JPH09155972A - Water repellant film and its manufacture - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make it possible to obtain the excellent water repellency without using a water repellant by providing many convergent fine protrusions or many fine fibrous surface layers on the surface of a film. SOLUTION: Many fine protrusions or many fine fibrous surface layers are provided on the surface of a film made of a polyolefin, a halogen-containing polyolefin, a polyester or a polyamide. This film can be manufactured by transferring the surface shape from a mold material having convergent protrusions on the surface to the film. The mold is obtained by adodizing or dissolving an aluminum material and forming an alumite film having convergent fine protrusions on the surface. The shape of the protrusion is preferably a stylus state by generally considering the strength and water repellency. Thus, the excellent water repellency can be obtained without the film of a water repellant.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a film having water repellency and oil repellency, and by applying this to other members, a water repellent surface can be provided.

[0002]

2. Description of the Related Art Conventionally, as a water-repellent material, Japanese Patent Laid-Open No. 3-10
The aluminum material described in Japanese Patent No. 0182 is known. It is said that the surface is an alumite film, which is coated with a water repellent such as a fluorine-containing silane compound, and the surface contact angle with respect to water droplets is 120 ° or more.

However, since this is a method of treating the surface of an aluminum material, its field of use is naturally limited, and when it is difficult to perform necessary treatment for imparting water repellency to some parts. There is also. In addition, in order to obtain water repellency, coating with a water repellent is essential, but the water repellency that can be achieved by this method is still insufficient, and depending on the type of water repellent used, the water attached to the water repellent surface There is also a problem that it does not reach the point where it falls into water drops and falls. Also, a polytetrafluoroethylene film is known as a film-like water-repellent material. But,
This film is expensive and has a surface contact angle of 93 ° with respect to water drops, which is not enough for the water drops to roll down the surface.

[0004]

Therefore, the present invention can be widely and easily applied to various fields, shows excellent water repellency and oil repellency regardless of the coating of the water repellent, and is inexpensive and general. It is an object of the present invention to provide a water-repellent film which can be used as a film material and a method for producing the same.

[0005]

Means for Solving the Problems As a result of intensive studies, the present inventor has found that remarkable water repellency can be obtained by forming a large number of projections with thin tips on the surface layer of a film which is in contact with water droplets. However, it is also found that such a surface layer can be formed by transferring a surface fine pattern formed by a dissolution treatment of a mold material capable of molding corresponding protrusions such as an anodized film of an aluminum material to a film, The present invention has been completed.

That is, the present invention provides (1) a water-repellent film characterized in that it has a large number of tapered fine protrusions on the surface of the film, or has a large number of fine fibrous surface layers. 2) The water-repellent film according to (1) above, wherein the film is a polyolefin, a halogen-containing polyolefin, a polyester, or a polyamide, and (3) a film having a surface shape obtained from a mold having a large number of tapered fine protrusions or fine holes. A method for producing a water-repellent film, wherein (4) the mold having the protrusions or the fine holes is subjected to anodizing treatment and dissolution treatment on an aluminum material,
The alumite film having a large number of tapered fine protrusions or fine holes is formed on the surface thereof (3)
(5) The method for producing a water-repellent film according to (5), wherein the mold having the protrusions or fine holes is subjected to anodizing treatment or dissolution treatment on an aluminum material, and the surface thereof has a number of fine protrusions or fine taper Form an alumite film with various holes,
Then, the method for producing a water-repellent film according to (3), which is a transfer mold formed from this, (6) the mold imparts conductivity to the surface of the alumite film having a large number of tapered fine protrusions, The method for producing a water-repellent film according to (5) above, which is a reversal type formed by plating this and peeling the plated portion from the alumite coating.
The method for producing a water-repellent film according to (6), wherein the plating part is peeled off by dissolving the alumite film, and (8) an insulating layer between the alumite film and the aluminum material for imparting conductivity to the surface of the alumite film. The method for producing a water-repellent film according to (6) above, which comprises:

It is important that the water-repellent film of the present invention has a large number of fine projections having a tapered shape on the surface or has a fine fibrous surface layer.

From the viewpoint of the strength of the water repellent surface, it is preferable that the cross section has a shape that decreases toward the surface, that is, a projecting portion having a thick root and a thin tip. Specific shapes of the protrusions in the present invention include a pointed shape, a needle shape, a pointed ridge shape, and a shape in which these are combined, but strength,
In consideration of water repellency and die cutting, it is most preferable that the shape is needle-like.

Further, a fibrous surface in which the needle-like shape is further thin, or a feather-like surface in which the fibrous protrusions are intricately intertwined may be used.

The water-repellent film of the present invention can be manufactured by transferring the surface shape of a mold material having fine tapered fine protrusions or fine holes on the surface thereof to the film. The fine holes preferably have a tapered inner side.

The mold material is an aluminum material which is anodized to form a porous alumite film on its surface.
Further, a large number of enlarged fine holes are formed on the surface layer by the dissolution treatment of the fine pores (first type), and a sharp ridge formed by further expanding the fine pores by the dissolution treatment. There is a shape (second type). As the aluminum material, aluminum or its alloy material can be used.

As a mold material for producing a water-repellent film, the surface of an alumite film having needle-like protrusions is formed by anodizing and dissolving the aluminum material, and the surface is further electroplated. It is also preferable to use an inversion type (negative) (third type) formed by. The third mold has holes that taper inwardly on the surface, and a film having the same needle-like protrusion surface as the alumite coating surface can be obtained from such mold material.

The water-repellent film can be formed by transferring the fine shape of the mold material by pressing the film on the mold material under heating. It can also be formed by extruding a thermoplastic resin into a mold material. Further, a solution of the film material can be poured into the mold material to mold it. When molding such a film, while the mold material has a needle-like structure due to the internal structure of the mold material and the viscosity of the film material to which it is transferred, the above-mentioned many fibers are entangled in the film to which it is transferred. Such a feathery surface may be formed.

The film material for transferring the fine protrusions is not particularly limited, but a plastic film is preferable. Examples of such plastic films include polyolefins such as polyethylene, polypropylene and polybutylene, halogenated polyolefins such as polyvinyl chloride and polytetrafluoroethylene, polyesters and poamides.

The water-repellent film of the present invention is superior in water repellency to polytetrafluoroethylene, which has been well known as a water-repellent material. Further, the film of the present invention using polytetrafluoroethylene exhibits remarkably excellent water repellency as compared with the polytetrafluoroethylene itself having no surface shape of the present invention.

As described above, the water-repellent film of the present invention is
Since it has excellent water repellency by itself due to the special fine structure of its surface layer, it is not necessary to separately coat it with a water repellent. However, the film of the present invention can be further coated with a water repellent. Next, the method for producing the water-repellent film of the present invention will be further described.

As described above, the water-repellent film of the present invention can be produced by transferring a pattern having a large number of fine tapered projections onto the film. As a first method of manufacturing the transfer mold material, a method of utilizing anodizing treatment and dissolution treatment of an aluminum material can be mentioned.

1A to 1C are explanatory views schematically showing the method of forming the first mold. Figure 1A shows Al material before treatment, B
Indicates a state in which aluminum is anodized and a porous alumite coating is formed on the surface thereof, and C indicates a state in which the alumite coating is dissolved and the surface pores are enlarged in a tapered shape. Further, FIG. 1D shows a state (the second mold) in which the fine dissolution is formed in a thin ridge shape (pointed ridge shape) by further progress of the dissolution treatment.

The conditions of the anodizing treatment are not particularly limited, and for example, ordinary treatment conditions can be adopted in a solution containing sulfuric acid, oxalic acid or phosphoric acid. Then
The porous alumite film is subjected to a dissolution treatment. The dissolution treatment is performed with a solution containing, for example, phosphoric acid, sulfuric acid, and sodium hydroxide, but the dissolution treatment can be performed simultaneously with the anodization treatment.

By using the first and second molds produced as described above as transfer molds, a resin film is pressed against this, softened and melted, and the solidified product is peeled from the mold. The water-repellent film of the present invention can be manufactured.
The method for heating the film is preferably by heating the mold. The water-repellent film can also copy the uneven surface of the mold cleanly, but as shown schematically in FIG. 2, after peeling due to the fine structure of the protruding portion or the viscosity of the resin material,
A large number of fibrous materials may become a fluffy surface intertwined with each other.

A second method of forming a mold material for producing the water-repellent film of the present invention is schematically shown in FIG. FIG. 4 is a schematic illustration of the enlargement treatment of the pores (pores) by the anodizing treatment and the dissolving treatment among these.
A is an Al material before treatment, B is a state in which aluminum is anodized and a porous alumite coating is formed on the surface, C is a dissolution treatment of the alumite coating, the pores on the surface expand and cracks occur. However, D indicates a state in which a tapered protrusion is formed on the surface, and D indicates a state in which the dissolution process further progresses and the protrusion is formed in a needle shape or a needle mountain range shape. The aspects of the anodic oxidation treatment and the dissolution treatment are basically the same as described above. In particular, when forming dense and independent needle-shaped protrusions, it is preferable that the anodic oxidation treatment is sequentially performed in a sulfuric acid solution and the dissolution treatment is sequentially performed in a phosphoric acid solution. When processed in this way, the root is 1 to 10 μm and the height is 1 to 30.
μm, the density is 1 to 100 per 100 square microns
An independent needle-like protrusion of the book is obtained. The aluminum material is anodized and dissolved to form only needle-shaped or mountain-shaped protrusions on the surface of the anodized film, and then preferably an insulating part (barrier layer) is formed between the aluminum base material and the anodized film. ) Is formed. This is performed by a usual barrier layer forming method. The insulating part is formed in the next step by giving conductivity only to the anodic oxide film, and when molding (electroforming) the transfer mold by the plating technique, the adhesion of the plating is good and the aluminum base material is electrically charged. It is important to prevent it from flowing.

After forming the insulating portion (barrier layer), conductivity is imparted to the surface of the anodic oxide film by vapor deposition or electroless plating. Further, a material serving as a transfer mold is formed on the conductive film by electrolytic plating or the like. Furthermore, the transfer mold formed on the surface of the aluminum material is peeled off between the aluminum base material and the anodized film, and then the anodized film is dipped in a solution similar to the above-described dissolution treatment to leave only the film. By melting and melting, a transfer mold material having tapered holes is formed toward a large number of aluminum material surfaces corresponding to the protrusions formed on the aluminum material surface. Therefore, the material of the mold needs to be one that does not dissolve in the dissolution treatment. As for the obtained transfer mold, the water-repellent film of the present invention can be manufactured by pressing the film against a heated mold and peeling the solidified product from the mold, as in the first manufacturing method.

Compared with the first manufacturing method, the water-repellent film can cleanly copy the uneven surface of the mold, and it is easy to obtain a large number of independent needle-shaped protrusions. However, as in the first manufacturing method, a large number of fibrous materials may be entwined to form a feathery surface. Also, as the mold, the first
It is possible to provide a mold having a longer life than the mold using the anodic oxide film of the manufacturing method of.

[0024]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be specifically described based on the following examples.

Example 1 An aluminum plate was subjected to 1 A in a 10% sulfuric acid aqueous solution at 20 ° C.
Anodizing treatment was performed for 1 hour at a current density of / dm ² . Next, the aluminum plate was immersed in a 5% phosphoric acid aqueous solution at 50 ° C. and subjected to a dissolution treatment for 12 minutes to form a surface layer having a large number of needle-shaped fine protrusions. 0.5 A / d was applied to the obtained aluminum material in a 0.3% phosphoric acid aqueous solution at 20 ° C.
The insulating portion formation treatment was performed at a current density of m ² for 5 minutes to form an insulating portion (barrier layer).

Next, gold is coated on the surface of the anodic oxide film by a sputtering method to impart conductivity to the anodic oxide film, and the gold is applied at a current density of 5 A / dm ² in a 50 ° C. watt bath.
Nickel plating was performed for a time to mold a transfer mold.

A transfer mold formed on the surface of an aluminum material was peeled off between the aluminum base material and the insulating part and subjected to solution treatment in a 10% sodium hydroxide aqueous solution at 50 ° C. for 10 minutes, The anodized film was melted away and only the transfer mold was used. The resin film shown in Table 1 was pressed under heating to the obtained transfer mold, and the solidified product was released from the mold to produce a water-repellent film.

Next, the contact angle of the obtained film with water was examined. Data for untransferred films were also measured for comparison. Further, SEM images of transfer surfaces of nickel type, PE, PET and PVC are shown in FIGS. Table 1 shows the results.

Table 1 Type of film PE PET PVC Teflon No transfer (Comparative example) 86 ° 87 ° 89 ° 93 ° Transfer film (Example of the present invention) 145 ° 149 ° 100 ° 128 ° Note PE: Polyethylene PET: Polyethylene terephthalate PVC : Polyvinyl chloride Teflon: Polytetrafluoroethylene

From Table 1, it can be seen that the inventive examples have excellent water repellency as compared with the comparative examples. Especially, the contact angle of polyethylene and polyethylene terephthalate is 140 °.
As described above, the water droplets fell off the surface.

Example 2 0.5 ° C. on an aluminum plate in a 3% phosphoric acid aqueous solution at 20 ° C.
Anodizing at a current density of A / dm ² for 20 minutes,
Next, the aluminum material was immersed in a 5% phosphoric acid aqueous solution at 50 ° C. and subjected to a dissolution treatment for 12 minutes to obtain an aluminum material having an anodized film having tapered holes facing a large number of aluminum plates formed on an aluminum base material. .

Using the obtained aluminum material as a transfer mold, the resin films shown in Table 2 were pressed under heating, and the solidified product was released to produce a water repellent film. The film obtained in the same manner as in Example 1 was examined for the contact angle with water. Table 2 shows the results. Also, the SEM of the surface of the aluminum mold, PE transferred from the aluminum mold, and PET.
Images are shown in FIGS.

Table 2 Type of film PE PET transfer film (Example of the present invention) 138 ° 136 °

From Table 2, it can be seen that the examples of the present invention have superior water repellency to the comparative examples shown in Table 1. Also,
Although the water repellency is inferior to that of Example 1, it can be seen that a film having high water repellency can be easily produced.

[0035]

Industrial Applicability The water-repellent film of the present invention can exhibit excellent water repellency regardless of the use of the water-repellent agent, and a general relatively inexpensive resin film can be used as the film. is there. Then, this film can be used to impart water repellency to other members by adhering it, which is useful in a wide range of fields.

[Brief description of the drawings]

FIG. 1 schematically illustrates a process of forming first and second molds used in the method for producing a water-repellent film of the present invention, in which A is an untreated Al material and B is anodized aluminum. Then, a state in which a porous alumite film is formed on the surface, C is a state in which the alumite film is subjected to a dissolution treatment and the pores on the surface are tapered and expanded (first type), and D is an explanatory view of the second type. Shows the state in which the dissolution process further progressed and the protruding portions were formed into thin ridges.

FIG. 2 is a diagram schematically illustrating a pattern in which a fine fibrous surface is formed when the film is pressed and transferred to a mold having fine tapered holes in the production of the water-repellent film of the present invention. .

FIG. 3 is a third part used in the production of the water-repellent film of the present invention.
FIG. 5 is a diagram schematically illustrating an example of a manufacturing process of the transfer mold of FIG.

FIG. 4 is a schematic illustration of a process for forming a third mold used in the method for producing a water-repellent film of the present invention, in which pore enlargement treatment by anodizing treatment and dissolution treatment is performed. Al material, B is a state in which aluminum is anodized and a porous alumite film is formed on the surface, C is a solution of the alumite film, the pores on the surface are enlarged, and tapered protrusions are formed on the surface. The formed state, D, shows the state in which the melting process further progresses and the protrusions are formed in a needle shape and a mountain range shape.

5 is an SEM image of the surface of the nickel transfer mold used in Example 1. FIG.

6 is a surface SEM image of the water-repellent polyethylene film obtained in Example 1. FIG.

FIG. 7 is a surface SEM image of the water-repellent polyethylene terephthalate film.

FIG. 8 is a surface SEM image of the water-repellent PVC film.

9 is an SEM image of the surface of the aluminum transfer mold used in Example 2. FIG.

FIG. 10 is an SEM image of the same section.

11 is a surface SEM image of the water-repellent polyethylene film obtained in Example 2. FIG.

FIG. 12 is a surface SEM image of the water-repellent polyethylene terephthalate film.

Continuation of front page (51) Int.Cl. ⁶ Identification code Office reference number FI technical display location // B29L 7:00

Claims (8)

[Claims] 1. A water-repellent film having a large number of tapered fine protrusions or a large number of fine fibrous surface layers on the surface of the film. 2. The water-repellent film according to claim 1, wherein the film is a polyolefin, a halogen-containing polyolefin, a polyester or a polyamide. 3. A method for producing a water-repellent film, which comprises transferring the surface shape of the mold to a film from a mold having a large number of tapered fine protrusions or fine holes. 4. A mold having the protrusions or fine holes,
The method for producing a water-repellent film according to claim 3, wherein the aluminum material is subjected to anodizing treatment and dissolution treatment, and an alumite coating having a large number of tapered fine protrusions or fine holes is formed on the surface thereof. 5. A mold having the protrusions or fine holes,
4. A transfer mold formed by subjecting an aluminum material to anodization treatment and dissolution treatment to form an alumite coating film having a number of tapered fine protrusions or fine holes on the surface thereof, and then molding this. Method for producing water-repellent film. 6. A reversal formed by imparting conductivity to a surface of an alumite coating having a number of fine protrusions of a taper shape, plating this, and peeling the plated portion from the alumite coating. The method for producing a water-repellent film according to claim 5, which is a mold. 7. The method for producing a water-repellent film according to claim 6, wherein the plating part is peeled off by dissolving the alumite film. 8. The method for producing a water-repellent film according to claim 6, wherein an insulating layer is formed between the alumite coating and the aluminum material in order to impart conductivity to the surface of the alumite coating.