Polyarylene sulfide

Abstract

The purpose is to provide a polyarylene sulfide which is easy to mix uniformly with a conventionally known polyarylene sulfide, and which yields a composition that does not tend to decrease in melt viscosity even after passage of time after blending with polyarylene sulfide.　A polyarylene sulfide is used which has two integrated values related to two specific peaks that satisfy a specific inequality and two integrated values related to two other peaks that satisfy another inequality when a mixture of 4.0 mg of a sample obtained by a method that includes obtaining an extract from polyarylene sulfide by Soxhlet extraction using chloroform and washing, then drying the extract to obtain a sample for 1H-NMR measurement, 5.0 mg of 1,3,5-trimethoxybenzene, and 0.7 mL of deuterated chloroform is measured by 1H-NMR standardized so that a resonance peak based on chloroform in deuterated chloroform is 7.26 ppm.

Description

Polyarylene sulfide

[0001] This invention relates to polyarylene sulfide.

[0002] Polyarylene sulfides (hereinafter also referred to as "PAS"), typified by polyphenylene sulfide (hereinafter also referred to as "PPS"), are engineering plastics with excellent heat resistance, chemical resistance, flame retardancy, mechanical strength, electrical properties, and dimensional stability. PAS can be molded into various molded products, films, sheets, fibers, etc., by common melting processes such as extrusion molding, injection molding, and compression molding. For this reason, PAS is widely used in a wide range of technological fields, including electrical equipment, electronic equipment, automotive equipment, and packaging materials.

[0003] However, PAS has a problem in that it is prone to burr formation during molding due to its low melt viscosity. For this reason, it has been proposed to add various alkoxysilane compounds to prevent burr formation (see Patent Documents 1 and 2). Various alkoxysilane compounds have high reactivity with PAS resin and have been shown to improve mechanical properties and suppress burr formation. However, since alkoxysilane compounds are easily hydrolyzed, the desired burr suppression effect may not be obtained if hydrolysis occurs due to moisture in the PAS resin or in the air, for example.

[0004] Therefore, various proposals have been made to suppress burr formation without using alkoxysilane compounds. Patent document 3 describes a PAS resin composition containing a trifunctional epoxy resin.

[0005] Japanese Patent Publication No. 6-21169 Publication No. 1-146955 Publication No. 2023-91755

[0006] When extrusion molding is performed using a mixture containing PAS and an alkoxysilane compound, it is sometimes necessary to dry blend the PAS and the alkoxysilane compound and then immediately melt-mix them. Because alkoxysilane compounds are prone to deterioration due to moisture absorption, if the alkoxysilane compound in the mixture undergoes hydrolysis due to moisture absorption, it is often difficult to obtain the thickening effect in the molten state derived from the alkoxysilane compound. In addition, epoxy group-containing compounds with three or more functions may have high viscosity at room temperature, so dry-blending them with PAS may make uniform mixing difficult.

[0007] The present invention has been made in view of the above problems, and aims to provide a polyarylene sulfide that is easily mixed uniformly with conventionally known polyarylene sulfides and that provides a composition in which the melt viscosity does not decrease easily even after time has elapsed since being compounded with the polyarylene sulfide.

[0008] The inventors used a sample solution prepared under specific conditions to normalize the resonance peak based on chloroform in deuterated chloroform to 7.26 ppm. １ We have discovered that the above objective can be achieved by using a polyarylene sulfide, which satisfies a specific inequality when measured by H-NMR (proton nuclear magnetic resonance), with respect to a conventionally known PAS, such that two integral values ​​relating to two specific peaks satisfy a specific inequality, and two integral values ​​relating to two other peaks satisfy another inequality. This led to the completion of the present invention. Specifically, the present invention is configured as follows: [1] to [5].

[0009] [1] Soxhlet extraction of polyarylene sulfide using chloroform; recovery of the extract obtained by the Soxhlet extraction; washing the extract with acetone at 23°C ± 1°C, and then drying at 80°C or below. １To obtain a sample for 1H-NMR analysis, a mixture of 4.0 mg of the sample obtained by a method including , 5.0 mg of 1,3,5-trimethoxybenzene, and 0.7 mL of deuterated chloroform was normalized so that the resonance peak based on chloroform in the deuterated chloroform was 7.26 ppm. １ When measured by H-NMR, if the integral value of the peak observed in the range of 6.03 to 6.15 ppm is Hs, the integral value of the peak observed in the range of 4.58 to 4.89 ppm is Ha, and the integral value of the peak observed in the range of 4.00 to 4.25 ppm is Hb, then the following equation (I): 1000 × (Ha + Hb / 2) / (Hs / 3) ≥ 0.6 ... (I) is satisfied. If the integral value of the peak observed in the range of 3.00 to 3.20 ppm is Ha', and the integral value of the peak observed in 2.75 to 2.83 ppm is Hb', then the following equation (II): (Ha' / 2 + Hb') / (Ha + Hb / 2) > 1.5 ... (II) is satisfied.

[0010] [2] The polyarylene sulfide according to [1], wherein the Hb and Hs satisfy the following formula (III): 1000 × (Hb / 2) / (Hs / 3) < 0.2 ... (III).

[0011] [3] The specific surface area measured by the BET method (single-point method) using a mixed gas of nitrogen and helium (nitrogen:helium = 30:70 (volume ratio)) as the adsorbent gas is 5 m². ２ / g or more 120m ２ A polyarylene sulfide according to [1] or [2], wherein the amount is less than or equal to / g.

[0012] [4] The specific surface area measured by the BET method (single-point method) using a mixed gas of nitrogen and helium (nitrogen:helium = 30:70 (volume ratio)) as the adsorbent gas is 5 m². ２ The values ​​are greater than or equal to / g, at a temperature of 310°C and a shear rate of 1200 sec. －１A method for producing polyarylene sulfide, comprising: a mixing step of mixing untreated polyarylene sulfide having a melt viscosity of 1 Pa·s or more as measured under certain conditions, a nitrogen atomic weight of 200 ppm by mass or more, and a sodium content of 500 ppm by mass or less with a polyfunctional epoxy group-containing compound; and a reaction step of reacting the mixture obtained in the mixing step at 230°C or below under substantially solvent-free conditions.

[0013] [5] The method for producing polyarylene sulfide according to [4], further comprising the steps of washing and / or drying the untreated polyarylene sulfide at or below the glass transition temperature of the untreated polyarylene sulfide before the above step.

[0014] The present invention aims to provide a polyarylene sulfide that is readily mixed uniformly with conventionally known polyarylene sulfides and that provides a composition in which the melt viscosity does not decrease easily even after time has elapsed since being blended with the polyarylene sulfide.

[0015] The embodiments of the present invention will be described in detail below. The present invention is not limited to the embodiments described below, and can be modified as appropriate without altering the essence of the invention.

[0016] Furthermore, unless otherwise specified in this specification, numerical ranges expressed using "~" refer to a range that includes the numbers written before and after "~" as the lower and upper limits, and "A~B" refers to a range that is A or greater and B or less. Furthermore, unless otherwise specified in this specification, "room temperature" refers to a temperature of 20°C or greater and 25°C or less, and "melt viscosity" refers to a temperature of 310°C and a shear rate of 1200 sec. －１ This refers to the melt viscosity measured under these conditions, and "under reduced pressure conditions" means that the absolute pressure is 10 Torr or less.

[0017] The polyarylene sulfide according to the present invention will be described below.

[0018] The polyarylene sulfide according to the present invention is a polyarylene sulfide (hereinafter also referred to as "PAS1") that satisfies formulas (I) and (II) above.

[0019] PAS1 has, as a main constituent, a repeating unit of -(Ar-S)- which has a structure in which an arylene group (hereinafter also referred to as "Ar") is bonded to a sulfide. Examples of Ar include p-phenylene group, m-phenylene group, o-phenylene group, substituted phenylene group, p,p'-diphenylene sulfone group, p,p'-biphenylene group, p,p'-diphenylene ether group, and naphthalene group.

[0020] PAS1 can be a homopolymer containing any one of the above repeating units alone, or a copolymer containing two or more of the above repeating units. As the homopolymer, polyphenylene sulfide in which Ar has a p-phenylene group is preferable.

[0021] In Ar of PAS1, any group selected from the group consisting of p-phenylene group, m-phenylene group and o-phenylene group accounts for preferably 50% by weight or more, p-phenylene group accounts for more preferably 80% by weight or more, still more preferably 90% by weight or more, and particularly preferably 98% by weight or more. Having such a structure is preferable in terms of heat resistance and crystallinity.

[0022] Hereinafter, a method for producing PAS1 will be described.

[0023] <Method for Producing PAS1> The method for producing PAS1 is not particularly limited. As an example of a preferable method for producing PAS1, an untreated polyarylene sulfide (hereinafter also referred to as "untreated PAS") obtained by polymerizing a sulfur source and a dihaloaromatic compound in N-methyl-2-pyrrolidone (hereinafter also referred to as "NMP") according to a known method is reacted with a compound having three or more epoxy groups in one molecule (hereinafter also referred to as "polyfunctional epoxy group-containing compound").

[0024] PAS1 produced by the above method has a large number of epoxy groups derived from the polyfunctional epoxy group-containing compound at its terminals. As a result, when PAS1 is mixed with conventionally known PAS, the epoxy groups of PAS1 favorably react with the functional groups capable of reacting with epoxy groups present at the molecular chain terminals of conventionally known PAS, and the melt viscosity of the resulting mixture can be easily increased. Further, PAS1 is easily uniformly mixed with conventionally known PAS, and provides a composition whose melt viscosity is unlikely to decrease even when time elapses after mixing. This makes it possible to stably increase the melt viscosity of PAS and also suppress the generation of burrs. In the present specification, conventionally known PAS and untreated PAS are distinguished from each other. Conventionally known PAS refers to PAS produced by a conventional method, and untreated PAS refers to PAS that serves as a raw material for PAS1 among conventionally known PAS.

[0025] (Untreated PAS) Untreated PAS will be described. The specific surface area of untreated PAS measured by the BET method (single-point method) using a mixed gas consisting of nitrogen and helium (nitrogen:helium = 30:70 (volume ratio)) as the adsorption gas is 5 m ２ / g or more, the melt viscosity is 1 Pa·s or more, the amount of functional groups that react with epoxy groups is 14 µmol / g or more, and the sodium content is 1200 ppm by mass or less, the untreated PAS can be used without particular limitation.

[0026] The specific surface area of untreated PAS is 5 m ２ / g or more, 10 m ２ / g or more and 120 m ２ / g or less is preferable, 15 m ２ / g or more and 120 m ２ / g or less is more preferable, 20 m ２ / g or more and 100 m ２ / g or lower is more preferred. When the specific surface area falls within this range, the unmodified PAS can be caused to react satisfactorily with the polyfunctional epoxy group-containing compound. In order to obtain such a specific surface area, in the production of unmodified PAS, the method can be carried out by performing a method of recovering the mixture, in which PAS after the polymerization reaction is dissolved, by slow cooling and crystallization (quenching method), or a method of recovering the mixture by volatilizing the solvent from the post-reaction mixture at high temperature (flash method). In the present specification, the term "specific surface area" refers to a value measured by the BET method (single-point method) based on ISO 9277 using a mixed gas consisting of nitrogen and helium as an adsorption gas (nitrogen:helium = 30:70 (volume ratio)).

[0027] The melt viscosity of unmodified PAS is 1 Pa·s or higher, preferably 5 Pa·s or higher and 250 Pa·s or lower, more preferably 15 Pa·s or higher and 200 Pa·s or lower, and even more preferably 20 Pa·s or higher and 150 Pa·s or lower. PAS having such a melt viscosity can be obtained by adjusting the amount of the dihaloaromatic compound relative to the amount of the sulfur source. PAS having a melt viscosity of less than 1 Pa·s is PAS mainly containing low-molecular-weight components such as oligomers, so falling within the above range distinguishes the PAS from those mainly containing low-molecular-weight components.

[0028] Examples of functional groups that react with epoxy groups (hereinafter also referred to as "epoxy-reactive functional groups") include phenolic hydroxyl groups, mercapto groups, and MABA terminal groups. PAS1 can be obtained by reacting unmodified PAS having such an epoxy-reactive functional group with a polyfunctional epoxy group-containing compound. The epoxy-reactive functional group is preferably a MABA terminal group from the viewpoint that it can be easily introduced into unmodified PAS when NMP is used as a polymerization solvent.

[0029] The above-mentioned "MABA terminal group" refers to a terminal group derived from a by-product generated by ring-opening of NMP produced by a side reaction during polymerization, which is contained in unprocessed PAS produced using NMP as a solvent, represented by "-NCH ３ -CH ２ CH ２ CH ２ -COOH".

[0030] The amount of epoxy-reactive functional groups per gram of untreated PAS is 14 μmol / g or more, preferably 14 μmol / g to 93 μmol / g, more preferably 36 μmol / g to 93 μmol / g, and even more preferably 36 μmol / g to 71 μmol / g. Having the amount of epoxy-reactive functional groups within this range allows for good reaction between untreated PAS and polyfunctional epoxy group-containing compounds.

[0031] Furthermore, if the Ar group in polyarylene sulfide is a p-phenylene group, m-phenylene group, o-phenylene group, p,p'-diphenylene sulfone group, p,p'-biphenylene group, p,p'-diphenylene ether group, or naphthalene group, then the epoxy-reactive functional group can be said to be located at the end of the molecular chain.

[0032] Furthermore, the amounts of phenolic hydroxyl groups and mercapto groups can be measured, for example, by the purge-trap method, and since the amount of MABA terminal groups is the same as the nitrogen atom content of untreated PAS, the nitrogen atom content can be treated as the amount of MABA terminal groups. The nitrogen atom content is measured using the trace nitrogen analyzer described in the examples, and can be converted to the amount of substance per gram of PAS (μmol / g) by dividing by the atomic weight of nitrogen (14.00). Since the nitrogen atom content can be determined in units of mass ppm, the nitrogen atom content of untreated PAS should be 200 mass ppm or more, preferably 500 mass ppm to 1300 mass ppm, and more preferably 500 mass ppm to 1000 mass ppm.

[0033] Furthermore, in the method for producing untreated PAS, the amount of MABA terminal groups can be adjusted by performing polymerization under conditions where the sulfur source and dihalo-aromatic compounds are at high concentrations, or by adjusting the amount of alkali metal hydroxide added.

[0034] The sodium content of untreated PAS (hereinafter also referred to as "Na content") is 1200 ppm by mass or less, preferably greater than 0 ppm by mass and 1000 ppm by mass or less, more preferably greater than 0 ppm by mass and 800 ppm by mass or less, and even more preferably greater than 0 ppm by mass and 200 ppm by mass or less. The Na content is measured using inductively coupled plasma emission spectroscopy (ICP-AES) as described in the examples. The Na content can be adjusted by washing the untreated PAS, and within the above range, it can react well with alicyclic polyfunctional epoxy group-containing compounds.

[0035] (Method for producing untreated PAS) Untreated PAS as described above can be obtained by a general manufacturing method comprising a preparation step of preparing a preparation mixture containing NMP, a sulfur source, and a dihalo-aromatic compound, and a polymerization step of heating the mixture to carry out a polymerization reaction (see, for example, Japanese Patent Publication No. 61-7332, Japanese Patent Publication No. 2004-244619, Japanese Patent Publication No. 9-286861, etc.). In addition to the preparation step and the polymerization step, the method may also include a dehydration step to reduce the amount of water in the mixture, a post-treatment step, a prepolymerization step to generate a PAS prepolymer, a phase separation step to add a phase separation agent to the mixture to form a phase-separated state, and a post-polymerization step to carry out a further polymerization reaction after phase separation.

[0036] (Sulfur source and dihalo-aromatic compound) The sulfur source and dihalo-aromatic compound are not particularly limited, and those commonly used in the production of PAS can be used. Each of the sulfur source and the dihalo-aromatic compound may be used alone, or two or more may be used in combination, as long as it is possible to produce untreated PAS having the desired chemical structure. In the specification and claims of this application, "dihalo-aromatic compound" means an aromatic compound in which two hydrogen atoms directly attached to the aromatic ring are replaced by halogen atoms.

[0037] Examples of sulfur sources include alkali metal sulfides, alkali metal hydrosulfides, and hydrogen sulfide, with alkali metal sulfides and alkali metal hydrosulfides being preferred, and alkali metal hydrosulfides being more preferred. The sulfur source can be handled in either the form of an aqueous slurry or an aqueous solution, and from the viewpoint of handling, such as metering and transportability, it is preferable to be in the form of an aqueous solution. Examples of alkali metal sulfides include lithium sulfide, sodium sulfide, potassium sulfide, rubidium sulfide, and cesium sulfide. Examples of alkali metal hydrosulfides include lithium hydrosulfide, sodium hydrosulfide, potassium hydrosulfide, rubidium hydrosulfide, and cesium hydrosulfide.

[0038] Examples of dihaloaromatic compounds include o-dihalobenzene, m-dihalobenzene, p-dihalobenzene, dihalotoluene, dihalonaphthalene, methoxy-dihalobenzene, dihalobiphenyl, dihalobenzoic acid, dihalodiphenyl ether, dihalodiphenyl sulfone, dihalodiphenyl sulfoxide, and dihalodiphenyl ketone. The halogen atoms refer to fluorine, chlorine, bromine, and iodine atoms, and two or more halogen atoms in a dihaloaromatic compound may be the same or different. Among these, p-dihalobenzene, m-dihalobenzene, and mixtures thereof are preferred in terms of availability and reactivity, with p-dihalobenzene being more preferred, and p-dichlorobenzene (hereinafter also referred to as "pDCB") being particularly preferred.

[0039] The amount of dihalo-aromatic compound in the fermentation mixture (described later) is preferably 0.90 moles to 1.50 moles, and more preferably 0.92 moles to 1.10 moles, per mole of sulfur source in the fermentation mixture (hereinafter also referred to as "fermentation sulfur source"). When the amount of dihalo-aromatic compound used is within the above range, it is easy to generate high molecular weight polymers, and thus an untreated PAS with high melt viscosity can be obtained.

[0040] (NMP) From the viewpoint of the efficiency of the polymerization reaction, the amount of NMP used is preferably 1 mole to 30 moles, and more preferably 3 moles to 15 moles, per mole of sulfur source used.

[0041] The sulfur source described above may be mixed with NMP and subjected to the dehydration process.

[0042] (Dehydration Process) The dehydration process is a process performed before the charging process in which at least a portion of the water-containing distillate is discharged from the system containing a mixture of NMP and a sulfur source. The mixture subjected to the dehydration process may optionally contain alkali metal hydroxides. The water to be dehydrated in the dehydration process includes water contained in each raw material charged in the dehydration process, the aqueous medium of the aqueous mixture, and water produced as a by-product of the reaction between the raw materials.

[0043] The heating temperature in the dehydration step is not particularly limited, but is preferably 300°C or lower, and more preferably 100°C to 250°C. It is desirable to dehydrate the mixture until the water content in the mixture is 0.5 moles to 2.4 moles per 1.0 mole of sulfur source. If the water content becomes too low in the dehydration step, water can be added in the preparation step preceding the polymerization step to adjust it to the desired water content.

[0044] (Preparation Process) The preparation process is the process of preparing a mixture containing NMP, a sulfur source, and a dihalo-aromatic compound. The mixture prepared in the preparation process is also called the "preparation mixture."

[0045] When a dehydration process is performed, the sulfur source used in the brewing process can be calculated by subtracting the amount of hydrogen sulfide volatilized during the dehydration process from the amount of sulfur source added as a raw material.

[0046] When a dehydration process is performed, alkali metal hydroxides and water may be added to the mixture remaining in the system after the dehydration process during the preparation process, as needed. As alkali metal hydroxides, those commonly used in the production of PAS can be used, such as lithium hydroxide, sodium hydroxide, potassium hydroxide, rubidium hydroxide, and cesium hydroxide. Alkali metal hydroxides may be used individually or in mixtures of two or more types.

[0047] The number of moles of alkali metal hydroxide is calculated based on the number of moles of alkali metal hydroxide added as needed during the initial stage, the number of moles of alkali metal hydroxide added as needed during the dehydration stage (if applicable), and the number of moles of alkali metal hydroxide generated during the dehydration stage in conjunction with the generation of hydrogen sulfide. By adjusting the amount of alkali metal hydroxide in the initial mixture, the nitrogen atom content of the untreated PAS can be adjusted.

[0048] In the fermentation mixture, the amounts of NMP and dihalo-aromatic compounds used are set, for example, within the ranges indicated above for NMP and dihalo-aromatic compounds, per mole of sulfur source used.

[0049] (Polymerization Process) The polymerization process is a process in which the preparation mixture is heated to initiate the polymerization reaction and produce PAS. From the viewpoint of the efficiency of the polymerization reaction, the polymerization temperature is preferably 170°C to 300°C, and more preferably 180°C to 290°C. The temperature may be maintained at a constant level, or it may be raised or lowered in stages or continuously as needed. In order to obtain high molecular weight untreated PAS, the polymerization reaction may be carried out in two or more stages. For example, when the phase separation agent described later is added during polymerization, the process is carried out in two or more stages, and the process of producing a prepolymer before the addition of the phase separation agent is called the pre-polymerization process, and the process of continuing the polymerization reaction after the addition of the phase separation agent is called the post-polymerization process. The mixture heated in the polymerization process is called the "reaction mixture".

[0050] The conversion rate of the dihalo-aromatic compound at the end of the preceding polymerization step is preferably 60 mol% to 98 mol%, and more preferably 65 mol% to 98 mol%. The conversion rate of the dihalo-aromatic compound can be calculated by determining the amount of dihalo-aromatic compound remaining in the reaction mixture by gas chromatography, and then calculating the amount of dihalo-aromatic compound and sulfur source added.

[0051] The phase separation agent addition step is the step of adding a phase separation agent to the starting mixture and / or reaction mixture. The phase separation agent can be one that is commonly used in the production of PAS. Examples of phase separation agents include water, metal organic carboxylates, metal organic sulfonic acid salts, and alkali metal halides. Among these, water and / or metal organic carboxylates are preferred, and water is more preferred. The amount of phase separation agent used varies depending on the type of compound used, but is preferably in the range of 0.01 moles to 20 moles per 1 kg of NMP, and when water is used as the phase separation agent, it is preferably 2 moles to 7 moles.

[0052] There is no specific timing for adding the phase separation agent; it may be added during the preparation process, at the start of the polymerization process, or in the middle of the polymerization process, with adding it in the middle of the polymerization process being preferable. The presence of the phase separation agent allows the polymerization reaction to proceed in a phase-separated state. When the phase separation process is performed in the middle of the polymerization process, a state with a high concentration of prepolymer can be formed by liquid-liquid phase separation. As a result, the prepolymers bond together, the chains grow further, and a high molecular weight polymer is obtained. Also, when the phase separation agent is added in the middle of the polymerization process, the specific surface area of ​​the untreated PAS can be increased by reducing the amount of phase separation agent used within a range where phase separation is possible.

[0053] In the subsequent polymerization step, the amount of alkali metal hydroxide used is preferably 1.00 mole to 1.10 moles, more preferably 1.01 mole to 1.08 moles, and even more preferably 1.02 mole to 1.07 moles per mole of sulfur source. When the amount of alkali metal hydroxide is within the above range, the molecular weight of the resulting untreated PAS tends to increase more easily, and it is easier to obtain untreated PAS with a higher molecular weight. In the subsequent polymerization step, it is preferable to add alkali metal hydroxide to the reaction mixture so that the final amount of alkali metal hydroxide is within the above range, based on the amount of alkali metal hydroxide present in the reaction mixture after the preceding polymerization step.

[0054] (Post-treatment and recovery steps) The untreated PAS produced by the method described above may be recovered through a post-treatment and recovery step. The post-treatment and recovery steps can be carried out by conventional methods. For example, by cooling the reaction mixture, a slurry containing granular polymer products can be obtained. The cooled product slurry can be filtered, either as is or diluted with water, and then washed and filtered repeatedly to recover the untreated PAS. Drying is preferably carried out under reduced pressure.

[0055] By generating granular untreated PAS using the method described above, the granular untreated PAS can be separated from the reaction solution and recovered by, for example, sieving it using a 100-mesh screen (mesh opening diameter 150 μm). This allows for easy separation of the untreated PAS from by-products and oligomers.

[0056] Suitable washing solvents for untreated PAS include organic polar solvents such as NMP, ketones (e.g., acetone), alcohols (e.g., methanol), and water. Alternatively, granular untreated PAS may be treated with an aqueous solution containing an acid or a salt such as ammonium chloride, and multiple washing steps using these solvents may be combined. It is preferable to treat with at least one of hot water (e.g., 170°C or higher) and an acidic aqueous solution, with treatment with an acidic aqueous solution being preferable. During the polymerization of untreated PAS, sodium salts such as sodium chloride are produced as by-products, and may exist as "-COONa" where the hydrogen of the carboxyl group in the MABA terminal group is replaced by sodium. By treating untreated PAS with hot water and / or an acidic aqueous solution, the Na content is reduced, meaning the carboxyl group in the MABA terminal group can be acidified (-COOH), which facilitates the reaction with the alicyclic epoxy group-containing compound described later. Furthermore, reducing the Na content increases the crystallization rate, making it suitable for injection molding applications.

[0057] Here, when performing the washing and / or drying steps (hereinafter also referred to as "washing and / or drying") of the untreated PAS, it is preferable that the washing and / or drying temperature be below the glass transition temperature of the untreated PAS (for example, 93°C or below). By using such temperature conditions, the end groups of the untreated PAS remain on the outer surface of the PAS particles and become reactive end groups.

[0058] Although the detailed mechanism is not clear, it is thought to be as follows: In organic polar solvents, particularly NMP, the affinity between the organic polar solvent and the terminal functional groups in untreated PAS is high. Therefore, even if the untreated PAS is heated above the glass transition temperature where molecular motion is active, the terminal functional groups remain on the solvent side, i.e., on the outer surface of the PAS. On the other hand, if the process involves contact with water or air, which has a low affinity for the terminal functional groups, it is possible that the terminal functional groups will fold or burrow into the interior of the untreated PAS, which has a higher affinity than water or air. Therefore, it is desirable to process at a temperature where molecular motion is not active. In the case of PPS, a temperature of 93°C or lower, which is below the glass transition temperature, is preferred, and a temperature of 20°C to 93°C is more preferred.

[0059] Furthermore, even when washing and / or drying under conditions above the glass transition temperature, it is possible to obtain the reaction-active end groups described above by heating the untreated PAS in an organic polar solvent at a temperature that does not melt (for example, 95°C to 230°C) and drying it at a temperature below the glass transition temperature of the PAS. However, as described later, this may reduce the amount of PAS containing MABA end groups, so it is preferable to perform the washing and / or drying process of the untreated PAS at a temperature below the glass transition temperature.

[0060] The organic polar solvent is not particularly limited as long as it is a solvent commonly used in PAS production, but organic amide solvents having an amide bond in their molecular structure are preferred, and amide compounds having an aliphatic cyclic structure such as N-methyl-ε-caprolactam, NMP, and N-cyclohexyl-2-pyrrolidone are more preferred, with NMP being particularly preferred.

[0061] By using reactive terminal groups, untreated PAS and polyfunctional epoxy group-containing compounds can be reacted well even under temperature conditions where the untreated PAS does not melt or dissolve, and even under substantially solvent-free conditions. The glass transition temperature of untreated PAS can be measured by known methods, such as using a differential scanning calorimeter (DSC) in accordance with ISO 11357-2 (2020).

[0062] "Substantially solvent-free" means that the presence of inert gases or solids in the reaction system is not prevented, as long as they do not adversely affect the reaction and do not substantially reduce the substrate concentration. Specifically, this means that the total amount of untreated PAS and solvent substances other than the polyfunctional epoxy group-containing compound is 30% by weight or less and 10% by weight or less relative to the total amount of untreated PAS, polyfunctional epoxy group-containing compound, and solvent substances.

[0063] By the method described above, untreated PAS, which is the raw material for PAS1, can be obtained.

[0064] (Method for producing PAS1) A method for producing PAS1 includes a mixing step of mixing untreated PAS with a polyfunctional epoxy group-containing compound, and a reaction step of reacting the mixture obtained in the mixing step at a temperature of 230°C or lower and under substantially solvent-free conditions.

[0065] In addition to the above steps, the process may also include steps of washing and / or drying the untreated PAS as described above, and washing and / or drying PAS1.

[0066] The polyfunctional epoxy group-containing compound is not particularly limited and may be a glycidyl group-containing compound, or an alicyclic epoxy group-containing compound having an epoxy group composed of two adjacent carbon atoms and an oxygen atom constituting an alicyclic ring, such as an epoxycycloalkyl group. Among these, an alicyclic epoxy group-containing compound is preferred from the viewpoint of being able to react better with untreated PAS with reduced Na content. This makes it possible to increase the melt viscosity when PAS1 is blended with untreated PAS.

[0067] In this specification, a polyfunctional epoxy group-containing compound refers to an epoxy group-containing compound having three or more epoxy groups per molecule. From the viewpoint of suppressing burr formation, it is preferable that the epoxy group content be four or more. Epoxy group-containing compounds having four epoxy groups have very high viscosity, and therefore, when added during melt mixing, they do not exhibit the same uniformity as conventionally known PAS. However, the method of the present invention allows for uniform mixing with conventionally known PAS.

[0068] Suitable examples of glycidyl group-containing compounds include novolac epoxy resins such as phenol novolac type epoxy resins, brominated phenol novolac type epoxy resins, orthocresol novolac type epoxy resins, bisphenol A novolac type epoxy resins, and bisphenol AD ​​novolac type epoxy resins; cyclic aliphatic epoxy resins such as epoxy compounds of dicyclopentadiene type phenol resins; aromatic epoxy resins such as epoxy compounds of naphthalene type phenol resins; glycidylamine type epoxy resins such as tetraglycidylaminodiphenylmethane, triglycidyl-p-aminophenol, tetraglycidylmetaxylylenediamine, and 4,4'-methylenebis(N,N-diglycidylaniline); and heterocyclic epoxy resins such as triglycidyl isocyanurate.

[0069] Examples of compounds having alicyclic epoxy groups include, for example, compounds represented by formulas (i-1) to (i-3) that have three or more alicyclic epoxy groups in one molecule. In formula (ii-1) below, n1 to n6 represent integers from 1 to 30.

[0070]

[0071] The amount of the polyfunctional epoxy group-containing compound used is sufficiently excessive compared to the amount of epoxy-reactive functional groups in the untreated PAS. Preferably, the amount of the polyfunctional epoxy group-containing compound is 30 molar times or more relative to the amount of epoxy-reactive functional groups. There is no particular upper limit, but it is preferably 200 molar times or less.

[0072] The reaction between untreated PAS and polyfunctional epoxy group-containing compounds is typically carried out under substantially solvent-free conditions. PAS having MABA-terminated groups is less likely to be converted to high molecular weight compared to PAS having other functional groups such as mercapto groups. Therefore, when the reaction is carried out in a solvent and under the temperature conditions described later, PAS having MABA-terminated groups may leach into the solvent, making it difficult to recover the PAS that has reacted with the polyfunctional epoxy group-containing compound. As a result, the amount of PAS that has reacted with the polyfunctional epoxy group-containing compound in the solids recovered after the reaction may be small, potentially making it difficult to obtain the effects of the present invention. Under substantially solvent-free conditions, it is possible to prevent PAS having MABA-terminated groups from leaching into the solvent, and PAS1 can be easily recovered.

[0073] The reaction temperature is not particularly limited as long as it is a temperature at which the untreated PAS does not melt or dissolve, but for example, 30°C to 230°C is preferred, and 60°C to 150°C is more preferred. When reacting the polyfunctional epoxy group-containing compound with the untreated PAS under conditions where the PAS melts or dissolves, there is a risk that unreacted polyfunctional epoxy group-containing compounds will be incorporated into the PAS, which may cause plasticization, leading to a decrease in physical properties such as crystallinity and chemical resistance derived from the PAS, and a decrease in melt viscosity when added to conventionally known PAS. On the other hand, by reacting at a temperature at which the untreated PAS does not melt or dissolve, the unreacted polyfunctional epoxy group-containing compounds can be removed by the washing operation described later to the extent that the above-mentioned decrease in physical properties does not occur. The reaction time is typically preferably 30 minutes to 24 hours, and more preferably 1 hour to 12 hours.

[0074] As described above, the untreated PAS is reacted with a polyfunctional epoxy group-containing compound, the reaction mixture is cooled (for example, to 40°C or below), and the solids in the reaction mixture are recovered by filtration. The recovered solids are washed with an organic solvent, water, etc., and then dried as necessary to obtain polyarylene sulfide corresponding to PAS1.

[0075] Examples of organic solvents used for washing include organic polar solvents commonly used in the polymerization of untreated PAS, ketones (e.g., acetone), alcohols (e.g., methanol), ethers (e.g., diethyl ether), halogenated hydrocarbons (e.g., chloroform), etc. Ketones, alcohols, and ethers are preferred because they have a high affinity for the polyfunctional epoxy group-containing compound but not too high an affinity for PAS. Furthermore, when untreated PAS and the polyfunctional epoxy group-containing compound are reacted under substantially solvent-free conditions, the polyfunctional epoxy group-containing compound may not be recoverable by filtration due to its high viscosity. In such cases, the reaction mixture may be cooled (e.g., to 40°C or below) before adding the solvent. Unreacted polyfunctional epoxy compounds removed by washing can be recovered from the solution after washing and reused. To efficiently remove unreacted polyfunctional epoxy group-containing compounds while increasing the recovery efficiency of PAS1, the washing step of PAS1 is preferably carried out at 80°C or below, and more preferably between 10°C and 40°C. The drying step can be carried out in the same manner as in conventional methods for producing PAS, and is preferably carried out under reduced pressure.

[0076] <PAS1> PAS1 is subjected to Soxhlet extraction using chloroform, the extract obtained by Soxhlet extraction is recovered, the recovered extract is washed with acetone under conditions of 23°C ± 1°C, and then dried at 80°C or below. １ A mixture of 4.0 mg of a sample obtained by a method including obtaining a sample for H-NMR analysis, 5.0 mg of 1,3,5-trimethoxybenzene, and 0.7 mL of deuterated chloroform was normalized so that the resonance peak based on chloroform in the deuterated chloroform was 7.26 ppm. １When measured by 1H-NMR, if the integral value of the peak observed in the range of 6.03 to 6.15 ppm is Hs, the integral value of the peak observed in the range of 4.58 to 4.89 ppm is Ha, and the integral value of the peak observed in the range of 4.00 to 4.25 ppm is Hb, then the following equation (I): 1000 × (Ha + Hb / 2) / (Hs / 3) ≥ 0.6 ... (I) is satisfied. If the integral value of the peak observed in the range of 3.00 to 3.20 ppm is Ha', and the integral value of the peak observed in 2.75 to 2.83 ppm is Hb', then the following equation (II): (Ha' / 2 + Hb') / (Ha + Hb / 2) > 1.5 ... (II) is satisfied. This is a polyarylene sulfide.

[0077] １ The extract used for preparing samples for H-NMR measurement is extracted by Soxhlet extraction using chloroform as the solvent. The Soxhlet extraction method involves obtaining an extract from polyarylene sulfide (PAS1), washing the extract by the method described below, and drying it at 80°C or below. １ A method comprising obtaining a sample for H-NMR measurement, １ The method is not particularly limited as long as it yields a sample volume of 4.0 mg for use in 1H-NMR measurement. Soxhlet extraction can be performed, for example, using a fully automated Soxhlet extractor (Soxtherm 414, manufactured by Gerhard Japan Co., Ltd.) in the manner described in the examples.

[0078] "Extract" refers to the solid obtained after removing chloroform from a chloroform solution obtained by Soxhlet extraction of PAS1 by heating it at a temperature of 80°C or lower. Drying at room temperature and pressure or heated and reduced-pressure drying at a temperature of 80°C or lower (for example, solvent removal using an evaporator) may be combined. Chloroform removal is continued until the sum of the weight of the container and the weight of the extract inside the container no longer decreases.

[0079] ​The above extract is washed by the following method. First, ultrasonic washing is performed for 10 minutes with acetone at a weight of 500 times or more relative to the weight of the extract. Next, the washed extract is recovered by filtration using a membrane filter. Then, the recovered material is washed on the membrane filter with acetone at a weight of 600 times or more relative to the weight of the recovered extract, and this operation is repeated five times. If the series of operations using ultrasonic washing and acetone at a weight of 600 times the weight of the extract is considered as one cycle, the above series of washing operations is repeated three times. The extract washed in this way should be dried at a temperature of 80°C or lower, preferably between 10°C and 80°C. For example, drying may be performed under reduced pressure, and drying is continued until the weight of the extract no longer decreases.

[0080] H Ｓ This is the integral value of the peak originating from the hydrogen atoms bonded to the benzene ring in the reference substance, 1,3,5-trimethoxybenzene. The value obtained by integrating with a starting point of 6.03 ppm and an ending point of 6.15 ppm is defined as Hs, and this value is set to 3000. In this case, if the starting point and / or ending point are located above the baseline, the integral value obtained by aligning it with the baseline near the peak is calculated.

[0081] Ha is the integral value of the peak originating from the hydrogen atom bonded to the carbon atom bonded to the non-carbonyl oxygen atom in the ester bond (-O-CO-) at the group formed by the reaction of an alicyclic epoxy group and an MABA-terminated group. When an alicyclic epoxy group and an MABA-terminated group react, isomers may be produced. As a result, multiple peaks may be observed. Therefore, when multiple peaks are observed between 4.58 and 4.89 ppm, the sum of the integral values ​​of each peak is calculated, and the relative value of this sum is calculated with Hs set to 3000, and this is defined as Ha.

[0082] Hb is the integral value of the peak originating from the hydrogen atom bonded to the carbon atom bonded to the non-carbonyl oxygen atom in the ester bond (-O-CO-) at the group formed by the reaction of the glycidyl group and the MABA terminal group. Even when the sample is prepared by the method described above, impurities may be present in the sample. If impurities are present in the sample, multiple peaks may be observed between 4.00 and 4.25 ppm. When multiple peaks are observed in this range, the sum of the integral values ​​of each peak is calculated. The relative value of this sum, with Hs set to 3000, is calculated and this is defined as Hb.

[0083] Since the integral values ​​of the peaks corresponding to Ha and Hb are small relative to Hs, the peaks corresponding to Ha or Hb can be identified by zooming in on the vertical axis by approximately 100 to 1000 times and adjusting the display range. Furthermore, for Ha and Hb, if the integral value of one peak is less than 0.1 when Hs is set to 3000, it is determined that there is no structure affecting that peak, and the integral value is treated as 0. If the start and end points of a peak are not on the baseline, the integral value of Ha or Hb is calculated by aligning it with the baseline near the peak.

[0084] When Ha, Hb, and Hs satisfy 1000 × (Ha + Hb / 2) / (Hs / 3) ≥ 0.6, it indicates that the ratio of the integral value of the peak derived from a specific hydrogen atom contained in the functional group produced by the reaction between the alicyclic epoxy group or glycidyl group and the MABA terminal group is high to the integral value of the peak derived from the hydrogen atom present in the reference substance. In this case, PAS1 can be said to be rich in alicyclic epoxy groups or glycidyl groups derived from polyfunctional epoxy group-containing compounds.

[0085] The upper limit of 1000 × (Ha + Hb / 2) / (Hs / 3) is not particularly limited, but may be less than 4.3. Preferably, the value of 1000 × (Ha + Hb / 2) / (Hs / 3) is 0.6 or more and less than 4.3, more preferably 2.0 or more and less than 4.3, and more preferably 3.0 or more and 4.0 or less. Methods for increasing 1000 × (Ha + Hb / 2) / (Hs / 3) include increasing the amount of MABA terminal groups in the untreated PAS, increasing the amount of the bifunctional epoxy group-containing compound reacted with the untreated PAS, and performing the washing and / or drying steps of the untreated PAS at or below the glass transition temperature of the untreated PAS.

[0086] In formula (II), Ha' is the integral value of the peak derived from the alicyclic epoxy group. Hb' is the integral value of the peak derived from the glycidyl group. Since the integral values ​​of the peaks corresponding to Ha' and Hb' are small compared to Hs, the peaks corresponding to Ha' or Hb' can be identified by adjusting the display range by magnifying the vertical axis by 100 to 1000 times.

[0087] Furthermore, isomers may exist depending on the structure of the molecular chain ends of PAS1. If isomers exist, multiple peaks may appear corresponding to Ha' or Hb'. In that case, the sum of the integral values ​​of each peak is taken as Ha' and Hb'. If the start and end points of a peak are not on the baseline, the integral value when aligned with the baseline near the peak is taken as Ha' or Hb'. Note that if the integral value of one peak is less than 0.1 when Hs is 3000, it is determined that there is no structure related to that peak, and the integral value is treated as 0. In equation (II), the numerator (Ha' / 2 + Hb') represents the integral value of the peak derived from the proton of the unreacted epoxy group. In equation (II), the denominator (Ha + Hb / 2) represents the integral value of the peak derived from the proton produced by the reaction between the polyfunctional epoxy compound and the MABA terminal group. Therefore, equation (II) means that the integral value of the peak derived from the proton of the unreacted epoxy group is more than 1.5 times greater than the integral value of the peak derived from the proton produced by the reaction between the polyfunctional epoxy group-containing compound and the MABA terminal group, which means that this is PAS obtained by reacting untreated PAS with a polyfunctional epoxy group-containing compound.

[0088] The upper limit of (Ha' / 2 + Hb') / (Ha + Hb / 2) is not particularly limited, but may be less than 10.0. The value of (Ha' / 2 + Hb') / (Ha + Hb / 2) is preferably greater than 1.5 and less than 10.0, more preferably greater than 1.5 and 3.0 or less, and even more preferably 2.0 or greater and 3.0 or less.

[0089] By incorporating the above-mentioned PAS1 into a conventionally known PAS, PAS1 reacts well with the epoxy-reactive functional groups contained in the conventionally known PAS, and as a result, the melt viscosity of both the conventionally known PAS and the composition containing PAS1 can be increased. Furthermore, when increasing the melt viscosity of a conventionally known PAS by incorporating a silane coupling agent or the like, if the resulting composition is exposed to high humidity conditions, the melt viscosity of the composition may decrease due to hydrolysis of the silane coupling agent. In contrast, PAS1 is less susceptible to hydrolysis even under high humidity conditions, so the melt viscosity of the composition does not decrease easily. The conventionally known PAS is not particularly limited, but in order to increase the reactivity of PAS1 with the epoxy groups, it is preferable that the Na content of the conventionally known PAS is low, for example, 1200 ppm by mass or less is preferred.

[0090] Furthermore, it is preferable that Hb and Hs in PAS1 satisfy the following formula (III): 1000 × (Hb / 2) / (Hs / 3) < 0.2 ... (III)

[0091] The fact that Hb and Hs in PAS1 satisfy formula (III) indicates that the amount of functional group formed by the reaction of the glycidyl group and the MABA terminal group is small. In other words, it means that PAS1 has no glycidyl group or very little of it. Note that 1000 × (Hb / 2) / (Hs / 3) may be 0.

[0092] Furthermore, the specific surface area of ​​PAS1 is 5 m². ２ / g or more 100m ２ Preferably less than / g, and 10m ２ / g or more 80m ２ More preferably less than / g, and 30m ２ / g or more 60m ２A value of less than or equal to / g is even more preferable. The fact that the specific surface area of ​​PAS1 is within the above range indicates that PAS1 is a microporous granular resin, and is a distinguishing feature from conventional resin compositions obtained by kneading a mixture containing PAS and a polyfunctional epoxy group-containing compound at a temperature condition in which PAS melts. Furthermore, being within the above range results in excellent washability. Therefore, it is easy to remove unreacted polyfunctional epoxy group-containing compounds, and it is possible to prevent a decrease in physical properties due to the plasticizing effect derived from these compounds. The specific surface area of ​​PAS1 is usually adjusted by adjusting the specific surface area of ​​untreated PAS.

[0093] Polyfunctional epoxy group-containing compounds are often liquid at room temperature. Therefore, when thickening PAS by melt-mixing conventionally known PAS with a polyfunctional epoxy group-containing compound, the polyfunctional epoxy group-containing compound may adhere to the inside of mixing equipment such as a Henschel mixer when blending the conventionally known PAS and the polyfunctional epoxy group-containing compound before melt-mixing. However, as described above, when blending PAS1 obtained by reacting untreated PAS with a polyfunctional epoxy group-containing compound with conventionally known PAS, PAS1 is in a solid state, so PAS1 is less likely to adhere to the inside of the mixing equipment. Therefore, when thickening PAS by blending PAS1 with conventionally known PAS, there is no loss of the polyfunctional epoxy group-containing compound due to adhesion to the inside of the mixing equipment.

[0094] Furthermore, polyfunctional epoxy group-containing compounds tend to have high viscosity at room temperature (e.g., 200 mPa·s or higher). When conventionally known PAS and polyfunctional epoxy group-containing compounds are mixed at room temperature, it is difficult to mix them uniformly. This may result in inconsistent quality of the resulting resin composition. Also, if a large amount of polyfunctional epoxy group-containing compound is added to obtain a uniform resin composition, it may act as a plasticizer, potentially reducing the melt viscosity. In contrast, since PAS1 does not exhibit viscosity at room temperature, it can be uniformly mixed with conventionally known PAS, thus ensuring consistent quality of the resulting resin composition. In addition, unreacted polyfunctional epoxy group-containing compounds can be removed by washing, which can suppress the reduction in melt viscosity and the amount of gas generated during melting.

[0095] PAS1 was subjected to a temperature of 310°C and a shear rate of 1200 sec. －１ The melt viscosity measured under these conditions is preferably 1 Pa·s to 250 Pa·s, more preferably 15 Pa·s to 200 Pa·s, and even more preferably 20 Pa·s to 150 Pa·s.

[0096] The present invention is not limited to the embodiments described above, and various modifications are possible. Embodiments obtained by appropriately combining the technical means disclosed in this specification are also included within the technical scope of the present invention. Furthermore, all documents cited in this specification are incorporated herein by reference.

[0097] The present invention will be described in more detail below with reference to examples and comparative examples. The methods for measuring various characteristics and physical properties are as follows.

[0098] (Method for measuring melt viscosity) The melt viscosity was measured using a Capillograph F-1 manufactured by Toyo Seiki. A 1 mmφ × 10 mm angled inlet die was used as the capillary. 20.0 g of PPS was introduced into a device heated to 310°C, held at 310°C for 5 minutes, and then subjected to a shear rate of 1200 sec. －１ The melt viscosity was measured using the following method. The sample quantity used for measuring the melt viscosity of mixture A, described later, was 19.9 g.

[0099] (Method for measuring extract volume) The amount of extract obtained from 3.0 g of PPS using chloroform was measured using a fully automatic Soxhlet extractor (Soxtherm 414) manufactured by Gerhardt Japan. The extraction conditions were a heating temperature of 170°C, a boiling extraction time of 60 minutes, and a washing extraction time of 90 minutes, with 150 mL of chloroform used as the solvent. In this case, the total extraction time was 2.5 hours, which is the sum of the boiling extraction time and the washing extraction time. After the extraction operation was completed, the glass container of the Soxhlet extractor containing the extract was left in a fume hood at room temperature (23°C) for 15 hours to allow some of the chloroform to evaporate. Then, it was placed in a vacuum dryer and dried under reduced pressure at 80°C for 4 hours to dry the extract in the glass container. After removing the glass container from the vacuum dryer, the temperature of the glass container was returned to room temperature in a desiccator. Subsequently, the total weight of the obtained dry extract and the glass container was measured. The mass of the dried extract obtained by the extraction procedure was calculated by subtracting the weight of the dry glass container stored in the desiccator, which was measured before the extraction procedure, from the total weight measured. The extract amount (weight %), which is the ratio of the mass of the dried extract to the weight of PPS, was calculated using the following formula (1): Extract amount (weight %) = Weight of dried extract obtained by the extraction procedure (g) / Weight of sample used in the extraction procedure (g) × 100 ... (1)

[0100] (Method for measuring nitrogen atom content (Method for measuring MABA terminal group content)) 10 mg of PPS was accurately weighed, and the nitrogen atom content (mass ppm) was determined by elemental analysis using a trace nitrogen analyzer (TN-2100H, manufactured by Nitto Seiko Analytech Co., Ltd.). The nitrogen atom content (μmol / g) was calculated by dividing the result by the atomic weight of nitrogen (14.00). The temperature of the sample injection section was set to 800°C, the temperature of the reaction section to 900°C, and the gas flow rate to 300 mL / min. A calibration curve was prepared using a toluene solution of pyridine with a known concentration, and the nitrogen atom content was determined by interpolation.

[0101] (Method for measuring Na content) 0.5 g of PPS, 5 mL of 96% by mass sulfuric acid, and 2 mL of 33±3% by mass hydrogen peroxide solution were added to a 30 mL Kelder flask and heated for 40 minutes. After heating, the entire volume was transferred to a 50 mL volumetric flask and diluted with pure water. The Na content of the obtained solution was determined using ICP-AES (Hitachi High-Tech Corporation, ICP emission spectrometer "SPS3500DD"). The Na content was determined by interpolation using a calibration curve prepared with commercially available standard solutions.

[0102] (Method for Measuring Specific Surface Area using the BET Method) The specific surface area was measured using the BET method (single-point method) in accordance with ISO 9277, using a specific surface area measuring device (manufactured by Anton Paar, Monosorb®). 0.1 g of PPS was placed in a sample cell, and the sample was heated at 105°C for 3 hours while flowing a mixed gas of nitrogen and helium (nitrogen:helium = 30:70 (volume ratio)). After the heated sample cooled to room temperature (23°C), the sample cell was cooled with liquid nitrogen to adsorb nitrogen gas onto the sample. Adsorption was considered complete when the fluctuation of the nitrogen flow rate stopped. After adsorption was complete, cooling was stopped and nitrogen was desorbed. Desorption was considered complete when the fluctuation of the nitrogen flow rate stopped. The specific surface area of ​​PPS was calculated using the following formula (2). Specific surface area (m²) ２ / g) = Surface area of ​​the sample (m²) calculated from the nitrogen adsorption amount based on ISO 9277 ２ ) / Sample weight (weight after attachment / detachment - container weight) (g) ... (2)

[0103] ( １ (H-NMR Measurement Method) Soxhlet extraction with chloroform was performed under the same conditions as the extraction amount measurement method described above. After the extraction operation was completed, the glass container of the Soxhlet extractor containing the extract was left in a fume hood at room temperature (23°C) for 15 hours to allow some of the chloroform to evaporate. Then, it was placed in a vacuum dryer and dried under reduced pressure at 80°C to dry the extract in the glass container. After removing the glass container from the vacuum dryer, the temperature of the glass container was returned to room temperature in a desiccator to obtain the dried extract.

[0104] 10 mg of the obtained dried extract and 5 g of acetone were added to a 30 mL vial, and ultrasonic washing was performed for 10 minutes. The washed extract was recovered by filtration using a membrane filter. On the recovered solids, 60 g of acetone was added to the suction filter bottle under atmospheric pressure, stirred with a spatula for 30 seconds, and then filtered under reduced pressure using an aspirator. This process was repeated a total of five times. Furthermore, the ultrasonic washing, filtration, and washing on the membrane filter were repeated two more times to obtain a washed extract. Washing on the membrane filter was performed so that the entire extract was covered with acetone. The thus washed extract was dried under reduced pressure at 80°C for 4 hours. １ A sample for H-NMR measurement was obtained.

[0105] １ A mixture of 4.0 mg of sample for H-NMR measurement, 7.0 mL of deuterated chloroform, and 5.0 mg of 1,3,5-trimethoxybenzene is prepared. １ The sample was prepared for 1H-NMR measurement. The measurement conditions were as follows. The results were analyzed using Delta for Windows v6.3.0 manufactured by JEOL Ltd. １ Based on the 1H-NMR measurement results, the integral values ​​of the following equations (I), (II), (III), and (IV) were calculated, with Hs being the integral value of the peak observed in the range of 6.03 to 6.15 ppm, Ha being the integral value of the peak observed in the range of 4.58 to 4.89 ppm, Hb being the integral value of the peak observed in the range of 4.00 to 4.25 ppm, Ha' being the integral value of the peak observed in the range of 3.00 to 3.20 ppm, and Hb' being the integral value of the peak observed in 2.75 to 2.83 ppm. These values ​​are shown in Table 2.

[0106] ​Note that when Hs is set to 3000, if the integral value of one peak is less than 0.1, the integral value is treated as 0. When both Ha and Hb are 0, (Ha + Hb / 2) is 0. In this case, the value of the left side of equation (II) cannot be calculated. For this reason, when both Ha and Hb are 0, it is written as "-" in Table 2. (Measurement conditions) Equipment: JNM-ECZ600R / S1 (manufactured by JEOL Ltd.) Resonance frequency: 600 MHz Measurement temperature: Room temperature (23°C; no temperature adjustment) Number of cumulative measurements: 8192 (Formula used for calculation) 1000 × (Ha + Hb / 2) / (Hs / 3) ... (I) (Ha' / 2 + Hb') / (Ha + Hb / 2) ... (II) 1000 × (Hb / 2) / (Hs / 3) ... (III) 1000 × Ha / (Hs / 3) ... (IV)

[0107] [Manufacturing Example 1 (Untreated PPS-1)] 5000g of NMP was placed in a 20L autoclave. After creating a nitrogen gas atmosphere inside the autoclave, the NMP inside the autoclave was heated to 100°C over 1 hour while stirring at a stirrer speed of 250 rpm. After reaching 100°C, 1200g of a 74.0% by mass NaOH aqueous solution, 21.4 moles of NaSH, and Na ２ 2000 g of an aqueous sulfur source solution containing 0.36 moles of sulfur, along with 1000 g of NMP, were added to an autoclave. The mixture in the autoclave was then gradually heated to 200°C over 2 hours. During the heating process to 200°C, 1028 g of water, 760 g of NMP, and 0.36 moles of hydrogen sulfide were discharged from the autoclave.

[0108] Next, the mixture in the autoclave was cooled to 170°C, and at the same temperature, 3359 g of p-DCB (p-dichlorobenzene), 2920 g of NMP, 173 g of water, and 5.9 g of NaOH at a concentration of 97% by mass were added to the autoclave. At the end of the addition, the temperature of the mixture in the autoclave was 130°C. Next, while stirring at a stirrer speed of 250 rpm, the mixture in the autoclave was heated to 180°C over 30 minutes, and then heated from 180°C to 220°C over 60 minutes. After that, the mixture in the autoclave was heated to 260°C over 90 minutes to carry out the preliminary polymerization.

[0109] After the initial polymerization stage was completed, the stirrer speed was increased to 400 rpm, and 443 g of water was injected into the autoclave as a phase-separating agent. After the water was injected, the temperature of the reaction solution was raised to 260°C, and the reaction was continued at this temperature for 3 hours to carry out the subsequent polymerization stage.

[0110] After the subsequent polymerization was completed, the reaction mixture was cooled to near room temperature, and then the reaction mixture was passed through a 100-mesh screen to recover the granular polymer. The recovered granular polymer was then washed three times with acetone, three times with water, once with a 0.3% by mass aqueous acetic acid solution, and four times with water, in that order under room temperature conditions. All washing operations were carried out using a washing solvent in a weight ratio of at least five times the weight of the PPS recovered by sieving through the screen, under conditions that allowed the PPS to be fully immersed. The washed granular polymer was dried at 80°C (below the glass transition temperature of PPS) for 4 hours under reduced pressure to obtain untreated PPS-1.

[0111] [Manufacturing Example 2 (Untreated PPS-2)] 5000g of NMP was placed in a 20L autoclave. After creating a nitrogen gas atmosphere inside the autoclave, the NMP in the autoclave was heated to 100°C over 1 hour while stirring at 250 rpm. After reaching 100°C, 1470g of a 74.0% by mass NaOH aqueous solution, 2340g of a 62.4% by mass NaSH aqueous solution, and 1000g of NMP were added to the autoclave. The mixture in the autoclave was then gradually heated to 200°C over 2 hours. During the heating to 200°C, 1200g of water, 800g of NMP, and 0.36 moles of hydrogen sulfide were discharged from the autoclave.

[0112] Next, the mixture in the autoclave was cooled to 170°C, and at the same temperature, 3973 g of p-DCB (p-dichlorobenzene), 2466 g of NMP, 26 g of water, and 2 g of NaOH at a concentration of 97% by mass were added to the autoclave. At the end of the addition, the temperature of the mixture in the autoclave was 130°C. Next, while stirring at a stirrer speed of 250 rpm, the mixture in the autoclave was heated to 180°C over 30 minutes, and then heated from 180°C to 220°C over 60 minutes. After that, the mixture in the autoclave was heated to 260°C over 90 minutes to carry out the preliminary polymerization.

[0113] After the initial polymerization stage was completed, the stirrer speed was increased to 400 rpm, and 443 g of water was injected into the autoclave as a phase-separating agent. After the injection of water, the temperature of the reaction solution was raised to 260°C in 0.5 hours, and the reaction was continued at the same temperature for 3 hours to carry out the subsequent polymerization stage.

[0114] The recovery and post-treatment steps following the subsequent polymerization were carried out in the same manner as in Production Example 1 to obtain untreated PPS-2.

[0115] [Production Example 3 (Untreated PPS-3)] Pre-polymerization and post-polymerization were carried out with a starting amount of 3379g of p-DCB. The subsequent recovery and post-treatment processes were carried out in the same manner as in Production Example 1, except that acetone washing was performed three times followed by water washing three times. Untreated PPS-3 was obtained.

[0116] For the untreated PPS-1, untreated PPS-2, and untreated PPS-3 obtained in Production Examples 1 to 3, the melt viscosity, specific surface area, Soxhlet extract amount, nitrogen atom content, and Na content were measured using the method described above. The results are shown in Table 1.

[0117]

[0118] [Example 1] 16 g of untreated PPS-1 obtained in Production Example 1, 40 g of alicyclic tetrafunctional epoxy group-containing compound-1 represented by the above formula (i-3) (KR-470, manufactured by Shin-Etsu Chemical Co., Ltd.), and a stirring bar were placed in a 100 mL round-bottom flask. The contents of the round-bottom flask were stirred at 120°C for 8 hours to react the untreated PPS-1 with epoxy compound-1. After the reaction, the mixture was allowed to cool to room temperature, and the solids were collected from the reaction solution in the round-bottom flask onto filter paper (No. 5A) using a spatula. Since a small amount of solids remained in the round-bottom flask, the entire amount was collected using 10 g of acetone. The collected solids were transferred to the filter paper, 50 g of acetone was added to the suction filtration bottle under atmospheric pressure, and the mixture was stirred with a spatula for 30 seconds. Then, the suction filtration bottle was reduced in pressure using an aspirator and filtered a total of three times (i.e., 150 g of acetone was used for washing). Next, the washed solids, 100 g of acetone, and a stirring bar were placed in a 200 mL round-bottom flask, and the contents of the flask were stirred for 30 minutes. After stirring, the solids were collected from the reaction solution in the round-bottom flask using filter paper, and washed again with 150 mL of acetone and by stirring. After washing, the solids were collected from the reaction solution in the round-bottom flask using filter paper, and dried under reduced pressure at 80°C for 4 hours to obtain PPS (modified PPS-1) with its ends modified by epoxy compound-1.

[0119] [Example 2] Modified PPS-2 was obtained by the same method as in Example 1, except that untreated PPS-1 was replaced with untreated PPS-2 obtained in Production Example 2.

[0120] [Example 3] Modified PPS-3 was obtained by the same method as in Example 1, except that untreated PPS-1 was changed to untreated PPS-2 and the epoxy group-containing compound was changed to a glycidylamine-type tetrafunctional epoxy compound-2 (jER-604, manufactured by Mitsubishi Chemical Corporation).

[0121] [Comparative Example 1] Modified PPS-4 was obtained by the same method as in Example 1, except that untreated PPS-1 was replaced with untreated PPS-3.

[0122] [Comparative Example 2] 16 g of untreated PPS-1, 40 g of epoxy group-containing compound-1, 40 g of NMP, and a stirring bar were placed in a 200 mL round-bottom flask. The contents of the round-bottom flask were stirred at 120°C for 8 hours to react the untreated PPS-1 with the epoxy group-containing compound-1. The procedure was the same as in Example 1, except that the contents were stirred to obtain modified PPS-5.

[0123] [Comparative Examples 3 and 4] Untreated PPS-1 was used.

[0124] [Preparation of Mixture A] Mixture A was prepared using the PPS from Examples 1 to 3 and Comparative Examples 1 to 4 by the following method. For all mixtures, the polyethylene bag was shaken at a rate of at least 60 times per minute, with one shake counted as one shake in one direction.

[0125] [Examples 1-3, Comparative Examples 1-2] Modified PPS-1-5 obtained in Examples 1-3 and Comparative Examples 1-2, along with untreated PPS-1, were added to an antistatic polyethylene bag in the quantities shown in Table 2. The bag was shaken by hand for 1 minute at room temperature (23°C) to mix the modified PPS and untreated PPS-1 in the bag, obtaining mixture A of Examples 1-3 and Comparative Examples 1-2. [Comparative Examples 3-4] Untreated PPS-1 and 3-aminopropyltriethoxysilane, and untreated PPS-1 and epoxy group-containing compound-1 were added to an antistatic polyethylene bag in the quantities shown in Table 2. The bag was shaken by hand for 1 minute at room temperature (23°C) to mix the untreated PPS-1 and 3-aminopropyltriethoxysilane, and untreated PPS-1 and epoxy group-containing compound-1 in the bag, obtaining mixture A of Comparative Examples 3-4.

[0126] Using mixture A from Examples 1-3 and Comparative Examples 1-4, moisture resistance tests, viscosity evaluations, and mixability evaluations were performed using the methods described below.

[0127] (Humidity Resistance Test) Using 19.9 g of mixture A obtained in Examples 1-3 and Comparative Examples 1-4 as a sample, the melt viscosity (η1) before the humidity resistance test was measured using the melt viscosity measurement method described above. Using 19.5 g of mixture A that had been left to stand for 24 hours in an environment of 23°C and 63 RH% relative humidity as a sample, the melt viscosity (η2) after the humidity resistance test was measured using the same method. The rate of decrease in melt viscosity was calculated using the following formula (3). Rate of decrease in melt viscosity (%) = ((η1 - η2) / η1) × 100 ... (3)

[0128] If the melt viscosity reduction rate obtained from the above formula (3) is 2.5% or less, it can be said that the material has excellent moisture resistance.

[0129] (Thickening property evaluation) The thickening property of mixture A was evaluated using the following formula (4). In formula (4), M1 is the melt viscosity of the modified PPS mentioned above, and η1 is the melt viscosity of mixture A before the humidity resistance test. Also, Ln represents the natural logarithm. Ln(η1) / (0.357 × Ln(M1) + 2.14) ... (4)

[0130] Equation (4) is a modified form of the logarithmic mixing rule, which is known as a method for determining the average properties of a mixture when different resins are uniformly mixed, based on the physical properties of the different resins. If the value of equation (4) is 1.09 or higher, it can be said that the measured melt viscosity of mixture A is significantly higher than the predicted melt viscosity.

[0131] (Evaluation of Mixability) The mixing state of mixture A was evaluated visually. (Evaluation Criteria) 3 (Good): No uneven distribution of the sample was observed, and uniformity was sufficiently ensured. 2 (Acceptable): Some uneven distribution of the sample was observed, and the uniformity was moderate. 1 (Unacceptable): The uneven distribution of the sample was significant, and the uniformity was greatly impaired.

[0132] The specific surface area, Na content, and other parameters of the modified PPS-1 to modified PPS-5 obtained in Examples 1 to 3 and Comparative Examples 1 to 2, and the untreated PPS-1 from Comparative Examples 3 and 4, measured by the method described above, are as follows: １Table 2 shows the results of the 1H-NMR measurement, as well as the results of the humidity resistance test, viscosity evaluation, and mixability evaluation conducted using mixture A prepared as described above.

[0133]

[0134] Table 2 shows that PPS satisfying formulas (I) and (II) are readily mixed uniformly with conventionally known PAS, and that their melt viscosity does not decrease significantly even after time has passed since being compounded with conventionally known PAS. Furthermore, it can be seen that many epoxy groups can be easily introduced into PAS by reacting untreated PAS with a polyfunctional epoxy group-containing compound at a temperature of 230°C or below and under substantially solvent-free conditions.

[0135] [Discussion] Comparative Examples 1 and 2 do not satisfy formula (I), indicating that the tetrafunctional epoxy group-containing compound did not react sufficiently with the MABA terminal group of PPS. In Comparative Example 1, it is thought that the reaction with epoxy compound-1 did not proceed well because untreated PPS-3 with a high Na content was used. In Comparative Example 2, it is thought that the reaction was carried out in a solvent. Since PPS with MABA terminal groups often has a relatively low molecular weight, it is presumed that it eluted into the solvent and became difficult to recover during filtration and washing operations.

[0136] Comparative Example 3 showed a melt viscosity reduction rate of 7.0%. It is thought that the reaction with the reactive end groups of PPS (e.g., MABA end groups) did not proceed well because 3-aminopropyltriethoxysilane was hydrolyzed by moisture in the air when mixture A was allowed to stand after preparation. Comparative Example 4 showed a melt viscosity reduction rate of approximately 2.0%, but the evaluation of mixability using mixture A showed significant uneven distribution of the epoxy compound sample, resulting in a great loss of uniformity. In the humidity resistance test, the total amount of mixture A was set to be close to the amount required for measurement so that the melt viscosity measurement before and after the humidity resistance test would be under the same conditions as much as possible, and care was taken with the sampling, resulting in a relatively high viscosity increase. However, since much of the epoxy compound adhered to the polyethylene bag used when preparing mixture A, it is presumed that it is difficult to obtain a uniform pelletized composition or molded product.

Claims

1. Perform Soxhlet extraction of polyarylene sulfide using chloroform; collect the extract obtained by the Soxhlet extraction; wash the extract with acetone at 23°C ± 1°C, and then dry it at 80°C or below. １ To obtain a sample for 1H-NMR analysis, a mixture of 4.0 mg of the sample obtained by a method including , 5.0 mg of 1,3,5-trimethoxybenzene, and 0.7 mL of deuterated chloroform was normalized so that the resonance peak based on chloroform in the deuterated chloroform was 7.26 ppm. １ When measured by H-NMR, if the integral value of the peak observed in the range of 6.03 to 6.15 ppm is Hs, the integral value of the peak observed in the range of 4.58 to 4.89 ppm is Ha, and the integral value of the peak observed in the range of 4.00 to 4.25 ppm is Hb, then the following equation (I): 1000 × (Ha + Hb / 2) / (Hs / 3) ≥ 0.6 ... (I) is satisfied. If the integral value of the peak observed in the range of 3.00 to 3.20 ppm is Ha', and the integral value of the peak observed in 2.75 to 2.83 ppm is Hb', then the following equation (II): (Ha' / 2 + Hb') / (Ha + Hb / 2) > 1.5 ... (II) is satisfied.

2. The polyarylene sulfide according to claim 1, wherein the Hb and Hs satisfy the following formula (III): 1000 × (Hb / 2) / (Hs / 3) < 0.2 ... (III).

3. The specific surface area measured by the BET method (single-point method) using a mixed gas of nitrogen and helium (nitrogen:helium = 30:70 (volume ratio)) as the adsorption gas is 5 m². ２ / g or more 120m ２ The polyarylene sulfide according to claim 1 or 2, wherein the amount is less than or equal to / g.

4. The specific surface area measured by the BET method (single-point method) using a mixed gas of nitrogen and helium (nitrogen:helium = 30:70 (volume ratio)) as the adsorption gas is 5 m². ２ The values ​​are greater than or equal to / g, at a temperature of 310°C and a shear rate of 1200 sec. －１ A method for producing polyarylene sulfide, comprising: a mixing step of mixing untreated polyarylene sulfide having a melt viscosity of 1 Pa·s or more as measured under certain conditions, a nitrogen atomic weight of 200 ppm by mass or more, and a sodium content of 500 ppm by mass or less with a polyfunctional epoxy group-containing compound; and a reaction step of reacting the mixture obtained in the mixing step at 230°C or below under substantially solvent-free conditions.

5. The method for producing polyarylene sulfide according to claim 4, further comprising, before the mixing step, a step of washing and / or drying the untreated polyarylene sulfide at a temperature below the glass transition temperature of the untreated polyarylene sulfide.

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