Polyamide resin composition and molded article

Abstract

This polyamide resin composition comprises a polyamide resin (A), a phosphorus compound (B), and glass fibers (C) containing a surface treatment agent or a sizing agent. The phosphorus element content of the polyamide resin composition is 500 to 10,000 ppm by mass with respect to the polyamide resin composition.

Description

Polyamide resin composition and molded article

[0001] The present invention relates to a polyamide resin composition and a molded article.

[0002] BACKGROUND ART Polyamide resin compositions have been widely used as materials for various parts for clothing, industrial materials, automobiles, electrical and electronic products, industrial applications, etc. because of their excellent moldability, mechanical properties, and chemical resistance.

[0003] Various additives are added to polyamide resin compositions used for these applications to achieve properties suited to each application. For example, it is known that a reinforcing material such as glass fiber is blended into a polyamide resin composition to increase its mechanical strength.

[0004] The glass fibers may be treated with a sizing agent or a surface treatment agent to improve dispersibility in polyamide resin, etc. Known examples of sizing agents and surface treatment agents for glass fibers include epoxy compounds, amine compounds, urethane compounds, and carboxylic acid compounds.

[0005] Furthermore, a flame retardant may be added to impart flame retardancy. For example, Patent Document 1 discloses a resin composition containing a specific semi-aromatic polyamide, polyphenylene ether, a phosphazene compound and phosphinates as flame retardants, and glass fiber. This document states that excellent flame retardancy can be obtained by using a phosphazene compound and phosphinates in combination as flame retardants. In the examples and comparative examples of this document, the total amount of the phosphazene compound and phosphinates in the resin composition is approximately 8 to 15 mass%, and the content of phosphorus derived from these compounds is calculated to be 1.37 mass% at the lowest content.

[0006] Furthermore, Patent Document 2 discloses a flame-retardant polyamide resin composition comprising 30 to 80 wt% polyamide resin, 1 to 30 wt% of a melamine-phosphoric acid adduct, 1 to 30 wt% of a specific phosphinate, 0.01 to 5 wt% of a monoester derivative of a polyalkylene polyhydric alcohol and a higher fatty acid, and 5 to 40 wt% of an inorganic filler. This document claims that the combined use of 1 to 30 wt% of a melamine-phosphoric acid adduct and a specific phosphinate can enhance not only flame retardancy but also tracking resistance. In the examples and comparative examples of this document, the phosphorus content derived from the melamine polyphosphate and the phosphinate in the flame-retardant polyamide resin composition is calculated to be 1.96 to 3.7 wt%.

[0007] International Publication No. 2008 / 081878 Japanese Patent Application Laid-Open No. 2004-292531

[0008]

[0003] Meanwhile, for example, electrical and electronic components used under high voltage environments are required to have high tracking resistance. According to the studies of the present inventors, the tracking resistance can be highly improved by adding a large amount of a phosphorus compound to a polyamide resin composition. However, a new problem has been discovered in that adding a large amount of a phosphorus compound to a polyamide resin composition containing glass fibers treated with a surface treatment agent or a sizing agent reduces the mechanical strength (particularly flexural strength) of the polyamide resin composition.

[0009] In view of these circumstances, an object of the present invention is to provide a polyamide resin composition that has high tracking resistance while maintaining good mechanical strength, and a polyamide molded article containing the polyamide resin composition.

[0010] The present invention relates to the following polyamide resin composition and molded article.

[0011] [1] A polyamide resin composition comprising a polyamide resin (A) having a melting point of 280°C or higher as measured by differential scanning calorimetry (DSC), a phosphorus compound (B), and glass fibers (C) containing a surface treatment agent or a sizing agent, wherein the phosphorus content of the polyamide resin composition is 500 ppm by mass or more and 10,000 ppm by mass or less, based on the polyamide resin composition. [2] The polyamide resin composition according to [1], wherein the surface treatment agent or sizing agent has an acidic group. [3] The polyamide resin composition according to [2], wherein the acidic group is a carboxy group, an acid anhydride group, or a carboxylic acid ester group. [4] The polyamide resin composition according to [2] or [3], wherein the surface treatment agent or sizing agent comprises a compound having an acidic group and a urethane resin. [5] The polyamide resin composition according to any one of [1] to [4], wherein the phosphorus compound (B) comprises a phosphinate compound. [6] The polyamide resin composition according to [5], wherein the phosphinate compound is at least one selected from the group consisting of compounds represented by formula (I) or formula (II) or condensates thereof: [In the formula, R １ and R ２ are each a C1 to C6 alkyl group or an aryl group, R ３is a C1 to C10 alkylene group, a C6 to C10 arylene group, a C6 to C10 alkylarylene group, or a C6 to C10 arylalkylene group, M is one selected from the group consisting of Mg, Ca, Al, Sb, Sn, Ge, Ti, Zn, Fe, Zr, Ce, Bi, Sr, Mn, Li, Na, K, and a protonated nitrogen base, m is an integer of 1 to 4, n is an integer of 1 to 4, and x is an integer of 1 to 4.] [7] The polyamide resin composition according to any one of [1] to [6], wherein the phosphorus compound (B) includes aluminum diethylphosphinate. [8] The polyamide resin composition according to any one of [1] to [7], wherein the polyamide resin (A) has a heat of fusion (ΔH) of 10 J / g or more as measured by differential scanning calorimetry (DSC). [9] The polyamide resin composition according to any one of [1] to [8], wherein the polyamide resin (A) comprises a component unit (Aa) derived from a dicarboxylic acid and a component unit (Ab) derived from a diamine, and the component unit (Aa) derived from the dicarboxylic acid comprises a component unit derived from an aromatic dicarboxylic acid.

[10] The polyamide resin composition according to any one of [1] to [9], wherein the polyamide resin (A) comprises a component unit (Aa) derived from a dicarboxylic acid and a component unit (Ab) derived from a diamine, and the component unit (Aa) derived from the dicarboxylic acid comprises a component unit derived from terephthalic acid and a component unit derived from isophthalic acid.

[11] The polyamide resin composition according to any one of [1] to

[10] , wherein the content of the phosphorus compound (B) is 0.5% by mass or more and less than 5% by mass, relative to the polyamide resin composition.

[12] The polyamide resin composition according to any one of [1] to

[11] , wherein the content of the glass fiber (C) is 25% by mass or more and 60% by mass or less, relative to the polyamide resin composition.

[13] A molded article comprising the polyamide resin composition according to any one of [1] to

[12] .

[0012] According to the present invention, it is possible to provide a polyamide resin composition having high tracking resistance while maintaining good mechanical strength, and a polyamide molded article containing the polyamide resin composition.

[0013] FIG. 1 is a graph plotting the results obtained in the examples and comparative examples.

[0014] 1. Polyamide Resin Composition The polyamide resin composition contains a polyamide resin (A), a phosphorus compound (B), and glass fibers (C) containing a surface treatment agent or a sizing agent.

[0015] 1-1. Polyamide Resin (A) The polyamide resin (A) contains a component unit (Aa) derived from a dicarboxylic acid and a component unit (Ab) derived from a diamine.

[0016] [Dicarboxylic acid-derived component units (Aa)] The dicarboxylic acid-derived component units (Aa) preferably include component units derived from aromatic dicarboxylic acids or alicyclic dicarboxylic acids, and more preferably include component units derived from aromatic dicarboxylic acids. When the polyamide resin (A) includes component units derived from aromatic dicarboxylic acids or alicyclic dicarboxylic acids as the dicarboxylic acid-derived component units (Aa), the melting point (Tm) and crystallinity can be sufficiently increased, and when the polyamide resin (A) includes component units derived from aromatic dicarboxylic acids, the melting point (Tm) and crystallinity can be even more sufficiently increased.

[0017] Examples of aromatic dicarboxylic acids include terephthalic acid, isophthalic acid, naphthalenedicarboxylic acid and their esters. Examples of alicyclic dicarboxylic acids include cyclohexanedicarboxylic acid and its esters.

[0018] In this embodiment, the dicarboxylic acid-derived component units (Aa) preferably include component units (Aa1) derived from terephthalic acid, naphthalenedicarboxylic acid, or cyclohexanedicarboxylic acid. These component units (Aa1), unlike, for example, isophthalic acid, can enhance the crystallinity of the polyamide. From the viewpoint of ensuring the crystallinity of the polyamide resin, the content of these component units (Aa1) is preferably greater than 20 mol% and less than 100 mol% relative to the total number of moles of the dicarboxylic acid-derived component units (Aa). From the viewpoint of further enhancing the crystallinity of the polyamide resin (A), the content of these component units (Aa1) is preferably greater than 45 mol% and less than 100 mol%, more preferably greater than 50 mol% and less than 99 mol%, and even more preferably greater than 60 mol% and less than 80 mol% relative to the total number of moles of the dicarboxylic acid-derived component units (Aa). In particular, from the viewpoint of obtaining a polyamide resin with high crystallinity and high heat resistance, the component units (Aa1) are more preferably component units derived from terephthalic acid.

[0019] The dicarboxylic acid-derived component unit (Aa) may further include a component unit (Aa2) derived from an aromatic dicarboxylic acid other than the component unit (Aa1) or a component unit (Aa3) derived from an aliphatic dicarboxylic acid having from 4 to 18 carbon atoms, as long as the effects of the present invention are not impaired.

[0020] Examples of the component unit (Aa2) derived from an aromatic dicarboxylic acid other than terephthalic acid include component units derived from isophthalic acid and 2-methylterephthalic acid, preferably a component unit derived from isophthalic acid. When the polyamide resin (A) contains the component unit (Aa2), the content of the component unit (Aa2) is preferably 1 mol% to 50 mol%, more preferably 10 mol% to 40 mol%, even more preferably 15 mol% to 40 mol%, and particularly preferably 20 mol% to 40 mol%, based on the total number of moles of the component units (Aa) derived from dicarboxylic acids, from the viewpoint of ensuring the crystallinity of the polyamide resin.

[0021] The component unit (Aa3) derived from an aliphatic dicarboxylic acid is a component unit derived from an aliphatic dicarboxylic acid having an alkylene group containing from 4 to 18 carbon atoms, and is preferably a component unit derived from an aliphatic dicarboxylic acid having an alkylene group containing from 6 to 12 carbon atoms. Examples of aliphatic dicarboxylic acids include malonic acid, dimethylmalonic acid, succinic acid, glutaric acid, adipic acid, 2-methyladipic acid, trimethyladipic acid, pimelic acid, 2,2-dimethylglutaric acid, 3,3-diethylsuccinic acid, azelaic acid, sebacic acid, and suberic acid component units, and preferably component units derived from adipic acid and sebacic acid. Of these, adipic acid and sebacic acid are preferred. When the polyamide resin (A) contains the component units (Aa3), the content of these component units (Aa3) is, from the viewpoint of ensuring the crystallinity of the polyamide resin, preferably from 0 mol % to 40 mol %, more preferably from 0 mol % to 20 mol %, even more preferably from 1 mol % to 10 mol %, and particularly preferably from 1 mol % to 5 mol %, relative to the total number of moles of the component units (Aa) derived from dicarboxylic acid.

[0022] Of the component units (Aa2) and (Aa3), from the viewpoint of being able to appropriately lower the crystallinity while maintaining the melting point of the polyamide resin (A), it is preferable that the component unit (Aa) derived from a dicarboxylic acid further contains a component unit (Aa2), and it is more preferable that the component unit (Aa2) further contains a component unit derived from isophthalic acid.

[0023] The polyamide resin (A) may further contain a small amount of a tribasic or higher polycarboxylic acid unit such as trimellitic acid or pyromellitic acid in addition to the above-mentioned unit (Aa1), unit (Aa2), and unit (Aa3). The content of such a polycarboxylic acid unit may be 0 mol % or more and 5 mol % or less based on the total number of moles of the unit (Aa) derived from a dicarboxylic acid.

[0024] [Diamine-Derived Component Unit (Ab)] The diamine-derived component unit (Ab) preferably includes a component unit (Ab1) derived from a linear alkylenediamine having 4 to 18 carbon atoms, and may further include a component unit (Ab2) derived from an alkylenediamine having 4 to 18 carbon atoms and having a side chain alkyl group, or a component unit (Ab3) derived from an alicyclic diamine having 4 to 20 carbon atoms.

[0025] With respect to the diamine-derived component units (Ab), when the total number of moles of diamine-derived component units contained in the polyamide resin (A) is taken as 100 mol%, the amount of component units (Ab1) derived from linear alkylenediamines having 4 to 18 carbon atoms is preferably 20 mol% to 100 mol%, more preferably 20 mol% to 80 mol%. When the content of the component units is 20 mol% or more, the crystallization rate is not excessively slowed, making it easy to appropriately increase the crystallinity and mechanical strength of the polyamide resin (A). When the content of the component units is 100 mol% or less, preferably 80 mol% or less, the crystallization rate of the polyamide resin (A) is not excessively high, making it difficult to impair fluidity during molding. From the same perspective, the content of component units derived from linear aliphatic diamines is more preferably 30 mol% to 60 mol% of the total.

[0026] Furthermore, the diamine-derived component units (Ab) may contain component units (Ab2) derived from an alkylenediamine having 4 to 18 carbon atoms and a side chain alkyl group or component units (Ab3) derived from an alicyclic diamine having 4 to 20 carbon atoms. In this case, when the total number of moles of diamine-derived component units contained in the polyamide resin (A) is taken as 100 mol%, the amount of component units (Ab2) derived from an alkylenediamine having 4 to 18 carbon atoms and a side chain alkyl group or component units (Ab3) derived from an alicyclic diamine having 4 to 20 carbon atoms is preferably 20 mol% or more and 80 mol% or less. When the content of these component units is 20 mol% or more, the crystallization rate of the polyamide resin (A) tends to be appropriately slowed, thereby improving fluidity during molding. When the content of these component units is 80 mol% or less, the crystallinity and mechanical strength of the polyamide resin (A) are less likely to be impaired. From the same viewpoint, the content of the component units derived from the branched aliphatic diamine is more preferably 40 mol % or more and 70 mol % or less of the above total.

[0027] Examples of the component unit (Ab1) derived from a linear alkylenediamine having 4 to 18 carbon atoms include component units derived from 1,4-diaminobutane, 1,6-diaminohexane, 1,7-diaminoheptane, 1,8-diaminooctane, 1,9-diaminononane, 1,10-diaminodecane, 1,11-diaminoundecane, and 1,12-diaminododecane. Of these, component units derived from 1,6-diaminohexane, 1,8-diaminooctane, 1,10-diaminodecane, and 1,12-diaminododecane are preferred, with 1,6-diaminohexane component units being more preferred. Multiple types of these component units may be contained in the polyamide resin (A).

[0028] Examples of the component unit (Ab2) derived from an alkylenediamine having 4 to 18 carbon atoms and a side chain alkyl group include 1-butyl-1,2-diamino-ethane, 1,1-dimethyl-1,4-diamino-butane, 1-ethyl-1,4-diamino-butane, 1,2-dimethyl-1,4-diamino-butane, 1,3-dimethyl-1,4-diamino-butane, 1,4-dimethyl-1,4-diamino-butane, 2,3-dimethyl-1,4-diamino-butane, 2-methyl-1,5-diaminopentane, 2, 5-dimethyl-1,6-diamino-hexane, 2,4-dimethyl-1,6-diamino-hexane, 3,3-dimethyl-1,6-diamino-hexane, 2,2-dimethyl-1,6-diamino-hexane, 2,2,4-trimethyl-1,6-diamino-hexane, 2,4,4-trimethyl-1,6-diamino-hexane, 2,4-diethyl-1,6-diamino-hexane, 2,3-dimethyl-1,7-diamino-heptane, 2,4-dimethyl-1,7-diamino-heptane, 2,5-dimethyl 1,7-diamino-heptane, 2,2-dimethyl-1,7-diamino-heptane, 2-methyl-4-ethyl-1,7-diamino-heptane, 2-ethyl-4-methyl-1,7-diamino-heptane, 2,2,5,5-tetramethyl-1,7-diamino-heptane, 3-isopropyl-1,7-diamino-heptane, 3-isooctyl-1,7-diamino-heptane, 1,3-dimethyl-1,8-diamino-octane, 1,4-dimethyl-1,8-diamino-octane, 2,4-dimethyl- Examples of component units include those derived from 1,8-trimethyl-1,8-diamino-octane, 3,4-dimethyl-1,8-diamino-octane, 4,5-dimethyl-1,8-diamino-octane, 2,2-dimethyl-1,8-diamino-octane, 3,3-dimethyl-1,8-diamino-octane, 4,4-dimethyl-1,8-diamino-octane, 3,3,5-trimethyl-1,8-diamino-octane, 2,4-diethyl-1,8-diamino-octane, and 5-methyl-1,9-diamino-nonane. Of these, component units derived from side-chain alkyldiamines having one or two side-chain alkyl groups each having 1 to 2 carbon atoms and having a main chain of 4 to 10 carbon atoms are preferred, with 2-methyl-1,5-diaminopentane being more preferred.The polyamide resin (A) may contain a plurality of types of these component units.

[0029] Examples of the component unit (Ab3) derived from an alicyclic diamine having 4 to 20 carbon atoms include 1,3-diaminocyclohexane, 1,4-diaminocyclohexane, 1,3-bis(aminomethyl)cyclohexane, 1,4-bis(aminomethyl)cyclohexane, 2,5-bisaminomethylnorbornane, 2,6-bisaminomethylnorbornane, isophoronediamine, piperazine, 2,5-dimethylpiperazine, bis(4-aminocyclohexyl)methane, 1,3-bis(aminocyclohexyl)methane, bis(4-aminocyclohexyl)propane, and 4,4'-diamino-3,3'-dimethyldicyclohexylpropane. The constituent units include those derived from 4,4'-diamino-3,3'-dimethyldicyclohexylmethane, 4,4'-diamino-3,3'-dimethyl-5,5'-dimethyldicyclohexylmethane, 4,4'-diamino-3,3'-dimethyl-5,5'-dimethyldicyclohexylpropane, α,α'-bis(4-aminocyclohexyl)-p-diisopropylbenzene, α,α'-bis(4-aminocyclohexyl)-m-diisopropylbenzene, α,α'-bis(4-aminocyclohexyl)-1,4-cyclohexane, and α,α'-bis(4-aminocyclohexyl)-1,3-cyclohexane. Among these, component units derived from 1,3-diaminocyclohexane, 1,4-diaminocyclohexane, 1,3-bis(aminomethyl)cyclohexane, 1,4-bis(aminomethyl)cyclohexane, 2,5-bisaminomethylnorbornane, 2,6-bisaminomethylnorbornane, bis(4-aminocyclohexyl)methane, and 4,4'-diamino-3,3'-dimethyldicyclohexylmethane are preferred, and component units derived from 1,3-diaminocyclohexane, 1,4-diaminocyclohexane, 1,3-bis(aminomethyl)cyclohexane, 2,5-bisaminomethylnorbornane, 2,6-bisaminomethylnorbornane, and bis(4-aminocyclohexyl)methane are more preferred.

[0030] In this specification, unless otherwise specified, the number of carbon atoms in a component unit derived from an alkylenediamine having a side chain alkyl group is the sum of the number of carbon atoms in the main chain alkylene group and the number of carbon atoms in the side chain alkyl group.

[0031] In addition to the aforementioned component units (Ab1), (Ab2), and (Ab3), the polyamide resin (A) may further contain a small amount of component units derived from other diamines, such as component units derived from metaxylylenediamine. The content of such component units derived from other diamines may be 50 mol % or less, and preferably 40 mol % or less, based on the total amount of the diamine-derived component units (Ab).

[0032] In order to improve the thermal stability during compounding or molding and to further increase the mechanical strength, at least some of the molecular terminal groups of the polyamide resin (A) may be capped with a terminal capping agent. For example, when the molecular terminal is a carboxy group, the terminal capping agent is preferably a monoamine, and when the molecular terminal is an amino group, the terminal capping agent is preferably a monocarboxylic acid.

[0033] Examples of monoamines include aliphatic monoamines such as methylamine, ethylamine, propylamine, and butylamine, alicyclic monoamines such as cyclohexylamine and dicyclohexylamine, and aromatic monoamines such as aniline and toluidine. Examples of monocarboxylic acids include aliphatic monocarboxylic acids having from 2 to 30 carbon atoms such as acetic acid, propionic acid, butyric acid, valeric acid, caproic acid, caprylic acid, lauric acid, tridecylic acid, myristic acid, palmitic acid, stearic acid, oleic acid, and linoleic acid, aromatic monocarboxylic acids such as benzoic acid, toluic acid, naphthalenecarboxylic acid, methylnaphthalenecarboxylic acid, and phenylacetic acid, and alicyclic monocarboxylic acids such as cyclohexanecarboxylic acid. The aromatic monocarboxylic acid and the alicyclic monocarboxylic acid may have a substituent on the cyclic structure portion.

[0034] The dicarboxylic acid-derived component unit (Aa) of the polyamide resin (A) may include a biomass-derived dicarboxylic acid-derived component unit, and the diamine-derived component unit (Ab) may include a biomass-derived diamine-derived component unit. The polyamide resin (A) may also be a biomass-derived polyamide resin (A) obtained by polymerizing a group of raw materials including a biomass-derived raw material.

[0035] [Physical Properties] The melting point (Tm) of the polyamide resin (A) measured by a differential scanning calorimeter (DSC) (hereinafter sometimes simply referred to as the melting point (Tm)) is preferably 280°C or higher and 340°C or lower. When the melting point (Tm) of the polyamide resin (A) is 280°C or higher, the mechanical strength and heat resistance of the resin composition and molded article in the high temperature range are less likely to be impaired, and when it is 340°C or lower, there is no need to excessively increase the molding temperature, so the molding processability of the resin composition is likely to be good. From the above viewpoints, the melting point (Tm) of the polyamide resin is more preferably 290°C or higher and 340°C or lower, and even more preferably 300°C or higher and 340°C or lower.

[0036] The glass transition temperature (Tg) of the polyamide resin (A) is preferably 80°C or higher and 150°C or lower.

[0037] The heat of fusion (ΔH) of the polyamide resin (A) is preferably 20 J / g or more. When the heat of fusion (ΔH) of the polyamide resin (A) is 20 J / g or more, it has crystallinity, which makes it easy to improve the heat resistance of the resin member. The upper limit of the heat of fusion (ΔH) of the polyamide resin (A) is not particularly limited, but can be 130 J / g from the viewpoint of not impairing moldability. The heat of fusion (ΔH) of the polyamide resin (A) is preferably 30 J / g or more and 130 J / g or less, more preferably 30 J / g or more and 100 J / g or less.

[0038] The heat of fusion (ΔH), melting point (Tm) and glass transition temperature (Tg) of the polyamide resin (A) can be measured using a differential scanning calorimeter (DSC220C, manufactured by Seiko Instruments Inc.).

[0039] Specifically, approximately 5 mg of polyamide resin (A) is sealed in a measuring aluminum pan and heated from room temperature to 350°C at 10°C / min. To completely melt the resin, the temperature is held at 350°C for 3 minutes, and then cooled to 30°C at 10°C / min. After leaving the resin at 30°C for 5 minutes, a second heating is performed to 350°C at 10°C / min. The temperature (°C) of the endothermic peak during this second heating is taken as the melting point (Tm) of polyamide resin (A), and the inflection point corresponding to the glass transition is taken as the glass transition temperature (Tg). The heat of fusion (ΔH) is determined from the area of ​​the endothermic peak during the second heating process in accordance with JIS K7122.

[0040] The melting point (Tm), glass transition temperature (Tg), and heat of fusion (ΔH) of the polyamide resin (A) can be adjusted by adjusting the composition of the dicarboxylic acid-derived component unit (Aa) and the diamine-derived component unit (Ab). For example, increasing the content of the terephthalic acid-derived component unit (Aa1) or decreasing the content of the aromatic dicarboxylic acid other than terephthalic acid, such as isophthalic acid, (Aa2) tends to increase the melting point (Tm), glass transition temperature (Tg), and heat of fusion (ΔH) of the polyamide resin (A).

[0041] The intrinsic viscosity [η] of the polyamide resin (A) measured in 96.5% sulfuric acid at 25°C is preferably 0.6 dl / g or more and 1.5 dl / g or less. When the intrinsic viscosity [η] of the polyamide resin (A) is 0.6 dl / g or more, the mechanical strength (toughness, etc.) of the molded product is easily increased, and when it is 1.5 dl / g or less, the fluidity of the polyamide resin composition during molding is less likely to be impaired. From the same viewpoint, the intrinsic viscosity [η] of the polyamide resin (A) is more preferably 0.8 dl / g or more and 1.2 dl / g or less. The intrinsic viscosity [η] can be adjusted by the amount of terminal blocking of the polyamide resin (A), etc.

[0042] The intrinsic viscosity of a polyamide resin can be measured in accordance with JIS K6810-1977. Specifically, 0.5 g of polyamide resin is dissolved in 50 ml of 96.5% sulfuric acid solution to prepare a sample solution. The number of seconds it takes for this sample solution to flow down is measured using an Ubbelohde viscometer under conditions of 25±0.05°C, and the obtained value can be applied to the following formula to calculate the intrinsic viscosity: [η]=ηSP / [C(1+0.205ηSP)]

[0043] In the above formula, each algebra or variable represents the following: [η]: intrinsic viscosity (dl / g) ηSP: specific viscosity C: sample concentration (g / dl)

[0044] ηSP is calculated by the following formula: ηSP = (t - t0) / t0, where t: number of seconds (seconds) for the sample solution to flow down, and t0: number of seconds (seconds) for the blank sulfuric acid to flow down.

[0045] The amount of terminal amino groups in the polyamide resin (A) is preferably 10 mmol / kg or more and 150 mmol / kg or less, more preferably 15 mmol / kg or more and 130 mmol / kg or less, and even more preferably 20 mmol / kg or more and 100 mmol / kg or less. When the amount of terminal amino groups in the polyamide resin (A) is 10 mmol / kg or more, it is likely to chemically interact with the glass fiber (C) treated with a surface treatment agent or a sizing agent, making it easier to disperse the glass fiber (C). Furthermore, in the presence of the glass fiber (C) treated with a surface treatment agent or a sizing agent, a decrease in bending strength is likely to occur when a large amount of the phosphorus compound (B) is added. Therefore, the effect of suppressing the decrease in bending strength by limiting the amount of the phosphorus compound (B) to a certain level or less is more significant. When the amount of terminal amino groups in the polyamide resin (A) is 150 mmol / kg or less, excessive chemical interaction between the polyamide resin (A) and the glass fiber (C) is unlikely to occur, and the flowability of the polyamide resin composition can be sufficiently ensured.

[0046] The amount of terminal carboxylic acid groups in the polyamide resin (A) is preferably 60 mmol / kg or more and 220 mmol / kg or less, more preferably 80 mmol / kg or more and 200 mmol / kg or less, and even more preferably 100 mmol / kg or more and 180 mmol / kg or less.

[0047] The amount of terminal amino groups and the amount of terminal carboxylic acid groups can be measured by NMR. For example, polyamide resin (A) is dissolved in deuterated hexafluoroisopropanol (HFIP) to prepare a sample for NMR measurement, and NMR measurement is performed to obtain an NMR spectrum. From the ratio of the peak area of ​​the methylene group hydrogen adjacent to the terminal carboxylic acid structure to the peak area of ​​the methylene group hydrogen adjacent to the amide structure in the obtained spectrum, the amount of terminal carboxylic acid structures (μeq / g) can be obtained as a numerical value per part by mass of polyamide resin (A). Furthermore, from the peak area derived from the terminal amine structure and the peak area of ​​the methylene group hydrogen of the carboxylic acid component constituting the amide structure, the amount of terminal amine structures (μeq / g) can be obtained as a numerical value per part by mass of polyamide resin (A). The obtained numerical value can be converted to mmol / kg.

[0048] [Production Method] The polyamide resin (A) can be produced, for example, by polycondensing the above-mentioned dicarboxylic acid and the above-mentioned diamine in a homogeneous solution. Specifically, the polyamide resin (A) can be produced by heating the dicarboxylic acid and the diamine in the presence of a catalyst to obtain a low-order condensate, as described in WO 03 / 085029, and then applying shear stress to a melt of the low-order condensate to polycondense it.

[0049] The aforementioned terminal blocking agent may be added to the reaction system from the viewpoint of adjusting the intrinsic viscosity of the polyamide resin (A). The intrinsic viscosity [η] (or molecular weight) of the polyamide resin can be adjusted by adjusting the amount of the terminal blocking agent added.

[0050] The end-capping agent is added to the reaction system of the dicarboxylic acid and the diamine, preferably in an amount of 0.07 mol or less, more preferably 0.05 mol or less, per mol of the total amount of the dicarboxylic acid.

[0051] The content of polyamide resin (A) in the polyamide resin composition is preferably 25% by mass or more and 80% by mass or less, more preferably 35% by mass or more and 70% by mass or less, and even more preferably 45% by mass or more and 65% by mass or less, relative to the polyamide resin composition. The higher the content of polyamide resin (A), the higher the mechanical strength of the resulting molded article. On the other hand, from the viewpoint of further improving the properties by adding other components, the upper limit of the content of polyamide resin (A) can be set to the above range.

[0052] 1-2. Phosphorus Compound (B) Phosphorus compound (B) can be added to improve the tracking resistance of the polyamide resin composition. The phosphorus compound (B) is not particularly limited as long as it contains a phosphorus element in the molecule, and may be a phosphorus compound used as a flame retardant. The phosphorus compound (B) is preferably added by mixing with the polyamide resin (A), glass fiber (C), and, if necessary, other components after synthesizing the polyamide resin (A) by the above-described polycondensation reaction or the like. The phosphorus compound (B) preferably includes a compound having a -P(=O)- structure, and more preferably includes a compound having a -P(=O)-O- structure. Furthermore, the phosphorus compound (B) preferably includes a phosphinate compound, and more preferably includes a metal phosphinate compound. The mechanism by which the phosphorus compound (B) improves tracking resistance is not clear, but is speculated as follows.

[0053] Tracking fracture is thought to occur when, when a discharge occurs near the surface of a molded article of a polyamide resin composition, the heat generated by the discharge heats and carbonizes the polyamide resin (A), thereby reducing the electrical resistance of the surface of the molded article. On the other hand, if the polyamide resin composition contains a phosphorus compound (B), a hydrolysis reaction of the polyamide resin (A) by the phosphorus compound (B) may occur when a discharge occurs. Because the hydrolysis reaction is an endothermic reaction, heating of the polyamide resin (A) by the heat generated by the discharge is suppressed. This is thought to result in suppression of tracking fracture. Furthermore, when the phosphorus compound (B) contains a compound having a -P(=O)-O- structure, the phosphorus compound (B) is hydrolyzed to a compound having a highly acidic -P(=O)-OH structure, further accelerating the hydrolysis of the polyamide resin (A). Therefore, heating of the polyamide resin (A) by the heat generated by the discharge is further suppressed, and tracking fracture can be further suppressed.

[0054] In order to further improve the tracking resistance, it is effective to increase the content of the phosphorus compound (B). However, as described above, it has been newly discovered that in a polyamide resin composition containing glass fiber (C) containing a surface treatment agent or a sizing agent, if the content of the phosphorus compound (B) is too high, the mechanical strength (particularly the bending strength) of the polyamide resin composition decreases.

[0055] Generally, when a polyamide resin composition is reinforced with glass fibers, the glass fibers are often treated with a surface treatment agent or a sizing agent to improve the dispersibility of the glass fibers in the polyamide resin composition or to enhance the adhesion between the glass fibers and the polyamide resin at the interface between the glass fibers and the polyamide resin. In this embodiment, the glass fibers (C) also contain a surface treatment agent or a sizing agent, and therefore, during kneading of the polyamide resin composition, the surface treatment agent or sizing agent possessed by the glass fibers (C) or the functional groups formed on the surface of the glass fibers (C) by them interact or react with the terminal amino groups or terminal carboxylic acid groups of the polyamide resin (A). This improves the dispersibility of the glass fibers (C) in the polyamide resin (A) and also improves the adhesion between the glass fibers (C) and the polyamide resin (A). As a result, the reinforcing effect of the glass fibers (C) is excellent, and the mechanical strength, for example, bending strength, of the molded article obtained by molding the polyamide resin composition is improved.

[0056] Here, if the content of the phosphorus compound (B) is increased, the interaction or reaction site between the surface treatment agent or sizing agent of the glass fiber (C), or the functional group formed on the surface of the glass fiber (C) by them, and the terminal amino group or terminal carboxylic acid group of the polyamide resin (A) becomes easily broken by attack by the phosphorus compound (B). This becomes more pronounced when the phosphorus compound (B) contains a compound having a -P(=O)- structure or a compound having a -P(=O)-O- structure. This reduces the dispersibility of the glass fiber (C) in the polyamide resin (A). Alternatively, the adhesion between the glass fiber (C) and the polyamide resin (A) decreases. As a result, it is believed that the bending strength of the molded article obtained by molding the polyamide resin composition decreases.

[0057] In particular, when a polyamide having a high melting point is used as the polyamide resin (A), the polyamide resin composition is heated to a high temperature during melt-kneading or molding in the production of the polyamide resin composition, and when the polyamide resin composition is heated to a high temperature, attack by the phosphorus compound (B) is more likely to occur, resulting in a more significant decrease in bending strength.

[0058] For these reasons, in this embodiment, the content of the phosphorus compound (B) in the entire polyamide resin composition is appropriately reduced. Specifically, the content of phosphorus elements in the polyamide resin composition (including phosphorus elements derived from the phosphorus compound (B)) is set to 500 ppm by mass or more and 10,000 ppm by mass or less, relative to the total amount of the polyamide resin composition. When the phosphorus content is 10,000 ppm by mass or less, the tracking resistance can be sufficiently improved while maintaining good mechanical strength of the molded article. When the phosphorus content is 500 ppm by mass or more, the tracking resistance can be sufficiently improved. From the same viewpoint, the content of the phosphorus element in the polyamide resin composition is preferably 1000 mass ppm or more and 9000 mass ppm or less, more preferably 2000 mass ppm or more and 8000 mass ppm or less, still more preferably 2200 mass ppm or more and 6200 mass ppm or less, and particularly preferably 4000 mass ppm or more and 6200 mass ppm or less, relative to the total amount of the polyamide resin composition.

[0059] The phosphorus content of the polyamide resin composition can be measured by high-frequency inductively coupled plasma (ICP) emission spectrometry at a wavelength of 213.618 (nm) using, for example, an IRIS / IP device manufactured by Thermo Jarrell Ash.

[0060] In the polyamide resin composition or a molded article obtained by molding the polyamide resin composition, the phosphorus compound (B) and the polyamide resin (A) are preferably thermally connected. Also, in the polyamide resin composition or a molded article obtained by molding the polyamide resin composition, the phosphorus compound (B) is preferably in direct contact with the polyamide resin (A). This is because the thermal or direct contact between the phosphorus compound (B) and the polyamide resin (A) makes it easier to more efficiently hydrolyze the polyamide resin (A) by the phosphorus compound (B) when a discharge occurs.

[0061] As described above, the phosphorus compound (B) preferably contains a phosphinate compound. The phosphinate compound is preferably one or more selected from the group consisting of compounds represented by formula (I) or formula (II) or condensates thereof.

[0062] In formulas (I) and (II), R １ and R ２ are each a C1 to C6 alkyl group or an aryl group. ３ is a C1-C10 alkylene group, a C6-C10 arylene group, a C6-C10 alkylarylene group, or a C6-C10 arylalkylene group. M is one selected from the group consisting of Mg, Ca, Al, Sb, Sn, Ge, Ti, Zn, Fe, Zr, Ce, Bi, Sr, Mn, Li, Na, K, and a protonated nitrogen base. m is an integer of 1 to 4, n is an integer of 1 to 4, and x is an integer of 1 to 4.

[0063] Specific examples of the phosphinate compound 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, and calcium methanedi(methylphosphinate). Examples of the methylphosphinate include calcium, magnesium methane di(methylphosphinate), aluminum methane di(methylphosphinate), zinc methane di(methylphosphinate), calcium benzene-1,4-(dimethylphosphinate), magnesium benzene-1,4-(dimethylphosphinate), aluminum benzene-1,4-(dimethylphosphinate), zinc benzene-1,4-(dimethylphosphinate), calcium methylphenylphosphinate, magnesium methylphenylphosphinate, aluminum methylphenylphosphinate, zinc methylphenylphosphinate, calcium diphenylphosphinate, magnesium diphenylphosphinate, aluminum diphenylphosphinate, and zinc diphenylphosphinate. Preferred are calcium dimethylphosphinate, aluminum dimethylphosphinate, zinc dimethylphosphinate, calcium ethylmethylphosphinate, aluminum ethylmethylphosphinate, zinc ethylmethylphosphinate, calcium diethylphosphinate, aluminum diethylphosphinate, and zinc diethylphosphinate; more preferred is aluminum diethylphosphinate. One of the causes of tracking failure is carbonization of the polyamide resin composition, and therefore, when the aromatic ring concentration in the polyamide resin composition is high, tracking failure tends to occur more easily. However, since the phosphorus compound (B) does not contain an aromatic ring, it is not necessary to increase the aromatic ring concentration in the polyamide resin composition by using the phosphorus compound (B).Furthermore, if the phosphorus compound (B) has a hydroxyl group, the phosphorus compound (B) is likely to interact with or attack the terminal amino group or terminal carboxylic acid group of the polyamide resin (A) or the terminal amino group or carboxylic acid group of the surface treatment agent or sizing agent of the glass fiber (C) or the functional group formed on the surface of the glass fiber (C). Therefore, it is preferable that the phosphorus compound (B) does not have a hydroxyl group. From the above viewpoint, it is particularly preferable that the phosphorus compound (B) contains aluminum diethylphosphinate.

[0064] Representative examples of the phosphorus compound (B) include EXOLIT OP1230 and OP930 manufactured by Clariant Japan KK

[0065] The average particle size (D50) of the phosphorus compound (B) is not particularly limited, but is preferably 5 μm or more and 100 μm or less, more preferably 10 μm or more and 80 μm or less, even more preferably 20 μm or more and 60 μm or less, and particularly preferably 25 μm or more and 45 μm or less. When the average particle size of the phosphorus compound (B) is 5 μm or more, the specific surface area of ​​the phosphorus compound (B) can be appropriately reduced, thereby suppressing excessive attack by the phosphorus compound (B) on the interaction or reaction site between the polyamide resin (A) and the glass fiber (C) during melt-kneading or molding in producing the polyamide resin composition, and as a result, it is easier to suppress a decrease in bending strength. When the average particle size of the phosphorus compound (B) is 100 μm or less, the specific surface area of ​​the phosphorus compound (B) can be appropriately increased, thereby easily achieving the effect of suppressing tracking fracture without adding too much phosphorus compound (B). The average particle size of the phosphorus compound (B) can be measured by dynamic light scattering.

[0066] The content of the phosphorus compound (B) in the polyamide resin composition varies depending on the composition of the polyamide resin composition, but may be within the above-mentioned range of phosphorus element content. For example, it is preferably 0.5% by mass or more but less than 5% by mass, more preferably 0.75% by mass or more but less than 4.5% by mass, even more preferably 1% by mass or more but less than 4% by mass, and particularly preferably 2% by mass or more but less than 4% by mass, relative to the total amount of the polyamide resin composition. The higher the content of the phosphorus compound (B), the more the tracking resistance of the polyamide resin composition can be improved. The lower the content of the phosphorus compound (B), the more the decrease in mechanical strength of the molded article can be reduced.

[0067] From the same viewpoint as above, the content of the phosphorus compound (B) in the polyamide resin composition is preferably 0.5% by mass or more and 10% by mass or less, more preferably 0.5% by mass or more and 8% by mass or less, even more preferably 1% by mass or more and 7% by mass or less, and particularly preferably 2% by mass or more and 6% by mass or less, relative to the polyamide resin (A).

[0068] 1-3. Glass Fiber (C) The type of glass fiber (C) is not particularly limited as long as it is used to reinforce resins, and may be chopped strands or milled fibers with shorter fiber lengths. The cross-sectional shape of the glass fiber may be circular or non-circular, such as elliptical or oval.

[0069] The glass fibers (C) may have an average fiber length of, for example, 1 μm to 20 mm, preferably 5 μm to 10 mm, from the viewpoint of improving the moldability of the polyamide resin composition and the mechanical strength and heat resistance of the resulting molded article. The aspect ratio of the glass fibers may be, for example, 5 to 2,000, preferably 30 to 600.

[0070] The average fiber length and average fiber diameter of the glass fibers (C) can be measured by the following method. 1) A polyamide resin composition is dissolved in a hexafluoroisopropanol / chloroform solution (0.1 / 0.9% by volume), and then filtered to obtain a filtrate. 2) The filtrate obtained in 1) is dispersed in water, and the fiber length (Li) and fiber diameter (di) of each of 300 randomly selected fibers are measured using an optical microscope (magnification: 50x). The number of fibers having a fiber length of Li is designated as qi, and the weight average length (Lw) is calculated based on the following formula, which is the average fiber length of the glass fibers. Weight average length (Lw) = (Σqi × Li ２ ) / (Σqi×Li) Similarly, the number of fibers having a fiber diameter Di is taken as ri, and the weight average diameter (Dw) is calculated based on the following formula, which is the average fiber diameter of the glass fibers. Weight average diameter (Dw)=(Σri×Di ２ ) / (Σri × Di)

[0071] The glass fiber (C) contains a surface treatment agent or a sizing agent.

[0072] The surface treatment agent or sizing agent may be any known surface treatment agent or sizing agent used for glass fibers to be blended into a polyamide resin composition, and examples of the surface treatment agent or sizing agent include coupling agents such as silane coupling agents, titanium coupling agents, and aluminate coupling agents, epoxy compounds, urethane compounds, carboxylic acid compounds, urethane / maleic acid-modified compounds, and urethane / amine-modified compounds.

[0073] The surface treatment agent or sizing agent preferably has an acidic group. That is, the surface treatment agent or sizing agent preferably contains a compound having an acidic group. When the surface treatment agent or sizing agent has an acidic group, interaction or reaction is likely to occur between the glass fiber (C) and the terminal amino group of the polyamide resin (A). Therefore, the dispersibility of the glass fiber (C) in the polyamide resin (A) is further improved, and the adhesion between the glass fiber (C) and the polyamide resin (A) is further improved. As a result, the reinforcing effect of the glass fiber (C) is more effectively obtained, and the mechanical strength, such as bending strength, of the molded article obtained by molding the polyamide resin composition is further improved. Furthermore, when the surface treatment agent or sizing agent has an acidic group, the interaction between the acidic group and the terminal amino group of the polyamide resin (A) is particularly likely to be inhibited by the phosphorus compound (B). Therefore, the effect of appropriately reducing the content of the phosphorus compound (B) in the polyamide resin composition becomes more pronounced.

[0074] Examples of the acidic group include a carboxy group, an acid anhydride group, a carboxylic acid ester group, and a sulfonic acid group. Among these, the carboxy group, the acid anhydride group, and the carboxylic acid ester group are preferred, and the carboxy group and the acid anhydride group are more preferred. The carboxylic acid ester group may be a functional group derived from a carboxylic acid ester.

[0075] Examples of surface treatment agents having an acidic group include silane coupling agents containing an acid anhydride group, such as 3-trimethoxysilylpropylsuccinic anhydride.

[0076] Examples of sizing agents having an acidic group include sizing agents containing a homopolymer of an unsaturated carboxylic acid or an anhydride thereof, or a copolymer of an unsaturated carboxylic acid or an anhydride thereof with an unsaturated monomer.

[0077] Examples of unsaturated carboxylic acids include acrylic acid, methacrylic acid, cinnamic acid, itaconic acid, fumaric acid, mesaconic acid, citraconic acid, and maleic acid. Examples of anhydrides of unsaturated carboxylic acids include maleic anhydride, itaconic anhydride, and dodecenylsuccinic anhydride. Of these, acrylic acid, methacrylic acid, maleic acid, and maleic anhydride are preferred.

[0078] Examples of unsaturated monomers include styrene, butadiene, acrylonitrile, vinyl acetate, methyl acrylate, ethyl acrylate, methyl methacrylate, ethyl methacrylate, methylstyrene, ethylene, propylene, butylene, isobutylene, vinyl ether, etc. Among these, methyl acrylate and methyl methacrylate are preferred, and it is more preferred to include both methyl acrylate and methyl methacrylate.

[0079] When the sizing agent contains a copolymer of an unsaturated carboxylic acid or anhydride thereof and an unsaturated monomer, the ratio of the unsaturated carboxylic acid or anhydride to the copolymer is preferably 20% by mass or more and 60% by mass or less. When this ratio is 20% by mass or more, the effect of improving the mechanical strength of the polyamide resin composition is remarkable by increasing the chemical interaction with the polyamide resin (A) via the acidic groups (carboxy groups). When this ratio is 60% by mass or less, the chemical interaction with the polyamide resin (A) via the acidic groups is unlikely to be excessive, and the fluidity of the polyamide resin composition during molding is further unlikely to be impaired.

[0080] The weight-average molecular weight (Mw) of the homopolymer or copolymer is preferably 3,000 or more and 60,000 or less. When the weight-average molecular weight of the homopolymer or copolymer is 3,000 or more, the molecular weight (chain length) of the homopolymer or copolymer is increased, which facilitates entanglement with the molecular chain of the polyamide resin (A) (enhancing physical interaction), thereby further improving the mechanical strength of the polyamide resin composition. On the other hand, when the weight-average molecular weight of the homopolymer or copolymer is 60,000 or less, the dispersibility of the glass fiber (C) in the polyamide resin (A) can be further improved. From the above viewpoint, the weight-average molecular weight of the homopolymer or copolymer is preferably 10,000 or more and 50,000 or less, and more preferably 20,000 or more and 50,000 or less. The weight-average molecular weight of the homopolymer or copolymer is a value measured by gel permeation chromatography (GPC) and calculated using polystyrene as a standard substance.

[0081] The homopolymer or copolymer may be used in combination with other resins such as urethane resins and epoxy resins. It is particularly preferred that the homopolymer or copolymer be combined with a urethane resin. That is, the sizing agent preferably contains the homopolymer or copolymer and a urethane resin.

[0082] Specifically, the urethane bond site (—NHCO—) of the urethane resin has a moderately good affinity with the terminal carboxy group of the polyamide resin (A), and therefore, the glass fiber (C) and the polyamide resin (A) can easily interact with each other. Therefore, even if the phosphorus compound (B) is contained, the affinity between the glass fiber (C) and the polyamide resin (A) can be more easily increased, and the glass fiber (C) can be more easily dispersed in the polyamide resin (A).

[0083] Examples of urethane resins include urethane resins synthesized from isocyanates such as m-xylylene diisocyanate (XDI), 4,4'-methylenebis(cyclohexyl isocyanate) (HMDI) and isophorone diisocyanate (IPDI), and polyester- or polyether-based diols.

[0084] (Manufacturing Method) Glass fibers containing a surface treatment agent or a sizing agent can be obtained, for example, during the glass fiber manufacturing process, by applying (applying) the surface treatment agent or the sizing agent to a fiber strand using a known method such as a roller-type applicator, and then drying and allowing it to react.

[0085] The amount of the surface treatment agent or sizing agent attached is preferably 0.2 to 3 parts by mass, more preferably 0.2 to 2 parts by mass, and even more preferably 0.3 to 2 parts by mass, based on 100 parts by mass of the glass fibers (C). When the amount is 0.2 parts by mass or more, the bundling ability of the glass fibers (C) is further improved. When the amount is 2 parts by mass or less, the thermal stability of the polyamide resin composition is further improved.

[0086] The content of glass fiber (C) in the polyamide resin composition is preferably 15% by mass or more and 70% by mass or less, more preferably 25% by mass or more and 60% by mass or less, and even more preferably 30% by mass or more and 50% by mass or less, based on the total amount of the polyamide resin composition. The higher the content of glass fiber (C), the higher the mechanical strength of the polyamide resin composition can be. The lower the content of glass fiber (C), the less the decrease in mechanical strength of the molded article due to the addition of phosphorus compound (B).

[0087] The polyamide resin composition may contain other known components. The content of the other components is preferably 0% by mass or more and 10% by mass or less, and more preferably 0.5% by mass or more and 10% by mass or less, relative to the total amount of the polyamide resin composition.

[0088] Examples of other components include colorants, crystal nucleating agents, lubricants, corrosion resistance improvers, anti-drip agents, ion scavengers, elastomers (rubbers), antistatic agents, mold release agents, antioxidants (phenols, amines, sulfur compounds, phosphorus compounds, etc.), heat stabilizers (lactone compounds, vitamin E compounds, hydroquinones, copper halides, iodine compounds, etc.), light stabilizers (benzotriazoles, triazines, benzophenones, benzoates, hindered amines, oxanilides, etc.), other polymers (polyolefins, olefin copolymers such as ethylene-propylene copolymers, ethylene-1-butene copolymers, olefin copolymers such as propylene-1-butene copolymers, polystyrene, polyamide, polycarbonate, polyacetal, polysulfone, polyphenylene oxide, fluororesin, silicone resin, and LCP).

[0089] The colorant imparts a desired color tone to the molded article. The colorant is not particularly limited, but may be a pigment. Examples of the pigment include inorganic pigments such as carbon black, alumina, titanium oxide, chromium oxide, iron oxide, zinc oxide, and barium sulfate; and organic pigments such as azo pigments, phthalocyanine pigments, quinacridone pigments, perylene pigments, anthraquinone pigments, thioindigo pigments, and indanthrene pigments.

[0090] The content of the colorant is preferably 0.01% by mass or more and 5% by mass or less, and more preferably 0.1% by mass or more and 2% by mass or less, based on the total amount of the polyamide resin composition.

[0091] The crystal nucleating agent can increase the crystallinity of the molded body. Examples of the crystal nucleating agent include metal salt compounds such as sodium 2,2-methylenebis(4,6-di-t-butylphenyl)phosphate, aluminum tris(p-t-butylbenzoate), and stearates; sorbitol compounds such as bis(p-methylbenzylidene)sorbitol and bis(4-ethylbenzylidene)sorbitol; and inorganic substances such as talc, calcium carbonate, and hydrotalcite. Of these, talc is preferred from the viewpoint of further increasing the crystallinity of the molded body. These crystal nucleating agents may be used alone or in combination of two or more.

[0092] The content of the nucleating agent is preferably 0.1% by mass or more and 5% by mass or less, and more preferably 0.1% by mass or more and 3% by mass or less, based on the total amount of the polyamide resin composition. When the content of the nucleating agent is within the above range, the crystallinity of the molded body is more likely to be increased, and higher mechanical strength is more likely to be obtained.

[0093] The lubricant improves the injection flowability of the polyamide resin composition and improves the appearance of the resulting molded article. The lubricant can be a metal salt of a fatty acid such as a metal salt of an oxycarboxylic acid or a metal salt of a higher fatty acid.

[0094] The oxycarboxylic acid constituting the oxycarboxylic acid metal salt may be an aliphatic oxycarboxylic acid or an aromatic oxycarboxylic acid. Examples of aliphatic oxycarboxylic acids include aliphatic oxycarboxylic acids having 10 to 30 carbon atoms, such as α-hydroxymyristic acid, α-hydroxypalmitic acid, α-hydroxystearic acid, α-hydroxyeicosanoic acid, α-hydroxydocosanoic acid, α-hydroxytetraeicosanoic acid, α-hydroxyhexaeicosanoic acid, α-hydroxyoctaeicosanoic acid, α-hydroxytriacontanoic acid, β-hydroxymyristic acid, 10-hydroxydecanoic acid, 15-hydroxypentadecanoic acid, 16-hydroxyhexadecanoic acid, 12-hydroxystearic acid, and ricinoleic acid. Examples of aromatic oxycarboxylic acids include salicylic acid, m-hydroxybenzoic acid, p-hydroxybenzoic acid, gallic acid, mandelic acid, and trovic acid.

[0095] Examples of the metal constituting the metal oxycarboxylic acid salt include alkali metals such as lithium, and alkaline earth metals such as magnesium, calcium, and barium.

[0096] Of these, the metal oxycarboxylic acid salt is preferably a metal salt of 12-hydroxystearic acid, and more preferably magnesium 12-hydroxystearate and calcium 12-hydroxystearate.

[0097] Examples of higher fatty acids that constitute higher fatty acid metal salts include higher fatty acids having 15 to 30 carbon atoms, such as stearic acid, oleic acid, behenic acid, behenic acid, and montanic acid.

[0098] Examples of metals constituting the higher fatty acid metal salts include calcium, magnesium, barium, lithium, aluminum, zinc, sodium, and potassium.

[0099] Of these, preferred higher fatty acid metal salts are calcium stearate, magnesium stearate, barium stearate, calcium behenate, sodium montanate, calcium montanate, and the like.

[0100] The content of the lubricant is preferably 0.01% by mass or more and 1.3% by mass or less relative to the total amount of the polyamide resin composition. When the content of the lubricant is 0.01% by mass or more, the fluidity during molding is likely to be improved, and the appearance of the obtained molded product is likely to be improved. When the content of the lubricant is 1.3% by mass or less, gas due to decomposition of the lubricant is less likely to be generated during molding, and the appearance of the product is likely to be better.

[0101] The polyamide resin composition can be produced by a known resin kneading method, for example, by mixing the polyamide resin (A), the phosphorus compound (B), the glass fiber (C), and, if necessary, other components, using a Henschel mixer, a V blender, a ribbon blender, or a tumbler blender, or by mixing and then melt-kneading the mixture using a single-screw extruder, a multi-screw extruder, a kneader, or a Banbury mixer, followed by granulation or pulverization.

[0102] 2. Uses of Polyamide Resin Composition The polyamide resin composition of the present invention can be molded into various molded articles by known molding methods such as compression molding, injection molding, and extrusion molding.

[0103] Molded articles of the polyamide resin composition can be used in various applications. In particular, since the polyamide resin composition has good mechanical strength and tracking resistance, it can be preferably used in fields requiring these properties or in the field of precision molding. Examples of such applications include various molded articles for electrical and electronic parts such as automotive electrical components, connectors, switches, jacks, plugs, breakers, electromagnetic switches, current interrupters, and LED reflecting materials, as well as automotive parts.

[0104] The present invention will be described below with reference to examples, which should not be construed as limiting the scope of the present invention.

[0105] In the following experiments, the melting point (Tm), glass transition temperature (Tg), intrinsic viscosity, heat of fusion and amount of terminal amino groups of the polyamide resin were measured by the following methods.

[0106] (Melting Point (Tm), Glass Transition Temperature (Tg), and Heat of Fusion (ΔH)) The heat of fusion (ΔH), melting point (Tm), and glass transition temperature (Tg) of the polyamide resin were measured using a differential scanning calorimeter (DSC220C, manufactured by Seiko Instruments Inc.).

[0107] Specifically, approximately 5 mg of polyamide resin was sealed in a measuring aluminum pan and heated from room temperature to 350°C at 10°C / min. To completely melt the resin, it was held at 350°C for 3 minutes and then cooled to 30°C at 10°C / min. After leaving it at 30°C for 5 minutes, it was heated a second time to 350°C at 10°C / min. The temperature (°C) of the endothermic peak during this second heating was taken as the melting point (Tm) of the polyamide resin, and the inflection point corresponding to the glass transition was taken as the glass transition temperature (Tg). The heat of fusion (ΔH) was determined from the area of ​​the endothermic peak during the second heating process in accordance with JIS K7122.

[0108] (Intrinsic Viscosity [η]) The intrinsic viscosity [η] of a polyamide resin was determined by dissolving 0.5 g of polyamide resin in 50 ml of a 96.5% sulfuric acid solution, measuring the number of seconds it took for the resulting solution to flow down under conditions of 25°C ± 0.05°C using an Ubbelohde viscometer, and calculating the intrinsic viscosity [η] = ηSP / (C(1 + 0.205ηSP)) where [η]: intrinsic viscosity (dl / g), ηSP: specific viscosity, C: sample concentration (g / dl), t: number of seconds (seconds) for the sample solution to flow down, and t0: number of seconds (seconds) for blank sulfuric acid to flow down. ηSP = (t - t0) / t0

[0109] (Amount of Terminal Amino Groups, Amount of Terminal Carboxylic Acid Groups) The amounts of terminal amino groups and terminal carboxylic acid groups of the polyamide resin were measured by NMR. 30 mg of polyamide resin was dissolved in 0.5 mL of deuterated hexafluoroisopropanol (HFIP) to prepare a sample for NMR measurement. NMR measurement was performed on the sample using an ECA-500 nuclear magnetic resonance spectrometer (500 MHz-NMR) (manufactured by JEOL Ltd.). The amount of terminal carboxylic acid structures (μeq / g) was calculated as a numerical value per part by mass of polyamide resin from the ratio of the peak area of ​​the methylene group hydrogen adjacent to the terminal carboxylic acid structure to the peak area of ​​the methylene group hydrogen adjacent to the amide structure in the obtained spectrum. The amount of terminal amine structures (μeq / g) was calculated as a numerical value per part by mass of polyamide resin from the peak area derived from the terminal amine structure and the peak area derived from the methylene group hydrogen of the carboxylic acid component constituting the amide structure. The obtained value was then converted to mmol / kg.

[0110] 1. Preparation of Materials 1-1. Polyamide Resin (A) Synthesis of Polyamide Resin (A1) 2,800 g (24.1 mol) of 1,6-hexanediamine, 2,774 g (16.7 mol) of terephthalic acid, 1,196 g (7.2 mol) of isophthalic acid, 36.6 g (0.30 mol) of benzoic acid, 5.7 g of sodium hypophosphite monohydrate, and 545 g of distilled water were placed in a 13.6 L autoclave and purged with nitrogen. Stirring was initiated at 190°C, and the internal temperature was raised to 250°C over three hours. At this time, the internal pressure of the autoclave was increased to 3.03 MPa. After continuing the reaction for one hour, the mixture was released into the atmosphere through a spray nozzle installed at the bottom of the autoclave, and the low-order condensation product was extracted. The low-order condensation product was then cooled to room temperature, pulverized in a pulverizer to a particle size of 1.5 mm or less, and dried at 110°C for 24 hours. The water content of the obtained low-order condensate was 4100 ppm, and the intrinsic viscosity [η] was 0.15 dl / g. Next, this low-order condensate was placed in a tray-type solid-state polymerization reactor, and after nitrogen substitution, the temperature was raised to 180°C over about 1 hour and 30 minutes. Thereafter, the reaction was allowed to proceed for 1 hour and 30 minutes, and the temperature was lowered to room temperature. The intrinsic viscosity [η] of the obtained prepolymer was 0.20 dl / g. Thereafter, the obtained prepolymer was melt-polymerized in a twin-screw extruder with a screw diameter of 30 mm and L / D = 36, at a barrel setting temperature of 330°C, a screw rotation speed of 200 rpm, and a resin feed rate of 6 kg / h, to obtain a polyamide resin (A1).

[0111] The resulting polyamide resin (A1) had an intrinsic viscosity of 1.0 dl / g, a melting point (Tm) of 330° C., a glass transition temperature (Tg) of 125° C., and a heat of fusion (ΔH) of 50 J / g. The polyamide resin (A1) also had a terminal amino group content of 20 mmol / kg and a terminal carboxy group content of 140 mmol / kg.

[0112] 1-2. Phosphorus Compound (B) Phosphinate compound (EXOLIT OP1230 manufactured by Clariant Japan, phosphorus content: 23.8 mass%, aluminum diethylphosphinate, average particle size (D50): 10 to 50 μm)

[0113] 1-3. Glass fiber (C) Glass fiber surface-modified by acid modification (FT-2A manufactured by Owens Corning, average fiber diameter: 10.5 μm, average fiber length: 3 mm, sizing agent: mixture of polymer of maleic acid-containing unsaturated vinyl monomer and urethane resin)

[0114] 1-4. Colorant (D) A masterbatch containing 94% by mass of polyamide resin (A1) and 6% by mass of pigment was used as the resin.

[0115] 1-5. Nucleating agent (E) Talc (fine particle talc, average particle size 6 μm)

[0116] 1-6. Lubricant (F) Sodium montanate

[0117] 2. Preparation of Polyamide Resin Compositions (Examples 1 to 4, Comparative Examples 1 to 3) The above materials were mixed in a tumbler blender in the composition ratios (units: parts by mass) shown in Table 1, and melt-kneaded using a 30 mmφ vented twin-screw extruder at a cylinder temperature of 300 to 335°C. The kneaded mixture was then extruded into strands and cooled in a water tank. The strands were then taken up in a pelletizer and cut to obtain pellets of polyamide resin compositions.

[0118] The phosphorus element content of the polyamide resin composition was measured by high-frequency inductively coupled plasma (ICP) emission spectrometry at a wavelength of 213.618 (nm) using an IRIS / IP device manufactured by Thermo Jarrell Ash.

[0119] 3. Evaluation The obtained polyamide resin compositions were evaluated according to the following criteria.

[0120] 3-1. Tracking Resistance The resulting polyamide resin composition was injection molded under the following conditions to prepare 120 mm x 130 mm x 3 mm test specimens. Molding machine: SE75EV-A, manufactured by Sumitomo Heavy Industries, Ltd. Molding machine cylinder temperature: 335°C Mold temperature: 160°C The tracking resistance of the prepared test specimens was evaluated in accordance with IEC 60112. Specifically, using a tracking resistance tester, manufactured by Yamayo Test Instruments, model YST-112, at 23±2°C, 45-50% RH, and a measurement voltage range of 100-1000 V, 50 drops of test liquid A (0.1% aqueous ammonium chloride solution) were added dropwise every 30 seconds to check whether tracking occurred on the test specimens. This procedure was repeated at different voltages, and the maximum voltage (CTI) at which the test specimens did not break down after 50 drops without tracking was determined. If tracking did not occur even after 100 drops were dropped at a voltage 25 V lower than this maximum voltage, it was judged as passing. The higher this maximum voltage, the better the tracking resistance. If the maximum voltage was 550 V or higher, it was judged as good.

[0121] 3-2. Flow Length The obtained polyamide resin composition was injected into a bar flow mold having a width of 10 mm and a thickness of 0.5 mm under the following conditions, and the flow length (mm) of the polyamide resin composition in the mold was measured. Note that the longer the flow length, the better the injection fluidity. Molding machine: EC75N-2A manufactured by Toshiba Machine Co., Ltd. Injection setting pressure: 2000 kg / cm ２ Molding machine cylinder temperature: 335°C Mold temperature: 160°C

[0122] 3-3. Maintenance rate of flow length before and after addition of phosphorus compound The maintenance rate of flow length before and after addition of phosphorus compound (B) was calculated by comparing the flow length of the polyamide resin composition containing the phosphorus compound (B) with the flow length of a polyamide resin composition containing the same amount of additives but not containing the phosphorus compound (B).

[0123] 3-4. Flexural Strength The obtained polyamide resin composition was injection molded under the following conditions to prepare a 3.2 mm thick test piece. Molding machine: SE75EV-A manufactured by Sumitomo Heavy Industries, Ltd. Molding machine cylinder temperature: 335°C Mold temperature: 160°C The prepared test piece was left to stand for 24 hours at a temperature of 23°C in a nitrogen atmosphere. Next, a bending test was performed using a bending tester (AB5 manufactured by NTESCO Corporation) in an atmosphere of 23°C and 50% relative humidity, with a span of 51 mm and a bending speed of 12.7 mm / min, to measure the flexural strength.

[0124] 3-5. Percentage of flexural strength retention before and after incorporation of phosphorus compound The flexural strength of the polyamide resin composition containing the phosphorus compound (B) was compared with the flexural strength of a polyamide resin composition containing the same amount of additives but not containing the phosphorus compound (B), and the percent of flexural strength retention before and after incorporation of the phosphorus compound (B) was calculated.

[0125] The composition of the prepared polyamide resin composition, the flow length and its retention rate, and the flexural strength and its retention rate are shown in Table 1. A graph plotting the obtained results is shown in Figure 1. In the graph of Figure 1, the horizontal axis represents the phosphorus content (ppm by mass) in the polyamide resin composition, the left vertical axis represents the flexural strength (MPa), and the right vertical axis represents the maximum voltage CTI (V) at which tracking breakdown does not occur.

[0126]

[0127] As is clear from Table 1, the polyamide resin composition of Comparative Example 1, which does not contain a phosphorus compound (B), exhibits low tracking resistance. On the other hand, the polyamide resin compositions of Comparative Examples 2 and 3, which contain a large amount of phosphorus compound (B) so that the phosphorus content in the polyamide resin composition exceeds 10,000 ppm by mass, exhibit high tracking resistance but low flexural strength retention. In contrast, the polyamide resin compositions of Examples 1 to 4, which contain a small amount of phosphorus compound (B) so that the phosphorus content is 10,000 ppm by mass or less, exhibit high tracking resistance while maintaining high flexural strength.

[0128] From Figure 1 in which these results are plotted, it can be seen that when the phosphorus content is increased beyond about 8000 ppm by mass, the bending strength decreases rapidly, whereas when the phosphorus content is 8000 ppm by mass or less, the decrease in bending strength is significantly small (while maintaining a CTI of 550 V or more).

[0129] From these findings, it can be seen that by including a small amount of phosphorus compound (B) so that the phosphorus content is 10,000 ppm by mass or less, and more preferably by including a small amount of phosphorus compound (B) so that the phosphorus content is 8,000 ppm by mass or less, the flexural strength of the polyamide resin composition can be maintained at a good level while improving the tracking resistance.

[0130] This application claims priority from Japanese Patent Application No. 2023-16026, filed February 6, 2023. The contents of the specification and drawings of that application are incorporated herein by reference in their entirety.

[0131] The polyamide resin composition of the present invention can provide a polyamide resin composition having high tracking resistance while maintaining good mechanical strength. Therefore, the present invention is expected to broaden the applicability of polyamide resins to various applications and contribute to the further popularization of polyamide resins.

Claims

1. a polyamide resin (A) having a melting point of 280°C or higher as measured by a differential scanning calorimeter (DSC); a phosphorus compound (B); Glass fibers (C) containing a surface treatment agent or a sizing agent; A polyamide resin composition comprising: The content of phosphorus element in the polyamide resin composition is 500 ppm by mass or more and 10,000 ppm by mass or less with respect to the polyamide resin composition. Polyamide resin composition.

2. The surface treatment agent or sizing agent has an acidic group. The polyamide resin composition according to claim 1.

3. the acidic group is a carboxy group, an acid anhydride group, or a carboxylic acid ester group; The polyamide resin composition according to claim 2.

4. The surface treatment agent or the sizing agent contains a compound having an acidic group and a urethane resin. The polyamide resin composition according to claim 2.

5. The phosphorus compound (B) includes a phosphinate compound. The polyamide resin composition according to claim 1.

6. The phosphinate compound is at least one selected from the group consisting of compounds represented by formula (I) or formula (II), or condensates thereof: The polyamide resin composition according to claim 5. 【Chemical 1】 [In the formula, R １ and R ２ are each a C1 to C6 alkyl group or an aryl group, R ３ is a C1 to C10 alkylene group, a C6 to C10 arylene group, a C6 to C10 alkylarylene group, or a C6 to C10 arylalkylene group, M is one selected from the group consisting of Mg, Ca, Al, Sb, Sn, Ge, Ti, Zn, Fe, Zr, Ce, Bi, Sr, Mn, Li, Na, K, and protonated nitrogen bases; m represents an integer of 1 to 4, n represents an integer of 1 to 4, and x represents an integer of 1 to 4.

7. The phosphorus compound (B) includes aluminum diethylphosphinate. The polyamide resin composition according to claim 1.

8. The polyamide resin (A) has a heat of fusion (ΔH) of 10 J / g or more as measured by differential scanning calorimetry (DSC). The polyamide resin composition according to claim 1.

9. The polyamide resin (A) is Contains a component unit (Aa) derived from a dicarboxylic acid and a component unit (Ab) derived from a diamine, The dicarboxylic acid-derived component unit (Aa) includes an aromatic dicarboxylic acid-derived component unit. The polyamide resin composition according to claim 1.

10. The polyamide resin (A) is Contains a component unit (Aa) derived from a dicarboxylic acid and a component unit (Ab) derived from a diamine, The dicarboxylic acid-derived component units (Aa) include terephthalic acid-derived component units and isophthalic acid-derived component units. The polyamide resin composition according to claim 1.

11. The content of the phosphorus compound (B) is 0.5% by mass or more and less than 5% by mass with respect to the polyamide resin composition. The polyamide resin composition according to claim 1.

12. The content of the glass fiber (C) is 25% by mass or more and 60% by mass or less relative to the polyamide resin composition. The polyamide resin composition according to claim 1.

13. A polyamide resin composition comprising the polyamide resin composition according to any one of claims 1 to 12. Molded body.

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