Colored polyamide resin composition and molded article thereof

Abstract

A polyamide resin composition containing 45-120 mass parts of an inorganic filler (B), 25-40 mass parts of at least one phosphinic acid salt (C) represented by a specific formula, 2-15 mass parts of a phosphorous acid salt (D), and a coloring agent (E) per 100 mass parts of a specific polyamide (A), in which the sulfur element content is less than 220 mass ppm and ΔE represented by formula (1) is larger than 1, and a molded body thereof. ΔE=[(L* col-L* nat)2+(a* col-a* nat)2+(b* col-b* nat)2]1 / 2 (1) [The symbols in the formula are as defined in the specification.]

Description

[Technical Field]

[0001] The present invention relates to a colored polyamide resin composition and a molded article thereof, and more particularly to a colored halogen-free polyamide resin composition which gives a molded article having excellent flame retardancy, and a molded article thereof. [Background technology]

[0002] Polyamides are widely used in the automotive and electrical / electronic component industries due to their excellent mechanical properties and heat resistance. Surface mounting processes, which offer high component mounting efficiency, are becoming increasingly common in the electrical / electronic component industry. Heat-resistant polyamides, with their high heat resistance and strength, are becoming increasingly popular as the preferred material for forming these components. In recent years, lead-free solders have been adopted for surface mounting processes to reduce environmental impact. However, lead-free solders have a relatively high melting temperature, necessitating a high reflow temperature of approximately 260°C during the surface mounting process. Therefore, heat-resistant polyamides with relatively high melting points are being used to form components for surface mounting processes.

[0003] In the electrical and electronic component industry, flame retardancy is often required for components, often requiring a V-0 rating under the Underwriters Laboratories UL94 standard. Traditionally, heat-resistant polyamides used to form electrical and electronic components have typically been blended with brominated flame retardants. However, with growing environmental awareness in recent years, the use of some raw materials containing harmful elements such as lead and cadmium is being restricted. The use of halogen-containing compounds, such as brominated flame retardants, is also being avoided regardless of the results of evaluations of their safety and actual environmental impact, resulting in a growing demand for halogen-free, flame-retardant polyamides. Several halogen-free flame retardants are known for incorporation into polyamides. However, flame retardants to be incorporated into heat-resistant polyamides with high melting points must not only have high flame retardancy, but also high heat resistance to withstand the high temperatures encountered during melt-kneading in the production of polyamide resin compositions and during molding in the production of molded products. This tendency is particularly pronounced in electrical and electronic components that undergo the reflow process in surface mounting processes. Phosphinates are known as halogen-free flame retardants that have high flame retardancy and heat resistance. For example, resin compositions containing specific semi-aromatic polyamides, polyphenylene ethers, and phosphinates are known (see, for example, Patent Documents 1 and 2). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2007-182550 [Patent Document 2] Japanese Patent Application Laid-Open No. 2007-182551 [Patent Document 3] Japanese Patent Application Laid-Open No. 2015-120891 [Patent Document 4] Japanese Patent Application Laid-Open No. 2010-120983 [Patent Document 5] Japanese Patent Application Laid-Open No. 2014-521765 [Patent Document 6] Japanese Patent Application Laid-Open No. 2016-186080 Summary of the Invention [Problem to be solved by the invention]

[0005] The polyamide resin composition containing the above-mentioned phosphinate salt is sometimes colored and used for automotive parts or electrical / electronic parts. However, molded articles using polyamide resin compositions containing phosphinate salts and having excellent visibility due to coloring have a problem in that the flame retardancy may be reduced. For example, when the thickness of the test piece is 0.15 to 3.0 mm, test pieces using polyamide resin compositions containing phosphinate salts but without a colorant may comply with the UL94V-0 standard, but test pieces using polyamide resin compositions containing phosphinate salts and a colorant may not comply with the UL94V-0 standard.

[0006] On the other hand, Patent Document 3 discloses a flame-retardant thermoplastic resin composition containing polyphenylene ether, a metal phosphinate, and a colorant, but Patent Document 3 makes no mention of the effect of the colorant on flame retardancy. Furthermore, Patent Document 4 discloses a polyamide resin composition containing a metal phosphinate, a specific rubber, melamine polyphosphate as a flame retardant, and a white pigment. This polyamide resin composition contains melamine polyphosphate, which has poor heat resistance, making it difficult to apply to resin compositions used in reflow processes. Furthermore, Patent Document 4 does not mention at all the effect of colorants on flame retardancy. Patent Documents 5 and 6 disclose flame-retardant polyamide compositions with excellent appearance, which contain a flame retardant containing a specific polyamide, a metal phosphinate, and a colorant. However, Patent Documents 5 and 6 also make no mention of the effect of the colorant on flame retardancy.

[0007] Therefore, an object of the present invention is to provide a halogen-free polyamide resin composition that can withstand a reflow process, has excellent flame retardancy, and is excellent in visibility, and a molded article thereof. [Means for solving the problem]

[0008] As a result of intensive research to solve the above problems, the present inventors have conceived the following invention and found that the problems can be solved. That is, the present invention is as follows.

[0009] [1] A polyamide resin composition comprising, relative to 100 parts by mass of polyamide (A) having a melting point of 280°C or higher, 45 to 120 parts by mass of inorganic filler (B), 25 to 40 parts by mass of at least one phosphinate (C) represented by the following formula (I) or the following formula (II), 2 to 15 parts by mass of phosphite (D), and a colorant (E), wherein the sulfur content is less than 220 ppm by mass, and ΔE represented by the following formula (1) is greater than 1. [ka] [ka] [In formula (I) and formula (II), R 1 , R 2 , R 4 and R 5 R each independently represents a linear or branched alkyl group having 1 to 16 carbon atoms. 1 and R 2 and R 4 and R 5 may be bonded to each other to form a ring. 3 represents a linear or branched alkylene group having 1 to 10 carbon atoms, an arylene group having 6 to 10 carbon atoms, an alkylarylene group having 7 to 20 carbon atoms, a cycloalkylene group having 3 to 10 carbon atoms, an aralkylene group having 7 to 10 carbon atoms, or an arylalkylene group having 7 to 20 carbon atoms. M represents calcium, magnesium, aluminum, or zinc. m is an integer of 1 to 4. n is an integer of 1 to 4. x is an integer of 1 to 4. In formula (II), m, x, and n satisfy the relationship mx=2n.] ΔE = (L * col -L * nat ) 2 +(a * col -a* nat ) 2 +(b * col -b * nat ) 2 〕 1 / 2 (1) [In formula (1), ΔE is CIE1976 (L * a * b * ) color difference defined by the color system, and L * col , a * col , and b * col The polyamide resin composition is CIE1976(L * a * b * ) L defined by the color system * , a * , and b * and L * nat , a * nat , and b * nat The polyamide resin composition containing no colorant (E) has the same composition as the polyamide resin composition described above, except that it does not contain the colorant (E). * a * b * ) L defined by the color system * , a * , and b * ] [2] A molded article of the polyamide resin composition described in [1] above. [Effects of the Invention]

[0010] According to the present invention, it is possible to provide a halogen-free polyamide resin composition that can withstand a reflow process, has excellent flame retardancy, and has excellent visibility, and a molded article thereof. DETAILED DESCRIPTION OF THE INVENTION

[0011] The following describes an example of an embodiment of the present invention (hereinafter, sometimes referred to as "the present embodiment"). However, the embodiment described below is merely an example for embodying the technical idea of ​​the present invention, and the present invention is not limited to the following description. In addition, although preferred embodiments are shown in this specification, a combination of two or more of the individual preferred embodiments is also a preferred embodiment. When there are several numerical ranges for matters shown as numerical ranges, the lower limit and upper limit can be selectively combined to form a preferred embodiment. In this specification, when a numerical range is stated as "XX to YY", it means "XX or more and YY or less."

[0012] <Polyamide resin composition> The polyamide resin composition of the present embodiment contains, relative to 100 parts by mass of a specific polyamide (A), 45 to 120 parts by mass of an inorganic filler (B), 25 to 40 parts by mass of at least one phosphinate (C) represented by a specific formula, 2 to 15 parts by mass of a phosphite (D), and a colorant (E), and is characterized by having a sulfur element content of less than 220 ppm by mass and a ΔE represented by the following formula (1) of greater than 1: ΔE = (L * col -L * nat ) 2 +(a * col -a * nat ) 2 +(b * col -b * nat ) 2 〕 1 / 2 (1) [In formula (1), ΔE is CIE1976 (L * a * b * ) color difference defined by the color system, and L * col , a * col , and b * col The polyamide resin composition is CIE1976(L* a * b * ) L defined by the color system * , a * , and b * and L * nat , a * nat , and b * nat The polyamide resin composition containing no colorant (E) has the same composition as the polyamide resin composition described above, except that it does not contain the colorant (E). * a * b * ) L defined by the color system * , a * , and b * ] The polyamide resin composition is a halogen-free polyamide resin composition that can withstand a reflow process, has excellent flame retardancy, and is excellent in visibility. The reason why a molded article of a polyamide resin composition containing a phosphinate and having excellent visibility due to coloring has excellent flame retardancy is not entirely clear, but is thought to be as follows. The main flame retardant mechanism of phosphinates is the formation of a carbonized layer due to polyphosphoric acid produced by the decomposition of the phosphinates during combustion. This carbonized layer suppresses heat conduction and inhibits the thermal decomposition of the resin and the resulting combustion. Furthermore, in the present invention, it is believed that not only the phosphinates but also the phosphites contained in the polyamide resin composition of this embodiment contribute to improved flame retardancy. Specifically, it is believed that the phosphites decompose and foam during combustion, thereby forming a heat insulating layer. This heat insulating layer suppresses heat conduction and inhibits the thermal decomposition of the resin and the resulting combustion. Meanwhile, elemental sulfur is widely used in colorants, for example, to change the electronic state of organic colorants to adjust color development, or as a sulfide in inorganic colorants. Furthermore, elemental sulfur may be mixed in as an impurity during the production of colorants. In addition to colorants, elemental sulfur may also be contained in catalysts and other additives used in the synthesis process of polyamide resins. Considering the above, it is believed that the presence of sulfur element in a polyamide resin composition containing a phosphinate and a phosphite generates sulfur radicals during combustion, and these sulfur radicals deactivate polyphosphoric acid and phosphorous acid. In this case, if the amount of sulfur element is large, it is thought that a sufficient carbonized layer or heat insulating layer cannot be formed, resulting in a decrease in flame retardancy. Therefore, it is believed that even in the case of a polyamide resin composition containing a phosphinate and a colorant, by adjusting the sulfur element content to a specific value, it is possible to provide a molded article having excellent flame retardancy.

[0013] [Polyamide (A)] The polyamide (A) has a melting point of 280°C or higher. The melting point of the polyamide (A) is preferably not less than 285° C., more preferably not less than 295° C. When the melting point of the polyamide (A) is above the above temperature, a molded article of a polyamide resin composition containing the polyamide (A) can maintain sufficient heat resistance even when used in an application where it is exposed to a heating process such as a reflow process.

[0014] The polyamide (A) contains diamine units, and it is preferred that 50 to 100 mol % of the diamine units are aliphatic diamine units having 4 to 18 carbon atoms. Preferably, the polyamide (A) contains dicarboxylic acid units and diamine units, the dicarboxylic acid units being primarily units derived from terephthalic acid, and the diamine units being primarily at least one selected from aliphatic diamines having 4 to 12 carbon atoms. Many of the above polyamides have sufficiently high melting points, and by using these, a polyamide resin composition can be obtained that can give a molded article that can withstand a reflow process. Here, "main component" means that other components may be contained within a range that does not impair the effects of the present invention. "Main component of dicarboxylic acid units" means that they constitute preferably 50 to 100 mol%, more preferably 60 to 100 mol%, and even more preferably 90 to 100 mol% of all dicarboxylic acid units. Furthermore, "main component of diamine units" means that they constitute preferably 50 to 100 mol%, more preferably 60 to 100 mol%, and even more preferably 90 to 100 mol% of all diamine units.

[0015] Examples of dicarboxylic acid units other than units derived from terephthalic acid include structural units derived from aliphatic dicarboxylic acids such as oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, undecanedicarboxylic acid, dodecanedicarboxylic acid, dimethylmalonic acid, 2,2-diethylsuccinic acid, 2,2-dimethylglutaric acid, 2-methyladipic acid, and trimethyladipic acid; alicyclic dicarboxylic acids such as 1,3-cyclopentanedicarboxylic acid, 1,3-cyclohexanedicarboxylic acid, 1,4-cyclohexanedicarboxylic acid, cycloheptanedicarboxylic acid, cyclooctanedicarboxylic acid, and cyclodecanedicarboxylic acid; and aromatic dicarboxylic acids such as isophthalic acid, 1,4-naphthalenedicarboxylic acid, 2,6-naphthalenedicarboxylic acid, 2,7-naphthalenedicarboxylic acid, diphenic acid, 4,4'-biphenyldicarboxylic acid, diphenylmethane-4,4'-dicarboxylic acid, and diphenylsulfone-4,4'-dicarboxylic acid. These units may be of one type or of two or more types. Furthermore, the polyamide may also contain structural units derived from trivalent or higher polycarboxylic acids such as trimellitic acid, trimesic acid, and pyromellitic acid, to the extent that melt molding is possible, within the range that does not impair the effects of the present invention.

[0016] Examples of the aliphatic diamine unit having 4 to 18 carbon atoms include 1,4-butanediamine, 1,5-pentanediamine, 1,6-hexanediamine, 1,7-heptanediamine, 1,8-octanediamine, 1,9-nonanediamine, 1,10-decanediamine, 1,11-undecanediamine, 1,12-dodecanediamine, 1,13-tridecanediamine, 1,14-tetradecanediamine, 1,15-pentadecanediamine, 1,16-hexadecanediamine, 1,17-heptadecanediamine, and 1,18-octadecanediamine. Linear aliphatic diamines; 1-butyl-1,2-ethanediamine, 1,1-dimethyl-1,4-butanediamine, 1-ethyl-1,4-butanediamine, 1,2-dimethyl-1,4-butanediamine, 1,3-dimethyl-1,4-butanediamine, 1,4-dimethyl-1,4-butanediamine, 2,3-dimethyl-1,4-butanediamine, 2-methyl-1,5-pentanediamine, 3-methyl-1,5-pentanediamine, 2,5-dimethyl-1,6-hexanediamine, 2,4-dimethyl-1,6-hexanediamine, 3,3-di Methyl-1,6-hexanediamine, 2,2-dimethyl-1,6-hexanediamine, 2,2,4-trimethyl-1,6-hexanediamine, 2,4,4-trimethyl-1,6-hexanediamine, 2,4-diethyl-1,6-hexanediamine, 2,2-dimethyl-1,7-heptanediamine, 2,3-dimethyl-1,7-heptanediamine, 2,4-dimethyl-1,7-heptanediamine, 2,5-dimethyl-1,7-heptanediamine, 2-methyl-1,8-octanediamine, 3-methyl-1,8-octanediamine, 4- Examples of structural units include those derived from branched-chain aliphatic diamines such as methyl-1,8-octanediamine, 1,3-dimethyl-1,8-octanediamine, 1,4-dimethyl-1,8-octanediamine, 2,4-dimethyl-1,8-octanediamine, 3,4-dimethyl-1,8-octanediamine, 4,5-dimethyl-1,8-octanediamine, 2,2-dimethyl-1,8-octanediamine, 3,3-dimethyl-1,8-octanediamine, 4,4-dimethyl-1,8-octanediamine, and 5-methyl-1,9-nonanediamine. Among these, from the viewpoints of heat resistance sufficient to withstand a reflow process and flame retardancy of a molded article of the polyamide resin composition, structural units derived from at least two selected from 1,8-octanediamine, 2-methyl-1,8-octanediamine, 1,9-nonanediamine, 1,10-decanediamine, 1,11-undecanediamine, and 1,12-dodecanediamine are preferred, and structural units derived from at least two selected from 1,9-nonanediamine, 2-methyl-1,8-octanediamine, and 1,10-decanediamine are more preferred.

[0017] In particular, from the viewpoint of heat resistance sufficient to withstand a reflow process and flame retardancy of a molded article of the polyamide resin composition, it is preferable that the diamine units contain units derived from an aliphatic diamine having 9 carbon atoms, it is more preferable that the diamine units contain at least two types of aliphatic diamines having 9 carbon atoms as main components, and it is even more preferable that the diamine units contain 60 to 100 mol % of 1,9-nonanediamine units and 2-methyl-1,8-octanediamine units. When the diamine units contain 60 to 100 mol % in total of structural units derived from 1,9-nonanediamine and structural units derived from 2-methyl-1,8-octanediamine, the molar ratio of structural units derived from 1,9-nonanediamine to structural units derived from 2-methyl-1,8-octanediamine (structural units derived from 1,9-nonanediamine:structural units derived from 2-methyl-1,8-octanediamine) is preferably in the range of 30:70 to 95:5, more preferably in the range of 50:50 to 90:10, and even more preferably in the range of 70:30 to 90:10. This molar ratio range is particularly suitable for preventing the melting point of the polyamide (A) from becoming too low and for achieving a temperature that can withstand the reflow process.

[0018] The diamine units in the polyamide (A) may contain diamine units other than aliphatic diamine units having 4 to 18 carbon atoms, provided that the effects of the present invention are not impaired. Examples of such diamine units include structural units derived from aliphatic diamines such as ethylenediamine, 1,2-propanediamine, and 1,3-propanediamine; alicyclic diamines such as cyclohexanediamine, methylcyclohexanediamine, isophoronediamine, norbornanedimethylamine, and tricyclodecanedimethyldiamine; and aromatic diamines such as p-phenylenediamine, m-phenylenediamine, p-xylylenediamine, m-xylylenediamine, 4,4'-diaminodiphenylmethane, 4,4'-diaminodiphenylsulfone, and 4,4'-diaminodiphenylether. These units may be of one type or two or more types.

[0019] The polyamide (A) may contain an aminocarboxylic acid unit. Examples of the aminocarboxylic acid unit include units derived from lactams such as caprolactam and lauryllactam, and aminocarboxylic acids such as 11-aminoundecanoic acid and 12-aminododecanoic acid. The content of the aminocarboxylic acid unit in the polyamide is preferably 40 mol% or less, and more preferably 20 mol% or less, relative to 100 mol% of the total of the dicarboxylic acid units and diamine units in the polyamide.

[0020] The polyamide (A) may contain units derived from a terminal blocking agent, and the amount of the units derived from the terminal blocking agent is preferably 1.0 to 10 mol %, more preferably 2.0 to 7.5 mol %, and even more preferably 2.5 to 6.5 mol %, based on the diamine units. The units derived from the terminal blocking agent can be adjusted to the desired range by adding the terminal blocking agent to the diamine when the polymerization raw materials are charged. Note that, taking into consideration the volatilization of the monomer components during polymerization, it is desirable to finely adjust the amount of the terminal blocking agent added when the polymerization raw materials are charged so that the desired amount of units derived from the terminal blocking agent is introduced into the resulting resin. As a method for determining the content of units derived from the end-capping agent in the polyamide (A), for example, as disclosed in JP-A-07-228690, a method is used in which the solution viscosity is measured, the total amount of end groups is calculated from the relational equation between the viscosity and the number average molecular weight, and the amount of amino groups and the amount of carboxyl groups determined by titration are subtracted from the total amount of end groups, or 1 1 H-NMR is used to determine the concentration based on the integral values ​​of the signals corresponding to the diamine unit and the unit derived from the end-capping agent.

[0021] As the terminal blocking agent, a monofunctional compound having reactivity with a terminal amino group or a terminal carboxyl group can be used. Specific examples include monocarboxylic acids, acid anhydrides, monoisocyanates, monoacid halides, monoesters, monoalcohols, and monoamines. From the viewpoints of reactivity and the stability of the blocked terminals, monocarboxylic acids are preferred as terminal blocking agents for terminal amino groups, and monoamines are preferred as terminal blocking agents for terminal carboxyl groups. Furthermore, from the viewpoints of ease of handling, monocarboxylic acids are more preferred as terminal blocking agents.

[0022] The monocarboxylic acid used as the end-capping agent is not particularly limited as long as it is reactive with an amino group, and examples thereof 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 cyclopentanecarboxylic acid and cyclohexanecarboxylic acid; aromatic monocarboxylic acids such as benzoic acid, toluic acid, α-naphthalenecarboxylic acid, β-naphthalenecarboxylic acid, methylnaphthalenecarboxylic acid, and phenylacetic acid; and mixtures thereof. Among these, at least one selected from the group consisting of 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 is preferred from the standpoints of reactivity, stability of the blocked end, cost, and the like.

[0023] The monoamine used as the terminal blocking agent is not particularly limited as long as it is reactive with a carboxyl group, and examples thereof include aliphatic monoamines such as methylamine, ethylamine, propylamine, butylamine, hexylamine, octylamine, decylamine, stearylamine, dimethylamine, diethylamine, dipropylamine, and dibutylamine; alicyclic monoamines such as cyclohexylamine and dicyclohexylamine; aromatic monoamines such as aniline, toluidine, diphenylamine, and naphthylamine; and any mixtures thereof. Among these, at least one selected from the group consisting of butylamine, hexylamine, octylamine, decylamine, stearylamine, cyclohexylamine, and aniline is preferred in terms of reactivity, high boiling point, stability of blocked terminals, cost, and the like.

[0024] The polyamide (A) can be produced by any known method for producing polyamides, such as a solution polymerization method or an interfacial polymerization method using an acid chloride and a diamine as raw materials, a melt polymerization method using a dicarboxylic acid and a diamine as raw materials, a solid-state polymerization method, or a melt extrusion polymerization method.

[0025] Polyamide (A) can be produced, for example, by first preparing a nylon salt by adding diamine, dicarboxylic acid, and, if necessary, a catalyst and end-capping agent all at once, followed by heat polymerization at a temperature of 200 to 250°C to form a prepolymer, which is then further solid-state polymerized or polymerized using a melt extruder. When the final stage of polymerization is carried out by solid-state polymerization, it is preferably carried out under reduced pressure or in an inert gas flow. A polymerization temperature within the range of 200 to 280°C provides a high polymerization rate, excellent productivity, and effective suppression of coloration and gelation. When the final stage of polymerization is carried out using a melt extruder, the polymerization temperature is preferably 370°C or less, and polymerization under such conditions results in a polyamide with almost no decomposition and little deterioration.

[0026] Examples of catalysts that can be used in producing the polyamide (A) include phosphoric acid, phosphorous acid, hypophosphorous acid, salts or esters thereof, etc. Examples of the salts or esters include salts of phosphoric acid, phosphorous acid, or hypophosphorous acid with metals such as potassium, sodium, magnesium, vanadium, calcium, zinc, cobalt, manganese, tin, tungsten, germanium, titanium, and antimony; ammonium salts of phosphoric acid, phosphorous acid, or hypophosphorous acid; and ethyl 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.

[0027] The polyamide (A) may include any of crystalline polyamide, amorphous polyamide, and a mixture thereof, as long as the effects of the present invention are not impaired.

[0028] Examples of the crystalline polyamide include polycaproamide (polyamide 6), polyhexamethylene adipamide (polyamide 66), polytetramethylene adipamide (polyamide 46), polyhexamethylene sebacamide (polyamide 610), polyhexamethylene dodecamide (polyamide 612), polyundecamethylene adipamide (polyamide 116), polybis(4-aminocyclohexyl)methanedodecamide (polyamide PACM12), polybis(3-methyl-4-aminocyclohexyl)methanedodecamide (polyamide dimethyl PACM12), polyundecamethylene terephthalamide (polyamide 11T), and polyundecamethylene terephthalamide (polyamide 11T). Examples of crystalline polyamides include methylene hexahydroterephthalamide (polyamide 11T(H)), polyundecamide (polyamide 11), polydodecamide (polyamide 12), polytrimethylhexamethylene terephthalamide (polyamide TMDT), polymetaxylylene adipamide (polyamide MXD6), polyhexamethylene terephthalamide (polyamide 6T), polyhexamethylene isophthalamide (polyamide 6I), a copolymer of polyamide 6I and polyamide 6T (polyamide 6I / 6T), and a copolymer of polyamide 6T and polyundecaneamide (polyamide 11) (polyamide 6T / 11), as well as copolymers and mixtures thereof. The crystalline polyamides also include those in which the benzene rings of terephthalic acid and / or isophthalic acid are substituted with alkyl groups or halogen atoms. The crystalline polyamides may be used singly or in combination.

[0029] Examples of the amorphous polyamide include a polycondensate of terephthalic acid / isophthalic acid / 1,6-hexanediamine, a polycondensate of terephthalic acid / isophthalic acid / 1,6-hexanediamine / bis(3-methyl-4-aminocyclohexyl)methane, a polycondensate of terephthalic acid / 2,2,4-trimethyl-1,6-hexanediamine / 2,4,4-trimethyl-1,6-hexanediamine, a polycondensate of isophthalic acid / bis(3-methyl-4-aminocyclohexyl)methane / ω-laurolactam, a polycondensate of isophthalic acid / 2,2,4-trimethyl-1,6-hexanediamine / 2,4,4-trimethyl-1,6-hexanediamine, and a polycondensate of terephthalic acid / isophthalic acid / 2,2,4-trimethyl-1,6-hexanediamine / 2,4,4-trimethyl-1,6-hexanediamine. The amorphous polyamide also includes those in which the benzene ring of terephthalic acid and / or isophthalic acid is substituted with an alkyl group or a halogen atom. One type of amorphous polyamide may be used alone, or two or more types may be used in combination.

[0030] [Inorganic filler (B)] Examples of the inorganic filler (B) include carbon nanotubes, fullerenes, talc, wollastonite, zeolite, sericite, mica, kaolin, clay, pyrophyllite, silica, bentonite, alumina silicate, silicon oxide, magnesium oxide, alumina, magnesium carbonate, dolomite, calcium sulfate, calcium hydroxide, magnesium hydroxide, aluminum hydroxide, milled fiber, glass powder, ceramic beads, boron nitride, silicon carbide, various clay minerals such as halloysite and vermiculite, glass fiber, etc. These inorganic fillers may be used alone or in combination of two or more. From the viewpoint of the molding processability of the polyamide resin composition and the mechanical strength of molded articles of the polyamide resin composition, the inorganic filler (B) is preferably at least one selected from glass fibers having a circular cross section and glass fibers having a non-circular cross section (hereinafter, these may be simply abbreviated as glass fibers).

[0031] The cross-sectional shape of a glass fiber having a circular cross section is, for example, a perfect circle or an approximately circle. The cross-sectional shape of a glass fiber having a non-circular cross section is, for example, a cocoon shape with a narrowed central portion in the longitudinal direction of the cross section, an oval shape with a portion that is approximately parallel to the center of gravity of the cross section at a symmetrical position, or an ellipse.

[0032] Furthermore, from the viewpoint of the molding processability of the polyamide resin composition and the mechanical strength of molded articles of the polyamide resin composition, the inorganic filler (B) is preferably glass fiber having a circular cross section and glass fiber having a non-circular cross section. When the inorganic filler (B) is a glass fiber having a circular cross section and a glass fiber having a noncircular cross section, the circumferential length of the cross section of the glass fiber having a noncircular cross section is preferably 1.05 to 1.8 times the circumferential length of the glass fiber having a circular cross section with the same cross-sectional area as the glass fiber having a noncircular cross section. When the inorganic filler (B) is a glass fiber having a circular cross section and a glass fiber having a noncircular cross section, the content ratio thereof is not particularly limited, but the mass ratio of the glass fiber having a circular cross section / the glass fiber having a noncircular cross section is preferably 20 / 80 to 80 / 20, more preferably 30 / 70 to 60 / 40, and even more preferably 30 / 70 to 50 / 50.

[0033] The average fiber length of the glass fibers is preferably 1.0 to 10 mm, more preferably 1.0 to 7.0 mm, and even more preferably 2.0 to 4.0 mm. The average fiber diameter of the glass fibers is preferably from 6 to 20 μm, more preferably from 7 to 16 μm, and even more preferably from 8 to 14 μm, from the viewpoints of flame retardancy, mechanical strength, and appearance of a molded article of the polyamide resin composition. The average fiber length and average fiber diameter of the glass fibers can be determined by measuring the fiber length and fiber diameter of 400 arbitrarily selected glass fibers by image analysis using an electron microscope, and calculating the weight average value of each.

[0034] The polyamide resin composition contains 45 to 120 parts by mass of inorganic filler (B) per 100 parts by mass of polyamide (A). When the content of inorganic filler (B) is 45 parts by mass or more, a molded article of the polyamide resin composition has sufficient strength, and is strong enough to withstand practical use in connectors and the like. When the content is 120 parts by mass or less, the flowability of the polyamide resin composition is good, resulting in excellent moldability and compound productivity. The content of inorganic filler (B) is preferably 48 parts by mass or more, more preferably 50 parts by mass or more. The content of inorganic filler (B) is preferably 100 parts by mass or less, more preferably 80 parts by mass or less.

[0035] [Phosphinate (C)] The polyamide resin composition contains 25 to 40 parts by mass of the phosphinate (C) per 100 parts by mass of the polyamide (A), thereby making it possible to provide a halogen-free polyamide resin composition that gives a molded article having excellent flame retardancy. The phosphinate (C) is at least one type represented by the following formula (I) or the following formula (II). That is, the phosphinate (C) is a phosphinate represented by the following formula (I), a diphosphinate represented by the following formula (II), or a mixture thereof.

[0036] [ka]

[0037] [ka]

[0038] In formula (I) and formula (II), R 1 , R 2 , R 4 and R 5R each independently represents a straight-chain or branched-chain alkyl group having 1 to 16 carbon atoms. Among these, an alkyl group having 1 to 8 carbon atoms is preferred, with a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, a tert-butyl group, an n-pentyl group, or an n-octyl group being more preferred, and an ethyl group being even more preferred. 1 and R 2 and R 4 and R 5 may be bonded to each other to form a ring. R 3 represents a linear or branched alkylene group having 1 to 10 carbon atoms, an arylene group having 6 to 10 carbon atoms, an alkylarylene group having 7 to 20 carbon atoms, a cycloalkylene group having 3 to 10 carbon atoms, an aralkylene group having 7 to 10 carbon atoms, or an arylalkylene group having 7 to 20 carbon atoms. Examples of the linear or branched alkylene group having 1 to 10 carbon atoms include a methylene group, an ethylene group, an n-propylene group, an isopropylene group, an isopropylidene group, an n-butylene group, a tert-butylene group, an n-pentylene group, and an n-octylene group. Examples of the arylene group having 6 to 10 carbon atoms include a phenylene group and a naphthylene group. Examples of the alkylarylene group having 7 to 10 carbon atoms include a methylphenylene group, an ethylphenylene group, a tert-butylphenylene group, a methylnaphthylene group, an ethylnaphthylene group, and a tert-butylnaphthylene group. Examples of the cycloalkylene group having 3 to 10 carbon atoms include a cyclohexylene group and a cyclohexadimethylene group. Examples of the aralkylene group having 7 to 10 carbon atoms include a phenylenemethylene group, a phenyleneethylene group, and a xylylene group. Examples of the arylalkylene group having 7 to 20 carbon atoms include a phenylmethylene group, a phenylethylene group, a phenylpropylene group, and a phenylbutylene group. M represents calcium, aluminum, magnesium, or zinc, with aluminum and zinc being preferred, and aluminum being more preferred. m is an integer of 1 to 4. n is an integer of 1 to 4. x is an integer of 1 to 4. In formula (II), m, x, and n satisfy the relation mx=2n (i.e., the product of m and x is equal to the product of 2 and n).

[0039] Examples of phosphinic acids constituting the phosphinic acid salt (C) include dimethylphosphinic acid, ethylmethylphosphinic acid, diethylphosphinic acid, methyl-n-propylphosphinic acid, isobutylmethylphosphinic acid, octylmethylphosphinic acid, methylphenylphosphinic acid, and diphenylphosphinic acid, and among these, diethylphosphinic acid is preferred.

[0040] Specific examples of the phosphinate salt represented by the above formula (I) include calcium dimethylphosphinate, magnesium dimethylphosphinate, aluminum dimethylphosphinate, zinc dimethylphosphinate, calcium ethylmethylphosphinate, magnesium ethylmethylphosphinate, aluminum ethylmethylphosphinate, zinc ethylmethylphosphinate, calcium diethylphosphinate, magnesium diethylphosphinate, aluminum diethylphosphinate, zinc diethylphosphinate, calcium methyl-n-propylphosphinate, magnesium methyl-n-propylphosphinate, aluminum methyl-n-propylphosphinate, zinc methyl-n-propylphosphinate, calcium methylphenylphosphinate, magnesium methylphenylphosphinate, aluminum methylphenylphosphinate, zinc methylphenylphosphinate, calcium diphenylphosphinate, magnesium diphenylphosphinate, aluminum diphenylphosphinate, and zinc diphenylphosphinate.

[0041] Examples of diphosphinic acids constituting the diphosphinic salt include methanedi(methylphosphinic acid) and benzene-1,4-di(methylphosphinic acid). Specific examples of the diphosphinate represented by the above formula (II) include calcium methanedi(methylphosphinate), magnesium methanedi(methylphosphinate), aluminum methanedi(methylphosphinate), zinc methanedi(methylphosphinate), calcium benzene-1,4-di(methylphosphinate), magnesium benzene-1,4-di(methylphosphinate), aluminum benzene-1,4-di(methylphosphinate), and zinc benzene-1,4-di(methylphosphinate). The phosphinate (C) may be used alone or in combination of two or more kinds.

[0042] As the phosphinate (C), aluminum diethylphosphinate, zinc diethylphosphinate, aluminum methanedi(methylphosphinate), and zinc methanedi(methylphosphinate) are preferred from the viewpoint of even better flame retardancy, with aluminum diethylphosphinate being more preferred.

[0043] From the viewpoints of flame retardancy, mechanical strength, and appearance of a molded article of the polyamide resin composition, the number average particle diameter of the phosphinate (C) is preferably 100 μm or less, more preferably 50 μm or less, and even more preferably 40 μm or less. The lower limit of the number average particle diameter is preferably 1 μm or more, more preferably 5 μm or more, and even more preferably 10 μm or more. By using a powder having a number average particle diameter within the above range, not only can higher flame retardancy be achieved, but also the mechanical strength of the resulting molded article can be increased. The number average particle size is the particle size value at 50% cumulative weight when particle size distribution is measured using a particle size distribution measuring device such as a laser scattering particle size distribution analyzer.

[0044] The polyamide resin composition contains 25 to 40 parts by mass of phosphinate (C) per 100 parts by mass of polyamide (A). When the content of phosphinate (C) is 25 parts by mass or more, a molded article of the polyamide resin composition has excellent flame retardancy. When the content is 40 parts by mass or less, the polyamide resin composition has excellent moldability, and a molded article of the polyamide resin composition has excellent mechanical strength. The content of phosphinate (C) is preferably 26 parts by mass or more, more preferably 27 parts by mass or more. The content of phosphinate (C) is preferably 38 parts by mass or less, more preferably 35 parts by mass or less.

[0045] [Phosphite (D)] The polyamide resin composition contains 2 to 15 parts by mass of the phosphite (D) per 100 parts by mass of the polyamide (A), thereby exhibiting excellent flame retardancy and improving the melt-kneading and molding processability of the polyamide resin composition. The phosphites (D) are not particularly limited, but examples thereof include sodium phosphite, potassium phosphite, calcium phosphite, zinc phosphite, ammonium phosphite, aluminum phosphite, and aluminum hydrogen phosphite. From the viewpoint of exhibiting even more excellent flame retardancy, aluminum phosphite and aluminum hydrogen phosphite are preferred. One type of phosphites (D) may be used alone, or multiple types may be used in combination.

[0046] The polyamide resin composition contains 2 to 15 parts by mass of phosphite (D) per 100 parts by mass of polyamide (A). When the content of phosphite (D) is 2 parts by mass or more, a molded article of the polyamide resin composition has excellent flame retardancy. When the content is 15 parts by mass or less, the polyamide resin composition has excellent moldability, and a molded article of the polyamide resin composition has excellent mechanical strength. The content of phosphite (D) is preferably 2.5 parts by mass or more, more preferably 3 parts by mass or more. The content of phosphite (D) is preferably 13 parts by mass or less, more preferably 10 parts by mass or less.

[0047] In the polyamide resin composition, the total content of the phosphinate (C) and the phosphite (D) is preferably 16 to 25% by mass relative to 100% by mass of the polyamide resin composition. When the total content of the phosphinate (C) and the phosphite (D) is 16% by mass or more, a molded article of the polyamide resin composition has excellent flame retardancy. When the total content is 25% by mass or less, the polyamide resin composition has excellent moldability, and a molded article of the polyamide resin composition has excellent mechanical strength. The total content is preferably 16.5% by mass or more, more preferably 17% by mass or more. The total content is preferably 23% by mass or less, more preferably 22.5% by mass or less.

[0048] In the polyamide resin composition, the mass ratio (C) / (D) of the phosphinate (C) to the phosphite (D) is preferably 70 / 30 to 94 / 6. When the mass ratio is within the above range, a molded article of the polyamide resin composition has excellent flame retardancy. The mass ratio is preferably 75 / 25 to 93 / 7, more preferably 80 / 20 to 92 / 8.

[0049] [Colorant (E)] By adding a colorant (E) to the polyamide resin composition, various colors can be produced, and visibility and decorativeness can be imparted. The colorant (E) is not particularly limited, but examples thereof include organic colorants such as organic dyes and organic pigments, and inorganic colorants such as inorganic pigments. Note that the colorant (E) does not include carbon black. In one embodiment of the present invention, the colorant (E) contains an organic colorant. The colorant (E) may be an organic colorant. In another embodiment of the present invention, the colorant (E) contains an inorganic colorant. The colorant (E) may be an inorganic colorant.

[0050] Examples of organic dyes include anthraquinone dyes, perinone dyes, anthrapyridone dyes, methine dyes, azine dyes, azo dyes, azomethine dyes, phthalocyanine dyes, quinoneimine dyes, quinoline dyes, nitro dyes, indigo dyes, and oxazine dyes. Among these, from the viewpoints of heat resistance, color development, and compatibility sufficient to withstand the reflow process, anthraquinone dyes, perinone dyes, anthrapyridone dyes, and phthalocyanine dyes are preferred, and anthraquinone dyes, perinone dyes, and anthrapyridone dyes are more preferred. Specific examples of anthraquinone dyes include Solvent Red 169, Solvent Red 172, Solvent Orange 63, Solvent Blue 101, Solvent Blue 102, and Solvent Yellow 98. Specific examples of perinone dyes include Solvent Red 179. Specific examples of anthrapyridone dyes include Solvent Red 52. Specific examples of azine dyes include nigrosine compounds such as Solvent Black 5. Specific examples of phthalocyanine dyes include Solvent Blue 38. Among these, from the viewpoint of flame retardancy of a molded article of the polyamide resin composition, Solvent Red 52, Solvent Red 169, Solvent Red 172, Solvent Red 179, and Solvent Blue 101 are preferred, and Solvent Red 52 and Solvent Red 179 are more preferred.

[0051] Examples of organic pigments include azo pigments such as azo lake pigments, insoluble monoazo pigments, insoluble disazo pigments, and chelate azo pigments, phthalocyanine pigments, perylene pigments, perinone pigments, anthraquinone pigments, quinacridone pigments, dioxazine pigments, thioindigo pigments, isoindolinone pigments, quinophthalone pigments, diketopyrrolopyrrole pigments, benzimidazolone pigments, and threne pigments. Among these, azo pigments and phthalocyanine pigments are preferred, and phthalocyanine pigments are more preferred, from the viewpoints of heat resistance that can withstand the reflow process, color development, and compatibility. A specific example of the phthalocyanine pigment is Pigment Blue 15, and Pigment Blue 15 is preferred from the viewpoint of the flame retardancy of molded articles of the polyamide resin composition.

[0052] The content of the organic colorant in the colorant (E) is preferably 0.01 to 100% by mass, more preferably 1 to 100% by mass, from the viewpoint of obtaining a polyamide resin composition with excellent visibility.

[0053] Examples of inorganic pigments include metal oxides such as titanium oxide (TiO, TiO, TiO), zinc oxide (PbO), iron oxide (FeO), antimony oxide, and zirconium oxide; ultramarine (Pigment Blue 29); zinc sulfide, zinc phosphate, barium sulfate, manganese phosphate, cobalt aluminate, cobalt stannate, cobalt zincate, antimony oxide, antimony sulfide, cerium sulfide, lanthanum sulfide, chromium oxide, zinc chromate; and composite metal oxides containing multiple oxides of nickel, bismuth, vanadium, molybdenum, cadmium, titanium, zinc, manganese, cobalt, iron, chromium, antimony, magnesium, and aluminum. Specific examples of composite metal oxides include Pigment Yellow 53, Pigment Green 50, Pigment Brown 24, Pigment Blue 28, and Pigment Blue 36. Among these, metal oxides and composite metal oxides are preferred, and from the viewpoint of flame retardancy of molded articles of the polyamide resin composition, titanium oxide (TiO, Ti2O3, TiO2), iron oxide (Fe2O3), Pigment Yellow 53, Pigment Green 50, and Pigment Brown 24 are more preferred.

[0054] The content of the inorganic colorant in the colorant (E) is preferably 20 to 100 mass %, more preferably 30 to 100 mass %, and even more preferably 50 to 100 mass %, from the viewpoint of obtaining a polyamide resin composition with excellent visibility.

[0055] The colorant (E) may be used alone or in combination of two or more types, but from the viewpoint of providing a polyamide resin composition with a wide range of colors, the colorant (E) preferably contains an organic colorant and an inorganic colorant. When the colorant (E) contains an organic colorant and an inorganic colorant, the weight ratio of the organic colorant to the inorganic colorant is preferably 1 / 1 to 1 / 30, more preferably 1 / 1 to 1 / 15.

[0056] The colorant (E) may be used in any form of powder, liquid, or masterbatch. Furthermore, to improve dispersibility, wax may be added or the colorant may be kneaded in advance.

[0057] From the viewpoint of the flame retardancy, color development, and mechanical strength of a molded product of the polyamide resin composition, the content of the colorant (E) is preferably 0.001 to 5.0 mass%, more preferably 0.01 to 3.0 mass%, relative to 100 mass% of the polyamide resin composition if it is an organic colorant, and preferably 0.01 to 5.0 mass%, more preferably 0.05 to 5.0 mass%, relative to 100 mass% of the polyamide resin composition if it is an inorganic colorant.

[0058] [Other ingredients] The polyamide resin composition may contain other components such as a resin other than the polyamide (A), an antioxidant, and a mold release agent, as long as the effects of the present invention are not impaired. Examples of resins other than polyamide (A) include polycarbonate; modified polyphenylene ether; polyphenylene oxide; polyacetal; polyphenylene sulfide (PPS); polysulfone; polyethersulfone; polysulfone; polyarylate; cyclic polyolefin; polyetherimide; syndiotactic polystyrene; brominated polystyrene; polyamideimide; polyimide; liquid crystal polymers such as aromatic polyesters and aromatic polyesteramides; polyaminobismaleimide; aromatic polyetherketones such as polyetheretherketone and polyetherketone. Examples of antioxidants include hindered phenol compounds, phosphorus compounds, lactone compounds, and hydroxyl compounds. Examples of the release agent include silicone-based, fluorine-based, long-chain alkyl-based, and fatty acid amide-based agents.

[0059] The polyamide resin composition may further contain other components, as necessary, such as a heat stabilizer, a light stabilizer, a styrene-maleic anhydride copolymer (SMA), a lubricant, a nucleating agent, a crystallization retarder, a hydrolysis inhibitor, an antistatic agent, a radical inhibitor, a matting agent, an ultraviolet absorber, an anti-drip agent, and an agent for imparting sliding properties. The content of other components in the polyamide resin composition may be within a range that does not impair the effects of the present invention, but from the viewpoint of the flame retardancy of a molded article of the polyamide resin composition, it is preferably 10% by mass or less, more preferably 5% by mass or less.

[0060] [Sulfur element content] The sulfur element content in the polyamide resin composition of the present invention is less than 220 ppm by mass. From the viewpoint of flame retardancy of a molded article of the polyamide resin composition, the sulfur element content in the polyamide resin composition is preferably less than 210 ppm by mass, more preferably less than 200 ppm by mass. Furthermore, from the viewpoint of ease of production, the sulfur element content in the polyamide resin composition is preferably 20 ppm by mass or more, more preferably 50 ppm by mass or more, and even more preferably 70 ppm by mass or more.

[0061] The total content of the polyamide (A), inorganic filler (B), phosphinate (C), phosphite (D), and colorant (E) is preferably 90 to 99.9 mass%, more preferably 95 to 99.9 mass%, and even more preferably 95 to 99.7 mass%, based on 100 mass% of the polyamide resin composition. If the total content is within the above range, the polyamide resin composition is suitable for providing a molded article having superior flame retardancy.

[0062] Considering that the polyamide resin composition is used as a connector or structural part for automobiles or electrical / electronic parts, the strength of the polyamide resin composition is such that the tensile breaking strength is 80 MPa or more, preferably 90 MPa or more, and more preferably 100 MPa or more in a tensile test according to ISO 527.

[0063] The polyamide resin composition of the present invention has a ΔE represented by the following formula (1) that is greater than 1, and has excellent visibility when ΔE is greater than 1. Furthermore, the inorganic filler (B) and colorant (E) of the polyamide resin composition of the present invention can be selected so as to satisfy this requirement. ΔE = (L * col -L * nat ) 2 +(a * col -a * nat ) 2 +(b * col -b * nat ) 2 〕 1 / 2 (1) In equation (1), ΔE is the CIE 1976 (L * a * b * ) color difference defined by the color system. L * col , a * col , and b * col The polyamide resin composition of the present invention is * a * b *) L defined by the color system * , a * , and b * That is, the polyamide resin composition of the present invention satisfies CIE1976(L * a * b * ) L defined by the color system * L * col Yes, a * A * col and b * Ga b * col is. L * nat , a * nat , and b * nat The polyamide resin composition containing no colorant (E) has the same composition as the polyamide resin composition described above, except that it does not contain the colorant (E). * a * b * ) L defined by the color system * , a * , and b * That is, the CIE1976 (L) of a colorant-free polyamide resin composition which has the same composition as the polyamide resin composition except that it does not contain the colorant (E) is * a * b * ) L defined by the color system * L * nat Yes, a * A * nat and b * Ga b * nat is.

[0064] In the polyamide resin composition of the present invention, ΔE represented by formula (1) is preferably greater than 3, more preferably greater than 10, and even more preferably greater than 30, from the viewpoint of improving visibility.

[0065] [Method of producing polyamide resin composition] The method for producing the polyamide resin composition is not particularly limited, and known methods can be used. For example, the polyamide resin composition can be produced by melt-kneading a mixture obtained by dry-blending the polyamide (A), the inorganic filler (B), the phosphinate (C), the phosphite (D), the colorant (E), and other components blended as needed, so that the resulting polyamide resin composition contains 100 parts by mass of polyamide (A) having a melting point of 280°C or higher, 45 to 120 parts by mass of inorganic filler (B), 25 to 40 parts by mass of at least one phosphinate (C) represented by the formula (I) or (II), 2 to 15 parts by mass of phosphite (D), and colorant (E), has a sulfur element content of less than 220 ppm by mass, and has a ΔE represented by the formula (1) of greater than 1. The melt-kneading method is not particularly limited, and any method capable of uniformly mixing the above components can be preferably used. For example, a single-screw extruder, a twin-screw extruder, a kneader, a Banbury mixer, etc. are preferred, and a twin-screw extruder is more preferred from the viewpoints of good dispersibility of the flame retardant and colorant and industrial productivity.

[0066] <Molded body> After producing the polyamide resin composition, for example, pellets can be subjected to various molding methods to obtain a molded article. The molding method for the molded article may be appropriately selected depending on the application, and methods such as injection molding, extrusion molding, blow molding, compression molding, press molding, and calendar molding can be used. In particular, the polyamide resin composition of the present embodiment is suitable as an injection-molded article used in applications involving a surface mounting process, since it can withstand the reflow process and also gives a molded article having excellent flame retardancy.

[0067] <Application> The polyamide resin composition of the present embodiment has heat resistance sufficient to withstand a reflow process and gives molded articles with excellent flame retardancy, and is therefore useful as external connection terminals such as FPC connectors, BtoB connectors, card connectors, SMT connectors, coaxial connectors, and memory card connectors; SMT relays; SMT bobbins; sockets such as memory sockets and CPU sockets; switches such as command switches and SMT switches; sensors such as rotation sensors and acceleration sensors; and automotive parts such as IGBT module components for inverters, ECU housings, insulators, automotive connectors, engine mounts, intercoolers, and bearing retainers, and is particularly useful as SMT connectors, SMT relays, and IGBT module components for automobiles and electronic devices, and is particularly useful as SMT connectors. The molded article obtained from the polyamide resin composition of the present embodiment exhibits excellent flame retardancy, and can therefore be suitably used for SMT connectors or SMT relays. Examples of electronic devices equipped with a molded article obtained from the polyamide resin composition of the present embodiment include, but are not limited to, portable electronic devices such as smartphones and personal computers, and automobiles. [Example]

[0068] The present invention will be specifically explained below with reference to examples and comparative examples, but the present invention is not limited to these.

[0069] The melting point and glass transition temperature of the polyamide (A) used in the examples and comparative examples were measured according to the following methods.

[0070] (Melting point and glass transition temperature of polyamide (A)) The melting point of the polyamide (A) (PA9T described below) was determined by measuring the peak temperature of the melting peak that appeared when the temperature was raised from 30°C to 360°C at a rate of 10°C / min under a nitrogen atmosphere using a differential scanning calorimeter (DSC7020) manufactured by Hitachi High-Tech Science Corp. When there were multiple melting peaks, the peak temperature of the highest melting peak was taken as the melting point. The sample was then held at a temperature 30°C higher than the melting point for 10 minutes to completely melt it, then cooled to 40°C at a rate of 10°C / min and held at 40°C for 10 minutes. The temperature was then raised again at a rate of 10°C / min to a temperature 30°C higher than the melting point, and the midpoint at which the DSC curve changed in a stepwise manner was taken as the glass transition temperature.

[0071] [Examples 1 to 9 and Comparative Examples 1 to 5] Polyamide (A) and other components (antioxidant-1, antioxidant-2, mold release agent, and lubricant) in the amounts shown in Table 1 were fed from the most upstream hopper into a twin-screw extruder (manufactured by Plastics Engineering Research Institute) (screw diameter 32 mm, L / D=30, rotation speed 150 rpm, output rate 10 kg / h), and inorganic filler (B), phosphinate (C), phosphite (D), and colorant (E) in the amounts shown in Table 1 were further fed from a side feeder and melt-kneaded. The melt-kneaded polyamide resin composition was extruded into a strand, cooled, and cut to obtain pellets of the polyamide resin composition. In Table 1, the amounts of polyamide (A), inorganic filler (B), phosphinate (C), phosphite (D), and colorant (E) are all expressed in "parts by mass." The pellets obtained above were used to evaluate molded articles (flame retardancy, mechanical strength, sulfur content, color value) by the following methods. The results are shown in Table 2.

[0072] [Flame retardancy] Using an injection molding machine UH-1000 manufactured by Nissei Plastic Industrial Co., Ltd., pellets of the polyamide resin composition obtained in each Example or Comparative Example were injection-molded into plate-shaped test specimens (thicknesses of 0.4 mm, 0.75 mm, and 3.0 mm) measuring 12.5 mm wide and 125 mm long at a maximum cylinder temperature of 320°C, a mold temperature of 140°C, and an injection speed of 750 to 150 mm / s. The flame retardancy of these test specimens of each thickness was evaluated in accordance with the UL94 standard. <UL94 Standard Flame Retardancy Test> The upper end of the test piece is clamped to hold the test piece vertically, and a specified flame is applied to the lower end for 10 seconds and then released, measuring the burning time of the test piece (first time). Once the flame is extinguished, the flame is immediately applied to the lower end again for 10 seconds and then released, measuring the burning time of the test piece (second time). Repeat the same measurement for five pieces, obtaining a total of 10 data points: five for the first burning time and five for the second burning time. The total of the 10 data points is T, and the maximum value of the 10 data points is M. If T is less than 50 seconds, M is less than 10 seconds, the flame does not spread to the clamp, and the flaming molten material does not fall and ignite dry cotton set 12 inches below, the rating is "V-0." If T is less than 250 seconds, M is less than 30 seconds, and all other conditions are met as in V-0, the rating is "V-1." If T is less than 250 seconds, M is less than 30 seconds, the flame does not spread to the clamp, and the flaming molten material falls and ignites dry cotton set 12 inches below, the rating is "V-2."

[0073] [Mechanical strength] Using an injection molding machine UH-1000 manufactured by Nissei Plastic Industrial Co., Ltd., pellets of the polyamide resin compositions obtained in each example and comparative example were injection molded into dumbbell-shaped tensile test specimens (ISO 1A dumbbell) at a maximum cylinder temperature of 320°C, a mold temperature of 140°C, and an injection speed of 150 to 50 mm / s. The test pieces prepared by the above method were used to measure the tensile strength and tensile strain at break at 23° C. in accordance with ISO 527 using a tensile tester Instron 5969 (manufactured by Instron Japan Company Limited).

[0074] [Sulfur element content] The sulfur element content (ppm by mass) of the polyamide resin compositions obtained in each of the Examples and Comparative Examples was measured using the following apparatus and conditions. The polyamide resin composition pellets obtained in each of the Examples and Comparative Examples were spread over an aluminum cup to form a sample for measurement. Measurement equipment: Rigaku Corporation ZSX Primus μ scanning X-ray fluorescence analyzer X-ray tube: Rhodium 3.0kW ·Analysis diameter: φ30mm Atmosphere: Vacuum Sample spin: Measurement mode: FP method Filter:OUT Thin film for analysis window: 0.7 μm PET Slit: Standard -Analyzing crystal: Ge Detector: Proportional counter

[0075] [Color value (L * a * b * , ΔE) The color values ​​of the polyamide resin compositions obtained in the examples and comparative examples are shown in Table 1. * a * b * was measured using the following equipment and conditions. The polyamide resin compositions obtained in the examples and comparative examples were used as dumbbell-shaped tensile test pieces, ie, ISO 1A dumbbells, as samples for the measurements. Measuring device: RAL gGmbH colorimeter RAL COLORCATCH NANO Light source: CIE standard light source D65 Sensor: CCD camera (224 x 224 pixels) Measurement geometry: 45° / 0° Software: RAL iCOLOURS (version 3.7.2) Device used: Software used on iPhone 8 (iOS 13.3) The obtained L * a * b * From this, ΔE was calculated using the following formula (1). ΔE = (L * col -L * nat ) 2 +(a * col -a * nat ) 2 +(b * col -b * nat ) 2 〕 1 / 2 (1) In addition, in formula (1), L * col , a * ncol , and b * col The CIE1976(L) of the polyamide resin composition obtained in each example * a * b * ) L defined by the color system * , a * , and b * and L * nat , a * nat , and b * nat The polyamide resin composition containing no colorant (E) has the same composition as the polyamide resin composition described above, except that it does not contain the colorant (E). * a * b * ) L defined by the color system * , a * , and b * is.

[0076] The components shown in Table 1 are as follows: [Polyamide (A)] PA9T: "Genestar GC51010" (manufactured by Kuraray Co., Ltd., PA9T (a polyamide in which the dicarboxylic acid units are terephthalic acid units and the diamine units are 1,9-nonanediamine units and 2-methyl-1,8-octanediamine units (molar ratio 85 / 15)), melting point 305°C, glass transition temperature 125°C)

[0077] [Inorganic filler (B)] Glass fiber: "ECS03T-262H" (Nippon Electric Glass Co., Ltd., cross section: circular, 3 mm chopped strand, fiber diameter: 10.5 μm)

[0078] [Phosphinate (C)] Aluminum phosphinate: "Exolit OP 1230" (Clariant Chemicals, aluminum diethylphosphinate, number average particle size 25 μm) [Phosphite (D)] Aluminum phosphite: "APA-100" (manufactured by Taihei Chemical Industry Co., Ltd.)

[0079] [Colorant (E)] E-1: "Solvent Red 52" (red organic colorant, CAS number 81-39-0) E-2: "Solvent Red 179" (red organic colorant, CAS number 6829-22-7) E-3: "Iron (III) oxide" (red inorganic colorant, CAS number 1309-37-1) E-4: "Pigment Yellow 53" (yellow inorganic colorant, CAS number 8007-18-9) E-5: "Pigment Blue 15" (blue organic colorant, CAS number 147-14-8) E-6: "Pigment Green 50" (green inorganic colorant, CAS number 68186-85-6) E-7: "Pigment Brown 24" (brown inorganic colorant, CAS number 68186-90-3) E-8: "Solvent Yellow 98" (yellow organic colorant, CAS number 27870-92-4) E-9: "Solvent Orange 63" (orange organic colorant, CAS number 16924-75-0) E-10: "Ultramarine (Pigment Blue 29)" (blue inorganic colorant, CAS number 57455-37-5) E-11: "Zinc sulfide" (white inorganic colorant, CAS number 1314-98-3)

[0080] [Other ingredients] Antioxidant-1: "Irganox 1098" (BASF Japan Ltd.) Antioxidant-2: "Irgafos168" (BASF Japan Ltd.) Release agent: High density polyethylene "HI WAX NP055" (Mitsui Chemicals, Inc.) Lubricant: Calcium stearate "Calcium Stearate S" (NOF Corporation) Core material: Talc "Micron White #5000S" (Hayashi Kasei Co., Ltd.)

[0081] In Table 1, "(C)+(D)" is the total content (mass %) of the phosphinate (C) and the phosphite (D) relative to 100 mass % of the polyamide resin composition. In Table 1, "(C) / (D)" refers to the mass ratio of the phosphinate (C) to the phosphite (D).

[0082] [Table 1]

[0083] [Table 2]

[0084] As shown in Table 1, a comparison between the Examples and Comparative Examples reveals that the molded articles of the colored polyamide resin composition of this embodiment have excellent flame retardancy. Furthermore, since the polyamide resin composition of this embodiment uses polyamide (A) having a melting point of 280°C or higher, it can be said that it has heat resistance sufficient to withstand the reflow process. [Industrial Applicability]

[0085] The colored polyamide resin composition of the present embodiment has heat resistance sufficient to withstand a reflow process and gives molded articles having excellent flame retardancy, and is therefore useful as external connection terminals such as FPC connectors, BtoB connectors, card connectors, SMT connectors, coaxial connectors, and memory card connectors; SMT relays; SMT bobbins; sockets such as memory sockets and CPU sockets; switches such as command switches and SMT switches; sensors such as rotation sensors and acceleration sensors; and automotive parts such as IGBT module components for inverters, ECU housings, insulators, automotive connectors, engine mounts, intercoolers, and bearing retainers.

Claims

1. A polyamide resin composition comprising, relative to 100 parts by mass of polyamide (A) having a melting point of 280°C or higher, 45 to 120 parts by mass of inorganic filler (B), 25 to 40 parts by mass of at least one phosphinate (C) represented by the following formula (I) or (II), 2 to 15 parts by mass of phosphite (D), and a colorant (E), wherein the colorant (E) does not contain carbon black, has a sulfur element content of less than 220 ppm by mass, and has a ΔE represented by the following formula (1) of greater than 1. 【Chemical Formula 1】 【Chemistry 2】 [In formula (I) and formula (II), R １ , R ２ , R ４ and R ５ R each independently represents a linear or branched alkyl group having 1 to 16 carbon atoms. １ and R ２ and R ４ and R ５ may be bonded to each other to form a ring. ３ represents a linear or branched alkylene group having 1 to 10 carbon atoms, an arylene group having 6 to 10 carbon atoms, an alkylarylene group having 7 to 20 carbon atoms, a cycloalkylene group having 3 to 10 carbon atoms, an aralkylene group having 7 to 10 carbon atoms, or an arylalkylene group having 7 to 20 carbon atoms. M represents calcium, magnesium, aluminum, or zinc. m is an integer of 1 to 4. n is an integer of 1 to 4. x is an integer of 1 to 4. In formula (II), m, x, and n satisfy the relationship mx=2n.] ΔE=〔(L ＊ ｃｏｌ -L ＊ ｎａｔ ) ２ +(a ＊ ｃｏｌ -a ＊ ｎａｔ ) ２ +(b ＊ ｃｏｌ -b ＊ ｎａｔ ) ２ 〕 １／２ (1) [In formula (1), ΔE is CIE1976 (L ＊ a ＊ b ＊ ) is the color difference defined by the color system, and L ＊ ｃｏｌ , a ＊ ｃｏｌ , and b ＊ ｃｏｌ is the CIE1976 (L ＊ a ＊ b ＊ ) L defined by the color system ＊ , a ＊ , and b ＊ and L ＊ ｎａｔ , a ＊ ｎａｔ , and b ＊ ｎａｔ is a CIE1976 (L) of a colorant-free polyamide resin composition having the same composition as the polyamide resin composition except that it does not contain the colorant (E). ＊ a ＊ b ＊ ) L defined by the color system ＊ , a ＊ , and b ＊ It is.]

2. 2. The polyamide resin composition according to claim 1, wherein the colorant (E) contains an organic colorant, and the organic colorant is at least one selected from the group consisting of anthraquinone dyes, perinone dyes, anthrapyridone dyes, and phthalocyanine dyes.

3. 2. The polyamide resin composition according to claim 1, wherein the colorant (E) contains an organic colorant, and the organic colorant is a phthalocyanine pigment.

4. 2. The polyamide resin composition according to claim 1, wherein the colorant (E) contains an inorganic colorant, and the inorganic colorant is at least one selected from the group consisting of metal oxides and composite metal oxides.

5. A polyamide resin composition described in any of claims 1 to 3, wherein the colorant (E) contains an organic colorant, and the content of the organic colorant is 0.001 to 5.0 mass% relative to 100 mass% of the polyamide resin composition.

6. A polyamide resin composition according to claim 1 or 4, wherein the colorant (E) contains an inorganic colorant, and the content of the inorganic colorant is 0.01 to 5.0 mass% relative to 100 mass% of the polyamide resin composition.

7. 7. The polyamide resin composition according to claim 1, wherein the phosphite (D) is aluminum phosphite or aluminum hydrogen phosphite, the total amount of the phosphinate (C) and the phosphite (D) is 16 to 25 mass% based on the polyamide resin composition, and a mass ratio (C) / (D) of the phosphinate (C) to the phosphite (D) is 70 / 30 to 94 / 6.

8. The polyamide resin composition according to any one of claims 1 to 7, wherein the polyamide (A) contains diamine units, and 50 to 100 mol% of the diamine units are aliphatic diamine units having 4 to 18 carbon atoms.

9. The polyamide resin composition according to any one of claims 1 to 8, wherein the polyamide (A) comprises a dicarboxylic acid unit and a diamine unit, the main component of the dicarboxylic acid unit is a unit derived from terephthalic acid, and the main component of the diamine unit is at least one selected from aliphatic diamines having 4 to 12 carbon atoms.

10. The polyamide resin composition according to any one of claims 1 to 9, wherein the inorganic filler (B) is at least one selected from glass fibers having a circular cross section and glass fibers having a non-circular cross section.

11. The polyamide resin composition according to any one of claims 1 to 10, wherein the inorganic filler (B) is a glass fiber having a circular cross section and a glass fiber having a non-circular cross section, and the circumferential length of the cross section of the glass fiber having a circular cross section is 1.05 to 1.8 times the circumferential length of the glass fiber having a circular cross section and having the same cross-sectional area as the non-circular cross section.

12. A method for producing the polyamide resin composition according to any one of claims 1 to 11.

13. A molded article of the polyamide resin composition according to any one of claims 1 to 11.

14. The molded article according to claim 13, which is an injection molded article used in an application having a surface mounting process.

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