Polyamine composition

Abstract

A polyamide composition is provided, which provides a polyamide composition with high formability, excellent heat resistance and chemical resistance, comprising a polyamide (A) including a diamine unit (X) and a dicarboxylic acid unit (Y), and an organic heat stabilizer (B). The diamine unit (X) comprises 0.1 mol% or more and less than 36 mol% of a diamine unit (X1), wherein the diamine unit (X1) has 6 to 10 carbon atoms and is a structural unit derived from an aliphatic diamine, wherein the aliphatic diamine is such that when any one of the amino groups is bonded to a carbon atom at position 1, an alkyl group with 2 or 3 carbon atoms is bonded to the carbon atom at position 2.

Description

Polyamine composition This invention relates to a polyamide composition comprising polyamide and an organic heat stabilizer, wherein the polyamide contains specific diamine units having branched chains and dicarboxylic acid units. Crystalline polyamides, such as Nylon 6 and Nylon 66, are widely used in industrial parts due to their excellent heat resistance, mechanical properties, and formability. For example, in automotive applications, from the perspective of lightweighting and design freedom, the resinification of metal parts is underway, and crystalline polyamides with these excellent properties are being used extensively. However, from the perspective of improving fuel efficiency and complying with environmental regulations, the performance requirements for plastic materials are becoming increasingly stringent. Materials with superior heat resistance and chemical resistance are required. Furthermore, from the perspective of reducing manufacturing costs, materials with short melting and solidification times are needed; in other words, materials with high crystallization rates are required. High crystallization rates improve formability, reducing the time required to form a part and increasing production efficiency. Therefore, materials with high formability, as well as good heat resistance, chemical resistance, and other properties, are required. Patent Document 1 discloses a polyamide composition comprising polyamide and titanium dioxide particles, wherein the main chain of the polyamide is a diamine comprising at least 50 mol% of a branched diamine and a dicarboxylic acid comprising at least 50 mol% of an aliphatic dicarboxylic acid. Patent Document 1 states that the aforementioned polyamide composition exhibits excellent flowability, toughness, heat resistance, colorfastness, and processability. Furthermore, Patent Document 2 discloses a method for manufacturing a polyamide composition comprising structural units derived from diamines having methyl or ethyl branches. [Prior Art Documents] [Patent Documents] Patent Document 1: Japanese Patent Application Publication No. 2011-80055; Patent Document 2: Japanese Patent Publication No. 2017-517594 [The problem the invention aims to solve] In Patent Documents 1 and 2, examples of substituents branching from the main chain of a structural unit derived from a diamine forming polyamide include methyl, ethyl, and n-propyl groups. However, these documents specifically show only diamines with a methyl group as a branch chain. Neither document specifically discloses a polyamide containing structural units derived from a branched diamine having a substituent longer than the methyl group, in other words, having a substituent with more carbon atoms than the methyl group as a branch chain. Furthermore, neither document discloses any attempt to balance the formability and other properties of polyamide compositions by using polyamides with this structure. Therefore, the objective of this invention is to provide a polyamide composition with high formability, excellent heat resistance, and excellent chemical resistance. [Means for solving the objective] In order to solve the above-mentioned problems, in-depth research was conducted, and as a result, the inventors came up with the following invention, which solves the problems. That is, the present invention is as follows. [1] A polyamide composition comprising a polyamide (A) including a diamine unit (X) and a dicarboxylic acid unit, and an organic heat stabilizer (B), wherein the diamine unit (X) comprises 0.1 mol% or more and less than 36 mol% of a diamine unit (X1), wherein the diamine unit (X1) has 6 to 10 carbon atoms and is a structural unit derived from an aliphatic diamine, wherein the aliphatic diamine is such that when any one of the amino groups is bonded to a carbon atom at position 1, an alkyl group with 2 or 3 carbon atoms is bonded to a carbon atom at position 2. [2] The polyamide composition described above [1] wherein the diamine unit (X1) is a structural unit derived from the aforementioned aliphatic diamine with 9 carbon atoms. [3] The polyamide composition as described in [1] or [2] above, wherein the aforementioned diamine unit (X1) is derived from at least one structural unit selected from the group consisting of 2-ethyl-1,7-heptanediamine and 2-propyl-1,6-hexanediamine. [4] The polyamide composition as described in any one of [1] to [3] above, wherein the aforementioned diamine unit (X) comprises 1 to 10 moles of the aforementioned diamine unit (X1). [5] The polyamide composition described in any of [1] to [4] above, wherein the aforementioned diamine unit (X) further comprises a diamine unit (X2), the diamine unit (X2) being a diamine unit other than the aforementioned diamine unit (X1), and the aforementioned diamine unit (X2) being derived from at least one structural unit selected from the group consisting of linear aliphatic diamines, branched aliphatic diamines other than the aforementioned aliphatic diamines constituting the aforementioned diamine unit (X), alicyclic diamines, and aromatic diamines. [6] The polyamide composition described in [5] above, wherein the aforementioned diamine unit (X2) is derived from at least one structural unit selected from the group consisting of linear aliphatic diamines and branched aliphatic diamines with methyl branches. [7] The polyamide composition described in [5] or [6] above, wherein the aforementioned diamine unit (X2) is derived from a structural unit of a diamine having 6 to 10 carbon atoms. [8] In any of the polyamide compositions described in [5] to [7] above, the aforementioned diamine unit (X2) is derived from at least one structural unit selected from the group consisting of 1,6-hexanediamine, 1,9-nonanediamine, 1,10-decanediamine, 2-methyl-1,5-pentanediamine, and 2-methyl-1,8-octanediamine. [9] In any of the polyamide compositions described in [1] to [8] above, the aforementioned dicarboxylic acid unit (Y) comprises a structural unit derived from at least one structural unit selected from the group consisting of aliphatic dicarboxylic acids, aromatic dicarboxylic acids, and alicyclic dicarboxylic acids.

[10] In any of the polyamide compositions described in [1] to [9] above, the aforementioned dicarboxylic acid unit (Y) comprises a structural unit derived from at least one structural unit selected from the group consisting of terephthalic acid, cyclohexanedicarboxylic acid, and naphthalenedicarboxylic acid.

[11] The polyamide composition described in any one of [1] to

[10] above, wherein, relative to 100 parts by mass of the aforementioned polyamide (A), it contains 0.05 to 5 parts by mass of the aforementioned organic heat stabilizer (B).

[12] The polyamide composition described in any one of [1] to

[11] above, wherein the aforementioned organic heat stabilizer (B) is selected from at least one of the group consisting of phenolic heat stabilizers (B1), phosphorus heat stabilizers (B2), sulfur heat stabilizers (B3), and amine heat stabilizers (B4).

[13] A molded article made of the polyamide composition described in any one of [1] to

[12] above.

[14] The molded article described in

[13] above is a film. [Effects of the Invention]. According to the present invention, a polyamide composition with high formability, excellent heat resistance and chemical resistance can be provided. [The form in which the invention is carried out] The following description is based on an example of an embodiment of the present invention (hereinafter sometimes referred to as "this embodiment"). However, the embodiment shown below is an example used to embody the technical concept of the present invention, and the present invention is not limited to the following description. Furthermore, in this specification, preferred forms of the embodiment are shown, but combinations of two or more preferred forms are also preferred forms. Regarding matters expressed in numerical ranges, when there are several numerical ranges, the lower limit and upper limit values ​​can be selectively combined as preferred forms. In this specification, when a numerical range of "XX to YY" is mentioned, it means "XX or more and YY or less". Furthermore, in this specification, "~ unit" (where "~" represents a monomer) means "a structural unit derived from ~", for example, "dicarboxylic acid unit" means "a structural unit derived from dicarboxylic acid", and "diamine unit" means "a structural unit derived from diamine". [1] Polyamide Composition The polyamide composition of this embodiment contains a polyamide (A) comprising a diamine unit (X) and a dicarboxylic acid unit (Y). Then, the diamine unit (X) comprises 0.1 mol% or more and less than 36 mol% of a diamine unit (X1), which is a structural unit with 6 to 10 carbon atoms and is derived from an aliphatic diamine, wherein the aliphatic diamine has an alkyl group with 2 or 3 carbon atoms bonded to the carbon atom at the 2 position when any one of the amino groups is set to the 1 position. The above-mentioned polyamide composition has high formability and also exhibits excellent heat resistance and chemical resistance. Generally, if a polymer backbone contains components with large substituents, such as branched chains, the molecular chains become difficult to arrange regularly, thus the polymer tends to exhibit a low crystallization rate. However, in the polyamide composition of this embodiment, by using polyamide (A) containing a specific amount of diamine components with alkyl groups having 2 or 3 carbon atoms, such as ethyl or propyl, as branched chains, a surprisingly high crystallization rate is observed. Furthermore, generally, if polyamides have large substituents, such as branched chains, it becomes difficult to obtain a crystalline structure, tending to result in a lower melting point. However, the polyamide (A) contained in the polyamide composition of this embodiment, even with relatively large substituents such as ethyl or propyl having 2 or 3 carbon atoms as branched chains, shows little decrease in melting point. Moreover, the glass transition temperature is a property that increases with the lower the molecular mobility of the amorphous portion. Therefore, if a component with highly mobile molecules, such as branched chains, is included, the glass transition temperature generally tends to be lower. However, the polyamide (A) contained in the polyamide composition of this embodiment unexpectedly exhibits only a slight decrease in glass transition temperature. One reason for the above-mentioned properties of polyamide (A) is believed to be that the number of carbon atoms in the branched chains, the position of the branched chains, and the amount of branched chains in the diamine units (X) contained in polyamide (A) both inhibit a significant reduction in heat resistance and chemical resistance and affect the increase in crystallization rate. However, the detailed reasons are unclear. In addition to containing polyamide (A) with the above-mentioned properties, the polyamide composition of this embodiment, by containing an organic heat stabilizer (B), improves heat resistance and chemical resistance without significantly affecting the crystallization rate, and is believed to exhibit high formability and excellent heat resistance and chemical resistance. [Polyamide (A)] The polyamide (A) contained in the above-mentioned polyamide composition comprises a diamine unit (X) and a dicarboxylic acid unit (Y). The composition of polyamide (A) will be described below. <Diamine Unit (X)> The diamine unit (X) comprises a diamine unit (X1), which has 6 to 10 carbon atoms and is a structural unit derived from an aliphatic diamine. This aliphatic diamine is characterized by having an alkyl group (2 or 3 carbon atoms) bonded to the carbon atom at position 1 of any one of its amino groups. (Diamine Unit (X1)) The diamine unit (X1) is a structural unit derived from an aliphatic diamine having the following structure: In this aliphatic diamine, conceived as a straight aliphatic chain with the carbon atoms bonded to the two amino groups as the two end carbon atoms, the hydrogen atom at position 2 of the carbon atom adjacent to the carbon atom bonded to any one of its amino groups is replaced by an alkyl group (2 or 3 carbon atoms). Hereinafter, the structural unit derived from an aliphatic diamine having the structure where the hydrogen atom at position 2 is replaced by an alkyl group (2 or 3 carbon atoms) is also referred to as a "branched aliphatic diamine unit". The branched aliphatic diamine unit constituting the diamine unit (X1) preferably has 8 to 10 carbon atoms, and more preferably 9. If the number of carbon atoms is within the above range, the polymerization reaction between the dicarboxylic acid and the diamine proceeds well, and the physical properties of the polyamide (A) are more easily improved. In the branched aliphatic diamine unit constituting the diamine unit (X1), the alkyl group with 2 or 3 carbon atoms bonded to the carbon atom at the 2-position is preferably selected from at least one of the group consisting of ethyl, propyl, and isopropyl, and more preferably from at least one of the group consisting of ethyl and propyl. If the alkyl group bonded to the carbon atom at the 2-position has 2 or 3 carbon atoms, the crystallization rate is increased, and it becomes easier to suppress the decrease in heat resistance. The branched aliphatic diamine used to form the diamine unit (X1) may have branched chains such as methyl groups (referred to as "other branched chains") on the carbon atoms other than the 2-position, provided that the effects of the present invention are not impaired. The number of other branched chains is preferably one or less, and the diamine unit (X1) is further preferably free of other branched chains. Examples of diamine units (X1) include structural units derived from 2-ethyl-1,4-butanediamine, 2-ethyl-1,5-pentanediamine, 2-ethyl-1,6-hexanediamine, 2-ethyl-1,7-heptanediamine, 2-ethyl-1,8-octanediamine, 2-propyl-1,5-pentanediamine, 2-propyl-1,6-hexanediamine, 2-propyl-1,7-heptanediamine, and 2,4-diethyl-1,6-hexanediamine. These structural units may include only one type or more types. From the viewpoint of expecting a more superior crystallization rate and excellent hydrolysis resistance in the obtained molded article, the diamine unit (X1) is preferably derived from at least one structural unit selected from the group consisting of 2-ethyl-1,7-heptanediamine and 2-propyl-1,6-hexanediamine. The diamine unit (X) contains 0.1 mol% or more and less than 36 mol% of diamine unit (X1). If the content of diamine unit (X1) is 0.1 mol% or more, the crystallization rate can be sufficiently increased; if it is less than 36 mol%, the heat resistance will not be excessively reduced. In other words, if the content of diamine unit (X1) is less than 0.1 mol%, it is difficult to sufficiently increase the crystallization rate; if it is 36 mol% or more, there is a risk of excessively reducing the heat resistance. From the viewpoint of producing a polyamide with a better balance between heat resistance and crystallization rate, the diamine unit (X) contains preferably 0.5 mol% or more, more preferably 1 mol% or more, further preferably 3 mol% or more, and even more preferably 5 mol% or more. Furthermore, from the above perspective, in the diamine unit (X), the diamine unit (X1) is preferably 35 mol% or less, more preferably 30 mol% or less, further preferably 25 mol% or less, even more preferably 20 mol% or less, more preferably 18 mol% or less, even more preferably 15 mol% or less, and even more preferably 10 mol% or less. In other words, the above-mentioned diamine unit (X) contains preferably 0.5 to 35 mol%, more preferably 0.5 to 30 mol%, further preferably 0.5 to 25 mol%, even more preferably 0.5 to 20 mol%, even more preferably 0.5 to 18 mol%, even more preferably 1 to 18 mol%, even more preferably 1 to 15 mol%, and particularly preferably 1 to 10 mol% of diamine unit (X1). Furthermore, as one of the preferred embodiments, when the diamine unit (X1) is derived from a structural unit of at least one diamine selected from the group consisting of 2-ethyl-1,7-heptanediamine and 2-propyl-1,6-hexanediamine, an example of the content of each structural unit is as follows: The content of the structural unit derived from 2-ethyl-1,7-heptanediamine in the diamine unit (X) is preferably 0.5 mol% or more, more preferably 2 mol% or more. Furthermore, the above content is preferably 20 mol% or less, more preferably 16 mol% or less, further preferably 15 mol% or less, even more preferably 12 mol% or less, and even more preferably 10 mol% or less. In other words, the content of the structural unit derived from 2-ethyl-1,7-heptanediamine in the diamine unit (X) is preferably 0.5 to 20 mol%. The content of structural units derived from 2-propyl-1,6-hexanediamine in the diamine unit (X) is preferably 0.1 mol% or more, more preferably 0.5 mol% or more. Furthermore, the above content is preferably 5 mol% or less, more preferably 3 mol% or less, further preferably 2 mol% or less, and even more preferably 1.5 mol% or less. In other words, the content of structural units derived from 2-propyl-1,6-hexanediamine in the diamine unit (X) is preferably 0.1 to 5 mol%. (Diamine Unit (X2)) Polyamide (A) may also contain a diamine unit other than the diamine unit (X1) (hereinafter also referred to as "diamine unit (X2)") as the diamine unit (X). From the viewpoint of facilitating the polymerization reaction of dicarboxylic acid and diamine, the diamine unit (X2) is preferably derived from a diamine with 6 to 10 carbon atoms, more preferably 8 to 10 carbon atoms, and even more preferably 9 carbon atoms. Examples of diamine units (X2) include structural units derived from at least one of the following groups: linear aliphatic diamines, branched aliphatic diamines other than the aliphatic diamines constituting the diamine unit (X), alicyclic diamines, and aromatic diamines. Examples of linear aliphatic diamines include ethylenediamine, 1,3-propanediamine, 1,4-butanediamine, 1,5-pentanediamine, 1,6-hexanediamine, 1,7-heptanediamine, 1,8-octanediamine, 1,9-nonanediamine, 1,10-decanediamine, 1,11-undecanediamine, 1,12-dodecanediamine, 1,13-tridecanediamine, 1,14-tetradecanediamine, 1,15-pentadecanediamine, 1,16-hexadecanediamine, 1,17-heptadecanediamine, and 1,18-octadecanediamine. Examples of branched aliphatic diamines include 1,2-propanediamine, 1-butyl-1,2-ethylenediamine, 1,1-dimethyl-1,4-butanediamine, 1-ethyl-1,4-butanediamine, 1,2-dimethyl-1,4-butanediamine, 1,3-dimethyl-1,4-butanediamine, 1,4-dimethyl-1,4-butanediamine, 2-methyl-1,3-propanediamine, 2-methyl-1,4-butanediamine, 2,3-dimethyl-1,4-butanediamine, 2-methyl-1,5-pentanediamine, 3-methyl-1,5-pentanediamine, 2-butyl-2-ethyl-1,5-pentanediamine, 2,5-dimethyl-1,6-hexanediamine, 2,4-dimethyl-1,6-hexanediamine, and 3,3-dimethyl- 1,6-Hexanediamine, 2,2-Dimethyl-1,6-Hexanediamine, 2,2,4-Trimethyl-1,6-Hexanediamine, 2,4,4-Trimethyl-1,6-Hexanediamine, 2-Methyl-1,8-Octadiamine, 3-Methyl-1,8-Octadiamine, 1,3-Dimethyl-1,8-Octadiamine, 1,4-Dimethyl-1,8-Octadiamine, 2,4-Dimethyl-1,8-Octadiamine, 3,4-Dimethyl-1,8-Octadiamine, 4,5-Dimethyl-1,8-Octadiamine, 2,2-Dimethyl-1,8-Octadiamine, 3,3-Dimethyl-1,8-Octadiamine, 4,4-Dimethyl-1,8-Octadiamine, 2-Methyl-1,9-Nonadiamine, 5-Methyl-1,9-Nonadiamine. Examples of alicyclic diamines include: cyclohexanediamine, methylcyclohexanediamine, norbornenedimethylamine, tricyclodecanedimethyldiamine, bis(4-amino-3-ethylcyclohexyl)methane, and bis(4-amino-3-ethyl-5-methylcyclohexyl)methane. Examples of aromatic diamines include p-phenylenediamine, m-phenylenediamine, p-xylylenediamine, m-phenylenediamine, 4,4'-diaminodiphenylmethane, 4,4'-diaminodiphenyl ether, and 4,4'-methylenedi-2,6-diethylaniline. The structural unit derived from these diamines may be only one type or two or more types. Of the aforementioned diamine units (X2), it is more preferably a structural unit derived from at least one diamine selected from the group consisting of straight-chain aliphatic diamines and branched aliphatic diamines with methyl branches. From the viewpoint that the effects of the present invention can be more significantly realized, the aforementioned other diamine units are further preferably derived from structural units of at least one diamine selected from the group consisting of 1,6-hexanediamine, 1,9-nonanediamine, 1,10-decanediamine, 2-methyl-1,5-pentanediamine, and 2-methyl-1,8-octanediamine. <Dicarboxylic acid unit (Y)> The dicarboxylic acid unit (Y) may comprise any dicarboxylic acid unit. The dicarboxylic acid unit (Y) may comprise, for example, a structural unit derived from at least one dicarboxylic acid selected from the group consisting of aliphatic dicarboxylic acids, aromatic dicarboxylic acids and alicyclic dicarboxylic acids. Examples of aliphatic dicarboxylic acids include oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, octanoic acid, azelaic acid, sebacic acid, undecanedicarboxylic acid, dodecanedicarboxylic acid, dimethylmalonic acid, 2,2-diethylsuccinic acid, 2,2-dimethylglutaric acid, 2-methyl adipic acid, and trimethyl adipic acid. Examples of aromatic dicarboxylic acids include terephthalic acid, isophthalic acid, diphenylic acid, 4,4'-biphenyl-4,4'-dicarboxylic acid, diphenylmethane-4,4'-dicarboxylic acid, 1,2-naphthalenedicarboxylic acid, 1,3-naphthalenedicarboxylic acid, 1,4-naphthalenedicarboxylic acid, 1,5-naphthalenedicarboxylic acid, 1,6-naphthalenedicarboxylic acid, 1,7-naphthalenedicarboxylic acid, 1,8-naphthalenedicarboxylic acid, 2,3-naphthalenedicarboxylic acid, 2,6-naphthalenedicarboxylic acid, and 2,7-naphthalenedicarboxylic acid. Examples of other aromatic dicarboxylic acids include 2,3-furandicarboxylic acid, 2,4-furandicarboxylic acid, 2,5-furandicarboxylic acid, and 3,4-furandicarboxylic acid. Examples of alicyclic dicarboxylic acids include 1,3-cyclopentanedicarboxylic acid, 1,3-cyclohexanedicarboxylic acid, 1,4-cyclohexanedicarboxylic acid, cycloheptanedicarboxylic acid, cyclooctanedicarboxylic acid, and cyclodecanedicarboxylic acid. The structural units derived from these dicarboxylic acids may contain only one type or more than two types. From the viewpoint that the effects of the present invention can be more readily and significantly realized, the dicarboxylic acid unit (Y) preferably comprises a structural unit of at least one dicarboxylic acid selected from the group consisting of aromatic dicarboxylic acids and alicyclic dicarboxylic acids, and more preferably comprises a structural unit of at least one dicarboxylic acid selected from the group consisting of terephthalic acid, cyclohexanedicarboxylic acid and naphthalenedicarboxylic acid. From the viewpoint that this invention can more significantly enhance the effects of the present invention, the total content of structural units derived from aliphatic dicarboxylic acids, aromatic dicarboxylic acids, and alicyclic dicarboxylic acids in the dicarboxylic acid unit (Y) is preferably 80 mol% or more, more preferably 90 mol%, further preferably 95 mol% or more, and may also be 100 mol%. In other words, the total content of structural units derived from aliphatic dicarboxylic acids, aromatic dicarboxylic acids, and alicyclic dicarboxylic acids in the dicarboxylic acid unit (Y) is preferably 80 to 100 mol%. Similarly, from the same viewpoint, the total content of structural units derived from terephthalic acid, cyclohexanedicarboxylic acid, and naphthalenedicarboxylic acid in the dicarboxylic acid unit (Y) is preferably 80 mol% or more, more preferably 90 mol%, further preferably 95 mol% or more, and may also be 100 mol. In other words, the total content of structural units derived from terephthalic acid, cyclohexanedicarboxylic acid and naphthalenedicarboxylic acid in the dicarboxylic acid unit (Y) is preferably 80 to 100 moles. The molar ratio of diamine units (X) to dicarboxylic acid units (Y) in polyamide (A) [diamine unit (X) / dicarboxylic acid unit (Y)] is preferably 45 / 55 to 55 / 45. If the molar ratio of diamine units (X) to dicarboxylic acid units (Y) is within the above range, the polymerization reaction proceeds well, and polyamides with the desired excellent physical properties can be easily obtained. Furthermore, the molar ratio of diamine units (X) to dicarboxylic acid units (Y) can be adjusted according to the blending ratio (molar ratio) of the diamine and dicarboxylic acid in the raw materials. The total ratio of diamine units (X) and dicarboxylic acid units (Y) in polyamide (A) (the ratio of the total moles of dicarboxylic acid units (Y) and diamine units (X) to the total moles of all structural units constituting polyamide (A)) is preferably 70 mol% or more, more preferably 80 mol% or more, further preferably 90 mol% or more, even more preferably 95 mol% or more, and may even be 100 mol%. By achieving the above-mentioned total ratio of diamine units (X) and dicarboxylic acid units (Y), polyamide (A) with superior physical properties can be produced. In other words, the total ratio of diamine units (X) and dicarboxylic acid units (Y) in polyamide (A) is preferably 70 to 100 mol. <Other Structural Units> In addition to the diamine unit (X) and the dicarboxylic acid unit (Y), polyamide (A) may further include other structural units. For example, it may further include aminocarboxylic acid units, polycarboxylic acid units, and end-capping agent units. (Aminocarboxylic acid unit) Examples of the aforementioned aminocarboxylic acid unit include endoamines such as caprolactam and lauroylamine, and aminocarboxylic acids such as 11-aminoundecanoic acid and 12-aminododecanoic acid. The content of the aminocarboxylic acid unit in polyamide (A) is preferably 40 mol% or less, and more preferably 20 mol% or less, relative to 100 mol% of the total diamine unit (X) and dicarboxylic acid unit (Y) constituting polyamide (A). In other words, the content of the aminocarboxylic acid unit in polyamide (A) is preferably 0 to 40 mol% relative to 100 mol% of the total diamine unit (X) and dicarboxylic acid unit (Y) constituting polyamide (A). (Polycarboxylic acid unit) Without impairing the effects of the present invention, polyamide may also be able to be melt-formed into structural units derived from trivalent or higher polycarboxylic acids such as trimellitic acid, trimesic acid, and pyromellitic acid. (End-capping agent unit) Polyamide (A) may also contain structural units derived from an end-capping agent (end-capping agent unit). The end-capping agent unit is preferably 1.0 mol% or more, more preferably 2.0 mol% or more, and preferably 10 mol% or less, more preferably 5.0 mol% or less, relative to 100 mol% of diamine units (X). In other words, the end-capping agent unit is preferably 1.0 to 10 mol% relative to 100 mol% of diamine units (X). If the content of the end-capping agent unit is within the above range, it is easy to obtain polyamide (A) with the desired excellent physical properties. The content of the end-capping agent unit can be made within the above-mentioned desired range by appropriately adjusting the amount of end-capping agent when feeding it into the polymerization raw materials. Furthermore, considering that monomer components will volatilize during polymerization, it is desirable to fine-tune the amount of end-capping agent fed into the obtained polyamide (A) by introducing the desired amount of end-capping agent unit. As a method for determining the content of end-capping agent units in polyamide (A), for example, as shown in Japanese Patent Application Publication No. 7-228690, one can measure the viscosity of the solution, calculate the total amount of end groups from its relationship with the number average molecular weight, and then subtract the amount of amine and carboxyl groups determined by titration; or use... 1 Of the methods, H-NMR, which are based on the integral values ​​of the signals corresponding to the diamine unit and the end-capping agent unit respectively, is preferred, especially the latter. Regarding end-capping agents, monofunctional compounds that react with terminal amine or carboxyl groups can be used. Specifically, examples include monocarboxylic acids, acid anhydrides, monoisocyanates, monoacid halides, monoesters, monoalcohols, and monoamines. From the viewpoint of reactivity and the stability of the capped end, monocarboxylic acids are preferred as end-capping agents for terminal amine groups, and monoamines are preferred as end-capping agents for terminal carboxyl groups. From the viewpoint of ease of handling, monocarboxylic acids are even more preferred as end-capping agents. For monocarboxylic acids used as end-capping agents, there are no particular limitations as long as they are reactive with an amino group. Examples include aliphatic monocarboxylic acids such as acetic acid, propionic acid, butyric acid, valeric acid, hexanoic acid, octanoic acid, lauric acid, tridecanoic acid, myristic acid, palmitic acid, stearic acid, trimethylacetic acid, and isobutyric acid; alicyclic monocarboxylic acids such as cyclopentanecarboxylic acid and cyclohexanecarboxylic acid; aromatic monocarboxylic acids such as benzoic acid, toluic acid, α-naphthylcarboxylic acid, β-naphthylcarboxylic acid, methylnaphthylcarboxylic acid, and phenylacetic acid; and any mixtures thereof. Among these, from the perspectives of reactivity, stability of the capped end, and price, it is preferable to select at least one from the group consisting of acetic acid, propionic acid, butyric acid, valeric acid, hexanoic acid, octanoic acid, lauric acid, tridecanoic acid, myristic acid, palmitic acid, stearic acid, and benzoic acid. Regarding the monoamines used as end-capping agents, there are no particular limitations as long as they are reactive with carboxyl groups. Examples include aliphatic monoamines such as methylamine, ethylamine, propylamine, butylamine, hexylamine, octylamine, decylamine, stearylamine, dimethylamine, diethylamine, dipropylamine, and dibutylamine; alicyclic monoamines such as cyclohexylamine and dicyclohexylamine; aromatic monoamines such as aniline, toluidine, diphenylamine, and naphthylamine; and any mixtures thereof. Among these, from the perspectives of reactivity, high boiling point, stability of the capped end, and price, it is preferable to select at least one from the group consisting of butylamine, hexylamine, octylamine, decylamine, stearylamine, cyclohexylamine, and aniline. <Polyamide (A) content> The content of polyamide (A) in the total polyamide composition of this embodiment is preferably 30 to 99.9% by mass, more preferably 40 to 99.8% by mass, and even more preferably 45 to 99.7% by mass, from the viewpoint of easily ensuring good formability, heat resistance and chemical resistance. (Physical Properties of Polyamide (A)) The intrinsic viscosity of polyamide (A) is preferably 0.5 dl / g or more, more preferably 0.7 dl / g or more. Furthermore, it is preferably 2.0 dl / g or less, more preferably 1.5 dl / g or less. In other words, the intrinsic viscosity of polyamide (A) is preferably 0.5 to 2.0 dl / g. With an intrinsic viscosity within the above range, it becomes easier to produce polyamides with desired superior physical properties. The intrinsic viscosity of polyamide (A) can be determined by measuring the flow time of a solution using concentrated sulfuric acid at a concentration of 0.2 g / dl and a temperature of 30°C as the solvent, and more specifically, by the method described in the examples. Polyamide (A) preferably has a melting point of 250°C or higher, more preferably 280°C or higher. By having a melting point within this range, polyamide (A) with excellent heat resistance can be produced. There is no particular upper limit to the melting point of polyamide (A), but considering factors such as formability, it is preferably below 330°C. In other words, the melting point of polyamide (A) is preferably 250–330°C, more preferably 280–330°C. The melting point of polyamide can be determined using a differential scanning calorimetry (DSC) device as the peak temperature of the endothermic peak that appears when the temperature is increased at a rate of 10°C / minute; more specifically, it can be determined using the method described in the examples. The glass transition temperature of polyamide (A) is preferably 110°C or higher, and more preferably 120°C or higher. By utilizing a glass transition temperature within the above range, polyamide (A) with excellent heat resistance can be produced. The glass transition temperature of polyamide (A) can be determined using a differential scanning calorimetry (DSC) device as the temperature at which the inflection point occurs when the temperature is increased at a rate of 20°C / minute, and more specifically, it can be determined using the method described in the examples. The optimal crystallization rate for polyamide (A) is 0.02℃. -1 The above is preferred to be 0.04℃. -1 The above describes how polyamides with excellent production properties can be easily obtained when the crystallization rate is within the aforementioned range. The crystallization rate can be determined using the following formula (Equation 1). Crystallization rate (°C) -1 = 1 / (melting point (°C) - crystallization temperature (°C)) (Equation 1) From the viewpoint of heat resistance and productivity, the crystallization temperature of polyamide (A) is preferably above 200°C, more preferably above 210°C, further preferably above 220°C, and preferably below 310°C, more preferably below 300°C, and even more preferably below 290°C. In other words, the crystallization temperature of polyamide (A) is preferably 200–310°C. The crystallization temperature of polyamide (A) can be determined using a differential scanning calorimetry (DSC) device as the peak temperature of the exothermic peak that appears when the temperature is increased to a specified temperature at a rate of 10°C / min and then cooled down. More specifically, it can be determined using the method described in the examples. The amount of terminal amino groups in the polyamide (A) molecular chain ([NH4+]) 2) Preferably, the amount of terminal amino groups is 5 μmol / g or more, more preferably 10 μmol / g or more. Also, preferably 160 μmol / g or less, more preferably 100 μmol / g or less, and even more preferably 90 μmol / g or less. In other words, the amount of terminal amino groups in the molecular chain of polyamide (A) is preferably 5 to 160 μmol / g. If the amount of terminal amino groups is above the lower limit mentioned above, when the polyamide composition contains a filler, sufficient adhesion to the filler, especially to fibrous fillers, can be ensured, and the mechanical properties are less likely to decrease. Furthermore, if the amount of terminal amino groups is below the upper limit mentioned above, the intermolecular cross-linking reaction will be inhibited, and the heat resistance and the stability of the melt viscosity during processing will be less likely to decrease. The amount of terminal amino groups in polyamide (A) can be determined by titrating a phenol solution containing polyamide (A) with an aqueous hydrochloric acid solution, or more specifically by the method described in the examples. Polyamide (A) preferably has a terminal carboxyl group content ([COOH]) of 2 μmol / g or more, more preferably 5 μmol / g or more, and more preferably 10 μmol / g or more. It is also preferably 100 μmol / g or less, and more preferably 90 μmol / g or less. In other words, the terminal carboxyl group content of the polyamide (A) molecular chain is preferably 2 to 100 μmol / g. If the terminal carboxyl group content is above the lower limit mentioned above, when the polyamide composition contains a filler, sufficient adhesion to the filler, especially to fibrous fillers, can be ensured, and the mechanical properties are less likely to decrease. Furthermore, if the terminal carboxyl group content is below the upper limit mentioned above, hydrolysis under acidic conditions is suppressed, and chemical resistance is less likely to decrease. The amount of terminal carboxyl groups in polyamide (A) can be determined by titrating a cresol solution containing polyamide (A) with potassium hydroxide solution, or more specifically by the method described in the examples. Polyamide (A), the amount of terminal amino groups in its molecular chain ([NH4+]) 2) The ratio of the amount of terminal carboxyl group ([COOH]) to the amount of terminal carboxyl group ([NH) The ratio of [NH4OH] to [COOH] is preferably 0.1 or higher, more preferably 0.3 or higher. Furthermore, it is preferably 50 or lower, more preferably 10 or lower, and even more preferably 6 or lower. In other words, the above ratio ([NH4OH]) in polyamide (A) is... 2)] / [COOH]), preferably 0.1~50. <Method for Manufacturing Polyamide (A)> Polyamide (A) can be manufactured using any method known as a method for manufacturing polyamide. For example, it can be manufactured by melt polymerization, solid-state polymerization, melt extrusion polymerization, etc., using dicarboxylic acid and diamine as raw materials. Among these, solid-state polymerization is preferred from the viewpoint that it can better suppress thermal degradation during polymerization. Polyamide (A) can be manufactured, for example, by initially adding a diamine, a dicarboxylic acid, and a catalyst and end-capping agent as needed to produce a nylon salt, followed by heating and polymerization at a temperature of 200–250°C to form a prepolymer, which is then further polymerized in a solid-state manner or by using a melt extruder. When polymerizing in the final stage by solid-state polymerization, it is preferable to carry out the polymerization under reduced pressure or with an inert gas flow. If the polymerization temperature is in the range of 200–280°C, the polymerization rate is high, the productivity is excellent, and coloring and gelation can be effectively suppressed. For the final stage of polymerization by melt extruder, the polymerization temperature is preferably below 370°C. Under such conditions, polymerization hardly decomposes, and polyamide with minimal deterioration can be obtained. Examples of catalysts that can be used in the manufacture of the polyamide of this embodiment include phosphoric acid, phosphorous acid, hypophosphorous acid, or their salts or esters. Examples of the aforementioned salts or esters include salts of phosphoric acid, phosphorous acid, or hypophosphorous acid with metals such as potassium, sodium, magnesium, vanadium, calcium, zinc, cobalt, manganese, tin, tungsten, germanium, titanium, and antimony; ammonium salts of phosphoric acid, phosphorous acid, or hypophosphorous acid; and ethyl, isopropyl, butyl, hexyl, isodecyl, octadecyl, decyl, stearyl ester, and phenyl esters of phosphoric acid, phosphorous acid, or hypophosphorous acid. The amount of the catalyst used is preferably 0.01% by mass or more, more preferably 0.05% by mass or more, and even more preferably 1.0% by mass or less, and more preferably 0.5% by mass or less, relative to 100% by mass of the total raw materials. In other words, the amount of the catalyst used is preferably 0.01 to 1.0% by mass relative to 100% by mass of the total raw materials. If the amount of catalyst used is above the lower limit mentioned above, the polymerization system proceeds well. If the amount of catalyst used is below the upper limit mentioned above, it becomes less likely that impurities originating from the catalyst will be generated. For example, in the case of forming a polyamide composition into a film, adverse conditions caused by the aforementioned impurities can be prevented. [Organic heat stabilizer (B)] For the organic heat stabilizer (B) contained in the polyamide composition of this embodiment, known compounds may be used, but preferably selected from at least one of the group consisting of phenolic heat stabilizers (B1), phosphorus heat stabilizers (B2), sulfur heat stabilizers (B3) and amine heat stabilizers (B4). • Phenolic Heat Stabilizers (B1) Examples of phenolic heat stabilizers (B1) include hindered phenolic compounds. Hindered phenolic compounds impart heat resistance and light resistance to polyamides and resin compositions containing polyamides. Examples of hindered phenolic compounds include 2,2-thio-diethylenebis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], N,N'-hexane-1,6-diylbis[3-(3,5-di-tert-butyl-4-hydroxyphenylpropionamide)], and neopentyl tert-tetra[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate]. (pentaerythrityl-tetrakis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate]), N,N'-hexamethylenebis(3,5-di-tert-butyl-4-hydroxyphenyl)propionamide, triethylene glycol bis(3-tert-butyl-4-hydroxy-5-methylphenyl)propionate, hexamethylenebis(3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate), 3,9-bis{2-[3-(3 [-Tri-butyl-4-hydroxy-5-methylphenyl]propoxy]-1,1-dimethylethyl}-2,4,8,10-tetraoxaspiro[5.5]undecane, tris(3,5-di-tri-butyl-4-hydroxybenzyl)triisocyanate, 3,5-di-tri-butyl-4-hydroxybenzylphosphonate-diethyl ester, 1,3,5-trimethyl-2,4,6-tris(3,5-di-tri-butyl-4-hydroxybenzyl)benzene, 1,3,5-tris(4-tri-butyl-3-hydroxy-2,6-dimethylbenzyl)isocyanuric acid, etc. The phenolic heat stabilizer (B1) can be used alone or in combination with two or more. Particularly from the viewpoint of improving heat resistance, 3,9-bis{2-[3-(3-tributyl-4-hydroxy-5-methylphenyl)propoxy]-1,1-dimethylethyl}-2,4,8,10-tetraoxaspiro[5.5]undecane is preferred. When using the phenolic heat stabilizer (B1), its content relative to 100 parts by weight of polyamide (A) is preferably 0.01 to 2 parts by weight, more preferably 0.1 to 1 part by weight. Within the above range, heat resistance is further improved. • Phosphorus-based heat stabilizer (B2) Examples of phosphorus-based heat stabilizers (B2) include: monosodium phosphate, disodium phosphate, trisodium phosphate, sodium phosphite, calcium phosphite, magnesium phosphite, manganese phosphite, neopentyltetrol-type phosphite compounds, trioctyl phosphite, trilauryl phosphite, octyl diphenyl phosphite, triisodecyl phosphite, phenyl diisodecyl phosphite, phenyl di(decayl) phosphite, diphenyl isooctyl phosphite, diphenyl isoodecyl phosphite, diphenyl(decayl) phosphite, triphenyl phosphite, trioctadecyl phosphite, tridecyl phosphite, tri(nonylphenyl) phosphite, tri(2,4-di-tertiary butylphenyl) phosphite, tri(2,4-di-tertiary butyl-5-methylphenyl) phosphite, tri(butoxyethyl) phosphite, and 4,4'-butylene-bis(3-methyl-6-tertiary butylphenyl-tetra-decayl) Diphosphite, tetra(C12-C15 mixed alkyl)-4,4'-isopropyl diphenyl diphosphite, 4,4'-isopropyl bis(2-tertiary butylphenyl) di(nonylphenyl) phosphite, tri(biphenyl) phosphite, tetra(decayl)-1,1,3-tris(2-methyl-5-tertiary butyl-4-hydroxyphenyl)butane diphosphite, tetra(decayl)-4,4'-butyl bis(3-methyl-6-tertiary butylphenyl) diphosphite, tetra(C1-C15 mixed alkyl)-4,4'-isopropyl diphenyl diphosphite, tri(mono- and di-mixed nonylphenyl) phosphite, 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide Tris(3,5-di-tertiary butyl-4-hydroxyphenyl) phosphite, hydrogenated 4,4'-isopropylidene diphenyl polyphosphite, bis(octylphenyl)bis(4,4'-butylidene bis(3-methyl-6-tertiary butylphenyl))1,6-hexanol diphosphite, hexa-tetrazol-1,1,3-tris(2-methyl-4-hydroxy-5-tertiary butylphenyl) diphosphite, tris(4,4'-isopropylidene bis(2-tertiary butylphenyl)) phosphite, tris(1,3-stearyloxyisopropyl) phosphite, 2,2-methylenebis(4,6-di-tertiary butylphenyl) Octyl phosphite, 2,2-methylenebis(3-methyl-4,6-di-tertiary butylphenyl)-2-ethylhexyl phosphite, tetra(2,4-di-tertiary butyl-5-methylphenyl)-4,4'-biphenyl diphosphite, tetra(2,4-di-tertiary butylphenyl)-4,4'-biphenyl diphosphite, 6-[3-(3-tertiary butyl-4-hydroxy-5-methylphenyl)propoxy]-2,4,8,10-tetra-tertiary butyldibenzo[d,f][1,3,2]-dioxaphosphepin, etc. Phosphorus-based heat stabilizers (B2) can be used alone or in combination with two or more. From the viewpoint of further improving heat resistance, neopentyl tetrol-type phosphite compounds and tris(2,4-di-tert-butylphenyl) phosphite are preferred for phosphorus-based heat stabilizers (B2). Examples of neopentyl tetrahydric phosphites include: (2,6-di-tert-butyl-4-methylphenyl)phenylneopentyl tetrahydric diphosphite, (2,6-di-tert-butyl-4-methylphenyl)methylneopentyl tetrahydric diphosphite, (2,6-di-tert-butyl-4-methylphenyl)2-ethylhexylneopentyl tetrahydric diphosphite, (2,6-di-tert-butyl-4-methylphenyl)isodecylneopentyl tetrahydric diphosphite, (2,6-di-tert-butyl-4-methylphenyl)laurylneopentyl tetrahydric diphosphite, (2,6-di-tert-butyl-4-methylphenyl)laurylneopentyl tetrahydric diphosphite, and (2,6-di-tert-butyl-4-methylphenyl)2-ethylhexylneopentyl tetrahydric diphosphite. (2,6-di-tert-butyl-4-methylphenyl)isotridecylneopentyltetrafluoroethylene diphosphite, (2,6-di-tert-butyl-4-methylphenyl)stearylneopentyltetrafluoroethylene diphosphite, (2,6-di-tert-butyl-4-methylphenyl)cyclohexylneopentyltetrafluoroethylene diphosphite, (2,6-di-tert-butyl-4-methylphenyl)benzylneopentyltetrafluoroethylene diphosphite, (2,6-di-tert-butyl-4-methylphenyl)ethylceroxoxeneneopentyltetrafluoroethylene diphosphite, (2,6-di-tert-butyl-4-methylphenyl)butylcarbitolneopentyltetrafluoroethylene diphosphite, (2,6-di-tert-butyl-4-methylphenyl)butylcarbitolneopentyltetrafluoroethylene diphosphite, (2,6-di-tert-butyl-4-methylphenyl)benzyl ... (2,6-di-tert-butyl-4-methylphenyl)nonylphenylneopentyltetraethanol diphosphite, bis(2,6-di-tert-butyl-4-methylphenyl)neopentyltetraethanol diphosphite, bis(2,6-di-tert-butyl-4-ethylphenyl)neopentyltetraethanol diphosphite, (2,6-di-tert-butyl-4-methylphenyl)(2,6-di-tert-butylphenyl)neopentyltetraethanol diphosphite, (2,6-di-tert-butyl-4-methylphenyl)(2,4-di-tert-butylphenyl)neopentyltetraethanol diphosphite Examples of neopentyltetraethylene diphosphite include (2,6-di-tert-butyl-4-methylphenyl)(2,4-di-tert-octylphenyl)neopentyltetraethylene diphosphite, (2,6-di-tert-butyl-4-methylphenyl)(2-cyclohexylphenyl)neopentyltetraethylene diphosphite, (2,6-di-tert-pentyl-4-methylphenyl)phenylneopentyltetraethylene diphosphite, bis(2,4-diisopropylphenylphenyl)neopentyltetraethylene diphosphite, bis(2,6-di-tert-pentyl-4-methylphenyl)neopentyltetraethylene diphosphite, and bis(2,6-di-tert-octyl-4-methylphenyl)neopentyltetraethylene diphosphite. These can be used alone or in combination with two or more other types. Preferred bis(2,4-diisopropylphenylphenyl)neopentetrol diphosphite, bis(2,6-di-tert-butyl-4-methylphenyl)neopentetrol diphosphite, bis(2,6-di-tert-butyl-4-ethylphenyl)neopentetrol diphosphite, bis(2,6-di-tert-pentyl-4-methylphenyl)neopentetrol diphosphite, bis(2,6-di-tert-octyl-4-methylphenyl)neopentetrol diphosphite, and more preferably bis(2,6-di-tert-butyl-4-methylphenyl)neopentetrol diphosphite. When using a phosphorus-based heat stabilizer (B2), its content relative to 100 parts by weight of polyamide (A) is preferably 0.01 to 2 parts by weight, more preferably 0.1 to 1 part by weight. Within the above range, heat resistance can be further improved. • Sulfur-based heat stabilizers (B3) Examples of sulfur-based heat stabilizers (B3) include: distearate 3,3'-thiodipropionate, neopentyltetra(3-lauryl thiopropionate), 2-mercaptobenzimidazole, di-dodecyl 3,3'-thiodipropionate, di-tetrazyl 3,4'-thiodipropionate, 2,2-bis[[3-(dodecylthio)-1-oxopropoxy]methyl]-1,3-propanediol ester, etc. Sulfur-based heat stabilizer (B3) can be used alone or in combination with two or more. When using sulfur-based heat stabilizer (B3), its content relative to 100 parts by weight of polyamide (A) is preferably 0.02 to 4 parts by weight, more preferably 0.2 to 2 parts by weight. When within the above range, the heat resistance can be further improved. • Amine-based heat stabilizers (B4) Examples of amine-based heat stabilizers (B4) include: 4,4'-bis(α,α-dimethylbenzyl)diphenylamine (Nocrac CD, manufactured by Ouchi Shinsei Chemical Industry Co., Ltd.), N,N'-di-2-naphthyl-p-phenylenediamine (Nocrac White, manufactured by Ouchi Shinsei Chemical Industry Co., Ltd.), N,N'-diphenyl-p-phenylenediamine (Nocrac DP, manufactured by Ouchi Shinsei Chemical Industry Co., Ltd.), N-phenyl-1-naphthylamine (Nocrac PA, manufactured by Ouchi Shinsei Chemical Industry Co., Ltd.), N-phenyl-N'-isopropyl-p-phenylenediamine (Nocrac 810-NA, manufactured by Ouchi Shinsei Chemical Industry Co., Ltd.), and N-phenyl-N'-(1,3-dimethylbutyl)-p-phenylenediamine (Nocrac 810-NA, manufactured by Ouchi Shinsei Chemical Industry Co., Ltd.). 6C et al.), N-phenyl-N'-(3-methacryloxy-2-hydroxypropyl)-p-phenylenediamine (Nocrac G-1, manufactured by Daichi Shinshin Chemical Industry Co., Ltd.), 4-acetoxy-2,2,6,6-tetramethylpiperidine, 4-stearyloxy-2,2,6,6-tetramethylpiperidine, 4-propenyloxy-2,2,6,6-tetramethylpiperidine, 4-(phenylacetoxy)-2,2,6,6-tetramethylpiperidine, 4-benzyloxy-2,2,6,6-tetramethylpiperidine, 4-methoxy-2,2,6,6-tetramethylpiperidine, 4-stearyloxy-2,2,6,6-tetramethylpiperidine Methylpiperidine, 4-cyclohexyloxy-2,2,6,6-tetramethylpiperidine, 4-benzyloxy-2,2,6,6-tetramethylpiperidine, 4-phenoxy-2,2,6,6-tetramethylpiperidine, 4-(ethylaminomethoxy)-2,2,6,6-tetramethylpiperidine, 4-(cyclohexylaminomethoxy)-2,2,6,6-tetramethylpiperidine, 4-(phenylaminomethoxy)-2,2,6,6-tetramethylpiperidine, bis(2,2,6,6- Tetramethyl-4-piperidinyl) carbonate, bis(2,2,6,6-tetramethyl-4-piperidinyl) oxalate, bis(2,2,6,6-tetramethyl-4-piperidinyl) malonate, bis(2,2,6,6-tetramethyl-4-piperidinyl) sebacate, bis(2,2,6,6-tetramethyl-4-piperidinyl) adipate, bis(2,2,6,6-tetramethyl-4-piperidinyl) terephthalate, 1,2-bis(2,2,6,6-tetramethyl) α,α'-bis(2,2,6,6-tetramethyl-4-piperidinyloxy)-p-xylene, bis(2,2,6,6-tetramethyl-4-piperidinyl)methylphenyl-2,4-diaminocarboxylate, bis(2,2,6,6-tetramethyl-4-piperidinyl)hexamethylene-1,6-diaminocarboxylate, tris(2,2,6,6-tetramethyl-4-piperidinyl)phenyl-1,3,5-tricarboxylate, tris(2,2,6,6,Condensations of 6-tetramethyl-4-piperidinyl)benzene-1,3,4-tricarboxylic acid ester, 1-[2-{3-(3,5-di-tri-butyl-4-hydroxyphenyl)propoxy}butyl]-4-[3-(3,5-di-tri-butyl-4-hydroxyphenyl)propoxy]2,2,6,6-tetramethylpiperidine, condensates of 1,2,3,4-butanetetracarboxylic acid with 1,2,2,6,6-pentamethyl-4-piperidinol with β,β,β',β'-tetramethyl-3,9-[2,4,8,10-tetraoxaspiro[5,5]undecane]diethanol, etc. Amine-based heat stabilizer (B4) can be used alone or in combination with two or more. When using amine-based heat stabilizer (B4), its content relative to 100 parts by weight of polyamide (A) is preferably 0.01 to 2 parts by weight, more preferably 0.1 to 1 part by weight. Within the above range, the heat resistance can be further improved. Relative to 100 parts by weight of polyamide (A), the polyamide composition of this embodiment preferably contains 0.05 to 5 parts by weight of the aforementioned organic heat stabilizer (B), more preferably 0.1 to 3 parts by weight. If the content of the organic heat stabilizer (B) is within the above range, the heat resistance of the polyamide composition can be further improved. When using multiple organic heat stabilizers (B), their total amount within the above range is sufficient. [Other Additives] The above polyamide composition may contain other additives as needed, in addition to polyamide (A) and organic heat stabilizer (B). Other additives include fillers such as inorganic or organic fibrous fillers; stabilizers such as copper compounds; colorants; ultraviolet absorbers; light stabilizers; antistatic agents; flame retardants such as brominated polymers, antimony oxide, metal hydroxides, and phosphonates; flame retardant additives; nucleating agents; plasticizers; lubricants; slip agents; dispersants; oxygen absorbers; hydrogen sulfide adsorbents; crystallization inhibitors; impact modifiers such as α-olefin copolymers and rubbers; and anti-drip agents such as fluoropolymers. The aforementioned fibrous filler may be surface-treated using silane coupling agents, titanate coupling agents, etc. The use of silane coupling agents is not particularly limited, and examples include: aminosilane coupling agents such as γ-aminopropyltriethoxysilane, γ-aminopropyltrimethoxysilane, and N-β-(aminoethyl)-γ-aminopropylmethyldimethoxysilane; mercaptosilane coupling agents such as γ-mercaptopropyltrimethoxysilane and γ-mercaptopropyltriethoxysilane; epoxysilane coupling agents; and vinylsilane coupling agents. One of these silane coupling agents may be used alone, or two or more may be used in combination. Among the aforementioned silane coupling agents, aminosilane coupling agents are preferred. The fibrous filler may also be treated with a sizing agent if necessary. Examples of sizing agents include: copolymers comprising unsaturated vinyl monomer units containing carboxylic anhydride and unsaturated vinyl monomer units other than those containing carboxylic anhydride as structural units; epoxy compounds; polyurethane resins; homopolymers of acrylic acid; copolymers of acrylic acid with other comonomers; and salts of primary, secondary, or tertiary amines thereof. These sizing agents may be used alone or in combination of two or more. The content of the other additives is not particularly limited as long as it does not impair the effect of the present invention. It is preferred to be 0.02 to 200 parts by weight relative to 100 parts by weight of polyamide (A), more preferably 0.03 to 120 parts by weight, and even more preferably 0.03 to 100 parts by weight. The content of the other additives is not particularly limited as long as it does not impair the effect of the present invention. It is preferred to be 0.02 to 200 parts by weight relative to 100 parts by weight of polyamide (A), and more preferably 0.03 to 100 parts by weight. [2] There are no particular restrictions on the manufacturing method of the polyamide composition. A method that can uniformly mix polyamide (A), organic heat stabilizer (B), and the above-mentioned additives that can be used as needed is preferred. Mixing is generally preferred by melt mixing using a single-spindle extruder, a twin-spindle extruder, a kneader, a Bainbury mixer, etc. Melt mixing conditions are not particularly limited. For example, a method of melt mixing for about 1 to 30 minutes at a temperature range about 10 to 50°C higher than the melting point of polyamide can be cited. [3] Properties of the Polyamide Composition The polyamide composition described above preferably has a flexural strength of 100 MPa or more, and more preferably 150 MPa or more. Furthermore, the flexural modulus is preferably 2 GPa or more, and more preferably 5 GPa or more. With the flexural strength and flexural modulus within the above ranges, it becomes easy to obtain a polyamide composition with excellent heat resistance and mechanical properties. The flexural strength and flexural modulus of the polyamide composition can be determined by performing a bending test after the polyamide composition is injection molded into a 4 mm thick test piece, and more specifically, by the method described in the examples. [4] As one embodiment of this invention, the molded article can be made from the above-mentioned polyamide composition. There are no particular limitations on the manufacturing method of the molded article, and known methods can be used. Furthermore, during molding, additives such as chain elongating agents can be added, and furthermore, heat treatment, electron beam crosslinking, or other treatments can be performed after molding. The molded article of this embodiment can be used as various molded articles of any shape and purpose, such as electrical parts, electronic parts, automotive parts, industrial parts, faucet parts, fibers, films, sheets, household goods, entertainment products, etc. As electrical and electronic components, examples include connectors such as FPC connectors, B2B connectors, card connectors, SMT connectors (coaxial connectors, etc.), and memory card connectors; SMT relays; SMT bobbins; slots such as memory slots and CPU slots; switches such as instruction switches and SMT switches; optical components such as fiber optic components and photosensors; LED components such as LED reflectors; and electronic substrates such as solar cell substrates, LED mounting substrates, flexible printed circuit boards, and resin-molded circuit boards. Examples of automotive parts include: cooling components such as thermostat housings, coolant control valve housings, thermal management module housings, radiator tanks, radiator hoses, water outlets, water inlets, water pump housings, and rear connectors; intake and exhaust system components such as intercooler tanks, intercooler housings, turbine guides, EGR cooler boxes, resonators, throttle bodies, intake manifolds, and tailpipes; fuel system components such as fuel delivery pipes, fuel tanks, quick connectors, canisters, pump modules, fuel lines, oil filters, locking nuts, and seals; structural components such as mount brackets, torque rods, and cylinder heads; drive system components such as bearing retainers, gear tensioners, headlight actuation gears, throttle valve gears, sliding door rollers, and clutch peripheral components; brake system components such as pneumatic brake lines; and wiring harnesses in the engine compartment. Automotive electrical components including harness connectors, motor parts, sensors, ABS cable trays, combination switches, and vehicle switches; sliding door dampers, door mirror supports, door mirror brackets, interior mirror supports, roof rails, engine mounts, air purifier intake pipes, door checkers, plastic chains, signs, clamps, breaker covers, cup holders, airbags, mudguards, spoilers, radiator brackets, radiator grilles, louvers, air scoops, hood humps, rear doors, and fuel injector modules, etc. As industrial components, examples include gas pipes, oilfield extraction pipes, hoses, termite-proof cables (communication cables, access cables, etc.), coating parts for powder coatings (internal coatings for water pipes, etc.), subsea oilfield pipes, pressure-resistant hoses, hydraulic pipes, paint pipes, fuel pump housings or impellers, separators, booster conduits, butterfly valves, conveyor roller bearings, railway sleeper spring seats, outboard motor engine covers, generator engine covers, wind turbine blades, irrigation valves, large opening and closing devices (switches), and monofilaments (extruded yarn) for fishing nets, etc. Examples of water tap components include: housings for water conveyance parts, water storage parts, filter casings, faucet housings, pipe housings, bathroom tap housings (hot and cold water switching valves, water flow switching valves, etc.), sanitary fixture housings, kitchen tap housings, water heater housings, valve components (shut-off ball, slide, cylinder) and valve component housings, toilet stop valve housings, showerhead housings, water heater valve housings, connectors for residential equipment pipelines (underfloor pipelines, etc.), bathroom tap connectors, water pipe connectors, pipe fittings, water meter housings, water meter components (bearings, propellers, pins) and water meters, gas meter housings, distributor housings, valve / pump housings for household appliances, steam-resistant components for steam irons, internal containers for electric kettles, dishwasher components (wash tub, wash nozzles, dishwasher basket), pump housings, and pump components (e.g., turbine rotors). Wheels, impellers, housings of water supply systems (hot water tanks, etc.), housings of heating systems, housings of cooling systems, water flow regulating valves, pressure reducing valves, release valves, solenoid valves, three-way valves, thermal valves, hot water temperature sensors, water flow sensors, adapters for bathtubs, etc. Examples of fibers include airbag fabric, heat-resistant filters, reinforcing fibers, brush bristles, fishing lines, tire cord fabric, artificial turf, blankets, and seat fibers. Examples of thin films and sheets include heat-resistant adhesive tapes such as heat-resistant shielding tapes and industrial tapes; magnetic tape materials such as cassette tapes, digital data storage magnetic tapes, and videotapes; food packaging materials such as bags for sterilized foods, individual packaging for snacks, and packaging for processed meat products; and electronic component packaging materials such as packaging for semiconductor packaging. Examples of household products include valve / pump housings for tea and coffee makers, valve / pump housings for cooking appliances (rice cookers, steamers, etc.), steam-resistant parts for cooking appliances (such as the lid of an electric rice cooker), sliding parts for cooking appliances (such as gears), sliding parts for commercial cooking utensils (such as gears for gear pumps), and steam-resistant parts for commercial cooking utensils (such as pipes for commercial electric rice cookers). Examples of recreational items include insoles for athletic shoes, frames or eyelets for tennis rackets, clubheads or sleeves for golf clubs, spools or rods for fishing tackle, screws for boats, suspensions, gears, saddles, and bottle cages for bicycles. The polyamide composition of this embodiment, due to its excellent formability, heat resistance, and chemical resistance, is suitable as injection-molded components requiring high-temperature properties and chemical resistance, heat-resistant films, various pharmaceutical / liquid delivery pipes, intake pipes, blow-by tubes, and substrates for 3D printers. Furthermore, it is suitable for molded articles requiring high heat resistance and chemical resistance in automotive applications, such as interior and exterior automotive parts, engine compartment parts, cooling system parts, sliding parts, and electrical components. In addition, the polyamide composition of this embodiment can be used to create molded articles requiring heat resistance suitable for surface mount processes. Such molded articles are suitable for use in electrical and electronic components, surface mount connectors, slots, camera modules, power supply components, switches, sensors, capacitor banks, hard disk components, relays, resistors, fuse holders, coil bobbins, IC housings, and other surface mount components. [Examples] Hereinafter, the present invention will be specifically described by way of examples and comparative examples, but the present invention is not limited to such examples. The evaluations in the examples and comparative examples were performed according to the methods shown below. <Polyamide> • Intrinsic Viscosity For the polyamides obtained in the examples and comparative examples, the intrinsic viscosity (dl / g) at a concentration of 0.2 g / dl and a temperature of 30°C was calculated using concentrated sulfuric acid as the solvent by the following formula (Equation 2). η=[ln(t 1 / t 0)] / c (Equation 2) In the above equation, η represents the intrinsic viscosity (dl / g), t 0 indicates the flow time (in seconds) of the solvent (concentrated sulfuric acid), t 1 represents the flow time of the sample solution (seconds), and c represents the concentration of the sample in the sample solution (g / dl) (i.e., 0.2g / dl). • Melting point, crystallization temperature, and glass transition temperature: The melting point, crystallization temperature, and glass transition temperature of the polyamide obtained in the examples and comparative examples were measured using a differential scanning calorimeter (DSC7020) manufactured by Hitachi High Tech Science. The melting point and crystallization temperature were measured according to ISO 11357-3 (2011, 2nd edition). Specifically, under a nitrogen atmosphere, the sample (polyamide) was heated from 30°C to 340°C at a rate of 10°C / min, held at 340°C for 5 minutes to allow the sample to completely melt, cooled to 50°C at a rate of 10°C / min, held at 50°C for 5 minutes, and then heated again to 340°C at a rate of 10°C / min. The peak temperature of the exothermic peak that appeared during cooling was defined as the crystallization temperature, and the peak temperature of the endothermic peak that appeared during reheating was defined as the melting point (°C). The glass transition temperature (°C) was determined according to ISO 11357-2 (2nd edition, 2013). Specifically, under a nitrogen atmosphere, the sample (polyamide) was heated from 30°C to 340°C at a rate of 20°C / min, held at 340°C for 5 minutes to allow complete melting, then cooled to 50°C at a rate of 20°C / min and held at 50°C for 5 minutes. The temperature at which the inflection point occurs when the temperature is raised again to 200°C at a rate of 20°C / min is defined as the glass transition temperature (°C). • The crystallization rate was determined using the following formula (Formula 1) for the polyamides obtained in the examples and comparative examples. Crystallization rate (°C) -1 = 1 / (melting point (°C) - crystallization temperature (°C)) (Equation 1) Furthermore, in Equation 1, "melting point (°C)" and "crystallization temperature (°C)" are values ​​determined by the above method. Also, in Table 1, the unit for crystallization rate is denoted as [unit not specified in °C]. -1 The synonym for "1 / ℃". • Terminal amino group content ([NH 2) The amount of terminal amino groups in the polyamides obtained in the Examples and Comparative Examples was calculated by titrating a solution containing thymol blue (an indicator) dissolved in 30 mL of phenol with 0.01 mol / L hydrochloric acid aqueous solution. In Tables 1-3, the amount of terminal amino groups in the polyamides is expressed as [NH4+]. 2] indicates. • Terminal carboxyl group content ([COOH]): The terminal carboxyl group content of the polyamides obtained in the Examples and Comparative Examples was calculated by titrating a solution containing 0.5 g of polyamide dissolved in 40 mL of cresol using a potentiometric titration apparatus manufactured by Kyoto Electronics Industry Co., Ltd. In Tables 1-3, the terminal carboxyl group content of the polyamide is expressed as [COOH]. <Polyamide Composition> <Preparation of Test Pieces> An injection molding machine (clamping force: 100 tons, screw diameter: φ32 mm) manufactured by Sumitomo Heavy Industries, Ltd. was used for the polyamide compositions obtained in the examples and comparative examples. The barrel temperature was set to be 20-30°C higher than the melting point of polyamide. The polyamide compositions of Examples 1-8, 12, 13 and Comparative Examples 1, 2, 3, 5, 6 were formed at a mold temperature of 140°C. The polyamide compositions of Example 11 and Comparative Example 4 were formed at a mold temperature of 170°C using a T-runner mold. Multi-purpose test piece type A1 (dumbbell-shaped test piece as described in JIS K7139:2009; 4 mm thick, 170 mm in total length, 80 mm in parallel section length, and 10 mm in parallel section width) was produced. • Bending strength and bending modulus were determined using a multi-purpose test piece type A1 (4 mm thick) prepared by the above method, according to ISO 178 (2nd edition 2012), at a test speed of 2 mm / min and a distance between support points of 64 mm, using a universal testing machine (manufactured by INSTRON). • Color stability was assessed by heat-treating multi-purpose test specimens (type A1, 4mm thick) prepared using the above method in a hot air dryer at 150°C for 50 hours. The color change of the treated specimens was visually observed and compared with that before heat treatment. Color stability was evaluated according to the following criteria: • A: No color change. • B: Slight yellowing, but not detrimental to practical use. • C: Obvious yellowing, unsuitable for practical use. • Heat aging resistance was assessed by heat-treating multi-purpose test specimens of type A1 (4 mm thick) prepared using the above method in a hot air dryer at 150°C for 50 hours. The molecular weight of the removed test specimens and the untreated test specimens was measured, and the molecular weight change rate was calculated using the following formula (Formula 3). The heat aging resistance was evaluated based on the calculated molecular weight change rate using the following criteria. "A" and "B" were considered acceptable, and "C" and "D" were considered unacceptable. Furthermore, the molecular weight of the test specimens was measured as described below. Molecular weight change rate (%) = ((molecular weight after heat treatment - molecular weight before heat treatment) / (molecular weight before heat treatment)) × 100 (Formula 3) • A: Molecular weight change rate is less than ±10% • B: Molecular weight change rate is more than ±10% and less than ±20% • C: Molecular weight change rate is more than ±20% and less than ±30% • D: Molecular weight change rate is more than ±30% • Hydrolysis resistance was assessed by immersing a multi-purpose test piece (type A1, 4 mm thick) prepared using the method described above in an antifreeze solution (a 2-fold diluted aqueous solution of Toyota Motor Corporation's "Super Long Life Coolant" (pink)). The heat-resistant container was then placed in a constant temperature bath set to 130°C for 100 hours for the immersion treatment. The molecular weight of the removed test pieces and the untreated test pieces was measured, and the rate of change of molecular weight was calculated using the following formula (Formula 4). Hydrolysis resistance was evaluated from the calculated rate of change of molecular weight using the following criteria. "A" and "B" were considered acceptable, and "C" and "D" were considered unacceptable. Furthermore, the molecular weight of the test pieces was measured as described in the molecular weight determination section below. Molecular weight change rate (%) = ((Molecular weight after impregnation treatment - Molecular weight before impregnation treatment) / (Molecular weight before impregnation treatment)) × 100 (Equation 4) • A: Molecular weight change rate less than ±10% • B: Molecular weight change rate greater than ±10% and less than ±20% • C: Molecular weight change rate greater than ±20% and less than ±30% • D: Molecular weight change rate greater than ±30% • Molecular weight determination: The molecular weight of the above-mentioned multi-purpose test piece type A1 was determined by gel permeation chromatography (GPC) using polymethyl methacrylate as a standard. Specifically, a solution of sodium trifluoroacetate dissolved in HFIP at a ratio of 0.85 g to 1 kg of 1,1,1,3,3,3-hexafluoroisopropanol (HFIP) was used as the precipitate. Using resin conversion, 1.5 mg of the sample (the above-mentioned multi-purpose test piece type A1) was measured and dissolved in 3 mL of the precipitate. The solution was passed through a 0.2 μm membrane filter to prepare the test sample, and the determination was performed under the following conditions. (Test conditions) Apparatus: HLC-8320GPC (manufactured by Tosoh Corporation) Column: Two TSKgel SuperHM-H (manufactured by Tosoh Corporation) columns connected in series. Solution: 10 mg / L sodium trifluoroacetate / HFIP solution; Flow rate: 0.5 mL / min (reference column: 0.25 mL / min); Sample injection volume: 30 μL; Column temperature: 40℃; Standard polymethyl methacrylate: Shodex Standard M-75 manufactured by Showa Denko Corporation, and Polymethlmethacrylate (molecular weight 1010, 535) manufactured by Agilent Technologies, Inc.; Detector: UV (254 nm) detector. • Formability: When producing multi-purpose test piece type A1 (4mm thick) using the above method, a minimum cooling time was set for when the test piece becomes free of observable dents and voids and can be smoothly demolded from the mold. Cases with a cooling time set below 10 seconds were classified as "A", cases exceeding 10 seconds but less than 15 seconds were classified as "B", and cases exceeding 15 seconds were classified as "C". "A" and "B" were deemed acceptable, and "C" was deemed unacceptable. This shows the components used in preparing the polyamide compositions of the examples and comparative examples. <Organic Heat Stabilizer (B)> Phenolic Antioxidant (Sumitomo Chemical Co., Ltd. "GA-80") <Other Additives> • Lubricant "LICOWAX OP" (Clariant Chemicals Co., Ltd.) • Crystallization Nucleating Agent "TALC ML112" (Fuji Talc Industrial Co., Ltd.) • Filler Glass Fiber "CS03JA-FT2A" (Owens Corning Japan Limited Liability Company) • Colorant Carbon Black "#980B" (Mitsubishi Chemical Co., Ltd.) [Example 1] A mixture of 5,400 g terephthalic acid, 5,260 g 2-ethyl-1,7-heptanediamine, 2-propyl-1,6-hexanediamine, and 2-methyl-1,8-octanediamine [4 / 1 / 95 (molar ratio)], 121 g benzoic acid, 10 g (0.1% by mass relative to the total mass of the raw materials) sodium hypophosphite monohydrate, and 4.8 L of distilled water were placed in a 40 L autoclave for nitrogen substitution. After stirring at 150 °C for 30 minutes, the temperature inside the autoclave was raised to 220 °C over 2 hours. At this point, the pressure inside the autoclave was increased to 2 MPa. The pressure was maintained at 2 MPa for 5 hours while heating continued to slowly remove water vapor and allow the reaction to proceed. Next, the pressure was reduced to 1.3 MPa over 30 minutes, and the reaction was allowed to proceed for another hour to obtain the prepolymer. The obtained prepolymer was dried at 100°C under reduced pressure for 12 hours and pulverized to a particle size of less than 2 mm. It was then subjected to solid-state polymerization at 230°C and 13 Pa (0.1 mmHg) for 10 hours to obtain polyamide (A) with a melting point of 282°C. Using the obtained polyamide (A), organic heat stabilizer, lubricant, and nucleating agent in the proportions shown in Table 1, the mixture was fed into the upstream hopper of a twin-screw extruder (manufactured by Plastics Research Institute Co., Ltd., "BTN-32"), melt-mixed, re-extruded, cooled, and cut to obtain granular polyamide composition. [Example 2] Except that the diamine unit was set as a mixture of 2-ethyl-1,7-heptanediamine, 2-propyl-1,6-hexanediamine and 2-methyl-1,8-octanediamine [5.6 / 0.4 / 94 (Morbies)], the same procedure as in Example 1 was followed to prepare polyamide (A) with a melting point of 283°C, and except that the polyamide (A) obtained in this manner was used, the same procedure as in Example 1 was followed to obtain a polyamide composition. [Example 3] Except that the diamine unit was set as a mixture of 2-ethyl-1,7-heptanediamine, 2-propyl-1,6-hexanediamine and 2-methyl-1,8-octanediamine [12 / 3 / 85 (Morby)], a polyamide (A) with a melting point of 262°C was prepared in the same manner as in Example 1, and except that the polyamide (A) obtained in this manner was used, a polyamide composition was obtained in the same manner as in Example 1. [Example 4] Except that the diamine unit was set as a mixture of 2-ethyl-1,7-heptanediamine, 2-propyl-1,6-hexanediamine and 2-methyl-1,8-octanediamine [16 / 4 / 80 (molbi)], a polyamide (A) with a melting point of 258°C was prepared in the same manner as in Example 1, and except that the polyamide (A) obtained in this manner was used, a polyamide composition was obtained in the same manner as in Example 1. [Example 5] Except that the diamine unit was set as a mixture of 2-ethyl-1,7-heptanediamine, 2-propyl-1,6-hexanediamine, 2-methyl-1,8-octanediamine and 1,9-nonanediamine [4 / 1 / 20 / 75 (Morby)], a polyamide (A) with a melting point of 288°C was prepared in the same manner as in Example 1, and except that the polyamide (A) obtained in this manner was used, a polyamide composition was obtained in the same manner as in Example 1. [Example 6] Polyamide (A), organic heat stabilizer (B), lubricant, nucleating agent and colorant obtained in the same procedure as in Example 5 were fed into the upstream hopper of a twin-screw extruder (manufactured by Plastics Research Institute Co., Ltd. "BTN-32") in the proportions shown in Table 1, and fillers were fed into the downstream side feed port of the extruder in the proportions shown in Table 1. The mixture was melt-mixed and extruded, cooled and cut, thereby obtaining a granular polyamide composition. [Example 7] Except that the composition was set to the proportions shown in Table 1, the same procedure as in Example 6 was followed to obtain the polyamide composition. [Example 8] Except that 5,380 g of a mixture of 2-ethyl-1,7-heptanediamine, 2-propyl-1,6-hexanediamine, 2-methyl-1,8-octanediamine and 1,9-nonanediamine [4 / 1 / 20 / 75 (MoRbi)] was used as the diamine unit, a polyamide (A) with a melting point of 288°C was prepared in the same manner as in Example 1, and except that the polyamide (A) obtained in this manner was used, a polyamide composition was obtained in the same manner as in Example 1. [Example 9] Except that 5,540 g of a mixture of 2-ethyl-1,7-heptanediamine, 2-propyl-1,6-hexanediamine, 2-methyl-1,8-octanediamine and 1,9-nonanediamine [4 / 1 / 20 / 75 (MoRbi)] was used as the diamine unit, a polyamide (A) with a melting point of 288°C was prepared in the same manner as in Example 1, and except that the polyamide (A) obtained in this manner was used, a polyamide composition was obtained in the same manner as in Example 1. [Example 10] Polyamide (A) with a melting point of 307°C was prepared in the same manner as in Example 1, except that the diamine unit was set as a mixture of 2-ethyl-1,7-heptanediamine, 2-methyl-1,8-octanediamine and 1,9-nonanediamine [0.5 / 14.5 / 85 (moles)]. Polyamide composition was obtained in the same manner as in Example 1, except that the polyamide (A) obtained in this manner was used. [Comparative Example 1] The polyamide (A) obtained in Example 5 was used directly for evaluation without the addition of organic heat stabilizer (B) and other additives. [Comparative Example 2] Except that the diamine unit was set as 2-methyl-1,8-octanediamine, a polyamide with a melting point of 285°C was prepared in the same manner as in Example 1. In addition to using the polyamide obtained in this manner, a polyamide composition was obtained in the same manner as in Example 1. [Comparative Example 3] Except that the diamine unit was set as a mixture of 2-methyl-1,8-octanediamine and 1,9-nonanediamine [15 / 85 (molar ratio)], a polyamide with a melting point of 306°C was prepared in the same manner as in Example 1. And except that the polyamide obtained in this manner was used, a polyamide composition was obtained in the same manner as in Example 1. [Example 11] Except that the dicarboxylic acid unit was set as 7,027 g of naphthalenedicarboxylic acid and the diamine unit was set as a mixture of 2-ethyl-1,7-heptanediamine, 2-propyl-1,6-hexanediamine, 2-methyl-1,8-octanediamine and 1,9-nonanediamine [4 / 1 / 20 / 75 (MoRbi)], a polyamide (A) with a melting point of 283°C was prepared in the same manner as in Example 1. And except that the polyamide (A) obtained in this manner was used, a polyamide composition was obtained in the same manner as in Example 1. [Comparative Example 4] Except that the dicarboxylic acid unit was set as 7,027 g of naphthalenedicarboxylic acid and the diamine unit was set as a mixture of 2-methyl-1,8-octanediamine and 1,9-nonanediamine [15 / 85 (MoRbi)], a polyamide with a melting point of 294°C was prepared in the same manner as in Example 1. And except that the polyamide obtained in this manner was used, a polyamide composition was obtained in the same manner as in Example 1. [Example 12] Polyamide (A) with a melting point of 292°C was prepared by using 5,600 g of cyclohexanedicarboxylic acid (cis / trans = 79.9 / 20.1) as the dicarboxylic acid unit and a mixture of 2-ethyl-1,7-heptanediamine, 2-propyl-1,6-hexanediamine, 2-methyl-1,8-octanediamine and 1,9-nonanediamine [4 / 1 / 20 / 75 (MoRbi)] as the diamine unit, and by using the polyamide (A) obtained in this manner, a polyamide composition was obtained by using the same manner as in Example 1. [Comparative Example 5] Except that the dicarboxylic acid unit was set to 5,600 g of cyclohexanedicarboxylic acid (cis / trans = 79.9 / 20.1) and the diamine unit was set to a mixture of 2-methyl-1,8-octanediamine and 1,9-nonanediamine [15 / 85 (moles)], a polyamide with a melting point of 301°C was prepared in the same manner as in Example 1. The polyamide composition was obtained in the same manner as in Example 1 except that the polyamide obtained in this manner was used. [Example 13] Except that the diamine unit was set as a mixture of 2-ethyl-1,7-heptanediamine, 2-propyl-1,6-hexanediamine, 2-methyl-1,8-octanediamine and 1,10-decanediamine [4 / 1 / 20 / 75 (Morby)], a polyamide (A) with a melting point of 289°C was prepared in the same manner as in Example 1. And except that the polyamide (A) obtained in this manner was used, a polyamide composition was obtained in the same manner as in Example 1. [Comparative Example 6] Except that the diamine unit was set as a mixture of 2-methyl-1,8-octanediamine and 1,10-decanediamine [20 / 80 (molar ratio)], a polyamide with a melting point of 301°C was prepared in the same manner as in Example 1. And except that the polyamide obtained in this manner was used, a polyamide composition was obtained in the same manner as in Example 1. The composition of the examples and comparative examples and the measurement results thereon are shown in Tables 1 to 3. [Table 1] [Table 2] [Table 3] The abbreviations for the compounds used in Tables 1-3 above and their compound contents are shown in Table 4 below. Furthermore, "(EHDA+PHDA)" in Tables 1-3 indicates the total amount (moles%) of EHDA and PHDA incorporated into the diamine unit. [Table 4] In Tables 1-3, by comparing Examples 1-10 with Comparative Examples 2-3, Example 11 with Comparative Example 4, Example 12 with Comparative Example 5, and Example 13 with Comparative Example 6, it was found that the polyamide (A) used in the polyamide compositions of the examples has a high crystallization rate and a short cooling time during injection molding. It was then found that the formability of the polyamide compositions of the aforementioned comparative examples was inferior to that of the polyamide compositions of the examples. That is, it can be understood that in a polyamide composition containing a common dicarboxylic acid unit, if a specific amount of structural units derived from at least one of 2-ethyl-1,7-heptanediamine and 2-propyl-1,6-hexanediamine is contained as the diamine unit, then due to the high crystallization rate of polyamide (A), it becomes a polyamide composition with high formability and excellent productivity. Furthermore, the polyamide (A) contained in the polyamide composition of the examples contains a specific amount of branched aliphatic diamine units derived from at least one of the structural units of 2-ethyl-1,7-heptanediamine and 2-propyl-1,6-hexanediamine. However, it was found that compared with the polyamide compositions of Comparative Examples 2-6, in which the branched aliphatic diamine units are derived only from the structural units of 2-methyl-1,8-octanediamine with a methyl branch structure, the melting point and glass transition temperature decreased less, and the heat resistance was less likely to decrease. It was then found that the polyamide composition of the examples, by further containing an organic heat stabilizer (B), compared with the polyamide compositions of the comparative examples, has excellent formability, excellent heat aging resistance, and also excellent hydrolysis resistance and color stability. Furthermore, a comparison of the polyamide compositions of Examples 6 and 7 with that of Example 5 clearly demonstrates that, by including fillers, flexural strength and flexural modulus can be significantly improved while maintaining formability, heat aging resistance, hydrolysis resistance, and color stability. [Industrial Applicability] The polyamide composition of this invention exhibits high formability and excellent chemical resistance. Therefore, the polyamide composition of this invention can be used in various molded articles requiring heat resistance and chemical resistance, and is highly useful in improving productivity during the manufacture of molded articles. Furthermore, this application is based on Japanese Patent Application No. 2021-206207, filed on December 20, 2021, the entire contents of which are incorporated herein by reference. none none none.

Claims

1. A polyamide composition comprising a polyamide (A) including a diamine unit (X) and a dicarboxylic acid unit (Y), and an organic heat stabilizer (B), wherein the diamine unit (X) comprises 0.1 mol% or more and less than 36 mol% of a diamine unit (X1), the diamine unit (X1) having 6 to 10 carbon atoms and being a structural unit derived from an aliphatic diamine, wherein the aliphatic diamine is wherein, when any one of the amino groups is bonded to a carbon atom at position 1, an alkyl group having 2 or 3 carbon atoms is bonded to a carbon atom at position 2; the diamine unit (X) further comprises a diamine unit (X2) other than the diamine unit (X1), the diamine unit (X2) being a structural unit derived from at least one of the following groups: linear aliphatic diamines, branched aliphatic diamines other than the aliphatic diamine constituting the diamine unit (X), alicyclic diamines, and aromatic diamines; The diamine unit (X2) is derived from a structural unit selected from at least one of the group consisting of 1,6-hexanediamine, 1,9-nonanediamine, 1,10-decanediamine, 2-methyl-1,5-pentanediamine, and 2-methyl-1,8-octanediamine.

2. The polyamide composition of claim 1, wherein the diamine unit (X1) is derived from the structural unit of the aliphatic diamine having 9 carbon atoms.

3. The polyamide composition of claim 1 or 2, wherein the diamine unit (X1) is derived from a structural unit selected from at least one of the group consisting of 2-ethyl-1,7-heptanediamine and 2-propyl-1,6-hexanediamine.

4. The polyamide composition of claim 1 or 2, wherein the diamine unit (X) comprises 1 to 10 moles of the diamine unit (X1).

5. The polyamide composition of claim 1 or 2, wherein the diamine unit (X2) is derived from at least one structural unit selected from the group consisting of linear aliphatic diamines and branched aliphatic diamines with methyl branches.

6. The polyamide composition of claim 1 or 2, wherein the diamine unit (X2) is derived from the structural unit of a diamine having 6 to 10 carbon atoms.

7. The polyamide composition of claim 1 or 2, wherein the dicarboxylic acid unit (Y) comprises a structural unit derived from at least one of the group consisting of aliphatic dicarboxylic acids, aromatic dicarboxylic acids, and alicyclic dicarboxylic acids.

8. The polyamide composition of claim 1 or 2, wherein the dicarboxylic acid unit (Y) comprises a structural unit derived from at least one of the group consisting of terephthalic acid, cyclohexanedicarboxylic acid, and naphthalenedicarboxylic acid.

9. The polyamide composition of claim 1 or 2 contains, relative to 100 parts by weight of the polyamide (A), 0.05 parts by weight and 5 parts by weight of the organic heat stabilizer (B).

10. The polyamide composition of claim 1 or 2, wherein the organic heat stabilizer (B) is selected from at least one of the group consisting of phenolic heat stabilizers (B1), phosphorus heat stabilizers (B2), sulfur heat stabilizers (B3), and amine heat stabilizers (B4).

11. A polyamide composition comprising a polyamide (A) including a diamine unit (X) and a dicarboxylic acid unit (Y), and an organic heat stabilizer (B), wherein the diamine unit (X) comprises 0.1 mol% or more and less than 36 mol% of a diamine unit (X1), the diamine unit (X1) having 6 to 10 carbon atoms and being a structural unit derived from an aliphatic diamine, wherein the aliphatic diamine has an alkyl group having 2 or 3 carbon atoms bonded at the carbon atom at the 2 position when any one of the amino groups is set to the 1 position; the dicarboxylic acid unit (Y) comprises a structural unit derived from at least one of the group consisting of terephthalic acid, cyclohexanedicarboxylic acid, and naphthalenedicarboxylic acid.

12. The polyamide composition of claim 11, wherein the diamine unit (X1) is derived from the structural unit of the aliphatic diamine having 9 carbon atoms.

13. The polyamide composition of claim 11 or 12, wherein the diamine unit (X1) is derived from a structural unit selected from at least one of the group consisting of 2-ethyl-1,7-heptanediamine and 2-propyl-1,6-hexanediamine.

14. The polyamide composition of claim 11 or 12, wherein the diamine unit (X) comprises 1 to 10 moles of the diamine unit (X1).

15. The polyamide composition of claim 11 or 12, wherein the dicarboxylic acid unit (Y) comprises a structural unit derived from at least one of the group consisting of aliphatic dicarboxylic acids, aromatic dicarboxylic acids, and alicyclic dicarboxylic acids.

16. The polyamide composition of claim 11 or 12 contains, relative to 100 parts by weight of the polyamide (A), 0.05 parts by weight and 5 parts by weight of the organic heat stabilizer (B).

17. The polyamide composition of claim 11 or 12, wherein the organic heat stabilizer (B) is selected from at least one of the group consisting of phenolic heat stabilizers (B1), phosphorus heat stabilizers (B2), sulfur heat stabilizers (B3), and amine heat stabilizers (B4).

18. A molded article comprising a polyamide composition as claimed in any one of claims 1 to 17.

19. The molded article of claim 18 is a film.