JP2007212365A - Oxygen quenching paint and oxygen concentration measurement system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an oxygen quenching paint improved in peeling from the coated body or tearing of the paint film itself by expansion/shrinkage of the paint film caused by the temperature change. <P>SOLUTION: The oxygen quenching paint contains pigments and oxygen permeable polymers as a binder which are made to emit light by excitation light, in which the weight mean molecular weight of the oxygen permeable polymers is in a range of 80000-300000. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an oxygen quenching paint and an oxygen concentration measuring apparatus using the oxygen quenching paint.

  As the dye contained in the oxygen-quenching paint, metal porphyrins such as platinum porphyrins, transition metal complexes such as ruthenium complexes, and the like are used. When these dyes are irradiated with excitation light, the dye molecules transition to an excited state, and the excited dye molecules (excitation molecules) emit light (luminescence) having a wavelength longer than that of the excitation light when returning to the ground state. However, when oxygen molecules exist around the excited molecules, the excited molecules lose their energy to the oxygen molecules, and a quenching phenomenon occurs in proportion to the collision probability between the oxygen molecules and the excited molecules. That is, the emission intensity of the dye varies depending on the oxygen concentration in the atmosphere around the dye. Therefore, if this emission intensity is measured by an optical sensor such as a CCD camera, the oxygen concentration around the dye can be measured. An oxygen concentration measuring apparatus using such an oxygen concentration measuring method is expected to be applied not only to the automobile field and aerospace related fields but also to various fields.

  In Patent Document 1, an oxygen quenching paint is fixed to the tip of an optical fiber, and the optical fiber is inserted into the fuel cell so that oxygen supplied as a raw material to the cathode electrode of the fuel cell passes through the electrolyte membrane. A method of detecting the oxygen concentration when leaking to the anode electrode has been proposed.

JP 2004-265667 A

  However, since Patent Document 1 does not consider the use environment of a fuel cell used in an environment of a few tens of degrees from the freezing point, the coating film of the oxygen quenching paint fixed to the tip of the optical fiber by a change in the cooling temperature. Expands and contracts, peels off from the optical fiber as the adherend, and tears the coating film itself, and cannot detect the oxygen concentration in the fuel cell over a long period of time. Furthermore, only the oxygen concentration at the gas leak inspection level in the fuel cell can be measured, and the oxygen concentration during power generation cannot be measured.

  The present invention provides an oxygen-quenching coating material that improves peeling from the adherend due to expansion and contraction of the coating film of the oxygen-quenching coating material applied to the adherend and tearing of the coating film itself when the heat changes. .

  The present invention also provides an oxygen concentration measuring apparatus that improves peeling from the adherend and tearing of the light emitting portion itself due to expansion and contraction in a light emitting portion in which an oxygen quenching paint is applied to the adherend during a change in cooling.

  The oxygen-quenching paint of the present invention is an oxygen-quenching paint containing a dye that emits light by excitation light and an oxygen-permeable polymer as a binder. The weight-average molecular weight of the oxygen-permeable polymer is in the range of 80,000 to 300,000. is there.

  The oxygen-quenching coating material preferably further contains a water repellent.

  The oxygen concentration measuring apparatus according to the present invention includes a light-emitting unit in which an oxygen quenching paint including a dye that emits light by excitation light and an oxygen-permeable polymer as a binder is applied to an adherend, and the light-emitting unit. A light irradiation unit that emits excitation light, a light emission measurement unit that measures the light emission intensity of the light emission unit, and a processing unit that calculates an oxygen concentration from the light emission intensity of the light emission unit measured by the light emission measurement unit. The weight average molecular weight of the oxygen permeable polymer is in the range of 80,000 to 300,000.

  Moreover, it is the said oxygen concentration measuring apparatus, Comprising: It is preferable that the said oxygen quenching coating material further contains a water repellent.

  In the oxygen concentration measuring apparatus, it is preferable that the light emitting unit is annealed.

  In the oxygen-quenching paint according to the present invention, the weight-average molecular weight of the oxygen-permeable polymer as a binder is in the range of 80,000 to 300,000, thereby attaching the coating film of the oxygen-quenching paint applied to the adherend. The peeling from the body and the tearing of the coating film itself can be improved.

  In the oxygen concentration measuring apparatus according to the present invention, the weight-average molecular weight of the oxygen-permeable polymer as a binder is in the range of 80,000 to 300,000, so that the light-emitting part coated with an oxygen quenching paint on the adherend and the object to be coated Separation from the wearing body and tearing of the light emitting part itself can be improved. In particular, it is possible to improve the peeling of the light emitting part and the adherend and the tearing of the light emitting part itself at the time of a change in cold temperature, so that long-term use of the oxygen concentration measuring device can be ensured.

  Embodiments of the present invention will be described below.

  First, an example of an oxygen-quenching paint according to an embodiment of the present invention will be described below.

  The oxygen-quenching paint is constituted by dissolving or dispersing a dye, an oxygen-permeable polymer, and a water repellent in a solvent such as water or an organic solvent. The method for adjusting the oxygen-quenching paint is not particularly limited. For example, first, the oxygen-permeable polymer is dissolved in an organic solvent, then the dye is dissolved in the mixed solution, and the mixed solution is further dissolved. It is preferable to dissolve the water repellent. Moreover, as stirring time of each solution for making it melt | dissolve, it becomes like this. Preferably it is 1-60 minutes, More preferably, it is 10-30 minutes. The stirring temperature is preferably around room temperature (25 to 30 degrees).

  The mixing weight ratio of the dye, the oxygen permeable polymer, and the water repellent in the oxygen quenching paint is not particularly limited, but the dye is 0.9 to 4.9 based on the total weight of the oxygen quenching paint. It is preferable that the weight%, the oxygen-permeable polymer is 95 to 99% by weight, and the water repellent is 0 to 0.1% by weight.

  The oxygen-permeable polymer is not particularly limited as long as the weight average molecular weight (Mw) is in the range of 80000-300000, but is preferably in the range of 90000-200000, more preferably in the range of 90000-110,000. is there. Examples of the oxygen permeable polymer include polyolefin resins such as polyethylene and polypropylene, fluorine resins such as polyvinyl fluoride and polyvinylidene fluoride, polycarbonate, polystyrene, polyvinyl chloride, polyvinylidene chloride, polyester, and polytetrafluoroethylene. , And at least one of them can be used. The weight average molecular weight of the oxygen permeable polymer may be adjusted by changing the polymerization conditions such as the catalyst / monomer charge ratio, reaction temperature, type of solvent used, or purification conditions during reprecipitation. A commercially available product having a specified molecular weight may also be used. Specific examples include polystyrene (polystyrene manufactured by AVOCADO, weight average molecular weight 100000). If the weight average molecular weight of the oxygen-permeable polymer is less than 80000, the coating strength of the oxygen-quenching paint applied to the adherend will decrease. If the weight average molecular weight is more than 300,000, the strength of the coating film itself becomes too high, and the coating film itself tends to tear due to expansion and contraction of the coating film when the temperature changes. In general, the average molecular weight includes a weight average molecular weight (Mw) and a number average molecular weight (Mn). It is considered that physical properties important for coating such as viscosity depend on the weight average molecular weight. The oxygen-permeable polymer used in the examples is commercially available, and the method for measuring the weight average molecular weight depends on the manufacturer, but generally gas chromatography (GPO) is used. The glass transition temperature (Tg) of the oxygen permeable polymer is preferably in the range of 85 to 200 degrees, more preferably 100 to 150 degrees.

  The dye is not particularly limited as long as it emits fluorescence, phosphorescence or the like by excitation light and exhibits oxygen quenching property. For example, platinum porphyrin complexes such as platinum octaethylporphyrin and platinum tetrapentafluorophenylporphyrin, transition metal complexes such as phenanthrolin, ruthenium and chloride, polycyclic aromatic compounds such as pyrene and perylene, and derivatives thereof Can be used. In particular, platinum tetrapentafluorophenylporphyrin or phenanthroline / ruthenium / chloride is preferable from the viewpoint of emission lifetime, emission intensity, and thermal stability. Specifically, Pt (II) meso-tetra penta produced by Frontier Scientific Porphine Products. Fluorophenyl porphine (hereinafter referred to as Pt (TFPP)) or tris (Bathophaneanthroline) Ruthenium Dichloride manufactured by GFS Chemical Company.

  The water repellent is not particularly limited as long as it imparts water repellency to the oxygen-quenching paint, but the contact angle with respect to the coating surface is 90% or more, preferably 100% or more. Some are preferred. Specific examples include water-repellent resins such as silicon resins, acrylic resins, and fluorine resins, and mixtures thereof. From the viewpoint of the water-repellent performance of the oxygen-quenching paint, MODIPER (registered trademark) FS720 (manufactured by NOF Corporation), which is a mixture of an acrylic resin and a fluorine resin, can be used.

  The solvent is not particularly limited as long as it is a highly volatile organic solvent. Examples thereof include alcohols such as ethanol, ketones such as methyl ethyl ketone, esters such as ethyl acetate, amide solvents such as N-methylpyrrolidone, and toluene solvents. Toluene can be used in terms of volatility and solubility with pigments.

  After the oxygen quenching paint according to the present embodiment described above is applied, the oxygen quenching paint is applied to the adherend. It is possible to prevent tearing of the coating film itself. Further, by adding a water repellent to the oxygen-quenching paint, it is possible to prevent stagnation of water droplets on the coating film surface even if water droplets adhere to the coating film surface.

  The oxygen-quenching paint according to the present embodiment can be used for a light emitting unit, oxygen partial pressure, and water detection of an oxygen concentration measuring device.

  Next, an oxygen concentration measuring apparatus according to an embodiment of the present invention will be described below.

  FIG. 1 is a schematic diagram showing an example of the configuration of an oxygen concentration measuring apparatus 1 according to an embodiment of the present invention. The oxygen concentration measurement apparatus 1 includes a light irradiation unit 10, a light emission unit 14, a light emission measurement unit 16, and a processing unit 18. The light emitting unit 14 is applied to the adherend 12. The light emission measuring unit 16 is connected to the processing unit 18. The light irradiation unit 10 preferably includes a control unit 20 that controls the light emission timing of the light irradiation unit 10. Furthermore, it is preferable that the light emission measurement unit 16 includes the light emission filter 22 so that only the light emission of the light emission unit 14 can be measured.

  Light (excitation light) irradiated from the light irradiation unit 10 is projected onto the light emitting unit 14 applied to the adherend 12. The light emitting unit 14 is excited and emits light by the projected light. The light emitted from the light-emitting unit 14 has a light emission intensity that changes according to the surrounding oxygen concentration, is detected by the light-emission measuring unit 16, is converted into an electrical signal, and is output. The output electrical signal is sent to the processing unit 18 as the light emission intensity of the light emitting unit 14. The processing unit 18 detects oxygen concentration distribution data corresponding to the emission intensity, and displays or prints out the detection result.

  The light irradiation part 10 will not be restrict | limited especially if the light of the excitation wavelength of the oxygen quenching coating material used for the light emission part 14 is radiated | emitted. The light irradiation unit 10 is, for example, a xenon lamp provided with an optical filter, a metal halide lamp, or an LED. Specifically, Hamamatsu Photonics LED (wavelength 294-395 nm), Nichia Corporation LED NSPB300A (wavelength 465 nm) can be used, and is selected according to the excitation wavelength of the oxygen quenching paint. .

  The light emitting unit 14 is obtained by applying the oxygen quenching paint described above to the adherend 12. The pigment in the oxygen-quenching paint is excited by the light projected from the light irradiation unit 10 and emits light. For example, Pt (TFPP) absorbs violet light having a wavelength of 400 nm and emits phosphorescence having a wavelength of around 650 nm, but the emission intensity is quenched depending on the oxygen concentration around the light emitting portion 14.

  As the oxygen-quenching paint, the same one as described above can be used. For example, as the oxygen permeable polymer, polystyrene (polystyrene manufactured by AVOCADO, molecular weight 100000) is particularly preferable from the viewpoint that an oxygen quenching paint corresponding to a simple air spray gun can be prepared as a coating method. The water repellent is preferably Modiper (registered trademark) FS720 (manufactured by Nippon Oil & Fats Co., Ltd.), which is excellent in water repellency. TFPP) or tris (Bathophaneanthroline) Ruthenium Dichloride manufactured by GFS Chemical Co. is preferable. The method for adjusting the oxygen quenching paint can also be adjusted by the same method as described above, and the mixing weight ratio of the dye, the oxygen permeable polymer and the water repellent in the oxygen quenching paint should be the same. it can.

  As shown in FIG. 1, the light emitting unit 14 is manufactured by applying an oxygen quenching paint to a location on the adherend 12 where the oxygen concentration is detected. The application method is not particularly limited, and examples thereof include an air spray gun, a dispenser, an applicator, screen printing, roll coating, and flow coating. From the viewpoint of workability, an air spray gun is particularly preferable. The thickness of the light emitting portion 14 is 1 μm to 100 μm, preferably 10 μm to 60 μm. If the film thickness is less than 1 μm, it may be difficult to detect the light emission of the light emitting unit 14 by the light emission measuring unit 16. If the film thickness is greater than 80 μm, the light emitting unit 14 itself is torn when the light emitting unit 14 is formed. It may be likely to occur.

  Furthermore, it is preferable to anneal the light emitting portion 14 after application to the adherend 12. By performing the annealing process, the surface of the light-emitting portion 14 becomes smooth, and unevenness in light emission of the light-emitting portion 14 can be reduced, so that the oxygen concentration detection sensitivity can be improved. Furthermore, since the uniformity of the surface state of the light emitting portion 14 is increased and the unevenness of the coating strength of the light emitting portion 14 is strong and weak, it is possible to prevent tearing of the light emitting portion 14 during a change in cooling. The conditions for the annealing treatment are not particularly limited as long as the annealing treatment is maintained at a temperature higher than the glass transition temperature (Tg) of the oxygen-permeable polymer for a certain period of time. For example, when polystyrene (Tg = 82 ° C.) is used as the oxygen permeable polymer, the temperature is 85 ° C. to 200 ° C., preferably 100 ° C. to 150 ° C., and the holding time is 1 minute to 120 minutes, preferably 10 minutes to 60 minutes.

  The light emission measuring unit 16 is not particularly limited as long as it can measure the light emission of the light emitting unit 14. The light emission measuring unit 16 is a photoelectric conversion element such as a photodiode or a CCD. Specifically, as a CCD camera equipped with a CCD, ORCA2ER manufactured by Hamamatsu Photonics, Sensicam 1600 manufactured by PCO, or the like can be given. Examples of the light emission filter 22 include 645FG07-05 (center wavelength: 645 nm) manufactured by ISSI, SC60 (center wavelength: 600 nm) manufactured by Kenko, and the like, and are selected according to the light emission wavelength of the light emitting unit 14.

  With the oxygen concentration measuring apparatus according to the present embodiment described above, the light emitting unit 14 can prevent peeling from the adherend 12 and tearing of the coating film itself even if the light emitting unit 14 expands and contracts due to a change in cold. it can. Therefore, the oxygen concentration can be measured over a long period. Further, by adding a water repellent to the oxygen-quenching paint, even if water droplets adhere to the surface of the coating film, stagnation of the water droplets on the coating film surface can be prevented.

  Therefore, the oxygen concentration measuring apparatus according to the present embodiment measures the concentration of oxygen supplied as a raw material and evaluates the performance of the fuel cell, for example, in a fuel cell used in an environment of a few hundred degrees from a freezing point. It can also be used for an oxygen sensor of an existing engine used in the same environment as described above. Furthermore, it can be used for oxygen concentration measurement in the vicinity of factory equipment where cooling water scatters. It can also be used to measure the oxygen concentration in the cylinder and exhaust manifold of a visualization engine that requires heat resistance. Furthermore, it is possible to apply the above-described oxygen quenching paint described above to the tip of the optical fiber as described in Patent Document 1, and it can be used for performance evaluation of fuel cells and oxygen sensors for fuel cells for electric vehicles. it can.

  Next, as another embodiment of the oxygen concentration measuring apparatus according to the present embodiment, an example in which the oxygen concentration supplied as a raw material to the fuel cell is measured using the oxygen concentration measuring apparatus according to the present embodiment will be described. To do.

  FIG. 2 is a schematic diagram showing an example of the configuration of an oxygen concentration measuring apparatus according to another embodiment of the present invention. Since the light irradiation unit 10, the light emission measurement unit 16, and the processing unit 18 constituting the oxygen concentration measuring device 1 have the same configuration as described above, the description thereof is omitted, but the oxygen quenching paint used in the light emission unit 14 is omitted. The adjustment method and the application method to the fuel cell 3 will be described more specifically below. In addition, in order to detect the oxygen gas concentration in the fuel cell 3, the light emitting section 14 is formed on the inner surface of the oxygen gas flow path 30 (shown in FIG. 3).

  First, the fuel cell 3 shown in FIG. 2 includes an MEA (membrane electrode assembly) 24, an oxygen gas separator 26, and a hydrogen gas separator 28. The oxygen gas separator 26 is formed with an oxygen gas flow path 30 through which oxygen gas passes. Oxygen gas enters from the oxygen gas inlet 32, passes through the oxygen gas flow path 30, and is discharged from the oxygen gas outlet 34. The same applies to the hydrogen gas separator 28 (not shown). In order to detect the concentration of oxygen gas passing through the oxygen gas flow channel 30, the light emitting section 14 is formed on the inner surface of the oxygen gas flow channel 30 (shown in FIG. 3). Further, in order to irradiate the light emitting unit 14 with excitation light and observe the light emission intensity of the light emitting unit 14, the oxygen gas separator 26 uses a transparent plate such as acrylic resin or synthetic quartz.

  FIG. 3 shows, as an example of the configuration of the light emitting unit 14 formed in the oxygen gas flow path 30, a part of the oxygen gas flow path 30 as viewed from the direction of the arrow b in a cross section cut along the arrow a in FIG. It is a representation. The light-emitting portion 14 includes an oxygen-quenching paint (hereinafter referred to as oxygen-quenching paint A) to which a water-repellent agent is not added and an oxygen-quenching paint (hereinafter referred to as oxygen-quenching property) to which a water-repellent agent is added. And a portion to which the coating material B) is applied (application portion B). However, the present invention is not necessarily limited thereto, and may be a portion where only the oxygen quenching paint A is applied, or a portion where only the oxygen quenching paint B is applied.

  Although the adjustment method of the oxygen-quenching paints A and B will be specifically described, it is not limited to this. Oxygen-quenching paint A is an organic solvent such as toluene, and an oxygen-permeable polymer such as polystyrene of 95 to 99% by weight with respect to the total weight of oxygen-quenching paint A is added at 25 to 30 degrees for 10 minutes. Stir for about 30 minutes to dissolve, then add 0.9 to 4.9% by weight of a dye such as Pt (TFPP) to the total weight of the oxygen-quenching coating material A and add 25 to 30 degrees. Then, the mixture is stirred for about 10 to 30 minutes and dissolved. Oxygen-quenching paint B is an organic solvent such as toluene, and an oxygen-permeable polymer such as polystyrene of 95 to 99% by weight based on the total weight of oxygen-quenching paint B is added at 25 to 30 degrees for 10 minutes. Stir for about 30 minutes to dissolve, and then add 0.9 to 4.9% by weight of a dye such as Pt (TFPP) to the total weight of the oxygen-quenching paint B to the mixed solution. Then, a water repellent agent such as a mixture of an acrylic resin and a fluororesin is added as a water repellent agent to the mixed solution for 10 minutes to 30 minutes. It shall be dissolved by stirring for about a minute.

  The method for applying the oxygen-quenching paints A and B will be specifically described, but is not limited thereto. As shown in FIG. 3, the oxygen-quenching coating material B is preferably applied such that a gap is provided with respect to the width d of the oxygen gas flow path 30, and further, ½ or less of the width d of the oxygen gas flow path 30. More preferably, it is applied so as to have a diameter of. This is to ensure the passage of water generated by the power generation reaction of the fuel cell. Since part of the water generated by the power generation reaction of the fuel battery cell 3 is drained into the oxygen gas flow path 30, the oxygen quenching paint B having a water repellent function has the same diameter as the width d of the oxygen gas flow path 30. This is because the oxygen quenching paint B inhibits the drainage of water in the oxygen gas flow path. Moreover, the application part B does not need to be circular, and may be a triangle, a quadrangle, or the like. As a coating method, for example, when applying to the inner side surface of the oxygen gas flow path 30 using an air spray gun filled with the oxygen quenching paint A, a portion where the oxygen quenching paint B is applied with a masking tape or the like is secured in advance. Using an air spray gun filled with oxygen-quenching paint A, the inner surface of oxygen gas flow path 30 was applied, and then the masking tape was peeled off, and an air spray gun filled with oxygen-quenching paint B was used at that location. What is applied is preferred. Furthermore, it is preferable to stabilize the coating film of the oxygen-quenching paint after the application by annealing. The annealing conditions are not particularly limited, but 110 ° C. and 60 minutes are preferable.

  Even if the oxygen concentration measuring device according to another embodiment of the present invention described above is used in a fuel cell used in an environment of a few tens of degrees from the freezing point, the light-emitting unit 14 has the oxygen gas channel 30 inner surface. Therefore, the oxygen concentration measuring device can be used for a long period of time. In addition, by providing the application part B having a water repellent agent, water generated by the power generation reaction of the fuel cell does not adhere to the application part B, so that the oxygen gas concentration in the oxygen gas channel 30 is accurately measured. can do. Furthermore, since the surface of the light emitting portion 14 can be smoothed by the annealing treatment, more accurate light emission intensity can be measured. The oxygen concentration measuring apparatus according to the above embodiments is not limited to those used for fuel cell applications.

  Hereinafter, the present invention will be described more specifically with reference to examples and comparative examples, but the present invention is not limited to the following examples.

(Adjustment of oxygen quenching paints of Examples 1 to 8 and application to adherends)
In 100 ml of toluene, 5000 mg of polystyrene (AVOCADO, weight average molecular weight 100000) as an oxygen permeable polymer was added and stirred for 10 minutes at 25 ° C. to dissolve, and then 75 mg (Frontier Scientific) of Pt (TFPP) as a dye in the mixed solution. Porphrin Products, Inc.) was added and stirred for 10 minutes at 25 degrees to dissolve, and 1.5 g of Modiper (registered trademark) FS720, which is a mixture of acrylic resin and fluororesin, was added to the mixed solution as a water repellent. The mixture was stirred for 10 minutes and dissolved to prepare an oxygen quenching paint. The oxygen quenching paint was applied to a glass plate as an adherend to a thickness of 20 μm with an air spray gun as Example 1, and applied to the glass plate as an adherend to a thickness of 80 μm. This was designated as Example 3. Moreover, what annealed Example 1 and Example 3 for 1 hour by 110 degreeC by oxygen atmosphere in the high temperature tank was set as Example 2 and Example 4, respectively. Examples 5 and 7 were prepared in the same manner as in Examples 1 and 3 with the molecular weight of the polystyrene set to a weight average molecular weight of 280000 (manufactured by AVOCADO). In Examples 6 and 8, Example 5 and Example 7 were annealed at 110 degrees for 1 hour.

(Adjustment of oxygen quenching paints of Comparative Examples 1 to 4 and application to adherends)
In 100 ml of toluene, 5,000 mg of polystyrene as an oxygen permeable polymer (AVOCADO, weight average molecular weight 50000) is added and stirred for 10 minutes at 25 ° C. to dissolve, and then 75 mg of Pt (TFPP) (Frontier Scientific) as a dye in the mixed solution. Porphrin Products, Inc.) was added and stirred for 10 minutes at 25 degrees to dissolve, and 1.5 g of Modiper (registered trademark) FS720 as a water repellent was added to the mixed solution and dissolved by stirring for 10 minutes at 25 degrees. Adjusted. The above-mentioned oxygen-quenching paint was applied to a glass plate as an adherend with an air spray gun to a thickness of 20 μm as Comparative Example 1, and applied to a glass plate as an adherend to a thickness of 80 μm. Was designated as Comparative Example 3. Further, Comparative Example 1 and Comparative Example 3 were annealed in an oxygen atmosphere at 110 ° C. for 1 hour in a high-temperature bath, and were designated as Comparative Example 2 and Comparative Example 4, respectively. The production conditions of Comparative Examples 1 to 4 are shown in Table 1 below.

(Examples 1 to 8 and Comparative Examples 1 to 4 of high temperature steam exposure test)
Examples 1 to 8 and Comparative Examples 1 to 4 were installed 50 mm above the water surface in a beaker in a boiling water state at a temperature of 100 degrees, and Examples 1 to 8 and Comparative Example were in steam generated by boiling water in the beaker. 1-4 were left for 2 hours. The result of the coating-film surface state of Examples 1-8 after that and Comparative Examples 1-4 is shown in following Table 2. Evaluation of the coating film surface state was performed by measuring the coating film surface with a scanning confocal laser microscope (manufactured by Olympus, OLS1200, shape resolution 0.01 μm). The degree of the surface condition was judged from the smoothness of the image displayed on the display.
○: There is no unevenness on the surface of the coating film.
Δ: There are bumpy parts on the surface of the coating film.
X: Destruction (tearing) of the coating film surface or peeling of the entire coating film.

  In Comparative Examples 1 to 4 (the weight average molecular weight of the oxygen-permeable polymer was 50000), the coating film surface itself was destroyed after the high-temperature steam exposure test, and peeled off from the adherend. The coating thickness was tested at 20 μm and 80 μm, but no difference was found in the coating surface state due to the difference in thickness. Furthermore, the effect by annealing treatment was not seen. On the other hand, in Examples 1 and 3 (the weight average molecular weight of the oxygen-permeable polymer is 100,000) and Examples 5 and 7 (the weight average molecular weight of the oxygen-permeable polymer is 280000), the coating itself is torn even after the high-temperature exposure test. No peeling from the adherend occurred, and no difference was observed in the surface state of the coating film due to the difference in coating thickness. However, a part of the coating film surface was uneven. However, even if it is used for the light emitting part of the oxygen concentration measuring device, for example, it does not cause any trouble. The best results were shown in Examples 2 and 4 (the weight-average molecular weight of the oxygen-permeable polymer was 100,000) and Examples 6 and 8 (the weight-average molecular weight of the oxygen-permeable polymer was 280000) after annealing. )Met. Even after the high temperature exposure test, the coating film itself was not torn or peeled off from the adherend, and there were no bumps on the surface of the coating film. The thicknesses of the coating films of 20 μm and 80 μm are coating film thicknesses that can be used as the light emitting part of the oxygen concentration measuring device.

(Method for creating an oxygen concentration test device for fuel cells)
As shown in FIG. 4, the oxygen concentration measuring apparatus 1 uses NSPB 300A (wavelength 465 nm) of LED manufactured by Nichia Corporation as the light irradiation unit 10, Sensicam 1600 manufactured by PCO as the light emission measuring unit 16, and a light emission filter For No. 22, 645FG07-05 (center wavelength: 645 nm) manufactured by ISSI was used, and a personal computer was used as the processing unit 18. As shown in FIG. 3, the light-emitting unit 14 has an oxygen-quenching paint A and an oxygen-quenching paint B on the surface of the oxygen gas flow path 30 in the oxygen gas separator 26 using an acrylic resin transparent plate by an air spray gun. Formed. The coating thickness was 20 μm. Oxygen-quenching paint A was added with 5000 mg of polystyrene (produced by AVOCADO, weight average molecular weight 100000) as an oxygen-permeable polymer in 100 ml of toluene and dissolved by stirring at 25 degrees for 10 minutes. Pt (TFPP) 75 mg (manufactured by Frontier Scientific Porbrin Products) was added and stirred for 10 minutes at 25 ° C. to dissolve and adjust. The oxygen-quenching paint B was prepared by adding 1.5 g of MODIPER (registered trademark) FS720, which is a mixture of an acrylic resin and a fluororesin, as a water repellent to the oxygen-quenching paint A and stirring it at 25 ° C. for 10 minutes for dissolution. . When applying to the inner surface of the oxygen gas flow channel 30 using an air spray gun filled with the oxygen quenching paint A, the coating method is a masking that is ½ the width d of the oxygen gas flow channel 30. After securing the location where the oxygen-quenching paint B is applied with a tape and applying it to the inner surface of the oxygen gas flow path 30 using an air spray gun filled with the oxygen-quenching paint A, the masking tape is peeled off and oxygen is applied to the location. It applied using the air spray gun with which the quenching paint B was filled. Further, after the coating, annealing was performed in a high-temperature bath under an oxygen atmosphere at 110 ° C. for 60 minutes. Thus, an oxygen concentration measuring device for fuel cells was created.

(Oxygen concentration test of oxygen quenching paint containing water repellent and oxygen quenching paint containing no water repellent)
An oxygen-quenching paint that does not contain a water repellent (the oxygen-quenching paint A) and an oxygen-quenching paint that contains a water-repellent agent (the oxygen-quenching paint B) are applied as adherends to a glass substrate. Then, the oxygen concentration was measured using the same device as the oxygen concentration measuring device 1 described above. The measurement conditions were a temperature of 297 K and a light emission intensity ratio (Iref / I) based on a light emission intensity (Iref) of 100 kPa (Pref) when the pressure was changed to 100 kPa, 120 kPa, 160 kPa, 180 kPa, 200 kPa, 220 kPa, and 240 kPa. ) Was measured and it was confirmed that there was no effect on pressure sensitivity (P / Pref). P represents each pressure described above, and I represents the light emission intensity at each pressure.

  Even if it contains a water repellent, it does not affect the emission intensity of the oxygen-quenching paint, and there is a difference in the oxygen concentration detection sensitivity between the water-repellent-containing oxygen-quenching paint and the oxygen-quenching paint that does not contain a water repellent. There wasn't.

It is the schematic which shows an example of a structure of the oxygen concentration measuring apparatus 1 which concerns on embodiment of this invention. It is the schematic which shows an example of a structure of the oxygen concentration measuring device which concerns on other embodiment of this invention. As an example of the configuration of the light emitting section 14 formed in the oxygen gas flow path 30, a part of the oxygen gas flow path 30 as viewed from the direction of the arrow b is shown as a section cut along the arrow a in FIG. is there. It is a figure which shows the oxygen concentration measuring apparatus for fuel cells.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 Oxygen concentration measuring device, 3 Fuel cell, 10 Light irradiation part, 12 Adhering body, 14 Light emission part, 16 Light emission measurement part, 18 Processing part, 20 Control part, 22 Light emission filter, 24 MEA, 26 Oxygen gas separator, 28 hydrogen gas separator, 30 oxygen gas flow path, 32 oxygen gas inlet, 34 oxygen gas outlet.

Claims (5)

In an oxygen quenching paint containing a dye that emits light by excitation light and an oxygen permeable polymer as a binder,
An oxygen-quenching paint, wherein the oxygen-permeable polymer has a weight average molecular weight in the range of 80,000 to 300,000.   The oxygen-quenching paint according to claim 1, further comprising a water repellent. A light-emitting part in which an oxygen quenching paint including a dye that emits light by excitation light and an oxygen-permeable polymer as a binder is applied to an adherend; a light irradiation part that irradiates the light-emitting part with excitation light; and A light emission measuring unit for measuring the light emission intensity of the light emitting unit, and a processing unit for calculating an oxygen concentration from the light emission intensity of the light emitting unit measured by the light emission measuring unit,
A weight average molecular weight of the oxygen permeable polymer is in the range of 80000-300000.   4. The oxygen concentration measuring apparatus according to claim 3, wherein the oxygen quenching paint further contains a water repellent.   5. The oxygen concentration measuring apparatus according to claim 3, wherein an annealing process is performed on the light emitting portion.

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