Structure for freshness label with sealing member and freshness label with sealing member

Abstract

To provide a freshness label with an encapsulation component that can confirm freshness of a food product simply and with high accuracy and a structure for a freshness label with an encapsulation component to realize the freshness label with the encapsulation component.SOLUTION: According to an embodiment, a structure for a freshness label with an encapsulation component is provided. A structure for a freshness label that the structure for the freshness label with the encapsulation component comprises includes a substrate and a fluorescent material layer including an aggregation induction fluorescent material fastened on the substrate. An encapsulation component that the structure for the freshness label with the encapsulation component comprises is an aqueous liquid impermeability encapsulation component that encapsulates the structure for the freshness label and includes a part consisting of parts made of an aqueous liquid impermeability and gas permeability porous member.SELECTED DRAWING: Figure 4

Description

[Technical field]

[0001] The present invention relates to a structure for a freshness label with a sealing member and a freshness label with a sealing member. [Background technology]

[0002] Fresh foods such as marine products, fruits and vegetables, and livestock products have poor storage properties at room temperature and are prone to spoilage, so there is a need for a method to evaluate their freshness. Various methods have been tried to evaluate the freshness of fresh foods, such as sensory evaluation, chemical evaluation, physical evaluation, and microbial methods. Sensory evaluation is a method of evaluating fresh foods based on their appearance, odor, firmness, and other tactile sensations. Chemical evaluation is based on gas chromatography-mass spectrometry of chemical components generated by deterioration and decay of fresh foods, and liquid chromatography-mass spectrometry of nucleic acid-related compounds. Physical evaluation is a method of evaluating fresh foods based on physical indicators such as the stiffness index (RI value), breaking strength, texture, and impedance. Microbiological methods are a method of examining the number of general viable bacteria, putrefactive bacteria, and pathogenic bacteria contained in fresh foods.

[0003] The sensory evaluation method does not require expensive measuring equipment and can evaluate freshness in a short time, but there is a problem that the results vary depending on the evaluator. The chemical evaluation method, physical evaluation method, and microbiological technique are less likely to produce results that vary depending on the evaluator, but they are not easy to perform because they require equipment and facilities, and may take time to measure. In other words, these methods sacrifice simplicity or accuracy.

[0004] To cope with such problems, a freshness label using an aggregation-induced fluorescent substance has been proposed. With this freshness label, the freshness of food can be evaluated by measuring the fluorescence intensity of the label. Here, the aggregation-induced fluorescent substance is a compound that exhibits aggregation-induced emission (AIE). The aggregation-induced fluorescent substance exhibits weak fluorescence or no fluorescence when each molecule is dissolved in a solution such as an organic solvent in which it can be dissolved. When the molecules of the aggregation-induced fluorescent substance in a dissolved state react with, for example, a chemical component released due to spoilage or deterioration of fresh food, they aggregate to form an aggregate, and this aggregate emits strong fluorescence. It is preferable that the aggregation-induced fluorescent substance is designed to have a functional group that reacts with spoilage components. For example, when an amine component, which is one of the spoilage components, is reacted with the aggregation-induced fluorescent substance, it is preferable that the aggregation-induced fluorescent substance has a carboxylic acid group. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2017-058233 A [Patent Document 2] Patent No. 6295351 [Patent Document 3] JP 2015-184332 A [Patent Document 4] JP 2017-102066 A Summary of the Invention [Problem to be solved by the invention]

[0006] The problem that the present invention aims to solve is to provide a freshness label with a sealing member that can easily and accurately check the freshness of food, and a structure for a freshness label with a sealing member for realizing this freshness label with a sealing member. [Means for solving the problem]

[0007] According to an embodiment, a freshness label structure with a sealing member is provided. The freshness label structure includes a substrate and a phosphor layer including an aggregation-induced phosphor fixed to the substrate. The sealing member of the freshness label structure is an aqueous liquid-impermeable sealing member that seals the freshness label structure, and includes a portion made of an aqueous liquid-impermeable and gas-permeable porous material.

[0008] According to another embodiment, a freshness label with a sealing member is provided. The freshness label with a sealing member includes a freshness label structure with a sealing member according to an embodiment, and water carried in the freshness label structure. [Brief description of the drawings]

[0009] [Figure 1] FIG. 2 is a perspective view showing a structure for freshness labels provided in a structure for freshness labels with a sealing member according to an embodiment. [Diagram 2] FIG. 2 is an enlarged cross-sectional view of the freshness label structure shown in FIG. 1. [Diagram 3] FIG. 2 is a top view illustrating an example of a freshness label with a sealing member according to an embodiment. [Figure 4] 4 is a cross-sectional view of the freshness label with the sealing member shown in FIG. 3. [Diagram 5] FIG. 13 is a cross-sectional view illustrating another example of a freshness label with a sealing member according to an embodiment. [Figure 6] FIG. 13 is a cross-sectional view illustrating another example of a freshness label with a sealing member according to an embodiment. [Figure 7] FIG. 2 is a diagram for explaining the quenching mechanism of an aggregation-induced fluorescent substance. [Figure 8] FIG. 1 is a perspective view showing an example of a packaged food product including a freshness label according to an embodiment. [Figure 9] FIG. 1 is a diagram showing the decomposition process of nucleic acid-related substances. [Figure 10] FIG. 1 is a diagram showing a method for calculating the K value. [Figure 11] FIG. 13 is a top view illustrating another example of a freshness label with a sealing member according to an embodiment. [Figure 12]FIG. 11 is a summary of images obtained in an example using horse mackerel. [Figure 13] FIG. 11 is a summary of images obtained in examples with and without a moisturizer. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] As a result of intensive research by the present inventors, it was found that there is room for improvement in the accuracy of the freshness label containing the aggregation-induced phosphor. That is, a freshness label containing an aggregation-induced phosphor dissolved in an organic solvent is placed, for example, in a container in which the fresh food is sealed and in the vicinity of the fresh food. Fresh food is a food with a high water content. Therefore, it is considered that the water vapor pressure in the container in which the fresh food and the freshness label are sealed will reach the saturated water vapor pressure over time. Since the aggregation-induced phosphor is a water-insoluble substance, it was thought that it would be less susceptible to the influence of water. However, the present inventors found that the fluorescence of the freshness label weakens when the water vapor pressure in the container increases. That is, since the fluorescence intensity of the freshness label is influenced by the water in the gas phase, in an environment in which humidity gradually increases, the influence of chemical components released due to the decay or deterioration of the fresh food is not accurately reflected in the fluorescence intensity.

[0011] In addition, when freshness labels are sealed in a container with fresh foods such as fresh fish or raw meat, the freshness labels are often directly covered with drips, which are aqueous liquid components released from the fresh foods. Furthermore, freshness labels are sometimes used to manage the freshness of landed fresh fish that are placed in a cooler box, and when the cooler box is transported, ice water that is placed therein as a cooling material splashes, causing the labels to be directly covered with water droplets. If water droplets fall on the freshness label, this directly affects the fluorescence of the freshness label. For freshness labels that evaluate the freshness of foods by measuring the fluorescence intensity of the freshness label, it is particularly important to provide a shielding property against aqueous liquids in order to accurately measure freshness. The present invention is based on these findings.

[0012] Hereinafter, the embodiments will be described in detail with reference to the drawings. Components having the same or similar functions are designated by the same reference numerals throughout the drawings, and duplicated descriptions will be omitted.

[0013] The freshness label structure with a sealing member according to the embodiment includes a freshness label structure and a sealing member that is impermeable to aqueous liquids and seals the structure. In the following, when simply referring to a "freshness label structure", it means a freshness label structure that does not include a sealing member, and is distinguished from a freshness label structure with a sealing member that includes a sealing member.

[0014] The freshness label structure includes a substrate and a phosphor layer. The phosphor layer includes an aggregation induced phosphor fixed to the substrate. The freshness label structure includes a solid aggregation induced phosphor, and therefore exhibits strong fluorescence.

[0015] FIG. 1 is a perspective view that shows a schematic diagram of a freshness label structure provided in a freshness label structure with a sealing member according to an embodiment. The freshness label structure 1 shown in FIG. 1 includes a substrate 2 and a phosphor layer (not shown). FIG. 2 is an enlarged cross-sectional view of the freshness label structure shown in FIG. 1. The freshness label structure 1 shown in FIG. 1 and FIG. 2 is an example in which filter paper is used as the substrate 2. A phosphor layer 3 is supported on the fibers 2a of the substrate 2. The phosphor layer 3 includes an aggregation-induced phosphor 3a fixed to the fibers 2a of the substrate 2.

[0016] The shape and material of the substrate 2 are not limited as long as the substrate 2 is capable of being impregnated with water. The substrate 2 is, for example, a porous body or a mesh structure. The substrate 2 may be circular as shown in FIG. 1, or may be polygonal. The thickness of the substrate 2 is, for example, 0.1 mm to 1.0 mm. This is not particularly limited as long as the amount of fluorescence emitted from the aggregation induced phosphor can be ensured, and conversely, the thickness may be such that it is not too thick as to hinder the reaction between the aggregation induced phosphor and decay components inside the substrate.

[0017] The substrate 2 includes, for example, synthetic fibers, inorganic fibers, natural fibers, or a mixture thereof. Examples of synthetic fibers include polyolefin-based fibers and cellulosic fibers. Examples of inorganic fibers include glass fibers, metal fibers, alumina fibers, and activated carbon fibers. Examples of natural fibers include wood pulp and hemp pulp. The substrate 2 is preferably a layer made of glass fibers.

[0018] The phosphor layer 3 contains an aggregation induced phosphor 3a, and preferably consists of only the aggregation induced phosphor 3a. The phosphor layer 3 is supported on the substrate 2. The phosphor layer 3 is preferably supported in the form of a thin layer on the surface of the fibers 2a or the like of the substrate 2.

[0019] The thickness of the phosphor layer 3 is preferably such that the fluorescence intensity becomes sufficiently small when the phosphor layer 3 is left in an environment at 25° C. and a relative humidity of 100%. Here, the fluorescence intensity becomes sufficiently small when the fluorescence intensity when the phosphor layer 3 is left in an environment at 25° C. and a relative humidity of 100% is calculated as a relative value of 30% or less, with the fluorescence intensity when the phosphor layer 3 is left in an environment at 10° C. and a relative humidity of 20% being taken as 100%. The fluorescence intensity is measured, for example, using a photodetector such as a photodiode, or using an imaging element such as a complementary metal-oxide-semiconductor (CMOS) image sensor and a charge-coupled device (CCD) image sensor. When a color imaging element is used, the fluorescence intensity is, for example, the calculated average of the gradation values ​​of RGB.

[0020] The thickness of the phosphor layer 3 can affect the fluorescence intensity of the freshness label. That is, if the phosphor layer 3 is made moderately thick, the fluorescence intensity of the freshness label tends to be stronger. On the other hand, if the phosphor layer 3 is made excessively thick, the change in the fluorescence intensity in response to the change in freshness becomes small. The thickness of the phosphor layer 3 is preferably 30 nm or less, and more preferably 20 nm or less. It is desirable to adjust the thickness of the phosphor layer 3 to a range where the change in freshness can be easily confirmed according to the amount of chemical components (hereinafter referred to as target components) released due to spoilage or deterioration of fresh food. The thickness of the phosphor layer 3 can be confirmed, for example, by a transmission electron microscope (TEM).

[0021] Here, the "target component" will be described. Fresh foods may release one or more target components into the gas phase when spoiled or deteriorated. The target components include, for example, acidic components such as aldehydes and carboxylic acids, basic components such as alcohols, ammonia, and amines, esters, and ketones. Aldehydes include, for example, hexanal, 3-methylbutanal, nonanal, isovaleraldehyde, or mixtures thereof. Carboxylic acids include, for example, formic acid, acetic acid, isovaleric acid, or mixtures thereof. Amines include, for example, trimethylamine, dimethylamine, 1,2-ethylenediamine, 1,3-propanediamine, 1,4-butanediamine, 1,5-pentanediamine, 1,6-hexanediamine, spermidine, spermine, histamine, tryptamine, or mixtures thereof. Alcohols include, for example, ethanol, isopropyl alcohol, 3-methyl-1-butanol, 1-pentanol, 1-butanol, or mixtures thereof. Esters include, for example, ethyl acetate, methyl acetate, ethyl propionate, or mixtures thereof. Ketones include, for example, methyl ethyl ketone, acetone, mercaptoacetone, or mixtures thereof.

[0022] The aggregation induced phosphor 3a may form the phosphor layer 3 as a granular layer as shown in Fig. 2, or may form the phosphor layer 3 as a continuous film without gaps. In the phosphor layer 3 as a granular layer, each particle contains a plurality of molecules of the aggregation induced phosphor 3a, and the number of molecules of the aggregation induced phosphor 3a located on the shortest line connecting each position within the particle to the particle surface is, for example, 10 or less.

[0023] The aggregation-inducing phosphor 3a preferably contains a phosphor having a polar functional group. The aggregation-inducing phosphor 3a containing a polar functional group is easily reactive with the target component, and the accuracy of freshness evaluation using the freshness label can be improved. In addition, the aggregation-inducing phosphor 3a tends to have high solubility or dispersibility in water. The polar functional group may be an acidic functional group or a basic functional group. Examples of the acidic functional group include a carboxyl group and a sulfo group. Examples of the basic functional group include a hydroxyl group and an amino group. The aggregation-inducing phosphor 3a may contain a plurality of types of acidic functional groups or basic functional groups. The aggregation-inducing phosphor 3a preferably contains two or more carboxyl groups in one molecule.

[0024] As the aggregation-induced phosphor 3a, a compound having a tetraphenylethylene skeleton shown in structural formula (2), a silole skeleton shown in structural formula (3), or a phosphole oxide skeleton shown in structural formula (4) can be used. Each of these compounds may be in a cis form, a trans form, or a mixture of a cis form and a trans form.

[0025] [ka]

[0026] [ka]

[0027] [ka]

[0028] From the viewpoint of particularly excellent reactivity with the target component, aggregation-induced phosphor 3a preferably contains a tetraphenylethylene derivative represented by the following general formula (I).

[0029] [ka]

[0030] In the general formula (I), R1, R2, R3, and R4 are each independently -L1M1, -(CH2) m -L2M2, -X-(CH2) n -L3M3, -Y-(CH2) o -Z-(CH2) p -L4M4 (wherein L1, L2, L3 and L4 independently represent -CO2- or -SO3-; M1, M2, M3 and M4 independently represent a hydrogen atom or a cation; X, Y and Z independently represent -O-, -NH- or -S-; and m, n, o and p independently represent an integer of 1 to 6), a hydrogen atom, a halogen atom, a hydroxyl group, a nitro group, a carbamoyl group, an alkyl group having 1 to 6 carbon atoms, selected from the group consisting of a haloalkyl group having 1 to 6 carbon atoms, an alkenyl group having 2 to 6 carbon atoms, a cycloalkyl group having 3 to 10 carbon atoms, an alkyloxy group having 1 to 6 carbon atoms, an acyl group having 2 to 6 carbon atoms, an amino group, an alkylamino group having 1 to 6 carbon atoms, an aryl group having 6 to 10 carbon atoms, and a heteroaryl group having 5 to 10 carbon atoms, and at least two of R1, R2, R3, and R4 are each independently selected from the group consisting of -L1M1, -(CH2) m -L2M2, -X-(CH2) n -L3M3 and -Y-(CH2) o -Z-(CH2) p -L4M4 (wherein L1, L2, L3, L4, M1, M2, M3, M4, X, Y, Z, m, n, o, and p are as defined above).

[0031] Specific examples of the tetraphenylethylene derivative include the compounds represented by the following structural formulas (5), (6), (7) and (8).

[0032] [ka]

[0033] [ka]

[0034] [ka]

[0035] [ka]

[0036] This freshness label structure 1 is produced, for example, by the following method. First, the aggregation induced phosphor 3a is dissolved in an organic solvent to prepare a treatment liquid. The type of organic solvent may be any that can dissolve the aggregation induced phosphor 3a, and is preferably one with a low evaporation temperature. For example, ethanol is used as the organic solvent. For example, when the compound represented by the structural formula (6) is used, the concentration of the aggregation induced phosphor 3a in the treatment liquid is set to 50 μM (molar mass) or more and 1 mM (molar mass) or less.

[0037] Next, the substrate 2 is immersed in the treatment liquid to impregnate the substrate 2 with the treatment liquid, and then the substrate 2 is pulled out of the treatment liquid and dried. Instead of immersing the substrate 2 in the treatment liquid, the substrate 2 may be impregnated with the treatment liquid by dropping the treatment liquid using a dropper or the like. In this manner, the structure 1 for freshness label is obtained. The structure 1 for freshness label typically does not contain an organic solvent.

[0038] The freshness label structure 1 may further contain a moisturizer. When the freshness label structure 1 contains a moisturizer, evaporation of water can be suppressed in a freshness label in which water is supported by the freshness structure 1. A freshness label with a sealing member using the freshness label structure 1 containing a moisturizer in this way has excellent water retention properties for the water contained in the freshness label, and can maintain the initial fluorescent state until it is used to evaluate the freshness of food.

[0039] Examples of the moisturizer include glycerin, propylene glycol, triacetin, and sorbitol. The structure for freshness label containing the moisturizer can be obtained by adding a predetermined amount of the moisturizer to the above-mentioned method for producing the structure for freshness label 1 in the preparation of the above-mentioned treatment liquid in which the aggregation-induced phosphor 3a is dissolved in an organic solvent. For example, when glycerin is used as the moisturizer, the concentration of the moisturizer in the treatment liquid may be 1% by mass or more and 10% by mass or less.

[0040] The freshness label includes a structure 1 for freshness labels shown in FIG. 1 and water held by the structure 1 for freshness labels. The freshness label with a sealing member is a structure in which the structure for freshness labels with a sealing member carries water. In the following, when simply referring to a "freshness label", it means a freshness label that does not include a sealing member, and is distinguished from a freshness label with a sealing member that includes a sealing member. In addition, the freshness label with a sealing member and the freshness label structure with a sealing member share the sealing member in common. The freshness label with a sealing member will be described below, but the description can be substituted for the description of the structure for freshness labels with a sealing member by replacing "freshness label" with "structure for freshness labels".

[0041] The sealing member of the freshness label with sealing member according to the embodiment is impermeable to aqueous liquids and includes a portion made of a porous material that is impermeable to aqueous liquids and permeable to gas. The sealing member has a function of preventing aqueous liquids from directly contacting the phosphor layer by sealing the freshness label from the external atmosphere surrounding the freshness label (hereinafter referred to as the "ambient atmosphere") (hereinafter also referred to as the "waterproof function"). In addition, the porous material included in at least a part of the sealing member has a function of allowing chemical components (target components) released due to spoilage or deterioration of food such as fresh food to come into contact with the phosphor layer through the porous material, by being gas permeable, in addition to the waterproof function. Here, the term "aqueous liquid" refers to liquid water or an aqueous solution containing water, and examples thereof include water, ice water, seawater, and drips from fresh food.

[0042] The sealing structure of the freshness label using the sealing member is not particularly limited as long as it seals the freshness label from the surrounding atmosphere, and the portion of the sealing member made of a porous material that is impermeable to aqueous liquids and permeable to gas is in contact with the surrounding atmosphere, and the target component can come into contact with the freshness label through the porous material.

[0043] Hereinafter, a freshness label with a sealing member according to an embodiment will be described with reference to the drawings. FIG. 3 is a top view showing an example of a freshness label with a sealing member according to an embodiment, and FIG. 4 is a cross-sectional view thereof. The freshness label with a sealing member 10 shown in FIG. 3 and FIG. 4 includes a freshness label 11 and a sealing member consisting of a holder 12, a porous member 13, and a joining member 14 in a form that seals the freshness label 11 from the surrounding atmosphere. The freshness label 11 includes a structure for freshness labels 1 shown in FIG. 1 and FIG. 2, and water (not shown) carried by the structure for freshness labels 1. The holder 12, the porous member 13, and the joining member 14 constituting the sealing member are impermeable to aqueous liquids, and among them, the porous member 13 is also gas permeable. Note that the joining member 14 shown in FIG. 4 is not shown in FIG. 3.

[0044] The holder 12, together with the porous member 13 and the joining member 14, constitutes a sealing member that seals the freshness label 11. The holder 12 supports the freshness label 11 in a form in which the porous member 13 can contact the freshness label 11. The material of the holder 12 may be impermeable to aqueous liquids. In addition, a material that does not emit fluorescence from the holder 12 itself is preferable, but even if it emits fluorescence, there is no particular limitation as long as it does not affect the fluorescence observation of the freshness label 11. Examples of materials for the holder 12 include glass, resins (e.g., acrylic resin, PET, PP, PE, cycloolefin polymer, etc.), and paper. In particular, since cycloolefin polymers hardly emit fluorescence themselves, they are suitable as materials for the holder 12 when the freshness label is observed fluorescently through the holder 12. In addition, when the freshness label is observed fluorescently through the porous member 13, if the glass or resin is blackened to make it opaque, it is less susceptible to the influence of the base material fluorescence, and the selection of materials can be expanded.

[0045] The porous member 13 covers the main surface of the freshness label 11 opposite to the main surface supported by the holder 12. The porous member 13 is in contact with the surrounding atmosphere, allowing the target component to come into contact with the freshness label 11 through the porous member 13. In another example, the entire sealing member may be made of the porous member 13, and the entire freshness label 11 may be sealed. There is no limitation on the shape of the porous member 13, and it is not limited to the layered shape shown in Figures 3 and 4. As long as it fulfills the functions of being impermeable to aqueous liquids and permeable to gases, it may have other shapes, such as a cylindrical shape, a bag shape, or a shape integrated with a food packaging material such as a wrap film.

[0046] The material of the porous member 13 is not particularly limited as long as it is a material that is impermeable to aqueous liquids and permeable to gas, and any material can be used. As such a material, a hydrophobic PTFE (polytetrafluoroethylene) membrane filter is particularly preferable as a material for the porous member 13 because it has low wettability to aqueous liquids, good liquid impermeability due to water repellency, and good gas permeability due to porosity. The pore size of the hydrophobic PTFE membrane filter is preferably, for example, 1 μm to 10 μm, and more preferably 3 μm to 5 μm. Since the PTFE membrane filter itself does not exhibit fluorescence, it does not hinder the fluorescent observation of the fluorescent layer, but a filter with a thickness that can transmit excitation light and fluorescence to a degree necessary for the purpose of judging the freshness label is selected. Furthermore, a cooking sheet with a paper surface treated with silicone or Teflon (registered trademark) can also be used as the porous member 13.

[0047] The joining member 14 joins the holder 12 and the porous member 13, thereby sealing the freshness label 11 in a form in which the freshness label 11 is sandwiched between the holder 12 and the porous member 13. The joining member 14 may be, for example, a known adhesive such as a thermocompression adhesive or an adhesive tape. Furthermore, the strength of the waterproof structure of the sealing member including the joining member 14 for the freshness label 11 may be set according to the period of use of the freshness label 10 with the sealing member, and after the purpose of the assessment by the freshness label 10 with the sealing member is achieved, the adhesive strength of the joining member 14 may be reduced.

[0048] Other examples of freshness labels with sealing members will be described below. Fig. 5 is a cross-sectional view showing another example of a freshness label with a sealing member according to an embodiment. The freshness label with a sealing member 20 shown in Fig. 5 includes a freshness label 11 and a sealing member made of a holder 12, a porous member 13, joining members 14, 14A and 14B, and a film 15 in a form that seals the freshness label 11 from the surrounding atmosphere.

[0049] The freshness label 20 with a sealing member is most different from the freshness label 10 with a sealing member shown in Figs. 3 and 4 in that the arrangement of the porous member 13 is different. In the freshness label 20 with a sealing member, the porous member 13 is arranged between the joining members 14a and 14b that join the holder 12 and the film 15, and is joined to the holder 12 and the film 15. The film 15 is arranged at the position where the porous member 13 was arranged in the freshness label 10 with a sealing member. The film 15 is selected from non-fluorescent, aqueous liquid-impermeable films having a material and thickness that can transmit excitation light and fluorescence to a degree necessary for the purpose of judging the freshness label. The film 15 is preferably a transparent film that is non-fluorescent and aqueous liquid-impermeable. Examples of the film 15 include cycloolefin polymers and the like.

[0050] Another example (not shown) of the freshness label with a sealing member according to the embodiment is a freshness label with a sealing member 20 shown in Fig. 5, in which the arrangement of the porous member 13 is changed. For example, a freshness label with a sealing member having a sealing structure in which an opening is provided in a part of the holder 12 or the film 15 through which the freshness label 11 comes into contact with the surrounding atmosphere, and the porous member 13 is arranged in this opening, can be mentioned.

[0051] Fig. 6 is a cross-sectional view showing another example of a freshness label with a sealing member according to an embodiment. The freshness label with a sealing member 30 shown in Fig. 6 includes a freshness label 11 and a sealing member made of a first housing member 16, a second housing member 17, and a porous member 13 in a form that seals the freshness label 11 from the surrounding atmosphere. The first housing member 16 and the second housing member 17 are impermeable to aqueous liquids.

[0052] The first housing member 16 is made up of a first bottom wall 161 and a first peripheral wall 162 rising along the peripheral edge of the first bottom wall 161, and is provided with a groove 163 at the upper end of the first peripheral wall 162. The second housing member 17 is made up of a second bottom wall 171 and a second peripheral wall 172 rising along the peripheral edge of the second bottom wall 171, and the second bottom wall 171 is provided with an opening 173 in the center surrounded by the peripheral edge.

[0053] The freshness label 30 with a sealing member is formed by fitting the second peripheral wall 171 of the second housing member 17 into the groove 163 of the first peripheral wall 162 of the first housing member 16 with the porous member 13 disposed between the first housing member 16 and the second housing member 17. The porous member 13 is in contact with the surrounding atmosphere at the opening 173 of the second housing member 171. The freshness label 11 is disposed in the internal space 18 formed by the first housing 16 and the porous member 13, so that the intrusion of aqueous liquid from the outside is suppressed, while the freshness label 11 can come into contact with the target component through the porous member 13 in contact with the surrounding atmosphere. The strength of the waterproof structure for the fluorescent layer 3 by the sealing member including the first housing member 16 and the second housing member 17 may be set according to the period of use of the freshness label 30 with a sealing member, and the strength of the housing may be reduced after the purpose of judging the freshness label 30 with a sealing member is achieved.

[0054] Next, a method for producing a freshness label with a sealing member will be described using the freshness label 10 with a sealing member shown in Figs. 3 and 4 as an example. First, a process for manufacturing the freshness label 11 included in the freshness label 10 with a sealing member will be described. The freshness label 11 is a freshness label structure 1 carrying water, and in its manufacturing, the freshness label structure 1 is immersed in water to impregnate it with water, and then pulled out of the water. The freshness label structure 1 may be impregnated with water by dropping water using a dropper or the like, or the freshness label structure 1 may be exposed to water vapor to impregnate it with water. The type of water that can be used may be distilled water, pure water, ion-exchanged water, or a mixture thereof.

[0055] The freshness label structure 1 (freshness label 11) containing water is pulled out of the water and placed on the holder 12. Next, the joining member 16 is placed on the holder 12 so as to surround the freshness label 11, and the porous member 13 is placed on top of it to form a waterproof structure using a sealing material. When the joining member 16 is a thermocompression film, the holder 12 and the porous member 13 can be suitably bonded together by applying an appropriate pressure on a heated hot plate.

[0056] The process of making the structure for freshness labels 1 carry water to produce the freshness label 11 may be carried out after sealing the structure for freshness labels 1 in a sealing member. In other words, a structure for freshness labels with a sealing member including the structure for freshness labels 1 may be produced, and then the structure for freshness labels 1 may carry water to obtain the freshness label 10 with a sealing member. As a method for making the structure for freshness labels 1 carry water after sealing the structure for freshness labels 1 in a sealing member, the structure for freshness labels with a sealing member may be exposed to water vapor, or the structure for freshness labels with a sealing member may be immersed in water as a liquid. In the latter case, the process can be carried out in a short time.

[0057] As described above, the freshness label 11 provided in the freshness label with a sealing member according to the embodiment includes the structure for freshness labels 1 and water supported on the substrate 2. The amount of water contained may be such that the fluorescence of the freshness label 11 becomes weak or non-fluorescent. In other words, the freshness label structure 1 becomes weak or non-fluorescent by containing water. The present inventors believe that the mechanism behind this is as follows.

[0058] Fig. 7 is a diagram for explaining an example of the quenching mechanism of the aggregation induced phosphor. As shown in Fig. 7, when the molecular aggregate of the aggregation induced phosphor 3a comes into contact with water, water molecules enter the gaps between the molecules of the aggregation induced phosphor 3a, and the distance between the molecules increases. Alternatively, when the molecular aggregate of the aggregation induced phosphor 3a comes into contact with water, the conformation of the molecules of the aggregation induced phosphor 3a changes. When the molecular arrangement of the aggregation induced phosphor 3a changes in this way, the fluorescence of the aggregation induced phosphor 3a weakens.

[0059] In the freshness label structure 1 shown in FIG. 2, since there is almost no water, the molecules of the aggregation induced phosphor 3a form a layered structure. The aggregation induced phosphor 3a, whose molecules are arranged in this manner, can emit fluorescence with a relatively high intensity. In contrast, the freshness label 11 is impregnated with water, and water molecules enter the gaps between the molecules of the aggregation induced phosphor 3a. Therefore, compared with the freshness label structure 1, the freshness label 11 emits fluorescence with a weak intensity or does not emit fluorescence at all.

[0060] In particular, aggregation induced phosphor 3a containing a polar functional group such as a carboxyl group has a high affinity with water. Therefore, it is considered that aggregation induced phosphor 3a containing a polar functional group is likely to have weak or no fluorescence when water is added. The ionization reaction of aggregation induced phosphor (TPE-COOH) having a carboxyl group is shown in the following formula (II). This reaction is an equilibrium reaction. TPE-COOH ⇔ TPE-COO - + H + (II)

[0061] The freshness label 11 is placed in the vicinity of a food such as a fresh food as a freshness label 10 with a sealing member, and is used in a sealed state together with the food. FIG. 8 shows an example of a method of using the freshness label 10 with a sealing member. FIG. 8 is a perspective view showing an example of a packaged food including the freshness label 10 with a sealing member according to the embodiment. The packaged food 40 shown in FIG. 8 includes the freshness label 10 with a sealing member, a food P1, a tray T for supporting them, and a wrap film (not shown). The freshness label 10 with a sealing member and the food P1 are sealed by the tray T and the wrap film (not shown) so as not to come into contact with the outside air. That is, the tray T and the wrap film form a sealed container, and the freshness label 10 with a sealing member and the food P1 are enclosed in the sealed container. The freshness label 10 with a sealing member may be placed on the tray T as shown in FIG. 8, or may be attached to the inner surface of the wrap film.

[0062] The type of food P1 is not limited, and the freshness label with a sealing member is preferably used for foods that contain moisture, such as marine products and livestock products. The freshness label with a sealing member 10 can accurately evaluate the freshness without being affected by drips from the food P1.

[0063] As described below, the freshness of the packaged food 40 can be quantified by irradiating the sealing member-attached freshness label 10 with excitation light such as ultraviolet light and measuring the intensity (brightness) of the fluorescence. Here, as an example, it is assumed that the target components generated in the food P1 as the freshness decreases are acidic components, and the aggregation-inducing phosphor 3a contains an acidic functional group as a polar functional group.

[0064] When food P1 is fresh, the concentration of the target component in the atmosphere in the sealed container is low. In this case, the target component has little effect on the molecular arrangement of aggregation-inducing phosphor 3a. Therefore, in this case, aggregation-inducing phosphor 3a does not emit fluorescence with high intensity even when irradiated with excitation light.

[0065] When the freshness of the food P1 decreases, the concentration of the target component in the atmosphere inside the sealed container increases. When the concentration of the target component in the atmosphere increases, a part of the target component dissolves in the water contained in the freshness label 11. Since this aqueous solution has the same polarity as the polar functional group of the aggregation induced phosphor 3a, when the concentration of the target component in this aqueous solution increases, the affinity or solubility of the aggregation induced phosphor 3a in the aqueous solution decreases. Therefore, when the concentration of the target component in the atmosphere increases, the molecular arrangement of the aggregation induced phosphor 3a approaches a state in which no water is present. Therefore, when the freshness of the food P1 decreases, it is considered that the intensity of the fluorescence emitted by the aggregation induced phosphor 3a when irradiated with excitation light increases.

[0066] For example, an ultraviolet (UV) lamp is used to irradiate the sealing member-attached freshness label 10 with excitation light. The wavelength of the ultraviolet light varies depending on the type of aggregation-inducing phosphor 3a, but in one example, it is 350 nm or more and 530 nm or less. For example, a photodetector or an image sensor is used to measure the fluorescence intensity, as described above. For example, first, a fluorescent image is captured using a digital camera or the like while irradiating the sealing member-attached freshness label 10 with a UV lamp. Then, each RGB gradation value of this fluorescent image is obtained using image processing software. The fluorescence intensity of the freshness label 10 can be quantified from these gradation values. For example, the arithmetic mean of these gradation values ​​can be regarded as the fluorescence intensity.

[0067] As described above, when aggregation-inducing phosphor 3a having an acidic functional group is used and the target component is an acidic component, the fluorescence of freshness label 11 becomes higher in response to an increase in the concentration of the target component. On the other hand, when aggregation-inducing phosphor 3a having a basic functional group is used and the target component is a basic component, the fluorescence of freshness label 11 becomes higher in response to an increase in the concentration of the target component.

[0068] As described above, by using the freshness label 10 with a sealing member, the freshness of the food P1 can be quantified by a simple method of irradiating it with excitation light such as ultraviolet light and measuring the intensity (brightness) of the fluorescence. Moreover, this freshness quantification can be performed with high accuracy. The reason for this will be explained below.

[0069] As described above, food P1 for which the freshness label 10 with a sealing member is desired, such as fresh food, generally has a high water content. Therefore, the water vapor pressure in the sealed container increases over time and eventually reaches the saturated water vapor pressure.

[0070] When a freshness label containing a solution of an aggregation-induced fluorescent substance dissolved in an organic solvent is used, the moisture content of the freshness label eventually becomes almost constant, but is low immediately after sealing in a sealed container and increases over time. This is because the fresh food sealed in a sealed container with the freshness label releases moisture into the gas phase, and the increase in water vapor pressure continues until it reaches the saturated water vapor pressure. When the moisture content of the freshness label increases, the arrangement of the molecules of the aggregation-induced fluorescent substance changes, as described above, and as a result, the fluorescence intensity of the freshness label changes. Therefore, in the case of a freshness label using an organic solvent, the magnitude of the effect of water on the fluorescence intensity changes during the period from sealing in a sealed container to the time when the water vapor pressure reaches the saturated water vapor. Therefore, when such a freshness label is used, the freshness cannot be accurately evaluated.

[0071] The freshness label provided in the freshness label with a sealing member according to the embodiment contains water. Foods such as fresh foods release moisture into the gas phase. Therefore, during the period from when the freshness label is sealed in the sealed container until the water vapor pressure reaches saturated water vapor, the difference between the amount of moisture evaporated from the freshness label and the amount of moisture supplied from the gas phase to the freshness label is small. After the water vapor pressure reaches saturated water vapor, the amount of moisture evaporated from the freshness label and the amount of moisture supplied from the gas phase to the freshness label become equal. Therefore, the amount of moisture in the freshness label is maintained constant immediately after sealing in the sealed container. Therefore, according to the freshness label provided in the freshness label with a sealing member according to the embodiment, there is almost no change in the fluorescence intensity caused by the change in the amount of moisture.

[0072] Furthermore, in the freshness label with a sealing member according to the embodiment, the freshness label is sealed from the surrounding atmosphere with a sealing member that is impermeable to aqueous liquids, and thus the aqueous liquid is prevented from seeping into the sealing member. Therefore, the freshness label is not covered with, for example, drips from fresh foods in a sealed container, or water, ice water, or seawater used to keep fresh fish, seafood, etc. at a low temperature when transporting them. Therefore, when this freshness label with a sealing member is used, the only substances that affect the fluorescence intensity are those that are generated by the decomposition or deterioration of the ingredients contained in the food and diffuse into the gas phase.

[0073] From the above, the freshness label with a sealing member according to the embodiment can realize a simple and highly accurate freshness evaluation. Therefore, by using the freshness label with a sealing member according to the embodiment, not only the presence of the target component can be detected, but also the concentration and K value of the target component can be grasped. That is, the fluorescence intensity of the freshness label with a sealing member according to the embodiment can show a positive correlation with the concentration and K value of the target component.

[0074] The K value is an index of food freshness, and a high K value indicates low freshness. The K value is calculated from the amount of decomposition products that nucleic acid-related substances produce over time.

[0075] FIG. 9 is an explanatory diagram showing the decomposition process of nucleic acid-related substances. As shown in FIG. 9, adenosine triphosphate (ATP) contained in food is decomposed into adenosine diphosphate (ADP). ADP is decomposed into adenosine monophosphate (AMP). AMP is decomposed into inosine monophosphate (IMP). IMP is decomposed into inosine (HxR). HxR is decomposed into hypoxanthine (Hx). ATP, ADP, AMP, and IMP are substances contained in fresh foods, and HxR and Hx are substances contained in less fresh foods.

[0076] FIG. 10 is a diagram showing a method for calculating the K value. As shown in FIG. 10, the K value is a percentage of the total amount of HxR and Hx in the total amount of ATP, ADP, AMP, IMP, HxR, and Hx. The amounts of ATP, ADP, AMP, IMP, HxR, and Hx in food are calculated, for example, by high performance liquid chromatography or electrophoresis. In general, if the K value is 60% or more, the food is judged to be spoiled. Evaluation by the K value can indicate the freshness of the food relatively accurately. However, in order to calculate the K value, it is necessary to take a sample from the food and to use expensive analytical equipment.

[0077] As described above, the fluorescence intensity of the freshness label with a sealing member according to the embodiment is positively correlated with the concentration of the target component. The concentration of the target component is positively correlated with the K value. Therefore, if the fluorescence intensity of the freshness label is quantified and a calibration curve is prepared in advance that shows the relationship between this numerical value and the concentration or K value of the target component, the fluorescence intensity can be measured and the measurement results can be referenced to the calibration curve to obtain the concentration of the target component in the gas phase or the K value of the food.

[0078] Next, another method of using the freshness label according to the embodiment will be described. FIG. 11 is a top view that shows a schematic diagram of another example of the freshness label with a sealing member according to the embodiment. The freshness label with a sealing member 10A shown in FIG. 11 has the same structure as the freshness label with a sealing member 10 shown in FIG. 3, except that the freshness label 11A further contains an acid (not shown). That is, the freshness label with a sealing member 10A shown in FIG. 11 includes the freshness label 11A and a sealing member made of a holder 12, a porous member 13, and a joining member (not shown) in a form that seals the freshness label 11A from the surrounding atmosphere. The freshness label 11A includes the structure for freshness labels 1 shown in FIG. 1 and FIG. 2, and water and an acid carried by the structure for freshness labels 1. In other words, the freshness label 11A carries an acidic aqueous solution. For example, formic acid, hydrochloric acid, acetic acid, or a mixture thereof is used as the acid. From the viewpoint of safety, it is preferable to use acetic acid as the acid. In addition, it is preferable that the polar functional group of the aggregation-induced phosphor 3a is an acidic functional group. Here, as an example, the polar functional group of aggregation-inducing phosphor 3a is an acidic functional group.

[0079] The freshness label 10A with a sealing member shown in Fig. 11 can be obtained by, for example, immersing the freshness label 10 with a sealing member shown in Fig. 3 in an aqueous solution containing a high concentration of acid for a predetermined period of time. The content of the acid in the freshness label 10A with a sealing member can be adjusted according to the desired fluorescence intensity.

[0080] In the freshness label 10A with a sealing member shown in Fig. 11, since the freshness label 11A contains an acid, it is considered that the molecular arrangement of the aggregation-inducing phosphor 3a is close to a state in which no water is contained, or the conformation of the aggregation-inducing phosphor 3a is changed due to the presence of an acid component. Therefore, this freshness label 10A with a sealing member shows stronger fluorescence than the freshness label 10 with a sealing member shown in Fig. 3.

[0081] The fluorescence intensity of this freshness label 10A with a sealing member decreases when it comes into contact with a basic target component, and becomes non-fluorescent when it comes into contact with a certain amount or more of the basic target component. That is, the fluorescence intensity of the freshness label 10A with a sealing member shown in FIG. 11 may show a negative correlation with the concentration and K value of the target component. Therefore, as with the freshness label 10 with a sealing member shown in FIG. 3, if the fluorescence intensity of the freshness label 10A with a sealing member is quantified and a calibration curve showing the relationship between this numerical value and the concentration or K value of the target component is prepared in advance, the fluorescence intensity can be measured and the measurement result can be referred to the calibration curve to obtain the concentration of the target component in the gas phase or the K value of the food.

[0082] The freshness label with a sealing member may be distributed in the form of a freshness label structure with a sealing member that does not contain water or the like, and may be soaked with water or the like at the site where it is enclosed in a sealed container together with the food P1. In this case, the freshness label structure with a sealing member may be distributed as a freshness label kit that contains the freshness label structure with a sealing member and one or more liquids to be contained therein, that is, water, acid, or a combination of water and acid. Alternatively, the freshness label structure with a sealing member may be distributed as a freshness label kit that is divided into a sealing member and a freshness label structure and further contains one or more liquids to be contained in the freshness label structure. When a combination of water and acid is included in a freshness label kit, the water and the acid may be stored in separate containers, or may be mixed and stored in a single container as an aqueous solution.

[0083] Alternatively, the freshness label 10 or 10A with a sealing member, which is obtained by soaking the structure for freshness labels with a sealing member with water or the like, may be distributed and enclosed in a sealed container together with the food P1.

[0084] The structure for freshness labels included in the structure for freshness labels with a sealing member according to the embodiment described above includes a phosphor layer fixed to a substrate. Therefore, a freshness label can be prepared by impregnating the structure for freshness labels with water. A freshness label containing water is less susceptible to the influence of water in the gas phase, and therefore can evaluate the freshness of food with high accuracy compared to a freshness label containing an organic solvent. In addition, the freshness label with a sealing member according to the embodiment has a waterproof structure, and aqueous liquids present in the surrounding environment do not affect the fluorescence intensity, so that the freshness of food can be evaluated with high accuracy in various environments where aqueous liquids are present. EXAMPLES

[0085] <Example 1> In this example, a freshness label 10 with a sealant and a freshness label 10A with a sealant were manufactured, and the freshness of a fresh fish was evaluated using the freshness label 10A with a sealant as an initial freshness label state (initial state) for evaluating the freshness of food.

[0086] The freshness label 10 with a sealing member shown in Fig. 3 and Fig. 4 was manufactured by the following method. First, the aggregation-induced phosphor 3a was dissolved in ethanol to prepare a treatment liquid with a concentration of 200 μM. After the substrate 2 was immersed in this treatment liquid, the substrate 2 was pulled out of the treatment liquid, placed on the support 12, and dried. As the aggregation-induced phosphor 3a, the compound shown in the above structural formula (6) was used. As the substrate 2, a commercially available glass filter paper (GS-25; Advantech Co., Ltd.) was used. As the support 12, a glass plate was used. In this manner, the freshness label structure 1 shown in Fig. 1 was obtained.

[0087] Next, the bonding members 14 were arranged so as to surround the dried freshness label structure 1, and the hydrophobic porous member 13 was laminated thereon. A thermocompression film (Fixelon (registered trademark); Aicello Co., Ltd.) was used as the bonding member 14, and a PTFE filter (Mitex (registered trademark) membrane filter; pore size 5.0 μm; Merck Millipore Co., Ltd.) was used as the hydrophobic porous member 13. The obtained laminate was placed on a hot plate heated to 200 ° C., and a weight was placed on it and pressure was applied for 2 minutes, thereby bonding the porous member 13 and the holder 12 together, thereby obtaining a freshness label structure with a sealing member. When the freshness label structure with a sealing member was observed while irradiating ultraviolet light with a UV lamp, it was confirmed that it emitted strong fluorescence. The wavelength of the ultraviolet light irradiated by the UV lamp was 365 nm.

[0088] Next, this freshness label structure with a sealing member was immersed in pure water. After leaving it in this state for half a day, it was pulled out of the pure water. At this time, the freshness label structure 1 absorbs moisture through the hydrophobic porous member 13 to become a freshness label 11, and thus a freshness label 10 with a sealing member shown in Figs. 3 and 4 was obtained. Hereinafter, this freshness label 10 with a sealing member is referred to as a freshness label R1 with a sealing member. When the freshness label R1 with a sealing member was observed while irradiating it with ultraviolet light from a UV lamp, it was confirmed that it was in a non-fluorescent quenching state. In addition, the freshness label R1 with a sealing member at this time was photographed using a digital camera, and digital image data was recorded. The image is shown in Fig. 12.

[0089] The obtained freshness label R1 with a sealing member was immersed in an aqueous solution of acetic acid with a concentration of several vol% for about an hour, and then pulled out. At this time, the freshness label 11 absorbed moisture and acetic acid through the hydrophobic porous member 13, and thus a freshness label 10A with a sealing member was obtained as shown in FIG. 11. Hereinafter, this freshness label 10A with a sealing member is referred to as a freshness label R2 with a sealing member. When the freshness label R2 with a sealing member was observed while irradiating it with ultraviolet light from a UV lamp, it was confirmed that it emitted strong fluorescence. In addition, the freshness label R2 with a sealing member at this time was photographed using a digital camera, and digital image data was recorded. The image is shown in FIG. 12.

[0090] The freshness label R2 with the sealing member obtained above was used as the initial freshness label state (initial state) for evaluating the freshness of food, and the freshness of fresh fish was evaluated by the method described below. Two freshness labels R2 with sealing members were placed and sealed in a plastic container containing pieces of fresh horse mackerel meat and a plastic container containing pure water for comparison. These containers were placed in a thermostatic chamber set at 20°C. After 20 hours, the freshness labels R2 with sealing members were removed from each container and observed while irradiating them with ultraviolet light from a UV lamp to confirm the fluorescence intensity. The freshness labels R2 with sealing members at this time were photographed using a digital camera and recorded using digital image data. The images are shown in Figure 12.

[0091] As shown in the image in Figure 12, the fluorescence intensity of the sealant freshness label R2 placed in a container containing horse mackerel was significantly lower than the initial fluorescence intensity before the test. This shows that the fluorescence intensity is reduced by the freshness label reacting with the target components that are generated as the horse mackerel's freshness decreases. In contrast, the fluorescence intensity of the sealant freshness label R2 placed in a container containing pure water was almost the same as the initial fluorescence intensity. As such, no decrease in fluorescence was observed in pure water, and it can be seen that the freshness determination ability of the sealant freshness label R2 is maintained.

[0092] <Example 2> In this example, the waterproof function of the freshness label with the sealing member was evaluated. The freshness label with a sealing member R2 manufactured in Example 1 was used as the freshness label with a sealing member. The freshness label with a sealing member R2 was placed in a container filled with pure water to the extent that the freshness label with a sealing member R2 was submerged in the pure water and immersed in the pure water. After one hour in this state, the freshness label with a sealing member R2 was taken out of the pure water and observed while irradiating ultraviolet light with a UV lamp to confirm the fluorescence intensity. In addition, the freshness label with a sealing member R2 at this time was photographed using a digital camera and recorded using digital image data. As a result, the fluorescence intensity was almost the same as that of the initial state of the freshness label with a sealing member R2 before immersion. In this way, it was confirmed that the freshness label with a sealing member R2 was able to maintain its waterproof function against aqueous liquids and its fluorescence mechanism as a freshness label.

[0093] Furthermore, when the freshness label R2 with the sealing member was immersed in pure water for one week and then observed, no deterioration such as peeling was observed in the hydrophobic porous member 13. It was also confirmed that the waterproofing property of repelling water droplets had not decreased.

[0094] <Example 3> In this example, the effect of a freshness label with a sealing member containing a moisturizing agent was evaluated. The freshness label with a sealing member containing a moisturizing agent is preferably used for freshness management of fresh fish, for example, when fresh fish is packed in a box and delivered to a market or a customer through a transportation process by truck or the like from a fishing port. Ice, water, seawater, etc. are usually placed in the box together with the fresh fish as a cooling material, and water droplets and ice blocks are scattered due to vibration during transportation. For this reason, in order to use the freshness label to manage the freshness of fresh fish in a cooling box, it is necessary to provide a waterproof structure for the freshness label so that the fluorescent emission state is not affected even if a certain volume of water or ice blocks covers the freshness label. In addition, it is required that the initial fluorescent emission state can be maintained as long as the freshness of the fresh fish is well maintained after transportation. Therefore, in this example, the fluorescent state of a freshness label with a sealing member containing a moisturizer and a freshness label with a sealing member not containing a moisturizer was evaluated under actual conditions using an insulated box containing fresh fish and ice water.

[0095] In this example, the freshness label with a sealing member R2 produced in Example 1 was used as a freshness label with a sealing member that does not contain a moisturizing agent. Also, the freshness label with a sealing member that contains a moisturizing agent was produced as follows, using glycerin as a moisturizing agent. First, in the production method of the freshness label with a sealing member R2 in Example 1, glycerin was added to a treatment liquid containing the aggregation-inducing phosphor 3a and ethanol prepared to produce the freshness label structure 1. Glycerin was added so that the concentration in the treatment liquid was 5 mass %. Other than this, it was produced in the same manner as the production method of the freshness label with a sealing member R2. The obtained freshness label with a sealing part containing a moisturizing agent is referred to as a freshness label with a sealing member R3.

[0096] Two freshness labels R3 with sealing members were placed and sealed in a cooler box containing fresh fish and ice water immediately after landing at the fishing port, and in a control cooler box containing only ice water. Two freshness labels R2 with sealing members were placed and sealed in a cooler box containing fresh fish and ice water immediately after landing at the fishing port, and in a control cooler box containing only ice water. These four types of cooler boxes were transported by truck from the fishing port to the market over a period of about two hours, and then transported by truck again to the expected customer over a period of about two hours. After transportation, each cooler box was kept in a refrigerated state with the water ice not completely melted until about one day had passed after landing and transportation.

[0097] Before transportation (when the fish was landed at the fishing port), half a day after transportation, and about one day after transportation, the freshness labels with the sealing members were taken out of each cold storage box and observed while irradiating ultraviolet light with a UV lamp to confirm the fluorescence intensity. Each freshness label with a sealing member at this time was photographed using a digital camera and recorded using digital image data. The images are shown in FIG. 13. From FIG. 13, it can be seen that the freshness label R3 with a sealing member containing glycerin has almost the same fluorescence intensity as before transportation even about one day after transportation in both the fresh fish judgment and the control, and is in a state where freshness judgment is possible. On the other hand, the freshness label R2 with a sealing member not containing glycerin exhibits the phenomenon of fluorescence quenching in both the fresh fish judgment and the control. Since this phenomenon appears in the control of only ice water, it is inferred that the concentration of acid components begins to decrease from the freshness label in the freshness label R2 with a sealing member. In other words, because there is no moisturizing ingredient, when the vibration state such as transporting in a cool box continues for a long time, the moisture in the freshness label goes in and out vigorously, and at the same time, the moisture concentration in the freshness label increases with the inflow and outflow of acidic ingredients, and it is presumed that the freshness cannot be judged and quenching occurs. This is thought to be a phenomenon specific to cases such as transporting in a cool box. Furthermore, the freshness state of the fresh fish after about one day was judged to be below 10% in the K value judgment, and it maintained a good freshness state.

[0098] Although some embodiments of the present invention have been described, these embodiments are presented as examples and are not intended to limit the scope of the invention. These novel embodiments can be implemented in various other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. These embodiments and their modifications are included in the scope and spirit of the invention, and are included in the scope of the invention and its equivalents described in the claims. [Explanation of symbols]

[0099] 1. Structure for freshness label 2...Base material 3. Phosphor layer 3a Aggregation-induced phosphors 10, 20, 30... Freshness label with sealing material 11. Freshness label 12...Holding body 13...Porous material 14, 14a, 14b... Joint members 15. Film 16... First housing member 161...First bottom wall 162 First Perimeter Wall 163...Groove 17...Second housing member 171...First bottom wall 172 First Perimeter Wall 173...Aperture 18. Interior space 40...Packaged food P1...Food T-Tray [Note] The invention as described in the claims of the present application as originally filed is set forth below. [1] A freshness label structure including a substrate and a phosphor layer including an aggregation induced phosphor attached to the substrate; A sealing member that is impermeable to aqueous liquids and seals the freshness label structure, the sealing member including a portion made of a porous material that is impermeable to aqueous liquids and permeable to gas; A structure for a freshness label with a sealing member. [2] The structure for a freshness label with a sealing member described in Appendix [1], wherein the phosphor layer is quenched when it contains water. [3] The structure for a freshness label with a sealing member described in Appendix [1] or [2], wherein the phosphor layer becomes fluorescent when it contains water and acid. [4] The freshness label structure with a sealing member according to any one of appendices [1] to [3], wherein the freshness label structure contains a moisturizing agent. [5] A freshness label structure with a sealing member according to any one of appendices [1] to [4], Water held in the freshness label structure; A freshness label with a sealing member comprising:

Claims

1. A freshness label structure including a substrate and a phosphor layer including an aggregation induced phosphor fixed to the substrate, the freshness label structure not including an organic solvent; A sealing member that is impermeable to aqueous liquids and seals the freshness label structure, the sealing member including a portion made of a porous material that is impermeable to aqueous liquids and permeable to gas; A structure for a freshness label with a sealing member.

2. The structure for a freshness label with a sealing member according to claim 1 , wherein the phosphor layer is quenched when it contains water.

3. The structure for a freshness label with a sealing member according to claim 1 or 2, wherein the phosphor layer becomes fluorescent when it contains water and an acid.

4. A structure for a freshness label comprising a substrate and a phosphor layer including an aggregation-induced phosphor fixed to the substrate; and A sealing member that is impermeable to aqueous liquids and seals the structure for freshness labels, the sealing member including a portion made of a porous material that is impermeable to aqueous liquids and permeable to gases. A freshness label structure with a sealing member, Water held in the freshness label structure; A freshness label with a sealing member comprising:

5. A freshness label with a sealing member as described in claim 4, wherein the freshness label structure contains a moisturizer.

Images