Metal-resin composite, method for producing the same, and polyamide resin composition

Abstract

To provide a metal-resin composite that is manufactured by injection molding a polyamide resin composition, and is less likely to lose bonding strength even when applying low mold temperature compared to the metal-resin composite manufactured at high mold temperature.SOLUTION: In the metal-resin composite having a metal member and a resin member bonded to a surface of the metal member, the resin member includes a polyamide resin (A) having a glass transition temperature Tg of 80°C or higher and 160°C or lower as measured by a differential scanning calorimeter (DSC), and a polyamide resin (B) having a glass transition temperature Tg of 70°C or less as measured by the differential scanning calorimeter (DSC).SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to a metal-resin composite, a method for producing the same, and a polyamide resin composition.

Background Art

[0002] From the viewpoint of weight reduction of various components, the use of resin as a substitute for metal has been studied. However, it is often difficult to replace all metal parts with resin. For such cases, the use of a metal-resin composite formed by joining a metal molded body and a resin molded body has been studied.

[0003] For example, Patent Document 1 describes that a polyamide resin composition containing various polyamide resins is injected and joined to an aluminum alloy having unevenness or pores formed on its surface by immersion treatment in an erosive aqueous solution or anodization treatment. Further, Patent Document 2 describes that a polyamide resin composition containing an aromatic polyamide having specific physical properties is well joined to an aluminum member.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0005] As described in Patent Document 1 and Patent Document 2, various methods for joining a polyamide resin composition to a metal such as aluminum have been studied. Further, Patent Document 2 describes that a metal-resin composite having good joining properties with an aluminum member was obtained using a specific aromatic polyamide.

[0006] Incidentally, the aromatic polyamide resin as described in Patent Document 2 has a high melting point. Therefore, when producing the metal resin composite described in Patent Document 2, the mold temperature has to be raised to a high temperature during joining by injection molding. On the other hand, from the viewpoint of reducing the manufacturing cost of the metal resin composite, it is required to lower the heating temperature of the mold during manufacturing.

[0007] However, according to the findings of the present inventors, when manufacturing a metal resin composite by low-injection molding a polyamide resin composition with a low mold temperature, compared with the case of manufacturing a metal resin composite with a high mold temperature, the bonding strength between the polyamide resin composition and the metal member is significantly reduced.

[0008] The present invention has been made in view of the above problems, and even when manufacturing a metal resin composite by injection molding a polyamide resin composition with a low mold temperature, compared with the case of manufacturing a metal resin composite with a high mold temperature, it is an object of the present invention to provide a polyamide resin composition in which the bonding strength is less likely to decrease, a method for manufacturing a metal resin composite using the polyamide resin composition, and the manufactured metal resin composite.

Means for Solving the Problems

[0009] A metal resin composite having a metal member and a resin member joined to the surface of the metal member according to one aspect of the present invention for solving the above problems, wherein the resin member contains a polyamide resin (A) having a glass transition temperature Tg measured by a differential scanning calorimeter (DSC) of 80°C or higher and 180°C or lower, and a polyamide resin (B) having a glass transition temperature Tg measured by a differential scanning calorimeter (DSC) of 70°C or lower, and contains a polyamide resin composition.

[0010] A method for manufacturing a metal-resin composite according to another aspect of the present invention for solving the above problems includes a step of preparing a metal member, and a step of injecting and solidifying a molten polyamide resin composition onto the surface of the metal member. The polyamide resin composition includes a polyamide resin (A) having a glass transition temperature Tg measured by a differential scanning calorimeter (DSC) of 80°C or higher and 180°C or lower, and a polyamide resin (B) having a glass transition temperature Tg measured by a differential scanning calorimeter (DSC) of 70°C or lower.

[0011] A polyamide resin composition for bonding to a metal member according to another aspect of the present invention for solving the above problems includes a polyamide resin (A) having a glass transition temperature Tg measured by a differential scanning calorimeter (DSC) of 80°C or higher and 180°C or lower, and a polyamide resin (B) having a glass transition temperature Tg measured by a differential scanning calorimeter (DSC) of 70°C or lower.

Advantages of the Invention

[0012] According to the present invention, there are provided a polyamide resin composition in which the bonding strength is less likely to decrease even when a metal-resin composite is manufactured by injection molding a polyamide resin composition with a low mold temperature as compared with when a metal-resin composite is manufactured with a high mold temperature, a method for manufacturing a metal-resin composite using the polyamide resin composition, and the manufactured metal-resin composite.

Embodiments for Carrying Out the Invention

[0013] 1. Metal-Resin Bonded Body The first embodiment of the present invention relates to a metal-resin bonded body having a metal member and a resin member bonded to the surface of the metal member.

[0014] 1-1. Metal Member The metal member may be any one obtained by shaping metal to give a predetermined shape.

[0015] The metal type of the metal member is not particularly limited, and aluminum, iron, copper, magnesium, tin, nickel, zinc, and alloys thereof can be used. Among these, aluminum, copper, and alloys thereof are preferred. The entire metal member may be formed of these metal types, but it suffices if these metal types are included at least in the joint surface with the polyamide resin composition.

[0016] The shape of the metal member is not particularly limited and can be arbitrarily determined according to the use of the metal resin composite. Examples of the shape of the metal member include a flat plate shape, a curved plate shape, a rod shape, a cylindrical shape, and an irregular shape. However, it is preferable that the joint surface of the metal member with the polyamide resin composition is planar such as a flat surface or a curved surface. The metal member can be produced by subjecting the metal as the material to plastic working including cutting and pressing, or to finishing working including punching, cutting, polishing, and electrical discharge machining.

[0017] It is preferable that the joint surface of the metal member with the polyamide resin composition is roughened. The method of the roughening treatment is not particularly limited, and the surface may be roughened by chemical treatment such as immersion in a treatment liquid containing a base or an acid or etching, or by physical treatment such as laser or blast.

[0018] It is preferable that 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 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 appropriately large, so that the resin composition can be sufficiently infiltrated into the recesses during joining, and the joining strength between the metal member and the resin member can be further improved. Further, 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 composite can be more suppressed and the adhesion 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.

[0019] The center-to-center distance between the plurality of convex portions can be measured by mechanically peeling off the resin member from the metal-resin bonded body, cleaning with a solvent, etc., and observing the surface of the exposed metal member using an electron microscope, a laser microscope, or a surface roughness measuring device.

[0020] Specifically, when the center-to-center distance between the plurality of convex portions is less than 0.5 μm, it can be observed with an electron microscope, and when the center-to-center distance between the plurality of convex portions is 0.5 μm or more, it can be observed with a laser microscope or a surface roughness measuring device. For example, in a photograph of the surface of the metal member taken with an electron microscope or a laser microscope, 50 arbitrary convex portions are selected, and the center-to-center distances of those convex portions are measured respectively. Then, after integrating all the measured values of the center-to-center distances of the convex portions and dividing by 50 (averaging), the result is taken as the "center-to-center distance between the plurality of convex portions".

[0021] 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 more than 2 μm and 50 μm or less, and even more preferably more than 2.5 μm and 45 μm or less.

[0022] 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 taken as the average value of Rz.

[0023] 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 the 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 in accordance with JIS B0601 (ISO 4287) as described above.

[0024] 1-2. Resin member The resin member is a member including a molded body of a polyamide resin composition. The polyamide resin composition includes a polyamide resin (A) having a glass transition temperature (Tg) measured by a differential scanning calorimeter (DSC) of 80°C or higher and 180°C or lower, and a polyamide resin (B) having a glass transition temperature (Tg) measured by a differential scanning calorimeter (DSC) of 70°C or lower.

[0025] The polyamide resin composition is a resin composition in which the main components of the resin components are polyamide resin (A) and polyamide resin (B). The main component means that the proportion of polyamide resin (A) and polyamide resin (B) in the resin components is 50% by mass or more. The proportion of polyamide resin (A) and polyamide resin (B) in the resin components is preferably 60% by mass or more, more preferably 70% by mass or more. The upper limit of the proportion of polyamide resin (A) in the resin components is not particularly limited, but can be 100% by mass or less, may be 90% by mass or less, or may be 80% by mass or less.

[0026] 1-2-1. Polyamide resin (A) The polyamide resin (A) is a polyamide resin having a glass transition temperature (Tg) measured by a differential scanning calorimeter (DSC) of 80°C or higher and 180°C or lower.

[0027] The polyamide resin (A) is not particularly limited as long as the glass transition temperature (Tg) is in the above range, but includes a component unit (a1) derived from a dicarboxylic acid and a component unit (a2) derived from a diamine, and the component unit (a1) derived from a dicarboxylic acid preferably includes a component unit derived from terephthalic acid in an amount of 20 mol% or more and 100 mol% or less based on the total number of moles. Further, the component unit (a2) derived from a diamine preferably includes a component unit derived from an aliphatic diamine having 4 to 20 carbon atoms.

[0028] [Component unit (a1) derived from dicarboxylic acid] The component unit (a1) derived from a dicarboxylic acid (i.e., the component unit derived from a dicarboxylic acid) contains at least a component unit derived from terephthalic acid. The semi-aromatic polyamide resin (A) containing a component unit derived from terephthalic acid has high crystallinity and can enhance the strength of the resin member and the bonding strength of the resin member to the metal member.

[0029] Specifically, the component unit (a1) derived from a dicarboxylic acid contains 20 to 100 mol% of a component unit derived from terephthalic acid, 0 to 80 mol% of a component unit derived from an aromatic dicarboxylic acid other than terephthalic acid, and 0 to 60 mol% of a component unit derived from an aliphatic dicarboxylic acid having 4 to 20 carbon atoms. The component unit (a1) derived from a dicarboxylic acid more preferably contains 30 to 100 mol% of a component unit derived from terephthalic acid, 0 to 70 mol% of a component unit derived from an aromatic dicarboxylic acid other than terephthalic acid, and 0 to 30 mol% of a component unit derived from an aliphatic dicarboxylic acid having 4 to 20 carbon atoms, and even more preferably contains 55 to 100 mol% of a component unit derived from terephthalic acid and 0 to 45 mol% of a component unit derived from an aromatic dicarboxylic acid other than terephthalic acid. However, the total number of moles of the component unit (a1) derived from a dicarboxylic acid is 100 mol%.

[0030] Examples of terephthalic acid include terephthalic acid and terephthalic acid esters (alkyl esters of terephthalic acid having 1 to 4 carbon atoms).

[0031] Examples of aromatic dicarboxylic acids other than terephthalic acid include isophthalic acid, 2-methylterephthalic acid, naphthalenedicarboxylic acid, and their esters. Among these, isophthalic acid is preferred.

[0032] The aliphatic dicarboxylic acid having 4 to 20 carbon atoms is preferably an aliphatic dicarboxylic acid having 6 to 12 carbon atoms. Examples of these aliphatic dicarboxylic acids include dimethylmalonic acid, succinic acid, glutaric acid, adipic acid, 2-methyladipic acid, trimethyladipic acid, pimelic acid, 2,2-dimethylglutaric acid, 3,3-diethylsuccinic acid, azelaic acid, sebacic acid, and suberic acid. Among these, adipic acid is preferred.

[0033] In the component unit (a1) derived from the dicarboxylic acid, the molar ratio of the component unit derived from terephthalic acid to the component unit derived from an aromatic dicarboxylic acid other than terephthalic acid (preferably isophthalic acid) is preferably such that the component unit derived from terephthalic acid / the component unit derived from an aromatic dicarboxylic acid other than terephthalic acid is 55 / 45 to 80 / 20, and more preferably 60 / 40 to 80 / 20. When the amount of the component unit derived from terephthalic acid is within the above range, it is easy to increase the strength of the resin member and the bonding strength of the resin member to the metal member.

[0034] The component unit (a1) derived from the dicarboxylic acid may further contain a component unit derived from an alicyclic dicarboxylic acid as long as the effects of the present invention are not impaired. Examples of the alicyclic dicarboxylic acid include 1,4-cyclohexanedicarboxylic acid and 1,3-cyclohexanedicarboxylic acid.

[0035] [Component unit (a2) derived from diamine] The component unit (a2) derived from the diamine contains a component unit derived from an aliphatic diamine having 4 to 20 carbon atoms, preferably contains a component unit derived from a linear aliphatic diamine having 4 to 8 carbon atoms, and more preferably contains a component unit derived from a linear aliphatic diamine having 6 to 8 carbon atoms.

[0036] Examples of linear aliphatic diamines having 4 to 8 carbon atoms include linear alkylene diamines having 4 to 8 carbon atoms such as 1,4-diaminobutane, 1,6-diaminohexane, 1,7-diaminoheptane, and 1,8-octanediamine. Among these, 1,6-diaminohexane is preferred.

[0037] The component unit derived from an aliphatic diamine having 4 to 20 carbon atoms may further contain a component unit derived from a branched aliphatic diamine having 4 to 15 carbon atoms. Examples of the branched aliphatic diamine having 4 to 15 carbon atoms include 2-methyl-1,8-octanediamine and 2-methyl-1,5-pentanediamine.

[0038] The content of the component unit derived from an aliphatic diamine having 4 to 20 carbon atoms is preferably 30 mol% or more and 100 mol% or less based on the total amount of the component units (a2) derived from the diamine. However, the total number of moles of the component units (a2) derived from the diamine is taken as 100 mol%.

[0039] The component unit (a2) derived from the diamine may further contain a component unit derived from another diamine as long as the effects of the present invention are not impaired. Examples of the other diamine include alicyclic diamines and aromatic diamines.

[0040] Examples of the alicyclic diamine include 1,3-diaminocyclohexane, 1,4-diaminocyclohexane, 1,3-bis(aminomethyl)cyclohexane, 1,4-bis(aminomethyl)cyclohexane, isophoronediamine, piperazine, 2,5-dimethylpiperazine, bis(4-aminocyclohexyl)methane, bis(4-aminocyclohexyl)propane, 4,4'-diamino-3,3'-dimethyldicyclohexylpropane, 4,4'-diamino-3,3'-dimethyldicyclohexylmethane, 4,4'-diamino-3,3'-dimethyl-5,5'-dimethyldicyclohexylmethane, 4,4'-diamino-3,3'-dimethyl-5,5'-dimethyldicyclohexylpropane, α,α'-bis(4-aminocyclohexyl)-p-diisopropylbenzene, α,α'-bis(4-aminocyclohexyl)-m-diisopropylbenzene, α,α'-bis(4-aminocyclohexyl)-1,4-cyclohexane, and α,α'-bis(4-aminocyclohexyl)-1,3-cyclohexane. Examples of the aromatic diamine include metaxylylenediamine. The content of the component unit derived from the other diamine is preferably 50 mol% or less, more preferably 40 mol% or less, based on the total amount of the component unit (a2) derived from the diamine.

[0041] Specific examples of the polyamide resin (A) include a polyamide resin (PA6T6I) in which the component unit (a1) derived from a dicarboxylic acid is a component unit derived from terephthalic acid and a component unit derived from isophthalic acid, and the component unit (a2) derived from a diamine is a component unit derived from 1,6-diaminohexane; a polyamide resin (PA6T66) in which the component unit (a1) derived from a dicarboxylic acid is a component unit derived from terephthalic acid and a component unit derived from adipic acid, and the component unit derived from a diamine is a component unit derived from 1,6-diaminohexane; a polyamide resin (PA6TDT) in which the component unit (a1) derived from a dicarboxylic acid is a component unit derived from terephthalic acid, and the component unit derived from a diamine is a component unit derived from 1,6-diaminohexane and a component unit derived from 2-methyl-1,5-pentanediamine, etc. The polyamide resin (A) may contain only one kind or two or more kinds.

[0042] From the viewpoints of enhancing the heat stability during compounding and molding or further enhancing the mechanical strength, at least a part of the end groups of the molecules of the polyamide resin (A) may be blocked with an end-capping agent. When the molecular end is a carboxyl group, for example, the end-capping agent is preferably a monoamine, and when the molecular end is an amino group, the end-capping agent is preferably a monocarboxylic acid.

[0043] Examples of monoamines include aliphatic monoamines such as methylamine, ethylamine, propylamine, and butylamine, alicyclic monoamines such as cyclohexylamine and dicyclohexylamine, and aromatic monoamines such as aniline and toluidine. Examples of monocarboxylic acids include aliphatic monocarboxylic acids having 2 to 30 carbon atoms such as acetic acid, propionic acid, butyric acid, valeric acid, caproic acid, caprylic acid, lauric acid, tridecylic acid, myristic acid, palmitic acid, stearic acid, oleic acid, and linoleic acid, aromatic monocarboxylic acids such as benzoic acid, toluic acid, naphthalenecarboxylic acid, methylnaphthalenecarboxylic acid, and phenylacetic acid, and alicyclic monocarboxylic acids such as cyclohexanecarboxylic acid. The aromatic monocarboxylic acid and the alicyclic monocarboxylic acid may have a substituent in the cyclic structure portion.

[0044] [Physical properties] The polyamide resin (A) can have a melting point (Tm) of 280°C or higher and 340°C or lower. When the melting point (Tm) of the polyamide resin (A) is 280°C or higher, the mechanical strength and heat resistance in the high-temperature range of the resin composition and the molded article are less likely to be impaired. When it is 340°C or lower, it is not necessary to excessively increase the molding temperature, so the molding processability of the resin composition tends to be good. From the above viewpoints, the melting point (Tm) of the polyamide resin is more preferably 290°C or higher and 340°C or lower, and even more preferably 300°C or higher and 340°C or lower.

[0045] The polyamide resin (A) preferably has a glass transition temperature (Tg) of 90°C or higher and 170°C or lower, more preferably 100°C or higher and 160°C or lower, and even more preferably 120°C or higher and 150°C or lower.

[0046] The polyamide resin (A) preferably has a crystallization temperature (Tc) of 240°C or higher, more preferably 260°C or higher. When the crystallization temperature (Tc) of the polyamide resin (A) is 240°C or higher, it becomes easier to crystallize the polyamide resin composition, and the mechanical strength and bonding strength of the resin member can be further increased. Although the upper limit of the crystallization temperature (Tc) of the polyamide resin (A) is not particularly limited, it can be less than 330°C, preferably less than 300°C, and more preferably less than 280°C.

[0047] The heat of fusion (ΔH) of the polyamide resin (A) is preferably 20 J / g or more. When the heat of fusion (ΔH) of the polyamide resin (A) is 20 J / g or more, since it has crystallinity, it is easy to enhance the heat resistance of the resin member. The upper limit value of the heat of fusion (ΔH) of the polyamide resin (A) is not particularly limited, but from the viewpoint of not impairing the moldability, it can be 130 J / g. The heat of fusion (ΔH) of the polyamide resin (A) is preferably 30 J / g or more and 130 J / g or less, and more preferably 30 J / g or more and 100 J / g or less.

[0048] The heat of fusion (ΔH), melting point (Tm), and glass transition temperature (Tg) of the polyamide resin can be measured using a differential scanning calorimeter (DSC220C type, manufactured by Seiko Instruments Inc.).

[0049] Specifically, about 5 mg of the polyamide resin is sealed in a measurement aluminum pan and heated from room temperature to 350°C at 10°C / min. To completely melt the resin, it is held at 360°C for 3 minutes, 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 360°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 crystalline polyamide resin, the exothermic peak is defined as the crystallization temperature (Tc), 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 of crystallization in the first heating process according to JIS K7122.

[0050] The melting point (Tm), glass transition temperature (Tg), and heat of fusion (ΔH) of the crystalline polyamide resin can be adjusted by the structure of the component unit (a) derived from the dicarboxylic acid, the structure of the component unit (a) derived from the diamine, and the like.

[0051] The intrinsic viscosity [η] of the polyamide resin (A) measured in 96.5% sulfuric acid at 25°C is preferably 0.6 dl / g or more and 1.5 dl / g or less. When the intrinsic viscosity [η] of the polyamide resin (A) is 0.6 dl / g or more, it is easy to sufficiently increase the mechanical strength (such as toughness) of the molded body. When it is 1.5 dl / g or less, the fluidity during molding of the resin composition is less likely to be impaired. From the same viewpoint, the intrinsic viscosity [η] of the polyamide resin (A) is more preferably 0.8 dl / g or more and 1.2 dl / g or less. The intrinsic viscosity [η] can be adjusted by the amount of end capping of the polyamide resin (A) and the like.

[0052] The intrinsic viscosity of the crystalline polyamide resin can be measured in accordance with JIS K6810-1977. Specifically, 0.5 g of the crystalline polyamide resin is dissolved in 50 ml of a 96.5% sulfuric acid solution to obtain a sample solution. The flow-down time in seconds of this sample solution is measured under the condition of 25 ± 0.05°C using an Ubbelohde viscometer, and the obtained value can be calculated by applying it to the following formula. [η]=ηSP / [C(1 + 0.205ηSP)]

[0053] In the above formula, each algebraic expression or variable represents the following. [η]: Intrinsic viscosity (dl / g) ηSP: Specific viscosity C: Sample concentration (g / dl)

[0054] ηSP is obtained by the following formula. ηSP=(t - t0) / t0 t: Flow-down time in seconds of the sample solution (seconds) t0: Flow-down time in seconds of the blank sulfuric acid (seconds)

[0055] [Production method] The polyamide resin can be produced, for example, by polycondensing the aforementioned dicarboxylic acid and the aforementioned diamine in a homogeneous solution. Specifically, the dicarboxylic acid and the diamine are heated in the presence of a catalyst as described in International Publication No. 03 / 085029 to obtain a low-order condensate, and then the melt of this low-order condensate is subjected to shear stress and polycondensed to produce it.

[0056] From the viewpoint of adjusting the intrinsic viscosity of the polyamide resin, etc., the aforementioned end-capping agent may be added to the reaction system. The intrinsic viscosity [η] (or molecular weight) of the polyamide resin can be adjusted by the addition amount of the end-capping agent.

[0057] The end-capping agent is added to the reaction system of the dicarboxylic acid and the diamine. The addition amount is preferably 0.07 mol or less, more preferably 0.05 mol or less, based on 1 mol of the total amount of the dicarboxylic acid.

[0058] The content of the polyamide resin (A) is preferably 35% by mass or more and 95% by mass or less, more preferably 40% by mass or more and 95% by mass or less, still more preferably 55% by mass or more and 95% by mass or less, particularly preferably 70% by mass or more and 95% by mass or less, based on the total mass of the polyamide resin (A) and the polyamide resin (B). The higher the content of the polyamide resin (A), the higher the bonding strength of the resin member to the metal member can be. On the other hand, in order to leave room for obtaining the effect of suppressing the decrease in the bonding strength when the mold temperature is lowered by adding the polyamide resin (B), the upper limit of the polyamide resin (A) can be within the above range.

[0059] 1-2-2. Polyamide resin (B) The polyamide resin (B) is a polyamide resin having a glass transition temperature (Tg) of 70°C or lower measured by a differential scanning calorimeter (DSC).

[0060] The polyamide resin (B) may be a polyamide resin with an observed melting point (Tm), or may be a polyamide resin without an observed melting point (Tm). Also, a polyamide resin with an observed melting point (Tm) and a polyamide resin without an observed melting point (Tm) may be used in combination. Among these, a polyamide resin with an observed melting point (Tm) is preferred. When it is a polyamide resin with an observed melting point (Tm), the polyamide resin (B) preferably has a melting point (Tm) of less than 280°C, more preferably less than 220°C, and even more preferably less than 150°C. Although the lower limit value of the melting point (Tm) of the polyamide resin (B) is not particularly limited, it can be 80°C or higher.

[0061] Since the polyamide resin (B) has a lower glass transition temperature (Tg) than the polyamide resin (A), it facilitates solidification of the polyamide resin composition even when injection molding is performed at a low temperature. Therefore, it is considered that a decrease in bonding strength when injection molding is performed at a low temperature can be suppressed. From the above viewpoints, the glass transition temperature (Tg) of the polyamide resin (B) is preferably 65°C or lower, more preferably 55°C or lower, and even more preferably 0°C or lower.

[0062] Also, from the viewpoint of enhancing the fluidity of the polyamide resin composition and shortening the manufacturing time when injection molding is performed with a low mold temperature, the polyamide resin (B) preferably has a crystallization temperature (Tc) of less than 240°C, more preferably less than 200°C, even more preferably less than 150°C, and particularly preferably less than 100°C. Although the lower limit value of the crystallization temperature (Tc) of the polyamide resin (B) is not particularly limited, it can be 50°C or higher.

[0063] The melting point (Tm), crystallization temperature (Tc), and glass transition temperature (Tg) of the polyamide resin (B) can be adjusted by the type and composition of the raw material monomers, etc.

[0064] The melting point (Tm), crystallization temperature (Tc), and glass transition temperature (Tg) of the polyamide resin (B) can be measured in the same manner as the polyamide resin (A).

[0065] The polyamide resin (B) only needs to have a glass transition temperature (Tg) of 70°C or lower, and its type is not particularly limited. However, it is preferably an aliphatic polyamide having a carbon chain with 6 to 50 carbon atoms, preferably 10 to 50 carbon atoms. The above carbon chain may be saturated or may have an unsaturated portion. Further, the above carbon chain may contain a branch. Examples of the polyamide resin (B) include nylon 6, nylon 9, nylon 11, nylon 12, nylon 66, nylon 610, nylon 612, and polyamides containing component units derived from dimer acid. Among these, polyamides containing component units derived from nylon 12, nylon 612, and dimer acid are preferred.

[0066] The polyamide containing component units derived from dimer acid may be a polyamide obtained by reacting dimer acid (having 36 carbon atoms) as a dicarboxylic acid with a diamine, or may be a polyamide obtained by reacting dimer acid with ammonia, followed by dehydration, nitrilation, and reduction, and then reacting the resulting dimer diamine with a dicarboxylic acid, or may be a polyamide obtained by reacting dimer acid with dimer diamine.

[0067] The content of the polyamide resin (B) is preferably 5% by mass or more and 65% by mass or less, more preferably 5% by mass or more and 60% by mass or less, still more preferably 5% by mass or more and 45% by mass or less, and still more preferably 5% by mass or more and 30% by mass or less, based on the total mass of the polyamide resin (A) and the polyamide resin (B). The more the content of the polyamide resin (B) is increased, the more effectively the decrease in the bonding strength when injection molding is performed at a low mold temperature can be suppressed. On the other hand, in order to leave room for further improving the bonding strength by sufficiently increasing the amount of the polyamide resin (A), the upper limit of the polyamide resin (B) can be within the above range.

[0068] 1-2-3. Polyamide resin (C) In addition to polyamide resin (A) and polyamide resin (B), the resin member preferably contains polyamide resin (C) 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. Polyamide resin (C) preferably exhibits amorphous properties. Further, in differential scanning calorimetry (DSC), it is preferable that the melting point (Tm) of polyamide resin (C) is not substantially measured. Since polyamide resin (C) has a lower crystallinity than polyamide resin (A), the crystallization rate of the resin composition during molding of the resin member can be delayed. As a result, the resin composition constituting the resin member can be sufficiently flowed along the unevenness on the surface of the roughened metal member, and the resin composition can be sufficiently adhered to the unevenness. Therefore, it is considered that polyamide resin (C) can further increase the bonding strength between the metal member and the resin member.

[0069] "The melting point (Tm) is not substantially measured" means that in the above-described measurement method, a discontinuous point corresponding to the melting point is not substantially observed.

[0070] Polyamide resin (C) can be a polyamide resin containing a component unit (c1) derived from a dicarboxylic acid and a component unit (c2) derived from a diamine.

[0071] [Component unit (c1) derived from dicarboxylic acid] The component unit (c1) derived from a dicarboxylic acid preferably contains at least a component unit derived from isophthalic acid. The component unit derived from isophthalic acid can lower the crystallinity of polyamide resin (C).

[0072] The content of the component unit derived from isophthalic acid is preferably 40 mol% or more, more preferably 50 mol% or more, based on the total amount of the component units (c1) derived from dicarboxylic acids. When the content of the component unit derived from isophthalic acid is 40 mol% or more, it is easy to make polyamide resin (C) amorphous. Although the upper limit of the content of the component unit derived from isophthalic acid is not particularly limited, it can be 100 mol% or less, preferably 90 mol% or less.

[0073] The component unit (c1) derived from the dicarboxylic acid may further contain a component unit derived from a dicarboxylic acid other than isophthalic acid, 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 acid and the alicyclic dicarboxylic acid may be the same as the above-mentioned aliphatic dicarboxylic acid and alicyclic dicarboxylic acid, respectively. Among them, aromatic dicarboxylic acids other than isophthalic acid are preferable, and terephthalic acid is more preferable.

[0074] In the component unit (c1) derived from the dicarboxylic acid, the molar ratio of the component unit derived from isophthalic acid to the component unit derived from an aromatic dicarboxylic acid other than isophthalic acid (preferably terephthalic acid) is preferably such that the component unit derived from isophthalic acid / the component unit derived from an aromatic dicarboxylic acid other than isophthalic acid is 55 / 45 to 100 / 0, and more preferably 60 / 40 to 90 / 10. When the amount of the component unit derived from isophthalic acid is a certain amount or more, the polyamide resin (C) is likely to be amorphous, and the crystallization rate of the resin composition during the molding of the resin member is delayed, making it easier to increase the bonding strength between the metal member and the resin member.

[0075] [Component unit (c2) derived from diamine] The component unit (c2) derived from the diamine preferably contains a component unit derived from an aliphatic diamine having 4 to 15 carbon atoms.

[0076] The aliphatic diamine having 4 to 15 carbon atoms is the same as the above-mentioned aliphatic diamine having 4 to 15 carbon atoms, and is preferably 1,6-hexanediamine.

[0077] The content of the component unit derived from the aliphatic diamine having 4 to 15 carbon atoms is preferably 50 mol% or more, and more preferably 60 mol% or more, based on the total amount of the component units (Bb) derived from the diamine.

[0078] The component unit (c2) derived from diamine may further contain a component unit derived from a diamine other than an aliphatic diamine having 4 to 15 carbon atoms, as long as the effects of the present invention are not impaired. Examples of other diamines include alicyclic diamines and aromatic diamines. The alicyclic diamines and aromatic diamines may be the same as the aforementioned alicyclic diamines and aromatic diamines, respectively. The content of the component unit derived from other diamines is 50 mol% or less, preferably 40 mol% or less.

[0079] Specific examples of the polyamide resin (C) include polycondensates of isophthalic acid / terephthalic acid / 1,6-hexanediamine / bis(3-methyl-4-aminocyclohexyl)methane, polycondensates of isophthalic acid / bis(3-methyl-4-aminocyclohexyl)methane / ω-laurolactam, polycondensates of isophthalic acid / terephthalic acid / 1,6-hexanediamine, polycondensates of isophthalic acid / 2,2,4-trimethyl-1,6-hexanediamine / 2,4,4-trimethyl-1,6-hexanediamine, polycondensates of isophthalic acid / terephthalic acid / 2,2,4-trimethyl-1,6-hexanediamine / 2,4,4-trimethyl-1,6-hexanediamine, polycondensates of isophthalic acid / bis(3-methyl-4-aminocyclohexyl)methane / ω-laurolactam, and polycondensates of isophthalic acid / terephthalic acid / other diamine components. Among them, a polycondensate of isophthalic acid / terephthalic acid / 1,6-hexanediamine is preferred. The polyamide resin (B) may be contained alone or in two or more kinds.

[0080] The intrinsic viscosity [η] of the polyamide resin (C) measured in 96.5% sulfuric acid at 25°C is preferably 0.6 to 1.6 dl / g, more preferably 0.65 to 1.2 dl / g. The intrinsic viscosity [η] of the polyamide resin (C) can be measured in the same manner as the intrinsic viscosity [η] of the aforementioned polyamide resin (A).

[0081] The intrinsic viscosity [η] of the polyamide resin (C) can be measured in the same manner as the polyamide resin (A).

[0082] The polyamide resin (C) can be produced in the same manner as the aforementioned polyamide resin (A).

[0083] The content of the polyamide resin (C) is preferably 5% by mass or more, more preferably 8% by mass or more, and even more preferably 10% by mass or more based on the total mass of the polyamide resin. By setting the proportion of the polyamide resin (C) within the above range, the effect of improving the bonding strength due to the delay in crystallization can be more sufficiently exhibited. The upper limit of the proportion of the polyamide resin (C) among the resin components is not particularly limited, but from the viewpoint of blending a sufficient amount of the polyamide resin (A) and the polyamide resin (B) into the resin composition, it can be 30% by mass or less, and may be 25% by mass or less.

[0084] 1-2-5. Other Components The resin member may contain other known components.

[0085] Examples of other components include crystal nucleating agents, reinforcing materials, lubricants (fluidity improvers), colorants, corrosion resistance improvers, drip preventers, ion scavengers, elastomers (rubbers), antistatic agents, mold release agents, antioxidants (such as phenols, amines, sulfurs, and phosphorus compounds), heat stabilizers other than the above (such as lactone compounds, vitamin E compounds, and hydroquinones), light stabilizers (such as benzotriazoles, triazines, benzophenones, benzoates, hindered amines, and oxanilides), and other polymers (such as olefin copolymers such as polyolefins, ethylene-propylene copolymers, and ethylene-1-butene copolymers, olefin copolymers such as propylene-1-butene copolymers, polystyrene, polyamide, polycarbonate, polyacetal, polysulfone, polyphenylene oxide, fluororesin, silicone resin, and LCP). Among them, from the viewpoint of enhancing the mechanical strength of the molded article, the resin composition constituting the resin member preferably further contains a reinforcing material.

[0086] The crystal nucleating agent can increase the crystallinity of the molded article. Examples of the crystal nucleating agent include metal salt-based compounds such as 2,2-methylenebis(4,6-di-t-butylphenyl) sodium phosphate, aluminum tris(p-t-butylbenzoate), and stearates, sorbitol-based compounds such as bis(p-methylbenzylidene)sorbitol and bis(4-ethylbenzylidene)sorbitol, and inorganic substances such as talc, calcium carbonate, and hydrotalcite. Among these, from the viewpoint of further increasing the crystallinity of the molded article, talc is preferred. These crystal nucleating agents may be used alone or in combination of two or more.

[0087] The content of the crystal nucleating agent is preferably 0.1 part by mass or more and 5 parts by mass or less, more preferably 0.1 part by mass or more and 3 parts by mass or less, based on the total mass of the resin composition. When the content of the crystal nucleating agent is within the above range, it is easy to sufficiently increase the crystallinity of the molded article, and sufficient mechanical strength can be easily obtained.

[0088] The reinforcing material can impart high mechanical strength to the resin composition. 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, plate-like or scaly reinforcing materials such as mica, and granular 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 preferred, and wollastonite or glass fiber is more preferred, because it is easy to increase the mechanical strength of the molded article.

[0089] The average fiber length of the fibrous reinforcing material can be, for example, 1 μm or more and 20 mm or less, preferably 5 μm or more and 10 mm or less, from the viewpoints of the moldability of the resin composition and the mechanical strength and heat resistance of the obtained molded article. Also, the aspect ratio of the fibrous reinforcing material can be, for example, 5 or more and 2000 or less, preferably 30 or more and 600 or less.

[0090] The average fiber length and average fiber diameter of the fibrous reinforcing material can be measured by the following method. 1) After dissolving the resin composition in a hexafluoroisopropanol / chloroform solution (0.1 / 0.9% by volume), collect the filtrate obtained by filtration. 2) Disperse the filtrate obtained in 1) 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, 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)

[0091] The content of the reinforcing material is not particularly limited, but it can be, for example, 15% by mass or more and 70% by mass or less, preferably 40% by mass or more and 70% by mass or less, based on the total mass of the resin composition. The higher the content of the reinforcing material, the higher the bonding strength of the resin member can be increased.

[0092] The crystal nucleating agent can increase the crystallinity of the molded body. Examples of the crystal nucleating agent include metal salt compounds containing phosphoric acid-2,2-methylenebis(4,6-di-t-butylphenyl) sodium, tris(p-t-butylbenzoic acid) aluminum, and stearates, sorbitol compounds containing bis(p-methylbenzylidene) sorbitol, and bis(4-ethylbenzylidene) sorbitol, and inorganic substances containing talc, calcium carbonate, and hydrotalcite. Among these, from the viewpoint of further increasing the crystallinity of the molded body, talc is preferred. These crystal nucleating agents may be used alone or in combination of two or more.

[0093] The content of the crystallization nucleating agent is preferably 0.1 part by mass or more and 5 parts by mass or less, more preferably 0.1 part by mass or more and 3 parts by mass or less, based on the total mass of the resin composition. When the content of the crystallization nucleating agent is within the above range, it is easy to sufficiently increase the crystallinity of the molded body, and it is easy to obtain sufficient mechanical strength.

[0094] The lubricant enhances the injection fluidity of the resin composition and improves the appearance of the resulting molded body. The lubricant can be a fatty acid metal salt such as a metal salt of oxycarboxylic acid and a metal salt of higher fatty acid.

[0095] The oxycarboxylic acid constituting the above metal salt of oxycarboxylic acid may be an aliphatic oxycarboxylic acid or an aromatic oxycarboxylic acid. Examples of the above 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 above aromatic oxycarboxylic acid include salicylic acid, m-oxybenzoic acid, p-oxybenzoic acid, gallic acid, mandelic acid, and tropic acid.

[0096] Examples of the metal constituting the above metal salt of oxycarboxylic acid include alkali metals such as lithium, and alkaline earth metals such as magnesium, calcium, and barium.

[0097] Among these, the metal salt of oxycarboxylic acid is preferably a metal salt of 12-hydroxystearic acid, more preferably magnesium 12-hydroxystearate and calcium 12-hydroxystearate.

[0098] 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, behenic acid, and montanic acid.

[0099] Examples of the metal constituting the above higher fatty acid metal salt include calcium, magnesium, barium, lithium, aluminum, zinc, sodium, and potassium.

[0100] Among these, the above higher fatty acid metal salt is preferably calcium stearate, magnesium stearate, barium stearate, calcium behenate, sodium montanate, calcium montanate, etc.

[0101] The content of the lubricant is preferably 0.01% by mass or more and 1.3% by mass or less based on the total mass of the 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 obtained molded product is likely to improve. When the content of the lubricant is 1.3% by mass or less, gas generated by the decomposition of the lubricant is less likely to be generated during molding, and the appearance of the product is likely to be good.

[0102] The colorant imparts a desired color tone to the molded body. 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, barium sulfate; and organic pigments such as azo pigments, phthalocyanine pigments, quinacridone pigments, perylene pigments, anthraquinone pigments, thioindigo pigments, indanthrene pigments.

[0103] The content of the colorant is preferably 0.01% by mass or more and 5% by mass or less, more preferably 0.1% by mass or more and 2% by mass or less based on the total mass of the resin composition.

[0104] 1-2-6. Manufacturing method The above resin composition can be produced by mixing the aforementioned polyamide resin and, if necessary, other components by a known resin kneading method, such as a method of mixing with a Henschel mixer, a V blender, a ribbon blender, or a tumbler blender, or, after mixing, further melt-kneading with a single-screw extruder, a multi-screw extruder, a kneader, or a Banbury mixer, and then granulating or pulverizing.

[0105] 1-3. Method for manufacturing a metal-resin bonded body The method for manufacturing a metal-resin composite structure is not particularly limited. For example, it has (1) a step of preparing a metal member whose surface has been roughened, and (2) a step of injecting a molten resin composition onto the roughened surface of the metal member and solidifying it to bond a resin member.

[0106] 1-3-1. Preparation of a roughened metal member First, a metal member having an uneven structure on at least a part of its surface is prepared.

[0107] The method for obtaining a metal member having a fine uneven structure is not particularly limited. For example, a method using laser processing, a method of immersing a 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 a metal member by an anodizing method, a substitution precipitation method of etching 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 such as hydrazine hydrate, ammonia, and a water-soluble amine compound, and a hot water treatment method can be used.

[0108] 1-3-2. Bonding of the resin member The prepared metal member having a roughened surface is placed in a cavity portion (space portion) in an injection molding die.

[0109] Then, the resin composition is injected into the cavity portion of the mold so that at least a part of the resin composition contacts the roughened surface of the metal member. Thereafter, it is cooled and solidified to join the metal member and the resin member.

[0110] The temperature of the injection molding die may be any temperature that can melt the resin composition into a state suitable for injection molding, and is not particularly limited. For example, it can be 100 to 350 °C, but it is preferably 100 to 160 °C. Even when the mold temperature is set to such a low temperature, the resin composition is less likely to cause a decrease in bonding strength.

[0111] After injection and holding pressure, the mold is cooled, then the mold is opened, and if necessary, the metal resin composite can be obtained by protruding it using an ejector pin.

[0112] As the mold, a known injection molding die can be used, for example, a die for rapid heat cycle molding (RHCM, heat & cool molding) or a core-back die for foam molding.

[0113] Examples of the uses of the metal resin composite include vehicle structural parts, vehicle-mounted products, casings of electronic devices, casings of household electrical appliances, structural parts, mechanical parts, various automotive parts, parts for electronic devices, furniture, household goods for household use such as kitchen utensils, medical devices, parts of building materials, and other structural parts and exterior parts.

[0114] More specific examples of the uses of the above metal resin composite include parts designed such that the metal supports portions where the strength of the resin alone is insufficient. Examples of such parts 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, radiators, oil pans, steering wheels, ECU boxes, and electrical components, etc. Also, in building materials or furniture, glass window frames, handrails, curtain rails, chests of drawers, drawers, closets, bookshelves, desks, and chairs, etc. are included. Further, as precision electronic components, connectors, relays, and gears, etc. are included. Also, as transport containers, transport containers, suitcases, and trunks, etc. are included.

[0115] Moreover, other more specific examples of the uses of the above metal resin composite include part applications used in equipment that optimally designs heat management by combining the high thermal conductivity of the metal member and the heat insulating properties of the molded body of the resin composition. Examples of such parts include home appliances such as refrigerators, washing machines, vacuum cleaners, microwave ovens, air conditioners, lighting equipment, electric kettles, televisions, clocks, ventilation fans, projectors, and speakers, 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, etc.

[0116] Other uses include toys, sports equipment, shoes, sandals, bags, tableware such as forks, knives, spoons, and plates, stationery such as ballpoint pens, sharp pens, files, and binders, cooking utensils such as frying pans, pots, kettles, frying pans, balls, ladles, whisks, and tongs, parts for lithium-ion secondary batteries, robots, etc.

Examples

[0117] Hereinafter, the present invention will be described more specifically with reference to examples, but the scope of the present invention is not limited to the description of the examples.

[0118] In the following experiments, the melting point (Tm), crystallization temperature (Tc), glass transition temperature (Tg), intrinsic viscosity [η], and heat of fusion (ΔH) of the polyamide resin were measured by the following methods.

[0119] (Melting point (Tm), crystallization temperature (Tc), glass transition temperature (Tg), heat of fusion (ΔH)) The heat of fusion (ΔH), melting point (Tm), and glass transition temperature (Tg) of the polyamide resin were measured using a differential scanning calorimeter (DSC220C type, manufactured by Seiko Instruments Inc.).

[0120] Specifically, about 5 mg of the polyamide resin was sealed in a measurement aluminum pan and heated from room temperature to 350 °C at 10 °C / min. To completely melt the resin, it was held at 360 °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 360 °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 crystalline polyamide resin, the temperature (°C) of the exothermic peak was defined as the crystallization temperature (Tc), and the inflection point corresponding to the glass transition was defined as the glass transition temperature (Tg). The heat of fusion (ΔH) was determined from the area of the endothermic peak of crystallization in the first heating process according to JIS K7122.

[0121] (Intrinsic viscosity [η]) The intrinsic viscosity [η] of the polyamide resin 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]: 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 the blank sulfuric acid (seconds) ηSP = (t - t0) / t0

[0122] 1. Synthesis / Preparation of Polyamide Resin 1-1. Synthesis of Polyamide Resin (A) 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 an autoclave with an internal volume of 13.6 L 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 increased to 3.03 MPa. After continuing the reaction for 1 hour, atmospheric release was carried out from the spray nozzle installed at the bottom of the autoclave to extract the low-order condensate. Then, after cooling this low condensate to room temperature, the low condensate was pulverized with a pulverizer to a particle size of 1.5 mm or less and dried at 110 °C for 24 hours. The moisture content of the obtained low-order condensate was 4100 ppm, and the intrinsic viscosity [η] was 0.15 dl / g.

[0123] Next, this low-order condensate was placed in a shelf-type solid-phase polymerization apparatus. After purging with nitrogen, the temperature was raised to 180 °C over about 1 hour and 30 minutes. Then, it was reacted for 1 hour and 30 minutes and cooled to room temperature. The intrinsic viscosity [η] of the obtained prepolymer was 0.20 dl / g. Thereafter, the obtained prepolymer was melt-polymerized in a twin-screw extruder with a screw diameter of 30 mm and L / D = 36 at a barrel set temperature of 330 °C, a screw rotation speed of 200 rpm, and a resin supply rate of 6 kg / h to obtain polyamide resin (A-1).

[0124] The intrinsic viscosity of the obtained polyamide resin (A-1) was 1.0 dl / g, the melting point (Tm) was 330 °C, the crystallization temperature (Tc) was 285 °C, the glass transition temperature (Tg) was 125 °C, and the heat of fusion (ΔH) was 50 J / g.

[0125] 1-1-2. Polyamide Resin (A-2) 1,6 - hexanediamine 2800 g (24.1 mol), terephthalic acid 1390 g (8.4 mol), isophthalic acid 2581 g (15.5 mol), benzoic acid 109.5 g (0.9 mol), sodium hypophosphite monohydrate 5.7 g and distilled water 545 g were placed in an autoclave with an internal volume of 13.6 L 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 increased to 3.02 MPa. After continuing the reaction for 1 hour, the autoclave was depressurized to the atmosphere from the spray nozzle installed at the bottom of the autoclave to extract the low - order condensate. Then, after cooling the low - order condensate to room temperature, it was pulverized to a particle size of 1.5 mm or less with a pulverizer and dried at 110 °C for 24 hours. The water content of the obtained low - order condensate was 3000 ppm, and the intrinsic viscosity [η] was 0.14 dl / g.

[0126] Next, this low - order condensate was melt - polymerized in a twin - screw extruder with a screw diameter of 30 mm and L / D = 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 (B - 1).

[0127] The intrinsic viscosity [η] of the obtained polyamide resin (B - 1) was 0.68 dl / g, the melting point (Tm) and crystallization temperature (Tc) were not measured, the glass transition temperature (Tg) was 125 °C, and the heat of fusion (ΔH) was 0 J / g.

[0128] 1 - 2. Preparation of polyamide resin (B) As the polyamide resin (B), the following polyamide resins were prepared. · Polyamide resin (B - 1): Nylon 12 (melting point (Tm) is 180 °C, crystallization temperature (Tc) is 140 °C, glass transition temperature is 50 °C) · Polyamide resin (B - 2): Nylon 66 (melting point (Tm) is 260 °C, crystallization temperature (Tc) is 230 °C, glass transition temperature is 50 °C) · Polyamide resin (B - 3): Dimer acid - based polyamide (melting point (Tm) is 110 °C, crystallization temperature (Tc) is 70 °C, glass transition temperature is - 20 °C)

[0129] 1-1-3. Preparation of Polyamide Resin (C) 1390 g (8.4 mol) of terephthalic acid, 2800 g (24.1 mol) of 1,6-diaminohexane, 2581 g (15.5 mol) of isophthalic acid, 109.5 g (0.9 mol) of benzoic acid, 5.7 g of sodium hypophosphite monohydrate and 545 g of distilled water were placed in an autoclave with an internal volume of 13.6 L 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 increased to 3.02 MPa. After continuing the reaction for 1 hour, the mixture was released to the atmosphere from the spray nozzle installed at the bottom of the autoclave to extract the low condensate. Then, after cooling to room temperature, it was pulverized with a pulverizer to a particle size of 1.5 mm or less and dried at 110°C for 24 hours. The water content of the obtained low condensate was 3000 ppm, and the limiting viscosity [η] was 0.14 dl / g.

[0130] Next, this low condensate was melt-polymerized using a twin-screw extruder with a screw diameter of 30 mm and L / D = 36 at a barrel set temperature of 330°C, a screw rotation speed of 200 rpm, and a resin supply rate of 6 kg / hour to prepare polyamide resin (C). The limiting viscosity [η] of the obtained polyamide resin (C) was 0.68 dl / g, the melting point (Tm) and crystallization temperature (Tc) were not observed, and the glass transition temperature (Tg) was 125°C. The heat of fusion (ΔH) of polyamide resin (C) was determined from the area of the exothermic peak of crystallization according to JIS K7122, and it was 0 J / g.

[0131] 1-2. Crystal Nucleating Agent (D) The following materials were prepared as the crystal nucleating agent (D). · Talc (average particle size 6 μm)

[0132] 1-3. Reinforcing Material (E) The following materials were prepared as the reinforcing material (E). · Glass fiber (manufactured by Owens Corning, FT2A)

[0133] 1-4. Lubricant (F) The following materials were prepared as the lubricant (F). · Sodium montanate

[0134] 2. Preparation of Metal-Resin Composite 2-1. 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 the cylinder temperature condition of 300 to 335 °C using a 30 mmφ vented twin-screw extruder. Thereafter, the kneaded product was extruded in a strand shape and cooled in a water tank. Then, the strand was taken up by a pelletizer and cut to obtain a pelletized polyamide resin composition.

[0135] 2-2. Preparation of Metal Member 2-2-1. Preparation of Rough-Surfaced Aluminum Member An aluminum plate of alloy number A6063 (thickness: 2 mm) was cut into a length of 45 mm and a width of 18 mm. The surface of the cut aluminum plate was roughened by the method described in International Publication No. WO2008 / 133096.

[0136] 2-2-1. Preparation of Rough-Surfaced Copper Member A copper alloy plate of alloy number C1100 (thickness 2 mm) was cut into a length of 45 mm and a width of 18 mm. After degreasing the cut copper alloy plate, it was immersed in a chemical etching agent (manufactured by Meck Co., Ltd., Amalfa A-10201H), washed with water, and immersed in the chemical etching agent in this order. Immediately thereafter, the same member was immersed in the chemical etching agent for 4 minutes. Next, washing with water, alkali washing (5 mass% NAOH, immersion for 20 seconds), washing with water, neutralization treatment (5 mass% H2SO4, immersion for 20 seconds), washing with water, rust prevention treatment (A-10290, 1 minute) and washing with water were carried out in this order.

[0137] 2-3. Preparation of Metal-Resin Composite The roughened metal member was placed in a small dumbbell metal insert mold attached to an injection molding machine (manufactured by Nippon Steel Works, Ltd., J55-AD). Next, each of the above polyamide resin compositions was injection molded into the mold under the conditions of a cylinder temperature of 335°C, a primary injection pressure of 90 MPa, a holding pressure of 80 MPa, and an injection speed of 25 mm / sec to produce a test piece in which a resin member made of polyamide resin was joined to the surface of the metal member. The joint area between the metal member and the resin member of this test piece was 50 mm 2 was.

[0138] In addition, two test pieces were produced from the same material with the mold temperature during injection molding set at 150°C and 170°C.

[0139] 3. Evaluation The obtained metal-resin bonded body and each polyamide resin composition were evaluated according to the following criteria.

[0140] 3-1. Bonding strength The shear bonding strength (MPa) of the produced test piece was measured by a method conforming to ISO19095. Specifically, a dedicated jig was attached to a tensile testing machine (manufactured by AIKO Engineering Co., Ltd., model 1323), and at room temperature (23°C), under the conditions of a chuck distance of 60 mm and a tensile speed of 10 mm / min, the breaking load (N) was measured. The measured breaking load (N) was divided by the area (50 mm 2 ) of the joint portion between the metal member and the resin member to obtain the shear bonding strength (MPa).

[0141] Also, the bonding strength of the test piece produced with the mold temperature at 150°C was divided by the bonding strength of the test piece produced with the mold temperature at 170°C to obtain the retention rate of the bonding strength when the mold temperature was lowered.

[0142] 3-2. Fluidity Using an injection molding machine with a clamping force of 50 t and having a 3.8 mmφ semi-circular spiral groove mold, injection molding was carried out at a cylinder temperature of 335°C, an injection pressure of 100 MPa, and a mold temperature of 160°C, and the flow distance was measured.

[0143] Table 1 and Table 2 show the types of each component contained in the polyamide resin composition in each test and the (mass ratio to the total mass of the resin composition), as well as the evaluation results of the bonding strength and fluidity.

[0144]

Table 1

[0145]

Table 2

[0146] As shown in Table 1 and Table 2, when a resin member containing a polyamide resin composition containing a polyamide resin (A) having a glass transition temperature Tg measured by a differential scanning calorimeter (DSC) of 80°C or higher and 160°C or lower and a polyamide resin (B) having a glass transition temperature Tg measured by a differential scanning calorimeter (DSC) of 70°C or lower is joined to a metal member, a decrease in the bonding force when the resin member is injection-molded at a low temperature hardly occurs.

Industrial Applicability

[0147] According to the present invention, a metal-resin composite having a desired bonding strength can be manufactured at a lower temperature. Therefore, the present invention is expected to contribute to the further spread of metal-resin composites by shortening the manufacturing time and reducing the manufacturing cost of metal-resin composites.

Claims

1. A metal member, A resin member joined to the surface of the metal member, A metal-resin composite having, The resin member is, A polyamide resin (A) having a glass transition temperature Tg measured by a differential scanning calorimeter (DSC) of 80°C or higher and 180°C or lower, A polyamide resin (B) having a glass transition temperature Tg measured by a differential scanning calorimeter (DSC) of 70°C or lower, A polyamide resin (C) having a heat of fusion in the heating process (heating rate: 10°C / min) measured by a differential scanning calorimeter of 0 J / g or higher and 5 J / g or lower, and a polyamide resin composition containing the same Metal-resin composite.

2. The polyamide resin composition contains glass fibers, and the metal-resin composite according to Claim 1.

3. The polyamide resin (A) is a polyamide resin having a melting point (Tm) measured by a differential scanning calorimeter (DSC) of 280°C or higher and 340°C or lower, The polyamide resin (B) is a polyamide resin having a melting point (Tm) measured by a differential scanning calorimeter (DSC) of less than 280°C, The metal-resin composite according to Claim 1 or 2.

4. The polyamide resin (A) contains a component unit (a1) derived from a dicarboxylic acid and a component unit (a2) derived from a diamine, The component unit (a1) derived from the dicarboxylic acid contains a component unit derived from terephthalic acid in an amount of 20 mol% or more and 100 mol% or less based on the total number of moles of the component unit (a1) derived from the dicarboxylic acid, The component unit (a2) derived from the diamine contains a component unit derived from an aliphatic diamine having 4 to 20 carbon atoms, The metal-resin composite according to any one of Claims 1 to 3.

5. The polyamide resin (A) contains a component unit (a1) derived from a dicarboxylic acid and a component unit (a2) derived from a diamine, The component unit (a1) derived from the dicarboxylic acid contains a component unit derived from terephthalic acid in an amount of 55 mol% or more and 80 mol% or less and a component unit derived from isophthalic acid in an amount of 20 mol% or more and 45 mol% or less based on the total number of moles of the component unit (a1) derived from the dicarboxylic acid, and the metal-resin composite according to any one of Claims 1 to 3.

6. The polyamide resin (A) contains a component unit (a1) derived from a dicarboxylic acid and a component unit (a2) derived from a diamine, The component unit (a2) derived from the diamine includes a component unit derived from 1,6-diaminohexane and a component unit derived from 2-methyl-1,5-diaminopentane. The metal resin composite according to any one of claims 1 to 5.

7. The polyamide resin (B) is a polyamide resin selected from the group consisting of polyamides containing component units derived from nylon 6, nylon 9, nylon 11, nylon 12, nylon 66, nylon 610, nylon 612, and dimer acid. The metal resin composite according to any one of claims 1 to 6.

8. The metal member includes aluminum, copper, and alloys thereof on the joint surface with the polyamide resin composition. The metal resin composite according to any one of claims 1 to 7.

9. A step of preparing a metal member, A step of injecting and solidifying a molten polyamide resin composition onto the surface of the metal member, having, The polyamide resin composition is a polyamide resin (A) having a glass transition temperature Tg measured by a differential scanning calorimeter (DSC) of 80°C or higher and 180°C or lower, a polyamide resin (B) having a glass transition temperature Tg measured by a differential scanning calorimeter (DSC) of 70°C or lower, and a polyamide resin (C) having a heat of fusion in the temperature rising process (heating rate: 10°C / min) measured by a differential scanning calorimeter of 0 J / g or higher and 5 J / g or lower. A method for manufacturing a metal resin composite.

10. A polyamide resin composition for bonding to a metal member, a polyamide resin (A) having a glass transition temperature Tg measured by a differential scanning calorimeter (DSC) of 80°C or higher and 180°C or lower, a polyamide resin (B) having a glass transition temperature Tg measured by a differential scanning calorimeter (DSC) of 70°C or lower, and a polyamide resin (C) having a heat of fusion in the temperature rising process (heating rate: 10°C / min) measured by a differential scanning calorimeter of 0 J / g or higher and 5 J / g or lower. A polyamide resin composition.

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