JPS62117737A - Surface-coated aluminum material - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a surface-coated aluminum material, and more particularly to an aluminum material used as a building material with improved durability.

Conventional technology Aluminum materials are used in various fields because they are less rusty and lighter than iron materials, but they are especially used in roofing materials,
It is often used as building materials such as interior and exterior wall materials and window sashes.

Aluminum materials used as building materials are
If the usage conditions are severe, such as when the product is exposed to wind and rain for a long period of time, corrosion of the surface is inevitable, and surface anti-corrosion treatment is applied to prevent this, but even this is insufficient. Therefore, in order to further improve the surface corrosion resistance and improve the appearance, the surface is coated with a resin film and used.

In order to manufacture aluminum plates coated with such resin films, conventionally the aluminum plates are degreased and treated to roughen the surface, then immersed in a chromate solution and dried. The surface is chromated and a resin film is provided on the chromated surface. The resin film is a fluororesin coating that has excellent physical properties such as outdoor weather resistance, bending workability, chemical resistance, solvent resistance, abrasion resistance, tΩ water resistance, stain resistance, non-adhesion, and corrosion resistance. It is also practiced to use

However, in a structure in which a resin coating film is provided on a chromated aluminum plate, the thickness of the chromate layer is less than 1 μm, and the resin coating does not improve the surface corrosion resistance of the aluminum plate. It can be said that it is applied to improve the adhesion of the coating film, but it is difficult to set the treatment conditions, and the reproducibility of the corrosion resistance performance of the treated film and the adhesion of the resin coating film is also poor. , Furthermore, not only do they have the disadvantage that their performance deteriorates rapidly over time, but
There is also the pollution problem of emitting hexavalent chromium.

In order to improve the above-mentioned problems associated with romate treatment, a so-called alumite plate, which is an aluminum plate anodized to form an oxide film on the surface, is used as the base material, and acrylic resin paint is sprayed or electroplated onto it. Resin-coated aluminum plates are also produced by coating.

In this surface coating method, the aluminum plate is colored by adding a coloring agent to the acrylic resin paint, and this coloring is done by anodizing the aluminum plate and then coloring it by electrolytic coloring using a so-called metal compound. It is particularly important for obtaining colored aluminum plates because it is more uniform in color than aluminum. Furthermore, this surface coating method becomes even more important when recycled and reused used aluminum materials because both anodic oxidation and electrolytic coloring are more likely to cause unevenness.

When an aluminum plate is anodized in this way, the oxide film can be changed arbitrarily from a few microns to several tens of microns, and it is possible to add a certain degree of corrosion protection while adjusting it, while maintaining its performance stably. This is a surface treatment method for aluminum plates that is superior to the above-mentioned chromate treatment without causing pollution problems. This type of anodizing treatment is carried out by aluminum board manufacturers, but even if aluminum boards that have been anodized in this way are used, they are not durable enough to be used, for example, as outdoor building materials. The oxidation treatment is followed by a surface coating treatment with an acrylic resin paint that can be processed on the same production line.

However, the service life of the acrylic resin-coated aluminum plates produced in this way is not extended to, for example, 10 to 20 years because the durability of the acrylic resin is not sufficient, and further improvements are desired. It was rare.

As mentioned above, a high-performance fluororesin coating is used for chromate-treated aluminum plates, and an acrylic resin coating is used for anodized aluminum plates because the alumite is coated with resin. The spraying or electrodeposition coating described above is carried out on the same production line as the oxidation treatment process for aluminum plates, so the paints used are limited to solution-type paints, and the fan resin described above is It is difficult to imagine using a dispersion-type paint like paint, but on the other hand, the painting of aluminum plates that have undergone the above chromate treatment is done on the same line as this chromate treatment, and these are done by a painting company, so it is difficult to imagine using a dispersion type paint. I couldn't easily think of using alumite for the material. In short, aluminum sheet manufacturers are familiar with the modification of aluminum sheets, but they are not familiar with the coating materials used, and painting companies are familiar with paint agents, but are not involved in the essential modification of aluminum sheets. I was not familiar with quality, and I wanted to understand and systematize the characteristics of both of these, and create advanced technical ideas that could not be thought of from these individual aspects. Conventional surface-coated aluminum boards, such as those that form a fluororesin coating film on an aluminum board whose base material is chromate-treated, have problems with the chromate treatment, etc. However, even the products that are used and have an acrylic resin coating formed on the surface do not meet the recent demands for durability, and are beyond the ordinary knowledge of aluminum F&W manufacturers and painting companies. It was hoped that the problem would be resolved from a position that transcended the situation.

Means for Solving the Problems In order to solve the above problems, the present invention provides a coating in which an oxide film is formed on an aluminum material, and a fluororesin layer containing fluororesin as a main component is formed on the oxide film. The present invention provides a surface-coated aluminum material characterized by being provided with a layer.

Next, the present invention will be explained in detail.

The surface-coated aluminum material of the present invention forms an oxide film on the aluminum material, and the aluminum material includes not only aluminum alone but also alloys containing 99% by weight or more of aluminum.

The oxide film may be, for example, an oxide layer mainly composed of T-alumina formed by anodic oxidation in a sulfuric acid solution, and the film thickness is 1 to 25 μm, preferably 2
~20μ is appropriate. If the thickness is too thick, cranking may occur during processing. Moreover, if too much N is used, the anticorrosion effect will be lowered.

Aluminum material -C having such an oxide film is also used because it is sealed, but after the above-mentioned anodic oxidation, for example, it is electrolytically colored using a metal compound, and then Those that have been sealed are also used.

In the case of recycled aluminum materials that are recycled from used aluminum materials, it is difficult to perform these anodic oxidation and electrolytic coloring uniformly, but such aluminum materials are also used in the present invention, and in this case, the present invention By providing the fluororesin layer of the invention, its durability is significantly improved.

In addition, in the present invention, a coating layer having a fluororesin layer containing fluororesin as a main component is provided, and this fluororesin layer is provided directly on the oxidized layer of the aluminum material as a single layer for this N layer. However, it is also possible to provide this fluororesin layer via an undercoat layer to make it 2N. Also,
These may be made into enamel by containing a coloring agent, and in this case, in addition to the 2N structure described above, a transparent top coat layer is further provided to make the structure three or more layers. You can also do that. The enamel coating layer can also be painted in multiple colors.

When providing the above-mentioned undercoat layer, it is desirable to provide an epoxy resin paint from the viewpoint of adhesion to the base material.
Acrylic/fluororesin paints can also be used, and various other resin paints such as polyester resins and modified fluororesins can also be used. Epoxy resins include epoxy/melamine resins, epoxy/urethane resins, and epoxy/phenolic resins, and acrylic resins include acrylic/melamine resins, epoxy/urethane resins, and epoxy/phenolic resins.
Urethane resins are also used. In this case, for example, chromium-based, boron-based, phosphoric acid-based, such as strontium chromate,
Cobalt-based rust inhibitors and small amounts of fillers (e.g. Cas M
It may also contain oxides of g, Al, Si, barium sulfate, etc.).

The fluororesin paint used when forming the fluororesin layer is, for example, a so-called solvent-type dispersion organosol in which a fluororesin is dispersed in a solvent, but is not limited thereto. The fluororesin used for these is tetrafluoroethylene (CF2/CFz).
, chlorotrifluoroethylene (CF2=ICFC), hexafluoropropylene (CF3-CP=CFz)
, To IJ ”7 JLt Ot: +! Chire 7 (CH
All fluorine-containing polymers obtained by homopolymerization of fluorine-containing monomers such as F, CFz), vinyl fluoride (CI (Z=CHF), and vinylidene fluoride (CF2=CHz) or copolymerization with other monomers) These include, for example, resins with a fluorine content of 20 to 60% by weight, such as polyvinylidene fluoride (fluorine content in the resin: 59% by weight), vinylidene fluoride, etc. and acrylic (7/3 copolymerization ratio) (fluorine content in resin 50% by weight), polyvinyl fluoride, and the like.

A thermosetting fluororesin is also used, and in this case, an example is given in which it is used in combination with a curing agent such as melamine, urethane, or epoxy (fluorine content in the resin is 20% by weight).

Other resins can also be used in combination with the above fluororesin,
These include thermoplastic resins such as acrylic resins, thermosetting acrylic resins, melamine resins, urea resins, and isocyanate compounds. Furthermore, one or more of each or both of a silane cuff pulling agent and a titanate coupling agent is added at 0.00% per 100 parts by weight of the fluororesin.
In addition, additives commonly used in paints such as coloring pigments, extender pigments, binder agents, organic solvents, surfactants, antifoaming agents, etc., may also be added singly or in combination. It is also possible to use a combination of more than one species.

Examples of the thermoplastic acrylic resin include polymers of acrylic esters and methacrylic esters, or copolymers thereof. In this case, the ester groups include methyl, ethyl, propyl, butyl, isobutyl, n-
Examples include hexyl, lauryl, stearyl and the like. The copolymer may contain one or more of these ester groups.

Thermosetting acrylic resins contain functional groups (carboxyl groups, hydroxyl groups, amino groups,
methylol group, epoxy group, etc.), such as acrylic acid, methacrylic acid, acrylamide, methacrylamide, N-methylol acrylamide, allyl glycidyl ether, glycidyl methacrylate;
Examples include, but are not limited to, polymers obtained by copolymerizing two or more monomers selected from two groups of styrene, acrylic esters, and methacrylic esters.

In the present invention, examples of the titanate coupling agent include isopropyl triisostearoyl titanate, isopropyl tridodecylbenzenesulfonyl titanate,
Isopropyl tris (dioctyl pyrophosphate)
Titanate, tetraisopropyl bis(dioctyl phosphite) titanate, tetraoctyl bis(ditridecyl phosphite) titanate, tetra(2,2-diallyloxymethyl-1-butyl) bis(di-tridecyl) phosphite titanate, bis(dioctyl) pyrophosphate) oxyacetate titanate, bis(dioctylpyrophosphate) ethylene natanate, isopropyltrioctanoyl titanate, isopropyl dimethacrylylisostearoyl titanate, isopropyl isostearoyl diacryl titanate, isopropyl tri(dioctylphosphate) titanate, isopropyl tricumylphenyl titanate , isopropyltri(N-aminoethyl-aminoethyl)titanate, dicumylphenyloxyacetate titanate, diisostearoylethylene titanate, and the like.

In addition, as a silane cuffing agent, vinyltrichlorosilane, vinyltriethoxysilane, T-chloropropyltrimethoxysilane, γ-chloropropylmethyldichlorosilane, γ-chloropropylmethyldimethoxysilane, γ-chloropropylmethyljethoxysilane , γ
-aminopropyltriethoxysilane, N-(β-aminoethyl)-r-aminopropyltrimethoxysilane,
N-(β-aminoethyl)-γ-aminopropylmethyldimethoxysilane, T-mercaptopropyltrimethoxysilane, γ-glycidoxypropyltrimethoxysilane, T-glycidoxypropylmethyldimethoxysilane, T-methacryloxypropyl Trimethoxysilane, γ
-Meccryloxybrobylmethyldimethoxysilane, vinyltris(β-methoxy-ethoxy)silane, β-(
Examples include 3,4-epoxycyclohexyl)-ethyltrimethoxysilane.

The above fluororesin paint may contain 0.01 to 10 parts by weight of one or more titanate camping agents or silane coupling agents per 100 parts by weight of the fluororesin. From the viewpoint of better preventing shrinkage of the coating film during the film forming process, it is preferably 0.1 part by weight or more, and if it is 5 parts by weight or more, there will be no noticeable difference in effect, so 0.3 to 2.0 parts by weight. Parts by weight are particularly preferred.

The above-mentioned fluororesin paint may contain other resins, titanate coupling agents, or silane coupling agents in addition to the above-mentioned fluororesin, but considering its suitability for coating, for example, polyfluorocarbon resin may be added to the fluororesin. When using vinylidene chloride resin, 10 to 60 parts of thermoplastic resin or thermosetting acrylic resin is added to 100 parts by weight of vinylidene chloride resin.
It is preferable to add parts by weight. At this time, various plasticizers may be added to maintain appropriate fluidity of the paint.

In addition, when the above fluororesin paint is supplied as a solvent-based dispersion organosol paint, a solvent is added, but this solvent composition determines the coating suitability, the fluororesin dispersion, the paint's viscosity, the flow characteristics, and the long term of the paint. It has a large influence on the storage stability of the paint, which indicates storage stability (the property that resin particles are stably dispersed in a dispersion medium and does not aggregate), and the coating film-forming ability, which indicates film-forming performance. Generally, a solvent having a polar group such as a ketone or ester solvent and an aromatic hydrocarbon solvent are used in combination.

In addition, as for the coloring agent that can be added to the above-mentioned fluororesin paint, any pigment can be used, but in order to take advantage of the properties of fluororesin such as heat resistance, chemical resistance, and outdoor weather resistance, it is necessary to use these pigments. It is preferable to use pigments having the same properties, and when using them, for example, 5 to 240 parts by weight can be added to 100 parts by weight of vinylidene borifuff. Metal powders such as aluminum powder and copper powder can also be used. When this metal powder is used, it is preferable to apply a tofu coat to prevent its oxidation.

When providing a top coat layer, all of the above-mentioned fluororesin paints except for colorants can be used. At this time, waxes, olefin-based synthetic resins, ultraviolet inhibitors, silicone-based repelling agents, etc. can also be included.

The above paints that require undercoat, fluororesin layer paint, and top coat are roll coating method, curtain coating method,
Spray painting method etc. are used.

In order to form the surface wave M layer on the surface-coated aluminum material of the present invention, each of the above-mentioned paints is applied, but the undercoat layer coating film can also be baked together with the fluororesin layer coating film, You can also print each item separately. Preferably, the top coat layer is baked.

When the coating film of the fluororesin layer is baked in this way, the fluororesin in the coating film is dissolved or swollen by the dimethyl phthalate, etc. contained in the coating film, and the particles of the fluororesin are fused and uniformly formed. On the other hand, dimethyl phthalate evaporates and disappears from the paint film. In this way, uniform fu.

When a base resin coating film is formed, the characteristics of the fluororesin, such as water repellency, corrosion resistance, weather resistance, non-adhesiveness, and stain resistance, are utilized. As a result, the corrosion resistance of the oxide film formed on the surface of the base material is maintained for a long time by blocking chemical substances and moisture contained in the atmosphere in which the aluminum material with the fluororesin coating is used. At the same time, the adhesive base of the fluororesin coating film is maintained firmly, so its function can be maintained for a long time. In this way, both of them act synergistically, and when these individual effects are added together, it is possible to exert a remarkable effect that is more than expected.

Effects of the Invention As explained above, in the present invention, a coating layer having a fluororesin layer mainly composed of fluororesin is provided on an aluminum material on which an oxide film is formed, so that its durability as a base material is improved. At the same time, the durability of the coating film is improved, and the overall durability of the combination of these can be significantly improved.This allows for example to double the useful life of the building material compared to conventional materials. We can provide an innovative material that can be used for a long time, extending the maintenance-free period of high-rise buildings, further increasing its effectiveness, and meeting recent demands.

Example The present invention will be explained in detail below with reference to Examples.

Example 1 An aluminum plate is immersed in an electrolyte bath of 15% by weight sulfuric acid aqueous solution, and this is used as an anode, and a nickel plate is used as a cathode to pass 12ν of direct current, and if necessary, superimpose some alternating current for electrolytic treatment.゛The potential gradient of this raw ore dissemination layer is not considered. As the electrolytic treatment is carried out, anodic oxide is generated on the surface of the aluminum plate, but when the thickness reaches 3 μm, the electrolysis is stopped and the aluminum plate is lifted out of the electrolyte bath.

This aluminum plate was dried to obtain an anodized aluminum plate. After applying the undercoating paint shown in Formulation Example 4 and baking it (200°C for 10 minutes), applying the fan resin paint of Formulation Example 1 and baking it (250°C for 15 minutes), this Example 1
A surface-coated aluminum plate was obtained. The preparation conditions are summarized in Table 1. Regarding this, the following test was conducted and the results are shown in Table 3.

+1) Convex adhesion test A test piece is scratched with a knife in 11 vertical and horizontal lines with an IN width in the shape of a substrate pattern, adhesive tape (Cello tape) is applied, and when this is peeled off, the coating film does not peel off. 5.0-20
% peeling was rated as 4. 20-40% peeling was 3.40-60% peeling was 2.60% or more peeling was rated as 1.

(2) Processability test When the test piece is bent in a vise, a grade of 5 is given for those with no cracks in the coating film, 1 is given for those with scratches on the entire surface, and 4, 3, and 2 are given in between depending on the degree of cracking. did.

(3) Chemical resistance test In the same way as in (1), scratch the test piece in the shape of the substrate, and use 1% sulfuric acid.
Those with no damage after being immersed in the solution for 24 hours were graded as 5, those with full damage as 1, and those in between as 4, 3, and 2 depending on the degree of damage.

(4) Cath test According to JISDO 201, test pieces were kept in a mist of 5% saline, cupric chloride, and acetic acid solution for 500 hours, and those with no damage to the coating were rated 5, and those with full damage were rated 1. The intermediate level was graded as 4.3.2 depending on the degree. At this time, the test pieces used were one in which the paint film was scratched with a knife (cut part), one in which the paint film was peeled off with a 1,000 yen coin (peeled part), and one in which the paint film was not scratched (flat part). .

(5) Salt water spray test According to JIS Z2351, the test pieces were held in a salt water mist, and three types of test pieces were tested and evaluated in the same manner as in (3) above.

Examples 2 to 5 In Example 1, each of Examples 2 to 5 was used instead of the items described in each item in the Example 1 column of Table 1.
Surface-coated aluminum plates of Examples 2 to 5 were obtained in the same manner, except that the items described in the corresponding sections were used. The same test as in Example 1 was also conducted for this, and the results are shown in Table 3.

Comparative Examples 1 and 2 An aluminum plate is immersed in a halogen-based etching agent for 1 minute, then washed with water, then immersed in a treatment solution containing sodium dichromate as a main component for 2 minutes, washed with water, and then dried.

Using this chromate treatment, surface-coated aluminum plates of Comparative Examples 1 and 2 were obtained in the same manner as in Example 1 except for the conditions shown in Table 2, and the same tests as in the Example were also conducted. The results shown in Table 3 were obtained.

Comparative Example 3 Using the anodized aluminum aluminum plate prepared in Example 1, a surface-coated aluminum plate was obtained in the same manner as in Example 1 except for the conditions shown in the relevant column of Table 2. A similar test was conducted and the results are shown in Table 3.

Formulation example 1 Enamel (weight%, same below) Acrylic resin (solid content 100%) 9.0 xylene
13.5 Stir and dissolve these. Next, titanium white (pigment) 14.5 was added and milled using a ball mill. To this, dimethyl phthalate 5.0 diacetone alcohol
15.0 Butyl Cellosolve
Add 7.0 polyvinylidene fluoride powder 24.0 and stir vigorously. Furthermore, xylene 5.0 toluene
Add 7.0 for a total of 100 (
%).

Formulation Example 2 Enamel acrylic resin (solid content 100%) 15.5 xylene 22.5 These are stirred and dissolved. Next, Titanium White (R material) 13.0 was added and milled using a ball mill. To this, dimethyl phthalate 5.0 diacetone alcohol
11.0 Butyl cellosolve
3.0 Polyvinylidene fluoride powder 15.0 is added and stirred vigorously. Furthermore, add toluene 15.0,
The total is 100 (%).

Formulation example 3 Enamel (metallic paint) Acrylic resin (
Solid content 100%) 13.0 xylene
19.5 Stir and dissolve these. Next, 3.5 ml of carbon blank (pigment) was added and milled using a ball mill. To this, dimethyl phthalate 5.0 diacetone alcohol 11.0 butyl cellosolve
4.0 Polyvinylidene fluoride powder 3
Add 0.3 and stir vigorously. Furthermore, add 5.7% of aluminum paste (not 65% of aluminum!'A) and 8.0% of toluene and stir to make a total of 100(%).

Formulation Example 4 40% solution of undercoat Epicoat 1009 50.0 Titanium white (pigment) 15.0 Strontium chromate (rust-preventing pigment) 4.0 These are ground in a ball mill.

Butylated melamine resin (solid content 60%) 8.0 Cellosolve acetate 8.0 Diacetone alcohol 8.0 Cyclohexanone
Add 7.0 and stir to make a total of 100 (%
).

Formulation Example 5 Topcoat wear paint acrylic resin (solid content 100%) 12.0xylene 18°O is stirred and dissolved.

Dimethyl phthalate 4.5 Diacetone alcohol 12.0 Butyl cellosolve 12.0 Toluene
12.0 Polyvinylidene fluoride powder 2
Add 9.5 and stir vigorously to make a total of 100 (%).

The above acrylic resin is a copolymer of 872 of methyl methacrylate and ethyl acrylate (Paraloid B4).
4 (Rohm & Haas Co., Ltd.), Holif, vinylidene powder is Kynar 500 (manufactured by Penn Ortho Co., Ltd., Epicor), and 1009 is an epoxy resin made by Yuka Shell Epoxy Co., Ltd.

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Claims (2)

[Claims] (1) A surface-coated aluminum material, characterized in that an oxide film is formed on an aluminum material, and a coating layer having a fluororesin layer containing fluororesin as a main component is provided on the oxide film. (2) Claim 1, characterized in that the coating layer has a fluororesin layer via an epoxy resin undercoat layer.
The surface-coated aluminum material described in Section 1.