JPH10158422A - Porous film and its production - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a porous film which exhibits homogeneous moisture- permeability and waferproofness because of its small variation in micropore size and which is low in cost. SOLUTION: A photosensitive permanent resist is applied in a thickness of about 10μm to a substrate (e.g. an aluminum foil) 10 with a bar coater and is baked under specified conditions to form a resist film 20. The resist film is closely covered with a photomask 30 having microporous pattern formed through it, is exposed to light, and is developed with a developing soln. exclusively used therefor. After the developed resist film is baked, it is peeled from the substrate or the substrate is dissolved and removed, giving a porous film 21 having many micropores 21a formed through it. Thus obtd. porous film has uniform-sized micropores, has homogeneous moisture permeability and waterproofness, and can be produced at a low cost since the production process is simple and the cost of production equipment is low.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a porous film functioning as a moisture-permeable waterproof membrane that blocks water droplets and allows water vapor to permeate, and a method for producing the same.

[0002]

2. Description of the Related Art A moisture-permeable waterproof membrane is used for clothing to block moisture such as raindrops from the outside and to transmit water vapor emitted from the human body. The diameter of the micropores formed in the film is in a range of 0.3 to 10 μm as a range in which water resistance can be obtained. Conventionally, various types of porous films functioning as moisture-permeable waterproof membranes of this type are known. For example, a porous film obtained by stretching an unfired polytetrafluoroethylene (PTFE) film, heating the film to form a large number of micropores, and laminating a porous film provided with the micropores. It has been known. Also,
A porous film is known in which a polymer is coated on the surface of a woven fabric, and then the polymer is coagulated in water to form micropores. Further, there is known a porous film obtained by forming a high-density woven fabric using a thin yarn having a single yarn denier of 1/5 to 1/10 as compared with a normal filament yarn, and performing a water-repellent treatment on the woven fabric. However, all of these porous films have a problem that the pore diameter of the micropores greatly varies, and it is difficult to obtain a uniform moisture-permeable and waterproof function, and the manufacturing process is long and expensive.

[0003] As another porous film, a film obtained by perforating a thin film with a laser is also known. However, this porous film has a problem that it is difficult to remove smears (work chips) adhered to the film surface by laser processing, and the cost of laser processing itself is high. An object of the present invention is to solve the above-mentioned problems, and an object of the present invention is to provide an inexpensive porous film and a method for producing the same, which can provide a uniform moisture-permeable and waterproof function with a small variation in the diameter of the fine pores. I do.

[0004]

Means for Solving the Problems and Effects of the Invention In order to achieve the above object, the structural feature of the invention according to claim 1 is that a thin film of a photosensitive permanent resist is formed on a thin film of a photosensitive permanent resist by photolithography. It is to provide a hole.

[0005] In the invention according to claim 1 configured as described above, since the fine holes are formed in the photosensitive permanent resist thin film by the photolithography technique, the porous film has fine holes having a uniform diameter. Therefore, it has a uniform moisture-permeable and waterproof function. Further, the diameter of the micropores can be freely changed according to the characteristics required for the porous film. Further, this porous film is obtained by forming micropores in a photosensitive permanent resist film by a photolithography technique, and is provided at a low cost.

Another feature of the invention according to claim 2 is that a photosensitive permanent resist film is applied and formed on a flat substrate surface, and a mask having a large number of fine hole patterns is formed on the photosensitive permanent resist film surface. Exposure in close contact, the fine hole pattern portion of the photosensitive permanent resist film is removed by development processing,
After the developed photosensitive permanent resist film is dried, it is removed from the substrate surface.

In the invention according to claim 2 configured as described above, in addition to the effects of the invention of claim 1, the manufacturing process is simple and the manufacturing equipment is inexpensive. Can be manufactured at low cost.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic diagram showing a manufacturing process of a porous film according to the embodiment. is there. First, a photosensitive permanent resist (for example, trade name, Multiposit XP-9500C manufactured by Shipley Co., Ltd.) is applied to the base material 10 (for example, a metal foil such as an aluminum foil that has been degreased).
C) is applied to a thickness of about 10 μm using a resist coating apparatus such as a bar coater or a roll coater, and baked at a predetermined condition, for example, at 90 ° C. for 30 minutes to obtain a resist film 20.
Is formed (FIG. 1A). Next, the resist film 20
A fine hole pattern (for example, a hole diameter of 5 μmφ, a pitch of 1
A photomask 30 having a thickness of 0 μm) is brought into close contact with the photomask 30 to perform exposure (FIG. 1B). The exposure is performed by, for example, irradiating ultraviolet rays 150 to 250 mJ / cm ² from a mercury lamp light source. The exposed resist film 20 is again baked under predetermined conditions, for example, at 90 ° C. for 15 minutes.

The baked resist film 20 is developed using a dedicated developer. As the special developer, a developer (product number XP-91254-4) manufactured by Shipley Co., Ltd. is used for Multiposit XP-9500CC. The development is desirably performed by a spray method in order to enhance uniformity, and is performed, for example, for 2 minutes using a developing solution at 35 ° C. The developed resist film 20 is baked again at 145 ° C. for 5 minutes after irradiation with ultraviolet light UV of 100 mJ / cm ² again under predetermined conditions, for example, over the entire surface. Thus, a porous film 21 having a large number of fine holes 21a is formed on the surface of the substrate 10 (FIG. 1C). Next, the porous film 21 is peeled from the base material 10 or the base material 10 itself is dissolved and removed to form a large number of fine holes 2.
1a is obtained, and the porous film 21 provided with
(D)).

As described above, according to the above embodiment, since the fine holes are formed in the thin film 20 of the photosensitive permanent resist by the photolithography technique, the porous film 21 has the fine holes having a uniform diameter. 21a,
Therefore, it has a uniform moisture-permeable and waterproof function. In addition, micropore 2
1a is manufactured by the photolithography technique, so that the fine holes 2a are formed in accordance with the characteristics required for the porous film 21.
The diameter of 1a can be freely changed. Furthermore, since the manufacturing process of the porous film 21 is simple and the manufacturing equipment is inexpensive, the porous film 21 can be manufactured at low cost.

The porous film 21 can be used as a moisture-permeable waterproof film, and can be applied to sportswear, sports shoes, raincoats and the like. In that case, in order to maintain the strength of the porous film, it is desirable to adhere a woven fabric to one or both surfaces thereof. The photosensitive permanent resist is a negative type resist, but a positive type resist can also be used.

[Brief description of the drawings]

FIG. 1 is a schematic view schematically showing a process for producing a porous film according to an embodiment of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 10 ... Base material, 20 ... Resist film, 21 ... Porous film, 21a ... Micropore, 30 ... Photomask.

Claims (2)

[Claims] 1. A porous film comprising a photosensitive permanent resist thin film provided with a large number of fine holes by photolithography. 2. A photosensitive permanent resist film is coated and formed on a flat substrate surface, and a mask having a large number of fine hole patterns is brought into close contact with the photosensitive permanent resist film surface and exposed to light. A method for producing a porous film, comprising: removing a fine hole pattern portion by a development treatment; drying the developed photosensitive permanent resist film; and removing the photosensitive permanent resist film from the substrate surface.