Polyamide composition and molded article

Abstract

Provided is a polyamide composition having excellent metal corrosion resistance properties, weld strength, tensile strength, and flame retardancy. The present invention provides a polyamide composition which contains prescribed amounts of (A) a polyamide, (B) a phosphorus-based flame retardant, and (C) an inorganic filler, and in which said (B) contains a phosphinic acid-phosphonic acid-based composite metal salt represented by general formula (1), and the particle size of said (B) satisfies a prescribed condition.

Description

Polyamide composition and molded article

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

[0002] Polyamides, typified by polyamide 66 (hereinafter also referred to as "PA66"), have excellent moldability, mechanical properties, and chemical resistance, and are therefore widely used as materials for various parts in automobiles, electrical and electronic applications, industrial materials, industrial materials, daily necessities, household goods, and the like.

[0003] Polyamides are often flame-retarded by the addition of halogen compounds. However, recent regulations on hazardous substances, such as RoHS (Restriction of Hazardous Substances) and PoHS (Prohibition on Certain Hazardous Substances in Consumer Products), have led to the establishment of various regulations prohibiting the use of products containing halogen compounds in electrical and electronic components. For this reason, several non-halogen flame retardants for polyamides have been developed.

[0004] Non-halogen flame retardants include, for example, phosphorus compounds. The use of calcium and aluminum salts of phosphinic or diphosphinic acids as flame retardants for polyamides has been disclosed.

[0005] Chinese Patent Application Publication No. 115418026 Chinese Patent Application Publication No. 116285328 Japanese Patent Application Publication No. 2021-50323

[0006] Patent Document 1 discloses a glass fiber reinforced polyamide using aluminum metal salts of phosphinic acid and phosphonic acid. Patent Document 2 discloses a technology of adding a dispersant to a granular composite non-halogen flame retardant. Patent Document 3 discloses a polyamide composition using an aliphatic polyamide, an amorphous aromatic polyamide, and a metal phosphinic acid salt. However, there is room for improvement in mechanical properties, flame retardancy, metal corrosion resistance, weld strength, and extrusion operation stability.

[0007] An object of the present invention is to provide a polyamide composition which is excellent in mechanical properties, flame retardancy, metal corrosion resistance, weld strength, and extrusion operation stability.

[0008] The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a polyamide composition that is excellent in mechanical properties, flame retardancy, metal corrosion resistance, weld strength, and extrusion operation stability.

[0009] As a result of extensive research into solving the above-mentioned problems, the present inventors have found that a polyamide composition containing a phosphinic acid-phosphonic acid complex metal salt having a specific dispersion size can solve the above-mentioned problems, and have thus completed the present invention.

[0010] As described above, in the prior art, there is currently no known polyamide composition that has high metal corrosion resistance, high tensile strength, excellent weld strength, good operational stability and flowability, and is capable of achieving V-0 in the UL94V test.

[0011] The present invention has been made in view of the above circumstances, and provides a polyamide composition having high heat resistance, excellent electrical properties, and excellent flame retardancy, and a molded article using the polyamide composition.

[0012] That is, the present invention includes the following aspects: [1] A polyamide composition comprising, relative to 100% by mass of the total mass of the polyamide composition, 20 to 60% by mass of (A) a polyamide, 10 to 30% by mass of (B) a phosphorus-based flame retardant, and 10 to 60% by mass of (C) an inorganic filler, wherein the phosphorus-based flame retardant (B) comprises at least one phosphinic acid-phosphonic acid complex metal salt selected from the group consisting of condensates of phosphinic acid-phosphonic acid complex metal salts represented by the following general formula (1): (In general formula (1), R １ , R ２ , and R ３ are each independently an alkyl group having 1 to 6 carbon atoms or an aryl group having 6 to 10 carbon atoms, M ｍ＋ is a metal ion; M is an element belonging to Group 2 or 15 of the periodic table, a transition element, zinc, aluminum, or a combination thereof; m is 2 to 3; R １ and R２ If there are multiple R １ and R ２ may be the same or different.) A polyamide composition, wherein the median diameter (D50) of (B) phosphorus-based flame retardant observed in the polyamide composition or a molded article obtained by molding the polyamide composition is 2.5 to 6.0 μm, and the ratio (d75 / d25) of the particle diameter (d25) of the smallest 25% of particles (by number of particles) to the particle diameter (d75) of the smallest 75% of particles (by number of particles) is less than 2.0. [2] The polyamide composition according to [1], wherein M is aluminum. [3] The polyamide composition according to [1] or [2], wherein the (A) polyamide includes (A-1) a crystalline polyamide. [4] The polyamide composition according to [3], wherein the (A) polyamide further comprises (A-2) an amorphous polyamide, the (A-2) amorphous polyamide being a polyamide containing dicarboxylic acid units and diamine units, and wherein the (A-2) amorphous polyamide contains 50 mol% or more of isophthalic acid units among all dicarboxylic acid units constituting the (A-2) amorphous polyamide. [5] The polyamide composition according to [4], wherein the (A-2) amorphous polyamide contains 75 mol% or more of isophthalic acid units among all dicarboxylic acid units constituting the (A-2) amorphous polyamide. [6] The polyamide composition according to [5], wherein the (A-2) amorphous polyamide contains 100 mol% of isophthalic acid units among all dicarboxylic acid units constituting the (A-2) amorphous polyamide. [7] A molded article obtained by molding the polyamide composition according to any one of [1] to [6].

[0013] According to the polyamide composition of the above embodiment, it is possible to provide a polyamide composition that has high low-temperature impact resistance, excellent deflection under load, and excellent flame retardancy when formed into a molded article.

[0014] Hereinafter, a mode for carrying out the present invention (hereinafter simply referred to as "the present embodiment") will be described in detail. The following present embodiment is an example for explaining the present invention, and is not intended to limit the present invention to the following content. The present invention can be carried out by appropriately modifying it within the scope of its gist.

[0015] In this specification, the term "polyamide" refers to a polymer having an amide (-NHCO-) ​​group in the main chain.

[0016] <Polyamide Composition> The polyamide composition of the present embodiment is a polyamide composition comprising, relative to 100% by mass of the total mass of the polyamide composition, 20 to 60% by mass of (A) polyamide, 10 to 30% by mass of (B) phosphorus-based flame retardant, and 10 to 60% by mass of (C) inorganic filler, wherein the (B) phosphorus-based flame retardant comprises at least one phosphinic acid-phosphonic acid complex metal salt selected from the group consisting of condensates of phosphinic acid-phosphonic acid complex metal salts represented by the following general formula (1): (In general formula (1), R １ , R ２ , and R ３ are each independently an alkyl group having 1 to 6 carbon atoms or an aryl group having 6 to 10 carbon atoms, M ｍ＋ is a metal ion; M is an element belonging to Group 2 or 15 of the periodic table, a transition element, zinc, aluminum, or a combination thereof; m is 2 to 3; R １ and R ２ If there are multiple R １ and R ２ may be the same or different.) The polyamide composition is one in which the median diameter (D50) of the phosphorus-based flame retardant (B) observed in the polyamide composition or a molded article obtained by molding the polyamide composition is 5 to 20 μm, and the ratio (d75 / d25) of the particle diameter (d25) of the smallest 25% of particles (by number of particles) to the particle diameter (d75) of the smallest 75% of particles (by number of particles) is less than 2.0. The polyamide composition of this embodiment may contain one or more other components (D) in addition to the above components (A) to (C).

[0017] <(A) Polyamide> Examples of (A) polyamides include polycaprolactam (polyamide 6), polytetramethylene adipamide (polyamide 46), polyhexamethylene adipamide (polyamide 66), polyhexamethylene cyclohexylamide (polyamide 6C), polyhexamethylene sebacamide (polyamide 610), polyhexamethylene dodecamide (polyamide 612), polyundecalactam (polyamide 11), polydodecalactam (polyamide 12), polyhexamethylene isophthalamide (polyamide 6I), polyhexamethylene terephthalamide (polyamide 6T), polynonamethylene terephthalamide (polyamide 9T), polydodecamethylene terephthalamide (polyamide 12T), polymetaxylylene adipamide (polyamide MXD6), and polyamide copolymers obtained by copolymerizing two or more of these polyamides. These polyamides may be used alone or in combination of two or more.

[0018] The polyamide (A) may include a crystalline polyamide (A-1). The polyamide (A) may also include an amorphous polyamide (A-2). Preferably, the polyamide (A) may include a crystalline polyamide (A-1) and an amorphous polyamide (A-2).

[0019] The melting point (Tm) of the (A-1) crystalline polyamide is preferably 290.0° C. or lower, more preferably 280.0° C. or lower, even more preferably 270.0° C. or lower, and preferably 220.0° C. or higher, more preferably 240.0° C. or higher. When the polyamide composition contains the (A-1) crystalline polyamide having a melting point Tm within the above range as the (A) polyamide, a polyamide composition having a melting point Tm corresponding to the melting point Tm of the (A-1) crystalline polyamide can be obtained, and the polyamide composition can be excellent in melt processing such as extrusion and molding, can further suppress the thermal decomposition of the phosphorus-based flame retardant, and has an excellent deflection temperature under load.

[0020] The melting point Tm of the crystalline polyamide (A-1) can be measured in accordance with JIS-K7121 using a differential scanning calorimeter (DSC), more specifically, a Diamond-DSC manufactured by Perkin-Elmer, for example.

[0021] The content of the amorphous polyamide (A-2) relative to the mass of the total polyamide in the polyamide composition is preferably 10.0 mass% or more, more preferably 12.5 mass% or more, even more preferably 15.0 mass% or more, even more preferably 17.5 mass% or more, particularly preferably 20.0 mass% or more, and is preferably 50.0 mass% or less, more preferably 45.0 mass% or less, even more preferably 42.5 mass% or less, even more preferably 40.0 mass% or less, and particularly preferably 35.0 mass% or less. By setting the content of the amorphous polyamide (A-2) within the above range, a polyamide composition having excellent moldability, such as mechanical properties, flame retardancy, and plasticization stability, can be obtained.

[0022] The polyamide composition of this embodiment, having the above-described structure, is a polyamide composition that is excellent in melt processing such as extrusion and molding, and can further suppress the thermal decomposition of the phosphorus-based flame retardant, thereby providing a polyamide composition with excellent moldability and flame retardancy, with an excellent deflection temperature under load. Note that, hereinafter, (A) polyamide, (B) phosphorus-based flame retardant, (C) inorganic filler, and (D) other component may be referred to as component (A), component (B), component (C), and component (D), respectively.

[0023] <<Characteristics of Polyamide Composition>> In the polyamide composition of the present embodiment, the melting point Tm can be set as follows.

[0024] [Melting point Tm of polyamide composition] The melting point Tm of the polyamide composition is preferably 330.0°C or lower, more preferably 300.0°C or lower, even more preferably 290.0°C or lower, even more preferably 280.0°C or lower, and is preferably 220.0°C or higher, more preferably 240.0°C or higher.

[0025] By having the melting point (Tm) of the polyamide composition within the above range, it is possible to obtain a polyamide composition that has excellent mechanical properties, particularly rigidity under atmospheric equilibrium moisture absorption, flame retardancy, and moldability. Furthermore, polyamide compositions containing components such as inorganic fillers have excellent heat resistance, as exemplified by the deflection temperature under load. Furthermore, by having the melting point (Tm) of the polyamide composition within the above range, it is possible to obtain a polyamide composition that is even more excellent in terms of rigidity under heat, etc. The melting point (Tm) of the polyamide composition can be measured in accordance with JIS-K7121, and examples of the measuring device include a Diamond-DSC manufactured by Perkin-Elmer.

[0026] <(A-1) Crystalline Polyamide> A crystalline polyamide is a polyamide having a heat of fusion of crystals of 15 J / g or more when measured at 20° C. / min with a differential scanning calorimeter.

[0027] Examples of the crystalline polyamide (A-1) include, but are not limited to, (A-1a) polyamides obtained by ring-opening polymerization of lactams, (A-1b) polyamides obtained by self-condensation of ω-aminocarboxylic acids, (A-1c) polyamides obtained by condensing diamines and dicarboxylic acids, and copolymers thereof. The crystalline polyamide may be used alone or as a mixture of two or more. Among these, the crystalline polyamide is preferably an aliphatic amide in which the carbon skeleton forming the monomer unit is composed of an aliphatic hydrocarbon group.

[0028] (A-1a) Lactams used to obtain polyamides obtained by ring-opening polymerization of lactams include, but are not limited to, pyrrolidone, caprolactam, undecalactam, and dodecalactam.

[0029] The ω-aminocarboxylic acid (A-1b) used to obtain a polyamide obtained by self-condensation of an ω-aminocarboxylic acid includes, but is not limited to, an ω-amino fatty acid, which is a ring-opening compound of the above-mentioned lactam with water. Two or more monomers of each of the lactam and the ω-aminocarboxylic acid may be used in combination and condensed.

[0030] (A-1c) The diamine (monomer) used to obtain a polyamide obtained by condensing a diamine and a dicarboxylic acid includes, but is not limited to, linear saturated aliphatic diamines having from 2 to 20 carbon atoms, such as ethylenediamine, propylenediamine, tetramethylenediamine, pentamethylenediamine, hexamethylenediamine, heptamethylenediamine, octamethylenediamine, nonamethylenediamine, decamethylenediamine, undecamethylenediamine, dodecamethylenediamine, and tridecamethylenediamine.

[0031] Examples of diamines constituting the 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.

[0032] Among these, 2-methylpentamethylenediamine or 2-methyl-1,8-octanediamine is preferred as the diamine constituting the diamine unit having a substituent branched from the main chain, and 2-methylpentamethylenediamine is more preferred. By including such an aliphatic diamine, the polyamide composition tends to have better heat resistance, rigidity, etc.

[0033] The diamines as the monomers described above may be used alone or in combination of two or more.

[0034] The number of carbon atoms in the diamine unit is preferably 4 to 12, and more preferably 4 to 10. When the number of carbon atoms is equal to or greater than the lower limit, the heat resistance is superior, while when the number of carbon atoms is equal to or less than the upper limit, the crystallinity and releasability are superior.

[0035] The aliphatic diamine may further contain a trivalent or higher polyvalent aliphatic amine such as bishexamethylenetriamine, if necessary. These diamines may be used alone or in combination of two or more.

[0036] (A-1c) Dicarboxylic acids (monomers) used to obtain polyamides obtained by condensing diamines and dicarboxylic acids 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-sodiumsulfoisophthalic acid; and alicyclic dicarboxylic acids such as cyclohexanedicarboxylic acid. The above-mentioned dicarboxylic acids as monomers may be used alone or in combination of two or more.

[0037] The crystalline polyamide (A-1) may further contain, as necessary, units derived from a trivalent or higher polycarboxylic acid such as trimellitic acid, trimesic acid, or pyromellitic acid. The trivalent or higher polycarboxylic acid may be used alone or in combination of two or more.

[0038] Specific examples of the crystalline polyamide (A-1) include 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), polyamide 9T (polynonamethylene terephthalamide), and copolymer polyamides containing these as constituent components.

[0039] Among these, polyamide 6, polyamide 46, polyamide 66, or polyamide 610 is preferred, polyamide 6, polyamide 66, or polyamide 610 is more preferred, polyamide 6 or polyamide 66 is even more preferred, and polyamide 66 is particularly preferred. Polyamide 66 is considered to be a suitable material for connector parts because of its excellent heat resistance, moldability, and toughness.

[0040] [Characteristics of (A-1) Crystalline Polyamide] (Weight-Average Molecular Weight Mw of (A-1) Crystalline Polyamide) The weight-average molecular weight can be used as an index of the molecular weight of (A-1) crystalline polyamide.

[0041] The weight average molecular weight (Mw) of the crystalline polyamide (A-1) is preferably 10,000 or more, more preferably 15,000 or more, even more preferably 20,000 or more, particularly preferably 25,000 or more, and is preferably 50,000 or less, more preferably 45,000 or less, and even more preferably 40,000 or less.

[0042] By ensuring that the Mw is within the above range, it is possible to obtain a polyamide composition that simultaneously satisfies mechanical properties, particularly drip suppression during a combustion test, flowability, corrosion resistance, etc. Furthermore, molded articles obtained from the polyamide composition containing a component typified by an inorganic filler have an improved surface appearance.

[0043] The weight average molecular weight (Mw) of the crystalline polyamide (A-1) can be measured by gel permeation chromatography (GPC).

[0044] (Molecular Weight Distribution of (A-1) Crystalline Polyamide) The molecular weight distribution of (A-1) crystalline polyamide is indicated by Mw / Mn, the value obtained by dividing the weight average molecular weight (Mw) of (A-1) crystalline polyamide by the number average molecular weight (Mn) of (A-1) crystalline polyamide. Mw / Mn of (A-1) crystalline polyamide is preferably 1.0 or more, more preferably 1.8 or more, even more preferably 2.0 or more, and preferably 2.2 or less. When Mw / Mn of (A-1) crystalline polyamide is within the above range, a polyamide composition with more excellent fluidity and the like can be obtained. Furthermore, molded articles obtained from polyamide compositions containing components typified by inorganic fillers have more excellent surface appearance.

[0045] (A-1) Examples of methods for controlling the Mw / Mn of crystalline polyamides within the above range include 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 thermal melt polymerization of polyamides. 2) In addition to the above method 1), a method of controlling polymerization conditions such as heating conditions and reduced pressure conditions.

[0046] The Mw / Mn of the crystalline polyamide (A-1) can be calculated using the Mw and Mn of the crystalline polyamide (A-1) obtained by GPC.

[0047] [Content of (A-1) Crystalline Polyamide] In the polyamide composition of this embodiment, the content of the (A-1) crystalline polyamide is preferably 50.0 mass% or more, more preferably 55.0 mass% or more, even more preferably 57.5 mass% or more, even more preferably 60.0 mass% or more, particularly preferably 62.5 mass% or more, and is preferably 90.0 mass% or less, more preferably 87.5 mass% or less, even more preferably 82.5 mass% or less, and particularly preferably 80.0 mass% or less, relative to the total amount of polyamide in the polyamide composition.

[0048] By adjusting the blending amount of the crystalline polyamide (A-1) within the above range, a polyamide composition having excellent mechanical properties, particularly excellent rigidity when hot, flowability, corrosion resistance, etc. can be obtained.

[0049] In the polyamide composition of the present embodiment, the content of the crystalline polyamide (A-1) relative to the total mass (100% by mass) of the polyamide composition can be, for example, 10.0% by mass or more, 15.0% by mass or more, 20.0% by mass or more, or 25.0% by mass or more, and can be, for example, 60.0% by mass or less, 55.0% by mass or less, 53.0% by mass or less, or 50.0% by mass or less.

[0050] <<(A-2) Amorphous Polyamide>> Amorphous polyamide refers to a polyamide having a crystallization enthalpy ΔH of less than 15 J / g when measured at 20°C / min using a differential scanning calorimeter. The crystallization enthalpy of the amorphous polyamide (A-2) is preferably 10 J / g or less, more preferably 5 J / g or less, and even more preferably 0 J / g. The crystallization enthalpy ΔH can be measured, for example, in accordance with JIS-K7121 using a measuring device such as a Diamond-DSC manufactured by Perkin-Elmer.

[0051] The amorphous polyamide (A-2) is not particularly limited as long as it is a polyamide having a crystallization enthalpy ΔH of not more than the above upper limit, but may be a semi-aromatic polyamide.

[0052] When the amorphous polyamide (A-2) is a semi-aromatic polyamide, it is preferably a polyamide containing (A-2a) dicarboxylic acid units and (A-2b) diamine units. In this case, the amorphous polyamide (A-2) is more preferably a polyamide containing (A-2a) dicarboxylic acid units containing at least 50 mol% isophthalic acid units and (A-2b) diamine units containing at least 50 mol% diamine units having from 4 to 10 carbon atoms.

[0053] The total amount of the isophthalic acid units and diamine units having from 4 to 10 carbon atoms is preferably from 75 mol % to 100 mol %, more preferably from 90 mol % to 100 mol %, and even more preferably 100 mol %, based on the total amount of all structural units of the amorphous polyamide (A-2). In the present invention, the proportion of the predetermined monomer units constituting the amorphous polyamide (A-2) can be measured by nuclear magnetic resonance spectroscopy (NMR) or the like.

[0054] [(A-2a) Dicarboxylic Acid Unit] In the (A-2a) dicarboxylic acid unit, the content of isophthalic acid units relative to the total molar amount of dicarboxylic acid units is preferably 50 mol% or more, particularly preferably 75 mol% or more and 100 mol% or less, further preferably 90 mol% or more and 100 mol% or less, and particularly preferably 100 mol%.

[0055] When the content of isophthalic acid units relative to the total number of moles of dicarboxylic acids is equal to or greater than the above lower limit, a polyamide composition having excellent mechanical properties, rigidity after atmospheric equilibrium moisture absorption, moldability, surface appearance, and flame retardancy can be obtained.

[0056] The dicarboxylic acid unit (A-2a) may contain an aromatic dicarboxylic acid unit other than an isophthalic acid unit, an aliphatic dicarboxylic acid unit, or an alicyclic dicarboxylic acid unit.

[0057] (Aromatic dicarboxylic acid unit) Examples of aromatic dicarboxylic acids constituting the aromatic dicarboxylic acid unit other than the isophthalic acid unit 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.

[0058] The substituent is not particularly limited, but examples thereof include alkyl groups having from 1 to 4 carbon atoms, aryl groups having from 6 to 10 carbon atoms, arylalkyl groups having from 7 to 10 carbon atoms, halogen groups such as chloro groups and bromo groups, silyl groups having from 1 to 6 carbon atoms, sulfonic acid groups and salts thereof (sodium salts, etc.), and the like.

[0059] Specific examples include, but are not limited to, aromatic dicarboxylic acids having 8 to 20 carbon atoms, which are unsubstituted or substituted with a specific substituent, such as terephthalic acid, naphthalenedicarboxylic acid, 2-chloroterephthalic acid, 2-methylterephthalic acid, 5-methylisophthalic acid, and 5-sodiumsulfoisophthalic acid. Of these, terephthalic acid is preferred. The aromatic dicarboxylic acids constituting the aromatic dicarboxylic acid unit may be used alone or in combination of two or more.

[0060] (Aliphatic Dicarboxylic Acid Unit) Examples of aliphatic dicarboxylic acids constituting the aliphatic dicarboxylic acid unit include, but are not limited to, linear or branched saturated aliphatic dicarboxylic acids having 3 to 20 carbon atoms, such as 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, and diglycolic acid.

[0061] (Alicyclic Dicarboxylic Acid Unit) Examples of alicyclic dicarboxylic acids constituting the alicyclic dicarboxylic acid unit (hereinafter also referred to as "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.

[0062] The alicyclic group of the alicyclic 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, such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, and tert-butyl. The dicarboxylic acid unit other than the isophthalic acid unit preferably contains an aromatic dicarboxylic acid unit, more preferably an aromatic dicarboxylic acid having 6 to 12 carbon atoms. The use of such a dicarboxylic acid tends to improve the mechanical properties of the polyamide composition, particularly the water absorption rigidity, hot rigidity, fluidity, surface appearance, and corrosion resistance.

[0063] In the polyamide composition of this embodiment, the dicarboxylic acid constituting the (A-2a) 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.

[0064] Furthermore, the amorphous polyamide (A-2) may further contain, as necessary, units derived from a trivalent or higher polycarboxylic acid such as trimellitic acid, trimesic acid, pyromellitic acid, etc. The trivalent or higher polycarboxylic acid may be used alone or in combination of two or more.

[0065] [(A-2b) Diamine Unit] The (A-2b) diamine unit constituting the (A-2) amorphous polyamide preferably contains at least 50 mol % of diamine units having from 4 to 10 carbon atoms. Examples include, but are not limited to, aliphatic diamine units, alicyclic diamine units, and aromatic diamine units.

[0066] (Aliphatic Diamine Unit) Examples of aliphatic diamines 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.

[0067] (Alicyclic Diamine Unit) Examples of alicyclic diamines (hereinafter also referred to as "alicyclic diamines") constituting the alicyclic diamine unit include, but are not limited to, 1,4-cyclohexanediamine, 1,3-cyclohexanediamine, 1,3-cyclopentanediamine, and the like.

[0068] (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.

[0069] Among these, aliphatic diamine units are preferred, diamine units having a linear saturated aliphatic group having from 4 to 10 carbon atoms are more preferred, diamine units having a linear saturated aliphatic group having from 6 to 10 carbon atoms are even more preferred, and hexamethylenediamine units are particularly preferred. The use of such diamines tends to result in polyamide compositions that are more excellent in mechanical properties, particularly water absorption rigidity, hot rigidity, fluidity, surface appearance, corrosion resistance, etc. The diamines may be used alone or in combination of two or more.

[0070] The amorphous polyamide (A-2) is preferably polyamide 6I, 6I / 6T, 9I, or 10I, more preferably 6I or 6I / 6T, and most preferably 6I.

[0071] The amorphous polyamide (A-2) 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.

[0072] [At least one unit selected from the group consisting of lactam units and aminocarboxylic acid units] The amorphous polyamide (A-2) can further contain at least one unit selected from the group consisting of lactam units and aminocarboxylic acid units. By including such units, polyamides with superior toughness tend to be obtained. Here, the lactam and aminocarboxylic acid constituting the lactam units and aminocarboxylic acid units refer to lactams and aminocarboxylic acids that can be polymerized (condensed).

[0073] The lactam and aminocarboxylic acid constituting the lactam unit and aminocarboxylic acid unit are not limited to the following, but for example, lactams and aminocarboxylic acids having from 4 to 14 carbon atoms are preferred, and lactams and aminocarboxylic acids having from 6 to 12 carbon atoms are more preferred.

[0074] 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 composition tends to have better toughness.

[0075] 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.

[0076] The lactam and aminocarboxylic acid constituting the lactam unit and aminocarboxylic acid unit may be used alone or in combination of two or more kinds.

[0077] 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.

[0078] [Characteristics of (A-2) Amorphous Polyamide] (Weight-Average Molecular Weight Mw of (A-2) Amorphous Polyamide) The weight-average molecular weight (Mw) of (A-2) Amorphous Polyamide can be used as an index of the molecular weight of (A-2) Amorphous Polyamide.

[0079] The weight average molecular weight (Mw) of the amorphous polyamide (A-2) is preferably 10,000 or more, more preferably 13,000 or more, even more preferably 15,000 or more, particularly preferably 18,000 or more, and most preferably 19,000 or more; it is preferably 35,000 or less, more preferably 33,000 or less, even more preferably 30,000 or less, even more preferably 29,000 or less, particularly preferably 27,000 or less, and most preferably 21,000 or less.

[0080] When the weight-average molecular weight (Mw) of the amorphous polyamide (A-2) is within the above range, a polyamide composition having excellent mechanical properties, particularly excellent water absorption rigidity, hot rigidity, and flame retardancy, can be obtained. Furthermore, molded articles obtained from the polyamide composition containing a component such as an inorganic filler have excellent surface appearance.

[0081] Furthermore, in order to reduce the number average particle size of the domains in the crystalline polyamide (A-1), it is desirable to improve the physical kneading efficiency, and the number average particle size can be reduced by bringing the melt viscosity in the molten state closer to that of the crystalline polyamide.

[0082] Amorphous polyamide (A-2), which contains an aromatic compound unit in its molecular structure, has a higher melt viscosity when it has the same molecular weight as crystalline polyamide (A). Therefore, it is desirable that the molecular weight of the amorphous polyamide (A-2) be smaller than that of crystalline polyamide (A-1).

[0083] The weight average molecular weight (Mw) of the amorphous polyamide (A-2) can be measured using GPC.

[0084] (Molecular Weight Distribution of (A-2) Amorphous Polyamide) The molecular weight distribution of (A-2) amorphous polyamide is indicated by Mw / Mn, which is the value obtained by dividing the weight average molecular weight (Mw) of (A-2) amorphous polyamide by the number average molecular weight (Mn) of (A-2) amorphous polyamide.

[0085] The Mw / Mn of the amorphous polyamide (A-2) is preferably 1.0 or more, more preferably 1.3 or more, even more preferably 1.5 or more, particularly preferably 1.8 or more, most preferably 2.0 or more, and is preferably 2.6 or less, more preferably 2.5 or less, and even more preferably 1.8 or more and 2.4 or less. When the Mw / Mn of the amorphous polyamide (A-2) is within the above range, a polyamide composition with excellent moldability and appearance can be obtained. Furthermore, molded articles obtained from polyamide compositions containing components such as inorganic fillers have excellent surface appearance.

[0086] (A-2) Examples of methods for controlling the Mw / Mn of the amorphous polyamide within the above range include 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 the 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.

[0087] When the molecular structure of a polyamide contains aromatic compound units, the molecular weight distribution (Mw / Mn) of the amorphous polyamide (A-2) tends to increase as the molecular weight increases. A high molecular weight distribution of the amorphous polyamide (A-2) indicates a high proportion of polyamide molecules having a three-dimensional molecular structure. Reducing the proportion of polyamide molecules having a three-dimensional molecular structure increases compatibility with the crystalline polyamide (A-1) and reduces the number-average particle size of the domains. Therefore, by controlling the Mw / Mn of the amorphous polyamide (A-2) within the above range, the progression of three-dimensional molecular structuring during high-temperature processing is suppressed, resulting in a polyamide composition with excellent flowability, better weld strength, and improved product appearance. Furthermore, the surface appearance of molded articles obtained from polyamide compositions containing components such as inorganic fillers is improved.

[0088] The Mw / Mn of the amorphous polyamide (A-2) can be calculated using the Mw and Mn of the amorphous polyamide (A-2) obtained by GPC.

[0089] (Crystallization enthalpy ΔH of (A-2) amorphous polyamide) From the viewpoint of appearance, the crystallization enthalpy ΔH of the (A-2) amorphous polyamide is preferably 15 J / g or less, more preferably 10 J / g or less, even more preferably 5 J / g or less, and particularly preferably 0 J / g. As a method for controlling the crystallization enthalpy ΔH of the (A-2) amorphous polyamide within the above range, known methods for reducing the crystallinity of polyamides can be used, and are not particularly limited. Specific examples of known methods for reducing the crystallinity of polyamides include a method of increasing the ratio of meta-substituted aromatic dicarboxylic acid units to dicarboxylic acid units, and a method of increasing the ratio of meta-substituted aromatic diamine units to diamine units. From this viewpoint, the amorphous polyamide (A-2) preferably contains, as dicarboxylic acid units (A-2a), isophthalic acid units in an amount of 50 mol% or more, more preferably 75 mol% or more, and even more preferably 100 mol% of all dicarboxylic acid units constituting the amorphous polyamide (A-2).

[0090] The crystallization enthalpy ΔH of the amorphous polyamide (A-2) can be measured, for example, in accordance with JIS-K7121 using a measuring device such as Diamond-DSC manufactured by Perkin-Elmer.

[0091] [Content of (A-2) Amorphous Polyamide] In the polyamide composition of the present embodiment, the content of the amorphous polyamide (A-2) relative to the total mass (100 mass%) of the polyamide composition can be, for example, 1.0 mass% to 60.0 mass%; 3.0 mass% to 40.0 mass%; 5.0 mass% to 30.0 mass%; or 7.0 mass% to 25.0 mass%; for example, 1.0 mass% to 60.0 mass%; 3.0 mass% to 40.0 mass%; 5.0 mass% to 30.0 mass%; or 7.0 mass% to 25.0 mass%.

[0092] <End-capping agent> At least one polyamide selected from the group consisting of (A-1) crystalline polyamide and (A-2) amorphous polyamide has its ends capped with an end-capping agent. Such an end-capping agent can also be added as a molecular weight regulator 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.

[0093] Examples of end-capping agents include, but are not limited to, acid anhydrides, monoisocyanates, monoacid halides, monoesters, and monoalcohols. Examples of acid anhydrides include monocarboxylic acids, monoamines, and phthalic anhydride. Among these, monocarboxylic acids and monoamines are preferred. Capping the polyamide ends with an end-capping agent tends to result in a polyamide composition with superior thermal stability. The end-capping agents may be used alone or in combination of two or more.

[0094] 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 of two or more.

[0095] Monoamines that can be used as end-capping agents may be any monoamines that are 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 amines include, but are not limited to, methylamine, ethylamine, propylamine, butylamine, hexylamine, octylamine, decylamine, stearylamine, dimethylamine, diethylamine, dipropylamine, and dibutylamine. Examples of alicyclic amines include, but are not limited to, cyclohexylamine and dicyclohexylamine. Examples of aromatic amines include, but are not limited to, aniline, toluidine, diphenylamine, and naphthylamine. These monoamines may be used alone or in combination of two or more.

[0096] Polyamide compositions containing polyamides end-capped with an end-capping agent tend to have excellent heat resistance, flowability, toughness, low water absorption, rigidity, corrosion resistance, moldability, and appearance.

[0097] <Method for producing polyamide> When obtaining each polyamide ((A-1) crystalline polyamide and (A-2) amorphous polyamide), the amount of dicarboxylic acid added and the amount of diamine added are preferably approximately the same molar amount. Taking into consideration 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 or more, more preferably 0.95 or more, and even more preferably 0.98 or more, and is preferably 1.2 or less, more preferably 1.1 or less, and even more preferably 1.05 or less.

[0098] The method for producing polyamide includes, but is not limited to, the following polymerization steps (1) or (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.

[0099] 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.

[0100] Specific methods for producing polyamides include the following various methods exemplified by 1) to 4). 1) A method in which an aqueous solution or suspension of one or more selected from the group consisting of dicarboxylic acid-diamine salts, mixtures of dicarboxylic acids and diamines, lactams, and aminocarboxylic acids is heated and polymerized while maintaining the molten state (hereinafter sometimes referred to as "thermal melt polymerization"). 2) A method in which the degree of polymerization of polyamides obtained by thermal melt polymerization is increased while maintaining the solid state at a temperature below the melting point (hereinafter sometimes referred to as "thermal melt polymerization / solid-state polymerization"). 3) A method in which one or more selected from the group consisting of dicarboxylic acid-diamine salts, mixtures of dicarboxylic acids and diamines, lactams, and aminocarboxylic acids are polymerized while maintaining the solid state (hereinafter sometimes referred to as "solid-state polymerization"). 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 "solution method").

[0101] Among these, a specific method for producing polyamide is preferably a production method including a hot melt polymerization method. When producing polyamide by the hot melt polymerization method, it is preferable to maintain the molten state until the polymerization is completed. In order to maintain the molten state, it is necessary to produce polyamide under polymerization conditions suitable for the polyamide. Examples of the polymerization conditions include the following conditions. First, the polymerization pressure in the hot melt polymerization method is set to 14 kg / cm. ２ More than 25kg / cm ２ Heating is continued while controlling the pressure in the vessel to atmospheric pressure (gauge pressure is 0 kg / cm ２ ) and reduce the blood pressure over 30 minutes or more until the blood pressure reaches a normal level.

[0102] 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).

[0103] Hereinafter, as a method for producing polyamide, a method for producing polyamide by batch-type hot melt polymerization will be specifically shown, but the method for producing polyamide is not limited to this.

[0104] First, an aqueous solution containing about 40% by mass to about 60% by mass of raw material components for polyamide (a combination of a dicarboxylic acid and a diamine, and optionally at least one selected from the group consisting of a lactam and an aminocarboxylic acid) is prepared. Next, the aqueous solution is concentrated to about 65% by mass to about 90% by mass 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.

[0105] The resulting concentrated solution is then transferred to an autoclave, and heating is continued until the pressure in the autoclave reaches approximately 1.2 MPa to 2.2 MPa (gauge pressure). The pressure in the autoclave is then maintained at approximately 1.2 MPa to 2.2 MPa (gauge pressure) while removing at least one of water and gas components. When the temperature reaches approximately 220°C to 260°C, the pressure is reduced to atmospheric pressure (gauge pressure: 0 MPa). After the pressure in the autoclave is reduced to atmospheric pressure, the pressure can be reduced as needed to effectively remove the by-product water.

[0106] The autoclave is then pressurized with an inert gas such as nitrogen, and the polyamide melt is extruded from the autoclave as a strand. The extruded strand is cooled and cut to obtain polyamide pellets.

[0107] <Polymer Terminals of Polyamide> The polymer terminals of the polyamides ((A-1) crystalline polyamide and (A-2) amorphous polyamide) contained in the polyamide composition of the present embodiment are not particularly limited, but can be classified and defined as follows: 1) amino terminals, 2) carboxy terminals, 3) terminals due to a capping agent, and 4) other terminals. 1) An amino terminal is an amino group (-NH ２ 1) Terminal ends are polymer ends having a carboxy group (-COOH group) and are derived from diamine units. 2) Terminal ends are polymer ends having a carboxy group (-COOH group) and are derived from dicarboxylic acids. 3) Terminal ends formed by a capping agent are ends formed when a capping agent is added during polymerization. Examples of the capping agent include the terminal capping agents described below. 4) Other terminals are polymer terminals that do not fall into the above categories 1) to 3). Specific examples of other terminals include terminals formed by deammonia reaction of amino terminals and terminals formed by decarboxylation of carboxy terminals.

[0108] <<(B) Phosphorus-Based Flame Retardant: Phosphinic Acid-Phosphonic Acid Complex Metal Salts>> Specific examples of the phosphinic acid flame retardant include at least one phosphinic acid-phosphonic acid complex metal salt selected from the group consisting of condensates (derivatives) of phosphinic acid-phosphonic acid complex metal salts represented by the following general formula (1):

[0109]

[0110] In general formula (1), R １ , R ２ , and R ３ are each independently an alkyl group having 1 to 6 carbon atoms or an aryl group having 6 to 10 carbon atoms. ｍ＋ is a metal ion. M is an element belonging to Group 2 or 15 of the periodic table, a transition element, zinc, aluminum, or a combination thereof. m is 2 to 3. R １ and R ２ If there are multiple R １ and R ２ may be the same or different.

[0111] The median diameter (D50) of component (B) observed from the polyamide composition (e.g., in the form of pellets) or a molded article obtained by molding the polyamide composition is 2.5 to 6.0 μm. The ratio (d75 / d25) of the particle diameter (d25) of the smallest 25% (by number of particles) of particles to the particle diameter (d75) of the smallest 75% (by number of particles) of particles is less than 2.0.

[0112] [R １ , R ２ , and R ３ ] R １ , R ２ , and R ３ are each independently an alkyl group having 1 to 6 carbon atoms or an aryl group having 6 to 10 carbon atoms. １ and R ２ If there are multiple R １ and R ２ may be the same or different, but are preferably the same in view of ease of production.

[0113] The alkyl group may be chain-like or cyclic, but is preferably chain-like. The chain-like alkyl group may be linear or branched. Examples of the linear alkyl group 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 a 1-methylethyl group, a 1-methylpropyl group, a 2-methylpropyl group, a 1,1-dimethylethyl group, a 1-methylbutyl group, a 2-methylbutyl group, a 3-methylbutyl group, a 1,1-dimethylpropyl group, a 1,2-dimethylpropyl group, a 2,2-dimethylpropyl group, a 1-methylpentyl group, a 2-methylpentyl group, a 3-methylpentyl group, a 4-methylpentyl group, a 1,1-dimethylbutyl group, a 1,2-dimethylbutyl group, a 1,3-dimethylbutyl group, a 2,2-dimethylbutyl group, a 2,3-dimethylbutyl group, a 3,3-dimethylbutyl group, a 1-ethylbutyl group, a 2-ethylbutyl group, and a 1,1,2-trimethylpropyl group.

[0114] Examples of the aryl group include a phenyl group and a naphthyl group.

[0115] The alkyl group and the aryl group may have a substituent. Examples of the substituent in the alkyl group include an aryl group having 6 to 10 carbon atoms. Examples of the substituent in the aryl group include an alkyl group having 1 to 6 carbon atoms.

[0116] [M] M is independently an element belonging to Group 2 or Group 15 of the periodic table, a transition element, zinc, aluminum, or a combination thereof. Examples of elements belonging to Group 2 of the periodic table include calcium and magnesium. Examples of elements belonging to Group 15 of the periodic table include bismuth. Among these, aluminum is preferred as M.

[0117] [m+] m+ represents the average cation valence of M, which is 2 to 3. The cation valence of each M is 2 or 3. m+ can be appropriately selected depending on the type of M and the number of diphosphinic acids.

[0118] [a and b] a represents the average number of phosphinic acid anions per molecule. It can be selected appropriately depending on the type and number of M. b represents the average number of phosphonic acid anions per molecule. It can be selected appropriately depending on the type and number of M. When the average number of M per molecule is c, a, b, c, and m can usually be selected appropriately so that the formula a + 2 × b = c × m holds.

[0119] Furthermore, among phosphinates, a flame retardant represented by chemical formula (1), which is a composite salt of a phosphinate and a phosphonate, is preferred from the viewpoints of heat resistance, flame retardancy, and metal corrosion resistance.

[0120] Most preferably, R in formula (3) １ = ethyl group, R ２ = ethyl group, R ３ = ethyl group, a = 4, b = 1 hexavalent anion, and two hexavalent cations with M = aluminum and m = 3. Specific examples of products include "HR8900," "MADP8900SP," "MADP8900BS," and "HR8966" manufactured by Weihai Hairun Co., Ltd.

[0121] The flame retardant may be in the form of a powder, columnar, or flake, but from the viewpoint of extrusion operability and dispersibility, the columnar and flake types are preferred. Bulk density: 0.4 to 0.9 g / cm ３ is preferable, and more preferably, 0.5 to 0.8 g / cm ３ More preferably, it is 0.6 to 0.7 g / cm ３ By setting the value within this range, less air is brought in during feeding, the torque is stabilized, and dispersion in the extruder is facilitated. The collapse strength is preferably 0.1 N or more, more preferably 1 N or more, even more preferably 5 N or more, and preferably 50 N or less, more preferably 30 N or less, and even more preferably 20 N or less. By setting the value within this range, a polyamide composition excellent in continuous operability and dispersibility can be obtained. The collapse strength can be measured as follows.

[0122] [Measurement of Collapse Strength] For example, the collapse stress (unit: N) as the collapse strength of the flame retardant can be measured using a Kiya hardness tester (manufactured by Fujiwara Seisakusho Co., Ltd., product name "043019-A"). The measured value may be the average value of 25 granules.

[0123] Bulk density can be measured as follows.

[0124] [Bulk Density] For example, the flame retardant granules are allowed to fall naturally into a 1-liter measure, the measure is filled to the brim, and a volume of exactly 1 liter is weighed and the weight is measured, thereby calculating the bulk density (unit: g / ml) of the flame retardant granules.

[0125] The content of the phosphorus-based flame retardant is preferably 10% by mass or more, more preferably 12% by mass or more, particularly preferably 14% by mass or more, and preferably 30% by mass or less, more preferably 25% by mass or less, particularly preferably 20% by mass or less, based on the total mass of the (A-1) crystalline polyamide and the (A-2) amorphous polyamide. By setting the content of the phosphorus-based flame retardant to the above-mentioned lower limit or more, a polyamide composition with superior flame retardancy can be obtained. On the other hand, by setting the amount of the phosphorus-based flame retardant to the above-mentioned upper limit or less, a polyamide composition with superior flame retardancy can be obtained without impairing the properties of the polyamide.

[0126] From the viewpoints of mechanical properties, flame retardancy, and molding flowability, the dispersed particle size of the phosphorus-based flame retardant has a median diameter (D50) of 2.5 μm or more, preferably 3.0 μm or more, and 6.0 μm or less, preferably 5.0 μm or less. Furthermore, the ratio (d75 / d25) of the particle size (d25) of the smallest 25% (particle number) of particles to the particle size (d75) of the smallest 75% (particle number) of particles is preferably less than 2.0, more preferably less than 1.9. By adjusting the ratio to be equal to or greater than the above lower limit, a polyamide composition having excellent flame retardancy and metal corrosion resistance can be obtained. The dispersed particle size of the phosphorus-based flame retardant can be calculated based on images observed using a digital microscope, SEM, or the like.

[0127] <<(C) Inorganic Filler>> The polyamide composition of the present embodiment further contains (C) an inorganic filler in addition to the components (A) and (B).

[0128] Examples of inorganic fillers include, but are not limited to, glass fibers, carbon fibers, calcium silicate fibers, potassium titanate fibers, aluminum borate fibers, clay, flaked glass, 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.

[0129] 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. Glass fiber is most preferred.

[0130] When the 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.

[0131] By setting the number average fiber diameter to the above upper limit or less, a polyamide composition having excellent toughness and surface appearance of a molded product can be obtained. On the other hand, by setting the number average fiber diameter to the above lower limit or more, a polyamide composition having an excellent balance between cost, powder handling, and physical properties (fluidity, etc.) can be obtained. Furthermore, by setting the number average fiber diameter to 3 μm or more and 9 μm or less, a polyamide composition having excellent vibration fatigue properties and sliding properties can be obtained.

[0132] When the inorganic filler is glass fiber or carbon fiber, its cross section may be either perfectly circular or flat. Examples of such flat cross sections include, but are not limited to, rectangular, oval-like, elliptical, and cocoon-shaped cross sections with a narrowed central portion in the longitudinal direction. Here, the term "flattening" as used herein refers to the value expressed as d2 / d1, where d2 is the major axis of the fiber cross section and d1 is the minor axis of the fiber cross section (a perfectly circular cross section has a flattening of approximately 1).

[0133] When the inorganic filler is glass fiber or carbon fiber, from the viewpoint of imparting excellent mechanical strength to the polyamide composition, it is particularly preferable 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. The "number average fiber diameter (d)" referred to here is the average value of the major diameter (d2) of the fiber cross section, and is determined using the calculation method described below.

[0134] Furthermore, from the viewpoint of reducing warpage of a plate-shaped molded product and improving heat resistance, toughness, low water absorption, and heat aging resistance, the aspect ratio is preferably 1.5 or more, more preferably 2.5 or more, particularly preferably more than 3.0, most preferably 3.1 or more, and preferably 10.0 or less, more preferably 10.0 or less, and most preferably 6.0 or less. When the aspect ratio is within the above range, crushing can be more effectively prevented during processing such as mixing with other components, kneading, and molding, and the desired effects for the molded product can be more fully obtained.

[0135] 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 diameter d1 of the fiber cross section is 0.5 μm or more and 25 μm or less, and the major diameter d2 of the fiber cross section is 1.25 μm or more and 250 μm or less. It is more preferable that the minor diameter d1 of the fiber cross section is 3.0 μm or more and 25 μm or less, and the major diameter d2 of the fiber cross section is 1.25 μm or more and 250 μm or less. By having the minor diameter (d1) and major diameter (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 article without reducing the contact area with the resin (polyamide).

[0136] The glass fibers or carbon fibers having an aspect ratio of 1.5 or more are preferably glass fibers produced using either an orifice plate having a large number of orifices on its bottom surface and having convex edges 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 fibrous reinforcing materials may be used as they are as fiber strands in the form of roving, or may be further cut and used as chopped glass strands.

[0137] 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 composition is placed in an electric furnace, and the organic matter contained therein is incinerated. 100 or more glass fibers (or carbon fibers) are arbitrarily selected from the residue after the incineration treatment, and observed with a scanning electron microscope (SEM). The fiber diameters (major axes) of these glass fibers (or carbon fibers) are measured, thereby determining the number average fiber diameter. In addition, the weight average fiber length can be determined by measuring the fiber lengths using an SEM photograph of the 100 or more glass fibers (or carbon fibers) taken at 1000x magnification.

[0138] 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.

[0139] 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 the silane coupling agent.

[0140] Glass fibers or carbon fibers may further contain a sizing agent. Examples of sizing agents include copolymers containing, as structural units, carboxylic acid anhydride-containing unsaturated vinyl monomers and unsaturated vinyl monomers other than carboxylic acid anhydride-containing unsaturated vinyl monomers, 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.

[0141] Among these, from the viewpoint of the mechanical strength of the resulting polyamide composition, the sizing agent is preferably one or more selected from the group consisting of a copolymer 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, an epoxy compound, and a polyurethane resin, and more preferably one or more selected from the group consisting of a copolymer 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, and a polyurethane resin.

[0142] Glass fibers or carbon fibers can be obtained by applying the sizing agent to the fibers using a known method such as a roller applicator in a known fiber production process, and then drying the produced fiber strands to continuously react them. The fiber strands can be used as rovings as they are, or can be further cut into chopped glass strands.

[0143] The sizing agent is preferably added in an amount of about 0.2% by mass or more, more preferably about 0.3% by mass or more, preferably about 3% by mass or less, and more preferably 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 composition is further improved. Drying of the strands may be performed after the cutting step, or the strands may be cut after drying.

[0144] As inorganic fillers other than glass fiber and carbon fiber, from the viewpoint of improving the strength, rigidity, and surface appearance of the molded article, wollastonite, kaolin, mica, talc, calcium carbonate, magnesium carbonate, potassium titanate fiber, aluminum borate fiber, or clay is preferred. Wollastonite, kaolin, mica, talc, calcium carbonate, or clay is more preferred. Wollastonite, kaolin, mica, or talc is even more preferred. Wollastonite, mica, or talc is particularly preferred. These inorganic fillers may be used alone or in combination of two or more.

[0145] 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, more preferably 0.03 μm or more, even more preferably 0.05 μm or more, even more preferably 0.10 μm or more, particularly preferably 0.15 μm or more, and is preferably 38 μm or less, more preferably 30 μm or less, even more preferably 25 μm or less, even more preferably 20 μm or less, and particularly preferably 15 μm or less.

[0146] By setting the average particle size of the inorganic filler other than the glass fiber and carbon fiber to the above upper limit or less, a polyamide composition having superior toughness and surface appearance of a molded product can be obtained. On the other hand, by setting the average particle size to the above lower limit or more, a polyamide composition having an excellent balance between cost, powder handling, and physical properties (flowability, etc.) can be obtained.

[0147] For needle-shaped inorganic fillers such as wollastonite other than glass fiber and carbon fiber, the number average particle diameter (hereinafter sometimes simply referred to as "average particle diameter") is taken as the average particle diameter. If the cross section is not circular, the maximum length is taken as the (number average) fiber diameter.

[0148] The number average particle length (hereinafter sometimes simply referred to as "average particle length") of the acicular inorganic filler is preferably within a numerical range calculated from the above-mentioned preferred range of the number average particle diameter and the preferred range of the aspect ratio (l / d) of the number average particle length (l) to the number average particle diameter (d) described below.

[0149] Although the particles have a needle-like shape, the aspect ratio (l / d) of the number average particle length (l) to the number average particle diameter (d) is preferably 1.5 or more, more preferably 2.0 or more, and even more preferably 2.5 or more, from the viewpoints of improving the surface appearance of molded articles and preventing wear of metal parts of injection molding machines and the like, and is preferably 10 or less, more preferably 5 or less, and even more preferably 4 or less.

[0150] 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.

[0151] [(C) Content of inorganic filler] The content of inorganic filler is preferably 5% by mass or more, more preferably 20% by mass or more, even more preferably 25% by mass or more, particularly preferably 30% by mass or less, most preferably 35% by mass or more, more preferably 70% by mass or less, more preferably 65% ​​by mass or less, even more preferably 60% by mass or less, and most preferably 50% by mass or less, based on the total mass (100% by mass) of the polyamide composition. When the content of inorganic filler is equal to or greater than the lower limit, the strength and rigidity of the resulting polyamide composition can be improved. On the other hand, when the content of inorganic filler is equal to or less than the upper limit, a polyamide composition having better extrudability and moldability can be obtained.

[0152] <<(D) Other Components>> In addition to the components (A) to (C), the polyamide composition of the present embodiment may include one or more (D) other components selected from the group consisting of flame retardant auxiliaries, lubricants, heat stabilizers, phosphorus-based flame retardants, nucleating agents, other polymers, and other additives.

[0153] [Flame Retardant Coagent] Anhydrous zinc borate can be used as a flame retardant coagent. When anhydrous zinc borate is selected, the ratio of anhydrous zinc borate to (B) the phosphorus-based flame retardant is preferably 2:98 to 10:90 from the viewpoint of flame retardancy efficiency.

[0154] [Lubricant] The lubricant is not particularly limited, but examples thereof include higher fatty acids, higher fatty acid metal salts, higher fatty acid esters, higher fatty acid amides, etc. The lubricant can also be used as a molding improver.

[0155] (Higher Fatty Acids) Examples of higher fatty acids 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 higher fatty acids.

[0156] (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 2 elements of the periodic table or aluminum are preferred, and sodium, potassium, calcium, magnesium, or aluminum is more preferred.

[0157] 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.

[0158] (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.

[0159] (Higher fatty acid amide) Higher fatty acid amide is an amide compound of a higher fatty acid. Examples of higher fatty acid amide include stearic acid amide, oleic acid amide, erucic acid amide, ethylene bisstearylamide, ethylene bisoleylamide, N-stearyl stearic acid amide, and N-stearyl erucic acid amide.

[0160] These higher fatty acids, higher fatty acid metal salts, higher fatty acid esters and higher fatty acid amides may be used either alone or in combination of two or more.

[0161] The content of the lubricant in the polyamide 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 100% by mass of the total mass of the polyamide composition. When the content of the lubricant is equal to or more than the lower limit, the moldability of the polyamide composition can be improved, while when the content is equal to or less than the upper limit, the rigidity of the molded product can be improved.

[0162] [Heat Stabilizer] Examples of the 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.

[0163] (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.

[0164] 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, and 1,3,5-tris(4-tert-butyl-3-hydroxy-2,6-dimethylbenzyl)isocyanuric acid. 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.

[0165] When a phenolic heat stabilizer is used, the content of the phenolic heat stabilizer in the polyamide 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 100% by mass of the total mass of the polyamide composition. When the content of the phenolic heat stabilizer is within the above range, the heat aging resistance of the polyamide composition can be further improved and the amount of gas generation can be further reduced.

[0166] (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 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.

[0167] 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 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.

[0168] When a phosphorus-based heat stabilizer is used, the content of the phosphorus-based heat stabilizer in the polyamide 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 100% by mass of the total mass of the polyamide composition. When the content of the phosphorus-based heat stabilizer is within the above range, the heat aging resistance of the polyamide composition can be further improved and the amount of gas generation can be further reduced.

[0169] (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,and condensates of a compound selected from the group consisting of [5-di-tert-butyl-4-hydroxyphenyl)propionyloxy]2,2,6,6-tetramethylpiperidine and 1,2,3,4-butanetetracarboxylic acid with a compound selected from the group consisting of 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. These amine-based heat stabilizers may be used alone or in combination of two or more.

[0170] When an amine-based heat stabilizer is used, the content of the amine-based heat stabilizer in the polyamide 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 100% by mass of the total mass of the polyamide composition. When the content of the amine-based heat stabilizer is within the above range, the heat aging resistance of the polyamide composition can be further improved, and the amount of gas generation can be further reduced.

[0171] Among these, 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 composition can be obtained that 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").

[0172] When a copper salt is used as a heat stabilizer, the content of the copper salt in the polyamide composition is preferably 0.01% by mass or more and 0.60% by mass or less, and more preferably 0.02% by mass or more and 0.40% by mass or less, relative to the total mass of the polyamides (crystalline polyamide (A-1) and amorphous polyamide (A-2)). When the content of the copper salt is within the above range, the heat aging resistance of the polyamide composition can be further improved, and copper precipitation and metal corrosion can be more effectively suppressed.

[0173] In addition, the content of copper element derived from the copper salt is set to 100% by weight of polyamide ((A-1) crystalline polyamide and (A-2) amorphous polyamide) from the viewpoint of improving the heat aging resistance of the polyamide composition. ６ The 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.

[0174] (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, and the like.

[0175] These alkali metal and alkaline earth metal halides may be used alone or in combination of two or more. Among them, from the viewpoint of improving heat aging resistance and suppressing metal corrosion, the alkali metal and alkaline earth metal halides are preferably at least one selected from the group consisting of potassium iodide and potassium bromide, and more preferably potassium iodide.

[0176] When alkali metal and alkaline earth metal halides are used, the content of the alkali metal and alkaline earth metal halides in the polyamide composition is preferably 0.05 parts by mass or more, more preferably 0.2 parts by mass or more, and preferably 20 parts by mass or less, more preferably 10 parts by mass or less, per 100 parts by mass of polyamide (crystalline polyamide (A-1) and amorphous polyamide (A-2)). When the content of the alkali metal and alkaline earth metal halides is within the above range, the heat aging resistance of the polyamide composition is further improved, and copper precipitation and metal corrosion can be more effectively suppressed.

[0177] The heat stabilizer components described above may be used alone or in combination of two or more. Among them, a hindered phenol compound is preferred as the heat stabilizer from the viewpoint of further improving the heat aging resistance of the polyamide composition.

[0178] [Nucleating Agent] A nucleating agent is 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 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.

[0179] Examples of nucleating agents include, but are not limited to, talc, boron nitride, mica, kaolin, silicon nitride, potassium titanate, molybdenum disulfide, etc. The nucleating agents may be used alone or in combination of two or more. Among them, talc or boron nitride is preferred as the nucleating agent from the viewpoint of nucleating agent effect.

[0180] Furthermore, because the nucleating agent is highly effective, the number average particle size of the nucleating agent is preferably 0.01 μm or more and 10 μm or less. The number average particle size of the nucleating agent can be measured using the following method. First, the molded product 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 size can be determined by observing the product with an optical microscope, a scanning electron microscope, or the like, and measuring the particle size.

[0181] The content of the nucleating agent in the polyamide 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 100% by mass of the total mass of the polyamide composition. By setting the content of the nucleating agent to be equal to or more than the above lower limit, the heat resistance of the polyamide composition tends to be further improved, and by setting the content of the nucleating agent to be equal to or less than the above upper limit, a polyamide composition with superior toughness can be obtained.

[0182] [Other Polymers] The other polymers are not particularly limited as long as they are not polyamides, and examples thereof include polyester, liquid crystal polyester, polyphenylene sulfide, polyphenylene ether, polycarbonate, polyarylate, phenol resin, epoxy resin, etc. Examples of polyesters include, but are not limited to, polybutylene terephthalate, polytrimethylene terephthalate, polyethylene terephthalate, polyethylene naphthalate, etc.

[0183] The content of the other polymer is preferably 1% by mass or more and 30% by mass or less, more preferably 5% by mass or more and 20% by mass or less, and even more preferably 5% by mass or more and 15% by mass or less, based on the total amount of polyamide in the polyamide composition. When the content of the other polymer is within the above range, the polyamide composition can have better heat resistance and mold releasability.

[0184] [Other Additives] In addition to the above-described components, the polyamide composition obtained by the production method of this embodiment may contain other additives commonly used in polyamide compositions, provided that the effects of the polyamide composition obtained by the production method of this embodiment are not impaired. Examples of other additives include colorants such as pigments and dyes (including colored masterbatches), flame retardants, fibrillating agents, fluorescent bleaching agents, plasticizers, antioxidants, UV absorbers, antistatic agents, flow improvers, and spreading agents.

[0185] When the polyamide composition obtained by the production method of the present embodiment contains other additives, the content of the other additives varies depending on the type of additive and the use of the polyamide composition, and is not particularly limited as long as it is within a range that does not impair the effects of the polyamide composition obtained by the production method of the present embodiment.

[0186] <Method for producing polyamide composition> The method for producing the polyamide composition of this embodiment is not particularly limited as long as it includes a step of melt-kneading raw material components including the above-mentioned (A) polyamide, (B) phosphorus-based flame retardant, and (C) inorganic filler. For example, a method including a step of melt-kneading raw material components including the above-mentioned (A) polyamide, (B) phosphorus-based flame retardant, and (C) inorganic filler in an extruder, in which the set temperature of the extruder is set to not more than the melting peak temperature (Tm) of the above-mentioned polyamide composition + 30°C, is preferred.

[0187] Examples of methods for melt-kneading raw material components containing polyamide include a method in which (A) polyamide and (D) other raw materials are mixed using a tumbler, a Henschel mixer, or the like, and the mixture is fed into a melt-kneader and kneaded therein; and a method in which (B) other raw materials including a phosphorus-based flame retardant and (C) an inorganic filler are blended from a side feeder into the (A) polyamide that has been molten in a single-screw or twin-screw extruder.

[0188] The components constituting the polyamide 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.

[0189] The melt-kneading temperature is preferably about 250°C or higher and 350°C or lower in terms of resin temperature. The melt-kneading time is preferably about 0.25 minutes or higher and 5 minutes or lower. The melt-kneading device is not particularly limited, and known melt-kneaders such as single-screw or twin-screw extruders, Banbury mixers, and mixing rolls can be used. The melt-kneader is preferably a co-rotating twin-screw extruder with a screw diameter of 30 mm or higher, and the ratio (L / D) of the barrel length (L) to the screw diameter (D) of the twin-screw extruder is preferably 35 or higher. By setting the L / D of the extruder within the above range, appropriate kneading can be achieved during kneading without significant heat generation, and the domain diameter of the amorphous polyamide can be adjusted to the preferred range in this application. In the twin-screw extruder, the screw rotation speed (N) is preferably 350 rpm or higher, and the ratio Q / N of the screw rotation speed (N) to the discharge rate (Q) is preferably 1.14 or lower. When the Q / N is within the above range, appropriate kneading can be performed during kneading without generating significant heat, and the domain diameter of the amorphous polyamide can be adjusted to the preferred range in the present application. Furthermore, when adding the phosphorus-based flame retardant (B) and the inorganic filler (C), since the phosphorus-based flame retardant (B) and the inorganic filler (C) improve the kneading efficiency, it is preferable to dry-blend the polyamide (A) and then feed the polyamide (A) from the upstream feed port of the twin-screw extruder, and then feed the phosphorus-based flame retardant (B) and the inorganic filler (C) from the downstream first feed port of the twin-screw extruder.

[0190] <Molded Article> The molded article of the present embodiment is obtained by molding the polyamide composition described above.

[0191] The molded article of the present embodiment uses the above-described polyamide composition, and therefore has excellent low-temperature impact resistance, deflection temperature under load, electrical properties, and flame retardancy.

[0192] The molded article of the present embodiment can be obtained by molding the above-mentioned polyamide composition using a well-known molding method, such as press molding, injection molding, gas-assisted injection molding, welding molding, extrusion molding, blow molding, film molding, blow molding, multi-layer molding, melt spinning, etc.

[0193] The polyamide composition of the present embodiment can be used in applications where heat resistance, flame retardancy, and electrical properties are particularly important, and is suitable for electrical and electronic components and automotive electrical and electronic components. Examples of such electrical components include industrial equipment such as office machines, measuring instruments, chassis, internal parts of electrical equipment, power adapters for home appliances, recording media and their drives, sensor devices, terminal blocks, secondary batteries in the energy and environmental fields, electrical and electronic components used in fuel cells, solar cells, solar thermal power generation, geothermal power generation, wind power generation, smart meters, and the like, electrical components constituting power transmission facilities, cable terminals, and automotive components, particularly connection structures for photovoltaic power generation modules such as photovoltaic power generation module connectors and solar cell junction boxes, and components for hybrid and electric vehicles.

[0194] The present invention will be described below with reference to examples, but the present invention is not limited to the following examples.

[0195] 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.

[0196] <Constituent Components> [(A) Polyamide] A-1: ​​Polyamide 66 (synthesized by the method described below) A-2: Polyamide 6I (synthesized by the synthesis method described below)

[0197] [(B) Phosphorus-based flame retardants] (B-1) Phosphinic acid flame retardant: aluminum complex salt of diethylphosphinic acid and ethylphosphonic acid (manufactured by Weihaijun Co., Ltd., trade name "MADP8900SP", bulk specific gravity 0.59 g / mL, flake shape, collapse strength 35N) (B-2) Phosphinic acid flame retardant: aluminum complex salt of diethylphosphinic acid and ethylphosphonic acid (manufactured by Weihaijun Co., Ltd., trade name "MADP8900BP", bulk specific gravity 0.65 g / mL, cylindrical shape, collapse strength 9N) (B-3) Phosphinic acid flame retardant: aluminum complex salt of diethylphosphinic acid and ethylphosphonic acid (manufactured by Weihaijun Co., Ltd., trade name "HR8900", bulk specific gravity 0.34 g / mL, powder) (B-4) Phosphinic acid flame retardant: aluminum diethylphosphinate (manufactured by Clariant, trade name "Exolit OP1230 (bulk specific gravity 0.52 g / mL, powder)

[0198] [(C) Inorganic Filler] C-1: Glass fiber (GF) (manufactured by Nippon Electric Glass Co., Ltd., product name "ECS03T275H", average fiber diameter 10 μmφ, cut length 3 mm)

[0199] [Other flame retardants] (D) Anhydrous zinc borate (Firebrake 500 manufactured by Kinseimatic Co., Ltd.)

[0200] <Production of Polyamide> The production methods for crystalline polyamide A-1 and amorphous polyamide A-2 are described in detail below. Crystalline polyamide A-1 and amorphous polyamide A-2 obtained by the production methods described below were dried in a nitrogen stream to adjust the moisture content to about 0.2 mass % before being used as raw materials for polyamide compositions in the examples and comparative examples described below.

[0201] Synthesis Example 1 Synthesis of Crystalline Polyamide A-1 (Polyamide 66) A polyamide polymerization reaction was carried out by the "hot melt polymerization method" as follows. First, 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 of 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 approximately 110°C to 150°C. Next, 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 maintained at a reduced pressure of 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), which were then water-cooled, cut, and discharged in pellet form. The pellets were then dried at 100°C under a nitrogen atmosphere for 12 hours to obtain crystalline polyamide A-1 (polyamide 66). The resulting crystalline polyamide A-1 (polyamide 66) had an Mw(A) of 40,000, an Mw / Mn of 2.0, and a melting point (Tm) of 260°C.

[0202] [Synthesis Example 2] (Synthesis of Amorphous Polyamide A-2 (Polyamide 6I)) A polyamide polymerization reaction was carried out by the "hot melt polymerization method" as follows. First, 1500 g of an equimolar salt of isophthalic acid and hexamethylenediamine, a 1.5 mol % excess adipic acid relative to the total equimolar salt components, and 0.5 mol % acetic acid were dissolved in 1500 g of distilled water to prepare a 50 mass% equimolar homogeneous aqueous solution of the raw material monomers. Next, while stirring at a temperature of approximately 110°C to 150°C, the solution was concentrated by gradually removing steam to a solution concentration of 70 mass%. Next, the internal temperature was raised to 220°C. At this time, the autoclave was pressurized to 1.8 MPa. The reaction was continued 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 30 minutes. The autoclave was then maintained at a reduced pressure of 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), which were then water-cooled, cut, and discharged in pellet form. The pellets were then dried at 100°C under a nitrogen atmosphere for 12 hours to obtain amorphous polyamide A-2 (polyamide 6I). The resulting amorphous polyamide A-2 (polyamide 6I) had a content of isophthalic acid units in the dicarboxylic acid units of 100 mol%. Mw(B) = 20,000, Mw / Mn = 2.0.

[0203] <Methods for Measuring Physical Properties> The following physical properties were measured using the raw material polyamide and the polyamide composition after adjusting the water content.

[0204] [Physical Property 1] (Molecular Weight and Molecular Weight Distribution of Polyamide Composition) Mw (weight average molecular weight) and Mn (number average molecular weight) were measured using a gel permeation chromatograph (GPC) (HLC-8020, manufactured by Tosoh Corporation) and a hexafluoroisopropanol solvent, converted into a PMMA (polymethyl methacrylate) standard sample (manufactured by Polymer Laboratory Co., Ltd.) From the values, the molecular weight distribution Mw / Mn was calculated.

[0205] [Physical Property 2] (Melting Peak Temperature Tm (Melting Point)) Measurement was carried out in accordance with JIS-K7121 using a Diamond-DSC manufactured by Perkin-Elmer. Specifically, the measurement was carried out as follows. First, in a nitrogen atmosphere, about 10 mg of a sample was heated from room temperature to 300°C or higher and 350°C or lower depending on the melting point of 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 taken as Tm (°C).

[0206] [Physical Property 3] (Glass Transition Temperature Tg) The glass transition temperature Tg (°C) was measured in accordance with JIS-K7121 using a Diamond-DSC manufactured by Perkin-Elmer. The measurement conditions were as follows: the polyamide was melted on a hot stage (EP80 manufactured by Mettler), and the resulting molten sample was rapidly cooled using liquid nitrogen to solidify it, thereby obtaining a measurement sample. 10 mg of this sample was heated at a heating rate of 20°C / min from 30°C to 350°C, and the glass transition temperature Tg (°C) was measured.

[0207] Details of the raw materials are as follows:

[0208] (Thermoplastic resin) Polyamide (PA): Crystalline polyamide A-1 (polyamide 66) Amorphous polyamide A-2 (polyamide 6I)

[0209] (Flame Retardants) (B-1) Phosphinic Acid Flame Retardant Aluminum complex salt of diethylphosphinic acid and ethylphosphonic acid (manufactured by Weihaijun Co., Ltd., trade name "MADP8900SP", bulk specific gravity 0.59 g / mL, flake shape, collapse strength 35N) (B-2) Phosphinic Acid Flame Retardant Aluminum complex salt of diethylphosphinic acid and ethylphosphonic acid (manufactured by Weihaijun Co., Ltd., trade name "MADP8900BS", bulk specific gravity 0.65 g / mL, cylindrical shape, collapse strength 9N) (B-3) Phosphinic Acid Flame Retardant Aluminum complex salt of diethylphosphinic acid and ethylphosphonic acid (manufactured by Weihaijun Co., Ltd., trade name "HR8900", bulk specific gravity 0.34 g / mL, powder) (B-4) Phosphinic Acid Flame Retardant Aluminum diethylphosphinate (manufactured by Clariant, trade name "Exolit OP1230 (bulk specific gravity 0.52 g / mL, powder)

[0210] (Inorganic filler) Inorganic filler: Inorganic filler C-1 (glass fiber (GF) (manufactured by Nippon Electric Glass Co., Ltd., product name "ECS03T275H", average fiber diameter 10 μmφ, cut length 3 mm))

[0211] (Other Components) (D) Anhydrous Zinc Borate [Evaluation 1] (Tensile Strength) Pellets of each polyamide composition were molded into ISO 3167, multipurpose test piece Type A using an injection molding machine [PS-40E: manufactured by Nissei Plastics Co., Ltd.] with an injection + dwell time of 25 seconds, a cooling time of 15 seconds, a mold temperature of 80°C, and a molten resin temperature of 270°C. Using the obtained molded piece, a tensile test was carried out in accordance with ISO 527 at a pulling rate of 5 mm / min, and the tensile strength (MPa) was calculated.

[0212] [Evaluation 2] <Metal Corrosion> 20 g of the pellets obtained in the Examples and Comparative Examples were placed in a 2.0 MPa pressure-resistant, 100 mL SUS314 autoclave. A carbon steel (SS400) test piece measuring 10 mm x 20 mm x 2.0 mm in length, width, and thickness and having a surface polished with #2000 grit was placed inside the autoclave, and 20 g of pellets were added to bury the carbon steel test piece. The autoclave was then purged with nitrogen, sealed, and placed in a thermostatic chamber set at 320°C for 6 hours. The autoclave was then removed under running water, cooled to room temperature, and opened. The carbon steel test piece was removed from the melted and solidified pellets, and the resin adhering to the carbon steel test piece was dissolved and removed with toluene. The carbon steel test piece was air-dried and weighed to the nearest 0.1 mg. This was divided by the pre-measured weight of the carbon steel test piece before the corrosion test to determine the weight loss rate before and after the test in ppm by mass.

[0213] [Evaluation 3] <Weld Strength> A test specimen was obtained by molding a 127 mm long, 12.7 mm wide, and 1.6 mm thick specimen using an injection molding machine (PS40E manufactured by Nissei Plastic Industrial Co., Ltd.) equipped with a mold in which molten resin flowed from both longitudinal ends to form a weld in the longitudinal center. The molded test specimen was subjected to a tensile test according to ISO 527, except that the chuck distance was 50 mm and the tensile speed was 5 mm / min, to determine the tensile strength. The measured value was the average of n = 6.

[0214] [Evaluation 4] <Flame Retardancy> Measurements were carried out using the method of UL94 (a standard established by Under Writers Laboratories Inc., USA). Test specimens (length 127 mm, width 12.7 mm, thickness 0.75 mm and length 127 mm, width 12.7 mm, thickness 1.50 mm) were prepared by attaching a UL test specimen mold (mold temperature = 100°C) to an injection molding machine (PS40E manufactured by Nissei Kogyo Co., Ltd.) and molding each polyamide composition at a cylinder temperature of 290°C. The injection pressure was set at the full filling pressure + 2% when molding the UL test specimen. The flame retardancy grade was evaluated according to the UL94 standard (vertical flame test) to determine whether the specimen was classified as V-0, V-1, or V-2. The smaller the grade, the higher the flame retardancy.

[0215] [Evaluation 5] <Dispersed Particle Diameter of Flame Retardant> The dispersed particle diameter of the flame retardant was measured using a digital microscope (Keyence Corporation, "VHX-8000"). Sample: Pellets of the polyamide composition were embedded in epoxy resin, and the cross-section of the pellet was polished using a benchtop polisher (IM-P2 / SP-L1, IMT Corporation), then fixed to a sample stage and coated with Os. This sample was observed at 300x magnification using a digital microscope to determine the presence of the phosphorus-based flame retardant (B) within an 800 μm x 800 μm square. Here, if the number of particles within the 800 μm x 800 μm square field of view was less than 300, the observation was performed at a magnification that resulted in a particle count of 500 or more. The phosphorus-based flame retardant (B) was subjected to binarization processing using Python and image analysis. The median diameter (D50) corresponding to 50% of the smallest particle diameters, and the ratio (d75 / d25) of the particle diameter (d25) of the particles corresponding to 25% (number of particles) of the smallest particle diameters to the particle diameter (d75) of the particles corresponding to 75% (number of particles) of the smallest particle diameters were calculated.

[0216] [Extrusion Operation Stability] When the polyamide compositions of the Examples and Comparative Examples were produced using a twin-screw extruder, the torque fluctuation of the extruder after 15 minutes of operation was evaluated as an index of operation stability based on the following criteria: A: Torque fluctuation range is less than 3% B: Torque fluctuation range is 3% or more and less than 6% C: Torque fluctuation range is 6% or more and less than 10% D: Torque fluctuation range is 10% or more.

[0217] [Molding fluidity spiral flow length; SFD] Pellets of each polyamide composition were injection molded using an injection molding machine (Nissei Plastic Industrial Co., Ltd. NEX50IV) under conditions of a cylinder temperature of 290°C, a mold temperature of 80°C, injection for 10 seconds, cooling for 10 seconds, and an injection speed of 100 mm / s, and molded in a spiral flow mold with a width of 10 mm and a thickness of 2 mm. The flow length (spiral flow length; SFD) was measured when the limit pressure was set to 70 MPa. The longer the measured flow length (spiral flow length; SFD), the better the molding fluidity.

[0218] <Production of Polyamide Compositions> [Examples 1 to 6 and Comparative Examples 1 to 6] (Production of Polyamide Compositions PA-a1 to PA-a7 and PA-b1 to PA-b6) Polyamide compositions were produced as follows using (A) polyamide, (B) flame retardant, and (C) inorganic filler in the types and proportions shown in the tables below.

[0219] The raw material polyamide (A) was dried in a nitrogen stream to adjust the moisture content to about 0.2% by mass before being used as a raw material for the polyamide composition.

[0220] As the apparatus for producing the polyamide composition, a twin-screw extruder (manufactured by Toshiba Machine Co., Ltd., trade name "TEM-58SS") was used.

[0221] In the twin-screw extruder, the temperature from the upstream feed port to the die was set to the melting point Tm of each (A) crystalline polyamide produced in the above production example + 20°C, the screw rotation speed was set to 350 rpm, and the discharge rate was set to 400 kg / h (Q / N = 1.14). The extruder screw was provided with three kneading blocks. The first kneading block was provided in the third barrel of the extruder, and the second kneading block was provided in the sixth barrel of the extruder. The third kneading block was provided in the eighth barrel of the extruder. Here, the "kneading block" refers to a block consisting of multiple consecutive screw elements called kneading disks, which have a high kneading effect. Next, the polymer was discharged in the form of a strand from the extruder tip nozzle, and after measuring the resin temperature, it was water-cooled and cut to obtain pellets of the polyamide composition.

[0222] (A) Polyamide was dry-blended to the types and ratios shown in the tables below, and then fed from the upstream feed port (TOP) of a twin-screw extruder. (B) Flame retardant was fed from the upstream feed port (TOP) or the first downstream feed port (SIDE 1) of the twin-screw extruder, and (C) Glass fiber was fed from the second downstream feed port (SIDE 2). The strand-like molten mixture extruded from the die head was cooled and pelletized to obtain pellets of the polyamide composition. The pellets of the polyamide composition thus obtained were dried in a nitrogen stream to reduce the moisture content in the polyamide composition to 500 ppm or less.

[0223]

[0224] As can be seen from Table 1, the compositions containing (A) polyamide, (B) flame retardant, and (C) inorganic filler in the specified amounts maintained the flame retardancy of UL94 V-0 and were excellent in weld strength, tensile strength, metal corrosion resistance, flowability, operating stability, and molding flowability.

[0225] Having the above-mentioned properties, the composition can be suitably used in electrical and electronic parts, and electrical and electronic parts for automobiles.

[0226] According to the polyamide composition of the present embodiment, a polyamide composition having excellent flame retardancy can be provided.

Claims

1. A polyamide composition comprising, relative to 100% by mass of the total mass of the polyamide composition, 20-60% by mass of (A) polyamide, 10-30% by mass of (B) phosphorus-based flame retardant, and 10-60% by mass of (C) inorganic filler, wherein the (B) phosphorus-based flame retardant comprises at least one phosphinic acid-phosphonic acid complex metal salt selected from the group consisting of condensates of phosphinic acid-phosphonic acid complex metal salts represented by the following general formula (1): (In general formula (1), R １ , R ２ , and R ３ each independently represents an alkyl group having 1 to 6 carbon atoms or an aryl group having 6 to 10 carbon atoms; M ｍ＋ is a metal ion, M is an element belonging to Group 2 or 15 of the Periodic Table, a transition element, zinc, aluminum, or a combination thereof, m is 2 to 3, R １ and R ２ If there are multiple R １ and R ２ may be the same or different.) A polyamide composition, wherein the median diameter (D50) of the phosphorus-based flame retardant (B) observed in the polyamide composition or a molded article obtained by molding the polyamide composition is 2.5 to 6.0 μm, and the ratio (d75 / d25) of the particle diameter (d25) of the smallest 25% (number of particles) of particles to the particle diameter (d75) of the smallest 75% (number of particles) of particles is less than 2.

0.

2. The polyamide composition of claim 1, wherein M is aluminum.

3. The polyamide composition according to claim 1 or 2, wherein the polyamide (A) comprises a crystalline polyamide (A-1).

4. The polyamide composition according to claim 3, wherein the polyamide (A) further comprises an amorphous polyamide (A-2), the amorphous polyamide (A-2) is a polyamide containing dicarboxylic acid units and diamine units, and contains 50 mol % or more of isophthalic acid units among all dicarboxylic acid units constituting the amorphous polyamide (A-2).

5. The polyamide composition according to claim 4, wherein the (A-2) amorphous polyamide contains isophthalic acid units in an amount of 75 mol % or more of all dicarboxylic acid units constituting the polyamide.

6. The polyamide composition according to claim 5, wherein the amorphous polyamide (A-2) contains 100 mol % of isophthalic acid units in all dicarboxylic acid units constituting the amorphous polyamide.

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

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