Detection body, method for detecting gas, and detection device

Abstract

To provide a detection body that can shorten reaction time even when the concentration of gas is low.SOLUTION: A detection body has a pigment layer. The pigment layer has a chromic pigment and hydrophilic resin. The thickness of the pigment layer is 0.1 μm or more and 1 μm or less.SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to a detector capable of detecting a specific gas, such as a biological gas such as ammonia, a gas detection method, and a detection device.

Background Art

[0002] Various biological gases are emitted from the human body. The representative of biological gases is exhaled breath, but gas (referred to as "skin gas") is also emitted from the skin. Skin gas is generated by metabolism, the action of resident bacteria, etc. It is considered that metabolites volatilize directly from the blood or are emitted via sweat glands from the blood. Therefore, detection and analysis of skin gas may be used for diagnosing health conditions, leading to early detection of harmful substances, or used for judging the indoor air environment. For example, it is known that ammonia volatilizes from the skin when fatigue has accumulated or stress is felt. If ammonia emitted from the skin can be detected, the degree of fatigue and stress can be measured.

[0003] Conventionally, in order to detect trace amounts of skin gas, it has been necessary to use GC-MS, a concentration device, etc., so there have been problems such as being unable to measure on-site or taking a long time for analysis. Recently, as a detection means for solving such problems, a gas detection sheet using a chromic dye has been proposed. A chromic dye is a dye whose color changes reversibly by an externally applied stimulus. A gas detection sheet having a dye layer in which this chromic dye is dispersed in a matrix resin has been proposed.

[0004] For example, Patent Document 1 discloses a gas detection sheet provided with a gas detection unit whose color development or optical density changes when a gas to be detected comes into contact, and discloses using methyl red that reacts with a weakly acidic gas and metanil yellow that reacts with a strongly acidic gas as reactants for the gas detection unit. Patent Document 2 discloses a method for detecting ammonia gas using a gas detection sheet carrying a pH sensing material such as bromophenol blue.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0006] When using a detector for detecting biological gases, it has been an important issue to shorten the time required for detection (also referred to as "detection time"). However, since biological gases have a low concentration, shortening the detection time even at a low gas concentration has not been an easily solvable problem. Therefore, an object of the present invention is to provide a new detector, a gas detection method, and a detection device that can shorten the detection time even at a low gas concentration.

Means for Solving the Problems

[0007] The detector, gas detection method, and detection device proposed by the present invention have the following configurations in order to solve the above problems.

[0008] [1] The first aspect of the present invention is a detector having a dye layer, the dye layer having a chromic dye and a hydrophilic resin, and the thickness of the dye layer being 0.1 μm or more and 1 μm or less.

[0009] [2] The second aspect of the present invention is the detector according to the first aspect, wherein the dye is a pH-sensitive dye.

[0010] [3] A third aspect of the present invention is a detection body in which, in the first or second aspect, the hydrophilic resin has a polar group. [4] A fourth aspect of the present invention is a detection body in which, in any one of the first to third aspects, the hydrophilic resin is one or a combination of two or more selected from polyvinyl alcohol, polyvinyl pyrrolidone, polyethyleneimine, polyacrylic acid, sodium polyacrylate, poly(4-styrenesulfonic acid), poly(4-styrenesulfonic acid sodium), polyethylene oxide, water-soluble cellulose ether, and polyallylamine hydrochloride.

[0011] [5] A fifth aspect of the present invention is a detection body in which, in any one of the first to fourth aspects, it further has a substrate layer. [6] A sixth aspect of the present invention is a detection body in which, in any one of the first to fifth aspects, it further has a protective layer. [7] A seventh aspect of the present invention is a detection body in which, in the sixth aspect, the protective layer has a free volume radius of 0.35 nm or more and 1 nm or less. [8] An eighth aspect of the present invention is a detection body in which, in the sixth or seventh aspect, the protective layer contains silicone. [9] A ninth aspect of the present invention is a detection body in which, in any one of the sixth to eighth aspects, the thickness ratio of the protective layer to the dye layer (protective layer / dye layer) is 1 or more and 100 or less.

[0012]

[10] A tenth aspect of the present invention is a detection body in which, in any one of the first to ninth aspects, the detection substance is a basic gas.

[11] An eleventh aspect of the present invention is a detection body in which, in any one of the first to tenth aspects, the detection substance is a biological gas.

[0013]

[12] A twelfth aspect of the present invention is a gas detection method characterized by using the detection body of any one of the first to eleventh aspects.

[0014]

[13] The 13th aspect of the present invention is a detection device including the detection body according to any one of the 1st to 11th aspects.

[14] The 14th aspect of the present invention is the detection device according to the 13th aspect, which is a detection device (i.e., a wearable detection device) that is worn on a living body and used for detecting a biological gas.

[15] The 15th aspect of the present invention is the detection device according to the 14th aspect, which has the pigment layer and the protective layer, and the protective layer is disposed closer to the living body side than the pigment layer.

Advantages of the Invention

[0015] For the detection body, gas detection method, and detection device proposed by the present invention, since the pigment layer has a chromic dye and a hydrophilic resin, water-soluble gases such as ammonia gas can be dissolved and collected, and the gas can be detected by the color change due to the reaction between the chromic dye and the gas. Furthermore, by setting the thickness of the pigment layer to be 0.1 μm or more and 1 μm or less, the response time to the gas can be shortened, so that the detection time can be shortened even when the gas concentration is low.

Embodiments for Carrying Out the Invention

[0016] Hereinafter, an example of an embodiment of the present invention will be described. However, the present invention is not limited to the embodiments described below.

[0017] <<Detection Body of the Present Invention>> A detection body (referred to as "the detection body of the present invention") according to an example of an embodiment of the present invention has a pigment layer, and the pigment layer is characterized by containing a chromic dye and a hydrophilic resin.

[0018] The form of the detection body of the present invention is not particularly limited. For example, it may be in the form of a sheet or a tablet. Among them, from the perspective of processability, it is preferably in the form of a sheet.

[0019] Since the detection body of the present invention has the ability to collect gas in the dye layer, there is no need for a closed space to collect skin gas. Therefore, the degree of freedom in selecting the shape and form is significantly increased, and it is possible to respond to various designs. In addition, in the detection body of the present invention, since the hydrophilic resin also serves as the matrix resin of the dye layer, in other words, it also has the role of supporting the dye, unlike the case where the dye carrier is a fibrous filter, it is possible to make the dye layer transparent.

[0020] <Dye layer> The dye layer contains a chromic dye and a hydrophilic resin.

[0021] (Chromic dye) The chromic dye is a substance whose color changes reversibly by an external stimulus. Among them, a pH-sensitive dye (also referred to as a "pH-sensitive dye") is preferably used. For example, when a basic gas such as ammonia gas comes into contact with the dye layer and the dye layer shifts to basicity, the pH-sensitive dye changes color, and thus the gas can be detected. In addition, the generation of skin gas and the like can be detected by the color change of the chromic dye or the dye layer. Furthermore, it is also possible to quantify the concentration of the detected gas by the amount of color tone change of the chromic dye or the dye layer.

[0022] Examples of such pH-sensitive chromic dyes include, for example, metacresol purple, fluoran derivatives, crystal violet lactone, cresol red, phenol red, bromocresol purple, neutral red, bromothymol blue, naphthol phthalein, bromophenol blue, congo red, methyl orange, phenolphthalein, methyl red, alizarin yellow, thymol phthalein, cresol phthalein, neutral red, litmus, bromocresol green, thymol blue, malachite green, methyl violet red, etc. However, it is not limited to these. The type of dye is preferably appropriately selected according to the type of gas to be detected.

[0023] From the perspective of color development, the content of the chromic dye in the dye layer is preferably 1 part by mass or more, more preferably 5 parts by mass or more, and even more preferably 10 parts by mass or more with respect to 100 parts by mass of the hydrophilic resin in the dye layer. On the other hand, from the perspective of the solubility of the dye, it is preferably 35 parts by mass or less, more preferably 25 parts by mass or less, and even more preferably 15 parts by mass or less.

[0024] (Hydrophilic resin) From the perspective of ensuring water retention, the hydrophilic resin preferably has a polar group, particularly a water-soluble polar group. For example, resins having water-soluble polar groups such as a hydroxy group (hydroxyl group), an ether group, an amide group, a carboxyl group, a sulfone group, a sulfate ester group, a phosphate ester group, an amino group, an imino group, a tertiary amine group, a quaternary ammonium base, and a hydrazino group can be mentioned. However, it is not limited to these. The weight average molecular weight (Mw) of the hydrophilic resin is not particularly limited, but is, for example, 100 to 3,000,000.

[0025] Specific examples of the hydrophilic resin include, for example, polyvinyl alcohol, polyvinyl pyrrolidone, polyethyleneimine, polyacrylic acid, sodium polyacrylate, poly(4-styrenesulfonic acid), sodium poly(4-styrenesulfonate), polyethylene oxide, water-soluble cellulose ether, and polyallylamine hydrochloride. These hydrophilic resins can be used alone or in combination of two or more of them. However, the hydrophilic resin is not limited to these.

[0026] Among these, as the hydrophilic resin that functions as a matrix for the pH-sensitive dye, a hydrophilic resin with higher water retention is preferred. If it is a hydrophilic resin with higher water retention, the water retention of the dye layer can be further enhanced, and the water in the dye layer can capture water-soluble gas. Therefore, even a gas with a lower concentration can react and cause color change. From this perspective, polyvinyl alcohol, polyvinyl pyrrolidone, etc. are preferred. Examples of the water-soluble gas include, for example, chlorine, ammonia, hydrogen chloride, sulfur dioxide, hydrogen sulfide, hydrofluoric acid, etc.

[0027] Also, from the perspective that a hydrophilic resin with higher water retention is preferred, the proportion of hydrophilic polar groups in the hydrophilic resin is preferably 60 mol% or more, more preferably 70 mol% or more, and even more preferably 80 mol% or more from the perspective of enhancing water retention. On the other hand, it is preferably 99 mol% or less, more preferably 95 mol% or less, and even more preferably 90 mol% or less.

[0028] When using polyvinyl alcohol as the hydrophilic resin, its saponification degree is preferably 60% or more, more preferably 70% or more, and even more preferably 80% or more from the perspective of ensuring the amount of OH groups and enhancing water retention. On the other hand, from the perspective of suppressing crystallinity and maintaining water retention, it is preferably 99% or less, more preferably 95% or less, and even more preferably 90% or less.

[0029] (pH adjuster) The dye layer can contain a pH adjuster as needed. For example, an acidic pH adjuster is incorporated into the dye layer to fix the hue layer in an acidic state. When a basic gas such as ammonia gas contacts the dye layer and the dye layer shifts to basic, the pH-sensitive dye changes color and the gas can be detected. However, it is not limited to the acidic pH adjuster for adjusting to the acidic side, and an alkaline pH adjuster for adjusting to the alkaline side may also be used.

[0030] Examples of acidic pH adjusters include citric acid, acetic acid, succinic acid, hydrochloric acid, etc. On the other hand, examples of alkaline pH adjusters include ammonia, ammonium carbonate, sodium carbonate, arginine, etc. However, the pH adjuster is not limited to these.

[0031] (Thickness of the pigment layer) For visually recognizing color change, it is preferable that the entire film changes color. When the thickness of the pigment layer is thinner, the rate of water retention and reaction is faster, and the response time, that is, the detection time, becomes shorter. On the other hand, if the pigment layer is too thin, the color development itself becomes weak and the color tone change cannot be recognized. Therefore, the thickness of the pigment layer is preferably 0.1 μm or more, more preferably 0.2 μm or more, and even more preferably 0.3 μm or more. On the other hand, it is preferably 1 μm or less, more preferably 0.8 μm or less, and even more preferably 0.6 μm or less.

[0032] <Substrate layer> Functions expected of the substrate layer include, for example, maintaining mechanical strength, protecting the pigment layer, serving as a carrier for the pigment layer, imparting selectivity to gas adsorption / diffusion, preventing light scattering, acting as an optical filter, or maintaining the detection characteristics (sensitivity, responsiveness) of the pigment. It is preferable that it has at least one of these functions.

[0033] Examples of the substrate layer include papers such as filter paper, fine paper, and coated paper, plastic sheets, non-woven fabrics, porous molded products, woven fabrics, and metal foils such as aluminum foil.

[0034] Among them, from the viewpoints of processability and transparency, a plastic sheet is preferable. Examples of the resin constituting the plastic sheet include acrylic resin, amino resin, chlorine-based resin, nylon, fluororesin, polyurethane, polyester, polyolefin, polycarbonate, polystyrene, cellulose resin, and the like. More specifically, polyethylene, polyethylene oxide, polypropylene, polysulfone, polyamide, polyether ether ketone (PEEK), polyarylate, polyaramide, polyether, polyaryl ether, polyimide, polyetherimide, polyphthalamide, polyester, polyacrylate, polymethacrylate, cellulose acetate, water-soluble cellulose ether, polycarbonate, polyacrylonitrile, polytetrafluoroethylene and other fluorinated polymers, polyvinyl alcohol, polyvinyl pyrrolidone, polyvinyl acetate, syndiotactic or amorphous polystyrene, liquid crystal polymer, epoxy resin, phenol resin, polydimethylsiloxane elastomer, silicone resin, fluorosilicone elastomer, fluorosilicone resin, polyurethane, cellulose ester, and copolymers, mixtures, or derivatives thereof can be mentioned. However, it is not limited thereto.

[0035] Considering that the detection body of the present invention is worn on the human body and visually recognizes color change, etc., the base material layer is preferably transparent and flexible. From such a viewpoint, the base material layer is preferably made of polyethylene, polypropylene, polyester, polyacrylate, polycarbonate, etc. among the above.

[0036] From the viewpoint of handleability, the thickness of the base material layer is preferably 5 μm or more, more preferably 10 μm or more, and still more preferably 20 μm or more. On the other hand, from the viewpoint of flexibility, it is preferably 50 μm or less, more preferably 40 μm or less, and still more preferably 30 μm or less.

[0037] <Protective layer> For the purpose of preventing elution and detachment of the pigment, preventing discoloration due to adhesion of water droplets such as sweat, or preventing discoloration under high humidity, it is preferable to provide a protective layer on the pigment layer.

[0038] From the viewpoint of allowing not only gas but also water vapor to permeate so as not to inhibit the hygroscopicity of the pigment layer and reduce the reactivity and reaction time, the free volume radius of the protective layer is preferably 0.35 nm or more and 1 nm or less. If the free volume radius of the protective layer is 0.35 nm or more, it is easy to permeate the gas or water vapor to be detected, etc., so that the gas responsiveness of the detection sheet of the present invention can be enhanced. From such a viewpoint, the free volume radius of the protective layer is more preferably 0.35 nm or more, still more preferably 0.40 nm or more, and even more preferably 0.45 nm or more. On the other hand, if the free volume radius of the protective layer is 1 nm or less, elution and detachment of the pigment and discoloration due to adhesion of water droplets such as sweat can be prevented. From such a viewpoint, the free volume radius of the protective layer is more preferably 1 nm or less, still more preferably 0.8 nm or less, and even more preferably 0.6 nm or less. In addition, as long as the protective layer has a free volume radius within the above range, it may have a free volume radius outside the above range. Therefore, the protective layer may contain a resin other than the preferable resin described below. However, in that case, the other resin is preferably a resin that does not hinder the permeability of the gas or water vapor to be detected and has a content that does not hinder it.

[0039] In order to make the free volume radius of the protective layer within the above range, it is preferable to form the protective layer using a resin having a free volume radius of 0.35 nm or more and 1 nm or less. Preferable resins having a free volume radius of 0.35 nm or more and 1 nm or less include, for example, silicone, polyethylene, polypropylene, polystyrene, etc. Among them, from the viewpoint of achieving both gas and water vapor permeability and protection of the pigment layer, silicone (a liquid, rubbery, or resinous synthetic polymer compound having a main skeleton composed of a siloxane bond which is a bond between silicon and oxygen) is particularly preferable. By containing silicone in the protective layer, which has a large free volume radius and can be flexible, it is possible to prevent the elution and detachment of the dye and enhance the stability against the external environment without affecting the gas responsiveness. Further, it is desirable that the protective layer is transparent.

[0040] From the viewpoint of protecting the dye layer, the thickness of the protective layer is preferably 0.1 μm or more, more preferably 0.3 μm or more, and still more preferably 0.5 μm or more. On the other hand, in order not to inhibit the hygroscopicity of the dye layer and reduce the reactivity and reaction time, it is preferably 20 μm or less, more preferably 15 μm or less, still more preferably 10 μm or less, further preferably 5 μm or less, still more preferably 3 μm or less, and particularly preferably 1 μm or less.

[0041] (Other components) Each layer constituting the detection body of the present invention may contain other components in addition to the above-mentioned contained components, if necessary. Examples of other components include surfactants, emulsifiers, dispersants, polymer stabilizers, crosslinking agents, gelling agents, wetting agents, humectants, defoaming agents, water retention agents, hygroscopic agents, color developers, fungicides, antibacterial agents, oils, plasticizers, catalysts useful for providing secondary polymerization or crosslinking of particles, rheology modifiers, density modifiers, aziridine stabilizers, curing modifiers such as hydroquinone and hindered amines, waxes, driers, pH buffers, reaction promoters such as catalysts and enzymes, reaction modifiers such as radical scavengers and reducing agents, free radical reaction initiators, diluents, acid acceptors, antioxidants, heat stabilizers, flame retardants, scavenging agents, silylating agents, foam stabilizers, solvents, diluents, hydrosilylation-reactive diluents, plasticizers, fillers and inorganic particles, pigments, dyes, and desiccants. Optionally, a liquid may be used.

[0042] <Laminated structure> The detection body of the present invention can be, for example, a structure in which a substrate layer and a dye layer are laminated, or a structure in which a substrate layer, a dye layer, and a protective layer are laminated. Among them, it is preferable to have a structure in which the substrate layer, the dye layer, and the protective layer are laminated in this order. However, even if other layers are interposed between the respective layers, it may be configured such that other layers are laminated outside the base material layer or the protective layer.

[0043] From the viewpoint of gas responsiveness, the thickness ratio (base material layer / dye layer) of the base material layer and the dye layer is preferably 10 or more, more preferably 25 or more, and still more preferably 50 or more. On the other hand, from the viewpoint of color developability, it is preferably 500 or less, more preferably 400 or less, and still more preferably 300 or less.

[0044] From the viewpoint of protecting the dye layer, the thickness ratio (protective layer / dye layer) of the protective layer and the dye layer is preferably 1 or more, more preferably 2 or more, and still more preferably 3 or more. On the other hand, in order not to inhibit the hygroscopicity of the dye layer and reduce the reactivity and reaction time, it is preferably 100 or less, more preferably 40 or less, still more preferably 30 or less, still more preferably 20 or less, and particularly preferably 10 or less.

[0045] <Method for manufacturing the detection body of the present invention> Next, an example of the method for manufacturing the detection body of the present invention will be described. However, it is not limited to this manufacturing method.

[0046] For example, a paint containing a dye and a hydrophilic resin is prepared, and this paint is applied to a base material layer and dried to form a dye layer, whereby the detection body of the present invention can be produced. Thus, since the detection body of the present invention can be produced only by applying a paint to a base material layer and drying it, it is possible to increase the area of the detection body of the present invention, and the manufacturing process can be shortened and the cost can be reduced.

[0047] More specifically, for example, a dye and a hydrophilic resin are added to an acidic aqueous solution to prepare a paint, and this paint is applied to a base material layer and dried to form a dye layer, whereby the detection body of the present invention can be produced. By manufacturing the detection body of the present invention in this way, the coating film, that is, the dye layer can be fixed in an acidic state, and the color of the dye can be fixed and contained as it is in the acidic state, so that the color of the dye layer can be fixed to that color. If the acid-fixed dye layer contains a pH-sensitive dye, when it comes into contact with a basic gas such as ammonia gas, it will shift to basicity, and in response to this, the dye layer will change color, so ammonia gas can be detected.

[0048] At this time, examples of the acidic aqueous solution include acetic acid aqueous solution, citric acid aqueous solution, succinic acid aqueous solution, hydrochloric acid, and the like. From the viewpoint of controlling the color development of the pH-sensitive dye, the pH of the acidic aqueous solution is preferably 2.0 to 4.0, more preferably 2.5 or more or 3.5 or less, and even more preferably 2.8 or more or 3.2 or less. From the viewpoint of controlling the color development of the pH-sensitive dye, the pH of the dye layer is preferably 2.0 to 4.0, more preferably 2.5 or more or 3.5 or less, and even more preferably 2.8 or more or 3.2 or less. Also, the blending ratio of the dye and the hydrophilic resin is as described above.

[0049] The above manufacturing method is the case where the chromic dye contained in the dye layer is a pH-sensitive dye that reacts to the change from acidic to basic. When the chromic dye is a pH-sensitive dye that reacts to the change from basic to acidic, a paint may be prepared by adding the dye and the hydrophilic resin to a basic aqueous solution, and the present invention detection body may be manufactured by applying this paint to the base material layer and drying it. In this case, acidic gas can be detected.

[0050] As a method for forming the protective layer, for example, a solution containing the resin for forming the protective layer may be applied to the dye layer and dried.

[0051] Examples of the above coating methods include bar coating, spray coating, brush coating, etc., and examples of printing methods include various methods such as letterpress printing, offset printing, gravure printing, flexographic printing, and screen printing.

[0052] In addition, the paint for forming the dye layer and the solution for forming the protective layer may contain other components as necessary. Examples of other components include, for example, surfactants, emulsifiers, dispersants, polymer stabilizers, crosslinking agents, gelling agents, wetting agents, humectants, defoamers, water retention agents, hygroscopic agents, developers, fungicides, antibacterial agents, oils, plasticizers, catalysts useful for providing secondary polymerization or crosslinking of particles, rheology modifiers, density modifiers, aziridine stabilizers, curing modifiers such as hydroquinone and hindered amines, waxes, driers, pH buffers, reaction promoters such as catalysts and enzymes, reaction modifiers such as radical scavengers and reducing agents, free radical reaction initiators, diluents, acid acceptors, antioxidants, heat stabilizers, flame retardants, scavenging agents, silylating agents, foam stabilizers, solvents, diluents, hydrosilylation-reactive diluents, plasticizers, fillers and inorganic particles, pigments, dyes, and desiccants. Optionally, a liquid may be used. Examples of liquids include water, organic solvents, any liquid organic compound, silicone fluids, organic oils, ionic fluids, and supercritical fluids. Other optional components include polyethers having at least one alkenyl group per molecule, thickeners, fillers, and inorganic particles, stabilizers, waxes or wax-like materials, silicones, organofunctional siloxanes, alkylmethylsiloxanes, siloxane resins, silicone rubbers, silicone carbinol fluids that can be optional components, water-soluble or water-dispersible silicone polyether compositions, silicone rubbers, hydrosilylation catalyst inhibitors, adhesion promoters, heat stabilizers, UV stabilizers, and flow regulators.

[0053] In addition, examples of the method for forming the protective layer include, in addition to the above coating method, a method of laminating a resin film for forming the protective layer to the dye layer.

[0054] <Utilization / Applications> The detection element of the present invention can detect a predetermined gas, such as a biological gas, and can constitute a detection device (also referred to as "the detection device of the present invention") equipped with the detection element of the present invention. Therefore, a gas detection method, particularly a biological gas detection method, can be implemented using the detection element of the present invention or the detection device of the present invention. At this time, the biological gas as the detection substance may be any gas generated in the human body or on the body surface. For example, exhaled gases such as carbon dioxide and carbon monoxide, intestinal gases such as methane, and skin gases such as ammonia can be mentioned. However, it is not limited to these.

[0055] Also, when the chromic dye contained in the dye layer of the detection element of the present invention is a pH-sensitive dye, the gas as the detection substance can include basic gases such as ammonia and trimethylamine. On the other hand, acidic gases such as acetic acid, hydrogen sulfide, and formic acid can be mentioned. However, it is not limited to these. For example, if the detection element of the present invention can sense ammonia volatilized from the skin, the degree of fatigue and stress can be measured.

[0056] (Gas detection device) A gas detection device (also referred to as "the gas detection device of the present invention"), which is an example of an embodiment of the present invention, is a device equipped with the detection element of the present invention. Here, the device is intended to include equipment, devices, terminals, etc.

[0057] The gas detection device of the present invention can detect biological gases including skin gases such as ammonia.

[0058] The gas detection device of the present invention can include, for example, a sheet structure in which a configuration that can be attached to a human body, such as an arm, is added to the detection element of the present invention. At this time, in order to detect the generation of biological gases such as skin gases, it is preferably configured to be attached so that the opposite side of the base material layer of the detection element of the present invention, that is, the dye layer or the protective layer side, is arranged on the biological side, that is, the skin side.

[0059] It is also possible to install a plurality of gas detection sheets with different detection gases in combination.

[0060] As an example of the gas detection device of the present invention, a configuration including the detection body of the present invention, a light source, a light receiving element, a CPU, a display driving circuit, and a display is provided. Light is irradiated from the light source, and the reflected light due to the coloring of the dye layer is captured by the light receiving element. A signal from the light receiving element is sent to the CPU, and a driving signal is sent from the CPU to the display driving circuit to display on the display that a gas has been detected. In the gas detection device of the present invention having such a configuration, the intensity of the reflected light captured by the light receiving element becomes a magnitude corresponding to the degree of coloring of the dye layer, and a signal of information regarding the color change is output from the light receiving element. When the signal output from the light receiving element is input to the CPU, a signal regarding the measurement concentration is sent to the comparison circuit together with which light receiving element the signal is output from. In the comparison circuit, the previously stored calibration curve is compared with this measurement concentration to obtain the concentration of the detected gas. The obtained concentration is sent to the CPU, and a driving signal is sent from the CPU to the display driving circuit to display the concentration of the detected gas on the display. In this way, by quantifying the amount of color change of the dye or the dye layer, it becomes possible to quantify the detected gas.

[0061] <Explanation of terms, etc.> In the present invention, when referring to "film", it includes "sheet", and when referring to "sheet", it includes "film". In the present invention, when described as "α~β" (α and β are arbitrary numbers), unless otherwise specified, it includes the meaning of "α or more and β or less" and also the meaning of "preferably larger than α" or "preferably smaller than β". Also, when it is described as "α or more" or "α ≦" (α is an arbitrary number), unless otherwise specified, it includes the meaning of "preferably larger than α", and when it is described as "β or less" or "≦β" (β is an arbitrary number), unless otherwise specified, it also includes the meaning of "preferably smaller than β".

Examples

[0062] Hereinafter, an example of an embodiment of the present invention will be described. However, the present invention is not limited to the embodiments described below.

[0063] [Example 1] [Preparation of acetic acid aqueous solution (A-0) with pH = 3.0] 0.33 g of acetic acid (manufactured by Nacalai Tesque, Inc.) was diluted with 100 g of ion-exchanged water, and the pH was confirmed with a calibrated pH meter. Acetic acid and ion-exchanged water were appropriately added and finely adjusted until the pH reached 3.0 ± 0.1.

[0064] [Preparation of dye-containing resin solution (A-1)] 0.07 g (10 mM) of bromophenol blue (manufactured by Wako Pure Chemical Industries, Ltd.) was added to 9.4 g of acetic acid aqueous solution (A-0) with pH = 3.0, and the mixture was heated and stirred at 90 °C for 5 minutes. Further, 0.5 g of polyvinyl alcohol (manufactured by Mitsubishi Chemical Corporation, GH-17R) with a saponification degree of 88% was added, and the mixture was heated and stirred at 90 °C for 60 minutes.

[0065] [Production of gas detection film] As the base material layer, a polyethylene terephthalate sheet with a thickness of 50 μm (manufactured by Mitsubishi Chemical Corporation, DIAFOIL T100-100) was used. The surface of this polyethylene terephthalate sheet was corona-treated under the output condition: 100 W·min / m 2 and the dye-containing resin solution (A-1) was bar-coated on the corona-treated surface so that the film thickness after drying would be 0.3 μm, and then heated and dried to produce a gas detection film (sample).

[0066] [Example 2] [Production of gas detection film] A gas sensing film (sample) was prepared in the same manner as in Example 1, except that the pigment-containing resin solution (A-1) was bar-coated so that the film thickness after drying would be 0.4 μm.

[0067] [Example 3] [Preparation of Pigment-Containing Resin Solution (A-2)] 0.07 g (10 mM) of bromophenol blue (manufactured by Wako Pure Chemical Industries, Ltd.) was added to 9.4 g of an acetic acid aqueous solution (A-0) with a pH of 3.0, and the mixture was heated and stirred at 90 °C for 5 minutes. Further, 0.5 g of polyvinyl alcohol (manufactured by Mitsubishi Chemical Corporation, N-300) with a saponification degree of 99% was added, and the mixture was heated and stirred at 90 °C for 60 minutes.

[0068] [Fabrication of Gas Sensing Film] A gas sensing film (sample) was prepared in the same manner as in Example 1, except that the pigment-containing resin solution (A-2) was used instead of the pigment-containing resin solution (A-1).

[0069] [Example 4] [Preparation of Pigment-Containing Resin Solution (A-3)] 0.07 g (10 mM) of bromophenol blue (manufactured by Wako Pure Chemical Industries, Ltd.) was added to 9.4 g of an acetic acid aqueous solution (A-0) with a pH of 3.0, and the mixture was heated and stirred at 90 °C for 5 minutes. Further, 0.5 g of polyvinyl alcohol (manufactured by Mitsubishi Chemical Corporation, KH-20) with a saponification degree of 80% was added, and the mixture was heated and stirred at 90 °C for 60 minutes.

[0070] [Fabrication of Gas Sensing Film] A gas sensing film (sample) was prepared in the same manner as in Example 1, except that the pigment-containing resin solution (A-3) was used instead of the pigment-containing resin solution (A-1).

[0071] [Example 5] [Preparation of Pigment-Containing Resin Solution (A-4)] 9.4 g of an acetic acid aqueous solution (A-0) with pH = 3.0 was added with 0.07 g (10 mM) of bromophenol blue (manufactured by Wako Pure Chemical Industries, Ltd.) and heated and stirred at 90 °C for 5 minutes. Further, 0.5 g of polyvinyl alcohol with a saponification degree of 73% (manufactured by Mitsubishi Chemical Corporation, NK-05R) was added, and the mixture was heated and stirred at 90 °C for 60 minutes.

[0072] <Preparation of Gas Detection Film> A gas detection film (sample) was prepared in the same manner as in Example 1, except that the dye-containing resin solution (A-4) was used instead of the dye-containing resin solution (A-1).

[0073] [Example 6] <Preparation of Dye-Containing Resin Solution (A-5)> 9.4 g of an acetic acid aqueous solution (A-0) with pH = 3.0 was added with 0.07 g (10 mM) of bromophenol blue (manufactured by Wako Pure Chemical Industries, Ltd.) and heated and stirred at 90 °C for 5 minutes. Further, 0.5 g of polyvinylpyrrolidone (manufactured by Daiichi Kogyo Seiyaku Co., Ltd., Kureha (registered trademark) k-90) was added, and the mixture was heated and stirred at 90 °C for 60 minutes.

[0074] <Preparation of Gas Detection Film> A gas detection film (sample) was prepared in the same manner as in Example 1, except that the dye-containing resin solution (A-5) was used instead of the dye-containing resin solution (A-1).

[0075] [Example 7] <Preparation of Dye-Containing Resin Solution (A-6)> 9.4 g of an acetic acid aqueous solution (A-0) with pH = 3.0 was added with 0.07 g (10 mM) of bromophenol blue (manufactured by Wako Pure Chemical Industries, Ltd.) and heated and stirred at 90 °C for 5 minutes. Further, 0.5 g of a water-soluble cellulose ether containing a methoxy group (manufactured by Shin-Etsu Chemical Co., Ltd., Methocel (registered trademark) SM-04) was added, and the mixture was heated and stirred at 90 °C for 60 minutes.

[0076] <Preparation of Gas Detection Film> A gas detection film (sample) was produced in the same manner as in Example 1, except that the pigment-containing resin solution (A-6) was used instead of the pigment-containing resin solution (A-1).

[0077] [Example 8] [Preparation of Pigment-Containing Resin Solution (A-7)] 0.07 g (10 mM) of bromophenol blue (manufactured by Wako Pure Chemical Industries, Ltd.) was added to 9.4 g of an acetic acid aqueous solution (A-0) with a pH of 3.0, and the mixture was heated and stirred at 90°C for 5 minutes. Further, 0.5 g of a water-soluble cellulose ether containing a methoxy group and a hydroxyethoxy group (manufactured by Shin-Etsu Chemical Co., Ltd., Methocel (registered trademark) SE-06) was added, and the mixture was heated and stirred at 90°C for 60 minutes.

[0078] [Preparation of Gas Detection Film] A gas detection film (sample) was produced in the same manner as in Example 1, except that the pigment-containing resin solution (A-7) was used instead of the pigment-containing resin solution (A-1).

[0079] [Example 9] [Preparation of Pigment-Containing Resin Solution (A-8)] 0.07 g (10 mM) of bromophenol blue (manufactured by Wako Pure Chemical Industries, Ltd.) was added to 9.4 g of an acetic acid aqueous solution (A-0) with a pH of 3.0, and the mixture was heated and stirred at 90°C for 5 minutes. Further, 0.5 g of polyethylene oxide (manufactured by Meisei Chemical Industry Co., Ltd., Alcox R-150) was added, and the mixture was heated and stirred at 90°C for 60 minutes.

[0080] [Preparation of Gas Detection Film] A gas detection film (sample) was produced in the same manner as in Example 1, except that the pigment-containing resin solution (A-8) was used instead of the pigment-containing resin solution (A-1).

[0081] [Comparative Example 1] [Preparation of Gas Detection Film] A gas detection film (sample) was produced in the same manner as in Example 1, except that the pigment-containing resin solution (A-1) was bar-coated so that the film thickness after drying was 1.9 μm.

[0082] [Evaluation] For Examples 1 to 9 and Comparative Example 1, the measurement methods of the physical properties of each layer and the evaluation method of the gas detection film (sample) will be described.

[0083] (Film Thickness Measurement) The film thickness of each layer was measured using a high-precision micrometer (manufactured by Mitutoyo Corporation, MDH-25MB).

[0084] (Dilute Ammonia Exposure Test) On the inner wall of a 500 mL glass bottle, the substrate layer side of a gas detection film (sample) with an area of 100 cm × 40 cm was attached, and a Kimwipe moistened with water was placed at the bottom of the glass bottle. Dilute ammonia gas with a concentration adjusted to 2 ppm was allowed to flow into the glass bottle at a flow rate of 0.5 L / min for 10 minutes. For the measurement of ammonia concentration, a gas detection tube No. 3L (manufactured by Gastec Corporation) was used.

[0085] The color (ΔL * , Δa * , Δb * ) of the gas detection film (sample) before and after the dilute ammonia exposure test was measured using a color difference meter (manufactured by Nippon Denshoku Industries Co., Ltd., SD-6000). The response amount due to ammonia detection was quantified by the color tone change amount ΔX. ΔX = ((ΔL * ) 2 + (Δa * ) 2 + (Δb * ) 2 ) 1 / 2 ···(1) ΔL * : The change amount of the L * value before and after exposure to dilute ammonia Δa * : The change amount of the a * value before and after exposure to dilute ammonia Δb * : The change amount of the b * value before and after exposure to dilute ammonia

[0086] ΔX: Color tone change amount: The larger, the better. L * : Brightness. The larger the numerical value, the brighter; the smaller the numerical value, the darker. Values of a*, b*: Hue such as red or blue. When a* increases in the positive direction, red color becomes stronger; when it increases in the negative direction, green color becomes stronger. When b* increases in the positive direction, yellow color becomes stronger; when it increases in the negative direction, blue color becomes stronger.

[0087]

Table 1

[0088]

Table 2

[0089] In the dilute ammonia exposure test, for the gas sensing films (samples) prepared in Examples 1 to 9, in the use environment, that is, inside a glass bottle, the dye layer of the gas sensing film (sample) absorbs moisture, and ammonia gas dissolves in the moisture, so that the dilute gas is collected in the dye layer and discolored in response. It is considered that the degree of discoloration (color development) of the dye layer can be quantified by measuring with a color difference meter, and the amount of ammonia gas, that is, the detected gas, can be quantified numerically. For the gas sensing films (samples) prepared in Examples 1 to 9, discoloration could be confirmed within 10 minutes after contact with ammonia, while for the gas sensing film (sample) prepared in Comparative Example 1, discoloration could not be confirmed within 10 minutes after contact with ammonia.

[0090] From the above Examples, Comparative Examples, and the tests conducted by the present inventor so far, it was confirmed that when the dye layer contains a chromic dye and a hydrophilic resin, water-soluble gases such as ammonia gas can be dissolved and collected, and the gas can be detected by the color change due to the reaction between the chromic dye and the gas. It was found that if the thickness of the pigment layer is thin, the rate at which the entire gas detection film retains water is high, and as a result, the detection time is shortened. On the other hand, it was also found that if the thickness of the pigment layer is too thin, the color development of the pigment becomes weak and the color tone change cannot be recognized. From this, it can be considered that the thickness of the pigment layer is appropriately 0.1 μm or more and 1 μm or less.

[0091] Furthermore, when polyvinyl alcohol is used as the hydrophilic resin, if the saponification degree is too low, the amount of OH groups is small, resulting in a decrease in water retention and a tendency for the detection time to become long. Also, if the saponification degree is too high, the crystallinity increases, the water retention decreases, and the detection time tends to become long.

[0092] [Example 10] [Preparation of silicone solution (B-1)] 5 g of Agent A and 5 g of Agent B of liquid silicone (manufactured by Momentive, Silopren LSR 2650) were mixed and stirred for 5 minutes. Further, 40 g of toluene was added and dissolved. Degassing was performed by applying ultrasonic waves for 30 minutes.

[0093] [Formation of protective layer] On the coated surface of the gas detection film prepared in Example 1, the silicone solution (B-1) was bar-coated so that the film thickness after drying would be 1 μm, heated at 120 °C for 5 minutes, and further heated at 175 °C for 10 minutes to prepare a gas detection film with a protective layer (sample).

[0094] [Example 11] [Formation of protective layer] A gas detection film with a protective layer (sample) was prepared in the same manner as in Example 10, except that on the coated surface of the gas detection film prepared in Example 1, the silicone solution (B-1) was bar-coated so that the film thickness after drying would be 10 μm.

[0095] [Evaluation] For Examples 1, 10, and 11, the measurement methods for the physical properties of each layer and the evaluation method for the gas detection film with a protective layer (sample) will be described.

[0096] (Measurement of Free Volume Radius) The free volume radius of the protective layer was evaluated by the positron annihilation method using a small positron lifetime measurement device (PALS-200A, manufactured by Fuji Inback Co., Ltd.). Considering the distribution of the penetration depth of positrons, the beam intensity was adjusted so that positrons did not reach the layer below the protective layer, and the measurement was carried out.

[0097] The sample, which is a laminate, was attached to a 15 mm × 15 mm silicon wafer, and the positron annihilation lifetime was measured under the following conditions using a sample that had been vacuum degassed at 25°C. Measuring device: Small positron annihilation generator PALS-200A manufactured by Fuji Inback Positron source: 22 Na-based positron annihilation γ-ray detector: BaF 2 Manufactured scintillator and photomultiplier tube Beam intensity: 3 keV Measurement temperature: 25°C Measurement atmosphere: Vacuum Total count number: Approximately 5,000,000 counts

[0098] Then, for the obtained positron annihilation lifetime curve, 3 - 4 component analysis was performed using the non-linear least squares program POSITRONFIT, and from the ones with shorter annihilation lifetimes, τ 1 , τ 2 , τ 3 , τ 4 were used. The average annihilation lifetimes τ 3 , τ 4 capturing the free volume radius on the sub-nm order were used to calculate the free volume radii R 3 , R 4 using the following formula. τ 3 =(1 / 2)[1 - {R 3 / (R 3 +0.166)}+(1 / 2π)sin{2πR 3 / (R 3 +0.166)}]-1 τ 4 =(1 / 2)[1 - {R 4 / (R 4+0.166)}+(1 / 2π)sin{2πR 4 / (R 4 +0.166)}]-1

[0099] Since the positron annihilation lifetime curves measured for the protective layers of Examples 10 and 11 had two peaks, as described above, the free volume radii R 3 , R 4 corresponding to each peak were measured.

[0100] (Sweat resistance evaluation) The surface of the gas detection film (sample) was rubbed with absorbent cotton containing water, and the degree of discoloration was observed and evaluated according to the following criteria. In Examples 10 and 11, the surface of the protective layer was rubbed, and in Example 1 without a protective layer, the surface of the dye layer was rubbed and evaluated. 〇 (good): No discoloration was observed. × (poor): Discoloration was observed at one or more places.

[0101]

Table 3

[0102] (Discussion) In Example 1 without a protective layer, discoloration was observed when the surface was rubbed with absorbent cotton containing water, whereas in Examples 10 and 11, no discoloration was observed. It was found that in Examples 10 and 11, even with a protective layer, since the free volume radius of the protective layer was large, the target gas to be detected and water vapor could permeate, and the chromic dye could respond to the target gas to be detected and be detected. Incidentally, when a protective layer is provided, it has also been confirmed that if the free volume radius of the protective layer is less than 0.35 nm, for example, about 0.26, the responsiveness to the target gas to be detected decreases. Furthermore, comparing Examples 10 and 11, it was found that the smaller the thickness of the protective layer, the higher the responsiveness to the target gas to be detected and the shorter the detection time.

[0103] From the above Examples, Comparative Examples, and the tests conducted by the present inventors to date, it has been found that by providing a protective layer, discoloration, pigment dropout, etc. can be prevented even when water comes into contact with the surface of the gas detection film with the protective layer. Also, if the free volume radius of the protective layer is large, for example, larger than the molecular size of the gas to be detected or water vapor, the protective layer can permeate the gas to be detected and water vapor. Therefore, it is considered that the pigment layer can retain water and collect the gas to be detected. Further, it has been found that if the thickness of the protective layer is too large, it takes time to permeate the protective layer and the response time becomes long. From this, it can be considered that the free volume radius of the protective layer is preferably 0.35 nm or more and 1 nm or less.

Claims

1. A detector having a pigment layer, wherein the pigment layer contains a chromic pigment and a hydrophilic resin, and the thickness of the pigment layer is 0.1 μm or more and 1 μm or less.

2. The detector according to Claim 1, wherein the pigment is a pH-sensitive pigment.

3. The detector according to Claim 1, wherein the hydrophilic resin has a polar group.

4. The detector according to Claim 1, wherein the hydrophilic resin is one or a combination of two or more selected from polyvinyl alcohol, polyvinyl pyrrolidone, polyethyleneimine, polyacrylic acid, sodium polyacrylate, poly(4-styrenesulfonic acid), poly(4-styrenesulfonic acid sodium), polyethylene oxide, water-soluble cellulose ether, and polyallylamine hydrochloride.

5. The detector according to Claim 1, further having a substrate layer.

6. The detector according to Claim 1, further having a protective layer.

7. The detector according to Claim 6, wherein the protective layer has a free volume radius of 0.35 nm or more and 1 nm or less.

8. The detector according to Claim 6, wherein the protective layer contains silicone.

9. The detector according to Claim 6, wherein the thickness ratio (protective layer / pigment layer) of the protective layer to the pigment layer is 1 or more and 100 or less.

10. The detector according to Claim 1, wherein the detected substance is a basic gas.

11. The detector according to Claim 1, wherein the detected substance is a biological gas.

12. A gas detection method, characterized by using the detector according to any one of Claims 1 to 11.

13. A detection device comprising the detector according to any one of Claims 1 to 11.

14. The detection device according to Claim 13, which is worn on a living body and used for detecting biological gas.

15. The detection device according to Claim 14, which has the pigment layer and the protective layer, and the protective layer is disposed on the biological side of the pigment layer.

Images