Method for manufacturing sensitive membrane of odor sensor element, sensitive membrane of odor sensor element, odor sensor element, and odor sensor

Abstract

To increase the sensitivity of an odor sensor element, while improving the production stability of a sensitive membrane.SOLUTION: A resin composition solution (L1) is discharged from a nozzle (28) of a pipette-type dispenser (24) and is applied onto a substrate (12) to form a coating (F1) on the substrate (12), and the coating (F1) is dried to form a sensitive membrane (14). The amount of resin composition solution (L1) discharged from the nozzle (28) is 0.1 μL to 5.0 μL.SELECTED DRAWING: Figure 6

Description

[Technical field]

[0001] The present invention relates to a method for manufacturing a sensitive film of an odor sensor element, a sensitive film of an odor sensor element, an odor sensor element, and an odor sensor. [Background technology]

[0002] A known method for producing a sensitive film of an odor sensor element is, for example, that shown in Patent Document 1. In the production method described in Patent Document 1, a syringe-type dispenser is used. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2020-165971 A Summary of the Invention [Problem to be solved by the invention]

[0004] When forming a coating film on a substrate, the resin composition solution that has risen to the tip of the nozzle evaporates and solidifies, causing a change in the wettability of the tip of the nozzle. If the production of the sensitive film is continued in a state in which the wettability of the tip of the nozzle has changed, the amount of resin composition solution applied becomes unstable, reducing the production stability of the sensitive film, and the smoothness (smoothness) of the surface of the sensitive film decreases, resulting in a problem of a decrease in the sensitivity of the odor sensor element.

[0005] Therefore, one aspect of the present invention aims to provide a method for manufacturing a sensitive film of an odor sensor element that can improve the sensitivity of the odor sensor element while increasing the manufacturing stability of the sensitive film. [Means for solving the problem]

[0006] In order to solve the above-mentioned problems, the inventors of the present application have repeatedly conducted trial and error, and as a result, have discovered a new finding that by using a pipette-type dispenser equipped with a detachable nozzle at the tip and setting the amount of resin composition solution discharged from the nozzle to a predetermined amount, it is possible to increase the smoothness (smoothness) of the surface of the sensitive film while suppressing the resin composition solution from creeping up to the tip of the nozzle, and have completed the present invention. Here, the predetermined amount of discharge is 0.1 μL to 5.0 μL.

[0007] The manufacturing method according to the first aspect of the present invention is a method for manufacturing a sensitive film of an odor sensor element on a substrate, and includes the steps of: using a pipette-type dispenser equipped with a removable nozzle at the tip, sucking a resin composition solution containing an organic solvent from a container storing the resin composition solution into the nozzle; after the step of sucking, the resin composition solution is discharged from the nozzle and applied onto the substrate to form a coating film on the substrate; and after the step of coating, drying, the coating film is dried to form the sensitive film. The amount of the resin composition solution discharged from the nozzle is 0.1 μL to 5.0 μL.

[0008] The sensitive film of the odor sensor element according to the second aspect of the present invention is produced by the method for producing a sensitive film of an odor sensor element according to the first aspect of the present invention.

[0009] The odor sensor element according to the third aspect of the present invention includes a substrate and a sensitive film produced on the substrate by the method for producing a sensitive film of an odor sensor element according to the first aspect of the present invention.

[0010] An odor sensor according to a fourth aspect of the present invention includes the odor sensor element according to the third aspect of the present invention. Effect of the Invention

[0011] According to one aspect of the present invention, it is possible to improve the manufacturing stability of the sensitive film while improving the sensitivity of the odor sensor element. [Brief description of the drawings]

[0012] [Figure 1] FIG. 1 is a schematic plan view of an odor sensor element according to an embodiment of the present invention. [Diagram 2] FIG. 2 is a cross-sectional view taken along line II-II in FIG. [Diagram 3] 1 is an SEM image of a cross section of an odor sensor element. [Figure 4] 3A to 3C are schematic diagrams illustrating an inhalation step in a first manufacturing method for the sensitive film of the odor sensor element according to the present embodiment. [Diagram 5] 3A to 3C are schematic diagrams illustrating a coating step in a first manufacturing method for the sensitive film of the odor sensor element according to the present embodiment. [Figure 6] 3A to 3C are schematic diagrams illustrating a coating step in a first manufacturing method for the sensitive film of the odor sensor element according to the present embodiment. [Figure 7] 3A to 3C are schematic diagrams illustrating a drying step in a first method for producing the sensitive film of the odor sensor element according to the present embodiment. [Figure 8] 4A to 4C are schematic diagrams illustrating an inhalation step in a second manufacturing method for the sensitive film of the odor sensor element according to the present embodiment. [Figure 9] 4A to 4C are schematic diagrams illustrating a coating step in a second method for producing the sensitive film of the odor sensor element according to the present embodiment. [Figure 10] 4A to 4C are schematic diagrams illustrating a coating step in a second method for producing the sensitive film of the odor sensor element according to the present embodiment. [Figure 11] 4A to 4C are schematic diagrams illustrating a drying step in a second method for producing the sensitive film of the odor sensor element according to the present embodiment. [Figure 12] FIG. 1 is a schematic diagram illustrating an odor sensor according to an embodiment of the present invention. [Figure 13] FIG. 2 is a top view showing an example of the configuration of an odor sensor element according to the present embodiment. [Figure 14] 10 is a top view showing another example of the configuration of the odor sensor element according to the present embodiment. FIG. [Figure 15] 1 is a perspective view showing an example of the configuration of an odor sensor element according to an embodiment of the present invention; [Figure 16]FIG. 2 is a schematic diagram for explaining a method for producing a sensor substrate used in the examples. [Figure 17] FIG. 2 is a schematic diagram for explaining a method for producing a sensor substrate used in the examples. [Figure 18] FIG. 2 is a schematic diagram showing the configuration of the surface of a sensor substrate used in the examples. [Figure 19] FIG. 2 is a schematic diagram showing the configuration of the rear surface of a sensor substrate used in the examples. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0013] An embodiment of the present invention will be described below, but the present invention is not limited thereto. In addition, unless otherwise specified in this specification, "A to B" representing a numerical range means "A or more and B or less."

[0014] [Odor sensor element 10] First, an example of an odor sensor element having a sensitive film manufactured by applying a manufacturing method according to one aspect of the present invention will be described with reference to Fig. 1 and Fig. 2. Fig. 1 is a schematic plan view of an odor sensor element 10 according to this embodiment. Fig. 2 is a cross-sectional view taken along line II-II in Fig. 1.

[0015] (Outline of odor sensor element 10, odor substances) As shown in Figures 1 and 2, the odor sensor element 10 according to this embodiment is an odor sensor element for detecting odorants. The odor sensor element 10 includes a substrate 12, an odorant receiving layer 14, metal wiring 16, and an odorant permeation layer 20. Here, the manufacture of an odor sensor element having an odorant permeation layer and an odorant receiving layer will be described as an example, but is not limited to this. For example, the present invention can also be applied to the manufacture of an odor sensor element having only an odorant receiving layer, and an odor sensor element in which the arrangement of the metal wiring 16 is different from that shown in the figure.

[0016] Here, the "odor substance" is not particularly limited, but examples thereof include 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. "Odor substances" also include substances that are not generally considered to be the cause of odor. "Odor substances" include not only individual odor substances, but also multiple odor substances.

[0017] [Substrate 12] As shown in FIG. 1 and FIG. 2, the odor sensor element 10 includes a substrate 12, which is made of, for example, a glass epoxy plate. The substrate 12 may be made of paper phenol, glass composite, polyimide, PET (polyethylene terephthalate), glass ceramic, alumina, or aluminum. The substrate 12 has a structure that regulates the wetting and spreading of the resin composition solutions L1 and L2 described later. For example, as shown in FIG. 2, when the substrate 12 is viewed from the side, a region (coating region) where the resin composition solution (described later) is applied may be recessed compared to other regions of the substrate 12. The configuration in which the coating region is recessed compared to other regions of the substrate 12 may be formed, for example, by adding a solder resist to regions other than the coating region in the process of creating the substrate 12. Alternatively, a tape or the like may be attached to the outside of the coating region of the substrate 12. With these configurations, the coating region of the substrate 12 becomes lower than other regions. Therefore, even if the resin composition solution is applied to the substrate 12, the wetting and spreading of the resin composition solution is regulated, and the resin composition solution can be prevented from wetting and spreading beyond the applied area.

[0018] [Odorant Receptor Layer 14] As shown in Figures 1 and 2, the odor sensor element 10 has an odorant receiving layer 14 as a sensitive film provided on a substrate 12, and the odorant receiving layer 14 is capable of adsorbing odorants. The odorant receiving layer 14 is manufactured on the substrate 12 by a first manufacturing method (M1) of the sensitive film of the odor sensor element described below. The odorant receiving layer 14 is composed of a resin composition containing a resin and a conductive material as a filler. The electrical resistance value (electrical conductivity) of the odorant receiving layer 14 changes depending on the adsorption state of the odorant. The odor sensor element 10 is a chemiresistor-type odor sensor element that uses the change in the electrical resistance value of the odorant receiving layer 14 as a sensitive film as an indicator of odor detection.

[0019] The thickness of the odorant receiving layer 14 is 0.1 μm to 250 μm. It is preferably 0.1 μm to 200 μm, more preferably 0.1 μm to 120 μm, more preferably 0.1 μm to 50 μm, and even more preferably 1 μm to 25 μm. The thickness of the odorant receiving layer 14 may differ between the center and the edge. For example, as shown in FIG. 2, when the coating area of ​​the substrate 12 is recessed compared to other areas, the edge of the odorant receiving layer 14 formed by coating the coating area adheres to the substrate 12 and rises compared to the center. Therefore, the thickness of the edge tends to be thicker than the center. For example, the thickness of the center of the odorant receiving layer 14 may be about 1 to 6 μm, and the edge may be about 20 μm. The thickness of the odorant receiving layer 14 may be within the above-mentioned range as the average thickness of multiple locations including the center and edge. In addition, it is preferable that the thickness of the odorant receiving layer 14 is within the above-mentioned range throughout the entire layer, including the central portion and the end portions. By setting the thickness of the odorant receiving layer 14 within the above-mentioned range, the change in the electrical conductivity of the odorant receiving layer 14 caused by the adsorption of the odorant in the odorant receiving layer 14 can be accurately detected as an electrical signal. When creating the odorant receiving layer 14, the thickness of the odorant receiving layer 14 can be controlled by regulating the area of ​​the film to be applied using the electrode shape, etc., and controlling the evaporation residue and the amount of the odor permeation layer solution to be dispensed.

[0020] [Metal wiring 16] As shown in FIG. 1 and FIG. 2, the odor sensor element 10 includes a pair of metal wirings 16 provided on a substrate 12, the pair of metal wirings 16 being arranged parallel to each other and covered with an odorant receiving layer 14. The pair of metal wirings 16 function as electrodes for measuring changes in the electrical conductivity of the odorant receiving layer 14. Lead wires 18 are connected to the pair of metal wirings 16. The width of each metal wiring 16 is preferably 10 μm to 2 mm, more preferably 10 μm to 1 mm. The thickness of each metal wiring 16 is preferably 1 μm to 100 μm, more preferably 10 μm to 50 μm. The length of each metal wiring 16 is preferably 100 μm to 50 mm, more preferably 500 μm to 30 mm. The distance between the pair of metal wirings 16 is preferably 1 μm to 3 mm, more preferably 1 μm to 1.5 mm.

[0021] [Odor-permeable layer 20] As shown in FIG. 1 and FIG. 2, the odor sensor element 10 may have an odorant permeation layer 20 as another sensitive film provided to cover the odorant reception layer 14. The odorant permeation layer 20 is manufactured on the substrate 12 via the odorant reception layer 14 by the second manufacturing method (M2) of the sensitive film of the odor sensor element described later. The odorant permeation layer 20 has a function of selectively allowing odorants to reach the odorant reception layer 14. The odorant permeation layer 20 also functions as a protective layer that reduces the deterioration rate of the odorant reception layer 14 due to the humidity of the measurement environment. The odorant permeation layer 20 is composed of a resin composition containing a resin and zeolite (a general term for crystalline silicate) as a filler. The odorant permeation layer 20 may be composed of a resin composition containing a resin and a filler other than zeolite. The odorant permeation layer 20 may be composed of a resin composition that does not contain a filler. The following will explain the case of a resin composition containing a filler as an example.

[0022] The thickness of the odorant permeable layer 20 is 0.1 μm to 200 μm, and preferably 1 μm to 20 μm. The reason why the odorant permeable layer 20 is set to 0.1 μm or more is that if it is less than 0.1 μm, it will not be able to fully perform the function of selectively allowing odorants to reach the odorant receiving layer 14, and it will not be able to fully protect the odorant receiving layer 14. The reason why the odorant permeable layer 20 is set to 200 μm or less is that if it exceeds 200 μm, less odorants will reach the odorant receiving layer 14, and the measurement sensitivity of the odor sensor element 10 will decrease.

[0023] In addition, the odorant-permeable layer 20 serving as another sensitive film may be omitted from the configuration of the odor sensor element 10.

[0024] <Method for measuring the thickness of the odorant-permeable layer 20> The method for measuring the thickness of the odorant permeation layer 20 will be described below with reference to FIG. 3. FIG. 3 is a scanning electron microscope (SEM) image of the cross section of the odor sensor element 10 including the odorant reception layer 14 and the odorant permeation layer 20, observed at 25,000 times magnification. The cross section of the odor sensor element 10 including the odorant reception layer 14 and the odorant permeation layer 20 is formed, for example, using a cross-section polisher, specifically IB-19530CP (product name manufactured by JEOL Ltd.). The lines indicated by symbols X1 to X20 in FIG. 3 indicate the length from the boundary between the odorant reception layer 14 and the odorant permeation layer 20 to the surface of the odorant permeation layer 20 at each location. Hereinafter, the length from the boundary between the odorant reception layer 14 and the odorant permeation layer 20 to the surface of the odorant permeation layer 20 is referred to as the cross-sectional length of the odorant permeation layer 20. The boundary between the odorant receiving layer 14 and the odorant permeable layer 20 can be determined using, for example, SEM reflection observation, electron image SEM-EDX, or STEM.

[0025] The thickness of the odorant-permeable layer 20 may be the average value of the cross-sectional length at multiple locations of the odorant-permeable layer 20. The measurement locations of the cross-sectional length that are the calculation basis for the thickness of the odorant-permeable layer 20 may be the thickest and thinnest locations, or may be 10 locations arbitrarily selected from the odorant-permeable layer 20, or may be even more. As an example, the average value of the cross-sectional lengths at 20 locations indicated by symbols X1 to X20 in the example shown in FIG. 3 may be the thickness of the odorant-permeable layer 20. The thickness of the odorant-permeable layer 20 may be determined as long as the average value of the cross-sectional lengths at multiple locations falls within the above-mentioned numerical range.

[0026] <Method for measuring the thickness of odorant receiving layer 14> The thickness of the odorant receiving layer 14 may be measured using a method similar to that used to measure the thickness of the odorant permeation layer 20. When measuring the thickness of the odorant receiving layer 14, the length from the boundary between the odorant receiving layer 14 and the odorant permeation layer 20 to the surface of the substrate 12 is taken as the cross-sectional length of the odorant receiving layer 14.

[0027] [First manufacturing method of the sensitive film of the odor sensor element (M1)] A first method (M1) for producing the sensitive film of the odor sensor element according to this embodiment will be described with reference to Figs. 4 to 7. Fig. 4 is a schematic diagram for explaining the inhalation step (M1-2) in the first method (M1) for producing the sensitive film of the odor sensor element according to this embodiment. Figs. 5 and 6 are schematic diagrams for explaining the application step (M1-3) in the first method (M1) for producing the sensitive film of the odor sensor element according to this embodiment. Fig. 7 is a schematic diagram for explaining the drying step (M1-4) in the first method (M1) for producing the sensitive film of the odor sensor element according to this embodiment.

[0028] (Outline of the first manufacturing method (M1) of the sensitive film of the odor sensor element) As shown in FIG. 4 to FIG. 7, the first manufacturing method (M1) of the sensitive film of the odor sensor element according to this embodiment is a method for manufacturing an odorant receiving layer 14 as a sensitive film on a substrate 12. The first manufacturing method (M1) of the sensitive film of the odor sensor element according to this embodiment includes a preparation step (M1-1), an inhalation step (M1-2), an application step (M1-3), a drying step (M1-4), and an exchange step (M1-5). The specific contents of each step in the first manufacturing method (M1) of the sensitive film of the odor sensor element according to this embodiment are as follows. Before starting the first manufacturing method (M1), a step of preparing a substrate 12 on which metal wiring 16 is arranged in advance is performed. In addition, the substrate 12 to be prepared is provided with a structure that restricts the wetting and spreading of the resin composition solution L1 or L2 described later.

[0029] (Preparation process (M1-1)) An organic solvent is added to a resin composition containing a resin and a conductive material as a filler, and the mixture is uniformly kneaded with a stirrer to produce a slurry-like resin composition solution L1 (see FIG. 4), which is then stored in a container 22 (see FIG. 4). The resin composition solution L1 may contain a surfactant. As an example, when preparing about 10 ml of the resin composition solution L1, the container 22 may be a screw tube with a capacity of about 20 ml.

[0030] Here, the resin contained in the resin composition solution L1 is not particularly limited, but may be, for example, a urethane resin, a polyalkylene oxide, an acrylic resin, a fluorine-containing resin, a vinyl resin (e.g., polyvinylpyrrolidone, polyvinyl butyral, etc.), a silicone resin, a polyamide resin, or a polyester resin.

[0031] The resin composition solution L1 may contain a filler. The conductive material contained in the resin composition solution L1 as a filler is a conductive carbon material, more specifically, a carbon material having a volume resistivity of 0.25 Ω·cm or less. Examples of the conductive carbon material include carbon black, carbon nanotubes, and graphene. The conductive carbon material is preferably fibrous or spherical in shape. When the conductive carbon material is fibrous, the fiber diameter is preferably 0.1 μm to 10 μm, and more preferably 0.1 μm to 5 μm. The fiber length is preferably 0.1 μm to 10 μm, and more preferably 1 μm to 10 μm. When the conductive carbon material is spherical, the primary particle diameter is preferably 10 nm to 200 nm, and more preferably 20 nm to 150 nm.

[0032] The conductive materials dispersed in the resin come into contact with each other to form conductive paths, which gives the resin composition electrical conductivity. In order to ensure sufficient electrical conductivity and sufficient sensitivity of the odor sensor element 10, the content of the conductive material is preferably 10% by weight to 70% by weight, where the total amount of the resin composition is 100% by weight.

[0033] The surfactant contained in the resin composition solution L1 acts as a dispersant for the conductive material. The surfactant can be appropriately selected from known surfactants such as ionic surfactants. Examples of the ionic surfactant include anionic surfactants, cationic surfactants, amphoteric surfactants, and nonionic surfactants.

[0034] The organic solvent contained in the resin composition solution L1 is not particularly limited, but examples thereof include N-methyl-2-pyrrolidone, propylene glycol monomethyl ether acetate, ethyl butyrate, diethylene glycol monobutyl ether, butyl butyrate, ethyl acetate, N,N-dimethylformamide, N,N-dimethylacetamide, toluene, xylene, diethylene glycol monobutyl ether acetate, and dibenzyl ether.

[0035] The viscosity of the resin composition solution L1 measured by an E-type viscometer (not shown) is 1 mPa·s to 500 mPa·s, and preferably 1 mPa·s to 300 mPa·s. The viscosity of the resin composition solution L1 is set to 1 mPa·s or more because if it is less than 1 mPa·s, there is a high possibility that the resin composition solution L1 will leak from the tip of the nozzle 28 (see FIG. 4) after being sucked up. The viscosity of the resin composition solution L1 is set to 500 mPa·s or less because if it exceeds 500 mPa·s, the resin composition solution L1 will not wet and spread after being applied onto the substrate 12. The viscosity is measured using an E-type viscometer [model "TV-22", manufactured by Toki Sangyo Co., Ltd.] with a cone rotor of 1°34'×R24, a measurement temperature of 25° C., and a rotor rotation speed of 2 rpm, and the value is read 60 seconds after the start of measurement.

[0036] The boiling point of the organic solvent contained in the resin composition solution L1 is 150°C to 250°C. The reason why the boiling point of the organic solvent is set to 150°C or more is that if it is less than 150°C, the organic solvent volatilizes during storage of the resin composition solution L1, causing a change in the solid content rate. Here, the solid content rate of the resin composition solution L1 refers to the ratio of the solid content to the entire resin composition solution L1, and may be, for example, the ratio of the weight of a certain amount of the resin composition solution L1 before drying to the weight after drying. The reason why the boiling point of the organic solvent is set to 250°C or less is that if it exceeds 250°C, the organic solvent cannot be completely removed in the drying step (M1-4). The boiling point means the boiling point under 1 atmosphere (101325 Pa). The boiling point is a value measured by a boiling point meter, and can be measured using, for example, DosaTherm300 manufactured by Titan Technologies Co., Ltd.

[0037] The solid content of the resin composition solution L1 is 2% to 20%. The reason why the solid content of the resin composition solution is set to 2% or more is that if it is less than 2%, the coating film thickness after drying will be thin, and the surface smoothness of the odorant receiving layer 14 as a sensitive film will decrease. The reason why the solid content of the resin composition solution L1 is set to 20% or more is that if it exceeds 20%, the viscosity of the resin composition solution L1 will increase, making it difficult to suck up the resin composition solution L1 with the nozzle 28. The solid content of the resin composition solution L1 is a value indicating the proportion of solids in the resin composition solution L1, and is a non-volatile content measured based on JIS K0067:1992. However, the resin composition solution L1 was dried using a vacuum dryer at a drying temperature of 100°C and for 2 hours.

[0038] The thixotropic index of the resin composition solution L1 measured by a rheometer (not shown) is 1.05 to 5.00. The reason why the thixotropic index of the resin composition solution L1 is set to 1.05 or more is that if it is less than 1.05, it is difficult to suck up the resin composition solution L1 with the nozzle 28 and to apply it. The reason why the thixotropic index of the resin composition solution L1 is set to 5.00 or less is that if it exceeds 5.00, the structure of the resin composition solution L1 is easily destroyed by shear applied during sucking up or application.

[0039] Thixotropy refers to the phenomenon in which viscosity decreases as the shear rate increases. The thixotropic index (TI value) is generally used as an index of thixotropy. The TI value is the value obtained by dividing the viscosity at a low shear rate by the viscosity at a high shear rate, and a value greater than 1 is said to have thixotropy. Using an E-type viscometer [model "TV-22", manufactured by Toki Sangyo Co., Ltd.], the cone rotor is 1°34'×R24, the measurement temperature is 25°C, and the rotor speed is 2 rpm. The value 60 seconds after the start of measurement (viscosity at 2 rpm) is read. Furthermore, the value 60 seconds after the start of measurement is read at 20 rpm (viscosity at 20 rpm). The value obtained by dividing the viscosity at 2 rpm by the viscosity at 20 rpm is taken as the thixotropic index.

[0040] (Inhalation process (M1-2)) During or after the preparation step (M1-1), a pipette-type dispenser 24 shown in FIG. 4 is prepared. Here, the pipette-type dispenser 24 includes a pipette 26 capable of sucking and discharging air, and a nozzle 28 detachably provided at the tip of the pipette 26. The nozzle 28 is sometimes called a pipette tip, and a nozzle 28 having a size that matches the amount of resin composition solution L1 to be applied is used. In this embodiment, for example, a 10 μL nozzle 28 is used. As the shape of the nozzle 28, a standard type is used, but a long type or a tapered type may also be used. As the nozzle 28, a resin nozzle generally available on the market may be used, and as the resin constituting the nozzle 28, for example, polypropylene is used.

[0041] 4, a pipette-type dispenser 24 is used to immerse a nozzle 28 in the resin composition solution L1 stored in a container 22. Then, the resin composition solution L1 is sucked from the container 22 into the nozzle 28 by a suction operation of the pipette 26.

[0042] (Coating process (M1-3)) After the suction step (M1-2) is completed, the tip of the nozzle 28 is brought close to a predetermined site on the substrate 12 while facing the same, as shown in Fig. 5. Then, the resin composition solution L1 is discharged from the nozzle 28 by the discharge operation of the pipette 26, and applied to the predetermined site on the substrate 12. This makes it possible to form a coating film F1 at the predetermined site on the substrate 12, as shown in Fig. 6. The distance between the tip of the nozzle 28 and the substrate 12 may be, for example, 0.3 mm.

[0043] Here, the amount of the resin composition solution L1 discharged from the nozzle 28 is 0.1 μL to 5.0 μL, preferably 0.1 μL to 1 μL. The reason why the amount of the resin composition solution L1 discharged is 0.1 μL or more is that if it is less than 0.1 μL, it becomes difficult to stably form the coating film F1 on the substrate 12. The reason why the amount of the resin composition solution L1 discharged is 5.0 μL or less is that if it exceeds 5.0 μL, it becomes difficult to improve the smoothness (smoothness) and uniformity of the surface of the coating film F1, that is, the smoothness (smoothness) and uniformity of the surface of the odorant receiving layer 14 as a sensitive film.

[0044] In the first manufacturing method (M1) of the sensitive film of the odor sensor element according to the present embodiment, the coating step (M1-3) may be repeated multiple times. The coating step (M1-3) is a step performed to form the coating film F1 at different positions, and is not a step of coating the resin composition solution L1 in one place. For example, the coating step (M1-3) may be performed once at each of multiple positions on one substrate 12, or the coating step (M1-3) may be performed once on each of multiple substrates 12. By repeating the coating step (M1-3) multiple times, it is possible to create one substrate 12 on which the coating film F1 is formed at multiple predetermined positions, or to create multiple substrates 12 on which the coating film F1 is formed at predetermined positions on the substrate 12. In addition, when the coating step (M1-3) is repeated multiple times using the same nozzle 28, it is not necessary to replace the nozzle 28 for each coating step (M1-3). This allows application to be performed without wasting the resin composition solution L1 remaining in the nozzle 28 after one application step (M1-3). In addition, since the time required for replacing the nozzle 28 can be saved, the production speed of the odor sensor element 10 can be improved.

[0045] (Drying process (M1-4)) After the coating process (M1-3) is completed, the coating film F1 is dried to form the odorant receiving layer 14 as a dried solid, as shown in Fig. 7. This allows the odorant receiving layer 14 to be produced as a sensitive film on the substrate 12.

[0046] The drying method of the coating film F1 is not particularly limited, but may be, for example, heating at 100°C under normal pressure for 1 hour, and then heating at 100°C for 1 hour while reducing the pressure in a vacuum dryer. In the drying step (M1-3), it is sufficient to be able to dry the coating film F1, and the temperature and reduced pressure conditions are not limited to those described above. For example, in the drying step (M1-3), the temperature when drying the coating film F1 may be 40°C to 160°C. In addition, the temperature during drying may vary, such as gradually increasing. Furthermore, the time for which the pressure is reduced in the drying step (M1-3) may be 0.5 hours to 3 hours, for example, 2 hours. In addition, reducing the pressure in the drying step (M1-3) is not essential, and may be omitted.

[0047] (Replacement process (M1-5)) The nozzle 28 is replaced every time the application step (M1-3) is performed a predetermined number of times. Specifically, after the application step (M1-3) is performed a predetermined number of times, the used nozzle 28 is detached from the tip of the pipette 26, and an unused nozzle 28 is attached to the tip of the pipette 26. Here, the predetermined number of times can be set arbitrarily depending on the degree to which the resin composition solution L1 creeps up to the tip of the resin composition in the nozzle 28, and may be 1 time, 10 times, or 30 times.

[0048] According to the configuration of the first manufacturing method of the sensitive film of the odor sensor element 10 of this embodiment, as described above, a pipette-type dispenser 24 equipped with a removable nozzle 28 at its tip is used, and the resin composition solution L1 is discharged from the nozzle 28 and applied to a predetermined portion on the substrate 12 to form a coating film F1 at the predetermined portion on the substrate 12. The amount of the resin composition solution L1 discharged from the nozzle 28 is 0.1 μL to 5.0 μL. Therefore, while suppressing the resin composition solution L1 from creeping up to the tip of the nozzle 28, the smoothness (smoothness) of the surface of the coating film F1 can be increased, and the smoothness of the surface of the odorant receiving layer 14 as the sensitive film can be increased. As a result, according to the first manufacturing method of the sensitive film of the odor sensor element 10 of this embodiment, the manufacturing stability of the odorant receiving layer 14 can be improved, while the sensitivity of the odor sensor element 10 can be improved.

[0049] When the resin composition solution L1 is sucked using a nozzle 28 that has sucked the resin composition solution L1 a predetermined number of times or more, the effect of the resin composition solution L1 creeping up to the tip of the nozzle 28 becomes large. Therefore, the nozzle 28 is replaced every time the application process (M1-3) is performed a predetermined number of times. This makes it possible to suppress the resin composition solution L1 creeping up to the tip of the nozzle 28, while further increasing the smoothness of the surface of the odorant receiving layer 14 and further improving the sensitivity of the odor sensor element 10.

[0050] When the resin composition solution L1 contains a conductive material (conductive carbon material) as a filler, the nozzle 28 can drain the liquid better, thereby further improving the manufacturing stability of the odorant receiving layer 14, and the resin ratio in the odorant receiving layer 14 can be reduced to further improve the sensitivity of the odor sensor element 10.

[0051] [Second manufacturing method (M2) of the sensitive film of the odor sensor element 10] The second manufacturing method (M2) of the sensitive film of the odor sensor element 10 according to this embodiment will be described with reference to Figs. 8 to 11. Fig. 8 is a schematic diagram illustrating the suction step (M2-2) in the second manufacturing method (M2) of the sensitive film of the odor sensor element 10 according to this embodiment. Figs. 9 and 10 are schematic diagrams illustrating the application step (M2-3) in the second manufacturing method (M2) of the sensitive film of the odor sensor element 10 according to this embodiment. Fig. 11 is a schematic diagram illustrating the drying step (M2-4) in the second manufacturing method of the sensitive film of the odor sensor element 10 according to this embodiment.

[0052] (Outline of the second manufacturing method (M2) of the sensitive film of the odor sensor element 10) As shown in Figs. 8 to 11, the second manufacturing method (M2) of the sensitive film of the odor sensor element 10 according to this embodiment is a method for manufacturing an odorant permeable layer 20 as a sensitive film on a substrate 12 via an odorant receiving layer 14. The second manufacturing method (M2) of the sensitive film of the odor sensor element 10 according to this embodiment includes a preparation step (M2-1), an inhalation step (M2-2), an application step (M2-3), a drying step (M2-4), and an exchange step (M2-5). The specific contents of each step in the second manufacturing method (M2) of the sensitive film of the odor sensor element 10 according to this embodiment are as follows. Note that if the odor sensor element 10 does not have an odorant permeable layer 20, each step in the second manufacturing method (M2) is omitted.

[0053] (Preparation process (M2-1)) An organic solvent is added to a resin composition containing a resin and a filler, and the mixture is uniformly kneaded with a stirrer to produce a resin composition. The resin composition may or may not contain a filler. The resin composition is then dissolved to produce a resin composition solution L2 (see FIG. 8), which is then placed in a container 30 (see FIG. 8). The resin composition solution L2 may contain a surfactant. The container 30 may be a container of the same shape as the container 22.

[0054] Here, the resin contained in the resin composition solution L2 is not particularly limited, but may be, for example, a vinyl resin (e.g., polyvinylpyrrolidone, polyvinyl butyral, etc.) or a silicone resin, a urethane resin, a polyalkylene oxide, an acrylic resin, a fluorine-containing resin, a vinyl resin (e.g., polyvinylpyrrolidone, polyvinyl butyral, etc.), a silicone resin, a polyamide resin, or a polyester resin.

[0055] The organic solvent contained in the resin composition solution L2 is not particularly limited, but may be the same as the organic solvent contained in the resin composition solution L1 (see FIG. 4).

[0056] The viscosity of the resin composition solution L2 measured using an E-type viscometer is 1 mPa·s to 500 mPa·s, and preferably 1 mPa·s to 300 mPa·s, for the same reasons as those for setting the viscosity of the resin composition solution L1. The boiling point of the organic solvent contained in the resin composition solution L2 is 150°C to 250°C for the same reasons as those for setting the boiling point of the organic solvent contained in the resin composition solution L1.

[0057] The solid content of the resin composition solution L2 is 2% to 20% for the same reason as that of the resin composition solution L1, and the thixotropic index of the resin composition solution L2 measured with a rheometer (not shown) is 1.05 to 5.00 for the same reason as that of the resin composition solution L1.

[0058] (Inhalation process (M2-2)) After the preparation step (M2-1) is completed, as shown in Fig. 8, a pipette-type dispenser 24 is used to immerse a nozzle 28 in the resin composition solution L2 stored in a container 30. Then, the resin composition solution L2 is sucked from the container 30 into the nozzle 28 by a suction operation of the pipette 26.

[0059] (Coating process (M2-3)) After the suction process (M2-2) is completed, the tip of the nozzle 28 is brought close to the application surface to a distance of about 0.3 mm, facing a predetermined portion on the substrate 12, as shown in Fig. 9. Then, the pipette 26 is discharged to discharge the resin composition solution L2 from the nozzle 28, and the predetermined portion on the substrate 12 is applied so as to cover the odorant receiving layer 14. This allows a coating film F2 to be formed on the predetermined portion on the substrate 12 via the odorant receiving layer 14, as shown in Fig. 10.

[0060] Here, the amount of the resin composition solution L2 discharged from the nozzle 28 is 0.1 μL to 5.0 μL, preferably 0.1 μL to 1 μL, for the same reason as for setting the amount of the resin composition solution L1 discharged from the nozzle 28.

[0061] In the second manufacturing method (M2) of the sensitive film of the odor sensor element 10 according to this embodiment, the coating step (M2-3) may be repeated multiple times. By repeating the coating step (M2-3) multiple times, it is possible to form a coating film F2 via an odorant receiving layer 14 at predetermined positions on multiple substrates 12, or to form a coating film F2 via an odorant receiving layer 14 at multiple predetermined positions on the substrate 12.

[0062] (Drying process (M2-4)) After the coating process (M2-3) is completed, the coating film F2 is dried to form the odorant permeable layer 20 as a dried solid, as shown in Fig. 11. This allows the odorant permeable layer 20 as a sensitive film to be produced on the substrate 12 via the odorant receiving layer 14.

[0063] The drying method for the coating film F2 is not particularly limited, and may be the same as the drying method for the coating film F1. The conditions such as drying temperature and time in the drying step (M2-3) for the coating film F2 may be the same as or different from the conditions such as drying temperature and time in the drying step (M1-3) for the coating film F1.

[0064] (Replacement process (M2-5)) After performing the application step (M2-3) a predetermined number of times (including once), the nozzle 28 is replaced. Specifically, after performing the application step (M2-3) a predetermined number of times, the used nozzle 28 is detached from the tip of the pipette 26, and an unused nozzle 28 is attached to the tip of the pipette 26.

[0065] According to the configuration of the second manufacturing method of the sensitive film of the odor sensor element according to the present embodiment, as described above, a pipette-type dispenser 24 equipped with a removable nozzle 28 at its tip is used, and the resin composition solution L2 is discharged from the nozzle 28 to be applied to a predetermined portion of the substrate 12 so as to cover the odorant receiving layer 14, thereby forming a coating film F2 on the predetermined portion of the substrate 12 via the odorant receiving layer 14. The amount of the resin composition solution L2 discharged from the nozzle 28 is 0.1 μL to 5.0 μL. Therefore, while suppressing the resin composition solution L2 from creeping up to the tip of the nozzle 28, the smoothness (smoothness) of the surface of the coating film F2 can be increased, and the smoothness of the surface of the odorant permeation layer 20 as the sensitive film can be increased. As a result, according to the second manufacturing method of the sensitive film of the odor sensor element according to the present embodiment, the manufacturing stability of the odorant permeation layer 20 can be improved, while improving the sensitivity of the odor sensor element 10.

[0066] When replacing the nozzle 28 after performing the application step (M2-3) a predetermined number of times, the resin composition solution L2 is not sucked again using the nozzle 28 that has sucked the resin composition solution L2 once. This makes it possible to more sufficiently prevent the resin composition solution L2 from creeping up to the tip of the nozzle 28, to further increase the smoothness of the surface of the odorant-permeable layer 20, and to further improve the sensitivity of the odor sensor element 10.

[0067] When the resin composition solution L2 contains zeolite as a filler, the nozzle 28 is well drained, the manufacturing stability of the odorant permeable layer 20 is improved, and the resin ratio in the odorant permeable layer 20 is reduced to further improve the sensitivity of the odor sensor element 10. The substance contained as a filler in the resin composition solution L2 is not limited to zeolite, and may be inorganic particles or resin particles different from zeolite.

[0068] [Odor Sensor 32] An example of the configuration of an odor sensor including an odor sensor element 10 will be described with reference to Fig. 12. Fig. 11 is a schematic diagram illustrating an odor sensor 32 according to this embodiment. Fig. 12 shows an odor sensor 32 including one odor sensor element 10, but is not limited to this. For example, the odor sensor 32 may be configured to include a plurality of odor sensor elements 10 having different resin compositions.

[0069] (Outline of odor sensor 32, housing 34, target sample receiving section 36) As shown in FIG. 12, the odor sensor 32 according to this embodiment is a sensor for detecting an odor substance, and includes an odor sensor element 10. The odor sensor 32 includes a housing 34 for housing the odor sensor element 10. The housing 34 is formed with an inlet 34i for introducing odorous substance-containing air into the housing 34, and an outlet 34e for discharging odorous substance-containing air from the housing 34 is formed at a position in the housing 34 away from the inlet 34i. The inlet 34i of the housing 34 is connected to a target sample receiving section 36 as a front chamber for containing the odorous substance-containing gas generated from the target sample. The odorous substance-containing gas generated from the target sample and contained in the target sample receiving section 36 is introduced into the housing 34 by sending, for example, nitrogen and air to the target sample receiving section 36.

[0070] (Constant voltage power supply 38, voltmeter 40) The odor sensor 32 includes a constant voltage power supply 38 as a power supply for supplying power to the odor sensor element 10, and the constant voltage power supply 38 is connected to the pair of metal wirings 16 via the lead wires 18. The constant voltage power supply 38 supplies a constant voltage to the odor sensor element 10 via the lead wires 18. The voltage value supplied by the constant voltage power supply 38 is 0.5 V to 10 V, for example, 2.5 V or 5.0 V. The odor sensor 32 also includes a voltmeter 40 as a measuring device for measuring the potential difference between the pair of metal wirings 16 when a constant voltage is supplied from the constant voltage power supply 38 to the odorant receiving layer 14. The voltmeter 40 is connected to the pair of metal wirings 16 via the lead wires 18. The voltmeter 40 is connected to an analyzer (not shown), and the analyzer calculates a value indicating the electrical conductivity of the odor sensor element 10 (for example, electrical resistance value and impedance, etc.) based on the measured value output from the voltmeter 40.

[0071] In addition, the odor sensor 32 includes an amplifier (not shown) in front of the voltmeter 40 in the odor substance measurement circuit, and the amplifier amplifies the acquired signal and supplies it to the voltmeter 40. In addition to the odor substance measurement circuit, the odor sensor 32 also includes a reference circuit (not shown), and the voltmeter 40 acquires the difference (potential difference) between the value acquired in the odor substance measurement circuit and the value acquired in the reference circuit as a voltage value.

[0072] The odor sensor 32 may include a constant current source (power supply) (not shown) instead of the constant voltage power supply 38, and an ammeter (measuring device) (not shown) instead of the voltmeter 40. In this case, the constant current source functions as a power supply for supplying power to the odor sensor element 10, and applies a constant current to the odor sensor element 10 via the lead wire 18. Meanwhile, the ammeter measures the value of the current flowing between the pair of metal wirings 16 when a constant current is applied to the odorant receptive layer 14.

[0073] <Configuration Example of Odor Sensor Element 10> FIG. 13 is a top view showing an example of the configuration of an odor sensor element 10A, which is an example of one odor sensor element 10 included in the odor sensor 32. The odor sensor element 10A includes a pair of metal wirings 16 arranged on a substrate 12, and a circular odorant receiving layer 14A formed on the metal wirings 16. Although not shown in FIG. 13, the odor sensor element 10A may include an odorant permeable layer 20. The pair of metal wirings 16 includes a first metal wiring 16A and a second metal wiring 16B. The first metal wiring 16A and the second metal wiring 16B are metal wirings that function as electrodes for measuring changes in the electrical conductivity of the odorant receiving layer 14A. The diameter R of the odorant receiving layer 14A is 0.2 mm or more and 5 mm or less. In FIG. 13, the shape of the odorant receiving layer 14A included in the odor sensor element 10A is elliptical as an example, but is not limited thereto. When the odorant receiving layer 14A has an elliptical shape, the average of the minor axis and the major axis may be 0.2 mm or more and 5 mm or less. The odorant receiving layer 14A may have a perfect circle shape.

[0074] FIG. 14 is a top view showing an odor sensor element 10B, which is another example of an odor sensor element 10. The odor sensor element 10B comprises metal wiring 16 (first metal wiring 16A, second metal wiring 16B) arranged on a substrate 12, and a strip-shaped odorant receiving layer 14B formed on the metal wiring 16. The length W of the short width of the odorant receiving layer 14B is 0.2 mm or more and 5 mm or less. In the following description, when there is no particular distinction between the odorant receiving layers 14A and 14B, they will be collectively referred to as "odorant receiving layer 14."

[0075] The metal wiring 16 of the odor sensor element 10 included in the odor sensor 32 has a first metal wiring and a second metal wiring, and the first metal wiring and the second metal wiring may be arranged in the form of parallel lines, parallel curves, a comb shape, or concentric circles. Regardless of which shape is adopted, the first metal wiring and the second metal wiring are preferably arranged in line symmetry or point symmetry with each other. By arranging the first metal wiring and the second metal wiring in this way, the odor sensor 32 can measure odor substances contained in the gas with high accuracy.

[0076] The odor sensor element 10A of Fig. 13 has a first metal wiring 16A and a second metal wiring 16B. As an example, the first metal wiring 16A is an electrode composed of a metal wiring 161A and a metal wiring 161B, and the two metal wirings are arranged in a T-shape so as to be perpendicular to each other. The second metal wiring 16B is an electrode composed of two metal wirings 161C and 161D, similar to the first metal wiring 16A, and is configured so as to be arranged in a T-shape so as to be perpendicular to each other. The first metal wiring 16A and the second metal wiring 16B are arranged in parallel lines so that the metal wiring 161A and the metal wiring 161C face each other.

[0077] For example, when the metal wiring 16 is arranged in a comb shape, the distance between the first metal wiring 16A and the second metal wiring 16B becomes short, and the resistance value of the metal wiring 16 may become too small. In contrast, the first metal wiring 16A and the second metal wiring 16B are arranged in a T-shape, so that the first metal wiring 16A and the second metal wiring 16B can be arranged at a suitable distance, and the resistance value of the metal wiring 16 (electrode) can be stabilized. In addition, since the first metal wiring 16A and the second metal wiring 16B are arranged in a T-shape, there are no uneven parts of the metal wiring 16 that may hinder the spreading of the resin composition at the end of the region where the resin composition spreads in the coating process of the manufacturing method of the odor sensor element 10 described above, so that the resin composition spreads easily. In addition, since the resin composition spreads easily, there is an effect that the thickness of the odorant receiving layer 14 and the odorant permeation layer 20 after drying becomes constant.

[0078] Fig. 15 is a perspective view showing an example of the configuration of one odor sensor element 10A. As shown in Fig. 15, in the odor sensor element 10A, the first metal wiring 16A and the second metal wiring 16B are connected to pins 22 at the ends where the first metal wiring 16A and the second metal wiring 16B do not face each other. The pins 22 are conductive members for electrically connecting the first metal wiring 16A and the second metal wiring 16B to other members of the odor sensor 32. Although not shown, the odor sensor element 10B shown in Fig. 14 also has the pins 22 shown in Fig. 15.

[0079] 〔summary〕 The method for producing a sensitive film of an odor sensor element according to the first aspect of the present invention is a method for producing a sensitive film of an odor sensor element on a substrate, and includes the steps of: using a pipette-type dispenser equipped with a removable nozzle at the tip, sucking a resin composition solution containing an organic solvent from a container storing the resin composition solution into the nozzle; after the step is completed, discharging the resin composition solution from the nozzle and applying it onto the substrate to form a coating film on the substrate; and after the step is completed, drying the coating film to form the sensitive film. The amount of the resin composition solution discharged from the nozzle is 0.1 μL to 5.0 μL.

[0080] In the method for producing a sensitive film of an odor sensor element according to aspect 2 of the present invention, in the above-mentioned aspect 1, the viscosity of the resin composition solution may be 1 mPa·s to 500 mPa·s, and the boiling point of the organic solvent may be 150°C to 250°C.

[0081] In the method for producing a sensitive film of an odor sensor element according to aspect 3 of the present invention, in the above-mentioned aspect 1 or 2, the solid content of the resin composition solution may be 2% to 20%.

[0082] In the method for producing a sensitive film of an odor sensor element according to aspect 4 of the present invention, in any one of aspects 1 to 3, the thixotropic index of the resin composition solution measured with a rheometer may be 1.05 to 5.00.

[0083] In the method for producing a sensitive film of an odor sensor element according to a fifth aspect of the present invention, in any one of the first to fourth aspects, the resin composition solution may contain a filler.

[0084] In the method for producing a sensitive film of an odor sensor element according to a sixth aspect of the present invention, in the fifth aspect, the filler may be a conductive material.

[0085] In the method for producing a sensitive film of an odor sensor element according to a seventh aspect of the present invention, in the sixth aspect, the conductive material may be a conductive carbon material.

[0086] In the method for producing a sensitive film of an odor sensor element according to an eighth aspect of the present invention, in the fifth aspect, the filler may be zeolite.

[0087] The method for manufacturing a sensitive film of an odor sensor element according to aspect 9 of the present invention, in any one of aspects 1 to 8, may further include a replacement step of replacing the nozzle every time the application step is performed a predetermined number of times.

[0088] A method for manufacturing a sensitive film of an odor sensor element according to aspect 10 of the present invention may be such that, in any one of aspects 1 to 9, the odor sensor element is a chemiresistor-type odor sensor element that uses a change in the electrical resistance value of the sensitive film as an odor detection indicator.

[0089] The sensitive film of the odor sensor element according to aspect 11 of the present invention is manufactured by the method for manufacturing the sensitive film of the odor sensor element according to any one of aspects 1 to 10.

[0090] The odor sensor element according to a twelfth aspect of the present invention includes a substrate and a sensitive film produced on the substrate by the method for producing a sensitive film of the odor sensor element according to any one of the first to tenth aspects.

[0091] In the odor sensor element according to Aspect 13 of the present invention, in the above-mentioned Aspect 12, the sensitive film may be an odorant-receiving layer.

[0092] In the odor sensor element according to Aspect 14 of the present invention, in the above-mentioned Aspect 12, the sensitive film may be an odorant-permeable layer.

[0093] An odor sensor according to a fifteenth aspect of the present invention includes the odor sensor element according to any one of the twelfth to fourteenth aspects.

[0094] [Additional Notes] The present invention is not limited to the above-described embodiments, and various modifications are possible within the scope of the claims. The technical scope of the present invention also includes embodiments obtained by appropriately combining the technical means disclosed in the embodiments. Furthermore, new technical features can be formed by combining the technical means disclosed in the embodiments. EXAMPLES

[0095] The present invention will be further described below with reference to examples and comparative examples, but the present invention is not limited thereto. In the following, % means % by weight, and parts means parts by weight, unless otherwise specified.

[0096] The various materials used in the examples and comparative examples are described below.

[0097] <Resin (A)> A1: Polyamide resin (produced based on the method described below in <Polyamide resin A1>) A2: Butyral resin (Kuraray Co., Ltd., "Mobital B75H") A3: Silicone resin (DOWSIL RSN-0255 Flake Resin, manufactured by Dow Toray Co., Ltd.) <Filler (B)> B1: Carbon black (manufactured by Denka Co., Ltd., "Denka Black", primary particle diameter: 48 nm, DBP oil absorption: 177 cm 3 / 100g) B2: Carbon black (manufactured by MTI Corporation, "Super C65", primary particle size: 50 nm, DBP oil absorption: 254 cm 3 / 100g) B3: Carbon nanotubes (Showa Denko K.K., "VGCF-H") B4: High silica zeolite (Tosoh Corporation, "HSZ-690HOA") <Surfactant (C)> C1: Amine salt of polyether phosphate ester (Disparlon DA-325, manufactured by Kusumoto Chemicals Co., Ltd.) <Solvent (D)> D1: N-methyl-2-pyrrolidone (boiling point: 202°C) D2: Butyl butyrate (boiling point: 165°C) D3: Diethylene glycol monobutyl ether (boiling point: 230°C) D4: N,N-dimethylformamide (boiling point: 153℃) D5: Diethylene glycol monobutyl ether acetate (boiling point: 247°C) D6: Methyl ethyl ketone (boiling point: 80°C) D7: Dibenzyl ether (boiling point: 297°C) D8: 1-decanol (boiling point: 232°C) <Additives (E)> E1: Silane coupling agent (manufactured by Shin-Etsu Chemical Co., Ltd., "KBE-13") Production Example 1 of Resin (A) is shown below.

[0098] Production Example 1-1 (Production of Polyester Resin P1) In a reaction vessel equipped with a stirrer, thermometer, heating / cooling device, nitrogen inlet tube, reflux tube, dehydration tube with a cock, and pressure reducing device, 58.2 parts of 12-hydroxystearic acid and 441.8 parts of ε-caprolactone were charged, and the temperature was raised to 140°C over 4 hours under a nitrogen atmosphere, and then the reaction was carried out for 2 hours, and the resin was taken out when the remaining amount of ε-caprolactone was 1% or less. The resin taken out was cooled to room temperature, and then crushed and granulated to obtain polyester resin P1. The number average molecular weight (Mn) of polyester resin P1 was 2600, and the acid value was 21.7 mg KOH / g.

[0099] <Method of measuring number average molecular weight (Mn) and weight average molecular weight (Mv)> The number average molecular weight (Mn) and the weight average molecular weight (Mv) were measured using gel permeation chromatography (GPC) (HLC-802A (manufactured by Tosoh Corporation)) under the following conditions. Columns: G4000PWXL (manufactured by Tosoh Corporation) and G5000PWXL (manufactured by Tosoh Corporation), two of which were arranged in series. Mobile phase: 20% acetonitrile (containing 50 mM lithium chloride) Flow rate: 0.8mL / min Column temperature: 40℃ Pump: L-6200 (manufactured by Hitachi, Ltd.) Detector: L-3300 (RI: differential refractometer, Hitachi, Ltd.) and L-4200 (UV-VIS: ultraviolet-visible spectrophotometer, Hitachi, Ltd.) Sample solution: 0.5% by weight acetonitrile solution Sample injection volume: 200 μL.

[0100] <Acid value measurement method> The acid value was measured according to the method specified in JIS K0070 (1992 edition).

[0101] Production Example 1-2 (Production of Polyamide Resin A1) Into a reaction vessel having the same configuration as the reaction vessel described in Production Example 1-1, 120 parts of xylene and 82.3 parts of a 20% aqueous solution of polyallylamine (manufactured by Nittobo Medical Co., Ltd., trade name "PAA-03", weight average molecular weight) were added, and the mixture was heated to 160°C while being sealed and stirred, and the distilled water was removed using a dehydrator with a cock. During this time, the xylene in the distillate was separated from the water and returned to the reaction vessel. Then, 83.5 parts of the xylene solution of polyester resin P1 obtained in Production Example 1-1 was added, and stirring was continued at 160°C for 3 hours. After 3 hours, the xylene was removed using a pressure reducing device, and polyamide resin A1 having an acid value of 14.9 mgKOH / g and a weight average molecular weight of 10,200 was obtained.

[0102] An example of producing a resin composition solution will be described below.

[0103] Production example 2 <Resin composition solution (S-1)> The following components were weighed in the following amounts into a sample bottle to obtain a mixture.

[0104] Resin A1 (polyamide resin) 30 parts by weight Filler B1 20 parts by weight Solvent D1 450 parts by weight The mixture was stirred at 2000 rpm for 20 minutes using a centrifugal / revolution mixer (ARE-310 manufactured by Thinky Corporation) to obtain a slurry, which was a resin composition solution (S-1).

[0105] Production examples 3 to 19 <Resin composition solution (S-2) to (S-18)> Resin compositions (S-2) to (S-18) were prepared in the same manner as for the resin composition solution (S-1), by weighing out the components into sample bottles based on the blending amounts shown in Table 1. When the surfactant (C1) or additive (E1) was used, it was weighed out into a sample bottle in the same manner as the other components.

[0106] The compositions and physical properties of the resin composition solutions are shown in Table 1.

[0107] [Table 1]

[0108] <Manufacture of sensor substrate K-1> [Manufacture of substrate] Figures 16 and 17 are schematic diagrams for explaining the manufacturing method of the sensor substrate K-1 used in the examples. In this example, a glass cloth-based epoxy resin copper-clad laminate FR-4.0 (manufactured by Panasonic Electric Works Co., Ltd.) having a length of 150 mm, a width of 100 mm, and a thickness of 1.0 mm was used, and sensor substrates (corresponding to the substrate 12 in the embodiment) designed on the laminate were manufactured in 16 rows vertically and 16 columns horizontally (a total of 256 substrates) by the method described below, as shown in Figures 16 and 17. At this time, 11 mm was secured on the top and bottom parts, and 10 mm was secured on the left and right parts as margins.

[0109] [Wiring pattern design] 18 and 19 are schematic diagrams showing the structure of the sensor substrate K-1 used as an example. Fig. 18 shows the front surface (the surface on which the metal wiring 16 and the odorant receiving layer 14 are arranged in Fig. 14) of the sensor element (corresponding to the odor sensor element 10 in the embodiment), and Fig. 19 shows the back surface (the surface opposite to the front surface) of the sensor element. As shown in Fig. 16, the substrate size is 8 mm long and 5 mm wide, and the T-shaped metal wirings (first metal wiring 16A and second metal wiring 16B) shown in Fig. 14 face each other. The lengths of the metal wirings 161A and 161C are 2.5 mm, the lengths of the metal wirings 161B and 161D are 2 mm, the distance between the metal wirings 161A and 161C is 1.5 mm, and the width of each metal wiring is 0.3 mm. A total of 256 wiring patterns were designed on the above-mentioned laminate. Furthermore, as shown in Figures 18 and 19, a circular conductive portion having a diameter of 1 mm was provided at the ends of the first metal wiring 16A and the second metal wiring 16B that do not face each other, as a portion for inserting a pin, which is a conductive member for electrically connecting to other components of the odor sensor, and a similar circular conductive portion having a diameter of 1 mm was designed at the same position on the back surface.

[0110] [Through-hole manufacturing process] In order to mount a pin (corresponding to pin 22 in the embodiment) on each sensor board, a through-hole was drilled in a circular conductive portion with a diameter of 1 mm using an NC drill machine, and first electroless copper plating and then copper sulfate plating were applied to create a through-hole with a copper plating layer of 25 μm in thickness.

[0111] [Pattern Forming Process] A photosensitive dry film resist (product name "Photec RD-3025", film thickness 25 μm, manufactured by Showa Denko Materials Co., Ltd.) was attached to both sides of the sensor substrate using a roll laminator (pressure 0.4 MPa, temperature 110°C, lamination speed 0.4 m / min). After that, ultraviolet light (wavelength 355 nm) was applied at 85 mJ / cm2 from the photosensitive dry film resist side through a negative photomask for the front side and a negative photomask for the back side in an ultraviolet exposure machine. 2The photosensitive dry film resist in the unexposed areas was removed with a 5 wt % aqueous solution of sodium carbonate at 35° C. Thereafter, the copper foil in the exposed areas where the photosensitive dry film resist had been removed was removed by etching using an aqueous solution of ferric chloride, and the photosensitive dry film resist in the exposed areas was removed using a 10 wt % aqueous solution of sodium hydroxide at 35° C.

[0112] The negative photomask for the front side used had a pattern in which the designed sensor substrate was arranged in 16 rows spaced 8 mm apart vertically and 16 columns spaced 5 mm apart horizontally, while the negative photomask for the back side had a pattern in which circles with a diameter of 1 mm were arranged in positions that coincided with the circular parts of the negative photomask for the front side.

[0113] [Solder resist process] A two-component alkaline development type solder resist ink (manufactured by Taiyo Ink Mfg. Co., Ltd., product name "PSR-4000 AUS320 / CA-40 AUS320") was pattern-printed on the front side except for the copper foil, through-holes, and strip-shaped odorant receiving layer 14 (shown with diagonal lines in FIG. 18), and on the back side except for the copper foil and through-holes. The ink was then heated at 80°C for 30 minutes to dry temporarily, and then exposed to ultraviolet light (wavelength 355 nm) at 600 mJ / cm. 2 The unexposed areas were then removed with a 1% by weight aqueous solution of sodium carbonate at 35°C. The solder resist ink was then cured by heating at 150°C for 60 minutes. The solder resist formed on the sensor substrate can regulate the wetting and spreading of the resin composition solution that is applied in a later process.

[0114] [Surface treatment process] The sensor substrate was degreased, soft etched, and acid washed, then immersed in a catalyst application solution (manufactured by Okuno Chemical Industries Co., Ltd., product name "ICP Accela COA") at 25°C for 5 minutes, rinsed with water, and immersed in an electroless Ni plating solution (manufactured by Okuno Chemical Industries Co., Ltd., product name "TOP NICORON SA-98-MLF" 100 ml and "TOP NICORON SA-98-1LF" 55 ml) at 90°C for 6 minutes to form a Ni coating with a thickness of 3 μm, and then washed with pure water.

[0115] Next, the sensor substrate was immersed in a displacement gold plating solution (manufactured by Kojima Chemical Industries, Ltd., product name "OL 2300") at 85°C for 5 minutes to form a displacement gold coating of 0.05 μm thickness on the Ni coating, resulting in a substrate in which the copper foil portion was covered with nickel and gold plating.

[0116] [V cut on the circuit board] Using a V-cutting machine, V-cuts were made every 8 mm in length and 5 mm in width so that each sensor board could be separated.

[0117] [Pin mounting] An IC terminal (manufactured by Mac Eight Corporation, product name "Hybrid IC Terminal", φ0.6 mm, length 5 mm) was soldered to the fabricated through-hole. In this way, a total of 256 sensor boards K-1 shown in Fig. 18 and Fig. 19 were fabricated.

[0118] <Sensor element> Example 1 Using a 1μPIPETMASTER manufactured by Musashi Engineering Co., Ltd., a Violamo Sakura tip (volume 10μL, material polypropylene. Dedicated rack storage item) manufactured by Violamo was attached, and 10μL of the resin composition solution (S-1) was sucked from the container storing the resin composition solution (S-1). After the pipette tip after the aspirating was attached to the edge of the container to drain the liquid, 0.1μL of the resin composition solution (S-1) was discharged onto the sensor substrate K-1 prepared, thereby applying it to the metal wiring part. After application, the resin composition solution (S-1) was dried for 3 hours in a circulating dryer heated to 100°C, and after drying, it was cooled to room temperature to prepare a sensor element (E1-1). The above-mentioned operations after the discharge process were performed 10 times in succession to prepare 10 sensor elements (E1-1).

[0119] Examples 2 to 27, Comparative Examples 2 and 3 Based on the discharge amount and continuous discharge number shown in Table 2, the same operation as in Example 1 was performed to prepare 10 each of sensor elements (E1-2) to (E1-27) and (E'1-2) to (E'1-3). For those with less than 10 continuous discharge numbers, after discharging the number of continuous discharges, the Viola Mosakura chip was discarded and a new Viola Mosakura chip was attached, and the inhalation process, discharge process, and drying process described in Example 1 were performed.

[0120] Examples 28 to 54, Comparative Examples 6 and 7 Based on the resin composition solution, discharge amount, and number of continuous discharges described in the odorant receiving layer column of Table 3, the same operation as in Example 1 was performed to prepare 10 sensor elements each having an odorant receiving layer. After that, the used Viola Mosakura chip was discarded, a new Viola Mosakura chip was attached, and based on the resin composition solution, discharge amount, and number of continuous discharges described in the odorant permeation layer column of Table 3, the same operation as in Example 1 was performed to prepare 10 sensor elements each having an odorant permeation layer (E2-1) to (E2-27), (E'2-3) to (E'2-4).

[0121] Comparative Example 1 The resin composition solution (S-1) was poured into a syringe equipped with a SUS metal needle nozzle (inner diameter 0.1 mmΦ, outer diameter 0.23 mm), and the plunger was pushed in to remove trapped air, and then the syringe was attached to IMAGE MASTER350PCSmart manufactured by Musashi Engineering Co., Ltd. Using this, 0.1 μL of the resin composition solution (S-1) was dispensed onto the prepared sensor substrate K-1, thereby applying it to the metal wiring portion. After application, the substrate was dried for 3 hours in a circulating air dryer heated to 100°C. After drying, the substrate was cooled to room temperature to prepare a sensor element (E'1-1). The same operation was repeated 10 times to prepare 10 sensor elements (E'1-1).

[0122] Comparative Examples 4 and 5 Based on the resin composition solution, discharge amount, and number of continuous discharges listed in the odorant receptive layer column of Table 3, the same operation as in Comparative Example 1 was performed to prepare 10 sensor elements each having an odorant receptive layer. Then, using a syringe different from the syringe used, based on the resin composition solution, discharge amount, and number of continuous discharges listed in the odorant permeable layer column of Table 2, the same operation as in Comparative Example 1 was performed to prepare 10 sensor elements each having an odorant permeable layer (E'2-1) to (E'2-2).

[0123] <Construction of an odor sensor> We created a housing equipped with a target sample receiving section equipped with an inlet for introducing the sample (odor substance) and an aluminum block thermostatic bath for temperature control, a nitrogen gas cylinder for gas supply, a mass flow controller, and a sensor chamber. At this time, the volume of the target sample receiving section was designed to be five times the volume of the sensor chamber.

[0124] The lead wires for taking out the sensor terminals to the outside were soldered to each of the sensor elements (E1-1) to (E1-27), (E2-1) to (E2-27), (E'1-1) to (E'1-3), and (E'2-1) to (E'2-4) to be evaluated, and then placed in the sensor chamber. A 5V constant voltage power supply and a 300Ω fixed resistor were connected in series to the end of the lead wires taken out of the sensor chamber for each of the sensor elements (E1-1) to (E1-27), (E2-1) to (E2-27), (E'1-1) to (E'1-3), and (E'2-1) to (E'2-4), and a voltmeter was connected to measure the voltage across both terminals of the sensor element. In this way, multiple odor sensors were constructed having the sensor elements (E1-1) to (E1-27), (E2-1) to (E2-27) and the comparative sensor elements (E'1-1) to (E'1-3), (E'2-1) to (E'2-4). The correspondence between the odor sensor numbers and the sensor element numbers of the odor sensors is as shown in Tables 2 and 3.

[0125] 〔evaluation〕 <Measurement of voltage change (ΔV) when measuring ion-exchanged water> Each of the odor sensors 1 to 54 and c1 to c7 was installed in a laboratory (temperature 25°C, humidity 50%), and the temperature inside the target sample receiving section was adjusted to 30°C using an aluminum block thermostatic bath, and 5 ml of ion-exchanged water was placed in the target sample receiving section as a specimen. After that, nitrogen as a carrier gas was flowed from the carrier gas inlet section into the chamber in which the sensor element was installed at a flow rate of 1 L / min using a gas flow regulator, and discharged to the outside. During this time, the measured value of the voltmeter connected to the sensor element was recorded by a computer. In this way, the voltage value of each of the 10 sensor elements in the odor sensor was measured. For each sensor element of each odor sensor, the maximum value ΔV (water) of the difference between the output voltage V0 before the introduction of the sample and the voltage V after the introduction of the sample was calculated. Then, the average value μ (water) of the 10 maximum value ΔV data obtained for each odor sensor was calculated.

[0126] <Measurement of voltage change (ΔV) and ΔV variation coefficient in ethanol measurement> The ΔV (ethanol) and average value μ (ethanol) were calculated using the same method except that ethanol was used instead of ion-exchanged water as the sample. Furthermore, the standard deviation σ (ethanol) of ΔV (ethanol) was calculated, and the ΔV variation coefficient (=σ / μ) of each sensor element was obtained.

[0127] <Measurement of voltage change (ΔV) in hexane measurement> The same procedure was followed except that hexane was used as the sample instead of ion-exchanged water, and ΔV (hexane) and the average value μ (hexane) were calculated.

[0128] <Ratio of voltage change (ΔV)> The voltage change (ΔV) when ion-exchanged water, ethanol, and hexane were measured as samples was divided by the voltage change (ΔV) of ion-exchanged water for each sensor element to calculate the ratio of the voltage changes (ΔV).

[0129] Table 2 shows the shape of the dispenser, the type of resin composition solution, and the discharge amount used for odor sensors 1 to 27 of Examples 1 to 27 and odor sensors c1 to c3 of Comparative Examples 1 to 3.

[0130] [Table 2]

[0131] Table 3 shows the shape of the dispenser, the type of resin composition solution, and the discharge amount for each of odor sensors 28 to 54 of Examples 28 to 54 and odor sensors c4 to c7 of Comparative Examples 4 to 7.

[0132] [Table 3]

[0133] In Tables 2 and 3, the ratio of ΔV for each sample is preferably as large as the difference between the three values ​​from the viewpoint of the sensitivity of the odor sensor, whereas the smaller the ΔV coefficient of variation, the more preferable it is from the viewpoint of reducing the variability.

[0134] <Consideration> As shown in Tables 2 and 3, odor sensors 1 to 54 all exhibit a larger difference in ΔV ratio and a lower ΔV variation coefficient than the comparative odor sensors c1 to c7.

[0135] Comparing Examples 1 to 54 with Comparative Examples 1, 4, and 5, it was found that odor sensors c1, c4, and c5, which have odorant receptive layers or odorant permeable layers manufactured by methods that do not use a pipette-type dispenser, had small differences in the ΔV ratios and large ΔV variation coefficients.

[0136] Comparing Examples 1 to 54 with Comparative Examples 2, 3, 6, and 7, it was found that odor sensors c2, c3, c6, and c7, which have odorant receptive layers or odorant permeable layers manufactured using methods with ejection volumes of less than 0.1 μL or more than 5.0 μL, had small differences in the ΔV ratios and large ΔV variation coefficients.

[0137] Comparing Examples 5, 9 to 19, 28, and 32 to 42, it was found that ΔV ratios and ΔV variation coefficients that were acceptable for practical use were obtained regardless of the viscosity of the resin composition solution or the boiling point of the organic solvent. In particular, odor sensor 5, which was equipped with a sensor element manufactured using a resin composition solution with a viscosity of 8 mPa s and a boiling point of an organic solvent of 202°C, had the largest difference in ΔV ratio and the smallest ΔV variation coefficient.

[0138] Comparing Examples 5, 11, 12, 19, 28, 34, 35, and 42, it was found that ΔV ratios and ΔV variation coefficients that were practically acceptable were obtained regardless of the solid content of the resin composition solution. In particular, odor sensor 5, which was equipped with a sensor element manufactured using a resin composition solution with a solid content of 10%, had the largest difference in ΔV ratio and the smallest ΔV variation coefficient.

[0139] Comparison of Examples 5, 11, 12, 19, 28, 34, 35, and 42 shows that ΔV ratios and ΔV variation coefficients that are practically acceptable are obtained regardless of the thixotropic index of the resin composition solution. In particular, odor sensor 5, which is equipped with a sensor element manufactured using a resin composition solution with a thixotropic index of 1.1, had the largest difference in ΔV ratio and the smallest ΔV variation coefficient.

[0140] Comparing Examples 5 and 25, or 28 and 48, and comparing Examples 12, 20, and 21, it is found that ΔV ratios and ΔV variation coefficients that are practically acceptable are obtained, even when a filler is present or the type of filler is different.

[0141] Therefore, it was found that the odor sensor element manufactured by the manufacturing method including the steps of: using a pipette-type dispenser equipped with a removable nozzle at the tip, sucking the resin composition solution containing an organic solvent from a container storing the resin composition solution into the nozzle; discharging the resin composition solution from the nozzle and applying it onto the substrate after the suction step to form a coating film on the substrate; and drying the coating film to form the sensitive film after the coating step, in which the amount of the resin composition solution discharged from the nozzle is 0.1 μL to 5.0 μL, exhibits a ΔV ratio and a ΔV variation coefficient that are practically acceptable. In other words, an odor measuring device equipped with such an odor sensor has high odor detection sensitivity and can output stable measurement results, and therefore has high odor identification performance. [Explanation of symbols]

[0142] 10. Odor sensor element 12 Substrate 14 Odor receptor layer (sensing membrane) 16 Metal wiring 18 Lead Wire 20 Odorant permeable layer (sensing membrane) 22 Container 24 Pipette-type dispenser 26 Pipettes 28 Nozzles 30 containers 32 Odor Sensor 34 Case 34i inlet 34e outlet 36 Material receiving section (anteroom) 38 Constant voltage power supply (power supply) 40 Voltmeter L1 resin composition solution F1 Coating L2 resin composition solution F2 coating

Claims

1. A method for manufacturing a sensitive film of an odor sensor element on a substrate, comprising the steps of: a suction step of sucking a resin composition solution containing an organic solvent from a container storing the resin composition solution into the nozzle using a pipette-type dispenser having a detachable nozzle at the tip; a coating step of discharging the resin composition solution from the nozzle and coating the resin composition solution on the substrate after the suction step is completed, thereby forming a coating film on the substrate; A drying step of drying the coating film to form the sensitive film after the coating step is completed, The method for manufacturing a sensitive film of an odor sensor element, wherein the amount of the resin composition solution discharged from the nozzle is 0.1 μL to 5.0 μL.

2. 2. The method for manufacturing a sensitive film of an odor sensor element according to claim 1, wherein the viscosity of the resin composition solution is 1 mPa·s to 500 mPa·s, and the boiling point of the organic solvent is 150°C to 250°C.

3. 2. The method for manufacturing a sensitive film of an odor sensor element according to claim 1, wherein the solid content of the resin composition solution is 2% to 20%.

4. 2. The method for producing a sensitive film of an odor sensor element according to claim 1, wherein the thixotropic index of the resin composition solution measured with a rheometer is 1.05 to 5.

00.

5. The method for producing a sensitive film of an odor sensor element according to claim 1 , wherein the resin composition solution contains a filler.

6. The method for manufacturing a sensitive film of an odor sensor element according to claim 5 , wherein the filler is a conductive material.

7. The method for manufacturing a sensitive film of an odor sensor element according to claim 6, wherein the conductive material is a conductive carbon material.

8. The method for manufacturing a sensitive film of an odor sensor element according to claim 1 , further comprising a replacing step of replacing the nozzle every time the coating step is performed a predetermined number of times.

9. 2. The method for manufacturing a sensitive film of an odor sensor element according to claim 1, wherein the odor sensor element is a chemiresistor type odor sensor element that uses a change in the electrical resistance value of the sensitive film as an indicator for detecting odor.

10. A sensitive film of an odor sensor element, produced by the method for producing a sensitive film of an odor sensor element according to any one of claims 1 to 9.

11. A substrate; An odor sensor element comprising: a sensitive film manufactured on the substrate by the method for manufacturing a sensitive film of an odor sensor element according to claim 1 .

12. The odor sensor element according to claim 11 , wherein the sensitive film is an odorant-receiving layer.

13. The odor sensor element according to claim 11 , wherein the sensitive film is an odorant-permeable layer.

14. An odor sensor comprising the odor sensor element according to claim 11.

Images