Polyamide resin composition and molded article

Abstract

The purpose of the present invention is to provide: a polyamide resin composition excellent in mechanical properties when formed into a molded article, in particular, excellent in mechanical strength under a heat condition and a moist heat condition, impact resistance under a low temperature condition, tracking resistance, and insulation breakdown resistance under a high temperature condition; and a molded article thereof. The polyamide resin composition according to the present invention comprises: (A) a crystalline aliphatic polyamide; and (B) a crystalline semi-aromatic polyamide containing a diamine unit and a dicarboxylic acid unit derived from a dicarboxylic acid or a salt thereof or a mixture thereof. The dicarboxylic acid unit of the component (B) includes 90-100 mol% of a terephthalic acid unit, 0-10 mol% of one or more other aromatic dicarboxylic acid units, and 0-2 mol% of an aliphatic dicarboxylic acid unit. The ratio "number of carbon C / number of nitrogen N" in the component (B) is greater than 6.00 and less than 7.00. The content of the component (B) is 10.0-40.0 mass% with respect to 100 mass% of the total mass of all the polyamides in the polyamide resin composition.

Description

Polyamide resin composition and molded article

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

[0002] Polyamide resins have excellent strength, heat resistance, and chemical resistance, as well as a high specific gravity. Because of their lower specific gravity than metals, they have traditionally been used as a metal substitute for automotive mechanical components. In recent years, with the shift to electric vehicles and electric vehicles, electrical and electronic components have become lighter, more compact, and have larger capacities. This has led to increased demand for improved physical properties for resin molded products, which form part of these components. Because of the need for lighter weight and more space-saving designs, the thickness of resin molded products has become thinner than before, necessitating improvements in the mechanical properties of the resin itself. Furthermore, because the increased capacity promotes heat generation and creates high-temperature environments, resin molded products are required to have electrical properties at high temperatures, particularly tracking resistance and dielectric breakdown resistance.

[0003] For example, Patent Documents 1 and 2 disclose polyamide resin compositions having excellent tracking resistance, which contain a semi-aromatic polyamide having an aromatic dicarboxylic acid unit, a flame retardant, and a reinforcing material.

[0004] JP 2018-35211 A JP 2020-503408 A

[0005] Furthermore, when automobiles are driven in cold regions, not only high-temperature properties but also low-temperature properties are required to be at a higher level. In particular, for component applications such as automobile parts and solar power generation modules that are expected to be used in cold regions, impact resistance under low-temperature conditions needs to be improved compared to aliphatic polyamides such as polyamide 66 and aromatic polyamides such as 6T / 6I. Therefore, polyamide resin materials with little change in physical properties under all environments are required. However, in the polyamide resin composition described in Patent Document 1 and the like, although the use of crystalline semi-aromatic polyamide improves mechanical properties and tracking resistance at high temperatures, the rigid structure of the crystalline semi-aromatic polyamide raises concerns about low-temperature properties, particularly impact resistance.

[0006] The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a polyamide resin composition which, when formed into a molded article, has excellent mechanical properties, in particular mechanical strength under hot and wet heat conditions, impact resistance and tracking resistance under low-temperature conditions, and dielectric breakdown resistance under high-temperature conditions, and a molded article containing the polyamide resin composition.

[0007] That is, the present invention is as follows: [1] A polyamide resin composition containing (A) a crystalline aliphatic polyamide and (B) a crystalline semi-aromatic polyamide containing diamine units and dicarboxylic acid units derived from a dicarboxylic acid or a salt thereof, or a mixture thereof, wherein the dicarboxylic acid units contained in the (B) crystalline semi-aromatic polyamide consist of 90 to 100 mol % of terephthalic acid units, 0 to 10 mol % of one or more aromatic dicarboxylic acid units other than terephthalic acid units, and 0 to 2 mol % of aliphatic dicarboxylic acid units, relative to the total number of moles of the dicarboxylic acid units, the ratio of the number of carbon atoms C to the number of nitrogen atoms N (C / N ratio) in the (B) crystalline semi-aromatic polyamide is more than 6.00 and less than 7.00, and the content of the (B) crystalline semi-aromatic polyamide is 10.0 to 40.0 mass %, relative to the total mass of all polyamides in the polyamide resin composition (100 mass %). [2] The polyamide resin composition according to [1], wherein the melting point TmA2 of the crystalline aliphatic polyamide (A) is 240°C or higher and 270°C or lower. [3] The polyamide resin composition according to [1] or [2], wherein the crystalline aliphatic polyamide (A) is polyamide 66 (PA66). [4] The polyamide resin composition according to any one of [1] to [3], wherein the diamine units of the crystalline semi-aromatic polyamide (B) are diamine units having a linear or branched saturated aliphatic group having from 4 to 6 carbon atoms. [5] The polyamide resin composition according to any one of [1] to [4], wherein the crystalline semi-aromatic polyamide (B) contains 100 mol% of terephthalic acid units relative to the total number of moles of the dicarboxylic acid units. [6] The polyamide resin composition according to any one of [1] to [5], wherein the melting point TmB2 of the crystalline semi-aromatic polyamide (B) is 330°C or higher and 360°C or lower. [7] The polyamide resin composition according to any one of [1] to [6], containing 5 to 250 parts by mass of (C) inorganic filler per 100 parts by mass of the total mass of the (A) crystalline aliphatic polyamide and the (B) crystalline semi-aromatic polyamide.[8] The polyamide resin composition according to any one of [1] to [7], wherein the tan δ peak temperature of the (B) crystalline semi-aromatic polyamide is 150°C or higher. [9] The polyamide resin composition according to any one of [1] to [8], comprising (D) at least one selected from the group consisting of metal phosphites and metal hypophosphites.

[10] The polyamide resin composition according to any one of [1] to [9], wherein the tan δ peak temperature of the polyamide resin composition is 90°C or higher.

[11] The polyamide resin composition according to any one of [1] to

[10] , wherein the weight average molecular weight Mw of the polyamide resin composition is 20,000 or higher and 40,000 or lower.

[12] The polyamide resin composition according to any one of [1] to

[11] , wherein the molecular weight distribution Mw / Mn (Mw is the weight average molecular weight, Mn is the number average molecular weight) of the polyamide resin composition is 2.4 or lower.

[13] The polyamide resin composition according to any one of [1] to

[12] , wherein the area ΔHM1 of a melting peak at above 150°C of the polyamide resin composition is 95% or more relative to the total area ΔHM of all melting peaks in the polyamide resin composition.

[14] The polyamide resin composition according to any one of [1] to

[13] , wherein the total polyamide content is 97% by mass or more relative to 100% by mass of all resin components in the polyamide resin composition.

[15] The polyamide resin composition according to any one of [1] to

[14] , wherein the ratio (E'-2 / E'-1) of the storage modulus E'-2 at 120°C to the storage modulus E'-1 at 23°C of the polyamide resin composition is 0.40 or more.

[16] A molded article comprising the polyamide resin composition according to any one of [1] to

[15] .

[0008] According to the present invention, it is possible to provide a polyamide resin composition which, when molded into a molded article, has excellent mechanical properties, in particular mechanical strength under hot and wet heat conditions, impact resistance and tracking resistance under low-temperature conditions, and dielectric breakdown resistance under high-temperature conditions, and a molded article containing the polyamide resin composition.

[0009] Hereinafter, an embodiment of the present invention (hereinafter abbreviated as "present embodiment") will be described in detail. Note that the present invention is not limited to the following embodiment, and various modifications can be made within the scope of the gist of the present invention.

[0010] In this specification, the term "polyamide" refers to a polymer having an amide (-NHCO-) ​​group in the main chain.

[0011] <Polyamide Resin Composition> The polyamide resin composition of the present embodiment is excellent in mechanical properties when formed into a molded article, particularly mechanical strength at high temperatures and under wet heat conditions, impact resistance and tracking resistance under low-temperature conditions, and dielectric breakdown resistance under high-temperature conditions.

[0012] The polyamide resin composition of this embodiment contains (A) a crystalline aliphatic polyamide, (B) a crystalline semi-aromatic polyamide, and optionally other components described below, and the content of the (B) crystalline semi-aromatic polyamide is 10.0 to 40.0 mass% relative to the total mass of all polyamides in the polyamide resin composition (100 mass%), preferably 12.5 to 37.5 mass%, more preferably 15.0 to 35.0 mass%, even more preferably 17.5 to 32.5 mass%, even more preferably 20.0 to 30.0 mass%, and particularly preferably 25.0 to 30.0 mass%. By setting the content of the (B) crystalline semi-aromatic polyamide within the above range, a polyamide resin composition can be obtained that is excellent in mechanical properties, particularly mechanical strength under hot and wet heat conditions, impact resistance and tracking resistance under low-temperature conditions, and dielectric breakdown resistance under high-temperature conditions.

[0013] Hereinafter, each of the constituent components contained in the polyamide resin composition of the present embodiment will be described in detail.

[0014] <(A) Crystalline Aliphatic Polyamide> In this embodiment, the (A) crystalline aliphatic polyamide refers to an aliphatic polyamide having a crystallization enthalpy ΔH of 5 J / g or more. The crystallization enthalpy ΔH can be measured using a measuring device such as a Diamond-DSC manufactured by Perkin-Elmer.

[0015] Specific examples of the crystalline aliphatic polyamide (A) include, but are not limited to, (a) polyamides obtained by ring-opening polymerization of lactams, (b) polyamides obtained by self-condensation of ω-aminocarboxylic acids, (c) polyamides obtained by condensing diamines and dicarboxylic acids, and copolymers thereof. The crystalline aliphatic polyamide (A) may be used alone or as a mixture of two or more types.

[0016] The total proportion of lactam unit, aminocarboxylic acid unit, diamine unit and dicarboxylic acid unit is preferably 80 mol% or more and 100 mol% or less, more preferably 90 mol% or more and 100 mol% or less, and even more preferably 100 mol% with respect to the total amount of all the constituent units of (A) crystalline aliphatic polyamide.In this specification, the proportion of the predetermined monomer unit that constitutes (A) crystalline aliphatic polyamide can be measured by nuclear magnetic resonance spectroscopy (NMR) etc.

[0017] Examples of lactams that can be used as raw materials for (a) polyamide include, but are not limited to, pyrrolidone, caprolactam, undecalactam, and dodecalactam. (a) Polyamide may be a condensation product of two or more lactams.

[0018] The ω-aminocarboxylic acid used as a raw material for the (b) polyamide is not limited to the following, but examples thereof include ω-amino fatty acids, which are ring-opened compounds of the above-mentioned lactams with water. The (b) polyamide may also be a condensation product of two or more ω-aminocarboxylic acids.

[0019] (c) Examples of diamines (monomers) that are raw materials for polyamides include, but are not limited to, linear saturated aliphatic diamines having 2 to 20 carbon atoms, such as ethylenediamine, propylenediamine, tetramethylenediamine, pentamethylenediamine, hexamethylenediamine, heptamethylenediamine, octamethylenediamine, nonamethylenediamine, decamethylenediamine, undecamethylenediamine, dodecamethylenediamine, and tridecamethylenediamine.

[0020] Furthermore, (c) diamines (monomers) serving as raw materials for polyamides include, but are not limited to, diamines constituting diamine units having a substituent branched from the main chain, such as branched saturated aliphatic diamines having 3 to 20 carbon atoms, such as 2-methylpentamethylenediamine (also referred to as 2-methyl-1,5-diaminopentane), 2,2,4-trimethylhexamethylenediamine, 2,4,4-trimethylhexamethylenediamine, 2-methyl-1,8-octanediamine (also referred to as 2-methyloctamethylenediamine), and 2,4-dimethyloctamethylenediamine. Among these, 2-methylpentamethylenediamine or 2-methyl-1,8-octanediamine is preferred, and 2-methylpentamethylenediamine is more preferred. By including such aliphatic diamines, polyamide resin compositions tend to have superior heat resistance, rigidity, and the like.

[0021] The diamine unit preferably has a carbon number of 4 or more and 12 or less, more preferably 4 or more and 10 or less. When the carbon number is equal to or more than the lower limit, the polyamide tends to have better heat resistance, while when the carbon number is equal to or less than the upper limit, the polyamide tends to have better crystallinity and releasability.

[0022] The crystalline aliphatic polyamide (A) may further contain a trivalent or higher polyvalent aliphatic amine such as bishexamethylenetriamine, if necessary. The trivalent or higher polyvalent aliphatic amine may be used alone or in combination of two or more.

[0023] (c) Dicarboxylic acids (monomers) used as raw materials for polyamides include, but are not limited to, aliphatic dicarboxylic acids such as succinic acid, adipic acid, pimelic acid, sebacic acid, dodecanedioic acid, and tetradecanedioic acid; aromatic dicarboxylic acids such as isophthalic acid, terephthalic acid, naphthalenedicarboxylic acid, 2-chloroterephthalic acid, 2-methylterephthalic acid, 5-methylisophthalic acid, and 5-sodium sulfoisophthalic acid; and alicyclic dicarboxylic acids such as cyclohexanedicarboxylic acid. (A) Crystalline aliphatic polyamides may further contain units derived from trivalent or higher polycarboxylic acids such as trimellitic acid, trimesic acid, and pyromellitic acid, as necessary. The trivalent or higher polycarboxylic acids may be used alone or in combination of two or more.

[0024] The diamine and dicarboxylic acid as the monomers may each be used alone or in combination of two or more.

[0025] In (A) crystalline aliphatic polyamide, the dicarboxylic acid constituting the dicarboxylic acid unit is not limited to the compounds described above as dicarboxylic acids, but may be a compound equivalent to the dicarboxylic acid. Here, "a compound equivalent to a dicarboxylic acid" refers to a compound that can have the same dicarboxylic acid structure as the dicarboxylic acid structure derived from the dicarboxylic acid. Such compounds include, but are not limited to, anhydrides and halides of dicarboxylic acids.

[0026] Specific examples of the crystalline aliphatic polyamide (A) used in the polyamide resin composition of the present embodiment include, but are not limited to, polyamide 4 (poly-α-pyrrolidone), polyamide 6 (polycaproamide), polyamide 11 (polyundecaneamide), polyamide 12 (polydodecanamide), polyamide 46 (polytetramethylene adipamide), polyamide 56 (polypentamethylene adipamide), polyamide 66 (polyhexamethylene adipamide), polyamide 610 (polyhexamethylene sebacamide), polyamide 612 (polyhexamethylene dodecamide), polyamide 4T (polytetramethylene terephthalamide), polyamide 6T (polyhexamethylene terephthalamide), and polyamide 9T (polynonamethylene terephthalamide), as well as copolymer polyamides containing these as constituent components. Among these, polyamide 6, polyamide 46, polyamide 66, or polyamide 610 is preferred, and polyamide 6, polyamide 66, or polyamide 610 is more preferred. Polyamide 66 is considered to be a suitable material for automotive parts because of its excellent heat resistance, moldability, and toughness. Long-chain aliphatic polyamides such as polyamide 610 are also preferred because of their excellent chemical resistance.

[0027] In the polyamide resin composition of this embodiment, the content of the crystalline aliphatic polyamide (A) relative to the total mass of all polyamides in the polyamide resin composition (100 mass%) can be, for example, 60.0 mass% to 90.0 mass%, preferably 62.5 mass% to 87.5 mass%, more preferably 65.0 mass% to 85.0 mass%, even more preferably 67.5 mass% to 82.5 mass%, even more preferably 70.0 mass% to 80.0 mass%, and particularly preferably 75.0 mass% to 80.0 mass%. By setting the content of the crystalline aliphatic polyamide (A) within the above range, a polyamide resin composition tends to be obtained which is superior in mechanical properties when molded into a molded product, particularly mechanical strength under hot and wet heat conditions, impact resistance under low-temperature conditions, and dielectric breakdown resistance. Furthermore, when the polyamide resin composition further contains a component typified by (C) an inorganic filler, which will be described later, the polyamide resin composition tends to have an excellent surface appearance when molded into an article.

[0028] <(B) Crystalline Semi-Aromatic Polyamide> In this embodiment, the crystalline semi-aromatic polyamide (B) refers to a semi-aromatic polyamide having a crystallization enthalpy ΔH of 5 J / g or more. The crystallization enthalpy ΔH can be measured using a measuring device such as a Diamond-DSC manufactured by Perkin-Elmer.

[0029] The semi-aromatic polyamide is a polyamide containing aromatic structural units, and the content of aromatic structural units in all structural units of the crystalline semi-aromatic polyamide (B) is preferably 70 to 100 mol %, more preferably 80 to 100 mol %, and even more preferably 90 to 100 mol %. Here, "aromatic structural units" refers to aromatic diamine units and aromatic dicarboxylic acid units.

[0030] Specific examples of (B) crystalline semi-aromatic polyamides include polyamides containing (Ba) dicarboxylic acid units and (B-b) diamine units derived from dicarboxylic acids, their salts, or mixtures thereof, as well as copolymers thereof. The (B) crystalline semi-aromatic polyamides may also contain other structural units such as lactam units and aminocarboxylic acid units. The (B) crystalline semi-aromatic polyamides may be used alone or as a mixture of two or more. The total amount of the (Ba) dicarboxylic acid units and (B-b) diamine units is preferably 75 mol% to 100 mol%, more preferably 90 mol% to 100 mol%, and even more preferably 100 mol%, based on the total amount of all structural units of the (B) crystalline semi-aromatic polyamide. In this specification, the proportion of a specific monomer unit constituting the (B) crystalline semi-aromatic polyamide can be measured by NMR or the like.

[0031] [(Ba-a) Dicarboxylic Acid Unit] The (Ba-a) dicarboxylic acid unit is a dicarboxylic acid unit derived from a dicarboxylic acid, a salt thereof, or a mixture thereof. The salt of the dicarboxylic acid is not particularly limited, and examples thereof include salts with alkali metals, alkaline earth metals, ammonia, organic amine compounds, etc.

[0032] The (B-a) dicarboxylic acid units are preferably 90 to 100 mol % terephthalic acid units, 0 to 10 mol % one or more aromatic dicarboxylic acid units other than terephthalic acid units, and 0 to 2 mol % aliphatic dicarboxylic acid units, relative to the total moles of the (B-a) dicarboxylic acid units, 95 to 100 mol % terephthalic acid units, 0 to 5 mol % one or more other aromatic dicarboxylic acid units, and 0 to 2 mol % aliphatic dicarboxylic acid units, and more preferably 100 mol % terephthalic acid units. When the content of each dicarboxylic acid unit relative to the total moles of the (B-a) dicarboxylic acid units is at least the above lower limit, the polyamide resin composition is excellent in mechanical properties, particularly mechanical strength under hot and wet heat conditions, impact resistance under low-temperature conditions, and dielectric breakdown resistance. The dicarboxylic acid unit (B-a) may contain, for example, an alicyclic dicarboxylic acid unit in addition to the terephthalic acid unit, other aromatic dicarboxylic acid unit, and aliphatic dicarboxylic acid unit. Furthermore, polyamide resin compositions containing a component typified by the inorganic filler (C) described below tend to have excellent surface appearance when molded. The dicarboxylic acid unit (B-a) may be a single type or a combination of two or more types.

[0033] (Other Aromatic Dicarboxylic Acid Units) Examples of aromatic dicarboxylic acids constituting other aromatic dicarboxylic acid units other than terephthalic acid units include, but are not limited to, dicarboxylic acids having a phenyl group or a naphthyl group. The aromatic group of the aromatic dicarboxylic acid may be unsubstituted or may have a substituent. Examples of the substituent include, but are not limited to, alkyl groups having 1 to 4 carbon atoms, aryl groups having 6 to 10 carbon atoms, arylalkyl groups having 7 to 10 carbon atoms, halogen groups such as chloro groups and bromo groups, silyl groups having 1 to 6 carbon atoms, sulfonic acid groups and salts thereof (sodium salts, etc.), etc.

[0034] Specific examples of aromatic dicarboxylic acids constituting the other aromatic dicarboxylic acid units other than terephthalic acid units include, but are not limited to, isophthalic acid, naphthalenedicarboxylic acid, 2-chloroterephthalic acid, 2-methylterephthalic acid, 5-methylisophthalic acid, 5-sodiumsulfoisophthalic acid, and other unsubstituted or predetermined substituent-substituted aromatic dicarboxylic acids having 8 to 20 carbon atoms. The aromatic dicarboxylic acids constituting the other aromatic dicarboxylic acid units may be used alone or in combination of two or more.

[0035] (Aliphatic Dicarboxylic Acid Unit) Examples of aliphatic dicarboxylic acids constituting the aliphatic dicarboxylic acid unit include, but are not limited to, malonic acid, dimethylmalonic acid, succinic acid, 2,2-dimethylsuccinic acid, 2,3-dimethylglutaric acid, 2,2-diethylsuccinic acid, 2,3-diethylglutaric acid, glutaric acid, 2,2-dimethylglutaric acid, adipic acid, 2-methyladipic acid, trimethyladipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, dodecanedioic acid, tetradecanedioic acid, hexadecanedioic acid, octadecanedioic acid, eicosane dioic acid, diglycolic acid, and other linear or branched saturated aliphatic dicarboxylic acids having 3 to 20 carbon atoms. The aliphatic dicarboxylic acids constituting the aliphatic dicarboxylic acid unit may be used alone or in combination of two or more.

[0036] (Alicyclic Dicarboxylic Acid Unit) Examples of alicyclic dicarboxylic acids constituting the alicyclic dicarboxylic acid unit include, but are not limited to, alicyclic dicarboxylic acids having an alicyclic structure with 3 to 10 carbon atoms, and alicyclic dicarboxylic acids having an alicyclic structure with 5 to 10 carbon atoms are preferred. Examples of such alicyclic dicarboxylic acids include, but are not limited to, 1,4-cyclohexanedicarboxylic acid, 1,3-cyclohexanedicarboxylic acid, and 1,3-cyclopentanedicarboxylic acid. Of these, 1,4-cyclohexanedicarboxylic acid is preferred. The alicyclic dicarboxylic acids constituting the alicyclic dicarboxylic acid unit may be used alone or in combination of two or more.

[0037] The alicyclic group of the alicyclic dicarboxylic acid may be unsubstituted or may have a substituent, and examples of the substituent include, but are not limited to, alkyl groups having 1 to 4 carbon atoms, such as a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, and a tert-butyl group.

[0038] In the (B) crystalline semi-aromatic polyamide, the dicarboxylic acid constituting the (B-a) dicarboxylic acid unit is not limited to the compounds described above as dicarboxylic acids, but may also be a compound equivalent to the dicarboxylic acid. Here, "a compound equivalent to a dicarboxylic acid" refers to a compound that can form a dicarboxylic acid structure similar to the dicarboxylic acid structure derived from the dicarboxylic acid. Examples of such compounds include, but are not limited to, anhydrides and halides of dicarboxylic acids.

[0039] Furthermore, the crystalline semi-aromatic polyamide (B) may further contain, as necessary, structural units derived from a trivalent or higher polycarboxylic acid such as trimellitic acid, trimesic acid, or pyromellitic acid, within the scope of the present invention, and the trivalent or higher polycarboxylic acid may be used alone or in combination of two or more.

[0040] [(B-b) Diamine Units] The (B-b) diamine units constituting the (B) crystalline semi-aromatic polyamide preferably contain diamine units having 4 to 10 carbon atoms in an amount of at least 50 mol % relative to the total amount of the (B-b) diamine units. Examples of the (B-b) diamine units include, but are not limited to, aliphatic diamine units, alicyclic diamine units, and aromatic diamine units. The (B-b) diamine units may be of one type alone or a combination of two or more types.

[0041] (Aliphatic diamine unit) The aliphatic diamine constituting the aliphatic diamine unit may be linear or branched. Examples of the linear aliphatic diamine constituting the aliphatic diamine unit include, but are not limited to, linear saturated aliphatic diamines having 2 to 20 carbon atoms, such as ethylenediamine, propylenediamine, tetramethylenediamine, pentamethylenediamine, hexamethylenediamine, heptamethylenediamine, octamethylenediamine, nonamethylenediamine, decamethylenediamine, undecamethylenediamine, dodecamethylenediamine, and tridecamethylenediamine. Examples of branched-chain aliphatic diamines constituting the aliphatic diamine unit having a substituent branched from the main chain include, but are not limited to, branched-chain saturated aliphatic diamines having 3 to 20 carbon atoms, such as 2-methylpentamethylenediamine (also referred to as 2-methyl-1,5-diaminopentane), 2,2,4-trimethylhexamethylenediamine, 2,4,4-trimethylhexamethylenediamine, 2-methyl-1,8-octanediamine (also referred to as 2-methyloctamethylenediamine), and 2,4-dimethyloctamethylenediamine. The aliphatic diamines constituting the aliphatic diamine unit may be used alone or in combination of two or more.

[0042] (Alicyclic diamine unit) Examples of alicyclic diamines constituting the alicyclic diamine unit include, but are not limited to, 1,4-cyclohexanediamine, 1,3-cyclohexanediamine, 1,3-cyclopentanediamine, etc. The alicyclic diamines constituting the alicyclic diamine unit may be used alone or in combination of two or more.

[0043] (Aromatic diamine unit) The aromatic diamine constituting the aromatic diamine unit is not limited to the following as long as it is a diamine containing an aromatic group, and examples thereof include metaxylylenediamine, paraxylylenediamine, etc. The aromatic diamine constituting the aromatic diamine unit may be used alone or in combination of two or more.

[0044] Among the above diamine units, the (B-b) diamine unit is preferably an aliphatic diamine unit, more preferably a diamine unit having a linear or branched saturated aliphatic group having from 4 to 10 carbon atoms, still more preferably a diamine unit having a linear or branched saturated aliphatic group having from 4 to 8 carbon atoms, and particularly preferably a combination of a diamine unit having a linear or branched saturated aliphatic group having from 4 to 6 carbon atoms. Use of such diamines tends to result in a polyamide resin composition that is more excellent in mechanical properties, particularly water absorption rigidity, rigidity when heated, fluidity, surface appearance, resistance to dielectric breakdown, impact resistance under low temperature conditions, etc.

[0045] The crystalline semi-aromatic polyamide (B) may further contain, as necessary, a structural unit derived from a trivalent or higher polyvalent aliphatic amine such as bishexamethylenetriamine, within the range not impairing the effects of the present invention. The trivalent or higher polyvalent aliphatic amine may be used alone or in combination of two or more.

[0046] Specific examples of (B) crystalline semi-aromatic polyamides include polyamide 4T, 4T / 6T, 4T / 2Me5T, 4T / 6T / 66, 4T / 6T / 46, 4T / 6T / 2Me5T, 5T, 6T / 2Me5T, 6T / 6I, 8T, 9T, and 10T. Of these, a skeleton containing 4T is preferred, with 4T / 6T, 6T / 2Me5T, or 4T / 2Me5T or any copolyamide thereof being more preferred, and 4T / 6T being particularly preferred.

[0047] [At least one unit selected from the group consisting of lactam units and aminocarboxylic acid units] The crystalline semi-aromatic polyamide (B) may further contain at least one structural unit selected from the group consisting of lactam units and aminocarboxylic acid units. By including such units, the polyamide tends to have better toughness.

[0048] The lactam and aminocarboxylic acid constituting the lactam unit and aminocarboxylic acid unit are not limited to the following, but are preferably lactams and aminocarboxylic acids having from 4 to 14 carbon atoms, and more preferably lactams and aminocarboxylic acids having from 6 to 12 carbon atoms. Here, the lactam and aminocarboxylic acid constituting the lactam unit and aminocarboxylic acid unit refer to lactams and aminocarboxylic acids that can be polymerized (condensed).

[0049] Examples of lactams constituting the lactam units include, but are not limited to, butyrolactam, pivalolactam, ε-caprolactam, caprylolactam, enantholactam, undecanolactam, and laurolactam (dodecanolactam). Among these, ε-caprolactam or laurolactam is preferred, and ε-caprolactam is more preferred. By including such a lactam, the polyamide resin composition tends to have better toughness.

[0050] Examples of aminocarboxylic acids constituting the aminocarboxylic acid unit include, but are not limited to, ω-aminocarboxylic acids, which are compounds formed by ring-opening of lactams, and α,ω-amino acids. Preferred aminocarboxylic acids are linear or branched saturated aliphatic carboxylic acids having from 4 to 14 carbon atoms and substituted with an amino group at the ω position. Examples of such aminocarboxylic acids include, but are not limited to, 6-aminocaproic acid, 11-aminoundecanoic acid, and 12-aminododecanoic acid. Other examples of aminocarboxylic acids include para-aminomethylbenzoic acid.

[0051] The lactam and aminocarboxylic acid constituting the lactam unit and aminocarboxylic acid unit may each be used alone or in combination of two or more kinds.

[0052] The total proportion (mol %) of lactam units and aminocarboxylic acid units is preferably 0 mol % or more and 20 mol % or less, more preferably 0 mol % or more and 10 mol % or less, and even more preferably 0 mol % or more and 5 mol % or less, based on the total polyamide. When the total proportion of lactam units and aminocarboxylic acid units is within the above range, effects such as improved fluidity tend to be obtained.

[0053] In the polyamide resin composition of this embodiment, the content of the (B) crystalline semi-aromatic polyamide is 10.0% by mass or more and 40.0% by mass or less, preferably 12.5% ​​by mass or more and 37.5% by mass or less, more preferably 15.0% by mass or more and 35.0% by mass or less, even more preferably 17.5% by mass or more and 32.5% by mass or less, even more preferably 20.0% by mass or more and 30.0% by mass or less, and particularly preferably 25.0% by mass or more and 30.0% by mass or less, based on the total mass of all polyamides in the polyamide resin composition (100% by mass). By setting the content of the (B) crystalline semi-aromatic polyamide within the above range, a polyamide resin composition having excellent mechanical properties, particularly mechanical strength under hot and wet heat conditions, impact resistance under low-temperature conditions, and tracking resistance can be obtained. Furthermore, when a component such as the (C) inorganic filler described below is further added, the polyamide resin composition tends to have excellent surface appearance when molded into a molded product.

[0054] <End-capping agent> At least one polyamide selected from the group consisting of (A) crystalline aliphatic polyamide and (B) crystalline semi-aromatic polyamide contained in the polyamide resin composition of this embodiment may have terminals blocked with an end-capping agent. Such an end-capping agent can also be added as a molecular weight modifier when producing a polyamide from the above-mentioned dicarboxylic acid, diamine, and, optionally, at least one compound selected from the group consisting of lactam and aminocarboxylic acid.

[0055] Examples of the end-capping agent include, but are not limited to, acid anhydrides, monoisocyanates, monoacid halides, monoesters, and monoalcohols. Examples of the acid anhydride include monocarboxylic acids, monoamines, and phthalic anhydride. Among these, monocarboxylic acids and monoamines are preferred. When the polyamide ends are blocked with an end-capping agent, the resulting polyamide resin composition tends to have better thermal stability. The end-capping agent may be used alone or in combination of two or more.

[0056] Monocarboxylic acids that can be used as end-capping agents may be any monocarboxylic acid that is reactive with amino groups that may be present at the terminals of polyamides. Specific examples of monocarboxylic acids include, but are not limited to, aliphatic monocarboxylic acids, alicyclic monocarboxylic acids, and aromatic monocarboxylic acids. Examples of aliphatic monocarboxylic acids include, but are not limited to, formic acid, 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. Examples of alicyclic monocarboxylic acids include, but are not limited to, cyclohexanecarboxylic acid. Examples of aromatic monocarboxylic acids include, but are not limited to, benzoic acid, toluic acid, α-naphthalenecarboxylic acid, β-naphthalenecarboxylic acid, methylnaphthalenecarboxylic acid, and phenylacetic acid. These monocarboxylic acids may be used alone or in combination.

[0057] Monoamines that can be used as end-capping agents may be any monoamine that is reactive with carboxyl groups that may be present at the terminals of polyamides. Specific examples of monoamines include, but are not limited to, aliphatic monoamines, alicyclic monoamines, and aromatic monoamines. Examples of aliphatic monoamines include, but are not limited to, methylamine, ethylamine, propylamine, butylamine, hexylamine, octylamine, decylamine, stearylamine, dimethylamine, diethylamine, dipropylamine, and dibutylamine. Examples of alicyclic monoamines include, but are not limited to, cyclohexylamine and dicyclohexylamine. Examples of aromatic monoamines include, but are not limited to, aniline, toluidine, diphenylamine, and naphthylamine. These monoamines may be used alone or in combination of two or more.

[0058] Polyamide resin compositions containing polyamides end-capped with an end-capping agent tend to have better heat resistance, flowability, toughness, low water absorption, rigidity, corrosion resistance, dielectric breakdown resistance, and impact resistance under low-temperature conditions.

[0059] <Method of manufacturing polyamide> A method of manufacturing the polyamide contained in the polyamide resin composition of this embodiment will be described. When manufacturing each polyamide, it is preferable that the amount of dicarboxylic acid and the amount of diamine added are approximately the same molar amount. Taking into account the amount of diamine that escapes to the outside of the reaction system during the polymerization reaction, the molar amount of all diamines relative to the molar amount of all dicarboxylic acids is preferably 0.9 to 1.2, more preferably 0.95 to 1.1, and even more preferably 0.98 to 1.05.

[0060] The method for producing polyamide may include, but is not limited to, the following polymerization step (1) and, if necessary, polymerization step (2): (1) a step of polymerizing a combination of a dicarboxylic acid constituting the dicarboxylic acid unit and a diamine constituting the diamine unit to obtain a polymer, and (2) a step of polymerizing one or more selected from the group consisting of a lactam constituting the lactam unit and an aminocarboxylic acid constituting the aminocarboxylic acid unit to obtain a polymer.

[0061] The method for producing a polyamide preferably further comprises, after the polymerization step, an increasing step of increasing the degree of polymerization of the polyamide. If necessary, the method may comprise, after the polymerization step and the increasing step, a capping step of capping the ends of the resulting polymer with an end-capping agent.

[0062] Specific methods for producing polyamides include various methods, such as those exemplified below in 1) to 4). 1) A method in which an aqueous solution or suspension of one or more selected from the group consisting of a dicarboxylic acid-diamine salt, a mixture of a dicarboxylic acid and a diamine, a lactam, and an aminocarboxylic acid is heated and polymerized while maintaining the molten state (hereinafter, sometimes referred to as a "thermal melt polymerization method"). 2) A method in which the degree of polymerization of the polyamide obtained by the thermal melt polymerization method is increased while maintaining the solid state at a temperature below the melting point (hereinafter, sometimes referred to as a "thermal melt polymerization / solid-state polymerization method"). 3) A method in which one or more selected from the group consisting of a dicarboxylic acid-diamine salt, a mixture of a dicarboxylic acid and a diamine, a lactam, and an aminocarboxylic acid is polymerized while maintaining the solid state (hereinafter, sometimes referred to as a "solid-state polymerization method"). 4) A method in which a dicarboxylic acid halide component equivalent to the dicarboxylic acid and a diamine component are polymerized (hereinafter, sometimes referred to as a "solution method").

[0063] Among these, a specific method for producing polyamide is preferably a production method including a hot melt polymerization method. Furthermore, when producing polyamide by hot melt polymerization, it is preferable to maintain the molten state until the polymerization is completed. Maintaining the molten state requires production under polymerization conditions suitable for polyamide. Examples of polymerization conditions include the following: First, the polymerization pressure in the hot melt polymerization method is controlled to 14 kg / cm or more and 25 kg / cm or less (gauge pressure), and heating is continued. Next, the pressure in the vessel is reduced over 30 minutes or more until it reaches atmospheric pressure (gauge pressure: 0 kg / cm).

[0064] In the polyamide production method, the polymerization mode is not particularly limited, and may be a batch type or a continuous type. The polymerization apparatus used for the polyamide production is not particularly limited, and known apparatuses can be used. Specific examples of the polymerization apparatus include an autoclave type reactor, a tumbler type reactor, and an extruder type reactor (e.g., a kneader).

[0065] The following describes a method for producing polyamide by batch-type melt polymerization, but the method is not limited thereto. First, an aqueous solution containing about 40% to 60% by weight of polyamide raw materials (a combination of dicarboxylic acid and diamine, and optionally at least one selected from the group consisting of lactam and aminocarboxylic acid) is prepared. The aqueous solution is then concentrated to about 65% to 90% by weight in a concentration tank operated at a temperature of 110°C to 180°C and a pressure of about 0.035 MPa to 0.6 MPa (gauge pressure) to obtain a concentrated solution. The resulting concentrated solution is then transferred to an autoclave and heated until the pressure in the autoclave reaches about 1.2 MPa to 2.2 MPa (gauge pressure). The pressure in the autoclave is then maintained at about 1.2 MPa to 2.2 MPa (gauge pressure) while removing at least one of water and gas components. Next, when the temperature reaches about 220°C or higher and 260°C or lower, the pressure is reduced to atmospheric pressure (gauge pressure: 0 MPa). After the pressure inside the autoclave is reduced to atmospheric pressure, the pressure can be reduced as needed to effectively remove the by-product water. The autoclave is then pressurized with an inert gas such as nitrogen, and the polyamide melt is extruded from the autoclave as strands. The extruded strands are cooled and cut to obtain polyamide pellets.

[0066] <Polymer Terminals of Polyamide> The polymer terminals of the polyamides ((A) crystalline aliphatic polyamide and (B) crystalline semi-aromatic polyamide) contained in the polyamide resin composition of the present embodiment are not particularly limited, and can be classified and defined as follows: 1) amino terminals, 2) carboxyl terminals, 3) terminals due to a capping agent, and 4) other terminals. 1) Amino terminals are polymer terminals having an amino group (—NH2 group) and derived from a diamine unit. 2) Carboxyl terminals are polymer terminals having a carboxyl group (—COOH group) and derived from a dicarboxylic acid. 3) Terminals due to a capping agent are terminals formed when a capping agent is added during polymerization. Examples of the capping agent include the terminal capping agents described above. 4) Other terminals are polymer terminals not classified into the above 1) to 3). Specific examples of other terminals include terminals formed by deammonia reaction of amino terminals and terminals formed by decarboxylation of carboxyl terminals.

[0067] <Characteristics of Polyamide> [Characteristics of (A) Crystalline Aliphatic Polyamide] The molecular weight, molecular weight distribution, amount of blocked ends, melting point TmA2, crystallization enthalpy ΔH, and tan δ peak temperature of (A) crystalline aliphatic polyamide can be as follows, and specifically, can be measured by the methods shown below.

[0068] (Weight-average molecular weight Mw(A) of (A) crystalline aliphatic polyamide) The weight-average molecular weight (Mw(A)) can be used as an indicator of the molecular weight of (A) crystalline aliphatic polyamide. The weight-average molecular weight (Mw(A)) of (A) crystalline aliphatic polyamide is preferably 10,000 or more and 50,000 or less, more preferably 15,000 or more and 45,000 or less, even more preferably 20,000 or more and 43,000 or less, even more preferably 25,000 or more and 40,000 or less, and particularly preferably 30,000 or more and 35,000 or less. When Mw(A) is within the above range, a polyamide resin composition tends to be obtained that is simultaneously more satisfactory in mechanical properties, particularly mechanical strength under hot and wet heat conditions, flowability, and dielectric breakdown resistance. Furthermore, when a component typified by (C) inorganic filler described below is further contained, molded articles obtained from the polyamide resin composition tend to have better surface appearance. The weight average molecular weight (Mw(A)) of the crystalline aliphatic polyamide (A) can be measured by gel permeation chromatography (GPC).

[0069] (Molecular Weight Distribution of (A) Crystalline Aliphatic Polyamide) The molecular weight distribution of (A) crystalline aliphatic polyamide is indicated by the weight average molecular weight (Mw(A)) of (A) crystalline aliphatic polyamide / number average molecular weight (Mn(A)) of (A) crystalline aliphatic polyamide. Mw(A) / Mn(A) is preferably 1.0 or more, more preferably 1.8 to 2.2, and even more preferably 1.9 to 2.1. When Mw(A) / Mn(A) is within the above range, the (A) crystalline aliphatic polyamide has better compatibility with the (B) crystalline semi-aromatic polyamide, and therefore tends to produce a polyamide resin composition with better mechanical properties, particularly mechanical strength and flowability under hot and wet heat conditions. Furthermore, when a component such as (C) inorganic filler described below is further added, the molded article obtained from the polyamide resin composition tends to have better surface appearance.

[0070] Methods for controlling Mw(A) / Mn(A) within the above range include, for example, the following methods 1) and 2): 1) A method of adding a known polycondensation catalyst such as phosphoric acid or sodium hypophosphite as an additive during the thermal melt polymerization of polyamide; 2) A method of controlling polymerization conditions such as heating conditions and reduced pressure conditions in addition to the above method 1).

[0071] The Mw(A) / Mn(A) can be calculated using the Mw(A) and Mn(A) obtained by GPC.

[0072] (Amount of Capped Ends of (A) Crystalline Aliphatic Polyamide) The amount of capped ends of (A) crystalline aliphatic polyamide is preferably 5 μmol equivalents / g to 180 μmol equivalents / g, more preferably 5 μmol equivalents / g to 150 μmol equivalents / g, even more preferably 10 μmol equivalents / g to 100 μmol equivalents / g, particularly preferably 15 μmol equivalents / g to 80 μmol equivalents / g, and most preferably 20 μmol equivalents / g to 60 μmol equivalents / g. By having the amount of capped ends within the above range, the occurrence of mold deposits (MD) during molding can be suppressed, and a polyamide resin composition can be obtained that is superior in surface appearance, mechanical properties, particularly mechanical strength under hot and wet heat conditions, and impact resistance under low temperature conditions when formed into a molded article. The amount of blocked ends of the crystalline aliphatic polyamide (A) can be measured, for example, by NMR.

[0073] (Melting point TmA2 of (A) crystalline aliphatic polyamide) The lower limit of the melting point TmA2 of the (A) crystalline aliphatic polyamide is preferably 220 ° C, more preferably 230 ° C, and even more preferably 240 ° C. On the other hand, the upper limit of the melting point TmA2 of the (A) crystalline aliphatic polyamide is preferably 300 ° C, more preferably 290 ° C, even more preferably 280 ° C, and particularly preferably 270 ° C. That is, the melting point TmA2 of the (A) crystalline aliphatic polyamide is preferably 220 ° C or higher and 300 ° C or lower, more preferably 230 ° C or higher and 290 ° C or lower, even more preferably 240 ° C or higher and 280 ° C or lower, and particularly preferably 240 ° C or higher and 270 ° C or lower. When the melting point TmA2 of the (A) crystalline aliphatic polyamide is above the above lower limit, the hot rigidity of the molded article obtained from the polyamide resin composition tends to be better. On the other hand, when the melting point TmA2 of the (A) crystalline aliphatic polyamide is equal to or less than the above upper limit, there is a tendency that thermal decomposition of the polyamide resin composition can be further suppressed during melt processing such as extrusion, molding, etc. Examples of devices for measuring the melting point TmA2 of the (A) crystalline aliphatic polyamide include Diamond-DSC manufactured by PERKIN-ELMER.

[0074] (Crystallization enthalpy ΔH of (A) crystalline aliphatic polyamide) From the viewpoint of mechanical properties, particularly mechanical strength under hot and wet heat, the lower limit of the crystallization enthalpy ΔH of (A) crystalline aliphatic polyamide is preferably 30 J / g, more preferably 40 J / g, even more preferably 50 J / g, and particularly preferably 60 J / g. On the other hand, the upper limit of the crystallization enthalpy ΔH of (A) crystalline aliphatic polyamide is not particularly limited, and the higher the upper limit, the better. Examples of devices for measuring the crystallization enthalpy ΔH of (A) crystalline aliphatic polyamide include Diamond-DSC manufactured by Perkin-Elmer.

[0075] (Tan δ Peak Temperature of (A) Crystalline Aliphatic Polyamide) The tan δ peak temperature of the (A) crystalline aliphatic polyamide is preferably 40°C or higher, more preferably 50°C or higher and 110°C or lower, even more preferably 60°C or higher and 100°C or lower, particularly preferably 70°C or higher and 95°C or lower, and most preferably 80°C or higher and 90°C or lower. When the tan δ peak temperature of the (A) crystalline aliphatic polyamide is equal to or higher than the lower limit, the mechanical properties of a molded article obtained from the polyamide resin composition, particularly the mechanical strength in hot and wet heat conditions, and impact resistance under low-temperature conditions, tend to be more excellent. The tan δ peak temperature of the (A) crystalline aliphatic polyamide can be measured, for example, using a viscoelasticity measurement analyzer (DVE-V4 manufactured by Rheology Co., Ltd.) or the like.

[0076] [Characteristics of (B) Crystalline Semi-Aromatic Polyamide] The molecular weight, molecular weight distribution, melting point TmB2, crystallization enthalpy ΔH, tan δ peak temperature, and ratio of the number of carbon atoms C to the number of nitrogen atoms N (C / N ratio) of (B) crystalline semi-aromatic polyamide can be as follows, and specifically can be measured by the method shown below.

[0077] (Weight-average molecular weight Mw(B) of (B) crystalline semi-aromatic polyamide) As an indicator of the molecular weight of (B) crystalline semi-aromatic polyamide, the weight-average molecular weight (Mw(B)) of (B) crystalline semi-aromatic polyamide can be used. The weight-average molecular weight (Mw(B)) of (B) crystalline semi-aromatic polyamide is preferably 5,000 or more and 50,000 or less, more preferably 10,000 or more and 45,000 or less, even more preferably 12,000 or more and 40,000 or less, even more preferably 14,000 or more and 35,000 or less, particularly preferably 16,000 or more and 30,000 or less, and most preferably 20,000 or more and 25,000 or less. Since (B) crystalline semi-aromatic polyamides containing aromatic compound units in the molecular structure of the polyamide have a high melt viscosity when they have the same molecular weight as (A) crystalline aliphatic polyamides, it is desirable that the (B) crystalline semi-aromatic polyamides have a smaller molecular weight than (A) crystalline aliphatic polyamides. That is, when the weight average molecular weight (Mw(B)) of the (B) crystalline semi-aromatic polyamide is within the above range, the molecular weight can be made smaller than that of the (A) crystalline aliphatic polyamide, and when molded into a polyamide resin composition, the resulting polyamide resin composition tends to have better mechanical properties, particularly better mechanical strength and fluidity under hot and wet heat conditions, and better impact resistance and dielectric breakdown resistance under low-temperature conditions. Furthermore, when a component such as the (C) inorganic filler described below is further contained, the molded article obtained from the polyamide resin composition tends to have better surface appearance. The weight average molecular weight (Mw(B)) of the (B) crystalline semi-aromatic polyamide can be measured using GPC.

[0078] (Molecular Weight Distribution of (B) Crystalline Semi-Aromatic Polyamide) The molecular weight distribution of the (B) crystalline semi-aromatic polyamide is indicated by the weight average molecular weight of the (B) crystalline semi-aromatic polyamide (Mw(B)) / the number average molecular weight of the (B) crystalline semi-aromatic polyamide (Mn(B)). Mw(B) / Mn(B) is preferably 1.0 or more and 3.5 or less, more preferably 1.0 or more and 3.0 or less, even more preferably 1.7 or more and 2.5 or less, even more preferably 1.8 or more and 2.3 or less, particularly preferably 1.9 or more and 2.2 or less, and most preferably 1.9 or more and 2.1 or less. By having Mw(B) / Mn(B) in the above range, a polyamide resin composition having excellent flowability, impact resistance under low temperature conditions, etc. tends to be obtained. Furthermore, when a component such as (C) inorganic filler described below is further contained, the molded article obtained from the polyamide resin composition tends to have an excellent surface appearance.

[0079] Methods for controlling Mw(B) / Mn(B) within the above range include, for example, the following methods 1) and 2): 1) A method of adding a known polycondensation catalyst such as phosphoric acid or sodium hypophosphite as an additive during the thermal melt polymerization of polyamide; 2) In addition to the above method 1), a method of controlling polymerization conditions such as heating conditions and reduced pressure conditions to complete the polycondensation reaction at as low a temperature and in as short a time as possible.

[0080] When aromatic compound units are contained in the molecular structure of a polyamide, the molecular weight distribution (Mw / Mn) tends to increase as the molecular weight increases. A high molecular weight distribution indicates a high proportion of polyamide molecules with a three-dimensional molecular structure. Reducing the proportion of polyamide molecules with a three-dimensional molecular structure can improve compatibility with (A) crystalline aliphatic polyamide. Therefore, by controlling Mw(B) / Mn(B) within the above range, the progression of three-dimensional molecular structuring during high-temperature processing is further suppressed, tending to produce a polyamide resin composition with superior fluidity when molded and impact resistance under low-temperature conditions. Furthermore, when a component such as (C) inorganic filler, described below, is further added, the surface appearance of molded articles obtained from the polyamide resin composition tends to be improved. Note that Mw(B) / Mn(B) can be measured and calculated using Mw(B) and Mn(B) obtained using GPC.

[0081] (Melting point TmB2 of (B) crystalline semi-aromatic polyamide) The lower limit of the melting point TmB2 of the (B) crystalline semi-aromatic polyamide is preferably 290 ° C, more preferably 310 ° C, even more preferably 320 ° C, and particularly preferably 330 ° C. On the other hand, the upper limit of the melting point TmB2 of the (B) crystalline semi-aromatic polyamide is preferably 380 ° C, more preferably 370 ° C, even more preferably 360 ° C, and particularly preferably 350 ° C. That is, the melting point TmB2 of the (B) crystalline semi-aromatic polyamide is preferably 290 ° C or higher and 380 ° C or lower, more preferably 310 ° C or higher and 370 ° C or lower, even more preferably 320 ° C or higher and 360 ° C or lower, and particularly preferably 330 ° C or higher and 350 ° C or lower. When the melting point TmB2 of the (B) crystalline semi-aromatic polyamide is above the lower limit, the hot rigidity of the molded article obtained from the polyamide resin composition tends to be better. On the other hand, when the melting point TmB2 of the (B) crystalline semi-aromatic polyamide is equal to or less than the upper limit, there is a tendency that thermal decomposition of the polyamide resin composition can be further suppressed during melt processing such as extrusion, molding, etc. Examples of devices for measuring the melting point TmB2 of the (B) crystalline semi-aromatic polyamide include Diamond-DSC manufactured by PERKIN-ELMER.

[0082] (Crystallization enthalpy ΔH of (B) crystalline semi-aromatic polyamide) From the viewpoint of mechanical properties, particularly mechanical strength under hot and wet heat conditions, and impact resistance, the crystallization enthalpy ΔH of the (B) crystalline semi-aromatic polyamide is preferably 5 J / g or more, more preferably 10 J / g or more, even more preferably 20 J / g or more, even more preferably 30 J / g or more, and particularly preferably 40 J / g or more. As a method for controlling the crystallization enthalpy ΔH of the (B) crystalline semi-aromatic polyamide within the above range, known methods for increasing the crystallinity of polyamides can be used, and are not particularly limited. Specific examples of known methods for increasing the crystallinity of polyamides include a method of increasing the ratio of para-substituted aromatic dicarboxylic acid units to dicarboxylic acid units, and a method of increasing the ratio of para-substituted aromatic diamine units to diamine units. From this viewpoint, the (B) crystalline semi-aromatic polyamide preferably contains, as the (Ba-a) dicarboxylic acid units, terephthalic acid units in an amount of 75 mol % or more, more preferably 90 mol % or more, and particularly preferably 100 mol % of all dicarboxylic acid units constituting the (B) crystalline semi-aromatic polyamide. Examples of a device for measuring the crystallization enthalpy ΔH of the (B) crystalline semi-aromatic polyamide include a Diamond-DSC manufactured by Perkin-Elmer.

[0083] (Tan δ Peak Temperature of (B) Crystalline Semi-Aromatic Polyamide) The tan δ peak temperature of the (B) crystalline semi-aromatic polyamide is preferably 120°C or higher, more preferably 130°C or higher, even more preferably 140°C or higher, particularly preferably 150°C or higher, and most preferably 160°C or higher. When the tan δ peak temperature of the (B) crystalline semi-aromatic polyamide is at least the above-mentioned lower limit, it tends to be possible to obtain a polyamide resin composition that, when formed into a molded article, is superior in water absorption rigidity, hot rigidity, dielectric breakdown resistance, impact resistance under low temperature conditions, and the like. Examples of methods for controlling the tan δ peak temperature of the (B) crystalline semi-aromatic polyamide within the above range include (Ba-a) a method of increasing the ratio of aromatic monomer units in dicarboxylic acid units. From this viewpoint, the crystalline semi-aromatic polyamide (B) preferably contains terephthalic acid units in an amount of 75 mol % or more, more preferably 90 mol % or more, and particularly preferably 100 mol % based on the total moles of the dicarboxylic acid units (Ba-a). The tan δ peak temperature of the crystalline semi-aromatic polyamide (B) can be measured, for example, using a viscoelasticity measurement analyzer (DVE-V4 manufactured by Rheology Co., Ltd.).

[0084] (C / N Ratio of (B) Crystalline Semi-Aromatic Polyamide) In the polyamide resin composition of this embodiment, the ratio of the number of carbon atoms C to the number of nitrogen atoms N in the (B) crystalline semi-aromatic polyamide (C / N ratio) is greater than 6.00 and less than 7.00, preferably greater than 6.15 and less than 6.90, more preferably greater than 6.30 and less than 6.85, even more preferably greater than 6.45 and less than 6.75, and particularly preferably greater than 6.50 and less than 6.70. When the C / N ratio of the (B) crystalline semi-aromatic polyamide is within the above range, it is easily and moderately miscible with the (A) crystalline aliphatic polyamide, and therefore the tan δ peak temperature of the polyamide resin composition tends to be higher, and a polyamide resin composition having better mechanical properties, particularly mechanical strength under hot and wet heat conditions, impact resistance, tracking resistance, and dielectric breakdown resistance characteristics under low-temperature conditions, etc., tends to be obtained.

[0085] <Other Components> In addition to the (A) crystalline aliphatic polyamide and the (B) crystalline semi-aromatic polyamide, the polyamide resin composition of the present embodiment may further include one or more components selected from the group consisting of (C) an inorganic filler, (D) at least one metal phosphate selected from the group consisting of metal phosphites and metal hypophosphites, (E) a lubricant, (F) an elastomer, (G) carbon black, (H) a phosphorus-based flame retardant, (I) a nucleating agent, (J) a heat stabilizer, (K) other polymers, and (L) other additives.

[0086] [(C) Inorganic Filler] Examples of (C) inorganic fillers include, but are not limited to, glass fibers, carbon fibers, calcium silicate fibers, potassium titanate fibers, aluminum borate fibers, clay, glass flakes, talc, kaolin, mica, hydrotalcite, calcium carbonate, magnesium carbonate, zinc carbonate, zinc oxide, calcium hydrogen phosphate, wollastonite, silica, zeolite, alumina, boehmite, aluminum hydroxide, 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, apatite, etc. These inorganic fillers may be used alone or in combination of two or more. Among these, from the viewpoint of further improving mechanical strength, one or more selected from the group consisting of glass fiber, carbon fiber, wollastonite, kaolin, mica, talc, calcium carbonate, magnesium carbonate, potassium titanate fiber, aluminum borate fiber, and clay are preferred. Among these, one or more selected from the group consisting of glass fiber, carbon fiber, wollastonite, kaolin, mica, talc, calcium carbonate, and clay are more preferred. In this specification, a component that corresponds to both (C) inorganic filler and (I) nucleating agent is treated as (C) inorganic filler.

[0087] When the (C) inorganic filler is glass fiber or carbon fiber, the number-average fiber diameter (d) is preferably 3 μm or more and 30 μm or less, more preferably 3 μm or more and 20 μm or less, even more preferably 3 μm or more and 12 μm or less, particularly preferably 3 μm or more and 9 μm or less, and most preferably 4 μm or more and 6 μm or less. By setting the number-average fiber diameter (d) to the above upper limit or less, a polyamide resin composition with excellent toughness and surface appearance of a molded article tends to be obtained. On the other hand, by setting the number-average fiber diameter (d) to the above lower limit or more, a polyamide resin composition with an excellent balance between cost, powder handling, and physical properties (fluidity, etc.) tends to be obtained. Furthermore, by setting the number-average fiber diameter (d) to 3 μm or more and 9 μm or less, a polyamide resin composition with excellent vibration fatigue properties and sliding properties tends to be obtained.

[0088] When the (C) inorganic filler is glass fiber or carbon fiber, from the viewpoint of imparting excellent mechanical strength to the polyamide resin composition, it is particularly preferred that the number average fiber diameter (d) is 3 μm or more and 30 μm or less, the weight average fiber length (l) is 100 μm or more and 750 μm or less, and the ratio of the weight average fiber length (l) to the number average fiber diameter (d), i.e., the aspect ratio (l / d), is 10 or more and 100 or less.

[0089] The "number average fiber diameter (d)" and "weight average fiber length (l)" in this specification can be determined by the following method. First, a polyamide resin composition is placed in an electric furnace, and the organic matter contained therein is incinerated. From the residue after the treatment, 100 or more glass fibers (or carbon fibers) are arbitrarily selected, and their cross sections are observed with a scanning electron microscope (SEM). The total measured major diameter (d2) of these glass fibers (or carbon fibers) is divided by the number of measured glass fibers (or carbon fibers), thereby determining the number average fiber diameter (d). In addition, the weight average fiber length (l) can be determined by dividing the total fiber length measured using an SEM photograph of the 100 or more glass fibers (or carbon fibers) taken at 1000x magnification by the total mass of the measured glass fibers (or carbon fibers).

[0090] When the (C) inorganic filler is glass fiber or carbon fiber, its cross section may be a perfect circle or a flattened shape. Examples of such a flattened cross section include, but are not limited to, a rectangle, an oval close to a rectangle, an ellipse, and a cocoon shape with a narrowed central portion in the longitudinal direction.

[0091] Furthermore, from the viewpoint of reducing warpage of the plate-shaped molded body and improving heat resistance, toughness, low water absorption, and heat aging resistance, the aspect ratio is preferably 1.5 or more, more preferably 1.5 to 10.0, even more preferably 2.5 to 10.0, particularly preferably more than 3.0 to 6.0, and most preferably 3.1 to 6.0. Having the aspect ratio within the above range makes it possible to more effectively prevent crushing during processing such as mixing with other components, kneading, and molding, and to more fully achieve the desired effects for the molded body. Here, the term "aspect ratio" as used herein refers to the value expressed by d2 / d1, where d2 is the major axis of the fiber cross section of the glass fiber (or carbon fiber) and d1 is the minor axis of the fiber cross section (in the case of a perfect circle, the aspect ratio is approximately 1). The major axis (d2) and minor axis (d1) of the glass fibers (or carbon fibers) can be determined as the average values ​​of the major axis and minor axis measured by observing the cross sections of 100 or more glass fibers (or carbon fibers) with an SEM as described above.

[0092] The thickness of glass fibers or carbon fibers having an aspect ratio of 1.5 or more is not limited to the following, but it is preferable that the minor axis (d1) of the fiber cross section is 0.5 μm or more and 25 μm or less and the major axis (d2) of the fiber cross section is 1.25 μm or more and 250 μm or less, and it is more preferable that the minor axis (d1) of the fiber cross section is 3.0 μm or more and 25 μm or less and the major axis (d2) of the fiber cross section is 1.25 μm or more and 250 μm or less. By having the minor axis (d1) and the major axis (d2) within the above ranges, it is possible to more effectively avoid difficulties in spinning the fibers and to further improve the strength of the molded body without reducing the contact area with the resin (polyamide).

[0093] The glass fibers or carbon fibers having an aspect ratio of 1.5 or more are preferably glass fibers or carbon fibers produced using either an orifice plate having a large number of orifices on its bottom surface, the orifice plate having a convex edge extending downward from the bottom surface surrounding the orifice outlets, or a nozzle tip for spinning modified cross section glass fibers having a nozzle tip having one or more orifice holes and having a plurality of convex edges extending downward from the tip of the outer periphery. These inorganic fillers may be used as rovings in the form of fiber strands, or may be further cut and used as chopped glass strands.

[0094] Furthermore, the glass fibers or carbon fibers may be surface-treated with a silane coupling agent or the like. Examples of silane coupling agents include, but are not limited to, aminosilanes, mercaptosilanes, epoxysilanes, and vinylsilanes. Examples of aminosilanes include γ-aminopropyltriethoxysilane, γ-aminopropyltrimethoxysilane, and N-β-(aminoethyl)-γ-aminopropylmethyldimethoxysilane. Examples of mercaptosilanes include γ-mercaptopropyltrimethoxysilane and γ-mercaptopropyltriethoxysilane. These silane coupling agents may be used alone or in combination of two or more. Among these, aminosilanes are preferred as silane coupling agents.

[0095] Glass fibers or carbon fibers may further contain a sizing agent. Examples of sizing agents include copolymers containing, as structural units, a carboxylic acid anhydride-containing unsaturated vinyl monomer and an unsaturated vinyl monomer other than the carboxylic acid anhydride-containing unsaturated vinyl monomer, epoxy compounds, polyurethane resins, homopolymers of acrylic acid, copolymers of acrylic acid and other copolymerizable monomers, and salts of these with primary, secondary, and tertiary amines. These sizing agents may be used alone or in combination of two or more. Among these, from the viewpoint of the mechanical strength of the resulting polyamide resin composition, the sizing agent is preferably one or more selected from the group consisting of copolymers containing, as structural units, a carboxylic acid anhydride-containing unsaturated vinyl monomer and an unsaturated vinyl monomer other than the carboxylic acid anhydride-containing unsaturated vinyl monomer, epoxy compounds, and polyurethane resins. Also, one or more selected from the group consisting of copolymers and polyurethane resins containing, as constituent units, a carboxylic acid anhydride-containing unsaturated vinyl monomer and an unsaturated vinyl monomer other than a carboxylic acid anhydride-containing unsaturated vinyl monomer are more preferred.

[0096] Glass fibers or carbon fibers containing a sizing agent are obtained by continuously reacting the sizing agent with the fibers in a known fiber production process by applying the sizing agent to the fibers using a known method such as a roller applicator, and then drying the produced fiber strand. The fiber strand may be used as a roving as is, or may be further cut to be used as chopped glass strands. The strands may be dried after the cutting step, or may be cut after drying.

[0097] The sizing agent is preferably added in an amount of about 0.2% by mass or more and about 3% by mass or less, and more preferably about 0.3% by mass or more and about 2% by mass or less, in terms of solid content, relative to the total mass of the glass fibers or carbon fibers. When the amount of sizing agent added is equal to or greater than the above-mentioned lower limit in terms of solid content, relative to the total mass of the glass fibers or carbon fibers, the bundling of the fibers can be more effectively maintained. On the other hand, when the amount of sizing agent added is equal to or less than the above-mentioned upper limit in terms of solid content, relative to the total mass of the glass fibers or carbon fibers, the thermal stability of the resulting polyamide resin composition can be further improved.

[0098] From the viewpoint of improving the strength, rigidity, and surface appearance of the molded body, inorganic fillers other than glass fiber and carbon fiber are preferably wollastonite, kaolin, mica, talc, calcium carbonate, magnesium carbonate, potassium titanate fiber, aluminum borate fiber, or clay, more preferably wollastonite, kaolin, mica, talc, calcium carbonate, or clay, still more preferably wollastonite, kaolin, mica, or talc, and particularly preferably wollastonite, mica, or talc. These inorganic fillers may be used alone or in combination of two or more.

[0099] From the viewpoint of improving toughness and the surface appearance of a molded article, the average particle size of the inorganic filler other than glass fiber and carbon fiber is preferably 0.01 μm or more and 38 μm or less, more preferably 0.03 μm or more and 30 μm or less, even more preferably 0.05 μm or more and 25 μm or less, even more preferably 0.10 μm or more and 20 μm or less, and particularly preferably 0.15 μm or more and 15 μm or less. By setting the average particle size of the inorganic filler other than glass fiber and carbon fiber to the above upper limit or less, a polyamide resin composition that is superior in toughness and surface appearance of a molded article tends to be obtained. On the other hand, by setting the average particle size to the above lower limit or more, a polyamide resin composition that is superior in balance between cost, powder handling, and physical properties (fluidity, etc.) tends to be obtained.

[0100] For needle-shaped inorganic fillers other than glass fiber and carbon fiber, such as wollastonite, the number average particle diameter (dn) is taken as the average particle diameter. If the cross section is not circular, the maximum length of the cross section is taken as the particle diameter. The number average particle length (ln) of the needle-shaped inorganic filler is preferably within the range calculated from the preferred range of the number average particle diameter (dn) described above and the preferred range of the aspect ratio (ln / dn) of the number average particle length (ln) to the number average particle diameter (dn) described below.

[0101] The aspect ratio (ln / dn) of the number average particle length (ln) to the number average particle diameter (dn) of the acicular inorganic filler is preferably 1.5 or more and 10 or less, more preferably 2.0 or more and 5 or less, and even more preferably 2.5 or more and 4 or less, from the viewpoint of improving the surface appearance of the molded body and preventing wear of metal parts of an injection molding machine or the like.

[0102] In this specification, the "number average particle diameter (dn)" and "number average particle length (ln)" can be determined by the following method. First, the polyamide resin composition is placed in an electric furnace and the organic matter contained therein is incinerated. From the residue after the treatment, 100 or more acicular inorganic fillers are arbitrarily selected, and the cross-sections are observed with a scanning electron microscope (SEM). The total of the measured major axes (dn2) of these acicular inorganic fillers is divided by the number of acicular inorganic fillers measured, thereby determining the number average particle diameter (dn). In addition, the total fiber length measured using SEM photographs of the 100 or more acicular inorganic fillers taken at 1000x magnification can be determined by dividing the total number of acicular inorganic fillers measured.

[0103] In addition, inorganic fillers other than glass fiber and carbon fiber may be surface-treated using a silane coupling agent, a titanate-based coupling agent, or the like. Examples of silane coupling agents include those exemplified for glass fiber and carbon fiber above. Among these, aminosilanes are preferred as silane coupling agents. Such surface treatment agents may be applied to the surface of the inorganic filler in advance, or may be added when mixing the polyamide and the inorganic filler. The amount of surface treatment agent added is preferably 0.05% by mass or more and 1.5% by mass or less, based on the total mass of the inorganic filler.

[0104] The content of the (C) inorganic filler is preferably 5 parts by mass or more and 250 parts by mass or less, more preferably 20 parts by mass or more and 200 parts by mass or less, even more preferably 30 parts by mass or more and 175 parts by mass or less, particularly preferably 50 parts by mass or more and 150 parts by mass or less, and most preferably 75 parts by mass or more and 150 parts by mass or less, relative to 100 parts by mass of the total mass of the (A) crystalline aliphatic polyamide and the (B) crystalline semi-aromatic polyamide. By making the content of the (C) inorganic filler equal to or more than the lower limit, the effect of further improving the strength, impact resistance, and rigidity of the obtained molded body is exhibited. On the other hand, by making the content of the (C) inorganic filler equal to or less than the upper limit, a polyamide resin composition with better extrudability and moldability tends to be obtained.

[0105] [(D) At least one selected from the group consisting of metal phosphites and metal hypophosphites] The metal phosphites and metal hypophosphites are not particularly limited, and examples thereof include salts of phosphorous acid, hypophosphorous acid, pyrophosphorous acid, or diphosphorous acid with elements of Groups 1 and 2 of the periodic table, manganese, zinc, aluminum, ammonia, alkylamines, cycloalkylamines, or diamines. Among these, the metal phosphites and metal hypophosphites are preferably sodium hypophosphite, calcium hypophosphite, or magnesium hypophosphite.

[0106] The inclusion of (D) at least one selected from the group consisting of metal phosphites and metal hypophosphites tends to enable the production of a polyamide resin composition having superior extrusion processability, molding process stability, yellowing resistance, and transamidation reactivity. The content of (D) at least one selected from the group consisting of metal phosphites and metal hypophosphites is preferably 0.001 parts by mass or more and 0.5 parts by mass or less, more preferably 0.005 parts by mass or more and 0.1 parts by mass or less, and even more preferably 0.007 parts by mass or more and 0.05 parts by mass or less, per 100 parts by mass of the total mass of (A) the crystalline aliphatic polyamide and the (B) crystalline semi-aromatic polyamide. By making the content of (D) at least one selected from the group consisting of metal phosphites and metal hypophosphites equal to or greater than the lower limit, the exchange reaction between (A) the crystalline aliphatic polyamide and (B) the crystalline semi-aromatic polyamide proceeds appropriately, and the amount of interface area between (A) the crystalline aliphatic polyamide and (B) the crystalline semi-aromatic polyamide increases, which tends to further improve impact resistance, particularly impact resistance at low temperatures. By making the content of (D) at least one selected from the group consisting of metal phosphites and metal hypophosphites equal to or less than the upper limit, it tends to be possible to more effectively prevent the polyamide resin composition from decreasing in Tan δ peak temperature, tracking resistance, and dielectric breakdown resistance.

[0107] [(E) Lubricant] The (E) lubricant 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. Lubricants can also be used as molding improvers. By adding a (E) lubricant to the polyamide resin composition of this embodiment, in which the (B) crystalline semi-aromatic polyamide is dispersed in the (A) crystalline aliphatic polyamide to form domains, molecular mobility can be further improved, and impact resistance under low-temperature conditions can be further improved. One type of (E) lubricant may be used alone, or two or more types may be used in combination.

[0108] (Higher Fatty Acids) The higher fatty acids are not particularly limited, and examples thereof include linear or branched, saturated or unsaturated aliphatic monocarboxylic acids having from 8 to 40 carbon atoms. Examples of linear or branched, saturated or unsaturated aliphatic monocarboxylic acids having from 8 to 40 carbon atoms include lauric acid, palmitic acid, stearic acid, behenic acid, and montanic acid. Examples of branched saturated aliphatic monocarboxylic acids having from 8 to 40 carbon atoms include isopalmitic acid and isostearic acid. Examples of linear unsaturated aliphatic monocarboxylic acids having from 8 to 40 carbon atoms include oleic acid and erucic acid. Examples of branched unsaturated aliphatic monocarboxylic acids having from 8 to 40 carbon atoms include isooleic acid. Among these, stearic acid and montanic acid are preferred as the higher fatty acid.

[0109] (Higher fatty acid metal salt) A higher fatty acid metal salt is a metal salt of a higher fatty acid. Examples of the metal element of the metal salt include Group 1 elements, Group 2 elements, and Group 3 elements of the periodic table, zinc, aluminum, etc. Examples of Group 1 elements of the periodic table include sodium and potassium, etc. Examples of Group 2 elements of the periodic table include calcium and magnesium, etc. Examples of Group 3 elements of the periodic table include scandium and yttrium, etc. Among these, Group 1 and Group 2 elements of the periodic table, or aluminum are preferred, and sodium, potassium, calcium, magnesium, or aluminum is more preferred.

[0110] Specific examples of higher fatty acid metal salts include calcium stearate, aluminum stearate, zinc stearate, magnesium stearate, calcium montanate, sodium montanate, calcium palmitate, etc. Among these, metal salts of montanic acid or metal salts of stearic acid are preferred as higher fatty acid metal salts.

[0111] (Higher fatty acid ester) A higher fatty acid ester is an esterification product of a higher fatty acid and an alcohol. As the higher fatty acid ester, an ester of an aliphatic carboxylic acid having from 8 to 40 carbon atoms and an aliphatic alcohol having from 8 to 40 carbon atoms is preferred. Examples of the aliphatic alcohol having from 8 to 40 carbon atoms include stearyl alcohol, behenyl alcohol, lauryl alcohol, etc. Specific examples of the higher fatty acid ester include stearyl stearate, behenyl behenate, etc.

[0112] (Higher fatty acid amide) The higher fatty acid amide is an amide compound of a higher fatty acid. Examples of the higher fatty acid amide include, but are not limited to, stearic acid amide, oleic acid amide, erucic acid amide, ethylene bisstearylamide, ethylene bisoleylamide, N-stearyl stearic acid amide, and N-stearyl erucic acid amide.

[0113] These higher fatty acids, higher fatty acid metal salts, higher fatty acid esters and higher fatty acid amides may be used singly or in combination of two or more.

[0114] The content of the lubricant (E) is preferably 0.01% by mass or more and 1% by mass or less, more preferably 0.05% by mass or more and 0.5% by mass or less, and even more preferably 0.08% by mass or more and 0.2% by mass or less, relative to the total mass of the polyamide resin composition. By setting the content of the lubricant (E) within the above upper and lower limit ranges relative to the total amount of the polyamide resin composition, the effect of further improving the mold releasability, surface appearance, and impact resistance of the obtained molded article is exerted.

[0115] Furthermore, when a higher fatty acid metal salt and a higher fatty acid amide are combined as the lubricant (E), the dispersibility of the lubricants is improved, and molecular mobility is further improved, thereby further improving impact resistance under low-temperature conditions. The mass ratio of the higher fatty acid metal salt to the higher fatty acid amide (mass% of higher fatty acid metal salt / mass% of higher fatty acid amide) is preferably 0.3 to 5.0, more preferably 0.5 to 4.0, even more preferably 1.0 to 3.5, even more preferably 1.5 to 3.4, and particularly preferably 2.0 to 3.0. By setting the mass ratio of the higher fatty acid metal salt to the higher fatty acid amide within the above upper and lower limit values, the effect of further improving the mold releasability, surface appearance, and impact resistance of the resulting molded article is exerted.

[0116] [(F) Elastomer] The polyamide resin composition of the present embodiment may contain (F) an elastomer in addition to the above-described (A) crystalline aliphatic polyamide and (B) crystalline semi-aromatic polyamide.

[0117] The (F) elastomer is not particularly limited, and examples thereof include polymers exhibiting elastic behavior such as hydrogenated styrene-based thermoplastic elastomers, olefin elastomers, urethane elastomers, polyester elastomers, etc. The (F) elastomer may be used alone or in combination of two or more types.

[0118] Examples of hydrogenated styrene-based thermoplastic elastomers include hydrogenated block copolymers having styrene blocks. The hydrogenated block copolymers are not particularly limited, and examples thereof include unmodified hydrogenated block copolymers, modified hydrogenated block copolymers, and mixtures thereof. The hydrogenated block copolymers may be used alone or in combination of two or more. Examples of olefin elastomers include ethylene propylene elastomers.

[0119] Molded articles obtained by molding the polyamide resin composition of this embodiment tend to exhibit vibration damping and noise suppression effects even without containing the elastomer (F). Furthermore, by keeping the content of the elastomer (F) at a predetermined content or less, it is possible to further prevent a decrease in the strength and elastic modulus of the molded article. Therefore, the content of the elastomer (F) is preferably 5% by mass or less, more preferably 3% by mass or less, even more preferably 1% by mass or less, particularly preferably 0.1% by mass or less, and most preferably 0% by mass, based on the total mass of the crystalline aliphatic polyamide (A) and the crystalline semi-aromatic polyamide (B) in the polyamide resin composition.

[0120] [(G) Carbon Black] (G) Carbon black is classified into furnace black, channel black, thermal black, etc. depending on the production method, and into acetylene black, ketjen black, oil black, gas black, etc. depending on the raw materials, but any of them can be used in the polyamide resin composition of the present embodiment without any particular limitation. (G) Carbon black may be used alone or in combination of two or more types.

[0121] The average primary particle size of the (G) carbon black is preferably close to the number-average particle size of the domains of the (B) crystalline semi-aromatic polyamide dispersed in the (A) crystalline aliphatic polyamide. Specifically, it is preferably 10 nm to 100 nm, more preferably 15 nm to 60 nm, even more preferably 15 nm to 50 nm, even more preferably 15 nm to 40 nm, and particularly preferably 15 nm to 30 nm. Having an average primary particle size within the above range can further improve the weather resistance and mechanical properties of a molded article. The average primary particle size is determined by taking an image of dispersed carbon black particles according to the procedure described in ASTM D3849 (Standard Test Method for Carbon Black - Morphological Characterization by Electron Microscopy), measuring the particle sizes of 3,000 unit constituent particles from this image, and averaging the measured values.

[0122] (G) The specific surface area of ​​carbon black is 50 m２ / g or more 300m ２ / g or less (BET adsorption method). When the specific surface area is within the above range, the low warpage, surface appearance, weather resistance, and gloss retention of the molded article can be further improved. The specific surface area of ​​(G) carbon black is a value measured from the nitrogen adsorption amount in accordance with JIS K6217.

[0123] The DBP oil absorption of (G) carbon black (the amount of dibutyl phthalate absorbed by 100 g of carbon black) is preferably 50 mL / 100 g or more and 150 mL / 100 g or less. Having the DBP oil absorption within this range allows for further improvements in low warpage, weather resistance, and gloss retention when molded into a molded article. The DBP oil absorption of (G) carbon black is a value measured in accordance with JIS K6221.

[0124] The content of (G) carbon black is preferably 0.02 to 3.0% by mass, more preferably 0.02 to 1.0% by mass, even more preferably 0.02 to 0.8% by mass, particularly preferably 0.03 to 0.1% by mass, and most preferably 0.03 to 0.06% by mass, relative to the total mass of the polyamide resin composition. By keeping the content of (G) carbon black within the above range, it is possible to further improve the weather resistance, mechanical properties, and vibration damping and noise suppression effects without impairing the appearance of the molded article.

[0125] [(H) Phosphorus-Based Flame Retardant] The (H) phosphorus-based flame retardant is not particularly limited as long as it is a flame retardant containing phosphorus but not a halogen element. Examples of the (H) phosphorus-based flame retardant include phosphate ester-based flame retardants, melamine polyphosphate-based flame retardants, phosphazene-based flame retardants, phosphinic acid-based flame retardants, and red phosphorus-based flame retardants. The (H) phosphorus-based flame retardants may be used alone or in combination of two or more. Among these, the (H) phosphorus-based flame retardant is preferably a phosphate ester-based flame retardant, melamine polyphosphate-based flame retardant, phosphazene-based flame retardant, or phosphinic acid-based flame retardant, and particularly preferably a phosphinic acid-based flame retardant.

[0126] Specifically, the phosphinic acid flame retardant may contain at least one phosphinic acid salt selected from the group consisting of a phosphinic acid salt represented by the following general formula (1) (hereinafter, may be abbreviated as "phosphinic acid salt (1)"), a diphosphinic acid salt represented by the following general formula (2) (hereinafter, may be abbreviated as "diphosphinic acid salt (2)"), and condensates thereof.

[0127]

[0128] (In general formula (1), R11 and R12 each independently represent an alkyl group having 1 to 6 carbon atoms or an aryl group having 6 to 10 carbon atoms. Mn11+ represents an n11-valent metal ion, where n11 is 2 or 3. M represents an element belonging to Group 2 or 15 of the periodic table, a transition element, zinc, or aluminum. A plurality of R11 and R12 may be the same or different. In general formula (2), R21 and R22 are each independently an alkyl group having 1 to 6 carbon atoms or an aryl group having 6 to 10 carbon atoms. Y21 is an alkylene group having 1 to 10 carbon atoms or an arylene group having 6 to 10 carbon atoms. M'm21+ is an m21-valent metal ion, and m21 is 2 or 3. M' is an element belonging to Group 2 or Group 15 of the periodic table, a transition element, zinc, or aluminum. n21 is an integer of 1 to 3. When n21 is 2 or 3, multiple R21, R22, and Y21 may be the same or different. x is 1 or 2. When x is 2, multiple M'm21+ may be the same or different. n21, x, and m21 are integers that satisfy the relationship 2 × n21 = m21 × x.

[0129] (R11, R12, R21, and R22) R11, R12, R21, and R22 are each independently an alkyl group having 1 to 6 carbon atoms or an aryl group having 6 to 10 carbon atoms. Since n11 is 2 or 3, there are multiple R11s and R12s, which may be the same or different. From the perspective of ease of production, it is preferable that R11 and R12 are the same. Furthermore, when n21 is 2 or 3, there are multiple R21s and R22s which may be the same or different, but from the perspective of ease of production, it is preferable that they are the same. The alkyl group may be chain-like or cyclic, but chain-like is preferred. The chain-like alkyl group may be linear or branched. Examples of linear alkyl groups include a methyl group, an ethyl group, an n-propyl group, an n-butyl group, an n-pentyl group, and an n-hexyl group. Examples of branched alkyl groups include 1-methylethyl, 1-methylpropyl, 2-methylpropyl, 1,1-dimethylethyl, 1-methylbutyl, 2-methylbutyl, 3-methylbutyl, 1,1-dimethylpropyl, 1,2-dimethylpropyl, 2,2-dimethylpropyl, 1-methylpentyl, 2-methylpentyl, 3-methylpentyl, 4-methylpentyl, 1,1-dimethylbutyl, 1,2-dimethylbutyl, 1,3-dimethylbutyl, 2,2-dimethylbutyl, 2,3-dimethylbutyl, 3,3-dimethylbutyl, 1-ethylbutyl, 2-ethylbutyl, and 1,1,2-trimethylpropyl groups. Examples of aryl groups include phenyl and naphthyl groups. The alkyl and aryl groups may have a substituent. Examples of the substituent in the alkyl group include aryl groups having 6 to 10 carbon atoms. Examples of the substituent in the aryl group include alkyl groups having 1 to 6 carbon atoms. Specific examples of the substituted alkyl group include a benzyl group, etc. Specific examples of the substituted aryl group include a tolyl group, a xylyl group, etc.Among these, R11, R12, R21 and R22 are preferably alkyl groups having 1 to 6 carbon atoms, and more preferably methyl or ethyl groups.

[0130] (Y21) Y21 is an alkylene group having 1 to 10 carbon atoms or an arylene group having 6 to 10 carbon atoms. When n21 is 2 or 3, multiple Y21 may be the same or different, but are preferably the same for ease of production. The alkylene group may be chain-like or cyclic, but is preferably chain-like. The chain-like alkylene group may be linear or branched. Examples of the chain-like alkylene group include a methylene group, an ethylene group, a trimethylene group, a tetramethylene group, a pentamethylene group, and a hexamethylene group. Examples of the branched alkylene group include a 1-methylethylene group and a 1-methylpropylene group. Examples of the arylene group include a phenylene group and a naphthylene group. The alkylene group and the arylene group may have a substituent. Examples of the substituent in the alkylene group include an aryl group having 6 to 10 carbon atoms. Examples of the substituent in the arylene group include an alkyl group having 1 to 6 carbon atoms. Specific examples of the alkylene group having a substituent include a phenylmethylene group, a phenylethylene group, a phenyltrimethylene group, and a phenyltetramethylene group. Specific examples of the arylene group having a substituent include a methylphenylene group, an ethylphenylene group, a tert-butylphenylene group, a methylnaphthylene group, an ethylnaphthylene group, and a tert-butylnaphthylene group. Of these, Y21 is preferably an alkylene group having 1 to 10 carbon atoms, and more preferably a methylene group or an ethylene group.

[0131] (M and M') M and M' are each independently an ion of an element belonging to Group 2 or Group 15 of the periodic table, an ion of a transition element, a zinc ion, or an aluminum ion. Examples of ions of elements belonging to Group 2 of the periodic table include calcium ions and magnesium ions. Examples of ions of elements belonging to Group 15 of the periodic table include bismuth ions. Furthermore, when x is 2, multiple M's may be the same or different, but are preferably the same for ease of production. Among these, calcium, zinc, or aluminum is preferred as M and M', and calcium or aluminum is more preferred.

[0132] (x) x represents the number of M' and is 1 or 2. x can be appropriately selected depending on the type of M' and the number of diphosphinic acids.

[0133] (n11 and n21) n11 represents the number of phosphinic acids and the valence of M, and is 2 or 3. n11 can be appropriately selected depending on the type and valence of M. n21 represents the number of diphosphinic acids and is an integer of 1 or more and 3 or less. n21 can be appropriately selected depending on the type and number of M'.

[0134] (m21) m21 represents the valence of M' and is 2 or 3. n21, x, and m21 are integers that satisfy the relational expression 2×n21=m21×x.

[0135] Specific examples of preferred phosphinates (1) include calcium dimethylphosphinate, magnesium dimethylphosphinate, aluminum dimethylphosphinate, zinc dimethylphosphinate, calcium ethylmethylphosphinate, magnesium ethylmethylphosphinate, aluminum ethylmethylphosphinate, zinc ethylmethylphosphinate, calcium diethylphosphinate, magnesium diethylphosphinate, aluminum diethylphosphinate, zinc diethylphosphinate, calcium methyl-n-propylphosphinate, magnesium methyl-n-propylphosphinate, aluminum methyl-n-propylphosphinate, zinc methyl-n-propylphosphinate, methanedi(methylphosphinate), ) calcium, magnesium methane di(methylphosphinate), aluminum methane di(methylphosphinate), zinc methane di(methylphosphinate), calcium benzene-1,4-(dimethylphosphinate), magnesium benzene-1,4-(dimethylphosphinate), aluminum benzene-1,4-(dimethylphosphinate), zinc benzene-1,4-(dimethylphosphinate), calcium methylphenylphosphinate, magnesium methylphenylphosphinate, aluminum methylphenylphosphinate, zinc methylphenylphosphinate, calcium diphenylphosphinate, magnesium diphenylphosphinate, aluminum diphenylphosphinate, zinc diphenylphosphinate, etc. Among these, calcium dimethylphosphinate or aluminum dimethylphosphinate is particularly preferred as the phosphinate (1) because of its excellent flame retardancy.

[0136] Specific examples of preferred diphosphinates (2) include calcium methane di(methylphosphinate), magnesium methane di(methylphosphinate), aluminum methane di(methylphosphinate), zinc methane di(methylphosphinate), calcium benzene-1,4-di(methylphosphinate), magnesium benzene-1,4-di(methylphosphinate), aluminum benzene-1,4-di(methylphosphinate), and zinc benzene-1,4-di(methylphosphinate).

[0137] The method for producing phosphinates is not particularly limited, but examples thereof include the methods described in JP 2005-179362 A, EP 699708 A, and JP 08-073720 A. Specifically, phosphinates are produced in an aqueous solution using phosphinic acid and a metal carbonate, metal hydroxide, or metal oxide. These are essentially monomeric compounds, but also include polymeric phosphinates that are condensates with a condensation degree of 1 to 3 depending on the reaction conditions and environment.

[0138] The content of the (H) phosphorus-based flame retardant is preferably 0.1 parts by mass or more and 30 parts by mass or less, more preferably 5 parts by mass or more and 30 parts by mass or less, even more preferably 10 parts by mass or more and 29 parts by mass or less, and particularly preferably 15 parts by mass or more and 29 parts by mass or less, relative to 100 parts by mass of the total mass of the (A) crystalline aliphatic polyamide and the (B) crystalline semi-aromatic polyamide. By setting the content of the (H) phosphorus-based flame retardant to the above-mentioned lower limit or more, a polyamide resin composition having excellent flame retardancy when molded into a molded product tends to be obtained. On the other hand, by setting the amount of the (H) phosphorus-based flame retardant to the above-mentioned upper limit or less, a polyamide resin composition having excellent flame retardancy when molded into a molded product tends to be obtained without impairing the properties of the polyamide.

[0139] [(I) Nucleating Agent] (I) Nucleating agent means a substance that, when added, provides at least one of the following effects (1) to (3): (1) The effect of increasing the crystallization peak temperature of the polyamide resin composition. (2) The effect of reducing the difference between the extrapolated onset temperature and the extrapolated end temperature of the crystallization peak. (3) The effect of minimizing or uniforming the size of spherulites in the resulting molded article.

[0140] Examples of (I) nucleating agents include, but are not limited to, boron nitride, silicon nitride, potassium titanate (excluding potassium titanate fiber), molybdenum disulfide, etc. One type of (I) nucleating agent may be used alone, or two or more types may be used in combination. Among these, boron nitride is preferred as (I) nucleating agent from the viewpoint of nucleating agent effect. In this specification, components that are both (C) inorganic filler and (I) nucleating agent are treated as (C) inorganic filler.

[0141] Furthermore, since the effect as a (I) nucleating agent is higher, the number average particle diameter of the (I) nucleating agent is preferably 0.01 μm or more and 10 μm or less. The number average particle diameter of the (I) nucleating agent can be determined using the following method. First, a polyamide resin composition or a molded product thereof is dissolved in a solvent in which polyamide is soluble, such as formic acid. Next, from the resulting insoluble components, for example, 100 or more nucleating agents are arbitrarily selected. Next, the particle diameters are measured by observation using an optical microscope, a scanning electron microscope, or the like, and the particle diameter can be determined by dividing the measured particle diameter by the number of nucleating agents.

[0142] The content of (I) nucleating agent in the polyamide resin composition of this embodiment is preferably 0.001% by mass or more and 1% by mass or less, more preferably 0.001% by mass or more and 0.5% by mass or less, and even more preferably 0.001% by mass or more and 0.09% by mass or less, relative to the total mass of the polyamide resin composition. (I) Nucleating Agent By setting the content of the nucleating agent to be equal to or greater than the above-mentioned lower limit, the heat resistance of the polyamide resin composition tends to be further improved. Furthermore, by setting the content of the (I) nucleating agent to be equal to or less than the above-mentioned upper limit, a polyamide resin composition with better toughness tends to be obtained.

[0143] [(J) Heat Stabilizer] Examples of the (J) heat stabilizer include, but are not limited to, phenol-based heat stabilizers, phosphorus-based heat stabilizers, amine-based heat stabilizers, metal salts of elements of Groups 3, 4, and 11 to 14 of the periodic table, and halides of alkali metals and alkaline earth metals.

[0144] (Phenol-Based Heat Stabilizer) Examples of phenol-based heat stabilizers include, but are not limited to, hindered phenol compounds, etc. Hindered phenol compounds have the property of imparting excellent heat resistance and light resistance to resins such as polyamides and fibers.

[0145] Examples of the hindered phenol compound include, but are not limited to, N,N'-hexane-1,6-diylbis[3-(3,5-di-tert-butyl-4-hydroxyphenylpropionamide], pentaerythrityl-tetrakis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], N,N'-hexamethylenebis(3,5-di-tert-butyl-4-hydroxy-hydrocinnamamide), triethylene glycol-bis[3-(3-tert-butyl-5-methyl-4-hydroxyphenyl)propionate], ester], 3,9-bis{2-[3-(3-tert-butyl-4-hydroxy-5-methylphenyl)propionyloxy]-1,1-dimethylethyl}-2,4,8,10-tetraoxaspiro[5,5]undecane, 3,5-di-tert-butyl-4-hydroxybenzylphosphonate-diethyl ester, 1,3,5-trimethyl-2,4,6-tris(3,5-di-tert-butyl-4-hydroxybenzyl)benzene, 1,3,5-tris(4-tert-butyl-3-hydroxy-2,6-dimethylbenzyl)isocyanuric acid, etc. These hindered phenol compounds may be used alone or in combination of two or more. In particular, from the viewpoint of improving heat aging resistance, N,N'-hexane-1,6-diylbis[3-(3,5-di-tert-butyl-4-hydroxyphenylpropionamide)] is preferred as the hindered phenol compound.

[0146] When a phenolic heat stabilizer is used, the content of the phenolic heat stabilizer in the polyamide resin composition is preferably 0.01% by mass or more and 1% by mass or less, and more preferably 0.1% by mass or more and 1% by mass or less, relative to the total mass of the polyamide resin composition. When the content of the phenolic heat stabilizer is within the above range, the heat aging resistance of the polyamide resin composition can be further improved and the amount of gas generation can be further reduced.

[0147] (Phosphorus-Based Heat Stabilizer) Examples of phosphorus-based heat stabilizers include, but are not limited to, pentaerythritol-type phosphite compounds, trioctyl phosphite, trilauryl phosphite, tridecyl phosphite, octyl diphenyl phosphite, trisisodecyl phosphite, phenyl diisodecyl phosphite, phenyl di(tridecyl) phosphite, diphenyl isooctyl phosphite, diphenyl isodecyl phosphite, diphenyl (tridecyl) phosphite, triphenyl phosphite, tris(nonyl) phosphite, tris(2,4-di-tert-butylphenyl)phosphite, tris(2,4-di-tert-butyl-5-methylphenyl)phosphite, tris(butoxyethyl)phosphite, 4,4'-butylidene-bis(3-methyl-6-tert-butylphenyl-tetra-tridecyl)diphosphite, tetra(C12-C15 mixed alkyl)-4,4'-isopropylidenediphenyldiphosphite, 4,4'-isopropylidenebis(2-tert-butylphenyl)-di(no tris(biphenyl)phosphite, tetra(tridecyl)-1,1,3-tris(2-methyl-5-tert-butyl-4-hydroxyphenyl)butane diphosphite, tetra(tridecyl)-4,4'-butylidenebis(3-methyl-6-tert-butylphenyl)diphosphite, tetra(C1-C15 mixed alkyl)-4,4'-isopropylidenediphenyl diphosphite, tris(mono- and di-mixed nonylphenyl)phosphite, 4,4'-isopropylidenebis(2 -tert-butylphenyl)-di(nonylphenyl)phosphite, 9,10-di-hydro-9-oxa-9-oxa-10-phosphaphenanthrene-10-oxide, tris(3,5-di-tert-butyl-4-hydroxyphenyl)phosphite, hydrogenated-4,4'-isopropylidene diphenyl polyphosphite, bis(octylphenyl)-bis(4,4'-butylidenebis(3-methyl-6-tert-butylphenyl))-1,6-hexanol diphosphite, hexatridecyl-1,1,Examples of such phosphorus-based heat stabilizers include 3-tris(2-methyl-4-hydroxy-5-tert-butylphenyl)diphosphite, tris(4,4'-isopropylidenebis(2-tert-butylphenyl))phosphite, tris(1,3-stearoyloxyisopropyl)phosphite, 2,2-methylenebis(4,6-di-tert-butylphenyl)octyl phosphite, 2,2-methylenebis(3-methyl-4,6-di-tert-butylphenyl)2-ethylhexyl phosphite, tetrakis(2,4-di-tert-butyl-5-methylphenyl)-4,4'-biphenylene diphosphite, and tetrakis(2,4-di-tert-butylphenyl)-4,4'-biphenylene diphosphite. These phosphorus-based heat stabilizers may be used alone or in combination of two or more. Among these, from the viewpoint of further improving the heat aging resistance of the polyamide resin composition and reducing the amount of gas generated, the phosphorus-based heat stabilizer is preferably at least one selected from the group consisting of pentaerythritol-type phosphite compounds and tris(2,4-di-tert-butylphenyl)phosphite.

[0148] Examples of the pentaerythritol phosphite compound include, but are not limited to, 2,6-di-tert-butyl-4-methylphenyl-phenyl-pentaerythritol diphosphite, 2,6-di-tert-butyl-4-methylphenyl-methyl-pentaerythritol diphosphite, 2,6-di-tert-butyl-4-methylphenyl-2-ethylhexyl-pentaerythritol diphosphite, 2,6-di-tert-butyl-4-methylphenyl-isodecyl-pentaerythritol diphosphite, 2,6-di-tert-butyl-4-methylphenyl-isodecyl-pentaerythritol diphosphite, 6-di-tert-butyl-4-methylphenyl-lauryl-pentaerythritol diphosphite, 2,6-di-tert-butyl-4-methylphenyl-isotridecyl-pentaerythritol diphosphite, 2,6-di-tert-butyl-4-methylphenyl-stearyl pentaerythritol diphosphite, 2,6-di-tert-butyl-4-methylphenyl-cyclohexyl-pentaerythritol diphosphite, 2,6-di-tert-butyl-4-methylphenyl-benzyl-pentaerythritol diphosphite, 2,6-di-tert-butyl-4-methylphenyl ethyl cellosolve-pentaerythritol diphosphite, 2,6-di-tert-butyl-4-methylphenyl-butylcarbitol-pentaerythritol diphosphite, 2,6-di-tert-butyl-4-methylphenyl-octylphenyl-pentaerythritol diphosphite, 2,6-di-tert-butyl-4-methylphenyl-nonylphenyl pentaerythritol diphosphite, bis(2,6-di-tert-butyl-4-methylphenyl)pentaerythritol diphosphite, bis(2,6-di-tert-butyl-4-ethylphenyl)pentaerythritol diphosphite, 2,6-di-tert-butyl-4-methylphenyl-2,6-di-tert-butylphenyl-pentaerythritol diphosphite, 2,6-di-tert-butyl-4-methylphenyl-2,4-di-tert-butylphenyl-pentaerythritol diphosphite, 2,6-di-tert-butyl-4-methylphenyl-2,4-di-tert-octylphenyl-pentaerythritol diphosphite, 2,Examples of such pentaerythritol phosphite compounds include 6-di-tert-butyl-4-methylphenyl-2-cyclohexylphenyl-pentaerythritol diphosphite, 2,6-di-tert-amyl-4-methylphenyl-phenyl pentaerythritol diphosphite, bis(2,6-di-tert-amyl-4-methylphenyl)pentaerythritol diphosphite, and bis(2,6-di-tert-octyl-4-methylphenyl)pentaerythritol diphosphite. These pentaerythritol phosphite compounds may be used alone or in combination of two or more. Among these, from the viewpoint of reducing the amount of gas generated from the polyamide resin composition, the pentaerythritol phosphite compound is preferably one or more selected from the group consisting of bis(2,6-di-tert-butyl-4-methylphenyl)pentaerythritol diphosphite, bis(2,6-di-tert-butyl-4-ethylphenyl)pentaerythritol diphosphite, bis(2,6-di-tert-amyl-4-methylphenyl)pentaerythritol diphosphite, and bis(2,6-di-tert-octyl-4-methylphenyl)pentaerythritol diphosphite, with bis(2,6-di-tert-butyl-4-methylphenyl)pentaerythritol diphosphite being more preferred.

[0149] When a phosphorus-based heat stabilizer is used, the content of the phosphorus-based heat stabilizer in the polyamide resin composition is preferably 0.01% by mass or more and 1% by mass or less, and more preferably 0.1% by mass or more and 1% by mass or less, relative to the total mass of the polyamide resin composition. When the content of the phosphorus-based heat stabilizer is within the above range, the heat aging resistance of the polyamide resin composition can be further improved and the amount of gas generation can be further reduced.

[0150] (Amine-Based Heat Stabilizer) Examples of the amine-based heat stabilizer include, but are not limited to, 4-acetoxy-2,2,6,6-tetramethylpiperidine, 4-stearoyloxy-2,2,6,6-tetramethylpiperidine, 4-acryloyloxy-2,2,6,6-tetramethylpiperidine, 4-(phenylacetoxy)-2,2,6,6-tetramethylpiperidine, 4-benzoyloxy-2,2,6,6-tetramethylpiperidine, 4-methoxy-2,2,6,6-tetramethylpiperidine, and 4-stearyloxy-2,2,6,6-tetramethylpiperidin. 4-cyclohexyloxy-2,2,6,6-tetramethylpiperidine, 4-benzyloxy-2,2,6,6-tetramethylpiperidine, 4-phenoxy-2,2,6,6-tetramethylpiperidine, 4-(ethylcarbamoyloxy)-2,2,6,6-tetramethylpiperidine, 4-(cyclohexylcarbamoyloxy)-2,2,6,6-tetramethylpiperidine, 4-(phenylcarbamoyloxy)-2,2,6,6-tetramethylpiperidine, bis(2,2,6,6-tetramethyl-4-piperidyl)-carbonate, bis( 2,2,6,6-tetramethyl-4-piperidyl)-oxalate, bis(2,2,6,6-tetramethyl-4-piperidyl)-malonate, bis(2,2,6,6-tetramethyl-4-piperidyl)-sebacate, bis(2,2,6,6-tetramethyl-4-piperidyl)-adipate, bis(2,2,6,6-tetramethyl-4-piperidyl)-terephthalate, 1,2-bis(2,2,6,6-tetramethyl-4-piperidyloxy)-ethane, α,α'-bis(2,2,6,6-tetramethyl-4-piperidyloxy)-p-xylene, biphenyl bis(2,2,6,6-tetramethyl-4-piperidyl)tolylene-2,4-dicarbamate, bis(2,2,6,6-tetramethyl-4-piperidyl)hexamethylene-1,6-dicarbamate, tris(2,2,6,6-tetramethyl-4-piperidyl)benzene-1,3,5-tricarboxylate, tris(2,2,6,6-tetramethyl-4-piperidyl)benzene-1,3,4-tricarboxylate, 1-[2-{3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionyloxy}butyl]-4-[3-(3,[5-di-tert-butyl-4-hydroxyphenyl)propionyloxy]2,2,6,6-tetramethylpiperidine, a condensate of 1,2,3,4-butanetetracarboxylic acid, 1,2,2,6,6-pentamethyl-4-piperidinol, and β,β,β',β'-tetramethyl-3,9-[2,4,8,10-tetraoxaspiro(5,5)undecane]diethanol, and the like. These amine-based heat stabilizers may be used alone or in combination of two or more.

[0151] When an amine-based heat stabilizer is used, the content of the amine-based heat stabilizer in the polyamide resin composition is preferably 0.01% by mass or more and 1% by mass or less, and more preferably 0.1% by mass or more and 1% by mass or less, relative to the total mass of the polyamide resin composition. When the content of the amine-based heat stabilizer is within the above range, the heat aging resistance of the obtained molded article can be further improved, and the amount of gas generation can be further reduced.

[0152] (Metal Salts of Elements in Groups 3, 4, and 11-14 of the Periodic Table) There are no particular limitations on the metal salts of elements in Groups 3, 4, and 11-14 of the Periodic Table, as long as they are salts of metals belonging to these groups. Among these, copper salts are preferred from the viewpoint of further improving the heat aging resistance of the resulting molded article. Examples of such copper salts include, but are not limited to, copper halides, copper acetate, copper propionate, copper benzoate, copper adipate, copper terephthalate, copper isophthalate, copper salicylate, copper nicotinate, copper stearate, and copper complex salts in which copper is coordinated with a chelating agent. Examples of copper halides include copper iodide, copper (I) bromide, copper (II) bromide, and copper (I) chloride. Examples of chelating agents include ethylenediamine and ethylenediaminetetraacetic acid. These copper salts may be used alone or in combination of two or more. Among them, the copper salt is preferably at least one selected from the group consisting of copper iodide, copper (I) bromide, copper (II) bromide, copper (I) chloride, and copper acetate, and more preferably at least one selected from the group consisting of copper iodide and copper acetate. When the above-mentioned preferred copper salts are used, a polyamide resin composition tends to be obtained which is more excellent in heat aging resistance and can more effectively suppress metal corrosion of the screw and cylinder during extrusion (hereinafter, sometimes simply referred to as "metal corrosion").

[0153] When a copper salt is used as the heat stabilizer (J), the content of the copper salt in the polyamide resin composition is preferably 0.01 to 0.60 parts by mass, more preferably 0.02 to 0.40 parts by mass, per 100 parts by mass of the total of the crystalline aliphatic polyamide (A) and the crystalline semi-aromatic polyamide (B). When the copper salt content is within the above range, the heat aging resistance of the polyamide resin composition tends to be further improved, and copper precipitation and metal corrosion tend to be more effectively suppressed.

[0154] In addition, from the viewpoint of improving the heat aging resistance of the polyamide resin composition, the content concentration of copper element derived from the copper salt is set to 10% by weight of the total of (A) crystalline aliphatic polyamide and (B) crystalline semi-aromatic polyamide. ６The amount is preferably 10 parts by mass or more and 2000 parts by mass or less, more preferably 30 parts by mass or more and 1500 parts by mass or less, and even more preferably 50 parts by mass or more and 500 parts by mass or less, per 1 million parts by mass.

[0155] (Alkali Metal and Alkaline Earth Metal Halides) Examples of alkali metal and alkaline earth metal halides include, but are not limited to, potassium iodide, potassium bromide, potassium chloride, sodium iodide, sodium chloride, etc. These alkali metal and alkaline earth metal halides may be used alone or in combination of two or more. Among these, from the viewpoints of improving heat aging resistance and suppressing metal corrosion, the alkali metal and alkaline earth metal halides are preferably one or more selected from the group consisting of potassium iodide and potassium bromide, and more preferably potassium iodide.

[0156] When alkali metal and alkaline earth metal halides are used, the content of the alkali metal and alkaline earth metal halides in the polyamide resin composition is preferably 0.05 to 20 parts by mass, more preferably 0.2 to 10 parts by mass, per 100 parts by mass of the total of (A) the crystalline aliphatic polyamide and (B) the crystalline semi-aromatic polyamide. When the content of the alkali metal and alkaline earth metal halides is within the above range, the heat aging resistance of the obtained molded article is further improved, and copper precipitation and metal corrosion can be more effectively suppressed.

[0157] The components of the heat stabilizer (J) described above may be used alone or in combination of two or more. Among them, a mixture of a copper salt and a halide of an alkali metal and an alkaline earth metal is preferred as the heat stabilizer (J) from the viewpoint of further improving the heat aging resistance of the resulting molded article.

[0158] The content ratio of the copper salt and the alkali metal and alkaline earth metal halides is preferably 2 / 1 or more and 40 / 1 or less, more preferably 5 / 1 or more and 30 / 1 or less, in terms of the molar ratio of halogen to copper (halogen / copper). When the molar ratio of halogen to copper (halogen / copper) is within the above range, the heat aging resistance of the obtained molded body tends to be further improved. Furthermore, when the molar ratio of halogen to copper (halogen / copper) is equal to or more than the above lower limit, copper precipitation and metal corrosion tend to be more effectively suppressed. On the other hand, when the molar ratio of halogen to copper (halogen / copper) is equal to or less than the above upper limit, corrosion of the screw of the molding machine tends to be more effectively prevented without substantially impairing the mechanical properties (toughness, etc.) of the molded body.

[0159] [(K) Other Polymers] The polyamide resin composition of this embodiment may contain (K) other polymers to the extent that the effects of the present invention are not impaired. Examples of (K) other polymers include aromatic polyamides other than (B) crystalline semi-aromatic polyamide, polyesters, liquid crystal polyesters, polyphenylene sulfides, polyphenylene ethers, polycarbonates, polyarylates, phenolic resins, epoxy resins, acrylic resins, polyolefin resins, etc. Also included are copolymers of these (K) other polymers with polyamide resins.

[0160] (Aromatic polyamides other than the above (B) crystalline semi-aromatic polyamide) Examples of aromatic polyamides other than the above (B) crystalline semi-aromatic polyamide include, but are not limited to, polyamide 4T, 4T / 6T, 4T / 2Me5T, 4T / 6T / 66, 4T / 6T / 46, 4T / 6T / 2Me5T, 5T, 6T / 2Me5T, 6T / 6I, 8T, 9T, 10T, 6I, 6I / 6T, 66 / 6T, etc. PA6I is considered a material suitable for decorative parts because of its excellent moldability and the appearance of the molded product.

[0161] The content of the (K) other polymer is preferably 0% by mass or more and 3% by mass or less, more preferably 0% by mass or more and 2% by mass or less, and even more preferably 0% by mass or more and 1% by mass or less, relative to 100% by mass of all resin components in the polyamide resin composition.

[0162] [(L) Other Additives] In addition to the above-described components, the polyamide resin composition of the present embodiment may contain (L) other additives commonly used in polyamide resin compositions, provided that the effects of the present invention are not impaired. Examples of (L) other additives include colorants such as pigments and dyes (including colored masterbatches), flame retardants other than phosphorus-based flame retardants (H), fibrillating agents, fluorescent bleaching agents, plasticizers, antioxidants, ultraviolet absorbers, antistatic agents, flow improvers, and spreading agents. When the polyamide resin composition of the present embodiment contains other additives, the content of (L) other additives varies depending on the type of additive and the intended use of the polyamide resin composition, and is not particularly limited as long as the effects of the present invention are not impaired.

[0163] <Method for producing polyamide resin composition> The method for producing the polyamide resin composition of this embodiment is not particularly limited as long as it includes a step of melt-kneading raw material components containing (A) a crystalline aliphatic polyamide and (B) a crystalline semi-aromatic polyamide. For example, a method including a step of melt-kneading raw material components containing (A) a crystalline aliphatic polyamide and (B) a crystalline semi-aromatic polyamide in an extruder, in which the set temperature of the extruder is not more than the melting point TmB2 + 50°C of the above-mentioned crystalline semi-aromatic polyamide (B), is preferred.

[0164] Examples of methods for melt-kneading raw material components containing (A) crystalline aliphatic polyamide and (B) crystalline semi-aromatic polyamide include a method in which (A) crystalline aliphatic polyamide and (B) crystalline semi-aromatic polyamide are mixed with other raw materials using a tumbler, Henschel mixer, etc., and then fed into a melt kneader for kneading; and a method in which (A) crystalline aliphatic polyamide and (B) crystalline semi-aromatic polyamide are melted in a single-screw or twin-screw extruder, and then other raw materials are blended from a side feeder.

[0165] 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 component from a different supply port.

[0166] The melt-kneading temperature is preferably about 250° C. or more and 375° C. or less in terms of resin temperature. The melt-kneading time is preferably about 0.25 minutes or more and 5 minutes or less. The apparatus for performing the melt-kneading is not particularly limited, and for example, a known melt-kneader such as a single-screw or twin-screw extruder, a Banbury mixer, or a mixing roll can be used.

[0167] In order to obtain a suitable number average particle size of the domains of the crystalline semi-aromatic polyamide (B) dispersed in the crystalline aliphatic polyamide (A), it is necessary to apply appropriate shear during kneading without generating large amounts of heat. As the melt kneader, it is preferable to use a co-rotating twin-screw extruder with a screw diameter of 30 mm or more. In addition, in the twin-screw extruder, the L / D is preferably 35 or more. In order to efficiently knead the twin-screw extruder, the screw rotation speed (N) is preferably 300 rpm or more, and the ratio Q / N of the screw rotation speed (N) to the discharge rate (Q) is preferably 0.5 or more. In addition, when adding the inorganic filler (C), since the inorganic filler (C) improves the kneading efficiency, it is preferable to dry-blend the crystalline aliphatic polyamide (A) and the crystalline semi-aromatic polyamide (B), and then feed them from the upstream feed port of the twin-screw extruder, and feed the inorganic filler (C) from the downstream feed port of the twin-screw extruder.

[0168] <Characteristics of Polyamide Resin Composition> The molecular weight, molecular weight distribution, and tan δ peak temperature of the polyamide resin composition of the present embodiment can be configured as follows, and can be measured by the method described in the examples below.

[0169] [Molecular Weight of Polyamide Resin Composition] The weight average molecular weight (Mw) can be used as an index of the molecular weight of a polyamide resin composition. The weight average molecular weight (Mw) of the polyamide resin composition is preferably 20,000 to 40,000, more preferably 22,000 to 35,000, even more preferably 25,000 to 33,000, and even more preferably 26,000 to 32,000. When the weight average molecular weight (Mw) is within the above range, the polyamide resin composition tends to have excellent mechanical properties when molded, particularly excellent mechanical strength under hot and humid heat conditions, and excellent impact resistance under low-temperature conditions. Furthermore, when a component such as (C) an inorganic filler is further contained, the polyamide resin composition tends to have excellent surface appearance. As a method for controlling the Mw of the polyamide resin composition within the above range, for example, (A) a crystalline aliphatic polyamide and (B) a crystalline semi-aromatic polyamide each having a weight average molecular weight (Mw(A)) within the above range can be used. Mw can be measured using GPC.

[0170] [Molecular Weight Distribution of Polyamide Resin Composition] The molecular weight distribution of the polyamide resin composition of this embodiment is indicated by the weight average molecular weight (Mw) / number average molecular weight (Mn). The lower limit of the weight average molecular weight (Mw) / number average molecular weight (Mn) of the polyamide resin composition of this embodiment is preferably 1.0, more preferably 1.2, even more preferably 1.5, even more preferably 1.8, particularly preferably 1.9, and most preferably 2.0. On the other hand, the upper limit of the Mw / Mn of the polyamide resin composition of this embodiment is preferably 3.5, more preferably 3.0, even more preferably 2.6, even more preferably 2.4, particularly preferably 2.2, and most preferably 2.1. That is, the Mw / Mn of the polyamide resin composition of this embodiment is preferably 1.0 to 3.5, more preferably 1.2 to 3.0, even more preferably 1.5 to 2.6, even more preferably 1.8 to 2.4, particularly preferably 1.9 to 2.2, and most preferably 2.0 to 2.1. Having an Mw / Mn ratio within the above range tends to result in a polyamide resin composition that is superior in impact resistance and fluidity under low-temperature conditions. Furthermore, when a component typified by (C) an inorganic filler is further contained, molded articles obtained from the polyamide resin composition tend to have superior surface appearance. Examples of methods for controlling the weight-average molecular weight (Mw) / number-average molecular weight (Mn) of the polyamide resin composition within the above range include a method for controlling the weight-average molecular weight (Mw(B)) / number-average molecular weight (Mn(B)) of the (B) crystalline semi-aromatic polyamide within the above range. When the molecular structure of a polyamide resin composition contains an aromatic compound unit, the molecular weight distribution (Mw / Mn) tends to increase as the molecular weight increases. By keeping the molecular weight distribution within the above range, the proportion of polyamide molecules having a three-dimensional molecular structure can be reduced, which can more effectively prevent the molecules from becoming three-dimensional during high-temperature processing and tends to maintain better fluidity. As a result, when a component typified by (C) an inorganic filler is further added, the surface appearance of a molded article obtained from the polyamide resin composition tends to be improved.

[0171] [Tan δ Peak Temperature of Polyamide Resin Composition] The lower limit of the tan δ peak temperature of the polyamide resin composition of this embodiment is preferably 90°C, more preferably 95°C, even more preferably 100°C, and even more preferably 105°C. On the other hand, the upper limit of the tan δ peak temperature of the polyamide resin composition is preferably 150°C, more preferably 140°C, and even more preferably 130°C. That is, the tan δ peak temperature of the polyamide resin composition is preferably 90°C or higher, more preferably 95°C or higher and 150°C or lower, even more preferably 100°C or higher and 140°C or lower, and even more preferably 105°C or higher and 130°C or lower. When the tan δ peak temperature of the polyamide resin composition of this embodiment is equal to or higher than the above lower limit, the polyamide resin composition tends to have better mechanical properties when molded into a molded article, particularly better mechanical strength in hot and wet heat conditions, flowability, and dielectric breakdown resistance. On the other hand, when the polyamide resin composition has a tan δ peak temperature of not more than the above upper limit, when a component such as (C) an inorganic filler is further contained, the molded article obtained from the polyamide resin composition tends to have better impact resistance under low temperature conditions, etc. The tan δ peak temperature of the polyamide resin composition can be measured, for example, using a viscoelasticity measurement analyzer (DVE-V4 manufactured by Rheology Co., Ltd.), and specifically, can be measured by the method described in the examples below.

[0172] [Heat Resistance of Polyamide Resin Composition] The area of ​​the melting peak above 150 ° C. (ΔHM1) can be used as an index of the heat resistance of the polyamide resin composition of this embodiment. The ratio of the area of ​​the melting peak above 150 ° C. (ΔHM1) to the total area of ​​all melting peaks (ΔHM) in the polyamide resin composition is preferably 95% to 100%, more preferably 97% to 100%, even more preferably 98% to 100%, and even more preferably 100%. When the ratio of the area of ​​the melting peak above 150 ° C. (ΔHM1) to the total area of ​​all melting peaks (ΔHM) in the polyamide resin composition is within the above range, the polyamide resin composition tends to have better mechanical properties when molded, particularly better mechanical strength under hot and wet heat conditions, and better impact resistance under low-temperature conditions. Furthermore, when a component typified by (C) an inorganic filler is further contained, the polyamide resin composition tends to have better surface appearance. Furthermore, the greater the content of the low-melting point component, the more the properties in the usage environment, particularly the mechanical strength under hot and wet heat conditions, and the electrical insulation properties at high temperatures, tend to deteriorate. Examples of a method for controlling the ratio of the area of ​​the melting peak above 150°C (ΔHM1) to the total area of ​​all melting peaks (ΔHM) in the polyamide resin composition within the above range include adjusting the content of the (K) other polymer within the above range. The melting peak of the polyamide resin composition can be measured using a measuring device such as a Diamond-DSC manufactured by Perkin-Elmer, and specifically, can be measured by the method described in the Examples below.

[0173] The storage modulus can also be used as an index of the heat resistance of the polyamide resin composition of this embodiment. The ratio (E'-2 / E'-1) of the storage modulus E'-2 at 120°C to the storage modulus E'-1 at 23°C of the polyamide resin composition is preferably 0.40 or more, more preferably 0.43 or more, even more preferably 0.45 or more, and even more preferably 0.50 or more. When the ratio (E'-2 / E'-1) of the storage modulus E'-2 at 120°C to the storage modulus E'-1 at 23°C of the polyamide resin composition is within the above range, a polyamide resin composition tends to be obtained that, when molded, has excellent mechanical properties, particularly excellent mechanical strength under hot and wet heat conditions, tracking resistance, and dielectric breakdown resistance under high-temperature conditions. Methods for controlling the ratio (E'-2 / E'-1) of the storage modulus E'-2 at 120°C to the storage modulus E'-1 at 23°C of a polyamide resin composition within the above range include using a polyamide resin composition in which the C / N ratio of the (B) crystalline semi-aromatic polyamide, the weight average molecular weight (Mw(A)) of the (A) crystalline aliphatic polyamide, and the weight average molecular weight (Mw(B)) of the (B) crystalline semi-aromatic polyamide are each within the above ranges. This tends to result in adequate compatibility between the (A) crystalline aliphatic polyamide and the (B) crystalline semi-aromatic polyamide, resulting in entanglement of the polymer chains, which in turn tends to improve the mechanical properties of the molded article, particularly the mechanical strength under hot and wet heat conditions, tracking resistance, and dielectric breakdown resistance under high temperature conditions. The storage modulus of the polyamide resin composition can be measured, for example, using a viscoelasticity measurement analyzer (DVE-V4 manufactured by Rheology Co., Ltd.) or the like, specifically, by the method described in the Examples below.

[0174] <Uses> The polyamide resin composition of the present embodiment has excellent mechanical properties, particularly excellent mechanical strength under hot and wet heat conditions, dielectric breakdown resistance, and impact resistance under low-temperature conditions, and is therefore suitable for use in molded articles for applications in ambient temperature environments, including cold regions. Examples include electrical and / or electronic components such as connectors, motor magnet fastening parts, and solar power generation module cases, automotive components such as intake system parts, cooling system parts, fuel system parts, interior parts, exterior parts, and electrical components, mobile device parts, industrial device parts, daily necessities and household goods, and extruded products.

[0175] Examples of automotive intake system parts include, but are not limited to, air intake manifolds, intercooler inlets, exhaust pipe covers, inner bushings, bearing retainers, engine mounts, engine head covers, resonators, throttle bodies, etc. Examples of automotive cooling system parts include, but are not limited to, chain covers, thermostat housings, outlet pipes, radiator tanks, alternators, delivery pipes, etc. Examples of automotive fuel system parts include, but are not limited to, fuel delivery pipes, gasoline tank cases, etc. Examples of automotive interior parts include, but are not limited to, instrument panels, console boxes, glove boxes, steering wheels, trim, etc. Examples of automotive exterior parts include, but are not limited to, moldings, lamp housings, lamp adjusters, front grilles, mudguards, side bumpers, door mirror stays, roof rails, etc. Examples of automotive electrical components include, but are not limited to, connectors, wire harness connectors, motor components, motor covers, motor housings, motor insulators, resolvers, motor magnet retaining components, lamp sockets, sensor-mounted switches, and combination switches.

[0176] <Molded Article> The molded article of this embodiment contains the polyamide resin composition of this embodiment described above and is obtained by molding the polyamide resin composition. Furthermore, the molded article of this embodiment has a high surface gloss value. The surface gloss value of the molded article of this embodiment is preferably 50 or more, more preferably 65 or more, and even more preferably 70 or more. When the surface gloss value of the molded article is equal to or greater than the above-mentioned lower limit, the obtained molded article can be suitably used not only for automobiles but also for various parts such as electrical and electronic parts, home appliance parts, OA (Office Automation) equipment parts, mobile device parts, industrial equipment parts, daily necessities and household goods, as well as for extrusion product applications. In particular, the molded article of this embodiment, which has excellent surface appearance, is suitably used as automotive parts, electrical and electronic parts, home appliance parts, OA equipment parts, or mobile device parts.

[0177] The method for producing the molded body is not particularly limited, and any known molding method can be used, including, but not limited to, commonly known plastic molding methods such as press molding, injection molding, gas-assisted injection molding, welding molding, extrusion molding, blow molding, film molding, blow molding, multi-layer molding, and melt spinning.

[0178] The molded article of this embodiment has excellent mechanical properties, particularly excellent mechanical strength under hot and wet heat conditions, dielectric breakdown resistance, and impact resistance under low-temperature conditions, and therefore can be suitably used as parts in the electric vehicle field, i.e., hybrid vehicles (HVs), plug-in hybrid vehicles (PHVs), electric vehicles (EVs), fuel cell vehicles (FCVs), etc., which are equipped with lithium-ion secondary batteries and use electric motors as power sources. Examples of such parts include cases for housing motor mounts, power modules, converters, capacitors, insulators, motor terminal blocks, batteries, electric compressors, battery current sensors, junction blocks, etc., and in particular ignition coil cases for distributorless ignition (DLI) systems.

[0179] The electric and electronic components are not particularly limited, but examples thereof include connectors, reflectors for light emitting devices, switches, relays, printed wiring boards, housings for electronic components, outlets, noise filters, coil bobbins, motor end caps, etc. Reflectors for light emitting devices can be widely used for semiconductor packages such as light emitting diodes (LEDs), optical semiconductors such as laser diodes (LDs), photodiodes, charge coupled devices (CCDs), complementary metal oxide semiconductors (CMOS), etc.

[0180] Examples of portable device parts include, but are not limited to, housings and structures of mobile phones, smartphones, personal computers, portable game devices, digital cameras, and the like.

[0181] Industrial equipment parts are not particularly limited, but examples thereof include gears, cams, insulating blocks, valves, power tool parts, agricultural equipment parts, engine covers, and the like.

[0182] Examples of daily commodities and household goods include, but are not limited to, buttons, food containers, office furniture, and the like.

[0183] The uses of the extruded products are not particularly limited, but examples thereof include films, sheets, filaments, tubes, rods, and hollow molded articles.

[0184] Furthermore, since the molded article according to a certain aspect of this embodiment has excellent surface appearance, it is also preferably used as a molded article having a coating film formed on the surface of the molded article. The method for forming the coating film is not particularly limited as long as it is a known method, and can be, for example, a spray method, an electrostatic coating method, or the like. The paint used for painting is not particularly limited as long as it is a known method, and can be, for example, a melamine crosslinked polyester polyol resin paint, an acrylic urethane paint, or the like.

[0185] The molded article of one aspect of this embodiment is suitable as a material for automobile parts, among the above, because it has excellent mechanical strength, toughness, heat resistance, and vibration fatigue resistance, and furthermore, because it has excellent sliding properties, it is particularly suitable as a material for gears and bearings. Furthermore, the molded article of one aspect of this embodiment is suitable as a material for electrical and electronic parts, because it has excellent mechanical strength, toughness, and heat resistance.

[0186] 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. First, the measurement methods, evaluation methods, and raw materials used in the examples and comparative examples are shown below. In the examples, the pressure of 1 kg / cm ２ means 0.098 MPa.

[0187] <Constituent Components> [(A) Crystalline Aliphatic Polyamide] A-1: ​​Polyamide 66 (Mw(A) = 35,000, Mw(A) / Mn(A) = 2.0, TmA2 = 265°C, crystallization enthalpy ΔH = 68 J / g, tan δ peak temperature = 80°C) A-2: Polyamide 66 (Mw(A) = 40,000, Mw(A) / Mn(A) = 2.0, TmA2 = 265°C, crystallization enthalpy ΔH = 65 J / g, tan δ peak temperature = 80°C) A-3: Polyamide 66 (Mw(A) = 30,000, Mw(A) / Mn(A) = 2.0, TmA2 = 265°C, crystallization enthalpy ΔH = 70 J / g, tan δ peak temperature = 80°C)

[0188] [(B) Crystalline Semi-Aromatic Polyamide] B-1: Polyamide 4T / 6T (Mw(B) = 18,000, Mw(B) / Mn(B) = 2.1, TmB2 = 335°C, crystallization enthalpy ΔH = 52 J / g, tan δ peak temperature = 160°C, C / N ratio = 6.60, ratio of terephthalic acid units in all dicarboxylic acid units was 100 mol%) B-2: Polyamide 4T / 6T / 66 (Mw(B) = 20,000, Mw(B) / Mn(B) = 2.2, TmB2 = 325°C, crystallization enthalpy ΔH = 54 J / g, tan δ peak temperature = 125°C, C / N ratio = 6.01, ratio of terephthalic acid units in all dicarboxylic acid units was 85 mol%) B-3: Polyamide 6T / 6I ("Arlen A3000" (Mitsui Chemicals, Inc.), Mw (B) = 29,000, Mw (B) / Mn (B) = 3.2, TmB2 = 320 ° C, crystallization enthalpy ΔH = 37 J / g, tan δ peak temperature = 130 ° C, C / N ratio = 7.00, the ratio of terephthalic acid units in all dicarboxylic acid units is 70 mol%) B-4: Polyamide 9T ("Genesta N1000A" (Kuraray Co., Ltd.), Mw (B) = 29,000, Mw (B) / Mn (B) = 3.1, TmB2 = 305 ° C, crystallization enthalpy ΔH = 44 J / g, tan δ peak temperature = 120 ° C, C / N ratio = 8.50, the ratio of terephthalic acid units in all dicarboxylic acid units is 100 mol%)

[0189] [(C) Inorganic Filler] C-1: Glass fiber (GF) (manufactured by Nippon Electric Glass Co., Ltd., product name "ECS03T275H", number average fiber diameter (average particle diameter): 10 μm (circular), cut length: 3 mm) The average fiber diameter of the glass fiber was measured as follows. First, the polyamide resin composition was placed in an electric furnace, and organic matter contained in the polyamide resin composition was incinerated. The cross sections of 100 or more glass fibers randomly selected from the residue after the incineration were observed with a scanning electron microscope (SEM), and the fiber diameters of these glass fibers were measured to determine the number average fiber diameter.

[0190] [(D) At least one selected from the group consisting of metal phosphites and metal hypophosphites] D-1: Sodium hypophosphite (manufactured by Wako Pure Chemical Industries, Ltd.)

[0191] [(E) Lubricant] E-1: Calcium montanate (manufactured by Clariant, trade name "Licomont CaV102")

[0192] [(K) Other Polymers] K-1: Polyethylene-polystyrene graft copolymer (trade name "MODIPER-A1100", manufactured by NOF Corporation) K-2: Polyolefin-polyamide polymer (trade name "APOLHYA LP91", manufactured by Arkema K.K.)

[0193] <Raw Materials for Polyamide> (A) Crystalline aliphatic polyamide and (B) crystalline semi-aromatic polyamide used in the Examples and Comparative Examples were produced using the following (a) and (b) as appropriate.

[0194] [(a) Dicarboxylic acids] (a-1) Adipic acid (ADA) (manufactured by Wako Pure Chemical Industries, Ltd.) (a-2) Terephthalic acid (TPA) (manufactured by Wako Pure Chemical Industries, Ltd.)

[0195] [(b) Diamines] (b-1) 1,6-diaminohexane (hexamethylenediamine) (C6DA) (manufactured by Tokyo Chemical Industry Co., Ltd.) (b-2) 1,4-diaminebutane (tetramethylenediamine) (C4DA) (manufactured by Tokyo Chemical Industry Co., Ltd.)

[0196] <Production of Polyamides> Next, a method for producing (A) crystalline aliphatic polyamides A-1, A-2, and A-3 and (B) crystalline semi-aromatic polyamides B-1 and B-2 will be described.

[0197] [Production Example 1] (Production of Crystalline Aliphatic Polyamide A-1 (Polyamide 66)) A polyamide polymerization reaction was carried out by the "hot melt polymerization method" as follows. 1500 g of an equimolar salt of adipic acid and hexamethylenediamine was dissolved in 1500 g of distilled water to prepare a homogeneous aqueous solution containing 50% by mass of the raw material monomers. This aqueous solution was charged into an autoclave with an internal volume of 5.4 L and purged with nitrogen. Next, the solution was concentrated by gradually removing steam to a solution concentration of 70% by mass while stirring at a temperature of 110°C to 150°C. Thereafter, the internal temperature was raised to 220°C. At this time, the autoclave was pressurized to 1.8 MPa. The autoclave was allowed to react for 1 hour while gradually removing steam to maintain the pressure at 1.8 MPa until the internal temperature reached 245°C. Next, the pressure was reduced over 1 hour. The autoclave was then vacuumed at 650 torr (86.66 kPa) for 10 minutes using a vacuum device. The final internal temperature of the polymerization was 265°C. The mixture was then pressurized with nitrogen and formed into strands from the lower spinneret (nozzle). The strands were then water-cooled, cut, and discharged as pellets. The pellets were dried at 100°C under a nitrogen atmosphere for 12 hours to obtain crystalline aliphatic polyamide A-1 (polyamide 66). The Mw(A) was 35,000, Mw(A) / Mn(A) was 2.0, TmA2 was 265°C, crystallization enthalpy ΔH was 68 J / g, and tanδ peak temperature was 80°C.

[0198] [Production Example 2] (Production of crystalline aliphatic polyamide A-2 (polyamide 66)) A polyamide polymerization reaction ("hot melt polymerization method") was carried out in the same manner as in Production Example 1, except that the interior of the autoclave was maintained under a reduced pressure of 650 torr (86.66 kPa) using a vacuum device for 20 minutes, to obtain crystalline aliphatic polyamide A-2 (polyamide 66) pellets. Mw(A) = 40,000, Mw(A) / Mn(A) = 2.0, TmA2 = 265°C, crystallization enthalpy ΔH = 65 J / g, and tan δ peak temperature = 80°C.

[0199] [Production Example 3] (Production of Crystalline Aliphatic Polyamide A-3 (Polyamide 66)) A polyamide polymerization reaction was carried out in the same manner as in Production Example 1 ("hot melt polymerization"), except that the interior of the autoclave was maintained under a reduced pressure of 300 torr (86.66 kPa) using a vacuum device for 10 minutes, to obtain pellets of crystalline aliphatic polyamide A-3 (polyamide 66). Mw(A) = 30,000, Mw(A) / Mn(A) = 2.0, TmA2 = 265°C, crystallization enthalpy ΔH = 70 J / g, and tan δ peak temperature = 80°C.

[0200] [Production Example 4] (Production of crystalline semi-aromatic polyamide B-1 (polyamide 4T / 6T)) With reference to PA-2 in Japanese Patent No. 7043705, crystalline semi-aromatic polyamide B-1 (polyamide 4T / 6T) was produced by adjusting the heating time and other factors so that the following physical properties were obtained: Mw(B) = 18,000, Mw(B) / Mn(B) = 2.1, TmB2 = 335°C, crystallization enthalpy ΔH = 52 J / g, tan δ peak temperature = 160°C, C / N ratio = 6.60, and the proportion of terephthalic acid units in all dicarboxylic acid units was 100 mol%.

[0201] [Production Example 5] (Production of crystalline semi-aromatic polyamide B-2 (polyamide 4T / 6T / 66)) With reference to Example VII of Japanese Patent No. 5,368,111, crystalline semi-aromatic polyamide B-2 (polyamide 4T / 6T / 66) was produced by adjusting the heating time and other factors so that the following physical properties were achieved: Mw(B) = 20,000, Mw(B) / Mn(B) = 2.2, TmB2 = 325°C, crystallization enthalpy ΔH = 54 J / g, tan δ peak temperature = 125°C, C / N ratio = 6.01, and the proportion of terephthalic acid units in all dicarboxylic acid units was 85 mol%.

[0202] <Production of Polyamide Resin Compositions> [Examples 1 to 9 and Comparative Examples 1 to 7] Polyamide resin compositions were produced as follows using (A) crystalline aliphatic polyamide and (B) crystalline semi-aromatic polyamide of the types and proportions shown in Table 1. Each polyamide obtained in the above production examples was dried in a nitrogen stream to adjust the moisture content to about 0.2 mass % before being used as a raw material for the polyamide resin composition.

[0203] A twin-screw extruder [ZSK-26MC: manufactured by Coperion (Germany)] was used as the apparatus for producing the polyamide resin composition. In the twin-screw extruder, the temperature from the upstream supply port to the die was set to the melting point TmA2 of each crystalline aliphatic polyamide (A) produced in the above Production Examples + 50°C, the screw rotation speed was set to 300 rpm, and the output rate was set to 30 kg / h.

[0204] (A) Crystalline aliphatic polyamide and (B) crystalline semi-aromatic polyamide were dry-blended to the types and ratios shown in Table 1, and then fed into the upstream feed port of a twin-screw extruder. The molten mixture extruded from the die head was cooled in the form of strands and pelletized to obtain pellets of a polyamide resin composition (not containing glass fibers).

[0205] Next, we will explain the production of a polyamide resin composition containing 50% by weight of glass fiber (GF) (polyamide:GF = 100 parts by weight: 100 parts by weight) as shown in Table 1. (A) Crystalline aliphatic polyamide and (B) crystalline semi-aromatic polyamide were dry-blended and then fed into the upstream feed port of a twin-screw extruder. (C) Glass fiber C-1 was fed as an inorganic filler into the downstream feed port of the twin-screw extruder. The molten mixture extruded from the die head was cooled in the form of strands and pelletized to obtain pellets of the polyamide resin composition. The resulting pellets of the polyamide resin composition were dried in a nitrogen stream to reduce the moisture content in the polyamide resin composition to 500 ppm or less.

[0206] <Methods for measuring and evaluating physical properties of polyamide and polyamide resin composition> The following various physical properties were measured and evaluated using (A) crystalline aliphatic polyamide, (B) crystalline semi-aromatic polyamide, and the polyamide resin composition after adjusting the water content. The measurement results and evaluation results of the physical properties are shown in Table 1 below.

[0207] [Physical Property 1] (Melting Point TmA2 and Crystallization Enthalpy ΔH) The melting point TmA2 and crystallization enthalpy ΔH of (A) crystalline aliphatic polyamide were measured using a Diamond-DSC manufactured by Perkin-Elmer in accordance with JIS-K7121. Specifically, the measurements were performed as follows. First, in a nitrogen atmosphere, approximately 10 mg of sample was heated from room temperature to 300°C or higher and 350°C or lower depending on the sample at a heating rate of 20°C / min. The highest peak temperature of the endothermic peak (melting peak) that appeared at this time was designated as Tm1 (°C). Next, the temperature was maintained at the highest peak temperature Tm1 of the heating for 2 minutes. At this highest peak temperature Tm1, the polyamide was in a molten state. Thereafter, the temperature was lowered to 30°C at a heating rate of 20°C / min. The exothermic peak that appeared at this time was taken as the crystallization peak, the crystallization peak temperature was taken as Tc, and the crystallization peak area was taken as the crystallization enthalpy ΔH (J / g). After that, the sample was held at 30°C for 2 minutes, and then heated from 30°C to 280°C or higher and 300°C or lower at a heating rate of 20°C / min. The highest peak temperature of the endothermic peak (melting peak) that appeared at this time was taken as the melting point TmA2 (°C).

[0208] [Physical Property 2] (Melting Point TmB2 and Crystallization Enthalpy ΔH) The melting point TmB2 and crystallization enthalpy ΔH of (B) crystalline semi-aromatic polyamide were measured using a Diamond DSC manufactured by Perkin-Elmer in accordance with JIS-K7121. Specifically, the measurements were performed as follows. First, in a nitrogen atmosphere, approximately 10 mg of sample was heated from room temperature to 300°C or higher and 370°C or lower depending on the sample at a heating rate of 20°C / min. The highest peak temperature of the endothermic peak (melting peak) that appeared at this time was designated as Tm1 (°C). Next, the temperature was maintained at the highest peak temperature Tm1 for 2 minutes. At this highest peak temperature Tm1, the polyamide was in a molten state. Thereafter, the temperature was lowered to 30°C at a heating rate of 20°C / min. The exothermic peak that appeared at this time was taken as the crystallization peak, the crystallization peak temperature was taken as Tc, and the crystallization peak area was taken as the crystallization enthalpy ΔH (J / g). After that, the sample was held at 30°C for 2 minutes, and then heated from 30°C to 300°C or higher and 370°C or lower at a heating rate of 20°C / min. The highest peak temperature of the endothermic peak (melting peak) that appeared at this time was taken as the melting point TmB2 (°C).

[0209] [Physical Property 3] (tan δ Peak Temperature and Storage Modulus) For (A) crystalline aliphatic polyamide, (B) crystalline semi-aromatic polyamide, and polyamide resin composition, the temperature dispersion spectra of dynamic viscoelasticity of test specimens prepared by cutting the parallel portion of an ASTM D1822 TYPE L test specimen into strips were measured using a viscoelasticity measurement analyzer ("DVE-V4" manufactured by Rheology Co., Ltd.) under the following conditions. The test specimen dimensions were 3.1 mm (width) × 2.9 mm (thickness) × 15 mm (length: distance between grippers). (Measurement conditions) Measurement mode: Tensile Waveform: Sine wave Frequency: 3.5 Hz Temperature range: 0°C to 180°C Heating step: 2°C / min Static load: 400 g Displacement amplitude: 0.75 μm The ratio of the loss modulus E2 to the storage modulus E1 (E2 / E1) was defined as tan δ, and the highest temperature was defined as the tan δ peak temperature (°C). In addition, the ratio (E'-2 / E'-1) was calculated from the value of the storage modulus E'-2 at 120°C and the value of the storage modulus E'-1 at 23°C.

[0210] [Physical Property 4] (Weight-average molecular weight, number-average molecular weight, molecular weight distribution) For (A) crystalline aliphatic polyamide, (B) crystalline semi-aromatic polyamide, and polyamide resin composition, the weight-average molecular weight and number-average molecular weight were measured using GPC (HLC-8020 manufactured by Tosoh Corporation, hexafluoroisopropanol solvent, converted into a PMMA (polymethyl methacrylate) standard sample (manufactured by Polymer Laboratory Co., Ltd.)). The molecular weight distribution was calculated from the values.

[0211] [Physical Property 5] (Area of ​​Melting Peak of Polyamide Resin Composition) The melting peak ΔHM of the polyamide resin composition was measured in accordance with JIS-K7121 using a Diamond-DSC manufactured by Perkin-Elmer. Specifically, the measurement was performed as follows. First, in a nitrogen atmosphere, approximately 10 mg of a sample was heated from room temperature to 300°C or higher and 370°C or lower depending on the sample at a heating rate of 20°C / min. The highest peak temperature of the endothermic peak (melting peak) that appeared at this time was designated Tm1 (°C). Next, the temperature was maintained at the highest peak temperature Tm1 for 2 minutes. Thereafter, the temperature was decreased to 30°C at a heating rate of 20°C / min. Thereafter, the sample was held at 30°C for 2 minutes, and then heated from 30°C to 300°C or higher and 370°C or lower depending on the sample at a heating rate of 20°C / min. The area of ​​the melting peak appearing at above 150°C was designated as ΔHM1 (J / g), and the percentage (%) of this area relative to the total area ΔHM (J / g) of all endothermic peaks (melting peaks) was calculated.

[0212] [Evaluation 1] (Tensile Strength) For each polyamide resin composition, an ISO dumbbell with a thickness of 4 mm was prepared using an injection molding machine [PS-40E, manufactured by Nissei Plastics Co., Ltd.] and used as a test specimen. Specific molding conditions were an injection + dwell time of 25 seconds, a cooling time of 15 seconds, a mold temperature of 120°C, and a molten resin temperature set to the melting point (TmB2) of the (B) crystalline semi-aromatic polyamide + 20°C. Using the obtained test specimens, a tensile test was performed in accordance with ISO 527 at a temperature of 23°C, with a tensile speed of 50 mm / min for test specimens that did not contain glass and a tensile speed of 5 mm / min for test specimens that contained glass fiber. The tensile yield stress was measured and recorded as the tensile strength (MPa). The temperature condition was set to 120°C, and the other conditions were the same as above, and the tensile strength (MPa) at 120°C was measured. In addition, the test pieces were left in a constant temperature and humidity atmosphere (23°C, 50% RH) and, after reaching water absorption equilibrium, the temperature conditions were changed to 120°C, with the other conditions being the same as above, and the tensile strength (MPa) after water absorption at 120°C was measured. For test pieces not containing glass fibers, those having a tensile strength of 80 MPa or more at a temperature of 23°C, those having a tensile strength of 40 MPa or more at a temperature of 120°C, and those having a tensile strength after water absorption of 33 MPa or more at a temperature of 120°C were evaluated as having good tensile strength under each condition. For test pieces containing glass fibers, those having a tensile strength of 250 MPa or more at a temperature of 23°C, those having a tensile strength of 130 MPa or more at a temperature of 120°C, and those having a tensile strength after water absorption of 100 MPa or more at a temperature of 120°C were evaluated as having good tensile strength under each condition.

[0213] [Evaluation 2] (Notched Charpy Impact Strength) Using the same method as in Evaluation 1 above, an ISO dumbbell having a thickness of 4 mm was prepared for each polyamide resin composition to serve as a test specimen. The obtained test specimens were subjected to the notched Charpy impact strength (kJ / m) test at a temperature of 23°C in accordance with ISO 179. ２ After cooling the test piece in a thermostatic chamber at -40°C for 30 minutes, the notched Charpy impact strength (-40°C notched Charpy impact strength) (kJ / m ２For the test piece not containing glass fiber, the notched Charpy impact strength was measured at a temperature of 23°C. ２ or more, and -40 ° C notched Charpy impact strength is 3.3 kJ / m ２ The notched Charpy impact strength under each temperature condition was evaluated as good if the test piece containing glass fiber had a notched Charpy impact strength of 18 kJ / m or more at a temperature of 23°C. ２ or more, and -40 ° C notched Charpy impact strength is 20 kJ / m ２ Those that met the above criteria were evaluated as having good notched Charpy impact strength under each temperature condition.

[0214] [Evaluation 3] (Tracking Resistance) Using a flat molded body, a test was performed in accordance with IEC 60112 using a tracking resistance tester (manufactured by Yamayo Test Instruments Co., Ltd.), and the tracking resistance index (CTI) was calculated. The higher the tracking resistance index (CTI), the better the tracking resistance was determined to be. The flat molded body was manufactured as follows. [Manufacturing of Flat Molded Body] Using an injection molding machine (NEX50III-5EG, manufactured by Nissei Plastic Industrial Co., Ltd.), the cooling time was set to 25 seconds, the screw rotation speed to 200 rpm, the mold temperature to 80 ° C, and the cylinder temperature to the melting point TmB2 of the (B) crystalline semi-aromatic polyamide + 20 ° C. The injection pressure and injection rate were appropriately adjusted so that the filling time was in the range of 1.6 ± 0.1 seconds, and a flat molded body (6 cm × 9 cm, thickness 2 mm) was manufactured.

[0215] [Evaluation 4] (Dielectric breakdown strength) Using a flat molded body, the dielectric breakdown voltage was measured at a temperature of 120°C in accordance with IEC 60243-1, and then the dielectric breakdown strength (kV / mm) was calculated from the thickness of the flat molded body. For flat molded bodies not containing glass fibers, those having a dielectric breakdown strength of 11.0 kV / mm or more at a temperature of 120°C were evaluated as having good dielectric breakdown strength. For flat molded bodies containing glass fibers, those having a dielectric breakdown strength of 19.0 kV / mm or more at a temperature of 120°C were evaluated as having good dielectric breakdown strength. [Measurement conditions] Pressure increase method: short-time method Pressure increase rate: 1 to 2 kV / s Surrounding medium: silicone oil (23°C) Test electrode: Φ25 mm cylinder / Φ25 mm cylinder Number of measurements: n=5 Conditioning: Stored in a 23°C dry box for 24 hours or more Test room environment: 23°C±2°C, 50% RH±5% RH Measuring device: Dielectric breakdown test device YST-243-100RHO (manufactured by Yamayo Test Instruments Co., Ltd.) Control device: HAT-300-100RHO (manufactured by Yamayo Test Instruments Co., Ltd.) The flat plate molded body was produced as follows. [Production of Plate Molded Article] Using an injection molding machine (NEX50III-5EG, manufactured by Nissei Plastic Industrial Co., Ltd.), a cooling time of 25 seconds, a screw rotation speed of 200 rpm, a mold temperature of 120°C, and a cylinder temperature set to the melting point TmB2 of the crystalline semi-aromatic polyamide (B) + 20°C, the injection pressure and injection rate were appropriately adjusted so that the filling time was in the range of 1.6 ± 0.1 seconds, and a plate molded article (10 cm × 10 cm, thickness 1 mm) was produced.

[0216]

[0217] From Table 1, it can be seen that the polyamide resin composition contains (A) a crystalline aliphatic polyamide and (B) a crystalline semi-aromatic polyamide, and the dicarboxylic acid units contained in the (B) crystalline semi-aromatic polyamide are composed of 90 to 100 mol % of terephthalic acid units, 0 to 10 mol % of one or more aromatic dicarboxylic acid units other than terephthalic acid units, and 0 to 2 mol % of aliphatic dicarboxylic acid units, relative to the total number of moles of dicarboxylic acid units, and the ratio of the number of carbon atoms C to the number of nitrogen atoms N in the (B) crystalline semi-aromatic polyamide ( Molded articles using polyamide resin compositions (Examples 1 to 9) in which the C / N ratio was more than 6.00 and less than 7.00, and the content of (B) the crystalline semi-aromatic polyamide was 10.0% by mass or more and 40.0% by mass or less, relative to 100% by mass of the total mass of all polyamides in the polyamide resin composition, were shown to be excellent in tensile strength and notched Charpy impact strength, and also to be excellent in tensile strength at 120°C, tensile strength after water absorption at 120°C, notched Charpy impact strength at -40°C, tracking resistance, and dielectric breakdown strength at 120°C. In addition, in a comparison of molded articles using polyamide resin compositions (Examples 1 to 3) differing in the content of (B) crystalline semi-aromatic polyamide, the greater the content of (B) crystalline semi-aromatic polyamide relative to the total mass of all polyamides in the polyamide resin composition, the better the tensile strength and notched Charpy impact strength, and the better the tensile strength at 120 ° C. and tensile strength after water absorption, the notched Charpy impact strength at -40 ° C., and the dielectric breakdown strength at 120 ° C. tended to be. In addition, in a comparison of molded articles using polyamide resin compositions (Examples 5 and 6) differing in the presence or absence of (E) lubricant, the inclusion of (E) lubricant tended to result in better notched Charpy impact strength at -40 ° C. and dielectric breakdown strength at 120 ° C. In addition, in a comparison of molded articles using polyamide resin compositions (Examples 1, 7, and 8) differing in the presence or absence of (D) metal phosphate, the inclusion of (D) metal phosphate tended to result in better notched Charpy impact strength at -40 ° C.Furthermore, an addition amount of (D) metal phosphate of 0.01 parts by mass relative to 100 parts by mass of the total mass of (A) crystalline aliphatic polyamide and (B) crystalline semi-aromatic polyamide was better than an addition amount of 0.1 part by mass in terms of tensile strength at 120°C, tensile strength after water absorption at 120°C, notched Charpy impact strength, notched Charpy impact strength at -40°C, tracking resistance, and dielectric breakdown strength at 120°C. Furthermore, in a comparison of molded articles using polyamide resin compositions (Examples 1 and 9) that differed in the presence or absence of (K) other polymer, the inclusion of (K) other polymer tended to result in better notched Charpy impact strength, notched Charpy impact strength at -40°C, and dielectric breakdown strength at 120°C.

[0218] On the other hand, in the case of a molded article using a polyamide resin composition (Comparative Example 1) that did not contain (B) crystalline semi-aromatic polyamide, the tensile strength at 120°C and the tensile strength after water absorption, and the notched Charpy impact strength at -40°C were good, but the tensile strength at 23°C and the notched Charpy impact strength, and the dielectric breakdown strength at 120°C were poor. Also, in the case of a molded article using a polyamide resin composition (Comparative Example 2) in which the content of (B) crystalline semi-aromatic polyamide relative to the total mass of all polyamides in the polyamide resin composition (100% by mass) was more than 40.0% by mass, the tensile strength, the tensile strength at 120°C, and the dielectric breakdown strength at 120°C were good, but the tensile strength after water absorption at 120°C and the notched Charpy impact strength were poor. Furthermore, a molded article using a polyamide resin composition (Comparative Example 3) in which the content of (B) crystalline semi-aromatic polyamide relative to the total mass of all polyamides in the polyamide resin composition was less than 10.0% by mass (100% by mass) showed good tensile strength at 120°C and tensile strength after water absorption at 120°C, but poor tensile strength, notched Charpy impact strength, and dielectric breakdown strength at 120°C. Also, a molded article using a polyamide resin composition (Comparative Example 4) containing (B) crystalline semi-aromatic polyamide in which terephthalic acid units were less than 90 mol% relative to the total number of moles of dicarboxylic acid units showed good tensile strength, 120°C tensile strength, and notched Charpy impact strength, but poor tensile strength after water absorption at 120°C, notched Charpy impact strength at -40°C, and dielectric breakdown strength at 120°C. Molded articles using polyamide resin compositions (Comparative Examples 5 and 6) containing a crystalline semi-aromatic polyamide (B) having a ratio of the number of carbon atoms C to the number of nitrogen atoms N (C / N ratio) of 7.00 or more were good in tensile strength, tensile strength at 120°C, and tensile strength after water absorption at 120°C, but were poor in notched Charpy impact strength, tracking resistance, and dielectric breakdown strength at 120°C. Furthermore, molded articles using a polyamide resin composition (Comparative Example 7) in which the total polyamide content in all resin components was less than 97% by mass were good in notched Charpy impact strength and notched Charpy impact strength at -40°C, but were poor in tensile strength at 120°C, tensile strength at 23°C, tensile strength after water absorption at 120°C, and dielectric breakdown strength at 120°C.

[0219] The polyamide resin composition of this embodiment can provide a polyamide resin composition that, when molded into a molded article, has excellent mechanical properties, particularly mechanical properties such as hot and moist heat properties, impact resistance and tracking resistance under low-temperature conditions, and dielectric breakdown resistance under high-temperature conditions. The molded article of this embodiment can be suitably used as a molding material for various parts for automobiles, especially electric automobiles, electrical and electronic products, industrial materials, industrial materials, and daily necessities and household goods.

Claims

1. A polyamide resin composition containing (A) a crystalline aliphatic polyamide and (B) a crystalline semi-aromatic polyamide containing diamine units and dicarboxylic acid units derived from dicarboxylic acids or their salts or mixtures thereof, wherein the dicarboxylic acid units contained in the (B) crystalline semi-aromatic polyamide consist of 90 to 100 mol% of terephthalic acid units, 0 to 10 mol% of one or more aromatic dicarboxylic acid units other than terephthalic acid units, and 0 to 2 mol% of aliphatic dicarboxylic acid units, based on the total number of moles of the dicarboxylic acid units; the ratio of the number of carbon atoms C to the number of nitrogen atoms N (C / N ratio) in the (B) crystalline semi-aromatic polyamide is more than 6.00 and less than 7.00; and the content of the (B) crystalline semi-aromatic polyamide is 10.0 mass% or more and 40.0 mass% or less based on 100 mass% of the total mass of all polyamides in the polyamide resin composition.

2. The polyamide resin composition according to claim 1, wherein the melting point Tm A2 of the (A) crystalline aliphatic polyamide is 240°C or higher and 270°C or lower.

3. The polyamide resin composition according to claim 1 or 2, wherein the (A) crystalline aliphatic polyamide is polyamide 66 (PA66).

4. The polyamide resin composition according to claim 1 or 2, wherein the diamine units of the (B) crystalline semi-aromatic polyamide consist of diamine units having a linear or branched saturated aliphatic group having 4 to 6 carbon atoms.

5. The polyamide resin composition according to claim 1 or 2, wherein the (B) crystalline semi-aromatic polyamide contains 100 mol% of terephthalic acid units based on the total number of moles of the dicarboxylic acid units.

6. The polyamide resin composition according to claim 1 or 2, wherein the melting point Tm B2 of the (B) crystalline semi-aromatic polyamide is 330°C or higher and 360°C or lower.

7. The polyamide resin composition according to claim 1 or 2, containing 5 to 250 parts by mass of (C) an inorganic filler based on 100 parts by mass of the total mass of the (A) crystalline aliphatic polyamide and the (B) crystalline semi-aromatic polyamide.

8. The polyamide resin composition according to claim 1 or 2, wherein the tanδ peak temperature of the (B) crystalline semi-aromatic polyamide is 150°C or higher.

9. The polyamide resin composition according to claim 1 or 2, comprising at least one selected from the group consisting of metal phosphites and metal hypophosphites.

10. The polyamide resin composition according to claim 1 or 2, wherein the tanδ peak temperature of the polyamide resin composition is 90 °C or higher.

11. The polyamide resin composition according to claim 1 or 2, wherein the weight average molecular weight Mw in the polyamide resin composition is 20,000 or more and 40,000 or less.

12. The polyamide resin composition according to claim 1 or 2, wherein the molecular weight distribution Mw / Mn (Mw is the weight average molecular weight, Mn is the number average molecular weight) of the polyamide resin composition is 2.4 or less.

13. The polyamide resin composition according to claim 1 or 2, wherein the area ΔHM1 of the melting peak above 150 °C of the polyamide resin composition is 95% or more with respect to the total area ΔHM of all the melting peaks in the polyamide resin composition.

14. The polyamide resin composition according to claim 1 or 2, wherein the content of all polyamides is 97% by mass or more with respect to 100% by mass of the mass of all resin components in the polyamide resin composition.

15. The polyamide resin composition according to claim 1 or 2, wherein the ratio (E’-2 / E’-1) of the storage modulus E’-2 at 120 °C to the storage modulus E’-1 at 23 °C of the polyamide resin composition is 0.40 or more.

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