Metal-resin composite molded product, manufacturing method of metal-resin composite molded product, and processing method of metal member

Abstract

To provide a metal-resin composite molded product in which airtightness of a joint part between a metal member and a polyarylene sulfide-based resin composition member is almost unchanged before and after a heat shock test when the members are joined.SOLUTION: There is provided a metal-resin composite molded product in which a metal member and a polyarylene sulfide-based resin composition member are joined. In the metal-resin composite molded product, spherical metal clusters are substantially formed on a surface portion of one surface of the metal member that is bonded to the polyarylene sulfide-based resin composition member, and an arithmetic mean curvature of an apex of the metal cluster is 3000 to 6000 (1 / mm).SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a technique for joining a metal member and a polyarylene sulfide resin composition. [Background technology]

[0002] By combining materials with different properties, such as electrically conductive materials such as metals and electrically insulating materials such as resins, lightweight, strong, or highly functional parts are being used in a variety of fields. For example, metal-resin composite molded products, which are made by joining metal members with thermoplastic resins, are used in automobile interior components such as console boxes around instrument panels, engine-related parts, interior parts, housings, interface connections, and power terminals for electronic devices such as digital cameras and mobile phones. Generally, bonding and screwing are known as methods for joining different materials such as metal and resin, but these methods are not desirable because they increase the number of processes and parts required. Therefore, various methods for joining metal and resin materials have been proposed.

[0003] For example, Patent Document 1 describes laser processing of the surface of a metal material in one scanning direction, followed by laser processing in another scanning direction intersecting the first scanning direction, and then joining a different material to the surface. Patent Document 2 describes improving the joining strength when joining a resin molded product to the surface by forming irregularities on the surface of a metal plate with a predetermined undercut ratio. Patent Document 3 describes a metal-resin composite molded product in which crater-like depressions are formed in the metal using a laser beam or the like, and granular spatter is formed on the ridge-like protrusions where the metal surface melts and spatters. Patent Document 4 describes a composite structure formed by joining a surface-roughened metal member and a polyarylene sulfide resin composition member, in which the number-average developed area ratio (Sdr) of the interface is 5 or more when any five points on the surface of the surface-roughened metal member are measured using a confocal microscope in accordance with ISO (International Organization for Standardization) 25178, and the melt viscosity of the PPS resin is in the range of 15 to 500 Pa·s. Furthermore, Patent Document 5 discloses a metal insert part and a method for manufacturing a resin molded product using a metal insert part, with the aim of producing an insert mold made of a resin material and a metal material that ensures airtightness and excellent durability. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent No. 4020957 [Patent Document 2] Japanese Patent Publication No. 2020-116806 [Patent Document 3] Japanese Patent Application Laid-Open No. 2013-71312 [Patent Document 4] Patent No. 6819798 [Patent Document 5] Patent No. 6615478 Summary of the Invention [Problem to be solved by the invention]

[0005] However, conventional methods for joining metal and resin materials fail to ensure sufficient airtightness at the joint between the metal and resin materials (i.e., gaps may form at the joint), and improvements to this issue are needed. Furthermore, when metal-resin composite molded products are used in environments with large temperature changes, such as in automobile engine components, problems can arise due to the extremely different expansion and contraction rates (so-called linear expansion coefficients) of resin and metal with temperature changes. For example, when the resin component of a metal-resin composite molded product is thin or has portions with large thickness variations, or when the metal component has sharp corners, temperature changes during use can cause the metal-resin composite molded product to break. As a result, the applications and shapes of metal-resin composite molded products are currently quite limited. Therefore, there is a strong demand for metal-resin composite molded products that can withstand temperature changes over long periods of time. Therefore, the present invention aims to provide a method for manufacturing a metal-resin composite molded article in which a metal member and a polyarylene sulfide-based resin composition member are joined, in which the joint does not lose its airtightness even after a heat shock test, a metal-resin composite molded article manufactured by the method, and a method for processing a metal member. [Means for solving the problem]

[0006] A first aspect of the present invention is a metal-resin composite molded article in which a metal member and a polyarylene sulfide-based resin composition member are bonded together. This metal-resin composite molded article uses a polyarylene sulfide-based resin composition, and substantially spherical metal clusters are formed on one surface of the metal member that is bonded to the polyarylene sulfide-based resin composition member, and the arithmetic mean curvature of the vertices of the metal clusters is 3000 to 6000 (1 / mm).

[0007] A second aspect of the present invention is a method for processing a metal member for producing a metal-resin composite molded product in which the metal member and a polyarylene sulfide-based resin composition member are bonded together. In this processing method, a high-energy beam is irradiated onto the surface of the metal member to form substantially spherical metal clusters on the metal surface, each having an arithmetic mean curvature of 3000 to 6000 (1 / mm).

[0008] A third aspect of the present invention is a method for producing a metal-resin composite molded article in which a metal member and a polyarylene sulfide-based resin composition member are bonded together. In this method, the surface of the metal member is irradiated with a high-energy beam to form substantially spherical metal clusters on the surface of the metal member, the metal clusters having an arithmetic mean curvature of 3000 to 6000 (1 / mm) at their vertices, and the metal member on which the substantially spherical metal clusters have been formed is inserted into a mold. A polyarylene sulfide-based resin composition is then injection-molded to bond the polyarylene sulfide-based resin composition member to the surface of the metal member. [Effects of the Invention]

[0009] According to an aspect of the present invention, the bonded portion of a metal resin composite molded article in which a metal member and a member made of a polyarylene sulfide resin composition are bonded together does not lose airtightness even after a heat shock test. [Brief explanation of the drawings]

[0010] [Figure 1] 1A to 1C are diagrams schematically illustrating a method for processing a metal member according to an embodiment. [Figure 2] 1A and 1B are diagrams showing exemplary metal clusters formed in laser-irradiated portions of a metal member. [Figure 3] FIG. 1 is a diagram illustrating the state of the interface between a metal member and a polyarylene sulfide-based resin composition member in accordance with the size of the Spc on the surface of the polyarylene sulfide-based resin composition member in a metal-resin composite molded product according to one embodiment. [Figure 4] FIG. 2 is a diagram showing the shape of a test piece used in an airtightness test. [Figure 5] FIG. 1 is a diagram showing a schematic configuration of a test device for an airtightness test. DETAILED DESCRIPTION OF THE INVENTION

[0011] Hereinafter, a metal-resin composite molded article according to one embodiment of the present invention will be described. In one embodiment, a metal-resin composite molded article is formed by joining a metal member and a resin composition member, particularly a polyarylene sulfide-based resin composition member. In this metal-resin composite molded article, substantially spherical metal clusters are formed on one surface of the metal member that is joined to the polyarylene sulfide-based resin composition member. The term "substantially spherical" does not necessarily mean that the individual shapes of the metal clusters are perfect spheres, but also includes shapes that are spheroids or shapes in which a portion of a sphere or spheroid is missing. These substantially spherical metal clusters can be formed by, for example, irradiating the surface of a metal member with a laser. As a result of extensive research, the inventors of the present application have discovered that by irradiating the surface of a metal member with a laser under predetermined irradiation conditions, spherical metal clusters can be formed on the metal surface, thereby improving the airtightness of the joint surface between the metal member and the resin composition member of a metal-resin composite molded product after a heat shock test. The shapes of the metal member, the resin composition member, and the metal-resin composite molded product are not particularly limited.

[0012] The metals constituting the metal members contained in the metal-resin composite molded product are not limited to, but include, for example, aluminum, copper, silver, gold, iron, titanium, nickel, magnesium, zinc, and their alloys such as carbon steel and stainless steel. The surface of the metal member may be subjected to a surface treatment such as anodizing or may be painted. From the viewpoint of light weight and strength, it is preferable to use aluminum, magnesium, copper, or titanium as the metal, and in applications requiring conductivity such as terminals, it is more preferable to use aluminum or copper, with copper being particularly preferred. In applications requiring thin-walled rigidity, it is particularly preferable to use magnesium or titanium, and titanium in particular.

[0013] [Polyarylene sulfide resin] The polyarylene sulfide resin (hereinafter sometimes referred to as "PAS resin") used in the polyarylene sulfide resin composition is characterized by excellent mechanical properties, electrical properties, heat resistance, and other physical and chemical properties, as well as good processability. Polyarylene sulfide resin is a polymer compound mainly composed of repeating units -(Ar-S)- (Ar represents an arylene group, and Ar-S represents an arylene sulfide group), and in this embodiment, a polyarylene sulfide resin with a generally known molecular structure can be used.

[0014] Examples of the arylene group include p-phenylene, m-phenylene, o-phenylene, substituted phenylene, p,p'-diphenylenesulfone, p,p'-biphenylene, p,p'-diphenylene ether, p,p'-diphenylenecarbonyl, and naphthalene. The PAS resin may be a homopolymer consisting of the above repeating units, or a copolymer containing the following different repeating units may be preferable in terms of processability.

[0015] As homopolymers, polyphenylene sulfide resins having p-phenylene groups as the arylene group and p-phenylene sulfide groups as repeating units are preferably used. Furthermore, as copolymers, copolymers composed of a combination of two or more different arylene sulfide groups containing the above-mentioned arylene groups can be used. Among these, copolymers composed of a combination of p-phenylene sulfide groups and m-phenylene sulfide groups are particularly preferred. Among these copolymers, those containing 70 mol % or more, preferably 80 mol % or more, of p-phenylene sulfide groups are suitable in terms of physical properties such as heat resistance, moldability, and mechanical properties. Furthermore, among these polyarylene sulfide resins, high-molecular-weight polymers with a substantially linear structure (e.g., poly-p-phenylene sulfide) obtained by condensation polymerization of monomers mainly composed of bifunctional halogenated aromatic compounds are particularly preferred. The polyarylene sulfide resin used in this embodiment may be a mixture of two or more polyarylene sulfide resins having different molecular weights.

[0016] In addition to the linear polyarylene sulfide resin, a polymer can be used in which a small amount of a monomer such as a polyhaloaromatic compound having three or more halogen substituents is used during condensation polymerization to form a partially branched or crosslinked structure. Also used is a polymer in which a low-molecular-weight linear polymer is heated at high temperature in the presence of oxygen or the like to increase the melt viscosity through oxidative crosslinking or thermal crosslinking, thereby improving moldability. In the present embodiment, the polyarylene sulfide resin composition refers to a composition containing one or more of the above polyarylene sulfide resins and other additives that may be added as needed.

[0017] [Olefin copolymer] In this embodiment, an olefin copolymer may be added to the polyarylene sulfide resin composition to improve the bonding between a metal member and a polyarylene sulfide resin composition member. The olefin copolymer contains an α-olefin, a glycidyl ester of an α,β-unsaturated acid, and a (meth)acrylic acid ester as copolymerization components. First, the essential copolymerization components will be described.

[0018] In the present invention, the α-olefin is not particularly limited, and conventionally known α-olefins can be used. For example, ethylene, propylene, butylene, etc. are usable. Among these α-olefins, ethylene is particularly preferred. Two or more of these α-olefins can also be used in combination.

[0019] The glycidyl ester of an α,β-unsaturated acid is a component represented by the following general formula (1). [ka] (R1 in formula (1) represents hydrogen or a lower alkyl group.)

[0020] Examples of the compound represented by the general formula (1) include glycidyl acrylate, glycidyl methacrylate, glycidyl ethacrylate, etc. In the present invention, it is preferable to use glycidyl methacrylate.

[0021] The inclusion of a glycidyl ester of an α,β-unsaturated acid as a copolymerization component improves bonding with metals. However, as the content of the copolymerization component derived from the glycidyl ester increases, the problem of mold deposits becomes more pronounced. Traditionally, mold deposits have been thought to be caused by thermal degradation of thermoplastic elastomers such as olefin copolymers at high temperatures. However, in the case of an olefin copolymer containing an α-olefin and a glycidyl ester of an α,β-unsaturated acid as copolymerization components, the problem of mold deposits can be reduced even when using an olefin copolymer by reducing the amount of glycidyl ester of an α,β-unsaturated acid used.

[0022] The acrylic acid ester usable in the embodiment is not particularly limited, and conventionally known acrylic acid esters can be used. Examples of usable acrylic acid esters include methyl acrylate, ethyl acrylate, n-propyl acrylate, isopropyl acrylate, n-butyl acrylate, n-hexyl acrylate, and n-octyl acrylate, as well as methacrylic acid and methacrylic acid esters (e.g., methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, isopropyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, n-amyl methacrylate, and n-octyl methacrylate). Among these acrylic acid esters, methyl acrylate is particularly preferred.

[0023] The olefin copolymer used in the embodiment may contain other copolymer components within the range that does not impair the effects of the present invention.

[0024] The olefin copolymer used in the embodiment can be produced by polymerization using a conventionally known method.

[0025] The content of the olefin copolymer contained in the composition of the present invention is not particularly limited. In an embodiment, the olefin copolymer is preferably contained in an amount of 0 to 20 parts by mass, more preferably 1% by mass or more and 15% by mass or less, relative to 100 parts by mass of the polyarylene sulfide resin.

[0026] [Inorganic filler] The resin composition of the present invention can contain inorganic fillers to improve properties such as mechanical strength, heat resistance, dimensional stability (resistance to deformation and warpage), and electrical properties. Depending on the purpose, inorganic fillers may be used in the form of fibrous, powdery, or plate-like fillers. Examples of fibrous fillers include inorganic fibrous materials such as glass fiber, asbestos fiber, carbon fiber, silica fiber, silica-alumina fiber, zirconia fiber, boron nitride fiber, boron fiber, potassium titanate fiber, and metal fibrous materials such as stainless steel, aluminum, titanium, copper, and brass. Particularly representative fibrous fillers are glass fiber and carbon fiber. On the other hand, examples of powdery fillers include carbon black, silica, quartz powder, glass beads, glass powder, calcium silicate, aluminum silicate, kaolin, talc, clay, diatomaceous earth, silicates such as wollastonite, metal oxides such as iron oxide, titanium oxide, zinc oxide, and alumina, metal carbonates such as calcium carbonate and magnesium carbonate, metal sulfates such as calcium sulfate and barium sulfate, silicon carbide, silicon nitride, boron nitride, and various metal powders. Examples of plate-like fillers include mica, glass flakes, and various metal foils. In an embodiment, the use of glass fiber, calcium carbonate, and glass beads, or a combination of these, is preferred. These inorganic fillers can be used alone or in combination of two or more.

[0027] In the embodiment, the content of the inorganic filler is preferably 0 to 80 parts by mass, more preferably 0 to 75 parts by mass, relative to 100 parts by mass of the polyarylene sulfide resin. If the content of the inorganic filler is more than 75 parts by mass, the melt viscosity of the polyarylene sulfide resin composition increases, and the polyarylene sulfide resin may not fill the metal clusters on the surface of the metal member, and airtightness between the metal member and the polyarylene sulfide resin composition member may not be obtained.

[0028] [Other ingredients] The polyarylene sulfide resin composition used in the embodiment may contain other resins as long as the effects of the present invention are not impaired. The polyarylene sulfide resin composition used in the present invention also includes compositions to which desired properties have been imparted by adding a nucleating agent, a pigment such as carbon black or an inorganic calcined pigment, an antioxidant, a stabilizer, a plasticizer, a lubricant, or a mold release agent in order to impart desired properties to a molded article.

[0029] [Polyarylene sulfide resin composition] The polyarylene sulfide resin composition of the embodiment can be prepared by a conventionally known method, such as a method of mixing the components and then kneading and extruding them in an extruder to prepare pellets, a method of first preparing pellets with different compositions, mixing a predetermined amount of the pellets, and molding them to obtain a molded product with the desired composition, or a method of directly charging one or more of the components into a molding machine.

[0030] The method for joining the metal member and the polyarylene sulfide-based resin composition member will be described in detail below, but is not particularly limited. For example, they can be joined by a welding method such as ultrasonic welding, vibration welding, or laser welding, or by injection molding. For example, joining is preferably performed by insert molding using a metal material as an insert member. The metal member used in the embodiment and a processing method therefor will be described later. In one embodiment, it is preferable that substantially spherical metal clusters are present on the surface portion of one surface of the metal member that is joined to the polyarylene sulfide-based resin composition member, as described above. The arithmetic mean curvature of the vertices of the metal clusters is preferably 3000 to 6000 (1 / mm). The arithmetic mean curvature of the vertices of the metal clusters will be described in detail below. In one embodiment, the metal-resin composite molded article is characterized in that the airtightness of the joint between the metal member and the polyarylene sulfide resin composition member is approximately the same before and after 1,000 cycles of a heat shock test, in which one cycle consists of leaving the material at a temperature of -40°C for 30 minutes and leaving the material at a temperature of 150°C for 30 minutes. The heat shock test, also known as a thermal shock test, is a test in which a material is repeatedly subjected to rapid temperature changes, causing it to expand and contract, thereby generating thermal stress and thermal distortion within the material, and observing whether defects such as cracks occur in the material. The Japanese Industrial Standards (JIS) specifies the test method in JIS C 60068-2-14(Na) (Environmental Testing Methods - Electrical and Electronic). In one embodiment, a metal-resin composite molded article is repeatedly subjected (for example, 1,000 cycles) to a heat shock test in which one cycle is left at -40°C for 30 minutes and then left at 150°C for 30 minutes. The test is then observed to determine whether or not any defects occur in the airtightness of the joint between the metal member and the polyarylene sulfide-based resin composition member. The airtightness of the joint between the metal member and the polyarylene sulfide-based resin composition member is essentially the same before and after the heat shock test. Here, the airtightness of the joint between the metal member and the polyarylene sulfide-based resin composition member simply refers to the presence or absence of gaps at the joint between the metal member and the polyarylene sulfide-based resin composition member. If gaps that were not present before the heat shock test are observed to appear after the heat shock test, the airtightness is evaluated as having decreased. The phrase "the airtightness of the joint between the metal member and the polyarylene sulfide-based resin composition member is essentially the same before and after the heat shock test" means that the airtightness remains unchanged and that the degree of increase or decrease in airtightness is minimal. Here, the airtightness of the joint between the metal member and the polyarylene sulfide-based resin composition member is measured by using a dedicated measuring device such as an airtightness measuring device to flow a predetermined gas at a specific detection pressure and detect gas leaking from the joint. The airtightness of the joint between the metal member and the polyarylene sulfide-based resin composition member can be measured, for example, by a helium leak test vacuum method or the like.

[0031] A second embodiment of the present invention is a method for processing a metal member for producing a metal-resin composite molded product in which a metal member and a polyarylene sulfide-based resin composition member are joined together. Fig. 1 shows a schematic diagram of the method for processing a metal member according to the second embodiment. As shown in Figure 1, when a metal component is irradiated with a laser, the metal on the component's surface is melted by the high-energy laser beam, pushed out of the irradiated area, and then solidified into a spherical shape due to surface tension. The surface of the metal component is scanned with the laser at a minute pitch, generating spherical objects that overlap to form metal clusters. Alternatively, the metal component sublimes, and the scattered liquid metal particles solidify (re-adhere) and accumulate, forming spherical metal clusters. Figure 2 shows an example image of a metal cluster formed in the laser-irradiated area when a metal component is irradiated with a laser. Here, if the laser output (energy per unit time) is low, the metal on the metal surface may not melt, or sublimation or scattering of liquid metal particles may not occur. Therefore, the laser output for forming spherical metal clusters is determined appropriately depending on the metal material used for the metal component. Furthermore, to make the molten metal extruded outside the laser irradiation area into tiny spheres, the laser scanning pitch is preferably 30 μm or less, more preferably 20 μm or less, or even 10 μm or less. The laser output and irradiation speed determine the energy applied to the metal surface per unit area per unit time. Therefore, in addition to the laser output, the irradiation speed is also a factor in forming spherical metal clusters. Appropriate laser output and irradiation speed cause a local temperature rise on the metal surface in an extremely short time, thereby forming spherical metal clusters. Using the metal member processing method of the second embodiment, substantially spherical metal clusters can be formed on the surface portion of one surface of the metal member used in the metal-resin composite molded product of the first embodiment that is to be joined to the polyarylene sulfide-based resin composition member.

[0032] From the viewpoint of ensuring sufficient airtightness of the joint surface between the metal member and the polyarylene sulfide-based resin composition member, it is preferable that spherical metal clusters are formed over the entire joint surface between the metal member and the polyarylene sulfide-based resin composition member. To achieve this, it is advisable to make the laser scanning pitch smaller than the laser irradiation diameter.

[0033] In this disclosure, the term "high energy beam" means a beam with energy per unit time high enough to form spherical metal clusters on the surface of a metal member. The high energy beam is typically, but not necessarily, a laser, and may be a beam generated by an electron gun. In the second embodiment, it is preferable to form substantially spherical metal clusters on the surface of the metal member by irradiating the surface of the metal member with a high-energy beam, the metal clusters having an arithmetic mean curvature of the vertices of the metal clusters being 3000 to 6000 (1 / mm). The arithmetic mean curvature of the vertices of the metal clusters will be described in detail later.

[0034] A third embodiment is a method for producing a metal-resin composite molded article in which a metal member and a polyarylene sulfide-based resin composition member are joined. The method for producing a metal-resin composite molded article of the third embodiment is a method for forming substantially spherical metal clusters on the surface of the metal member by irradiating the surface of the metal member with a high-energy beam such as a laser, and then melt-joining the metal member on which the substantially spherical metal clusters have been formed and the polyarylene sulfide-based resin composition member. By forming spherical metal clusters at the joint surface between a metal member and a polyarylene sulfide-based resin composition member, when the metal member and the polyarylene sulfide-based resin composition member are insert-molded, the molten polyarylene sulfide-based resin composition penetrates into the spherical metal clusters, thereby improving adhesion between the metal and the polyarylene sulfide-based resin composition during the molding stage. As a result, the produced metal-resin composite molded product achieves higher airtightness than conventional at the joint surface between the metal member and the polyarylene sulfide-based resin composition member.

[0035] The area where the spherical metal clusters are formed on the surface of the metal member is preferably the entire surface of the joint surface between the metal member and the polyarylene sulfide-based resin composition member, but is not limited to this. For example, if the spherical metal clusters are formed over most of the joint surface, for example, over 70 to 80% or more of the joint surface, a sufficiently high level of airtightness can be ensured at the joint surface between the metal member and the polyarylene sulfide-based resin composition member. For example, when the entire joining surface between a metal member and a polyarylene sulfide-based resin composition member is irradiated with a laser, if the laser scanning pitch is larger than the laser irradiation diameter, there will be areas on the joining surface that are not irradiated with the laser. Even in this case, if the areas on the joining surface that are not irradiated with the laser are relatively small, a sufficiently high level of airtightness will be ensured at the joining surface between the metal member and the polyarylene sulfide-based resin composition member.

[0036] The present inventors further focused on the shape of spherical metal clusters formed on the surface of a metal member and conducted research into the relationship between various surface roughness parameters of the metal member surface and the airtightness of the joint surface between the metal member and a polyarylene sulfide-based resin composition member. As a result, they found that by setting the Spc (arithmetic mean curvature of peaks) of the apexes of the spherical metal clusters within a predetermined range, the airtightness of the joint surface between the metal member and the polyarylene sulfide-based resin composition member can be maintained at a good level even after a heat shock test. Spc (arithmetic mean curvature of peaks) is a surface texture parameter defined in ISO 25178 and represents the average value of the principal curvatures of the peaks formed on the surface to be evaluated. A small Spc indicates that the point (peak) that comes into contact with another object (in this embodiment, a polyarylene sulfide-based resin composition member) is rounded, while a large Spc indicates that the point that comes into contact with another object is sharp.

[0037] The reason why the airtightness of the joint surface between the metal member and the resin remains almost the same before and after the heat shock test when the Spc of the apex of the spherical metal cluster is set within a predetermined range can be inferred as follows, referring to Figure 3. FIG. 3 is a schematic diagram showing the bonded surface between a metal member and a polyarylene sulfide-based resin composition member when the Spc of the vertices of the spherical metal clusters formed on the surface of the metal member is large ("large Spc"), medium ("medium Spc"), or small ("small Spc"). When the Spc on the surface of the metal member is large, the vertices of the spherical metal clusters have a sharp shape. When the polyarylene sulfide-based resin composition in contact with this surface cools, sink marks (shrinkage) occur. However, if the vertices of the metal clusters have a sharp shape, gaps are likely to form between the polyarylene sulfide-based resin composition and the metal at the bonded surface of the vertices, which is disadvantageous in terms of achieving high airtightness. On the other hand, when the Spc on the surface of the metal member is small, the spherical metal clusters have a surface texture that changes gradually overall. The surface area of ​​the joint between the metal member and the polyarylene sulfide-based resin composition member is small, making it difficult to achieve high adhesion between the metal member and the polyarylene sulfide-based resin composition member during the molding stage of a metal-resin composite molded product. Therefore, when the Spc on the surface of the metal member is moderate, the molten polyarylene sulfide-based resin composition penetrates sufficiently into the spherical metal clusters on the surface of the metal member, allowing the fine clusters on the surface of the metal member to form many anchors with the resin. Therefore, loosening of the joint (leak paths) due to expansion and contraction of the resin during a heat shock test is unlikely to occur, and it is presumed that the adhesion between the metal member and the polyarylene sulfide-based resin composition member of the metal-resin composite molded product can be maintained extremely high even after the heat shock test.

[0038] Specifically, the Spc of the apex of the spherical metal cluster on the surface of the metal member is preferably in the range of 3000 to 6000 (1 / mm), and more preferably in the range of 4500 to 4700 (1 / mm). To adjust this Spc to fall within the desired range, the energy applied by laser irradiation to the surface that will become the joining interface between the metal member and the polyarylene sulfide-based resin composition member is controlled. When a pulsed laser is used as the laser, the energy E per pulse is expressed as P / f, where P is the average output and f is the frequency. Therefore, by adjusting the average output P (i.e., laser output) and / or the frequency f, the energy applied to the surface that will become the joining interface between the metal member and the polyarylene sulfide-based resin composition member can be controlled. For example, increasing the frequency of the pulsed laser reduces the amount of energy per pulse applied to the surface of the metal member, which tends to decrease Spc. Conversely, decreasing the frequency of the pulsed laser increases the amount of energy per pulse applied to the surface of the metal member, which tends to increase Spc, but once the amount of energy is sufficiently large, Spc saturates.

[0039] The particle size of the particles constituting the metal clusters is preferably 1 to 500 μm, more preferably 5 to 300 μm, and particularly preferably 10 to 200 μm. If the particle size is less than 1 μm, the polyarylene sulfide resin may not fill the gaps between the particles constituting the resin clusters, resulting in poor adhesion. If the particle size exceeds 500 μm, shrinkage of the polyarylene sulfide resin after molding may cause gaps between the resin and the metal member, resulting in poor airtightness.

[0040] The method for joining a metal member and a polyarylene sulfide-based resin composition member is not limited, and they can be joined by welding methods such as ultrasonic welding, vibration welding, and laser welding, or by injection molding. For example, they can be joined by insert molding using a metal material as an insert member. That is, a metal member having spherical metal clusters formed on its surface as described above is inserted into a mold, and a polyarylene sulfide-based resin composition is injected into the mold, and these are molded together to join the polyarylene sulfide-based resin composition member to the surface of the metal member. [Example]

[0041] [Manufacturing of metal-resin composite molded products] The production of a metal-resin composite molded product will be specifically described below. In the examples, a metal-resin composite molded article 10 (hereinafter referred to as "test piece 10") having the shape shown in FIG. 4 was prepared as a test piece. As shown in Fig. 4, the test piece 10 consisted of a circular metal member 11 having an inner hole in the center and a resin molded product 12 placed in the inner hole of the metal member 11. The metal member 11 had an outer diameter of φ50 mm, an inner hole diameter of φ20 mm, and a thickness of 1 mm. The resin molded product 12 had an outer diameter of φ30 mm and a thickness of 3 mm.

[0042] The components used in the materials constituting the metal member 11 and the resin molded product 12 are as follows: Metal parts: Aluminum A5052 Polyarylene sulfide resin composition: Polyarylene sulfide resin 1: Fortron KPS manufactured by Kureha Corporation (melt viscosity: 20 Pa·s (shear rate: 1200 sec) -1 , 310℃) Polyarylene sulfide resin 2: Fortron KPS manufactured by Kureha Corporation (melt viscosity: 28 Pa·s (shear rate: 1200 sec -1 , 310℃) Polybutylene terephthalate resin: Polyplastics Co., Ltd. "300FP" Polyethylene terephthalate resin: "PET II" manufactured by Takayasu Co., Ltd. Olefin copolymer 1: "Bondfast 7L" manufactured by Sumitomo Chemical Co., Ltd. Olefin copolymer 2: "Bondfast 7M" manufactured by Sumitomo Chemical Co., Ltd. Glass fiber 1: Owens Corning Manufacturing Co., Ltd. "CS GL-HF" Glass fiber 2: Nippon Electric Glass Co., Ltd. "ECS03T747" Glass fiber 3: Nippon Electric Glass Co., Ltd. "ECS03T747H" Glass fiber 4: Nippon Electric Glass Co., Ltd. "ECS03T187" Calcium carbonate: Asahi Komatsu Co., Ltd. "MC-35W" Carbon black: "MA600B" manufactured by Mitsubishi Chemical Corporation Pentaerythritol stearate: Emery Oleochemicals Japan LOXYOL VPG861 Antioxidant: "Irganox 1010" manufactured by BASF Japan Ltd. Phosphorus stabilizer: Monocalcium phosphate manufactured by Taihei Chemical Industry Co., Ltd. The component ratios of the polyarylene sulfide resin compositions used as materials for resin molded articles are shown in Table 1. The melt viscosities of the polyarylene sulfide resin compositions shown in Table 1 were measured in accordance with ISO 11433 as follows. A Capillograph manufactured by Toyo Seiki Seisakusho Co., Ltd. was used, and a flat die of 1 mm diameter x 20 mm length was used as the capillary. The barrel temperature was 310°C, and the shear rate was 1000 sec. -1 The melt viscosity was measured under the following conditions.

[0043] [Table 1]

[0044] Before joining with the resin molded product 12, a laser processing machine (ML-7350DL manufactured by Amada Weld Tech) was used to perform concentric laser processing on the surface of the metal member 11 in the range of φ20 mm to φ26 mm (the joining surface with the resin molded product 12). Table 2 below shows the laser irradiation conditions for Examples 1 and 2 and Comparative Examples 1 and 2. Although not shown in the table, the laser irradiation pitch was 10 μm and the irradiation diameter was 58 μm for all Examples and Comparative Examples. The pitch is the distance between concentric circles scanned by the laser. Because the pitch is smaller than the irradiation diameter, the entire joining surface between the metal member 11 and the resin molded product 12 is irradiated with the laser.

[0045] In all examples and comparative examples, the surface of the metal member 11 was observed with a scanning electron microscope (SEM), and it was confirmed that spherical metal clusters were formed over the entire surface. Furthermore, the Spc of the apex of the spherical metal clusters formed on the surface of the metal member 11 was measured using a laser microscope VK-X3000 manufactured by Keyence Corporation (see Table 2).

[0046] After laser processing of the metal member 11, insert molding was performed under the following conditions using the metal member 11 as an insert member and each material listed in Table 1 as a resin composition, and the metal member 11 and the resin molded product 12 were joined to form a test piece 10 of a metal-resin composite molded product shown in Figure 4. The insert molding conditions were as follows: Injection molding machine: Sodick TR100EH Cylinder temperature: 320°C (Examples 1 to 3) 260°C (Comparative Examples 1 and 2) Mold temperature: 150°C (Examples 1 to 3) 150°C (Comparative Examples 1 and 2) ·Injection speed: 15mm / s - Holding pressure: 50MPa

[0047] [Airtightness test] Next, for the test pieces 10 molded as the examples and comparative examples, an airtightness test was conducted on the joint surface between the metal member 11 and the resin molded article 12. The configuration of the test equipment for the airtightness test (helium leak test, vacuum method) is shown in FIG. As shown in Figure 5, a jig 2 and a test piece 10 were placed in a chamber 3 that was sealed from the outside. The jig 2 was a rectangular parallelepiped with a bottom, and by placing the test piece 10 on top, the inside of the jig 2 was sealed from the rest of the chamber 3. With a valve 6 in the open position, a vacuum was created inside the jig 2 using a vacuum pump 5. Next, with the valve 6 in the closed position, the chamber 3 was filled with helium gas using a helium cylinder 4. Helium gas leaking from the joint of the test piece 10 inside the chamber 3 was detected by a helium detector 7. A control device 8 displayed the helium gas detection results. As the helium detector 7, a helium leak tester G-FINE manufactured by Cosmo Instruments Co., Ltd. and an L300i manufactured by Inficon Co., Ltd. were used.

[0048] The helium pressure in the chamber 3 was set to 400 kPa, and the vacuum pressure in the jig 2 was set to 100 kPa. If the airtightness of the joint between the metal member 11 and the resin molded product 12 of the test piece 10 is low, the helium gas in the chamber 3 will flow into the jig 2 and be detected by the helium detector 7. In this test, the helium pressure (detection pressure) detected by the helium detector 7 was 1.0 × 10 -7 (In the table, this is written as "1.0E-7") Pa·m 3 / s or more is judged to be poor airtightness, and -7 (1.0E-7)Pa·m 3 If the value was less than / s, the airtightness was judged to be good.

[0049] [Heat shock test] Heat shock tests were conducted using thermal shock testers ES-106LH and ES-77LHS manufactured by Hitachi Appliances, Inc. For Examples 1 to 3, one cycle consisted of leaving the molded resin article at -40°C for 30 minutes and leaving it at 150°C for 30 minutes. Every 250 cycles, the molded resin article was removed from the chamber and subjected to the airtightness test described above to evaluate its thermal shock resistance (heat shock resistance). For Comparative Examples 1 and 2, one cycle consisted of leaving the molded resin article at -40°C for 30 minutes and leaving it at 125°C for 30 minutes. Every 250 cycles, the molded resin article was removed from the chamber and subjected to the airtightness test described above to evaluate its thermal shock resistance. Each heat shock test was conducted up to 1,000 cycles. Table 2 shows the results of Examples 1 to 3 and Comparative Examples 1 and 2 regarding the pressure detected in the airtightness test on the test specimen.

[0050] [Table 2]

[0051] Table 2 confirms that when the Spc of the apex of the metal cluster of the metal member in a composite molded product of a polyarylene sulfide-based resin composition member and a metal member is 4500 to 4700 (1 / mm), the joint between the metal member and the polyarylene sulfide-based resin composition member remains highly airtight even after the heat shock test.Comparative Examples 1 and 2 show that even when the Spc of the metal member is within the above range, in a composite molded product of a polybutylene terephthalate-based resin composition member and a metal member, the resin molded product cracked and broke, and the joint could not remain airtight after the heat shock test.

[0052] Although the embodiments of the present invention have been described in detail above, the present invention is not limited to the above-described embodiments. Furthermore, the above-described embodiments can be improved or modified in various ways without departing from the spirit of the present invention. [Explanation of symbols]

[0053] 2...Jig 3...Chamber 4...Helium tank 5...Vacuum pump 6...Valve 7...Helium detector 8...Control device 10…Metal resin composite molded product 11...Metal parts 12…Resin molded product

Claims

1. A metal-resin composite molded product in which a metal member and a polyarylene sulfide-based resin composition member are joined, a surface portion of one surface of the metal member that is bonded to the polyarylene sulfide resin composition member has substantially spherical metal clusters; the arithmetic mean curvature of the vertices of the metal clusters is 3000 to 6000 (1 / mm); A metal-resin composite molded product in which the airtightness of the joint between the metal member and the polyarylene sulfide-based resin composition member is substantially the same before and after 1,000 cycles of a heat shock test, one cycle of which is leaving the product at a temperature of -40°C for 30 minutes and leaving the product at a temperature of 150°C for 30 minutes.

2. 2. The metal-resin composite molded product according to claim 1, wherein the arithmetic mean curvature of the vertices of the metal clusters is 4000 to 5000 (1 / mm).

3. A method for producing a metal-resin composite molded product in which a metal member and a polyarylene sulfide-based resin composition member are joined, comprising: Irradiating a surface of the metal member with a high-energy beam to form substantially spherical metal clusters on the surface of the metal member, the metal clusters having an arithmetic mean curvature of vertices of 3000 to 6000 (1 / mm); the metal member having the substantially spherical metal clusters formed on the surface thereof is inserted into a mold, and a polyarylene sulfide-based resin composition is injection-molded to bond the polyarylene sulfide-based resin composition member to the surface of the metal member; Manufacturing method for metal-resin composite molded products.

4. The method for producing a metal-resin composite molded product according to claim 3, wherein the arithmetic mean curvature of the vertices of the metal clusters is 4000 to 5000 (1 / mm).

5. A method for processing a metal member for producing a metal-resin composite molded product in which a metal member and a polyarylene sulfide-based resin composition member are joined, comprising: A method for processing a metal member, comprising irradiating a surface of the metal member with a high-energy beam to form substantially spherical metal clusters on the surface of the metal member, the metal clusters having arithmetic mean curvatures of vertices of 3000 to 6000 (1 / mm).

6. 6. The method for processing a metal member according to claim 5, wherein the arithmetic mean curvature of the vertices of the metal clusters is 4000 to 5000 (1 / mm).

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