JPS646281Y2 - - Google Patents

Description

[Detailed description of the invention] The present invention places an intermediate heat-absorbing layer containing a hygroscopic base material between two membrane-like materials having micropores that allow water vapor particles to pass through but do not allow raindrops to pass through. Regarding an integrated waterproof sheet.

Conventionally, raincoats and waterproof clothing have been formed by covering the back of the fabric with a film of synthetic resin such as rubber, vinyl chloride, or acrylic. And although these things could prevent raindrops from outside,
A major drawback was that sweat accumulated on the inside, causing it to get wet and stuffy. Also, attempts were made to cover the surface of the fabric with these waterproof membranes, but almost the same problem occurred.

Recently, in order to provide products that are in high demand such as sports clothing such as jackets, personal items such as raincoats, and outdoor equipment such as tents, it has completely rainproof properties and eliminates sweat, moisture, etc. that accumulate inside. There is a strong demand for a waterproof sheet that eliminates stuffiness by quickly releasing it to the outside.

Theoretically, it is not so difficult to achieve both rainproofness and perspiration release properties in these tarpaulin sheets. In other words, the diameter of water vapor particles is about 3/10 millionths of a millimeter, while the diameter of raindrops is about 1 mm even if it is just a drizzle, so if the waterproof fabric has many holes with diameters in between, the water vapor particles will be smaller. This is because even if it passes through, it is possible to prevent raindrops.

Focusing on this, we have recently developed (i) stretched polytetrafluoroethylene resin under special conditions to create a film with countless small holes in the shape of a spider's web, and the size of the holes to be about 2/10,000 mm; (approximately 700 times the size of a water vapor molecule, approximately 1/5000 times the size of a raindrop), thickness
Waterproof and permeable wetlands made by laminating fabrics with a thickness of about 2.5 mm have been developed and are commercially available.

(ii) Also, a special film layer of polyurethane is formed on the surface of the fabric, which is created by creating countless small holes in the undried polyurethane layer and then drying it. The diameter of the surface of the pores is between 0.5mm and 3/1000ths of a millimeter, but there are even larger pores inside that are formed like a sponge, allowing the water vapor from sweat to pass through the pores and be released to the outside. ing.

Waterproofing and moisture permeability based on the above two methods have been developed and announced, but the current situation is that when these are put into practical use, the phenomenon of stuffiness still remains unsolved. The reason for this is that, theoretically, "stuffiness" should not occur, but when it rains, the surface of the membrane is water repellent or waterproof, so raindrops do not penetrate into the inside of the membrane. Since the membrane is uniformly wetted and the pores are temporarily sealed by rainwater, the diffusion of water vapor that evaporates from the inside of the membrane to the outside is blocked, thus eliminating "stuffiness". It's something that doesn't exist.

The present invention has been developed in order to improve the waterproof and permeable wetlands after thorough consideration. That is, the waterproof sheet according to the present invention is made of a high-molecular polymer material, and is arranged between two membrane-like materials that transmit water vapor particles but not raindrops, and a membrane-like material that is arranged between these two membrane-like materials. It is formed by integrating an intermediate hygroscopic layer containing a hygroscopic base material.

The present invention will be described below based on embodiments with reference to the drawings.

FIG. 1 is a schematic explanatory diagram showing a cross section of a waterproof sheet according to the present invention.

The waterproof sheet 10 has a first film-like material 11 and a second film-like material 12, each of which is made of a high-molecular polymer material and has countless micropores 13 and 14 that allow water vapor particles to pass through but not raindrops to pass through. An intermediate hygroscopic layer 15 containing a hygroscopic base material is placed between two membrane-like materials, and these are integrated. In this case, the first
Micropores 13 of each of the film-like material 11 and the second film-like material 12,
It is preferable that the average diameters of 14 are approximately equal.

Any known method other than the above-mentioned method can also be used to form such a film-like material. Also,
Film thickness is usually 0.005mm (5μ) to 1mm (1,000μ)
It is applicable within the range of, but it is particularly preferable that
It is 0.01mm (10μ) to 0.5mm (500μ). In addition, other synthetic resins such as PVC, polyolefin resins such as PP and PE, including fluorine compound resins and polyurethane resins, can be used as materials for the polymers that form the membrane.
There is no particular limitation on the type as long as it satisfies the above requirements. However, from the viewpoint of rainproofing, it is preferable that the material be hydrophobic, preferably water repellent.

Next, the hygroscopic base material interposed between the membranes, which is an important component of the present invention, will be explained. This material is preferably a cellulose-like material having hygroscopic properties, such as cellulose fiber. Other natural fibers such as wool are also preferred. Furthermore, its form is
Examples include knitted fabrics, non-woven fabrics, paper, paper cotton, etc., and in some cases, powdered materials may be used. However, when the intermediate hygroscopic layer is arranged in a sandwich pattern between the first and second membranes and integrated, the distribution of the material forming the intermediate hygroscopic layer is uniform so that the adhesion strength of these three layers is sufficient. It is desirable that the material is or is distributed with a predetermined directionality. moreover,
The intermediate moisture-absorbing layer may include, for example, a hydrophobic base material containing a water-absorbing group inside. In this case, cellulose fibers, wool, etc. are used as the water-absorbing base material. In addition, water-absorbing resins can also be used in special cases. Specifically, polybutylene-maleic anhydride copolymer, pulp materials, cellulose derivatives,
Sodium polyacrylate, polyethylene oxide, polyvinylpyrrolidone, sulfonic acid, etc. are effective. Furthermore, when considering the durability of these water-absorbing base materials, water-insoluble and hydrophilic ones are preferable.For this reason, it is preferable to use water-insoluble and hydrophilic materials. Various substitution-modified substances are used, such as crosslinked polyethylene oxide, polyvinyl pyrrolidone, sulfonated polyethylene, sodium polyacrylate, cellulose transparent conductor, oxidation of polyacrylonitrile or starch-acrylonitrile graft copolymer. Natural or synthetic materials such as natural substances are preferable.

Next, the integration of the above three layers will be explained. For integration, it is common to use an adhesive to adhere them to each other in dots or lines. All known adhesives can be used, but it is desirable that the bonding area be as small as possible in order to leave as much micropores as possible.
In order to integrate, other known means such as fusing and sewing can be used.

In the waterproof sheet thus obtained, even if raindrops adhere to the outer surface, they will not be able to pass through the first membrane, and will be water-repelled by the outer surface having hydrophobic and water-repellent properties. At this time, some of the raindrops that collide with the outer surface may become a thin water film that closes the pores of the first membrane and blocks the dispersion of moisture from the inside to the outer surface, but the waterproof sheet of the present invention In this case, the moisture inside that causes stuffiness passes through the second film-like material and transfers to the hygroscopic base material, where it adheres or temporarily remains. When the above-mentioned thin water film dries and disappears, the absorbed moisture can permeate the pores of the first membrane material from the hygroscopic base material and diffuse to the outside.

In this way, even if the pores of the first film-like material are temporarily covered with water droplets, the internal moisture passes through the second film-like material and is adsorbed by the hygroscopic base material. The retention of moisture on the inner side is significantly reduced, and the phenomenon of "stuffiness" is almost completely eliminated. In other words, in the case of the product of the present invention, when it rains,
It dehumidifies continuously from the inside to the outside regardless of whether the weather is sunny or not, and its effectiveness in preventing stuffiness is far superior compared to any other waterproof sheet.

In the waterproof sheet according to the present invention, the first film-like material is often directly exposed to the atmosphere for the purpose of water repellency, but it may be covered with another material during use, if necessary. In addition, the outer surface of the second membrane, that is, the side closer to the body, etc., may be covered with a highly breathable knitted fabric, nonwoven fabric, paper, or other material within a range that does not impair the inherent moisture permeability of the second membrane. This may enhance the aesthetic appearance and wearability.

As described above, the waterproof sheet of the present invention consists of two membrane-like materials having a large number of micropores that allow water vapor particles to pass through but not raindrops, and a hygroscopic material placed between these two membrane-like materials. Even if the micropores of the first film-like material exposed to the outer surface are sealed with a water film, the water vapor inside is continuously adsorbed or temporarily retained on the hygroscopic substrate through the micropores of the second membrane, and after the water film on the outer surface is dissolved, it quickly passes through the second membrane to the outside. can be transpired into Furthermore, during sunny weather, the moisture that has passed through the pores of the second membrane quickly passes through the hygroscopic base material and is radiated to the outside from the pores of the first membrane. in this way,
To prevent stuffiness from occurring inside the waterproof sheet whether it is raining or sunny. Furthermore, when the average diameters of the pores in the two membranes are approximately equal, the same type of membrane material can be used on both the front and back sides, which is advantageous in practice. The tarpaulin sheet according to the present invention has excellent advantages as described above, and can be applied to sports clothing, raincoats, tent fabrics, etc., making it an extremely useful tarpaulin sheet.

[Brief explanation of the drawing]

FIG. 1 is a schematic explanatory diagram showing the structure of a waterproof sheet according to the present invention. 10... Waterproof sheet, 11... First membrane-like material, 1
2... Second membrane-like substance, 13, 14... Micropore, 15...
...an intermediate hygroscopic layer comprising a hygroscopic substrate.

Claims (1)

[Claims for Utility Model Registration] (1) Two membrane-like materials made of a high-molecular polymer material and having numerous micropores that allow water vapor particles to pass through but not raindrops, and the two membranes. What is claimed is: 1. A waterproof sheet, characterized in that it is formed by integrating an intermediate hygroscopic layer including a hygroscopic base material disposed between a hygroscopic material and a hygroscopic material. (2) The waterproof sheet according to claim 1, wherein the average diameter of the pores of each of the two membrane-like materials is approximately equal.