Polyamide resin composition pellets, method for producing the same, and molded article

Abstract

To provide a pellet that can produce a molding having excellent appearance, mechanical strength, and elongation properties, a method for producing the same, and a molding obtained from the pellet.SOLUTION: A polyamide resin composition pellet is formed from a polyamide resin composition comprising a polyamide (A), copper compound powder (B), and metal halide solution (C), the pellet comprising aggregates, the aggregates having an average particle size of 7 μm or less. In the pellet, the ratio of the metal halide (c1) relative to the copper compound (b1), (c1) / (b1), is 4 or more in mass.SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to polyamide resin composition pellets, a method for producing the same, and a molded article obtained from the polyamide resin composition pellets. More specifically, the present invention relates to pellets capable of producing a molded article excellent in appearance, mechanical strength, and elongation characteristics, a method for producing the same, and a molded article.

Background Art

[0002] Polyamide resins are excellent in mechanical strength, toughness (elongation characteristics), heat resistance, chemical resistance, etc., and have been conventionally used for various parts such as mechanical parts of automobiles. In recent years, with the increase in the environmental temperature in the engine room, higher long-term heat resistance than ever has been required.

[0003] It is already known that copper compounds such as copper halides and halides of alkali metals or alkaline earth metals are effective as heat-resistant agents for satisfying long-term heat resistance. However, these heat-resistant agents, particularly potassium halide, have deliquescence and become lumpy when stored in the atmosphere. Therefore, it is very difficult to uniformly disperse them in polyamide, and the heat-resistant agent remaining in lumps without being uniformly dispersed causes deterioration of the physical properties of the polyamide resin composition. In addition, it appears as spots on the surface of the product after injection molding, deteriorating the appearance and significantly reducing the value of the product.

[0004] To solve these problems, various techniques have been proposed as techniques for blending a heat-resistant agent into a polyamide resin. For example, Patent Document 1 describes a technique in which fine powder of a halide of an alkali metal or an alkaline earth metal and a lubricant are previously mixed and blended into a polyamide resin. Patent Document 2 describes a technique in which an aqueous solution of a copper compound and an aqueous solution of an inorganic halide are added to polyamide pellets, mixed, and dried. Patent Document 3 describes a technique in which an aqueous solution containing potassium halide and copper halide is added to an extruder with a vent and blended into a polyamide resin composition. Patent Document 4 describes a technique of blending a polyamide resin containing a certain amount of moisture with a polyamide masterbatch obtained by mixing a finely pulverized halogen compound, a copper compound, and an organic compound having at least one amide group, followed by melt-kneading, into the polyamide resin.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Patent Document 2

Patent Document 3

Patent Document 4

Summary of the Invention

Problems to be Solved by the Invention

[0006] In the polyamide resin composition of Patent Document 1, since a halide of an alkali metal or an alkaline earth metal is mixed as fine powder instead of as a solution, the dispersibility of the fine powder in the molded body obtained from the composition is poor, resulting in a problem of inferior appearance. Further, since a lubricant that is not originally required as a heat-resistant agent is added, there is a problem of causing a decrease in the physical properties and an increase in the cost of the polyamide resin composition having heat resistance.

[0007] The technique of Patent Document 2 involves impregnating pellets with an aqueous solution and then drying them, which is time-consuming. As a result, each compound is unevenly distributed on the pellet surface, leading to inferior appearance. Additionally, there is a problem that pellets containing a sufficient amount of a copper compound and / or an inorganic halide cannot be obtained. Further, in the technique of Patent Document 2, when the concentration of the copper compound in the aqueous solution of the copper compound is increased, it becomes a suspension state, and there is a problem that the particle size of the copper compound in the obtained pellets becomes large, resulting in even more inferior appearance.

[0008] The technique of Patent Document 3 has a problem that since the solubility of copper halide in water is low, the addition amount of copper halide and / or potassium halide is reduced, and as a result, the heat aging resistance of the obtained pellets is lowered. Further, the technique of Patent Document 3 has a problem that since it is necessary to use hot water, a special device is required.

[0009] The technique of Patent Document 4 has a problem that an organic compound that is not originally required as a heat-resistant agent is added, which causes a decrease in the physical properties and an increase in the cost of the polyamide resin composition having heat resistance. Further, the technique of Patent Document 4 has a problem that it takes a lot of man-hours to pulverize the heat-resistant agent to obtain fine powder, and the fine powder flies up, resulting in poor workability. Additionally, the technique of Patent Document 4 has a problem that the finely pulverized halogen compound and copper compound may re-aggregate, resulting in poor appearance and insufficient strength of the obtained pellets.

[0010] An object of the present invention is to provide polyamide resin composition pellets capable of manufacturing a molded body excellent in appearance, mechanical strength, and elongation characteristics, a method for manufacturing the same, and a molded body obtained from the pellets.

Means for Solving the Problems

[0011] As a result of intensive studies to solve the above problems, the inventors of the present invention have found that a pellet formed from a polyamide resin composition containing a polyamide, a copper compound powder, and a metal halide solution, which contains aggregates having a specific particle size and in which the copper compound and the metal halide are in a specific ratio, has excellent appearance, mechanical strength, and elongation characteristics. Based on this finding, further studies were conducted to complete the present invention.

[0012] That is, the present invention provides the following [1] to

[13] . [1] A pellet formed from a polyamide resin composition containing a polyamide (A), a copper compound powder (B), and a metal halide solution (C), wherein the pellet contains aggregates, the average particle size of the aggregates is 7 μm or less, and the ratio (c1) / (b1) of the metal halide (c1) to the copper compound (b1) in the pellet is 4 times or more on a mass basis. A polyamide resin composition pellet.

[0013] [2] The polyamide resin composition pellet according to [1] above, wherein the color tone of the polyamide resin composition pellet satisfies the following formula (1). L * ≧74.0 ··· (1) [In formula (1), L * is the L defined by the CIE1976 (L * a * b * ) color system of the polyamide resin composition pellet. * . [3] The polyamide resin composition pellet according to [1] or [2] above, wherein the copper compound (b1) is copper iodide or copper bromide. [4] The polyamide resin composition pellet according to any one of [1] to [3] above, wherein the aggregate is composed of at least one of the copper compound (b1) and the metal halide (c1).

[0014] [5] A method for producing polyamide resin composition pellets, which comprises feeding polyamide (A), copper compound powder (B), and metal halide solution (C) into a melt extruder to obtain polyamide resin composition pellets, wherein the pellets contain aggregates, the metal halide solution (C) contains a metal halide (c1) and a solvent for dissolving the metal halide (c1), the ratio (c1) / (B) of the metal halide (c1) to the copper compound powder (B) is 4 times or more on a mass basis, and after feeding the polyamide (A) and the metal halide solution (C) into the melt extruder, the copper compound powder (B) is fed into the melt extruder. [6] The method for producing polyamide resin composition pellets according to the above [5], wherein the average particle diameter of the aggregates is 7 μm or less.

[0015] [7] After feeding the polyamide (A) into the melt extruder, the metal halide solution (C) is fed into the melt extruder, and after feeding the metal halide solution (C) into the melt extruder, the copper compound powder (B) is fed into the melt extruder. The method for producing polyamide resin composition pellets according to the above [5] or [6]. [8] The method for producing polyamide resin composition pellets according to any one of the above [5] to [7], wherein the metal halide solution (C) is at least one solution (C1) selected from the group consisting of halogen compounds of alkali metals and halogen compounds of alkaline earth metals. [9] The method for producing polyamide resin composition pellets according to any one of the above [5] to [8], wherein the metal halide solution (C) is an aqueous metal halide solution.

[10] The method for producing polyamide resin composition pellets according to any one of the above [5] to [9], wherein the metal halide solution (C) is an aqueous solution of potassium iodide or an aqueous solution of potassium bromide.

[11] The method for producing polyamide resin composition pellets according to any one of the above [5] to

[10] , wherein the melt extruder is provided with two or more sample inlets.

[12] A molded article obtained from the polyamide resin composition pellets according to any one of [1] to [4] above.

[13] A molded article obtained from the polyamide resin composition pellets produced by the method for producing polyamide resin composition pellets according to any one of [5] to

[11] above. [Advantages of the Invention]

[0016] According to the present invention, it is possible to provide polyamide resin composition pellets capable of producing a molded article excellent in appearance, mechanical strength, and elongation characteristics, a method for producing the same, and a molded article obtained from the pellets. [Embodiments for Carrying Out the Invention]

[0017] [Polyamide Resin Composition Pellets] The polyamide resin composition pellets of the present invention are pellets formed from a polyamide resin composition containing a polyamide (A), a copper compound powder (B), and a metal halide solution (C), wherein the pellets contain aggregates, the average particle diameter of the aggregates is 7 μm or less, and the ratio (c1) / (b1) of the metal halide (c1) to the copper compound (b1) in the pellets is 4 times or more on a mass basis.

[0018] According to the present invention, the reason for being able to produce a molded article excellent in appearance, mechanical strength, and elongation characteristics is unclear, but it is presumed as follows. According to the present invention, by using a solution as the metal halide, the metal halide is evenly dispersed in the pellets. As a result, the contact frequency between the metal halide and the copper compound also dispersed in the pellets increases. Therefore, even when the copper compound changes from monovalent copper to divalent copper due to the thermal aging prevention reaction, the divalent copper is returned to monovalent copper by the metal halide in contact with the divalent copper. Therefore, it is considered that the molded article obtained by using the pellets is prevented from being colored and has excellent appearance. Further, according to the present invention, by using a solution as the metal halide, the amount of heat applied to the resin due to the evaporation of the solvent used is reduced, thereby suppressing thermal deterioration. As a result, the brightness of the obtained pellets is increased. Thereby, when coloring the pellets to obtain a molded article of a desired color, it becomes easier to color the target color, and a molded article having excellent appearance can be obtained. Also, according to the present invention, since a powder is used as the copper compound, a larger amount of the copper compound can be contained in the pellets as compared with the case of using a solution as the copper compound. Thereby, a molded article using the pellets has excellent heat resistance.

[0019] Also, according to the present invention, since the average particle diameter of the aggregates present in the pellets is 7 μm or less, coloring is prevented, and a decrease in strength due to coarse aggregated particles is also prevented. Thereby, a molded article obtained using the pellets is excellent in appearance, mechanical strength, and elongation characteristics. Also, according to the present invention, since the average particle diameter of the aggregates present in the pellets is 7 μm or less, the metal halide and the copper compound are homogeneously dispersed in the pellets without excessive aggregation. Therefore, the contact frequency between the metal halide and the copper compound increases. Therefore, even when the copper compound changes from monovalent copper to divalent copper by a heat aging prevention reaction, the divalent copper is returned to monovalent copper by the metal halide in contact with the divalent copper. Therefore, it is considered that a molded article obtained using the pellets is prevented from coloring and has excellent appearance. Also, according to the present invention, since the ratio (c1) / (b1) of the metal halide (c1) to the copper compound (b1) in the pellets is 4 times or more on a mass basis, the possibility of the copper compound contacting the metal halide increases. As a result, the brightness of the pellets increases. Thereby, it becomes easier to color the target color when coloring the pellets, and a molded article having excellent appearance can be manufactured.

[0020] <Polyamide (A)> The polyamide (A) used in the present invention is not particularly limited, but a polyamide having 6 to 13 carbon atoms per amide group in the repeating unit of the polyamide is preferred. When the number of carbon atoms per amide group in the repeating unit of the polyamide is within the above range, the mechanical properties of the molded article are improved and the water absorption is low. From these viewpoints, the number of carbon atoms per amide group in the repeating unit is preferably 7 to 13, more preferably 8 to 13. The "number of carbon atoms per amide group" is the average value of the total number of carbon atoms (including the carbon atoms of the amide group) contained in each repeating unit per amide group.

[0021] The polyamide (A) used in the present invention can be produced, for example, using aminocarboxylic acid, lactam, diamine, dicarboxylic acid, etc. as main raw materials. Examples of the raw materials include aminocarboxylic acids such as 6-aminocaproic acid, 11-aminoundecanoic acid, 12-aminododecanoic acid, and para-aminomethylbenzoic acid; lactams such as ε-caprolactam and ω-laurolactam; aliphatic diamines such as 1,4-tetramethylenediamine, 1,5-pentamethylenediamine, 1,6-hexamethylenediamine, 2-methylpentamethylenediamine, 2,2,4-trimethyl-1,6-hexamethylenediamine, 2,4,4-trimethyl-1,6-hexamethylenediamine, 1,7-heptamethylenediamine, 1,8-octamethylenediamine, 1,9-nonamethylenediamine (1,9-nonanediamine), 2-methyl-1,8-octamethylenediamine, 2-ethyl-1,7-heptanediamine, 1,10-decamethylenediamine, 1,11-undecamethylenediamine, 1,12-dodecamethylenediamine, 1,13-tridecamethylenediamine, and 5-methylnonamethylenediamine; alicyclic diamines such as 1,3-bis(aminomethyl)cyclohexane, 1,4-bis(aminomethyl)cyclohexane, 1-amino-3-aminomethyl-3,5,5-trimethylcyclohexane, bis(4-aminocyclohexyl)methane, bis(3-methyl-4-aminocyclohexyl)methane, 2,2-bis(4-aminocyclohexyl)propane, bis(aminopropyl)piperazine, and aminoethylpiperazine; aromatic diamines such as metaxylylenediamine and paraxylylenediamine; aliphatic dicarboxylic acids such as oxalic acid, malonic acid, dimethylmalonic acid, succinic acid, glutaric acid, adipic acid, 2-methyladipic acid, pimelic acid, 2,2-dimethylglutaric acid, suberic acid, 2,2-diethylsuccinic acid, azelaic acid, sebacic acid, dodecanedioic acid, and dimer acid; and alicyclic dicarboxylic acids such as 1,3-cyclohexanedicarboxylic acid and 1,4-cyclohexanedicarboxylic acid;Examples of aromatic dicarboxylic acids include terephthalic acid, isophthalic acid, phthalic acid, 1,4-naphthalenedicarboxylic acid, 2,6-naphthalenedicarboxylic acid, 2,7-naphthalenedicarboxylic acid, 1,4-phenylenedioxydiacetic acid, 1,3-phenylenedioxydiacetic acid, diphenic acid, 4,4'-oxydibenzoic acid, diphenylmethane-4,4'-dicarboxylic acid, diphenylsulfone-4,4'-dicarboxylic acid, 4,4'-biphenyldicarboxylic acid, and the like.; In the present invention, one of the homopolymers or copolymers derived from these raw materials may be used alone, or two or more thereof may be used in combination.

[0022] Specific examples of the polyamide (A) include polycaproamide (nylon 6), polyhexamethylene adipamide (nylon 66), polytetramethylene adipamide (nylon 46), polytetramethylene sebacamide (nylon 410), polypentamethylene adipamide (nylon 56), polypentamethylene sebacamide (nylon 510), polyhexamethylene sebacamide (nylon 610), polyhexamethylene dodecamide (nylon 612), polydecamethylene adipamide (nylon 106), polydecamethylene sebacamide (nylon 1010), polydecamethylene dodecamide (nylon 1012), polyundecanamide (nylon 11), polydodecanamide (nylon 12), polycaproamide / polyhexamethylene adipamide copolymer (nylon 6 / 66), polytetramethylene terephthalamide (nylon 4T), polyhexamethylene terephthalamide (nylon 6T), polytetramethylene terephthalamide / polyhexamethylene terephthalamide copolymer (nylon 6T / 4T), polyhexamethylene adipamide / polyhexamethylene terephthalamide / polytetramethylene terephthalamide / polytetramethylene adipamide copolymer (nylon 66 / 6T / 4T / 46), polyhexamethylene terephthalamide / polycaproamide copolymer (nylon 6T / 6), polyhexamethylene terephthalamide / polyundecanamide copolymer (nylon 6T / 11), polyhexamethylene terephthalamide / polydodecanamide copolymer (nylon 6T / 12), polyhexamethylene adipamide / polyhexamethylene terephthalamide copolymer (nylon 66 / 6T), polyhexamethylene adipamide / polyhexamethylene isophthalamide copolymer (nylon 66 / 6I), polyhexamethylene adipamide / polyhexamethylene isophthalamide / polycaproamide copolymer (nylon 66 / 6I / 6), polyhexamethylene adipamide / polyhexamethylene terephthalamide / polyhexamethylene isophthalamide copolymer (nylon 66 / 6T / 6I), polyhexamethylene terephthalamide / polyhexamethylene isophthalamide copolymer (nylon 6T / 6I),Polyhexamethylene terephthalamide / poly(2-methylpentamethylene) terephthalamide copolymer (nylon 6T / M5T), polynonamethylene terephthalamide (nylon 9T), poly(2-methyloctamethylene) terephthalamide (nylon M8T), polynonamethylene terephthalamide / poly(2-methyloctamethylene) terephthalamide copolymer (nylon 9T / M8T), polydecamethylene terephthalamide (nylon 10T), polyundecamethylene terephthalamide (nylon 11T), polydodecamethylene terephthalamide (nylon 12T), polypentamethylene terephthalamide / polydecamethylene terephthalamide copolymer (nylon 5T / 10T), polydecamethylene terephthalamide / polyhexamethylene dodecanamide copolymer (nylon 10T / 612), polydecamethylene terephthalamide / polyhexamethylene terephthalamide copolymer (nylon 10T / 6T), polydecamethylene terephthalamide / polyhexamethylene adipamide copolymer (nylon 10T / 66), polyhexamethylene adipamide / polyhexamethylene terephthalamide / polydecamethylene terephthalamide / polydecamethylene methylene adipamide copolymer (nylon 66 / 6T / 10T / 106), polydecamethylene terephthalamide / polyundecanamide copolymer (nylon 10T / 11), polynonamethylene naphthalenedicarboxamide (nylon 9N), polynonamethylene naphthalenedicarboxamide / poly(2-methyloctamethylene) naphthalenedicarboxamide copolymer (nylon 9N / M8N), polyhexamethylene cyclohexanedicarboxamide (nylon 6C), polyhexamethylene cyclohexanedicarboxamide / poly(2-methylpentamethylene) cyclohexanedicarboxamide copolymer (nylon 6C / M5C), polynonamethylene cyclohexanedicarboxamide (nylon 9C), poly(2-methyloctamethylene) cyclohexanedicarboxamide (nylon M8C), polynonamethylene cyclohexanedicarboxamide / poly(2-methyloctamethylene) cyclohexanedicarboxamide copolymer (nylon 9C / M8C) and mixtures or copolymers thereof, etc. can be mentioned.

[0023] Among these, from the viewpoint of improving the heat resistance, high-temperature rigidity, and chemical resistance of the molded article, polynonamethylene terephthalamide (nylon 9T), polynonamethylene terephthalamide / poly(2-methyloctamethylene) terephthalamide copolymer (nylon 9T / M8T), polydecamethylene terephthalamide (nylon 10T), polytetramethylene adipamide (nylon 46), polynonamethylene naphthalenedicarboxamide (nylon 9N), polynonamethylene naphthalenedicarboxamide / poly(2-methyloctamethylene) naphthalenedicarboxamide copolymer (nylon 9N / M8N), polynonamethylene cyclohexanedicarboxamide (nylon 9C), poly(2-methyloctamethylene) cyclohexanedicarboxamide (nylon M8C), polynonamethylene cyclohexanedicarboxamide / poly(2-methyloctamethylene) cyclohexanedicarboxamide copolymer (nylon 9C / M8C) are preferred, and polynonamethylene terephthalamide (nylon 9T), polynonamethylene terephthalamide / poly(2-methyloctamethylene) terephthalamide copolymer (nylon 9T / M8T), polynonamethylene naphthalenedicarboxamide / poly(2-methyloctamethylene) naphthalenedicarboxamide copolymer (nylon 9N / M8N) are more preferred.

[0024] The polyamide (A) used in the present invention is preferably a semi-aromatic polyamide containing an aromatic ring in the repeating unit from the viewpoint of improving the heat resistance and high-temperature rigidity of the molded article. Among them, a semi-aromatic polyamide made from an aliphatic diamine and an aromatic dicarboxylic acid as raw materials is more preferred.

[0025] As the aliphatic diamine constituting the semi-aromatic polyamide, an aliphatic diamine having 4 to 18 carbon atoms is preferred from the viewpoint of improving the heat resistance and the like of the molded article. Also, if the number of carbon atoms is within this range, the melting point will be lowered to some extent, so the processing temperature when making pellets can also be lowered. Therefore, the appearance of the pellets is also improved. In addition, as the aliphatic diamine constituting the semi-aromatic polyamide, an aliphatic diamine having 4 to 18 carbon atoms and another aliphatic diamine may be used in combination. In that case, the content of the aliphatic diamine having 4 to 18 carbon atoms in the total amount of the aliphatic diamine is preferably 50 to 100 mol%, more preferably 60 to 100 mol%, still more preferably 75 to 100 mol%, and particularly preferably 90 to 100 mol%.

[0026] As the aliphatic diamine having 4 to 18 carbon atoms, it is preferable to use at least one of 1,9-nonanediamine and 2-methyl-1,8-octanediamine, and more preferably to use both in combination. When 1,9-nonanediamine and 2-methyl-1,8-octanediamine are used in combination, the molar ratio of 1,9-nonanediamine:2-methyl-1,8-octanediamine is preferably 99:1 to 1:99, more preferably 95:5 to 50:50, and still more preferably 90:10 to 75:25. When the molar ratio of 1,9-nonanediamine and 2-methyl-1,8-octanediamine is within the above range, the heat resistance, high-temperature rigidity, dimensional stability, and moldability of the molded body are improved.

[0027] As the aromatic dicarboxylic acid constituting the semi-aromatic polyamide, terephthalic acid and naphthalenedicarboxylic acid are preferable, and terephthalic acid is more preferable. The total content of terephthalic acid and naphthalenedicarboxylic acid in the total amount of the aromatic dicarboxylic acid constituting the semi-aromatic polyamide is preferably 50 to 100 mol%, more preferably 60 to 100 mol%, still more preferably 75 to 100 mol%, and even more preferably 90 to 100 mol%. When the total content of terephthalic acid and naphthalenedicarboxylic acid in the total amount of the aromatic dicarboxylic acid is within the above range, the heat resistance of the molded body is improved.

[0028] In addition, the content of the aliphatic diamine having 4 to 18 carbon atoms in the total amount of the monomers constituting the semi-aromatic polyamide is preferably 30 to 55 mol%, more preferably 40 to 55 mol%, the content of the aromatic dicarboxylic acid is preferably 30 to 55 mol%, and more preferably 40 to 55 mol%.

[0029] It is preferable that at least a part of the terminal of the polyamide (A) is blocked by a terminal blocking agent. When the terminal is blocked, the melt moldability and the like of the resulting thermoplastic resin composition become more excellent.

[0030] As the terminal blocking agent for blocking the terminal of the polyamide (A), a monofunctional compound having reactivity with the amino group or carboxyl group at the polyamide terminal can be used. From the viewpoints of reactivity, stability of the blocked terminal, etc., monocarboxylic acid or monoamine is preferable, and monocarboxylic acid is more preferable from the viewpoint of ease of handling, etc. In addition, acid anhydrides, monoisocyanates, monoacid halides, monoesters, and monoalcohols can also be used.

[0031] Examples of the monocarboxylic acid used as the terminal blocking agent include aliphatic monocarboxylic acids such as acetic acid, propionic acid, butyric acid, valeric acid, caproic acid, caprylic acid, lauric acid, tridecanoic acid, myristic acid, palmitic acid, stearic acid, pivalic acid, and isobutyric acid; alicyclic monocarboxylic acids such as cyclohexanecarboxylic acid; and aromatic monocarboxylic acids such as benzoic acid, toluic acid, α-naphthalenecarboxylic acid, β-naphthalenecarboxylic acid, methylnaphthalenecarboxylic acid, and phenylacetic acid. These may be used alone or in combination of two or more. Among these, from the viewpoints of reactivity, stability of the blocked terminal, and production cost, etc., acetic acid, propionic acid, butyric acid, valeric acid, caproic acid, caprylic acid, lauric acid, tridecanoic acid, myristic acid, palmitic acid, stearic acid, and benzoic acid are preferable.

[0032] Examples of the monoamine used as the terminal stopper include aliphatic monoamines such as methylamine, ethylamine, propylamine, butylamine, hexylamine, octylamine, decylamine, stearylamine, dimethylamine, diethylamine, dipropylamine, and dibutylamine; alicyclic monoamines such as cyclohexylamine and dicyclohexylamine; aromatic monoamines such as aniline, toluidine, diphenylamine, and naphthylamine. These may be used alone or in combination of two or more. Among these, butylamine, hexylamine, octylamine, decylamine, stearylamine, cyclohexylamine, and aniline are preferred from the viewpoints of reactivity, boiling point, stability of the sealed end, and production cost.

[0033] The polyamide (A) used in the present invention can be produced by a known method. For example, methods such as a melt polymerization method, a solid-phase polymerization method, and a melt extrusion polymerization method using aminocarboxylic acid, lactam, dicarboxylic acid, diamine, etc. as raw materials can be mentioned. As a method for producing the polyamide (A), for example, first, a dicarboxylic acid component that becomes a dicarboxylic acid unit, a diamine component that becomes a diamine unit, a catalyst, and, if necessary, a terminal stopper are each mixed in a predetermined amount all at once, heated to 200 to 250 ° C. to obtain a prepolymer, and then solid-phase polymerization is carried out, or polymerization is carried out using a melt extruder. When the final stage of the polymerization is carried out by solid-phase polymerization, it is preferably carried out under reduced pressure or in an inert gas atmosphere. If the polymerization temperature is within the range of 200 to 280 ° C., the polymerization rate is high, the productivity is excellent, and coloring and gelation can be effectively suppressed. When the final stage of the polymerization is carried out by a melt extruder, the polymerization temperature is preferably 370 ° C. or lower, and a polyamide (A) with almost no decomposition and no deterioration can be obtained.

[0034] Examples of the catalyst that can be used in the production of the polyamide (A) include phosphoric acid, phosphorous acid, hypophosphorous acid, their salts or esters, etc. Examples of the salt or ester include salts of phosphoric acid, phosphorous acid or hypophosphorous acid with metals such as potassium, sodium, magnesium, vanadium, calcium, zinc, cobalt, manganese, tin, tungsten, germanium, titanium, and antimony; ammonium salts of phosphoric acid, phosphorous acid or hypophosphorous acid; ethyl esters, isopropyl esters, butyl esters, hexyl esters, isodecyl esters, octadecyl esters, decyl esters, stearyl esters, and phenyl esters of phosphoric acid, phosphorous acid or hypophosphorous acid, etc.

[0035] From the viewpoint of obtaining a molded article excellent in hydrolysis resistance and mechanical strength, the intrinsic viscosity of the polyamide (A) used in the present invention is preferably 0.9 dl / g or more, more preferably 1.0 dl / g or more, still more preferably 1.1 dl / g or more, and even more preferably 1.15 dl / g or more. From the viewpoints of the moldability and fluidity of the polyamide, it is preferably 1.6 dl / g or less, more preferably 1.4 dl / g or less, and still more preferably 1.3 dl / g or less. In the present invention, the intrinsic viscosity of the polyamide (A) is a value measured under the conditions of 30 °C in concentrated sulfuric acid, and specifically, it is a value measured and calculated by the method described in the examples.

[0036] From the viewpoint of obtaining a molded article excellent in hydrolysis resistance and mechanical strength, the melting point of the polyamide (A) used in the present invention is preferably 270 °C or higher, more preferably 280 °C or higher, and still more preferably 290 °C or higher. The melting point of the polyamide (A) can be specifically measured by the method described in the examples.

[0037] <Copper compound powder (B)> The copper compound powder (B) has the effect of preventing the oxidative degradation of the polyamide by copper capturing the radicals generated by the thermal decomposition of the polyamide. In addition, since the copper compound powder (B) uses a powder as the copper compound, a larger amount of the copper compound can be contained in the pellet compared to the case where a solution is used as the copper compound. As a result, the molded body using the pellet has excellent heat resistance. Examples of the copper compound (b1) constituting the copper compound powder (B) include copper salts such as copper halides and copper acetate, and copper halides are preferred. Examples of the copper halide include copper iodide, copper bromide, copper chloride, and copper iodide, with copper iodide, copper bromide, or copper chloride being preferred, copper iodide or copper bromide being more preferred, and copper iodide being even more preferred. The copper halide may be either cuprous halide (copper(I) halide) or cupric halide (copper(II) halide), but cuprous halide is preferred. That is, examples of the copper halide include cuprous iodide, cuprous bromide, cuprous chloride, cupric iodide, cupric bromide, and cupric chloride, with cuprous iodide, cuprous bromide, or cuprous chloride being preferred, cuprous iodide or cuprous bromide being more preferred, and cuprous iodide being even more preferred.

[0038] The content of the copper compound powder (B) is preferably 0.001 to 1.0 part by mass with respect to 100 parts by mass of the polyamide resin. When it is 0.001 part by mass or more, the effect of preventing oxidative degradation of the polyamide can be exhibited well. When it is 1.0 part by mass or less, a decrease in mechanical strength and elongation due to the copper compound powder (B) can be prevented. From these viewpoints, the content of the copper compound powder (B) is more preferably 0.005 to 0.5 part by mass, even more preferably 0.01 to 0.3 part by mass, still more preferably 0.05 to 0.1 part by mass, still more preferably 0.06 to 0.1 part by mass, and still more preferably 0.07 to 0.1 part by mass.

[0039] <Metal halide solution (C)> The metal halide solution (C) contains a metal halide (c1) and a solvent that dissolves the metal halide (c1). The metal halide (c1) helps disperse the copper compound in the polyamide, and has the effect of preventing oxidative degradation over a long period by returning the copper compound to monovalent copper when it changes from monovalent copper to divalent copper due to the anti-thermal aging reaction. In addition, by formulating the metal halide (c1) as a solution, the metal halide will be evenly dispersed in the pellets. As a result, the frequency of contact with the copper compound also dispersed in the pellets increases. Therefore, even when the copper compound changes from monovalent copper to divalent copper due to the anti-thermal aging reaction, the evenly dispersed metal halide (c1) can return the divalent copper to monovalent copper to prevent coloring, and thus it is considered that the appearance will be excellent. Also, by using a solution, the brightness of the resulting pellets increases. Thereby, when coloring the pellets to obtain a molded body, it becomes easier to color it to the desired color, and a molded body with excellent appearance can be obtained.

[0040] The metal constituting the metal halide (c1) is preferably at least one kind of alkali metal, such as potassium and sodium, and preferably potassium. Examples of the halogen constituting the metal halide (c1) include iodine, bromine, chlorine, etc., preferably iodine or bromine, and more preferably iodine. Examples of the metal halide (c1) include potassium iodide, potassium bromide, potassium chloride, sodium iodide, sodium bromide, sodium chloride, etc., preferably potassium iodide, potassium bromide or potassium chloride, and more preferably potassium iodide. Examples of the solvent for dissolving the metal halide (c1) include water, alcohols such as methanol and ethanol, etc., and preferably water.

[0041] The metal halide solution (C) is preferably at least one solution (C1) selected from the group consisting of halogen compounds of alkali metals and halogen compounds of alkaline earth metals. In addition, the metal halide solution (C) is preferably an aqueous solution of a metal halide. The metal halide solution (C) is more preferably an aqueous potassium iodide solution or an aqueous potassium bromide solution.

[0042] From the viewpoints of uniformly dispersing the metal halide in the pellet and improving productivity, the concentration of the metal halide (c1) in the metal halide solution (C) is preferably 1 to 80% by mass, more preferably 10 to 70% by mass, still more preferably 30 to 60% by mass, and even more preferably 40 to 50% by mass. The metal halide solution (C) may contain optional components in addition to the metal halide (c1) and the solvent, but preferably does not contain them. The total content of the metal halide (c1) and the solvent in the metal halide solution (C) is preferably 80% by mass or more, more preferably 90% by mass or more, still more preferably 95% by mass or more, even more preferably 99% by mass or more, for example, 100% by mass.

[0043] The compounding amount of the metal halide (c1) constituting the metal halide solution (C) is preferably 0.01 to 5.0 parts by mass with respect to 100 parts by mass of the polyamide resin. When it is 0.01 part by mass or more, the effects of preventing the oxidative degradation of the polyamide and preventing the coloring caused by the copper compound powder (B) can be exhibited well. When it is 5.0 parts by mass or less, the decrease in mechanical strength and elongation caused by the metal halide (c1) can be prevented. From these viewpoints, the compounding amount of the metal halide solution (C) is more preferably 0.05 to 2.0 parts by mass, still more preferably 0.1 to 1.0 parts by mass, even more preferably 0.3 to 0.7 parts by mass, even more preferably 0.4 to 0.7 parts by mass, even more preferably 0.4 to 0.6 parts by mass, and even more preferably 0.5 to 0.6 parts by mass.

[0044] <Aggregate> The polyamide resin composition pellet according to the present invention contains aggregates. The aggregate is derived from at least one of the copper compound powder (B) and the metal halide solution (C), and is considered to be composed of at least one of, for example, the copper compound (b1) and the metal halide (c1). The average particle diameter of the aggregate is 7 μm or less. Thereby, since the decrease in strength due to the aggregated particles is prevented, a molded article excellent in mechanical strength and elongation characteristics can be manufactured. Further, since the average particle diameter of the aggregate is 7 μm or less, it is uniformly dispersed in the pellet, and the contact frequency with the copper compound powder increases. Thereby, even when the copper changes from monovalent copper to divalent copper by the thermal aging prevention reaction, the divalent copper can be returned to monovalent copper by the uniformly dispersed metal halide to prevent coloring, and thus it is considered that the appearance is excellent. An aggregate having an average particle diameter of 7 μm or less can be produced by blending a metal halide as a metal halide solution into the polyamide resin composition. Further, from the viewpoint of the permeability of the laser used for laser welding, the average particle diameter is preferably 1.0 μm or more. From these viewpoints, the average particle diameter is preferably 1.0 to 7.0 μm, more preferably 1.0 to 6.5 μm, still more preferably 2.0 to 6.0 μm, and even more preferably 2.0 to 5.0 μm.

[0045] Note that as the content of the copper compound and the content of the metal halide in the pellet increase, the average particle diameter of the aggregate tends to increase. In the present invention, by blending the copper compound as the copper compound powder (B) and blending the metal halide as the metal halide solution (C), the average particle diameter of the aggregate can be controlled to 7 μm or less. On the other hand, when the copper compound is blended as an aqueous copper compound solution, since the solubility of the copper compound is low, a sufficient amount of the copper compound cannot be blended. Further, when the content of the copper compound in the aqueous copper compound solution is increased, the copper compound does not dissolve sufficiently and becomes a suspension, and as a result, the average particle diameter of the aggregate increases.

[0046] The average particle diameter of the aggregate is the biaxial average diameter, that is, the number average particle diameter of the major axis among the minor axis and the major axis. Here, the minor axis and the major axis are the shortest diameter and the longest diameter of the elliptical particle, respectively. The measurement of the average particle diameter of the aggregate can be determined by observing 40 particles using an optical microscope. Specifically, the average particle diameter of the aggregate can be measured by the method described in the examples.

[0047] The content of the aggregate is preferably 0.01 to 5.0 parts by mass with respect to 100 parts by mass of the polyamide resin. When it is 0.01 part by mass or more, the effects of preventing the oxidative degradation of the polyamide and preventing the coloring caused by the copper compound powder (B) can be exhibited well. When it is 5.0 parts by mass or less, the decrease in mechanical strength and elongation caused by the metal halide can be prevented. From these viewpoints, the content of the aggregate is more preferably 0.05 to 2.0 parts by mass, still more preferably 0.1 to 1.0 parts by mass, even more preferably 0.4 to 0.7 parts by mass, even more preferably 0.4 to 0.6 parts by mass, and even more preferably 0.5 to 0.6 parts by mass.

[0048] <Optional component> The polyamide resin composition pellets of the present invention may contain additives commonly used in polyamides, such as nucleating agents, mold release agents, lubricants, pigments, dyes, flame retardants, lubricants, plasticizers, reinforcing materials such as glass fibers, antioxidants other than the above, ultraviolet absorbers, etc., within a range not impairing the object of the present invention. The content of the nucleating agent is preferably 0.01 to 1 part by mass with respect to 100 parts by mass of the polyamide (A), more preferably 0.05 to 0.5 part by mass, and still more preferably 0.08 to 0.3 part by mass. The content of the mold release agent is preferably 0.01 to 1 part by mass with respect to 100 parts by mass of the polyamide (A), more preferably 0.05 to 0.5 part by mass, and still more preferably 0.1 to 0.3 part by mass. In the polyamide resin composition pellets, the total content of polyamide (A), copper compound powder (B), and aggregates is preferably 80% by mass or more, more preferably 90% by mass or more, still more preferably 95% by mass or more, and even more preferably 99% by mass or more.

[0049] <Ratio (c1) / (b1) of metal halide (c1) to copper compound (b1)> In the pellets, the ratio (c1) / (b1) of metal halide (c1) to copper compound (b1) is 4 times or more on a mass basis. By being 4 times or more, the brightness of the pellets increases, and it becomes easier to color the pellets to the target color when coloring the pellets, and a molded article with excellent appearance can be produced. Also, from the viewpoint of sufficiently exhibiting the heat aging resistance due to the copper compound, the ratio (c1) / (b1) is preferably 20 times or less. From these viewpoints, the ratio (c1) / (b1) is preferably 4 to 20 times, more preferably 5 to 10 times, still more preferably 5.5 to 8.5 times, even more preferably 5.5 to 7.5 times, and even more preferably 6.2 to 7.5 times. Here, copper compound (b1) means the copper compound constituting copper compound powder (B), and metal halide (c1) means the metal halide in metal halide solution (C) and the metal halide constituting the aggregates. Therefore, the suitable type and content of copper compound (b1) are the same as the suitable type and content of copper compound powder (B). Also, the suitable type and content of metal halide (c1) are the same as the suitable type and content of the metal halide in metal halide solution (C).

[0050] <Physical properties, etc. of polyamide resin composition pellets> The color tone of the polyamide resin composition pellets preferably satisfies the following formula (1). L * ≧74.0 ···(1) In formula (1), L * is the CIE1976 (L * a * b* ) L defined by the color system * is as follows. By satisfying the formula (1), the lightness increases, so that it is easy to color the pellet to the target color when coloring the pellet. From this point of view, L * is preferably 78.0 or more, more preferably 80.0 or more, still more preferably 80.5 or more, and even more preferably 81.0 or more. L * To make L 74.0 or more, it is necessary to obtain a pellet by blending a metal halide as a solution. Further, when the ratio (c1) / (b1) of the metal halide (c1) to the copper compound (b1) in the pellet is increased, L * tends to increase. The color tone of the polyamide resin composition pellet can be specifically measured by the method described in the examples.

[0051] The tensile breaking strength of the polyamide resin composition pellet is preferably 80 MPa or more, more preferably 85 MPa or more, still more preferably 90 MPa or more. The tensile breaking strength of the polyamide resin composition pellet can be specifically measured by the method described in the examples.

[0052] The tensile nominal strain (tensile breaking elongation) of the polyamide resin composition pellet is preferably 8.0% or more, more preferably 11.0% or more, still more preferably 12.0% or more, and even more preferably 13.0% or more. The tensile nominal strain of the polyamide resin composition pellet can be specifically measured by the method described in the examples.

[0053] [Method for producing polyamide resin composition pellet] The method for producing polyamide resin composition pellets according to the present invention is a method for producing polyamide resin composition pellets, which comprises supplying polyamide (A), copper compound powder (B), and metal halide solution (C) to a melt extruder to obtain polyamide resin composition pellets, wherein the pellets contain aggregates, the metal halide solution (C) contains a metal halide (c1) and a solvent for dissolving the metal halide (c1), the ratio (c1) / (B) of the metal halide (c1) to the copper compound powder (B) is 4 times or more on a mass basis, and after supplying the polyamide (A) and the metal halide solution (C) to the melt extruder, the copper compound powder (B) is supplied to the melt extruder.

[0054] Thus, by supplying the polyamide (A) and the metal halide solution (C) to the melt extruder, homogeneously dispersing the metal halide solution (C) in the polyamide (A), and then supplying the copper compound powder (B) to the melt extruder, the metal halide solution (C) will be present at the position where it contacts the copper compound powder (B), so that discoloration of the copper compound is preferably prevented by the metal halide.

[0055] The polyamide (A), copper compound powder (B), metal halide solution (C), and aggregates used in the method for producing polyamide resin composition pellets according to the present invention are as described in the above-described polyamide resin composition pellets.

[0056] The ratio (c1) / (B) of the metal halide (c1) to the copper compound powder (B) is 4 times or more on a mass basis. By being 4 times or more, the brightness of the pellet becomes high, it becomes easy to color the pellet in the targeted color when coloring the pellet, and a molded body with excellent appearance can be manufactured. Further, from the viewpoint of sufficiently exhibiting the heat aging resistance caused by the copper compound, the ratio (c1) / (B) is preferably 20 times or less. From these viewpoints, the ratio (c1) / (B) is preferably 4 to 20 times, more preferably 5 to 10 times, still more preferably 5.5 to 8.5 times, even more preferably 5.5 to 7.5 times, and even more preferably 6.2 to 7.5 times.

[0057] In addition, after supplying the polyamide (A) to the melt extruder, the metal halide solution (C) may be supplied to the melt extruder, or the polyamide (A) and the metal halide solution (C) may be simultaneously supplied to the melt extruder. However, from the viewpoint of preventing discoloration, it is more preferable to supply the metal halide solution (C) to the melt extruder after supplying the polyamide (A) to the melt extruder.

[0058] There is no particular limitation on the melt extruder, and a single-screw extruder, a twin-screw extruder, etc. are preferably adopted. The melt kneading conditions are not particularly limited. For example, a method of melt kneading for about 1 to 30 minutes in a temperature range about 10 to 50 °C higher than the melting point of the polyamide (A) can be mentioned.

[0059] The melt extruder preferably has two or more sample inlets (feed ports), and more preferably has three or more sample inlets. When having two or more sample inlets, after supplying the polyamide (A) and the metal halide solution (C) to the upstream sample inlet to uniformly disperse the metal halide in the polyamide (A), and then supplying the copper compound powder (B) to the downstream sample inlet, the metal halide and the copper compound powder (B) can be brought into good contact with each other. When there are three or more sample inlets, polyamide (A) is supplied to the upstream sample inlet, then a metal halide solution (C) is supplied to the sample inlet downstream of it to homogeneously disperse the metal halide in polyamide (A), and then copper compound powder (B) is supplied to the sample inlet downstream of it, whereby the metal halide and the copper compound powder (B) can be brought into good contact with each other.

[0060] Note that as for polyamide (A) compounded as polyamide resin composition pellets, the whole amount thereof may be supplied from the upstream sample inlet to the melt extruder, but a part thereof may be supplied from the upstream sample inlet to the melt extruder, and the remainder may be supplied from the downstream sample inlet to the melt extruder together with the copper compound powder (B). In this case, the ratio (A-2) / (A-1) of polyamide (A-2) supplied from the downstream sample inlet to the melt extruder together with the copper compound powder (B) to polyamide (A-1) supplied from the upstream sample inlet to the melt extruder is preferably 1 / 99 to 20 / 80, more preferably 5 / 95 to 15 / 85, still more preferably 8 / 92 to 15 / 85.

[0061] The extruder preferably has one or more vent parts. By using such an extruder, decomposition products and volatile components such as the solvent of the metal halide solution (C) can be sucked from the vent part, and the quality of the obtained composition pellets can be improved. The vent part may be an open vent part open to the atmosphere or a vacuum vent part connected to a vacuum pump. For example, in the case of an extruder having an upstream sample inlet for supplying the metal halide solution (C) and a downstream sample inlet for supplying the copper compound powder (B) located downstream of it, an open vent part for exhausting volatile components such as the solvent of the metal halide solution (C) is provided at a position between the upstream sample inlet and the downstream sample inlet of the extruder, and a vacuum vent part may be provided downstream of the downstream sample inlet.

[0062] [Molded body] The molded article according to the present invention is a molded article obtained from the polyamide resin composition pellets. Alternatively, the molded article according to the present invention is a molded article obtained from polyamide resin composition pellets produced by the method for producing the polyamide resin composition pellets. The polyamide resin composition pellets of the present invention can obtain a molded article by being subjected to various molding methods. The molding method of the molded article may be appropriately selected according to the application, but methods such as injection molding method, blow molding method, extrusion molding method, compression molding method, stretching molding method, vacuum molding method, foam molding method, rotational molding method, impregnation method, laser sintering method, and thermal melting lamination method can be adopted. Since the polyamide resin composition pellets of the present invention are excellent in thermal stability in the molten state, they are less likely to be deteriorated during molding, and a molded article of excellent quality with suppressed defects and color tone changes can be obtained.

[0063] [Applications of the Molded Article] Examples of the molded product include films, sheets, tubes, pipes, gears, cams, various housings, rollers, impellers, bearing retainers, spring holders, clutch parts, chain tensioners, tanks, wheels, capacitors, jacks, LED reflectors, and the like. In particular, the molded article of the present invention is optimal for members assumed to be in a high-temperature environment, and can be suitably used for molded products for automotive applications, for example, interior and exterior parts of automobiles, parts in the engine room, cooling system parts, sliding parts, electrical parts, sensors, etc. In addition, it can be used as parts for faucets and plumbing applications, medical instrument applications, and cooking utensil applications under high-temperature environments. Such molded products can be suitably used for housings, thermo units, cartridges, pipes, spindles, filters, fins, valves, propeller shafts, etc. Furthermore, the polyamide resin composition pellets of the present invention can be used for electrical and electronic parts assumed to be in a high-temperature environment. Such molded products can be suitably used for surface mount type connectors, sockets, camera modules, power supply parts, switches, sensors, capacitor seat plates, hard disk parts, relays, resistors, fuse holders, coil bobbins, IC housings, etc. [Example]

[0064] Hereinafter, the present invention will be described in more detail using examples and comparative examples, but the present invention is not limited to the following examples.

[0065] [Measurement of Physical Properties] The measurement of each physical property in the production examples, examples, and comparative examples was carried out according to the methods shown below.

[0066] (Melting Point) The melting point of the polyamide obtained in the production example was measured using a differential scanning calorimeter "DSC7020" manufactured by Hitachi High-Tech Science Corporation. The melting point was measured in accordance with ISO11357-3 (2nd edition 2011). Specifically, in a nitrogen atmosphere, the sample (semi-aromatic polyamide) was heated from 30°C to 340°C at a rate of 10°C / min, held at 340°C for 5 minutes to completely melt the sample, then cooled to 50°C at a rate of 10°C / min and held at 50°C for 5 minutes. When the temperature was raised again to 340°C at a rate of 10°C / min, the peak temperature of the melting peak that appeared was taken as the melting point (°C). When there were multiple melting peaks, the peak temperature of the melting peak on the highest temperature side was taken as the melting point (°C).

[0067] (Preparation of ISO Multipurpose Specimen Type A Dumbbell) Using the pellets obtained in the examples and comparative examples, an injection molding machine (manufactured by Sumitomo Heavy Industries, Ltd., clamping force: 100 tons, screw diameter: 32 mm) was used to mold with a T-runner mold under the conditions of a cylinder temperature of 320°C, a mold temperature of 140°C, and a cycle time of 40 seconds or less to produce an ISO multipurpose specimen type A dumbbell (4 mm thick, total length 170 mm, parallel part length 80 mm, parallel part width 10 mm), which is a molded product of the polyamide resin composition.

[0068] (Intrinsic Viscosity of Polyamide) Using concentrated sulfuric acid as a solvent, the polyamide obtained in the production example was dissolved to a concentration of 0.2 g / dl to prepare a sample solution. Next, the flow-down time of the solvent (concentrated sulfuric acid) and the flow-down time of the sample solution were measured at a temperature of 30°C, and the intrinsic viscosity was determined from the following formula. η inh =[ln(t 1 / t 0 )] / c In the above relational expression, t 0 represents the flow-down time (seconds) of the solvent (concentrated sulfuric acid), t 1 represents the flow-down time (seconds) of the sample solution, and c represents the concentration (g / dl) of the sample (polyamide (A)) in the sample solution.

[0069] (Tensile strength) Using the obtained ISO multi-purpose test piece type A dumbbell (test piece), in accordance with ISO527-1 (2nd edition 2012), a universal material testing machine 5969 (manufactured by Instron Corporation) was used to measure the tensile breaking strength (MPa) and tensile breaking elongation (%) at 23°C. The larger the numerical value of the tensile breaking strength, the higher the mechanical strength of the molded body (test piece). The larger the numerical value of the tensile breaking elongation (%), the better the elongation characteristics of the molded body (test piece). Note that the breaking elongation uses the nominal strain.

[0070] (Color value (L * )) The color value L * of the pellets obtained in each example and comparative example was measured by photographing the pellets under the following apparatus and conditions. It was measured by using the obtained pellets as samples. Measuring device: Colorimeter RAL COLORCATCH NANO manufactured by RAL gGmbH Light source: CIE standard light source D65 Sensor: CCD camera (224×224 pixels) Measurement geometry: 45° / 0° Software: RAL iCOLOURS (version 3.7.2) Equipment used: Software was used on iPhone (registered trademark) 8 (iOS 13.3)

[0071] (Average particle diameter) The pellets obtained in the examples and comparative examples were measured as samples. The surface of the sample was polished with a small grinding machine SP-150 (manufactured by Nippon Microtome Laboratory Co., Ltd.). After polishing with Engis water-resistant abrasive paper and water, polishing was carried out in the order of a combination of Hyprez diamond slurry 9-STD-PC (manufactured by Engis Co., Ltd.) and abrasive paper Hyp9μm (manufactured by Engis Co., Ltd.), a combination of Hyprez diamond slurry 3-STD-PC (manufactured by Engis Co., Ltd.) and abrasive paper Hyp3μm (manufactured by Engis Co., Ltd.), and a combination of Hyprez diamond slurry 1 / 10-STD-PC (manufactured by Engis Co., Ltd.) and abrasive paper Hyp1 / 10μm (manufactured by Engis Co., Ltd.). When changing the abrasive paper and diamond slurry, ultrasonic cleaning was performed and then polishing was carried out with the abrasive paper and diamond slurry under the following conditions. Ten arbitrary locations of the polished pellet were photographed at a magnification of 500 times using an optical microscope Nikon ECLiPSE LV100NPOL (manufactured by Nikon Corporation). The major axis lengths of 40 aggregates confirmed therein were measured in descending order of size, and the number average particle diameter of the average value was calculated and taken as the average particle diameter of the aggregates.

[0072] Production Example 1 [Production of Polyamide] 7562.5 g (45.6 mol) of terephthalic acid, 7296.8 g (46.2 mol) of a mixture of 1,9-nonanediamine and 2-methyl-1,8-octanediamine [80 / 20 (molar ratio)], 140.7 g (1.15 mol) of benzoic acid, 15 g (0.1% by mass based on the total mass of the raw materials) of sodium hypophosphite monohydrate, and 3.75 liters of distilled water were placed in an autoclave with an internal volume of 40 liters and purged with nitrogen. The internal temperature was raised to 220°C over 3 hours. At this time, the pressure in the autoclave increased to 2 MPa. Then, over 4 hours, water vapor was gradually removed and the reaction was carried out while maintaining the pressure at 2 MPa. Next, the pressure was lowered to 1.2 MPa over 30 minutes to obtain a prepolymer. This prepolymer was pulverized and dried at 120°C under reduced pressure for 12 hours. This was then subjected to solid-phase polymerization at 200°C and 13.3 Pa for 2 hours, followed by solid-phase polymerization at 235°C and 13.3 Pa to obtain a white polyamide. The melting point was 300°C and the intrinsic viscosity was 1.18 dL / g.

[0073] Examples 1, 2, 3, Comparative Example 1 As the melt extruder, a twin-screw extruder "TEM-26SX" (manufactured by Toshiba Machine Co., Ltd.) was used. The twin-screw extruder is equipped with 12 barrels connected in series. These 12 barrels are referred to as C1 barrel, C2 barrel, ··· C12 barrel in order from the upstream side. Also, the C1 barrel is provided with an upstream feed port and an upstream hopper, the C4 barrel is provided with a midstream feed port, the C5 barrel is provided with an open vent section, the C8 barrel is provided with a downstream side feed port, and the C11 barrel is provided with a vacuum vent section. 90 parts by mass of polyamide (A) obtained in Production Example 1, 0.2 parts by mass of a mold release agent, and 0.1 parts by mass of a nucleating agent were premixed and fed from the C1 barrel via the upstream hopper of a twin-screw extruder "TEM-26SX". In barrel C4 located after the resin melting zone, an aqueous solution (C) of 45% by mass potassium iodide in the amount shown in Table 1 was fed at the feed rate shown in Table 1 using a liquid addition device "HYSA12" (manufactured by Fuji Techno Industry Co., Ltd.). Degassing was carried out through an open vent installed in barrel C5 downstream of the extruder. 10 parts by mass of polyamide (A) and 0.082 parts by mass of copper iodide powder (B) premixed in barrel C8 further downstream of the extruder were fed from the side feed port. Degassing was carried out through a vacuum vent installed in barrel C11 downstream of the extruder. Melting and kneading were carried out under the condition of a cylinder temperature of 320°C, followed by extrusion, cooling, and cutting to produce pellet-shaped polyamide resin composition pellets. Using the above polyamide resin composition pellets, ISO multi-purpose test piece type A dumbbells (test pieces) for measuring each physical property were prepared by the aforementioned method, and each physical property was measured by the aforementioned method. The results are shown in Table 1.

[0074] Comparative Example 2 Polyamide (A) obtained in Production Example 1, potassium iodide powder, copper iodide powder (B), and other additives were premixed at the ratios shown in Table 1 and fed from the upstream hopper of a twin-screw extruder "TEM-26SS" (manufactured by Toshiba Machine Co., Ltd.). Melting and kneading were carried out under the condition of a cylinder temperature of 320°C, followed by extrusion, cooling, and cutting to produce polyamide resin composition pellets. Using the above polyamide resin composition pellets, ISO multi-purpose test piece type A dumbbells (test pieces) for measuring each physical property were prepared by the aforementioned method, and each physical property was measured by the aforementioned method. The results are shown in Table 1.

[0075] Comparative Example 3 90 parts by mass of the polyamide (A) obtained in Production Example 1, 0.65 parts by mass of potassium iodide powder, 0.2 parts by mass of a release agent, and 0.1 parts by mass of a nucleating agent were premixed and fed from the upstream hopper of a twin-screw extruder "TEM-26SS" (manufactured by Toshiba Machine Co., Ltd.). Further, 10 parts by mass of the premixed polyamide (A) and 0.082 parts by mass of copper iodide powder (B) were fed from the side feed port on the downstream side of the extruder. Melting and kneading were carried out under the condition of a cylinder temperature of 320 °C, followed by extrusion, cooling, and cutting to produce pellet-shaped polyamide resin composition pellets. Using the above polyamide resin composition pellets, ISO multi-purpose test piece type A dumbbells (test pieces) for measuring each physical property were produced by the aforementioned method, and each physical property was measured by the aforementioned method. The results are shown in Table 1.

[0076] In addition, each component shown in Table 1 is as follows. <Polyamide (A)> It is the one obtained by the above Production Example 1. <Copper iodide powder (B)> · Copper(I) iodide powder (B-1): Manufactured by Caliber Chemical, average particle diameter 10 μm <Metal halide> · 45 mass% aqueous potassium iodide (I) solution (C-1): Manufactured by Caliber Chemical · Potassium iodide (I) powder: "Product name: Potassium Iodine" (manufactured by Caliber Chemical), average particle diameter 200 μm

[0077] <Other additives> · Crystal nucleating agent: "TALC ML112" (manufactured by Fuji Talc Co., Ltd.) · Release agent: "Licowax OP" (manufactured by Clariant Japan K.K.)

[0078]

Table 1

[0079] Examples 1 to 3 used an aqueous potassium iodide solution. Since the ratio of copper iodide to potassium iodide was appropriate, the tensile strength, elongation at break, and color tone were good. On the other hand, Comparative Example 1 used an aqueous potassium iodide solution, but since the amount of potassium iodide was small, the tensile strength and elongation at break were good, but the color tone deteriorated. In Comparative Example 2, both potassium iodide and copper iodide were powders and were top-fed. As a result, the aggregates of potassium iodide became large, and the tensile strength and elongation at break decreased. In addition, since copper iodide and potassium iodide were mixed into polyamide at the same time, the color tone deteriorated. In Comparative Example 3, copper iodide was added after adding copper iodide and potassium iodide powders. However, since potassium iodide was not an aqueous solution, the dispersion was poor, and the elongation at break and color tone deteriorated.

Claims

1. Polyamide (A), copper compound powder (B), and metal halide solution (C) are supplied to a melt extruder to obtain polyamide resin composition pellets, and a method for producing polyamide resin composition pellets, wherein the pellets contain aggregates, the polyamide (A) is a polyamide obtained by reacting a mixture containing terephthalic acid, 1,9-nonanediamine, 2-methyl-1,8-octanediamine, and benzoic acid, the copper compound powder (B) contains cuprous iodide, the metal halide solution (C) contains a metal halide (c1) and a solvent for dissolving the metal halide (c1), the metal halide (c1) contains potassium iodide, the ratio (c1) / (B) of the metal halide (c1) to the copper compound powder (B) is 5.5 to 7.5 times by mass, a method for producing polyamide resin composition pellets, wherein after supplying the polyamide (A) and the metal halide solution (C) to a melt extruder, the copper compound powder (B) is supplied to the melt extruder.

2. The method for producing polyamide resin composition pellets according to claim 1, wherein the average particle diameter of the aggregates is 7 μm or less.

3. After supplying the polyamide (A) to a melt extruder, the metal halide solution (C) is supplied to the melt extruder, After supplying the metal halide solution (C) to the melt extruder, the copper compound powder (B) is supplied to the melt extruder, and the method for producing polyamide resin composition pellets according to claim 1 or 2.

4. The method for producing polyamide resin composition pellets according to any one of claims 1 to 3, wherein the metal halide solution (C) is an aqueous metal halide solution.

5. The method for producing polyamide resin composition pellets according to any one of claims 1 to 4, wherein the metal halide solution (C) is an aqueous potassium iodide solution.

6. The method for producing polyamide resin composition pellets according to any one of claims 1 to 5, wherein the melt extruder is provided with two or more sample inlets.

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