Polyphenylene sulfide resin composition and molded article

Abstract

To provide a polyphenylene sulfide resin composition which has small anisotropic property of electromagnetic wave absorption property, without largely impairing excellent mechanical strength and insulation property inherent to a polyphenylene sulfide resin, and a molded article of the same.SOLUTION: A polyphenylene sulfide resin composition is made by blending 0.5 pts.wt. or more and 15 pts.wt. or less of (B) a carbon nanotube, and 20 pts.wt. or more and 200 pts.wt. or less of (C) a modified cross section glass fiber, with respect to 100 pts.wt. of (A) a polyphenylene sulfide resin.SELECTED DRAWING: None

Description

[Technical field]

[0001] Provided are a polyphenylene sulfide resin composition having excellent electromagnetic wave absorption properties in the high frequency range without significantly impairing the excellent mechanical strength and insulating properties inherent to polyphenylene sulfide resin, and a molded article thereof. [Background technology]

[0002] Polyphenylene sulfide (hereinafter sometimes abbreviated as PPS) resin is widely used in electrical and electronic components, machine parts, and automotive parts because of its excellent heat resistance, flame retardancy, chemical resistance, electrical insulation, moist heat resistance, mechanical strength, and dimensional stability.

[0003] In recent years, the miniaturization and integration of electronic devices has led to the rapid spread of PCs, mobile phones, and other digital devices, resulting in electromagnetic waves being present in all environments. With the development of the electronics industry, the risk of electromagnetic interference is increasing.

[0004] In recent years, automated driving has been progressing in all kinds of fields, and it is processed by advanced sensor recognition technology and advanced calculations of digital devices. These automated driving contribute to the unmanned operation of public services and factories, and malfunction due to electromagnetic interference can lead to major problems. In particular, the practical application and development of automated driving of automobiles is based on the installation of many sensors, and there are concerns that malfunction of these sensors could lead to fatal accidents.

[0005] In addition, research results have shown that electromagnetic waves have negative effects on the human body, which has led to growing concerns and interest in the health hazards, and calls for stronger regulations and measures against electromagnetic interference.

[0006] As a countermeasure against such electromagnetic waves, most shielding materials use metal. Metal materials do not allow electromagnetic waves to pass through, but reflect most of the electromagnetic waves from their surfaces. This is because when electromagnetic waves come into contact with an electric conductor, electromagnetic induction generates eddy currents within the conductor, which reflect the electromagnetic waves.

[0007] On the other hand, insulating materials such as resins allow electromagnetic waves to pass through, so various attempts have been made to give resins electrical conductivity and electromagnetic wave shielding properties.

[0008] Resin compositions having such electrical conductivity are usually produced by mixing a conductive additive such as carbon black, carbon fiber, metal powder, metal-coated inorganic powder, or metal fiber with a polymer, but it is difficult to ensure the electrical conductivity of the resin composition at a desired level unless a significant amount of the conductive additive is added.

[0009] Furthermore, in the case of resin composites using carbon materials such as carbon black and carbon fiber, the incorporation of a large amount of inorganic materials leads to high hardness of the resin, surface roughness, and deterioration of physical properties, making this unrealistic.

[0010] In Patent Documents 1 and 2, a conductive material is provided by using carbon nanotubes (hereinafter sometimes abbreviated as CNT) and a filler in a resin. [Prior art documents] [Patent documents]

[0011] [Patent Document 1] Special Publication No. 2016-504470 [Patent Document 2] JP 2016-41806 A Summary of the Invention [Problem to be solved by the invention]

[0012] However, the resin compositions disclosed in Patent Documents 1 and 2, which aim to impart electrical conductivity to resins and provide electromagnetic shielding properties, cause anisotropy in the resin molded product due to the orientation of the glass fibers during injection molding. Furthermore, anisotropy occurs in the orientation of the CNTs, which also causes anisotropy in the electromagnetic shielding properties of the resulting molded product, resulting in a loss of freedom in designing the molded product to achieve the desired electromagnetic shielding properties.

[0013] Furthermore, in electromagnetic wave countermeasures using reflection, the reflected electromagnetic waves exist, so although the impact on the protected equipment is minimized, they still have an impact on other peripheral equipment and the human body. Therefore, there is a demand for absorbing the electromagnetic waves that are generated, rather than reflecting them.

[0014] The resin composition disclosed in Patent Document 2 contains a large amount of CNT, which leads to a decrease in insulating properties and further acts as a radio wave reflector, and therefore does not function as a desired electromagnetic wave absorber.

[0015] An object of the present invention is to provide a PPS resin composition having small anisotropy in electromagnetic wave absorption without significantly impairing the excellent mechanical strength and insulating properties inherent to PPS resin, and a molded article thereof. [Means for solving the problem]

[0016] The present inventors have conducted extensive research to solve the above problems and have arrived at the present invention. (1) A polyphenylene sulfide resin composition comprising (A) 100 parts by weight of polyphenylene sulfide resin, (B) 0.5 parts by weight or more and 15 parts by weight or less of carbon nanotubes, and (C) 20 parts by weight or more and 200 parts by weight or less of irregular cross section glass fibers. (2) The (B) carbon nanotubes have a purity of 90% by weight or more and a specific surface area of ​​190 m 2 / g or more 300m 2 / g or less. (3) The polyphenylene sulfide resin composition according to (1) or (2), characterized in that the ratio of the major axis (the longest linear distance in the cross section) to the minor axis (the longest linear distance perpendicular to the major axis) of the (C) modified cross section glass fiber is 1.3 to 10. (4) The polyphenylene sulfide resin composition according to any one of (1) to (3), further comprising (D) or (C) 0.1 part by weight or more and 150 parts by weight or less of an inorganic filler other than the modified cross section glass fiber, per 100 parts by weight of the polyphenylene sulfide resin. (5) The polyphenylene sulfide resin composition according to any one of (1) to (4), further comprising 0.5 parts by weight or more and 3.0 parts by weight or less of (F) carbon black per 100 parts by weight of the polyphenylene sulfide resin (A). (6) A method for producing the polyphenylene sulfide resin composition according to any one of (1) to (5), characterized in that the (A) polyphenylene sulfide resin, (B) carbon nanotubes and (C) modified cross section glass fibers are melt-kneaded at a resin temperature of 360° C. or less. (7) A molded article made of the polyphenylene sulfide resin composition according to any one of (1) to (5). (8) The molded article according to (7), which is an electromagnetic wave absorber. Effect of the Invention

[0017] By blending CNTs and glass fibers having a specific cross-sectional shape in a prescribed ratio with PPS resin, the present invention can provide a PPS resin composition and a molded article thereof that have small anisotropy in electromagnetic wave absorption without significantly impairing the excellent mechanical strength and insulating properties that are inherent to PPS resin. [Brief description of the drawings]

[0018] [Figure 1] FIG. 1 is a front view of a test sample (a flat plate of 80 mm×80 mm×2 mm thickness) used in the free space method. [Diagram 2] FIG. 2 is a side view of the test sample of FIG. 1. [Diagram 3] Schematic diagram of the free space method (evaluation in the MD direction). [Figure 4] This is a projection diagram when evaluating the MD direction using the free space method. [Diagram 5] This is a projection diagram when evaluating the TD direction of the free space method. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0019] Hereinafter, an embodiment of the present invention will be described in detail.

[0020] (A) Polyphenylene sulfide resin The PPS resin (A) used in the present invention is a polymer having a repeating unit represented by the following structural formula:

[0021] [ka]

[0022] From the viewpoint of heat resistance, a polymer containing 70 mol % or more, and more preferably 90 mol % or more, of a polymer containing a repeating unit represented by the above structural formula is preferable. In addition, about 30 mol % or less of the repeating units of the PPS resin may be composed of a repeating unit having the following structure.

[0023] [ka]

[0024] The method for producing the PPS resin used in the present invention will be described below. First, the contents of the polyhalogenated aromatic compound, sulfidizing agent, polymerization solvent, molecular weight regulator, polymerization aid and polymerization stabilizer used will be explained.

[0025] [Polyhalogenated aromatic compounds] Polyhalogenated aromatic compounds refer to compounds having two or more halogen atoms in one molecule. Specific examples include polyhalogenated aromatic compounds such as p-dichlorobenzene, m-dichlorobenzene, o-dichlorobenzene, 1,3,5-trichlorobenzene, 1,2,4-trichlorobenzene, 1,2,4,5-tetrachlorobenzene, hexachlorobenzene, 2,5-dichlorotoluene, 2,5-dichloro-p-xylene, 1,4-dibromobenzene, 1,4-diiodobenzene, and 1-methoxy-2,5-dichlorobenzene, and p-dichlorobenzene is preferred. In addition, it is possible to combine two or more different polyhalogenated aromatic compounds to form a copolymer, but it is preferred to use p-dihalogenated aromatic compounds in an amount of 70 mol% or more, and even 90 mol% or more, of the total polyhalogenated aromatic compounds.

[0026] The amount of the polyhalogenated aromatic compound used is, for example, in the range of 0.9 to 2.0 mol, preferably 0.95 to 1.5 mol, and more preferably 1.005 to 1.2 mol per mol of the sulfidizing agent in order to obtain a PPS resin with a viscosity suitable for processing.

[0027] [Sulfidizing agent] The sulfidizing agent includes alkali metal sulfides, alkali metal hydrosulfides, and hydrogen sulfide.

[0028] 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, with sodium sulfide being preferred. These alkali metal sulfides can be used as hydrates or aqueous mixtures, or in the anhydrous form.

[0029] Specific examples of the alkali metal hydrosulfide include sodium hydrosulfide, potassium hydrosulfide, lithium hydrosulfide, rubidium hydrosulfide, cesium hydrosulfide, and mixtures of two or more of these, with sodium hydrosulfide being preferred. These alkali metal hydrosulfides can be used as hydrates or aqueous mixtures, or in the anhydrous form.

[0030] In addition, a sulfidizing agent prepared in situ in the reaction system from an alkali metal hydrosulfide and an alkali metal hydroxide can also be used. Also, a sulfidizing agent can be prepared from an alkali metal hydrosulfide and an alkali metal hydroxide, and then transferred to a polymerization tank for use.

[0031] Alternatively, a sulfidizing agent prepared in situ in the reaction system from an alkali metal hydroxide such as lithium hydroxide or sodium hydroxide and hydrogen sulfide can be used. Also, a sulfidizing agent can be prepared from an alkali metal hydroxide such as lithium hydroxide or sodium hydroxide and hydrogen sulfide, and then transferred to a polymerization tank for use.

[0032] When a part of the sulfidizing agent is lost before the start of the polymerization reaction due to a dehydration operation or the like, the amount of the charged sulfidizing agent means the remaining amount obtained by subtracting the lost amount from the actual charged amount.

[0033] 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 the alkali metal hydroxide include, for example, sodium hydroxide, potassium hydroxide, lithium hydroxide, rubidium hydroxide, cesium hydroxide, and mixtures of two or more of these.Specific examples of the alkaline earth metal hydroxide include, for example, calcium hydroxide, strontium hydroxide, barium hydroxide, etc., and among these, sodium hydroxide is preferably used.

[0034] When an alkali metal hydrosulfide is used as the sulfidizing agent, it is particularly preferable to use an alkali metal hydroxide simultaneously. The amount of the alkali metal hydroxide used is, for example, in the range of 0.95 to 1.20 mol, preferably 1.00 to 1.15 mol, and more preferably 1.005 to 1.100 mol per mol of the alkali metal hydrosulfide.

[0035] [Polymerization solvent] As the polymerization solvent, it is preferable to use an organic polar solvent. Specific examples include N-alkylpyrrolidones such as N-methyl-2-pyrrolidone and N-ethyl-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, hexamethylphosphoric triamide, dimethylsulfone, and tetramethylene sulfoxide, and mixtures thereof, all of which are preferably used because of their high reaction stability. Among these, N-methyl-2-pyrrolidone (hereinafter sometimes abbreviated as NMP) is particularly preferably used.

[0036] The amount of the organic polar solvent used is selected from the range of 2.0 to 10 moles, preferably 2.25 to 6.0 moles, and more preferably 2.5 to 5.5 moles, per mole of the sulfidizing agent.

[0037] [Molecular weight regulator] A monohalogen compound (not necessarily an aromatic compound) can be used in combination with the polyhalogenated aromatic compound in order to form terminals in the resulting PPS resin or to adjust the polymerization reaction or molecular weight.

[0038] [Polymerization aid] In order to obtain a PPS resin with a relatively high degree of polymerization in a short time, it is also a preferred embodiment to use a polymerization aid. Here, the polymerization aid means a substance that has the effect of increasing the viscosity of the resulting PPS resin. Specific examples of such polymerization aids include organic carboxylates, water, alkali metal chlorides, organic sulfonates, alkali metal sulfates, alkaline earth metal oxides, alkali metal phosphates, and alkaline earth metal phosphates. These can be used alone or in combination of two or more. Among them, organic carboxylates and / or water are preferably used.

[0039] The above alkali metal carboxylate has the general formula R(COOM) n (wherein R is an alkyl group, a cycloalkyl group, an aryl group, an alkylaryl group, or an arylalkyl group having 1 to 20 carbon atoms; M is an alkali metal selected from lithium, sodium, potassium, rubidium, and cesium; and n is an integer of 1 to 3). The alkali metal carboxylate can also be used as a hydrate, anhydride, or an aqueous solution. Specific examples of the alkali metal carboxylate include lithium acetate, sodium acetate, potassium acetate, sodium propionate, lithium valerate, sodium benzoate, sodium phenylacetate, potassium p-toluate, and mixtures thereof.

[0040] The alkali metal carboxylate may be formed by adding and reacting an organic acid with one or more compounds selected from the group consisting of alkali metal hydroxides, alkali metal carbonates, and alkali metal bicarbonates in approximately equal chemical equivalents. Among the above alkali metal carboxylates, lithium salts have high solubility in the reaction system and have a large auxiliary effect, but are expensive, while potassium, rubidium, and cesium salts are thought to have insufficient solubility in the reaction system, so sodium acetate, which is inexpensive and has moderate solubility in the polymerization system, is most preferably used.

[0041] When these polymerization aids are used, the amount used is usually in the range of 0.01 mol to 0.7 mol per mol of the charged alkali metal sulfide, and in terms of obtaining a higher degree of polymerization, the range of 0.1 to 0.6 mol is preferable, and the range of 0.2 to 0.5 mol is more preferable.

[0042] The use of water as a polymerization aid is one of the effective means for obtaining a resin composition with a high balance between fluidity and high toughness. In this case, the amount of water added is usually in the range of 0.5 mol to 15 mol per mol of the charged alkali metal sulfide, and in terms of obtaining a higher degree of polymerization, the range of 0.6 to 10 mol is preferable, and the range of 1 to 5 mol is more preferable.

[0043] The timing of addition of these polymerization aids is not particularly specified, and they may be added at any time during the pre-step, at the start of polymerization, or during the polymerization, as described below, or may be added in several portions, but when an alkali metal carboxylate is used as the polymerization aid, it is more preferable to add it at the start of the pre-step or at the start of polymerization, because it is easy to add it. When water is used as the polymerization aid, it is effective to add it during the polymerization reaction after the polyhalogenated aromatic compound is charged.

[0044] [Polymerization stabilizer] A polymerization stabilizer can be used to stabilize the polymerization reaction system and prevent side reactions. The polymerization stabilizer contributes to the stabilization of the polymerization reaction system and suppresses undesirable side reactions. One indicator of side reactions is the generation of thiophenol, and the addition of a polymerization stabilizer can suppress the generation of thiophenol. Specific examples of polymerization stabilizers include compounds such as alkali metal hydroxides, alkali metal carbonates, alkaline earth metal hydroxides, and alkaline earth metal carbonates. Among these, alkali metal hydroxides such as sodium hydroxide, potassium hydroxide, and lithium hydroxide are preferred. The above-mentioned alkali metal carboxylates also act as polymerization stabilizers, and are therefore included in the polymerization stabilizers used in the present invention. In addition, when an alkali metal hydrosulfide is used as a sulfidizing agent, it is particularly preferable to use an alkali metal hydroxide at the same time, as described above. Here, an excess of an alkali metal hydroxide relative to the sulfidizing agent can also serve as a polymerization stabilizer.

[0045] These polymerization stabilizers can be used alone or in combination of two or more. The polymerization stabilizer is preferably used in a ratio of usually 0.02 to 0.2 mol, preferably 0.03 to 0.1 mol, more preferably 0.04 to 0.09 mol, per mol of the charged alkali metal sulfide. If this ratio is too small, the stabilizing effect is insufficient, and conversely, if it is too large, it is economically disadvantageous and the polymer yield tends to decrease.

[0046] The timing of adding the polymerization stabilizer is not particularly specified, and it may be added at any time during the pre-step described below, at the start of polymerization, or during the polymerization, or may be added in several portions, but it is more preferable to add it simultaneously at the start of the pre-step or at the start of polymerization.

[0047] Next, the pre-process, the polymerization reaction process, and the recovery process will be specifically described in order.

[0048] [Pre-process] The sulfidizing agent is usually used in the form of a hydrate, and it is preferable to heat the mixture containing the organic polar solvent and the sulfidizing agent before adding the polyhalogenated aromatic compound, and remove excess water from the system. If too much water is removed by this operation, it is preferable to add water to make up for the shortage.

[0049] As described above, the sulfidizing agent may be an alkali metal sulfide prepared in situ in the reaction system from an alkali metal hydrosulfide and an alkali metal hydroxide, or in a tank separate from the polymerization tank. There is no particular restriction on this method, but a preferable method is to add an alkali metal hydrosulfide and an alkali metal hydroxide to an organic polar solvent in an inert gas atmosphere at 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 245°C, under normal pressure or reduced pressure, to distill off water. A polymerization aid may be added at this stage. Toluene or the like may be added to promote the distillation of water.

[0050] In the polymerization reaction, the amount of water in the polymerization system is preferably 0.5 to 10.0 mol per 1 mol of the charged sulfidizing agent. Here, the amount of water in the polymerization system is the amount of water charged to the polymerization system minus the amount of water removed from the polymerization system. The charged water may be in any form such as water, an aqueous solution, or water of crystallization.

[0051] [Polymerization reaction process] It is preferable to produce the PPS resin powder by reacting a sulfidizing agent with a polyhalogenated aromatic compound in an organic polar solvent at a temperature within the range of 200° C. or higher and lower than 290° C.

[0052] When starting the polymerization reaction process, the sulfidizing agent and the polyhalogenated aromatic compound are added to the organic polar solvent, desirably in an inert gas atmosphere, at a temperature range of room temperature to 215° C., preferably 100 to 215° C. A polymerization aid may be added at this stage. The order of charging these raw materials may be random, or they may be charged simultaneously.

[0053] The mixture is usually heated to a temperature in the range of 200° C. to less than 290° C. There are no particular limitations on the heating rate, but a rate of 0.01 to 5° C. / min is usually selected, and a range of 0.1 to 3° C. / min is more preferable.

[0054] In general, the temperature is finally raised to 250 to less than 290° C., and the reaction is carried out at that temperature for usually 0.25 to 50 hours, preferably 0.5 to 20 hours.

[0055] In order to obtain a higher degree of polymerization, it is effective to react at 200° C. to 245° C. for a certain period of time before the final temperature is reached, and then to raise the temperature to 270 to less than 290° C. In this case, the reaction time at 200° C. to 245° C. is usually selected in the range of 0.25 hours to 20 hours, and preferably 0.25 hours to 10 hours.

[0056] In order to obtain a polymer with a higher degree of polymerization, it is effective to carry out the polymerization in multiple stages. When carrying out the polymerization in multiple stages, it is effective to raise the temperature to the next stage when the conversion rate of the polyhalogenated aromatic compound in the system at 245°C reaches 40 mol% or more, preferably 60 mol%.

[0057] [Recovery process] After the polymerization is completed, solids are recovered from the polymerization reaction mixture containing the polymer, the solvent, and the like.

[0058] The most preferred method for recovering PPS resin is to perform the recovery under rapid cooling conditions, and one preferred method for this recovery method is the flash method. In the flash method, the polymerization reaction product is subjected to high temperature and high pressure (usually 250°C or higher, 8 kg / cm 2 The method is to flash the polymer from the above state into an atmosphere of normal pressure or reduced pressure, recover the solvent, and recover the polymer in powder form at the same time. Flashing here means to eject the polymerization reaction product from a nozzle. Specific examples of the flashing atmosphere include nitrogen or water vapor at normal pressure, and the temperature is usually selected in the range of 150°C to 250°C.

[0059] The flash method is an economical method because it can recover solids at the same time as the solvent, and the recovery time can be relatively short. In this method, ionic compounds such as Na and organic low-polymerization substances (oligomers) tend to be easily incorporated into the polymer during the solidification process.

[0060] However, the method for recovering the PPS resin used in the present invention is not limited to the flash method. A method of recovering particulate polymer by slow cooling (quench method) can also be used as long as it satisfies the requirements of the present invention. However, in terms of economy and performance, it is more preferable that the production method of the present invention uses PPS resin recovered by the flash method.

[0061] In the manufacturing process of the PPS resin, a thermal oxidation treatment can be performed after the above-mentioned polymerization reaction step and recovery step. A hot water treatment step and an acid treatment step can also be performed before the thermal oxidation treatment step. A step of washing with an organic solvent can also be included before the acid treatment step or the hot water treatment step. The acid treatment step, the hot water treatment step, and the washing with an organic solvent can also be performed in appropriate combination.

[0062] The acid used in the acid treatment is not particularly limited as long as it does not have the effect of decomposing the PPS resin, and examples of the acid include acetic acid, hydrochloric acid, sulfuric acid, phosphoric acid, silicic acid, carbonic acid, and propylic acid. Of these, acetic acid and hydrochloric acid are more preferably used, but acids such as nitric acid, which decompose and deteriorate the PPS resin, are not preferred.

[0063] When an aqueous acid solution is used, the water is preferably distilled water or deionized water. The aqueous acid solution preferably has a pH of 1 to 7, more preferably a pH of 2 to 4. A pH of 7 or less is preferable because the metal content of the PPS resin does not increase, and a pH of 1 or more is preferable because the amount of volatile components in the PPS resin can be suppressed.

[0064] The acid treatment method is preferably to immerse the PPS resin in an acid or an aqueous solution of an acid, and if necessary, it is also possible to stir and heat appropriately. The temperature during heating is preferably 80 to 250°C, more preferably 120 to 200°C, and even more preferably 150 to 200°C. A temperature of 80°C or higher is preferable because the acid treatment effect can be obtained and the metal content does not increase, and a temperature of 250°C or lower is preferable from the viewpoint of safety because the pressure increase can be suppressed. In addition, when the PPS resin is immersed in an aqueous solution of an acid for treatment, the pH is preferably less than 8 by the acid treatment, and more preferably pH 2 to 8. A pH of less than 8 is preferable because the metal content of the resulting PPS resin does not increase.

[0065] The time for the acid treatment is preferably such that the reaction between the PPS resin and the acid reaches sufficient equilibrium, and when the treatment is performed at 80°C, it is preferably 2 to 24 hours, and when the treatment is performed at 200°C, it is preferably 0.01 to 5 hours.

[0066] The acid treatment is preferably performed in a state where the PPS resin is sufficiently immersed in the acid or the aqueous acid solution. The ratio of the PPS resin to the acid or the aqueous acid solution in the acid treatment is preferably 0.5 to 500 L of the acid or the aqueous acid solution per 500 g of PPS resin, more preferably 1 to 100 L, and even more preferably 2.5 to 20 L. By using 0.5 L or more of the acid or the aqueous acid solution per 500 g of PPS resin, the PPS resin is sufficiently immersed in the aqueous solution, so that poor cleaning can be suppressed and the metal content of the PPS resin does not increase, which is preferable. In addition, by using 500 L or less of the acid or the aqueous acid solution per 500 g of PPS resin, the amount of the solution is not excessively large relative to the PPS resin, so that the production efficiency is not significantly reduced, which is preferable.

[0067] These acid treatments are carried out by adding a predetermined amount of PPS resin to a predetermined amount of water and acid, heating and stirring in a pressure vessel, or by continuously performing acid treatment. The method for separating the aqueous solution and the PPS resin from the treatment solution after the acid treatment is simple filtration using a sieve or filter, and examples of such methods include natural filtration, pressure filtration, reduced pressure filtration, and centrifugal filtration. In order to remove the acid and impurities remaining on the surface of the PPS resin separated from the treatment solution, it is preferable to wash the PPS resin several times with water or hot water. Examples of the washing method include a method of filtering the PPS resin on a filter while pouring water on it, or a method of separating the aqueous solution and the PPS resin by adding the separated PPS resin to water prepared in advance and filtering it again. The water used for washing is preferably distilled water or deionized water.

[0068] In the present invention, it is preferable to carry out hot water treatment before the acid treatment step, and the method thereof is as follows. The water used in the hot water treatment in the present invention is preferably distilled water or deionized water. The hot water treatment temperature is preferably 80 to 250°C, more preferably 120 to 200°C, and even more preferably 150 to 200°C. By setting the temperature at 80°C or higher, the hot water treatment effect can be obtained and the amount of volatilized gas generation can be suppressed, while by setting the temperature at 250°C or lower, an increase in pressure can be suppressed, which is preferable from the standpoint of safety.

[0069] The hot water treatment time is preferably a time that allows sufficient extraction treatment of the PPS resin with hot water. For example, when treatment is performed at 80°C, 2 to 24 hours is preferable, and when treatment is performed at 200°C, 0.01 to 5 hours is preferable.

[0070] The ratio of PPS resin to water in the hot water treatment is preferably such that the PPS resin is sufficiently immersed in water, and is preferably 0.5 to 500 L of water per 500 g of PPS resin, more preferably 1 to 100 L, and even more preferably 2.5 to 20 L. By using 0.5 L or more of water per 500 g of PPS resin, the PPS resin is sufficiently immersed in water, which can suppress poor cleaning and does not increase the amount of volatile gas generated, and is therefore preferable. In addition, by using 500 L or less of water per 500 g of PPS resin, the amount of water is not excessive relative to the PPS resin, which is therefore preferable since it does not significantly reduce production efficiency.

[0071] There is no particular limit to the operation of these hot water treatments, and the method may be a method of putting a predetermined amount of PPS resin into a predetermined amount of water and heating and stirring in a pressure vessel, or a method of continuously performing hot water treatment. There is no particular limit to the method of separating the aqueous solution and the PPS resin from the treatment solution after the hot water treatment, but filtration using a sieve or filter is convenient, and examples of such methods include natural filtration, pressure filtration, reduced pressure filtration, and centrifugal filtration. In order to remove impurities remaining on the surface of the PPS resin separated from the treatment solution, it is preferable to wash the PPS resin several times with water or hot water. There is no particular limit to the washing method, but examples of such methods include a method of filtering the PPS resin on a filter while pouring water on it, and a method of filtering the PPS resin again after the separated PPS resin is put into water prepared in advance. The water used for washing is preferably distilled water or deionized water.

[0072] In addition, since decomposition of the PPS terminal groups during the acid treatment or hot water treatment is undesirable, it is desirable to carry out the acid treatment or hot water treatment in an inert atmosphere. Examples of the inert atmosphere include nitrogen, helium, and argon, and from the viewpoint of economy, a nitrogen atmosphere is preferable.

[0073] In the present invention, a step of washing with an organic solvent may be included prior to the acid treatment step or the hot water treatment step, and the method thereof is as follows: The organic solvent used in washing the PPS resin in the present invention is not particularly limited as long as it does not have the action of decomposing the PPS resin, and examples thereof include nitrogen-containing polar solvents such as N-methyl-2-pyrrolidone, dimethylformamide, dimethylacetamide, 1,3-dimethylimidazolidinone, hexamethylphosphoramide, piperazinones, etc.; sulfoxide / sulfone solvents such as dimethyl sulfoxide, dimethyl sulfone, sulfolane, etc.; ketone solvents such as acetone, methyl ethyl ketone, diethyl ketone, acetophenone, etc.; dimethyl ether, dipropyl ether, dioxane, tetrahydrofuran, etc.; Examples of the organic solvent include ether solvents such as fluorofuran, halogen-based solvents such as chloroform, methylene chloride, trichloroethylene, ethylene dichloride, perchloroethylene, monochloroethane, dichloroethane, tetrachloroethane, perchloroethane, and chlorobenzene, alcohol-phenol solvents such as methanol, ethanol, propanol, butanol, pentanol, ethylene glycol, propylene glycol, phenol, cresol, polyethylene glycol, and polypropylene glycol, and aromatic hydrocarbon solvents such as benzene, toluene, and xylene. Among these organic solvents, N-methyl-2-pyrrolidone, acetone, dimethylformamide, and chloroform are particularly preferred. These organic solvents are used alone or in combination of two or more.

[0074] The method of washing with an organic solvent includes immersing the PPS resin in the organic solvent, and stirring or heating can be performed as necessary. There is no particular restriction on the washing temperature when washing the PPS resin with an organic solvent, and any temperature between room temperature and about 300°C can be selected. The higher the washing temperature, the higher the washing efficiency tends to be, but usually a washing temperature between room temperature and 150°C is sufficient. Washing can also be performed under pressure in a pressure vessel at a temperature above the boiling point of the organic solvent. There is also no particular restriction on the washing time. Although it depends on the washing conditions, in the case of batch washing, washing for 5 minutes or more usually produces a sufficient effect. Continuous washing is also possible.

[0075] The PPS resin used in the present invention is preferably obtained by carrying out the above-mentioned acid treatment, hot water treatment, or washing with an organic solvent followed by thermal oxidation treatment. The thermal oxidation treatment is a treatment in which the PPS resin is heated in an oxygen atmosphere or heated with the addition of a peroxide such as H2O2 or a vulcanizing agent such as S, and heating in an oxygen atmosphere is particularly preferred for the sake of ease of treatment.

[0076] The heating device for the thermal oxidation treatment of PPS resin may be a normal hot air dryer or a heating device of the rotary type or with stirring blades, but in the case of efficient and more uniform treatment, it is more preferable to use a heating device of the rotary type or with stirring blades. The oxygen concentration in the atmosphere during the thermal oxidation treatment is desirably 1% by volume or more, and more desirably 2% by volume or more. In order to achieve the effects of the present invention, the upper limit of the oxygen concentration is preferably 5% by volume or less. By carrying out the thermal oxidation treatment at an oxygen concentration of 5% by volume or less, the thermal oxidation treatment does not proceed excessively, and the toughness of the molded product containing the PPS resin that has been subjected to the thermal oxidation treatment is not impaired. On the other hand, it is preferable to carry out the thermal oxidation treatment at an oxygen concentration of 1% by volume or more, since sufficient thermal oxidation treatment can be performed and a PPS resin with a small amount of volatile components can be obtained.

[0077] The thermal oxidation treatment temperature for PPS resin is preferably 160 to 270° C., more preferably 160 to 230° C. By carrying out the thermal oxidation treatment at 270° C. or less, the thermal oxidation treatment does not proceed too rapidly, and the toughness of a molded article containing the PPS resin that has been subjected to the thermal oxidation treatment is not impaired, which is preferable. On the other hand, by carrying out the thermal oxidation treatment at a temperature of 160° C. or more, the thermal oxidation treatment can proceed at an appropriate rate, and a PPS resin that generates a small amount of volatile components can be obtained, which is preferable.

[0078] The treatment time of the thermal oxidation treatment is preferably 0.5 to 30 hours, more preferably 0.5 to 25 hours, and even more preferably 2 to 20 hours. By setting the treatment time to 0.5 hours or more, it is possible to perform sufficient thermal oxidation treatment and obtain a PPS resin with a small amount of volatile components, which is preferable. By setting the treatment time to 30 hours or less, it is possible to control the crosslinking reaction due to the thermal oxidation treatment and it is preferable that the toughness of a molded article containing the PPS resin that has been subjected to the thermal oxidation treatment is not impaired.

[0079] (B) Carbon nanotubes The polyphenylene sulfide resin composition of the present invention must contain 0.5 to 15 parts by weight of (B) carbon nanotubes per 100 parts by weight of (A) polyphenylene sulfide resin.

[0080] The carbon nanotube (B) of the present invention (hereinafter sometimes abbreviated as CNT) preferably has a diameter of 5 nm or more and 20 nm or less. More preferably, it is 7 nm or more and 17 nm or less, and further preferably, it is 10 nm or more and 15 nm or less. When the diameter of the CNT is 5 nm or more, the electromagnetic wave absorption performance is fully exhibited, and when it is 20 nm or less, the insulation property is not deteriorated, so it is preferable.

[0081] (B) CNT preferably has a carbon purity of 90% by weight or more, more preferably 95% by weight or more. When the carbon purity is 90% by weight or more, a significant increase in viscosity due to metal impurities is suppressed, and furthermore, electromagnetic wave absorption properties can be maintained, and reflection performance is reduced, which is preferable.

[0082] (B) CNT has a specific surface area of ​​190 m 2 / g or more 300m 2 / g or less, and more preferably 230m 2 / g or more 290m 2 / g or less. This specific surface area is 190m 2 / g or more, the absorption performance against electromagnetic waves is good and the 2 / g or less is preferable because the fluidity of the material can be maintained and the deterioration of the insulating properties can be suppressed.

[0083] In the resin composition of the present invention, the lower limit of the blending amount of (B) CNT must be 0.5 parts by weight or more relative to 100 parts by weight of (A) polyphenylene sulfide resin, and is preferably more than 0.8 parts by weight, and more preferably 1 part by weight or more. The upper limit is 15 parts by weight or less, preferably 10 parts by weight or less, and more preferably 6 parts by weight or less. If the amount of (B) CNT is less than 0.5 parts by weight relative to 100 parts by weight of (A) polyphenylene sulfide resin, the electromagnetic wave absorption performance decreases, and if it exceeds 15 parts by weight, the insulating properties decrease significantly.

[0084] A commercially available CNT product is available, for example, from Kumho Petrochemical Co., Ltd. under the product name T210.

[0085] (C) Irregular cross-section glass fiber The polyphenylene sulfide resin composition of the present invention contains 20 parts by weight or more and 200 parts by weight or less of modified cross section glass fiber (C) based on 100 parts by weight of polyphenylene sulfide resin (A).

[0086] The modified cross section glass fiber (C) of the present invention is a glass fiber having a flat cross section (hereinafter may be abbreviated as flat glass fiber), and in a cross section perpendicular to the length direction, the ratio of the major axis (the longest linear distance in the cross section) to the minor axis (the longest linear distance in the direction perpendicular to the major axis) (major axis / minor axis ratio; hereinafter may be abbreviated as flattening) is preferably 1.3 to 10, more preferably 1.5 to 7, and further preferably 1.5 to 5.

[0087] The glass fiber having a flat cross section preferably has a major axis of 10 to 80 μm, which makes it easy to spin the glass fiber and allows the strength of the glass fiber to be maintained at a high level. More preferably, it is 15 μm or more and 50 μm or less. In addition, the minor axis of the cross section is preferably 2 to 20 μm, more preferably 4 μm or more and 15 μm or less.

[0088] The long axis / short axis ratio (flatness) of the cross section of the glass fiber was determined by observing with a scanning electron microscope, measuring the long axis and short axis of the cross section of 50 randomly selected glass fibers, calculating the ratio, and then calculating the number average.

[0089] Glass fibers having a flat cross section have a larger specific surface area than glass fibers having a circular cross section with the same cross section. In addition, since glass fibers are easily oriented in the flow direction of the molded product, collisions between glass fibers during molding are reduced, and breakage is further suppressed. In addition, the orientation of glass fibers further reduces anisotropy in the molded product. The anisotropy referred to here refers to the difference in molding shrinkage between the resin flow direction (MD direction) and the direction perpendicular to the flow direction (TD direction) of a molded product molded by injection molding with a size of 80 mm x 80 mm x 3 mm, and the difference in S21 of the S parameter obtained by the free space method. In addition, a resin composition containing glass fibers having a flat cross section can give a molded product with excellent mechanical strength, weld strength, impact strength, and high-temperature rigidity.

[0090] The lower limit of the amount of the modified cross section glass fiber (C) used in the present invention must be 20 parts by weight or more, and preferably exceeds 25 parts by weight, per 100 parts by weight of the polyphenylene sulfide resin (A). The upper limit must be 200 parts by weight or less, and preferably 180 parts by weight or less. If the amount of the modified cross section glass fiber (C) is less than 20 parts by weight per 100 parts by weight of the polyphenylene sulfide resin (A), the anisotropy decreases, and if it exceeds 200 parts by weight, the moldability deteriorates and the molded product becomes brittle.

[0091] (D)(C) Inorganic fillers other than irregular cross-section glass fibers The polyphenylene sulfide resin composition of the present invention may contain inorganic fillers other than (D)(C) irregular cross section glass fibers (hereinafter sometimes abbreviated as (D) inorganic fillers) within the range that does not impair the effects of the present invention. (D) inorganic fillers include (D1)(C) fibrous inorganic fillers other than irregular cross section glass fibers (hereinafter sometimes abbreviated as (D1) fibrous inorganic fillers) and (D2) non-fibrous inorganic fillers, and can be used alone or in combination.

[0092] Specific examples of such (D1) fibrous inorganic fillers include glass fibers other than (C) modified cross-section glass fibers, milled glass fibers, stainless steel fibers, aluminum fibers, brass fibers, rock wool, PAN-based and pitch-based carbon fibers, carbon nanotubes, carbon nanofibers, calcium carbonate whiskers, wollastonite whiskers, potassium titanate whiskers, barium titanate whiskers, aluminum borate whiskers, silicon nitride whiskers, aramid fibers, alumina fibers, silicon carbide fibers, asbestos fibers, gypsum fibers, ceramic fibers, zirconia fibers, silica fibers, titanium oxide fibers, silicon carbide fibers, etc., and these can be used in combination of two or more. In addition, it is preferable to pretreat these fibrous fillers with coupling agents such as isocyanate compounds, organic silane compounds, organic titanate compounds, organic borane compounds, and epoxy compounds in order to obtain better mechanical strength. Preferred examples include glass fibers and carbon fibers, and particularly preferred examples include glass fibers other than (C) modified cross-section glass fibers.

[0093] Specific examples of such (D2) non-fibrous inorganic fillers include fullerene, talc, wollastonite, zeolite, sericite, mica, kaolin, clay, pyrophyllite, bentonite, asbestos, silicates such as alumina silicate, metal compounds such as silicon oxide, magnesium oxide, alumina, zirconium oxide, titanium oxide, and iron oxide, carbonates such as calcium carbonate, magnesium carbonate, and dolomite, sulfates such as calcium sulfate and barium sulfate, glass beads, glass flakes, glass powder, ceramic beads, boron nitride, silicon carbide, carbon black, silica, and graphite. These may be hollow, and two or more of these non-fibrous inorganic fillers may be used in combination. In addition, these non-fibrous inorganic fillers may be pretreated with a coupling agent such as an isocyanate compound, an organic silane compound, an organic titanate compound, an organic borane compound, and an epoxy compound before use.

[0094] Among these, calcium carbonate is preferred from the viewpoints of mechanical strength and resistance to thermal shock.

[0095] The lower limit of the amount of inorganic filler (D) used in the present invention is preferably 0.1 parts by weight or more relative to 100 parts by weight of polyphenylene sulfide resin (A). More preferably, it is more than 20 parts by weight. The upper limit is preferably 150 parts by weight or less, more preferably 80 parts by weight or less. When the inorganic filler (D) is 0.1 parts by weight or more relative to 100 parts by weight of polyphenylene sulfide resin (A), the crystallization rate is stable. When it is 150 parts by weight or less, the mechanical strength and resistance to cold and heat shocks can be maintained.

[0096] (E) Elastomer The polyphenylene sulfide resin composition of the present invention may be further blended with an elastomer (E) within the range that does not impair the effects of the present invention. It is preferable to use such an elastomer (E) in combination with a modified olefin copolymer having an epoxy group (E-1) and an unmodified olefin copolymer (E-2). Details will be described later.

[0097] The lower limit of the blending amount of the (E) elastomer in the present invention is preferably 5 parts by weight or more per 100 parts by weight of the (A) polyphenylene sulfide resin. More preferably 7 parts by weight or more, and even more preferably 8 parts by weight or more. The upper limit is preferably less than 30 parts by weight, more preferably 25 parts by weight or less, and even more preferably 20 parts by weight or less. When the (E) elastomer is 5 parts by weight or more per 100 parts by weight of the (A) polyphenylene sulfide resin, the toughness and thermal shock resistance can be improved, and when it is less than 30 parts by weight, the decrease in flame retardancy can be suppressed.

[0098] The lower limit of the amount of the modified olefin copolymer having an epoxy group (E-1) used in the present invention is preferably 5 parts by weight or more, more preferably 6 parts by weight or more, relative to 100 parts by weight of the polyphenylene sulfide resin (A) from the viewpoint of obtaining resistance to cold and heat shock. The upper limit of the amount of the modified olefin copolymer having an epoxy group (E-1) used in the present invention is preferably less than 30 parts by weight, more preferably 25 parts by weight or less, and even more preferably 20 parts by weight or less, relative to 100 parts by weight of the polyphenylene sulfide resin (A) from the viewpoint of obtaining flame retardancy.

[0099] Modified olefin copolymers having epoxy groups include (co)polymers obtained by polymerizing α-olefins such as ethylene, propylene, 1-butene, 1-pentene, 1-octene, 4-methyl-1-pentene, and isobutylene alone or two or more of them, and copolymers of α-olefins and α,β-unsaturated acids and their alkyl esters such as acrylic acid, methyl acrylate, ethyl acrylate, butyl acrylate, methacrylic acid, methyl methacrylate, ethyl methacrylate, and butyl methacrylate, for example, which are obtained by introducing a monomer component having an epoxy group (a functional group-containing component) into ethylene / propylene copolymers (" / " indicates copolymerization, the same applies below), ethylene / 1-butene copolymers, ethylene / 1-hexene, ethylene / 1-octene, ethylene / methyl acrylate copolymers, ethylene / ethyl acrylate copolymers, ethylene / butyl acrylate copolymers, ethylene / methyl methacrylate copolymers, ethylene / ethyl methacrylate copolymers, and ethylene / butyl methacrylate copolymers. Examples of functional group-containing components include monomers containing epoxy groups, such as glycidyl acrylate, glycidyl methacrylate, glycidyl ethacrylate, glycidyl itaconate, and glycidyl citraconate. There are no particular limitations on the method of introducing these functional group-containing components, and methods such as copolymerization during (co)polymerization of olefin-based (co)polymers, or graft introduction into olefin-based (co)polymers using a radical initiator can be used. Particularly useful examples of modified olefin-based copolymers having epoxy groups obtained by introducing functional group-containing components into olefin-based (co)polymers include ethylene / propylene-g-glycidyl methacrylate copolymer ("g" represents graft, the same applies below), ethylene / 1-butene-g-glycidyl methacrylate copolymer, ethylene / glycidyl acrylate copolymer, ethylene / glycidyl methacrylate copolymer, ethylene / methyl acrylate / glycidyl methacrylate copolymer, and ethylene / methyl methacrylate / glycidyl methacrylate copolymer. Alternatively, epoxy group-containing olefin copolymers containing other monomers as essential components in addition to an α-olefin such as ethylene or propylene and a glycidyl ester of an α,β-unsaturated acid can also be suitably used.

[0100] Among them, from the viewpoint of thermal shock resistance, olefin copolymers containing a structure derived from glycidyl ester of α,β-unsaturated acid are preferred, and ethylene / methyl acrylate / glycidyl methacrylate copolymers are more preferred. The lower limit of the content of the structural unit derived from glycidyl ester of α,β-unsaturated acid is preferably 0.01 parts by weight or more, and more preferably 0.03 parts by weight or more, when the total resin composition is 100 parts by weight. The upper limit of the content of the structural unit derived from glycidyl ester of α,β-unsaturated acid is preferably less than 0.15 parts by weight, and more preferably 0.10 parts by weight or less, when the total resin composition is 100 parts by weight. By making the content of the structural unit derived from glycidyl ester of α,β-unsaturated acid 0.01 parts by weight or more, thermal shock resistance can be maintained, and by making it less than 0.15 parts by weight, flame retardancy can also be maintained.

[0101] Furthermore, it is preferable to use a modified olefin copolymer having an epoxy group (E-1) and an unmodified olefin copolymer having no polar functional group (E-2) in combination as the elastomer (E) in order to obtain excellent moldability and resistance to cold and hot shocks. There is no particular restriction on the ratio of these, but it is preferable that the weight ratio E1 / E2 is 1.0 or more and 3.0 or less, and more preferably 1.1 or more and 2.5 or less, when the blending weight of (E-1) is E1 and the blending weight of (E-2) is E2 relative to 100 parts by weight of the polyphenylene sulfide resin (A). It is more preferable that E1 / E2 is in this range because it provides an excellent balance between moldability and resistance to cold and hot shocks.

[0102] On the other hand, the unmodified olefin copolymer having no polar functional group (E-2) is preferably the same copolymer as the olefin copolymer constituting the modified olefin copolymer having an epoxy group (E-1).Of these, from the viewpoint of resistance to cold and heat shock, an ethylene / butyl acrylate copolymer is preferred.

[0103] (F) Carbon black Furthermore, (F) carbon black may be added to the PPS resin composition of the present invention, provided that the effects of the present invention are not impaired.

[0104] The lower limit of the blending amount of (F) carbon black in the present invention is preferably 0.5 parts by weight or more, and more preferably more than 0.8 parts by weight, relative to 100 parts by weight of (A) polyphenylene sulfide resin. The upper limit is preferably 3.0 parts by weight or less, and more preferably 2.0 parts by weight or less. When the amount of (F) carbon black is 0.5 parts by weight or more relative to 100 parts by weight of (A) polyphenylene sulfide resin, electromagnetic wave absorption performance can be exhibited, and when the amount is 3.0 parts by weight or less, deterioration of insulating properties can be suppressed.

[0105] Furthermore, a silane-based compound may be added to the PPS resin composition used in the present invention for the purpose of improving mechanical strength, toughness, etc., within the scope of not impairing the effects of the present invention. Examples of the silane-based compound include isocyanate group-containing alkoxysilane compounds such as γ-isocyanate propyl triethoxysilane, γ-isocyanate propyl trimethoxysilane, γ-isocyanate propyl methyl dimethoxysilane, γ-isocyanate propyl methyl diethoxysilane, γ-isocyanate propyl ethyl dimethoxysilane, γ-isocyanate propyl ethyl diethoxysilane, and γ-isocyanate propyl trichlorosilane; epoxy group-containing alkoxysilane compounds such as γ-glycidoxypropyl trimethoxysilane, γ-glycidoxypropyl triethoxysilane, and β-(3,4-epoxycyclohexyl)ethyl trimethoxysilane; amino group-containing alkoxysilane compounds such as γ-(2-aminoethyl) aminopropyl methyl dimethoxysilane, γ-(2-aminoethyl) aminopropyl trimethoxysilane, and γ-aminopropyl trimethoxysilane; and modified silicone oils having epoxy groups, amino groups, isocyanate groups, and hydroxyl groups. Among them, alkoxysilanes having an epoxy group, an amino group, an isocyanate group, or a hydroxyl group are particularly suitable for obtaining excellent mechanical strength and resistance to cold and heat shocks. The preferred amount of such silane compounds to be added is selected from the range of 0.05 to 3 parts by weight based on 100 parts by weight of the (A) PPS resin.

[0106] Furthermore, the PPS resin composition used in the present invention may be blended with other resins than the PPS resin, as long as the effects of the present invention are not impaired. There are no particular limitations on the resins that can be blended, but specific examples include polyamide, polyethylene terephthalate, polyether ether ketone resin, and vinyl aromatic compound block copolymers.

[0107] Furthermore, in order to maintain high heat resistance and thermal stability, it is preferable that the PPS resin composition of the present invention contains one or more antioxidants selected from phenolic and phosphorus-based compounds, within a range that does not impair the effects of the present invention. The amount of such antioxidants to be added is preferably 0.01 parts by weight or more, particularly 0.02 parts by weight or more, per 100 parts by weight of the PPS resin (A) from the viewpoint of the heat resistance improvement effect, and is preferably 5 parts by weight or less, particularly 1 part by weight or less, from the viewpoint of gas components generated during molding. In addition, the combined use of phenolic and phosphorus-based antioxidants is preferable, since it has a particularly large effect of maintaining heat resistance and thermal stability.

[0108] The method for producing the PPS resin composition of the present invention is preferably a method in which each raw material is supplied to a commonly known melt mixer such as a single-screw or twin-screw extruder, a Banbury mixer, a kneader, and a mixing roll, and kneaded at a barrel temperature of 280 to 330 ° C. of the extruder. In addition, it is preferable that the resin temperature obtained by directly measuring the resin coming out of the die during production is 360 ° C. or less. By setting the resin temperature to 360 ° C. or less, it is possible to suppress a sudden increase in viscosity due to the excessive reaction of metal impurities of CNT with various raw materials, which is preferable. In addition, by setting the temperature to 280 ° C. or more, which is below the melting point of the PPS resin, melt kneading is easy and the dispersibility of each material is improved, which is preferable. There is no particular restriction on the mixing order of the raw materials, and any method may be used, such as a method in which all raw materials are mixed and then melt kneaded by the above method, a method in which some raw materials are mixed and then melt kneaded by the above method, and the remaining raw materials are further mixed and melt kneaded, or a method in which some raw materials are mixed and then the remaining raw materials are mixed using a side feeder while melt kneading with a single-screw or twin-screw extruder. Furthermore, the small amount of additive components can be added to the mixture before molding after kneading and pelletizing the other components by the above-mentioned method or the like.

[0109] The PPS resin composition of the present invention thus obtained can be subjected to various molding processes such as injection molding, extrusion molding, blow molding and transfer molding, but is particularly suitable for injection molding.

[0110] In the free space method, which is a method for evaluating the electromagnetic wave absorbency of an electromagnetic wave absorber, the molded article made of the PPS resin composition of the present invention preferably has an S21 value of -10 dB or less, more preferably -15 dB or less, at a frequency of 65 GHz to 90 GHz, obtained by using a resin plate molded article of 80 mm x 80 mm x 2 mm thickness as a test sample. Furthermore, the ratio S21 (hereinafter referred to as S21[MD]) measured by placing a test sample so that the resin flow direction (MD) during molding is perpendicular to the measuring device installation surface, and S21 (hereinafter referred to as S21[TD]) measured by placing a test sample so that the resin flow direction (TD) during molding is perpendicular to the measuring device installation surface, is preferably 0.70 to 0.90. The molded article made of the PPS resin composition of the present invention preferably has either S21[TD] or S21[MD] of -10 dB or less, more preferably both S21[TD] and S21[MD] of -10 dB or less. Even more preferably, both S21[TD] and S21[MD] of -15 dB or less. The free space method is a method of measuring S parameters by placing transmitting and receiving antennas opposite each other and placing a sample at the midpoint between them.

[0111] Molded articles made of PPS resin compositions having an S21 value of -15 dB or less in the free space method are applicable to products that require electromagnetic wave absorption and are also lightweight, and are preferable. Conventionally, in order to achieve electromagnetic wave absorption, PPS resin, which does not inherently have electromagnetic wave absorption performance, is insufficient, and it is considered to add a large amount of carbon fiber or the like. However, such resin compositions have the disadvantage of lowering insulation and also exhibiting electromagnetic wave reflection. In the present invention, by blending 0.5 parts by weight to 15 parts by weight of (B) carbon nanotubes and 20 parts by weight to 200 parts by weight of (C) modified cross-section glass fibers with respect to 100 parts by weight of (A) polyphenylene sulfide resin, it is possible to achieve both electromagnetic wave absorption, insulation, and mechanical strength, which is preferable. Furthermore, by using (C) modified cross-section glass fibers, it is possible to obtain molded articles with small anisotropy of electromagnetic wave absorption.

[0112] The PPS resin composition of the present invention has excellent mechanical strength and electromagnetic wave absorption properties, and therefore can reduce electromagnetic noise leakage when applied to electrical and electronic components and automotive and vehicle-related components, where leakage of electromagnetic noise is undesirable.

[0113] Other applications of the PPS resin composition of the present invention include electric and electronic components such as sensors, consumer connectors, sockets, resistors, relay cases, switches, coil bobbins, capacitors, oscillators, various terminal boards, transformers, plugs, printed circuit boards, tuners, speakers, microphones, headphones, small motors, magnetic head bases, semiconductors, and computer-related components; and home and office electrical product components such as VTR components, television components, irons, hair dryers, rice cooker components, microwave oven components, audio components, audio equipment components such as audio, laser discs (registered trademark), and compact discs, lighting components, refrigerator components, air conditioner components, typewriter components, and word processor components. Other examples of applications include office computer-related parts, telephone-related parts, facsimile-related parts, copier-related parts, motor parts, and other machinery-related parts: exhaust gas sensors, coolant sensors, oil temperature sensors, throttle position sensors, crankshaft position sensors, air flow meters, brake pad wear sensors, air conditioner thermostat bases, heating hot air flow control valves, radiator motor brush holders, water pump impellers, water pump housings, engine cooling modules, turbine vanes, wiper motor-related parts, distributors, starter switches, starter relays, transmission wire harnesses, windshield washer nozzles, air conditioner panel switch boards, fuel-related electromagnetic valve coils, fuse connectors, horn terminals, electrical component insulating plates, ignition device cases, vehicle speed sensors, cable liners, and other automobile and vehicle-related parts. EXAMPLES

[0114] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to the descriptions of these examples.

[0115] [Evaluation method of PPS resin produced in the reference example] (1) Melt flow rate (MFR) The measurement was performed at a temperature of 315.5°C under a load of 5000g in accordance with a method conforming to ASTM-D1238-70.

[0116] [Reference Example 1] Polymerization of PPS (PPS-1) In an autoclave equipped with a stirrer and a valve at the bottom, 8267.4g (70.0 mol) of 47.5% sodium hydrosulfide, 2925.0g (70.2 mol) of 96% sodium hydroxide, 13860.0g (140.0 mol) of N-methyl-2-pyrrolidone (NMP), 1894.2g (23.1 mol) of sodium acetate, and 10500.0g of ion-exchanged water were charged, and the mixture was gradually heated to 240°C over about 3 hours while passing nitrogen through it at normal pressure. After distilling out 14772.1g of water and 280.0g of NMP, the reaction vessel was cooled to 160°C. The amount of water remaining in the system per mole of charged alkali metal sulfide was 1.08 mol, including the water consumed in the hydrolysis of NMP. The amount of hydrogen sulfide scattered was 0.023 mol per mole of charged alkali metal sulfide.

[0117] Next, 10,646.7 g (72.4 mol) of p-dichlorobenzene (p-DCB) and 6,444.9 g (65.1 mol) of NMP were added, the reaction vessel was sealed under nitrogen gas, and the temperature was raised from 200° C. to 270° C. at a rate of 0.6° C. / min while stirring at 240 rpm, and held at 270° C. for 70 minutes. The extraction valve at the bottom of the autoclave was opened, and the contents were flushed into a vessel equipped with a stirrer over 15 minutes while pressurizing with nitrogen, and most of the NMP was removed by stirring at 250° C. for a while.

[0118] The obtained solid matter and 53 liters of ion-exchanged water were placed in an autoclave equipped with a stirrer, washed at 70°C for 30 minutes, and then suction filtered through a glass filter with a pore size of 10 to 16 μm. Next, 60 liters of ion-exchanged water heated to 70°C was poured into a glass filter with a pore size of 10 to 16 μm, and suction filtered to obtain 18,000 g of PPS resin cake (including 7,550 g of PPS resin).

[0119] 18000g of the PPS resin cake, 40 liters of ion-exchanged water, and 43g of acetic acid were charged into an autoclave equipped with a stirrer, and the inside of the autoclave was replaced with nitrogen, and then the temperature was raised to 192°C and held for 30 minutes to perform acid treatment. The pH during the acid treatment was 7. After cooling the autoclave, the contents were filtered through a glass filter with a pore size of 10 to 16 μm. Next, 60 liters of ion-exchanged water heated to 70°C was poured into the glass filter, and suction filtration was performed to obtain a cake. The obtained cake was dried at 120°C for 4 hours under a nitrogen stream to obtain a powder of PPS resin subjected to acid treatment. Next, this PPS resin powder was placed in a heating device equipped with a stirrer with a volume of 100 liters, and subjected to thermal oxidation treatment at 200°C and an oxygen concentration of 21% for 2 hours. The thermal oxidation treatment was performed in an air atmosphere of 1.96 liters / min to obtain a crosslinked PPS-1. The MFR of the obtained polymer was 554g / 10min.

[0120] [Reference Example 2] PPS-2 In a 70-liter autoclave equipped with a stirrer and a bottom plug valve, 8.27 kg (70.00 mol) of 47.5% sodium hydrosulfide, 2.91 kg (69.80 mol) of 96% sodium hydroxide, 11.45 kg (115.50 mol) of N-methyl-2-pyrrolidone (NMP), and 10.5 kg of ion-exchanged water were charged, and the mixture was gradually heated to 245°C over about 3 hours while passing nitrogen through it at normal pressure. After distilling out 14.78 kg of water and 0.28 kg of NMP, the reaction vessel was cooled to 200°C. The amount of water remaining in the system per mole of charged alkali metal sulfide was 1.06 mol, including the water consumed in the hydrolysis of NMP. The amount of hydrogen sulfide scattered was 0.02 mol per mole of charged alkali metal sulfide.

[0121] The mixture was then cooled to 200°C, 10.48 kg (71.27 mol) of p-dichlorobenzene and 9.37 kg (94.50 mol) of NMP were added, the reaction vessel was sealed under nitrogen gas, and the temperature was increased from 200°C to 270°C at a rate of 0.6°C / min while stirring at 240 rpm. After reacting for 100 minutes at 270°C, the bottom plug valve of the autoclave was opened, and the contents were flushed into a vessel equipped with a stirrer over 15 minutes while pressurizing with nitrogen, and most of the NMP was removed by stirring for a while at 250°C.

[0122] The obtained solid matter and 76 L of ion-exchanged water were placed in an autoclave equipped with a stirrer, washed at 70° C. for 30 minutes, and then suction filtered through a glass filter. Next, 76 L of ion-exchanged water heated to 70° C. was poured into the glass filter, and suction filtered to obtain a cake.

[0123] The obtained cake and 90 liters of ion-exchanged water were charged into an autoclave equipped with a stirrer, and acetic acid was added to adjust the pH to 7. After the inside of the autoclave was replaced with nitrogen, the temperature was raised to 192°C and maintained at that temperature for 30 minutes. The autoclave was then cooled and the contents were removed.

[0124] The contents were filtered by suction using a glass filter, and then 76 liters of ion-exchanged water at 70°C was poured into the mixture and filtered by suction to obtain a cake. The cake was dried at 120°C under a nitrogen stream to obtain a dried PPS. The PPS obtained had an ER of 90g / 10min, which was converted to an MFR of 6257g / 10min.

[0125] [Reference Example 3] PPS-3 In a 70-liter autoclave equipped with a stirrer and a bottom plug valve, 8.27 kg (70.00 mol) of 47.5% sodium hydrosulfide, 2.94 kg (70.63 mol) of 96% sodium hydroxide, 11.45 kg (115.50 mol) of N-methyl-2-pyrrolidone (NMP), 1.89 kg (23.1 mol) of sodium acetate, and 5.50 kg of ion-exchanged water were charged, and the mixture was gradually heated to 245°C over 3 hours while passing nitrogen through it at normal pressure. After distilling out 9.77 kg of water and 0.28 kg of NMP, the reaction vessel was cooled to 200°C. The amount of water remaining in the system per mole of charged alkali metal sulfide was 1.06 mol, including the water consumed in the hydrolysis of NMP. The amount of hydrogen sulfide scattered was 0.02 mol per mole of charged alkali metal sulfide.

[0126] After that, it was cooled to 200°C, 10.42 kg (70.86 mol) of p-dichlorobenzene and 9.37 kg (94.50 mol) of NMP were added, the reaction vessel was sealed under nitrogen gas, and the temperature was raised from 200°C to 270°C at a rate of 0.6°C / min while stirring at 240 rpm, and the reaction was carried out at 270°C for 140 minutes. Then, 2.40 kg (133 mol) of water was injected while cooling from 270°C to 250°C over 15 minutes. Then, it was gradually cooled from 250°C to 220°C over 75 minutes, and then quenched to near room temperature and the contents were taken out. The contents were diluted with 35 liters of NMP to form a slurry, which was stirred at 85°C for 30 minutes, and then filtered through an 80 mesh wire net (opening 0.175 mm) to obtain a solid.

[0127] The obtained solid was washed and filtered with 35 liters of NMP in the same manner. The obtained solid was diluted with 70 liters of ion-exchanged water, stirred at 70°C for 30 minutes, and then filtered through an 80 mesh wire mesh to recover the solid. This operation was repeated three times in total. The obtained solid and 32 g of calcium acetate were diluted with 70 liters of ion-exchanged water, stirred at 70°C for 30 minutes, filtered through an 80 mesh wire mesh, and the obtained solid was further diluted with 70 liters of ion-exchanged water, stirred at 70°C for 30 minutes, and then filtered through an 80 mesh wire mesh to recover the solid.

[0128] The solid thus obtained was dried at 120° C. under a nitrogen stream to obtain a dried PPS-3. The obtained PPS-3 had an MFR of 600 g / 10 min.

[0129] [Reference Example 4] PPS-4 In a 70-liter autoclave equipped with a stirrer and a bottom plug valve, 8.27 kg (70.00 mol) of 47.5% sodium hydrosulfide, 2.91 kg (69.80 mol) of 96% sodium hydroxide, 11.45 kg (115.50 mol) of N-methyl-2-pyrrolidone (NMP), 1.89 kg (23.10 mol) of sodium acetate, and 10.5 kg of ion-exchanged water were charged, and the mixture was gradually heated to 245°C over about 3 hours while passing nitrogen through it at normal pressure. After distilling out 14.78 kg of water and 0.28 kg of NMP, the reaction vessel was cooled to 200°C. The amount of water remaining in the system per mole of charged alkali metal sulfide was 1.06 mol, including the water consumed in the hydrolysis of NMP. The amount of hydrogen sulfide scattered was 0.02 mol per mole of charged alkali metal sulfide.

[0130] The mixture was then cooled to 200°C, 10.45 kg (71.07 mol) of p-dichlorobenzene and 9.37 kg (94.50 mol) of NMP were added, the reaction vessel was sealed under nitrogen gas, and the temperature was increased from 200°C to 270°C at a rate of 0.6°C / min while stirring at 240 rpm. After reacting for 100 minutes at 270°C, the bottom plug valve of the autoclave was opened, and the contents were flushed into a vessel equipped with a stirrer over 15 minutes while pressurizing with nitrogen, and most of the NMP was removed by stirring for a while at 250°C.

[0131] The obtained solid matter and 76 L of ion-exchanged water were placed in an autoclave equipped with a stirrer, washed at 70° C. for 30 minutes, and then suction filtered through a glass filter. Next, 76 L of ion-exchanged water heated to 70° C. was poured into the glass filter, and suction filtered to obtain a cake.

[0132] The obtained cake and 90 liters of ion-exchanged water were charged into an autoclave equipped with a stirrer, and acetic acid was added to adjust the pH to 7. After the inside of the autoclave was replaced with nitrogen, the temperature was raised to 192°C and maintained at that temperature for 30 minutes. The autoclave was then cooled and the contents were removed.

[0133] The contents were filtered with a glass filter under suction, and then 76 liters of ion-exchanged water at 70° C. was poured therein and filtered under suction to obtain a cake. The obtained cake was dried at 120° C. under a nitrogen stream to obtain a dried PPS.

[0134] The obtained PPS was heat-treated at 200° C. in an oxygen stream until the MFR of the obtained PPS reached 140 g / 10 min, to obtain PPS-4.

[0135] The raw materials used in the examples and comparative examples are shown below. (B) Carbon nanotubes B-1: Carbon nanotubes (Kumho 210T, CNT diameter 11-13 nm, specific surface area 250-280 m 2 / g, carbon purity 95%) (C) Irregular cross-section glass fiber C-1: Flat glass fiber T760FGF: Flatness 4.0, short diameter 6μm, long diameter 24μm (D) Inorganic filler D1-1: Glass fiber (T-760H manufactured by Nippon Electric Glass Co., Ltd., average fiber diameter 10.5 μm) D1-2: Glass fiber (T-717H manufactured by Nippon Electric Glass Co., Ltd., average fiber diameter 13.0 μm) D2-1: Heavy calcium carbonate (Escalon #800, manufactured by Sankyo Flour Milling Co., Ltd.) D2-2: Heavy calcium carbonate (KSS-1000, manufactured by Calfine Co., Ltd.) (E) Elastomer E-1-1: Ethylene-glycidyl methacrylate-methyl acrylate copolymer (Sumitomo Chemical Co., Ltd., Bondfast 7M, 67% by weight of ethylene, 6% by weight of glycidyl methacrylate, 27% by weight of methyl acrylate) E-2-1(a): Ethylene-n-butyl acrylate copolymer (Lotril 35BA40, manufactured by Arkema Co., Ltd.) (F) Carbon black F-1:2300B (manufactured by Mitsubishi Chemical Corporation).

[0136] [Method of measuring and evaluating molded products made from resin composition] The measurement and evaluation methods in the present examples and comparative examples are as follows.

[0137] (1) Tensile properties (tensile strength and tensile strain) The resin composition pellets were fed to an injection molding machine (SE-50D) manufactured by Sumitomo Heavy Industries, Ltd., with a cylinder temperature of 310°C and a mold temperature of 145°C, and injection molded using a mold with a type A1 test piece shape as specified in ISO 20753 (2008) under conditions of a filling time of 0.8 s and a pressure retention of 75% of the filling pressure to obtain a test piece for evaluation. The test piece was conditioned for 16 hours under conditions of 23°C and 50% relative humidity, and then the tensile strength and tensile strain were measured in accordance with ISO 527-1, -2 (2012) under conditions of an atmosphere of 23°C and 50% relative humidity, a gripper distance of 115 mm, and a test speed of 5 mm / min. The higher the tensile strength and tensile strain, the better the mechanical strength and the more preferable it is.

[0138] (2) Mold shrinkage rate A molded product having a square plate shape (80mm x 80mm x 2.0mmt) shown in FIG. 1 was molded using a Sumitomo Heavy Industries injection molding machine (SE-100DU). The molding conditions were a cylinder temperature of 320°C, a mold temperature of 130°C, and other conditions were general molding conditions. The dimensions of the molded product in the MD and TD directions were measured at three points, and the average value was calculated. The mold shrinkage rate was determined by subtracting the average value from the actual dimensions of the mold and dividing the result by the actual dimensions of the mold. The measurement was performed using a Mitutoyo three-dimensional dimension measuring machine in accordance with JIS B0621. The dimensional accuracy was determined by subtracting the mold shrinkage rate in the MD direction from the mold shrinkage rate in the TD direction. The smaller the difference in the mold shrinkage rate between the MD and TD directions, the better the low anisotropy (the anisotropy is small), and the more preferable it is.

[0139] (3) S-parameters The resin composition pellets were fed to an injection molding machine (SE50DUZ-C160) manufactured by Sumitomo Heavy Industries, Ltd., with the cylinder temperature set at 320°C and the mold temperature set at 130°C, and injection molding was performed using a mold for a flat plate (80mm x 80mm x 2.0mmt) under the conditions of a filling time of 0.5s and a pressure holding time of 50% of the filling pressure to obtain a square plate (80mm x 80mm x 2.0mmt). Using this test piece, the S parameters were measured using the free space method. The vector network analyzer used was ME7838A manufactured by Anritsu Corporation, and the measurement frequency range was set to 60 to 90GHz. S11, which represents the reflection performance, and S21, which represents the absorption performance, were measured. During the measurement, the square plate was set so that the resin flow direction (MD) was perpendicular to the measuring device installation surface, and the measured value was taken as S21[MD]. The square plate was then rotated 90 degrees (set so that the direction perpendicular to the resin flow direction (TD) of the square plate was perpendicular to the measuring device installation surface), and the measured value was taken as S21[TD]. Furthermore, it is preferable that the ratio of S21[TD] to S21[MD], S21[TD] / S21[MD], is 0.70 to 0.90.

[0140] [Examples 1 to 5, Comparative Examples 1 to 4] Using a twin-screw extruder (TEM-26SS manufactured by Toshiba Machine Co., Ltd.) with a 26 mm diameter intermediate addition port set at a cylinder temperature of 320°C and a screw rotation speed of 400 rpm, (B) CNT and, if necessary, (D) inorganic filler, (E) elastomer and (F) carbon black were added from the raw material supply port in the weight ratios shown in Table 1 to 100 parts by weight of (A) PPS resin obtained in Reference Examples 1 to 4 to make it in a molten state, (C) modified cross-section glass fiber was supplied from the intermediate addition port in the weight ratios shown in Table 1, melt-kneaded at a discharge rate of 30 kg / hour, and extruded so that the temperature of the resin discharged from the die was 360°C or less to obtain PPS resin composition pellets. The above-mentioned properties were evaluated using these PPS resin composition pellets. The results are shown in Table 1.

[0141] [Table 1]

[0142] In Examples 1 to 5, by using (B) CNT and mixing the components (A) to (C) in the prescribed amounts, the anisotropy of the electromagnetic wave absorption performance was reduced while maintaining high mechanical properties.

[0143] In Examples 2 to 4, by increasing the amount of (C) modified cross section glass fiber used, the anisotropy of the electromagnetic wave absorbing performance became smaller.

[0144] In Example 1 and Comparative Examples 1 and 2, (B) CNT is not blended, and therefore it is understood that there is no electromagnetic wave absorption property. In Example 1 and Comparative Example 4, the use of the modified cross section glass fiber (C) resulted in a decrease in the anisotropy of the electromagnetic wave absorbing performance. [Industrial Applicability]

[0145] The resin composition of the present invention has small anisotropy in electromagnetic wave absorption properties without significantly impairing the excellent mechanical strength and flame retardancy that are inherent to PPS resin. Therefore, when applied to electrical and electronic components and automotive and vehicle-related components, where leakage of electromagnetic noise is undesirable, it can reduce leakage of electromagnetic noise around the components. [Explanation of symbols]

[0146] 1 Gate position when molding test sample (film gate) 2 Antenna Port 1 3. Dielectric Lens 4. Sample Holder 5. Dielectric Lens 6 Antenna Port 2 7. Test Samples

Claims

1. A polyphenylene sulfide resin composition comprising (A) 100 parts by weight of polyphenylene sulfide resin, (B) 0.5 parts by weight or more and 15 parts by weight or less of carbon nanotubes, and (C) 20 parts by weight or more and 200 parts by weight or less of irregular cross section glass fibers.

2. The carbon nanotubes (B) have a purity of 90% by weight or more and a specific surface area of ​​190 m ２ / g or more 300m ２ The polyphenylene sulfide resin composition according to claim 1, wherein the molecular weight of the polyphenylene sulfide resin composition is 1000 or less.

3. The polyphenylene sulfide resin composition according to claim 1 or 2, characterized in that the ratio of the major axis (the longest linear distance of the cross section) to the minor axis (the longest linear distance perpendicular to the major axis) of the modified cross section glass fiber (C) is 1.3 to 10.

4. The polyphenylene sulfide resin composition according to claim 1 or 2, characterized in that 0.1 parts by weight or more and 150 parts by weight or less of (D) an inorganic filler other than the modified cross section glass fiber (C) is further blended with respect to 100 parts by weight of the polyphenylene sulfide resin (A).

5. 3. The polyphenylene sulfide resin composition according to claim 1, further comprising (F) 0.5 parts by weight or more and 3.0 parts by weight or less of carbon black per 100 parts by weight of the polyphenylene sulfide resin (A).

6. 3. The method for producing a polyphenylene sulfide resin composition according to claim 1, wherein the polyphenylene sulfide resin (A), the carbon nanotubes (B) and the modified cross section glass fibers (C) are melt-kneaded at a resin temperature of 360° C. or less.

7. A molded article comprising the polyphenylene sulfide resin composition according to claim 1 or 2.

8. The molded article according to claim 7 , which is an electromagnetic wave absorber.

Images