Polyamide resin composition and metal resin composite

Abstract

The present invention provides: a polyamide resin composition for insert molding, which is excellent in terms of tracking resistance, flame retardancy, and heat shock resistance; and a metal resin composite which uses this polyamide resin composition. The present invention relates to a polyamide resin composition for insert molding. This polyamide resin composition contains: a polyamide resin (A1) which has a melting point of 280°C or higher as measured by a differential scanning calorimeter (DSC); a polyamide resin (A2) which has an amount of melting heat (ΔH) of 0 J / g to 5 J / g inclusive; a halogen-based flame retardant (B); a heat-absorbing filler (C); a fibrous reinforcing material (D) which has an aspect ratio of a cross-section of 1.5 or more; and a polyolefin resin (E) which is modified with an unsaturated carboxylic acid or a derivative thereof. The content of the polyolefin resin (B) is 2 mass% or more relative to the total mass of the polyamide resin composition.

Description

Polyamide resin composition and metal-resin composite

[0001] The present invention relates to a polyamide resin composition and a metal-resin composite.

[0002] Polyamide resin compositions have been known as molding materials. Polyamide resin compositions are widely used as materials for various parts, such as automotive parts and electrical and electronic parts, and are known to have excellent mechanical strength in molded articles. In particular, semi-aromatic polyamide resins are known to have high crystallinity and to have even better mechanical strength in molded articles.

[0003] For example, Patent Document 1 discloses a mobile phone housing made of a polyamide resin composition containing a semi-aromatic polyamide resin and a specific amount of glass fiber and glass flakes. Patent Document 1 states that the polyamide resin composition enables the housing to achieve good rigidity and impact resistance and low warpage after molding.

[0004]

[0003] Incidentally, polyamide resin compositions are sometimes used to form metal-resin composites in which a resin member molded from the polyamide resin composition is combined with a metal member. When such metal-resin composites are used in automotive parts (e.g., bus bars) and electrical / electronic parts, tracking failure may occur. Therefore, when using polyamide resin compositions for these applications, it is necessary to improve the tracking resistance of the resin members.

[0005] For example, Patent Document 2 discloses a flame-retardant resin composition comprising a polyamide resin, a halogen-based flame retardant (such as brominated polystyrene), an organic phosphinic acid or its salt, and a flame-retardant assistant. According to Patent Document 2, the flame-retardant resin composition is said to have improved flame retardancy and tracking resistance.

[0006] JP 2010-510374 A

[0007] However, since metal-resin composites using polyamide resin compositions are used, for example, in automobile parts, there is a demand for polyamide resin compositions that can withstand thermal shocks (high heat shock resistance) that occur when the environmental temperature changes from low to high. However, the polyamide resin composition described in Patent Document 2 was unable to improve heat shock resistance.

[0008] An object of the present invention is to provide a polyamide resin composition for insert molding, which is excellent in all of tracking resistance, flame retardancy, and heat shock resistance, and a metal-resin composite using the same.

[0009] In order to solve the above problems, one aspect of the present invention relates to polyamide resin compositions as set forth in the following [1] to [8]. [1] A polyamide resin composition for insert molding, comprising: a polyamide resin (A1) having a melting point of 280°C or higher as measured by a differential scanning calorimeter (DSC), a halogenated flame retardant (B), an endothermic filler (C), a fibrous reinforcing material (D) having a cross-sectional aspect ratio of 1.5 or higher, and a polyolefin resin (E) modified with an unsaturated carboxylic acid or a derivative thereof, wherein the content of the polyolefin resin (B) is 2% by mass or more based on the total mass of the polyamide resin composition. [2] The polyamide resin composition according to [1], further comprising a polyamide resin (A2) having a heat of fusion (ΔH) of 0 J / g or more and 5 J / g or less as measured by a differential scanning calorimeter (DSC). [3] The polyamide resin composition according to [1] or [2], wherein the content of the halogenated flame retardant (B) is 30% by mass or more and 40% by mass or less, based on the total mass of the thermoplastic resin and the halogenated flame retardant (B) contained in the polyamide resin composition. [4] The polyamide resin composition according to any one of [1] to [3], wherein the content of the endothermic filler (C) is 1% by mass or more and 10% by mass or less, based on the total mass of the polyamide resin composition. [5] The polyamide resin composition according to [4], wherein the content of the endothermic filler (C) is 3.5% by mass or more and 10% by mass or less, based on the total mass of the polyamide resin composition. [6] The polyamide resin composition according to any one of [1] to [5], wherein the endothermic filler (C) is zinc borate. [7] The polyamide resin composition according to any one of [1] to [6], wherein the content of the fibrous reinforcing material (D) is 35% by mass or more, based on the total mass of the polyamide resin composition. [8] The polyamide resin composition according to any one of [1] to [7], wherein the aspect ratio of the cross section of the fibrous reinforcing material (D) is 3.0 or more.

[0010] Another aspect of the present invention for solving the above problems relates to a metal-resin composite according to the following item [9]: [9] A metal-resin composite comprising: a metal member; and a resin member comprising the polyamide resin composition according to any one of items [1] to [8], composited with the metal member.

[0011] According to the present invention, it is possible to provide a polyamide resin composition for insert molding that is excellent in all of tracking resistance, flame retardancy, and heat shock resistance, and a metal-resin composite using the same.

[0012] Fig. 1 is a schematic diagram showing an exemplary form of a metal-resin composite as a busbar unit. Fig. 2 is a structural diagram showing an exemplary configuration of a moving body (vehicle) having a busbar unit. Fig. 3A is a perspective view showing the shape of an insert test piece prepared for evaluating heat shock resistance in the examples, Fig. 3B is a plan view of the insert test piece, and Fig. 3C is a cross-sectional view of the insert test piece taken along line A-A' shown in Fig. 3B.

[0013] Hereinafter, embodiments of the present invention will be described in detail, but the present invention is not limited to the following embodiments.

[0014] 1. Polyamide Resin Composition The polyamide resin composition according to this embodiment is a polyamide resin composition for insert molding, and includes a polyamide resin (A1) having a melting point of 280°C or higher as measured by differential scanning calorimetry (DSC), a halogen-based flame retardant (B), an endothermic filler (C), a fibrous reinforcing material (D) having a cross-sectional aspect ratio of 1.5 or higher, and a polyolefin resin (E) modified with an unsaturated carboxylic acid or a derivative thereof. The content of the polyolefin resin (E) is 2.0% by mass or more based on the total mass of the polyamide resin composition.

[0015] As described above, there is a demand for a polyamide resin composition having high heat shock resistance. According to the findings of the present inventors, it is believed that a metal-resin composite obtained by combining a polyamide resin composition containing a polyamide resin with a metal member is prone to cracking in the resin member contained in the metal-resin composite when the environmental temperature is changed to a lower temperature, and therefore the heat shock resistance is reduced.

[0016] When the environmental temperature changes from high to low, the resin member shrinks more due to the crystallization of the polyamide resin. When the resin member shrinks, the resin member shrinks more than the metal member because of the large difference in the linear expansion coefficient between the resin member and the metal member. At this time, stress related to the shrinkage of the resin member is thought to be generated at the interface between the resin member and the metal member. For this reason, it is thought that in a metal-resin composite, the resin member is particularly prone to cracking when the temperature changes from high to low.

[0017] In response to this, the present inventors have conducted research and found that the heat shock resistance can be improved by using a fibrous reinforcing material (D) having a cross-sectional aspect ratio of 1.5 or more and a polyolefin resin (E) modified with an unsaturated carboxylic acid or a derivative thereof.

[0018] When molding, the polyamide resin composition is poured into a mold in a molten state. It is believed that the fibrous reinforcing material is arranged so that the length direction of the fibers is parallel to the flow direction of the polyamide resin composition. Therefore, it is believed that the difference in linear expansion coefficient between the resin member and the metal member can be reduced, particularly in the flow direction. In this case, a fibrous reinforcing material (D) having a cross-sectional aspect ratio of 1.5 or more has a longer length in the direction perpendicular to the flow direction than a fibrous reinforcing material having an aspect ratio of less than 1.5, and therefore it is believed that the difference in linear expansion coefficient between the resin member and the metal member can also be reduced in the perpendicular direction. This reduces the difference in linear expansion coefficient between the resin member and the metal member in both the flow direction and the perpendicular direction, making it less likely for cracks to occur in the resin member.

[0019] According to the findings of the present inventors, cracking of resin members can be sufficiently suppressed by adding a fibrous reinforcing material (D) having a cross-sectional aspect ratio of 1.5 or more to a polyamide resin composition containing the polyolefin resin (E). The carboxyl groups of the polyolefin resin (E) modified with an unsaturated carboxylic acid or its derivative easily react with the amide groups of the polyamide resin (A1) to form bonds, which makes it easy to increase the molecular weight of the entire resin. This tends to increase the melt viscosity of the polyamide resin composition during kneading, making it easy to disperse the fibrous reinforcing material (D) in the polyamide resin composition. As a result, it is believed that the effect of the fibrous reinforcing material in suppressing cracking of resin members is fully exerted.

[0020] Furthermore, it is believed that the polyolefin resin (E) can reduce the elastic modulus of the polyamide resin composition even at low temperatures, thereby imparting flexibility to the resin member, thereby alleviating the stress generated by the contraction of the resin member when the temperature is changed from high to low, thereby suppressing the occurrence of cracks.

[0021] For these reasons, the polyamide resin composition of the present embodiment can have improved heat shock resistance.

[0022] Furthermore, the polyamide resin composition of the present embodiment can also improve tracking resistance and flame retardancy.

[0023] When a resin member containing a polyamide resin composition is used as an insulating member for insulating a conductive member, a voltage is applied to the resin member containing the polyamide resin composition. It is known that if a voltage is applied to the surface of a resin member containing a polyamide resin composition with traces of dirt and moisture attached thereto, tracking breakdown can occur. Specifically, the dirt and moisture act as electrical pathways, causing leakage current to flow between the electrodes, resulting in Joule heat. This Joule heat evaporates the moisture, forming a dry area (dry zone). Because the dry zone has high insulation resistance, applying a high voltage across the dry zone generates scintillation discharge. This supplies thermal energy to the surface of the resin member, causing carbonization and precipitation of carbides on the surface of the resin member. Repeated discharges then cause the carbides precipitated on the surface of the molded body to grow into carbonized areas, which then bridge the electrodes, resulting in tracking breakdown.

[0024] In contrast, the polyamide resin composition containing the endothermic filler (C) can improve the tracking resistance of the resin part. When the endothermic filler (C) is contained in the polyamide resin composition, it is thought that the endothermic filler can absorb most of the thermal energy supplied to the surface of the molded article when the scintillation discharge occurs. Since the thermal energy absorbed by the endothermic filler is consumed in the decomposition reaction of the endothermic filler, the amount of thermal energy supplied to the surface of the molded article can be reduced, and carbonization deterioration of the surface of the molded article can be suppressed. As a result, tracking failure is suppressed and tracking resistance is improved.

[0025] Furthermore, by including a fibrous reinforcing material (D) in the polyamide resin composition, the tracking resistance of the resin member can be further improved. When the fibrous reinforcing material (D) is included in the polyamide resin composition, the surface smoothness of the resin member obtained by molding the polyamide resin composition tends to be increased, and the unevenness on the surface of the resin member tends to be reduced. This is thought to prevent the scintillation discharge that occurs when a voltage is applied to the resin member from concentrating on the convex parts, and to further suppress the precipitation of carbides. Furthermore, it is thought that reducing the unevenness on the surface of the resin member can increase the contact angle of water on the surface of the resin member. This is thought to make it easier for water to form droplets when it adheres to the surface of the resin member, thereby suppressing the generation of leakage current between electrodes. As a result, the tracking resistance can be further improved.

[0026] Furthermore, the polyamide resin composition contains a halogen-based flame retardant (B), which imparts flame retardancy to the polyamide resin composition.

[0027] 1-1. Polyamide resin (A1) The polyamide resin (A1) is a polyamide resin having a melting point of 280° C. or higher as measured by a differential scanning calorimeter (DSC). The polyamide resin (A1) forms crystals in a molded article, and can increase the mechanical strength (such as tensile strength) of the molded article.

[0028] The polyamide resin (A1) is, for example, a polyamide resin containing a component unit (A1a) derived from a dicarboxylic acid and a component unit (A1b) derived from a diamine. Hereinafter, the polyamide resin containing the component unit (A1a) derived from a dicarboxylic acid and the component unit (A1b) derived from a diamine will be described.

[0029] (Component Units (A1a) Derived from Dicarboxylic Acid) The component units (A1a) derived from a dicarboxylic acid preferably include component units derived from an aromatic dicarboxylic acid, and more preferably include component units derived from terephthalic acid.

[0030] The content of the component units derived from terephthalic acid is preferably 20 mol% to 95 mol%, more preferably 30 mol% to 90 mol%, even more preferably 40 mol% to 85 mol%, and even more preferably 40 mol% to 65 mol%, based on the total number of moles of the component units (A1a) derived from dicarboxylic acids. When the content is 20 mol% or more, the melting point of the polyamide resin (A1) increases, and the heat resistance of the resin member is improved.

[0031] The dicarboxylic acid-derived unit (A1a) may contain a dicarboxylic acid-derived unit. Examples of the dicarboxylic acid include aliphatic dicarboxylic acids, alicyclic dicarboxylic acids, and aromatic dicarboxylic acids other than terephthalic acid. Of these, aliphatic dicarboxylic acids are preferred.

[0032] Examples of the aliphatic dicarboxylic acid include aliphatic dicarboxylic acids having from 4 to 20 carbon atoms. The number of carbon atoms is preferably from 6 to 12. Examples of such aliphatic dicarboxylic acids include adipic acid, azelaic acid, and sebacic acid. Among these, adipic acid and sebacic acid are preferred, and adipic acid is more preferred.

[0033] The content of the component units derived from the aliphatic dicarboxylic acid is preferably 0 mol % or more and 60 mol % or less, and more preferably 0 mol % or more and 45 mol % or less, relative to the total number of moles of the component units (A1a) derived from the dicarboxylic acid.

[0034] Examples of the alicyclic dicarboxylic acid include cyclohexanedicarboxylic acid and its esters.

[0035] Examples of aromatic dicarboxylic acids other than terephthalic acid include isophthalic acid, 2-methylterephthalic acid, and naphthalenedicarboxylic acid.

[0036] The content of the component units derived from an alicyclic dicarboxylic acid and an aromatic dicarboxylic acid other than terephthalic acid is preferably from 20 mol % to 80 mol % and more preferably from 25 mol % to 75 mol % relative to the total number of moles of the component units (A1a) derived from dicarboxylic acids.

[0037] (Diamine-Derived Component Unit (A1b)) The diamine-derived component unit (A1b) includes, for example, a component unit derived from an aliphatic diamine having from 4 to 15 carbon atoms, a component unit derived from an alicyclic diamine having from 4 to 20 carbon atoms, and a component unit derived from an aromatic diamine.

[0038] The number of carbon atoms in the aliphatic diamine is preferably 4 or more and 12 or less, and more preferably 6 or more and 12 or less. Examples of the aliphatic diamine include linear alkylenediamines and branched alkylenediamines.

[0039] Examples of the linear alkylenediamine include 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, 1,6-diaminohexane, 1,9-nonanediamine, and 1,10-diaminodecane are preferred, and 1,6-diaminohexane is more preferred. Only one type of linear alkylenediamine may be contained, or two or more types may be contained.

[0040] Examples of the branched alkylenediamine include 2,2-dimethyldiaminopropane, 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, 2-methyl-1,8-diaminooctane, 1,3-dimethyl-1,8-diaminooctane, 1,4-dimethyl-1,8-diaminooctane, 2, These include 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. Of these, 2-methyl-1,5-diaminopentane is preferred.

[0041] The content of the component units derived from the aliphatic diamine is preferably 30 mol % or more and 100 mol % or less, and more preferably 70 mol % or more and 100 mol % or less, based on the total number of moles of the component units (A1b) derived from the diamine.

[0042] Examples of the alicyclic diamine having 4 to 20 carbon atoms include 1,4-diaminocyclohexane, 1,3-diaminocyclohexane, 1,3-bis(aminomethyl)cyclohexane, 2,5-bisaminomethylnorbornane, and 2,6-bisaminomethylnorbornane, etc. Examples of the aromatic diamine include metaxylylenediamine, etc.

[0043] The constituent units of the polyamide resin (A1) and their ratios can be calculated from the ratios charged when the polyamide resin (A1) is prepared, or can be measured by NMR.

[0044] １ In the case of H-NMR measurement, for example, a nuclear magnetic resonance apparatus (ECX400 model manufactured by JEOL Ltd.) is used, the solvent is deuterated orthodichlorobenzene, the sample concentration is 20 mg / 0.6 mL, the measurement temperature is 120° C., and the observation nucleus is １ The conditions were H (400 MHz), sequence was a single pulse, pulse width was 5.12 μsec (45° pulse), repetition time was 7.0 sec, and the number of accumulations was 500 or more. The reference chemical shift was set to 0 ppm for hydrogen in tetramethylsilane, but similar results could also be obtained by setting the peak derived from residual hydrogen in deuterated orthodichlorobenzene at 7.10 ppm as the reference value for the chemical shift. １ Peaks such as H can be assigned by conventional methods.

[0045] １３ In the case of C-NMR measurement, for example, a nuclear magnetic resonance apparatus (ECP500 type manufactured by JEOL Ltd.) is used as the measurement apparatus, a mixed solvent of ortho-dichlorobenzene / heavy benzene (80 / 20% by volume) is used as the solvent, the measurement temperature is 120°C, and the observation nucleus is １３ The conditions were: C (125 MHz), single pulse proton decoupling, 45° pulse, repetition time 5.5 seconds, number of integrations 10,000 or more, and chemical shift reference value 27.50 ppm. Assignment of various signals was performed based on standard methods, and quantification could be performed based on the integrated value of signal intensity.

[0046] ​​The dicarboxylic acid-derived component units of the polyamide resin (A1) may include component units derived from a biomass-derived dicarboxylic acid, and the diamine-derived component units may include component units derived from a biomass-derived diamine. The polyamide resin (A1) may also be a biomass-derived polyamide resin (A1) obtained by polymerizing raw materials including a biomass-derived raw material.

[0047] Specific examples of the polyamide resin (A1) include polyamide 6T6I, polyamide 6T66, polyamide 6TDT, polyamide 6T6I66, polyamide 9T, polyamide 10T, and the like.

[0048] The polyamide resin (A1) can be produced by the same method as that for known polyamide resins, for example, by polycondensing a dicarboxylic acid and a diamine in a homogeneous solution. Specifically, the polyamide resin (A1) can be produced by heating a dicarboxylic acid and a 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 the melt of the low-order condensate to polycondense it.

[0049] The content of polyamide resin (A1) is preferably 15% by mass or more and 50% by mass or less, preferably 18% by mass or more and 45% by mass or less, and more preferably 20% by mass or more and 35% by mass or less, relative to the total mass of the polyamide resin composition. When the content is 15% by mass or more, the mechanical strength of the polyamide resin composition can be increased. When the content is 50% by mass or less, other components such as modified polyolefin resins described below can be sufficiently contained in the polyamide resin composition. It is preferable that polyamide resin (A1) be contained in the greatest amount among the thermoplastic resin components (excluding the halogen-based flame retardant (B)) contained in the polyamide resin composition, and more preferably be contained in the greatest amount among the thermoplastic resin components (excluding the halogen-based flame retardant (B)) and the halogen-based flame retardant (B).

[0050] (Physical Properties) From the viewpoint of further increasing the mechanical strength of a molded article, the melting point of the polyamide resin (A1) is 280° C. or higher, preferably 290° C. or higher, and more preferably 300° C. or higher. Furthermore, from the viewpoint of suppressing decomposition of the amide bond of the polyamide resin (A1), the melting point of the polyamide resin (A1) is preferably 340° C. or lower, and more preferably 330° C. or lower.

[0051] The melting point of the polyamide resin (A1) can be adjusted to the above range by adjusting the composition of the polyamide resin (A1). For example, the melting point can be increased by increasing the content of component units derived from terephthalic acid, which will be described later.

[0052] Furthermore, the polyamide resin (A1) preferably has a glass transition temperature (Tg) measured by differential scanning calorimetry (DSC) of more than 70°C and not more than 145°C, more preferably 75°C or more and not more than 145°C, and even more preferably 80°C or more and not more than 145°C. If the glass transition temperature (Tg) is more than 70°C, the temperature at which molecular mobility becomes active in a high-temperature environment becomes higher, thereby suppressing molecular mobility and further improving the heat resistance of the polyamide resin composition and molded article. If the glass transition temperature (Tg) is 145°C or less, the fluidity of the resin composition can be easily maintained without excessively increasing the mold temperature during molding, thereby improving molding processability.

[0053] The heat of fusion (ΔH) of the polyamide resin (A1) measured by differential scanning calorimetry (DSC) is preferably greater than 5 J / g. The heat of fusion is an index of the crystallinity of a resin, and the greater the heat of fusion, the higher the crystallinity. When the heat of fusion (ΔH) of the polyamide resin (A1) exceeds 5 J / g, the crystallinity is increased, and the mechanical strength (tensile strength, bending strength, etc.) of the resulting molded article can be increased.

[0054] The melting point and heat of fusion (ΔH) of the polyamide resin (A1) can be measured using a differential scanning calorimeter (DSC220C, manufactured by Seiko Instruments Inc.).

[0055] Specifically, approximately 5 mg of polyamide resin (A1) 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 (A1), 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 melting during the first heating process in accordance with JIS K7122.

[0056] The intrinsic viscosity [η] of the polyamide resin (A1), measured in 96.5% sulfuric acid at 25°C, is preferably 0.60 dl / g or more and 1.50 dl / g or less, more preferably 0.70 dl / g or more and 1.20 dl / g or less, and particularly preferably 0.75 dl / g or more and 1.10 dl / g or less. When the intrinsic viscosity [η] of the polyamide resin (A1) is 0.60 dl / g or more, the mechanical strength (e.g., bending strength) of the molded product is easily increased, and when it is 1.50 dl / g or less, the fluidity of the resin composition during molding is less likely to be impaired. The intrinsic viscosity [η] can be adjusted by adjusting the molar ratio of the dicarboxylic acid-derived component unit (A1a) and the diamine-derived component unit (A1b). Specifically, the closer the molar ratio of the carboxylic acid-derived component unit (A1a) and the diamine-derived component unit (A1b) is to 1:1, the higher the intrinsic viscosity can be. It can also be adjusted by the amount of end-capping of the polyamide resin (A1).

[0057] The intrinsic viscosity [η] of polyamide resin (A1) can be measured as follows. 0.5 g of polyamide resin (A1) is dissolved in 50 ml of 96.5% sulfuric acid solution to prepare a sample solution. The flow time of the obtained solution at 25°C ± 0.05°C is measured using an Ubbelohde viscometer and calculated based on the following formula: [η] = ηSP / (C*(1 + 0.205ηSP)) [η]: intrinsic viscosity (dl / g) ηSP: specific viscosity C: sample concentration (g / dl) t: flow time of the sample solution (seconds) t ０: Number of seconds for blank sulfuric acid to flow (seconds) ηSP = (t - t ０ ) / t ０

[0058] The amount of terminal amino groups in the polyamide resin (A1) is preferably 10 mmol / kg or more and 200 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 150 mmol / kg or less. When the amount of terminal amino groups in the polyamide resin (A1) is 10 mmol / kg or more, the polyamide resin (A1) is likely to chemically interact with the surface treatment agent or sizing agent of the fibrous reinforcing material (D) or the scaly or plate-like inorganic particles (E), making it easier to disperse the fibrous reinforcing material (D) or the scaly or plate-like inorganic particles (E). When the amount of terminal amino groups in the polyamide resin (A1) is 200 mmol / kg or less, the chemical interaction between the polyamide resin (A1) and the fibrous reinforcing material (D) or the scaly or plate-like inorganic particles (E) is unlikely to be excessive, thereby ensuring sufficient fluidity of the polyamide resin composition.

[0059] The amount of terminal carboxylic acid groups in the polyamide resin (A1) 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.

[0060] 1-2. Polyamide Resin (A2) In the present embodiment, it is preferable that the polyamide resin composition further contains a polyamide resin (A2) having a heat of fusion (ΔH) measured by a differential scanning calorimeter (DSC) of 0 J / g or more and 5 J / g or less.

[0061] Since the polyamide resin (A2) has lower crystallinity than the polyamide resin (A1), the degree of crystallinity of the polyamide resin composition during molding can be reduced. This reduces the shrinkage rate of a resin member containing the polyamide resin composition, thereby reducing the stress generated between the resin member and a metal member. As a result, it is thought that stress is less likely to accumulate in the resin member when the ambient temperature is lowered, making it less likely for cracks to occur in the resin member.

[0062] The polyamide resin (A2) preferably has a melting point (Tm) that is not substantially measurable by differential scanning calorimetry (DSC). The phrase "having a melting point (Tm) that is not substantially measurable" means that a transition point corresponding to the melting point is not substantially observed in the above-mentioned measurement method.

[0063] The heat of fusion (ΔH) of the polyamide resin (A2) is 0 J / g or more and 5 J / g or less, and preferably 0 J / g. The polyamide resin (A2) is preferably amorphous. The heat of fusion (ΔH) of the polyamide resin (A2) can be measured by the same method as that described for the polyamide (A1).

[0064] The polyamide resin (A2) is not particularly limited as long as it is a polyamide resin having a heat of fusion (ΔH) of 0 J / g or more and 5 J / g or less, but may be, for example, a polyamide containing a component unit (A2a) derived from a dicarboxylic acid and a component unit (A2b) derived from a diamine. Hereinafter, a case where the polyamide resin (A2) contains a component unit (A2a) derived from a dicarboxylic acid and a component unit (A2b) derived from a diamine will be described.

[0065] (Component Unit (A2a) Derived from Dicarboxylic Acid) The component unit (A2a) derived from a dicarboxylic acid preferably includes a component unit derived from isophthalic acid. By including a component unit derived from isophthalic acid, the crystallinity of the polyamide resin (A2) can be further reduced.

[0066] The content of the component units derived from isophthalic acid is preferably 40 mol% or more and 100 mol% or less, more preferably 50 mol% or more and 100 mol% or less, and even more preferably 65 mol% or more and 100 mol% or less, relative to the total number of moles (A2a) of components derived from dicarboxylic acids in the polyamide resin (A2). When the content of the isophthalic acid component units is 40 mol% or more, the crystallinity of the polyamide resin (A2) can be further reduced.

[0067] The dicarboxylic acid-derived component units (A2a) may further contain component units derived from other dicarboxylic acids other than the isophthalic acid-derived component units, as long as the effects of the present invention are not impaired. Examples of other dicarboxylic acids include aromatic dicarboxylic acids other than isophthalic acid, such as terephthalic acid, 2-methylterephthalic acid, and naphthalenedicarboxylic acid, aliphatic dicarboxylic acids, and alicyclic dicarboxylic acids. The aliphatic dicarboxylic acids and alicyclic dicarboxylic acids may be the same as the above-mentioned aliphatic dicarboxylic acids and alicyclic dicarboxylic acids, respectively. Of these, aromatic dicarboxylic acids other than isophthalic acid are preferred, and terephthalic acid is more preferred.

[0068] When the dicarboxylic acid-derived component units (A2a) further contain component units derived from terephthalic acid, the molar ratio of the isophthalic acid-derived component units to the terephthalic acid-derived component units (isophthalic acid-derived component units / terephthalic acid-derived component units) is preferably 55 / 45 to 95 / 5, more preferably 60 / 40 to 90 / 10, and even more preferably 60 / 40 to 80 / 20. When the molar ratio is within the above range, the crystallinity of the polyamide resin (A2) can be further reduced, and the occurrence of cracks at low temperatures in a resin workpiece containing the polyamide resin composition can be further suppressed, thereby further improving heat shock resistance.

[0069] (Component Unit (A2b) Derived from Diamine) The component unit (A2b) derived from diamine preferably includes a component unit derived from an aliphatic diamine having from 4 to 15 carbon atoms.

[0070] The polyamide resin (A2) is preferably a semi-aromatic polyamide resin in which the dicarboxylic acid-derived component units (A2a) include isophthalic acid-derived component units and the diamine-derived component units (A2b) include aliphatic diamine-derived component units having from 4 to 15 carbon atoms.

[0071] Examples of the aliphatic diamine having from 4 to 15 carbon atoms include those mentioned in connection with the polyamide resin (A1). Of these, the aliphatic diamine is preferably 1,6-diaminohexane.

[0072] The content of the component units derived from the aliphatic diamine is preferably 50 mol % or more and 100 mol % or less, and more preferably 60 mol % or more and 100 mol % or less, based on the total number of moles of the component units (A2b) derived from the diamine.

[0073] The diamine-derived unit (A2b) may further contain other diamine-derived unit(s) in addition to the aliphatic diamine-derived unit(s), as long as the effects of the present invention are not impaired. Examples of the other diamines include alicyclic diamines and aromatic diamines. Examples of the alicyclic diamines and aromatic diamines include those described for the polyamide resin (A1). The content of the other diamine-derived unit(s) can be, for example, 10 mol % or less based on the total number of moles of the diamine-derived unit(s) (A2b).

[0074] The respective structural units of the polyamide resin (A2) and their ratios can be calculated from the charge ratios when preparing the polyamide resin (A2) or measured by the NMR method. For the NMR method, the same method as described for the polyamide resin (A2) can be used.

[0075] The dicarboxylic acid-derived component units of the polyamide resin (A2) may include component units derived from a biomass-derived dicarboxylic acid, and the diamine-derived component units may include component units derived from a biomass-derived diamine. The polyamide resin (A2) may also be a biomass-derived polyamide resin (A2) obtained by polymerizing raw materials including a biomass-derived raw material.

[0076] Specific examples of the polyamide resin (A2) include polyamide 6I6T.

[0077] The polyamide resin (A2) can be produced by the same method as that for the polyamide resin (A1).

[0078] The content of polyamide resin (A2) is preferably 3% by mass or more and 25% by mass or less, and more preferably 5% by mass or more and 20% by mass or less, based on the total mass of polyamide resin (A1) and polyamide resin (A2). A content of 3% by mass or more further reduces the crystallinity of the polyamide resin composition, thereby further increasing the flexibility of the resin member and further suppressing cracking at low temperatures. Furthermore, a content of 25% by mass or less allows a sufficient amount of semi-oriented polyamide resin (A1) to be contained in the polyamide resin composition, thereby further increasing the mechanical strength (tensile strength and flexural strength) of the resin member containing the polyamide resin composition.

[0079] The content of the polyamide resin (A2) is preferably 2% by mass or more and 20% by mass or less, more preferably 2% by mass or more and 15% by mass or less, and even more preferably 2% by mass or more and 10% by mass or less, relative to the total mass of the polyamide resin composition.

[0080] (Physical Properties) The polyamide resin (A2) preferably has a glass transition temperature (Tg) measured by a differential scanning calorimeter (DSC) of more preferably more than 70°C and not more than 145°C, more preferably 75°C or more and not more than 140°C, and even more preferably 80°C or more and not more than 130°C.

[0081] The polyamide resin (A2) preferably has an intrinsic viscosity [η] of 0.4 dl / g or more and 1.6 dl / g or less, and more preferably 0.5 dl / g or more and 1.2 dl / g or less, as measured in 96.5% sulfuric acid at 25° C. The intrinsic viscosity [η] of the polyamide resin (A2) can be measured in the same manner as the intrinsic viscosity [η] of the polyamide resin (A1).

[0082] 1-3. Halogen-based flame retardant (B) In this embodiment, the polyamide resin composition contains a halogen-based flame retardant (B). The halogen-based flame retardant (B) can impart flame retardancy to the polyamide resin composition and a resin member containing the same. In this specification, the term "halogen-based flame retardant" refers to a halogen-containing compound that can impart flame retardancy to the polyamide resin composition. The halogen-based flame retardant (B) preferably contains at least one of brominated polystyrene and polybrominated styrene, and more preferably contains brominated polystyrene.

[0083] The content of the halogenated flame retardant (B) is preferably 25% by mass or more and 40% by mass or less, and more preferably 30% by mass or more and 35% by mass or less, based on the total mass of the thermoplastic resin and the halogenated flame retardant (B) contained in the polyamide resin composition. When the content is 30% by mass or more, the flame retardancy of the polyamide resin composition and the resin member containing the same can be further improved. Furthermore, when the content is 40% by mass or less, the aromatic ring concentration in the polyamide resin composition can be reduced, and the tracking resistance of the polyamide resin composition and the resin member containing the same can be further improved.

[0084] The content of the halogen-based flame retardant (B) is preferably 8% by mass or more and 25% by mass or less, and more preferably 12% by mass or more and 20% by mass or less, based on the total mass of the polyamide resin composition. By making the content 8% by mass or more, the flame retardancy of the polyamide resin composition and the resin member containing the same can be further improved. Furthermore, by making the content 25% by mass or less, the tracking resistance of the polyamide resin composition and the resin member containing the same can be further improved.

[0085] 1-4. Endothermic Filler (C) In this embodiment, the polyamide resin composition contains an endothermic filler (C). In this specification, the term "endothermic filler" refers to an inorganic filler that absorbs heat generated during discharge, etc. The endothermic filler (C) is preferably an inorganic compound that absorbs heat and causes its own decomposition reaction.

[0086] Examples of heat-absorbing filler materials include zinc borate (xZnO.yB２ O ３ ・zH ２O (wherein (x, y, z) may be any of (2,3,0), (4,1,0), (1,2,0), (1,1,0), (3,2,0), (2,3,3.5), (2,3,4), (2,3,5.5), (2,2,3), and (4,1,1), with (2,3,0), (4,1,0), (1,2,0), (1,1,0), and (3,2,0) being preferred (i.e., anhydrous zinc borate is preferred), and (2,3,0) being more preferred)), borate compounds such as magnesium borate, calcium borate, and aluminum borate, dimethyl phosphate, Calcium methylphosphinate, 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, methyl methyl-n-propylphosphinate, zinc methyl-n-propylphosphinate, calcium methane di(methylphosphinate), 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, zinc diphenylphosphinate, magnesium hydroxide, aluminum phosphate, aluminum oxide (alumina), transition alumina, boehmite (aluminum oxide monohydrate), aluminum silicate, aluminum hydroxide, etc. Of these, the endothermic filler (C) is preferably a borate compound, more preferably zinc borate.Borate compounds are less likely to produce compounds that can decompose polyamide resins when thermally decomposed. Therefore, the mechanical strength of resin parts is less likely to decrease due to the heat generated during kneading of the polyamide resin composition, and cracks are less likely to occur when the temperature changes from high to low. This can further improve the heat shock resistance of resin parts. Furthermore, zinc borate has a high decomposition onset temperature and a large heat absorption, which can further improve the tracking resistance of polyamide resin compositions and resin parts containing the same. Furthermore, since the zinc borate is anhydrous zinc borate, water is not released by the dehydration reaction, which can suppress degradation of polyamide resins and, as a result, can easily increase strength.

[0087] The volume average particle size (D50) of the endothermic filler (C) is preferably 0.1 μm or more and 30 μm or less, and more preferably 0.5 μm or more and 15 μm or less. In particular, when the endothermic filler (C) is a borate compound, the volume average particle size (D50) of the endothermic filler (C) is preferably within the above-mentioned range. By having the volume average particle size (D50) of the endothermic filler (C) be 0.5 μm or more, the endothermic filler (C) can be finely dispersed in the polyamide resin composition or in the resin part molded therefrom, which makes it less likely to cause a decrease in strength. Furthermore, by having the volume average particle size (D50) of the endothermic filler (C) be 30 μm or less, the specific surface area of ​​the endothermic filler (C) can be increased, making it easier to absorb heat generated by discharge. Furthermore, when the content of the endothermic filler (C) is the same, a volume average particle diameter (D50) of 30 μm or less allows a larger amount of the endothermic filler (C) to be dispersed in the polyamide resin composition or in the resin part molded therefrom, thereby reducing the average distance between the endothermic filler (C) and the polyamide resin (A1) or polyamide resin (A2), and making it easier to absorb the heat generated by discharge. This further improves the tracking resistance of the resin part. The volume average particle diameter (D50) can be measured using a laser diffraction method.

[0088] The content of the endothermic filler (C) is preferably 0.5% by mass or more and 10.0% by mass or less, more preferably 1.8% by mass or more and 10.0% by mass or less, based on the total mass of the polyamide resin composition. When the content is 0.5% by mass or more, the tracking resistance of the polyamide resin composition and the resin workpiece containing it can be more sufficiently improved. Furthermore, when the content is 10.0% by mass or less, the content of the polyamide resin (A1) can be sufficiently increased, and the mechanical strength of the resin workpiece can be sufficiently increased.

[0089] 1-5. Fibrous Reinforcement (D) In ​​this embodiment, the polyamide resin composition contains a fibrous reinforcing material (D) having a cross-sectional aspect ratio of 1.5 or more. In this specification, the "cross-section" of the fibrous reinforcing material (D) refers to a cross-section cut in a direction perpendicular to the longitudinal direction of the fiber. In addition, in this specification, the "aspect ratio" refers to the value of the ratio of the first line segment to the second line segment, where the longest line segment passing through the center of the cross-section and connecting opposing edges in the cross-section is defined as the first line segment and the second line segment is defined as the line segment perpendicular to the longest line segment.

[0090] The cross-sectional aspect ratio of the fibrous reinforcing material (D) is preferably 1.8 or more, more preferably 2.0 or more, even more preferably 3.0 or more, and particularly preferably 4.0 or more. When the aspect ratio is 1.8 or more, the length in the direction perpendicular to the length direction of the fibrous reinforcing material (D) (the flow direction of the polyamide resin composition during molding) becomes larger. Therefore, it is thought that the difference in linear expansion coefficient with the metal member in the perpendicular direction can be made smaller. This makes it less likely for cracks to occur in the resin member, and further improves the heat shock resistance of the resin member. For the same reason, when the aspect ratio is 2.0 or more, the heat shock resistance of the resin member is more sufficiently improved.

[0091] The aspect ratio can be determined by determining the weight-average major axis (Dw) and the weight-average minor axis (dw) of the fibrous reinforcing material (D) and calculating the ratio (Dw / dw) thereof by the method described below. The cross-sectional shape of the fibrous reinforcing material (D) is, for example, elliptical or flat.

[0092] The type of fibrous reinforcing material (D) is not particularly limited, and examples thereof include glass fiber, carbon fiber, wollastonite, potassium titanate whisker, calcium carbonate whisker, aluminum borate whisker, magnesium sulfate whisker, sepiolite, xonotlite, zinc oxide whisker, milled fiber, cut fiber, wholly aromatic polyamide fiber (e.g., polyparaphenylene terephthalamide fiber, polymetaphenylene terephthalamide fiber, polyparaphenylene isophthalamide fiber, polymetaphenylene isophthalamide fiber, and fiber obtained from a condensate of diaminodiphenyl ether with terephthalic acid or isophthalic acid), boron fiber, liquid crystal polyester fiber, etc. Among these, glass fiber and carbon fiber are preferred because they tend to increase the strength (rigidity) and heat resistance of the resulting resin member, and glass fiber is more preferred.

[0093] The weight average fiber diameter (Dw) of the fibrous reinforcing material (D) is, for example, 1 μm or more and 50 μm or less, and preferably 5 μm or more and 30 μm or less. The weight average fiber length (Lw) of the fibrous reinforcing material (D) is, for example, 10 μm or more and 3000 μm or less, and preferably 100 μm or more and 1000 μm or less. In this specification, the term "fiber diameter" refers to the length of the longest line segment (the first line segment) among the line segments connecting opposing edges in the cross section of the fibrous reinforcing material.

[0094] The weight-average fiber diameter (Dw) and average fiber length (Lw) of the fibrous reinforcing material (D) 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 the resulting filtrate is collected. 2) The filtrate obtained in 1) above is dispersed in water, and the major and minor diameters (Di, di; here, the major diameter refers to the first line segment in the fiber cross section, and the minor diameter refers to the second line segment) and fiber length (Li) of 300 randomly selected fibers are measured using an optical microscope (magnification: 50x). The number of fibers with a major diameter of Di is Ri, and the number of fibers with a minor diameter of di is ri. The weight-average diameters (weight-average major diameter Dw, weight-average minor diameter dw) are calculated based on the following formula, and these are the average major diameter and average minor diameter of the fibrous reinforcing material (D). Weight average major axis (Dw) = (ΣRi × Di ２ ) / (ΣRi×Di) Weight average short axis (dw)=(Σri×di ２ ) / (Σri×di) The weight average major axis (Dw) is defined as the weight average fiber diameter (Dw) of the fibrous reinforcing material.

[0095] In the above method, the number of fibers having a fiber length Li is similarly defined as qi, and the weight average length (Lw) is calculated based on the following formula, which is the average fiber length of the fibrous reinforcing material (D). Weight average fiber length (Lw) = (Σqi × Li ２ ) / (Σqi × Li)

[0096] The content of the fibrous reinforcing material (D) is preferably 20% by mass or more and 60% by mass or less, and more preferably 35% by mass or more and 50% by mass or less, relative to the total mass of the polyamide resin composition. A content of 20% by mass or more can further enhance the heat shock resistance of a resin member containing the polyamide resin composition. Furthermore, the inclusion of the fibrous reinforcing material (D) in the polyamide resin composition can further enhance the smoothness of the resin member, thereby reducing the irregularities on the surface of the resin member. Reducing the irregularities on the surface of the resin member can prevent the scintillation discharge that occurs when a voltage is applied to the resin member from concentrating on the convex portions. This can further suppress the precipitation of carbides due to the scintillation discharge concentrating at one location. As a result, the tracking resistance can be further improved, and by setting the content to 35% by mass or more, the tracking resistance can be further improved. Furthermore, by setting the content to 60% by mass or less, the flowability of the polyamide resin composition during molding can be less likely to decrease.

[0097] 1-6. Polyolefin Resin (E) In the present embodiment, the polyamide resin composition contains a polyolefin resin modified with an unsaturated carboxylic acid or a derivative thereof (hereinafter referred to as a "modified polyolefin resin").

[0098] The modified polyolefin resin (E) can be obtained by subjecting a polyolefin resin before modification to a modification reaction using a compound containing a carboxylic acid group (including a carboxylic acid anhydride group).

[0099] Examples of polyolefin resins before modification include ethylene polymers, propylene polymers, butene polymers, and copolymers of these olefins (e.g., ethylene-α-olefin copolymers), etc. Among these, ethylene polymers are preferred.

[0100] Examples of the α-olefin other than ethylene in the ethylene / α-olefin copolymer include propylene, 1-butene, 1-pentene, 1-hexene, 4-methyl-1-pentene, 1-octene, 1-decene, etc. Among these, propylene, 1-butene, 1-hexene, 4-methyl-1-pentene, and 1-octene are preferred.

[0101] Examples of compounds containing a carboxylic acid group include α,β-unsaturated carboxylic acids such as acrylic acid, methacrylic acid, maleic acid, fumaric acid, itaconic acid, and phthalic acid. Examples of compounds containing a carboxylic acid anhydride group include dicarboxylic acid anhydrides having an α,β-unsaturated bond such as maleic anhydride, itaconic anhydride, and phthalic anhydride. Of these, maleic anhydride is preferred. This increases the affinity between the polyamide resin (A1) and the modified polyolefin resin (E), making the modified polyolefin resin (E) more easily dispersible in the polyamide resin composition.

[0102] The content (modification amount) of carboxylic acid groups in the modified polyolefin resin (E) is preferably 0.1% by mass or more and 5.0% by mass or less, more preferably 0.2% by mass or more and 3.0% by mass or less, and even more preferably 0.5% by mass or more and 1.5% by mass or less. When the content of carboxylic acid groups is within the above range, the impact resistance and elongation of the resin composition tend to be improved.

[0103] The content (modification amount) of the carboxylic acid group in the modified polyolefin resin (E) can be calculated from the charge ratio when preparing the modified polyolefin resin, or can be measured by the NMR method. For the NMR method, the same method as described for the polyamide resin (A1) can be used.

[0104] A method in which a polyolefin resin before modification is subjected to a modification reaction using a compound containing a carboxylic acid group (including a carboxylic anhydride group) is, for example, a graft modification method.

[0105] Graft modification can be carried out by various conventionally known methods. For example, it may be carried out by a melt modification method in which the polyolefin resin before modification is melted using an extruder and a graft monomer is added to carry out graft copolymerization, or it may be carried out by a solution modification method in which the polyolefin resin before modification is dissolved in a solvent and a graft monomer is added to carry out graft copolymerization. In either case, it is preferable to carry out the reaction in the presence of a radical initiator in order to efficiently graft copolymerize the graft monomer.

[0106] The content of the modified polyolefin resin (E) is 2% by mass or more, preferably 2% by mass or more and 10% by mass or less, more preferably 3% by mass or more and 8% by mass or less, and even more preferably 3% by mass or more and 6% by mass or less, based on the total mass of the polyamide resin composition. By making the content 2% by mass or more, the flexibility of the resin member containing the polyamide resin composition can be increased, and the heat shock resistance of the resin member can be improved.

[0107] 1-7. Other Components The polyamide resin composition may contain other known components.

[0108] Examples of other components include flame retardant aids, nucleating agents, lubricants, colorants, inorganic particles, heat stabilizers, 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 other than those mentioned above (lactone compounds, vitamin E compounds, hydroquinones, etc.), light stabilizers (benzotriazoles, triazines, benzophenones, benzoates, hindered amines, oxanilides, etc.), and the like.

[0109] (Flame Retardant Synergist) Examples of the flame retardant synergist include metal oxides and metal hydroxides. Specifically, zinc stannate, iron oxide, zinc oxide, and tin oxide are preferred.

[0110] The content of the flame retardant aid is preferably 0.5% by mass or more and 5.0% by mass or less, and more preferably 1.0% by mass or more and 3.0% by mass or less, based on the total mass of the polyamide resin composition.

[0111] (Nucleating Agent) The nucleating agent can promote the crystallization of the polyamide resin (A1), thereby further increasing the tensile strength and elastic modulus of the resin member.

[0112] Examples of nucleating agents 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 resin member. These nucleating agents may be used alone or in combination of two or more.

[0113] Talc is generally a hydrous magnesium silicate (SiO ２ :58~64%, MgO:28~32%, Al ２ O ３ :0.5~5%, Fe ２ O ３ : 0.3 to 5%) as a main component. The average particle size of talc is not particularly limited, but is preferably 1 to 15 μm. When the average particle size of talc is within the above range, talc can be easily dispersed in polyamide resin (A1) without impairing the fluidity of the polyamide resin composition. From the same viewpoint, the average particle size of talc is more preferably 1 to 7.5 μm. The average particle size of talc can be measured by laser diffraction, for example, using a Shimadzu particle size distribution analyzer (SALD-2000A model) manufactured by Shimadzu Corporation.

[0114] The content of the nucleating agent is preferably 0.10 parts by mass or more and 5.00 parts by mass or less, and more preferably 0.10 parts by mass or more and 3.00 parts by mass or less, relative to the total mass of the polyamide resin composition. When the content of the nucleating agent is within the above range, the crystallinity of the resin member is easily sufficiently increased, and sufficient mechanical strength is easily obtained.

[0115] (Lubricant) The lubricant improves the injection flowability of the polyamide resin composition and improves the appearance of the resulting resin part. 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.

[0116] The oxycarboxylic acid constituting the oxycarboxylic acid metal salt may be an aliphatic oxycarboxylic acid or an aromatic oxycarboxylic acid. Examples of the aliphatic oxycarboxylic acid 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 the aromatic oxycarboxylic acid include salicylic acid, m-hydroxybenzoic acid, p-hydroxybenzoic acid, gallic acid, mandelic acid, and trovic acid.

[0117] 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.

[0118] 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.

[0119] Examples of the higher fatty acid that constitutes 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.

[0120] Examples of metals constituting the above higher fatty acid metal salts include calcium, magnesium, barium, lithium, aluminum, zinc, sodium, and potassium.

[0121] Of these, the higher fatty acid metal salts are preferably calcium stearate, magnesium stearate, barium stearate, calcium behenate, sodium montanate, and calcium montanate.

[0122] The content of the lubricant is preferably 0.01% by mass or more and 1.30% by mass or less relative to the total mass of the polyamide resin composition. When the content of the lubricant is 0.01% by mass or more, the flowability during molding tends to be improved, and the appearance of the obtained molded product tends to be improved. When the content of the lubricant is 1.30% by mass or less, gas due to decomposition of the lubricant is unlikely to be generated during molding, and the appearance of the product tends to be good.

[0123] (Colorant) The colorant imparts a desired color tone to the resin member. 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.

[0124] The content of the colorant is preferably 0.01% by mass or more and 5.00% by mass or less, and more preferably 0.10% by mass or more and 2.00% by mass or less, based on the total mass of the polyamide resin composition.

[0125] (Inorganic Particles) The polyamide resin composition may contain inorganic particles. The inorganic particles are preferably scale-like or plate-like inorganic particles. The inclusion of such inorganic particles increases the mechanical strength of the resin member, thereby suppressing the occurrence of cracks in the resin member when the temperature is changed from high to low. This further improves the heat shock resistance of the resin member. In this specification, "scale-like" or "plate-like" inorganic particles refer to inorganic particles whose surface is composed of multiple flat surfaces and whose area when observed from a predetermined angle (when viewed in plan) is larger than the area when observed from an angle perpendicular to the observation direction. More specifically, for "scale-like" or "plate-like" inorganic particles, the projected area when viewed in plan from the direction in which the projected area is largest is preferably 10 times the projected area when viewed in plan from the direction perpendicular to the above direction.

[0126] When the content of the fibrous reinforcing material (D) is less than 35% by mass relative to the total mass of the polyamide resin composition, inorganic particles are preferably contained in the polyamide resin composition, which makes it possible to further increase the mechanical strength of a resin workpiece containing the polyamide resin composition and further improve heat shock resistance while making it difficult for the flowability of the polyamide resin composition to decrease during molding due to an increase in the content of the fibrous reinforcing material (D).

[0127] Examples of inorganic particle materials include glass, mica, kaolin, clay, alumina, etc. Specific examples of inorganic particle types include glass flakes, mica particles, etc. When the inorganic particle material is mica, the mica is preferably white mica (muscovite). This is because white mica has high insulating properties among micas, and can therefore more sufficiently improve the tracking resistance of polyamide resin compositions and resin members containing the same.

[0128] The average particle size of the inorganic particles is preferably 50 μm or more and 600 μm or less, more preferably 100 μm or more and 600 μm or less. When the average particle size is 50 μm or more and 600 μm or less, the inorganic particles are well dispersed in the polyamide resin composition and the resin workpiece containing the same, improving the surface smoothness of the resin workpiece and improving tracking resistance. The average particle size of the inorganic particles can be measured by incinerating the polyamide resin composition or the resin workpiece at 600 ° C in an air atmosphere using an electric furnace, photographing the residue, and processing the resulting image. The particle sizes of at least five inorganic particles can be measured, and the average value can be used as the average particle size.

[0129] The aspect ratio (particle size / thickness) of the inorganic particles is preferably from 10 to 900, and more preferably from 20 to 500. The thickness of the inorganic particles refers to the shortest length from one surface of the inorganic particles to the other surface opposite to the surface.

[0130] The average thickness of the inorganic particles is preferably 0.5 μm or more and 10 μm or less, more preferably 0.5 μm or more and 8 μm or less. The average thickness of the inorganic particles can be measured by ashing the polyamide resin composition or the resin member in an air atmosphere at 600° C. using an electric furnace, photographing the residue with an SEM, and processing the resulting image. The thicknesses of at least five inorganic particles can be measured, and the average value can be used as the average thickness.

[0131] It is preferable that the inorganic particles are surface-treated with a surface treatment agent such as an epoxy compound, an isocyanate compound, an organic silane compound, an organic titanate compound, or an organic borane. By surface-treating the inorganic particles, the affinity between the inorganic particles and the polyamide resin (A1) can be increased. This can increase the interfacial strength between the inorganic particles and the polyamide resin (A1), thereby reducing the difference in linear expansion coefficient between the resin member and the metal member, and further improving the heat shock resistance of the resin member. The surface treatment agent is preferably an epoxy compound, an isocyanate compound, or an organic silane compound.

[0132] Examples of commercially available inorganic particles include glass flakes (Fleca REFG-315, Fleca REFG-312, Fleca REFG-301, all manufactured by Nippon Sheet Glass Co., Ltd.), mica particles (Repco Mica M-60, Repco Mica M-200, Repco Mica M-200HG, Repco Mica M-400, all manufactured by Repco Corporation), and the like.

[0133] The content of the inorganic particles is preferably 5% by mass or more and 30% by mass or less, and more preferably 5% by mass or more and 25% by mass or less, based on the total mass of the polyamide resin composition. When the content is 5% by mass or more, the smoothness of the surface of a resin workpiece containing the polyamide resin composition can be further increased, and the tracking resistance of the polyamide resin composition and the resin workpiece containing the same can be further improved.

[0134] 1-8. Method for Producing Polyamide Resin Composition The polyamide resin composition can be produced by a known resin kneading method, such as mixing the above-mentioned polyamide resin (A1), polyamide resin (A2), halogen-based flame retardant (B), endothermic filler (C), fibrous reinforcing material (D), modified polyolefin resin (E), and other components as needed, using a Henschel mixer, V-blender, ribbon blender, or tumbler blender, or by mixing, melt-kneading the resulting mixture in a single-screw extruder, multi-screw extruder, kneader, or Banbury mixer, followed by granulation or pulverization. The melting temperature during melt-kneading is preferably at least 10°C above the melting point (Tm) of the polyamide resin (A1) and not more than 20°C above the melting point (Tm).

[0135] 2. Metal-Resin Composite The metal-resin composite according to this embodiment includes a metal member and a resin member that is composited with the metal member and includes the polyamide resin composition described above.

[0136] 2-1. Resin member The resin member contains the polyamide resin composition described above. The proportion of the polyamide resin composition relative to the total mass of the resin member is preferably 50.00% by mass or more, more preferably 60.00% by mass or more, and even more preferably 70.00% by mass or more. The upper limit of the proportion of the polyamide resin composition relative to the total mass of the resin member is not particularly limited, but can be 100.00% by mass or less, or may be 90.00% by mass or less, or may be 80.00% by mass or less.

[0137] The material and shape of the metal member are not particularly limited as long as it is made of metal. For example, the material of the metal member can be iron, copper, nickel, gold, silver, platinum, cobalt, zinc, lead, tin, titanium, chromium, aluminum, magnesium, manganese, or an alloy such as stainless steel, brass, or phosphor bronze.

[0138] These materials can be selected depending on the application of the metal-resin composite. For example, when thermal conductivity is required, aluminum, aluminum alloys, magnesium, magnesium alloys, copper, and copper alloys are preferred, with copper and copper alloys being more preferred. Furthermore, when weight reduction and strength are required, aluminum, aluminum alloys, magnesium, and magnesium alloys are preferred.

[0139] The metal member preferably has a surface roughened. When the surface of the metal member is roughened, the polyamide resin composition melted or softened during molding penetrates into recesses formed on the surface of the metal member and solidifies, thereby firmly bonding the resin member containing the polyamide resin composition to the metal member. The method of roughening is not particularly limited, and the surface may be roughened by chemical treatment such as immersion in a treatment solution containing a base or acid or etching, or physical treatment such as laser or blasting.

[0140] The surface of the roughened metal member preferably has a center-to-center distance (pitch) of 5 nm or more and 500 μm or less between the multiple convex portions formed by the surface roughening treatment. When the center-to-center distance between the multiple convex portions is 5 nm or more, the recesses between the convex portions are appropriately large, making it easier for the resin member to sufficiently penetrate into the recesses during bonding, thereby further improving the bonding strength between the metal member and the resin member. Furthermore, when the center-to-center distance between the multiple convex portions is 500 μm or less, the recesses do not become too large, thereby further suppressing the formation of gaps at the metal-resin interface of the metal-resin composite and further improving airtightness. From the same perspective, the center-to-center distance between the multiple convex portions is more preferably 5 μm or more and 250 μm or less. The center-to-center distance between the multiple convex portions is the average value of the distance between the center of one convex portion and the center of the adjacent convex portion.

[0141] The center-to-center distance of the multiple convex portions can be measured by removing the resin member from the metal-resin composite by mechanical peeling, solvent washing, or the like, and observing the surface of the exposed metal member using an electron microscope or laser microscope, or a surface roughness measuring device.

[0142] Specifically, when the center-to-center distance between the multiple protrusions is less than 0.5 μm, the protrusions can be observed using an electron microscope, and when the center-to-center distance between the multiple protrusions is 0.5 μm or more, the protrusions can be observed using a laser microscope or a surface roughness measuring device. For example, in a photograph of the surface of a metal member taken with an electron microscope or a laser microscope, 50 random protrusions are selected and the center-to-center distance between each of these protrusions is measured. All the measured values ​​of the center-to-center distance between the protrusions are then added up and divided by 50 (average), which is then used as the "center-to-center distance between the multiple protrusions."

[0143] The average value of the ten-point average roughness (Rz) of the roughened surface of the metal member over an evaluation length of 4 mm is not particularly limited, but is preferably greater than 2 μm, more preferably greater than 2 μm and not greater than 50 μm, and even more preferably greater than 2.5 μm and not greater than 45 μm.

[0144] The average value of the ten-point average roughness (Rz) can be measured in accordance with JIS B0601 (ISO 4287). Specifically, the ten-point average roughness (Rz) is measured on a total of six straight line portions, including three arbitrary straight line portions parallel to each other and three arbitrary straight line portions perpendicular to the three arbitrary straight line portions, and the average value of these is taken as the average Rz value.

[0145] The average length of the roughness curve element (RSm) of the roughened surface of the metal member is preferably 0.5 μm or more and 500 μm or less. In particular, from the viewpoint of further increasing the bonding strength, it is preferable that the center-to-center distance between the plurality of convex portions is less than 0.5 μm and the average length of the roughness curve element (RSm) is 0.5 μm or more and 500 μm or less. The average length of the roughness curve element can also be measured according to JIS B0601 (ISO 4287) as described above.

[0146] 3. Method for Producing a Metal-Resin Composite The method for producing a metal-resin composite is not particularly limited, and may include, for example, the steps of: (1) preparing a metal member; (2) placing the metal member in a mold and injecting a molten polyamide resin composition into the mold; and (3) cooling the polyamide resin composition. The step (1) of preparing a metal member may include a step of roughening the surface of the metal member.

[0147] 3-1. Preparation of Metal Member First, the above-described metal member is prepared. At this time, at least a part of the surface of the metal member may be roughened, or a metal member having an uneven structure on at least a part of the surface may be prepared.

[0148] The method for roughening the surface of the metal member is not particularly limited. For example, a method using laser processing, an aqueous solution of an inorganic base such as NaOH, or HCl or HNO ３a method of treating a metal member by an anodic oxidation method; a displacement crystallization method in which etching is performed with an acid-based etching agent (preferably an acid-based etching agent aqueous solution containing an inorganic acid, ferric ions, cupric ions, and, if necessary, manganese ions, aluminum chloride hexahydrate, sodium chloride, etc.); a method of immersing a metal member in an aqueous solution of hydrazine hydrate, ammonia, a water-soluble amine compound, etc.; and a hot water treatment method.

[0149] 3-2. Insert molding Next, a metal member is placed in a mold, and the molten polyamide resin composition is injected into the mold to fill it, thereby combining (integrating) the softened or molten polyamide resin composition with the prepared metal member.

[0150] Specifically, the prepared metal member is first placed in a cavity (space) within an injection mold. Then, the polyamide resin composition is injected and filled into the cavity of the mold so that at least a portion of the polyamide resin composition contacts the metal member. This allows the injected molten polyamide resin composition to come into contact with the surface of the metal member. The temperature of the injection mold at this time is not particularly limited as long as it is a temperature at which the polyamide resin composition can be melted to a state suitable for injection molding, and can be, for example, 100 to 350°C.

[0151] As the mold, a known injection molding mold, for example, a mold for high speed heat cycle molding (RHCM, heat & cool molding) or a core back mold for foam molding can be used.

[0152] 3-3. Cooling Thereafter, the polyamide resin composition in contact with the surface of the metal member is cooled and solidified, thereby obtaining a metal resin composite in which the resin member containing the polyamide resin composition is composited with the metal member.

[0153] 4. Applications The above-described metal-resin composite is suitable for use in various applications where metal-resin composites are currently being used or where their application is being considered.

[0154] Examples of such applications include vehicle structural parts, vehicle mounted items, housings for electronic devices, housings for home appliances, structural parts, machine parts, various automobile parts, electronic device parts, household goods applications such as furniture and kitchen utensils, medical equipment, building material parts, other structural parts, and exterior parts.

[0155] More specifically, examples of the above applications include, in the vehicle field, instrument panels, console boxes, door handles, door trim, shift levers, pedals, glove boxes, bumpers, hoods, fenders, trunks, doors, roofs, pillars, seats, steering wheels, bus bars, terminals, motors, power conversion devices (inverters, converters), ECU boxes, electrical components, engine peripheral components, drivetrain / gear peripheral components, intake / exhaust system components, and cooling system components, etc. Precision electronic components include connectors, relays, gears, etc.

[0156] Furthermore, the metal-resin composite can be used in various home appliances, such as refrigerators, washing machines, vacuum cleaners, microwave ovens, air conditioners, lighting equipment, electric water heaters, televisions, clocks, ventilation fans, projectors, speakers, and other home appliances, as well as electronic information devices such as personal computers, mobile phones, smartphones, digital cameras, tablet PCs, portable music players, portable game consoles, chargers, and batteries, by combining the high thermal conductivity of the copper member with the insulating properties of the resin member.

[0157] Other example applications include components for lithium ion secondary batteries and robots.

[0158] For example, the metal-resin composite can be used in a bus bar unit of a mobile body (vehicle) such as an automobile.

[0159] 1 is a schematic diagram showing an exemplary embodiment of the metal-resin composite as a busbar unit. The busbar unit 100 includes a busbar 110, which is a conductive metal member (e.g., a copper metal member) and serves as a conductor for supplying current to each member, and a holding member 120, which is the resin member described above and serves as a protective member for protecting the busbar 110.

[0160] Of the surfaces of busbar 110, which is a metal member, the surface that comes into contact with retaining member 120 is roughened, and retaining member 120, which is a resin member (a resin member including a molded body of a polyamide resin composition), is joined to this roughened surface.

[0161] The bus bar unit 100 can be used to electrically connect a motor of a moving object and an inverter that controls the power supplied to the motor via the bus bar 110.

[0162] 2 is a diagram showing an exemplary configuration of a mobile body (vehicle) having the busbar unit 100. The mobile body 200 has a body 210, a power supply 220 such as a secondary battery that supplies power to drive the body 210, and a drive unit 230 that drives the body 210 with the power supplied from the power supply 220.

[0163] Drive unit 230 has an inverter 232 that controls the power (current) from power supply 220, a motor 234 that rotates by receiving the power controlled by inverter 232, and a bus bar unit 100 that has bus bars 110 that connect inverter 232 and motor 234. Motor 234 is housed in a motor case 236 together with a reducer 235 that converts the rotational speed obtained by motor 234 into a rotational speed for driving machine body 210. Bus bar unit 100 is attached to motor case 236, and bus bars 110 communicate from the inside to the outside of motor case 236 via bus bar unit 100.

[0164] The motor case 236 stores a coolant (coolant oil) for cooling the motor 234. The connection between the bus bar unit 100 and the motor case 236 is sealed with a sealing member such as an O-ring, thereby preventing oil from leaking from the inside of the motor case 236 to the outside.

[0165] In conventional busbar units, oil can leak from between the busbar and the resin protective member due to poor airtightness between the busbar and the protective member. In contrast, in this embodiment, the holding member 120, which is made of a resin member containing the above-described molded article of the polyamide resin composition, is joined with high airtightness to the busbar 110, which is a conductive metal member (e.g., a copper metal member), thereby suppressing oil leakage.

[0166] 2 shows an example in which the moving body 200 is a vehicle such as an automobile, but the moving body 200 is not particularly limited as long as it has a body and a drive unit and is capable of moving. For example, the moving body 200 may be a vehicle such as an automobile, a motorcycle, or an electric bicycle, as well as a railroad car, a ship, an airplane, a drone, or a robot.

[0167] The present invention will be described below with reference to examples, which should not be construed as limiting the scope of the present invention.

[0168] 1. Synthesis / preparation of materials 1-1. Synthesis of polyamide resin <Polyamide resin (PA-1) (6T66)> 2,800 g (24.1 mol) of 1,6-diaminohexane, 2,184 g (13.2 mol) of terephthalic acid, 1,572 g (10.8 mol) of adipic acid, 5.67 g (5.4 × 10) of sodium hypophosphite monohydrate as a catalyst －２82.4 g (0.67 mol) of benzoic acid as a molecular weight modifier, and 409 ml of ion-exchanged 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 raised to 3.02 MPa. After continuing the reaction for one hour, the low-order condensate was discharged into the atmosphere through a spray nozzle installed at the bottom of the autoclave and extracted. The low-order condensate 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. 5,440 g of polyamide precursor was obtained, having a water content of 3,000 ppm and an intrinsic viscosity [η] of 0.15 dl / g. The polyamide precursor was then dried and melt-polymerized using a twin-screw extruder at a cylinder set temperature of 330°C to obtain polyamide resin (PA-1).

[0169] The resulting polyamide resin (PA-1) had an intrinsic viscosity [η] of 0.8 dl / g, a melting point (Tm) of 310°C, a glass transition temperature (Tg) of 85°C, and a heat of fusion of 44 J / g. The resulting polyamide resin (PA-1) had a composition in which the content of component units derived from terephthalic acid among component units derived from dicarboxylic acid was 55 mol%, and the content of component units derived from adipic acid was 45 mol%. The content of component units derived from 1,6-diaminohexane among component units derived from diamine was 100 mol%.

[0170] <Polyamide resin (PA-2) (6T66)> 2,800 g (24.1 mol) of 1,6-diaminohexane, 2,184 g (13.2 mol) of terephthalic acid, 1,572 g (10.8 mol) of adipic acid, 5.67 g (5.4 × 10) of sodium hypophosphite monohydrate as a catalyst －２36.5 g (0.30 mol) of benzoic acid as a molecular weight modifier, and 409 ml of ion-exchanged 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 raised to 3.02 MPa. After continuing the reaction for one hour, the low-order condensate was discharged into the atmosphere through a spray nozzle installed at the bottom of the autoclave and extracted. The low-order condensate 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. 5440 g of polyamide precursor was obtained, having a water content of 3000 ppm and an intrinsic viscosity [η] of 0.15 dl / g. The polyamide precursor was then dried and melt-polymerized using a twin-screw extruder at a cylinder set temperature of 330°C to obtain polyamide resin (PA-2).

[0171] The resulting polyamide resin (PA-2) had an intrinsic viscosity [η] of 1.0 dl / g, a melting point (Tm) of 310°C, a glass transition temperature (Tg) of 85°C, and a heat of fusion of 44 J / g. The resulting polyamide resin (PA-2) had a composition in which the content of component units derived from terephthalic acid among the component units derived from dicarboxylic acid was 55 mol% and the content of component units derived from adipic acid was 45 mol%. The content of component units derived from 1,6-diaminohexane among the component units derived from diamine was 100 mol%.

[0172] <Polyamide Resin (PA-3) (6T6I)> 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 started at 190 ° C, and the internal temperature was raised to 250 ° C over 3 hours. At this time, the internal pressure of the autoclave was raised to 3.03 MPa. After continuing the reaction for 1 hour, the mixture was released into the atmosphere from a spray nozzle installed at the bottom of the autoclave, and a low-order condensate was extracted. Thereafter, this low-order condensate was 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 resulting low-order condensate had a water content of 4,100 ppm and an intrinsic viscosity [η] of 0.15 dl / g.

[0173] Next, this low-order condensate was placed in a tray-type solid-state polymerization reactor, and after purging with nitrogen, the reactor was heated to 180°C over approximately 1 hour and 30 minutes. The reaction was then continued for 1 hour and 30 minutes, and the temperature was then lowered to room temperature. The intrinsic viscosity [η] of the resulting prepolymer was 0.20 dL / g.

[0174] Thereafter, the obtained prepolymer was melt-polymerized in a twin-screw extruder having a screw diameter of 30 mm and an L / D ratio of 36 at a barrel set temperature of 330°C, a screw rotation speed of 200 rpm, and a resin supply rate of 6 kg / h to obtain a polyamide resin (PA-3).

[0175] The resulting polyamide resin (PA-3) had an intrinsic viscosity [η] 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 of 50 J / g. The resulting polyamide resin (PA-3) had a composition in which the content of component units derived from terephthalic acid among component units derived from dicarboxylic acid was 70 mol%, and the content of component units derived from isophthalic acid was 30 mol%. The content of component units derived from 1,6-diaminohexane among component units derived from diamine was 100 mol%.

[0176] <Polyamide Resin (PA-4) (6TDT)> Polyamide Resin (PA-4) was obtained in the same manner as in the synthesis of Polyamide Resin (PA-3), except that the raw materials were changed to 3655 g (22.0 mol) of terephthalic acid, 1312 g (11.3 mol) of 1,6-diaminohexane, and 1312 g (11.3 mol) of 2-methyl-1,5-diaminopentane.

[0177] The resulting polyamide resin (PA-4) had an intrinsic viscosity [η] of 0.9 dl / g, a melting point (Tm) of 300°C, a glass transition temperature (Tg) of 140°C, and a heat of fusion of 40 J / g. The resulting polyamide resin (PA-4) had a composition in which the content of component units derived from terephthalic acid among component units derived from dicarboxylic acid was 100 mol%. The content of component units derived from 1,6-diaminohexane among component units derived from diamine was 50 mol%, and the content of component units derived from 2-methyl-1,5-pentanediamine was 50 mol%.

[0178] 1-2. Synthesis of Polyamide Resin (B) <Polyamide Resin (PA-5) (6I6T)> 2800 g (24.1 mol) of 1,6-hexanediamine, 1196 g (7.2 mol) of terephthalic acid, 2774 g (16.7 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 an autoclave with a capacity of 13.6 L and purged with nitrogen. Stirring was initiated at 190°C, and the internal temperature was raised to 250°C over 3 hours. At this time, the internal pressure of the autoclave was raised to 3.03 MPa. After continuing the reaction for 1 hour, the mixture was released into the atmosphere from a spray nozzle installed at the bottom of the autoclave, and the low-order condensate was extracted. Thereafter, this low condensate was cooled to room temperature, and then pulverized to a particle size of 1.5 mm or less using a pulverizer, and dried for 24 hours at 110° C. The water content of the obtained low condensate was 4100 ppm, and the intrinsic viscosity [η] was 0.15 dl / g.

[0179] 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 approximately 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 resulting prepolymer was 0.20 dl / g. The resulting prepolymer was then melt-polymerized in a twin-screw extruder with a screw diameter of 30 mm and L / D = 36, with 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 (PA-5).

[0180] The intrinsic viscosity [η] of the obtained polyamide resin (PA-5) was 0.54 dl / g, the melting point (Tm) was not measured, the glass transition temperature (Tg) was 125°C, and the heat of fusion (ΔH) was 0 J / g.

[0181] 1-3. Halogen-based flame retardant (B) Brominated polystyrene (HP-3010, manufactured by Albemarle) was used.

[0182] 1-4. Endothermic Filler (C) Zinc borate (Fire Brake 500, manufactured by US Borax, volume average particle size (D50): 9 μm) was used.

[0183] 1-5. Fibrous Reinforcement (D) Reinforcement (D-1): Glass fiber (CSG-3PA820S, manufactured by Nitto Boseki Co., Ltd., aspect ratio of cross-sectional shape: 4, weight average fiber diameter (Dw): 7 μm) Reinforcement (D-2): Glass fiber (CSG-3PL-820, manufactured by Nitto Boseki Co., Ltd., aspect ratio of cross-sectional shape: 2, weight average fiber diameter (Dw): 10 μm)

[0184] 1-6. Synthesis of Modified Polyolefin Resin (E) A catalyst solution was obtained by adding 0.63 mg of bis(1,3-dimethylcyclopentadienyl)zirconium dichloride to a glass flask thoroughly purged with nitrogen, followed by 1.57 ml of a toluene solution of methylaminoxane (Al; 0.13 mmol / L) and 2.43 ml of toluene. Next, 912 ml of hexane and 320 ml of 1-butene were introduced into a 2-liter stainless steel autoclave thoroughly purged with nitrogen, and the temperature inside the system was raised to 80°C. Subsequently, 0.9 mmol of triisobutylaluminum and 2.0 ml of the catalyst solution prepared above (0.0005 mmol as Zr) were pressure-charged into the system with ethylene to initiate the polymerization reaction. The total pressure was maintained at 8.0 kg / cm2-G by continuously supplying ethylene, and the polymerization was carried out at 80°C for 30 minutes. A small amount of ethanol was introduced into the system to terminate the polymerization, and then unreacted ethylene was purged. The resulting solution was poured into a large excess of methanol to precipitate a white solid. This white solid was collected by filtration and dried overnight under reduced pressure to obtain a white solid (ethylene-1-butene copolymer).

[0185] The ethylene content of the ethylene-1-butene copolymer was 81 mol %. The density was 0.860 g / cm ３ The MFR (ASTM D 1238, 190°C, 2.16 kg load) was 0.5 g / 10 min, and the melting point was 35°C.

[0186] 100 parts by mass of the obtained ethylene-1-butene copolymer was mixed with 1.0 part by mass of maleic anhydride and 0.04 part by mass of peroxide (Perhexyne 25B, manufactured by NOF Corporation). The obtained mixture was melt-graft-modified in a twin-screw extruder set at 230°C to obtain a modified polyolefin resin.

[0187] The content (modification amount) of component units derived from maleic anhydride in the obtained modified polyolefin resin was 0.8 mass %. The density was 0.866 g / cm ３ The MFR was 0.27 g / 10 min.

[0188] 1-7. Other Components 1-7-1. Colorant Carbon black was used.

[0189] 1-7-2. Lubricant Calcium montanate was used.

[0190] 1-7-3. Flame retardant synergist Flame retardant synergist 1: Hydrotalcite (NAOX-33, manufactured by Toda Kogyo Co., Ltd.) Flame retardant synergist 2: Sodium antimonate (SA-A, manufactured by Nippon Seiko Co., Ltd.)

[0191] 1-7-4. Nucleating agent Talc (average particle size 6 μm) was used.

[0192] 1-7-5. Inorganic particles Glass flakes (Fleka REFG-315, manufactured by Nippon Sheet Glass Co., Ltd., average thickness 5 μm) were used.

[0193] 1-7-6. Fibrous reinforcement (aspect ratio less than 1.5) Glass fiber (CS03JA FT789, manufactured by Owens Corning Japan Co., Ltd., aspect ratio of cross-sectional shape: 1)

[0194] 2. Measurement The physical properties of each of the above resins were measured by the following methods.

[0195] <Melting Point (Tm) and Glass Transition Temperature (Tg)> The melting point (Tm) and glass transition temperature (Tg) of the polyamide resin were measured using a differential scanning calorimetry (DSC220C, manufactured by Seiko Instruments Inc.). Specifically, approximately 5 mg of polyamide resin was sealed in an aluminum pan for measurement and set in the differential scanning calorimetry. The polyamide resin was then heated from room temperature to 350°C at 10°C / min. To completely melt the resin, the pan was held at 350°C for 3 minutes and then cooled to 30°C at 10°C / min. After leaving the pan at 30°C for 5 minutes, the pan 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 crystallization temperature of the aliphatic polyamide resin (B) was determined as the temperature (° C.) at the exothermic peak during the cooling process.

[0196] <Heat of fusion (ΔH)> The heat of fusion (ΔH) of a polyamide resin was determined from the area of ​​the exothermic peak of crystallization in the first temperature rise process in accordance with JIS K 7122 (2012).

[0197] <Intrinsic Viscosity [η]> The intrinsic viscosity [η] of a polyamide resin was determined by dissolving 0.5 g of the polyamide resin in 50 ml of a 96.5% sulfuric acid solution, measuring the flow time of the resulting solution at 25°C ± 0.05°C using an Ubbelohde viscometer, and calculating the flow time in seconds using the formula: [η] = ηSP / (C(1 + 0.205ηSP)) [η]: intrinsic viscosity (dl / g) ηSP: specific viscosity C: sample concentration (g / dl) t: flow time in seconds (seconds) of the sample solution t ０ : Number of seconds for blank sulfuric acid to flow (seconds) ηSP = (t - t ０ ) / t ０

[0198] <Modification Amount> The content (% by mass) of component units derived from maleic anhydride in the modified polyolefin resin (modification amount) was measured by NMR under the following conditions: Measurement apparatus: Nuclear magnetic resonance apparatus (ECP500, manufactured by JEOL Ltd.) Observation nuclei: １３ C (125 MHz) Sequence: Single pulse proton decoupling Pulse width: 4.7 μsec (45° pulse) Repetition time: 5.5 sec Number of accumulations: 10,000 or more Solvent: Mixed solvent of orthodichlorobenzene / deuterated benzene (volume ratio: 80 / 20) Sample concentration: 55 mg / 0.6 mL Measurement temperature: 120°C Reference value of chemical shift: 27.50 ppm

[0199] <Density> The density of the modified polyolefin resin was measured at a temperature of 23°C using a density gradient tube in accordance with JIS K7112:1999.

[0200] <MFR> MFR was measured in accordance with ASTM D1238 (2023) at 190°C under a load of 2.16 kg.

[0201] 3. Preparation of Polyamide Resin Compositions The above materials were mixed in a tumbler blender in the composition ratios (units: parts by mass) shown in Tables 1 to 4, 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 pellet-shaped polyamide resin compositions 1 to 21.

[0202] 4. Evaluation <Flowability> Each 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 resin composition in the mold was measured: Injection molding machine: Tupearl TR40S3A (manufactured by Sodick Plastec Co., Ltd.) Injection pressure: 2000 kg / cm ２ Cylinder temperature setting: Polyamide resin melting point + 10°C Mold temperature: 120°C

[0203] <Tensile strength and gauge length elongation> Each polyamide resin composition was injection molded under the following conditions to obtain an ISO dumbbell-shaped test piece Type A having a thickness of 4.0 mm: Injection molding machine: EC75N (manufactured by Toshiba Machine Co., Ltd.) Molding machine cylinder temperature: melting point of polyamide resin + 10°C Mold temperature: 160°C

[0204] The obtained test piece was left for 24 hours in a nitrogen atmosphere at a temperature of 23° C. Then, a tensile test was carried out in an atmosphere at a temperature of 23° C. in accordance with ISO 527 to measure the tensile strength and the gage length elongation.

[0205] <Flexural Strength, Deflection, Flexural Modulus, and Fracture Energy> Each polyamide resin composition was injection molded under the following molding conditions to obtain a 4.0 mm-thick ISO dumbbell-shaped test piece Type A. Molding machine: EC75N-2A (Shibaura Machine Co., Ltd.) Molding machine cylinder temperature: Melting point of polyamide resin + 10°C Mold temperature: 120°C The obtained test piece was left at a temperature of 23°C in a nitrogen atmosphere for 24 hours. Next, a bending test was performed using a bending tester (NTESCO AB5) at a temperature of 23°C and a relative humidity of 50% in an atmosphere, with a span of 51 mm and a bending speed of 5 mm / min, to measure the bending strength (MPa), deflection (mm), flexural modulus (MPa), and fracture energy (mJ).

[0206] <Tracking Resistance (CTI)> Each polyamide resin composition was molded using the following injection molding machine under the following molding conditions to obtain rectangular parallelepiped test pieces measuring 200 mm x 130 mm x 3 mm. Molding machine: EC75N-2A (manufactured by Toshiba Machine Co., Ltd.) Cylinder temperature: melting point of polyamide resin + 10°C Mold temperature: 120°C

[0207] The comparative tracking index (CTI [V]), an index of tracking resistance, was measured for the obtained test specimens under the following conditions in accordance with IEC 60112 (2020). A higher CTI value indicates better tracking resistance. Test solution: Aqueous solution of ammonium chloride (concentration 0.1%) Testing machine: YST-1000V (manufactured by Yamayo Testing Instruments, Ltd.)

[0208] <Flame Retardancy> Each polyamide resin composition was injection molded under the following conditions to prepare 1 / 32 inch x 1 / 2 x 5 inch test pieces. Using the prepared test pieces, a vertical combustion test was carried out in accordance with the UL94 standard (UL Test No. UL94 dated June 18, 1991) to evaluate flame retardancy. Molding machine: Tupearl TR40S3A (manufactured by Sodick Plastec Co., Ltd.) Molding machine cylinder temperature: melting point of polyamide resin + 10°C Mold temperature: 120°C

[0209] <Heat shock resistance> An insert member (54 mm × 54 mm × 2 mm) made of S45C as specified in JIS G4051:2016 (carbon steel for mechanical structures) was placed in a metal insert molding mold attached to an injection molding machine (SE75EV, manufactured by Sumitomo Heavy Industries, Ltd.). Next, the various polyamide resin compositions were injection molded into the mold under conditions of a cylinder setting temperature of 320 ° C., a mold temperature of 120 ° C., and an injection speed of 50 mm / sec to prepare metal insert test pieces.

[0210] FIG. 3A is a perspective view showing the shape of a test piece prepared for evaluating heat shock resistance, FIG. 3B is a plan view of the test piece, and FIG. 3C is a cross-sectional view of the test piece taken along line A-A' in FIG. 3B. The numerical values ​​in FIGS. 3B and 3C indicate dimensions (unit: mm). As shown in FIGS. 3A to 3C, the upper, lower, and side surfaces of the insert member were covered by a 56.4 mm x 57 mm rectangular parallelepiped resin portion (1 mm thick on the upper and lower surfaces and 2 mm thick on the side surfaces (the same thickness as the insert member)) that was 1 mm larger than the four sides of the test piece in a plan view toward the gate portion (the Y direction in FIG. 3B), 2 mm larger in the direction opposite the gate portion (the direction opposite the Y direction in FIG. 3B), and 1.2 mm larger in each of the remaining two outward directions (the X direction and the opposite direction in FIG. 3B). However, in order to hold the insert member in the mold, a cutout portion was provided on each of the four sides of the test piece, in the shape of a right-angled isosceles triangle with two sides of 7 mm each, with the top and bottom surfaces of the test piece not covered with resin. The side surfaces of the test piece at the cutout were covered with resin. A 2 mm (outward direction: X direction and the opposite direction) x 4 mm (opposite the Y direction) x 2 mm (thickness) resin reservoir portion was provided at the end of the resin portion facing the gate portion in the outward direction (X direction and the opposite direction in Figure 3B) perpendicular to the resin flow direction, continuous with the resin portion covering the side surfaces of the test piece at the cutout. Furthermore, a resin reservoir portion was provided at the end of the resin portion facing the gate portion to prevent a weld from forming in the portion of the resin portion adjacent to the insert member.

[0211] A heat shock test was performed on this test piece using a thermal shock tester (manufactured by Espec Corporation), with one cycle consisting of -40°C / 30 minutes holding and 160°C / 30 minutes holding. The presence or absence of cracks was observed every five cycles, and the number of cycles until cracks occurred was measured. In Comparative Examples 7 and 8, the presence or absence of cracks was observed every 10 cycles. This measurement was performed five times for each test piece, and the average of the measured number of cycles was calculated. Note that a calculated number of 0 indicates that cracks occurred immediately after molding, and a number of 1 or more indicates that no cracks occurred immediately after molding.

[0212] The composition and evaluation results of each polyamide resin composition are shown in Tables 1 to 4. The numerical values ​​for the composition in Tables 1 to 4 represent parts by mass.

[0213]

[0214]

[0215]

[0216]

[0217] The results of polyamide resin compositions 1 to 11 show that a polyamide resin composition containing polyamide resin (A1), polyamide resin (A2), halogen-based flame retardant (B), heat-absorbing filler (zinc borate) (C), fibrous reinforcing material (D) having a cross-sectional aspect ratio of 1.5 or more, and modified polyolefin resin (E) can realize a polyamide resin composition that is excellent in all of heat shock resistance, tracking resistance, and flame retardancy.

[0218] This application claims priority from Japanese Patent Application No. 2024-047912, filed March 25, 2024. The entire disclosures of the specification, claims, and drawings of said application as originally filed are incorporated herein by reference.

[0219] The polyamide resin composition of the present invention is useful, for example, for insert-molded articles (for example, automobile parts).

[0220] 100 Bus bar unit 110 Bus bar 120 Holding member

Claims

1. A polyamide resin composition for insert molding, comprising: a polyamide resin (A1) having a melting point of 280°C or higher as measured by differential scanning calorimetry (DSC); a halogen-based flame retardant (B); an endothermic filler (C); a fibrous reinforcing material (D) having a cross-sectional aspect ratio of 1.5 or higher; and a polyolefin resin (E) modified with an unsaturated carboxylic acid or a derivative thereof, wherein the content of the polyolefin resin (E) is 2 mass% or more relative to the total mass of the polyamide resin composition.

2. The polyamide resin composition according to claim 1, further comprising a polyamide resin (A2) having a heat of fusion (ΔH) measured by differential scanning calorimetry (DSC) of 0 J / g or more and 5 J / g or less.

3. The polyamide resin composition according to claim 1, wherein the content of the halogenated flame retardant (B) is 30% by mass or more and 40% by mass or less, based on the total mass of the thermoplastic resin and the halogenated flame retardant (B) contained in the polyamide resin composition.

4. The polyamide resin composition according to claim 1, wherein the content of the endothermic filler (C) is 1.0 mass % or more and 10.0 mass % or less based on the total mass of the polyamide resin composition.

5. The polyamide resin composition according to claim 4, wherein the content of the endothermic filler (C) is 3.5 mass % or more and 10.0 mass % or less based on the total mass of the polyamide resin composition.

6. The polyamide resin composition according to claim 1, wherein the endothermic filler (C) is zinc borate.

7. The polyamide resin composition according to claim 1, wherein the content of the fibrous reinforcing material (D) is 35 mass % or more based on the total mass of the polyamide resin composition.

8. The polyamide resin composition according to claim 1, wherein the cross-sectional aspect ratio of the fibrous reinforcing material (D) is 3.0 or more.

9. A metal resin composite comprising: a metal member; and a resin member comprising the polyamide resin composition according to any one of claims 1 to 8, composited with the metal member.

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