Foam resin-metal composite body and metal resin composite member

Abstract

To provide a foam resin-metal composite body which is lightweight and is excellent in bending strength.SOLUTION: A foam resin-metal composite body 10 has a foam resin body 2 and a metal body 1, wherein the metal body has a recess 3 that partially surrounds and comes in contact with the foam resin body and does not reach the metal body, on an exposure surface to which the foam resin body is exposed.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present disclosure relates to a foamed resin-metal composite and a metal-resin composite member. [Background technology]

[0002] Composite materials that secure desired mechanical properties or functionality by compounding and integrating two or more kinds of materials have been variously studied from the viewpoints of weight reduction and functionality of parts in each technical field. For example, it has been proposed to use a metal-resin composite in which a metal plate is reinforced with a resin material as a vehicle frame member or a building member (see Patent Documents 1 and 2). For example, Patent Document 1 discloses a method in which a polymerized steel plate having a foamable material attached to the surface of the steel plate is formed, and then the polymerized steel plate is heated to form a foam layer by foaming the foamable material, and the steel plate and the foam layer are bonded together at the same time. Patent Document 2 discloses a technique for bonding a thermoplastic polyester resin to a magnesium plate. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 9-164541 [Patent Document 2] JP 2020-151981 A Summary of the Invention [Problem to be solved by the invention]

[0004] However, in the technology of Patent Document 1, although the manufacturing efficiency of the vibration-damping polymerized steel plate with a foam layer and suppression of defects such as crushing and breaking of the foam layer are considered, the morphology of the foam layer and mechanical strength such as bending strength are not considered at all. Also, in the technology of Patent Document 2, although the adhesion between the thermoplastic polyester resin and the magnesium plate is considered, the morphology of the foam layer and mechanical strength such as bending strength are not considered at all. Therefore, an object of the present invention is to provide a foamed resin-metal composite that is lightweight and has excellent bending strength, and a metal-resin composite member that includes the foamed resin-metal composite. [Means for solving the problem]

[0005] In view of the above problems, the present inventors have conducted intensive research and repeated experiments, and as a result, have found that the above problems can be solved by using a metal resin composite in which a foamed resin having a specific recess shape is covered with a metal body so as to expose the recess, and a metal resin composite member including the foamed resin-metal composite, and have thus completed the present invention. That is, the present invention is as follows.

[0006] [1] The present disclosure relates to a foamed resin-metal composite having a foamed resin body and a metal body, the metal body partially surrounding and closely adhering to the foamed resin body, and a recess in which the metal body does not reach an exposed surface of the foamed resin body.

[0007] [2] The foamed resin-metal composite according to [1], comprising: a resin columnar body which is the foamed resin body; the metal body which covers the columnar body so that a portion of a side surface of the columnar body is exposed and is in close contact with the columnar body; and the recess which is recessed into the exposed surface.

[0008] [3] The foamed resin-metal composite according to [1] or [2], wherein the foamed resin contains a polyamide resin.

[0009] [4] The foamed resin-metal composite according to any one of [1] to [3], wherein the number of the recesses formed on the exposed surface is within a range of 1 to 100 per meter.

[0010] [5] The foamed resin-metal composite material according to any one of [1] to [4], wherein the recesses are recessed into the exposed surface in a lattice pattern.

[0011] [6] A foamed resin-metal composite according to any one of [1] to [5], comprising: a resin foamed resin body (2) that is a rectangular prism-shaped body; a metal body that covers the rectangular prism-shaped body so that one of the four side surfaces of the rectangular prism-shaped body is entirely exposed and is in close contact with the rectangular prism-shaped body; and a recess that is recessed into the exposed surface.

[0012] [7] A metal resin composite member comprising: the foamed resin-metal composite according to any one of [1] to [6]; and a substrate attached so as to cover an exposed surface of the foamed resin. Effect of the Invention

[0013] According to the present invention, it is possible to provide a foamed resin-metal composite that is lightweight and has excellent bending strength, and a metal resin composite member that includes the foamed resin-metal composite. [Brief description of the drawings]

[0014] [Figure 1] FIG. 1 is a perspective view showing an example of a foamed resin-metal composite body of the present embodiment. [Diagram 2] FIG. 2 is a perspective view showing another example of the foamed resin-metal composite body of the present embodiment. [Diagram 3] FIG. 3 is a diagram showing an example of a metal body used in the foamed resin-metal composite body of this embodiment. [Figure 4] FIG. 4 is a diagram showing an example of the foamed resin body (1) in the foamed resin-metal composite (1) of this Example 1, in which the dashed circle portions represent the first and second holes into which a penetrating shaft means such as a rivet is inserted. [Diagram 5] FIG. 5 is a diagram showing an example of bonding between a foamed resin-metal composite of this embodiment and a substrate, in which the solid and dashed "circle" portions represent first and second holes into which penetrating shaft means such as rivets are inserted. [Figure 6]Fig. 6 is a photograph showing a preferred embodiment of the foamed resin-metal composite of this embodiment. Fig. 6(1) shows a foamed resin body with a sun-shaped recess, Fig. 6(2) shows a foamed resin body with a square-shaped recess, Fig. 6(3) shows a foamed resin body without a recess, and Fig. 6(4) shows a foamed resin body without a recess. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0015] Hereinafter, an embodiment of the present invention (hereinafter referred to as "the present embodiment") will be described in detail, but the present invention is not limited to the following description and can be practiced with various modifications within the scope of the gist. In addition, in this embodiment, A (number) to B (number) means A or more and B or less.

[0016] [Polymer-metal composite] This embodiment is a foamed resin-metal composite having a foamed resin body 2 and a metal body, the metal body partially surrounding and adhering to the foamed resin body 2, and a recessed portion that does not reach the metal body on the exposed surface where the foamed resin body 2 is exposed. That is, the foamed resin-metal composite of this embodiment has a structure in which the foamed resin body 2 and the metal body are in close contact with each other so that a part of the foamed resin body 2 is exposed, and the foamed resin body 2 is covered by the metal body. In addition, the exposed surface where a part of the foamed resin body 2 is exposed has a structure in which a recessed portion is provided with a depth such that the metal body is not exposed. Therefore, the composite is lightweight and can exhibit excellent bending strength. Here, the metal body being "adhered" to the foamed resin body refers to a state in which the metal body and the foamed resin body are in physical contact with each other, and is not necessarily limited to a state in which they are bonded with an adhesive or the like.

[0017] Hereinafter, the present embodiment will be described by way of example with reference to the drawings. 1 and 2, in one embodiment of the present invention, a resin foam-metal composite 10 has a structure in which a resin foam 2 is tightly coated on a metal body 1 so that a part of the resin foam 2 is exposed, and the exposed surface of the resin foam 2 where a part of the resin foam 2 is exposed has a recess 3. Therefore, it is considered that high bending strength can be exhibited by suppressing deformation in the torsional direction of the metal. Therefore, the resin foam-metal composite 10 of this embodiment can be used as a vibration damping material, a vehicle bumper, a vehicle pillar, or other automotive structural member, and the like.

[0018] A foamed resin-metal composite 10 has a metal body 1 and a foamed resin body 2. As an example of this embodiment, a foamed resin-metal composite 10 having a long metal body 1 (a so-called gutter-shaped metal body 1) with a groove having a rectangular cross section, a quadrangular columnar foamed resin body 2 provided in the rectangular groove in close contact with the metal body 1 and partially exposed from the opening of the groove, and a plurality of rectangular parallelepiped recesses 3 provided on the exposed surface of the foamed resin body 2 will be described with reference to Fig. 1. The rectangular columnar foamed resin body 2 is surrounded by the metal body 1 so that one of the four side surfaces of the rectangular columnar foamed resin body 2 is entirely exposed, and the rectangular columnar foamed resin body 2 and the metal body 1 are in close contact with each other. A recess 3 is provided in the exposed surface where one of the side surfaces of the rectangular columnar foamed resin body 2 is entirely exposed. The depth of the recess 3 is a range that does not reach the metal body 1, that is, a range where the surface of the metal body 1 is not exposed. Therefore, the bottom of the recess 3 is covered with the foamed resin body 2 (not shown). The long metal body 1 having a groove with a rectangular cross section in FIG. 1 has both ends open, and there are exposed surfaces at both ends where the foamed resin body 2 is exposed. It is believed that by closely surrounding the foamed resin body 2 on a total of three surfaces, namely the bottom and side surfaces, of the long metal body 1 having a groove with a rectangular cross-section, torsional deformation of the metal is suppressed, thereby enabling the material to exhibit high bending strength.

[0019] 1, a pair of flanges 4a, 4b are provided along the longitudinal direction of the metal body 1. By providing these flanges, they can function as joints with other members. One or more flange portions 4a, 4b may be provided depending on the mode of use or the shape of metal body 1. For example, when metal body 1 is helmet-shaped or bowl-shaped with a polygonal bottom, one of flange portions 4a or 4b may be provided along the outer periphery of the opening of the helmet or bowl shape. Flange portion 4a or flange portion 4b in Fig. 1 may be provided, for example, by folding the edge of band-shaped flat metal body 1 so that a specified excess is left.

[0020] Next, in FIG. 2, as another example of this embodiment, a foamed resin-metal composite 10 having a long metal body 1 (a so-called gutter-shaped metal body 1) with a groove having a rectangular cross section, a quadrangular columnar foamed resin body 2 provided in the rectangular groove in close contact with the metal body 1 and partially exposed from the opening of the groove, and a plurality of rectangular parallelepiped recesses 3 provided in a lattice pattern on the exposed surface of the foamed resin body 2 will be described. The difference from FIG. 1 is the number, size, and arrangement of the recesses 3. That is, in the foamed resin-metal composite 10 of FIG. 1, a plurality of rectangular parallelepiped recesses 3 are recessed in the foamed resin body 2 so that the recesses 3 are aligned in a row along the longitudinal direction of the long foamed resin body 2. On the other hand, in the foamed resin-metal composite 10 of FIG. 2, a plurality of rectangular parallelepiped recesses 3 are recessed in a lattice pattern on the exposed surface of the foamed resin body 2. In other words, as another example of the foamed resin-metal composite 10 of this embodiment, a plurality of rectangular parallelepiped recesses 3 are recessed into the elongated foamed resin body 2 so that each recess 3 is aligned in two rows along the longitudinal direction of the elongated foamed resin body 2. 2, similarly to Fig. 1, the rectangular columnar foamed resin body 2 is surrounded by the metal body 1 so that one of the four side surfaces of the rectangular columnar foamed resin body 2 is entirely exposed, and the rectangular columnar foamed resin body 2 and the metal body 1 are in close contact with each other. Therefore, by having a total of three surfaces, including the bottom and side surfaces, of the long metal body 1 provided with a groove having a rectangular cross section be closely surrounded by the foamed resin body 2, it is believed that deformation in the torsional direction of the metal can be suppressed and high bending strength can be exhibited. In addition, recesses 3 are recessed in a lattice pattern on the exposed surface where one entire side surface of the rectangular columnar foamed resin body 2 is exposed. The depth of the recesses 3 is a range that does not reach the metal body 1, that is, a range where the surface of the metal body 1 is not exposed. Therefore, the bottom of the recesses 3 is covered with the foamed resin body 2 (not shown). The long metal body 1 in FIG. 2 having a groove with a rectangular cross section is also open at both ends, as in FIG. 1, and there are exposed surfaces at both ends where the foamed resin body 2 is exposed. Also in FIG. 2, a pair of flanges 4a, 4b are provided along the longitudinal direction of the metal body 1. By providing these flanges, they can function as joints with other members.

[0021] The depth of the recess 3 in this embodiment can be appropriately set depending on the purpose of use as long as the metal body 1 is not exposed at the bottom of the recess 3. For example, assuming that the shortest distance from the exposed surface to the surface of the metal body 1 is 100%, the depth of the recess 3 is preferably 50% to 99%, and more preferably 60% to 95%, from the viewpoint of the balance between bending strength and lightweight.

[0022] The shape of the metal body 1 of this embodiment can be appropriately set depending on the purpose of use. For example, it can be a vessel shape, a gutter shape with one or both ends open, a cylinder shape, or a shape with a notch on the surface of any of these shapes. In Fig. 1 and Fig. 2, an elongated body with a rectangular cross section and a groove (or a gutter-shaped body with a rectangular cross section and both ends open) is given as an example of the shape of the metal body 1 of this embodiment, but the cross-sectional shape is not particularly limited, and examples thereof include shapes other than a rectangle, such as a V-shape, a C-shape, a U-shape, a square shape, or an arc shape.

[0023] The shape of the foamed resin body 2 of this embodiment can be appropriately set depending on the purpose of use, for example, a polygonal column shape, a semi-elliptical sphere shape or a hemisphere shape, an elliptical or (approximately) cylindrical shape, a cylindrical shape, a polygonal pyramid shape, an irregular shape, an elliptical or (approximately) conical shape, etc. can be mentioned.

[0024] 1 and 2 show the foamed resin-metal composite 10 in perspective, with multiple recesses 3 of the same size provided in the rectangular columnar foamed resin body 2. The size of the recesses 3, i.e., the opening area (maximum area of ​​the opening) of the recesses 3, can be set appropriately depending on the intended use. For example, from the viewpoint of a balance between bending strength and lightweight, the opening area (maximum area of ​​the opening) of the recesses 3 is preferably 10% to 90%, and more preferably 20% to 80%, of the entire exposed surface of the foamed resin body 2.

[0025] The shape of the recesses 3 can be appropriately set depending on the purpose of use. For example, the shape of the recesses 3 may be a polygonal prism, an ellipse or (approximately) columnar shape, a cylinder, a polygonal pyramid shape, an irregular shape, an ellipse or (approximately) cone shape, etc. In FIG. 1, the recesses 3 are arranged in a square prism shape, so they are also called "day"-shaped recesses 3.

[0026] The number of recesses 3 recessed on the exposed surface is appropriately set according to the shape of the foamed resin-metal composite 10. For example, when the foamed resin-metal composite 10 is an elongated body as shown in Figures 1 and 2, the number of recesses 3 recessed on the exposed surface is preferably within a range of 1 to 100 per meter, and more preferably within a range of 11 to 90 per meter. If recesses 3 are provided on the exposed surface where the foamed resin body 2 is exposed, there is an advantage that stress is dispersed when the metal deforms, and collision energy can be efficiently absorbed.

[0027] The "foamed resin body 2" and the metal body constituting the foamed resin-metal composite body of this embodiment will be described in detail below.

[0028] (Foam resin body 2) The foamed resin body 2 of the present embodiment may be either a closed-cell foam or an open-cell foam, and is preferably a closed-cell foam. <Closed bubble rate> In this embodiment, the closed cell ratio of the foamed resin body 2 is not particularly limited, but is preferably 30 to 99% or less. By having the closed cell ratio in this range, the elastic repulsive force is maintained during compression, the ability to conform to a mold or metal body is improved, and a design surface with high surface smoothness can be formed. In this embodiment, the closed cell ratio of the foamed resin body 2 is more preferably 80 to 99% or less, and even more preferably 85 to 99% or less, from the viewpoints of improving the strength of the foamed resin-metal composite body 10 and making it difficult for water to be taken up into the resin, which may occur in the open cell portion, and making it difficult for the density of the foamed resin body 2 to decrease. The closed cell ratio S (%) is calculated by the following formula (1). S(%)={(Vx-W / ρ) / (Va-W / ρ)}×100 (1) In the above formula (1), Vx is the true volume (cm 3 ) and Va is the apparent volume (cm ) of the foamed resin body 2. 3 ), W is the weight (g) of the foamed resin body 2, and ρ is the resin density (g / cm 3 ).

[0029] The expansion ratio of the expanded particles constituting the expanded resin body 2 of this embodiment is preferably 3.0 times or more, and more preferably 5.0 times or more, from the viewpoint of weight reduction. Also, from the viewpoint of maintaining the elastic repulsive force during compression, it is preferably less than 30 times, and more preferably 20 times or less. Here, the expansion ratio means the extent to which the volume has expanded from the state of the base resin through the inclusion (impregnation) of the foaming agent, the pre-foaming, and the final stage of foaming.

[0030] <Composition of foamed resin body 2> The foamed resin body 2 of the present invention preferably contains a thermoplastic resin in the form of foamed beads. Here, the term "expanded particles" in this specification refers to particles constituting the expanded resin body 2 of this embodiment, and refers to expanded particles obtained after the pre-expanded particles are subjected to the final stage of expansion. Also, the term "pre-expanded particles" in this specification refers to expandable particles that have not been subjected to the final stage of expansion, and includes the state before and after the preliminary expansion that is not the final stage is performed.

[0031] The thermoplastic resin is not particularly limited, but examples thereof include styrene-based polymers such as polyacetal, polystyrene, poly-α-methylstyrene, styrene-maleic anhydride copolymer, blends or graft polymers of polyphenylene oxide and polystyrene, acrylonitrile-styrene copolymers, acrylonitrile-butadiene-styrene polymers, styrene-butadiene copolymers, and high-impact polystyrene; vinyl chloride-based polymers such as polyvinyl chloride, vinyl chloride-vinyl acetate copolymers, post-chlorinated polyvinyl chloride, and copolymers of ethylene or propylene and vinyl chloride; polyvinylidene chloride-based copolymer resins; homo- and copolymer polyamide resins such as nylon-6 and nylon-6,6; and polybutylene. Examples of suitable resins include homo- and copolymer-based polyester resins such as terephthalate or polyethylene terephthalate; polyether resins such as polyethersulfone or polyetheretherketone; modified polyphenylene ether resins (phenylene ether-polystyrene alloy resins); polycarbonate resins; imide resins such as polyamideimide, polyimide, polyetherimide, and methacrylimide; polyphenylene sulfide resins; polysulfone resins; polyethersulfone resins; phenolic resins; urethane resins; polyolefin-based resins such as polypropylene or polymethylpentene; polyester-based resins; and fluorine-based resins such as polyvinylidene fluoride or polytetrafluoroethylene.

[0032] Examples of the polyolefin resin include polypropylene resins such as polypropylene polymerized using a Ziegler catalyst or a metallocene catalyst, ethylene-propylene random copolymer, propylene-butene random copolymer, ethylene-propylene block copolymer, and ethylene-propylene-butene terpolymer, and polyethylene resins such as low-density polyethylene, medium-density polyethylene, linear low-density polyethylene, linear very low-density polyethylene, high-density polyethylene, ethylene-vinyl acetate copolymer, ethylene-methyl methacrylate copolymer, and ionomer resin.

[0033] Particularly preferred thermoplastic resins include polyolefin resins, polyamide resins, polyester resins, polyether resins, methacrylic resins, modified polyether resins (phenylene ether-polystyrene alloy resins), and the like. Among these, polyamide resins are suitable as resins having excellent heat resistance, chemical resistance, and solvent resistance and suitable for use as highly heat-resistant foamed structural materials, and modified polyether resins (phenylene ether-polystyrene alloy resins) are suitable as resins having excellent heat resistance and high-temperature rigidity. The above thermoplastic resins may be used alone or in combination. The thermoplastic resin may be used in a non-crosslinked state or may be crosslinked by peroxide, radiation, or the like.

[0034] The foamed resin body 2 in this embodiment preferably contains 5 to 50 mass % of thermoplastic resin relative to the total amount (100 mass %) of the foamed resin-metal composite, and more preferably contains 10 to 40 mass %.

[0035] In this embodiment, the thermoplastic resin is preferably a polyamide resin. In other words, the foamed resin body 2 in this embodiment preferably contains a polyamide resin in the form of foamed particles, and the foamed resin body 2 more preferably contains a polyamide resin foam. This makes it easier to ensure the desired mechanical properties. Furthermore, by using a polyamide resin for the foamed resin body 2, heat resistance is ensured and the curing time can be shortened. Furthermore, by using a polyamide resin for the foamed resin body 2, the adhesive strength with the metal body 1 is further improved.

[0036] In the present embodiment, preferred polyamide resins that can be used include homopolymers alone, copolymers alone, mixtures of homopolymers, mixtures of copolymers, and mixtures of copolymers and homopolymers, which are obtained by appropriately combining polyamide-forming monomers such as ε-caprolactam, adipic acid, sebacic acid, dodecanedioic acid, isophthalic acid, terephthalic acid, hexamethylenediamine, tetramethylenediamine, 2-methylpentamethylenediamine, 2,2,4-trimethylhexamethylenediamine, 2,4,4-trimethylhexamethylenediamine, metaxylylenediamine, and bis(3-methyl-4-aminocyclohexyl)methane.

[0037] Specific examples of the polyamide resin include polycaproamide (nylon 6), polyhexamethylene adipamide (nylon 66), polytetramethylene adipamide (nylon 46), polytetramethylene sebacamide (nylon 410), polypentamethylene adipamide (nylon 56), polypentamethylene sebacamide (nylon 510), polyhexamethylene sebacamide (nylon 610), polyhexamethylene dodecamide (nylon 612), polydecamethylene adipamide (nylon 106), polydecamethylene sebacamide (nylon 1010), polydecamethylene dodecamide (nylon 1012), and polyundecane. amide (nylon 11), polydodecanamide (nylon 12), polycaproamide / polyhexamethylene adipamide copolymer (nylon 6 / 66), polycaproamide / polyhexamethylene terephthalamide copolymer (nylon 6 / 6T), polyhexamethylene adipamide / polyhexamethylene terephthalamide copolymer (nylon 66 / 6T), polyhexamethylene adipamide / polyhexamethylene isophthalamide copolymer (nylon 66 / 6I), polyhexamethylene adipamide / polyhexamethylene isophthalamide / polycaproamide copolymer (nylon 66 / 6I / 6), etc. are included. Note that the above " / " indicates a copolymer. In addition, in this embodiment, the polyamide resin may be used alone or in a mixture of two or more kinds. In addition, the foamed resin body 2 may be composed of only a polyamide resin foam.

[0038] In this embodiment, a bubble regulator may be added if it is necessary to adjust the average bubble diameter of the pre-expanded particles when forming the foamed resin body 2. Examples of the bubble regulator include talc, silica, calcium silicate, calcium carbonate, aluminum oxide, titanium oxide, diatomaceous earth, clay, sodium bicarbonate, alumina, barium sulfate, aluminum oxide, and bentonite, and the amount of the bubble regulator is usually 0.005 to 2 parts by mass with respect to 100 parts by mass of the total amount of the raw materials for the pre-expanded particles.

[0039] The pre-expanded particles can be obtained by impregnating a pelletized thermoplastic resin with a foaming agent to cause foaming. This foaming is not the final stage of foaming, but a pre-expanded stage. Examples of the blowing agent used in the production of the pre-expanded particles include volatile blowing agents, etc. Examples of the volatile blowing agent include linear or cyclic lower aliphatic hydrocarbons such as methane, ethane, propane, butane, isobutane, pentane, isopentane, neopentane, hexane, heptane, cyclopentane, cyclohexane, and methylcyclopentane, halogenated hydrocarbons such as dicyclodifluoromethane, trichloromonofluoromethane, 1-chloro-1,1-difluoroethane, and 1-chloro-2,2,2-trifluoroethane, and inorganic gas blowing agents such as nitrogen, air, and carbon dioxide.

[0040] The average particle size of the pre-expanded particles can be measured by a classification method using 100 g of the pre-expanded particles with a standard sieve as specified in JIS Z8801-1: 2006. The average particle size of the pre-expanded particles is preferably 1.0 to 4.0 mm, and more preferably 1.2 to 3.0 mm.

[0041] In this embodiment, the method for producing the pre-expanded particles can be (i) a method utilizing the thermoplasticity of the thermoplastic resin, or (ii) a method using post-processing such as cutting of the thermoplastic resin in a solid state, and any method that can give the particles a desired outer shape can be applied. Among them, a profile extrusion method using a die with an extrusion cross section can be preferably used as a method that is excellent in productivity and can produce particles with a stable shape. As the profile extrusion method, a method in which a thermoplastic resin is melt-extruded by an extruder, pelletized by a method commonly used in industry such as strand cutting or underwater cutting, and the obtained base resin pellets are expanded to obtain pre-expanded particles; a method in which a foaming agent is injected into an extruder from the middle of the barrel, foamed simultaneously with the discharge, and after cooling, underwater cutting or strand cutting is performed to directly obtain pre-expanded particles; a method in which a thermoplastic resin is melted in an extruder, extruded from a die having a desired cross-sectional shape, and cut to a predetermined length by a pelletizer after cooling to produce base resin pellets, and the base resin pellets are impregnated with a foaming agent and heated to expand at a predetermined expansion ratio; and the like can be produced by arbitrarily applying a conventionally known method.

[0042] The method of making the thermoplastic resin contain (impregnate) the foaming agent is not particularly limited, and may be a commonly used method.The method is not particularly limited, but may be, for example, a method using an aqueous medium such as water in a suspension system (suspension impregnation), a method using a thermal decomposition type foaming agent such as sodium bicarbonate (foaming agent decomposition), a method of making the gas in a liquid phase state by making it an atmosphere of the critical pressure or higher and contacting it with the base resin (liquid phase impregnation), a method of making the gas in a gas phase state by making it an atmosphere of the critical pressure or lower and contacting it with the base resin (gas phase impregnation), etc.

[0043] The foamed resin body 2 in this embodiment may further contain compounding ingredients, if necessary, in addition to the above-mentioned thermoplastic resin. Examples of the compounding agent include metal oxide compounds, antioxidants, light stabilizers, ultraviolet absorbers, flame retardants, cell regulators, foaming agents, colorants such as dyes or pigments, plasticizers, lubricants, crystallization nucleating agents, and inorganic fillers such as calcium carbonate. In the present embodiment, the compounding agents may be used alone or in combination of two or more.

[0044] "Metal body" The material of the metal body 1 in this embodiment is not particularly limited and can be appropriately selected depending on the application. For example, when weight reduction is important, the material of the metal body 1 is preferably, for example, an aluminum plate, an aluminum alloy plate, a magnesium plate, or a magnesium alloy plate. When mechanical strength is important, the material of the metal body 1 is preferably iron, steel, stainless steel, copper, copper alloy, manganese, manganese alloy, titanium, or a titanium alloy. When vibration damping is important, the material of the metal body 1 is preferably magnesium, a magnesium alloy, an iron-based alloy, a copper alloy, or a manganese alloy.

[0045] In this embodiment, the metal body 1 preferably has a hat shape. Furthermore, when the metal body 1 has a hat shape, the average thickness of the metal body 1 is not particularly limited, but is, for example, preferably 0.5 mm or more, more preferably 0.8 mm to 4 mm, and even more preferably 1 mm to 3 mm. If the average thickness of the metal body 1 is less than 0.5 mm, the mechanical strength will be insufficient and it will be difficult to produce a foamed resin-metal composite having the desired bending strength.

[0046] In this embodiment, the surface of the metal body 1, particularly the surface in contact with the foamed resin body 2, may be subjected to a surface treatment as necessary. Examples of the surface treatment include sandblasting, polishing, degreasing, etching, surface treatment by immersion or spraying with a rust inhibitor, chromium conversion treatment, phosphate conversion treatment, sulfide conversion treatment, anodizing, or fluororesin coating.

[0047] [Metal-resin composite materials] The present disclosure relates to a metal resin composite member having a foamed resin-metal composite of the present embodiment and a substrate. The foamed resin-metal composite has an exposed surface where the foamed resin is exposed, with the metal body partially surrounding and in close contact with the foamed resin. The substrate is attached to the foamed resin-metal composite so as to cover a part or the entire exposed surface. The method of attaching the substrate is not particularly limited and may be a known method, and it is preferable that the substrate and the metal body in the foamed resin-metal composite are joined or bonded to each other. As the bonding method, the substrate and the metal body in the foamed resin-metal composite may be bonded to each other using a known adhesive, or the metal body and the metallic substrate may be bonded to each other by soldering or heat fusion. A preferred aspect of this embodiment is, for example, when the metal body in the foamed resin-metal composite is an elongated groove-shaped body or hat-shaped body (hat-shaped body with a brim) with an edge, a joining means is provided in which a substrate and the groove-shaped metal body in the foamed resin-metal composite are overlapped with each other, the joining means comprising a first hole formed in the edge of the metal body, a second hole formed in the substrate, and a through shaft means that passes through these long holes to join the metal body and the substrate. The through shaft means may be configured to include, for example, a bolt as a shaft material (screw) that passes through first and second holes formed in the metal body and the base material, and a nut as a fastening member that fixes the bolt to the metal body and the base material to join the metal body and the base material. Alternatively, the through shaft means may be a shaft material such as a rivet that passes through first and second holes formed in the metal body and the base material to join the metal body and the base material. The material, shape and size of the substrate to which the foamed resin-metal composite of this embodiment is attached are not particularly limited, and various substrates (wood substrates, plastic substrates, metal substrates) can be mentioned. EXAMPLES

[0048] Hereinafter, the embodiments of the present invention will be described in more detail based on examples and comparative examples, but the present invention is not limited to these examples in any way.

[0049] 1. Evaluation method for foamed resin-metal composites [Evaluation of bending properties of foamed resin-metal composites] The impact bending test used in this embodiment and the comparative example was carried out using a large-scale, high-speed impact compression tester, IM10T-30, manufactured by IMATEK (UK), to measure the energy absorption amount according to the following specifications. [specification] Impact speed: 6.94m / s, weight of falling weight: 86kg, impact energy: 2000J, distance between supports: 500mm, jig shape: R60mm, falling weight shape R300mm The bending strength was measured by applying a load in the thickness direction. The area was calculated from the load-displacement curve, and the amount of absorbed energy was calculated. In addition, three types of test pieces (1) to (3) used for the evaluation of the impact bending test were prepared by changing the shape of the recesses according to the following procedure.

[0050] 2. Method for producing foamed resin-metal composite [Example 1] (Preparation of test piece (1)) <Preparation of foamed resin body> Polyamide 6 / 66 resin (2430A, manufactured by DSM Co., Ltd., surface tension at 20°C: 46 mN / m, indicated as "PA6 / 66" in the table) (containing 5.0% by mass of talc) was melted using an extruder, and the strand discharged from the extrusion die was pelletized underwater to obtain pellets with an average particle diameter of 1.4 mm. The melting point of this pellet was 193°C. The obtained pellets were placed in a pressure cooker at 10°C, and carbon dioxide gas of 4 MPa was blown in and absorbed for 12 hours. The carbon dioxide gas-impregnated pellets were then transferred to an expansion device, and air at 190°C was blown in for 20 seconds to obtain an aggregate of polyamide expanded particles. The obtained polyamide pre-expanded particles (1a) had an expansion ratio of 3.0 times, an average particle diameter of 2.0 mm, and an average diameter of closed cells of 0.12 mm.

[0051] The above polyamide pre-expanded particles (1a) were put into a water-permeable non-woven bag and immersed in a constant temperature water bath heated to 50°C for 30 minutes, and then water-containing polyamide pre-expanded particles (1b) were obtained. The water content of the polyamide pre-expanded particles (1b) was 12%. The obtained polyamide pre-expanded particles (1b) were sealed in an autoclave, and compressed air was introduced over 1 hour until the pressure inside the autoclave reached 0.8 MPa, and then the pressure was maintained at 0.8 MPa for 24 hours to subject the polyamide pre-expanded particles (1b) to a pressure treatment.

[0052] <Molding of the foamed resin body> As shown in Fig. 4(a), an in-mold foaming mold in the shape of a quadrangular prism with a (substantially) square cross-section (length in the longitudinal direction: 750 mm, upper base: 40 mm, lower base: 49 mm, height: 50 mm) was fabricated. Also, the concave portion formed in the quadrangular prism was processed into the core shape (protrusion) of the mold so as to be in the so-called "日" character shape shown in Figs. 1 and 4(a) and (b), in other words, a substantially rectangular parallelepiped (width 34 mm × height 20 mm × depth 41 mm). The pressure-treated polyamide pre-expanded particles (1c) were filled into the mold, and then the mold was clamped.

[0053] Thereafter, saturated steam at 105°C was supplied into the cavity for 10 seconds, and then saturated steam at 116°C was supplied into the cavity for 30 seconds to foam and thermally fuse the polyamide pre-expanded particles (1c), thereby molding the polyamide pre-expanded particles (1c) into a foamed resin body (1). By supplying cooling water into the cavity of the mold, the obtained foamed resin body (1) was cooled and then the mold was opened, and a quadrangular prism-shaped polyamide foamed resin body (1) in which the "日" character-shaped concave portions shown in Figs. 1 and 4(a) were periodically arranged was taken out. The specific volume of this polyamide foamed resin body (1) after drying was 3.5 (cc / g). FIG. 4(b) is a cross-sectional view of a polyamide foamed resin body (1) in which "sun"-shaped recesses are periodically arranged, produced using the in-mold foam molding die and the die provided with the approximately rectangular parallelepiped protrusions. More specifically, FIG. 4(b) is a cross-sectional view of the polyamide foamed resin body (1) cut along line BB in FIG. 4(a). As shown in FIG. 4(a), the recesses were periodically arranged in the longitudinal direction such that the interval between adjacent recesses was 7 mm. The number of recesses per meter was 36 / m.

[0054] <Preparation of adhesive composition> In order to bond the polyamide foam resin body (1) obtained above to a metal body described later (for example, Figs. 3(a) to (c)), an adhesive composition (instant adhesive primer and adhesive) was prepared. Specifically, the adhesive composition was used by applying an instant adhesive primer, TB1797E (ThreeBond 1797E (amine-based compound): manufactured by ThreeBond Co., Ltd.), to the surface of a polyamide foam resin body (1) and drying it, and then applying an adhesive, ThreeBond 1741 (manufactured by ThreeBond Co., Ltd.), to the dried coating film to adhere it to a metal body.

[0055] <Joining metal body and foamed resin body> A metal body (cold-rolled base sheet, Nippon Steel Corporation SECC-QS1X 270MPa steel) having the dimensions shown in Fig. 3 was prepared as the metal body 1 (also called a sill) covering the foamed resin body 2. Fig. 3(a) shows a perspective view of the metal body 1, Fig. 3(b) shows a front view of the metal body 1, and Fig. 3(c) shows a cross-sectional view of the metal body 1. Next, the instant adhesive primer was applied to the surface of the molded resin foam (1). The adhesive was then applied to the surface of the metal body to a desired thickness, and the adhesive was cured by treating the polyamide resin foam (1) at a specified temperature and time (23°C, 24 hours) in a composite molding die with a load of 30 kg applied to the polyamide resin foam (1). The adhesive composition that protruded from the edge was scraped off. A resin foam-metal composite (1) consisting of metal body-adhesive layer-polyamide resin foam (1) was then produced (see the image in FIG. 6(1)). Then, the foamed resin-metal composite (1) and a flat base material 5 (not shown) having a length in the longitudinal direction of the foamed resin-metal composite (1) were overlapped with the flat base material 5 so as to cover the exposed portion of the foamed resin of the foamed resin-metal composite (1). Then, as shown in Figures 4 and 5, a rivet 6 was driven so as to penetrate the end of the flat base material 5 (not shown) and the flange portions 4a, b of the metal body 1, and the foamed resin-metal composite (1) and the flat base material 5 (not shown) were joined by spot welding with the rivet 6 to produce a test piece (1). The flat plate-like base material 5 is, for example, the same as the metal base material 5 in FIG. 6(4). Therefore, the resin-metal composite member serving as the test piece (1) is composed of a foamed resin body 2, a metal body 1, and a substrate (not shown). The obtained test piece (1) was subjected to an impact bending test. The results are shown in Table 1. The total weight of the test piece (1) was 1670 g (foamed resin-metal composite (1) (1266 g) + substrate 5 (404 g)).

[0056] [Example 2] <Preparation of test piece (2)> <Forming of foamed resin> Similar to the above test piece (1), an in-mold foam molding mold was produced having a rectangular prism shape (longitudinal length: 750 mm, upper base: 40 mm, lower base: 49 mm, height: 50 mm) with a cross section that is (approximately) rectangular. In addition, the core shape (convex portion) of the mold of Example 2 was processed so that the concave portions formed in the quadrangular prism were in the so-called “T” shape shown in Figure 2, in other words, two rows of approximately rectangular prisms (15 mm wide × 20 mm high × 41 mm deep). The pressure-treated pre-expanded polyamide particles (1c) were filled into a metal mold, which was then clamped.

[0057] Then, saturated steam at 105°C was supplied into the cavity for 10 seconds, and saturated steam at 116°C was supplied into the cavity for 30 seconds to expand and heat-seal the polyamide pre-expanded particles (1c), thereby forming the polyamide pre-expanded particles (1c) into a foamed resin body (2). Cooling water was supplied into the cavity of the mold to cool the resulting foamed resin body (2), and the mold was then opened to take out a quadrangular prism-shaped polyamide foamed resin body (2) in which the square-shaped recesses shown in Figs. 2 and 6(2) were periodically arranged. The specific volume of this polyamide foamed resin body (2) after drying was 3.5 (cc / g). The number of recesses per 1 m length was 36 / m. Then, using the molded foamed resin body (2) in the same manner as in Example 1, a metal body (cold-rolled base plate, Nippon Steel Corporation SECC-QS1X 270 MPa steel) having the dimensions shown in FIG. 3 was bonded to the molded foamed resin body (2) to produce a foamed resin-metal composite (2) having a configuration of metal body-adhesive layer-molded foamed resin body (2) (see the image in FIG. 6(2)). Next, the foamed resin-metal composite (2) and a flat base material 5 (not shown) having a length in the longitudinal direction of the foamed resin-metal composite (2) were overlapped with the flat base material 5 so as to cover the exposed portion of the foamed resin of the foamed resin-metal composite (2). Then, as in the joints shown in Figures 4 and 5, rivets 6 were driven so as to penetrate the end of the flat base material 5 (not shown) and the flange portions 4a, b of the metal body 1, and the foamed resin-metal composite (2) and the flat base material 5 (not shown) were joined by spot welding with the rivets 6 to produce a test piece (2). The flat plate-like base material 5 (not shown) is the same as the metal base material 5 shown in FIG. 6(4), for example. That is, the test piece (2) is composed of the foamed resin body 2, the metal body 1, and a substrate (not shown). The obtained test piece (2) was subjected to an impact bending test. The results are shown in Table 1. The total weight of the test piece (2) was 1748 g (foamed resin-metal composite (1) (1344 g) + base material 5 (404 g)).

[0058] [Comparative Example 1] <Preparation of test piece (3)> A mold was prepared having a rectangular prism shape (longitudinal length: 750 mm, upper base: 40 mm, lower base: 49 mm, height: 50 mm) with a cross section similar to that of the above test piece (1). The pressurized polyamide pre-expanded particles (1c) were filled into the mold, and then the mold was clamped.

[0059] Thereafter, saturated steam at 105°C was supplied into the cavity for 10 seconds, and then saturated steam at 116°C was supplied into the cavity for 30 seconds to expand and heat-seal the polyamide pre-expanded particles (1c), thereby forming the polyamide pre-expanded particles (1c) into a foamed resin body (3). Cooling water was supplied into the cavity of the mold to cool the resulting foamed body (3), and then the mold was opened to remove the polyamide foamed resin body (3). The specific volume of this polyamide foamed resin body (3) after drying was 3.5 (cc / g). No recesses were formed in the polyamide foamed resin body (3). Then, using the molded foamed resin body (3) in the same manner as in Example 1, a metal body (cold-rolled base plate, Nippon Steel Corporation SECC-QS1X 270 MPa steel) having the dimensions shown in FIG. 3 was bonded to the molded foamed resin body (3) to produce a composite material laminate having a configuration of metal body-adhesive layer-molded foamed resin body (3) (see the image in FIG. 6(3)). Next, the foamed resin-metal composite (3) and a flat base material 5 (not shown) having a length in the longitudinal direction of the foamed resin-metal composite (3) were overlapped with the flat base material 5 so as to cover the exposed portion of the foamed resin of the foamed resin-metal composite (3). Then, as in the joints shown in Figures 4 and 5, rivets 6 were driven so as to penetrate the end of the flat base material 5 (not shown) and the flange portions 4a, b of the metal body 1, and the foamed resin-metal composite (3) and the flat base material 5 (not shown) were joined by spot welding with the rivets 6 to produce a test piece (3). The flat plate-like base material 5 (not shown) is the same as the metal base material 5 shown in FIG. 6(4), for example. That is, as shown in FIG. 6(3), the test piece (3) is composed of a foamed resin body 2 (without a recess), a metal body 1, and a substrate (not shown). Then, an impact bending test was performed on the obtained test piece (3). The results are shown in Table 1. The total weight of the test piece (3) was 1961 g (foamed resin-metal composite (3) (1557 g) + substrate 5 (404 g)).

[0060] <Preparation of control specimen> As a control, a metal body (cold-rolled base sheet, Nippon Steel Corporation SECC-QS1X 270 MPa steel material) having the dimensions shown in Fig. 3 was prepared (weight: 914 g) in the same manner as in the above-mentioned examples. The metal body and a flat base material (weight: 404 g) were joined with rivets to form a hollow closed space (see the image in Fig. 6(4)). That is, as shown in Fig. 6 (4), the control test piece does not have a foamed resin body 2, and is composed of a metal body 1 and a base material 5. After the base material 5 and the metal body 1 are overlapped, the metal body 1 and the base material 5 are joined by driving a rivet 6 into the base material 5 so that the end of the base material 5 penetrates through the flange portions 4a, b of the metal body 1, and spot welding using the rivet 6. The bending strength of the control test piece obtained above was measured under the same conditions.

[0061] 3. Evaluation results of test pieces (1) to (3) The bending strength results of the test pieces (1) to (3) and the control test piece prepared above are shown in Table 1 below.

[0062] [Table 1] From the above experimental results, it was confirmed that the foamed resin-metal composite and metal resin composite member of the present disclosure have a foamed resin body, and therefore the impact energy absorption is significantly improved compared to the control test piece. In addition, the test piece (3) without a recess is not preferable because there is a problem of remaining crushed due to the lack of unevenness. [Industrial Applicability]

[0063] The foamed resin-metal composite and metal resin composite member of the present embodiment can be provided as a structural member having excellent light weight and bending strength. Examples of applications of the foamed resin-metal composite and metal resin composite member of the present embodiment include components for vehicles such as automobiles, electric trains, and steam trains, aircraft, and buildings, which require light weight and bending strength. In particular, the composite members can be suitably used as interior materials, such as covers for covering parts. Taking advantage of the characteristics, the foamed resin-metal composite and metal resin composite member of the present invention can be suitably used for building materials and automobile parts, such as oil pans, engine covers, cylinder head covers, other cover-shaped parts, intake manifolds and their integrated parts, vehicle body structures, ducts, electrical equipment cases, battery cases, etc. [Explanation of symbols]

[0064] 1 metal body 2. Foam resin body 3. Recess 4a, 4b Flange part 5 Base material 6 Rivets 10. Foamed resin-metal composite

Claims

1. A foamed resin body and a metal body are included. The metal body partially surrounds and is in close contact with the foamed resin body, The foamed resin-metal composite has a recess in which the metal body does not reach the exposed surface of the foamed resin body.

2. A resin columnar body which is the foamed resin body; the metal body covering the columnar body so that a portion of a side surface of the columnar body is exposed and in close contact with the columnar body; The foamed resin-metal composite according to claim 1 , further comprising: a recess provided in the exposed surface.

3. 2. The foamed resin-metal composite according to claim 1, wherein the foamed resin contains a polyamide resin.

4. 2. The foamed resin-metal composite according to claim 1, wherein the number of the recesses formed on the exposed surface is within a range of 1 to 100 per meter.

5. The foamed resin-metal composite according to claim 1 , wherein the recesses are recessed into the exposed surface in a lattice pattern.

6. a resin rectangular columnar body which is the foamed resin body; the metal body covering the rectangular prism so that one of the four side surfaces of the rectangular prism is entirely exposed and in close contact with the rectangular prism; The foamed resin-metal composite according to claim 1 , further comprising: a recess provided in the exposed surface.

7. A metal resin composite member comprising: the foamed resin-metal composite according to any one of claims 1 to 6; and a substrate attached so as to cover an exposed surface of the foamed resin.

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