JP2023081807A - Polyamide composition, and molded product - Google Patents

Abstract

To provide a polyamide composition giving a molded product excellent in mechanical strength, and visual appearance.SOLUTION: A polyamide composition includes: (A) polyamide, (B) a carbon fiber, and (C) a carbonized resin, where the content of polyamide 66 is 90 mass% or more relative to a mass of the (A) polyamide, the content of a carbon fiber bundle constituted by bundling the (B) carbon fibers is 30 mass% or more relative to a total mass of the polyamide composition, the solidification point is 210°C or higher, the spiral flow value of the polyamide composition in a flat plate spiral metal-mold having a cavity width of 10 mm and a thickness of 2 mm under a condition of a set temperature of 285°C, a metal-mold temperature of 80°C, and an injection pressure of 70 MPa is 48 cm or longer when the content of the carbon fiber bundle is 30 mass% or more and 40 mass% or less, and is 32 cm or longer when the content of the carbon fiber bundle is 40 mass% or more and 50 mass% or less, and the formic acid relative viscosity VR of the polyamide composition is more than 30 and less than 45.SELECTED DRAWING: None

Description

The present invention relates to polyamide compositions and molded articles.

Polyamides represented by polyamide 6 (hereinafter sometimes abbreviated as "PA6") and polyamide 66 (hereinafter sometimes abbreviated as "PA66") are excellent in moldability, mechanical properties or chemical resistance. Because of its excellent properties, it is widely used as a material for various parts of automobiles, electrical and electronic equipment, industrial materials, daily goods, household goods, and the like. In recent years, in order to improve the fuel efficiency of automobiles, there has been a demand for weight reduction of automobiles, so materials having low specific gravity and excellent mechanical properties such as strength and rigidity are desired.

In order to meet such demands, carbon fiber reinforced polyamide compositions have attracted attention as industrially important materials, and various carbon fiber reinforced polyamide compositions have been disclosed (see, for example, Patent Documents 1 to 5). However, it has not yet become widely used as a substitute for metal materials and glass fiber reinforced resin compositions. The reason for this is that the interfacial adhesion between the polyamide and the carbon fiber is poor, and the carbon fiber cannot exert a sufficient reinforcing effect, or the carbon fiber itself requires a large amount of energy during manufacturing, and the manufacturing process is complicated. It is still expensive because it is manufactured.

The use of "recycled carbon fibers" has been proposed to address the problem that carbon fibers themselves require a large amount of energy during production and are produced through complicated production processes (see, for example, Patent Documents 6 to 8). . Patent Literature 6 discloses a recycled carbon fiber having excellent reinforcing effect and excellent dispersibility in a matrix resin. Further, Patent Documents 7 and 8 disclose a recycled carbon fiber resin composition in which a third component is further added to resin and recycled carbon fiber.

JP 2014-145036 A JP 2015-129271 A JP 2015-199959 A WO2013/080820 WO2013/077238 JP 2017-002125 A Japanese Patent Publication No. 2016-540067 WO2007/058298

However, in the prior arts disclosed in Patent Documents 6 to 8, problems such as fluidity at the time of melting and appearance of molded articles in polyamide compositions containing recycled carbon fibers are not recognized.

The present invention has been made in view of the above circumstances, and provides a polyamide composition which is excellent in mechanical strength and appearance when formed into a molded product, and a molded product comprising the polyamide composition.

That is, the present invention includes the following aspects.
(1) A polyamide composition containing (A) polyamide, (B) carbon fiber, and (C) resin carbide,
The (A) polyamide contains 90% by mass or more of polyamide 66 with respect to the mass of the (A) polyamide,
(B) contains 30% by mass or more of carbon fiber bundles formed by bundling carbon fibers with respect to the total mass of the polyamide composition,
The solidification point of the polyamide composition is 210 ° C. or higher,
The spiral flow value of the polyamide composition in a flat spiral mold with a cavity width of 10 mm and a thickness of 2 mm under the conditions of a set temperature of 285 ° C., a mold temperature of 80 ° C., and an injection pressure of 70 MPa is the content of the carbon fiber bundle. is 30% by mass or more and less than 40% by mass with respect to the total mass of the polyamide composition, 48 cm or more, and the content of the carbon fiber bundle is 40% by mass or more and 50% by mass with respect to the total mass of the polyamide composition % or less, is 32 cm or more,
A polyamide composition, wherein the polyamide composition has a formic acid relative viscosity VR of more than 30 and less than 45.
(2) The (C) resin carbide has an area of 20 μm ² or more and 300 μm ² or less when the polyamide composition is dissolved in a hexafluoroisopropanol solvent and observed, and the major axis L relative to the minor axis D The polyamide composition according to (1), which has an aspect ratio L/D of 5 or less.
(3) When the polyamide composition is dissolved in a hexafluoroisopropanol solvent and observed, the area occupation ratio of the (C) resin carbide is 20% or more and 50% or less with respect to the area of the (B) carbon fiber. The polyamide composition according to (1) or (2).
(4) Any one of (1) to (3), wherein the carbon fiber bundle obtained by bundling the (B) carbon fibers has a bulk density of 0.05 g/cm ³ or more and 0.34 g/cm ³ or less. Polyamide composition according to.
(5) The amount of mass reduction of the carbon fiber bundle at 450° C. for 2 hours under an air atmosphere is 5% by mass or more and 20% by mass or less, and the carbon fiber bundle is at 450° C. for 2 hours under an air atmosphere. The polyamide composition according to any one of (1) to (4), wherein the content of chloroform-insoluble matter in the mass reduction amount is 70% by mass or more.
(6) The polyamide composition according to any one of (1) to (5), wherein the carbon atom content in surface elements of the carbon fiber bundle is 80 atom % or more as determined by X-ray photoelectric spectroscopic analysis.
(7) The polyamide composition according to any one of (1) to (6), wherein the (B) carbon fibers are recycled carbon fibers.
(8) (D) further comprising at least one amide compound selected from the group consisting of an amide compound represented by the following general formula (I) and an amide compound represented by the following general formula (II), (1) The polyamide composition according to any one of (7).

(In general formula (I), R ¹¹ and R ¹² are each independently a chain alkyl group having 2 to 22 carbon atoms which may contain at least one selected from the group consisting of a hydroxyl group and an amino group. At least one of R ¹¹ and R ¹² contains at least one selected from the group consisting of a hydroxyl group and an amino group, n11, n12 and n13 are each independently an integer of 4 or more and 12 or less .m11 is an integer of 0 or more and 2 or less.)

(In general formula (II), R ²¹ and R ²² are each independently a chain alkyl group having 2 to 22 carbon atoms which may contain at least one selected from the group consisting of a hydroxyl group and a carboxy group. At least one of R ¹¹ and R ¹² contains at least one selected from the group consisting of a hydroxyl group and a carboxy group, n21, n22 and n23 are each independently an integer of 4 or more and 12 or less .m21 is an integer of 0 or more and 2 or less.)

(9) A molded article obtained by molding the polyamide composition according to any one of (1) to (8).

According to the polyamide composition of the above aspect, it is possible to provide a polyamide composition that is excellent in mechanical strength and appearance when molded. The molded article of the above aspect is obtained by molding the polyamide composition, and is excellent in mechanical strength and appearance.

EMBODIMENT OF THE INVENTION Hereinafter, the form (only henceforth "this embodiment") for implementing this invention is demonstrated in detail.
The following embodiments are examples for explaining the present invention, and are not intended to limit the present invention to the following contents. The present invention can be appropriately modified and implemented within the scope of the gist thereof.

As used herein, the term "polyamide" means a polymer having an amide (--NHCO--) bond in its main chain.

<<Polyamide composition>>
The polyamide composition of the present embodiment includes (A) polyamide, (B) carbon fiber, and (C) resin carbide.

In the polyamide composition of the present embodiment, the (A) polyamide contains 90% by mass or more of polyamide 66 with respect to the mass of the (A) polyamide.
The polyamide composition of the present embodiment contains 30% by mass or more of the (B) carbon fiber bundles formed by bundling carbon fibers with respect to the total mass of the polyamide composition.

The solidification point of the polyamide composition is 210° C. or higher.
The spiral flow value of the polyamide composition in a flat spiral mold with a cavity width of 10 mm and a thickness of 2 mm under the conditions of a set temperature of 285 ° C., a mold temperature of 80 ° C., and an injection pressure of 70 MPa is the content of the carbon fiber bundle. is 30% by mass or more and less than 40% by mass with respect to the total mass of the polyamide composition, 48 cm or more, and the content of the carbon fiber bundle is 40% by mass or more and 50% by mass with respect to the total mass of the polyamide composition % or less, it is 32 cm or more.
The polyamide composition has a formic acid relative viscosity VR of more than 30 and less than 45.

With the polyamide composition of the present embodiment having the above structure, a molded article having excellent mechanical strength and appearance can be obtained.

<Characteristics of Polyamide Composition>
[Solidification point]
The solidification point of the polyamide composition of the present embodiment is 210° C. or higher, preferably 212° C. or higher, more preferably 214° C. or higher, and even more preferably 215° C. or higher. When the solidification point is equal to or higher than the above lower limit, deterioration in physical properties at high temperatures can be suppressed.
On the other hand, the upper limit of the solidification point of the polyamide composition of the present embodiment is not particularly limited. .

The solidification point of the polyamide composition of the present embodiment can be measured using, for example, a differential scanning calorimeter (DSC) (eg DIAMOND-DSC manufactured by PERKIN-ELMER). As specific measurement conditions, the conditions described in Examples described later can be adopted.

[Spiral flow value]
The spiral flow value of the polyamide composition of the present embodiment in a flat spiral mold with a cavity width of 10 mm and a thickness of 2 mm under the conditions of a set temperature of 285 ° C., a mold temperature of 80 ° C., and an injection pressure of 70 MPa is When the content is 30% by mass or more and less than 40% by mass, the length is 48 cm or more, preferably 49 cm or more, and more preferably 50 cm or more. When the spiral flow value is equal to or higher than the lower limit, the polyamide composition has good fluidity.
On the other hand, the upper limit of the spiral flow value under the above conditions is not particularly limited, and can be, for example, 70 cm or less, and can be 60 cm or less.

The spiral flow value of the polyamide composition of the present embodiment in a flat spiral mold with a cavity width of 10 mm and a thickness of 2 mm under the conditions of a set temperature of 285 ° C., a mold temperature of 80 ° C., and an injection pressure of 70 MPa is When the content is 40% by mass or more and 50% by mass or less, the length is 32 cm or more, preferably 33 cm or more, and more preferably 35 cm or more. When the spiral flow value is equal to or higher than the lower limit, the polyamide composition has good fluidity.
On the other hand, the upper limit of the spiral flow value under the above conditions is not particularly limited, and can be, for example, 60 cm or less, and can be 50 cm or less.

The spiral flow value can be obtained by, for example, using an injection molding machine (SE-130D manufactured by Sumitomo Heavy Industries, Ltd.) under the above conditions, performing injection molding with an injection time of 10 seconds and a cooling time of 15 seconds. can be measured.

[Formic acid relative viscosity VR]
The formic acid relative viscosity VR of the polyamide composition of the present embodiment is more than 30 and less than 45, preferably 32 or more and 40 or less. When the formic acid relative viscosity VR is less than or equal to the above upper limit, fluidity can be ensured and a thin molded product can be produced. On the other hand, when the formic acid relative viscosity VR is more than or equal to the above lower limit, it is possible to stabilize the lightening time during molding and to suppress the resin from flowing out from the tip of the nozzle. Furthermore, the mechanical strength can be greatly improved, and the causes of gas generation and mold deposits due to deterioration in thermal stability can be eliminated.

Formic acid relative viscosity VR is obtained by adding the polyamide composition to formic acid and comparing the viscosity of the solubles with the viscosity of the formic acid itself. As specific measurement conditions, the conditions described in Examples described later can be adopted.

Next, each component contained in the polyamide composition of the present embodiment will be described in detail below.

<Constituent>
[(A) Polyamide]
(A) The polyamide is not limited to the following, but for example, (Aa) a polyamide obtained by ring-opening polymerization of a lactam, (Ab) a polyamide obtained by self-condensation of ω-aminocarboxylic acid, (A -c) polyamides obtained by condensing diamines and dicarboxylic acids, copolymers thereof, and the like. (A) Polyamide may be used alone or in combination of two or more.

(Aa) Examples of the lactam used in producing the polyamide include, but are not limited to, pyrrolidone, caprolactam, undecalactam, dodecalactam, and the like.
(Ab) The ω-aminocarboxylic acid used in producing the polyamide is not limited to the following, but includes, for example, ω-amino fatty acids, which are ring-opening compounds of the above lactams with water.
As the lactam or the ω-aminocarboxylic acid, two or more monomers may be used in combination and condensed.

(Ac) Diamines (monomers) used in the production of polyamides are not limited to the following, but examples include linear aliphatic diamines, branched aliphatic diamines, alicyclic diamines, aromatic group diamines and the like.
Linear aliphatic diamines include, but are not limited to, hexamethylenediamine, pentamethylenediamine, and the like.
Examples of branched aliphatic diamines include, but are not limited to, 2-methylpentanediamine, 2-ethylhexamethylenediamine, and the like.
Examples of the alicyclic diamine include, but are not limited to, cyclohexanediamine, cyclopentanediamine, cyclooctanediamine, and the like.
Examples of aromatic diamines include, but are not limited to, p-phenylenediamine, m-phenylenediamine, and the like.
(Ac) The dicarboxylic acid (monomer) used for producing the polyamide is not limited to the following, and examples thereof include aliphatic dicarboxylic acids, alicyclic dicarboxylic acids, and aromatic dicarboxylic acids.
Examples of aliphatic dicarboxylic acids include, but are not limited to, adipic acid, pimelic acid, sebacic acid, and the like.
Examples of the alicyclic dicarboxylic acid include, but are not limited to, cyclohexanedicarboxylic acid.
Examples of aromatic dicarboxylic acids include, but are not limited to, phthalic acid, isophthalic acid, and the like.
The above diamines and dicarboxylic acids as monomers may be condensed either singly or in combination of two or more.

In addition, (A) polyamide may further contain units derived from polyvalent carboxylic acids having a valence of 3 or more, such as trimellitic acid, trimesic acid, and pyromellitic acid, if necessary. The polyvalent carboxylic acid having a valence of 3 or more may be used alone, or two or more of them may be used in combination.

In (A) polyamide, the content of monomer units having an aromatic ring (e.g., aromatic diamine units, aromatic dicarboxylic acid units, etc.) is 10 mol with respect to all monomer units of (A) polyamide. % or less, more preferably 5 mol % or less, even more preferably 1 mol % or less, and particularly preferably 0 mol %. The (A) polyamide having a content of 0 mol % of monomer units having an aromatic ring is an aliphatic polyamide.

(A) Specific examples of polyamides include polyamide 4 (polyα-pyrrolidone), polyamide 6 (polycaproamide), polyamide 11 (polyundecaneamide), polyamide 12 (polydodecanamide), polyamide 46 (polytetra methylene adipamide), polyamide 56 (polypentamethylene adipamide), polyamide 66 (polyhexamethylene adipamide), polyamide 610 (polyhexamethylene sebacamide), polyamide 612 (polyhexamethylene dodecamide), polyamide 6T (polyhexamethylene terephthalamide), polyamide 9T (polynonanemethylene terephthalamide), and copolymerized polyamides containing these as constituents.
Among them, (A) polyamide is preferably polyamide 46 (PA46), polyamide 66 (PA66), polyamide 610 (PA610) or polyamide 612 (PA612). PA66 is excellent in heat resistance, moldability and toughness, and is therefore a suitable material for automobile parts. Long-chain aliphatic polyamides such as PA610 are preferred because of their excellent chemical resistance.

Further, (A) polyamide has, for example, a structure represented by the following general formula (III) (hereinafter abbreviated as "structure (III)"), a structure represented by the following general formula (IV) (hereinafter referred to as " structure (IV)”), a structure represented by the following general formula (V) (hereinafter abbreviated as “structure (V)”), and a structure represented by the following general formula (VI) (hereinafter , abbreviated as “structure (VI)”).

(In general formula (III), n31 and n32 are each independently an integer of 4 or more and 11 or less.)

(In general formula (IV), n41 is an integer of 4 or more and 11 or less. Ar is an arylene group.)

(In general formula (V), n51 is an integer of 4 or more and 11 or less.)

(In general formula (VI), n61 is an integer of 4 or more and 11 or less.)

The arylene group includes, for example, a phenylene group, a naphthylene group, an anthracenylene group, a pyrenediyl group, a fluorenediyl group and the like. Among them, the arylene group is preferably a phenylene group.

Preferred polyamides containing structure (III) include, for example, polyamide 46 (polytetramethylene adipamide), polyamide 66 (polyhexamethylene adipamide), polyamide 610, polyamide 612, and the like.

Preferred polyamides containing structure (IV) include, for example, polyamide 6T (polyhexamethylene terephthalamide), polyamide 9T (polynonamethylene terephthalamide), polyamide 6I (polyhexamethylene isophthalamide), and the like.

Preferred polyamides containing structure (V) include, for example, polyamide MXD6 (polymetaxylylene adipamide), polyamide PXD6 (polyparaxylylene adipamide), polyamide MXD10 (polymetaxylylene sebacamide), polyamide PXD10 ( poly-p-xylylene sebacamide) and the like.

Preferred polyamides containing structure (VI) include, for example, polyamide 4 (polyα-pyrrolidone), polyamide 6 (polycaproamide), polyamide 11 (polyundecaneamide), polyamide 12 (polydodecanamide), and the like.

(Terminal blocking agent)
(A) The terminal of the polyamide may be terminal-blocked with a known terminal-blocking agent.
Such a terminal blocker is also used as a molecular weight modifier when producing a polyamide from the dicarboxylic acid, the diamine, and, if necessary, at least one of the lactam and the aminocarboxylic acid. can be added.

Examples of terminal blocking agents include, but are not limited to, monocarboxylic acids, monoamines, acid anhydrides, monoisocyanates, monoacid halides, monoesters, and monoalcohols. Examples of acid anhydrides include, but are not limited to, phthalic anhydride. These terminal blocking agents may be used alone or in combination of two or more.
Among them, a monocarboxylic acid or a monoamine is preferable as the terminal blocking agent. By blocking the ends of the polyamide with a terminal blocking agent, the polyamide composition tends to be more excellent in thermal stability.

As the monocarboxylic acid that can be used as the terminal blocker, any one having reactivity with the amino group that can be present at the terminal of the polyamide can be used. Specific examples of monocarboxylic acids include, but are not limited to, aliphatic monocarboxylic acids, alicyclic monocarboxylic acids, and aromatic monocarboxylic acids.
Examples of aliphatic monocarboxylic acids include, but are not limited to, formic acid, acetic acid, propionic acid, butyric acid, valeric acid, caproic acid, caprylic acid, lauric acid, tridecylic acid, myristic acid, palmitic acid, stearic acid, pivalic acid, isobutyric acid and the like.
Examples of the alicyclic monocarboxylic acid include, but are not limited to, cyclohexanecarboxylic acid.
Examples of aromatic monocarboxylic acids include, but are not limited to, benzoic acid, toluic acid, α-naphthalenecarboxylic acid, β-naphthalenecarboxylic acid, methylnaphthalenecarboxylic acid, and phenylacetic acid.
These monocarboxylic acids may be used alone or in combination of two or more.

As the monoamine that can be used as the terminal blocking agent, any one having reactivity with the carboxyl group that may be present at the terminal of the polyamide may be used. Specific examples of monoamines include, but are not limited to, aliphatic monoamines, alicyclic monoamines, and aromatic monoamines.
Examples of aliphatic amines include, but are not limited to, methylamine, ethylamine, propylamine, butylamine, hexylamine, octylamine, decylamine, stearylamine, dimethylamine, diethylamine, dipropylamine, dibutylamine. etc.
Examples of the alicyclic amine include, but are not limited to, cyclohexylamine, dicyclohexylamine, and the like.
Examples of aromatic amines include, but are not limited to, aniline, toluidine, diphenylamine, naphthylamine, and the like.
These monoamines may be used alone or in combination of two or more.

Polyamide compositions containing polyamides end-capped with end-capping agents tend to be superior in heat resistance, fluidity, toughness, low water absorption and rigidity.

((A) polyamide content)
The content of the polyamide (A) in the polyamide composition of the present embodiment can be, for example, 40% by mass or more and 99% by mass or less, for example, 45% by mass or more and 90% by mass, relative to the total mass of the polyamide composition. % or less, for example, 50 mass % or more and 80 mass % or less.

In addition, the content of (A) polyamide is preferably 80% by mass or more, more preferably 90% by mass or more, and still more preferably 100% by mass with respect to the total mass of all polyamide resins in the polyamide composition. That is, it is more preferable that (A) polyamide is substantially the entire polyamide resin in the polyamide composition.

Further, the content of polyamide 66 is 90% by mass or more relative to the mass of (A) polyamide in the polyamide composition, preferably 95% by mass or more, more preferably 99% by mass or more, and 100% by mass. preferable. That is, it is more preferable that substantially polyamide 66 is (A) polyamide in the polyamide composition.

((A) Method for producing polyamide)
(A) When producing the polyamide, it is preferable that the amount of the dicarboxylic acid and the amount of the diamine added are approximately the same molar amount. Considering the amount of diamine that escapes to the outside of the reaction system during the polymerization reaction, the molar ratio of the total diamine to the total molar amount of dicarboxylic acid is preferably 0.9 or more and 1.2 or less. , is preferably 0.95 to 1.1, more preferably 0.98 to 1.05.
The method for producing a polyamide is not limited to the following, but for example, a dicarboxylic acid that constitutes a dicarboxylic acid unit, a diamine that constitutes a diamine unit, and, if necessary, a lactam and an amino that constitute a lactam unit. It includes a step of polymerizing at least one of aminocarboxylic acids constituting carboxylic acid units to obtain a polymer.
Moreover, it is preferable that the method for producing a polyamide further includes a step of increasing the degree of polymerization of the polyamide.
In addition, a blocking step of blocking the ends of the obtained polymer with a terminal blocking agent may be included as necessary.

Specific methods for producing polyamides include, for example, various methods exemplified in 1) to 4) below.
1) A method of heating an aqueous solution of a dicarboxylic acid-diamine salt or a mixture of a dicarboxylic acid and a diamine, or a suspension of these water to polymerize while maintaining the molten state (hereinafter referred to as "thermal melt polymerization method" sometimes referred to as).
2) A method of increasing the degree of polymerization of a polyamide obtained by a hot melt polymerization method while maintaining a solid state at a temperature below the melting point (hereinafter sometimes referred to as "hot melt polymerization/solid phase polymerization method").
3) A method of polymerizing a dicarboxylic acid-diamine salt or a mixture of a dicarboxylic acid and a diamine while maintaining the solid state (hereinafter sometimes referred to as "solid phase polymerization method").
4) A method of polymerizing using a dicarboxylic acid halide component and a diamine component equivalent to the dicarboxylic acid (hereinafter sometimes referred to as "solution method").
Among them, as a specific method for producing a polyamide, a production method including a hot melt polymerization method is preferable. Moreover, when producing a polyamide by a hot melt polymerization method, it is preferable to maintain a molten state until the polymerization is completed. As a method of maintaining the molten state, for example, a method of producing under polymerization conditions suitable for the composition of the polyamide can be mentioned. Polymerization conditions include, for example, the conditions shown below. 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 lowered to atmospheric pressure (gauge pressure is 0 kg/cm ² ) over 30 minutes or more to obtain a polyamide having a desired composition.

In the method for producing polyamide, the form of polymerization is not particularly limited, and may be a batch system or a continuous system.
The polymerization apparatus used for the production of polyamide is not particularly limited, and known apparatuses can be used. For example, an autoclave reactor, a tumbler reactor, an extruder reactor such as a kneader, etc. mentioned.

As a method for producing a polyamide, a method for producing a polyamide by a batch-type hot-melt polymerization method will be specifically described below, but the method for producing a polyamide is not limited to this.
First, an aqueous solution containing about 40% by mass or more and 60% by mass or less of polyamide raw material components (dicarboxylic acid, diamine, and, if necessary, at least one of lactam and aminocarboxylic acid) C. or less and a pressure of about 0.035 MPa or more and 0.6 MPa or less (gauge pressure) to concentrate to about 65 mass % or more and 90 mass % or less to obtain a concentrated solution.
The resulting concentrated solution is then transferred to an autoclave and heating is continued until the pressure in the autoclave is about 1.2 MPa to 2.2 MPa (gauge pressure).
After that, in the autoclave, the pressure is maintained at about 1.2 MPa or more and 2.2 MPa or less (gauge pressure) while removing at least one of water and gas components, and when the temperature reaches about 220 ° C. or more and 260 ° C. or less, Reduce the pressure to atmospheric pressure (gauge pressure is 0 MPa).
By reducing the pressure in the autoclave to atmospheric pressure and then reducing the pressure as necessary, water produced as a by-product can be effectively removed.
The autoclave is then pressurized with an inert gas such as nitrogen to extrude the polyamide melt from the autoclave as a strand. The extruded strand is cooled and cut to obtain polyamide pellets.

(Polymer end of polyamide)
(A) Polyamide polymer ends are not particularly limited, but can be classified and defined as follows.
That is, 1) an amino group terminal, 2) a carboxy group terminal, 3) a terminal with a blocking agent, and 4) other terminals.
1) The amino group terminal is a polymer terminal having an amino group ( _--NH2 group) and is derived from the diamine unit of the raw material.
2) The carboxy group terminal is a polymer terminal having a carboxy group (--COOH group), which is derived from the raw material dicarboxylic acid.
3) Terminals formed by a capping agent are terminals formed when a capping agent is added during polymerization. The terminal blocking agent mentioned above is mentioned as a blocking agent.
4) Other terminals are polymer terminals not classified in 1) to 3) above. Specific examples of other terminals include terminals formed by deammonification of amino group terminals, terminals formed by decarboxylation of carboxy group terminals, and the like.

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

2. (A) Polyamide crystallization enthalpy ΔH
(A) The crystallization enthalpy ΔH of the polyamide is preferably 45 J/g or more, more preferably 50 J/g or more, from the viewpoint of mechanical properties, particularly water absorption stiffness and heat stiffness. On the other hand, it is preferably 70 J/g or less in order to secure the amorphous part to which the filler is added.
(A) As an apparatus for measuring the melting point Tm2 and the enthalpy of crystallization ΔH of the polyamide, for example, Diamond-DSC manufactured by PERKIN-ELMER Co., Ltd. may be used.

3. (A) End group amount of polyamide (A) In polyamide, (A) the total amount of terminals expressed as mol equivalents per 1 g of polyamide is 130 μmol equivalents / g or more and 160 μmol equivalents / g or less, 135 μmol equivalents / g or more and 155 μmol equivalents / g or less is preferable.
In addition, the content of amino group terminals is 10 mol % or more and 35 mol % or less, preferably 12 mol % or more and 30 mol % or less, relative to the total amount of the terminals.
When the total amount of the terminals of the polyamide and the content of the amino group terminals are within the above numerical range, (B) an excellent interface is formed with the carbon fiber, and the mechanical strength is improved.
The end of the polyamide can be measured using ¹ H-NMR as described in Examples below.

[(B) Carbon fiber]
(B) Carbon fiber is preferably added in the form of carbon fiber bundles bundled with (C) resin charcoal as a binder during the production of the polyamide composition of the present embodiment.
(B) The carbon fibers may contain new carbon fibers, but from an economic point of view, it is preferable to contain only recycled carbon fibers. The term "recycled carbon fiber" as used herein mainly means carbon fiber recovered from carbon fiber reinforced plastics (CFRP).
In general, "carbon fiber reinforced plastic (CFRP)" means a composite material in which carbon fiber and resin are mixed, and is used as a material for aircraft and automobiles as a composite material that is lighter and stronger than steel. It is

(bulk density)
The bulk density of the carbon fiber bundle is preferably 0.05 g/cm ³ or more and 0.34 g/cm ³ or less, more preferably 0.08 g/cm ³ or more and 0.32 g/cm ³ or less, and 0.10 g/cm ³ or more. 0.30 g/cm ³ or less is more preferable, and 0.10 g/cm ³ or more and 0.20 g/cm ³ or less is particularly preferable.
When the bulk density is within the above numerical range, the spreadability of the carbon fiber bundle is improved. Furthermore, since the content of carbonized resin derived from CFRP in the carbon fiber bundle is reduced, it is possible to further reduce the decrease in the strength of the molded product that can be caused by the carbonized resin mixed into the polyamide composition becoming foreign matter. can.

In order to set the bulk density of the carbon fiber bundle obtained by using (C) resin carbide as a binder and (B) carbon fiber bundled in the above numerical range, for example, CFRP is heated to burn the resin content, and the carbon fiber bundle (recycled carbon fiber) can be used. Specifically, by burning CFRP under appropriate conditions, the thermosetting resin of CFRP can be sufficiently burned and decomposed. Thereby, the bulk density of the carbon fiber bundle can be lowered to the above numerical range. Furthermore, by sufficiently burning the thermosetting resin of CFRP and taking out carbon fiber bundles (recycled carbon fibers), the spreadability of the taken out carbon fiber bundles is improved, and (C) resin charcoal is a polyamide composition. It is possible to reduce the phenomenon that the strength is reduced due to foreign matter inside.

Further, in order to set the bulk density of the carbon fiber bundle within the above numerical range, for example, a method of performing combustion of the thermosetting resin of CFRP in a plurality of times can be used. By performing the combustion of the CFRP thermosetting resin in multiple steps, the CFRP thermosetting resin can be burned until the bulk density of the carbon fiber bundle falls within the above numerical range.

The bulk density of the carbon fiber bundle can be calculated using the average value obtained by putting the carbon fiber bundle into a container so as to have a volume of 100 cm ³ , measuring the mass, and repeating the measurement five times.

(Mass loss and chloroform-insoluble matter at 450°C for 2 hours in an air atmosphere)
In addition, the carbon fiber bundle has a mass reduction amount of 5 mass% or more and 20 mass% or less at 450 ° C. for 2 hours under an air atmosphere, and the mass loss of the carbon fiber bundle at 450 ° C. for 2 hours under an air atmosphere. The content of chloroform-insoluble matter in the amount is preferably 70% by mass or more.

The mass reduction amount of the carbon fiber bundle after 2 hours at 450° C. in an air atmosphere is preferably 5% by mass or more and 20% by mass or less, more preferably 7% by mass or more and 17% by mass or less, and 10% by mass or more and 15% by mass or less. More preferred. (B) The 450 ° C. mass loss of carbon fibers is within the above numerical range, so that the stability of the feed to the extruder during melt-kneading is further improved, while excessive (C) resin carbide ( B) Inhibition of carbon fiber opening and (C) generation of dust during melt-kneading derived from carbonized resin can be further reduced.
Also, the amount of mass reduction of the carbon fiber bundle at 450° C. for 2 hours in the air atmosphere can be adjusted by changing the thermal decomposition temperature and time of the resin in the process of taking out the recycled carbon fiber from CFRP.

In addition, from the viewpoint of improving physical properties by forming an interface with polyamide, the content of the chloroform-insoluble matter in the amount of weight loss of the carbon fiber bundle at 450 ° C. for 2 hours in an air atmosphere is preferably 70% by mass or more, and 80% by mass. % or more is more preferable, and 90% by mass or more is even more preferable. Since the content of the chloroform-insoluble matter in the mass reduction amount of the carbon fiber bundle at 450 ° C. for 2 hours in the air atmosphere is at least the above lower limit, a moderate amount of (C) resin carbide is converted into (B) carbon fiber Since it adheres to the surface of the polyamide, the interfacial adhesion with the polyamide is further improved. Thereby, the mechanical properties of the resulting molded product are further improved. On the other hand, the upper limit of the content of the chloroform-insoluble matter in the mass loss of the carbon fiber bundle at 450° C. for 2 hours in the air atmosphere is not particularly limited, but for example, it can be 100% by mass or less, and 99 masses. % or less.

Here, "the amount of mass reduction at 450 ° C. for 2 hours in an air atmosphere" means the mass decreased when held at 450 ° C. in an air atmosphere for 2 hours, relative to the mass before heating (W1) It can be expressed by the ratio (W3/W1×100) (% by mass) of the weight (W3) that is reduced when held at 450° C. for 2 hours in an air atmosphere. In addition, the mass (W3) that decreased when held at 450 ° C. for 2 hours in an air atmosphere is the mass (W1) before heating, and the mass (W2) when held at 450 ° C. for 2 hours in an air atmosphere. It can be calculated by subtracting.
Further, the amount of mass reduction after 2 hours at 450° C. in an air atmosphere can be measured using, for example, TG-DTA (TG8120 manufactured by Rigaku Denki Co., Ltd.).

In addition, the “chloroform-insoluble matter” referred to here means that the carbon fiber bundle is immersed in a sufficient amount of chloroform, permeated for 3 hours at room temperature, filtered, and then the solid content remaining unfiltered is evaporated from the chloroform. means the resulting solids content. The term "chloroform-soluble matter" means the solid content obtained by immersing carbon fibers in a sufficient amount of chloroform, permeating the carbon fibers at room temperature for 3 hours, filtering, and then evaporating the chloroform from the filtrate.

In addition, the "chloroform-insoluble matter" can be calculated by the following measuring method.
First, using the above method, the mass (W3) that has decreased when the carbon fiber bundle (the mass before heating (W1)) is held at 450° C. for 2 hours in an air atmosphere is calculated. Next, the same amount of carbon fiber bundles as the mass (W1) before heating is immersed in a sufficient amount of chloroform, permeated at room temperature for 3 hours, filtered, and then the filtrate is evaporated to remove the solid content ( Chloroform soluble fraction) is obtained. Next, the mass (W4) of the obtained solid content (chloroform-soluble content) is measured. Next, using the obtained mass (W3) that decreased when held at 450 ° C. for 2 hours under an air atmosphere and the mass (W4) of the chloroform-dissolved portion, the following formula was used to calculate the weight of the 450 ° C. It is possible to calculate the content of chloroform-insoluble matter in the amount of mass loss after 2 hours.

"Content (% by mass) of chloroform-insoluble matter in mass loss at 450°C for 2 hours in an air atmosphere"
= {(mass (W3) decreased when held at 450 ° C. for 2 hours in air atmosphere - chloroform dissolved amount (W4)) / mass decreased when held at 450 ° C. for 2 hours in air atmosphere (W3) }×100

In order to set the mass loss amount of the carbon fiber bundle at 450° C. for 2 hours under the air atmosphere and the content of the chloroform-insoluble matter in the mass loss amount at 450° C. for 2 hours under the air atmosphere within the above numerical range, for example , a method of heating CFRP to burn the resin portion and take out the recycled carbon fiber can be used. By burning CFRP under appropriate conditions, the thermosetting resin of CFRP can be left unburned. Thereby, the amount of mass reduction of the carbon fiber bundle at 450° C. for 2 hours in an air atmosphere can be changed.

In order to keep the amount of mass reduction at 450° C. for 2 hours under the air atmosphere within the above numerical range, for example, a method of performing combustion of the CFRP thermosetting resin in multiple stages can be used. By performing the combustion of the CFRP thermosetting resin in multiple steps, the CFRP thermosetting resin is burned until the mass reduction amount of the carbon fiber bundle at 450 ° C. for 2 hours in the air atmosphere falls within the above numerical range. Can burn.

Also, in the method of heating CFRP to burn the resin content and take out recycled carbon fibers, (C) resin carbide adheres to the surface of the carbon fibers. (C) Since the resin charcoal is insoluble in chloroform, it is possible to obtain a carbon fiber bundle having a chloroform-insoluble content within the above numerical range in the weight loss of the carbon fiber bundle at 450° C. for 2 hours in an air atmosphere.

Alternatively, in order to set the chloroform-insoluble matter in the amount of mass reduction of the carbon fiber bundle at 450° C. for 2 hours in the air atmosphere within the above numerical range, for example, the firing conditions at the time of burning the CFRP thermosetting resin are adjusted. method can be used. By adjusting the firing conditions during combustion of the CFRP thermosetting resin, the CFRP is adjusted so that the chloroform-insoluble portion in the mass reduction amount of the carbon fiber bundle at 450 ° C. for 2 hours in the air atmosphere falls within the above numerical range. of thermosetting resin can be burned.

In the recycled carbon fiber obtained by burning CFRP in this way, the (C) carbonized resin adheres to the surface, and the formation of an interface with the polyamide further improves the mechanical properties of the resulting molded product.

(Carbon atom content in surface elements)
The carbon fiber bundle preferably has a carbon atom content of 80 atom % or more among surface elements as determined by X-ray Photoelectron Spectroscopy (XPS) analysis. When the carbon atom content in the surface elements of the carbon fiber bundle as determined by XPS analysis is equal to or higher than the above lower limit, the spreadability of the carbon fiber bundle is further improved. Furthermore, since the content of carbonized resin derived from CFRP in the carbon fiber is reduced, it is possible to further reduce the phenomenon that the carbonized resin mixed in the polyamide composition becomes a foreign matter and the strength of the molded product is reduced. . On the other hand, the upper limit of the carbon atom content in the surface elements of the carbon fiber bundle by XPS analysis is not particularly limited. can do.

In order to make the carbon atom content in the surface elements of the carbon fiber bundle equal to or higher than the above lower limit, for example, a method of heating CFRP to burn the resin portion and take out the recycled carbon fiber can be used. By burning CFRP under suitable conditions, the surface of the carbon fiber can be sufficiently burned. As a result, the functional groups derived from the thermosetting resin and the sizing agent applied to the carbon fibers before being impregnated with the thermosetting resin can be removed. Therefore, the carbon atom content in the surface elements of the carbon fiber bundle can be further increased. By removing the functional groups derived from the thermosetting resin or the sizing agent applied to the carbon fibers before impregnation with the thermosetting resin, the spreadability of the carbon fiber bundles taken out is improved, and (C) It is possible to further reduce the phenomenon in which the carbonized resin becomes a foreign matter in the polyamide composition and the strength is lowered.

(shape)
(B) The carbon fiber may have a circular cross section or a flat cross section. Examples of such a flattened cross section include, but are not limited to, a rectangular shape, an oval shape close to a rectangle, an elliptical shape, and a cocoon shape with a constricted central portion in the longitudinal direction. Here, the "flatness" in the present specification is a value represented by _dc2 / _dc1 , where _dc2 is the major axis of the fiber cross section and _dc1 is the minor axis of the fiber cross section. say. For example, a perfect circle has an oblateness of about 1.

The (B) carbon fiber in the polyamide composition has a number average fiber diameter (d _C ) of 3 μm or more and 30 μm or less and a weight average fiber length (l _C ) is 100 μm or more and 750 μm or less, and the aspect ratio (l _C /d _C ), which is the ratio of the number average fiber diameter (d _C ) to the weight average fiber length (l _C ), is 10 or more and 100 or less. preferable. The "number average fiber diameter (d _c )" referred to here is the average value of the major diameter (d _c 2 above) of the (B) carbon fiber cross section, and is obtained using the calculation method described later.

Here, "number average fiber diameter (d _C )" and "weight average fiber length (l _C )" in this specification can be obtained by the following methods. First, the polyamide composition is placed in an electric furnace to incinerate the contained organic matter. Arbitrarily select 100 or more carbon fibers from the residue after the treatment, observe with a scanning electron microscope (SEM), measure the fiber diameter (major diameter) of these carbon fibers, and calculate the average value for the number By calculating, the number average fiber diameter (d _C ) can be obtained. In addition, the weight average fiber length (l _C ) is obtained by measuring the fiber length using SEM photographs of the 100 or more carbon fibers taken at a magnification of 1000 and calculating the average value for the weight. be able to.

The number average fiber diameter (d _C ) of the carbon fibers is preferably 3 μm or more and 30 μm or less, more preferably 3 μm or more and 20 μm or less, even more preferably 3 μm or more and 12 μm or less, from the viewpoint of improving the toughness and the surface appearance of the molded product. 9 μm or less is particularly preferable, and 4 μm or more and 6 μm or less is most preferable.
By setting the number average fiber diameter of the carbon fibers to be equal to or less than the above upper limit, it is possible to obtain a polyamide composition having excellent toughness and surface appearance of molded articles. On the other hand, by setting the number-average fiber diameter of the carbon fibers to the above lower limit or more, a polyamide composition having excellent balance between cost and powder handling and physical properties (fluidity, etc.) can be obtained.
Furthermore, by setting the number average fiber diameter of the carbon fibers to 3 μm or more and 9 μm or less, it is possible to obtain a polyamide composition having excellent vibration fatigue properties and slidability.

(Content of carbon fiber bundles)
The content of carbon fiber bundles in the polyamide composition can be, for example, 5% by mass or more and 50% by mass or less, for example, 10% by mass or more and 45% by mass or less, relative to the total mass of the polyamide composition. For example, it can be 20% by mass or more and 45% by mass or less.
The content of the carbon fiber bundles is preferably 50 parts by mass or more and 100 parts by mass or less, more preferably 65 parts by mass or more and 100 parts by mass or less, relative to 100 parts by mass of the (A) polyamide. When the carbon fiber bundle content is within the above range, the amount of chips generated during extrusion processing is reduced, and the pellet shape is maintained well, and the molded product has excellent surface appearance and mechanical strength. The effect is particularly remarkable.

[(C) resin carbide]
(C) Resin carbide is obtained by heat-treating a thermosetting resin. Examples of thermosetting resins include epoxy resins and phenol resins. (C) Resin charcoal is preferably a product obtained by baking a thermosetting resin at 1000 ° C. or less from the viewpoint of dispersibility in the polyamide composition, and the thermosetting resin is preferably 400 ° C. or higher and 600 ° C. C. or less is more preferred, and a product obtained by baking a thermosetting resin at 450.degree. C. to 500.degree. C. is even more preferred.

In the production of the polyamide composition of the present embodiment, from the viewpoint of improving productivity, (C) resin carbide is preferably added to (A) polyamide at the same time as (B) carbon fiber. As described above, the carbon fiber bundle (recycled carbon fiber) taken out by heating CFRP to burn the resin portion is a carbon fiber bundle in which (B) carbon fibers are bundled using (C) resin carbide as a binder. By using this carbon fiber bundle, (B) carbon fiber and (C) resin carbide can be added to (A) polyamide at the same time.

When the polyamide composition of the present embodiment is dissolved in a hexafluoroisopropanol (hereinafter sometimes abbreviated as "HFIP") solvent and observed with a stereoscopic microscope, the area of (C) resin carbide is 20 μm ² or more. It is preferably 300 μm ² or less, and the aspect ratio L/D of the major axis L to the minor axis D is 5 or less.
(C) When the area of the resin carbide is equal to or less than the above upper limit, deterioration of the mechanical properties of the polyamide composition can be more effectively suppressed. On the other hand, when the area of the (C) resin carbide is equal to or greater than the above lower limit, the bundling property of the carbon fibers and the mechanical strength of the polyamide composition can be further improved.
Further, when the aspect ratio L/D of the (C) resin carbide is equal to or less than the above upper limit value, deterioration of the mechanical properties of the polyamide composition can be more effectively suppressed. On the other hand, the lower limit of the aspect ratio L/D of the (C) resin carbide is not particularly limited, but can be, for example, 1 or more.

In the polyamide composition of the present embodiment, the area occupation ratio of the (C) resin carbide when dissolved in an HFIP solvent and observed with a stereoscopic microscope is 20% or more and 50% with respect to the area of the (B) carbon fiber. % or less, more preferably 30% or more and 40% or less.
(C) When the area occupation ratio of the carbonized resin is within the above numerical range, it is possible to improve the bundling property of the carbon fibers and the mechanical properties of the polyamide composition.

(C) The method of calculating the aspect ratio and area of the resin carbide, and (C) the area occupation ratio of the resin carbide, is, for example, an image of a polyamide composition dissolved in an HFIP solvent, which is photographed using a stereoscopic microscope. , a method of processing using image analysis software, and the like. For image analysis software, for example, Azo-kun (manufactured by Asahi Kasei Engineering Co., Ltd.) or the like can be used.

[(D) amide compound]
The amide composition of the present embodiment preferably further contains (D) an amide compound as a fluidity improver in addition to the above components (A) to (C).
(D) As the amide compound, an amide compound represented by the following general formula (I) (hereinafter sometimes referred to as "amide compound (I)"), an amide compound represented by the following general formula (II) ( Hereinafter, it may be referred to as "amide compound (II)") and the like.

(In general formula (I), R ¹¹ and R ¹² are each independently a chain alkyl group having 2 to 22 carbon atoms which may contain at least one selected from the group consisting of a hydroxyl group and an amino group. At least one of R ¹¹ and R ¹² contains at least one selected from the group consisting of a hydroxyl group and an amino group, n11, n12 and n13 are each independently an integer of 4 or more and 12 or less .m11 is an integer of 0 or more and 2 or less.)

(In general formula (II), R ²¹ and R ²² are each independently a chain alkyl group having 2 to 22 carbon atoms which may contain at least one selected from the group consisting of a hydroxyl group and a carboxy group. At least one of R ¹¹ and R ¹² contains at least one selected from the group consisting of a hydroxyl group and a carboxy group, n21, n22 and n23 are each independently an integer of 4 or more and 12 or less .m21 is an integer of 0 or more and 2 or less.)

[R ¹¹ and R ¹² ]
R ¹¹ and R ¹² are each independently a chain alkyl group having 2 or more and 22 or less carbon atoms which may contain at least one selected from the group consisting of a hydroxyl group and an amino group. At least one of R ¹¹ and R ¹² contains at least one selected from the group consisting of a hydroxyl group and an amino group. R ¹¹ and R ¹² may be the same or different. Among them, it is preferable that R ¹¹ and R ¹² are the same because synthesis is easy.

Examples of the chain alkyl group having 2 to 22 carbon atoms and not including at least one selected from the group consisting of a hydroxyl group and an amino group for R ¹¹ and R ¹² include a linear alkyl group having 2 to 22 carbon atoms. , a branched alkyl group having 3 or more and 22 or less carbon atoms.

Linear alkyl groups having 2 to 22 carbon atoms include, for example, ethyl group, n-propyl group, n-butyl group, n-pentyl group, n-hexyl group, n-heptyl group, n-octyl group, n-nonyl group, n-decyl group, n-undecyl group, n-dodecyl group, n-tridecyl group, n-tetradecyl group, n-pentadecyl group, n-hexadecyl group, n-heptadecyl group, n-octadecyl group, n-nonadecyl group, n-icosyl group, n-henicosyl group, n-docosyl group and the like.

Branched alkyl groups having 3 to 22 carbon atoms include, for example, isopropyl group, isobutyl group, sec-butyl group, tert-butyl group, isopentyl group, sec-pentyl group, 3-pentyl group and tert-pentyl group. , isohexyl group, sec-hexyl group, tert-hexyl group, isoheptyl group, sec-heptyl group, tert-heptyl group, isooctyl group, sec-octyl group, tert-octyl group, isononyl group, sec-nonyl group, tert- nonyl group, isodecyl group, sec-decyl group, tert-decyl group, isoundecyl group, sec-undecyl group, tert-undecyl group, isolauryl group, sec-lauryl group, tert-lauryl group, isotridecyl group, sec-tridecyl group, tert-tridecyl group, isotetradecyl group, sec-tetradecyl group, tert-tetradecyl group, isopentadecyl group, sec-pentadecyl group, tert-pentadecyl group, isocetyl group, isohexadecyl group, sec-hexadecyl group, tert- hexadecyl group, isoheptadecyl group, sec-heptadecyl group, tert-heptadecyl group, isostearyl group, isononadecyl group, sec-nonadecyl group, tert-nonadecyl group, isoicosyl group, sec-icosyl group, tert-icosyl group, isoheneicosyl group, sec -henicosyl group, tert-henicosyl group, isodocosyl group, sec-docosyl group, tert-docosyl group and the like.

The chain alkyl group having 2 to 22 carbon atoms containing at least one selected from the group consisting of a hydroxyl group and an amino group for R ¹¹ and R ¹² is at least one selected from the above-described group consisting of a hydroxyl group and an amino group. in which at least one hydrogen atom of a chain alkyl group having 2 to 22 carbon atoms and not containing is substituted with at least one selected from the group consisting of a hydroxyl group and an amino group.

Moreover, as described above, a hydroxyl group and an amino group are substituents in a hydrocarbon group. Among them, it is preferable that the substituent includes a hydroxyl group. By including a hydroxyl group, it is possible to form an amide bond and a hydrogen bond in the polyamide. Thereby, the physical properties (mechanical strength and appearance) of the molded article using the polyamide composition of the present embodiment can be further improved.

A chain alkyl group having 2 to 22 carbon atoms containing at least one selected from the group consisting of a hydroxyl group and an amino group for R ¹¹ and R ¹² has at least one selected from the group consisting of a hydroxyl group and an amino group as a substituent. One seed may be included, or two or more may be included.

Among them, each of R ¹¹ and R ¹² is preferably a chain alkyl group having 2 or more and 22 or less carbon atoms containing a hydroxyl group.

Specifically, preferred R ¹¹ and R ¹² are, for example, a group represented by the following general formula (VII) (hereinafter sometimes abbreviated as “group (VII)”) or represented by the following general formula (VIII) group (hereinafter sometimes abbreviated as “group (VIII)”) and the like.

In general formula (VII), n71 and n72 are each independently an integer of 0 or more and 10 or less. Asterisks indicate binding sites.

In general formula (VIII), n81 is an integer of 0 or more and 10 or less. Asterisks indicate binding sites.

(n71, n72 and n81)
n71, n72 and n81 are each independently an integer of 0 or more and 10 or less. Also, n71 and n72 may be the same or different. n71, n72 and n81 are each independently preferably an integer of 1 or more and 8 or less, and more preferably an integer of 1 or more and 5 or less. When n71, n72 and n81 are within the above ranges, it becomes easier to form hydrogen bonds with the amide bonds in the polyamide, and the physical properties (mechanical strength and appearance) of the molded article using the polyamide composition of the present embodiment are improved. can be improved.

[ ^R21 and ^R22 ]
R ²¹ and R ²² are each independently R ²¹ and R ²² are each independently chain alkyl having 2 to 22 carbon atoms which may contain at least one selected from the group consisting of a hydroxyl group and a carboxy group is the base. At least one of R ¹¹ and R ¹² contains at least one selected from the group consisting of a hydroxyl group and a carboxy group. R ²¹ and R ²² may be the same or different. Among them, it is preferable that R ²¹ and R ²² are the same because synthesis is easy.

The chain alkyl group having ² to ²² carbon atoms and not containing at least one selected from the group consisting of a hydroxyl group and a carboxy group for R ²¹ and R ²² is the same as those exemplified for R 11 and R 12 above. are listed.

The chain alkyl group having 2 to ²² carbon atoms containing at least one selected from the group consisting of a hydroxyl group and a carboxy group for R ²¹ and R ²² is the same as those exemplified for R 11 ^and R 12 above. things are mentioned.

Moreover, as described above, a hydroxyl group and a carboxy group are substituents in a hydrocarbon group. Among them, it is preferable that the substituent includes a hydroxyl group. By including a hydroxyl group, it is possible to form an amide bond and a hydrogen bond in the polyamide. Thereby, the physical properties (mechanical strength and appearance) of the molded article using the polyamide composition of the present embodiment can be further improved.

The chain alkyl group having 2 to 22 carbon atoms containing at least one selected from the group consisting of a hydroxyl group and a carboxy group for R ²¹ and R ²² has at least one selected from the group consisting of a hydroxyl group and a carboxy group as a substituent. One seed may be included, or two or more may be included.

Among them, each of R ²¹ and R ²² is preferably a chain alkyl group having 2 or more and 22 or less carbon atoms containing a hydroxyl group.

Specific examples of preferred R ²¹ and R ²² include the above group (VII) and the above group (VIII).

[n11, n12, n13, n21, n22 and n23]
n11, n12, n13, n21, n22 and n23 are the repeating numbers of methylene groups. n11, n12, n13, n21, n22 and n23 are each independently an integer of 4 or more and 12 or less.

(A) at least one selected from the group consisting of n31, n32, n41, n51 and n61, which are the repeating numbers of methylene groups in the polyamide; (B) n11, which is the repeating number of methylene groups in the amide compound; The difference from at least one selected from the group consisting of n12, n13, n21, n22 and n23 is preferably 3 or less, more preferably 2 or less, further preferably 1 or less, and 0 is particularly preferred. When the difference is equal to or less than the above upper limit, the compatibility between (A) the polyamide and (B) the amide compound becomes higher, and the impact resistance and the effect of reducing the viscosity when melted become higher.

For example, when the polyamide composition of the present embodiment contains a polyamide obtained from a diamine and a dicarboxylic acid (polyamide having structure (III)) and an amide compound (I), a combination of n31 and n11, n31 and There may be a combination of n12, a combination of n31 and n13, a combination of n32 and n11, and a combination of n32 and n13, and a combination of n32 and n13.

For example, when the polyamide composition of the present embodiment contains a polyamide obtained from a diamine and a dicarboxylic acid (polyamide having structure (III)) and an amide compound (II), a combination of n31 and n21, n31 and There are possible combinations of n22, n31 and n23, n32 and n21, n32 and n22, and n32 and n23.

For example, when the polyamide composition of the present embodiment contains a polyamide obtained from a lactam or an ω-aminocarboxylic acid (a polyamide having structure (VI)) and an amide compound (I), a combination of n61 and n11, There are possible combinations of n61 and n12 and combinations of n61 and n13.

For example, when the polyamide composition of the present embodiment contains a polyamide obtained from a lactam or an ω-aminocarboxylic acid (a polyamide having structure (VI)) and an amide compound (II), a combination of n61 and n21, There are possible combinations of n61 and n22 and combinations of n61 and n23.

For example, the polyamide composition of the present embodiment is a polyamide obtained from a diamine and a dicarboxylic acid (polyamide having structure (III)) and a polyamide obtained from a lactam (polyamide having structure (VI)). and amide compound (I), a combination of n31 and n11, a combination of n31 and n12, a combination of n31 and n13, a combination of n32 and n11, a combination of n32 and n12, a combination of n32 and n13, n61 and n11, a combination of n61 and n12, and a combination of n61 and n13.

For example, when the polyamide composition of the present embodiment contains two or more polyamides or two or more amide compounds, n31, n32, n41, n51 and n61, n11, n12, n13, n21, n22 and There can be multiple combinations with n23.

Above all, it is preferable that the difference in any one of the following (i) to (iv) is within the above range. Moreover, it is particularly preferable that the difference in (i) or (ii) is 0, or the difference in (iii) or (iv) is 1 or less.
(i) at least one selected from the group consisting of n31 and n41 in the (A) polyamide and at least one selected from the group consisting of the n12, n21 and n23 in the (D) amide compound difference;
(ii) at least one selected from the group consisting of the n32 and the n51 in the (A) polyamide, and at least one selected from the group consisting of the n11, the n13 and the n22 in the (D) amide compound; difference;
(iii) the difference between the n61, which is the repeating number of methylene groups in the (A) polyamide, and at least one selected from the group consisting of the n11, the n13, and the n22 in the (D) amide compound;
(iv) the difference between the n61 in the (A) polyamide and at least one selected from the group consisting of the n12, the n21 and n23 in the (D) amide compound

[m21 and m21]
m11 and m21 are the repeating numbers of the units in parentheses. Each of m11 and m21 is an integer of 0 or more and 2 or less. Among them, m11 and m21 are each preferably 0 because of ease of synthesis and good compatibility with polyamide.

Preferred amide compounds (I) include, for example, N,N'-butylenebis-11-hydroxyarachidonic acid amide, N,N'-hexamethylenebis-11-hydroxyarachidonic acid amide, N,N'-tetramethylene Bis(3-hydroxy)propionic acid amide, N,N'-hexamethylenebis(3-hydroxy)propionic acid amide, N,N'-butylenebis-8-hydroxycapric acid amide, N,N'-hexamethylenebis- 8-hydroxycapric acid amide, N,N'-butylenebis-10-hydroxylauric acid amide, N,N'-hexamethylenebis-10-hydroxylauric acid amide, N,N'-hexamethylenebis-8-hydroxycaprine acid amide, N,N'-butylenebis-10-hydroxylauric acid amide, N,N'-hexamethylenebis-10-hydroxylauric acid amide, N,N'-butylenebis-11-hydroxymyristic acid amide, N,N '-Hexamethylenebis-11-hydroxymyristic acid amide, N,N'-butylenebis-16-hydroxypalmitic acid amide, N,N'-hexamethylenebis-16-hydroxypalmitic acid amide, N,N'-butylenebis- 12-hydroxystearic acid amide, N,N'-hexamethylenebis-12-hydroxystearic acid amide, N,N'-butylenebis-2-hydroxyarachidic acid amide, N,N'-hexamethylenebis-2-hydroxy arachidamide, N,N'-butylenebis-2-hydroxybehenamide, N,N'-hexamethylenebis-2-hydroxybehenamide, N,N'-butylenebis-2-hydroxylignoceramide, N,N'-hexamethylenebis-2-hydroxylignoceramide, N,N'-butylenebis-12-hydroxyoleic acid amide, N,N'-hexamethylenebis-12-hydroxyoleic acid amide, N,N '-butylenebis-11-hydroxylinoleic acid amide, N,N'-hexamethylenebis-11-hydroxylinoleic acid amide and the like.

Preferred amide compounds (II) include, for example, N,N'-bis(2-hydroxyethyl)succinamide and N,N'-bis(2-hydroxyethyl)adipamide.

These compounds are merely examples of preferred amide compound (I) and amide compound (II), and preferred amide compound (I) and amide compound (II) are not limited to these.

[Method for producing (D) amide compound]
The amide compound contained in the polyamide composition of the present embodiment can be produced by, for example, a method of reacting hydroxyalkylamine and dibasic acid, a method of reacting hydroxyalkylamine and dibasic acid ester, and a method of reacting hydroxycarboxylic acid and diamine. It can be produced by a reaction method, a method of reacting a lactone and a diamine, a method of reacting an aminocarboxylic acid and a dibasic acid, a method of reacting an aminocarboxylic acid and a diamine, and the like.

(D) A commercial product can also be used as an amide compound. Commercially available (D) amide compounds include, for example, Struktol TR-063A (manufactured by Struktol America).

[Content of (D) amide compound]
In the polyamide composition of the present embodiment, the content of the (D) amide compound is preferably 0.50 parts by mass or more and 3.00 parts by mass or less with respect to 100 parts by mass of the (A) polyamide. It is more preferably 60 parts by mass or more and 2.00 parts by mass or less. When the content of the (D) amide compound is at least the above lower limit, fluidity, mechanical properties, and surface appearance tend to be better.

[(E) Lubricant]
The polyamide composition of the present embodiment may further contain (E) a lubricant in addition to the above components (A) to (D).

(E) Lubricants include, but are not limited to, higher fatty acids, higher fatty acid metal salts, higher fatty acid esters, higher fatty acid amides, and the like.

(higher fatty acid)
Examples of higher fatty acids include linear or branched saturated or unsaturated aliphatic monocarboxylic acids having 8 to 40 carbon atoms.
Examples of linear or branched saturated or unsaturated aliphatic monocarboxylic acids having 8 to 40 carbon atoms include lauric acid, palmitic acid, stearic acid, behenic acid and montanic acid.
Examples of branched-chain saturated aliphatic monocarboxylic acids having 8 to 40 carbon atoms include isopalmitic acid and isostearic acid.
Examples of linear unsaturated aliphatic monocarboxylic acids having 8 to 40 carbon atoms include oleic acid and erucic acid.
Examples of branched unsaturated aliphatic monocarboxylic acids having 8 to 40 carbon atoms include isoleic acid.
These higher fatty acids may be used alone or in combination of two or more.
Among them, stearic acid or montanic acid is preferable as the higher fatty acid.

(Higher fatty acid metal salt)
A higher fatty acid metal salt is a metal salt of a higher fatty acid.
Examples of the metal elements of the metal salt include Group 1 elements, Group 2 elements and Group 3 elements of the periodic table of elements, zinc, aluminum and the like.
Group 1 elements of the periodic table of elements include, for example, sodium and potassium.
Group 2 elements of the periodic table of elements include, for example, calcium and magnesium.
Group 3 elements of the periodic table of elements include, for example, scandium and yttrium.
Among them, the metal element is preferably an element of Groups 1 and 2 of the periodic table or aluminum, and more preferably sodium, potassium, calcium, magnesium or aluminum.

Specific examples of higher fatty acid metal salts include calcium stearate, aluminum stearate, zinc stearate, magnesium stearate, calcium montanate, sodium montanate, and calcium palmitate.
These higher fatty acid metal salts may be used alone or in combination of two or more.
Among them, as the higher fatty acid metal salt, a metal salt of montanic acid or a metal salt of stearic acid is preferable.

(higher fatty acid ester)
Higher fatty acid esters are esters of higher fatty acids and alcohols.
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 preferable.
Examples of aliphatic alcohols 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.
These higher fatty acid esters may be used alone or in combination of two or more.

(higher fatty acid amide)
A higher fatty acid amide is an amide compound of a higher fatty acid.
Examples of higher fatty acid amides include stearic acid amide, oleic acid amide, erucic acid amide, ethylenebisstearylamide, ethylenebisoleylamide, N-stearyl stearic acid amide, N-stearyl erucic acid amide and the like.
These higher fatty acid amides may be used alone or in combination of two or more.

The content of the lubricant in the polyamide composition is preferably 0.001 parts by mass or more and 1 part by mass or less with respect to 100 parts by mass of the polyamide (A) in the polyamide composition, and 0.03 parts by mass or more and 0.5 Part by mass or less is more preferable.
When the content of the lubricant is within the above numerical range, it is possible to obtain a polyamide composition which is more excellent in releasability and plasticization time stability, and which is also more excellent in toughness. In addition, it is possible to more effectively prevent an extreme reduction in the molecular weight of the polyamide due to scission of the molecular chain.

[(F) Thermal stabilizer]
The polyamide composition of the present embodiment may further contain (F) a heat stabilizer in addition to the above components (A) to (D).

Examples of heat stabilizers include, but are not limited to, phenol-based heat stabilizers, phosphorus-based heat stabilizers, amine-based heat stabilizers, Groups 3, 4 and 11-14 of the periodic table of the elements. metal salts of the elements, halides of alkali metals and alkaline earth metals, and the like.

(Phenolic heat stabilizer)
Phenolic heat stabilizers include, but are not limited to, hindered phenol compounds. Hindered phenol compounds have the property of imparting excellent heat resistance and light resistance to resins such as polyamides and fibers.

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

When using a phenolic heat stabilizer, the content of the phenolic heat stabilizer in the polyamide composition is preferably 0.01% by mass or more and 1% by mass or less with respect to the total mass of the polyamide composition, and 0.1 % by mass or more and 1 mass % or less is more preferable.
When the content of the phenolic heat stabilizer is within the above numerical range, the heat aging resistance of the polyamide composition can be further improved and the amount of gas generated can be further reduced.

(Phosphorus heat stabilizer)
Examples of phosphorus-based heat stabilizers include, but are not limited to, pentaerythritol-type phosphite compounds, trioctylphosphite, trilaurylphosphite, tridecylphosphite, octyldiphenylphosphite, trisisodecyl Phosphite, phenyldiisodecylphosphite, phenyldi(tridecyl)phosphite, diphenylisooctylphosphite, diphenylisodecylphosphite, diphenyl(tridecyl)phosphite, triphenylphosphite, tris(nonylphenyl)phosphite, tris(2 ,4-di-tert-butylphenyl)phosphite, tris(2,4-di-tert-butyl-5-methylphenyl)phosphite, tris(butoxyethyl)phosphite, 4,4'-butylidene-bis( 3-methyl-6-tert-butylphenyl-tetra-tridecyl)diphosphite, tetra(C12-C15 mixed alkyl)-4,4'-isopropylidene diphenyl diphosphite, 4,4'-isopropylidenebis(2-tert -butylphenyl)-di(nonylphenyl)phosphite, tris(biphenyl)phosphite, tetra(tridecyl)-1,1,3-tris(2-methyl-5-tert-butyl-4-hydroxyphenyl)butanedi Phosphites, tetra(tridecyl)-4,4'-butylidenebis(3-methyl-6-tert-butylphenyl) diphosphite, tetra(C1-C15 mixed alkyl)-4,4'-isopropylidene diphenyl diphosphite, tris (mono, dimixed nonylphenyl) phosphite, 4,4′-isopropylidenebis(2-tert-butylphenyl)-di(nonylphenyl)phosphite, 9,10-di-hydro-9-oxa-9- Oxa-10-phosphaphenanthrene-10-oxide, tris(3,5-di-tert-butyl-4-hydroxyphenyl)phosphite, hydrogenated-4,4′-isopropylidene diphenyl polyphosphite, bis (Octylphenyl)-bis(4,4′-butylidenebis(3-methyl-6-tert-butylphenyl))-1,6-hexanol diphosphite, hexatridecyl-1,1,3-tris(2- methyl-4-hydroxy-5-tert-butylphenyl)diphosphite, tris(4,4'-isopropylidenebis(2-tert-butylphenyl))phosphite, tris(1,3-stearoyloxyisopropyl)phosphite, 2,2-methylenebis(4,6-di-tert-butylphenyl)octylphosphite, 2,2-methylenebis(3-methyl-4,6-di-tert-butylphenyl)2-ethylhexylphosphite, tetrakis ( 2,4-di-tert-butyl-5-methylphenyl)-4,4'-biphenylene diphosphite, tetrakis(2,4-di-tert-butylphenyl)-4,4'-biphenylene diphosphite, etc. is mentioned.
These phosphorus-based heat stabilizers may be used alone or in combination of two or more.
Among them, as the phosphorus-based heat stabilizer, pentaerythritol type phosphite compound and tris(2,4-di-tert-butylphenyl ) one or more selected from the group consisting of phosphites.

Examples of pentaerythritol-type phosphite compounds include, but are not limited to, 2,6-di-tert-butyl-4-methylphenyl-phenyl-pentaerythritol diphosphite, 2,6-di- tert-butyl-4-methylphenyl-methyl-pentaerythritol diphosphite, 2,6-di-tert-butyl-4-methylphenyl-2-ethylhexyl-pentaerythritol diphosphite, 2,6-di-tert- Butyl-4-methylphenyl-isodecyl-pentaerythritol diphosphite, 2,6-di-tert-butyl-4-methylphenyl-lauryl-pentaerythritol diphosphite, 2,6-di-tert-butyl-4- Methylphenyl-isotridecyl-pentaerythritol diphosphite, 2,6-di-tert-butyl-4-methylphenyl-stearyl pentaerythritol diphosphite, 2,6-di-tert-butyl-4-methylphenyl cyclohexyl -pentaerythritol diphosphite, 2,6-di-tert-butyl-4-methylphenyl-benzyl-pentaerythritol diphosphite, 2,6-di-tert-butyl-4-methylphenyl ethyl cellosolve-pentaerythritol Diphosphite, 2,6-di-tert-butyl-4-methylphenyl-butylcarbitol-pentaerythritol diphosphite, 2,6-di-tert-butyl-4-methylphenyl-octylphenyl-pentaerythritol diphosphite phosphites, 2,6-di-tert-butyl-4-methylphenyl-nonylphenyl pentaerythritol diphosphite, bis(2,6-di-tert-butyl-4-methylphenyl) pentaerythritol diphosphite, Bis(2,6-di-tert-butyl-4-ethylphenyl) pentaerythritol diphosphite, 2,6-di-tert-butyl-4-methylphenyl-2,6-di-tert-butylphenyl-penta Erythritol diphosphite, 2,6-di-tert-butyl-4-methylphenyl-2,4-di-tert-butylphenyl-pentaerythritol diphosphite, 2,6-di-tert-butyl-4-methyl Phenyl-2,4-di-tert-octylphenyl-pentaerythritol diphosphite, 2,6-di-tert-butyl-4-methylphenyl-2-cyclohexylphenyl-pentaerythritol diphosphite, 2,6-di -tert-amyl-4-methylphenyl-phenyl pentaerythritol diphosphite, bis(2,6-di-tert-amyl-4-methylphenyl)pentaerythritol diphosphite, bis(2,6-di -tert-octyl-4-methylphenyl)pentaerythritol diphosphite and the like.
These pentaerythritol-type phosphite compounds may be used alone or in combination of two or more.

Among them, as the pentaerythritol-type phosphite compound, bis(2,6-di-tert-butyl-4-methylphenyl)pentaerythritol diphosphite, bis(2 ,6-di-tert-butyl-4-ethylphenyl)pentaerythritol diphosphite, bis(2,6-di-tert-amyl-4-methylphenyl)pentaerythritol diphosphite, and bis(2,6 -di-tert-octyl-4-methylphenyl)pentaerythritol diphosphite, preferably one or more selected from the group consisting of bis(2,6-di-tert-butyl-4-methylphenyl)pentaerythritol diphosphite Fight is more preferred.

When using a phosphorus-based heat stabilizer, the content of the phosphorus-based heat stabilizer in the polyamide composition is preferably 0.01% by mass or more and 1% by mass or less with respect to the total mass of the polyamide composition, and 0.1 % by mass or more and 1 mass % or less is more preferable.
When the content of the phosphorus-based heat stabilizer is within the above numerical range, the heat aging resistance of the polyamide composition can be further improved, and the amount of gas generated can be further reduced.

(Amine heat stabilizer)
Examples of amine heat stabilizers include, but are not limited to, 4-acetoxy-2,2,6,6-tetramethylpiperidine, 4-stearoyloxy-2,2,6,6-tetra methylpiperidine, 4-acryloyloxy-2,2,6,6-tetramethylpiperidine, 4-(phenylacetoxy)-2,2,6,6-tetramethylpiperidine, 4-benzoyloxy-2,2,6, 6-tetramethylpiperidine, 4-methoxy-2,2,6,6-tetramethylpiperidine, 4-stearyloxy-2,2,6,6-tetramethylpiperidine, 4-cyclohexyloxy-2,2,6, 6-tetramethylpiperidine, 4-benzyloxy-2,2,6,6-tetramethylpiperidine, 4-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-tetra methyl-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-piperidyl tolylene-2,4-dicarbamate, bis ( 2,2,6,6-tetramethyl-4-piperidyl)-hexamethylene-1,6-dicarbamate, tris(2,2,6,6-tetramethyl-4-piperidyl)-benzene-1,3, 5-tricarboxylate, tris(2,2,6,6-tetramethyl-4-piperidyl)-benzene-1,3,4-tricarboxylate, 1-[2-{3-(3,5-di -tert-butyl-4-hydroxyphenyl)propionyloxy}butyl]-4-[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionyloxy]2,2,6,6-tetramethyl Piperidine, 1,2,3,4-butanetetracarboxylic acid and 1,2,2,6,6-pentamethyl-4-piperidinol and β,β,β',β'-tetramethyl-3,9-[2 ,4,8,10-tetraoxaspiro(5,5)undecane]condensates with diethanol.
These amine heat stabilizers may be used alone or in combination of two or more.

When using an amine-based heat stabilizer, the content of the amine-based heat stabilizer in the polyamide composition is preferably 0.01% by mass or more and 1% by mass or less with respect to the total mass of the polyamide composition, and 0.1 % by mass or more and 1 mass % or less is more preferable.
When the content of the amine-based heat stabilizer is within the above numerical range, the heat aging resistance of the polyamide composition can be further improved, and the amount of gas generated can be further reduced.

(Metal salts of elements of Groups 3, 4 and 11 to 14 of the Periodic Table of Elements)
The metal salts of elements belonging to Groups 3, 4 and 11 to 14 of the Periodic Table are not particularly limited as long as they are salts of metals belonging to these groups.
Among them, copper salts are preferable from the viewpoint of further improving the heat aging resistance of the polyamide composition. 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, stearic acid Copper, a copper complex salt in which copper is coordinated to a chelating agent, and the like can be mentioned.
Examples of copper halides include copper iodide, cuprous bromide, cupric bromide, and cuprous chloride.
Chelating agents include, for example, 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 one or more selected from the group consisting of copper iodide, cuprous bromide, cupric bromide, cuprous chloride and copper acetate, and consists of copper iodide and copper acetate. One or more selected from the group is more preferable. When the preferred copper salts listed above are used, the heat aging resistance is excellent, and the metal corrosion of the screw and cylinder during extrusion (hereinafter sometimes simply referred to as "metal corrosion") is more effectively suppressed. A polyamide composition is obtained.

When a copper salt is used as a heat stabilizer, the content of the copper salt in the polyamide composition is preferably 0.01% by mass or more and 0.60% by mass or less, relative to the total mass of the polyamide (A). 02% by mass or more and 0.40% by mass or less is more preferable.

When the content of the copper salt is within the above numerical range, the heat aging resistance of the polyamide composition can be further improved, and copper deposition and metal corrosion can be more effectively suppressed.

In addition, the content concentration of the copper element derived from the above copper salt is, from the viewpoint of improving the heat aging resistance of the polyamide composition, (A) polyamide 10 ⁶ parts by mass (1 million parts by mass), 10 parts by mass 2000 mass parts or less is preferable, 30 mass parts or more and 1500 mass parts or less is more preferable, and 50 mass parts or more and 500 mass parts or less is still more preferable.

(halides of alkali metals and alkaline earth metals)
Halides of alkali metals and alkaline earth metals 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 two or more of them may be used in combination.
Among them, the halides of alkali metals and alkaline earth metals are preferably one or more selected from the group consisting of potassium iodide and potassium bromide from the viewpoint of improving heat aging resistance and suppressing metal corrosion. Potassium is more preferred.

When alkali metal and alkaline earth metal halides are used, the content of alkali metal and alkaline earth metal halides in the polyamide composition is (A) 0.05 parts by mass with respect to 100 parts by mass of polyamide 20 parts by mass or less is preferable, and 0.2 parts by mass or more and 10 parts by mass or less is more preferable.
When the content of the alkali metal and alkaline earth metal halides is within the above numerical range, the heat aging resistance of the polyamide composition is further improved, and copper precipitation and metal corrosion can be more effectively suppressed. can.

The heat stabilizer components described above may be used alone or in combination of two or more.
Among them, the heat stabilizer is preferably a mixture of a copper salt and an alkali metal or alkaline earth metal halide from the viewpoint of further improving the heat aging resistance of the polyamide composition.

The content ratio of the copper salt and the alkali metal and alkaline earth metal halides is preferably 2/1 or more and 40/1 or less, and 5/1 or more and 30/1 in terms of the molar ratio of halogen to copper (halogen/copper). 1 or less is more preferable.
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.
Further, when the molar ratio of halogen to copper (halogen/copper) is equal to or higher than the above lower limit, precipitation of copper and metal corrosion can be more effectively suppressed. On the other hand, when the molar ratio of halogen to copper (halogen/copper) is equal to or less than the above upper limit, corrosion of the screw of the molding machine can be prevented more effectively without substantially impairing the mechanical properties (toughness, etc.).

[(G) Other resins]
The polyamide composition of the present embodiment may further contain (G) other resins in addition to the above components (A) to (D).

Examples of other resins include, but are not limited to, polyesters, liquid crystal polyesters, polyphenylene sulfides, polycarbonates, polyarylates, phenolic resins, and epoxy resins.

(polyester)
Examples of polyester include, but are not limited to, polybutylene terephthalate, polytrimethylene terephthalate, polyethylene terephthalate, and polyethylene naphthalate.

The content of other resins in the polyamide composition is preferably 50 parts by mass or less, more preferably 30 parts by mass or less, and even more preferably 10 parts by mass or less with respect to 100 parts by mass of the polyamide (A) in the polyamide composition. , 5 parts by mass or less is particularly preferred.
When the content of the other resin in the polyamide composition is within the above numerical range, the polyamide composition can be made more excellent in heat resistance and releasability.

[(H) Other additives]
In addition to the above components (A) to (D), the polyamide composition of the present embodiment contains (H) other additives commonly used in polyamides, as long as the effects of the polyamide composition are not impaired. can also be included. (H) Other additives include, for example, colorants such as pigments and dyes (including colored masterbatches), flame retardants, fibrillating agents, fluorescent bleaching agents, plasticizers, antioxidants, ultraviolet absorbers, and electrifying agents. Inhibitors, fluidity improvers, spreading agents, elastomers and the like can be mentioned.

The content of other additives in the polyamide composition varies depending on the type and the application of the polyamide composition, and is not particularly limited as long as it does not impair the effects of the polyamide composition.

<Method for producing polyamide composition>
As a method for producing the polyamide composition of the present embodiment, if it is a production method including a step of melt-kneading raw material components including the above (A) polyamide, the above (B) carbon fiber, and the above (C) resin carbide, It is not particularly limited.
In the melt-kneading step, for example, when the raw material components are melt-kneaded by an extruder, the set temperature of the extruder is preferably the melting point (Tm2) of the polyamide (A) + 30°C or less.
In the method for producing a polyamide composition of the present embodiment, (C) resin charcoal is preferably added to (A) polyamide at the same time as (B) carbon fiber, and (B) carbon fiber is added to (C) resin charcoal. is added to (A) polyamide in the form of carbon fiber bundles modified as a binder. This further improves the productivity of the polyamide composition.

(A) Examples of the method of melt-kneading raw material components containing polyamide include the following methods (1) and (2).
(1) A method of mixing (A) polyamide and other raw materials using a tumbler, a Henschel mixer, etc., and supplying the mixture to a melt-kneader for kneading.
(2) A method of blending other raw materials from a side feeder into (A) polyamide which has been melted by a single-screw or twin-screw extruder.

As for the method of supplying the components constituting the polyamide composition to the melt kneader, all the components may be supplied to the same supply port at once, or the components may be supplied from different supply ports.

The melt-kneading temperature is preferably about 250° C. or higher and 350° C. or lower in terms of resin temperature.
The melt-kneading time is preferably about 0.25 minutes or more and 5 minutes or less.
The apparatus for melt-kneading is not particularly limited, and known apparatuses such as single-screw or twin-screw extruders, Banbury mixers, mixing rolls, and other melt-kneaders can be used.

The blending amount of each component when producing the polyamide composition of the present embodiment is the same as the content of each component in the polyamide composition described above.

≪Molded product≫
The molded article of this embodiment is obtained by molding the polyamide composition.

The molded article of the present embodiment is obtained by molding the above polyamide composition using a known molding method.
Examples of known molding methods include, but are not limited to, press molding, injection molding, gas-assisted injection molding, welding molding, extrusion molding, blow molding, film molding, blow molding, multi-layer molding, and melt spinning. and other generally known plastic molding methods.

<Application>
Since the molded article of the present embodiment is obtained from the above polyamide composition, it is excellent in surface appearance and mechanical strength. Therefore, the molded article of the present embodiment can be used as various parts such as automobile parts, electric and electronic parts, home appliance parts, OA (Office Automation) equipment parts, mobile equipment parts, industrial equipment parts, daily necessities and household goods, It can be suitably used for extrusion applications and the like. Among others, the molded article of the present embodiment is suitably used as automobile parts, electrical and electronic parts, household appliance parts, OA equipment parts, or portable equipment parts.

Examples of automobile parts include, but are not limited to, air intake system parts, cooling system parts, fuel system parts, interior parts, exterior parts, electrical parts, and the like.

Automotive air intake system parts are not particularly limited, but include, for example, air intake manifolds, intercooler inlets, exhaust pipe covers, inner bushes, bearing retainers, engine mounts, engine head covers, resonators, throttle bodies, and the like.
Automotive cooling system parts include, but are not limited to, chain covers, thermostat housings, outlet pipes, radiator tanks, alternators, and delivery pipes.
Automobile fuel system parts include, but are not limited to, fuel delivery pipes, gasoline tank cases, and the like.
Examples of automotive interior parts include, but are not limited to, instrument panels, console boxes, glove boxes, steering wheels, and trims.
Examples of automotive exterior parts include, but are not limited to, moldings, lamp housings, front grilles, mudguards, side bumpers, door mirror stays, roof rails, and the like.
Examples of automotive electrical components include, but are not limited to, connectors, wire harness connectors, motor components, lamp sockets, sensor vehicle switches, and combination switches.

Examples of electrical and electronic components include, but are not limited to, connectors, reflectors for light emitting devices, switches, relays, printed wiring boards, electronic component housings, outlets, noise filters, coil bobbins, motor end caps, and the like.
Reflectors for light-emitting devices include optical semiconductors such as light-emitting diodes (LEDs), laser diodes (LDs), and semiconductor packages such as photodiodes, charge-coupled devices (CCDs), and complementary metal-oxide semiconductors (CMOS). Can be widely used for

Examples of mobile device parts include, but are not limited to, casings and structures of mobile phones, smart phones, personal computers, mobile game devices, digital cameras, and the like.

Examples of industrial equipment parts include, but are not limited to, gears, cams, insulating blocks, valves, electric tool parts, agricultural equipment parts, engine covers, and the like.

Examples of everyday items and household items include, but are not limited to, buttons, food containers, office furniture, and the like.

Extrusion applications are not particularly limited, but are used for films, sheets, filaments, tubes, rods, hollow molded articles, and the like.

Among these various uses, the molded article of the present embodiment is particularly suitable for exterior structural materials. Exterior structural materials are mechanical parts or structural parts that require molded product surface workability (eg, texturing processability, high surface glossiness, etc.) and relatively high strength and rigidity.
Specific examples of exterior structural materials include OA equipment field products, automobile parts, electrical field products, and other field products.
Examples of OA equipment field items include furniture items such as desk legs, chair legs, seats, cabins, and wagon parts, laptop computer housings, and the like.
Automobile parts include, for example, door mirror stays, wheel rims, wheel caps, wipers, motor fans, seat lock parts, gears, lamp housings, wheel rims, wheel spokes, saddles, saddle posts, handles, stands, cargo beds, etc. .
Electrical field products include, for example, pulleys, gears, hot air fan housings, and the like.
Other field products include, for example, valve housings, nails, screws, bolts, bolt nuts, and the like.

Moreover, since the molded article of the present embodiment has an excellent surface appearance, it is also preferably used as a molded article having a coating film formed on the surface of the molded article.
The method of forming the coating film is not particularly limited as long as it is a known method. For example, coating such as a spray method and an electrostatic coating method can be used.
Moreover, the paint used for coating is not particularly limited as long as it is a known one, and for example, a melamine-crosslinking type polyester polyol resin paint, an acrylic urethane paint, or the like can be used.
Among them, the molded article of the present embodiment is excellent in mechanical strength, toughness, heat resistance, and vibration fatigue resistance, so it is more suitable as a component material for automobiles. , gears, and bearings. Moreover, since it is excellent in mechanical strength, toughness and heat resistance, it is more suitable as a material for electrical and electronic parts.

EXAMPLES 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.
In the examples, 1 kg/cm ² means 0.098 MPa.

<Constituent>
Hereinafter, (A) polyamide, (A') polyamide, (B) carbon fiber and (C) resin carbide used in Examples and Comparative Examples will be described.

[(A) Polyamide]
A-1: Polyamide 66 (formic acid relative viscosity: 44)
A-2: Polyamide 66 (formic acid relative viscosity: 35)

[Carbon fiber bundle containing (B) carbon fiber and (C) resin carbide]
BC-1: Carbon fiber bundle (recycled carbon fiber) containing (B) carbon fiber and (C) resin carbide (average fiber length of carbon fiber bundle: 3 mm, bulk density of carbon fiber bundle: 0.15 g/cm ³ , Mass loss of carbon fiber bundle at 450 ° C. for 2 hours in air atmosphere: 13 mass%, Chloroform-insoluble matter in mass loss of carbon fiber bundle at 450 ° C. for 2 hours in air atmosphere: 99 mass%, Carbon content in surface elements of carbon fiber bundle: 90 atom%)

[(B) Carbon fiber]
B-1: New carbon fiber (manufactured by Toho Tenax Co., Ltd., trade name “HTC413”) (bulk density: 0.4 g/cm ³ , weight loss after 2 hours at 450°C in air: 3% by mass, air Chloroform-insoluble matter in mass loss at 450 ° C. for 2 hours under atmosphere: 1 mass%, carbon content in surface elements: 73 atom%)

[(D) amide compound]
D-1: Struktol TR-063A (manufactured by Struktol America)

<Physical properties and evaluation>
Using each polyamide composition and each molded article obtained in Examples and Comparative Examples, various physical properties were measured and evaluated by the following methods.

[Physical properties 1]
(solidification point)
The solidification point (Tc) of each polyamide composition obtained in Examples, Comparative Examples and Reference Examples was measured by cutting out a sample of about 10 mg and using DIAMOND-DSC manufactured by PERKIN-ELMER. The measurement conditions were as follows.
The initial temperature was set at 50°C, and the temperature was raised to 300°C at a rate of 20°C/min. The temperature was held at 300°C for 3 minutes, and then the temperature was lowered to 50°C at a rate of 20°C/min. Under the above conditions, the solidification point when the temperature was lowered was defined as Tc.

[Physical properties 2]
(Spiral flow value (SFD))
The spiral flow value (SFD) of each polyamide composition obtained in Examples, Comparative Examples and Reference Examples was determined by injection molding under the following conditions and measuring the flow length (cm).
(Measurement condition)
Injection molding machine: "SE-130D" manufactured by Sumitomo Heavy Industries, Ltd.
Mold for measurement: flat spiral mold with internal groove width (cavity) of 10 mm and thickness of 2 mm Mold temperature: 80°C
Set temperature: 285°C
Injection pressure: 70 MPa (injection speed is controlled by pressure at Max setting)
Injection time: 10 seconds Cooling time: 15 seconds

[Physical properties 3]
(Formic acid relative viscosity VR)
Formic acid relative viscosity VR is a solution (soluble matter) obtained by adding (A) polyamide, and each polyamide composition obtained in Examples, Comparative Examples and Reference Examples to formic acid and compares the viscosity of formic acid itself. obtained by doing Specifically, it was carried out according to ASTM-D789. More specifically, using a solution of 8.4% by mass of (A) polyamide or each polyamide composition in 90% by mass formic acid (10% by mass of water), formic acid relative viscosity VR at 25 ° C. was measured.

[Physical properties 4]
(Area occupying ratio of (C) resin carbide to (B) carbon fiber)
10 mg of polyamide composition pellets obtained in Examples, Comparative Examples, and Reference Examples were dissolved in 2 mL of HFIP solvent, and the resulting solution was photographed with a stereoscopic microscope. Analysis software (manufactured by Asahi Kasei Engineering Co., Ltd., product name "Azo-kun") was used for processing. From the treatment results, the amount of (C) resin carbide having an area of 20 μm ² or more and 300 μm ² or less and an aspect ratio l / d of 5 or less, and the area occupation ratio of (C) resin carbide to (B) carbon fiber asked for

[Production of molded product 1 (molded piece of multi-purpose test piece A type)]
For the pellets of each polyamide composition obtained in Examples, Comparative Examples and Reference Examples, using an injection molding machine (PS-40E, manufactured by Nissei Plastic Industry Co., Ltd.), in accordance with ISO 3167, Multi-purpose test piece type A was molded into a molded piece of Specific molding conditions were as follows: injection + holding pressure time: 25 seconds, cooling time: 15 seconds, mold temperature: 80°C, molten resin temperature: melting peak temperature (Tm2) on the high temperature side of polyamide + 20°C.

[Evaluation 1]
(Tensile strength and tensile elongation)
A tensile test was performed at a tensile speed of 50 mm/min under a temperature condition of 23° C. according to ISO527 using a molded piece of multi-purpose test piece A type, and the tensile yield stress was measured and taken as the tensile strength. Also, the elongation at breakage was defined as the tensile elongation.

[Evaluation 2]
(Charpy impact strength with notch)
A molded piece of multi-purpose test piece A type was cut to obtain a test piece of length 80 mm×width 10 mm×thickness 4 mm. Using the test piece, the notched Charpy impact strength (kJ/m ² ) was measured according to ISO179.

[Production of molded product 2 (flat plate molded piece)]
Pellets of each polyamide composition obtained in Examples, Comparative Examples, and Reference Examples were set to the following conditions using an injection molding machine (NEX50III-5EG, manufactured by Nissei Plastic Industry Co., Ltd.), and the filling time was 1. The injection pressure and injection speed were appropriately adjusted so that the injection time was in the range of 0.6±0.1 seconds, and a flat plate molded piece (6 cm×9 cm, thickness 2 mm) was produced.

(manufacturing conditions)
Cooling time: 25 seconds Screw rotation speed: 200 rpm
Mold temperature: Tanδ peak temperature +5°C
Cylinder temperature: (Tm2 + 10) ° C or higher (Tm2 + 30) ° C or lower

[Evaluation 3]
(Surface appearance)
The central portion of the obtained flat plate molded piece was visually confirmed. The evaluation results of the surface appearance were as follows.

(Evaluation criteria)
5: Excellent surface smoothness and gloss 4: Some parts are slightly uneven on the surface and excellent gloss 3: Some parts are uneven on the surface and the gloss is uneven 2: The surface is not entirely smooth , Almost no gloss 1: The surface is rough overall and has no gloss

<Production of Polyamide Composition>
[Examples 1-5, Comparative Examples 1-4 and Reference Examples 1-2]
(Production of Polyamide Compositions PA-a1 to PA-a5, PA-b1 to PA-b4, and PA-c1 to PA-c2) The (A) polyamide, the (BC) carbon fiber bundle, or the (B) carbon Each polyamide composition was produced by the following method using the fiber and the above (D) amide compound in the types and proportions shown in Tables 1 and 2 below.
The polyamides A-1 and A-2 were dried in a nitrogen stream to adjust the moisture content to about 0.2% by mass, and then used as raw materials for the polyamide composition.

A twin-screw extruder (ZSK-26MC, manufactured by Coperion GmbH (Germany)) was used as an apparatus for producing the polyamide composition.
The twin-screw extruder has an upstream feed port on the first barrel from the upstream side of the extruder, a downstream first feed port on the sixth barrel, and a downstream second feed port on the ninth barrel. had In the twin-screw extruder, the extruder length (l _x )/screw diameter (d _x ) was 48 and the number of barrels was 12.
In the twin-screw extruder, the temperature from the upstream supply port to the die was set at 295° C., the screw rotation speed was set at 250 rpm, and the discharge rate was set at 25 kg/hour.

As a specific manufacturing method using the above-described manufacturing apparatus, the (A) polyamide is supplied from the upstream supply port of the twin-screw extruder under the manufacturing conditions shown below, and the first supply downstream of the twin-screw extruder. (BC) carbon fiber bundles or (B) carbon fibers and optionally (D) an amide compound are supplied from the mouth, and the melt-kneaded product extruded from the die head is cooled in a strand and pelletized to obtain each polyamide composition. I got a pellet of stuff. The obtained polyamide composition pellets were dried in a nitrogen stream to reduce the water content in the polyamide composition to 500 ppm or less.

(manufacturing conditions)
Cooling time: 25 seconds Screw rotation speed: 300 rpm
Mold temperature: 80°C
Cylinder temperature: 290°C

Tables 1 and 2 below show various evaluation results of each polyamide composition obtained in Examples and Comparative Examples and each molded article produced using the polyamide composition.

From Tables 1 and 2, (A) polyamide, (B) carbon fiber and (C) resin carbide are included, the content of polyamide 66 and the content of (B) carbon fiber are within specific ranges, and , the solidification point, spiral flow value and formic acid relative viscosity are within specific ranges, polyamide compositions PA-a1 to PA-a6 (Examples 1 to 6) selected from the group consisting of spiral flow value and formic acid relative viscosity Both the mechanical strength and the appearance when formed into a molded product were superior to the polyamide compositions PA-b1 to PA-b4 (Comparative Examples 1 to 4), in which at least one of them was outside the specific range.
Also, (A) comparison of polyamide compositions PA-a1 and PA-a2 with different types of polyamide (Examples 1 and 2), and PA-a4 and PA-a5 (Examples 4 and 5), formic acid relative It was observed that the use of polyamide (A) having a lower viscosity tended to result in better mechanical strength when formed into a molded product.
In addition, in comparison of polyamide compositions PA-a1 and PA-a3 (Examples 1 and 3) having different contents of (D) amide compound, the higher the content of (D) amide compound, the more the molded article Tensile strength, tensile elongation and appearance tend to be better, while (D) the less the content of the amide compound, the more excellent the notched Charpy impact strength when made into a molded product. rice field.
Further, in comparison of the polyamide compositions PA-a3 and PA-a4 (Examples 3 and 4) having different blending ratios of (A) polyamide and (BC) carbon fiber bundles, the blending ratio of (BC) carbon fiber bundles was small. Indeed, there was a tendency for the mechanical strength and appearance of the molded article to be more excellent.

In addition, in the above polyamide compositions PA-a1 to PA-a6 (Examples 1 to 6), the same level as polyamide compositions PA-c1 to PA-c2 using new carbon fibers (Reference Examples 1 to 2) A good appearance was achieved.

According to the polyamide composition of the present embodiment, it is possible to provide a polyamide composition that is excellent in mechanical strength and appearance when molded. The molded article of the present embodiment is formed by molding the polyamide composition and has excellent mechanical strength and appearance. etc., it can be suitably used as a molding material for various parts.

Claims (9)

A polyamide composition comprising (A) polyamide, (B) carbon fiber, and (C) resin carbide,
The (A) polyamide contains 90% by mass or more of polyamide 66 with respect to the mass of the (A) polyamide,
(B) contains 30% by mass or more of carbon fiber bundles formed by bundling carbon fibers with respect to the total mass of the polyamide composition,
The solidification point of the polyamide composition is 210 ° C. or higher,
The spiral flow value of the polyamide composition in a flat spiral mold with a cavity width of 10 mm and a thickness of 2 mm under the conditions of a set temperature of 285 ° C., a mold temperature of 80 ° C., and an injection pressure of 70 MPa is the content of the carbon fiber bundle. is 30% by mass or more and less than 40% by mass with respect to the total mass of the polyamide composition, 48 cm or more, and the content of the carbon fiber bundle is 40% by mass or more and 50% by mass with respect to the total mass of the polyamide composition % or less, is 32 cm or more,
A polyamide composition, wherein the polyamide composition has a formic acid relative viscosity VR of more than 30 and less than 45. The (C) resin carbide has an area of 20 μm ² or more and 300 μm ² or less when the polyamide composition is dissolved in a hexafluoroisopropanol solvent and observed, and the aspect ratio L of the major axis L to the minor axis D 2. The polyamide composition of claim 1, wherein /D is 5 or less. When the polyamide composition is dissolved in a hexafluoroisopropanol solvent and observed, the area occupation ratio of the (C) resin carbide is 20% or more and 50% or less with respect to the area of the (B) carbon fiber. 3. A polyamide composition according to claim 1 or 2. The polyamide composition according to any one of claims 1 to 3, wherein the (B) carbon fiber bundle obtained by bundling carbon fibers has a bulk density of 0.05 g/cm ³ or more and 0.34 g/cm ³ or less. thing. The amount of mass loss of the carbon fiber bundle after 2 hours at 450°C in an air atmosphere is 5 mass% or more and 20 mass% or less, and the amount of mass loss of the carbon fiber bundle after 2 hours at 450°C in an air atmosphere. The polyamide composition according to any one of claims 1 to 4, wherein the content of chloroform-insoluble matter therein is 70% by mass or more. The polyamide composition according to any one of claims 1 to 5, wherein the carbon atom content in the surface elements of the carbon fiber bundle is 80 atom% or more as determined by X-ray photoelectric spectroscopic analysis. The polyamide composition according to any one of claims 1 to 6, wherein the (B) carbon fibers are recycled carbon fibers. (D) Further comprising at least one amide compound selected from the group consisting of an amide compound represented by the following general formula (I) and an amide compound represented by the following general formula (II). A polyamide composition according to any one of the preceding claims.

(In general formula (I), R ¹¹ and R ¹² are each independently a chain alkyl group having 2 to 22 carbon atoms which may contain at least one selected from the group consisting of a hydroxyl group and an amino group. At least one of R ¹¹ and R ¹² contains at least one selected from the group consisting of a hydroxyl group and an amino group, n11, n12 and n13 are each independently an integer of 4 or more and 12 or less .m11 is an integer of 0 or more and 2 or less.)

(In general formula (II), R ²¹ and R ²² are each independently a chain alkyl group having 2 to 22 carbon atoms which may contain at least one selected from the group consisting of a hydroxyl group and a carboxy group. At least one of R ¹¹ and R ¹² contains at least one selected from the group consisting of a hydroxyl group and a carboxy group, n21, n22 and n23 are each independently an integer of 4 or more and 12 or less .m21 is an integer of 0 or more and 2 or less.) A molded article obtained by molding the polyamide composition according to any one of claims 1 to 8.