JP2005199216A - Bright light alloy-made part - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a bright light alloy-made part which has a clearly developed color area and a bright area excellent in brightness and on which the occurrence of corrosion such as filiform corrosion is effectively prevented and which has excellent durability. <P>SOLUTION: The bright light alloy-made part 1 is provided with a casting 2 obtained by casting a light alloy and has the color area 7 composed of at least one color and the bright area 8 having brightness on the surface of the casting. The color area 7 is composed of a first coating film 3 arranged to cover at least a part of the surface of the casting 2. The bright area 8 is composed of a second coating film 4 which has brightness and is arranged to cover at least a part of the first coating film 3 constituting the color area 7. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a bright light alloy part. More specifically, the present invention relates to a bright light alloy part that has a vivid colored region and an excellent glitter region, is effectively prevented from corrosion such as thread rust, and has excellent durability.

  Cast articles made by casting a light alloy containing aluminum, magnesium, and the like are light in weight, and thus demand is increasing in various fields. For example, conventionally, steel wheels have been mainly made of steel. However, since automobiles are required to improve fuel efficiency due to the upgrading of automobiles or global warming problems, castings made of light alloys are required. Widely used.

  In parts such as wheels using light alloy castings, the surface of the castings has a predetermined color in order to improve its design or durability. A film is formed. Usually, film formation on the surface of a cast product is performed by, for example, cutting or polishing a cast product surface (for example, casting surface) or an excess portion using a cutting tool or the like, and then cutting or polishing the cast product. It is performed by forming a coating film on the surface of the film.

  In particular, when a light alloy cast product is used as a wheel, various attempts have been made on its design surface. For example, the surface of the cast product is coated by performing an electric field coloring alumite treatment, and then cut. A manufacturing method of a bright aluminum road wheel (hereinafter also referred to as a wheel) in which a part of a painted surface is cut by processing to form a bright surface is disclosed (for example, see Patent Document 1). In addition to the wheel, the method for forming the bright surface by cutting as described above is also applied to a method for manufacturing a suspension such as a shock absorber.

Further, there is disclosed a brightened aluminum part capable of obtaining an appearance having an arbitrary color depending on a viewing angle as well as having a chrome plating appearance with respect to an aluminum casting (see, for example, Patent Document 2). This brightened aluminum part includes a resin coating film having a predetermined film thickness and a metal thin film coated by a sputtering method. Specific examples thereof include automobile wheels.
Japanese Patent Laid-Open No. 7-329502 JP 2003-25495 A

  However, the wheel manufactured by the method for manufacturing a bright aluminum road wheel described in Patent Document 1 has a step formed by cutting of, for example, 100 μm or more at the boundary between the painted surface and the bright surface (cut surface). For this reason, there is a problem that cracks and the like are generated on the painted surface and yarn rust is easily generated. Moreover, in the manufacturing method described in Patent Document 1, there is a problem that the cutting process has to be performed twice before and after coating, and the manufacturing process becomes complicated.

  In addition, the brightened aluminum part described in Patent Document 2 has a problem of high cost because a metal thin film is formed by a sputtering method. Further, there is a problem that it is difficult to form a metal thin film in a portion where the distance is long or the surface is vertical.

  The present invention has been made in view of the above-described problems, and has a vivid colored colored region and an excellent glittering region, and corrosion such as yarn rust is effectively prevented and durability is improved. Providing excellent light alloy parts.

  The present invention provides the following bright light alloy parts.

[1] A bright light alloy part comprising a cast product obtained by casting a light alloy, the surface of the cast product having a colored region composed of at least one color and a bright region of glitter, The colored region is composed of a first coating film disposed so as to cover at least a part of the surface of the cast product, and the glitter region is the first coating constituting the colored region. A bright light alloy part comprising a second paint film having a glitter property so as to cover a part of the surface of the film.

[2] The first coating film constituting the colored region includes at least one resin selected from the group consisting of polyester resin, acrylic resin, epoxy resin, vinyl chloride resin, urethane resin, and aminoalkyd resin. The bright light alloy part according to [1].

[3] The bright light alloy part according to [1] or [2], wherein the second coating film constituting the bright region includes an acrylic resin.

[4] A protective layer comprising a third coating film disposed so as to cover the surface of the second coating film constituting the glitter region and the exposed surface of the first coating film. The bright light alloy part according to any one of [1] to [3].

[5] The bright light alloy part according to any one of [1] to [4], wherein a surface of the cast product at a boundary portion between the colored region and the bright region has smoothness.

[6] The bright light alloy part according to [4] or [5], wherein a level difference on the surface of the protective layer at a boundary between the colored region and the bright region is 10 μm or less.

[7] The above [1] to [6], further comprising an underlayer composed of a fourth coating film disposed between the first coating film constituting the colored region and the cast product. The bright light alloy part according to any one of the above.

  According to the present invention, there is provided a bright light alloy part that has a vivid colored colored region and an excellent glitter region, is effectively prevented from corrosion such as yarn rust, and has excellent durability. can do.

  Hereinafter, with reference to the drawings, an embodiment of a bright light alloy part of the present invention will be described in detail, but the present invention is not construed as being limited thereto, and the scope of the present invention is not limited thereto. Various changes, modifications, and improvements can be made based on the knowledge of those skilled in the art without departing from the scope.

  FIG. 1 is an enlarged cross-sectional view schematically showing a part of a cross section perpendicular to the surface in one embodiment of a bright light alloy part of the present invention. As shown in FIG. 1, a bright light alloy part 1 of the present embodiment includes a cast product 2 formed by casting a light alloy, and a colored region 7 composed of at least one color on the surface of the cast product 2. A bright light alloy part 1 having a brilliant brilliant region 8, wherein the colored region 7 is provided from the first coating 3 disposed so as to cover at least a part of the surface of the casting 2. The glitter region 8 is composed of a second coating film 4 having a glitter property disposed so as to cover a part of the surface of the first coating film 3 constituting the colored region 7. It will be. As shown in FIG. 2, conventionally, a bright light alloy part 21 having a colored region 27 arranged in a predetermined color and a bright region 28 on the surface of a cast product 22 is at least one of the surfaces. By cutting a part of the coating film 23 formed by coating the portion with a predetermined color, the original metal surface of the light alloy cast product 22 is exposed to form the glitter region 28. For example, such a conventional bright light alloy part 21 has a step of 100 μm or more on the surface corresponding to the boundary portion 29 between the colored region 27 and the bright region 28 formed by cutting the surface. As a result of this step, cracks or the like are generated in the coating film 23, and corrosion such as thread rust is generated from the cracks.

  The bright light alloy part 1 according to the present embodiment includes the first coated film 3 in which the colored region 7 is disposed so as to cover at least a part of the surface of the casting 2. Since the region 8 is composed of the second coating film 4 having a glitter property disposed so as to cover a part of the surface of the first coating film 3 constituting the colored region 7. The surface step corresponding to the boundary portion 9 can be reduced, cracks and the like hardly occur in the first and second coating films 3 and 4, and the occurrence of yarn rust and the like is effectively prevented. .

  In the bright light alloy part 1 of the present embodiment, the first coating film 3 constituting the colored region 7 is made of a polyester resin, an acrylic resin, an epoxy resin, a vinyl chloride resin, a urethane resin, and an aminoalkyd resin. It is preferable to include at least one resin selected from the group. Specifically, it is preferable that a film is formed by applying at least one kind of conventionally known solvent paint, powder paint, and water-based paint. Although not particularly limited, examples of solvent paints include polyester solvent paints and acrylic solvent paints, and examples of powder paints include epoxy powder paints, epoxy polyester hybrid powder paints, Preferred examples include polyester powder paints and acrylic powder paints. Moreover, as a water-based paint, an epoxy-type water-based paint etc. can be mentioned as a suitable example. In addition, this 1st coating film 3 may be a multilayer coating film comprised from two or more coating films.

  The thickness of the first coating film 3 is not particularly limited and is preferably 10 to 200 μm, although it varies depending on the type of paint used and the base color. Furthermore, for example, when a solvent paint is used as a paint for forming the first coating film 3, the thickness is preferably 10 to 30 μm. For example, a powder paint or a first paint film When a multi-layer coating film composed of two or more coating films is used, it is preferably 20 to 200 μm. If the thickness of the first coating film 3 is less than 10 μm, the first coating film 3 may be peeled off. If the thickness exceeds 200 μm, the thickness of the first coating film 3 becomes too thick and the cost is high. May be.

  Moreover, in the bright light alloy part 1 of this Embodiment, it is preferable that the 2nd coating film 4 which comprises the bright area | region 8 contains an acrylic resin. Specifically, the film is preferably formed by applying a solvent paint such as an acrylic solvent paint.

  The thickness of the second coating film 4 is not particularly limited and varies depending on the type of paint used and the base color, but is preferably 0.5 to 10 μm, for example. If the thickness of the second coating film 4 is less than 0.5 μm, the glitter may not be sufficiently exhibited. Moreover, when it exceeds 10 micrometers, the 2nd coating film 4 may become easy to peel. Moreover, the thickness of the second coating film 4 is relatively thin, specifically, by allowing the color of the colored region 7 to pass through by setting the thickness of the colored coating 7 to about 0.5 to 3 μm. 8 can be formed. Conversely, by setting the thickness to about 4 to 8 μm, it is possible to form the bright region 8 having a color tone that is not affected by the color of the colored region 7.

  In the case of forming such a colored region 7 and a bright region 8, first, for example, using the paint gun, the above-described first coating film 3 is made of the resulting bright light alloy on the surface of the casting 2. The colored region 7 and at least the bright region 8 in the component 1 are applied to the region where the colored region 7 is formed, and then the portion to be left as the colored region 7 is covered with masking, and the bright region 8 is formed in the portion not covered by this masking. It is realizable by apply | coating the coating film 4 of this. In the bright light alloy part 1 of the present embodiment, a region in which the first coating film 3 and the second coating film 4 are mixed in the boundary portion between the colored region 7 and the bright region 8 (hereinafter, referred to as “the bright light alloy part 1”). It may have a mixed area (sometimes referred to as not shown). For example, when the masking is provided on the portion to be left as the colored region 7 as described above, this mixed region (not shown) has a gap between the surface of the casting 2 and the second coating. When the film 4 is applied with a coating gun, the second coating film 4 can be slightly penetrated through the gap, and the first coating film 3 and the second coating film 4 can be mixed and formed. . By having such a mixed region (not shown), the plating brightness can be gradation, and the change from the colored region 7 to the bright region 8 can be continuous.

  The casting 2 used for the bright light alloy part 1 of the present embodiment is obtained by casting a light alloy, and preferably contains at least one of aluminum and magnesium as the light alloy.

  In the bright light alloy part 1 of the present embodiment, after the cast product 2 constituting the bright light alloy part 1 is machined so as to have a design shape as a final product after casting, Since it is not necessary to perform machining on the surface separately, it is preferable that the surface of the cast product 2 at the boundary portion 9 between the colored region 7 and the bright region 8 has smoothness. By comprising in this way, the adhesiveness and durability of the colored area | region 7 and the brightness area | region 8 can be improved. Note that, in the bright light alloy part 1 of the present embodiment, when the uneven portion of the design shape of the bright light alloy part 1 as the final product is included in the boundary portion between the colored region 7 and the bright region 8. As long as the surface of the casting 2 has a shape according to the irregularities of the design shape.

  Further, in the bright light alloy part 1 of the present embodiment, the bright light alloy part 1 is disposed so as to cover the surface of the second coating film 4 constituting the bright region 8 and the exposed surface of the first coating film 3. It is preferable to further have a protective layer 10 composed of the third coating film 5. Such a configuration not only prevents the first coating 3 constituting the colored region 7 and the second coating 4 constituting the bright region 8 from being peeled off or scratched, but also the boundary portion. The step of 9 is reduced and the occurrence of cracks and the like is effectively prevented. In this case, the step on the surface of the protective layer 10 at the boundary portion 9 between the colored region 7 and the bright region 8 is preferably 10 μm or less. In FIG. 1, the surface of the protective layer 10 at the boundary portion 9 between the colored region 7 and the bright region 8 is shown flat.

  It is preferable that the 3rd coating film 5 which comprises the protective layer 10 is a coating film with high transparency. The material preferably contains at least one resin selected from the group consisting of polyester resins, acrylic resins, and urethane resins. Specifically, it is preferable that a film is formed by applying at least one of a conventionally known clear solvent paint, clear powder paint, and clear aqueous paint. The clear solvent paint is not particularly limited, and examples thereof include polyester solvent paints and acrylic solvent paints, and clear powder paints include polyester powder paints and acrylic powder paints. Can be cited as a preferred example. Moreover, as a clear water-based coating material, an acrylic water-based coating material etc. can be mentioned as a suitable example. Although it does not specifically limit as thickness of the protective layer 10, It is preferable that it is 15-30 micrometers. By comprising in this way, it can be set as the protective layer 10 excellent in stain resistance and a weather resistance.

  In addition, the bright light alloy part 1 of the present embodiment is composed of the fourth coating film 6 disposed between the first coating film 3 constituting the colored region 7 and the cast product 2. It is preferable to further have an underlayer 11. This base layer 11 is mainly for the purpose of preventing rust and improving the adhesion of other coating films. For example, when the surface of the casting surface of the cast product 2 has irregularities or the like, The base layer 11 can improve the smoothness of the surface and improve the adhesion of the first coating film 3 constituting the colored region 7. In addition, by providing the base layer 11, the color of the colored region 7 becomes brighter.

  The fourth coating film 6 constituting the base layer 11 preferably contains at least one resin selected from the group consisting of polyester resins, acrylic resins, epoxy resins, vinyl chloride resins, urethane resins, and aminoalkyd resins. Specifically, it is preferable that the film is formed using the same paint as the paint for forming the first coating film 3. The thickness of the foundation layer 11 is not particularly limited, and by providing the foundation layer 11, the unevenness of the surface of the casting 2 is smoothed to some extent, thereby obtaining its effect. be able to. For example, the unevenness of the surface of the casting surface of the casting 2 is about 60 to 150 μm, and the unevenness of the surface when the casting 2 is machined is about 10 μm. It is preferable that it is -200 micrometers. When the thickness of the underlayer 11 is less than 10 μm, it may not be possible to sufficiently obtain the effect of rust prevention and adhesion improvement, and when it exceeds 200 μm, the material may be inferior in impact properties, May be easy to peel off. The fourth coating film 6 may be a multilayer coating film composed of two or more coating films.

  The bright light alloy part 1 of the present embodiment is preferably a vehicle part such as a two-wheeled vehicle or a four-wheeled vehicle, or a part for household electrical appliances, and further has a colored region 7 and a bright region 8 on its design surface. The vehicle is preferably a light alloy wheel for vehicles, and particularly preferably a light alloy wheel for two-wheeled vehicles having both surfaces as design surfaces (design surfaces). As shown in FIG. 3, when the bright light alloy part 1 is a vehicle light alloy wheel 12 (for example, a light alloy wheel for a motorcycle), the bright region 8 is a vehicle light alloy wheel. Twelve rim flange portions 13 are preferable. In the light alloy wheel 12 for a vehicle shown in FIG. 3, the surface other than the rim flange portion 13 is a colored region 7 configured by exposing the first coating film 3. Further, although not shown in the drawings, a protective film composed of the above-described third coating film may be disposed on the surfaces of the colored region 7 and the bright region 8.

  Hereinafter, a method for manufacturing the bright light alloy part of the present embodiment will be described. First, a cast product constituting a bright light alloy part is manufactured. This cast product can be cast according to a conventionally known casting method. The light alloy used for casting is preferably a conventionally known light alloy, for example, an alloy containing aluminum or magnesium. If there is a surplus part or the like in the cast product, the surplus part is cut and removed at this stage so that the final product shape is obtained.

  Next, degreasing treatment is performed on the surface of the obtained casting. The reason for performing the degreasing treatment is that if oils and fats adhere to the surface of the cast product, it becomes difficult to form a coating film and the adhesion may be impaired. The method of degreasing treatment is not particularly limited, and for example, a conventionally known method such as alkaline degreasing and cleaning can be suitably used. Specific examples include a method in which a cast product is cast in a commercially available degreasing agent at room temperature to 50 ° C. for about 1 to 5 minutes, or a method in which a commercially available degreasing agent is sprayed on the cast product.

  Next, pre-processing is performed as needed. The pretreatment is not particularly limited as long as it improves the adhesion of the paint and can protect the cast from corrosion. Examples of standard pretreatment include chromate treatment. Specifically, a method of immersing a cast product in a commercially available chromate treatment agent at room temperature to 50 ° C. for about 1 to 5 minutes can be exemplified. Some chromate treatment agents contain hexavalent chromium and fluoride, which can cause environmental pollution, so chromate (non-chromium) that does not contain hexavalent chromium ions and fluoride ions in the washing wastewater. It is more preferable to use a treatment agent.

  Next, if necessary, a fourth coating film constituting the base layer is formed so as to cover the cast product. By providing this base layer, it becomes possible not only to improve rust prevention and adhesion of other coating films, but also to form a colored region of the first coating film that will be formed later. Can be made more vivid. As a specific method, the coating material mentioned as a suitable coating material for forming the above-mentioned fourth coating film is applied to form a film. When powder coating is used for application, baking is performed at about 140 ° C. for about 20 minutes after application. Further, baking may be performed even when a paint other than the powder paint is used.

  Next, the coating material mentioned as a suitable coating material for forming the above-mentioned first coating film is applied so as to cover the cast product (when the base layer is provided, the base layer). One coating film is formed. This first coating film constitutes a colored region, and is formed to have a predetermined color according to the appearance of the bright light alloy part. In addition, when a powder paint is used at the time of application | coating, it bakes by the method similar to a 4th coating film. This baking may also be performed when a paint other than the powder paint is used.

  Next, the second coating film is formed by applying the coating materials mentioned above as suitable coating materials for forming the second coating film so as to cover a part of the surface of the first coating film. Film. This second coating film constitutes a brilliant region, and is formed on the region of the surface of the brilliant light alloy part that is desired to have brilliant properties. In addition, masking or the like is performed on a part of the surface of the first coating so that the bright region can be formed only in a predetermined region on the surface of the first coating. It is preferable to form a film. In the next step, when the third coating film is formed using the powder paint, baking is performed in the same manner as the fourth coating film.

  Next, if necessary, a third coating film constituting the protective layer is formed so as to cover the surface of the second coating film constituting the glitter region and the exposed surface of the first coating film. This third coating film can be formed by applying the coating materials mentioned above as suitable coating materials for forming the third coating film. By providing such a protective layer, the first and second coating films constituting the colored region and the bright region are protected, and peeling or the like is effectively prevented. This protective film is baked in the same manner as the fourth coating film in order to become the uppermost coating film of the coating film formed so far. However, when a paint containing a urethane resin is used, baking is not necessary. In addition, each coating film (1st coating film-4th coating film) mentioned above can be formed into a film using a coating gun, for example.

  EXAMPLES Hereinafter, although an Example demonstrates this invention concretely, this invention is not limited to a following example.

  In this example, a light alloy wheel for a motorcycle, which is a vehicle light alloy wheel 12 having a shape as shown in FIG. 3, was manufactured as a bright light alloy part. The first coating film 3 constituting the colored region 7 was formed using a black acrylic solvent paint so as to have a thickness of 20 μm on at least a part of the surface of the casting 2. The second coating film 4 constituting the glitter region 8 is made of an acrylic solvent paint having a glitter property on the surface of the first coating film 3 corresponding to the rim flange portion 13 of the light alloy wheel. The film was formed to a thickness of 5 μm. The protective layer was formed using an acrylic solvent paint, and the base layer was formed using an epoxy solvent paint. The protective layer was 20 μm thick, and the underlayer was 10 μm thick.

  A salt spray test for spraying salt water was performed on the light alloy wheel for a motorcycle according to this example obtained as described above. When the surface state of the light alloy wheel for a motorcycle according to this example was confirmed after 500 hours had elapsed, no rust was generated, and the glitter of the glitter region 8 was not lost. In addition, when a similar salt spray test was performed on a conventional light alloy wheel with a bright surface formed by cutting, rust was generated on the bright surface after 500 hours, and the glitter property of the bright surface was lost. It was. Thus, the light alloy wheel for motorcycles of this example (part 1 made of bright light alloy) was excellent in the durability of its surface (design surface). Further, in the light alloy wheel for a motorcycle according to the present embodiment, the bright region 8 is provided in a region corresponding to the rim flange portion 13 of the light alloy wheel, so that the tire disposed outside the rim flange portion 13 is provided. The brilliant region 8 became a design accent due to the chromatic effect of black, and the light alloy wheel for motorcycles was visually large and excellent in design.

  The bright light alloy part of the present invention has a vividly colored colored region and an excellent glittering region, and corrosion, such as thread rust, is effectively prevented and has excellent durability. Therefore, it can be suitably used for vehicle parts such as two-wheeled vehicles and four-wheeled vehicles, parts for household electrical appliances, etc., particularly for light alloy wheels for vehicles.

It is an expanded sectional view showing typically a part of section perpendicular to the surface in one embodiment of the bright light alloy parts of the present invention. It is an expanded sectional view showing typically a part of section perpendicular to the surface in the conventional bright light alloy parts. It is a top view which shows typically the wheel made from the light alloy for vehicles as an example of one embodiment of the components made from the bright light alloy of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Bright light alloy part, 2 ... Casting product, 3 ... 1st coating film, 4 ... 2nd coating film, 5 ... 3rd coating film, 6 ... 4th coating film, 7 ... Colored area | region, DESCRIPTION OF SYMBOLS 8 ... Bright area, 9 ... Boundary part, 10 ... Protective layer, 11 ... Underlayer, 12 ... Wheel made from light alloy for vehicles, 13 ... Rim flange part, 21 ... Parts made from bright light alloy, 22 ... Cast article, 23 ... Coating film, 27 ... colored area, 28 ... bright area, 29 ... border.

Claims (7)

A cast product formed by casting a light alloy, a bright light alloy part having a colored region composed of at least one color on the surface of the cast product and a bright region of glitter,
The colored area is composed of a first coating film disposed so as to cover at least a part of the surface of the cast product, and the bright area is the first area constituting the colored area. A bright light alloy part comprising a second paint film having a glitter property so as to cover a part of the surface of the paint film.   The said 1st coating film which comprises the said colored area | region contains at least 1 type of resin selected from the group which consists of a polyester resin, an acrylic resin, an epoxy resin, a vinyl chloride resin, a urethane resin, and an amino alkyd resin. The bright light alloy parts described in 1.   The bright light alloy part according to claim 1 or 2, wherein the second coating film constituting the bright region contains an acrylic resin.   A protective layer comprising a third coating film disposed so as to cover the surface of the second coating film constituting the glitter region and the exposed surface of the first coating film. The bright light alloy part as described in any one of 1-3.   The bright light alloy part according to any one of claims 1 to 4, wherein a surface of the cast product at a boundary portion between the colored region and the bright region has smoothness.   The bright light alloy part according to claim 4 or 5, wherein a step on the surface of the protective layer at a boundary portion between the colored region and the bright region is 10 µm or less.   The base layer comprised from the 4th coating film arrange | positioned between said 1st coating film and said cast product which comprises the said colored area | region is further described in any one of Claims 1-6. Parts made of bright light alloy.

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