Ultraviolet detection product and its manufacturing method

Abstract

To provide an ultraviolet detection substance that can distinguish and detect UV-C wavelength region.SOLUTION: The ultraviolet detection substance contains an oxide of aluminum, strontium, cerium, lanthanum and manganese, and an organic matter polymer, is not excited by an electromagnetic wave having a wavelength longer than 310 nm, but is excited by an electromagnetic wave having a wavelength of 310 nm or less, to emit a light having a peak of emission wavelength in 480 nm or more and 700 nm or less.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to an ultraviolet detection object and a method for producing the same. [Background technology]

[0002] Generally, ultraviolet rays refer to electromagnetic waves with a wavelength of 400 nm or less, and ultraviolet rays include UV-A with a wavelength of 315 to 400 nm, UV-B with a wavelength of 280 to 315 nm, and UV-C with a wavelength of 280 nm or less. Various methods for detecting such ultraviolet rays have been considered.

[0003] For example, ultraviolet-excited fluorescent sheets and ultraviolet-excited fluorescent inks with excellent fluorescent properties using UV-C as an excitation source can be mentioned. Specifically, ultraviolet detection objects include inorganic powder containing an inorganic phosphor that uses UV-C with a wavelength of 200 to 280 nm as an excitation source and generates fluorescence with a peak wavelength of 400 to 700 nm, and a thermoplastic resin. In this ultraviolet detection object, the inorganic phosphor contains calcium carbonate of calcite type (trigonal rhombohedral crystal) and the like (for example, see Patent Document 1).

[0004] Recently, the germicidal and virus inactivating effects of ultraviolet light have been attracting attention. Accordingly, there is a demand for accurate detection of ultraviolet light, which also has an effect on the human body. UV-C has a high germicidal and virus inactivating effect (see, for example, Non-Patent Documents 1 and 2). UV-C also has a large effect on the human body. That is, ultraviolet light with a wavelength of 200 to 300 nm has a germicidal effect, and UV-C has the highest germicidal effect. Similarly, ultraviolet light with a wavelength of 200 to 310 nm has an effect on the human body, and UV-C has the highest effect on the human body. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2018-154730 A [Non-patent literature]

[0006] [Non-Patent Document 1] Rattanakul et al, Inactivation kinetics and efficiencies of UV-LEDs against Pseudomonasaeruginosa, Legionella pneumophila, and surrogate microorganisms, Water Research 130 (2018) 31-37) [Non-Patent Document 2] Beggs et al, Upper-room ultraviolet air disinfection might help to reduce COVID-19 transmission in buildings, medRxiv preprint doi: https: / / doi.org / 10.1101 / 2020.06.12.20129254; (2020) Summary of the Invention [Problem to be solved by the invention]

[0007] However, although UV-C, which has a relatively short wavelength, has a large effect on living organisms and viruses, conventional ultraviolet detection has difficulty in detecting only UV-C because it is not possible to distinguish between different wavelength ranges of ultraviolet light. The ultraviolet detection substance described in Patent Document 1 does not state that it is excited only by UV-C, and is thought to be excited by excitation wavelengths other than UV-C.

[0008] The present invention has been made in consideration of the above points, and aims to provide an ultraviolet ray detection device that can distinguish and detect UV-C wavelength ranges. [Means for solving the problem]

[0009] The ultraviolet detection object includes a composite oxide containing aluminum, strontium, cerium, lanthanum, and manganese, and an organic polymer, The composite oxide has a crystal phase of SrAl12 O 19 The main phase is Al 2 O 3 a subphase, and cerium, lanthanum, and manganese are present in the composite oxide in a form that cannot be detected by X-ray diffraction, It cannot be excited by electromagnetic waves with wavelengths longer than 310 nm, but when excited by electromagnetic waves with wavelengths of 310 nm or less, it emits light with a peak emission wavelength between 480 nm and 700 nm. Effect of the Invention

[0010] According to the disclosed technology, it is possible to provide an ultraviolet ray detection device that can distinguish and detect the UV-C wavelength range. [Brief description of the drawings]

[0011] [Figure 1] FIG. 1 is a diagram (part 1) showing an example of characteristics of an ultraviolet ray detected object according to the present embodiment. [Diagram 2] FIG. 2 is a diagram (part 2) showing an example of characteristics of an object detected by ultraviolet light according to the embodiment. [Diagram 3] 1 is an example of an X-ray diffraction pattern of a complex oxide contained in a UV-detected object according to the present embodiment. [Figure 4] FIG. 2 is a flow diagram showing a method for producing an ultraviolet detection object according to the present embodiment. [Diagram 5] FIG. 13 is a diagram illustrating the results of the examples. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. In the drawings, the same components are denoted by the same reference numerals, and duplicated explanations may be omitted.

[0013] [UV detection object] The ultraviolet detection object according to this embodiment (hereinafter, for convenience, referred to as ultraviolet detection object 10) is a mixture of a complex oxide in which a plurality of types of oxides are combined, and an organic polymer. The complex oxide contained in the ultraviolet detection object 10 includes oxides of aluminum, strontium, cerium, lanthanum, and manganese.

[0014] The ultraviolet detection object 10 is not excited by electromagnetic waves with wavelengths longer than 310 nm, but is excited by electromagnetic waves with wavelengths of 310 nm or less to emit light with an emission wavelength peak of 480 nm or more and 700 nm or less. That is, the ultraviolet detection object 10 is not excited when irradiated with UV-A, but is excited and emits light when irradiated with UV-C. In order to facilitate excitation by UV-C, the excitation wavelength peak of the ultraviolet detection object 10 is preferably 280 nm or less. In the ultraviolet detection object 10, it is the complex oxide that contributes to the emission of light, and the organic polymer does not contribute to the emission of light.

[0015] The organic polymer contained in the ultraviolet detection object 10 preferably has an electromagnetic wave transmittance of 50 percent or more at a wavelength of 260 nm. The mixed amount (content) of the complex oxide in the ultraviolet detection object 10 is preferably 50 percent by weight or more. In other words, since organic polymers generally have low transmittance to ultraviolet light, it is preferable to select one that has high transmittance, particularly in the UV-C region of 280 nm or less, and to use as little of it as possible. In other words, it is preferable to use the minimum amount of organic polymer necessary to bind the complex oxide particles.

[0016] The difference in ultraviolet transmittance depending on the type of organic polymer is, for example, at 280 nm or less, polyvinyl butyral and polyacrylate show relatively high transmittance, while polypropylene shows slightly lower transmittance, and polystyrene, polycarbonate, polyester, and polyvinyl chloride show significantly lower transmittance. Also, plasticizer components that are often used in combination with organic polymers generally have almost no transmittance at wavelengths of 300 nm or less. Therefore, it is preferable that the ultraviolet detection object 10 does not contain a plasticizer component.

[0017] That is, for example, polyvinyl butyral resin and polyacrylate resin can be cited as organic polymers suitable for use in the ultraviolet detection object 10. When these resins are used, UV-C can be transmitted to a certain extent without significantly impeding the transmission of UV-C, so that the ultraviolet detection object 10 is excited when irradiated with UV-C and can emit light with a wavelength in the visible light region.

[0018] The organic polymer contained in the ultraviolet detection object 10 is preferably soluble in ethanol. This is because the ultraviolet detection object 10 can be easily removed when it is no longer needed. Note that polyvinyl butyral resin and polyacrylate resin are soluble in ethanol.

[0019] FIG. 1 is a diagram (part 1) showing an example of the characteristics of an ultraviolet detection object according to this embodiment, showing the emission intensity when an ultraviolet detection object 10 is excited with an electromagnetic wave having an excitation wavelength of about 265 nm. In FIG. 1, strong emission can be confirmed in the ultraviolet light region of 300 nm to 350 nm and in the visible light region of 500 nm to 550 nm (green band, peak wavelength of about 520 nm). That is, when the ultraviolet detection object 10 is irradiated with an electromagnetic wave having a wavelength of about 265 nm, it is excited and emits light with a wavelength in the visible light region (for example, green band). In FIG. 1, the two parts surrounded by dashed lines are Rayleigh scattering (measurement noise) and are not emission from the ultraviolet detection object 10.

[0020] Fig. 2 is a diagram (part 2) showing an example of the characteristics of the ultraviolet detection object according to this embodiment, showing the excitation wavelength of electromagnetic waves that can cause the ultraviolet detection object 10 to emit light at 520 nm. From Fig. 2, it can be seen that the ultraviolet detection object 10 is strongly excited by electromagnetic waves with wavelengths of 280 nm or less, and is slightly excited by electromagnetic waves with wavelengths longer than 280 nm and shorter than 310 nm. From Fig. 2, it can also be seen that the ultraviolet detection object 10 is not excited even when irradiated with electromagnetic waves with wavelengths longer than 310 nm.

[0021] In FIG. 2, the area surrounded by a dashed line is Rayleigh scattering (measurement noise) and is not the emission of the ultraviolet detection object 10. In addition, since a xenon lamp was used as a light source to measure the characteristics shown in FIG. 2, the measurement was performed with an excitation wavelength of 250 nm or more. However, judging from the shape of the short wavelength side of the spectrum shown in FIG. 2, it is thought that the ultraviolet detection object 10 is excited even with an excitation wavelength of 200 nm or more and less than 250 nm and emits light with a wavelength in the visible light region. Note that wavelengths less than 200 nm are in the region called vacuum ultraviolet, which easily absorbs oxygen and nitrogen, so there is little need to discuss the bactericidal effect, virus inactivation effect, effects on the human body, etc. Therefore, in this application, it is sufficient to consider wavelengths of 200 nm or more.

[0022] The ultraviolet detection object 10 may be excited by electromagnetic waves with a wavelength of 310 nm or less and emit light with an emission wavelength peak of 480 nm or more and 700 nm or less, and the emission wavelength peak may be in a range other than 500 nm to 550 nm.

[0023] 3 is an example of an X-ray diffraction pattern of a complex oxide contained in the ultraviolet detection object according to the present embodiment. As shown in FIG. 3, the ultraviolet detection object 10 has a crystalline phase of SrAl 12 O 19 The main phase is Al2O3 (hexagonal system) and the subphase is Al2O3 (corundum). Ce, La, and Mn have not been detected by X-ray diffraction. In other words, Ce, La, and Mn exist in the composite oxide in a form that cannot be detected by X-ray diffraction.

[0024] During firing, strontium reacts with aluminum oxide to form the main phase of the composite oxide, SrAl 12 O 19 During firing, aluminum reacts with strontium carbonate or its decarbonated oxide to form the main phase of the composite oxide, SrAl 12 O 19 It is believed that the corundum phase is stable and acts as a host for the luminescent element and exists as a single corundum phase.

[0025] [Method of manufacturing ultraviolet detection products] Fig. 4 is a flow diagram showing a method for producing an ultraviolet detection object according to the present embodiment. As shown in Fig. 4, in order to produce an ultraviolet detection object 10, first, in step S101, powders of a plurality of oxides including aluminum, strontium, cerium, lanthanum, and manganese are dry-mixed. For example, aluminum oxide powder, strontium carbonate powder, cerium oxide powder, and lanthanum strontium manganese oxide powder are dry-mixed.

[0026] Next, in step S102, the powder of the oxides dry-mixed in step S101 is molded into a predetermined shape and sintered in air at a temperature of 1200°C or higher (for example, 1500°C). This produces a sintered body of a composite oxide containing the oxides. The main phase of the crystal phase of the sintered body produced in step S102 is SrAl 12 O 19 In addition, if the material is fired at a temperature below 1200°C, the yield of ultraviolet detection material capable of distinguishing and detecting the UV-C wavelength range is significantly reduced.

[0027] Next, in step S103, the sintered body produced in step S102 is pulverized to produce a powder of the complex oxide. For example, a general-purpose pulverizer can be used for pulverization. The average particle size of the powder of the complex oxide can be controlled by adjusting the pulverization conditions of the pulverizer. In order to stably emit visible light when irradiated with UV-C, the average particle size of the powder of the complex oxide is preferably 100 μm or more. On the other hand, from the viewpoint of coating, printing, and moldability, the average particle size of the powder of the complex oxide is preferably 500 μm or less. The average particle size can be measured by a method using a normal particle size distribution measuring device or a method of determining the particle settling velocity in a liquid medium using Stokes' law.

[0028] Next, in step S104, an organic polymer powder is prepared, and the composite oxide powder and the organic polymer powder are mixed to prepare a mixture A. The organic polymer used in step S104 is, for example, a polyvinyl butyral resin or a polyacrylate resin.

[0029] Next, in step S105, a predetermined solvent (such as ethanol) is added to the mixture A produced in step S104 to dissolve and knead the organic polymer components, thereby producing a liquid or paste-like mixture B. The produced mixture B is the ultraviolet detection object 10. The amount (content) of the composite oxide in the mixture B is preferably 50 weight percent or more.

[0030] Examples will be described below, but the present invention is not limited to these examples in any way.

[0031] [Example 1] 100 parts by weight of aluminum oxide powder, 12 parts by weight of strontium carbonate powder, 2.3 parts by weight of cerium oxide powder, and 2.3 parts by weight of lanthanum strontium manganese oxide powder were dry mixed and then fired in air at 1500°C for 10 hours to obtain a sintered body. The molar concentrations of each oxide component were 89.4 mol percent Al2O3, 7.6 mol percent SrO, 1.2 mol percent CeO2, 0.8 mol percent La2O3, and 1.0 mol percent MnO2.

[0032] The molar concentration of each oxide component is calculated from the weight. Strontium carbonate powder changes to SrO when fired. Lanthanum strontium manganese oxide powder changes to La2O3, SrO, and MnO2 when fired.

[0033] Next, the sintered body was pulverized to prepare a composite oxide powder. The composite oxide powder thus prepared had an average particle size of 100 μm or more and 500 μm or less. Then, 100 parts by weight of the composite oxide powder and 10 parts by weight of polyvinyl butyral resin powder were mixed, and ethyl alcohol was added to dissolve and knead the resin component to prepare a paste-like ultraviolet detection object 10A.

[0034] [Example 2] 100 parts by weight of a composite oxide powder prepared in the same manner as in Example 1 was mixed with 10 parts by weight of a polymethyl acrylate resin powder, and ethyl acetate was added to dissolve and knead the resin components to produce a paste-like ultraviolet detection material 10B.

[0035] [Checking the light emission] The paste-like ultraviolet detection material 10A prepared in Example 1 and the paste-like ultraviolet detection material 10B prepared in Example 2 were printed on a polyethylene terephthalate film and dried. For reference, Fig. 5(a) shows the state of the dried ultraviolet detection materials 10A and 10B irradiated with a fluorescent lamp.

[0036] Next, the dried ultraviolet detection objects 10A and 10B were sequentially irradiated with ultraviolet light of wavelengths of 365 nm and 254 nm using an ultraviolet exposure device, and the presence or absence of luminescence was confirmed. As a result, in both the ultraviolet detection object 10A prepared in Example 1 and the ultraviolet detection object 10B prepared in Example 2, no luminescence was observed at an excitation wavelength of 365 nm, and strong green-white luminescence was confirmed at an excitation wavelength of 254 nm, as shown in Figure 5 (b). Note that 365 nm is ultraviolet light belonging to UV-A, and 254 nm is ultraviolet light belonging to UV-C.

[0037] Thus, the ultraviolet detection objects 10A and 10B according to Examples 1 and 2 emitted light in different light emission modes under irradiation with UV-A and UV-C, respectively. That is, although they did not emit light under irradiation with UV-A, they emitted light strongly under irradiation with UV-C. Therefore, by using the ultraviolet detection objects 10A and 10B according to Examples 1 and 2, it is possible to detect the presence or absence of irradiation with UV-C.

[0038] The molar concentrations of the oxide components of the composite oxides shown in Examples 1 and 2 are merely examples. The molar concentrations of the oxide components can be changed as appropriate, for example, the molar concentration of aluminum oxide may be changed within the ranges of 84.9 to 93.8 molar percent, the molar concentration of strontium oxide may be changed within the ranges of 7.2 to 8.0 molar percent, the molar concentration of cerium oxide may be changed within the ranges of 1.1 to 1.3 molar percent, the molar concentration of lanthanum oxide may be changed within the ranges of 0.8 to 0.9 molar percent, and the molar concentration of manganese oxide may be changed within the ranges of 1.0 to 1.1 molar percent.

[0039] As described above, the ultraviolet detection object according to the present embodiment includes a composite oxide containing aluminum, strontium, cerium, lanthanum, and manganese, and an organic polymer, and is not excited by electromagnetic waves with wavelengths longer than 310 nm, but is excited by electromagnetic waves with wavelengths of 310 nm or less to emit light with a peak emission wavelength of 480 nm to 700 nm. Therefore, the presence or absence of irradiation and the reach of UV-C, which has a large impact on living organisms and viruses, can be visually confirmed by the emission of wavelengths in the visible light region, and the wavelength range of ultraviolet light can be distinguished and detected.

[0040] In addition, the ultraviolet detection product according to the present embodiment does not require energy supply for UV-C detection, and can quickly and easily detect UV-C at low cost. In addition, the ultraviolet detection product according to the present embodiment can be mixed with an organic polymer to be molded into a specific shape or applied to a test object or a test site, improving the flexibility of usage.

[0041] On the other hand, even organic polymers that exhibit relatively high UV transmittance will lose transmittance and mechanical strength when exposed to UV for a long period of time. Therefore, it is preferable that the UV detection object according to the present embodiment is used in a state that allows quick and easy detection of the UV-C region and is easy to replace, rather than being used for a long period of time in a fixed manner.

[0042] A specific example of use is to form the ultraviolet detection material according to this embodiment into a film, provide an adhesive layer, and attach it to a test object or a test site, and peel it off after detecting UV-C (checking arrival and generation, etc.). Alternatively, the ultraviolet detection material according to this embodiment is applied to a test object or a test site in a liquid or paste form, and wiped off with alcohol or the like after detecting UV-C. To realize the latter method of use, it is preferable that the organic polymer used is one that dissolves in alcohol, and polyvinyl alcohol, polyvinyl butyral, etc. are preferably used.

[0043] Although preferred embodiments have been described above in detail, the present invention is not limited to the above-described embodiments, and various modifications and substitutions can be made to the above-described embodiments without departing from the scope of the claims. [Explanation of symbols]

[0044] 10A, 10B UV detection object

Claims

1. The present invention includes a composite oxide containing aluminum, strontium, cerium, lanthanum, and manganese, and an organic polymer, The composite oxide has a crystal phase in which SrAl 12 O 19 is a main phase and Al 2 O 3 is a subphase, Cerium, lanthanum, and manganese are present in the composite oxide in a form that cannot be detected by X-ray diffraction, An ultraviolet detection object which is not excited by electromagnetic waves having a wavelength longer than 310 nm, but is excited by electromagnetic waves having a wavelength of 310 nm or less and emits light having an emission wavelength peak in the range of 480 nm to 700 nm.

2. The ultraviolet detection object according to claim 1 , wherein the excitation wavelength peak is 280 nm or less.

3. 3. The ultraviolet detection object according to claim 1, wherein the organic polymer has a transmittance of 50 percent or more for electromagnetic waves having a wavelength of 260 nm.

4. The ultraviolet detection device according to claim 1 , wherein the content of the complex oxide is 50 weight percent or more.

5. The ultraviolet detection device according to claim 1 , wherein the organic polymer is soluble in ethanol.

6. 6. The ultraviolet detection device according to claim 1, wherein the organic polymer is a polyvinyl butyral resin or a polyacrylate resin.

7. The ultraviolet detection object according to claim 1 , wherein the composite oxide has an average particle size of 100 μm or more.

8. A step of preparing a powder of a composite oxide containing aluminum, strontium, cerium, lanthanum, and manganese; preparing a mixture of the composite oxide powder and an organic polymer powder; and adding a solvent to the mixture and kneading the mixture. The step of preparing the composite oxide powder includes: A step of mixing powders of a plurality of oxides including aluminum, strontium, cerium, lanthanum, and manganese, and sintering the mixture at a temperature of 1200° C. or higher in the atmosphere to prepare a sintered body of the composite oxide; and pulverizing the sintered body to produce a powder of the composite oxide. The composite oxide has a crystal phase in which SrAl 12 O 19 is a main phase and Al 2 O 3 is a subphase, Cerium, lanthanum, and manganese are present in the composite oxide in a form that cannot be detected by X-ray diffraction, A method for producing an ultraviolet detection object which is not excited by electromagnetic waves having a wavelength longer than 310 nm, but is excited by electromagnetic waves having a wavelength of 310 nm or less and emits light having an emission wavelength peak of 480 nm or more and 700 nm or less.

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