Polyamide resin composition and molded article

Abstract

To provide a polyamide resin composition capable of achieving both high flame retardancy and impact resistance at low temperature.SOLUTION: The polyamide resin composition contains a polyamide resin (A), a modified ethylene / α - olefin copolymer (B) modified with an unsaturated carboxylic acid or a derivative thereof, a phosphinate (C), a nitrogen-containing (poly) phosphate (D), and an inorganic filler (E).SELECTED DRAWING: None

Description

[Technical Field]

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

[0002] Polyamide resins have excellent mechanical properties, heat resistance, chemical resistance, etc., and therefore compositions containing polyamide resins are widely used as molding materials for various parts such as automobile parts, electric or electronic parts, building materials, etc. In particular, polyamide resin compositions used for automobile parts (e.g., bus bars, etc.) and electric or electronic parts are desirably imparted with flame retardancy.

[0003] A known method for imparting flame retardancy to a polyamide resin composition is to incorporate a flame retardant. While halogen-based flame retardants have traditionally been used primarily as flame retardants, non-halogen flame retardants that do not contain halogen elements have recently begun to be used. For example, Patent Document 1 discloses a resin composition containing a specific semi-aromatic polyamide, polyphenylene ether, a phosphinate as a flame retardant, and an inorganic filler.

[0004] Furthermore, polyamide resin compositions used in automobile parts and electric / electronic parts are also required to have improved impact resistance, particularly heat shock resistance, at low temperatures.

[0005] One known method for imparting impact resistance to a polyamide resin composition is to incorporate a modifier such as an olefinic elastomer or a styrene elastomer. For example, Patent Document 2 discloses a polyamide resin composition containing a polyamide resin (A), an olefinic elastomer (B), a nitrogen-based flame retardant (C), and a phosphorus-based flame retardant (D). The olefinic elastomer (B) is an acid-modified ethylene-butene copolymer or an acid-modified ethylene-propylene copolymer. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Application Laid-Open No. 2008-38149 [Patent Document 2] Japanese Patent Application Laid-Open No. 2013-189512 Summary of the Invention [Problem to be solved by the invention]

[0007] However, according to the investigations of the present inventors, when a polyamide resin composition containing a flame retardant further contains, for example, an olefin copolymer as a modifier, the flame retardancy is likely to be significantly reduced compared to when other modifiers are contained or when no olefin copolymer is contained. In particular, it has been found that when a non-halogen flame retardant is used, the flame retardancy is more likely to be reduced than when a halogen-based flame retardant is used.

[0008] An object of the present invention is to provide a polyamide resin composition and a molded article thereof that can achieve both high flame retardancy and impact resistance at low temperatures. [Means for solving the problem]

[0009] The present invention relates to the following polyamide resin composition and molded article.

[0010] [1] A polyamide resin composition comprising a polyamide resin (A), a modified ethylene-α-olefin copolymer (B) modified with an unsaturated carboxylic acid or a derivative thereof, a phosphinate (C), a nitrogen-containing (poly)phosphate (D), and an inorganic filler (E). [2] The polyamide resin composition according to [1], wherein the mass ratio of the content of the nitrogen-containing (poly)phosphate (D) to the content of the phosphinate (C) is 0.05 or more and 0.5 or less. [3] The polyamide resin composition according to [1] or [2], wherein the total content of the phosphinate (C) and the nitrogen-containing (poly)phosphate (D) is 10% by mass or more and 30% by mass or less, based on the total mass of the polyamide resin composition. [4] The polyamide resin composition according to any one of [1] to [3], wherein the mass ratio of the content of the nitrogen-containing (poly)phosphate (D) to the content of the modified ethylene-α-olefin copolymer (B) is 0.3 or more and 1.5 or less. [5] The polyamide resin composition according to any one of [1] to [4], wherein the content of the modified ethylene-α-olefin copolymer (B) is 1.00 mass% or more and 10.00 mass% or less, based on the total mass of the polyamide resin composition. [6] The polyamide resin composition according to any one of [1] to [5], wherein the polyamide resin (A) comprises a polyamide resin (A-1) having a melting point of 280°C or higher as measured by a differential scanning calorimeter (DSC). [7] The polyamide resin composition according to [6], wherein the polyamide resin (A-1) comprises a structural unit (A-1a) derived from a dicarboxylic acid and a structural unit (A-1b) derived from a diamine, the structural unit (A-1a) derived from the dicarboxylic acid comprises a structural unit derived from terephthalic acid, and the structural unit (A-1b) derived from the diamine comprises a structural unit derived from 1,6-diaminohexane. [8] The polyamide resin composition according to [6] or [7], wherein the polyamide resin (A) further contains a polyamide resin (A-2) that has substantially no melting point. [9] The polyamide resin composition according to any one of [1] to [8], wherein the content of the inorganic filler (E) is 10% by mass or more and 50% by mass or less based on the total mass of the polyamide resin composition.

[10] A molded article obtained by molding the polyamide resin composition according to any one of [1] to [9]. [Effects of the Invention]

[0011] According to the present invention, it is possible to provide a polyamide resin composition and a molded article thereof that can achieve both high flame retardancy and impact resistance at low temperatures. [Brief explanation of the drawings]

[0012] [Figure 1] FIG. 1A is a perspective view showing the shape of an insert test piece prepared to evaluate heat shock resistance in the examples, FIG. 1B is a plan view of the insert test piece, and FIG. 1C is a cross-sectional view of the insert test piece taken along line A-A' shown in FIG. 1B. DETAILED DESCRIPTION OF THE INVENTION

[0013] As described above, the inventors' investigations have revealed that polyamide resin compositions containing an olefin copolymer as a modifier are particularly prone to a decrease in flame retardancy. In response to this, the inventors investigated various flame retardants and found that by combining a metal phosphinate with a nitrogen-containing (poly)phosphate, the decrease in flame retardancy can be effectively suppressed even when the olefin-based copolymer described above is contained, thereby achieving a high level of both impact resistance and flame retardancy at low temperatures.

[0014] The reason for this is not clear, but is presumed to be as follows. When a polyamide resin composition contains a phosphoric acid compound such as a phosphinate (C) or a nitrogen-containing (poly)phosphate (D), a char (carbonized film) is formed on the surface of a molded article formed from the polyamide resin composition upon combustion. Because char has a thermal insulating effect, the formation of char on the surface of the molded article inhibits the gasification of the components in the polyamide resin composition and, even if the components in the polyamide resin composition are gasified, inhibits the release of the gas outside the molded article. This results in suppression of fire spread and improved flame retardancy. The higher the phosphorus content of the phosphoric acid compound, the denser the char formed. Therefore, to effectively block gas, it is preferable to use a phosphoric acid compound with a high phosphorus content, such as a phosphinate (C). Furthermore, when a nitrogen-containing (poly)phosphate (D) is used as the phosphoric acid compound, the char formed is foamed char, resulting in a char with high thermal insulating properties.

[0015] On the other hand, when the polyamide resin composition contains a modified ethylene-α-olefin copolymer (B), the modified ethylene-α-olefin copolymer (B) is very susceptible to gasification, so that a char formed only from the phosphinate (C) has insufficient heat insulating effect, and gasification of the modified ethylene-α-olefin copolymer (B) proceeds rapidly upon combustion of the molded article, making it difficult to exhibit sufficient flame retardancy. Also, a char formed only from the nitrogen-containing (poly)phosphate (D) is not dense enough, making its gas barrier effect insufficient, making it difficult to exhibit sufficient flame retardancy.

[0016] In contrast, it is believed that by using a combination of a phosphinate (C) and a nitrogen-containing (poly)phosphate (D), the denseness of the char formed by the phosphinate (C) can be increased, while the nitrogen-containing (poly)phosphate (D) can foam the char, thereby enhancing the heat insulating effect. As a result, it is believed that the polyamide resin composition can exhibit sufficient flame retardancy even when it contains a modified ethylene-α-olefin copolymer (B).

[0017] Hereinafter, embodiments of the present invention will be described in detail, but the present invention is not limited to the following embodiments.

[0018] 1. Polyamide resin composition The polyamide resin composition according to this embodiment contains a polyamide resin (A), a modified ethylene-α-olefin copolymer (B), a phosphinate (C), a nitrogen-containing (poly)phosphate (D), and an inorganic filler (E).

[0019] 1-1. Polyamide resin (A) In one embodiment, the polyamide resin (A) comprises a polyamide resin (A-1) having a melting point of 280° C. or higher, and may further comprise a polyamide resin (A-2) having substantially no melting point, as needed.

[0020] These polyamide resins are preferably semi-aromatic polyamide resins containing aromatic rings in the skeleton. The content of aromatic ring-containing structural units in these polyamide resins is preferably, for example, 20 mol% to 70 mol%, more preferably 30 mol% to 60 mol%, based on the total number of moles of diamine-derived structural units and dicarboxylic acid-derived structural units. The content of aromatic ring-containing structural units can be measured by the NMR method described below.

[0021] 1-1-1. Polyamide resin (A-1) The melting point of the polyamide resin (A-1) measured by a differential scanning calorimeter (DSC) is preferably 280°C or higher. The polyamide resin (A-1) not only has high heat resistance but also high crystallinity, and therefore can further increase the mechanical strength (tensile strength, etc.) of the molded article. The method for measuring the melting point of the polyamide resin (A-1) will be described later.

[0022] The polyamide resin (A-1) contains, for example, a structural unit (A-1a) derived from a dicarboxylic acid and a structural unit (A-1b) derived from a diamine.

[0023] (Structural unit (A-1a) derived from dicarboxylic acid) The dicarboxylic acid-derived structural unit (A-1a) preferably contains a structural unit derived from an aromatic dicarboxylic acid, more preferably a structural unit derived from terephthalic acid. By containing a structural unit derived from an aromatic dicarboxylic acid, preferably terephthalic acid, the melting point (Tm) and crystallinity of the polyamide resin (A-1) can be further increased.

[0024] The content of the structural units derived from terephthalic acid is preferably 20 mol% to 100 mol%, more preferably 30 mol% to 90 mol%, even more preferably 40 mol% to 85 mol%, and even more preferably 40 mol% to 65 mol%, based on the total number of moles of the structural units (A-1a) derived from dicarboxylic acids. When the content of the structural units derived from terephthalic acid is 20 mol% or more, the crystallinity of the polyamide resin (A-1) is further increased, thereby enabling the heat resistance and mechanical strength of the molded article to be further improved. Furthermore, when the content of the structural units derived from terephthalic acid is 20 mol% or more, the aromatic ring concentration in the polyamide resin (A) is increased, making the polyamide resin more susceptible to carbonization. This allows the flame retardancy of the molded article to be further improved.

[0025] The dicarboxylic acid-derived structural unit (A-1a) may contain a structural unit derived from another dicarboxylic acid. Examples of the other dicarboxylic acid include aliphatic dicarboxylic acids, alicyclic dicarboxylic acids, and aromatic dicarboxylic acids other than terephthalic acid. Of these, aliphatic dicarboxylic acids and aromatic dicarboxylic acids other than terephthalic acid are preferred.

[0026] Examples of aliphatic dicarboxylic acids include aliphatic dicarboxylic acids having 4 to 20 carbon atoms. The number of carbon atoms is preferably 6 to 12. Examples of such aliphatic dicarboxylic acids include adipic acid, azelaic acid, and sebacic acid. Among these, adipic acid and sebacic acid are preferred, and adipic acid is more preferred.

[0027] The content of the structural units derived from aliphatic dicarboxylic acids is preferably 0 mol% or more and 80 mol% or less, more preferably 10 mol% or more and 70 mol% or less, even more preferably 15 mol% or more and 60 mol% or less, and still more preferably 35 mol% or more and 60 mol% or less, relative to the total number of moles of the structural units (A-1a) derived from dicarboxylic acids.

[0028] Examples of alicyclic dicarboxylic acids include cyclohexanedicarboxylic acid and its esters. Examples of aromatic dicarboxylic acids other than terephthalic acid include isophthalic acid, 2-methylterephthalic acid, and naphthalenedicarboxylic acid.

[0029] The content of structural units derived from alicyclic dicarboxylic acids and aromatic dicarboxylic acids other than terephthalic acid is preferably from 0 mol % to 80 mol % and may be from 0 mol % to 60 mol % relative to the total number of moles of structural units (A-1a) derived from dicarboxylic acids.

[0030] The dicarboxylic acid-derived structural units (A-1a) preferably contain 40 mol% to 85 mol% of structural units derived from terephthalic acid and 15 mol% to 60 mol% of structural units derived from an aliphatic dicarboxylic acid having 4 to 20 carbon atoms, relative to the total number of moles of structural units derived from the dicarboxylic acid-derived structural units (A-1a). More preferably, the dicarboxylic acid-derived structural units (A-1a) contain 40 mol% to 65 mol% of structural units derived from terephthalic acid and 35 mol% to 60 mol% of structural units derived from an aliphatic dicarboxylic acid having 4 to 20 carbon atoms. By containing 40 mol% or more of structural units derived from terephthalic acid, the heat resistance and mechanical strength of the molded article can be further improved. By containing 15 mol% or more of structural units derived from an aliphatic dicarboxylic acid, the melting point (Tm) of the polyamide resin (A-1) can be appropriately lowered, thereby further improving moldability.

[0031] (Structural unit (A-1b) derived from diamine) The diamine-derived structural unit (A-1b) preferably includes an aliphatic diamine-derived structural unit.

[0032] The carbon number of the aliphatic diamine is preferably 4 to 15, more preferably 4 to 12, and even more preferably 6 to 12. Examples of the aliphatic diamine include linear alkylenediamines and branched alkylenediamines.

[0033] Examples of linear alkylenediamines include 1,4-diaminobutane, 1,6-diaminohexane, 1,7-diaminoheptane, 1,8-diaminooctane, 1,9-diaminononane, 1,10-diaminodecane, 1,11-diaminoundecane, and 1,12-diaminododecane. Among these, 1,6-diaminohexane, 1,9-nonanediamine, and 1,10-diaminodecane are preferred, and 1,6-diaminohexane is more preferred. Only one type of linear alkylenediamine may be included, or two or more types may be included.

[0034] Examples of branched alkylenediamines include 2,2-dimethyldiaminopropane, 1,1-dimethyl-1,4-diaminobutane, 1-ethyl-1,4-diaminobutane, 1,2-dimethyl-1,4-diaminobutane, 1,3-dimethyl-1,4-diaminobutane, 1,4-dimethyl-1,4-diaminobutane, 2,3-dimethyl-1,4-diaminobutane, 2-methyl-1,5-diaminopentane, 2,5-dimethyl-1,6-diaminohexane, 2,4-diamino Methyl-1,6-diaminohexane, 3,3-dimethyl-1,6-diaminohexane, 2,2-dimethyl-1,6-diaminohexane, 2,2,4-trimethyl-1,6-diaminohexane, 2,4,4-trimethyl-1,6-diaminohexane, 2,4-diethyl-1,6-diaminohexane, 2,3-dimethyl-1,7-diaminoheptane, 2,4-dimethyl-1,7-diaminoheptane, 2,5-dimethyl-1,7-diaminoheptane, 2,2-di Methyl-1,7-diaminoheptane, 2-methyl-4-ethyl-1,7-diaminoheptane, 2-ethyl-4-methyl-1,7-diaminoheptane, 2,2,5,5-tetramethyl-1,7-diaminoheptane, 3-isopropyl-1,7-diaminoheptane, 3-isooctyl-1,7-diaminoheptane, 2-methyl-1,8-diaminooctane, 1,3-dimethyl-1,8-diaminooctane, 1,4-dimethyl-1,8-diaminooctane, 2, Examples of suitable diaminooctane include 4-dimethyl-1,8-diaminooctane, 3,4-dimethyl-1,8-diaminooctane, 4,5-dimethyl-1,8-diaminooctane, 2,2-dimethyl-1,8-diaminooctane, 3,3-dimethyl-1,8-diaminooctane, 4,4-dimethyl-1,8-diaminooctane, 3,3,5-trimethyl-1,8-diaminooctane, 2,4-diethyl-1,8-diaminooctane, and 5-methyl-1,9-diaminononane. Among these, 2-methyl-1,5-diaminopentane and 2-methyl-1,8-diaminooctane are preferred, and 2-methyl-1,5-diaminopentane is more preferred.

[0035] The content of the structural units derived from aliphatic diamine is preferably 30 mol % or more and 100 mol % or less, and more preferably 70 mol % or more and 100 mol % or less, relative to the total number of moles of the structural units (A-1b) derived from diamine.

[0036] The diamine-derived structural unit (A-1b) may contain a structural unit derived from another diamine. Examples of the other diamine include alicyclic diamines and aromatic diamines having from 4 to 20 carbon atoms.

[0037] Examples of the alicyclic diamine having 4 to 20 carbon atoms include 1,4-diaminocyclohexane, 1,3-diaminocyclohexane, 1,3-bis(aminomethyl)cyclohexane, 2,5-bisaminomethylnorbornane, and 2,6-bisaminomethylnorbornane. Examples of the aromatic diamine include metaxylylenediamine.

[0038] The content of the structural units derived from alicyclic diamines and aromatic diamines is preferably 0 mol% or more and 70 mol% or less, and more preferably 0 mol% or more and 30 mol% or less, relative to the total number of moles of the structural units (Ab) derived from diamines.

[0039] The respective structural units of the polyamide resin (A-1) and their ratios can be calculated from the charge ratios when the polyamide resin (A-1) is prepared, or can be measured by the NMR method.

[0040] 1 In the case of H-NMR measurement, for example, a nuclear magnetic resonance apparatus (ECX400 model manufactured by JEOL Ltd.) is used, the solvent is deuterated orthodichlorobenzene, the sample concentration is 20 mg / 0.6 mL, the measurement temperature is 120 °C, and the observation nucleus is 1The conditions are H (400 MHz), sequence is single pulse, pulse width is 5.12 μsec (45° pulse), repetition time is 7.0 sec, and the number of accumulations is 500 or more. The reference chemical shift is set to 0 ppm for hydrogen in tetramethylsilane, but similar results can also be obtained by setting the peak derived from residual hydrogen in deuterated orthodichlorobenzene at 7.10 ppm as the reference value for the chemical shift. 1 Peaks such as H can be assigned by conventional methods.

[0041] 13 In the case of C-NMR measurement, for example, a nuclear magnetic resonance spectrometer (ECP500 model manufactured by JEOL Ltd.) is used as the measurement device, a mixed solvent of ortho-dichlorobenzene / heavy benzene (80 / 20% by volume) is used as the solvent, the measurement temperature is 120°C, and the observation nucleus is 13 The conditions were: C (125 MHz), single pulse proton decoupling, 45° pulse, repetition time 5.5 seconds, accumulation number 10,000 or more, and chemical shift reference value 27.50 ppm. Assignment of various signals was performed based on the standard method, and quantification could be performed based on the accumulated value of signal intensity.

[0042] In the polyamide resin (A-1), the dicarboxylic acid-derived structural unit (A-1a) preferably contains a structural unit derived from terephthalic acid, and the diamine-derived structural unit (A-1b) preferably contains a structural unit derived from 1,6-diaminohexane.

[0043] Specific examples of the polyamide resin (A-1) include polyamide 6T6I, polyamide 6T66, polyamide 6TDT, etc. Of these, polyamide 6T66 is preferred. That is, the polyamide resin (A-1) preferably contains, as the dicarboxylic acid-derived structural units (A-1a), structural units derived from terephthalic acid and structural units derived from adipic acid, and as the diamine-derived structural units (A-1b), structural units derived from 1,6-diaminohexane. The polyamide resin (A-1) may contain only one type of polyamide resin, or may contain two or more types of polyamide resins. In this specification, polyamide resins containing the same type of structural units but different amounts of the structural units are treated as two or more types of polyamide resins.

[0044] The molecular ends of the polyamide resin (A-1) may be capped with a terminal capping agent.

[0045] Examples of end-capping agents include monocarboxylic acids and monoamines. Examples of monocarboxylic acids include aliphatic monocarboxylic acids having 2 to 30 carbon atoms, such as acetic acid, propionic acid, butyric acid, valeric acid, caproic acid, and caprylic acid; alicyclic monocarboxylic acids, such as cyclohexanecarboxylic acid; and aromatic monocarboxylic acids, such as benzoic acid, toluic acid, naphthalenecarboxylic acid, methylnaphthalenecarboxylic acid, and phenylacetic acid. Examples of monoamines include aliphatic monoamines, such as butylamine, amylamine, and hexylamine; and aromatic aliphatic monoamines, such as benzylamine and methylbenzylamine.

[0046] (Physical Properties) From the viewpoint of further increasing the mechanical strength of the molded article, the melting point of the polyamide resin (A-1) is preferably 280° C. or higher, more preferably 290° C. or higher, and even more preferably 300° C. or higher. Furthermore, from the viewpoint of suppressing decomposition of the amide bond of the polyamide resin (A-1), the melting point of the polyamide resin (A-1) is preferably 330° C. or lower.

[0047] The melting point of the polyamide resin (A-1) can be adjusted to fall within the above range by adjusting the composition. For example, the melting point can be increased by increasing the content of structural units derived from terephthalic acid.

[0048] The polyamide resin (A-1) preferably has a glass transition temperature (Tg) measured by differential scanning calorimetry (DSC) of 70°C or higher and 145°C or lower, more preferably 75°C or higher and 125°C or lower, and even more preferably 80°C or higher and 100°C or lower. A glass transition temperature (Tg) of 70°C or higher increases the temperature at which molecular mobility becomes active in high-temperature environments, thereby suppressing molecular mobility and further improving the heat resistance of the polyamide resin composition and molded articles. A glass transition temperature (Tg) of 145°C or lower makes it easier to maintain the fluidity of the resin composition without excessively increasing the mold temperature during molding, thereby improving molding processability.

[0049] The heat of fusion (ΔH) of the polyamide resin (A-1) measured by differential scanning calorimetry (DSC) is preferably greater than 5 J / g. The heat of fusion is an index of the crystallinity of a resin, with a larger heat of fusion indicating higher crystallinity. When the heat of fusion (ΔH) of the polyamide resin (A-1) exceeds 5 J / g, the crystallinity is increased, and the mechanical strength of the resulting molded article can be further increased. Furthermore, from the viewpoint of further increasing the crystallinity of the polyamide resin (A-1) and further increasing the mechanical strength of the molded article, the heat of fusion (ΔH) is preferably 30 J / g or more, and more preferably 40 J / g or more. The upper limit of the heat of fusion (ΔH) is not particularly limited, but is, for example, 100 J / g.

[0050] The melting point and heat of fusion (ΔH) of the polyamide resin (A-1) can be measured using a differential scanning calorimeter (DSC220C model, manufactured by Seiko Instruments Inc.). Specifically, approximately 5 mg of polyamide resin (A) is sealed in a measuring aluminum pan and heated from room temperature to 350°C at 10°C / min. To completely melt the resin, it is held at 350°C for 3 minutes and then cooled to 30°C at 10°C / min. After leaving it at 30°C for 5 minutes, it is heated a second time to 350°C at 10°C / min. The temperature (°C) of the endothermic peak during this second heating is taken as the melting point (Tm) of polyamide resin (A-1), and the inflection point corresponding to the glass transition is taken as the glass transition temperature (Tg). The heat of fusion (ΔH) is determined from the area of ​​the endothermic peak during melting during the first heating process in accordance with JIS K7122.

[0051] The polyamide resin (A-1) preferably has an intrinsic viscosity [η] of 0.7 dL / g or more and 1.2 dL / g or less, more preferably 0.7 dL / g or more and 1.0 dL / g or less, as measured in 96.5% sulfuric acid at 25°C. When the polyamide resin (A-1) has an intrinsic viscosity [η] of 0.7 dL / g or more, the mechanical strength of the molded article can be further increased. When the intrinsic viscosity [η] is 1.2 dL / g or less, the decrease in fluidity during molding can be further suppressed.

[0052] The intrinsic viscosity [η] can be adjusted by adjusting the molar ratio of the dicarboxylic acid-derived structural unit (A-1a) and the diamine-derived structural unit (A-1b). Specifically, the closer the molar ratio of the dicarboxylic acid-derived structural unit (A-1a) and the diamine-derived structural unit (A-1b) is to 1:1, the higher the intrinsic viscosity can be. It can also be adjusted by the amount of end-capping of the polyamide resin (A-1).

[0053] The intrinsic viscosity [η] of polyamide resin (A-1) can be measured as follows. 0.5 g of polyamide resin (A-1) is dissolved in 50 ml of 96.5% sulfuric acid solution to prepare a sample solution. The flow time of the obtained solution at 25°C ± 0.05°C is measured using an Ubbelohde viscometer, and the intrinsic viscosity [η] is calculated according to the following formula: [η]=ηSP / (C*(1+0.205ηSP)) [η]: Intrinsic viscosity (dl / g) ηSP: Specific viscosity C: Sample concentration (g / dl) t: Number of seconds for sample solution to flow down (seconds) t0: Number of seconds the blank sulfuric acid flows (seconds) ηSP=(t-t0) / t0

[0054] The polyamide resin (A-1) can be produced by the same method as that for known polyamide resins, for example, by polycondensing a dicarboxylic acid and a diamine in a homogeneous solution. Specifically, as described in WO 03 / 085029, the polyamide resin (A-1) can be produced by heating a dicarboxylic acid and a diamine in the presence of a catalyst to obtain a low-order condensate, and then applying shear stress to a melt of the low-order condensate to polycondense it.

[0055] 1-1-2. Polyamide resin (A-2) The polyamide resin (A) may further contain a polyamide resin (A-2) having a molecular structure different from that of the polyamide resin (A-1). In this way, a polyamide resin composition containing two or more polyamide resins having different molecular structures tends to have a moderately low crystallinity of the polyamide resin (A). As a result, the resulting molded article can have a more moderate flexibility while maintaining high heat resistance and mechanical strength.

[0056] The polyamide resin (A-2) is preferably amorphous or has lower crystallinity than the polyamide resin (A-1). Specifically, the polyamide resin (A-2) preferably has substantially no melting point.

[0057] As used herein, "having substantially no melting point" means that, in the measurement of the melting point using a differential scanning calorimeter (DSC), substantially no endothermic peak due to crystalline melting is observed during the second heating (from room temperature to 330°C). "Substantially no endothermic peak is observed" means that the heat of fusion (ΔH) of polyamide resin (A-2) measured by differential scanning calorimetry (DSC) is 0 J / g or more and 5 J / g or less. The heat of fusion can be measured by the same method as described for polyamide resin (A-1).

[0058] As mentioned above, the polyamide resin (A-2) preferably has a small heat of fusion, specifically, 0 J / g.

[0059] The heat of fusion (ΔH) of the polyamide resin (A-2) can be adjusted to fall within the above range by adjusting the composition of the polyamide resin. For example, the heat of fusion can be reduced by increasing the content of structural units derived from isophthalic acid, which will be described later.

[0060] The polyamide resin (A-2) contains a structural unit (A-2a) derived from a dicarboxylic acid and a structural unit (A-2b) derived from a diamine.

[0061] (Structural unit (A-2a) derived from dicarboxylic acid) The dicarboxylic acid-derived structural unit (A-2a) preferably contains a structural unit derived from an aromatic dicarboxylic acid, and more preferably contains a structural unit derived from isophthalic acid. By containing a structural unit derived from isophthalic acid, the crystallinity of the polyamide resin (A-2) can be further reduced.

[0062] The content of structural units derived from isophthalic acid is preferably more than 50 mol% and not more than 100 mol%, more preferably 55 mol% to 95 mol%, and even more preferably 60 mol% to 80 mol%, based on the total number of moles (A-2a) of components derived from dicarboxylic acids in the polyamide resin (A-2). When the content of isophthalic acid structural units is more than 50 mol%, the crystallinity of the polyamide resin (A-2) can be appropriately reduced, and the impact resistance of the resulting molded article can be further improved.

[0063] The dicarboxylic acid-derived structural unit (A-2a) may further contain a structural unit derived from another dicarboxylic acid other than the structural unit derived from isophthalic acid, as long as the effects of the present invention are not impaired. Examples of the other dicarboxylic acid include aromatic dicarboxylic acids other than isophthalic acid, aliphatic dicarboxylic acids, and alicyclic dicarboxylic acids. Among these, aromatic dicarboxylic acids other than isophthalic acid are preferred, and terephthalic acid is more preferred.

[0064] The content of the structural units derived from other dicarboxylic acids can be, for example, from 0 mol% to 50 mol% inclusive, preferably from 5 mol% to 45 mol% inclusive, and more preferably from 20 mol% to 40 mol% inclusive, relative to the total number of moles of the structural units (b1) derived from dicarboxylic acids.

[0065] (Structural unit (A-2b) derived from diamine) The diamine-derived structural unit (A-2b) is the same as the diamine-derived structural unit (A-1b) of the polyamide resin (A-1).

[0066] (others) Examples of the polyamide resin (A-2) include polyamide 6I and polyamide 6I6T.

[0067] The polyamide resin (A-2) preferably has an intrinsic viscosity [η] measured in concentrated sulfuric acid at 25°C of 0.4 dl / g or more and 1.60 dl / g or less, more preferably 0.5 dl / g or more and 1.20 dl / g or less.

[0068] The polyamide resin (A-2) preferably has a glass transition temperature (Tg) measured by a differential scanning calorimeter (DSC) of 80°C or higher and 150°C or lower, and more preferably 90°C or higher and 140°C or lower. When the glass transition temperature (Tg) is 80°C or higher, the heat resistance of the polyamide resin composition and molded article can be further improved. When the glass transition temperature (Tg) is 150°C or lower, the moldability can be further improved.

[0069] When polyamide resin (A) contains polyamide resin (A-2), the content of polyamide resin (A-2) is preferably 10% by mass or more and 30% by mass or less, and more preferably 15% by mass or more and 25% by mass or less, based on the total content of polyamide resin (A-1) and polyamide resin (A-2). A content of 10% by mass or more prevents the crystallinity of the polyamide resin from becoming too high, thereby enabling the impact resistance of the molded article to be further improved. Furthermore, a content of 10% by mass or more allows the impact resistance of the molded article to be improved even when the amount of modified ethylene-α-olefin copolymer (B) added is reduced, resulting in further improved flame retardancy.

[0070] 1-1-3. Polyamide resin (A-3) In another embodiment, the polyamide resin (A) may include a polyamide resin (A-3) having a melting point lower than 280°C.

[0071] The melting point of the polyamide resin (A-3) is preferably 220° C. or higher and 280° C. or lower. The melting point can be measured by the same method as described above. Such polyamide resin (A-3) is not particularly limited as long as it has a melting point within the above range, but is preferably an aliphatic polyamide resin.

[0072] In the aliphatic polyamide resin, the content of structural units derived from aliphatic compounds not containing aromatic rings (such as aliphatic dicarboxylic acids and aliphatic diamines, aminocarboxylic acids, and lactams described below) is preferably more than 80 mol%, more preferably 90 mol% or more, and even more preferably 95 mol% or more, and may be 100 mol%, based on the total number of moles of structural units constituting the aliphatic polyamide resin.

[0073] The polyamide (A-3) may be a product obtained by polycondensation of an aliphatic dicarboxylic acid and an aliphatic diamine, a product obtained by polycondensation of an aminocarboxylic acid, or a product obtained by ring-opening polymerization of a lactam. That is, the polyamide (A-3) preferably satisfies at least one of the following conditions (1) and (2): (1) The polymer contains a structural unit (A-3a) derived from an aliphatic dicarboxylic acid and a structural unit (A-3b) derived from an aliphatic diamine. (2) It contains at least one structural unit (A-3c) selected from the group consisting of structural units derived from lactams and structural units derived from aminocarboxylic acids.

[0074] (Structural Unit (A-3a) Derived from Aliphatic Dicarboxylic Acid) The structural unit (A-3a) derived from an aliphatic dicarboxylic acid preferably contains a structural unit derived from an aliphatic dicarboxylic acid having from 4 to 20 carbon atoms, preferably from 6 to 12 carbon atoms. Examples of such aliphatic dicarboxylic acids include oxalic acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, dodecanedioic acid, and tetradecanedioic acid. Of these, adipic acid, azelaic acid, and sebacic acid are preferred, and adipic acid is more preferred.

[0075] (Structural Unit (A-3b) Derived from Aliphatic Diamine) The structural unit (A-3b) derived from an aliphatic diamine may be the same as the aliphatic diamine in the structural unit (A-1b) derived from the diamine described above.

[0076] (At least one structural unit (A-3c) selected from the group consisting of structural units derived from lactams and structural units derived from aminocarboxylic acids) The structural unit derived from an aminocarboxylic acid may be a structural unit derived from an aminocarboxylic acid having from 6 to 12 carbon atoms, preferably from 6 to 10 carbon atoms. Examples of such aminocarboxylic acids include 6-aminocaproic acid, 7-aminoheptanoic acid, 11-aminoundecanoic acid, 12-aminododecanoic acid, etc.

[0077] The lactam-derived structural unit may be a structural unit derived from a lactam having from 6 to 12 carbon atoms, preferably from 6 to 10 carbon atoms. Examples of such lactams include α-pyrrolidone, ε-caprolactam, undecanelactam, ω-laurolactam, ε-enantholactam, and the like.

[0078] Examples of the polyamide resin (A-3) include polyamide 6, polyamide 66, polyamide 610, polyamide 612, polyamide 92, and polyamide 1010, with polyamide 6, polyamide 66, and polyamide 610 being preferred.

[0079] (Physical Properties) The heat of fusion (ΔH) of the polyamide resin (A-3) measured by differential scanning calorimetry (DSC) is preferably greater than 5 J / g, more preferably 15 J / g or more, and even more preferably 20 J / g or more. When the heat of fusion (ΔH) of the polyamide resin (A-3) exceeds 5 J / g, the crystallinity is increased, and the mechanical strength of the resulting molded article can be further increased. The upper limit of the heat of fusion (ΔH) is not particularly limited, but is, for example, 100 J / g.

[0080] The intrinsic viscosity [η] of the polyamide resin (A-3) may be the same as the intrinsic viscosity [η] of the polyamide resin (A-1).

[0081] 1-1-4.Common matters The content of polyamide resin (A) is not particularly limited, but is preferably 25.0 to 55.0 mass% based on the total mass of the polyamide resin composition, for example, preferably 30.0 to 45.0 mass%, and more preferably 33.0 to 45.0 mass%. A content of 33.0 mass% or more can further increase the mechanical strength (e.g., tensile strength) of the molded article. A content of 55.0 mass% or less can further increase the content of the modified ethylene-α-olefin copolymer (B), phosphinate (C), nitrogen-containing (poly)phosphate (D), and the like, which will be described later, and therefore can further improve impact resistance and flame retardancy at low temperatures.

[0082] The dicarboxylic acid-derived structural units contained in the polyamide resins (A-1), (A-2), and (A-3) may include structural units derived from biomass-derived dicarboxylic acids, and the diamine-derived structural units may include structural units derived from biomass-derived diamines. Furthermore, the polyamide resins (A-1), (A-2), and (A-3) may be biomass-derived polyamide resins obtained by polymerizing raw materials including biomass-derived raw materials.

[0083] 1-2. Modified ethylene-α-olefin copolymer (B) The modified ethylene-α-olefin copolymer (B) is an ethylene-α-olefin copolymer modified with an unsaturated carboxylic acid or its derivative. In other words, the modified ethylene-α-olefin copolymer (B) has a structure derived from an unsaturated carboxylic acid or its derivative in its molecular structure. The structural units derived from the unsaturated carboxylic acid or its derivative in the modified ethylene-α-olefin copolymer (B) interact with the amino and carboxyl groups at the molecular terminals of the polyamide resin (A), thereby achieving good compatibility with the polyamide resin (A) and imparting impact resistance to the polyamide resin composition. The modified ethylene-α-olefin copolymer (B) can be obtained by reacting an ethylene-α-olefin copolymer with an unsaturated carboxylic acid or its derivative.

[0084] Ethylene-α-olefin copolymers are polymers containing structural units derived from ethylene and structural units derived from α-olefins other than ethylene.

[0085] The α-olefin other than ethylene may be, for example, an α-olefin having a carbon number of 3 or more and 20 or less, preferably 3 or more and 10 or less. Examples of the α-olefin other than ethylene include propylene, 1-butene, 1-pentene, 1-hexene, 4-methyl-1-pentene, 1-octene, 1-decene, etc. Among these, propylene, 1-butene, 1-hexene, 4-methyl-1-pentene, and 1-octene are preferred.

[0086] The content of structural units derived from α-olefins other than ethylene is preferably 0.5 mol% or more and 30 mol% or less, and more preferably 1 mol% or more and 20 mol% or less, relative to the total content of structural units derived from ethylene and structural units derived from α-olefins.

[0087] Examples of unsaturated carboxylic acids include acrylic acid, methacrylic acid, maleic acid, fumaric acid, itaconic acid, and phthalic acid. Examples of derivatives of unsaturated carboxylic acids include dicarboxylic acid anhydrides having an α,β-unsaturated bond, such as maleic anhydride, itaconic anhydride, and phthalic anhydride. Of these, maleic anhydride is preferred. This enhances the affinity between the polyamide resin (A) and the modified ethylene-α-olefin copolymer (B), making the modified ethylene-α-olefin copolymer (B) more easily dispersible in the polyamide resin composition.

[0088] The content (modification amount) of structural units derived from unsaturated carboxylic acid or derivatives thereof in the modified ethylene-α-olefin copolymer (B) is not particularly limited, but is preferably from 0.1 to 5.0 mass%, more preferably from 0.2 to 3.0 mass%, and even more preferably from 0.5 to 1.5 mass%. When the content of structural units derived from unsaturated carboxylic acid or derivatives thereof is within the above range, the impact resistance and elongation of the resin composition are likely to be further improved.

[0089] The content of structural units derived from unsaturated carboxylic acid or its derivatives in the modified ethylene-α-olefin copolymer (B) can be calculated from the charge ratio during preparation of the modified ethylene-α-olefin copolymer (B) or measured by NMR. The NMR method can be the same as that described for the polyamide resin (A).

[0090] The modified ethylene-α-olefin copolymer (B) preferably has an MFR (according to ASTM D1238 at 230°C under a load of 2.16 kg) of, for example, 0.5 g / 10 min or more and 20 g / 10 min or less. When the MFR is 0.5 g / 10 min or more, the melt fluidity of the polyamide resin composition at high temperatures is less likely to be impaired, and when the MFR is 20 g / 10 min or less, gas generation during kneading can be further suppressed.

[0091] The reaction of an ethylene-α-olefin copolymer with an unsaturated carboxylic acid or its derivative, that is, the modification method, is, for example, a graft modification method.

[0092] Graft modification can be carried out by various conventionally known methods. For example, it may be carried out by a melt modification method in which an unmodified ethylene-α-olefin copolymer is melted using an extruder and a graft monomer is added to carry out graft copolymerization, or it may be carried out by a solution modification method in which an unmodified ethylene-α-olefin copolymer is dissolved in a solvent and a graft monomer is added to carry out graft copolymerization. In either case, it is preferable to carry out the reaction in the presence of a radical initiator in order to efficiently graft copolymerize the graft monomer.

[0093] The content of the modified ethylene-α-olefin copolymer (B) is not particularly limited, but is preferably 1.00% by mass or more and 10.00% by mass or less, and more preferably 1.50% by mass or more and 5.00% by mass or less, relative to the total mass of the polyamide resin composition. A content of 1.00% by mass or more can further increase the impact resistance of the molded article at low temperatures, thereby further increasing the heat shock resistance. A content of 10.00% by mass or less can further suppress a decrease in flame retardancy.

[0094] 1-3. Phosphinate (C) The phosphinate (C), together with the nitrogen-containing polyphosphate (D) described below, can impart flame retardancy to the polyamide resin composition. The phosphinate (C) is preferably a metal phosphinate. Examples of the metal phosphinate (C) include compounds represented by formula (I) or formula (II).

[0095] [ka]

[0096] In formula (I) and formula (II), R 1 and R 2 are each independently a linear or branched alkyl group or an aryl group having 1 to 6 carbon atoms. R 3 is a linear or branched alkylene group having 1 to 10 carbon atoms, an arylene group having 6 to 10 carbon atoms, an alkylarylene group having 6 to 10 carbon atoms, or an arylalkylene group having 6 to 10 carbon atoms. M is Mg, Ca, Al, Sb, Sn, Ge, Ti, Zn, Fe, Zr, Ce, Bi, Sr, Mn, Li, Na, or K. m, n, and x each independently represent an integer of 1 to 4.

[0097] Specific examples of the phosphinate (C) include calcium dimethylphosphinate, magnesium dimethylphosphinate, aluminum dimethylphosphinate, zinc dimethylphosphinate, calcium ethylmethylphosphinate, magnesium ethylmethylphosphinate, aluminum ethylmethylphosphinate, zinc ethylmethylphosphinate, calcium diethylphosphinate, magnesium diethylphosphinate, aluminum diethylphosphinate, zinc diethylphosphinate, calcium methyl-n-propylphosphinate, magnesium methyl-n-propylphosphinate, aluminum methyl-n-propylphosphinate, zinc methyl-n-propylphosphinate, and calcium methanedi(methylphosphinate). Methane di(methylphosphinate), magnesium methane di(methylphosphinate), aluminum methane di(methylphosphinate), zinc methane di(methylphosphinate), calcium benzene-1,4-(dimethylphosphinate), magnesium benzene-1,4-(dimethylphosphinate), aluminum benzene-1,4-(dimethylphosphinate), zinc benzene-1,4-(dimethylphosphinate), calcium methylphenylphosphinate, magnesium methylphenylphosphinate, aluminum methylphenylphosphinate, zinc methylphenylphosphinate, calcium diphenylphosphinate, magnesium diphenylphosphinate, aluminum diphenylphosphinate, zinc diphenylphosphinate, etc. Among these, calcium dimethylphosphinate, aluminum dimethylphosphinate, zinc dimethylphosphinate, calcium ethylmethylphosphinate, aluminum ethylmethylphosphinate, zinc ethylmethylphosphinate, calcium diethylphosphinate, aluminum diethylphosphinate, and zinc diethylphosphinate are preferred, with aluminum diethylphosphinate being more preferred.

[0098] The phosphorus content of the phosphinate (C) is preferably 20% by mass or more and 30% by mass or less, and more preferably 20% by mass or more and 25% by mass or less, based on the total mass of the phosphinate (C). A phosphorus content of 20% by mass or more can not only further enhance the flame retardancy of the polyamide resin composition but also further enhance tracking resistance. That is, phosphoric acid is more likely to be produced from the phosphinate (C) by heat generated by application of voltage to the molded product, thereby more likely to hydrolyze the polyamide resin (A). Because the hydrolysis reaction is an endothermic reaction, heating of the polyamide resin (A) by heat generated by application of voltage to the molded product is suppressed, thereby improving tracking resistance. Furthermore, a content of 30% by mass or less can suppress excessive generation of phosphoric acid during melt-kneading, further suppressing decomposition of the polyamide resin (A), and further suppressing a resulting decrease in the impact resistance of the molded product at low temperatures. Furthermore, by setting the content to 30% by mass or less, the content of the polyamide resin (A) relative to the entire polyamide resin composition can be increased, thereby further suppressing the decrease in toughness. The phosphorus content can be measured, for example, by high-frequency inductively coupled plasma (ICP) emission spectrometry.

[0099] The median diameter (D50) of the phosphinic acid salt (C) is not particularly limited, but is preferably 5 μm or more and 100 μm or less, more preferably 10 μm or more and 80 μm or less, even more preferably 20 μm or more and 60 μm or less, and particularly preferably 25 μm or more and 45 μm or less. When the median diameter of the phosphinic acid salt (C) is 5 μm or more, the specific surface area of ​​the phosphinic acid salt (C) can be appropriately reduced, thereby further improving dispersibility. When the median diameter of the phosphinic acid salt (C) is 100 μm or less, the specific surface area of ​​the phosphinic acid salt (C) can be appropriately increased, thereby making it easier to further improve flame retardancy. The median diameter (D50) of the phosphinic acid salt (C) can be measured by dynamic light scattering.

[0100] The content of the phosphinate (C) is not particularly limited, but is preferably 5% by mass or more and 30% by mass or less, based on the total mass of the polyamide resin composition. When the content is 5% by mass or more, the tracking resistance of the molded article can be further improved, while the flame retardancy can be further improved. When the content is 30% by mass or less, the impact resistance of the molded article at low temperatures can be further maintained.

[0101] In particular, when the polyamide resin (A) contains the polyamide resin (A-1) and, if necessary, the polyamide resin (A-2), the content of the phosphinate (C) is preferably from 5 to 20% by mass, more preferably from 7.5 to 17.5% by mass, and particularly preferably from 9 to 15% by mass, relative to the total mass of the polyamide resin composition. On the other hand, when the polyamide resin (A) contains the polyamide resin (A-3), the content of the phosphinate (C) is more preferably 10% by mass or more and 30% by mass or less, further preferably 15% by mass or more and 27.5% by mass or less, and particularly preferably 20% by mass or more and 26% by mass or less, relative to the total mass of the polyamide resin composition.

[0102] 1-4. Nitrogen-containing (poly)phosphates (D) The nitrogen-containing (poly)phosphate (D) may be an adduct of a nitrogen-containing compound and (poly)phosphoric acid. Examples of the nitrogen-containing compound include melamine-based compounds (melamine, melam, etc.), piperazine, and ammonium, with melamine-based compounds being preferred, and melamine being more preferred. Examples of the (poly)phosphoric acid include orthophosphoric acid and polyphosphoric acid (including pyrophosphoric acid), with polyphosphoric acid being preferred.

[0103] From the viewpoint of further improving heat resistance and flame retardancy, the nitrogen-containing (poly)phosphate (D) preferably contains an adduct of melamine and (poly)phosphoric acid, and more preferably contains melamine polyphosphate, which is represented by the formula (C3H6N6·HPO3)n (n is the degree of condensation).

[0104] The degree of condensation n of melamine polyphosphate is not particularly limited, but can be, for example, from 2 to 50, and preferably from 3 to 50. In particular, from the viewpoint of further improving heat resistance and flame retardancy, it is more preferably from 5 to 50.

[0105] The median diameter (D50) of the nitrogen-containing (poly)phosphate (D) is not particularly limited, but is preferably 1 μm or more and 20 μm or less, more preferably 1 μm or more and 10 μm or less, and even more preferably 1 μm or more and 6 μm or less. When the median diameter is within the above range, the nitrogen-containing (poly)phosphate (D) can be well dispersed while exhibiting higher flame retardancy. The median diameter of the nitrogen-containing (poly)phosphate (D) can be measured in the same manner as the median diameter of the phosphinate (C).

[0106] The content of the nitrogen-containing (poly)phosphate (D) is preferably 0.5% by mass or more and 10% by mass or less, more preferably 0.75% by mass or more and 7.5% by mass or less, even more preferably 1% by mass or more and 5% by mass or less, and particularly preferably 2% by mass or more and 5% by mass or less, relative to the total mass of the polyamide resin composition. When the content is 0.5% by mass or more, the flame retardancy of the molded article can be further improved. When the content is 10% by mass or less, gas generation during molding is more easily suppressed, and the impact resistance of the molded article at low temperatures is less likely to be impaired.

[0107] From a similar viewpoint, the mass ratio of the content of the nitrogen-containing (poly)phosphate (D) to the content of the modified ethylene-α-olefin copolymer (B) is preferably, for example, 0.3 or more and 1.5 or less, and more preferably 0.5 or more and 1.2 or less.

[0108] Furthermore, the mass ratio of the content of the nitrogen-containing (poly)phosphate (D) to the content of the phosphinate (C) is preferably 0.05 or more and 0.5 or less. When the mass ratio is 0.05 or more, the flame retardancy of the molded article can be further improved. When the mass ratio is 0.5 or less, gas generation during molding can be more easily suppressed, and deterioration of moldability due to mold contamination can be more easily suppressed. In particular, when the polyamide resin (A) contains a polyamide resin (A-1) and, if necessary, a polyamide resin (A-2), the mass ratio of the content of the nitrogen-containing (poly)phosphate (D) to the content of the phosphinate (C) is more preferably 0.05 or more and 0.4 or less, even more preferably 0.06 or more and 0.4 or less, and particularly preferably more than 0.25 and 0.35 or less. On the other hand, when the polyamide resin (A) contains the polyamide resin (A-3), the mass ratio of the content of the nitrogen-containing (poly)phosphate (D) to the content of the phosphinate (C) is more preferably 0.05 or more and 0.3 or less, and even more preferably 0.05 or more and 0.2 or less.

[0109] The total content of the phosphinate (C) and the nitrogen-containing (poly)phosphate (D) is not particularly limited, but is preferably 10% by mass or more and 30% by mass or less relative to the total mass of the polyamide resin composition. When the total content is 10% by mass or more, the flame retardancy of the molded article can be further improved. When the total content is 30% by mass or less, the impact resistance of the molded article at low temperatures is less likely to be impaired.

[0110] In particular, when the polyamide resin (A) contains a polyamide resin (A-1) and, if necessary, a polyamide resin (A-2), the total content of the phosphinate (C) and the nitrogen-containing (poly)phosphate (D) is preferably 10% by mass or more and 20% by mass or less, and more preferably 12% by mass or more and 17% by mass or less, based on the total mass of the polyamide resin composition. In this case, it is particularly preferable that the total content of the phosphinate (C) and the nitrogen-containing (poly)phosphate (D) is 10% by mass or more and 20% by mass or less, based on the total mass of the polyamide resin composition, and that the mass ratio of the content of the nitrogen-containing (poly)phosphate (D) to the content of the phosphinate (C) is 0.05 to 0.4. This allows for a better balance between high flame retardancy and low-temperature impact resistance. On the other hand, when the polyamide resin (A) contains a polyamide resin (A-3), the total content of the phosphinate (C) and the nitrogen-containing (poly)phosphate (D) is more preferably 20% by mass or more and 30% by mass or less, and even more preferably 25% by mass or more and 30% by mass or less, relative to the total mass of the polyamide resin composition. In this case, it is particularly preferable that the total content of the phosphinate (C) and the nitrogen-containing (poly)phosphate (D) is 20% by mass or more and 30% by mass or less, relative to the total mass of the polyamide resin composition, and that the mass ratio of the content of the nitrogen-containing (poly)phosphate (D) to the content of the phosphinate (C) is 0.05 to 0.2. This allows for a better balance between high flame retardancy and low-temperature impact resistance.

[0111] 1-5. Inorganic filler (E) The type of inorganic filler (E) is not particularly limited, and may be a fibrous reinforcing material or a granular reinforcing material, of which fibrous reinforcing materials are preferred from the viewpoint of easily increasing the mechanical strength of the molded body.

[0112] Examples of fibrous reinforcing materials include glass fiber, wollastonite, potassium titanate whiskers, calcium carbonate whiskers, aluminum borate whiskers, magnesium sulfate whiskers, zinc oxide whiskers, milled fiber, cut fiber, etc. Among these, wollastonite, glass fiber, and potassium titanate whiskers are preferred, and wollastonite and glass fiber are more preferred.

[0113] The average fiber length of the fibrous reinforcing material is preferably 1 μm or more and 20 mm or less, more preferably 5 μm or more and 10 mm or less, from the viewpoints of moldability of the polyamide resin composition and the mechanical strength and heat resistance of the resulting resin part.

[0114] The cross-sectional shape of the fibrous reinforcing material may be circular or non-circular, but is preferably circular from the viewpoint of increasing the tensile strength of the molded article. When the molded article has a thick portion, the fibers tend to be oriented in the thickness direction of the thick portion, so a circular shape can exert a stronger reinforcing effect (the effect of increasing the tensile strength of the molded article) against cracks that occur inside the thick portion. The above cross-sectional shape can be confirmed by observation with an optical microscope.

[0115] The average fiber length and average fiber diameter of the fibrous reinforcing material can be measured by the following method. 1) The polyamide resin composition is dissolved in a hexafluoroisopropanol / chloroform solution (0.1 / 0.9% by volume), and then filtered to obtain a filtrate. 2) Disperse the filtered material obtained in 1) above in water, and measure the fiber length (Li) and fiber diameter (di) of each of 300 randomly selected fibers using an optical microscope (magnification: 50x). The number of fibers with fiber length Li is taken as qi, and the weight-average length (Lw) is calculated using the following formula, which is the average fiber length of the fibrous reinforcement. Weight average length (Lw) = (Σqi × Li 2 ) / (Σqi×Li) Similarly, the number of fibers with a fiber diameter Di is taken as ri, and the weight average diameter (Dw) is calculated based on the following formula, and this is taken as the average fiber diameter of the fibrous reinforcing material. Weight average diameter (Dw)=(Σri×Di 2 ) / (Σri×Di)

[0116] The content of the inorganic filler (E) is preferably 10.0 mass% or more and 50.0 mass% or less, and more preferably 25.0 mass% or more and 40.0 mass% or less, based on the total mass of the polyamide resin composition. When the content of the inorganic filler (E) is 10.0 mass% or more, the mechanical strength of the molded article can be further increased. When the content of the inorganic filler (E) is 50.0 mass% or less, not only is moldability further improved, but the shear force during melt-kneading does not become too large, so decomposition of the phosphinate (C), the nitrogen-containing (poly)phosphate (D), etc. can be further suppressed.

[0117] 1-6.Other ingredients The polyamide resin composition may contain other known components.

[0118] Examples of other components include flame retardant synergists, nucleating agents, lubricants, anti-drip agents, halogen scavengers, colorants, heat stabilizers (lactone compounds, vitamin E's, hydroquinones, etc.), corrosion resistance improvers, anti-drip agents, ion scavengers, elastomers (rubbers), antistatic agents, mold release agents, antioxidants (phenols, amines, sulfurs, phosphorus compounds, etc.), and light stabilizers (benzotriazoles, triazines, benzophenones, benzoates, hindered amines, oxanilides, etc.).

[0119] (Flame retardant synergist) The flame retardant synergist is not particularly limited as long as it can enhance the flame retardancy provided by the above-mentioned phosphinate (C) and nitrogen-containing (poly)phosphate (D). Examples of the flame retardant synergist include anhydrous sodium antimonate, hydrotalcite, boehmite, zinc stannate, iron oxide, zinc oxide, tin oxide, zinc borate compounds, etc.

[0120] The content of the flame retardant aid is, for example, preferably 0.5% by mass or more and 5.0% by mass or less, and more preferably 1.0% by mass or more and 3.0% by mass or less, relative to the total mass of the polyamide resin composition.

[0121] (nucleating agent) The nucleating agent can promote the crystallization of the polyamide resin (A) and thereby increase the mechanical strength of the molded article.

[0122] Examples of nucleating agents include metal salt compounds such as sodium 2,2-methylenebis(4,6-di-t-butylphenyl)phosphate, aluminum tris(pt-butylbenzoate), and stearates, sorbitol compounds such as bis(p-methylbenzylidene)sorbitol and bis(4-ethylbenzylidene)sorbitol, and inorganic substances such as talc, calcium carbonate, and hydrotalcite. Of these, talc is preferred from the viewpoint of further increasing the crystallinity of the molded body.

[0123] Talc generally contains hydrous magnesium silicate (SiO2: 58-64%, MgO: 28-32%, Al2O3: 0.5-5%, Fe2O3: 0.3-5%) as its main component. The average particle size of the talc is preferably, for example, 1-15 μm, more preferably 1-7.5 μm. When the average particle size of the talc is within the above range, the talc can be easily dispersed in the polyamide resin (A) without impairing the fluidity of the polyamide resin composition. The average particle size of the talc can be measured by a laser diffraction method, for example, using a Shimadzu particle size distribution analyzer (SALD-2000A) manufactured by Shimadzu Corporation.

[0124] The content of the nucleating agent is, for example, preferably 0.10% by mass or more and 5.00% by mass or less, and more preferably 0.10% by mass or more and 3.00% by mass or less, relative to the total mass of the polyamide resin composition.

[0125] (lubricant) The lubricant improves the injection flowability of the polyamide resin composition and improves the appearance of the resulting molded article. The lubricant can be a metal salt of a fatty acid such as a metal salt of an oxycarboxylic acid or a metal salt of a higher fatty acid.

[0126] The oxycarboxylic acid in the oxycarboxylic acid metal salt may be an aliphatic oxycarboxylic acid or an aromatic oxycarboxylic acid. Examples of aliphatic oxycarboxylic acids include aliphatic oxycarboxylic acids having 10 to 30 carbon atoms, such as α-hydroxymyristic acid, α-hydroxypalmitic acid, α-hydroxystearic acid, α-hydroxyeicosanoic acid, α-hydroxydocosanoic acid, α-hydroxytetraeicosanoic acid, α-hydroxyhexaeicosanoic acid, α-hydroxyoctaeicosanoic acid, α-hydroxytriacontanoic acid, β-hydroxymyristic acid, 10-hydroxydecanoic acid, 15-hydroxypentadecanoic acid, 16-hydroxyhexadecanoic acid, 12-hydroxystearic acid, and ricinoleic acid. Examples of aromatic oxycarboxylic acids include salicylic acid, m-hydroxybenzoic acid, p-hydroxybenzoic acid, gallic acid, mandelic acid, and trovic acid.

[0127] Examples of the metal in the metal oxycarboxylic acid salt include alkali metals such as lithium, and alkaline earth metals such as magnesium, calcium, and barium.

[0128] Of these, the metal oxycarboxylic acid salt is preferably a metal salt of 12-hydroxystearic acid, and more preferably magnesium 12-hydroxystearate, calcium 12-hydroxystearate, and barium 12-hydroxystearate.

[0129] Examples of the higher fatty acid in the higher fatty acid metal salt include higher fatty acids having 15 to 30 carbon atoms, such as stearic acid, oleic acid, behenic acid, behenic acid, and montanic acid.

[0130] Examples of metals in the higher fatty acid metal salts include calcium, magnesium, barium, lithium, aluminum, zinc, sodium, and potassium.

[0131] Of these, preferred higher fatty acid metal salts are calcium stearate, magnesium stearate, barium stearate, calcium behenate, sodium montanate, and calcium montanate.

[0132] The content of the lubricant is preferably 0.01% by mass or more and 1.30% by mass or less based on the total mass of the polyamide resin composition.

[0133] (coloring agent) The type of colorant is not particularly limited, but may be, for example, a pigment.

[0134] For example, black pigments include carbon black (e.g., acetylene black, lamp black, thermal black, furnace black, channel black, and Ketjen black), white pigments include titanium oxide and zinc oxide, yellow pigments include azo-based organic pigments, lead yellow, chrome yellow, and zinc yellow, red pigments include iron oxide red, orange pigments include molybdate orange, blue pigments include ultramarine blue and cobalt blue, and green pigments include chromium oxide and cobalt green.

[0135] The content of the colorant is not particularly limited, but is preferably, for example, 0.02% by mass or more and 1% by mass or less relative to the total mass of the polyamide resin composition.

[0136] 1-7. Method for producing polyamide resin composition The polyamide resin composition can be produced by a known resin kneading method, for example, by mixing the above-mentioned polyamide resin (A), modified ethylene-α-olefin copolymer (B), phosphinate (C), nitrogen-containing (poly)phosphate (D), inorganic filler (E), and, if necessary, other components, using a Henschel mixer, V-blender, ribbon blender, or tumbler blender, or by mixing and then melt-kneading the mixture using a single-screw extruder, multi-screw extruder, kneader, or Banbury mixer, followed by granulation or pulverization.

[0137] 2. Uses of polyamide resin compositions The polyamide resin composition can be used as a molded article by molding it using a known molding method such as compression molding, injection molding, or extrusion molding.

[0138] Molded articles of the polyamide resin composition can be used for various applications, including electrical and electronic components such as automotive electrical components, connectors, switches, jacks, plugs, breakers, electromagnetic switches, current interrupters, and LED reflective materials, as well as various molded articles for automotive components. [Example]

[0139] The present invention will be described below with reference to examples, which should not be construed as limiting the scope of the present invention.

[0140] 1.Measuring methods for resin properties The physical properties of the resin were measured by the following methods.

[0141] <Melting point (Tm), glass transition temperature (Tg)> The melting point (Tm) and glass transition temperature (Tg) of the polyamide resin (A) were measured using a differential scanning calorimeter (DSC220C, manufactured by Seiko Instruments Inc.). Specifically, approximately 5 mg of the polyamide resin was sealed in an aluminum pan for measurement and set in the differential scanning calorimeter. The polyamide resin was then heated from room temperature to 350°C at 10°C / min. To completely melt the resin, the pan was held at 350°C for 3 minutes and then cooled to 30°C at 10°C / min. After leaving the pan at 30°C for 5 minutes, the pan was heated a second time to 350°C at 10°C / min. The temperature (°C) of the endothermic peak during this second heating was taken as the melting point (Tm) of the polyamide resin, and the inflection point corresponding to the glass transition was taken as the glass transition temperature (Tg).

[0142] <Heat of fusion (ΔH)> The heat of fusion (ΔH) of the polyamide resin was calculated from the area of ​​the exothermic peak of crystallization during the first heating process in accordance with JIS K 7122 (2012).

[0143] <Intrinsic viscosity [η]> The intrinsic viscosity [η] of the polyamide resin was calculated by dissolving 0.5 g of the polyamide resin in 50 ml of a 96.5% sulfuric acid solution, measuring the flow time of the resulting solution at 25°C ± 0.05°C using an Ubbelohde viscometer, and then calculating the intrinsic viscosity [η] based on the formula: [η] = ηSP / (C(1 + 0.205ηSP)). [η]: Intrinsic viscosity (dl / g) ηSP: Specific viscosity C: Sample concentration (g / dl) t: Number of seconds for sample solution to flow down (seconds) t0: Number of seconds the blank sulfuric acid flows (seconds) ηSP=(t-t0) / t0

[0144] 2. Material Preparation 2-1. Polyamide resin (A) A-1: PA6T / 66 (polyamide prepared in Synthesis Example 1 below) ·A-2:PA6I / 6T (G16, manufactured by EMS) A-3: PA6 (Amilan CM1017, manufactured by Toray Industries, Inc.)

[0145] The above PA6T / 66 was synthesized by the following method. [Synthesis Example 1] 2184 g (13.1 mol) of terephthalic acid, 2800 g (24.1 mol) of 1,6-diaminohexane, 1572 g (10.8 mol) of adipic acid, 5.7 g of sodium hypophosphite monohydrate as a catalyst, 36.5 g (0.30 mol) of benzoic acid as a molecular weight modifier, and 545 g of distilled water were placed in a 13.6 L autoclave and purged with nitrogen. Stirring was initiated at 190 °C, and the internal temperature was raised to 250 °C over 3 hours. At this time, the internal pressure of the autoclave was increased to 3.03 MPa. After the reaction was continued for 1 hour, the low-order condensation product was discharged into the atmosphere through a spray nozzle installed at the bottom of the autoclave and extracted. The extracted low-order condensation product was cooled to room temperature, crushed in a crusher to a particle size of 1.5 mm or less, and dried at 110 °C for 24 hours. The intrinsic viscosity [η] of the obtained low-order condensate was 0.15 dl / g.

[0146] Next, this low-order condensate was placed in a tray-type solid-state polymerization reactor, and after nitrogen substitution, the temperature was raised to 180°C over approximately 1 hour and 30 minutes. The low-order condensate was then reacted for 1 hour and 30 minutes, and the temperature was lowered to room temperature. The resulting prepolymer was then further melt-polymerized in a twin-screw extruder with a screw diameter of 30 mm and L / D = 36 at a barrel setting temperature of 330°C, a screw rotation speed of 200 rpm, and a resin feed rate of 6 kg / hour to obtain polyamide resin (A-1).

[0147] The resulting polyamide resin (A-1) had an intrinsic viscosity [η] of 1.00 dl / g, a melting point (Tm) of 310° C., a glass transition temperature (Tg) of 85° C., and a heat of fusion (ΔH) of 50 J / g. The resulting polyamide resin (A-1) had a composition in which the content of structural units derived from terephthalic acid among structural units derived from dicarboxylic acid was 55 mol %, the content of structural units derived from adipic acid was 45 mol %, and the content of structural units derived from 1,6-diaminohexane among structural units derived from diamine was 100 mol %.

[0148] The physical properties of each resin are shown in Table 1. [Table 1]

[0149] 2-2. Modified ethylene-α-olefin copolymer (B) Maleic anhydride-modified ethylene-1-butene copolymer (Tafmer MH5020, manufactured by Mitsui Chemicals, Inc., 1-butene content: 20 mol%)

[0150] 2-3. Phosphinate (C) Aluminum diethylphosphinate (EXOLIT OP1230, Clariant, phosphorus content: 23% by mass (catalog value), median diameter (D50): 10-50 μm)

[0151] 2-4. Nitrogen-containing (poly)phosphates (D) Melamine polyphosphate (Melapur 200, manufactured by BASF, median diameter: 4.5 μm, phosphorus content: 13% by mass)

[0152] 2-5. Inorganic filler (E) Glass fiber (ECS03T-262H, Nippon Electric Glass Co., Ltd.)

[0153] 2-6.Other ingredients 2-6-1. Lubricants 12-hydroxybarium stearate (BS-6, manufactured by Nitto Kasei Kogyo Co., Ltd.)

[0154] 2-6-2. Nucleating agent Talc (High Filler 5000PJ, manufactured by Matsumura Sangyo Co., Ltd., average particle size: 4.5 μm)

[0155] 2-6-3.Flame retardant synergists Flame retardant synergist: 1:6 boron dizinc undecaoxide (firebrake 500, Borax) Flame retardant aid 2: zinc oxide (ZINCA-20, manufactured by Sakai Chemical Industry Co., Ltd.)

[0156] 2-6-4. Coloring agents Masterbatch of PA6T / 66: 90% by mass, CB (carbon black): 10% by mass

[0157] 3. Preparation of polyamide resin composition [Examples 1 to 2, Comparative Examples 1 to 3] The above materials were mixed in a tumbler blender in the composition ratios (units: parts by mass) shown in Table 2, and melt-kneaded using a 30 mmφ vented twin-screw extruder at a cylinder temperature of 245°C and a main motor rotation speed of 200 rpm. The kneaded mixture was then extruded into strands and cooled in a water bath. The strands were then taken up in a pelletizer and cut to obtain pellet-shaped polyamide resin compositions 1 to 5.

[0158] [Examples 3 to 5, Comparative Examples 4 to 5] The above materials were mixed in a tumbler blender in the composition ratios (units: parts by mass) shown in Table 3, and melt-kneaded using a 30 mmφ vented twin-screw extruder at a cylinder temperature of 320°C and a main motor rotation speed of 360 rpm. The kneaded mixture was then extruded into strands and cooled in a water bath. The strands were then taken up in a pelletizer and cut to obtain pellet-shaped polyamide resin compositions 6 to 10.

[0159] 4. Evaluation The flame retardancy, low-temperature tensile elongation, and heat shock resistance of each of the polyamide resin compositions obtained in Examples 1 to 5 and Comparative Examples 1 to 5 were evaluated by the following methods. For 4-1. Flame retardancy and 4-2. Low-temperature tensile elongation, test specimens of shapes and sizes suitable for each test were prepared by the following methods.

[0160] <Test piece preparation conditions> (Polyamide resin compositions 1 to 5) The polyamide resin composition was vacuum-press molded to prepare a test piece. The vacuum-press molding conditions were as follows: Temperature: 265℃ Vacuum / Preheat / Press / Cooling time: 10 min / 3 min / 2 min / 4 min

[0161] (Polyamide resin compositions 6 to 10) The polyamide resin composition was injection molded to prepare test pieces under the following injection molding conditions. Molding machine: Tupearl TR40S3A (manufactured by Sodick Plastic Co., Ltd.) Molding machine cylinder temperature: 320℃ Mold temperature: 120℃

[0162] 4-1.Flame retardancy The polyamide resin composition was molded by the above method to prepare test pieces measuring 1 / 32 inch x 1 / 2 x 5 inches. Using the prepared test pieces, a vertical flame test was performed in accordance with the UL94 standard (UL Test No. UL94 dated June 18, 1991) to evaluate flame retardancy.

[0163] 4-2.Low temperature tensile elongation The polyamide resin composition was molded by the above method to prepare a strip-shaped test piece having a thickness of 1 mm. The obtained test piece was left to stand for 24 hours in an atmosphere at a temperature of 23°C and a relative humidity of 50%. Next, a tensile test was carried out in accordance with JIS K 7161:2014 in an atmosphere of a temperature of -40°C and a relative humidity of 50% at a tensile speed of 50 mm / min, and the tensile elongation (%) of the test piece at -40°C was measured.

[0164] 4-3.Heat shock resistance An insert member (54 mm × 54 mm × 2 mm) made of S45C as specified in JIS G4051:2016 was placed in a metal insert molding mold attached to an injection molding machine (SE75EV, manufactured by Sumitomo Heavy Industries, Ltd.) Next, the polyamide resin composition was injection molded into the mold under conditions of a cylinder setting temperature of 335°C, a mold temperature of 160°C, and an injection speed of 50 mm / sec to prepare a metal insert test piece.

[0165] Fig. 1A is a perspective view showing the shape of a test specimen prepared for evaluating heat shock resistance, Fig. 1B is a plan view of the test specimen, and Fig. 1C is a cross-sectional view of the test specimen taken along line A-A' shown in Fig. 1B. The numerical values ​​in Fig. 1B and Fig. 1C indicate dimensions (unit: mm). As shown in Figures 1A-1C, the top, bottom, and side surfaces of the insert were covered by a 56.4 mm x 57 mm rectangular resin section (1 mm thick on the top and bottom surfaces and 2 mm thick on the side surfaces (same thickness as the insert)) that was 1 mm larger than the four sides of the test specimen in a plan view toward the gate (Y direction in Figure 1B), 2 mm larger in the direction opposite the gate (opposite the Y direction in Figure 1B), and 1.2 mm larger in the outward direction of the remaining two sides (X direction and its opposite direction in Figure 1B). To hold the insert in the mold, the four sides of the test specimen were provided with cutouts in the shape of a right-angled isosceles triangle with two sides of 7 mm each, with the top and bottom surfaces of the test specimen uncovered by resin. The side surfaces of the test specimen at the cutouts were covered with resin. At the end of the resin part on the gate side, a resin reservoir measuring 2 mm (outward direction: X direction and the opposite direction) × 4 mm (opposite the Y direction) × 2 mm (thickness) was provided in the outward direction (X direction and the opposite direction in Figure 1B) perpendicular to the resin flow direction, which was formed continuously from the resin part covering the side surface of the test piece at the notch. In addition, a resin reservoir was provided at the end of the resin part facing the gate part to prevent the formation of a weld in the part of the resin part close to the insert member.

[0166] A heat shock test was performed on these test pieces using a thermal shock tester (manufactured by Satake Chemical Machinery Co., Ltd.), with one cycle consisting of holding at -40°C for 30 minutes and holding at 160°C for 30 minutes. The presence or absence of cracks was observed every five cycles, and the number of cycles until cracks occurred was measured. This measurement was performed five times for each test piece, and the average of the measured number of cycles was calculated. Note that a calculated number of 0 cycles indicates that cracks occurred immediately after molding, and a number of cycles of 1 or more indicates that no cracks occurred immediately after molding.

[0167] The compositions and evaluation results of the polyamide resin compositions of Examples 1 to 2 and Comparative Examples 1 to 3 are shown in Table 2, and the compositions and evaluation results of the polyamide resin compositions of Examples 3 to 5 and Comparative Examples 4 to 5 are shown in Table 3. The numerical values ​​of the compositions in Tables 2 and 3 are in parts by mass.

[0168] [Table 2]

[0169] [Table 3]

[0170] As shown in Table 2, when the phosphinate (C) is contained, the addition of the acid-modified ethylene-α-olefin copolymer (B) improves the impact resistance at low temperatures, but reduces the flame retardancy (comparison between Comparative Examples 2 and 3). In contrast, when both the phosphinate (C) and the nitrogen-containing (poly)phosphate (D) are contained, even when the acid-modified ethylene-α-olefin copolymer (B) is further contained, it is found that the impact resistance at low temperatures is improved while the flame retardancy is also well exhibited (see Examples 1 and 2).

[0171] As shown in Table 3, when the acid-modified ethylene-α-olefin copolymer (B) was not contained, the impact resistance at low temperatures and the heat shock resistance were both low (see Comparative Example 6).In addition, when the phosphinate (C) was contained but the nitrogen-containing (poly)phosphate (D) was not contained, the flame retardancy was low (see Comparative Example 5). In contrast, when both the phosphinate (C) and the nitrogen-containing (poly)phosphate (D) are contained, even when the acid-modified ethylene-α-olefin copolymer (B) is further contained, it is found that the impact resistance at low temperatures is increased, the heat shock resistance is also increased, and good flame retardancy is also exhibited (see Examples 3 to 5).

[0172] The results in Tables 2 and 3 show that even when an acid-modified ethylene-α-olefin copolymer (B) is contained, impact resistance and flame retardancy at low temperatures can be achieved simultaneously by containing both a phosphinate (C) and a nitrogen-containing polyphosphate (D). [Industrial Applicability]

[0173] The polyamide resin composition of the present invention can achieve both high flame retardancy and low-temperature impact resistance, and is therefore expected to broaden the applicability of polyamide resins to various uses and contribute to the further popularization of polyamide resins.

Claims

1. A polyamide resin (A), a modified ethylene / α-olefin copolymer (B) modified with an unsaturated carboxylic acid or a derivative thereof; a phosphinate (C); a nitrogen-containing (poly)phosphate (D); an inorganic filler (E); Including, Polyamide resin composition.

2. the mass ratio of the content of the nitrogen-containing (poly)phosphate (D) to the content of the phosphinate (C) is 0.05 or more and 0.5 or less; The polyamide resin composition according to claim 1.

3. a total content of the phosphinate (C) and the nitrogen-containing (poly)phosphate (D) is 10% by mass or more and 30% by mass or less, based on the total mass of the polyamide resin composition; The polyamide resin composition according to claim 1.

4. the mass ratio of the content of the nitrogen-containing (poly)phosphate (D) to the content of the modified ethylene / α-olefin copolymer (B) is 0.3 or more and 1.5 or less; The polyamide resin composition according to claim 1.

5. the content of the modified ethylene / α-olefin copolymer (B) is 1.00 mass% or more and 10.00 mass% or less, based on the total mass of the polyamide resin composition; The polyamide resin composition according to claim 1.

6. The polyamide resin (A) includes a polyamide resin (A-1) having a melting point measured by a differential scanning calorimeter (DSC) of 280°C or higher. The polyamide resin composition according to claim 1.

7. The polyamide resin (A-1) contains a structural unit (A-1a) derived from a dicarboxylic acid and a structural unit (A-1b) derived from a diamine, The structural unit (A-1a) derived from a dicarboxylic acid includes a structural unit derived from terephthalic acid, The diamine-derived structural unit (A-1b) includes a 1,6-diaminohexane-derived structural unit. The polyamide resin composition according to claim 6.

8. The polyamide resin (A) further contains a polyamide resin (A-2) having substantially no melting point. The polyamide resin composition according to claim 6.

9. The content of the inorganic filler (E) is 10.0 mass% or more and 50.0 mass% or less based on the total mass of the polyamide resin composition. The polyamide resin composition according to claim 1.

10. A molded article obtained by molding the polyamide resin composition according to any one of claims 1 to 9.

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