WO2024116564A1

WO2024116564A1 - Polyarylene sulfide resin composition and method for producing molded article

Info

Publication number: WO2024116564A1
Application number: PCT/JP2023/034212
Authority: WO
Inventors: 拓茨木; 啓介山田; 繁明永野
Original assignee: Dic株式会社
Priority date: 2022-11-29
Filing date: 2023-09-21
Publication date: 2024-06-06

Abstract

The present invention provides a method for producing a PAS resin composition having excellent electrical conductivity by highly dispersing carbon nanotubes (CNT) in a polyarylene sulfide (PAS) resin. The present invention more specifically provides a method for producing a PAS resin composition wherein CNT are dispersed in a PAS resin, the method comprising a step (1) for obtaining a mixture (A) by mixing a PAS resin, a CNT dispersion liquid, an organic polar solvent and a dispersing assistant, a step (2) for stirring the mixture (A) at 200°C or higher, and a step (3) for cooling the mixture (A), wherein: the CNT dispersion liquid contains at least CNT and an organic polar solvent and/or water; and the hydrogen bonding term (dH) in the Hansen solubility parameter of the dispersing assistant is 1 to 10 (MPa0.5).

Description

Polyarylene sulfide resin composition and method for producing molded article

The present invention relates to a polyarylene sulfide resin composition and a method for producing a molded article.

Polyarylene sulfide resins (hereafter abbreviated as PAS resins), such as polyphenylene sulfide resins (hereafter abbreviated as PPS resins), are widely used in fields such as automotive parts and electrical and electronic equipment because they have excellent heat resistance, mechanical strength, chemical resistance, moldability, and dimensional stability.

On the other hand, PPS resin has the property of low electrical conductivity, and to improve this, resin compositions containing conductive fillers such as carbon black and carbon fiber have been developed. However, as the range of uses for PPS resin expands, the required electrical conductivity performance increases year by year, and in order to impart sufficient electrical conductivity to the resin composition, it has become necessary to highly fill the resin with conductive filler. This high filler filling causes the inherent mechanical properties and molding processability of PPS resin to be impaired, which has been an issue.

As a method to solve this problem, the use of carbon nanotubes (hereafter abbreviated as CNT), which can impart high conductivity with the addition of a small amount, is being considered. For example, a manufacturing method has been considered in which CNT is highly dispersed in PAS resin by polymerizing the PAS resin in the presence of CNT (e.g., Patent Documents 1 and 2, etc.). However, the degree of polymerization of the PAS resin obtained with this manufacturing method is low, so there are limitations on the processing conditions and applications.

Furthermore, for resins that are soluble in organic solvents in the presence of CNTs, a method has been proposed in which the resin is completely dissolved in an organic solvent before being mixed to highly disperse the CNTs in the resin (e.g., Patent Document 3, etc.), but there is still room for improvement in the dispersibility of CNTs in PAS resin using this method.

JP 2005-232247 A JP 2007-507562 A JP 2010-242091 A

The problem that the present invention aims to solve is to provide a method for producing a PAS resin composition with excellent electrical conductivity by highly dispersing CNTs in the PAS resin.

After extensive investigation, the inventors discovered that by mixing PAS resin, a CNT dispersion, an organic polar solvent, and a dispersion aid, and then heating and stirring the resulting mixture and then cooling it, a PAS resin composition in which CNTs are highly dispersed in the PAS resin can be obtained, which led to the completion of the present invention.

That is, the present disclosure provides a method for producing a PAS resin composition in which CNTs are dispersed in a PAS resin, comprising:
A step (1) of mixing a PAS resin, a CNT dispersion, an organic polar solvent, and a dispersion aid to obtain a mixture (A);
Step (2) of stirring the mixture (A) at 200° C. or higher;
(3) cooling the mixture (A),
The CNT dispersion contains at least CNTs and an organic polar solvent and/or water,
The present invention relates to a method for producing a PAS resin composition, wherein the hydrogen bond term (dH) in the Hansen solubility parameters of the dispersion aid is 1 to 10 [MPa ^0.5 ].

The present disclosure also provides a method for producing a PAS resin composition, comprising a step of melt-kneading the PAS resin composition obtained by the above-described production method with a PAS resin,
The present invention relates to a method for producing a PAS resin composition, in which the CNT content per 100 parts by mass of the obtained PAS resin composition is 1.0 part by mass or less, and the volume resistivity is 1.0×10 ¹⁰ Ω·cm or less.

The present invention provides a method for producing a PAS resin composition with excellent electrical conductivity by highly dispersing CNTs in the PAS resin.

The following describes in detail an embodiment of the present invention, but the scope of the present invention is not limited to the embodiment described here, and various modifications can be made without departing from the spirit of the present invention. Furthermore, when multiple upper and lower limit values are listed for a specific parameter, any of these upper and lower limit values can be combined to create a suitable numerical range.

First Embodiment
The method for producing a PAS resin composition according to the first embodiment of the present disclosure includes a step (1) of mixing a PAS resin, a CNT dispersion, an organic polar solvent, and a dispersion aid to obtain a mixture (A), a step (2) of stirring the mixture (A) at 200° C. or higher, and a step (3) of cooling the mixture (A). The steps are described in detail below.

<Step (1)>
Step (1) is a step of mixing a PAS resin, a CNT dispersion, an organic polar solvent, and a dispersion aid to obtain a mixture (A). The obtained mixture (A) contains at least the PAS resin, the CNT dispersion, the organic polar solvent, and the dispersion aid.

The PAS resin that can be used in this embodiment has a resin structure with a repeating unit in which an aromatic ring and a sulfur atom are bonded, specifically, the following general formula (1)

(wherein R ¹ and R ² each independently represent a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, a nitro group, an amino group, a phenyl group, a methoxy group, or an ethoxy group), and, if necessary, a structural portion represented by the following general formula (2):

The trifunctional structural unit represented by formula (2) is preferably in the range of 0.001 to 3 mol %, particularly preferably 0.01 to 1 mol %, based on the total number of moles of the trifunctional structural unit and other structural units.

Here, the structural portion represented by the general formula (1), particularly ^R1 and ^R2 in the formula, are preferably hydrogen atoms from the viewpoint of the mechanical strength of the PAS resin. In this case, examples of the structural portion include those bonded at the para position represented by the following formula (3) and those bonded at the meta position represented by the following formula (4).

Among these, a structure in which the bond between the sulfur atom and the aromatic ring in the repeating unit is bonded at the para position represented by the general formula (3) is particularly preferred in terms of heat resistance and crystallinity of the PAS resin.

The PAS resin has structural moieties represented by the general formulas (1) and (2) above, as well as the following structural formulas (5) to (8):

The structural moiety represented by the general formula (1) and the structural moiety represented by the general formula (2) may be contained in an amount of 30 mol % or less of the total of the structural moieties represented by the general formula (1) and the general formula (2). In particular, in the present invention, it is preferable that the structural moieties represented by the general formulas (5) to (8) are 10 mol % or less in terms of the heat resistance and mechanical strength of the PAS resin. When the structural moieties represented by the general formulas (5) to (8) are contained in the PAS resin, the bonding mode thereof may be either a random copolymer or a block copolymer.

The PAS resin may also have naphthyl sulfide bonds in its molecular structure, but this is preferably 3 mol % or less, and more preferably 1 mol % or less, relative to the total number of moles including other structural parts.

The physical properties of the PAS resin are not particularly limited as long as they do not impair the effects of the present invention, but are as follows:

(Melt Viscosity)
The melt viscosity of the PAS resin used in this embodiment is not particularly limited, but in order to obtain a good balance between fluidity and mechanical strength, the melt viscosity (V6) measured at 300°C is preferably in the range of 1 Pa·s or more, and preferably in the range of 1000 Pa·s or less, more preferably in the range of 500 Pa·s or less, and even more preferably in the range of 200 Pa·s or less. However, the melt viscosity (V6) is measured by using a Shimadzu flow tester, CFT-500D, and is the measured value of the melt viscosity after holding the PAS resin at 300°C, load: 1.96×10 ⁶ Pa, L/D=10 (mm)/1 (mm) for 6 minutes.

(Non-Newtonian Exponents)
The non-Newtonian index of the PAS resin used in this embodiment is not particularly limited, but is preferably in the range of 0.90 to 2.00. However, in the present invention, the non-Newtonian index (N value) is a value calculated using the following formula by measuring the shear rate (SR) and shear stress (SS) using a capillograph under the conditions of melting point +20°C and the ratio of the orifice length (L) to the orifice diameter (D) L/D=40. The closer the non-Newtonian index (N value) is to 1, the closer the structure is to a linear structure, and the higher the non-Newtonian index (N value), the more branched the structure is.

[where SR is the shear rate (sec ^-1 ), SS is the shear stress (dynes/ ^cm2 ), and K is a constant.]

(Production method)
The method for producing the PAS resin is not particularly limited, but examples thereof include (production method 1) a method in which a dihalogeno aromatic compound is polymerized in the presence of sulfur and sodium carbonate, and if necessary, a polyhalogeno aromatic compound or other copolymerization component is added, (production method 2) a method in which a dihalogeno aromatic compound is polymerized in the presence of a sulfidizing agent or the like in a polar solvent, and if necessary, a polyhalogeno aromatic compound or other copolymerization component is added, (production method 3) a method in which p-chlorothiophenol is added, and if necessary, other copolymerization components are added, and self-condensed, and (production method 4) a method in which a diiodo aromatic compound and elemental sulfur are melt-polymerized under reduced pressure in the presence of a polymerization inhibitor that may have a functional group such as a carboxy group or an amino group. Among these methods, (production method 2) is preferred because it is versatile. During the reaction, an alkali metal salt of a carboxylic acid or sulfonic acid or an alkali hydroxide may be added to adjust the degree of polymerization. Among the above-mentioned (Production Method 2) methods, there is a method for producing a PAS resin by introducing a water-containing sulfidizing agent into a mixture containing a heated organic polar solvent and a dihalogeno aromatic compound at a rate at which water can be removed from the reaction mixture, and reacting the dihalogeno aromatic compound and the sulfidizing agent in the organic polar solvent, and optionally adding a polyhalogeno aromatic compound, and controlling the amount of water in the reaction system to within a range of 0.02 to 0.5 mol per mol of the organic polar solvent (see JP-A-07-228699). Particularly preferred is a method in which a dihalogeno-aromatic compound and, if necessary, a polyhalogeno-aromatic compound or other copolymerization component are added in the presence of an alkali metal sulfide and an aprotic polar organic solvent, and an alkali metal hydrosulfide and an organic acid alkali metal salt are reacted while controlling the organic acid alkali metal salt in the range of 0.01 to 0.9 mol per mol of the sulfur source and the amount of water in the reaction system to be 0.02 mol or less per mol of the aprotic polar organic solvent (see WO2010/058713 pamphlet). Specific examples of the dihalogeno aromatic compound include p-dihalobenzene, m-dihalobenzene, o-dihalobenzene, 2,5-dihalotoluene, 1,4-dihalonaphthalene, 1-methoxy-2,5-dihalobenzene, 4,4'-dihalobiphenyl, 3,5-dihalobenzoic acid, 2,4-dihalobenzoic acid, 2,5-dihalonitrobenzene, 2,4-dihalonitrobenzene, 2,4-dihaloanisole, p,p'-dihalodiphenyl ether, 4,4'-dihalobenzophenone, 4,4'-di Examples of the polyhalogeno aromatic compounds include 1,2,3-trihalobenzene, 1,2,4-trihalobenzene, 1,3,5-trihalobenzene, 1,2,3,5-tetrahalobenzene, 1,2,4,5-tetrahalobenzene, 1,4,6-trihalonaphthalene, etc. The halogen atoms contained in the above compounds are preferably chlorine atoms or bromine atoms.

　The method of post-treatment of the reaction mixture containing the PAS resin obtained by the polymerization step is not particularly limited, but for example, (post-treatment 1) after the polymerization reaction is completed, first, the reaction mixture is left as is or after adding an acid or base, and the solvent is distilled off under reduced pressure or normal pressure, and then the solid matter remaining after the solvent distillation is washed once or twice or more times with a solvent such as water, the reaction solvent (or an organic solvent having a similar solubility to the low molecular weight polymer), acetone, methyl ethyl ketone, alcohols, etc., and then neutralized, washed with water, filtered and dried, or (post-treatment 2) after the polymerization reaction is completed, the reaction mixture is dissolved in a solvent such as water, acetone, methyl ethyl ketone, alcohols, ethers, halogenated hydrocarbons, aromatic hydrocarbons, aliphatic hydrocarbons, etc. (a solvent that is soluble in the polymerization solvent used and is a poor solvent for at least the PAS resin). (a solvent having a solubility of about 100% or less) is added as a precipitant to precipitate solid products such as PAS resin and inorganic salts, which are then filtered, washed with water, and dried; or (post-treatment 3) after the polymerization reaction is completed, a reaction solvent (or an organic solvent having a solubility equivalent to that of the low molecular weight polymer) is added to the reaction mixture, the mixture is stirred, filtered to remove the low molecular weight polymer, and the mixture is washed once or twice with a solvent such as water, acetone, methyl ethyl ketone, or alcohols, and then neutralized, washed with water, filtered, and dried; (post-treatment 4) after the polymerization reaction is completed, water is added to the reaction mixture, the mixture is washed with water, filtered, and if necessary, an acid or base is added during the water washing, and the mixture is dried; (post-treatment 5) after the polymerization reaction is completed, the reaction mixture is filtered, and if necessary, the mixture is washed once or twice or more with the reaction solvent, and then washed with water, filtered, and dried.

In the post-treatment methods exemplified above in (Post-treatment 1) to (Post-treatment 5), the PAS resin may be dried in a vacuum, in air, or in an inert gas atmosphere such as nitrogen.

The PAS resin used in this embodiment may be a recycled PAS resin. When the PAS resin used in this embodiment contains the recycled material, the proportion of the recycled material in the resin is not particularly limited, but is preferably 50% by mass or less, more preferably 40% by mass or less, and even more preferably 30% by mass or less. The processing (recycling process) of PAS resin molded products into recycled materials can be carried out by a known method. For example, a method of dividing the molded product into chips or pellets by cutting or crushing, a method of dissolving the divided molded product in a solvent and then performing solid-liquid separation to remove fillers, and a method of contacting the divided molded product with a solvent to extract and remove components other than PAS resin. Recycling processes are often carried out based on collected PAS resin molded products provided by consumers, out-of-spec PAS resin molded products provided by molded product manufacturers, and losses generated during molding (such as runners in injection molding). By using recycled PAS resin, the amount of waste resin and molded products can be reduced, thereby reducing the environmental load.

CNT dispersions applicable to this embodiment contain at least CNT and an organic polar solvent and/or water. In this disclosure, a dispersion refers to one in which CNT is dispersed in an organic polar solvent and/or water, and moreover, in this disclosure, it is preferable that the CNT is dispersed without forming aggregates.

CNTs have a cylindrical shape formed by rolling up one surface of graphite. Examples of CNTs include single-walled nanotubes (SWNTs) with a structure of one layer rolled up, and multi-walled nanotubes (MWNTs) with two or more layers rolled up. Any of these can be used in the present invention. Among these, SWNTs with a diameter of 20 nm or less are preferred from the viewpoint of exhibiting conductivity with a smaller amount of addition, and those that form bundles with a bundle diameter of 1 μm or less are preferred, and those that form bundles of 100 nm or less are even more preferred. Furthermore, from the viewpoint of facilitating the formation of conductive paths in the PAS resin, those with a length of 100 nm or more are preferred. Furthermore, CNTs can generally be manufactured by laser ablation, arc thermal CVD, plasma CVD, gas phase, combustion, etc., but CNTs manufactured by any method can be used.

The surface and ends of the CNT used in this embodiment may be modified with functional groups to increase affinity with resins, for example, functionalized with hydroxyl groups, carboxyl groups, or amino groups using an acid or alkali, as long as this does not impair the effects of the present invention. Furthermore, the CNT may be pre-treated with a coupling agent before use, and examples of such coupling agents include isocyanate compounds, organic silane compounds, organic titanate compounds, and epoxy compounds.

The organic polar solvent contained in the CNT dispersion liquid used in this embodiment is not particularly limited, but from the viewpoint of affinity, it is preferable to use an organic polar solvent similar to the organic polar solvent mixed with the PAS resin in this process. Furthermore, the content of the organic polar solvent and/or water in the CNT dispersion liquid is preferably 10 parts by mass or more and 500 parts by mass or less per 100 parts by mass of the CNT dispersion liquid. Within this range, the CNTs can maintain an optimal bundle diameter for imparting electrical conductivity.

The amount of CNT dispersion liquid added is not particularly limited, but from the viewpoint of highly dispersing CNT in the PAS resin while suppressing aggregation, it is preferable to adjust the amount of CNT to 20 parts by mass or less, and more preferably to 5 parts by mass or less, per 100 parts by mass of PAS resin contained in the mixture (A). It is also preferable that the amount is 0.05 parts by mass or more. If the CNT content is too low, a conductive path is not formed in the resin composition, making it difficult to exhibit excellent conductive properties. On the other hand, if the CNT content is too high, material costs will increase, and there may be an increase in viscosity and a decrease in physical properties due to an increase in the interface between the CNT and the resin in the resin composition.

Organic polar solvents that can be used in this embodiment include, for example, amides, ureas, and lactams such as formamide, acetamide, N-methylformamide, N,N-dimethylacetamide, tetramethylurea, N-methyl-2-pyrrolidone, 2-pyrrolidone, N-methyl-ε-caprolactam, ε-caprolactam, hexamethylphosphoramide, N-dimethylpropyleneurea, and 1,3-dimethyl-2-imidazolidinoic acid; sulfolanes such as sulfolane and dimethylsulfolane; nitriles such as benzonitrile; ketones such as methylphenylketone, and mixtures thereof. Among these, amides having an aliphatic cyclic structure such as N-methyl-2-pyrrolidone, 2-pyrrolidone, N-methyl-ε-caprolactam, ε-caprolactam, hexamethylphosphoramide, N-dimethylpropyleneurea, and 1,3-dimethyl-2-imidazolidinoic acid are preferred, and N-methyl-2-pyrrolidone is even more preferred.

The amount of organic polar solvent added is not particularly limited, but is preferably 150 parts by mass or more, more preferably 300 parts by mass or more, and preferably 2000 parts by mass or less, and more preferably 1000 parts by mass or less, relative to 100 parts by mass of the PAS resin contained in the mixture (A). Within this range, the CNTs are highly dispersed in the PAS resin dissolved in the organic polar solvent.

The dispersion aid that can be applied to this embodiment is not particularly limited as long as it does not impair the effects of the present invention, and any known dispersion aid having a hydrogen bond term (dH) in the Hansen solubility parameter of 1 to 10 [MPa ^0.5 ] can be used. For example, water-soluble resins such as polyvinylidene fluoride (PVDF), polyvinylpyrrolidone (PVP), and polythiophene (PT) can be mentioned. By using a dispersion aid, the affinity between CNT and PAS resin can be improved, so that the added CNT can exhibit functions (electrical conductivity and thermal conductivity) with a smaller amount. Note that the hydrogen bond term (dH) in the Hansen solubility parameter in this disclosure is a value calculated by the atomic group contribution method based on the chemical structure using Hansen Solubility Parameter Software (HSPiP).

The amount of the dispersion aid added is preferably 10 parts by mass or more, more preferably 50 parts by mass or more, even more preferably 100 parts by mass or more, and preferably 500 parts by mass or less, and more preferably 400 parts by mass or less, relative to 100 parts by mass of CNT contained in the mixture (A). Within this range, the affinity between the CNT and the resin can be efficiently improved. The dispersion aid may also be mixed in advance with the CNT dispersion liquid or the organic polar solvent before use.

<Step (2)>
The step (2) is a step of stirring the mixture (A) at 200° C. or higher.

In this step, the method of heating and stirring the mixture (A) is not particularly limited, and known methods and devices can be used. The heating conditions may be either an open system or a closed system, and are not particularly limited, but heating in a closed system is preferred from the viewpoint of improving productivity.

The temperature range of mixture (A) is from 200°C or higher, preferably from 220°C or higher to 270°C or lower, in terms of the solubility of the PAS resin in the organic polar solvent. By stirring within this range, the PAS resin and the CNT dispersion can be entangled on a molecular chain scale, and good dispersibility can be exhibited. The processing time in this step is not particularly limited as long as it does not impair the effects of the present invention, and it is preferable to stir at 200°C or higher until the PAS resin dissolves in the organic polar solvent, the molecular chains of the PAS resin are sufficiently entangled with the CNTs, and the stirring torque stabilizes.

<Step (3)>
The step (3) is a step of cooling the mixture (A).

In this step, the method for cooling the mixture (A) is not particularly limited, and known methods and devices can be used. The cooling conditions may be either an open system or a closed system, and are not particularly limited, but cooling in a closed system is preferred from the viewpoint of improving productivity.

The cooling temperature for cooling the mixture (A) is not particularly limited as long as it does not impair the effects of the present invention, but for example, a rate of 2°C/min or more is preferable, and 5°C/min or more is more preferable. Furthermore, the temperature of the mixture (A) after cooling is preferably 150°C or less, and more preferably 60°C or less. Within this range, productivity is high, and the molecular chains of the PAS resin and the CNTs can be removed from the reaction vessel in a well-entangled state.

The cooled mixture (A) is recovered, and then the solid-liquid separation is performed. The solid phase component can be dried as is and used as a PAS resin composition powder, or it can be washed with warm water, hot water, carbonated water, etc., and then subjected to solid-liquid separation and drying to prepare a powdered or granular PAS resin composition.

The PAS resin composition obtained by the method for producing a PAS resin composition according to the present embodiment has a structure in which CNTs are highly dispersed in the PAS resin, and therefore exhibits excellent electrical conductivity. The electrical conductivity of the PAS resin composition in the present disclosure is not particularly limited, but for example, the volume resistivity is 1.0×10 ¹⁰ [Ω·cm] or less. The volume resistivity is a value measured by the method in the examples.

Second Embodiment
The method for producing a PAS resin composition according to the second embodiment of the present disclosure is a method for producing a PAS resin composition comprising a step of melt-kneading the PAS resin composition obtained by the above-described method with a PAS resin. In other words, the method for producing a PAS resin composition is a method for producing a PAS resin composition in which the PAS resin composition obtained by the above-described method is used as a master batch and further diluted with a PAS resin.

The PAS resin for dilution that can be applied to this embodiment (hereinafter sometimes abbreviated as diluted PAS resin) can be the same as the PAS resin used in step (1) in the first embodiment. The physical properties of the diluted PAS resin are not particularly limited as long as they do not impair the effects of the present invention, and can be selected according to the processing conditions and applications of the PAS resin composition obtained after melt kneading.

The method for producing the PAS resin composition of this embodiment includes a step of blending the essential components and melt-kneading them at a temperature range equal to or higher than the melting point of the PAS resin. More specifically, the PAS resin composition of this embodiment is composed of the essential components and, as necessary, the optional components described below. The method for producing the resin composition used in the present invention is not particularly limited, but includes a method of blending the essential components and, as necessary, the optional components, and melt-kneading them, and more specifically, a method of uniformly dry-mixing them in a tumbler or Henschel mixer, as necessary, and then feeding them into a twin-screw extruder and melt-kneading them.

The melt kneading can be carried out by heating the resin to a temperature range in which the resin temperature is equal to or higher than the melting point of the PAS resin, preferably equal to or higher than said melting point + 10°C, more preferably equal to or higher than said melting point + 10°C, even more preferably equal to or higher than said melting point + 20°C, preferably equal to or lower than said melting point + 100°C, more preferably equal to or lower than said melting point + 50°C.

The melt kneader is preferably a twin-screw kneading extruder from the viewpoint of dispersibility and productivity. For example, it is preferable to melt knead while appropriately adjusting the resin component discharge rate in the range of 5 to 500 (kg/hr) and the screw rotation speed in the range of 50 to 500 (rpm), and it is even more preferable to melt knead under conditions where the ratio (discharge rate/screw rotation speed) is in the range of 0.02 to 5 (kg/hr/rpm). In addition, the addition and mixing of each component to the melt kneader may be performed simultaneously or in portions. For example, when adding a fibrous filler or the like as an optional component, it is preferable from the viewpoint of dispersibility to feed the extruder from a side feeder of the twin-screw kneading extruder. The position of the side feeder is preferably such that the ratio of the distance from the extruder resin input section (top feeder) to the side feeder to the total screw length of the twin-screw kneading extruder is 0.1 or more, and more preferably 0.3 or more. In addition, such a ratio is preferably 0.9 or less, and more preferably 0.7 or less.

In this embodiment, the blending ratio of the diluted PAS resin to the PAS resin composition is preferably adjusted so that the CNT content of the PAS resin composition obtained after melt kneading is 0.05 to 1.0 parts by mass per 100 parts by mass of PAS resin. In this range, the resulting PAS resin composition exhibits excellent electrical conductivity and mechanical strength.

In the method for producing a PAS resin composition according to this embodiment, a filler can be blended as an optional component, if necessary. As these fillers, well-known and commonly used materials can be used as long as they do not impair the effects of the present invention, and examples include fillers of various shapes, such as granular, plate-like, and fibrous fillers. For example, fillers such as glass fiber, carbon fiber, aramid fiber, glass beads, glass flakes, barium sulfate, clay, pyrophyllite, bentonite, sericite, mica, talc, attapulgite, ferrite, calcium silicate, calcium carbonate, magnesium carbonate, zeolite, milled fiber, and calcium sulfate can also be used.

In the method for producing the PAS resin composition according to this embodiment, a silane coupling agent can be blended as an optional component, if necessary. There are no particular limitations on the silane coupling agent as long as it does not impair the effects of the present invention, but preferred examples include silane coupling agents having a functional group that reacts with a carboxy group, such as an epoxy group, an isocyanato group, an amino group, or a hydroxyl group. Examples of such silane coupling agents include epoxy group-containing alkoxysilane compounds such as γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropyltriethoxysilane, and β-(3,4-epoxycyclohexyl)ethyltrimethoxysilane; isocyanato group-containing alkoxysilane compounds such as γ-isocyanatopropyltrimethoxysilane, γ-isocyanatopropyltriethoxysilane, γ-isocyanatopropylmethyldimethoxysilane, γ-isocyanatopropylmethyldiethoxysilane, γ-isocyanatopropylethyldimethoxysilane, γ-isocyanatopropylethyldiethoxysilane, and γ-isocyanatopropyltrichlorosilane; amino group-containing alkoxysilane compounds such as γ-(2-aminoethyl)aminopropylmethyldimethoxysilane, γ-(2-aminoethyl)aminopropyltrimethoxysilane, and γ-aminopropyltrimethoxysilane; and hydroxyl group-containing alkoxysilane compounds such as γ-hydroxypropyltrimethoxysilane and γ-hydroxypropyltriethoxysilane.

In addition to the above components, the method for producing the PAS resin composition according to this embodiment can further include optional synthetic resins (hereinafter simply referred to as synthetic resins) such as polyester resin, polyamide resin, polyimide resin, polyetherimide resin, polycarbonate resin, polyphenylene ether resin, polysulfone resin, polyphenylene sulfide sulfone resin, polyethersulfone resin, polyetheretherketone resin, polyetherketone resin, polyarylene resin, polyethylene resin, polypropylene resin, polytetrafluoroethylene resin, polyethylenedifluoroethylene resin, polystyrene resin, ABS resin, phenolic resin, urethane resin, liquid crystal polymer, and thermoplastic elastomer, as appropriate, depending on the application.

In the method for producing the PAS resin composition according to this embodiment, other known and commonly used additives such as colorants, antistatic agents, antioxidants, heat stabilizers, UV stabilizers, UV absorbers, foaming agents, flame retardants, flame retardant assistants, rust inhibitors, and release agents (metal salts or esters of fatty acids having 18 to 30 carbon atoms, including stearic acid or montanic acid, polyolefin waxes such as polyethylene, etc.) can be blended as optional components as necessary. These additives are not essential components, and may be used in an amount of, for example, preferably 0.01 parts by mass or more relative to 100 parts by mass of PAS resin, and preferably 1000 parts by mass or less, more preferably 100 parts by mass or less, and even more preferably 10 parts by mass or less, depending on the purpose and application so as not to impair the effects of the present invention.

In addition, the method for producing a PAS resin composition according to this embodiment provides a PAS resin composition with excellent electrical conductivity. Specifically, the volume resistivity is 1.0×10 ¹⁰ Ω·cm or less. The volume resistivity is a value measured by the method of the example. The volume resistivity is a value measured by the method of the example.

The PAS resin composition and PAS resin molded article obtained by the above manufacturing method contain PAS resin, CNT, and a dispersing aid as essential components, and may contain the optional components listed above. The resin composition and molded article have a morphology in which the PAS resin forms a continuous phase and the CNT and optional components are dispersed. By having the PAS resin composition have such a morphology, molded articles can be obtained that have excellent thermal conductivity and electrical conductivity while retaining the heat resistance and chemical resistance of PAS resin.

The PAS resin composition disclosed herein can be subjected to various molding processes such as injection molding, compression molding, extrusion molding of composites, sheets, pipes, etc., pultrusion molding, blow molding, and transfer molding, but is particularly suitable for injection molding. When molding by injection molding, the various molding conditions are not particularly limited, and molding can be performed by a normal general method. For example, in an injection molding machine, the PAS resin composition is melted at a resin temperature in a temperature range of the melting point of the PAS resin or higher, preferably in a temperature range of the melting point + 10°C or higher, more preferably in a temperature range of the melting point + 10°C to the melting point + 100°C, and even more preferably in a temperature range of the melting point + 20°C to the melting point + 50°C, and then the resin is injected into a mold from a resin outlet and molded. At that time, the mold temperature may be set to a known temperature range, for example, room temperature (23°C) to 300°C, preferably 130 to 190°C.

The manufacturing method of the molded product disclosed herein may include a step of annealing the molded product. The optimum conditions for the annealing treatment are selected depending on the application or shape of the molded product, and the annealing temperature is in a temperature range equal to or higher than the glass transition temperature of the PAS resin, preferably in a temperature range equal to or higher than the glass transition temperature + 10°C, and more preferably in a temperature range equal to or higher than the glass transition temperature + 30°C. On the other hand, it is preferable that the annealing temperature is in a range of 260°C or lower, and more preferably in a range of 240°C or lower. The annealing time is not particularly limited, but is preferably in a range of 0.5 hours or higher, and more preferably in a range of 1 hour or higher. On the other hand, it is preferable that the annealing time is in a range of 10 hours or lower, and more preferably in a range of 8 hours or lower. In such a range, the distortion of the molded product obtained is reduced and the crystallinity of the resin is improved, which is preferable. The annealing treatment may be performed in air, but is preferably performed in an inert gas such as nitrogen gas.

The uses of the PAS resin molded products disclosed herein are not particularly limited and can be used in a variety of products, but since they are characterized by excellent electrical conductivity in addition to the inherent chemical resistance of PAS resin, they are particularly suitable for use in parts that require chemical resistance and antistatic properties, such as fuels (the term fuel includes fossil fuels such as crude oil, shale oil, shale gas, LNG, gasoline, kerosene, diesel, heavy oil, etc., saturated hydrocarbons such as n-hexane, isohexane, n-nonane, isononane, dodecane, isododecane, 1-hexene, 1-hexane, etc.). The hydrocarbons may be one or more of unsaturated hydrocarbons such as cyclohexane, cycloheptane, cyclooctane, cyclodecane, decalin, etc., cyclic unsaturated hydrocarbons such as cyclohexene, cycloheptene, cyclooctene, 1,1,3,5,7-cyclooctatetraene, cyclododecene, etc., and aromatic hydrocarbons such as benzene, toluene, xylene, etc. The hydrocarbons may be one or more of unsaturated hydrocarbons such as cyclohexane ... In addition, the PAS resin molded article of the present disclosure can also be suitably used for containers that come into contact with or are immersed in inks or paints containing the above-mentioned hydrocarbons, for example, printing parts and painting parts used in printing equipment such as nozzles, brushes, cartridges, pumps, transfer bodies, and transfer belts, sliding parts exemplified by gears that come into contact with lubricating oil, and parts of cleaning equipment such as brushes, hoses, and nozzles used in cleaning using hydrocarbons as a solvent. Furthermore, in addition to the above, the PAS resin molded article can also be made into the following ordinary resin molded articles. For example, electrical and electronic components such as protective and supporting members for box-shaped integrated modules of electrical and electronic components, multiple individual semiconductors or modules, sensors, LED lamps, connectors, sockets, resistors, relay cases, switches, coil bobbins, capacitors, variable capacitor cases, optical pickups, oscillators, various terminal boards, transformers, plugs, printed circuit boards, tuners, speakers, microphones, headphones, small motors, magnetic head bases, power modules, terminal blocks, semiconductors, liquid crystal, FDD carriages, FDD chassis, motor brush holders, parabolic antennas, computer-related components, etc.; VTR components, television components, irons, hair dryers, rice cooker components, microwave oven components, sound Home and office electrical appliance parts such as resonator parts, audio/visual equipment parts such as audio/laser discs, compact discs, DVD discs, and Blu-ray discs, lighting parts, refrigerator parts, air conditioner parts, typewriter parts, word processor parts, and water-related equipment parts such as water heaters, bath water volume and temperature sensors; office computer related parts, telephone related parts, facsimile related parts, copier related parts, cleaning jigs, motor parts, lighters, typewriters, and other machine related parts; optical equipment and precision machinery related parts such as microscopes, binoculars, cameras, and clocks; alternator terminals, alternator connectors, brush holders, slip rings, I C regulators, potentiometer bases for light dimmers, relay blocks, inhibitor switches, various valves such as exhaust gas valves, various pipes for fuel, exhaust systems and intake systems, air intake nozzle snorkels, intake manifolds, engine coolant joints, carburetor main bodies, carburetor spacers, exhaust gas sensors, coolant sensors, oil temperature sensors, brake pad wear sensors, throttle position sensors, crankshaft position sensors, temperature sensors, air flow meters, brake pad wear sensors, thermostat bases for air conditioners, heating hot air flow control valves, brush holders for radiator motors, water Examples of automobile and vehicle-related parts include pump impellers, turbine vanes, wiper motor-related parts, distributors, starter switches, ignition coils and their bobbins, motor insulators, motor rotors, motor cores, starter relays, transmission wire harnesses, windshield washer nozzles, air conditioner panel switch boards, coils for fuel-related electromagnetic valves, fuse connectors, horn terminals, electrical component insulating plates, step motor rotors, lamp sockets, lamp reflectors, lamp housings, brake pistons, solenoid bobbins, engine oil filters, ignition device cases, and other various other applications.

The following examples and comparative examples are used to explain the present invention, but the present invention is not limited to these examples. In the following, unless otherwise specified, "%" and "parts" are based on mass.

Example 1-1: Mixing process of PPS and CNT dispersion
A mixture was obtained by mixing 30 g of PPS resin (linear type, melt viscosity (V6) 106 Pa·s), 60 g of CNT dispersion (0.4% of OCSiAl's TUBALL (registered trademark) powdered SWCNT (product name: TUBALL 01RW03), 1% of polyvinylidene fluoride (PVDF) as a dispersing agent, and N-methylpyrrolidone (NMP) as a solvent), and NMP adjusted so that the solvent ratio to PPS was 5.

<Example 1-2 Stirring step at 200°C or higher>
The above mixture was placed in a 500 mL autoclave equipped with a pressure gauge, a thermometer, and a stirring blade, and the atmosphere was replaced with nitrogen. The autoclave was then sealed and heated to 240° C. and stirred at 240° C. and 300 rpm for 1 hour.

<Example 1-3 Cooling and purification process>
The 240 ° C autoclave was cooled to 150 ° C at 5 ° C / min while stirring, and the stirring speed was reduced to 100 rpm and further cooled to 40 ° C at 5 ° C / min. The obtained black cake-like mixture was mixed uniformly in a mortar, and then the slurry was weighed out so that the PPS resin was 20 g, and 200 g of 70 ° C hot water was added to obtain a reslurry, which was stirred for 10 minutes. While suction filtering the mixture, 200 g of 70 ° C hot water was poured in three times to wash the cake. This reslurry and cake washing operation with hot water was performed three times in total, and the obtained cake was dried at 120 ° C for 4 hours to obtain a PPS resin composition (1) with a CNT content of 0.8%.

Example 2
A PPS resin composition (2) having a CNT content of 0.8% was obtained in the same manner as in Example 1, except that the dispersing aid was changed from PVDF to polyvinylpyrrolidone (PVP).

Example 3
A PPS resin composition (3) having a CNT content of 0.1% was obtained in the same manner as in Example 2, except that the amount of the CNT dispersion was changed from 60 g to 7.5 g.

<Example 4-1>
A PPS resin composition (4-1) having a CNT content of 5% was obtained in the same manner as in Example 2, except that the amount of PPS resin was changed from 30 g to 10 g and the amount of CNT dispersion was changed from 60 g to 125 g.

<Example 4-2>
0.5 g of the obtained PPS resin composition (4-1) and 24.5 g of PPS resin (linear type, melt viscosity (V6) 106 Pa s) were blended, melt-kneaded using a Labo Plastomill at 310°C for 10 minutes, and diluted to obtain a PPS resin composition (4-2) with a CNT content of 0.1%.

<Comparative Example 1>
A PPS resin composition (C1) was obtained in the same manner as in Example 1, except that the amount of the CNT dispersion liquid added was changed from 60 g to 0 g.

<Comparative Example 2>
A PPS resin composition (C2) having a CNT content of 0.8% was obtained in the same manner as in Example 1, except that the dispersing aid was changed from PVDF to polyvinyl alcohol (PVA).
<Comparative Example 3>
A PPS resin composition (C3) having a CNT content of 0.8% was obtained in the same manner as in Example 1, except that the dispersing aid was changed from 1% to 0% PVDF.

<Comparative Example 4>
220.5g (1.5 mol) of p-dichlorobenzene (p-DCB), 39.7g (0.30 mol) of NMP, 186.9g (1.5 mol) of 45% NaSH, and 125.0g (1.5 mol) of 48% NaOH were charged into a 1L autoclave equipped with a stirring blade and a bottom valve, to which a pressure gauge, a thermometer, a condenser, and a decanter were connected, and the temperature was raised to 173°C under a nitrogen atmosphere while stirring. After 167.8g of water was distilled out, the kettle was sealed. At that time, the p-DCB distilled by azeotropy was separated in the decanter and returned to the kettle as needed. After completion of dehydration, the temperature inside the autoclave was cooled to 160° C., and 324.6 g of the same CNT dispersion liquid as that used in Example 1-1 and 132.6 g of NMP were added, and the temperature was then raised to 220° C. and stirred for 2 hours, and then the temperature was raised to 250° C. and stirred for 1 hour, thereby polymerizing the PPS resin in the presence of CNT. The CNT-containing PAS resin crude product after polymerization was cooled to 40° C. and taken out in a slurry state.

The obtained crude product was weighed out so that the PPS resin was 20 g in slurry, and the slurry was heated to 150°C under vacuum while stirring, and NMP was removed over 5 hours. After that, it was cooled to room temperature, and 200 g of 70°C hot water was added to reslurry, and stirred for 10 minutes. The mixture was suction filtered, and 200 g of 70°C hot water was poured in three times to wash the cake. After repeating the reslurry and cake washing three times, the obtained cake and 200 g of water were charged into a 500 ml autoclave and washed with hot water at 230°C for 1 hour. After the hot water washing, the mixture was cooled to room temperature, and 200 g of 70°C hot water was poured in three times while suction filtering to wash the cake. The obtained cake was dried at 120°C for 4 hours to obtain PPS resin composition (C4).

＜Evaluation＞

(1) Evaluation of Electrical Conductivity Electrical conductivity was evaluated from the volume resistivity of the resin composition obtained in each Example and Comparative Example. The volume resistivity was measured using "Loresta AX MCP-T370" (upper limit of measurement: 10 ⁶ Ω·cm) manufactured by Nitto Seiko Analytech Co., Ltd., under conditions of room temperature of 21°C and humidity of 67 RH%, in accordance with JIS K 7194 "Test method for resistivity of conductive plastics by four-probe method". The test pieces were made by pressing the resin compositions obtained in each Example and Comparative Example at 310°C for 2 minutes and molding them into a plate shape (50 mm x 50 mm x 2 mmt). The results are shown in Tables 1 and 2. The resin composition of Comparative Example 1 exceeded the upper limit of measurement by the instrument, so it was described as O.L.

(2) Measurement of Melt Viscosity (V6) The melt viscosity (V6) of the resin compositions obtained in each of the Examples and Comparative Examples was measured using a Shimadzu Corporation flow tester "CFT-500D" under the conditions of 300°C, load: 1.96 x ¹⁰⁶ Pa, L/D = 10 (mm)/1 (mm) after holding for 6 minutes. The results are shown in Tables 1 and 2.

Comparing Examples 1-4 and Comparative Example 1 from Tables 1 and 2, it was shown that CNTs were highly dispersed in the resin compositions obtained in the Examples, and that adding a small amount of CNTs achieved a reduction in volume resistivity. Comparing Examples 1-4 and Comparative Examples 2 and 3, it was confirmed that a reduction in volume resistivity could be achieved by selecting an appropriate dispersing agent. Comparing Examples 1-4 and Comparative Example 4 further showed that the resin compositions of the Examples showed a higher melt viscosity at the same CNT content, and were superior in processability and mechanical strength.

Claims

A method for producing a polyarylene sulfide resin composition in which carbon nanotubes are dispersed in a polyarylene sulfide resin, comprising the steps of:
A step (1) of mixing a polyarylene sulfide resin, a carbon nanotube dispersion, an organic polar solvent, and a dispersion aid to obtain a mixture (A);
Step (2) of stirring the mixture (A) at 200° C. or higher;
(3) cooling the mixture (A),
the carbon nanotube dispersion liquid contains at least carbon nanotubes and an organic polar solvent and/or water,
The method for producing a polyarylene sulfide resin composition, wherein the hydrogen bond term (dH) in the Hansen solubility parameters of the dispersing aid is 1 to 10 [MPa 0.5 ].
(Note that the hydrogen bond term (dH) is a value calculated by the atomic group contribution method using the Hansen Solubility Parameter software (HSPiP).)
The method for producing a polyarylene sulfide resin composition according to claim 1, wherein the content of the carbon nanotubes in 100 parts by mass of the resulting polyarylene sulfide resin composition is 20 parts by mass or less.
3. The method for producing a polyarylene sulfide resin composition according to claim 1 or 2, wherein the volume resistivity of the obtained polyarylene sulfide resin composition is 1.0×10 10 Ω·cm or less.
A method for producing a polyarylene sulfide resin composition, comprising a step of melt-kneading the polyarylene sulfide resin composition obtained by the method for producing a polyarylene sulfide resin according to claim 1 or 2 with a polyarylene sulfide resin,
The method for producing a polyarylene sulfide resin composition, wherein the content of the carbon nanotubes in 100 parts by mass of the obtained polyarylene sulfide resin composition is 1.0 part by mass or less, and the volume resistivity is 1.0×10 10 Ω·cm or less.
A method for producing a polyarylene sulfide resin molded product, comprising a step of melt molding the polyarylene sulfide resin composition obtained by the manufacturing method described in claim 4.
A polyarylene sulfide resin composition in which carbon nanotubes are dispersed in a polyarylene sulfide resin,
Contains a polyarylene sulfide resin, carbon nanotubes, and a dispersion aid;
The content of the carbon nanotubes is 20 parts by mass or less based on 100 parts by mass of the polyarylene sulfide resin composition,
A polyarylene sulfide resin composition having a volume resistivity of 1.0×10 10 Ω·cm or less.
A polyarylene sulfide resin molded product obtained by melt molding the resin composition according to claim 6.