High-pressure fluid protection sheet

Abstract

To provide a protection sheet which is suitable for work with a high-pressure jet water flow, can also protect against a low-pressure water flow, and can also withstand for a case in which a high-pressure fluid is continuously injected in a manner concentrated on a single point.SOLUTION: A protection sheet 1 includes: a first layer 10 provided on a front surface; a second layer 20 provided on a rear surface of the first layer; and a third layer 30 provided on a rear surface of the second layer. The first layer 10 and the third layer 30 are sheets formed of a para-aramid fiber nonwoven fabric impregnated with NBR. In the second layer 20, a holding section 23 in which liquid is held by a nonwoven fabric 21 and a fluid holding member 22 is formed. The first layer 10 of the protection sheet 1 ensures waterproofness. Even if the first layer 10 is cracked by a high-pressure jet water flow W, water entered into the second layer 20 is held in the holding section 23 by the nonwoven fabric 21 and the fluid holding member 22, which exerts a shock-absorbing effect on water which is going to enter further.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present invention relates to a protective sheet capable of protecting a worker from high-pressure fluids such as high-pressure jet water. [Background technology]

[0002] Conventionally, processing, cleaning, and other work have been performed using high-pressure fluids such as high-pressure jet water streams sprayed from a nozzle, and various protective clothing for protecting workers have been proposed. For example, Patent Document 1 discloses a multi-layer structure for blocking high-pressure water sprayed from a nozzle, which includes a double-knit impact absorbing layer made of ultra-high molecular weight polyethylene fibers that absorbs the impact of the high-pressure water by stretching the fibers, a fabric breakage prevention layer that prevents the fibers of the impact absorbing layer from breaking, and a waterproof layer that prevents the high-pressure water that has passed between the fibers of these two layers from penetrating into the interior. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 6244352 Summary of the Invention [Problem to be solved by the invention]

[0004] The multilayer structure described in Patent Document 1 comprises a knitted impact absorbing layer that absorbs the impact of high-pressure water by stretching its fibers, a woven breakage prevention layer that prevents the impact absorbing layer from breaking, and a waterproof layer that prevents the high-pressure water that has passed through these two layers from leaking toward the body.

[0005] In the multilayer structure of Patent Document 1, the impact of the high-pressure water is absorbed by the impact absorbing layer by causing the impact area to concave and the fibers to stretch, the breakage prevention layer prevents the impact absorbing layer from stretching too much and breaking, and the waterproof layer prevents water from entering the body.

[0006] However, this configuration has the disadvantage that the shock absorbing layer and the breakage prevention layer absorb water and become heavy even when low-pressure water, such as water rebounding from an object to be processed or cleaned, is applied during work using high-pressure water. Also, since the shock absorbing layer and the breakage prevention layer are both made of materials that allow water to pass through, if high-pressure fluid is sprayed continuously at one point, the burden on the waterproof layer becomes large and the high-pressure water may break the waterproof layer.

[0007] The present invention aims to provide a protective sheet suitable for work using high-pressure fluids such as high-pressure jet water streams, which is waterproof even against low-pressure water streams and can withstand continuous sprays of high-pressure fluid concentrated at one point. [Means for solving the problem]

[0008] In order to achieve the above-mentioned object, the present invention provides a protective sheet for protecting a protected object from a high-pressure fluid, comprising at least a first layer provided on a surface and made of a waterproof material, a second layer provided on the back surface of the first layer, and a third layer provided on the back surface of the second layer, wherein the first layer is made of a woven or nonwoven fabric made from super fiber and impregnated with a rubber-based material, the second layer is formed from a hydrophilic material, and the third layer is formed from a waterproof material.

[0009] According to the protective sheet of the present invention, the first layer is made of a woven or nonwoven fabric made of superfiber impregnated with a rubber-based material, and is made of a waterproof material, so that it can be waterproofed even against low-pressure water flows. In addition, since the first layer is made of superfiber and a rubber-based material, it is flexible and has good workability when used in protective clothing, etc. In addition, even if high-pressure fluid is continuously sprayed at one point and some of the fluid passes through by causing cracks in the first layer, the second layer is made of a hydrophilic material, so the liquid (water) is retained in the second layer.

[0010] The liquid held in this second layer acts as a buffer for the high-pressure fluid seeping in through cracks in the first layer, mitigating the impact of the fluid reaching the third layer. This makes the protective sheet of the present invention waterproof even against low-pressure water flows, and it can withstand even continuous sprays of high-pressure fluid concentrated at one point.

[0011] In the protective sheet of the present invention, the second layer may include a fluid retaining member that contacts the first layer and the third layer to form a retaining compartment. A retaining compartment is a compartment that is capable of retaining a fluid and inhibiting leakage of the fluid into other compartments. With this configuration, even if a crack occurs in the first layer and part of the high-pressure fluid penetrates, the liquid can be retained in the second layer, thereby ensuring the buffering effect of the second layer.

[0012] In this configuration, the second layer may be formed of a nonwoven fabric, and the fluid holding member may be formed of a water-absorbent resin member held by the nonwoven fabric. By configuring the fluid holding member in this way, the fluid holding member can hold the liquid in the second layer. Even if high-pressure fluid is concentrated and continuously sprayed at a location where the fluid holding member is located, a buffering effect can be generated by the liquid held by the water-absorbent resin member.

[0013] Furthermore, this configuration allows the second layer of nonwoven fabric and the fluid retention member to be integrally formed, facilitating production when the protective sheet of the present invention is used in protective clothing, etc. Here, being held by the nonwoven fabric refers to fixing the water-absorbent resin member to the nonwoven fabric by means of applying a gelled water-absorbent resin member to the nonwoven fabric and drying it, or by heating a powdered water-absorbent resin member to adhere to the nonwoven fabric.

[0014] In the protective sheet of the present invention, the super fiber may be any one of para-aramid fiber, meta-aramid fiber, ultra-high molecular weight polyethylene fiber, polyarylate fiber, and polyparaphenylene benzobisoxazole fiber. The above-mentioned multiple super fibers have different properties and prices, and can be appropriately selected depending on the properties and price of products such as protective clothing and protective gloves formed using the protective sheet of the present invention. These super fibers may also be used in combination.

[0015] In the protective sheet of the present invention, the first layer may be formed by impregnating the superfiber with acrylonitrile butadiene rubber as the rubber-based material and subjecting it to a heat and pressure treatment. According to the inventors of the present application, a protective sheet with high protective performance was obtained by using this combination of materials. Effect of the Invention

[0016] According to the present invention, it is possible to obtain a protective sheet suitable for work using high-pressure fluids such as high-pressure jet water streams, which is waterproof even against low-pressure water streams, and can withstand continuous sprays of high-pressure fluid concentrated at one point. [Brief description of the drawings]

[0017] [Figure 1] 1A and 1B are explanatory views showing a protective sheet of the present invention, in which (A) is an explanatory view showing a cut surface of the protective sheet, and (B) is a cross-sectional view taken along line BB in (A). [Diagram 2] FIG. 2 is an explanatory diagram showing protective clothing using the protective sheet of the present embodiment. [Diagram 3] 5 is an explanatory diagram showing the effect of the protective sheet of the present embodiment against a high-pressure jet water stream. FIG. [Figure 4] 1 is a graph showing the penetration time of a high-pressure water jet for each test piece. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0018] Next, a protective sheet 1 as an example of an embodiment of the present invention will be described with reference to Figures 1 to 4. The protective sheet 1 of this embodiment is a sheet that protects a protected body such as a human body from a high-pressure jet water stream W (high-pressure fluid) sprayed from a nozzle N, and as shown in Figure 1, is composed of a first layer 10 provided on the front surface, a second layer 20 provided on the back surface of the first layer 10, and a third layer 30 provided on the back surface of the second layer 20. In this embodiment, a fluid retaining member 22 that contacts the first layer 10 and the third layer 30 to form a retaining section 23 is provided in a part of the second layer 20.

[0019] The first layer 10 is a sheet formed by impregnating a nonwoven fabric made from para-aramid fiber, a type of super fiber, with acrylonitrile butadiene rubber (hereinafter referred to as "NBR") and carrying out a heating and pressurizing process called hot pressing. Specifically, the nonwoven fabric made from para-aramid fiber was impregnated with NBR by a hand lay-up method, dried, heated to 100°C or higher in a press, and pressed at 15 MPa or higher for 30 minutes to several hours. Since the nonwoven fabric in the first layer 10 is impregnated with NBR, it is a waterproof sheet made of a waterproof material that does not allow water to pass through.

[0020] As the para-aramid fiber, Kevlar (registered trademark), a product of DuPont, can be used. Alternatively, as the super fiber, Izanas (registered trademark), an ultra-high molecular weight polyethylene fiber manufactured by Toyobo Co., Ltd., can be used. As the super fiber, other known materials such as meta-aramid fiber, polyarylate fiber, polyparaphenylene benzobisoxazole fiber, or polyacrylonitrile carbon fiber can be appropriately used.

[0021] In this embodiment, NBR is used as the rubber material. Among rubber materials, NBR is excellent in flexibility and abrasion resistance, and is also a material with high pressure resistance. Other examples of rubber materials that can be used include isoprene rubber (IR), butadiene rubber (BR), styrene butadiene rubber (SBR), urethane resin, thermoplastic elastomer, and flexible thermosetting polyurethane elastomer.

[0022] The second layer 20 is made of a nonwoven fabric and has hydrophilic properties. As shown in Fig. 1(B), the second layer 20 has a synthetic resin nonwoven fabric 21 holding a fluid holding member 22, which is a hydrophilic water-absorbent resin member, in a lattice pattern. The fluid holding member 22 is in contact with the back surface of the first layer 10 and the front surface of the third layer 30, and a holding section 23 is formed in the portion surrounded by the fluid holding member 22.

[0023] As the nonwoven fabric 21, any commonly used material can be used. For example, spunbond nonwoven fabric, spunlace nonwoven fabric, or needle punch nonwoven fabric can be used. Materials that can be used include polypropylene, polyester, nylon, and the like. In addition to the nonwoven fabric 21, materials such as woven fabric and urethane foam can be used in the second layer 20 as long as they are hydrophilic.

[0024] A known polymer water-absorbing material is used as the fluid holding member 22. As the polymer water-absorbing material, an absorbent resin (polymer water-absorbing material) such as SAP (Super Absorbent Polymer) can be used. SAP is a hydrophilic polymer with a cross-linked structure that absorbs and holds water. In addition to this, known water-retaining materials such as polyacrylamide, carboxymethyl cellulose, or polyvinyl alcohol may also be used as the fluid holding member 22.

[0025] Since the second retention layer 20 has the above-mentioned configuration, a sheet of nonwoven fabric 21 with the fluid retention members 22 held in a lattice pattern can be prepared in advance, and then cut and used according to the application of the protective suit 2, other gloves, etc. Therefore, it can be handled in the same way as normal fabric materials, making production easy.

[0026] In this embodiment, the third layer 30 uses a waterproof sheet similar to that of the first layer 10. The third layer 30 only needs to have waterproof properties that prevent water from entering when water penetrates the second layer 20, but the protective performance can be further improved by using a sheet using super fiber.

[0027] The protective sheet 1 of this embodiment can be used, for example, in protective clothing 2 shown in FIG. 2. The protective clothing 2 is formed into the shape of the protective clothing 2 by appropriately cutting and sewing the protective sheet 1. This protective clothing 2 is formed so as to cover the torso, arms, and neck of the wearer. The fluid retaining member 22 may be retained in the sewn parts. In addition, the protective sheet 1 of this embodiment can be used for protective gear such as helmets, gloves, slacks, boots, and aprons. The protective sheet 1 of this embodiment is flexible, and therefore has good workability when used for the protective clothing 2, gloves, slacks, and the like.

[0028] Because the protective sheet 1 of this embodiment has the above-mentioned configuration, even if a high-pressure jet water stream W is sprayed from a nozzle N onto the protective sheet 1, as shown in Figure 3(A), it is protected by the first layer 10. The first layer 10 is made by impregnating a nonwoven fabric of para-aramid fiber, which is a super fiber, with NBR, and is water-resistant and abrasion-resistant, so that it can provide protection against continuous spraying of the high-pressure jet water stream W for a relatively long period of time.

[0029] If the high-pressure jet water stream W is sprayed continuously for a long period of time, as shown in Fig. 3(B), a crack may appear in part of the first layer 10, allowing the water stream to reach the second layer 20. Even in such a case, the water that has penetrated into the second layer 20 is retained by the nonwoven fabric 21, which acts as a buffer against the water that attempts to penetrate further.

[0030] Water impregnated in nonwoven fabric 21 moves downward due to gravity, but since second layer 20 has retention compartment 23 formed by fluid retention member 22, when the water moves downward inside nonwoven fabric 21, it is retained by fluid retention member 22. As a result, in retention compartment 23 of second layer 20 into which water has penetrated, water is retained in nonwoven fabric 21, and the buffering effect of water attempting to further infiltrate is maintained.

[0031] In this embodiment, SAP is used as the fluid retention member 22. This SAP is a material used in disposable diapers and the like, and becomes gel-like when it absorbs water, so that it can prevent water from leaking out from the retention compartment 23. Therefore, even if a crack occurs in the first layer 10, water is retained only in the retention compartment 23 where the crack occurs, and water does not leak into other retention compartments 23. This minimizes an increase in the weight of the protective clothing 2 caused by water entering through a crack in the first layer 10.

[0032] Figure 4 is a graph showing the results of spraying a high-pressure water jet W at a pressure of 3 MPa from a distance of 200 mm against a test piece and measuring the time until the test piece penetrates. The vertical axis of the graph shows the cumulative probability (%), and the horizontal axis shows the time (seconds).

[0033] The graph plots the penetration time results for five types of test pieces, and from the left, ○: sheet containing only NBR, △: sheet containing only super fiber (para-aramid fiber) nonwoven fabric, □: sheet in which super fiber (para-aramid fiber) nonwoven fabric has been impregnated with NBR and hot pressed, ●: protective sheet of this embodiment without fluid retaining member 22, ▲: protective sheet 1 of this embodiment which is provided with fluid retaining member 22.

[0034] 4, the sheet made only of NBR (◯) was penetrated in 10 seconds or less under this test environment, and the sheet made only of superfiber nonwoven fabric (△) had an average penetration time of about 6 seconds. Even the sheet made of superfiber nonwoven fabric (□), which corresponds to the first layer 10 of this embodiment and is impregnated with NBR, had an average penetration time of about 10 seconds.

[0035] In contrast, the protective sheet of this embodiment that does not have the fluid retaining member 22 (●) had an average penetration time of approximately 20 minutes, a significant increase in the penetration time. Furthermore, the protective sheet 1 of this embodiment (▲) had an average penetration time of over 30 minutes, indicating that the retention of water in the retention compartment 23 by the fluid retaining member 22 contributes to preventing penetration.

[0036] In the above embodiment, the first layer 10 uses a nonwoven fabric made of superfiber, but the present invention is not limited to this and a woven fabric made of superfiber may be used. In this case, the woven fabric may be a plain weave, twill weave, satin weave, or other woven fabric.

[0037] In the above embodiment, the second layer 20 is formed by holding the fluid holding members 22 in a lattice pattern on the nonwoven fabric 21, but other configurations may be adopted as long as the second layer 20 is capable of holding water. For example, the nonwoven fabric 21 may be impregnated with a synthetic resin having waterproofness and flexibility, or a double-sided adhesive tape may be arranged in a lattice pattern, with the nonwoven fabric 21 arranged inside a rectangle (not shown). In this case, by using a porous body for the double-sided adhesive tape, the double-sided adhesive tape can hold water, further improving the penetration resistance.

[0038] In the above embodiment, the third layer 30 uses a waterproof sheet similar to that of the first layer 10, but the third layer 30 is not limited to this, and any sheet having waterproof properties may be used. For example, a nonwoven fabric made of normal fibers other than superfibers may be impregnated with NBR or the like, or a flexible synthetic resin sheet may be used. A breathable waterproof fabric may also be used.

[0039] In addition, in the above embodiment, the protective sheet 1 has a three-layer structure consisting of the first layer 10 to the third layer 30, but this is not limited to this, and a cloth lining, a cushioning cloth, or a cold-weather cloth may be further layered on the back surface of the third layer 30. [Explanation of symbols]

[0040] 1...Protective sheet 2…Protective clothing 10…1st layer 20…Second layer 21...Nonwoven fabric 22...Fluid retaining member 23…Holding section 30…Third layer

Claims

1. A protective sheet that protects a protected object from a high-pressure fluid, The waterproofing sheet includes at least a first layer provided on a surface thereof and made of a waterproof material, a second layer provided on a back surface of the first layer, and a third layer provided on a back surface of the second layer; The first layer is made by impregnating a woven or nonwoven fabric made of super fiber with a rubber-based material, the second layer is formed of a hydrophilic material, A protective sheet, wherein the third layer is made of a waterproof material.

2. 2. The protective sheet according to claim 1, A protective sheet, wherein the second layer includes a fluid retaining member that contacts the first layer and the third layer to form a retaining compartment.

3. The protective sheet according to claim 2, A protective sheet, wherein the second layer is formed of a nonwoven fabric, and the fluid holding member is formed of a water-absorbent resin member held by the nonwoven fabric.

4. 2. The protective sheet according to claim 1, The super fiber is a protective sheet made of any one of para-aramid fiber, meta-aramid fiber, ultra-high molecular weight polyethylene fiber, polyarylate fiber, and polyparaphenylene benzobisoxazole fiber.

5. 2. The protective sheet according to claim 1, The first layer is a protective sheet characterized in that it is formed by impregnating the super fiber with acrylonitrile butadiene rubber as the rubber-based material and subjecting it to a heating and pressurizing treatment.

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