JP7548752B2 - Polyamide composition, its manufacturing method, and molded article - Google Patents

Description

The present invention relates to a polyamide composition, a method for producing the same, and a molded article.

Due to their outstanding property profile, compositions based on aliphatic polyamides are used to produce moldings in a great many applications. Polyamide compositions with flame retardant properties are required in particular for components in the electrical and electronics industry to ensure adequate fire protection.

Polyamides are often flame retarded by the addition of flame retardants, such as phosphorus compounds. Patent document 1 discloses the use of calcium and aluminum salts of phosphinic or diphosphinic acids as flame retardants for polyamides. Test specimens with a sample thickness of 1.2 mm made from polyamide compositions containing these phosphinic flame retardants and reinforced with 30% by weight of glass fiber based on the total weight of the composition achieve a flammability classification of V-0 according to UL94.

Patent Document 2 discloses that, in order to achieve UL94 flammability classification V-0, aluminum phosphinate is required in an amount far exceeding 20 mass % relative to the total mass of the composition in a glass fiber reinforced polyamide composition mainly composed of polyamide 6, and in an amount exceeding 30 mass % in a glass fiber reinforced polyamide composition mainly composed of polyamide 66. Thus, in order to achieve flammability classification V-0 using a phosphinic acid flame retardant, a large amount must be added, which creates the problem of adversely affecting mechanical properties.

Patent Document 3 discloses a polyamide composition based on a mixture of an aliphatic polyamide containing a phosphinate salt as a flame retardant and a semi-aromatic polyamide. It has been reported that the addition of the semi-aromatic polyamide reduces the amount of flame retardant used and improves tensile elongation.

Patent Document 4 discloses a polyamide composition based on a mixture of polyamides, including aromatic polyamides, and polyphenylene sulfide, using a phosphinate as a flame retardant. It has been reported that the amount of flame retardant used can be reduced by adding polyphenylene sulfide, which has excellent flame retardancy, to polyamides, including aromatic polyamides, and that the amount of outgassing derived from the flame retardant can be reduced.

Patent No. 3947261 Patent No. 4698789 Patent No. 4614959 JP 2009-270107 A JP 2005-179362 A European Patent Application Publication No. 699708 Japanese Patent Application Publication No. 08-073720

However, in the polyamide composition described in Patent Document 3, the tensile elongation at break is improved by reducing the amount of flame retardant used, and in the polyamide composition described in Patent Document 4, the amount of outgassing derived from the flame retardant can be reduced, but there is still room for improvement in long-term heat resistance, creep characteristics, and the like, which are required for automobiles and various electric parts.
Thus, in the prior art, no polyamide composition having excellent flame retardancy, long-term heat resistance and good creep properties has yet been known.

The present invention has been made in consideration of the above circumstances, and provides a polyamide composition that has excellent flame retardancy and, when made into a molded article, good long-term heat resistance and creep properties, a method for producing the same, and a molded article made of the polyamide composition.

That is, the present invention includes the following aspects.
The polyamide composition according to the first aspect of the present invention is a polyamide composition containing (A) an aliphatic polyamide, (B) a semi-aromatic polyamide containing a diamine unit and a dicarboxylic acid unit, (C) a flame retardant, (D) a styrene-acrylonitrile copolymer or a polymer containing a styrene-acrylonitrile copolymer and an α,β-unsaturated dicarboxylic acid anhydride as a constituent unit , and (E) a polyhydric alcohol, wherein the mass ratio (E)/(D) of the content of the polyhydric alcohol (E) to the content of the (D) styrene-acrylonitrile copolymer or the polymer containing a styrene-acrylonitrile copolymer and an α,β-unsaturated dicarboxylic acid anhydride as a constituent unit is 0.25 or more and less than 2.00, the styrene-acrylonitrile copolymer contains a styrene unit and an acrylonitrile unit, and the content of the acrylonitrile unit is 30 mass% or more with respect to the total mass of the constituent units of the styrene-acrylonitrile copolymer .
The (E) polyhydric alcohol may be at least one selected from the group consisting of tripentaerythritol, dipentaerythritol, and pentaerythritol.
The (C) flame retardant may be a phosphorus-based flame retardant.
The (C) flame retardant may contain at least one phosphinate selected from the group consisting of a phosphinate represented by the following general formula (1), a diphosphinate represented by the following general formula (2), and a condensate thereof:

(In general formula (1), R ¹¹ and R ¹² each independently represent an alkyl group having 1 to 6 carbon atoms or an aryl group having 6 to 10 carbon atoms. M ⁿ¹¹⁺ represents a metal ion having a valence of n11. M represents an element belonging to Group 2 or Group 15 of the periodic table or a transition element. n11 is 2 or 3. When n11 is 2 or 3, a plurality of R ¹¹ and R ¹² may be the same or different.
In the general formula (2), R ²¹ and R ²² are each independently an alkyl group having 1 to 6 carbon atoms, or an aryl group having 6 to 10 carbon atoms. Y ²¹ is an alkylene group having 1 to 10 carbon atoms, or an arylene group having 6 to 10 carbon atoms. M' ^m21+ is a metal ion having a valence of m21. M' is an element or a transition element belonging to Group 2 or Group 15 of the periodic table. n21 is an integer of 1 to 3. When n21 is 2 or 3, the multiple R ²¹ , R ²² , and Y ²¹ may be the same or different. m21 is 2 or 3. x is 1 or 2. When x is 2, the multiple M' may be the same or different. n21, x, and m21 are integers that satisfy the relationship formula 2×n21=m21×x.)

The content of the (C) flame retardant may be 0.1 mass % or more and 30 mass % or less based on the mass of the polyamide composition.
The (D) styrene-acrylonitrile copolymer, or the polymer containing a styrene-acrylonitrile copolymer and an α,β-unsaturated dicarboxylic acid anhydride as a constituent unit, may include a polymer containing an α,β-unsaturated dicarboxylic acid anhydride as a constituent unit, and the polymer containing an α,β-unsaturated dicarboxylic acid anhydride as a constituent unit may be maleic anhydride-modified polyphenylene ether .
The (A) aliphatic polyamide may contain a diamine unit and a dicarboxylic acid unit.
The aliphatic polyamide (A) may be polyamide 66.
The polyamide composition may have a tan δ peak temperature of 90° C. or higher.
The semi-aromatic polyamide containing (B) diamine units and dicarboxylic acid units may contain 50 mol % or more of isophthalic acid units among all dicarboxylic acid units constituting the semi-aromatic polyamide containing (B) diamine units and dicarboxylic acid units.
The semi-aromatic polyamide containing (B) diamine units and dicarboxylic acid units may contain 75 mol % or more of isophthalic acid units among all dicarboxylic acid units constituting the semi-aromatic polyamide containing (B) diamine units and dicarboxylic acid units.
The semi-aromatic polyamide containing (B) diamine units and dicarboxylic acid units may contain 100 mol % of isophthalic acid units in all dicarboxylic acid units constituting the semi-aromatic polyamide containing (B) diamine units and dicarboxylic acid units.
The polyamide composition may have a weight average molecular weight of 10,000 or more and 50,000 or less.
The polyamide composition according to the first aspect may further comprise at least one type of (F) filler.

The molded article according to the second aspect of the present invention is produced by molding the polyamide composition according to the first aspect.

The method for producing a polyamide composition according to the third aspect of the present invention is a method for producing a polyamide composition according to the first aspect, in which raw material components including (A) an aliphatic polyamide, (B) a semi-aromatic polyamide containing diamine units and dicarboxylic acid units, (C) a flame retardant, (D) a polymer containing an α,β-unsaturated dicarboxylic anhydride as a constituent unit and/or a styrene-acrylonitrile copolymer, and (E) a polyhydric alcohol are melt-kneaded.

The polyamide composition and the method for producing the same of the above aspect can produce a molded article having excellent flame retardancy, long-term heat resistance, and good creep properties. The molded article of the above aspect has excellent flame retardancy, long-term heat resistance, and good creep properties.

The following describes in detail the form for carrying out the present invention (hereinafter, simply referred to as the "present embodiment"). 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 with appropriate modifications within the scope of its gist.

In this specification, "polyamide" refers to a polymer that has amide (-NHCO-) groups in the main chain.

<Polyamide composition>
The polyamide composition of the present embodiment contains the following components (A) to (E).
(A) an aliphatic polyamide;
(B) a semi-aromatic polyamide containing diamine units and dicarboxylic acid units;
(C) a flame retardant;
(D) a polymer containing an α,β-unsaturated dicarboxylic acid anhydride as a constituent unit and/or a styrene-acrylonitrile copolymer; and (E) a polyhydric alcohol.

In the polyamide composition of the present embodiment, the mass ratio (E)/(D) of the content of the polyhydric alcohol (E) to the content of the polymer containing an α,β-unsaturated dicarboxylic anhydride as a constituent unit (D) and/or the styrene-acrylonitrile copolymer is 0.25 or more and less than 2.00, preferably 0.25 or more and 1.80 or less, more preferably 0.25 or more and 1.50 or less, even more preferably 0.30 or more and 1.00 or less, and particularly preferably 0.40 or more and 0.80 or less.
When the mass ratio (E)/(D) is equal to or greater than the above lower limit, the composition has better long-term heat resistance, whereas when the mass ratio (E)/(D) is less than the above upper limit, the composition tends to have better moldability, appearance, flame retardancy, and creep properties.

The polyamide composition of this embodiment has the above-mentioned configuration, and thus produces molded products with excellent flame retardancy, long-term heat resistance, and good creep properties.

<Characteristics of polyamide composition>
The molecular weight and tan δ peak temperature of the polyamide composition of the present embodiment can be as follows, and specifically, can be measured by the method described in the examples described later.

[Weight average molecular weight (Mw) of polyamide composition]
The weight average molecular weight (Mw) can be used as an indicator of the molecular weight of a polyamide composition.
The weight average molecular weight (Mw) of the polyamide composition is preferably 10,000 or more and 50,000 or less, more preferably 15,000 or more and 45,000 or less, even more preferably 20,000 or more and 45,000 or less, even more preferably 25,000 or more and 42,000 or less, particularly preferably 25,000 or more and 40,000 or less, and most preferably 25,000 or more and 35,000 or less.
When the weight-average molecular weight (Mw) of the polyamide composition is within the above range, a polyamide having excellent mechanical properties, particularly excellent rigidity upon absorption of water, rigidity upon heating, flowability, etc. Furthermore, a molded article obtained from a polyamide composition containing a component such as a filler has excellent tensile strength, flexural modulus upon absorption of water, long-term heat resistance, and aging characteristics.

Examples of methods for controlling the Mw of the polyamide composition within the above range include using (A) an aliphatic polyamide, (B) a semi-aromatic polyamide, and (D) a polymer containing an α,β-unsaturated dicarboxylic acid anhydride as a structural unit, each of which has an Mw within the range described below.
The weight average molecular weight (Mw) can be measured by gel permeation chromatography (GPC) as described in the Examples below.

[Tan δ peak temperature of polyamide composition]
The lower limit of the tan δ peak temperature of the polyamide composition is preferably 90°C, more preferably 105°C, and even more preferably 110°C.
On the other hand, the upper limit of the tan δ peak temperature of the polyamide composition is preferably 150°C, more preferably 140°C, and even more preferably 130°C.
That is, the tan δ peak temperature of the polyamide composition is preferably 90°C or higher, more preferably 105°C or higher and 150°C or lower, further preferably 110°C or higher and 140°C or lower, and particularly preferably 110°C or higher and 130°C or lower.
When the tan δ peak temperature of the polyamide composition is equal to or higher than the lower limit, the polyamide composition tends to have excellent water absorption rigidity and hot rigidity. On the other hand, when the tan δ peak temperature of the polyamide composition is equal to or lower than the upper limit, the molded article obtained from the polyamide composition containing a component represented by a filler tends to have excellent tensile strength, flexural modulus when absorbing water, long-term heat resistance, and creep characteristics.

Examples of methods for controlling the tan δ peak temperature of the polyamide composition within the above range include a method for controlling the content of (A) aliphatic polyamide and (B) semi-aromatic polyamide within the range described below.

<Constituents of polyamide composition>
Hereinafter, each of the components of the polyamide composition of the present embodiment will be described in detail.

[(A) Aliphatic polyamide]
The structural units of the aliphatic polyamide (A) preferably satisfy at least one of the following conditions (1) and (2).
(1) The polymer contains (Aa) an aliphatic dicarboxylic acid unit and (Ab) an aliphatic diamine unit.
(2) (Ac) Contains at least one unit selected from the group consisting of lactam units and aminocarboxylic acid units.

The polyamide composition of this embodiment may contain, as the aliphatic polyamide (A), one or more polyamides that satisfy at least one of the above conditions (1) and (2). In particular, it is particularly preferable that the structural unit of the aliphatic polyamide (A) contained in the polyamide composition of this embodiment satisfies the above condition (1).

((A-a) Aliphatic Dicarboxylic Acid Unit)
Examples of the aliphatic dicarboxylic acid constituting the aliphatic dicarboxylic acid unit (Aa) include linear or branched saturated aliphatic dicarboxylic acids having 3 to 20 carbon atoms.
Examples of linear saturated aliphatic dicarboxylic acids having 3 to 20 carbon atoms include, but are not limited to, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, dodecanedioic acid, tetradecanedioic acid, hexadecanedioic acid, octadecanedioic acid, eicosane dioic acid, and diglycolic acid.
Examples of branched saturated aliphatic dicarboxylic acids having 3 to 20 carbon atoms include, but are not limited to, dimethylmalonic acid, 2,2-dimethylsuccinic acid, 2,3-dimethylglutaric acid, 2,2-diethylsuccinic acid, 2,3-diethylglutaric acid, 2,2-dimethylglutaric acid, 2-methyladipic acid, and trimethyladipic acid.
The aliphatic dicarboxylic acids constituting the (Aa) aliphatic dicarboxylic acid unit may be used alone or in combination of two or more.
Among these, as the aliphatic dicarboxylic acid constituting the aliphatic dicarboxylic acid unit (A-a), a linear saturated aliphatic dicarboxylic acid having 6 or more carbon atoms is preferred since the polyamide composition tends to have better heat resistance, fluidity, toughness, low water absorbency, rigidity, and the like.

Specific examples of preferred linear saturated aliphatic dicarboxylic acids having 6 or more carbon atoms include adipic acid, sebacic acid, dodecanedioic acid, tetradecanedioic acid, hexadecanedioic acid, octadecanedioic acid, and eicosane dioic acid.
Among these, from the viewpoint of the heat resistance of the polyamide composition, adipic acid, sebacic acid, or dodecanedioic acid is preferred as the linear saturated aliphatic dicarboxylic acid having 6 or more carbon atoms.

Furthermore, the (A) aliphatic polyamide may further contain units derived from a polyvalent carboxylic acid having three or more valences, if necessary, within a range that does not impair the effects of the polyamide composition of this embodiment. Examples of the polyvalent carboxylic acid having three or more valences include trimellitic acid, trimesic acid, and pyromellitic acid. These polyvalent carboxylic acids having three or more valences may be used alone or in combination of two or more kinds.

((A-b) Aliphatic Diamine Unit)
Examples of the aliphatic diamine constituting the aliphatic diamine unit (A-b) include linear saturated aliphatic diamines having 2 to 20 carbon atoms, and branched saturated aliphatic diamines having 3 to 20 carbon atoms.
Examples of linear saturated aliphatic diamines having 2 to 20 carbon atoms include, but are not limited to, ethylenediamine, propylenediamine, tetramethylenediamine, pentamethylenediamine, hexamethylenediamine, heptamethylenediamine, octamethylenediamine, nonamethylenediamine, decamethylenediamine, undecamethylenediamine, dodecamethylenediamine, tridecamethylenediamine, and the like.
Examples of branched saturated aliphatic diamines having 3 to 20 carbon atoms include, but are not limited to, 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), 2,4-dimethyloctamethylenediamine, and the like.
The aliphatic diamine constituting the aliphatic diamine unit (Ab) may be used alone or in combination of two or more kinds.
Among these, the carbon number of the aliphatic diamine constituting the aliphatic diamine unit (A-b) is preferably 6 to 12, more preferably 6 to 10. When the carbon number of the aliphatic diamine constituting the aliphatic diamine unit (A-b) is equal to or more than the above lower limit, the heat resistance of the obtained molded article is more excellent. On the other hand, when the carbon number is equal to or less than the above upper limit, the crystallinity and releasability of the obtained molded article are more excellent.

Specific examples of preferred linear or branched saturated aliphatic diamines having 6 to 12 carbon atoms include hexamethylenediamine, 2-methylpentamethylenediamine, and 2-methyl-1,8-octanediamine.
Among these, hexamethylenediamine or 2-methylpentamethylenediamine is preferred as the linear or branched saturated aliphatic diamine having from 6 to 12 carbon atoms. By containing such an aliphatic diamine unit (A-b), the heat resistance, rigidity, etc. of a molded article obtained from the polyamide composition are more excellent.

The aliphatic polyamide (A) may further contain units derived from trivalent or higher polyvalent aliphatic amines, if necessary, within the scope of not impairing the effects of the polyamide composition of this embodiment. Examples of trivalent or higher polyvalent aliphatic amines include bishexamethylenetriamine.

((A-c) At least one structural unit selected from the group consisting of lactam units and aminocarboxylic acid units)
The aliphatic polyamide (A) may contain at least one structural unit (Ac) selected from the group consisting of lactam units and aminocarboxylic acid units. By containing such units, a polyamide having excellent toughness tends to be obtained.
The terms "lactam unit" and "aminocarboxylic acid unit" used herein refer to poly(condensed) lactam and aminocarboxylic acid.

Examples of lactams constituting the lactam unit include, but are not limited to, butyrolactam, pivalolactam, ε-caprolactam, caprylolactam, enantholactam, undecanolactam, laurolactam (dodecanolactam), and the like.
Among them, the lactam constituting the lactam unit is preferably ε-caprolactam or laurolactam, and more preferably ε-caprolactam. By including such a lactam, the toughness of a molded article obtained from the polyamide composition tends to be superior.

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.
The amino carboxylic acid constituting the amino carboxylic acid unit is preferably a linear or branched saturated aliphatic carboxylic acid having from 4 to 14 carbon atoms and substituted with an amino group at the ω position. Examples of such amino carboxylic acids include, but are not limited to, 6-aminocaproic acid, 11-aminoundecanoic acid, and 12-aminododecanoic acid. Other examples of amino carboxylic acids include para-aminomethylbenzoic acid.

The lactam and aminocarboxylic acid constituting at least one structural unit selected from the group consisting of (A-c) lactam units and aminocarboxylic acid units may each be used alone or in combination of two or more types.

Among these, as the aliphatic polyamide (A), from the viewpoints of mechanical properties, heat resistance, moldability, and toughness, polyamides containing dicarboxylic acid units and diamine units are preferred, and polyamide 66 (PA66) is more preferred. PA66 is considered to be a suitable material for automotive parts because of its excellent mechanical properties, heat resistance, moldability, and toughness.

The content of (A) aliphatic polyamide can be, for example, 10% by mass or more and 90% by mass or less, for example, 50% by mass or more and 80% by mass or less, for example, 55% by mass or more and 70% by mass or less, based on the total mass of polyamide in the polyamide composition.

((A) Weight average molecular weight Mw(A) of aliphatic polyamide)
As an index of the molecular weight of the aliphatic polyamide (A), the weight average molecular weight Mw(A) can be used. The weight average molecular weight Mw(A) of the aliphatic polyamide is preferably 10,000 to 50,000, more preferably 17,000 to 45,000, even more preferably 20,000 to 45,000, even more preferably 25,000 to 45,000, particularly preferably 30,000 to 45,000, and most preferably 35,000 to 40,000.
When the weight average molecular weight Mw(A) is within the above range, a polyamide composition having excellent mechanical properties, in particular, water absorption rigidity, hot rigidity, and fluidity, as well as tensile strength, flexural modulus when water absorbed, long-term heat resistance, tracking resistance, and the like when formed into a molded product can be obtained.
The weight average molecular weight Mw(A) can be measured by using GPC as described in the following Examples.

[(B) Semi-aromatic polyamide]
(B) The semi-aromatic polyamide is a polyamide containing diamine units and dicarboxylic acid units.
The semi-aromatic polyamide (B) preferably contains 20 mol % or more and 80 mol % or less of aromatic constituent units, more preferably 30 mol % or more and 70 mol % or less of aromatic constituent units, and even more preferably 40 mol % or more and 60 mol % or less of aromatic constituent units, based on the total constituent units of the semi-aromatic polyamide (B). The term "aromatic constituent units" used herein means aromatic diamine units and aromatic dicarboxylic acid units.

In addition, the semi-aromatic polyamide (B) is preferably a polyamide containing dicarboxylic acid units (Ba-a) containing 50 mol % or more of isophthalic acid units relative to the total dicarboxylic acid units of the semi-aromatic polyamide (B), and diamine units (B-b) containing diamine units having 4 to 10 carbon atoms.
In this case, the total content of isophthalic acid units and diamine units having 4 to 10 carbon atoms in the semi-aromatic polyamide (B) is preferably 50 mol% or more, more preferably 80 mol% or more and 100 mol% or less, even more preferably 90 mol% or more and 100 mol% or less, and particularly preferably 100 mol%, based on the total constituent units of the semi-aromatic polyamide (B).

The proportion of the specified monomer units constituting (B) the semi-aromatic polyamide can be measured by nuclear magnetic resonance spectroscopy (NMR) or the like.

((Ba) Dicarboxylic acid unit)
The dicarboxylic acid unit (Ba) is not particularly limited, and examples thereof include an aromatic dicarboxylic acid unit, an aliphatic dicarboxylic acid unit, and an alicyclic dicarboxylic acid unit.
Among these, the dicarboxylic acid unit (Ba-a) preferably contains isophthalic acid in an amount of 50 mol% or more, more preferably 65 mol% or more and 100 mol% or less, even more preferably 75 mol% or more and 100 mol% or less, particularly preferably 80 mol% or more and 100 mol% or less, and most preferably 100 mol%.
When the ratio of isophthalic acid units in the (Ba) dicarboxylic acid units is equal to or more than the above lower limit, a polyamide composition tends to be obtained that simultaneously satisfies mechanical properties, particularly rigidity when absorbing water, rigidity when hot, flowability, etc. Furthermore, molded articles obtained from the polyamide composition tend to be superior in tensile strength, flexural modulus when absorbing water, long-term heat resistance, and tracking resistance.

(1) Aromatic dicarboxylic acid unit Examples of aromatic dicarboxylic acids constituting aromatic dicarboxylic acid units other than isophthalic acid units include, but are not limited to, dicarboxylic acids having an aromatic group such as a phenyl group, a naphthyl group, etc. The aromatic group of the aromatic dicarboxylic acid may be unsubstituted or may have a substituent.

The substituent is not particularly limited, but examples thereof include an alkyl group having from 1 to 4 carbon atoms, an aryl group having from 6 to 10 carbon atoms, an arylalkyl group having from 7 to 10 carbon atoms, an alkylaryl group having from 7 to 10 carbon atoms, a halogen group, a silyl group having from 1 to 6 carbon atoms, a sulfonic acid group, and a salt thereof (such as a sodium salt).
Examples of the alkyl group having 1 to 4 carbon atoms include, but are not limited to, a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, and a tert-butyl group.
Examples of the aryl group having 6 to 10 carbon atoms include, but are not limited to, a phenyl group, a naphthyl group, and the like.
Examples of the arylalkyl group having 7 to 10 carbon atoms include, but are not limited to, a benzyl group.
Examples of the alkylaryl group having 7 to 10 carbon atoms include, but are not limited to, a tolyl group, a xylyl group, and the like.
Examples of the halogen group include, but are not limited to, a fluoro group, a chloro group, a bromo group, and an iodo group.
Examples of the silyl group having 1 to 6 carbon atoms include, but are not limited to, a trimethylsilyl group, a tert-butyldimethylsilyl group, and the like.
Among these, the aromatic dicarboxylic acid constituting the aromatic dicarboxylic acid unit other than the isophthalic acid unit is preferably an aromatic dicarboxylic acid having 8 to 20 carbon atoms which is unsubstituted or substituted with a specific substituent.

Specific examples of unsubstituted or predetermined substituent-substituted aromatic dicarboxylic acids having 8 to 20 carbon atoms include, but are not limited to, terephthalic acid, naphthalenedicarboxylic acid, 2-chloroterephthalic acid, 2-methylterephthalic acid, 5-methylisophthalic acid, and 5-sodium sulfoisophthalic acid.
The aromatic dicarboxylic acid constituting the aromatic dicarboxylic acid unit may be used alone or in combination of two or more kinds.

(2) Aliphatic Dicarboxylic Acid Unit Examples of the aliphatic dicarboxylic acid constituting the aliphatic dicarboxylic acid unit include linear or branched saturated aliphatic dicarboxylic acids having 3 to 20 carbon atoms.

Examples of linear saturated aliphatic dicarboxylic acids having 3 to 20 carbon atoms include, but are not limited to, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, dodecanedioic acid, tetradecanedioic acid, hexadecanedioic acid, octadecanedioic acid, eicosane dioic acid, and diglycolic acid.
Examples of branched saturated aliphatic dicarboxylic acids having 3 to 20 carbon atoms include, but are not limited to, dimethylmalonic acid, 2,2-dimethylsuccinic acid, 2,3-dimethylglutaric acid, 2,2-diethylsuccinic acid, 2,3-diethylglutaric acid, 2,2-dimethylglutaric acid, 2-methyladipic acid, and trimethyladipic acid.

(3) Alicyclic dicarboxylic acid unit The alicyclic dicarboxylic acid constituting the alicyclic dicarboxylic acid unit (hereinafter sometimes referred to as "alicyclic dicarboxylic acid unit") is, but is not limited to, for example, an alicyclic dicarboxylic acid having an alicyclic structure with 3 to 10 carbon atoms. Among them, the alicyclic dicarboxylic acid is preferably an alicyclic dicarboxylic acid having an alicyclic structure with 5 to 10 carbon atoms.

Examples of such alicyclic dicarboxylic acids include, but are not limited to, 1,4-cyclohexanedicarboxylic acid, 1,3-cyclohexanedicarboxylic acid, 1,3-cyclopentanedicarboxylic acid, etc. Among them, 1,4-cyclohexanedicarboxylic acid is preferred as the alicyclic dicarboxylic acid.
The alicyclic dicarboxylic acid constituting the alicyclic dicarboxylic acid unit may be used alone or in combination of two or more kinds.

The alicyclic group of the alicyclic dicarboxylic acid may be unsubstituted or may have a substituent. Examples of the substituent include an alkyl group having 1 to 4 carbon atoms. Examples of the alkyl group having 1 to 4 carbon atoms include the same ones exemplified in the above "aromatic dicarboxylic acid unit."

The dicarboxylic acid units other than the isophthalic acid units preferably contain aromatic dicarboxylic acid units, and more preferably contain aromatic dicarboxylic acids having 6 or more carbon atoms.
By using such a dicarboxylic acid, a polyamide composition tends to be obtained that simultaneously satisfies mechanical properties, particularly water-absorbed rigidity, hot rigidity, fluidity, etc. Furthermore, molded articles obtained from the polyamide composition tend to be superior in tensile strength, flexural modulus when absorbing water, long-term heat resistance, and tracking resistance.

In the (B) semi-aromatic polyamide, the dicarboxylic acid constituting the (Ba) dicarboxylic acid unit is not limited to the compounds described above as the dicarboxylic acid, and may be a compound equivalent to the above dicarboxylic acid.
The term "compound equivalent to a dicarboxylic acid" used herein means a compound that can have a dicarboxylic acid structure similar to the dicarboxylic acid structure derived from the above dicarboxylic acid. Examples of such compounds include, but are not limited to, anhydrides of dicarboxylic acids and halides of dicarboxylic acids.

Furthermore, the (B) semi-aromatic polyamide may further contain units derived from a trivalent or higher polyvalent carboxylic acid, if necessary, within a range that does not impair the effects of the polyamide composition of the present embodiment.
Examples of the trivalent or higher polyvalent carboxylic acid include trimellitic acid, trimesic acid, pyromellitic acid, etc. These trivalent or higher polyvalent carboxylic acids may be used alone or in combination of two or more.

((B-b) Diamine Unit)
The diamine unit (B-b) constituting the semi-aromatic polyamide (B) is not particularly limited, and examples thereof include an aromatic diamine unit, an aliphatic diamine unit, an alicyclic diamine unit, etc. Among them, the diamine unit (B-b) constituting the semi-aromatic polyamide (B) preferably contains a diamine unit having 4 to 10 carbon atoms, and more preferably contains a diamine unit having 6 to 10 carbon atoms.

(1) Aliphatic Diamine Unit Examples of the aliphatic diamine constituting the aliphatic diamine unit include linear saturated aliphatic diamines having 4 to 20 carbon atoms.
Examples of linear saturated aliphatic diamines having 4 to 20 carbon atoms include, but are not limited to, ethylenediamine, propylenediamine, tetramethylenediamine, pentamethylenediamine, hexamethylenediamine, heptamethylenediamine, octamethylenediamine, nonamethylenediamine, decamethylenediamine, undecamethylenediamine, dodecamethylenediamine, tridecamethylenediamine, and the like.

(2) 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.

(3) 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. Specific examples of aromatic diamines include metaxylylenediamine.

The diamines constituting the diamine units may be used alone or in combination of two or more.
Among these, as the diamine unit (B-b), an aliphatic diamine unit is preferable, a linear saturated aliphatic diamine unit having from 4 to 10 carbon atoms is more preferable, a linear saturated aliphatic diamine unit having from 6 to 10 carbon atoms is even more preferable, and a hexamethylenediamine unit is particularly preferable.
By using such a diamine, a polyamide composition tends to be obtained that simultaneously satisfies mechanical properties, particularly rigidity when absorbing water, rigidity when hot, flowability, etc. Furthermore, molded articles obtained from the polyamide composition tend to be superior in tensile strength, flexural modulus when absorbing water, long-term heat resistance, and tracking resistance.

(B) As the semi-aromatic polyamide, polyamide 6I (polyhexamethylene isophthalamide), polyamide 9I, or polyamide 10I is preferred, with polyamide 6I being more preferred. Polyamide 6I is considered to be a suitable material for automotive parts because of its excellent heat resistance, moldability, and flame retardancy.

The content of the (B) semi-aromatic polyamide can be, for example, 10 mass% or more and 90 mass% or less, for example, 20 mass% or more and 50 mass% or less, for example, 30 mass% or more and 45 mass% or less, relative to the total mass of polyamide in the polyamide composition.
By setting the content of the semi-aromatic polyamide (B) within the above range, the mechanical properties of the molded article obtained from the polyamide composition are more excellent. In addition, by including a component such as a filler, the tensile strength, flexural modulus when absorbing water, long-term heat resistance, and tracking resistance of the molded article obtained from the polyamide composition tend to be more excellent.

((B) Weight average molecular weight Mw(B) of semi-aromatic polyamide)
As an index of the molecular weight of the semi-aromatic polyamide (B), the weight average molecular weight Mw(B) can be used. The weight average molecular weight Mw(B) of the semi-aromatic polyamide is preferably 10,000 to 50,000, more preferably 15,000 to 45,000, even more preferably 15,000 to 40,000, even more preferably 17,000 to 35,000, particularly preferably 17,000 to 33,000, and most preferably 18,000 to 30,000.
When the weight average molecular weight Mw(B) is within the above range, a polyamide composition having excellent mechanical properties, in particular, water absorption rigidity, hot rigidity, and fluidity, as well as tensile strength, flexural modulus when water absorbed, long-term heat resistance, tracking resistance, and the like when formed into a molded product can be obtained.
The weight average molecular weight Mw(B) can be measured by using GPC as described in the following Examples.

[End-capping agent]
The terminals of the polyamides ((A) the aliphatic polyamide and (B) the semi-aromatic polyamide) contained in the polyamide composition of the present embodiment may be capped with a known terminal capping agent.
Such an end-capping agent can also be added as a molecular weight regulator when producing a polyamide from the above dicarboxylic acid and the above diamine, or from at least one member selected from the group consisting of the above lactam and the above aminocarboxylic acid.

Examples of the end-capping agent include, but are not limited to, monocarboxylic acids, monoamines, acid anhydrides (e.g., phthalic anhydride), monoisocyanates, monoesters, monoalcohols, etc. Only one type of end-capping agent may be used alone, or two or more types may be used in combination.
Among them, the terminal blocking agent is preferably a monocarboxylic acid or a monoamine. By blocking the terminals of the polyamide with the terminal blocking agent, the thermal stability of a molded article obtained from the polyamide composition tends to be superior.

The monocarboxylic acid that can be used as the end-capping agent may be any one that is reactive with amino groups that may be present at the terminals of the polyamide. Examples of the monocarboxylic acid include, but are not limited to, aliphatic monocarboxylic acids, alicyclic monocarboxylic acids, and aromatic monocarboxylic acids.
Examples of the aliphatic monocarboxylic acid include 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.
An example of the alicyclic monocarboxylic acid is cyclohexanecarboxylic acid.
Examples of aromatic monocarboxylic acids include 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.
In particular, from the viewpoints of fluidity and mechanical strength, it is preferable that the terminals of the semi-aromatic polyamide (B) are blocked with acetic acid.

The monoamine usable as the end-capping agent may be any monoamine that is reactive with a carboxy group that may be present at the end of the polyamide, and may include, but is not limited to, aliphatic monoamines, alicyclic monoamines, aromatic monoamines, etc.
Examples of the aliphatic monoamine include methylamine, ethylamine, propylamine, butylamine, hexylamine, octylamine, decylamine, stearylamine, dimethylamine, diethylamine, dipropylamine, and dibutylamine.
Examples of the alicyclic monoamine include cyclohexylamine and dicyclohexylamine.
Examples of aromatic monoamines include aniline, toluidine, diphenylamine, and naphthylamine.
These monoamines may be used alone or in combination of two or more.

Polyamide compositions containing polyamides end-capped with an end-capping agent tend to have superior heat resistance, flowability, toughness, low water absorption, and rigidity.

[Method of producing polyamides ((A) aliphatic polyamides and (B) semi-aromatic polyamides)]
When producing the polyamides ((A) aliphatic polyamide and (B) semi-aromatic polyamide) contained in the polyamide composition of this embodiment, 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 in the molar ratio, the molar amount of the total diamines relative to the total molar amount of dicarboxylic acids is preferably 0.9 to 1.2, more preferably 0.95 to 1.1, and even more preferably 0.98 to 1.05.

The method for producing polyamide includes, but is not limited to, the following polymerization step (1) or (2).
(1) A step of polymerizing a combination of a dicarboxylic acid constituting a dicarboxylic acid unit and a diamine constituting a diamine unit to obtain a polymer.
(2) A step of polymerizing one or more members selected from the group consisting of lactams constituting the lactam units and aminocarboxylic acids constituting the aminocarboxylic acid units to obtain a polymer.

The method for producing polyamide preferably further includes, after the polymerization step, an increase step for increasing the degree of polymerization of the polyamide. If necessary, the method may include, after the polymerization step and the increase step, a sealing step for sealing the ends of the obtained polymer with a terminal sealing agent.

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

Among them, a specific method for producing polyamide is preferably a production method including a hot melt polymerization method. In addition, when producing polyamide by hot melt polymerization, 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 controlled to 14 kg/cm ² or more and 25 kg/cm ² or less (gauge pressure), and heating is continued. Next, the pressure in the tank is reduced over 30 minutes or more until it becomes atmospheric pressure (gauge pressure is 0 kg/cm ² ).

In the method for producing a polyamide, the polymerization form is not particularly limited, and may be a batch type or a continuous type.
The polymerization apparatus used for producing polyamide 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 (such as a kneader).

Hereinafter, as a method for producing polyamide, a method for producing polyamide by a batch-type hot melt polymerization method will be specifically described, but the method for producing polyamide is not limited thereto.
First, an aqueous solution containing about 40% by mass to about 60% by mass of raw material components for polyamide (a combination of dicarboxylic acid and diamine, and, if necessary, at least one selected from the group consisting of lactam and aminocarboxylic acid) is prepared.The aqueous solution is then 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.

The resulting concentrated solution is then transferred to an autoclave and heated until the pressure in the autoclave is between about 1.2 MPa and 2.2 MPa (gauge pressure).

Next, in the autoclave, the pressure is maintained at about 1.2 MPa to 2.2 MPa (gauge pressure) while removing at least one of the water and gas components. Next, when the temperature reaches about 220°C to 260°C, the pressure is reduced to atmospheric pressure (gauge pressure: 0 MPa). After the pressure inside the autoclave is reduced to atmospheric pressure, the pressure can be reduced as necessary to effectively remove the by-product water.

The autoclave is then pressurized with an inert gas such as nitrogen, and the polyamide melt is extruded from the autoclave as strands. The extruded strands are cooled and cut to obtain polyamide pellets.

[Polyamide polymer end]
The polymer terminals of the polyamides ((A) aliphatic polyamide and (B) semi-aromatic polyamide) contained in the polyamide composition of the present embodiment are not particularly limited, but can be classified and defined as follows: 1) to 4).
That is, 1) the amino terminus, 2) the carboxy terminus, 3) the terminus provided by a capping agent, and 4) the other terminus.
1) The amino terminus is a polymer end having an amino group ( _-NH2 group) and is derived from a diamine unit.
2) The carboxy terminal is a polymer end having a carboxy group (—COOH group) and is derived from a dicarboxylic acid.
3) The term "terminals formed by a capping agent" refers to terminals formed when a capping agent is added during polymerization. Examples of the capping agent include the above-mentioned terminal capping agents.
4) "Other terminals" are polymer terminals that are not classified into the above-mentioned 1) to 3). Specific examples of other terminals include terminals generated by deammonia reaction of amino terminals, terminals generated by decarboxylation of carboxy terminals, etc.

[(C) Flame retardant]
The (C) flame retardant is not particularly limited as long as it is a flame retardant containing a halogen element or phosphorus, and examples thereof include bromine-based flame retardants, phosphorus-based flame retardants, etc. Among them, phosphorus-based flame retardants are preferred as the (C) flame retardant from the viewpoints of not impairing the dispersibility of the (E) polyhydric alcohol and being superior in long-term heat resistance and creep characteristics when the polyamide composition is molded into a molded article.

(Brominated flame retardants)
Examples of bromine-based flame retardants include hexabromocyclododecane (HBCD), decabromodiphenyl oxide (DBDPO), octabromodiphenyl oxide, tetrabromobisphenol A (TBBA), bis(tribromophenoxy)ethane, bis(pentabromophenoxy)ethane (BPBPE), tetrabromobisphenol A epoxy resin (TBBA epoxy), tetrabromobisphenol A carbonate (TBBA-PC), ethylene(bistetrabromophthalic)imide (EBTBPI), ethylenebispentabromodiphenyl, tris(tribromophenoxy)triazine (TTBPTA), bis(dibromopropyl)tetrabromobisphenol A (DBP-TB BA), bis(dibromopropyl)tetrabromobisphenol S (DBP-TBBS), brominated polyphenylene ether (including poly(di)bromophenylene ether, etc.) (BrPPE), brominated polystyrene (including polydibromostyrene, polytribromostyrene, crosslinked brominated polystyrene, etc.) (BrPS), brominated crosslinked aromatic polymers, brominated epoxy resins, brominated phenoxy resins, brominated styrene-maleic anhydride polymers, tetrabromobisphenol S (TBBS), tris(tribromoneopentyl)phosphate (TTBNPP), polybromotrimethylphenylindane (PBPI), tris(dibromopropyl)-isocyanurate (TDBPIC), and the like.

(Phosphorus-based flame retardant)
The phosphorus-based flame retardant is not particularly limited as long as it does not contain a halogen element and contains a phosphorus element. Examples of the phosphorus-based flame retardant include a phosphate ester-based flame retardant, a melamine polyphosphate-based flame retardant, a phosphazene-based flame retardant, a phosphinic acid-based flame retardant, and a red phosphorus-based flame retardant.
Among them, the phosphorus-based flame retardant is preferably a phosphate-based flame retardant, a melamine polyphosphate-based flame retardant, a phosphazene-based flame retardant or a phosphinic acid-based flame retardant, and more preferably a phosphinic acid-based flame retardant.

Specific examples of the phosphinic acid flame retardant include at least one phosphinic acid salt selected from the group consisting of a phosphinic acid salt represented by the following general formula (1) (hereinafter, sometimes abbreviated as "phosphinic acid salt (1)"), a diphosphinic acid salt represented by the following general formula (2) (hereinafter, sometimes abbreviated as "diphosphinic acid salt (2)"), and condensates thereof.

(In general formula (1), R ¹¹ and R ¹² each independently represent an alkyl group having 1 to 6 carbon atoms or an aryl group having 6 to 10 carbon atoms. M ⁿ¹¹⁺ represents a metal ion having a valence of n11. M represents an element belonging to Group 2 or Group 15 of the periodic table or a transition element. n11 is 2 or 3. When n11 is 2 or 3, a plurality of R ¹¹ and R ¹² may be the same or different.
In the general formula (2), R ²¹ and R ²² are each independently an alkyl group having 1 to 6 carbon atoms or an aryl group having 6 to 10 carbon atoms. Y ²¹ is an alkylene group having 1 to 10 carbon atoms or an arylene group having 6 to 10 carbon atoms. M' ^m21+ is a metal ion having a valence of m21. M' is an element or a transition element belonging to Group 2 or Group 15 of the periodic table. n21 is an integer of 1 to 3. When n21 is 2 or 3, the multiple R ²¹ , R ²² and Y ²¹ may be the same or different. m21 is 2 or 3. x is 1 or 2. When x is 2, the multiple M' may be the same or different. n21, x and m21 are integers that satisfy the relationship formula 2×n21=m21×x.)

(1) R ¹¹ , R ¹² , R ²¹ and R ²²
R ¹¹ , R ¹² , R ²¹ and R ²² are each independently an alkyl group having 1 to 6 carbon atoms, or an aryl group having 6 to 10 carbon atoms. When n11 is 2 or 3, the multiple R ¹¹ and R ¹² may be the same or different, but are preferably the same because of ease of production. When n21 is 2 or 3, the multiple R ²¹ and R ²² may be the same or different, but are preferably the same because of ease of production.

The alkyl group may be either chain-like or cyclic, but is preferably chain-like. The chain-like alkyl group may be either linear or branched. Examples of linear alkyl groups include methyl, ethyl, n-propyl, n-butyl, n-pentyl, and n-hexyl groups. Examples of branched alkyl groups include 1-methylethyl, 1-methylpropyl, 2-methylpropyl, 1,1-dimethylethyl, 1-methylbutyl, 2-methylbutyl, 3-methylbutyl, 1,1-dimethylpropyl, 1,2-dimethylpropyl, 2,2-dimethylpropyl, 1-methylpentyl, 2-methylpentyl, 3-methylpentyl, 4-methylpentyl, 1,1-dimethylbutyl, 1,2-dimethylbutyl, 1,3-dimethylbutyl, 2,2-dimethylbutyl, 2,3-dimethylbutyl, 3,3-dimethylbutyl, 1-ethylbutyl, 2-ethylbutyl, and 1,1,2-trimethylpropyl groups.

Examples of aryl groups include phenyl and naphthyl groups.

The alkyl 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.
Specific examples of the alkyl group having a substituent include a benzyl group.
Specific examples of the aryl group having a substituent include a tolyl group and a xylyl group.

Among these, R ¹¹ , R ¹² , R ²¹ and R ²² are preferably an alkyl group having 1 to 6 carbon atoms, and more preferably a methyl group or an ethyl group.

(2) ^Y21
Y21 is an alkylene group having 1 to 10 carbon atoms or an arylene group having 6 to 10 carbon atoms. When n21 is 2 or 3, a plurality of ^Y21 may be the same or different, but is preferably the same in terms of ease of production.

The alkylene group may be either chain-like or cyclic, but is preferably chain-like. The chain-like alkylene group may be either linear or branched. Examples of linear alkylene groups include methylene, ethylene, trimethylene, tetramethylene, pentamethylene, and hexamethylene groups. Examples of branched alkylene groups include 1-methylethylene and 1-methylpropylene groups.

Examples of arylene groups include phenylene groups and naphthylene groups.

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

Specific examples of alkylene groups having a substituent include a phenylmethylene group, a phenylethylene group, a phenyltrimethylene group, and a phenyltetramethylene group.

Specific examples of substituted arylene groups include methylphenylene groups, ethylphenylene groups, tert-butylphenylene groups, methylnaphthylene groups, ethylnaphthylene groups, and tert-butylnaphthylene groups.

Among these, Y ²¹ is preferably an alkylene group having 1 to 10 carbon atoms, and more preferably a methylene group or an ethylene group.

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

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

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

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

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

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

Methods for producing phosphinates are not particularly limited, but examples include the methods described in Patent Document 5, Patent Document 6, and Patent Document 7. Specifically, they are produced in an aqueous solution using phosphinic acid and a metal carbonate, metal hydroxide, or metal oxide. These are essentially monomeric compounds, but also include polymeric phosphinates, which are condensates with a degree of condensation of 1 to 3 depending on the reaction conditions and environment.

The content of the flame retardant (C) is preferably 0.1 mass% or more and 30 mass% or less, more preferably 5 mass% or more and 30 mass% or less, still more preferably 5 mass% or more and 28 mass% or less, and particularly preferably 8 mass% or more and 25 mass% or less, relative to the mass of the polyamide composition.
By setting the content of the flame retardant (C) to the above lower limit or more, a polyamide composition having superior flame retardancy can be obtained. On the other hand, by setting the content of the flame retardant (C) to the above upper limit or less, a polyamide composition having superior flame retardancy can be obtained without impairing the properties of the polyamide.

[(D) Polymer containing α,β-unsaturated dicarboxylic acid anhydride as a structural unit and/or styrene-acrylonitrile copolymer]
The polyamide composition of the present embodiment contains (D) a polymer containing an α,β-unsaturated dicarboxylic acid anhydride unit and/or a styrene-acrylonitrile copolymer, and thus can be a polyamide composition having more excellent mechanical properties such as toughness and rigidity.

((D1) Polymer containing α,β-unsaturated dicarboxylic acid anhydride as a structural unit)
Examples of the polymer containing an α,β-unsaturated dicarboxylic acid anhydride unit (D1) include a polymer containing an α,β-unsaturated dicarboxylic acid anhydride as a copolymerization component and a polymer modified with an α,β-unsaturated dicarboxylic acid anhydride.
Examples of the α,β-unsaturated dicarboxylic acid anhydride include a compound represented by the following general formula (3) (hereinafter, sometimes referred to as "compound (3)").

In the general formula (3), R ³¹ and R ³² are each independently a hydrogen atom or an alkyl group having 1 to 3 carbon atoms. R ³¹ and R ³² may be the same or different. In particular, it is preferable that R ³¹ and R ³² are the same from the viewpoint of ease of production.

Examples of the alkyl group having 1 to 3 carbon atoms in R ³¹ and R ³² include a methyl group, an ethyl group, a propyl group, and an isopropyl group.
Among these, R ³¹ and R ³² are preferably a hydrogen atom or a methyl group, and more preferably a hydrogen atom.

Preferred compound (3) (α,β-unsaturated dicarboxylic anhydride) includes, for example, maleic anhydride, methyl maleic anhydride, etc. Among them, maleic anhydride is preferred as compound (3) (α,β-unsaturated dicarboxylic anhydride).

As a polymer containing an α,β-unsaturated dicarboxylic anhydride as a copolymerization component, from the viewpoint of efficiency in improving flame retardancy (which is manifested even with a small amount added), a copolymer of an aromatic vinyl compound and an α,β-unsaturated dicarboxylic anhydride is preferred.

The aromatic vinyl compound used in the production of the copolymer of an aromatic vinyl compound and an α,β-unsaturated dicarboxylic acid anhydride is, for example, the compound represented by the following general formula (4) (hereinafter, sometimes referred to as "compound (4)").

In the general formula (4), R ⁴¹ is hydrogen or an alkyl group having 1 to 3 carbon atoms. R ⁴² is a substituent of a benzene ring. R ⁴² is an alkyl group having 1 to 3 carbon atoms. n41 is an integer of 0 to 5. When n41 is 0, the benzene ring is unsubstituted. When n41 is 2 or more, the multiple R ^42s may be the same or different.

Examples of the alkyl group having 1 to 3 carbon atoms in R ⁴¹ and R ⁴² include the same groups as those exemplified in the compound (3) above.
Among them, R ⁴¹ is preferably a hydrogen atom or a methyl group, and R ⁴² is preferably a methyl group.

n41 represents the number of R ⁴² which is a substituent of a benzene ring. n41 is preferably an integer of 0 or more and 1 or less, and more preferably 0.

Preferred compound (4) (aromatic vinyl compound) includes, for example, styrene, α-methylstyrene, p-methylstyrene, etc. Among them, styrene is preferred as compound (4) (aromatic vinyl compound).

(D1) When the polymer containing α,β-unsaturated dicarboxylic anhydride units contains aromatic vinyl compound units, the aromatic vinyl compound units have affinity with the flame retardant (C), and the α,β-unsaturated dicarboxylic anhydride units have affinity with or react with the semi-aromatic polyamide (B). This is thought to help disperse the flame retardant (C) in the polyamide matrix, allowing the flame retardant to be finely dispersed.

The proportion of aromatic vinyl compound units and α,β-unsaturated dicarboxylic anhydride units in the copolymer of an aromatic vinyl compound and an α,β-unsaturated dicarboxylic anhydride is preferably 50% by mass or more and 99% by mass or less, and 1% by mass or more and 50% by mass or less of the α,β-unsaturated dicarboxylic anhydride units in terms of flame retardancy, fluidity, thermal decomposition resistance, etc. of the resulting polyamide composition. The proportion of α,β-unsaturated dicarboxylic anhydride units in the copolymer of an aromatic vinyl compound and an α,β-unsaturated dicarboxylic anhydride is more preferably 5% by mass or more and 20% by mass or less, and even more preferably 8% by mass or more and 15% by mass or less.
By making the proportion of α,β-unsaturated dicarboxylic anhydride units in the copolymer of an aromatic vinyl compound and an α,β-unsaturated dicarboxylic anhydride equal to or greater than the lower limit, a polyamide composition having excellent mechanical properties such as toughness and rigidity, as well as excellent flame retardancy can be obtained. On the other hand, by making the proportion of α,β-unsaturated dicarboxylic anhydride units equal to or less than the upper limit, deterioration of the polyamide composition caused by the α,β-unsaturated dicarboxylic anhydride can be more effectively prevented.

Examples of polymers modified with α,β-unsaturated dicarboxylic anhydrides include polyphenylene ether and polypropylene modified with α,β-unsaturated dicarboxylic anhydrides. Among these, maleic anhydride-modified polyphenylene ether is preferred as a polymer modified with α,β-unsaturated dicarboxylic anhydrides.

The content of the polymer (D1) containing an α,β-unsaturated dicarboxylic acid anhydride as a structural unit is from 0.1 mass% to 8.0 mass%, preferably from 1.0 mass% to 8.0 mass%, more preferably from 2.0 mass% to 7.0 mass%, and even more preferably from 2.5 mass% to 6.5 mass%, relative to the mass of the polyamide composition.
By controlling the content of the polymer (D1) containing an α,β-unsaturated dicarboxylic anhydride as a structural unit to be equal to or greater than the above lower limit, a polyamide composition having better flame retardancy can be obtained. On the other hand, by controlling the content of the polymer (D1) containing an α,β-unsaturated dicarboxylic anhydride as a structural unit to be equal to or less than the above upper limit, a polyamide composition having better creep properties can be obtained.
Furthermore, by adjusting the content of the polymer (D1) containing an α,β-unsaturated dicarboxylic acid anhydride as a structural unit within the above range, it is possible to obtain a polyamide composition having superior long-term heat resistance and creep characteristics.

As an index of the molecular weight of the polymer (D1) containing an α,β-unsaturated dicarboxylic anhydride as a structural unit, the weight average molecular weight Mw(D1) can be used. The weight average molecular weight Mw(D1) of the polymer (D1) is preferably 10,000 to 70,000, more preferably 15,000 to 60,000, even more preferably 20,000 to 60,000, even more preferably 25,000 to 60,000, particularly preferably 25,000 to 55,000, and most preferably 30,000 to 55,000.
When the weight average molecular weight Mw(D1) is within the above range, a polyamide composition having excellent mechanical properties, in particular, water absorption rigidity, hot rigidity, and fluidity, as well as tensile strength, flexural modulus when water absorbed, long-term heat resistance, creep characteristics, and the like when formed into a molded article can be obtained.
The weight average molecular weight Mw(D1) can be measured by using GPC as described in the following Examples.

((D2) Styrene-acrylonitrile copolymer)
The (D2) styrene-acrylonitrile copolymer means a copolymer containing styrene units and acrylonitrile units as constituent components, and may be a copolymer consisting of styrene units and acrylonitrile units (AS resin) or a rubber-reinforced styrene-acrylonitrile copolymer (ABS resin).

From the viewpoints of heat resistance, fluidity, and moldability, the content of styrene units in (D2) styrene-acrylonitrile copolymer is preferably 10% by mass or more and 70% by mass or less, more preferably 50% by mass or more and 70% by mass or less, and even more preferably 60% by mass or more and 67% by mass or less, based on the total mass of the constituent units of (D2) styrene-acrylonitrile copolymer. Furthermore, the copolymer may be one in which a part of the styrene in the styrene-based polymer is replaced with a monomer such as α-methylstyrene, p-methylstyrene, vinylxylene, monochlorostyrene, dichlorostyrene, monobromostyrene, dibromostyrene, p-tert-butylstyrene, ethylstyrene, or vinylnaphthalene.

The content of acrylonitrile units in (D2) styrene-acrylonitrile copolymer is preferably 30% by mass or more, and more preferably 33% by mass or more, based on the total mass of the constituent units of (D2) styrene-acrylonitrile copolymer, since this provides better flame retardancy and long-term heat resistance. The upper limit of the content of acrylonitrile units is not particularly limited, but may be, for example, 90% by mass or less, 50% by mass or less, or 40% by mass or less.

By adding (D2) styrene-acrylonitrile copolymer to the polyamide composition of this embodiment, the flowability is improved and the dispersion of the flame retardant is improved, so that a strong and dense char (a carbonized layer formed by combustion) can be formed during combustion, and it is presumed that the flame retardancy is improved. Furthermore, when a heat stabilizer described below is added, the flowability is improved by adding (D2) styrene-acrylonitrile copolymer, and the dispersion of the heat stabilizer is improved, so it is presumed that the radical trapping efficiency of the heat stabilizer is increased and long-term heat resistance is improved.

The content of the styrene-acrylonitrile copolymer (D2) is preferably 0.1 mass% or more and 8.0 mass% or less, more preferably 0.5 mass% or more and 5.0 mass% or less, still more preferably 1.0 mass% or more and 4.0 mass% or less, and particularly preferably 1.0 mass% or more and 3.0 mass% or less, relative to the mass of the polyamide composition.
By setting the content of the styrene-acrylonitrile copolymer (D2) in the above range, it is possible to obtain a polyamide composition which is excellent in flame retardancy and has good long-term heat resistance when formed into a molded product.

[(E) Polyhydric alcohol]
The polyhydric alcohol (E) contained in the polyamide composition of this embodiment preferably has a melting point in the range of 150°C to 280°C. By having a melting point of the lower limit or higher, scattering is less likely to occur during kneading and mixing into the polyamide, and the loss of flowability can be effectively suppressed. On the other hand, by having a melting point of the upper limit or lower, the temperature is below the normal molding temperature, and a better flow effect can be exhibited. The melting point here means the apex of the endothermic peak (melting point) when measured by differential scanning calorimetry (DSC) used to measure the melting point and solidification point of a polymer.

Preferred polyhydric alcohols include pentaerythritol, dipentaerythritol, tripentaerythritol, trimethylolethane, etc. These polyhydric alcohols may be used alone or in combination of two or more. Among them, the polyhydric alcohol is preferably pentaerythritol, dipentaerythritol, or tripentaerythritol.

The content of (E) polyhydric alcohol is preferably 0.1% by mass or more and less than 10% by mass, more preferably 0.5% by mass or more and less than 9% by mass, even more preferably 1.0% by mass or more and less than 8% by mass, and particularly preferably 2.0% by mass or more and less than 5% by mass, based on the mass of the polyamide composition. By having the content of (E) polyhydric alcohol in the above range, a polyamide composition having excellent flowability, tensile strength when molded into a molded product, long-term heat resistance, creep characteristics, etc. can be obtained.

<(F) Filler>
The polyamide composition of the present embodiment may further contain a filler (F) in addition to the above components (A) to (E). By containing the filler (F), the polyamide composition can have more excellent mechanical properties such as toughness and rigidity.

(F) The filler is not particularly limited, and examples thereof include glass fibers, carbon fibers, calcium silicate fibers, potassium titanate fibers, aluminum borate fibers, glass flakes, talc, kaolin, mica, hydrotalcite, zinc carbonate, calcium hydrogen phosphate, wollastonite, zeolite, boehmite, magnesium oxide, calcium silicate, sodium aluminosilicate, magnesium silicate, ketjen black, acetylene black, furnace black, carbon nanotubes, graphite, brass, copper, silver, aluminum, nickel, iron, calcium fluoride, montmorillonite, swellable fluoromica, and apatite.
These fillers (F) may be used alone or in combination of two or more.
Among these, the filler (F) is preferably glass fiber, carbon fiber, glass flake, talc, kaolin, mica, calcium hydrogen phosphate, wollastonite, carbon nanotube, graphite, calcium fluoride, montmorillonite, expandable fluoromica, or apatite from the viewpoint of rigidity, strength, etc. Furthermore, the filler (F) is more preferably glass fiber or carbon fiber, and further preferably glass fiber.

(F) When the filler is glass fiber or carbon fiber, the number average fiber diameter (d) is preferably 3 μm or more and 30 μm or less. The weight average fiber length (L) is preferably 100 μm or more and 750 μm or less. Furthermore, the aspect ratio ((L)/(d)) of the number average fiber diameter (d) to the weight average fiber length (L) is preferably 10 or more and 100 or less. By using glass fiber or carbon fiber having the above configuration, higher properties can be exhibited.
In addition, when the filler (F) is glass fiber, the number average fiber diameter (d) is more preferably 3 μm or more and 30 μm or less, the weight average fiber length (L) is more preferably 103 μm or more and 500 μm or less, and the aspect ratio ((L)/(d)) is more preferably 3 or more and 100 or less.

(F) The number average fiber diameter and weight average fiber length of the filler can be measured by the following method.
First, a molded product of the polyamide composition is dissolved in a solvent in which the polyamide is soluble, such as formic acid. Next, from the insoluble components obtained, for example, 100 or more fillers are arbitrarily selected. Next, the fillers can be observed with an optical microscope, a scanning electron microscope, or the like to determine the filler number.

The content of the (F) filler in the polyamide composition is preferably 1 mass % or more and 80 mass % or less, more preferably 10 mass % or more and 70 mass % or less, even more preferably 15 mass % or more and 60 mass % or less, particularly preferably 30 mass % or more and 60 mass % or less, and most preferably 40 mass % or more and 50 mass % or less, based on the total mass of the polyamide composition.
When the content of the (F) filler is equal to or more than the above lower limit, the mechanical properties such as strength and rigidity of the polyamide composition tend to be improved. On the other hand, when the content of the (F) filler is equal to or less than the above upper limit, the polyamide composition tends to have better moldability.
In particular, when the (F) filler is glass fiber and the content of the (F) filler is within the above range relative to the total mass of the polyamide composition, the mechanical properties such as strength and rigidity of the polyamide composition tend to be further improved.

<(G) Other Additives>
In addition to the above components (A) to (E), the polyamide composition of this embodiment may also contain (G) other additives commonly used in polyamides, provided that the effects of the polyamide composition of this embodiment are not impaired. Examples of (G) other additives include (G1) moldability improvers, (G2) deterioration inhibitors, (G3) nucleating agents, (G4) heat stabilizers, etc.
The content of (G) other additives in the polyamide composition of the present embodiment varies depending on the type and 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 of the present embodiment.

[(G1) Moldability improver]
The moldability improver (G1) 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 moldability improver is also used as a "lubricant".

(Higher fatty acids)
Examples of higher fatty acids include linear or branched, saturated or unsaturated aliphatic monocarboxylic acids having 8 to 40 carbon atoms.
Examples of the linear or branched, saturated or unsaturated aliphatic monocarboxylic acid 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 8 to 40 carbon atoms include isopalmitic acid and isostearic acid.
Examples of the linear unsaturated aliphatic monocarboxylic acid having from 8 to 40 carbon atoms include oleic acid and erucic acid.
Examples of the branched unsaturated aliphatic monocarboxylic acid having 8 to 40 carbon atoms include isooleic acid.
Among these, stearic acid or montanic acid is preferred as the higher fatty acid.

(Higher fatty acid metal salts)
The 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, Group 2 and Group 3 elements of the Periodic Table, zinc, aluminum, and the like.
Examples of Group 1 elements in the Periodic Table include sodium and potassium.
Examples of Group 2 elements in the Periodic Table include calcium and magnesium.
Examples of Group 3 elements in the periodic table include scandium and yttrium.
Among these, elements of Groups 1 and 2 of the Periodic Table of the Elements or aluminum are preferred, and sodium, potassium, calcium, magnesium or aluminum is more preferred.

Specific examples of higher fatty acid metal salts include calcium stearate, aluminum stearate, zinc stearate, magnesium stearate, calcium montanate, sodium montanate, calcium palmitate, and the like.
Among these, as the higher fatty acid metal salt, a metal salt of montanic acid or a metal salt of stearic acid is preferred.

(Higher fatty acid ester)
The higher fatty acid ester is an ester of a higher fatty acid and an alcohol.
As the higher fatty acid ester, an ester of an aliphatic carboxylic acid having 8 to 40 carbon atoms and an aliphatic alcohol having 8 to 40 carbon atoms is preferred.
Examples of the aliphatic alcohol having 8 to 40 carbon atoms include stearyl alcohol, behenyl alcohol, and lauryl alcohol.
Specific examples of higher fatty acid esters include stearyl stearate and behenyl behenate.

(Higher fatty acid amide)
Higher fatty acid amides are amide compounds of higher fatty acids.
Examples of higher fatty acid amides 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.
These higher fatty acids, higher fatty acid metal salts, higher fatty acid esters and higher fatty acid amides may each be used alone or in combination of two or more.

[(G2) Deterioration inhibitor]
The deterioration inhibitor (G2) contained in the polyamide composition of the present embodiment is used for the purposes of preventing thermal deterioration and discoloration when heated, and improving heat aging resistance.
The deterioration inhibitor (G2) is not particularly limited, but examples thereof include copper compounds, phenol-based stabilizers, phosphite-based stabilizers, hindered amine-based stabilizers, triazine-based stabilizers, benzotriazole-based stabilizers, benzophenone-based stabilizers, cyanoacrylate-based stabilizers, salicylate-based stabilizers, and sulfur-based stabilizers.
Examples of the copper compound include copper acetate and copper iodide.
Examples of the phenol-based stabilizer include hindered phenol compounds.
These deterioration inhibitors (G2) may be used alone or in combination of two or more.

[(G3) Nucleating Agent]
The (G3) nucleating agent means a substance that, when added, provides at least one of the following effects (1) to (3):
(1) The effect of increasing the crystallization peak temperature of the polyamide 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 making the spherulites in the resulting molded product finer and more uniform in size.

Examples of the nucleating agent (G3) include, but are not limited to, talc, boron nitride, mica, kaolin, silicon nitride, carbon black, potassium titanate, and molybdenum disulfide.
The nucleating agent (G3) may be used alone or in combination of two or more kinds.
Among these, the nucleating agent (G3) is preferably talc or boron nitride from the viewpoint of nucleating effect.

In addition, since the effect of the nucleating agent is high, the number average particle size of the nucleating agent (G3) is preferably 0.01 μm or more and 10 μm or less.
The number average particle size of the nucleating agent can be measured by 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 with an optical microscope, a scanning electron microscope, or the like and measuring the particle size.

The content of the nucleating agent in the polyamide composition of the present embodiment is preferably 0.001 parts by mass or more and 1 part by mass or less, more preferably 0.001 parts by mass or more and 0.5 parts by mass or less, and even more preferably 0.001 parts by mass or more and 0.09 parts by mass or less, relative to 100 parts by mass of polyamide ((A) aliphatic polyamide and (B) semi-aromatic polyamide).
By setting the content of the nucleating agent to be equal to or more than the above lower limit per 100 parts by mass of polyamide, 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 per 100 parts by mass of polyamide, a polyamide composition having superior toughness can be obtained.

[(G4) Heat stabilizer]
Examples of the heat stabilizer (G4) include, but are not limited to, phenol-based heat stabilizers, phosphorus-based heat stabilizers, amine-based heat stabilizers, and metal salts of elements in Groups 3, 4, and 11 to 14 of the Periodic Table of the Elements.

(Phenol-based heat stabilizer)
Examples of the phenol-based heat stabilizer 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.
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], onate], 3,9-bis{2-[3-(3-tert-butyl-4-hydroxy-5-methylphenyl)propynyloxy]-1,1-dimethylethyl}-2,4,8,10-tetraoxaspiro[5,5]undecane, 3,5-di-tert-butyl-4-hydroxybenzylphosphonate-diethyl ester, 1,3,5-trimethyl-2,4,6-tris(3,5-di-tert-butyl-4-hydroxybenzyl)benzene, 1,3,5-tris(4-tert-butyl-3-hydroxy-2,6-dimethylbenzyl)isocyanuric acid, and the like.
These hindered phenol compounds may be used alone or in combination of two or more.

When a phenol-based heat stabilizer is used, the content of the phenol-based heat stabilizer in the polyamide composition is preferably 0.01 mass % or more and 1 mass % or less, and more preferably 0.05 mass % or more and 1 mass % or less, relative to the total mass of the polyamide composition.
When the content of the phenol-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.

(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(nonylphenyl)phosphite, tris(2,4-di-tert-butylphenyl)phosphite, and 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'-isopropylidene diphenyl diphosphite, 4,4'-isopropylidene bis(2-tert-butylphenyl)-di(nonylphenyl)phosphite, tris(biphenyl)phosphite, tetra(tridecyl)-1,1,3-tris(2-methyl-5-tert-butyl-4-hydroxyphenyl)butane diphosphite, tetra(tridecyl)-4,4'-butylidene bis(3-methyl-6-tert-butylphenyl)diphosphite, tetra(C12-C15 mixed alkyl)-4,4'-isopropylidene diphenyl diphosphite, tris(mono- and di-mixed nonylphenyl)phosphite, 4,4'-isopropylidenebis(2-tert-butylphenyl)-di(nonylphenyl)phosphite, 9,10-dihydro-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-1,1,3-tetradecyl 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)octylphosphite, 2,2-methylenebis(3-methyl-4,6-di-tert-butylphenyl)2-ethylhexylphosphite, tetrakis(2,4-di-tert-butyl-5-methylphenyl)-4,4'-biphenylene diphosphite, tetrakis(2,4-di-tert-butylphenyl)-4,4'-biphenylene diphosphite, and the like.
These phosphorus-based heat stabilizers may be used alone or in combination of two or more.

Examples of the pentaerythritol type 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-t-butyl-4-methylphenyl-isodecyl-pentaerythritol diphosphite, 2,6-di-tert-butyl-4-methylphenyl-lauryl-pentaerythritol diphosphite, 2,6-di-t 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, 2,6-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, bis(2,6-di-tert-octyl-4-methylphenyl)pentaerythritol diphosphite, and the like.
These pentaerythritol-type phosphite compounds may be used alone or in combination of two or more.

When a phosphorus-based heat stabilizer is used, the content of the phosphorus-based heat stabilizer in the polyamide composition is preferably 0.01 mass % or more and 1 mass % or less, and more preferably 0.05 mass % or more and 1 mass % or less, relative to 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.

(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, 4-stearyloxy-2,2,6,6-tetramethylpiperidine, 4-cyclohexyloxy-2,2,6,6-tetramethylpiperidine, 4-benzyloxy-2,2,6,6-tetramethylpiperidine, 4-phenyl ... 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) lysyl)-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, bis(2,2,6,6-tetramethyl-4-piperidyltolylene-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-trimethyl carboxylate, tris(2,2,6,6-tetramethyl-4-piperidyl)-benzene-1,3,4-tricarboxylate, 1-[2-{3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionyloxy}butyl]-4-[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionyloxy]2,2,6,6-tetramethylpiperidine, and a condensate of 1,2,3,4-butanetetracarboxylic acid, 1,2,2,6,6-pentamethyl-4-piperidinol, and β,β,β',β'-tetramethyl-3,9-[2,4,8,10-tetraoxaspiro(5,5)undecane]diethanol.
These amine-based heat stabilizers may be used alone or in combination of two or more.

When an amine-based heat stabilizer is used, the content of the amine-based heat stabilizer in the polyamide composition is preferably 0.01 mass % or more and 1 mass % or less, and more preferably 0.05 mass % or more and 1 mass % or less, relative to 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.

(Metal salts of elements of groups 3, 4, and 11 to 14 of the periodic table)
There are no particular limitations on the metal salts of elements in Groups 3, 4, and 11 to 14 of the Periodic Table, so long as they are salts of metals belonging to these groups.
Among these, copper salts are preferred from the viewpoint of further improving the heat aging resistance of the polyamide composition, and examples of such copper salts include, but are not limited to, copper acetate, copper propionate, copper benzoate, copper adipate, copper terephthalate, copper isophthalate, copper salicylate, copper nicotinate, copper stearate, and copper complex salts in which copper is coordinated with a chelating agent.
Examples of the chelating agent include ethylenediamine and ethylenediaminetetraacetic acid.
These copper salts may be used alone or in combination of two or more.
Among them, copper acetate is preferred as the copper salt. When copper acetate is used, a polyamide composition having excellent heat aging resistance and capable of more effectively suppressing metal corrosion of the screw and cylinder part during extrusion (hereinafter, sometimes simply referred to as "metal corrosion") can be obtained.

When a copper salt is used as the heat stabilizer (G4), the content of the copper salt in the polyamide composition is preferably 0.01 mass % or more and 0.60 mass % or less, and more preferably 0.02 mass % or more and 0.40 mass % or less, relative to the total mass of the polyamide (A).
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.

From the viewpoint of improving the heat aging resistance of the polyamide composition, the content concentration of the copper element derived from the above-mentioned copper salt is preferably ¹⁰ parts by mass or more and 2,000 parts by mass or less, more preferably 30 parts by mass or more and 1,500 parts by mass or less, and even more preferably 50 parts by mass or more and 500 parts by mass or less, per 106 parts by mass (1,000,000 parts by mass) of the polyamide (A).

The components of the heat stabilizer (G4) described above may be used alone or in combination of two or more.

<Method for producing polyamide composition>
The method for producing the polyamide composition of the present embodiment is not particularly limited as long as it is a method of mixing polyamide (A) with each of the components (B) to (E) above, and, if necessary, with each of the components (F) and (G).

Examples of a method for mixing the above components (A) to (E) and, if necessary, the components (F) and (G) include the following method (1) or (2).
(1) The above components (A) to (E), and, if necessary, components (F) and (G), are mixed using a Henschel mixer or the like, and the mixture is fed to a melt kneader and kneaded.
(2) A method in which a mixture containing each of the above components (A) to (E) and, if necessary, component (G) is prepared using a single-screw or twin-screw extruder, or a method in which each of the components (A) to (E) and, if necessary, component (G) is prepared in advance by mixing using a Henschel mixer or the like, and the mixture is supplied to a melt kneader and kneaded, and then component (F) is optionally blended in through a side feeder.

The components constituting the polyamide composition may be fed to the melt kneader by feeding all of the components to the same feed port at once, or by feeding each component through a different feed port.

The melt-kneading temperature is preferably about 1° C. to 100° C. higher than the melting point of the aliphatic polyamide (A), and more preferably about 10° C. to 50° C. higher than the melting point of the aliphatic polyamide (A).
The shear rate in the kneader is preferably about 100 sec ⁻¹ or more, and the average residence time during kneading is preferably about 0.5 to 5 minutes.
The melt-kneading apparatus may be any known apparatus, and preferably used are, for example, a single-screw or twin-screw extruder, a Banbury mixer, a melt-kneader (mixing roll, etc.), etc.
The blending amount of each component when producing the polyamide composition of the present embodiment is the same as the content of each component in the polyamide composition described above.

<Molded products>
The molded article of the present embodiment is produced by molding the polyamide composition of the above embodiment.
The molded article of this embodiment has excellent flame retardancy, and is good in tensile strength, flexural modulus when absorbing water, long-term heat resistance, and creep characteristics.

The method for obtaining the molded product is not particularly limited, and any known molding method can be used.
Examples of known molding methods include extrusion molding, injection molding, vacuum molding, blow molding, injection compression molding, decorative molding, other material molding, gas-assisted injection molding, foam injection molding, low-pressure molding, ultra-thin-wall injection molding (ultra-high-speed injection molding), and in-mold composite molding (insert molding, outsert molding).

<Applications>
The molded article of the present embodiment contains the polyamide composition of the above embodiment, and has excellent flame retardancy and mechanical properties (particularly, long-term heat resistance, creep characteristics, etc.), and can be used for various applications.
The molded article of the present embodiment can be suitably used in, for example, the automotive field, the electrical and electronic field, the mechanical and industrial field, the office equipment field, and the aviation and space field.

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. Examples 1 to 15 are reference examples.

Below, we explain each component of the polyamide composition used in the present examples and comparative examples.

<Components>
[(A) Aliphatic polyamide]
A-1: Polyamide 66

[(B) Semi-aromatic polyamide]
B-1: Polyamide 6I
B-2: Polyamide 6I/6T (manufactured by EMS Co., Ltd., model number: G21, content of isophthalic acid units in all dicarboxylic acid units is 70 mol%, weight average molecular weight: 27,000)
B-3: Polyamide MXD6 (Toyobo nylon, T-600, manufactured by Toyobo Co., Ltd., isophthalic acid ratio of dicarboxylic acid unit is 0 mol%, weight average molecular weight: 45,000)

[(C) Flame retardant]
C-1: Phosphinic acid flame retardant Aluminum diethylphosphinate (manufactured by Clariant, product name: "Exolit OP1230")

[(D) Polymer containing α,β-unsaturated dicarboxylic acid anhydride as a structural unit and/or styrene-acrylonitrile copolymer]
((D1) Polymer containing α,β-unsaturated dicarboxylic acid anhydride as a structural unit)
D1-1: Maleic anhydride modified polyphenylene ether (m-PPE) (manufactured by Asahi Kasei Corporation) (molecular weight: 54,000)

((D2) Styrene-acrylonitrile copolymer)
D2-1: Styrene-acrylonitrile copolymer (AS resin) (manufactured by Asahi Kasei Corporation) (styrene unit content: 60% by mass, acrylonitrile unit content: 40% by mass, weight average molecular weight: 80,000)
D2-2: Styrene-acrylonitrile copolymer (AS resin) (manufactured by Asahi Kasei Corporation) (styrene unit content: 67% by mass, acrylonitrile unit content: 33% by mass, weight average molecular weight: 100,000)
D2-3: Styrene-acrylonitrile copolymer (AS resin) (manufactured by Asahi Kasei Corporation) (styrene unit content 70% by mass, acrylonitrile unit content 30% by mass, weight average molecular weight: 130,000)

[(D') Other polymers]
D'-1: Polyphenylene ether (PPE) (manufactured by Asahi Kasei Corporation) (molecular weight: 30,000)

[(E) Polyhydric alcohol]
E-1: Pentaerythritol (Tokyo Chemical Industry Co., Ltd., 261°C)
E-2: Dipentaerythritol (Tokyo Chemical Industry Co., Ltd., 216°C)
E-3: Tripentaerythritol (Tokyo Chemical Industry Co., Ltd., melting point 225° C.)

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

[(G) Other Additives]
G-1: Phenol-based heat stabilizer (manufactured by Ciba Specialty Chemicals, product name: "Irganox 1098")
G-2: Phosphorus-based heat stabilizer (manufactured by Ciba Specialty Chemicals, product name: "Irganox 168")

<Production of polyamide>
The production methods of the aliphatic polyamide A-1 and the semi-aromatic polyamide B-1 are described in detail below. The aliphatic polyamide A-1 and the semi-aromatic polyamide B-1 obtained by the production methods described below were dried in a nitrogen stream to adjust the moisture content to about 0.2% by mass, and then used as raw materials for the polyamide compositions in the examples and comparative examples described below.

Synthesis Example 1 Synthesis of Aliphatic Polyamide A-1 (Polyamide 66) 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 50% by mass equimolar homogeneous aqueous solution of raw material monomers. This aqueous solution was charged into an autoclave with an internal volume of 5.4 L and substituted 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 about 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 reaction was continued for 1 hour while gradually removing steam and maintaining the pressure at 1.8 MPa until the internal temperature reached 245°C. Next, the pressure was lowered over 1 hour. Next, the inside of the autoclave was maintained at a reduced pressure of 650 torr (86.66 kPa) for 10 minutes using a vacuum device. At this time, the final internal temperature of the polymerization was 265°C. The mixture was then pressurized with nitrogen to form a strand from the lower spinneret (nozzle), cooled with water, cut, and discharged in the form of pellets. The pellets were then dried at 100° C. in a nitrogen atmosphere for 12 hours to obtain aliphatic polyamide A-1 (polyamide 66).
The resulting aliphatic polyamide A-1 (polyamide 66) had Mw(A)=40,000.

Synthesis Example 2 Synthesis of Semi-aromatic Polyamide B-1 (Polyamide 6I) 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, 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 an equimolar 50 mass% homogeneous aqueous solution of raw material monomers. Next, the solution was concentrated by gradually removing steam to a solution concentration of 70 mass% while stirring at a temperature of about 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 reaction was continued for 1 hour while gradually removing steam and maintaining the pressure at 1.8 MPa until the internal temperature reached 245°C. Next, the pressure was reduced over 30 minutes. Next, the inside of the autoclave was maintained at a reduced pressure of 650 torr (86.66 kPa) for 10 minutes using a vacuum device. At this time, the final internal temperature of the polymerization was 265°C. The mixture was then pressurized with nitrogen to form a strand from the lower spinneret (nozzle), cooled with water, cut, and discharged in the form of pellets. The pellets were then dried at 100° C. in a nitrogen atmosphere for 12 hours to obtain semi-aromatic polyamide B-1 (polyamide 6I).
The resulting semi-aromatic polyamide B-1 (polyamide 6I) had a content of isophthalic acid units in dicarboxylic acid units of 100 mol % and Mw of 20,000.

<Physical properties and evaluation>
First, the pellets of the polyamide compositions obtained in the Examples and Comparative Examples were dried in a nitrogen stream to reduce the moisture content in the polyamide compositions to 500 ppm or less. Next, the pellets of each polyamide composition with the adjusted moisture content were used to carry out various physical properties and various evaluations using the following methods.

[Physical property 1] tan δ peak temperature Using a PS40E injection molding machine manufactured by Nissei Kogyo Co., Ltd., a molded article was molded according to JIS-K7139 under the injection molding conditions of a cylinder temperature of 290°C, a mold temperature of 100°C, injection for 10 seconds, and cooling for 10 seconds. This molded article was measured under the following conditions using a dynamic viscoelasticity evaluation device (EPLEXOR500N manufactured by GABO Corporation).

(Measurement conditions)
Measurement mode: Tensile Measurement frequency: 8.00 Hz
Heating rate: 3°C/min Temperature range: -100°C to 250°C

The ratio of the storage modulus e1 to the loss modulus e2 (e2/e1) was defined as tan δ, and the highest temperature was defined as the tan δ peak temperature.

[Property 2] Molecular weight (Mw) of polyamide composition
The weight average molecular weight (Mw) of the polyamide compositions obtained in the Examples and Comparative Examples was measured by GPC under the following measurement conditions.

(Measurement conditions)
Measuring device: Tosoh Corporation, HLC-8020
Solvent: Hexafluoroisopropanol solvent Standard sample: PMMA (polymethyl methacrylate) (manufactured by Polymer Laboratory) conversion GPC column: TSK-GEL GMHHR-M and G1000HHR

[Evaluation 1] Flame retardancy Measurement was performed using the method of UL94 (standard established by Under Writers Laboratories Inc., USA). The test pieces (length 127 mm, width 12.7 mm, thickness 1.6 mm) were prepared by attaching a UL test piece 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 the full filling pressure + 2% pressure when molding the UL test piece. The flame retardancy grade was evaluated according to the UL94 standard (vertical flame test) to see whether it was V-0, V-1, or V-2. The smaller the grade number, the higher the flame retardancy, and V-0 was evaluated as being flame retardant without practical problems.

[Evaluation 2] Long-term heat resistance The multipurpose test piece (A type) for the above tensile strength was heated at 180° C. in a hot air circulating oven to cause thermal aging.
After 1000 hours in the oven, the specimen was removed from the oven and cooled at 23° C. for at least 24 hours. The cooled multipurpose test specimen (A type) was then subjected to a tensile test in accordance with ASTM D638, except that the tensile speed was 5 mm/min and the chuck distance was 50 mm, in accordance with ISO 527, to measure each tensile strength. The heat aging retention rate was calculated using the following formula.

Heat resistance retention rate (%) = tensile strength after aging / tensile strength before aging x 100

[Evaluation 3] Creep properties The molded article conforming to JIS-K7139 was attached to a creep tester with a thermostatic chamber (C100-6, manufactured by Toyo Seiki Seisakusho) and a tensile creep test was carried out under conditions of an environmental temperature of 80° C. and a load of 95 MPa, and the time to break of the molded article was measured.

<Production of polyamide composition>
[Example 1] Production of polyamide composition P-1a Using a TEM35mm twin-screw extruder (set temperature: 280 ° C., screw rotation speed 300 rpm) manufactured by Toshiba Machine Co., Ltd., (A) aliphatic polyamide A-1, (B) semi-aromatic polyamide B-1, (D1) polymer D1-1 containing α,β-unsaturated dicarboxylic anhydride as a structural unit, (E) polyhydric alcohol E-1, and (G) other additives G-1 and G-2 were blended in advance and fed from a top feed port provided at the most upstream part of the extruder. In addition, (C) flame retardant C-1 and (F) filler F-1 were fed from a side feed port on the downstream side of the extruder (in a state where the resin fed from the top feed port is fully melted). Next, the molten kneaded product extruded from the die head was cooled in a strand shape and pelletized to obtain pellets of polyamide composition P-1a. The blending amounts were (A) aliphatic polyamide A-1: 25.8 mass%, (B) semi-aromatic polyamide B-1: 6.5 mass%, (C) flame retardant C-1: 10.0 mass%, (D1) polymer D1-1 containing an α,β-unsaturated dicarboxylic acid anhydride as a constituent unit: 5.0 mass%, (E) polyhydric alcohol E-2: 2.5 mass%, (F) filler F-1: 50.0 mass%, and (G) other additives G-1: 0.1 mass%, G-2: 0.1 mass%.

[Example 2] Production of polyamide composition P-2a Pellets of polyamide composition P-2a were obtained in the same manner as in Example 1, except that the blending amounts were changed to (A) aliphatic polyamide A-1: 22.5 mass % and (B) semi-aromatic polyamide B-1: 9.8 mass %.

[Example 3] Production of polyamide composition P-3a Pellets of polyamide composition P-3a were obtained in the same manner as in Example 1, except that the blending amounts were changed to (A) aliphatic polyamide A-1: 19.3 mass % and (B) semi-aromatic polyamide B-1: 13.0 mass %.

Example 4 Production of Polyamide Composition P-4a Pellets of polyamide composition P-4a were obtained in the same manner as in Example 1, except that the blending amounts were changed to (A) aliphatic polyamide A-1: 17.8% by mass, and (B) semi-aromatic polyamide B-1: 14.5% by mass.

[Example 5] Production of polyamide composition P-5a Pellets of polyamide composition P-5a were obtained in the same manner as in Example 1, except that the blending amounts were changed to (A) aliphatic polyamide A-1: 19.9 mass%, (B) semi-aromatic polyamide B-1: 13.4 mass%, and (C) flame retardant C-1: 9.0 mass%.

[Example 6] Production of polyamide composition P-6a Pellets of polyamide composition P-6a were obtained in the same manner as in Example 1, except that the blending amounts were changed to (A) aliphatic polyamide A-1: 17.5 mass%, (B) semi-aromatic polyamide B-1: 11.8 mass%, and (C) flame retardant C-1: 13.0 mass%.

Example 7 Production of Polyamide Composition P-7a Pellets of polyamide composition P-7a were obtained in the same manner as in Example 1, except that the blending amounts were changed to (A) aliphatic polyamide A-1: 21.1 mass %, (B) semi-aromatic polyamide B-1: 14.2 mass %, and (D1) polymer D1-1 containing an α,β-unsaturated dicarboxylic acid anhydride as a constituent unit: 2.0 mass %.

[Example 8] Production of polyamide composition P-8a Pellets of polyamide composition P-8a were obtained in the same manner as in Example 1, except that the blending amounts were changed to (A) aliphatic polyamide A-1: 18.1 mass%, (B) semi-aromatic polyamide B-1: 12.2 mass%, and (D1) polymer D1-1 containing an α,β-unsaturated dicarboxylic acid anhydride as a constituent unit: 7.0 mass%.

[Example 9] Production of polyamide composition P-9a Pellets of polyamide composition P-9a were obtained in the same manner as in Example 1, except that the blending amounts were changed to (A) aliphatic polyamide A-1: 20.9 mass%, (B) semi-aromatic polyamide B-1: 13.9 mass%, (D1) polymer D1-1 containing an α,β-unsaturated dicarboxylic acid anhydride as a constituent unit: 4.0 mass%, and (E) polyhydric alcohol E-2: 1.0 mass%.

[Example 10] Production of polyamide composition P-10a Pellets of polyamide composition P-10a were obtained in the same manner as in Example 1, except that the blending amounts were changed to (A) aliphatic polyamide A-1: 17.9 mass%, (B) semi-aromatic polyamide B-1: 11.9 mass%, and (E) polyhydric alcohol E-2: 5.0 mass%.

[Example 11] Production of polyamide composition P-11a Pellets of polyamide composition P-11a were obtained in the same manner as in Example 1, except that the blending amounts were changed to (A) aliphatic polyamide A-1: 16.1 mass%, (B) semi-aromatic polyamide B-2: 10.7 mass%, and (E) polyhydric alcohol E-2: 8.0 mass%.

[Example 12] Production of polyamide composition P-12a Pellets of polyamide composition P-12a were obtained in the same manner as in Example 1, except that the blending amounts were changed to (A) aliphatic polyamide A-1: 19.3 mass%, (B) semi-aromatic polyamide B-2: 13.0 mass%, and (E) polyhydric alcohol E-1: 2.5 mass%.

[Example 13] Production of polyamide composition P-13a Pellets of polyamide composition P-13a were obtained in the same manner as in Example 1, except that the blending amounts were changed to (A) aliphatic polyamide A-1: 19.3 mass%, (B) semi-aromatic polyamide B-1: 13.0 mass%, and (E) polyhydric alcohol E-3: 2.5 mass%.

[Example 14] Production of polyamide composition P-14a Pellets of polyamide composition P-14a were obtained in the same manner as in Example 1, except that the blending amounts were changed to (A) aliphatic polyamide A-1: 25.8 mass%, and (B) semi-aromatic polyamide B-2: 6.5 mass%.

[Example 15] Production of polyamide composition P-15a Pellets of polyamide composition P-15a were obtained in the same manner as in Example 1, except that the blending amounts were changed to (A) aliphatic polyamide A-1: 4.2 mass%, and (B) semi-aromatic polyamide B-3: 28.1 mass%.

[Example 16] Production of polyamide composition P-16a Pellets of polyamide composition P-16a were obtained using the same method as in Example 1, except that the blending amounts were changed to (A) aliphatic polyamide A-1: 29.8 mass%, (B) semi-aromatic polyamide B-1: 7.5 mass%, (D1) polymer D1-1 containing an α,β-unsaturated dicarboxylic acid anhydride as a constituent unit: 0 mass%, (D2) styrene copolymer D2-1: 1.0 mass%, and (E) polyhydric alcohol E-2: 1.5 mass%.

[Example 17] Production of polyamide composition P-17a Pellets of polyamide composition P-17a were obtained in the same manner as in Example 1, except that the blending amounts were changed to (A) aliphatic polyamide A-1: 29.8 mass%, (B) semi-aromatic polyamide B-1: 7.5 mass%, (D1) polymer D1-1 containing an α,β-unsaturated dicarboxylic acid anhydride as a constituent unit: 0 mass%, (D2) styrene copolymer D2-2: 1.0 mass%, and (E) polyhydric alcohol E-2: 1.5 mass%.

[Example 18] Production of polyamide composition P-18a Pellets of polyamide composition P-18a were obtained in the same manner as in Example 1, except that the blending amounts were changed to (A) aliphatic polyamide A-1: 29.8 mass%, (B) semi-aromatic polyamide B-1: 7.5 mass%, (D1) polymer D1-1 containing an α,β-unsaturated dicarboxylic acid anhydride as a constituent unit: 0 mass%, (D2) styrene copolymer D2-3: 1.0 mass%, and (E) polyhydric alcohol E-2: 1.5 mass%.

[Example 19] Production of polyamide composition P-19a Pellets of polyamide composition P-19a were obtained using the same method as in Example 1, except that the blending amounts were changed to (A) aliphatic polyamide A-1: 28.2 mass%, (B) semi-aromatic polyamide B-1: 7.1 mass%, (D1) polymer D1-1 containing an α,β-unsaturated dicarboxylic acid anhydride as a constituent unit: 0 mass%, (D2) styrene copolymer D2-2: 3.0 mass%, and (E) polyhydric alcohol E-2: 1.5 mass%.

Comparative Example 1 Production of Polyamide Composition P-1b Pellets of polyamide composition P-1b were obtained in the same manner as in Example 1, except that the blending amounts were changed to (A) aliphatic polyamide A-1: 29.4 mass%, (B) semi-aromatic polyamide B-1: 7.4 mass%, and (D1) polymer D1-1 containing an α,β-unsaturated dicarboxylic acid anhydride as a constituent unit: 0.5 mass%.

Comparative Example 2 Production of Polyamide Composition P-2b Pellets of polyamide composition P-2b were obtained in the same manner as in Example 1, except that the blending amounts were changed to (A) aliphatic polyamide A-1: 20.2 mass%, (B) semi-aromatic polyamide B-1: 5.1 mass%, and (D1) polymer D1-1 containing an α,β-unsaturated dicarboxylic acid anhydride as a constituent unit: 12.0 mass%.

Comparative Example 3 Production of Polyamide Composition P-3b Pellets of polyamide composition P-3b were obtained in the same manner as in Example 1, except that the blending amounts were changed to (A) aliphatic polyamide A-1: 29.4 mass%, (B) semi-aromatic polyamide B-2: 7.4 mass%, and (D1) polymer D1-1 containing an α,β-unsaturated dicarboxylic acid anhydride as a constituent unit: 0.5 mass%.

Comparative Example 4 Production of Polyamide Composition P-4b Pellets of polyamide composition P-4b were obtained in the same manner as in Example 1, except that the blending amounts were changed to (A) aliphatic polyamide A-1: 25.8 mass%, (B) semi-aromatic polyamide B-1: 6.5 mass%, and (D') other polymer D'-1: 5.0 mass%.

Comparative Example 5 Production of Polyamide Composition P-5b Pellets of polyamide composition P-5b were obtained in the same manner as in Example 1, except that the blending amounts were changed to (A) aliphatic polyamide A-1: 20.8 mass%, (B) semi-aromatic polyamide B-1: 14.0 mass%, and (E) polyhydric alcohol E-2: 0 mass%.

Comparative Example 6 Production of Polyamide Composition P-6b Pellets of polyamide composition P-6b were obtained in the same manner as in Example 1, except that the blending amounts were changed to (A) aliphatic polyamide A-1: 27.8 mass%, (B) semi-aromatic polyamide B-2: 7.0 mass%, and (E) polyhydric alcohol E-2: 0 mass%.

Comparative Example 7 Production of Polyamide Composition P-7b Pellets of polyamide composition P-7b were obtained in the same manner as in Example 1, except that the blending amounts were changed to (A) aliphatic polyamide A-1: 14.8% by mass, (B) semi-aromatic polyamide B-1: 10.0% by mass, and (E) polyhydric alcohol E-2: 10.0% by mass.

Comparative Example 8 Production of Polyamide Composition P-8b Pellets of polyamide composition P-8b were obtained in the same manner as in Example 1, except that the blending amounts were changed to (A) aliphatic polyamide A-1: 32.3 mass%, and (B) semi-aromatic polyamide B-1: 0 mass%.

Comparative Example 9 Production of Polyamide Composition P-9b Pellets of polyamide composition P-9b were obtained in the same manner as in Example 1, except that the blending amounts were changed to (A) aliphatic polyamide A-1: 4.5 mass%, (B) semi-aromatic polyamide B-3: 30.3 mass%, and (E) polyhydric alcohol E-2: 0 mass%.

Comparative Example 10 Production of Polyamide Composition P-10b Pellets of polyamide composition P-10b were obtained in the same manner as in Example 1, except that the blending amounts were changed to (A) aliphatic polyamide A-1: 29.7 mass%, (B) semi-aromatic polyamide B-1: 7.6 mass%, and (D1) polymer D1-1 containing an α,β-unsaturated dicarboxylic acid anhydride as a constituent unit: 0 mass%.

The resulting pellets of polyamide compositions P-1a to P-19a and P-1b to P-10b were used to produce molded articles by the above method, and various physical properties were evaluated. The evaluation results are shown in Tables 1 to 6 below.

As can be seen from Tables 1 to 4, the molded articles obtained from polyamide compositions P-1a to P-19a (Examples 1 to 19) containing components (A) to (E) and having a mass ratio (E)/(D) of 0.25 or more and less than 2.0 had excellent flame retardancy, long-term heat resistance, and creep characteristics.
In addition, in the polyamide compositions P-3a, P-9a to P-11a (Examples 3, and 9 to 11) having different contents of the (E) component and different mass ratios (E)/(D), there was a tendency for the long-term heat resistance to become better with an increase in the content of the (E) component (an increase in the value of the mass ratio (E)/(D)).
In addition, among the polyamide compositions P-3a, P-9a to P-11a (Examples 3, and 7 to 9) having different contents of the (D) component and different mass ratios (E)/(D), the polyamide compositions P-3a and P-9a having a mass ratio (E)/(D) of 0.5 or more tended to have better creep properties.

In contrast, Tables 5 and 6 show that the molded articles obtained from polyamide compositions P-1b to P-10b (Comparative Examples 1 to 10) that did not contain component (B), component (D), or component (E), or that had a mass ratio (E)/(D) of less than 0.25 or 2.0 or more, were inferior in flame retardancy, long-term heat resistance, and creep properties.

The polyamide composition of this embodiment can provide molded articles that have excellent flame retardancy, long-term heat resistance, and creep properties. The molded articles of this embodiment can be suitably used in the automotive, electrical and electronic, mechanical and industrial, office equipment, and aviation and space fields.

Claims (16)

(A) an aliphatic polyamide,
(B) a semi-aromatic polyamide containing diamine units and dicarboxylic acid units;
(C) a flame retardant,
(D) a styrene-acrylonitrile copolymer, or a polymer containing a styrene-acrylonitrile copolymer and an α,β-unsaturated dicarboxylic acid anhydride as a structural unit ; and (E) a polyhydric alcohol,
a mass ratio (E)/(D) of the content of the polyhydric alcohol (E) to the content of the styrene-acrylonitrile copolymer (D) or the styrene-acrylonitrile copolymer and the polymer containing an α,β-unsaturated dicarboxylic acid anhydride as a structural unit is 0.25 or more and less than 2.00;
The styrene-acrylonitrile copolymer contains styrene units and acrylonitrile units,
The polyamide composition has an acrylonitrile unit content of 30 mass% or more based on the total mass of the constituent units of the styrene-acrylonitrile copolymer . The polyamide composition according to claim 1, wherein the (E) polyhydric alcohol is at least one selected from the group consisting of tripentaerythritol, dipentaerythritol, and pentaerythritol. The polyamide composition according to claim 1 or 2, wherein the (C) flame retardant is a phosphorus-based flame retardant. The polyamide composition according to any one of claims 1 to 3, wherein the (C) flame retardant comprises at least one kind of phosphinate selected from the group consisting of a phosphinate represented by the following general formula (1), a diphosphinate represented by the following general formula (2), and a condensate thereof:

(In general formula (1), R ¹¹ and R ¹² each independently represent an alkyl group having 1 to 6 carbon atoms or an aryl group having 6 to 10 carbon atoms. M ⁿ¹¹⁺ represents a metal ion having a valence of n11. M represents an element belonging to Group 2 or Group 15 of the periodic table or a transition element. n11 is 2 or 3. When n11 is 2 or 3, a plurality of R ¹¹ and R ¹² may be the same or different.
In the general formula (2), R ²¹ and R ²² are each independently an alkyl group having 1 to 6 carbon atoms, or an aryl group having 6 to 10 carbon atoms. Y ²¹ is an alkylene group having 1 to 10 carbon atoms, or an arylene group having 6 to 10 carbon atoms. M' ^m21+ is a metal ion having a valence of m21. M' is an element or transition element belonging to Group 2 or Group 15 of the periodic table. n21 is an integer of 1 to 3. When n21 is 2 or 3, the multiple R ²¹ , R ²² , and Y ²¹ may be the same or different. m21 is 2 or 3. x is 1 or 2. When x is 2, the multiple M' may be the same or different. n21, x, and m21 are integers that satisfy the relationship formula 2×n21=m21×x.) The polyamide composition according to any one of claims 1 to 4, wherein the content of the flame retardant (C) is 0.1 mass% or more and 30 mass% or less relative to the mass of the polyamide composition. The (D) styrene-acrylonitrile copolymer or the polymer containing a styrene-acrylonitrile copolymer and an α,β-unsaturated dicarboxylic acid anhydride as a structural unit contains a polymer containing an α,β-unsaturated dicarboxylic acid anhydride as a structural unit,
The polyamide composition according to any one of claims 1 to 5, wherein the polymer containing an α,β-unsaturated dicarboxylic acid anhydride as a constituent unit is a maleic anhydride-modified polyphenylene ether. The polyamide composition according to any one of claims 1 to 6 , wherein the aliphatic polyamide (A) contains a diamine unit and a dicarboxylic acid unit. The polyamide composition according to any one of claims 1 to 7 , wherein the aliphatic polyamide (A) is polyamide 66. The polyamide composition according to any one of claims 1 to 8 , wherein the polyamide composition has a tan δ peak temperature of 90°C or higher. The polyamide composition according to any one of claims 1 to 9, wherein the semi-aromatic polyamide containing (B) diamine units and dicarboxylic acid units contains 50 mol % or more of isophthalic acid units in all dicarboxylic acid units constituting the semi-aromatic polyamide containing (B ) diamine units and dicarboxylic acid units. The polyamide composition according to any one of claims 1 to 10, wherein the semi-aromatic polyamide containing (B) diamine units and dicarboxylic acid units contains 75 mol % or more of isophthalic acid units in all dicarboxylic acid units constituting the semi-aromatic polyamide containing (B ) diamine units and dicarboxylic acid units. The polyamide composition according to any one of claims 1 to 11, wherein the semi-aromatic polyamide containing (B) diamine units and dicarboxylic acid units contains 100 mol % of isophthalic acid units in all dicarboxylic acid units constituting the semi-aromatic polyamide containing (B ) diamine units and dicarboxylic acid units. The polyamide composition according to any one of claims 1 to 12 , wherein the polyamide composition has a weight average molecular weight of 10,000 or more and 50,000 or less. The polyamide composition according to any one of claims 1 to 13 , further comprising at least one (F) filler. A molded article obtained by molding the polyamide composition according to any one of claims 1 to 14 . A method for producing the polyamide composition according to any one of claims 1 to 14 , comprising the steps of:
The method for producing a polyamide composition includes melt-kneading raw material components including (A) the aliphatic polyamide, (B) the semi-aromatic polyamide containing a diamine unit and a dicarboxylic acid unit, (C) the flame retardant, (D) the styrene-acrylonitrile copolymer or a polymer containing a styrene-acrylonitrile copolymer and an α,β-unsaturated dicarboxylic acid anhydride as a constituent unit , and (E) a polyhydric alcohol.