Heat-sensitive indicator and method for monitoring the temperature of an article

Abstract

To provide a thermo-sensitive indicator which is easy to deal with and is capable of temperature monitoring of an article simply.SOLUTION: A thermo-sensitive indicator 1 irreversibly displays that temperature has reached prescribed value or higher and includes: an inner container 2 which is breakable and seals an ink 6 inside; and an outer container 3 which has light transmissivity and flexibility and seals the inner container inside. A gap 7 between the inner container 2 and the outer container 3 is provided with a liquid absorption material 5. The ink 6 is adjusted to have a desired melting-point in accordance with the prescribed value, can break the inner container 2 by bending the outer container 3 non-destructively. After the inner container 2 is broken, the ink 6 is absorbed by the liquid absorption material 5 when the ink 6 becomes liquid, and coloring of the liquid absorption material 5 is visible from outside the outer container 3.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a heat-sensitive indicator that irreversibly indicates when a temperature reaches or exceeds a predetermined value, and a method for monitoring the temperature of an article using the heat-sensitive indicator.The heat-sensitive indicator of the present invention is easy to handle and allows for easier temperature monitoring of an article. [Background technology]

[0002] Strict temperature control is required during the transportation and storage of pharmaceuticals and other products. For example, it is necessary to ensure that the specified temperature is maintained during transportation and storage, and to promptly detect any deviations. Temperature ranges and conditions for transportation include room temperature (15°C to 25°C), refrigerated (2°C to 8°C), and frozen (-25°C to -15°C). Long-term storage of biological samples often requires frozen storage at temperatures below 0°C. Recently, nucleic acid medicines that use mRNA as an active ingredient, such as mRNA vaccines, have also begun to require transportation and storage at ultra-low temperatures below -70°C.

[0003] A heat-sensitive indicator is known for monitoring whether an environment in which a temperature-controlled item is placed is maintained within a predetermined temperature range. The heat-sensitive indicator described in Patent Document 1 includes ink whose melting point is adjusted to a desired temperature. When the heat-sensitive indicator is exposed to an environment above a predetermined temperature after use, the ink melts and irreversibly colors the ink. A user can determine whether the predetermined temperature has been maintained by using the presence or absence of coloring by the ink as an indicator. The heat-sensitive indicator described in Patent Document 2 also includes a similar heat-fusible ink, and can determine whether the predetermined temperature has been maintained by using the irreversible coloring by the ink as an indicator. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2016-57273 [Patent Document 2] Patent No. 5259027 Summary of the Invention [Problem to be solved by the invention]

[0005] The number of situations requiring temperature control of the environment in which an item is placed is steadily increasing, and there is a demand for appropriate and flexible measures depending on the type of item, the location where the item is placed, the temperature range to be controlled, etc. Therefore, an object of the present invention is to provide a heat-sensitive indicator that is easy to handle and enables simpler monitoring of the temperature of an item, and a method for monitoring the temperature of an item. [Means for solving the problem]

[0006] One aspect of the present invention is a heat-sensitive indicator that irreversibly displays when a temperature reaches a predetermined value or higher, comprising an inner container that is breakable and has ink sealed inside, and an outer container that is translucent and flexible and has the inner container sealed inside, a liquid-absorbing material is provided in the gap between the inner container and the outer container, and the ink is adjusted to have a desired melting point according to the predetermined value, the inner container can be broken by non-destructively bending the outer container, and after the inner container is broken, if the ink becomes liquid, the ink is absorbed into the liquid-absorbing material, and the color of the liquid-absorbing material can be seen from outside the outer container.

[0007] The heat-sensitive indicator of this embodiment includes a breakable inner container filled with ink, a translucent and flexible outer container filled with the inner container, and a liquid absorbent material disposed in the gap between the two containers. The ink filled in the inner container is adjusted to have a desired melting point. The indicator is configured to be breakable by non-destructively bending the outer container. According to this embodiment, simply bending the flexible outer container to break the inner container allows the liquid ink to be absorbed by the liquid absorbent material, allowing for easy temperature monitoring of an item. Furthermore, the color of the liquid absorbent material can be visually observed from outside the outer container, making it easy to determine the monitoring results.

[0008] Preferably, the liquid absorbent holds a solvent that is miscible with the ink in liquid form.

[0009] With this configuration, when the liquid ink is absorbed into the liquid absorbent material, the ink spreads more evenly, making it easier to visually check whether or not the ink is colored.

[0010] Another aspect of the present invention is a heat-sensitive indicator that irreversibly displays when a temperature reaches a predetermined value or higher, comprising an inner container that is breakable and has ink sealed inside, and an outer container that is translucent and flexible and has the inner container sealed inside, a liquid absorbent material is provided in the gap between the inner container and the outer container, and the liquid absorbent material holds a heat-fusible substance that has a desired melting point corresponding to the predetermined value and that, in a liquid state, can serve as a solvent for the colorant contained in the ink, the inner container can be broken by bending the outer container non-destructively, and after the inner container is broken, when the heat-fusible substance becomes liquid, the ink is absorbed into the liquid absorbent material, and the color of the liquid absorbent material can be seen from outside the outer container.

[0011] The heat-sensitive indicator of this embodiment also includes a breakable inner container filled with ink, a translucent and flexible outer container containing the inner container, and a liquid absorbent material provided in the gap between the two containers. In this embodiment, the liquid absorbent material contains a heat-fusible substance that has a desired melting point and, in its liquid state, can act as a solvent for the colorant contained in the ink. In this embodiment, simply by bending the flexible outer container and breaking the inner container, the ink can be absorbed into the liquid absorbent material containing the liquid heat-fusible substance, allowing temperature monitoring to begin with a simple operation. Furthermore, the color of the liquid absorbent material can be visually observed from outside the outer container, making it easy to determine the monitoring results.

[0012] Preferably, the inner container is concealed by the liquid absorbent material and is not visible from outside the outer container.

[0013] With this configuration, it is possible to more reliably determine whether or not the liquid absorbent material is colored.

[0014] Preferably, at least one of the outer surface of the inner container and the inner surface of the outer container is matte.

[0015] With this configuration, the matte surface becomes transparent when it comes into contact with liquid, making it easy to conceal the inside of the inner or outer container when not in use, thereby improving the ease of handling of the heat-sensitive indicator.

[0016] Preferably, the outer container is made of a silicone resin.

[0017] Preferably, the inner container and the outer container are both elongated in shape.

[0018] With this configuration, the operation of bending the outer container and breaking the inner container can be easily and reliably performed.

[0019] Preferably, the outer container has an elongated shape having a first end and a second end in the longitudinal direction, and an intermediate container that houses the inner container is further provided within the outer container, the intermediate container being open at the first end side and closed at the second end side, and the liquid absorbent material being provided in the gap between the intermediate container and the outer container.

[0020] In this aspect, the outer container has an elongated shape having a first end and a second end in the longitudinal direction, and an intermediate container is further provided within the outer container to cover the inner container. The intermediate container is open at the first end and closed at the second end. According to this aspect, after the inner container is broken, ink is released from the first end of the intermediate container, and absorption of the ink into the liquid absorbent material occurs from the first end. Therefore, the ink absorbed into the liquid absorbent material moves from the first end toward the second end. According to this aspect, more detailed information about temperature changes can be obtained from the progress of the ink, i.e., the degree of coloration.

[0021] Preferably, the outer container has an elongated shape having a first end and a second end in the length direction, and the inner container is disposed at a position offset toward the first end.

[0022] In this embodiment, the outer container has an elongated shape having a first end and a second end in the longitudinal direction, and the inner container is positioned biased toward the first end. Therefore, after the inner container is broken, the ink is absorbed into the liquid absorbent material from the first end, and the ink absorbed into the liquid absorbent material advances from the first end toward the second end. According to this embodiment, more detailed information on temperature change can be obtained from the progress of the ink, i.e., the degree of coloration.

[0023] Preferably, the outer container further comprises an outer skin covering part or all of the outer surface thereof, and the outer skin forms a visible portion that allows the outer container to be seen from the outside, and a concealed portion that prevents the outer container from being seen from the outside.

[0024] In this aspect, the outer container is provided with an outer skin that covers part or all of the outer surface of the outer container. The outer skin forms a visible portion that allows the outer container to be seen from the outside and a concealed portion that prevents the outer container from being seen from the outside. According to this aspect, the presence or absence and degree of coloring by ink can be observed through the visible portion, making it easy to observe the coloring.

[0025] Preferably, the visible portion is linear and extends from the first end toward the second end.

[0026] With this configuration, the degree of coloring by the ink can be easily observed.

[0027] The visible portion includes a plurality of visible portions, and the plurality of visible portions are arranged from the first end toward the second end.

[0028] With this configuration, the degree of coloring by the ink can be grasped in stages.

[0029] Preferably, a holding member is further provided for holding the heat sensitive indicator in a vertical position.

[0030] In an embodiment in which ink absorption into the liquid absorbent material begins at the first end after the inner container is broken, the heat-sensitive indicator can be positioned vertically with the first end facing down and the second end facing up during use, ensuring that ink is absorbed from the first end. In this embodiment, a holding member is provided to hold the heat-sensitive indicator in a vertical position. This configuration allows the heat-sensitive indicator to be held in a vertical position more easily and reliably during use.

[0031] Preferably, a reversible temperature indicator, the color of which changes reversibly depending on the temperature, is further provided on the outermost surface.

[0032] When using the above-mentioned thermosensitive indicator, it is preferable to cool the thermosensitive indicator to a predetermined temperature or lower in advance to solidify the ink or heat-fusible substance (pre-cooling). In this embodiment, a reversible temperature indicator whose color tone reversibly changes depending on the temperature is provided on the outermost surface of the thermosensitive indicator. According to this embodiment, it is easy to confirm that the thermosensitive indicator is in a pre-cooled state.

[0033] Preferably, the melting point is 0°C or lower.

[0034] This configuration allows for temperature monitoring of items that need to be transported or stored under refrigerated conditions.

[0035] Preferably, the melting point is −70° C. or lower.

[0036] This configuration makes it possible to monitor the temperature of items that need to be transported or stored at ultra-low temperatures.

[0037] Another aspect of the present invention is a method for monitoring the temperature of an object by monitoring the temperature of the environment in which the object is placed, comprising the steps of providing the above-mentioned heat-sensitive indicator, breaking the inner container, placing the heat-sensitive indicator in the environment together with the object to be temperature monitored, and checking the coloration state of the liquid absorbent material in the heat-sensitive indicator after a predetermined time has elapsed.

[0038] This aspect relates to a temperature monitoring method for an item, which uses the above-described heat-sensitive indicator to monitor the temperature of the environment in which the item is placed. According to this aspect, the temperature of the environment in which the item is placed can be easily monitored. For example, it is possible to monitor whether the temperature of the environment in which the item is placed has reached a predetermined value or higher, and if so, to what extent or how much the temperature has reached the predetermined value or higher. The "coloring state" includes not only the presence or absence of coloring, but also the degree or intensity of coloring.

[0039] Preferably, the method further comprises the step of cooling the heat sensitive indicator to a temperature equal to or lower than the predetermined value before fracturing the inner container.

[0040] With this configuration, the results of the temperature monitoring can be more easily determined.

[0041] In an embodiment using a heat-sensitive indicator in which the outer container has an elongated shape having a first end and a second end in the longitudinal direction, when checking the coloration state of the liquid absorbent material, the temperature monitoring results can be evaluated based on the degree of coloration from the first end to the second end.

[0042] Preferably, the predetermined value is selected from temperatures below 0°C.

[0043] This configuration allows for temperature monitoring of items that need to be transported or stored under refrigerated conditions.

[0044] Preferably, the predetermined value is selected from temperatures below -70°C.

[0045] This configuration makes it possible to monitor the temperature of items that need to be transported or stored at ultra-low temperatures. [Effects of the Invention]

[0046] According to the present invention, the temperature of an item can be monitored more easily. [Brief explanation of the drawings]

[0047] [Figure 1] 1A and 1B are cross-sectional views showing the structure of a heat-sensitive indicator according to a first embodiment of the present invention, in which (a) shows only the inner container and the outer container, and (b) shows the state in which a liquid absorbent material and ink are provided. [Figure 2] 10A and 10B are cross-sectional views showing the structure of a thermal indicator according to a second embodiment of the present invention, where (a) shows only the inner container, outer container, and intermediate container, and (b) shows the state equipped with a liquid absorbent material and ink. [Figure 3]10A and 10B are cross-sectional views showing the structure of a heat-sensitive indicator according to a third embodiment of the present invention, where (a) shows only the inner container and the outer container, and (b) shows the state in which the indicator is equipped with a liquid absorbent material and ink. [Figure 4] 10(a) and 10(b) are cross-sectional views showing the structure of a heat-sensitive indicator according to a fourth embodiment of the present invention. [Figure 5] FIG. 2 is an explanatory diagram showing an example of a visible portion. [Figure 6] 10(a) to 10(c) are explanatory diagrams showing examples in which a plurality of visible portions are provided. [Figure 7] FIG. 10 is an explanatory diagram showing another example in which a plurality of visible portions are provided. [Figure 8] 10(a) to 10(g) are explanatory views showing examples of holding members. DETAILED DESCRIPTION OF THE INVENTION

[0048] Hereinafter, embodiments of the present invention will be described with reference to the drawings. In order to facilitate understanding of the invention, the size and thickness of each component in each drawing are exaggerated and may not necessarily correspond to the actual size, ratio, etc.

[0049] 1(a) and 1(b), a heat-sensitive indicator 1 according to a first embodiment irreversibly indicates that a temperature has reached a predetermined value or higher. The heat-sensitive indicator 1 comprises an inner container 2, an outer container 3, a liquid absorbent material 5, and ink 6.

[0050] The inner container 2 is a thin, elongated, approximately cylindrical sealed container. The inner container 2 is frangible and easily breaks when bent. The inner container 2 is an ampoule made of, for example, glass, ceramics, or a resin with low cold resistance that can be fractured at a set temperature. The ink 6, which will be described later, is sealed inside the inner container 2.

[0051] The outer container 3 is a thin, elongated, approximately cylindrical sealed container that is slightly larger than the inner container 2. The outer container 3 has a first end 8 and a second end 10 in the longitudinal direction. The outer container 3 is translucent and flexible, and is made of a tube made of, for example, a silicone-based, polypropylene-based, polyethylene-based, vinyl-based, acrylic-based, polyester-based, polycarbonate-based, polyamide-based, polyimide-based, or fluoropolymer-based resin, an olefin-based, styrene-based, ester-based, amide-based, urethane-based, vinyl-based, or fluoropolymer-based elastomer, or a copolymer thereof. The inner container 2 is housed and sealed inside the outer container 3. In other words, the outer container 3 and the inner container 2 are nested within each other. The outer container 3 is flexible and can be bent non-destructively. For example, the outer container 3 is elastically deformable and has the property of returning to its original shape without breakage even when lightly bent.

[0052] The outer container 3 can also be made of shrink film. Examples of shrink films include heat-shrinkable films such as polyethylene terephthalate film, polystyrene film, polypropylene film, low-density polyethylene film, medium-density polyethylene film, high-density polyethylene film, low-density linear polyethylene film, cyclic polyolefin film, polyolefin films made from resins such as ethylene-propylene copolymer, ethylene-vinyl acetate copolymer, ionomer resin, ethylene-acrylic acid copolymer, and ethylene-methyl acrylate copolymer, modified polyolefin films made from resins such as chlorinated polyethylene and chlorinated polypropylene, films made from vinyl chloride-vinyl acetate copolymer resin, and acrylic resin films.

[0053] A liquid absorbent material 5 is provided in the gap 7 between the inner container 2 and the outer container 3. The liquid absorbent material 5 fills the entire gap 7, uniformly filling it. The liquid absorbent material 5 is made of an organic or inorganic material that has the property of absorbing liquid ink, such as fiber, cloth, paper, nonwoven fabric, sintered body, granules, spherical powder, plate-like powder, acicular powder, or a mixture thereof. Because the outer container 3 is translucent, the liquid absorbent material 5 is visible from outside the outer container 3. On the other hand, the inner container 2 is concealed by the liquid absorbent material 5 and is not visible from outside the outer container 3, or even if it is visible, it is only limited.

[0054] The size of the outer container 3 is not particularly limited as long as it is foldable, and can be appropriately selected depending on the location of use of the heat-sensitive indicator 1. For example, the total length of the outer container 3 can be about 30 mm to 150 mm, preferably about 50 mm to 100 mm, and the outer diameter can be about 0.05 to 0.2 times the total length. The wall thickness can be about 0.5 mm to 1 mm when a tube is used, and about 5 μm to 500 μm, preferably about 10 μm to 100 μm when a shrink film is used.

[0055] The size of the inner container 2 is not particularly limited as long as it satisfies the conditions that it fits inside the outer container 3, that it does not break when the outer container 3 is bent, and that there is a sufficient gap 7 for installing the liquid absorbent material 5. For example, the total length of the inner container 2 can be about 0.6 to 0.95 times the total length inside the outer container 3, the outer diameter can be about 0.2 to 0.8 times the inner diameter of the outer container 3, and the wall thickness can be about 0.01 mm to 0.1 mm.

[0056] The inner container 2 contains ink 6. Generally, ink is colored by dissolving or dispersing a dye or pigment in a solvent. The ink 6 in this embodiment is adjusted to have a desired melting point according to the "predetermined value" described above. Specifically, a solvent that melts at a temperature appropriate for the purpose is used as the solvent for the ink 6. The solvent can be appropriately selected from, for example, water, alcohols, esters, aliphatic hydrocarbons, aromatic hydrocarbons, ketones, ethers, and the like. Furthermore, the melting point can be adjusted by blending these or adding an additive such as sodium chloride to utilize molar freezing point depression. Below are examples of substances that can be used as solvents, along with their melting points (in parentheses).

[0057] (ultra-low temperature range) Propylene glycol (-59°C), butyl benzoate (-22°C), dibutyl oxalate (-29°C), dibutyl phthalate (-35°C), octyl acetate (-38°C), ethyl acetoacetate (-45°C), triethyl citrate (-46°C), diethyl malonate (-50°C), butyl acrylate (-64.6°C), amyl acetate (-71°C), butyl propionate (-75°C), octane (-56.8°C), heptane (-90.2°C), diethyl ketone (-42°C), diacetone alcohol (-47°C), hexyl ether (-43°C), diethylene glycol dibutyl ether (-60°C), ethylene glycol dibutyl ether (-69°C), butyl ether (-98°C).

[0058] (low temperature range) n-Nonyl alcohol (-5°C), ethylene glycol (-12.9°C), benzyl alcohol (-15.3°C), n-octyl alcohol (-16°C), cyclopentanol (-19°C), diethyl maleate (-10°C), castor oil (-10°C), dibutyl fumarate (-18°C), ethyl caprate (-20°C), methyl oleate (-20°C), dodecane (-9.6°C), dodecylbenzene (-7°C), acetonyl acetone (-6 to -5°C), methyl hexyl ketone (-16°C), cyclohexanone (-16.4°C).

[0059] (medium temperature range) Water (0°C), n-myristyl alcohol (38°C), cinnamyl alcohol (33°C), n-lauryl alcohol (24°C), cyclohexanol (23-25°C), n-decyl alcohol (6.9°C), oleic alcohol (0-5.0°C), ethyl stearate (34-38°C), dimethyl sebacate (29-31°C), methyl stearate (32°C), methyl myristate (18°C) ), diethyl tartrate (17°C), methyl laurate (4-5°C), 1-octadecane (27.8±0.7°C), 1-heptadecane (22°C), hexadecane (18°C), pentadecane (9.9°C), tetradecane (5.863°C), o-xylene (25°C), m-xylene (13°C), acetophenone (20.5°C), diphenyl ether (25-27°C), dioxane (11.8°C).

[0060] (high temperature range) Pentaerythritol (260°C), sorbitol (95°C), n-stearyl alcohol (59.4-59.8°C), trimethylolpropane (58°C), n-cetyl alcohol (49°C), amyl benzoate (260°C), phenyl benzoate (68-70°C), lauryl stearate (41°C), p-xylene (48°C), benzophenone (47.9°C), ethylene glycol diphenyl ether (94-96°C).

[0061] For example, by combining octane and heptane, a solvent with a melting point of around -70°C can be prepared. Also, by using propylene glycol, diethylene glycol dibutyl ether, ethylene glycol dibutyl ether, etc., a solvent with a melting point of around -60°C can be prepared. Furthermore, by using water as the main component, a solvent with a melting point of around 0°C can be prepared.

[0062] There is no particular limitation on the amount of ink 6 filled, and it can be, for example, 20% or more, 30% or more, 50% or more, 70% or more, 80% or more, etc. of the volume of the inner container 2. There is no particular limitation on the colorant contained in the ink 6, and various dyes and pigments can be used.

[0063] This section explains how to make and use (a method for monitoring the temperature of an article) the heat-sensitive indicator 1. As an example, we will explain how to monitor whether an article is kept at -70°C or below during transportation or storage.

[0064] First, ink 6 with a melting point of −70° C. is prepared. For example, an appropriate amount of octane (melting point: −56.8° C.) and heptane (melting point: −90.2° C.) is mixed to prepare a solvent with a melting point of −70° C., and an appropriate colorant is added to this to prepare the desired ink 6.

[0065] Ink 6 is filled into inner container 2, which is an ultra-thin glass ampoule made of borosilicate glass, and the glass ampoule is fused and sealed. The introduction of ink 6 into the glass ampoule and the fusion and sealing of the glass ampoule can be performed by known methods. Next, this ink-filled glass ampoule and a liquid absorbent material 5 made of fiber or the like are placed in outer container 3, which is a translucent, flexible, hard resin tube, and then sealed. This produces a heat-sensitive indicator 1 as shown in Figure 1(b). For example, a thin, cylindrical heat-sensitive indicator 1 with a total length of 75 mm and an outer diameter of 7.5 mm can be produced.

[0066] In preparation for use, the thermal indicator 1 is pre-cooled to -70°C or below, causing the ink 6 in the inner container 2 to become solid.

[0067] Next, the entire thermal indicator 1 is gently bent to break the inner container 2 without breaking the outer container 3 (breaking operation). That is, since the inner container 2 is breakable, it cannot withstand the bending and breaks (cracks). On the other hand, the outer container 3 is flexible and does not break. This exposes the ink 6 from the inner container 2 and makes contact with the liquid absorbent material 5. Furthermore, since the outer container 3 is elastically deformable, it quickly returns to its original shape after being bent. This breaking operation is preferably carried out in an environment maintained at an ultra-low temperature of -70°C or below to prevent the ink 6 from melting and returning to a liquid state before use of the thermal indicator 1. However, even in an environment above -70°C, it is possible to suppress the melting of the ink 6 to a practically acceptable level by quickly carrying out the breaking operation and immediately subjecting the ink 6 to the next process.

[0068] Once the ink 6 has been brought into contact with the liquid absorbent material 5 by the fracture operation, the heat-sensitive indicator 1 is immediately placed in the monitoring environment together with the item whose temperature is to be monitored. For example, it is placed in an insulated container filled with dry ice, together with the item, and the lid is then closed. This starts monitoring the temperature of the item. The heat-sensitive indicator 1 can be placed anywhere inside the insulated container, but it is desirable to place it in a location where it can be quickly seen by simply opening the lid without having to remove it from the insulated container again.

[0069] After a predetermined time has elapsed, the heat-sensitive indicator 1 is observed. For example, the insulated container packed with dry ice is temporarily opened, and the heat-sensitive indicator 1 is visually inspected inside the insulated container to observe the state of coloration of the liquid absorbent 5 by the ink 6, such as the presence and degree of coloration. Because the outer container 3 is translucent, the state of coloration of the liquid absorbent 5 can be easily observed. If the liquid absorbent 5 is not colored, this indicates that the ink 6 remained solid and did not melt, and it is determined that a temperature of −70°C or below was maintained during temperature monitoring. On the other hand, if the liquid absorbent 5 is colored, this indicates that the ink 6 melted during temperature monitoring, and it is determined that the temperature rose to −70°C or above during temperature monitoring, indicating a temperature deviation. The degree of temperature deviation can also be evaluated based on the intensity of the coloration. If the liquid absorbent 5 is not colored and the ink 6 remained solid and did not melt, the liquid absorbent 5 may be returned to the insulated container at −70°C or below and temperature monitoring may be continued. Observation after a predetermined time has elapsed is preferably carried out in an environment maintained at an ultra-low temperature of -70°C or below to prevent the ink 6 from melting and returning to a liquid state when the thermal indicator 1 is removed. However, even if the indicator is removed to an environment above -70°C, melting of the ink 6 can be suppressed to a practically acceptable level by quickly observing the indicator and immediately placing it in an ultra-low temperature environment.

[0070] In the above-described example, the heat-sensitive indicator 1 was pre-frozen before the inner container 2 was destroyed, but pre-freezing can be omitted. For example, while the ink 6 is in a liquid state, the heat-sensitive indicator 1 is bent to destroy the inner container 2, and then immediately placed in a specified test environment (for example, below -70°C). At this time, a small amount of ink 6 may be absorbed into the liquid absorbent material 5 before monitoring begins, but by immediately placing it in the test environment, it is possible to suppress unnecessary coloring of the liquid absorbent material 5 before use to a level that is practically acceptable.

[0071] In the above-described embodiment, the liquid absorbent 5 (fiber, cloth, paper, nonwoven fabric, sintered body, granules, spherical powder, plate-like powder, acicular powder, a mixture thereof, etc.) is provided directly in the outer container 3, but the liquid absorbent 5 may also contain a solvent that is miscible with the ink 6. According to this embodiment, when the liquid ink 6 transfers to the liquid absorbent 5, it is easily diffused throughout the liquid absorbent 5 via the solvent contained in the liquid absorbent 5. As a result, the coloring state can be more easily determined. The melting point of the solvent is preferably equal to or lower than the melting point of the ink 6. This ensures that the solvent is always in a liquid state under temperature conditions where the ink 6 melts. The solvent used in the ink 6 can also be used as it is as a solvent having the same melting point as the ink 6. With this configuration, the ink 6 can more easily transfer to the liquid absorbent 5 and can more easily diffuse throughout the liquid absorbent 5 via the solvent contained in the liquid absorbent 5.

[0072] In the above-described embodiment, the ink 6 is heat-fusible. However, a non-heat-fusible ink 6 may be enclosed in the inner container 2, and the liquid absorbent 5 may contain a heat-fusible solvent. For example, the ink 6 may be one that is always liquid at the temperature of the test environment. Meanwhile, the liquid absorbent 5 may be a heat-fusible solvent, i.e., a heat-fusible substance that has a desired melting point and, in its liquid state, can act as a solvent for the colorant contained in the ink 6. With this configuration, if the temperature exceeds a predetermined value during temperature monitoring, the heat-fusible substance contained in the liquid absorbent 5 liquefies, and the ink 6 diffuses and mixes with the heat-fusible substance and is absorbed into the liquid absorbent 5, thereby coloring the liquid absorbent 5. On the other hand, if the temperature is maintained below a predetermined value, the heat-fusible substance contained in the liquid absorbent 5 remains solid, so the ink 6 does not transfer to the liquid absorbent 5, and the liquid absorbent 5 remains uncolored. The heat-sensitive indicator of this embodiment can also be used in the same manner as described above.

[0073] Either or both of the outer surface of the inner container 2 and the inner surface of the outer container 3 may be matte-finished. Generally, a dry matte-finished surface is opaque and opaque, but when wetted with liquid, it becomes more transparent and becomes see-through. This property can be utilized to improve the ease of handling of the heat-sensitive indicator 1. That is, by making the outer surface of the inner container 2 or the inner surface of the outer container 3 matte-finished, the inside of the inner container 2 or the outer container 3 can be easily concealed when the heat-sensitive indicator 1 is not in use. On the other hand, after using the heat-sensitive indicator 1, when the liquid ink 6 or the solvent in which the ink 6 has diffused or mixed comes into contact with the matte-finished surface, the surface becomes wet and see-through, allowing the color state of the liquid absorbent material 5 to be easily confirmed.

[0074] Next, a second embodiment of the present invention will be described. A heat-sensitive indicator 11 according to the second embodiment shown in Figures 2(a) and 2(b) includes the same inner container 2, outer container 3, liquid absorbent material 5, and ink 6 as the heat-sensitive indicator 1 according to the first embodiment (Figures 1(a) and 1(b)), but also includes an intermediate container 12. The liquid absorbent material 5 is provided in a gap 14 between the intermediate container 12 and the outer container 3.

[0075] The intermediate container 12 is provided inside the outer container 3, more specifically, in the gap 7 between the inner container 2 and the outer container 3. The intermediate container 12 is a cylindrical member that is slightly larger than the inner container 2, and accommodates most of the inner container 2. The intermediate container 12 is a bottomed member that is open on the first end 8 side and closed on the second end 10 side. After the inner container 2 is broken, the ink 6 inside can reach the liquid absorbent material 5 through the opening 15 of the intermediate container 12. On the other hand, because the second end 10 side of the intermediate container 12 is closed, the ink 6 will not be released from the second end 10 side. Like the outer container 3, the intermediate container 12 is flexible and can be bent non-destructively.

[0076] The heat-sensitive indicator 11 of the second embodiment can be used in the same manner as the heat-sensitive indicator 1 of the first embodiment. During the breaking operation, the entire heat-sensitive indicator 11 is gently bent to break the inner container 2 without breaking the outer container 3 and the intermediate container 12. Here, since the heat-sensitive indicator 11 includes the intermediate container 12 having an opening 15, the liquid ink 6 reaches the liquid absorbent material 5 through the opening 15. That is, the ink 6 is guided toward the first end 8 and contacts the liquid absorbent material 5 from the first end 8 side. Therefore, the ink 6 diffuses in the liquid absorbent material 5 from the first end 8 side toward the second end 10 side. According to this embodiment, the degree of diffusion of the ink 6, i.e., the degree of ink coloring, can be easily grasped.

[0077] By understanding the degree of ink coloration, it is possible to determine not only whether the environment in which the article is placed has exceeded a predetermined value, but also to evaluate the degree of deviation if the temperature exceeds the predetermined value. For example, the degree of temperature deviation can be evaluated by measuring the diffusion distance (mobility) of ink 6 from first end 8 to second end 10. In other words, it can be evaluated that a small diffusion distance indicates a small degree of temperature deviation, and a large diffusion distance indicates a large degree of temperature deviation.

[0078] As in the first embodiment, in the second embodiment, the liquid absorbent 5 may contain a solvent that is miscible with the ink 6. Alternatively, a non-thermofusible ink 6 may be enclosed in the inner container 2, and the liquid absorbent 5 may contain a thermofusible solvent.

[0079] Either or both of the inner and outer surfaces of the intermediate container 12 may be matte-finished, which makes it possible to easily conceal the inside of the intermediate container 12 when the heat-sensitive indicator 11 is not in use.

[0080] Next, a third embodiment of the present invention will be described. A heat-sensitive indicator 21 according to the third embodiment, shown in FIGS. 3(a) and 3(b), includes an inner container 2, an outer container 3, a liquid absorbent material 5, and ink 6 similar to those of the heat-sensitive indicator 1 according to the first embodiment (FIGS. 1(a) and 1(b)). However, the inner container 2 is positioned closer to the first end 8. The overall length of the inner container 2 according to this embodiment is smaller than that of the first embodiment, being approximately 0.3 to 0.6 times the overall length of the interior of the outer container 3. The inner container 2 occupies only the region from the first end 8 to the center of the outer container 3. The position of the inner container 2 is preferably as close to the first end 8 as possible, as long as the fracturing operation is possible. Furthermore, the end of the inner container 2 on the second end 10 side is preferably closer to the first end 8 than the center of the outer container 3.

[0081] The heat-sensitive indicator 21 of this embodiment can be used in the same manner as the heat-sensitive indicator 1 of the first embodiment. Here, in the heat-sensitive indicator 21, the inner container 2 is installed biased toward the first end 8, so the liquid ink 6 comes into contact with the liquid absorbent material 5 at a position biased toward the first end 8. Therefore, diffusion of the ink 6 begins from a position biased toward the first end 8, and the diffusion of the ink 6 progresses toward the second end 10. As in the second embodiment, according to this embodiment, the degree of diffusion of the ink 6, i.e., the degree of coloration of the ink, can be easily grasped.

[0082] In this embodiment, the intermediate container 12 employed in the second embodiment may be further provided. That is, the inner container 2 may be disposed at a position offset toward the first end 8, and the inner container 2 may be contained within the intermediate container 12.

[0083] As in the first embodiment, in the third embodiment, the liquid absorbent 5 may contain a solvent that is miscible with the ink 6. Alternatively, a non-thermofusible ink 6 may be enclosed in the inner container 2, and the liquid absorbent 5 may contain a thermofusible solvent.

[0084] Next, a fourth embodiment of the present invention will be described. A heat-sensitive indicator 31 shown in Fig. 4(a) has the same inner container 2, outer container 3, liquid absorbent material 5, ink 6, and intermediate container 12 as the heat-sensitive indicator 11 according to the second embodiment (Figs. 2(a) and 2(b)), but also has an outer shell 32. A heat-sensitive indicator 41 shown in Fig. 4(b) has the same inner container 2, outer container 3, liquid absorbent material 5, and ink 6 as the heat-sensitive indicator 21 according to the third embodiment (Figs. 3(a) and 3(b)), but also has an outer shell 32.

[0085] The outer skin 32 is provided in close contact with the outer surface of the outer container 3, and covers the entire outer container 3. The outer skin 32 includes a transparent portion that allows the outer container 3 to be seen from the outside, and an opaque portion that prevents the outer container 3 from being seen from the outside. The presence or absence and degree of coloring of the liquid absorbent material 5 can be seen only from the transparent portion. The outer skin 32 can also be said to be a member that allows only the necessary parts of the outer container 3 to be seen, while hiding the unnecessary parts. The outer skin 32 may cover only a part of the outer container 3.

[0086] The outer cover 32 can be made of, for example, shrink film or wrapping paper. Examples of shrink film include those mentioned above. The film can be partially colored with a pigment or the like to form transparent and opaque areas.

[0087] It is also possible to partially print on the outer surface of the outer container 3, and to use this printed portion as the outer skin 32. Then, a transparent portion and a non-transparent portion can be formed by the non-printed portion and the printed portion.

[0088] The transparent portions of the outer shell 32 that allow the outer container 3 to be seen from the outside function as visible portions. The opaque portions function as concealed portions. Specific examples of visible portions will be described below with reference to Figs. 5, 6(a) to 6(c), and 7. Note that these figures schematically illustrate the appearance of the heat-sensitive indicators 31, 41, with the left side being the first end 8 side and the right side being the second end 10 side. Note that the visible portions can also be called window portions.

[0089] The visible portion 34 shown in FIG. 5 is linear and consists of a single linear window extending from the first end 8 toward the second end 10. The visible portion 34 allows the degree of coloring by the ink 6 (the mobility of the ink 6) to be confirmed along the length direction. A plurality of linear visible portions 34 may be provided in the circumferential direction to form a vertical striped pattern. Alternatively, the visible portion 34 may be a single spiral curve extending from the first end 8 toward the second end 10.

[0090] 6(a) to 6(c) show examples in which a plurality of visible portions are provided in the length direction. 6(a) are ring-shaped windows along the circumferential direction of the outer skin 32. The visible portions 35a to 35e are arranged in this order from the first end 8 toward the second end 10 at predetermined intervals. The visible portions 36a to 36e shown in Figure 6(b) are circular windows, and are arranged in this order on a straight line at predetermined intervals from the first end 8 to the second end 10. The visible portions 36a to 36e may also be other shapes, for example, polygons such as triangles or rectangles. The visible portions 37a to 37e shown in Fig. 6(c) are windows in the shape of the letters A, B, C, D, and E, respectively. The visible portions 37a to 37e are arranged in this order on a straight line at predetermined intervals from the first end 8 toward the second end 10. The visible portions 36a to 36e may also be other letters or symbols, such as numbers.

[0091] In the fourth embodiment, the diffusion of the ink 6 proceeds from the first end 8 toward the second end 10, and the degree of coloring by the ink 6 (the mobility of the ink 6) can be grasped in stages according to the visible portions 35a-35e, 36a-36e, and 37a-37e. Using FIG. 6(a) as an example, if none of the visible portions 35a-35e are colored, it can be determined that there was no temperature excursion. If only the visible portion 35a is colored, it can be determined that a temperature excursion occurred but for a short period of time. If the visible portions 35a, 35b, and 35c are colored, it can be determined that the temperature excursion lasted for a medium period of time. If all of the visible portions 35a-35e are colored, it can be determined that the temperature excursion lasted for a long period of time.

[0092] FIG. 7 shows another example in which multiple visible portions are provided in the longitudinal direction. The visible portions 38a to 38e shown in FIG. 7 are circular windows similar to those in FIG. 6(b), but some of them are pre-colored. Specifically, the visible portion 38a is colored light blue. The visible portions 38b, 38c, and 38d are not colored. The visible portion 38e is colored light red. Yellow ink is used as the ink 6. As the yellow ink 6 diffuses from the first end 8 toward the second end 10, the visible portion 38a turns green when it reaches the position of the visible portion 38a. As the ink 6 diffuses further and reaches the positions of the visible portions 38b, 38c, and 38d, the visible portions 38b, 38c, and 38d turn yellow. As the ink 6 diffuses further and reaches the position of the visible portion 38e, the visible portion 38e turns orange. According to this embodiment, the degree of coloring by the ink 6 (the mobility of the ink 6) can be grasped in stages, and the degree of coloring can be grasped using three colors like a traffic light. The coloring of the visible portion and the ink colors used are not limited to the example in FIG. 7, and any color can be selected and combined. Furthermore, the visible portions 38a to 38e may be other shapes, for example, polygons such as triangles and rectangles, or may be letters or symbols.

[0093] When multiple visible portions are provided, the number of visible portions is not limited to five, as long as it is two or more. Furthermore, when multiple visible portions are provided, the shapes and sizes of the respective visible portions do not have to be the same, and visible portions of different shapes and sizes may be mixed. Furthermore, continuous visible portions extending in the length direction as shown in Fig. 5 may be combined with independent visible portions as shown in Figs. 6(a) to (c) and 7.

[0094] To make it easier to grasp the mobility of the ink 6, a scale extending in the length direction, like that engraved on a ruler, may be provided. For example, a visible portion in the shape of a scale may be provided. Also, a colored scale, printed or otherwise, may be provided alongside an existing visible portion (e.g., visible portion 34 in FIG. 5). Furthermore, of the scales engraved at predetermined intervals, some may be visible and the rest may be colored. For example, of a scale in 1 mm increments like that on a ruler, the main scales at 5 mm or 10 mm intervals may be made up of visible portions, and the secondary scales may be printed.

[0095] The visible portion may be in the form of a one-dimensional code (barcode) or a two-dimensional code such as a QR code (registered trademark), which makes it easier to read the temperature monitoring results by machine.

[0096] As long as the outer container 3 can be seen, the visible portion may be colorless and transparent, colored and transparent, or colored and translucent. For example, the visible portion may be made translucent by a collection of minute dots that are indistinguishable from the naked eye. A gradation in which the size of the minute dots changes continuously may also be used.

[0097] The heat-sensitive indicator of the present invention may be provided with a holding member that holds the heat-sensitive indicator in a vertical position. For example, in the second and third embodiments, in which the ink 6 diffuses from the first end 8 toward the second end 10, it is preferable to use the heat-sensitive indicator while maintaining the indicator in a vertical position with the first end 8 at the bottom and the second end 10 at the top. Maintaining this vertical position makes it easier for the liquid ink 6 to accumulate on the first end 8 side, reducing variation in the progress of coloring.

[0098] Specific examples of the holding member are shown in Figures 8(a) to 8(g). In Figures 8(a) to 8(g), the heat-sensitive indicator 21 of the third embodiment (Figures 3(a) and 3(b)) and the heat-sensitive indicator 41 of the fourth embodiment (Figure 4(b)) are shown as representative examples and are drawn in a schematic manner. Of course, these holding members can also be applied to the heat-sensitive indicators of the other embodiments.

[0099] The holding member 43 in Figure 8(a) is configured with a hook hole. The holding member 43 is provided on the second end portion 10 side. By using the hook hole to hang the thermal indicator 21, 41, it is possible to keep it in a vertical position.

[0100] The holding member 44 in Fig. 8(b) is configured as a handle. The holding member 44 is provided on the second end portion 10 side. The heat-sensitive indicator 21, 41 can be hung from the handle to keep it in a vertical position. The handle may be a string-like one.

[0101] The holding member 45 in Figure 8(c) is configured as a clip-like fastener. The holding member 45 is provided on the second end 10 side. The holding member 45 can be hooked onto an appropriate support to keep the thermal indicator 21, 41 in a vertical position. For example, a fastener having a similar configuration to a clip used in a writing instrument can be used.

[0102] The holding member 46 in Figure 8(d) is configured as an openable and closable clip-like fastener. The holding member 45 is provided on the second end 10 side. By clamping an appropriate support with the holding member 45, the thermal indicator 21, 41 can be kept in a vertical position. The fastener can be similar to a clip with a torsion spring, which is used in stationery and the like.

[0103] The holding member 47 in Figure 8(e) is made up of a suction cup. The holding member 47 is provided on the side of the heat-sensitive indicator. The suction cup can be attached to an appropriate support to keep the heat-sensitive indicator 21, 41 in a vertical position.

[0104] The holding member 48 in Figure 8(f) is made up of a base. The holding member 48 is provided on the first end 8 side, allowing the thermal indicator 21, 41 to stand upright in the vertical direction. The base may be a gusset-like structure that can be unfolded to form a base when in use.

[0105] 8(g) is made up of legs. The holding member 49 is provided on the first end 8 side, and allows the heat sensitive indicators 21, 41 to stand upright in the vertical direction.

[0106] The holding members 43 to 49 shown in Figures 8(a) to 8(g) can be provided on the outer container 3 or the outer shell 32. The holding members 43 to 49 may be formed integrally with the outer container 3 or the outer shell 32, or may be attached as separate members. When the outer shell 32 is made of shrink film, elements (such as holes) that form the holding members may be provided in advance on the end side of the shrink film.

[0107] In the above-described embodiment, a reversible temperature indicator whose color tone reversibly changes depending on the temperature may be further provided on the outermost surface of the heat-sensitive indicator. For example, if the environmental temperature in which the item is placed must be maintained at -20°C or below, a reversible temperature indicator whose color tone reversibly changes around -20°C may be provided on the outermost surface of the heat-sensitive indicator. This makes it easy to confirm that pre-cooling was performed before using the heat-sensitive indicator and that the temperature at the time of pre-cooling is currently being maintained. An example of a reversible temperature indicator is one in which ink whose color tone reversibly changes depending on the temperature is printed on a portion of the outermost surface of the heat-sensitive indicator. Another example is a sticker-type thermometer that is attached to the surface of an object.

[0108] A dedicated protective jig may be used during the breaking operation to prevent fragments generated when breaking the inner container 2 from piercing the outer container 3. An example of such a protective jig is a jig for positioning the bending portion of the heat-sensitive indicator. [Explanation of symbols]

[0109] 1, 11, 21, 31, 41 Thermal indicator 2 Inner container 3 Outer container 5 Liquid absorbent material 6 Ink 7. Gap 8 First end 10 Second end 12 Intermediate container 14 Gap 15 Opening 32 Hull 34 Visible part 35a~35e, 36a~36e, 37a~37e, 38a~38e Visible part 43, 44, 45, 46, 47, 48, 49 Retaining members

Claims

1. A thermal indicator that irreversibly indicates that a temperature has reached or exceeded a predetermined value, an inner container having breakability and containing ink therein; an outer container having translucency and flexibility, and having the inner container enclosed therein; A liquid absorbent material is provided in the gap between the inner container and the outer container, the ink is adjusted to have a desired melting point according to the predetermined value, The inner container can be fractured by non-destructively bending the outer container, When the ink becomes liquid after the inner container is broken, the ink is absorbed into the liquid absorbent material, and the color of the liquid absorbent material becomes visible from outside the outer container, A heat-sensitive indicator characterized in that the liquid absorbent material holds a solvent that is miscible with the liquid ink.

2. A thermal indicator that irreversibly indicates that a temperature has reached or exceeded a predetermined value, an inner container having breakability and containing ink therein; an outer container having translucency and flexibility, and having the inner container enclosed therein; A liquid absorbent material is provided in the gap between the inner container and the outer container, the liquid absorbent holds a heat-fusible substance that has a desired melting point corresponding to the predetermined value and that can be a solvent for the colorant contained in the ink in a liquid state; The inner container can be fractured by non-destructively bending the outer container, A heat-sensitive indicator characterized in that when the heat-fusible substance becomes liquid after the inner container is broken, the ink is absorbed into the liquid absorbent material, making the color of the liquid absorbent material visible from outside the outer container.

3. 3. The heat-sensitive indicator according to claim 1, wherein the inner container is concealed by the liquid absorbent material and is not visible from outside the outer container.

4. A heat-sensitive indicator that irreversibly indicates that a temperature has reached a predetermined value or higher, an inner container having breakability and containing ink therein; an outer container having translucency and flexibility, and having the inner container enclosed therein; A liquid absorbent material is provided in the gap between the inner container and the outer container, the ink is adjusted to have a desired melting point according to the predetermined value, The inner container can be fractured by non-destructively bending the outer container, When the ink becomes liquid after the inner container is broken, the ink is absorbed into the liquid absorbent material, and the color of the liquid absorbent material becomes visible from outside the outer container, A heat-sensitive indicator, wherein at least one of the outer surface of the inner container and the inner surface of the outer container is matte-finished.

5. 5. The heat-sensitive indicator according to claim 1, wherein at least one of the outer surface of the inner container and the inner surface of the outer container is matte-finished.

6. 6. The heat-sensitive indicator according to claim 1, wherein the outer container is made of a silicone resin.

7. 7. The heat sensitive indicator according to claim 1, wherein the inner container and the outer container are both elongated.

8. A heat-sensitive indicator that irreversibly indicates that a temperature has reached a predetermined value or higher, an inner container having breakability and containing ink therein; an outer container having translucency and flexibility, and having the inner container enclosed therein; A liquid absorbent material is provided in the gap between the inner container and the outer container, the ink is adjusted to have a desired melting point according to the predetermined value, The inner container can be fractured by non-destructively bending the outer container, When the ink becomes liquid after the inner container is broken, the ink is absorbed into the liquid absorbent material, and the color of the liquid absorbent material becomes visible from outside the outer container, the outer container has an elongated shape having a first end and a second end in a longitudinal direction; An intermediate container that accommodates the inner container is further provided within the outer container, the intermediate container has an open first end and a closed second end, A heat-sensitive indicator characterized in that the liquid absorbent material is provided in a gap between the intermediate container and the outer container.

9. the outer container has an elongated shape having a first end and a second end in a longitudinal direction; An intermediate container that accommodates the inner container is further provided within the outer container, the intermediate container has an open first end and a closed second end, 8. The heat-sensitive indicator according to claim 1, wherein the liquid absorbent material is provided in a gap between the intermediate container and the outer container.

10. the outer container has an elongated shape having a first end and a second end in a longitudinal direction; 10. The heat sensitive indicator according to claim 1, wherein the inner container is disposed at a position biased toward the first end.

11. Further provided is an outer skin covering a part or all of the outer surface of the outer container, A heat-sensitive indicator according to any one of claims 8 to 10, characterized in that the outer skin forms a visible portion that allows the outer container to be seen from the outside and a concealed portion that prevents the outer container from being seen from the outside.

12. 12. The heat sensitive indicator according to claim 11, wherein the visible portion is a line extending from the first end toward the second end.

13. 12. The heat sensitive indicator according to claim 11, wherein the visible portion comprises a plurality of visible portions, the plurality of visible portions being arranged from the first end toward the second end.

14. 14. A heat-sensitive indicator according to claim 1, further comprising a holding member for holding the heat-sensitive indicator in a vertical position.

15. 15. The heat-sensitive indicator according to claim 1, further comprising a reversible temperature indicator on the outermost surface, the color of which changes reversibly depending on the temperature.

16. 16. The heat-sensitive indicator according to claim 1, wherein the melting point is 0° C. or lower.

17. 16. The heat-sensitive indicator according to claim 1, wherein the melting point is −70° C. or lower.

18. A method for monitoring the temperature of an object, which monitors the temperature of an environment in which an object is placed, comprising: Providing a heat sensitive indicator according to any one of claims 1 to 17; fracturing the inner container; placing the thermal indicator in the environment along with an item whose temperature is to be monitored; and a step of checking the coloration state of the liquid absorbent material in the heat-sensitive indicator after a predetermined time has elapsed; 1. A method for monitoring the temperature of an article, comprising:

19. 20. The method of claim 18, further comprising the step of cooling the heat sensitive indicator to a temperature below the predetermined value before fracturing the inner container.

20. A thermosensitive indicator according to any one of claims 8 to 13 is used, A temperature monitoring method for an item as described in claim 18 or 19, characterized in that when checking the coloration state of the liquid absorbent material, the temperature monitoring results are evaluated based on the degree of coloration from the first end to the second end.

21. 21. The method for monitoring the temperature of an article according to claim 18, wherein the predetermined value is selected from temperatures below 0°C.

22. The method for monitoring the temperature of an article according to any one of claims 18 to 20, wherein the predetermined value is selected from temperatures of -70°C or less.

Images