Polyamide resin composition and molded article

Abstract

To provide a polyamide resin composition having superior thermal conductivity, flowability, and flame retardancy without significantly impairing the intrinsic mechanical strength of the polyamide resin, including tensile strength, impact strength, and tracking resistance, and a molded article, wherein the inventive polyamide resin composition has superior heat cycle resistance in addition to these characteristics, making it suitable for metal insert molded products.SOLUTION: A polyamide resin composition comprises, per 100 pts.wt. of a polyamide resin (A), 60 to 170 pts.wt. of magnesium hydroxide (B), 60 to 170 pts.wt. of an inorganic fibrous filler (C), and 5 to 35 pts.wt. of a phosphazene compound (D).SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a polyamide resin composition and a molded article. [Background technology]

[0002] In electric vehicles, the heat generated by batteries and motors is increasing due to higher battery capacity and motor output, which in turn increases the heat generated by electrical components through which high-voltage current flows, such as inverters and direct current-direct current (hereinafter referred to as DC-DC) converters.In addition, to save space and improve efficiency, motors are being considered for integration with gears and inverters, as well as DC-DC converters, power distribution units, positive temperature coefficient heaters, on-board chargers, etc.

[0003] As an example of a heat-dissipating resin composition, Patent Document 1 describes a resin composition obtained by blending magnesium hydroxide and glass fiber with a polyamide resin.

[0004] Furthermore, as an example of a flame-retardant resin composition, Patent Document 2 describes a resin composition obtained by blending a crosslinked phosphazene, an inorganic fibrous material, and magnesium hydroxide with a polyamide resin. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Patent No. 6079490 [Patent Document 2] Japanese Patent Application Laid-Open No. 2001-131409 Summary of the Invention [Problem to be solved by the invention]

[0006] In electric vehicle motors, commonly known as electric axles, the increase in heat generation and space-saving design pose a problem of increasing the ambient temperature of the entire system. When applying resin compositions to automotive parts, high thermal conductivity is required to suppress the increase in ambient temperature. However, polyamide resins do not inherently possess high thermal conductivity.

[0007] In addition, there is a growing demand for thinner automotive parts to reduce weight, but the thinner the wall of a resin molded product, the more likely it is that its mechanical strength and flame retardancy will decrease, and so resin compositions with improved properties are required.However, polyamide resins have inferior flame retardancy compared to other engineering plastics such as PPS resins.

[0008] Furthermore, as electric vehicles become more powerful, their rated voltages tend to rise, so there is a demand for resin molded products that can withstand tracking breakdown that occurs when high voltage is applied to the surface of the insulator.

[0009] In addition, since they are often used in automotive applications as metal insert parts, heat cycle resistance is also required in addition to the above properties. A commonly known method for improving toughness is to add elastomers, but adding elastomers makes them more flammable, making it difficult to achieve both heat cycle resistance and flame retardancy.

[0010] To address the above-mentioned issues, the resin composition disclosed in Patent Document 1 has improved thermal conductivity but insufficient flame retardancy, and there is no mention of the heat cycle resistance of the resin composition.

[0011] Furthermore, although the resin composition disclosed in Patent Document 2 has improved flame retardancy, it is presumed that its mechanical strength and thermal conductivity are insufficient. Furthermore, there is no mention of the heat cycle resistance of the resin composition.

[0012] An object of the present invention is to provide a polyamide resin composition which overcomes the drawbacks of the prior art and a molded article made using the same. [Means for solving the problem]

[0013] The present inventors have conducted extensive research to solve the above problems and have arrived at the present invention. (1) A polyamide resin composition comprising 100 parts by weight of (A) polyamide resin, 60 to 170 parts by weight of (B) magnesium hydroxide, 60 to 170 parts by weight of (C) inorganic fibrous filler, and 5 to 35 parts by weight of (D) a phosphazene compound. (2) The polyamide resin composition according to (1) above, wherein the amount of the phosphazene compound (D) blended is 10 to 25 parts by weight. (3) The polyamide resin composition according to (1) or (2) above, wherein the average primary particle size of the magnesium hydroxide (B) is 0.1 μm to 10 μm. (4) The polyamide resin composition according to (1) or (2) above, wherein the loose bulk density of the magnesium hydroxide (B) is 0.3 g / mL or more. (5) The polyamide resin composition according to (1) or (2) above, wherein the (A) polyamide resin comprises a polyamide 66 / 6I / 6 copolymer and / or a 66 / 6I copolymer. (6) The polyamide resin composition according to (1) or (2) above, wherein the polyamide resin (A) is a polyamide 66 / 6I / 6 copolymer. (7) A molded article made of the polyamide resin composition according to (1) or (2) above. (8) The molded article according to (7) above, wherein the molded article has a thermal conductivity of 0.8 W / (m·K) or more as measured by the hot disc method in accordance with ISO22007-2. (9) The molded article according to (7) above, wherein the flammability of the molded article measured by a method conforming to UL94 is V-0 for a test piece having a thickness of 1.5 mm or less. (10) The molded article according to (7) above, wherein the molded article has a tracking resistance of 600 V or more as measured by a method in accordance with IEC 60112 (2003). [Effects of the Invention]

[0014] The present invention can provide a polyamide resin composition and a molded article thereof that are excellent in thermal conductivity, flowability, and flame retardancy without significantly impairing the excellent mechanical strength inherent to polyamide resins, i.e., tensile strength, impact strength, and tracking resistance. Furthermore, the polyamide resin composition of the present invention has excellent heat cycle resistance while maintaining the above-mentioned properties, and is therefore suitable for use in metal insert molded articles. DETAILED DESCRIPTION OF THE INVENTION

[0015] Hereinafter, embodiments of the present invention will be described in detail.

[0016] The polyamide resin composition of the present invention is obtained by blending 60 to 170 parts by weight of (B) magnesium hydroxide, 60 to 170 parts by weight of (C) inorganic fibrous filler, and 5 to 35 parts by weight of (D) phosphazene compound with 100 parts by weight of (A) polyamide resin. In the present invention, the (A) polyamide resin may be simply referred to as component (A). The same applies to the other components.

[0017] Each component will be described below.

[0018] (A) Polyamide resin The polyamide resin (A) used in the present invention is a resin in which the content of repeating units obtained by polymerizing one or more raw materials selected from the group consisting of (i) amino acids, (ii) lactams, and (iii) diamines and dicarboxylic acids is 70 mol % or more of the total repeating units, preferably 90 mol % or more, and more preferably 100 mol %. Typical examples of raw materials for (A) polyamide resins include amino acids such as 6-aminocaproic acid, 11-aminoundecanoic acid, 12-aminododecanoic acid, and para-aminomethylbenzoic acid; lactams such as ε-caprolactam and ω-laurolactam; aliphatic diamines such as tetramethylenediamine, pentamethylenediamine, hexamethylenediamine, 2-methylpentamethylenediamine, nonamethylenediamine, decamethylenediamine, undecamethylenediamine, dodecamethylenediamine, 2,2,4- / 2,4,4-trimethylhexamethylenediamine, 5-methylnonamethylenediamine, and 2-methyloctamethylenediamine; aromatic diamines such as metaxylylenediamine and paraxylylenediamine; 1,3-bis(aminomethyl)cyclohexane, 1,4-bis(aminomethyl)cyclohexane, 1-amino-3-aminomethyl-3,5,5-tri ... alicyclic diamines such as trimethylcyclohexane, bis(4-aminocyclohexyl)methane, bis(3-methyl-4-aminocyclohexyl)methane, 2,2-bis(4-aminocyclohexyl)propane, bis(aminopropyl)piperazine, and aminoethylpiperazine; aliphatic dicarboxylic acids such as adipic acid, suberic acid, azelaic acid, sebacic acid, and dodecanedioic acid; aromatic dicarboxylic acids such as terephthalic acid, isophthalic acid, 2-chloroterephthalic acid, 2-methylterephthalic acid, 5-methylisophthalic acid, 5-sodium sulfoisophthalic acid, 2,6-naphthalenedicarboxylic acid, hexahydroterephthalic acid, and hexahydroisophthalic acid; and alicyclic dicarboxylic acids such as 1,4-cyclohexanedicarboxylic acid, 1,3-cyclohexanedicarboxylic acid, 1,2-cyclohexanedicarboxylic acid, and 1,3-cyclopentanedicarboxylic acid.In an embodiment of the present invention, two or more kinds of polyamide homopolymers or polyamide copolymers derived from these raw materials may be blended as raw materials for the (A) polyamide resin.

[0019] In the present invention, the melting point of the (A) polyamide resin is preferably 200 to 300°C. The melting point is defined as the temperature of the endothermic peak that appears when, using a differential scanning calorimeter (DSC), the resin is cooled from a molten state to 20°C at a rate of 20°C / min under a nitrogen atmosphere, maintained at that temperature for 2 minutes, and then heated at a rate of 20°C / min. When multiple polyamide resins with different melting points are used in combination, the melting point is that of the polyamide resin with the highest melting point. The heat resistance of the polyamide resin composition can be improved by incorporating an (A) polyamide resin with a melting point of 200°C or higher. For example, when an electrode is connected to an electrical or electronic component such as a connector and electricity is applied for a long period of time, the temperature may reach approximately 200°C. However, the use of a highly heat-resistant polyamide resin composition can suppress thermal degradation of the electrical or electronic component and improve drop resistance after prolonged use. The melting point of the (A) polyamide resin is more preferably 220°C or higher. On the other hand, by setting the melting point of (A) polyamide resin to 300°C or less, deterioration of (A) polyamide resin and dehydration reaction of magnesium hydroxide can be suppressed during melt-kneading and injection molding, thereby suppressing the formation of voids in electric / electronic parts produced by injection molding the thermoplastic resin composition, and further improving the filling rate and thermal conductivity of the molded product. It is more preferable that the melting point of (A) polyamide resin be 280°C or less.

[0020] Specific examples of (A) polyamide resins include polycaproamide (nylon 6), polyhexamethylene adipamide (nylon 66), polytetramethylene adipamide (nylon 46), polytetramethylene sebacamide (nylon 410), polypentamethylene adipamide (nylon 56), polypentamethylene sebacamide (nylon 510), polyhexamethylene sebacamide (nylon 610), polyhexamethylene dodecamide (nylon 612), polydecamethylene adipamide (nylon 106), and polydecamethylene sebacamide (nylon 1010). , Polydecamethylene dodecamide (Nylon 1012), Polyundecaneamide (Nylon 11), Polydodecanamide (Nylon 12), Polycaproamide / Polyhexamethylene adipamide copolymer (Nylon 6 / 66), Polycaproamide / Polyhexamethylene terephthalamide copolymer (Nylon 6 / 6T), Polyhexamethylene adipamide / Polyhexamethylene terephthalamide copolymer (Nylon 66 / 6T), Polyhexamethylene adipamide / Polyhexamethylene isophthalamide copolymer (Nylon 66 / 6I), Polyhexamethylene Polyhexamethylene adipamide / polyhexamethylene isophthalamide / polycaproamide copolymer (nylon 66 / 6I / 6), polyhexamethylene terephthalamide / polyhexamethylene isophthalamide copolymer (nylon 6T / 6I), polyhexamethylene terephthalamide / polyundecane amide copolymer (nylon 6T / 11), polyhexamethylene terephthalamide / polydodecanamide copolymer (nylon 6T / 12), polyhexamethylene adipamide / polyhexamethylene terephthalamide / polyhexamethylene isophthalamide copolymer -(Nylon 66 / 6T / 6I), Polyxylylene adipamide (Nylon XD6), Polyxylylene sebacamide (Nylon XD10), Polyhexamethylene terephthalamide / Polypentamethylene terephthalamide copolymer (Nylon 6T / 5T), Polyhexamethylene terephthalamide / Poly-2-methylpentamethylene terephthalamide copolymer (Nylon 6T / M5T), Polypentamethylene terephthalamide / Polydecamethylene terephthalamide copolymer (Nylon 5T / 10T), Polynonamethylene terephthalamide (Nylon 9T),Examples of polyamide resins include polydecamethylene terephthalamide (nylon 10T) and polydodecamethylene terephthalamide (nylon 12T). Specific examples of polyamide resins include mixtures and copolymers of these. Here, " / " indicates a copolymer. The same applies hereinafter. It is practically suitable to blend two or more of these polyamide resins depending on the required properties, such as mechanical properties, fluidity, mold releasability, surface appearance, and heat resistance.

[0021] Among these, polyamide 6 / 66, polyamide 66 / 6I, polyamide 66 / 6I / 6, polyamide 6T / 6I, polyamide 6T / 12, polyamide 66 / 6T / 6I, polyamide MXD6, polyamide 6T / M5T, polyamide 9T / M8T, polyamide 10T / 66, and polyamide 10T / 612 are preferably used because they exhibit a good balance of properties such as mechanical strength, heat cycle resistance, shear rate dependence of melt viscosity, mold release properties during molding, surface appearance of molded products, and heat resistance. In the polyamide resin composition of the present invention, it is more preferable that the (A) polyamide resin comprises a polyamide 66 / 6I / 6 copolymer and / or a polyamide 66 / 6I copolymer, and most preferably a polyamide 66 / 6I / 6 copolymer.

[0022] The polyamide 66 / 6I / 6 content in the (A) polyamide resin is preferably 70 to 100 parts by weight per 100 parts by weight of the total. If the content of polyamide 66 / 6I / 6 in the (A) polyamide resin is 70 parts by weight or more, a better balance of properties such as mechanical strength, extrusion processability, fluidity, shear rate dependency of melt viscosity, mold releasability during molding, surface appearance of molded products, and heat resistance can be achieved. 80 parts by weight or more is more preferable.

[0023] Although there are no particular limitations on the degree of polymerization of (A) polyamide resin, it is preferable that the viscosity number measured in a 96% (mass fraction) sulfuric acid solution in accordance with ISO 307 is 70 to 140 ml / g. If the viscosity number is 70 ml / g or higher, the mechanical strength of the resulting molded article can be further improved. On the other hand, if the viscosity number is 140 ml / g or lower, the extrusion processability and flowability can be improved. It is more preferable that the viscosity number is 100 ml / g or lower.

[0024] The total amount of components (A) to (D) blended is preferably 60% by weight or more, and more preferably 90% by weight or more, based on 100% by weight of the resin composition.

[0025] (B) Magnesium hydroxide The polyamide resin composition of the present invention is prepared by blending 60 to 170 parts by weight of (B) magnesium hydroxide with 100 parts by weight of (A) polyamide resin. By blending such magnesium hydroxide, the thermal conductivity of the polyamide resin composition can be improved and flame retardancy can be imparted. The blend amount of (B) magnesium hydroxide is 60 parts by weight or more, and preferably more than 80 parts by weight. The blend amount of (B) magnesium hydroxide is 170 parts by weight or less, and preferably 150 parts by weight or less. If the blend amount is less than 60 parts by weight with respect to 100 parts by weight of (A) polyamide resin, the thermal conductivity and flame retardancy decrease. If the blend amount exceeds 170 parts by weight, the mechanical strength decreases and extrusion processability also tends to decrease.

[0026] In the present invention, (B) magnesium hydroxide preferably contains 80 parts by weight or more of an inorganic substance represented by the chemical formula Mg(OH)2. By containing 80 parts by weight or more of the inorganic substance, the thermal conductivity and flame retardancy of the polyamide resin composition can be further improved.

[0027] The shape of (B) magnesium hydroxide may be any of particles, flakes, and fibers, but particles and flakes are preferred from the viewpoint of transportability and dispersibility of the raw material during extrusion melt kneading.

[0028] In the polyamide resin composition of the present invention, the average primary particle diameter of (B) magnesium hydroxide is not particularly limited. However, from the viewpoint of further improving the mechanical strength, thermal conductivity, and extrusion processability of the polyamide resin composition, the average primary particle diameter of (B) magnesium hydroxide is preferably 0.1 μm to 10 μm, and more preferably 0.3 μm to 4 μm.

[0029] In the polyamide resin composition of the present invention, the loose bulk density of (B) magnesium hydroxide is not particularly limited, but from the viewpoint of improving the transportability of raw materials during extrusion melt-kneading, the loose bulk density of (B) magnesium hydroxide is preferably 0.3 g / mL or more. The upper limit of the loose bulk density is not particularly limited, but is usually about 2.0 g / mL, more preferably 1.5 g / mL.

[0030] (B) Magnesium hydroxide may be surface-treated with, for example, a vinyl silane compound such as vinyl triethoxysilane or vinyl trichlorosilane; an epoxy silane compound such as γ-glycidoxypropyl trimethoxysilane, γ-glycidoxypropyl triethoxysilane, or β-(3,4-epoxycyclohexyl)ethyl trimethoxysilane; an amino silane compound such as γ-(2-aminoethyl)aminopropyl methyl dimethoxysilane, γ-(2-aminoethyl)aminopropyl trimethoxysilane, or γ-aminopropyl trimethoxysilane; a long-chain fatty acid or long-chain aliphatic alcohol such as stearic acid, oleic acid, montanic acid, or stearyl alcohol;

[0031] (C) Inorganic fibrous filler The polyamide resin composition of the present invention is obtained by blending 60 to 170 parts by weight of (C) inorganic fibrous filler with 100 parts by weight of (A) polyamide resin. The blending amount of (C) inorganic fibrous filler is 60 parts by weight or more, and preferably more than 80 parts by weight. The blending amount of (C) inorganic fibrous filler is 170 parts by weight or less, and preferably 150 parts by weight or less. If the blending amount is less than 60 parts by weight per 100 parts by weight of (A) polyamide resin, mechanical strength decreases, and if the blending amount is more than 170 parts by weight, extrusion processability decreases.

[0032] The inorganic fibrous filler (C) is not particularly limited, and known fillers can be used. By blending glass fibers with the polyamide resin composition of the present invention, it is possible to improve the mechanical strength, mold releasability, and heat resistance.

[0033] (C) Examples of inorganic fibrous fillers include glass fibers, carbon fibers, potassium titanate whiskers, zinc oxide whiskers, aluminum borate whiskers, alumina fibers, silicon carbide fibers, ceramic fibers, asbestos fibers, gypsum fibers, and metal fibers, which may be hollow. Two or more of these inorganic fibrous fillers can also be used in combination. These inorganic fibrous fillers may also be pretreated with a coupling agent such as an isocyanate compound, an organosilane compound, an organotitanate compound, an organoborane compound, or an epoxy compound, which can further improve the load during high-speed compression.

[0034] Among the inorganic fibrous fillers, glass fiber and carbon fiber are preferred. Glass fiber is more preferably used because it facilitates the development of high-load rectangular waves during high-speed compression of a prismatic molded article.

[0035] The glass fibers used in the present invention are not particularly limited, and known glass fibers can be used. Glass fibers are available in the form of chopped strands cut to a predetermined length, roving strands, milled fibers, etc., and generally, those with an average fiber diameter of 5 to 15 μm are preferably used. When using chopped strands, there are no particular restrictions on the fiber length, but glass fibers with a strand length of 3 mm are preferably used, as they have high extrusion kneading workability. When using roving strands, they can be composited by a known technique of directly feeding the roving strands into an extruder. Two or more of these glass fibers may be used in combination.

[0036] The carbon fiber used in the present invention is not particularly limited, and various known carbon fibers can be used, such as carbonaceous fibers and graphite fibers produced using polyacrylonitrile (PAN), pitch, rayon, lignin, hydrocarbon gas, etc., and fibers obtained by coating these fibers with metal. Among these, PAN-based carbon fibers, which can improve mechanical properties, are preferred. Carbon fibers are usually available in the form of chopped strands cut to a predetermined length, roving strands, milled fibers, etc., and have a diameter of 15 μm or less, preferably 5 to 10 μm. When using chopped strands, there are no particular restrictions on the fiber length, but it is preferable to use strands with a length that facilitates extrusion kneading. When using roving strands, they can be compounded using a known technique of directly feeding the roving strands into an extruder. In the present invention, chopped strands are preferably used, and the number of filaments in the carbon fiber strands, which are precursors to chopped carbon fibers, is preferably 1,000 to 150,000 from the viewpoints of production cost and stability in the production process.

[0037] (D) Phosphazene Compounds The polyamide resin composition of the present invention is prepared by blending 5 to 35 parts by weight of (D) a phosphazene compound with 100 parts by weight of (A) a polyamide resin. By blending such a phosphazene compound, a polyamide resin excellent in impact strength, flame retardancy, and fluidity can be provided. Furthermore, improved impact strength suppresses cracking during heat cycles, and improved fluidity reduces residual stress during molding, thereby improving the heat cycle resistance of molded articles. Heat cycle resistance is measured by the method described below.

[0038] In the present invention, the phosphazene compound (D) refers to a compound having a -P=N- bond in the molecule, such as a cyclic phosphazene compound having the structure represented by the following structural formula (1).

[0039] [ka]

[0040] In the above general formula (1), n ​​represents an integer of 1 to 1000. R1 and R2 each independently represent a hydrogen atom, a linear, branched, or cyclic alkyl group having from 1 to 18 carbon atoms, a linear, branched, or cyclic alkoxyl group having from 1 to 30 carbon atoms, an aryl group having from 6 to 30 carbon atoms, or an aryloxy group having from 6 to 30 carbon atoms.

[0041] In the above general formula (1), examples of the alkyl group include a methyl group and an ethyl group. Examples of the alkoxyl group include a methoxy group and an ethoxy group. Examples of the aryl group include a phenyl group. Examples of the aryloxy group include a phenyloxy group. n is preferably 3 to 30, and the compound preferably contains at least a cyclic phosphazene compound in which the structure represented by the above general formula (1) is cyclically bonded.

[0042] The phosphazene compound (D) may also be a crosslinked phosphazene compound. Such a crosslinked phosphazene compound can be obtained, for example, by crosslinking a linear or cyclic phosphazene compound represented by the above general formula (1) via a divalent crosslinking group, and examples of such a crosslinked phosphazene compound include phosphazene compounds having a structure represented by the following general formula (2):

[0043] [ka]

[0044] In the above general formula (2), m and o represent integers of 1 to 1000. R3 and R4 each independently represent a hydrogen atom, a linear, branched, or cyclic alkyl group having from 1 to 18 carbon atoms, a linear, branched, or cyclic alkoxyl group having from 1 to 30 carbon atoms, an aryl group having from 6 to 30 carbon atoms, or an aryloxy group having from 6 to 30 carbon atoms. X represents a divalent bridging group.

[0045] In the above general formula (2), examples of the alkyl group include a methyl group and an ethyl group. Examples of the alkoxyl group include a methoxy group and an ethoxy group. Examples of the aryl group include a phenyl group. Examples of the aryloxy group include a phenyloxy group.

[0046] In the above general formula (2), X represents a divalent crosslinking group, and examples of the crosslinking group include a dialkoxybenzene group (o-dialkoxybenzene group, m-dialkoxybenzene group, p-dialkoxybenzene group) represented by the structure -O-C6H4-O-, and a bisphenylene group represented by the following general formula (3). The divalent crosslinking group can be used alone or in combination of two or more. The above crosslinked phosphazene compound can be obtained, for example, by the method described in Examples 1 to 7 of JP-A 2003-192792 or other known methods.

[0047] [ka]

[0048] In general formula (3), A represents a direct bond, -C(CH3)2-, -SO2-, -S- or -O-.

[0049] (D) The phosphazene compound may be synthesized or commercially available. Phosphazene compounds can be synthesized by known methods, such as those described in "Synthesis and Applications of Phosphazene Compounds" (by Kajiwara Naruyuki, CMC Publishing, 1986). For example, phosphorus pentachloride or phosphorus trichloride as a phosphorus source and ammonium chloride or ammonia gas as a nitrogen source can be reacted by a known method, or the resulting cyclic product can be purified and the resulting substance can be substituted with an alcohol, phenol, and amines. Commercially available products such as "HPCTP" (manufactured by HighChem Co., Ltd.) are preferably used.

[0050] As described above, the polyamide resin composition of the present invention contains 5 to 35 parts by weight of the (D) phosphazene compound. The amount of the (D) phosphazene compound is preferably 10 to 25 parts by weight. The lower limit of the amount of the (D) phosphazene compound must be 5 parts by weight or more, and preferably more than 10 parts by weight, per 100 parts by weight of the (A) polyamide resin. The upper limit must be 35 parts by weight or less, and preferably 25 parts by weight or less. If the amount is less than 5 parts by weight per 100 parts by weight of the (A) polyamide resin, flame retardancy and flowability will decrease. If the amount is more than 35 parts by weight, thermal decomposition will occur during extrusion melt-kneading and injection molding, and the viscosity will decrease, resulting in decreased extrusion processability and meterability during injection molding, as well as decreased flame retardancy and heat cycle resistance.

[0051] The polyamide resin composition of the present invention may contain components other than the components (A) to (D) as needed, provided that the properties of the composition are not impaired.

[0052] For example, if necessary, a thermoplastic resin other than the (A) polyamide resin may be blended within a range that does not impair the properties. Examples of thermoplastic resins other than the (A) polyamide resin include polyester resins, polyphenylene sulfide resins, polyphenylene oxide resins, polycarbonate resins, polylactic acid resins, polyacetal resins, polysulfone resins, tetrafluoroethylene resins, polyetherimide resins, polyamideimide resins, polyimide resins, polyethersulfone resins, polyetherketone resins, polythioetherketone resins, polyetheretherketone resins, polyethylene resins, polypropylene resins, styrene-based resins such as polystyrene resins and ABS resins, and polyalkylene oxide resins. Two or more such thermoplastic resins may also be blended. When such a thermoplastic resin is used, its blending amount is not particularly limited, but is preferably 0.01 to 20 parts by weight per 100 parts by weight of the total of the (A) to (D) components.

[0053] The polyamide resin composition of the present invention may contain a rubbery polymer, if necessary, within the range that does not impair its properties. A rubbery polymer is a polymer whose glass transition temperature is lower than room temperature and in which some of the molecules are bound to each other by covalent bonds, ionic bonds, van der Waals forces, entanglements, etc. Examples of rubbery polymers include polybutadiene, polyisoprene, diene rubbers such as styrene / butadiene random copolymers and block copolymers, hydrogenated products of these block copolymers, acrylonitrile / butadiene copolymers, and butadiene / isoprene copolymers; ethylene / propylene random copolymers and block copolymers; ethylene / butene random copolymers and block copolymers; ethylene / α-olefin copolymers; ethylene / unsaturated carboxylic acid ester copolymers such as ethylene / acrylic acid ester and ethylene / methacrylic acid ester; acrylic acid ester / butadiene copolymers such as butyl acrylate / butadiene copolymer; ethylene / fatty acid vinyl copolymers such as ethylene / vinyl acetate copolymer; ethylene / propylene / ethylidenenorbornene copolymers; ethylene / propylene / non-conjugated diene terpolymers such as ethylene / propylene / hexadiene copolymer; butylene / isoprene copolymers; chlorinated polyethylene; polyamide elastomers; and thermoplastic elastomers such as polyester elastomers. Among these, from the viewpoint of compatibility with (A) polyamide resin, ethylene / unsaturated carboxylic acid ester copolymer is preferably used. As the unsaturated carboxylic acid ester, (meth)acrylic acid ester can be mentioned, and preferably an ester of (meth)acrylic acid and alcohol. Specific examples of (meth)acrylic acid ester include methyl (meth)acrylate, ethyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, stearyl (meth)acrylate, etc.

[0054] The rubbery polymer preferably has a reactive functional group from the viewpoint of reactivity with the (A) polyamide resin. Examples of reactive functional groups include epoxy groups, acid anhydride groups, amino groups, carboxyl groups, carboxyl metal salts, oxazoline groups, hydroxyl groups, isocyanate groups, mercapto groups, and sulfonic acid groups. Two or more of these groups may be present. Among these, epoxy groups, acid anhydride groups, amino groups, carboxyl groups, carboxyl metal salts, and oxazoline groups are preferred because they are highly reactive and less prone to side reactions such as decomposition and crosslinking. Methods for introducing reactive functional groups into the rubbery polymer include commonly known techniques and are not particularly limited. For example, methods such as copolymerizing a monomer having a reactive functional group with a monomer that is a raw material for the rubbery polymer and grafting a compound having a reactive functional group onto the rubbery polymer can be used.

[0055] Two or more types of such rubbery polymers can be blended together. When such rubbery polymers are used, there are no particular restrictions on the amount of the polymer blended, but it is preferably 0.01 to 20 parts by weight per 100 parts by weight of the total of components (A) to (D).

[0056] The polyamide resin composition of the present invention may also contain inorganic fillers other than (C) the inorganic fibrous filler, as needed, provided that their properties are not impaired. Examples of inorganic fillers other than (C) the inorganic fibrous filler include wollastonite, zeolite, sericite, kaolin, mica, clay, pyrophyllite, bentonite, asbestos, talc, metal silicates such as alumina silicate, metal oxides such as alumina, silicon oxide, magnesium oxide, zirconium oxide, and iron oxide, carbonates such as calcium carbonate, magnesium carbonate, and dolomite, metal sulfates such as calcium sulfate and barium sulfate, metal hydroxides such as calcium hydroxide and aluminum hydroxide, and inorganic non-fibrous fillers such as glass beads, ceramic beads, boron nitride, and silicon carbide, which may be hollow. These inorganic fillers may also be pretreated with a coupling agent such as an isocyanate compound, an organosilane compound, an organotitanate compound, an organoborane compound, or an epoxy compound. Two or more of these inorganic fillers may also be used in combination. When such an inorganic filler is used, there are no particular restrictions on the amount of filler added, but it is preferably 0.01 to 20 parts by weight per 100 parts by weight of the total of components (A) to (D).

[0057] Furthermore, various additives may be blended into the polyamide resin composition of the present invention as needed, provided that the properties of the composition are not impaired. Examples of the various additives include nucleating agents, color inhibitors, antioxidants (thermal stabilizers), weathering agents, release agents, plasticizers, lubricants, dye-based colorants, pigment-based colorants, antistatic agents, flame retardants, and foaming agents. Two or more of these may be blended. There are no particular limitations on the amount of additives blended, but a preferred amount is 0.01 to 20 parts by weight per 100 parts by weight of the total of components (A) to (D).

[0058] As the antioxidant (heat stabilizer), hindered phenol compounds, hindered amine compounds, hydroquinone compounds, phosphorus compounds and their substituted derivatives, copper halides, iodide compounds, etc. are preferably used, with hindered phenol compounds and phosphorus compounds being particularly preferred.

[0059] Specific examples of hindered phenol compounds include triethylene glycol-bis[3-t-butyl-(5-methyl-4-hydroxyphenyl)propionate], N,N'-hexamethylenebis(3,5-di-t-butyl-4-hydroxy-hydrocinnamide), N,N'-hexamethylenebis[3-(3,5-di-t-butyl-4-hydroxyphenyl)propionamide], tetrakis[methylene-3-(3',5'-di-t-butyl-4'-hydroxyphenyl)propionate]methane, pentaerythrityl tetrakis[3-(3',5'-di-t-butyl-4'-hydroxyphenyl)propionate], 1,3,5-tris(3,5-di-t-butyl-4-hydroxyphenyl)propionate, dibenzyl)-s-triazine-2,4,6-(1H,3H,5H)-trione, 1,1,3-tris(2-methyl-4-hydroxy-5-t-butylphenyl)butane, 4,4'-butylidenebis(3-methyl-6-t-butylphenol), n-octadecyl-3-(3,5-di-t-butyl-4-hydroxy-phenyl)propionate, 3,9-bis[2-(3-(3-t-butyl-4-hydroxy-5-methylphenyl)propionyloxy)-1,1-dimethylethyl]-2,4,8,10-tetraoxaspiro[5,5]undecane, 1,3,5-trimethyl-2,4,6-tris-(3,5-di-t-butyl-4-hydroxybenzyl)benzene, and the like. Among these, amide-type polymeric hindered phenol type is preferred, and specifically, N,N'-hexamethylenebis[3-(3,5-di-t-butyl-4-hydroxyphenyl)propionamide] is preferably used.

[0060] Specific examples of phosphorus-based compounds include phosphite-based compounds such as bis(2,6-di-t-butyl-4-methylphenyl)pentaerythritol diphosphite, bis(2,4-di-t-butylphenyl)pentaerythritol diphosphite, bis(2,4-di-cumylphenyl)pentaerythritol diphosphite, tris(2,4-di-t-butylphenyl)phosphite, tetrakis(2,4-di-t-butylphenyl)-4,4′-bisphenylene phosphite, di-stearylpentaerythritol diphosphite, and triphenyl phosphite; and 3,5-di-butyl-4-hydroxybenzylphosphonate diethyl ester.

[0061] As the weatherproofing agent, a resorcinol-based compound, a salicylate-based compound, a benzotriazole-based compound, a benzophenone-based compound, a hindered amine-based compound, etc. are preferably used.

[0062] As the release agent, aliphatic alcohols, aliphatic amides, aliphatic bisamides, ethylene bisstearylamides, higher fatty acid esters, etc. are preferably used.

[0063] As the plasticizer, octyl p-oxybenzoate, N-butylbenzenesulfonamide, etc. are preferably used.

[0064] As the dye-based colorant, nigrosine, aniline black, etc. are preferably used.

[0065] As the pigment-based colorant, cadmium sulfide, phthalocyanine, carbon black, etc. are preferably used.

[0066] As the antistatic agent, alkyl sulfate type anionic antistatic agents, quaternary ammonium salt type cationic antistatic agents, nonionic antistatic agents such as polyoxyethylene sorbitan monostearate, betaine type amphoteric antistatic agents, etc. are preferably used.

[0067] The polyamide resin composition of the present invention can be produced by a method such as production in a molten state or production in a solution state, with production in a molten state being preferred from the viewpoint of productivity. For production in a molten state, melt kneading using an extruder, Banbury mixer, kneader, mixing roll, or the like can be used, with melt kneading using an extruder capable of continuous production being preferred from the viewpoint of productivity. Examples of extruders include single-screw extruders, twin-screw extruders, multi-screw extruders such as four-screw extruders, and twin-screw single-screw composite extruders. A combination of these extruders may also be used. From the viewpoint of improving kneading properties, reactivity, and productivity, multi-screw extruders such as twin-screw extruders and four-screw extruders are preferred, with twin-screw extruders being more preferred.

[0068] Examples of melt-kneading methods using a twin-screw extruder include a method in which (A) polyamide resin, (B) magnesium hydroxide, (C) inorganic fibrous filler, (D) phosphazene compound, and, if necessary, components other than components (A) to (D) are premixed, and the premix is ​​fed into a twin-screw extruder whose cylinder temperature is set to the melting point of polyamide resin (A) or higher and melt-kneaded. There are no particular restrictions on the order in which the raw materials are mixed, and any of the following methods may be used: a method in which all raw materials are melt-kneaded by the above method; a method in which some raw materials are melt-kneaded by the above method and then the remaining raw materials are blended and melt-kneaded; or a method in which some raw materials are melt-kneaded while the remaining raw materials are mixed using a side feeder. A preferred method is to feed (A) polyamide resin, (B) magnesium hydroxide, (D) phosphazene compound, and, if necessary, other components other than components (A) to (D) into the base of an extruder (the upstream side is the side where the raw materials are fed, and the downstream side is the side where the molten resin is discharged, at the upstream end of the screw) and melt-knead them, and then feed (C) inorganic fibrous filler into the middle of the extruder using a side feeder and melt-knead them. Another preferred method is to expose the extruder to a vacuum state midway through the extruder to remove any gases that are generated.

[0069] The molded article of the present invention is made from the polyamide resin composition of the present invention.

[0070] The molded article of the present invention can be obtained by melt molding the polyamide resin composition of the present invention by, for example, a conventional molding method (injection molding, extrusion molding, press molding, blow molding, injection press molding, etc.). Among these, molding by injection molding or injection press molding is preferred from the viewpoint of mass productivity, and molding by injection molding is most preferred.

[0071] The molded article of the present invention preferably has a thermal conductivity of 0.8 W / (m·K) or more as measured by the hot disk method in accordance with ISO 22007-2. This makes molded articles made from the polyamide resin composition applicable to products requiring heat dissipation properties in line with the increasing capacity of electric vehicle batteries and the increasing power output of motors. One method for achieving the thermal conductivity within the above range is to increase the amount of magnesium hydroxide, which has heat dissipation properties. While there are no particular limitations on the upper limit of the thermal conductivity, it is typically around 2.5 W / (m·K).

[0072] The molded article of the present invention preferably has a flammability rating of V-0 when measured by a method conforming to UL94 for test specimens having a thickness of 1.5 mm or less, and more preferably V-0 when measured for specimens having a thickness of 0.8 mm or less. Here, UL94 is a standard established by Underwriter Laboratories Inc. in the United States. This makes it possible for molded articles made from polyamide resin compositions to be used in products that require flame retardancy and include thin-walled sections for the purpose of weight reduction. Examples of methods for achieving V-0 flame retardancy for test specimens having a thickness of 1.5 mm or less include increasing the amount of flame retardants such as magnesium hydroxide or phosphazene and inorganic fibrous fillers as non-combustible components, and reducing the amount of polyamide resin as a combustible component.

[0073] The molded article of the present invention preferably has a tracking resistance of 600 V or more as measured by a method in accordance with IEC 60112 (2003). By setting the tracking resistance within the above range, the molded article can withstand higher voltages, which makes it possible to shorten the creepage distance and contributes to the miniaturization of the final product. One method for setting the tracking resistance within the above range is, for example, to increase the blending amount of a polyamide resin that has excellent tracking resistance.

[0074] The polyamide resin composition of the present invention has excellent thermal conductivity, fluidity, and flame retardancy without significantly impairing the excellent mechanical strength and tracking resistance that are inherent to polyamide resins, and therefore can be used in molded products including thin-walled portions and metal insert molded products, particularly electrical and electronic components and automotive and vehicle-related components.

[0075] Other applications of the polyamide resin composition of the present invention include, for example, electrical components for electric vehicles, such as batteries, motors, power control units, and peripheral components of sensors; various pipes, hoses, and tubes for fuel, cooling, brake, wiper, exhaust, and intake systems; air intake nozzle snorkels; intake manifolds; fuel pumps; fuel tanks; 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; air flow meters; brake pad wear sensors; battery peripheral components; thermostat bases for air conditioners; heater hot air flow control valves; brush holders for radiator motors; water pump impellers; turbine vanes; wiper motor-related components; distributors; starter switches; starter relays; transmission wire harnesses; transmission oil pans; transmission oil filters; Windshield washer nozzles, air conditioning panel switch boards, fuel-related electromagnetic valve coils, wire harness connectors, SMJ connectors, printed circuit board connectors, door grommet connectors, various connectors such as fuse connectors, horn terminals, electrical component insulating plates, step motor rotors, lamp sockets, lamp reflectors, lamp housings, brake pistons, solenoid bobbins, engine oil pans, engine oil filters, ignition device cases, torque control levers, safety belt parts, register blades, washer levers, window regulator handles, window regulator handle knobs, passing light levers, sun visor brackets, instrument panels, airbag peripheral parts, door pads, pillars, console boxes, various motor housings, roof rails, fenders, garnishes, roof panels, hood panels, trunk lids, door mirror stays, spoilers, hood louvers, wheel covers, wheel caps, grill apron cover frames, lamp bezels, door handles, door moldings, rear finishers,Electrical components related to automobiles and vehicles such as wipers, connectors, relay cases, relay bases, relay spools, switches, coils, sensors, various gears, LED lamps, sockets, resistors, 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, semiconductors, liquid crystal displays, floppy disk drive carriages, floppy disk drive chassis, motor brush holders, parabolic antennas, thermal protectors, electronic components such as computer-related parts, generators, electric motors, transformers, current transformers, voltage regulators, rectifiers, inverters, relays, power contacts, switches, circuit breakers, knife switches, other-pole rods, electrical equipment parts such as electrical component cabinets, VTR parts, television parts, irons, hair dryers, rice cooker parts, microwave oven parts, audio parts, audio and laser devices It can be used in audio equipment such as discs (registered trademark) and compact discs, lighting parts, refrigerator parts, air conditioner parts, typewriter parts, word processor parts, personal computer parts, personal computer cases, mobile phone parts, mobile phone cases, smartphone parts, smartphone cases, battery parts, battery cases, and other household and office electrical appliance parts, office computer related parts, telephone related parts, facsimile related parts, copier related parts, cleaning jigs, various bearings such as oil-less bearings, stern bearings, and underwater bearings, machine-related electrical parts such as motor parts, lighters, and typewriters, optical equipment and precision machinery-related electrical parts such as microscope parts, binoculars, camera parts, and watch parts, alternator terminals, alternator connectors, IC regulators, potentiometer bases for light dimmers, and electrical parts surrounding various valves such as exhaust gas valves, and is particularly useful for connectors, relays, switches, personal computer cases, mobile phone cases, and battery cases. [Example]

[0076] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to the following examples. Characterization was carried out according to the following methods.

[0077] [Method for evaluating polyamide resins produced in reference examples] (1) Melting point Approximately 5 mg of sample was collected and measured under a nitrogen atmosphere using a robot DSC-RDC220 (Seiko Instruments Inc.) under the following conditions: After heating to the melting point + 40°C to create a molten state, the sample was cooled to 30°C at a rate of 20°C / min, held at 30°C for 3 minutes, and then heated to the melting point + 40°C at a rate of 20°C / min, and the temperature of the endothermic peak (melting point: Tm) observed was determined.

[0078] (2) Tensile strength The resin composition pellets obtained in each example and comparative example were vacuum dried at 80°C and then used in an "EC75" injection molding machine (Shibaura Machine Co., Ltd.) to injection-mold Type A1 test specimens as specified in ISO 20753 (2008) under the following conditions: cylinder temperature: 280°C, mold temperature: 80°C, injection speed: 23 mm / sec, holding pressure: 50 MPa, and cooling time: 15 seconds. Tensile strength was measured using the resulting molded specimens at a gauge length of 64 mm and a pulling speed of 5 mm / min according to ISO 527-1 and -2. Five test specimens were measured for each sample, and the number average was calculated.

[0079] (3) Impact strength Charpy impact test specimens (notched) measuring 80 mm in length, 10 mm in width, and 4 mm in thickness were cut from the parallel section of the Type A1 test specimens specified in ISO 20753 (2008) obtained under the above molding conditions. Using these Charpy impact test specimens, the Charpy impact strength (notched) was measured according to ISO 179. Measurements were conducted on seven test specimens for each material, and the number average value was calculated.

[0080] (4) Thermal conductivity The resin composition pellets obtained in each example and comparative example were vacuum dried at 80°C and injection molded into rectangular plates (80mm x 80mm x 3mm thick, film gate) using an "EC75" injection molding machine (Shibaura Machine Co., Ltd.) under conditions of a cylinder temperature of 280°C, a mold temperature of 80°C, and a lower limit pressure (minimum filling pressure) of +10MPa. Using these molded products, thermal conductivity was measured by the hot disc method in accordance with ISO 22007-2 using a "TPS-2500S" (Kyoto Electronics Manufacturing Co., Ltd.). Each measurement was performed three times, and the number average value was calculated.

[0081] (5) Flame retardancy Flame retardancy was evaluated based on flammability measured using the following method in accordance with UL94. Specifically, resin composition pellets obtained in each example and comparative example were vacuum-dried at 80°C and then injection-molded into rectangular molded products (13 mm × 125 mm × 0.8 mm thick, film gate, and 13 mm × 125 mm × 1.5 mm thick, pin gate) using a cylinder temperature of 280°C, a mold temperature of 80°C, and a lower limit pressure (minimum filling pressure) of +10 MPa. These molded products were evaluated for flame retardancy according to the evaluation criteria specified in the UL94 vertical test. Flame retardancy is ranked in descending order of V-0 > V-1 > V-2. Materials with poor flame retardancy that did not meet the V-2 rating were classified as non-standard (V-out).

[0082] (6) Tracking resistance The resin composition pellets obtained in each example and comparative example were vacuum dried at 80°C and then injection molded into a rectangular plate (80mm x 80mm x 3mm thick, film gate) using an "EC75" injection molding machine (Shibaura Machine Co., Ltd.) under conditions of a cylinder temperature of 280°C, a mold temperature of 80°C, and a lower limit pressure (minimum filling pressure) of +10MPa. Using these molded products, the maximum voltage at which tracking failure did not occur was measured in accordance with IEC 60112 (2003). A 0.1% aqueous ammonium chloride solution was used as the electrolyte. The higher this maximum voltage, the better the tracking resistance, with 600V being preferred.

[0083] (7) Extrusion processability The raw materials of each example and comparative example were fed into a twin-screw extruder through a raw material supply port upstream and melt-kneaded, and the extruded strands were pelletized to obtain pelletized resin compositions. If continuous production for 30 minutes or more was possible and strand breakage occurred less than once every 5 minutes, the process was rated as A; if raw material supply stopped between 10 and 30 minutes or strand breakage occurred once every 1 to 5 minutes or more, the process was rated as B; and if raw material supply stopped within 10 minutes or strand breakage occurred once every 1 minute or more, the process was rated as C.

[0084] (8) Liquidity The resin composition pellets obtained in each example and comparative example were vacuum dried at 80°C and used in an "EC75" injection molding machine (manufactured by Shibaura Machine Co., Ltd.) to mold them under the following conditions: cylinder temperature: 280°C, mold temperature: 80°C, injection pressure: 100 MPa, injection speed: 100 mm / min. The flow length of molded articles with a width of 10 mm and a thickness of 1 mm was measured. Measurements were made 10 times for each case, and the number average value was calculated. The longer this flow length, the better the moldability.

[0085] (9) Heat cycle resistance Using the resin compositions obtained in each example and comparative example, a metal insert molded product was obtained by overmolding the resin composition to a thickness of 1.5 mm onto a metal block (S45C) using an injection molding machine SE50-DUZ manufactured by Sumitomo Heavy Industries, Ltd., under conditions of a cylinder temperature of 280°C and a mold temperature of 80°C. The obtained metal insert molded product was subjected to thermal shock treatment using a TSA-73ES-W (manufactured by Espec Corporation), with one treatment at 130°C for one hour and then at -40°C for one hour. The presence or absence of cracks was visually confirmed every two treatments. The number of thermal shock treatments at which cracks were observed was defined as heat cycle resistance. The more treatments required until cracks appeared, the better the heat cycle resistance (thermal shock resistance) and the more preferable it was.

[0086] The (A) polyamide resin, (B) magnesium hydroxide, (B') inorganic filler other than component (B), (C) inorganic fibrous filler, (D) phosphazene compound, and (D') flame retardant other than component (D) used in the present examples and comparative examples are as follows:

[0087] (A) Polyamide resin (A-1): Polyamide 66 / 6I / 6 (=76 / 17 / 7 parts by weight) resin having a melting point of 228°C and a viscosity of 85 ml / g measured in accordance with ISO 307 (A-2): Polyamide 6 resin having a melting point of 225°C and a viscosity number of 108 ml / g measured in accordance with ISO 307 (A-3): Polyamide 66 resin having a melting point of 263°C and a viscosity number of 117 ml / g measured in accordance with ISO 307 (A-4): Polyamide 610 resin having a melting point of 225°C and a viscosity number of 112 ml / g measured in accordance with ISO 307 (A-5): Polyamide 66 / 6I (=70 / 30 parts by weight) resin having a melting point of 220°C and a viscosity number of 85 ml / g measured in accordance with ISO307.

[0088] (B) Magnesium hydroxide (B-1): Magnesium hydroxide "KISUMA" (registered trademark) 5EU (Kyowa Chemical Industry Co., Ltd.) having an average primary particle size of 0.7 μm and a loose bulk density of 0.6 g / mL (B-2): Magnesium hydroxide "Junmag" (registered trademark) 4S (manufactured by Fimatec Corporation) with an average primary particle size of 4.0 μm and a loose bulk density of 0.6 g / mL (B-3): Magnesium hydroxide "Sample A" with an average primary particle size of 15.0 μm and a loose bulk density of 0.6 g / mL (B-4): Magnesium hydroxide "Sample B" with an average primary particle size of 0.05 μm and a loose bulk density of 0.6 g / mL (B-5): Magnesium hydroxide "KISUMA" (registered trademark) 5P (manufactured by Kyowa Chemical Industry Co., Ltd.) having an average primary particle size of 0.7 μm and a loose bulk density of 0.2 g / mL. (B') Inorganic fillers that do not fall under the category of component (B) (B'-1): Magnesium carbonate "Magthermo" (registered trademark) MS-PS (manufactured by Konoshima Chemical Co., Ltd.) having an average primary particle size of 21.0 μm and a loose bulk density of 1.16 g / mL.

[0089] (C) Inorganic fibrous filler (C-1): Chopped strand "ECS10-03-568H" (manufactured by Megaishi JAPAN Co., Ltd.) (C-2): Chopped strand "T-275H" (manufactured by Nippon Electric Glass Co., Ltd.).

[0090] (D) Phosphazene Compounds (D-1): "HPCTP" (manufactured by HighChem Co., Ltd.).

[0091] (D') Flame retardants that do not fall under the category of component (D) (D'-1): "OP1312" (Clariant Japan Co., Ltd.) (D'-2): "MC25" (Italmatch) (D'-3): "PATOX-MK" (manufactured by Nihon Seiko Co., Ltd.) (D'-4): "SAYTEX" (registered trademark) HP-7010G" (manufactured by Albemarle Japan Co., Ltd.).

[0092] (Examples 1 to 15, Comparative Examples 1 to 7) The raw materials were fed into the raw material supply port upstream of the twin-screw extruder using the blending compositions shown in Tables 1, 2, and 3, and melt-kneaded. The extruded strands were pelletized to obtain a pellet-shaped resin composition. The twin-screw extruder used was a TEX44αII manufactured by The Japan Steel Works, Ltd., and melt-kneading was carried out at a cylinder temperature of the polyamide resin melting point + 15°C, a screw rotation speed of 185 rpm, and a discharge rate of 160 kg / hr. The evaluation results for each example and comparative example are shown in Tables 1 to 3.

[0093] [Table 1]

[0094] [Table 2]

[0095] [Table 3]

[0096] From Examples 1 to 15 shown in Tables 1 and 2, it can be seen that by containing specific amounts of (B) magnesium hydroxide, (C) inorganic fibrous filler, and (D) phosphazene compound, the tensile strength, impact strength, thermal conductivity, flame retardancy, tracking resistance, fluidity, and heat cycle resistance are excellent.

[0097] In Example 2 shown in Table 1, the type of inorganic fibrous filler (C) was changed from that in Example 1. It was found that regardless of the type of inorganic fibrous filler (C), the tensile strength, impact strength, thermal conductivity, flame retardancy, tracking resistance, fluidity, and heat cycle resistance were excellent.

[0098] In Examples 3 to 6 shown in Table 1, the content of the (D) phosphazene compound was changed from that of Example 1. As the content of the (D) phosphazene compound was reduced, the tensile strength improved, but the impact strength, flame retardancy, and fluidity decreased. It can be seen that as the content of the (D) phosphazene compound was increased, the impact strength and fluidity improved, but the tensile strength decreased.

[0099] In Example 7 shown in Table 1 and Example 8 shown in Table 2, the average primary particle size of (B) magnesium hydroxide was changed from that of Example 1. It can be seen that increasing the average primary particle size improves the thermal conductivity and fluidity, but decreases the tensile strength and impact strength.

[0100] In Example 9 shown in Table 2, the average primary particle size of (B) magnesium hydroxide was changed from that of Example 1. It can be seen that reducing the average primary particle size improves the tensile strength and impact strength, but reduces the thermal conductivity, extrusion processability, and fluidity. In terms of extrusion processability, strand breakage frequently occurred.

[0101] In Example 10 shown in Table 2, the loose bulk density of (B) magnesium hydroxide was changed from that of Example 1. It can be seen that reducing the loose bulk density reduces the extrusion processability. In terms of extrusion processability, the transportability of the raw material decreased.

[0102] In Examples 11 to 15 shown in Table 2, the type of polyamide resin (A) was changed from that in Example 1. It can be seen that when polyamide 6 resin, polyamide 66 resin, and polyamide 610 resin were used, the tensile strength, impact strength, and fluidity were reduced. In particular, when polyamide 66 resin and polyamide 610 resin were used, the fluidity of the resin during extrusion was reduced, resulting in an increase in torque. It can be seen that when polyamide 66 / 6I resin was used, the tensile strength, impact strength, and fluidity were reduced.

[0103] Comparative Example 1 shown in Table 3 was obtained by removing the phosphazene compound (D) from Example 1. Since the phosphazene compound (D) was not used, the flame retardancy was poor, the torque during extrusion increased, the extrusion processability was poor, and the flowability was also poor. Furthermore, the heat cycle resistance was insufficient.

[0104] In Comparative Example 2 shown in Table 3, the phosphazene compound (D) was removed from Example 1, and the magnesium hydroxide (B) content was increased. It was found that the composition exhibited excellent flame retardancy at 1.5 mm, but insufficient flame retardancy at 0.8 mm, and was also inferior in tensile strength, impact strength, extrusion processability, and fluidity. Furthermore, the heat cycle resistance was significantly poor.

[0105] In Comparative Example 3 shown in Table 3, magnesium carbonate was used instead of magnesium hydroxide (B) in Example 1. It can be seen that the flame retardancy and heat cycle resistance were poor.

[0106] In Comparative Example 4 shown in Table 3, (B) magnesium hydroxide and (C) inorganic fibrous filler were reduced and (D) phosphazene compound was increased compared to Example 1. It was found that the tensile strength, impact strength, thermal conductivity, extrusion processability, and heat cycle resistance were inferior.

[0107] In Comparative Examples 5 to 7 shown in Table 3, a flame retardant other than component (D) was used instead of the phosphazene compound (D) in Example 1. It was found that the use of a flame retardant other than a phosphazene compound resulted in inferior tensile strength, impact strength, flame retardancy, extrusion processability, and heat cycle resistance. [Industrial Applicability]

[0108] The resin composition of the present invention has excellent flame retardancy, thermal conductivity, and flowability without significantly impairing the excellent mechanical strength and tracking resistance inherent to polyamide resins, making it suitable for molded products, including thin-walled parts, that require heat dissipation and flame retardancy, such as automotive parts and electrical / electronic parts. Furthermore, since it has excellent heat cycle resistance in addition to the above properties, it can be suitably used in metal insert molding.

Claims

1. A polyamide resin composition comprising 100 parts by weight of (A) polyamide resin, 60 to 170 parts by weight of (B) magnesium hydroxide, 60 to 170 parts by weight of (C) inorganic fibrous filler, and 5 to 35 parts by weight of (D) a phosphazene compound.

2. 2. The polyamide resin composition according to claim 1, wherein the amount of the phosphazene compound (D) blended is 10 to 25 parts by weight.

3. 3. The polyamide resin composition according to claim 1, wherein the average primary particle size of the magnesium hydroxide (B) is from 0.1 μm to 10 μm.

4. 3. The polyamide resin composition according to claim 1, wherein the magnesium hydroxide (B) has a loose bulk density of 0.3 g / mL or more.

5. 3. The polyamide resin composition according to claim 1, wherein the polyamide resin (A) comprises a polyamide 66 / 6I / 6 copolymer and / or a 66 / 6I copolymer.

6. 3. The polyamide resin composition according to claim 1, wherein the polyamide resin (A) is a polyamide 66 / 6I / 6 copolymer.

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

8. The molded product according to claim 7, wherein the molded product has a thermal conductivity of 0.8 W / (m K) or more as measured by a hot disk method in accordance with ISO 22007-2.

9. The molded article according to claim 7, wherein the flammability of the molded article measured by a method conforming to UL94 is V-0 for a test piece having a thickness of 1.5 mm or less.

10. The molded article according to claim 7, wherein the molded article has a tracking resistance of 600 V or more as measured by a method in accordance with IEC 60112 (2003).

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