JP2020041163A - Polyamide resin composition and molded body - Google Patents

Abstract

To provide a polyamide resin composition excellent in weather resistance and providing a molded body excellent in appearance and low warpage property.SOLUTION: There is provided a polyamide resin composition containing (A) a polyamide resin, (B) an inorganic filler and (C) carbon black, where at least a part of (A) the polyamide resin is (a1) aromatic polyamide, average primary particle diameter of (C) the carbon black is 20 nm or more and specific surface area/DBP oil absorption amount which is a ratio of specific surface area and DBP oil absorption amount is 1.0 or less.SELECTED DRAWING: None

Description

  The present invention relates to a polyamide resin composition and a molded article obtained by molding the polyamide resin composition.

  Polyamide resins have excellent mechanical properties (mechanical strength, rigidity and impact resistance, etc.), toughness, heat resistance, and chemical resistance. It is used in various industrial fields such as industry.

  However, since polyamide resins are easily oxidized and degraded by heat, ultraviolet rays, and the like, there is a limitation on use under conditions where they are exposed outdoors. Conventionally, as a technique for improving the weather resistance of a polyamide resin, a technique of adding carbon black has been known (for example, see Patent Documents 1, 2, and 3).

JP 2006-519909 A JP 2000-53861 A JP 2001-131408 A

However, it is not yet sufficient for use under conditions where it is exposed outdoors for a longer period of time, and there is a need for a polyamide resin composition having a higher level of weather resistance. Further, for exterior applications of automobiles and the like, better appearance and lower warpage are required.
The present invention has been made in view of the above circumstances, and it is an object of the present invention to provide a polyamide resin composition which is excellent in weather resistance and can provide a molded article having excellent appearance and low warpage.

  The present inventors have conducted intensive studies to solve the above problems, and as a result, have found that a polyamide resin composition containing an aromatic polyamide, an inorganic filler, and a predetermined carbon black can solve the above problems. Thus, the present invention has been completed.

That is, the polyamide resin composition of the present invention,
(A) a polyamide resin;
(B) an inorganic filler;
(C) carbon black,
A polyamide resin composition containing
(A) at least a part of the polyamide resin is (a1) an aromatic polyamide;
(C) The carbon black is characterized in that the average primary particle diameter is 20 nm or more, and the specific surface area / DBP oil absorption, which is the ratio of the specific surface area to the DBP oil absorption, is 1.0 or less.

(A) The proportion of the structural unit having an aromatic structure with respect to 100% by mass of all the structural units constituting the polyamide resin is preferably 5 to 100% by mass.
Here, the structural unit means a unit that forms one —CO—NH— (amide) bond, and when the raw material of the polyamide resin is lactam or ω-aminocarboxylic acid, the structural unit is a single structural unit. In the case of a diamine and a dicarboxylic acid, a pair of diamine and dicarboxylic acid is one constituent unit.

  (A) The polyamide resin contains (a2) an aliphatic polyamide as an optional component, and the ratio of the (a1) aromatic polyamide to 100% by mass of the (A) polyamide resin is 10% by mass or more and 100% by mass or less; The proportion of the polyamide is preferably from 0% by mass to 90% by mass.

  (A1) The aromatic polyamide may include at least one selected from polyamide 4T, polyamide 4I, polyamide 6T, polyamide 6I, polyamide MXD6, polyamide MXD10, polyamide MXD12, polyamide PXD6, polyamide PXD10, and polyamide PXD12 as a component. preferable.

  (A2) The aliphatic polyamide is polyamide 6, polyamide 11, polyamide 12, polyamide 46, polyamide 410, polyamide 412, polyamide 66, polyamide 610, polyamide 612, polyamide 1010, polyamide 1012, and at least one of these as a constituent component. It is preferably at least one kind selected from copolymerized polyamides containing as (a).

(C) The average primary particle diameter of the carbon black is preferably 35 nm or more.
(C) The specific surface area of carbon black is preferably 100 m ² / g or less.
(C) DBP oil absorption amount of carbon black ^is preferably 100 cm 3/100 g or more.

The polyamide resin composition may further contain (D) a copper compound, wherein the (D) copper compound is a copper halide compound, copper thiocyanate, copper nitrate, copper acetate, naphthene copper, copper caprate, copper laurate, It is preferably at least one selected from copper stearate, copper acetylacetone, copper oxide (I) and copper oxide (II).
The polyamide resin composition preferably further contains (E) a halide of an alkali metal and / or an alkaline earth metal.

It is preferable that the polyamide resin composition further contains (F) a crystallization retarder.
(F) The crystallization retarder is preferably an azine dye or a phthalocyanine dye.

  The polyamide resin composition may further contain (G) a lubricant, and the (G) lubricant is at least one selected from higher fatty acids, higher fatty acid esters, higher fatty acid amides, higher fatty acid metal salts, and polyolefin waxes. preferable.

  The ratio of the inorganic filler (B) to 100% by mass of the polyamide resin composition is preferably 30% by mass or more and 70% by mass or less.

The molded article of the present invention is obtained by molding the above-mentioned polyamide resin composition of the present invention.
A molded article is more suitable for an automobile exterior part.

  The polyamide resin composition of the present invention comprises (A) a polyamide resin, (B) an inorganic filler, and (C) carbon black, and at least a part of the (A) polyamide resin is (a1) an aromatic polyamide. (C) The average primary particle diameter of carbon black is 20 nm or more, and the ratio of specific surface area to DBP oil absorption [specific surface area / DBP oil absorption] is 1.0 or less. Thus, a molded article excellent in appearance and low warpage can be obtained.

Hereinafter, the present invention will be described in detail.
(Polyamide resin composition)
The polyamide resin composition of the present invention comprises (A) a polyamide resin, (B) an inorganic filler, and (C) carbon black, and at least a part of the (A) polyamide resin is (a1) an aromatic polyamide. (C) The carbon black is characterized in that the average primary particle diameter is 20 nm or more and the ratio of specific surface area to DBP oil absorption [specific surface area / DBP oil absorption] is 1.0 or less.

Hereinafter, each component of the polyamide resin composition will be described in detail.
(A) Polyamide resin (A) Polyamide resin (hereinafter sometimes simply referred to as polyamide resin or component (A)) means a polymer compound having a -CO-NH- (amide) bond in a main chain. I do.
In the present invention, the polyamide resin (A) contains (a1) an aromatic polyamide in at least a part thereof in order to obtain a resin composition having low warpage and improved appearance.

(A1) Aromatic polyamide (a1) Aromatic polyamide (hereinafter sometimes simply referred to as component (a1)) means a polyamide containing an aromatic ring in a molecule, and is used as a raw material constituting a polyamide resin. It is only necessary that a monomer containing an aromatic ring be contained in the molecule. Specifically, an aromatic diamine, a diamine having an aromatic ring, an aromatic dicarboxylic acid, and / or a dicarboxylic acid having an aromatic ring may be contained. When the total amount of the raw material monomers constituting the polyamide is 100 mol%, it is preferable to use 5 mol% or more of a monomer containing an aromatic ring in the molecule at the time of polymerization from the viewpoint of low warpage and improving the appearance. In addition, when calculating all the raw material monomers mentioned here, the diamine and the dicarboxylic acid are calculated assuming that, for example, the diamine is 1 mol and the dicarboxylic acid is 1 mol, and the total monomer is 2 mol.

Examples of the monomer having an aromatic ring in the molecule are not limited to the following. For example, diamines having an aromatic ring such as m-xylylenediamine, p-xylylenediamine, p-phenylenediamine and m-phenylene Examples include aromatic diamines such as diamines, and aromatic dicarboxylic acids such as phthalic acid, isophthalic acid, terephthalic acid, and naphthalenedicarboxylic acid. These diamines having an aromatic ring, aromatic diamines and / or aromatic dicarboxylic acids may be used alone or in combination of two or more.
When an aromatic polyamide is obtained by condensation of a diamine and a dicarboxylic acid, at least one of the diamine and the dicarboxylic acid may be a diamine having an aromatic ring, an aromatic diamine or an aromatic dicarboxylic acid.

  (A1) Specific examples of the aromatic polyamide include, but are not limited to, polyamide 4T (polytetramethylene terephthalamide), polyamide 4I (polytetramethylene isophthalamide), and polyamide 6T (poly). Hexamethylene terephthalamide), polyamide 61 (polyhexamethylene isophthalamide), polyamide MXD6 (poly m-xylylene adipamide), polyamide MXD10 (poly m-xylylene sebacamide), polyamide MXD12 (poly m-xylylene) Dodecamide), polyamide PXD6 (poly p-xylylene adipamide), polyamide PXD10 (poly p-xylylene sebacamide), polyamide PXD12 (poly p-xylylene dodecamide), and polyamides containing these as constituents. Polymerized polyamide It is.

As the constituent components of the copolymer, it is not necessary to have an aromatic ring as a raw material, and lactams, ω-aminocarboxylic acids, aliphatic diamines, alicyclic diamines, aliphatic dicarboxylic acids, and alicyclic rings, which are raw materials for a polyamide resin, are used. A group dicarboxylic acid may be copolymerized.
Lactams include, but are not limited to, pyrrolidone, caprolactam, undecalactam, and dodecalactam.
Examples of the ω-aminocarboxylic acid include, but are not limited to, ω-amino fatty acids, which are ring-opened compounds of the lactams with water. The lactam or the ω-aminocarboxylic acid may be one obtained by condensing two or more monomers in combination.

  Examples of the diamine include, but are not limited to, linear aliphatic diamines such as tetramethylene diamine, pentamethylene diamine, hexamethylene diamine, and decane diamine; 2-methylpentanediamine and 2-ethylhexaamine; Branched aliphatic diamines such as methylene diamine; diamines having an aromatic ring such as p-xylylenediamine and m-xylylenediamine; aromatic diamines such as p-phenylenediamine and m-phenylenediamine; cyclohexanediamine; cyclopentane Alicyclic diamines such as diamine and cyclooctanediamine are exemplified.

  Examples of dicarboxylic acids include, but are not limited to, aliphatic dicarboxylic acids such as adipic acid, pimelic acid, sebacic acid and dodecane diacid, phthalic acid, aromatic dicarboxylic acids such as isophthalic acid and terephthalic acid. An alicyclic dicarboxylic acid such as cyclohexanedicarboxylic acid;

  (A1) Specific examples of the copolymer contained in the aromatic polyamide are not limited to the following. For example, polyamide 66 / 4I, polyamide 66 / 4I / 6, polyamide 6 / 4I, polyamide 66 / 4T, polyamide 66 / 4T / 6, polyamide 6 / 4T, polyamide 66 / 4I / 4T, polyamide 66 / 4I / 4T / 6, polyamide 6 / 4I / 4T, polyamide 610 / 4I, polyamide 610 / 4I / 6, polyamide 610 / 4T, polyamide 610 / 4T / 6, polyamide 610 / 4I / 4T, polyamide 610 / 4I / 4T / 6, polyamide 66 / 6I, polyamide 66 / 6I / 6, polyamide 6 / 6I, polyamide 66 / 6T, polyamide 66 / 6T / 6, polyamide 6 / 6T, polyamide 66 / 6I / 6T, polyamide 6 / 6I / 6T / 6, polyamide 6 / 6I / 6T, polyamide 610 / 6I, polyamide 610 / 6I / 6, polyamide 610 / 6T, polyamide 610 / 6T / 6, polyamide 610 / 6I / 6T, polyamide 610 / 6I / 6T / 6, polyamide 612 / 6I, polyamide 612 / 6I / 6, polyamide 612 / 6T, polyamide 612 / 6T / 6, polyamide 612 / 6I / 6T, polyamide 612 / 6I / 6T / 6, polyamide 6T / 6I, polyamide 6T / 6I / 6, polyamide 6I / 6T, polyamide 6I / 6T / 6, polyamide MXD6 / 6I, polyamide MXD6 / 6T, polyamide MXD6 / 6I / 6T, polyamide MXD6 / 610, polyamide MXD6 / 66, polyamide MXD6 / 610, Polyamide MXD6 / P D6, polyamide PXD6 / 6I, polyamide PXD6 / 6T, polyamide PXD6 / 6I / 6T, polyamide PXD6 / 66, polyamide PXD6 / 610, and the like polyamide PXD6 / 612.

  Among the (a1) aromatic polyamides listed above, from the viewpoint of improving appearance, selected from polyamide 4T, polyamide 4I, polyamide 6T, polyamide 6I, polyamide MXD6, polyamide MXD10, polyamide MXD12, polyamide PXD6, polyamide PXD10, and polyamide PXD12. It is preferably a polyamide containing at least one or more of the above as constituent components. More preferably, polyamide 6T, polyamide 6I, polyamide 6T / 6I, polyamide 6I / 6T, polyamide 6T / 6I / 6, polyamide 6I / 6T / 6, polyamide 66 / 6I, polyamide 66 / 6I / 6, polyamide 6 / 6I , Polyamide 66 / 6I / 6T, polyamide 66 / 6I / 6T / 6, polyamide 6 / 6I / 6T, polyamide 610 / 6I, polyamide 610 / 6I / 6, polyamide 610 / 6T, polyamide 610 / 6T / 6, polyamide 610 / 6I / 6T, polyamide 610 / 6I / 6T / 6, polyamide MXD6, polyamide MXD10, polyamide MXD12, polyamide PXD6, polyamide PXD10, polyamide PXD12, and more preferably polyamide 6I / 6T, polyamide 6T / 6I / 6, LIAMID 6I / 6T / 6, polyamide 66 / 6I, polyamide 66 / 6I / 6, polyamide 6 / 6I, polyamide 66 / 6I / 6T, polyamide 66 / 6I / 6T / 6, polyamide 6 / 6I / 6T, polyamide 6T / 6I, polyamide MXD6, polyamide MXD10, polyamide MXD12, polyamide PXD6, polyamide PXD10, and polyamide PXD12, and particularly preferably polyamide 6T / 6I, polyamide 6I / 6T, polyamide 6T / 6I / 6, polyamide 6I / 6T / 6, PA66 / 6I, PA66 / 6I / 6, PA66 / 6I / 6T, PA66 / 6I / 6T / 6, polyamide MXD6, polyamide MXD10, polyamide MXD12, polyamide PXD6, polyamide PXD10, and polyamide PXD12. One of the above-mentioned aromatic polyamides may be used alone, or two or more may be used in combination.

  The proportion of the (a1) aromatic polyamide relative to 100% by mass of the (A) polyamide resin is preferably from 10% by mass to 100% by mass, from the viewpoint of low warpage and appearance of a molded product, and more preferably 30% by mass. It is at least 100% by mass and more preferably at least 50% by mass and at most 100% by mass.

(A2) Aliphatic polyamide The polyamide resin (A) of the present invention may contain (a2) an aliphatic polyamide (hereinafter sometimes simply referred to as the component (a2)). The (a2) aliphatic polyamide in the present invention means a polyamide containing no aromatic ring in the molecule, and is a polyamide obtained by polymerizing an aliphatic diamine and an aliphatic dicarboxylic acid, or an aliphatic diamine and an alicyclic dicarboxylic acid. Polymerized polyamide, polyamide obtained by polymerizing alicyclic diamine and aliphatic dicarboxylic acid, polyamide obtained by polymerizing alicyclic diamine and alicyclic dicarboxylic acid, aliphatic lactam and / or aliphatic aminocarboxylic acid Polymerized polyamides and their copolymers. Lactam, ω-aminocarboxylic acid, aliphatic diamine, alicyclic diamine, aliphatic dicarboxylic acid, and alicyclic dicarboxylic acid, which are raw materials for the above-described polyamide resin, can be used without any problem.

  Examples of the aliphatic polyamide obtained by condensing a diamine and a dicarboxylic acid include, but are not limited to, polyamide 46 (polytetramethylene adipamide), polyamide 410 (polytetramethylene sebacamide), polyamide 412 (polytetramethylene dodecamide), polyamide 66 (polyhexamethylene adipamide), polyamide 610 (polyhexamethylene sebacamide), polyamide 612 (polyhexamethylene dodecamide), polyamide 1010 (polydecane sebacamide) And polyamide 1012 (polydecanedecamide).

  Examples of the aliphatic polyamide obtained by ring-opening polymerization of lactam include, but are not limited to, polyamide 4 (poly α-pyrrolidone), polyamide 6 (polycaproamide), polyamide 11 (polyundecaneamide), polyamide 12 (polidodecaneamide) and the like.

In addition, these copolymers can be used without any problem. Examples of the copolymer include, but are not limited to, polyamide 46/6, polyamide 410/6, polyamide 412/6, polyamide 66/6, polyamide 610/6, polyamide 612/6, and polyamide 1010/6. , Polyamide 1012/6, polyamide 610/11, polyamide 612/11, polyamide 1010/11, polyamide 1012/11, polyamide 610/12, polyamide 612/12, polyamide 1010/12, polyamide 1012/12, and the like.
As the above-mentioned (a2) aliphatic polyamide, only one kind may be used alone, or two or more kinds may be used in combination.

  Examples of the (a2) aliphatic polyamide in the present invention include polyamide 6, polyamide 11, polyamide 12, polyamide 46, polyamide 410, polyamide 66, polyamide 610, polyamide 612, polyamide 1010, polyamide 1012, and at least one or more selected from these. Is preferred.

  The proportion of the aliphatic polyamide (a2) relative to 100% by mass of the (A) polyamide resin is preferably from 0% by mass to 90% by mass, from the viewpoint of low warpage and appearance of a molded product, and more preferably 0% by mass or more. 70 mass% or less, more preferably 0 mass% or more and 50 mass% or less.

  In the present invention, from the viewpoint of improving appearance, the proportion of the structural unit having an aromatic structure is preferably 5 to 100% by mass with respect to 100% by mass of all the constituent units constituting the polyamide resin. , More preferably 10 to 75% by mass, further preferably 10 to 60% by mass, still more preferably 10 to 50% by mass, particularly preferably 10 to 30% by mass. The constitutional unit referred to herein means a unit constituting one -CO-NH- (amide) bond, and when the raw material is lactam and / or ω-aminocarboxylic acid, the constitutional unit alone becomes a constitutional unit; When obtained by polycondensation of a diamine and a dicarboxylic acid, one structural unit is formed by a pair of the diamine and the dicarboxylic acid.

  For example, in the case of a copolymerized polyamide of polyamide 66 / 6I / 6, there are a structural unit composed of hexamethylenediamine and adipic acid, a structural unit composed of hexamethylenediamine and isophthalic acid, and a structural unit composed of ε-caprolactam. Is a structural unit having an aromatic structure in which the proportion of the structural unit composed of hexamethylenediamine and isophthalic acid is based on 100% by mass of the total. In addition, when it is difficult to specify the structural unit, for example, when it is composed of two or more diamines and two or more dicarboxylic acids, a diamine having an aromatic ring with respect to 100% by mass of all diamines constituting the polyamide resin; The sum of the ratio of the aromatic diamine and the ratio of the dicarboxylic acid having an aromatic ring and / or the aromatic dicarboxylic acid to 100% by mass of the total dicarboxylic acid is the ratio of the structural unit having an aromatic structure.

Further, when the polyamide resin (A) is a mixture of (a1) an aromatic polyamide and a mixture of (a1) an aromatic polyamide and (a2) an aliphatic polyamide, all the constituent units constituting the polyamide resin (A) are 100%. % By mass. For example, in the case of a mixture of polyamide 66 / 6I and polyamide 6, there are structural units composed of hexamethylenediamine and adipic acid, structural units composed of hexamethylenediamine and isophthalic acid, and structural units composed of ε-caprolactam. Is set to 100% by mass. The proportion of the structural unit composed of hexamethylenediamine and isophthalic acid with respect to the total of 100% by mass is the aromatic structural unit.
(A) The method for calculating the aromatic-containing monomer ratio in the polyamide resin is not particularly limited, but can be determined by a nuclear magnetic resonance method (NMR) or the like.

(A) As an end group of the polyamide resin, an amino group or a carboxyl group is generally present.
The ratio of the terminal groups in the polyamide resin is, as amino group concentration / carboxyl group concentration, preferably from 9/1 to 1/9, more preferably from 6/4 to 1/9, and still more preferably from 5/5 to 5/9. 1/9. When the ratio of the terminal groups is within the above range, the mechanical strength of the polyamide resin composition of the present invention can be further improved.

  The concentration of the amino group terminal in the polyamide resin is preferably 10 to 100 μmol / g, more preferably 15 to 80 μmol / g, and still more preferably 30 to 80 μmol / g. When the concentration of the amino group terminal in the polyamide resin is within the above range, the mechanical strength of the polyamide resin composition of the present invention can be further improved.

The concentration of the carboxyl group terminal in the polyamide resin is preferably 20 μmol / g or more, more preferably 50 μmol / g or more, further preferably 50 to 120 μmol / g, and still more preferably 50 to 100 μmol / g. is there. When the concentration of the carboxyl group terminal in the polyamide resin is within the above range, the heat-resistant aging property of the polyamide resin composition of the present invention can be further improved.
Here, the concentration of the amino group terminal and the carboxyl group terminal of the polyamide resin is measured by ¹ H-NMR, and can be determined from the integrated value of the characteristic signal corresponding to each terminal group.

The concentration of the terminal group of the polyamide resin can be appropriately adjusted, and a known method can be used as a method for adjusting the terminal group. Although not limited to the following, for example, a method using a terminal adjuster may be mentioned.
Specifically, the concentration is adjusted by adding at least one selected from the group consisting of a monoamine compound, a diamine compound, a monocarboxylic acid compound, and a dicarboxylic acid compound so that a predetermined terminal concentration is obtained at the time of polymerization of the polyamide resin. can do.
The timing of addition of these components to the polymerization solvent is not particularly limited as long as it fulfills its original function as a terminal adjuster, for example, a method of adding the above-described polyamide resin raw material to the polymerization solvent when adding it. Is mentioned.

Examples of the monoamine compound include, but are not limited to, methylamine, ethylamine, propylamine, butylamine, hexylamine, octylamine, decylamine, stearylamine, dimethylamine, diethylamine, dipropylamine and dibutylamine. Aliphatic monoamines; alicyclic monoamines such as cyclohexylamine and dicyclohexylamine; aromatic monoamines such as aniline, toluidine, diphenylamine and naphthylamine, and any mixtures thereof.
One of these monoamine compounds may be used alone, or two or more thereof may be used in combination.

  In particular, from the viewpoints of reactivity, boiling point, stability of the sealed end, and price, the monoamine compound is selected from the group consisting of butylamine, hexylamine, octylamine, decylamine, stearylamine, cyclohexylamine, and aniline. Is preferred.

Examples of the diamine compound include, but are not limited to, linear aliphatic diamines such as hexamethylenediamine and pentamethylenediamine; and branched-type diamines such as 2-methylpentanediamine and 2-ethylhexamethylenediamine. Aliphatic diamines; aromatic diamines such as p-phenylenediamine and m-phenylenediamine; and alicyclic diamines such as cyclohexanediamine, cyclopentanediamine and cyclooctanediamine.
One of these diamine compounds may be used alone, or two or more thereof may be used in combination.

Examples of the monocarboxylic acid compound include, but are not limited to, acetic acid, propionic acid, butyric acid, valeric acid, caproic acid, caprylic acid, lauric acid, tridecylic acid, myristic acid, palmitic acid, stearic acid, Aliphatic monocarboxylic acids such as pivalic acid and isobutylic acid; alicyclic monocarboxylic acids such as cyclohexanecarboxylic acid; benzoic acid, toluic acid, α-naphthalenecarboxylic acid, β-naphthalenecarboxylic acid, methylnaphthalenecarboxylic acid and phenylacetic acid And other aromatic monocarboxylic acids.
One of these monocarboxylic acid compounds may be used alone, or two or more thereof may be used in combination.

Examples of the dicarboxylic acid compound include, but are not limited to, malonic acid, dimethylmalonic acid, succinic acid, glutaric acid, adipic acid, 2-methyladipic acid, trimethyladipic acid, pimelic acid, 2,2 Aliphatic dicarboxylic acids such as dimethylglutaric acid, 3,3-diethylsuccinic acid, azelaic acid, sebacic acid and suberic acid; alicyclic dicarboxylic acids such as 1,3-cyclopentanedicarboxylic acid and 1,4-cyclohexanedicarboxylic acid Acids: isophthalic acid, 2,6-naphthalenedicarboxylic acid, 2,7-naphthalenedicarboxylic acid, 1,4-naphthalenedicarboxylic acid, 1,4-phenylenedioxydiacetic acid, 1,3-phenylenedioxydiacetic acid, diphen Acid, diphenylmethane-4,4'-dicarboxylic acid, diphenylsulfone-4,4'-dica Units derived from an aromatic dicarboxylic acid such as carbon acid and 4,4'-biphenyl dicarboxylic acid.
One of these dicarboxylic acid compounds may be used alone, or two or more thereof may be used in combination.

  As a method for producing the polyamide resin used in the present invention, for example, adipic acid, a melt polymerization method from a salt of isophthalic acid and hexamethylenediamine, a solid-phase polymerization method, a bulk polymerization method, a solution polymerization method, or a combination thereof Various polycondensations can be used. It can also be obtained from adipic acid chloride, isophthalic acid chloride and hexamethylenediamine by a method such as solution polymerization or interfacial polymerization. Among these, a method based on melt polymerization or a combination of melt polymerization and solid phase polymerization is preferably economically preferable.

  The polyamide resin used in the present invention preferably has a formic acid solution viscosity at 25 ° C. ((5.5 g of polyamide) / (90% formic acid of 50 mL)) of 10 or more and 45 or less, which is measured according to Annex JA of JIS-K6920-2. . It is more preferably from 15 to 35, further preferably from 25 to 35, and still more preferably from 25 to 33. When the formic acid solution has a viscosity of 10 or more, embrittlement of the resin composition can be suppressed, a molded article having practically sufficient mechanical properties can be obtained, and drawing from the nozzle tip of the cylinder during molding is less likely to occur. be able to. When the formic acid solution has a viscosity of 45 or less, the melt viscosity of the resin does not become too high, and the partial rise of the inorganic filler during molding can be suppressed, and the surface gloss can be maintained.

(B) Inorganic filler (B) Inorganic filler (hereinafter sometimes referred to as inorganic filler or component (B)) is not limited to the following, but may be, for example, glass fiber or carbon fiber. , Calcium silicate fiber, potassium titanate fiber, aluminum borate fiber, flake glass, talc, kaolin, mica, hydrotalcite, calcium carbonate, zinc carbonate, zinc oxide, calcium monohydrogen phosphate, wollastonite, silica , Zeolite, alumina, boehmite, aluminum hydroxide, titanium oxide, silicon oxide, magnesium oxide, calcium silicate, sodium aluminosilicate, magnesium silicate, ketjen black, acetylene black, furnace black, carbon nanotube, graphite, brass, copper , Silver, aluminum, d Nickel, iron, calcium fluoride, mica, montmorillonite, swellable fluoromica and apatite.
These may be used alone or in combination of two or more.

  Among the above examples, from the viewpoint of increasing the mechanical strength and rigidity of the polyamide resin composition of the present invention, glass fiber, carbon fiber, flaky glass, talc, kaolin, mica, calcium carbonate, calcium hydrogen phosphate, calcium hydroxide One or more members selected from the group consisting of lastnite, silica, carbon nanotubes, graphite, calcium fluoride, montmorillonite, swellable fluoromica and apatite are preferred. More preferably, it is at least one selected from the group consisting of glass fiber, carbon fiber, wollastonite, talc, mica, kaolin and silicon nitride.

  Among glass fibers and carbon fibers, from the viewpoint of imparting excellent mechanical properties to the polyamide resin composition, the number average fiber diameter is 3 to 30 μm and the weight average fiber length is 100 to 750 μm in the polyamide resin composition. And an aspect ratio (a value obtained by dividing the weight average fiber length by the number average fiber diameter) of the weight average fiber length to the number average fiber diameter of 10 to 100 is more preferable.

  Further, among wollastonite, from the viewpoint that excellent mechanical properties can be imparted to the polyamide resin composition, the number average fiber diameter is 3 to 30 μm and the weight average fiber length is 10 to 10 in the polyamide resin composition. Those having a thickness of 500 μm and an aspect ratio of 3 to 100 are more preferred.

  Further, among talc, mica, kaolin, and silicon nitride, from the viewpoint that excellent mechanical properties can be imparted to the polyamide resin composition, those having a number average particle diameter in the polyamide resin composition of 0.1 to 10 μm. Is more preferred.

Here, the number average fiber diameter, the number average particle diameter, and the weight average fiber length in the inorganic filler are values measured by the following method.
The polyamide resin composition is placed in an electric furnace, the contained organic matter is incinerated, and, for example, 100 or more inorganic fillers are arbitrarily selected from the residue and observed with a SEM (Scanning Electron Microscope, scanning electron microscope). The number average fiber diameter and the number average particle diameter are measured by measuring the fiber diameter and the particle diameter of these inorganic fillers. At the same time, the weight average fiber length is determined by measuring the fiber length using an SEM photograph at a magnification of 1000 times.

The inorganic filler may be subjected to a surface treatment with a silane coupling agent or the like. Examples of the silane coupling agent include, but are not limited to, γ-aminopropyltriethoxysilane, γ-aminopropyltrimethoxysilane, and N-β- (aminoethyl) -γ-aminopropylmethyldimethoxy Aminosilanes such as silane; mercaptosilanes such as γ-mercaptopropyltrimethoxysilane and γ-mercaptopropyltriethoxysilane; epoxy silanes; vinyl silanes.
In particular, one or more selected from the above-listed components is preferable, and aminosilanes are more preferable.

  For glass fibers and carbon fibers, a carboxylic acid anhydride-containing unsaturated vinyl monomer and an unsaturated vinyl monomer other than the carboxylic acid anhydride-containing unsaturated vinyl monomer are further used as a sizing agent. As a copolymer, an epoxy compound, a polycarbodiimide compound, a polyurethane resin, a homopolymer of acrylic acid, a copolymer of acrylic acid and other copolymerizable monomers, and a primary, secondary or tertiary amine thereof. May be included. These may be used alone or in combination of two or more.

The glass fiber and the carbon fiber are obtained by continuously reacting in the known glass fiber and carbon fiber production process. Specifically, using a known method such as a roller type applicator, a glass fiber and a carbon fiber are obtained by drying a fiber strand produced by applying a sizing agent to the glass fiber and the carbon fiber.
The fiber strand may be used as it is as a roving, or may be used as a chopped glass strand after a cutting step. The drying of the strand may be performed after the cutting step, or the cutting step may be performed after the strand is dried.

  From the viewpoint of maintaining the convergence of the glass fiber and the carbon fiber, the amount of the sizing agent added is preferably equivalent to 0.2% by mass or more as a solid content ratio based on 100% by mass of the glass fiber or the carbon fiber. On the other hand, from the viewpoint of improving the thermal stability of the polyamide resin composition of the present invention, the content is preferably 3% by mass or less.

  The ratio of the inorganic filler to 100% by mass of the polyamide resin composition is preferably from 1% by mass to 70% by mass, more preferably from 30% by mass to 70% by mass, and still more preferably from 50% to 60% by mass. % Or less. By setting the content of the inorganic filler to 1% by mass or more based on 100% by mass of the polyamide resin composition, the mechanical strength of the polyamide resin composition of the present invention is improved, and the content is reduced to 70% by mass or less. By doing so, a polyamide resin composition having excellent moldability can be obtained.

(C) Carbon black (C) Carbon black (hereinafter sometimes simply referred to as carbon black or component (C)) is classified into furnace black, channel black, thermal black and the like according to the production method. Are classified into acetylene black, Ketjen black, oil black, gas black, etc., but they can be used in the present invention without any particular limitation.

  The average primary particle size of the carbon black is at least 20 nm, preferably at least 30 nm, more preferably at least 35 nm, even more preferably at least 50 nm, particularly preferably at least 60 nm and at most 100 nm. When the average primary particle size is within this range, the weather resistance can be further improved, which is preferable. The average primary particle diameter was determined by obtaining an image in which carbon black particles were dispersed by the procedure described in the standard of ASTM D3849 (standard test method for carbon black-morphological characterization by electron microscopy). This is a value obtained by measuring the particle size of 2,000 particles and calculating the average of the measured values.

The specific surface area of the carbon black is preferably 100 m ² / g or less, more preferably 85 m ² / g or less, further preferably 70 m ² / g or less, particularly preferably 50 m ² / g or less, and most preferably. 30 m ² / g or less. When the specific surface area is within this range, low warpage, surface appearance and weather gloss retention can be further improved, which is preferable. The specific surface area of carbon black is a value measured from the amount of nitrogen adsorbed according to JIS K6217.

DBP oil absorption of the carbon black (the amount of dibutyl phthalate which carbon black 100g absorbs) is preferably 100cm ³ / 100g or more, and more preferably not more than 100cm ³ / 100g or more 300 cm ³ / 100g, more preferably 100cm ^3/100 g or more 200cm and a ^3/100 g or less, still more preferably not more than 100 cm ^3/100 g or more 150 cm ^3/100 g. When the DBP oil absorption is within this range, the low warpage property, the weather gloss retention and the weather resistance can be further improved. The DBP oil absorption of carbon black is a value measured according to JIS K6221.

  [Specific surface area / DBP oil absorption], which is the ratio between the specific surface area of carbon black and the DBP oil absorption, is 1.0 or less, preferably 0.70 or less, more preferably 0.50 or less, More preferably, it is 0.30 or less, and even more preferably, it is 0.20 or less. When the [specific surface area / DBP oil absorption amount] satisfies this range and the average primary particle diameter of the carbon black is 20 nm or more, the low warpage property, weather resistance, and weather gloss retention can be further improved.

  The content of carbon black with respect to 100% by mass of the polyamide resin composition is preferably 0.02 to 3.0% by mass. It is more preferably 0.02 to 2.0% by mass, further preferably 0.1 to 1.5% by mass, still more preferably 0.3 to 1.3% by mass, and particularly preferably 0.4 to 2.0% by mass. ~ 1.0% by mass. When the content of carbon black is within this range, the weather resistance can be further improved without impairing the appearance of the molded article in the polyamide resin composition.

(D) Copper Compound The polyamide resin composition of the present invention may be described as a copper compound (hereinafter simply referred to as a copper compound or a component (D)) in addition to the components (A) to (C) described above. ) Is selected from copper halide compounds, copper thiocyanate, copper nitrate, copper acetate, naphthenic copper, copper caprate, copper laurate, copper stearate, copper acetylacetone, copper oxide (I) and copper oxide (II) At least one copper compound may be contained.
These may be used alone or in combination of two or more.

  Among the copper compounds listed above, preferably, copper halide compounds (copper fluoride, copper iodide, cuprous bromide, cupric bromide, cuprous chloride, etc.), copper acetate, copper oxide (I ) And copper (II) oxide, more preferably a copper halide compound, even more preferably copper iodide or cuprous bromide. When these are used, a polyamide resin composition having excellent low warpage and weather resistance and capable of effectively suppressing metal corrosion (hereinafter, also simply referred to as metal corrosion) of a screw or a cylinder during extrusion is obtained.

The content of the copper compound with respect to 100% by mass of the polyamide resin composition is preferably 0.001 to 0.2% by mass, more preferably 0.005 to 0.15% by mass, and still more preferably 0.005% by mass. To 0.1 mass%, and still more preferably 0.005 to 0.05 mass%.
When the content of the copper compound in the polyamide resin composition is within the above range, the low warpage property, the weather resistance and the weather glossiness retention rate are further improved, and copper precipitation and metal corrosion can be effectively suppressed. it can.

  Further, from the viewpoint of improving the low warpage property, weather resistance and weather resistance gloss retention of the polyamide resin composition, the content of the copper element with respect to 100% by mass of the polyamide resin composition is preferably 0.001% by mass or more, It is more preferably 0.002% by mass or more, further preferably 0.002 to 0.05% by mass, and still more preferably 0.002 to 0.02% by mass.

(E) Halide of Alkali Metal and / or Alkaline Earth Metal The polyamide resin composition of the present invention provides (E) a halogen of an alkali metal and / or an alkaline earth metal from the viewpoint of improving weather resistance and suppressing metal corrosion. (Hereinafter sometimes simply described as halide or component (E)). (E) Examples of the halide include, but are not limited to, potassium iodide, potassium bromide, sodium iodide, sodium bromide, lithium iodide, lithium bromide, lithium chloride, and calcium iodide. , Calcium bromide, magnesium iodide and magnesium bromide, and mixtures thereof.

  In particular, potassium iodide, potassium bromide, sodium iodide, and sodium bromide are preferable, and potassium iodide or potassium bromide is more preferable, from the viewpoint of improving weather resistance and suppressing metal corrosion.

  The content of the halogen element in the polyamide resin composition is preferably 0.02 with respect to 100% by mass of the polyamide resin composition from the viewpoint of improving the low warpage property, the weather resistance, and the weather glossiness retention of the polyamide resin composition. To 4% by mass, more preferably 0.03 to 1.0% by mass, and still more preferably 0.03 to 0.5% by mass. Here, for example, when the component (D) is a copper halide, the halogen element means the total of the halogen element derived from the copper halide and the halogen element derived from the component (E).

  The total ratio of the (D) copper compound and the (E) halide to 100% by mass of the polyamide resin composition is preferably 0.02 to 5% by mass, more preferably 0.02 to 2% by mass, More preferably, the content is 0.03 to 0.3% by mass. When the total content of the component (D) and the component (E) is within the above range, low warpage, weather resistance and weather gloss retention can be further improved, and copper precipitation and metal corrosion are effectively prevented. Can be suppressed.

The content ratio of the (D) copper compound and the (E) halide is such that the molar ratio of the halogen element to the copper element (halogen element / copper element) is 2/1 to 50/1. Is preferably, more preferably 3/1 to 30/1, and still more preferably 3/1 to 20/1.
Here, for example, when the component (D) is a copper halide, the halogen element means the total of the halogen element derived from the copper halide and the halogen element derived from the component (E).

When the molar ratio between the halogen element and the copper element (halogen element / copper element) is 2/1 or more, the weather resistance can be further improved.
On the other hand, when the molar ratio (halogen element / copper element) is 50/1 or less, corrosion of a screw of a molding machine or the like can be prevented without substantially impairing mechanical properties such as toughness.

(F) Crystallization retarder The polyamide resin composition of the present invention comprises (F) a crystallization retarder (hereinafter simply referred to as a crystallization retarder or (F)) from the viewpoint of further improving the appearance and mechanical strength of a molded article. (Sometimes referred to as a component).
The crystallization retarder is a substance having an effect of lowering the crystallization temperature of the polyamide resin when blended with the polyamide resin. The crystallization temperature can be determined by a differential scanning calorimetry (DSC method) based on JIS K7121.

  Examples of the crystallization retarder include, but are not limited to, azine dyes and phthalocyanine dyes. Nigrosine is preferable as the azine dye, and copper phthalocyanine dye is preferable as the phthalocyanine dye.

  The content of the crystallization retarder based on 100% by mass of the polyamide resin composition is preferably 0.01 to 3.0% by mass. It is more preferably 0.03 to 2.0% by mass, and still more preferably 0.05 to 1.5% by mass. (A) By setting the content of the crystallization retarder to 0.01% by mass or more based on 100% by mass of the polyamide resin, the low warpage property and the appearance of a molded product of the polyamide resin composition of the present invention are improved, and By setting the content to 3.0% by mass or less, a polyamide resin composition having excellent releasability can be obtained.

(G) Lubricant The polyamide resin composition of the present invention further contains (G) a lubricant (hereinafter sometimes simply referred to as a lubricant or a component (G)) from the viewpoint of further improving the appearance of a molded article. Is also good.
Examples of the lubricant include, but are not limited to, higher fatty acids, higher fatty acid esters, higher fatty acid amides, higher fatty acid metal salts, and polyolefin waxes.
One type of lubricant may be used alone, or two or more types may be used in combination.

The higher fatty acid constituting the higher fatty acid compound indicates a higher aliphatic monocarboxylic acid. In particular, fatty acids having 8 or more carbon atoms are preferred. More preferably, it is a fatty acid having 8 to 40 carbon atoms.
Examples of higher fatty acids include, but are not limited to, saturated or unsaturated, linear or branched, aliphatic monocarboxylic acids, and stearic acid, palmitic acid, behenic acid, and erucic acid. Acids, oleic acid, lauric acid, montanic acid and the like.

The higher fatty acid ester is an ester compound of a higher fatty acid and an alcohol.
Examples of the alcohol include, but are not limited to, 1,3-butanediol, trimethylolpropane, stearyl alcohol, behenyl alcohol, lauryl alcohol, and the like.
Examples of the higher fatty acid ester include, but are not limited to, stearyl stearate, behenyl behenate, montanic acid-1,3-butanediol ester, montanic acid-trimethylolpropane ester, and trimethylolpropane trilau. And butyl stearate.

The higher fatty acid amide is an amidated higher fatty acid.
Examples of the higher fatty acid amide include, but are not limited to, stearic amide, oleic amide, erucamide, ethylenebisstearylamide, ethylenebisoleylamide, N-stearylstearylamide, N-stearylerca Amides and the like. Particularly, stearic acid amide, erucic acid amide, ethylene bisstearyl amide, and N-stearyl erucamide are preferred, and ethylene bis stearyl amide and N-stearyl erucamide are more preferred.

The higher fatty acid metal salt is a metal salt of the higher fatty acid described above.
Examples of metal elements that form salts with higher fatty acids include Group 1 elements (alkali metals), Group 2 elements (alkaline earth metals), Group 3 elements, zinc, and aluminum in the periodic table. As the metal element, an alkali metal such as sodium and potassium; an alkaline earth metal such as calcium and magnesium; and aluminum are preferable.

As the higher fatty acid metal salt, a metal salt of montanic acid, a metal salt of behenic acid and a metal salt of stearic acid are preferably used. Calcium, aluminum montanate, zinc montanate, magnesium montanate, sodium behenate, calcium behenate, zinc behenate, calcium laurate, zinc laurate, calcium palmitate, etc .; aluminum stearate, zinc stearate, stearin Magnesium oxide, calcium montanate, zinc montanate, calcium behenate, and zinc behenate are more preferred, and calcium montanate, zinc montanate, and zinc behenate are even more preferred.
These higher fatty acid metal salts may be used alone or in a combination of two or more.

Examples of the polyolefin wax include a polypropylene wax and a polyethylene wax (PE wax).
Polypropylene waxes are generally polypropylenes with wax-like properties, having a correspondingly low molecular weight. The wax used in the present invention has an average molecular weight (mass average) Mw (using GPC (Gel Permeation Chromatography) and standard polystyrene) of 2,000 to 60,000, especially 5,000 to 50,000, especially 10,000 to 45,000. Is preferred.
The softening point of the wax used in the polyamide resin composition of the present invention is calculated according to DIN EN 1427 (ring and ball method), and is preferably at least 140 ° C. or higher, more preferably 150 ° C. or higher.

  Preferred products are Licowax® PP, in particular Licowax PP 230 and Licowax VP PP types (Clariant GmbH) and Ceridust® VP 6071 as well as LC 525 N, LC 502 N of Hana Corporation, Korea. LC 502 NC, LC 503 N, and LC 503 NC types.

  Polyethylene wax is obtained by radical polymerization of a hydrocarbon wax having an average molecular weight range (weight average) of 2000 to 20,000, produced by a high pressure method or by a low pressure method in the presence of a metal organic catalyst. At the same time, low molecular weight products with wax properties can be obtained from high molecular weight polyethylene by pyrolysis.

In general, PE wax is not classified by the manufacturing method, but rather is classified by the density in HDPE (high-density polyethylene) and LDPE (low-density polyethylene). In this case, the high-pressure method reduces the HDPE quality. And the low pressure method results in LDPE quality.
The properties of the pyrolytic PE wax are similar to those of the product obtained by the high pressure method. Also, by changing the implementation of the method, a low density branched type (LDPE) is obtained.
Oxidation with air or oxygen gives a highly polar oxidized PE wax (polyethylene wax oxidation product).

  As starting materials for such oxidation processes, it is possible to use all customary polyolefin waxes, for example those prepared by Ziegler- or Phillips-catalyzed reactions or by high-pressure processes. The base wax can be obtained directly from the polymerization process or obtained by thermal decomposition of a high molecular weight olefin polymer.

  Suitable waxes include, for example, ethylene and / or C3-C10 alk-1-enes, such as propylene, 1-butene, 1-pentene, 1-hexene, 1-heptene, 1-octene, 1-nonene and 1-decene. It is derived from. In particular, ethylene or propylene homopolymers or copolymers, particularly preferably ethylene homopolymers or copolymers, are used as polyolefin waxes.

To prepare the base polyolefin waxes, the monomers are homopolymerized or copolymerized with one another in all proportions. Preferred polyolefins based on oxidized waxes have a density of from 0.89 to 0.98 g / cm ³ , in particular from 0.90 to 0.96 g / cm ³ and from 1000 to 40000 g / mol, in particular from 2000 to 20000 g / mol. Is an ethylene homopolymer having a Mw measured by the GPC method in 1,2,4-trichlorobenzene at 135 ° C. using a polyethylene standard or a polypropylene standard.

  Furthermore, as starting polyolefin, ethylene / polyethylene having a total content of structural units derived from one or more alk-1-enes in the copolymer of from 0.1 to 15 mol%, in particular from 1 to 10 mol%, based on the copolymer / C3-C10 alk-1-ene copolymers are suitable. Preferred ethylene / alk-1-ene copolymers are ethylene / propylene copolymers having a content of structural units derived from propylene in the copolymer of preferably 0.1 to 10 mol%, in particular 1 to 5 mol%, based on the copolymer It is. The copolymer generally has a Mw of 1000 to 40000 g / mol, in particular 2000 to 20000 g / mol, determined by the GPC method as described above.

Other preferred polyolefins, which may be based on oxidized waxes, have a pentadene content (isotactic pentadene) in the range from 90 to 98% as determined by ¹³ C-NMR spectroscopy and from 1000 to 40,000 g / mol, in particular from 2000 to 2000 g / mol. ~ 20000 g / mol isotactic propylene homopolymer with Mw as determined by GPC method as described above.

  Furthermore, copolymers of propylene with ethylene and / or C4 -C10 alk-1-enes are also suitable as base polyolefins. The propylene copolymer usually has a total content of structural units derived from ethylene and / or C4 -C10 alk-1-ene in the copolymer of from 0.1 to 15 mol%, in particular from 1 to 10 mol%, based on the copolymer. Having. Preferred propylene copolymers are propylene / ethylene copolymers having a content of structural units derived from ethylene in the copolymer of 0.1 to 10 mol%, especially 1 to 5 mol%, based on the copolymer. The propylene copolymer generally has a M w of 1000 to 40000 g / mol, in particular 1000 to 20000 g / mol, as determined by the GPC method as described above.

  The acid value of the oxidized wax (according to DIN 53402 or DIN EN D1386) is preferably from 11 to 100 [mg KOH / g], in particular from 12 to 55 [mg KOH / g], in particular from 12 to 30 [mg KOH / g]. g]. The saponification value is preferably from 11 to 100 [mg KOH / g], in particular from 10 to 50 [mg KOH / g], in particular from 20 to 30 [mg KOH / g] (according to DIN EN D-1387).

  The content of the lubricant with respect to 100% by mass of the polyamide resin composition is preferably 0.01 to 10% by mass, more preferably 0.03 to 5% by mass, and is 0.05 to 2% by mass. Is more preferable. By setting the content of the lubricant within the above range, a polyamide resin composition having more excellent appearance, releasability, mechanical strength and plasticity can be obtained.

The polyamide resin composition of the present invention may further contain, if necessary, other components in addition to the components (A) to (G) described above, as long as the effects of the present invention are not impaired.
Other components include, but are not limited to, for example, antioxidants, ultraviolet absorbers, heat stabilizers, light degradation inhibitors, plasticizers, mold release agents, nucleating agents, flame retardants, colorants , A dye or a pigment may be added, or another thermoplastic resin may be mixed.
Here, since the other components have greatly different properties, the preferable content of each component that does not substantially impair the effects of the present invention is various. Then, those skilled in the art can easily set a suitable content for each of the other components described above.

(Production method of polyamide resin composition)
The method for producing the polyamide resin composition of the present invention is not limited to the following. For example, in a state where the component (A) is melted by a single-screw or multi-screw extruder, the components (B) and (C) are melted. Can be used. Above all, using a twin-screw extruder equipped with an upstream supply port and a downstream supply port, the components (A) and (C) are supplied from the upstream supply port and melted, and then the downstream supply port is used. It is preferable to use a method of supplying and melting and kneading the component (B). Also, when using rovings such as glass fiber and carbon fiber, they can be compounded by a known method.

(Molded body)
The molded article of the present invention is obtained by molding the above-described polyamide resin composition of the present invention, and is obtained, for example, by injection molding the polyamide resin composition.

[Application]
The molded article of the present invention is suitably used as various molded articles and parts for, for example, automobiles, machine industry, electric / electronic, housing, industrial materials, industrial materials, and daily / household products. Can be used. In particular, it is suitable for parts for automobiles and dwellings exposed to the outdoors, and can be more suitably used for exterior parts of automobiles.

Hereinafter, the present invention will be described in detail with reference to specific examples and comparative examples, but the present invention is not limited to the following examples.
Hereinafter, evaluation methods performed in Examples and Comparative Examples will be described.

〔Evaluation method〕
<Low warpage>
Using an injection molding machine (PS-40E: manufactured by Nissei Plastics Co., Ltd.), pellets of the polyamide resin compositions obtained in the examples and comparative examples were molded into a 100 × 100 × 2 mm thick (mirror-finished) flat product. Manufactured. At that time, the filling time was set at 1 second, the dwell time was set at 9 seconds, the cooling time was set at 15 seconds, the mold temperature was set at 90 ° C, and the molten resin temperature was set at 290 ° C. After the obtained flat molded product was allowed to stand at 23 ° C. and 50% relative humidity for 24 hours, one of the four corners of the molded product on the surface plate was lifted when one corner was pressed against the surface plate. In contrast, the distance between the lower surface and the surface plate was measured with a caliper with an accuracy of 0.1 mm. Of the raised corners, the one with the largest distance to the platen was taken as a warp. Those with a small warpage value are excellent.

<Molded product appearance>
Pellets of the polyamide resin composition obtained in the examples and comparative examples were manufactured into 80 x 80 x 3 mm-thick mirror-surface flat test pieces using an injection molding machine (PS-40E: manufactured by Nissei Plastic Co., Ltd.). At that time, the filling time was set at 1 second, the dwell time was 9 seconds, the cooling time was 15 seconds, and the molten resin temperature was 290 ° C. The mold temperature was set as follows according to the embodiment. Examples 1 to 9, Comparative Examples 1 to 9: 90 ° C, Examples 10 to 11, Comparative Example 10: 130 ° C. The surface gloss of the obtained flat plate specimen was measured using a gloss meter (VG7000: manufactured by Nippon Denshoku Industries Co., Ltd.) at an incident angle of 60 degrees according to JIS Z8741.

<Weather resistant gloss retention>
Using a xenon arc accelerated weathering tester (Ci4000: manufactured by Atlas Co., Ltd.), the flat plate piece whose surface gloss was measured in accordance with ISO 4894-2, a black panel temperature of 63 ° C., a water spraying time of 18 minutes, and water The accelerated weathering test was performed in a cycle of 102 minutes of the spray stop time. The surface gloss of the flat plate test piece after 1,000 hours of the test time was measured, and the gloss retention was calculated.

<Weather discoloration resistance>
Using an injection molding machine (PS-40E: manufactured by Nissei Plastics Co., Ltd.), the pellets of the polyamide resin composition obtained in the examples and comparative examples were 80 × 80 × 3 mm thick (single-sided grain processing: Yasumi Tanasawa). TH113). At that time, the filling time was set at 1 second, the dwell time was 9 seconds, the cooling time was 15 seconds, and the molten resin temperature was 290 ° C. The mold temperature was set as follows according to the embodiment. Examples 1 to 9 and Comparative Examples 1 to 9: 90 ° C, Examples 10 to 11 and Comparative Example 10: 130 ° C. The textured surface of the obtained flat plate test piece was used as a test surface, and a black panel temperature of 63 ° C. and a water spraying time of 18 minutes were used according to ISO 4894-2 using a xenon arc accelerated weathering tester (Ci4000: manufactured by Atlas). The accelerated weathering test was carried out in a cycle of 102 minutes during which the water spray was stopped. Before the test, after the test time of 1,000 hours and after the test time of 1,500 hours, the color tone was measured using a color difference meter (SE6000: manufactured by Nippon Denshoku Industries Co., Ltd.) in accordance with JIS Z8722. The color change ΔE before and after the test was determined.

<Viscosity of formic acid solution at 25 ° C.>
The measurement was performed according to Appendix JA of JIS-K6920-2. With respect to the polyamide resins used in Examples and Comparative Examples, a polymer solution (proportion of (5.5 g of polyamide) / (50 mL of 90% formic acid)) was prepared using 90% formic acid, and the temperature was 25 ° C. It was measured.

〔raw materials〕
(A) Polyamide resin (PA)
(A-1) Polyamide 66 / 6I, Polyamide of Production Example 1 below Formic acid solution viscosity at 25 ° C .: 27
Structural unit having an aromatic structure in 100% by mass of polyamide resin: 20% by mass
(A-2) Polyamide 6I / 6T, polyamide "Grivory G21" manufactured by EMS Co., Ltd.
Structural unit having an aromatic structure in 100% by mass of polyamide resin: 100% by mass
(A-3) Polyamide MXD6, Polyamide of Production Example 2 below Structural unit having an aromatic structure in 100% by mass of polyamide resin: 48% by mass
(A-4) Polyamide 66, polyamide "1300" manufactured by Asahi Kasei Chemicals Corporation
Structural unit having an aromatic structure in 100% by mass of polyamide resin: 0% by mass
(A-5) Polyamide 6, polyamide "K122" manufactured by DSM Corporation
Structural unit having an aromatic structure in 100% by mass of polyamide resin: 0% by mass

(B) Glass fiber (hereinafter abbreviated as GF) ECS03T-275H manufactured by NEC Corporation

(C) Carbon black (CB)
(C-1) Carbon black having the following characteristics: average primary particle diameter: 85 nm;
Specific surface area / DBP oil absorption: 0.18
Nitrogen adsorption specific surface ^area: 20m 2 / g, DBP oil ^absorption: 110 cm 3/100 g
(C-2) Carbon black having the following characteristics: average primary particle diameter: 55 nm;
Specific surface area / DBP oil absorption: 0.25
Nitrogen adsorption specific surface ^area: 32m 2 / g, DBP oil ^absorption: 130 cm 3/100 g
(C-3) Carbon black having the following characteristics: average primary particle diameter: 29 nm;
Specific surface area / DBP oil absorption: 0.25
Nitrogen adsorption specific surface ^area: 110m 2 / g, DBP oil ^absorption: 440 cm 3/100 g
(C-4) Carbon black having the following characteristics: average primary particle diameter: 30 nm;
Specific surface area / DBP oil absorption: 0.65
Nitrogen adsorption specific surface ^area: 74m 2 / g, DBP oil ^absorption: 113cm 3 / 100g

(C-5) Carbon black having the following characteristics: average primary particle size: 24 nm,
Specific surface area / DBP oil absorption: 1.8
Nitrogen adsorption specific surface ^area: 115m 2 / g, DBP oil ^absorption: 65cm 3 / 100g
(C-6) Carbon black having the following characteristics: average primary particle diameter: 14 nm;
Specific surface area / DBP oil absorption: 0.74
Nitrogen adsorption specific surface ^area: 460m 2 / g, DBP oil ^absorption: 620 cm 3/100 g
(C-7) Carbon black having the following characteristics: average primary particle diameter: 19 nm;
Specific surface area / DBP oil absorption: 1.2
Nitrogen adsorption specific surface ^area: 140m 2 / g, DBP oil ^absorption: 114 cm 3/100 g

(D) Copper iodide (hereinafter abbreviated as CuI) Reagent manufactured by Wako Pure Chemical Industries, Ltd. (E) Potassium iodide (abbreviated as KI) Reagent manufactured by Wako Pure Chemical Industries, Ltd. (F) Crystallization retarder Copper Phthalocyanine dye: C.I. I. Solvent Blue 67
Azine dye: Nigrosine, NUBIAN (registered trademark) BLACK TH-807 manufactured by Orient Chemical Co., Ltd.
(G) Lubricant metal montanate: Recommont NaV101 manufactured by Clariant

[Production Example 1]
Equimolar salts of hexamethylenediamine and adipic acid, and equimolar salts of hexamethylenediamine and isophthalic acid were added at a mass ratio of 80:20, respectively, and pure water was added in the same amount as the charged raw materials, and the inside of the polymerization vessel was added. After sufficient nitrogen replacement, heating was started while stirring. The final temperature reached 270 ° C. while adjusting the pressure in the can to a maximum of 2.0 MPa (G), and the polymer discharged into the water bath was pelletized with a strand cutter. The proportion of the structural unit having an aromatic structure in 100% by mass of the obtained polyamide resin was 20% by mass, and the formic acid solution viscosity at 25 ° C .: 27.

[Production Example 2]
600 g of adipic acid precisely weighed was placed in a 2 L separable flask equipped with a stirrer, a decomposer, a thermometer, a dropping funnel and a nitrogen gas inlet tube, and sufficiently purged with nitrogen. After heating to 190 ° C. and melting uniformly, the mixture was stirred as it was for 20 minutes, and 562 g of meta-xylylenediamine was added dropwise with stirring over 120 minutes. During this time, the reaction temperature was continuously raised to 250 ° C. The condensed water generated by the dropwise addition of the diamine was removed from the system through a condensing device and a total condensing device. After the end of the diamine addition, the reaction was continued at an internal temperature of 258 ° C. for 60 minutes. The proportion of the structural unit having an aromatic structure in 100% by mass of the obtained polyamide resin was 48% by mass.

[Examples 1 to 11], [Comparative Examples 1 to 10]
L / D (extruder cylinder length / extruder cylinder diameter) having an upstream supply port in the first barrel from the upstream side of the extruder and a downstream supply port in the ninth barrel = 48 (barrel number: 12) twin-screw extruder [ZSK-26MC: manufactured by Coperion (Germany)] was used. In the twin-screw extruder, the temperature from the upstream supply port to the die was set to 300 ° C., the screw rotation speed was set to 250 rpm, and the discharge rate was set to 25 kg / hour.

  Under such conditions, (A) PA, (C) CB, (D) CuI, (E) KI, (F) crystal And (G) a lubricant, and (B) GF was supplied from a downstream supply port. These were melt-kneaded to produce polyamide resin composition pellets. The obtained polyamide resin composition was molded at the above-described molten resin temperature and mold temperature, and the appearance of the molded article, weather gloss retention, weather discoloration resistance, and tensile strength were evaluated.

  The evaluation (counting) results and the like are shown in Tables 1, 2, and 3 below. In Tables 1, 2 and 3, the lower the warpage property, the smaller the numerical value. The larger the value of the appearance (surface gloss) of the molded product, the better the appearance of the molded product. The larger the numerical value of the weather resistance gloss retention and the smaller the color tone change ΔE, the better the weather resistance.

  As shown in Table 1, (A) Examples in which the polyamide resin contains an aromatic polyamide, (C) the specific surface area of carbon black / DBP oil absorption is 1.0 or less, and the average primary particle diameter is 20 nm or more. In Nos. 1 to 4, a polyamide resin composition having low warpage, good appearance of a molded product, and excellent weather gloss retention and weather resistance was obtained. On the other hand, even if (A) the polyamide resin contains an aromatic polyamide, (C) the specific surface area of carbon black / DBP oil absorption exceeds 1.0, or (C) the average primary particle diameter of carbon black Comparative Examples 1 to 3 having a particle diameter of less than 20 nm were inferior to the Examples in low warpage, appearance, weather gloss retention, and weather resistance. Further, as in Comparative Examples 4 to 6, when the aromatic resin was not contained in the polyamide resin (A), the low warpage property, the appearance, the weather resistance and gloss retention and the weather resistance were inferior to those of the examples. Furthermore, when the aromatic polyamide is not contained in the polyamide resin (A), the specific surface area / DBP oil absorption which shows excellent low warpage, appearance, weather gloss retention and weather resistance in Example 1 is 1 Even when carbon black (C) having an average primary particle diameter of 20 nm or more was used, the low warpage property, appearance, weather gloss retention, and weather resistance were inferior as shown in Comparative Example 4.

  Further, as shown in Table 2, (A) the polyamide resin contains an aromatic polyamide, (C) the carbon black has a specific surface area / DBP oil absorption of 1.0 or less, and an average primary particle diameter of 20 nm or more. Examples 5 to 8 were excellent in low warpage, appearance, weather gloss retention and weather resistance, regardless of whether (D) copper compound, (E) halide, or (F) crystallization retarder was contained. showed that. On the other hand, when (D) a copper compound and (E) a halide were not contained and (C) specific surface area of carbon black / DBP oil absorption exceeded 1.0, (A) as in Comparative Example 7 ) Even if the polyamide resin contained an aromatic polyamide, the low warpage property, the appearance, the retention of weather gloss and the weather resistance were poor. When (D) a copper compound, (E) a halide is not contained, and (A) a polyamide resin does not contain an aromatic polyamide, (C) specific surface area of carbon black / DBP oil absorption is 1.0 or less, and Even when the average primary particle size was 20 nm or more, low warpage, appearance, weather gloss retention, and weather resistance were poor as in Comparative Example 8. In Example 7, since the content of GF was higher than that of the other Examples, Example 8 did not contain (F) a crystallization retarder, so that the appearance of the molded article was slightly lowered. The properties were comparable to those of the other examples.

  Examples 9 to 11 shown in Table 3 are cases in which (A) the polyamide resin is changed. When (A) the polyamide resin contains an aromatic polyamide, (C) carbon black as in Example 10 If the specific surface area / DBP oil absorption of the sample was 1.0 or less and the average primary particle diameter was 20 nm or more, it was excellent in low warpage, appearance, weather gloss retention, and weather resistance. Further, as in Examples 9 and 11, if (C) carbon black specific surface area / DBP oil absorption is 1.0 or less and average primary particle diameter is 20 nm or more, it is a blend with aliphatic amide. It was also found that they also had excellent low warpage properties, appearance, weather resistance gloss retention and weather resistance. Conversely, even when the polyamide resin (A) contains an aromatic polyamide as in Comparative Examples 9 and 10, (C) the carbon black has a specific surface area / DBP oil absorption of more than 1.0 and an average primary particle diameter of more than 1.0. When it is less than 20 nm, it was found that the low warpage property, the appearance, the weather resistance gloss retention and the weather resistance were inferior.

  From the above, it was found that the polyamide resin composition of the present invention can provide a molded article having excellent low warpage and weather resistance, and further having a good appearance.

  INDUSTRIAL APPLICABILITY The polyamide resin composition of the present invention has industrial applicability as a material for molded articles requiring high levels of low warpage, weather resistance and appearance, such as automotive exterior parts and housing-related parts.

Claims (16)

(A) a polyamide resin;
(B) an inorganic filler;
(C) carbon black,
A polyamide resin composition containing
At least a part of the (A) polyamide resin is (a1) an aromatic polyamide,
(C) The polyamide resin composition, wherein the carbon black has an average primary particle diameter of 20 nm or more and a specific surface area / DBP oil absorption of 1.0 or less, which is a ratio of the specific surface area to the DBP oil absorption.   The polyamide resin composition according to claim 1, wherein the proportion of the structural unit having an aromatic structure is 5 to 100% by mass relative to 100% by mass of all the constituent units constituting the polyamide resin (A).   (A) the polyamide resin contains (a2) an aliphatic polyamide as an optional component, and a ratio of the (a1) aromatic polyamide to 100% by mass of the (A) polyamide resin is 10% by mass or more and 100% by mass or less; The polyamide resin composition according to claim 1, wherein the proportion of the (a2) aliphatic polyamide is 0% by mass or more and 90% by mass or less.   (A1) The aromatic polyamide contains at least one selected from the group consisting of polyamide 4T, polyamide 4I, polyamide 6T, polyamide 6I, polyamide MXD6, polyamide MXD10, polyamide MXD12, polyamide PXD6, polyamide PXD10, and polyamide PXD12. Item 6. The polyamide resin composition according to Item 1, 2 or 3.   The (a2) aliphatic polyamide comprises polyamide 6, polyamide 11, polyamide 12, polyamide 46, polyamide 410, polyamide 412, polyamide 66, polyamide 610, polyamide 612, polyamide 1010, polyamide 1012, and at least one of these. The polyamide resin composition according to any one of claims 1 to 4, wherein the polyamide resin composition is at least one selected from copolymerized polyamides contained as a component.   The polyamide resin composition according to any one of claims 1 to 5, wherein the (C) carbon black has an average primary particle diameter of 35 nm or more. Wherein (C) the polyamide resin composition as claimed in any one claims 1-6 specific surface area of the carbon black is not more than 100 m 2 / ^g. Wherein (C) the polyamide resin composition as claimed in any one claims 1 to 7 DBP oil absorption of the carbon black is 100 cm ^3/100 g or more.   The composition further contains (D) a copper compound, wherein the (D) copper compound is a copper halide compound, copper thiocyanate, copper nitrate, copper acetate, naphthene copper, copper caprate, copper laurate, copper stearate, copper acetylacetone. The polyamide resin composition according to any one of claims 1 to 8, wherein the polyamide resin composition is at least one selected from a group consisting of copper (I) oxide and copper (II) oxide.   The polyamide resin composition according to any one of claims 1 to 9, further comprising (E) a halide of an alkali metal and / or an alkaline earth metal.   The polyamide resin composition according to any one of claims 1 to 10, further comprising (F) a crystallization retarder.   The polyamide resin composition according to claim 11, wherein the (F) crystallization retarder is an azine-based dye or a phthalocyanine-based dye.   13. The composition according to claim 1, further comprising (G) a lubricant, wherein the (G) lubricant is at least one selected from higher fatty acids, higher fatty acid esters, higher fatty acid amides, higher fatty acid metal salts, and polyolefin waxes. The polyamide resin composition according to the above.   The polyamide resin composition according to any one of claims 1 to 13, wherein a ratio of the (B) inorganic filler to 100% by mass of the polyamide resin composition is 30% by mass or more and 70% by mass or less.   A molded article obtained by molding the polyamide resin composition according to any one of claims 1 to 14.   The molded article according to claim 15, which is an automobile exterior part.