Polyarylene sulfide copolymer and method for producing same

Abstract

To provide a polyarylene sulfide copolymer having excellent adhesion, and a method for producing the same.SOLUTION: A polyarylene sulfide copolymer includes a structure represented by the formula (A), and a polyarylene sulfide unit as constitutional units, and has a weight average molecular weight Mw of more than 10,000 and a molecular weight distribution of 6.0 or less. (R is a substituent selected from hydrogen, a C1 to 12 alkyl group, and a C6 to 24 arylene group).SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a polyarylene sulfide copolymer having excellent adhesiveness and a method for producing the same. [Background technology]

[0002] Polyarylene sulfides (hereinafter sometimes abbreviated as PAS), typified by polyphenylene sulfide (hereinafter sometimes abbreviated as PPS), are resins that have excellent properties suitable for use as engineering plastics, such as excellent heat resistance, barrier properties, chemical resistance, electrical insulation, moist heat resistance, and flame retardancy. They can also be molded into various molded parts, films, sheets, fibers, etc. by injection molding or extrusion, and are widely used in fields requiring heat resistance and chemical resistance, such as various electrical and electronic components, machine parts, and automotive parts.

[0003] On the other hand, the typical manufacturing method for PPS, a representative PAS, involves the reaction of dichlorobenzene with a sulfidizing agent, which results in a simple main chain structure consisting primarily of benzene rings and sulfur atoms, and the absence of functional groups, which results in relatively poor adhesion to other resins and materials, and improvements in this area were needed.

[0004] The cyano group is an electron-withdrawing polar functional group. Although the introduction of cyano groups into polymer side chains is expected to improve adhesion with other resins and materials due to dipole-dipole interactions and changes in polarity, there have been only a limited number of reports of PPS with cyano groups in the side chains.

[0005] For example, Patent Document 1 reports a polyarylene thioether copolymer having m repeating units represented by the following formula (C) and n repeating units represented by the following formula (D), in which the value of m / (m+n) is 0.20 to 0.90.

[0006] [ka]

[0007] [ka]

[0008] Furthermore, Patent Document 2 reports the synthesis of a polymer using 2,6-difluorobenzonitrile, 4,4'-thiobisbenzenethiol, 1,4-benzenethiol, and sodium sulfide as monomers.

[0009] Furthermore, Patent Document 3 reports the synthesis of a polymer using 2,6-difluorobenzonitrile and 4,4'-thiobisbenzenethiol as monomers. [Prior art documents] [Patent documents]

[0010] [Patent Document 1] Japanese Patent Application Publication No. 2-28217 [Patent Document 2] Japanese Patent Application Laid-Open No. 2000-269080 [Patent Document 3] Japanese Patent Application Laid-Open No. 2016-109855 Summary of the Invention [Problem to be solved by the invention]

[0011] Although the method described in Patent Document 1 can certainly produce a polymer having a cyano group in the side chain, it is a reaction method in which the raw material components are charged all at once, and there is room for improvement in terms of molecular weight distribution, etc. Furthermore, there is no description about the adhesiveness to other resins or materials.

[0012] The method described in Patent Document 2 requires the use of special monomers such as 4,4'-thiobisbenzenethiol and 1,4-benzenethiol, which poses problems from the viewpoint of industrial production. Furthermore, there is no description about the adhesiveness to other resins or materials.

[0013] Furthermore, the method described in Patent Document 3 also requires the use of a special monomer, 4,4'-thiobisbenzenethiol, which poses a problem from the viewpoint of industrial production. Moreover, there is no description of adhesiveness to other resins or materials. [Means for solving the problem]

[0014] In order to solve the above problems, the present invention employs the following means.

[0015] That is, the present invention is [1] A polyarylene sulfide copolymer having a structure represented by the following formula (A) and a polyarylene sulfide unit as constituent units, and having a weight average molecular weight Mw of more than 10,000 and a molecular weight distribution of 6.0 or less.

[0016] [ka]

[0017] (R is a substituent selected from hydrogen, an alkyl group having 1 to 12 carbon atoms, and an arylene group having 6 to 24 carbon atoms.) [2] A method for producing a polyarylene sulfide copolymer, comprising mixing a polyarylene sulfide prepolymer having a number average molecular weight Mn of 300 or more and 30,000 or less with a nitrile compound represented by the following formula (B), and heating the mixture:

[0018] [ka]

[0019] (R is a substituent selected from hydrogen, an alkyl group having 1 to 12 carbon atoms, and an arylene group having 6 to 24 carbon atoms. X is a halogen group.) [3] A method for producing the polyarylene sulfide copolymer according to [2] above, comprising heating a reaction mixture containing at least a sulfidizing agent, a dihalogenated aromatic compound, and an organic polar solvent as raw material components to obtain a polyarylene sulfide prepolymer having a number average molecular weight Mn of 300 or more and 30,000 or less. DETAILED DESCRIPTION OF THE INVENTION

[0020] An embodiment of the present invention will be described below.

[0021] (1) Polyarylene sulfide copolymer The polyarylene sulfide copolymer in the present invention is a polyarylene sulfide copolymer having a structure represented by the following formula (A) and polyarylene sulfide units as constituent units, and having a weight average molecular weight Mw of more than 10,000 and a molecular weight distribution of 6.0 or less.

[0022] [ka]

[0023] (R is a substituent selected from hydrogen, an alkyl group having 1 to 12 carbon atoms, and an arylene group having 6 to 24 carbon atoms.) Here, the polyarylene sulfide unit is a structure derived from a compound having a repeating unit of the formula -(Ar-S)- as a main constituent unit, and is preferably derived from a linear homopolymer or a linear polyarylene sulfide copolymer containing 80 mol % or more of the repeating unit.

[0024] Here, Ar may be any of the units represented by the following formulae (E) to (N), with formula (E) being particularly preferred.

[0025] [ka]

[0026] (In the formula, R1 and R2 are substituents selected from hydrogen, alkyl groups having 1 to 6 carbon atoms, alkoxy groups having 1 to 6 carbon atoms, and halogen groups, and R1 and R2 may be the same or different.) As long as this repeating unit is the main structural unit, it may contain a small amount of branching units or crosslinking units. The copolymerization amount of these branching units or crosslinking units is preferably in the range of 0 to 1 mol % per 1 mol of the main structural unit represented by -(Ar-S)-.

[0027] Particularly preferred polyarylene sulfide units include p-phenylene sulfide units as the main structural units.

[0028] [ka]

[0029] The content is 80 mol % or more, preferably 90 mol % or more.

[0030] The weight average molecular weight of the polyarylene sulfide copolymer of the present invention is more than 10,000, more preferably 12,000 or more, and even more preferably 14,000 or more.

[0031] Polyarylene sulfide copolymers in this weight-average molecular weight range are generally preferred because they can be used for various applications such as resins, fibers, and films.

[0032] On the other hand, the weight average molecular weight of the polyarylene sulfide copolymer in the present invention is preferably not more than 1,000,000, more preferably not more than 500,000, and even more preferably not more than 100,000. Within such a preferred range, molding processability tends to be excellent.

[0033] The molecular weight distribution of the polyarylene sulfide copolymer of the present invention is 6.0 or less, preferably 5.5 or less, and more preferably 5.0 or less, while the lower limit is preferably 2.0 or more, more preferably 2.2 or more, and even more preferably 2.5 or more.

[0034] The weight average molecular weight (Mw), number average molecular weight (Mn), and molecular weight distribution of the polyarylene sulfide copolymer and polyarylene sulfide prepolymer are values ​​calculated by gel permeation chromatography (GPC) measurement using polystyrene of known molecular weight as a standard substance.

[0035] Here, the ratio of the structure represented by the following formula (A) to the polyarylene sulfide unit in the polyarylene sulfide copolymer can be calculated from the ratio of the polyarylene sulfide prepolymer and the nitrile compound used in producing the polyarylene sulfide copolymer, and the conversion rate of the nitrile compound.

[0036] [ka]

[0037] That is, since the nitrile compound used reacts with the polyarylene sulfide prepolymer and is incorporated into the polyarylene sulfide copolymer, if the conversion rate of the nitrile compound is 100%, it is considered that all of the nitrile compound used is incorporated into the polyarylene sulfide copolymer.

[0038] (2) Nitrile compounds The nitrile compound used in the present invention is a nitrile compound represented by the following formula (B).

[0039] [ka]

[0040] (R is a substituent selected from hydrogen, an alkyl group having 1 to 12 carbon atoms, and an arylene group having 6 to 24 carbon atoms. X is a halogen group.)

[0041] Specific examples thereof include 2,6-dibromobenzonitrile, 2,6-dichlorobenzonitrile, 2,6-difluorobenzonitrile, 2,5-dibromobenzonitrile, 2,5-dichlorobenzonitrile, 2,5-difluorobenzonitrile, 2,4-dibromobenzonitrile, 2,4-dichlorobenzonitrile, and 2,4-difluorobenzonitrile, and among these, 2,6-dichlorobenzonitrile and 2,6-difluorobenzonitrile are preferred.

[0042] (3) Sulfidizing agent The sulfidizing agent used in a preferred embodiment of the present invention may be any agent capable of introducing a sulfide bond into a dihalogenated aromatic compound, and examples thereof include alkali metal sulfides, alkali metal hydrosulfides, and hydrogen sulfide.

[0043] Specific examples of alkali metal sulfides include lithium sulfide, sodium sulfide, potassium sulfide, rubidium sulfide, cesium sulfide, and mixtures of two or more of these. Among these, lithium sulfide and / or sodium sulfide are preferred, with sodium sulfide being more preferred. These alkali metal sulfides can be used as hydrates, aqueous mixtures, or anhydrous forms. An aqueous mixture refers to an aqueous solution, a mixture of an aqueous solution and a solid component, or a mixture of water and a solid component. Generally available, inexpensive alkali metal sulfides are hydrates or aqueous mixtures, so it is preferable to use alkali metal sulfides in these forms.

[0044] 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. Among these, lithium hydrosulfide and / or sodium hydrosulfide are preferred, and sodium hydrosulfide is more preferred.

[0045] Alternatively, an alkali metal sulfide produced in a reaction system from an alkali metal hydrosulfide and an alkali metal hydroxide can be used. Alternatively, an alkali metal sulfide prepared in advance by contacting an alkali metal hydrosulfide with an alkali metal hydroxide can be used. These alkali metal hydrosulfides and alkali metal hydroxides can be used in the form of a compound selected from hydrates, aqueous mixtures, and anhydrides. Hydrates or aqueous mixtures are preferred from the viewpoints of availability and cost.

[0046] Furthermore, alkali metal sulfides produced in a reaction system from an alkali metal hydroxide such as lithium hydroxide or sodium hydroxide and hydrogen sulfide can also be used.Alkali metal sulfides prepared in advance by contacting an alkali metal hydroxide such as lithium hydroxide or sodium hydroxide with hydrogen sulfide can also be used.Hydrogen sulfide may be used in any form, whether gaseous, liquid, or aqueous solution.

[0047] In a preferred embodiment of the present invention, the amount of sulfidizing agent means the remaining amount obtained by subtracting the loss from the actual charged amount when a portion of the sulfidizing agent is lost before the start of the reaction due to a dehydration operation or the like.

[0048] It is also possible to use an alkali metal hydroxide and / or an alkaline earth metal hydroxide together with the sulfidizing agent. Specific examples of alkali metal hydroxides include sodium hydroxide, potassium hydroxide, lithium hydroxide, rubidium hydroxide, cesium hydroxide, and mixtures of two or more of these. Specific examples of alkaline earth metal hydroxides include calcium hydroxide, strontium hydroxide, and barium hydroxide, with sodium hydroxide being preferred.

[0049] When an alkali metal hydrosulfide is used as the sulfidizing agent, it is particularly preferred to use an alkali metal hydroxide simultaneously. In this case, the amount of alkali metal hydroxide used can be 0.95 mol or more, preferably 1.00 mol or more, and more preferably 1.005 mol or more per mol of alkali metal hydrosulfide. It can also be 5.0 mol or less, preferably 4.5 mol or less, and more preferably 4.0 mol or less. When hydrogen sulfide is used as the sulfidizing agent, it is particularly preferred to use an alkali metal hydroxide simultaneously. In this case, the amount of alkali metal hydroxide used can be 2.0 mol or more, preferably 2.01 mol or more, and more preferably 2.04 mol or more per mol of hydrogen sulfide. It can also be 6.0 mol or less, preferably 5.5 mol or less, and more preferably 5.0 mol or less.

[0050] (4) Dihalogenated aromatic compounds The dihalogenated aromatic compound used in a preferred 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 contains one mole of arylene units and two moles of halogeno groups. For example, compounds having a phenylene group, which is a divalent group of a benzene ring, as the arylene group and two halogeno groups include dihalogenated benzenes such as p-dichlorobenzene, o-dichlorobenzene, m-dichlorobenzene, p-dibromobenzene, o-dibromobenzene, m-dibromobenzene, 1-bromo-4-chlorobenzene, and 1-bromo-3-chlorobenzene. Further examples of dihalogenated aromatic compounds include compounds containing substituents other than halogen, such as 1-methoxy-2,5-dichlorobenzene, 1-methyl-2,5-dichlorobenzene, 1,4-dimethyl-2,5-dichlorobenzene, 1,3-dimethyl-2,5-dichlorobenzene, and 3,5-dichlorobenzoic acid. Among these, dihalogenated aromatic compounds containing p-dihalogenated benzene, typified by p-dichlorobenzene, as a main component are preferred, and those containing 80 to 100 mol % of p-dichlorobenzene are particularly preferred, and those containing 90 to 100 mol % of p-dichlorobenzene are even more preferred.

[0051] (5) Organic polar solvents In a preferred embodiment of the present invention, an organic polar solvent is used, with organic amide solvents being particularly preferred. Specific examples include N-alkylpyrrolidones such as N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, and N-cyclohexyl-2-pyrrolidone; caprolactams such as N-methyl-ε-caprolactam; aprotic organic solvents such as 1,3-dimethyl-2-imidazolidinone, N,N-dimethylacetamide, N,N-dimethylformamide, and hexamethylphosphoric triamide; and mixtures thereof, which are preferably used due to their high reaction stability. Among these, N-methyl-2-pyrrolidone and 1,3-dimethyl-2-imidazolidinone are particularly preferred.

[0052] (6) Polyarylene sulfide prepolymer The polyarylene sulfide prepolymer in the present invention is a compound having a number average molecular weight Mn of 300 or more and 30,000 or less, and containing a repeating unit of the formula -(Ar-S)- as a main constituent unit, and is preferably a linear homopolymer or a linear polyarylene sulfide copolymer containing 80 mol % or more of the repeating unit.

[0053] The polyarylene sulfide prepolymer forms a polyarylene sulfide copolymer by reacting its terminal with the halogeno group of the nitrile compound, and the polyarylene sulfide prepolymer is incorporated into the polyarylene sulfide copolymer as a polyarylene sulfide unit.

[0054] Here, examples of Ar include units represented by the following formulae (E) to (N), with formula (E) being preferred.

[0055] [ka]

[0056] (In the formula, R1 and R2 are substituents selected from hydrogen, alkyl groups having 1 to 6 carbon atoms, alkoxy groups having 1 to 6 carbon atoms, and halogen groups, and R1 and R2 may be the same or different.)

[0057] As long as this repeating unit is the main structural unit, it may contain a small amount of branching units or crosslinking units. The copolymerization amount of these branching units or crosslinking units is preferably in the range of 0 to 1 mol % per 1 mol of the main structural unit represented by -(Ar-S)-.

[0058] Particularly preferred polyarylene sulfide prepolymers include those containing p-phenylene sulfide units as the main structural units of the polymer.

[0059] [ka]

[0060] and polyphenylene sulfide prepolymers containing 80 mol % or more, preferably 90 mol % or more of the above.

[0061] Furthermore, the number-average molecular weight of the polyarylene sulfide prepolymer in an embodiment of the present invention is 300 or more and 30,000 or less, more preferably 500 or more and 15,000 or less, and even more preferably 700 or more and 10,000 or less. When the number-average molecular weight of the polyarylene sulfide prepolymer is in the range of less than 300, it is generally difficult to control polymerization, and decomposition reactions and the like tend to occur easily. Furthermore, when the number-average molecular weight of the polyarylene sulfide prepolymer is in the range of more than 30,000, the adhesiveness of the polyarylene sulfide copolymer tends to be difficult to improve.

[0062] When the polyarylene sulfide prepolymer is a low molecular weight compound synthesized by a general organic synthesis reaction, or when it is made up of a substantially pure substance, its molecular weight is treated as a number average molecular weight.

[0063] As will be described later in Section (7), when a polyarylene sulfide prepolymer is synthesized by a method of reacting an alkali metal sulfide with a dihalogenated aromatic compound in an organic amide solvent, the terminals of the polyarylene sulfide prepolymer vary depending on the molar balance between the sulfidating agent and the dihalogenated aromatic compound during synthesis, and when an excess of the sulfidating agent is used relative to the dihalogenated aromatic compound, the polyarylene sulfide prepolymer tends to have thiolate terminals.

[0064] When a polyarylene sulfide copolymer is synthesized by reacting a polyarylene sulfide prepolymer with a nitrile compound represented by the following formula (B), the polyarylene sulfide prepolymer preferably has 50% or more, and more preferably 70% or more, of the terminals thereof as thiolate terminals relative to the total number of terminals of the polyarylene sulfide prepolymer. By using a polyarylene sulfide prepolymer having such a terminal structure, the molecular weight of the polyarylene sulfide copolymer tends to be improved.

[0065] [ka]

[0066] (7) Method for producing polyarylene sulfide prepolymer The method for producing the polyarylene sulfide prepolymer used in the present invention is not particularly limited as long as it can synthesize a polyarylene sulfide prepolymer that satisfies the requirement (6) above, and any method can be used. For example, a method in which an alkali metal sulfide and a dihalogenated aromatic compound are reacted in an organic amide solvent can be preferably used.

[0067] When producing a polyarylene sulfide prepolymer having a thiolate end, it is preferable to use less than 1 mole of a dihalogenated aromatic compound per mole of a sulfidizing agent, more preferably 0.97 moles or less, and even more preferably 0.95 moles or less. As a lower limit, it is preferable to use 0.1 moles or more of a dihalogenated aromatic compound per mole of a sulfidizing agent, more preferably 0.15 moles or more, and even more preferably 0.2 moles or more. By doing so, it is possible to control the molecular weight of the polyarylene sulfide prepolymer to an appropriate level.

[0068] There is no particular limitation on the amount of organic polar solvent used in the present production method, but from the viewpoints of stable reactivity and economy, it is preferably 0.25 L or more per mole of sulfidizing agent, with the upper limit being preferably less than 5.0 L, more preferably less than 1.0 L, and even more preferably less than 0.8 L, for example.

[0069] The reaction temperature when reacting an alkali metal sulfide with a dihalogenated aromatic compound in an organic polar solvent cannot be uniquely determined because it varies depending on the type and amount of the organic polar solvent. However, the lower limit is typically 120°C or higher, preferably 180°C or higher, more preferably 200°C or higher, and even more preferably 210°C or higher. This preferred temperature range allows for a higher reaction rate and shorter reaction times. On the other hand, the upper limit is typically 260°C or lower, preferably 250°C or lower, and more preferably 240°C or lower. By conducting the reaction within this preferred temperature range, side reactions due to overheating can be suppressed, and the resulting polyarylene sulfide prepolymer is more easily dissolved, which tends to result in a uniform and easy-to-progress reaction. The reaction may be a single-stage reaction carried out at a constant temperature, a multi-stage reaction in which the temperature is increased stepwise, or a reaction in which the temperature is changed continuously.

[0070] The reaction time cannot be generally determined because it depends on the type and amount of raw materials used and the reaction temperature, but is preferably 0.1 hours or more, more preferably 0.5 hours or more. By setting the reaction time at this preferred time or longer, unreacted raw material components can be reduced. On the other hand, there is no particular upper limit to the reaction time, but the reaction proceeds sufficiently within 40 hours, and preferably within 10 hours, more preferably within 6 hours.

[0071] The sulfidizing agent can be used in the form of a hydrate or aqueous mixture, but in this case, it is preferable to carry out a dehydration step in which a mixture containing an organic polar solvent and a sulfidizing agent is heated and excess water is removed from the system before adding a dihalogenated aromatic compound. There are no particular limitations on the dehydration method, but a desirable method is to add an alkali metal hydrosulfide and an alkali metal hydroxide to an organic polar solvent under an inert gas atmosphere at a temperature ranging from room temperature to 150°C, preferably from room temperature to 100°C, and then heat the mixture to at least 150°C or higher, preferably 180 to 260°C, under atmospheric pressure or reduced pressure, to distill off the water.

[0072] When an alkali metal sulfide and a dihalogenated aromatic compound are reacted in an organic polar solvent to produce a polyarylene sulfide prepolymer, the conversion of the sulfidizing agent is preferably 30% or more, more preferably 40% or more, and even more preferably 50% or more. The conversion of the dihalogenated aromatic compound is preferably 50% or more, more preferably 60% or more, and even more preferably 70% or more. There is no upper limit to the conversion of the alkali metal sulfide and the dihalogenated aromatic compound, and a higher conversion is preferable.

[0073] The reaction can be carried out in any of various known polymerization and reaction methods, such as a batch method, a continuous method, etc. The production is preferably carried out in a non-oxidizing atmosphere, preferably in an inert gas atmosphere such as nitrogen, helium, or argon, and preferably in a nitrogen atmosphere from the standpoints of economy and ease of handling.

[0074] The conversion rate of the dihalogenated aromatic compound is a value calculated by the following formula: The remaining amount of the dihalogenated aromatic compound can usually be determined by gas chromatography. Conversion rate (%) = [charged amount of dihalogenated aromatic compound (mol) - remaining amount of dihalogenated aromatic compound (mol)] / [charged amount of dihalogenated aromatic compound (mol)] × 100 The conversion rate of the sulfidizing agent is a value calculated from the following formula. Conversion rate (%) = [charged amount of sulfidizing agent (mol) - remaining amount of sulfidizing agent (mol)] / [charged amount of sulfidizing agent (mol)] × 100

[0075] Here, the remaining amount of sulfidizing agent can be measured by ion chromatography (IC).

[0076] (8) Method for producing polyarylene sulfide copolymer In the present invention, a polyarylene sulfide prepolymer having a number average molecular weight Mn of 300 or more and 30,000 or less is mixed with a nitrile compound represented by the following formula (B), and the mixture is heated to produce a polyarylene sulfide copolymer.

[0077] [ka]

[0078] (R is a substituent selected from hydrogen, an alkyl group having 1 to 12 carbon atoms, and an arylene group having 6 to 24 carbon atoms. X is a halogen group.)

[0079] In this production method, the polyarylene sulfide prepolymer and the nitrile compound can be mixed in an organic polar solvent, but the organic polar solvent is preferably an organic amide solvent, specific examples of which include N-alkylpyrrolidones such as N-methyl-2-pyrrolidone and N-ethyl-2-pyrrolidone, aprotic organic solvents such as 1,3-dimethyl-2-imidazolidinone and N,N-dimethylacetamide, and mixtures thereof, with N-methyl-2-pyrrolidone and 1,3-dimethyl-2-imidazolidinone being particularly preferred.

[0080] The reaction temperature in this production method cannot be uniquely determined because it varies depending on the type and amount of organic polar solvent. However, the lower limit is typically 120°C or higher, preferably 150°C or higher, more preferably 180°C or higher, and even more preferably 200°C or higher. This preferred temperature range allows for a higher reaction rate and a shorter reaction time. On the other hand, the upper limit is typically 280°C or lower, preferably 260°C or lower, more preferably 240°C or lower, and even more preferably 230°C or lower. The reaction may be a one-stage reaction carried out at a constant temperature, a multi-stage reaction in which the temperature is increased in stages, or a reaction in which the temperature is changed continuously.

[0081] The method for adding the polyarylene sulfide prepolymer and the nitrile compound to react with each other is not particularly limited, and known methods can be employed. For example, there can be mentioned a method of mixing previously prepared reaction solutions at room temperature and further heating, a method of adding a nitrile compound at room temperature to a heated polyarylene sulfide prepolymer solution and further heating, and a method of adding a heated nitrile compound solution to a heated polyarylene sulfide prepolymer synthesized in advance.

[0082] In this production method, the reaction is preferably carried out until the conversion rate of the nitrile compound reaches 50% or more, more preferably 70% or more, and even more preferably 80% or more.

[0083] Here, the nitrile compound used reacts with the polyarylene sulfide prepolymer and is incorporated into the polyarylene sulfide copolymer. Therefore, if the conversion rate of the nitrile compound is 100%, it is considered that all of the nitrile compound used has been incorporated into the polyarylene sulfide copolymer.

[0084] Therefore, the composition ratio of the polyarylene sulfide unit to the nitrile unit in the polyarylene sulfide copolymer can be calculated from the ratio of the polyarylene sulfide prepolymer to the nitrile compound used and the conversion rate of the nitrile compound.

[0085] Furthermore, when a polyarylene sulfide prepolymer is synthesized by heating a reaction mixture containing at least a sulfidizing agent, a dihalogenated aromatic compound, and an organic polar solvent as raw material components, the conversion rate of the sulfidizing agent derived from the synthesis of the polyarylene sulfide prepolymer is preferably 50% or more, more preferably 60% or more, and even more preferably 70% or more.

[0086] In such a state, the reaction between the polyarylene sulfide prepolymer and the nitrile compound tends to proceed efficiently, and the molecular weight and properties of the polyarylene sulfide copolymer tend to be improved.

[0087] The conversion rate of the nitrile compound is a value calculated by the following formula: The remaining amount of the nitrile compound can usually be determined by gas chromatography. Conversion rate (%) = [charged amount of nitrile compound (mol) - remaining amount of nitrile compound (mol)] / [charged amount of nitrile compound (mol)] × 100

[0088] Furthermore, when a polyarylene sulfide prepolymer is synthesized by heating a reaction mixture containing at least a sulfidizing agent, a dihalogenated aromatic compound, and an organic polar solvent as raw material components, the ratio of the amount of the nitrile compound to the amount of the dihalogenated aromatic compound used is preferably more than 0.01 mol, more preferably 0.03 mol or more, and even more preferably 0.05 mol or more, per mol of the dihalogenated aromatic compound, from the viewpoint of simultaneously achieving various properties of the polyarylene sulfide copolymer. On the other hand, the upper limit is preferably 5.0 mol or less, more preferably 3.0 mol or less, and even more preferably 2.0 mol or less, per mol of the dihalogenated aromatic compound. The amount of the dihalogenated aromatic compound used is the sum of the amount used during the synthesis of the polyarylene sulfide prepolymer and, if added during the synthesis of the polyarylene sulfide copolymer, the amount used during the synthesis of the polyarylene sulfide, and the amount of the nitrile compound is the amount used during the synthesis of the polyarylene sulfide copolymer.

[0089] (9) Method for recovering polyarylene sulfide copolymer In the production of the polyarylene sulfide copolymer of the present invention, it is also possible to separate and recover the polyarylene sulfide copolymer from the reaction mixture obtained by the above-mentioned reaction. The reaction mixture obtained by the reaction contains the polyarylene sulfide copolymer and the organic polar solvent, and may also contain other components such as unreacted sulfidizing agent, dihalogenated aromatic compound, nitrile compound, water, by-product salts, etc.

[0090] There are no particular limitations on the method for recovering the polyarylene sulfide copolymer from the reaction mixture, and an example thereof is a method in which, if necessary, a part or most of the organic polar solvent is removed by an operation such as distillation, and then the polyarylene sulfide copolymer is recovered by contacting the polyarylene sulfide copolymer with a solvent that has low solubility in the polyarylene sulfide copolymer, is miscible with the organic polar solvent, and preferably has solubility in the by-product salt, under heating if necessary. By performing treatment with such a solvent, it is possible to reduce the amounts of the organic polar solvent and the by-product salt contained in the mixed solid of the polyarylene sulfide copolymer.

[0091] Solvents having the above-described properties are generally solvents with relatively high polarity, and the preferred solvent varies depending on the type of organic polar solvent and by-product salt used and cannot be limited, but examples thereof include water, alcohols, ketones, and acetate esters. From the viewpoints of availability and economy, water, methanol, and acetone are preferred, and water is particularly preferred.

[0092] When water is used as the solvent, it is preferable that the water is distilled water or deionized water. However, if necessary, it is also possible to use an aqueous solution containing an organic acidic compound such as acetic acid or propionic acid, or an alkali metal salt or alkaline earth metal salt thereof, or an inorganic acidic compound such as sulfuric acid or hydrochloric acid, or ammonium ions.

[0093] This treatment causes the polyarylene sulfide copolymer to precipitate as a solid component, and the polyarylene sulfide copolymer can be recovered using a known solid-liquid separation method. Examples of solid-liquid separation methods include separation by filtration, centrifugation, decantation, etc. This series of treatments can be repeated several times as necessary, which tends to further reduce the amounts of organic polar solvents and by-product salts contained in the mixed solid of the polyarylene sulfide copolymer.

[0094] If the polyarylene sulfide copolymer mixed solid obtained after this treatment contains the solvent used in the treatment, it is possible to remove the solvent by drying or the like as necessary. Here, it is desirable to remove at least 50% by weight, preferably 70% by weight or more, more preferably 90% by weight or more, and even more preferably 95% by weight or more of the solvent. The temperature at which the solvent is removed by heating depends on the properties of the solvent used and cannot be uniquely defined, but can usually be selected from the range of 20 to 150°C, preferably 40 to 120°C. Furthermore, the pressure at which the solvent is removed is preferably atmospheric pressure or less, which allows the solvent to be removed at a lower temperature.

[0095] (10) Uses of polyarylene sulfide copolymer The polyarylene sulfide copolymer obtained by the present invention is excellent in heat resistance, chemical resistance, flame retardancy, electrical properties, and mechanical properties, and can be used not only for injection molding, injection compression molding, and blow molding, but also for extrusion molding into extrusion molded products such as sheets, films, fibers, and pipes. In this case, the polyarylene sulfide copolymer may be used alone, or, if desired, inorganic fillers such as glass fiber, carbon fiber, titanium oxide, and calcium carbonate, antioxidants, heat stabilizers, ultraviolet absorbers, colorants, etc. may be added, and resins other than the polyarylene sulfide copolymer of the present invention may also be blended.

[0096] PPS, a representative PAS, generally has a simple main chain skeleton primarily composed of benzene rings and sulfur atoms and lacks functional groups, leaving room for improvement in its adhesive strength with other resins and materials. However, the polyarylene sulfide copolymer of the present invention has polar functional groups in its side chains, which gives it excellent adhesive strength with other resins and materials, such as epoxy resins, glass fiber, and carbon fiber. Generally, the closer the solubility parameters (SP values) between a resin and an adhesive, the stronger the adhesion. However, the polyarylene sulfide copolymer obtained by the present invention can adjust the SP value of the polyarylene sulfide copolymer by adjusting the copolymerization amount of the nitrile compound, which is expected to improve adhesive strength with a variety of adhesives.

[0097] Furthermore, the polyarylene sulfide copolymer having nitrile groups obtained by the present invention can also be converted into a polymer electret by post-treating it using a method such as that described in a patent document (JP-A No. 2000-269080).

[0098] Examples of applications include electrical and electronic components, sensor components, home and office electrical appliance parts, optical equipment and precision machinery related parts, plumbing parts, automotive and vehicle related parts, and other industrial applications. [Example]

[0099] The present invention will be described in more detail below with reference to examples, which are illustrative and not limiting.

[0100] [Conversion rate measurement of dihalogenated aromatic compounds and nitrile compounds] The conversion rates of dihalogenated aromatic compounds and nitrile compounds were quantitatively analyzed by gas chromatography (GC) under the following GC measurement conditions: Equipment: Shimadzu GC-2010 Column: Agilent Technologies DB-5 0.32 mm x 30 m (0.25 μm) Carrier gas: Helium Detector: Flame ionization detector (FID).

[0101] [Measurement of sulfidizing agent conversion rate] The conversion rate of the sulfidizing agent was calculated by quantitative analysis using ion chromatography (IC). Equipment: Shimadzu HIC-20Asuper Column: Shimadzu Shim-pack IC-SA2 (250 mm x 4.6 mm ID) Detector: Electrical conductivity detector (suppressor) Eluent: 4.0 mM sodium bicarbonate / 1.0 mM sodium carbonate aqueous solution Flow rate: 1.0ml / min Injection volume: 50 microliters Column temperature: 30℃

[0102] Hydrogen peroxide was added to the sample to oxidize the sulfide ions contained in the sample, and then the amount was quantified as sulfate ions using the above analysis. The amount of sulfide ions calculated here was taken as the amount of unreacted sulfidizing agent, and the conversion rate of the sulfidizing agent was calculated from the ratio to the amount of sulfidizing agent charged. The calculation formula is as follows: Conversion rate (%)=[charged amount of sulfidizing agent (mol)−remaining amount of sulfidizing agent (mol)] / [charged amount of sulfidizing agent (mol)]×100.

[0103] [Molecular weight measurement] The molecular weight and molecular weight distribution of the polyarylene sulfide copolymer and polyarylene sulfide prepolymer were calculated in terms of polystyrene by gel permeation chromatography (GPC), a type of size exclusion chromatography (SEC). The GPC measurement conditions are shown below. Equipment: Senshu Science SSC-7100 Column name: Shodex UT-806M Eluent: 1-chloronaphthalene Detector: Differential refractive index detector Column temperature: 210℃ Pre-thermostat temperature: 250℃ Pump thermostatic bath temperature: 50℃ Detector temperature: 210℃ Flow rate: 1.0mL / min Sample injection volume: 300 μL (slurry: approximately 0.2 wt %).

[0104] [Peel test] Equipment: Imada Co., Ltd. test stand MX-500N, digital force gauge ZTA-500N Test piece: Aluminum foil, polymer sample, spacer, and Kapton (registered trademark) film were placed between the molds of a press machine set at melting point + 20°C, and a pressure of approximately 30 kgf / cm was applied. 2The sample was heated under pressure and then rapidly cooled to form a polymer sample film (approximately 100 μm thick) on the aluminum foil. The sample was cut into a size of 18 mm wide x 300 mm long and used for testing. Test: The edges of the aluminum foil and polymer sample film were set in the tester, and a peel test was performed at a take-up speed of 30 mm / min. The force required to peel the aluminum foil and polymer sample film was measured.

[0105] [Example 1] <Polyphenylene sulfide prepolymer synthesis process> A 1-liter autoclave equipped with a stirrer was charged with 58.40 g (0.50 mol of sodium hydrosulfide) of a 48 wt% aqueous solution of sodium hydrosulfide, 43.10 g (0.52 mol of sodium hydroxide) of a 48 wt% aqueous solution of sodium hydroxide, and 82.00 g of N-methyl-2-pyrrolidone (NMP). The mixture was gradually heated to 240°C over approximately 3 hours under atmospheric pressure with nitrogen flow. Heating was stopped and cooling commenced when 51 g of water and 1 g of NMP had distilled out. Furthermore, the amount of hydrogen sulfide released was 0.0075 mol, meaning that the amount of sulfidizing agent in the system after this step was 0.49 mol.

[0106] The mixture was then cooled to below 200°C, and 65.10 g (0.443 mol) of p-dichlorobenzene (p-DCB) and 170 g of NMP were added. The reaction vessel was then sealed under nitrogen gas, and the temperature was raised to 230°C at a rate of 1°C / min while stirring at 400 rpm, and the reaction was carried out at 230°C for 4 hours. The molar ratio of p-DCB to sodium hydrosulfide at this time was p-DCB / sodium hydrosulfide = 90 / 100, and the amount of NMP was 0.5 liters per mole of sulfur component.

[0107] <Polyphenylene sulfide copolymer synthesis process> After the PPS prepolymer synthesis step was completed, the reaction solution was cooled to 210°C, and a solution of 8.60 g (0.050 mol) of 2,6-dichlorobenzonitrile (DCBN) dissolved in 85 g of NMP was injected into the autoclave.

[0108] Thereafter, the mixture was reacted for 60 minutes at 210° C. The molar ratio of DCBN to the p-DCB used in the previous step and sodium hydrosulfide was DCBN / p-DCB / sodium hydrosulfide=10 / 90 / 100, and the amount of NMP was 0.67 L per mole of the sulfur component.

[0109] After the reaction was completed, the internal temperature was cooled to about room temperature, and the contents were recovered.

[0110] The resulting contents, i.e., the reaction mixture, was analyzed by gas chromatography, and it was found that the conversion of the monomer p-DCB was 98% and the conversion of DCBN was 100%.

[0111] <Recovery process> 100 g of the resulting mixture was diluted with approximately 300 g of a 0.5 wt% aqueous acetic acid solution and then filtered through a glass filter with an average mesh size of 10 to 16 micrometers. The filtered-on component was dispersed in approximately 100 g of ion-exchanged water, stirred at 80°C for 15 minutes, and then filtered again in the same manner as above, a total of three times to obtain a solid. This was then vacuum-dried at 100°C overnight to obtain a dry solid.

[0112] As a result of the analysis, peaks due to cyano groups and phenylene sulfide skeletons were observed in the absorption spectrum of infrared spectroscopy, confirming that this was the target polyphenylene sulfide copolymer. The weight-average molecular weight of the obtained polyphenylene sulfide copolymer was 15,000, and the molecular weight distribution was 4.0. The polyphenylene sulfide copolymer obtained here is referred to as polyphenylene sulfide copolymer 1.

[0113] By comparing with the results of Comparative Example 1, it was found that by reacting polyphenylene sulfide prepolymer with DCBN, a polyphenylene sulfide copolymer with a higher molecular weight could be obtained.

[0114] [Reference example 1] Here, an example will be described in which a PPS prepolymer was synthesized by the method of Example 1 and evaluated.

[0115] After reaction at 230°C for 4 hours in the same manner as in the PPS prepolymer synthesis step of Example 1, the internal temperature was cooled to near room temperature and the contents were recovered. Analysis of the obtained contents by GC showed that the conversion of p-DCB was 98% and the conversion of sodium hydrosulfide was 93%.

[0116] The solid was recovered in the same manner as in Example 1. Analysis revealed that the solid was PPS from the absorption spectrum in infrared spectroscopy. The weight-average molecular weight was 3,900 and the number-average molecular weight was 2,000.

[0117] [Example 2] <Polyphenylene sulfide prepolymer synthesis process> A 1-liter autoclave equipped with a stirrer was charged with 58.40 g (0.50 mol of sodium hydrosulfide) of a 48 wt% aqueous solution of sodium hydrosulfide, 43.10 g (0.52 mol of sodium hydroxide) of a 48 wt% aqueous solution of sodium hydroxide, and 82.00 g of NMP. The mixture was gradually heated to 240°C over approximately 3 hours under atmospheric pressure while passing nitrogen through it. Heating was stopped and cooling commenced when 51 g of water and 1 g of NMP had been distilled. Furthermore, the amount of hydrogen sulfide released was 0.0075 mol, so the amount of sulfidizing agent in the system after this step was 0.49 mol.

[0118] The mixture was then cooled to below 200°C, and 48.20 g (0.328 mol) of p-DCB and 170 g of NMP were added. The reaction vessel was then sealed under nitrogen gas, and the temperature was raised to 220°C at a rate of 1°C / min while stirring at 400 rpm, and the reaction was carried out at 220°C for 6 hours. The molar ratio of p-DCB to sodium hydrosulfide at this time was p-DCB / sodium hydrosulfide = 67 / 100, and the amount of NMP was 0.5 liters per mole of sulfur component.

[0119] <Polyphenylene sulfide copolymer synthesis process> After the PPS prepolymer synthesis step was completed, the reaction solution was cooled to 210°C, and a solution of 28.40 g (0.165 mol) of DCBN dissolved in 85 g of NMP was injected into the autoclave.

[0120] Thereafter, the mixture was reacted for 60 minutes at 210° C. The molar ratio of DCBN to the p-DCB used in the previous step and sodium hydrosulfide was DCBN / p-DCB / sodium hydrosulfide=33 / 67 / 100, and the amount of NMP was 0.67 liters per mole of the sulfur component.

[0121] After the reaction was completed, the internal temperature was cooled to about room temperature, and the contents were recovered.

[0122] The resulting contents, i.e., the reaction mixture, was analyzed by gas chromatography, and it was found that the conversion of the monomer p-DCB was 98% and the conversion of DCBN was 100%.

[0123] <Recovery process> The solid was recovered in the same manner as in the recovery step of Example 1. As a result of analysis, peaks based on cyano groups and phenylene sulfide skeletons were observed in the absorption spectrum in infrared spectroscopy, and it was confirmed that the solid was a polyphenylene sulfide copolymer.

[0124] The weight average molecular weight of the resulting polyphenylene sulfide copolymer was 12,000, and the molecular weight distribution was 4.1.

[0125] [Reference example 2] Here, an example will be described in which a PPS prepolymer was synthesized by the method of Example 2 and evaluated.

[0126] After reaction at 220°C for 6 hours in the same manner as in the PPS prepolymer synthesis step of Example 2, the internal temperature was cooled to near room temperature and the contents were recovered. Analysis of the obtained contents by GC showed that the conversion of p-DCB was 98% and the conversion of sodium hydrosulfide was 82%.

[0127] The solid was recovered in the same manner as in Example 1. Analysis revealed that the solid was PPS from the absorption spectrum in infrared spectroscopy. The weight-average molecular weight was 1,400 and the number-average molecular weight was 900.

[0128] [Comparative Example 1] Here, an example is shown in which raw material components were charged all at once so that the molar ratio of DCBN / p-DCB / sodium hydrosulfide was 10 / 90 / 100, and polyphenylene sulfide copolymer was synthesized.

[0129] <Polyphenylene sulfide copolymer synthesis process> A 1-liter autoclave equipped with a stirrer was charged with 58.40 g (0.50 mol of sodium hydrosulfide) of a 48 wt% aqueous solution of sodium hydrosulfide, 43.10 g (0.52 mol of sodium hydroxide) of a 48 wt% aqueous solution of sodium hydroxide, and 82.00 g of NMP. The mixture was gradually heated to 240°C over approximately 3 hours under atmospheric pressure while passing nitrogen through it. Heating was stopped and cooling commenced when 51 g of water and 1 g of NMP had been distilled. Furthermore, the amount of hydrogen sulfide released was 0.0075 mol, so the amount of sulfidizing agent in the system after this step was 0.49 mol.

[0130] Thereafter, the mixture was cooled to 200°C or below, and 65.10 g (0.443 mol) of p-DCB, 8.60 g (0.050 mol) of DCBN, and 255 g of NMP were added. The reaction vessel was then sealed under nitrogen gas, and the temperature was raised to 250°C at a rate of 1°C / min while stirring at 400 rpm, and the reaction was carried out at 250°C for 3 hours.

[0131] At this time, the molar ratio of each component was DCBN / p-DCB / sodium hydrosulfide=10 / 90 / 100, and the amount of NMP was 0.67 liters per mole of the sulfur component.

[0132] After the reaction was completed, the internal temperature was cooled to about room temperature, and the contents were recovered.

[0133] The resulting contents, i.e., the reaction mixture, was analyzed by gas chromatography, and it was found that the conversion of the monomer p-DCB was 97% and the conversion of DCBN was 100%.

[0134] <Recovery process> The solid was recovered in the same manner as in the recovery step of Example 1. As a result of analysis, peaks based on cyano groups and phenylene sulfide skeletons were observed in the absorption spectrum of infrared spectroscopy, confirming that the solid was a polyphenylene sulfide copolymer. The weight-average molecular weight of the resulting polyphenylene sulfide copolymer was 7,000, and the molecular weight distribution was 3.0.

[0135] Comparative Example 2 Here, an example is shown in which raw material components were charged all at once so that the molar ratio of DCBN / p-DCB / sodium hydrosulfide was 33 / 67 / 100, and polyphenylene sulfide copolymer was synthesized.

[0136] <Polyphenylene sulfide copolymer synthesis process> A 1-liter autoclave equipped with a stirrer was charged with 58.40 g (0.50 mol of sodium hydrosulfide) of a 48 wt% aqueous solution of sodium hydrosulfide, 43.10 g (0.52 mol of sodium hydroxide) of a 48 wt% aqueous solution of sodium hydroxide, and 82.00 g of NMP. The mixture was gradually heated to 240°C over approximately 3 hours under atmospheric pressure while passing nitrogen through it. Heating was stopped and cooling commenced when 51 g of water and 1 g of NMP had been distilled. Furthermore, the amount of hydrogen sulfide released was 0.0075 mol, so the amount of sulfidizing agent in the system after this step was 0.49 mol.

[0137] Thereafter, the mixture was cooled to 200°C or below, and 48.20 g (0.33 mol) of p-DCB, 28.40 g (0.17 mol) of DCBN, and 251 g of NMP were added. The reaction vessel was then sealed under nitrogen gas, and the temperature was raised to 250°C at a rate of 1°C / min while stirring at 400 rpm, and the reaction was carried out at 250°C for 3 hours.

[0138] At this time, the molar ratio of each component was DCBN / p-DCB / sodium hydrosulfide=33 / 67 / 100, and the amount of NMP was 0.67 liters per mole of the sulfur component.

[0139] After the reaction was completed, the internal temperature was cooled to about room temperature, and the contents were recovered.

[0140] The resulting contents, i.e., the reaction mixture, was analyzed by gas chromatography, and it was found that the conversion of the monomer p-DCB was 97% and the conversion of DCBN was 100%.

[0141] <Recovery process> The solid was recovered in the same manner as in the recovery step of Example 1. As a result of analysis, peaks based on cyano groups and phenylene sulfide skeletons were observed in the absorption spectrum of infrared spectroscopy, confirming that the solid was a polyphenylene sulfide copolymer. The weight-average molecular weight of the resulting polyphenylene sulfide copolymer was 6,000, and the molecular weight distribution was 6.1.

[0142] [Reference example 3] In this reference example, the adhesive strength between polyphenylene sulfide copolymer 1 and aluminum foil was evaluated by a peel test.

[0143] A press film of polyphenylene sulfide copolymer 1 was formed on an aluminum foil, and the force required to peel the aluminum foil from the polyphenylene sulfide copolymer 1 film was measured and found to be 1.3 Newtons.

[0144] [Reference example 4] In this reference example, the adhesive strength between PPS and aluminum foil was evaluated by a peel test.

[0145] A press film of PPS (Toray Industries, Inc.'s "Torelina" M2588) was created on aluminum foil, and the force required to peel the aluminum foil from the PPS film was measured, resulting in a value of 1.1 Newtons.

Claims

1. A polyarylene sulfide copolymer having a structure represented by the following formula (A) and polyarylene sulfide units as constituent units, and having a weight average molecular weight Mw of more than 10,000 and a molecular weight distribution of 6.0 or less, wherein the polyarylene sulfide copolymer contains five or more structures represented by formula (A): 【Chemical 1】 (R is a substituent selected from hydrogen, an alkyl group having 1 to 12 carbon atoms, and an arylene group having 6 to 24 carbon atoms.)

2. A method for producing a polyarylene sulfide copolymer, comprising mixing a polyarylene sulfide prepolymer having a number average molecular weight Mn of 300 or more and 2,000 or less with a nitrile compound represented by the following formula (B), and heating the mixture: 【Chemistry 2】 (R is a substituent selected from hydrogen, an alkyl group having 1 to 12 carbon atoms, and an arylene group having 6 to 24 carbon atoms. X is a halogen group.)

3. 3. A method for producing the polyarylene sulfide copolymer according to claim 2, comprising heating a reaction mixture containing at least a sulfidizing agent, a dihalogenated aromatic compound, and an organic polar solvent as raw material components to obtain the polyarylene sulfide prepolymer having a number average molecular weight Mn of 300 or more and 2,000 or less.

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