Polyamide resin composition and metal resin joined body

Abstract

To provide a polyamide resin composition for insert molding capable of heightening airtightness between a metal member and a resin member even when subjecting to insert molding with a die at a low temperature, and a metal resin joined body using the same.SOLUTION: A polyamide resin composition for joining a metal member includes: a half aromatic polyamide resin (A); and an aliphatic polyamide resin (B) including at least one of a constituent unit derived from a dicarboxylic acid having 10 or more carbon atoms, a constituent unit derived from a diamine having 10 or more carbon atoms, a constituent unit derived from a lactam having 10 or more carbon atoms, and a constituent unit derived from an aminocarboxylic acid having 10 or more carbon atoms, wherein a ratio of a content of the aliphatic polyamide resin (B) to a total mass of the half aromatic polyamide resin (A) and the aliphatic polyamide resin (B) is 0.15 or more and 0.25 or less.SELECTED DRAWING: Figure 1

Description

Technical Field

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

Background Art

[0002] Conventionally, polyamide resin compositions are known as molding materials. Polyamide resin compositions are widely used, for example, as materials for various parts such as automotive parts and electrical and electronic parts, and are known to have excellent mechanical strength of the molded body.

[0003] By the way, a polyamide resin composition may be used to form a metal-resin bonded body in which a resin member formed by molding the polyamide resin composition and a metal member are bonded. When a polyamide resin composition is used for metal-resin bonding applications, it is required to firmly bond the resin member and the metal member.

[0004] For example, Patent Document 1 discloses a metal-resin composite having a metal member having irregularities on its surface and a resin member bonded to the surface of the metal member having the irregular structure, wherein the resin member is made of a polyamide resin composition for metal bonding containing a polyamide resin, a reinforcing filler, and a specific amount of talc. In Patent Document 1, it is said that the bonding strength between the metal member and the resin member is enhanced in the metal-resin composite.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] Incidentally, depending on the use of the bonded body of the polyamide resin composition and the metal member, airtightness between the polyamide resin composition and the metal member is required. For example, when using the above bonded body as a conductive component such as a bus bar for electrically connecting a motor disposed in a motor case filled with cooling oil and an inverter disposed outside the motor case, high airtightness is required to prevent oil leakage to the outside of the motor case. Further, from the viewpoint of reducing the manufacturing cost of the metal resin bonded body, it is required to lower the heating temperature of the mold during manufacturing. According to the study by the present inventors, in the polyamide resin composition used in Patent Document 1, when molding the metal resin bonded body with a low mold temperature, the airtightness between the metal member and the resin member could not be sufficiently enhanced.

[0007] An object of the present invention is to provide a polyamide resin composition for bonding to a metal member, which can enhance the airtightness between the metal member and the resin member even when molding the metal resin bonded body with a low mold temperature, and a metal resin bonded body using the same.

Means for Solving the Problems

[0008] One aspect of the present invention for solving the above problems relates to the polyamide resin composition of the following [1] to [7]. [1] A polyamide resin composition for bonding to a metal member, a semi-aromatic polyamide resin (A) having a melting point measured by a differential scanning calorimeter (DSC) of 290°C or higher and 340°C or lower, an aliphatic polyamide resin (B) containing at least one of a component unit derived from a dicarboxylic acid having 10 or more carbon atoms, a component unit derived from a diamine having 10 or more carbon atoms, a component unit derived from a lactam having 10 or more carbon atoms, and a component unit derived from an aminocarboxylic acid having 10 or more carbon atoms, and The ratio of the content of the aliphatic polyamide resin (B) to the total mass of the semi-aromatic polyamide resin (A) and the aliphatic polyamide resin (B), ((B) / ((A)+(B))), is 0.15 or more and 0.25 or less. Polyamide resin composition. [2] The semi-aromatic polyamide resin (A) contains a component unit (Aa) derived from a dicarboxylic acid and a component unit (Ab) derived from a diamine. The component unit (Aa) derived from the dicarboxylic acid contains a component unit derived from terephthalic acid. The component unit (Ab) derived from the diamine contains a component unit derived from 1,6-diaminohexane. The polyamide resin composition according to [1]. [3] The aliphatic polyamide resin (B) contains either a component unit derived from a lactam having 10 or more carbon atoms or a component unit derived from an aminocarboxylic acid having 10 or more carbon atoms. The polyamide resin composition according to [1] or [2]. [4] The melting point of the aliphatic polyamide resin (B) is 200°C or lower. The polyamide resin composition according to any one of [1] to [3]. [5] The glass transition temperature of the aliphatic polyamide resin (B) is 70°C or lower. The polyamide resin composition according to any one of [1] to [4]. [6] The polyamide resin composition further contains a reinforcing material having a content of 20% by mass or more and 40% by mass or less based on the total mass of the polyamide resin composition. The polyamide resin composition according to any one of [1] to [5]. [7] The difference between the melting point of the polyamide resin composition and the crystallization temperature of the polyamide resin composition, measured by a differential scanning calorimeter (DSC), is 26°C or more. The polyamide resin composition according to any one of [1] to [6].

[0009] One aspect of the present invention for solving the above problems relates to the metal resin composite of the following [8]. [8] A metal member and a resin member including the polyamide resin composition according to any one of [1] to [7], which is joined to the surface of the metal member. Metal-resin bonded body.

Effect of the Invention

[0010] According to the present invention, there is provided a polyamide resin composition for bonding to a metal member, which can enhance the airtightness between the metal member and the resin member even when the metal-resin bonded body is molded with a low mold temperature, and a metal-resin bonded body using the same.

Brief Description of the Drawings

[0011]

Figure 1

Figure 2

Mode for Carrying Out the Invention

[0012] Hereinafter, embodiments of the present invention will be described in detail. It should be noted that the present invention is not limited to the following embodiments.

[0013] 1. Polyamide resin composition The polyamide resin composition according to this embodiment is a polyamide resin composition for bonding to a metal member, and includes a semi-aromatic polyamide resin (A) having a melting point measured by a differential scanning calorimetry (DSC) of 290°C or higher and 340°C or lower, and an aliphatic polyamide resin (B). The above aliphatic polyamide resin (B) includes at least one of a component unit derived from a dicarboxylic acid having 10 or more carbon atoms, a component unit derived from a diamine having 10 or more carbon atoms, a component unit derived from a lactam having 10 or more carbon atoms, and a component unit derived from an aminocarboxylic acid having 10 or more carbon atoms. The ratio ((B) / ((A)+(B))) of the content of the above aliphatic polyamide resin (B) to the total mass of the above semi-aromatic polyamide resin (A) and the above aliphatic polyamide resin (B) is 0.15 or more and 0.25 or less.

[0014] The inventors have found that by using the above polyamide resin composition, even when molding a metal-resin bonded body with a low mold temperature, the airtightness between the metal member and the resin member can be improved.

[0015] Since the semi-aromatic polyamide resin (A) has a high melting point and high crystallinity, the mechanical strength of the resin member and the mold release property from the mold can be improved. On the other hand, when the mold temperature is low during molding, when the polyamide resin composition containing the semi-aromatic polyamide resin (A) is filled into the mold, it will solidify quickly. Therefore, when molding the metal-resin bonded body, the polyamide resin composition cannot enter the concave portions of the minute irregularities present on the surface of the metal member, and the airtightness between the resin member and the metal member is not sufficiently increased.

[0016] On the other hand, by adding an aliphatic polyamide resin (B) containing a component unit derived from a component having 10 or more carbon atoms to the semi-aromatic polyamide resin (A) to the polyamide resin composition, the above airtightness can be enhanced. Since the aliphatic polyamide resin (B) has a low melting point and glass transition temperature, the polyamide resin composition containing these has low fluidity and solidifies gently even when the mold temperature is low. As a result, the polyamide resin composition can sufficiently enter the above concave portions of the metal member during molding, and the adhesion between the metal member and the resin member can be enhanced. As a result, these airtightness can be enhanced.

[0017] As a result of the study by the present inventors, it was found that the airtightness can be enhanced by setting the ratio of the content of the aliphatic polyamide resin (B) ((B) / ((A)+(B))) to 0.15 or more.

[0018] Further, by setting the ratio of the content of the aliphatic polyamide resin (B) ((B) / ((A)+(B))) to 0.25 or less, more semi-aromatic polyamide resin (A) can be included, and as a result, it is possible to suppress the solidification of the polyamide resin composition from becoming too gentle. Therefore, it is possible to suppress a decrease in the mold release property from the mold during insert molding.

[0019] Hereinafter, based on the above findings, the configuration of the polyamide resin composition in the present embodiment will be described.

[0020] 1. Semi-aromatic polyamide resin (A) The semi-aromatic polyamide resin (A) is a polyamide resin having a melting point measured by a differential scanning calorimeter (DSC) of 290°C or higher and 340°C or lower. The method for measuring the melting point of the semi-aromatic polyamide resin (A) will be described later.

[0021] The semi-aromatic polyamide resin (A) is, for example, a polyamide resin containing a component unit (Aa) derived from a dicarboxylic acid and a component unit (Ab) derived from a diamine. Hereinafter, the polyamide resin containing the component unit (Aa) derived from a dicarboxylic acid and the component unit (Ab) derived from a diamine will be described.

[0022] (Component unit (Aa) derived from a dicarboxylic acid) The component unit (Aa) derived from a dicarboxylic acid preferably contains a component unit derived from an aromatic dicarboxylic acid, and more preferably contains a component unit derived from terephthalic acid.

[0023] The content of the component unit derived from terephthalic acid is preferably 20 mol% or more and 100 mol% or less, more preferably 30 mol% or more and 90 mol% or less, still more preferably 40 mol% or more and 85 mol% or less, and even more preferably 40 mol% or more and 65 mol% or less, based on the total number of moles of the component unit (Aa) derived from a dicarboxylic acid. When the above content is 20 mol% or more, the melting point of the semi-aromatic polyamide resin (A) increases, and the heat resistance of the resin member increases.

[0024] The component unit (Aa) derived from a dicarboxylic acid may contain a component unit derived from another dicarboxylic acid. Examples of other dicarboxylic acids include aliphatic dicarboxylic acids, alicyclic dicarboxylic acids, and aromatic dicarboxylic acids other than terephthalic acid. Among these, aliphatic dicarboxylic acids are preferred.

[0025] Examples of the above aliphatic dicarboxylic acids include aliphatic dicarboxylic acids having 4 to 20 carbon atoms. The number of carbon atoms is preferably 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.

[0026] The content of the component unit derived from the above aliphatic dicarboxylic acid is preferably 0 mol% or more and 60 mol% or less, more preferably 0 mol% or more and 45 mol% or less, based on the total number of moles of the component unit (Aa) derived from the dicarboxylic acid.

[0027] Examples of the above alicyclic dicarboxylic acids include cyclohexanedicarboxylic acid and its esters.

[0028] Examples of aromatic dicarboxylic acids other than terephthalic acid include isophthalic acid, 2-methylterephthalic acid, and naphthalenedicarboxylic acid.

[0029] The content of the component unit derived from an alicyclic dicarboxylic acid and an aromatic dicarboxylic acid other than terephthalic acid is preferably 20 mol% or more and 80 mol% or less, more preferably 25 mol% or more and 75 mol% or less, based on the total number of moles of the component unit (Aa) derived from the dicarboxylic acid.

[0030] (Component unit (Ab) derived from diamine) The component unit (Ab) derived from diamine includes, for example, a component unit derived from an aliphatic diamine having 4 to 15 carbon atoms, a component unit derived from an alicyclic diamine having 4 to 20 carbon atoms, and a component unit derived from an aromatic diamine.

[0031] The carbon number of the above aliphatic diamine is preferably 4 or more and 12 or less, more preferably 6 or more and 12 or less. Examples of the above aliphatic diamine include linear alkylenediamine and branched alkylenediamine.

[0032] Examples of the linear alkylene diamine include 1,4-diaminobutane, 1,6-diaminohexane, 1,7-diaminoheptane, 1,8-diaminooctane, 1,9-diaminononane, 1,10-diaminodecane, 1,11-diaminoundecane, 1,12-diaminododecane, and the like. Among these, 1,6-diaminohexane, 1,9-nonanediamine, and 1,10-diaminodecane are preferable, and 1,6-diaminohexane is more preferable. The linear alkylene diamine may contain only one kind or two or more kinds.

[0033] Examples of the branched-chain alkylene diamine 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, 2,4-dimethyl-1,8-diaminooctane, 3,4-dimethyl-1,8-diaminooctane, 4,5-dimethyl-1,8-diaminooctane, 2,2-dimethyl-1,8-diaminooctane, 3,3-dimethyl-1,8-diaminooctane, 4,4-dimethyl-1,8-diaminooctane, 3,3,5-trimethyl-1,8-diaminooctane, 2,4-diethyl-1,8-diaminooctane, and 5-methyl-1,9-diaminononane. Among these, 2-methyl-1,5-diaminopentane is preferred.

[0034] The content of the component unit derived from the aliphatic diamine is preferably 30 mol% or more and 100 mol% or less, more preferably 70 mol% or more and 100 mol% or less, based on the total number of moles of the component unit (Ab) derived from the diamine.

[0035] 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-bis(aminomethyl)norbornane, and 2,6-bis(aminomethyl)norbornane. Examples of the aromatic diamine include metaxylylenediamine.

[0036] Each structural unit of the semi-aromatic polyamide resin (A) and its ratio can be calculated from the charging ratio during the preparation of the semi-aromatic polyamide resin (A) or measured by the NMR method.

[0037] 1 In the case of 1H-NMR measurement, for example, a nuclear magnetic resonance apparatus (ECX400 type 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 observed nucleus is 1 1H (400 MHz), the sequence is a single pulse, the pulse width is 5.12 μs (45° pulse), the repetition time is 7.0 s, and the number of integrations is 500 times or more. The reference chemical shift is set to 0 ppm for the hydrogen of tetramethylsilane. However, the same result can also be obtained by setting the peak derived from the residual hydrogen of deuterated orthodichlorobenzene to 7.10 ppm as the reference value of the chemical shift. The 1 peaks of 1H, etc. derived from the functional group-containing compound can be assigned by a conventional method.

[0038] 13 In the case of 13C-NMR measurement, for example, a nuclear magnetic resonance apparatus (ECP500 type manufactured by JEOL Ltd.) is used as the measurement device, an orthodichlorobenzene / deuterated benzene (80 / 20 vol%) mixed solvent is used as the solvent, the measurement temperature is 120°C, and the observed nucleus is 13C (125 MHz), single-pulse proton decoupling, 45° pulse, repetition time of 5.5 seconds, number of accumulations of 10,000 or more, with a chemical shift reference value of 27.50 ppm. The assignment of various signals is carried out based on conventional methods, and quantification can be performed based on the integrated value of signal intensity.

[0039] Note that the component unit derived from the dicarboxylic acid of the semi-aromatic polyamide resin (A) may include a component unit derived from a biomass-derived dicarboxylic acid, and the component unit derived from the diamine may include a component unit derived from a biomass-derived diamine. Further, the semi-aromatic polyamide resin (A) may be a biomass-derived semi-aromatic polyamide resin (A) obtained by polymerizing a raw material group containing a biomass-derived raw material.

[0040] The semi-aromatic polyamide resin (A) is preferably a polyamide resin in which the component unit (Aa) derived from the dicarboxylic acid contains a component unit derived from terephthalic acid, and the component unit (Ab) derived from the diamine contains a component unit derived from 1,6-diaminohexane. According to the findings of the present inventors, the semi-aromatic polyamide resin (A) containing these component units has low compatibility with the aliphatic polyamide resin (B) containing a component unit derived from a component having 10 or more carbon atoms. Therefore, when these resins crystallize, since the crystal parts of individual molecules are arranged from a state where the molecules are mixed with each other, the crystallization rate can be sufficiently slowed down. As a result, when insert molding is performed, the rate at which the polyamide resin composition solidifies can be sufficiently slowed down, so that even when the mold temperature is low, the polyamide resin composition can sufficiently penetrate into the concave portions of the minute irregularities present on the surface of the metal member. Thereby, in the produced metal resin bonded body, the airtightness between the metal member and the resin member can be further enhanced.

[0041] Specific examples of the semi-aromatic polyamide resin (A) include polyamide 6T6I, polyamide 6T66, polyamide 6TDT, and the like.

[0042] The semi-aromatic polyamide resin (A) can be produced in the same manner as known polyamide resins. For example, it can be produced by polycondensing a dicarboxylic acid and a diamine in a homogeneous solution. Specifically, a lower condensate can be obtained by heating a dicarboxylic acid and a diamine in the presence of a catalyst as described in WO 03 / 085029, and then the melt of this lower condensate can be subjected to shear stress and polycondensed to produce it.

[0043] The content of the semi-aromatic polyamide resin (A) is preferably 20% by mass or more and 80% by mass or less, more preferably 25% by mass or more and 60% by mass or less, still more preferably 25% by mass or more and 50% by mass or less, based on the total mass of the polyamide resin composition. When the above content is 20% by mass or more, the mechanical strength and mold release property of the polyamide resin composition can be further enhanced. When the above content is 80% by mass or less, other components such as the aliphatic polyamide resin (B) described later can be sufficiently contained in the polyamide resin composition.

[0044] (Physical properties) The melting point of the semi-aromatic polyamide resin (A) measured by a differential scanning calorimeter (DSC) is preferably 280°C or higher and 340°C or lower, more preferably 290°C or higher and 335°C or lower.

[0045] The melting point of the semi-aromatic polyamide resin (A) can be adjusted to the above range by adjusting the composition of the semi-aromatic polyamide resin (A). For example, the melting point can be increased by increasing the content ratio of the component unit derived from terephthalic acid described later.

[0046] Further, the semi-aromatic polyamide resin (A) preferably has a glass transition temperature (Tg) measured by a differential scanning calorimeter (DSC) of more than 70°C and 145°C or less, more preferably 75°C or more and 125°C or less, and even more preferably 80°C or more and 100°C or less. When the glass transition temperature (Tg) exceeds 70°C, the temperature at which the molecular mobility becomes active in a high-temperature environment increases, so that the molecular mobility can be suppressed to further enhance the heat resistance of the polyamide resin composition and the molded article. Further, when the glass transition temperature (Tg) is 145°C or less, even when the mold temperature is low during molding, a decrease in the fluidity of the polyamide resin composition can be further suppressed, and the airtightness between the metal member and the resin member can be further improved.

[0047] The heat of fusion (ΔH) measured by differential scanning calorimetry (DSC) of the semi-aromatic polyamide resin (A) is preferably more than 5 J / g. The heat of fusion is an index of the crystallinity of the resin, and the larger the heat of fusion, the higher the crystallinity. When the heat of fusion (ΔH) of the semi-aromatic polyamide resin (A) exceeds 5 J / g, the crystallinity increases, so that the mechanical strength (such as flexural strength) of the obtained molded article can be increased.

[0048] The melting point and the heat of fusion (ΔH) of the semi-aromatic polyamide resin (A) can be measured using a differential scanning calorimeter (DSC220C type, manufactured by Seiko Instruments Inc.).

[0049] Specifically, about 5 mg of the semi-aromatic polyamide resin (A) is sealed in a measurement aluminum pan and heated from room temperature to 350°C at 10°C / min. In order to completely melt the resin, it is held at 350°C for 3 minutes, and then cooled to 30°C at 10°C / min. After leaving it at 30°C for 5 minutes, the second heating is performed from 30°C to 350°C at 10°C / min. The temperature (°C) of the endothermic peak in this second heating is defined as the melting point (Tm) of the semi-aromatic polyamide resin (A), and the inflection point corresponding to the glass transition is defined as the glass transition temperature (Tg). The heat of fusion (ΔH) is determined from the area of the endothermic peak during melting in the first heating process in accordance with JIS K7122.

[0050] The intrinsic viscosity [η] of the semi-aromatic polyamide resin (A) measured in 96.5% sulfuric acid at 25°C is preferably 0.9 dl / g or more and 1.2 dl / g or less, more preferably 1.0 dl / g or more and 1.2 dl / g or less, and particularly preferably 1.0 dl / g or more and 1.1 dl / g or less. When the intrinsic viscosity [η] of the semi-aromatic polyamide resin (A) is 0.9 dl / g or more, it is easy to sufficiently increase the mechanical strength (such as flexural strength) of the molded article, and when it is 1.2 dl / g or less, the fluidity during molding of the resin composition is less likely to be impaired. The intrinsic viscosity [η] can be adjusted by adjusting the molar ratio of the component unit (Aa) derived from dicarboxylic acid and the component unit (Ab) derived from diamine. Specifically, the closer the molar ratio of the component unit (Aa) derived from carboxylic acid and the component unit (Ab) derived from diamine is to 1:1, the higher the intrinsic viscosity can be increased. It can also be adjusted by the amount of end capping of the semi-aromatic polyamide resin (A), etc.

[0051] The intrinsic viscosity [η] of the semi-aromatic polyamide resin (A) can be measured as follows. Dissolve 0.5 g of the polyamide resin (A) in 50 ml of a 96.5% sulfuric acid solution to obtain a sample solution. Measure the flow-down seconds of the obtained solution under the condition of 25°C ± 0.05°C using an Ubbelohde viscometer, and calculate 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-down seconds of the sample solution (seconds) t0: Flow-down seconds of blank sulfuric acid (seconds) ηSP=(t - t0) / t0

[0052] 1-2. Aliphatic polyamide resin (B) As used herein, the "aliphatic polyamide resin" refers to a polyamide resin containing an amide bond [-NH-C(=O)-] and mainly containing repeating units that do not contain an aromatic ring. Here, "mainly containing" means that the content ratio of the repeating units containing an amide bond and not containing an aromatic ring is 80 mol% or more based on the total number of moles of the repeating units constituting the aliphatic polyamide resin. The content of the repeating units containing an amide bond and not containing an aromatic ring is preferably 90 mol% or more and 100 mol% or less based on the total number of moles of the repeating units constituting the aliphatic polyamide resin.

[0053] The aliphatic polyamide resin (B) contains at least one of a component unit derived from a dicarboxylic acid having 10 or more carbon atoms, a component unit derived from a diamine having 10 or more carbon atoms, a component unit derived from a lactam having 10 or more carbon atoms, and a component unit derived from an aminocarboxylic acid having 10 or more carbon atoms. In the present embodiment, it is preferable that these component units are included in the above-mentioned repeating units containing an amide bond and not containing an aromatic ring. Among these component units, a component unit derived from a lactam having 10 or more carbon atoms and a component unit derived from an aminocarboxylic acid having 10 or more carbon atoms are preferable. The number of carbon atoms in these component units is preferably 10 or more and 20 or less, and more preferably 11 or more and 18 or less.

[0054] The aliphatic polyamide resin (B) may be obtained by polycondensing a dicarboxylic acid and a diamine, or by ring-opening polymerization of a lactam, or by polycondensing an aminocarboxylic acid. That is, the aliphatic polyamide resin (B) may be composed of a component unit (Ba) derived from a dicarboxylic acid and a component unit (Bb) derived from a diamine, or may be composed of a component unit derived from a lactam, or may be composed of a component unit derived from an aminocarboxylic acid. Among these, it is preferable that the aliphatic polyamide resin (B) is composed of a component unit derived from a lactam and a component unit derived from an aminocarboxylic acid.

[0055] (Component unit (Ba) derived from dicarboxylic acid) The component unit (Ba) derived from dicarboxylic acid is a component unit derived from a dicarboxylic acid having 10 or more carbon atoms, and preferably includes a component unit derived from an aliphatic dicarboxylic acid having 10 or more carbon atoms. The number of carbon atoms of the above aliphatic dicarboxylic acid is preferably 10 or more and 20 or less, and more preferably 10 or more and 12 or less. The aliphatic dicarboxylic acid may be linear or branched-chain.

[0056] Examples of the aliphatic dicarboxylic acid include sebacic acid, dodecanedioic acid, tetradecanedioic acid, hexadecanedioic acid, octadecanedioic acid, eicosanedioic acid, and the like.

[0057] The content of the component unit derived from the above aliphatic dicarboxylic acid is preferably 80 mol% or more and 100 mol% or less, more preferably 85 mol% or more and 100 mol% or less, still more preferably 90 mol% or more and 100 mol% or less, and particularly preferably 100 mol% (the component unit (Ba) derived from dicarboxylic acid consists only of the component unit derived from an aliphatic dicarboxylic acid having 10 or more carbon atoms).

[0058] The component unit (Ba) derived from dicarboxylic acid may include a component unit derived from an alicyclic dicarboxylic acid. Examples of the above alicyclic dicarboxylic acid include 1,4-cyclohexanedicarboxylic acid and the like.

[0059] (Component unit (Bb) derived from diamine) The component unit (Bb) derived from diamine is a component unit derived from a diamine having 10 or more carbon atoms, and preferably includes a component unit derived from an aliphatic diamine having 10 or more carbon atoms. The number of carbon atoms of the above aliphatic diamine is preferably 10 or more and 20 or less, and more preferably 10 or more and 12 or less. The above aliphatic diamine may be linear or branched-chain.

[0060] Among the aliphatic diamines described for the semi-aromatic polyamide resin (A), those having 10 or more carbon atoms are included.

[0061] The content of the component unit derived from the aliphatic diamine is preferably 80 mol% or more and 100 mol% or less, more preferably 85 mol% or more and 100 mol% or less, still more preferably 90 mol% or more and 100 mol% or less, and particularly preferably 100 mol% (the component unit (Bb) derived from the diamine consists only of the component unit derived from an aliphatic diamine having 10 or more carbon atoms) with respect to the total number of moles of the component unit (Bb) derived from the diamine.

[0062] The component unit (Bb) derived from the diamine may contain a component unit derived from an alicyclic diamine. Examples of the alicyclic diamine include 1,4-cyclohexanediamine, 1,3-cyclohexanediamine, 1,3-cyclopentanediamine, and the like.

[0063] Each constitutional unit of the aliphatic polyamide resin (B) and its ratio can be calculated from the charging ratio during the preparation of the aliphatic polyamide resin (B) or measured by the NMR method. The NMR method can be the same as the method described for the semi-aromatic polyamide resin (A).

[0064] (Component unit derived from lactam) The component unit derived from lactam is a component unit derived from lactam having 10 or more carbon atoms. The number of carbon atoms of the lactam is preferably 10 or more and 14 or less, and more preferably 10 or more and 12 or less. Examples of the lactam include undecanolactam and laurolactam.

[0065] (Component unit derived from aminocarboxylic acid) The component unit derived from an aminocarboxylic acid is a component unit derived from an aminocarboxylic acid having 10 or more carbon atoms. Examples of aminocarboxylic acids include ω-aminocarboxylic acids and α,ω-aminocarboxylic acids. Among these, ω-aminocarboxylic acids are preferred.

[0066] An ω-aminocarboxylic acid is a linear or branched aliphatic carboxylic acid in which the ω-position is substituted with an amino group. The number of carbon atoms of the ω-aminocarboxylic acid is preferably 10 or more and 14 or less, and more preferably 10 or more and 12 or less. Examples of ω-aminocarboxylic acids include 11-aminoundecanoic acid and 12-aminododecanoic acid.

[0067] The aliphatic polyamide resin (B) is, for example, a polyamide resin containing a repeating unit having 10 or more consecutive carbon atoms, a polyamide resin having 9 or more carbon atoms bonded per amide group, and a polyamide resin having 9 or more carbon atoms in the hydrocarbon group bonded between two adjacent amide groups.

[0068] Specific examples of the aliphatic polyamide resin (B) include polyamide 10, polyamide 11, polyamide 12, polyamide 610, and the like.

[0069] The aliphatic polyamide resin (B) may be an aliphatic polyamide resin (B) derived from biomass, which is obtained by polymerizing a raw material group containing a raw material derived from biomass.

[0070] The content of the aliphatic polyamide resin (B) is preferably 5% by mass or more and 20% by mass or less, and more preferably 7% by mass or more and 18% by mass or less with respect to the total mass of the polyamide resin composition. When the above content is 5% by mass or more, even when the mold temperature is low, the decrease in the fluidity of the polyamide resin composition can be more suppressed, and the airtightness between the metal member and the resin member can be further enhanced.

[0071] The ratio of the content of the aliphatic polyamide resin (B) to the total mass of the semi-aromatic polyamide resin (A) and the aliphatic polyamide resin (B) ((B) / ((A)+(B))) is 0.15 or more and 0.25 or less, preferably 0.17 or more and 0.22 or less.

[0072] (Physical properties) The aliphatic polyamide resin (B) may be a polyamide resin with a melting point observable or a polyamide resin without an observable melting point, but it is preferably a polyamide resin with an observable melting point. The melting point of the aliphatic polyamide resin (B) measured by a differential scanning calorimeter (DSC) is preferably 200°C or lower, more preferably 190°C or lower, and even more preferably 180°C or lower. When the melting point is 200°C or lower, even when the mold temperature is low, the decrease in the fluidity of the polyamide resin composition can be more suppressed, and the airtightness between the metal member and the resin member can be further enhanced. The lower limit of the melting point of the aliphatic polyamide resin (B) is not particularly limited, but for example, it is 80°C, preferably 120°C, more preferably 150°C, and even more preferably 170°C.

[0073] Also, the glass transition temperature (Tg) of the aliphatic polyamide resin (B) measured by a differential scanning calorimeter (DSC) is preferably 70°C or lower, more preferably 60°C or lower. When the glass transition temperature is 70°C or lower, even when the mold temperature is low, the decrease in the fluidity of the polyamide resin composition can be more suppressed, and the airtightness between the metal member and the resin member can be further enhanced. The lower limit of the glass transition temperature is not particularly limited, but for example, it is 25°C.

[0074] Further, the aliphatic polyamide resin (B) preferably has a crystallization temperature of less than 240°C, more preferably less than 200°C, and even more preferably less than 150°C. Thereby, even when the mold temperature is low, the crystallization of the polyamide resin composition can be further delayed, so that the polyamide resin composition can sufficiently enter the recesses on the surface of the metal member during molding. As a result, the airtightness between the resin member and the metal member can be further enhanced. The lower limit value of the above crystallization temperature is not particularly limited, but is, for example, 50°C.

[0075] The melting point and glass transition temperature of the aliphatic polyamide resin (B) can be measured by the same method as described for the semi-aromatic polyamide resin (A). Further, the crystallization temperature of the aliphatic polyamide resin (B) can be determined by taking the temperature (°C) of the exothermic peak during the cooling process in the above-described measurement method of the melting point and glass transition temperature as the crystallization temperature.

[0076] 1-3. Other Components The polyamide resin composition may contain other known components.

[0077] Examples of other components include polyolefin resins, nucleating agents, lubricants, reinforcing materials, flame retardants, flame retardant aids, styrene-based thermoplastic elastomers, drip inhibitors, halogen scavengers, colorants, heat stabilizers, corrosion resistance improvers, drip inhibitors, ion scavengers, elastomers (rubbers), antistatic agents, mold release agents, antioxidants (such as phenols, amines, sulfurs, and phosphorus), heat stabilizers other than the above (such as lactone compounds, vitamin E, and hydroquinones), light stabilizers (such as benzotriazoles, triazines, benzophenones, benzoates, hindered amines, and oxanilides), and other polyamide resins (polyamide resins other than the semi-aromatic polyamide resin (A) and the aliphatic polyamide resin (B)).

[0078] Examples of polyolefin resins include ethylene polymers, propylene polymers, and butene polymers, as well as copolymers of these olefins (e.g., ethylene·α-olefin copolymers). Among these, an ethylene polymer is preferred.

[0079] Examples of α-olefins 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, and the like. Among these, propylene, 1-butene, 1-hexene, 4-methyl-1-pentene, and 1-octene are preferred.

[0080] The polyolefin resin preferably includes a modified polyolefin resin. Specifically, the polyolefin resin preferably includes a modified polyolefin resin having a polyolefin unit and a functional group structural unit. The modified polyolefin resin can be obtained by subjecting the polyolefin resin before modification to a modification reaction using a compound containing a functional group structural unit.

[0081] Examples of the above functional group structural units include functional groups containing heteroatoms. Examples of functional groups containing heteroatoms include carboxylic acid groups (including carboxylic anhydride groups), ester groups, ether groups, aldehyde groups, and ketone groups. Among these, carboxylic acid groups (including carboxylic anhydride groups) are preferred. That is, the modified polyolefin resin is preferably modified with an unsaturated carboxylic acid or a derivative thereof.

[0082] 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 anhydride group include dicarboxylic acid anhydrides having an α,β-unsaturated bond such as maleic anhydride, itaconic anhydride, and phthalic anhydride. Among these, maleic anhydride is preferred.

[0083] The content (modification amount) of the functional group structural unit of the modified polyolefin resin 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 the functional group structural unit is within the above range, the impact resistance and elongation rate of the resin composition are likely to increase.

[0084] The content (modification amount) of the functional group structural unit of the modified polyolefin resin can be calculated from the charging ratio during the preparation of the modified polyolefin resin or measured by the NMR method. For the NMR method, the same method as described for the polyamide resin (A) can be used.

[0085] The modified polyolefin resin is obtained by graft-modifying the polyolefin resin before modification with a compound containing a functional group structural unit.

[0086] The 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 for graft copolymerization, or by a solution modification method in which the polyolefin resin before modification is dissolved in a solvent and a graft monomer is added for graft copolymerization. In any case, in order to efficiently graft copolymerize the graft monomer, it is preferable to carry out the reaction in the presence of a radical initiator.

[0087] The content of the polyolefin resin is 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 with respect to the total mass of the polyamide resin composition.

[0088] (Nucleating agent) The nucleating agent can promote the crystallization of the semi-aromatic polyamide resin (A1) and the semi-aromatic polyamide resin (A2). Therefore, the tensile strength and elastic modulus of the molded body can be further increased.

[0089] Examples of the nucleating agent include metal salt-based compounds including sodium 2,2-methylenebis(4,6-di-t-butylphenyl)phosphate, aluminum tris(pt-butylbenzoate), and stearates, sorbitol-based compounds including bis(p-methylbenzylidene)sorbitol and bis(4-ethylbenzylidene)sorbitol, and inorganic substances including talc, calcium carbonate, and hydrotalcite. Among 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.

[0090] Talc generally contains hydrous magnesium silicate (SiO2: 58-64%, MgO: 28-32%, Al2O3: 0.5-5%, Fe2O3: 0.3-5%) as a main component. The average particle size of talc is not particularly limited, but is preferably 1-15 μm. When the average particle size of talc is within the above range, talc is easily dispersed in the polyamide resin (A) without impairing the fluidity of the polyamide resin composition. From the same viewpoint, the average particle size of talc is more preferably 1-7.5 μm. The average particle size of talc can be measured by a laser diffraction method, for example, a laser diffraction method using a Shimadzu particle size distribution analyzer (SALD-2000A type) manufactured by Shimadzu Corporation.

[0091] The content of the nucleating agent is preferably 0.10% by mass or more and 5.00% by mass or less, and more preferably 0.10% by mass or more and 3.00% by mass or less, based on 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 increased sufficiently, and sufficient mechanical strength is easily obtained.

[0092] (lubricant) The lubricant enhances 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.

[0093] The oxycarboxylic acid constituting the above metal oxycarboxylate may be an aliphatic oxycarboxylic acid or an aromatic oxycarboxylic acid. Examples of the above aliphatic oxycarboxylic acids include aliphatic oxycarboxylic acids having 10 to 30 carbon atoms such as α-hydroxymyristic acid, α-hydroxypalmitic acid, α-hydroxystearic acid, α-hydroxyeicosanoic acid, α-hydroxydocosanoic acid, α-hydroxytetraeicosanoic acid, α-hydroxyhexaeicosanoic acid, α-hydroxyoctaeicosanoic acid, α-hydroxytriacontanoic acid, β-hydroxymyristic acid, 10-hydroxydecanoic acid, 15-hydroxypentadecanoic acid, 16-hydroxyhexadecanoic acid, 12-hydroxystearic acid, and ricinoleic acid. Examples of the above aromatic oxycarboxylic acids include salicylic acid, m-hydroxybenzoic acid, p-hydroxybenzoic acid, gallic acid, mandelic acid, and tropic acid, etc.

[0094] Examples of the metal constituting the above metal oxycarboxylate include alkali metals such as lithium, and alkaline earth metals such as magnesium, calcium, and barium.

[0095] Among these, the above metal oxycarboxylate is preferably a metal salt of 12-hydroxystearic acid, and more preferably magnesium 12-hydroxystearate and calcium 12-hydroxystearate.

[0096] Examples of the higher fatty acid constituting the above higher fatty acid metal salt include higher fatty acids having 15 to 30 carbon atoms such as stearic acid, oleic acid, behenic acid, docosanoic acid, and montanic acid.

[0097] Examples of the metal constituting the above higher fatty acid metal salt include calcium, magnesium, barium, lithium, aluminum, zinc, sodium, and potassium, etc.

[0098] Among these, the above-mentioned metal salts of higher fatty acids are preferably calcium stearate, magnesium stearate, barium stearate, calcium behenate, sodium montanate, and calcium montanate.

[0099] The content of the lubricant is preferably 0.01% by mass or more and 1.30% by mass or less based on the total mass of the polyamide resin composition. When the content of the lubricant is 0.01% by mass or more, the fluidity during molding is likely to increase, and the appearance of the resulting molded product is likely to improve. When the content of the lubricant is 1.30% by mass or less, it is difficult for gases generated by the decomposition of the lubricant to be generated during molding, and the appearance of the product is likely to be good.

[0100] (Reinforcing material) The reinforcing material may be an inorganic filler. Examples of the reinforcing material include fibrous reinforcing materials such as glass fiber, wollastonite, potassium titanate whisker, calcium carbonate whisker, aluminum borate whisker, magnesium sulfate whisker, zinc oxide whisker, milled fiber and cut fiber, and particulate reinforcing materials. Among these, one kind may be used alone, or two or more kinds may be used in combination. Among them, wollastonite, glass fiber, and potassium titanate whisker are preferable, and wollastonite and glass fiber are more preferable because they can easily increase the mechanical strength of the resin member.

[0101] From the viewpoints of the moldability of the polyamide resin composition and the mechanical strength and heat resistance of the resulting resin member, the average fiber length of the fibrous reinforcing material is preferably 1 μm or more and 20 mm or less, and more preferably 5 μm or more and 10 mm or less.

[0102] The cross-sectional shape of the fibrous reinforcing material may be circular or non-circular, but from the viewpoint of increasing the tensile strength of the molded body, it is preferably circular. When the molded body has a thick portion, fibers are likely to be oriented in the thickness direction of the thick portion, so circular shapes can exhibit a better reinforcing effect (the effect of increasing the tensile strength of the molded body) against cracks generated inside the thick portion. The above cross-sectional shape can be confirmed by observing with an optical microscope.

[0103] The average fiber length and average fiber diameter of the fibrous reinforcing material can be measured by the following method. 1) After dissolving the polyamide resin composition in a hexafluoroisopropanol / chloroform solution (0.1 / 0.9% by volume), the filtrate obtained by filtration is collected. 2) Disperse the filtrate obtained in 1) above in water, and measure the fiber length (Li) and fiber diameter (di) of any 300 fibers each with an optical microscope (magnification: 50 times). Let the number of fibers with a fiber length of Li be qi, and calculate the weight average length (Lw) based on the following formula, and use this as the average fiber length of the fibrous reinforcing material. Weight average length (Lw) = (Σqi × Li 2 ) / (Σqi × Li) Similarly, let the number of fibers with a fiber diameter of Di be ri, and calculate the weight average diameter (Dw) based on the following formula, and use this as the average fiber diameter of the fibrous reinforcing material. Weight average diameter (Dw) = (Σri × Di 2 ) / (Σri × Di)

[0104] The content of the reinforcing material is preferably 20% by mass or more and 50% by mass or less, and more preferably 25% by mass or more and 40% by mass or less, based on the total mass of the polyamide resin composition. When the above content is 20% by mass or more, the mechanical strength of the resin member can be increased. When the above content is 40% by mass or less, the fluidity of the polyamide resin composition during molding can be increased, and the polyamide resin composition can easily enter the minute recesses on the surface of the metal member. Thereby, the airtightness between the resin member and the metal member in the metal-resin bonded body can be further enhanced.

[0105] (Colorant) The colorant imparts a desired color tone to the molded article. The colorant is not particularly limited and may be a pigment. Examples of pigments include inorganic pigments such as carbon black, alumina, titanium oxide, chromium oxide, iron oxide, zinc oxide, barium sulfate, and organic pigments such as azo pigments, phthalocyanine pigments, quinacridone pigments, perylene pigments, anthraquinone pigments, thioindigo pigments, and indanthrene pigments.

[0106] The content of the colorant is preferably 0.01% by mass or more and 5.00% by mass or less, 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.

[0107] (Other polyamide resins) Examples of other polyamide resins include semi-aromatic polyamide resins 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. The semi-aromatic polyamide resin contained in the other polyamide resins preferably exhibits amorphous properties. Specific examples of the other polyamide resins include polyamide 6I6T.

[0108] 1-4. Physical properties of the polyamide resin composition For the polyamide resin composition, the difference between the melting point and the crystallization temperature of the polyamide resin composition measured by a differential scanning calorimeter (DSC) is preferably 26°C or more, more preferably 27°C or more, and even more preferably 28°C or more. When the difference between the melting point and the crystallization temperature is 26°C or more, the crystallization rate of the polyamide resin composition becomes sufficiently slower, so that the airtightness between the resin member and the metal member can be increased more sufficiently. The upper limit value of the difference between the melting point and the crystallization temperature is, for example, 50°C. The melting point and the crystallization temperature of the polyamide resin composition can be measured by the methods described for the semi-aromatic polyamide resin (A) and the aliphatic polyamide resin (B).

[0109] 1-5. Method for producing the polyamide resin composition The polyamide resin composition can be produced by mixing the above-mentioned semi-aromatic polyamide resin (A), aliphatic polyamide resin (B), and, if necessary, other components by a known resin kneading method, such as a method of mixing with a Henschel mixer, V blender, ribbon blender, or tumbler blender, or, after mixing, further melt-kneading with a single-screw extruder, multi-screw extruder, kneader, or Banbury mixer and then granulating or pulverizing. At this time, the melting temperature during melt-kneading is preferably not less than the melting point (Tm) + 10°C of the semi-aromatic polyamide resin (A1) and the semi-aromatic polyamide resin (A2), and not more than the melting point (Tm) + 20°C.

[0110] 2. Metal-resin bonded body The metal-resin bonded body according to this embodiment includes a metal member and a resin member containing the above-mentioned polyamide resin composition bonded to the surface of the metal member.

[0111] 2-1. Resin member The resin member contains the above-mentioned polyamide resin composition. The proportion of the polyamide resin composition in 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 in the total mass of the resin member is not particularly limited, but can be 100.00% by mass or less, may be 90.00% by mass or less, or may be 80.00% by mass or less.

[0112] 2-2. Metal member The material and shape of the metal member are not particularly limited as long as it is a metal member. For example, the material of the metal member can be iron, copper, nickel, gold, silver, platinum, cobalt, zinc, lead, tin, titanium, chromium, aluminum, magnesium, and manganese, or alloys such as stainless steel, brass, and phosphor bronze.

[0113] These materials can be selected according to the application of the metal-resin bonded body. For example, when thermal conductivity is required, aluminum, aluminum alloys, magnesium, magnesium alloys, copper, and copper alloys are preferred, and copper and copper alloys are more preferred. Also, when weight reduction and strength retention are required, aluminum, aluminum alloys, magnesium, and magnesium alloys are preferred.

[0114] The surface of the above metal member is preferably roughened. The method of roughening treatment is not particularly limited, and the surface may be roughened by chemical treatments such as immersion in a treatment liquid containing a base or an acid or etching, or physical treatments such as laser or blasting.

[0115] The center-to-center distance (pitch) of a plurality of convex portions formed by the roughening treatment on the surface of the roughened metal member is preferably 5 nm or more and 500 μm or less. When the center-to-center distance of the plurality of convex portions is 5 nm or more, the recesses between the convex portions are moderately large, so that the resin member can be sufficiently immersed in the recesses during bonding, and the bonding strength between the metal member and the resin member can be further improved. Also, when the center-to-center distance of the plurality of convex portions is 500 μm or less, the recesses do not become too large, so that the generation of gaps at the metal-resin interface of the metal-resin bonded body can be further suppressed, and the airtightness can be further enhanced. From the same viewpoint, the center-to-center distance of the plurality of convex portions is more preferably 5 μm or more and 250 μm or less. The center-to-center distance of the plurality of convex portions is the average value of the distances between the center of one convex portion and the center of the adjacent convex portion.

[0116] The center-to-center distance of the plurality of convex portions can be measured by removing the resin member from the metal-resin bonded body by mechanical peeling, solvent cleaning, etc., and observing and measuring the surface of the exposed metal member using an electron microscope, a laser microscope, or a surface roughness measuring device.

[0117] Specifically, when the center-to-center distance between a plurality of convex portions is less than 0.5 μm, it can be observed by an electron microscope. When the center-to-center distance between a plurality of convex portions is 0.5 μm or more, it can be observed by 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 arbitrary convex portions are selected, and the center-to-center distances of these convex portions are measured respectively. Then, after integrating all the measured values of the center-to-center distances of the convex portions, the result divided by 50 (the average value) is defined as the "center-to-center distance between a plurality of convex portions".

[0118] The average value of the ten-point height (Rz) at an evaluation length of 4 mm on the roughened surface of the metal member is not particularly limited, but is preferably more than 2 μm, more preferably greater than 2 μm and 50 μm or less, and even more preferably greater than 2.5 μm and 45 μm or less.

[0119] The average value of the ten-point height (Rz) can be measured in accordance with JIS B0601 (ISO 4287). Specifically, the ten-point height (Rz) on a total of six straight lines, namely, any three straight lines parallel to each other and any three straight lines perpendicular to them, is measured, and the average value of these is defined as the average value of Rz.

[0120] The average length (RSm) of the roughness curve elements on 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 enhancing the bonding strength, it is preferable that the center-to-center distance between a plurality of convex portions is less than 0.5 μm and the average length (RSm) of the roughness curve elements is 0.5 μm or more and 500 μm or less. The average length of the roughness curve elements can also be measured by JIS B0601 (ISO 4287) in the same manner as described above.

[0121] 3. Method for manufacturing a metal-resin bonded body The manufacturing method of the metal-resin composite is not particularly limited. For example, it includes: (1) a step of preparing a metal member; (2) a step of placing the metal member in a mold and injecting and filling the molten polyamide resin composition into the mold; and (3) a step of cooling the polyamide resin composition. The step (1) of preparing the metal member may include a step of roughening the surface of the metal member.

[0122] 3-1. Preparation of Metal Member First, prepare the above-mentioned metal member. 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.

[0123] The method for roughening the surface of the metal member is not particularly limited. For example, a method using laser processing, a method of immersing the metal member in an inorganic base aqueous solution such as NaOH or an inorganic acid aqueous solution such as HCl or HNO3, a method of treating the metal member by an anodizing method, a displacement crystallization method of etching with an acid-based etching agent (preferably an acid-based etching agent aqueous solution containing an inorganic acid, ferric ion, cupric ion, and optionally manganese ion, aluminum chloride hexahydrate, sodium chloride, etc.), a method of immersing the metal member in an aqueous solution such as hydrazine hydrate, ammonia, and a water-soluble amine compound, and a hot water treatment method can be used.

[0124] 3-2. Insert Molding Next, place the metal member in the mold and inject and fill the molten polyamide resin composition into the mold. Thereby, the softened or molten polyamide resin composition and the prepared metal member are joined.

[0125] Specifically, first, the prepared metal member is placed in the cavity part (space part) in the injection mold. Then, the polyamide resin composition is injection-molded into the cavity part of the mold so that at least a part of the polyamide resin composition contacts the metal member. Thereby, the injected and molten polyamide resin composition contacts the surface of the metal member. The temperature of the injection mold at this time may be any temperature that can melt the polyamide resin composition into a state suitable for injection molding, and is not particularly limited. For example, it can be 100 to 350 °C.

[0126] As the mold, known injection molds, such as molds for rapid heat cycle molding (RHCM, heat & cool molding) and core-back molds for foam molding, can be used.

[0127] 3-3. Cooling Thereafter, by cooling and solidifying the polyamide resin composition in contact with the surface of the metal member, a metal-resin bonded body in which a resin member containing the polyamide resin composition is bonded to the surface of the metal member can be obtained.

[0128] 4. Applications The above-described metal-resin bonded body is suitably used in various applications where the metal-resin bonded body is applied or the application is under consideration.

[0129] Examples of the above applications include vehicle structural parts, vehicle-mounted articles, housings of electronic devices, housings of household appliances, structural parts, mechanical parts, various automotive parts, electronic device parts, furniture, household goods for household use such as kitchen utensils, medical devices, parts of building materials, other structural parts, and exterior parts.

[0130] More specifically, examples of the above applications include, in the vehicle field, instrument panels, console boxes, door knobs, door trims, shift levers, pedals, glove boxes, bumpers, bonnets, fenders, trunks, doors, roofs, pillars, seat cushions, steering wheels, bus bars, terminals, motors, power conversion devices (inverters, converters), ECU boxes, electrical components, engine peripheral components, drive train and gear peripheral components, intake and exhaust system components, and cooling system components, etc. Also, as precision electronic components, connectors, relays, gears, etc. are included.

[0131] In addition, the above metal-resin bonded body combines the high thermal conductivity of the copper member and the heat-insulating properties of the resin member, and is used for component applications in devices that optimally design heat management. For example, it can also be used in various household appliances. Examples of the above applications include household appliances such as refrigerators, washing machines, vacuum cleaners, microwave ovens, air conditioners, lighting fixtures, electric kettles, televisions, clocks, ventilation fans, projectors, speakers, etc., and electronic information devices such as personal computers, mobile phones, smartphones, digital cameras, tablet PCs, portable music players, portable game consoles, chargers, and batteries.

[0132] Examples of other applications include components for lithium-ion secondary batteries and robots, etc.

[0133] For example, the above metal-resin bonded body can be used in a bus bar unit of a moving body (vehicle) such as an automobile.

[0134] Figure 1 is a schematic diagram showing an exemplary form of the above metal-resin bonded body as a bus bar unit. The bus bar unit 100 has a bus bar 110 which is a conductive metal member (for example, a copper-made metal member) and is a conductor for supplying current to each member, and a holding member 120 which is the above-described resin member and serves as a protection member for protecting the bus bar 110.

[0135] Of the surfaces of the bus bar 110, which is a metal member, the surface that contacts the holding member 120 is roughened, and the holding member 120, which is a resin member (a resin member including a molded body of a polyamide resin composition), is joined to the roughened surface.

[0136] The bus bar unit 100 can be used to electrically connect a motor of a moving body and an inverter that controls the power supplied to the motor by the bus bar 110.

[0137] FIG. 2 is a configuration diagram showing an exemplary configuration of a moving body (vehicle) having the bus bar unit 100. The moving body 200 includes a body 210, a power source 220 such as a secondary battery that supplies power for driving the body 210, and a drive unit 230 that drives the body 210 with the power supplied from the power source 220.

[0138] The drive unit 230 includes an inverter 232 that controls the power (current) from the power source 220, a motor 234 that rotates by being supplied with the power controlled by the inverter 232, and a bus bar unit 100 having a bus bar 110 that connects the inverter 232 and the motor 234. The motor 234 is housed in a motor case 236 together with a speed reducer 235 that converts the rotational speed obtained by the motor 234 into a rotational speed for driving the body 210. The bus bar unit 100 is attached to the motor case 236, and the bus bar 110 communicates from the inside to the outside of the motor case 236 via the bus bar unit 100.

[0139] Note that a coolant (coolant oil) for cooling the motor 234 is stored inside the motor case 236. Also, at the connection portion between the bus bar unit 100 and the motor case 236, an airtight process is performed by a sealing member such as an O-ring, thereby preventing the leakage of oil from the inside to the outside of the motor case 236.

[0140] By the way, in the conventional bus bar unit, oil may leak between the bus bar and the protective member due to the low airtightness between the bus bar and the resin protective member. In contrast, in the present embodiment, the holding member 120 made of a resin member including the molded body of the above-described polyamide resin composition is hermetically joined to the bus bar 110 which is a conductive metal member (for example, a copper metal member), so that oil leakage can be suppressed.

[0141] In addition, in FIG. 2, an example in which the moving body 200 is a vehicle such as an automobile is shown, but the moving body 200 is not particularly limited as long as it is an object that can move with a body and a drive unit. For example, in addition to vehicles such as automobiles, motorcycles, and electric bicycles, railway vehicles, ships, airplanes, drones, robots, etc. may be used as the moving body 200.

Example

[0142] Hereinafter, the present invention will be described with reference to examples. The scope of the present invention is not construed as being limited by the examples.

[0143] 1. Synthesis / Preparation of Materials 1-1. Synthesis of Semi-aromatic Polyamide Resin (A) <Polyamide Resin (A) (6TDT)> 1,6-diaminohexane 1312 g (11.3 mol), 2-methyl-1,5-pentanediamine 1312 g (11.3 mol), terephthalic acid 3655 g (22.0 mol), 5.5 g of sodium hypophosphite as a catalyst, and 640 ml of ion-exchanged water were charged into a 1-liter reactor. After nitrogen substitution, the reaction was carried out at 250 ° C and 35 kg / cm 2 for 1 hour. After 1 hour, the reaction product generated in this reactor was extracted into a receiver connected to this reactor and having a pressure set to about 10 kg / cm 2 lower, and a polyamide precursor having an intrinsic viscosity [η] of 0.15 dl / g was obtained. Next, after drying this polyamide precursor, it was melt-polymerized at a cylinder set temperature of 330 ° C using a twin-screw extruder to obtain polyamide resin (A).

[0144] The intrinsic viscosity [η] of the obtained polyamide resin (A) was 0.9 dl / g, the melting point (Tm) was 300 °C, the glass transition temperature (Tg) was 140 °C, and the heat of fusion (ΔH) was 45 J / g. Further, the composition of the obtained polyamide resin (A-2) was such that the content of the component unit derived from terephthalic acid in the component units derived from dicarboxylic acid was 100 mol%, and the content of the component unit derived from 1,6-diaminohexane in the component units derived from diamine was 50 mol%, and the content of the component unit derived from 2-methyl-1,5-pentanediamine was 50 mol%.

[0145] 1-2. Aliphatic polyamide resin (B) Nylon 12 was used. (Melting point: 180 °C, crystallization temperature: 140 °C, glass transition temperature: 50 °C)

[0146] 1-3. Other components 1-3-1. Synthesis of modified polyolefin resin 0.63 mg of bis(1,3-dimethylcyclopentadienyl)zirconium dichloride was placed in a glass flask sufficiently purged with nitrogen, and further 1.57 ml of a toluene solution of methylaminoxane (Al; 0.13 mmol / liter) and 2.43 ml of toluene were added to obtain a catalyst solution. Next, 912 ml of hexane and 320 ml of 1-butene were introduced into a 2-liter stainless steel autoclave sufficiently 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 pressured into the system with ethylene to initiate the polymerization reaction. By continuously supplying ethylene, the total pressure was maintained at 8.0 kg / cm2-G, and polymerization was carried out at 80 °C for 30 minutes. After introducing a small amount of ethanol into the system to stop the polymerization, unreacted ethylene was purged. The obtained solution was dropped into a large excess of methanol to precipitate a white solid. This white solid was recovered by filtration and dried under reduced pressure overnight to obtain a white solid (ethylene·1-butene copolymer).

[0147] The ethylene content of the above ethylene-1-butene copolymer was 81 mol%. The density was 0.860 g / cm 3 and the MFR (ASTM D 1238, 190 °C, 2.16 kg load) was 0.5 g / 10 min, and the melting point was 35 °C.

[0148] To 100 parts by mass of the obtained ethylene-1-butene copolymer, 1.0 part by mass of maleic anhydride and 0.04 part by mass of a peroxide (Perhexyne 25B, manufactured by NOF Corporation) were mixed. The obtained mixture was melt graft-modified with a twin-screw extruder set at 230 °C to obtain a modified polyolefin resin.

[0149] The content (modification amount) of the component unit derived from maleic anhydride in the obtained modified polyolefin resin was 0.8% by mass. The density was 0.866 g / cm 3 and the MFR was 0.27 g / 10 min.

[0150] 1-3-2. Colorant A masterbatch containing a pigment was used as the colorant.

[0151] 1-3-3. Lubricant Sodium montanate was used.

[0152] 1-3-4. Nucleating agent Talc (average particle size 6 μm) was used.

[0153] 1-3-5. Reinforcing agent Glass fiber (manufactured by Owens Corning, FT2A) was used.

[0154] 2. Measurement The physical properties of each of the above resins were measured by the following methods.

[0155] <Melting point (Tm), glass transition temperature (Tg)> The melting point (Tm) and glass transition temperature (Tg) of the semi-aromatic polyamide resin (A) and the aliphatic polyamide resin (B) were measured using differential scanning calorimetry (DSC220C type, manufactured by Seiko Instruments Inc.). Specifically, approximately 5 mg of the polyamide resin was sealed in a measurement aluminum pan and set for differential scanning calorimetry. Then, it was heated from room temperature to 350 °C at 10 °C / min. In order to completely melt the resin, it was held at 350 °C for 3 minutes, and then cooled to 30 °C at 10 °C / min. After leaving it at 30 °C for 5 minutes, the second heating was carried out from 30 °C to 350 °C at 10 °C / min. The temperature (°C) of the endothermic peak in this second heating was defined as the melting point (Tm) of the polyamide resin, and the inflection point corresponding to the glass transition was defined as the glass transition temperature (Tg). Also, for the aliphatic polyamide resin (B), the crystallization temperature was defined as the temperature (°C) of the exothermic peak in the cooling process.

[0156] <Heat of fusion (ΔH)> The heat of fusion (ΔH) of the semi-aromatic polyamide resin (A) was determined from the area of the exothermic peak of crystallization in the first heating process in accordance with JIS K 7122 (2012).

[0157] <Limiting viscosity [η]> The limiting viscosity [η] of the semi-aromatic polyamide resin (A) was measured by dissolving 0.5 g of the polyamide resin in 50 ml of a 96.5% sulfuric acid solution, measuring the flow-down seconds of the resulting solution under the condition of 25 °C ± 0.05 °C using an Ubbelohde viscometer, and calculating it based on the formula: "[η]=ηSP / (C(1 + 0.205ηSP))". [η]: Limiting viscosity (dl / g) ηSP: Specific viscosity C: Sample concentration (g / dl) t: Flow-down seconds of the sample solution (seconds) t0: Flow-down seconds of the blank sulfuric acid (seconds) ηSP=(t - t0) / t0

[0158] <Degree of modification> The content (degree of modification) (mass%) of the component unit derived from maleic anhydride in the modified polyolefin resin was measured by the NMR method. The measurement conditions are as follows. Measurement device: Nuclear magnetic resonance device (ECP500 type, manufactured by JEOL Ltd.) Observed nucleus: 13 C (125 MHz) Sequence: Single pulse proton decoupling Pulse width: 4.7 μs (45° pulse) Repetition time: 5.5 s Number of integrations: 10,000 times or more Solvent: Ortho-dichlorobenzene / deuterated benzene (volume ratio: 80 / 20) mixed solvent Sample concentration: 55 mg / 0.6 mL Measurement temperature: 120 °C Reference value of chemical shift: 27.50 ppm

[0159] <Density> The density of the modified polyolefin resin was measured at 23 °C in accordance with JIS K7112:1999 using a density gradient column.

[0160] <mfr> The MFR was measured in accordance with ASTM D1238 (2023) at a load of 2.16 kg at 190 °C.

[0161] 3. Preparation of polyamide resin composition The above materials were mixed in a tumbler blender at the composition ratios (unit: parts by mass) shown in Table 1, and melt-kneaded under cylinder temperature conditions of 300 to 335 °C using a 30 mmφ vented twin-screw extruder. Then, the kneaded product was extruded into strands and cooled in a water tank. Then, the strands were taken up by a pelletizer and cut to obtain pellet-shaped polyamide resin compositions 1 to 3.

[0162] In the same manner as the measurement methods for the melting point and crystallization temperature of the semi-aromatic polyamide resin (A) and the aliphatic polyamide resin (B), the melting point (Tm) and the crystallization temperature (Tc) of the polyamide resin composition were measured, and the temperature difference (Tm - Tc) was determined.

[0163] 4. Preparation of metal-resin bonded body <Preparation of roughened copper member> A copper alloy plate (thickness 2 mm) of alloy number C1100 defined in JIS H3100 (2012) was cut into a length of 45 mm and a width of 18 mm to prepare a copper member. The copper member was immersed in a 2.6 mass% sodium hydroxide aqueous solution (55 °C) containing 0.16 mass% sodium gluconate for 5 minutes while performing ultrasonic cleaning, and then washed with water (20 seconds × 3 times) to perform a degreasing process.

[0164] Next, the copper member was immersed in a 0.002 mass% sodium hydroxide aqueous solution (35 °C) containing 0.1 mass% benzotriazole and 0.3 mass% 2-isopropoxyethanol for 20 seconds, and then washed with water (20 seconds × 3 times) to remove the coating on the surface of the metal material.

[0165] 9.5 mass% sulfuric acid, 2 mass% hydrogen peroxide, 1.1 mass% benzotriazole, 0.024 mass% glycine, and 0.00225 mass% sodium chloride were dissolved in water to prepare an etching solution. A copper member was immersed in the etching solution (40 °C) for 3 minutes and then washed with water (20 seconds × 3 times), thereby forming a fine structure on the surface of the copper member. When the pH of the etching solution at 25 °C was measured using a pH meter "D-71" manufactured by Horiba, Ltd., it was 0.3.

[0166] While performing ultrasonic cleaning, a metal material was immersed in water (room temperature) for 3 minutes to remove smut. Subsequently, the metal material was dried at 80 °C for 20 minutes. Through the above steps, a roughened copper member was fabricated.

[0167] <Fabrication of Metal-Resin Bonded Body> The roughened copper member was placed in a small dumbbell metal insert mold attached to an injection molding machine (J55-AD, manufactured by Nippon Steel & Sumitomo Metal Corporation). Next, each polyamide resin composition was injected into the mold under the conditions of a cylinder temperature of 335 °C, a mold temperature (MT) of 170 °C, a primary injection pressure of 90 MPa, a holding pressure of 80 MPa, and an injection speed of 25 mm / second to fill the mold. Thereby, a test piece A in which a resin member made of polyamide resin was joined to the surface of the copper member was fabricated. The joint area between the copper member and the resin member of this test piece was 50 mm 2 It was.

[0168] A test piece B of the metal-resin bonded body was fabricated in the same manner except that the mold temperature (MT) was changed to 150 °C.

[0169] 4. Evaluation <Airtightness> The helium leak tightness of the fabricated test pieces was evaluated by a method conforming to ISO19095. Specifically, the above test pieces were set in a dedicated jig capable of sealing, He gas was applied to the sealed space at a pressure of 0.1 MPa, and the He gas passing through the test pieces was measured by the sniffer method using a He gas detector (HELEN M-222LD, manufactured by Canon Anelva Corporation). Based on the detected He gas flow rate (leakage amount) 5 minutes after the start of detection, the airtightness was evaluated according to the following criteria. ○ The detected He gas flow rate is 1.0×10 -6 Pa·m 3 / s or less × The detected He gas flow rate is more than 1.0×10 -6 Pa·m 3 / s

[0170] Table 1 shows the compositions and evaluation results of each polyamide resin composition. The numerical values in the composition of Table 1 represent parts by mass.

[0171]

Table 1

[0172] From the results of Polyamide Resin Composition 1, when the ratio of the content of the aliphatic polyamide resin (B) to the total mass of the semi-aromatic polyamide resin (A) and the aliphatic polyamide resin (B) is 0.15 or more and 0.25 or less, even when the mold temperature is low, the airtightness between the metal member and the resin member comparable to that when the mold temperature is high can be obtained.

Industrial Applicability

[0173] The polyamide resin composition of the present invention is useful, for example, for insert molded products (for example, automotive parts).

Explanation of Symbols

[0174] 100 Busbar Unit 110 Busbar 120 Holding Member< / mfr>

Claims

1. A polyamide resin composition for bonding to a metal member, comprising: A semi-aromatic polyamide resin (A) having a melting point measured by differential scanning calorimetry (DSC) of 290°C or higher and 340°C or lower; An aliphatic polyamide resin (B) containing at least one of a component unit derived from a dicarboxylic acid having 10 or more carbon atoms, a component unit derived from a diamine having 10 or more carbon atoms, a component unit derived from a lactam having 10 or more carbon atoms, and a component unit derived from an aminocarboxylic acid having 10 or more carbon atoms; and The ratio of the content of the aliphatic polyamide resin (B) to the total mass of the semi-aromatic polyamide resin (A) and the aliphatic polyamide resin (B), ((B) / ((A)+(B))), is 0.15 or more and 0.25 or less. A polyamide resin composition.

2. The semi-aromatic polyamide resin (A) contains a component unit (Aa) derived from a dicarboxylic acid and a component unit (Ab) derived from a diamine. The component unit (Aa) derived from the dicarboxylic acid contains a component unit derived from terephthalic acid. The component unit (Ab) derived from the diamine contains a component unit derived from 1,6-diaminohexane. The polyamide resin composition according to Claim 1.

3. The aliphatic polyamide resin (B) contains either a component unit derived from a lactam having 10 or more carbon atoms or a component unit derived from an aminocarboxylic acid having 10 or more carbon atoms. The polyamide resin composition according to Claim 1.

4. The melting point of the aliphatic polyamide resin (B) is 200°C or lower. The polyamide resin composition according to Claim 1.

5. The glass transition temperature of the aliphatic polyamide resin (B) is 70°C or lower. The polyamide resin composition according to Claim 1.

6. The polyamide resin composition further contains a reinforcing material having a content of 20% by mass or more and 40% by mass or less based on the total mass of the polyamide resin composition. The polyamide resin composition according to Claim 1.

7. The difference between the melting point and the crystallization temperature of the polyamide resin composition measured by differential scanning calorimeter (DSC) is 26°C or higher. The polyamide resin composition according to Claim 1.

8. A metal member and A resin member including the polyamide resin composition according to any one of Claims 1 to 7 bonded to the surface of the metal member. A metal-resin bonded body.

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