Gas-sensitive body, gas-sensitive element, gas detector, gas detection system, and mold odor determination method

Abstract

Provided is a gas-sensitive body suitable for detecting 2,4,6-trichloroanisole in a gas or determining the state of a gas related to 2,4,6-trichloroanisole. The gas-sensitive body 9 includes a sensitive material 23 that interacts with at least one type of substance in the gas. The sensitive material 23 contains at least one selected from the group consisting of polyisobutyl methacrylate and poly-ε-caprolactone.

Description

Gas sensitive material, gas sensitive element, gas detector, gas detection system, and musty odor determination method

[0001] The present disclosure relates to a gas sensitive material, a gas sensitive element, a gas detector, a gas detection system, and a musty odor determination method, and more specifically to: a gas sensitive material including a sensitive material that causes volume expansion by adsorbing at least one type of substance and conductive particles dispersed in the sensitive material; a gas sensitive element including the gas sensitive material; a gas detector including the gas sensitive element; a gas detection system including the gas detector; and a musty odor determination method using the gas sensitive material.

[0002] Patent Document 1 discloses that a sensitive element including an organic composition and conductive particles dispersed in the organic composition is used, and the organic composition absorbs molecules to be detected and expands, thereby increasing the electrical resistance value, to detect the molecules to be detected.

[0003] International Publication No. WO 2022 / 114158

[0004] A sensitive element as described in Patent Document 1 can be used for detection of substances in gas, etc. However, application of a sensitive element for detecting 2,4,6-trichloroanisole in gas, or for determining a gas state such as the presence or absence of musty odor caused by 2,4,6-trichloroanisole, has not been proposed. Furthermore, materials for sensitive elements suitable for these purposes have also not been proposed.

[0005] An object of the present disclosure is to provide: a gas sensitive material suitable for detecting 2,4,6-trichloroanisole in gas or determining a gas state related to 2,4,6-trichloroanisole; a gas sensitive element including the gas sensitive material; a gas detector including the gas sensitive element; a gas detection system including the gas detector; and a musty odor determination method using the gas sensitive material.

[0006] A gas sensitive material according to one aspect of the present disclosure includes a sensitive material that interacts with at least one substance in gas. The sensitive material contains at least one selected from the group consisting of polyisobutyl methacrylate and poly-ε-caprolactone.

[0007] A gas-sensitive element according to one aspect of the present disclosure comprises a gas-sensitive body and an electrode electrically connected to the gas-sensitive body.

[0008] A gas detector according to one aspect of the present disclosure comprises a gas sensor or gas sensing element and an output unit that outputs a detection signal based on the physical properties of the gas sensor.

[0009] A gas detection system according to one aspect of the present disclosure comprises a gas detector and a determination unit that generates a determination result regarding the gas based on a detection signal output by the gas detector when the gas sensor in the gas detector is exposed to the gas.

[0010] A moldy odor determination method according to one aspect of the present disclosure determines the presence or absence of a moldy odor in a gas based on changes in the physical properties of the gas sensor that occur when the gas sensor is exposed to the gas.

[0011] Figure 1 is a schematic diagram of a gas detection system according to the first embodiment of this disclosure. Figure 2 is an exploded perspective view of the sensing unit and heater in the same first embodiment. Figure 3 is a schematic cross-sectional view of a gas sensing element in the same first embodiment. Figure 4 is a schematic cross-sectional view showing the operation of a gas sensing element in the same first embodiment. Figure 5 is a flowchart of the operation of the gas detection system in the same first embodiment. Figure 6 is a schematic cross-sectional view of a gas sensing element in the second embodiment of this disclosure. Figure 7 is a schematic cross-sectional view of an example of a gas sensing element in the third embodiment of this disclosure. Figure 8 is a schematic cross-sectional view of another example of a gas sensing element in the third embodiment of this disclosure. Figure 9 is a schematic cross-sectional view of a gas sensing element in the fourth embodiment of this disclosure. Figure 10 is a schematic cross-sectional view of a gas sensing element in the fifth embodiment of this disclosure. Figure 11 is a schematic cross-sectional view showing the operation of a gas sensing element in the fifth embodiment of this disclosure.

[0012] Embodiments of this disclosure will be described with reference to the drawings. Note that the embodiments described below are only a selection of the various embodiments of this disclosure. Furthermore, the embodiments described below can be modified in various ways depending on the design, etc., as long as the objectives of this disclosure are achieved. The figures referenced below are schematic diagrams, and the shapes and dimensional ratios of the components shown in the figures do not necessarily reflect the actual shapes and dimensional ratios.

[0013] The gas-sensitive body 9 according to this embodiment includes a sensing material 23 that interacts with at least one substance in the gas (hereinafter also referred to as the target substance). The sensing material 23 contains at least one selected from the group consisting of polyisobutyl methacrylate and poly-ε-caprolactone.

[0014] The interaction between the target substance and the sensing material 23 includes, for example, the physical adsorption of the target substance onto the surface or interior of the sensing material 23, the chemical bonding of the target substance to the surface or interior of the sensing material 23, or the occurrence of a chemical reaction other than the aforementioned chemical bonding between the target substance and the sensing material 23. The interaction between the target substance and the sensing material 23 causes a change in the sensing material 23, which in turn causes a change in the physical properties of the gas sensor 9. Therefore, it is possible to detect the target substance based on the physical properties of the gas sensor 9.

[0015] The sensing material 23 includes a substance that interacts with the target substance (hereinafter also referred to as the sensing substance), and the sensing substance includes at least one selected from the group consisting of polyisobutyl methacrylate and poly-ε-caprolactone.

[0016] Polyisobutyl methacrylate and poly-ε-caprolactone each interact with 2,4,6-trichloroanisole. Therefore, in this embodiment, the target substance includes 2,4,6-trichloroanisole. Accordingly, according to this embodiment, 2,4,6-trichloroanisole can be detected using the gas-sensitive material 9. That is, when the gas-sensitive material 9 is exposed to a gas containing 2,4,6-trichloroanisole, the sensing material 23 adsorbs 2,4,6-trichloroanisole, and the physical properties of the gas-sensitive material 9 change accordingly. By utilizing this change in physical properties, 2,4,6-trichloroanisole in the gas can be detected with high accuracy.

[0017] The sensitive substance may consist of at least one selected from the group consisting of polyisobutyl methacrylate and poly-ε-caprolactone, and may further consist of substances other than polyisobutyl methacrylate and poly-ε-caprolactone.

[0018] Furthermore, the sensing material 23 may interact with only at least one substance selected from the group consisting of polyisobutyl methacrylate and poly-ε-caprolactone. In addition, the sensing material 23 may interact not only with at least one substance selected from the group consisting of polyisobutyl methacrylate and poly-ε-caprolactone, but also with at least one substance other than polyisobutyl methacrylate and poly-ε-caprolactone.

[0019] The change in the physical properties of the gas sensor 9 that occurs when the sensing material 23 interacts with the target substance is caused, for example, by changes in the sensing material 23 resulting from the interaction with the target substance. For example, the sensing material 23 undergoes a volume change when it adsorbs the target substance, and the target substance can be detected based on the change in the physical properties of the gas sensor 9 caused by this volume change of the sensing material 23. Note that the change in the sensing material 23 caused by adsorbing the target substance is not limited to a volume change, but may also be a change in mass, density, or length; a change in electrical properties of the sensing material 23 such as electrical resistivity, relative permittivity, or dielectric loss tangent; or a change in optical properties of the sensing material 23 such as color, refractive index, or light transmittance. The target substance can be detected based on the change in the physical properties of the gas sensor 9 caused by these changes in the sensing material 23.

[0020] For example, when 2,4,6-trichloroanisole is adsorbed onto at least one selected from the group consisting of polyisobutyl methacrylate and poly-ε-caprolactone in the sensing material 23, a volume change (expansion) may occur in the sensing material 23. Based on the change in the physical properties of the gas sensor 9 due to this volume change of the sensing material 23, 2,4,6-trichloroanisole can be detected. Alternatively, 2,4,6-trichloroanisole may be detected based on changes in the physical properties of the gas sensor 9 caused by changes other than the volume change of the sensing material 23. Furthermore, in this embodiment, target substances other than 2,4,6-trichloroanisole may be further detected based on the volume change of the sensing material 23, or target substances other than 2,4,6-trichloroanisole may be further detected based on changes other than the volume change of the sensing material 23.

[0021] The gas-sensitive body 9 may contain only the sensing material 23. In this case, the physical properties of the gas-sensitive body 9 are the physical properties of the sensing material 23. The gas-sensitive body 9 may further contain components other than the sensing material 23. In this case, the physical properties of the gas-sensitive body 9 are the physical properties of the combination of the sensing material 23 and the components other than the sensing material 23. For example, the gas-sensitive body 9 may further contain conductive particles 24 dispersed in the sensing material 23, as in the first embodiment described later.

[0022] Detecting a target substance includes, for example, at least one selected from the group consisting of detecting the presence or absence of the target substance, detecting the concentration of the target substance, and detecting the state of the gas caused by the target substance. In this embodiment, since the target substance includes 2,4,6-trichloroanisole, detecting the target substance includes, for example, at least one selected from the group consisting of detecting the presence or absence of 2,4,6-trichloroanisole, detecting the concentration of 2,4,6-trichloroanisole, and detecting the state of the gas caused by 2,4,6-trichloroanisole. Since 2,4,6-trichloroanisole causes a musty odor, the state of the gas caused by 2,4,6-trichloroanisole is, for example, at least one selected from the group consisting of detecting the presence or absence of a musty odor in the gas and the degree of the musty odor. That is, the gas sensor 9 is, for example, for detecting a musty odor. Mold odor detection is at least one selected from the group consisting of detecting the presence or absence of a musty odor and detecting the degree of the musty odor.

[0023] For detecting the target substance, gas-sensitive elements A1, B1, C1, D1, and E1 comprising a gas-sensitive element 9 and components other than the gas-sensitive element 9 may be used. For example, gas-sensitive elements A1, B1, C1, D1, and E1 comprising a gas-sensitive element 9 and electrodes 21 and 22 electrically connected to the gas-sensitive element 9 may be used. In this case, for example, the electrical properties of the gas-sensitive element 9 can be detected using the electrodes 21 and 22, and the target substance can be detected based on the result.

[0024] A gas detector 1 equipped with a gas sensor 9 or gas sensing elements A1, B1, C1, D1, E1 may be used to detect the target substance in the gas. For example, a gas detector 1 may be used that includes a gas sensor 9 or gas sensing elements A1, B1, C1, D1, E1 and an output unit 14 that outputs a detection signal based on the physical properties of the gas sensor 9. In this case, the target substance can be detected based on the detection signal.

[0025] A gas detection system equipped with a gas detector 1 may be used to obtain a determination result regarding the gas based on the detection result of the target substance. The gas detection system includes, for example, a gas detector 1 and a determination unit 55 that generates a determination result regarding the gas based on a detection signal output by the gas detector 1 when a gas-sensitive element 9 in the gas detector 1 is exposed to the gas. The determination result is at least one selected from the group consisting of, for example, determination of the presence or absence of 2,4,6-trichloroanisole in the gas, determination of the concentration of 2,4,6-trichloroanisole in the gas, determination of the presence or absence of a moldy odor in the gas, and determination of the degree of the moldy odor in the gas. The determination result may also include other determinations.

[0026] 1. First Embodiment 1.1. Overview of the First Embodiment The first embodiment will be described with reference to Figures 1 to 5. The gas-sensitive body 9 of the first embodiment includes a sensing material 23 that adsorbs at least one substance (target substance) and undergoes a volume change (expansion), and conductive particles 24 dispersed in the sensing material 23. The sensing material 23 contains at least one selected from the group consisting of polyisobutyl methacrylate and poly-ε-caprolactone.

[0027] Both polyisobutyl methacrylate and poly-ε-caprolactone have good adsorption performance for 2,4,6-trichloroanisole. Therefore, when the gas-sensitive body 9 is exposed to a gas containing 2,4,6-trichloroanisole, the sensing material 23 adsorbs 2,4,6-trichloroanisole and expands, and the electrical resistivity of the gas-sensitive body 9 increases accordingly. By utilizing this change in electrical resistivity, it is possible to accurately detect 2,4,6-trichloroanisole in the gas or to determine the state of the gas caused by 2,4,6-trichloroanisole.

[0028] The gas-sensitive element Ax of the first embodiment comprises a gas-sensitive body 9 and two electrodes 21 and 22 electrically connected to the gas-sensitive body 9.

[0029] Therefore, by utilizing the change in electrical resistance between the two electrodes 21 and 22, it is possible to accurately determine the state of the gas, such as detecting 2,4,6-trichloroanisole in the gas or determining whether or not there is a musty odor caused by 2,4,6-trichloroanisole.

[0030] The gas detector 1 of the first embodiment includes a gas-sensitive element Ax and an output unit 14 that outputs a detection signal based on the electrical resistance value between two electrodes 21 and 22 in the gas-sensitive element Ax.

[0031] Therefore, by utilizing the detection signal, it is possible to accurately determine the state of the gas, such as detecting 2,4,6-trichloroanisole in the gas or determining whether or not there is a moldy odor caused by 2,4,6-trichloroanisole.

[0032] The gas detection system of the first embodiment includes a gas detector 1 and a determination unit 55 that generates a determination result regarding the gas based on a detection signal output by the gas detector 1 when the gas-sensitive element 9 in the gas detector 1 is exposed to the gas. Therefore, it is possible to obtain determination results regarding the state of the gas, such as the presence or absence of a musty odor related to 2,4,6-trichloroanisole in the gas.

[0033] The moldy odor detection method of the first embodiment determines the presence or absence of a moldy odor in the gas based on the change in the electrical resistivity of the gas sensor 9 that occurs when the gas sensor 9 is exposed to the gas.

[0034] Even in very small amounts, 2,4,6-trichloroanisole can cause a musty odor. However, by using the gas-sensitive body 9 of the first embodiment, the detection sensitivity of 2,4,6-trichloroanisole in the gas can be increased. Therefore, the presence or absence of a musty odor in the gas can be accurately determined using the gas-sensitive body 9.

[0035] 1.2. Configuration of the First Embodiment (1) Gas Sensitor The gas sensitive body 9 comprises a sensing material 23 and conductive particles 24 dispersed in the sensing material 23 (see Figure 3). The sensing material 23 undergoes volume expansion by adsorbing at least one substance. The sensing material 23 contains a receptive substance that adsorbs at least one substance as a sensing material. This type of gas sensitive body 9 is called a chemoresistic sensor or chemosensitive resistor. When the gas sensitive body 9 is exposed to a gas containing molecules 8 of a substance that the receptive substance can adsorb, the volume of the sensing material 23 expands as the receptive substance adsorbs molecules 8 of the substance in the gas (see Figures 3 and 4). As a result, the distance between the conductive particles 24 in the gas sensitive body 9 increases, and consequently, the electrical resistivity of the gas sensitive body 9 increases. This change in the electrical resistivity of the gas sensitive body 9 can be used to detect substances in the gas, etc.

[0036] The acceptor is, for example, an organic material capable of adsorbing at least one substance and undergoing volume expansion. The acceptor includes, for example, OV-17, OV-22, OV-25, OV-225, OV-330, SILAR-5CP, SILAR-7CP, and OV-275, manufactured by Shinwa Chemical Co., Ltd., which are column packing materials for chromatography, and at least one selected from the group consisting of polystyrene, poly(4-tert-butylstyrene), poly(butyl methacrylate), polyvinyl formal, poly(ethylene succinate), and poly(vinylidene fluoride). The acceptor is not limited to the above.

[0037] The conductive particles 24 include, for example, at least one material selected from the group consisting of carbon materials such as carbon black, conductive polymers, metals, metal oxides, semiconductors, superconductors, and complex compounds.

[0038] The shape of the gas-sensitive element 9 is, for example, a film, but is not limited to this.

[0039] (2) Gas Sensitive Element The gas sensitive element Ax comprises a gas sensor 9 and two electrodes 21 and 22 (first electrode 21 and second electrode 22) electrically connected to the gas sensor 9 (see Figure 3). The first electrode 21 and the second electrode 22 are arranged on an electrically insulating substrate 20 with a gap between them. The gas sensor 9 is arranged on the substrate 20 so as to cover the first electrode 21 and the second electrode 22.

[0040] When the gas-sensitive element 9 adsorbs a substance in the gas, its electrical resistivity changes, and the electrical resistance between the first electrode 21 and the second electrode 22 changes accordingly. This change in electrical resistance can be used to detect substances in the gas, for example.

[0041] (3) Gas detector The gas detector 1 comprises a sensor unit 10, an output unit 14, a supply unit 6, and a blower 7. The sensor unit 10 comprises a sensor chamber 11, a sensing unit 2, a heater 3, a temperature and humidity sensor 4, an introduction path 12, and an outlet path 13 (see Figure 1). The sensing unit 2 comprises a plurality of gas sensing elements Ax.

[0042] The sensor chamber 11 has an internal space. The inlet path 12 and the outlet path 13 are connected to the sensor chamber 11 so as to lead to the internal space of the sensor chamber 11.

[0043] The sensor chamber 11 contains a sensing unit 2, a heater 3, and a temperature and humidity sensor 4.

[0044] The sensing section 2 includes a substrate 20 and a plurality of gas sensing elements Ax supported by the substrate 20. In FIG. 2, the sensing section 2 includes 16 gas sensing elements Ax, but the number of the sensing section 2 is not limited thereto. Further, in FIG. 2, the plurality of gas sensing elements Ax are arranged in a matrix, but the arrangement method of the gas sensing elements Ax is not limited thereto. Each gas sensitive body 9 of the plurality of gas sensing elements Ax has different sensing characteristics from each other. "Different sensing characteristics" means that the degree of change in the electrical resistivity of the gas sensitive body 9 when the gas sensitive body 9 adsorbs a substance is different. For example, among the respective gas sensitive bodies 9 of the plurality of gas sensing elements Ax, if at least one of the type of receptive substance contained in the sensitive material 23, the type of conductive particles 24, and the ratio of the receptive substance to the conductive particles 24 is different, the sensing characteristics of the respective gas sensitive bodies 9 of the plurality of gas sensing elements Ax can be different from each other.

[0045] Conductive wiring is disposed on the substrate 20, and the conductive wiring includes a first electrode 21 and a second electrode 22 in each gas sensing element Ax.

[0046] The heater 3 heats the gas sensitive body 9. The heater 3 is disposed so as to overlap the substrate 20 of the sensing section 2. The heater 3 includes, for example, a substrate 32 and an electric heating wiring 33 supported by the substrate 32 (see FIG. 2). The electric heating wiring 33 is, for example, a platinum wiring.

[0047] The temperature and humidity sensor 4 is disposed in the sensor chamber 11. The temperature and humidity sensor 4 outputs an output signal corresponding to the temperature and humidity of the gas inside the sensor chamber 11.

[0048] The output unit 14 outputs a detection signal corresponding to the electrical resistance value between the first electrode 21 and the second electrode 22 in each of the plurality of gas sensing elements Ax. The output unit 14 includes, for example, a measurement circuit that generates an analog signal corresponding to the electrical resistance value between the first electrode 21 and the second electrode 22, a transducer that converts the analog signal to generate the detection signal, and an output terminal for outputting the detection signal to the outside. The output unit 14 may include a transmission antenna for wirelessly transmitting the detection signal to the outside.

[0049] The supply unit 6 selectively supplies, for example, a carrier gas that does not contain the target to be detected and a carrier gas that contains the target to be detected to the sensor chamber 11. The supply unit 6 includes, for example, a carrier gas source such as a cylinder that stores the carrier gas and sends this carrier gas to the introduction passage 12, and an incorporation unit that mixes a sample containing the target to be detected into the carrier gas. The carrier gas is, for example, an inert gas such as nitrogen or air, but is not limited to these. The sample is, for example, a gas, liquid, or solid containing the target to be detected. The incorporation unit is, for example, an inlet or autosampler for injecting a liquid sample into the carrier gas, or a vent container for volatilizing a liquid or solid sample and mixing it into the carrier gas. The supply unit 6 can send carrier gas without sample incorporation to the introduction passage 12, or carrier gas with sample incorporation to the introduction passage 12. The supply unit 6 may also be configured to supply a gaseous sample collected externally directly to the sensor chamber 11 without mixing it with the carrier gas. The supply unit 6 also includes a flow rate adjustment unit that adjusts the flow rate of the gas sent from the supply unit 6 to the introduction path 12. The flow rate adjustment unit is, for example, a mass flow controller.

[0050] The blower 7 generates a gas flow from the supply unit 6 through the inlet passage 12 and the sensor chamber 11 to the outlet passage 13 in the sensor unit 10. The blower 7 is, for example, a pump or a fan. In Figure 1, the blower 7 is located in the outlet passage 13, but the position of the blower 7 is not limited to this.

[0051] (4) Gas detection system The gas detection system comprises a gas detector 1 and a control unit 5 (see Figure 1).

[0052] The control unit 5 comprises a processing unit 50, a temperature control unit 51, a storage unit 52, a display unit 57, and a flow rate control unit 58.

[0053] The memory unit 52 includes one or more storage devices. The storage devices are, for example, RAM, ROM, or EEPROM. The memory unit 52 stores a trained model MD1, etc., which the determination unit 55 in the processing unit 50 uses to generate a determination result. The trained model MD1 is a machine learning product that uses training data consisting of, for example, a combination of the state of the gas and a detection signal output by the gas detector 1 when the sensing unit 2 is exposed to the gas. The state of the gas is the state of the gas corresponding to the determination result, and is, but is not limited to, at least one of the following: the type and concentration of substances contained in the gas, the presence or absence and degree of odor of the gas, and the presence or absence and degree of effect of the odor of the gas on a person's mind.

[0054] The processing unit 50, temperature control unit 51, and flow rate control unit 58 are control circuits that control the operation of the gas detection system. The processing unit 50, temperature control unit 51, and flow rate control unit 58 may be composed of a common control circuit, or they may each be composed of different control circuits. The processing unit 50, temperature control unit 51, and flow rate control unit 58 (hereinafter also referred to as the processing unit 50, etc.) can be implemented, for example, by a computer system including one or more processors (microprocessors) and one or more memories. That is, one or more processors function as the processing unit 50, etc. by executing one or more programs (applications) stored in one or more memories. The programs are pre-recorded in the memory or storage unit 52 of the processing unit 50, etc., but may also be provided via telecommunication lines such as the Internet, or recorded on non-temporary recording media such as memory cards.

[0055] As shown in Figure 1, the processing unit 50 includes an acquisition unit 53, a learning unit 54, a determination unit 55, and an output unit 56. In Figure 1, the acquisition unit 53, learning unit 54, determination unit 55, and output unit 56 do not represent actual physical configurations, but rather represent functions realized by the processing unit 50.

[0056] The acquisition unit 53 acquires the detection signal output by the gas detector 1.

[0057] The learning unit 54 generates a trained model MD1 based on training data. That is, the learning unit 54 is responsible for the learning phase and can generate a trained model MD1 using the gas detection system. For example, the learning unit 54 stores data of combinations of detection signals and gas states acquired by the acquisition unit 53 as training data and generates a trained model MD1 based on the training data. In other words, the learning unit 54 uses the training data acquired by the gas detection system to train an artificial intelligence program (algorithm) to learn the relationship between detection signals and gas states. The artificial intelligence program is a machine learning model, such as a random forest or a neural network. The learning unit 54 generates a trained model MD1 by, for example, having a neural network perform machine learning (e.g., deep learning) with the training data and stores it in the storage unit 52. The learning unit 54 may improve the performance of the trained model MD1 by retraining it using newly collected training data from the acquisition unit 53 after generating the trained model MD1.

[0058] The determination unit 55 is responsible for the so-called inference phase. The determination unit 55 uses the trained model MD1 stored in the memory unit 52 to generate a determination result regarding the state of the gas based on the detection signal acquired by the acquisition unit 53. Specifically, the determination unit 55 generates a determination result regarding the state of the gas by inputting the detection signal data into the trained model MD1. In the first embodiment, since the sensing unit 2 includes a plurality of gas-sensitive elements Ax, the determination unit 55 generates a determination result regarding the state of the gas based on the detection signal based on the electrical resistivity of each of the plurality of gas-sensitive elements Ax exposed to the gas. This can improve the accuracy of the determination.

[0059] It should be noted that the gas detection system is not required to include a learning unit 54; the determination unit 55 may perform the inference phase using a pre-trained model MD1 generated by an external computer system.

[0060] The determination unit 55 may correct the determination result based on the detection signal output by the temperature and humidity sensor 4.

[0061] The output unit 56 outputs the judgment result of the determination unit 55. Specifically, the output unit 56 displays the judgment result of the determination unit 55 on the display unit 57 by outputting the judgment result of the determination unit 55 to the display unit 57. Note that the output of the judgment result by the output unit 56 is not limited to displaying it on the display unit 57; the judgment result may also be output as sound using a buzzer or speaker.

[0062] The temperature control unit 51 heats the gas-sensitive element 9 by activating the heater 3 and cools the gas-sensitive element 9 by stopping the heater 3. For example, the temperature control unit 51 activates the heater 3 by supplying power to it and stops the heater 3 by stopping the power supply to it.

[0063] The flow rate control unit 58 adjusts the flow rate of the gas supplied to the sensing unit 2 by controlling the flow rate adjustment unit of the supply unit 6.

[0064] The display unit 57 displays the judgment result, etc. The display unit 57 includes, for example, a display device such as a liquid crystal display.

[0065] In the first embodiment, the processing unit 50, the temperature control unit 51, and the flow rate control unit 58 include a computer system. The computer system mainly consists of a processor and memory as hardware. The functions of the gas detection system in this disclosure are realized by the processor executing a program recorded in the memory of the computer system. The program may be pre-recorded in the memory of the computer system, provided via a telecommunications line, or provided on a non-temporary recording medium such as a memory card, optical disk, or hard disk drive that can be read by the computer system. The processor of the computer system is composed of one or more electronic circuits including semiconductor integrated circuits (ICs) or large-scale integrated circuits (LSIs). The integrated circuits such as ICs or LSIs referred to here are named differently depending on the degree of integration, and include integrated circuits called system LSIs, VLSIs (Very Large Scale Integrations), or ULSIs (Ultra Large Scale Integrations). Furthermore, FPGAs (Field-Programmable Gate Arrays) that are programmed after the LSI is manufactured, or logic devices capable of reconfiguring junctions or circuit compartments within the LSI, can also be used as processors. Multiple electronic circuits may be integrated onto a single chip or distributed across multiple chips. Multiple chips may be integrated into a single device or distributed across multiple devices. The computer system referred to here includes a microcontroller having one or more processors and one or more memories. Therefore, the microcontroller also consists of one or more electronic circuits, including semiconductor integrated circuits or large-scale integrated circuits.

[0066] Furthermore, it is not essential for a gas detection system to have multiple functions integrated into a single housing; the components of a gas detection system may be distributed across multiple housings. Moreover, at least some of the functions of the gas detection system, for example, some of the functions of the control unit 5, may be implemented by the cloud (cloud computing), etc.

[0067] 1.3. Details of the First Embodiment In the first embodiment, the sensing material 23 in the gas sensor 9 of at least one gas sensing element A1 included in a plurality of gas sensing elements Ax contains at least one selected from the group consisting of polyisobutyl methacrylate and poly-ε-caprolactone. That is, the receiving substance contained in the sensing material 23 contains at least one selected from the group consisting of polyisobutyl methacrylate and poly-ε-caprolactone.

[0068] Both polyisobutyl methacrylate and poly-ε-caprolactone exhibit high adsorption capacity for 2,4,6-trichloroanisole and undergo volume expansion upon adsorption. Therefore, if the gas-sensitive material 9 includes at least one selected from the group consisting of polyisobutyl methacrylate and poly-ε-caprolactone, the electrical resistivity of the gas-sensitive material 9 can change significantly when exposed to 2,4,6-trichloroanisole. Consequently, accurate determinations related to 2,4,6-trichloroanisole in the gas can be made based on the change in the electrical resistivity of the gas-sensitive material 9.

[0069] For example, the gas-sensitive element 9 and the gas-sensitive element A1 equipped therewith can be used to detect 2,4,6-trichloroanisole.

[0070] Furthermore, 2,4,6-trichloroanisole is a cause of musty odor. For this reason, the gas sensor 9 and the gas sensing element A1 equipped with it can be used to determine the presence or absence of a musty odor in the gas, or they can also be used to determine the degree of the musty odor in the gas. Even if the amount of 2,4,6-trichloroanisole in the gas is very small, the gas will have a musty odor. However, in the first embodiment, the electrical resistivity of the gas sensor 9 can change significantly in response to 2,4,6-trichloroanisole, so the presence or absence of a musty odor and the degree of its intensity can be determined with high accuracy.

[0071] Furthermore, 2,4,6-trichloroanisole can be produced by the metabolism of microorganisms attached to food and beverages. Therefore, by collecting the gas from the surroundings of food and beverages and supplying this gas to the gas-sensitive element 9, the gas-sensitive element 9 and the gas-sensitive element A1 equipped with it can be used to determine whether or not food and beverages have deteriorated and to what extent.

[0072] The gas sensing element Ax in the sensing section 2 of the gas detector 1 may contain only one or more gas sensing elements A1 containing at least one selected from the group consisting of polyisobutyl methacrylate and poly-ε-caprolactone. It is also possible that each of the multiple gas sensing elements Ax contains at least one gas sensing element A1 selected from the group consisting of polyisobutyl methacrylate and poly-ε-caprolactone. Furthermore, the receiving substance in the gas sensing element A1 may also contain substances other than polyisobutyl methacrylate and poly-ε-caprolactone.

[0073] The gas-sensitive element 9 may contain a dispersant. In this case, the sensitivity of the gas-sensitive element 9 can be increased by good dispersion of the conductive particles 24 in the sensing material 23. The dispersant is a wetting dispersant, particularly a high molecular weight compound. The wetting dispersant includes, for example, at least one selected from the group consisting of polyether-based wetting dispersants, polyester-based wetting dispersants, and cellulose-based wetting dispersants. In addition to the dispersant, the gas-sensitive element 9 may also contain a dispersion aid, such as a pigment-based dispersion aid.

[0074] The proportion of conductive particles 24 in the gas-sensitive material 9 is preferably 45% by volume or more relative to the gas-sensitive material 9. In this case, a decrease in the detection sensitivity of the gas-sensitive material 9 when it is used repeatedly can be suppressed. In particular, if the gas-sensitive material 9 is repeatedly heated and cooled by the heater 3, the gas-sensitive material 9 may deteriorate and its detection sensitivity may decrease, but if the proportion of conductive particles 24 is 45% by volume or more, the deterioration of the gas-sensitive material 9 can be suppressed. It is also preferable that the proportion of conductive particles 24 be 75% or less. In this case, a change in electrical resistivity is particularly likely to occur when the gas-sensitive material 9 adsorbs 2,4,6-trichloroanisole.

[0075] The thickness of the gas-sensitive material 9 is preferably 0.3 μm or more and 4 μm or less. In this case, a change in electrical resistivity is particularly likely to occur when the gas-sensitive material 9 adsorbs 2,4,6-trichloroanisole.

[0076] In the first embodiment, for example, the determination result generated by the determination unit 55 based on the detection signal of the gas detector 1 in the gas detection system includes the determination of whether or not 2,4,6-trichloroanisole is present in the gas. The determination result may further include the determination of the concentration of 2,4,6-trichloroanisole in the gas.

[0077] Furthermore, the determination result may include a determination of whether or not the gas has a musty odor. In this case, the presence or absence of a musty odor in the gas can be determined based on the change in the electrical resistivity of the gas sensor 9 that occurs when the gas sensor 9 is exposed to the gas, using the gas detection system. The determination result generated by the determination unit 55 may further include a determination of the intensity of the musty odor if the gas does have a musty odor. In this case, the intensity of the musty odor in the gas can be determined based on the change in the electrical resistivity of the gas sensor 9 that occurs when the gas sensor 9 is exposed to the gas, using the gas detection system.

[0078] Furthermore, when the surrounding gas of food and beverages is supplied to the sensing unit 2, the judgment result may include a determination of whether or not the food and beverages have deteriorated, or it may further include a determination of the degree of deterioration of the food and beverages. In this case, the presence or absence of deterioration and the degree of deterioration of the food and beverages can be confirmed using the gas detection system.

[0079] The judgment results may include various determinations depending on the type and amount of receptor substances contained in each of the gas receptors 9 in the multiple gas-sensitive elements Ax. For example, the judgment results may include the presence or absence of substances other than 2,4,6-trichloroanisole, or further include a determination of the concentration of these substances. The judgment results may also include a determination of the presence or absence of odors other than moldy odors in the gas, or further include a determination of the intensity of these odors. Furthermore, the judgment results may include a determination of whether or not the odor of the gas has an effect on a person's mental state and to what extent. For example, the judgment results may include a determination of whether or not the odor of the gas can make a person feel comfortable, whether or not the odor of the gas can calm a person's emotions, or whether or not the odor of the gas can make a person feel uncomfortable.

[0080] 1.4. Operation of the first embodiment An example of the operation of the gas detection system for determining the gas will be described with reference to Figure 5.

[0081] When the gas detection system starts operating, the first step is cleaning (ST1), in which the sensing unit 2 is cleaned. At this time, the supply unit 6 supplies carrier gas that does not contain the sample gas toward the sensor chamber 11, and the blower 7 operates to create a flow of carrier gas from the supply unit 6 to the sensor unit 10, through the introduction passage 12 and the sensor chamber 11, and then to the outlet passage 13. In this state, the temperature control unit 51 operates the heater 3 to heat the gas sensing element 9. The temperature control unit 51 may also control the operation of the heater 3 based on the detection signal from the temperature and humidity sensor 4 so that the temperature of the gas sensing element 9 is within a certain range. As a result, substances adsorbed on the gas sensing element 9 are released into the carrier gas and discharged outside the sensor chamber 11. This improves the detection accuracy.

[0082] Next, in the detection step (ST2), the acquisition unit 53 acquires a detection signal, which is the detection result of the target gas. At this time, the supply unit 6 supplies a carrier gas containing the substance to be detected as the target gas toward the sensor chamber 11, and the blower 7 operates to create a flow of the target gas from the supply unit 6 to the sensor unit 10, through the introduction passage 12 and the sensor chamber 11, and then to the outlet passage 13. The flow rate control unit 58 controls the flow rate adjustment unit of the supply unit 6 so that the flow rate of the target gas is constant. In this state, the acquisition unit 53 acquires the detection signal output by the output unit 14 of the gas detector 1. The acquisition unit 53 may store this detection signal data in the storage unit 52.

[0083] Next, in the determination step (ST3), the determination unit 55 generates a determination result based on the detection signal. At this time, the determination unit 55 generates a determination result regarding the state of the target gas based on the detection signal, for example, by using the learned model MD1. The determination unit 55 may correct the determination result based on the detection signal of the temperature and humidity sensor 4. As already described, the determination result may include various determinations.

[0084] Next, in the output step (ST4), the determination result from the determination step (ST3) is output. At this time, the output unit 56 outputs the determination result generated by the determination unit 55 to the display unit 57. This allows the user of the gas detection system to confirm the determination result by checking the display content of the display unit 57. In addition, in the output step (ST4), the determination result may be output to an external system, in which case the determination result can be used by the external system.

[0085] 2. Second Embodiment The second embodiment will be described with reference to Figure 6.

[0086] The gas-sensitive element B1 according to the second embodiment comprises a gas-sensitive body 9 and a quartz crystal oscillator 25. In the second embodiment, the gas-sensitive body 9 includes a sensing material 23. The gas-sensitive body 9 does not contain the conductive particles 24 in the first embodiment, but may contain them.

[0087] In the second embodiment, the sensitive material 23 undergoes a mass change by interacting with at least one substance. The sensitive material 23 contains a receptive substance that adsorbs at least one substance as a sensitive substance. Examples of the receptive substance are the same as in the first embodiment. The sensitive substance includes at least one selected from the group consisting of polyisobutyl methacrylate and poly-ε-caprolactone. The sensitive substance may further include substances other than polyisobutyl methacrylate and poly-ε-caprolactone.

[0088] The quartz oscillator 25 can be a general-purpose quartz oscillator. That is, the quartz oscillator 25 comprises, for example, a quartz crystal and two electrodes that sandwich the quartz crystal.

[0089] The gas-sensitive element 9 and the quartz oscillator 25 are stacked and integrated into one unit.

[0090] When a voltage is applied to the quartz oscillator 25, the gas sensor 9 vibrates at a frequency corresponding to the mass of the gas sensor 9. When the mass of the gas sensor 9 changes due to the adsorption of substances in the gas, the vibration frequency of the gas sensor 9 when a voltage is applied to the quartz oscillator 25 changes accordingly. This change in vibration frequency can be used, as in the first embodiment, to detect substances in the gas.

[0091] Similar to the first embodiment, a gas detector 1 and a gas detection system equipped with a gas-sensitive element B1 can also be realized. In this case, the output unit 14 of the gas detector 1 outputs a detection signal corresponding to the vibration frequency of the gas-sensitive element B1, and the determination unit 55 of the gas detection system can generate a determination result corresponding to the detection signal.

[0092] 3. Third Embodiment The third embodiment will be described with reference to Figures 7 and 8.

[0093] The gas-sensitive element C1 according to the third embodiment comprises a gas-sensitive body 9 and two electrodes 21 and 22. This gas-sensitive element C1 is mounted on a substrate 20. In the third embodiment, the gas-sensitive body 9 includes a sensing material 23. The gas-sensitive body 9 does not contain the conductive particles 24 in the first embodiment, but may contain them.

[0094] In the third embodiment, the sensitive material 23 undergoes a change in dielectric constant by interacting with at least one substance. The sensitive material 23 contains, as a sensitive substance, a receptor substance that adsorbs, for example, at least one substance. Examples of the receptor substance are the same as in the first embodiment. The sensitive substance includes at least one selected from the group consisting of polyisobutyl methacrylate and poly-ε-caprolactone. The sensitive substance may further include substances other than polyisobutyl methacrylate and poly-ε-caprolactone.

[0095] The sensing material 23 may undergo a change in its relative permittivity by adsorbing, for example, a target substance having a relative permittivity different from that of the sensing material 23. Furthermore, the sensing material 23 may undergo a volume change by adsorbing, for example, a target substance, which may result in a change in its relative permittivity. Additionally, the ease of movement of the molecules in the sensing material 23 may change by adsorbing, for example, a target substance, which may result in a change in its relative permittivity.

[0096] As shown in Figure 7, the two electrodes 21 and 22 have appropriate shapes, such as comb-like or parallel-wire-like, and are arranged on the substrate 20. The gas-sensitive body 9 is arranged on the substrate 20 so as to cover the two electrodes 21 and 22, and thus the gas-sensitive body 9 and the two electrodes 21 and 22 are electrically connected.

[0097] As shown in Figure 8, the two electrodes 21 and 22 may be arranged so as to sandwich the sensing material 23, thereby electrically connecting the gas sensing body 9 and the two electrodes 21 and 22. In this case, for example, one electrode 21 (first electrode 21), the gas sensing body 9, and the other electrode 22 (second electrode 22) are stacked on the substrate 20 in this order. The second electrode 22 has, for example, a hole 221 that allows the gas sensing body 9 to pass through to the outside, and the gas sensing body 9 can be exposed to gas through this hole 221. The second electrode 22 is, for example, a plate, film, or mesh having the hole 221.

[0098] When an AC voltage is applied between the two electrodes 21 and 22, and the sensing material 23 adsorbs a substance in the gas, the AC impedance between the two electrodes 21 and 22 changes due to the change in the relative permittivity of the sensing material 23, and as a result, the current value flowing between the electrodes 21 and 22 changes. In other words, the change in relative permittivity can be measured based on the change in current value. This change in relative permittivity, AC impedance, and change in current value can be used, as in the first embodiment, to detect a substance in the gas.

[0099] Similar to the first embodiment, a gas detector 1 and a gas detection system equipped with a gas-sensitive element C1 can also be realized. In this case, the output unit 14 of the gas detector 1 outputs a detection signal corresponding to the relative permittivity of the gas-sensitive material 9 in the gas-sensitive element C1, and the determination unit 55 of the gas detection system can generate a determination result corresponding to the detection signal.

[0100] 4. The fourth embodiment will be described with reference to Figure 9.

[0101] The gas-sensitive element D1 according to the fourth embodiment comprises a gas-sensitive body 9, a prism 26, and a metal film 27. In the fourth embodiment, the gas-sensitive body 9 includes a sensing material 23. The gas-sensitive body 9 does not contain the conductive particles 24 in the first embodiment, but may contain them.

[0102] In the fourth embodiment, the sensitive material 23 undergoes a change in refractive index by interacting with at least one substance. The sensitive material 23 contains, for example, a receptive substance that adsorbs at least one substance as a sensitive substance. Examples of the receptive substance are the same as in the first embodiment. The sensitive substance includes at least one selected from the group consisting of polyisobutyl methacrylate and poly-ε-caprolactone. The sensitive substance may further include substances other than polyisobutyl methacrylate and poly-ε-caprolactone.

[0103] The sensitive material 23 may undergo a change in refractive index by adsorbing, for example, a target substance having a different refractive index than the sensitive material 23. Furthermore, the sensitive material 23 may undergo a volume change by adsorbing, for example, a target substance, which may result in a change in refractive index. Additionally, the sensitive material 23 may undergo a change in the mobility of its molecules by adsorbing, for example, a target substance, which may result in a change in its refractive index.

[0104] The prism 26, the metal film 27, and the gas-sensitive element 9 are stacked in this order.

[0105] In the fourth embodiment, the change in refractive index of the gas sensor 9 can be measured by surface plasmon resonance. Specifically, when light is incident on the prism 26 from outside the gas sensor element D1 and this light undergoes total internal reflection at the interface between the prism 26 and the metal film 27, an evanescent wave is generated on the surface of the metal film 27. The resonance angle at which the surface plasmon generated on the metal film 27 is maximized changes depending on the refractive index of the region on the metal film 27 (where the evanescent wave exists). Therefore, the change in refractive index of the gas sensor 9 can be measured based on the change in the resonance angle at which the surface plasmon is maximized. This change in refractive index and the change in the resonance angle at which the surface plasmon is maximized can be used, as in the first embodiment, to detect substances in a gas.

[0106] Similar to the first embodiment, a gas detector 1 and a gas detection system equipped with a gas-sensitive element D1 can also be realized. In this case, the output unit 14 of the gas detector 1 outputs a detection signal corresponding to the refractive index of the gas-sensitive element 9, and the determination unit 55 of the gas detection system can generate a determination result corresponding to the detection signal.

[0107] 5. Fifth Embodiment The fifth embodiment will be described with reference to Figures 10 and 11.

[0108] The gas-sensitive element E1 according to the fifth embodiment comprises a gas-sensitive body 9 and a piezoresistive cantilever substrate 28. In the fifth embodiment, the gas-sensitive body 9 includes a sensing material 23. The gas-sensitive body 9 does not contain the conductive particles 24 in the first embodiment, but may contain them.

[0109] In the fifth embodiment, the sensitive material 23 undergoes a volume change by interacting with at least one substance. The sensitive material 23 contains, for example, a receptive substance that adsorbs at least one substance as a sensitive substance. Examples of the receptive substance are the same as in the first embodiment. The sensitive substance includes at least one selected from the group consisting of polyisobutyl methacrylate and poly-ε-caprolactone. The sensitive substance may further include substances other than polyisobutyl methacrylate and poly-ε-caprolactone.

[0110] The gas-sensitive element 9 and the piezoresistive cantilever substrate 28 are stacked in this order.

[0111] In the fifth embodiment, when the sensing material 23 of the gas-sensitive element 9 adsorbs a substance, causing a volume change, the piezoresistive cantilever substrate 28 deforms and generates a voltage. Therefore, the volume change of the gas-sensitive element 9 can be measured based on the voltage generated by the piezoresistive cantilever substrate 28. This volume change and voltage can be used, as in the first embodiment, to detect substances in a gas.

[0112] Similar to the first embodiment, a gas detector 1 and a gas detection system equipped with a gas-sensitive element E1 can also be realized. In this case, the output unit 14 of the gas detector 1 outputs a detection signal corresponding to the volume change of the gas-sensitive body 9, and the determination unit 55 of the gas detection system can generate a determination result corresponding to the detection signal.

[0113] 6. The first to fifth modified embodiments are only a part of the various forms included in this disclosure. The embodiments can be modified in various ways depending on the design, etc., as long as they achieve the objectives of this disclosure. Furthermore, functions similar to those of a gas detection system may be embodied in a detection method, a computer program, or a non-temporary recording medium on which a program is stored.

[0114] In the first embodiment, the gas detector 1 comprises a plurality of gas-sensitive elements Ax, but the gas detector 1 may also comprise only one gas-sensitive element A1 comprising a gas-sensitive body 9 containing at least one selected from the group consisting of polyisobutyl methacrylate and poly-ε-caprolactone.

[0115] The configuration of the heater 3 is not limited to the first embodiment. Furthermore, the heater 3 may also have a cooling function, that is, the heater 3 may also function as a cooler. For example, the heater 3 may include a Peltier element.

[0116] In the first embodiment, the determination unit 55 directly generates a determination result from the detection signal. However, it may also generate the difference between the detection signal data and the reference data as difference data, and generate the determination result from this difference data using the trained model MD1. The reference data is, for example, the detection signal data when the gas detector 1 detects a carrier gas that does not contain the sample gas. In this case, for example, after the cleaning step (ST1) and before the detection step (ST2), the acquisition unit 53 acquires the reference data in the reference acquisition step. At this time, the supply unit 6 supplies the carrier gas that does not contain the sample gas as the reference gas toward the sensor chamber 11, and the blower 7 operates to create a flow of reference gas from the supply unit 6 to the sensor unit 10, through the introduction path 12 and the sensor chamber 11, and outflow path 13. In this state, the acquisition unit 53 acquires the detection signal, which is the detection result of the reference gas. The acquisition unit 53 stores this detection signal data in the storage unit 52 as reference data.

[0117] In the gas detection system, during the detection step (ST2), the acquisition unit 53 may acquire the detection signal from the gas detector 1 via a network.

[0118] In the gas detection system of the first embodiment, the trained model MD1 is stored in the storage unit 52 of the gas detection system. However, the gas detection system may generate the judgment result using a trained model located on the cloud. That is, the judgment unit 55 of the gas detection system inputs the detection signal from the gas detector 1 to the trained model on the cloud. In other words, the trained model on the cloud performs judgment processing using the detection signal acquired via the network and transmits the judgment result to the judgment unit 55. Thus, the judgment unit 55 may generate the judgment result by acquiring the judgment result from the trained model on the cloud.

[0119] Alternatively, a server having the functions of the control unit 5 may acquire a detection signal from the gas detector 1 via a network, and the determination unit 55 may perform determination processing using the detection signal. In this case, the server having the functions of the processing unit 50 may acquire the detection signal from the gas detector 1 in real time and perform determination processing, or it may acquire time-series data of the detection signal from the gas detector 1 from a data server or the like that stores time-series data of the detection signal from the gas detector 1 and perform determination processing.

[0120] Examples of the present disclosure are presented below. However, the present disclosure is not limited to the examples described below.

[0121] A dispersion with a solid content of 30-40 mg / mL was prepared by mixing an acceptor substance, carbon black (manufactured by Mitsubishi Chemical Corporation, product name #2300, average particle size 15 nm), a polymeric wetting and dispersing agent containing carbonyl groups, a dispersion aid (Synagist; product name El-N6S from Dispersion Materials Research Institute Co., Ltd.), and N-methyl-2-pyrrolidone (NMP).

[0122] As the acceptor substance, poly-ε-caprolactone (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) was used in Example 1, polyisobutyl methacrylate (manufactured by Tokyo Chemical Industry Co., Ltd., product code M0086) was used in Example 2, OV-17 (manufactured by Shinwa Chemical Co., Ltd.) was used in Comparative Example 1, OV-330 (manufactured by Shinwa Chemical Co., Ltd.) was used in Comparative Example 2, polyvinyl acetate was used in Comparative Example 3, polyvinyl formal was used in Comparative Example 4, and polyvinyl methyl ketone was used in Comparative Example 5. The amount of dispersant used was 50 parts by mass per 100 parts by mass of carbon black, and the amount of dispersing aid used was 0.03 parts by mass per 100 parts by mass of carbon black.

[0123] A film-like gas-sensitive material with a circular shape in plan view, having a diameter of 0.9 mm and a thickness of 1.0 to 1.6 μm was fabricated by applying a dispersion onto a substrate having two comb-shaped electrodes, covering both electrodes, and then drying it.

[0124] The volume fractions of conductive particles in the gas-sensitive material are shown in Table 1. These volume fractions were calculated from the weight ratios of each component, determined from the weight concentrations of each solid in the dispersion, and the densities of each component shown in Table 2.

[0125] Propylene glycol was prepared as a reference solution. Additionally, a sample solution was prepared by dissolving 2,4,6-trichloroanisole in propylene glycol at a concentration of 3.15 ppm.

[0126] A reference gas was prepared by passing nitrogen gas through the reference liquid. A gas-sensitive element was placed in the gas stream. In this state, the initial electrical resistance between the two electrodes was measured while the gas-sensitive element was heated to maintain a temperature of 80°C. Subsequently, the heating of the gas-sensitive element was stopped to allow it to dissipate heat, and the detected electrical resistance between the two electrodes was measured when the temperature of the gas-sensitive element reached 30°C.

[0127] Next, nitrogen gas was passed through the sample solution to prepare the gas to be detected. A gas sensor was placed in the gas flow. In this state, the initial electrical resistance between the two electrodes was measured while the gas sensor was heated to maintain a temperature of 80°C. Subsequently, the heating of the gas sensor was stopped to allow it to dissipate heat, and the detected electrical resistance between the two electrodes was measured when the temperature of the gas sensor reached 30°C.

[0128] The reference value was calculated by subtracting the initial value from the detected value when measuring the reference gas.

[0129] Furthermore, the measured value was calculated by subtracting the initial value from the detected value when measuring the target gas.

[0130] The value obtained by subtracting the reference value from the measured value was calculated as the response value to 2,4,6-trichloroanisole.

[0131] The above process for calculating response values ​​was repeated 30 times, yielding 30 response values. The mean and standard deviation of the response values ​​were calculated, and the value obtained by subtracting the standard deviation from the mean was used as the evaluation value.

[0132] Two gas receptors with the same composition were prepared, and the same test was performed on both, yielding evaluation values ​​for each. The evaluation values ​​for each of the two gas receptors are shown in "#1" and "#2" of the "Evaluation Score" column in Table 1. If the evaluation value is positive, the gas receptor can be evaluated as suitable for detecting 2,4,6-trichloroanisole.

[0133] As shown in Table 1, the gas receptor of Example 1, in which the receptor substance is poly-ε-caprolactone, and the gas receptor of Example 2, in which the receptor substance is polyisobutyl methacrylate, were confirmed to be suitable for detecting 2,4,6-trichloroanisole.

[0134]

[0135]

[0136] [Aspects] As shown in the embodiments and examples described above, this disclosure includes the following aspects.

[0137] The gas-sensitive body (9) of the first embodiment includes a sensing material (23) that interacts with at least one substance in the gas. The sensing material (23) contains at least one selected from the group consisting of polyisobutyl methacrylate and poly-ε-caprolactone.

[0138] According to this embodiment, the gas-sensitive body (9) can be used to accurately detect 2,4,6-trichloroanisole in a gas, or to determine the state of a gas related to 2,4,6-trichloroanisole.

[0139] In the second embodiment, in the first embodiment, the sensitive material (23) undergoes a volume change by adsorbing a substance.

[0140] According to this embodiment, by utilizing the volume change of the gas-sensitive element (9), detection of 2,4,6-trichloroanisole in the gas, or determination of the state of the gas related to 2,4,6-trichloroanisole, can be performed with high accuracy.

[0141] In a third embodiment, the gas-sensitive body (9) further includes conductive particles (24) dispersed in the sensing material (23) as in the first or second embodiment.

[0142] According to this embodiment, by utilizing the change in the electrical properties of the gas-sensitive element (9), the detection of 2,4,6-trichloroanisole in the gas, or the determination of the state of a gas related to 2,4,6-trichloroanisole, can be performed with high accuracy.

[0143] In the fourth embodiment, in any one of the first to third embodiments, the gas-sensitive body (9) further comprises a dispersant.

[0144] According to this embodiment, the detection sensitivity of the gas sensor (9) can be increased by improving the dispersibility of the conductive particles (24) in the gas sensor (9).

[0145] In the fifth embodiment, in any one of the first to fourth embodiments, the ratio of conductive particles (24) to gas-sensitive material (9) is 45% by volume or more.

[0146] According to this embodiment, the decrease in detection sensitivity when the gas-sensitive element (9) is used repeatedly can be suppressed.

[0147] In the sixth embodiment, in any one of the first to fifth embodiments, the gas-sensitive element (9) is for detecting mold odor.

[0148] According to this embodiment, the musty odor caused by 2,4,6-trichloroanisole in the gas can be detected with high accuracy using the gas-sensitive element (9).

[0149] The gas-sensitive element (A1, B1, C1, D1, E1) according to the seventh embodiment comprises a gas-sensitive body (9) according to any one of the first to fifth embodiments, and two electrodes (21, 22) electrically connected to the gas-sensitive body (9).

[0150] According to this embodiment, the detection of 2,4,6-trichloroanisole in a gas, or the determination of the state of a gas related to 2,4,6-trichloroanisole, can be performed with high accuracy using two electrodes (21, 22).

[0151] The gas detector (1) according to the eighth embodiment comprises a gas-sensitive body (9) according to any one of the first to sixth embodiments or a gas-sensitive element (A1, B1, C1, D1, E1) according to the seventh embodiment, and an output unit (14) that outputs a detection signal based on the physical properties of the gas-sensitive body (9).

[0152] According to this embodiment, based on the detection signal, the detection of 2,4,6-trichloroanisole in the gas, or the determination of the gas state related to 2,4,6-trichloroanisole, can be performed with high accuracy.

[0153] In the ninth aspect, as in the eighth aspect, the physical property is the electrical resistivity of the gas-sensitive material (9).

[0154] According to this embodiment, based on the detection signal, the detection of 2,4,6-trichloroanisole in the gas, or the determination of the gas state related to 2,4,6-trichloroanisole, can be performed with high accuracy.

[0155] In the tenth embodiment, in the eighth or ninth embodiment, the gas detector (1) comprises a plurality of gas-sensitive elements (Ax) including a gas-sensitive element (A1).

[0156] According to this embodiment, various determinations regarding the state of the gas can be made.

[0157] In the eleventh embodiment, in any one of the eighth to tenth embodiments, the gas detector (1) further comprises a heater (3) for heating a gas sensor (9).

[0158] In this embodiment, the heater (3) heats the gas-sensitive element (9), which can release substances adsorbed on the sensing material (23), thereby cleaning the gas-sensitive element (9).

[0159] In the twelfth embodiment, in any one of the eighth to eleventh embodiments, the gas detector (1) is for detecting mold odor.

[0160] According to this embodiment, the presence or absence of a moldy odor in the gas can be accurately determined using the gas detector (1).

[0161] A gas detection system according to the 13th embodiment comprises a gas detector (1) according to any one embodiment from the 8th to the 12th, and a determination unit (55) that generates a determination result regarding the gas based on a detection signal output by the gas detector (1) when a gas-sensitive element (9) in the gas detector (1) is exposed to the gas.

[0162] According to this embodiment, a determination result including the detection of 2,4,6-trichloroanisole or the determination of the state of gas related to 2,4,6-trichloroanisole can be obtained with high accuracy.

[0163] In the fourteenth embodiment, the determination result includes determining whether or not there is a moldy odor in the gas, as in the thirteenth embodiment.

[0164] According to this embodiment, it is possible to accurately determine whether or not there is a moldy odor in the gas.

[0165] The moldy odor determination method according to the 15th embodiment determines the presence or absence of a moldy odor in the gas based on the change in the physical properties of the gas sensor (9) that occurs when the gas sensor (9) of any one of the first to sixth embodiments is exposed to the gas.

[0166] According to this embodiment, it is possible to accurately determine whether or not there is a moldy odor in the gas.

[0167] In the sixteenth embodiment, as in the fifteenth embodiment, the physical property is the electrical resistivity of the gas-sensitive material (9).

[0168] According to this embodiment, it is possible to accurately determine whether or not there is a moldy odor in the gas.

[0169] A1, B1, C1, D1, E1 Gas-sensitive element Ax Gas-sensitive element 1 Gas detector 14 Output unit 21 Electrode (first electrode) 22 Electrode (second electrode) 23 Sensitive material 24 Conductive particles 3 Heater 55 Judgment unit 9 Gas-sensitive element

Claims

1. A gas-sensitive material comprising a sensing material that interacts with at least one substance in a gas, wherein the sensing material contains at least one selected from the group consisting of polyisobutyl methacrylate and poly-ε-caprolactone.

2. The gas-sensitive material according to claim 1, wherein the sensitive material undergoes a volume change by adsorbing the substance.

3. The gas-sensitive material according to claim 1, further comprising conductive particles dispersed in the sensitive material.

4. The gas-sensitive body according to claim 3, further comprising a dispersant.

5. The gas-sensitive material according to claim 3, wherein the ratio of conductive particles to the gas-sensitive material is 45% by volume or more.

6. The gas-sensitive body according to claim 1, for detecting moldy odors.

7. A gas-sensitive element comprising a gas-sensitive body according to claim 1, and an electrode electrically connected to the gas-sensitive body.

8. A gas detector comprising: a gas-sensitive body according to claim 1 or a gas-sensitive element according to claim 7; and an output unit that outputs a detection signal based on the physical properties of the gas-sensitive body.

9. The gas detector according to claim 8, wherein the physical property value is the electrical resistivity of the gas sensor.

10. The gas detector according to claim 8, comprising a plurality of gas-sensitive elements including the aforementioned gas-sensitive element.

11. The gas detector according to claim 8, further comprising a heater for heating the gas-sensitive element.

12. The gas detector according to claim 8, for detecting moldy odors.

13. A gas detection system comprising: a gas detector according to claim 8; and a determination unit that generates a determination result regarding the gas based on a detection signal output by the gas detector when the gas-sensitive element in the gas detector is exposed to the gas.

14. The gas detection system according to claim 13, wherein the determination result includes determining whether or not the gas has a moldy odor.

15. A method for determining whether a gas has a moldy odor, based on the change in the physical properties of the gas sensor that occurs when the gas sensor described in claim 1 is exposed to the gas.

16. The method for determining mold odor according to claim 15, wherein the physical property value is the electrical resistivity of the gas-sensitive material.

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