JP7188692B2 - temperature sensor - Google Patents

Description

TECHNICAL FIELD The present invention relates to a temperature sensor, and more particularly to a temperature sensor that exhibits stable sensor characteristics even in a high-humidity environment, in contact with moisture such as raindrops and perspiration, and in contact with oil components such as human fat.

A biological information measuring device that measures biological information by attaching a flexible substrate having a temperature sensor to a living body is known (for example, JP-A-08-154903, JP-A-2014-217707 (Patent Documents 1 and 2). reference). By using the biological information measuring device, it is possible to monitor biological information, thereby enabling physical condition management, early detection of diseases, management of patient's condition, and the like. These devices are usually equipped with thermocouples or semiconductor sensors as temperature sensors.

Also, a resistive temperature sensor using an aggregate of carbon nanotubes is known (see, for example, Japanese Patent Application Laid-Open No. 2012-122864 (Patent Document 3)).

A sensor portion of the temperature sensor has a structure sandwiched between a flexible substrate and a cover member for the purpose of protecting the sensor from the external atmosphere. Softness is required for the cover member, and silicone rubber is often used as a material with low skin irritation. However, since silicone rubber has high water vapor permeability and swells with human fat, there is a problem that the sensor characteristics fluctuate due to infiltration of water and oil components.
Also, conventional temperature sensors mounted on flexible substrates are expensive to manufacture.

JP-A-08-154903 JP 2014-217707 A JP 2012-122864 A Japanese Patent No. 2990646 Japanese Patent No. 3413713 Japanese Patent No. 3239717 Japanese Patent No. 3077536

SUMMARY OF THE INVENTION It is an object of the present invention to provide a temperature sensor that can be manufactured at low cost, has stable sensor characteristics even when the surrounding environment changes, and can accurately measure temperature. for the purpose.

In order to achieve the above object, the present invention provides the following temperature sensor.
1.
A temperature sensor using a resistance portion whose electrical resistance changes according to temperature, comprising: a substrate on which the resistance portion is arranged; a cover member that sandwiches and seals the resistance portion between the substrate and the substrate; and the resistance portion. and a plurality of electrodes for electrical resistance measurement that are electrically connected to the cover member and led out from the cover member, and the resistance portion includes tin oxide (SnO ₂ ), tungsten oxide (WO ₃ ), and nickel oxide. (NiO) and at least one kind of metal oxide particles selected from indium oxide (In ₂ O ₃ ), carbon nanotubes, and a mixture of metal oxide particles and carbon nanotubes composed only of inevitable impurities, A temperature sensor, wherein the cover member is made of a perfluoropolyether fluororubber obtained by cross-linking a fluororubber composition containing a perfluoro compound having a perfluoropolyether structure in its main chain as a base polymer.
2.
2. The temperature sensor according to 1, wherein the cross-linking site of the perfluoro compound is Si--CH=CH ₂ , and the cross-linking system of the fluorine-containing rubber composition is hydrosilylation addition reaction cross-linking or peroxide cross-linking.
3.
3. According to 1 or 2, wherein the resistor portion is formed by applying or printing a dispersion or paste containing the metal oxide particles and the carbon nanotube onto a substrate on which a plurality of electrodes are formed. temperature sensor.
4.
4. The resistance part according to any one of 1 to 3, which is composed of a mixture of carbon nanotubes and metal oxide particles in which the mass ratio of the carbon nanotubes and metal oxide particles is 1:100 to 1:2000. temperature sensor.
5.
5. The temperature sensor according to any one of 1 to 4, wherein the carbon nanotube is a single-walled carbon nanotube.
6.
In the mixture of the metal oxide particles and the carbon nanotubes, the metal oxide particles are filled to form aggregates, the carbon nanotubes are arranged between the metal oxide particles, and the surfaces of the metal oxide particles and the carbon nanotubes are arranged. 6. The temperature sensor according to any one of 1 to 5, which has a structure in which the carbon nanotube surface is in contact with the surface.
7.
7. The temperature sensor according to any one of 1 to 6, wherein the carbon nanotubes have an average length of 0.5 to 50 μm, and the metal oxide particles have an average particle size of 1 to 500 nm.
8.
Any one of 1 to 7, wherein the substrate is a laminate film in which a metal layer is sandwiched between polyethylene terephthalate films, polyimide films, polyester films, and polyethylene naphthalate films, or any one film selected from these. The temperature sensor according to any one of the above.

According to the present invention, since the resistance section is sealed by the substrate and the cover member made of perfluoropolyether-based fluororubber, it exhibits stable sensor characteristics that are not affected by the environment, enabling accurate temperature measurement. be.

1 is a schematic cross-sectional view showing the configuration of an embodiment of a temperature sensor according to the present invention; FIG. 1 is a graph showing measurement results of an environmental experiment in Example 1 (when a perfluoropolyether fluorine-containing rubber is used for a cover member). 4 is a graph showing measurement results of an environmental experiment in Comparative Example 1 (when silicone rubber is used for the cover member).

An embodiment of a temperature sensor according to the present invention will be described below with reference to the drawings. The configurations shown in the drawings and the following description are examples, and the scope of the present invention is not limited to those shown in the drawings and the following description.

[Temperature sensor]
FIG. 1 is a schematic cross-sectional view showing the configuration of a temperature sensor according to the present invention.
A temperature sensor 10 according to the present invention is a temperature sensor that uses a resistor portion 3 whose electrical resistance changes according to temperature, and the resistor portion 3 is placed between a substrate 2 on which the resistor portion 3 is arranged. A cover member 4 serving as a protective layer that is sandwiched and sealed, and a plurality of electrodes (a first electrode 5 and a second electrode) for electrical resistance measurement electrically connected to the resistance section 3 and led out from the cover member 4. 6), and the cover member 4 is made of a perfluoropolyether-based fluororubber obtained by cross-linking a fluororubber composition containing a perfluoro compound having a perfluoropolyether structure in its main chain as a base polymer. It is characterized by being That is, the present invention provides a temperature sensor function by providing a resistor section 3 containing metal oxide particles and carbon nanotubes on a substrate 2 on which a plurality of electrodes (first and second electrodes 5 and 6) are formed. have. The temperature sensor 10 also includes a cover member (protective layer) 4 covering the periphery (upper surface and side surfaces) of the resistance portion 3 on the substrate 2, and covering the resistance portion 3 with the substrate 2, the cover member 4, and the plurality of electrodes (first and side surfaces). It has a structure in which it is sealed with the second electrodes 5 and 6) to block water vapor and the like from the external environment.

Here, in the temperature sensor using the resistor portion 3 whose electric resistance changes according to temperature, the material of the resistor portion 3 must be (1) that the resistor portion 3 has high temperature sensitivity in the measurement temperature range (it is (2) the electrical resistance value of the resistor portion 3 is within a range measurable by the measuring circuit; (3) the electrical resistance of the resistor portion 3 in the measurement temperature range is required to be stable.

The resistance section 3 included in the temperature sensor 10 is preferably made of a mixture of predetermined metal oxide particles and carbon nanotubes. This resistor portion 3 has characteristics that satisfy the above three conditions. This has been verified by experiments conducted by the inventors. Therefore, the temperature sensor 10 is capable of accurate temperature measurement. The measurement temperature range of the temperature sensor 10 can be a temperature range included in the temperature range of 0° C. or higher and 60° C. or lower, for example.

The metal oxide particles contained in the resistor portion 3 are at least one metal selected from tin oxide (SnO ₂ ), tungsten oxide (WO ₃ ), nickel oxide (NiO), and indium oxide (In ₂ O ₃ ). Particles of oxide are preferred. Of these, tin oxide particles are most preferred from the viewpoint of long-term stability and cost.

The metal oxide particles preferably have an average particle diameter of 1 nm or more and 500 nm or less, more preferably 5 nm or more and 100 nm or less.
The average particle diameter of the metal oxide particles can be obtained, for example, as a cumulative weight average value D50 (or median diameter) by a laser beam diffraction method.

The carbon nanotube contained in the resistance part 3 may be a single walled carbon nanotube (SWCNT) or a multi walled carbon nanotube (MWCNT), Single-walled carbon nanotubes are preferred.

The average length of the carbon nanotubes included in the resistor portion 3 is preferably 0.5 μm or more and 50 μm or less. This allows the temperature sensor 10 to have excellent temperature sensitivity and high stability.
The average length of the carbon nanotubes can be obtained, for example, by measuring the length of 100 or more points from an SEM image (e.g., 5000 times magnification) of a scanning electron microscope (SEM) and calculating the arithmetic mean value thereof. .

Moreover, there is no particular restriction on the average outer diameter of the carbon nanotubes. When obtaining the average outer diameter, for example, it can be obtained using means such as a transmission electron microscope (TEM).

It is preferable that the mass ratio of the carbon nanotubes and the metal oxide particles contained in the resistor portion 3 is, for example, 1:100 to 1:2000. That is, the mixture of metal oxide particles and carbon nanotubes can contain 100 to 2000 times the total weight of the carbon nanotubes in the mixture of metal oxide particles.

The mixture of the metal oxide particles and the carbon nanotubes forming the resistance section 3 is preferably configured such that the surfaces of the metal oxide particles and the carbon nanotubes are in direct contact with each other. In addition, in such a mixture of metal oxide particles and carbon nanotubes, for example, the metal oxide particles are filled to form an aggregate, and the carbon nanotubes are arranged between the metal oxide particles. It is preferable to have a mode in which the surface of the substance particle and the surface of the carbon nanotube are in contact with each other. As a result, the metal oxide particles and the carbon nanotubes can be electrically interacted with each other, and the temperature sensitivity of the resistance portion 3 (magnitude of change in electrical resistance with respect to temperature) can be increased.

Moreover, the mixture of the metal oxide particles and the carbon nanotubes forming the resistor portion 3 is preferably composed only of the metal oxide particles, the carbon nanotubes and the unavoidable impurities. The unavoidable impurities include, for example, carbon substances (amorphous carbon, carbon black, etc.) produced as impurities during the synthesis of carbon nanotubes, fine particles of catalyst used during the synthesis of carbon nanotubes, and the like. This mixture may also contain residual impurities such as a dispersant (surfactant) contained in the dispersion liquid used when forming the resistance portion 3 .

Moreover, the resistor portion 3 is preferably a film in which a mixture of the metal oxide particles and carbon nanotubes is formed on the substrate 2 with a predetermined thickness and a predetermined shape (for example, a rectangular shape). It is preferable that the thickness of the resistance portion 3 is, for example, 0.01 μm or more and 1 mm or less.

In addition, the resistor part 3 is formed by coating or printing a dispersion or paste containing metal oxide particles and carbon nanotubes on the substrate 2 on which a plurality of electrodes (first and second electrodes 5 and 6) are formed. A film formed by a process is more preferable.

As a method for forming the resistor portion 3, methods such as coating, printing, and vacuum deposition can be enumerated. It is suitable from the point of view. For example, first, a dispersion of metal oxide particles and carbon nanotubes is prepared, and this dispersion is applied onto a substrate 2 provided with a plurality of electrodes (first electrode 5 and second electrode 6), and then a coating film is formed. The resistance portion 3 can be formed by drying. At this time, the resistor portion 3 having a desired thickness can be formed by repeating this application and drying a plurality of times. In addition, the dispersion may further contain a dispersant (surfactant). As a result, the metal oxide particles and the carbon nanotubes can be uniformly dispersed in the liquid, and the resistor section 3 can be formed in which the metal oxide particles and the carbon nanotubes are uniformly dispersed. Moreover, the solvent of the dispersion liquid is preferably water, for example. The dispersant can be removed by washing the dried coating film.

The substrate 2 is a base material that supports the resistor portion 3 and a plurality of electrodes (first and second electrodes 5 and 6) and has high gas barrier properties (gas impermeability, air impermeability) that does not allow permeation of water vapor or the like. , For example, a laminate film in which a metal layer is sandwiched between polyethylene terephthalate (PET) films, polyimide films, polyester films, and polyethylene naphthalate (PEN) films, or any one film selected from these Preferably. The metal layer of the laminate film may be a metal foil or a vapor-deposited metal film.
Also, the substrate 2 preferably has a thickness of 1 μm or more and 500 μm or less.

As a result, the substrate 2 can have a high gas barrier property, and it is possible to suppress water or the like from being adsorbed to the resistance portion 3 and affecting the electrical resistance of the resistance portion 3 . Moreover, the thermal conductivity of the substrate 2 can be improved, and the temperature sensitivity of the temperature sensor 10 can be improved.

Also, the substrate 2 is preferably a flexible substrate. As a result, the temperature sensor 10 can be attached so that the outer surface of the substrate 2 is in contact along the curved surface of the object to be temperature-measured, such as the skin of a living body.

The plurality of electrodes in the present invention are electrodes for electrical resistance measurement that are electrically connected to the resistance section 3 so as to measure the electrical resistance of the resistance section 3 and are led outside the cover member 4 .

The plurality of electrodes preferably consists of two electrodes electrically connected to the resistor section 3 for measuring the electrical resistance of the resistor section 3 by a two-terminal measurement method, and the resistance of the resistor section 3 by a four-terminal measurement method. It preferably consists of four electrodes which are electrically connected to the resistance section 3 for measuring the electrical resistance. For example, when the first electrode 5 and the second electrode 6 included in the temperature sensor 10 have the structure shown in FIG. 1, the electric resistance of the resistance section 2 can be measured by the two-terminal measurement method. The configuration based on the two-terminal measurement method will be mainly described below.

The first electrode 5 and the second electrode 6 are, for example, silver electrodes and gold electrodes. The first electrode 5 and the second electrode 6 are preferably formed on the substrate 2 or the resistor portion 3 by a printing method using conductive paste or conductive ink.

The thicknesses of the first electrode 5 and the second electrode 6 are preferably 0.1 μm or more and 20 μm or less in order to reduce wiring resistance. Moreover, the distance between the first electrode 5 and the second electrode 6 is preferably 0.05 mm or more and 2 cm or less. A resistor portion 3 is arranged so as to fill the space between the first electrode 5 and the second electrode 6 .

The first electrode 5 and the second electrode 6 may be provided between the substrate 2 and the resistor section 3 as long as the first electrode 5 and the second electrode 6 are electrically connected to the resistor section 3. , may be provided between the resistance portion 3 and the cover member 4 . Moreover, the resistor part 3 may be provided so as to partially overlap the first electrode 5 and the second electrode 6 and be provided like a bridge connecting the first electrode 5 and the second electrode 6 . The end portions of the first electrode 5 and the second electrode 6 and the resistance portion 3 may be provided between them so as to be in contact with each other.

The temperature sensor 10 includes a cover member 4 that covers the resistor section 3 and serves as a protective layer and a sealing layer. Further, the substrate 2 and the cover member 4 are provided so as to sandwich the resistor portion 2 therebetween and seal them.

As the material of the cover member 4, it is preferable to use a polymer resin material that is excellent in flexibility, gas barrier properties (also referred to as gas barrier properties, gas impermeability, and air impermeability) and oil resistance.
An elastic material is preferable as a material having excellent flexibility. Examples of such materials include various rubber materials, but from the viewpoint of workability and not damaging the sensor, it is preferable that (the composition) be in a liquid state when uncured. Materials that are liquid when uncured include silicone rubber compositions, modified urethane rubber compositions, modified acrylic rubber compositions, modified polyether rubber compositions, and liquid EPDM (ethylene-propylene-diene copolymers). ) (EPDM composition), liquid fluororubber (fluorine-containing rubber composition), etc., but when considering application to wearable applications, from the viewpoint of skin irritation, silicone rubber or liquid fluororubber is preferred. Although it is preferable, liquid fluororubber (fluorine-containing rubber composition) is selectively used in the temperature sensor of the present invention in consideration of its low moisture permeability.

The liquid fluororubber (fluororubber composition) used in the present invention has a perfluoro compound having a perfluoropolyether structure in its main chain as a base polymer. That is, the cover member 4 is made of a perfluoropolyether fluororubber obtained by cross-linking a fluororubber composition (liquid fluororubber) having a perfluoro compound having a perfluoropolyether structure in its main chain as a base polymer. Become.

The perfluoro compound preferably has Si—CH═CH ₂ as a cross-linking site, and the cross-linking system of the fluororubber composition (liquid fluororubber) is hydrosilylation addition reaction cross-linking or peroxide cross-linking. In particular, addition reaction cross-linking is more preferable considering that by-products are not generated during cross-linking.

Among these, perfluoropolyether fluorine-containing rubbers include:
(A) an alkenyl group-containing perfluoro compound having at least two alkenyl groups in the molecule and a divalent perfluoropolyether structure in the main chain;
Curing a crosslinkable fluorine-containing rubber composition containing (B) a reinforcing filler and (C) an addition-reactive crosslinking agent having a hydrosilyl group in the molecule in sufficient amounts to cure the component (A). It is preferable that the

The alkenyl group-containing perfluoro compound of component (A) is preferably a linear perfluoropolyether compound represented by the following general formula (1).

［式中、ＸおよびＸ’はそれぞれ独立に二価の有機基である。ａは独立に０又は１、Ｌは２～６の整数、ｂ及びｃはそれぞれ独立に０～２００の整数である。］

[In the formula, X and X′ are each independently a divalent organic group. a is independently 0 or 1, L is an integer of 2-6, and b and c are each independently an integer of 0-200. ]

These linear perfluoro compounds can be used singly or in combination of two or more.

Reinforcing fillers of component (B) include fumed silica, wet silica, pulverized silica, calcium carbonate, diatomaceous earth, carbon black, various metal oxide powders, etc., and these are treated with various surface treatment agents. can be anything. Among these, fumed silica is particularly preferred from the viewpoint of improving mechanical strength, and fumed silica treated with a silane-based surface treatment agent is more preferred from the viewpoint of improving dispersibility.

The amount of the reinforcing filler of component (B) to be added is preferably 1 to 200 parts by mass per 100 parts by mass of component (A).

Component (C) is a cross-linking agent for curing the alkenyl group-containing perfluoro compound of component (A). It is a reactive cross-linking agent.

Component (C) is an organosilicon compound such as an organohydrogenpolysiloxane having at least two hydrosilyl groups (SiH groups) in one molecule. From the viewpoint of uniformity, one having one or more fluorine-containing monovalent hydrocarbon groups and/or fluorine-containing divalent hydrocarbon groups in one molecule is preferred.

Component (C) may be added in an amount sufficient to cure component (A). The amount is such that the molar ratio of the group (SiH group) is 0.5 to 2.0.

Furthermore, a catalyst for promoting the addition reaction between the alkenyl group in component (A) and the hydrosilyl group (SiH group) in component (C) is usually required, and this hydrosilylation reaction catalyst is generally a noble metal compound , and because of its high cost, relatively easily available platinum or platinum group metal compounds such as platinum compounds are often used.

The amount of platinum or a platinum group metal compound such as a platinum compound to be added may be a so-called catalytic amount, but is 0.1 to 1,000 ppm as platinum group metal atoms relative to component (A).

The cover member 4 is formed so as to cover the entire resistance portion 3 . Moreover, the thickness of the cover member 4 is not particularly limited as long as it exhibits a gas barrier property.

The cover member 4 may be formed by cross-linking the perfluoropolyether fluorine-containing rubber composition. The curing conditions are generally 100° C. to 200° C. for 30 seconds to 15 minutes, and particularly 100° C. to 180° C. for 30 seconds to 15 minutes. Furthermore, in order to make the curing more complete, post-curing may be performed under the conditions of 120° C. to 200° C. for 30 minutes to 4 hours.

The addition reaction crosslinking type perfluoropolyether fluorine-containing rubber composition described above is described in detail in Japanese Patent No. 2990646, Japanese Patent No. 3413713, Japanese Patent No. 3239717 and Japanese Patent No. 3077536. Commercially available products can be used as such fluorine-containing rubber compositions. etc., and particularly preferred are the SIFEL2000 series for adhesion and coating (manufactured by Shin-Etsu Chemical Co., Ltd.) typified by the trade names SIFEL2618/SIFEL2610/SIFEL2614/SIFEL2617/SIFEL2661/SIFEL2662.

When measuring the temperature using the temperature sensor 10 of the present invention, a current source for applying current to the resistance portion 3 and an ammeter for measuring the current value are wired to the first electrode 5 and the second electrode 6. and a voltmeter for measuring the potential difference between the first electrode 5 and the second electrode 6 is wired to the first electrode 5 and the second electrode 6 (two-terminal measurement method ). As a result, a current value when a current is passed between the first electrode 5 and the second electrode 6 and a potential difference (voltage value) appearing between the first electrode 5 and the second electrode 6 are measured. The electrical resistance value of the resistance portion 3 can be calculated from the value. The resistance value is then converted to temperature. This conversion method may be a known method. For example, a correspondence relationship between the electrical resistance value measured by the temperature sensor 10 and the temperature indicated by a reference temperature sensor such as a thermocouple having known characteristics is obtained as a reference table. , the electrical resistance value of the temperature sensor 10 measured as described above may be converted to temperature using a lookup table.
The electrical resistance value of the resistance portion 3 may be measured by applying a pulse current to the resistance portion 3 . As a result, it is possible to prevent the resistance portion 3 from generating heat when a current flows through the resistance portion 3 . Moreover, power consumption of the temperature sensor 10 can be reduced.

According to the temperature sensor 10 of the present invention, the resistance portion 3 is sandwiched and sealed between the substrate 2 having gas barrier properties and the cover member 4, so that water, oil, etc. are not absorbed or penetrated by the resistance portion 3. can be suppressed, and the electrical resistance of the resistance portion 3 can be stabilized. Therefore, the temperature can be measured accurately.
Moreover, since the temperature sensor 10 has such a configuration, the electrical resistance of the resistance portion 3 can be easily measured. Furthermore, the temperature sensor 10 can be made thinner, and the manufacturing cost of the temperature sensor can be reduced.

EXAMPLES The present invention will be described in more detail with reference to Examples and Comparative Examples below, but the present invention is not limited to these Examples.

[Example 1]
(Fabrication of temperature sensor)
A temperature sensor shown in FIG. 1 was produced by the following procedure.
First, a dispersion liquid was prepared by mixing raw materials (carbon nanotubes, metal oxide particles), a dispersant, and water for the following resistor material.
Carbon nanotube (CNT): single-walled carbon nanotube (manufactured by OCSiAl, trade name TUBALL single-walled carbon nanotube) (average outer diameter 1.8 nm, average length 5 μm),
Metal oxide particles: SnO2 nanoparticles (manufactured by Sigma _- Aldrich) (average particle size 100 μm),
dispersant: sodium dodecyl sulfate (SDS),
Water: distilled water.
The concentration of carbon nanotubes in the dispersion is 0.2% by mass, and the concentration of metal oxide particles is 75% by mass.

Next, a PET film (substrate 2) having a thickness of 38 μm was prepared on which two silver electrodes (first electrode 5 and second electrode 6) were provided by screen printing. At this time, the distance between the first electrode 5 and the second electrode 6 was 0.6 mm to 5 mm.
While the PET film on which the silver electrode is formed is heated on a hot plate at 110° C., the dispersion prepared above overlaps with a part of each of the two silver electrodes on the PET film and fills the space between the two silver electrodes. A liquid was applied and the applied film was dried. The application and drying were repeated several times to fabricate the resistor portion 3 .
Next, the PET film provided with the resistance portion was immersed in water to wash the resistance portion and remove the dispersing agent. After that, it was dried by placing it in an oven at 90° C. for 1 hour, and the resistance portion 3 was produced.
Finally, an addition reaction cross-linking perfluoropolyether system containing the above components (A) and (C) and containing fumed silica surface-treated with a silane-based surface treatment agent as a reinforcing filler for component (B) A fluorine-containing rubber composition (product number: SIFEL2661, manufactured by Shin-Etsu Chemical Co., Ltd.) is coated so as to cover the entire resistance part 3 and part of each of the two silver electrodes, and placed in an oven at 90 ° C. for 12 hours or more. A temperature sensor was produced by curing by putting it in.

[Comparative Example 1]
In Example 1, a heat-curable silicone rubber composition (product number: KJR-9060U, manufactured by Shin-Etsu Chemical Co., Ltd.) was used in place of the perfluoropolyether-based fluorine-containing rubber composition, except for Example 1. A temperature sensor was produced in the same manner as above.

(environmental experiment)
Using the temperature sensor produced as described above, set it in an environment test machine that can control the temperature, and with the humidity inside the test machine kept at about 40% RH, the environmental temperature inside the test machine is set at 25 ° C to 45 ° C. The electrical resistance value of the resistance part when changed was measured by the two-terminal measurement method. A thermocouple (T type) was placed near the resistance portion of the temperature sensor, and the temperature detected by the thermocouple was measured as the actual temperature at the same time as the electrical resistance of the resistance portion was measured.
In addition, before installing the temperature sensor in the environmental tester, obtain the correspondence relationship between the electrical resistance value measured by the temperature sensor and the temperature detected by the thermocouple as a reference table, and measure as described above. The measured electric resistance value of the temperature sensor was converted into a temperature using a reference table, and the temperature detected by the sensor was obtained.

The measurement results of Example 1 are shown in FIG. 2, and the measurement results of Comparative Example 1 are shown in FIG.
As shown in FIG. 2, the temperature detected by the temperature sensor of Example 1 (sensor detection temperature) did not differ from the actual temperature even after the test time exceeded 20 hours. Stable sensor characteristics were obtained without being affected. In addition, no difference from the actual temperature was observed with respect to changes in the rise and fall of the environmental temperature, indicating good temperature sensitivity.
On the other hand, the temperature detected by the temperature sensor of Comparative Example 1 (sensor detection temperature), as shown in FIG. When repeated, the temperature tended to become lower than the actual temperature and the difference from the actual temperature increased with the lapse of test time. After that, when the test was continued while the environmental temperature was kept constant at 25°C, the sensor detected temperature remained different from the actual temperature. It is presumed that this is because the relationship between the temperature of the resistance portion of the temperature sensor and the electrical resistance value changed due to the influence of water vapor that penetrated through the cover member.

2 substrate 3 resistance part 4 cover member 5 first electrode 6 second electrode 10 temperature sensor

Claims (8)

A temperature sensor using a resistance portion whose electrical resistance changes according to temperature, comprising: a substrate on which the resistance portion is arranged; a cover member that sandwiches and seals the resistance portion between the substrate and the substrate; and the resistance portion. and a plurality of electrodes for electrical resistance measurement that are electrically connected to the cover member and led out from the cover member, and the resistance portion includes tin oxide (SnO ₂ ), tungsten oxide (WO ₃ ), and nickel oxide. (NiO) and at least one kind of metal oxide particles selected from indium oxide (In ₂ O ₃ ), carbon nanotubes, and a mixture of metal oxide particles and carbon nanotubes composed only of inevitable impurities, A temperature sensor, wherein the cover member is made of a perfluoropolyether fluororubber obtained by cross-linking a fluororubber composition containing a perfluoro compound having a perfluoropolyether structure in its main chain as a base polymer. 2. The temperature according to claim 1, wherein the cross-linking site of the perfluoro compound is Si—CH═CH ₂ , and the cross-linking system of the fluorine-containing rubber composition is hydrosilylation addition reaction cross-linking or peroxide cross-linking. sensor. 3. The resistor part is formed by applying or printing a dispersion or paste containing the metal oxide particles and carbon nanotubes onto a substrate on which a plurality of electrodes are formed. The temperature sensor described in . 4. Any one of claims 1 to 3, wherein the resistor portion is composed of a mixture of carbon nanotubes and metal oxide particles having a mass ratio of the carbon nanotubes to the metal oxide particles of 1:100 to 1:2000. A temperature sensor as described above . The temperature sensor according to any one of claims 1 to 4, wherein the carbon nanotubes are single-walled carbon nanotubes. In the mixture of the metal oxide particles and the carbon nanotubes, the metal oxide particles are filled to form aggregates, the carbon nanotubes are arranged between the metal oxide particles, and the surfaces of the metal oxide particles and the carbon nanotubes are arranged. 6. The temperature sensor according to any one of claims 1 to 5, having a structure in contact with the surface of the carbon nanotube. The temperature sensor according to any one of claims 1 to 6, wherein the carbon nanotubes have an average length of 0.5 to 50 µm, and the metal oxide particles have an average particle diameter of 1 to 500 nm. Claims 1 to 7, wherein the substrate is a laminate film in which a metal layer is sandwiched between any one of polyethylene terephthalate film, polyimide film, polyester film and polyethylene naphthalate film, or any one film selected from these films. The temperature sensor according to any one of .

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