Polyamide resin composition, and molding

Abstract

To provide a polyamide resin composition excellent in fire-resistance, extrusion processability, and molding processability in a thin wall, particularly in drip suppression when testing burning, and flow characteristic and toughness when molding.SOLUTION: A polyamide resin composition includes: (A) 20-70 mass% of a polyamide; (B) 10-35 mass% of brominated polystyrene; (C) 1-15 mass% of a flame-retardant auxiliary; (D) 10-60 mass% of an inorganic filler; (E) 0.1-1.5 mass% of a copolymer of an aromatic vinyl compound and an α,β-unsaturated dicarboxylic acid anhydride; and (F) 1-5 mass% of polyphenylene ether modified by an α,β-unsaturated dicarboxylic acid anhydride, where the bromine content of (B) the brominated polystyrene is 64-71 mass%, and the weight average molecular weight is 1,000-10,000.SELECTED DRAWING: None

Description

[Technical field]

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

[0002] Polyamides such as polyamide 6 (hereinafter sometimes abbreviated as "PA6") and polyamide 66 (hereinafter sometimes abbreviated as "PA66") are used in fields such as automobile parts, machine parts, and electrical and electronic parts because of their excellent mechanical strength and heat resistance. In particular, the demand for flame retardancy is high for electrical and electronic component applications, and a higher level of flame retardancy is required than the inherent self-extinguishing property of polyamide resins. For this reason, there has been much research into meeting the V-0 rating in the UL94 standard set by Underwriters Laboratories.

[0003] A representative example of such a flame-retardant polyamide resin is a flame-retardant polyamide material using brominated polystyrene. For example, Patent Document 1 discloses a polyamide resin composition that is excellent in heat resistance, flame retardancy, and flowability in a reflow soldering process, and also has improved thermal stability during molding. Furthermore, Patent Document 2 discloses a polyamide resin composition that generates a reduced amount of gas during molding and is extremely less corrosive to a mold. Furthermore, Patent Document 3 discloses a polyamide resin composition that is endowed with toughness in addition to high flame retardancy and high weld strength. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] International Publication No. 2006 / 123469 [Patent Document 2] Japanese Patent Application Publication No. 10-168307 [Patent Document 3] JP 2007-291250 A Summary of the Invention [Problem to be solved by the invention]

[0005] However, in recent years, there has been a trend toward thinner-walled electric and electronic components due to the increasingly complex structures of those components. In such cases, in addition to the conventional tensile strength, flame retardancy, and molding fluidity, improvements in weld properties, toughness, and thermal decomposition resistance are highly desired, and the above-mentioned documents have not necessarily been satisfactory.

[0006] Therefore, an object of the present invention is to provide a polyamide resin composition which is excellent in extrusion processability, molding processability, mechanical properties and flame retardancy, as well as in flow properties during molding, toughness and drip suppression during combustion tests. [Means for solving the problem]

[0007] Means for Solving the Problems The present inventors have conducted intensive research to solve the above problems and have found that by incorporating a brominated polystyrene having a specific molecular weight into a polyamide resin composition and using a compatibilizer in combination, it is possible to improve the flow characteristics and toughness of a polyamide resin composition during molding and to suppress dripping during a flame test, thereby completing the present invention.

[0008] That is, the present invention is as follows. (1): A polyamide resin composition comprising: (A) 20-70% by mass of polyamide; (B) 10-35% by mass of brominated polystyrene; (C) 1-15% by mass of a flame retardant auxiliary; (D) 10-60% by mass of an inorganic filler; (E) 0.1-1.5% by mass of a copolymer of an aromatic vinyl compound and an α,β-unsaturated dicarboxylic anhydride; and (F) 1-5% by mass of a polyphenylene ether modified with an α,β-unsaturated dicarboxylic anhydride, The polyamide resin composition (B) has a bromine content of 64 to 71 mass % and a weight average molecular weight of 1,000 to 10,000 in the brominated polystyrene.

[0009] (2): The polyamide resin composition according to (1), characterized in that the α,β-unsaturated dicarboxylic anhydride component contained in the (E) copolymer of an aromatic vinyl compound and an α,β-unsaturated dicarboxylic anhydride is 1 to 40 mass % based on the total amount of the (E).

[0010] (3): The polyamide resin composition according to (1) or (2), characterized in that the (E) copolymer of an aromatic vinyl compound and an α,β-unsaturated dicarboxylic acid anhydride has a weight average molecular weight of 10,000 to 250,000.

[0011] (4): The polyamide resin composition according to any one of (1) to (3), characterized in that the α,β-unsaturated dicarboxylic anhydride component contained in the (F) α,β-unsaturated dicarboxylic anhydride-modified polyphenylene ether is 0.2 to 1.0 mass % based on the total amount of the (F).

[0012] (5) The polyamide resin composition according to any one of (1) to (4), wherein the melting point of the (A) polyamide is 200° C. or higher and 270° C. or lower.

[0013] (6): A molded article, characterized by using the polyamide resin composition according to (1) or (2). Effect of the Invention

[0014] According to the present invention, it is possible to provide a polyamide resin composition which is excellent in extrusion processability, molding processability, mechanical properties and flame retardancy, as well as in flow properties during molding, toughness and suppression of dripping during a combustion test. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0015] Hereinafter, an embodiment of the present invention (hereinafter, referred to as "the present embodiment") will be described in detail. The present invention is not limited to the following embodiments, and can be practiced in various modifications within the scope of the present invention. In this specification, "polyamide" means a polymer having an amide (-NHCO-) ​​group in the main chain.

[0016] The polyamide resin composition of the present embodiment contains (A) 20 to 70 mass% of a polyamide, (B) 10 to 35 mass% of a brominated polystyrene, (C) 1 to 15 mass% of a flame retardant auxiliary, (D) 10 to 60 mass% of an inorganic filler, (E) 0.1 to 1.5 mass% of a copolymer of an aromatic vinyl compound and an α,β-unsaturated dicarboxylic acid anhydride, and (F) 1 to 5 mass% of a polyphenylene ether modified with an α,β-unsaturated dicarboxylic acid anhydride.

[0017] [(A) Polyamide] Examples of the polyamide (A) contained in the polyamide resin composition of the present embodiment include polycondensates of dicarboxylic acids and diamines, ring-opening polymers of cyclic lactams, and polycondensates of aminocarboxylic acids. Specifically, aliphatic polyamides such as poly(caprolactam) (hereinafter abbreviated as polyamide 6), poly(hexamethylene adipamide) (hereinafter abbreviated as polyamide 66), poly(tetramethylene adipamide) (hereinafter abbreviated as polyamide 46), poly(hexamethylene sebacamide) (hereinafter abbreviated as polyamide 610), poly(hexamethylene dodecamide) (hereinafter abbreviated as polyamide 612), poly(undecamethylene adipamide) (hereinafter abbreviated as polyamide 116), poly(undecalactam) (hereinafter abbreviated as polyamide 11), and poly(dodecalactam) (hereinafter abbreviated as polyamide 12) and poly(metaxylylene adipamide) (hereinafter abbreviated as poly Examples of polyamides that contain an aromatic component include polyamides such as poly(hexamethylene terephthalamide) (hereinafter abbreviated as polyamide 6T), poly(hexamethylene isophthalamide) (hereinafter abbreviated as polyamide 6I), poly(nonamethylene terephthalamide) (hereinafter abbreviated as polyamide 9T), poly(dodecamethylene terephthalamide) (hereinafter abbreviated as polyamide 12T), and poly(tetramethylene isophthalamide) (hereinafter abbreviated as polyamide 4I), as well as copolymers and mixtures of the above-mentioned aliphatic polyamides, copolymers of polyamides containing an aromatic component, and copolymers of aliphatic polyamides and polyamides containing an aromatic component.

[0018] If the melting point of the polyamide (A) is too high, the flame retardant will decompose during melt processing, increasing the amount of carbonized matter (hereinafter referred to as black spots) in the pellets and the amount of gaseous components, which will decrease melt processability and deteriorate the flame retardant efficiency. If the melting point is too low, the heat resistance of the molded product, such as HDT (deflection temperature under load), will decrease. Therefore, the melting point of the polyamide (A) is preferably 180°C or higher and 330°C or lower, and more preferably 200°C or higher and 270°C or lower. Examples of such (A) polyamides include polyamide 66, polyamide MXD6, 66 / 6I copolymer polyamide, 66 / 6 copolymer polyamide, 6I / 6T copolymer polyamide, 66 / 6I / 6T terpolymer polyamide, 66 / 6I / 6 terpolymer polyamide, and 6 / 6I / 6T terpolymer polyamide. Also included are polyamide resins having a melting point of 200° C. or more and 270° C. or less that are mixed with low-melting point polyamides such as these polyamides and polyamide 6.

[0019] More preferably, the (A) polyamide is polyamide 66, 66 / 6 copolymer polyamide, or 66 / 6I copolymer polyamide, which are excellent in moldability and physical properties, and also includes polyamide resins having a melting point of 240° C. or more and 270° C. or less that are mixed with these polyamides, polyamide 6I, or polyamide 6. Most preferably, it is polyamide 66.

[0020] The molecular weight of the polyamide (A) may be within a moldable range. Polyamides having a relative viscosity (RV) in the range of 10 to 70 as determined in accordance with ASTM D789 are particularly preferred, as they have good molding fluidity and can maintain a high level of flame retardancy. From the viewpoint of toughness, the relative viscosity (RV) of the polyamide (A) is more preferably in the range of 30 to 60, and most preferably 40 to 50. The relative viscosity (RV) is measured using 90% formic acid as a solvent, at a concentration of 3 g (polyamide) sample / 30 ml formic acid, at a temperature of 25°C.

[0021] The (A) polyamide generally has an amino group or a carboxy group at its terminal group. The ratio of the amount of amino terminal groups to the total molar amount of the amount of amino terminal groups and the amount of carboxy terminal groups of the (A) polyamide [amount of amino terminal groups / (amount of amino terminal groups+amount of carboxy terminal groups)] is preferably 0.2 or more and less than 1.0, more preferably 0.1 or more and 0.5 or less, and even more preferably 0.2 or more and 0.4 or less. By having the ratio of the amount of terminal groups within the above range, the mechanical strength and flowability obtained from the polyamide resin composition tend to be more excellent.

[0022] The content of the polyamide (A) in the polyamide composition of the present embodiment is not particularly limited, but can be 20% by mass or more and 70% by mass or less, or 23% by mass or more and 65% by mass or less, or 25% by mass or more and 60% by mass or less, based on 100% by mass of the polyamide resin composition.

[0023] [(B) Brominated polystyrene] The brominated polystyrene (B) contained in the polyamide resin composition of the present embodiment is added to improve flame retardant properties. In order to impart flame retardancy, flowability, and mechanical properties of the welds to the polyamide resin composition of the present embodiment, it is necessary to use a brominated polystyrene having a specific bromine content and a specific molecular weight.

[0024] The method for producing the (B) brominated polystyrene is not particularly limited, and examples thereof include a method in which a styrene monomer is polymerized to produce polystyrene, and then the benzene ring of the polystyrene is brominated, and a method in which a brominated styrene monomer (bromostyrene, dibromostyrene, tribromostyrene, etc.) is polymerized to produce the polystyrene.

[0025] In this embodiment, the bromine content in the (B) brominated polystyrene is 64 to 71% by mass. By making the bromine content in the (B) brominated polystyrene 64% by mass or more, the amount of bromine required for flame retardancy can be satisfied with a small amount of the (B) brominated polystyrene blended, and a polyamide resin composition having excellent heat resistance, flowability, toughness, low water absorption, and rigidity, and excellent flame retardancy can be obtained without impairing the properties of the (A) polyamide. In addition, by making the bromine content in the (B) brominated polystyrene 71% by mass or less, a polyamide resin composition that is unlikely to undergo thermal decomposition during melt processing such as extrusion or molding, can suppress gas generation, and is excellent in heat discoloration resistance can be obtained. From the same viewpoint, the bromine content in the (B) brominated polystyrene is more preferably 65 to 69% by mass. The bromine content in brominated polystyrene can be determined by burning it in a flask filled with high-purity oxygen, collecting the generated gas in an absorption liquid, and quantifying it by a known method using ion chromatography.

[0026] Furthermore, the (B) brominated polystyrene preferably has a specific molecular weight, and in order to improve fluidity, the weight average molecular weight is preferably 1,000 to 10,000, and more preferably 1,000 to 5,000. The weight-average molecular weight can be determined by measurement using GPC (gel permeation chromatography). When the weight-average molecular weight of (B) brominated polystyrene is 1000 or more, it is difficult to thermally decompose during extrusion processing, and the productivity and flame retardancy after molding are improved. On the other hand, when the weight-average molecular weight of (B) brominated polystyrene is 10000 or less, the compatibility with (A) polyamide, (E) copolymer of aromatic vinyl compound and α,β-unsaturated dicarboxylic acid anhydride (F) α,β-unsaturated dicarboxylic acid anhydride-modified polyphenylene ether is increased, and the flame retardancy and toughness tend to be improved.

[0027] The component of the brominated polystyrene (B) having a weight average molecular weight of 1000 to 10000 preferably has a molecular weight distribution (Mw / Mn) of 1.0 to 2.0, more preferably 1.05 to 1.30. By satisfying the above molecular weight distribution, higher flowability during molding and mechanical properties of the welds can be obtained.

[0028] The content of the brominated polystyrene (B) in the polyamide composition of this embodiment is 10 to 35% by mass. By making the content of the brominated polystyrene (B) 10% by mass or more, a polyamide resin composition having excellent flame retardancy can be obtained. In addition, by making the content of the brominated polystyrene (B) 35% by mass or less, it is possible to suppress the generation of decomposition gas during melt kneading, the decrease in fluidity during molding, and the adhesion of contaminating substances to the molding die. Furthermore, it is possible to suppress the decrease in mechanical properties such as toughness and rigidity and the appearance of the molded product.

[0029] [(C) Flame retardant synergist] The polyamide resin composition of the present embodiment further contains a flame retardant auxiliary (C), which makes it possible to provide a polyamide resin composition with even more excellent flame retardancy.

[0030] The flame retardant auxiliary (C) used in this embodiment is not particularly limited, and examples thereof include antimony oxides such as diantimony trioxide, diantimony tetraoxide, diantimony pentaoxide, 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 silicones. These flame retardant auxiliary (C) may be used alone or in combination of two or more.

[0031] From the viewpoint of flame retardant effect, the (C) flame retardant auxiliary is preferably at least one selected from antimony oxides, tin oxides, iron oxides, and metal borates, more preferably antimony oxides, and particularly preferably diantimony trioxide.

[0032] In order to improve the flame retardant effect, it is preferable to use a flame retardant auxiliary (C) having an average particle size of 0.01 to 10 μm. The average particle size can be measured using a laser diffraction scattering particle size distribution measuring device or a precision particle size distribution measuring device.

[0033] The content of the flame retardant aid (C) in the polyamide composition of the present embodiment is 1 to 15 mass %, preferably 1.5 to 9 mass %, based on 100 mass % of the polyamide resin composition. By including the flame retardant aid (C) in the above range, a polyamide resin composition having even better flame retardancy can be obtained. In addition, by setting the content of the flame retardant aid (C) to 15 mass % or less, a decrease in flowability during molding and a decrease in the appearance of a molded product can be suppressed. In addition, a polyamide resin composition having excellent toughness and the like can be obtained without impairing the properties of the polyamide resin composition having excellent mechanical properties such as toughness and rigidity.

[0034] [(D) Inorganic filler] The polyamide resin composition of the present embodiment further contains an inorganic filler (D), which allows the polyamide resin composition to have even more excellent mechanical properties such as toughness and rigidity.

[0035] The (D) inorganic filler used in the present embodiment is not particularly limited, and examples thereof include glass fibers, carbon fibers, calcium silicate fibers, potassium titanate fibers, glass flakes, talc, kaolin, mica, hydrotalcite, calcium carbonate, zinc carbonate, calcium hydrogen phosphate, wollastonite, silica, zeolite, alumina, boehmite, titanium oxide, silicon oxide, magnesium oxide, calcium silicate, sodium aluminosilicate, magnesium silicate, ketjen black, acetylene black, furnace black, carbon nanotubes, graphite, brass, copper, silver, aluminum, nickel, iron, calcium fluoride, montmorillonite, swellable fluoromica, and apatite. As the (D) inorganic filler, one type may be used, or two or more types may be used in combination.

[0036] As the (D) inorganic filler, from the viewpoints of rigidity, strength, and the like, preferred are glass fiber, carbon fiber, glass flake, talc, kaolin, mica, calcium carbonate, calcium hydrogen phosphate, wollastonite, silica, carbon nanotubes, graphite, calcium fluoride, montmorillonite, swellable fluoromica, apatite, and the like.

[0037] As the (D) inorganic filler, glass fiber or carbon fiber is more preferable, and among glass fibers and carbon fibers, those having a number average fiber diameter of 3 to 30 μm, a weight average fiber length of 100 to 750 μm, and an aspect ratio (L / D) of the weight average fiber length (L) to the number average fiber diameter (D) of 10 to 100 are more preferably used from the viewpoint of expressing high properties.

[0038] As the inorganic filler (D), glass fibers are more preferable, and among glass fibers, those having a number average fiber diameter of 3 to 30 μm, a weight average fiber length of 10 to 500 μm, and the aspect ratio (L / D) of 3 to 100 are even more preferably used.

[0039] The number average fiber diameter and weight average fiber length of the (D) inorganic filler can be measured by dissolving a molded product of a polyamide resin composition in a solvent in which polyamide is soluble, such as formic acid, and then arbitrarily selecting, from the insoluble components obtained, inorganic fillers having, for example, 100 or more fibers, and observing them with an optical microscope, a scanning electron microscope, or the like.

[0040] The content of the inorganic filler (D) in the polyamide resin composition of the present embodiment is 10 to 60 mass %, preferably 13 to 50 mass %, and more preferably 15 to 40 mass %, based on 100 mass % of the polyamide resin composition. By including the (D) inorganic filler in an amount of 10% by mass or more, the mechanical properties such as strength and rigidity of the polyamide resin composition are favorably improved. Furthermore, by setting the content of the inorganic filler to 60% by mass or less, an increase in resin temperature is suppressed, and a polyamide resin composition having excellent extrusion processability and moldability can be obtained.

[0041] [(E) Copolymer of aromatic vinyl compound and α,β-unsaturated dicarboxylic acid anhydride] The polyamide resin composition of the present embodiment contains (E) a copolymer of an aromatic vinyl compound and an α,β-unsaturated dicarboxylic acid anhydride. The α,β-unsaturated dicarboxylic acid anhydride includes, for example, a compound represented by the following general formula (1).

[0042] [ka] In the general formula (1), R 1 and R 2 are each independently a hydrogen atom or an alkyl group having 1 to 3 carbon atoms.

[0043] Examples of the α,β-unsaturated dicarboxylic anhydride include maleic anhydride and methylmaleic anhydride, and maleic anhydride is preferred. Examples of the polymer containing an α,β-unsaturated dicarboxylic anhydride as a copolymerization component include a copolymer of an aromatic vinyl compound and an α,β-unsaturated dicarboxylic anhydride.

[0044] Moreover, examples of the aromatic vinyl compound include compounds represented by the following general formula (2).

[0045] [ka] In the general formula (2), R 3 and R 4 are each independently a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, and k is an integer of 1 to 5. Examples of the aromatic vinyl compound include styrene, α-methylstyrene, and p-methylstyrene, with styrene being preferred.

[0046] In this embodiment, when the polymer containing the α,β-unsaturated dicarboxylic anhydride contains an aromatic vinyl compound component, it is considered that the aromatic vinyl compound component has affinity with the brominated polystyrene (B), and the α,β-unsaturated dicarboxylic anhydride portion has affinity with or reacts with the polyamide (A), thereby helping to disperse the brominated polystyrene (B) in the polyamide matrix and enabling it to be finely dispersed.

[0047] The proportions of the aromatic vinyl compound component and the α,β-unsaturated dicarboxylic anhydride component in the (E) copolymer of an aromatic vinyl compound and an α,β-unsaturated dicarboxylic anhydride are preferably 60 to 99% by mass for the aromatic vinyl compound component and 1 to 40% by mass for the α,β-unsaturated dicarboxylic anhydride component, from the viewpoints of flame retardancy, extrusion processability, fluidity, thermal decomposition resistance, etc. The proportion of the α,β-unsaturated dicarboxylic anhydride component is more preferably 5 to 30% by mass, and even more preferably 8 to 20% by mass.

[0048] The weight average molecular weight of the (E) copolymer of an aromatic vinyl compound and an α,β-unsaturated dicarboxylic acid anhydride is preferably 10,000 to 250,000 from the viewpoints of flame retardancy, extrusion processability, etc., and more preferably 80,000 to 200,000 from the viewpoints of fluidity and thermal decomposition resistance.

[0049] The content of the (E) copolymer of aromatic vinyl compound and α,β-unsaturated dicarboxylic anhydride in the polyamide resin composition of this embodiment is 0.1 to 1.5 mass%, preferably 0.15 to 1 mass%, more preferably 0.2 to 0.7 mass%, based on 100 mass% of the polyamide resin composition, from the viewpoint of strand stability and flowability during extrusion. By containing the (E) aromatic vinyl compound in the above range, the fine dispersion effect of the (B) brominated polystyrene in the polyamide resin composition due to compatibilization can be enhanced, and a polyamide resin composition excellent in the improvement of flame retardancy and strength due to the drip suppression effect can be obtained.

[0050] [(F) α,β-unsaturated dicarboxylic anhydride modified polyphenylene ether] The polyamide resin composition of the present embodiment contains (F) polyphenylene ether modified with an α,β-unsaturated dicarboxylic anhydride. By containing (F) polyphenylene ether modified with an α,β-unsaturated dicarboxylic anhydride, the effect of finely dispersing (B) brominated polystyrene in the polyamide resin composition due to compatibilization can be improved.

[0051] Examples of the polyphenylene ether modified with the α,β-unsaturated dicarboxylic anhydride include polyphenylene ether based on a polyphenylene ether represented by the following general formula (3) (R5 and R6 each represent an alkyl group having 1 to 4 carbon atoms, and n is 60 to 300) and having an α,β-unsaturated dicarboxylic anhydride structure as a part of the substituent. [ka]

[0052] Preferred specific examples of the polyphenylene ether represented by the above formula (I) include poly(2,6-dimethylphenylene-1,4-ether), poly(2-methyl-6-ethylphenylene-1,4-ether), poly(2,6-diethylphenylene-1,4-ether), poly(2-methyl-6-n-propylphenylene-1,4-ether), etc. Examples of the α,β-unsaturated dicarboxylic acid anhydride include maleic anhydride and methylmaleic anhydride, with maleic anhydride being preferred.

[0053] The modification rate of (F) α,β-unsaturated dicarboxylic anhydride-modified polyphenylene ether with α,β-unsaturated dicarboxylic anhydride is preferably 0.2 to 1.0%, more preferably 0.3 to 0.6%, from the viewpoints of flame retardancy and weld strength.

[0054] The content of the polyphenylene ether modified with an α,β-unsaturated dicarboxylic anhydride (F) in the polyamide resin composition of this embodiment is 1 to 5 mass %, preferably 2 to 3 mass %, based on 100 mass % of the polyamide resin composition. By including the polyphenylene ether modified with an α,β-unsaturated dicarboxylic anhydride (F) in the above range, the effect of finely dispersing the brominated polystyrene (B) in the polyamide resin composition due to compatibilization can be enhanced, and a polyamide resin composition having excellent flame retardancy improvement and strength improvement effects due to drip suppression effects can be obtained.

[0055] [Other ingredients] The polyamide resin composition of the present embodiment may contain the following components (other components) as necessary.

[0056] (Moldability improver) If necessary, a moldability improver may be added to the polyamide resin composition of the present embodiment, within a range that does not impair the object of the present embodiment. The moldability improver is not particularly limited, but examples thereof include higher fatty acids, higher fatty acid metal salts, higher fatty acid esters, and higher fatty acid amides.

[0057] Examples of the higher fatty acid include saturated or unsaturated, linear or branched aliphatic monocarboxylic acids having 8 to 40 carbon atoms, such as stearic acid, palmitic acid, behenic acid, erucic acid, oleic acid, lauric acid, and montanic acid. Among these, stearic acid and montanic acid are preferred.

[0058] The higher fatty acid metal salt is a metal salt of the higher fatty acid. As the metal element of the metal salt, the elements of Groups 1, 2 and 3 of the Periodic Table, zinc, aluminum, etc. are preferred, and the elements of Groups 1 and 2, such as calcium, sodium, potassium and magnesium, and aluminum, etc. are more preferred. Examples of higher fatty acid metal salts include calcium stearate, aluminum stearate, zinc stearate, magnesium stearate, calcium montanate, sodium montanate, calcium palmitate, and the like. Among these, metal salts of montanic acid and metal salts of stearic acid are preferred.

[0059] The higher fatty acid ester is an esterification product of the higher fatty acid and an alcohol. An ester of an aliphatic carboxylic acid having 8 to 40 carbon atoms and an aliphatic alcohol having 8 to 40 carbon atoms is preferred. Examples of fatty alcohols include stearyl alcohol, behenyl alcohol, and lauryl alcohol. Examples of higher fatty acid esters include stearyl stearate and behenyl behenate.

[0060] The higher fatty acid amide is an amide compound of the higher fatty acid. Examples of higher fatty acid amides include stearic acid amide, oleic acid amide, erucic acid amide, ethylene bisstearylamide, ethylene bisoleylamide, N-stearylstearylamide, and N-stearylerucic acid amide. As the higher fatty acid amide, preferred are stearic acid amide, erucic acid amide, ethylene bisstearylamide, and N-stearyl erucic acid amide, and more preferred are ethylene bisstearylamide and N-stearyl erucic acid amide.

[0061] These higher fatty acids, higher fatty acid metal salts, higher fatty acid esters, and higher fatty acid amides may each be used alone or in combination of two or more.

[0062] (Alkaline earth metals) If necessary, an alkaline earth metal substance may be added to the polyamide resin composition of this embodiment, provided that the object of this embodiment is not impaired. Examples of alkaline earth metal oxides used in the present invention include calcium oxide and barium oxide. The alkaline earth metal oxides may be used alone or as a mixture of two kinds. Among them, calcium oxide is particularly preferred, since it has a particularly large gas generation suppressing effect even with a small amount of addition, and does not cause a decrease in physical properties or deterioration in moldability. stomach.

[0063] (deterioration inhibitor) If necessary, a degradation inhibitor may be added to the polyamide resin composition of the present embodiment for the purpose of preventing thermal degradation and discoloration when heated, improving heat aging resistance, and weather resistance, within a range that does not impair the object of the present embodiment.

[0064] Examples of deterioration inhibitors include, but are not limited to, copper compounds such as copper acetate and copper iodide; phenol-based stabilizers such as hindered phenol compounds; phosphite-based stabilizers; hindered amine-based stabilizers; triazine-based stabilizers; and sulfur-based stabilizers. These deterioration inhibitors may be used alone or in combination of two or more.

[0065] (Other resins) If necessary, other resins may be added to the polyamide resin composition of the present embodiment, as long as the object of the present embodiment is not impaired. Such resins are not particularly limited, but examples thereof include thermoplastic resins and rubber components described below.

[0066] Examples of the thermoplastic resin include polystyrene-based resins such as atactic polystyrene, isotactic polystyrene, syndiotactic polystyrene, AS resin, and ABS resin; polyester-based resins such as polyethylene terephthalate and polybutylene terephthalate; other polyamides such as nylon 6, 66, and 612 (polyamides other than the polyamide used in this embodiment); polyether-based resins such as polycarbonate, polyphenylene ether, polysulfone, and polyethersulfone; condensation-based resins such as polyphenylene sulfide and polyoxymethylene; acrylic-based resins such as polyacrylic acid, polyacrylic acid esters, and polymethyl methacrylate; polyolefin-based resins such as polyethylene, polypropylene, polybutene, and ethylene-propylene copolymers; halogen-containing vinyl compound-based resins such as polyvinyl chloride and polyvinylidene chloride; phenolic resins; and epoxy resins. These thermoplastic resins may be used alone or in combination of two or more.

[0067] Examples of the rubber component include natural rubber, polybutadiene, polyisoprene, polyisobutylene, neoprene, polysulfide rubber, thiokol rubber, acrylic rubber, urethane rubber, silicone rubber, epichlorohydrin rubber, styrene-butadiene block copolymer (SBR), hydrogenated styrene-butadiene block copolymer (SEB), styrene-butadiene-styrene block copolymer (SBS), hydrogenated styrene-butadiene-styrene block copolymer (SEBS), styrene-isoprene block copolymer (SIR), hydrogenated styrene-isoprene block copolymer (SEP), styrene-isoprene-styrene block copolymer (SIS), hydrogenated styrene-isoprene-styrene block copolymer (SEPS), styrene-butadiene random copolymer, hydrogenated styrene-butadiene random copolymer, and styrene-ethylene-propylene random copolymer. , styrene-ethylene-butylene random copolymer, ethylene-propylene copolymer (EPR), ethylene-(1-butene) copolymer, ethylene-(1-hexene) copolymer, ethylene-(1-octene) copolymer, ethylene-propylene-diene copolymer (EPDM), and core-shell types such as butadiene-acrylonitrile-styrene-core-shell rubber (ABS), methyl methacrylate-butadiene-styrene-core-shell rubber (MBS), methyl methacrylate-butyl acrylate-styrene-core-shell rubber (MAS), octyl acrylate-butadiene-styrene-core-shell rubber (MABS), alkyl acrylate-butadiene-acrylonitrile-styrene core-shell rubber (AABS), butadiene-styrene-core-shell rubber (SBR), and siloxane-containing core-shell rubbers such as methyl methacrylate-butyl acrylate siloxane. These rubber components may be used alone or in combination of two or more.

[0068] [Method for producing polyamide resin composition] The method for producing the polyamide resin composition of the present embodiment is not particularly limited as long as it is a method of mixing (A) polyamide, (B) brominated polystyrene, (C) flame retardant auxiliary, (D) inorganic filler, (E) a copolymer of an aromatic vinyl compound and an α,β-unsaturated dicarboxylic acid anhydride, and (F) an α,β-unsaturated dicarboxylic acid anhydride-modified polyphenylene ether.

[0069] Examples of a method for mixing (A) polyamide, (B) brominated polystyrene, (C) flame retardant auxiliary, (D) inorganic filler, (E) copolymer of aromatic vinyl compound and α,β-unsaturated dicarboxylic anhydride, and (F) α,β-unsaturated dicarboxylic anhydride-modified polyphenylene ether include a method for mixing (A) polyamide, (B) brominated polystyrene, (C) flame retardant auxiliary, and (D) inorganic filler, (E) copolymer of aromatic vinyl compound and α,β-unsaturated dicarboxylic anhydride, and (F) at least one selected from the group consisting of α,β-unsaturated dicarboxylic anhydride-modified polyphenylene ether, using a Henschel mixer or the like, and supplying the mixture to a melt kneader for kneading; An example of a method is to previously mix a copolymer of an aromatic vinyl compound and an α,β-unsaturated dicarboxylic anhydride, and (F) an α,β-unsaturated dicarboxylic anhydride-modified polyphenylene ether using a Henschel mixer or the like, feed the mixture into a melt kneader and knead it, and then optionally mix in (D) an inorganic filler from a side feeder.

[0070] The components constituting the polyamide resin composition may be supplied to the melt kneader by supplying all of the components to the same supply port at once, or by supplying each of the components from a different supply port.

[0071] The melt-kneading temperature is preferably about 1 to 100° C. higher, and more preferably about 10 to 50° C. higher, than the melting point of the (A) polyamide. The shear rate in the mixer is 100 sec -1 The average residence time during kneading is preferably about 0.5 to 5 minutes. As an apparatus for carrying out the melt kneading, a known apparatus, for example, a melt kneader such as a single screw or twin screw extruder, a Banbury mixer, or a mixing roll, is preferably used.

[0072] The blending amount of each component when producing the polyamide resin composition of the present embodiment is the same as the content of each component in the polyamide resin composition described above.

[0073] [Molded Articles of Polyamide Resin Composition] The molded article of the present embodiment is produced by using the polyamide resin composition of the present embodiment. Specifically, a predetermined molded article is obtained by molding the polyamide resin composition of the present embodiment. The method for obtaining the molded article of the present embodiment is not particularly limited, and any known molding method can be used. For example, examples of molding methods include extrusion molding, injection molding, vacuum molding, blow molding, injection compression molding, decorative molding, other material molding, gas-assisted injection molding, foam injection molding, low-pressure molding, ultra-thin-wall injection molding (ultra-high-speed injection molding), and in-mold composite molding (insert molding, outsert molding).

[0074] In addition, the molded article of the present embodiment contains the above-mentioned polyamide resin composition, and has excellent surface appearance stability of the molded article under harsh molding conditions, mechanical properties of the welds, toughness, heat resistance, and flame retardancy, and can be used in various applications. For example, it can be suitably used in the automotive field, the electrical and electronic field, the mechanical and industrial field, the office equipment field, and the aerospace field. EXAMPLES

[0075] The present invention will be described in detail below with reference to specific examples and comparative examples, but the present invention is not limited to the following examples.

[0076] First, the components of the polyamide, the methods for measuring the physical properties, and the methods for evaluating the characteristics are described below. [Measurement method] <Viscosity RV of polyamide in formic acid solution> Polyamide was dissolved in formic acid and measured according to ASTM D789.

[0077] <Polyamide end ratio> Amino terminal amount ([NH2]) In the polyamides obtained in the Examples and Comparative Examples, the amount of amino terminals bound to the polymer terminals was measured by neutralization titration as follows. 3.0 g of polyamide was dissolved in 100 mL of 90% by mass aqueous phenol solution, and the resulting solution was used for titration with 0.025 N hydrochloric acid to determine the amount of amino terminals (μ equivalents / g). The end point was determined from the indicated value of the pH meter.

[0078] Carboxyl terminal amount ([COOH]) In the polyamides obtained in the Examples and Comparative Examples, the amount of carboxyl terminals bonded to the polymer terminals was measured by neutralization titration as follows. 4.0 g of polyamide was dissolved in 50 mL of benzyl alcohol, and the resulting solution was used for titration with 0.1 N NaOH to determine the amount of carboxyl terminals (μequivalents / g). The end point was determined from the color change of the phenolphthalein indicator.

[0079] Based on the measured amounts of amino terminals ([NH2]) and carboxyl terminals ([COOH]), the total amount of active terminals ([NH2] + [COOH]) and the ratio of the amount of amino terminals to the total amount of active terminals ([NH2] / ([NH2] + [COOH])) were calculated.

[0080] <Molecular weight measurement of brominated polystyrene> GPC measurement conditions GPC equipment: HLC-8320GPC (Tosoh) Column: TSKgel GMHHR-H (7.8 mm I.D. x 30 cm) x 2 (Tosoh) Eluent: Chloroform (Fujifilm Wako Pure Chemical HPLC grade amylene additive) Detector: Differential refractometer (RI detector), polarity=(+) Flow rate: 1.0mL / min. Column temperature: 40℃ Sample concentration: 2mg / mL Sample injection volume: 100 μL Sample pretreatment: The sample was weighed, a specified amount of eluent was added, and the sample was left to stand overnight at room temperature, and then heated and dissolved at 50°C for 1 hour. After that, the sample was gently shaken and filtered through a 0.45 μm PTFE cartridge filter. In addition, no insoluble matter was found in any of the samples when the sample solution was visually inspected. Calibration curve: A third-order approximation curve using standard polystyrene (PS) (manufactured by Tosoh Corporation) was used. Therefore, the obtained value is the molecular weight converted into PS.

[0081] <Extrusion property> The method for producing the polyamide resin composition was to use a twin-screw extruder (manufactured by Coperion (Germany), ZSK-26MC) with an upstream supply port on the first barrel from the upstream side of the extruder, a downstream supply port on the eighth barrel, and a vacuum devolatilization port on the tenth barrel, with L / D (length of the cylinder of the extruder / cylinder diameter of the extruder) = 48 (number of barrels: 12), and the temperature from the upstream supply port to the die was set at the melting point of the polyamide + 20 ° C., the screw rotation speed was 300 rpm, and the discharge rate was 25 kg / hour. (A) polyamide resin, (B) brominated polystyrene, (C) flame retardant auxiliary, (E) copolymer of aromatic vinyl compound and α, β unsaturated dicarboxylic anhydride (F) α, β unsaturated dicarboxylic anhydride modified polyphenylene ether were supplied from the upstream supply port, and (D) inorganic filler (glass fiber) was supplied from the downstream supply port, and the mixture was melt-kneaded under reduced pressure from the vacuum devolatilization port to produce pellets of the polyamide resin composition.

[0082] When preparing the composition, the composition was taken out in strand form and the surface of the strand was visually observed. Those that were smooth and free of fuzz and did not experience strand breakage for 15 minutes or more were rated as (◯), those that were slightly fuzzed but did not experience strand breakage for 15 minutes or more were rated as (△), and those that were fuzzed and experienced strand breakage within 15 minutes were rated as (×).

[0083] <Number of sunspots> 1000 g of pellets were collected, and the number of black spots on the pellet surface was counted by visual observation. The number of black spots is preferably 200 or less, more preferably 100 or less, and further preferably 50 or less.

[0084] <Heating weight reduction rate> The weight loss of the sample when it was held at 310°C for 30 minutes in a nitrogen stream using Thermo plus EVO2 TG-DTA8122 (manufactured by Rigaku Corporation) was expressed as a percentage. The smaller the weight loss, the better the success rate. There is little gas generation during molding and also little metal corrosion.

[0085] <Tensile strength> The injection molding machine used was NEXIV manufactured by Nissei Plastic Industrial Co., Ltd. The cylinder temperature was set to the melting point of the polyamide + 20°C, the mold temperature was set to the glass transition temperature of the polyamide + 20°C, and molding was performed using each polyamide composition under injection molding conditions of 10 seconds injection and 10 seconds cooling to obtain molded products (ISO test pieces). The tensile strength of the ISO test pieces was measured at a pulling speed of 5 mm / min according to ISO 527. The measured value was the average value of n=6.

[0086] <Tensile strength after aging> (Tensile strength and heat aging resistance) Using the above molded products (ISO test pieces), a tensile test was performed at a tensile speed of 5 mm / min in accordance with ISO527, and the initial tensile strength (MPa) was measured (S0). Next, each multipurpose test piece (A type) was placed in an oven in accordance with ISO188, heated at 150°C for 1000 hours, and aged. The molded products (ISO test pieces) were then removed from the oven and cooled at 23°C for 24 hours. Next, a tensile test was performed on the molded products (ISO test pieces) after aging at a tensile speed of 5 mm / min in accordance with ISO527, and the tensile strength (MPa) after the heat aging test was measured (S1). Next, the tensile strength retention rate (%) was calculated using the formula shown below. "Tensile strength retention rate (%)" = S1 / S0 x 100 The higher the tensile strength retention rate, the more excellent the heat aging resistance properties.

[0087] <Weld strength> A mold was attached to an injection molding machine (NEXIV manufactured by Nissei Plastics Industries) in which molten resin flows from both ends of the length direction of a shape of 127 mm in length, 12.7 mm in width, and 1.6 mm in thickness, forming a weld in the center in the length direction. The cylinder temperature was set to the melting point of the polyamide + 20°C, and the mold temperature was set to the glass transition temperature of the polyamide + 20°C, and molding was performed to obtain a test piece. A tensile test was performed on this molded test piece according to the method conforming to ISO 527, except that the chuck distance was 50 mm and the tensile speed was 50 mm / min, and the tensile strength was obtained. The measured value was the average value of n = 6.

[0088] <Right-angle bending deflection amount> Molding was performed using an injection molding machine [NEXIV manufactured by Nissei Plastics], with a cylinder temperature of the melting point of the polyamide + 20°C and a flat mold of 60mm x 60mm x 1mmt (mold temperature = glass transition temperature of polyamide + 20°C). A rectangular test piece of 13mm x 60mm x 1mmt was cut out from this flat plate at a point 20mm away from the gate position in the flow direction in the direction perpendicular to the flow, and a bending test was performed using a method conforming to ASTM D 790. The displacement (mm) at which bending failure occurred was recorded as the bending deflection.

[0089] <Charpy impact test> The pellets of each polyamide resin composition were molded into a multipurpose test piece type A of ISO 3167 using an injection molding machine [NEX IV manufactured by Nissei Plastics Co., Ltd.] with the injection + pressure holding time set to 25 seconds, cooling time set to 15 seconds, mold temperature set to 80 ° C, and molten resin temperature set to 270 ° C. Next, the multipurpose test piece type A of the molded piece was processed into a notched test piece according to ISO 2818. The Charpy impact strength of the obtained notched test piece was measured according to JIS K7111 (ISO 179). The larger the value, the better the mechanical strength was evaluated to be.

[0090] <Liquidity> The polyamide resin composition was injection molded under the following conditions, and the flow length (spiral flow value) was measured by measuring the length of the molded piece. Before measuring the spiral flow value, the pellets were dried at 80°C for 48 hours, and the moisture content of the pellets was confirmed to be less than 300 ppm, and then the measurement was performed under the following conditions.

[0091] Injection molding machine: NEXIII manufactured by Nissei Plastics Co., Ltd. Measurement mold: Spiral mold with inner groove width (cavity) of 10 mm and thickness of 1 mm Mold temperature: 80℃ Set temperature: Melting point of polyamide (A) + 20℃ Injection pressure: 70MPa (injection speed is controlled by injection pressure at maximum setting) Ejection time: 10 seconds Cooling time: 10 seconds

[0092] <Flame retardancy> Measurement was performed using the method of UL94 (standard established by Underwriters Laboratories Inc., USA). The test pieces (length 127 mm, width 12.7 mm, thickness 0.3 mm) were prepared by attaching a UL test piece mold (mold temperature = glass transition temperature of polyamide + 20 ° C.) to an injection molding machine (PS40E manufactured by Nissei Kogyo Co., Ltd.) and molding the polyamide resin composition at a cylinder temperature of the melting point of polyamide + 20 ° C. The injection pressure was the full filling pressure + 2% when molding the UL test piece. The flame retardant grade was in accordance with the UL94 standard (vertical flame test). If the product did not meet any of the UL94 grades, it was deemed "non-compliant."

[0093] To obtain a V-0 rating under UL94, the total flaming burn time must be 50 seconds or less, the maximum burning time must be 10 seconds or less, the cotton placed directly under the test specimen must not ignite, and the flames must not reach the clamp. As an index for evaluation within the V-0 grade, the shorter the total flaming combustion time (t1 + t2) after two flame applications (total of 10 applications) for each of the five test specimens, and the fewer the number of drips, the less the risk of the cotton placed directly below the test specimen igniting and the risk of the flame reaching the clamp, indicating better flame retardancy.

[0094] [Ingredients for each sample] (A) Production of polyamide resin Using a 40 L autoclave, polyamide 66 with the terminal group concentrations shown below in (A-1), (A-2), and (A-3) were polymerized. The terminal groups were adjusted by the type and amount of terminal group regulator added, and the melt-polymerized polyamide was taken out of the lower nozzle in the form of strands to obtain polyamide pellets.

[0095] (A-1) Polyamide 66: Formic acid relative viscosity (RV) = 46, terminal amino group ratio = 46.0 milliequivalents / kg (37%), terminal carboxyl group = 78.0 milliequivalents / kg (63%), melting point = 265°C (A-2) Polyamide 66: Formic acid relative viscosity (RV) = 41, terminal amino group ratio = 75.5 milliequivalents / kg (59%), terminal carboxyl group = 52.1 milliequivalents / kg (41%), melting point = 265°C (A-3) Polyamide 66: Formic acid relative viscosity (RV) = 36, terminal amino group ratio = 38 milliequivalents / kg (30%), terminal carboxyl group = 90 milliequivalents / kg (70%), melting point = 265°C (A-4) Polyamide 6T / 66: Aromatic polyamide (PA6T / 66=65 / 35) made of hexamethylenediamine, terephthalic acid and adipic acid, melting point: 325°C

[0096] (a-1) Method for producing polyamide 66 The polymerization reaction of polyamide 66 was carried out by the "melt polymerization method" as follows. 1500 g of an equimolar salt of adipic acid and hexamethylenediamine, and 0.1 mol % excess adipic acid relative to the total equimolar salt components were dissolved in 1500 g of distilled water to prepare a 50 mass % equimolar homogeneous aqueous solution of the raw material monomers. While stirring at a temperature of 110 to 150°C, the solution was concentrated by gradually releasing steam until the solution concentration reached 70% by mass. The internal temperature was then raised to 220°C. At this time, the autoclave was pressurized to 1.8 MPa. The reaction was continued for 1 hour while gradually releasing steam to maintain the pressure at 1.8 MPa until the internal temperature reached 245°C. Next, the pressure was reduced over 30 minutes, and then the inside of the autoclave was kept under a reduced pressure of 650 torr for 10 minutes using a vacuum device, at which time the final internal temperature of the polymerization was 265°C. Thereafter, the mixture was pressurized with nitrogen and formed into a strand from the lower spinneret (nozzle), water-cooled, cut, and discharged in the form of pellets. The pellets were then dried at 100°C in a nitrogen atmosphere for 12 hours to obtain polyamide 66.

[0097] (a-2) Production method of polyamide 66 Polymerization was carried out in the same manner as in (a-1) polyamide 66 above, except that no excess adipic acid was added and 0.3 mol % excess hexamethylenediamine was dissolved relative to the total equimolar salt components, to obtain (a-2) polyamide 66 in the form of pellets.

[0098] (a-3) Production method of polyamide 66 Except for dissolving adipic acid in an amount of 0.5 mol % in excess relative to the total equimolar salt components, polymerization was carried out in the same manner as in (a-1) polyamide 66, to obtain (a-3) polyamide 66 in the form of pellets.

[0099] (B) Brominated polystyrene (B-1) Brominated polystyrene (manufactured by ALBEMARLECORPORATION, product name SAYTEX (registered trademark) HP-3010PST (Mw = 3557, Mn = 2978, Mw / Mn = 1.16)) Bromine content: 67% (B-2) Brominated polystyrene (manufactured by ALBEMARLE CORPORATION, product name SAYTEX (registered trademark) HP-7010G (Mw = 147109, Mn = 55982, Mw / Mn = 2.63) Bromine content 67%

[0100] (C) Flame retardant assistant: Antimony trioxide (manufactured by Campine, product name: Antimony trioxide)

[0101] (D) Inorganic filler: Glass fiber (GF) (manufactured by Megashi Group Co., Ltd., product name ECS10-03-568H, average fiber diameter 10 μmφ, cut length 3 mm)

[0102] (E) Copolymer of aromatic vinyl compound and α,β-unsaturated dicarboxylic acid anhydride (E-1) Copolymer of styrene and maleic anhydride (Polyscope, product name SZ15170, Mw=170000, copolymer of 85% by mass of styrene and 15% by mass of maleic anhydride) (E-2) Styrene and maleic anhydride copolymer (manufactured by Polyscope, trade name XIBOND220, Mw=15000, copolymer of 89% by mass of styrene and 11% by mass of maleic anhydride) (E-3) Styrene and maleic anhydride copolymer (Polyscope, trade name) XIBOND280, Mw=5000, copolymer of 57% styrene and 43% maleic anhydride)

[0103] (F) Polyphenylene ether modified with α,β-unsaturated dicarboxylic acid anhydride (F-1) Synthesis of modified polyphenylene ether with 0.5% maleic anhydride addition rate 100 parts by mass of poly(2,6-dimethyl-1,4-phenylene ether) (hereinafter sometimes abbreviated as "polyphenylene ether") with a reduced viscosity (0.5 g / dL chloroform solution, measured at 30 ° C) of 0.52 obtained by oxidative polymerization of 2,6-dimethylphenol, 0.1 parts by mass of radical initiator, and 1.5 parts by mass of maleic anhydride as a compatibilizer were used. The mixture was melt-kneaded under the conditions of a cylinder set temperature of 320 ° C, a screw rotation of 300 rpm, and a discharge rate of 20.15 kg / hr, and taken out in the form of a strand, and cooled in a strand bath. The mixture was then granulated with a cutter to obtain pellets of maleic anhydride-modified polyphenylene ether. The addition rate of maleic anhydride was 0.5%. (F-2) Synthesis of modified polyphenylene ether with 0.1% maleic anhydride addition rate A pellet of maleic anhydride-modified polyphenylene ether was obtained by the same production method as above (F-1), except that the amount of maleic anhydride was 0.3 parts by mass. The maleic anhydride addition rate was 0.1%.

[0104] (G) Rubber component (G-1) Maleic anhydride modified hydrogenated styrene-butadiene copolymer, manufactured by Asahi Kasei, product name "Tuftec M1943"

[0105] (H) Alkaline earth metal compounds: Calcium oxide (Fujifilm Wako Pure Chemical Industries, Ltd.)

[0106] (I) Antioxidant: BASF hindered phenol antioxidant, product name "Irganox 1098"

[0107] <Production of polyamide resin composition> [Examples 1 to 13 and Comparative Examples 1 to 8] Except for blending the raw materials so as to obtain the compositions shown in Tables 1 and 2, each polyamide resin composition was produced by the following method. The method for producing the polyamide resin composition was to use a twin-screw extruder (manufactured by Coperion (Germany), ZSK-26MC) with an upstream supply port in the first barrel from the upstream side of the extruder, a downstream supply port in the eighth barrel, and a vacuum devolatilization port in the tenth barrel, with L / D (length of the cylinder of the extruder / cylinder diameter of the extruder) = 48 (number of barrels: 12), set at 280 ° C. from the upstream supply port to the die, screw rotation speed 300 rpm, and discharge rate 25 kg / hour. (A) polyamide resin, (B) brominated polystyrene, (C) flame retardant auxiliary, (E) copolymer of aromatic vinyl compound and α,β-unsaturated dicarboxylic anhydride, (F) α,β-unsaturated dicarboxylic anhydride-modified polyphenylene ether, and (D) inorganic filler (glass fiber) were supplied from the downstream supply port, and melt-kneaded under reduced pressure from the vacuum devolatilization port to produce pellets of the polyamide resin composition. Specifically, the polymer was discharged in the form of strands from the nozzle at the tip of the extruder, and after the resin temperature was measured, the polymer was cooled with water and cut to obtain pellets of the polyamide resin composition.

[0108] The obtained polyamide resin composition was used to produce a molded product by the above-mentioned method, and the above-mentioned extrudability, black spots, heat weight loss rate, tensile strength, tensile strength after aging, weld strength, right-angle bending deflection amount, Charpy impact test, flame retardancy, and flowability were evaluated. The evaluation results are shown in Table 1.

[0109] [Table 1]

[0110] As shown in Table 1, in Examples 1 to 13 which contained components (A) to (F) and fell within the prescribed ranges, the flowability, flame retardancy, tensile properties, and weld strength were all well-balanced and excellent. On the other hand, as shown in Table 2, in Comparative Examples 1 to 8, when the proportions of components (A) to (F) did not satisfy the prescribed ranges, the extrudability, fluidity, flame retardancy, thermal decomposition resistance, weld strength, and toughness were all not good. In particular, when Example 1 is compared with Comparative Example 7, it is found that Example 1 satisfies the prescribed range of brominated polystyrene (B), and is therefore excellent in fluidity, flame retardancy, and toughness. Comparing Example 1 with Comparative Examples 1 and 6, it is clear that Example 1 is excellent in extrudability, fluidity, flame retardancy, and toughness because (E) and (F) satisfy the prescribed ranges. [Industrial Applicability]

[0111] According to the present invention, it is possible to provide a polyamide resin composition which is excellent in extrusion processability, molding processability, mechanical properties, and flame retardancy, as well as in flow properties during molding, toughness, and drip suppression during a combustion test. In particular, the polyamide resin composition of the present invention is thin-walled yet excellent in flame retardancy, weld strength, and toughness, and is more suitably used as a material for electrical and electronic parts having a dense structure.

Claims

1. (A) 20 to 70 mass% of polyamide, (B) 10 to 35 mass% of brominated polystyrene, (C) 1 to 15 mass% of a flame retardant aid, (D) 10 to 60 mass% of an inorganic filler, (E) 0.1 to 1.5 mass% of a copolymer of an aromatic vinyl compound and an α,β-unsaturated dicarboxylic acid anhydride, and (F) 1 to 5 mass% of a polyphenylene ether modified with an α,β-unsaturated dicarboxylic acid anhydride, A polyamide resin composition characterized in that the brominated polystyrene (B) has a bromine content of 64 to 71 mass % and a weight average molecular weight of 1,000 to 10,000.

2. The polyamide resin composition according to claim 1, characterized in that the α,β-unsaturated dicarboxylic acid anhydride component contained in the copolymer of an aromatic vinyl compound and an α,β-unsaturated dicarboxylic acid anhydride (E) is 1 to 40 mass% based on the total amount of the components (E).

3. 3. The polyamide resin composition according to claim 1, wherein the weight average molecular weight of the copolymer (E) of an aromatic vinyl compound and an α,β-unsaturated dicarboxylic acid anhydride is 10,000 to 250,000.

4. The polyamide resin composition according to claim 1 or 2, characterized in that the α,β-unsaturated dicarboxylic anhydride component contained in the (F) α,β-unsaturated dicarboxylic anhydride modified polyphenylene ether is 0.2 to 1.0 mass% based on the total amount of the (F).

5. The polyamide resin composition according to claim 3, characterized in that the α,β-unsaturated dicarboxylic anhydride component contained in the (F) α,β-unsaturated dicarboxylic anhydride modified polyphenylene ether is 0.2 to 1.0 mass% based on the total amount of the (F).

6. 3. The polyamide resin composition according to claim 1, wherein the melting point of the polyamide (A) is 200°C or higher and 270°C or lower.

7. 4. The polyamide resin composition according to claim 3, wherein the melting point of the polyamide (A) is 200°C or higher and 270°C or lower.

8. 5. The polyamide resin composition according to claim 4, wherein the melting point of the polyamide (A) is 200°C or higher and 270°C or lower.

9. A molded article, characterized by using the polyamide resin composition according to claim 1 or 2.