JP7578652B2 - Phosphine detector - Google Patents

Description

The present invention relates to a phosphine detector.

Fumigation with phosphine _PH3 is widely carried out in warehouses, on ships, and inside equipment to eliminate pests. For example, fumigation on a cargo ship usually involves exposing the cargo to a prescribed amount of phosphine for several days or more with the cargo holds closed.

However, because phosphine is harmful to humans, it is necessary to detect phosphine in the environment. Traditionally, detection of phosphine in the environment has been carried out using gas measurement devices equipped with gas detection mechanisms such as electrically powered sensors, and gas detector tubes. When using gas detector tubes, detection is carried out using gas samples that are intermittently drawn in from the environment either manually or electrically.

Patent Document 1 discloses a gas measurement device that uses detection paper carrying a reagent that reacts with multiple types of measurement gases, such as phosphine, to produce a reaction mark that changes in optical density. This gas measurement device can measure the types and concentrations of multiple types of measurement gases.

JP 2015-232532 A

In recent years, it has become desirable to know the level of past phosphine exposure for each item that has been subjected to fumigation. In order to detect the level of past phosphine exposure, it is preferable to be able to constantly detect the phosphine exposure concentration for each item. Furthermore, in order to constantly detect the phosphine exposure concentration for many items loaded onto cargo ships, etc., a detector that does not require human intervention is required.

However, the gas measuring device of Patent Document 1 requires electricity. For this reason, it is difficult for the gas measuring device of Patent Document 1 to constantly detect the phosphine exposure concentration of small individual items, and there is also the problem that the cost of constant detection is high. In addition, gas detection tubes intermittently aspirate and detect gas samples, so there is a problem that they cannot constantly detect the phosphine exposure concentration.

The present invention was made in consideration of the problems inherent in the conventional technology. The object of the present invention is to provide a highly responsive phosphine detector that can continuously detect phosphine without power consumption.

The phosphine detector according to this embodiment of the present invention comprises a support and a phosphine detector section supported on the surface of the support and comprising a mixture of a plurality of basic copper carbonate particles and a plurality of cellulose fibers, the average length of the plurality of cellulose fibers being 0.8 mm or more and 2 mm or less, and the phosphine detector section being substantially free of a binder.

The present invention provides a highly responsive phosphine detector that can continuously detect phosphine without power consumption.

FIG. 1 is a schematic plan view showing an example of a phosphine detection element according to an embodiment of the present invention. 2 is a schematic cross-sectional view of the phosphine detector according to the present embodiment taken along line II-II in FIG. 1. FIG. 2 is a schematic cross-sectional view showing an example of a state in which a support and a phosphine detection unit are packaged in a packaging material. This shows the results of evaluating the response to phosphine exposure depending on the type of cellulose fiber in the phosphine detection part. This shows the results of evaluating the response to phosphine exposure due to differences in the cellulose content of the phosphine detection part. This shows the results of comparing the phosphine detectors according to Examples 2 to 6 before exposure and after 24 hours of exposure. This shows the results of evaluating the responsiveness to phosphine exposure depending on whether or not the phosphine detection unit has a binder.

The phosphine detector according to this embodiment will be described in detail below with reference to the drawings. Note that the dimensional ratios in the drawings are exaggerated for the convenience of explanation and may differ from the actual ratios.

[Phosphine detector]
Fig. 1 is a plan view of a phosphine detection element 1 according to this embodiment. Fig. 2 is a cross-sectional view of the phosphine detection element 1 according to this embodiment taken along line II-II in Fig. 1. As shown in Figs. 1 and 2, the phosphine detection element 1 comprises a support 10 and a phosphine detection section 20 supported on the surface of the support 10.

(Support)
The support 10 supports the phosphine detection unit 20. The material of the support 10 is not particularly limited, and may include, for example, at least one material selected from the group consisting of paper, plastic, metal, ceramics, and wood. The support 10 may be capable of supporting the phosphine detection unit 20 at least on the surface of the support 10. For this reason, the phosphine detection unit 20 may be formed inside the support 10 in addition to on the surface of the support 10 by impregnating the inside of the support 10 with a detection ink described below.

The support 10 may be a porous body having at least one of communicating pores and through pores. The communicating pores are pores in which adjacent pores are connected to each other and communicate with the outside of the support 10. The through pores are pores that connect from one surface to the other surface. When the support 10 has a plate-like structure, for example, the support 10 may have a plurality of pores that communicate from the front surface to the back surface of the plate-like structure. Also, when the support 10 is a hexahedron such as a rectangular parallelepiped, the support 10 may have a plurality of pores that communicate from one surface to the surface opposite the one surface. Since the porous body has communicating pores or through pores, when the phosphine detection body 1 is exposed to phosphine, the contact area of the phosphine detection unit 20 with phosphine increases. Therefore, the reactivity of the phosphine detection unit 20 can be improved.

The support 10 may be, for example, paper. Paper is carbon neutral and can reduce carbon dioxide emissions into the atmosphere. In addition, paper is inexpensive and flammable, so it can be easily disposed of together with other constituent materials.

The support 10 may be filter paper. By using filter paper as the support 10, the phosphine detection unit 20 can be easily formed, as described below.

The shape of the support 10 is not particularly limited as long as it can support the phosphine detection unit 20. Examples of the shape of the support 10 include a flat plate, a curved plate, and a polygonal prism such as a cube or a rectangular parallelepiped.

When the support 10 is a flat plate, the thickness of the support 10 may be 0.1 mm or more and 5 mm or less. When the thickness of the support 10 is within the above range, it is easy to handle as a phosphine detector 1. The thickness of the support 10 may be 0.2 mm or more. In addition, the thickness of the support 10 may be 2 mm or less, 1 mm or less, or 0.5 mm or less.

(Phosphine detection unit)
The phosphine detection unit 20 includes a plurality of basic copper carbonate particles and a plurality of cellulose fibers. The basic copper carbonate particles and the cellulose fibers are mixed together. In the phosphine detection unit 20, each of the plurality of cellulose fibers may form a gap between the cellulose fibers. Furthermore, each of the plurality of basic copper carbonate particles may be disposed between each of the plurality of cellulose fibers.

<Basic copper carbonate particles>
Basic copper carbonate is reactive to phosphine and is chemically stable when exposed to substances other than phosphine. Specifically, basic copper carbonate is less likely to discolor due to temperature and humidity compared to copper acetate. Also, basic copper carbonate is not excessively reactive compared to silver acetate. More specifically, silver acetate can detect phosphine at a low concentration such as 1 ppm, but is prone to discoloration due to temperature, humidity and light, making it difficult to determine whether it is exposed to a concentration such as 100 ppm. On the other hand, basic copper carbonate has different reactivity depending on the exposure concentration and exposure time of phosphine. Therefore, by using basic copper carbonate, a phosphine detection unit 20 can be formed in which the reactivity to the exposure concentration and exposure time of phosphine is controlled.

The basic copper carbonate may contain Cu(OH) _{2.CuCO 3} , also known as malachite. Cu(OH) _{2.CuCO 3} has the property of being green before exposure to phosphine, and turning black when reduced by exposure to phosphine. It is presumed that the color of Cu(OH) _{2.CuCO 3} changes to black due to Cu, which is a reaction product of Cu(OH) _{2.CuCO 3} and phosphine, as shown in the following reaction formula (1). Note that the by-product of the following reaction formula (1) contains, for example, a solid derived from phosphoric acid.

2Cu(OH) _{2.CuCO 3} +PH ₃ →Cu+byproduct (1)

In addition, copper phosphate and copper oxide (Cu ₂ O) produced due to the reaction of 2Cu(OH) _{2.CuCO 3} with phosphine also react with phosphine to produce black reaction products.

Gaps may exist between the multiple basic copper carbonate particles contained in the phosphine detection unit 20. The average particle diameter of the basic copper carbonate particles is not particularly limited, but may be smaller than the average fiber diameter of the cellulose fibers. In such a case, the cellulose fibers can form appropriate gaps, so that the reactivity of the phosphine detection unit 20 can be maintained at a good level.

Specifically, the average particle diameter of the basic copper carbonate particles may be 0.01 μm or more and 20 μm or less. When the average particle diameter is 0.01 μm or more, the basic copper carbonate particles fill the gaps between the fibers, and the internal basic copper carbonate particles can be prevented from being less exposed to phosphine. When the average particle diameter is 20 μm or less, the specific surface area of the basic copper carbonate particles increases, and the reactivity increases. In addition, since the cellulose fibers can form appropriate gaps, the reactivity of the phosphine detection unit 20 can be maintained at a good level. The average particle diameter of the basic copper carbonate particles may be 0.05 μm or more, or may be 0.1 μm or more. In addition, the average particle diameter of the basic copper carbonate particles may be 10 μm or less, 5 μm or less, or 2 μm or less. In this specification, unless otherwise specified, the value of "average particle size" is the value calculated as the average particle size of particles observed in several to several tens of fields of view using an observation means such as a scanning electron microscope (SEM) or a transmission electron microscope (TEM).

The content of the basic copper carbonate particles may be 7% by mass or more and 60% by mass or less with respect to the phosphine detection unit 20. By making the content of the basic copper carbonate particles 7% by mass or more, the responsiveness of the phosphine detection unit 20 becomes higher. Furthermore, by making the content of the basic copper carbonate particles 60% by mass or less, the collapse of the phosphine detection unit 20 can be suppressed. The content of the basic copper carbonate particles may be 15% by mass or more, 30% by mass or more, 40% by mass or more, or 45% by mass or more. Furthermore, the content of the basic copper carbonate particles may be 55% by mass or less, or 50% by mass or less.

The shape of the basic copper carbonate particles is not particularly limited, and may be at least one shape selected from the group consisting of needle-like, angular, dendritic, fibrous, flaky, irregular, teardrop-like, and spherical.

The specific surface area of the multiple basic copper carbonate particles is not particularly limited. The larger the specific surface area, the higher the reaction responsiveness tends to be.

<Cellulose fiber>
The cellulose fibers are entangled to form gaps between the cellulose fibers. The gaps improve the air permeability, so that when the phosphine detection unit 20 is exposed to phosphine, the phosphine easily comes into contact with the basic copper carbonate particles. The cellulose fibers can also support the basic copper carbonate particles.

Cellulose fibers can reduce carbon dioxide emissions into the atmosphere from the perspective of carbon neutrality. In addition, cellulose fibers are industrially produced in various sizes, so they can be obtained cheaply, and can be selected according to the purpose, such as controlling the reactivity due to voids, making them easy to form into films and mold. Cellulose fibers are also safer than carbon nanofibers and ceramic fibers, and there is no need to worry about their effects on the respiratory system, so they can be handled safely during production and use. Cellulose fibers are also flammable and easy to dispose of, and basic copper carbonate is also easily disposed of together with copper oxide (II), carbon dioxide, and water at 220°C. Furthermore, cellulose fibers are less likely to have a negative effect on reactivity.

The average length of the multiple cellulose fibers is 0.8 mm or more and 2 mm or less. When the average length of the cellulose fibers is 0.8 mm or more, the cellulose fibers are entangled with each other, and the phosphine detection unit 20 is easily self-supporting. Therefore, the phosphine detection unit 20 is less likely to collapse even if it does not contain a binder. Furthermore, when the average length of the cellulose fibers is 2 mm or less, the fibers are easily unraveled when preparing the detection ink, and the phosphine detection unit 20 can be easily formed. The average length of the cellulose fibers may be 0.9 mm or more, or may be 1 mm or more. Furthermore, the average length of the cellulose fibers may be 1.5 mm or less, or may be 1.2 mm or less.

The average fiber diameter of the multiple cellulose fibers may be larger than the average particle diameter of the basic copper carbonate particles. With this configuration, an appropriate amount of voids are formed within the phosphine detection unit 20, and when the phosphine detection body 1 is exposed to phosphine, the basic copper carbonate particles are more likely to react with phosphine.

The average fiber diameter of the multiple cellulose fibers may be 15 μm or more and 50 μm or less. When the average fiber diameter of the cellulose fibers is 15 μm or more, appropriate gaps are formed, and the reactivity of the phosphine detection unit 20 becomes higher. Furthermore, when the average fiber diameter of the cellulose fibers is 50 μm or less, the basic copper carbonate particles are closer to each other, and the visibility of discoloration in the phosphine detection unit 20 may be increased. The average fiber diameter of the cellulose fibers may be 18 μm or more, or 20 μm or more. Furthermore, the average fiber diameter of the cellulose fibers may be 40 μm or less, 30 μm or less, or 25 μm or less.

The average length of the cellulose fibers relative to the average fiber diameter (aspect ratio) may be 15 or more and 100 or less. When the aspect ratio is 15 or more, the cellulose fibers are entangled with each other, and the phosphine detection unit 20 is self-supporting. Therefore, the phosphine detection unit 20 is less likely to collapse even if it does not contain a binder. Furthermore, when the aspect ratio is 100 or less, the phosphine detection unit 20 can be easily formed because it is easily loosened when preparing the detection ink. The aspect ratio may be 20 or more, 30 or more, or 40 or more. Furthermore, the aspect ratio may be 90 or less, 80 or less, 70 or less, or 60 or less.

Unless otherwise specified, the average length and average fiber diameter of multiple cellulose fibers are calculated as the average length or diameter of cellulose fibers observed in several to several tens of fields of view using an observation method such as a scanning electron microscope (SEM) or a transmission electron microscope (TEM).

The content of cellulose fiber may be 40% by mass or more and 93% by mass or less with respect to the phosphine detection unit 20. By making the content of cellulose fiber 40% by mass or more, it is possible to suppress the collapse of the phosphine detection unit 20. Furthermore, by making the content of cellulose fiber 93% by mass or less, the responsiveness of the phosphine detection unit 20 becomes higher. The content of cellulose fiber may be 45% by mass or more, or may be 50% by mass or more. Furthermore, the content of cellulose fiber may be 85% by mass or less, 70% by mass or less, 60% by mass or less, or 55% by mass or less.

The phosphine detection unit 20 does not substantially contain a binder. In the phosphine detection unit 20 according to this embodiment, the average length of the cellulose fibers is long, so that the cellulose fibers are entangled with each other and the phosphine detection unit 20 stands on its own. Therefore, the phosphine detection unit 20 is not easily broken even if it does not contain a binder. When the phosphine detection unit 20 does not substantially contain a binder, the basic copper carbonate particles are easily exposed to phosphine, and the reactivity of the phosphine detection unit 20 is improved. When the phosphine detection unit 20 does not substantially contain a binder, it means that the binder content of the phosphine detection unit 20 is 1% by mass or less. The binder content may be 0.5% by mass or less, or may be 0% by mass.

The binder here means a binder that binds the basic copper carbonate particles and the cellulose fibers. The material of the binder is not particularly limited, but an organic binder may be used. The binder may contain, for example, at least one of a resin and a cellulose nanofiber. The resin used in the binder may contain at least one selected from the group consisting of an acrylic resin, an epoxy resin, a vinyl resin, and a cellulose resin. An example of the cellulose resin is hydroxyethyl cellulose.

As shown in Figures 1 and 2, the phosphine detection unit 20 of the phosphine detection body 1 has a trapezoidal cross-sectional shape. However, the phosphine detection unit 20 of this embodiment may have a cross-sectional shape other than a trapezoid, for example, a rectangular shape. The phosphine detection unit 20 may also be shaped like a barcode or a QR code (registered trademark).

The thickness of the phosphine detection unit 20 may be 20 μm or more and 200 μm or less. When the thickness of the phosphine detection unit 20 is 20 μm or more, the color of the phosphine detection unit 20 can be clearly confirmed. Furthermore, when the thickness of the phosphine detection unit 20 is 200 μm or less, cracks are less likely to occur on the surface of the phosphine detection unit 20, and unevenness in the reaction of the phosphine detection unit 20 can be suppressed. The thickness of the phosphine detection unit 20 may be 50 μm or more, or may be 80 μm or more. Furthermore, the thickness of the phosphine detection unit 20 may be 160 μm or less, or may be 120 μm or less.

As shown in FIG. 3, the phosphine detector 1 may further include a packaging material 30 having breathability. The phosphine detector 20 supported on the support 10 may be packaged in the packaging material 30. The phosphine detector 1 according to this embodiment is unlikely to crumble even if the phosphine detector 20 does not substantially contain a binder, but it is expected that some of the basic copper carbonate particles and cellulose fibers of the phosphine detector 20 may scatter. Therefore, by packaging the phosphine detector 20 supported on the support 10 in the packaging material 30 having breathability, it is possible to prevent these particles from scattering. An example of the packaging material 30 having breathability is a sterilized bag.

The sterilization bag may, for example, comprise a resin film 31 and sterilized paper 32. With the phosphine detector 1 disposed between the resin film 31 and the sterilized paper 32, the periphery of the resin film 31 and the sterilized paper 32 are pasted together, so that the phosphine detector 20 supported on the support 10 can be contained within the sterilization bag. The resin film 31 may contain at least one thermoplastic resin selected from the group consisting of polyethylene terephthalate, polypropylene, and polyethylene. The sterilized paper 32 is, for example, paper that is permeable to phosphine but not to bacteria.

The phosphine detector 1 is placed on the surface of or within the object to be measured, which is to be the subject of measurement of exposure to phosphine. When placing the phosphine detector 1 on the surface of or within the object to be measured, it may simply be placed on the object, or it may be attached using an adhesive, adhesive tape, etc.

Next, the action of the phosphine detector 1 will be described. The phosphine detector 20 of the phosphine detector 1 changes color before and after exposure to a predetermined amount of phosphine. For example, basic copper carbonate Cu(OH) _2.CuCO3 contained in the phosphine detector ₂₀ has the property of being green before exposure to phosphine and changing color to black when reduced by exposure to phosphine.

The discoloration of the phosphine detection unit 20 maintains the color after discoloration once it has changed color. Therefore, the phosphine detection body 1 can detect the level of the phosphine exposure concentration in the past. The discoloration of the phosphine detection unit 20 can be detected visually or by machine to determine the degree of discoloration. Furthermore, since the discoloration is based on the reduction of basic copper carbonate by phosphine, it occurs without electricity. Furthermore, since the above action occurs without electricity, phosphine exposure can be detected at all times. Furthermore, since the discoloration occurs only in the phosphine detection body 1, the phosphine detection body 1 can be made smaller within the range in which the discoloration can be detected.

As described above, the phosphine detector 1 according to this embodiment includes a support 10 and a phosphine detector section 20 that is supported on the surface of the support 10 and contains a mixture of a plurality of basic copper carbonate particles and a plurality of cellulose fibers. The average length of the plurality of cellulose fibers is 0.8 mm or more and 2 mm or less. The phosphine detector section 20 does not substantially contain a binder.

According to the phosphine detector 1, the color of the phosphine detector 20 changes before and after exposure to a predetermined amount of phosphine. Therefore, the phosphine detector 1 is small, does not require electricity, and can constantly detect phosphine.

The average length of the multiple cellulose fibers is 0.8 mm or more and 2 mm or less, and the phosphine detection unit 20 does not substantially contain a binder. Therefore, the cellulose fibers are entangled with each other to make the phosphine detection unit 20 self-supporting. Therefore, the phosphine detection unit 20 is not easily broken down even if it does not contain a binder. Furthermore, when the phosphine detection unit 20 does not substantially contain a binder, the basic copper carbonate particles are easily exposed to phosphine, and the reactivity of the phosphine detection unit 20 is improved.

Note that basic copper carbonate is an insulator, and when it reacts with phosphine, copper, which is a conductor, is produced from basic copper carbonate. Therefore, it may be possible to electrically detect copper. For example, by incorporating the phosphine detector 1 into an RFID (radio frequency identifier), it may be possible to detect it remotely.

[Method of manufacturing phosphine detector]
Next, a method for producing the phosphine detection element 1 according to this embodiment will be described. The phosphine detection element 1 can be obtained by forming a phosphine detection unit 20 on the surface of a support 10. Specifically, the phosphine detection element 1 according to this embodiment may include a step of preparing a detection ink, a step of applying the detection ink to the support 10, and a step of removing the dispersion liquid.

In the process of preparing the detection ink, a detection ink containing basic copper carbonate particles, cellulose fibers, and a dispersion liquid is prepared. The detection ink can be obtained by mixing the basic copper carbonate particles, cellulose fibers, and the dispersion liquid by stirring or the like. The basic copper carbonate particles and cellulose fibers can be those described above. As the dispersion liquid, for example, an inorganic solvent such as water or an organic solvent such as alcohol is used. Among these, it is preferable to use water as the dispersion liquid from the viewpoint of environmental consideration.

In the step of applying the detection ink to the support 10, the ink prepared in the step of preparing the detection ink is applied to the support 10. The method of applying the detection ink to the support 10 is not particularly limited, and the detection ink can be applied, for example, by dripping, coating, spraying, printing, or a combination of these. Examples of dripping include dripping onto the support 10 using a dropper or pipette. Examples of coating include coating using a bar coater. Examples of printing include screen printing, toner printing, inkjet printing, letterpress printing, intaglio printing, or a combination of these.

In the step of removing the dispersion liquid, the dispersion liquid is removed from the detection ink applied to the support 10. By removing the dispersion liquid from the detection ink, a phosphine detection unit 20 containing a plurality of basic copper carbonate particles and a plurality of cellulose fibers is formed. Methods for removing the dispersion liquid include filtration such as suction filtration, natural drying at room temperature, drying by heating, and combinations of these. Among these, filtration is preferred because it can remove water-soluble foreign matter contained in the raw material of the plurality of basic copper carbonate particles from the detection ink.

According to the method described above, it is possible to manufacture a phosphine detector 1 having the above-mentioned support 10 and phosphine detector 20.

The present embodiment will be described in more detail below with reference to examples and comparative examples, but the present embodiment is not limited to these examples.

The following materials were prepared as raw materials for the detection inks of the Examples and Comparative Examples.
(1) Basic copper carbonate particles Cu(OH) _2.CuCO3 (Kanto Chemical Co., Ltd., copper(II) carbonate (basic), 2N5), average particle size 1 _μm
(2) Cellulose fiber (2-1) Pulp P
MZ Pulp PF-00-004 (Arts & Crafts), fiber diameter 20 μm, fiber length 1 mm
(2-2) Pulp PP06
NP Fiber W-06MG (Nippon Paper Industries Co., Ltd.), fiber diameter 6 μm, fiber length 6 μm
(2-3) Pulp PP24
KC Flock (registered trademark) W-400G (Nippon Paper Industries Co., Ltd.), fiber diameter 24 μm, fiber length 40 μm
(2-4) Pulp VP50
VP-1 50μ (TDI Corporation), fiber diameter 10μm to 20μm, fiber length 50μm
(2-5) Pulp VP100
VP-1 100μ (TDI Corporation), fiber diameter 10μm to 20μm, fiber length 100μm
(2-6) Pulp ST02
Ceolus (registered trademark) ST-02 (Asahi Kasei Corporation), fiber diameter 40 μm, fiber length 100 μm
(2-7) Pulp ST100
Ceolus (registered trademark) ST-100 (Asahi Kasei Corporation), fiber diameter 20 μm, fiber length 200 μm
(3) Water: Ion-exchanged water (electrical conductivity 0.1 μS/cm)

[Example 1]
First, 1% by mass of basic copper carbonate particles, 1% by mass of cellulose fiber, and 98% by mass of water were mixed and stirred for 1 hour to prepare a detection ink. Pulp P was used as the cellulose fiber.

Next, the collected detection ink was dropped onto a filter paper (Advantec, quantitative filter paper No. 3, Φ55 mm) (support) set in a suction filter. This detection ink was filtered by suction, and a phosphine detection part containing 50% by mass of basic copper carbonate particles and 50% by mass of cellulose fibers and having a film thickness of approximately 100 μm was formed on the filter paper. This was cut and enclosed in a breathable sterile bag (Medicom, sterile roll bag, width 50 mm, ASKJR75010) to produce a phosphine detection element.

[Comparative Example 1]
A phosphine detector was prepared in the same manner as in Example 1, except that pulp P06 was used as the cellulose fiber.

[Comparative Example 2]
A phosphine detector was prepared in the same manner as in Example 1, except that PP24 pulp was used as the cellulose fiber.

[Comparative Example 3]
A phosphine detector was prepared in the same manner as in Example 1, except that pulp VP50 was used as the cellulose fiber.

[Comparative Example 4]
A phosphine detector was prepared in the same manner as in Example 1, except that pulp VP100 was used as the cellulose fiber.

[Comparative Example 5]
A phosphine detector was prepared in the same manner as in Example 1, except that pulp ST02 was used as the cellulose fiber.

[Comparative Example 6]
A phosphine detector was prepared in the same manner as in Example 1, except that pulp ST100 was used as the cellulose fiber.

[evaluation]
(Fumigation test)
First, a 100 L acrylic chamber was prepared in a laboratory set at about 25° C. Next, the phosphine detector obtained as described above was placed in the 100 L acrylic chamber. Next, while checking the concentration with a gas detector tube, phosphine standard gas was continuously injected into the acrylic chamber so that the phosphine concentration in the acrylic chamber was 100 ppm. Then, photographs of the phosphine detector were taken at predetermined time intervals. The results are shown in FIG. 4.

As shown in Figure 4, all of the phosphine detectors changed color from green to black, and were able to detect phosphine in a short time. However, in the phosphine detectors of Comparative Examples 1 to 6, which used cellulose fibers with an average length of 100 μm or less, the phosphine detection section collapsed upon light impact. On the other hand, in the phosphine detector of Example 1, which used cellulose fibers with an average length of 1 mm, the phosphine detection section did not collapse upon light impact.

Next, the following examples were prepared to evaluate the content dependence of basic copper carbonate particles.

[Example 2]
First, 1% by mass of basic copper carbonate particles, 1% by mass of cellulose fiber, and 98% by mass of water were mixed and stirred for 1 hour to prepare a detection ink. Pulp PP06 was used as the cellulose fiber.

Next, the collected detection ink was dropped onto a filter paper (Advantec, quantitative filter paper No. 3, Φ55 mm) (support) set in a suction filter. This detection ink was filtered by suction, and a phosphine detection part containing 50% by mass of basic copper carbonate particles and 50% by mass of cellulose fibers and having a film thickness of approximately 100 μm was formed on the filter paper. This was cut and enclosed in a breathable sterile bag (Medicom, sterile roll bag, width 50 mm, ASKJR75010) to produce a phosphine detection element.

[Example 3]
A phosphine detector was prepared in the same manner as in Example 2, except that the phosphine detector contained 20 mass % basic copper carbonate particles and 80 mass % cellulose fibers.

[Example 4]
A phosphine detector was prepared in the same manner as in Example 2, except that the phosphine detector contained 10 mass % basic copper carbonate particles and 90 mass % cellulose fibers.

[Example 5]
A phosphine detector was prepared in the same manner as in Example 2, except that the phosphine detector contained 5% by mass of basic copper carbonate particles and 95% by mass of cellulose fibers.

[Example 6]
A phosphine detector was prepared in the same manner as in Example 2, except that the phosphine detector contained 2 mass% basic copper carbonate particles and 98 mass% cellulose fibers.

[evaluation]
(Fumigation test)
First, a 100 L acrylic chamber was prepared in a laboratory set at about 25°C. Next, the phosphine detector obtained as described above was placed in the 100 L acrylic chamber. Next, while checking the concentration with a gas detector tube, phosphine standard gas was continuously injected into the acrylic chamber so that the phosphine concentration in the acrylic chamber became 100 ppm. Then, photographs of the phosphine detector were taken at predetermined time intervals. The results are shown in Figure 5. Also, the results of comparing the phosphine detectors according to Examples 2 to 6 before and after 24 hours of exposure are shown in Figure 6.

As shown in Figures 5 and 6, the higher the concentration of basic copper carbonate particles, the better the visibility of the black discoloration. When the content of basic copper carbonate particles in the phosphine detection unit was 10 mass% or more, the visibility of the black discoloration was particularly excellent.

Next, to evaluate the presence or absence of a binder in the phosphine detection section, the following phosphine detection elements were prepared in the following examples and comparative examples.

[Example 7]
A phosphine detector was prepared in the same manner as in Example 1.

[Comparative Example 7]
A phosphine detector was prepared in the same manner as in Example 1, except that the composition of the phosphine detector was 45.45% by mass of basic copper carbonate particles, 45.45% by mass of cellulose fibers, and 9.1% by mass of binder solids. Binder N (CELLENPIA (registered trademark) TEMPO oxidized CNF (1% standard product) manufactured by Nippon Paper Industries Co., Ltd.) was used as the binder.

[evaluation]
(Fumigation test)
The fumigation test was carried out in the same manner as above, and the phosphine detector was photographed at predetermined intervals. The results are shown in FIG.

As shown in Figure 7, the phosphine detector of Example 7, which does not contain a binder, had better visibility of the black discoloration than the phosphine detector of Comparative Example 7, which contains a binder.

These results confirm that it is possible to continuously detect phosphine without power consumption, and that it is possible to provide a highly responsive phosphine detector.

Although the present embodiment has been described above, the present embodiment is not limited to these, and various modifications are possible within the scope of the gist of the present embodiment.

1 Phosphine detector 10 Support 20 Phosphine detector 30 Packaging material

Claims (5)

A support;
a phosphine detection unit supported on the surface of the support and including a mixture of a plurality of basic copper carbonate particles and a plurality of cellulose fibers;
Equipped with
The average length of the plurality of cellulose fibers is 0.9 mm or more and 2 mm or less,
The average fiber diameter of the plurality of cellulose fibers is 15 μm or more and 50 μm or less,
A phosphine detector, wherein the phosphine detector portion is substantially free of a binder. The phosphine detector according to claim 1, wherein the support is a porous body having at least one of communicating pores and through pores. The phosphine detector according to claim 1 or 2, wherein the support is filter paper. Further comprising a breathable packaging material;
The phosphine detector according to claim 1 , wherein the phosphine detector supported on the support is wrapped in the packaging material. The phosphine detection element according to claim 1 or 2, wherein a content of the plurality of cellulose fibers is 40% by mass or more and 93% by mass or less with respect to the phosphine detection section.

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