CONSTANT-TEMPERATURE STORAGE CONTAINER AND TRANSPORTATION METHOD

Abstract

Disclosed is a container that is capable of maintaining articles requiring thermal management at a prescribed temperature without being influenced by the outside air temperature, and that is capable of storing and transporting the articles. The constant-temperature storage container is equipped with a heat-insulating box, and two or more types of cold-storing materials or heat-storing materials disposed therein; has a latent-heat first cold-storing or heat-storing material (a) disposed in a solid state adjacent to an article being kept cool or warm, and a latent-heat second cold-storing or heat-storing material (b) disposed in a molten state on the exterior of the first cold-storing or heat-storing material (a); and the solidifying and melting temperature of the first cold-storing or heat-storing material (a) exceeds 0° C. The constant-temperature storage container is capable of maintaining the article being kept cool or warm in an arbitrary temperature range exceeding 0° C. for long periods of time.

Description

TECHNICAL FIELD

The present invention relates to a container that can maintain articles requiring thermal management at a predetermined temperature over long periods of time without being influenced by the outside air temperature and that can store and transport the articles, and more specifically, it relates to a container that can maintain various articles requiring thermal management, such as pharmaceutical products, medical devices, specimens, organs, chemical substances, and foods at a predetermined temperature of more than 0° C. and that can store and transport the articles.

BACKGROUND ART

Some of pharmaceutical products, specimens, foods, and the like that are handled at, for example, hospitals and supermarkets need to be kept cold or warm in an effective predetermined temperature range in order to ensure quality during transportation and conveyance. As a method for keeping such an article such as pharmaceutical products cold or warm, there has been conventionally known a method of placing a cold-storing material or a heat-storing material that is previously solidified or molten in a heat-insulating container and storing the article in the container to keep the article cold or warm using latent heat of melting of the cold-storing material or the heat-storing material.

In order to maintain an article to be kept cold or warm (hereinafter, also referred to as “article under thermal management”) in a predetermined temperature range over long periods of time, for example, it is required to use a cold-storing material or a heat-storing material having large latent heat of melting and to increase the thickness of a heat-insulating container. A conventionally used cold-storing material that has large latent heat of melting and that is inexpensive and safe is water. However, water has a melting temperature of 0° C., and thus the temperature in a heat-insulating container may be reduced to near 0° C. On this account, the case of thermal management in a temperature region more than 0° C. employs a method of placing a transportation object apart from a heat-storing material mainly containing water or a method of blocking heat transfer by a heat insulating material. However, even when such a method is employed, the temperature in a heat-insulating container is reduced to near 0° C. in some cases depending on variation of the outside air temperature.

In order to keep the inside at a temperature suited for ambient temperature storage, there is disclosed a thermostatic box that uses a heat-storing material having a melting point of 10 to 25° C. and that uses the heat-storing material in a previously frozen state when the outside air temperature is higher than the melting point of the heat-storing material or uses the heat-storing material in a previously thawed state when the outside air temperature is lower than the melting point of the heat-storing material (see Patent Document 1). The thermostatic box can achieve the thermal management in a temperature region more than 0° C. but cannot achieve accurate thermal management over long periods of time.

Meanwhile, there is also disclosed a thermostatic box that includes a plurality of kinds of heat-storing materials having temperatures different from each other in a heat-insulating box, and places a heat-storing material having a lower temperature on an outer side of a heat-storing material having a higher temperature when the outdoor temperature is high, and places a heat-storing material having a higher temperature on an outer side of a heat-storing material having a lower temperature when the outdoor temperature is low, thereby maintaining the inside temperature in a predetermined range depending on an outdoor temperature condition (see Patent Document 2). However, such a simple combination of heat-storing materials having temperatures different from each other cannot achieve accurate thermal management over long periods of time.

CITATION LIST

Patent Literature

• Patent Document 1: JP-A No. 2001-63776
• Patent Document 2: JP-A No. 9-68376

SUMMARY OF INVENTION

Technical Problem

As described above, there has been no container that can maintain articles requiring thermal management at a predetermined temperature over long periods of time without being influenced by the outside air temperature and that can store and transport the articles. In particular, in the case of air transportation, the thermal management is required for about 72 hours, but there has been no constant-temperature storage container that can achieve thermal management over a long time of 72 hours without being influenced by the outside air temperature.

Solution to Problem

In order to solve the above problems, the present invention can achieve accurate thermal management over long periods of time by stacking and placing two or more kinds of latent heat cold-storing materials or heat-storing materials having phase states different from each other.

Namely, the constant-temperature storage container of the present invention is a constant-temperature storage container that includes a heat-insulating box and two or more kinds of cold-storing materials or heat-storing materials placed in the heat-insulating box. A latent heat first cold-storing material or heat-storing material (a) in a solidified state is placed adjacent to an article to be kept cold or warm, a latent heat second cold-storing material or heat-storing material (b) in a molten state is placed on an outer side of the first cold-storing material or heat-storing material (a), and the first cold-storing material or heat-storing material (a) has a solidifying and melting temperature of more than 0° C.

In the present invention, the constant-temperature storage container may further include a third cold-storing material or heat-storing material (c). The third cold-storing material or heat-storing material (c) is placed on an outer side of the second cold-storing material or heat-storing material (b) and is in a lower temperature state than the second cold-storing material or heat-storing material (b).

The present invention can provide the constant-temperature storage container that can achieve accurate thermal management in a container management temperature A (° C.) ranging from 1 to 30° C.

In the present invention, the first cold-storing material or heat-storing material (a) and the second cold-storing material or heat-storing material (b) preferably have a solidifying and melting temperature of (A−3)° C. to (A+3)° C., and the third cold-storing material or heat-storing material (c) preferably has a solidifying and melting temperature of (A−10)° C. to (A−5)° C., where the container management temperature is A (° C.).

The first cold-storing material or heat-storing material (a) and the second cold-storing material or heat-storing material (b) preferably have a solidifying and melting temperature of 2° C. to 8° C., and the third cold-storing material or heat-storing material (c) preferably has a solidifying and melting temperature of −5 to 0° C.

The first cold-storing material or heat-storing material (a) and the second cold-storing material or heat-storing material (b) are preferably composed of a heat-storing material composition containing an aqueous solution of at least one salt, the salt being insoluble in a polyalkylene glycol and soluble in water, and a polyalkylene glycol. The third cold-storing material or heat-storing material (c) is preferably a cold-storing material mainly containing water.

In the constant-temperature storage container as above of the present invention, the article to be kept cold or warm may be stored in a heat-insulating inner box.

An article transportation method of the present invention includes transporting an article to be kept cold or warm stored in the constant-temperature storage container. In the constant-temperature storage container, the latent heat second cold-storing material or heat-storing material (b) in a molten state is placed on an outer side of the latent heat first cold-storing material or heat-storing material (a) in a solidified state where an outside air temperature of the container is lower than the container management temperature A. Furthermore, an article transportation method of the present invention includes transporting an article to be kept cold or warm stored in the constant-temperature storage container that further includes the third cold-storing material or heat-storing material (c) where an outside air temperature of the container is higher than the container management temperature A.

Advantageous Effects of Invention

The constant-temperature storage container and the transportation method of the present invention as above can maintain articles requiring thermal management over long periods of time at a predetermined temperature without being influenced by the outside air temperature and can store and transport the articles.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a schematic view showing a configuration of cold-storing materials or heat-storing materials of a package for measurement that is used in Example 4 and that is a constant-temperature storage container of a first embodiment of the present invention.

FIG. 2 is a schematic view showing a configuration of cold-storing materials or heat-storing materials of a package for measurement that is used in Example 1 and that is a constant-temperature storage container of a second embodiment of the present invention.

FIG. 3 is a schematic view showing a configuration of cold-storing materials or heat-storing materials of a package for measurement that is used in Example 5 and that is the constant-temperature storage container of the first embodiment of the present invention.

FIG. 4 is a graph showing temperature change in an inner box 5 in Example 1.

FIG. 5 is a graph showing temperature change in an inner box 5 in Example 2.

FIG. 6 is a graph showing temperature change in an inner box 5 in Example 3.

FIG. 7 is a graph showing temperature change in an inner box 5 in Comparative Example 1.

FIG. 8 is a graph showing temperature change in an inner box 5 in Example 4.

FIG. 9 is a graph showing temperature change in an inner box 5 in Example 5.

FIG. 10 is a graph showing temperature change in an inner box 5 in Comparative Example 2.

DESCRIPTION OF EMBODIMENTS

A constant-temperature storage container of the present invention includes a heat-insulating box and two or more kinds of latent heat cold-storing materials or heat-storing materials that are in different phase states and that are placed in the box. The constant-temperature storage container uses a cold insulator or warm insulator in a solidified state having a solidifying and melting temperature of more than 0° C. as a first cold insulator or warm insulator placed adjacent to an article to be kept cold or warm. The constant-temperature storage container can maintain the article to be kept cold or warm in an arbitrary temperature range more than 0° C. over long periods of time.

In the present invention, the cold-storing material or heat-storing material is a cold-storing component or heat-storing component that is filled in, for example, a plastic container or a film bag. The latent heat cold-storing material or heat-storing material is a cold-storing material or heat-storing material that uses thermal energy associated with phase transition. The latent heat cold-storing material or heat-storing material uses the thermal energy that is absorbed when the phase state of the cold-storing component or heat-storing component is transformed from a solidified state (solid) to a molten state (liquid) or uses the thermal energy that is discharged when the phase state is transformed from a molten state (liquid) to a solidified state (solid).

In the present invention, the solidifying and melting temperature of the cold-storing material or heat-storing material is a temperature at which the phase state is changed from a solidified state (solid) to a molten state (liquid) or changed from a molten state (liquid) to a solidified state (solid). For example, water has a solidifying and melting temperature of 0° C. The solidifying and melting temperature of the cold-storing material or heat-storing material can be determined, for example, by differential scanning calorimetry using a differential scanning calorimeter DSC (SEIKO 6200 manufactured by Seiko Instruments Inc.) where 28 mg of a cold-storing material component or heat-storing material component is filled in a measurement pan and heated from −20° C. at a temperature rise rate of 4° C./minute. That is, the solidifying and melting temperature of a cold-storing material or heat-storing material can be determined as a peak temperature value in the obtained chart (when a plurality of peaks are observed, the peak having a maximum peak height is regarded as the peak temperature value).

In the present invention, the cold-storing material or heat-storing material having a solidifying and melting temperature of more than 0° C. means that 50% by weight or more of the cold-storing component or heat-storing component has a solidifying and melting temperature of more than 0° C. Hence, for example, a cold-storing material or heat-storing material containing water in excess of 50% is usually excluded. However, even when a cold-storing material or heat-storing material contains water in excess of 50%, any material containing water in excess of 50% by weight when molten, for example, an inorganic salt hydrate (such as sodium sulfate decahydrate), may have a solidifying and melting temperature of more than 0° C.

In the present invention, the phase state represents typical solid, liquid, and gas states, but the present invention uses the phase states of solid and liquid for reducing a container size. The phase state of a cold-storing material or heat-storing material represents the phase of 50% by weight or more of the material. For example, the phase state of a cold-storing material or heat-storing material in which 80% by weight of the material is solid and 20% by weight of the material is liquid is solid (solidified state).

FIG. 1 shows a first embodiment of the constant-temperature storage container of the present invention. The constant-temperature storage container 1A of the first embodiment is a container suited for environments where an external temperature of the container is lower than a predetermined container management temperature. The constant-temperature storage container 1A is a constant-temperature storage container that includes a heat-insulating box 2 composed of a box body 3 and a cover 4 and two or more kinds of cold-storing materials or heat-storing materials placed in the box 2. In the constant-temperature storage container, a latent heat first cold-storing material or heat-storing material (a) that has a solidifying and melting temperature of 0° C. or more and that is in a solidified state is placed adjacent to an article to be kept cold or warm (or an inner box 5), and a latent heat second cold-storing material or heat-storing material (b) in a molten state is placed on an outer side of the latent heat first cold-storing material or heat-storing material (a).

FIG. 2 shows a second embodiment of the constant-temperature storage container of the present invention. The constant-temperature storage container 1B of the second embodiment is a container suited for environments where an external temperature of the container is higher than a predetermined container management temperature. The constant-temperature storage container 1B of the second embodiment further includes, in addition to the first cold-storing material or heat-storing material (a) and the second cold-storing material or heat-storing material (b), a third cold-storing material or heat-storing material (c) in a lower temperature state than the second cold-storing material or heat-storing material (b) on an outer side of the second cold-storing material or heat-storing material (b).

The structure of the box 2 is not specifically limited, but it is preferable that the box 2 includes a box body 3 that is composed of a heat-insulating material and that has a bottom part, that the box body 3 is attached with a cover 4 that is also composed of a heat-insulating material, and that an opening of the box body 3 can be closed and opened with the cover 4. An interdigitation between the box body 3 and the cover 4 having a fitting structure can provide the container with better heat-insulating properties.

The material and the composition of the box 2 are not specifically limited, but the box 2 is preferably composed of a heat-insulating material, for example, a molded article of a foamed synthetic resin. The material may be a foamed synthetic resin laminated with an aluminum foil or resin film in order to increase the heat-insulating properties. As a substrate resin of the foamed synthetic resin, for example, polystyrene resins such as polystyrene and polyolefin resins such as polyethylene or polypropylene may be used. Among them, a polystyrene resin, especially, generally used polystyrene is suitably used from the viewpoints of price and strength.

An article to be kept cold or warm may be stored in the box 2 without treatment or may be wrapped with a synthetic resin sheet, a film, or the like to be stored in the box 2. The box 2 may further include an inner box 5 that holds the inner shape and that stores the article to be kept cold or warm. The inner box 5 may have a cover that is not shown in the schematic view for closing and opening an opening of the inner box 5. The inner box 5 does not necessarily have the cover when the warm or cold insulation function is not affected. The inner box 5 preferably has the heat-insulating properties as with the outer box 2 because such an inner box can elongate the thermal management time.

In order to improve the heat-insulating properties, for example, as a constant-temperature storage container 1C shown in FIG. 3, a heat insulating material such as a foam resin plate 6 may be interposed between the cold-storing materials or heat-storing materials (a), (b), and (c). A substrate resin of the foam resin plate 6 may be the same as that of the outer box 2, and, for example, a polystyrene resin is used.

The first cold-storing material or heat-storing material (a) and the second cold-storing material or heat-storing material (b) may have the same solidifying and melting temperature or different solidifying and melting temperatures from each other as long as the first cold-storing material or heat-storing material (a) is in a solidified state, the second cold-storing material or heat-storing material (b) is in a molten state, and the phase states are different from each other. In the present invention, the arrangement of stacked two or more kinds of latent heat cold-storing materials or heat-storing materials in different phase states as above can achieve thermal management over long periods of time.

In the present invention, in the condition where an outside air temperature is lower than a predetermined temperature range, as shown in FIG. 1, as the first cold-storing material or heat-storing material (a) adjacent to an article to be kept cold or warm (or the inner box 5), a first cold-storing material or heat-storing material (a) in a solidified state is placed, and as the second cold-storing material or heat-storing material (b) to be placed on the outer side of the first cold-storing material or heat-storing material, a second cold-storing material or heat-storing material (b) in a molten state is placed. In this case, firstly, the second cold-storing material or heat-storing material (b) is cooled due to the outside air temperature to have a reduced temperature, and the phase is transformed from the molten state (liquid) to the solidified state (solid) to discharge thermal energy. Hence, the first cold-storing material or heat-storing material (a) is suppressed to be exposed to an outside air having a low temperature, and the first cold-storing material or heat-storing material (a) is not excessively cooled. Therefore, the first cold-storing material or heat-storing material (a) can maintain the temperature in the container 1A in a predetermined temperature range more than 0° C. over long periods of time.

In contrast, in the condition where an outside air temperature is higher than a predetermined temperature range, as shown in FIG. 2, a third cold-storing material or heat-storing material (c) in a lower temperature state than the second cold-storing material or heat-storing material (b) is further stacked and placed on the outer side of the second cold-storing material or heat-storing material (b). Hence, during the third cold-storing material or heat-storing material (c) is heated due to the outside air temperature to absorb thermal energy, the second cold-storing material or heat-storing material (b) is suppressed to be heated due to the outside air having a high temperature. Moreover, the second cold-storing material or heat-storing material (b) is cooled by the third cold-storing material or heat-storing material (c) to have a reduced temperature, and the phase is transformed from the molten state (liquid) to the solidified state (solid) to discharge the thermal energy. Therefore, the first cold-storing material or heat-storing material (a) is not excessively cooled by the third cold-storing material or heat-storing material (c), and the first cold-storing material or heat-storing material (a) can maintain the temperature in the container 1B in a predetermined temperature range more than 0° C. over long periods of time.

In the present invention, the arrangement of a cold-storing material or heat-storing material having a solidifying and melting temperature of more than 0° C. as at least the first cold-storing material or heat-storing material (a) can achieve accurate thermal management in an arbitrary temperature range more than 0° C. However, the management temperature of the container is preferably 1 to 30° C. and more preferably 2 to 8° C. from the viewpoint of characteristics of articles under thermal management, such as a pharmaceutical product and a food.

Here, the container management temperature means an intermediate temperature of the lower limit temperature and the upper limit temperature in a predetermined temperature range (required thermal management range) of an article to be kept cold or warm, and, for example, when the lower limit temperature is 2° C. and the upper limit temperature is 8° C., the container management temperature is (2+8)/2=5° C.

In the present invention, when the container management temperature is A (° C.), the first cold-storing material or heat-storing material (a) that has a solidifying and melting temperature of (A−3)° C. to (A+3)° C. and that is in a solidified state and the second cold-storing material or heat-storing material (b) that has a solidifying and melting temperature of (A−3)° C. to (A+3)° C. and that is in a molten state are preferably used, and the cold-storing materials or heat-storing materials (a) and (b) each having a solidifying and melting temperature of A (° C.) is more preferably used. The use of the cold-storing materials or heat-storing materials (a) and (b) in this combination can elongate the accurate thermal management time, and it can increase the effect especially when the outside air temperature is lower than the container management temperature A (° C.).

Meanwhile, when the outside air temperature is higher than the container management temperature A (° C.), the third cold-storing material or heat-storing material (c) preferably has a solidifying and melting temperature of (A−15)° C. to A (° C.) and more preferably (A−10)° C. to (A−5)° C. The use of the cold-storing materials or heat-storing materials (a) to (c) in this combination can elongate the accurate thermal management time, and it can increase the effect especially when the outside air temperature is higher than the container management temperature A (° C.).

Furthermore, the heat-storing material (a) that has a solidifying and melting temperature of 2 to 8° C. and that is in a solidified state (solid) and the heat-storing material (b) that has a solidifying and melting temperature of 2 to 8° C. and that is in a molten state (liquid) are specifically preferably used. The use of the cold-storing materials or heat-storing materials (a) and (b) in this combination can elongate the thermal management time at a container management temperature of 5° C.±3° C. where the thermal management is particularly difficult, and it can increase the effect especially when the outside air temperature is lower than 5° C.±3° C. that is the container management temperature.

When the outside air temperature is higher than the container management temperature, a cold-storing material that mainly contains water and that has a solidifying and melting temperature of −5 to 0° C. is specifically preferably used as the third cold-storing material or heat-storing material (c). The use of the cold-storing materials or heat-storing materials (a) to (c) in this combination can elongate the thermal management time at a container management temperature of 5° C.±3° C. where the thermal management is particularly difficult, and it can increase the effect especially when the outside air temperature is higher than 5° C.±3° C. that is the container management temperature.

Examples of the material of the latent heat first and second cold-storing materials or heat-storing materials (a) and (b) used in the present invention include, but are not necessarily limited to, inorganic hydrate salt heat-storing materials such as sodium sulfate decahydrate, sodium acetate trihydrate, potassium chloride hexahydrate, and a quaternary ammonium salt hydrate; organic compound heat-storing materials such as paraffin wax, a saturated fatty acid having a C₆ to C₁₈ carbon chain, an unsaturated fatty acid having a C₆ to C₁₈ carbon chain, and a polyalkylene glycol; and a heat-storing material composition that is described in JP-A No. 2006-96898 and that contains an aqueous solution of at least one salt being insoluble in a polyalkylene glycol and soluble in water and a polyalkylene glycol. Among them, the heat-storing material composition described in JP-A No. 2006-96898 is preferred because it is inexpensive and safe as well as excellent in temperature control and thermal management time and is specifically preferred for air transportation.

Examples of the material of the third cold-storing material or heat-storing material (c) include, but are not necessarily limited to, cold-storing materials mainly containing water, such as an aqueous potassium hydrogen carbonate solution, an aqueous potassium chloride solution, an aqueous ammonium chloride solution, and an aqueous sodium chloride solution; and cold-storing materials containing water and a super absorbent polymer. Among them, a cold-storing material that mainly contains water and that has a solidifying and melting temperature of −5 to 0° C. is preferred because it is inexpensive and safe.

In the embodiments shown in FIGS. 1, 2, and 3, the first to third cold-storing materials or heat-storing materials (a), (b), and (c) are stacked on the upper and lower faces alone in the box 2, but the cold-storing materials or heat-storing materials (a) to (c) may be placed on any face in the box 2. Namely, the cold-storing materials or heat-storing materials (a), (b), and (c) can be placed on any face as long as the stacking order follows the invention. For example, the cold-storing materials or heat-storing materials (a), (b), and (c) may be placed on the lateral faces alone of the box 1 in this order, and the cold-storing materials or heat-storing materials (a), (b), and (c) may be stacked and placed on all of the upper, lower, and lateral faces in this order. Generally, when the difference is larger between the container management temperature and the outside air temperature, the cold-storing materials or heat-storing materials are preferably placed on more faces.

EXAMPLES

Hereinafter, the present invention will be described with reference to examples, but the invention is not intended to be limited to these examples.

Example 1

On inner faces of an expanded polystyrene heat-insulating container 1 (an external dimension of 620 mm×420 mm×470 mm and an inner dimension of 500 mm×300 mm×350 mm), cold-storing materials or heat-storing materials having the below structure were placed as shown in FIG. 2, and roughly in the center of the inner space, an expanded polystyrene inner box 5 (an external dimension of 430 mm×297 mm×165 mm and an inner dimension of 390 mm×255 mm×125 mm) was stored to prepare a package for measurement.

Onto each of the upper and lower faces of the inner box 5, four pieces of 500 g of first heat-storing material (a) [Patthermo P-5 that was manufactured by Tamai Kasei Corporation and that was solidified in an environment at 4° C.] that was in a solidified (solid) state in an environment at 4° C. and that had a solidifying and melting temperature of 5° C. were placed, and on each lateral face, two pieces of the same heat-storing material (a) were also placed. On each of the upper and lower faces of the heat-storing material (a), two pieces of 200 g of second heat-storing material (b) [Patthermo P-5 that was manufactured by Tamai Kasei Corporation and that was molten at a room temperature of around 20° C.] that was in a molten (liquid) state at a room temperature of around 20° C. and that had a solidifying and melting temperature of 5° C. were placed. On each of the upper and lower faces of the heat-storing material (b), eight pieces of 500 g of third cold-storing material (c) [Cold Ice (a solidifying and melting temperature=0° C.) that was manufactured by Tamai Kasei Corporation and that was completely frozen] that was in a completely frozen (solid) state in an environment of 0° C. or less and that mainly contained water were further placed.

Here, 500 g of the first heat-storing material (a) was filled in a polyethylene blow molded container having a size of 140 mm×220 mm×25 mm to be used. For 200 g of the second heat-storing material (b), a bag was prepared from expanded polyethylene having a thickness of 1 mm; the bag was laminated with polyethylene and polyamide to prepare a bag having a thickness of 0.9 mm; and the heat-storing material was filled in the bag having a size of 230 mm×290 mm×7 mm. While, 500 g of the third cold-storing material (c) was filled in a polyethylene blow molded container having a size of 140 mm×220 mm×25 mm.

The package for measurement as above was left in a constant temperature chamber controlled at a temperature of 35° C., and the temperature in the inner box 5 was determined using a data logger [RTR-52 manufactured by T&D Corporation]. The result is shown in FIG. 4. In the graph in FIG. 4, the vertical axis represents temperature and the horizontal axis represents elapsed time. As shown in the graph in FIG. 4, the temperature in the inner box 5 could be maintained within 5° C.±3° C. over 40 hours or more.

Example 2

A package for measurement was obtained to have the same configuration of cold-storing materials or heat-storing materials as that in Example 1.

The package for measurement was left in a constant temperature chamber controlled at a temperature of 15° C., and the temperature in the inner box 5 was determined using a data logger. The result is shown in FIG. 5. In the graph in FIG. 5, the vertical axis represents temperature and the horizontal axis represents elapsed time. As shown in the graph in FIG. 5, the temperature in the inner box 5 could be maintained within 5° C.±3° C. over 96 hours or more while the temperature was not lowered to 2° C. or less.

Example 3

A package for measurement was obtained in the same manner as in Example 1 except that the configuration of cold-storing materials or heat-storing materials was changed as below.

Onto each of the upper and lower faces of the inner box, four pieces of 500 g of heat-storing material (a) that was in a solidified (solid) state in an environment of 4° C. and that had a solidifying and melting temperature of 5° C. were placed, and onto each lateral face, two pieces of the same heat-storing material (a) were also placed. Onto each of the upper and lower faces, two pieces of 200 g of heat-storing material (b) that was in a molten (liquid) state at a room temperature of around 20° C. and that had a solidifying and melting temperature of 5° C. were placed. On the upper face, 12 pieces of 500 g of cold-storing material (c) that was in a completely frozen (solid) state in an environment of 0° C. or less and that mainly contained water were further placed, and on the lower face, eight pieces of the same cold-storing material (c) were also placed.

The package for measurement was left in a constant temperature chamber controlled at a temperature of 35° C., and the temperature in the inner box 5 was determined using a data logger. The result is shown in FIG. 6. In the graph in FIG. 6, the vertical axis represents temperature and the horizontal axis represents elapsed time. As shown in the graph in FIG. 6, the temperature in the inner box 5 could be maintained within 5±3° C. over 72 hours or more.

Comparative Example 1

A package for measurement was obtained in the same manner as in Example 1 except that the configuration of cold-storing materials or heat-storing materials was changed as below.

On each of the upper and lower faces of the inner box 5, four pieces of 500 g of cold-storing material (d, a solidifying and melting temperature=0° C.) that was controlled in an environment of 4° C. and that mainly contained water were placed, and on each of the right and left lateral faces, two pieces of the same cold-storing material (d) were also placed. Onto each of the upper and lower faces, eight pieces of 500 g of cold-storing material (c, a solidifying and melting temperature=0° C.) that was in a completely frozen (solid) state in an environment of 0° C. or less and that mainly contained water were placed.

The package for measurement was left in a constant temperature chamber controlled at a temperature of 35° C., and the temperature in the inner box 5 was determined using a data logger. The result is shown in FIG. 7. In the graph in FIG. 7, the vertical axis represents temperature and the horizontal axis represents elapsed time. As shown in the graph in FIG. 7, the temperature in the inner box 5 was once reduced to 2° C. or less.

Example 4

A package for measurement was obtained in the same manner as in Example 1 except that the configuration of cold-storing materials or heat-storing materials was changed as shown in FIG. 1.

On each of the upper and lower faces of the inner box, eight pieces of 500 g of heat-storing material (a) that was in a solidified (solid) state in an environment of 4° C. and that had a solidifying and melting temperature of 5° C. were placed, and on each lateral face, two pieces of the same heat-storing material (a) were also placed. On each of the upper and lower faces, 12 pieces of 500 g of heat-storing material (b) that was in a molten (liquid) state at a room temperature of around 20° C. and that had a solidifying and melting temperature of 5° C. were placed.

The package for measurement was left in a constant temperature chamber controlled at a temperature of −10° C., and the temperature in the inner box 5 was determined using a data logger. The result is shown in FIG. 8. In the graph in FIG. 8, the vertical axis represents temperature and the horizontal axis represents elapsed time. As shown in the graph in FIG. 8, the temperature in the inner box 5 could be maintained within 5±3° C. over 66 hours or more.

Here, 500 g of the heat-storing material (a) was filled in a polyethylene blow molded container having a size of 140 mm×220 mm×25 mm to be used. While, 500 g of the heat-storing material (b) was filled in a polyethylene blow molded container having a size of 140 mm×220 mm×25 mm to be used.

Example 5

A package for measurement was obtained in the same manner as in Example 1 except that the configuration of cold-storing materials or heat-storing materials was changed to the configuration shown in FIG. 3.

On each of the upper and lower faces of the inner box 5, four pieces of 500 g of heat-storing material (a) that was in a solidified (solid) state in an environment of 4° C. and that had a solidifying and melting temperature of 5° C. were placed, and on each lateral face, two pieces of the same heat-storing material (a) were also placed. On each of the upper and lower faces of the heat-storing materials (a), an expanded plastic plate 6 [made from expanded polystyrene] having a thickness of 10 mm was placed. On each of the upper and lower faces of the expanded plastic plate 6, eight pieces of 500 g of heat-storing material (b) that was in a molten (liquid) state at a room temperature of around 20° C. and that had a solidifying and melting temperature of 5° C. were further placed.

The package for measurement was left in a constant temperature chamber controlled at a temperature of −10° C., and the temperature in the inner box 5 was determined using a data logger. The result is shown in FIG. 9. In the graph in FIG. 9, the vertical axis represents temperature and the horizontal axis represents elapsed time. As shown in the graph in FIG. 9, the temperature in the inner box 5 could be maintained within 5° C.±3° C. over 40 hours or more in a temperature condition at −10° C.

Comparative Example 2

A package for measurement was obtained in the same manner as in Example 1 except that the configuration of cold-storing materials or heat-storing materials was changed as shown below.

On the upper face of the inner box 5, 12 pieces of 500 g of heat-storing material (a) that was in a solidified (solid) state in an environment of 4° C. and that had a solidifying and melting temperature of 5° C. were placed, while on the lower face of the inner box 5, 16 pieces of the same heat-storing material (a) were placed, and on each lateral face, two pieces of the same heat-storing material (a) were also placed.

The package for measurement was left in a constant temperature chamber controlled at a temperature of −10° C., and the temperature in the inner box 5 was determined using a data logger. The result is shown in FIG. 10. In the graph in FIG. 10, the vertical axis represents temperature and the horizontal axis represents elapsed time. As shown in the graph in FIG. 10, the temperature in the inner box 5 could be maintained within 5±3° C. for only 30 hours.

REFERENCE SIGNS LIST

• • a First heat-storing material being in a solidified (solid) state at 4° C. and having a solidifying and melting temperature of 5° C.
  • b Second heat-storing material being in a molten (liquid) state at around 20° C. and having a solidifying and melting temperature of 5° C.
  • c Third cold-storing material mainly containing water and being in a completely frozen (solid) state in an environment of 0° C. or less
  • 1A, 1B, 1C Constant-temperature storage container
  • 2 Expanded plastic heat-insulating container (outer box)
  • 3 Box body
  • 4 Cover
  • 5 Expanded plastic container (inner box) for holding inner shape
  • 6 Expanded plastic plate having a thickness of 10 mm

Claims

1. A constant-temperature storage container comprising:

a heat-insulating box; and

two or more kinds of cold-storing materials or heat-storing materials placed in the heat-insulating box;

a latent heat first cold-storing material or heat-storing material (a) in a solidified state being placed adjacent to an article to be kept cold or warm;

a latent heat second cold-storing material or heat-storing material (b) in a molten state being placed on an outer side of the first cold-storing material or heat-storing material (a); and

the first cold-storing material or heat-storing material (a) having a solidifying and melting temperature of more than 0° C.

2. The constant-temperature storage container according to claim 1, the container further comprising a third cold-storing material or heat-storing material (c), the third cold-storing material or heat-storing material (c) being placed on an outer side of the second cold-storing material or heat-storing material (b) and being in a lower temperature state than the second cold-storing material or heat-storing material (b).

3. The constant-temperature storage container according to claim 1 or 2, wherein a container management temperature A (° C.) is 1 to 30° C.

4. The constant-temperature storage container according to claim 1 or 2, wherein the first cold-storing material or heat-storing material (a) and the second cold-storing material or heat-storing material (b) have a solidifying and melting temperature of (A−3)° C. to (A+3)° C. where the container management temperature is A (° C.).

5. The constant-temperature storage container according to claim 2, wherein the third cold-storing material or heat-storing material (c) has a solidifying and melting temperature of (A−10)° C. to (A−5)° C. where the container management temperature is A (° C.).

6. The constant-temperature storage container according to claim 1 or 2, wherein the first cold-storing material or heat-storing material (a) and the second cold-storing material or heat-storing material (b) have a solidifying and melting temperature of 2° C. to 8° C.

7. The constant-temperature storage container according to claim 2, wherein the third cold-storing material or heat-storing material (c) has a solidifying and melting temperature of −5 to 0° C.

8. The constant-temperature storage container according to claim 1 or 2, wherein at least one of the first cold-storing material or heat-storing material (a) and the second cold-storing material or heat-storing material (b) is composed of a heat-storing material composition containing an aqueous solution of at least one salt, the salt being insoluble in a polyalkylene glycol and soluble in water, and a polyalkylene glycol.

9. The constant-temperature storage container according to claim 2, wherein the third cold-storing material or heat-storing material (c) is a cold-storing material mainly containing water.

10. The constant-temperature storage container according to claim 1 or 2, wherein the article to be kept cold or warm is stored in a heat-insulating inner box.

11. An article transportation method comprising: transporting an article to be kept cold or warm stored in the constant-temperature storage container according to claim 1 where an outside air temperature of the container is lower than a container management temperature A (° C.).

12. An article transportation method comprising: transporting an article to be kept cold or warm stored in the constant-temperature storage container according to claim 2 where an outside air temperature of the container is higher than a container management temperature A (° C.).