Polyamide resin composition and molded article

Abstract

The polyamide resin composition contains a polyamide resin (A), a phosphorus compound (B), and glass fibers (C) containing a surface treatment agent or a bundling agent. The content of elemental phosphorus in the polyamide resin composition is from 500 ppm by mass to 10000 ppm by mass (inclusive) with respect to the polyamide resin composition.

Description

Technical Field

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

[0002] Polyamide resin compositions have been widely used as materials for various parts such as clothing, industrial materials, automobiles, electrical / electronics, and industrial applications due to their excellent moldability, mechanical properties, and chemical resistance.

[0003] In order to develop properties suitable for each application, various additives may be added to the polyamide resin compositions used for these applications. For example, it is known to add reinforcing materials such as glass fibers to improve the mechanical strength of the polyamide resin compositions.

[0004] The glass fibers are sometimes treated with sizing agents or surface treatment agents for purposes such as improving dispersibility in the polyamide resin. Examples of sizing agents and surface treatment agents for glass fibers include epoxy compounds, amine compounds, urethane compounds, and carboxylic acid compounds.

[0005] In addition, flame retardants are sometimes added to impart flame retardancy. For example, Patent Document 1 discloses a resin composition comprising a specific semi-aromatic polyamide, polyphenylene ether, a phosphazene compound and a phosphinate as flame retardants, and glass fiber. This document describes the use of a phosphazene compound and a phosphinate as flame retardants to achieve excellent flame retardancy. In the examples and comparative examples of this document, the total amount of the phosphazene compound and the phosphinate in the resin composition is calculated to be approximately 8 to 15% by mass, and the phosphorus content of these compounds is 1.37% by mass at the lowest content.

[0006] In addition, Patent Document 2 discloses a flame-retardant polyamide resin composition comprising: 30-80% by weight of a polyamide resin, 1-30% by weight of an adduct of melamine and phosphoric acid, 1-30% by weight of a specific phosphinate, 0.01-5% by weight of a monoester derivative of a polyalkylene polyol and a higher fatty acid, and 5-40% by weight of an inorganic filler. The document states that the combined use of 1-30% by weight of an adduct of melamine and phosphoric acid and a specific phosphinate not only improves flame retardancy but also improves tracking resistance. In the examples and comparative examples of the document, the phosphorus content of the flame-retardant polyamide resin composition derived from the melamine polyphosphate and the phosphinate was calculated to be 1.96-3.7% by weight.

[0007] Prior art literature

[0008] Patent Literature

[0009] Patent Document 1: International Publication No. 2008 / 081878

[0010] Patent Document 2: Japanese Patent Application Laid-Open No. 2004-292531 Summary of the Invention

[0011] Problems to be solved by the invention

[0012] Furthermore, electrical and electronic components used in high-voltage environments, for example, require high tracking resistance. Research by the present inventors has shown that adding a large amount of a phosphorus compound to a polyamide resin composition can significantly improve tracking resistance. However, a new problem has been discovered: 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.

[0013] In view of these circumstances, an object of the present invention is to provide a polyamide resin composition having high tracking resistance while maintaining good mechanical strength, and a polyamide molded article comprising the polyamide resin composition.

[0014] Means for solving problems

[0015] The present invention relates to the following polyamide resin composition and molded article.

[0016] [1] A polyamide resin composition comprising: 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); and glass fiber (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 higher and 10,000 ppm by mass or lower relative to the polyamide resin composition.

[0017] [2] The polyamide resin composition according to [1], wherein the surface treatment agent or sizing agent has an acidic group.

[0018] [3] The polyamide resin composition according to [2], wherein the acidic group is a carboxyl group, an acid anhydride group, or a carboxylate group.

[0019] [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 polyurethane resin.

[0020] [5] The polyamide resin composition according to any one of [1] to [4], wherein the phosphorus compound (B) comprises a phosphinate compound.

[0021] [6] The polyamide resin composition according to [5], wherein the phosphinate compound is one or more selected from the group consisting of compounds represented by formula (I) or formula (II), or condensates thereof.

[0022] [Chemistry 1]

[0023]

[0024] [Where R 1 and R 2 are C1~C6 alkyl or aryl,

[0025] R 3 is C1-C10 alkylene, C6-C10 arylene, C6-C10 alkylarylene or C6-C10 arylalkylene,

[0026] 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,

[0027] 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.]

[0028] [7] The polyamide resin composition according to any one of [1] to [6], wherein the phosphorus compound (B) comprises aluminum diethylphosphinate.

[0029] [8] The polyamide resin composition according to any one of [1] to [7], wherein the heat of fusion (ΔH) of the polyamide resin (A) measured by differential scanning calorimetry (DSC) is 10 J / g or more.

[0030] [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 a dicarboxylic acid comprises a component unit derived from an aromatic dicarboxylic acid.

[0031]

[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 a dicarboxylic acid comprises a component unit derived from terephthalic acid and a component unit derived from isophthalic acid.

[0032]

[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.

[0033]

[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.

[0034]

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

[12] .

[0035] Effects of the Invention

[0036] According to the present invention, a polyamide resin composition having high tracking resistance while maintaining good mechanical strength, and a polyamide molded article comprising the polyamide resin composition can be provided. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] [ Figure 1 ] Figure 1 This is a graph in which the results obtained in Examples and Comparative Examples are plotted. DETAILED DESCRIPTION

[0038] 1. Polyamide resin composition

[0039] The polyamide resin composition comprises a polyamide resin (A), a phosphorus compound (B), and glass fibers (C) comprising a surface treatment agent or a sizing agent.

[0040] 1-1. Polyamide resin (A)

[0041] The polyamide resin (A) contains a component unit (Aa) derived from a dicarboxylic acid and a component unit (Ab) derived from a diamine.

[0042] [Component units derived from dicarboxylic acid (Aa)]

[0043] The dicarboxylic acid-derived component units (Aa) preferably include component units derived from an aromatic dicarboxylic acid or an alicyclic dicarboxylic acid, and more preferably include component units derived from an aromatic dicarboxylic acid. When the polyamide resin (A) includes component units derived from an aromatic dicarboxylic acid or an alicyclic dicarboxylic acid as the dicarboxylic acid-derived component units (Aa), the melting point (Tm) and crystallinity can be sufficiently improved. When the polyamide resin (A) includes component units derived from an aromatic dicarboxylic acid, the melting point (Tm) and crystallinity can be further sufficiently improved.

[0044] Examples of aromatic dicarboxylic acids include terephthalic acid, isophthalic acid, naphthalene dicarboxylic acid, and esters thereof. Examples of alicyclic dicarboxylic acids include cyclohexane dicarboxylic acid and esters thereof.

[0045] In the present embodiment, the component unit (Aa) from dicarboxylic acid preferably includes the component unit (Aa1) from terephthalic acid, naphthalene dicarboxylic acid or cyclohexane dicarboxylic acid. These component units (Aa1) are, for example, different from isophthalic acid, and can improve the crystallinity of polyamide. From the viewpoint of ensuring the crystallinity of polyamide resin, the content of these component units (Aa1) is preferably set to be greater than 20 mol % and 100 mol % or less relative to the total mole number of the component unit (Aa) from dicarboxylic acid. From the viewpoint of further improving the crystallinity of polyamide resin (A), the content of these component units (Aa1) is preferably 45 mol % or more and 100 mol % or less relative to the total mole number of the component unit (Aa) from dicarboxylic acid, more preferably 50 mol % or more and 99 mol % or less, further preferably greater than 60 mol % and 80 mol % or less. Wherein, from the viewpoint of obtaining a polyamide resin having high crystallinity and high heat resistance, the above-mentioned component unit (Aa1) is more preferably the component unit from terephthalic acid.

[0046] The component units (Aa) derived from a dicarboxylic acid may further contain component units (Aa2) derived from an aromatic dicarboxylic acid other than the above-mentioned component units (Aa1) or component units (Aa3) derived from an aliphatic dicarboxylic acid having 4 to 18 carbon atoms, within a range not impairing the effects of the present invention.

[0047] Examples of the component units (Aa2) derived from aromatic dicarboxylic acids other than terephthalic acid include component units derived from isophthalic acid and 2-methylterephthalic acid, and preferably contain component units derived from isophthalic acid. From the viewpoint of ensuring the crystallinity of the polyamide resin, when the polyamide resin (A) contains the component units (Aa2), the content of these component units (Aa2) is preferably 1 mol% or more and 50 mol% or less, more preferably 10 mol% or more and 40 mol% or less, further preferably 15 mol% or more and 40 mol% or less, and particularly preferably 20 mol% or more and 40 mol% or less, relative to the total number of moles of the component units (Aa) derived from dicarboxylic acids.

[0048] The component unit (Aa3) derived from an aliphatic dicarboxylic acid is a component unit derived from an aliphatic dicarboxylic acid having an alkylene group with 4 to 18 carbon atoms, and is preferably a structural unit derived from an aliphatic dicarboxylic acid having an alkylene group with 6 to 12 carbon atoms. Examples of aliphatic dicarboxylic acids include component units derived from 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, and preferably includes component units derived from adipic acid and sebacic acid. Among them, adipic acid and sebacic acid are preferred. From the viewpoint of ensuring the crystallinity of the polyamide resin, when the polyamide resin (A) contains the component units (Aa3), the content of these component units (Aa3) is preferably from 0 mol% to 40 mol% with respect to the total molar number of the component units (Aa) derived from dicarboxylic acid, more preferably from 0 mol% to 20 mol%, further preferably from 1 mol% to 10 mol%, and particularly preferably from 1 mol% to 5 mol%.

[0049] Among the above-mentioned component units (Aa2) and the above-mentioned component units (Aa3), from the viewpoint of being able to moderately reduce the crystallinity while maintaining the melting point of the polyamide resin (A), the component unit (Aa) derived from dicarboxylic acid preferably also contains the component unit (Aa2), and more preferably also contains the component unit derived from isophthalic acid as the component unit (Aa2).

[0050] The polyamide resin (A) may further contain a small amount of a trivalent or higher polyvalent carboxylic acid component unit such as trimellitic acid or pyromellitic acid in addition to the above-mentioned component units (Aa1), (Aa2), and (Aa3). The content of such a polyvalent carboxylic acid component unit may be 0 mol% or more and 5 mol% or less relative to the total number of moles of the component units (Aa) derived from dicarboxylic acids.

[0051] [Component unit derived from diamine (Ab)]

[0052] The component units (Ab) derived from diamine preferably include component units (Ab1) derived from a linear alkylenediamine having 4 to 18 carbon atoms, and may further include component units (Ab2) derived from an alkylenediamine having 4 to 18 carbon atoms and having a side chain alkyl group, and component units (Ab3) derived from an alicyclic diamine having 4 to 20 carbon atoms.

[0053] Regarding the diamine-derived component unit (Ab), when the total molar number of the diamine-derived component units contained in the polyamide resin (A) is 100 mol%, the amount of the component unit (Ab1) derived from a linear alkylenediamine having 4 to 18 carbon atoms is preferably 20 mol% or more and 100 mol% or less, more preferably 20 mol% or more and 80 mol% or less. When the content of the above-mentioned component unit is 20 mol% or more, the crystallization rate does not become too slow, so it is easy to moderately improve the crystallinity and mechanical strength of the polyamide resin (A). When the content of the above-mentioned component unit is 100 mol% or less, preferably 80 mol% or less, the crystallization rate of the polyamide resin (A) does not become too high, so the fluidity during molding is not easily impaired. From the same viewpoint, the content of the component unit derived from a linear aliphatic diamine is further preferably 30 mol% or more and 60 mol% or less relative to the above total.

[0054] In addition, the diamine-derived component unit (Ab) may include a component unit (Ab2) derived from an alkylene diamine 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. In this case, when the total molar number of the diamine-derived component units contained in the polyamide resin (A) is set to 100 mol%, the amount of the component unit (Ab2) derived from an alkylene diamine having 4 to 18 carbon atoms and having a side chain alkyl group, or the component unit (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 the above-mentioned component unit is 20 mol% or more, the crystallization rate of the polyamide resin (A) tends to be moderately slow, thereby easily improving the fluidity during molding. When the content of the above-mentioned component unit is 80 mol% or less, the crystallinity and mechanical strength of the polyamide resin (A) are not easily 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 based on the above total.

[0055] Examples of the component unit (Ab1) derived from a linear alkylenediamine having 4 to 18 carbon atoms include components 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. Among these, components derived from 1,6-diaminohexane, 1,8-diaminooctane, 1,10-diaminodecane, and 1,12-diaminododecane are preferred, with 1,6-diaminohexane being more preferred. Multiple types of these components may be contained in the polyamide resin (A).

[0056] Examples of the component unit (Ab2) derived from an alkylenediamine having 4 to 18 carbon atoms and having a side chain alkyl group include: 1-butyl-1,2-diaminoethane, 1,1-dimethyl-1,4-diaminobutane, 1-ethyl-1,4-diaminobutane, 1,2-dimethyl-1,4-diaminobutane, 1,3-dimethyl-1,4-diaminobutane, 1,4-dimethyl-1,4-diaminobutane, 2,3-dimethyl-1,4-diaminobutane, 2-methyl-1, ,5-diaminopentane, 2,5-dimethyl-1,6-diaminohexane, 2,4-dimethyl-1,6-diaminohexane, 3,3-dimethyl-1,6-diaminohexane, 2,2-dimethyl-1,6-diaminohexane, 2,2,4-trimethyl-1,6-diaminohexane, 2,4,4-trimethyl-1,6-diaminohexane, 2,4-diethyl-1,6-diaminohexane, 2,3-dimethyl-1,7-diaminoheptane, 2,4-dimethyl-1,7- Diaminoheptane, 2,5-dimethyl-1,7-diaminoheptane, 2,2-dimethyl-1,7-diaminoheptane, 2-methyl-4-ethyl-1,7-diaminoheptane, 2-ethyl-4-methyl-1,7-diaminoheptane, 2,2,5,5-tetramethyl-1,7-diaminoheptane, 3-isopropyl-1,7-diaminoheptane, 3-isooctyl-1,7-diaminoheptane, 1,3-dimethyl-1,8-diaminooctane, 1,4-dimethyl-1,8-diamino Octane, 2,4-dimethyl-1,8-diaminooctane, 3,4-dimethyl-1,8-diaminooctane, 4,5-dimethyl-1,8-diaminooctane, 2,2-dimethyl-1,8-diaminooctane, 3,3-dimethyl-1,8-diaminooctane, 4,4-dimethyl-1,8-diaminooctane, 3,3,5-trimethyl-1,8-diaminooctane, 2,4-diethyl-1,8-diaminooctane, and 5-methyl-1,9-diaminononane. Among these, preferred are units derived from a side-chain alkyldiamine having 1 to 2 side-chain alkyl groups with 1 to 2 carbon atoms and a main chain with 4 to 10 carbon atoms, and more preferred are units derived from 2-methyl-1,5-diaminopentane. Multiple types of these units may be contained in the polyamide resin (A).

[0057] Examples of the component unit (Ab3) derived from an alicyclic diamine having 4 to 20 carbon atoms include components derived from 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, 4,4'-diamino-3,3'-dimethyl Component units of dicyclohexylpropane, 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.

[0058] In this specification, the number of carbon atoms in the component unit derived from the alkylene diamine having a side chain alkyl group is the total number of carbon atoms of the main chain alkylene group and the number of carbon atoms of the side chain alkyl group, unless otherwise specified.

[0059] The polyamide resin (A) may further contain a small amount of component units derived from other diamines, such as component units derived from meta-xylylenediamine, in addition to the above-mentioned component units (Ab1), (Ab2), and (Ab3). The content of such component units derived from other diamines may be 50 mol% or less, preferably 40 mol% or less, relative to the total amount of the component units (Ab) derived from diamines.

[0060] From the perspective of improving the thermal stability of the composite or during molding or further improving the mechanical strength, at least a portion of the terminal groups of the polyamide resin (A) may be capped with an end-capping agent. For example, when the molecular ends are carboxyl groups, the end-capping agent is preferably a monoamine, and when the molecular ends are amino groups, the end-capping agent is preferably a monocarboxylic acid.

[0061] 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 2 to 30 carbon atoms such as acetic acid, propionic acid, butyric acid, valeric acid, caproic acid, octanoic acid, lauric acid, tridecanoic acid, myristic acid, palmitic acid, stearic acid, oleic acid, and linoleic acid; aromatic monocarboxylic acids such as benzoic acid, methylbenzoic acid, naphthoic acid, methylnaphthoic acid, and phenylacetic acid; and alicyclic monocarboxylic acids such as cyclohexanecarboxylic acid. Aromatic and alicyclic monocarboxylic acids may have substituents in the cyclic structure.

[0062] It should be noted that the dicarboxylic acid-derived component units (Aa) of the polyamide resin (A) may include component units derived from a biomass-derived dicarboxylic acid, and the diamine-derived component units (Ab) may include component units derived from a biomass-derived diamine. Furthermore, the polyamide resin (A) may be a biomass-derived polyamide resin (A) obtained by polymerizing a raw material component including a biomass-derived raw material.

[0063] [physical properties]

[0064] The melting point (Tm) of the polyamide resin (A) measured by a differential scanning calorimeter (DSC) (hereinafter, sometimes 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 the molded body in high temperature regions are not easily impaired. 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 tends to become 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 further preferably 300°C or higher and 340°C or lower.

[0065] The glass transition temperature (Tg) of the polyamide resin (A) is preferably 80° C. or higher and 150° C. or lower.

[0066] 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, and therefore it is easy to improve the heat resistance of the resin component. It should be noted that the upper limit of the heat of fusion (ΔH) of the polyamide resin (A) is not particularly limited, and from the viewpoint of not damaging the molding processability, it can be 130 J / g. 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.

[0067] 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).

[0068] Specifically, about 5 mg of polyamide resin (A) was sealed in an aluminum pan for measurement and heated from room temperature to 350°C at 10°C / min. In order to completely melt the resin, it was kept at 350°C for 3 minutes and then cooled to 30°C at 10°C / min. After standing at 30°C for 5 minutes, it was heated to 350°C for the second time at 10°C / min. The temperature (°C) of the endothermic peak in the second heating was set as the melting point (Tm) of the polyamide resin (A), and the inflection point corresponding to the glass transition was set as the glass transition temperature (Tg). The heat of fusion (ΔH) was calculated from the area of ​​the endothermic peak in the second heating process in accordance with JIS K7122.

[0069] 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 units (Aa) and the diamine-derived component units (Ab). For example, increasing the content of the terephthalic acid-derived component units (Aa1) or decreasing the content of the aromatic dicarboxylic acid-derived component units (Aa2) other than terephthalic acid, such as isophthalic acid, tends to increase the melting point (Tm), glass transition temperature (Tg), and heat of fusion (ΔH) of the polyamide resin (A).

[0070] The intrinsic viscosity [η] of the polyamide resin (A), measured at a temperature of 25°C in 96.5% sulfuric acid, is preferably 0.6 dl / g or greater and 1.5 dl / g or less. When the intrinsic viscosity [η] of the polyamide resin (A) is 0.6 dl / g or greater, the mechanical strength (toughness, etc.) of the molded article is readily improved, while 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 greater and 1.2 dl / g or less. The intrinsic viscosity [η] can be adjusted by, for example, the endcapping amount of the polyamide resin (A).

[0071] The intrinsic viscosity of the polyamide resin can be measured in accordance with JIS K6810-1977.

[0072] Specifically, 0.5 g of polyamide resin is dissolved in 50 ml of 96.5% sulfuric acid solution to prepare a sample solution. The flow time of this sample solution can be measured using an Ubbelohde viscometer at 25±0.05°C and the obtained value can be substituted into the following formula for calculation.

[0073] [η] = ηSP / [C (1 + 0.205ηSP)]

[0074] In the above formula, each algebra or variable represents the following.

[0075] [η]: intrinsic viscosity (dl / g)

[0076] ηSP: specific viscosity

[0077] C: sample concentration (g / dl)

[0078] ηSP is obtained by the following formula.

[0079] ηSP=(t-t0) / t0

[0080] t: The number of seconds for the sample solution to flow down (seconds)

[0081] t0: Number of seconds for blank sulfuric acid to flow (seconds)

[0082] The amount of the terminal amino group of 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 further preferably 20 mmol / kg or more and 100 mmol / kg or less. When the amount of the terminal amino group of polyamide resin (A) is 10 mmol / kg or more, it is easy to chemically interact with the glass fiber (C) processed by a surface treatment agent or a sizing agent, and it is easier to disperse the glass fiber (C). In addition, in the presence of the glass fiber (C) processed by a surface treatment agent or a sizing agent, it is easy to reduce the bending strength when adding a large amount of phosphorus compound (B). Therefore, the effect of suppressing the reduction of bending strength by making the addition amount of phosphorus compound (B) be certain or less is more significant. When the amount of the terminal amino group of polyamide resin (A) is 150 mmol / kg or less, the chemical interaction between polyamide resin (A) and glass fiber (C) is not easy to become excessive, and therefore the fluidity of the polyamide resin composition can be fully ensured.

[0083] The amount of terminal carboxylic acid groups in the polyamide resin (A) is preferably 60 mmol / kg to 220 mmol / kg, more preferably 80 mmol / kg to 200 mmol / kg, and even more preferably 100 mmol / kg to 180 mmol / kg.

[0084] The amount of terminal amino group and the amount of terminal carboxylic acid group can be measured by NMR.For example, polyamide resin (A) is dissolved in deuterated hexafluoroisopropanol (HFIP) and made into NMR determination sample, carry out NMR determination, obtain NMR spectrum.Can be according to the ratio of the peak area of ​​the methylene hydrogen adjacent to the terminal carboxylic acid structure in the spectrum obtained and the peak area of ​​the methylene hydrogen adjacent to amide structure, obtain terminal carboxylic acid structure amount (μeq / g) with the numerical value of polyamide resin (A) every mass parts.In addition, can be according to the peak area from the peak area of ​​terminal amine structure and the peak area of ​​the methylene hydrogen of the carboxylic acid component constituting amide structure, obtain terminal amine structure amount (μeq / g) with the numerical value of polyamide resin (A) every mass parts.The numerical value obtained can be converted into mmol / kg.

[0085] [Manufacturing method]

[0086] The polyamide resin (A) can be produced, for example, by polycondensing the dicarboxylic acid and the diamine in a homogeneous solution. Specifically, as described in International Publication No. 03 / 085029, 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, and then applying shear stress to the melt of the low-order condensate to cause polycondensation.

[0087] The above-mentioned end-capping 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 end-capping agent added.

[0088] The end-capping agent is added to the reaction system of the dicarboxylic acid and the diamine in an amount of preferably 0.07 mol or less, more preferably 0.05 mol or less, per 1 mol of the total amount of the dicarboxylic acid.

[0089] The content of the polyamide resin (A) in the polyamide resin composition is preferably 25 mass % or more and 80 mass % or less relative to the polyamide resin composition, more preferably 35 mass % or more and 70 mass % or less, further preferably 45 mass % or more and 65 mass % or less. The more the content of polyamide resin (A) is, the more the mechanical strength of the obtained molded article can be further improved. On the other hand, from the viewpoint of realizing the further improvement of characteristic by adding other components, the upper limit of the content of polyamide resin (A) can be set to above-mentioned scope.

[0090] 1-2. Phosphorus compound (B)

[0091] The phosphorus compound (B) can be added for the purpose of improving the tracking resistance of the polyamide resin composition. There is no particular limitation on the phosphorus compound (B) as long as it is a compound containing phosphorus element in the molecule, and it can 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 other components as needed after the polyamide resin (A) is synthesized by the above-mentioned polycondensation reaction. The phosphorus compound (B) preferably contains a compound having a -P(=O)- structure, and more preferably contains a compound having a -P(=O)-O- structure. In addition, the phosphorus compound (B) preferably contains a phosphinate compound, and more preferably contains a phosphinate metal salt compound. The mechanism by which the tracking resistance is improved by such a phosphorus compound (B) is not yet clear, but it is speculated as follows.

[0092] Tracking damage is believed to be caused by the fact that when a discharge occurs near the surface of a molded body of a polyamide resin composition, the polyamide resin (A) is heated and carbonized by the heat generated by the discharge, thereby reducing the resistance of the molded body surface. On the other hand, when the polyamide resin composition contains a phosphorus compound (B), a reaction in which the polyamide resin (A) is hydrolyzed by the phosphorus compound (B) may occur when a discharge occurs. Here, since the above-mentioned hydrolysis reaction is an endothermic reaction, the heating of the polyamide resin (A) by the heat generated by the discharge can be suppressed. As a result, it is believed that tracking damage can be suppressed. It should be noted that when the phosphorus compound (B) contains a compound having a -P(=O)-O- structure, the phosphorus compound (B) is hydrolyzed to become a compound having a -P(=O)-OH structure with high acidity, thereby further promoting the hydrolysis of the polyamide resin (A). Therefore, the heating of the polyamide resin (A) by the heat generated by the discharge can be further suppressed, and tracking damage can be further suppressed.

[0093] Furthermore, increasing the content of the phosphorus compound (B) is effective in further improving tracking resistance. However, it has been newly discovered that, in a polyamide resin composition comprising glass fibers (C) containing a surface treatment agent or a sizing agent, as described above, excessive phosphorus compound (B) content reduces the mechanical strength (particularly flexural strength) of the polyamide resin composition.

[0094] Usually, when utilizing glass fibre to enhance polyamide resin composition, in order to improve the dispersibility of glass fibre in polyamide resin composition or improve the glass fibre and the adhesiveness of polyamide resin at the interface between glass fibre and polyamide resin, mostly utilize surface treatment agent, sizing agent to process glass fibre.In the present embodiment, glass fibre (C) also comprises surface treatment agent, sizing agent, therefore when mixing of polyamide resin composition, the surface treatment agent, sizing agent that this glass fibre (C) has or the functional group formed by them on the surface of glass fibre (C) interact or react with the terminal amino group or the terminal carboxylic acid group of polyamide resin (A).Thus, glass fibre (C) improves relative to the dispersibility of polyamide resin (A), and the adhesiveness of glass fibre (C) and polyamide resin (A) improves.As a result, the reinforcing effect brought by glass fibre (C) can be obtained well, and the mechanical strength, the for example flexural strength of the molded body obtained by molding polyamide resin composition are improved.

[0095] Here, if the content of the phosphorus compound (B) is increased, the surface treatment agent, sizing agent or the functional group formed by them on the surface of the glass fiber (C) and the terminal amino group or terminal carboxylic acid group of the polyamide resin (A) are easily attacked or reacted by the phosphorus compound (B) and broken. This becomes significant when the phosphorus compound (B) contains a compound having a -P(=O)- structure or a compound having a -P(=O)-O- structure. As a result, the dispersibility of the glass fiber (C) relative to the polyamide resin (A) is reduced. Alternatively, the adhesion between the glass fiber (C) and the polyamide resin (A) is reduced. As a result, it is believed that the flexural strength of the molded body obtained by molding the polyamide resin composition is reduced.

[0096] In particular, when a high-melting-point polyamide is used as the polyamide resin (A), the polyamide resin composition is heated to a high temperature during melt kneading and molding during its production. When the polyamide resin composition reaches a high temperature, it is more susceptible to attack by the phosphorus compound (B), resulting in a more significant decrease in flexural strength.

[0097] Thus, in the present embodiment, the content of the phosphorus compound (B) in the entire polyamide resin composition is appropriately reduced. Specifically, the containing ratio of the phosphorus element (comprising the phosphorus element from the phosphorus compound (B)) of the polyamide resin composition is made to be more than 500 mass ppm and less than 10000 mass ppm relative to the total amount of the polyamide resin composition. When the containing ratio of the above-mentioned phosphorus element is less than 10000 mass ppm, the mechanical strength of the molded article can be well maintained, and the electrical tracking resistance can be fully improved. When the containing ratio of the above-mentioned phosphorus element is more than 500 mass ppm, the electrical tracking resistance can be fully improved. From the same viewpoint, the containing ratio of the above-mentioned phosphorus element in the polyamide resin composition is preferably set to more than 1000 mass ppm and less than 9000 mass ppm, more preferably set to more than 2000 mass ppm and less than 8000 mass ppm, further preferably set to more than 2200 mass ppm and less than 6200 mass ppm, particularly preferably set to more than 4000 mass ppm and less than 6200 mass ppm relative to the total amount of the polyamide resin composition.

[0098] The phosphorus content of the polyamide resin composition can be measured at a wavelength of 213.618 (nm) by high-frequency inductively coupled plasma (ICP) emission analysis using, for example, IRIS / IP manufactured by Thermo Jarrell Ash.

[0099] In the polyamide resin composition or the molded article obtained by molding the polyamide resin composition, the phosphorus compound (B) is preferably thermally bonded to the polyamide resin (A). In addition, in the polyamide resin composition or the 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, when the phosphorus compound (B) is thermally bonded or in direct contact with the polyamide resin (A), a reaction in which the polyamide resin (A) is hydrolyzed by the phosphorus compound (B) can be easily and efficiently performed when discharge occurs.

[0100] 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.

[0101] [Chemistry 2]

[0102]

[0103] In formula (I) and (II), R 1 and R 2 They are respectively C1~C6 alkyl or aryl.

[0104] R 3It is a C1-C10 alkylene group, a C6-C10 arylene group, a C6-C10 alkylarylene group or a C6-C10 arylalkylene group.

[0105] 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.

[0106] 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.

[0107] 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 methanedi(methylphosphinate). Calcium, magnesium methanedi(methylphosphinate), aluminum methanedi(methylphosphinate), zinc methanedi(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, zinc diphenylphosphinate. Preferred are calcium dimethylphosphinate, aluminum dimethylphosphinate, zinc dimethylphosphinate, calcium ethylmethylphosphinate, aluminum ethylmethylphosphinate, zinc ethylmethylphosphinate, calcium diethylphosphinate, aluminum diethylphosphinate, zinc diethylphosphinate; more preferred are aluminum diethylphosphinate. One of the main reasons for the occurrence of electric tracking damage can be cited as the carbonization of the polyamide resin composition. Therefore, if the aromatic ring concentration in the polyamide resin composition is high, there is a tendency for electric tracking damage to occur easily, but the phosphorus compound (B) does not contain aromatic rings, so that the aromatic rings in the polyamide resin composition can be increased without the phosphorus compound (B). In addition, when the phosphorus compound (B) has a hydroxyl group, it is easy for the phosphorus compound (B) to interact or react with the terminal amino group or terminal carboxylic acid group of the surface treatment agent, sizing agent or functional group formed on the surface of the glass fiber (C) and the polyamide resin (A) by the surface treatment agent, sizing agent or functional group formed on the surface of the glass fiber (C). Therefore, the phosphorus compound (B) preferably does not have a hydroxyl group. From the above viewpoint, the phosphorus compound (B) particularly preferably includes aluminum diethylphosphinate.

[0108] Representative examples of the phosphorus compound (B) include EXOLIT OP1230 and OP930 manufactured by Clariant Japan.

[0109] The average particle size (D50) of the phosphorus compound (B) is not particularly limited, for example, preferably 5 μm or more and 100 μm or less, more preferably 10 μm or more and 80 μm or less, further preferably 20 μm or more and 60 μm or less, 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, and therefore, the excessive attack of the interaction or reaction part between the polyamide resin (A) and the glass fiber (C) by the phosphorus compound (B) during melt mixing and molding when manufacturing the polyamide resin composition can be suppressed, and as a result, it is easier to suppress the reduction 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, so even if the addition amount of the phosphorus compound (B) is not excessively increased, it is easy to exert the effect of suppressing electric tracking damage. The average particle size of the phosphorus compound (B) can be measured by dynamic light scattering.

[0110] The content of the phosphorus compound (B) in polyamide resin composition also depends on the composition of polyamide resin composition, as long as the containing rate of phosphorus element becomes the scope of above-mentioned scope, for example, relative to the total amount of polyamide resin composition, preferably more than 0.5 mass % and less than 5 mass %, more preferably more than 0.75 mass % and below 4.5 mass %, further preferably more than 1 mass % and below 4 mass %, particularly preferably more than 2 mass % and below 4 mass %. The more the content of phosphorus compound (B) is, the more the electric tracking resistance of polyamide resin composition can be further improved. The less the content of phosphorus compound (B), the more the mechanical strength reduction of molded body can be reduced.

[0111] In addition, from the same viewpoint as above, the content of the phosphorus compound (B) in the polyamide resin composition is preferably 0.5 mass % or more and 10 mass % or less, more preferably 0.5 mass % or more and 8 mass % or less, further preferably 1 mass % or more and 7 mass % or less, and particularly preferably 2 mass % or more and 6 mass % or less, relative to the polyamide resin (A).

[0112] 1-3. Glass fiber (C)

[0113] The type of glass fiber (C) is not particularly limited as long as it is a glass fiber for the reinforcement of the resin, and can be chopped strands or milled fibers of shorter fiber lengths. In addition, the cross-sectional shape of the glass fiber can be circular or non-circular such as elliptical or oblong.

[0114] From the viewpoint of improving the moldability of the polyamide resin composition and improving the mechanical strength and heat resistance of the resulting molded article, the average fiber length of the glass fiber (C) can be, for example, 1 μm to 20 mm, preferably 5 μm to 10 mm. Furthermore, the aspect ratio of the glass fiber is, for example, 5 to 2000, preferably 30 to 600.

[0115] The average fiber length and average fiber diameter of the glass fiber (C) can be measured by the following method.

[0116] 1) A polyamide resin composition was dissolved in a hexafluoroisopropanol / chloroform solution (0.1 / 0.9 volume %), followed by filtration to collect the filtrate.

[0117] 2) The filtrate obtained in 1) above was dispersed in water, and the fiber length (Li) and fiber diameter (Di) of 300 random fibers were measured using an optical microscope (magnification: 50x). The number of fibers having a fiber length of Li was defined as qi, and the weight-average fiber length (Lw) was calculated based on the following formula, which was used as the average fiber length of the glass fibers.

[0118] Weight average length (Lw) = (Σqi × Li 2 ) / (Σqi×Li)

[0119] Similarly, the number of fibers having a fiber diameter of Di is defined as ri, and the weight average diameter (Dw) is calculated based on the following formula, which is used as the average fiber diameter of the glass fibers.

[0120] Weight average diameter (Dw)=(Σri×Di 2 ) / (Σri×Di)

[0121] The glass fiber (C) contains a surface treatment agent or a sizing agent.

[0122] The surface treatment agent or sizing agent may be any known surface treatment agent or sizing agent used for glass fibers blended into the polyamide resin composition. 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, carbamate compounds, carboxylic acid compounds, carbamate / maleic acid modified compounds, and carbamate / amine modified compounds.

[0123] The surface treatment agent or the sizing agent preferably has an acidic group. That is, the surface treatment agent or the sizing agent preferably comprises a compound having an acidic group. When the surface treatment agent or the sizing agent has an acidic group, it is easy to interact or react with the terminal amino group of the polyamide resin (A). Therefore, the dispersibility of the glass fiber (C) relative to 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 brought by the glass fiber (C) can be obtained more preferably, and the mechanical strength, such as bending strength, of the molded body obtained by molding the polyamide resin composition is further improved. In addition, when the surface treatment agent or the sizing agent has an acidic group, the interaction between the acidic group and the terminal amino group of the polyamide resin (A) is particularly easily hindered by the phosphorus compound (B). Therefore, the effect brought by appropriately reducing the content of the phosphorus compound (B) in the polyamide resin composition becomes more significant.

[0124] Examples of acidic groups include carboxyl groups, acid anhydride groups, carboxylate groups, and sulfonic acid groups. Of these, carboxyl groups, acid anhydride groups, and carboxylate groups are preferred, and carboxyl groups and acid anhydride groups are more preferred. The carboxylate group may be a functional group derived from a carboxylate.

[0125] Examples of the surface treatment agent having an acidic group include silane coupling agents containing an acid anhydride group, such as 3-trimethoxysilylpropylsuccinic anhydride.

[0126] Examples of the sizing agent 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 and an unsaturated monomer.

[0127] 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. Among them, acrylic acid, methacrylic acid, maleic acid, and maleic anhydride are preferred.

[0128] Examples of the unsaturated monomer include styrene, butadiene, acrylonitrile, vinyl acetate, methyl acrylate, ethyl acrylate, methyl methacrylate, ethyl methacrylate, methylstyrene, ethylene, propylene, butylene, isobutylene, and vinyl ether, etc. Among them, methyl acrylate and methyl methacrylate are preferred, and both methyl acrylate and methyl methacrylate are more preferred.

[0129] When the sizing agent comprises a copolymer of an unsaturated carboxylic acid or its anhydride and an unsaturated monomer, the ratio of the unsaturated carboxylic acid or its anhydride relative to the above-mentioned copolymer is preferably 20% by mass or more and 60% by mass or less. When the above-mentioned ratio is 20% by mass or more, the effect of improving the mechanical strength of the polyamide resin composition brought about by improving the chemical interaction between the acidic group (carboxyl group) and the polyamide resin (A) is significant. When the above-mentioned ratio is 60% by mass or less, the chemical interaction between the acidic group and the polyamide resin (A) is difficult to become excessive, and therefore the fluidity of the polyamide resin composition during molding is difficult to be further damaged.

[0130] The weight average molecular weight (Mw) of above-mentioned homopolymer or copolymer is preferably more than 3000 and below 60000.When the weight average molecular weight of above-mentioned homopolymer or copolymer is set to more than 3000, by increasing the molecular weight (chain length) of above-mentioned homopolymer or copolymer and making easy to bring about the mechanical strength of the raising polyamide resin composition of the molecular chain entanglement (improving physical interaction) of polyamide resin (A) further improves.On the other hand, by making the weight average molecular weight of above-mentioned homopolymer or copolymer be below 60000, the dispersibility of glass fiber (C) in polyamide resin (A) can be further improved.From the above viewpoint, the weight average molecular weight of above-mentioned homopolymer or copolymer is preferably more than 10000 and below 50000, more preferably more than 20000 and below 50000.It should be noted that the weight average molecular weight of above-mentioned homopolymer or copolymer utilizes gel permeation chromatography (GPC) to measure, the value calculated using polystyrene as standard substance.

[0131] The homopolymer or copolymer can be used in combination with other resins such as polyurethane resins and epoxy resins. Preferably, the homopolymer or copolymer is used in combination with a polyurethane resin. That is, the sizing agent preferably contains the homopolymer or copolymer and a polyurethane resin.

[0132] Specifically, the urethane bond sites (-NHCO-) ​​of the polyurethane resin have moderately good affinity for the terminal carboxyl groups of the polyamide resin (A), thereby facilitating interaction between the glass fiber (C) and the polyamide resin (A). Therefore, even when the phosphorus compound (B) is included, the affinity between the glass fiber (C) and the polyamide resin (A) is further enhanced, making it easier to disperse the glass fiber (C) in the polyamide resin (A).

[0133] Examples of the polyurethane resin include polyurethane resins synthesized from isocyanates such as meta-xylylenediisocyanate (XDI), 4,4′-methylenebis(cyclohexylisocyanate) (HMDI), and isophorone diisocyanate (IPDI), and polyester-based or polyether-based diols.

[0134] (Manufacturing Method)

[0135] Glass fibers containing a surface treatment agent or a sizing agent can be obtained, for example, by applying (coating) the surface treatment agent or the sizing agent to fiber strands using a known method such as a roller applicator during the glass fiber production process, followed by drying and reacting.

[0136] The amount of the surface treatment agent or sizing agent applied 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, relative to 100 parts by mass of the glass fiber (C), as measured by solid content. When the applied amount is 0.2 parts by mass or greater, the bundling properties of the glass fiber (C) are further improved. Furthermore, when the applied amount is 2 parts by mass or less, the thermal stability of the polyamide resin composition is further improved.

[0137] The content of the glass fibre (C) in polyamide resin composition is preferably 15 mass % or more and 70 mass % or less relative to the total amount of polyamide resin composition, more preferably 25 mass % or more and 60 mass % or less, further preferably 30 mass % or more and 50 mass % or less.The more the content of glass fibre (C) is, the more the mechanical strength of polyamide resin composition can be further improved.The less the content of glass fibre (C), the more the mechanical strength reduction of the formed body caused by the addition of phosphorus compound (B) can be reduced.

[0138] 1-4. Other ingredients

[0139] 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.

[0140] Examples of other components include colorants, crystal nucleating agents, lubricants, corrosion resistance improvers, anti-dripping agents, ion scavengers, elastomers (rubbers), antistatic agents, release agents, antioxidants (phenols, amines, sulfurs, and phosphorus), heat stabilizers (lactone compounds, vitamin E compounds, hydroquinones, copper halides, and iodine compounds), light stabilizers (benzotriazoles, triazines, benzophenones, benzoates, hindered amines, and oxanilides), other polymers (polyolefins, olefin copolymers such as ethylene-propylene copolymers and ethylene-1-butene copolymers, olefin copolymers such as propylene-1-butene copolymers, polystyrene, polyamide, polycarbonate, polyacetal, polysulfone, polyphenylene ether, fluororesins, silicone resins, and LCP), etc.

[0141] The colorant imparts the desired hue to the molded article. The colorant is not particularly limited and may be a pigment. Examples of pigments include inorganic pigments such as carbon black, aluminum oxide, 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.

[0142] 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.

[0143] Crystallization nucleating agents can improve the crystallinity of the molded body. Examples of crystallization nucleating agents include: metal salt compounds containing sodium 2,2-methylenebis(4,6-di-tert-butylphenyl) phosphate, aluminum tris(p-tert-butylbenzoate) and stearate; sorbitol compounds containing bis(p-methylbenzylidene)sorbitol and bis(4-ethylbenzylidene)sorbitol; and inorganic substances including talc, calcium carbonate and hydrotalcite. Among them, talc is preferred from the viewpoint of further improving the crystallinity of the molded body. These crystallization nucleating agents can be used alone or in combination of two or more.

[0144] The content of the crystallization nucleating agent is preferably 0.1% by mass to 5% by mass, more preferably 0.1% by mass to 3% by mass, relative to the total amount of the polyamide resin composition. When the content of the crystallization nucleating agent is within the above range, the crystallinity of the molded article can be further increased, and higher mechanical strength can be easily obtained.

[0145] The lubricant improves the injection fluidity of the polyamide resin composition and improves the appearance of the resulting molded article. The lubricant can be a fatty acid metal salt such as a hydroxycarboxylic acid metal salt or a higher fatty acid metal salt.

[0146] The hydroxycarboxylic acid constituting the metal salt of hydroxycarboxylic acid may be an aliphatic hydroxycarboxylic acid or an aromatic hydroxycarboxylic acid. Examples of aliphatic hydroxycarboxylic acids include aliphatic hydroxycarboxylic 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-hydroxytetracosanoic acid, α-hydroxyhexacosanoic acid, α-hydroxyoctacosanoic 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 hydroxycarboxylic acids include salicylic acid, m-hydroxybenzoic acid, p-hydroxybenzoic acid, gallic acid, mandelic acid, and tropic acid.

[0147] Examples of the metal constituting the hydroxycarboxylic acid metal salt include alkali metals such as lithium and alkaline earth metals such as magnesium, calcium and barium.

[0148] Among them, the hydroxycarboxylic acid metal salt is preferably a metal salt of 12-hydroxystearic acid, and more preferably magnesium 12-hydroxystearate and calcium 12-hydroxystearate.

[0149] Examples of the higher fatty acid constituting the higher fatty acid metal salt include higher fatty acids having 15 to 30 carbon atoms, such as stearic acid, oleic acid, behenic acid, behenic acid, and montanic acid.

[0150] Examples of the metal constituting the higher fatty acid metal salt include calcium, magnesium, barium, lithium, aluminum, zinc, sodium, potassium and the like.

[0151] Among them, preferred higher fatty acid metal salts are calcium stearate, magnesium stearate, barium stearate, calcium behenate, sodium montanate, calcium montanate, and the like.

[0152] The lubricant content 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 lubricant content is 0.01% by mass or more, the fluidity during molding is more easily improved, and the appearance of the resulting molded article is more easily improved. When the lubricant content is 1.3% by mass or less, gas generated by decomposition of the lubricant is less likely to be generated during molding, and the appearance of the product is more likely to be improved.

[0153] 1-5. Manufacturing Method

[0154] The polyamide resin composition can be produced by mixing the above-mentioned polyamide resin (A), phosphorus compound (B), glass fiber (C) and other components as needed using a known resin kneading method, such as a Henschel mixer, a V-type mixer, a ribbon mixer or a drum mixer, or by further melt-kneading the mixed components using a single-screw extruder, a multi-screw extruder, a kneader or a Banbury mixer, followed by granulation or pulverization.

[0155] 2. Application of polyamide resin composition

[0156] The polyamide resin composition of the present invention can be molded by a known molding method such as compression molding, injection molding, and extrusion molding to be used as various molded products.

[0157] The molded articles of the polyamide resin composition can be used in various applications. In particular, the polyamide resin composition has good mechanical strength and tracking resistance and is therefore preferably used in fields requiring these properties or in precision molding applications. Examples of such applications include various molded articles for electrical / electronic components such as automotive electrical components, connectors, switches, sockets, plugs, circuit breakers, electromagnetic switches, current interrupters, and LED reflective materials, as well as automotive parts.

[0158] Example

[0159] Hereinafter, the present invention will be described with reference to Examples, but the scope of the present invention is not limited by the Examples.

[0160] In the following experiments, the melting point (Tm), glass transition temperature (Tg), intrinsic viscosity, heat of fusion, and terminal amino group content of the polyamide resin were measured by the following methods.

[0161] (Melting point (Tm), glass transition temperature (Tg), heat of fusion (ΔH))

[0162] 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 model, manufactured by Seiko Instruments).

[0163] Specifically, about 5 mg of polyamide resin was sealed in an aluminum pan for measurement and heated from room temperature to 350°C at 10°C / min. In order to completely melt the resin, it was kept at 350°C for 3 minutes and then cooled to 30°C at 10°C / min. After standing at 30°C for 5 minutes, it was heated to 350°C for the second time at 10°C / min. The temperature (°C) of the endothermic peak in the 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 calculated from the area of ​​the endothermic peak in the second heating process in accordance with JIS K7122.

[0164] (Intrinsic viscosity [η])

[0165] The intrinsic viscosity [η] of the polyamide resin is calculated as follows: 0.5 g of the polyamide resin is dissolved in 50 ml of a 96.5% sulfuric acid solution, and the flow time of the resulting solution at 25°C ± 0.05°C is measured using an Ubbelohde viscometer. The intrinsic viscosity [η] is calculated based on the formula: [η] = ηSP / (C(1 + 0.205ηSP))".

[0166] [η]: intrinsic viscosity (dl / g)

[0167] ηSP: specific viscosity

[0168] C: sample concentration (g / dl)

[0169] t: The number of seconds for the sample solution to flow down (seconds)

[0170] t0: Number of seconds for blank sulfuric acid to flow (seconds)

[0171] ηSP=(t-t0) / t0

[0172] (Amount of terminal amino groups, amount of terminal carboxylic acid groups)

[0173] The amount of terminal amino groups and the amount of terminal carboxylic acid groups in the polyamide resin were measured by NMR.

[0174] 30 mg of a polyamide resin was dissolved in 0.5 mL of deuterated hexafluoroisopropanol (HFIP) to prepare a sample for NMR measurement.

[0175] NMR measurements were performed on the samples using an ECA-500 nuclear magnetic resonance apparatus (500 MHz-NMR) (manufactured by JEOL Ltd.). The ratio of the peak area of ​​the methylene hydrogen adjacent to the terminal carboxylic acid structure to the peak area of ​​the methylene hydrogen adjacent to the amide structure in the obtained spectrum was used to determine the terminal carboxylic acid structure content (μeq / g) per part by mass of the polyamide resin. For quantification of the terminal amine, the peak area derived from the terminal amine structure and the peak area of ​​the methylene hydrogen of the carboxylic acid component constituting the amide structure were used to determine the terminal amine structure content (μeq / g) per part by mass of the polyamide resin. The resulting value was then converted to mmol / kg.

[0176] 1. Material Preparation

[0177] 1-1. Polyamide resin (A)

[0178] Synthesis of polyamide resin (A1)

[0179] 2800 g (24.1 mol) of 1,6-hexanediamine, 2774 g (16.7 mol) of terephthalic acid, 1196 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 3 hours. At this point, the internal pressure of the autoclave was raised to 3.03 MPa. After continuing the reaction for 1 hour, the mixture was released to the atmosphere through a spray nozzle located at the bottom of the autoclave, and the lower condensate was removed. The lower condensate was then cooled to room temperature, pulverized using a pulverizer to a particle size of 1.5 mm or less, and dried at 110°C for 24 hours. The resulting lower condensate had a moisture content of 4100 ppm and an intrinsic viscosity [η] of 0.15 dl / g.

[0180] Next, the lower condensate was placed in a tray-type solid-phase polymerization apparatus. After nitrogen substitution, the temperature was raised to 180°C over approximately 1 hour and 30 minutes. The reaction was then allowed to proceed for 1 hour and 30 minutes, and the temperature was then lowered to room temperature. The resulting prepolymer had an intrinsic viscosity [η] of 0.20 dl / g.

[0181] The obtained prepolymer was then melt polymerized using 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 speed of 200 rpm, and a resin supply rate of 6 kg / h to obtain a polyamide resin (A1).

[0182] 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. Furthermore, the polyamide resin (A1) had a terminal amino group content of 20 mmol / kg and a terminal carboxyl group content of 140 mmol / kg.

[0183] 1-2. Phosphorus compound (B)

[0184] Phosphinate compound (EXOLIT OP1230 manufactured by Clariant Japan, phosphorus content: 23.8% by mass, aluminum diethylphosphinate, average particle size (D50): 10 to 50 μm)

[0185] 1-3. Glass fiber (C)

[0186] 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: a mixture of a polymer of an unsaturated vinyl monomer containing maleic acid and a polyurethane resin)

[0187] 1-4. Colorant (D)

[0188] A masterbatch containing 94% by mass of the polyamide resin (A1) and 6% by mass of the pigment was used as the resin.

[0189] 1-5. Crystallization nucleating agent (E)

[0190] Talc (fine talc, average particle size 6 μm)

[0191] 1-6. Lubricant (F)

[0192] Sodium montanate

[0193] 2. Preparation of polyamide resin composition

[0194] (Examples 1 to 4, Comparative Examples 1 to 3)

[0195] The above materials were mixed in a tumble mixer at the composition ratios shown in Table 1 (parts by mass) and melt-kneaded using a 30 mm dia. vented twin-screw extruder at a barrel temperature of 300-335°C. The kneaded mixture was then extruded into strands and cooled in a water tank. The strands were then drawn and cut using a pelletizer to obtain pelletized polyamide resin compositions.

[0196] The phosphorus content of the polyamide resin composition was measured at a wavelength of 213.618 (nm) by high-frequency inductively coupled plasma (ICP) emission spectrometry using IRIS / IP manufactured by Thermo Jarrell Ash.

[0197] 3. Evaluation

[0198] The obtained polyamide resin composition was evaluated according to the following criteria.

[0199] 3-1. Tracking resistance

[0200] The obtained polyamide resin composition was injection-molded under the following conditions to prepare a test piece of 120 mm×130 mm×3 mm.

[0201] Molding machine: Sumitomo Heavy Industries, Ltd., SE75EV-A

[0202] Molding machine barrel temperature: 335℃

[0203] Mold temperature: 160℃

[0204] The tracking resistance of the test piece prepared was evaluated according to IEC60112. Specifically, a YST-112 tracking tester made by YAMAYO tester was used. At 23±2°C and 45-50% RH, within the range of measuring voltage of 100-1000V, liquid A (0.1% ammonium chloride aqueous solution) was added as the test liquid every 30 seconds, and 50 drops were added to confirm whether the test piece had tracking. This operation was repeated by changing the voltage to find the maximum voltage (CTI) at which the test piece did not have tracking and was not destroyed at 50 drops. If no tracking occurs when 100 drops are added at a voltage 25V lower than the maximum voltage, it is judged to be qualified. The higher the maximum voltage, the better the tracking resistance. Moreover, if the maximum voltage is 550V or more, it is judged to be good.

[0205] 3-2. Flow length

[0206] The obtained polyamide resin composition was injected into a rod flow mold with 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. It should be noted that a longer flow length indicates better injection fluidity.

[0207] Molding machine: EC75N-2A, manufactured by Toshiba Machine Co., Ltd.

[0208] Injection setting pressure: 2000kg / cm 2

[0209] Molding machine barrel temperature: 335℃

[0210] Mold temperature: 160℃

[0211] 3-3. Flow Length Maintenance Rate Before and After Phosphorus Compound Addition

[0212] The flow length of the polyamide resin composition containing the phosphorus compound (B) was compared with the flow length of a polyamide resin composition containing the same amount of additives except that the phosphorus compound (B) was not contained, and the flow length maintenance rate before and after the addition of the phosphorus compound (B) was calculated.

[0213] 3-4. Bending strength

[0214] The obtained polyamide resin composition was injection-molded under the following conditions to prepare a test piece having a thickness of 3.2 mm.

[0215] Molding machine: Sumitomo Heavy Industries, Ltd., SE75EV-A

[0216] Molding machine barrel temperature: 335℃

[0217] Mold temperature: 160℃

[0218] The prepared test pieces were left to stand in a nitrogen atmosphere at 23°C for 24 hours. Subsequently, a bending test was conducted at 23°C and a relative humidity of 50% using a flexural testing machine (AB5 manufactured by NTESCO) with a span of 51 mm and a bending speed of 12.7 mm / min to measure the flexural strength.

[0219] 3-5. Retention rate of flexural strength before and after addition of phosphorus compound

[0220] 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 except that the phosphorus compound (B) was not contained, and the flexural strength retention rate before and after the addition of the phosphorus compound (B) was calculated.

[0221] The composition, flow length and its maintenance rate, flexural strength and its maintenance rate of the prepared polyamide resin composition are shown in Table 1. In addition, a graph obtained by plotting the obtained results is shown in Figure 1 . Figure 1The horizontal axis of the graph represents the phosphorus content (mass ppm) 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 no tracking failure occurs.

[0222] [Table 1]

[0223]

[0224] As can be seen from Table 1, the polyamide resin composition of Comparative Example 1, which does not contain a phosphorus compound (B), has 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) such that the phosphorus content in the polyamide resin composition exceeds 10,000 ppm by mass, have high tracking resistance but low flexural strength retention.

[0225] In contrast, it was found that the polyamide resin compositions of Examples 1 to 4 containing a small amount of the phosphorus compound (B) such that the phosphorus content was 10,000 ppm by mass or less exhibited high tracking resistance while maintaining high flexural strength.

[0226] By plotting these results Figure 1 It can be seen that the phosphorus content is limited to around 8000 mass ppm. If the phosphorus content increases above this limit, the bending strength decreases sharply. In contrast, if the phosphorus content is 8000 mass ppm or less, the decrease in bending strength is significantly less (CTI is maintained at 550V or above).

[0227] This shows that by including a small amount of the phosphorus compound (B) so that the phosphorus content is 10,000 ppm by mass or less, more preferably so that the phosphorus content is 8,000 ppm by mass or less, the flexural strength of the polyamide resin composition can be well maintained and the tracking resistance can be improved.

[0228] This application claims the benefit of priority based on Japanese Patent Application No. 2023-16026, filed on February 6, 2023. The entire contents of the specification and drawings of that application are incorporated herein by reference.

[0229] Industrial Application Possibilities

[0230] The polyamide resin composition of the present invention can provide a polyamide resin composition that maintains good mechanical strength and has high tracking resistance. Therefore, the present invention is expected to expand the application possibilities of polyamide resins in various applications and contribute to the further popularization of polyamide resins.

Claims

1. A polyamide resin composition comprising: 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); and glass fibers (C) containing a surface treatment agent or a sizing agent. The polyamide resin composition has a phosphorus content of 500 ppm by mass or more and 10,000 ppm by mass or less relative to the polyamide resin composition.

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

3. The polyamide resin composition according to claim 2, wherein The acidic group is a carboxyl group, anhydride group or carboxylate group.

4. The polyamide resin composition according to claim 2 or 3, wherein The surface treatment agent or sizing agent includes a compound having an acidic group and a polyurethane resin.

5. The polyamide resin composition according to any one of claims 1 to 4, wherein The phosphorus compound (B) includes a phosphinate compound.

6. The polyamide resin composition according to claim 5, wherein The phosphinate compound is one or more selected from the group consisting of compounds represented by formula (I) or formula (II), or condensates thereof, [Chemistry 1] Where R 1 and R 2 are C1~C6 alkyl or aryl, R 3 is C1-C10 alkylene, C6-C10 arylene, C6-C10 alkylarylene or C6-C10 arylalkylene, 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 polyamide resin composition according to any one of claims 1 to 6, wherein The phosphorus compound (B) comprises aluminum diethylphosphinate.

8. The polyamide resin composition according to any one of claims 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 claims 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, The dicarboxylic acid-derived component units (Aa) include component units derived from aromatic dicarboxylic acid.

10. The polyamide resin composition according to any one of claims 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, The dicarboxylic acid-derived component units (Aa) include terephthalic acid-derived component units and isophthalic acid-derived component units.

11. The polyamide resin composition according to any one of claims 1 to 10, wherein The content of the phosphorus compound (B) is 0.5% by mass or more and less than 5% by mass based on the polyamide resin composition.

12. The polyamide resin composition according to any one of claims 1 to 11, wherein The content of the glass fiber (C) is 25% by mass or more and 60% by mass or less based on the polyamide resin composition. 13 . A molded article comprising the polyamide resin composition according to claim 1 .

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