Resin composition for forming odor substance receptive layer, sensor element using the same, odor sensor, and odor measurement device

Abstract

To provide a high-sensitive chemiresistor sensor using carbon black as a filler.SOLUTION: A resin composition for chemiresistor sensors is provided, comprising a resin (A) and carbon black (B) featuring a DBP oil absorption of 300 ml / 100 g or less.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a resin composition for forming an odorant-receiving layer, and a sensor element, an odor sensor, and an odor measuring device using the same. [Background technology]

[0002] Recent advances in information processing technology have enabled the quantification of olfaction, one of the five human senses that has not yet been fully achieved through mechanical measurement. If we could somehow quantify olfaction, it would be useful in a wide range of industrial fields. For example, in the medical field, applications include nursing care, assistance, preventive diagnosis, and disease testing. In the environmental field, applications include odor management in factories, fermentation process management in biogas utilization, and wastewater treatment management. In the safety field, applications include predictive detection of disasters such as landslides and floods, and detection of engine oil and machine oil deterioration. In the food industry, applications include detecting the maturation state of ingredients such as plants and meat, process management for fermented foods such as alcoholic beverages, plant cultivation management, and quality control during food production, storage, and distribution. Furthermore, in the marketing field, applications are expected for cosmetics, body odor, fragrant environments, and product scent production. Until now, methods for detecting specific gaseous substances (environmental odor gases) have been achieved with high accuracy and sensitivity using semiconductor gas sensors. To date, methods for detecting specific gaseous substances (environmental odor gases) have been realized with high accuracy and sensitivity using semiconductor gas sensors and other methods.

[0003] The invention described in Patent Document 1 proposes a mechanism for detecting the adsorption of odor components onto the surface of a conductive polymer by replacing the semiconductor in a semiconductor gas sensor with a conductive polymer. Patent Document 1 reports that it is possible to detect odor components that are easily thermally decomposed and substances that do not undergo redox reactions on the surface of the sensor's detection part.

[0004] Furthermore, Patent Document 2 focuses on the property that the electrical resistance of a mixture of an organic polymer and a conductive material changes when exposed to an organic gas. Patent Document 2 describes that when multiple combinations of organic polymer / conductive material, each with a different organic polymer composition, are prepared from the above mixture and used as an electrical resistance array in a sensor, the electrical resistance changes differently when exposed to the same organic gas. Patent Document 2 reports that this can be used to identify odors by associating the pattern of electrical resistance change with the type of odor (= organic gas mixture).

[0005] Furthermore, Patent Document 3 reports that the response speed of the sensor can be improved by adding a plasticizer to the organic polymer.

[0006] Patent Documents 4 and 5 disclose odor measuring devices that use a resin composition containing a resin composition, a surfactant, and a conductive carbon material. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Japanese Patent Application Publication No. 11-23508 [Patent Document 2] Special Publication No. 11-503231 [Patent Document 3] Special Publication No. 2002-519633 [Patent Document 4] Patent Publication No. 2024-008838 [Patent Document 5] Patent Publication No. 2024-12146 Summary of the Invention [Problem to be solved by the invention]

[0008] The substance-receiving layer of a chemiresistor sensor contains a resin composition. This resin composition generally contains a resin and a filler. However, when high-structure carbon black is used as the filler, the sensitivity of the sensor decreases.

[0009] One aspect of the present invention has been made in view of the above-mentioned problems, and aims to provide a technique that can realize a highly sensitive chemiresistor sensor that uses carbon black as a filler. [Means for solving the problem]

[0010] The present inventors have conducted research to achieve the above object and have arrived at the present invention.

[0011] That is, the resin composition for a chemiresistor sensor according to one embodiment of the present invention contains a resin (A) and carbon black (B), and the DBP oil absorption of the carbon black (B) is 300 ml / 100 g or less. [Effects of the Invention]

[0012] According to one aspect of the present invention, a technology can be provided that can improve the odor discrimination performance in odor measurement using an odor sensor without reducing the manufacturing stability of a resin composition. [Brief explanation of the drawings]

[0013] [Figure 1] 1 is a schematic diagram showing an example of the configuration of an odor measurement device according to one embodiment of the present invention. [Figure 2] FIG. 2 is a top view showing an example of the configuration of a sensor element. [Figure 3] 3 is a cross-sectional view showing an example of the configuration of the sensor element shown in FIG. 2. FIG. [Figure 4] FIG. 2 is a top view showing an example of the configuration of a sensor element. [Figure 5] FIG. 1 is a functional block diagram showing an example of the configuration of an odor measurement device. [Figure 6]10 is a flowchart illustrating an example of a processing flow in which the estimation device generates an estimation model. [Figure 7] FIG. 1 is a functional block diagram showing an example of the configuration of an odor measurement device. [Figure 8] 10 is a flowchart showing an example of the flow of a process in which the estimation device estimates an odor substance. [Figure 9] FIG. 10 is a block diagram showing an example of the configuration of an odor measurement device according to another embodiment of the present invention. [Figure 10] FIG. 10 is a schematic diagram showing an example of the configuration of an odor measurement device according to another embodiment of the present invention. [Figure 11] FIG. 2 is a top view showing an example of the configuration of a sensor chamber. [Figure 12] FIG. 2 is a cross-sectional view showing an example of the configuration of a sensor chamber. [Figure 13] FIG. 2 is a cross-sectional view showing an example of the configuration of a sensor chamber. [Figure 14] FIG. 2 is a top view showing an example of the configuration of a sensor element of the present invention. [Figure 15] FIG. 2 is a top view showing an example of the configuration of a sensor element of the present invention. [Figure 16] 10 is a flowchart illustrating an example of the flow of a method for manufacturing a sensor element. [Figure 17] FIG. 2 is a top view illustrating an example of a substrate before slurry is applied thereto. DETAILED DESCRIPTION OF THE INVENTION

[0014] [Embodiment 1] One embodiment of the present invention will be described below, but the present invention is not limited thereto. Furthermore, unless otherwise specified in this specification, the expression "A to B" representing a range of numerical values ​​means "A or more and B or less."

[0015] In this specification, "odor substance" broadly refers to a substance that can be adsorbed onto an odor substance receiving layer. Therefore, it also includes substances that are not generally considered to be odor-causing substances. "Odor" often contains multiple odor substances that cause it, and there are also substances that are not recognized as odor substances or unknown odor substances. One embodiment of the present invention focuses on the fact that the amount of odor substance adsorbed onto an odor substance receiving layer varies depending on the type of odor substance.

[0016] In addition, even when the term "odorous substance" is simply used in this specification, it may refer to a "collection of odorous substances" that may contain multiple odorous substances, rather than an individual odorous substance.

[0017] Examples of "odor substances" include, but are not limited to, hexane, ethyl acetate, methanol, diethyl carbonate, toluene, d-limonene, bornan-2-one, cis-3-hexenol, β-phenylethyl alcohol, citral, L-carvone, γ-undecalactone, eugenol, linalyl acetate, menthol, benzaldehyde, vanillin, hexanal, ethanol, pentyl valerate, linalool, and 2-propanol.

[0018] In addition, in this specification, the term "odorant receiving layer" refers to a layer that adsorbs the odorant to be recognized. The odorant receiving layer is formed from the resin composition described above. The odorant receiving layer can be provided as part of the sensor element described below.

[0019] [1. Resin composition] A resin composition according to one embodiment of the present invention is a resin composition for a chemiresistor sensor, and contains a resin (A) and carbon black (B).

[0020] The substance receiving layer of the chemiresistor sensor contains a resin composition. The method by which the resin composition detects the target is as follows. First, the molecules of the detection target are adsorbed to the resin composition, causing the resin to expand. When the resin expands, the conductive path formed by the filler in the resin composition is cut, causing a change in the electrical resistance value of the resin composition. Based on this change in electrical resistance value, the chemiresistor sensor detects the target substance. The higher the rate of change in the electrical resistance value of the resin composition, the higher the sensitivity of the chemiresistor sensor.

[0021] Carbon black particles are fused together, and the size of the fused particles is called the structure. The higher (or larger) this structure, the more complex the shape of the carbon black. The present inventors have newly discovered the problem that when carbon black with a high structure (i.e., a more complex shape) is used as a filler, the conductive paths of the resin composition are less likely to be cut and the electrical resistance value is less likely to change, resulting in a decrease in sensor sensitivity.

[0022] In view of the above problems, the present inventors have focused on the fact that the structure of carbon black is closely related to the DBP oil absorption of carbon black, and have discovered that a sensor with improved sensitivity can be realized by using carbon black with a DBP oil absorption of a certain value or less.

[0023] DBP oil absorption is a parameter that indicates the complexity of the carbon black structure. Carbon black with a complex structure has many voids and can therefore absorb more DBP. In other words, the higher the DBP oil absorption, the higher the porosity of the carbon black and the more complex its structure.

[0024] Even when carbon black with a high DBP oil absorption is used, it is possible to increase the rate of change in the electrical resistance of the resin composition by reducing the carbon black content. However, if the resin composition contains too much resin component, it takes longer to absorb the target component, resulting in a problem of reduced sensor responsiveness.

[0025] On the other hand, when carbon black with low DBP oil absorption is used, even if the expansion coefficient of the resin composition is small, the conductive path of the resin composition is easily broken, which makes the electrical resistance value more likely to change, thereby improving the sensitivity of the resulting sensor.

[0026] Conventionally, it has been considered preferable to have a high DBP oil absorption from the viewpoint of electrical conductivity. Therefore, the use of carbon black with a low DBP oil absorption (i.e., low structure) as a filler can improve the sensitivity of the resulting sensor, which is a surprising effect that could not be predicted from conventional technology.

[0027] According to the present invention, a highly sensitive chemiresistor sensor can be realized by using carbon black (B) having a DBP oil absorption of a certain level or less.

[0028] In one embodiment, the chemiresistor sensor may be an odor sensor. In this case, the resin composition according to one embodiment of the present invention is used in an odorant-receiving layer of the odor sensor element. The resin composition can also be used to detect odorants.

[0029] <Resin (A)> Resin (A) should have film-forming properties that allow it to form an odorant-receiving layer, and it is preferable that it exhibits interactions with specific odorants, such as adsorption. Furthermore, it is preferable that resin (A) have appropriate physical properties (such as heat resistance) and chemical properties (such as compatibility with sample gases and corrosion resistance) according to the operating conditions of the odor sensor described below.

[0030] In addition, resin (A) has a viscosity of 7 to 12 (cal / cm 3 ) 1 / 2 (14.4~24.6(J / cm 3 ) 1 / 2From the viewpoint of increasing the solubility of the resin (A) in the resin composition in a process solvent (for example, the solvent (D) described below), the SP value of the resin (A) is preferably 7 or more, and more preferably 7.5 (cal / cm 3 ) 1 / 2 More preferably, it is 8 (cal / cm 3 ) 1 / 2 From the viewpoint of reducing the influence of moisture in the air on the sensor element, the SP value of the resin (A) is more preferably 11.5 (cal / cm 3 ) 1 / 2 It is preferable that the temperature is 11 (cal / cm 3 ) 1 / 2 More preferably, it is 10.5 (cal / cm 3 ) 1 / 2 It is even more preferable that:

[0031] In the present invention, the SP value is expressed as the square root of the ratio of the cohesive energy density to the molar volume, as shown below.

[0032] SP value = (ΔE / V) 1 / 2 Here, ΔE represents the cohesive energy density, and V represents the molar volume. The SP value is calculated by Robert F. Fedors et al. and is described in, for example, Polymer Engineering and Science, Vol. 14, pp. 147-154.

[0033] When resin (A) is a mixture of two or more resins, the SP value of resin (A) refers to the weight-weighted average SP value of resin (A). In other words, resin (A) may contain resins with SP values ​​outside the above range, as long as the most probable SP values ​​of the resins in (A) obtained by the weight average method are within the above range. When resin (A) is publicly known, the SP value of resin (A) may be a literature value or a catalog value.

[0034] Various known resins can be used as the resin (A). The resin (A) may be one or more types. Examples of the resin (A) include fluororesins, acrylic polymers, vinyl polymers, polyurethane resins, styrene-based resins, polyether polyols, diene polymers, and polyesters.

[0035] (Fluorine resin) Examples of fluororesins include polyvinylidene fluoride (PVDF), vinylidene fluoride-hexafluoropropylene copolymer (PVDF-HFP), tetrafluoroethylene-hexafluoropropylene copolymer (FEP), polytetrafluoroethylene (PTFE), polychlorotrifluoroethylene (PCTFE), and chlorotrifluoroethylene-ethylene copolymer (ECTFE).

[0036] Of the above-mentioned fluororesins, PVDF, PVDF-HFP, FEP, PTFE, PCTFE or ECTFE are preferred from the viewpoint of the accuracy of detecting odorous substances, and PVDF, PVDF-HFP, FEP or PTFE are more preferred.

[0037] From the viewpoint of odor discrimination performance, the relative dielectric constant (60 Hz) of the fluororesin is preferably 2.0 to 9.0, more preferably 2.3 to 9.0, and most preferably 6.8 to 9.0.

[0038] (Measurement conditions for relative permittivity) In this specification, the relative dielectric constant of the fluororesin can be measured with reference to the method described in JIS C2138 of the Japanese Industrial Standards (JIS).

[0039] Specifically, the measurement is performed by the following method. An E4908A (manufactured by Agilent Technologies, Inc.) can be used as the LCR meter. The measurement conditions can be, for example, a frequency of 1 MHz and 25°C. 1. Prepare a test piece with a diameter of 100 mm and a thickness of 1.5 mm. 2. Attach 36 mm diameter aluminum foil with tabs to the top and bottom of the test piece using a small amount of silicone grease to create electrodes. 3. Connect the electrode tabs to an LCR meter and measure the relative dielectric constant.

[0040] (acrylic polymer) Examples of acrylic polymers include (co)polymers containing alkyl (meth)acrylate as a constituent monomer. In this specification, "(meth)acrylate" refers to either acrylate or methacrylate, and "(co)polymer" refers to either homopolymer or copolymer.

[0041] Examples of constituent monomers include methyl acrylate, ethyl acrylate, propyl acrylate, butyl acrylate, pentyl acrylate, hexyl acrylate, 2-ethylhexyl acrylate, heptyl acrylate, octyl acrylate, nonyl acrylate, decyl acrylate, dodecyl acrylate, undecyl acrylate, tridecyl acrylate, tetradecyl acrylate, pentadecyl acrylate, hexadecyl acrylate, and heptadecyl acrylate. acrylate, octadecyl acrylate, nonadecyl acrylate, icosyl acrylate, henicosyl acrylate, docosyl acrylate, triicosyl acrylate, tetraicosyl acrylate, pentaicosyl acrylate, hexaicosyl acrylate, heptaicosyl acrylate, octaicosyl acrylate, nonaicosyl acrylate, triacontyl acrylate, untriacontyl acrylate, dotriacontyl acrylate, methyl methacrylate, ethyl methyl methacrylate, propyl methacrylate, butyl methacrylate, pentyl methacrylate, hexyl methacrylate, 2-ethylhexyl methacrylate, heptyl methacrylate, octyl methacrylate, nonyl methacrylate, decyl methacrylate, dodecyl methacrylate, undecyl methacrylate, tridecyl methacrylate, tetradecyl methacrylate, pentadecyl methacrylate, hexadecyl methacrylate, heptadecyl methacrylate, octadecyl methacrylate, nonadecyl methacrylate, icosyl methacrylate, henicosyl methacrylate, docosyl methacrylate, triicosyl methacrylate, tetraicosyl methacrylate, pentaicosyl methacrylate, hexaicosyl methacrylate, heptaicosyl methacrylate, octaicosyl methacrylate, nonaicosyl methacrylate, triacontyl methacrylate, untriacontyl methacrylate, and dotriacontyl methacrylate. These constituent monomers may be used alone or in combination of two or more.

[0042] A monomer containing a nitrogen atom can also be used in combination with the alkyl (meth)acrylate. With the above-described configuration, an odor sensor with good odor discrimination ability can be obtained.

[0043] Examples of the monomer containing a nitrogen atom include a vinyl compound containing at least one amide group, a vinyl compound containing at least one amino group, an alicyclic (meth)acrylate having a nitrogen atom, and an aromatic monomer having a nitrogen atom.

[0044] Examples of the solvent include toluene, xylene, methyl ethyl ketone, ethyl acetate, butyl butyrate, tetrahydrofuran, and mineral oil.

[0045] Examples of the polymerization catalyst include azo catalysts (e.g., 2,2'-azobis(2-methylbutyronitrile) and 2,2'-azobis(2,4-dimethylvaleronitrile)), peroxide catalysts (e.g., benzoyl peroxide, cumyl peroxide, and lauryl peroxide), and redox catalysts (e.g., a mixture of benzoyl peroxide and a tertiary amine). If necessary, a known chain transfer agent (e.g., an alkyl mercaptan having 2 to 20 carbon atoms) may also be used.

[0046] From the viewpoint of industrialization, the polymerization temperature is preferably 25 to 140°C, and more preferably 50 to 120°C.

[0047] (Polyurethane resin) Examples of polyurethane resins include polymers consisting of a portion derived from polyol (x) and a portion derived from polyisocyanate (y), i.e., polymers obtained by polymerizing polyol (x) and polyisocyanate (y).

[0048] The polyurethane resin may consist of one type of polyurethane resin, or may be a mixture of two or more types of polyurethane resins.

[0049] The polyol (x) may be, for example, one or more polyols selected from the group consisting of polyoxyalkylene diols (x1) and polyester diols (x2).

[0050] The polyol (x) may consist of one type of polyol, or may be a mixture of two or more types of polyol (x).

[0051] The polyoxyalkylene diol (x1) is preferably a polyester diol having an oxyalkylene group having 2 to 4 carbon atoms, and more preferably at least one selected from the group consisting of polyoxyethylene diol, polyoxypropylene diol, propylene oxide-ethylene oxide copolymer diol (random and / or block copolymer), and polytetramethylene ether glycol.

[0052] The number average molecular weight of the polyoxyalkylene diol (x1) is preferably 500 to 20,000, more preferably 1,000 to 15,000, and even more preferably 2,000 to 10,000.

[0053] The method for measuring the number average molecular weight of the polyoxyalkylene diol (x1) is not particularly limited, but for example, it is measured using gel permeation chromatography (GPC) under the following conditions: The sample to be subjected to GPC may be, for example, a filtrate obtained by dissolving the diene polymer (A) in a THF (tetrahydrofuran) solution and then filtering the THF solution through a glass filter.

[0054] Equipment (example): Tosoh Corporation HLC-8120 Column (example): 2 TSK GEL GMH6 columns (manufactured by Tosoh Corporation) Measurement temperature: 40℃ Sample solution: 0.25% by weight THF (tetrahydrofuran) solution Solution injection volume: 100μl Detector: Refractive index detector Furthermore, a calibration curve for calculating the number average molecular weight of the polyoxyalkylene diol (x1) can be prepared by the least squares method based on twelve measured number average molecular weight values ​​obtained using twelve types of standard polystyrene (TSKstandard POLYSTYRENE, manufactured by Tosoh Corporation) having different number average molecular weights (500, 1050, 2800, 5970, 9100, 18100, 37900, 96400, 190000, 355000, 1090000, or 2890000) as reference substances.

[0055] Examples of the polyester diol (x2) include polyester diols obtained by condensation of one or more diols selected from the group consisting of aliphatic diols and aromatic diols having 2 to 10 carbon atoms with one or more dicarboxylic acids selected from the group consisting of aliphatic dicarboxylic acids having 2 to 10 carbon atoms and aromatic dicarboxylic acids having 8 to 12 carbon atoms.

[0056] The number average molecular weight of the polyester diol (x2) is preferably 1,000 to 20,000, more preferably 1,500 to 15,000, and even more preferably 2,000 to 10,000. The number average molecular weight of the polyester diol (x2) can be measured by the same method as for the number average molecular weight of the polyoxyalkylene diol (x1).

[0057] Examples of the polyisocyanate (y) include aromatic polyisocyanates having 8 to 16 carbon atoms, chain aliphatic polyisocyanates having 5 to 12 carbon atoms, and alicyclic polyisocyanates having 9 to 15 carbon atoms. These polyisocyanates may have 2 to 3 or more isocyanate groups.

[0058] The polyisocyanate (y) may consist of one type of polyisocyanate or may be a mixture of two or more types of polyisocyanates.

[0059] (Polyether polyol) Examples of polyether polyols include polyethylene glycol, polypropylene glycol, polytetramethylene ether glycol, polyoxyethylene polyoxypropylene glycol, etc. These polyether polyols (A) may be used alone or in combination of two or more.

[0060] From the viewpoint of repeatability of electrical conductivity measurement, the polyether polyol is preferably polyethylene glycol, polypropylene glycol, polytetramethylene ether glycol or polyoxyethylene polyoxypropylene glycol, more preferably polyethylene glycol.

[0061] (Diene polymer) Examples of the diene polymer include isoprene polymer, butadiene polymer, chloroprene polymer, styrene-butadiene polymer, styrene-isoprene polymer, and acrylonitrile-butadiene polymer.

[0062] The diene polymer may consist of one type of polymer or may be a mixture of two or more types of polymers.

[0063] From the viewpoint of the accuracy of identifying odorous substances, it is preferable that the diene polymer be an isoprene polymer, a butadiene polymer, a styrene-butadiene polymer, a styrene-isoprene polymer, or a mixture of any two or more polymers selected from these.

[0064] The diene polymer can be obtained by, for example, a known production method, specifically, a method of obtaining a diene polymer by solution polymerization or emulsion polymerization of constituent monomers in a solvent in the presence of a polymerization catalyst.

[0065] The solvent is not particularly limited, but examples thereof include nonpolar solvents (n-hexane, n-heptane, cyclohexane, benzene, toluene, xylene, mineral oil, etc.) and polar solvents (1,4-dioxane, tetrahydrofuran, anisole, ethylene glycol dimethyl ether, 18-crown-6-ether, pyridine, N,N,N',N'-tetramethylethylenediamine, N,N'-dimethylformamide, N-methylpyrrolidone, ion-exchanged water, etc.).

[0066] The polymerization catalyst is not particularly limited, and examples thereof include alkali metal catalysts (lithium, sodium, potassium, etc.), organometallic compound catalysts (n-butyllithium, sec-butyllithium, triethylaluminum, diethylzinc, etc.), Grignard reagent catalysts (tert-butylmagnesium bromide, etc.), inorganic compound catalysts (sodium naphthalenide, potassium naphthalenide, sodium amide, known titanium catalysts, known nickel catalysts, known cobalt catalysts, etc.), inorganic peroxide catalysts (hydrogen peroxide, sodium persulfate, potassium persulfate, etc.), and redox catalysts (mixtures of hydroperoxides and divalent iron ions, etc.). If necessary, known chain transfer agents (e.g., alkyl mercaptans having 2 to 20 carbon atoms) may also be used.

[0067] The polymerization temperature in the solution polymerization or emulsion polymerization is preferably 0 to 140°C, more preferably 40 to 130°C, from the viewpoint of industrialization.

[0068] (polyester) Examples of polyesters include polymers comprising a moiety derived from a polycarboxylic acid and a moiety derived from a polyhydric alcohol, that is, polymers obtained by polymerizing a polycarboxylic acid and a polyhydric alcohol.

[0069] The polyester may consist of one type of polyester or may be a mixture of two or more types of polyester.

[0070] Examples of the polycarboxylic acid include one or more polycarboxylic acids selected from the group consisting of dicarboxylic acids and trivalent or higher polycarboxylic acids.

[0071] Examples of the dicarboxylic acid include aromatic dicarboxylic acids having 8 to 12 carbon atoms (phthalic acid, isophthalic acid, terephthalic acid, 2,6-naphthalenedicarboxylic acid, etc.), alkane dicarboxylic acids having 4 to 12 carbon atoms (succinic acid, adipic acid, sebacic acid, 1,12-dodecanedioic acid, etc.), and alkene dicarboxylic acids having 4 to 12 carbon atoms (alkenyl succinic acid, maleic acid, fumaric acid, citraconic acid, mesaconic acid, etc.). Examples of the alkenyl succinic acid include dodecenyl succinic acid. The dicarboxylic acid may be one type of dicarboxylic acid or a mixture of two or more types of dicarboxylic acids.

[0072] When the polycarboxylic acid contains a dicarboxylic acid, from the viewpoint of stability in repeated measurements, the dicarboxylic acid is preferably at least one selected from the group consisting of aromatic dicarboxylic acids having 8 to 12 carbon atoms, alkane dicarboxylic acids having 4 to 12 carbon atoms, and alkene dicarboxylic acids having 4 to 12 carbon atoms, and more preferably at least one selected from the group consisting of phthalic acid, isophthalic acid, terephthalic acid, succinic acid, adipic acid, maleic acid, and fumaric acid.

[0073] Examples of the trivalent or higher polycarboxylic acid include aromatic carboxylic acids having 9 to 12 carbon atoms (trimellitic acid, pyromellitic acid, etc.). The trivalent or higher polycarboxylic acid is preferably a trivalent polycarboxylic acid, and particularly preferably trimellitic acid.

[0074] In the above-described method for producing a polyester, the polycarboxylic acid and the polyhydric alcohol may be reacted using an organic solvent having a boiling point of 100° C. or higher as the reaction solvent. Examples of the organic solvent having a boiling point of 100° C. or higher include toluene, xylene, N-methylpyrrolidone, dimethylformamide, and 1,4-dioxane.

[0075] <Carbon black (B)> A resin composition according to one embodiment of the present invention contains carbon black (B) having a DBP oil absorption of 300 ml / 100 g or less. When the resin composition contains the carbon black (B), the sensitivity of the sensor is improved.

[0076] The DBP oil absorption of carbon black (B) is 300 ml / 100 g or less, preferably 250 ml / 100 g or less, more preferably 200 ml / 100 g or less, even more preferably 150 ml / 100 g or less, and particularly preferably 100 ml / 100 g or less. The lower the DBP oil absorption of carbon black (B), the better, but it may be, for example, 10 ml / 100 g or more. If the oil absorption of carbon black (B) is within the above range, it can be said that the surface structure of carbon black (B) is not well developed, thereby improving sensor sensitivity. In this specification, the DBP oil absorption of carbon black (B) is measured by a method in accordance with JIS K 6217-4.

[0077] The shape of the carbon black (B) is not particularly limited and may be, for example, fibrous or spherical. Since there is no particular correlation between DBP oil absorption and shape, any shape of carbon black (B) can be used as long as it satisfies the DBP oil absorption requirement.

[0078] For example, when the carbon black (B) is fibrous, the fiber diameter may be, for example, 0.1 to 10 μm, or 0.1 to 5 μm, and the fiber length may be, for example, 0.1 to 10 μm, or 1 to 10 μm.

[0079] For example, when the carbon black (B) is spherical, the primary particle size may be, for example, 10 nm to 200 nm, 20 nm to 150 nm, or 30 to 70 nm.

[0080] From the viewpoint of dispersion stability in the resin composition, the carbon black (B) preferably has a particle size of 100 nm or less. The particle size of the carbon black can be determined by a known method. The particle size of the carbon black can be measured by observing the carbon black with a transmission electron microscope (TEM) and analyzing the image using an image processing device (for example, a digital microscope VHX-700F manufactured by Keyence Corporation). When the carbon black is a known or commercially available product, the particle size, specific surface area, and pH may be values ​​from a literature or catalog.

[0081] The specific surface area of ​​carbon black (B) is 100m 2 / g or less, 75m 2 / g or less, 50m 2 The specific surface area of ​​the carbon black (B) may be, for example, 20 m 2 / g or more.

[0082] In the resin composition, the content of carbon black (B) is preferably 10 to 85% by weight, relative to 100% by weight of the total of resin (A) and carbon black (B). The content of carbon black (B) is more preferably 15 to 80% by weight, and even more preferably 20 to 75% by weight. When the content of carbon black (B) is 5% by weight or more, the sensor is less susceptible to the effects of variations in the carbon black content in the resin composition, improving the stability of the sensor. When the content of carbon black (B) is 70% by weight or less, the carbon black is more easily dispersed in the resin composition, making it less likely for sedimentation to occur during coating, improving the stability of the sensor.

[0083] Commercially available carbon black products may be used, such as Ketjenblack EC (trade name, manufactured by Akzo, Netherlands), Ketjenblack EC-300J (trade name, manufactured by Lion Specialty Chemicals Co., Ltd.), Ketjenblack EC-600JD (trade name, manufactured by Lion Specialty Chemicals Co., Ltd.), Seast G116, 116 (trade names, manufactured by Tokai Carbon Co., Ltd.), Nitelon #10 (trade name, manufactured by Nippon Steel Chemical Co., Ltd.), Denka Black (trade name, manufactured by Denki Kagaku Kogyo Kabushiki Kaisha), JB-3 (trade name, manufactured by Nippon Graphite Industries Co., Ltd.), JCP-P6B (trade name, manufactured by JFE Chemical Corporation), and SUPER C-65 (trade name, manufactured by MTI Corporation, USA).

[0084] <Optional ingredients> The resin composition may further contain components other than the resin (A) and carbon black (B) described above, as long as the effects of the present invention are obtained. Examples of other components include a solvent (D) and a plasticizer (P). The other components can be suitably used as long as both the effects of the present invention and the effects of the other components are obtained.

[0085] The solvent (D) can be added to the resin composition from the viewpoint of improving the dispersibility of the carbon black (B) in the resin composition or improving the coatability of the resin composition. Examples of the solvent (D) include N-methylpyrrolidone, propylene glycol monomethyl ether acetate, ethyl acetate, N,N-dimethylformamide, N,N-dimethylacetamide, toluene, and xylene.

[0086] The content of the solvent (D) in the resin composition can be determined appropriately from the above viewpoints. For example, from the viewpoint of the viscosity of the resin composition, the content of the solvent (D) in the resin composition is preferably 100 to 1000 parts by weight per 100 parts by weight of the total of the resin (A) and the carbon black (B).

[0087] A plasticizer (P) can be added to the resin composition to fine-tune the characteristics of the odor sensor. Examples of plasticizers (P) include Sunflex (registered trademark) EB-300 (manufactured by Sanyo Chemical Industries, Ltd., ester of polyethylene glycol and benzoic acid, number average molecular weight 400, hydroxyl value 5.0), KF-410 (manufactured by Shin-Etsu Chemical Co., Ltd., aralkyl-modified polysiloxane compound), FL-5 (manufactured by Shin-Etsu Chemical Co., Ltd., fluorine-modified silicone), X-22-4015 (manufactured by Shin-Etsu Chemical Co., Ltd., hydroxyl group-containing silicone compound), KF-6011 (manufactured by Shin-Etsu Chemical Co., Ltd., polyether-modified polysiloxane compound), KR-5206 (manufactured by Shin-Etsu Chemical Co., Ltd., alkyd-modified polysiloxane compound), and KR-5234 (manufactured by Shin-Etsu Chemical Co., Ltd., polyester-modified polysiloxane compound).

[0088] The content of the plasticizer (P) in the resin composition is preferably 5 parts by weight or more per 100 parts by weight of the total of the resin (A) and the carbon black (B) from the viewpoint of significantly adjusting the characteristics of the odor sensor, and is preferably 100 parts by weight or less from the viewpoint of film-forming properties during the production of the odor sensor.

[0089] The resin composition may contain a resin other than the resin (A) as long as the effect of the present invention is not impaired. Examples of the resin other than the resin (A) include an acrylic polymer, a vinyl polymer, a polyurethane resin, a polyether polyol, a diene polymer, and a polyester.

[0090] <Method for producing resin composition> The resin composition is obtained as a slurry by mixing the resin (A), carbon black (B), and, if necessary, the solvent (D) and kneading them uniformly with a stirrer. When the solvent (D) is added, the solvent (D) is distilled off from the resin composition. The solvent (D) may be distilled off from the resin composition produced by uniform mixing, or from the coating film produced during the production of the sensor element described below.

[0091] <Main effects> The electrical conductivity of the resin composition described above varies depending on the amount of substance adsorbed to the resin composition. Furthermore, the process of substance adsorption to the resin composition differs for each substance. Therefore, by forming a detection unit capable of adsorbing a substance using the resin composition, the resin composition can be used in a sensor element of a chemiresistor sensor. By using the resin composition, it is possible to improve discrimination performance. For example, it is possible to discriminate real patterns in which multiple substances interact or real patterns caused by substances whose composition is unknown. Furthermore, the resin composition has excellent compositional stability and coating stability. Therefore, the stability of discrimination performance is improved when used in a sensor element.

[0092] The sensor described in Reference 1 is believed to be capable of detecting odors composed of single compounds. However, many odors are mixtures of multiple substances. The sensor described in Reference 1 lacks the ability to distinguish odor components in the detection section, resulting in insufficient odor discrimination performance for mixtures. Reference 2 demonstrates that by utilizing the differences in the chemical structure of the conductive polymers used in the detection section, the detection section can differentiate its response to various compounds via each conductive polymer, enabling the recognition of odor mixtures. However, the chemical structures of conductive polymers are limited, making it difficult to sensitively separate the response of the detection section to any odor component, making it difficult to distinguish between odors composed of similar components. Reference 3 proposes a method using a mixture of organic polymers, plasticizers, and conductive substances as the detection material in the detection section, detecting the penetration of odor components into the organic polymer as a change in the electrical resistance of the mixture. Taking advantage of the fact that different organic polymers with different compositions allow different odor components to penetrate, multiple detection sections made of the above detection material containing organic polymers of different compositions can be arranged in parallel to form an array, enabling the recognition of odor mixtures. However, with the organic polymers and organic polymers containing plasticizers described above, even if multiple combinations of organic polymers and conductive materials are prepared, the difference in chemical properties between the organic polymers is small, so the odor discrimination performance is insufficient. These conventional technologies cannot accurately detect, for example, real odor patterns where multiple substances interact or real odor patterns caused by substances with unknown compositions.

[0093] [2. Sensor element 31] The following describes the outline and effects of a sensor element 31 to which a resin composition according to one embodiment of the present invention is applied. Note that an odor sensor is used as the chemiresistor sensor below.

[0094] The above-mentioned resin composition exhibits different temporal changes in electrical conductivity when odorant A is adsorbed onto the resin composition than when odorant B, which is different from odorant A, is adsorbed onto the resin composition. By utilizing this property, a sensor element 31 capable of detecting and identifying odorants can be realized.

[0095] The sensor element 31 includes an odorant receiving layer 315 containing the resin composition described above, a first metal wiring 313A, and a second metal wiring 313B. In the following, when there is no need to distinguish between the first metal wiring 313A and the second metal wiring 313B, they may be referred to as metal wiring 313.

[0096] In this specification, the term "odorant receiving layer" refers to a layer that adsorbs the odorant to be recognized. The odorant receiving layer is formed from the resin composition described above. The odorant receiving layer can be provided as part of a sensor element according to an embodiment of the present invention.

[0097] Here, the first metal wiring 313A and the second metal wiring 313B will be described with reference to Fig. 2 and Fig. 3. Fig. 2 is a top view showing an example of the configuration of sensor element 31, and Fig. 3 is a cross-sectional view showing an example of the configuration of sensor element 31 shown in Fig. 2.

[0098] The first metal wiring 313A and the second metal wiring 313B are metal wirings that function as electrodes for measuring changes in the electrical conductivity of the odorant receiving layer 315 (i.e., the resin composition). That is, the first metal wiring 313A and the second metal wiring 313B are spaced apart from each other, and the odorant receiving layer 315 is in contact with at least a portion of the first metal wiring and at least a portion of the second metal wiring. In one example, the first metal wiring 313A and the second metal wiring 313B are metal wirings that are not in direct contact with each other, and may be metal wirings that are approximately parallel to each other, as shown in FIG. 2.

[0099] As shown in FIG. 2, metal wiring 313 including first metal wiring 313A and second metal wiring 313B may be disposed on substrate 311. Substrate 311 may be a substrate such as glass epoxy commonly used in electronic circuits. Metal wiring 313 may be metal wiring such as copper or gold. When viewed perpendicular to the surface of the substrate, the thickness of each of first metal wiring 313A and second metal wiring 313B is preferably 10 μm to 2 mm, more preferably 10 μm to 1 mm. When viewed parallel to the surface of the substrate, the height, i.e., thickness, of each of first metal wiring 313A and second metal wiring 313B is preferably 1 μm to 100 μm, more preferably 10 μm to 50 μm. The spacing between first metal wiring 313A and second metal wiring 313B is preferably 1 μm to 1 mm, more preferably 1 μm to 100 μm. The length of the metal wiring 313 is preferably 10 μm to 50 mm, and more preferably 10 μm to 30 mm.

[0100] The metal wiring 313 may be disposed on a seal substrate 312. Figure 3 shows the AA cross section of Figure 2. As shown in Figure 3, the seal substrate 312 may be disposed on a substrate 311 such as glass epoxy, and the metal wiring 313 may be disposed on the seal substrate 312. Vinyl tape 314 may be used to secure the seal substrate 312 to the substrate 311. The vinyl tape 314 may also be used to adjust the length of the exposed portion of the metal wiring 313 by masking the excess portion of the metal wiring 313. Here, the exposed portion of the metal wiring 313 is the portion where the metal wiring 313 contacts the odorant receiving layer 315. The vinyl tape 314 may also be an insulator for adjusting the length of the portion where the metal wiring 313 contacts the odorant receiving layer 315.

[0101] The odorant receiving layer 315 may be in contact with at least a portion of the first metal wiring 313A and at least a portion of the second metal wiring 313B. The odorant receiving layer 315 may be arranged to fill the area between the first metal wiring 313A and the second metal wiring 313B, as shown in Figures 2 and 3, for example.

[0102] If the electrical conductivity of the odorant receiving layer 315 (i.e., the electrical conductivity of the sensor element 31) is low, it is desirable that the distance between the first metal wiring 313A and the second metal wiring 313B be a predetermined distance (for example, 500 μm) or less.

[0103] The sensor element 31 is capable of detecting and distinguishing various odorous substances by applying a resin composition whose electrical conductivity changes differently over time when odorous substance A is adsorbed and when odorous substance B, which is different from odorous substance A, is adsorbed.

[0104] As shown in Figure 4, by replacing metal wiring 313A and 313B with piezoelectric elements 313E and 313F and electrically connecting 313E and 313F with metal wiring 313G, it can also be used as a membrane surface stress sensor (MSS), a different type of sensor element. A membrane surface stress sensor can detect the generation of stress due to odorant adsorption as a change in the electrical conductivity of the piezoelectric element over time, even if the odorant receiving layer does not have electrical conductivity, and can detect and distinguish various odorants. When a resin composition is used in a membrane surface stress sensor, the filler in the resin composition is used to increase the Young's modulus of the odorant receiving layer and improve sensitivity. Therefore, electrical conductivity is not essential for the filler, and insulating fillers can be used.

[0105] <Method of manufacturing sensor element> The sensor element 31 can be manufactured by preparing the odorant receiving layer 315 using the resin composition according to the embodiment of the present invention described above. The odorant receiving layer 315 can be prepared by applying the resin composition as a coating liquid and solidifying or curing the resulting coating. The resin composition can be applied using known coating techniques.

[0106] In addition, if the polymerization reaction of resin (A) can be carried out in a coating film, the odorant receiving layer 315 may be produced by applying a composition containing a monomer of resin (A) to the seal substrate 312 instead of the resin composition, and polymerizing the monomer in the resulting coating film. Examples of such monomers include radically polymerizable monomers, and examples of resin (A) synthesized by such monomers include acrylic polymers. The composition containing the monomer may further contain additives used in the polymerization of the monomer to the extent that the effects of the present invention can be obtained. Examples of such polymerization additives include polymerization initiators for radical polymerization.

[0107] [3. Odor Sensor 30] Below, the outline and effects of an odor sensor 30 employing sensor element 31 will be described with reference to Fig. 1. Fig. 1 is a schematic diagram showing an example of the configuration of an odor measuring device 100 equipped with an odor sensor 30 employing sensor element 31. Note that in the sensor element 31 shown in Fig. 1, vinyl tape 314 is omitted for simplification.

[0108] The odor sensor 30 includes a sensor element 31 that detects odor substances, a constant current source 32 (power supply), and a voltmeter 33 (measuring device).

[0109] The first metal wiring 313A and the second metal wiring 313B of the sensor element 31 are connected by a lead wire W. Fig. 1 shows an example in which a constant current source 32 and a voltmeter 33 are arranged on the lead wire W.

[0110] The constant current source 32 is a power source for supplying power to the sensor element 31. The constant current source 32 supplies a constant current (for example, a direct current of 1 mA) to the sensor element 31 via a lead wire.

[0111] The voltmeter 33 measures the potential difference that occurs between the first metal wiring 313A and the second metal wiring 313B when a constant current supplied from the constant current source 32 is supplied to the odorant receiving layer 315.

[0112] Although not an essential component, the odor sensor 30 may further include a housing 34. The housing 34 is a container capable of containing air containing odorous substances. When the housing 34 is included, the sensor element 31 is placed inside the housing 34.

[0113] The housing 34 has an inlet 341 for introducing an odorant and an outlet 342 for discharging air containing the odorant. The odorant may be introduced by inserting filter paper P or the like soaked in the odorant into the housing 34 through the inlet 341, or by inserting air containing the odorant into the housing 34 through the inlet 341. The housing 34 is a container for containing air containing the odorant at a predetermined concentration (e.g., 200 ppm) or more.

[0114] Although not essential, an airflow generating fan 35 may be provided at the exhaust port 342 of the housing 34. The airflow generating fan 35 is used to generate an airflow inside the housing 34 and to exhaust gas inside the housing 34 from the exhaust port 342 to the outside of the housing 34.

[0115] The odor sensor 30 may include a constant voltage source (power supply) (not shown) instead of the constant current source 32, and an ammeter (measuring device) (not shown) instead of the voltmeter 33. In this case, the constant voltage source functions as a power source for supplying power to the sensor element 31, and applies a constant voltage to the sensor element 31 via lead wires. Meanwhile, the ammeter measures the value of the current flowing between the first metal wiring 313A and the second metal wiring 313B when a constant voltage is applied to the odorant receiving layer 315.

[0116] The odor sensor 30 outputs a measurement value that indicates the change over time in the electrical conductivity of the sensor element 31 before and after an odorant is adsorbed to the sensor element 31. This makes it possible to detect and distinguish various odorants.

[0117] 4. Odor Measuring Device 100 The odor sensor 30 described above can output the change in the electrical conductivity of the sensor element 31 over time for each odor substance when various odor substances are adsorbed to the sensor element 31. By applying this odor sensor 30, it is possible to compare the change in the electrical conductivity of the sensor element 31 over time when odor substance A is adsorbed to the sensor element 31 with the change in the electrical conductivity of the sensor element 31 over time when odor substance B is adsorbed to the sensor element 31. Based on the results of such comparison, an odor measuring device 100 can be realized that can estimate the odor substance adsorbed to the sensor element 31.

[0118] Furthermore, the odor measuring device 100 can estimate odor substances with high accuracy by using an estimation model 22 generated by machine learning. The estimation model 22 can be generated using training data that includes a combination of measurement values ​​measured when each of a plurality of odor substances is adsorbed onto at least one sensor element 31 and identification information specific to the odor substance that provided the measurement value.

[0119] The following describes the outline and effects of an odor measuring device 100 that uses the odor sensor 30. The odor measuring device 100 is a device that estimates odor substances adsorbed to a sensor element 31 based on changes in electrical conductivity that occur in the sensor element 31 to which the above-mentioned resin composition is applied.

[0120] First, the configuration of an odor measurement device 100 according to one embodiment of the present invention will be described with reference to Fig. 1. Fig. 1 is a block diagram showing an example of the configuration of the odor measurement device 100.

[0121] As shown in FIG. 1, the odor measurement device 100 includes an estimation device 10 and an odor sensor 30.

[0122] <Estimation device 10> The estimation device 10 is a device that estimates odor substances detected by an odor sensor 30. The estimation device 10 is, for example, a computer, and includes a CPU and memory (not shown). The estimation device 10 is communicatively connected to the odor sensor 30. Specifically, the estimation device 10 estimates odor substances by analyzing measurement values ​​acquired from the odor sensor 30. The configuration of the estimation device 10 will be described later.

[0123] (Generation of estimated model 22) Next, the configuration of the odor measurement device 100 that performs the process of generating the estimation model 22 used to estimate odor substances, and the process of generating the estimation model 22 will be described with reference to FIGS. 5 and 6. FIG.

[0124] The estimation model 22 is generated by machine learning using training data that includes a combination of measurement values ​​measured by the voltmeter 33 when each of a plurality of odor substances is adsorbed onto at least one sensor element, and identification information specific to the odor substance that provided the measurement value. Here, the identification information specific to the odor substance may be, for example, the name, CAS number, and chemical formula of the odor substance.

[0125] (Configuration of the estimation device 10 (generation of the estimation model 22)) Fig. 5 is a functional block diagram showing an example of the configuration of the odor measuring device 100. For ease of explanation, the same reference numerals are used to denote components having the same functions as those described in Fig. 1, and their description will not be repeated.

[0126] As shown in FIG. 5, the estimation device 10 includes an input unit 15, a control unit 1, and a storage unit 2.

[0127] The input unit 15 is for receiving various input operations from the user, and may be, for example, a keyboard, a mouse, a touch panel, or the like.

[0128] The control unit 1 includes a measurement value acquisition unit 11 (acquisition unit), a change pattern analysis unit 12 (analysis unit), a learning control unit 13, and an estimation model generation unit .

[0129] The measurement value acquiring unit 11 acquires a measurement value from the voltmeter 33. Furthermore, the measurement value acquiring unit 11 uses the acquired measurement value to calculate a value indicating the electrical conductivity of the sensor element 31 (for example, a resistance value, an impedance, etc.). The measurement value acquiring unit 11 may acquire the measurement value from the voltmeter 33 at predetermined time intervals (for example, every 0.1 seconds).

[0130] The change pattern analysis unit 12 analyzes the change over time in the electrical conductivity of at least one sensor element 31. Using the resistance value calculated by the measurement value acquisition unit 11, the change pattern analysis unit 12 calculates a value indicating the amount of change in the electrical conductivity of the sensor element 31 due to the adsorption of an odorant. The change pattern analysis unit 12 generates data indicating a change pattern that indicates the change over time in the calculated amount of change in electrical conductivity. If the generated change pattern is for a known odorant, the change pattern analysis unit 12 may associate the generated change pattern with identification information specific to the known odorant and store it in the change pattern database 21 (learning data).

[0131] The learning control unit 13 reads the change pattern database 21 from the storage unit 2 and controls the generation of the estimation model 22 by machine learning. Here, the change pattern database 21 is a database containing combinations of measurement values ​​measured when multiple odor substances are adsorbed onto the sensor element 31 and identification information unique to the known odor substances that provided the measurement values. The learning control unit 13 inputs the change patterns read from the change pattern database 21 to the estimation model generation unit 14. In addition, the learning control unit 13 compares the identification information of the odor substances corresponding to the change pattern input to the estimation model generation unit 14 with the estimation results output from the estimation model generation unit 14, and outputs correction instructions to the estimation model generation unit 14 according to the comparison results.

[0132] The estimation model generation unit 14 generates the estimation model 22 by a machine learning algorithm using the change patterns stored in the change pattern database 21. The estimation model generation unit 14 may be configured to generate the estimation model 22 by using a known supervised machine learning algorithm. Examples of machine learning algorithms that can be applied to the estimation model generation unit 14 include the k-nearest neighbor method, logistic regression, support vector machines, random forests, and neural networks.

[0133] (Process for generating estimation model 22) Specific processes performed by each unit of the control unit 1 will be described below with reference to Fig. 6. Fig. 6 is a flowchart showing an example of the flow of processes performed by the estimation device 10 to generate the estimation model 22.

[0134] First, the measurement value acquiring unit 11 acquires the voltage value V0 measured by the odor sensor 30 before the filter paper P soaked in the odor substance is inserted into the housing 34, and calculates the resistance value R0 (Step S11). The resistance value R0 is preferably 200 to 1000 Ω, more preferably 250 to 900 Ω, and most preferably 300 to 800 Ω.

[0135] Meanwhile, the input unit 15 receives input such as the name of a known odor substance that has been soaked in the filter paper P inserted into the housing 34 (step S12). The process of step S12 may be performed before step S11.

[0136] Next, the measurement value acquiring unit 11 acquires the voltage value V measured by the odor sensor 30 immediately after the filter paper P soaked with the known odor substance is inserted into the housing 34, and calculates the resistance value R.

[0137] (Step S13) Next, the change pattern analysis unit 12 calculates R / R0 using the resistance values ​​R0 and R (step S14). R / R0 is a value indicating the amount of change in the electrical conductivity of the sensor element 31 due to the adsorption of a known odorant. The change pattern analysis unit 12 may calculate R-R0 instead of R / R0. The change pattern analysis unit 12 stores the change pattern of R / R0 over time in the change pattern database 21 in association with the name of the input known odorant (step S15).

[0138] If no change patterns are stored for the predetermined types of existing odor substances (NO in step S16), that is, if there is still insufficient data to use for machine learning, the process returns to step S11.

[0139] If a change pattern is stored for a predetermined type of existing odor substance (YES in step S16), the learning control unit 13 reads out the change pattern for the known odor substance stored in the change pattern database 21 and inputs it to the estimation model generation unit 14. The estimation model generation unit 14 generates an estimation model 22 by a machine learning algorithm using the change pattern stored in the change pattern database 21 (step S17).

[0140] The estimation model generation unit 14 stores the estimation model 22 generated by predetermined machine learning in the storage unit 2 (step S18).

[0141] 5 and 6, the estimation device 10 generates the estimation model 22, but this is not limiting. For example, the estimation device 10 may provide the same data as the change pattern database 21 to an external computer different from the estimation device 10 that has the same functions as the learning control unit 13 and the estimation model generation unit 14, and have the computer generate the estimation model 22.

[0142] (Estimation of odor substances) Next, the configuration of the odor measurement device 100a that estimates odor substances using the estimation model 22 and the estimation process will be described with reference to FIGS.

[0143] (Configuration of Estimation Device 10a (Execution of Estimation Process)) Fig. 7 is a functional block diagram showing an example of the configuration of the odor measuring device 100a. For ease of explanation, the same reference numerals are used to designate components having the same functions as those described in Fig. 1 and Fig. 5, and their description will not be repeated.

[0144] As shown in Fig. 7, the estimation device 10a includes a control unit 1a, a storage unit 2a, and an output unit 18. Here, Fig. 7 shows a configuration example in which the estimation device 10 shown in Fig. 5 is used for odor substance estimation processing. In other words, the estimation device 10 shown in Fig. 5 and the estimation device 10a shown in Fig. 7 may be computers with the same hardware configuration.

[0145] The output unit 18 is for presenting the estimation result to the user, and may be, for example, a display, a speaker, a lamp, or the like.

[0146] The control unit 1 a includes a measurement value acquisition unit 11 (acquisition unit), a change pattern analysis unit 12 (analysis unit), an estimation unit 16, and an output control unit 17.

[0147] The estimation unit 16 uses the estimation model 22 to estimate the odor substance from the analysis results obtained by analyzing the measurement values ​​acquired from the odor sensor 30.

[0148] The output control unit 17 controls the output unit 18 to output the estimation result.

[0149] (Estimation process) Specific processes performed by each unit of the control unit 1a will be explained below with reference to Fig. 8. Fig. 8 is a flowchart showing an example of the process flow for the estimation device 10a to estimate an odor substance.

[0150] First, the measurement value acquiring unit 11 acquires the voltage value V0 measured by the odor sensor 30 before the filter paper P soaked in the odor substance is inserted into the housing 34, and calculates the resistance value R0 (step S1).

[0151] Next, the measurement value acquisition unit 11 acquires the voltage value V measured by the odor sensor 30 immediately after inserting the filter paper P soaked in the unknown (i.e., the odor substance to be estimated) into the housing 34, and calculates the resistance value R (step S2).

[0152] Next, the change pattern analysis unit 12 calculates R / R0 using the resistance value R0 and the resistance value R (step S3).

[0153] Next, the estimation unit 16 estimates the unknown odor substance from the pattern of change in R / R0 over time based on the estimation model 22 (step S4).

[0154] The output control unit 17 controls the output unit to output the estimation result (step S5).

[0155] [Embodiment 2] In the above embodiment, the odor sensor 30 has been described as having one sensor element 31, but the odor sensor 30 may also have two or more sensor elements 31. For example, the odor sensor 30b may have sensor elements 31 and 31b in which the resin compositions used in the odorant receiving layer 315 are different from each other. This will be explained using FIG. 9. FIG. 9 is a block diagram showing an example of the configuration of an odor measuring device 100b according to another embodiment of the present invention. For ease of explanation, components having the same functions as those described in FIG. 1 are denoted by the same reference numerals, and their explanations will not be repeated.

[0156] 9 includes odor sensors 30 and 30b and an estimation device 10b. The odor sensor 30b includes a sensor element 31 and a sensor element 31b, and the resin composition used in the odorant receiving layer 315 of the sensor element 31 and the odorant receiving layer 315b of the sensor element 31b may be different.

[0157] The estimation device 10b may be a computer having the same configuration as the estimation devices 10 and 10a. The estimation device 10b acquires and analyzes a first measurement value measured by a voltmeter 33 when a constant current is supplied from a constant current source 32 to the sensor element 31, and a second measurement value measured by a voltmeter 33b when a constant current is supplied from a constant current source 32b to the sensor element 31b.

[0158] By providing multiple sensor elements in which resin compositions with different odorant adsorption properties are used in the odorant receiving layer, the odor measuring device 100b can simultaneously perform estimations for multiple odorants.

[0159] Furthermore, by using the odor measurement device 100b, it is possible to obtain, for each known odor substance, a first change pattern indicating a change in the electrical conductivity of the sensor element 31 and a second change pattern indicating a change in the electrical conductivity of the sensor element 31b. The estimation model 22 may be generated by machine learning using both the first change pattern and the second change pattern. The odor measurement device 100b estimates odor substances using the estimation model 22 generated in this way, and therefore can more precisely identify each odor substance.

[0160] [Embodiment 3] Hereinafter, one embodiment of the present invention will be described in detail.

[0161] The odor measurement device 100b of the second embodiment is configured such that a filter paper P soaked in an odorant is introduced into a housing 34 containing two sensor elements (i.e., sensor elements 31 and 31b). With this configuration, it is not possible to control the timing at which the odorant reaches the sensor elements 31 and 31b, or to adjust the concentration of the odorant. Therefore, the odor measurement device 100c of the present embodiment is separately equipped with a sensor chamber 60 containing multiple sensor elements (hereinafter, sensor element group 31A), and a target sample receiving section 50 into which a target sample containing an odorant is introduced and into which gas containing the odorant generated from the target sample is enclosed. In this embodiment, the individual sensor elements included in the sensor element group 31A will be referred to simply as "sensor element."

[0162] The odor measurement device 100c of this embodiment employs a configuration in which the gas containing the odor substance inside the target sample receiving section 50 is pushed toward the sensor chamber 60 using another gas (carrier gas). In this embodiment, the gas inside the target sample receiving section 50 when the target sample is introduced into the target sample receiving section 50 (i.e., the gas containing the odor substance to be detected) is referred to as the first gas. On the other hand, the carrier gas used to push the first gas toward the sensor chamber 60 is referred to as the second gas.

[0163] 10 is a schematic diagram of an odor measurement device 100c. As shown in FIG. 10, the odor measurement device 100c includes a target sample receiving unit 50, a sensor chamber 60, a gas supply unit 80, and an estimation device 10b. The odor measurement device 100c may further include a regulator 51.

[0164] 10 shows an example in which gas flows from gas supply unit 80 to target sample receiving unit 50 and sensor chamber 60 in that order. Gas supply unit 80, target sample receiving unit 50, and sensor chamber 60 are each connected by a tube.

[0165] The target sample receiving section 50 is capable of receiving a target sample containing an odorant therein and retaining a first gas. The target sample receiving section 50 has a first port 501 through which a second gas entering the inside passes, and a second port 502 through which the first gas and the second gas exiting the inside can pass. The target sample receiving section 50 may also have a sample introduction port 503, which will be described later.

[0166] 10 shows an embodiment in which the first port 501 is located at the top of the target sample receiving section 50 and the second port 502 is located at the bottom of the target sample receiving section 50, but this is not limiting. For example, the positions of the first port 501 and the second port 502 can be set appropriately depending on the types and combinations of odor components contained in the first gas. For example, the positions of the first port 501 and the second port 502 may be changed depending on whether the weight per unit volume of the odor components contained in the first gas (i.e., specific gravity) is heavier or lighter than that of the second gas. Furthermore, the target sample receiving section 50 may be internally provided with an airflow generating fan 35, as in FIG. 9.

[0167] The target sample receiving unit 50 has a sample inlet 503 for receiving a liquid or solid target sample. Similar to FIG. 9, FIG. 10 shows an embodiment in which filter paper P soaked in an odorant is introduced as the target sample. The target sample receiving unit 50 may also have a mounting unit (not shown) for mounting the target sample. If the target sample is a liquid, the mounting unit may be a cup for holding the liquid. If the target sample is a solid, the mounting unit may be a Petri dish on which the solid is placed. The target sample may be introduced into the target sample receiving unit 50 in a gaseous state as a first gas through the sample inlet 503. In this way, since the target sample receiving unit 50 can receive a liquid or solid target sample, it is possible to adjust the concentration of the odorant in the first gas. For example, even if the same odorant is used, it is easy to adjust the concentration of the odorant in the first gas.

[0168] The inner surface of the target sample receiving section 50 may be lined with a material that is inactive to odorants. A material that is inactive to odorants is a material that does not significantly change the concentration of each odorant contained in the gas sent to the sensor chamber 60. For example, a material that is inactive to odorants is a material that odorants are unlikely to adsorb or dissolve into. Examples of materials that are inactive to odorants include glass, metal, and resin. When using metal, stainless steel (SUS) is preferred, and when using resin, fluorine-based resin, polypropylene (PP), polyethylene (PE), ABS resin, and polyethylene terephthalate (PET) are preferred.

[0169] If the inner surface of the target sample receiving portion 50 is made of a material that adsorbs the odorous substances contained in the first gas, the odorous substances may be adsorbed to each portion, which may affect subsequent measurements.

[0170] Since the inner surface of the target sample receiving portion 50 is made of a material that is inactive to odorants, the risk of the material of the inner surface reacting with the odorants contained in the first gas, or the odorants being adsorbed onto the inner surface, is reduced. Therefore, the risk of the odorants contained in the first gas supplied to the sensor chamber 60 changing while contained in the target sample receiving portion 50, or the concentration of the odorants being diluted, is reduced.

[0171] Whether the target sample is a liquid or a solid, the odor measurement device 100c is provided with the target sample receiving section 50, thereby making the concentration of the first gas uniform within the target sample receiving section 50 before sending the first gas into the sensor chamber 60. Furthermore, by providing the target sample receiving section 50, the odor measurement device 100c can push the first gas into the sensor chamber 60 at a constant flow rate. This allows the odor measurement device 100c to send the first gas to the sensor chamber 60 under the same conditions each time, even when measurements are repeated, thereby enabling repeated, stable measurements.

[0172] The volume of the target sample receiving section 50 is preferably between 1 and 100 times the volume of the sensor chamber 60. In particular, the volume of the target sample receiving section 50 is preferably larger than the volume of the sensor chamber 60. The volume of the target sample receiving section 50 is more preferably between 2 and 80 times the volume of the sensor chamber 60, and even more preferably between 4 and 60 times the volume of the sensor chamber 60. By making the volume of the target sample receiving section 50 at least 1 time larger than the volume of the sensor chamber 60, the concentration of odor substances in the sensor chamber 60 is appropriately adjusted, and measurement results from the sensor provided in the sensor chamber 60 are stably output. Furthermore, by making the volume of the target sample receiving section 50 less than 100 times the volume of the sensor chamber 60, measurement results from the sensor are stably output, and the odor measurement device 100c can be kept compact.

[0173] If the volume of the target sample receiving section 50 is less than one time the volume of the sensor chamber 60, the odor substances generated in the target sample receiving section 50 may be diluted in the sensor chamber 60, which may reduce the measurement sensitivity of the sensor. Also, if the volume of the target sample receiving section 50 is more than 100 times the volume of the sensor chamber 60, the volume of the target sample receiving section 50 may be too large, which may increase the overall size of the odor measuring device 100c.

[0174] FIG. 10 shows an example in which the volume of the target sample receiving portion 50 is eight times the volume of the sensor chamber 60 .

[0175] For example, if the inner surface of the tubular body 93 is made of a material that adsorbs odorous substances contained in the first gas, the odorous substances may be adsorbed to various parts, potentially affecting subsequent measurements. Therefore, it is preferable that the inner surface of the tubular body 93, which guides the first gas from the target sample receiving section 50 to the sensor chamber 60, be made of a material that is inactive to odorous substances, similar to the inner surface of the target sample receiving section 50. Examples of materials that are inactive to the first gas include glass, metal, and resin. When using metal, stainless steel (SUS) is preferred, and when using resin, fluorine-based resin, polypropylene (PP), polyethylene (PE), ABS resin, and polyethylene terephthalate (PET) are preferred.

[0176] The target sample receiving section 50 may be configured to be detachable from the tubular bodies 92 and 93. In this way, since the target sample receiving section 50 is detachable, when the previous measurement is completed and the next measurement is to be performed, a new target sample receiving section 50 can be attached without purging the inside of the target sample receiving section 50. This allows the odor measuring device 100c to perform multiple measurements in a short period of time.

[0177] Furthermore, because the target sample receiving section 50 is detachable, the target sample receiving section 50 into which the target sample has been introduced can be maintained at a desired temperature using a temperature-retaining chamber separate from the odor measurement device 100c. This allows the odor measurement device 100c to adjust the temperature of the target sample receiving section 50, even if, for example, the adjustment section 51 described below cannot be provided in the odor measurement device 100c.

[0178] The adjustment unit 51 adjusts at least one of the temperature and humidity of the first gas contained in the target sample receiving unit 50. When the adjustment unit 51 adjusts the temperature, the adjustment unit 51 is, for example, a heater or a cooler. In this case, the adjustment unit 51 may be configured to cover the entire target sample receiving unit 50. When the adjustment unit 51 adjusts the humidity, the adjustment unit 51 is, for example, a humidifier or a dehumidifier. The adjustment unit 51 may adjust at least one of the temperature and humidity for each type of first gas, or may change at least one of the temperature and humidity at predetermined time intervals during measurement of the same first gas.

[0179] The adjustment unit 51 adjusts at least one of the temperature and humidity of the first gas in the target sample receiving unit 50, so that the odor measuring device 100c can send the first gas to the sensor chamber 60 using conditions according to, for example, the type of the first gas (such as the weight or volatility of the gas). This also allows the odor measuring device 100c to send the first gas at a stable concentration to the sensor chamber 60, improving the accuracy of the measurement.

[0180] The gas supply unit 80 is connected to the first port 501 of the target sample receiving unit 50, and by sending a second gas into the inside of the target sample receiving unit 50, the first gas is sent from inside the target sample receiving unit 50 toward the sensor chamber 60.

[0181] A valve 81 may be provided between the gas supply unit 80 and the target sample receiving unit 50. By opening and closing the valve 81, the start and stop of gas supply from the gas supply unit 80 may be adjusted.

[0182] In this way, the gas supply unit 80 pushes the gas from the first port 501 side of the target sample receiving unit 50 to send the first gas into the sensor chamber 60, so the pressure inside the sensor chamber 60 is positive. This allows the odor measurement device 100c to obtain stable measurement results. Furthermore, because the second gas can be sent by opening and closing the valve 81, the odor measurement device 100c can send the first gas from the target sample receiving unit 50 toward the sensor chamber 60 at any timing. This allows the odor measurement device 100c to improve the reproducibility of the waveform shape output by each sensor element when repeatedly measuring odor substances contained in the first gas using the sensor element group 31A.

[0183] The second gas may be an inert gas or air. Examples of inert gases include argon and nitrogen. When the second gas is an inert gas, the gas supply unit 80 may be a gas cylinder.

[0184] Furthermore, when the second gas is air, the gas supply unit 80 may be a pump. In this case, in order to remove components that react with the first gas contained in the target sample receiving unit 50, the odor measuring device 100c may be provided with, for example, an activated carbon filter on the first port 501 side of the target sample receiving unit 50.

[0185] The odor measuring device 100c may further include a mass flow controller on the side of the first port 501 of the target sample receiving section 50, more specifically, between the valve 81 and the gas supply section 80. The odor measuring device 100c employing this configuration can send the first gas from the target sample receiving section 50 to the sensor chamber 60 at a constant flow rate, allowing the sensor elements of the sensor element group 31A to produce stable outputs.

[0186] The estimation device 10b has the same functions as the estimation device 10b of embodiment 2. If the sensor chamber 60 further includes a sensor element 31c whose substance receiving layer 315 uses a resin composition different from that of the sensor element 31 and the sensor element 31b, the estimation device 10b may further acquire and analyze measurements taken by a voltmeter by supplying a constant current to the sensor element 31c. The estimation device 10b may also display the measurement values ​​themselves, waveforms plotting the measurement values, and estimation results for unknown odor substances based on an estimation model. The estimation device 10b may also display numerical values ​​and graphs showing changes in the abundance ratio of each odor substance in a gas containing multiple odor substances.

[0187] The sensor chamber 60 is a space that houses the sensor element group 31A for measuring odor substances. The sensor chamber 60 is connected to the second port 502 of the target sample receiving section 50. Specifically, the sensor chamber 60 includes a gas supply port 601 and a gas exhaust port 602, and the second port 502 of the target sample receiving section 50 is connected to the gas supply port 601.

[0188] The sensor chamber 60 has multiple passages in which multiple sensor elements capable of outputting measurement results according to the odor substances contained in the gas are arranged. This reduces the time required from when gas begins to be sent into the sensor chamber until all of the multiple sensor elements stably output measurement results. Furthermore, by finely dividing the multiple sensor elements by multiple passages, the variation in airflow turbulence between measurements is reduced, improving measurement accuracy.

[0189] Fig. 11 is a top view showing an example of the configuration of sensor chamber 60. Fig. 11 shows sensor chamber 60 having four passages (i.e., passage 61, passage 62, passage 63, and passage 64). The first gas can be supplied from target sample receiving portion 50 to each of passages 61 to 64.

[0190] Each of the multiple passages (passages 61-64) may be provided with multiple sensor elements that output different measurement results for each odorant. The multiple sensor elements that output different measurement results for each odorant may each have a different resin composition as a substance-receiving layer. That is, the multiple sensor elements arranged in one passage may have different sensitivities and detection specificities to odorants. The sensor chamber 60 in FIG. 11 includes, as an example, the sensor element 31 and the sensor element 31b described in embodiment 2 (FIG. 9) in the passage 61, but is not limited to this. For example, the sensor element 31 and the sensor element 31b may be capable of outputting measurement results corresponding to the same odorant contained in the first gas, but the measurement results output by each sensor element may be different. Furthermore, the sensor element 31 and the sensor element 31b may be capable of outputting measurement results corresponding to different odorants. The measurement results corresponding to an odorant may be, for example, measurement results corresponding to the concentration of the odorant. By arranging multiple sensor elements in each of the multiple passages, each of which outputs a different measurement result for each odor substance, odor measurement device 100c can detect odor substances passing through a single passage using sensor elements with different sensitivities and detection specificities. This allows odor measurement device 100c to comprehensively detect odor substances from multiple different measurement results.

[0191] 11, similar to passage 61, passage 62 is provided with a plurality of sensor elements (such as sensor elements 31c and 31d) capable of outputting measurement results corresponding to the odor substances contained in the first gas. Passage 63 is provided with a plurality of sensor elements (such as sensor elements 31e and 31f) capable of outputting measurement results corresponding to the odor substances contained in the first gas. Passage 64 is provided with a plurality of sensor elements (such as sensor elements 31g and 31h) capable of outputting measurement results corresponding to the odor substances contained in the first gas. These sensor elements may have different resin compositions used in substance receiving layers 315.

[0192] Some of the sensor elements 31 to 31h may be sensor elements having the same detection specificity for odor components. That is, for example, when the sensor element group 31A arranged in the sensor chamber 60 includes n sensor elements, m types of sensor elements (m < n) may be arranged. Also, some of the plurality of sensor elements arranged in the same passage may have the same detection specificity for odor components.

[0193] Further, the sensor chamber 60 has passages 61 to 64, and a plurality of sensor elements may be arranged in each of the passages 61 to 64. In this case, the plurality of sensor elements arranged in each of the passages 61 to 64 constitute the sensor element group 31A. For example, 4 sensor elements may be arranged in the passage 61 and 10 sensor elements may be arranged in the passage 62.

[0194] When different numbers of sensor elements are arranged in each of the passages 61 to 64, the difference in the number of sensor elements arranged in each of the passages 61 to 64 is preferably 10 or less. By the difference in the number of sensor elements arranged in each passage being 10 or less, it is possible to reduce the variation in the timing at which the odor substance is detected by the sensor elements, which may occur due to the passages. Also, since the difference in the number of sensor elements arranged in each of the passages 61 to 64 is 10 or less, the odor measuring device 100c can perform odor measurement in a short time.

[0195] Each of the passages is connected to a pipe body 93 for supplying the first gas into the internal space of the sensor chamber 60. As shown in FIG. 11, the passages 61, 62, 63, and 64 are all connected to one pipe body 93.

[0196] Furthermore, the cross-sectional area of ​​each passage perpendicular to the supply direction in which the first gas is supplied from the pipe 93 may be smaller than the cross-sectional area perpendicular to the axial direction of the pipe 93. This allows the first gas supplied from the target sample receiving section 50 to pass through each passage at a faster flow rate than when passing through the pipe 93. This minimizes the time lag in measurement between the sensor element located closer to the gas supply port 601 and the sensor element located closer to the gas discharge port 602, allowing the odor measuring device 100c to perform highly accurate measurements.

[0197] Furthermore, it is preferable that the gas in the internal space of each passage be replaced within one second after the supply of the first gas begins. The supply of the first gas begins when the first gas is supplied to the gas supply port 601. Furthermore, replacement of the gas in the internal space indicates that the first gas supplied from the gas supply port 601 has reached the gas discharge port 602. In this way, by replacing the gas in the internal space of each passage within one second after the supply of the first gas and the second gas begins, the difference in timing at which the first gas comes into contact with each sensor element is reduced, and the odor measuring device 100c can perform stable measurements. Furthermore, by replacing the gas in the internal space of each passage within one second after the supply of the first gas and the second gas begins, the odor measuring device 100c can perform odor measurements in a short time.

[0198] The flow rate of the first gas passing through each internal space of the passage is preferably 0.1 cm / sec or more and 100 cm / sec or less. Furthermore, the flow rate of the first gas passing through each internal space of the passage is more preferably 1 cm / sec or more and 50 cm / sec or less. The flow rate of the first gas passing through each internal space of the passage may be adjusted, for example, by the degree of pressurization of the gas supply unit 80 described below, or by a mass flow controller described below.

[0199] If the flow rate of the first gas passing through each internal space of the passage is slow, there will be a large difference in the timing at which the first gas comes into contact with all the sensor elements of the sensor element group 31A. On the other hand, if the flow rate of the first gas passing through each internal space of the passage is too fast, the sensor elements of the sensor element group 31A will vibrate due to the influence of the airflow, and the odor measurement device 100c will not be able to perform stable odor measurement. Furthermore, if the flow rate of the first gas passing through each internal space of the passage is too fast, the adsorption of odor substances contained in the first gas to the sensor elements of the sensor element group 31A will be hindered, and the odor measurement device 100c will not be able to perform accurate odor measurement. Furthermore, if the flow rate of the first gas passing through each internal space of the passage is too fast, there is a risk that the first gas in the target sample receiving portion 50 will be consumed before the odor measurement device 100c can perform stable measurement.

[0200] In this way, the flow velocity of the first gas passing through the internal space of each passage is not less than 0.1 cm / sec and not more than 100 cm / sec, so that the odor measuring device 100c can stably measure odors.

[0201] The passages may be arranged in parallel. In Fig. 11, passages 61 to 64 are arranged in parallel with one another. By arranging the passages in parallel in this way, the odor measuring device 100c can ensure space for arranging the passages, and the size of the entire device can be made compact.

[0202] Fig. 12 is a cross-sectional view schematically showing a cross section taken along line BB in Fig. 11. Passage 61 in Fig. 12 is composed of a side wall 610, a side wall 611 opposite side wall 610, a ceiling 621, and a base plate 630 which is the bottom surface.

[0203] 12 shows sensor chamber 60 in which passage 61 has a rectangular cross section, but there are no particular limitations on the cross section of passage 61. For example, the cross section of passage 61 may have an arc shape or a triangle shape.

[0204] The passage 61 and the passage 62 are completely separated by a side wall 611 and a side wall 612, and a configuration may be adopted in which gas cannot pass between the passage 61 and the passage 62.

[0205] 12, as an example, there is a configuration in which two side walls (side wall 611 and side wall 612) are provided between the passage 61 and the passage 62, but this is not limiting. For example, the passage 61 and the passage 62 may be separated by a single side wall.

[0206] 12 is formed as a single unit, the present invention is not limited to this configuration. The entire sensor chamber 60 may be formed as a single unit, or each of the multiple passages may be formed as a separate body.

[0207] 12 includes the sensor element 31 on the substrate 630, which is the bottom surface of the passage 61, but the placement of the sensor element 31 is not limited to this. The sensor element 31 may be placed, for example, taking into consideration the type of target odorant that the sensor element 31 can specifically detect. For example, the sensor element 31 may be placed on any of the side wall 610, the side wall 611, and the ceiling 621. Specifically, if the odorant is lighter than air, the sensor element 31 may be placed on the ceiling 621. By placing the sensor element 31 in a location appropriate for the type of odorant, the odor measuring device 100c can perform highly accurate measurements.

[0208] In FIG. 12, the sensor chamber 60 includes each sensor element on a substrate 630, but may further include a connector between the substrate 630 and each sensor element to connect the substrate 630 and the sensor element.

[0209] Each sensor element may be independently connected to the substrate 630. For example, one embodiment is where each sensor element is connected to the substrate 630 via a connector (e.g., an IC pin). In this way, even if a malfunction occurs in only one sensor element included in the sensor chamber 60, the user can replace only the malfunctioning sensor element.

[0210] Furthermore, when detecting odor substances using multiple types of sensor elements, the optimal combination and placement of the sensor elements to be used will vary depending on the type of odor substance. Because each sensor element is independently connected to the substrate 630 and each sensor element is detachable, the odor measuring device 100c can easily change the optimal combination and placement of sensor elements depending on the odor substance.

[0211] The sensor elements may be disposed in two or more locations on the substrate 630, the sidewall 610, the sidewall 611, and the ceiling 621. This allows the length of the passage 61 to be shorter than when sensor elements are provided on only one surface, thereby making the odor measuring device 100c more compact. Furthermore, because multiple sensor elements can be provided near the gas supply port 601, the odor measuring device 100c can perform odor measurement in a shorter time than when the sensor elements are arranged side by side facing the gas discharge port 602.

[0212] As an example, the sensor chamber 60 in FIG. 12 has four passages, each with one sensor element disposed in the cross-sectional direction; however, the number of passages and the number of sensor elements in the cross-sectional direction are not limited to this. FIG. 13 shows a cross-sectional view of a sensor chamber 60a. As an example, the sensor chamber 60a has two passages (passage 61a and passage 62a). Furthermore, two sensors (i.e., sensor element 31 and sensor element 31c) are disposed in the cross-sectional direction of passage 61a. Also, in the sensor chamber 60a, as described above, the sensor elements may be disposed not only on the substrate 630 but also in two or more locations, such as the substrate 630, the sidewall 610a, the sidewall 613a, and the ceiling 621a. The arrangement of the sensor elements in passage 62a is similar to that in passage 61a.

[0213] The material of the inner surface of sensor chamber 60 is preferably a material that is inactive to odorants, similar to target sample receiving section 50. Examples of inactive materials include glass, metal, and resin. When metal is used, stainless steel (SUS) is preferable, and when resin is used, fluorine-based resin, polypropylene (PP), polyethylene (PE), ABS resin, and polyethylene terephthalate (PET) are preferable. When the material of the inner surface of sensor chamber 60 is a material that adsorbs odorants contained in the first gas, adsorption of the odorants into the sensor chamber may reduce the amount of change in output from the sensor element in subsequent measurements, potentially preventing accurate measurements by odor measuring device 100c.

[0214] The sensor elements of the sensor element group 31A may include a thin film. As an example, the odorant receiving layer 315 in Figures 2 and 3 is a thin film.

[0215] One possible mode for sending the first gas containing an odorant into the sensor chamber 60 is to install a vacuum pump on the gas outlet 602 side of the sensor chamber 60 and use the vacuum pump to draw the gas into the sensor chamber 60 from the gas supply port 601 side of the sensor chamber 60. However, if the sensor elements 31 and 31b have thin films, negative pressure within the sensor chamber 60 may cause the thin films to expand, preventing the sensor elements 31 and 31b from outputting stable measurement results. In the odor measurement device 100c according to this embodiment, the gas supply unit 80 pushes the gas from the first port 501 side of the sensor chamber 60 and the target sample receiving unit 50 to send the first gas into the sensor chamber 60, so the pressure within the sensor chamber 60 is positive. Therefore, the odor measurement device 100c can obtain stable measurement results even if the sensor elements of the sensor element group 31A have thin films.

[0216] The thin film of the sensor element of the sensor element group 31A may contain a filler, a resin composition, and a surfactant. Specific embodiments of the sensor element will be described later.

[0217] [Sensor element] The odor measuring device 100b of embodiment 2 includes two sensor elements 31, 31b. In embodiment 2, the variation in the shape, area, and thickness of the odorant receiving layers 315, 315b of the sensor elements is not specifically specified, but it is preferable that the shape, area, and thickness of the odorant receiving layers 315, 315b each have little variation. This is because if there is variation in the shape, area, and thickness of the odorant receiving layers of multiple sensor elements, it may be difficult to stably measure odorants. Hereinafter, odorant receiving layers will be collectively referred to as "odorant receiving layers."

[0218] The sensor elements 31 and 31b of the second embodiment each include a first metal wiring 313A and a second metal wiring 313B as electrodes, with the metal wirings arranged parallel to each other (see FIG. 2). The sensor elements 31 and 31b of the second embodiment also include an odorant receiving layer 315 that fills the area between the first metal wiring 313A and the second metal wiring 313B. The sensor element group 31A may include, in addition to the sensor elements 31 and 31b, a sensor element that has a different arrangement of metal wiring (i.e., electrodes) and a different shape of odorant receiving layer than the sensor elements 31 and 31b. Hereinafter, what was referred to as the metal wiring 313 in the first and second embodiments will also be referred to as the electrode 313.

[0219] The sensor element comprises an electrode 313 disposed on a substrate 311 and an odorant receiving layer formed on the electrode 313. The odorant receiving layer is circular or strip-shaped. When the odorant receiving layer is circular, the diameter R of the circle may be 0.2 mm or more and 10 mm or less. When the odorant receiving layer is strip-shaped, the width W of the strip in the short direction may be 0.2 mm or more and 10 mm or less. Here, strip-shaped refers to a surface shape that has a width in the short direction and a length in the long direction. When the odorant receiving layer is circular, the diameter R of the circle is preferably 1.5 mm or more and 2.7 mm or less. When the odorant receiving layer is strip-shaped, the width W of the strip in the short direction is preferably 1.5 mm or more and 2.7 mm or less.

[0220] By setting the diameter R or width W of the circle of the odorant receiving layer of the sensor elements included in the sensor element group 31A within the above range, the odor measuring device 100c can stably perform measurements according to the odorant.

[0221] If the diameter R of the odorant receiving layer is less than 0.2 mm or the width W is less than 0.2 mm, the area that receives the odorant will be small, and the odor measuring device 100c will not be able to perform stable measurements.

[0222] Furthermore, if the diameter R of the odorant receiving layer is greater than 10 mm, or if the width W is greater than 10 mm, the area of ​​each sensor element increases, and the size of the sensor chamber 60 containing the sensor element group 31A also increases. If the size of the sensor chamber 60 increases, it becomes difficult to uniformly diffuse the first gas containing the odorant within the sensor chamber 60, and the odor measuring device 100c is therefore unable to perform stable measurements.

[0223] FIG. 14 is a top view showing an example of the configuration of one sensor element 31c included in the sensor element group 31A. The sensor element 31c comprises electrodes 313 (first electrode 313C, second electrode 313D) arranged on a substrate 311 and a circular odorant receiving layer 315c formed on the electrodes 313. The diameter R of the odorant receiving layer 315c is 0.2 mm or more and 10 mm or less. In FIG. 14, the shape of the odorant receiving layer 315c of the sensor element 31c is elliptical as an example, but is not limited to this. When the shape of the odorant receiving layer 315c is elliptical, the average of the minor axis and the major axis may be 0.2 mm or more and 10 mm or less. The shape of the odorant receiving layer 315c may also be a perfect circle.

[0224] 15 is a top view showing an example of the configuration of one sensor element 31d included in the sensor element group 31A. The sensor element 31d comprises electrodes 313 (first electrode 313C, second electrode 313D) arranged on a substrate 311, and a strip-shaped odorant receiving layer 315d formed on the electrodes 313. The width of the odorant receiving layer 315d in the short direction is 0.2 mm or more and 10 mm or less.

[0225] By having the above configuration, the instability of the measurement result output that can be caused by variations in the shape and area of ​​the odorant receiving layer of each sensor element is reduced, and the odor measuring device 100c can measure odorants with high accuracy.

[0226] The sensor element group 31A may include a plurality of sensor elements other than the sensor elements 31a to 31d. In Fig. 10, the sensor element group 31A is made up of 16 sensor elements as an example, but the number of sensor elements is not limited to this.

[0227] The odorant receiving layers of the multiple sensor elements included in the sensor element group 31A may each contain a filler, a resin composition, and a surfactant.

[0228] The odorant receiving layers of the multiple sensor elements included in the sensor element group 31A may each have a different content ratio of filler, resin composition, and surfactant. If the content ratio of filler, resin composition, and surfactant contained in the odorant receiving layers differs, the sensitivity and detection specificity of the sensor elements to odorants will also differ.

[0229] As described above, the odor measuring device 100c is equipped with multiple sensor elements each having an odorant receiving layer with a different content ratio of filler, resin composition, and surfactant, thereby being able to detect a wide variety of odorants.

[0230] The odorant receiving layer of the sensor element included in the odor measuring device 100c according to this embodiment may have a thickness of 0.1 μm or more and 1000 μm or less. Furthermore, the thickness of each odorant receiving layer may preferably be 1 μm or more and 100 μm or less.

[0231] By having the thickness of the odorant receiving layer of the sensor element within the above range, the instability of the measurement result output that may be caused by variations in the thickness of the odorant receiving layer of each sensor element is reduced, and the odor measuring device 100c can measure odorants with high accuracy.

[0232] If the thickness of the odorant receiving layer is less than 0.1 μm, the value will be close to the particle diameter of the filler dispersed in the odorant receiving layer, so the uniformity of the thickness of the odorant receiving layer cannot be guaranteed, and there is a risk that the odor measuring device 100c will not be able to output stable measurement results.On the other hand, if the thickness of the odorant receiving layer is greater than 1000 μm, the odorant diffusion time within the odorant receiving layer will be longer, making it difficult for the odor measuring device 100c to measure the odorant with high accuracy.

[0233] By having the thickness of the odorant receiving layer of the sensor element within the above range, the instability of the measurement result output that may be caused by variations in the thickness of the odorant receiving layer of each sensor element is reduced, and the odor measuring device 100c can measure odorants with high accuracy.

[0234] The electrodes of the sensor elements included in the sensor element group 31A each have a first electrode and a second electrode, and the first and second electrodes may be arranged in the form of parallel lines, parallel curves, a comb shape, or concentric circles. Regardless of the shape of the first and second electrodes, it is preferable that they are arranged in line symmetry or point symmetry with each other. By arranging the first and second electrodes in this manner, the odor measuring device 100c can measure odor substances contained in gas with high accuracy.

[0235] Sensor element 31c of Fig. 14 has a first electrode 313C and a second electrode 313D. Furthermore, as an example, first electrode 313C is composed of metal wiring 313a and metal wiring 313b, and the two metal wirings are arranged in a T-shape so as to be perpendicular to each other. Similarly to first electrode 313C, second electrode 313B is also composed of two metal wirings 313c and 313d, and the two metal wirings are arranged in a T-shape so as to be perpendicular to each other. Furthermore, first electrode 313A and second electrode 313B are arranged in parallel lines so that metal wiring 313a and metal wiring 313c face each other.

[0236] The first electrode 313C and the second electrode 313D are particularly arranged in a T-shape, which allows the first electrode 313C and the second electrode 313D to be located at a suitable distance from each other, thereby stabilizing the electrode resistance. For example, if the electrodes were arranged in a comb-like shape, the distance between the electrodes would be too short, which could result in the electrode resistance being too low. Furthermore, the first electrode 313C and the second electrode 313D are arranged in a T-shape, which allows the slurry to spread easily in the application process of the sensor element manufacturing method described below, since there are no uneven portions of the electrodes that could hinder the slurry from spreading. Furthermore, the ease of spreading the slurry also has the effect of ensuring a consistent thickness of the odorant receptive layer after drying.

[0237] [Method of manufacturing sensor element] A manufacturing method for producing multiple types of sensor elements used in the odor measurement device 100c is described below. The odorant receiving layer of a sensor element can be made from slurries with various compositions, but the viscosity of each slurry varies depending on the slurry composition. When forming an odorant receiving layer by applying slurries with different viscosities using the same method, for example, a low-viscosity slurry will easily wet and spread on the substrate, while a high-viscosity slurry will not wet and spread on the substrate as easily. Thus, when applying slurries with different viscosities using the same manufacturing method, variations in the shape, area, and thickness of the odorant receiving layer after drying occur. Sensor elements manufactured using such odorant receiving layers have difficulty in stably measuring odorants. On the other hand, changing the manufacturing method depending on the viscosity of the slurry will result in a uniform odorant receiving layer without variations in shape, area, and thickness, but this increases manufacturing costs.

[0238] According to the manufacturing method of this embodiment, it is possible to manufacture multiple types of sensor elements with little variation in shape, area, and thickness even when using slurries with different compositions, i.e., different viscosities. Furthermore, since it is not necessary to change the manufacturing method depending on the viscosity, manufacturing costs can be reduced.

[0239] FIG. 16 is a flowchart illustrating steps in a manufacturing method for manufacturing a plurality of types of sensor elements used in the odor measuring device 100c.

[0240] <Slurry preparation process> First, multiple types of slurries with different resin and filler mixture ratios are prepared. The mixture ratio of resin and filler can be appropriately set depending on the desired sensitivity and detection specificity of the odorant receiving layer. The slurries may contain solvents and additives in addition to the resin and carbon black (S21).

[0241] <Electrode placement process> Next, electrodes are arranged on the substrate (S22). The electrodes may include a first electrode and a second electrode. The first electrode and the second electrode may be arranged in parallel straight lines, parallel curved lines, a comb shape, or concentric circles. Regardless of the shape of the first electrode and the second electrode, it is preferable that they are arranged in line symmetry or point symmetry with each other. By arranging the first electrode and the second electrode in this manner, the odor measuring device 100c can measure odor substances contained in gas with high accuracy.

[0242] As an example, in Figures 14 and 15, one set of electrodes (first electrode 313C and second electrode 313D) is arranged on one substrate 311, but multiple sets of electrodes may be arranged side by side on one substrate.

[0243] <Area definition process> Next, coating areas onto which the plurality of types of slurries are to be coated are defined on the substrate on which the electrodes are disposed (S23). The coating areas may be defined, for example, by disposing a resist. Furthermore, if the slurry is dropped from a nozzle in the coating process, the coating areas may be defined to match the nozzle diameter. FIG. 17 is a schematic diagram of the substrate 311 after the resist M has been disposed. The resist M is disposed so as to define a coating area 330. In the coating area 330, the substrate 311 is exposed.

[0244] The size of the application area 330 may be specified to be the same for each of the multiple types of slurries. That is, even if the slurries have different mixture ratios of filler, resin composition, and surfactant, the area of ​​the application area 330 for applying the slurries may be uniform. This reduces the variation in the area of ​​the multiple odorant receiving layers after drying, even when multiple types of slurries with different mixture ratios, i.e., different viscosities, are used.

[0245] 17 is circular as an example, but the shape of the coating area 330 is not limited to this. The shape of the coating area 330 may be circular or strip-shaped. This results in the formation of a circular or strip-shaped odorant receiving layer.

[0246] When the shape of the applied area 330 is circular, the diameter of the circle may be 0.2 mm or more and 10 mm or less, and when the shape of the applied area 330 is strip-shaped, the length of the strip in the short direction may be 0.2 mm or more and 10 mm or less. This results in the formation of a circular odorant receiving layer with a diameter of 0.2 mm or more and 10 mm or less, or a circular odorant receiving layer with a strip-like length in the short direction.

[0247] The method for applying the resist M is not particularly limited, but examples include a method of silk-screening the solder resist in a specified area and then UV-curing the solder resist, a method of attaching a resist film to a substrate, and a method of curing only the resist in a specified area and removing the uncured portion.

[0248] <Coating process> Next, each of the multiple types of slurries is applied to the application region 330 (S24). The method for applying the slurries may be a conventionally known method, and the slurries may be dropped from a nozzle, sprayed, or spin-coated.

[0249] The viscosities of the multiple types of slurries are different. The different viscosities of the slurries are caused, for example, by different mixing ratios of the filler, resin composition, and surfactant. Slurries with different viscosities may exhibit different wetting and spreading behavior. However, in the coating step of this manufacturing method, the coating area is defined in the previous area defining step, so the slurry is applied to the defined area.

[0250] <Drying process> Finally, the slurry applied to the application area 330 is dried to form an odorant receiving layer (S25). The method for drying the slurry is not particularly limited, but for example, it can be heated at 100°C for 1 hour at normal pressure, and then heated at 100°C for 1 hour while reducing the pressure in a vacuum dryer.

[0251] In the drying process, the thickness of the odorant receiving layer after drying may be 0.1 μm or more and 1000 μm or less. The thickness of the odorant receiving layer after drying may preferably be 1 μm or more and 100 μm or less. If the thickness of the odorant receiving layer is within the above range, the sensor element can stably measure odorants. If the thickness of the odorant receiving layer is less than 0.1 μm, the value will be close to the particle diameter of the filler dispersed in the odorant receiving layer, so the uniformity of the thickness of the odorant receiving layer cannot be guaranteed, and the odor measuring device 100c may not be able to output stable measurement results. On the other hand, if the thickness of the odorant receiving layer is greater than 1000 μm, the diffusion time of the odorant within the odorant receiving layer will be longer, making it difficult for the odor measuring device 100c to measure odorants with high accuracy.

[0252] As described above, the manufacturing method according to this embodiment includes a slurry preparation process, an electrode placement process, an area definition process, a coating process, and a drying process. By adopting this manufacturing method, it is possible to manufacture multiple types of sensor elements with little variation in the shape, area, and thickness of the odorant receiving layer, even when using multiple types of slurries with different mixing ratios of filler, resin composition, and surfactant. Furthermore, since there is no need to change the manufacturing method depending on the viscosity of the slurry, manufacturing costs can be reduced.

[0253] In particular, by defining the coating area in the area defining step, the wetting and spreading of the slurry droplets in the subsequent coating step is improved. For example, if the coating area is defined by resist, the surface roughness of the substrate will differ between the area where the resist is present and the area where the resist is not present. In the area where the resist is not present, the substrate is exposed, resulting in a high surface roughness and a low surface tension. This allows the wetting and spreading of the slurry droplets to be improved in the coating area where the substrate is exposed.

[0254] In addition, by arranging the coating area in the area definition process, the wetting and spreading of the slurry in the subsequent coating process is regulated, and the positional relationship between the odorant receiving layer and the electrode is constant. For example, if the coating area is defined by resist, a step is created at the resist boundary, which regulates the wetting and spreading of the slurry, and the positional relationship between the odorant receiving layer and the electrode is constant.

[0255] In addition, in this embodiment, the odorant receiving layer 315 is formed by coating the aforementioned resin composition. As described above, the resin composition has excellent compositional stability and coating stability, so it is possible to reduce the variation in performance between the odorant receiving layers 315 when multiple odorant receiving layers 315 are produced.

[0256] In addition, when preparing the odorant receiving layer, the odorant receiving layer may be prepared by coating a resin composition, and then an electrode may be prepared so as to be in contact with the odorant receiving layer.

[0257] [Software implementation example] The control block (particularly the control unit 1) of the estimation devices 10, 10a, and 10b may be realized by a logic circuit (hardware) formed on an integrated circuit (IC chip) or the like, or may be realized by software.

[0258] In the latter case, the estimation devices 10, 10a, and 10b each include a computer that executes instructions from a program, which is software that realizes each function. The computer includes, for example, one or more processors and a computer-readable recording medium that stores the program. The object of the present invention is achieved when the processor in the computer reads and executes the program from the recording medium. The processor may be, for example, a central processing unit (CPU). The recording medium may be a "non-transitory tangible medium," such as a read-only memory (ROM), tape, disk, card, semiconductor memory, or programmable logic circuit. The device may also include a random access memory (RAM) for loading the program. The program may be supplied to the computer via any transmission medium capable of transmitting the program (such as a communication network or broadcast waves). Note that one aspect of the present invention may also be realized in the form of a data signal embedded in a carrier wave, in which the program is embodied by electronic transmission.

[0259] Furthermore, some or all of the functions of the control blocks can be realized by logic circuits. For example, an integrated circuit in which a logic circuit that functions as each of the control blocks is formed is also included in the scope of the present invention. In addition, the functions of the control blocks can also be realized by, for example, a quantum computer.

[0260] Furthermore, each process described in each of the above embodiments may be executed by AI (Artificial Intelligence). In this case, the AI ​​may run on the control device or on another device (for example, an edge computer or a cloud server).

[0261] 〔summary〕 As is clear from the above explanation, the resin composition according to aspect 1 of the present disclosure is a resin composition for a chemiresistor sensor, and contains a resin (A) and carbon black (B), and the DBP oil absorption of the carbon black (B) is 300 ml / 100 g or less.

[0262] In the resin composition according to Aspect 2 of the present disclosure, the content of carbon black (B) may be 10 to 85% by weight, relative to 100% by weight of the total of (A) and (B).

[0263] In the resin composition according to Aspect 3 of the present disclosure, in either Aspect 1 or Aspect 2, the carbon black (B) may have a DBP oil absorption of 200 ml / 100 g or less.

[0264] A sensor element according to aspect 4 of the present disclosure is a sensor element comprising an odorant receiving layer containing a resin composition described in any one of aspects 1 to 3, a first metal wiring, and a second metal wiring, wherein the first metal wiring and the second metal wiring are spaced apart, and the odorant receiving layer may be in contact with at least a portion of the first metal wiring and at least a portion of the second metal wiring.

[0265] An odor sensor according to aspect 5 of the present disclosure may include at least one sensor element as described in aspect 4, a power source for powering the sensor element, and a measuring device for outputting a measurement value indicating the electrical conductivity of the odorant receiving layer of the sensor element powered by the power source.

[0266] In the odor sensor according to Aspect 6 of the present disclosure, in Aspect 5, the power source may supply a constant current or apply a constant voltage to the at least one sensor element.

[0267] An odor measuring device according to aspect 7 of the present disclosure is an odor measuring device comprising an odor sensor according to aspect 5 or 6, and an estimation device, wherein the estimation device comprises an acquisition unit that acquires the measurement values ​​from the measuring device, an analysis unit that analyzes the change in electrical conductivity of the at least one sensor element over time, and an estimation unit that estimates odor substances based on an estimation model, and the estimation model may be generated by machine learning using training data that includes a combination of measurement values ​​measured by the measuring device when each of a plurality of odor substances is adsorbed onto the at least one sensor element and identification information unique to the odor substance that provided the measurement values.

[0268] The odor control program of aspect 8 of the present disclosure is a control program for causing a computer to function as the odor measurement device described in aspect 7, and causes the computer to function as the acquisition unit, the analysis unit, and the estimation unit. [Example]

[0269] The present invention will be further described below with reference to examples and comparative examples, but the present invention is not limited thereto. Unless otherwise specified, % means % by weight and parts means parts by weight.

[0270] 〔material〕 <Resin (A)> Polystyrene (A-1) (Fujifilm Wako Pure Chemical Industries, styrene polymer) Polymethyl methacrylate (A-2) (Fujifilm Wako Pure Chemical Industries, methyl methacrylate polymer) <Carbon black (B)> Carbon black (B-1) (DBP oil absorption 30.5 ml / 100 g) (JFE Chemical Corporation, JCP-P6B) Carbon black (B-2) (DBP oil absorption: 82.8 ml / 100 g) (manufactured by Nippon Graphite Industries Co., Ltd., JB-3) Carbon black (B-3) (DBP oil absorption 53.8 ml / 100 g) (Tokai Carbon Co., Ltd., Toka Black #3800) Carbon black (B-4) (DBP oil absorption: 157.0 ml / 100 g) (Denka Black, manufactured by Denka Co., Ltd.) Carbon black (B-5) (DBP oil absorption: 273.0 ml / 100 g) (MTI Corporation, Super C-65) Carbon black (B-6) (DBP oil absorption: 344.0 ml / 100 g) (Ketjenblack EC-300J, manufactured by Lion Specialty Chemicals Co., Ltd.) [Examples 1 to 22, Comparative Examples 1 to 4] <Preparation of slurry> Resin (A) and carbon black (B) were weighed into containers in the amounts shown in Tables 1 to 3 and mixed with N-methylpyrrolidone as a solvent to obtain a mixture. The mixture was stirred at 2000 rpm for 10 minutes using a planetary centrifugal mixer (ARE-310, manufactured by Thinky Corporation) to obtain a slurry. This slurry was used as the resin composition for forming the odorant-receiving layer.

[0271] [DBP oil absorption] The DBP oil absorption of each carbon black was measured in accordance with JIS K 6217-4.

[0272] [Resistance measurement method] The resin composition of the example was used as an odor sensor element, and the resistance value of the odor sensor element before exposure to odor was measured using a digital multimeter DT4282 (manufactured by HIOKI Corporation).

[0273] [Method for measuring resistance change rate] Using a Permeator PD-1C (manufactured by Gastec Corporation), 4000 ppm ethanol gas and toluene gas were prepared. Then, while an electric current was being applied, the resin composition was brought into contact with the ethanol gas and the toluene gas for 30 seconds, respectively, and the rate of change in the resistance of the resin composition when brought into contact with each gas was measured.

[0274] [Resistance variation measurement method] Ten probe elements were prepared using each resin composition. The resistance of each probe element was measured before exposure to the odor using the same method as the resistance measurement method described above. The average and deviation values ​​were calculated from the measured resistance values, and the coefficient of variation was calculated using the deviation / average value formula. The resistance variation was evaluated based on the following evaluation criteria for the coefficient of variation. A: Coefficient of variation is 0.1 or less. B: Coefficient of variation is greater than 0.1 and less than or equal to 0.15. C: Coefficient of variation is greater than 0.15 and less than or equal to 0.2. D: The coefficient of variation is greater than 0.2.

[0275] [Result 1] The results are shown in Tables 1 to 3.

[0276] [Table 1]

[0277] [Table 2]

[0278] [Table 3]

[0279] As shown in Tables 1 and 2, resin compositions using carbon black with a DBP oil absorption of 300 ml / 100 g or less all had a large resistance change rate when contacted with ethanol and toluene. In particular, resin compositions using polymethyl methacrylate not only had a large resistance change rate when contacted with gas, but also had a large difference in the resistance change rate between ethanol and toluene. Furthermore, the smaller the DBP oil absorption, the greater the resistance value and resistance change rate.

[0280] On the other hand, as shown in Table 3, in Comparative Examples 1 to 4, which used carbon black with a DBP oil absorption of more than 300 ml / 100 g, the resistance change rate of the resin composition when it was contacted with ethanol and toluene fell to less than 0.2%. Furthermore, the results of Comparative Examples 2 and 4 show that when carbon black with a DBP oil absorption of 300 ml / 100 g or more was used, the resistance value variability increased.

[0281] Therefore, it was demonstrated that a highly sensitive odor identification sensor can be realized by using the resin composition according to one embodiment of the present invention. [Industrial Applicability]

[0282] The present invention is useful as a chemiresistor sensor for medical, gas detection, agricultural, and other industrial or daily uses. More specifically, it is useful as an odor identification sensor. For example, farmers can use the odor identification sensor to determine the maturity of fragrant crops and manage optimal harvest timing. Furthermore, the odor identification sensor can also be used to digitize the odors of products such as food and cosmetics, helping to improve the efficiency of product development and stabilize quality. [Explanation of symbols]

[0283] 10, 10a, 10b Estimation device 11 Measurement value acquisition unit (acquisition unit) 12 Change pattern analysis unit (analysis unit) 16 Estimation part 30, 30b Odor sensor 31, 31b, 31c, 31d sensor elements 32, 32b Constant current source (power supply) 33, 33b Voltmeter (measuring equipment) 100, 100a, 100b, 100c Odor measuring device 313A 1st metal wiring 313B 2nd metal wiring 315, 315b Odorant receptor layer 313C 1st electrode 313D 2nd electrode 330 Application area

Claims

1. A resin composition for a chemiresistor sensor, comprising: A resin (A) and carbon black (B), A resin composition, wherein the carbon black (B) has a DBP oil absorption of 300 ml / 100 g or less.

2. 2. The resin composition according to claim 1, wherein the content of carbon black (B) is 10 to 85% by weight, based on 100% by weight of the total of (A) and (B).

3. 2. The resin composition according to claim 1, wherein the carbon black (B) has a DBP oil absorption of 200 ml / 100 g or less.

4. A sensor element comprising an odorant receiving layer containing the resin composition according to any one of claims 1 to 3, a first metal wiring, and a second metal wiring, the first metal wiring and the second metal wiring are spaced apart, A sensor element, wherein the odorant receiving layer is in contact with at least a portion of the first metal wiring and at least a portion of the second metal wiring.

5. At least one sensor element according to claim 4; a power source for supplying power to the sensor element; An odor sensor comprising: a measuring device that outputs a measurement value indicating the electrical conductivity of the odorant receiving layer of the sensor element powered by the power source.

6. The odor sensor according to claim 5 , wherein the power source supplies a constant current or applies a constant voltage to the at least one sensor element.

7. An odor measurement device comprising the odor sensor and the estimation device according to claim 6, The estimation device includes: an acquisition unit that acquires the measurement values ​​from the measuring device; an analysis unit that analyzes a change in electrical conductivity of the at least one sensor element over time; an estimation unit that estimates odor substances based on an estimation model; An odor measurement device in which the estimation model is generated by machine learning using learning data that includes a combination of measurement values ​​measured by the measuring device when each of a plurality of odor substances is adsorbed onto at least one sensor element and identification information unique to the odor substance that provided the measurement value.

8. A control program for causing a computer to function as the odor measuring device according to claim 7, the control program causing a computer to function as the acquisition unit, the analysis unit, and the estimation unit.

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