Polyarylene sulfide copolymer particles and method for producing same

Abstract

Polyarylene sulfide copolymer particles each have a median diameter D50 of 1-1,000 μm inclusive, a glass transition point by differential scanning calorimetry of 95-190°C inclusive and a sphericity of 80-100 inclusive. The present invention addresses the problem of obtaining polyarylene sulfide copolymer particles having a high glass transition point and a high sphericity, and provides a simple and safe method for producing the same.

Description

Polyarylene sulfide copolymer particles and method for producing the same

[0001] The present invention relates to polyarylene sulfide copolymer particles and a method for producing the same.

[0002] Polyarylene sulfides, typified by polyphenylene sulfide (hereinafter sometimes abbreviated as PPS), have properties suitable for use as engineering plastics, such as excellent heat resistance, barrier properties, moldability, chemical resistance, electrical insulation, and moist heat resistance, and are used primarily in injection molding and extrusion molding applications, as well as in various electric and electronic parts, machine parts, automobile parts, films, fibers, etc. Due to their excellent properties, the range of applications in which polyarylene sulfides are used has expanded in recent years.

[0003] PPS, a typical polyarylene sulfide, is a crystalline polymer that generally has a glass transition point of 80 to 90°C and a melting point of 275 to 285°C, and is often used under high-temperature conditions due to its excellent heat resistance. It is also widely used in applications that take advantage of its excellent chemical resistance.

[0004] However, while the above-mentioned PPS, which is a typical example of polyarylene sulfide, has a high melting point and can withstand use at high temperatures, it has a problem in that its rigidity drops sharply at temperatures above the glass transition point, 80 to 90° C., compared to temperatures below that point. Various studies have been conducted to improve the glass transition point of polyarylene sulfide, and for example, Patent Documents 1 to 3 disclose polyarylene sulfide copolymers obtained by reacting polyarylene sulfide having a reactive functional group with rigid molecules.

[0005] Polyarylene sulfide copolymers, which have excellent chemical resistance and higher heat resistance, are generally used in injection molding, injection compression molding, blow molding, extrusion molding, etc., but by granulating the polyarylene sulfide copolymer, it becomes possible to use it as a heat-resistant additive in the fields of adhesive materials, paints, and polymer compounds, or as a raw material for three-dimensional modeling in powder bed fusion bonding, and it is expected that it will be useful in a wider range of applications. Furthermore, when a resin composition is produced by blending the polyarylene sulfide copolymer with components selected from fillers and other additives, it is expected that a more uniform resin composition can be obtained efficiently by using a particulate polyarylene sulfide copolymer.

[0006] Various methods for producing thermoplastic resin particles have been investigated. For example, Patent Documents 4 and 5 disclose PPS or polyarylene sulfide particles obtained by dissolving PPS or polyarylene sulfide in a solvent and precipitating the resulting solution. Patent Document 6 discloses a polyarylene sulfide resin powder obtained by subjecting polyarylene sulfide to a dry grinding treatment. Patent Documents 7 and 8 disclose PPS particles obtained by adding another thermoplastic polymer to PPS, melt-kneading the mixture, and then removing the other thermoplastic polymer.

[0007] International Publication No. 2019 / 151288 International Publication No. 2022 / 045105 International Publication No. 2021 / 020334 Japanese Patent Application Laid-Open No. 2008-231250 International Publication No. 2009 / 119466 International Publication No. 2019 / 203256 Japanese Patent Application Laid-Open No. 2014-43522 Japanese Patent Application Laid-Open No. 10-273594

[0008] Although the polyarylene sulfide copolymers disclosed in Patent Documents 1 to 3 have high glass transition points, the polyarylene sulfide copolymers are only produced by heating in a molten state in the absence of a solvent, and polyarylene sulfide copolymer particles have not been obtained. Furthermore, although there is a description of producing a polyarylene sulfide copolymer in the presence of a solvent, there is no description of particles or a specific production method. Patent Document 3 describes a method of using a powdered polyarylene sulfide copolymer as a method for producing a fiber-reinforced polyarylene sulfide copolymer composite substrate, but there is no description of a specific method for obtaining a powdered polyarylene sulfide copolymer or a method for producing a composite substrate using a powdered polyarylene sulfide copolymer.

[0009] The PPS or polyarylene sulfide particles disclosed in Patent Documents 4 and 5 are produced by dissolving PPS or polyarylene sulfide in a solvent and precipitating it. When this production method is applied to a polyarylene sulfide copolymer having a high glass transition point, the difference in solubility has led to problems of a decrease in particle yield and a decrease in the molecular weight of the polyarylene sulfide copolymer.

[0010] Patent Document 6 discloses a polyarylene sulfide resin powder for thermoplastic prepregs, but only describes a specific method for producing the powder, which involves dry pulverization. Generally, resin powders obtained by dry pulverization have irregular shapes, low sphericity, and poor fluidity and dispersibility. Furthermore, as with the inventions described in Patent Documents 1 to 3, the resin is in the form of pellets or chunks produced by heating in a molten state, which makes it difficult to granulate the resin by dry pulverization.

[0011] In Patent Documents 7 and 8, PPS particles are obtained, but a thermoplastic polymer other than PPS is added, and a long reaction time is required for decomposition to remove the thermoplastic polymer, and further there is a problem that workers are exposed to the solvent.

[0012] An object of the present invention is to provide polyarylene sulfide copolymer particles from which three-dimensional objects having high shaped object density and excellent surface quality, reinforced fiber composite substrates having excellent mechanical properties, and molded articles made therefrom can be obtained.

[0013] Another object of the present invention is to provide a simple and safe production method for obtaining polyarylene sulfide copolymer particles having a high glass transition point and high sphericity.

[0014] The present invention has been made to solve at least part of the above-mentioned problems, and can be realized by providing the following: 1. Polyarylene sulfide copolymer particles having a median diameter D50 of 1 μm or more and 1,000 μm or less, a glass transition point of 95° C. or more and 190° C. or less when measured using a differential scanning calorimeter, and a sphericity of 80 or more and 100 or less. 2. Polyarylene sulfide copolymer particles according to the above 1, having a median diameter D50 of 1 μm or more and 150 μm or less. 3. Polyarylene sulfide copolymer particles according to the above 1 or 2, having a weight-average molecular weight Mw of 30,000 or more. 4. Polyarylene sulfide copolymer particles according to any one of the above 1 to 3, wherein the polyarylene sulfide copolymer constituting the polyarylene sulfide copolymer particles contains at least one bonding group selected from a sulfonyl group, a sulfinyl group, an ester group, an amide group, an imide group, an ether group, a urea group, a urethane group, and a siloxane group. 5. 5. A method for producing polyarylene sulfide copolymer particles, comprising: step 1 of melt-kneading a polyarylene sulfide copolymer having a glass transition temperature of 95°C or higher and 190°C or lower as measured using a differential scanning calorimeter with a water-soluble thermoplastic resin; and step 2 of removing the water-soluble thermoplastic resin by washing with water or an alcohol. 6. A method for producing polyarylene sulfide copolymer particles as described above in 5, wherein the viscosity ratio ηa / ηb of the melt viscosity (ηa) of the polyarylene sulfide copolymer to the melt viscosity (ηb) of the water-soluble thermoplastic resin is 0.1 or higher and 1,000 or lower. 7. A dispersion in which the polyarylene sulfide copolymer particles of any of 1 to 4 above are dispersed in a liquid. 8. A three-dimensionally shaped product molded from the polyarylene sulfide copolymer particles of any of 1 to 4 above. 9. A method for producing a reinforced fiber composite substrate, comprising the steps of dispersing the polyarylene sulfide copolymer particles of any of 1 to 4 above in reinforcing fibers, and melting the polyarylene sulfide copolymer particles to impregnate the reinforcing fibers. 10. A reinforced fiber composite substrate produced by the method for producing a reinforced fiber composite substrate according to the above item 9. 11. A molded article obtained by molding the reinforced fiber composite substrate according to the above item 10. 12. The molded article according to the above item 11, which is an aircraft structural member.

[0015] According to the present invention, it is possible to provide polyarylene sulfide copolymer particles having a high glass transition point and high sphericity, and a simple and safe method for producing the same.

[0016] Furthermore, the polyarylene sulfide copolymer particles of the present invention can be used to obtain three-dimensional shaped articles having high shaped article density and excellent surface quality. Furthermore, the polyarylene sulfide copolymer particles of the present invention have excellent dispersibility when dispersed in reinforcing fibers, and can provide reinforcing fiber composite substrates having excellent mechanical properties, and molded articles made thereof.

[0017] Hereinafter, embodiments of the present invention will be described in detail.

[0018] [Polyarylene sulfide copolymer particles] The lower limit of the glass transition point of the polyarylene sulfide copolymer particles is 95°C or higher, preferably 100°C or higher, and more preferably 110°C or higher. If the glass transition point is below 95°C, high rigidity cannot be obtained under high temperature conditions. The upper limit of the glass transition point is 190°C or lower, preferably 180°C or lower, and more preferably 160°C or lower. If the glass transition point exceeds 190°C, the chemical resistance of the molded article will be insufficient. The glass transition point is defined as the inflection point of the baseline shift detected when the polyarylene sulfide copolymer particles are heated from 0°C to 340°C at a rate of 20°C / min using a differential scanning calorimeter.

[0019] In order to obtain polyarylene sulfide copolymer particles having a glass transition point within the above range, for example, the molecular structure of the polyarylene sulfide copolymer constituting the polyarylene sulfide copolymer particles may contain rigid bonding groups such as sulfonyl groups, sulfinyl groups, ester groups, amide groups, imide groups, ether groups, urea groups, urethane groups, and siloxane groups.

[0020] The crystallization temperature of the polyarylene sulfide copolymer particles is preferably 150°C or higher, more preferably 160°C or higher, and even more preferably 170°C or higher. When the lower limit of the crystallization temperature is within the above range, crystallization is facilitated during molding or when a resin composition is produced by blending components selected from fillers and other additives, resulting in excellent mechanical properties and chemical resistance, and improved productivity. There is no particular upper limit to the crystallization temperature, but a range of 235°C or lower can generally be exemplified. The crystallization temperature is the crystallization peak temperature detected when the polyarylene sulfide copolymer particles are heated from 0°C to 340°C at a rate of 20°C / min using a differential scanning calorimeter, then held at 340°C for 1 minute, and then cooled to 100°C at a rate of 20°C / min.

[0021] The polyarylene sulfide copolymer particles preferably have a melting point of 300°C or less, more preferably 270°C or less, and even more preferably 260°C or less. Having an upper limit of the melting point within the above range facilitates melt molding. Furthermore, a melting point of 200°C or more is preferable, and a melting point of 220°C or more is even more preferable. Having a lower limit of the melting point within the above range is preferable because sufficient heat resistance can be obtained when three-dimensionally shaped objects, reinforced fiber composite substrates, and molded articles made thereof are obtained. The melting point is the melting peak temperature detected when the polyarylene sulfide copolymer particles are heated from 0°C to 340°C at a rate of 20°C / min using a differential scanning calorimeter, then held at 340°C for 1 minute, cooled to 100°C at a rate of 20°C / min, held at 100°C for 1 minute, and then heated again to 340°C at a rate of 20°C / min.

[0022] The polyarylene sulfide copolymer forming the polyarylene sulfide copolymer particles is a copolymer containing 70 mol % or more, preferably 80 mol % or more, of arylene sulfide units. Here, the arylene sulfide unit is a repeating unit represented by the formula -(Ar-S)-. Ar may be a unit selected from the units represented by the following formulas (I) to (XI). Of these, the unit represented by formula (I) is particularly preferred.

[0023]

[0024] R １ , R ２ is a substituent selected from hydrogen, an alkyl group having 1 to 12 carbon atoms, an alkoxy group having 1 to 12 carbon atoms, an aryl group having 6 to 24 carbon atoms, a halogen group, and a reactive functional group; R １ and R ２ may be the same or different.

[0025] As long as the above repeating units are contained within the above ranges, a small amount of branching units or crosslinking units represented by the following formulas (XII) to (XIV) may further be contained. The copolymerization amount of these branching units or crosslinking units is preferably in the range of 0 to 1 mol % per 1 mol of -(Ar-S)- units.

[0026]

[0027] Here, Ar is a unit selected from the units represented by the above formulas (I) to (XI).

[0028] The arylene sulfide unit may be any of a random copolymer, a block copolymer, and a mixture thereof containing the above repeating unit.

[0029] Representative examples of these include polyphenylene sulfide, polyphenylene sulfide sulfone, polyphenylene sulfide ketone, their random copolymers, block copolymers, and mixtures thereof. Particularly preferred polyarylene sulfides include those having a p-phenylene sulfide unit represented by the following formula (XV) as the main structural unit of the polymer:

[0030]

[0031] and polyphenylene sulfide containing 80 mol % or more, particularly 90 mol % or more of the above.

[0032] The lower limit of the number average molecular weight Mn of the arylene sulfide unit in the polyarylene sulfide copolymer forming the polyarylene sulfide copolymer particles is preferably 1,000 or more, more preferably 1,500 or more, and even more preferably 2,000 or more. When the number average molecular weight of the arylene sulfide unit is in the above range, high chemical resistance tends to be obtained. The upper limit of the number average molecular weight of the arylene sulfide unit is preferably 10,000 or less, more preferably 6,000 or less, and even more preferably 4,000 or less. When the number average molecular weight of the arylene sulfide unit is in the above range, high heat resistance tends to be obtained.

[0033] Here, the number average molecular weight of the arylene sulfide units in the polyarylene sulfide copolymer refers to the number average molecular weight of the portion of the polyarylene sulfide copolymer derived from the polyarylene sulfide (A) described below. The number average molecular weight of the arylene sulfide units in the polyarylene sulfide copolymer can be determined by measuring the molecular weight of the residue (corresponding to the arylene sulfide units) obtained by decomposing the linking groups of the polyarylene sulfide copolymer using the method described below. As a method for decomposing the linking groups, known methods depending on the type of linking group can be used. For example, when the linking group is an imide group, a method of decomposing polyimide can be used. The linking groups can be decomposed by treating the polyarylene sulfide copolymer in an aqueous sodium hydroxide solution using the method described in JP 2006-124530 A, or by the method described in JP 2001-163973 A, in which the polyarylene sulfide copolymer is reacted in the presence of water or alcohol at a high temperature and pressure of 110°C or higher and 1 MPa or higher.

[0034] In order to set the number average molecular weight of the arylene sulfide units in the polyarylene sulfide copolymer within the above range, it is preferable to use, in the production of the polyarylene sulfide copolymer, a polyarylene sulfide (A) having a number average molecular weight Mn of 1,000 or more and 10,000 or less, as described below. The weight average molecular weight and number average molecular weight can be determined, for example, using SEC (size exclusion chromatography) equipped with a differential refractive index detector.

[0035] The polyarylene sulfide copolymer forming the polyarylene sulfide copolymer particles contains a structure derived from the copolymerization component in addition to the arylene sulfide units. Examples of structures derived from the copolymerization component contained in the polyarylene sulfide copolymer include structures containing aromatic rings. Structures selected from the structures represented by the formulas (a) to (s) are preferred, and structures selected from the structures represented by the formulas (a) to (e), (i), and (j) are more preferred, with the structure represented by the formula (i) being particularly preferred. By including these structures, the polymer tends to exhibit sufficient mechanical properties, chemical resistance, and rigidity at high temperatures.

[0036]

[0037] Here, R ３ , R ４ , and R ５ is a substituent selected from hydrogen, an alkyl group having 1 to 12 carbon atoms, an arylene group having 6 to 24 carbon atoms, and a halogen group; R ３ , R ４ , and R ５ may be the same or different.

[0038] In the polyarylene sulfide copolymer forming the polyarylene sulfide copolymer particles, the arylene sulfide units and copolymerization components may be linked via a structure other than each repeating unit, or the terminal groups derived from the repeating units may be directly linked to each other. The arylene sulfide units and copolymerization components are preferably linked via at least one bonding group selected from a sulfonyl group, a sulfinyl group, an ester group, an amide group, an imide group, an ether group, a urea group, a urethane group, and a siloxane group. Among these, linking via an imide group is more preferred. Linking via an imide group tends to exhibit higher rigidity at high temperatures.

[0039] The lower limit of the amount of linking groups linking the arylene sulfide units and copolymerization components is preferably 1 mol% or more, more preferably 2 mol% or more, and even more preferably 4 mol% or more, relative to the sulfur atoms contained in the polyarylene sulfide copolymer. By setting the amount of linking groups within the above range, it tends to be possible to sufficiently suppress a decrease in rigidity under high-temperature conditions. The upper limit of the amount of linking groups is preferably 60 mol% or less, more preferably 40 mol% or less, even more preferably 30 mol% or less, and even more preferably 20 mol% or less. While an increase in the amount of linking groups tends to decrease chemical resistance, setting it within the above range tends to exhibit sufficient mechanical properties and chemical resistance. The amount of linking groups can be calculated using the amount of functional groups contained in the polyarylene sulfide (A) and the amount of functional groups contained in the compound (B), which will be described later and are used in the production of the polyarylene sulfide copolymer, or it can be determined by measuring the FT-IR spectrum or NMR spectrum of the polyarylene sulfide copolymer particles.

[0040] The lower limit of the weight-average molecular weight of the polyarylene sulfide copolymer contained in the polyarylene sulfide copolymer particles is preferably 30,000 or more, more preferably 40,000 or more, and even more preferably 50,000 or more. If the weight-average molecular weight is less than 30,000, the mechanical properties of the polyarylene sulfide copolymer particles tend to be poor. There is no particular limit to the upper limit of the weight-average molecular weight, but a preferred example is 200,000 or less, more preferably 150,000 or less, and even more preferably 100,000 or less. When the upper limit of the weight-average molecular weight is within the above range, the moldability of the polyarylene sulfide copolymer particles tends to be excellent. The weight-average molecular weight can be determined, for example, using SEC (size exclusion chromatography) using a differential refractive index detector.

[0041] The lower limit of the median diameter D50 of the polyarylene sulfide copolymer particles is 1 μm or more. If D50 is less than 1 μm, the bulk density will be small, resulting in poor handleability, and the particles will be so fine that they tend to adhere to a recoater, for example, during three-dimensional modeling, resulting in poor handleability. The upper limit of D50 is 1000 μm. D50 is preferably 150 μm or less, more preferably 100 μm or less, even more preferably 70 μm or less, and most preferably 50 μm or less. If D50 exceeds 1000 μm, the particle size during three-dimensional modeling will exceed the stacking height, resulting in a rough surface, and when a resin composition is produced by blending fillers and / or other additives, a homogeneous resin composition cannot be obtained. From the viewpoint of obtaining molded products with smooth surfaces during three-dimensional modeling and obtaining homogeneous resin compositions during resin composition production, D50 is preferably 150 μm or less. The median diameter D50 is the particle size at which the cumulative frequency from the small particle size side of the particle size distribution measured with a laser diffraction particle size distribution analyzer is 50%. Polyarylene sulfide copolymer particles having a median diameter D50 of 1000 μm or less can be produced by the production method described below. In addition, the median diameter D50 can be adjusted, for example, by the type of solvent used to dissolve the polyarylene sulfide copolymer, the ratio of the polyarylene sulfide copolymer to the solvent, the cooling rate during precipitation of the polyarylene sulfide copolymer, stirring, etc.

[0042] The particle size distribution of the polyarylene sulfide copolymer particles is preferably 10 or less, more preferably 7 or less, even more preferably 5 or less, even more preferably 4 or less, and even more preferably 3 or less. The particle size distribution is expressed as D90 / D10, which is the ratio of D90 to D10, measured using a laser diffraction particle size distribution analyzer. The lower limit of D90 / D10 is theoretically 1.0. When the upper limit of D90 / D10 is within the above range, differences in melting properties due to differences in particle size tend to be reduced in three-dimensional modeling and resin composition production, resulting in the production of homogeneous molded objects and resin compositions. D90 / D10 is the value obtained by dividing the particle size (D90) at which the cumulative frequency from the small particle size side of the particle size distribution measured using the laser diffraction particle size distribution analyzer is 90% by the particle size (D10) at which the cumulative frequency from the small particle size side is 10%. Polyarylene sulfide copolymer particles having a D90 / D10 ratio within the above range can be produced by the production method described below. The D90 / D10 ratio can be adjusted, for example, by the cooling rate and stirring when precipitating the polyarylene sulfide copolymer particles.

[0043] The sphericity, which indicates the sphericity of the polyarylene sulfide copolymer particles, is 80 or more, and more preferably 90 or more. If the sphericity is less than 80, sufficient fluidity cannot be obtained during three-dimensional modeling, and the surface tends to become rough. Furthermore, when a resin composition is produced by blending a filler and / or other additives, it tends to be difficult to obtain a homogeneous resin composition. Furthermore, when the polyarylene sulfide copolymer particles are used as a dispersion, the viscosity of the dispersion tends to increase, making it difficult to handle. Theoretically, the upper limit of sphericity is 100, and a range of 100 or less is acceptable. The upper limit of sphericity is preferably 99 or less. The sphericity is calculated by observing the minor axis and major axis of 30 particles randomly selected from an optical microscope photograph of the polyarylene sulfide copolymer particles and calculating it according to the following formula.

[0044]

[0045] In the formula, S is the sphericity, n is the number of measurements, and a ｉ is the major axis of the i-th particle, b ｉis the minor axis of the i-th particle. The number of measurements, n, is 30. Polyarylene sulfide copolymer particles having a sphericity within the above range can be produced by the production method described below.

[0046] The smoothness of the surface of polyarylene sulfide copolymer particles and the solidity of the interior can be expressed by the BET specific surface area determined by gas adsorption. If the surface of the resin particles is smooth and the interior of the particles is solid, the surface area of ​​the particles is reduced, the fluidity is improved, and the surface of the resulting shaped object is smooth, which is preferable. Here, the smaller the BET specific surface area, the smoother the surface. Specifically, when the BET specific surface area is 10 m ２ / g or less, and more preferably 5m ２ / g or less, and more preferably 3m ２ / g or less, and particularly preferably 1m ２ / g or less, and most preferably 0.5m ２ The lower limit is theoretically 0.05 m / g when the particle diameter is 100 μm. ２ / g.

[0047] The BET specific surface area can be measured in accordance with Japanese Industrial Standards (JIS) JIS R 1626 (1996) "Method for measuring specific surface area by gas adsorption BET method."

[0048] The solidity of polyarylene sulfide copolymer particles can be evaluated by the ratio of the BET specific surface area to the theoretical specific surface area. The closer the ratio of the BET specific surface area to the theoretical specific surface area is to 1, the smoother the surface and the more solid the particles. The ratio is preferably 5 or less, more preferably 4 or less, even more preferably 3 or less, and most preferably 2 or less. Theoretically, the lower limit is 1. When the ratio of the BET specific surface area to the theoretical specific surface area is within the above range, the generation of voids can be suppressed when the polyarylene sulfide copolymer particles are used to mold a composite material, and excellent mechanical properties are exhibited, which is preferable. Furthermore, when used as a raw material for three-dimensional molding using a powder bed fusion method, the generation of voids inside and outside the three-dimensional molded product is suppressed, and excellent appearance and mechanical properties are exhibited, which is preferable. The theoretical specific surface area can be expressed as the ratio of the surface area to the weight of a single sphere calculated from the D50 particle size and density of the polyarylene sulfide copolymer particle, assuming that the polyarylene sulfide copolymer particle is a perfect sphere.

[0049] The polyarylene sulfide copolymer particles of the present invention preferably generate a small amount of organic gas when heated or melted. The polyarylene sulfide copolymer particles of the present invention can be used to obtain three-dimensional objects by lamination or melting, or to obtain reinforced fiber composite substrates with excellent mechanical properties and molded articles made thereof by dispersing or melt-impregnating them into reinforcing fibers. Both processes include a step of heating and melting the polyarylene sulfide copolymer particles, and the amount of organic gas is preferably small from the viewpoint of preventing voids from being mixed into the three-dimensional object, reinforcing fiber composite substrate, and molded article made thereof, and from the viewpoint of ensuring worker safety. From the above viewpoints, the polyarylene sulfide copolymer particles of the present invention are preferably finally washed with water and then dried.

[0050] [Method for Producing Polyarylene Sulfide Copolymer] The polyarylene sulfide copolymer used in the present invention is preferably produced by a method of heating polyarylene sulfide (A) having a number average molecular weight Mn of 1,000 or more and 10,000 or less, and at least one compound (B) selected from the formulae (a') to (u') (hereinafter, may be abbreviated as compound (B)).

[0051]

[0052] Here, X is at least one group selected from two carboxyl groups bonded to two adjacent carbon atoms, or an acid anhydride group derived from the two carboxyl groups, an amino group, a hydroxyl group, a carboxyl group, a silanol group, a sulfonic acid group, an acetamide group, a sulfonamide group, a cyano group, an isocyanate group, an aldehyde group, an acetyl group, an epoxy group, and an alkoxysilyl group. ３ , R ４ , and R ５ are each a substituent selected from hydrogen, an alkyl group having 1 to 12 carbon atoms, an arylene group having 6 to 24 carbon atoms, and a halogen group; R ３ , R ４ , and R ５ may be the same or different.

[0053] [Polyarylene sulfide (A)] Polyarylene sulfide (A) is a homopolymer or copolymer having a repeating unit represented by the formula -(Ar-S)- as a main structural unit. Here, "main structural unit" means that the repeating unit accounts for 70 mol% or more. Ar includes units represented by the above formulas (I) to (XI), among which the unit represented by formula (I) is particularly preferred.

[0054] As long as the above repeating units are contained within the above ranges, a small amount of branching units or crosslinking units represented by the following formulas (XII) to (XIV) may further be contained. The copolymerization amount of these branching units or crosslinking units is preferably in the range of 0 to 1 mol % per 1 mol of -(Ar-S)- units.

[0055] The polyarylene sulfide (A) may be any of a random copolymer, a block copolymer, and a mixture thereof containing the above repeating unit.

[0056] Representative examples of these include polyphenylene sulfide, polyphenylene sulfide sulfone, polyphenylene sulfide ketone, their random copolymers, block copolymers, and mixtures thereof. Particularly preferred polyarylene sulfides include polyphenylene sulfides containing p-phenylene sulfide units represented by the formula (XV) as the main structural unit of the polymer in an amount of preferably 80 mol % or more, particularly preferably 90 mol % or more.

[0057] The polyarylene sulfide (A) contains, as a functional group, at least one functional group selected from two carboxyl groups bonded to two adjacent carbon atoms, or an acid anhydride group derived from the two carboxyl groups, an amino group, a hydroxyl group, a carboxyl group, a silanol group, a sulfonic acid group, an acetamide group, a sulfonamide group, a cyano group, an isocyanate group, an aldehyde group, an acetyl group, an epoxy group, and an alkoxysilyl group. From the viewpoint of reactivity when the polyarylene sulfide (A) is heated with a compound (B) described later to produce a polyarylene sulfide copolymer, the polyarylene sulfide (A) preferably contains, as a functional group, at least one functional group selected from an amino group, two carboxyl groups bonded to two adjacent carbon atoms, and an acid anhydride group derived from the two carboxyl groups. Furthermore, from the viewpoint of reactivity, the combination of the functional group of the polyarylene sulfide (A) and the functional group of the compound (B) is preferably a combination of an amino group and an acid anhydride group, and therefore, the polyarylene sulfide (A) preferably contains an amino group and / or an acid anhydride group. In particular, from the viewpoint of ease of polymerization reaction when producing the polyarylene sulfide (A) by the production method described below, the functional group of the polyarylene sulfide (A) is preferably an amino group, and accordingly, the functional group of the compound (B) is preferably an acid anhydride group. The position of the functional group of the polyarylene sulfide (A) may be in the main chain of the polyarylene sulfide or at the terminal, but introduction at the terminal is preferred because it is easier to control the reaction with other polymers or compounds having functional groups, and is also preferred from the viewpoint of copolymerization reaction with the compound (B) as described below. When the functional group is introduced at the terminal, it is preferably in the p-position relative to the S bonded to Ar. In addition, polyarylene sulfides having the functional group bonded to Ar can also be exemplified as preferred embodiments. The functional group is a structure derived from the compound (C) described below, and details thereof will be described later.

[0058] The lower limit of the amount of functional groups contained in the polyarylene sulfide (A) is preferably 400 μmol / g or more, more preferably 500 μmol / g or more, and even more preferably 700 μmol / g or more. When the amount of functional groups is equal to or greater than the above lower limit, the glass transition temperature of the resulting polyarylene sulfide copolymer tends to be sufficiently high. Furthermore, the upper limit of the amount of functional groups is preferably 5,000 μmol / g or less, more preferably 4,000 μmol / g or less, and even more preferably 3,000 μmol / g or less. When the amount of functional groups is equal to or less than the above upper limit, a decrease in the chemical resistance of the polyarylene sulfide copolymer tends to be prevented when producing the polyarylene sulfide copolymer described below. Note that when the functional groups are two carboxyl groups bonded to two adjacent carbon atoms, respectively, the functional groups refer to the amount of acid anhydride groups generated from the two carboxyl groups bonded to two adjacent carbon atoms, respectively. The functional group in the polyarylene sulfide is determined by FT-IR analysis of the polyarylene sulfide, for example, 1901m derived from a benzene ring. －１ The absorption at 3382 cm originating from the amino group －１ The absorption intensity of 1901 m from the benzene ring －１ The absorption at 1860 cm originating from the acid anhydride group －１ It can be quantified by comparing the intensity of absorption.

[0059] The number average molecular weight of the polyarylene sulfide (A) is preferably 1,000 or more, more preferably 2,000 or more. When the number average molecular weight of the polyarylene sulfide (A) is 1,000 or more, the chemical resistance of the resulting polyarylene sulfide copolymer is enhanced. The upper limit of the number average molecular weight of the polyarylene sulfide (A) is preferably 10,000 or less, more preferably 6,000 or less, and even more preferably 4,000 or less. When the number average molecular weight of the polyarylene sulfide is 10,000 or less, the heat resistance of the resulting polyarylene sulfide copolymer is enhanced. The number average molecular weight is a value calculated in terms of polystyrene by gel permeation chromatography (GPC), a type of size exclusion chromatography (SEC).

[0060] The method for producing polyarylene sulfide (A) will be described in detail below, but is not limited to the following method. In the present invention, a method for producing polyarylene sulfide by reacting at least a dihalogenated aromatic compound, an inorganic sulfidizing agent, and compound (C) in an organic polar solvent in the presence of an alkali metal hydroxide is preferred, in which compound (C) is present in a reaction vessel in an amount of 0.04 mol to 0.5 mol per mol of inorganic sulfidizing agent. Compound (C) will be described later. Furthermore, when two carboxyl groups bonded to two adjacent carbon atoms or acid anhydride groups derived from these two carboxyl groups are selected as functional groups contained in polyarylene sulfide (A), it is also effective to employ a known method for producing polyarylene sulfide by reacting at least a dihalogenated aromatic compound, an inorganic sulfidizing agent, and a monohalogenated compound in an organic polar solvent in the presence of an alkali metal hydroxide, from the viewpoint of the reactivity of the monohalogenated compound, i.e., the ease of introducing functional groups into polyarylene sulfide (A). Examples of the monohalogenated compound used here include 3-chlorophthalic acid and 4-chlorophthalic acid.

[0061] [Inorganic Sulfidizing Agent] The inorganic sulfidizing agent used in the production method of polyarylene sulfide (A) may be any agent capable of introducing a sulfide bond into a dihalogenated aromatic compound, and examples thereof include alkali metal sulfides, alkali metal hydrosulfides, and hydrogen sulfide.

[0062] Specific examples of alkali metal sulfides include lithium sulfide, sodium sulfide, potassium sulfide, rubidium sulfide, cesium sulfide, and mixtures of two or more of these. Among these, lithium sulfide and / or sodium sulfide are preferred, with sodium sulfide being more preferred. These alkali metal sulfides can be used as hydrates, aqueous mixtures, or anhydrous forms. An aqueous mixture refers to an aqueous solution, a mixture of an aqueous solution and a solid component, or a mixture of water and a solid component. Generally available, inexpensive alkali metal sulfides are hydrates or aqueous mixtures, so it is preferable to use alkali metal sulfides in these forms.

[0063] Specific examples of alkali metal hydrosulfides include lithium hydrosulfide, sodium hydrosulfide, potassium hydrosulfide, rubidium hydrosulfide, cesium hydrosulfide, and mixtures of two or more of these. Among these, lithium hydrosulfide and / or sodium hydrosulfide are preferred, and sodium hydrosulfide is more preferred.

[0064] Alternatively, an alkali metal sulfide prepared in a reaction system from an alkali metal hydrosulfide and an alkali metal hydroxide can be used. Alternatively, an alkali metal sulfide prepared in advance by contacting an alkali metal hydrosulfide with an alkali metal hydroxide can be used. These alkali metal hydrosulfides and alkali metal hydroxides can be used as hydrates, aqueous mixtures, or anhydrous forms. Hydrates or aqueous mixtures are preferred from the standpoints of availability and cost.

[0065] Furthermore, alkali metal sulfides prepared in the reaction system from an alkali metal hydroxide such as lithium hydroxide or sodium hydroxide and hydrogen sulfide can also be used.Alkali metal sulfides prepared in advance by contacting an alkali metal hydroxide such as lithium hydroxide or sodium hydroxide with hydrogen sulfide can also be used.Hydrogen sulfide may be used in any form, whether gaseous, liquid, or aqueous solution.

[0066] [Compound (C)] The compound (C) used in the production method of the polyarylene sulfide (A) is a compound having at least one aromatic ring and, on the one aromatic ring, at least one functional group selected from two carboxyl groups bonded to two adjacent carbon atoms, respectively, or an acid anhydride group derived from the two carboxyl groups, an amino group, a hydroxyl group, a carboxyl group, a silanol group, a sulfonic acid group, an acetamide group, a sulfonamide group, a cyano group, an isocyanate group, an aldehyde group, an acetyl group, an epoxy group, and an alkoxysilyl group, and at least one functional group selected from a hydroxyl group, a salt of a hydroxyl group, a thiol group, and a salt of a thiol group. At least one functional group selected from two carboxyl groups bonded to two adjacent carbon atoms, or an acid anhydride group derived from the two carboxyl groups, an amino group, a hydroxyl group, a carboxyl group, a silanol group, a sulfonic acid group, an acetamide group, a sulfonamide group, a cyano group, an isocyanate group, an aldehyde group, an acetyl group, an epoxy group, and an alkoxysilyl group, is introduced into the polyarylene sulfide (A) as a functional group in the polymerization reaction step. At least one functional group selected from a hydroxyl group, a salt of a hydroxyl group, a thiol group, and a salt of a thiol group reacts with a dihalogenated aromatic compound in the polymerization reaction step.

[0067] From the viewpoint of reactivity when polyarylene sulfide (A) is heated with compound (B) described below, the functional group introduced into polyarylene sulfide (A) in compound (C) is preferably at least one functional group selected from an amino group, two carboxyl groups bonded to two adjacent carbon atoms, and an acid anhydride group derived from the two carboxyl groups, and more preferably an amino group and / or an acid anhydride group. Specific examples of compound (C) having such a functional group include 2-aminophenol, 4-aminophenol, 3-aminophenol, 2-aminothiophenol, 4-aminothiophenol, 3-aminothiophenol, 3-hydroxyphthalic acid, 4-hydroxyphthalic acid, 3-mercaptophthalic acid, 4-mercaptophthalic acid, and compounds in which the hydroxyl group or thiol group of these compounds is an alkali metal or alkaline earth metal salt. Of these, 4-aminophenol and 4-aminothiophenol are preferred compounds from the viewpoint of reactivity. It should be noted that two or more different compounds (C) may be used in combination as long as they have the above characteristics. When a compound having a hydroxyl group or a thiol group is used as the compound (C), it is a preferred embodiment to simultaneously use an equivalent amount of an alkali metal hydroxide. Also, when a compound in which the hydroxyl group or the thiol group is in the form of a salt is used as the compound (C), it is possible to form the salt in advance and then use it to produce polyarylene sulfide, or it is possible to form the salt by reaction in a reaction vessel.

[0068] The lower limit of the amount of compound (C) used in the polymerization reaction is preferably 0.01 mol or more per mol of the inorganic sulfidizing agent added, more preferably 0.02 mol or more, even more preferably 0.04 mol or more, even more preferably 0.05 mol or more, even more preferably 0.06 mol or more, even more preferably 0.08 mol or more, and particularly preferably 0.1 mol or more. A use amount of this value or more is preferred because functional groups can be sufficiently introduced into the polyarylene sulfide (A). Furthermore, the upper limit of the use amount of compound (C) is preferably 0.5 mol or less per mol of the inorganic sulfidizing agent added, more preferably 0.45 mol or less, and even more preferably 0.4 mol or less. A use amount of this value or less is preferred because it prevents a decrease in the molecular weight of the polyarylene sulfide (A).

[0069] The timing of adding compound (C) is not particularly specified, and compound (C) may be added at any time during the pre-processing step described below, at the start of polymerization, or during the polymerization reaction step, or may be added in multiple batches. However, from the viewpoint of efficiently reacting compound (C) with the dihalogenated aromatic compound, it is more preferable to add compound (C) at the same stage as the addition of the dihalogenated aromatic compound to the reaction vessel.

[0070] [Dihalogenated Aromatic Compound] Examples of the dihalogenated aromatic compound used in the production method of polyarylene sulfide (A) include dihalogenated benzenes such as p-dichlorobenzene, o-dichlorobenzene, m-dichlorobenzene, p-dibromobenzene, o-dibromobenzene, m-dibromobenzene, 1-bromo-4-chlorobenzene, and 1-bromo-3-chlorobenzene, as well as dihalogenated aromatic compounds including compounds having substituents other than halogen, such as 1-methoxy-2,5-dichlorobenzene, 1-methyl-2,5-dichlorobenzene, 1,4-dimethyl-2,5-dichlorobenzene, 1,3-dimethyl-2,5-dichlorobenzene, 2,5-dichlorobenzoic acid, 3,5-dichlorobenzoic acid, 2,5-dichloroaniline, 3,5-dichloroaniline, and bis(4-chlorophenyl)sulfide. Among these, dihalogenated aromatic compounds mainly composed of p-dihalogenated benzenes, typified by p-dichlorobenzene, are preferred. Particularly preferably, the dihalogenated aromatic compound contains p-dichlorobenzene in an amount of 80 to 100 mol %, and even more preferably 90 to 100 mol %. It is also possible to use a combination of two or more different dihalogenated aromatic compounds.

[0071] Although there is no particular lower limit to the amount of dihalogenated aromatic compound used, the [monomer ratio] expressed by the following formula is preferably 0.8 or more, more preferably 0.9 or more, and even more preferably 0.95 or more. By setting the [monomer ratio] within the above range, the polymerization reaction system can be stabilized and side reactions can be prevented, which is preferable. Furthermore, there is no particular upper limit to the amount used, but the [monomer ratio] is preferably 1.2 or less, more preferably 1.1 or less, and even more preferably 1.05 or less. By setting the [monomer ratio] within the above range, the amount of halogen remaining in the polyarylene sulfide can be reduced, which is preferable. In the following formula, the [amount of dihalogenated aromatic compound substance], [amount of inorganic sulfidizing agent substance], and [amount of compound (C) substance] represent the amount (moles) of each compound used when producing polyarylene sulfide. [Monomer ratio] = [amount of dihalogenated aromatic compound substance] / ([amount of inorganic sulfidizing agent substance] + [amount of compound (C) substance]).

[0072] [Organic Polar Solvent] Preferred examples of organic polar solvents include organic amide solvents. Specific examples include N-alkylpyrrolidones such as N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, and N-cyclohexyl-2-pyrrolidone; caprolactams such as N-methyl-ε-caprolactam; aprotic organic solvents such as 1,3-dimethyl-2-imidazolidinone, N,N-dimethylacetamide, N,N-dimethylformamide, and hexamethylphosphoric triamide; and mixtures thereof, which are preferably used due to their high reaction stability. Among these, N-methyl-2-pyrrolidone and 1,3-dimethyl-2-imidazolidinone are preferred, and N-methyl-2-pyrrolidone is more preferred.

[0073] The amount of organic polar solvent used is preferably 2.0 mol or more, more preferably 2.2 mol or more, and even more preferably 2.3 mol or more, per mol of inorganic sulfidizing agent charged. A use amount of this value or more is preferred because polyarylene sulfide can be synthesized in good yield. Furthermore, the amount of organic polar solvent used is preferably 6.0 mol or less, more preferably 5.0 mol or less, and even more preferably 4.0 mol or less, per mol of inorganic sulfidizing agent charged. A use amount of this value or less is preferred because gas generation when the resulting polyarylene sulfide is heated can be reduced.

[0074] [Polymerization Aid] In order to obtain a polyarylene sulfide with a relatively high degree of polymerization in a shorter time, it is also a preferred embodiment to use a polymerization aid. Here, the polymerization aid refers to a substance that has the effect of increasing the viscosity of the resulting polyarylene sulfide. Specific examples of such polymerization aids include organic carboxylates, water, alkali metal chlorides, organic sulfonates, alkali metal sulfates, alkaline earth metal oxides, alkali metal phosphates, and alkaline earth metal phosphates. These may be used alone or in combination of two or more. Among these, organic carboxylates, water, and alkali metal chlorides are preferred, and alkali metal carboxylates are preferred as organic carboxylates, and lithium chloride is preferred as alkali metal chlorides.

[0075] The alkali metal carboxylate is a salt of a carboxylate represented by the general formula R(COOM) ｎ (wherein R is an alkyl group, cycloalkyl group, aryl group, alkylaryl group, or arylalkyl group having 1 to 20 carbon atoms; M is an alkali metal selected from lithium, sodium, potassium, rubidium, and cesium; and n is an integer of 1 to 3). The alkali metal carboxylate can also be used as a hydrate, anhydrous form, or aqueous solution. Specific examples of the alkali metal carboxylate include lithium acetate, sodium acetate, potassium acetate, sodium propionate, lithium valerate, sodium benzoate, and mixtures thereof.

[0076] Alkali metal carboxylates may be synthesized by adding and reacting an organic acid with one or more compounds selected from the group consisting of alkali metal hydroxides, alkali metal carbonates, and alkali metal bicarbonates in approximately equal chemical equivalents. Among the alkali metal carboxylates, lithium salts are highly soluble in the reaction system and have a significant auxiliary effect, but are expensive. On the other hand, potassium, rubidium, and cesium salts are thought to have insufficient solubility in the reaction system, so sodium acetate, which is inexpensive and has adequate solubility in the polymerization system, is most preferably used.

[0077] When these alkali metal carboxylates are used as a polymerization aid, the amount used is usually preferably in the range of 0.01 mol to 2 mol per mol of the charged inorganic sulfidizing agent, more preferably in the range of 0.1 mol to 0.6 mol, and even more preferably in the range of 0.2 mol to 0.5 mol, in terms of obtaining a higher degree of polymerization.

[0078] When water is used as a polymerization aid, the amount added is usually preferably in the range of 0.3 mol to 15 mol per mol of the charged inorganic sulfidizing agent, more preferably in the range of 0.6 mol to 10 mol, and even more preferably in the range of 1 mol to 5 mol, in terms of obtaining a higher degree of polymerization.

[0079] Of course, two or more of these polymerization aids can be used in combination. For example, when an alkali metal carboxylate and water are used in combination, a higher molecular weight can be achieved with smaller amounts of the alkali metal carboxylate and water.

[0080] The timing of addition of these polymerization aids is not particularly specified, and they may be added at any time during the pre-step, at the start of polymerization, or during the polymerization reaction step described below, or may be added in multiple batches. When an alkali metal carboxylate is used as the polymerization aid, it is more preferable to add it simultaneously with other additives at the start of the pre-step or at the start of polymerization, from the viewpoint of ease of addition. When water is used as the polymerization aid, it is effective to add it during the polymerization reaction step after charging the dihalogenated aromatic compound.

[0081] [Polymerization Stabilizer] Polymerization stabilizers can be used to stabilize the polymerization reaction system and prevent side reactions. Polymerization stabilizers contribute to stabilizing the polymerization reaction system and suppress undesirable side reactions. One indicator of side reactions is the formation of thiophenol. The addition of a polymerization stabilizer can suppress the formation of thiophenol. Specific examples of polymerization stabilizers include compounds such as alkali metal hydroxides, alkali metal carbonates, alkaline earth metal hydroxides, and alkaline earth metal carbonates. Among these, alkali metal hydroxides such as sodium hydroxide, potassium hydroxide, and lithium hydroxide are preferred. The aforementioned alkali metal carboxylates also function as polymerization stabilizers and are therefore classified as polymerization stabilizers. Furthermore, when using an alkali metal hydrosulfide as an inorganic sulfidizing agent, it is particularly preferable to use an alkali metal hydroxide simultaneously. However, an excess amount of alkali metal hydroxide relative to the sulfidizing agent can also serve as a polymerization stabilizer.

[0082] These polymerization stabilizers can be used alone or in combination of two or more. The polymerization stabilizer is preferably used in an amount of 0.02 to 0.2 mol, more preferably 0.03 to 0.1 mol, and even more preferably 0.04 to 0.09 mol, per mol of the charged inorganic sulfidizing agent. If this amount is too small, the stabilizing effect is low, and conversely, if it is too large, it is economically disadvantageous and the polymer yield tends to decrease.

[0083] The timing of adding the polymerization stabilizer is not particularly specified, and it may be added at any time during the pre-process, at the start of polymerization, or during the polymerization reaction process described below, or may be added in multiple batches. However, it is more preferable to add it simultaneously at the start of the pre-process or at the start of polymerization, as this is easier.

[0084] Next, a preferred method for producing polyarylene sulfide will be specifically explained in order, including a pre-process, a polymerization reaction process, a recovery process, and a post-treatment process, but the method is not limited to this method.

[0085] [Pre-step] In the production method of polyarylene sulfide (A), the inorganic sulfidizing agent is usually used in the form of a hydrate. Before adding the dihalogenated aromatic compound, it is preferable to raise the temperature of a mixture containing an organic polar solvent and the inorganic sulfidizing agent and remove excess water from the system.

[0086] As described above, inorganic sulfidizing agents can also be used that are prepared in situ in the reaction system from an alkali metal hydrosulfide and an alkali metal hydroxide, or in a vessel separate from the polymerization vessel. While there are no particular limitations on this method, a preferred example is a method in which an alkali metal hydrosulfide and an alkali metal hydroxide are added to an organic polar solvent under an inert gas atmosphere at a temperature ranging from room temperature to 150°C, preferably from room temperature to 100°C, and the mixture is heated to at least 150°C or higher, preferably 180°C to 260°C, under atmospheric pressure or reduced pressure, to distill off water. At this stage, a polymerization aid or compound (C) may be added. Toluene or the like may be added to promote the distillation of water during the reaction.

[0087] The amount of water in the system at the end of the pre-step, i.e., before the polymerization reaction step, is preferably 0.3 mol to 10.0 mol per mol of the charged sulfidizing agent. Here, the amount of water in the system is the amount of water charged into the polymerization system minus the amount of water removed from the polymerization system. The charged water may be in any form, such as water, an aqueous solution, or water of crystallization.

[0088] [Polymerization Reaction Step] Polyarylene sulfide (A) is produced by reacting at least an inorganic sulfidizing agent, a dihalogenated aromatic compound, and compound (C) in an organic polar solvent within a temperature range of 200°C or higher but lower than 290°C.

[0089] When starting the polymerization reaction step, the organic polar solvent, the sulfidizing agent, and the dihalogenated aromatic compound are mixed, desirably in an inert gas atmosphere, at a temperature ranging from room temperature to 240°C, preferably from 100°C to 230°C. Compound (C) and a polymerization aid may be added at this stage. These raw materials may be charged in any order, or simultaneously.

[0090] The mixture is heated to a temperature generally within the range of 200° C. to less than 290° C. There are no particular limitations on the rate of temperature increase, but a rate of 0.01° C. / min to 5° C. / min is usually selected, with a range of 0.1° C. / min to 3° C. / min being more preferred.

[0091] In general, the temperature is finally raised to a temperature of 250° C. to less than 290° C., and the reaction is carried out at that temperature for usually 0.25 to 50 hours, preferably 0.5 to 20 hours.

[0092] A method in which, before reaching the final temperature, the reaction is carried out for a certain period of time at, for example, 200° C. to 260° C., and then the temperature is raised to 270° C. to less than 290° C. is effective in obtaining a higher degree of polymerization. In this case, the reaction time at 200° C. to 260° C. is usually selected from the range of 0.25 to 20 hours, preferably 0.25 to 10 hours.

[0093] In order to adjust the molecular weight of the polymer, it is possible to add compound (C) during the polymerization. However, from the viewpoint of efficient reaction of compound (C), it is more preferable to add at least a part of compound (C) at the same stage as the dihalogenated aromatic compound.

[0094] [Recovery Step] In the method for producing the polyarylene sulfide (A), after the polymerization is completed, a solid is recovered from the polymerization reaction product containing the polymer, the solvent, etc. Any known method may be used for the recovery method.

[0095] For example, a method may be used in which the particulate polymer is recovered by slow cooling after the completion of the polymerization reaction. The slow cooling rate is not particularly limited, but is usually about 0.1°C / min to 3°C / min. It is not necessary to slow cool at the same rate throughout the entire slow cooling step; a method may be employed in which the polymer is slowly cooled at a rate of 0.1°C / min to 1°C / min until the polymer particles crystallize and precipitate, and then slowly cooled at a rate of 1°C / min or more.

[0096] Another preferred method is to carry out the recovery under rapid cooling conditions. Among these recovery methods, a flash method is preferred. In the flash method, the polymerization reaction product is subjected to high temperature and high pressure (usually 250°C or higher, 8 kg / cm ２This method involves flashing the polymer from a state of (above) into an atmosphere of normal pressure or reduced pressure, recovering the solvent and simultaneously recovering the polymer in powder form. The term "flashing" as used herein means ejecting the polymerization product from a nozzle. Specific examples of the flashing atmosphere include nitrogen or water vapor at normal pressure, and the temperature is usually selected from the range of 150°C to 250°C.

[0097] [Post-treatment step] After the polyarylene sulfide is produced through the above-mentioned polymerization reaction step and recovery step, it can be subjected to a post-treatment step of acid treatment, hot water treatment, or washing with an organic solvent. From the viewpoint of removing impurities, the post-treatment step is preferably any one of acid treatment, hot water treatment, and washing with an organic solvent, and more preferably two or more types of treatments are used in combination.

[0098] The acid treatment is carried out as follows. The acid used in the acid treatment is not particularly limited as long as it does not have the effect of decomposing the polyarylene sulfide (A), and examples thereof include acetic acid, hydrochloric acid, sulfuric acid, phosphoric acid, silicic acid, carbonic acid, and propylic acid. Among these, an acid selected from acetic acid and hydrochloric acid is more preferably used. On the other hand, acids that decompose or deteriorate the polyarylene sulfide (A), such as nitric acid, are not preferred. As a method for acid treatment, for example, a method of immersing the polyarylene sulfide (A) in an acid or an aqueous solution of an acid can be used, and stirring or heating can also be performed if necessary. When an acid solution is used, the solution may be a solution using an organic solvent or an aqueous solution, but an aqueous solution is preferred from the viewpoints of the tendency for the miscibility of the acid and the solubility of salts and basic components contained in the polyarylene sulfide to be relatively high. The water used is preferably distilled water or deionized water so as not to impair the effect of the desirable chemical modification of the polyarylene sulfide. For example, when acetic acid is used, a sufficient effect can be obtained by immersing the polyarylene sulfide (A) powder in an aqueous acetic acid solution of pH 4 heated to 80°C to 200°C and stirring for 30 minutes. The pH after treatment may be 4 or higher, for example, about pH 4 to 8. In order to remove residual acid or salt from the acid-treated polyarylene sulfide (A), it is preferable to further wash the polyarylene sulfide (A) several times with water or warm water. The water used for washing is preferably distilled water or deionized water so as not to impair the desired chemical modification effect of the polyarylene sulfide (A). When performing acid treatment, when a polyarylene sulfide copolymer is obtained using the polyarylene sulfide (A), a polyarylene sulfide copolymer with a higher molecular weight tends to be obtained, which is preferable.

[0099] The hot water treatment is carried out as follows. When treating polyarylene sulfide (A) with hot water, the temperature of the hot water is preferably 100°C or higher, more preferably 120°C or higher, even more preferably 150°C or higher, and particularly preferably 170°C or higher. Temperatures below 100°C are not preferred because the desired chemical modification effect of polyarylene sulfide is small. In order to achieve the desired chemical modification effect of polyarylene sulfide (A) by hot water treatment, it is preferable that the water used is distilled water or deionized water. There are no particular restrictions on the operation of the hot water treatment. The hot water treatment can be carried out by adding a predetermined amount of polyarylene sulfide (A) to a predetermined amount of water, heating and stirring in a pressure vessel, or by continuously performing hot water treatment. The ratio of polyarylene sulfide (A) to water is preferably higher, but a bath ratio (weight of cleaning solution relative to the weight of dry polyarylene sulfide (A)) of 200 g or less of polyarylene sulfide (A) per liter of water is usually selected. In addition, in order to avoid undesirable decomposition of the reactive functional groups at the terminals, it is desirable to carry out the treatment in an inert atmosphere. Furthermore, in order to remove remaining components, it is preferable to wash the polyarylene sulfide (A) after this hot water treatment operation with warm water several times.

[0100] Washing with an organic solvent is as follows. There are no particular limitations on the organic solvent used to wash the polyarylene sulfide (A), as long as it does not have the effect of decomposing the polyarylene sulfide. Examples of organic solvents that can be used to wash the polyarylene sulfide (A) include nitrogen-containing polar solvents such as N-methyl-2-pyrrolidone, dimethylformamide, and dimethylacetamide; sulfoxide / sulfone solvents such as dimethyl sulfoxide, dimethyl sulfone, and sulfolane; ketone solvents such as acetone, methyl ethyl ketone, diethyl ketone, and acetophenone; ether solvents such as dimethyl ether, dipropyl ether, dioxane, and tetrahydrofuran; halogenated solvents such as chloroform, methylene chloride, trichloroethylene, ethylene dichloride, and perchloroethylene; alcohol solvents such as methanol, ethanol, propanol, butanol, pentanol, ethylene glycol, and propylene glycol; and aromatic hydrocarbon solvents such as benzene, toluene, and xylene. Among these organic solvents, N-methyl-2-pyrrolidone, acetone, dimethylformamide, and chloroform are preferred. Furthermore, from the viewpoint of removing impurities having an arylene sulfide structure, solvents selected from N-methyl-2-pyrrolidone, dimethylformamide, and chloroform, which are nitrogen-containing polar solvents that tend to provide relatively high solubility, are particularly preferred. These organic solvents may be used alone or in combination with two or more, or may be mixed with water. Examples of methods for washing with an organic solvent include immersing the polyarylene sulfide (A) in the organic solvent, with appropriate stirring or heating, if necessary. There are no particular limitations on the washing temperature when washing the polyarylene sulfide (A) with an organic solvent, and any temperature from room temperature to approximately 300°C can be selected. While higher washing temperatures tend to increase the washing efficiency, a washing temperature of room temperature to 150°C is usually sufficient. Washing can also be performed under pressure in a pressure vessel at a temperature above the boiling point of the organic solvent. There are also no particular limitations on the washing time. Although depending on the washing conditions, in the case of batch washing, sufficient effects can usually be obtained by washing for 5 minutes or more. Continuous washing is also possible.The organic solvent is preferred because it reduces the amount of gas generated when the polyarylene sulfide (A) is heated, and also because it tends to facilitate the production of a high molecular weight product when the polyarylene sulfide (A) is used to produce a polyarylene sulfide copolymer, which will be described later.

[0101] [Thermal Oxidation Crosslinking Treatment] After the completion of polymerization, the polyarylene sulfide (A) can be used after being subjected to a thermal oxidative crosslinking treatment in which the polyarylene sulfide (A) is heated in an oxygen atmosphere or in the presence of a crosslinking agent such as a peroxide, thereby increasing the molecular weight thereof. However, the number average molecular weight of the polyarylene sulfide (A) is preferably 10,000 or less.

[0102] [Compound (B)] Compound (B) is a compound for producing a polyarylene sulfide copolymer by reacting it with polyarylene sulfide (A). Compound (B) is at least one compound selected from the formulae (a') to (u'). X is at least one selected from two carboxyl groups bonded to two adjacent carbon atoms, respectively, or an acid anhydride group derived from the two carboxyl groups, an amino group, a hydroxyl group, a carboxyl group, a silanol group, a sulfonic acid group, an acetamide group, a sulfonamide group, a cyano group, an isocyanate group, an aldehyde group, an acetyl group, an epoxy group, and an alkoxysilyl group. R ３ , R ４ , and R ５ are each a substituent selected from hydrogen, an alkyl group having 1 to 12 carbon atoms, an arylene group having 6 to 24 carbon atoms, and a halogen group; R ３ , R ４ , and R ５may be the same or different. From the viewpoint of ease of availability, hydrogen, a methyl group, an ethyl group, or a propyl group is preferred. Furthermore, the aromatic ring of each compound may be di- or tri-substituted, and the multiple substituents X substituted on one aromatic ring may be the same or different. From the viewpoint of reactivity when the above-mentioned polyarylene sulfide (A) and compound (B) are heated, it is preferable that compound (B) contains at least one functional group selected from an amino group, two carboxyl groups bonded to two adjacent carbon atoms, and an acid anhydride group derived from the two carboxyl groups as a functional group. Furthermore, from the viewpoint of reactivity, the combination of the functional group of polyarylene sulfide (A) and the functional group of compound (B) is more preferably an amino group and an acid anhydride group, and therefore it is more preferable that compound (B) contains an amino group and / or an acid anhydride group. In particular, from the viewpoint of ease of polymerization reaction when producing polyarylene sulfide (A) by the above-mentioned production method, it is preferable that the functional group of polyarylene sulfide (A) is an amino group, and accordingly it is preferable that the functional group of compound (B) is an acid anhydride group.

[0103] Specific examples of compound (B) include pyromellitic acid, 3,3',4,4'-thiodiphthalic acid, 3,3',4,4'-sulfonyldiphthalic acid, 3,3',4,4'-benzophenonetetracarboxylic acid, 3,3',4,4'-sulfinyldiphthalic acid, 3,3',4,4'-biphenyltetracarboxylic acid, 3,3',4,4'-tetracarboxyldiphenylmethane, 9,9-bis(3,4-dicarboxyphenyl)fluorene, naphthalene-1,4,5,8-tetracarboxylic acid, and bicyclo[2.2.2]oct-7-ene-2,3,5,6-tetracarboxylic acid. Carboxylic acid, 3,4,9,10-perylenetetracarboxylic acid, pyromellitic anhydride, 3,3',4,4'-thiodiphthalic anhydride, 3,3',4,4'-sulfonyldiphthalic anhydride, 3,3',4,4'-benzophenonetetracarboxylic dianhydride, 3,3',4,4'-sulfinyldiphthalic anhydride, 3,3',4,4'-biphenyltetracarboxylic dianhydride, 3,3',4,4'-tetracarboxyldiphenylmethane dianhydride, 9,9-bis(3,4-dicarboxyphenyl)fluorene dianhydride, naphthalene-1,4,5,8- Tetracarboxylic acid dianhydride, glycerin bisanhydrotrimellitate monoacetate, ethylene glycol bisanhydrotrimellitate, bicyclo[2.2.2]oct-7-ene-2,3,5,6-tetracarboxylic acid dianhydride, 3,4,9,10-perylenetetracarboxylic acid dianhydride, 4,4'-thiodibenzoic acid, 4,4'-dicarboxylbenzophenone, 4,4'-sulfinyldibenzoic acid, 4,4'-dicarboxylbiphenyl, p-phenylenediamine, 4,4'-diaminodiphenyl sulfide, 4,4'-diaminodiphenyl Sulfone, 4,4'-diaminobenzophenone, 4,4'-diaminodiphenylmethane, 4,4'-diaminodiphenyl ether, 2,7-diaminofluorene, o-toluidine, 1,5-diaminonaphthalene, p-benzenediol, 4,4'-dihydroxydiphenyl sulfide, 4,4'-dihydroxydiphenyl sulfone, 4,4'-dihydroxybenzophenone, 4,4'-dihydroxydiphenylmethane, 4,4'-dihydroxydiphenyl ether, 2,7-dihydroxyfluorene, 4,4'-dihydroxybiphenyl, 1,From the viewpoint of reactivity, compounds selected from 3,3',4,4'-thiodiphthalic anhydride, 3,3',4,4'-benzophenonetetracarboxylic dianhydride, 3,3',4,4'-sulfinyldiphthalic anhydride, 3,3',4,4'-biphenyltetracarboxylic dianhydride, 9,9-bis(3,4-dicarboxyphenyl)fluorene dianhydride, 4,4'-thiodibenzoic acid, 4,4'-dicarboxylbenzophenone, 4,4'-sulfinyldibenzoic acid, 4,4'-dicarboxylbiphenyl, pyromellitic acid, pyromellitic anhydride, 4,4'-diaminodiphenyl sulfone, 4,4'-diaminobenzophenone, and 2,7-diaminofluorene are preferably used.

[0104] [Production of Polyarylene Sulfide Copolymer] The polyarylene sulfide copolymer can be produced by heating the polyarylene sulfide (A) and the compound (B).

[0105] The ratio of the amount of functional groups derived from the compound (B) [μmol / g] to the amount of functional groups derived from the polyarylene sulfide (A) [μmol / g] is preferably 0.75 to 1.25. By setting it within this range, the resulting polyarylene sulfide copolymer tends to have a high molecular weight and exhibit sufficient mechanical properties and chemical resistance.

[0106] The polyarylene sulfide (A) and the compound (B) may be heated by mixing the entire amount from the beginning, or by mixing and heating at least a portion of the polyarylene sulfide (A) and at least a portion of the compound (B) and then heating the remaining polyarylene sulfide (A) and / or the compound (B). In the latter case, at least a portion of the polyarylene sulfide (A) and at least a portion of the compound (B) may be mixed and heated, and then the remaining polyarylene sulfide (A) and / or the compound (B) may be mixed and heated, or at least a portion of the polyarylene sulfide (A) and at least a portion of the compound (B) may be mixed and heated, and then the product may be removed, and then the remaining polyarylene sulfide (A) and / or the compound (B) may be mixed and heated. From the viewpoint of efficiently obtaining a polyarylene sulfide copolymer, it is preferable to mix and heat the entire amount of the polyarylene sulfide (A) and the compound (B) from the beginning. On the other hand, from the viewpoint of easily controlling and adjusting the thermal properties of the polyarylene sulfide copolymer, such as the glass transition temperature, crystallization temperature, and melting point, as well as the molecular weight, the type of terminal end and its amount depending on the application, it is preferable to mix and heat at least a part of the polyarylene sulfide (A) and at least a part of the compound (B), and then mix and heat the remaining polyarylene sulfide (A) and / or the compound (B).

[0107] The lower limit of the heating temperature can be, for example, 200°C or higher, preferably 230°C or higher, and more preferably 250°C or higher. By setting the lower limit of the heating temperature within this range, the reaction between the polyarylene sulfide (A) and the compound (B) can be easily promoted. By setting the heating temperature to a temperature at or above the melting point of the polyarylene sulfide (A), the reaction tends to be completed in a shorter time. The melting point of the polyarylene sulfide (A) cannot be uniquely determined because it varies depending on the composition and molecular weight of the polyarylene sulfide (A) and the heating environment, but it can be determined, for example, by analyzing the polyarylene sulfide (A) with a differential scanning calorimeter. The upper limit of the heating temperature can be, for example, 400°C or lower, preferably 380°C or lower, and more preferably 360°C or lower. By setting the upper limit of the heating temperature within this range, undesirable side reactions, such as crosslinking reactions and decomposition reactions between polyarylene sulfides (A), can be suppressed, and deterioration in the properties of the resulting polyarylene sulfide copolymer tends to be suppressed.

[0108] The heating time varies depending on the composition and molecular weight of the polyarylene sulfide (A) and the heating environment, so it cannot be uniquely specified, but it is preferable to set it so that the above-mentioned undesirable side reactions do not occur as much as possible. The lower limit of the heating time can be 0.1 minutes or more, for example, 1 minute or more, more preferably 2 minutes or more, and even more preferably 3 minutes or more. By setting the lower limit of the heating time in this range, the reaction between the polyarylene sulfide (A) and the compound (B) can be more sufficiently promoted. The upper limit of the heating time can be 100 hours or less, for example, 20 hours or less, more preferably 10 hours or less, and even more preferably 1 hour or less. Setting the upper limit of the heating time in this range tends to be economical and to avoid the above-mentioned undesirable side reactions.

[0109] Heating can be carried out in the absence or presence of a solvent. When heating is carried out in the presence of a solvent, the solvent is not particularly limited as long as it does not substantially cause undesirable side reactions such as decomposition or crosslinking of the produced polyarylene sulfide copolymer. One type of solvent or a mixture of two or more types can be used. On the other hand, from the viewpoint of efficiently obtaining the polyarylene sulfide copolymer, it is preferable to carry out the heating under substantially solvent-free conditions. Furthermore, from the viewpoint of preventing contamination of molded products by generated gases when molding the obtained polyarylene sulfide copolymer, it is also preferable to carry out the heating under substantially solvent-free conditions. Here, substantially solvent-free conditions refer to a system in which the polyarylene sulfide (A) and the compound (B) are heated, in which the solvent content is 10% by weight or less, preferably 3% by weight or less.

[0110] Heating in the method for producing the polyarylene sulfide copolymer of the present invention can be carried out by a method using a conventional polymerization reaction apparatus, and can also be carried out in a mold for producing a molded product, or by using an extruder or a melt kneader. Any method can be used without particular limitation as long as it uses an apparatus equipped with a heating mechanism, and known methods such as a batch method and a continuous method can be adopted.

[0111] The atmosphere during heating is preferably a non-oxidizing atmosphere, and it is also preferable to carry out the heating under reduced pressure conditions. Furthermore, when carrying out the heating under reduced pressure conditions, it is preferable to first change the atmosphere in the reaction system to a non-oxidizing atmosphere and then to a reduced pressure condition. This tends to suppress undesirable side reactions such as crosslinking reactions and decomposition reactions between polyarylene sulfides (A) or between the polyarylene sulfide copolymers produced. The non-oxidizing atmosphere refers to an atmosphere in which the oxygen concentration in the gas phase is 5% by volume or less, preferably 2% by volume or less, and more preferably an atmosphere substantially free of oxygen, i.e., an inert gas atmosphere such as nitrogen, helium, or argon. Among these, a nitrogen atmosphere is particularly preferable from the standpoint of economy and ease of handling. Furthermore, reduced pressure conditions refer to a pressure in the reaction system that is lower than atmospheric pressure, and the upper limit of the pressure is preferably 50 kPa or less, more preferably 20 kPa or less, and even more preferably 10 kPa or less. By setting the upper limit of the pressure in this range, undesirable side reactions such as crosslinking reactions tend to be suppressed. An example of the lower limit of the pressure is 0.1 kPa or more. By setting the lower limit of the pressure to 0.1 kPa or more, it is possible to avoid a load on the reaction apparatus caused by reducing the pressure more than necessary.

[0112] [Method for Producing Polyarylene Sulfide Copolymer Particles] The polyarylene sulfide copolymer particles can be produced by a process including step 1 of melt-kneading the polyarylene sulfide copolymer and a water-soluble thermoplastic resin, and step 2 of removing the water-soluble thermoplastic resin by washing with water or an alcohol.

[0113] [Step 1] [Water-Soluble Thermoplastic Resin] A water-soluble thermoplastic resin is used in the method for producing polyarylene sulfide copolymer particles of the present invention. There are no limitations on the water-soluble thermoplastic resin, but specific examples include polyalkylene glycol, polyvinyl alcohol, polyvinylpyrrolidone, polyamide, and polyamideimide. Polyalkylene glycol is preferred. In the present invention, the use of a water-soluble thermoplastic resin allows the use of water or alcohols in the cleaning process described below, preventing workers from being exposed to organic solvents. This is also preferred because it reduces the release of chemical substances into the environment. The water-soluble thermoplastic resin preferably has a 10% weight loss temperature of 300°C or higher. A 10% weight loss temperature of 300°C or higher is preferred because it reduces the amount of decomposition gas during the melt-kneading process with the polyarylene sulfide copolymer. The 10% weight loss temperature can be analyzed, for example, by thermogravimetry under a nitrogen stream. Examples of polymers with a 10% weight loss temperature of 300°C or higher include polyalkylene glycol and polyvinylpyrrolidone. Furthermore, it is preferable that the water-soluble thermoplastic resin is incompatible with the polyarylene sulfide copolymer during melt-kneading. Incompatibility refers to a state in which the two resins are not completely mixed at the molecular level, even if they appear to be kneaded at the macro level. For example, when the resin composition is washed with water or alcohols, the water-soluble thermoplastic resin is easily separated and removed, thereby obtaining polyarylene sulfide copolymer microparticles, which is preferable. When the water-soluble thermoplastic resin is compatible with the polyarylene sulfide copolymer, the two are integrated within the resin composition, and polyarylene sulfide copolymer microparticles cannot be obtained even when washed with water or alcohols. Whether or not they become incompatible depends on the kneading conditions and the composition of the polyarylene sulfide copolymer, so it is difficult to generalize. However, polyalkylene glycols are an example of a water-soluble thermoplastic resin that is likely to be incompatible with the polyarylene sulfide copolymer.

[0114] The form of the polyarylene sulfide copolymer used as the raw material for the polyarylene sulfide copolymer particles of the present invention is not particularly limited, and examples thereof include powder, pellets, fibers, films, molded products, granules, etc. Generally, dry grinding, wet grinding, and freeze grinding using a jet mill, bead mill, hammer mill, ball mill, cutter mill, stone-type grinder, etc. are known as methods for atomizing resins. However, when pellets or molded products are used as raw materials, these methods result in insufficient atomization, making it impossible to obtain particles of the desired particle size, and require long grinding times, resulting in problems such as reduced economy and productivity. However, the present method makes it possible to easily granulate even when pellets or molded products are used as raw materials.

[0115] The lower limit of the glass transition point of the polyarylene sulfide copolymer used in producing the polyarylene sulfide copolymer particles of the present invention is 95°C or higher, preferably 100°C or higher, and more preferably 110°C or higher. If the glass transition point is lower than 95°C, high rigidity cannot be obtained under high temperature conditions. The upper limit of the glass transition point is 190°C or lower, preferably 180°C or lower, and more preferably 160°C or lower. If the glass transition point exceeds 190°C, chemical resistance will be insufficient.

[0116] The glass transition points of the raw material polyarylene sulfide copolymer and polyarylene sulfide copolymer particles may vary depending on the conditions for producing polyarylene sulfide copolymer microparticles. The glass transition point of the polyarylene sulfide copolymer or polyarylene sulfide copolymer particles is defined as the inflection point of the baseline shift detected when the temperature is increased from 0°C to 340°C at a rate of 20°C / min using a differential scanning calorimeter according to the method described below.

[0117] The lower limit of the weight-average molecular weight of the polyarylene sulfide copolymer used to produce the polyarylene sulfide copolymer particles of the present invention is preferably 30,000 or more, more preferably 40,000 or more, and even more preferably 50,000 or more. A weight-average molecular weight of 30,000 or more tends to improve the mechanical properties of the polyarylene sulfide copolymer fine particles. There is no particular restriction on the upper limit of the molecular weight of the polyarylene sulfide copolymer particles, but examples of the weight-average molecular weight include 200,000 or less, preferably 150,000 or less, and more preferably 100,000 or less. When the upper limit of the weight-average molecular weight is in the above range, the moldability of the polyarylene sulfide copolymer particles tends to be excellent.

[0118] The weight-average molecular weight of the raw material polyarylene sulfide copolymer and the weight-average molecular weight of the polyarylene sulfide copolymer particles may change depending on the conditions for producing the polyarylene sulfide copolymer particles. The degree of change can be evaluated by the Mw retention, which is the percentage of the weight-average molecular weight of the polyarylene sulfide copolymer particles divided by the molecular weight of the polyarylene sulfide copolymer used in particle production. The Mw retention is preferably 50% or more, more preferably 60% or more, and even more preferably 80% or more. By keeping the Mw retention within the above range, the mechanical properties of the polyarylene sulfide copolymer particles can be maintained at a high level, which is preferable. The upper limit of the Mw retention is preferably 150% or less, more preferably 130% or less. If the Mw retention exceeds 150%, the viscosity increases and handling becomes difficult. As will be described later, the Mw retention rate varies depending on the stability of the polyarylene sulfide copolymer when the polyarylene sulfide copolymer is dissolved in a solvent in the dissolution step, and therefore can be adjusted by the type of solvent used and the amount of water.

[0119] [Polyalkylene glycol] A particularly preferred water-soluble thermoplastic resin used in the method for producing polyarylene sulfide copolymer particles of the present invention is polyalkylene glycol. There are no particular limitations on the polyalkylene glycol used in the present invention, but specific examples include polyethylene glycol, polypropylene glycol, polytetramethylene glycol, polypentamethylene glycol, polyhexamethylene glycol, polyethylene glycol-polytetramethylene glycol copolymers, and alkylphenyl ethers in which the hydroxyl groups at one or both ends of these are blocked with methyl, ethyl, propyl, isopropyl, butyl, hexyl, octyl, decyl, dodecyl, hexadecyl, octadecyl, or the like. Among these, polyethylene glycol or polypropylene glycol is preferred because of its ease of removal by washing, and polyethylene glycol is more preferred.

[0120] The lower limit of the weight-average molecular weight of the polyalkylene glycol is preferably 1,000 or more, more preferably 2,000 or more, and even more preferably 10,000 or more. The above range is preferable because a uniform dispersion state can be obtained when the polyalkylene glycol is melt-kneaded with the polyphenylene sulfide copolymer. The upper limit of the weight-average molecular weight of the polyalkylene glycol is preferably 1,000,000 or less, more preferably 800,000 or less, and even more preferably 500,000 or less. The above range is preferable because of ease of removal by washing.

[0121] The lower limit of the viscosity ratio ηa / ηb between the melt viscosity (ηa) of the polyarylene sulfide copolymer and the melt viscosity (ηb) of the water-soluble thermoplastic resin is preferably 0.1 or more, more preferably 1 or more. The upper limit is preferably 1000 or less, more preferably 500 or less, and even more preferably 300 or less. As the melt viscosity ratio ηa / ηb approaches 1, the particle size of the obtained particles tends to become smaller, but approaching 1 does not pose a problem in producing particles having a D50 particle size of 1 μm or more. Furthermore, it is preferable that the melt viscosity ratio ηa / ηb is not less than the above lower limit and not more than the above upper limit, because this allows the production of polyarylene sulfide copolymer particles having a D50 particle size of 1,000 μm or less.

[0122] The melt viscosity of the polyarylene sulfide copolymer and the water-soluble thermoplastic resin referred to here is a complex viscosity at 300° C. obtained by measuring dynamic viscoelasticity in a molten state.

[0123] The ratio of the polyarylene sulfide copolymer to the water-soluble thermoplastic resin is not limited as long as the polyarylene sulfide copolymer is well dispersed in the water-soluble thermoplastic resin, but the lower limit of the ratio is preferably 1 part by weight or more of the polyarylene sulfide copolymer per 100 parts by weight of the water-soluble thermoplastic resin, more preferably 10 parts by weight or more, and even more preferably 30 parts by weight or more. The above range is preferable from the viewpoint of economy and productivity. Furthermore, from the viewpoint of ensuring good dispersion of the polyarylene sulfide copolymer in the polyalkylene glycol during melt-kneading, the polyarylene sulfide copolymer is preferably 100 parts by weight or less of the polyarylene sulfide copolymer, more preferably 80 parts by weight or less, and even more preferably 50 parts by weight or less per 100 parts by weight of the polyalkylene glycol.

[0124] During melt-kneading, other components besides the polyarylene sulfide copolymer and the water-soluble thermoplastic resin may be blended, and other thermoplastic resins, antioxidants, compatibilizers, etc. may be included. Specific examples of other thermoplastic resins include vinyl chloride resin, vinylidene chloride resin, vinyl acetate resin, polyvinyl alcohol, polyvinyl acetal, polystyrene, AS resin, ABS resin, methacrylic resin, polyethylene, polypropylene, polyamide, polyacetal, polycarbonate, polyethylene terephthalate, polybutylene terephthalate, liquid crystal polyester resin, polyphenylene ether, polyphenylene sulfide, polyarylate, polysulfone, polyether sulfone, polyether imide, polyether ether ketone, fluororesin, and thermoplastic elastomer. The amount of other components is preferably 10 parts by weight or less, more preferably 5 parts by weight or less, per 100 parts by weight of the water-soluble thermoplastic resin.

[0125] In the method for producing polyarylene sulfide copolymer particles of the present invention, it is necessary to disperse the polyarylene sulfide copolymer in a water-soluble thermoplastic resin. For this purpose, it is preferable to heat a mixture of the polyarylene sulfide copolymer and the water-soluble thermoplastic resin. The required heating temperature varies depending on the molecular weight, structure, concentration, and solvent type of the polyarylene sulfide copolymer, but is usually preferably 250°C or higher, more preferably 270°C or higher, and even more preferably 300°C or higher. The upper limit is preferably 400°C or lower, more preferably 320°C or lower, from the viewpoint of suppressing decomposition of the polyarylene sulfide copolymer and the water-soluble thermoplastic resin.

[0126] The heating in this production method can be carried out by a method using a conventional polymerization reaction apparatus, and can also be carried out in a mold for producing a molded product, or by using an extruder or melt kneader. Any method using an apparatus equipped with a heating mechanism can be carried out without particular limitations, and known methods such as a batch method or a continuous method can be adopted. From the viewpoint of the dispersibility of the polyarylene sulfide copolymer in the water-soluble thermoplastic resin and productivity, a preferred example is a method of melt kneading using an extruder. It is preferable to carry out the melt kneading substantially under solvent-free conditions. "Substantially solvent-free" means that the solvent in the mixture is 10% by weight or less, more preferably 3% by weight or less.

[0127] The atmosphere during heating is preferably a non-oxidizing atmosphere, and it is also preferable to carry out the heating under reduced pressure conditions. Furthermore, when carrying out the heating under reduced pressure conditions, it is preferable to first change the atmosphere in the reaction system to a non-oxidizing atmosphere and then to a reduced pressure condition. A non-oxidizing atmosphere refers to an atmosphere in which the oxygen concentration in the gas phase is 5% by volume or less, preferably 2% by volume or less, and more preferably an atmosphere that is substantially free of oxygen, i.e., an inert gas atmosphere such as nitrogen, helium, or argon. Among these, a nitrogen atmosphere is particularly preferable from the standpoint of economy and ease of handling. Furthermore, reduced pressure conditions refer to a pressure in the reaction system that is lower than atmospheric pressure, and the upper limit of the pressure is preferably 50 kPa or less, more preferably 20 kPa or less, and even more preferably 10 kPa or less. Setting the upper limit of the pressure within this range tends to suppress undesirable side reactions such as crosslinking reactions. An example of a lower limit of the pressure is 0.1 kPa or more. Setting the lower limit of the pressure to 0.1 kPa or more can avoid the burden on the reaction apparatus caused by reducing the pressure more than necessary.

[0128] [Step 2] The production method of the present invention includes a step of melt-kneading the polyarylene sulfide copolymer and the water-soluble thermoplastic resin in step 1, washing the resulting mixture with a solvent in which the water-soluble thermoplastic resin is soluble, and removing the remaining polyarylene sulfide copolymer particles.

[0129] The polyarylene sulfide copolymer can be washed by a known method. As a washing method for removing deposits and inclusions from the polyarylene sulfide copolymer particles, reslurry washing or the like can be used, and heating may be used as appropriate.

[0130] The solvent used for washing is not limited as long as it does not dissolve the polyarylene sulfide copolymer particles but dissolves the water-soluble thermoplastic resin, but alcohols such as methanol, ethanol, and isopropanol, and water are preferred, with water being the most preferred. In particular, washing with water can minimize the exposure of workers to organic solvents during the granulation process, and is also preferred in that it can prevent environmental pollution due to the release of organic solvents into the environment. In addition, washing with water can prevent the organic solvent that acts as a plasticizer from remaining in the polyarylene sulfide copolymer particles, and is also preferred in that it can prevent the deterioration of mechanical properties when used as a raw material for three-dimensional objects or reinforced fiber composite substrates.

[0131] After the washing step, the polyarylene sulfide copolymer particles are isolated and dried. Examples of isolation methods include filtration, centrifugation, centrifugal filtration, heat drying, spray drying, and decantation. Drying is preferably carried out at a temperature below the melting point of the polyarylene sulfide copolymer particles, and may be carried out under reduced pressure. Examples of drying methods that can be selected include air drying, hot air drying, heat drying, reduced pressure drying, and freeze drying.

[0132] [Resin composition containing polyarylene sulfide copolymer particles] The polyarylene sulfide copolymer particles can be used as a resin composition by blending other optional components, such as a crystal nucleating agent, various fillers, and additives. When blending the polyarylene sulfide copolymer particles of the present invention with components selected from fillers and other additives, a more homogeneous resin composition can be obtained more efficiently than when using conventional polyarylene sulfide copolymer particles. In particular, when blending with a fibrous inorganic filler, the polyarylene sulfide copolymer particles can be blended more homogeneously. By molding such a resin composition containing the polyarylene sulfide copolymer particles of the present invention, a molded product with excellent mechanical properties can be obtained.

[0133] Examples of nucleating agents include talc, kaolin, organic phosphorus compounds, and polyether ether ketone. Examples of fillers include inorganic fillers and organic fillers. The type of filler is not limited, but considering the reinforcing effect of the filler in the resin composition, fibrous inorganic fillers such as glass fiber and carbon fiber are preferred. Carbon fiber not only improves mechanical properties but also reduces the weight of molded products. Furthermore, when the filler is carbon fiber, it is preferred because it more effectively improves the mechanical properties and chemical resistance of the resin composition. Examples of additives that can be used include antioxidants, mold release agents, lubricants, UV absorbers, colorants, and foaming agents.

[0134] [Uses of Polyarylene Sulfide Copolymer Particles] The polyarylene sulfide copolymer particles of the present invention, which have high heat resistance, high sphericity, and a specific median diameter D50, can be used in injection molding, injection compression molding, blow molding, extrusion molding, and the like, just like polyarylene sulfide copolymers. In addition, they can be used as heat-resistant additives in the fields of adhesive materials, coatings, and polymer compounds, and as raw materials for three-dimensionally molded objects produced by powder bed fusion. The three-dimensionally molded objects have excellent chemical resistance, high heat resistance, and excellent mechanical properties, which are derived from the properties of the polyarylene sulfide copolymer. Furthermore, due to the high fluidity of the polyarylene sulfide copolymer particles of the present invention, which have high sphericity, three-dimensionally molded objects molded from the polyarylene sulfide copolymer particles have uniform and sufficient molded object density and excellent surface quality.

[0135] A reinforced fiber composite substrate can also be obtained by a process of dispersing polyarylene sulfide copolymer particles in reinforcing fibers and a process of melting the polyarylene sulfide copolymer particles and impregnating the reinforcing fibers. This method involves dispersing the polyarylene sulfide copolymer particles in the gaps between the reinforcing fibers, melting the polyarylene sulfide copolymer particles, and applying pressure to impregnate the reinforcing fibers with the polyarylene sulfide copolymer. The reinforcing fibers may be continuous or discontinuous. The use of polyarylene sulfide copolymer particles enables the polyarylene sulfide copolymer to be dispersed efficiently and more uniformly in the gaps between the reinforcing fibers. During dispersion, the polyarylene sulfide copolymer particles can be dispersed directly into the reinforcing fibers, or they can be dispersed using a dispersion liquid described below. The highly heat-resistant and highly spherical polyarylene sulfide copolymer particles of the present invention exhibit uniform mechanical properties due to their excellent particle dispersibility. Such a reinforced fiber composite substrate is suitable for producing molded articles with high heat resistance.

[0136] The polyarylene sulfide copolymer particles of the present invention can also be used as a dispersion in which the polyarylene sulfide copolymer particles are dispersed in a liquid medium. Such a dispersion can be suitably used when producing a reinforced fiber composite substrate using the polyarylene sulfide copolymer particles. After dispersing the dispersion in reinforcing fibers and removing the medium by evaporation, the polyarylene sulfide copolymer particles can be melted and impregnated into the reinforcing fibers.

[0137] The liquid used as the medium for the dispersion is preferably water or an organic solvent. Specific examples of the organic solvent include alcohol compounds such as methanol, ethanol, 1-propanol, and 2-propanol; N-alkylpyrrolidones such as N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, and N-cyclohexyl-2-pyrrolidone; caprolactams such as N-methyl-ε-caprolactam; aprotic organic solvents such as 1,3-dimethyl-2-imidazolidinone, N,N-dimethylacetamide, N,N-dimethylformamide, and hexamethylphosphoric triamide; and organic solvents such as benzene, toluene, o-xylene, m-xylene, and p-xylene. Examples of suitable dispersion media include aromatic hydrocarbon compounds, ketone compounds such as 2-butanone, 3-pentanone, and 4-methyl-2-pentanone, and saturated aliphatic hydrocarbon compounds such as cyclopentane, pentane, isopentane, neopentane, methylcyclopentane, cyclohexane, n-hexane, 2-methylpentane, 3-methylpentane, 2,2-dimethylbutane, 2,3-dimethylbutane, methylcyclohexane, heptane, 2-methylhexane, 3-methylhexane, 2,3-dimethylpentane, 2,4-dimethylpentane, and ethylcyclohexane, as well as mixtures thereof. Water is the most preferred liquid medium. Dispersions can be stabilized using a dispersant, typically through entropic, ionic, or steric repulsion.

[0138] Three-dimensional objects molded from the polyarylene sulfide copolymer particles of the present invention, molded articles molded from resin compositions containing the polyarylene sulfide copolymer particles of the present invention, and molded articles molded from the reinforced fiber composite substrate of the present invention are excellent in heat resistance, chemical resistance, flame retardancy, electrical properties, and mechanical properties, and examples of their applications include electrical and electronic parts, audio equipment parts, household and office electrical appliance parts, machine-related parts, optical equipment, precision machinery-related parts, plumbing parts, automobile and vehicle-related parts, aircraft structural members, aircraft interior materials and other aerospace-related parts, as well as various other applications.

[0139] The method of the present invention will be explained in more detail below with reference to examples and comparative examples, but the present invention is not limited to these examples alone.

[0140] [Analysis of Functional Group Content] The amount of amino groups contained in polyarylene sulfide (A) was measured by using an FT-IR (IR-810 infrared spectrophotometer manufactured by JASCO Corporation) to prepare an amorphous film by rapidly cooling the polyarylene sulfide from a molten state obtained by heating at 320°C. －１ The absorption intensity at 3382 cm due to the amino group －１ The absorption intensity was calculated based on the

[0141] [Molecular Weight Measurement] The weight average molecular weight Mw and number average molecular weight Mn were measured using gel permeation chromatography (GPC), a type of size exclusion chromatography (SEC), and calculated in terms of polystyrene. The GPC measurement conditions are as follows: Apparatus: Senshu Scientific SSC-7110 Column name: Shodex UT806M x 2 Eluent: 1-chloronaphthalene Detector: Differential refractive index detector Column temperature: 210°C Pre-thermostat temperature: 250°C Pump thermostat temperature: 50°C Detector temperature: 210°C Flow rate: 1.0 mL / min Sample injection volume: 300 μL.

[0142] [Measurement of Melt Complex Viscosity] Measurement of the melt complex viscosity of the polyarylene sulfide copolymer before and after heat treatment, and measurement of the loss modulus and storage modulus for calculating the loss tangent were carried out using a rheometer under the following conditions: Apparatus: Anton Paar Physica MCR501 Plate: Parallel (φ25 mm) Gap: 1.0 mm Angular frequency (ω): 6.28 rad / sec Sample charge weight: Approximately 0.7 g Atmosphere: Under nitrogen gas flow at normal pressure Measurement temperature: 300°C.

[0143] [Measurement of Glass Transition Point, Melting Point, and Crystallization Temperature] The glass transition point (Tg), melting point (Tm), and crystallization temperature (Tmc) were measured by differential scanning calorimetry (DSC) using approximately 10 mg of an amorphous film prepared by quenching polyarylene sulfide copolymer particles or polyarylene sulfide copolymer pellets from a molten state. The inflection point of the baseline shift detected when the temperature was increased from 0°C to 340°C at a rate of 20°C / min was taken as the glass transition point. The crystallization temperature was determined as the crystallization peak temperature detected when the temperature was increased from 0°C to 340°C at a rate of 20°C / min, held at 340°C for 1 minute, and then cooled to 100°C at a rate of 20°C / min. The melting point was determined as the melting peak temperature detected when the sample was heated from 0°C to 340°C at a rate of 20°C / min, held at 340°C for 1 minute, cooled to 100°C at a rate of 20°C / min, held at 100°C for 1 minute, and then heated again to 340°C at a rate of 20°C / min. Apparatus: TA Instruments TA-Q200 Carrier gas: Nitrogen Sample purge flow rate: 50 mL / min.

[0144] [Particle size and particle size distribution in aqueous dispersion] A dispersion was prepared by adding approximately 100 mg of polyarylene sulfide copolymer particles or polyarylene sulfide particles to approximately 5 mL of deionized water in advance, and then adding Triton X-100 dropwise until the particles were dispersible. The dispersion was added to a laser diffraction particle size distribution analyzer (Microtrac MT3300EX II) manufactured by Nikkiso Co., Ltd. until it reached a measurable concentration, and ultrasonic dispersion was performed in the analyzer at 30 W for 60 seconds, after which the particle size distribution was measured over a measurement time of 10 seconds.

[0145] [Sphericity] The sphericity of the polyarylene sulfide copolymer particles or polyarylene sulfide particles was calculated from the major and minor axes of 30 randomly selected particles observed in a photograph taken with a Keyence digital microscope (VHX-7000) according to the following formula: The major axis is the diameter at which the distance between two parallel lines is maximum when an image of the particle is sandwiched between two parallel lines, and the minor axis is the diameter at which the distance between two parallel lines is minimum when an image of the particle is sandwiched between two parallel lines in a direction perpendicular to the major axis.

[0146]

[0147] In the formula, S is the sphericity, n is the number of measurements, and a ｉ is the major axis of the i-th particle, b ｉ is the minor axis of the i-th particle. The number of measurements, n, is 30.

[0148] Reference Example 1 An autoclave equipped with a stirrer and a bottom plug valve was charged with 9.5 kg (81.9 mol) of 48.4% sodium hydrosulfide, 3.84 kg (93.1 mol) of 97% sodium hydroxide, 13.4 kg (135 mol) of N-methyl-2-pyrrolidone (NMP), and 9.82 kg of ion-exchanged water, and gradually heated to 225°C over approximately 3 hours at normal pressure while passing nitrogen through. When the temperature reached 225°C, heating was stopped and cooling was initiated.

[0149] Thereafter, the reaction vessel was cooled to 200°C, and 12.6 kg (85.9 mol) of p-dichlorobenzene (p-DCB), 1.07 kg (8.23 mol) of 4-aminothiophenol (4-ATP), and 19.8 kg (200 mol) of NMP were added thereto. The reaction vessel was then sealed under nitrogen gas, and the temperature was raised to 260°C at a rate of 0.6°C / min with stirring, and the reaction was carried out at 260°C for 120 minutes.

[0150] Immediately after the reaction was completed, the bottom plug valve of the autoclave was opened, and the contents were flushed into an apparatus equipped with a stirrer, and the contents were dried and solidified for 1.5 hours in the apparatus equipped with a stirrer at 230°C, and a solid containing PPS and salts was recovered.

[0151] The obtained solid and ion-exchanged water were placed in an autoclave equipped with a stirrer, and a washing step was carried out at 75°C for 15 minutes, followed by filtration through a filter. This procedure was repeated three times to obtain a cake. The obtained cake and 30 liters of ion-exchanged water were placed in an autoclave equipped with a stirrer, and the inside of the autoclave was replaced with nitrogen, and then the temperature was raised to 195°C. Thereafter, the autoclave was cooled, and the contents were filtered through a filter to obtain a cake. The obtained cake was dried at 120°C under a nitrogen stream.

[0152] 3 kg of the dried cake and 30 kg of N-methyl-2-pyrrolidone (NMP) were placed in a container equipped with a stirrer, stirred for 30 minutes, and then filtered to obtain a cake. The resulting cake was washed with 30 L of ion-exchanged water for 15 minutes and filtered three times, and then dried at 120°C for 4 hours under a nitrogen stream to obtain dried PPS. The resulting PPS had an amino group content of 510 μmol / g and a number-average molecular weight of 3,200.

[0153] [Reference Example 2] The PPS obtained in Reference Example 1 and pyromellitic anhydride were dry-blended so that the molar ratio of the amount of acid anhydride groups in pyromellitic anhydride to the amount of amino groups in PPS was 1.200, and the mixture was melt-kneaded using a TEX30α type twin-screw extruder (L / D: 45, kneading zones: 3) manufactured by The Japan Steel Works, Ltd., equipped with a vacuum vent, at a cylinder temperature of 300°C and a screw rotation speed of 200 rpm to cause reaction, thereby obtaining a PPS copolymer.

[0154] FT-IR spectrum confirmed that the obtained PPS copolymer contained phenylene sulfide units as structural units and that imide groups had been introduced. DSC measurement revealed that the PPS copolymer had a glass transition temperature of 114°C, a crystallization temperature of 171°C, and a melting point of 263°C. GPC measurement revealed that the Mw was 46,700. The melt complex viscosity was 240 Pa s. The PPS copolymer was in pellet form. The results are summarized in Table 1.

[0155] Reference Example 3 A PPS copolymer was obtained in the same manner as in Reference Example 2, except that the pyromellitic anhydride and PPS were dry-blended so that the molar ratio of the amount of acid anhydride contained in the pyromellitic anhydride to the amount of amino groups contained in the PPS was 1.213.

[0156] FT-IR spectrum confirmed that the obtained PPS copolymer contained phenylene sulfide units as structural units and that imide groups had been introduced. DSC measurement results indicated that the PPS copolymer had a glass transition temperature of 114°C, a crystallization temperature of 205°C, and a melting point of 262°C. GPC measurement results indicated that the Mw was 48,600. The melt complex viscosity measurement result was 176 Pa s. The PPS copolymer was in the form of pellets. The results are summarized in Table 1.

[0157] Example 1 4.0 g of the PPS copolymer obtained in Reference Example 2 and 6.0 g of PEG20000 (manufactured by Tokyo Chemical Industry Co., Ltd.) (melt complex viscosity: 0.80 Pa s) were added to a small melt kneader equipped with a circulation mechanism, Haake MiniLab II, and melt-kneaded for 3 minutes at a cylinder temperature of 300 ° C and a screw rotation speed of 200 rpm, and then discharged into a tray filled with ion-exchanged water. At this time, the melt complex viscosity ratio (ηa / ηb) of the melt viscosity (ηa) of the PPS copolymer to the melt viscosity (ηb) of the PEG20000 was 301. Suction filtration was performed using filter paper as a filter medium, and the resulting cake was reslurried with ion-exchanged water and suction-filtered using filter paper. This washing process was repeated three times to obtain polyarylene sulfide copolymer particles. The glass transition temperature of the polyarylene sulfide copolymer particles was 110 ° C, and the melting point was 259 ° C. The Mw was 53,000, and the Mw retention of the PPS copolymer particles relative to the Mw of the PPS copolymer of Reference Example 2 was 113%. The polyarylene sulfide copolymer particles had a D50 of 80.6 μm and a D90 / D10 of 1.7. The sphericity was 93. The results are summarized in Table 1.

[0158] Example 2 PPS copolymer particles were obtained in the same manner as in Example 1, except that PEG500000 (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) (melt complex viscosity: 7.9 Pa s) was used instead of PEG20000. The melt complex viscosity ratio (ηa / ηb) of the melt viscosity (ηa) of the PPS copolymer to the melt viscosity (ηb) of PEG500000 was 30. The polyarylene sulfide copolymer particles had a glass transition point of 110°C and a melting point of 261°C. The Mw was 51,800, and the Mw retention of the PPS copolymer particles relative to the Mw of the PPS copolymer of Reference Example 2 was 111%. The polyarylene sulfide copolymer particles had a D50 of 5.9 μm and a D90 / D10 of 2.1. The sphericity was 93. The results are summarized in Table 1.

[0159] Example 3 PPS copolymer particles were obtained in the same manner as in Example 2, except that the PPS copolymer of Reference Example 3 was used instead of the PPS copolymer of Reference Example 2. At this time, the melt complex viscosity ratio (ηa / ηb) of the melt viscosity (ηa) of the PPS copolymer to the melt viscosity (ηb) of PEG 500000 was 22. The polyarylene sulfide copolymer particles had a glass transition point of 110°C and a melting point of 261°C. The Mw was 46,200, and the Mw retention of the PPS copolymer particles relative to the Mw of the PPS copolymer of Reference Example 3 was 95%. The polyarylene sulfide copolymer particles had a D50 of 4.4 μm and a D90 / D10 of 2.0. The sphericity was 89. The results are summarized in Table 1.

[0160] Comparative Example 1: 1.5 g of the PPS copolymer obtained in Reference Example 2 was freeze-pulverized in liquid nitrogen for 23 minutes. The polyarylene sulfide copolymer particles had a D50 of 198 μm and a D90 / D10 ratio of 12.7. The sphericity was 64%. The results are summarized in Table 2.

[0161] Comparative Example 2: A 20 mL pressure vessel was charged with 0.3 g of the PPS copolymer obtained in Reference Example 2 and 4.5 g of NMP containing 1000 ppm water. The vessel was then purged with nitrogen and sealed. After heating at 250°C for 20 minutes while stirring at 240 rpm, the vessel was allowed to cool. After cooling to approximately room temperature over approximately 30 minutes while maintaining stirring, the mixture was removed from the pressure vessel, 20 mL of water was added, and the mixture was stirred and filtered. After repeated stirring and filtration in water to remove the solvent, the mixture was vacuum dried at 100°C to obtain polyarylene sulfide copolymer particles. The polyarylene sulfide copolymer particles had a glass transition temperature of 110°C, a crystallization temperature of 214°C, and a melting point of 261°C. The Mw was 25,300, and the Mw retention of the PPS copolymer particles relative to the Mw of the PPS copolymer of Reference Example 2 was 37%. The polyarylene sulfide copolymer particles in the methanol dispersion had a D50 of 15.9 μm, a D90 / D10 ratio of 5.5, and a sphericity of 76%. The results are summarized in Table 2.

[0162] Reference Example 4 A 70-liter autoclave equipped with a stirrer was charged with 8.27 kg (70.00 mol) of 47.5% sodium hydrosulfide, 2.96 kg (70.97 mol) of 96% sodium hydroxide, 11.43 kg (115.50 mol) of N-methyl-2-pyrrolidone (NMP), 2.58 kg (31.50 mol) of sodium acetate, and 10.5 kg of ion-exchanged water, and the mixture was gradually heated to 245°C over approximately 3 hours at atmospheric pressure while passing nitrogen through. After distilling off 14.78 kg of water and 0.28 kg of NMP, the reaction vessel was cooled to 160°C.

[0163] Next, 10.24 kg (69.63 mol) of p-dichlorobenzene and 9.01 kg (91.00 mol) of NMP were added, and the reaction vessel was sealed under nitrogen gas. The mixture was heated to 238°C at a rate of 0.6°C / min with stirring. After 95 minutes of reaction at 238°C, the mixture was heated to 270°C at a rate of 0.8°C / min. After 100 minutes of reaction at 270°C, the mixture was cooled to 250°C at a rate of 1.3°C / min while injecting 1.26 kg (70 mol) of water over 15 minutes. The mixture was then cooled to 200°C at a rate of 1.0°C / min and then rapidly cooled to near room temperature.

[0164] The contents were removed from the reaction vessel and diluted with 26.30 kg of NMP. The solvent and solids were filtered through an 80-mesh sieve. The resulting particles were washed with 31.90 kg of NMP and then filtered. The resulting particles were washed several times with 56.00 kg of ion-exchanged water, filtered, and then washed with 70.00 kg of 0.05 wt.% acetic acid aqueous solution and filtered. After further washing with 70.00 kg of ion-exchanged water and filtering, the resulting hydrous PPS particles were dried with hot air at 80°C and then dried under reduced pressure at 120°C. The PPS particles had a glass transition temperature of 94°C, a crystallization temperature of 219°C, and a melting point of 278°C. The Mw was 75,100. The results are summarized in Table 2.

[0165] Comparative Example 3 PPS particles were obtained under the same conditions as in Comparative Example 2, except that the PPS obtained in Reference Example 4 was used instead of the PPS copolymer obtained in Reference Example 2. The PPS particles had a glass transition temperature of 94°C, a crystallization temperature of 220°C, and a melting point of 278°C. The Mw was 73,300, and the Mw retention of the PPS particles relative to the Mw of the PPS in Reference Example 3 was 98%. The PPS particles had a D50 of 57.4 μm and a D90 / D10 of 2.6. The sphericity was 73%. The results are summarized in Table 2.

[0166] Reference Example 5 Melt kneading was carried out in the same manner as in Example 1, except that polyvinylpyrrolidone (K-30) (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) was used instead of PEG20000. However, the resulting mixture did not dissolve in ion-exchanged water, and no particles were obtained. At this time, the melt complex viscosity ratio (ηa / ηb) was 0.06. The results are summarized in Table 2.

[0167] Reference Example 6 Melt-kneading was carried out in the same manner as in Example 1, except that polyvinyl alcohol Mowiflex C-17 (manufactured by Kuraray Co., Ltd.) was used instead of PEG20000. However, the process was interrupted due to the generation of a large amount of decomposition gas, and no particles were obtained. At this time, the melt complex viscosity ratio (ηa / ηb) was 0.006. The results are summarized in Table 2.

[0168] Comparative Example 4 PPS particles were obtained under the same conditions as in Example 1, except that the PPS obtained in Reference Example 4 was used instead of the PPS copolymer obtained in Reference Example 2. The melt complex viscosity ratio (ηa / ηb) of the PPS (ηa) to the PEG 20000 (ηb) was 297. The PPS particles had a glass transition temperature of 94°C, a crystallization temperature of 220°C, and a melting point of 278°C. The Mw was 66,000, and the Mw retention of the PPS particles relative to the Mw of the PPS in Reference Example 4 was 88%. The PPS particles had a D50 of 303 μm and a D90 / D10 ratio of 6.4. The sphericity was 86%. The results are summarized in Table 2.

[0169]

[0170]

[0171] From Examples 1 to 3, it was found that the method of the present invention can provide polyarylene sulfide copolymer particles having high heat resistance and high sphericity.

[0172] As shown in Comparative Example 1, when the pellet-shaped PPS copolymer was freeze-pulverized, the sphericity was smaller than that of the PPS copolymer particles obtained in Examples 1 to 3. In addition, both the D50 particle size and the D90 / D10 ratio were larger.

[0173] It was found from Comparative Examples 2 and 3 that the particles obtained by dissolving and precipitating a PPS copolymer or PPS in a solvent had low sphericity, and in the case of PPS, the Tg was low and the heat resistance was poor.

Claims

1. Polyarylene sulfide copolymer particles having a median diameter D50 of 1 μm or more and 1,000 μm or less, a glass transition point of 95°C or more and 190°C or less when measured using a differential scanning calorimeter, and a sphericity of 80 or more and 100 or less.

2. The polyarylene sulfide copolymer particles according to claim 1, wherein the median diameter D50 is 1 μm or more and 150 μm or less.

3. The polyarylene sulfide copolymer particles according to claim 1, which have a weight average molecular weight Mw of 30,000 or more.

4. Polyarylene sulfide copolymer particles according to claim 1, wherein the polyarylene sulfide copolymer constituting the polyarylene sulfide copolymer particles contains at least one bonding group selected from a sulfonyl group, a sulfinyl group, an ester group, an amide group, an imide group, an ether group, a urea group, a urethane group, and a siloxane group.

5. A method for producing polyarylene sulfide copolymer particles, comprising step 1 of melt-kneading a polyarylene sulfide copolymer having a glass transition point of 95°C or higher and 190°C or lower when measured using a differential scanning calorimeter with a water-soluble thermoplastic resin, and step 2 of removing the water-soluble thermoplastic resin by washing with water or an alcohol.

6. A method for producing polyarylene sulfide copolymer particles according to claim 5, wherein the viscosity ratio ηa / ηb of the melt viscosity (ηa) of the polyarylene sulfide copolymer to the melt viscosity (ηb) of the water-soluble thermoplastic resin is 0.1 or more and 1000 or less.

7. A dispersion in which the polyarylene sulfide copolymer particles according to claim 1 are dispersed in a liquid.

8. A three-dimensional object molded from the polyarylene sulfide copolymer particles according to claim 1.

9. A method for producing a reinforced fiber composite substrate, comprising the steps of dispersing the polyarylene sulfide copolymer particles according to claim 1 in reinforcing fibers, and melting the polyarylene sulfide copolymer particles and impregnating the reinforcing fibers with the melted polyarylene sulfide copolymer particles.

10. A reinforcing fiber composite substrate produced by the method for producing a reinforcing fiber composite substrate according to claim 9.

11. A molded article obtained by molding the reinforcing fiber composite substrate according to claim 10.

12. The molded article according to claim 11, which is an aircraft structural component.

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