Polyamide resin composition and molding

Abstract

To provide a polyamide resin composition which is excellent in flame retardancy and mechanical strength of a composition, and is particularly excellent in drip suppression during a compression test and tensile test and weld strength when being formed into a molding.SOLUTION: A polyamide resin composition contains 20 to 70 mass% of (A) a polyamide resin, 10 to 35 mass% of (B) a flame retardant, 1 to 15 mass% of (C) an auxiliary flame retardant, and 10 to 60 mass% of (D) a glass fiber, wherein in fiber length distribution of (D) the glass fiber, with respect to the total mass of (D) the glass fiber, a content of (D) the glass fiber having a fiber length of 400 μm or more and less than 500 μm is 15 mass% or more and 25 mass% or less, and a content of (D) the glass fiber having a fiber length of less than 500 μm is 50 mass% or more and 60 mass% or less.SELECTED DRAWING: None

Description

Technical Field

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

Background Art

[0002] Polyamides represented by polyamide 6 (hereinafter sometimes abbreviated as "PA6") and polyamide 66 (hereinafter sometimes abbreviated as "PA66") are used in fields such as automotive parts, mechanical parts, and electrical and electronic parts because they are excellent in mechanical strength, heat resistance, etc. In particular, in the field of electrical and electronic parts, the required level of flame retardancy is high, and a higher level of flame retardant performance than the self-extinguishing property inherent to polyamide resins is required. For this reason, many studies have been made to meet the evaluation V-0 in the UL94 standard of Underwriters Laboratories.

[0003] As a typical example of such flame-retardant polyamide resins, flame-retardant polyamide materials using brominated polystyrene can be mentioned. For example, Patent Document 1 discloses a polyamide resin composition that is excellent in heat resistance, flame retardancy, and fluidity in a reflow soldering process and has good thermal stability during molding. Patent Document 2 discloses a polyamide resin composition in which the amount of gas generated during molding is significantly reduced and the mold corrosiveness is extremely low. Patent Document 3 discloses a polyamide resin composition that imparts toughness together with high flame retardancy and high weld strength.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 2

Patent Document 3

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, recently, due to the increasing complexity of the structure of electrical and electronic components, the components tend to be thinner. Therefore, materials with better flame retardancy and mechanical properties than before are increasingly required, and the inventions disclosed in the above documents do not necessarily satisfy the above properties. In addition, when glass fibers are added to a polyamide resin composition for the purpose of improving mechanical strength, breakage of the glass fibers often occurs during processing, and it may not meet the UL standard by causing dripping during the combustion test, but this has not been sufficiently studied in the above conventional technologies.

[0006] Therefore, an object of the present invention is to provide a polyamide resin composition excellent in flame retardancy and mechanical properties, and a molded article formed by molding the polyamide resin composition.

Means for Solving the Problems

[0007] That is, the present invention includes the following aspects. (1) A polyamide resin composition comprising (A) 20 to 70% by mass of a polyamide resin, (B) 10 to 35% by mass of a flame retardant, (C) 1 to 15% by mass of a flame retardant aid, and (D) 10 to 60% by mass of glass fibers, wherein in the fiber length distribution of the (D) glass fibers, the ratio of the (D) glass fibers having a fiber length of 400 μm or more and less than 500 μm to the total mass of the (D) glass fibers is 15% by mass or more and 25% by mass or less, and the ratio of the (D) glass fibers having a fiber length of less than 500 μm is 50% by mass or more and 60% by mass or less. (2) The polyamide resin composition according to (1), wherein the (A) polyamide resin is at least one selected from the group consisting of polyamide 6, polyamide 46, polyamide 66, polyamide 6T, and polyamide MXD6, and a copolymer polyamide containing at least one of these as a constituent component. (3) The polyamide resin composition according to (1) or (2), wherein the (B) flame retardant contains a halogen-based flame retardant. (4) The polyamide resin composition according to (3), wherein the halogen-based flame retardant contains one or more bromine-based flame retardants selected from the group consisting of PBDE-based, TBBA-based, polybenzene ring compounds, and brominated aromatic polymers. (5) The polyamide resin composition according to any one of (1) to (4), wherein the flame retardant aid (C) contains one or more selected from the group consisting of antimony oxides, tin oxides, iron oxides, metal hydroxides, metal borates, and silicones. (6) The polyamide resin composition according to any one of (1) to (5), wherein the average roundness of the cross section of the glass fiber (D) is 1 or more and less than 4. (7) A molded article characterized by molding the polyamide resin composition according to any one of (1) to (6).

Advantages of the Invention

[0008] According to the present invention, it is possible to provide a polyamide resin composition excellent in flame retardancy and mechanical strength, and a molded article formed by molding the polyamide resin composition.

Modes for Carrying Out the Invention

[0009] Hereinafter, modes for carrying out the present invention (hereinafter referred to as "the present embodiment") will be described in detail. It should be noted that the present invention is not limited to the following embodiments, and various modifications can be made within the scope of the gist thereof.

[0010] In this specification, the "polyamide resin" means a polymer compound having a "-CO-NH-" (amide) bond in the main chain.

[0011] <Polyamide Resin Composition> The polyamide resin composition of the present embodiment (hereinafter may be simply abbreviated as "resin composition") contains (A) a polyamide resin, (B) a flame retardant, (C) a flame retardant aid, and (D) glass fiber. The content of (A) polyamide resin in the polyamide resin composition is 20 to 70% by mass, preferably 45 to 65% by mass, more preferably 50 to 60% by mass in 100% by mass of the polyamide resin composition. The content of (B) flame retardant in the polyamide resin composition is 10 to 35% by mass, preferably 13 to 30% by mass, more preferably 15 to 25% by mass in 100% by mass of the polyamide resin composition. The content of (C) flame retardant aid in the polyamide resin composition is 1 to 15% by mass, preferably 2 to 13% by mass, more preferably 3 to 10% by mass in 100% by mass of the polyamide resin composition. The content of (D) glass fiber in the polyamide resin composition is 10 to 60% by mass, preferably 11 to 55% by mass, more preferably 12 to 50% by mass in 100% by mass of the polyamide resin composition.

[0012] In the polyamide resin composition of this embodiment, in the fiber length distribution of (D) glass fiber, the ratio of (D) glass fiber with a fiber length of 400 μm or more and less than 500 μm to the total mass of (D) glass fiber is 15% by mass or more and 25% by mass or less, and the ratio of (D) glass fiber with a fiber length of less than 500 μm is 50% by mass or more and 60% by mass or less. Preferably, in the fiber length distribution of (D) glass fiber, the ratio of (D) glass fiber with a fiber length of 400 μm or more and less than 500 μm to the total mass of (D) glass fiber is 15% by mass or more and 20% by mass or less, and the ratio of (D) glass fiber with a fiber length of less than 500 μm is 50% by mass or more and 55% by mass or less. When the fiber length distribution of (D) glass fiber in the polyamide resin composition is within the above range, the flame retardancy and mechanical strength of the molded body are excellent. The fiber length distribution of (D) glass fiber can be determined by the method described in the examples below.

[0013] As a method for making the fiber length distribution of (D) glass fiber in the polyamide resin composition fall within the above range, for example, a method is effective in which glass fiber having a weight average fiber length of 2.0 mm or more and 4.0 mm or less is used as a raw material, and the stress time integral value (a value obtained by accumulating the shear stress received by the resin during melt kneading by an extruder) during melt kneading is adjusted. As a method for adjusting the stress time integral value, for example, a method of adjusting the viscosity number (VN) of the polyamide resin composition and adjusting the screw design of the extruder is effective. For example, by inputting the screw shape, operating conditions, and resin physical properties of a twin screw extruder (manufactured by HASL) into a twin screw simulator, it is possible to calculate the stress time integral value. Generally, in order to increase the stress time integral value, a configuration is adopted in which many kneading disks and reverse disks are combined to apply shear stress to the kneaded product.

[0014] [(A) Polyamide resin] (A) The polyamide resin is not particularly limited hereinafter. For example, (a) a polyamide resin obtained by ring-opening polymerization of lactam; (b) a polyamide resin obtained by self-condensation of ω-aminocarboxylic acid; (c) a polyamide resin obtained by condensing diamine and dicarboxylic acid; and copolymers thereof, etc. may be mentioned. (A) The polyamide resin may be a single type or a combination of two or more types. Hereinafter, various raw materials of (A) polyamide resin will be described.

[0015] The lactam serving as the raw material of the above (a) polyamide resin is not particularly limited. For example, pyrrolidone, caprolactam, undecalactam, dodecalactam, etc. may be mentioned. The ω-aminocarboxylic acid serving as the raw material of the above (b) polyamide resin is not particularly limited. For example, ω-amino fatty acids, which are ring-opening compounds of the above lactam with water, etc. may be mentioned. Note that the above (a) polyamide resin or the above (b) polyamide resin may each be a product obtained by condensing two or more types of lactam or ω-aminocarboxylic acid in combination.

[0016] The diamine (monomer) used as a raw material for the above (c) polyamide resin is not particularly limited. For example, linear aliphatic diamines such as hexamethylenediamine and pentamethylenediamine; branched aliphatic diamines such as 2-methylpentanediamine and 2-ethylhexamethylenediamine; aromatic diamines such as p-phenylenediamine and m-phenylenediamine; alicyclic diamines such as cyclohexanediamine, cyclopentanediamine, and cyclooctanediamine can be mentioned. The dicarboxylic acid (monomer) used as a raw material for the above (c) polyamide resin is not particularly limited. For example, aliphatic dicarboxylic acids such as adipic acid, pimelic acid, and sebacic acid; aromatic dicarboxylic acids such as phthalic acid and isophthalic acid; alicyclic dicarboxylic acids such as cyclohexanedicarboxylic acid can be mentioned. The diamine and dicarboxylic acid as the above-mentioned monomers may be condensed either individually or in combination of two or more.

[0017] (A) The polyamide resin is not particularly limited. For example, polyamide 4 (poly-α-pyrrolidone), polyamide 6 (polycaproamide), polyamide 11 (polyundecanamide), polyamide 12 (polydodecanamide), polyamide 46 (polytetramethylene adipamide), polyamide 56 (polypentamethylene adipamide), polyamide 66 (polyhexamethylene adipamide), polyamide 610 (polyhexamethylene sebacamide), polyamide 612 (polyhexamethylene dodecamide), polyamide 1010 (polydecamethylene sebacamide), polyamide 1012 (polydecamethylene dodecamide), polyamide 6T (polyhexamethylene terephthalamide), polyamide 9T (polynonamethylene terephthalamide), polyamide MXD6 (polymetaxylylene adipamide), polyamide 6I (polyhexamethylene isophthalamide), and copolyamides containing these as constituent components can be mentioned.

[0018] Also, the copolyamide is not particularly limited, and examples thereof include copolymers of polyamide 66 and polyamide 6T, copolymers of polyamide 66 and polyamide 6I, copolymers of polyamide 6T and polyamide 6I, and the like.

[0019] Among the polyamides listed above, the (A) polyamide resin is preferably at least one selected from the group consisting of polyamide 6, polyamide 46, polyamide 66, polyamide 6T, polyamide 6I, polyamide MXD6, and copolyamides containing at least one of these as a constituent component, and more preferably at least one selected from the group consisting of polyamide 6, polyamide 46, polyamide 66, polyamide 6T, polyamide MXD6, and copolyamides containing at least one of these as a constituent component. By using such an (A) polyamide resin, the mechanical strength and heat rigidity of the obtained molded body tend to be more excellent.

[0020] Generally, an amino group or a carboxy group is present at the terminal group of the polyamide resin. Although not particularly limited, the ratio of the amino terminal group amount to the total amount of the amino terminal group amount and the carboxy terminal group amount of the (A) polyamide resin [amino terminal group amount / (amino terminal group amount + carboxy terminal group amount)] is preferably 0.3 or more and less than 1.0, more preferably 0.3 or more and 0.8 or less, and even more preferably 0.3 or more and 0.6 or less. When the ratio of the terminal group amount is within the above range, the molded body obtained from the polyamide resin composition tends to be more excellent in color tone, mechanical strength, and vibration fatigue resistance characteristics.

[0021] (A) The amino terminal group amount of the polyamide resin is preferably 10 μmol / g or more and 100 μmol / g or less, more preferably 15 μmol / g or more and 80 μmol / g or less, and even more preferably 30 μmol / g or more and 80 μmol / g or less. When the amino terminal group amount is within the above range, the mechanical strength of the polyamide resin composition tends to be more excellent.

[0022] Here, as the method for measuring the amount of amino-terminal groups and the amount of carboxy-terminal groups in this specification, for example, 1 the 1H-NMR method, the titration method, etc. can be mentioned. 1 In the 1H-NMR method, it can be determined by the integral value of the characteristic signal corresponding to each terminal group. In the titration method, for the amino-terminal group, for example, a method of titrating a phenol solution of the polyamide resin with 0.1N hydrochloric acid, and for the carboxy-terminal group, for example, a method of titrating a benzyl alcohol solution of the polyamide resin with 0.1N sodium hydroxide, etc. can be mentioned.

[0023] The method for adjusting the amount (terminal concentration) of terminal groups of the polyamide resin is not particularly limited, and known methods can be used. As the adjustment method, for example, a method using a terminal modifier can be mentioned. As a specific example, at the time of polymerization of the polyamide, one or more terminal modifiers selected from the group consisting of a monoamine compound, a diamine compound, a monocarboxylic acid compound, and a dicarboxylic acid compound are added so as to have a predetermined terminal concentration. The timing of adding the terminal modifier to the solvent is not particularly limited as long as it fulfills its original function as a terminal modifier. For example, it may be when adding the above-mentioned raw materials of the polyamide to the solvent.

[0024] The above-mentioned monoamine compound is not particularly limited. For example, aliphatic monoamines such as methylamine, ethylamine, propylamine, butylamine, hexylamine, octylamine, decylamine, stearylamine, dimethylamine, diethylamine, dipropylamine, dibutylamine; alicyclic monoamines such as cyclohexylamine, dicyclohexylamine; aromatic monoamines such as aniline, toluidine, diphenylamine, naphthylamine, and any mixture thereof, etc. can be mentioned. Among them, from the viewpoints of reactivity, boiling point, stability of the blocked terminal, and price, etc., butylamine, hexylamine, octylamine, decylamine, stearylamine, cyclohexylamine or aniline is preferable. These may be used alone or in combination of two or more.

[0025] The above diamine compound is not particularly limited. For example, linear aliphatic diamines such as hexamethylenediamine and pentamethylenediamine; branched aliphatic diamines such as 2-methylpentanediamine and 2-ethylhexamethylenediamine; aromatic diamines such as p-phenylenediamine and m-phenylenediamine; and alicyclic diamines such as cyclohexanediamine, cyclopentanediamine, and cyclooctanediamine can be mentioned. These may be used alone or in combination of two or more.

[0026] The above monocarboxylic acid compound is not particularly limited. For example, aliphatic monocarboxylic acids such as acetic acid, propionic acid, butyric acid, valeric acid, caproic acid, caprylic acid, lauric acid, tridecylic acid, myristic acid, palmitic acid, stearic acid, pivalic acid, and isobutyric acid; alicyclic monocarboxylic acids such as cyclohexanecarboxylic acid; and aromatic monocarboxylic acids such as benzoic acid, toluic acid, α-naphthalenecarboxylic acid, β-naphthalenecarboxylic acid, methylnaphthalenecarboxylic acid, and phenylacetic acid can be mentioned. These carboxylic acid compounds may be used alone or in combination of two or more.

[0027] The above dicarboxylic acid compound is not particularly limited. For example, aliphatic dicarboxylic acids such as malonic acid, dimethylmalonic acid, succinic acid, glutaric acid, adipic acid, 2-methyladipic acid, trimethyladipic acid, pimelic acid, 2,2-dimethylglutaric acid, 3,3-diethylsuccinic acid, azelaic acid, sebacic acid, and suberic acid; alicyclic dicarboxylic acids such as 1,3-cyclopentanedicarboxylic acid and 1,4-cyclohexanedicarboxylic acid; and aromatic dicarboxylic acids such as isophthalic acid, 2,6-naphthalenedicarboxylic acid, 2,7-naphthalenedicarboxylic acid, 1,4-naphthalenedicarboxylic acid, 1,4-phenylenedioxydiacetic acid, 1,3-phenylenedioxydiacetic acid, diphenic acid, diphenylmethane-4,4'-dicarboxylic acid, diphenylsulfone-4,4'-dicarboxylic acid, and 4,4'-biphenyldicarboxylic acid can be mentioned. These may be used alone or in combination of two or more.

[0028] [(B) Flame retardant] The (B) flame retardant used in this embodiment is added to improve the flame retardant properties. It is preferable that the (B) flame retardant includes a halogen-based flame retardant. Examples of the halogen-based flame retardant include PBDE-based such as decabromodiphenyl ether, TBBA-based including derivatives such as tetrabromobisphenol A, polybenzene ring compounds such as poly(2,6-dibromophenylene oxide), brominated polystyrene, and brominated aromatic polymers such as 2,6- or 2,4-dibromophenol homopolymer. It is preferably at least one kind containing a bromine-based flame retardant.

[0029] Regarding the above PBDE-based, decabromodiphenyl ether (10-brominated), octabromodiphenyl ether (8-brominated), pentabromodiphenyl ether (5-brominated), etc. can be mentioned.

[0030] Regarding the above TBBA-based, derivatives of tetrabromobisphenol A (TBBA) such as epoxy oligomer, carbonate oligomer, bis(dibromopropyl ether), bis(aryl ether), etc. can be mentioned.

[0031] Regarding the above polybenzene ring compounds, bis(pentabromophenyl)ethane, 1,2-bis(2,4,6-tribromophenoxy)ethane, 2,4,6-tris(2,4,6-tribromophenoxy)-1,3,5-triazine, etc. can be mentioned.

[0032] From the viewpoints of fluidity and thermal stability, the weight average molecular weight Mw of brominated polystyrene is preferably 1000 to 10000, more preferably 1000 to 5000. Also, from the viewpoints of fluidity and thermal stability, the molecular weight distribution (weight average molecular weight Mw / number average molecular weight Mn) of brominated polystyrene is preferably 1.0 to 2.0, more preferably 1.05 to 1.30. In addition, in this specification, the weight-average molecular weight and number-average molecular weight of brominated polystyrene can be measured by gel permeation chromatography (GPC), specifically, for example, they can be measured under the following conditions. <Measurement of Molecular Weight of Brominated Polystyrene> GPC Measurement Conditions GPC apparatus: HLC-8320GPC (manufactured by Tosoh Corporation) Columns: TSKgel GMHHR-H (7.8 mm I.D. × 30 cm) × 2 (manufactured by Tosoh Corporation) Eluent: Chloroform (product with amylenes added for HPLC, manufactured by Fujifilm Wako Pure Chemical Corporation) Detector: Differential refractive index detector (RI detector), polarity=(+) Flow rate: 1.0 mL / min. Column temperature: 40 °C Sample concentration: 2 mg / mL Sample injection volume: 100 μL Sample pretreatment: Weigh the sample, add a predetermined amount of eluent, let it stand overnight at room temperature, and heat and dissolve it at 50 °C for 1 hour. Then, gently shake and filter it through a 0.45 μm PTFE cartridge filter. Calibration curve: Use a third-order approximation curve using standard polystyrene (PS) (manufactured by Tosoh Corporation). Therefore, the obtained value will be the molecular weight in terms of PS.

[0033] [(C) Flame Retardant Aid] The polyamide resin composition of this embodiment further contains (C) a flame retardant aid. Thereby, a polyamide resin composition with even more excellent flame retardancy can be obtained.

[0034] (C) The flame retardant aid is not particularly limited. For example, antimony oxides such as antimony trioxide, antimony tetroxide, antimony pentoxide, and sodium antimonate; tin oxides such as tin monoxide and tin dioxide; iron oxides such as ferric oxide and γ-iron oxide; metal hydroxides such as magnesium hydroxide and aluminum hydroxide; metal borates such as zinc borate, magnesium borate, calcium borate, and aluminum borate; and silicone and the like can be mentioned. These (C) flame retardant aids may be used alone or in combination of two or more kinds. (C) From the viewpoint of the flame retardant effect, the flame retardant aid is preferably at least one selected from antimony oxides, tin oxides, iron oxides, and metal borates, more preferably antimony oxides, and particularly preferably antimony trioxide.

[0035] In order to enhance the flame retardant effect, the average particle size of the (C) flame retardant aid is preferably 0.01 to 10 μm. In the present specification, the average particle size of the (C) flame retardant aid can be measured using a laser diffraction scattering method particle size distribution measuring device or a precision particle size distribution measuring device.

[0036] [(D) Glass fiber] (D) The cross-section of the glass fiber may be circular or flat (elliptical, cocoon-shaped, etc.), but from the viewpoint of low warpage, the flat shape is preferred.

[0037] When the cross-section is circular, from the viewpoints of mechanical strength and appearance, the number average fiber diameter of the (D) glass fiber is preferably 3 μm or more and 30 μm or less, more preferably 9 μm or more and 20 μm or less, and even more preferably 12 μm or more and 19 μm or less. In the case of a flat shape, from the viewpoints of mechanical strength, appearance, and low warpage, the average minor axis of the glass fiber is preferably 3 μm or more and 15 μm or less, more preferably 4 μm or more and 10 μm or less, and even more preferably 5 μm or more and 9 μm or less. In this specification, the fiber diameter (minor axis) can be measured, for example, by heating and incinerating pellets of the polyamide resin composition at a temperature equal to or higher than the decomposition temperature of the polyamide resin composition, photographing the remaining ash using a microscope, and measuring the fiber diameter (minor axis) of the glass fiber. The number-average fiber diameter can be calculated by averaging the obtained measurement values. Here, the minor axis and major axis refer to the length of the short side (minor axis) and the length of the long side (major axis) of the rectangle with the minimum area circumscribing the cross-section of the glass fiber when assuming a rectangle circumscribing the cross-section of the glass fiber.

[0038] As a concept representing the flatness of the glass fiber, when the ratio of the minor axis to the major axis (major axis / minor axis) is expressed as the circularity, it is preferable that the average circularity of the cross-section of the (D) glass fiber is 1 or more and less than 4, more preferably 1.05 or more and less than 3, still more preferably 1.1 or more and less than 2, and particularly preferably 1.15 or more and 1.8 or less. The average circularity in the case where the cross-section is circular is 1. In this specification, the average circularity is a value obtained by photographing the cross-section of the (D) glass fiber using a microscope, calculating the circularity from the measurement results of the minor axis and major axis for 50 or more randomly selected fibers, and averaging them.

[0039] Regardless of whether the cross-section is circular or flat, from the viewpoints of excellent mechanical strength and appearance, the average cross-sectional area of the (D) glass fiber is 50μm 2 or more and 350μm 2 or less, preferably 100μm 2 or more and 300μm 2 or less, more preferably 120μm 2 or more and 250μm 2 or less is still more preferable. In this specification, the average cross-sectional area is a value obtained by photographing the cross-section of the (D) glass fiber using a microscope, measuring the cross-sectional area for 50 or more randomly selected fibers, and averaging them.

[0040] From the perspective of mechanical strength, the weight-average fiber length of the (D) glass fiber in the polyamide resin composition is preferably 100 μm or more and 750 μm or less, more preferably 200 μm or more and 650 μm or less, and even more preferably 400 μm or more and 600 μm or less. In this specification, the fiber length can be measured, for example, by heating and burning the pellets of the polyamide resin composition at a temperature equal to or higher than the decomposition temperature of the polyamide resin composition, photographing the remaining ash using a microscope, and measuring the length of the glass fiber. The weight-average fiber length can be calculated from the obtained measured values using the following formula. [Weight-average fiber length] = [Sum of the squares of the glass fiber lengths] / [Total of the glass fiber lengths]

[0041] Specific compositions of the glass fiber are not limited to the following, but examples include E-glass (alkali-free glass) composition, C-glass (alkali-containing glass) composition, S-glass (reinforced glass) composition, alkali-resistant glass composition, and the like. Among these, E-glass is preferred from the perspective of easy availability.

[0042] (D) The glass fiber preferably has at least one of a surface treatment agent and a sizing agent. For example, at least one of a surface treatment agent and a sizing agent may be applied to the (D) glass fiber. By the (D) glass fiber having at least one of a surface treatment agent and a sizing agent, it tends to be particularly excellent in processability, especially defibrillation property.

[0043] (D) The surface treatment agent for glass fibers is not particularly limited. For example, it is preferable to use a silane coupling agent. The silane coupling agent is not particularly limited. For example, aminosilanes such as γ-aminopropyltriethoxysilane, γ-aminopropyltrimethoxysilane, N-β-(aminoethyl)-γ-aminopropylmethyldimethoxysilane; mercaptosilanes such as γ-mercaptopropyltrimethoxysilane, γ-mercaptopropyltriethoxysilane; epoxy silanes; vinyl silanes can be mentioned. Among these, aminosilanes are preferable. Note that the surface treatment agent may be used alone or in combination of two or more.

[0044] (D) The sizing agent for glass fibers is not particularly limited. For example, epoxy resins, polyurethane resins, homopolymers of acrylic acid, copolymers of acrylic acid and other copolymerizable monomers, homopolymers of acrylic acid, copolymers of acrylic acid and other copolymerizable monomers, salts of the homopolymers or copolymers of acrylic acid with primary, secondary or tertiary amines, copolymers containing a carboxylic anhydride-containing unsaturated vinyl monomer and an unsaturated vinyl monomer excluding the carboxylic anhydride-containing unsaturated vinyl monomer as constituent units, etc. can be mentioned. These may be used alone or in combination of two or more. Among these, copolymers containing a carboxylic anhydride-containing unsaturated vinyl monomer and an unsaturated vinyl monomer excluding the carboxylic anhydride-containing unsaturated vinyl monomer as constituent units, epoxy resins, polyurethane resins, or combinations thereof are preferable, and copolymers containing a carboxylic anhydride-containing unsaturated vinyl monomer and an unsaturated vinyl monomer excluding the carboxylic anhydride-containing unsaturated vinyl monomer as constituent units, polyurethane resins, or combinations thereof are more preferable. By using such a sizing agent, the mechanical strength of the resin composition tends to be further improved.

[0045] The carboxylic anhydride-containing unsaturated vinyl monomer is not particularly limited. For example, maleic anhydride, itaconic anhydride, citraconic anhydride, etc. can be mentioned. Among these, maleic anhydride is preferable.

[0046] The unsaturated vinyl monomer other than the carboxylic acid anhydride-containing unsaturated vinyl monomer means an unsaturated vinyl monomer different from the carboxylic acid anhydride-containing unsaturated vinyl monomer. Such unsaturated vinyl monomers are not particularly limited, and examples thereof include styrene, α-methylstyrene, ethylene, propylene, butadiene, isoprene, chloroprene, 2,3-dichlorobutadiene, 1,3-pentadiene, cyclooctadiene, methyl methacrylate, methyl acrylate, ethyl acrylate, ethyl methacrylate, and the like. Among these, styrene or butadiene is preferred.

[0047] Preferred copolymers containing the carboxylic acid anhydride-containing unsaturated vinyl monomer and the unsaturated vinyl monomer excluding the carboxylic acid anhydride-containing unsaturated vinyl monomer as constituent units are not particularly limited, and examples thereof include copolymers of maleic anhydride and butadiene, copolymers of maleic anhydride and ethylene, copolymers of maleic anhydride and styrene, and mixtures thereof.

[0048] In addition, the lower limit of the weight average molecular weight of the copolymer containing the carboxylic acid anhydride-containing unsaturated vinyl monomer and the unsaturated vinyl monomer other than the carboxylic acid anhydride-containing unsaturated vinyl monomer as constituent units is preferably 2,000, more preferably 5,000. The upper limit of the weight average molecular weight is preferably 1,000,000, more preferably 500,000. When the weight average molecular weight is within the above range, the fluidity of the resin composition tends to be further improved. In this specification, the weight average molecular weight of the above copolymer can be measured by GPC.

[0049] The epoxy resin is not particularly limited, but for example, those having at least two or more glycidyl groups are preferably used, and among them, epoxy resins obtained by reacting bisphenol with epihalohydrin are more preferred. The molar equivalent of the epoxy group in the epoxy resin is preferably 180 g / mol equivalent or more, and more preferably 450 g / mol equivalent or more and 1900 g / mol equivalent or less. When the epoxy equivalent is within the above range, the bundling property of (D) glass fiber tends to be further improved.

[0050] The polyurethane resin is not particularly limited as long as it is generally used as a bundling agent for (D) glass fiber. For example, those synthesized from isocyanates such as m-xylylene diisocyanate (XDI), 4,4'-methylenebis(cyclohexyl isocyanate) (HMDI), and isophorone diisocyanate (IPDI), and polyester-based or polyether-based diols can be mentioned.

[0051] The weight average molecular weight of the above homopolymer of acrylic acid is preferably 1,000 or more and 90,000 or less, more preferably 1,000 or more and 25,000 or less, and even more preferably 1,000 or more and 25,000 or less. In this specification, the weight average molecular weight of the homopolymer of acrylic acid can be measured by a standard method using GPC.

[0052] Regarding the copolymer of acrylic acid and other copolymerizable monomers, the monomers forming the copolymer with acrylic acid are not particularly limited. For example, monomers having at least one of a hydroxyl group and a carboxyl group can be mentioned. Such monomers having at least one of a hydroxyl group and a carboxyl group are not particularly limited. For example, one or more selected from the group consisting of acrylic acid, maleic acid, methacrylic acid, vinyl acetic acid, crotonic acid, isocrotonic acid, fumaric acid, itaconic acid, citraconic acid, and mesaconic acid can be mentioned (however, the case of only acrylic acid is excluded). It is preferable to have one or more ester-based monomers among the above-mentioned monomers.

[0053] Examples of the primary, secondary, or tertiary amines that can form salts with at least one of the homopolymers and copolymers of acrylic acid are not particularly limited, and include, for example, triethylamine, triethanolamine, glycine, and the like. From the viewpoints of improving the stability of the mixed solution with other co-used agents (such as silane coupling agents) and reducing the amine odor, the degree of neutralization is preferably 20% or more and 90% or less, more preferably 30% or more and 80% or less, and even more preferably 40% or more and 60% or less.

[0054] The weight average molecular weight of the polymer of acrylic acid that forms a salt with the primary, secondary, or tertiary amine is not particularly limited, but a range of 3,000 or more and 50,000 or less is preferable. When the weight average molecular weight is at least the above lower limit value, the bundling property of the glass fiber tends to be further improved. Also, when the weight average molecular weight is at most the above upper limit value, the mechanical properties of the resin composition tend to be further improved.

[0055] When treating (D) glass fiber with at least one of a surface treatment agent and a bundling agent, it is preferable to use a lubricant. The lubricant is not particularly limited, and for example, any ordinary liquid or solid lubricant material according to the purpose can be used. Examples of such lubricants include, but are not limited to, animal and plant-based or mineral-based waxes such as carnauba wax and lanolin wax; fatty acid amides, fatty acid esters, or fatty acid ethers; and surfactants such as aromatic esters or aromatic ethers.

[0056] ((D) Surface treatment method of glass fiber) The surface-treated (D) glass fiber can be obtained, for example, by applying (imparting) at least one of the above surface treatment agent and bundling agent to (D) glass fiber using a known method such as a roller-type applicator in a known glass fiber manufacturing process, and continuously reacting by drying the obtained fiber strand.

[0057] Note that the state of the (D) glass fiber is not particularly limited. For example, the glass fiber strand may be used as roving as it is, or it may be used as chopped strand cut to a length of about 2 mm or more and 5 mm or less through a further cutting process. Note that the drying of the strand may be performed after the cutting process or before the cutting process.

[0058] The adhesion amount of at least one of the above surface treatment agent and sizing agent is preferably 0.2% by mass or more and 3% by mass or less, more preferably 0.2% by mass or more and 2% by mass or less, and even more preferably 0.3% by mass or more and 2% by mass or less as a solid content ratio with respect to 100% by mass of the (D) glass fiber. When the adhesion amount of at least one of the surface treatment agent and sizing agent is at least the above lower limit value, the bundling property of the glass fiber tends to be further improved. On the other hand, when the adhesion amount of at least one of the surface treatment agent and sizing agent is at most the above upper limit value, the thermal stability of the resin composition tends to be further improved.

[0059] (D) The glass fiber may be a single type alone, or may be a combination of two or more types with different cross-sectional shapes, average cross-sectional areas, glass compositions, surface treatment agents, sizing agents, etc.

[0060] <Method for producing polyamide resin composition> The method for producing the polyamide resin composition of the present embodiment is not particularly limited, but a method of kneading the (A) polyamide resin in a molten state by a single-screw or multi-screw extruder can be used. For example, it is preferable to use a twin-screw extruder equipped with an upstream supply port and a downstream supply port, supply the (A) polyamide resin, (B) flame retardant, and (C) flame retardant aid from the upstream supply port and melt them, and then supply the (D) glass fiber from the downstream supply port and use a method of melt-kneading. Also, when using the roving of the (D) glass fiber, it can be compounded by a known method.

[0061] As described above, by adjusting the weight-average fiber length of the glass fiber raw material, the stress-time integral value during melt kneading, etc., and controlling the breakage of (D) glass fiber during the production of the resin composition, it is possible to provide a polyamide resin composition excellent in flame retardancy and mechanical strength when formed into a molded article, and a molded article formed by molding the polyamide resin composition.

[0062] <Molded article> The molded article of this embodiment is formed by molding the polyamide resin composition of the above-described embodiment, and is excellent in flame retardancy and mechanical strength.

[0063] Examples of the molding method include extrusion molding, injection molding, vacuum molding, blow molding, injection compression molding, decorative molding, molding with other materials, gas assist injection molding, foaming injection molding, low pressure molding, ultra-thin wall injection molding (ultra-high speed injection molding), and in-mold composite molding (insert molding, out-insert molding), etc.

[0064] The molded article of this embodiment contains the above-described polyamide resin composition, is excellent in the surface appearance stability of the molded article under severe molding conditions, the mechanical properties of the weld part, toughness, heat resistance, and flame retardancy, and can be used for various applications. For example, it can be preferably used in the fields of automobiles, electric and electronic, machinery and industry, office equipment, and aviation and space.

Examples

[0065] Hereinafter, this embodiment will be described more specifically by way of examples and comparative examples, but this embodiment is not limited only to these examples.

[0066] First, the raw materials, measurement methods, and evaluation methods used in the examples and comparative examples are shown below.

[0067] <Raw materials> [(A) Polyamide resin] (A-1) Polyamide 66 Viscosity number (VN): 141 ml / kg, amino end groups: 40 μmol / g, carboxy end groups: 80 μmol / g (A-2) Polyamide 66 Viscosity number (VN): 120 ml / kg, Amino end group: 27 μmol / g, Carboxy end group: 84 μmol / g

[0068] [(B) Flame retardant] (B-1) Brominated polystyrene (manufactured by Albemarle, trade name: SAYTEX® HP-3010PST (Mw = 3557, Mn = 2978, Mw / Mn = 1.19) (B-2) 2,6- or 2,4-dibromophenol homopolymer (manufactured by Daiichi Kogyo Seiyaku Co., Ltd., trade name: Pyrogard® SR-460B) [Measurement of molecular weight of brominated polystyrene] GPC measurement conditions GPC apparatus: HLC-8320GPC (manufactured by Tosoh) Column: TSKgel GMHHR-H (7.8 mm I.D. × 30 cm) × 2 (manufactured by Tosoh) Eluent: Chloroform (amylene-added product for HPLC manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) Detector: Differential refractive index detector (RI detector), polarity=(+) Flow rate: 1.0 mL / min. Column temperature: 40 °C Sample concentration: 2 mg / mL Sample injection volume: 100 μL Sample pretreatment: The sample was weighed, a predetermined amount of eluent was added, and it was left standing overnight at room temperature and then heated and dissolved at 50 °C for 1 hour. Then, it was gently shaken and filtered through a 0.45 μm PTFE cartridge filter. In addition, no insoluble matter was confirmed visually in the sample solution for all samples. Calibration curve: A third-order approximation curve using standard polystyrene (PS) (manufactured by Tosoh) was used. Therefore, the obtained value is the molecular weight in terms of PS.

[0069] [(C) Flame retardant aid] (C-1) Antimony trioxide (manufactured by Campion, trade name: Antimony trioxide, average particle size 0.8 - 1.0 μm) (C-2) Zinc borate (manufactured by Mizusawa Chemical Industry Co., Ltd., trade name: Alkanex® FRC-500)

[0070] [(D) Glass fiber] (D) Glass fiber Chopped strand shape, cross-sectional shape: circular (average roundness: 1), number average fiber diameter: 10.5 μm, weight average fiber length: 3.0 mm, tensile modulus of monofilament: 84 GPa, surface treatment: silane coupling agent (0.35 mass% in solid content ratio)

[0071] [Physical property 1] (Terminal concentration) The amino group terminal concentration of the polyamide resin was measured as follows by neutralization titration. First, 3.0 g of the obtained polyamide was dissolved in 100 mL of a 90 mass% aqueous phenol solution. Then, using the obtained solution, titration was performed with 0.025 N hydrochloric acid to determine the amino group terminal concentration (μmol / g). The end point was determined from the indicated value of the pH meter.

[0072] The carboxyl group terminal concentration of the polyamide resin was measured as follows by neutralization titration. First, 4.0 g of the obtained polyamide was dissolved in 50 mL of benzyl alcohol. Then, using the obtained solution, titration was performed with 0.1 N NaOH to determine the carboxyl group terminal concentration (μmol / g). The end point was determined from the color change of the phenolphthalein indicator.

[0073] [Physical property 2] (Diameter of the cross-section of the glass fiber) The diameter (μm) of the cross-section of the glass fiber was calculated by photographing the cross-section of the glass fiber using a scanning electron microscope (SEM) and measuring and averaging the diameters of 50 randomly selected fibers.

[0074] [Physical property 3] (Weight average fiber length of the glass fiber) The pellets of the polyamide resin compositions produced in the following Examples and Comparative Examples were heat-treated by incineration by heating in an electric furnace at 650 °C for 2 hours. From the residue, 20,000 glass fibers were arbitrarily selected, and the fiber lengths of the 20,000 glass fibers were measured using SEM photographs at a magnification of 1000 times. Next, the weight-average fiber length (μm) was determined using the following formula. Also, the fiber length distribution of the glass fibers (the ratios of fiber lengths less than 300 μm, 300 μm or more and less than 400 μm, 400 μm or more and less than 500 μm, 500 μm or more and less than 1000 μm, 1000 or more) was also determined. [Weight-average fiber length] = [Sum of squares of glass fiber lengths] / [Total of glass fiber lengths]

[0075] <Evaluation method> [Evaluation 1] <Tensile strength> An injection molding machine, NEXIV manufactured by Nissei Plastic Industrial Co., Ltd., was used. The cylinder temperature was set to the melting point of polyamide + 20 °C, and the mold temperature was set to the glass transition temperature of polyamide + 20 °C. Molding was performed under the injection molding conditions of injection for 10 seconds and cooling for 10 seconds using each polyamide composition to obtain a molded body (ISO test piece). Using the ISO test piece, the tensile strength was measured at a tensile speed of 5 mm / min according to ISO 527. The measured value was taken as the average value of n = 6.

[0076] [Evaluation 2] <Weld strength> In an injection molding machine (NEXIV manufactured by Nissei Plastic Industrial Co., Ltd.) equipped with a mold such that molten resin flows in from both ends in the length direction of a shape with a length of 127 mm, a width of 12.7 mm, and a thickness of 1.6 mm, and a weld is formed at the center in the length direction, the cylinder temperature was set to the melting point of polyamide + 20 °C, and the mold temperature was set to the glass transition temperature of polyamide + 20 °C, and molding was performed to obtain a test piece. A tensile test was carried out in a method compliant with ISO 527, except that the molded test piece had a chuck distance of 50 mm and a tensile speed of 50 mm / min, and the tensile strength was determined. The measured value was taken as the average value of n = 6.

[0077] [Evaluation 3] <Evaluation of flame retardancy> The measurement was carried out using the UL94 (standard defined by Underwriters Laboratories Inc., USA) method. The test specimens (length: 127 mm, width: 12.7 mm, thickness: 0.3 mm) were prepared by attaching a UL test specimen mold (mold temperature = glass transition temperature of polyamide + 20°C) to an injection molding machine (PS40E manufactured by Nissei Plastic Industrial Co., Ltd.) and molding the polyamide resin composition with the cylinder temperature set at the melting point of polyamide + 20°C. The injection pressure was set at the full filling pressure for molding the UL test specimen + 2% pressure. The flame retardant grade was in accordance with the UL94 standard (vertical combustion test). The outline is shown below. V-0: Total combustion time of 5 test specimens is 50 seconds or less, maximum combustion time is 10 seconds or less, no dripping V-1: Total combustion time of 5 test specimens is 250 seconds or less, maximum combustion time is 30 seconds or less, no dripping V-2: Total combustion time of 5 test specimens is 250 seconds or less, maximum combustion time is 30 seconds or less, dripping occurs

[0078] <Manufacture of Polyamide Resin Composition> [Examples 1 - 8] (Manufacture of Polyamide Resin Composition) A twin-screw extruder (ZSK-26MC: manufactured by Coperion GmbH (Germany)) with an L / D (length of the extruder barrel / diameter of the extruder barrel) = 48 (total number of barrels: 12. Hereinafter, the barrels are represented as C1, C2, C3, C4, C5, C6, C7, C8, C9, C10, C11, and C12 in order. The barrel configuration is as shown below.) having an upstream supply port in the first barrel from the upstream side and a downstream supply port in the seventh barrel was used.

[0079] (Barrel Configuration) Upstream supply port: C1 Plasticization section: C2 - C5 Transport section: C6 Downstream supply port: C7 Kneading section: C8 - 12

[0080] In the above twin-screw extruder, the temperature from the upstream supply port to the extrusion port (die) was set to 280°C, the screw rotation speed was 300 rpm, (degassing degree -0.06 MPa), and the discharge rate was 25 kg / hour. Under such conditions, the polyamide resin, flame retardant, and flame retardant aid were supplied from the upstream supply port, and the glass fiber was supplied from the downstream supply port so as to have the composition and compounding amounts shown in Table 1 below. Next, the kneading conditions of the twin-screw extruder were set as the screw pattern A shown below, and these were melt-kneaded to produce pellets of each polyamide resin composition.

[0081] (Screw pattern A) · Upstream supply port 1: C1 · Plasticizing section 2: C4 - C5 (Configuration: A combination of 7 kneading disks with the same length as the barrel diameter D and then 1 reverse disk of 0.4D, length approximately 190 mm) · Downstream supply port 3: C7 · Kneading section 4: C8 - C12 (Configuration: A combination of 7 kneading disks with the same length as the barrel diameter D and then 1 reverse disk of 0.4D, length approximately 190 mm)

[0082] (Stress time integral value) The stress time integral value during melt-kneading was calculated using a Twin Screw Simulator manufactured by HASL. The following low-density polyethylene LDPE data attached to the simulation software was used. (Conditions) · Software: Twin Screw Simulator manufactured by HASL (Ver. 6.0.0) · Discharge rate: 25 kg / hr · Screw rotation speed: 300 rpm · Barrel temperature: 280°C · Inlet temperature 30°C · Heat transfer coefficient: 0.6 W / cm 2 / K · Analysis method: Unfilled analysis (exit resin pressure 1 MPa) · Feed: Top · Recipe: Calculated based on the LDPE included with the software · Other parameters were analyzed using the default values · Model fitting software: Materialfit (Ver. 4.0.0) manufactured by HASL · Resin data: Fitted with Cross model · Melt density: 770 kg / m 2 · Solid density: 960 kg / m 2 · Melt specific heat: 2250 J / kg / K · Solid specific heat: 2303 J / kg / K · Thermal conductivity: 0.25 W / m / K · Melt temperature: 130 °C · Nerton viscosity: 1000 Pa·s · Latent heat: 201189 J / kg · Adaptation of Tadmor model

[0083] [Comparative Example 1] (Manufacture of polyamide resin composition) The above polyamide resin, flame retardant, and flame retardant aid were supplied from the upstream supply port, and glass fiber was supplied from the downstream supply port so as to have the composition and blending amounts described in Table 1 below. Next, these were melt-kneaded under the screw pattern B shown below for the kneading conditions of the twin-screw extruder to produce pellets of the polyamide resin composition.

[0084] (Screw pattern B) · Upstream supply port 1: C1 · Plasticizing section 2: C4 - C5 (Composition: A combination of 10 kneading disks with the same length as the barrel diameter D and then 1 reverse disk of 0.4D, length approximately 270 mm) · Downstream supply port 3: C7 · Kneading section 4: C8 - C12 (Composition: A combination of 10 kneading disks with the same length as the barrel diameter D and then 1 reverse disk of 0.4D, length approximately 270 mm above)

[0085] [Comparative Example 2] (Manufacture of polyamide resin composition) The polyamide resin, flame retardant, and flame retardant aid were supplied from the upstream supply port, and the glass fiber was supplied from the downstream supply port so as to have the composition and blending amounts described in Table 1 below. Next, these were melt-kneaded under the screw pattern C shown below for the kneading conditions of the twin-screw extruder to produce pellets of the polyamide resin composition.

[0086] (Screw pattern C) · Upstream supply port 1: C1 · Plasticizing section 2: C4 - C5 (Configuration: A combination of 3 kneading disks with the same length as the barrel diameter D and then 1 reverse disk of 0.4D, length approximately 90 mm) · Downstream supply port 3: C7 · Kneading section 4: C8 - C12 (Configuration: A combination of 7 kneading disks with the same length as the barrel diameter D and then a reverse disk of 0.4D, length approximately 270 mm)

[0087] Regarding the obtained polyamide resin composition, the physical properties were measured using the above method, and various evaluations were performed. The results are shown in Table 1.

[0088]

Table 1

[0089] From Table 1, polyamide resin compositions (Examples 1 - 8) produced with screw pattern A, containing (A) 20 - 70% by mass of polyamide resin, (B) 10 - 35% by mass of flame retardant, (C) 1 - 15% by mass of flame retardant aid, and (D) 10 - 60% by mass of glass fiber, in the fiber length distribution of (D) glass fiber in the polyamide resin composition, the content of (D) glass fiber with a fiber length of 400 μm or more and less than 500 μm is 15% by mass or more and 25% by mass or less, and the content of (D) glass fiber with a fiber length of less than 500 μm is 50% by mass or more and 60% by mass or less, can suppress dripping during combustion in the UL94 combustion test by controlling the glass fiber length during the production of the composition by adjusting the weight average fiber length of the glass fiber raw material and the stress-time integral value during melt-kneading, and a molded body excellent in mechanical strength (tensile strength, weld strength) was obtained while achieving V - 0. Also, in the (D) glass fiber, the smaller the proportion of fiber lengths shorter than the weight average fiber length (less than 300 μm, 300 μm or more and less than 400 μm), the less likely it is to drip during combustion.

[0090] On the other hand, from Table 1, in the polyamide resin compositions produced with screw patterns B and C (Comparative Examples 1 and 2), in the fiber length distribution of the glass fiber, the proportion of 400 μm or more and less than 500 μm was outside the range of 15% by mass or more and less than 25% by mass. It is considered that the glass fibers are entangled in a network structure due to the remaining glass fibers of appropriate length, and dripping can be suppressed. However, in Comparative Examples 1 and 2, the network structure cannot be maintained due to the presence of many short glass fibers, resulting in dripping during combustion, which deteriorates the flame retardancy and also causes a decrease in mechanical strength.

Industrial Applicability

[0091] The polyamide resin composition of the present invention is excellent in the flame retardancy and mechanical strength of the composition, and is particularly excellent in suppressing dripping during the combustion test, tensile test and weld strength when formed into a molded body. Therefore, it can be suitably used in the fields of automobiles, electric and electronic, machinery and industry, office equipment, aerospace, etc.

Claims

1. (A) 20 to 70 mass% of a polyamide resin, (B) 10 to 35 mass% of a flame retardant, (C) 1 to 15 mass% of a flame retardant auxiliary, and (D) 10 to 60 mass% of a glass fiber, In the fiber length distribution of the (D) glass fibers, a ratio of the (D) glass fibers having a fiber length of 400 μm or more and less than 500 μm to a total mass of the (D) glass fibers is 15 mass% or more and 25 mass% or less, and a ratio of the (D) glass fibers having a fiber length of less than 500 μm is 50 mass% or more and 60 mass% or less. A polyamide resin composition comprising:

2. The polyamide resin composition according to claim 1, wherein the (A) polyamide resin is one or more selected from the group consisting of polyamide 6, polyamide 46, polyamide 66, polyamide 6T, polyamide MXD6, and copolymer polyamides containing at least one of these as a constituent component.

3. The polyamide resin composition according to claim 1 , wherein the (B) flame retardant comprises a halogen-based flame retardant.

4. 4. The polyamide resin composition according to claim 3, wherein the halogen-based flame retardant comprises one or more bromine-based flame retardants selected from the group consisting of PBDE-based, TBBA-based, polybenzene ring compounds, and brominated aromatic polymers.

5. 2. The polyamide resin composition according to claim 1, wherein the (C) flame retardant auxiliary comprises at least one selected from the group consisting of antimony oxides, tin oxides, iron oxides, metal hydroxides, metal borates, and silicones.

6. 2. The polyamide resin composition according to claim 1, wherein the cross-sectional average circularity of the glass fibers (D) is 1 or more and less than 4.

7. A molded article obtained by molding the polyamide resin composition according to any one of claims 1 to 6.

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