Polyarylene sulfide

Abstract

Provided is a polyarylene sulfide having excellent moisture resistance and high melt viscosity.　For PAS having a high melt viscosity in a specific range, the heat of fusion is 36.0 J / g or more. When the polyarylene sulfide is a polymer derived from dichlorobenzene, trichlorobenzene, and a sulfur source, the melt viscosity is taken to be MV, and the chlorine content (ppm) is taken to be ACl, MV and ACl preferably satisfy formula (1), formula (2), and formula (3): ACl≥-1001.5×MV / 105+8850 (1), ACl≤-911.85×MV / 105+9400 (2), MV≥1.0×105 (3).

Description

Polyarylene sulfide

[0001] The present invention relates to polyarylene sulfides.

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

[0003] When the PAS resin is molded into a molded product, burrs often occur. To prevent the occurrence of such burrs, a PAS having a high melt viscosity is used as a burr suppressant (see Patent Document 1). In order to function as a burr suppressant, a measurement temperature of 330°C and a shear rate of 2 sec －１ The melt viscosity measured under the conditions is 1.0 × 10 ５ Pa・s~5.0×10 ５ The range is suitable.

[0004] On the other hand, as such a high melt viscosity PAS, there has been proposed a PAS production method including: (1) a charging step of preparing a charging mixture containing an organic polar solvent, a sulfur source, and a dihaloaromatic compound; (2) a first-stage polymerization step of heating the charging mixture to initiate a polymerization reaction and produce a prepolymer; (3) a phase separation step of adding water as a phase separation agent to the reaction mixture in the reaction system to form a phase-separated state; and (4) a second-stage polymerization step of continuing the polymerization reaction after the phase separation step, in which the conversion rate of the dihaloaromatic compound in the first-stage polymerization step is more than 80 mass% but not more than 93 mass%, and the polyhaloaromatic compound is added to the reaction mixture after the weight average molecular weight of the prepolymer has reached 10,000 or more (see Patent Document 2).

[0005] Furthermore, various devices in which molded articles containing PAS as a main component are used are becoming smaller and more sophisticated every day. As a result, molded articles containing PAS as a main component are increasingly being exposed to harsher environments. For these reasons, PAS is desired to have higher moisture resistance than ever before.

[0006] Patent No. 5222474 Patent No. 7394987

[0007] As described above, PAS has excellent heat resistance, chemical resistance, etc. Therefore, PAS is sometimes used in harsh environments such as high-temperature and high-humidity environments. However, the PAS produced by the method described in Patent Document 2 has a problem of low moisture resistance.

[0008] The present invention has been made in view of the above problems, and an object of the present invention is to provide a polyarylene sulfide that has excellent moisture resistance and a high melt viscosity.

[0009] The present inventors have found that the above object can be achieved by setting the heat of fusion of a PAS exhibiting a high melt viscosity within a specific range to 36.0 J / g or more, and have thus completed the present invention.

[0010] The PAS according to the present invention exhibits a heat of fusion of 36.0 g / J or more, and is measured at a temperature of 330°C and a shear rate of 2 sec. －１ The melt viscosity measured under the conditions is 1.0 × 10 ５ It is a polyarylene sulfide having a viscosity of Pa·s or more.

[0011] The PAS according to the present invention is a polymer derived from dichlorobenzene, trichlorobenzene, and a sulfur source, and has a melt viscosity of MV and a chlorine content (ppm) of A. Ｃｌ In this case, MV and A Ｃｌ is represented by the following formula (1), the following formula (2), and the following formula (3): A Ｃｌ ≧-1001.5×MV / 10 ５ +8850 (1) A Ｃｌ ≦-911.85×MV / 10 ５ +9400 (2) MV≧1.0×10 ５ It is preferable that (3) is satisfied.

[0012] The PAS that satisfies the above formulas (1) to (3) further satisfies the following formula (4): 4000≦A Ｃｌ It is preferable that the following condition is satisfied: ≦9000.

[0013] According to the present invention, it is possible to provide a polyarylene sulfide that has excellent moisture resistance and a high melt viscosity.

[0014] FIG. 1 shows a graph in which data on melt viscosity and chlorine content for Example 1, Examples 3 to 8, Comparative Example 1, and Comparative Examples 3 to 9 are plotted on a coordinate plane having a horizontal axis representing melt viscosity and a vertical axis representing chlorine content.

[0015] One embodiment of the PAS according to the present invention will be described below. The PAS in this embodiment exhibits a heat of fusion of 36.0 g / J or more. －１ The melt viscosity measured under the conditions is 1.0 × 10 ５ The PAS has a high melt viscosity and exhibits excellent moisture resistance.

[0016] The above PAS will be explained below.

[0017] <Method for producing PAS> The method for producing the PAS is not particularly limited. A preferred method for producing the PAS includes: (1) a charging step of preparing a charging mixture containing an organic polar solvent, a sulfur source, and a dihaloaromatic compound; (2) a first-stage polymerization step of heating the charging mixture to initiate a polymerization reaction and produce a prepolymer; (3) a phase separation step of adding a phase separation agent to the reaction mixture in the reaction system to form a phase-separated state; and (4) a second-stage polymerization step of continuing the polymerization reaction after the phase separation step. In the first-stage polymerization step, when the conversion rate of the dihaloaromatic compound is 95% by mass or more, after the weight-average molecular weight of the prepolymer has reached 13,000 or more and 27,000 or less, an aromatic compound having three or more halogen atoms bonded to an aromatic ring is added to the reaction mixture in the reaction system, and 2.30 mol or more and 5.00 mol or less of the phase separation agent is added to the reaction mixture in the reaction system per 1 mol of the available sulfur source.

[0018] That is, the above method includes, as essential steps, a charging step, a polymerization step, a phase separation step, and a post-polymerization step. The above method may also include, as desired, a dehydration step, a cooling step, a post-treatment step, etc. Hereinafter, each material used in the production of PAS will be described in detail, and each step will be described in detail.

[0019] In the specification and claims of this application, a "dihaloaromatic compound" refers to a halogenated aromatic compound having two or more halogen atoms directly bonded to an aromatic ring. In the specification and claims of this application, a "polyhaloaromatic compound" refers to a halogenated aromatic compound having three or more halogen atoms directly bonded to an aromatic ring.

[0020] (Organic polar solvent, sulfur source, and dihaloaromatic compound) The organic polar solvent, sulfur source, and dihaloaromatic compound are not particularly limited, and those typically used in the production of PAS can be used. Each of the organic polar solvent, sulfur source, and dihaloaromatic compound may be used alone, or two or more types may be mixed and used as long as the combination allows the production of PAS having the desired chemical structure.

[0021] Examples of organic polar solvents include organic amide solvents such as N,N-dimethylformamide, N,N-dimethylacetamide, N-methyl-ε-caprolactam, N-methyl-2-pyrrolidone (hereinafter also referred to as "NMP"), N-cyclohexyl-2-pyrrolidone, 1,3-dialkyl-2-imidazolidinone, tetramethylurea, and hexamethylphosphoric triamide, as well as aprotic organic polar solvents composed of organic sulfur compounds such as dimethyl sulfoxide and diphenyl sulfone. Among these, in terms of availability, handleability, etc., organic amide solvents are preferred, N-alkylpyrrolidone compounds are more preferred, and NMP is particularly preferred.

[0022] From the viewpoint of the efficiency of the polymerization reaction, the amount of the organic polar solvent used is preferably 1 to 30 mol, more preferably 3 to 15 mol, per mol of the sulfur source.

[0023] Examples of sulfur sources include alkali metal sulfides, alkali metal hydrosulfides, and hydrogen sulfide, with alkali metal hydrosulfides being preferred. The sulfur source may be used as a hydrate or an aqueous solution. From the viewpoint of handling such as measurement and transportability, the sulfur source is preferably in the form of an aqueous solution. Examples of alkali metal sulfides include lithium sulfide, sodium sulfide, potassium sulfide, rubidium sulfide, and cesium sulfide. Examples of alkali metal hydrosulfides include lithium hydrosulfide, sodium hydrosulfide, potassium hydrosulfide, rubidium hydrosulfide, and cesium hydrosulfide.

[0024] Examples of dihaloaromatic compounds include o-dihalobenzene, m-dihalobenzene, p-dihalobenzene, dihalotoluene, dihalonaphthalene, methoxy-dihalobenzene, dihalobiphenyl, dihalobenzoic acid, dihalodiphenyl ether, dihalodiphenyl sulfone, dihalodiphenyl sulfoxide, and dihalodiphenyl ketone. Two or more dihaloaromatic compounds may be used in combination. Halogen atoms refer to fluorine, chlorine, bromine, and iodine atoms, and the two or more halogen atoms in a dihaloaromatic compound may be the same or different. Among these, p-dihalobenzene is preferred in terms of availability, reactivity, and the like, and p-dichlorobenzene (hereinafter also referred to as "pDCB") is more preferred.

[0025] The amount of dihaloaromatic compound used is preferably 0.90 to 1.50 mol, more preferably 0.92 to 1.10 mol, per mol of the sulfur source charged. When the amount used is within the above range, decomposition reactions are less likely to occur, stable polymerization reactions are easily carried out, and the degree of polymerization per PAS oligomer molecule is increased. As a result, a high-molecular-weight polymer is easily produced, and a PAS with a high melt viscosity can be obtained. Furthermore, from the viewpoint of reducing the chlorine content of the PAS described below, the amount used is more preferably 0.99 to 1.10 mol, and particularly preferably 1.04 to 1.08 mol.

[0026] (Dehydration Step) The dehydration step is a step of discharging at least a portion of a distillate containing water from a system containing a mixture containing an organic polar solvent and a sulfur source to the outside of the system before the charging step. The dehydration step can be carried out according to a conventional method. The mixture subjected to the dehydration step may contain an alkali metal hydroxide, if necessary. It is preferable to reduce the amount of water in the polymerization reaction system by carrying out a dehydration treatment before polymerization so that the amount of water in the system containing the mixture does not inhibit the polymerization reaction.

[0027] In the dehydration step, dehydration is preferably performed by heating under an inert gas atmosphere. The moisture to be removed in the dehydration step includes water contained in each raw material mixed in the dehydration step, water produced as a by-product by reaction between each raw material, etc.

[0028] The heating temperature and heating time in the dehydration step are not particularly limited and can be selected appropriately. For example, the heating temperature may be 100° C. or higher and 300° C. or lower. The heating time may be 15 minutes to 24 hours.

[0029] In the dehydration step, dehydration is carried out until the water content falls within a predetermined range. That is, in the dehydration step, dehydration is desirably carried out until the water content in the charge mixture (described below) is preferably 0.5 to 2.4 mol per 1.0 mol of the sulfur source (hereinafter also referred to as "charged sulfur source" or "available sulfur source"). If the water content becomes too low in the dehydration step, water may be added in the charge step prior to the primary polymerization step to adjust the water content to the desired level.

[0030] (Charge Step) The charge step is a step of preparing a mixture containing an organic polar solvent, a sulfur source, and a dihaloaromatic compound. The mixture charged in the charge step is also referred to as a "charge mixture."

[0031] When a dehydration step is performed, the amount of the sulfur source in the charged mixture (hereinafter also referred to as the "amount of charged sulfur source" or the "amount of available sulfur source") can be calculated by subtracting the molar amount of hydrogen sulfide vaporized in the dehydration step from the molar amount of the sulfur source charged as a raw material.

[0032] When a dehydration step is performed, an alkali metal hydroxide and water can be added as needed to the mixture remaining in the system after the dehydration step in the charging step. In particular, the alkali metal hydroxide can be added taking into consideration the amount of hydrogen sulfide and the amount of alkali metal hydroxide generated during dehydration. As the alkali metal hydroxide, one typically used in the production of PAS can be used. The alkali metal hydroxide may be used alone, or two or more types may be mixed and used as long as the combination allows the production of PAS. Examples of alkali metal hydroxides include lithium hydroxide and sodium hydroxide. The number of moles of the alkali metal hydroxide is calculated based on the number of moles of the alkali metal hydroxide added as needed in the charging step, and, when a dehydration step is performed, the number of moles of the alkali metal hydroxide added as needed in the dehydration step, and the number of moles of the alkali metal hydroxide generated in the dehydration step due to the generation of hydrogen sulfide. When the sulfur source contains an alkali metal sulfide, the number of moles of alkali metal hydroxide per mole of the sulfur source (charged sulfur source) is calculated including the number of moles of alkali metal sulfide. When hydrogen sulfide is used as the sulfur source, the number of moles of alkali metal hydroxide per mole of the sulfur source (charged sulfur source) is calculated including the number of moles of alkali metal sulfide produced. However, the number of moles of alkali metal hydroxide added for other purposes, for example, when an organic carboxylic acid metal salt is used as a phase separation agent in combination with an organic carboxylic acid and an alkali metal hydroxide, the number of moles of alkali metal hydroxide consumed in reactions such as neutralization, is not included in the number of moles of alkali metal hydroxide per mole of the sulfur source (charged sulfur source). Furthermore, when at least one acid selected from the group consisting of inorganic acids and organic acids is used for some reason, the number of moles of alkali metal hydroxide required to neutralize the at least one acid is not included in the number of moles of alkali metal hydroxide per mole of the sulfur source (charged sulfur source).

[0033] In the charge mixture, the amounts of the organic polar solvent and the dihaloaromatic compound used are set, for example, within the ranges described above for the organic polar solvent and the dihaloaromatic compound per mole of the charged amount of the sulfur source. The amount of the organic polar solvent in the charge mixture used in the first-stage polymerization step is not particularly limited. The amount of the organic polar solvent is preferably 500 g or less per mole of the sulfur source. The lower limit of the amount of the organic polar solvent in the charge mixture is not particularly limited, as long as the charge mixture can be well flowed in the first-stage polymerization step. The lower limit of the amount of the organic polar solvent in the charge mixture is preferably 200 g or more per mole of the sulfur source.

[0034] (Pre-stage polymerization step, phase separation agent addition step, and post-stage polymerization step) The pre-stage polymerization step is a step in which a charged mixture is heated to initiate a polymerization reaction and produce a prepolymer. In the pre-stage polymerization step, a sulfur source and a dihaloaromatic compound are polymerized in an organic polar solvent to produce a prepolymer of unbranched PAS. The mixture heated in the pre-stage polymerization step and the post-stage polymerization step, the mixture to which a phase separation agent is added in the phase separation agent addition step, and the mixture phase-separated in the phase separation agent addition step are collectively referred to as the "reaction mixture."

[0035] To obtain a high-molecular-weight PAS, the polymerization reaction is carried out in two or more stages. Specifically, the polymerization reaction is carried out in the presence of a phase separation agent in a second polymerization stage. The phase separation agent is added to the reaction mixture in a phase separation agent addition step between the first polymerization stage and the second polymerization stage.

[0036] In the first-stage polymerization step, when the conversion rate of the dihaloaromatic compound is 95% by mass or more, after the weight average molecular weight of the prepolymer reaches 13,000 to 27,000, a polyhaloaromatic compound is added to the reaction mixture in the reaction system. Subsequently, the phase separation agent is added in an amount of 2.4 to 3.5 moles per mole of the available sulfur source, and the second-stage polymerization is carried out. By adding the polyhaloaromatic compound in this manner, a PAS having a heat of fusion of 36.0 J / g or more and a high melt viscosity can be produced. The conversion rate of the dihaloaromatic compound can be calculated by determining the amount of dihaloaromatic compound remaining in the reaction mixture by gas chromatography, and based on the remaining amount, the amount of dihaloaromatic compound charged, and the amount of sulfur source charged. In this specification, the weight average molecular weight refers to the weight average molecular weight in terms of polystyrene measured by gel permeation chromatography.

[0037] In addition, after setting the conditions for the first-stage polymerization step in advance, the reaction in the first-stage polymerization step is carried out, and then the reaction mixture containing an unbranched PAS prepolymer is obtained by cooling to around room temperature without adding TCB. The cooling rate is preferably 0.4 ° C. / min or more. This reaction mixture is used as a sample, and the dihaloaromatic compound conversion rate and the weight average molecular weight of PAS measured by the above-mentioned method can be used as the dihaloaromatic compound conversion rate and the weight average molecular weight of the prepolymer when the polyhaloaromatic compound is added. In this way, by knowing the dihaloaromatic compound conversion rate and the weight average molecular weight of the prepolymer in the first-stage polymerization step, the timing of adding the polyhaloaromatic compound can be determined in advance.

[0038] In the first-stage polymerization step, when the conversion rate of the dihaloaromatic compound is 95% by mass or more, the weight average molecular weight of the prepolymer reaches 13,000 to 27,000, and then the polyhaloaromatic compound is added to the reaction mixture in the reaction system. In order to obtain a PAS with a desired heat of fusion, the conversion rate of the dihaloaromatic compound when the polyhaloaromatic compound is added is 95% by mass or more. The upper limit of the conversion rate is, for example, preferably 99% by mass or less, and may be 98% by mass or less, or 97% by mass or less. The polyhaloaromatic compound can be added to the reaction mixture as a powder, melt, solution, or dispersion. When the polyhaloaromatic compound is added as a solution or dispersion, the above-mentioned organic polar solvents can be preferably used as the solvent or dispersion medium.

[0039] Thus, in the first-stage polymerization step, by adding a polyhaloaromatic compound to the reaction mixture in the reaction system when the conversion rate of the dihaloaromatic compound is 95% or more, a PAS with a high heat of fusion can be obtained. Increasing the conversion rate of the dihaloaromatic compound in the first-stage polymerization step increases the molecular weight of the prepolymer, thereby reducing the reactivity with the polyhaloaromatic compound. This is thought to be because the amount of prepolymer that reacts with all the halogen atoms of the polyhaloaromatic compound decreases. For example, when a polyhaloaromatic compound having three halogen atoms is added, a PAS obtained by reacting all three halogen atoms and a PAS obtained by reacting only two halogen atoms of the polyhaloaromatic compound are obtained, and the proportion of the latter PAS is higher than in the past, which is thought to increase the heat of fusion.

[0040] Examples of halogen atoms in polyhaloaromatic compounds include fluorine, chlorine, bromine, and iodine. The three or more halogen atoms in a polyhaloaromatic compound may be the same or different. The number of halogen atoms bonded to the aromatic ring in a polyhaloaromatic compound is not particularly limited as long as it is three or more, and is preferably an integer of 3 to 5, more preferably 3 or 4, and particularly preferably 3. One type of polyhaloaromatic compound may be used alone, or two or more types may be used in combination.

[0041] Specific preferred examples of the polyhaloaromatic compound added to the reaction mixture in the first-stage polymerization step include polyhaloaromatic compounds having three or more halogen substitutions, such as 1,2,3-trichlorobenzene, 1,2,4-trichlorobenzene, 1,3,5-trichlorobenzene, hexachlorobenzene, 1,2,3,4-tetrachlorobenzene, 1,2,4,5-tetrachlorobenzene, 1,3,5-trichloro-2,4,6-trimethylbenzene, 2,4,6-trichlorotoluene, 1,2,3-trichloronaphthalene, 1,2,4-trichloronaphthalene, 1,2,3,4-tetrachloronaphthalene, 2,2',4,4'-tetrachlorobiphenyl, 2,2',4,4'-tetrachlorobenzophenone, and 2,4,2'-trichlorobenzophenone.

[0042] From the viewpoints of reactivity with oligomers or prepolymers, the degree of polymerization (melt viscosity) of the resulting PAS, yield, etc., 1,2,4-trichlorobenzene is particularly preferred as the polyhalo aromatic compound. Hereinafter, 1,2,4-trichlorobenzene may be referred to as TCB.

[0043] The amount of polyhaloaromatic compound added in the first-stage polymerization step is preferably 0.005 to 0.200 mol, more preferably 0.005 to 0.150 mol, even more preferably 0.005 to 0.100 mol, still more preferably 0.010 to 0.100 mol, and particularly preferably 0.010 to 0.050 mol, per mol of the sulfur source. If the amount of polyhaloaromatic compound per mol of the sulfur source is too small, it may be difficult to obtain PAS in high yield. If the amount of polyhaloaromatic compound is too large, production costs may increase and the crosslinking reaction may proceed excessively, resulting in a smaller average particle size of the granular PAS and a reduced amount of PAS that can be recovered as a product.

[0044] In the first-stage polymerization step and the second-stage polymerization step, from the viewpoint of the efficiency of the polymerization reaction, etc., it is preferable to carry out the polymerization reaction under heating at a temperature of 170 to 300°C. The polymerization temperature in the first-stage polymerization step and the second-stage polymerization step is more preferably in the range of 180 to 290°C in order to suppress side reactions and decomposition reactions. In particular, in the first-stage polymerization step, from the viewpoint of the efficiency of the polymerization reaction, it is preferable to start the polymerization reaction under heating at a temperature of 170 to 270°C, to achieve a conversion rate of the dihaloaromatic compound of 95% by mass or more, and to produce a prepolymer having a weight-average molecular weight of 13,000 to 27,000. The polymerization temperature in the first-stage polymerization step is preferably selected from the range of 180 to 265°C in order to suppress side reactions and decomposition reactions.

[0045] In the second-stage polymerization step following the first-stage polymerization step, the degree of polymerization of the prepolymer is increased. In the second-stage polymerization step, the reaction system containing the prepolymer produced in the first-stage polymerization step described above is heated to continue the polymerization reaction in a phase-separated state. The polymerization temperature in the second-stage polymerization step may be any temperature that induces a phase-separated state and does not decompose the produced PAS or organic polar solvent. The polymerization temperature in the second-stage polymerization step is usually preferably higher than that in the first-stage polymerization step. The polymerization temperature in the second-stage polymerization step is preferably 240 to 290°C, more preferably 250 to 280°C, and even more preferably 255 to 275°C. If the polymerization temperature in the second-stage polymerization step is too low, the phase-separated state will not occur, making it difficult to obtain a PAS with a high degree of polymerization. If the polymerization temperature is too high, the produced PAS or organic polar solvent may decompose. The polymerization temperature is preferably maintained at a constant temperature. The polymerization temperature may be increased or decreased stepwise or continuously during the second-stage polymerization step as necessary.

[0046] Due to the presence of the phase separation agent, in the second-stage polymerization step, the polymerization reaction system (reaction mixture) undergoes phase separation into a polymer-rich phase (a phase having a high polymer concentration in the organic amide solvent) and a polymer-lean phase (a phase having a low polymer concentration in the organic amide solvent). Phase separation may be induced during the second-stage polymerization step by adjusting the timing of addition of the phase separation agent, adjusting the polymerization temperature, etc.

[0047] As the phase separation agent, a water-containing phase separation agent is used because it is easy to form a good phase separation state. In the phase separation agent addition step, a phase separation agent other than water may be used together with water. The phase separation agent other than water is not particularly limited. Examples of the phase separation agent other than water include at least one selected from the group consisting of organic carboxylic acid metal salts (e.g., alkali metal salts of aliphatic carboxylic acids such as sodium acetate, alkaline earth metal salts of aromatic carboxylic acids, etc.), organic sulfonic acid metal salts, alkali metal halides, alkaline earth metal halides, alkali metal phosphates, alcohols, and nonpolar solvents. The above salts used as phase separation agents may be added separately as the corresponding acid and base. When water and a phase separation agent other than water are used in combination, it is preferable to use a combination of water and an organic carboxylic acid metal salt, and more preferably a combination of water and sodium acetate. When water and an organic carboxylic acid metal salt are used in combination, the mass of water as the phase separation agent is preferably 10 to 50 times, more preferably 20 to 30 times, the mass of the organic carboxylic acid metal salt.

[0048] The amount of phase separation agent used varies depending on the type of compound used, but may be within the range of 0.01 to 20 moles per 1 kg of organic polar solvent. The amount of water added as a phase separation agent is determined taking into account the total amount of water contained in the reaction mixture. The total amount of water contained in the reaction mixture after the addition of the phase separation agent is preferably 2.30 to 5.00 moles per mole of available sulfur source, more preferably 2.30 to 3.50 moles. The amount of water in the reaction mixture is the amount of water contained in the raw materials and is calculated from the composition of the raw materials. When a dehydration step is performed, the amount of water in the reaction mixture is calculated based on the measured amount of water removed in the dehydration step and the composition of the raw materials. The technical significance of adding a phase separation agent after the first-stage polymerization and performing the second-stage polymerization is that by adding a phase separation agent after producing a prepolymer in the first-stage polymerization, a liquid-liquid phase separation state containing a phase with a high prepolymer concentration (polymer-rich phase) is created. Prepolymers with relatively high molecular weights and prepolymers in which the crosslinking reaction has progressed tend to exist in the polymer-rich phase. Furthermore, the greater the amount of phase separation agent added, the less prepolymer remains in the phase with a low prepolymer concentration (polymer-lean phase). By ensuring that the total amount of water in the reaction mixture is within the above range, prepolymers with a low degree of progress in the crosslinking reaction with the polyhaloaromatic compound can also be present in the polymer-rich phase. For example, when trichlorobenzene is used as the polyhaloaromatic compound, a prepolymer with a low degree of progress in the crosslinking reaction with the polyhaloaromatic compound is a prepolymer that has reacted with two of the three chlorine atoms of trichlorobenzene. The volume of the prepolymer in the rich phase is smaller than the volume of the solvated prepolymer in the dilute phase. Therefore, the molecular chain of the prepolymer contained in the rich phase is considered to be in a relatively folded state. As a result, the reaction between the molecular chain ends of the prepolymer proceeds smoothly, while the crosslinking reaction at the Cl terminal groups derived from TCB located in the main chain is difficult to proceed. As a result, the PAS according to the present invention is considered to be obtained.

[0049] In the second-stage polymerization step, the amount of alkali metal hydroxide is preferably 1.00 to 1.10 mol, more preferably 1.01 to 1.08 mol, and even more preferably 1.02 to 1.07 mol per mol of the sulfur source. When the amount of alkali metal hydroxide is within the above range, the molecular weight of the resulting PAS is more likely to increase, making it easier to obtain a PAS with a higher molecular weight. In the second-stage polymerization step, it is preferable to add alkali metal hydroxide to the reaction mixture so that the final amount of alkali metal hydroxide falls within the above range, based on the amount of alkali metal hydroxide present in the reaction mixture after the first-stage polymerization step.

[0050] The polymerization reactions in the first-stage polymerization step and the second-stage polymerization step may be carried out batchwise or continuously. For example, the polymerization reaction can be carried out continuously by simultaneously carrying out at least the supply of an organic polar solvent, a sulfur source, and a dihaloaromatic compound, the production of PAS by the reaction of the sulfur source with the dihaloaromatic compound in the organic polar solvent, and the recovery of the reaction mixture containing PAS.

[0051] (Post-treatment step and recovery step) The PAS produced by the method described above is usually recovered through a post-treatment step and a recovery step. The post-treatment step and the recovery step can be carried out by a conventional method. For example, a slurry containing a granular polymer product can be obtained by cooling the reaction mixture after the second-stage polymerization step. The cooled product slurry can be filtered as is or after diluting with water or the like, and then washed and filtered repeatedly, followed by drying, to recover the PAS.

[0052] By producing granular PAS by the above method, the granular PAS can be separated from the reaction solution, for example, by sieving using a screen. In this way, the PAS can be easily separated from by-products, oligomers, etc. The granular PAS may be sieved while the product slurry is still in a high temperature state. Specifically, the product that does not pass through a 100 mesh (opening diameter 150 μm) screen (sometimes referred to as "100 mesh on") can be recovered as a granular PAS product. PAS that passes through a 100 mesh screen is difficult to handle and is often not recovered as a product.

[0053] The granular PAS recovered from the product slurry as described above is preferably washed with an organic solvent such as the aforementioned organic polar solvent, ketones (e.g., acetone), or alcohols (e.g., methanol). The granular PAS may also be washed with high-temperature water. The granular PAS can also be treated with an acid or a salt such as ammonium chloride.

[0054] According to the above method, the ratio of the mass of granular PAS that does not pass through a 100-mesh screen to the mass of all recovered PAS can be 86% by mass or more, preferably 88% by mass or more. The upper limit of the ratio of the mass of granular PAS that does not pass through a 100-mesh screen to the mass of all recovered PAS is not particularly limited, but may be, for example, 95% by mass or less, or may be 92% by mass or less, or may be 90% by mass or less.

[0055] As described above, according to the method described above, granular PAS having a relatively large particle size is recovered. The granular PAS having a large particle size recovered by the method described above may be pulverized to match the particle size of granular PAS obtained by conventional methods. Whether the granular PAS has been pulverized can be confirmed by observing the PAS particles under a microscope. By observing the pulverized PAS particles under a microscope, it is possible to confirm the characteristic appearance caused by pulverization, such as smooth surfaces resulting from particle cracking.

[0056] In the method for producing a PAS in this embodiment, the PAS is not particularly limited, but is preferably PPS.

[0057] <Method for measuring weight-average molecular weight> In the specification of this application, the weight-average molecular weight of PAS is a value determined using size exclusion chromatography. In the measurement by size exclusion chromatography, 1-chloronaphthalene is used as the solvent, and a TSKgel GMIHR-H(S)HT2 column (inner diameter x length: 7.8 mm x 30 cm) is used. The weight-average molecular weight is determined from a calibration curve using polystyrene as the standard substance.

[0058] <Method for measuring heat of fusion> (Heat of fusion of PAS) In various devices in which molded articles containing PAS as a main component are used, miniaturization and performance improvement are progressing, and the molded articles are increasingly being exposed to harsher environments. If the heat of fusion of PAS is low, the moisture resistance of the molded body may decrease, and the performance of the molded article may be impaired. In contrast, PAS showing a heat of fusion in the range of 36.0 J / g or more is preferred as a moisture-resistant PAS. The heat of fusion of PAS is more preferably 36.3 J / g or more, even more preferably 36.5 J / g or more, and particularly preferably 36.8 J / g or more. The upper limit of the heat of fusion is not particularly limited, but 50.0 J / g or less is preferred. (Measurement of heat of fusion by differential scanning calorimeter) In the specification of the present application, the heat of fusion of PAS is measured using a differential scanning calorimeter (DSC) under the following conditions, and is a value measured based on the melting peak observed during the second (second cycle) temperature increase from 50°C to 340°C (5) below). In the DSC measurement, a 100-mesh dried polymer is used as the measurement sample. The amount of sample is in the range of 8 mg to 12 mg. (Measurement conditions) Temperature profile: 1) 50°C 2) Heat up to 340°C at a rate of 10°C / min 3) Hold at 340°C for 1 minute 4) Cool down to 50°C at a rate of 10°C / min 5) Heat up to 340°C at a rate of 10°C / min Atmosphere: N ２ atmosphere

[0059] <Method for measuring melt viscosity> (Melt viscosity of PAS) It is known that PAS is molded by injection molding. However, if the melt viscosity of PAS is low during injection molding, flash may occur on the molded product, which may impair the performance and appearance of the molded product. －１ The melt viscosity measured under the conditions of ５ The PAS having a melt viscosity of 1.0×10 Pa·s or more is preferably used as a burr suppressant added to the PAS. ５ Pa・s or more 5.0×10 ５ Pa s or less is more preferable, and 1.0 × 10 ５ Pa・s or more 3.0×10 ５It is more preferable that the viscosity is 1 Pa·s or less. In the specification of the present application, the melt viscosity is a value measured using a capillary rheometer under the following conditions. (Melt viscosity measurement using a capillary rheometer) The melt viscosity of PAS is measured using a capillary rheometer using about 20 g of dry polymer. As the capillary rheometer, for example, Capillograph 1-C manufactured by Toyo Seiki can be used. As the capillary, an inlet angled die of 2.095 mmφ×8.04 mmL is used. The set temperature is 330°C. A polymer sample is introduced into the apparatus and held for 5 minutes, and then the shear rate is increased to 2 sec. －１ The melt viscosity at 1000 kJ / min is measured (unit: Pa·s).

[0060] <Chlorine content of PAS> Polyarylene sulfide is produced using an aromatic compound having a halogen atom, and therefore inevitably contains a halogen atom. Depending on the application of polyarylene sulfide, the polyarylene sulfide may contain a large amount of halogen atoms, which may adversely affect the performance of products produced using polyarylene sulfide and the production equipment. Therefore, it is desirable that the halogen content, particularly the chlorine atom content, of polyarylene sulfide is low.

[0061] In the present application, the chlorine content of PAS is a value determined using combustion-ion chromatography (hereinafter, sometimes referred to as combustion IC).

[0062] <Method for measuring chlorine content> (Method for preparing combustion IC sample solution) 16 to 17 mL of water and 0.5 mL of a 3% by mass aqueous hydrogen peroxide solution are added to a combustion flask. Next, 10 mg of a dried polyarylene sulfide sample is placed in a platinum cage, and the atmosphere inside the combustion flask is replaced with an oxygen atmosphere, after which the sample is combusted in the combustion flask. Next, the combustion flask is cooled with ice, and the liquid in the combustion flask is recovered and diluted to 50 mL to obtain the sample solution. (Measurement conditions) IC column: TSKgel Super IC-AZ (inner diameter x length: 4.6 mm x 150 mm) Sample: 10 mg Heater: inlet temperature / 900°C, outlet temperature / 1000°C Absorbent: H ２ O ２900ppm, internal standard PO ４ ３－ 25 ppm

[0063] From the above viewpoints, when polyarylene sulfide is a polymer derived from dichlorobenzene, trichlorobenzene, and a sulfur source, the measurement temperature is 330°C, the shear rate is 2 sec －１ The melt viscosity measured under the conditions is defined as MV, and the chlorine content (ppm) is defined as A. Ｃｌ In this case, MV and A Ｃｌ is represented by the following formula (1), the following formula (2), and the following formula (3): A Ｃｌ ≧-1001.5×MV / 10 ５ +8850 (1) A Ｃｌ ≦-911.85×MV / 10 ５ +9400 (2) MV≧1.0×10 ５ It is preferable that (3) is satisfied.

[0064] The polyarylene sulfide may be a compound represented by the following formula (4) in addition to the formula (1), formula (2), and formula (3): Ｃｌ It is preferable that the following condition is satisfied: ≦9000.

[0065] FIG. 1 shows the relationship between the MV value and the A value for polyarylene sulfide produced while changing the melt viscosity when trichlorobenzene is added, in the cases where the conversion rate of dichlorobenzene is 93 mass%, 95 mass%, and 97 mass%, for the purpose of deriving the above formula (1) and formula (2). Ｃｌ The horizontal axis is the axis related to MV, and the vertical axis is the value of A Ｃｌ Specifically, the data of melt viscosity and chlorine content of Example 1, Examples 3 to 8, Comparative Example 1, and Comparative Examples 3 to 9 are plotted.

[0066] Of the dotted straight lines shown in FIG. 1, the dotted straight line on the upper side in the vertical axis direction is the straight line that satisfies the following formula: A Ｃｌ = -911.85 x MV / 10 ５ Of the dotted lines shown in FIG. 1, the dotted line on the lower side in the vertical axis direction is the line that satisfies the following formula: A Ｃｌ= -1001.5 x MV / 10 ５ +8850

[0067] Equation (1) is an approximate equation obtained by linearly approximating a plurality of plotted data for a dichlorobenzene conversion rate of 97% by mass using a function of Excel (registered trademark) software manufactured by Microsoft Corporation: A Ｃｌ = -1001.5 x MV / 10 ５ +8874.4. Specifically, the intercept value was changed from 8874.4 to 8850 so that the straight line on the coordinate plane corresponding to the above approximate formula was shifted downward in the vertical direction on the coordinate plane. As a result, the multiple plotted data for the case where the dichlorobenzene conversion rate was 97% by mass is located above the straight line corresponding to the following formula on the coordinate plane in the vertical direction. A Ｃｌ = -1001.5 x MV / 10 ５ +8850

[0068] Equation (2) is an approximate equation obtained by linear approximation of a plurality of plotted data for the case where the dichlorobenzene conversion rate is 95 mass % in the same manner as in equation (1): A Ｃｌ = -911.85 x MV / 10 ５ +9291.9. Specifically, the intercept value was changed from 9291.9 to 9400 so that the straight line on the coordinate plane corresponding to the above approximate formula was shifted upward in the vertical direction on the coordinate plane. As a result, the multiple plotted data for the case where the dichlorobenzene conversion rate was 95 mass% are located below the straight line corresponding to the following formula in the vertical direction on the coordinate plane. A Ｃｌ = -911.85 x MV / 10 ５ +9400

[0069] Specific data on polyarylene sulfides produced while changing the melt viscosity when the dichlorobenzene conversion rate is 93 mass%, 95 mass%, and 97 mass% will be described later in the examples.

[0070] As shown in Figure 1, the chlorine content of polyarylene sulfide produced according to the above method decreases as the melt viscosity increases. Also, Figure 1 shows that the chlorine atom content of polyarylene sulfide produced by adding trichlorobenzene when the dichlorobenzene conversion rate is 93% by mass is higher than the chlorine content of polyarylene sulfide produced by adding trichlorobenzene when the dichlorobenzene conversion rate is 95% by mass, and the chlorine content of polyarylene sulfide produced by adding trichlorobenzene when the dichlorobenzene conversion rate is 97% by mass. Furthermore, the heat of fusion of polyarylene sulfide produced by adding trichlorobenzene when the dichlorobenzene conversion rate is 93% by mass is less than 36.0 J / g. Therefore, polyarylene sulfide produced by adding trichlorobenzene when the dichlorobenzene conversion rate is 93% by mass has poor moisture resistance.

[0071] On the other hand, polyarylene sulfides produced by adding trichlorobenzene when the conversion rate of dichlorobenzene is 95% by mass or 97% by mass all satisfy the above formulas (1) to (3) and exhibit a heat of fusion of 36.0 J / g or more. Therefore, polyarylene sulfides produced by adding trichlorobenzene when the conversion rate of dichlorobenzene is 95% by mass or 97% by mass have excellent moisture resistance.

[0072] From the above, it can be said that polyarylene sulfides satisfying the above formulas (1) to (3) have excellent moisture resistance and a low chlorine atom content depending on the melt viscosity. Therefore, polyarylene sulfides satisfying the above formulas (1) to (3) are suitably used in applications requiring moisture resistance and a low halogen content.

[0073] (Melt viscoelasticity tan δ) Melt viscoelasticity tan δ is an index of dynamic viscoelasticity of a polymer. Melt viscoelasticity tan δ is known as an index of burr suppression effect, along with melt viscosity. If the melt viscoelasticity tan δ of PAS is high, the burr suppression effect is insufficient. On the other hand,２ A PAS having a melt viscoelasticity tanδ of 0.120 to 0.300 measured under atmospheric conditions at a measurement temperature of 310°C and an angular velocity ω of 1 rad / sec using parallel plates is preferably used as a flash suppressor. The melt viscoelasticity tanδ is more preferably 0.130 to 0.280, even more preferably 0.140 to 0.260, and particularly preferably 0.150 to 0.240. In the specification of this application, melt viscoelasticity is a value measured using a rotational rheometer under the following conditions. The melt viscoelasticity tanδ within the above-mentioned range can be achieved by adjusting the amount of polyhalogenated aromatic compound added and the weight-average molecular weight of the prepolymer used when adding the polyhalogenated aromatic compound in the above-mentioned PAS production method to fall within the above-mentioned preferred range. (Melt Viscoelasticity tanδ Measurement Method) 3 g of polyarene sulfide is hot-pressed at 340°C in a circular mold having a diameter of 2 cm and a thickness of 3 mm to prepare a test piece. The obtained test piece was ２ The melt viscoelasticity (tan δ) is measured in an atmosphere at a measurement temperature of 310° C. using parallel plates at an angular velocity ω=1 rad / sec.

[0074] The present invention is not limited to the above-described embodiments, and various modifications are possible. Embodiments obtained by appropriately combining the technical means disclosed in the specification of this application are also included in the technical scope of the present invention. In addition, all documents described in the specification of this application are incorporated by reference.

[0075] The present invention will be described in more detail below with reference to examples and comparative examples. The methods for measuring various characteristics and physical properties are as follows.

[0076] (1) Melt Viscosity The melt viscosity of the polymer was measured using approximately 20 g of dry polymer using a Capillograph 1-C manufactured by Toyo Seiki Seisaku-sho. In this case, a capillary with an inlet angle of 2.095 mmφ×8.04 mmL was used, and the set temperature was 330°C. The polymer sample was introduced into the apparatus and held for 5 minutes, and then heated at a shear rate of 2 sec. －１ The melt viscosity at 1000 kJ / min was measured (unit: Pa·s).

[0077] (2) Heat of fusion Heat of fusion was measured under the following conditions using a differential scanning calorimeter (DSC) manufactured by METTLER. The amount of sample used for the measurement was 8 mg to 12 mg. The heat of fusion was measured based on the melting peak observed during the second temperature increase (second cycle) from 50°C to 340°C. The reason for using the second data is to obtain the measured value after the particles have been melted and the adhesion of the sample stage (aluminum pan) has been ensured. <Measurement conditions> Temperature profile: 1) 50°C 2) Heat to 340°C at a rate of 10°C / min 3) Hold at 340°C for 1 minute 4) Cool to 50°C at a rate of 10°C / min 5) Heat to 340°C at a rate of 10°C / min Atmosphere: N ２ Atmospheric atmosphere (to prevent oxidation reactions)

[0078] (3) Moisture Resistance Moisture resistance was evaluated based on the storage modulus retention calculated from the storage modulus before and after a pressure cooker test (PCT) using the following formula. The storage modulus retention was determined using the storage modulus at 60°C. Storage modulus retention (%) = storage modulus (after PCT) / storage modulus (before PCT) × 100

[0079] First, polyarylene sulfide was filled into a 1 mm thick mold, and the mold was hot-pressed at 340°C. The hot-pressed polyarylene sulfide sheet was annealed at 140°C for 1 hour. The annealed sheet was cut to obtain a test piece measuring 5 mm wide x 15 mm long x 1 mm thick. Multiple test pieces were obtained in the same manner. The storage modulus at 60°C of the obtained test pieces was measured under the following conditions. Next, a test piece other than the test piece used for measuring the storage modulus was placed in an autoclave filled with water at a position not in contact with the water. Next, the sealed autoclave was heated at 120°C for 20 hours to perform PCT. After heating, the storage modulus (tan δ) of the test piece after PCT was measured at 60°C under the following conditions.

[0080] (Storage modulus measurement) Apparatus: DMS6100 manufactured by SII Nano Technology Co., Ltd. Measurement mode: Tension Atmosphere: N ２Atmosphere Temperature profile: 50°C to 240°C at a rate of 2°C / min Strain amplitude: 5 μm Tension / compression force gain: 1.5 Force amplitude initial value: 200 Frequency: 1 Hz Data sampling interval: 3 seconds

[0081] (4) Chlorine Atom Content The chlorine atom content of the polyarylene sulfide was measured by combustion-ion chromatography (combustion IC).

[0082] (Combustion IC) First, 16 to 17 mL of water and 0.5 mL of a 3% by mass aqueous solution of hydrogen peroxide were added to a combustion flask. Next, 10 mg of a polyarylene sulfide sample was placed in a platinum cage. After the atmosphere in the combustion flask was replaced with an oxygen atmosphere, the sample in the platinum cage was combusted in the combustion flask. Next, the combustion flask was cooled with ice, and the liquid in the combustion flask was recovered. The recovered liquid was diluted to 50 mL. Ion chromatography analysis was performed using the diluted liquid as a sample, and the chlorine atom content, corrected by a blank, was determined. (Measurement conditions) Ion chromatograph: DX320 manufactured by DIONEX Combustion pretreatment device: AQF-100, ABC, WS-100, GA-100 manufactured by Mitsubishi Chemical Sample amount: 10 mg Heater temperature: inlet 900°C, outlet 1000°C Absorption liquid: H ２ O ２ 900ppm, internal standard PO ４ ３－ 25 ppm

[0083] (5) Measurement of Melt Viscoelasticity (tan δ) 3 g of polyarene sulfide was hot-pressed at 340°C in a circular mold having a diameter of 2 cm and a thickness of 3 mm to prepare a test piece. ２ The melt viscoelasticity (tan δ) was measured in an atmosphere at a measurement temperature of 310° C. using parallel plates at an angular velocity ω=1 rad / sec.

[0084] Example 1 1. Dehydration step: A sodium hydrosulfide (NaSH) aqueous solution was used as the sulfur source. 5,995 g of N-methyl-2-pyrrolidone (hereinafter abbreviated as "NMP"), 2,009 g of a 62.37 mass% aqueous sodium hydrosulfide solution, and 1,141 g of a 73.43 mass% aqueous sodium hydroxide solution were placed in a 20-liter autoclave (reaction vessel). When the sulfur source consisting of sodium hydrosulfide and sodium sulfide is represented as "S," the molar ratio (mol / mol) of sodium hydroxide / sulfur source (NaOH / S) was 0.96.

[0085] After the atmosphere inside the reactor was replaced with nitrogen gas, the temperature inside the reactor was gradually raised to 200°C over about 3 hours while stirring at a rotation speed of 250 rpm. After the temperature was raised, water (H ２ 914 g of NMP, 806 g of hydrogen sulfide (H ２ S) 13.64 g (0.40 mol) was distilled from the reactor.

[0086] 2. Charging step: After the dehydration step, the reactor was cooled to a temperature of 170°C. Next, at the same temperature, 3282 g of p-dichlorobenzene (hereinafter abbreviated as "pDCB"), 2813 g of NMP, 4.2 g of sodium hydroxide with a purity of 99%, and 77.5 g of water were added to the reactor to prepare a charging mixture. The temperature inside the reactor after preparing the charging mixture was 140°C. The ratio of NMP / S (g / mol) in the reactor was 365, and pDCB / S (mol / mol) was 1.066. ２ The O / S (mol / mol) was 1.50 and the NaOH / S (mol / mol) was 1.00.

[0087] 3. Polymerization Step: (Pre-Stage Polymerization Step) The temperature inside the reactor was raised to 220°C while stirring the charged mixture by rotating the agitator attached to the reactor at 250 rpm. The reaction was carried out at 220°C for 1 hour, followed by a reaction at 230°C for 2 hours. After the reaction had continued for 2 hours at 230°C, 1,2,4-trichlorobenzene (TCB) was added to the reaction mixture so that the ratio of the number of moles of TCB to the number of moles of sulfur source (S) was 0.03 mol / mol in terms of TCB / S. After the addition of TCB, 329 g of NMP was added to the reactor. After the addition of NMP, the reaction was carried out for an additional 0.25 hours at 220°C. The conversion of pDCB upon the addition of TCB was 95% by mass. The conversion was measured by the method described in the specification. The weight-average molecular weight of the prepolymer upon the addition of TCB was 15,000 g / mol. The weight average molecular weight was measured by the method described in the specification.

[0088] (Phase separation step and second-stage polymerization step) After the first-stage polymerization step, the rotation speed of the stirrer was increased to 400 rpm, and while continuing stirring, 474 g of water as a phase separation agent and an aqueous sodium hydroxide solution consisting of 25 g of 99% sodium hydroxide were pressure-charged into the reactor. After pressure-charge, the total amount of water / NMP in the reactor was 7.3 (mol / kg), the total amount of water / available S in the reactor was 2.7 (mol / mol), and the NaOH / S in the reactor was 1.028 (mol / mol). Next, when the temperature of the reaction mixture was raised to 255 ° C, the reaction mixture formed a phase-separated state. Thereafter, the polymerization reaction was carried out for 2 hours while maintaining the temperature at 255 ° C.

[0089] 4. Post-treatment step: After the reaction was completed, the reaction mixture was cooled to near room temperature, and the reaction solution was passed through a 100-mesh screen to sieve the granular polymer. The separated polymer was washed twice with acetone, three times with water, then with 0.3% acetic acid, and four times with water to obtain a washed polymer. The washed polymer was then dried at 130°C for 3 hours. The melt viscosity, heat of fusion, storage modulus retention, chlorine atom content, and melt viscoelasticity (tan δ) of the PAS thus obtained were measured and the results are shown in Table 1. The ratio of the mass of particles that did not pass through the 100-mesh (opening diameter 150 μm) screen to the total mass of the recovered PAS was 89.0 mass%.

[0090] Example 2 PAS was obtained in the same manner as in Example 1, except that the reaction time in the first-stage polymerization step was changed from 2.0 hours to 2.25 hours, thereby setting the conversion rate of pDCB at the time of adding TCB to 96% by mass. The weight-average molecular weight of the prepolymer at the time of adding TCB was 15,500 g / mol. The melt viscosity, heat of fusion, retention of storage modulus, chlorine atom content, and melt viscoelasticity (tan δ) of the PAS thus obtained were measured and the results are shown in Table 1. The ratio of the mass of particles that did not pass through a 100-mesh (opening diameter 150 μm) screen to the total mass of the recovered PAS was 89.1% by mass.

[0091] Comparative Example 1 PAS was obtained in the same manner as in Example 1, except that the reaction time in the first-stage polymerization step was changed from 2.0 hours to 1.5 hours, thereby setting the conversion rate of pDCB at the time of adding TCB to 93% by mass. The weight-average molecular weight of the prepolymer at the time of adding TCB was 12,500 g / mol. The melt viscosity, heat of fusion, retention of storage modulus, chlorine atom content, and melt viscoelasticity (tan δ) of the PAS obtained in this manner were measured and the results are shown in Table 1.

[0092] Comparative Example 2 A PAS was obtained in the same manner as in Example 1, except that the amount of water added as a phase separation agent was changed from 474 g to 297 g. The weight-average molecular weight of the prepolymer when TCB was added was 15,500 g / mol. The melt viscosity, heat of fusion, retention of storage modulus, chlorine atom content, and melt viscoelasticity (tan δ) of the PAS thus obtained are shown in Table 1.

[0093] According to Table 1, when the conversion rate of pDCB is 95% or more and the amount of water / available sulfur source (mol / mol) in the reaction mixture after adding the phase separation agent is 2.30 or more, the addition of TCB results in a heat of fusion of 36.0 J / g or more and a reaction rate of 1.0 × 10 ５ It can be seen that polyarylene sulfides having a melt viscosity of 36.0 J / g or more can be obtained. Furthermore, Table 1 shows that the polyarylene sulfides of the Examples having a heat of fusion of 36.0 J / g or more exhibit high storage modulus retention, are less susceptible to the influence of PCT, and have excellent moisture resistance. Furthermore, the chlorine atom content of the polyarylene sulfides of the Examples is lower than the chlorine atom content of the polyarylene sulfides of the Comparative Examples having similar melt viscosities.

[0094] [Example 1 and Examples 3 to 6] Polyarylene sulfides of Examples 3 to 6 were obtained in the same manner as in Example 1, except that the time for the second-stage polymerization was changed. The melt viscosity and chlorine atom content of the obtained polyarylene sulfides are shown in Table 2. The heat of fusion of the polyarylene sulfides of Examples 3 to 6 was 36.0 J / g or more.

[0095] [Example 7] PAS was obtained in the same manner as in Example 1, except that the reaction time in the first-stage polymerization step was changed from 2.0 hours to 2.5 hours, thereby setting the conversion rate of pDCB at the time of adding TCB to 97% by mass. The weight-average molecular weight of the prepolymer at the time of adding TCB was 16,500 g / mol. The melt viscosity and chlorine atom content of the obtained polyarylene sulfide are shown in Table 2. The heat of fusion of the polyarylene sulfide of Example 7 was 36.0 J / g or more.

[0096] [Example 8] Polyarylene sulfide of Example 8 was obtained in the same manner as in Example 7, except that the time for the second-stage polymerization was changed. The melt viscosity and chlorine atom content of the obtained polyarylene sulfide are shown in Table 2. The heat of fusion of the polyarylene sulfide of Example 8 was 36.0 J / g or more.

[0097] [Comparative Examples 3 to 9] Polyarylene sulfides of Comparative Examples 3 to 9 were obtained in the same manner as in Comparative Example 1, except that the time for the second-stage polymerization was changed. The melt viscosity and chlorine atom content of the obtained polyarylene sulfides are shown in Table 2. The heat of fusion of the polyarylene sulfides of Comparative Example 1 and Comparative Examples 3 to 9 was less than 36.0 J / g.

[0098]

[0099] The data shown in Table 2 was plotted in the graph shown as Figure 1. The interpretation of the graph shown as Figure 1 has been described above.

Claims

1. Exhibits a heat of fusion of 36.0 J / g or more, measured at a temperature of 330°C and a shear rate of 2 sec －１ The melt viscosity measured under the conditions is 1.0 × 10 ５ Polyarylene sulfide having a viscosity of Pa·s or more.

2. The polyarylene sulfide is a polymer derived from dichlorobenzene, trichlorobenzene, and a sulfur source, and the melt viscosity is represented by MV and the chlorine content (ppm) is represented by A. Ｃｌ In this case, the MV and the A Ｃｌ is represented by the following formula (1), the following formula (2), and the following formula (3): A Ｃｌ ≧-1001.5×MV / 10 ５ +8850 (1) A Ｃｌ ≦-911.85×MV / 10 ５ +9400 (2) MV≧1.0×10 ５ The polyarylene sulfide according to claim 1, which satisfies the above formula (3).

3. Furthermore, the following formula (4): 4000≦A Ｃｌ The polyarylene sulfide according to claim 2, which satisfies the following: ≦9000

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