Method for manufacturing metal member with coating film, and metal member with coating film

Abstract

To provide a method for manufacturing a metal member with a coating film which can manufacture a metal member with a coating film in a saved space at a low equipment cost.SOLUTION: A method for manufacturing a metal member with a coating film includes: a first step of magnetizing at least one of a magnetizable metal member and a coating material containing magnetizable metal powder; a second step of bonding the coating material containing the metal powder onto the surface of the metal member, by magnetic force; and a third step of curing the coating material containing the metal powder bonded to the surface of the metal member.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present disclosure relates to a method for producing a coated metal component, and to a coated metal component. [Background technology]

[0002] Conventionally, methods for producing coated metal components for the purpose of preventing rust or imparting design properties include spray coating, in which a liquid paint is sprayed onto the metal component, dip coating, in which the metal component is immersed in a liquid paint, as well as electrostatic coating of powder paint and fluidized bed immersion methods.

[0003] For example, Patent Document 1 discloses "an electrostatic coating method for coating a substrate, the substrate including an area having electrical conductivity, the method comprising the steps of: suppressing the generation of an electrostatic field between a coating source and the substrate and suppressing the generation of free ions; and discharging charged paint from the coating source to apply the paint to the substrate." [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2013-066817 A Summary of the Invention [Problem to be solved by the invention]

[0005] However, the above-mentioned conventional methods require a large-sized spray device or immersion tank, etc., and have problems in terms of securing space for coating and equipment costs.

[0006] Therefore, an object of the present disclosure is to provide a method for producing a coated metal component that can produce a coated metal component in a small space and at low equipment costs. Another object of the present disclosure is to provide a coated metal component having a coating that contains metal powder and is suppressed from sagging. [Means for solving the problem]

[0007] Means for solving the above problems include the following aspects. <1> A first step of magnetizing at least one of a magnetizable metal member and a paint containing magnetizable metal powder; a second step of applying the paint containing the metal powder to the surface of the metal member by magnetic force; A third step of hardening the paint containing the metal powder attached to the surface of the metal member; A method for producing a coated metal member, comprising: <2> The method further includes a step of demagnetizing the metal member after the third step. <1> A method for producing the coated metal member according to claim 1. <3> The second step further includes a step of rotating the metal member. <1> A method for producing the coated metal member according to claim 1. <4> The metal powder is iron tetraoxide powder. <1> A method for producing the coated metal member according to claim 1. <5> A metal member; A coating provided on a surface of the metal member and containing 5 to 30 mass % of metal powder; A coated metal member having the above structure. Effect of the Invention

[0008] According to the present disclosure, a method for producing a coated metal component is provided that can produce a coated metal component in a small space and with low equipment costs. The present disclosure also provides a coated metal component having a coating that contains metal powder and is suppressed from sagging. [Brief description of the drawings]

[0009] [Figure 1]Fig. 1 is a schematic diagram showing an example of a method for producing a coated metal member according to the present disclosure. Fig. 1(a) is a schematic diagram showing an example of a first step of the method for producing a coated metal member according to the present disclosure. Fig. 1(b) is a schematic diagram showing an example of a second step of the method for producing a coated metal member according to the present disclosure. Fig. 1(c) is a schematic diagram showing an example of a third step of the method for producing a coated metal member according to the present disclosure. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] An example of the present disclosure will now be described. The description is for illustrating the embodiments of the present disclosure, and is not intended to limit the scope of the present disclosure.

[0011] In the present disclosure, a numerical range indicated using "~" indicates a range that includes the numerical values ​​before and after "~" as the minimum and maximum values, respectively. In the numerical ranges described stepwise in the present disclosure, the upper or lower limit value described in one numerical range may be replaced with the upper or lower limit value of another numerical range described stepwise. In addition, in the numerical ranges described in the embodiments of the present disclosure, the upper or lower limit value of the numerical range may be replaced with a value shown in the examples.

[0012] In the present disclosure, the term "step" includes not only an independent step, but also a step that cannot be clearly distinguished from other steps, as long as the intended purpose of the step is achieved.

[0013] In the present disclosure, when an embodiment is described with reference to the drawings, the configuration of the embodiment is not limited to the configuration shown in the drawings. In addition, the size of the members in each drawing is conceptual, and the relative relationship between the sizes of the members is not limited to this.

[0014] In the present disclosure, each component may contain a plurality of corresponding substances. In the present disclosure, when the amount of each component in a composition is mentioned, if a plurality of substances corresponding to each component are present in the composition, the total amount of the plurality of substances present in the composition is meant, unless otherwise specified.

[0015] In this disclosure, the "magnetizable metal member" may be simply referred to as the "metal member."

[0016] In this disclosure, the "magnetizable metal powder" may be simply referred to as "metal powder."

[0017] <Method of manufacturing a coated metal member> The method for producing a coated metal member according to the present disclosure includes: A first step of magnetizing at least one of a magnetizable metal member and a paint containing magnetizable metal powder; a second step of applying the paint containing the metal powder to the surface of the metal member by magnetic force; A third step of hardening the paint containing the metal powder attached to the surface of the metal member; Includes. The method for producing a coated metal member of the present disclosure may also include an optional fourth step of demagnetizing the magnetized metal member. Here, "magnetizable" means "the property of becoming magnetic when a magnetic field is applied to a magnetizable metal member or metal powder, such that paint containing metal powder adheres to the surface of the metal member due to magnetic force."

[0018] The method for producing a coated metal member according to the present disclosure includes the above steps, and thus can provide a method for producing a coated metal member that can produce a coated metal member in a small space and with low equipment costs, for the following reasons.

[0019] Conventionally, a method for producing a coated metal member for the purpose of rust prevention or for imparting design has required a large spray device or immersion tank. Specifically, a coating booth, an air conditioner, an electrodeposition device, a paint circulation device, a drying oven, and a conveying device are required as "coating facilities," while a spray gun, an airless coating machine, an electrostatic coating machine, and the like are separately required as "coating equipment." However, the method for producing a coated metal member of the present disclosure does not require such a requirement, since the coating material is simply attached to the metal member to be coated by magnetic force. This contributes to space saving and low equipment costs.

[0020] As described above, the method disclosed herein can provide a method for producing a coated metal component, which can produce a coated metal component in a small space and at low equipment costs.

[0021] In addition, in the method of the present disclosure, the paint itself is attracted to the surface of the metal component by magnetic force, making it easier to obtain a coated metal component that has a thick film and is resistant to sagging. Furthermore, the method of the present disclosure makes it possible to adjust the magnetic susceptibility when magnetizing a metal member and / or a paint containing metal powder, which makes it easy to control the film thickness of the coated metal member. Furthermore, the method of the present disclosure can transport metal members by magnetic force, thereby making it possible to prevent hanger marks. Additionally, the method of the present disclosure utilizes magnetic force to suspend metal members by their ends, thereby preventing hanger marks. Furthermore, if the ends of the metal parts are covered with caps, there will be no hanger marks and touch-up painting will be unnecessary.

[0022] Hereinafter, the method for producing a coated metal member according to the present disclosure will be described in detail.

[0023] <1st process> In the first step, at least one of a magnetizable metal member and a paint containing magnetizable metal powder is magnetized (see FIG. 1(a)).

[0024] (Magnetizable metal parts) Examples of the magnetizable metal member include a metal member containing a ferromagnetic material, a metal member containing a rare earth metal, etc. Examples of the ferromagnetic material include iron, cobalt, nickel, and alloys thereof. Examples of the rare earth metal include neodymium, samarium, etc. By including these elements, smooth magnetization becomes possible.

[0025] The shape of the metal member is not particularly limited as long as it is magnetizable and a coated metal member can be obtained. Examples of the shape include a coil shape, a columnar shape, a prismatic shape, a cylindrical shape, and a square tube shape. Specific examples of metal parts include spring parts, square steel and H-shaped steel used for building pillars and beams, display stands, racks and other fixtures used in stores, and road materials such as guardrails and poles.

[0026] The metal member may be a chemically treated metal member having a coating of a phosphate such as zinc phosphate or iron phosphate on the surface thereof, so long as it is magnetizable and a coated metal member can be obtained.

[0027] The metal member may have a suspension portion at its end for transportation, and may have a perforated portion at its center for passing a rotating shaft (axis) for rotational drive (not shown in FIG. 1).

[0028] (Paint containing magnetizable metal powder) The paint containing magnetizable metal powder may be, for example, a powder paint containing a binder and magnetizable metal powder. The powder paint may contain other additives.

[0029] Each component will be described below. In addition, magnetizable metal powder is also referred to as "metal powder", and paint containing magnetizable metal powder is also referred to as "paint".

[0030] -binder- The binder may be either an organic binder (hereinafter also referred to as "binder resin") or an inorganic binder. The binder may be a hybrid binder containing a binder resin and an inorganic binder. Examples of the binder resin include thermosetting resins such as epoxy resins, phenolic resins, amino resins, unsaturated polyesters, and thermosetting elastomers; and thermoplastic resins such as acrylic resins, polyesters, vinyl chloride resins, styrene resins, styrene-based thermoplastic elastomers, and thermoplastic elastomers (e.g., olefin-based thermoplastic elastomers). The binder resins may be used alone or in combination of two or more. Examples of the inorganic binder include aluminum oxide, aluminum alkoxide, boric acid, metaboric acid, tetraboric acid, borates, metaborates, tetraborates, water-soluble zirconium compounds, and water-soluble titanium compounds. Examples of inorganic binders include cement, gypsum, and water glass.

[0031] -Metal powder- Examples of the metal powder include metal powder made of a ferromagnetic material, metal powder made of a rare earth metal, etc. Examples of the metal powder made of a ferromagnetic material include ferromagnetic metal powder such as iron powder, nickel powder, and cobalt powder, and ferromagnetic metal oxide powder such as ferrite powder, triiron tetroxide powder, and γ-diiron trioxide powder. Examples of the metal powder made of a rare earth metal include neodymium powder and samarium powder. The use of these metal powders enables smooth magnetization. The metal powder may be used alone or in combination of two or more kinds. Among them, triiron tetroxide powder is preferred because it has excellent magnetizability and also serves as a black pigment.

[0032] . The shape of the metal powder is not particularly limited, and may be, for example, any shape such as a sphere, a rice grain, a needle, a brick, or a plate.

[0033] The average particle size of the metal powder is preferably 5 μm or more and 100 μm or less, more preferably 15 μm or more and 60 μm or less, and even more preferably 25 μm or more and 50 μm or less, from the viewpoint of allowing the paint to adhere to the surface of the metal component by magnetic force and forming a smooth coating. The average particle size of the metal powder can be measured using a particle size measuring device such as a laser diffraction / scattering type particle size distribution measuring device (Microtrac, manufactured by Nikkiso Co., Ltd.), and is the particle size (D50) that is the cumulative 50% particle size from the small particle size side in the volume-based cumulative particle size distribution obtained by measurement.

[0034] -Other additives- Examples of other additives include pigments, curing agents, light stabilizers, ultraviolet absorbers, surfactants, surface conditioners, and thixotropic agents.

[0035] The pigment may include a coloring pigment. In addition to the coloring pigment, the pigment may also include a glittering pigment, an extender pigment, and the like.

[0036] Examples of coloring pigments include black pigments such as carbon black and triiron tetroxide; white pigments such as titanium dioxide and zinc oxide; red pigments such as red iron oxide, cadmium red, and permanent red 2B; blue pigments such as iron blue, ultramarine blue, and copper phthalocyanine blue; yellow pigments such as yellow lead, ferric oxide hydroxide, and isoindolinone yellow; and green pigments such as chromium oxide and malachite green.

[0037] Luster pigments include aluminum flakes, bronze powder, and the like.

[0038] Examples of extender pigments include silica, mica, talc, kaolin, calcium carbonate, barium sulfate, etc.

[0039] Examples of the curing agent include phenol curing agents, amine curing agents, acid anhydride curing agents, polymercaptan curing agents, polyaminoamide curing agents, isocyanate curing agents, and blocked isocyanate curing agents. When the coating material containing metal powder contains a curing agent, a three-dimensional crosslinked structure is formed in the coating film in the curing process described below, and as a result, a coating film having sufficient coating strength is easily obtained. The curing agent can be appropriately selected depending on the type and purpose of the binder resin contained in the coating material.

[0040] Examples of the light stabilizer include derivatives of benzophenone, benzotriazole, dithiocarbamate, and tetramethylpiperidine.

[0041] Examples of the ultraviolet absorbing agent include a benzotriazole-based ultraviolet absorbing agent, a benzophenone-based ultraviolet absorbing agent, a benzoate-based ultraviolet absorbing agent, and a hydroxyphenyltriazine-based ultraviolet absorbing agent.

[0042] Examples of the surfactant include cationic surfactants, anionic surfactants, and nonionic surfactants. Examples of cationic surfactants include quaternary ammonium salts and alkylamine salts. Examples of the anionic surfactant include carboxylates, sulfonate salts, sulfate esters, and phosphate esters. Examples of the nonionic surfactant include acetylene glycol surfactants, ethylene glycol-added acetylene glycol surfactants, and silicone dispersants.

[0043] Examples of the surface conditioner include silicones such as dimethyl silicone and methylphenyl silicone, and acrylic oligomers.

[0044] Examples of the thixotropic agent include fine powder of silicic acid, pumice, calcium carbonate, and zeolite.

[0045] -Paint type- From the viewpoint of adhering to the surface of the metal member by magnetic force and forming a coating, the coating material is preferably particles having a core-shell structure having a core and a shell layer covering at least a part of the core. It is preferable that the particles having a core-shell structure have a metal powder in the core and a binder in the shell layer, and further, other additives are preferably contained in the shell layer. When the paint is made of particles having a core-shell structure, the paint can be easily attached to the surface of the metal member by magnetic force, and a coating can be easily formed on the surface of the metal member. Also, when the paint containing metal powder is made of particles having a core-shell structure, the paint itself is attracted to the surface of the metal member by magnetic force, so that a coating having a thick film and an anti-sagging effect can be easily obtained.

[0046] Methods for forming particles having a core-shell structure include an immersion method in which a core material is immersed in a solution for forming a shell layer, a spray method in which a solution for forming a shell layer is sprayed on the surface of a core material, a fluidized bed method in which a solution for forming a shell layer is sprayed on a core material suspended in flowing air, etc. The core-shell structure can be confirmed by a transmission electron microscope (TEM), a scanning transmission electron microscope (STEM), etc.

[0047] The average particle size of the paint (i.e., the average particle size of the powder paint) is preferably 10 μm or more and 105 μm or less, more preferably 20 μm or more and 65 μm or less, and even more preferably 30 μm or more and 55 μm or less, from the viewpoint of adhering to the surface of the metal component by magnetic force and forming a coating. The average particle size of the paint can be measured using a laser diffraction / scattering particle size distribution analyzer (Microtrac, manufactured by Nikkiso Co., Ltd.). In the cumulative particle size distribution based on volume obtained by the measurement, the particle size that is 50% cumulative from the small particle size side (D 50 ).

[0048] The paint is not limited to powder paint, but may be liquid paint. The liquid paint contains a solvent in addition to the above components. Examples of the solvent include ester-based organic solvents such as 3-methoxybutyl acetate, ethyl acetate, isopropyl acetate, and butyl acetate; ketone-based organic solvents such as methyl ethyl ketone, acetone, methyl isobutyl ketone, cyclohexanone, and isophorone; Solvesso 100 (Exxon Mobil Corp.), Solvesso 150 (Exxon Mobil Corp.); and water. The solvent may be used alone or in combination of two or more. The liquid paint preferably contains a surfactant. When the liquid paint contains a surfactant, the dispersion of the binder, metal powder, and other additives (pigments, etc.) in the liquid paint is improved, and the liquid paint can adhere to the surface of the metal member as a magnetic fluid.

[0049] -Content of each ingredient- The content of the binder is, for example, 20% by mass or more and 90% by mass or less with respect to 100% by mass of the total mass of the paint.

[0050] The content of the metal powder is, for example, 5% by mass or more and 30% by mass or less with respect to the total mass of the paint (100% by mass).

[0051] The content of the other additives is, for example, 0.5% by mass or more and 5% by mass or less with respect to 100% by mass of the total mass of the paint including the metal powder.

[0052] The content of the solvent is, for example, from 0% by mass to 5% by mass, relative to 100% by mass of the total mass of the paint.

[0053] When the paint is a liquid paint, the solid content concentration of the paint is, for example, 20% by mass or more and 95% by mass or less with respect to the total mass of the paint being 100% by mass.

[0054] The coating material containing the metal powder can be prepared by known methods.

[0055] -Magnetized- The magnetization is performed on at least one of a magnetizable metal member and a paint containing magnetizable metal powder.

[0056] When magnetizing a magnetizable metal member, the magnetization method is not particularly limited as long as a coated metal member can be obtained. The magnetization method may be a method for forming a thickness direction, two poles on one side, four poles on both sides, multiple poles on one side, multiple poles on both sides, a radial direction, two poles inside and outside, or a vertical direction, etc.

[0057] When magnetizing a metal member, the magnetization is performed by applying a magnetic field with a magnetic flux density equal to or higher than the magnetic flux density at which the metal member can hold the weight of the paint containing metal powder. By performing magnetization within the above range, the paint containing metal powder can be easily attached to the surface of the metal member by the magnetic force, and a coated metal member can be easily obtained. On the other hand, by adjusting the magnetic flux density, the orientation of paint particles due to the magnetic force on the surface of the metal member can also be suppressed. The magnetic flux density can be measured using a Gauss-Meter. In addition, by adjusting the magnetic susceptibility, it can also be made easier to control the film thickness of the coated metal member.

[0058] When magnetizing the metal powder in the paint, the direction of the applied magnetic field is not particularly limited as long as a coated metal member is obtained. The direction of the applied magnetic field may be, for example, a direction that forms an angle of 0° or more and ±180° or less with respect to an axis perpendicular to the surface on which the paint matrix is ​​arranged.

[0059] When magnetizing the metal powder in the paint, the magnetization is performed by applying a magnetic field with a magnetic flux density equal to or higher than the magnetic flux density at which the metal member can hold the weight of the paint containing the metal powder. By performing magnetization within the above range, the magnetic force makes it easier for the paint to adhere to the surface of the metal member, and it is easier to obtain a coated metal member. On the other hand, by adjusting the magnetic flux density, it is possible to suppress the orientation of the paint particles on the surface of the metal member due to the magnetic force. The magnetic flux density can be measured with a Gauss-Meter. In addition, by adjusting the magnetic susceptibility, it can also be easier to control the film thickness of the coated metal member.

[0060] The magnetization can be performed using a known magnetizing means including an air-core coil or a magnetizing yoke and a magnetizing power source.

[0061] <Second process> In the second step, a paint containing metal powder is attached to the surface of the metal component by magnetic force (see FIG. 1(b)).

[0062] -Attachment- In the second step, the adhesion may be a process of adhering a paint containing non-magnetized metal powder to a magnetized metal member by magnetic force, or a process of adhering a paint containing magnetized metal powder to a non-magnetized metal member by magnetic force. Also, the adhesion may be a process of adhering a magnetized metal member and a paint containing magnetized metal powder by magnetic force.

[0063] The metal member and the paint are attached by magnetic force. The attachment method is not particularly limited as long as it is by magnetic force, and for example, the metal member may be placed on the paint matrix and attached, or may be attached while being transported by a transport means. The attachment may be performed at room temperature (25°C), or may be performed after the metal member is preheated in advance. In this case, the preheating temperature is, for example, 40°C or higher and 230°C or lower.

[0064] -rotate- The second step may further include a step of rotating the metal member. In this case, the metal member may rotate around a rotating shaft (axis) passing through a perforated portion provided in the center of the metal member (see FIG. 1(b). The rotating shaft is not shown). The rotation may be forward rotation or backward rotation. By applying the paint to the metal member while rotating, it becomes easier to obtain a coated metal member with a uniform coating thickness.

[0065] <3rd process> In the third step, the paint containing the metal powder attached to the surface of the metal component is cured (see FIG. 1(c)). By curing, a coated metal component consisting of a continuous film of the paint containing the metal powder can be obtained.

[0066] -Curing- The curing method is not particularly limited. The coating material may be cured by drying at room temperature or by baking.

[0067] When the composition is cured by drying at room temperature, the composition may be naturally dried or dried under reduced pressure.

[0068] When curing is performed by baking, the baking method is not particularly limited, and the baking can be performed by using known means such as an electric furnace, a hot air heater, an infrared heater, a far-infrared heater, and high-frequency heating.

[0069] The baking temperature is, for example, from 80° C. to 230° C. When the baking temperature is within the above range, a coated metal member having sufficient coating strength and free of cracks or the like can be easily obtained.

[0070] The baking time is, for example, from 5 minutes to 30 minutes. By keeping the baking time within the above range, it becomes easier to obtain a coated metal member that has sufficient coating strength and is free of cracks.

[0071] -4th process- The fourth step is to demagnetize the magnetized metal member. Demagnetizing the coated metal member can prevent ferromagnetic materials such as iron from adhering to the coated metal member when it is in use. Demagnetizing also makes it possible to remove machining powder adhering to the surface of the coated metal member. The method of the present disclosure can also transport the coated metal member by magnetic force without demagnetizing it, in which case hanger marks can be prevented.

[0072] The demagnetization can be performed using a known demagnetization means including a demagnetization coil and a demagnetization power supply. The demagnetization may be resonance damping demagnetization, thermal demagnetization, or AC demagnetization, and may be appropriately selected from those optimized through experiments.

[0073] According to the method described above, a coated metal member can be produced in a small space and at low equipment costs.

[0074] In the method for producing a coated metal member of the present disclosure, for example, it is preferable to obtain a coated metal member having a metal member and a coating provided on the surface of the metal member and containing 5 to 30 mass % metal powder. If the metal powder content of the coating is 5 mass % or more, sagging of the coating is suppressed when the coating is formed using magnetic force. On the other hand, if the metal powder content of the coating is 30 mass % or less, the coating exhibits a sufficient protective function. [Explanation of symbols]

[0075] 10. Magnetizable metal parts 20 Paint containing magnetizable metal powder 30 Coated metal parts

Claims

1. A first step of magnetizing at least one of a magnetizable metal member and a paint containing magnetizable metal powder; a second step of applying the paint containing the metal powder to the surface of the metal member by magnetic force; a third step of curing the paint containing the metal powder adhered to the surface of the metal member; A method for producing a coated metal member, comprising:

2. The method for producing a coated metal member according to claim 1 , further comprising the step of demagnetizing the metal member after the third step.

3. The method for producing a coated metal member according to claim 1 , wherein the second step further comprises a step of rotating the metal member.

4. The method for producing a coated metal member according to claim 1 , wherein the metal powder is triiron tetroxide powder.

5. A metal member; A coating provided on a surface of the metal member and containing 5 to 30 mass % of metal powder; A coated metal member having the above structure.

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