Metal material

Abstract

Provided is a metal material having excellent scratch resistance and excellent corrosion resistance. A metal material (1) according to the present disclosure comprises: a metal base material (10); a lower resin layer (20) formed on the metal base material (10); and an outermost resin layer (30) formed on the lower resin layer (20). The hardness HL the lower resin layer (20) is 0.18 GPa or greater. The hardness HH of the outermost resin layer (30) satisfies formula (1), and the thickness TL (μm) of the lower resin layer and the thickness TH (μm) of the outermost resin layer satisfy formula (2).　(1): HH / HL < 0.90 (2): TL + TH > 3.0

Description

metal material

[0001] The present disclosure relates to a metal material having a resin layer formed on its surface.

[0002] Design is often required for products such as building materials, automobiles, and electrical equipment (hereinafter also referred to as building materials, etc.). Recently, there has been a trend toward materials that utilize metallic textures, particularly in nature-oriented Europe and the United States. When utilizing metallic textures, metal sheets such as stainless steel sheets and aluminum sheets, which have excellent corrosion resistance, are used. In addition, metal sheets with textures, such as hairlines, formed on the surface are also available, with the aim of further enhancing the metallic feel of stainless steel sheets and aluminum sheets.

[0003] Furthermore, because stainless steel sheets and aluminum sheets are expensive, metal sheets with a plated layer on their surface have been developed as an alternative material to stainless steel sheets and aluminum sheets. Metal sheets with a plated layer have moderate corrosion resistance, similar to stainless steel sheets and aluminum sheets. Metal sheets with a plated layer also have an excellent metallic texture. Furthermore, by forming a texture on the surface of the plated layer, excellent design properties can be obtained. Therefore, metal sheets with a plated layer are suitable for applications such as building materials, similar to stainless steel sheets and aluminum sheets.

[0004] Metal materials for construction applications, such as metal plates, are formed into a predetermined shape by processing such as press working. Processing such as press working can result in burrs and chips on the edges of the metal material. If the burrs or chips collide with or come into contact with the surface of the metal material, scratches can occur on the surface of the metal material. Furthermore, when metal materials are used indoors, there is a possibility that furniture and other objects may collide with or come into contact with the surface of the metal material. Furthermore, when metal materials are used outdoors, there is a possibility that flying objects such as pebbles and metal fragments may collide with or come into contact with the surface of the metal material. In the following description, burrs, chips, furniture and other objects, pebbles, and metal fragments are collectively referred to as "flying objects, etc." As described above, scratches can occur on the surface of the metal material due to collisions or contact with these flying objects, etc. The occurrence of scratches reduces the corrosion resistance of the metal material. Therefore, metal materials for construction applications are required to have not only excellent corrosion resistance but also excellent scratch resistance.

[0005] Therefore, in order to obtain excellent corrosion resistance and also excellent scratch resistance in metal materials, a technique has been proposed in which a resin layer is formed on the surface of the metal material.

[0006] For example, Japanese Patent Laid-Open Publication No. 2006-124824 (Patent Document 1) discloses a metal material in which a hairline finish is applied to a zinc-plated steel sheet, and then a transparent resin coating is formed on the surface of the zinc plating layer on which the hairline has been formed. In the metal material disclosed in Patent Document 1, the transparent resin coating makes the surface of the plating layer visible, improving design, while also improving corrosion resistance and scratch resistance.

[0007] Furthermore, in the metal material disclosed in JP 2013-536901 A (Patent Document 2), a zinc-plated steel sheet is rolled to form a texture on the surface of the zinc-plated layer, and then the surface of the zinc-plated layer is coated with an organic film (resin) that provides a surface roughness within a certain range. The metal material disclosed in Patent Document 2 maintains corrosion resistance while making the surface of the plating layer visible, thereby enhancing designability.

[0008] JP 2006-124824 A JP 2013-536901 A

[0009] The metal materials described in Patent Documents 1 and 2 can have sufficient corrosion resistance while also having improved scratch resistance. However, excellent visibility, excellent corrosion resistance, and excellent scratch resistance may be obtained in the metal material by means other than those disclosed in Patent Documents 1 and 2.

[0010] An object of the present disclosure is to provide a metallic material having excellent corrosion resistance and excellent scratch resistance.

[0011] The metal material of the present disclosure includes a metal substrate, a lower resin layer, and an outermost resin layer. The lower resin layer is formed on the metal substrate. The outermost resin layer is formed on the lower resin layer as an outermost layer. The hardness HL of the lower resin layer is 0.18 GPa or more. The hardness HH of the outermost resin layer satisfies formula (1). The thickness TL (μm) of the lower resin layer and the thickness TH (μm) of the outermost resin layer satisfy formula (2). HH / HL<0.90 (1) TL+TH>3.0 (2)

[0012] The metal material of the present disclosure has excellent corrosion resistance and excellent scratch resistance.

[0013] Fig. 1 is a cross-sectional view perpendicular to the rolling direction of a metal material of this embodiment. Fig. 2 is a cross-sectional view perpendicular to the rolling direction of a metal material of this embodiment different from Fig. 1. Fig. 3 is a plan view of the surface of the metal substrate or the surface of the plating layer of Fig. 1 or Fig. 2. Fig. 4 is a cross-sectional view perpendicular to the rolling direction of another metal material of this embodiment different from Fig. 1.

[0014] The present inventors have conducted research into metal materials having excellent corrosion resistance and excellent scratch resistance.

[0015] The present inventors first attempted to improve excellent corrosion resistance and excellent scratch resistance by forming a resin layer on the surface of a metal material, similar to Patent Documents 1 and 2. As a result, it was found that sufficient corrosion resistance can be obtained by making the thickness of the resin layer greater than 3.0 μm.

[0016] However, it has been found that forming a resin layer on the surface of a metal material can provide sufficient corrosion resistance, but scratches may occur on the surface of the metal material. A scratched resin layer also reduces the corrosion resistance of the metal material. Therefore, the present inventors have investigated means for improving the scratch resistance of the resin layer.

[0017] The present inventors first considered hardening the resin layer. If the resin layer is hard, even if flying objects such as burrs, chips, furniture, pebbles, and metal pieces come into contact with the surface of the resin layer, it may be possible to prevent the tips of the flying objects from penetrating the resin layer. However, simply increasing the hardness of the resin layer still sometimes resulted in scratches on the resin layer and metal material. Therefore, the present inventors conducted further studies. As a result, the present inventors obtained the following findings.

[0018] In a metal material with an increased hardness resin layer, when the tip of a flying object or the like is pressed into the resin layer, the resin layer may exceed its limit of plastic deformation and be destroyed, or the resin layer may peel off from the metal material. These phenomena occur because, as a result of increasing the hardness of the resin layer, the resin layer is unable to adequately buffer the external force applied to the resin layer when the tip of the flying object or the like collides with or comes into contact with the resin layer.

[0019] Therefore, the present inventors have investigated means for buffering the external force applied to a resin layer by a flying object or the like when the flying object or the like collides with or comes into contact with the resin layer. By reducing the hardness of the resin layer, the plastic deformation tolerance of the resin layer can be increased. Therefore, when the tip of a flying object or the like is pressed into the resin layer, it may be possible to prevent the resin layer from exceeding its plastic deformation limit and being destroyed, or the resin layer from peeling off from the metal material.

[0020] Based on the above-mentioned results, the inventors evaluated the scratch resistance by lowering the hardness of the resin layer formed on the surface of the metal material. As a result, when the hardness of the resin layer was simply lowered, the damage or peeling of the resin layer due to a flying object or the like that collided with or came into contact with the resin layer was suppressed, but there were cases where the tip of the flying object that collided with or came into contact with the resin layer penetrated the resin layer, causing scratches on the surface of the metal material.

[0021] Therefore, the present inventors considered that sufficient scratch resistance cannot be obtained when the resin layer is a single layer, and therefore considered forming the resin layer into a plurality of layers each having a different role, rather than forming the resin layer into a single layer.

[0022] The inventors first considered constructing a resin layer comprising a lower resin layer formed on a metal substrate and an outermost resin layer formed on the lower resin layer to serve as the outermost layer. They then considered that scratch resistance could be improved by making the outermost resin layer, which is subject to collision or contact with flying objects, harder and making the lower resin layer softer than the outermost resin layer. In this configuration, the lower resin layer serves to buffer the outermost resin layer from impact or contact with flying objects. Meanwhile, the outermost resin layer serves to protect the outermost resin layer from impact or contact with flying objects.

[0023] However, it has been found that the above-described configuration does not provide sufficient scratch resistance, resulting in a decrease in the corrosion resistance of the metal material. The following factors are considered to be the reasons for this. If the outermost resin layer is hard and the lower resin layer is softer than the outermost resin layer, the outermost resin layer will be destroyed by the flying object if it cannot withstand the impact or contact of the flying object. In this case, the lower resin layer, which is softer than the outermost resin layer, cannot provide protection against the flying object. As a result, the flying object penetrates the lower resin layer and reaches the surface of the metal material, causing scratches.

[0024] Based on the above findings, the inventors considered intentionally making the outermost resin layer, which collides with or comes into contact with flying objects, softer than the lower resin layer. In this case, the outermost resin layer acts to buffer the external force caused by the collision or contact of flying objects. Meanwhile, the lower resin layer, which is harder than the outermost resin layer, acts to repel and protect the flying objects, which have been buffered by the force. The inventors considered that this combination would improve the scratch resistance and corrosion resistance of metal materials.

[0025] Therefore, the present inventors further investigated the relationship between the hardness HL (GPa) of the lower resin layer and the hardness HH (GPa) of the outermost resin layer and the scratch resistance and corrosion resistance. As a result, the present inventors found that if the hardness HL of the lower resin layer is 0.18 GPa or more, the hardness HH of the outermost resin layer satisfies formula (1), and the thickness TL (μm) of the lower resin layer and the thickness TH (μm) of the outermost resin layer satisfy formula (2), excellent scratch resistance and corrosion resistance can be obtained in a metal material. HH / HL<0.90 (1) TL+TH>3.0 (2)

[0026] The metal material of the present disclosure has been completed based on the above-mentioned technical idea and has the following configuration.

[0027] The metal material of the first configuration includes a metal substrate, a lower resin layer, and an outermost resin layer. The lower resin layer is formed on the metal substrate. The outermost resin layer is formed as an outermost layer on the lower resin layer. The hardness HL of the lower resin layer is 0.18 GPa or more. The hardness HH of the outermost resin layer satisfies formula (1). The thickness TL (μm) of the lower resin layer and the thickness TH (μm) of the outermost resin layer satisfy formula (2). HH / HL<0.90 (1) TL+TH>3.0 (2)

[0028] In the metal material of the first configuration, an outermost resin layer having a lower hardness than the lower resin layer is formed on the lower resin layer. Therefore, when a flying object or the like collides with or comes into contact with the metal material, the outermost resin layer, which has a lower hardness than the lower resin layer, buffers the external force generated by the collision or contact. Furthermore, the lower resin layer, which has a higher hardness than the outermost resin layer, deflects the tip of the flying object or the like, buffering the force. By setting the hardness HL of the lower resin layer to 0.18 GPa or more and the hardness HH of the outermost resin layer satisfying formula (1), the lower-hardness outermost resin layer and the higher-hardness lower resin layer prevent the tip of the flying object or the like from penetrating the lower resin layer and causing scratches on the metal material. As a result, the metal material achieves excellent scratch resistance. Furthermore, by setting the thickness TL (μm) of the lower resin layer and the thickness TH (μm) of the outermost resin layer to satisfy formula (2), excellent corrosion resistance is achieved.

[0029] The metal material of the second component is the metal material of the first component, and the hardness HH of the outermost resin layer is 0.13 GPa or more.

[0030] The metal material of the second configuration has even higher scratch resistance.

[0031] The third metal material is the first metal material, and the thickness TL of the lower resin layer is 0.5 μm or more.

[0032] The metal material of the third configuration has even higher scratch resistance.

[0033] The fourth metal material is the first metal material, and the thickness TH of the outermost resin layer is 2.0 μm or more.

[0034] The metal material of the fourth configuration has further improved corrosion resistance and scratch resistance.

[0035] The metal material of the fifth configuration is the metal material of the first configuration, and the thickness TL and the thickness TH satisfy the formula (3): TL + TH ≦ 20.0 (3)

[0036] The metal material of the fifth configuration further enhances the design.

[0037] The metal material of the sixth configuration is the metal material of the first configuration, and the thickness TL and the thickness TH satisfy the formula (4): TH / TL≧1.3 (4)

[0038] The metal material of the sixth configuration has even higher scratch resistance.

[0039] The metal material of the seventh configuration is the metal material of the first configuration, further comprising a plating layer formed on the metal base material, and a lower resin layer formed on the plating layer.

[0040] The metal material of the seventh configuration provides even better corrosion resistance.

[0041] The metal material of an eighth aspect is the metal material of the seventh aspect, wherein the metal substrate is a steel material, and the plating layer is made of one or more types selected from the group consisting of Zn plating, Zn—Ni alloy plating, Zn—Fe plating, Zn—Co plating, Zn—Al plating, Zn—Fe—Al plating, Al—Si plating, and Zn—Al—Mg plating.

[0042] In the metal material of the eighth configuration, a plating layer having a sacrificial anticorrosion function is formed, which further improves corrosion resistance.

[0043] The metal material of the ninth configuration is the metal material of the first configuration, and the lower resin layer contains an organic resin and an inorganic pigment. The organic resin is one or more selected from the group consisting of polyester, urethane, and melamine. The inorganic pigment is BaSO. ４ , SiO ２ , ZrO, TiO ２ and ZnO.

[0044] In the metal material of the ninth configuration, the hardness HL of the lower resin layer can be adjusted to 0.18 GPa or more by using an inorganic pigment.

[0045] The metal material of the tenth configuration is the metal material of the first configuration, wherein the outermost resin layer contains an organic resin made of one or more kinds selected from the group consisting of polyester and melamine.

[0046] The metal material of the eleventh configuration is the metal material of the first configuration, and has a texture formed on the surface of the metal material.

[0047] The metal material of the eleventh configuration further enhances the design.

[0048] The metal material of the twelfth configuration is the metal material of the seventh configuration, in which a texture is formed on the surface of the plating layer.

[0049] The metal material of the twelfth configuration further enhances the design.

[0050] The metal material of the thirteenth configuration is the metal material of the eleventh or twelfth configuration, and has a hairline texture.

[0051] The metal material of the thirteenth configuration further enhances the design.

[0052] The metal material of a fourteenth aspect is the metal material of the first aspect, further comprising a chemical conversion coating. The chemical conversion coating is formed on the metal substrate. The underlayer resin is formed on the chemical conversion coating.

[0053] The metal material of the fourteenth configuration has even higher corrosion resistance.

[0054] The metal material of this embodiment will be described in detail below.

[0055] <1. Regarding the metal material 1> Fig. 1 is a cross-sectional view perpendicular to the rolling direction of the metal material 1 of this embodiment. In Fig. 1, the rolling direction of the metal material 1 is defined as the L direction. The thickness direction of the metal material 1 is defined as the T direction. The direction perpendicular to the L direction and T direction of the metal material 1 (i.e., the width direction of the metal material 1) is defined as the W direction.

[0056] Referring to FIG. 1 , the metal material 1 of this embodiment includes a metal substrate 10, a plating layer 11, a lower resin layer 20, and an outermost resin layer 30. The metal substrate 10 is a member that serves as the base material of the metal material 1. The lower resin layer 20 and the outermost resin layer 30 improve the corrosion resistance and scratch resistance of the metal material 1. As shown in FIG. 2 , the metal material 1 of this embodiment includes the metal substrate 10, the lower resin layer 20, and the outermost resin layer 30, and does not necessarily include the plating layer 11. In other words, in the metal material 1 of this embodiment, the plating layer 11 has an optional configuration. The metal substrate 10, the plating layer 11, the lower resin layer 20, and the outermost resin layer 30 will be described below.

[0057] <2. Regarding the metal substrate 10> The metal substrate 10 is a member that serves as a base material for the metal material 1. For the metal substrate 10, a metal that suits the mechanical properties (e.g., tensile strength, workability, etc.) required for the metal material 1 may be used. In other words, the type of metal substrate 10 is not particularly limited. The metal substrate 10 is, for example, a steel material, an aluminum material, an aluminum alloy material, a titanium alloy material, etc. The shape of the metal substrate 10 is not particularly limited. The shape of the metal substrate 10 may be, for example, a plate shape, a rod shape, or a tube shape.

[0058] When the metal substrate 10 is a steel plate, the type of the steel plate is, for example, SPHC, SPHD, SPHE, SPCC, SPCD, SPCF, etc., as specified in the JIS standard (JIS G 3131:2018). When the metal substrate 10 is an aluminum plate, the type of the aluminum plate is, for example, A1050P, A1080P, A1070P, A1100P, etc., as specified in the JIS standard (JIS H 4000:2014). When the metal substrate 10 is an aluminum alloy plate, the type of the aluminum alloy plate is, for example, A2014P, A3003P, A3104P, A5005P, etc., as specified in the JIS standard (JIS H 4000:2014).

[0059] <3. Regarding the plating layer 11> As described above, the plating layer 11 is an optional configuration in the metal material 1 of the present embodiment. That is, the metal material 1 may or may not include the plating layer 11. When the metal material 1 includes the plating layer 11, the corrosion resistance of the metal material 1 is further improved.

[0060] The plating layer 11 may be, for example, a Ni-based plating layer, a Cu-based plating layer, a zinc-based plating layer (Zn-based plating layer), an Au-based plating layer, a Sn-based plating layer, an Al-based plating layer, or an alloy plating layer containing one or more of Ni, Cu, Zn, Au, Sn, and Al. The above-mentioned X-based plating layer (X is one of Ni, Cu, Zn, Au, Sn, and Al) refers to a plating layer consisting mainly of X. "Consisting mainly of X" means that the content of X, which is the main component element in the plating layer, is at least 50% by mass. For example, a zinc-based plating layer refers to a plating layer with a Zn content of 50% by mass or more.

[0061] When the metal substrate 10 is a steel material, the plating layer 11 is preferably made of one or more types selected from the group consisting of a zinc-based plating layer and an Al-based plating layer. Zn and Al are less noble metals than Fe. Therefore, the zinc-based plating layer and the Al-based plating layer exert a sacrificial corrosion protection function on the metal substrate 10, which is a steel material. As a result, excellent corrosion resistance is obtained.

[0062] The zinc-based plating layer may be a plating layer made of zinc plating or a plating layer made of zinc alloy plating.

[0063] The zinc-based plating layer is formed by a known plating process. For example, the zinc-based plating layer may be formed by either an electroplating method or a hot-dip plating method. The zinc-based plating layer is a concept that includes an electrogalvanized layer, an electrozinc alloy plated layer, a hot-dip galvanized layer, and an alloyed hot-dip galvanized layer.

[0064] The zinc-based plating layer may have any known chemical composition. The preferred Zn content in the chemical composition of the zinc-based plating layer is 65% by mass or more. If the Zn content is 65% by mass or more, the sacrificial corrosion protection function is significantly exhibited, and the corrosion resistance of the metal material 1 is significantly improved. The preferred lower limit of the Zn content in the chemical composition of the zinc-based plating layer is 70% by mass, and more preferably 80% by mass.

[0065] The chemical composition of the zinc-based plating layer preferably contains Zn and one or more elements selected from the group consisting of Al, Fe, Co, Cr, Cu, Ni, P, Si, Sn, Mg, Mn, Mo, V, W, Zr, Ca, Y, La, Ce, Bi, In, Ti, V, Nb, Cu, Mn, Sr, Sb, Pb, and B. Furthermore, when the zinc-based plating layer is an electrogalvanized layer, the chemical composition of the zinc-based plating layer more preferably contains 5 to 20 mass% in total of one or more elements selected from the group consisting of Fe, Ni, and Co. When the zinc-based plating layer is a hot-dip galvanized layer, the chemical composition of the zinc-based plating layer more preferably contains 5 to 49 mass% in total of one or more elements selected from the group consisting of Mg, Al, and Si. In these cases, the zinc-based plating layer exhibits even better corrosion resistance.

[0066] Preferably, the zinc-based plating layer is made of Zn—Ni alloy plating, which has excellent corrosion resistance and high hardness, making it suitable as the zinc-based plating layer.

[0067] When the entire chemical composition of the Zn—Ni alloy plating is taken as 100% by mass, the preferred Ni content is 10 to 20% by mass. In this case, the Zn—Ni alloy plating is a single γ phase. Therefore, the hardness of the Zn—Ni alloy plating is further increased. A more preferred lower limit of the Ni content is 11% by mass, even more preferably 12% by mass, and even more preferably 14% by mass. A more preferred upper limit of the Ni content is 18% by mass, even more preferably 17% by mass, and even more preferably 16% by mass.

[0068] The zinc-based plating layer may contain impurities. Here, the term "impurities" refers to elements that are mixed in the raw materials or that are unintentionally mixed in during the manufacturing process. Examples of impurities include Ti, B, S, N, C, Nb, Pb, Cd, Ca, Pb, Y, La, Ce, Sr, Sb, O, F, Cl, Ag, and H. In the chemical composition of the plating layer 11, the total content of impurities is preferably 1% or less.

[0069] More preferably, the plating layer is made of one or more selected from the group consisting of Zn plating, Zn—Ni alloy plating, Zn—Fe plating, Zn—Co plating, Zn—Al plating, Zn—Fe—Al plating, Al—Si plating, and Zn—Al—Mg plating.

[0070] The Zn—Ni plating has a chemical composition with a Zn content of 50% by mass or more and a Ni content of 9% by mass or more. The Zn—Fe plating has a chemical composition with a Zn content of 50% by mass or more and a Fe content of 10% by mass or more. The Zn—Co plating has a chemical composition with a Zn content of 50% by mass or more and a Co content of 0.1% by mass or more. The Zn—Al plating has a chemical composition with a Zn content of 50% by mass or more and an Al content of 0.1% by mass or more. The Zn—Fe—Al plating has a chemical composition with a Zn content of 50% by mass or more, a Fe content of 8.0% by mass or more, and an Al content of 0.1% by mass or more. The Zn—Al—Mg plating has a chemical composition with a Zn content of 50% by mass or more, an Al content of 1.0% by mass or more, and a Mg content of 0.5% by mass or more. The Al-Si plating has a chemical composition in which the Al content is 50% by mass or more and the Si content is 2% by mass or more.

[0071] [3.1. Method for Measuring the Chemical Composition of the Plating Layer 11] The chemical composition of the plating layer 11 is measured, for example, by the following method. A test piece including the plating layer 11 and the surface of the plating layer 11 is prepared from the metal material 1. The cross section of the test piece perpendicular to the surface of the plating layer 11 is used as the observation surface. After embedding the test piece in resin, the observation surface of the test piece is mirror-polished. After polishing, 10 fields of view are selected arbitrarily in the plating layer 11 within the observation surface. Each field of view is 0.5 μm × 0.5 μm. Each field of view is subjected to area analysis by energy dispersive X-ray spectrometry (EDS). The content of elements contained in each measurement field of view is determined by the EDS area analysis. In EDS area analysis, the acceleration voltage is set to 15 kV, and the target elements are quantified as Zn, Al, Co, Cr, Cu, Fe, Ni, P, Si, Sn, Mg, Mn, Mo, V, W, and ZrTi, B, S, N, C, Nb, Pb, Cd, Ca, Pb, Y, La, Ce, Sr, Sb, O, F, Cl, Ag, and H.

[0072] The arithmetic mean value of the content of each element obtained at the 10 locations is calculated. If the obtained Zn content (arithmetic mean value) is 50 mass% or more, the plating layer 11 to be measured is determined to be a zinc-based plating layer.

[0073] 3, a texture TX may be formed on the surface 10S of the metal substrate 10 or the surface 11S of the plating layer 11 (hereinafter, the surface 10S of the metal substrate 10 and the surface 11S of the plating layer 11 will be collectively referred to as the "metal surface S"). Here, the texture TX refers to an uneven pattern formed on the metal surface S by a physical or chemical method. The texture TX is a three-dimensional uneven pattern on the metal surface S. The texture TX further enhances the design of the metal material 1.

[0074] The texture TX is, for example, a well-known hairline, embossment, dot, vibration, blast, hammered, satin, etc. Preferably, the texture TX is a hairline.

[0075] The texture TX may be formed on a part of the metal surface S, or may be formed on the entire metal surface S. In other words, there may be a part of the metal surface S where the texture TX is not formed.

[0076] <4. Regarding the lower resin layer 20 and the outermost resin layer 30> The lower resin layer 20 and the outermost resin layer 30 improve the corrosion resistance and scratch resistance of the metal material 1. Specifically, the hardness HL of the lower resin layer 20 is 0.18 GPa or more. Furthermore, the hardness HH of the outermost resin layer 30 satisfies formula (1), and the thickness TL (μm) of the lower resin layer 20 and the thickness TH (μm) of the outermost resin layer 30 satisfy formula (2). HH / HL<0.90 (1) TL+TH>3.0 (2) These matters will be explained below.

[0077] 4.1. Hardness HL of Lower Resin Layer 20 The lower resin layer 20 has a protective effect of repelling the tip of a flying object or the like whose external force has been buffered by the outermost resin layer 30 .

[0078] If the hardness HL of the lower resin layer 20 is less than 0.18 GPa, sufficient protective effect cannot be obtained. Therefore, when a flying object or the like collides with or comes into contact with the surface of the outermost resin layer 30 of the metal material 1, the tip of the flying object or the like may reach the metal surface S and cause a scratch. In this case, the scratch resistance of the metal material 1 is reduced. Therefore, the hardness HL of the lower resin layer 20 is set to 0.18 GPa or more.

[0079] The lower limit of the hardness HL of the lower resin layer 20 is preferably 0.19 GPa, more preferably 0.20 GPa, even more preferably 0.21 GPa, even more preferably 0.22 GPa, and even more preferably 0.23 GPa. There is no particular limitation on the upper limit of the hardness HL of the lower resin layer 20. When the processability of the lower resin layer 20 is to be further improved, the upper limit of the hardness HL is preferably 0.38 GPa, more preferably 0.36 GPa, even more preferably 0.35 GPa, even more preferably 0.33 GPa, and even more preferably 0.30 GPa.

[0080] [4.2. Regarding Formula (1)] Furthermore, the hardness HL of the lower resin layer 20 and the hardness HH of the outermost resin layer 30 satisfy the formula (1): HH / HL<0.90 (1)

[0081] When the hardness HL of the lower resin layer 20 and the hardness HH of the outermost resin layer 30 satisfy formula (1), the outermost resin layer 30, which has a lower hardness than the lower resin layer 20, adequately buffers the external force generated by the collision or contact of a flying object or the like. Furthermore, the lower resin layer 20, which has a higher hardness than the outermost resin layer 30, deflects the tip of the flying object or the like, buffering the force. In this way, the combination of the lower resin layer 20 and the outermost resin layer 30 that satisfies formula (1) fully functions as the protective function of the lower resin layer 20 and the buffering function of the outermost resin layer 30. Therefore, the tip of the flying object or the like is prevented from penetrating the lower resin layer 20 and forming scratches on the metal surface S. As a result, the metal material 1 achieves excellent scratch resistance.

[0082] The upper limit of HH / HL is preferably 0.89, more preferably 0.88, even more preferably 0.86, even more preferably 0.84, even more preferably 0.82, and even more preferably 0.80. The lower limit of HH / HL is preferably 0.38, more preferably 0.40, even more preferably 0.45, even more preferably 0.50, even more preferably 0.55, even more preferably 0.60, even more preferably 0.65, and even more preferably 0.70.

[0083] 4.3. Preferable Lower Limit of Hardness HH of Outermost Resin Layer 30 Preferably, the hardness HH of the outermost resin layer 30 is 0.13 GPa or more. In this case, the scratch resistance of the metal material 1 is further improved.

[0084] A more preferable lower limit of the hardness HH of the outermost resin layer 30 is 0.15 GPa, even more preferably 0.16 GPa, even more preferably 0.18 GPa, and even more preferably 0.20 GPa. There is no particular limitation on the upper limit of the hardness HH of the outermost resin layer 30. When the processability of the outermost resin layer 30 is to be further improved, a preferable upper limit of the hardness HH is 0.30 GPa, even more preferably 0.28 GPa, even more preferably 0.26 GPa, even more preferably 0.25 GPa, and even more preferably 0.24 GPa.

[0085] [4.4. Regarding Formula (2)] The thickness TL (μm) of the lower resin layer 20 and the thickness TH (μm) of the outermost resin layer 30 satisfy the formula (2): TL+TH>3.0 (2)

[0086] TL+TH means the total thickness of the resin layers (the lower resin layer 20 and the outermost resin layer 30). TL+TH is related to the corrosion resistance of the metal material 1. If TL+TH satisfies formula (2), the resin layers (the lower resin layer 20 and the outermost resin layer 30) are sufficiently thick. Therefore, the metal material 1 can obtain excellent corrosion resistance.

[0087] The lower limit of TL+TH is preferably 3.2 μm, more preferably 3.5 μm, even more preferably 3.8 μm, even more preferably 4.0 μm, even more preferably 4.3 μm, and even more preferably 4.5 μm.

[0088] [4.5. Regarding Formula (3)] Preferably, the total thickness TL+TH of the resin layers (the lower resin layer 20 and the outermost resin layer 30) satisfies formula (3): TL+TH≦20.0 (3)

[0089] If TL+TH is 20.0 μm or less, when a texture TX, typically a hairline, is formed on the metal surface S (surface 10S of metal substrate 10 or surface 11S of plating layer 11), when the metal material 1 is visually observed, the design quality of the texture TX is sufficiently high even through the lower resin layer 20 and the outermost resin layer 30.

[0090] Both the lower resin layer 20 and the outermost resin layer 30 are translucent. Here, "translucent" means that the metal surface S is visible when the metal material 1 is placed in an environment equivalent to sunlight on a clear morning (illuminance of approximately 65,000 lux).

[0091] A more preferable upper limit of TL+TH is 19.8 μm, even more preferably 19.0 μm, even more preferably 18.0 μm, even more preferably 17.0 μm, even more preferably 16.0 μm, even more preferably 15.0 μm, even more preferably 14.0 μm, even more preferably 13.0 μm, and even more preferably 12.0 μm.

[0092] [4.6. Regarding Formula (4)] Preferably, the thickness TL of the lower resin layer 20 and the thickness TH of the outermost resin layer 30 satisfy the formula (4): TH / TL≧1.3 (4)

[0093] TH / TL is related to scratch resistance. When TH / TL is 1.3 or more, the outermost resin layer 30 is sufficiently thicker than the lower resin layer 20. In this case, the buffering effect of the outermost resin layer 30 is fully exerted. As a result, the scratch resistance of the resin layers (the lower resin layer 20 and the outermost resin layer 30) is further improved. A more preferable lower limit of TH / TL is 1.4, more preferably 1.5, even more preferably 1.6, even more preferably 1.7, even more preferably 1.8, and even more preferably 1.9. A more preferable upper limit of TH / TL is 16.0, even more preferably 12.0, even more preferably 10.0, even more preferably 9.0, even more preferably 7.0, and even more preferably 6.0.

[0094] [4.7. Preferable Thickness TL of Lower Resin Layer 20] Preferably, the thickness TL (μm) of the lower resin layer 20 is 0.5 μm or more. If the thickness TL of the lower resin layer 20 is 0.5 μm or more, the lower resin layer 20 exerts a stronger protective effect. Therefore, scratch resistance is further improved. Therefore, the preferable thickness TL is 0.5 μm or more.

[0095] The lower limit of the thickness TL is more preferably 0.8 μm, more preferably 1.0 μm, even more preferably 1.2 μm, even more preferably 1.4 μm, and even more preferably 1.6 μm. The upper limit of the thickness TL is more preferably 8.5 μm, even more preferably 8.0 μm, even more preferably 7.5 μm, even more preferably 7.0 μm, even more preferably 6.5 μm, even more preferably 6.0 μm, even more preferably 5.5 μm, and even more preferably 5.0 μm.

[0096] [4.8. Preferable Thickness TH of Outermost Resin Layer 30] Preferably, the thickness TH (μm) of the outermost resin layer 30 is 2.0 μm or more. If the thickness TH of the outermost resin layer 30 is 2.0 μm or more, the outermost resin layer 30 exerts a stronger buffering effect. This further improves scratch resistance. Therefore, the preferable thickness TH is 2.0 μm or more.

[0097] The lower limit of the thickness TH is more preferably 2.2 μm, even more preferably 2.5 μm, even more preferably 3.0 μm, even more preferably 3.5 μm, and even more preferably 4.0 μm. The upper limit of the thickness TH is more preferably 15.0 μm, even more preferably 14.5 μm, even more preferably 14.0 μm, even more preferably 13.5 μm, even more preferably 13.0 μm, even more preferably 12.5 μm, even more preferably 12.0 μm, even more preferably 10.0 μm, even more preferably 9.0 μm, and even more preferably 8.5 μm.

[0098] [4.9. Method for measuring hardness HL and thickness TL of lower resin layer 20, and hardness HH and thickness TH of outermost resin layer 30] The hardness HL (GPa) and thickness TL (μm) of the lower resin layer 20, and the hardness HH (GPa) and thickness TH (μm) of the outermost resin layer 30 are measured as follows.

[0099] A test piece is taken that includes a cross section parallel to the normal direction of the surface of the metal material 1, the surface of the metal material 1, and the lower resin layer 20 and the outermost resin layer 30. Of the surfaces of the test piece, the cross section parallel to the normal direction of the surface of the metal material 1 is defined as the observation surface.

[0100] The observation surface of the test piece is cut using a microtome in a direction perpendicular to the depth direction of the metal material 1 until the effects of sagging due to shear cutting are eliminated, exposing a smooth observation surface. On the observation surface of the test piece after cutting with the microtome, hardness (GPa) is measured by nanoindentation at each measurement point at a 0.2 μm pitch in the depth direction of the metal material 1, from the surface of the metal material 1 (i.e., the surface of the outermost resin layer 30) to the interface between the lower resin layer 20 and the metal surface S. The positions of each measurement point are shifted in the width direction perpendicular to the depth direction of the metal material 1 on the observation surface so that the indentations described below at adjacent measurement points do not overlap each other.

[0101] At each measurement point, hardness is measured using a nanoindenter. Specifically, using a Berkovich indenter, hardness at each measurement point is measured by nanoindentation in accordance with the method described in ISO 14577. The load during measurement is 200 μN, the loading time is 5 seconds, the holding time is 2 seconds, and the unloading time is 5 seconds. The nanoindenter is, for example, a Hysitron TI 980 manufactured by Bruker.

[0102] The above-mentioned hardness measurements are performed at 10 locations arranged at a 100 μm pitch on an arbitrary line segment on the surface of the metal material 1. Of the hardness values ​​obtained at 10 measurement points at the same depth position from the surface of the outermost resin layer 30, the hardness value at the measurement point where the indentation is clearly visible is selected. If the indentation shape is the same as the projected shape of the indenter and the outer edge of the indentation shape is not missing, the indentation is determined to be clear. Of the selected hardness values, four hardness values ​​are selected in descending order of value, starting with the highest hardness value. The arithmetic mean of the four selected hardness values ​​is calculated. The obtained value is defined as the hardness (GPa) at that depth position. The hardness value obtained by arithmetic mean is the value obtained by rounding off to two decimal places.

[0103] The relationship between the hardness at each depth position and the depth position is graphed. In the graph obtained, the depth position where the hardness changes discontinuously is identified as the interface between the lower resin layer 20 and the outermost resin layer 30.

[0104] Based on the identified interface, the arithmetic mean value of the hardnesses at all measurement points within the range of the lower resin layer 20 is defined as the hardness HL (GPa) of the lower resin layer 20. Based on the identified interface, the arithmetic mean value of the hardnesses at all measurement points within the range of the outermost resin layer 30 is defined as the hardness HH (GPa) of the outermost resin layer 30. Furthermore, based on the identified interface, the thickness TL (μm) of the lower resin layer 20 and the thickness TH (μm) of the outermost resin layer 30 are determined. Specifically, the arithmetic mean value of the thicknesses of the lower resin layer 20 obtained at the above-mentioned 10 locations is defined as the thickness TL (μm) of the lower resin layer 20. The arithmetic mean value of the thicknesses of the outermost resin layer 30 obtained at the above-mentioned 10 locations is defined as the thickness TH (μm) of the outermost resin layer 30.

[0105] [4.10. Preferable Chemical Composition of the Lower Resin Layer 20] The lower resin layer 20 has a higher hardness than the outermost resin layer 30, and has a protective effect of being able to withstand collision or contact with a flying object or the like, the force of which is buffered by the outermost resin layer 30. Such a lower resin layer 20 preferably has the following chemical composition.

[0106] Preferably, the lower resin layer 20 contains an organic resin and an inorganic pigment. The organic resin may be, for example, one or more selected from the group consisting of well-known natural resins and well-known synthetic resins. The organic resin may be, for example, one or more selected from the group consisting of epoxy resins, urethane resins, polyester resins, phenolic resins, polyethersulfone resins, melamine alkyd resins, acrylic resins, polyamide resins, polyimide resins, silicone resins, polyvinyl acetate resins, polyolefin resins, polystyrene resins, vinyl chloride resins, and vinyl acetate resins.

[0107] More preferably, the organic resin is one or more selected from the group consisting of polyester-based resins, urethane-based resins, and melamine-based resins. The metal material 1 is usually used in an indoor or outdoor environment after cold working such as bending. Therefore, the lower resin layer 20 is required to have properties such as ductility, elongation, hardness, chemical resistance, and water resistance. Polyester-based resins and urethane-based resins are excellent in the above-mentioned properties. Furthermore, melamine-based resins are excellent in chemical resistance and hardness.

[0108] The melamine-based resin further reacts with the functional groups of the polyester-based resin and the functional groups of the urethane-based resin to further increase the degree of cross-linking. Therefore, more preferably, the organic resin of the lower resin layer 20 comprises at least one of a polyester-based resin and a urethane-based resin, and a melamine-based resin.

[0109] The inorganic pigment is, for example, BaSO ４ , SiO ２ , ZrO, TiO ２ , and ZnO. If the lower resin layer 20 contains the inorganic pigment, the lower resin layer 20 is densified. As a result, the hardness of the lower resin layer 20 is increased. The particle diameter of the inorganic pigment is preferably small. The particle diameter of the inorganic pigment is preferably 270 nm or less. In this case, the organic resin is densified more uniformly.

[0110] In the lower resin layer 20, the desired hardness HL can be obtained by adjusting the structure of the organic resin described above, the molecular weight of the monomer, oligomer, or polymer, the composition ratio of different types of organic resin, the amount of inorganic pigment added, and the type and amount of additives described below.

[0111] The content of the organic resin in the lower resin layer 20 is preferably 80% or more by mass, more preferably 90% or more, and even more preferably 97% or more.

[0112] [4.11. Preferable Chemical Composition of the Outermost Resin Layer 30] The outermost resin layer 30 has a buffering effect that absorbs external forces caused by the collision of flying objects. Such an outermost resin layer 30 preferably has the following chemical composition.

[0113] Preferably, the outermost resin layer 30 contains an organic resin. The organic resin may be, for example, one or more selected from the group consisting of well-known natural resins and well-known synthetic resins. The organic resin may be, for example, one or more selected from the group consisting of epoxy resins, urethane resins, polyester resins, phenolic resins, polyethersulfone resins, melamine alkyd resins, acrylic resins, polyamide resins, polyimide resins, silicone resins, polyvinyl acetate resins, polyolefin resins, polystyrene resins, vinyl chloride resins, and vinyl acetate resins.

[0114] More preferably, the organic resin is one or more selected from the group consisting of polyester-based resins, urethane-based resins, and melamine-based resins. The polyester-based resin is, for example, polyester, the urethane-based resin is, for example, urethane, and the melamine-based resin is, for example, melamine. As described above, the metal material 1 is typically used in an indoor or outdoor environment after undergoing cold working such as bending. Therefore, like the lower resin layer 20, the outermost resin layer 30 is also required to have properties such as ductility, elongation, hardness, chemical resistance, and water resistance. Polyester-based resins and urethane-based resins are excellent in the above-mentioned properties. Furthermore, melamine-based resins are excellent in chemical resistance and hardness.

[0115] The melamine-based resin further reacts with the functional groups of the polyester-based resin and the urethane-based resin to further increase the degree of cross-linking. Therefore, more preferably, the organic resin of the outermost resin layer 30 is composed of at least one of a polyester-based resin and a urethane-based resin, and a melamine-based resin. The polyester-based resin is, for example, polyester, and the urethane-based resin is, for example, urethane.

[0116] In the outermost resin layer 30, the desired hardness HH can be obtained by adjusting the structure of the organic resin described above, the molecular weight of the monomer, oligomer, or polymer, the composition ratio of different types of organic resin, and the type and amount of additives described below.

[0117] When the outermost resin layer 30 contains an organic resin and an additive, the content of the organic resin in the outermost resin layer 30 is preferably 90% by mass or more, more preferably 95% by mass or more, and even more preferably 97% by mass or more. The content of the additive in the outermost resin layer 30 is preferably 10% by mass or less, more preferably 5% by mass or less, and even more preferably 3% by mass or less. The content of the additive may be 0% or more than 0%.

[0118] [4.12. Additives that can be contained in the lower resin layer 20 and the outermost resin layer 30] Each of the lower resin layer 20 and the outermost resin layer 30 may further contain, as an additive, one or more selected from the group consisting of color pigments, organic resin particles, leveling agents, defoamers, aggregates, and rheology modifiers. The color pigments, organic resin particles, leveling agents, defoamers, aggregates, and rheology modifiers will be described below.

[0119] (1) Regarding Color Pigments Color pigments are fine particles (powder) that are insoluble in water and oil. The color pigments are contained in the lower resin layer 20 or the outermost resin layer 30 to color the lower resin layer 20 or the outermost resin layer 30. Color pigments are well known and may be inorganic pigments or organic pigments. Color pigments are chromatic pigments. A chromatic color refers to a color that has the attributes of hue, lightness, and saturation.

[0120] Preferably, the lower resin layer 20 contains a coloring pigment, and the outermost resin layer 30 does not contain a coloring pigment. As described above, the outermost resin layer 30 has a buffering effect, and the lower resin layer 20 has a protective effect. Therefore, the outermost resin layer 30 is easily deformed when subjected to external forces such as flying objects. On the other hand, the lower resin layer 20 is less likely to deform even when subjected to external forces. If the outermost resin layer 30 does not contain a coloring pigment and the lower resin layer 20 contains a coloring pigment, it is easier to maintain the design properties associated with the coloring pigment.

[0121] When the coloring pigment is an inorganic pigment, the coloring pigment is, for example, one or more selected from the group consisting of neutralized precipitate pigments (sulfates, carbonates, etc.) and calcined pigments (metal sulfides, metal oxides, polyvalent metal composite oxides, etc.). When the coloring pigment is an organic pigment, the coloring pigment is, for example, one or more selected from the group consisting of chlorine pigments, azo pigments (soluble azo lake pigments, insoluble azo pigments, etc.), acid condensation pigments, polycyclic pigments (phthalocyanine pigments, indigo pigments, quinacridone pigments, anthraquinone pigments, etc.), and metal complex pigments (azo chelate pigments, transition metal complex pigments, etc.).

[0122] The color of the color pigment is not particularly limited. Examples of the color pigment include carbon black (C), iron black (Fe ３ O ４ However, the color pigment is not limited to a black pigment, and may be a color pigment of other colors (white, purple-red, yellow, green-blue, red, orange, green, blue, indigo blue, purple, etc.).

[0123] The particle size of the color pigment is not particularly limited. However, the color pigment absorbs visible light to develop color. Therefore, taking into consideration the wavelength of visible light, the preferred lower limit of the particle size of the color pigment is more than 180 nm. The upper limit of the particle size of the color pigment is not particularly limited. The preferred upper limit of the particle size of the color pigment is 1000 nm, more preferably 800 nm, and even more preferably 700 nm.

[0124] (2) Organic Resin Particles Organic resin particles, also known as wax, are, for example, one or more types selected from the group consisting of urethane-based resin particles, acrylic-based resin particles, hard polyethylene-based resin particles, polyethylene-based resin particles, polypropylene-based resin particles, and PTFE (polytetrafluoroethylene) particles.

[0125] Preferably, the organic resin particles satisfy at least one of the following (Configuration 1) and (Configuration 2). (Configuration 1) The hardness of the organic resin particles is higher than that of the base resin. (Configuration 2) The surface free energy of the organic resin particles is lower than that of the base resin, and therefore the friction coefficient of the resin particles is lower than that of the base resin. Here, the base resin refers to the organic resin described in [4.10. Regarding the preferred chemical composition of the lower resin layer 20] and [4.11. Regarding the preferred chemical composition of the outermost resin layer 30] that constitutes the matrix (binder) of the lower resin layer 20 or the outermost resin layer 30. Some of the organic resin particles may protrude outward from the base resin. The organic resin particles are harder or have a lower friction coefficient than the base resin. Therefore, the occurrence of scratches due to collision or contact with flying objects, etc. can be further suppressed.

[0126] (3) Regarding the Leveling Agent: The leveling agent adjusts the surface tension of the outermost resin agent, which is the raw material of the outermost resin layer 30, and smooths the surface of the outermost resin agent after the outermost resin agent is applied. This makes it possible to prevent the occurrence of irregularities or unevenness on the surface of the outermost resin layer 30. Examples of the leveling agent include a fluorine-based surfactant, a silicone-based surfactant, and an acrylic resin.

[0127] (4) Antifoaming Agents Antifoaming agents suppress bubbles from forming in the lower layer resin agent (slurry) and the outermost resin agent. Examples of antifoaming agents include silicone-based antifoaming agents, non-silicone-based antifoaming agents, mineral oil-based antifoaming agents, and glycerin esters.

[0128] (5) Regarding the Aggregate The aggregate is a fine inorganic particle (powder) that is insoluble in water and oil. When contained in the lower resin layer 20 and the outermost resin layer 30, the aggregate increases the volume of the paint and suppresses deformation of the resin (lower resin layer 20 or outermost resin layer 30). The aggregate is, for example, one or more types selected from the group consisting of silica and talc. However, if the secondary particle diameter of the aggregate is larger than the wavelength of visible light (270 nm), the visible light is scattered. In this case, sufficient design properties may not be obtained in the metal material 1. Therefore, the preferred secondary particle diameter of the aggregate is 270 nm or less.

[0129] (6) Rheology Modifiers Rheology modifiers are also called thickeners. Rheology modifiers adjust the viscosity of the lower layer resin agent, which is the raw material for the lower layer resin layer 20, and the outermost resin agent, which is the raw material for the outermost resin layer 30. This makes it easy to adjust the adhesion amounts of the lower layer resin agent and the outermost resin agent when applying them. Examples of rheology modifiers include associative viscoelasticity modifiers and polymeric viscoelasticity modifiers whose main component is acrylic acid.

[0130] 5. Optional Configuration of Metal Material 1> As shown in Fig. 4, the metal material 1 may further include a chemical conversion coating 40 between the metal surface S (the surface 10S of the metal substrate 10 or the surface 11S of the plating layer 11) and the lower resin layer 20. In other words, the chemical conversion coating 40 is an optional configuration and may not be provided. The chemical conversion coating 40 will be described below.

[0131] [5.1. Regarding the Chemical Conversion Coating 40] The chemical conversion coating 40 further enhances the corrosion resistance of the metal material 1. The chemical conversion coating 40 also enhances the adhesion between the metal surface S and the lower resin layer 20. The composition of the chemical conversion coating 40 may be a well-known composition. Preferably, the chemical conversion coating 40 contains an organosilicon compound, a specific inorganic compound containing one or more of V, P, Zr, and Ti, and a fluorine compound.

[0132] (1) Organosilicon Compounds Organosilicon compounds are compounds in which silicon (Si) and an organic group are bonded. The type of organosilicon compound is not particularly limited.

[0133] Preferably, the organosilicon compound is a silane coupling agent. The silane coupling agent has a reactive functional group and a hydrolyzable group. The reactive functional group of the silane coupling agent bonds with the organic material (organic resin), and the hydrolyzable group bonds with the inorganic material. Therefore, the silane coupling agent can improve adhesion to the metal surface S while also improving adhesion to the lower resin layer 20.

[0134] (2) Regarding the specific inorganic compound The specific inorganic compound is a compound containing one or more elements selected from the group consisting of V, P, Zr, and Ti. The specific inorganic compound enhances the corrosion resistance of the metal material 1.

[0135] (2-1) V Compounds Vanadium compounds enhance corrosion resistance. There are no particular limitations on the vanadium compound as long as it contains V.

[0136] The vanadium compound is, for example, vanadium pentoxide V ２ O ５ , metavanadate HVO ３ , ammonium metavanadate, sodium metavanadate, vanadium oxytrichloride VOCl ３ , vanadium trioxide V ２ O ３ , vanadium dioxide VO ２ , vanadium oxysulfate VOSO ４ , vanadium oxyacetylacetonate VO(OC(=CH ２ ) CH ２ COCH ３ ) ２ , vanadium acetylacetonate V(OC(=CH ２ ) CH ２ COCH ３ ) ３ , and vanadium trichloride VCl ３ The vanadium compound may also be one or more selected from the group consisting of: a pentavalent vanadium compound produced by reducing a pentavalent vanadium compound to a tetravalent to divalent vanadium compound with an organic compound having at least one functional group selected from the group consisting of a hydroxyl group, a carbonyl group, a carboxyl group, a primary to tertiary amino group, an amide group, a phosphoric acid group, and a phosphonic acid group.

[0137] (2-2) Regarding P Compounds P compounds significantly improve corrosion resistance. Examples of P compounds include one or more compounds selected from the group consisting of phosphoric acid, ammonium phosphate, potassium phosphate, and sodium phosphate. Preferably, the P compound is phosphoric acid. When phosphoric acid is used, corrosion resistance is further improved.

[0138] (2-3) Zr Compounds Zr compounds are compounds containing Zr, such as Zr oxides, hydroxides, complex compounds, and salts with inorganic or organic acids. Zr compounds react easily with reactive functional groups. As a result, the Zr compounds promote the curing and crosslinking reaction of the chemical conversion coating 40, thereby increasing the density of the chemical conversion coating 40. As a result, corrosion resistance is significantly improved.

[0139] For example, the Zr compound is zirconyl nitrate (ZrO(NO ３ ) ２ ), zirconyl acetate, zirconyl sulfate, ammonium zirconium carbonate {(NH ４ ) ２ [Zr(CO ３ ) ２ (OH) ２ ]}, and zirconium acetate.

[0140] (2-4) Ti Compounds Like Zr compounds, Ti compounds easily react with reactive functional groups. Therefore, the Ti compounds harden the chemical conversion coating 40 and increase the density of the chemical conversion coating 40. As a result, the corrosion resistance of the metal material 1 is significantly improved.

[0141] The Ti compound is a compound containing Ti, such as an oxide, hydroxide, complex compound, or salt with an inorganic or organic acid of Ti. For example, the Ti compound is titanyl sulfate (TIOSO ４ ), titanium lactate, diisopropoxytitanium bisacetylacetone {(C ５ H ７ O ２ ) ２ Ti[OCH(CH ３ ) ２ ] ２ and a reaction product of lactic acid with titanium alkoxide.

[0142] (3) Regarding Fluorine Compounds Fluorine compounds enhance the corrosion resistance of the chemical conversion coating 40. There are no particular limitations on the fluorine compound as long as it is a compound containing fluorine. For example, the fluorine compound is one or more compounds selected from the group consisting of hydrofluoric acid, hydrofluoroboric acid, hydrosilicofluoroacid, fluorides thereof, and complex fluoride salts.

[0143] The Zr compound and the fluorine compound may be integrated together. Specifically, the chemical conversion coating 40 may contain the Zr compound and the fluorine compound as separate compounds, or may contain a compound containing Zr and fluorine. For example, fluorozirconium acid acts as both a Zr compound and a fluorine compound. Therefore, fluorozirconium acid includes a Zr compound and a fluorine compound. Furthermore, the Ti compound and the fluorine compound may be integrated together. Specifically, the chemical conversion coating 40 may contain the Ti compound and the fluorine compound as separate compounds, or may contain a compound containing Ti and fluorine. For example, fluorotitanium acid acts as both a Ti compound and a fluorine compound. Therefore, fluorotitanium acid includes a Ti compound and a fluorine compound.

[0144] 6. Effects of Metal Material 1 The metal material 1 having the above configuration has excellent corrosion resistance and excellent scratch resistance. Therefore, the metal material 1 can be widely used in, for example, indoor electrical equipment applications, outdoor automotive applications, and building material applications.

[0145] 7. Manufacturing Method of Metal Material 1 The metal material 1 of this embodiment can be manufactured, for example, by the following method. An example of a manufacturing method of the metal material 1 will be described below. The example of a manufacturing method of the metal material 1 includes the following steps: (Step 1) Metal material preparation step (Step 2) Plating layer formation step (Step 3) Texture formation step (Step 4) Chemical conversion coating formation step (Step 5) Lower resin layer formation step (Step 6) Outermost resin layer formation step Here, steps 2 to 4 are optional steps. In other words, each of steps 2 to 4 may be performed as needed. Each step will be described below.

[0146] [(Step 1) Metal Material Preparing Step] In the metal material preparing step, the above-described metal substrate 10 is prepared. As described above, the metal substrate 10 is, for example, a metal plate, a metal bar, or a metal pipe.

[0147] [(Step 2) Plating Layer Forming Step] The plating layer forming step is an optional step. The plating layer forming step is performed when forming a plating layer 11 on the metal substrate 10. Therefore, if the plating layer 11 is not formed on the metal substrate 10, the plating layer forming step is not performed.

[0148] In the plating layer forming step, the plating layer 11 is formed on the metal substrate 10 by electroplating or hot-dip plating. Known plating methods may be used for the electroplating and hot-dip plating.

[0149] When the plating layer 11 is a zinc-based plating layer, the plating layer 11 is formed by, for example, the following electrogalvanizing method or hot-dip galvanizing method.

[0150] (Electrogalvanizing Method) When forming a zinc-based plating layer by electrogalvanizing, the electrogalvanizing method may be performed by a known method. In this specification, the term "electrogalvanizing method" also includes electrogalvanizing methods such as zinc alloy plating. The plating solution used in the electrogalvanizing method may be a known electrogalvanizing solution. Examples of electrogalvanizing solutions include sulfate baths, chloride baths, zincate baths, cyanide baths, pyrophosphate baths, boric acid baths, citric acid baths, other complex baths, and combinations thereof. The electrogalvanizing solution may contain, in addition to Zn ions, one or more single ions or complex ions selected from the group consisting of Fe, Ni, Co, Cr, and C. Furthermore, organic additives may be added to the electrogalvanizing solution or electrogalvanizing solution to achieve desired effects such as leveling or increased hardness.

[0151] (Hot-dip galvanizing method) When forming the plating layer 11 consisting of a zinc-based plating layer by hot-dip galvanizing, the hot-dip galvanizing method may be performed by a known method. A known plating bath may be used in the hot-dip galvanizing method. The plating bath may contain, for example, Al, with the balance being Zn and impurities. The impurities may be, for example, Fe. In addition to Zn, Al, and Fe, the plating bath may further contain one or more elements selected from the group consisting of Co, Cr, Cu, Ni, P, Si, Sn, Mg, Mn, Mo, V, W, Zr, Ca, Y, La, Ce, Bi, In, Ti, V, Nb, Cu, Mn, Sr, Sb, Pb, and B.

[0152] Through the above manufacturing steps, the plating layer 11 is formed on the metal substrate 10 .

[0153] [(Step 3) Texture Forming Step] The texture forming step is an optional step. The texture forming step is performed when a texture TX is formed on the metal surface S (the surface 10S of the metal substrate 10 or the surface 11S of the plating layer 11). In the texture forming step, the metal surface S is textured to form the texture TX.

[0154] When the texture TX is a hairline, a known hairline processing is performed. Examples of hairline processing include a method of forming a hairline by polishing the surface with a known abrasive belt, a method of forming a hairline by polishing the surface with a known abrasive brush, and a method of forming a hairline by rolling and transferring the hairline with a roll to which a hairline shape has been imparted. The length, depth, and frequency of the hairline can be adjusted by adjusting the grain size of the known abrasive belt, the grain size of the known abrasive brush, or the surface shape of the roll. Note that, from the viewpoint of surface quality, the hairline processing method of forming a hairline by polishing the surface with an abrasive belt or an abrasive brush is preferred.

[0155] When the texture TX is an uneven shape such as an embossment, dots, or vibration, a well-known transfer method using a roll may be performed. Specifically, a roll on which an uneven texture TX such as an embossment is formed is prepared. The prepared roll is pressed against a metal surface S to transfer the uneven shape formed on the roll to the metal surface S. By the above steps, an uneven shape such as an embossment can be formed on the metal surface S.

[0156] (Step 4) Chemical Conversion Coating Formation Step The chemical conversion coating formation step is an optional step. In other words, the chemical conversion coating formation step does not have to be performed. In the chemical conversion coating formation step, a chemical conversion coating 40 is formed on the metal surface S. The production line used in the chemical conversion coating formation step includes a conveying line and, from upstream to downstream of the conveying line, a paint application device and a baking furnace.

[0157] A metal substrate 10 having a metal surface S is transported along the transport line. A coating material application device is arranged on the transport line. The coating material application device applies a chemical conversion coating agent, which is a raw material for the chemical conversion coating 40, to the metal surface S. The coating material application device is, for example, a well-known coater. Examples of well-known coaters include a die coater, a roll coater, and a curtain coater.

[0158] The chemical conversion coating agent contains an organosilicon compound, a specific inorganic compound containing one or more of V, P, Zr, and Ti, and a fluorine compound.

[0159] The baking furnace is disposed on the conveying line downstream of the coating device. The baking furnace dries and bakes the chemical conversion coating agent applied to the metal surface S by the coating device to form the chemical conversion coating 40. The maximum temperature reached in the baking furnace (Peak-Metal-Temperature: PMT) (°C) is set to, for example, 50 to 250°C.

[0160] [(Step 5) Lower Resin Layer Forming Step] In the lower resin layer forming step, the lower resin layer 20 is formed on the metal surface S or the surface of the chemical conversion coating 40. The production line used in the lower resin layer forming step includes a conveying line and, from upstream to downstream of the conveying line, a paint application device and a baking furnace.

[0161] A metal substrate 10 including a metal surface S or a chemical conversion coating 40 is transported along the transport line. A paint application device is arranged on the transport line. The paint application device applies a lower layer resin agent, which is a raw material for the lower layer resin layer 20, to the metal surface S or the surface of the chemical conversion coating 40. The paint application device is, for example, a well-known coater. The lower layer resin agent is an agent that is a raw material for the lower layer resin layer 20. The lower layer resin agent contains an organic resin and an inorganic pigment.

[0162] The baking furnace is disposed on the conveying line downstream of the coating material application device. The baking furnace dries and bakes the lower layer resin agent applied by the coating material application device to the metal surface S or the surface of the chemical conversion coating 40 to form the lower layer resin layer 20. The maximum temperature PMT (°C) reached in the baking furnace is set to, for example, 150 to 250°C.

[0163] [(Step 6) Outermost Resin Layer Forming Step] In the outermost resin layer forming step, the outermost resin layer 30 is formed on the surface of the lower resin layer 20. The production line used in the outermost resin layer forming step includes a conveying line, and, from upstream to downstream of the conveying line, a paint application device and a baking furnace.

[0164] The metal substrate 10 including the lower resin layer 20 is transported along the transport line. A paint application device is arranged on the transport line. The paint application device applies an outermost resin agent, which is a raw material for the outermost resin layer 30, to the surface of the lower resin layer 20. The paint application device is, for example, a well-known coater. The outermost resin agent is an agent that is a raw material for the outermost resin layer 30. The outermost resin agent contains an organic resin.

[0165] The baking furnace is disposed on the conveying line downstream of the coating device. The baking furnace dries and bakes the outermost resin agent applied to the surface of the lower resin layer 20 by the coating device to form the outermost resin layer 30. The maximum temperature PMT (°C) of the baking furnace is set to, for example, 150 to 250°C.

[0166] In steps 5 and 6, the hardness HL of the lower resin layer 20 and the hardness HH of the outermost resin layer 30 are adjusted so that the manufactured metal material 1 satisfies formula (1). In steps 5 and 6, the thickness TL of the lower resin layer 20 and the thickness TH of the outermost resin layer 30 are further adjusted so that the manufactured metal material 1 satisfies formula (2). Preferably, in steps 5 and 6, the thickness TL of the lower resin layer 20 and the thickness TH of the outermost resin layer 30 are further adjusted so that the manufactured metal material 1 satisfies formula (3) and formula (4).

[0167] The metal material 1 of this embodiment is manufactured by the above manufacturing steps. The metal material 1 may be manufactured by other manufacturing methods. The above manufacturing method is one example of a method for manufacturing the metal material 1.

[0168] The effects of the metal material 1 of this embodiment will be described more specifically below with reference to examples.

[0169] [Production of Metal Materials] Metal materials with test numbers shown in Table 1 were produced by the following production process. All of the metal materials were metal plates.

[0170]

[0171] [Metal Material Preparation Step] Metal plates (metal materials) of the metal types listed in the "Metal Substrate" column of Table 1 were prepared. "Steel" in the "Metal Substrate" column of Table 1 means that the metal plate was a steel plate (corresponding to SPHC in the JIS standard). "Al alloy" means that the metal plate was an aluminum alloy plate (corresponding to A1014P in the JIS standard). "Al" means that the metal plate was an aluminum plate (corresponding to A1050P in the JIS standard).

[0172] [Plating Layer Forming Step] In test numbers 6 to 50 and 52 to 56, a plating layer was formed on the metal plate.

[0173] In test numbers 6 to 9, 52, and 53, a Zn plating layer was formed as the plating layer by a well-known electroplating method (indicated as "Zn plating" in the "Plating layer" column in Table 1). The coating weight of the plating layer was 35 g / m ２ The chemical compositions of the plating layers were measured by the method described above in [3.1. Method for measuring the chemical composition of plating layer 11]. As a result, all of the plating layers with these test numbers had a chemical composition consisting of Zn.

[0174] In test numbers 10 to 38, 49, 50, and 54 to 56, a Zn-Ni plating layer was formed as the plating layer by a well-known electroplating method (indicated as "Zn-Ni plating" in the "Plating layer" column in Table 1). The coating weight of the plating layer was 35 g / m ２ The chemical compositions of the plating layers were measured by the method described in [3.1. Method for measuring the chemical composition of plating layer 11] above. As a result, the plating layers of these test numbers all had a chemical composition in which the Ni content was 10 to 15% by mass, with the remainder being Zn.

[0175] In test number 39, a Zn-Fe plating layer was formed as the plating layer by a well-known electroplating method (indicated as "Zn-Fe plating" in the "Plating layer" column in Table 1). The coating weight of the plating layer was 35 g / m ２The chemical composition of the plating layer was measured by the method described in [3.1. Method for measuring chemical composition of plating layer 11] above. As a result, the plating layer of Test No. 39 had a chemical composition in which the Fe content was 15% by mass, with the remainder being Zn.

[0176] In test number 40, a Zn—Co plating layer was formed as the plating layer by a well-known electroplating method (indicated as “Zn—Co plating” in the “Plating layer” column in Table 1). The coating weight of the plating layer was 35 g / m ２ The chemical composition of the plating layer was measured by the method described in [3.1. Method for measuring chemical composition of plating layer 11] above. As a result, the plating layer of Test No. 40 had a chemical composition in which the Co content was 2.0% by mass, with the remainder being Zn.

[0177] In test number 41, a Zn-Al plating layer was formed as the plating layer by a well-known hot dip plating method (indicated as "Zn-Al plating" in the "Plating layer" column in Table 1). The coating weight of the plating layer was 90 g / m ２ The chemical composition of the plating layer was measured by the method described in [3.1. Method for measuring chemical composition of plating layer 11] above. As a result, the plating layer of Test No. 41 had a chemical composition in which the Al content was 5.0% by mass, with the remainder being Zn.

[0178] In test number 42, a Zn-Al coating layer was formed by a known hot-dip galvanizing method, and the Zn-Al coating layer was further alloyed by a known hot-alloying method to form a Zn-Fe-Al coating layer (shown as "Zn-Fe-Al coating" in the "Coating layer" column in Table 1). The coating weight of the coating layer was 45 g / m ２ The chemical composition of the plating layer was measured by the method described in [3.1. Method for measuring chemical composition of plating layer 11] above. As a result, the plating layer of Test No. 42 had a chemical composition in which the Fe content was 13.0% by mass, the Al content was 0.1% by mass, and the balance was Zn.

[0179] In test number 43, an Al-Si plating layer was formed as the plating layer by a well-known hot dip plating method (indicated as "Al-Si plating" in the "Plating layer" column in Table 1). The coating weight of the plating layer was 60 g / m ２The chemical composition of the plating layer was measured by the method described in the above-mentioned [3.1. Method for measuring the chemical composition of plating layer 11]. As a result, the plating layer of Test No. 43 had a chemical composition in which the Si content was 9% by mass, with the remainder being Al.

[0180] In test numbers 44 to 48, a Zn-Al-Mg plating layer was formed as the plating layer by a well-known hot-dip plating method (indicated as "Zn-Al-Mg plating" in the "Plating layer" column in Table 1). The coating weight of the plating layer was 90 g / m ２ The chemical compositions of the plating layers were measured by the method described in [3.1. Method for measuring chemical composition of plating layer 11] above. As a result, the plating layers of these test numbers all had a chemical composition in which the Al content was 11.0 to 19.0% by mass, the Mg content was 3.0 to 6.0% by mass, and the balance was Zn.

[0181] [Texture Forming Step] Textures were formed on the surfaces of the metal substrates of test numbers 3 and 5, and on the surfaces of the plating layers of test numbers 8, 9, 11 to 45, 49, 50, and 52 to 56. In Table 1, "Hairline" in the "Texture" column means that a hairline was formed as the texture. "Embossed" means that an embossment was formed as the texture. The hairline processing was formed using an abrasive brush. The embossment was formed on the plating layer using a roll.

[0182] [Chemical Conversion Coating Formation Step] A chemical conversion coating was formed on the metal substrate or plating layer for test numbers 2, 3, 7 to 45, 49, 50, and 52 to 56. The chemical conversion coating agents were prepared as follows for all test numbers. A silane coupling agent (A): 3-aminopropyltrimethoxysilane, and a silane coupling agent (B): 3-glycidoxypropyltrimethoxysilane were prepared and added to water adjusted to a pH of 4 at a solids mass ratio [(A) / (B)] of 1.0, and stirred for a predetermined time to produce an organosilicon compound. The produced organosilicon compound was mixed with phosphoric acid, a phosphate compound, and vanadium oxysulfate (VOSO), a V compound, to produce a silane coupling agent (A): 3-aminopropyltrimethoxysilane. ４A chemical conversion coating agent containing fluorine-containing zirconium compounds, a Zr compound, and zirconium hydrofluoric acid was prepared. The prepared chemical conversion coating agent was used to form a chemical conversion coating on a metal substrate or a plating layer.

[0183] [Lower Resin Layer Formation Step] A lower resin layer was formed on the metal substrate, plating layer, or chemical conversion coating of each test number using a resin agent with the agent type code listed in the "Lower Resin Layer" column in Table 1. Table 2 shows the composition of the resin agent.

[0184]

[0185] The structure, molecular weight, ratio, and amount of additive of each organic resin for each drug type in Table 2 were appropriately adjusted so that the hardness HL of the lower resin layer was adjusted to the value shown in the "HL (GPa)" column of the "lower resin layer" column in Table 1. ４ The content of each of the beads was 2% when the solid content of the corresponding drug was 100% by mass, and the content of carbon black was 1% by mass when the solid content of the corresponding drug was 100% by mass.

[0186] The resin agent was applied to the metal layer or the chemical conversion coating using a coater, and then dried in a baking oven. The maximum temperature PMT of the baking oven was in the range of 150 to 250°C. Through the above steps, a lower resin layer was formed.

[0187] [Outermost Resin Layer Formation Step] After forming the lower resin layer, an outermost resin layer was formed on the surface of the lower resin layer using a resin agent having the agent type symbol listed in the "Outermost Resin Layer" column of Table 1. The structure, molecular weight, ratio, and additive amount of the organic resin for each agent type in Table 2 were appropriately adjusted to adjust the hardness HH of the outermost resin layer to the value listed in the "HH (GPa)" column of the "Outermost Resin Layer" column of Table 1.

[0188] The resin agent was applied to the lower resin layer using a coater, and then dried in a baking oven. The maximum temperature PMT of the baking oven was in the range of 150 to 250°C. The outermost resin layer was formed by the above process. Metal plates (metal materials) with each test number were manufactured by the above manufacturing process.

[0189] [Evaluation Tests] The following evaluation tests were carried out on the metal sheets with each test number: (Test 1) Hardness and thickness measurement test of lower resin layer and outermost resin layer (Test 2) Scratch resistance evaluation test (Test 3) Corrosion resistance evaluation test (Test 4) Visibility evaluation test (Test 5) Design evaluation test Tests 1 to 5 are described below.

[0190] [(Test 1) Hardness and Thickness Measurement Test of Lower Resin Layer and Outermost Resin Layer] According to the method described above in [4.9. Method for Measuring the Hardness HL and Thickness TL of the Lower Resin Layer 20, and the Hardness HH and Thickness TH of the Outermost Resin Layer 30], the hardness HL (GPa), thickness TL (μm) of the lower resin layer, hardness HH (GPa), and thickness TH (μm) of the outermost resin layer were determined for each test number. A Hysitron TI 980 nanoindenter manufactured by Bruker was used. The obtained values ​​are shown in the "HL (GPa)", "TL (μm)", "HH (GPa)", and "TH (μm)" columns in Table 1, respectively.

[0191] [(Test 2) Scratch Resistance Evaluation Test] The scratch resistance of the metal plate of each test number was evaluated by the following method. A test specimen (50 mm × 100 mm × plate thickness) was taken from the metal plate of each test number. The specimen was attached and fixed to the sample stage of a friction tester equipped with a diamond needle with a tip diameter of 0.09 mmR. The friction tester used was a Tripogear Type: 14FW product name manufactured by Shinto Scientific Co., Ltd.

[0192] The diamond needle was brought into contact perpendicularly with the surface of the outermost resin layer of the test piece. With the diamond needle in contact with the surface of the outermost resin layer of the test piece, the sample stage on which the test piece was fixed was slid at a scratching speed of 60 mm / sec. At this time, the load applied to the diamond needle was changed, and the presence or absence of scratches was visually confirmed. The scratch resistance of the metal plate was evaluated as follows based on the load at which scratches were visually confirmed. The obtained results are shown in the "Scratch Resistance" column in Table 1. Scratch rating 1: Scratches were visually confirmed at a load of less than 30 gf. Scratch rating 2: Scratches were visually confirmed at a load of 30 gf or more but less than 70 gf. Scratch rating 3: Scratches were visually confirmed at a load of 70 gf or more but less than 120 gf. Scratch rating 4: Scratches were visually confirmed at a load of 120 gf or more. A scratch rating of 2 or more was evaluated as having excellent scratch resistance. The evaluation results are shown in the "Scratch Resistance" column in Table 1.

[0193] [(Test 3) Corrosion Resistance Evaluation Test] The corrosion resistance (long-term corrosion resistance) of the metal plates with each test number was evaluated by the following method. Test specimens measuring 75 mm x 100 mm x thickness were taken from the metal plates with each test number. The end faces and back faces of the test specimens were protected with tape seals. Then, a salt spray test using 5% NaCl maintained at 35°C was conducted in accordance with JIS Z 2371 (2015). The test was conducted for 240 hours, and the rust occurrence rate (%) after the test was determined. The obtained rust occurrence rate was evaluated as follows: A: The rust occurrence rate was less than 1%. B: The rust occurrence rate was 1% or more but less than 5%. C: The rust occurrence rate was 5% or more. A rating of A or B indicated that excellent corrosion resistance was obtained. A rating of C indicated that sufficient corrosion resistance was not obtained. The evaluation results are shown in the "Corrosion Resistance" column in Table 1.

[0194] [(Test 4) Visibility Evaluation Test] The visibility of the metal base of the textured metal material was evaluated using the following method. The metal material with each test number was placed in an environment equivalent to sunlight on a clear morning (illuminance of approximately 65,000 lux). Then, it was confirmed whether the metal base of the surface of the metal base material or the surface of the plating layer was visible from the surface of the metal material, through the outermost resin layer and the lower resin layer. The following evaluation was made based on the number of people who judged the metal base to be visible. A: All 10 people judged it to be visible. B: 7 or more but less than 10 people judged it to be visible. C: Less than 7 people judged it to be visible. A rating of A or B was evaluated as sufficient visibility being obtained. A rating of C was evaluated as insufficient visibility being obtained. The evaluation results are shown in the "Visibility" column in Table 1.

[0195] [(Test 5) Design Evaluation Test] The design of the texture of the textured metal material was evaluated using the following method. First, a metal material with a test number on which a texture was formed was placed outdoors at an angle of 60° to the horizontal. The metal material was placed so that the texture faced upward outdoors. Next, an observer visually observed the metal material from a position 1 m away from the metal material's placement on the ground, facing the metal material. The observer's line of sight was at the same height as the metal material. A total of 10 observers visually observed the metal material and performed a sensory evaluation to determine whether the design was excellent. The following evaluation was performed based on the number of observers who judged the design to be excellent. A: 9 or more observers judged the design to be excellent. B1: 7 to 8 observers judged the design to be excellent. B2: 5 to 6 observers judged the design to be excellent. C: Less than 5 observers judged the design to be excellent. A rating of A, B1, or B2 was used to evaluate the design as excellent. When the evaluation was C, it was evaluated that sufficient design was not obtained. The evaluation results are shown in the "Design" column in Table 1.

[0196] [Evaluation Results] Referring to Table 1, for the metal materials of test numbers 1 to 45, the hardness HL of the lower resin layer was 0.18 GPa or more. In addition, the hardness HH of the outermost resin layer satisfied formula (1). Furthermore, the thickness TL of the lower resin layer and the thickness TH of the outermost resin layer satisfied formula (2). As a result, for these test numbers, the scratch rating in the scratch resistance evaluation test was 2 or more, and excellent scratch resistance was obtained. Furthermore, the corrosion resistance evaluation test was rated B or more, and excellent corrosion resistance was obtained.

[0197] Of test numbers 1 to 45, in test numbers 20, 23, 29, and 38 excepted, the thickness TL of the lower resin layer was 0.5 μm or more, the hardness HH of the outermost resin layer was 0.13 GPa or more, the thickness TH of the outermost resin layer was 2.0 μm or more, and TH / TL was 1.3 or more. Therefore, the scratch rating in the scratch resistance evaluation test was 3 or more, and the scratch resistance was further excellent.

[0198] Of the test numbers 3, 5, 8, 9, and 11 to 45 in which textures were formed, TL+TH was 20.0 or less for the test numbers other than test numbers 19 and 35. Therefore, the design properties were even better for these test numbers.

[0199] On the other hand, in test numbers 46 and 49, a resin layer corresponding to the lower resin layer was not formed, and therefore the scratch rating in the scratch resistance evaluation test was 1, indicating that sufficient scratch resistance was not obtained.

[0200] In test numbers 47 and 50, a resin layer corresponding to the outermost resin layer was not formed, and therefore the scratch rating in the scratch resistance evaluation test was 1, indicating that sufficient scratch resistance was not obtained.

[0201] In test numbers 48 and 56, the thickness TL of the lower resin layer and the thickness TH of the outermost resin layer did not satisfy formula (2). Therefore, the corrosion resistance evaluation test was rated C, and sufficient corrosion resistance was not obtained.

[0202] In test numbers 51, 53, and 55, the hardness HH of the outermost resin layer did not satisfy formula (1), and therefore the scratch rating in the scratch resistance evaluation test was 1, indicating that sufficient scratch resistance was not obtained.

[0203] In test numbers 52 and 54, the hardness HL of the lower resin layer was less than 0.18 GPa. Therefore, the scratch rating in the scratch resistance evaluation test was 1, and sufficient scratch resistance was not obtained.

[0204] The embodiments of the present disclosure have been described above. However, the above-described embodiments are merely examples for implementing the present disclosure. Therefore, the present disclosure is not limited to the above-described embodiments, and can be implemented by appropriately modifying the above-described embodiments within the scope of the present disclosure.

[0205] REFERENCE SIGNS LIST 1 Metal material 10 Metal substrate 11 Plating layer 20 Lower resin layer 30 Outermost resin layer

Claims

1. A metal material comprising: a metal substrate; a lower resin layer formed on the metal substrate; and an outermost resin layer formed as an outermost layer on the lower resin layer, wherein the hardness HL of the lower resin layer is 0.18 GPa or more, the hardness HH of the outermost resin layer satisfies formula (1), and the thickness TL (μm) of the lower resin layer and the thickness TH (μm) of the outermost resin layer satisfy formula (2). HH / HL<0.90 (1) TL+TH>3.0 (2) 2. The metal material according to claim 1, wherein the hardness HH of the outermost resin layer is 0.13 GPa or more.

3. The metal material according to claim 1, wherein the thickness TL of the lower resin layer is 0.5 μm or more.

4. The metal material according to claim 1, wherein the thickness TH of the outermost resin layer is 2.0 μm or more.

5. The metal material according to claim 1, wherein the thickness TL and the thickness TH satisfy the formula (3): TL+TH≦20.0 (3) 6. The metal material according to claim 1, wherein the thickness TL and the thickness TH satisfy the formula (4): TH / TL≧1.3 (4) 7. The metal material according to claim 1, further comprising a plating layer formed on the metal base material, and the lower resin layer is formed on the plating layer.

8. The metallic material according to claim 7, wherein the metallic substrate is a steel material, and the plating layer is made of one or more selected from the group consisting of Zn plating, Zn-Ni alloy plating, Zn-Fe plating, Zn-Co plating, Zn-Al plating, Zn-Fe-Al plating, Al-Si plating, and Zn-Al-Mg plating.

9. The metal material according to claim 1, wherein the lower resin layer is made of an organic resin selected from the group consisting of polyester, urethane, and melamine, and BaSO ４ , SiO ２ , ZrO, TiO ２ and one or more inorganic pigments selected from the group consisting of ZnO.

10. The metal material according to claim 1, wherein the outermost resin layer contains at least one organic resin selected from the group consisting of polyester and melamine.

11. The metal material according to claim 1, wherein the surface of the metal material is textured.

12. The metal material according to claim 7, wherein the plating layer has a texture formed on the surface.

13. The metal material according to claim 11 or 12, wherein the texture is a hairline.

14. The metal material according to claim 1, further comprising a chemical conversion coating formed on said metal base material, and said lower resin layer being formed on said chemical conversion coating.

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