Water detecting device, water detecting system, resin composition for water detecting device, and method for manufacturing water detecting device

Abstract

Provided is a water detecting device that allows the location of a water leak to be easily identified even after the passage of time. A water detecting device 1 is attached to an object, and detects water. The water detecting device 1 includes: a substrate 2; a wiring pattern 3 which is formed on either of one surface in the thickness direction of the substrate 2 or the other surface in the thickness direction of the substrate 2; and terminals 4 which are electrically connected to the wiring pattern 3 and to which a power supply is connected. The substrate 2 includes plate-like water-soluble resin portions 22 of which one surface in the thickness direction is exposed to one side in the thickness direction of the substrate 2 and the other surface in the thickness direction is exposed to the other side in the thickness direction of the substrate 2. At least a portion of the wiring pattern 3 is formed on each water-soluble resin portion 22.

Description

Water detection device, water detection system, resin composition for water detection device, and method for manufacturing water detection device

[0001] The present invention relates to a water detection device for detecting water.

[0002] Water detection devices that detect water based on changes in electrical properties are known. Patent Document 1 discloses a water wetting sensor, which is an example of such a water detection device. The water wetting sensor includes an IC tag with a circuit configured to interrupt at least a portion of the circuit when the IC tag comes into contact with water. In the water wetting sensor, at least a portion of the circuit is formed on a second substrate containing a water-soluble component that is formed on a water-insoluble substrate. At least a portion of the circuit formed on the second substrate is interrupted by dissolution of the circuit on the substrate.

[0003] Furthermore, Patent Document 2 discloses a moisture detection component that has an antenna portion and detects the occurrence of moisture by utilizing a change in the electrical characteristics of the antenna portion when moisture adheres to an area facing the antenna portion. Patent Document 2 discloses that the moisture detection component can be attached to a pipe or the like and can detect water leakage from the pipe or the like.

[0004] JP 2021-067660 A JP 2019-124657 A

[0005] In the water leak sensor of Patent Document 1, the second substrate on which the circuit is formed is applied to the water-insoluble substrate. That is, in the water leak sensor, the second substrate and the circuit are supported by the water-insoluble substrate. Therefore, the water leak sensor cannot detect water on the structure side where the water leak sensor is installed, for example, water leakage from the structure.

[0006] The moisture detection element of Patent Document 2 can detect water leakage in a structure. However, when the moisture evaporates over time, the moisture detection element returns to a state where no moisture is present. Therefore, it may not be possible to identify the location of the leakage over time.

[0007] In response to this, there is a demand for a configuration that can detect water leakage from a structure and identify the location of the leakage even after the passage of time.

[0008] An object of the present invention is to provide a water detection device that can easily identify the location of a water leak even after a period of time has passed.

[0009] A water detection device according to one embodiment of the present invention is a water detection device that is attached to an object and detects water. This water detection device includes a substrate, a wiring pattern formed on either one surface or the other surface of the substrate in the thickness direction, and a terminal that is electrically connected to the wiring pattern and to which a power source is connected. The substrate includes a plate-shaped water-soluble resin part whose one surface in the thickness direction is exposed to one side of the substrate in the thickness direction and whose other surface in the thickness direction is exposed to the other side of the substrate in the thickness direction. At least a portion of the wiring pattern is formed on the water-soluble resin part (first configuration).

[0010] In the above-described configuration, the water-soluble resin portion dissolves when it comes into contact with water. Therefore, when water inside an object to which a water detection device is attached leaks to the surface, a portion of the substrate dissolves. This physically changes the state of a portion of the wiring pattern formed in the dissolved portion of the substrate. This changes the value of the current flowing through the wiring pattern when power is supplied to the wiring pattern from the terminal. Therefore, water can be detected based on the change in the current value.

[0011] Furthermore, with the above-described configuration, the portion of the substrate that comes into contact with water dissolves. This allows the location of the water leak to be identified even after the passage of time. Therefore, a water detection device that can easily identify the location of the water leak even after the passage of time can be provided.

[0012] In the first configuration, the wiring pattern includes a first wiring pattern at least a portion of which is formed on the water-soluble resin portion of the substrate, and a second wiring pattern formed on the substrate other than on the water-soluble resin portion and electrically connected to the first wiring pattern. The first wiring pattern is disconnected by dissolving the portion of the water-soluble resin portion where the first wiring pattern is formed (second configuration).

[0013] This allows for a configuration in which the current flowing through the wiring pattern decreases when the water-soluble resin dissolves, providing a water detection device that can detect water based on changes in the current and easily identify the location of a leak even after a period of time has passed.

[0014] In the first configuration, the wiring pattern includes a first wiring pattern at least a portion of which is formed on the water-soluble resin portion of the substrate, and a second wiring pattern formed on a portion of the substrate other than the water-soluble resin portion, and at least a portion of the portion of the first wiring pattern formed on the water-soluble resin portion is positioned so as to overlap a portion of the second wiring pattern when viewed in the thickness direction, and the water-soluble resin portion dissolves and comes into electrical contact with the portion of the second wiring pattern, thereby electrically connecting to the second wiring pattern (third configuration).

[0015] This allows a configuration in which a current flows through the wiring pattern when the water-soluble resin dissolves, thereby providing a water detection device that can detect water by changes in the current value and easily identify the location of a water leak even after a period of time has passed.

[0016] In the first configuration, the water detection device further includes a mounting portion that mounts the other surface of the substrate opposite to the one surface along the surface of the object (fourth configuration).

[0017] This allows the water detection device to be attached to the object, thereby providing a water detection device that can be easily attached to the object.

[0018] In the fourth configuration, the attachment portion is an adhesive layer laminated on at least a part of the other surface of the substrate (fifth configuration).

[0019] This allows the water detection device to be attached to the object, making it easy to attach the water detection device to the object.

[0020] In the fifth configuration, the water detection device further includes a cover layer that covers the one surface of the substrate (sixth configuration).

[0021] This makes it possible to easily attach the water detection device to an object, and also to obtain a configuration in which the wiring pattern is protected by the cover layer when attached to the object.

[0022] In the fourth configuration, the mounting portion has a three-dimensional shape that exposes the other surface of the substrate and holds the substrate so that the other surface conforms to the surface of the object, allowing it to be attached to the object (seventh configuration).

[0023] This makes it possible to obtain a configuration in which the substrate can be positioned on an object while protecting one surface of the substrate on which the wiring pattern is formed.

[0024] In the first configuration, the substrate has a three-dimensional shape. The surface of the substrate opposite to the one surface has a shape that follows the surface shape of the object (eighth configuration).

[0025] This allows, for example, the substrate to be brought into contact with the surface of the object even if the surface is not flat.

[0026] In the first configuration, the water-soluble resin portion is made of a composite resin containing an acrylic resin and a polyalkylene glycol (ninth configuration).

[0027] This makes it possible to obtain a water-soluble resin portion that maintains its shape unless it comes into contact with water and that dissolves easily when it comes into contact with water.

[0028] In the ninth configuration, the acrylic resin is a polymer of a water-soluble monofunctional ethylenically unsaturated monomer (tenth configuration).

[0029] This makes it possible to obtain a water-soluble resin portion that dissolves in a short time when it comes into contact with water.

[0030] In any one of the first to tenth configurations, the water detection device further includes a power supply unit electrically connected to the terminal and supplying power to the wiring pattern, and a measurement unit that measures at least one of the current value flowing through the wiring pattern and the voltage value applied to the wiring pattern by the power supply unit (eleventh configuration).

[0031] This makes it possible to provide a water detection device that can detect water and easily identify the location of a water leak even after a period of time has passed.

[0032] In the eleventh configuration, the water detection device further includes a communication unit that transmits the measurement results of the measurement unit to the outside (twelfth configuration). This provides a configuration that allows the measurement results of the measurement unit to be transmitted to the outside.

[0033] A water detection system according to one embodiment of the present invention includes the water detection device of the twelfth configuration and a receiving device connected to the communication unit of the water detection device by wire or wirelessly to receive the measurement results from the communication unit. The receiving device has a determination unit that determines whether the water detection device has detected water based on the measurement results received from the communication unit (thirteenth configuration).

[0034] This makes it possible to provide a water detection system that can detect water based on the measurement results of the measuring unit and can easily identify the location of a water leak even after a period of time has passed.

[0035] A resin composition for a water detection device according to one embodiment of the present invention is a resin composition for a water detection device used to form the water-soluble resin part in the water detection device. This resin composition for a water detection device contains a water-soluble monofunctional ethylenically unsaturated monomer, a polyalkylene glycol, and a polymerization initiator (fourteenth feature).

[0036] This makes it possible to obtain a water-soluble resin portion that maintains its shape unless it comes into contact with water and that dissolves easily when it comes into contact with water.

[0037] In a method for manufacturing a water detection device according to one embodiment of the present invention, the substrate is formed by a three-dimensional fabrication method using a water-soluble resin composition (first method).

[0038] This allows the substrate including the water-soluble resin portion to be formed using, for example, a 3D printer, etc. Therefore, it is possible to easily manufacture a water detection device that can identify the location of a water leak even after the passage of time.

[0039] In the first method, the three-dimensional fabrication method is inkjet stereolithography (second method).

[0040] This makes it possible to form a substrate that partially includes a water-soluble resin portion using a 3D printer or the like.

[0041] In the second method, the substrate and the wiring pattern are formed using an inkjet type three-dimensional modeling device (third method).

[0042] This allows the substrate to be formed using a 3D printer or the like, and allows the wiring pattern to be formed simultaneously with the substrate.

[0043] According to one exemplary embodiment of the present invention, the substrate includes a plate-shaped water-soluble resin portion having one thickness-wise surface exposed to one side of the substrate and the other thickness-wise surface exposed to the other side of the substrate. In this water detection device, if water inside an object to which the water detection device is attached leaks to the surface, a portion of the substrate dissolves. This physically and electrically changes the state of a portion of the wiring pattern formed in the dissolved portion of the substrate. This provides a water detection device that can easily identify the location of a water leak even over time.

[0044] FIG. 1 is a cross-sectional view schematically showing the overall configuration of a water detection device according to Embodiment 1. FIG. 2 is an exploded perspective view schematically showing an example of a water detection device. FIG. 3 is a perspective view schematically showing a substrate in which a water-soluble resin portion has dissolved. FIG. 4 is a diagram schematically showing a method for fabricating a substrate. FIG. 5 is a cross-sectional view schematically showing the overall configuration of a water detection device according to Modification 1 of Embodiment 1. FIG. 6 is a perspective view schematically showing the overall configuration of a water detection device according to Modification 2 of Embodiment 1. FIG. 7 is a diagram schematically showing the overall configuration of a water detection system according to Embodiment 2. FIG. 8 is a cross-sectional view schematically showing the overall configuration of a water detection device according to Embodiment 3. FIG. 9 is a cross-sectional view schematically showing the overall configuration of a water detection device according to Embodiment 4. FIG. 10 is a cross-sectional view schematically showing the overall configuration of a water detection device according to another embodiment.

[0045] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In the drawings, the same or corresponding parts are designated by the same reference numerals and description thereof will not be repeated.

[0046] In each drawing used in this specification, the arrangement of each component is shown schematically to explain the interrelationship between each component, and the actual dimensional ratios, etc. may differ.

[0047] (Embodiment 1) (Water Detection Device) A water detection device 1 according to embodiment 1 will be described with reference to Figures 1 to 3. The water detection device 1 is a device that detects water. As shown in Figure 1, in this embodiment, the water detection device 1 is in the form of a sheet. The water detection device 1 is installed on the surface of an object M. The water detection device 1 detects water present on the surface of the object M on which it is installed.

[0048] The object M is, for example, an object or structure inside which water exists. The object M is, for example, a pipe. If the object M is a pipe, the water detection device 1 can be installed, for example, at a joint of the pipe. In this case, the water detection device 1 detects water when there is a leak from the joint. The water detection device 1 can also be installed, for example, below the joint on the pipe. In this case, the water detection device 1 detects water when water leaking from the joint flows downward along the surface of the pipe and reaches the water detection device 1.

[0049] The water detection device 1 may not only detect abnormal water such as water leakage, but also normal water.

[0050] 1 and 2, the water detection device 1 has a substrate 2, a wiring pattern 3, terminals 4, a mounting portion 5, a cover layer 6, a power supply portion 7, and a measurement portion 8. Fig. 1 is a cross-sectional view that schematically shows the overall configuration of the water detection device 1. Fig. 2 is an exploded perspective view that schematically shows an example of the water detection device 1.

[0051] In this embodiment, the substrate 2 is a plate-shaped circuit board. A wiring pattern 3 is formed on one surface of the substrate 2 in the thickness direction.

[0052] The substrate 2 has a main body portion 21 and a water-soluble resin portion 22. The substrate 2 is in the form of a plate in which the main body portion 21 and the water-soluble resin portion 22 are integrally formed. The main body portion 21 and the water-soluble resin portion 22 are each continuously formed along the thickness direction. That is, one surface in the thickness direction of the main body portion 21 and one surface in the thickness direction of the water-soluble resin portion 22 are exposed to one side in the thickness direction of the substrate 2. The other surface in the thickness direction of the main body portion 21 and the other surface in the thickness direction of the water-soluble resin portion 22 are exposed to the other side in the thickness direction of the substrate 2. Note that the arrangement of the main body portion 21 and the water-soluble resin portion 22 in Figures 1 and 2 is an example.

[0053] The substrate 2 is formed by inkjet stereolithography (hereinafter referred to as inkjet stereolithography), as described below. Inkjet stereolithography is a modeling method realized by a 3D printer that can freely create three-dimensional objects based on CAD (Computer Aided Design) data. The main body 21 is a so-called model material in inkjet stereolithography, and the water-soluble resin portion 22 is a so-called water-soluble support material in inkjet stereolithography.

[0054] The main body 21 is made of a resin that does not dissolve when it comes into contact with water. The water-soluble resin portion 22 is made of a resin that dissolves when it comes into contact with water. Therefore, as shown in Figure 3, when water comes into contact with the portion of the substrate 2 where the water-soluble resin portion 22 is located, a portion of the substrate 2 is damaged. Figure 3 is a perspective view that schematically shows the substrate 2 in a state where the water-soluble resin portion 22 has dissolved. Figure 3 shows the case where water comes into contact with the water-soluble resin portion 22 located on the left side of the figure.

[0055] In this embodiment, the main body 21 is made of a resin that is used to make a general circuit board. However, the main body may be made of a material other than resin as long as it is made of a material that is used to make a general circuit board.

[0056] The water-soluble resin portion 22 is composed of, for example, a composite resin containing an acrylic resin and a polyalkylene glycol. The acrylic resin is, for example, a polymer of a water-soluble monofunctional ethylenically unsaturated monomer. This allows for the formation of a water-soluble resin portion 22 that maintains its shape unless it comes into contact with water and that dissolves easily when it comes into contact with water. Details of the composition contained in the water-soluble resin portion 22 will be described later.

[0057] 1 and 2, the wiring pattern 3 is printed on one surface in the thickness direction of the substrate 2. Power is supplied to the wiring pattern 3 from a power supply unit 7 electrically connected to the terminals 4.

[0058] The wiring pattern 3 has a first wiring pattern 31 formed on the water-soluble resin portion 22 of the substrate 2, and a second wiring pattern 32 formed on the main body portion 21 of the substrate 2. In this embodiment, the first wiring pattern 31 and the second wiring pattern 32 are electrically connected when the portion of the water-soluble resin portion 22 where the first wiring pattern 31 is formed is not dissolved. Note that the configuration of the wiring pattern 3 in Figures 1 and 2 is an example.

[0059] 3, the first wiring pattern 31 breaks when the portion of the water-soluble resin part 22 where the first wiring pattern 31 is formed dissolves. Therefore, when water penetrates into the portion of the water-soluble resin part 22, the value of the current flowing through the wiring pattern 3 changes.

[0060] In this way, the first wiring pattern 31 and the second wiring pattern 32 are configured to be disconnected when the portion of the water-soluble resin part 22 where the first wiring pattern 31 is formed dissolves.

[0061] 1 and 2, the terminals 4 are electrically connected to the wiring patterns 3. The terminals 4 are electrically connected to a power supply unit 7.

[0062] The mounting unit 5 mounts the substrate 2 to the object M so that the other surface of the substrate 2 is aligned with the surface of the object M. The substrate 2 has a wiring pattern 3 formed on one surface thereof. Therefore, the mounting unit 5 mounts the substrate 2 to the surface of the object M in an orientation such that the surface in the thickness direction on which the wiring pattern 3 is formed is positioned outward.

[0063] In this embodiment, the attachment portion 5 is an adhesive layer 51 made of, for example, an adhesive. The adhesive layer 51 is laminated on part of the other surface in the thickness direction of the substrate 2. This allows the water detection device 1 to be attached to the object M. Therefore, the water detection device 1 can be easily attached to the object M.

[0064] The adhesive layer 51 has the same shape as the main body 21 when viewed in the thickness direction of the substrate 2, for example. That is, the adhesive layer 51 exposes the other surface in the thickness direction of the water-soluble resin part 22. Therefore, when water inside the object M leaks out into the part covered by the water-soluble resin part 22, the water-soluble resin part 22 dissolves.

[0065] The adhesive layer 51 also exposes the side surface of the water-soluble resin portion 22 located on the outer periphery of the substrate 2. Therefore, when water inside the object M flows over the surface of the object M and reaches the side surface of the water-soluble resin portion 22, the water-soluble resin portion 22 dissolves. The adhesive layer may be laminated on a portion of the main body portion or on a portion of the water-soluble resin portion.

[0066] The cover layer 6 covers one surface of the substrate 2. In other words, when the substrate 2 is attached to the surface of the object M, the cover layer 6 covers the wiring pattern 3 formed on one surface of the substrate 2. This makes it possible to obtain a configuration in which the wiring pattern 3 is protected when the water detection device 1 is attached to the object M.

[0067] The power supply unit 7 is electrically connected to the terminals 4. The power supply unit 7 supplies power to the wiring pattern 3. The power supply unit 7 is, for example, a battery. Although the water detection device 1 has the power supply unit 7 in this embodiment, the water detection device does not have to have a power supply unit. For example, power may be supplied to the terminals of the water detection device from an external power source.

[0068] The measuring unit 8 measures at least one of the value of the current flowing through the wiring pattern 3 and the value of the voltage applied to the wiring pattern 3 by the power supply unit 7. As described above, the wiring pattern 3 is configured so that the current value changes when water comes into contact with the substrate 2. Therefore, when water comes into contact with the water-soluble resin portion 22, the current value or voltage value measured by the measuring unit 8 changes. This allows the water detection device 1 to detect water that has leaked from the inside of the object M to the outside.

[0069] The measuring unit 8 may be configured to measure the current value or voltage value at a predetermined timing, or may be configured to measure the current value or voltage value when a measurement command is input. The measuring unit 8 may also have a storage unit that stores the measurement results.

[0070] In this embodiment, the water detection device 1 has a measurement unit 8, but the water detection device does not have to have a measurement unit. For example, the measurement unit may be an external measurement unit electrically connected to the wiring pattern of the water detection device.

[0071] The water detection device 1 according to this embodiment, having the above-described configuration, is attached to an object M and detects water. The water detection device 1 has a substrate 2, a wiring pattern 3 formed on either one surface or the other surface in the thickness direction of the substrate 2, and a terminal 4 electrically connected to the wiring pattern 3 and to which a power source is connected. The substrate 2 includes a plate-shaped water-soluble resin part 22 having one surface in the thickness direction exposed to one side of the substrate in the thickness direction and the other surface in the thickness direction exposed to the other side of the substrate in the thickness direction. At least a portion of the wiring pattern 3 is formed on the water-soluble resin part 22.

[0072] In the above-described configuration, the water-soluble resin portion 22 dissolves when it comes into contact with water. Therefore, when water inside the object M to which the water detection device 1 is attached leaks out to the surface, part of the substrate 2 dissolves. This physically changes the state of part of the wiring pattern 3 that was formed in the dissolved part of the substrate 2. As a result, by supplying power to the wiring pattern 3 from the terminal 4, the value of the current flowing through the wiring pattern 3 can be changed when water comes into contact with the substrate 2. Therefore, water can be detected based on the change in the current value.

[0073] Furthermore, with the above-described configuration, the portion of the substrate 2 that comes into contact with water dissolves. This makes it possible to identify the location of a water leak even after the passage of time. Therefore, it is possible to provide a water detection device 1 that can easily identify the location of a water leak even after the passage of time.

[0074] In this embodiment, the wiring pattern 3 has a first wiring pattern 31, at least a portion of which is formed on the water-soluble resin portion 22 of the substrate 2, and a second wiring pattern 32, which is formed on the main body portion 21 of the substrate 2 and is electrically connected to the first wiring pattern 31. The first wiring pattern 31 is disconnected when the portion of the water-soluble resin portion 22 on which the first wiring pattern 31 is formed dissolves.

[0075] This makes it possible to realize a configuration in which the value of the current flowing through the wiring pattern 3 decreases when the water-soluble resin portion 22 dissolves. Therefore, it is possible to provide a water detection device 1 that can detect water based on changes in the current value and can easily identify the location of a water leak even after a period of time has passed.

[0076] It should be noted that the water-soluble resin portion 22 may swell rather than dissolve in the area where it comes into contact with water. In this case, the water-soluble resin portion 22 may no longer be able to maintain its shape, and part or all of the water-soluble resin portion 22 may detach from the substrate 2. Furthermore, the state of part of the wiring pattern 3 formed in the area of ​​the substrate 2 where the water-soluble resin portion 22 has swelled may physically change. Therefore, even when the water-soluble resin portion 22 has swelled, water can be detected in the same way as when the water-soluble resin portion 22 has dissolved.

[0077] (Resin composition for water-soluble resin portion) Next, the resin constituting the water-soluble resin portion 22 will be described. The water-soluble resin portion 22 is composed of a resin obtained by irradiating an energy ray-curable resin composition X with a light source and curing it. The energy ray-curable resin composition X has the same components as the resin composition used to shape a water-soluble support material in inkjet stereolithography. The light source is an ultraviolet lamp. Hereinafter, the energy ray-curable resin composition X will be referred to as resin composition X.

[0078] Specifically, resin composition X contains an acrylic resin and a polyalkylene glycol. That is, the water-soluble resin portion 22 is a cured product of a composite resin containing an acrylic resin and a polyalkylene glycol. The acrylic resin contains a polymer of a water-soluble monofunctional ethylenically unsaturated monomer, and is preferably a polymer of a water-soluble monofunctional ethylenically unsaturated monomer. That is, the resin composition used to form the water-soluble resin portion 22 contains a water-soluble monofunctional ethylenically unsaturated monomer, a polyalkylene glycol, and a polymerization initiator.

[0079] More specifically, resin composition X contains, relative to 100 parts by weight of the entire resin composition, 19 to 80 parts by weight of a water-soluble monofunctional ethylenically unsaturated monomer, 15 to 75 parts by weight of a polyalkylene glycol, 35 parts by weight or less of a water-soluble organic solvent, and 5 to 20 parts by weight of a photopolymerization initiator.

[0080] <Water-soluble monofunctional ethylenically unsaturated monomer> The water-soluble monofunctional ethylenically unsaturated monomer is a component that polymerizes upon light irradiation to cure the resin composition X. In addition, the water-soluble monofunctional ethylenically unsaturated monomer is a component that quickly dissolves in water the water-soluble resin part 22 obtained by photocuring the resin composition X.

[0081] The above component is a water-soluble polymerizable monomer having one ethylenic double bond in the molecule and capable of being cured by energy rays. The above component is preferably a compound having one acrylic group in the molecule, such as a hydroxyl group-containing (meth)acrylate having 5 to 15 carbon atoms [e.g., hydroxyethyl (meth)acrylate, hydroxypropyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, etc.], a hydroxyl group-containing (meth)acrylate having Mn of 200 to 1,000 [polyethylene glycol mono(meth)acrylate, monoalkoxy (carbon number 1 to 4) polyethylene glycol mono(meth)acrylate, polypropylene glycol mono(meth)acrylate, monoalkoxy (carbon number 1 to 4) polypropylene glycol mono(meth)acrylate, etc.], or a hydroxyl group-containing (meth)acrylate having Mn of 200 to 1,000 [e.g., polyethylene glycol mono(meth)acrylate, monoalkoxy (carbon number 1 to 4) polyethylene glycol mono(meth)acrylate, polypropylene glycol mono(meth)acrylate, monoalkoxy (carbon number 1 to 4) polypropylene glycol mono(meth)acrylate]. acrylate, mono(meth)acrylate of PEG-PPG block polymer, etc.), (meth)acrylamide derivatives having 3 to 15 carbon atoms [(meth)acrylamide, N-methyl(meth)acrylamide, N-ethyl(meth)acrylamide, N-propyl(meth)acrylamide, N-butyl(meth)acrylamide, N,N'-dimethyl(meth)acrylamide, N,N'-diethyl(meth)acrylamide, N-hydroxyethyl(meth)acrylamide, N-hydroxypropyl(meth)acrylamide, N-hydroxybutyl(meth)acrylamide, etc.], (meth)acryloylmorpholine, etc. These may be used alone or in combination of two or more. When two or more of the above components are contained, the content is defined as the total content of each component.

[0082] Among these, N,N'-dimethyl(meth)acrylamide, N-hydroxyethyl(meth)acrylamide, (meth)acryloylmorpholine, etc. are preferred from the viewpoint of improving the curability of resin composition X. Furthermore, N-hydroxyethyl(meth)acrylamide and (meth)acryloylmorpholine are more preferred from the viewpoint of low skin irritation to the human body.

[0083] The content of the above components is 19 to 80 parts by weight, preferably 20 to 50 parts by weight, relative to 100 parts by weight of the total resin composition X. When the content of the above components is within the upper and lower limit ranges, shape retention of the water-soluble resin part 22 obtained by photocuring the resin composition X can be ensured, and sensitivity to water detected by the water-soluble resin part 22 can be ensured. The content of the above components can be adjusted as appropriate depending on the amount of water to be detected, the location of the leak, the installation environment, etc.

[0084] Furthermore, in addition to the water-soluble monofunctional ethylenically unsaturated monomer, a monofunctional ethylenically unsaturated monomer, which is a compound having one acrylic group in one molecule, may be contained within a range that does not impair the sensitivity of the water-soluble resin portion 22. The amount of the monofunctional ethylenically unsaturated monomer is 10 parts by weight or less, preferably 5 parts by weight or less, and more preferably 3 parts by weight or less, relative to 100 parts by weight of the entire resin composition X. By containing the monofunctional ethylenically unsaturated monomer, the mechanical strength of the water-soluble resin portion 22 may be improved.

[0085] <Polyalkylene glycol> Polyalkylene glycol increases the solubility in water of the water-soluble resin part 22 obtained by photocuring the resin composition X. Polyalkylene glycol is a water-soluble compound that imparts appropriate hydrophilicity to the water-soluble resin part 22, and by adding this, it is possible to obtain a water-soluble resin part 22 that is excellent in shape retention and sensitivity.

[0086] The polyalkylene glycol has at least one type of oxyalkylene group added to an active hydrogen compound. Examples of the oxyalkylene group include an oxyethylene group, an oxypropylene group, and an oxybutylene group. The polyalkylene glycol may contain an oxyalkylene group, and may be, for example, a polybutylene glycol alone having only an oxybutylene group (oxytetramethylene group), or a polybutylene polyoxyalkylene glycol (e.g., polybutylene polyethylene glycol) having both an oxybutylene group and another oxyalkylene group. Specific examples include polyethylene glycol, polypropylene glycol, polybutylene glycol, and polybutylene polyethylene glycol. These may be used alone or in combination of two or more. Examples of the active hydrogen compound include monohydric to tetrahydric alcohols and amine compounds. Among these, dihydric alcohols are preferred. When two or more of the above components are contained, the content is determined as the sum of the contents of the individual components.

[0087] The number-average molecular weight Mn of the above component is preferably 100 to 5,000. When the Mn of the above component is within the above range, the component is compatible with the water-soluble monofunctional ethylenically unsaturated monomer before photocuring, but is incompatible with the water-soluble monofunctional ethylenically unsaturated monomer after photocuring. As a result, the shape retention of the detection unit obtained by photocuring the resin composition can be improved, and the solubility in water can also be increased. The Mn of the above component is more preferably 200 to 3,000, and even more preferably 400 to 2,000.

[0088] The content of the above components is 15 to 75 parts by weight, and preferably 20 to 49 parts by weight, relative to 100 parts by weight of the total resin composition X. When the content of the above components is within the upper and lower limit ranges, the water-soluble resin part 22 obtained by photocuring the resin composition X has excellent shape retention and solubility in water, and can also suppress leaching of the above components from the water-soluble resin part 22. The content of the above components can be adjusted as appropriate depending on the amount of water to be detected, the location of the leak, the installation environment, etc.

[0089] <Water-soluble organic solvent> The water-soluble organic solvent is a component that improves the solubility in water of the water-soluble resin part 22 obtained by photo-curing the resin composition X. The water-soluble organic solvent is also a component that adjusts the viscosity of the resin composition X to be low.

[0090] The above-mentioned component can be anything other than the above-mentioned polyalkylene glycol, for example, glycol ether solvent, glycol ether acetate solvent and other solvents.Specific compounds can be, for example, ethylene glycol monoacetate, propylene glycol monoacetate, diethylene glycol monoacetate, dipropylene glycol monoacetate, triethylene glycol monoacetate, tripropylene glycol monoacetate, tetraethylene glycol monoacetate, tetrapropylene glycol monoacetate, ethylene glycol monomethyl ether, propylene glycol monomethyl ether, diethylene glycol monomethyl ether, dipropylene glycol monomethyl ether, triethylene glycol monomethyl ether, tripropylene glycol monomethyl ether, tetraethylene glycol monomethyl ether, tetrapropylene glycol monomethyl ether, ethylene glycol monoethyl ether, propylene glycol monoethyl ether, diethylene glycol monoethyl ether, dipropylene glycol monoethyl ether, triethylene glycol monoethyl ether, tripropylene glycol monoethyl ether. , tetraethylene glycol monoethyl ether, tetrapropylene glycol monoethyl ether, ethylene glycol monopropyl ether, propylene glycol monopropyl ether, diethylene glycol monopropyl ether, dipropylene glycol monopropyl ether, triethylene glycol monopropyl ether, tripropylene glycol monopropyl ether, tetraethylene glycol monopropyl ether, tetrapropylene glycol monopropyl ether, ethylene glycol monobutyl ether, propylene glycol monobutyl ether, diethylene glycol monobutyl ether, dipropylene glycol monobutyl ether, triethylene glycol monobutyl ether, tripropylene glycol monobutyl ether, tetraethylene glycol monobutyl ether, tetrapropylene glycol monobutyl ether, ethylene glycol diacetate, propylene glycol diacetate, diethylene glycol diacetate, dipropylene glycol diacetate,Triethylene glycol diacetate, tripropylene glycol diacetate, tetraethylene glycol diacetate, tetrapropylene glycol diacetate, ethylene glycol dimethyl ether, propylene glycol dimethyl ether, diethylene glycol dimethyl ether, dipropylene glycol dimethyl ether, triethylene glycol dimethyl ether, tripropylene glycol dimethyl ether, tetraethylene glycol dimethyl ether, tetrapropylene glycol dimethyl ether, ethylene glycol diethyl ether, propylene glycol diethyl ether, diethylene glycol diethyl ether, dipropylene glycol diethyl ether, triethylene glycol diethyl ether, tripropylene glycol diethyl ether, tetraethylene glycol diethyl ether, tetrapropylene glycol diethyl ether, ethylene glycol dipropyl ether, propylene glycol dipropyl ether, diethylene glycol dipropyl ether, dipropylene glycol dipropyl ether, triethylene glycol dipropyl Phenyl ether, tripropylene glycol dipropyl ether, tetraethylene glycol dipropyl ether, tetrapropylene glycol dipropyl ether, ethylene glycol dibutyl ether, propylene glycol dibutyl ether, diethylene glycol dibutyl ether, dipropylene glycol dibutyl ether, triethylene glycol dibutyl ether, tripropylene glycol dibutyl ether, tetraethylene glycol dibutyl ether, tetrapropylene glycol dibutyl ether, ethylene glycol monomethyl ether acetate, propylene glycol monomethyl ether acetate, diethylene glycol monomethyl ether acetate, dipropylene glycol monomethyl ether acetate, triethylene glycol monomethyl ether acetate, tripropylene glycol monomethyl ether acetate, tetraethylene glycol monomethyl ether acetate, tetrapropylene glycol monomethyl ether acetate, ethylene glycol monoethyl ether acetate, propylene glycol monoethyl ether acetate,Diethylene glycol monoethyl ether acetate, dipropylene glycol monoethyl ether acetate, triethylene glycol monoethyl ether acetate, tripropylene glycol monoethyl ether acetate, tetraethylene glycol monoethyl ether acetate, tetrapropylene glycol monoethyl ether acetate, ethylene glycol monopropyl ether acetate, propylene glycol monopropyl ether acetate, diethylene glycol monopropyl ether acetate, dipropylene glycol monopropyl ether acetate, triethylene glycol monopropyl ether acetate, tripropyl Examples of the ethylene glycol monopropyl ether acetate include ethylene glycol monopropyl ether acetate, tetraethylene glycol monopropyl ether acetate, tetrapropylene glycol monopropyl ether acetate, ethylene glycol monobutyl ether acetate, propylene glycol monobutyl ether acetate, diethylene glycol monobutyl ether acetate, dipropylene glycol monobutyl ether acetate, triethylene glycol monobutyl ether acetate, tripropylene glycol monobutyl ether acetate, tetraethylene glycol monobutyl ether acetate, and tetrapropylene glycol monobutyl ether acetate.

[0091] Other solvents include, for example, ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, dipropylene glycol, 1,2-propanediol, 1,3-propanediol, 1,2-butanediol, 1,3-butanediol, 1,4-butanediol, 2,3-butanediol, 2,2-dimethyl-1,3-propanediol, 2-methyl-1,3-propanediol, 1,2-pentanediol, 1,5-pentanediol, 2,4-pentanediol, 2,5-pentanediol, 2,6-pentanediol, 2,7-pentanediol, 2,8-pentanediol, 2,9-pentanediol, 3,4-pentanediol, 3,5-pentanediol, 3,6-pentanediol, 3,7-pentanediol, 3,8-pentanediol, 3,9 ... Examples of suitable solvents include alcoholic solvents such as pentanediol, 1,2-hexanediol, 3,5-dimethyl-3-hexyne-2,5-diol, 2,5-hexanediol, hexylene glycol, 1,6-hexanediol, 2-ethyl-1,3-hexanediol, 2,2,4-trimethyl-1,3-pentanediol, 2,5-dimethyl-2,5-hexanediol, 1,4-cyclohexanedimethanol, and 2,2-thiodiethanol, as well as 2-pyrrolidone and N-methyl-2-pyrrolidone. These may be used alone or in combination of two or more.

[0092] Among the above, triethylene glycol monomethyl ether or dipropylene glycol monomethyl ether acetate is more preferable from the viewpoint of improving the solubility in water of the water-soluble resin portion 22 and adjusting the viscosity of the resin composition X to a low level. When two or more of the above components are contained, the content is defined as the total content of each component.

[0093] The content of the above component is 35 parts by weight or less, and preferably 30 parts by weight, relative to 100 parts by weight of the total resin composition X. When the content of the above component is within the upper limit range, the solubility of the water-soluble resin portion 22 in water can be improved. From the viewpoint of adjusting the resin composition to a low viscosity, the content of the above component is preferably 5 parts by weight or more, and more preferably 10 parts by weight or more.

[0094] <Photopolymerization Initiator> The photopolymerization initiator is not particularly limited as long as it is a compound that promotes a radical reaction when irradiated with light having a wavelength in the ultraviolet, near-ultraviolet, or visible light region. Examples of the above components include benzoin compounds having 14 to 18 carbon atoms (e.g., benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin propyl ether, benzoin isobutyl ether, etc.), acetophenone compounds having 8 to 18 carbon atoms (e.g., acetophenone, 2,2-diethoxy-2-phenylacetophenone, 2,2-diethoxy-2-phenylacetophenone, 1,1-dichloroacetophenone, 2-hydroxy-2-methyl-phenylpropan-1-one, diethoxyacetophenone, 1-hydroxycyclohexyl phenyl ketone, 2-methyl-1-[4-(methylthio)phenyl]-2-morpholinopropan-1-one, etc.), and anthraquinone compounds having 14 to 19 carbon atoms (e.g., 2-ethylanthraquinone, 2-t-butylanthraquinone, 2-chloroanthraquinone, 2-amylanthraquinone, etc.). etc.), thioxanthone compounds having 13 to 17 carbon atoms [e.g., 2,4-diethylthioxanthone, 2-isopropylthioxanthone, 2-chlorothioxanthone, etc.], ketal compounds having 16 to 17 carbon atoms [e.g., acetophenone dimethyl ketal, benzyl dimethyl ketal, etc.], benzophenone compounds having 13 to 21 carbon atoms [e.g., benzophenone, 4-benzoyl-4'-methyldiphenyl sulfide, 4,4'-bismethylaminobenzophenone, etc.], acylphosphine oxide compounds having 22 to 28 carbon atoms [e.g., 2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide, bis-(2,6-dimethoxybenzoyl)-2,4,4-trimethylpentylphosphine oxide, bis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide], mixtures of these compounds, etc. These may be used alone or in combination of two or more. Among these, acylphosphine oxide compounds having 22 to 28 carbon atoms are preferred, from the viewpoint that the water-soluble resin portion 22 obtained by photocuring the resin composition X is less likely to yellow and has excellent light resistance.Specifically, 2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide or bis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide is preferred. Also, available acylphosphine oxide compounds include, for example, DAROCURE TPO manufactured by BASF. When two or more of the above components are contained, the content is defined as the total content of each component.

[0095] The content of the above component is 1 to 20 parts by weight relative to 100 parts by weight of the total resin composition X. When the content of the above component is within this range, the resin composition X can be sufficiently cured, and the shape retention of the water-soluble resin part 22 obtained by curing the resin composition X is good. The content of the above component is preferably 3 parts by weight or more, more preferably 5 parts by weight or more. Also, it is preferably 18 parts by weight or less, and more preferably 15 parts by weight or less.

[0096] <Other Components> Other additives may be added to the resin composition X as needed, as long as they do not impair the effects of the present invention. Examples of other additives include colorants, storage stabilizers, surface conditioners, UV absorbers, chain transfer agents, and fillers.

[0097] <Colorant> The resin composition X may contain a colorant. The colorant is a component that colors the resin composition X. By coloring the resin composition X, for example, it is possible to change the color of the portion of the water-soluble resin part 22 that is in contact with water. This makes it possible to visually recognize the portion that is in contact with water.

[0098] Examples of the above components include pigments and dyes. Either inorganic or organic pigments, or both, can be used as pigments. Examples of pigments that can be used include cyan, magenta, yellow, black, and white pigments. In some cases, special color pigments such as violet, blue, green, orange, and red can also be used. Another example is fluorescent pigments, such as pigments obtained by dyeing one or more synthetic resins, such as polyamide resins, formaldehyde polycondensates, ketone resins, and vinyl copolymers, with oil-based and basic dyes as colorants. Examples of dyes that can be used include dyes that emit fluorescence upon exposure to energy rays (fluorescent dyes). Specific examples include perylene-based compounds, perylimide-based compounds, violanthrone-based compounds, and coumarin-based compounds. The content of the above components is preferably 0.1 to 20 parts by weight, and more preferably 0.3 to 15 parts by weight, per 100 parts by weight of the total resin composition.

[0099] <Storage stabilizer> The resin composition X preferably contains a storage stabilizer. The storage stabilizer can increase the storage stability of the resin composition X and may also be able to suppress deterioration of the water-soluble resin part 22 due to light such as sunlight.

[0100] Examples of the above-mentioned components include hindered amine compounds (HALS), phenolic antioxidants, and phosphorus-based antioxidants. Specific examples include hydroquinone, methoquinone, benzoquinone, p-methoxyphenol, hydroquinone monomethyl ether, hydroquinone monobutyl ether, TEMPO, 4-hydroxy-TEMPO, TEMPOL, Al cupferron, IRGASTAB UV-10, IRGASTAB UV-22, FIRSTCURE ST-1 (manufactured by ALBEMARLE), t-butylcatechol, pyrogallol, and TINUVIN 111 FDL, TINUVIN 144, TINUVIN 292, TINUVIN XP40, TINUVIN XP60, and TINUVIN 400 (manufactured by BASF). These may be used alone or in combination of two or more. When two or more of the above components are contained, the content is determined as the total content of each component. The content of the above component is preferably 0.05 to 3.0 parts by weight per 100 parts by weight of the total resin composition X.

[0101] <Surface Conditioner> A surface conditioner is preferably contained in order to adjust the surface tension of the resin composition X to an appropriate range. Examples of the above component include silicone-based compounds. Examples of the silicone-based compound include silicone-based compounds having a polydimethylsiloxane structure. Specific examples include polyether-modified polydimethylsiloxane, polyester-modified polydimethylsiloxane, and polyaralkyl-modified polydimethylsiloxane. These include, by trade name, BYK-300, BYK-302, BYK-306, BYK-307, BYK-310, BYK-315, BYK-320, BYK-322, BYK-323, BYK-325, BYK-330, BYK-331, BYK-333, BYK-337, BYK-344, BYK-370, BYK-375, BYK-377, BYK-UV3500, BYK-UV3510, BYK-UV3570 (all manufactured by BYK-Chemie), TEGO-Rad21 00, TEGO-Rad 2200N, TEGO-Rad 2250, TEGO-Rad 2300, TEGO-Rad 2500, TEGO-Rad 2600, TEGO-Rad 2700 (all manufactured by Degussa), Granol 100, Granol 115, Granol 400, Granol 410, Granol 435, Granol 440, Granol 450, B-1484, Polyflow ATF-2, KL-600, UCR-L72, UCR-L93 (manufactured by Kyoeisha Chemical Co., Ltd.), etc. may also be used. These may be used alone or in combination of two or more. When two or more of the above components are contained, the content is defined as the total content of each component. The content of the above component is preferably 0.005 to 3.0 parts by weight per 100 parts by weight of the total resin composition X.

[0102] <Production Method> There are no particular limitations on the production method of the resin composition X according to this embodiment. For example, the resin composition X can be produced by uniformly mixing the above components and, if necessary, other additives using a mixer or stirrer.

[0103] <Physical Properties, etc.> From the viewpoint of improving the ejection properties from an inkjet head, the resin composition X according to this embodiment produced in this manner preferably has a viscosity of 70 mPa·s or less at 25° C. The viscosity of the resin composition X can be measured in accordance with JIS Z 8803 using an R100 type viscometer.

[0104] (Method of Manufacturing Substrate) Next, a method of manufacturing the substrate 2 of the water detection device 1 according to the first embodiment will be described with reference to FIG.

[0105] In this embodiment, the substrate 2 is produced by a three-dimensional modeling method using the resin composition Y used to form the main body portion 21 and the above-mentioned water-soluble resin composition X. In this embodiment, the three-dimensional modeling method is inkjet stereolithography. The inkjet stereolithography is a known inkjet method used in 3D printers. Therefore, a detailed description of the inkjet stereolithography method will be omitted.

[0106] FIG. 4 is a diagram schematically illustrating a method for fabricating the substrate 2 according to this embodiment. As shown in FIG. 4, the substrate 2 is fabricated by a three-dimensional modeling apparatus T. The three-dimensional modeling apparatus T has a modeling table T1 and an inkjet head module T2. The inkjet head module T2 has a first inkjet head T3, a second inkjet head T4, and a light source T5. The first inkjet head T3 is filled with a resin composition Y used to form the main body portion 21 of the substrate 2. The second inkjet head T4 is filled with the above-mentioned resin composition X used to form the water-soluble resin portion 22.

[0107] The three-dimensional modeling device T scans the first inkjet head T3 and the second inkjet head T4 relatively to the modeling table T1, and ejects the resin composition Y for the main body portion 21 from the first inkjet head T3 and ejects the resin composition X for the water-soluble resin portion 22 from the second inkjet head T4. As a result, resin composition layers made of the resin composition Y for the main body portion 21 and the resin composition X for the water-soluble resin portion 22 are formed on the modeling table T1. Then, by irradiating these resin composition layers with light using the light source T5, a cured layer made of the resin composition Y for the main body portion 21 and the resin composition X for the water-soluble resin portion 22 is formed on the modeling table T1.

[0108] By repeating the above steps, the substrate 2 made of the resin composition Y for the main body portion 21 and the resin composition X for the water-soluble resin portion 22 is produced.

[0109] That is, in the manufacturing method of the water detection device 1 according to this embodiment, the substrate 2 is formed by a three-dimensional modeling method using the water-soluble resin composition X. The three-dimensional modeling method is inkjet stereolithography. This makes it possible to form the substrate 2 including the water-soluble resin portion 22 using, for example, a 3D printer. Therefore, it is possible to easily manufacture a water detection device 1 that can identify the location of a water leak even after the passage of time.

[0110] The three-dimensional modeling apparatus T may be configured to fabricate the substrate 2 and form the wiring pattern 3 on the substrate 2. For example, the three-dimensional modeling apparatus T may have a third inkjet head filled with conductive ink for forming the wiring pattern 3. This allows the three-dimensional modeling apparatus T to form the wiring pattern 3 on the substrate 2 after fabricating the substrate 2 by ejecting conductive ink from the third inkjet head. In other words, the three-dimensional modeling apparatus T can form the substrate 2 and the wiring pattern 3. Therefore, the water detection device 1 can be easily manufactured. The conductive ink may be any ink as long as the formed wiring pattern is conductive, and may include, for example, a conductive polymer, a metal, a metal oxide, etc.

[0111] (First Modification of First Embodiment) Figure 5 is a cross-sectional view schematically showing the overall configuration of a water detection device 101 according to a first modification of the first embodiment. In the first embodiment, the substrate 2 has a main body portion 21 and a water-soluble resin portion 22. The wiring pattern 3 has a first wiring pattern 31 formed on the water-soluble resin portion 22 and a second wiring pattern 32 formed on the main body portion 21. However, as shown in Figure 5, the wiring pattern 103 may be formed only on the water-soluble resin portion 122. In this case, the substrate 102 does not need to have a main body portion, as shown in Figure 5.

[0112] Even with this configuration, the wiring pattern 103 will break if the portion of the water-soluble resin part 122 on which the wiring pattern 103 is formed dissolves. Therefore, this modified example also realizes a configuration in which the current value changes when the water-soluble resin part 122 dissolves. Therefore, it is possible to provide a water detection device that can detect water based on the change in the current value and can easily identify the location of a water leak even after time has passed.

[0113] 6, the water detection device 201 may have a communication unit 209 on the substrate 2. The communication unit 209 is configured to be able to transmit the measurement results of the measurement unit 8 to the outside. This provides a configuration that allows the measurement results of the measurement unit 8 to be transmitted to the outside.

[0114] Second Embodiment A water detection system 300 having a water detection device will be described with reference to Fig. 7. Fig. 7 is a diagram showing a schematic configuration of the water detection system 300. As shown in Fig. 7, the water detection system 300 has a plurality of water detection devices 301 and a receiving device 310.

[0115] The water detection device 301 has a substrate 2, wiring pattern 3, terminals 4, mounting section 5, cover layer 6, power supply section 7, measurement section 8, and a communication section 209, each of which has the same configuration as in embodiment 1. The configuration of the water detection device 301 is the same as the configuration of the water detection devices 1 and 201 in embodiment 1 and embodiment 1, respectively, and therefore a description thereof will be omitted.

[0116] The receiving device 310 is connected by wire or wirelessly to the communication units 209 of each of the multiple water detection devices 301. The receiving device 310 is configured to be able to receive signals from the communication units 209. In other words, the receiving device 310 receives the measurement results of the measurement unit 8.

[0117] The receiving device 310 has a determination unit 311. The determination unit 311 determines whether or not each water detection device 301 has detected water based on the measurement results of the measurement unit 8 received from the communication unit 209. In this embodiment, when a water detection device 301 detects water, the current value measured by the measurement unit 8 changes. Therefore, when the current value changes, the determination unit 311 determines that the water detection device 301 has detected water.

[0118] This makes it possible to provide a water detection system 300 that detects water based on the measurement results of the measuring unit 8 and can easily identify the location of a water leak even after some time has passed.

[0119] (Embodiment 3) A water detection device 401 according to embodiment 3 will be described with reference to Figure 8. In this embodiment, the water detection device 401 differs from the wiring pattern 3 of embodiment 1 in the configuration of the wiring pattern 403. Specifically, in this embodiment, when the water-soluble resin portion 22 dissolves, a current flows through the wiring pattern 403. Below, the same components as those in embodiment 1 are given the same reference numerals, and their description will be omitted, and only components different from those in embodiment 1 will be described.

[0120] Fig. 8 is a cross-sectional view showing a schematic configuration of a water detection device 401. As shown in Fig. 8, the water detection device 401 has a substrate 2, a wiring pattern 403, and terminals 4. The terminals are not shown.

[0121] In this embodiment, the wiring pattern 403 has a first wiring pattern 431 formed on the water-soluble resin portion 22 of the substrate 2, and a second wiring pattern 432 formed on the main body portion 21 of the substrate 2. The second wiring pattern 432 is printed on one surface of the substrate 2 in the thickness direction.

[0122] The first wiring pattern 431 is formed of a conductive leaf spring-like member. A central portion 431a of the first wiring pattern 431 is in contact with the water-soluble resin portion 22. Both end portions 431b, 431c of the first wiring pattern 431 are separated from the water-soluble resin portion 22. When the water-soluble resin portion 22 is not dissolved, both end portions 431b, 431c of the first wiring pattern 431 are not in contact with the second wiring pattern 432. Therefore, when power is supplied to the wiring pattern 403, no current flows through the wiring pattern 403.

[0123] Both end portions 431b, 431c of the first wiring pattern 431 overlap with ends of the second wiring pattern 432 when viewed in the thickness direction of the substrate 2. The distance in the thickness direction between the central portion 431a of the first wiring pattern 431 and both end portions 431b, 431c is equal to or smaller than the thickness of the water-soluble resin portion 22.

[0124] Therefore, when the water-soluble resin portion 22 dissolves, both end portions 431b, 431c of the first wiring pattern 431 come into contact with the end portions of the second wiring pattern 432. This electrically connects the first wiring pattern 431 and the second wiring pattern 432. Therefore, when power is supplied to the wiring pattern 403, a current flows through the wiring pattern 403.

[0125] As described above, the wiring pattern 403 of the water detection device 401 according to this embodiment has a first wiring pattern 431, at least a portion of which is formed on the water-soluble resin portion 22 of the substrate 2, and a second wiring pattern 432, which is formed on the main body portion 21 of the substrate 2. Both end portions 431b, 431c of the first wiring pattern 431 are positioned so as to overlap with the ends of the second wiring pattern 432 when viewed in the thickness direction. The water-soluble resin portion 22 dissolves and makes electrical contact with the ends of the second wiring pattern 432, thereby electrically connecting to the second wiring pattern 432.

[0126] The configuration of this embodiment also makes it possible to realize a configuration in which the current value changes when the water-soluble resin part 22 dissolves. Therefore, it is possible to provide a water detection device that can detect water based on the change in the current value and can easily identify the location of a water leak even after a period of time has passed.

[0127] (Fourth embodiment) A water detection device 501 according to a fourth embodiment will be described with reference to Fig. 9. In this embodiment, the water detection device 501 has a mounting portion 505 with a different configuration from the mounting portion 5 of the first embodiment. Below, the same components as those in the first embodiment are given the same reference numerals, and their description will be omitted, and only the components different from those in the first embodiment will be described.

[0128] Fig. 9 is a cross-sectional view showing a schematic configuration of a water detection device 501. As shown in Fig. 9, the water detection device 501 has a substrate 502, a wiring pattern 503, terminals 4, and a mounting portion 505. The terminals are not shown.

[0129] In this embodiment, the substrate 502 is made of a water-soluble resin part 522. The wiring pattern 503 is formed on one surface of the water-soluble resin part 522.

[0130] The attachment portion 505 has a three-dimensional shape. For example, the attachment portion 505 has a shape that fits onto the outer surface of the object M. For example, if the object M is cylindrical, the attachment portion 505 has a cylindrical shape.

[0131] The mounting portion 505 exposes the other surface of the substrate 502 and holds the substrate 502 so that the other surface is aligned with the surface of the object M. This makes it possible to obtain a configuration in which the substrate 502 can be positioned on the object M while protecting one surface of the substrate 502 on which the wiring pattern 503 is formed. The mounting portion may have a receiving groove for holding the substrate.

[0132] This makes it possible to obtain a configuration in which the mounting portion 505 protects one surface of the substrate 502 on which the wiring pattern 503 is formed, while allowing the substrate 502 to be positioned on an object.

[0133] While the embodiments of the present invention have been described above, the above-described embodiments are merely examples for carrying out the present invention. Therefore, the present invention is not limited to the above-described embodiments, and can be practiced by appropriately modifying the above-described embodiments within the scope of the spirit thereof.

[0134] In the first embodiment, the water detection device 1, 101 has the mounting portion 5. However, the water detection device does not have to have a mounting portion. The water detection device may be attached to an object using a general mounting member.

[0135] In the first embodiment, the water detection device 1, 101 has an adhesive layer 51 as the attachment portion 5. However, the water detection device may have an attachment portion with another configuration that allows the water detection device to be attached to an object. For example, the water detection device may be attached to the object by a wire connected to a substrate.

[0136] In the first embodiment, the water detection device 1, 101 has a cover layer 6. However, the water detection device does not have to have a cover layer. The cover layer can protect the wiring pattern. Therefore, it is preferable that the water detection device has a cover layer.

[0137] In the first embodiment, the power supply unit 7 and the measurement unit 8 are disposed outside the substrate 2. However, the power supply unit and the measurement unit may be disposed on the substrate.

[0138] In the first embodiment, the substrate 2 is fabricated by inkjet stereolithography. However, the substrate may be fabricated by a three-dimensional fabrication method other than inkjet stereolithography.

[0139] In the first embodiment, the main body portion 21 and the water-soluble resin portion 22 of the substrate 2 are integrally formed on the modeling table T1. However, the main body portion and the water-soluble resin portion may be fabricated separately. For example, the substrate may be fabricated by fabricating a main body portion having a through-hole and a cutout, and then discharging the resin composition for the water-soluble resin into the through-hole and the cutout.

[0140] In the third embodiment, the wiring pattern 403 is configured such that, when the water-soluble resin portion 22 is not dissolved, both end portions 431b, 431c of the first wiring pattern 431 do not come into contact with the end portions of the second wiring pattern 432. Furthermore, the wiring pattern 403 is configured such that, when the water-soluble resin portion 22 is not dissolved, both end portions 431b, 431c of the first wiring pattern 431 come into contact with the end portions of the second wiring pattern 432. However, the wiring pattern may be configured such that, when the water-soluble resin portion is not dissolved, one end portion of the first wiring pattern comes into contact with one end portion of the second wiring pattern, and the other end portion of the first wiring pattern does not come into contact with the second wiring pattern.

[0141] In the third embodiment, the wiring pattern 403 is configured such that both end portions 431b, 431c of the first wiring pattern 431 are in contact with the end portions of the second wiring pattern 432. However, the wiring pattern may be configured such that a portion of the first wiring pattern other than the end portions is in contact with a portion of the second wiring pattern 432 other than the end portions.

[0142] In the first and third embodiments, the substrate 2, 102 is planar. However, the substrate may have a three-dimensional shape. For example, as shown in FIG. 10 , the substrate 602 may have a shape that conforms to the surface of the object M. This allows the surface of the substrate 602 facing the object M to easily come into contact with the surface of the object M. Therefore, when water inside the object M leaks out to the surface, part of the substrate can be more easily dissolved. In this case, the surface of the substrate 602 opposite the object M may have a shape similar to the surface shape of the object M, or may have another shape.

[0143] The present invention can be used in a device for detecting water.

[0144] DESCRIPTION OF SYMBOLS 1, 101, 201, 301, 401, 501 Water detection device 2, 102, 502, 602 Substrate 3, 103, 403, 503 Wiring pattern 4 Terminal 5, 505 Mounting portion 6 Cover layer 7 Power supply portion 8 Measurement portion 21 Main body portion 22, 122, 522 Water-soluble resin portion 31, 431 First wiring pattern 32, 432 Second wiring pattern 51 Adhesive layer 209 Communication portion 300 Water detection system 310 Receiving device 311 Determination portion 431a Central portion 431b, 431c End portion T Three-dimensional modeling device T1 Modeling table T2 Inkjet head module T3 First inkjet head T4 Second inkjet head T5 Light source

Claims

1. A water detection device that is attached to an object and detects water, comprising: a substrate; a wiring pattern formed on either one surface or the other surface of the substrate in the thickness direction; and a terminal that is electrically connected to the wiring pattern and to which a power source is connected, wherein the substrate includes a plate-shaped water-soluble resin part whose one surface in the thickness direction is exposed to one side of the substrate in the thickness direction and whose other surface in the thickness direction is exposed to the other side of the substrate in the thickness direction, and at least a portion of the wiring pattern is formed on the water-soluble resin part.

2. A water detection device as described in claim 1, wherein the wiring pattern comprises a first wiring pattern, at least a portion of which is formed on the water-soluble resin portion of the substrate, and a second wiring pattern, which is formed on the substrate other than on the water-soluble resin portion and is electrically connected to the first wiring pattern, and wherein the first wiring pattern is broken when the portion of the water-soluble resin portion on which the first wiring pattern is formed dissolves.

3. A water detection device as described in claim 1, wherein the wiring pattern comprises a first wiring pattern, at least a portion of which is formed on the water-soluble resin portion of the substrate, and a second wiring pattern, which is formed on the substrate other than on the water-soluble resin portion, and at least a portion of the portion of the first wiring pattern formed on the water-soluble resin portion is positioned so as to overlap with a portion of the second wiring pattern when viewed in the thickness direction, and the water-soluble resin portion dissolves and comes into electrical contact with the portion of the second wiring pattern, thereby being electrically connected to the second wiring pattern.

4. A water detection device according to claim 1, further comprising a mounting portion for mounting the other surface of said substrate opposite to said one surface along the surface of said object.

5. A water detection device according to claim 4, wherein the attachment portion is an adhesive layer laminated on at least a part of the other surface of the substrate.

6. A water detection device according to claim 5, further comprising a cover layer covering said one surface of said substrate.

7. A water detection device as set forth in claim 4, wherein the mounting portion has a three-dimensional shape that exposes the other surface of the substrate and can be attached to the object while holding the substrate so that the other surface is aligned with the surface of the object.

8. A water detection device according to claim 1, wherein the substrate has a three-dimensional shape, and the surface of the substrate opposite to the one surface has a shape that follows the surface shape of the object.

9. A water detection device according to claim 1, wherein the water-soluble resin portion is made of a composite resin containing an acrylic resin and a polyalkylene glycol.

10. A water detection device according to claim 9, wherein the acrylic resin is a polymer of a water-soluble monofunctional ethylenically unsaturated monomer.

11. A water detection device according to any one of claims 1 to 10, further comprising: a power supply unit electrically connected to the terminals to supply power to the wiring pattern; and a measurement unit that measures at least one of the value of the current flowing through the wiring pattern and the value of the voltage applied to the wiring pattern by the power supply unit.

12. A water detection device according to claim 11, further comprising a communication unit that transmits the measurement results of said measurement unit to an external device.

13. A water detection system comprising: the water detection device according to claim 12; and a receiving device connected to the communication unit of the water detection device by wire or wirelessly and receiving the measurement results from the communication unit, wherein the receiving device has a determination unit that determines whether or not the water detection device has detected water based on the measurement results received from the communication unit.

14. A resin composition for a water detection device used to form the water-soluble resin part in a water detection device according to any one of claims 1 to 10, the resin composition for a water detection device comprising: a water-soluble monofunctional ethylenically unsaturated monomer; a polyalkylene glycol; and a polymerization initiator.

15. A method for manufacturing a water detection device according to any one of claims 1 to 10, wherein the substrate is formed by a three-dimensional molding method using a water-soluble resin composition.

16. The method for manufacturing a water detection device according to claim 15, wherein the three-dimensional fabrication method is inkjet stereolithography.

17. A method for manufacturing a water detection device according to claim 16, wherein the substrate and the wiring pattern are formed using an inkjet type three-dimensional modeling device.

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