more preferably 0.01 to 0.02 moles or less.

[0024] Specific embodiments of polymerizing a sulfidating agent and a polyhalo-aromatic compound in the presence of the aforementioned aprotic polar solvent include, for example, 1) A method using polymerization aids such as alkali metal carboxylates or lithium halides. 2) A method using branching agents such as aromatic polyhalogen compounds, 3) A method in which polymerization is carried out in the presence of a small amount of water, and then water is added to further polymerize the molecule. 4) A method in which, during the reaction of an alkali metal sulfide with an aromatic dihalogen compound, the gas phase portion of the reaction vessel is cooled to condense a portion of the gas phase inside the reaction vessel and reflux it into the liquid phase. 5) A method for producing PAS resin, which has the following essential manufacturing steps: 1) Reacting an alkali metal sulfide, or a hydrated alkali metal hydroxide and alkali metal hydroxide, with an amide, urea, or lactam having an aliphatic cyclic structure in the presence of a polyhalo-aromatic compound, while dehydrating, to produce a slurry containing a solid alkali metal sulfide; 2) After producing the slurry, adding a polar organic solvent such as NMP and removing the water by distillation to dehydrate the slurry; and 3) Reacting a polyhalo-aromatic compound, an alkali metal hydroxide, and an alkali metal salt of the hydrolysis product of the amide, urea, or lactam having an aliphatic cyclic structure in the slurry obtained through the dehydration step, at a rate of 0.02 moles or less of water present in the reaction system per mole of a polar organic solvent such as NMP, to carry out polymerization.

[0025] Thus, by polymerizing a dihalo-aromatic compound with (i) an alkali metal sulfide, or (ii) an alkali metal hydroxide and an alkali metal hydroxide in an organic polar solvent, PAS resin is obtained as a product, but PAS oligomers are also produced as by-products. Substances contained after the reaction may also include by-products such as alkali metal-containing inorganic salts, carboxyalkylamino group-containing compounds, terminal SH group-containing compounds, unreacted raw materials, and water.

[0026] <Process (2)> Step (2) is a step of cooling the crude reaction mixture to a temperature range of 1 to 100°C.

[0027] In this step, the temperature range of the crude reaction mixture after cooling is preferably 1 to 100°C, more preferably 20 to 70°C or lower. In this step, the method of cooling the crude reaction mixture is not particularly limited, and the container containing the crude reaction mixture can be cooled using known methods such as cooling water, ice, or a cooling device containing a refrigerant. The container used for cooling may be 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. Furthermore, there are no particular restrictions on the cooling rate, but it is preferably in the range of 3°C / min or more, more preferably 5°C / min, and more preferably 50°C / min or lower. In this range, the PAS resin precipitates with a porous structure, which improves the water washing efficiency of the PAS resin in subsequent steps. In addition, it is preferable that the contact efficiency between the compound containing metal atoms and the PAS resin is improved.

[0028] <Process (3)> Step (3) is a step in which the crude reaction mixture is washed with water in the range of 20 to 280°C, and then the liquid phase component is removed by solid-liquid separation to obtain a mixture (A) containing at least water and PAS resin.

[0029] Methods of washing with water include, for example, adding water to the reaction slurry, stirring, and then filtering using a filtration device; adding water again to the water-containing filtration residue obtained by the above filtration (hereinafter abbreviated as "water-containing cake") to form a slurry and then filtering; or adding water again while the water-containing cake is held in the filter and then filtering. The amount of water added to the reaction slurry during washing is preferably in the range of 2 to 10 times the theoretical yield of the final PAS resin obtained, which is preferable from the viewpoint of washing efficiency, and it is preferable to divide the above amount of water into 2 to 10 times, preferably 2 to 4 times, and subject it to washing.

[0030] The water temperature during 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 (e.g., alkali metal sulfides and alkali metal hydroxides as sulfidating agents) and by-products (e.g., alkali metal halides and carboxyalkylamino group-containing compounds) contained in the crude reaction mixture are easily removed and tend to be removed to less than a predetermined proportion relative to the PAS resin.

[0031] The amount of hot water used for washing is preferably in the range of 1.5 to 10 times the mass of the PAS resin. If it is 1.5 times or more, the fluidity of the slurry is improved and uniform heating is achieved, thereby improving the efficiency of removing the carboxyalkylamino group-containing compound. On the other hand, if it is 10 times or less, the amount of heat required to heat the slurry is easily suppressed to an economical range, which is preferable. Alternatively, the hot water washing may be performed in two or more stages using an amount of hot water in the range of 1.5 to 10 times the mass of the PAS resin.

[0032] In this step, the crude reaction mixture is washed with water to remove at least a portion of the carboxyalkylamino group-containing compound from the mixture (A). The mixture (A) after this step has a carboxyalkylamino group-containing compound content of 2000 ppm or less, more preferably 1000 ppm or less, and even more preferably 500 ppm or less, relative to the PAS resin contained in the mixture (A).

[0033] Examples of solid-liquid separation methods used in this process include filtration using a filtration device, adding water again to the water-containing filtration residue obtained by the above filtration (hereinafter abbreviated as "water-containing cake") to form a slurry and then filtering, adding water again while the water-containing cake is held in the filter and filtering, and separating using filtration or a centrifuge such as a screw decanter, then adding water directly to the obtained filtration residue to form a slurry, and then repeatedly performing solid-liquid separation.

[0034] The mixture (A) obtained in this process 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 processes, it is preferable that the water content in the mixture (A) be 1.5 parts by mass or more, and more preferably 3 parts by mass or more, per 100 parts by mass of PAS resin. Furthermore, from the viewpoint of cost and washability, it is preferable to have 10 parts by mass or less.

[0035] <Process (4)> Step (4) is a step in which a compound containing metal atoms is added to the mixture (A) and washed with water in the range of 20 to 280°C.

[0036] The metal atom-containing compound used in this process contains a metal atom and has a solubility product (Ksp) of 1.0 × 10¹⁶ with sulfur atoms. -10 The following compounds form sulfide salts, and these compounds can take the form of salts or complexes. The solubility product (Ksp) of the sulfur atom is 1.0 × 10⁻⁶. -10 The metal species included in the compound is not particularly limited as long as it forms the following sulfide salts, but examples include silver, zinc, copper, manganese, tin, cadmium, mercury, iron, nickel, etc., with silver, zinc, and copper being particularly preferred. Compounds containing these metal atoms can be used individually or in combination of one or more. The solubility product (Ksp) of the sulfide salt is the value at 25°C in aqueous solution.

[0037] Furthermore, the metal atom-containing compound used in this process is preferably one that dissolves in water when added to the mixture (A). When the metal atom-containing compound is soluble in water, sufficient affinity is obtained with the PAS resin contained in the mixture (A), resulting in a PAS resin with excellent melt stability.

[0038] The amount of the metal atom-containing compound added in this process is preferably 0.1 μmol / g or more, more preferably 1 μmol / g or more, and even more preferably 10 μmol / g or more, relative to the PAS resin (theoretical yield) contained in the mixture (A). Within this range, the resulting PAS resin exhibits excellent melt stability.

[0039] Also, 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, a step of adjusting the pH by adding an acid or a base to the mixture (A) in advance can also be included as step (4-1). Regarding the acid or base used in this case, it is not particularly limited as long as the effects of the present invention are not impaired, and known ones can be used.

[0040] Regarding the adjustment range of the pH of the mixture (A) in this step, for example, it is preferable to adjust it in consideration of the concentration of hydroxide ions and the metal ions to be added in the mixture (A), or the solubility product (Ksp) of the hydroxide salt formed by the metal ions at the temperature at which the compound containing the metal atom is added to the mixture (A). 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 Therefore, it is preferable to adjust the pH of the mixture (A) in advance based on the addition amount of the silver-containing compound so that the product of the hydroxide ion concentration and the silver ion concentration is less than 1.9×10 -8 Specifically, for example, a pH of less than 11 is preferable. Similarly, when using a zinc-containing compound, since the Ksp of zinc hydroxide (Zn(OH)2) at 25°C is 2.0×10 -17 Therefore, it is preferable to adjust the pH of the mixture (A) in advance based on the addition amount of the zinc-containing compound so that the product of the square of the hydroxide ion concentration and the zinc ion concentration is less than 2.0×10 -17 Specifically, for example, a pH of less than 8 is preferable. The pH in this step is the value measured at 25°C. Also, the solubility product (Ksp) of the hydroxide salt is the value at 25°C in an aqueous solution. The unit of the ion concentration is mol / L.

[0041] In this step, the mixture (A) to which the compound containing metal atoms has been added is further washed with water. The washing can be carried out in the same manner as in step (3). The washing temperature is preferably in the range of 20 to 280°C, more preferably in the range of 50 to 100°C from the viewpoint of good extraction efficiency of alkali metal halides and sulfidating agents remaining in the resin, and more preferably in the range of 70 to 90°C from the viewpoint of balancing manufacturing cost and washing efficiency.

[0042] The mixture (A) containing PAS resin obtained through the above process may then be used as PAS resin powder after solid-liquid separation and drying, or it may be further washed, followed by solid-liquid separation and drying to prepare it as powdered or granular PAS resin. Furthermore, the obtained powdered or granular PAS resin can be heat-treated to produce crosslinked PAS resin.

[0043] The PAS resin obtained through the manufacturing method of the present invention described above has the following characteristics.

[0044] (Melting stability) The PAS resin obtained by the manufacturing method of the present invention exhibits excellent melt stability. For example, the viscosity change rate α, expressed by the following formula, is in the range of 25% or less. Within this range, the resin can be said to have suppressed viscosity increase or decrease during melting, and thus exhibits excellent melt stability. Furthermore, resins with excellent melt stability can suppress viscosity changes during melt molding, and thus exhibit excellent processability. α = |{(V30-V6) / V6}| × 100 (However, in the formula, V6 and V30 represent the melt viscosity after holding for 6 minutes and 30 minutes, respectively, using a flow tester at a temperature of 300°C, a load of 1.96 MPa, and an orifice with an orifice length-to-orifice diameter ratio of 10 / 1.)

[0045] (Weight loss) Furthermore, the PAS resin obtained by the manufacturing method of the present invention has a suppressed amount of gas generated during melting. For example, a 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 it suppresses deterioration of moldability and contamination of the molded product surface caused by gas generated when the resin is melted. Weight loss = {(Weighing value after heating at 150°C) - (Weighing value after heating at 370°C)} ÷ (Weighing value after heating at 150°C) × 100

[0046] The reason for these effects is not entirely clear, but it is presumed to be due to the following mechanism. Specifically, it is thought that when PAS resin melts, the polymer chains are cleaved by nucleophilic attack originating from the terminal thiophenolate anions (S anions) of the PAS resin, leading to a decrease in viscosity. It is presumed that this nucleophilic attack is suppressed by adding metal atoms with high affinity for sulfur atoms. More specifically, it is thought that a strong interaction is preferentially formed between the S anions at the ends of the polymer chains and the metal atoms, thereby reducing the nucleophilicity of the S anions. It should be noted that the above mechanism is merely a hypothesis, and even if the effects of the present invention are achieved for other reasons, they are still within the technical scope of the present invention.

[0047] The PAS resin obtained by the present invention can be molded into a molded product with excellent heat resistance, moldability, and dimensional stability by melt-kneading it with fillers or other resins, as in the conventional method, and then directly or after being molded into pellets, using various melt processing methods such as injection molding, extrusion molding, compression molding, and blow molding. 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, within the limits that do not impair the objectives of the present invention. Examples of fillers include fibrous fillers and inorganic fillers. Furthermore, small amounts of release agents, colorants, heat stabilizers, UV stabilizers, foaming agents, rust inhibitors, flame retardants, lubricants, and coupling agents can be included as additives during the molding process, within the limits that do not deviate from the objectives of the present invention. In addition, the following synthetic resins and elastomers can be mixed and used in the same manner. Examples of these synthetic resins include polyester, polyamide, polyimide, polyetherimide, polycarbonate, polyphenylene ether, polysulfone, polyethersulfone, polyetheretherketone, polyetherketone, polyarylate, polyethylene, polypropylene, polytetrafluoroethylene, polydifluoroethylene, polystyrene, ABS resin, epoxy resin, silicone resin, phenolic resin, urethane resin, and liquid crystal polymer. Examples of elastomers include polyolefin rubber, fluorine rubber, and silicone rubber.

[0048] Molded articles obtained by melt-molding the PAS resin or resin composition containing the same of the present invention have excellent heat resistance, dimensional stability, etc., similar to PAS resin obtained by conventional methods. Therefore, they can be widely used as, for example, electrical and electronic components such as connectors, printed circuit boards, and encapsulated molded products; automotive parts such as lamp reflectors and various electrical components; interior materials for various buildings, aircraft, and automobiles; injection-molded and compression-molded products such as precision parts such as OA equipment parts, camera parts, and watch parts; or extruded and pultruded products such as fibers, films, sheets, and pipes. [Examples]

[0049] The present invention will be described in detail below with reference to examples, but the present invention is not limited to these examples.

[0050] <Rating>

[0051] (1) Evaluation of melt viscosity and melt stability Using a Shimadzu CFT-500D flow tester, the temperature was set to 300°C and the load to 20 kgf / cm². 2 The melt viscosity was measured after holding for 6 minutes or 30 minutes at a ratio of L / D = 10(mm) / 1(mm). Melt stability was compared using the viscosity change rate α. The viscosity change rate α (%) was defined as follows: A smaller value of α indicates a smaller viscosity change rate of the resin and superior melt stability. Furthermore, V6 viscosity refers to the melt viscosity after holding for 6 minutes, and V30 viscosity refers to the melt viscosity after holding for 30 minutes. α = |{(V30-V6) / V6}| × 100

[0052] (2) Determination of weight loss A 4.0000g sample of PPS powder was weighed into an aluminum petri dish using a precision balance. The sample was left to stand in a drying oven set to 150°C for 1 hour, then the petri dish was removed, allowed to cool to room temperature, and weighed again. Next, the same petri dish was left to stand in a drying oven set to 370°C for 1 hour, then the petri dish was removed, allowed to cool to room temperature, and weighed again. The weight loss (wt%) of each sample was calculated using the following formula. Weight loss = {(Weighing value after heating at 150°C) - (Weighing value after heating at 370°C)} ÷ (Weighing value after heating at 150°C) × 100

[0053] <Examples 1-8, Comparative Examples 1-3>

[0054] Example (1-1) PPS Manufacturing 580.12 g (3.95 mol) of p-dichlorobenzene (hereinafter abbreviated as p-DCB), 39.65 g (0.400 mol) of NMP, 474.78 g (4.00 mol) of 47.23 mass% NaSH aqueous solution, and 322.31 g (3.97 mol) of 49.21 mass% NaOH aqueous solution were charged into a 2 L autoclave equipped with a stirring blade and connected to a pressure gauge, thermometer, condenser, decanter, and rectification column. The mixture was heated to 173°C over 5 hours under a nitrogen atmosphere while stirring, and 474.78 g of water was distilled off, after which the autoclave was sealed. DCB distilled off by azeotrope during dehydration was separated in the decanter and returned to the autoclave as needed. After dehydration, the contents of the autoclave were in a state where particulate anhydrous sodium sulfide composition was dispersed in p-DCB. After the above dehydration process 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. During this time, the temperature at the outlet of the rectification column was controlled by cooling and valve opening to keep it below 110°C. The distilled p-DCB and water mixture was condensed in a condenser, separated in a decanter, and the p-DCB was returned to the boiler. The amount of water distilled 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 raised to 250°C and stirred for 1 hour. The final pressure was 0.30 MPa.

[0055] Examples (1-2) Cooling and recovery of crude reaction mixture The autoclave was rapidly cooled to below room temperature (23°C) using ice water, and the slurry was recovered after the reaction was complete.

[0056] Examples (1-3) Hot water washing Of the 1.76 kg of slurry obtained, 100 g was set aside. 200 g of ion-exchanged water at 70°C was added to the slurry and stirred for 10 minutes, then filtered. After filtering, 200 g of ion-exchanged water at 70°C was added to the cake and the cake was washed. 200 g of ion-exchanged water at 70°C and 2 mL of 1 wt% sodium hydroxide aqueous solution were added to the resulting hydrated cake and stirred for 10 minutes, then filtered. After filtering, 200 g of ion-exchanged water at 70°C was added and the cake was washed.

[0057] Examples (1-4) Addition of heavy metal salts 200 g of ion-exchanged water at 70°C was added to the slurry. The pH of the slurry was 8.7. Furthermore, 10 μmol of silver nitrate was added per 1 g of PPS resin, and the mixture was stirred for 10 minutes. After filtration, 200 g of ion-exchanged water at 70°C was added to the filtered cake to wash it. 200 g of ion-exchanged water at 70°C was added to the resulting hydrated cake and stirred for 10 minutes. After filtration, 200 g of ion-exchanged water at 70°C was added to the filtered cake to wash it. The cake was then dried at 120°C for 4 hours to obtain PPS resin (1). The results are shown in Table 1.

[0058] Example (2) In Examples (1-4), the procedure was the same as in Example (1), except that the amount of silver nitrate added was changed to 50 μmol per 1 g of PPS resin, to obtain PPS resin (2). The results are shown in Table 1.

[0059] Example (3) In Examples (1-4), the procedure was the same as in Example (1), except that the amount of silver nitrate added was changed to 100 μmol per 1 g of PPS resin, to obtain PPS resin (3). The results are shown in Table 1.

[0060] Example (4) In Examples (1-4), the procedure was the same as in Example (1), except that 50 μmol of zinc nitrate was added per 1 g of PPS resin instead of silver nitrate, to obtain PPS resin (4). The results are shown in Table 1.

[0061] Example (5) In Examples (1-4), the procedure was the same as in Example (1), except that 50 μmol of zinc chloride was added per 1 g of PPS resin instead of silver nitrate, to obtain PPS resin (5). The results are shown in Table 1.

[0062] Example (6) In Example (2-4), the procedure was the same 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.

[0063] Example (7) In Example (4-4), the procedure was the same 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) was obtained. The results are shown in Table 1.

[0064] Example (8) In Example (6-4), the procedure was carried out in the same manner as in Example (6), except that 50 μmol of copper(II) nitrate was added per 1 g of PPS resin instead of silver nitrate, to obtain PPS resin (8). The results are shown in Table 1.

[0065] Comparative Example (1) In Examples (1-4), the procedure was the same as in Example (1), except that 50 μmol of sodium nitrate was added per 1 g of PPS resin instead of silver nitrate, to obtain PPS resin (C1). The results are shown in Table 2.

[0066] Comparative Example (2) In Examples (1-4), the procedure was the same as in Example (1), except that 50 μmol of calcium nitrate was added per 1 g of PPS resin instead of silver nitrate, to obtain PPS resin (C2). The results are shown in Table 2.

[0067] Comparative Example (3) In Examples (1-4), the procedure was the same as in Example (1), except that only a water-containing cake and deionized water were added, to obtain PPS resin (C3). The results are shown in Table 2.

[0068] [Table 1]

[0069] [Table 2]

[0070] From the above results, it was found that the PAS resin obtained by the manufacturing method of the example had a smaller viscosity change rate and weight loss compared to the PAS resin of the comparative example, indicating that it is a PAS resin with excellent melt stability.

Claims

1. Step (1) involves reacting a polyhalo-aromatic compound with (i) an alkali metal sulfide, or (ii) an alkali metal hydroxide and an alkali metal hydroxide in an organic polar solvent to obtain a crude reaction mixture containing at least a polyarylene sulfide resin, 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, The crude reaction mixture is washed with water in the range of 20 to 280°C, and then the liquid phase component is removed by solid-liquid separation to obtain a mixture (A) containing at least water and polyarylene sulfide resin (3), A method for producing polyarylene sulfide resin, comprising the steps of: (4) adding 0.1 μmol / g or more of a salt containing a metal atom selected from the group consisting of silver, zinc, and copper, and which forms a sulfide salt with a sulfur atom having a solubility product (Ksp) of 1.0 × 10⁻¹⁰ or less with a sulfur atom, to the polyarylene sulfide resin in the mixture (A), and washing with water in the range of 20 to 280°C. 【Chemistry 1】 (In the formula, Ar is an aryl group having a halogen atom, R １ R represents a hydrogen atom or an alkyl group or cyclohexyl group having 1 to 3 carbon atoms. ２ (where X represents an alkylene group with 3 to 5 carbon atoms, and X represents a hydrogen atom or an alkali metal atom.)

2. A method for producing a polyarylene sulfide resin according to claim 1, wherein the pH of the slurry before adding a salt containing a metal element to the mixture (A) in step (4) is 11 or less.

3. A method for producing a polyarylene sulfide resin according to claim 1 or 2, wherein the proportion of compound (1) represented by the following structural formula (1) is 2000 ppm or less. 【Chemistry 2】 (In the formula, Ar is an aryl group having a halogen atom, R １ R represents a hydrogen atom or an alkyl group or cyclohexyl group having 1 to 3 carbon atoms. ２ (where X represents an alkylene group with 3 to 5 carbon atoms, and X represents a hydrogen atom or an alkali metal atom.)

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