JP2018119143A - Method for producing polyarylene sulfide - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a production method for synthesizing polyarylene sulfide having a higher molecular weight than that of polyarylene sulfide for use as the raw material.SOLUTION: A method for producing polyarylene sulfide includes adding a sulfidation agent (b) and a dihalogenated aromatic compound (c) to polyarylene sulfide (a), to heat it in organic polar solvent (d) for a reaction, thus producing the polyarylene sulfide. In the method, the amount of sulfidation agent (b) added is 0.5 mol or more and less than 5 mol relative to sulfur components 100 mol in polyarylene sulfide (a).SELECTED DRAWING: None

Description

  The present invention relates to a method for producing polyarylene sulfide. More specifically, the present invention relates to a method for producing polyarylene sulfide having a molecular weight larger than that of polyarylene sulfide used as a raw material.

  Polyarylene sulfide (hereinafter sometimes abbreviated as PAS) represented by polyphenylene sulfide (hereinafter also abbreviated as PPS) has excellent heat resistance, barrier properties, chemical resistance, electrical insulation properties, and moisture and heat resistance. It is a resin having properties suitable as an engineering plastic such as flame retardancy. Also, it can be molded into various molded parts, films, sheets, fibers, etc. by injection molding and extrusion molding, and widely used in fields requiring heat resistance and chemical resistance such as various electric / electronic parts, mechanical parts, and automotive parts. It has been.

  As a specific method for producing this PAS, a method of reacting an alkali metal sulfide such as sodium sulfide with a polyhaloaromatic compound such as p-dichlorobenzene in an organic amide solvent such as N-methyl-2-pyrrolidone is proposed. This method is widely used as an industrial production method for PAS. Further, as a method for producing a high molecular weight PAS by improving the polymerization conditions, a method using an alkali metal carboxylate or the like as a polymerization aid is disclosed (for example, see Patent Document 2).

  Furthermore, as a method for obtaining a high molecular weight PAS using PAS after the polymerization reaction as a raw material, a method of curing (curing) PAS in an oxidizing atmosphere (for example, see Patent Document 3) is disclosed. This method is a method of increasing the molecular weight by crosslinking PAS.

  On the other hand, as a method for obtaining PAS having a high molecular weight without using crosslinking by using PAS after the polymerization reaction as a raw material, PPS containing covalent chlorine and 1 equivalent of covalent chlorine contained in this PPS, A method of reacting 0.05 to 1.0 mol of alkali metal sulfide in an organic amide solvent is disclosed (see Patent Document 4).

  Another method for obtaining a high molecular weight PAS without using crosslinking by using PAS after the polymerization reaction as a raw material is at least one obtained by acting an alkali metal sulfide on PAS in a hydrous polar organic solvent. A method of polymerizing a prepolymer having an alkali thiolate group at a terminal and a dihalogenated aromatic compound in a hydrous polar organic solvent is disclosed (see Patent Document 5).

  Further, as another method for obtaining a high molecular weight PAS without using cross-linking by using PAS after the polymerization reaction as a raw material, at least PAS, a sulfidizing agent, a dihalogenated aromatic compound, and a sulfur component 1 in the reaction mixture are used. A method for producing PAS is disclosed in which the reaction is conducted in an organic polar solvent of 1.25 liters or less per mole (see Patent Document 6).

Japanese Patent Publication No. 45-3368 Japanese Patent Laid-Open No. 50-84698 JP-A-62-197422 JP-A-8-239474 Japanese Patent Laid-Open No. 4-7334 JP 2010-70702 A

  In the production method as described in Patent Document 1, only a PAS having a low molecular weight and a low melt viscosity could be produced. As a general method for obtaining a high molecular weight body, a method of increasing the reaction concentration can be considered, but in the case of the production method, the reaction hardly proceeds as the reaction concentration increases, and the molecular weight of the obtained PAS is rather lowered. Therefore, a method for increasing the molecular weight has been demanded.

  In the production method of Patent Document 2, the addition amount of the polymerization aid is required to be equimolar or more with respect to the alkali metal sulfide. Furthermore, in this method, in order to separate and recover the polymerization aid during the recovery of PAS after the polymerization reaction, a complicated incidental equipment and a large amount of cost are required, and a more efficient method has been demanded.

  The method of Patent Document 3 is a method of increasing the molecular weight by thermally cross-linking PAS after the polymerization reaction, and additionally requires a heat treatment step, so that a complicated process and a large amount of heat energy are required. It was a method. In addition, the obtained crosslinked PAS is mechanically fragile and difficult to be processed into a film, sheet, fiber or the like, and a high molecular weight method that does not depend on crosslinking has been demanded.

  The method of Patent Document 4 is a technique for increasing the molecular weight of PAS after polymerization reaction without using thermal crosslinking. In this method, the amount of covalently bonded chlorine in PPS used as a raw material is precisely measured. This is a technique inferior in processability because it requires complicated operations for measuring the total chlorine amount and ionic chlorine amount of PPS before the reaction.

  In the method of Patent Document 5, an alkali metal sulfide is allowed to act on PAS used as a raw material to synthesize a prepolymer having an alkali thiolate group at at least one end (depolymerization step), and the obtained prepolymer It requires a multi-step process (polymerization process) of reacting the dihalogenated aromatic compound with a large number of facilities and complicated operations, and therefore there is room for improvement.

  In the method of Patent Document 6, at least PAS, a sulfidizing agent, and a dihalogenated aromatic compound are reacted in one step in an organic polar solvent of 1.25 liters or less with respect to 1 mol of a sulfur component in the reaction mixture. This method is disclosed only when 25 mol% or more of a sulfidizing agent and a dihalogenated aromatic compound are used relative to the sulfur component of PAS used as a raw material, and the sulfidizing agent and dihalogenated for PAS used as a raw material are disclosed. Due to the large amount of aromatic compound used, there was room for improvement such as an increase in raw material costs. In addition, there is no description about a case where the reaction is performed using 5 mol% or less of a sulfidizing agent with respect to PAS used as a raw material.

  The present invention employs the following means in order to solve such problems.

That is, the present invention
[1] A polyarylene sulfide is produced by adding a sulfidizing agent (b) and a dihalogenated aromatic compound (c) to a polyarylene sulfide (a) and reacting by heating in an organic polar solvent (d). A method for producing polyarylene sulfide, comprising adding 0.5 mol or more and less than 5 mol of sulfidizing agent (b) to 100 mol of sulfur component in polyarylene sulfide (a).
[2] The polyarylene sulfide according to [1], wherein 0.5 to 5 mol of the dihalogenated aromatic compound (c) is added to 100 mol of the sulfur component in the polyarylene sulfide (a). Production method.
[3] The polyhalogenated compound according to any one of [1] or [2], wherein 0.5 mol to 2 mol of the dihalogenated aromatic compound (c) is added to 1 mol of the sulfidizing agent (b). A process for producing arylene sulfide.
[4] The polyarylene according to any one of [1] to [3], wherein the weight average molecular weight of the produced polyarylene sulfide is more than 1.0 times the weight average molecular weight of the starting polyarylene sulfide (a). A method for producing sulfide.
[5] A polyarylene sulfide (a) is heated by heating a reaction mixture containing at least a sulfidizing agent, a dihalogenated aromatic compound, and an organic polar solvent of 1.25 liters or more with respect to 1 mol of a sulfur component in the reaction mixture. A method for producing polyarylene sulfide, which is obtained by the method according to any one of [1] to [4].
[6] A polyarylene sulfide and an oligoarylene sulfide are heated by heating a reaction mixture containing at least a sulfiding agent, a dihalogenated aromatic compound, and an organic polar solvent of 1.25 liters or more with respect to 1 mol of a sulfur component in the reaction mixture. A polyarylene sulfide (a) is obtained by synthesizing the oligoarylene sulfide after the synthesis of the mixture, and then producing the polyarylene sulfide by the method according to any one of [1] to [5] above A process for producing arylene sulfide.

  According to the present invention, a method for producing a polyarylene sulfide having a molecular weight larger than that of a polyarylene sulfide used as a raw material can be provided.

  Embodiments of the present invention will be described below.

(1) Sulfiding agent The sulfiding agent used in the embodiment of the present invention may be any one that can introduce a sulfide bond into a dihalogenated aromatic compound, such as an alkali metal sulfide, an alkali metal hydrosulfide, and An example is hydrogen sulfide.

  Specific examples of the alkali metal sulfide include lithium sulfide, sodium sulfide, potassium sulfide, rubidium sulfide, cesium sulfide and a mixture 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 generally available inexpensive alkali metal sulfides are hydrates or aqueous mixtures, it is preferred to use such forms of alkali metal sulfides.

  Specific examples of the alkali metal hydrosulfide include, for example, lithium hydrosulfide, sodium hydrosulfide, potassium hydrosulfide, lithium hydrosulfide, rubidium hydrosulfide, cesium hydrosulfide, and a mixture of two or more thereof. Of these, lithium hydrosulfide and / or sodium hydrosulfide are preferable, and sodium hydrosulfide is more preferably used.

  Moreover, the alkali metal sulfide produced | generated in a reaction system from an alkali metal hydrosulfide and an alkali metal hydroxide can also be used. Alternatively, an alkali metal sulfide prepared by previously contacting an alkali metal hydrosulfide and an alkali metal hydroxide can be used. These alkali metal hydrosulfides and alkali metal hydroxides can be used in the form of compounds selected from hydrates, aqueous mixtures, and anhydrides. Hydrates or aqueous mixtures are preferred from the standpoint of availability and cost.

  Furthermore, alkali metal sulfides generated in the reaction system from alkali metal hydroxides such as lithium hydroxide and sodium hydroxide and hydrogen sulfide can also be used. Further, alkali metal sulfides prepared by previously contacting alkali metal hydroxides such as lithium hydroxide and sodium hydroxide with hydrogen sulfide can also be used. Hydrogen sulfide can be used in any form of gas, liquid, and aqueous solution.

  In the embodiment of the present invention, the amount of the sulfidizing agent means a residual amount obtained by subtracting the loss from the actual charge when there is a partial loss of the sulfidizing agent before the start of the reaction due to dehydration operation or the like. Shall.

  An alkali metal hydroxide and / or an alkaline earth metal hydroxide can be used in combination with the sulfidizing agent. Specific examples of the alkali metal hydroxide include sodium hydroxide, potassium hydroxide, lithium hydroxide, rubidium hydroxide, cesium hydroxide, and a mixture of two or more of these. Specific examples of the alkaline earth metal hydroxide include calcium hydroxide, strontium hydroxide, and barium hydroxide, and sodium hydroxide is preferably used.

  When an alkali metal hydrosulfide is used as the sulfiding agent, it is particularly preferable to use an alkali metal hydroxide at the same time. In this case, the amount of alkali metal hydroxide used can be 0.95 mol or more, preferably 1.00 mol or more, more preferably 1.005 mol, per 1 mol of alkali metal hydrosulfide. That's it. Moreover, it can be 5.0 mol or less, Preferably it is 4.5 mol or less, More preferably, it is 4.0 mol or less. When hydrogen sulfide is used as the sulfiding agent, it is particularly preferable to use an alkali metal hydroxide at the same time. In this case, the amount of the alkali metal hydroxide used can be 2.0 mol or more, preferably 2.01 mol or more, more preferably 2.04 mol or more with respect to 1 mol of hydrogen sulfide. . Moreover, it can be 6.0 mol or less, Preferably it is 5.5 mol or less, More preferably, it is 5.0 mol or less.

(2) Dihalogenated aromatic compound The dihalogenated aromatic compound used in the embodiment of the present invention is an aromatic compound having an arylene group which is a divalent group of an aromatic ring and two halogeno groups. One mole of the dihalogenated aromatic compound has 1 mole of an arylene unit and 2 moles of a halogeno group. For example, compounds having a phenylene group which is a divalent group of a benzene ring as an arylene group and two halogeno groups include p-dichlorobenzene, o-dichlorobenzene, m-dichlorobenzene, p-dibromobenzene, o-dibromo. Mention may be made of dihalogenated benzenes 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. Mention may also be made of compounds containing substituents other than halogen, such as -2,5-dichlorobenzene and 3,5-dichlorobenzoic acid. Especially, the dihalogenated aromatic compound which has p-dihalogenated benzene represented by p-dichlorobenzene as a main component is preferable. Particularly preferably, it contains 80 to 100 mol%, more preferably 90 to 100 mol% of p-dichlorobenzene.

(3) Organic polar solvent Although an organic polar solvent is used in the present invention, an organic amide solvent is particularly preferable. 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, An aprotic organic solvent typified by 3-dimethyl-2-imidazolidinone, N, N-dimethylacetamide, N, N-dimethylformamide, hexamethylphosphoric triamide, etc., and a mixture thereof, have a stable reaction. It is preferably used because it is expensive. Of these, N-methyl-2-pyrrolidone and 1,3-dimethyl-2-imidazolidinone are preferably used.

(4) Polyarylene sulfide (a)
The polyarylene sulfide (a) used as a raw material in the present invention is a compound having a repeating unit of the formula-(Ar-S)-as a main constituent unit, preferably a linear shape containing 80 mol% or more of the repeating unit. Homopolymers or linear copolymers. Ar includes units represented by the following formulas (A) to (L), among which the formula (A) is particularly preferable.

(In the formula, R1 and R2 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 or different. May be good.)

  As long as this repeating unit is a main structural unit, it can contain a small amount of branching units or crosslinking units represented by the following formulas (M) to (P). The amount of copolymerization of these branched units or cross-linked units is preferably in the range of 0 to 1 mol% with respect to 1 mol of the main structural unit represented by-(Ar-S)-.

  In addition, the polyarylene sulfide in the embodiment of the present invention may be any of a random copolymer, a block copolymer and a mixture thereof containing the above repeating unit.

  Typical examples thereof include polyphenylene sulfide, polyphenylene sulfide sulfone, polyphenylene sulfide ketone, random copolymers thereof, block copolymers thereof, and mixtures thereof. Particularly preferred PASs include p-phenylene sulfide units as the main structural unit of the polymer.

Of polyphenylene sulfide (hereinafter sometimes abbreviated as PPS), polyphenylene sulfide sulfone, and polyphenylene sulfide ketone.

  Here, in the embodiment of the present invention, the molecular weight of PAS is not particularly limited, but the weight average molecular weight of general PAS can be exemplified as 2,000 to 1,000,000, preferably 2,500 to 500,000. It can be illustrated and 3,000-100,000 can be illustrated more preferably.

  The polyarylene sulfide (a) used in the present invention tends to exhibit the effect of increasing the molecular weight, which is a feature of the present invention, as the weight average molecular weight is lower. The preferable upper limit of the weight average molecular weight is 50,000 or less. More preferably 20,000 or less, still more preferably 18,000 or less, even more preferably 15,000 or less, and most preferably less than 12,000. Moreover, the minimum with a preferable weight average molecular weight is 3,000 or more, More preferably, it is 4,000 or more, More preferably, it is 5,000 or more. In addition, such polyarylene sulfides in the weight average molecular weight region generally have a low melt viscosity and are difficult to use for various applications such as resins, fibers, and films. Therefore, in order to use such a polyarylene sulfide having a weight average molecular weight region in each application, it is necessary to increase the molecular weight, which is preferable because the effect of the present invention is high.

  The production method of the polyarylene sulfide (a) used in the present invention is not particularly limited, and any production method can be used. For example, an alkali metal sulfide represented by Patent Document 1 described above can be used. It can be obtained by a method of reacting a polyhalogenated aromatic compound in an organic amide solvent. Further, PAS produced under dilute conditions using an organic polar solvent of 1.25 liters or more per 1 mol of sulfur component in the reaction mixture as disclosed in JP-A-2015-127398 can be preferably used. . The polyarylene sulfide obtained by such a method generally has a low weight average molecular weight and is difficult to use in each application, but can be increased in molecular weight and improved in value by the method of the present invention. This is an example in which the characteristics of

  Further, as disclosed in JP-A-2009-30012, a sulfidizing agent and a dihalogenated aromatic compound are used in an organic polar solvent of 1.25 liters or more with respect to 1 mol of sulfur atom of the sulfidizing agent. When a cyclic polyarylene sulfide is produced, a linear polyarylene sulfide that has a generally low weight average molecular weight and is difficult to use in each application is by-produced. The linear polyarylene sulfide obtained after the separation of the cyclic polyarylene sulfide and having a low weight average molecular weight can also be increased in molecular weight by the method of the present invention and can be improved in value. This is an example.

  In addition, it is possible to use a wide range of molded products, molded scraps, waste plastics, off-spec products, etc. using the manufactured PAS.

  The form of PAS is not particularly limited, and may be a dry powder, powder, granule, or pellet, and may be used in a state containing an organic polar solvent as a reaction solvent. It is also possible to use in a state containing a third component that does not inhibit the reaction. Examples of such a third component include inorganic fillers, and PAS in the form of a resin composition containing inorganic fillers can also be used.

(5) Oligoarylene sulfide The oligoarylene sulfide in the present invention is a homopolymer or copolymer containing a repeating unit of the formula-(Ar-S)-as a main constituent unit, preferably containing 80 mol% or more of the repeating unit. . Ar includes units represented by the above formulas (A) to (L), among which the formula (A) is particularly preferable.

  In addition, the oligoarylene sulfide in the present invention may be any of a random copolymer, a block copolymer and a mixture thereof containing the repeating unit. Typical examples of these include oligophenylene sulfide, oligophenylene sulfide sulfone, oligophenylene sulfide ketone, random copolymers thereof, block copolymers, and mixtures thereof. Particularly preferred oligoarylene sulfides include oligophenylene sulfide sulfones and oligophenylene sulfide ketones in addition to oligophenylene sulfides containing 80 mol% or more, particularly 90 mol% or more of p-phenylene sulfide units as main structural units.

  The average molecular weight of various oligoarylene sulfides in the present invention can be defined to be lower than that of the aforementioned PAS, and examples of the weight average molecular weight of general oligoarylene sulfides include 200 to 2,000.

  Moreover, there is no restriction | limiting in particular in the structure of the oligoarylene sulfide of this invention, Various structures, such as a linear structure, a branched structure, a graft structure, and a cyclic structure, and mixtures thereof are accept | permitted. Among these, linear and / or cyclic oligoarylene sulfides are preferable, and there is an advantage that a strict reaction control and a third component for introducing a branched structure are not required to obtain these structures.

  Moreover, when the polyarylene sulfide (a) used as a raw material contains an oligoarylene sulfide, the oligoarylene sulfide can be separated from the polyarylene sulfide and used for the reaction. For example, the linear polyarylene sulfide obtained by separating the cyclic polyarylene sulfide described in the above section (4) is an example.

  There is no particular limitation on the method for separating the polyarylene sulfide and the oligoarylene sulfide, and a known method may be used.

  As a method for separating oligoarylene sulfide from a PAS component, a separation method using a difference in solubility between polyarylene sulfide and oligoarylene sulfide, more specifically, high solubility in oligoarylene sulfide, while oligoarylene sulfide is high. An example is a method in which an oligoarylene sulfide is removed as a solvent-soluble component by bringing a solvent having poor solubility in PAS into contact with a PAS component under heating, if necessary, under conditions where the solvent dissolves.

  The solvent used for removing the oligoarylene sulfide is not particularly limited as long as it is a solvent capable of dissolving the oligoarylene sulfide. However, in the dissolving environment, a solvent that dissolves the oligoarylene sulfide but hardly dissolves the PAS is preferable. Solvents that do not dissolve are more preferred. The pressure of the reaction system when the PAS component is brought into contact with the solvent is preferably normal pressure or slight pressure, and particularly preferably normal pressure. In the reaction system of such pressure, the members of the reactor for constructing it are inexpensive. There are advantages. From this point of view, it is desirable that the reaction system pressure avoid pressurizing conditions that require an expensive pressure vessel. As the solvent to be used, those which do not substantially cause undesirable side reactions such as decomposition and crosslinking of the PAS component are preferable. For example, when the operation of bringing the PAS component into contact with the solvent is performed under atmospheric pressure reflux conditions, Hydrocarbon solvents such as hexane, cyclohexane, benzene, toluene, xylene, halogen solvents such as chloroform, methylene chloride, 1,2-dichloroethane, chlorobenzene, ether solvents such as tetrahydrofuran, diisopropyl ether, N, N-dimethylformamide , N, N-dimethylacetamide, dimethyl sulfoxide, N-methyl-2-pyrrolidone, 1,3-dimethyl-2-imidazolidinone, N, N-dimethylimidazolidinone, and the like.

  There are no particular restrictions on the atmosphere in which the PAS component is brought into contact with the solvent, but if the PAS component or solvent is subject to oxidative degradation due to conditions such as the temperature or time at which it is brought into contact, it should be performed in a non-oxidizing atmosphere. Is desirable. Note that the non-oxidizing atmosphere is an atmosphere having a gas phase oxygen concentration of 5% by volume or less, preferably 2% by volume or less, more preferably an oxygen-free atmosphere such as nitrogen, helium, argon, or the like. Among these, a nitrogen atmosphere is particularly preferable from the viewpoints of economy and ease of handling.

  The temperature at which the PAS component is brought into contact with the solvent is not particularly limited. Generally, the higher the temperature, the more the oligoarylene sulfide is dissolved in the solvent. However, when the molecular weight of the PAS is low, the dissolution of the PAS is also promoted. It tends to be. The greater the difference between the molecular weight of PAS and the oligoarylene sulfide, the greater the difference in solubility with the oligoarylene sulfide. Therefore, even if the PAS component is contacted with the solvent at a high temperature, only the oligoarylene sulfide is preferably used. It tends to be removed. Further, as described above, since the contact of the PAS component with the solvent is preferably performed under atmospheric pressure, the upper limit temperature is preferably set to the reflux condition temperature under the atmospheric pressure of the solvent used. In the case of using a preferred solvent, for example, 20 to 150 ° C., preferably 30 to 100 ° C. can be exemplified as a specific temperature range.

  The time during which the PAS component is brought into contact with the solvent varies depending on the type of solvent used, the temperature, etc., and thus cannot be uniquely limited. For example, 1 minute to 50 hours can be exemplified, and in such a range, the oligoarylene sulfide is dissolved in the solvent. Tend to be sufficient.

  The method for bringing the PAS component into contact with the solvent is not particularly limited as long as a known general method is used. For example, the PAS component and the solvent are mixed and stirred as necessary, and then the solution portion is recovered. Any method can be used such as a method of dissolving the oligoarylene sulfide in the solvent simultaneously with showering the solvent on the PAS component on the filter and a method based on the principle of the Soxhlet extraction method.

  When the solution in which the oligoarylene sulfide is dissolved is obtained in the form of a solid-liquid slurry containing solid PAS after contacting the PAS component with a solvent, the solution portion can be removed using a known solid-liquid separation method. preferable. Examples of the solid-liquid separation method include separation by filtration, centrifugation, and decantation. When the solid component of PAS obtained after this treatment contains the solvent used in the treatment, it is possible to perform drying or the like as necessary to remove the solvent.

(6) Production method of polyarylene sulfide (e) In the present invention, the polyarylene sulfide (a) is added to the dihalogenated aromatic compound (c) and 100 mol of the sulfur component in the polyarylene sulfide (a). The polyarylene sulfide (e) is produced by adding 5 mol or more and less than 5 mol of the sulfidizing agent (b) and reacting by heating in the organic polar solvent (d). Here, the “number of moles” of the sulfur component in the polyarylene sulfide is the “number of repeating units” of the polymer containing one sulfur atom. For example, one molecule of polyarylene sulfide having a polymerization degree of 100 is calculated as 100 mol, not 1 mol. As long as the essence of the present invention is not impaired, a compound containing a sulfur component in addition to polyarylene sulfide and a sulfidizing agent can be additionally present in the reaction mixture. Sulfur components derived from sulfur-containing compounds that do not substantially act on the reaction need not be taken into account.

  Below, the preferable aspect regarding manufacture of polyarylene sulfide (e) in this invention is explained in full detail.

  The use amount of the sulfidizing agent (b) of the present invention is 0.5 mol or more and less than 5 mol with respect to 100 mol of the sulfur component in the polyarylene sulfide (a). The preferable lower limit of the amount of the sulfiding agent (b) used relative to 100 mol of the sulfur component in the polyarylene sulfide (a) is 0.7 mol or more, more preferably 1.0 mol or more, and further preferably 1 .2 moles or more. Moreover, a preferable upper limit is 4.7 mol or less, More preferably, it is 4.5 mol or less, More preferably, it is 4.0 mol or less. In such a preferable range, the polyarylene sulfide (e) to be produced tends to have a high molecular weight. On the other hand, when the amount of the sulfiding agent (b) used is less than 0.5 mol, the reaction does not proceed sufficiently and the weight average molecular weight does not improve. When the amount of the sulfidizing agent (b) used exceeds 5 moles, there is little improvement in the weight average molecular weight of the polyarylene sulfide produced under specific conditions, or the amount of the sulfidizing agent used is increased. Inferior to

  The amount of the dihalogenated aromatic compound (c) of the present invention is preferably 0.2 mol or more, more preferably 0.5 mol or more, relative to 100 mol of the sulfur component in the polyarylene sulfide (a). 0 mol or more is more preferable, and 1.2 mol or more is particularly preferable. Moreover, the upper limit with the preferable usage-amount of the dihalogenated aromatic compound (c) with respect to 100 mol of sulfur components in polyarylene sulfide (a) is less than 5 mol, More preferably, it is 4.7 mol or less, 4.5 mol or less. Is more preferably 4.0 mol or less. When the amount of the dihalogenated aromatic compound (c) used is in such a preferable range, the weight average molecular weight of the polyarylene sulfide to be produced tends to be improved. Further, the dihalogenated aromatic compound (c) may be reacted in its entirety at once, or may be divided for use in the reaction.

  Furthermore, the amount of the dihalogenated aromatic compound (c) used is preferably in the range of 0.5 mol or more and 2 mol or less with respect to 1 mol of the sulfidizing agent (b), and 0.7 mol or more and 1. It is more preferably 9 mol or less, and further preferably 0.9 mol or more and 1.8 mol or less. In such a preferable range, the weight average molecular weight of polyarylene sulfide tends to be improved.

  In the present invention, the amount of the organic polar solvent (d) used is more efficient, and the viewpoint that the polyarylene sulfide (e) having a higher molecular weight than the polyarylene sulfide (a) used as a raw material, which is a feature of the present invention, is produced. Therefore, it is preferable not to use a large amount. The upper limit of the amount of the organic polar solvent (d) used is preferably 10 liters or less, more preferably 8 liters or less, and even more preferably 5 liters or less with respect to 1 mole of sulfur atoms in the reaction mixture. In addition, when the polyarylene sulfide (a) used as a raw material is dissolved and the reaction is uniform, the tendency to increase the molecular weight is strong, and it depends on the structure of the polyarylene sulfide (a). The amount of the organic polar solvent (d) used is preferably 0.1 liters or more, more preferably 0.2 liters or more, relative to 1 mole of sulfur atoms therein. The amount of the organic polar solvent used here is based on the volume of the organic polar solvent under normal temperature and pressure, and is based on the amount of the organic polar solvent at the start of the reaction. By reducing the amount of the organic polar solvent used here, the time required for the reaction can be shortened, and the weight average molecular weight of the resulting polyarylene sulfide (e) tends to be improved.

  Also, the amount of the organic polar solvent (d) used should be adjusted so that the concentration of the sulfur component in the raw material mixture is higher than the concentration of the sulfur component when the polyarylene sulfide (a) used as the raw material is synthesized. Thus, the tendency of the molecular weight of the resulting polyarylene sulfide (e) to increase is increased.

  For example, in a method of reacting an alkali metal sulfide such as sodium sulfide with a polyhaloaromatic compound such as p-dichlorobenzene in an organic polar solvent such as N-methyl-2-pyrrolidone widely used in industry, When polyarylene sulfide synthesized using 1.25 to 10 liters of an organic polar solvent is used as polyarylene sulfide (a) with respect to 1 mol of sulfur atom of the sulfiding agent, 1 mol of sulfur atom in the reaction mixture is used. On the other hand, by using less than 1.25 liters of the organic polar solvent (d), the tendency of improving the molecular weight of the polyarylene sulfide (e) to be produced becomes strong.

  In the present invention, the polyarylene sulfide (a) is added to the dihalogenated aromatic compound (c) and the sulfur component in the polyarylene sulfide (a) in an amount of 0.5 mol or more and less than 5 mol of the sulfurizing agent (b The reaction temperature when heating and reacting in the organic polar solvent (d) varies depending on the type and amount of the organic polar solvent, but cannot be uniquely determined. C., preferably 180 to 320.degree. C., more preferably 220 to 300.degree. C., still more preferably 225 to 280.degree. In this preferable temperature range, a higher reaction rate can be obtained, and the reaction can be shortened. Further, since the polyarylene sulfide (a) used as a raw material is easily dissolved, the reaction tends to be uniform and easily proceed. The reaction may be either a one-stage reaction performed at a constant temperature, a multi-stage reaction in which the temperature is raised stepwise, or a reaction in which the temperature is continuously changed.

  The reaction time depends on the type and amount of the raw material used or the reaction temperature and cannot be defined unconditionally. However, it is preferably 0.1 hour or longer, more preferably 0.5 hour or longer. By setting it as this preferable time or more, since unreacted raw material components can be reduced, the weight average molecular weight of the polyarylene sulfide (e) tends to be improved. On the other hand, the reaction time is not particularly limited, but the reaction proceeds sufficiently even within 40 hours, preferably within 10 hours, more preferably within 6 hours.

  In the present invention, the conversion rate of the dihalogenated aromatic compound (c) is preferably reacted up to 10% or more, more preferably 20% or more, further preferably 30% or more. In such a state, it is considered that the dihalogenated aromatic compound (c) reacts and is likely to be incorporated into the polyarylene sulfide structure, and the weight average molecular weight of the polyarylene sulfide (e) tends to be improved. If it is said preferable reaction temperature and reaction time, it will become such a preferable range easily.

The conversion rate of the dihalogenated aromatic compound is a value calculated by the following formula. The residual amount of the dihalogenated aromatic compound can be usually determined by gas chromatography.
(A) When dihalogenated aromatic compound is added excessively in a molar ratio with respect to the alkali metal sulfide, conversion rate (%) = [prepared amount of dihalogenated aromatic compound (mol) −remaining dihalogenated aromatic compound Amount (mol)] / [preparation amount of dihalogenated aromatic compound (mol) −excess amount of dihalogenated aromatic compound (mol)] × 100
(B) In cases other than (a) above, conversion rate (%) = [preparation amount of dihalogenated aromatic compound (mol) −remaining amount of dihalogenated aromatic compound (mol)] / [preparation of dihalogenated aromatic compound] Amount (mole)] × 100

  In the PAS production method of the present invention, the order in which the polyarylene sulfide (a), the sulfidizing agent (b), the dihalogenated aromatic compound (c), and the organic polar solvent (d) are charged into the reactor is not particularly limited. In addition to the essential components, a third component that does not significantly inhibit the reaction and a third component that has an effect of accelerating the reaction can be added to the reaction mixture. Although there is no restriction | limiting in particular in the method of performing reaction, Performing on stirring conditions is preferable for homogenization of a reaction system. In addition, there is no restriction | limiting in particular in the temperature at the time of charging the said raw material, For example, you may react after charging a raw material near room temperature, or charge a raw material in the reactor temperature-controlled beforehand to the temperature preferable for reaction mentioned above. It is also possible to carry out the reaction.

  In addition, the well-known various polymerization systems, such as a batch system and a continuous method, and a reaction system are employable as the method of making it react. Further, the atmosphere in the production is preferably a non-oxidizing atmosphere, preferably in an inert gas atmosphere such as nitrogen, helium, and argon. From the viewpoint of economy and ease of handling, a nitrogen atmosphere is preferable.

  In the present invention, a part of the organic polar solvent (d) contained in the reaction mixture after reacting the polyarylene sulfide (a), the sulfidizing agent (b), and the dihalogenated aromatic compound (c) is distilled off. Thus, an operation of reducing the amount of the organic polar solvent in the reaction mixture can be additionally performed.

  As a method for distilling off the organic polar solvent (d), any method is not particularly limited as long as the organic polar solvent can be separated from the reaction mixture and the amount of the organic polar solvent contained in the reaction mixture can be reduced. Preferable methods include a method of distilling the organic polar solvent under reduced pressure or increased pressure, a method of removing the solvent by flash transfer, etc., and a method of distilling the organic polar solvent under reduced pressure or increased pressure is particularly preferable. Further, when distilling the organic polar solvent under reduced pressure or under pressure, an inert gas such as nitrogen, helium, or argon may be used as a carrier gas.

(7) Recovery method of polyarylene sulfide (e) In the production of the polyarylene sulfide of the present invention, it is also possible to separate and recover the polyarylene sulfide (e) from the reaction mixture obtained by the reaction described above. The reaction mixture obtained by the reaction contains polyarylene sulfide (e) and an organic polar solvent, and may contain unreacted sulfidizing agent, dihalogenated aromatic compound, water, by-product salt, etc. as other components. is there.

  There is no particular limitation on the method for recovering the PAS component from the reaction mixture. For example, if part or most of the organic polar solvent is removed by an operation such as distillation as necessary, the solubility in the PAS component is low and the organic polar solvent is used. And a method of recovering it as a mixed solid of PAS components by contacting with a solvent having solubility in by-product salts, if necessary, under heating as necessary.

  Solvents having such characteristics are generally relatively polar solvents, and preferred solvents differ depending on the type of organic polar solvent and by-product salt used, but are not limited, for example, water, methanol, ethanol, propanol, Examples include alcohols typified by isopropanol, butanol and hexanol, ketones typified by acetone, and acetates typified by ethyl acetate and butyl acetate. From the viewpoint of availability and economy, water, methanol and acetone Are preferred, and 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 by-product salt contained in the mixed solid of the PAS component. Since the PAS component is precipitated as a solid component by this treatment, the PAS component can be recovered using a known solid-liquid separation method. Examples of the solid-liquid separation method include separation by filtration, centrifugation, and decantation. These series of treatments can be repeated several times as necessary, and this tends to further reduce the amount of the organic polar solvent and by-product salt contained in the mixed solid of the PAS component.

  Moreover, as a method of the treatment with the above-mentioned solvent, there is a method of mixing a solvent and a reaction mixture, and it is possible to appropriately stir or heat as necessary. Although there is no restriction | limiting in particular in the temperature at the time of performing the process by a solvent, 20 to 220 degreeC is preferable and 50 to 200 degreeC is still more preferable. In such a range, for example, by-product salt can be easily removed, and the treatment can be performed at a relatively low pressure, which is preferable. Here, when water is used as the solvent, the water is preferably distilled water or deionized water, but if necessary, formic acid, acetic acid, propionic acid, butyric acid, chloroacetic acid, dichloroacetic acid, acrylic acid, crotonic acid, Organic acidic compounds such as benzoic acid, salicylic acid, oxalic acid, malonic acid, succinic acid, phthalic acid, fumaric acid, and their alkali metal salts, alkaline earth metal salts, sulfuric acid, phosphoric acid, hydrochloric acid, carbonic acid, silicic acid, etc. It is also possible to use an aqueous solution containing a compound and ammonium ions. When the mixed solid of the PAS component obtained after this treatment contains the solvent used in the treatment, it is possible to perform drying or the like as necessary to remove the solvent. Here, it is desirable to remove the solvent at least 50% by weight or more, preferably 70% by weight or more, more preferably 90% by weight or more, and still more preferably 95% by weight or more. Although the temperature at which the solvent is removed by heating depends on the characteristics of the solvent used, it cannot be limited uniquely. However, the temperature can usually be selected from 20 to 150 ° C, preferably from 40 to 120 ° C. In addition, the pressure for removing the solvent is preferably normal pressure or lower, which makes it possible to remove the solvent at a lower temperature.

(8) Characteristics of polyarylene sulfide (e) obtained by the present invention The polyarylene sulfide (e) obtained by the present invention is characterized by having a higher weight average molecular weight than the polyarylene sulfide (a) used as a raw material. It is. That is, the ratio of the weight average molecular weight of the generated polyarylene sulfide (e) to the weight average molecular weight of the starting polyarylene sulfide (a) (weight average molecular weight of the generated polyarylene sulfide (e) / weight average of the starting polyarylene sulfide (a). The molecular weight) is more than 1.0 times, preferably 1.2 times or more, more preferably 1.5 times or more, still more preferably 2 times or more, and even more preferably 2.1 times or more. is there. Therefore, not only the quality of polyarylene sulfide (a) can be improved, but also low molecular weight polyarylene sulfide, which has not been used for each purpose and has been discarded, can be used for each purpose. Is possible.

  In addition, the ratio of the weight average molecular weight of the produced polyarylene sulfide (e) to the weight average molecular weight of the raw material polyarylene sulfide (a) tends to be 20 times or less, and tends to be 15 times or less.

  Furthermore, another effect of the present invention is an effect of reducing the chlorine content of the generated polyarylene sulfide (e) as compared with the raw material polyarylene sulfide (a). The reason for this is not clear, but the covalently bonded chlorine present at the terminal of the polyarylene sulfide (a) reacts with the added sulfidizing agent (b), and the reaction proceeds from this to the high molecular weight. It is presumed that it will become chlorinated and low chlorinated.

(9) Use of polyarylene sulfide (e) The polyarylene sulfide (e) obtained in the present invention is excellent in heat resistance, chemical resistance, flame retardancy, electrical properties and mechanical properties, and is injection molded and injection compressed. In addition to molding and blow molding applications, extrusion molding such as sheets, films, fibers and pipes can be performed by extrusion molding. At this time, PAS may be used alone, or, if desired, inorganic fillers such as glass fiber, carbon fiber, titanium oxide, calcium carbonate, antioxidant, heat stabilizer, ultraviolet absorber, colorant, etc. Can also be added, and resin can also be mix | blended.

  Examples of the application include electrical / electronic parts, household / office electrical product parts, optical equipment / precision machine-related parts, watering parts, automobile / vehicle-related parts, and other industrial applications.

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

<Measurement of conversion rate of dihalogenated aromatic compound>
The conversion rate of the dihalogen aromatic compound was quantitatively analyzed by gas chromatography (GC) analysis. GC measurement conditions are shown below.
Device: GC-2010 manufactured by Shimadzu Corporation
Column: DB-5 manufactured by J & W Company 0.32 mm × 30 m (0.25 μm)
Carrier gas: Helium detector: Flame ionization detector (FID)

<Molecular weight measurement>
The molecular weight of polyphenylene sulfide was calculated in terms of polystyrene by gel permeation chromatography (GPC) which is a kind of size exclusion chromatography (SEC). The measurement conditions for GPC are shown below.
Equipment: Senshu Science SSC-7100
Column name: Shodex UT-806M
Eluent: 1-chloronaphthalene detector: differential refractive index detector Column temperature: 210 ° C
Pre-constant temperature: 250 ° C
Pump bath temperature: 50 ° C
Detector temperature: 210 ° C
Flow rate: 1.0 mL / min
Sample injection amount: 300 μL (slurry: about 0.2% by weight).

  [Reference Example 1] Here, a preparation example of the raw material polyarylene sulfide (a) is shown.

  In a 1 liter autoclave equipped with a stirrer, 23.36 g of a 48% by weight aqueous solution of sodium hydrosulfide (11.21 g (0.200 mol) of sodium hydrosulfide) and 17.50 g of a 48% by weight aqueous solution of sodium hydroxide (water Sodium oxide 8.40 g (0.210 mol)), N-methyl-2-pyrrolidone (NMP) 500 mL, p-dichlorobenzene (p-DCB) 30.00 g (0.204 mol) were charged. The organic polar solvent with respect to 1 mol of sulfur atoms of the sulfiding agent in the reaction mixture was 2.5 liters. The reaction vessel was sealed under nitrogen gas at room temperature and normal pressure, and then heated from room temperature to 200 ° C. over 25 minutes while stirring at 400 rpm. Next, the temperature was raised to 250 ° C. over 35 minutes. After holding at 250 ° C. for 2 hours, it was rapidly cooled to near room temperature.

  As a result of analyzing the obtained content, that is, the reaction mixture by gas chromatography, it was found that the conversion rate of monomer p-DCB was 95%.

  After diluting 500 g of the obtained contents with about 1500 g of ion-exchanged water, it was filtered with a glass filter having an average opening of 10 to 16 micrometers. The filter-on component was dispersed in about 400 g of ion-exchanged water, stirred at 70 ° C. for 15 minutes, and subjected to the same filtration again three times in total to obtain a white solid. This was vacuum-dried at 100 ° C. overnight to obtain a dry solid.

  As a result of analysis, this was polyphenylene sulfide from the absorption spectrum in infrared spectroscopic analysis, and the weight average molecular weight was 10,000. The polyphenylene sulfide obtained here is hereinafter referred to as PPS-1.

  [Reference Example 2] Here, an example in which oligophenylene sulfide was separated from the reaction mixture obtained in Reference Example 1 and polyphenylene sulfide (a) was recovered was shown.

A membrane filter (manufactured by PTFE) having a diameter of 90 mm and a pore diameter of 10 μm was installed on a filter holder KST-90-UH (effective filtration area of about 45.3 parallel centimeters) manufactured by ADVANTEC, and Reference Example 1 About 500 g of the reaction mixture obtained by the described method was charged into a tank.
After sealing the tank, the inside of the tank was pressurized to 0.2 MPa with air, and about 85 g of cake was recovered.

  The obtained cake was diluted with about 400 g of ion-exchanged water, and then filtered through a glass filter having an average opening of 10 to 16 micrometers. The filter-on component was dispersed in about 400 g of ion-exchanged water, stirred at 70 ° C. for 15 minutes, and subjected to the same filtration again three times in total to obtain a white solid. This was vacuum-dried overnight at 100 ° C. to obtain about 15 g of a dry solid.

  As a result of analysis, this was polyphenylene sulfide and the weight average molecular weight was 11,500 from the absorption spectrum in infrared spectroscopic analysis. The polyphenylene sulfide obtained here is hereinafter referred to as PPS-2.

[Example 1]
<Reaction>
In a 0.2 liter autoclave equipped with a stirrer, 0.11 g (0.053 g as sodium hydrosulfide) of PPS-1 (5.08 g, 0.047 mol as a sulfur component) and a 48 wt% aqueous solution of sodium hydrosulfide, 0.00094 mol), 0.28 g of a 48 wt% aqueous solution of sodium hydroxide (0.13 g, 0.0034 mol as sodium hydroxide), NMP (120 mL), p-DCB (0.14 g, 0.00095 mol) ). Here, the ratio of the sulfidizing agent to 100 mol of the sulfur component in the polyphenylene sulfide (a) was 2 mol. Moreover, the amount of the organic polar solvent with respect to 1 mol of sulfur atoms in the reaction mixture was 2.5 liters.

  The reaction vessel was sealed under nitrogen gas at room temperature and normal pressure, and then heated from room temperature to 200 ° C. over 25 minutes while stirring at 400 rpm. Next, the temperature was raised to 250 ° C. over 35 minutes. After holding at 250 ° C. for 2 hours, it was rapidly cooled to near room temperature.

  As a result of analyzing the obtained content, that is, the reaction mixture by gas chromatography, it was found that the conversion rate of monomer p-DCB was 51%.

<Recovery>
100 g of the obtained content was diluted with about 300 g of ion-exchanged water, and then filtered through a glass filter having an average opening of 10 to 16 micrometers. The filter-on component was dispersed in about 100 g of ion-exchanged water, stirred at 70 ° C. for 15 minutes, and subjected to the same filtration again three times in total to obtain a white solid. This was vacuum-dried at 100 ° C. overnight to obtain a dry solid.
As a result of analysis, this solid was polyphenylene sulfide and the weight average molecular weight was 13,000 from the absorption spectrum in infrared spectroscopic analysis. It was found that polyphenylene sulfide having a higher molecular weight than that of the polyphenylene sulfide used as a raw material was obtained.

[Example 2]
Here, an example in which polyphenylene sulfide was obtained in the same manner as in Example 1 except that PPS-2 obtained in Reference Example 2 was used instead of PPS-1 is shown.

  Under this condition, polyphenylene sulfide having a weight average molecular weight of 13,500 was obtained. It was found that even when polyphenylene sulfide from which oligophenylene sulfide was removed was used as a raw material, a higher molecular weight polyphenylene sulfide was obtained than the polyphenylene sulfide used as the raw material.

[Example 3]
<Reaction>
In a 0.2 liter autoclave equipped with a stirrer, 0.28 g (0.13 g as sodium hydrosulfide) of PPS-2 (12.72 g, 0.118 mol as a sulfur component) and a 48 wt% aqueous solution of sodium hydrosulfide, 0.0024 mol), 0.70 g of a 48 wt% aqueous solution of sodium hydroxide (0.34 g, 0.0084 mol as sodium hydroxide), NMP (120 mL), p-DCB (0.35 g, 0.0024 mol) ). Here, the ratio of the sulfidizing agent to 100 mol of the sulfur component in the polyphenylene sulfide (a) was 2 mol. Moreover, the amount of the organic polar solvent with respect to 1 mol of sulfur atoms in the reaction mixture was 1.0 liter.

  The reaction vessel was sealed under nitrogen gas at room temperature and normal pressure, and then heated from room temperature to 200 ° C. over 25 minutes while stirring at 400 rpm. Next, the temperature was raised to 250 ° C. over 35 minutes. After holding at 250 ° C. for 2 hours, it was rapidly cooled to near room temperature.

  As a result of analyzing the obtained content, that is, the reaction mixture by gas chromatography, it was found that the conversion rate of monomer p-DCB was 63%.

<Recovery>
In the same manner as in Example 1, polyphenylene sulfide was recovered from the reaction mixture. The resulting polyphenylene sulfide had a weight average molecular weight of 17,000. It was found that by increasing the concentration of the sulfur component during the reaction, the molecular weight tends to increase more than the polyphenylene sulfide used as the raw material.

[Comparative Example 1]
<Reaction>
In a 0.2 liter autoclave equipped with a stirrer, PPS-1 (3.89 g, 0.036 mol as a sulfur component), 1.41 g of a 48 wt% aqueous solution of sodium hydrosulfide (0.68 g as sodium hydrosulfide, 0.012 mol), 1.17 g of a 48 wt% aqueous solution of sodium hydroxide (0.56 g, 0.014 mol as sodium hydroxide), NMP (120 mL), p-DCB (1.76 g, 0.012 mol) ). Here, the ratio of the sulfidizing agent to 100 mol of the sulfur component in the polyphenylene sulfide (a) was 34 mol. Moreover, the amount of the organic polar solvent with respect to 1 mol of sulfur atoms in the reaction mixture was 2.5 liters.

  The reaction vessel was sealed under nitrogen gas at room temperature and normal pressure, and then heated from room temperature to 200 ° C. over 25 minutes while stirring at 400 rpm. Next, the temperature was raised to 250 ° C. over 35 minutes. After holding at 250 ° C. for 2 hours, it was rapidly cooled to near room temperature.

  As a result of analyzing the obtained content, that is, the reaction mixture by gas chromatography, it was found that the conversion rate of monomer p-DCB was 89%.

<Recovery>
In the same manner as in Example 1, polyphenylene sulfide was recovered from the reaction mixture. The resulting polyphenylene sulfide had a weight average molecular weight of 10,000.

  When the reaction was performed using 5 mol or more of a sulfidizing agent with respect to 100 mol of the sulfur component in the raw material polyarylene sulfide (a), the molecular weight of the resulting polyarylene sulfide was not improved.

[Comparative Example 2]
<Reaction>
In a 0.2 liter autoclave equipped with a stirrer, 0.73 g (0.35 g as sodium hydrosulfide) of PPS-1 (4.52 g, 0.042 mol as a sulfur component) and a 48 wt% aqueous solution of sodium hydrosulfide, 0.0062 mol), 0.72 g of a 48 wt% aqueous solution of sodium hydroxide (0.35 g, 0.0086 mol as sodium hydroxide), NMP (120 mL), p-DCB (0.92 g, 0.0062 mol) ). Here, the ratio of the sulfidizing agent to 100 mol of the sulfur component in the polyphenylene sulfide (a) was 15 mol. Moreover, the amount of the organic polar solvent with respect to 1 mol of sulfur atoms in the reaction mixture was 2.5 liters.

  The reaction vessel was sealed under nitrogen gas at room temperature and normal pressure, and then heated from room temperature to 200 ° C. over 25 minutes while stirring at 400 rpm. Next, the temperature was raised to 250 ° C. over 35 minutes. After holding at 250 ° C. for 2 hours, it was rapidly cooled to near room temperature.

  As a result of analyzing the obtained content, that is, the reaction mixture by gas chromatography, it was found that the conversion rate of monomer p-DCB was 87%.

<Recovery>
In the same manner as in Example 1, polyphenylene sulfide was recovered from the reaction mixture. The resulting polyphenylene sulfide had a weight average molecular weight of 10,000.

  When the reaction was performed using 5 mol or more of a sulfidizing agent with respect to 100 mol of the sulfur component in the raw material polyarylene sulfide (a), the molecular weight of the resulting polyarylene sulfide was not improved.

[Comparative Example 3]
Here, the reaction was carried out in the same manner as in Example 1 except that p-DCB was not added.

Under this condition, polyphenylene sulfide was obtained with a weight average molecular weight of 8,000.
It was found that when the reaction was carried out without adding p-DCB, the molecular weight was lower than that of polyphenylene sulfide used as a raw material.

[Comparative Example 4]
Here, an experiment was conducted in the same manner as in Example 1 except that 48% by weight aqueous solution of sodium hydrosulfide, 48% by weight aqueous solution of sodium hydroxide, and p-DCB were not added.

  Under this condition, polyphenylene sulfide was obtained with a weight average molecular weight of 10,000. It was found that the molecular weight of the resulting polyarylene sulfide was not improved when the reaction was carried out without adding a 48 wt% aqueous solution of sodium hydrosulfide, a 48 wt% aqueous solution of sodium hydroxide, and p-DCB.

Claims (6)

A method for producing a polyarylene sulfide by adding a sulfidizing agent (b) and a dihalogenated aromatic compound (c) to a polyarylene sulfide (a) and reacting by heating in an organic polar solvent (d). A process for producing polyarylene sulfide, wherein 0.5 to 5 moles of sulfidizing agent (b) is added to 100 moles of sulfur component in polyarylene sulfide (a). The method for producing polyarylene sulfide according to claim 1, wherein the dihalogenated aromatic compound (c) is added in an amount of 0.5 mol or more and less than 5 mol with respect to 100 mol of the sulfur component in the polyarylene sulfide (a). The method for producing polyarylene sulfide according to claim 1, wherein 0.5 mol to 2 mol of the dihalogenated aromatic compound (c) is added to 1 mol of the sulfidizing agent (b). The method for producing polyarylene sulfide according to any one of claims 1 to 3, wherein the weight average molecular weight of the produced polyarylene sulfide is more than 1.0 times the weight average molecular weight of the raw material polyarylene sulfide (a). A polyarylene sulfide (a) is obtained by heating a reaction mixture containing at least a sulfiding agent, a dihalogenated aromatic compound, and an organic polar solvent of 1.25 liters or more with respect to 1 mol of a sulfur component in the reaction mixture, Then, the manufacturing method of the polyarylene sulfide which manufactures a polyarylene sulfide by the method in any one of Claim 1 to 4. A mixture containing polyarylene sulfide and oligoarylene sulfide by heating a reaction mixture containing at least 1.25 liters of an organic polar solvent with respect to 1 mol of sulfur component in the reaction mixture, at least a sulfidizing agent, a dihalogenated aromatic compound A process for producing a polyarylene sulfide, wherein the polyarylene sulfide (a) is obtained by separating the oligoarylene sulfide after the production of the polyarylene sulfide, and then the polyarylene sulfide is produced by the method according to any one of claims 1 to 5.