JP2000160360A - Hydrophilic metallic material and its production - Google Patents

Abstract

PROBLEM TO BE SOLVED: To produce a hydrophilic metallic material having a metallic oxide particle coating layer free from the coexistence of a binder or the like and small in the contact angle with water, and to provide a method for producing the same. SOLUTION: This hydrophilic metallic material is the one in which, on the surface of a base material metal, one or >= two kinds of metallic oxide particles selected from the groups consisting of TiO2, ZnO, SnO2, SrTiO3, WO3, Bi2O3 and Fe2O3 are buried. Furthermore, as for the method for producing the hydrophilic metallic material, a soln. contg. the metallic oxide particles is adhered to the surface of the base material metal, and after that, the obtd. base material metal is subjected to roll pressurizing and/or sliding with a member for sliding.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a hydrophilic metal material and a method for producing the same, and more particularly to a hydrophilic metal material having a small contact angle with water and a method for producing the same. INDUSTRIAL APPLICABILITY The hydrophilic metal material of the present invention can be suitably used as a metal material for preventing condensation of water droplets, which is required to prevent water droplets such as a ceiling inside a refrigerator.

Further, the hydrophilic metal material of the present invention can be suitably used as a metal material which is required to prevent the growth of water droplets, such as an exterior material which requires a beautiful appearance.

[0003]

2. Description of the Related Art Conventionally, water droplets may be formed on a metal surface of an inner wall of a kitchen refrigerator or the like. Bacteria and the like often propagate in these water droplets, and the water droplets adhere to, for example, the ceiling, grow, and drop into the food, etc.
It must not be hygienic.

[0004] For this reason, in the case where water drops are dripped, food is wrapped in a wrap or the like so that water drops are not directly applied. If a commercial refrigerator is taken as an example, if water drops do not drop from the ceiling, improvement in hygiene can be achieved, and it is not necessary to wrap the food in a wrap or the like, and the business process can be simplified.

In order to prevent water droplets from dropping, water droplets on the ceiling may be allowed to flow down the side walls in the refrigerator. In order for the water on the metal surface to flow down the sidewall without dripping,
A method has been considered in which the metal surface is made hydrophilic to reduce the contact angle with water.

Further, in order to prevent the exterior material of a building requiring a beautiful appearance from being stained, a method of making the exterior material surface hydrophilic has been studied. In order to prevent the water from dropping from the metal surface and allow the water droplets to flow down the side wall, the contact angle between the metal and the water only needs to be small,
As a method for imparting hydrophilicity for this purpose, there is a method of applying titania (titanium dioxide, TiO ₂ ) as a photocatalytic material to a metal surface.

[0007] Regarding the hydrophilizing treatment of the material to which anatase-type titania as a photocatalytic material is applied, a metal or a plastic material as a base material is converted from anatase-type titania as a photocatalytic material and silica (silicon dioxide, SiO ₂ ). A composite material has been developed in which an anatase-type titania on the surface of a film is hydrophilized by photoexcitation by ultraviolet irradiation using a material having a film formed thereon (see International Publication No. WO 96/29375).

One reason for using a silica-containing coating in the above-mentioned composite material is that silica plays a role of a binder for fixing anatase type titania which is a photocatalytic material. Not immobilized on the substrate. In other words, silica is indispensable for fixing titania to the base material, but there is a limit in adhesion to metal, and in order to cover, it is necessary to perform treatment such as high-temperature baking or ultraviolet irradiation, which is economical. Not preferred.

[0009] In addition, as a method of coating titania on the metal surface, a metal penetrating material of Ti and V is diffused and infiltrated into the surface of the base steel having a C content of 0.03 wt% or less. There is a method for producing steel for a denitration catalyst in which an oxidation treatment is performed under a temperature condition to form a composite oxide layer of Ti and V on the surface (see JP-A-5-168935). However, in this method, a heat treatment step of oxidizing metal Ti or the like is indispensable, and an oxide layer such as titania cannot be formed by a simple step.

[0010] Further, by using a film-coated metal or a coated metal as a substrate, a photocatalyst particle-containing suspension is applied on the substrate, or the substrate is immersed in the suspension. A method of fixing photocatalyst particles on the surface of a material and making the particles hydrophilic is disclosed (see JP-A-9-77535). In the case of the above-mentioned method, in order to fix the photocatalyst particles to the metal surface, it is essential to previously apply a film coat or a coating to the metal surface.

In the above-mentioned method, when a hydrophilic metal material is used as an exterior material of a building, it is difficult to maintain the effect of preventing contamination by a hydrophilic film for a long period of time. In addition, on the surface of substrates such as glass and plastic,
Silica, alumina, tin oxide, and TiO ₂ particles mixed with silicone in which at least a part of the organo groups bonded to the silicon atoms are substituted with hydroxyl groups are coated and heat-treated to fix and hydrophilize the photocatalyst particles. A method has been disclosed (see JP-A-9-78274).

However, in the case of the above method, it is necessary to mix a special silicone with titania or the like in order to maintain the adhesion of the film. A method in which a conductive material such as copper, silica or the like is coated as a first layer on a base material such as a metal, a stainless steel plate, or glass, and a photocatalyst such as TiO ₂ sol is applied as a second layer, followed by baking. (Japanese Unexamined Patent Publication No. 9-226041) or a method of coating and applying a Ti sol and fixing a hydroxyl group by ultraviolet irradiation or the like (Japanese Unexamined Patent Publication No. 9-2253).
No. 87).

However, in these methods, although the contact angle of the obtained surface with water becomes small, a binder such as silica is indispensable for fixing the photocatalyst in each method.
Problems such as oxidation and poor adhesion of the metal surface are caused by baking or irradiation with ultraviolet rays. JP-A-10-18082 and JP-A-10-18083 disclose a method of coating a base material with a colloid titanate anion, a Ti ⁴⁺ ion, and a TiO ₂ colloid by electrolysis.

However, these methods require an electrolysis step, and it is difficult to easily coat titania or the like. As described above, a metal material that can provide only a photocatalytic material, titania, in a simple process, and a metal material that can maintain the hydrophilicity of a metal surface for a long time are not known in the related art. I couldn't get it.

[0015]

SUMMARY OF THE INVENTION The present invention solves the above-mentioned problems of the prior art, and has a hydrophilic metal material having a metal oxide particle coating layer in which no binder or the like is mixed and having a small contact angle with water. It is another object of the present invention to provide a method for producing a hydrophilic metal material that can produce the hydrophilic metal material in a simple process.

[0016]

Means for Solving the Problems In order to solve the above-mentioned problems, the present inventors have studied and fixed experiments on a method for fixing metal oxide particles such as titania particles to the surface of a metal material. As a result, after the photocatalytic material such as titania particles is attached to the metal surface, the metal surface is pressed by a roll or the like without heating or by sliding the metal surface and the sliding member. It has been found that it is possible to obtain a hydrophilic metal material having a layer in which metal oxide particles in which a binder or the like is not mixed are embedded and having a very small contact angle with water.

That is, in the first invention, TiO ₂ , ZnO, SnO ₂ , SrTiO ₃ , WO ₃ , Bi ₂ O ₃ and Fe ₂
A hydrophilic metal material in which one or more metal oxide particles selected from the group consisting of ₂ O ₃ are embedded. In the above-mentioned first invention, it is preferable that the metal oxide particles are embedded to a depth of 1 μm or more from the surface of the base metal (a first preferred embodiment of the first invention).

Further, in the first invention and the first preferred embodiment of the first invention, the hydrophilic metal material is obtained by using metal oxide particles having an average particle diameter of 10 μm or less. It is preferably a metal material (the second preferred embodiment and the third preferred embodiment of the first invention). Further, in the first and third preferred aspects of the first invention and the first invention, it is preferable that the base metal is steel (first aspect).
Fourth to seventh preferred embodiments of the present invention).

Further, in the first and seventh preferred embodiments of the first invention and the first invention, the base metal is preferably a rolled steel plate (the first preferred embodiment of the first invention). Eighth preferred embodiment to fifteenth preferred embodiment). Further, in the eighth preferred embodiment to the fifteenth preferred embodiment of the first invention described above, it is preferable that the rolled steel sheet is a stainless steel sheet or a normal steel sheet having a carbon content of 0.02 wt% or less (first steel sheet).
Sixteenth to twenty-third preferred embodiments of the invention).

The hydrophilic metal materials according to the first invention and the first to twenty-third preferred embodiments of the first invention can be suitably used as a metal material for preventing condensation of water droplets. A second invention is to apply a solution containing metal oxide particles to the surface of the base metal, and then subject the obtained base metal to roll pressing and / or sliding with a sliding member. A method for producing a hydrophilic metal material characterized by the following.

In the second invention, the metal oxide particles are composed of TiO ₂ , ZnO, SnO ₂ , SrTiO ₃ , WO ₃ , Bi ₂ O
Is preferably one or more particles selected from ₃ the group consisting of Fe ₂ O ₃ (the first preferred embodiment of the second invention). In the second invention and the first preferred embodiment of the second invention, the metal oxide particles preferably have an average particle size of 10 μm or less (the second preferred embodiment of the second invention) Third preferred embodiment).

In the second and third preferred embodiments of the second invention and the second invention, the base metal is preferably steel (the fourth preferred embodiment of the second invention). Preferred embodiment to seventh preferred embodiment). Further, in the second preferred embodiment and the first preferred embodiment to the seventh preferred embodiment of the second invention, the base metal is preferably a rolled steel plate (the eighth preferred embodiment of the second invention). Aspect to fifteenth preferred aspect).

In the eighth to fifteenth preferred embodiments of the second invention, the rolled steel sheet preferably has an arithmetic mean roughness (Ra) ≦ 2 μm ( Sixteenth to twenty-third preferred embodiments of the second invention). In the eighth to twenty-third preferred embodiments of the second invention, the rolled steel sheet is more preferably a stainless steel sheet or a normal steel sheet having a carbon content of 0.02 wt% or less.

[0024]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in more detail. The hydrophilic metal material in the present invention is a hydrophilic metal material in which metal oxide particles are embedded in the surface of a base metal. In addition, the hydrophilic metal material in the present invention is defined as a metal material having a contact angle of 20 ° or less, more preferably 10 ° or less with water of the metal material.

As the base metal in the present invention, a plate-like material such as a rolled steel plate, a plated steel plate, an aluminum plate, a copper plate, a band-like material, or any other metal material of any shape can be used. As the rolled steel sheet, for example, a cold-rolled stainless steel sheet, a hot-rolled stainless steel sheet, a cold-rolled ordinary steel sheet, a hot-rolled ordinary steel sheet, or the like can be used.

As the coated steel sheet, a zinc-based alloy-coated steel sheet such as a zinc-coated steel sheet, a zinc-nickel-based alloy-coated steel sheet, a tin-plated steel sheet, a chrome-plated steel sheet, or the like can be used. As the base metal in the present invention, it is preferable to use steel from the viewpoint of corrosion resistance, strength, and economy, and for the same reason, stainless steel, carbon content of 0.02 wt
% Or less of ordinary steel is more preferable.

The base metal in the present invention includes:
It is preferable to use a rolled steel sheet. This is because, by using a rolled steel sheet as the base metal, the smoothness of the surface thereof causes the metal oxide particles to adhere, and then the steel sheet is roll-pressed and slides with the sliding member to thereby form the base metal. This is because it becomes possible to uniformly embed the metal oxide particles over the entire surface of the substrate.

Further, when a rolled steel sheet is used as the base metal, it is more preferable to use a rolled steel sheet having a surface roughness of arithmetic average roughness (Ra) ≦ 2 μm as the base metal for the reasons described above. . As metal oxide particles, Ti
It is preferable to use metal oxide particles composed of one or more selected from the group consisting of O ₂ , ZnO, SnO ₂ , SrTiO ₃ , WO ₃ , Bi ₂ O ₃ and Fe ₂ O ₃ .

Of these, TiO ₂ is harmless and chemically stable, and is most preferred. Also, as TiO ₂ ,
Any of anatase type, rutile type and amorphous can be used, but anatase type titania is preferably used as a main component since anatase type titania is more excellent in photocatalytic effect than rutile type titania.

Further, anatase type titania is preferable because it is relatively easy to obtain as a dispersion sol of very fine particles. Next, a method for embedding and fixing metal oxide particles on the surface of the base metal will be described. [Application of Metal Oxide Particle-Containing Solution to Base Metal:] That is, first, the surface of the base metal to which the metal oxide particles are adhered is sufficiently washed to remove dirt, and then applied to the surface of the base metal. A solution containing metal oxide particles is deposited.

The metal oxide particle-containing solution is a dispersion or a solution in which the oxide is dispersed in water or an organic solvent. The oxide is a sol, a gel, Alternatively, it may be an amorphous substance. In the present invention,
It is preferable to use a dispersion of metal oxide particles as the solution containing metal oxide particles.

As the solvent, water or an organic solvent can be used. The average particle size of the metal oxide particles in the metal oxide particle-containing solution is preferably 10 μm or less, more preferably 0.5 μm or less.
μm or less. The average particle size in the present invention is defined by the average value of the particle sizes measured by the line broadening method using the width of the diffracted X-ray.

In the case of amorphous oxide particles, it is measured by the Coulter counter method. By using the metal oxide particles having the above average particle diameter, the embedding of the metal oxide particles into the inside of the base metal surface layer by the pressing method and the sliding method in the present invention sufficiently proceeds.

The metal oxide particles are preferably embedded to a depth of 1 μm or more from the surface of the base metal. This is because if the embedding depth is less than 1 μm, the metal oxide particles are lost at an early stage due to wear or erosion of the surface of the base metal. The concentration of the metal oxide particles in the metal oxide particle-containing solution is 0.01 to 75% by weight.
Is preferred.

When the concentration is less than 0.01% by weight, the metal oxide particles are not sufficiently embedded and fixed on the metal surface, and sufficient hydrophilicity cannot be obtained. Conversely, when the concentration exceeds 75% by weight and the metal oxide particles excessively adhere to the surface of the base metal, coloring such as interference color occurs on the metal surface. As a method of applying the metal oxide particle-containing solution to the surface of the base metal and applying the solution, a spray method, an immersion method, a coater method, or the like can be used, and the application method is not particularly limited.

In the present invention, in order to reduce the contact angle of the metal material with water and to impart hydrophilicity, metal oxide particles adhere to the surface of the base metal in a solid content of at least 30 mg / m ² . Is preferred. This is because when the amount of the metal oxide particles attached is less than 30 mg / m ^2, it is difficult to reduce the contact angle of the obtained metal material with water to 10 ° or less.

Conversely, if the amount of metal oxide particles attached is excessive, hydrophilicity can be imparted, but coloring such as interference color occurs on the metal surface, so that the amount of metal oxide particles attached is 1500 mg / m 2.
^It is preferably ² or less. [Embedding of metal oxide particles on the surface of the base metal:] Next, the surface of the base metal to which the metal oxide particles have been applied and adhered is pressed by a roll or the like, or the metal oxide particles are applied. By sliding or sliding the surface of the adhered base metal and the sliding member, or further pressing or sliding, and pressing further, the metal oxide is formed on the surface layer of the base metal surface. Embed and fix the particles.

Although the pressing force is not limited,
kgf / mm ² or more, particularly a degree to which the base metal is slightly deformed is preferable. The appropriate set pressure depends on the type of metal oxide particles used and the depth at which the metal oxide particles are embedded. The pressurizing time is not particularly limited, and may be short (instantaneous).

The pressing means is not particularly limited. For example, skin pass rolling, shot blasting, draw bead processing, press, roll pressing, hydrostatic pressing, etc. can be used. It is suitable because it can be used without any change. The atmosphere at the time of pressurization is not particularly limited, and the pressurization can be performed in an air atmosphere.

After the pressure treatment, an oxide that has not been diffused (not embedded) may remain on the surface of the base metal, but this can be easily removed by washing with water. Since the metal oxide particles are embedded and fixed in the surface layer of the base metal, the oxide does not disappear or the adhesion amount does not significantly decrease when removing the metal oxide particles that are not diffused, and the hydrophilicity is reduced. Can maintain sex.

On the other hand, as a sliding method in which the surface of the base metal coated with the metal oxide particles is slid with a sliding member to embed the metal oxide particles in the base metal surface, a predetermined amount of the metal oxide particles is previously applied to the base metal surface. After applying the solution containing the metal oxide particles of the above and drying, the dried adhered surface is slid using a sliding member such as a polishing cloth such as a feather cloth or a polishing paper or a polishing belt to which abrasive powder is adhered. (: Polishing).

The metal oxide particle-containing solution to be applied in advance when embedding the metal oxide particles on the surface of the base metal by the sliding method is the same as in the case of the pressurizing method. It is preferable to use a dispersion liquid or a solution that is dissolved, and in the present invention,
More preferably, a dispersion of metal oxide particles is used as the metal oxide particle-containing solution.

This is because the use of a dispersion of metal oxide particles has the effect of improving poor contact with the metal surface caused by aggregation of the metal fine particles. As the metal oxide particles, a metal oxide in the form of a sol or gel can be used in addition to ordinary crystalline particles, or an amorphous metal oxide may be used.

The polishing powder used for polishing is preferably a powder of zirconia, diamond, alumina, silicon carbide or the like. Abrasive powder is fine powder with a particle size of 200 or more,
In particular, a polishing powder having a particle size such that a polished pattern having a design property is formed on the surface of the base metal is preferable. The polishing time is not particularly limited,
Short time (instant) is good.

Appropriate polishing conditions vary depending on the type of metal oxide particles used and the depth at which the metal oxide particles are embedded. The atmosphere at the time of sliding is not particularly limited, and the sliding can be performed in an air atmosphere. Regarding the hydrophilicity of the hydrophilic metal material, it is considered that the metal oxide particles exposed on the surface of the base metal exhibit hydrophilicity.

Therefore, according to the present invention, even if the surface of the base metal is worn or eroded, the metal oxide particles inside the embedded metal are newly exposed, so that the hydrophilicity does not decrease. In addition, no metal layer or alloy layer is formed on the surface of the metal material, and therefore, the properties of the surface of the metal material, such as the color tone, do not change. Further, it is preferable that the metal oxide particles are embedded in the surface of the base metal without being heated.

When the metal oxide particles are embedded without being heated, the metal oxide is not deteriorated and excellent hydrophilicity can be obtained. In addition, as described above, a roll pressing method can be used as the pressing method, and a polishing method can be used as the sliding method. Since the roll pressing method does not require any change to the existing rolling process, As the metal, a rolled plate of various metals such as a rolled steel plate is suitable.

In addition, by using a rolled plate, metal oxide particles can be uniformly embedded in the entire surface of the base metal.

[0049]

EXAMPLES The present invention will be described below more specifically based on examples. The arithmetic average roughness (Ra) of the base metal in the present example indicates the arithmetic average roughness (Ra) based on JIS B 0601-1994. The average particle diameter of the metal oxide particles is an average value (μm) of particle diameters measured five times by a line broadening method using diffracted X-rays.

The embedment depth of TiO ₂ from the outermost surface of the stainless steel sheet used as one type of the base metal is defined as the distribution of Ti in the depth direction in the following GDS (: glow discharge emission spectrometry) analysis. Based on the position of the intersection of the curve and the distribution curve of Fe in the depth direction, the Ti existing further in the depth direction
Is defined as the distance to the deepest part of (Example 1) As a base metal, the carbon content is 0.005wt%.
Arithmetic surface roughness (Ra) =
The surface roughness of 0.8 μm cold-rolled steel sheet and ferritic stainless steel is the arithmetic average roughness (Ra) = 0.4
Two kinds of μm cold-rolled steel sheets were used.

The titania-containing solution has an average particle size of 20 nm.
A water-based titania sol (solid content: 30 wt%) having a pH of 7 was applied to the surface of the base steel sheet using a roll coater, dried and adhered. In this example, an experiment was performed by changing the amount of attached titania (solid content) in the application of aqueous titania sol in the range of 10 to 2000 mg / m ² (Examples 1 to 18 of the present invention), and no titania was attached. A comparison was also made with the base steel sheet (Comparative Examples 1 and 2).

Next, a pressure of 10 kgf / mm ² (skin pass treatment with a rolling reduction of 1%) was applied to the obtained steel sheet to which the titania was adhered with a rolling roll at a temperature of 25 ° C. to thereby produce anatase-type titania. Was embedded in the surface layer of the surface of the base steel sheet and fixed. The metal material was washed with a neutral detergent to remove undiffused oxides to obtain a hydrophilic metal material.

The obtained metal material did not show any change in appearance even after washing with a neutral detergent. In addition, the state of embedding and fixing of titania in the surface layer of a hydrophilic metal material (Example 15 of the present invention) using a stainless steel plate as a base metal was investigated by GDS (: glow discharge optical emission spectrometer).

That is, the distribution (Ti, O) of titania in the depth direction from the surface of the hydrophilic metal material was analyzed by GDS. The results of the analysis are shown in FIG. As shown in FIG. 1, the presence of Ti was confirmed from the outermost surface of the obtained hydrophilic metal material to a depth of 3 μm.

Further, from the distribution of Ti, O, and Fe in the depth direction of FIG. 1, it can be seen that TiO ₂ is embedded in the stainless steel plate from the outermost surface of the stainless steel plate as the base metal to a depth of 2 μm. In addition, by SEM (scanning electron microscope), a hydrophilic metal material using a stainless steel sheet as a base metal (Example 1 of the present invention)
Observing the microstructure of 5), as shown in FIG.
It was confirmed that titania was present on the surface in the form of a film.

The portion where the scratch was made with the marking needle, the titania was peeled off, and the substrate was exposed is white. Further, as shown in FIG. 3, thin film X-ray diffraction of the hydrophilic metal material of Example 15 of the present invention confirmed that the titania adhered to and embedded in the base material was of the anatase type. Therefore, the hydrophilicity is not lost even by a little abrasion.

For comparison, FIG. 4 shows a depth direction analysis result by GDS method of a substrate (stainless steel plate) to which titania is not applied, and FIG. 5 shows a surface observation result by SEM. Next, the contact angle between the obtained metal material and water was measured, and the appearance of the metal material was evaluated.

The contact angle was measured under a 30 watt fluorescent lamp.
It was measured with a contact angle measuring device, and the appearance was evaluated by visual observation.
Table 1 shows the obtained performance test results.

[0059]

[Table 1] (Example 2) As a base metal, the carbon content is 0.010 wt%.
Arithmetic surface roughness (Ra) =
The surface roughness of cold rolled steel sheet of 1.2 μm and ferritic stainless steel is calculated as arithmetic average roughness (Ra) = 0.8
Two kinds of μm cold-rolled steel sheets were used.

The titania-containing solution has an average particle diameter of 20 nm.
A water-based titania sol (solid content: 30 wt%) having a pH of 7 was applied to a steel sheet surface using a roll coater, dried and adhered. In this example, experiments were carried out by changing the amount (solid content) of titania applied during the application of the aqueous titania sol in the range of 10 to 2000 mg / m ² (Examples 19 to 36 of the present invention). Was also compared with the base steel sheet (Comparative Examples 3 and 4) that did not adhere.

Next, the titania-adhering surface of the obtained steel sheet was polished using a feather cloth fixed with abrasive # 400 (silicon carbide) with an adhesive, and anatase-type titania was applied to the surface layer of the steel sheet surface. Embedded and fixed. This metal material,
Undiffused oxide was washed with a neutral detergent to obtain a hydrophilic metal material.

After that, the obtained metal material was washed with a neutral detergent, but no external change was observed. In addition, embedding of titania in the surface layer of a hydrophilic metal material (Example 31 of the present invention) based on a stainless steel plate,
The fixation situation was investigated by GDS. That is, the distribution (Ti, O) of titania in the depth direction from the surface of the hydrophilic metal material was analyzed by GDS.

FIG. 6 shows the results of the analysis. As shown in FIG. 6, from the outermost surface of the obtained hydrophilic metal material to a depth of 2 μm.
We confirmed the existence of Ti. In addition, the distribution of Ti, O, and Fe in the depth direction in FIG. 6 indicates that TiO ₂ is embedded in the steel plate from the outermost surface of the stainless steel plate as the base material to a depth of 1.7 μm.

When the microstructure of the hydrophilic metal material of Inventive Example 31 was observed by SEM, as shown in FIG.
It was found that titania (gray) was retained (distributed in islands) along scratches, cracks, and grain boundaries. As a result, it was found that the hydrophilicity of the hydrophilic metal material of the present invention did not disappear even if it was slightly worn.

Next, the contact angle between the obtained metal material and water was measured and the appearance of the metal material was evaluated. The contact angle was measured with a contact angle measuring device under a 30-watt fluorescent lamp.
The appearance was evaluated by visual observation. The obtained performance test results
It is shown in Table 2.

As is clear from Tables 1 and 2, by embedding and fixing anatase-type titania on the surface of the metal by pressure treatment or sliding treatment, the contact angle between the obtained metal material and water was 20 °. It was found that the hydrophilic metal material having a contact angle of 10 ° or less between the obtained metal material and water was obtained by setting the applied amount (solid content) of anatase type titania to 30 mg / m ² or more. .

[0067]

[Table 2] (Example 3) Instead of an anatase-type titania-containing sol,
Using aqueous tin oxide sol (average particle diameter of tin oxide: 10 nm) and aqueous strontium titanate sol (average particle diameter of strontium titanate: 20 nm), these sols containing metal oxide particles are used to apply metal to the base steel sheet. Oxide particle adhesion amount (solid content)
Was changed to 1000 mg / m ^2, and a hydrophilic metal material was obtained in the same manner as in Example 1 (Examples 37 to 40 of the present invention).

Next, in the same manner as in Example 1, the contact angle between the obtained metal material and water was measured and the appearance was evaluated. Table 3 shows the obtained performance test results. In addition, even if the obtained hydrophilic metal material was washed with a neutral detergent, there was no change in appearance.

[0069]

[Table 3] (Example 4) Instead of an anatase-type titania-containing sol,
Aqueous tin oxide sol (average particle diameter of tin oxide: 10 nm) and aqueous strontium titanate sol (average particle diameter of strontium titanate: 30 nm) are used. Oxide particle adhesion amount (solid content)
Was changed to 1000 mg / m ^2, and hydrophilic metal materials were obtained in the same manner as in Example 2 (Examples 41 to 44 of the present invention).

Next, in the same manner as in Example 1, the contact angle between the obtained metal material and water was measured and the appearance was evaluated. Table 4 shows the obtained performance test results. In addition, even if the obtained hydrophilic metal material was washed with a neutral detergent, there was no change in appearance.

[0071]

[Table 4] As is clear from Tables 3 and 4, tin oxide and strontium titanate are embedded and fixed on the surface of the metal by pressure treatment or sliding treatment, so that the contact angle between the obtained metal material and water is 10 °. It was found that the following hydrophilic metal materials were obtained.

Further, since the hydrophilic metal material of the present invention contains no binder, metal oxide particles such as titania, tin oxide and strontium titanate which impart hydrophilicity are exposed on almost the entire surface of the metal material. However, since the above-mentioned excellent hydrophilicity is obtained, and the oxide particles are embedded in the surface layer of the metal, it is possible to maintain the hydrophilicity even when subjected to abrasion. (Example 5) As a base metal, the carbon content is 0.015 wt%.
Arithmetic surface roughness (Ra) =
The surface roughness of 0.9 μm cold-rolled steel sheet and ferritic stainless steel is the arithmetic average roughness (Ra) = 0.6
Two kinds of μm cold-rolled steel sheets were used.

The titania-containing solution has an average particle diameter of 20 nm.
A water-based titania sol (solid content: 30 wt%) having a pH of 7 was applied to the surface of the base steel sheet using a roll coater, dried and adhered. The adhesion amount (solid content) of titania when applying the aqueous titania sol was 500 mg / m ² . Next, on the steel sheet to which the obtained titania was adhered, under the condition of a temperature of 25 ° C., 10 kgf /
A pressing force of mm ² (: skin pass treatment with a rolling reduction of 1%) was applied.

Next, the titania-adhered surface of the obtained steel sheet was polished using a feather cloth to which abrasive powder No. 400 (: silicon carbide) was fixed with an adhesive, and anatase-type titania was coated on the surface of the steel sheet. It was embedded in the part and fixed (Examples 45 and 46 of the present invention). These metal materials were washed with non-diffused oxides using a neutral detergent to obtain hydrophilic metal materials.

The obtained metal material did not show any change in appearance even after washing with a neutral detergent. Next, in the same manner as in Example 1, the contact angle between the obtained metal material and water was measured and the appearance was evaluated. Table 5 shows the obtained performance test results.

As shown in Table 5, a hydrophilic metal material having a contact angle of 10 ° or less between a metal material and water can be obtained by using both roll pressing and sliding by a sliding member. I understood.

[0077]

[Table 5]

[0078]

According to the present invention, it is possible to provide a hydrophilic metal material having a metal oxide particle coating layer in which a binder or the like is not mixed and having a small contact angle with water, and a method for producing the same. . Further, the hydrophilic metal material of the present invention has an excellent effect that the hydrophilic property can be maintained even if it is subjected to abrasion because the oxide particles are embedded in the surface layer of the metal.

[Brief description of the drawings]

FIG. 1 Ti, Fe, O, Cr in the depth direction of a hydrophilic metal material surface
5 is a graph showing the distribution of.

FIG. 2 is a scanning electron micrograph showing a metal structure on the surface of a hydrophilic metal material.

FIG. 3 is a graph showing a result of a thin film X-ray diffraction of a hydrophilic metal material.

FIG. 4 is a graph showing the distribution of Ti, Fe, O, and Cr in the depth direction on the surface of a base metal on which titania is not applied.

FIG. 5 is a scanning electron micrograph showing the metallographic structure of the surface of the base metal to which no titania is applied.

FIG. 6: Ti, Fe, O, Cr in the depth direction of the surface of a hydrophilic metal material
5 is a graph showing the distribution of.

FIG. 7 is a scanning electron micrograph showing a metal structure on the surface of a hydrophilic metal material.

Continuing from the front page (72) Inventor Yasushi Kato 1 Kawasaki-cho, Chuo-ku, Chiba City, Chiba Prefecture Inside the Technical Research Institute of Kawasaki Steel Corp. (72) Inventor Katsuhiro Nagayama 1-Kawasaki-cho, Chuo-ku, Chiba City, Chiba Prefecture F term in the company's technology research laboratory (reference) 4K020 AA22 AA26 AC01 AC04 AC07 BB28 4K044 AA02 AA03 BA12 BB11 CA23

Claims (2)

[Claims] 1. The method according to claim 1, wherein TiO ₂ , ZnO, SnO ₂ ,
A hydrophilic metal material in which one or more metal oxide particles selected from the group consisting of SrTiO ₃ , W 0 ₃ , Bi ₂ O ₃ and Fe ₂ O ₃ are embedded. 2. After adhering a solution containing metal oxide particles to the surface of the base metal, subjecting the obtained base metal to roll pressing and / or sliding with a sliding member. A method for producing a hydrophilic metal material.