Oil leak detection material

Abstract

To provide a leakage oil detection material capable of detecting leakage oil with high sensitivity, quickly, in a short time, and surely even in a wet state without the risk of mistaking it for leakage oil even if it gets wet with water such as rainwater.SOLUTION: The oil leakage detection material includes a colored layer (16) having oil absorbency, a white layer (14) provided in contact with an upper surface of the colored layer (16), the white layer (14) containing white powder and having oil absorbency, a protective layer (12) provided to cover an upper surface of the white layer (14), the protective layer (12) being made of a transparent hydrophobic resin, and an oil absorbing layer (18) provided on a lower surface side of the colored layer (16), the oil absorbing layer (18) having oil absorbency and oil retainability and water repellency. A through-hole reaching the oil absorbing layer 18 from the outside is formed between the adjacent laminated pieces 17 and the leaked oil is absorbed by the oil absorbing layer 18 to permeate the colored layer 16 and the white layer 14 and the white layer 14 becomes a transparent state or a translucent state and the hue of the colored layer 16 can be visually observed through the protective layer 12.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to an oil leak detector that can reliably detect oil leaks and temporarily retain leaked oil. [Background technology]

[0002] To detect oil leaks from welds in tanks and containers storing oil, or from oil pipe joints, etc., during regular inspections, when the tank or container is empty and no oil is flowing through the oil pipes, nitrogen gas is sealed into the empty tank, container, or oil pipes to a specified pressure, and the rate of pressure drop of the nitrogen gas is observed to check for leaks. However, while oil leaks from tanks and containers storing oil or oil pipes through which oil is flowing must be detected visually, small oil leaks may not be detected visually. Furthermore, if leaking oil drips onto the ground, it can cause soil contamination.

[0003] As a detection material capable of detecting oil leaks from tanks or containers in which oil is stored or oil pipes through which oil flows, Patent Document 1 below proposes an oil leak detection material having a colored layer made of a synthetic resin having water permeability and oil retention properties to absorb and retain oil, formed of a nonwoven fabric having a thickness of 200 μm or more, the nonwoven fabric being colored, and a white layer having a thickness of at least 150 μm laminated to one side of the colored layer, which is opaque when wet with water and becomes transparent when wet with oil, and in which white powder with a refractive index of 1.5 to 1.6 is dispersed in a transparent resin so that the hue of the colored layer can be seen through. This oil leak detector can detect oil leaks from tanks and containers in which oil is stored, and from oil pipes through which oil flows.

[0004] However, when this oil leak detection material gets wet with water such as rainwater, the white layer becomes slightly transparent, which may lead to the risk of it being mistaken for an oil leak. It was also found that if the white layer of a water-soaked oil leak detection material does not dry sufficiently, the leaked oil does not penetrate the white layer sufficiently, resulting in insufficient transparency of the white layer and making it impossible to reliably detect oil leaks. Furthermore, since the refractive index of the white powder in the white layer is 1.5 to 1.6, it was also found that the white layer does not become sufficiently transparent when using silicone oil with a refractive index of 1.4, making it difficult to detect silicone oil leaks.

[0005] The applicant has already filed a patent application in Patent Document 2 for an oil leak detection device comprising: a colored layer colored in a predetermined color and having oil-absorbing properties; an oil-absorbing white layer provided in contact with at least a portion of the upper surface of the colored layer, the white layer having white particles or white powder contained in or attached to a transparent resin layer; a protective layer made of a transparent hydrophobic resin provided so as to cover the upper surface of the white layer; and an oil-absorbing layer provided on the lower surface of the colored layer, the oil-absorbing and oil-retaining properties being formed from a material having water-repellency or having been treated with a water-repellent coating; the colored layer and the white layer are sandwiched between the protective layer and the oil-absorbing layer so as to prevent water from penetrating into the colored layer and the white layer; when leaked oil or leaked oil and water come into contact with at least a portion of the surface of the oil-absorbing layer, only the leaked oil is absorbed by the oil-absorbing layer and penetrates into the colored layer and the white layer, the white layer becomes transparent or translucent, and the hue of the colored layer can be seen with the naked eye through the protective layer. This invention makes it easy to detect oil leaks even with silicone oil, which has a refractive index of 1.4. However, this invention detects oil leaks by absorbing oil only from the exposed side of the oil-absorbing layer, and it has been desired to further improve the sensitivity and speed of oil leak detection. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Patent No. 6609085 [Patent Document 2] Patent application 2023-140007 Summary of the Invention [Problem to be solved by the invention]

[0007] To provide an oil leak detection material which, even when wet with water such as rainwater, is not likely to be mistaken for an oil leak, can detect oil leaks with high sensitivity, quickly, in a short time and reliably even when wet, and can detect oil leaks even from oils such as silicone oils with a refractive index of less than 1.5. [Means for solving the problem]

[0008] The oil leak detection material made to achieve the above object comprises a colored layer colored in a predetermined color and having oil-absorbing properties, a white layer having oil-absorbing properties and being laminated in contact with at least a part of the upper surface of the colored layer and having white particles or white powder contained in or attached to a transparent resin layer, a protective layer made of a transparent hydrophobic resin and being provided so as to cover the upper surface of the white layer, and an oil-absorbing layer provided on the lower surface side of the colored layer, having oil-absorbing and oil-retaining properties, and being formed of a material having water-repellency or having been subjected to a water-repellent treatment, and a plurality of laminated pieces of the colored layer and the white layer are arranged side by side, and the oil leak detection material has a plurality of laminated pieces of the colored layer and the white layer, and between the adjacent laminated pieces, there is a gap between the outside world and the white layer. The oil-absorbing layer has through-holes extending from the oil-absorbing layer to the protective layer, and the colored layer and the white layer are sandwiched between the protective layer and the oil-absorbing layer to prevent water penetration into the colored layer and the white layer. The difference in refractive index between the oil to be detected for oil leakage, which has a refractive index of 1.40 to 1.55, and the white particles or white powder is 0.1 or less. When leaked oil or leaked oil and water come into contact with at least a portion of the oil-absorbing layer, only the leaked oil is absorbed by the oil-absorbing layer and penetrates the colored layer and the white layer, causing the white layer to become transparent or translucent, allowing the color of the colored layer to be visually observed through the protective layer. The through-holes increase the exposed area of ​​the oil-absorbing layer, facilitating oil absorption and enabling reliable oil leakage detection with high sensitivity and speed in a short period of time. The through-holes facilitate oil absorption and enable reliable detection, and when leaked oil comes into contact with water, they absorb the leaked oil into the oil-absorbing layer while allowing water such as rainwater to be discharged, contributing to preventing stagnation. Furthermore, since the difference in refractive index between the white particles or white powder and the leaked oil to be detected is 0.1 or less, when the leaked oil to be detected penetrates the white layer, the white layer becomes sufficiently transparent, allowing the hue of the colored layer to be reliably observed visually, which is preferable.

[0009] This oil leak detection material is preferably formed such that the through holes penetrate the oil leak detection material together with the oil absorption layer between adjacent laminated pieces, thereby bringing at least a portion of the oil absorption layer into direct contact with the leaked oil or the leaked oil and water, which, combined with the fact that a portion of the peripheral surface of the oil absorption layer is formed on an exposed surface so as to come into direct contact with the leaked oil or the leaked oil and water, allows for more rapid and reliable detection of oil leaks.

[0010] This oil leak detection material is even more preferable when the oil absorption layer has one or more transmission holes facing the laminated piece, as the transmission holes, combined with the through holes, can detect oil leaks more quickly and reliably.

[0011] In this oil leakage detection material, one or more through holes may be formed between adjacent laminated pieces.

[0012] This oil leakage detection material is even more preferable when the through-holes have a hole shape selected from the group consisting of circular, elliptical, rectangular, and rectangular with rounded corners, as this makes it easier for leaked oil to penetrate the through-holes and soak into the oil absorption layer, allowing for faster and more reliable detection of oil leakage.

[0013] This oil leakage detection material is preferable because the oil absorbing layer is made of hydrophobic synthetic resin fibers and is a fabric that exhibits water repellency, thereby improving oil retention.

[0014] In this oil leak detection material, the oil absorption layer and the colored layer are bonded together via an oil-philic first hydrophobic adhesive layer, and the colored layer and the white layer are sandwiched between the protective layer and the first hydrophobic adhesive layer, thereby ensuring a tight bond between the oil absorption layer and the colored layer.

[0015] This oil leak detection material is preferable because the protective layer and the white layer are bonded together via a transparent second hydrophobic adhesive layer, and the white layer and the colored layer are sandwiched between the second hydrophobic adhesive layer and the oil absorbing layer, so that the side surfaces of the white layer and the colored layer and the top surface of the white layer can be reliably covered by the second hydrophobic adhesive layer.

[0016] This oil leak detection material has a transparent second hydrophobic adhesive layer arranged around the white layer and the colored layer with a gap between them, and the protective layer and the oil absorption layer are joined together via the second hydrophobic adhesive layer while sandwiching the white layer and the colored layer, thereby preventing the second hydrophobic adhesive layer from unexpectedly discoloring or losing its water resistance due to deterioration caused by ultraviolet rays, etc.

[0017] In this oil leakage detection material, it is preferable that the colored layer is any color selected from black, navy blue, red, orange, blue, green, brown, and purple, since this makes it clearly different from the white color of the white layer.

[0018] This oil leak detection material is preferable if the colored layer and / or the white layer are shaped in the shape of letters, symbols, and / or figures, or if the colored layer is printed in the shape of letters, symbols, and / or figures, because these shapes can be made to appear or disappear in the event of an oil leak.

[0019] This oil leak detection material is preferable because the particle size of the white particles or white powder is 20 μm or less, so that discoloration of the oil leak detection material due to oil leakage becomes clear.

[0020] This oil leak detection material is even more preferable if the white particles or white powder are selected from organic compounds, plastic powders, metal salts, glass beads and glass fillers, as this makes discoloration of the oil leak detection material due to oil leakage clearer and more noticeable. [Effects of the Invention]

[0021] According to the present invention, the oil leak detection material has through-holes, which allow leaked oil to quickly reach the oil-absorbing layer through the through-holes, accelerating the coloring of the coloring agent and enabling reliable oil leak detection with high sensitivity and speed in a short period of time. Furthermore, when the target leak oil penetrates the white layer, even if the difference in refractive index between the white particles or white powder and the target leak oil is 0.1 or less, the white layer becomes sufficiently transparent, allowing the hue of the colored layer to be reliably observed. The white and colored layers of the oil leak detection material are waterproofed by being covered with a protective layer made of a transparent hydrophobic resin and an oil-absorbing and oil-retaining material with water-repellent properties or treated with a water-repellent coating. Even if the oil leak detection material becomes wet with water such as rainwater, water does not penetrate the oil-absorbing layer, white layer, or colored layer, preventing misidentification due to the white layer becoming transparent upon wetting. Furthermore, because the oil-absorbing layer is also water-repellent, it does not absorb water such as rainwater, allowing oil leaks to be detected even when the oil leak detection material is wet. This oil-absorbing layer has oil-retaining properties and can retain leaked oil that penetrates into the colored layer and the white layer, allowing for reliable detection of leaked oil. Furthermore, the white particles or white powder of the white layer can be selected to be optimal in relation to the refractive index of the oil that is the object of oil leakage detection. [Brief explanation of the drawings]

[0022] [Figure 1] 1A and 1B are a partially cutaway plan view and a schematic cross-sectional view of an oil leakage detection material to which the present invention is applied. [Figure 2] 2 is a partially cutaway plan view of the oil leakage detection material of FIG. 1 when leaked oil is absorbed by the oil absorption layer of the oil leakage detection material. FIG. [Figure 3] FIG. 10 is a schematic cross-sectional view of another example of an oil leakage detection material to which the present invention is applied. [Figure 4] FIG. 10 is a schematic cross-sectional view of another example of an oil leakage detection material to which the present invention is applied. [Figure 5] FIG. 10 is a schematic cross-sectional view of another example of an oil leakage detection material to which the present invention is applied. [Figure 6] 10 is a partially cutaway plan view of another example of an oil leakage detection material to which the present invention is applied. FIG. [Figure 7] FIG. 10 is a plan view of another example of an oil leakage detection material to which the present invention is applied. [Figure 8] 1 is a perspective view showing an example of a state in which an oil leakage detection material to which the present invention is applied is used. DETAILED DESCRIPTION OF THE INVENTION

[0023] FIG. 1(a) shows a front view of an example of an oil leakage detection material to which the present invention is applied, and FIG. 1(b-1) shows a cross-sectional view thereof taken along line XX. The oil leak detection material 10 shown in FIG. 1(a) is rectangular, as shown in FIG. 1(a), and includes a rectangular colored layer 16 colored in a predetermined color, and a white layer 14 that is rectangular and approximately the same size as the colored layer 16 and is laminated in close contact with and on the upper surface of the colored layer 16. The material includes a plurality of rectangular laminated pieces 17 arranged in series, each having a size of 1 to 150 mm square or a short side of 1 to 149 mm and a long side of 2 to 150 mm. The laminated pieces 17 are larger than the colored layer 16 and the white layer 14 and are rectangular or tape-shaped, having a short side of 3 to 200 mm and a long side of 5 mm to several meters. The protective layer 12 is provided so as to cover the upper surface of the white layer 14, and is larger than the colored layer 16 and the white layer 14 and has a short side of 3 to 200 mm and a long side of 5 mm to several meters. The protective layer 12 is provided so as to cover the upper surface of the white layer 14, and is an oil-absorbing layer 18 bonded to the lower surface of the colored layer 16 via a first hydrophobic adhesive layer 20. The release paper 24 is bonded to the lower surface of the oil-absorbing layer 18 via a release paper adhesive layer 22. The white layer 14 and the colored layer 16 are sandwiched between the protective layer 12 and the first hydrophobic adhesive layer 20. The oil leak detection material 10 has through holes 11 formed between adjacent laminated pieces 17 with a gap 27 of 1 to 150 mm therebetween, the through holes 11 being smaller than the gap 27 and extending from the outside to the oil absorbing layer 18. This allows leaked oil to permeate only the outer periphery of the oil absorbing layer 18 of the oil leak detection material 10, and further into the oil absorbing layer 18 where it has permeated and migrated through the adhesive layers 20 and 22, causing the oil leak detection material to discolor.

[0024] As shown in Figure (b-1), the through holes 11 between adjacent laminate pieces 17 penetrate the protective layer 12, first hydrophobic adhesive layer 20, oil-absorbing layer 18, release paper adhesive layer 22, and release paper 24 between adjacent laminate pieces 17. This allows at least a portion of the oil-absorbing layer 18 to come into direct contact with leaked oil or leaked oil and water.

[0025] Furthermore, as shown in Figure (b-2), the oil absorbing layer 18 may have one or more through holes 19 facing the laminated piece 17. This increases the number of areas where at least a portion of the oil absorbing layer 18 comes into direct contact with the leaked oil or the leaked oil and water.

[0026] The through hole 11 between adjacent laminated pieces 17 is singular and has a rectangular hole shape with rounded corners and short sides of 0.1 to 140 mm and long sides of 0.1 to 140 mm, but there may be multiple through holes and they may have a circular or elliptical shape with a diameter of 0.1 to 140 mm, or a square shape of 0.1 to 140 mm square or a rectangular hole shape with short sides of 0.1 to 140 mm and long sides of 0.1 to 140 mm.

[0027] The colored layer 16 can be made of oil-absorbent materials, such as paper, nonwoven fabric, woven fabric, porous inorganic materials such as porous cement, porous ceramics, and porous metal, foamed plastics, or ink coatings. These materials are colored a predetermined color. The coloring is preferably achieved with a colorant, such as a pigment, dye, or a mixture thereof, that is resistant to fading in sunlight and has excellent lightfastness. A hue that contrasts clearly with white and is easily recognizable by the naked eye or an image sensor is preferred, particularly a chromatic color such as black, navy blue, red, orange, blue, green, brown, or purple. Because black and navy blue tend to change in brightness and may be mistaken for shadows, red, which changes in saturation and is a dangerous color, is practical and even more preferred. The colorant is preferably water- and oil-resistant. The coloring may be applied to the material that constitutes the oil-absorbent material, or to a material that has been molded into a predetermined shape. The colored layer 16 preferably has a thickness of 1 to 150 μm.

[0028] A rectangular white layer 14 of approximately the same size as the colored layer 16 is provided on the upper surface of the colored layer 16 in close contact with the upper surface of the colored layer 16. The white layer 14 contains white particles or white powder in an oil-absorbing transparent resin layer. When leaked oil penetrates the white layer 14, it becomes transparent or translucent. This phenomenon occurs because light that has passed through the leaked oil can pass through the white layer 14 without being significantly bent at the boundary with the white powder or white particles.

[0029] Examples of such white powders or particles include organic compound powders or particles such as fatty acid derivatives, alcohol derivatives, ether derivatives, aldehyde derivatives, ketone derivatives, amine derivatives, amide derivatives, nitrile derivatives, hydrocarbon derivatives, thiol derivatives, and sulfide derivatives; polyvinyl chloride, polyethylene, polypropylene, polystyrene, acrylonitrile-butadiene-styrene, acrylonitrile-styrene, polymethyl methacrylic, polyvinyl alcohol, polyvinylidene chloride, polyethylene terephthalate, polyamide, polyacetal, polycarbonate, polyphenylene ether, poly Examples of the resin include plastic powders or particles such as butylene terephthalate, polyvinylidene fluoride, polysulfone, polyethersulfone, polyphenylene sulfide, polyarylate, polyamideimide, polyetherimide, polyetheretherketone, polyimide, liquid crystal polymer, polytetrafluoroethylene, phenolic resin, urea resin, melamine resin, unsaturated polyester, epoxy resin, silicone resin, and polyurethane; alkaline earth metal salts such as magnesium carbonate and calcium carbonate; metal salt powders or particles such as aluminum hydroxide and talc; glass beads; and glass fillers.

[0030] The white powder or white particles are preferably selected so that the difference in refractive index between them and the target oil is 0.1 or less. The target oils for oil leak detection are hydrophobic oils derived from minerals, animals, or plants, such as petroleum, that float on water, and that are liquid at room temperature, and have a refractive index of 1.40 to 1.55, such as insulating oil, kerosene, light oil, heavy oil, linseed oil, paraffin oil, silicone oil, and hydraulic oil. When such oils are the target for oil leak detection, the white powder or white particles are preferably stearic acid (refractive index 1.43), talc (refractive index 1.54), urea resin powder (refractive index 1.57), calcium carbonate (refractive index 1.50 to 1.64), aluminum hydroxide (refractive index 1.57), magnesium carbonate (refractive index 1.52 to 1.53), glass beads (refractive index 1.52 to 1.57), or glass filler (refractive index 1.50 to 1.58). The white powder or white particles may be an organic compound, for example, a fatty acid or a salt thereof, specifically calcium stearate (refractive index 1.46), a fatty acid amide, a metal soap, or paraffin. These white powders or white particles may be used alone or in combination of two or three types. The particle size of the white powder or white particles is preferably 20 μm or less, and particularly preferably 10 μm or less, since this enhances the light scattering effect and increases the whiteness of the white layer 14. The particle size of the white powder or white particles was measured with a grind meter.

[0031] The white layer 14 shown in FIGS. 1(a) and (b-1) to (b-2) is formed by dispersing white powder or white particles in an oil-absorbing transparent resin layer. The transparent resin is an oil-philic transparent resin, such as a cellulose-based resin, a polyester-based resin, an acrylic-based resin, a urethane-based resin, or a synthetic rubber-based resin. Cellulose-based resins (e.g., ethyl cellulose) and polyester-based resins are particularly preferred. The amount of white powder or white particles mixed with the transparent resin is preferably 0.5 to 15 times the mass of the transparent resin.

[0032] The thickness of the white layer 14 is preferably 1 μm or more, which makes the white layer 14 sufficiently opaque. The upper limit of the thickness of the white layer 14 is preferably 260 μm or less in relation to the flexibility of the oil leak detection material 10. The white layer 14 may be formed by applying white powder or white particles directly or via an adhesive layer to one or both sides of a lipophilic transparent resin layer of a predetermined thickness.

[0033] The protective layer 12 is larger than the colored layer 16 and the white layer 14, and covers the top surface of the white layer 14 and the side surfaces of the colored layer 16 and the white layer 14. The protective layer 12 is formed of a transparent hydrophobic resin. Examples of transparent hydrophobic resins include cellulose, cellulose derivatives, polyolefin, polyvinyl chloride, polyvinylidene chloride, polyvinyl alcohol, polyester, polystyrene, rubber hydrochloride, polyamide, fluororesin, polybutene, polyvinyl butyral, polyethylene oxide, polyurethane, cellulose acetate butyrate, hydroxyethyl cellulose, and polyimide.

[0034] The colored layer 16 has an oil-absorbing layer 18 bonded to its underside via a first hydrophobic adhesive layer 20. The oil-absorbing layer 18 is larger than the colored layer 16 and the white layer 14, and has oil-absorbing and oil-retaining properties, and is formed from a water-repellent material or has been treated to be water-repellent. As the oil-absorbing layer 18, fabrics such as nonwoven fabrics and woven fabrics made of hydrophobic synthetic resin fibers and exhibiting water-repellent properties are suitable because they have the oil-retaining properties to retain absorbed oil between the fibers. Examples of hydrophobic synthetic resin fibers include polypropylene fibers and polyethylene fibers. Synthetic resin fibers such as nylon fibers, natural fibers, and semi-synthetic fibers such as acetate can also be used, but because they are hydrophilic, they can be used by applying a water-repellent treatment to the fibers or fabric. Silicone-based water-repellent agents and fluorine-based water-repellent agents are known, and since fluorine-based treatment agents have both water-repellent and oil-repellent properties, silicone-based water-repellent agents are suitable. The oil-absorbing layer 18 is made of a high-density polyethylene nonwoven fabric (Tyvek 1056DR (trade name) manufactured by Asahi DuPont Flash Spun Products Co., Ltd., basis weight 54 g / m 2 ) can be preferably used.

[0035] The oil absorbing layer 18 may be colored by printing, etc. For example, the oil absorbing layer 18 and the release paper adhesive layer 22 side may be colored by printing in blue.

[0036] 1(a) and (b-1) to (b-2), the lower surface of the colored layer 16 and the upper surface of the oil-absorbing layer 18 are joined via a lipophilic first hydrophobic adhesive layer 20. Because the first hydrophobic adhesive layer 20 is lipophilic, oil absorbed in the oil-absorbing layer 18 can permeate the colored layer 16. Examples of adhesives that can form such a first hydrophobic adhesive layer 20 include rubber-based adhesives, acrylic-based adhesives, silicone-based adhesives, polyvinyl-based adhesives, polyurethane-based adhesives, and composite adhesives thereof.

[0037] Preferably, at least a portion of the oil absorbing layer 18 of the oil leak detection material 10, for example, the side surface of the oil absorbing layer 18 as shown in FIG. 1(b), is exposed, allowing leaked oil to come into direct contact with the oil absorbing layer 18, be rapidly absorbed by the oil absorbing layer 18, and penetrate into the colored layer 16 and the white layer 14. In the oil leak detection material 10 shown in FIG. 1, the underside of the oil absorbing layer 18 is covered with a release paper 24 via a release paper adhesive layer 22. By peeling off the release paper 24, the oil leak detection material 10 can be attached to an object to be detected for oil leaks, such as a flange, via the release paper adhesive layer 22. The release paper adhesive layer 22 is also formed from a lipophilic and hydrophobic adhesive, allowing leaked oil to penetrate from the release paper adhesive layer 22 into the oil absorbing layer 18. Furthermore, it is preferable that the adhesive layer 22 for the release paper is also formed from the same lipophilic and hydrophobic adhesive as the first hydrophobic adhesive layer 20, specifically, a rubber-based adhesive, an acrylic-based adhesive, a silicone-based adhesive, a polyvinyl-based adhesive, a polyurethane-based adhesive, or a composite adhesive thereof.

[0038] 1(a) and (b-1) shows an oil leak detection material 10 in which an oil-philic first hydrophobic adhesive layer 20 is formed on one side of an oil-absorbing layer 18, a release adhesive layer 22 is formed on the other side of the oil-absorbing layer 18, and then a colored layer 16 and a white layer 14 are laminated on the first hydrophobic adhesive layer 20 to form a laminated piece 17. The laminated pieces 17 are then arranged in a row at predetermined intervals, and the top surface of the white layer 14 and the side surfaces of the colored layer 16 and the white layer 14 are covered with a transparent protective layer 12. Thereafter, release paper 24 is attached to the release paper adhesive layer 22, and through holes 11 are opened between the laminated pieces 17 with a hole punch, thereby obtaining the oil leak detection material. The oil leakage detection material 10 shown in FIGS. 1(a) and (b-2) can be obtained in the same manner except that an oil absorption layer 18 having a large number of permeation holes 19 is used.

[0039] 1(a) and (b-1) to (b-2) can be attached to a predetermined location on a flange or other object to be detected for oil leaks by peeling off the release paper 24 and pressing the exposed release paper adhesive layer 22 against the material. When the attached oil leak detection material 10 is not in contact with water or leaking oil, only the white color of the white layer 14 is visible through the protective layer 12, as shown in FIG. 1(a), and the hue of the colored layer 16 is not visible. This is presumably because there is a large difference in refractive index between the white particles or white powder dispersed in the white layer 14 and the air in the microspace surrounding the white particles or white powder, and light that has passed through the white layer 14 is significantly bent and dispersed at the boundary between the white particles or white powder and the microspace.

[0040] On the other hand, when leaked oil comes into contact with the attached oil leak detection material 10, the first hydrophobic adhesive layer 20 and the oil-absorbing layer 18 are lipophilic, and the leaked oil penetrates the oil-absorbing layer 18 and the first hydrophobic adhesive layer 20 from the exposed side surface of the oil-absorbing layer 18, and then penetrates the colored layer 16 and the white layer 14. When the leaked oil penetrates the white layer 14, the white layer 14 becomes transparent or translucent, allowing the hue of the colored layer 16 to be visually recognized, as shown in Figure 2. The difference in refractive index between the leaked oil that penetrates the white layer 14 by capillary action or other factors and fills the microspaces surrounding the white particles or white powder and the white particles or white powder is smaller than the difference in refractive index between air and the white particles or white powder, and light that has passed through the white layer 14 can pass through without being significantly bent at the boundary between the white particles or white powder and the leaked oil in the microspace. For this reason, it is preferable to select white powder or white particles so that the difference in refractive index between the white particles or white powder and the oil to be detected is 0.1 or less.

[0041] Furthermore, even if water such as rainwater comes into contact with the attached oil leak detection material 10, the protective layer 12, the first hydrophobic adhesive layer 20, and the oil absorbing layer 18 are hydrophobic or water-repellent, so that the water cannot penetrate into the colored layer 16 and the white layer 14 that are surrounded by these, thereby avoiding discoloration due to water penetration into the colored layer 16 and the white layer 14. Furthermore, even if water does not penetrate into the protective layer 12, the first hydrophobic adhesive layer 20, and the oil absorbing layer 18 and the surface of the oil leak detection material 10 is wet, when leaked oil comes into contact with the exposed side surface of the oil absorbing layer 18, the leaked oil is immediately absorbed into the oil absorbing layer 18, making the white layer 14 transparent or translucent, and the hue of the colored layer 16 can be seen from the protective layer 12. Even if leaked oil and water come into contact with the exposed side surface of the oil absorbing layer 18 at the same time, only the leaked oil is selectively absorbed by the oil absorbing layer 18. Moreover, since water flows out of the oil leakage detection material 10 through the through holes 11, it is possible to prevent the material from becoming weak in adhesion, peeling off and falling off, or floating up and becoming unable to come into contact with the leaked oil.

[0042] 1(a) and 1(b-1) to 1(b-2) , even if oil leaks from the underside of the release paper adhesive layer 22 that attaches the oil leak detection material 10 to a flange or the like, by forming the release paper adhesive layer 22 with a hydrophobic and lipophilic adhesive, the leaked oil is absorbed into the oil absorbing layer 18 via the release paper adhesive layer 22. In this way, the leaked oil absorbed in the oil absorbing layer 18 is retained within the oil absorbing layer 18, and therefore, it is possible to prevent the oil leaking from the flange or the like from immediately flowing out onto the ground or the like.

[0043] 1(a), (b-1) to (b-2), and 2, the colored layer 16 and the white layer 14 are bonded to the oil-absorbing layer 18 via a first hydrophobic adhesive layer 20, and the upper surface of the white layer 14 and the side surfaces of the laminated piece 17 consisting of the white layer 14 and the colored layer 16 are covered by a protective layer 12. Alternatively, as shown in FIG. 3, the white layer 14 and the colored layer 16 may be placed directly on one surface of the protective layer 12, and the protective layer 12 may be bonded to the upper surface of the white layer 14 and the side surfaces of the white layer 14 and the colored layer 16 via a lipophilic second hydrophobic adhesive layer 26. The second hydrophobic adhesive layer 26 is preferably formed from a hydrophobic adhesive, such as a rubber-based adhesive, an acrylic-based adhesive, a silicone-based adhesive, a polyvinyl-based adhesive, a polyurethane-based adhesive, or a composite adhesive thereof.

[0044] In addition, as shown in Figure 4, the oil leak detection material 10 may have the white layer 14 and the colored layer 16 placed directly on one surface of the protective layer 12, and the upper surface of the white layer 14 and the side surfaces of the white layer 14 and the colored layer 16 may be directly covered by the protective layer 12.

[0045] Another embodiment of the oil leak detection device 10, as shown in FIG. 5, has a structure similar to that shown in FIGS. 1 to 4, except that the colored layer 16 is covered with a slightly larger white layer 14 to form a laminated piece 17, a second hydrophobic adhesive layer is provided around the laminated piece 17 with a gap therebetween so as not to come into contact with the laminated piece 17, and the oil-absorbing layer 18 and the protective layer 12 are adhered by the second hydrophobic adhesive layer 26. The laminated piece 17 is sandwiched between the oil-absorbing layer 18 and the protective layer 12, making it difficult for the layer to move due to friction. Generally, adhesive components in adhesive layers are easily degraded by ultraviolet light. Therefore, if the second hydrophobic adhesive layer 26 deteriorates while in contact with the white layer 14, the components of the second hydrophobic adhesive layer 26 may migrate to the white layer 14, causing the white layer 14 to easily discolor even when exposed to water. This may lead to sensitivity to water and a decrease in water resistance. Therefore, by avoiding contact of the second hydrophobic adhesive layer 26 with the white layer 14 and attaching it to the top surface of the white layer 14, and instead attaching it so as to surround the white layer 14, it is possible to prevent a decrease in water resistance due to deterioration of the second hydrophobic adhesive layer 26.

[0046] 1 and 2, the colored layer 16 and white layer 14 are rectangular, but they may also be circular, as shown in Fig. 6. When the oil leak detection material 10 is not in contact with leaked oil, the hue of the colored layer 16 is not visible from the protective layer 12 due to the white layer 14, as shown in Fig. 6(a). However, when the oil leak detection material 10 comes into contact with leaked oil, the white layer 14 becomes transparent or semi-transparent, and the hue of the colored layer 16 can be seen from the protective layer 12, as shown in Fig. 6(b). The shapes of the white layer 14 and the colored layer 16 can be any shape, such as letters, symbols, etc., in addition to various shapes such as rectangles and circles. For example, the white layer 14 itself can be shaped like letters indicating oil leakage, such as "oil," so that the letters stand out due to the oil leakage and are displayed, or conversely, the white layer 14 can be designed so that the letters are not displayed, or the colored layer 16 can be shaped like letters, symbols, etc., so that they can be displayed or not displayed. For example, taking the case where the colored layer 16 itself is shaped like letters indicating an oil leak, when there is no oil leak the letters are hidden by the white layer 14 and are not visible, but when oil leaks the white layer 14 becomes transparent or semi-transparent and the letters of the colored layer 16 are revealed and are visible as if they are floating above the protective layer 12. On the other hand, taking the case where the white layer 14 itself is shaped like letters indicating an oil leak as an example, when there is no oil leak the colored layer 16 is visible in the non-letter-shaped parts of the white layer 14 and the letter shapes hide the colored layer 16, so the letters appear visible, but when oil leaks the white layer 14 becomes transparent or semi-transparent and no longer hides the colored layer 16, so the letters become invisible and appear not to be displayed.

[0047] 1 to 6, the oil leakage detection material 10 has been described as having a rectangular through-hole 11, but it may also be tape- or strip-shaped as shown in Fig. 7(a). An example has been shown in which a single through-hole 11 is formed between adjacent laminated pieces 17 in the shape of a rounded rectangle, but it may also be formed so that a plurality of circular through-holes 11 are formed as shown in Fig. 7(b).

[0048] This oil leak detection material 10 is attached to an object where oil leaks must be detected. For example, referring to Figure 8, this oil leak detection material 10 is attached to a flange with grooves on its outer periphery. This oil leak detection material 10 is attached to the underside of a flange 30, where oil is likely to accumulate due to a leak. When oil leaks from the flange 30, the leaked oil 33 drips down the flange through the grooves 31. The leaked oil 33 is absorbed by the oil-absorbing layer 18 of the oil leak detection material 10 attached under the flange, penetrates the colored layer 16 and white layer 14, and eventually the white layer 14 becomes transparent or translucent, revealing the colored layer 16 and making the leak visible. In this case, when water drips down the flange along the grooves 31 with the leaked oil, the oil is absorbed by the oil-absorbing layer 18, but the water is not absorbed by the oil-absorbing layer 18 and is naturally discharged by gravity through the through-holes 11 to the outside of the oil leak detection material 10.

[0049] 1 to 8 can be easily attached to locations such as flanges where oil leakage is likely, and can reliably detect the presence of an oil leak only when leaked oil alone or a water-oil mixture containing water and leaked oil comes into contact with the oil leak detection material 10. In addition, leaked oil can be temporarily retained within the oil absorption layer 18, preventing the leaked oil from immediately flowing out onto the ground, etc. [Example]

[0050] Examples of the present invention will be described in detail below, but the scope of the present invention is not limited to these examples.

[0051] Example 1 The oil leak detection material 10 shown in Figure 1 was fabricated. First, a white ink was prepared by kneading 30 parts by mass of stearic acid (refractive index 1.43) as a white powder, 5 parts by mass of transparent ethyl cellulose resin, and 65 parts by mass of xylene. This white ink was applied to one side of black-colored wood-free paper serving as the colored layer 16 using a coater applicator to a thickness of 150 μm, and then dried to form the white layer 14. Next, the substrate with the white layer 14 formed on one side of the colored layer 16 was cut into a 40 mm x 40 mm square. In addition, a polyethylene nonwoven fabric (Tyvek 1056DR (trade name) manufactured by Asahi DuPont Flash Spun Products Co., Ltd., basis weight 54 g / m) was used as the oil absorption layer 18. 2 An oil-permeable acrylic adhesive was applied to both sides of the sheet to form a first hydrophobic adhesive layer 20 and an adhesive layer 22 for release paper, and the sheet was then cut into a 50 mm x 50 mm square. The cut colored layer 16 was formed into laminated pieces 17, with the white layer 14 facing up, and multiple pieces were attached in a row to the center of the cut first hydrophobic adhesive layer 20. Furthermore, a 50 mm × 50 mm transparent polyethylene terephthalate film was attached as a protective layer 12 so as to cover the top surface of the white layer 14 and the side surfaces of the white layer 14 and colored layer 16. Thereafter, a 50 mm × 50 mm release paper 24 was attached to the release paper adhesive layer 22, and finally, a 3 mm × 15 mm hole was punched between adjacent laminated pieces 17 with a cutter to obtain the oil leak detection material 10 shown in Figure 1. In the obtained oil leak detection material 10, the hue of the colored layer 16 cannot be seen from the protective layer 12 due to the opaque white layer 14.

[0052] (Comparative Example 1) Type A white ink was prepared according to Example 1 described in Japanese Patent No. 6609085. Type A white ink was prepared by kneading 18 parts by weight of talc (refractive index 1.54) as a white powder with 25 parts by weight of a transparent resin solution containing 8% ethyl cellulose in a medium. This white ink was applied to one side of a black-colored polypropylene nonwoven fabric as a colored layer using a coater applicator to a thickness of 200 μm and then dried. A fluororesin coating agent was then applied to the top surface and dried to form a transparent protective layer. An acrylic adhesive was attached to the other side of the colored layer as an adhesive layer, and the resulting material was cut to a 50 mm x 50 mm size to obtain an oil leak detection material. The opaque white layer made the colored layer invisible through the protective layer.

[0053] Example 2 The oil leak detection material 10 obtained in Example 1 and the oil leak detection material obtained in Comparative Example 1 were each attached to an aluminum plate to prepare a test specimen. The color density of the white layer visible through the protective layer of this test specimen was measured. This test specimen was immersed in a tray containing water (refractive index 1.33), silicone oil (refractive index 1.44), or hydraulic oil (refractive index 1.5) for 2 hours, and then the color density of the white layer visible through the protective layer was measured. The color density was measured using a densitometer (trade name X-Rite 504, manufactured by X-Rite) to measure the visual density of the shades. The color density of the colored layer itself was also measured. The measurement results are shown in Table 1 below.

[0054] [Table 1]

[0055] As is clear from Table 1, the oil leak detection material of Example 1 was not affected by water wetting, with no difference in the color density of the white layer before wetting and after wetting with water. Furthermore, the color density of the white layer after wetting with silicone oil and hydraulic oil increased significantly, and the color changed clearly with both silicone oil and hydraulic oil, making it possible to visually confirm oil wetting. On the other hand, the color density of the white layer of the oil leak detection material of Comparative Example 1 increased after wetting with water compared to the color density of the white layer before wetting, making it easy to mistake it for oil wetting. Also, the color density of the white layer after wetting with silicone oil was smaller than the color density of the colored layer itself, and was actually closer to the color density of the white layer after wetting with water, making it difficult to determine whether it was oil wetting or not.

[0056] Example 3 (material) A white ink for the white layer 14 was prepared by kneading 30 parts by mass of calcium stearate (refractive index 1.46) as a white powder, 5 parts by mass of a transparent ethyl cellulose resin, and 65 parts by mass of xylene. A red ink for the colored layer 16 was prepared by kneading 30 parts by mass of red iron oxide as a red pigment, 5 parts by mass of a transparent ethyl cellulose resin, and 65 parts by mass of xylene. Polyethylene nonwoven fabric (Tyvek 1056DR (trade name) manufactured by Asahi DuPont Flash Spun Products Co., Ltd., basis weight 54 g / m 2 ) was used as the oil absorbing layer 18. The protective layer 12 was made of a polyester film. The second hydrophobic adhesive layer 26 was made of an acrylic adhesive. An acrylic adhesive was used as the adhesive layer 22 for the release paper. Release paper 24 was prepared.

[0057] (Production) The oil leak detection material 10 was fabricated as follows. Red ink was applied by screen printing to one side of the oil-absorbing layer 18 (250 × 35 mm) to form seven colored layers 16 (18 × 18 mm, evenly spaced). White ink was applied by screen printing to the upper surface of the colored layer 16 to form seven white layers 14 (20 × 20 mm, evenly spaced). Gaps 27 were created around the periphery of the white layer 14, and a second hydrophobic adhesive layer 26 (250 × 35 mm) was attached, and a protective layer 12 (250 × 35 mm) was attached on top of that. A release paper adhesive layer 22 and release paper 24 (250 × 35 mm) were attached to the opposite side of the oil-absorbing layer 18. Punched through holes (3 × 15 mm) were opened using a cutter at the gaps between the white layer 14 and the colored layer 16 to obtain the oil leak detection material 10 shown in Figure 5.

[0058] (Evaluation test for discoloration due to oil leakage) The oil leak detection material 10 of Example 3 was attached so as to straddle the groove 31 at the lower connection portion of a JIS 10K 100A flange 30 serving as the target for oil leak detection (see FIG. 8). To simulate an oil leak 33 from the flange 30, 5 mL of hydraulic oil (refractive index 1.5) was poured into the connection portion of the flange 30. As a result, it was confirmed that the hydraulic oil passed through the through-hole 11 from the rear side of the oil leak detection material 10 and flowed to the front side of the oil leak detection material 10. After that, the white layer 14 visible through the protective layer 12 of this oil leak detection material 10 began to change color to red within 3 hours, indicating the presence of an oil leak. For reference, when a test was conducted under the same conditions on a specimen without through holes in Example 3, discoloration began in 12 hours, and although oil leakage was detected, the discoloration was slow. This is because the oil-absorbing layer was not exposed to much light, and it took time for oil from the back side to penetrate the oil-absorbing layer.

[0059] (Rainwater discharge performance evaluation test) The oil leak detection material 10 of Example 3 was attached so as to straddle the groove 31 at the lower connection part of a JIS 10K 100A flange 30 as the target for oil leak detection (see FIG. 8). To simulate rainwater falling on the flange 30, 100 mL of water was poured into the connection part of the flange. As a result, it was confirmed that water passed through the through-hole 11 from the back side of the oil leak detection material 10 and was discharged to the front side of the oil leak detection material 10. For reference, when a test was conducted under the same conditions on a specimen in Example 3 that did not have a through hole, water was not discharged and remained between the flange connection and the Example.

[0060] (Weather resistance performance evaluation test) The oil leak detection material 10 of Example 3 was attached to an aluminum plate and subjected to a xenon weather meter test (60 W / m 2 A weather resistance test was conducted for 400 hours under the conditions of UV (300-400 nm), BPT 63°C, and spray (18 min / 120 min). As a result, it was confirmed that the color tone of the white layer 14 visible through the protective layer 12 of the oil leak detection material 10 remained white and did not change. For reference, when a test was conducted under the same conditions on a similar specimen to Example 3 except that the second hydrophobic adhesive layer extended up to the top surface of the white layer, the white layer visible through the protective layer turned light red. This was because the second hydrophobic adhesive layer had deteriorated due to ultraviolet light, affecting the white layer.

[0061] As described above, the oil leak detection material 10 to which the present invention is applied can reliably detect oil leaks with high sensitivity and quickly in a short time. Furthermore, even if the oil leak detection material gets wet with water such as rainwater, false detection can be prevented. [Industrial Applicability]

[0062] The oil leak detection material of the present invention does not discolor due to rainwater alone, and can reliably detect oil leaks even with silicone oil, which has a refractive index close to that of water, and can detect oil leaks from various oil tanks, piping flanges, etc. [Explanation of symbols]

[0063] 10: Oil leakage detection material; 11: Through hole; 12: Protective layer; 14: White layer; 16: Colored layer; 17: Laminated sheet; 18: Oil-absorbing layer; 19: Through hole; 20: First water-based adhesive layer; 22: Release paper adhesive layer; 24: Release paper; 26: Second water-based adhesive layer; 27: Gap; 30: Flange; 31: Groove; 32: Water; 33: Oil leakage.

Claims

1. An oil leakage detection material comprising: a colored layer colored in a predetermined color and having oil-absorbing properties; a white layer having oil-absorbing properties, which is laminated in contact with at least a part of the upper surface of the colored layer and in which white particles or white powder are contained or attached to a transparent resin layer; a protective layer made of a transparent hydrophobic resin and provided so as to cover the upper surface of the white layer; and an oil-absorbing layer, which is provided on the lower surface side of the colored layer and has oil-absorbing and oil-retaining properties and is formed of a material having water repellency or has been subjected to a water repellent treatment, and a plurality of laminated pieces of the colored layer and the white layer are arranged, Between adjacent laminated pieces, through-holes leading from the outside to the oil-absorbing layer are formed, the colored layer and the white layer are sandwiched between the protective layer and the oil absorbing layer so as to prevent water from penetrating into the colored layer and the white layer, and the difference in refractive index between oil, which is an object of oil leakage detection and has a refractive index of 1.40 to 1.55, and the white particles or white powder is 0.1 or less; When leaked oil or leaked oil and water come into contact with at least a portion of the surface of the oil absorption layer, only the leaked oil is absorbed by the oil absorption layer and penetrates into the colored layer and the white layer, the white layer becomes transparent or translucent, and the hue of the colored layer can be seen visually through the protective layer.

2. The oil leak detection material described in claim 1, characterized in that the through holes penetrate the oil leak detection material together with the oil absorption layer between adjacent laminated pieces, thereby bringing at least a portion of the oil absorption layer into direct contact with the leaked oil or the leaked oil and water.

3. 2. The oil leak detector according to claim 1, wherein the oil absorbing layer has one or more through holes facing the laminated piece.

4. 2. The oil leakage detection material according to claim 1, wherein one or more through holes are formed between adjacent laminated pieces.

5. 2. The oil leakage detector according to claim 1, wherein the through-hole has a shape selected from the group consisting of a circle, an ellipse, a rectangle, and a rectangle with rounded corners.

6. 2. The oil leak detector according to claim 1, wherein the oil absorbing layer is made of a hydrophobic synthetic resin fiber and is a fabric that exhibits water repellency.

7. The oil leak detection material described in claim 1, characterized in that the oil absorption layer and the colored layer are joined via an oil-philic first hydrophobic adhesive layer, and the colored layer and the white layer are sandwiched between the protective layer and the first hydrophobic adhesive layer.

8. The oil leak detection material described in claim 1, characterized in that the protective layer and the white layer are joined via a transparent second hydrophobic adhesive layer, and the white layer and the colored layer are sandwiched between the second hydrophobic adhesive layer and the oil absorption layer.

9. The oil leak detection material described in claim 1, characterized in that a transparent second hydrophobic adhesive layer is arranged around the white layer and the colored layer with a gap, and the protective layer and the oil absorption layer are joined via the second hydrophobic adhesive layer while sandwiching the white layer and the colored layer.

10. 2. The oil leak detector according to claim 1, wherein the colored layer is any color selected from the group consisting of black, navy blue, red, orange, blue, green, brown, and purple.

11. The oil leak detection material described in claim 1, characterized in that the colored layer and / or the white layer are shaped in the shape of letters, symbols, and / or graphics, or the colored layer is printed in the shape of letters, symbols, and / or graphics.

12. 2. The oil leakage detection material according to claim 1, wherein the particle size of the white particles or white powder is 20 μm or less.

13. 2. The oil leakage detection material according to claim 1, wherein the white particles or white powder is selected from the group consisting of organic compounds, plastic powders, metal salts, glass beads, and glass fillers.

Images