JP6780373B2 - Method for producing high-purity polyarylene sulfide particles - Google Patents

Description

The present invention relates to a method for producing polyarylene sulfide. More specifically, the present invention relates to a method for easily and efficiently recovering high-purity polyarylene sulfide particles.

Polyphenylene sulfide (hereinafter, may be abbreviated as PAS) represented by polyphenylene sulfide (hereinafter, may be abbreviated as PPS) has excellent heat resistance, barrier property, chemical resistance, and electrical insulation. It is a resin having properties suitable as engineering plastics such as moisture resistance and heat resistance and flame retardancy. In addition, it can be molded into various molded parts, films, sheets, fibers, etc. by injection molding and extrusion molding, and is widely used in fields where heat resistance and chemical resistance are required, such as various electrical / electronic parts, mechanical parts, and automobile parts. Has been done.

As a specific method for producing this PAS, an alkali metal sulfide such as sodium hydrosulfide and p-dichlorobenzene in an organic amide solvent such as N-methyl-2-pyrrolidone (hereinafter, may be abbreviated as NMP). A method of reacting with a dihalogenated aromatic compound such as the above has been proposed (see, for example, Patent Document 1), and this method is widely used as an industrial production method of PAS. Since the polymerization reaction in this production method is a desalting polycondensation mechanism, a large amount of by-product salt such as sodium chloride is produced. Therefore, a step of removing the by-product salt is required after the polymerization reaction, but it is difficult to completely remove the by-product salt by a normal treatment, and an inorganic component is contained in a general manufacturing process. If an inorganic component remains in the PAS produced in this way, there may be a problem that physical properties such as electrical characteristics are deteriorated. Therefore, in order to apply such a molded product using PAS as a raw material to the field of electrical and electronic parts, it is necessary to use PAS that has been sufficiently washed to reduce the amount of inorganic components, which is large in terms of cost. There was a challenge.

Further, the PAS obtained by such a production method contains highly volatile components such as raw materials for producing PAS, by-products produced in the process of producing and recovering PAS, and low molecular weight components such as oligomers as organic impurities. , A large amount of gas is generated when this PAS is melted or used at a high temperature. As a result, volatile components adhere to the inside of the injection molding machine when it is melted and used in injection molding, etc., which increases the manufacturing cost due to the increased number of maintenances and generates gas when the molded product is used at a high temperature. Problems such as causing some defects may occur. Therefore, it is necessary to produce PAS in which organic impurities such as highly volatile low molecular weight PAS are sufficiently reduced as well as inorganic components.

Various methods for reducing the above-mentioned problems in PAS, that is, the amount of inorganic impurities contained in PAS and the amount of organic impurities have been studied so far. For example, PPS containing impurities obtained by the above method is added to a cleaning solution and stirred. After that, the method of filtering and cleaning (hereinafter, this method may be referred to as reslurry cleaning) is repeatedly carried out at 70 ° C. (see, for example, Patent Document 2), sodium hydrogen sulfide, sodium hydroxide and p. -A method in which a reactant containing PPS obtained by reacting dichlorobenzene in NMP is subjected to a centrifugation operation at room temperature, NMP is added to the settling cake, and the centrifugation operation is repeated (see, for example, Patent Document 3). After immersing in water and warm water and stirring, washing to obtain solid content by filtration is repeated with an acidic aqueous solution and ion-exchanged water (see, for example, Patent Document 4), and a wet cake containing PPS resin fine particles as solid content is used as an interface. A method of substituting a mother liquor with a dispersion solvent by repeating stirring and filtering in addition to a dispersion solvent in which an activator is present (see, for example, Patent Document 5) is disclosed.

On the other hand, as a method for producing PAS having a small amount of impurities contained, a method using cyclic polyarylene sulfide (hereinafter, may be abbreviated as cyclic PAS) can be mentioned.

Aromatic cyclic compounds typified by cyclic PAS have been attracting attention in recent years due to their cyclic properties, that is, their specificity derived from their structure. Specifically, it can be applied to high-performance materials, for example, it can be used as a compound with inclusion ability, or it can be used as an effective monomer for the synthesis of high molecular weight linear polymers by ring-opening polymerization. Etc. are expected.

As a method for producing a PAS containing a small amount of impurities using this cyclic PAS, a sulfidizing agent and a dihalogenated aromatic compound are brought into contact with each other in an organic polar solvent to produce a cyclic PAS, and the separated cyclic PAS is melted. Examples thereof include a method of polymerizing to increase the molecular weight (see, for example, Patent Document 6). In this method, by separating the cyclic PAS from the raw material and its reaction by-product once and then performing melt polymerization, it is possible to reduce the amount of inorganic impurities and organic impurities contained as compared with general PAS. Therefore, it is important to separate the cyclic PAS with less impurities with high purity. As this separation method, a cyclic PAS is extracted from a mixture containing at least a cyclic PAS and a linear PAS with an organic solvent, the organic solvent is distilled off to obtain a solid content, and then the mixture is again slurryed with an organic solvent to prepare a poor solvent. A method for recovering cyclic PAS that reprecipitates in (see, for example, Patent Document 7) and solid-liquid separation by adding a solvent on a separation filter in which a solid content cake composed of a mother liquor and a cyclic PAS containing impurities is laminated (hereinafter, , This method may be referred to as “washing”), and the like (see, for example, Patent Document 8) are disclosed.

Japanese Unexamined Patent Publication No. 7-003022 JP-A-2015-218214 Japanese Unexamined Patent Publication No. 2005-264018 Japanese Unexamined Patent Publication No. 2014-74186 Japanese Unexamined Patent Publication No. 2014-24957 Japanese Unexamined Patent Publication No. 2015-10758 JP-A-2009-030012 Japanese Unexamined Patent Publication No. 2014-108921

Regarding the removal of impurities contained in PAS, the method described in Patent Documents 1 to 4 is a method of removing impurities from PAS by contacting PAS and a mixture containing impurities with a liquid and dissolving inorganic impurities and organic impurities in the liquid. Since it is used, it requires several steps and long-term cleaning with a large amount of solvent to remove impurities, and therefore it is a method that requires an extremely large-scale and complicated process. Further, it is necessary to treat a large amount of aqueous wastewater generated in this cleaning process, and there is a problem that the process cost and the environmental load are extremely large.

Further, in the reslurry cleaning described in Patent Document 4, impurities in the solution can be reduced by diluting the solution containing impurities in the cake with a cleaning liquid and performing cake filtration, but the impurities are significantly reduced by the dilution. A large amount of cleaning solution is required to reduce the amount (for example, theoretically, in order to reduce the concentration of the liquid in the cake to 1/100, the amount of cleaning solution is 99 times the original liquid weight). Further, a small amount of cleaning liquid (for example, 10 times or less the weight of the liquid in the cake) has a drawback that the dispersibility of the cake in the cleaning liquid tends to decrease and the cleaning efficiency tends to decrease.

Further, also in the manufacturing method using the cyclic PAS, it has been a big problem to separate the linear PAS and the cyclic PAS in each step with high purity. The method described in Patent Document 7 in which a good solvent is extracted, then slurryed again with a good solvent and reprecipitated with a poor solvent has excellent separation accuracy, but is complicated as a process surface such as extraction, slurrying, and reprecipitation. There was a demerit that a process was required and the production cost increased. Further, the method of laminating solid content cakes on a filter and performing washing by stacking the solid content cake described in Patent Document 8 is realistic and low process cost in that washing can be easily performed, but there is no description of examples and the like. The specific operation is unknown, and a production method including a method for cleaning PAS particles, which can be easily performed in the process and has high cleaning efficiency, has not been established.

Therefore, an object of the present invention is to solve the above-mentioned problems of the prior art and to provide a method for producing high-purity polyarylene sulfide particles having a reduced impurity component, and more specifically, a cake containing PAS particles and a liquid. The present invention relates to a method for producing high-purity PAS particles by more efficiently cleaning impurities contained in the above with a small amount of cleaning liquid.

The present invention employs the following means for the above problems.
That is, the present invention
[1] A cake (c) containing at least polyarylene sulfide particles (a) and a liquid (b) is formed at a density of 800 kg / m ³ or more, and the filtrate (e) is simultaneously supplied to the cake (c). A method for producing high-purity polyarylene sulfide particles, which comprises discharging d) and washing the polyarylene sulfide particles (a) .
The content of the polyarylene sulfide particles (a) in the cake (c) is 25% by weight or more and 90% by weight or less.
A manufacturing method in which the amount of the cleaning liquid (e) is 0.5 times or more and 1 times or less the liquid amount of the liquid (b).
[2] Discharge rate V ₁ [kg / (sec · m ² )] of the filtrate (d) discharged from the filtration surface on which the cake (c) is installed, and the supply rate of the cleaning liquid (e) to the cake (c). The method for producing high-purity polyarylene sulfide particles according to [1], wherein V ₂ [kg / (sec · m ² )] satisfies the following formula 1.
ΔV = | V ₁ −V ₂ | / V ₁ ≦ 0.2 ・ ・ ・ Equation 1
[3] The method for producing high-purity polyarylene sulfide particles according to any one of [1] and [2], wherein the cake (c) has a thickness of 2 mm or more and 50 mm or less.
[4] The method for producing high-purity polyarylene sulfide particles according to any one of [1] to [3], wherein at least one selected from water and an organic solvent is used as the cleaning liquid (e).
[ 5 ] The method for producing high-purity polyarylene sulfide particles according to any one of [1] to [ 4 ], wherein the replacement rate of the liquid (b) is 70% or more and 100% or less.
[6] The content of the cyclic polyarylene sulfide in the polyarylene sulfide particles (a) is 50 wt% or more, and characterized in that 100 wt% or less from the [1] according to any one of [5] A method for producing high-purity polyarylene sulfide particles.

According to the present invention, it is possible to provide a method for easily and efficiently recovering high-purity polyarylene sulfide particles having reduced inorganic and organic impurities. The polyarylene sulfide particles thus obtained (hereinafter, may be abbreviated as PAS particles) or the obtained PAS particles (a) containing cyclic PAS as a main component are melt-polymerized to increase the molecular weight. The molten polymer exhibits excellent properties of polyarylene sulfide, which has less deterioration in physical properties such as electrical insulation and a small amount of gas generated. Further, even a very small amount of the cleaning liquid (e), which is 10 times or less the weight of the liquid (b), can be cleaned with high cleaning efficiency, and the amount of the cleaning liquid can be significantly reduced. As a result, the equipment size of the process can be reduced, energy loss can be suppressed when a process such as solvent recovery is provided, and a process with reduced production cost can be provided.

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

A cake (c) containing at least polyarylene sulfide particles (a) and a liquid (b) is formed at a density of 800 kg / m ³ or more, and the filtrate (d) is fed at the same time as the cleaning liquid (e) is supplied to the cake (c). The present invention relates to a method for producing high-purity polyarylene sulfide particles, which comprises discharging and washing the polyarylene sulfide particles (a).

[Polyarylene sulfide]
PAS in the present invention is a chemical formula (a).

It is a homopolymer or copolymer having the repeating unit shown in the above as a main constituent unit, or a cyclic compound.

Examples of Ar include chemical formulas (a) to (d).

(However, R1 and R2 in the formula are substituents selected from hydrogen, an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, and a halogen group, and R1 and R2 are the same but different. May be good.)

As long as this repetition is the main constituent unit, even if the branched structure or crosslinked structure represented by the chemical formulas (e) to (g) and the copolymerization component represented by the chemical formulas (ku) to (ta) are randomly contained. It may be contained in blocks, or it may be any mixture thereof. The amount of these copolymerizations is preferably in the range of 0 to 1 mol% with respect to 1 mol of the unit of the chemical formula (a).

A particularly preferable PAS is the chemical formula (chi) as the main constituent unit of the polymer.

In addition to PPS containing 80 mol% or more, particularly 90 mol% or more, polyphenylene sulfide sulfone and polyphenylene sulfide ketone can be mentioned. Among the PASs mentioned so far, those having no cyclic structure are particularly called linear PASs, and are distinguished in the present invention.

Next, among the above PAS, the PAS having a cyclic structure is called a cyclic PAS, and the cyclic PAS is a compound such as the following chemical formula (tsu) containing 80 mol% or more of the repeating unit of the above chemical formula (a). Can be exemplified.

A particularly preferable cyclic PAS is a p-phenylene sulfide unit as a main constituent unit.

A cyclic PPS containing 80 mol% or more, particularly 90 mol% or more.

The number of repetitions m in the above chemical formula (tsu) of the cyclic PAS is not particularly limited, but a mixture of 4 to 50 is preferable, 4 to 25 is more preferable, and 4 to 20 is further preferable. Since the temperature of the cyclic PAS having m in such a range tends to be low when heated, the processing temperature is lowered when the cyclic PAS is molded or melt-kneaded with other resins. It is advantageous from the viewpoint of being able to do it. Further, when converting the cyclic PAS into a high degree of polymerization by melt polymerization, it is preferable to heat the cyclic PAS to a temperature higher than the temperature at which the cyclic PAS melts, but as m increases, the melting temperature of the cyclic PAS increases. Therefore, it is advantageous to set m in the above range from the viewpoint that the conversion of PAS to a high degree of polymerization can be performed at a lower temperature. Further, the cyclic PAS of the present invention may be either a single compound having a single repetition number or a mixture of cyclic PAS having different repetition numbers, but the mixture of cyclic PAS having different repetition numbers is simpler. It is preferable because the melting solution temperature is lower than that of a single compound having one repetition number, and the amount of heat required for melting tends to be smaller.

The molecular weight of the PAS of the present invention is not particularly limited, and the weight average molecular weight of a general PAS can be exemplified by 400 to 1,000,000. Regarding linear PAS, those having a weight average molecular weight of less than 5,000 are simply linear PAS oligomers (hereinafter, may be referred to as oligomers), and those having a weight average molecular weight of 5,000 or more are simply referred to. It can be called a linear PAS.

The PAS particle (a) in the present invention is a solid component composed of the linear and / or cyclic PAS. When either the linear or cyclic PAS occupies 50% by weight or more of the PAS particles (a), the PAS is referred to as the main component of the PAS particles (a).

The average particle size of the PAS particles (a) is not particularly limited, but if the particle size is small, the filtration rate may decrease due to clogging of the filter medium or filtration cannot be performed when the PAS particles (a) are isolated. There is a possibility that particles may flow out from the filter medium to the filtrate side. Further, if the particle size is large, it becomes difficult to increase the density when compressing the cake (c) to increase the density, so the average grain shape is preferably 100 nm to 1 mm.

The present invention relates to a method for producing high-purity polyarylene particles by washing with a cake (c) containing at least the PAS particles (a) and the liquid (b).

[Recovery of cake (c)]
The cake (c) used in the present invention may be any cake as long as it contains at least PAS particles (a) and liquid (b) and exhibits solid behavior. In order for the cake to maintain its solid behavior, it is necessary for PAS particles (a) that are not dissolved in the liquid (b) to be present. Therefore, it is desirable that the content of the PAS particles (a) in the cake (c) is 25% by weight or more. More preferably, it is 30% by weight or more. The upper limit is 90% by weight or less, preferably 80% by weight or less, and more preferably 70% by weight or less. Similarly, the amount of the liquid (b) is 10% by weight or more as the lower limit, preferably 20% by weight or more, more preferably 30% by weight or more, and the upper limit is 75% by weight or less and 70% by weight or less. preferable. The content of PAS particles (a) in the cake is calculated as a ratio of the weight when the liquid (b) is completely removed from the cake (c) divided by the weight of the original cake (c). Can be done.

Further, it is desirable that the cake (c) and the PAS particles (a) and the liquid (b) do not contain impurities, and the smaller the impurity content, in other words, the higher the purity, the more the isolated PAS particles (a). Alternatively, the characteristics of the molten polymer obtained by melt-polymerizing the PAS particles (a) containing cyclic PAS as a main component to increase the molecular weight will be more exhibited. Conventionally, in order to obtain high-purity PAS particles (a), a large amount of labor and energy have tended to be required, but in the present invention, high-purity PAS particles (a) can be obtained more easily. Therefore, the cake (c) and the PAS particles (a) and the liquid (b) may contain impurities as long as the essence of the present invention is not impaired.

Here, the impurities in the present invention refer to components other than the PAS component to be obtained, and are not particularly limited. Examples of inorganic impurities include substances such as salts and metals, and the amount of the impurities is PAS particles. It can be easily evaluated by the ash content of (a). Examples of organic impurities include raw materials and oligomers for producing PAS, compounds produced by modification in the process of producing and recovering PAS, and the like, and one of the simple evaluation methods is measurement of the amount of generated gas. Further, the state in which these impurities are reduced is called high purity.

The liquid (b) is not limited as long as it does not impair the essence of the cake (c) described above, but mainly one kind of solvent or a plurality of solvents used at the time of preparation and recovery of the cake (c) described later. Consists of a complex liquid of. Examples of the solvent used for the preparation and recovery of the cake (c) include an organic polar solvent, and among them, an organic amide solvent. 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, 1, Aprotic organic solvents such as 3-dimethyl-2-imidazolidinone, N, N-dimethylacetamide, N, N-dimethylformamide, and hexamethylphosphoric acid triamide, and mixtures thereof, have stable reactions. It is preferably used because it is expensive. Of these, N-methyl-2-pyrrolidone is particularly preferably used. In addition to organic polar solvents, for example, water, methanol, ethanol, propanol, isopropanol, butanol, alcohols typified by hexanol, acetone, ketones typified by methyl ethyl ketone, ethyl acetate, acetic acid typified by butyl acetate. Esters can be exemplified, and water is particularly preferable.

If the cake (c) corresponds to the above, the preparation method and recovery method are not limited. An example of a cake recovery method is shown below.

<Recovery of cake (c) containing PAS particles (a) containing linear PAS as a main component>
As an example of the method for obtaining the cake (c) containing the PAS particles (a) containing linear PAS as a main component, as described in JP-A-2014-74186, at least a sulfidizing agent and a dihalogenated aromatic compound are used. Examples thereof include a method of producing and recovering a cake from a polymerization reaction product by carrying out a polymerization reaction in an organic polar solvent by using a quenching method, a flash method or the like. The cake thus obtained can be used in the present invention as a cake (c).

<Recovery of cake (c) containing PAS particles (a) containing cyclic PAS as a main component>
As an example of a method for obtaining a cake (c) containing PAS particles (a) containing cyclic PAS particles as a main component, as described in Japanese Patent Application Laid-Open No. 2015-10758, a sulfidizing agent and a dihalogenated aromatic are used. A reaction mixture (A) containing at least cyclic PAS and linear PAS, which is obtained by contacting and reacting the compounds in the above-mentioned organic polar solvent, is obtained. The reaction mixture (A) can be separated into a cake containing PAS particles (a) containing linear PAS as a main component and a filtrate (B) by solid-liquid separation, and this cake is also used in the present invention as a cake (c). be able to. Further, by removing the organic polar solvent from the filtrate (B), a cake (c) containing PAS particles (a) containing cyclic PAS as a main component can be obtained.

Hereinafter, preferred embodiments of each step will be described in detail.

<(1) Method for preparing reaction mixture (A)>
Hereinafter, a preferred embodiment of a method for obtaining a reaction mixture (A) by contacting a sulfidizing agent with a dihalogenated aromatic compound in an organic polar solvent and reacting them will be described in detail.

The dihalogenated aromatic compound is an aromatic compound having an arylene group which is a divalent group of an aromatic ring and two halogeno groups. For example, as a compound having a phenylene group which is a divalent group of a benzene ring as an arylene group and having two halogeno groups, p-dichlorobenzene, o-dichlorobenzene, m-dichlorobenzene, p-dibromobenzene and o-dibromo Examples thereof include dihalogenated benzene such as benzene, m-dibromobenzene, 1-bromo-4-chlorobenzene, and 1-bromo-3-chlorobenzene. Further, examples of the dihalogenated aromatic compound include 1-methoxy-2,5-dichlorobenzene, 1-methyl-2,5-dichlorobenzene, 1,4-dimethyl-2,5-dichlorobenzene and 1,3-dimethyl. Examples thereof include compounds containing substituents other than halogen such as -2,5-dichlorobenzene and 3,5-dichlorobenzoic acid. Of these, a dihalogenated aromatic compound containing p-dihalogenated benzene as a main component, typified by p-dichlorobenzene, is preferable. Particularly preferably, it contains 80 to 100 mol% of p-dichlorobenzene, and more preferably 90 to 100 mol%. It is also possible to use two or more different dihalogenated aromatic compounds in combination in order to obtain a cyclic polyarylene sulfide copolymer.

The sulfidizing agent may be any one capable of introducing a sulfide bond into the dihalogenated aromatic compound, and examples thereof include alkali metal sulfide, alkali metal hydrosulfide, and hydrogen sulfide. 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. Of these, lithium sulfide and / or sodium sulfide are preferable, and sodium sulfide is more preferably used. These alkali metal sulfides can be used as hydrates or aqueous mixtures, or in the form of anhydrides. The 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. Since inexpensive alkali metal sulfides that are generally available are hydrates or aqueous mixtures, it is preferable to use alkali metal sulfides in this form. Specific examples of alkali metal hydrosulfides include lithium hydrosulfide, sodium hydrosulfide, potassium hydrosulfide, lithium hydrosulfide, rubidium hydrosulfide, cesium hydrosulfide, and mixtures of two or more of these. Of these, lithium hydrosulfide and / or sodium hydrosulfide are preferable, and sodium hydrosulfide is more preferably used.

The amount of the dihalogenated aromatic compound used is preferably in the range of 0.9 to 2.0 mol, more preferably 0.95 to 1.5 mol, per 1 mol of the sulfur component of the sulfidizing agent. A range of .005 to 1.2 mol is more preferred. The whole amount of the dihalogenated aromatic compound may be reacted at one time, or may be divided and subjected to the reaction as described in, for example, International Publication No. 2013/061561.

The reaction temperature when the sulfidizing agent and the dihalogenated aromatic compound are brought into contact with each other and reacted cannot be uniquely determined because they vary depending on the type and amount of the organic polar solvent, but are usually 120 to 350 ° C., preferably 120 to 350 ° C. The range of 180 to 320 ° C., more preferably 220 to 310 ° C., still more preferably 225 to 300 ° C. can be exemplified. In this preferred temperature range, a higher reaction rate is obtained and the reaction tends to proceed uniformly. Further, the reaction may be a one-step reaction performed at a constant temperature, a multi-step reaction in which the temperature is raised stepwise, or a reaction in which the temperature is continuously changed.

The reaction time is not limited because it depends on the type and amount of the raw materials used or the reaction temperature, but is preferably 0.1 hours or more, more preferably 0.5 hours or more. By setting the time to this preferable time or longer, the unreacted raw material component can be sufficiently reduced, so that the produced cyclic polyarylene sulfide tends to be easily recovered. On the other hand, although there is no particular upper limit to the reaction time, the reaction proceeds sufficiently even within 40 hours, and preferably 10 hours or less, more preferably 6 hours or less can be adopted.

As a method of contacting the sulfidating agent with the dihalogenated aromatic compound to react, various known polymerization methods and reaction methods such as a batch method and a continuous method can be adopted. Further, the atmosphere in the production is preferably a non-oxidizing atmosphere, preferably an atmosphere of an inert gas such as nitrogen, helium, and argon, and preferably a nitrogen atmosphere from the viewpoint of economy and ease of handling. The non-oxidizing atmosphere is 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 substantially no oxygen, that is, an atmosphere of an inert gas such as nitrogen, helium, or argon. Of these, it is preferable to carry out in a nitrogen atmosphere from the viewpoint of economy and ease of handling.

<(2) Solid-liquid separation>
Hereinafter, the method for obtaining the reaction mixture (A) by solid-liquid separation into a cake (c) containing PAS particles (a) containing linear PAS as a main component and a filtrate (B) is preferable. Aspects will be described in detail.

The temperature for solid-liquid separation is not particularly limited as long as it is equal to or lower than the boiling point of the organic polar solvent at normal pressure, but is preferably in the range of 10 ° C to 200 ° C, more preferably in the range of 15 ° C to 180 ° C, and to 20 ° C to 20 ° C. The range of 150 ° C. is even more preferable, the range of 20 ° C. to 120 ° C. is even more preferable, and the range of 20 ° C. to 90 ° C. is particularly preferable. In the above range, the cyclic PAS is soluble in the organic polar solvent, but the linear PAS tends to be difficult to dissolve in the organic polar solvent. Therefore, by performing solid-liquid separation in the above temperature range, it is possible to separate most of the linear PAS as a solid component from the reaction mixture (A), and this solid component is recovered as a cake (c). It can also be used in inventions. Further, when the temperature at which the solid-liquid separation is performed exceeds the boiling point of the organic polar solvent at normal pressure, the solid-liquid separation operation must be performed under closed conditions, and a special device is required. Therefore, it is not preferable from the viewpoint of simplicity of operation and economy. Here, the normal pressure is a pressure near the standard state of the atmosphere, and is a temperature near about 25 ° C. and an atmospheric pressure condition near 101 kPa in absolute pressure.

Here, as the filter, a container used in a method using a filter such as a sieve, a method using a centrifugal filter, a method using a vibration screen, a method using a pressure filter, a method using a suction filter, etc. However, it is not limited to these.

The atmosphere for solid-liquid separation is not particularly limited, but if the cyclic PAS or organic polar solvent is oxidatively deteriorated due to conditions such as the time and temperature of contact, perform it in a non-oxidizing atmosphere. Is preferable.

<(3) Removal of organic polar solvent>
The preferred embodiment of the method for recovering the cake (c) from the filtrate (B) solid-liquid separated from the reaction mixture (A) will be described in detail below.

The method of removing the organic polar solvent from the filtrate (B) and recovering the cake is not particularly limited, and the filtrate (B) is brought into contact with a solvent having low solubility in the PAS component and mixed with the organic polar solvent to form a cyclic formula. A method of precipitating and recovering PAS, after removing a part or most of the organic polar solvent of the filtrate (B) by an operation such as distillation, contact with a solvent having low solubility in the PAS component and mixing with the organic polar solvent. A method for recovering the cake (c) containing the PAS particles (a) containing the cyclic PAS as a main component, the filtrate (B) is cooled to precipitate the cyclic PAS, and the precipitated cyclic PAS is recovered. Examples thereof include a method in which the filtrate (B) is heated below normal pressure to remove an organic polar solvent, and a cake (c) containing PAS particles (a) containing cyclic PAS as a main component is recovered. Among them, after removing a part or most of the organic polar solvent by an operation such as distillation, the cyclic PAS is the main component by contacting with a solvent having low solubility in the PAS component and miscible with the organic polar solvent. A method of recovering the cake (c) containing the PAS particles (a) is preferable. Further, the solvent having such characteristics is generally a solvent having a relatively high polarity, and the preferable solvent differs depending on the type of the organic polar solvent used, so that the solvent cannot be limited, but for example, water, methanol, ethanol, propanol, isopropanol, butanol. , Alcohols typified by hexanol, acetone, ketones typified by methyl ethyl ketone, and acetate esters typified by ethyl acetate and butyl acetate can be exemplified, and water, methanol and acetone are preferable from the viewpoint of availability and economy. , Water is particularly preferred. By performing the treatment with such a solvent, it is possible to reduce the amount of the organic polar solvent and the by-product salt contained in the cake (c). Since the cyclic PAS is precipitated as a solid component by this treatment, the cake (c) can be recovered by using a known solid-liquid separation method. Specific examples include separation by filtration, centrifugation, decantation, and the like. In this way, the cake (c) can be obtained.

[Washing of polyarylene sulfide particles]
In the present invention, it is possible to obtain high-purity PAS particles with reduced impurities by using the cleaning method described below for the cake (c) obtained by the above-mentioned method or the like.

In the present invention, the cake (c) is arranged on a filter on which a filter medium is installed so that the density is 800 kg / m ³ or more, and the filtrate (d) is discharged from the lower part of the filter by filtration, and at the same time, the cleaning liquid (d) It is characterized in that the PAS particles (a) are washed by supplying e). In order to perform more efficient cleaning, the cake density is preferably high, 900 kg / m ³ or more is more preferable, and 1000 kg / m ³ or more is further preferable. Further, the upper limit of the density cannot be unconditionally defined because it depends on the type of the target PAS and the type of the liquid (b), but is generally higher than the density of the PAS alone and the liquid content of the cake (c). It can be exemplified as 1300 kg / m ³ or less.

In the present invention, the filtrate (d) is a liquid (b) or a composite liquid of the liquid (b) and the cleaning liquid (e). In a cake having a density higher than a certain level as in the present invention, it can be inferred that the liquid (b) is present in the gaps filled with the PAS particles (a). By pouring the cleaning liquid (e) into the cake from the side opposite to the filter medium, the cleaning liquid (e) replaces the cake (c) with the liquid (b) in a one-to-one quantitative relationship (hereinafter referred to as extrusion replacement). It may be called.) At this time, the impurities contained in the liquid (b) are also extruded and replaced at the same time, so that the impurities can be washed more efficiently. Further, the density can be calculated by measuring the volume of the cake cut into an area of 1/100 or more of the effective filtration area and dividing the weight at that time by the volume value. When the area of the cake is huge, such as in continuous production, it is more accurate to obtain it as the average value of 10 randomly sampled samples.

In the present invention, the relationship between the supply rate of the cleaning liquid (e) and the discharge rate of the filtrate (d) is not limited, but the following formula 1 must be satisfied in order to perform cleaning with high efficiency by extrusion replacement. desirable.
ΔV = | V ₁ −V ₂ | / V ₁ ≦ 0.2 ・ ・ ・ Equation 1
(The discharge rate of the filtrate (d) is defined as V ₁ [kg / (sec · m ² )], and the supply rate of the cleaning solution (e) is defined as V ₂ [kg / (sec · m ² )].)

Since the liquid (b) is extruded and replaced with the cleaning liquid (e), the liquid (b) must not be diluted by the cleaning liquid (e), and V ₂ must not greatly exceed V ₁ . Further, if the amount of the cleaning liquid (e) is small, air may enter the cake and the compacted cake may be cracked. Since the cleaning liquid (e) preferentially flows out from this crack, it is necessary not to make V ₂ significantly lower than V ₁ so that the cake cannot be cracked. Further, ΔV ≦ 0.15 is more preferable, ΔV ≦ 0.10 is further preferable, and ΔV ≦ 0.05 is particularly preferable. These speeds can be obtained processally from the speeds measured by the flow meters of the filtrate (d) and the cleaning liquid (e) and the effective filtration area of the filter used.

Further, the filtrate discharge rate V ₁ and the cleaning liquid supply speed V ₂ differ depending on the liquid (b) and the cleaning liquid (e), but are not particularly limited as long as the essence of the present invention is not impaired, and are 0.01 to 0.50. The range of [kg / (sec · m ² )] can be exemplified. At a speed within this range, it is considered that ΔV can be easily controlled and the cleaning efficiency by extrusion replacement becomes relatively high. It should be noted that this example is an example and does not limit the speed in the present invention.

The thickness of the cake (c) is not particularly limited, but a range of 2 mm or more and 50 mm or less can be exemplified. As the upper limit of the cake thickness, a thickness that facilitates the flow of the cleaning liquid (e) is desirable, preferably 30 mm or less, more preferably 20 mm or less, still more preferably 15 mm or less. Further, in order to prevent the above-mentioned cracking from occurring, the lower limit of the cake thickness is preferably 2 mm or more.

The amount of the cleaning liquid (e) used in the present invention is not particularly limited as long as it does not impair the essence of the present invention, but the upper limit may be, for example, 10 times or less the amount of the liquid (b). The amount may be doubled or less, 6 times or less, tripled or less, or equal or less. This is because the present invention is characterized by cleaning by extrusion replacement of the liquid (b) with the cleaning liquid (e), so that even a small amount of the cleaning liquid (e) as described above can exhibit high cleaning efficiency. is there. In particular, the fact that the liquid (b) originally present in the cake (c) can be removed by extrusion replacement even if the amount of the cleaning liquid is equal to the liquid (b) originally present in the cake (c). , A feature of the present invention that cannot be reached by other cleaning methods. Further, as the lower limit, from the viewpoint of removing the liquid (b) by extrusion substitution, the amount of the liquid (b) is preferably 0.5 times or more, more preferably the same size or more.

The replacement rate of the liquid (b) originally present in the cake (c) and the cleaning liquid (e) is the weight of the liquid (b) originally present in the cake (c) M ₁ [g]. The residual weight of the liquid (b) contained in the cake (c) after washing is M ₂ [g], and is shown as follows.
Substitution rate = (M _1- M ₂ ) / M ₁ ... Equation 2

In the present invention, the substitution rate is preferably 70% or more, more preferably 85% or more, even more preferably 95% or more, and even more preferably 100%. The upper limit is 100% or less. This is because there are many impurities present in the liquid (b), and the substitution rate of the liquid (b) greatly affects the cleaning efficiency. As a method for measuring the substitution rate, when the cleaning liquid (e) and the liquid (b) are different, a gas chromatograph (hereinafter, may be abbreviated as GC) or a high performance liquid chromatograph (hereinafter, may be abbreviated as HPLC). ), And calculate by the ratio of the peak derived from the component of the liquid (b) or the peak derived from the component dissolved and contained only in the liquid (b) before and after washing. Can be done.

As the cleaning liquid (e) used in the present invention, at least one selected from water and an organic solvent is used. The type of cleaning liquid varies depending on the type of target PAS particles (a) and liquid (b) and impurities to be removed, but PAS does not substantially cause unfavorable side reactions such as dissolution or decomposition and cross-linking reaction. Is preferable. For example, as the cleaning liquid (e) preferable for removing inorganic impurities, alcohols such as water, methanol, ethanol, propanol, butanol, pentanol, ethylene glycol, and propylene glycol are preferable, and water is particularly preferable. Also, if necessary, formic acid, acetic acid, propionic acid, butyric acid, chloroacetic acid, dichloroacetic acid, acrylic acid, benzoic acid, salicylic acid, oxalic acid, malonic acid, succinic acid. Organic acidic compounds such as phthalic acid and fumaric acid and inorganic acidic compounds such as alkali metal salts, alkaline earth metal salts, sulfuric acid, phosphoric acid, hydrochloric acid, carbonic acid and silicic acid may be added and used.

As the cleaning solution (e) preferable for removing organic impurities, since the organic impurities are often dissolved in the liquid (b), a cleaning solution having a solubility and polarity close to that of the liquid (b) is desirable. For example, alcohol-phenolic solvents such as methanol, ethanol, propanol, butanol, pentanol, ethylene glycol, propylene glycol, phenol, cresol, polyethylene glycol, N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, N. N-alkylpyrrolidones such as −cyclohexyl-2-pyrrolidone, halogen-based solvents such as chloroform, bromoform, methylene chloride, 1,2-dichloroethane, 1,1,1-trichloroethane, chlorobenzene, 2,6-dichlorotoluene, pentane , Hexane, heptane, octane, cyclohexane, cyclopentane, benzene, toluene, xylene and other hydrocarbon solvents, acetone, methyl ethyl ketone, diethyl ketone, methyl isobutyl ketone, methyl butyl ketone, acetphenone and other ketone solvents, methyl acetate, acetate. Examples thereof include carboxylic acid ester-based solvents such as ethyl, pentyl acetate, octyl acetate, methyl butyrate, ethyl butyrate, pentyl butyrate, methyl salicylate, ethyl formate, and water, and among them, methanol, ethanol, propanol, butanol, pentanol, and ethylene. Organic solvents such as glycol, propylene glycol, chloroform, methylene chloride, 1,2-dichloroethane, pentane, hexane, heptane, octane, cyclohexane, cyclopentane, acetone, methyl acetate and ethyl acetate are preferred, with methanol, ethanol, propanol and ethylene. Glycol, chloroform, methylene chloride, 1,2-dichloroethane, acetone, ethyl acetate and NMP are particularly preferred, and methanol, acetone and NMP are even more preferred.

With respect to the cleaning liquids listed above, it is possible to use two or more kinds as a composite liquid, and in this case, it is desirable that they are in a mixed state. Alternatively, it is also possible to wash by continuously using two or more kinds of the above-mentioned cleaning liquids, and the order, the number of times, and the amount of the liquids are not limited as long as the essence of the present invention is not impaired. In order to extrude and replace the liquid (b), the lower limit of the liquid amount is preferably 0.5 times or more the total amount of the cleaning liquid, and more preferably the same size or more. Further, the upper limit may be 10 times or less of the liquid (b), 9 times or less, or 6 times or less. When two or more types of cleaning liquids are used in order, a higher cleaning effect can be exhibited even if the total amount of the two or more types of cleaning liquids is less than or equal to the cleaning liquid amount for cleaning with a single cleaning liquid. In addition, it is also possible to obtain a combined cleaning effect of each cleaning solution used in two or more types. The ratio of the two or more types of cleaning liquid amounts is not particularly limited as long as it is within the above-mentioned liquid amount range, but cleaning can be performed by changing the ratio according to the impurities to be cleaned. For example, when it is desired to particularly clean inorganic impurities, a large amount of a cleaning solution preferable for removing the above-mentioned inorganic impurities can be used, and when it is particularly desired to clean organic impurities, a large amount of a cleaning solution preferable for removing organic impurities can be used. When it is desired to remove organic impurities together, cleaning can be performed with each cleaning liquid amount according to the ratio of the impurity amount.

The cleaning atmosphere and temperature also differ depending on the cleaning liquid (e) used for the target PAS, but when the PAS component and the cleaning liquid are oxidatively deteriorated due to temperature conditions, it is desirable to perform the cleaning in a non-oxidizing atmosphere. The cleaning temperature is not particularly limited, but it is desirable that the upper limit temperature is equal to or lower than the recirculation temperature of the cleaning liquid (e) used under atmospheric pressure, and the temperature at which the target PAS particles (a) can maintain the particle shape. Is desirable. For example, when it is desired to obtain PAS particles (a) containing cyclic PAS as a main component with high purity, when the above-mentioned preferable cleaning solution (e) is used, the temperature is preferably 20 to 150 ° C, more preferably 30 to 100 ° C. It can be exemplified as a preferable specific temperature range.

With respect to the filter medium used in the present invention, although it depends on the particle size of the obtained PAS particles (a), a cake (c) containing at least the PAS particles (a) can be formed on the filter medium, and the liquid (b) can pass through. There are no particular restrictions as long as it can be done. Therefore, the filter medium used in the present invention may be a filter medium that is stable under the conditions for solid-liquid separation, and a commonly used filter medium such as a membrane filter, a glass filter, or a wire mesh or a filter cloth can be exemplified, and a glass filter that can be used repeatedly. Wire mesh and cloth are preferable, and wire mesh and cloth are particularly preferable. Further, it is preferable that any of the filter media is commercially available from the viewpoint of availability.

The material of the wire mesh used in the present invention cannot be unconditionally specified because it depends on the solid-liquid separation conditions such as temperature and the component composition of the reaction mixture (A) such as an organic polar solvent, but the conditions for solid-liquid separation as described above. As long as it is stable, there is no particular limitation. Examples of the material of the wire mesh preferably used in the present invention include stainless steel such as SUS304, SUS316, and SUS316L, and special steel such as Hastelloy. Among them, the above-mentioned stainless steel generally used from the viewpoint of versatility is preferable, and SUS316 or SUS316L is more preferable.

Similarly, the material of the cloth used in the present invention cannot be unconditionally specified because it depends on the solid-liquid separation conditions such as temperature and the component composition of the reaction mixture (A) such as an organic polar solvent. It is not particularly limited as long as it is stable under the conditions to be performed. Examples of the material of the cloth preferably used in the present invention include polypropylene, polyethylene terephthalate, and nylon, which are generally used, polyphenylene sulfide having higher heat resistance and chemical resistance, and polytetrafluoroethylene. it can. Of these, polypropylene, polyethylene terephthalate, and nylon, which are generally used, are preferable from the viewpoint of filter media cost, and polypropylene is more preferable. Further, since the solid-liquid separability generally does not depend on the material of the filter cloth, the material can be selected according to the temperature of the solid-liquid separation and the type of the organic polar solvent used. For example, when it is difficult to apply the polypropylene from the viewpoint of heat resistance and chemical resistance, polyphenylene sulfide and polytetrafluoroethylene, which have higher heat resistance and chemical resistance, can be preferably selected.

Here, as a preferable upper limit of the pore diameter or the opening of the filter medium used in the present invention, 70 μm or less can be exemplified, more preferably 60 μm or less, still more preferably 50 μm or less. Further, as the lower limit, 10 μm or more can be exemplified, 15 μm or more is preferable, and 20 μm or more is particularly preferable.

Here, in general, the size of the mesh opening of the wire mesh is often indicated by "mesh", and 350 mesh or more can be exemplified as a preferable lower limit, 400 mesh or more is more preferable, and 500 mesh or more is further preferable. Further, as a preferable upper limit, 2000 mesh or less can be exemplified, 1000 mesh or less is more preferable, and 800 mesh or less is further preferable. Although the numerical value of "mesh" differs slightly depending on the manufacturer, the above-mentioned preferable mesh size range is included in the above-mentioned preferable opening range.

In addition, since the pore diameter or opening of the cloth is generally difficult to express as a numerical value due to its complicated shape and size, it is indicated by "breathability (cm ³ / (cm ² seconds))" instead. .. Therefore, the size of the holes in the cloth used in the present invention is also indicated by breathability, but the preferable upper limit of breathability is 50 cm ³ / (cm ² · sec) or less, and 30 cm ³ / (cm ² · sec) or less is more preferable. Preferably, it is 20 cm ³ / (cm ² · sec) or less, more preferably 10 cm ³ / (cm ² · sec) or less. Further, as the lower limit, 1 cm ³ / (cm ² · sec) or more can be exemplified, 2 cm ³ / (cm ² · sec) or more is more preferable, and 3 cm ³ / (cm ² · sec) or more is further preferable. The air permeability of the present invention is a value measured by the method specified in JIS L 1096.

By using a filter medium having a pore diameter or opening in the above range, or a cloth having an air permeability in the above range, it becomes easier to form a cake on the filter medium, and the smaller the pore diameter or the air permeability, the easier the cake formation. It tends to be. On the other hand, if the pore diameter or the opening of the filter medium is made too small, clogging tends to occur, and the separation efficiency tends to decrease when the same filter medium is used repeatedly. Further, in general, the filter medium tends to be more expensive as the pore diameter or opening and the smaller the air permeability, but if it is within the above range, it can be used industrially without any problem.

[Recovered polyarylene sulfide]
The PAS particles obtained by the present invention or the obtained molten polymer obtained by melt-polymerizing the obtained PAS particles (a) containing cyclic PAS as a main component to increase the molecular weight (hereinafter, these are combined and obtained in the present invention). In order for PAS) to exhibit excellent characteristics as PAS, the ash content is preferably 0.25% by weight or less, more preferably 0.15% by weight or less, and 0.10% by weight. The following is more preferable, and 0.05% by weight or less is particularly preferable. Similarly, the amount of generated gas is preferably 800 ppm or less, more preferably 600 ppm or less, further preferably 500 ppm or less, and even more preferably 400 ppm or less.

The PAS particles obtained by the present invention showing the ash content and the amount of generated gas contain less impurities, and therefore have heat resistance, chemical resistance, flame retardancy, electrical properties, and mechanical properties as compared with conventional PAS. It is excellent, and since the amount of gas generated in the molten state is small, it has good moldability in injection molding, injection compression molding, blow molding, and extrusion molding, and it is possible to reduce the manufacturing cost with less contamination of the molding machine. In addition, high quality can be expected because the characteristics of sheets, films, fibers, pipes, etc. are less likely to deteriorate due to gas when used at high temperatures.

Further, the applications of PAS obtained in the present invention include, for example, sensors, LED lamps, connectors, sockets, resistors, relay cases, switches, coil bobbins, condensers, variable condenser cases, optical pickups, oscillators, various terminal boards, metamorphic devices, etc. Electrical / electronic parts / VTR parts such as plugs, printed boards, tuners, speakers, microphones, headphones, small motors, magnetic head bases, power modules, semiconductors, liquid crystal, motor brush holders, parabolic antennas, computer-related parts, etc. For TV parts, irons, hair dryers, rice cooker parts, microwave parts, acoustic parts, audio equipment parts such as audio / laser discs (registered trademarks) / compact discs, lighting parts, refrigerator parts, air conditioner parts, typewriter parts, etc. Typical household, office electrical product parts / office computer related parts, telephone equipment related parts, facsimile related parts, copying machine related parts, cleaning jigs, motor parts, lighters, etc. Machine related parts / microscopes, Optical equipment such as binoculars, cameras, watches, precision machinery related parts / water faucet pieces, mixing faucets, pump parts, pipe joints, water volume control valves, relief valves, hot water temperature sensors, water volume sensors, water meter housings, etc. Water parts / valves Alternate terminal, alternator connector, IC regulator, exhaust gas valve and other valves, fuel-related / exhaust / intake system pipes, air intake nozzle snorkel, intake manifold, fuel pump, engine cooling water joint, carburetor Main body, carburetor spacer, exhaust gas sensor, cooling water sensor, oil temperature sensor, throttle position sensor, crank shaft position sensor, air flow meter, brake pad wear sensor, thermostat base for air conditioner, heating hot air flow control valve, radiator motor Brush holder, water pump impeller, turbine vane, wiper motor related parts, dustributor, starter switch, starter relay, wire harness for transmission, window washer nozzle, air conditioner panel switch board, fuel related electromagnetic valve coil, fuse connector , Horn terminal, Electrical component insulation plate, Step motor rotor, Lamp socket, Lamp reflector, lamp housing, brake piston, solenoid bobbin, engine oil filter, ignition device case, vehicle speed sensor, cable liner, engine control unit case, engine driver unit case, condenser case, motor insulation material, hybrid car control system parts case Examples include automobile / vehicle-related parts such as, and various other uses.

As a method for producing a PAS film using PAS obtained in the present invention, a known melt film forming method can be adopted. For example, after melting PAS in a single-screw or twin-screw extruder, a film die is used. Manufactured by a method of producing a film by cooling on an extrusion cooling drum, or a biaxial stretching method in which the film produced in this way is stretched vertically and horizontally by a roller-type longitudinal stretching device and a transverse stretching device called a tenter. However, it is not particularly limited to this.

The PAS film thus obtained in the present invention has excellent mechanical properties, electrical properties, and heat resistance, and is used in various applications such as dielectric film applications for film capacitors and chip capacitors, and release film applications. It can be preferably used.

As a method for producing PAS fibers using PAS obtained in the present invention, a known melt spinning method can be applied. For example, a PAS chip as a raw material is kneaded while being supplied to a single-screw or twin-screw extruder. Then, a method of extruding from the spinneret via a polymer streamline changer installed at the tip of the extruder, a filtration layer, etc., and performing cooling, stretching, and heat setting can be adopted, but is particularly limited to this. It's not something.

The PAS monofilaments or short fibers thus obtained in the present invention can be suitably used for various applications such as papermaking dryer campuses, net conveyors, and bag filters.

The present invention will be specifically described below with reference to examples. These examples are exemplary and not limiting.

<Vacuum drying of cake>
The cake was dried under the following conditions.
Equipment: Yamato Chemical Square Vacuum Dryer ADP300
Conditions: 130 ° C, 12 hours (vacuum conditions)

<Measurement of liquid (b) substitution rate>
The substitution rate of the liquid (b) was determined using a gas chromatograph.

About 0.5 g of unwashed and washed cake was dissolved in about 6 g of chloroform, filtered using a membrane filter having a pore size of 0.45 μm, and the obtained solution was subjected to GC measurement. The substitution rate was calculated from the degree of decrease in the peak value derived from the measured NMP. The measurement conditions of GC are shown below.
Equipment: Shimadzu GC-2010
Column: J & W DB-5 inner diameter 0.32 mm, length 30 m (film thickness 0.25 μm)
Carrier gas: Helium detector: Hydrogen flame ionization detector (FID)

<Melting polymerization of PPS particles containing cyclic PPS as the main component>
The melt polymerization of the cyclic PPS was carried out by the following method.

1.5 g of cyclic PPS was charged into a test tube, the inside of the test tube was replaced with nitrogen, and then the pressure was reduced using a vacuum pump to obtain vacuum conditions (2 Torr or less). While maintaining the pressure in the test tube, it was inserted into an electric tube furnace heated to 340 ° C. and heated for 6 hours. After heating, the test tube was taken out and cooled to room temperature to obtain a high molecular weight PPS solid.
Equipment: Asahi Rika ARF-30KC Ceramic Electric Tube Furnace ULVAC GLD-051 Vacuum Pump Conditions: 340 ° C, 6 hours (vacuum conditions)

<Analysis of cyclic polyphenylene sulfide>
The amount of cyclic PPS contained in the PPS particles was determined by HPLC.

About 10 mg of PPS was dissolved in about 5 g of 1-chloronaphthalene at 250 ° C., cooled to room temperature, and filtered using a membrane filter having a pore size of 0.45 μm to obtain a 1-chloronaphthalene-soluble component. The obtained soluble component was analyzed by HPLC and the amount of cyclic PPS was quantified.

The amount of cyclic PPS in the cake was also determined by HPLC in the same manner.

About 10 mg of a dry solid of cake was dissolved in about 10 g of chloroform, stirred well, filtered using a membrane filter having a pore size of 0.45 μm, and the obtained soluble component was analyzed by HPLC to quantify the amount of cyclic PPS. The HPLC measurement conditions are shown below.
Equipment: Shimadzu LC-10Avp Series Column: Kanto Chemical Co., Ltd. Mightysil RP-18GP
Length 150 mm, inner diameter 4.6, (film thickness 5 μm)
Detector: Photodiode array detector (wavelength 270 nm)

<Molecular weight measurement>
The molecular weight of PPS was calculated in terms of polystyrene using a gel permeation chromatograph (hereinafter, may be abbreviated as GPC), which is a type of size exclusion chromatograph. The measurement conditions of GPC are shown below.
Equipment: Senshu Kagaku SSC-7110
Column: Showa Denko Shodex UT-G + Shodex UT-806M x 2
Eluent: 1-chloronaphthalene detector: differential refractive index detector Column temperature: 210 ° C
Pre-constant temperature bath temperature: 250 ° C
Pump constant temperature bath temperature: 50 ° C
Detector temperature: 210 ° C
Flow rate: 1.0 mL / min
Sample injection volume: 300 μL (concentration: 0.1% by weight)
Standard sample: polystyrene

<Measurement of ash content>
The ash content was measured under the following conditions.

Approximately 5 g of the dry solid of the cake was heated in an electric furnace at 550 ° C. for 6 hours, and then cooled to determine the weight of the recovered ash. The conditions are shown below.
Equipment: Thomas Kagaku Kikai Co., Ltd. TMF-5
Conditions: 550 ° C, 6 hours

<Measurement of generated gas amount>
The amount of gas generated when melted was determined by the following method.

1 g of PPS was placed in a glass ampoule and vacuum-sealed. Only the body of this glass ampoule was inserted into an electric tube furnace and heated. After taking out the ampoule, the neck of the ampoule, which was not heated by the electric tube furnace and had volatile gas aggregated and adhered, was cut out with a file, and the weight and the weight after removing the deposit were measured, and the amount of gas generated was calculated. The equipment and utensils used are shown below.
Equipment: Asahi Rika ARF-30KC Ceramic Electric Tube Furnace Glass Ampoule: Body 100 mm x 25 mmφ, neck 255 mm x 12 mmφ, wall thickness 1 mm
Conditions: 320 ° C, 2 hours (vacuum sealed state)

[Reference example 1]
Here, an example of collecting the cake (c) is shown.

<Preparation of reaction mixture>
23.36 g (11.21 g (0.200 mol) of sodium hydrosulfide) and 17.50 g (water) of a 48 wt% aqueous solution of sodium hydroxide in a 1 liter autoclave equipped with a stirrer. 8.40 g (0.210 mol) of sodium oxide), 500 mL of N-methyl-2-pyrrolidone (NMP), and 30.00 g (0.200 mol) of p-dichlorobenzene (p-DCB) were charged. The reaction vessel was sealed under nitrogen gas at room temperature and normal pressure, and then the temperature was raised from room temperature to 200 ° C. over 25 minutes while stirring at 400 rpm. Then, the temperature was raised to 245 ° C. over 25 minutes. After holding at 245 ° C. for 6 hours, the mixture was rapidly cooled to near room temperature to obtain a reaction mixture.

<Solid-liquid separation>
150.0 g of the above reaction mixture was separated, charged into a 300 mL flask, and replaced with nitrogen. The reaction mixture was kept at 90 ° C. for 30 minutes in a constant temperature bath with stirring using a magnetic stirrer.

A membrane filter (made of PTFE) with a diameter of 90 mm and a pore diameter of 10 μm is installed in the filter holder KST-90-UH (effective filtration area of about 45.3 cm ² ) manufactured by ADVANTEC with a universal tank, and the tank part is a band heater. The temperature was adjusted to 35 ° C.

The entire amount of the reaction mixture heated to 90 ° C. was charged into the tank, the tank was sealed, the inside of the tank was pressurized to 0.1 MPa with nitrogen, and about 124 g of the filtrate was recovered.

<Removal of organic polar solvent>
90 g of the above filtrate was placed in a 300 mL flask, and the inside of the flask was replaced with nitrogen. Then, the mixture was heated to 100 ° C. with stirring, and 30 g of water was slowly added dropwise over about 15 minutes using a tube pump. Here, the weight ratio of NMP to water in the filtrate mixture after the completion of dropping water was 75:25. When water was added to this filtrate, solids were gradually formed in the mixture, and when the dropping of water was completed, the solids were dispersed into a slurry. The slurry is cooled to about 30 ° C. over about 1 hour with stirring, and then stirring is continued at 30 ° C. or lower for about 30 minutes, and then the obtained slurry is suction-filtered with a glass filter having a pore diameter of 10 to 16 μm. Got a cake.

<Vacuum drying of cake>
The cake was vacuum dried at 130 ° C. for 12 hours to obtain a solid content in the cake as a dry solid. From this drying process, the cake was found to contain 64% by weight of liquid. Moreover, as a result of analyzing the obtained dry solid by the KBr method of IR measurement, it was found that 99% or more of the solid content of the cake was PPS.

<Analysis of cyclic polyphenylene sulfide>
As a result of analyzing the above dry solid by HPLC, it was found that the solid content of the cake contained 89% of cyclic PPS.

<Measurement of ash content>
As a result of ashing the dry solid in an electric furnace at 550 ° C. for about 6 hours, the ash content of the cake was 0.35% by weight, and the cake contained an inorganic substance that was the source of this ash. all right.

<Melting polymerization of PPS particles containing cyclic PPS as the main component>
A dark brown solid was obtained by heating 1.5 g of the above dry solid at 340 ° C. for 6 hours under vacuum conditions.

<Molecular weight measurement>
As a result of GPC analysis of the dark brown solid obtained by melt polymerization, it was found that the weight average molecular weight was 64,000.

<Measurement of generated gas amount>
As a result of measuring the amount of gas generated when 1 g of the dark brown solid was heated at 320 ° C. for 2 hours, it was found that the amount of gas was 810 ppm.

[Example 1]
Here, an example of recovering high-purity PPS particles in which inorganic and organic impurities are efficiently reduced by cleaning with controlled cake density is shown.

A cake with an inner diameter of 38 mm sandwiched between a membrane filter having a pore diameter of 10 μm is filled with 8.4 g of the cake described in Reference Example 1 at a density of about 930 kg / m ³ (hereinafter, the density is a cake in an area of 100% effective filtration area). It was calculated from the volume and weight of.), And was filled by applying pressure from above so that the cake thickness was about 8 mm. At this time, the amount of liquid (NMP: water = 3: 1) in the cake was 5.5 g. This was suction-filtered using an aspirator under room temperature conditions, and 5.5 g of water (equal to the weight of the liquid in the cake) was supplied onto the cake for washing. At this time, the filtrate discharge rate was about 0.13 kg / (sec m ² ), and the supply rate of water as a cleaning liquid was 0.44 kg / (sec m ² ). As a result of GC analysis of the solid content after washing and calculating the replacement rate of the liquid (b) in the cake, the replacement rate was 78%.

Further, the obtained solid content was treated in a vacuum dryer at 130 ° C. for 12 hours to obtain a dry solid of PPS particles. This dry solid was incinerated in an electric furnace at 550 ° C. for 6 hours, and the amount of ash after washing was measured. As a result, it was found that high-purity PPS particles having an ash content of 0.24% by weight were obtained.

[Example 2]
Here, an example of recovering high-purity PPS particles in which impurities are efficiently reduced by performing the same operation as in Example 1 except that the amount of cleaning liquid is increased is shown.

In the same manner as in Example 1, pressure was applied from above to a Kiriyama separate having an inner diameter of 38 mm sandwiching a membrane filter having a pore diameter of 10 μm so that 8.6 g of cake had a density of about 850 kg / m ³ and a cake thickness of about 9 mm. It was filled over. At this time, the amount of liquid (NMP: water = 3: 1) in the cake was 5.6 g. This was suction-filtered using an aspirator under room temperature conditions, and 16.8 g of water (three times the weight of the liquid in the cake) was supplied onto the cake for washing. At this time, the filtrate discharge rate was about 0.13 kg / (sec m ² ), and the water supply rate was 0.44 kg / (sec m ² ). As a result of GC analysis of the solid content after washing and calculating the replacement rate of the liquid (b) in the original cake, the replacement rate was 95%.

Further, the obtained solid content was treated in a vacuum dryer at 130 ° C. for 12 hours to obtain a dry solid of PPS particles. This dry solid was incinerated in an electric furnace at 550 ° C. for 6 hours, and the amount of ash after washing was measured. As a result, it was found that high-purity PPS particles having an ash content of 0.09% by weight were obtained.

[Example 3]
Here, from Example 1, an example of recovering high-purity PPS particles in which impurities are further reduced by cleaning in which the method of supplying the cleaning liquid is further adjusted is shown.

A pressure is applied from above to a Kiriyama separate having an inner diameter of 38 mm sandwiching a membrane filter having a pore diameter of 10 μm so that 8.4 g of the cake described in Reference Example 1 has a density of about 930 kg / m ³ and a cake thickness of about 8 mm. And filled. At this time, the amount of liquid (NMP: water = 3: 1) in the cake was 5.5 g. This was suction-filtered using an aspirator under room temperature conditions, and 5.5 g of water (equal to the weight of the liquid in the cake) was supplied from above the cake at a controlled speed to perform washing. At this time, the filtrate discharge rate was about 0.13 kg / (sec m ² ), and the controlled water supply rate was also about 0.13 kg / (sec m ² ). The obtained solid content was vacuum dried at 130 ° C. for 12 hours to obtain a dry solid of PPS particles.

This dry solid was incinerated in an electric furnace at 550 ° C. for 6 hours, and the amount of ash after washing was measured. As a result, it was found that high-purity PPS particles having an ash content of 0.20% by weight were obtained.

[Example 4]
Here, an example of recovering high-purity PPS particles by washing with a larger amount of washing liquid than in Example 3 is shown.

A membrane filter having a pore diameter of 10 μm and an inner diameter of 38 mm was filled with 9.2 g of cake by applying pressure from above so as to have a density of about 1010 kg / m ³ and a cake thickness of about 8 mm. At this time, the amount of liquid (NMP: water = 3: 1) in the cake was 6.1 g. This was suction-filtered using an aspirator under room temperature conditions, and 18.2 g of water (three times the weight of the liquid in the cake) was supplied onto the cake at a controlled speed to perform washing. At this time, the filtrate discharge rate was about 0.13 kg / (sec m ² ), and the water supply rate was about 0.13 kg / (sec m ² ). As a result of GC analysis of the solid content after washing and calculating the replacement rate of the liquid (b) in the original cake, the replacement rate was 98%.

Further, the obtained solid content was vacuum dried at 130 ° C. for 12 hours to obtain a dry solid of PPS particles. This dry solid was incinerated in an electric furnace at 550 ° C. for 6 hours, and the amount of ash after washing was measured. As a result, it was found that high-purity PPS particles having an ash content of 0.07% by weight were obtained.

[Example 5]
Here, an example of recovering high-purity PPS particles by washing with a larger amount of cleaning liquid than in Example 4 is shown.

A membrane filter having a pore diameter of 10 μm and an inner diameter of 38 mm was filled with 8.6 g of cake under pressure from above so as to have a density of about 940 kg / m ³ and a cake thickness of about 8 mm. At this time, the amount of liquid (NMP: water = 3: 1) in the cake was 5.5 g. This was suction-filtered using an aspirator under room temperature conditions, and 33.2 g of water (6 times the weight of the liquid in the cake) was supplied onto the cake at a controlled speed to perform washing. At this time, the filtrate discharge rate was about 0.13 kg / (sec m ² ), and the water supply rate was about 0.13 kg / (sec m ² ). As a result of GC analysis of the solid content after washing and calculating the replacement rate of the liquid (b) in the original cake, the replacement rate was 99%.

Further, the obtained solid content was vacuum dried at 130 ° C. for 12 hours to obtain a dry solid of PPS particles. This dry solid was incinerated in an electric furnace at 550 ° C. for 6 hours, and the amount of ash after washing was measured. As a result, it was found that high-purity PPS particles having an ash content of 0.03% by weight were obtained.

A brown solid was obtained by heating 1.5 g of the above dry solid at 340 ° C. for 6 hours under vacuum conditions. As a result of GPC analysis, it was found that the weight average molecular weight was 59,000. Further, as a result of measuring the amount of gas generated when 1 g of this brown solid was heated at 320 ° C. for 2 hours, it was found that the amount of gas was 550 ppm.

[Example 6]
Here, an example of recovering high-purity PPS particles obtained by performing the same operation as in Example 5 except that a composite solution having a ratio of NMP to water of 3: 1 (hereinafter referred to as a mixed solution) is used as the cleaning solution is shown.

In the same manner as in Example 5, pressure was applied from above to a Kiriyama separate having an inner diameter of 38 mm sandwiching a membrane filter having a pore diameter of 10 μm so that 8.6 g of cake had a density of about 950 kg / m ³ and a cake thickness of about 8 mm. It was filled over. At this time, the amount of liquid (NMP: water = 3: 1) in the cake was 5.5 g. This was suction-filtered using an aspirator under room temperature conditions, and 33.3 g of a mixed solution (6 times the weight of the liquid in the cake) was supplied onto the cake at a controlled speed to perform washing. At this time, the filtrate discharge rate was about 0.03 kg / (sec m ² ), and the supply rate of the mixed solution was about 0.03 kg / (sec m ² ). The obtained solid content was vacuum dried at 130 ° C. for 12 hours to obtain a dry solid of PPS particles. This dry solid was incinerated in an electric furnace at 550 ° C. for 6 hours, and the amount of ash after washing was measured. As a result, it was found that high-purity PPS particles having an ash content of 0.14% by weight were obtained.

A brown solid was obtained by heating 1.5 g of the above dry solid at 340 ° C. for 6 hours under vacuum conditions. As a result of GPC analysis, it was found that the weight average molecular weight was 71,000. Further, as a result of measuring the amount of gas generated when 1 g of this brown solid was heated at 320 ° C. for 2 hours, it was found that the amount of gas was 410 ppm.

[Example 7]
Here, an example of recovering high-purity PPS particles by continuous cleaning with two types of cleaning liquids, in which half of the cleaning liquid amount is the same as in Examples 5 and 6 and water is used as the other half, is shown.

A Kiriyama separate having an inner diameter of 38 mm sandwiching a membrane filter having a pore diameter of 10 μm was filled with 8.6 g of cake by applying pressure from above so as to have a density of about 950 kg / m ³ and a cake thickness of about 8 mm. At this time, the amount of liquid (NMP: water = 3: 1) in the cake was 5.5 g. This is suction-filtered using an aspirator under room temperature conditions, and the speed is controlled to supply 16.6 g of a mixed solution (three times the weight of the liquid in the cake) on the cake, and then the speed is controlled. Then, 16.7 g of water (three times the weight of the liquid in the cake) was supplied for washing. When the mixed solution is supplied, the filtrate discharge rate is about 0.03 kg / (sec, m ² ), the supply rate of the mixed solution is about 0.03 kg / (sec, m ² ), and when water is subsequently supplied, the filtrate is discharged. The filtrate discharge rate was about 0.13 kg / (sec m ² ), and the water supply rate was about 0.13 kg / (sec m ² ). As a result of GC analysis of the solid content after washing and calculating the replacement rate of the liquid (b) in the original cake, the replacement rate was 99%.

Further, the obtained solid content was vacuum dried at 130 ° C. for 12 hours to obtain a dry solid of PPS particles. This dry solid was incinerated in an electric furnace at 550 ° C. for 6 hours, and the amount of ash after washing was measured. As a result, it was found that high-purity PPS particles having an ash content of 0.03% by weight were obtained.

A brown solid was obtained by heating 1.5 g of the above dry solid at 340 ° C. for 6 hours under vacuum conditions. As a result of GPC analysis, it was found that the weight average molecular weight was 59,000. Further, as a result of measuring the amount of gas generated when 1 g of this brown solid was heated at 320 ° C. for 2 hours, it was found that the amount of gas was 320 ppm.

[Example 8]
Here, an example of recovering high-purity PPS particles by cleaning in which the order of the cleaning liquids used is changed from that of Example 7 in the cleaning using two kinds of cleaning liquids in succession as in Example 7 is shown.

A membrane filter having a pore diameter of 10 μm and an inner diameter of 38 mm was filled with 8.7 g of cake by applying pressure from above so as to have a density of about 950 kg / m ³ and a cake thickness of about 8 mm. At this time, the amount of liquid (NMP: water = 3: 1) in the cake was 5.6 g. This is suction-filtered using an aspirator under room temperature conditions, and the speed is controlled to supply 16.7 g of water (three times the weight of the liquid in the cake) on the cake, and then the speed is controlled. 16.7 g of the mixed solution (three times the weight of the liquid in the cake) was supplied for washing. When water is supplied, the filtrate discharge rate is about 0.13 kg / (sec, m ² ), and the water supply rate is about 0.13 kg / (sec, m ² ). The discharge rate was about 0.03 kg / (sec m ² ), and the supply rate of the mixed solution was about 0.03 kg / (sec m ² ). The obtained solid content was vacuum dried at 130 ° C. for 12 hours to obtain a dry solid of PPS particles. This dry solid was incinerated in an electric furnace at 550 ° C. for 6 hours, and the amount of ash after washing was measured. As a result, it was found that high-purity PPS particles having an ash content of 0.02% by weight were obtained.

A brown solid was obtained by heating 1.5 g of the above dry solid at 340 ° C. for 6 hours under vacuum conditions. As a result of GPC analysis, it was found that the weight average molecular weight was 56,000. Further, as a result of measuring the amount of gas generated when 1 g of this brown solid was heated at 320 ° C. for 2 hours, it was found that the amount of gas was 340 ppm.

[Comparative Example 1]
Here, an example of recovering PPS particles by reslurry cleaning using a cleaning liquid having the same amount as the liquid weight of the cake is shown.

8.4 g of the cake of Reference Example 1 (the amount of liquid in the cake was 5.5 g) was dispersed in 5.5 g of water (the amount equal to the weight of the liquid in the cake), and an attempt was made to stir at room temperature for 5 minutes. However, the cake could not be dispersed with this amount of cleaning liquid, and stirring could not be performed. The cake containing water for the cleaning liquid was suction-filtered by a Kiriyama separate with an inner diameter of 38 mm and an aspirator sandwiching a membrane filter with a pore diameter of 10 μm, but filtration was not possible, and reslurry cleaning could not be performed with this amount of cleaning liquid. all right.

[Comparative Example 2]
Here, an example of recovering PPS particles by reslurry cleaning using a cleaning liquid having an amount three times the weight of the liquid in the cake is shown.

30.3 g of the cake of Reference Example 1 (the amount of liquid in the cake is 19.5 g) is dispersed in 58.6 g of water (three times the weight of the liquid in the cake), stirred at room temperature for 5 minutes, and then finely divided. Suction filtration was performed with a Kiriyama separate having an inner diameter of 38 mm and an aspirator sandwiching a membrane filter having a pore diameter of 10 μm. As a result of measuring the replacement rate of the liquid in the original cake using a gas chromatograph for the solid content after washing, the replacement rate was 64%.

Further, the obtained solid content was vacuum dried at 130 ° C. for 12 hours to obtain a dry solid of PPS particles. This dry solid was incinerated in an electric furnace at 550 ° C. for 6 hours, and the amount of ash after washing was measured. As a result, it was found that PPS particles having an ash content of 0.13% by weight were obtained.

[Comparative Example 3]
Here, an example of recovering PPS particles by washing with a wash without controlling the density is shown.

10.2 g of the cake of Reference Example 1 (the amount of liquid in the cake is 6.6 g) without applying pressure to the Kiryama separate with an inner diameter of 38 mm sandwiching a membrane filter with a pore diameter of 10 μm without controlling the density. Filled in. The cake density at this time was about 300 kg / m ³ , and the cake thickness was about 25 mm. This was suction-filtered using an aspirator under room temperature conditions, and 16.5 g of water (three times the liquid weight of the cake) was supplied onto the cake for washing. At this time, the filtrate discharge rate was about 0.15 kg / (sec m ² ), and the water supply rate was 0.15 kg / (sec m ² ). The obtained solid content was treated in a vacuum dryer at 130 ° C. for 12 hours to obtain a dry solid of PPS particles.

This dry solid was incinerated in an electric furnace at 550 ° C. for 6 hours, and the amount of ash after washing was measured. As a result, it was found that PPS particles having an ash content of 0.20% by weight were obtained.

Comparing Example 1 and Comparative Example 1, even if the cleaning liquids had the same amount (both equal to the liquid (b)), the inorganic impurities could be reduced in Example 1, whereas Comparative Example 1 Could not be washed. In the conventional reslurry cleaning as in Comparative Example 1, if the amount of cleaning liquid is small, the cleaning efficiency tends to be low and the cleaning itself tends to be impossible. On the other hand, it was found that the technique of the present invention exerts an excellent cleaning effect even in a small amount of liquid and can obtain high-purity PPS particles.

Further, comparing Example 2 and Comparative Example 2 in which the amount of cleaning liquid was larger than that of Example 1 and Comparative Example 1 and the amount was three times the weight of the cake liquid, the amount of ash in Example 2 was up to 0.09% by weight. While it decreased, it was found that in Comparative Example 2, it decreased only to 0.13% by weight. From these, it was found that the cleaning technique of the present invention has a cleaning effect superior to that of reslurry cleaning and can obtain PPS particles having higher purity.

Control of density, comparing Comparative Example 3 to Example 2, equivalent cleaning liquid amount (cake liquid weight of 3 volumes of.) Is even, Example 2, ash content of density 850 kg / m ³ is 0 to .09 are you reduced to wt%, only up to Comparative example 3, 0.20 wt% of density 300 kg / ^{m 3} was found that no decrease. From this, it was found that the cleaning effect was enhanced by performing cleaning at a cake density of 800 kg / m ³ or more, and higher purity PPS particles could be obtained.

Comparing Example 1 and Example 3 with respect to the cleaning liquid supply method, in Example 3 in which the amount of cleaning liquid (the same amount as the weight of the cake liquid) was controlled to ΔV <0.05, the ash content ratio was 0.20. It was found that the inorganic impurities could be removed more than the ash content of 0.24% by weight of Example 1 washed with% by weight and ΔV = about 0.7.

Further, also in Examples 2 and 4 in which three times the amount of the cleaning liquid of the liquid (b) was used, in Example 4 in which ΔV <0.05 was controlled, the ash content was 0.07% by weight, and ΔV = about 0. It was found that the inorganic impurities could be removed as compared with the ash content of 0.09% by weight of Example 2 washed in No. 7. From these, it was found that higher purity PPS particles can be obtained by controlling ΔV ≦ 0.2.

Further, comparing Examples 3, 4 and 5, it was found that the cleaning efficiency of inorganic impurities increased as the amount of cleaning liquid increased. However, as the amount of cleaning liquid used increases, the manufacturing cost also increases. Considering the efficiency of the cleaning effect with respect to the amount of cleaning liquid, it was also found that the smaller the amount of cleaning liquid, the higher the cleaning efficiency.

Regarding the types of cleaning liquids, the differences in cleaning effects were compared between Examples 5 and 6 in which the same operation was performed except that water and a mixed liquid were used, respectively. In Example 5 using water, the ash content was significantly reduced to 0.03% by weight, but the gas amount was 550 ppm. On the other hand, in Example 6 using the mixed solution, the ash content was 0.14% by weight, but the gas amount was reduced to 410 ppm. From this, it was found from the ash content of 0.35% by weight and the gas amount of 810 ppm of the unwashed Reference Example 1 that inorganic impurities can be predominantly washed in water and organic impurities can be predominantly washed in the mixed solution.

Further, in Examples 7 and 8, the cleaning liquids of water and the mixed liquid (each of which is three times the amount of the liquid (b)) are used in combination, and the total amount of the cleaning liquid is equal to that of Examples 5 and 6 (liquid (b)). The cleaning effect was confirmed by setting the amount to 6 times that of.). As a result, in Example 7 in which water was used after the mixed solution, the ash content was 0.03% by weight and the amount of gas was 320 ppm, and in Example 8 in which the mixed solution was used after water, the ash content was 0.02% by weight. , The amount of gas was as low as 340 ppm. As a result, the ash content of each type of cleaning liquid was 0.03% by weight (Example 5) and the gas amount was 410 ppm (Example 6), which were lower than those of two types (Examples 7 and 8). ) Was found to have a higher cleaning effect. From these, it was found that the cleaning effect was improved by the combined use of a plurality of cleaning liquids, and higher-purity PPS particles in which both inorganic and organic impurities were reduced could be obtained.

Claims (6)

A cake (c) containing at least polyarylene sulfide particles (a) and a liquid (b) is formed at a density of 800 kg / m ³ or more, and the filtrate (d) is fed at the same time as the cleaning liquid (e) is supplied to the cake (c). A method for producing high-purity polyarylene sulfide particles, which comprises discharging and washing the polyarylene sulfide particles (a) .
The content of the polyarylene sulfide particles (a) in the cake (c) is 25% by weight or more and 90% by weight or less.
A manufacturing method in which the amount of the cleaning liquid (e) is 0.5 times or more and 1 times or less the liquid amount of the liquid (b). The discharge rate V ₁ [kg / (sec · m ² )] of the filtrate (d) discharged from the filtration surface on which the cake (c) is installed, and the supply rate of the cleaning liquid (e) to the cake (c) are V _2. The method for producing high-purity polyarylene sulfide particles according to claim 1, wherein [kg / (sec · m ² )] satisfies the following formula 1.
ΔV = | V ₁ −V ₂ | / V ₁ ≦ 0.2 ・ ・ ・ Equation 1 The method for producing high-purity polyarylene sulfide particles according to any one of claims 1 or 2, wherein the cake (c) has a thickness of 2 mm or more and 50 mm or less. The method for producing high-purity polyarylene sulfide particles according to any one of claims 1 to 3, wherein at least one selected from water and an organic solvent is used as the cleaning liquid (e). The method for producing high-purity polyarylene sulfide particles according to any one of claims 1 to 4 , wherein the replacement rate of the liquid (b) is 70% or more and 100% or less. The content of the cyclic polyarylene sulfide in the polyarylene sulfide particles (a) is 50 wt% or more, high purity polyarylene according to any one of claims 1 to 5, characterized in that 100 wt% or less Method for producing sulfide particles.