JPS59364A - Preparation of aluminum decorative member - Google Patents

Abstract

PURPOSE:To obtain a member having decorative property different in hue at the corner part thereof imparted thereto, by subjecting the member made of an Al material to immersion painting in a specific paint having color tone different from that of the skin film thereof at a specific draw-up speed. CONSTITUTION:A colored anodic oxidation skin film is formed to an Al or an Al alloy material 1. In the next step, this member 1 is immersed in an org. solvent type paint with specific gravity of 0.9-1.2 and surface tension of 20- 30 dyne/cm containing 0.5-7wt% pigment having color tone different from that of said skin film and drawn up at a speed of 0.12-1.2m/min to carry out baking finish. By this method, a paint film becomes thin at the corner part 2 of the member 1 or the protruded part 3 or the surface and the under ground surface of the colored oxidation skin film layer is observed through the surface colored paint film layer. As the result, pref. contrast is obtained between the hue of the colored paint film on the flat part and the colored oxidation skin film layer at the parts 2, 3.

Description

DETAILED DESCRIPTION OF THE INVENTION Aluminum or aluminum alloy members (hereinafter simply referred to as aluminum members or aluminum members) are used to change the color of the base at some corners and/or surface convexities to the color of the surface. This paper relates to the color and contrast of the paint film and the manufacturing method of decorative parts that can be removed with twill.

Aluminum parts are lightweight, have high mechanical strength, and are excellent in workability, so they are used in a wide variety of fields, including building materials. However, although aluminum parts are colored in a variety of colors, they are Since it has a uniform color tone, it is not necessarily a decorative piece.

Conventionally, in order to obtain a specific part of the flat surface of an aluminum member that has a different color tone from other parts, first, the aluminum member is coated with an appropriate surface treatment and the specific part of the hind limb is completely shielded using an appropriate method. After applying electrolytic coloring using an appropriate method, the shielding material is removed, and if necessary, the entire surface is coated with a colorless transparent paint. For this reason, extremely complicated techniques are required to paint aluminum members that have flat surface areas with discoloration stains.

Moreover, if this method is applied to a part of the corner, the method becomes even more complicated. Therefore, these conventional techniques are not suitable for mass production and are expensive.

An object of the present invention is to provide a method for producing an aluminum decorative member in which a corner portion of the aluminum member is fully decorated with different hues.

By the way, in dip coating, the thickness of the coating film varies depending on the shape of the object to be coated due to the action of the surface tension of the coating material. That is, the coating film is thinner at some corners of the object than at flat areas. The present invention focuses on this point, and by appropriately combining the factors that determine the coating film thickness of the paint used for painting, we succeeded in developing a manufacturing method for a member that has a decorative effect that can be put to practical use. This is what I did.

At some corners, etc., the surface tension of the paint acts on each other at an angle, whereas it acts in the same plane on continuous flat surfaces, so the paint film becomes thinner. Therefore,
The theoretical coating thickness at a part of the corner (radius R) is: vW: Pulling speed crIL/8eC ρ: Paint density f/a/1 μ: Paint viscosity poise σ: Paint surface tension dyne, where: Therefore, When R is 0.03crL or less (Go<0.1
5), h″th = Qμ, the coating film becomes thinner in some corners, and R is 0.03~0°062cwL
In the case (0,15<G.<0.24), h”th=(
The coating thickness of the p corner part, which is 1 to 1.8μ, is thinner than that of the flat part, so theoretically,
It is thought that if the transparency of the coating film is adjusted appropriately, the underlying surface can be removed through the coating film. (See Toshibe Takahashi et al., Metal Surface Technology, Vol 27, A3, l 42 (1976)).

From the above, this type of "transparent" coating created by the dip coating method
The present invention takes advantage of this phenomenon in reverse and makes it possible to see the color of the base having a colored oxide film layer in transparent areas (some corners, surface convexities) in contrast to the color of the colored paint film. It is something.

The aluminum members used in the present invention are not only made of pure aluminum, but also alloys thereof, such as
It may be made of pure aluminum and an alloy containing II or two or more of silicon, magnesium, copper, nickel, zinc, chromium, lead, bismuth, iron, titanium, manganese, etc.

The present invention will be explained below.

The present invention consists of a combination of two steps: 1) surface treatment consisting of forming a colored oxide film on an aluminum member (partially aluminum profile), and 2) surface color painting. Furthermore, the purpose of the surface treatment of the aluminum member in the present invention is twofold: to improve the adhesion between the paint film and the aluminum member during color painting, and to improve the adhesion between the paint film and the aluminum member in specific parts of the aluminum member after the surface treatment. The objective is to provide a contrast in tone between the painted surface color and the painted surface color. In other words, if a suitable colored oxide film layer is ground-coated based on a predetermined color scheme and then painted using the method described in detail later, parts of the member 1 that do not belong to the continuous flat part, for example, a corner part. 2
, the underlying surface of the colored oxide film layer is removed through the surface colored coating layer at the convex portions 3 (hereinafter abbreviated as corner portions, etc.) on the surface, and the hue of the flat colored coating layer and the corner are aligned. The aluminum member can be used as a decorative member by creating a favorable contrast between the hue of the colored oxide film layer and the underlying color of the aluminum member.

First, we will explain the base treatment method for forming a colored oxide film on aluminum members, which has an important meaning in the present invention.
There are methods for producing colored anodic oxide films and methods for dyeing anodic oxide films.

The following methods are available for producing a colored anodic oxide film. That is, a DC voltage is applied as a mixed #Rt-electrolyte of an organic acid such as oxalic acid malonic acid, an aromatic sulfonic acid such as sulfosalicyl & m-cresol sulfonic acid, oxalic acid-sulfuric acid, sulfosalicylic acid-sulfuric acid, etc. Alternatively, pulse electrolysis is performed using an aqueous sulfuric acid solution, a mixed acid aqueous solution of oxalic acid and sulfuric acid as an electrolytic bath, or an anodic oxide film is formed on an aluminum member in an aqueous metal salt solution with an AC waveform or a DC polarity conversion waveform. , a method of electrolyzing with a pulse polarity conversion waveform to produce a colored oxide film with a color tone unique to metal salts, and secondary electrolytic coloring, such as the Asada method.

Next, as a method for dyeing an aluminum member having an anodized film, for example, commonly used organic dyes such as Congo red, rosewood, alizarin, etc., or for example, ferric ammonium oxalate, ferric potassium oxalate, permanganate, etc. There is a method using an inorganic dye such as a mixture of potassium and cobalt acetate. In addition, as a method of anodizing film treatment, an aqueous solution of sulfuric acid, chromic acid, phosphoric acid, phosphoric acid, etc. is used as an electrolytic solution. Note that anodization also contributes to fast dyeing, corrosion resistance of aluminum parts, and adhesion of surface colored coatings.

Through the coloring base adjustment method described above, the color tones observed in some corners of aluminum parts through the colored coating film include a wide range of color tones, and therefore products with a rich variety of contrast can be obtained. It can be grown. .

Next, the more important coloring coating that influences the effects of the present invention will be described. Generally, in a painted article, the degree to which the underlying surface condition of the colored oxide film layer can be observed through the upper colored coating layer is determined by the light transmittance of the upper colored coating layer and the light transmittance of the underlying surface. Determined by reflectance.

First, the transparency of the colored coating layer obtained by painting on the surface is
It is proportional to the transparency of the paint used. However, in Kempo, the surface coating is done using so-called color paints, so the factor that determines the transparency of the paint is the transparency of the pigments contained in the paint. Originally, the transparency of an object is related to the object's light reflectance and refractive index, but in martial arts, pigments with a small refractive index are desirable. As a result of examining a large number of pigments from the above point of view, the following pigments were found to have achieved good results in illegal practice.

Red Watching V Rad Permanent Carmine FB Quinacridone Hood Yellow Irgazine Yellow Product Name Ciba Geigy Benzidine Yellow Permanent Yellow (Azo Pigment) Brown Transparent Red Red Color Blue 7 Talocyanine Blue Indan Stremburu: Green Phthalocyanine Green Green Gold Purple type First Violet Dioxazine Violet Black type Carbon black Acetylene black The transparency of the colored coating on the surface is controlled by the refractive index of the pigment itself used in the paint, but of course the concentration of the pigment in the paint is also important. Ruru. Generally, in the case of color painting, 15~
It is carried out in a paint bath containing 30% by weight of pigment, but in martial arts the concentration of pigment must be reduced from the above value. In other words, when practicing Kempo, the pigment concentration should be 0.5~
It is necessary to maintain the content at 7% by weight, but preferably 0.5-3% by weight. In addition, if it is -0, 5% or less, the shading power of the coating film will be insufficient, although it is related to the coating thickness, and the purpose of colored coating will not be achieved. Furthermore, if the concentration is 7% by weight or more, the transparency of the coating film at some corners and the like is low, so the effectiveness of this method is diminished. The pigments used may be used alone or in combination of two or more. In addition, in the case of carbon-based black pigment, the pigment concentration ijO, 5 to 1.5 wt%
is preferred.

In dip coating, the coating thickness is proportional to the viscosity of the paint and the pulling rate, which is clear from the formula for the theoretical coating thickness, and is inversely proportional to the surface tension of the paint and the density of the paint. Therefore, coating pAJ in some corners etc. In order to reduce the thickness of 3L, it is necessary to use a paint with relatively high surface tension.

Therefore, it is necessary that the surface tension of the organic solvent-based paint used in the method of the present application is 20 to 30 dyneAm. If a paint has a surface tension below the lower limit of this range, 20 dyne/cm, the resulting paint film will not have the characteristics of this method, such as in parts of Lucona where it is thick. Also, 30 dyne
If it is 7 cm or more, a so-called cissing phenomenon occurs.

Further, regarding the viscosity of the paint, it is preferable that the viscosity of Ford Cup 4 is 20 to 40 seconds; if the viscosity is less than 20 seconds, the paint film will be extremely thin and will not be of practical use. If it is for 40 seconds or more, sagging occurs and the film thickness becomes non-uniform. Regarding the specific gravity of paint,
A value of 0.8 to 0.95 is appropriate.

The temperature of the paint bath varies depending on the type of organic solvent used, but is preferably 20 to 30°C. If the temperature is below 20°C or above 30°C, the surface tension of the paint and the viscosity of the paint will be outside the appropriate value range, making it difficult to obtain good results.

Moreover, the pulling speed Fio is 12 to 1.2 m/min.
is unreasonable. If it is less than 0.12 m/min, the film thickness will be too small, and if it is more than 1.2 m/min, sagging will occur and the coating will be non-uniform.

In addition, if an atmosphere containing a particularly large amount of organic solvent vapor is generated during 1-pulling, such as with a paint using a t-solvent such as trichlorethylene, and it is desired to recover the solvent by cooling this, a paint bath is used. There is no problem even if the temperature is raised to 80°C.

Next, regarding the adhesion of the coating film, as mentioned above, in this method, a boehmite film or anodic oxide film is formed as a base treatment for the aluminum material, but the boehmite film M
Since this produces a dense, fine, non-porous serrated layer on the surface of the aluminum member, paint particles are firmly adsorbed to this surface, forming a coating film with good adhesion.

Further, when anodizing is performed, a pore layer of At203 is formed on the surface of the aluminum member through a barrier layer, and the paint is carried within the pores, so that a coating M with excellent adhesion can be obtained.

Therefore, according to the present invention, 1) there is a highlight of aluminum with a good color contrast in the corner part and the surface convex part (Lr1) with extremely high decorativeness, and the corrosion resistance is also excellent.

All aluminum parts with a colored oxide film 1 are dip coated using an acrylic paint made entirely of trichlorethylene and containing a pigment different in color from the color of the oxide film, and the flat parts of this part are coated with the above paint. A decorative aluminum member with good color contrast was obtained in which the colored oxide film surface could be traced through the thin opaque colored coating film at some corners and the like.

As explained in detail above, the present invention applies dip coating using a colored organic solvent-based paint to an aluminum or aluminum alloy member having a colored anodic oxide film layer to form a uniform colored film with good adhesion. Decorative aluminum can be formed and the underlying surface can be removed through the colored surface coating layer at parts that do not belong to the continuous flat surface of the object to be coated, such as corner parts or Fi (and) surface convexities. Alternatively, the present invention provides a method for manufacturing an aluminum alloy part.

FIG. 1 is a perspective view of an example of an aluminum member showing a part of a corner, and FIG. 2 is a perspective view of an example of an aluminum member showing a surface convex portion and a part of a corner.

In the figure: 1... Aluminum member, 2... Part of corner, 3... Surface convex part.

Agent: Patent attorney Hidema Kuwahara Figure 1 Figure 2 ■

Claims (1)

[Claims] An aluminum or aluminum alloy member having a colored oxide film layer is coated with a pigment having a color tone different from that of the film.
It was immersed in an organic solvent-based paint containing 5 to 7 wt%, a specific gravity of 0.9 to 1.2, and a surface tension of 20 to 30 dyne/min, and pulled up at a speed of 0.12 to 1.2 m/min. By performing baking finishing, an opaque colored coating is formed on the flat part of the member, and the colored oxide film surface of the aluminum or aluminum alloy member is coated through the colored coating on some corners and/or surface convexities. A method for manufacturing an aluminum decorative member, characterized in that it allows for twilling.