JPH09141069A - Production of porous membrane by using anodically oxidized film of aluminum - Google Patents

Abstract

PROBLEM TO BE SOLVED: To largely increase mechanical strength and to easily produce a large- size separation membrane by filling a mesh-type titanium foil having lots of small holes with aluminum and anodically oxidizing the foil. SOLUTION: Spots 2 are formed by using a resist ink 3 by screen printing on a titanium foil 1 and the back surface is wholly coated. Then the foil is etched and the resist ink 3 is removed by using a solvent to form a porous foil 4. Then the porous foil 4 is filled with aluminum 6, titanium is vapor deposited on one surface, and the foil is further anodically oxidized to form a film 8 in the aluminum part. Then the foil is lightly etched to remove the vapor deposited titanium layer and the partitioning layers to obtain a composite film 9. Thus, a strong titanium foil and an aluminum anodically oxidized film are combined to obtain a composite membrane.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of applying an aluminum anodic oxide film having microscopic holes as a component separation film for liquids and gases.

[0002]

2. Description of the Related Art Aluminum anodic oxide coatings have a porous structure having several tens of billions of micropores with a diameter of 10 nm to 30 nm per square centimeter, depending on the type of electrolyte, so the coating is peeled off from the aluminum substrate and separated. Attempts have been made to use it for membranes and the like. However, the film has sufficient mechanical strength as long as it is in close contact with the substrate, but the peeled film is very brittle, so that the separation conditions such as pressure are largely restricted.

Further, since the peeling of the film is carried out by the reverse electrolysis method,
Damage during peeling is likely to occur, and it is difficult to peel off a large-area film.

[0004]

SUMMARY OF THE INVENTION According to the present invention, by combining a titanium foil, which is much tougher than a film, with an aluminum anodic oxide film to form a composite film, the mechanical strength is greatly increased and This makes it possible to easily form a separation membrane having an area.

[0005]

[Means for solving the problem] Diameter of titanium foil is 1.0 m
A large number of small holes of m or less are opened, aluminum is filled in the small holes, titanium is thinly vapor-deposited on one surface, and then anodization is applied from the opposite surface to form a film on the entire aluminum portion.

Further, the vapor-deposited titanium layer and the barrier layer at the bottom of the film are dissolved and removed to obtain a composite film having an anodized film through which microscopic holes penetrate in each small hole.

[0007]

Embodiments of the present invention will be described below with reference to the drawings.

As shown in FIG. 1, a resist ink 3 is screened so that spots 2 having a diameter of 0.7 mm are formed in a region of a diameter of 40 mm on one side of a titanium foil 1 having a thickness of 50 μm at a density of 64 spots per cm ^2. After applying by printing and further applying the entire back surface, etching is performed and the resist ink is removed with a solvent to obtain a porous foil 4.

Next, the small holes 5 of the porous foil 4 are filled with aluminum 6 by hot dip plating, and then one side is filled with about 0.6 μm.
Titanium 7 is evaporated to a thickness of.

Further, after the aluminum portion 6 is entirely formed into the film 8 by anodic oxidation, light etching is performed,
The vapor-deposited titanium layer 7 and the barrier layer are removed to form a composite film 9.

As shown in FIG. 2, the inner diameter 46 is increased for reinforcement.
The composite film 9 is sandwiched from both sides by a titanium ring 10 having a size of mm, an outer shape of 66 mm, and a thickness of 1 mm, and is fixed by spot welding 11. Here, the black dots of the composite film 9 in FIG. 2 are the anodized film 8, and the white parts are the titanium foil 1.

When the breaking pressure of this composite film was measured using nitrogen gas, it was about 0.2 MPa.

[0013]

EFFECTS OF THE INVENTION The breaking strength of an anodized aluminum film is determined by the type of electrolytic solution, electrolysis conditions, film thickness and area. Under the same electrolytic solution and electrolysis conditions, the film is thick and small in area. The higher the strength, the higher the strength. Since the present invention has a structure in which the film in the small holes is supported by a titanium foil which is much tougher than the film, the breaking strength of the separation film can be made equal to that of a film having an extremely small area.

Further, since the film is independent for each small hole, the breaking pressure can be increased regardless of the area of the entire composite film.

Further, even if the titanium foil is deformed, the stress exerted on the coating is small, so that it is possible to roll a rectangular composite membrane to form a cylinder.

The total area of the small holes effective for separation is about 3 cm ² in the case of the embodiment, but the film of the same area (about 20 mm diameter) by the conventional technique (reverse electrolytic stripping method) has It is so weak that it cannot be measured.

In the example, a titanium foil having a thickness of 50 μm was used and a small hole diameter of 0.7 mm was adopted. However, since the thickness of the film is almost the same as the thickness of the foil, a thicker foil is used.
By reducing the small hole diameter, it is possible to significantly increase the breaking pressure.

[Brief description of the drawings]

FIG. 1 is a process diagram showing a method of forming a membrane according to the first aspect of the present invention, which is a sectional view.

FIG. 2 is a plan view in which the membrane prepared in FIG. 1 is reinforced with a titanium ring.

[Explanation of symbols]

 1 Titanium foil 2 Spot 3 Resist ink 4 Porous foil 5 Small hole 6 Aluminum 7 Evaporated titanium 8 Anodized film 9 Composite film 10 Titanium ring 11 Spot welding

Claims (1)

[Claims] 1. A mesh-shaped titanium and its alloy, or tantalum and its alloy foil or plate having a large number of small holes is filled with aluminum by means such as plating, vapor deposition, and powder filling, and then anodized. Characteristic membrane production method.