JP2010131604A - Metallic component and method for forming the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for forming a metallic component having a glassy coating layer of high-hardness on the surface thereof. <P>SOLUTION: Onto a color coat layer 2 formed on the surface of a flat metallic plate 1, a polysilazane solution or, a low-temperature curable polysilazane solution added with a catalyst such as palladium or amine, or an alkoxy metal-salt solution containing SiO<SB>2</SB>as a main ingredient is applied. Then, the solution is baked at a temperature of 150-300°C, so that a glassy coating layer 3 with a thickness of 0.4-10 μm is formed. The metallic plate, on which the glassy coating layer 3 is provided, is formed by drawing or bending. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a metal part having a glassy coating layer formed on its surface and a method for forming the metal part.

  Conventionally, a coating is formed on the surface of a metal part for the purpose of antifouling and preventing scratches. Such metal parts usually have a glassy coating layer formed on the surface, and when drawn or bent to a product shape, the glassy coating layer peels off or cracks during molding. After forming into a product shape, a glassy coating layer is formed on the surface by a sol-gel method or the like.

  However, when a glassy coating layer is formed after molding, in the case of a complex shape product, a part where the glassy coating layer is not formed particularly in the corner portion or the like is formed, or it is formed abnormally thicker than other parts. Some parts may occur.

Then, the technique disclosed by patent documents 1-3 is known as a glassy coating layer which can be bent after forming a glassy coating layer.
In Patent Document 1, a functional carrier such as a dye or a pigment is mixed with a composition in which the weight ratio of hydrolyzable silane and organosilane is 5 to 50:50 to 95, and this is coated on a support. However, it is disclosed that the glassy layer is formed by densification by heat.
In US Pat. No. 6,057,089, a coating composition obtained from hydrolyzable silane and oligomeric nanoscale SiO ₂ particles derived therefrom and / or alkali and alkaline earth metal oxides and hydroxides on a metal surface. It is disclosed that a glassy layer is formed by applying and densifying with heat.
In Patent Document 3, an alkali metal silicate-containing coating sol is applied to a support, and this coating film is heated in a first stage either in an oxygen-containing atmosphere or under reduced pressure with a residual pressure of 15 mbar or less, It is disclosed that a glassy coating having a sufficient density and deformable can be obtained by heating in the second stage in a low oxygen atmosphere.
In Patent Document 4, a water glass cured body film is formed on the surface of a substrate such as a metal, and an aluminum sulfate aqueous solution is brought into contact with the film and subjected to heat treatment to produce aluminum silicate on the surface portion of the water glass cured body film. Is disclosed.
JP-T 9-504768 JP-T-2001-518979 Special Table 2007-521984 JP 2008-120918 A

  In Patent Documents 1 to 3 described above, a pigment (dye) is mixed in the coating liquid as a coloring means. However, when a pigment is added, pinholes are formed by the pigment particles, resulting in poor corrosion resistance (salt spray) due to the pinholes.

  In Patent Document 4, the coating liquid is aqueous, and the thickness of the coating film to be formed cannot be increased. If the thickness is thin, if the film is formed and then formed by drawing or bending, the elongation is reduced. The film peels off at the part where it was damaged.

In order to solve the above problems, a metal part according to the present invention has a low temperature cured polysilazane solution or an alkoxy metal salt in which a color coat layer is formed on the surface, and a catalyst such as polysilazane, palladium or amine is added to the outside of the color coat layer. A glassy coating color coated metal plate having a surface hardness of a material having a glassy coating layer formed thereon and having a pencil hardness of H7 or more is formed by drawing or bending.
In addition, when polysilazane is used as the glassy coating layer, a water-soluble metal salt solution may be further coated thereon to impart hydrophilicity. Examples of the water-soluble metal salt solution include MS90 or SS900 manufactured by Nippon Sheet Laboratory.
In order to solve the above problems, the metal part molding method according to the present invention is premised on a metal plate having a color coat layer on the surface. Then, a polysilazane solution or a low-temperature cured polysilazane solution to which a catalyst such as palladium or amine is added or an alkoxy metal salt solution mainly composed of SiO ₂ is applied on the color coat layer of the metal plate, and a temperature of 150 ° C. to 300 ° C. To form a glassy coating layer having a thickness of 0.4 μm to 10 μm, and the metal plate on which the glassy coating layer is formed is drawn or bent.
The reason why the firing temperature is set to 150 ° C. to 300 ° C. is that if it is less than 150 ° C., it cannot be converted into SiO ₂ sufficiently and high hardness characteristics cannot be obtained. This is because the surface of the quality coating layer is easily damaged, and when the temperature exceeds 300 ° C., the lower color coating layer is likely to be discolored. Also, the thickness of 0.4 μm to 10 μm is because the glass coating layer cannot be obtained due to the influence of the surface hardness of the underlying metal material because the lath coating layer is thin below 0.4 μm. When forming or bending after forming the coating layer, the surface of the glassy coating layer is easily damaged, and when the thickness is 10 μm or more, the glassy coating layer is formed when drawing or bending after forming the glassy coating layer. This is because cracks are easily generated and peeling is likely to occur.

According to the present invention, even if drawing or bending is performed after forming a glassy coating layer on the surface of a metal part, the glassy coating layer is not scratched, cracked, or peeled off.
Since the vitreous coating layer is formed before the drawing or bending, the vitreous coating layer can be formed at a location where the thickness of the vitreous coating layer is constant and cannot be applied after molding.

  Further, since the firing is performed at a low temperature, the lower color coat layer is not discolored (oxidized) by heat.

Embodiments of the present invention will be described below with reference to the accompanying drawings. 1 is a side view of a metal plate before forming, FIG. 2 is an enlarged cross-sectional view of a surface layer portion of the metal plate, FIG. 3A is a plan view of a cover of a mobile phone as an example of a metal part after forming, (b) is a B direction arrow figure of (a), (c) is a C direction arrow figure of (a).

  A color coat layer 2 is formed on the surface of the flat metal plate 1 before forming, and a glassy coating layer 3 is formed on the color coat layer 2. The metal plate 1 may be titanium, aluminum, magnesium alloy or the like in addition to stainless steel. The color coat layer 2 may also be formed on the back surface of the metal plate 1.

  The color coat layer 2 is formed with a thickness of 100 to 10000 nm, and the color coat layer 2 is a colored glass layer formed by spray coating baking using organic / inorganic hybrid silicon such as modified polyester silicon as a main raw material, Cr layer or Ni layer formed by electrolytic plating, Ni layer formed by electroless plating, aluminum oxide layer formed by anodic oxidation, magnesium oxide layer, titanium oxide layer, or inco method, ion plating method, PVD And various layers formed by sputtering and sputtering.

In addition, in order to color the aluminum oxide layer (alumite treatment) or the magnesium oxide layer formed by anodization, a pigment (dye) is impregnated.
The glassy coating layer 3 is formed to a thickness of 0.4 μm to 10 μm, preferably 1 to 2 μm. The glassy coating layer 3 is coated with a polysilazane solution and heated at a temperature of 250 ° C. to 300 ° C. or less. It is obtained by. The coating thickness per one time of the polysilazane solution is 2 μm, and when coating more than that, it can be obtained by recoating.
The reaction formula is as follows.

(SiH ₂ NH) + 2H ₂ O → SiO ₂ + NH ₃ + 2H ₂
Further, instead of the polysilazane solution, an alkoxy metal salt solution (manufactured by Nippon Sheet Laboratory Co., Ltd., product number G-90) containing SiO ₂ as a main component may be applied.
Moreover, since the lower color coat layer 2 and the base material 1 are discolored when converted to a silica thin film at a high temperature, the firing temperature is preferably as low as possible. For this purpose, by adding a catalyst such as palladium or amine to the polysilazane solution, the calcination temperature can be greatly lowered to about 250 ° C. or less and about 150 ° C.
The flat metal plate 1 on which the color coat layer 2 and the glassy coating layer 3 are formed by the above-described steps is subjected to drawing and punching, so that the window portion 4 and the peripheral curl portion 5 are formed as shown in FIG. The cover 6 for a cellular phone in which is integrally formed is obtained.
The vitreous coating layer formed by the method according to the present invention has high peel resistance, and no cracking or peeling occurs even in a corner portion where tensile force or compressive force acts by press molding or punching molding. Therefore, in addition to the cover of the mobile phone, for example, when used for a case of a household electric appliance, a glassy coating layer can be formed before molding, so that the production process is greatly improved.

Side view of a flat metal plate before being formed by the method according to the present invention Expanded sectional view of the surface layer of the metal plate (A) is a plan view of a cover of a mobile phone as an example of a metal part according to the present invention (b) is a B direction arrow view of (a) (c) is a C direction arrow view of (a)

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Flat metal plate, 2 ... Color coat layer, 3 ... Glassy coating layer, 4 ... Window part, 5 ... Curl part of a periphery, 6 ... Cover of a mobile telephone.

Claims (2)

A surface on which a color coat layer is formed on the surface of the metal plate, and a glassy coating layer made of a low-temperature curing polysilazane solution or an alkoxy metal salt with a catalyst such as polysilazane or palladium or amine added on the outside of the color coat layer A metal part obtained by drawing or bending a glass-coated color-coated metal plate having a pencil hardness of H7 or higher. A color coat layer is formed on the surface of the metal plate, and a polysilazane solution or a low-temperature curing polysilazane solution to which a catalyst such as palladium or amine is added or an alkoxy metal salt solution mainly composed of SiO ₂ is applied on the color coat layer. , Firing at a temperature of 150 ° C. to 300 ° C. to form a glassy coating layer having a thickness of 0.4 μm to 10 μm, and drawing or bending the metal plate on which the glassy coating layer is formed. To mold metal parts.