Pressure measuring materials

Abstract

To provide a novel pressure measuring material that is easy to manufacture, manage, and operate. [Solution] The pressure measuring material 1 includes a graphite sheet 10, and utilizes the properties of the graphite sheet, which change thickness according to the magnitude of the applied pressure and maintain that thickness even after the pressure is released. When one side of the graphite sheet 10 is pressurized according to the pressure distribution of the object to be measured, and then this pressurization is removed, a thickness distribution is created on the surface of the graphite sheet 10 corresponding to the pressure distribution of the object to be measured. As a result, the thickness of each part of the graphite sheet 10 can be easily determined by measurement or visual inspection, making it easy to measure the pressure distribution and the like.

Description

Technical Field

[0001] The present disclosure relates to pressure measurement materials, and more particularly to pressure measurement materials suitable for measuring pressure distribution and the like.

Background Art

[0002] Conventionally, in various scenarios, pressure and pressure distribution have been measured, and various members and materials for use in such measurements have been studied.

[0003] Patent Document 1 discloses a pressure-sensitive foil. This pressure-sensitive foil is composed of a first thin film having uneven surfaces that cause plastic deformation on only one side, a relatively hard second thin film provided on both surface sides of the first thin film, and a third thin film for lubrication interposed between the first thin film and the second thin film.

[0004] Patent Document 2 discloses a pressure measurement material. This pressure measurement material utilizes a color development reaction between an electron-donating colorless dye precursor and an electron-accepting compound, and the color density difference ΔD before and after pressurization at 0.05 MPa is said to be 0.02 or more.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0006] Members such as those in Patent Document 1 and materials such as those in Patent Document 2 have complex shapes, structures, compositions, etc., so not only is their manufacturing complicated, but there is also the disadvantage that management and operations during use become complicated.

[0007] The objective of this disclosure is to provide a novel pressure measuring material that is easy to manufacture, manage, and operate. [Means for solving the problem]

[0008] A pressure measuring material according to one aspect of this disclosure includes a graphite sheet. [Effects of the Invention]

[0009] According to this disclosure, it is possible to provide a novel pressure measuring material that is easy to manufacture, manage, and operate. [Brief explanation of the drawing]

[0010] [Figure 1] Figure 1 is a schematic cross-sectional view illustrating a pressure measuring material according to the first embodiment of this disclosure. [Figure 2] Figure 2 is a schematic cross-sectional view illustrating a pressure measuring material according to a second embodiment of this disclosure. [Modes for carrying out the invention]

[0011] 1. Overview The following describes a pressure measuring material according to one embodiment of this disclosure. Note that the following embodiment is only one of many embodiments of this disclosure. The following embodiment can be modified in various ways depending on the design, as long as it achieves the objectives of this disclosure.

[0012] While diligently studying graphite sheets, the inventors discovered an unknown attribute of graphite sheets: "their thickness changes according to the magnitude of the applied pressure, and this thickness is maintained even after the pressure is released." They found that this attribute makes them suitable for use in a new application as a pressure measuring material, and thus completed this disclosure.

[0013] A "pressure measuring material" refers to a component suitable for use in pressure measurement applications. The pressure measuring material 1 according to this embodiment includes a graphite sheet 10. With this pressure measuring material 1, due to the attribute of the graphite sheet 10 described above, "its thickness changes according to the magnitude of the applied pressure, and its thickness is maintained even after the pressure is released," when one side of the graphite sheet 10 is pressurized according to the pressure distribution of the object to be measured, and then this pressurization is removed, a thickness distribution occurs on the surface of the graphite sheet 10 corresponding to the pressure distribution of the object to be measured. As a result, by determining the thickness of each part of the graphite sheet 10 by measurement or visual inspection, the pressure distribution can be easily measured.

[0014] The pressure measuring material 1 according to this embodiment can be easily manufactured because it uses a graphite sheet 10 as is or with slight processing. Furthermore, because its shape, structure, and composition are simple, it is easy to manage during use and has excellent workability. Thus, the pressure measuring material 1 is easy to manufacture, manage, and handle, significantly improving upon the complexity of manufacturing, management, and handling of conventional pressure measuring materials.

[0015] Furthermore, because the graphite sheet 10 of the pressure measuring material 1 has excellent heat resistance, chemical resistance, etc., it can be used in harsh environments where conventional pressure-sensitive paper (for example, Fujifilm's "Prescale®") could not be used, such as high-temperature environments and acidic environments.

[0016] Furthermore, with pressure measuring material 1, expensive equipment such as dedicated cameras and image analysis software, as used in conventional pressure measuring materials, is not required for detection during pressure measurement. Instead, pressure measurement becomes possible using inexpensive equipment such as a thickness measuring machine.

[0017] 2.Details Hereinafter, the pressure measurement material 1 according to the first and second embodiments will be described with reference to FIGS. 1 and 2. Each figure is a schematic diagram, and the ratio of the size and thickness of each component in each figure does not necessarily reflect the actual dimensional ratio.

[0018] [First Embodiment] The pressure measurement material 1 according to the first embodiment will be described with reference to FIG. 1.

[0019] As shown in FIG. 1, the pressure measurement material 1 according to the first embodiment is composed of a graphite sheet 10. That is, the pressure measurement material 1 according to the first embodiment is the graphite sheet 10 itself. The pressure measurement material 1 according to the first embodiment may further include other parts other than the graphite sheet 10 as long as the effects of the present disclosure are not impaired.

[0020] The principle by which pressure measurement can be performed using the pressure measurement material 1 will be described with reference to FIG. 1. In the pressure measurement material 1, in FIG. 1, by applying pressure to one surface of the graphite sheet 10 with the pressure distribution of the measurement object represented as a weight 100, that part is recessed and the thickness decreases according to the magnitude of the pressure. Even when this pressure application is stopped, the thickness of that part is maintained, so a thickness distribution is formed on the surface of the graphite sheet 10 corresponding to the pressure distribution of the measurement object. By grasping this thickness distribution by using a thickness measuring machine or the like for the thickness of each part or by visual observation, the pressure distribution or the like can be measured. Also, by grasping the relationship between the magnitude of the pressure and the thickness after pressure application as a calibration curve, the pressure distribution can be measured as a numerical value.

[0021] The "graphite sheet" refers to a sheet mainly composed of graphite. The "graphite" is graphite, which is a kind of allotrope of carbon. 2Layers (graphene layers) arranged in a hexagonal honeycomb lattice by bonding are bonded in a plurality of layers in the thickness direction by van der Waals forces. The "main component" refers to the component with the highest content rate, for example, a component with a content rate of 50% by mass or more, preferably 70% by mass or more, more preferably 90% by mass or more, and even more preferably 99% by mass or more. Further, the "sheet" means a molded body that is flat and has a small thickness relative to its length and width.

[0022] The planar shape of the graphite sheet 10 can be appropriately selected according to the measurement object, and examples include polygons such as rectangles, squares, and triangles, and circular shapes such as perfect circles and ellipses. The length and width of the rectangular graphite sheet 10 are not particularly limited, but for example, the length is 1 cm or more and 1 m or less, and the width is 1 cm or more and 30 cm or less. The average thickness of the graphite sheet 10 is, for example, 1 μm or more and 5 mm or less, and preferably 10 μm or more and 1 mm or less. The "average thickness" refers to the arithmetic mean value of the thicknesses measured at a plurality of points (for example, any 10 points) on the graphite sheet or the like.

[0023] The graphite sheet 10 can be manufactured, for example, by carbonizing a polymer film such as a polyimide film or a polymer film containing a filler to obtain a carbonized film and then firing it at about 2600 °C to graphitize it. Thus, the pressure measurement material 1 may be composed of a heat-treated product of a polymer film as the graphite sheet 10. In this case, the pressure measurement material 1 can be manufactured more easily.

[0024] The graphite sheet 10 manufactured in this way has dense layers on both surface layers. The dense layer is a region where the crystallization of graphite has progressed and it has become hard. The graphite sheet 10 can be used whether it has a dense layer or the dense layer is removed. Since the flexibility of the graphite sheet 10 changes depending on the presence or absence of the dense layer, the pressure measurement range of the pressure measurement material 1 can be adjusted.

[0025] The pressure measurement range of the pressure measuring material 1 can be set in various ways by adjusting the physical properties of the graphite sheet 10 used, but for example, it can be 50 kPa or more and 1000 kPa or less, or 100 kPa or more and 500 kPa or less. By setting the pressure measurement range of the pressure measuring material 1 in this way, it can be used more effectively for measuring pressure distribution and the like.

[0026] In pressure measurement using the pressure measuring material 1, in addition to the thickness mentioned above, other physical properties of the graphite sheet 10, such as density and porosity, can also be used.

[0027] [Second Embodiment] The pressure measuring material 1 according to the second embodiment will be described with reference to Figure 2. In the second embodiment, components similar to those in the first embodiment may be denoted by the same reference numerals as in the first embodiment, and detailed descriptions may be omitted.

[0028] The pressure measuring material 1 according to the second embodiment differs from the pressure measuring material 1 according to the first embodiment in that a transparent film 20 is attached to at least one surface of the graphite sheet 10 via an adhesive layer 30.

[0029] As shown in Figure 2, the pressure measuring material 1 according to the second embodiment has a transparent film 20 attached to at least one side of a graphite sheet 10 via an adhesive layer 30. In other words, the pressure measuring material 1 according to the second embodiment comprises a graphite sheet 10, an adhesive layer 30 directly laminated to at least one side of the graphite sheet 10, and a transparent film 20 directly laminated to the side of the adhesive layer 30 opposite to the graphite sheet 10. The pressure measuring material 1 according to the second embodiment may further include other parts other than the graphite sheet 10, the transparent film 20, and the adhesive layer 30, to the extent that it does not impair the effects of the present disclosure.

[0030] In addition to being easy to manufacture, manage, and operate as described above, the pressure measuring material 1 according to the second embodiment has the effect of making it easier to visually grasp the pressure distribution and the like.

[0031] This effect is illustrated in Figure 2. The graphite sheet 10 typically has an uneven surface. Therefore, when the surface of the graphite sheet 10 is viewed from the transparent film 20 side, the unevenness of the graphite sheet 10 and the gaps between it and the adhesive layer 30 cause light to scatter, making it appear bright (whitish). Note that in Figure 2, the unevenness of one side of the graphite sheet 10 is exaggerated for ease of understanding.

[0032] As shown in Figure 2, when pressure is applied to one side of the graphite sheet 10 of the pressure measuring material 1 by the pressure distribution of the object to be measured, indicated by a weight 100, that part becomes indented, and the thickness decreases in proportion to the magnitude of the pressure. Even after the pressure is stopped, the thickness of that part is maintained.

[0033] Furthermore, as shown in Figure 2, in areas pressurized by the pressure distribution of the object to be measured, indicated by the weight 100, the irregularities of the graphite sheet 10 bite into the adhesive layer 30, eliminating the gap between the graphite sheet 10 and the adhesive layer 30. As a result, the diffuse reflection of light in these areas decreases, making them appear darker (blackish). Thus, according to the pressure measuring material 1 of the second embodiment, a difference in brightness is produced depending on the magnitude of the pressure, making it easy to visually grasp the pressure distribution and the like.

[0034] The graphite sheet 10 in the pressure measuring material 1 according to the second embodiment can be the same as that in the pressure measuring material 1 according to the first embodiment, and may have a dense layer or have the dense layer removed.

[0035] A "transparent film" refers to a film with a total light transmittance of 85% or more, measured in accordance with JIS K-7361-1, at a thickness of 40 μm, or a light transmittance of 85% or more at 600 nm and 400 nm. It is preferable to use a transparent film 20 with a haze value of 5% or less, measured in accordance with JIS K-7136.

[0036] Examples of materials for the transparent film 20 include polyethylene terephthalate (PET), polypropylene (PP), and polyamide.

[0037] The average thickness of the transparent film 20 is, for example, 10 μm or more and 100 μm or less, and preferably 20 μm or more and 80 μm or less.

[0038] The adhesive layer 30 can be any material capable of conforming to the unevenness of the graphite sheet 10 when pressurized. For example, it can be a semi-solid, viscous material that is not yet solidified.

[0039] As the adhesive for forming the adhesive layer 30, well-known adhesives such as acrylic adhesives, silicone adhesives, urethane adhesives, and rubber adhesives can be used.

[0040] The average thickness of the adhesive layer 30 is, for example, 1 μm or more and 50 μm or less, and preferably 2 μm or more and 20 μm or less.

[0041] In the pressure measuring material 1, the transparent film 20 may be provided on only one side of the graphite sheet 10 or on both sides, but from the viewpoint of improving the measurement sensitivity of the pressure measuring material 1, it is preferable that it be provided on only one side (the side opposite to the measurement surface).

[0042] Thus, according to the pressure measuring material 1 of the second embodiment, it becomes easier to visually grasp the pressure distribution and the like.

[0043] 3. Appearance As is clear from the embodiments described above, this disclosure includes the following aspects. In the following, reference numerals are enclosed in parentheses solely to indicate their correspondence with the embodiments.

[0044] The pressure measuring material (1) of the first embodiment includes a graphite sheet (10).

[0045] According to the first embodiment, the pressure measuring material (1) is easy to manufacture, manage, and operate.

[0046] In the second embodiment of the pressure measuring material (1), a transparent film (20) is attached to at least one surface of the graphite sheet (10) via an adhesive layer (30), as in the first embodiment.

[0047] According to the second embodiment, the pressure measuring material (1) is easy to manufacture, manage, and operate, and it is easier to visually grasp the pressure distribution, etc.

[0048] In the third embodiment of the pressure measuring material (1), the graphite sheet (10) is made of a heat-treated polymer film, as in the first or second embodiment.

[0049] According to the third embodiment, the pressure measuring material (1) can be manufactured more easily.

[0050] In the pressure measuring material (1) of the fourth embodiment, in any one of the first to third embodiments, the pressure measuring range is 50 kPa or more and 1000 kPa or less.

[0051] According to the fourth embodiment, the pressure measuring material (1) can be suitably used by measuring pressure distribution and the like. [Explanation of Symbols]

[0052] 1. Materials for measuring pressure 10 Graphite Sheets 20 Transparent film 30 Adhesive layer

Claims

1. Pressure measuring material including graphite sheet.

2. A transparent film is attached to at least one surface of the graphite sheet via an adhesive layer. The pressure measuring material according to claim 1.

3. The graphite sheet is composed of a heat-treated polymer film. A pressure measuring material according to claim 1 or 2.

4. The pressure measurement range is between 50 kPa and 1000 kPa. A pressure measuring material according to claim 1 or 2.

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