JP2024058454A - Polyamide composition and molded article - Google Patents

Abstract

The present invention provides a polyamide composition that has a low dielectric constant and is capable of forming molded articles that have good mechanical rigidity and strength, moldability, and excellent surface appearance while maintaining good impact resistance, and a molded article obtained by molding the polyamide composition.
[Solution] The polyamide composition contains (A) an aliphatic polyamide, (B) a semi-aromatic polyamide containing dicarboxylic acid units and diamine units, (C) an amorphous resin (excluding polyamide) having a glass transition temperature of 80°C or more and 250°C or less when heated at 20°C/min in differential scanning calorimetry measurement in accordance with JIS-K7121, (D) a polymer containing an α,β-unsaturated dicarboxylic acid anhydride as a constituent unit, and (E) at least one glass filler, wherein the content of the (B) semi-aromatic polyamide, the content of the (C) amorphous resin, and the relative dielectric constant of the (E) glass filler at a frequency of 1 GHz are within predetermined ranges.
[Selection diagram] None

Description

The present invention relates to a polyamide composition that has a low dielectric constant, good mechanical strength, and is capable of producing molded articles with excellent moldability and surface appearance, and to a molded article obtained by molding the polyamide composition.

Polyamides have excellent heat resistance, mechanical properties, and chemical resistance, and are therefore used in a wide range of fields, including fibers, composite materials, and electrical and electronic components. In particular, in the electrical and electronic component field, there is a demand for lighter and smaller portable electronic devices, and this has led to an increased demand for polyamides with lower dielectric constants.

The low dielectric constant of the polyamide compositions and moldings allows the use of polyamide molding compounds in housings, housing parts or other components of devices that communicate via electromagnetic waves at frequencies between 0.3 and 300 GHz without causing significant impairment to the transmission and reception characteristics of said devices. Such devices that communicate via electromagnetic waves are used in a variety of areas, such as in telecommunications or processes, in transceivers, mobile phones, tablets, laptops, navigation devices, security cameras, photographic cameras, sensors, diving computers, audio units, remote controls, speakers, headphones, radios, televisions, kitchen appliances, keyless car keys, etc.

Japanese Patent No. 6985908 discloses a polyamide which has a low relative dielectric constant and is excellent in the molding shrinkage behavior of a molded article obtained by injection molding.
These polyamides include long-chain partially crystalline aliphatic polyamides such as polyamide 12, polyamide 610, polyamide 1016, and the like, and/or long-chain amorphous polyamides such as polyamide MACM12, and the like.

JP 2010-168502 A discloses polyamides that have a low dielectric constant, low water absorption, and excellent solubility in solvents. These polyamides include polymers having repeating units of polyamides obtained by reacting a diamine having aromatic amino groups at both ends of a special bifunctional phenylene ether oligomer with a dicarboxylic acid or a dicarboxylic acid halide, or copolymers having repeating units of polyamides obtained by reacting a diamine having aromatic amino groups at both ends of a special bifunctional phenylene ether oligomer or a further diamine with a dicarboxylic acid or a dicarboxylic acid halide.

JP 05-274914 A relates to insulating materials made of polyamide resins with low dielectric constants. These materials are used in electronic components such as patch boards and multi-chip modules.

Patent No. 6985908 JP 2010-168502 A Japanese Patent Application Laid-Open No. 05-274914

Polyamide materials for the aforementioned applications are usually processed by injection molding. In addition to a low dielectric constant, the molding shrinkage behavior and surface appearance of the polyamide composition represent important properties. A low dielectric constant can be achieved by incorporating a polymer with low polarity into the polyamide composition, but due to poor compatibility with polyamide, the molding shrinkage behavior and surface appearance are adversely affected. Furthermore, polyamide molding compounds used, for example, in the field of telecommunication devices, are required to be stain-resistant, have a good surface appearance, and have excellent mechanical strength. A good mechanical strength can be achieved by incorporating a reinforcing material, such as glass fiber, into the polyamide composition, but this has an adverse effect on the dielectric constant of the polyamide composition.

The present invention has been made in consideration of the above circumstances, and provides a polyamide composition that has a low dielectric constant and is capable of forming molded articles that have good mechanical rigidity and strength, moldability, and excellent surface appearance while maintaining good impact resistance, and a molded article obtained by molding the polyamide composition.

That is, the present invention includes the following aspects.
The polyamide composition according to the present invention contains (A) an aliphatic polyamide, (B) a semi-aromatic polyamide containing a dicarboxylic acid unit and a diamine unit, (C) an amorphous resin (excluding polyamides) having a glass transition temperature of 80° C. or more and 250° C. or less when heated at a rate of 20° C./min in differential scanning calorimetry according to JIS-K7121, (D) a polymer containing an α,β-unsaturated dicarboxylic acid anhydride as a constituent unit, and (E) at least one glass filler, a content of the (B) semi-aromatic polyamide relative to the total content of the (A) aliphatic polyamide, the (B) semi-aromatic polyamide, the (C) amorphous resin, and the (D) α,β-unsaturated dicarboxylic acid anhydride [(B)/((A)+(B))] is 5 mass% or more and 60 mass% or less, a content of the (C) amorphous resin relative to the total content of the (A) aliphatic polyamide, the (B) semi-aromatic polyamide, the (C) amorphous resin, and the (D) α,β-unsaturated dicarboxylic acid anhydride [(C)/((A)+(B)+(C)+(D))] is 5 mass% or more and 50 mass% or less, and the (E) glass filler has a relative dielectric constant at a frequency of 1 GHz of 6.0 or less.
The (A) aliphatic polyamide may contain linear aliphatic dicarboxylic acid units and linear aliphatic diamine units.
The aliphatic polyamide (A) may contain an aliphatic dicarboxylic acid unit having 4 to 10 carbon atoms and an aliphatic diamine unit having 4 to 10 carbon atoms.
The aliphatic polyamide (A) may be polyamide 66.
The weight average molecular weight Mw of the (A) aliphatic polyamide may be 10,000 or more and 100,000 or less.
The semi-aromatic polyamide (B) may contain 50 mol % or more of isophthalic acid units among all dicarboxylic acid units constituting the semi-aromatic polyamide (B), and may contain, as the diamine units, diamine units having 4 to 10 carbon atoms.
The semi-aromatic polyamide (B) may contain 80 mol % or more of isophthalic acid units among all dicarboxylic acid units constituting the semi-aromatic polyamide (B), and may contain, as the diamine units, diamine units having 4 to 10 carbon atoms.
The semi-aromatic polyamide (B) may contain 100 mol % isophthalic acid units among all dicarboxylic acid units constituting the semi-aromatic polyamide (B), and may contain, as the diamine units, diamine units having 4 to 10 carbon atoms.
The semi-aromatic polyamide (B) may be polyamide 6I.
The ratio (C/N) of the number C of carbon atoms other than carbon atoms forming amide bonds to the number N of nitrogen atoms in all polyamides constituting the polyamide composition may be 5.0 or more and less than 6.0.
The content of the (C) amorphous resin relative to the total content of the (A) aliphatic polyamide, the (B) semi-aromatic polyamide, the (C) amorphous resin, and the (D) α,β-unsaturated dicarboxylic acid anhydride [(C)/((A)+(B)+(C)+(D))] may be 20 mass% or more and 50 mass% or less.
The (C) amorphous resin may be a polystyrene-based resin.
The proportion of an olefin component contained in the polystyrene-based resin may be 5% by mass or less.
The (C) amorphous resin may be a polystyrene-based resin, and the weight average molecular weight Mw of the polystyrene-based resin may be 200,500 or more.
The content of the polymer (D) containing an α,β-unsaturated dicarboxylic acid anhydride as a constituent unit may be 1 mass % or more and 8 mass % or less with respect to the total mass of the polyamide composition.
The (D) polymer containing an α,β-unsaturated dicarboxylic acid anhydride as a constituent unit may be a maleic anhydride-modified polyphenylene ether.
The (E) glass filler may be glass fiber, and the glass fiber may have a relative dielectric constant (Dk) of 5.0 or less at 1.0 GHz.
The (E) glass filler may be glass fiber, and the dielectric loss tangent (Df) may be 0.010 or less at 1.0 GHz.
The (E) glass filler may be a glass fiber, and the content of the glass fiber may be 40 mass % or more and 60 mass % or less with respect to the total mass of the polyamide composition.
The polyamide composition according to the present invention may contain additives other than the above-mentioned (A) to (E) in an amount of 5 mass % or less based on the total mass of the polyamide composition.
The molded article according to the present invention comprises the polyamide composition according to the present invention.

The polyamide composition of the above embodiment has a low dielectric constant and is capable of forming molded articles that have good mechanical rigidity and strength, moldability, and excellent surface appearance while maintaining good impact resistance, and it is also possible to form molded articles by molding the polyamide composition.

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 (A) to (E).
(A) an aliphatic polyamide;
(B) a semi-aromatic polyamide containing dicarboxylic acid units and diamine units;
(C) an amorphous resin (excluding polyamides) having a glass transition temperature of 80° C. or higher and 250° C. or lower when heated at a rate of 20° C./min in differential scanning calorimetry according to JIS-K7121;
(D) a polymer containing an α,β-unsaturated dicarboxylic acid anhydride as a constituent unit;
(E) at least one glass filler.
The content of the semi-aromatic polyamide (B) relative to the total content of the aliphatic polyamide (A) and the semi-aromatic polyamide (B) [(B)/((A)+(B))] is 5 mass% or more and 60 mass% or less, the content of the amorphous resin (C) relative to the total content of the aliphatic polyamide (A), the semi-aromatic polyamide (B), the amorphous resin (C), and the α,β-unsaturated dicarboxylic acid anhydride (D) [(C)/((A)+(B)+(C)+(D))] is 5 mass% or more and 50 mass% or less, and the relative dielectric constant of the glass filler (E) at a frequency of 1 GHz is 6.0 or less.

The polyamide composition of the present embodiment contains a polymer containing an α,β-unsaturated dicarboxylic acid anhydride (D) as a structural unit, which improves the compatibility between the aliphatic polyamide (A) and the semi-aromatic polyamide (B) and the amorphous resin (C). This allows the formation of molded articles that have a low dielectric constant and excellent impact resistance, while also exhibiting good mechanical rigidity and strength, moldability, and excellent surface appearance.
Hereinafter, each of the components of the polyamide composition of the present embodiment will be described in detail.

<(A) Aliphatic Polyamide>
The aliphatic polyamide (A) contained in the polyamide composition of the present embodiment preferably contains the following structural unit (1) or (2).
(1) (A-a) an aliphatic dicarboxylic acid unit and (A-b) an aliphatic diamine unit;
(2) (Ac) At least one selected from the group consisting of a lactam unit and an aminocarboxylic acid unit.

[(A-a) Aliphatic dicarboxylic acid unit]
Examples of the aliphatic dicarboxylic acid constituting the aliphatic dicarboxylic acid unit (A-a) include linear or branched saturated aliphatic dicarboxylic acids having from 3 to 20 carbon atoms, and linear or branched unsaturated aliphatic dicarboxylic acids having from 4 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, the aliphatic dicarboxylic acid constituting the aliphatic dicarboxylic acid unit (A-a) is preferably an aliphatic dicarboxylic acid having 4 to 10 carbon atoms, more preferably a linear aliphatic dicarboxylic acid having 4 to 10 carbon atoms, and even more preferably a linear saturated aliphatic dicarboxylic acid having 4 to 10 carbon atoms, since the polyamide composition tends to have better low dielectric constant, heat resistance, fluidity, toughness, low water absorbency, rigidity, and the like.

More preferred examples of linear saturated aliphatic dicarboxylic acids having 4 to 10 carbon atoms include succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, and sebacic acid.
Among these, as the linear saturated aliphatic dicarboxylic acid having from 4 to 10 carbon atoms, adipic acid or sebacic acid is particularly preferred from the viewpoint of the heat resistance of the polyamide composition.

[(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, branched saturated aliphatic diamines having 3 to 20 carbon atoms, linear unsaturated aliphatic diamines having 2 to 20 carbon atoms, and branched unsaturated 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), and 2,4-dimethyloctamethylenediamine.
The aliphatic diamine constituting the aliphatic diamine unit (Ab) may be used alone or in combination of two or more kinds.
Among them, the aliphatic diamine constituting the aliphatic diamine unit (A-b) is preferably a linear aliphatic diamine. The carbon number of the aliphatic diamine constituting the aliphatic diamine unit (A-b) is preferably 6 to 12, more preferably 4 to 10. When the carbon number of the aliphatic diamine constituting the aliphatic diamine unit (A-b) is equal to or more than the 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 upper limit, the crystallinity and releasability of the obtained molded article are more excellent. Furthermore, the aliphatic diamine constituting the aliphatic diamine unit (A-b) is more preferably an aliphatic diamine having a carbon number of 4 to 10.

More preferred examples of linear or branched saturated aliphatic diamines having 4 to 10 carbon atoms include tetramethylenediamine, pentamethylenediamine, hexamethylenediamine, 2-methylpentamethylenediamine, 2-methyl-1,8-octanediamine, heptamethylenediamine, octamethylenediamine, nonamethylenediamine, and decamethylenediamine.
Among these, hexamethylenediamine or 2-methyl-pentamethylenediamine is particularly preferable as the linear saturated aliphatic diamine having from 4 to 10 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 a polyvalent aliphatic amine having a valence of three or more, if necessary, within a range that does not impair the effects of the polyamide composition of this embodiment. Examples of polyvalent aliphatic amines having a valence of three or more include bishexamethylenetriamine.

[(Ac) At least one selected from the group consisting of lactam units and aminocarboxylic acid units]
The aliphatic polyamide (A) may contain at least one unit selected from the group consisting of lactam units and aminocarboxylic acid units (Ac) instead of the aliphatic dicarboxylic acid units (A-a) and the aliphatic diamine units (A-b). 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, as the lactam constituting the lactam unit or aminocarboxylic acid unit, ε-caprolactam or laurolactam is preferable, and ε-caprolactam is more preferable. 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 kind selected from the group consisting of these (Ac) lactam units and aminocarboxylic acid units may each be used alone or in combination of two or more kinds.

Among them, as the aliphatic polyamide (A) contained in the polyamide composition of this embodiment, from the viewpoint of mechanical properties, heat resistance, moldability, and toughness, polyamides containing dicarboxylic acid units and diamine units are preferred, polyamides containing aliphatic dicarboxylic acid units and aliphatic diamine units are more preferred, polyamides containing aliphatic dicarboxylic acid units having 4 to 10 carbon atoms and aliphatic diamine units having 4 to 10 carbon atoms are more preferred, polyamides containing saturated aliphatic dicarboxylic acid units having 4 to 10 carbon atoms and saturated aliphatic diamine units having 4 to 10 carbon atoms are particularly preferred, and polyamide 66 (PA66) is the most preferred. PA66 is considered to be a suitable material for automobile parts because of its excellent mechanical properties, heat resistance, moldability, and toughness.

[(A) Aliphatic polyamide content]
The content of the aliphatic polyamide (A) in the polyamide composition of this embodiment can be, for example, 10 mass% or more and less than 100 mass%, for example, 15 mass% or more and 90 mass% or less, for example, 20 mass% or more and 85 mass% or less, or for example, 30 mass% or more and 75 mass% or less, relative to the total mass of polyamide in the polyamide composition.

<(B) Semi-aromatic polyamide>
The semi-aromatic polyamide (B) contained in the polyamide composition of the present embodiment 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.

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 65 mol% or more and 100 mol% or less, even more preferably 70 mol% or more and 100 mol% or less, particularly preferably 80 mol% or more and 100 mol% or less, particularly preferably 90 mol% or more and 100 mol% or less, and most preferably 100 mol% based on all the constituent units of the semi-aromatic polyamide (B).
The proportion of the predetermined monomer unit constituting the semi-aromatic polyamide (B) can be measured by nuclear magnetic resonance spectroscopy (NMR) or the like.

[(Ba-a) 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 (B-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 70 mol% or more and 100 mol% or less, particularly preferably 80 mol% or more and 100 mol% or less, particularly preferably 90 mol% or more and 100 mol% or less, and most preferably 100 mol%.
By having the ratio of isophthalic acid units in the (Ba) dicarboxylic acid units be equal to or more than the above lower limit, a polyamide composition tends to be obtained which simultaneously satisfies mechanical properties, particularly water absorption rigidity, hot rigidity, flowability, etc. Furthermore, a molded article obtained from the polyamide composition tends to have better surface appearance.

(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, 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 tolyl group, a xylyl group, and a naphthyl group.
Examples of the arylalkyl group having 7 to 10 carbon atoms include, but are not limited to, a benzyl group.
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.

(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.

(alicyclic dicarboxylic acid unit)
Examples of alicyclic dicarboxylic acids constituting the alicyclic dicarboxylic acid unit (hereinafter sometimes referred to as "alicyclic dicarboxylic acid unit") include, but are not limited to, alicyclic dicarboxylic acids having an alicyclic structure with 3 to 10 carbon atoms. Among these, alicyclic dicarboxylic acids are preferably alicyclic dicarboxylic acids 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 as those exemplified in the above "aromatic dicarboxylic acid unit".

In the (B) semi-aromatic polyamide, the dicarboxylic acid units other than the isophthalic acid units preferably contain aromatic dicarboxylic acid units, and more preferably contain aromatic dicarboxylic acid units having 6 or more carbon atoms.
By using such a dicarboxylic acid, it is likely to be possible to obtain a polyamide composition that simultaneously satisfies mechanical properties, particularly water absorption rigidity, hot rigidity, flowability, etc. Furthermore, the surface appearance of a molded article obtained from the polyamide composition tends to be more excellent.

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.

(Aliphatic diamine unit)
Examples of the aliphatic diamine constituting the aliphatic diamine unit include 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.

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

(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 the aromatic diamine 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, it is likely to be possible to obtain a polyamide composition that simultaneously satisfies mechanical properties, particularly water absorption rigidity, hot rigidity, flowability, etc. Furthermore, the surface appearance of a molded article obtained from the polyamide composition tends to be more excellent.

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

[(B) Content of semi-aromatic polyamide]
The content of the semi-aromatic polyamide (B) in the polyamide composition of this embodiment must be 5% by mass or more and 60% by mass or less, preferably 10% by mass or more and 60% by mass or less, more preferably 20% by mass or more and 60% by mass or less, and even more preferably 25% by mass or more and 60% by mass or less, based on the total mass of polyamides in the polyamide composition (the total content of the aliphatic polyamide (A) and the semi-aromatic polyamide (B)).
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, and the surface appearance of the molded article obtained from the polyamide composition is also more excellent.

(C atoms per amide group)
In the case of polyamides formed from diamine units and dicarboxylic acid units, the number of C atoms per amide group is the sum of the C atoms between the two nitrogen atoms of the diamine (C _DS ) and the C atoms between the two carboxyl groups of the dicarboxylic acid (C _DA ), divided by 2, i.e. (C _DS +C _DA )/2. It is necessary to divide by 2 because two amide groups can be formed from two nitrogens and two carboxyl groups. For example, in the case of polyamide 66, hexamethylenediamine has 6 C atoms between the two nitrogen atoms, and adipic acid has 4 C atoms between the two carboxyl groups, so there are (6+4)/2=5 C atoms per amide group.

For polyamides formed from lactam units and aminocarboxylic acid units, the number of C atoms per amide group is equal to the number of C atoms between the nitrogen atom and the carbonyl group. For example, the number of C atoms between the nitrogen atom and the carbonyl group in polyamide 12 formed from laurinlactam is 11.

<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 terminal blocking agent include, but are not limited to, monocarboxylic acids, monoamines, acid anhydrides (e.g., phthalic anhydride), monoisocyanates, monoacid halides, monoesters, monoalcohols, etc. Only one type of terminal blocking 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 carboxyl 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 better heat resistance, fluidity, toughness, low water absorption, and rigidity.

<Method for producing (A) aliphatic polyamide and (B) semi-aromatic polyamide>
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 may include, 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; and (2) a step of polymerizing one or more selected from the group consisting of a lactam constituting a lactam unit and an aminocarboxylic acid constituting an aminocarboxylic acid unit 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, sometimes 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-state polymerization method").
3) A method of polymerizing one or more selected from the group consisting of dicarboxylic acid-diamine salts, mixtures of dicarboxylic acids and diamines, lactams, and aminocarboxylic acids while maintaining the solid state (hereinafter, sometimes referred to as "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, the specific method for producing polyamide is preferably a production method including 1) a hot melt polymerization method. In addition, when producing polyamide by the hot melt polymerization method, it is preferable to maintain the molten state until the polymerization is completed. In order to maintain the molten state, it is necessary to produce the polyamide composition under polymerization conditions suitable for the composition. 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 the polyamide is not particularly limited, and any known apparatus 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 concentrated solution obtained is then transferred to an autoclave, and heating is continued until the pressure in the autoclave becomes about 1.2 MPa or more and 2.2 MPa or less (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 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 in the autoclave is reduced to atmospheric pressure, the pressure can be reduced as necessary to effectively remove the by-produced water.
The autoclave is then pressurized with an inert gas such as nitrogen, and the polyamide melt is extruded from the autoclave as a strand. The extruded strand is cooled and cut to obtain polyamide pellets.

<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) amino terminus, 2) carboxyl terminus, 3) terminus with a capping agent, and 4) 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 carboxyl terminal is a polymer terminal having a carboxyl group (--COOH group) and is derived from a dicarboxylic acid.
3) The term "terminal end by a capping agent" refers to an end formed when a capping agent is added during polymerization. Examples of the capping agent include the above-mentioned terminal capping agents.
4) "Other ends" are polymer ends that are not classified into the above-mentioned 1) to 3). Specific examples of other ends include ends generated by deammoniating an amino end, ends generated by decarboxylating a carboxyl end, etc.

<Characteristics of polyamide>
[(A) Characteristics of Aliphatic Polyamide]
The molecular weight, molecular weight distribution, melting point Tm2, crystallization enthalpy ΔH and tan δ peak temperature of the aliphatic polyamide (A) can be as follows, and specifically, can be measured by the methods shown below.

((A) Weight average molecular weight Mw(A) of aliphatic polyamide)
The weight average molecular weight can be used as an index of the molecular weight of the aliphatic polyamide (A). The weight average molecular weight (Mw(A)) of the aliphatic polyamide (A) is preferably 10,000 to 100,000, more preferably 10,000 to 50,000, even more preferably 15,000 to 45,000, still more preferably 20,000 to 40,000, and particularly preferably 25,000 to 35,000.
By setting Mw(A) within the above range, a polyamide composition tends to be obtained which simultaneously satisfies mechanical properties, particularly water absorption rigidity, hot rigidity, flowability, etc. Furthermore, a molded article obtained from the polyamide composition has a more excellent surface appearance.
The weight average molecular weight (Mw(A)) of the aliphatic polyamide (A) can be measured by using GPC (gel permeation chromatography).

(A) Molecular Weight Distribution of Aliphatic Polyamide)
The molecular weight distribution of the aliphatic polyamide (A) is indicated by the weight average molecular weight (Mw(A)) of the aliphatic polyamide (A) / the number average molecular weight (Mn(A)) of the aliphatic polyamide (A).
Mw(A)/Mn(A) is 1.0 or more, preferably 1.8 or more and 2.2 or less, and more preferably 1.9 or more and 2.1 or less.
When Mw(A)/Mn(A) is in the above range, a polyamide composition having excellent flowability, etc. can be obtained. In addition, a molded article obtained from the polyamide composition has an excellent surface appearance.
Examples of methods for controlling Mw(A)/Mn(A) within the above range include the following methods 1) and 2).
1) A method in which a known polycondensation catalyst such as phosphoric acid or sodium hypophosphite is added as an additive during the hot melt polymerization of polyamide.
2) In addition to the above method 1), a method of controlling polymerization conditions such as heating conditions and reduced pressure conditions.

The molecular weight distribution (Mw(A)/Mn(A)) of the aliphatic polyamide (A) can be calculated using Mw(A) and Mn(A) obtained using GPC.

((A) Melting point Tm2 of aliphatic polyamide)
The lower limit of the melting point Tm2 of the aliphatic polyamide (A) is preferably 220° C., more preferably 230° C., and even more preferably 240° C. On the other hand, the upper limit of the melting point Tm2 of the aliphatic polyamide (A) is preferably 300° C., more preferably 290° C., even more preferably 280° C., and particularly preferably 270° C.
That is, the melting point Tm2 of the aliphatic polyamide (A) is preferably 220°C or more and 300°C or less, more preferably 230°C or more and 290°C or less, even more preferably 240°C or more and 280°C or less, and particularly preferably 240°C or more and 270°C or less.
When the melting point Tm2 of the aliphatic polyamide (A) is equal to or higher than the lower limit, the molded article obtained from the polyamide composition tends to have better hot rigidity, etc. On the other hand, when the melting point Tm2 of the aliphatic polyamide (A) is equal to or lower than the upper limit, the thermal decomposition of the polyamide composition during melt processing such as extrusion and molding tends to be more suppressed.

((A) Crystallization enthalpy ΔH of aliphatic polyamide)
The lower limit of the crystallization enthalpy ΔH of the aliphatic polyamide (A) is preferably 30 J/g, more preferably 40 J/g, further preferably 50 J/g, and particularly preferably 60 J/g, from the viewpoint of mechanical properties, particularly water absorption rigidity and hot rigidity. On the other hand, the upper limit of the crystallization enthalpy ΔH of the aliphatic polyamide (A) is not particularly limited, and the higher the value, the more preferable.
(A) An example of an apparatus for measuring the melting point Tm2 and crystallization enthalpy ΔH of an aliphatic polyamide is Diamond-DSC manufactured by PERKIN-ELMER.

((A) tan δ peak temperature of aliphatic polyamide)
The tan δ peak temperature of the aliphatic polyamide (A) is preferably 40°C or higher, more preferably 50°C or higher and 110°C or lower, even more preferably 60°C or higher and 100°C or lower, particularly preferably 70°C or higher and 95°C or lower, and most preferably 80°C or higher and 90°C or lower.
When the tan δ peak temperature of the aliphatic polyamide (A) is equal to or higher than the above lower limit, the water absorption rigidity and hot rigidity of a molded article obtained from the polyamide composition tend to be superior.
The tan δ peak temperature of the aliphatic polyamide (A) can be measured using a viscoelasticity measuring analyzer or the like (DVE-V4, manufactured by Rheology Co., Ltd.).

[(B) Characteristics of Semi-aromatic Polyamide]
The molecular weight, molecular weight distribution, formic acid relative viscosity (VR(B)), melting point Tm2, crystallization enthalpy ΔH, tan δ peak temperature, amino terminal amount, and carboxy terminal amount of the semi-aromatic polyamide (B) can be as follows, and specifically, can be measured by the method shown below.

((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)) of the semi-aromatic polyamide (B) can be used.
The weight average molecular weight (Mw(B)) of the semi-aromatic polyamide (B) can be 10,000 or more and 50,000 or less, preferably 10,000 or more and 40,000 or less, more preferably 10,000 or more and 35,000 or less, even more preferably 15,000 or more and 30,000 or less, and particularly preferably 20,000 or more and 27,000 or less.
When the weight average molecular weight (Mw(B)) of the semi-aromatic polyamide (B) is within the above range, a polyamide composition having excellent mechanical properties, particularly excellent water absorption rigidity, hot rigidity, flowability, etc. is obtained. In addition, a molded article obtained from the polyamide composition has an excellent surface appearance.
The weight average molecular weight (Mw(B)) of the semi-aromatic polyamide (B) can be measured by GPC.

(B) Molecular Weight Distribution of Semi-Aromatic Polyamide)
The molecular weight distribution of the semi-aromatic polyamide (B) is indicated by the weight average molecular weight (Mw(B)) of the semi-aromatic polyamide (B) / the number average molecular weight (Mn(B)) of the semi-aromatic polyamide (B).
Mw(B)/Mn(B) is 2.4 or less, preferably 1.0 or more and 2.4 or less, more preferably 1.7 or more and 2.4 or less, even more preferably 1.8 or more and 2.3 or less, particularly preferably 1.9 or more and 2.2 or less, and most preferably 2.0 or more and 2.2 or less.
When Mw(B)/Mn(B) is in the above range, a polyamide composition having more excellent flowability, etc. can be obtained. In addition, a molded article obtained from the polyamide composition has more excellent surface appearance.

Examples of the method for controlling Mw(B)/Mn(B) within the above range include the following methods 1) and 2).
1) A method in which a known polycondensation catalyst such as phosphoric acid or sodium hypophosphite is added as an additive during the hot melt polymerization of polyamide.
2) In addition to the above method 1), a method in which polymerization conditions such as heating conditions and reduced pressure conditions are controlled to complete the polycondensation reaction at as low a temperature as possible and in as short a time as possible.

In particular, if the semi-aromatic polyamide (B) is an amorphous polyamide, it is desirable since it has no melting point and therefore the reaction temperature can be lowered.
When the molecular structure of a polyamide contains aromatic compound units, the molecular weight distribution (Mw/Mn) tends to increase with increasing molecular weight. A high molecular weight distribution indicates a high proportion of polyamide molecules having a three-dimensional molecular structure. Therefore, by controlling Mw(B)/Mn(B) within the above range, the progress of three-dimensional molecular structuring during high-temperature processing is suppressed, and a polyamide composition with excellent flowability and the like can be obtained. In addition, the surface appearance of a molded article obtained from the polyamide composition is improved.
The Mw(B)/Mn(B) ratio can be calculated using Mw(B) and Mn(B) obtained by GPC.

((B) Formic Acid Relative Viscosity (VR(B)) of Semi-Aromatic Polyamides
In this specification, the formic acid relative viscosity (VR) of the semi-aromatic polyamide (B) is the relative viscosity of a formic acid solution of the semi-aromatic polyamide (B), and can be said to be the relative viscosity obtained by comparing the viscosity of the formic acid solution of the semi-aromatic polyamide (B) with the viscosity of formic acid itself.
In this specification, the VR(B) is an index of the molecular weight and fluidity of the semi-aromatic polyamide (B), and the higher the VR(B) value, the higher the molecular weight and the lower the fluidity.
VR(B) is measured in accordance with ASTM-D 789. Specifically, a solution in which the semi-aromatic polyamide (B) is dissolved in 90% by mass of formic acid (10% by mass of water) to give a concentration of 8.4% by mass is used, and a value measured at 25° C. can be used as the VR(B) value.
VR(B) of the semi-aromatic polyamide (B) is preferably 8 or more and 30 or less, more preferably 8 or more and 27 or less, even more preferably 10 or more and 25 or less, and particularly preferably 10 or more and 20 or less.
When the VR(B) of the semi-aromatic polyamide (B) is equal to or greater than the lower limit, the color tone and mechanical properties tend to be better, whereas when the VR(B) of the semi-aromatic polyamide (B) is equal to or less than the upper limit, the flowability and moldability tend to be better.

(B) Crystallization enthalpy ΔH of semi-aromatic polyamide
(B) The crystallization enthalpy ΔH of the semi-aromatic polyamide is preferably 15 J/g or less, more preferably 10 J/g or less, even more preferably 5 J/g or less, and particularly preferably 0 J/g, from the viewpoint of mechanical properties, particularly water absorption rigidity and hot rigidity.
As a method for controlling the crystallization enthalpy ΔH of the (B) semi-aromatic polyamide within the above range, a method for reducing the crystallinity of a known polyamide can be used, and is not particularly limited. Specific examples of a method for reducing the crystallinity of a known polyamide include a method for increasing the ratio of meta-substituted aromatic dicarboxylic acid units to dicarboxylic acid units and a method for increasing the ratio of meta-substituted aromatic diamine units to diamine units. From this viewpoint, the (B) semi-aromatic polyamide preferably contains 50 mol% or more of isophthalic acid as the (B-a) dicarboxylic acid unit, more preferably 75 mol%, and even more preferably 100 mol% of isophthalic acid in all dicarboxylic acid units constituting the (B) semi-aromatic polyamide.
(B) An example of an apparatus for measuring the crystallization enthalpy ΔH of a semi-aromatic polyamide is Diamond-DSC manufactured by PERKIN-ELMER.

(B) Tan δ Peak Temperature of Semi-Aromatic Polyamide)
The tan δ peak temperature of the semi-aromatic polyamide (B) is preferably 70°C or higher, more preferably 100°C or higher and 160°C or lower, even more preferably 110°C or higher and 150°C or lower, particularly preferably 120°C or higher and 145°C or lower, and most preferably 130°C or higher and 140°C or lower.
(B) When the tan δ peak temperature of the semi-aromatic polyamide is equal to or higher than the lower limit, a polyamide composition having excellent water absorption rigidity and hot rigidity can be obtained. Also, when the tan δ peak temperature of the polyamide composition is equal to or lower than the upper limit, the surface appearance of the molded article obtained from the polyamide composition is excellent.
Examples of the method for controlling the tan δ peak temperature of the semi-aromatic polyamide (B) within the above range include a method for increasing the ratio of aromatic monomers to dicarboxylic acid units, etc. From this viewpoint, the semi-aromatic polyamide (B) preferably contains, as dicarboxylic acid units (Ba-a), 50 mol % or more, more preferably 100 mol % of isophthalic acid in all dicarboxylic acid units constituting the semi-aromatic polyamide (B).
The tan δ peak temperature of the semi-aromatic polyamide (B) can be measured, for example, using a viscoelasticity measuring analyzer (DVE-V4, manufactured by Rheology Co., Ltd.).

((B) Amount of Amino Terminal Groups in Semi-Aromatic Polyamide)
The amount of amino terminals in the semi-aromatic polyamide (B) is preferably 5 μg or more and 100 μg or less, more preferably 10 μg or more and 90 μg or less, even more preferably 20 μg or more and 80 μg or less, particularly preferably 30 μg or more and 70 μg or less, and most preferably 40 μg or more and 60 μg or less, per 1 g of the semi-aromatic polyamide (B).
When the amino terminal amount of the semi-aromatic polyamide (B) is within the above range, a polyamide composition which is more resistant to discoloration due to heat or light can be obtained.
The amount of amino terminal can be measured by neutralization titration.

((B) Amount of Carboxyl Terminal Groups in Semi-Aromatic Polyamide)
The amount of carboxyl terminals of the semi-aromatic polyamide (B) is from 50 μg to 300 μg, preferably from 100 μg to 280 μg, more preferably from 150 μg to 260 μg, even more preferably from 180 μg to 250 μg, and particularly preferably from 190 μg to 240 μg, per 1 g of the semi-aromatic polyamide (B).
(B) When the amount of carboxyl terminals of the semi-aromatic polyamide is within the above range, a polyamide composition having excellent flowability, etc. is obtained. In addition, the surface appearance of a molded article obtained from the polyamide composition is improved.
The amount of carboxyl terminals can be measured by neutralization titration.

[(A) Difference between weight average molecular weight Mw(A) of aliphatic polyamide and (B) weight average molecular weight Mw(B) of semi-aromatic polyamide {Mw(A) - Mw(B)}]
The difference between the weight average molecular weight Mw(A) of the aliphatic polyamide (A) and the weight average molecular weight Mw(B) of the semi-aromatic polyamide (B), {Mw(A) - Mw(B)}, is preferably 5,000 or more, more preferably 6,000 or more, even more preferably 7,000 or more, particularly preferably 7,500 or more, and most preferably 8,000 or more.
When {Mw(A) - Mw(B)} is equal to or greater than the above lower limit, the semi-aromatic polyamide (B) forms micro-size domains, resulting in a composition that is superior in water absorption rigidity and hot rigidity.

[Total Amount of Amino Terminal and Carboxyl Terminal of Polyamide]
The total amount of amino terminals and carboxyl terminals of the polyamide ((A) aliphatic polyamide and (B) semi-aromatic polyamide) is 150 μg or more and 350 μg or less, preferably 160 μg or more and 330 μg or less, more preferably 170 μg or more and 320 μg or less, even more preferably 180 μg or more and 300 μg or less, and particularly preferably 190 μg or more and 280 μg or less, per gram of polyamide.
When the total amount of amino terminals and carboxyl terminals of the polyamide ((A) aliphatic polyamide and (B) semi-aromatic polyamide) is within the above range, a polyamide composition having superior flowability, etc. is obtained. In addition, the surface appearance of a molded article obtained from the polyamide composition is superior.

[Ratio (C/N) of the number of carbon atoms other than carbon atoms forming amide bonds to the number of nitrogen atoms N of polyamide]
The ratio (C/N) of the number of carbon atoms C other than carbon atoms forming amide bonds to the number of nitrogen atoms N in all polyamides constituting the polyamide composition is preferably 3.0 or more and 9.0 or less, more preferably 4.0 or more and 8.0 or less, even more preferably 4.5 or more and 7.0 or less, particularly preferably 5.0 or more and 6.5 or less, and most preferably 5.0 or more and less than 6.0.
When the ratio (C/N) of the number of carbon atoms C other than those forming amide bonds to the number of nitrogen atoms N in all polyamides constituting the polyamide composition is within the above range, a polyamide composition having better flowability, etc. is obtained. In addition, the surface appearance of a molded article obtained from the polyamide composition is better.

<(C) Amorphous Resin>
The amorphous resin (C) contained in the polyamide composition of the present embodiment is not particularly limited as long as it has a glass transition temperature of 80° C. or higher and 250° C. or lower when heated at a rate of 20° C./min in differential scanning calorimetry according to JIS-K7121 and is excluding polyamides.
In differential scanning calorimetry measurement in accordance with JIS-K7121, the amorphous resin (C) has a glass transition temperature obtained when the temperature is increased at 20° C./min. from 80° C. to 250° C., preferably from 85° C. to 250° C., more preferably from 85° C. to 220° C., still more preferably from 85° C. to 200° C., and particularly preferably from 90° C. to 180° C.
When the glass transition temperature of the (C) amorphous resin is within the above range, a polyamide composition can be obtained that has a low dielectric constant and excellent mechanical properties, particularly hot rigidity, impact resistance, flowability, etc. In addition, a molded article obtained from the polyamide composition has an excellent surface appearance.

Specific examples of such (C) amorphous resin include polystyrene-based resins, acrylic-based resins, and polyether-based resins.
Examples of polystyrene resins include atactic polystyrene, isotactic polystyrene, syndiotactic polystyrene, acrylonitrile-styrene copolymer (hereinafter sometimes abbreviated as "AS") resin, and acrylonitrile-butadiene-styrene copolymer (hereinafter sometimes abbreviated as "ABS") resin.
Examples of polyether resins include polycarbonate, polyphenylene ether, polysulfone, and polyethersulfone.
Examples of acrylic resins include polyacrylic acid, polyacrylic acid esters, and polymethyl methacrylate (polymethyl methacrylate).
These amorphous resins (C) may be used alone or in combination of two or more.
Among these, the amorphous resin (C) is preferably a polystyrene-based resin, and more preferably atactic polystyrene or syndiotactic polystyrene.

As the (C) amorphous resin in the polyamide composition of this embodiment, a polystyrene-based resin is preferred, and the proportion of the olefin component contained in the polystyrene-based resin is preferably 5% by mass or less, more preferably 4% by mass or less, even more preferably 2% by mass or less, and particularly preferably 0%. In addition, the proportion of styrene units to the total mass of the polystyrene-based resin is preferably 95% by mass or more, more preferably 96% by mass or more, even more preferably 98% by mass or more, and particularly preferably 100%.

[Content of (C) amorphous resin]
In the polyamide composition of this embodiment, the content of the amorphous resin (C) relative to the total content of the aliphatic polyamide (A), the semi-aromatic polyamide (B), the amorphous resin (C), and the α,β-unsaturated dicarboxylic acid anhydride (D) [(C)/((A)+(B)+(C)+(D))] must be 5% by mass or more and 50% by mass or less, preferably 10% by mass or more and 50% by mass or less, more preferably 15% by mass or more and 50% by mass or less, and even more preferably 20% by mass or more and 50% by mass or less.
The content of the amorphous resin (C) in the polyamide composition of this embodiment is preferably 5% by mass or more and 50% by mass or less, more preferably 10% by mass or more and 50% by mass or less, and particularly preferably 30% by mass or more and 50% by mass or less, based on the total mass of the aliphatic polyamide (A), the semi-aromatic polyamide (B), and the amorphous resin (C).
By setting the content of the (C) amorphous resin to the above lower limit or more, a polyamide composition having a low relative dielectric constant, impact resistance, and mechanical strength can be obtained. On the other hand, by setting the content of the (C) amorphous resin to the above upper limit or less, the generation of decomposition gas during melt kneading, the decrease in fluidity during molding, and the adhesion of contaminants to the molding die can be more effectively suppressed, and a molded product having a good surface appearance can be obtained. Furthermore, the deterioration of mechanical properties such as toughness and rigidity and the appearance of the molded product can be more effectively suppressed.

[(C) Characteristics of amorphous resin]
((C) Weight average molecular weight Mw(C) of amorphous resin)
As an index of the molecular weight of the (C) amorphous resin, the weight average molecular weight (Mw(C)) of the (C) amorphous resin can be used.

The weight average molecular weight (Mw(C)) of the amorphous resin (C) is preferably from 10,000 to 500,000, more preferably from 50,000 to 400,000, even more preferably from 100,000 to 300,000, particularly preferably from 200,000 to 280,000, and most preferably from 200,500 to 250,000.
When the weight average molecular weight (Mw(C)) of the (C) amorphous resin is within the above range, a polyamide composition can be obtained that has a low dielectric constant and excellent mechanical properties, particularly water absorption rigidity, hot rigidity, flowability, etc. In addition, a molded article obtained from the polyamide composition has an excellent surface appearance.

The weight average molecular weight (Mw(C)) of the amorphous resin (C) can be measured using GPC (gel permeation chromatography).

((C) Crystallization enthalpy ΔH of amorphous resin)
(C) The crystallization enthalpy ΔH of the amorphous resin is preferably 0 J/g or more and 15 J/g or less, more preferably 0 J/g or more and 10 J/g or less, and even more preferably 0 J/g or more and 5 J/g or less, from the viewpoints of mechanical properties, particularly water absorption rigidity and hot rigidity.
(C) An example of an apparatus for measuring the glass transition temperature and ΔH of the amorphous resin is Diamond-DSC manufactured by PERKIN-ELMER.

<(D) Polymer Containing α,β-Unsaturated Dicarboxylic Acid Anhydride Unit>
The polyamide composition of the present embodiment contains (G) a polymer containing an α,β-unsaturated dicarboxylic acid anhydride unit, and thus can be a polyamide composition having superior mechanical properties such as impact resistance and rigidity.
(D) Examples of the polymer containing an α,β-unsaturated dicarboxylic acid anhydride unit 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 (I) (hereinafter, sometimes referred to as "compound (I)").

In the general formula (I), R ¹¹ and R ¹² are each independently a hydrogen atom or an alkyl group having 1 to 3 carbon atoms. R ¹¹ and R ¹² may be the same or different. In particular, it is preferable that R ¹¹ and R ¹² are the same from the viewpoint of ease of production.
Examples of the alkyl group having 1 to 3 carbon atoms for R ¹¹ and R ¹² include a methyl group, an ethyl group, a propyl group, and an isopropyl group.
Among these, R ¹¹ and R ¹² are preferably a hydrogen atom or a methyl group, and more preferably a hydrogen atom.

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

[Copolymer of aromatic vinyl compound and α,β-unsaturated dicarboxylic acid anhydride]
As the polymer containing an α,β-unsaturated dicarboxylic acid anhydride as a copolymerization component, from the viewpoint of the efficiency of improving the appearance (which is achieved even with a small addition amount), a copolymer of an aromatic vinyl compound and an α,β-unsaturated dicarboxylic acid anhydride is preferred.
Examples of aromatic vinyl compounds used in the production of copolymers of aromatic vinyl compounds and α,β-unsaturated dicarboxylic acid anhydrides include compounds represented by the following general formula (II) (hereinafter, sometimes referred to as "compound (II)").

In the general formula (II), ^R21 is hydrogen or an alkyl group having 1 to 3 carbon atoms. ^R22 is a substituent of a benzene ring. ^R22 is an alkyl group having 1 to 3 carbon atoms. n21 is an integer of 0 to 5. When n21 is 0, the benzene ring is unsubstituted.

Examples of the alkyl group having 1 to 3 carbon atoms in R ²¹ and R ²² include the same groups as those exemplified in compound (I) above.
Among them, R ²¹ is preferably a hydrogen atom or a methyl group, and R ²² is preferably a methyl group.

n21 represents the number of R ²² which is a substituent of a benzene ring. n21 is preferably an integer of 0 or more and 1 or less, and more preferably 0.

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

When the polymer containing (D) α,β-unsaturated dicarboxylic anhydride units contains aromatic vinyl compound units, the aromatic vinyl compound units have affinity with (C) amorphous resin (polystyrene, etc.), and the α,β-unsaturated dicarboxylic anhydride units have affinity with or react with polyamide. This is thought to help disperse (C) amorphous resin in the polyamide matrix.

The ratio of aromatic vinyl compound units and α,β-unsaturated dicarboxylic anhydride units in the copolymer of aromatic vinyl compound and α,β-unsaturated dicarboxylic anhydride is preferably 50% by mass or more and 99% by mass or less, and 0.1% by mass or more and 50% by mass or less, based on the total structural units of the copolymer of aromatic vinyl compound and α,β-unsaturated dicarboxylic anhydride, from the viewpoint of the fluidity, thermal decomposition resistance, etc. of the obtained polyamide composition. The ratio of α,β-unsaturated dicarboxylic anhydride units in the copolymer of aromatic vinyl compound and α,β-unsaturated dicarboxylic anhydride is more preferably 0.1% by mass or more and 20% by mass or less, and even more preferably 0.2% by mass or more and 10% by mass or less, based on the total structural units of the copolymer of aromatic vinyl compound and α,β-unsaturated dicarboxylic anhydride.
When 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 equal to or greater than the above lower limit, a polyamide composition having more excellent mechanical properties such as toughness and rigidity can be obtained. On the other hand, when the proportion of α,β-unsaturated dicarboxylic anhydride units is equal to or less than the above upper limit, deterioration of the polyamide composition caused by the α,β-unsaturated dicarboxylic anhydride can be more effectively prevented.

[Polymer modified with α,β-unsaturated dicarboxylic acid anhydride]
Examples of the polymer modified with an α,β-unsaturated dicarboxylic anhydride include polyphenylene ether and polypropylene modified with an α,β-unsaturated dicarboxylic anhydride. Among them, the polymer modified with an α,β-unsaturated dicarboxylic anhydride is preferably maleic anhydride-modified polyphenylene ether.

[Content of (D) Polymer Containing α,β-Unsaturated Dicarboxylic Anhydride Unit]
The content of the polymer (D) containing an α,β-unsaturated dicarboxylic acid anhydride unit in the polyamide composition of this embodiment is preferably 0.1 mass % or more and 20 mass % or less, more preferably 0.5 mass % or more and 15 mass % or less, even more preferably 1 mass % or more and 10 mass % or less, still more preferably 1 mass % or more and 8 mass % or less, and particularly preferably 1 mass % or more and 5 mass % or less, relative to the total mass of the polyamide composition.
By the content of the polymer containing (D) α,β-unsaturated dicarboxylic anhydride units being equal to or greater than the lower limit, the dispersion effect of the (C) amorphous resin in the polyamide composition due to compatibilization can be further enhanced. In addition, there is a tendency that a polyamide composition having a more excellent effect of improving surface appearance and rigidity can be obtained. In addition, by the content of the polymer containing (D) α,β-unsaturated dicarboxylic anhydride units being equal to or less than the upper limit, there is a tendency that a polyamide composition having a more excellent strength, etc. can be obtained without impairing the properties of the polyamide, such as dielectric constant, mechanical properties (especially toughness, rigidity), etc.

<(E) Glass filler>
The polyamide composition of the present embodiment further contains (E) a glass filler in addition to the above-mentioned components (A) to (D). By containing (E) a glass filler, the polyamide composition can have more excellent mechanical properties such as toughness and rigidity.

Examples of the glass filler (E) contained in the polyamide composition of the present embodiment include glass fibers, glass flakes, and glass beads.
These glass fillers (E) may be used alone or in combination of two or more.
Among these, glass fiber is preferred as the (E) glass filler from the viewpoints of rigidity, strength, and the like.

(E) When the glass filler is glass fiber, it is preferable that the number average fiber diameter (d) is 3 μm or more and 30 μm or less. It is also preferable that the weight average fiber length (L) is 100 μm or more and 750 μm or less. Furthermore, it is preferable that the aspect ratio ((L)/(d)) of the number average fiber diameter (d) to the weight average fiber length (L) is 10 or more and 100 or less. By using glass fiber or carbon fiber of the above configuration, it is possible to develop higher characteristics.

When the (E) glass filler is glass fiber, it is more preferable that the number average fiber diameter (d) is 3 μm or more and 30 μm or less. It is more preferable that the weight average fiber length (L) is 103 μm or more and 500 μm or less. Furthermore, it is more preferable that the aspect ratio ((L)/(d)) is 3 or more and 100 or less.

(E) The number average fiber diameter and weight average fiber length of the glass filler can be measured by the following method.
First, the resin component of a molded product of a polyamide composition is melted at a high temperature of 450° C. or more. Next, from the obtained ash component, for example, 100 or more glass fibers are arbitrarily selected. Next, the glass fibers are observed with an optical microscope, a scanning electron microscope, or the like to determine the glass fiber composition.

The relative dielectric constant (Dk) of the (E) glass filler at a frequency of 1.0 GHz can be measured by a cavity resonance method using a network analyzer, and is 6.0 or less, and preferably 5.0 or less. The dielectric loss tangent (Df) of the (E) glass filler at a frequency of 1.0 GHz is preferably 0.010 or less, more preferably 0.001 or more and 0.010 or less, and even more preferably 0.001 or more and 0.005 or less.

[(E) Glass filler content]
When the polyamide composition of the present embodiment contains a glass filler (E), the content of the glass filler (E) in the polyamide composition is preferably from 1 to 80% by mass, more preferably from 10 to 70% by mass, even more preferably from 30 to 70% by mass, particularly preferably from 30 to 60% by mass, and most preferably from 40 to 60% by mass, relative to the total mass of the polyamide composition.
When the content of the (E) glass 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 (E) glass filler is equal to or less than the above upper limit, a polyamide composition having a lower relative dielectric constant and dielectric loss tangent and a polyamide composition having better moldability tend to be obtained.
In particular, when the (E) glass filler is glass fiber and the content of the (E) glass filler is in the above-mentioned range relative to the total mass of the polyamide composition, the polyamide composition tends to have further improved mechanical properties such as strength and rigidity while maintaining a low dielectric constant.

<(F) Other Additives>
In addition to the above components (A) to (E), the polyamide composition of this embodiment may also contain (F) other additives commonly used in polyamides, provided that the effects of the polyamide composition of this embodiment are not impaired. Examples of (F) other additives include (F1) moldability improvers (hereinafter also referred to as "lubricants"), (F2) deterioration inhibitors, (F3) nucleating agents, and (F4) heat stabilizers.
When the polyamide composition of this embodiment contains other additives (F), the content of other additives (F) in the polyamide composition of this 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 this embodiment; however, 0% by mass or more and 5% by mass or less is preferable, 0.01% by mass or more and 4.0% by mass or less is more preferable, 0.1% by mass or more and 3.0% by mass or less is even more preferable, and 0.5% by mass or more and 2.5% by mass or less is particularly preferable.

[(F1) Moldability improver]
The moldability improver (F1) that can be contained in the polyamide composition of the present embodiment is not particularly limited, but examples thereof include higher fatty acids, higher fatty acid metal salts, higher fatty acid esters, and higher fatty acid amides.

(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 saturated aliphatic monocarboxylic acid having 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, Group 1 elements, Group 2 elements in the Periodic Table, 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.

[(F2) Deterioration inhibitor]
The deterioration inhibitor (F2) that may be contained in the polyamide composition of the present embodiment is used for the purpose of preventing thermal deterioration and discoloration when heated, and improving heat aging resistance.
The deterioration inhibitor (F2) 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 (F2) may be used alone or in combination of two or more.

[(F3) Nucleating Agent]
(F3) 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 or more uniform in size.

Examples of the nucleating agent (F3) include, but are not limited to, talc, boron nitride, mica, kaolin, silicon nitride, carbon black, potassium titanate, and molybdenum disulfide.
The nucleating agent (F3) may be used alone or in combination of two or more kinds.
Among these, as the nucleating agent (F3), talc or boron nitride is preferred from the viewpoint of nucleating agent effect.

In addition, since the effect of the nucleating agent is high, the number average particle size of the nucleating agent (F3) 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 part by mass or more and 1 part by mass or less, more preferably 0.001 part by mass or more and 0.5 part by mass or less, and even more preferably 0.001 part by mass or more and 0.1 part 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, while 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.

[(F4) Heat stabilizer]
Examples of the heat stabilizer (F4) include, but are not limited to, phenol-based heat stabilizers, phosphorus-based heat stabilizers, amine-based heat stabilizers, metal salts of elements in Groups 3, 4, and 11 to 14 of the Periodic Table, and halides of alkali metals and alkaline earth metals.

(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-t-butyl-4-hydroxyphenylpropionamide), pentaerythrityl-tetrakis[3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate], N,N'-hexamethylenebis(3,5-di-t-butyl-4-hydroxy-hydrocinnamamide), triethylene glycol-bis[3-(3-t-butyl-5-methyl-4-hydroxyphenyl)propionate], and the like. onate], 3,9-bis{2-[3-(3-t-butyl-4-hydroxy-5-methylphenyl)propynyloxy]-1,1-dimethylethyl}-2,4,8,10-tetraoxaspiro[5,5]undecane, 3,5-di-t-butyl-4-hydroxybenzylphosphonate-diethyl ester, 1,3,5-trimethyl-2,4,6-tris(3,5-di-t-butyl-4-hydroxybenzyl)benzene, 1,3,5-tris(4-t-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.
In particular, from the viewpoint of improving heat aging resistance, N,N'-hexane-1,6-diylbis[3-(3,5-di-t-butyl-4-hydroxyphenylpropionamide)] is preferred as the hindered phenol compound.

When a phenol-based heat stabilizer is used, the content of the phenol-based heat stabilizer in the polyamide composition is preferably 0 mass % or more and 1 mass % or less, and more preferably 0.1 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-t-butylphenyl)phosphite, tris(2,4-di-t-butyl-5-methylphenyl)phosphite, sphite, tris(butoxyethyl)phosphite, 4,4'-butylidene-bis(3-methyl-6-t-butylphenyl-tetra-tridecyl)diphosphite, tetra(C12-C15 mixed alkyl)-4,4'-isopropylidene diphenyl diphosphite, 4,4'-isopropylidene bis(2-t-butylphenyl)-di(nonylphenyl)phosphite, tris(biphenyl)phosphite, tetra(tridecyl)-1,1,3-tris(2-methyl-5-t-butyl-4-hydroxyphenyl)butane diphosphite, tetra(tridecyl)-4,4'-butylidene bis(3-methyl-6-t-butylphenyl)diphosphite, tetra(C1- C15 mixed alkyl)-4,4'-isopropylidene diphenyl diphosphite, tris(mono, di mixed nonylphenyl)phosphite, 4,4'-isopropylidene bis(2-t-butylphenyl)-di(nonylphenyl)phosphite, 9,10-di-hydro-9-oxa-9-oxa-10-phosphaphenanthrene-10-oxide, tris(3,5-di-t-butyl-4-hydroxyphenyl)phosphite, hydrogenated-4,4'-isopropylidene diphenyl polyphosphite, bis(octylphenyl)-bis(4,4'-butylidene bis(3-methyl-6-t-butylphenyl))-1,6-hexanol diphosphite, hexatridecyl-1 , 1,3-tris(2-methyl-4-hydroxy-5-t-butylphenyl)diphosphite, tris(4,4'-isopropylidenebis(2-t-butylphenyl))phosphite, tris(1,3-stearoyloxyisopropyl)phosphite, 2,2-methylenebis(4,6-di-t-butylphenyl)octylphosphite, 2,2-methylenebis(3-methyl-4,6-di-t-butylphenyl)2-ethylhexylphosphite, tetrakis(2,4-di-t-butyl-5-methylphenyl)-4,4'-biphenylene diphosphite, and tetrakis(2,4-di-t-butylphenyl)-4,4'-biphenylene diphosphite.
These phosphorus-based heat stabilizers may be used alone or in combination of two or more.
Among these, from the viewpoint of further improving the heat aging resistance of the polyamide composition and reducing the amount of gas generation, the phosphorus-based heat stabilizer is preferably at least one selected from the group consisting of pentaerythritol-type phosphite compounds and tris(2,4-di-t-butylphenyl)phosphite.

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

When a phosphorus-based heat stabilizer is used, the content of the phosphorus-based heat stabilizer in the polyamide composition is preferably 0 mass % or more and 1 mass % or less, and more preferably 0.01 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-benzyl Oxy-2,2,6,6-tetramethylpiperidine, 4-phenoxy-2,2,6,6-tetramethylpiperidine, 4-(ethylcarbamoyloxy)-2,2,6,6-tetramethylpiperidine, 4-(cyclohexylcarbamoyloxy)-2,2,6,6-tetramethylpiperidine, 4-(phenylcarbamoyloxy)-2,2,6,6-tetramethylpiperidine, bis(2,2,6,6-tetramethyl-4-piperidyl)-carbonate, bis(2,2,6,6-tetramethyl-4-piperidyl)-oxalate, bis(2,2,6,6-tetramethyl-4-piperidyl)-malonate, bis(2,2,6,6-tetramethyl-4 -piperidyl)-sebacate, bis(2,2,6,6-tetramethyl-4-piperidyl)-adipate, bis(2,2,6,6-tetramethyl-4-piperidyl)-terephthalate, 1,2-bis(2,2,6,6-tetramethyl-4-piperidyloxy)-ethane, α,α'-bis(2,2,6,6-tetramethyl-4-piperidyloxy)-p-xylene, 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-tricarboxylate, tris(2,2,6,6-tetramethyl-4-piperidyl)-benzene-1,3,4-tricarboxylate, 1-[2-{3-(3,5-di-t-butyl-4-hydroxyphenyl)propionyloxy}butyl]-4-[3-(3,5-di-t-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 mass % or more and 1 mass % or less, and more preferably 0.01 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 halides, copper acetate, copper propionate, copper benzoate, copper adipate, copper terephthalate, copper isophthalate, copper salicylate, copper nicotinate, copper stearate, and copper complex salts in which copper is coordinated with a chelating agent.

Examples of copper halides include copper iodide, copper (I) bromide, copper (II) bromide, and copper (I) chloride.
Examples of the chelating agent include ethylenediamine and ethylenediaminetetraacetic acid.
These copper salts may be used alone or in combination of two or more.
Among them, the copper salt is preferably at least one selected from the group consisting of copper iodide, copper (I) bromide, copper (II) bromide, copper (I) chloride, and copper acetate, and more preferably at least one selected from the group consisting of copper iodide and copper acetate. When the above-mentioned preferred copper salts are used, a polyamide composition is obtained which is more excellent in heat aging resistance and can more effectively suppress metal corrosion of the screw and cylinder during extrusion (hereinafter, sometimes simply referred to as "metal corrosion").

When a copper salt is used as the heat stabilizer (F4), the content of the copper salt in the polyamide composition is preferably 0 mass% or more and 0.60 mass% or less, and more preferably 0.01 mass% or more and 0.40 mass% or less, based on the total mass of the polyamide (the aliphatic polyamide (A) and the semi-aromatic polyamide (B)).
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 0 parts by mass or more and 2,000 parts by mass or less, more preferably 10 parts by mass or more and 2,000 parts by mass or less, still more preferably 20 parts by mass or more and 1,500 parts by mass or less, and particularly preferably 50 parts by mass or more and 1,000 parts by mass or less, relative to ¹⁰⁶ parts by mass (1 million parts by mass) of the polyamide (the aliphatic polyamide (A) and the semi-aromatic polyamide (B)).

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

When alkali metal and alkaline earth metal halides are used, the content of the alkali metal and alkaline earth metal halides in the polyamide composition is preferably 0 parts by mass or more and 20 parts by mass or less, and more preferably 0.01 parts by mass or more and 10 parts by mass or less, per 100 parts by mass of polyamide ((A) aliphatic polyamide and (B) semi-aromatic polyamide).
When the content of alkali metal and alkaline earth metal halides is within the above range, the heat aging resistance of the polyamide composition is further improved, and copper precipitation and metal corrosion can be more effectively suppressed.

The components of the heat stabilizer (F4) explained above may be used alone or in combination of two or more.
Among these, as the heat stabilizer (F4), from the viewpoint of further improving the heat aging resistance of the polyamide composition, a mixture of a copper salt and a halide of an alkali metal and an alkaline earth metal is preferred.

The content ratio of the copper salt and the alkali metal and alkaline earth metal halides is preferably from 2/1 to 40/1, more preferably from 5/1 to 30/1, in terms of the molar ratio of halogen to copper (halogen/copper).
When the molar ratio of halogen to copper (halogen/copper) is within the above range, the heat aging resistance of the polyamide composition can be further improved.
In addition, when the molar ratio of halogen to copper (halogen/copper) is equal to or greater than the lower limit, copper precipitation and metal corrosion can be more effectively suppressed, whereas when the molar ratio of halogen to copper (halogen/copper) is equal to or less than the upper limit, corrosion of the screw of the molding machine and the like can be more effectively prevented without substantially impairing mechanical properties (toughness, etc.).

(Coloring Agent)
In the present embodiment, the method for coloring the resin composition is not particularly limited, and at least one colorant selected from known organic dyes and pigments and inorganic dyes and pigments can be used.

Examples of organic dyes and pigments include azo pigments such as azo lake pigments, benzimidazolone pigments, diarylide pigments, and condensed azo pigments; phthalocyanine pigments such as phthalocyanine blue and phthalocyanine green; isoindolinone pigments, quinophthalone pigments, quinacridone pigments, perylene pigments, anthraquinone pigments, perinone pigments, condensed polycyclic pigments such as dioxazine violet; azine pigments; and carbon black.

Examples of inorganic pigments include metal oxides other than iron oxide, such as titanium oxide, zinc oxide, and chromium oxide, and composite metal oxides such as titanium yellow, cobalt blue, and ultramarine.

The preferred amount of the colorant to be added is 10% by mass or less, more preferably 5% by mass or less, even more preferably 2% by mass or less, and particularly preferably 1% by mass or less, based on the total mass of the resin composition. By adding the colorant in an amount within the above range, a good balance between low dielectric constant, impact resistance, and mechanical properties can be maintained. In addition, molded products that have excellent moldability during injection molding and excellent surface appearance can be obtained.

<Method of 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 the aliphatic polyamide (A) with each of the components (B) to (E) and, if necessary, the component (F).
Examples of methods for mixing the above components (A) to (E) and, if necessary, the above component (F) include the following methods (1) and (2).
(1) The above components (A) to (E) and, if necessary, the above component (F) 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 the above components (A) to (E) and, if necessary, the above component (F) are mixed in advance using a single-screw or twin-screw extruder or the like and fed to a melt kneader, and then a mixture containing each of the components (A) to (B) and, if necessary, the component (C) is prepared, and the mixture is fed to the melt kneader and kneaded, and then, optionally, the component (E) is blended from a side feeder.

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

<Characteristics of polyamide composition>
[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., further preferably 110° C., and particularly preferably 115° 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 further 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 115°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 a higher flexural modulus at high temperatures. 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 product tends to have better impact resistance and surface appearance.
Examples of a method for controlling the tan δ peak temperature of the polyamide composition within the above range include a method of controlling the contents of (A) the aliphatic polyamide and (B) the semi-aromatic polyamide within the above range.

<Dielectric constant>
The "dielectric constant" (ε) is a measure of the behavior of a molecule when subjected to an electric field. The dielectric constant is related to the "relative permittivity" (εr) and the "vacuum permittivity" (ε0) by the equation ε = εr · ε0. The "relative permittivity" (εr) represents a material-dependent value and is the quotient of the "dielectric constant" (ε) and the "vacuum permittivity" (ε0). In addition to being a material property, the "relative permittivity" (εr) depends on the frequency and temperature of the electric field. The relative permittivity is preferably measured according to IEC 61189-2-721.

<Molded products>
In addition, the molded article of the present embodiment has a high surface gloss value. The surface gloss value of the molded article of the present embodiment is preferably 50 or more, more preferably 55 or more, and even more preferably 60 or more. Since the surface gloss value of the molded article is equal to or more than the above lower limit, the molded article of the present embodiment can be suitably used as various parts for automobiles, electrical and electronic products, industrial materials, industrial materials, daily necessities and household goods, etc.

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 is excellent in surface appearance, flexural modulus at high temperatures, impact resistance, and the like, and can be used for a variety of applications.
The molded article of the present embodiment can be suitably used in, for example, the automotive field, the electrical and electronic field, communication equipment, the mechanical and industrial field, the office equipment field, as well as daily necessities and household goods.

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.
Each of the components of the polyamide composition used in the examples and comparative examples will be described below.

<Components>
[(A) Aliphatic polyamide]
A-1: Polyamide 66 (manufactured by Asahi Kasei Corporation, Mw = 35,000, Mw/Mn = 2.0)
A-2: Polyamide 612 (manufactured by Asahi Kasei Corporation, Mw = 22,000, Mw / Mn = 2.0)

[(B) Semi-aromatic polyamide]
B-1: Polyamide 6I (manufactured by Asahi Kasei Corporation, Mw = 20,000, Mw / Mn = 2.0)
B-2: Polyamide 6I/6T (manufactured by EMS Co., Ltd., model number: G21, Mw = 27,000, Mw/Mn = 2.2, ratio of isophthalic acid units in dicarboxylic acid units is 70 mol%)

[(C) Amorphous Resin]
C-1: Polystyrene (PS) (manufactured by PS Japan Co., Ltd., product name: GPPS 685, glass transition temperature 105° C., Mw(C)=210,000, styrene unit ratio=100% by mass)
C-2: Polystyrene (PS) (manufactured by PS Japan Co., Ltd., product name: GPPS 680, glass transition temperature 105° C., Mw(C)=200,000, styrene unit ratio=100% by mass)
C-3: Acrylonitrile-styrene copolymer (AS) (manufactured by Asahi Kasei Corporation, product name: Stylac T8804, glass transition temperature 110°C, Mw(C) = 80,000, styrene unit ratio = 73% by mass)
C-4: Acrylonitrile-butadiene-styrene copolymer (ABS) (manufactured by Asahi Kasei Corporation, product name: Stylac 190, glass transition temperature 110°C, Mw(C) = 125,000, styrene unit ratio = 60% by mass)
C-5: High impact polystyrene (HIPS) (Petrochemicals Co., Ltd., product name: CT60, glass transition temperature 105°C, styrene unit ratio = 90% by mass)
The glass transition temperature of the amorphous resin (C) was measured by differential scanning calorimetry in accordance with JIS-K7121, raising the temperature at a rate of 20° C./min.

[(D) Polymer containing α,β-unsaturated dicarboxylic acid anhydride units]
D-1: Maleic anhydride modified polyphenylene ether (m-PPE)

[(E) Glass filler]
E-1: Glass fiber (GF) (manufactured by Nitto Boseki Co., Ltd., NE Glass CN 3J-256, relative dielectric constant at frequency of 1.0 GHz (bulk glass test piece of the same composition, length of about 50 mm, width of about 1.5 mm, measured using a network analyzer (N5230A, manufactured by Agilent Technologies) and a cavity resonator (Cavity Resonator CP series, manufactured by Kanto Electronics Application Development Co., Ltd.) under an environment of 23±2°C and relative humidity of 50±5%) is about 4.8, and dielectric loss tangent is about 0.0015)
E-2: Glass fiber (GF) (manufactured by Nippon Electric Glass Co., Ltd., ECS03T-275H, cross-sectional diameter 13 μm, fiber length 3 mm, relative dielectric constant at frequency 1.0 GHz (bulk glass test piece of the same composition, length about 50 mm, width about 1.5 mm, measured using a network analyzer (N5230A, manufactured by Agilent Technologies) and a cavity resonator (Cavity Resonator CP series, manufactured by Kanto Electronics Application Development Co., Ltd.) under an environment of 23 ± 2 ° C. and relative humidity 50 ± 5%) is about 6.8, and dielectric loss tangent is about 0.0035)

<Production of Resin>
The production methods of the aliphatic polyamide A-1 (polyamide 66), the semi-aromatic polyamide B-1 (polyamide 6I), and the polymer D-1 containing α,β-unsaturated dicarboxylic anhydride units (maleic anhydride-modified polyphenylene ether) are described in detail below. The aliphatic polyamide A-1, the semi-aromatic polyamide B-1, and the polymer D-1 containing α,β-unsaturated dicarboxylic anhydride units obtained by the production methods described below were dried in a nitrogen stream to adjust the moisture content to about 0.2 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 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 and formed into strands from the lower spinneret (nozzle), cooled with water, cut, and discharged in the form of pellets, which were then dried at 100° C. in a nitrogen atmosphere for 12 hours to obtain aliphatic polyamide A-1 (polyamide 66).

Synthesis Example 2 Synthesis of Aliphatic Polyamide A-2 (Polyamide 612) 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 dodecanediamine was dissolved in 1800 g of distilled water to prepare a homogeneous aqueous solution of raw material monomers. This aqueous solution was placed in an autoclave with an internal volume of 5.4 L and purged with nitrogen.
The mixture was concentrated by gradually releasing steam until the solution concentration reached 70% by mass while stirring at a temperature of 110 to 150°C. The internal temperature was then raised to 220°C. At this time, the autoclave was pressurized to 1.8 MPa. The mixture was allowed to react for 1 hour while gradually releasing steam to keep the pressure at 1.8 MPa until the internal temperature reached 245°C.
Next, the pressure was reduced over 1 hour and 30 minutes. After that, the inside of the autoclave was kept under a reduced pressure of 650 torr for 10 minutes by a vacuum device. At this time, the final internal temperature of the polymerization was 265°C.
Thereafter, the mixture was pressurized with nitrogen and formed into a strand from the lower spinneret (nozzle), water-cooled, cut, and discharged in the form of pellets, which were then dried at 100° C. in a nitrogen atmosphere for 12 hours to obtain aliphatic polyamide A-2 (polyamide 612).

Synthesis Example 3 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, as well as 1.5 mol % excess adipic acid and 0.5 mol % acetic acid relative to the total equimolar salt components, 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 110 ° C. or higher and 150 ° C. or lower. 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 and formed into strands from the lower spinneret (nozzle), cooled with water, cut, and discharged in the form of pellets, which were then dried at 100° C. in a nitrogen atmosphere for 12 hours to obtain semi-aromatic polyamide B-1 (polyamide 6I).

Synthesis Example 4 Synthesis of Polymer D-1 (Maleic Anhydride Modified Polyphenylene Ether) Containing α,β-Unsaturated Dicarboxylic Anhydride Units Poly(2,6-dimethyl-1,4-phenylene ether) (hereinafter, may be abbreviated as "polyphenylene ether") having a reduced viscosity of 0.52 (0.5 g/dL chloroform solution, measured at 30°C) obtained by oxidative polymerization of 2,6-dimethylphenol and 1.0 part by mass of maleic anhydride as a compatibilizer were used. A twin-screw extruder (Werner & Pfleiderer, ZSK-40) having one supply port on the upstream side (hereinafter sometimes abbreviated as "top-F") and two supply ports on the central part of the extruder and the downstream side near the die (hereinafter sometimes abbreviated as "side-1" for the central part of the extruder and "side-2" for the downstream side near the die) was in a blocked state with the side-1 and side-2, and the polyphenylene ether and maleic anhydride were dry-blended and fed from top-F under the conditions of a cylinder set temperature of 320 ° C., a screw rotation of 300 rpm, and a discharge rate of 20.15 kg / hr. The mixture was then melt-kneaded and taken out in the form of a strand, and cooled in a strand bath (water tank). The mixture was then granulated with a cutter to obtain pellets of maleic anhydride-modified polyphenylene ether.

<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.

[Production of molded products]
The molded articles used for each physical property and each evaluation were manufactured by the following methods.
The equipment used was "NEX-50III" or "NEX-50IV" manufactured by Nissei Plastic Industrial Co., Ltd. The cylinder temperature was set to 290°C, the mold temperature to 100°C, and each polyamide composition was molded up to 100 shots under injection molding conditions of 10 seconds injection and 10 seconds cooling, to obtain molded products (ISO test pieces).

[Physical Property 1] tan δ Peak Temperature Using the molded article obtained in the above "Production of molded article", measurement was performed under the following conditions using a dynamic viscoelasticity evaluation device (GABO Corporation, EPLEXOR500N).

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

The ratio of the loss modulus E2 to the storage modulus E1 (E2/E1) was defined as tan δ, and the highest temperature was defined as the tan δ peak temperature.

[Physical property 2] Weight average molecular weight, number average molecular weight and molecular weight distribution of polyamide composition The weight average molecular weight (Mw) and number average molecular weight (Mn) of the polyamide obtained in the synthesis example and the polyamide compositions obtained in the examples and comparative examples were measured by GPC under the following measurement conditions. The molecular weight distribution was calculated using the obtained Mw and Mn.

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

[Evaluation 1] Moldability and appearance (1) Evaluation of moldability When releasing the molded product during molding in the above "Production of molded product", the percentage of the molded product that adhered to the mold was calculated out of 100 shots. Then, the moldability was evaluated according to the following evaluation criteria.

(Evaluation criteria)
A: 10% or less B: More than 10% but less than 20% C: More than 20% but less than 50% D: More than 50%

(2) Evaluation of Surface Gloss Regarding the appearance of the molded article obtained by the above "Production of Molded Article", the 60 degree gloss of the gripped part of the molded article was measured using a gloss meter (IG320 manufactured by HORIBA) in accordance with JIS-K7150. From the measured surface gloss value, the appearance was evaluated according to the following evaluation criteria.

(Evaluation criteria)
A: 60 or more B: 55 or more but less than 60 C: 50 or more but less than 55 D: Less than 50

(3) Evaluation of Surface Appearance The appearance of the molded product obtained by the above "Production of Molded Product" was evaluated by comprehensively judging the surface gloss, sink marks, pockmarks, silver spots, etc. on the surface of the molded product.

(Evaluation criteria)
A: Excellent B: Good C: Fair D: Poor

[Evaluation 2] Flexural modulus at 23°C Using the ISO test pieces obtained in the above "Production of molded products" from 20 to 30 shots, the flexural modulus was measured in accordance with ISO 178. The measured value was the average value of n = 6.

[Evaluation 3] Charpy impact strength Using the ISO test pieces obtained in the above "Production of molded products" from 20 to 30 shots, the Charpy impact strength was measured in accordance with ISO 179. The measured value was the average value of n = 6.

[Evaluation 4] Dielectric properties The molded product obtained in the above "Production of molded product" was cut to prepare a test specimen.
Using the above test pieces, the dielectric constant (Dk) and dielectric loss tangent (Df) at 2.5 GHz were measured by a cavity resonance method.
The measurement devices used were a network analyzer: 10 MHz to 43.5 GHz PNA network analyzer N5224B, a 2.5 GHz resonator: 2.5 GHz Split Post Dielectric Resonator N1501AE03, and a 10 GHz resonator: 10 GHz Split Post Dielectric Resonator N1501AE10.

<Production of polyamide composition>
[Examples 1 to 11, Comparative Examples 1 to 9]
(Polyamide compositions PA-a1 to PA-a11 and PA-b1 to PA-b9)
A twin-screw extruder (manufactured by Coperion (Germany), ZSK-26MC) with an L/D (length of the cylinder of the extruder/cylinder diameter of the extruder) = 48 (number of barrels 12), having an upstream supply port on the first barrel from the upstream side of the extruder, a downstream supply port on the eighth barrel, and a vacuum devolatilization port on the eleventh barrel, was used to supply (A) aliphatic polyamide, (B) semi-aromatic polyamide, (C) amorphous resin, and (D) a polymer containing α,β-unsaturated dicarboxylic anhydride units from the top feed port provided at the most upstream part of the extruder. In addition, (E) glass filler was supplied from the side feed port on the downstream side of the extruder (in a state where the resin supplied from the top feed port is fully melted), and melt-kneaded by reducing the pressure from the vacuum devolatilization port. Next, the molten kneaded product extruded from the die head was cooled in a strand shape and pelletized to obtain pellets of a polyamide composition.
The resulting polyamide composition was used to produce a molded article by the above-mentioned method, and various physical properties were evaluated. The evaluation results are shown in Table 1 below.

[Example 1] Production of polyamide composition PA-a1 According to the above production method, the blending amounts were (A) aliphatic polyamide A-1: 24.9 mass%, (B) semi-aromatic polyamide B-1: 10.7 mass%, (C) amorphous resin C-1: 21.9 mass%, (D) polymer D-1 containing α,β-unsaturated dicarboxylic anhydride unit: 1.0 mass%, and (E) glass filler E-1: 40 mass%. Various physical properties and evaluations were performed using the obtained pellets of polyamide composition PA-a1. The evaluation results are shown in Table 1 below.

[Example 2] Production of polyamide composition PA-a2 Pellets of polyamide composition PA-a2 were obtained using the same method as in Example 1, except that the blending amounts were changed to (A) aliphatic polyamide A-1: 20.6 mass%, (B) semi-aromatic polyamide B-1: 8.7 mass%, (C) amorphous resin C-1: 18.2 mass%, and (E) glass filler E-1: 50 mass%. Various physical properties and evaluations were performed using the obtained pellets of polyamide composition PA-a2. The evaluation results are shown in Table 1 below.

[Example 3] Production of polyamide composition PA-a3 Pellets of polyamide composition PA-a3 were obtained using the same method as in Example 1, except that the blending amounts were changed to (A) aliphatic polyamide A-1: 16.0 mass%, (B) semi-aromatic polyamide B-1: 7.0 mass%, (C) amorphous resin C-1: 14.5 mass%, and (E) glass filler E-1: 60 mass%. Various physical properties and evaluations were performed using the obtained pellets of polyamide composition PA-a3. The evaluation results are shown in Table 1 below.

[Example 4] Production of polyamide composition PA-a4 Pellets of polyamide composition PA-a4 were obtained using the same method as in Example 1, except that the blending amounts were changed to (A) aliphatic polyamide A-1: 21.6 mass%, (B) semi-aromatic polyamide B-1: 9.5 mass%, and (C) amorphous resin C-1: 26.4 mass%. Various physical properties and evaluations were performed using the obtained pellets of polyamide composition PA-a4. The evaluation results are shown in Table 1 below.

[Example 5] Production of polyamide composition PA-a5 Pellets of polyamide composition PA-a5 were obtained using the same method as in Example 1, except that the blending amounts were changed to (A) aliphatic polyamide A-1: 32.0 mass%, (B) semi-aromatic polyamide B-1: 13.5 mass%, and (C) amorphous resin C-1: 12.0 mass%. Various physical properties and evaluations were performed using the obtained pellets of polyamide composition PA-a5. The evaluation results are shown in Table 1 below.

[Example 6] Production of polyamide composition PA-a6 Pellets of polyamide composition PA-a6 were obtained using the same method as in Example 1, except that the blending amounts were changed to (A) aliphatic polyamide A-1: 17.8 mass%, (B) semi-aromatic polyamide B-1: 17.8 mass%, and (C) amorphous resin C-1: 21.9 mass%. Various physical properties and evaluations were performed using the obtained pellets of polyamide composition PA-a6. The evaluation results are shown in Table 1 below.

[Example 7] Production of polyamide composition PA-a7 Pellets of polyamide composition PA-a7 were obtained using the same method as in Example 1, except that the blending amounts were changed to (A) aliphatic polyamide A-1: 22.7 mass%, (B) semi-aromatic polyamide B-1: 9.8 mass%, (C) amorphous resin C-1: 21.0 mass%, and (D) polymer D-1 containing α,β-unsaturated dicarboxylic anhydride units: 5.0 mass%. Various physical properties and evaluations were performed using the obtained pellets of polyamide composition PA-a7. The evaluation results are shown in Table 1 below.

[Example 8] Production of polyamide composition PA-a8 Pellets of polyamide composition PA-a8 were obtained using the same method as in Example 1, except that 21.9 mass% of (C) amorphous resin C-3 was used instead of (C) amorphous resin C-1. Various physical properties and evaluations were performed using the obtained pellets of polyamide composition PA-a8. The evaluation results are shown in Table 1 below.

[Example 9] Production of polyamide composition PA-a9 Pellets of polyamide composition PA-a9 were obtained in the same manner as in Example 1, except that 21.9 mass% of (C) amorphous resin C-4 was used instead of (C) amorphous resin C-1. Various physical properties and evaluations were performed using the obtained pellets of polyamide composition PA-a9. The evaluation results are shown in Table 1 below.

[Example 10] Production of polyamide composition PA-a10 Pellets of polyamide composition PA-a10 were obtained using the same method as in Example 1, except that 10.7 mass% of (B) semi-aromatic polyamide B-2 was used instead of (B) semi-aromatic polyamide B-1. Various physical properties and evaluations were performed using the obtained pellets of polyamide composition PA-a10. The evaluation results are shown in Table 1 below.

[Example 11] Production of polyamide composition PA-a11 Pellets of polyamide composition PA-a11 were obtained using the same method as in Example 1, except that 21.9 mass% of (C) amorphous resin C-2 was used instead of (C) amorphous resin C-1. Various physical properties and evaluations were performed using the obtained pellets of polyamide composition PA-a11. The evaluation results are shown in Table 1 below.

[Example 12] Preparation of polyamide composition PA-a12 Pellets of polyamide composition PA-a12 were obtained in the same manner as in Example 1, except that 24.9 mass% of (A) aliphatic polyamide resin A-2 was used instead of (A) aliphatic polyamide resin A-1. Various physical properties and evaluations were performed using the obtained pellets of polyamide composition PA-a12. The evaluation results are shown in Table 2 below.

[Example 13] Preparation of polyamide composition PA-a13 Pellets of polyamide composition PA-a13 were obtained in the same manner as in Example 1, except that 21.9 mass% of (C) amorphous resin C-5 was used instead of (C) amorphous resin C-1. Various physical properties and evaluations were performed using the obtained pellets of polyamide composition PA-a13. The evaluation results are shown in Table 2 below.

Comparative Example 1: Production of polyamide composition PA-b1 Pellets of polyamide composition PA-b1 were obtained using the same method as in Example 1, except that the blending amounts were changed to (A) aliphatic polyamide A-1: 40.0 mass%, (B) semi-aromatic polyamide B-1: 18.5 mass%, (C) amorphous resin C-1: 0.0 mass%, and (D) polymer D-1 containing α,β-unsaturated dicarboxylic anhydride units: 0.0 mass%. Various physical properties and evaluations were performed using the obtained pellets of polyamide composition PA-b1. The evaluation results are shown in Table 2 below.

[Comparative Example 2] Preparation of polyamide composition PA-b2 Pellets of polyamide composition PA-b2 were obtained using the same method as in Example 1, except that the blending amounts were changed to (A) aliphatic polyamide A-1: 38.0% by mass, (B) semi-aromatic polyamide B-1: 15.5% by mass, (C) amorphous resin C-1: 5.0% by mass, (D) polymer D-1 containing α,β-unsaturated dicarboxylic anhydride units: 0.0% by mass, and (E) filler E-1: 60% by mass. Various physical properties and evaluations were performed using the obtained pellets of polyamide composition PA-b2. The evaluation results are shown in Table 2 below.

Comparative Example 3: Production of polyamide composition PA-b3 Pellets of polyamide composition PA-b3 were obtained using the same method as in Example 1, except that the blending amounts were changed to (A) aliphatic polyamide A-1: 25.5 mass%, (B) semi-aromatic polyamide B-1: 10.6 mass%, (C) amorphous resin C-1: 22.4 mass%, and (D) polymer D-1 containing α,β-unsaturated dicarboxylic anhydride units: 0.0 mass%. Various physical properties and evaluations were performed using the obtained pellets of polyamide composition PA-b3. The evaluation results are shown in Table 2 below.

Comparative Example 4: Production of polyamide composition PA-b4 Pellets of polyamide composition PA-b4 were obtained using the same method as in Example 1, except that the blending amounts were changed to (A) aliphatic polyamide A-1: 35.6 mass % and (B) semi-aromatic polyamide B-1: 0.0 mass %. Various physical properties and evaluations were performed using the obtained pellets of polyamide composition PA-b4. The evaluation results are shown in Table 2 below.

Comparative Example 5: Production of polyamide composition PA-b5 Pellets of polyamide composition PA-b5 were obtained using the same method as in Example 1, except that the blending amounts were changed to (A) aliphatic polyamide A-1: 12.8 mass%, and (B) semi-aromatic polyamide B-1: 22.8 mass%. Various physical properties and evaluations were performed using the obtained pellets of polyamide composition PA-b5. The evaluation results are shown in Table 2 below.

[Comparative Example 6] Production of polyamide composition PA-b6 Pellets of polyamide composition PA-b6 were obtained using the same method as in Example 1, except that the blending amounts were changed to (A) aliphatic polyamide A-1: 19.5 mass%, (B) semi-aromatic polyamide B-1: 8.0 mass%, and (C) amorphous resin C-1: 33.0 mass%. Various physical properties and evaluations were performed using the obtained pellets of polyamide composition PA-b6. The evaluation results are shown in Table 2 below.

Comparative Example 7: Preparation of polyamide composition PA-b7 Pellets of polyamide composition PA-b7 were obtained in the same manner as in Example 1, except that 40.0 mass% of (E) glass filler E-2 was used instead of (E) glass filler E-1. Various physical properties and evaluations were performed using the obtained pellets of polyamide composition PA-b7. The evaluation results are shown in Table 2 below.

As seen from Tables 1 and 2, the molded articles obtained from polyamide compositions PA-a1 to PA-a11 (Examples 1 to 11), which are polyamide compositions containing (A) an aliphatic polyamide, (B) a semi-aromatic polyamide, (C) an amorphous resin, and (D) a polymer containing an α,β-unsaturated dicarboxylic acid anhydride as a structural unit, were excellent in dielectric properties, surface appearance, tensile strength, flexural modulus, and Charpy impact strength.
In addition, in the molded articles obtained from the polyamide compositions PA-a1 to PA-a3 (Examples 1 to 3) containing different amounts of filler, the flexural modulus and Charpy impact strength tended to be better as the amount of filler increased.
In addition, in the molded articles obtained from the polyamide compositions PA-a1, PA-a4, and PA-a5 (Examples 1, 4, and 5) containing different amounts of the amorphous resin (C), the relative dielectric constant and dielectric tangent of the resin composition tended to decrease with an increase in the amount of the amorphous resin (C).

In contrast, the resin composition obtained from the polyamide composition PA-b1 (Comparative Example 1), which does not contain (C) the amorphous resin and (D) a polymer containing an α,β-unsaturated dicarboxylic acid anhydride as a structural unit, had insufficient dielectric properties, and the moldability and surface appearance of the molded product were unsatisfactory.
In addition, the molded articles obtained from the polyamide compositions PA-b2 and PA-b3 (Comparative Examples 2 and 3), which contained the amorphous resin (C) but did not contain the polymer containing an α,β-unsaturated dicarboxylic acid anhydride as a constituent unit (D), had poor compatibility between the polyamide and the amorphous resin (C), and were insufficient in moldability, surface appearance of the molded article, and Charpy impact strength.
In addition, the resin composition obtained from polyamide composition PA-b4 (Comparative Example 4) not containing a semi-aromatic polyamide as a constituent unit (B) had an insufficient surface appearance of the molded product.
In addition, the polyamide compositions PA-b5 and PA-b6 (Comparative Examples 5 and 6), in which the blending amount of (B) semi-aromatic polyamide or the blending amount of (C) amorphous resin was outside the range of this embodiment, had poor moldability during injection molding, and the molded product had insufficient surface appearance and mechanical strength.
In addition, in the polyamide composition PA-b7 (Comparative Example 7) in which the relative dielectric constant of the (E) glass filler was outside the range of this embodiment, the dielectric properties of the polyamide composition were insufficient.

From the above, it has been confirmed that the polyamide composition of this embodiment can produce molded products with good dielectric properties, moldability, appearance, tensile strength, flexural modulus, and Charpy impact value.

The polyamide composition of this embodiment has a low dielectric constant and is capable of forming molded articles that have good mechanical rigidity and strength, moldability, and excellent surface appearance while maintaining good impact resistance, and it is possible to form molded articles by molding the polyamide composition. The molded articles of this embodiment can be suitably used in, for example, the automotive field, the electrical and electronic field, the communication equipment, the mechanical and industrial field, the office equipment field, and daily necessities and household goods, etc.

Claims (18)

(A) an aliphatic polyamide;
(B) a semi-aromatic polyamide containing dicarboxylic acid units and diamine units;
(C) an amorphous resin (excluding polyamides) having a glass transition temperature of 80° C. or more and 250° C. or less when heated at a rate of 20° C./min in differential scanning calorimetry according to JIS-K7121;
(D) a polymer containing an α,β-unsaturated dicarboxylic acid anhydride as a structural unit;
(E) at least one glass filler,
the content of the semi-aromatic polyamide (B) relative to the total content of the aliphatic polyamide (A) and the semi-aromatic polyamide (B) [(B)/((A)+(B))] is 5% by mass or more and 60% by mass or less;
a content of the amorphous resin (C) relative to a total content of the aliphatic polyamide (A), the semi-aromatic polyamide (B), the amorphous resin (C), and the α,β-unsaturated dicarboxylic acid anhydride (D) [(C)/((A)+(B)+(C)+(D))] is 5% by mass or more and 50% by mass or less;
The (E) glass filler has a relative dielectric constant of 6.0 or less at a frequency of 1 GHz.
Polyamide composition. The polyamide composition according to claim 1, wherein the aliphatic polyamide (A) contains aliphatic dicarboxylic acid units having 4 to 10 carbon atoms and aliphatic diamine units having 4 to 10 carbon atoms. The polyamide composition according to claim 1 or 2, wherein the aliphatic polyamide (A) is polyamide 66. The polyamide composition according to claim 1 or 2, wherein the (B) semi-aromatic polyamide contains 50 mol % or more of isophthalic acid units out of all dicarboxylic acid units constituting the (B) semi-aromatic polyamide, and contains, as the diamine units, diamine units having 4 to 10 carbon atoms. The polyamide composition according to claim 4, wherein the semi-aromatic polyamide (B) contains 80 mol % or more of isophthalic acid units among all dicarboxylic acid units constituting the semi-aromatic polyamide (B). The polyamide composition according to claim 5, wherein the semi-aromatic polyamide (B) contains 100 mol % isophthalic acid units out of all dicarboxylic acid units constituting the semi-aromatic polyamide (B). The polyamide composition according to claim 5, wherein the semi-aromatic polyamide (B) is polyamide 6I. The polyamide composition according to claim 1 or 2, wherein the ratio (C/N) of the number of carbon atoms C other than carbon atoms forming amide bonds to the number of nitrogen atoms N in all polyamides constituting the polyamide composition is 5.0 or more and less than 6.0. The polyamide composition according to claim 1 or 2, wherein the content of the (C) amorphous resin relative to the total content of the (A) aliphatic polyamide, the (B) semi-aromatic polyamide, the (C) amorphous resin, and the (D) α,β-unsaturated dicarboxylic anhydride [(C)/((A)+(B)+(C)+(D)]] is 20% by mass or more and 50% by mass or less. The polyamide composition according to claim 1 or 2, wherein the (C) amorphous resin is a polystyrene-based resin. The polyamide composition according to claim 10, wherein the proportion of olefin components contained in the polystyrene resin is 5 mass% or less. The polyamide composition according to claim 10, wherein the weight average molecular weight Mw of the polystyrene resin is 200,500 or more. The polyamide composition according to claim 1 or 2, wherein the content of the polymer (D) containing an α,β-unsaturated dicarboxylic anhydride as a structural unit is 1% by mass or more and 8% by mass or less with respect to the total mass of the polyamide composition. The polyamide composition according to claim 1 or 2, wherein the polymer (D) containing an α,β-unsaturated dicarboxylic acid anhydride as a constituent unit is a maleic anhydride-modified polyphenylene ether. The polyamide composition according to claim 1 or 2, wherein the (E) reinforcing filler is glass fiber, and the relative dielectric constant (Dk) of the glass fiber at a frequency of 1.0 GHz is 5.0 or less. The polyamide composition according to claim 1 or 2, wherein the (E) reinforcing filler is glass fiber, and the content of the glass fiber is 40% by mass or more and 60% by mass or less with respect to the total mass of the polyamide composition. The polyamide composition according to claim 1 or 2, containing additives other than (A) to (E) in an amount of 5 mass% or less based on the total mass of the polyamide composition. A molded article comprising the polyamide composition according to claim 1 or 2.