JP2002177790A - Photocatalyst precoated molding material and photocatalyst precoated molding and photocatalyst precoated fin - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a photocatalyst precoated molding material which withstands molding, is hardly peelable and can be evenly provided with photocatalysts in necessary segments when made into molded goods and a molding and fins for heat exchangers using the same. SOLUTION: This material includes a metallic base material 1 which consists of aluminum or aluminum alloy, a ground surface layer 2 which is formed on the surface of the metallic base material and consists of either of a poreless anodically oxidized film or microporoous anodically oxidized film and a photocatalyst layer 3 which is formed on this ground surface layer. Further, the structure obtained by including a lubricating layer 4 formed on the photocatalyst layer 3 is possible as well.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a molding material having a photocatalytic layer having poor moldability, improving moldability, improving adhesion, and reducing gas or moisture release, and a molding precoated with the photocatalyst. The present invention relates to a heat exchanger fin made of a material.

[0002]

Electrons are excited in the surface portion of the photocatalyst light is touching the when irradiated air such BACKGROUND ART ultraviolet photocatalyst such as TiO ₂ and O ²⁺ or OH ^- is produced, decomposed organic matter by these It is known that a photocatalyst can provide a purifying function (action) such as antibacterial and purifying action. Such a photocatalyst is generally used in the form of fine particles or a film, and is used by being applied to the surface of a member requiring a purification function (action) or bonded with an adhesive.

On the other hand, antibacterial and antifungal properties have been required for air conditioner fins due to the recent hygiene boom or allergy countermeasures. From such a background, the inventor of the present application examined whether the photocatalyst can be applied to aluminum heat exchanger fins, and it was possible to apply the photocatalyst to the finished fin, but it was possible to apply the photocatalyst to the finished fin. In the method of applying the photocatalyst to the fins, it was difficult to uniformly apply the photocatalyst to the entire surface of the fins, resulting in a problem that productivity was poor.

[0004]

Therefore, the inventor of the present application has
Assuming that a photocatalyst was applied to an aluminum plate before forming the fins, and the plate was formed and processed to form fins, an aluminum plate coated with the photocatalyst was formed and processed to form a fin material. However, it was found that the adhesion between aluminum and the photocatalyst was extremely poor, and the surface smoothness of the photocatalyst was poor, so that the photocatalyst layer was easily peeled off from the aluminum plate during molding.

[0005] For this reason, even if an attempt is made to apply a photocatalyst to molded articles generally including fins, it is considered that the photocatalyst is easily peeled off at the time of molding, so that a photocatalyst is applied to an aluminum molding member before processing. Therefore, there is a problem that it is difficult to apply a photocatalyst to a molded member.

Further, the inventors of the present invention considered applying an anodized film (so-called alumite film) as a base layer on the surface of an aluminum plate material, and provided a photocatalyst layer after forming the anodized film. Research and development of the structure is underway. Non-porous and porous anodic oxide films of this type are known. Of these, a porous anodic oxide film is formed by growing a porous layer on a nonporous barrier layer formed on the surface of an aluminum plate. In such a case, the value obtained by dividing the area of the holes by the total area is known as the porosity, and about 60 to 70% of the porosity is widely used in a usual porous anodic oxide film. ing.

[0007] This kind of porous anodic oxide film is subjected to a sealing treatment of exposing it to hot steam in order to close the pores of the porous layer. It is said that the pores can be closed by exposing the porous layer to partial hydration and swelling the porous layer by exposing it to hot water in this way. In some cases, nickel or cobalt acetate or chromate is added to hot water to precipitate hydrates of these metals in pores to promote the sealing effect. However, in the porous anodic oxide film treated by the sealing treatment, moisture and other component ions remain in the sealed portion, so that the aluminum with the porous anodic oxide film is provided. When plate materials are used as various constituent members or vacuum equipment wall materials, moisture and component gases of various hydrates may be released from the surface of these structural members or from the wall surfaces of the vacuum equipment. The outgassing may be a problem.

Next, conventionally, a porous anodic oxide film generally has irregularities on its surface. Therefore, when another resin layer or film is laminated on the surface of the anodic oxide film, another resin As the bottom side of the layer or film is formed in a way that bites into the irregularities on the surface of the anodic oxide film, it exerts an anchor effect,
It has been considered that the adhesiveness of the resin layer or film laminated thereon is excellent. However, since the diameter of the pores existing on the surface of the porous anodic oxide film is considered to be extremely small, about several hundreds of mm, the resin layer or the film itself penetrates into such fine irregularities and the anchor effect. The present inventors believe that the porous anodic oxide film does not have good adhesion. Even if the sealing process is performed, moisture and ions remain in the pores of the porous layer. Therefore, another resin layer or film is laminated on the anodic oxide film, and during the laminating process. 100
When a drying process or a baking process is performed at a temperature of at least ℃ or more, the present inventors do not necessarily adhere to the resin layer or the film on the porous anodic oxide film due to the effect that water and ions in the pores volatilize or evaporate. We believe that the sex is not good.

Based on the above background, the present invention provides a film which can withstand molding, is hardly peeled off, has good adhesion to a film, has a low possibility of releasing moisture and gas, and has a portion necessary for a molded product. An object of the present invention is to provide a photocatalyst precoat molding material which can uniformly provide a photocatalyst and which is excellent in productivity, a molded article using the same, and a fin for a heat exchanger.

[0010]

In order to solve the above-mentioned problems, the present invention provides a metal base made of aluminum or an aluminum alloy and a porosity of 5 formed on the surface of the metal base.
% Of a non-porous anodic oxide film, and a photocatalyst layer formed on the under layer. O ²⁺ or OH ⁻ can be generated by exciting electrons at the surface portion of the photocatalyst layer that is exposed to light when exposed to air, and an action of decomposing organic substances can be obtained by these actions. Therefore, a purification function (action) such as antibacterial and purification action can be obtained by the photocatalyst over the entire surface of the photocatalyst molding material. In addition, by using a nonporous anodic oxide film having a porosity of less than 5% as a base layer,
The adhesion of the photocatalyst layer provided thereon is improved.

In order to solve the above-mentioned problems, the present invention comprises a metal substrate made of aluminum or an aluminum alloy and an anodized oxide film having a porosity of 5 to 30% formed on the surface of the metal substrate. It is characterized by comprising a base layer and a photocatalyst layer formed on the base layer.
O ²⁺ or OH ⁻ can be generated by exciting electrons at the surface portion of the photocatalyst layer that is exposed to light when exposed to air, and an action of decomposing organic substances can be obtained by these actions. Therefore, a purification function (action) such as antibacterial and purification action can be obtained by the photocatalyst over the entire surface of the photocatalyst molding material. Further, by using a microporous anodic oxide film having a porosity of 5 to 30% as a base layer, the adhesion of a photocatalyst layer provided thereon is improved.

In the present invention, it is preferable that a lubricating layer is formed on the photocatalyst layer. The provision of the lubricating layer can prevent the photocatalyst layer from peeling off or falling off when the photocatalyst precoat material is formed. In the present invention, the photocatalyst layer is made of TiO ₂ , ZnO, SnO ₂ , SrT
It is preferable that any one selected from iO ₃ , WO ₃ , Bi ₂ O ₃ , and Fe ₂ O ₃ is mainly used. In the present invention, the lubricating layer is preferably made of a nonionic polymer activator. The thickness of the lubricating layer of the nonionic polymer activator is preferably 0.02 μm or more.

The photocatalyst precoated body of the present invention comprises a metal substrate made of aluminum or an aluminum alloy, and a base layer made of a nonporous anodized film having a porosity of less than 5% formed on the surface of the metal substrate. And a photocatalyst precoat molding material comprising a photocatalyst layer formed on the underlayer and a lubricating layer formed on the photocatalyst layer. The photocatalyst precoated body of the present invention comprises: a metal base made of aluminum or an aluminum alloy; a base layer made of a microporous anodized film having a porosity of 5 to 30% formed on the surface of the metal base; A photocatalyst precoat molding material comprising a photocatalyst layer formed on a base layer and a lubricating layer formed on the photocatalyst layer is molded and processed, and the lubricating layer is removed after the processing. In the present invention, the lubricating layer may be removed after the forming process. The precoated fin of the present invention is obtained by molding the photocatalyst precoated material described in any of the above.

[0014]

Embodiments of the present invention will be described below with reference to the drawings, but the present invention is not limited to the following embodiments. FIG. 1 shows a first embodiment of a photocatalyst precoat molding material according to the present invention. A photocatalyst precoat molding material A according to the first embodiment comprises a plate-like substrate 1 made of aluminum or an aluminum alloy.
And a base layer 2 formed on the surface portion of the substrate 1, a photocatalyst layer 3 coated on the base layer 2, and a lubricating layer 4 coated on the photocatalyst layer 3. It is formed in a shape.

The substrate 1 is made of aluminum or an aluminum alloy, and is made of pure aluminum based on JIS1000, Al-Cu based on JIS2000, or JI.
S3000 type Al-Mn type, JIS4000 type Al-Mn type
Al-Mg based such as Si based, JIS 5000 based, JIS6
Any type of Al-Mg-Si type such as 000 type and Al-Zn-Mg type such as JIS7000 type may be used.

Pure aluminum-based materials such as JIS1000-based materials, JIS2000-based materials, JIS3000-based materials
Since the system is used for various parts, the present invention can be applied to the case where it is used for these uses.

Since the JIS 4000 type is used for building panels and the like, the present invention can be applied to these applications. The JIS 5000 type is widely used for interior / exterior boards, decorative parts, nameplates, etc., so that the present invention can be applied to these applications. Since JIS 6000-based materials are used for construction, decorations, and the like, the present invention can be applied to these applications. Since the JIS 7000 type is used for a fin or the like, the present invention can be applied to the case where it is used for these uses.

The photocatalyst precoat material A of the present invention
Among these applications, fins for heat exchangers that require mildew resistance, food containers that are kitchen aluminum products that require antibacterial and antifungal properties, range hoods, ventilation fan covers, range fences, Range cover, range underlay,
Alternatively, it can be used particularly effectively for various panels, BS antennas, and the like that require antifouling properties.

The underlayer 2 is formed by subjecting the substrate 1 to an anodic oxidation treatment. In this anodizing treatment (so-called alumite treatment), an anodized film is formed by anodizing treatment in which aluminum or an aluminum alloy constituting a base material is immersed in an electrolytic solution to perform anodizing. By such anodizing treatment, a nonporous anodized film (porous alumite film) having a porosity of 5% or less, or a porosity of 5 to 30% (more than 5% and 30% or less) A microporous anodized film (microporous alumite film) can be formed. Here, the porosity is a value obtained by dividing the area of the portion where the holes are formed in the measurement region on the surface of the anodic oxide film by the total measurement area, that is, porosity = (area with holes) / ( (Measured area). A method for producing a nonporous anodic oxide film having a porosity of 5% or less by anodizing treatment,
The method for producing the microporous anodic oxide coating of 0.1% will be described later.

The underlayer 2 is for preventing the adhesion between the substrate 1 and the photocatalyst layer 3 from being reduced, and the adhesion between the substrate 1 and the photocatalyst layer 3 for these layers is prevented. The presence of a bad oxide layer or the like causes problems such as the plasticity of the photocatalyst layer 3 peeling off during processing from the oxide layer. In this regard, if the undercoat layer 2 of the non-porous anodic oxide film or the microporous anodic oxide film described above has good adhesion to the substrate 1, of course, Also exhibit good adhesion. Here, if the film used as a base of the photocatalyst layer 3 is an organic film, the base layer is damaged by an organic substance decomposition action exerted by the photocatalyst layer 3.
It is necessary to use the underlayer 2 which is the above-mentioned inorganic layer and has good adhesion to the substrate 1 and further has good adhesion to the photocatalytic layer 3.

The photocatalyst layer 3 is made of TiO ₂ (titania), ZnO, SnO ₂ , SrTiO ₃ , WO ₃ , Fe ₂ O
₃ , a binder such as silica (mainly SiO ₂ ), zirconia (mainly ZrO ₂ ), or titanium peroxide is mixed with a photocatalytic semiconductor material selected from among the above _three materials. It can be obtained by means such as coating on the formation 2, drying, heating and baking. To apply these mixtures, conventional methods such as roll coating and gravure coating can be applied.

The thickness of the photocatalyst layer 3 is 0.05 to 1
It is preferable that the thickness be in the range of 0 μm. If the thickness of the photocatalyst layer 3 is less than 0.05 μm, it is not possible to secure a sufficient thickness as the photocatalyst layer 3 and it is difficult to obtain a purifying action such as antibacterial and antifungal performance. Further, if the thickness of the photocatalyst layer 3 is more than 10 μm, it has antibacterial and antifungal properties, but wastes a lot of material, which is disadvantageous in terms of manufacturing cost. Among these, TiO ₂ is harmless and chemically stable, and is excited by light by ultraviolet rays to surely exhibit antibacterial and antifungal effects, and exhibit an excellent purification function (action).

The lubricating layer 4 needs to be a layer containing a nonionic polymer activator such as polyethylene glycol, polyoxyethylene lauryl ether or polyvinyl methyl ether. The nonionic polymer activator used herein includes, for example, polyoxyethylene alkyl ether, polyoxyethylene alkyl phenyl ether, polyoxyethylene alkyl fatty acid amide, polyoxyethylene hydrogenated castor oil ether, polyoxyethylene 12-hydroxystearic acid Ester, polyoxyethylene alkyl fatty acid ester, polyoxyethylene rosin ester, polyoxyethylene glycerin alkyl fatty acid mono or diester, polyoxyethylene trimethylol propane alkyl fatty acid mono or diester, polyoxyethylene pentaerythritol alkyl fatty acid mono or diester, polyoxy Those selected from the group of ethylene polyoxyalkylene ethers are preferred. Further, among these, those having a haze number of 15.0 or more according to the Karabinos method due to the addition of ethylene oxide are preferred.
A nonionic polymer activator having a polyethylene oxide chain having a haze number of about 16 to 18 by the binos method is preferred.

When the above melting point is about 50-60 ° C., Karab
If the outermost layer has a lubricating layer 4 containing a nonionic polymer activator having a polyethylene oxide chain having a haze number of about 16 to 18 according to the inos method, lubricating properties during press working, especially drawless working It is possible to process a molded product such as a fin with good work efficiency and with high working efficiency. In addition, as an example of a method of manufacturing the nonionic lubricating layer 4 satisfying these conditions practically,
The manufacturing method disclosed in JP-A-7-041696 can be applied.

A predetermined amount of the nonionic polymer activator is dissolved in a solvent such as water, and the coating solution is roll-coated.
The photocatalyst precoat material A provided with the lubricating layer 4 having a cross-sectional structure shown in FIG. 1 can be obtained by applying and drying the photocatalyst layer 3 by an appropriate application means such as a gravure coat. The lubricating layer 4 after drying has a thickness of 0.02 μm or more,
Preferably, it is in the range of 0.02 μm to 1.0 μm. If the thickness of the lubricating layer 4 is less than 0.02 μm, the lubricity in the case of plastic working decreases, resulting in poor processing.
It is easy to cause seizure of the mold. When the thickness of the lubricating layer 4 is greater than 1.0 μm, there is no problem in lubricity, but the lubricant is easily wasted, which is disadvantageous in terms of manufacturing cost.

The photocatalyst precoat material A having the above-described structure can be processed into a required shape by plastic working such as press working, drawing, or ironing, and used for various purposes. In this plastic working, the lubricating layer 4 provided on the surface of the photocatalyst precoat material A reduces friction with a mold or a die during plastic working. Does not occur. Then, after molding into a desired shape, the processed product can be obtained by removing the lubricating layer 4 as necessary by means such as washing. The lubricating layer 4 may remain in the form of a molded product, or may be removed by means such as washing.

Since the molded article made of the photocatalyst precoat molding material A manufactured as described above has the photocatalyst layer 3 uniformly on the entire surface, the photocatalyst layer 3 is irradiated with energy light such as ultraviolet rays. Then, electrons are excited on the surface portion of the photocatalyst layer 4 which is in contact with air, and O ²⁺ or OH
^-Can be generated, whereby the action of decomposing organic substances can be obtained, and the photocatalyst can obtain a purifying function (action) such as antibacterial, antifungal and purifying action on the surface of the molded article.

Here, if the molded article is a fin for a heat exchanger, mold can be prevented from being generated on the fin.
A heat exchanger having fins exhibiting antibacterial properties and antifungal properties can be provided. In the case of a fin for a heat exchanger, since the fin is used in a state where water droplets adhere to the surface of the fin, even if the lubricating layer 4 remains on the surface portion after molding,
Since the lubricating layer 4 is gradually removed by water droplets, it is not necessary to particularly remove the lubricating layer 4. When the structure of the present embodiment is used as a molded product, it can be widely used as various molded product applications such as a range hood and a container in addition to the fin. In addition, it goes without saying that the photocatalyst precoat molding material A of the present embodiment can be widely applied to various uses described above as the constituent material of the base material 1. In this case, an excellent purification function (action) such as antibacterial and antifungal performance can be obtained regardless of the application.

FIG. 2 shows an example of a heat exchanger for an air conditioner having fins obtained by using the photocatalyst precoat molding material according to the present invention. The heat exchanger B of this example has a large number of fin members. A meandering tube 13 is arranged on a fin (photocatalyst pre-coated molded product) 14 having a laminated structure. The heat exchanger B having this structure is formed by fins 14 obtained by plastically processing the photocatalyst precoat molding material A described above.

When the fins 14 of the heat exchanger B are made of the photocatalyst precoat material A, the photocatalyst layer 3 is uniformly provided on the entire surface of the photocatalyst precoat material A. Antibacterial uniform over the entire surface of 14 ...
A purifying function (action) such as an antifungal action can be obtained. That is, if the photocatalyst layer 3 is previously applied to the entire surface of the aluminum plate or aluminum alloy plate before molding, the purification function (action) can be reliably obtained over the entire surface of the fins 14.

Next, a method for producing a nonporous anodic oxide film having a porosity of 5% or less to be used as the underlayer 2 and a porosity of 5%
A method for producing a 30% to 30% intermediate pore anodic oxide film will be described below. In the anodic oxidation treatment, in order to form a nonporous anodic oxide film having a porosity of 5% or less, it is difficult to dissolve the anodic oxide film to be formed and to form a nonporous anodic oxide film as an electrolytic bath. Aqueous solution in which one or more selected from the group of boric acid, borate, phosphate, adipate, phthalate, benzoate, tartrate, citrate, etc. are dissolved. Is preferably used. Among these electrolytic baths, boric acid, adipic acid, and phthalic acid are preferred in terms of properties of the oxide film, cost, and the like.

The concentration of the electrolyte during the electrolysis is selected from the range of 2% by weight to the saturation concentration of the electrolyte. An electrolysis bath temperature in the range of 15 to 50 ° C. is sufficient, and the bath temperature need not be as high as 50 ° C. or higher. During such electrolysis, the aluminum material is connected to a power source to perform anodic electrolysis so as to become an anode even if it is continuous or intermittent. An insoluble conductive material such as a carbon electrode is used for the cathode. As the electrolysis current, a direct current or the like is used. In the direct current electrolysis, the electrolysis is performed with a direct current density of about 1 to 20 A / dm ² and an electrolysis time of about several seconds to about 10 minutes.

The applied voltage is about 35 to 220 V, preferably about 60 to 1 V, since the thickness of the oxide film formed with respect to a voltage of 1 V in a DC current is about 14 °.
The range is 50V. 100 in terms of power supply etc.
V or less, and an anodic oxide film having excellent coating adhesion and corrosion resistance after coating can be obtained even by electrolysis at such a low voltage. This electrolytic treatment allows the aluminum material surface to have a thickness of 500 to 3000 mm, preferably a thickness of 800 to 3000 mm.
A uniform non-porous anodic oxide film of 2000 mm is formed.

The underlayer 2 of the anodic oxide film thus obtained is non-porous and has a porosity of at most 5%, usually about 2%. The water content of the anodic oxide film is 1 to 5% by weight, usually 1 to 5%.
It shows an extremely low value of 3% by weight. Further, the anion water content of the oxide film is 0.1 to 7% by weight, usually 1 to 5% by weight.
And a low value. On the other hand, a porous anodic oxide film obtained by a general sulfuric acid bath or oxalic acid bath has a porosity of 6%.
The water content is about 15% by weight after sealing, and the anion content is about 12 to 15% by weight.

For this reason, the undercoat layer 2 of this kind of nonporous anodic oxide film has excellent coating film adhesion. This is because moisture and anions volatilizing from the anodic oxide film are extremely small, and peeling of the coating film due to moisture and anions during baking at about 150 ° C. is eliminated. In addition, since it is nonporous, the corrosion resistance after coating is good. In order to form the photocatalyst layer 3 formed on the underlayer 2, a mixture obtained by mixing a binder with the photocatalytic semiconductor material as described above is applied on the underlayer 2, dried and heated. Baking means (use a roll coat or gravure coat for application)
Therefore, there is no possibility that moisture or ions are evaporated or volatilized from the underlayer 2 of the nonporous anodic oxide film at the time of this baking means. It won't be easy.

It should be noted that a two-stage operation may be performed in the electrolytic operation for forming the nonporous anodic oxide film. In that case, it is preferable to perform the constant current electrolysis first, and then to perform the constant voltage electrolysis at a voltage higher than the voltage at the time of the constant current electrolysis. As conditions for performing the electrolytic treatment under such conditions, the solute concentration is preferably 1.0 to 20.
0 g / l, and the electrolyte temperature is preferably 10 to 100
C., more preferably 20 to 50 ° C., and the current density of the constant current electrolysis is preferably 0.5 to 3 A / dm ² , more preferably 1 to 3 A / dm ² .
And ~2A / dm ^2, after the voltage in the constant current electrolysis rises to a predetermined value (e.g. 150~200V), performs constant voltage electrolysis and held at this voltage. The conditions at the time of the constant voltage electrolysis may be the same as those of the electrolyte solution or the temperature at the time of the constant current electrolysis. The voltage during constant voltage electrolysis is 35
To 220 V, more preferably 60 to 150 V, and the time is about 5 to 30 seconds, more preferably 10 to 20 V.
Seconds. By performing the two-stage electrolytic treatment under the above conditions, a nonporous anodic oxide film having a small amount of gas release, excellent in corrosion resistance and excellent insulating properties and excellent in coating adhesion can be obtained.

Next, the porosity used as the underlayer 2 is 5 to 5.
A method for producing a 30% microporous anodized film will be described below. In order to produce a microporous anodic oxide film, in the method for producing a porous anodic oxide film, electrolysis is stopped at a stage before the film is made porous, so that a step before the porous film grows is eliminated. It is preferable to carry out the method by obtaining a film having a state close to the porosity. As the electrolytic solution used here, one or more solutions of sulfuric acid, phosphoric acid, chromic acid, and oxalic acid can be used. When the base material 1 made of aluminum or an aluminum alloy is anodized using these electrolytic solutions, an anodic oxide film called a nonporous barrier layer grows in an initial stage of electrolysis, and this nonporous barrier layer grows. When the growth of the anodic oxide film proceeds to a predetermined stage,
The porous layer grows rapidly to form a porous anodic oxide film. However, in this specification, a porous anodic oxide film means a porous layer grown on a nonporous thin barrier layer.

Here, a growth model of this kind of porous anodic oxide film will be described with reference to FIG. The horizontal axis in FIG. 3 indicates the thickness of the anodic oxide film, and the vertical axis indicates the porosity. Usually, when a porous anodic oxide film is manufactured, a nonporous film having a thickness of about 1000 to 2000 ° is formed. A growth curve in which the porosity sharply rises while the film thickness hardly increases, and the relationship between the film thickness increase and the porosity increase shifts to a proportional relationship when the porosity exceeds 30%. Is shown. The growth curve shown in FIG. 3 is a model example of the anodic oxide film. After the formation, the porosity sharply increases, and then, when the porosity exceeds 30%, the relationship between the increase in the film thickness and the increase in the porosity shifts to a proportional relationship, and the porous anodic oxide film is formed. The tendency to do so is similar.

According to the growth model of the anodic oxide film shown in FIG. 3, in order to obtain a microporous anodic oxide film having a porosity of 5 to 30% to be used as the underlayer 2, it is necessary to increase the anodic oxide film during the growth process. In other words, the electrolytic treatment may be stopped in a state where the porosity is low. According to the growth model shown in FIG. 3, since the non-porous layer anodic oxide film having a porosity of 5% or less also exists in the initial stage of electrolysis, the production conditions of the non-porous anodic oxide film described above are not satisfied. Instead, the electrolysis may be stopped at the initial stage of the anodic oxidation treatment when the porous anodic oxide film described below is manufactured, so that the non-porous anodic oxide film may be obtained as the base layer 2. In order to obtain a microporous anodized film as the underlayer 2, for example, a film thickness of 10 to 1500
The electrolysis treatment may be stopped under the electrolysis conditions that fall within the range of 範 囲, for example, a porosity of 30% or less. Under these conditions, a more preferable range of the microporous anodic oxide film is a film thickness of 50 to 1000 ° and a porosity of 10%. The electrolyte used here may be one of sulfuric acid, phosphoric acid, chromic acid, and oxalic acid.
In the case of selecting one or two or more species, it is generally known that when the thickness (Å) of the anodic oxide film exceeds the value of the electrolytic voltage (V) × (14 to 16), porosity formation is started. . Therefore, if the film thickness is controlled below this voltage, a nonporous anodic oxide film or a microporous anodic oxide film can be formed. From this relationship, when manufacturing a microporous anodic oxide film, the film thickness (Å) is preferably set to be smaller than the electrolytic voltage (V) × 25,
It is more preferable to set smaller than the electrolytic voltage (V) × 18.

The thickness of the microporous anodic oxide film is 1
If it is less than 0 °, it is difficult to obtain corrosion resistance, and if the film thickness exceeds 1500 °, porosity is likely to progress. The preferred range is 10 to 1000 °. 5 to 3 in porosity
Even within the range of 0%, it is preferable to be more than 5% and not more than 20%. In the case of an anodic oxide film having a porosity of 5 to 20%, the water content of the anodic oxide film having a porosity of 20% to 30% is lower. There is an advantage that release can be more effectively suppressed, a decrease in the contact area can be prevented, and film destruction can be easily prevented. From such a viewpoint, the porosity of the microporous anodized film is 5 to 10
% (More than 5% and 10% or less) is preferable.

From the above background, the electrolyte concentration in the electrolytic bath when producing the microporous anodic oxide film is 2%.
It is selected from the range of weight% to the saturated concentration of the electrolyte. A bath temperature of the electrolytic bath of 5 to 30 ° C. is sufficient. In such an electrolytic solution, the aluminum material is connected to a power source and electrolyzed anodicly so as to be an anode even if it is continuous or intermittent. An insoluble conductive material such as a carbon electrode is used for the cathode. As the electrolytic current, a direct current or the like is used. In the direct current electrolysis, a direct current density of 0.5 to 1.5 A /
The electrolysis is performed in about dm ² and the electrolysis time is several seconds to about 10 minutes.

The applied voltage when producing the microporous anodic oxide film is about 10 to 20 V, since there is a relation that the thickness of the oxide film formed with respect to a voltage of 1 V is about 10 ° in the case of a direct current. It is preferably in the range of about 14-18V. By this electrolysis, a thickness of 10
A uniform microporous anodic oxide film having a thickness of ~ 1500 °, preferably 50-1000 °, is formed.

FIG. 4 is a model diagram of the cross-sectional structure of the porous anodic oxide film having a high porosity shown in FIG. 3, and FIG. 5 is obtained by setting the porosity shown in FIG. 3 to about 10%. It is a model figure of the cross-sectional structure of a microporous anodic oxide film near non-porous. The porous anodic oxide film 10 shown in FIG. 4 has a non-porous barrier layer 10a and a porous layer 10b grown thereon.
The microporous anodic oxide coating 11 shown in FIG. 5 has a cross-sectional structure in which some irregularities are present on the surface without growth of pores. Note that the microporous anodic oxide film 11 also has 5 to 30% of holes, so that the microporous anodic oxide film 11 has holes of this ratio. However, in FIG. 5, clear holes are not shown.

The microporous anodic oxide film 1 having the structure shown in FIG.
If it is 1, the gas release property is much smaller than the porous one, and a low gas release property close to the non-porous anodized film described above can be obtained. Further, when examining the anchor effect on the photocatalyst layer 3 laminated on the surface, the photocatalyst layer has an irregularity on the surface as compared with the nonporous anodic oxide film, and thus has a higher anchoring effect than the nonporous anodic oxide film. The adhesion of the layer 3 is also excellent. Of course, as described above, when the photocatalyst layer 3 is applied and baked because of low gas release property, there is little volatilization and evaporation of water and ions, so that it has a strong effect on peeling and peeling after baking.

[0045]

[Example] 1N30, 1 based on JIS-specified pure aluminum
Thickness of 100 μm, 200 μ made of 050, 1200 and JIS 3003 series, 3004 series aluminum alloy
A plurality of m and 300 μm aluminum substrates (substrates) were prepared. These various substrates were anodized under the following various conditions to form an anodized film. When a microporous anodic oxide film is to be formed,
50 g / l sulfuric acid solution, current density 1.3 A / dm ² ,
When forming a nonporous anodic oxide film, 100 g /
1 boric acid solution, and the current density was 3.0 A / dm ² . Under the above conditions, a microporous anodic oxide film having a thickness of 1000
Was obtained, and a non-porous anodic oxide film having a thickness of 800 mm was obtained.

The film thicknesses are obtained by embedding the sample in a resin, cutting the sample with a microtome, observing the cross section with a TEM, and directly measuring the film thickness. In addition, the method of measuring the porosity of the obtained non-porous anodic oxide film is to observe the surface with an electron microscope that can be magnified 100,000 times,
The area ratio of 20 arbitrary holes is measured and averaged. According to the measurement result obtained by this method, a nonporous anodic oxide film having a porosity of 2% is obtained. Rate was 10%. Next, a 0.5 μm-thick TiO ₂ layer (photocatalytic layer) is formed on the anodic oxide film on these various substrates, and then a 0.15 μm-thick lubricating layer is formed on this TiO ₂ layer. did. The photocatalyst layer was formed by mixing 50 parts by weight of a binder mainly composed of SiO ₂ with 50 parts by weight of TiO ₂ powder, applying the mixture to the surface of an aluminum substrate with a roll coater, heating to 150 ° C., and baking.

The lubricating layer was manufactured as follows. The following raw materials and catalyst are charged into an autoclave, and the air in the autoclave is replaced with nitrogen using nitrogen gas. Thereafter, the internal temperature of the autoclave is raised to 120 ° C., a specified amount of ethylene oxide is blown into the autoclave, the blowing is completed while maintaining the reaction temperature at 120 to 160 ° C., and then the reaction is completed at the same temperature for 1 hour. Thus, a nonionic polymer lubricant was obtained. The raw compound is rosin, the charge amount is 270 g, the number of moles is 0.1, and the catalyst is KOH.
The charged amount was 0.14, the ethylene oxide blowing amount was 880 g, the number of moles was 20 mol, and the yield was 900 g.

The obtained nonionic lubricant is a polyoxyethylene (200) ester. This polyoxyethylene (200) ester was coated on the photocatalyst layer so as to have a thickness of 0.15 μm. Further, Example 2 had a laminated structure equivalent to that of the sample of Example 1 except that only the thickness of the lubricating layer was 0.02 μm. Examples 1 and 2 are samples using a nonporous (2% porosity) anodic oxide film as a base layer, and the microporous anodic oxide film ( The porosity is 10%), and the other layers are made equal to each other by using a microporous anodic oxide film with respect to the sample of Example 3 and the sample of Example 2. Example 4
Sample.

A sample of Comparative Example 1 was the same as the sample of Example 1 except that the same substrate or underlayer and photocatalytic layer of aluminum or aluminum alloy were used, and only the uppermost lubricating layer was omitted. Comparative Example 2 Compared to the sample of Example 1, a structure (substrate + photocatalytic layer) in which both the underlayer and the lubricating layer were omitted was used.
And Compared to the sample of Example 1, the substrate, the underlayer, and the photocatalytic layer were equivalent, and a sample using a lubricant layer having a thickness of 0.01 μm was used as Comparative Example 3. A sample in which the underlayer was omitted from the sample of Example 1 and the photocatalytic layer and the lubricating layer were equivalent was designated as Comparative Example 4.

The samples of Examples 1, 2, 3, and 4 and the samples of Comparative Examples 1, 2, and 3 were subjected to a lubricity measurement test in which a coefficient of friction was measured with a Bowden friction tester. The results are shown in Table 1 below. In Table 1 below, the symbol 〇 indicates that the dynamic friction coefficient was 0.15 or less, and the symbol △ indicates that the dynamic friction coefficient was 0.16.
の も の 0.25, and × mark indicates those having a dynamic friction coefficient of 0.26 or more.

Further, these samples were continuously pressed using a volatile press oil (trade name: AF-2A, manufactured by Idemitsu Oil Co., Ltd.) using a fin press machine manufactured by Hidaka Seiki Co., Ltd.
When fins for a heat exchanger were molded using a 9.52φ drawless and a 9.52φ draw and the number of presses was set to 10000 shots, defective molded products and seizure to a mold were evaluated. The results are shown in Table 1 as workability A. In the workability A of Table 1, a mark with a mark Δ indicates that the molding defect was 5% or less and the baking to the mold did not occur, and a mark with a mark Δ indicated that the molding defect was 5 to 15% and the baking to the mold slightly occurred. Thing, ×
The sample indicated by the mark has a molding defect of 15% or more, and a large amount of baking to a mold has occurred.

Next, the above-mentioned sample was subjected to continuous press working without using press oil, and the defect of the molded product and the seizure to the die were evaluated. The results are shown in Table 1 as workability B. In the workability B of Table 1, a mark with a mark Δ indicates that the molding failure was 5% or less and the baking to the mold did not occur, and a mark with a mark Δ indicated that the molding failure was 5 to 15% and a little baking to the mold occurred. In addition, the samples marked with “x” have a molding defect of 15% or more and a lot of baking to the mold.

[Table 1] Sample type Lubricity Press workability A Press workability B Example 1 (non-porous film) 皮膜 〇 ２ Example 2 (non-porous film) 〇 〇 ３ Example 3 (microporous Film) 微 〇 〇 Example 4 (microporous film) 〇 〇 比較 Comparative Example 1 × 〇 × Comparative Example 2 × × × Comparative Example 3 △ 〇 △ Comparative Example 4 〇 〇 △

From the results shown in Table 1, the samples of Comparative Examples 1 to 4 have problems in lubricity and any of workability A and workability B, but the samples of Examples 1, 2, 3, and 4 have lubricity. It was found that both the press workability A and the press workability B passed. From this, Examples 1, 2, 3, 4
If the structure of the sample of, having a photocatalytic layer that can withstand plastic processing on an aluminum substrate or an aluminum alloy substrate,
It has been clarified that a uniform photocatalyst layer can be provided to an article subjected to plastic working.

Next, a photocatalyst paint ST- made by Ishihara Sangyo was applied to the plurality of substrates on which the underlayer used in Example 1 was formed.
K03 (trade name) with a coating amount of 0.15 g / m ² (0.09 μm film thickness), 0.30 g / m ² (0.18 μm film thickness),
0.60 g / m ² (0.36 μm thick)
Each sample was prepared by baking and drying at 250 ° C. for 30 seconds,
Each contact angle (°) was measured as an initial value. Contact angle meter CA manufactured by Kyowa Interface Science Co., Ltd.
-D was used. Subsequently, these samples were immersed in volatile oil RF-190 (trade name) manufactured by Showa Shell for 2 minutes and then dried, and the contact angle was measured in a state where the residual oil was present after drying.

Next, the dried substrate was irradiated with ultraviolet rays of about 1 mW / cm ² using a black light lamp (BBL lamp), and after 0.5 hour, 1 hour, 3 hours, and 6 hours. After 10 hours, after 24 hours,
After 48 hours, the respective contact angles were measured. The above results are shown in Table 2 below. In Table 2, “initial” indicates the contact angle before immersion in the volatile oil, and “oil contamination” indicates the contact angle after immersion in the volatile oil.

[Table 2] Oil contamination BBL lamp Irradiation amount of ultraviolet ray about 1 mW / cm ² Sample irradiation After initial value 0.5 1 3 6 10 24 48 1 0.15 g 22 82 83 87 75 46 19 25 6 2 0.30 g 22 84 81 88 50 20 5 65 3 0.60 g 25 84 83 86 35 11 10 10 5 5

From the results shown in Table 2, the thicker photocatalyst layer was obtained (the thickness of sample 1 was 0.09 μm, the thickness of sample 2 was 0.18 μm, and the thickness of sample 3 was 0.36 μm). It is clear that the ability to decompose residual oil and reduce the contact angle is improved. From the above, 0.09 μm to 0.3 μm
If the structure of the present invention is provided with a photocatalyst layer having a thickness of 6 μm, the contact angle can be significantly increased by irradiating ultraviolet rays for a relatively short time even in a state where the residual oil content after oil contamination and drying is present. It was clear that the contact angle after oil contamination could be reduced, and it was clear that the photocatalyst layer decomposed the residual oil of the organic matter, confirming that the photocatalytic function was generated. From this, it can be estimated that each photocatalyst layer can exhibit a purifying function (action) such as antibacterial and antifungal.

[0059]

As described above, according to the method of the present invention, a photocatalyst layer is formed on an aluminum or aluminum alloy substrate through a base layer of a nonporous anodic oxide film or a microporous anodic oxide film. Since the photocatalyst layer is provided, the photocatalyst layer can be provided on the aluminum or aluminum alloy substrate with good adhesion. In addition, by providing a lubrication layer on the photocatalyst layer, it is possible to have a structure that can withstand plastic working such as press working or extrusion working. If you leave
A molded article made of a photocatalyst precoat molding material having a photocatalyst layer uniformly provided on the entire surface after plastic working can be obtained. Furthermore, since the photocatalyst layer has a base layer of an anodized film, the photocatalyst layer laminated thereon has good adhesion, and can eliminate the influence of water or ions that evaporate or evaporate during the formation of the photocatalyst layer. Peeling and peeling can be prevented. If the molded article is obtained in this way, O ²⁺ or OH ⁻ can be generated by exciting electrons on the surface portion of the photocatalyst layer, which is exposed to light by contacting air over the entire surface of the molded article. The action of decomposing organic substances can be obtained by these actions. For this reason, a purification function (action) such as antibacterial and purification action can be obtained by the photocatalyst over the entire surface of the molded article.

As the photocatalyst layer, TiO_Two, ZnO,
SnO_Two, SrTiO_Three, WO_Three, Bi _TwoO_Three, Fe_TwoO_Threeof
Use one that is mainly selected from among
Ensures the photocatalytic purification function (action)
Can be obtained.

If a lubricating layer containing a nonionic polymer activator is used, press working, drawing work,
In the ironing process, seizure with the mold can be reliably prevented, molding can be performed without causing molding failure, and a molded product without peeling or falling off of the photocatalyst layer can be reliably obtained.

If a fin for an air conditioner heat exchanger or the like is formed by using the photocatalyst precoat molding material having the above-described structure, a heat exchange exhibiting an excellent purification action having uniform antibacterial and antifungal properties over the entire surface of the fin. Dexterous fins can be obtained. In addition, the fins for heat exchangers of the present invention are excellent in antibacterial properties and antifungal properties, and can provide favorable fins for recent hygiene booms and allergy countermeasures.

[Brief description of the drawings]

FIG. 1 is a sectional view showing the structure of a photocatalyst precoat molding material according to a first embodiment of the present invention.

FIG. 2 is a front view showing an example of a heat exchanger provided with fins made of a photocatalyst precoat molding material according to the present invention.

FIG. 3 is a model diagram showing a relationship between a film thickness and a porosity when an anodic oxide film is formed.

FIG. 4 is a model diagram showing a cross-sectional structure of a porous anodic oxide film.

FIG. 5 is a model diagram showing a cross-sectional structure of a microporous anodic oxide film.

[Explanation of symbols]

A: Photocatalyst precoat molding material, 1: Base material, 2: Underlayer, 3: Photocatalyst layer, 4: Lubricating layer, 10: Porous anodic oxide film, 10a ... -Barrier layer, 10b ... porous layer,
11 ... microporous anodized film, B ... heat exchanger, 14 ...
Fins (photocatalyst pre-coated molded products).

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Keitaro Yamaguchi 85-Hiramatsu, Susono-shi, Shizuoka Prefecture Mitsubishi Aluminum Corporation Technology Development Center F-term (reference) 4D048 AA21 AB03 BA07X BA07Y BA15Y BA16Y BA21Y BA22Y BA36Y BA41X BA41Y BB17 CC42 EA01 4G069 AA01 AA03 AA08 AA12 BA04A BA04B BA48A BB02A BB02B BB05A BB06A BC16A BC16B BC22A BC25A BC35A BC50A BC60A BC66A CA10 CA11 DA05 EA07 EB15X EB15Y EE04 EE06 FA04 FB23

Claims (10)

[Claims] 1. A metal substrate made of aluminum or an aluminum alloy, a base layer made of a nonporous anodic oxide film having a porosity of less than 5% formed on the surface of the metal base, and A photocatalyst precoat molding material, comprising: a formed photocatalyst layer. 2. A metal substrate made of aluminum or an aluminum alloy, an underlayer made of a microporous anodic oxide film having a porosity of 5 to 30% formed on the surface of the metal substrate, and And a photocatalyst layer formed on the photocatalyst precoat molding material. 3. The photocatalyst precoat molding material according to claim 1, further comprising a lubricating layer formed on the photocatalyst layer. 4. The photocatalytic layer is made of TiO ₂ , ZnO, Sn.
_{O 2, SrTiO 3, WO 3} , Bi 2 O 3, Fe 2 photocatalyst precoat molding material according to any one of claims 1 to 3 O ₃ of any one selected from among, characterized by comprising as a main body . 5. The photocatalyst precoat molding material according to claim 3, wherein the lubricating layer comprises a nonionic polymer activator. 6. The photocatalyst precoat molding material according to claim 5, wherein the thickness of the lubricating layer of the nonionic polymer activator is 0.02 μm or more. 7. A metal substrate made of aluminum or an aluminum alloy, a base layer made of a nonporous anodic oxide film having a porosity of less than 5% formed on the surface of the metal base, and A photocatalyst precoat molded article obtained by molding a photocatalyst precoat molding material comprising the formed photocatalyst layer and a lubricating layer formed on the photocatalyst layer. 8. A metal substrate made of aluminum or an aluminum alloy, a base layer made of a microporous anodized film having a porosity of 5 to 30% formed on the surface of the metal base, and A photocatalyst precoat molded product obtained by molding and processing a photocatalyst precoat molding material comprising a photocatalyst layer formed on a photocatalyst layer and a lubricating layer formed on the photocatalyst layer. 9. The photocatalyst precoated molded article according to claim 7, wherein the lubricating layer is removed after the molding. 10. A photocatalyst precoated fin obtained by molding the photocatalyst precoat molding material according to any one of claims 1 to 6.