JP2010024536A - Surface treatment method for aluminum material, and surface-treated aluminum material - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a surface treatment method for an aluminum material with a decorated surface in which a pattern having ruggedness is formed and which has excellent design properties, and to provide an aluminum material obtained by the same method, and which is lightweight, has no problems in the peeling and falling of a decorated surface, and can produce even in a long-length product. <P>SOLUTION: The surface treatment method for an aluminum material includes: forming a film on the surface of an aluminum material by anodic oxidation treatment or chemical conversion treatment, thereafter; if required, primary coating using a coating material comprising an epoxy resin; next, performing intermediate-coating of forming a pattern having ruggedness using a coating material composition comprising a coloring agent, an aggregate and a fluorine resin; and further, applying a clear coating to the intermediate coating surface using a fluorine resin-containing coating material. Also, an aluminum material surface-treated by the surface treatment method is provided. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a surface treatment method for an aluminum material, and an aluminum material that is surface-treated by the surface treatment method. More specifically, the present invention relates to an aluminum material having excellent characteristics such as excellent design and decoration, light weight, safety and durability by treating the surface of the aluminum material with a specific method. Is.

Building materials with various designs are used for the inner and outer walls of buildings.
For example, the wall surface is finished with old-fashioned plaster (see Patent Document 1), a flat plate cut out of marble, granite, sandstone or the like is attached to the wall surface, or a plaster board, cement board, mortar board, calcium silicate board For example, these natural stone powders and granules are applied together with a binder to create a stone-like atmosphere (see Patent Documents 2 and 3), or ceramic raw material powder on the surface of the ceramic raw material molded body After adhering the particles, the ceramic decorative material is fired and used as a decorative material for the inner and outer walls of the building (see Patent Document 4).

However, since the plaster is manually performed after the wall surface is completed, there is a problem in durability such that it requires skill, and is cracked or easily peeled off due to drying or earthquake.
In the method of using a flat plate cut out of natural stone, these stones themselves are very expensive and become heavy, so workability is poor, and in addition, it is necessary to take measures against scattering due to falling or breakage during an earthquake . Moreover, it is difficult to obtain a long object.
In the method of adhering powdered or granular materials of natural stone to gypsum board, cement board, mortar board, calcium silicate board, etc., these substrates have water absorption and moisture absorption, resulting in dimensional changes and cracks. As a result, there are problems such as contaminants penetrating and adhering to the cracks, and whitening components of building materials leaching out to the surface of the coating film to cause whitening. Moreover, as a whole, it has been provided with almost uniform patterns and colors, and has not yet reached a monotonous, natural stone-like makeup surface.
In the method using the ceramic decorative material, the yield when producing the ceramics is poor, resulting in an increase in cost and a long delivery time. In addition, it is necessary to take measures against falling due to earthquakes and natural degradation. In addition, it is practically difficult to manufacture a long object exceeding 2 m.
On the other hand, with respect to a method for forming a pattern design on aluminum or an alloy thereof, a method of forming a pattern on the surface by the composition of the substrate, heat treatment, extrusion conditions, etc. (see Patent Document 5 below), a pattern forming method using a paint, In addition, a method of printing or transferring a pattern onto a film and fixing it has been proposed. However, in any of the methods, the color tone and the type of the pattern are limited, and the pattern can only be obtained in a plane.

JP 2001-192255 A JP-A-11-62163 JP-A-5-279149 JP 2001-322884 A JP 05-70906 A

  The present invention provides a surface treatment method for an aluminum material having a decorative surface excellent in design and decorativeness, and a lightweight, decorative peeling or dropping of a decorative surface, from the formation of an uneven pattern. It is an object of the present invention to provide an aluminum material that is durable and that can be manufactured even for long objects.

The inventors of the present invention have completed the present invention as a result of intensive studies in order to achieve the above object, and the gist thereof is as follows.
1. After forming a film on the surface of the aluminum material by anodizing treatment or chemical conversion treatment, an intermediate coating is performed to form a pattern having irregularities using a coating composition containing a colorant, an aggregate, and a fluorine resin, Furthermore, the surface treatment method of the aluminum material characterized by performing clear coating on the said intermediate coating surface using a fluorine resin coating material.
2. 2. The surface treatment method for an aluminum material according to 1 above, wherein primer coating is performed on the anodized surface or chemical conversion surface using an epoxy resin coating, and then the intermediate coating is performed.
3. 3. The surface treatment method for an aluminum material according to 1 or 2 above, wherein the anodized surface or chemical conversion surface is further subjected to electrolytic coloring treatment, and then primer coating is performed using an epoxy resin paint.
4). The aluminum material by which surface treatment is carried out by the surface treatment method in any one of said 1-3.

  ADVANTAGE OF THE INVENTION According to this invention, since the pattern which has an unevenness | corrugation can be formed, the manufacturing method of the aluminum material which has a decorative surface excellent in the designability and the decorating property can be provided. Further, it is possible to provide an aluminum material obtained by the above method, which is lightweight, has no problem of peeling or dropping of the decorative surface, is safe and durable, and can be manufactured even with a long object.

The present invention is described in detail below.
The present invention provides an intermediate coating in which a film is formed on the surface of an aluminum material by anodizing treatment or chemical conversion treatment, and then a pattern having irregularities is formed using a coating composition containing a colorant, an aggregate, and a fluororesin. The present invention relates to a surface treatment method for an aluminum material that performs coating and further performs clear coating on the intermediate coating surface using a fluorine resin coating.
In the present invention, aluminum is used as a base material for building materials. In general, gypsum board, cement board, mortar board, calcium silicate board, etc. are used as building materials for exterior wall decoration, but these are water-absorbing and hygroscopic, resulting in dimensional changes and cracks. In addition, contaminants penetrate into and adhere to the cracks, and the whitening component of the building material leaches out to the surface of the paint film, causing a whitening phenomenon. However, the aluminum material employed in the present invention does not have such a phenomenon, is lightweight, and can be easily attached to and detached from the wall surface.
The shape of the aluminum material is not particularly limited as long as the surface treatment method of the present invention can be applied. For example, a flat plate or a tube (a square tube having a square or rectangular cross section, a circular tube having a circular or elliptical shape, etc.) ), Bars (round bars, square bars, etc.), and processed products such as extruded shapes can also be used.
The aluminum substrate employed in the present invention is aluminum or various aluminum alloys obtained by mixing copper, manganese, silicon, magnesium, or the like with aluminum. Examples of the aluminum alloy include ternary aluminum alloys such as aluminum-magnesium-silicon and aluminum-zinc-magnesium.

The surface of these aluminum materials is first degreased by a solvent degreasing, acid degreasing, weak alkaline degreasing or electrolytic degreasing as necessary to clean the surface. Next, an etching process is performed to remove the natural oxide film on the surface, thereby improving adhesion. The etching treatment is usually performed by immersing in an aqueous sodium hydroxide solution maintained at an appropriate temperature. Generally, it is carried out at 30 to 70 ° C. for about 3 to 20 minutes using a sodium hydroxide aqueous solution containing about 30 to 150 g / L of sodium hydroxide containing 5 to 20 g / L of dissolved aluminum.
Next, desmutting treatment for removing smut generated during the etching treatment is performed using an acid solution such as nitric acid or sulfuric acid. The degreasing, etching, and desmutting processes are not essential and can be performed as necessary.

Thereafter, the surface of the aluminum material is anodized to form an anodized film, or a chemical conversion treatment is performed to form a chemical film.
In the anodizing treatment, an aluminum material is connected to the anode in an electrolytic solution containing one or more of an inorganic acid such as sulfuric acid and phosphoric acid, or an organic acid such as oxalic acid, preferably in an electrolytic solution containing sulfuric acid. This is performed by applying a direct current, an alternating current, or a pulse current.
The anodizing conditions may be selected according to a conventional method according to the type, concentration, etc. of the electrolytic solution. In general, an electrolytic solution containing 100 to 300 g / L of sulfuric acid and 5 to 30 g / L of dissolved aluminum is used. 10-60V, current density 1-10 A / dm ² , treatment time 5-60 minutes, temperature 10-70 ° C.
In addition, although this anodic oxidation treatment method is the same operation as a treatment method generally called alumite treatment, the film thickness of the oxide film in the alumite treatment generally performed is about 10 to 25 μm. Such a thick film is not required and is about 3 to 15 μm. The purpose of this is to improve the adhesion with the primer or intermediate coating applied in the subsequent process, together with the anticorrosion, although the general anodized treatment is exclusively aimed at the corrosion protection of the aluminum material. It is to do. For this reason, in this invention, electrolytic treatment time can be shortened rather than a general alumite process.
By the anodizing treatment, a porous film having innumerable fine pores can be formed on the surface of the aluminum material.
On the other hand, as a chemical conversion treatment method, a chromate treatment and a method using chromium chromate are known, but among these, chromate treatment is usually 0.1 to 40 mg / L of chromic anhydride at room temperature. After immersing an aluminum material for several seconds to several tens of seconds in a chromate treatment solution containing sulfuric acid 0.3 to 30 gm / L, nitric acid 0.1 to 10 mg / L, and other necessary phosphoric acid, hydrofluoric acid, etc. It is carried out by leaving it in the air, washing it with water and drying it by heating.
Moreover, the method using chromium chromate uses chromium chromate instead of the above-mentioned chromic anhydride.
In the present invention, either of the above-described methods can be adopted as the ground treatment method. However, in the chemical conversion treatment, since a harmful substance such as chromium is used, measures such as employing a closed system are taken. There is a need. Therefore, it is desirable to employ an anodizing treatment that can perform the base treatment without using such a harmful substance.

Next, the following temporary sealing may be performed as it is, but the coating formed by anodizing treatment may be made inconspicuous even if it is damaged by performing electrolytic coloring treatment. Further, in order to make the scratches inconspicuous, it is preferable to color a base color having a brightness equivalent to that of the top coat.
As electrolytic coloring treatment conditions, the anodized aluminum material is immersed in a treatment solution in which a metal salt is dissolved, and direct current, alternating current, asymmetrical alternating current, pulse wave current, and the like are applied. current density 0.1~5A / dm ² about the processing time of about 10 to 500 seconds, and the temperature 20 to 70 ° C. approximately.

As described above, after the anodizing treatment, an electrolytic coloring treatment is preferably performed, and then a water-washing treatment, a dipping treatment in boiling water for a short time, or a temporary sealing by chemical treatment is performed to complete the coating base. The hot water washing treatment is performed by bringing pure water having a temperature of about 70 to 95 ° C. into contact with the aluminum material for about 1 to 20 minutes.
As compared with the sealing performed normally after the alumite treatment, the temporary sealing may be performed only by sealing half of the fine holes as a guide. When completely sealed, the adhesion with a primer or intermediate coating applied in a subsequent process becomes inferior, which is not preferable.
As a result, an oxide film excellent in corrosion resistance and adhesion is formed on the surface of the aluminum material, and a coating base can be formed.

Next, pattern coating is performed on the coating base.
The pattern coating consists of primer coating, intermediate coating (1 to 3 times), and clear coating.
Among these, the primer coating can be omitted, but it is preferable to perform the primer coating because the adhesion between the base and the coating portion formed by the intermediate coating is more reliably improved.
In the case of performing primer coating, in the present invention, as a primer, chlorinated polyolefin such as chlorinated polyethylene and chlorinated polypropylene, acid-modified polyolefin such as maleic anhydride-modified polypropylene, ethylene-based ethylene / ethyl acrylate copolymer, etc. Copolymers, organometallic compounds (such as ethyl α-cyanoacrylate), phosphite compounds, epoxy resin coatings, mixtures of polyethyleneimide and polyepoxy derivatives, mixtures of chlorinated polypropylene and acrylamide copolymers, PVC Examples thereof include a mixture of a copolymer and a polyester copolymer, a urethane emulsion, and an acrylic copolymer. Among these, it is preferable to use an epoxy resin paint that exhibits good adhesion and excellent corrosion resistance.
The primer coating is performed by uniformly applying the primer to the surface of the ground aluminum material using a spray, a brush, a roller, or the like.

Next, an intermediate coating is performed. In the intermediate coating, a coating composition containing a fluororesin as a colorant, an aggregate, and a binder is used according to the design to be expressed.
In the present invention, by adding aggregate to the intermediate coating, natural stone pattern, brick-like, tile-like, wood-grained, sandstone-like, sprayed lysine-like, corrugated, speckled, wind-like, fabric pattern, brush It is possible to express a texture pattern having irregularities such as a tone and a three-dimensional network tone.
As such aggregates, silica powder, cold water, crushed stones and bricks, shirasu, silica sand, wood powder, or ceramics obtained by firing and coloring if necessary can be used.
The shape of the aggregate can be freely adopted according to the design to be expressed, such as granular, powder, pellet, square, and lump.
Depending on the design to be expressed, the size of the aggregate is usually about 0.1 to 5 mm in diameter in the case of granules, and about 0.1 to 1 mm in diameter and about 1 to 5 mm in length in the case of pellets. Adopted.
As the colorant, various pigments and paints including color pigments and extender pigments can be used.
Examples of the color pigment include titanium dioxide, bengara, yellow lead, chrome green, ultramarine, mars violet, cobalt blue, and carbon black. Examples of extender pigments include marble powder and ceramic powder. Furthermore, you may use metal pigments, such as scaly foil pieces, such as aluminum and brass. Moreover, you may add the dispersing agent for coloring agents, another modifier, etc. as needed.
By selecting the color tone of the colorant, the appearance of the aluminum material can be freely selected, such as a ceramic tone, unglazed tone, and stone tone.

Fluorocarbon resin as binder is trifluoroethylene-vinyl ether, tetrafluoroethylene-vinyl ether, trifluoropropylene-vinyl ether, tetrafluoropropylene-vinyl ether, trifluoroethylene-vinyl ester, tetrafluoroethylene Examples include vinyl ester, trifluoropropylene-vinyl ester, tetrafluoropropylene-vinyl ester, trifluoroethylene-ethylene, tetrafluoroethylene-ethylene, polyvinylidene fluoride, and polychlorotrifluoroethylene. Of these, examples of the trifluoroethylene-vinyl ether fluororesin include “Lumiflon” manufactured by Asahi Glass Co., “Bonflon” manufactured by AGC Co-Tech Co., Ltd., and the like.
In the present invention, only the fluororesin may be used, but depending on the required performance of the intermediate coating, in addition to the fluororesin, conventionally used acrylic resin, urethane resin, acetic acid Vinyl resins, vinyl chloride resins, polyester resins, polyamide resins and the like can also be used in combination. However, even when these resins are used in combination, it is necessary that the fluororesin be the main component (the content of the fluororesin exceeds 50 mass% in the intermediate coating composition).
In addition, you may add a filler as needed. Examples of such fillers include powdery materials such as silica, alumina, and glass, clays such as kaolinite, montmorillonite, and vermiculite, flat materials such as mica, and fibrous materials such as glass fibers.
These components are added to a solvent such as an organic solvent or a mixed solvent of water and a petroleum solvent, and mixed and stirred to produce a coating composition for intermediate coating.
As content of each component in the said coating composition, 0.2-8 mass% of coloring agents, 1-70 mass% of aggregates, 0-80 mass% of fillers, and about 10-70 mass% of fluororesins are standard. And In addition, as other additives, generally used surfactants, dispersants, curing accelerators, antifoaming agents, and the like may be added.
The intermediate coating composition as described above is finally prepared using a thickener such as methylcellulose or methylhydroxypropylcellulose so as to exhibit a viscosity suitable for the following coating method. , Having a viscosity of about 50,000 to 50,000 cps.
The intermediate coating thus obtained is applied directly or after primer coating on the surface of the aluminum material. The aggregate, colorant, and fluororesin are sufficiently mixed to obtain a coating composition, which is then applied by spraying using a spray or the like, brush coating, roller coating, or trowel coating. At that time, in order to emphasize the concavo-convex pattern, it is preferable not to apply uniformly, but to apply a portion where the coating amount becomes coarse and a portion where the coating amount becomes dense.
In the method of the present invention, a patterned coating film having a coating thickness of about several tens of μm to 5 mm can be formed.
Although it may be applied only once, in order to form a pattern with irregularities more reliably, it is applied about 2 or 3 times with or without changing the coating composition in accordance with the usual method, and the coating surface is formed in multiple layers. It is desirable to make it. In particular, it is desirable to perform the second and third intermediate coatings so that the first intermediate coating is transparent.
The temperature during intermediate coating is about room temperature to about 80 ° C, and the drying time is about room temperature to about 150 ° C.
If necessary, the surface may be further mechanically patterned using a trowel, a roller, a comb, a broom or the like. Examples of the pattern include ripples, running water, stripes, standing waves, and wind ripples, and the uneven pattern can be further emphasized.

After the intermediate coating is dried, the intermediate coating surface is further subjected to clear coating using a paint containing a fluororesin.
This clear coating is performed in order to enhance durability, such as preventing the adsorption of dirt due to moisture of the aluminum material obtained in the present invention and preventing scratches on the surface. In the present invention, the clear coating contains a fluorine resin. Use paint to make. In the present invention, the gloss of the surface can be dealt with from lustrous to matte by performing clear coating. In clear coating, acrylic resin-containing paint is generally used. However, when this acrylic resin-containing paint is applied to the outer wall, a whitening phenomenon appears in about 10 years, especially for high-rise buildings. Is problematic in terms of durability.
On the other hand, in the present invention, both the intermediate coating and the clear coating have long-term durability by using a fluorine resin-containing coating.
Since the surface-treated aluminum material has the same material and shape as that of the conventional aluminum material, it can be used in the same manner as the conventional aluminum material, and can be easily removed and attached.

  As described in detail above, the surface treatment method for an aluminum material provided by the present invention can provide a method for producing an aluminum material having a decorative surface with a pattern having irregularities and having an excellent decorative surface. it can. In addition, the aluminum material obtained by the method is a highly durable aluminum material having a decorative surface excellent in design, in which a pattern having irregularities is formed, and is lightweight and has a problem of peeling or dropping of the decorative surface. Therefore, it is possible to provide an aluminum material that can be easily attached and detached and can be manufactured in a short time even for a long object.

EXAMPLES Next, although an Example demonstrates this invention further in detail, this invention is not limited at all by these examples.
Example 1
The test was carried out using an aluminum material made of a square pipe (length 60 mm × width 40 mm, thickness 3 mm, outer R4 mm, inner R1 mm) using an A6063-T5 material defined in JIS H4100 as an aluminum base.
First, the aluminum square pipe was pretreated. That is, using a weak alkaline degreasing agent (P.T580 FS1, manufactured by Henkel Japan Co., Ltd.) adjusted to 3 to 5% by mass, weak alkaline degreasing is performed at 40 ° C. for 5 minutes, and then at room temperature with water. Washed with water for a minute. Next, the said aluminum material was immersed in the liquid tank containing 70 g / L of sodium hydroxide maintained at 50 degreeC, and 10 g / L of dissolved aluminum, and left still for 10 minutes. Thereafter, the aluminum material was taken out and washed with water for 5 minutes at room temperature. Thereafter, it was neutralized by contacting with 150 g / L nitric acid at room temperature for 5 minutes. Finally, it was washed again with clean water for 5 minutes at room temperature to complete the pretreatment.
Next, anodizing treatment was performed under the following conditions.
Treatment solution: Contains 180 g / L sulfuric acid and 5 g / L of dissolved aluminum at 20 ° C. Electrolysis conditions: DC, constant current, current density of 1 A / dm ² for 20 minutes (final voltage is 14 V)
After completion of the anodizing treatment, it was washed with pure water for 5 minutes at room temperature. As a result, an anodized film having a thickness of 6 μm was obtained on the surface of the aluminum material. Thereafter, electrolytic coloring treatment was performed under the following conditions.
Treatment liquid: nickel sulfate 100 g / L, boric acid 30 g / L, pH 4.8, temperature 30 ° C.
First stage electrolysis conditions: asymmetrical alternating current (positive> negative), current density 0.2 A / dm ² , energized for 25 seconds Second stage electrolytic conditions: asymmetrical alternating current (negative> positive), current density 0.15 A / dm ² , 100 Energization for 2 seconds After completion of the second stage electrolysis, water was washed with pure water at room temperature for 5 minutes, and then contacted with pure water at 80 ° C. for 5 minutes to perform temporary sealing.
Next, pattern painting was performed. First, make sure that there is no moisture, oil, or powder on the base, and spray uniformly using a base material curing agent two-component reactive modified epoxy paint (manufactured by AGC Co-Tech) as a primer at room temperature. It was. When the primer layer was in a completely dry state, coating was performed using the following intermediate coating.
The composition of the intermediate coating used and the content of the entire coating are as follows.
Keisha (Brand name: Flatari Sand, manufactured by Nippon Steel Corporation) 65% by mass
Inorganic pigment (Brand name: Bayferrox, manufactured by Bayer) 1% by mass
Titanium dioxide (trade name: TCR-10, manufactured by Sakai Chemical Industry Co., Ltd.) 1.2% by mass
Fluorine-based emulsion binder resin (manufactured by AGC Co-Tech) 23% by mass
Other additives Antifoaming agent: Adecanate B190, manufactured by Asahi Denka Co., 0.5% by mass,
Thickener: UH420, manufactured by Asahi Denka Co., 1% by mass
Dispersant: Poise 530, manufactured by Kao Corporation, 0.5% by mass
7.8% by mass of water was added to these, mixed and stirred, and prepared so that the viscosity was 20000 CPS.
The coating was spray coating at room temperature, and was performed twice so that a coating film having a thickness of about 1 mm was formed.
After the intermediate coating surface was dried, clear coating was performed. In clear coating, spray coating was performed using a base material curing agent two-component reactive solvent fluororesin (manufactured by AGC Co-Tech).
As a result, the surface of the obtained aluminum material had irregularities, and a pattern having a transparent and three-dimensional ceramic (pottery) color tone was visually confirmed.

  The aluminum material surface-treated in the present invention can be used in various fields such as building members, civil engineering members, daily necessities, home appliance parts, vehicles, and ships because of its excellent quality and design. Especially in the field of construction and civil engineering, curtain walls, sashes, door products, interior / exterior wall materials, louver materials, exterior products (gates, fences, balconies, handrails, etc.), landscape products (poles, benches, Signs, fences, handrails, benches, etc.)

Claims (4)

  After forming a film on the surface of the aluminum material by anodizing treatment or chemical conversion treatment, an intermediate coating is performed to form a pattern having irregularities using a coating composition containing a colorant, an aggregate, and a fluorine resin, Furthermore, the surface treatment method of the aluminum material characterized by performing clear coating on the said intermediate coating surface using a fluorine resin coating material.   The surface treatment method for an aluminum material according to claim 1, wherein primer coating is performed on the anodized surface or chemical conversion surface using an epoxy resin coating, and then the intermediate coating is performed.   The surface treatment method for an aluminum material according to claim 1 or 2, wherein the anodized surface or the chemical conversion surface is further subjected to electrolytic coloring treatment, and then primer coating is performed using an epoxy resin paint.   An aluminum material which is surface-treated by the surface treatment method according to any one of claims 1 to 3.