JP2005274209A - Temperature control medium - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a highly-safe temperature control medium capable of displaying simply and irreversibly whether an article is disposed to a temperature exceeding the upper limit of a prescribed control temperature or not. <P>SOLUTION: Emulsified liquid 2 including water, oil and fat, lecithin and alcohol is filled in a container 1, and the emulsified liquid 2 is prepared so as to generate phase separation and discoloration when its temperature is raised over the upper limit of the control temperature. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a temperature management medium that can be easily placed in an atmosphere of a freezing or refrigeration temperature, and thereafter can easily confirm a temperature history of whether or not it has been exposed to a higher temperature atmosphere. For example, it is suitably used for determining whether or not the storage temperature of the luggage has become a high temperature unsuitable for freezing / refrigeration during transportation of the frozen / refrigerated luggage.

  In recent years, the number of packages delivered in a frozen or refrigerated state has further increased, and delivery means such as courier services for transporting these packages while keeping them at a predetermined low temperature to a delivery destination are becoming widespread. In such delivery means, for example, when loading a package from a refrigeration / refrigeration facility of the collection source to a delivery vehicle, when loading packages between delivery vehicles, or taking out a package from a delivery vehicle and delivering it to a delivery destination, Luggage that should be kept refrigerated must be exposed to high temperature and room temperature atmospheres under direct sunlight.

  In addition, it is required that packages that have been delivered to a delivery destination while being kept in a frozen / refrigerated state after production are maintained in a frozen / refrigerated state. For example, if the contents of the baggage are food or pharmaceuticals, the contents may be altered or germs may be propagated, and the original quality may be impaired. In extreme cases, food poisoning or medical accidents may be induced. Absent. What requires such temperature control includes various chemicals used in chemical relations and photographic relations in addition to foods and pharmaceuticals.

As a method for easily confirming whether or not the temperature management is normally performed, the following method has been proposed.
(1) Storage temperature obtained by filling a sealed container with an emulsion obtained by emulsifying one or more of C7-15 higher alcohols in which a fat-soluble dye is dissolved with a nonionic surfactant and water. An indicator for management is disclosed (Patent Document 1: Green Cross). According to such a configuration, under normal temperature conditions, the emulsified liquid has an appearance that suppresses the color tone of the pigment and exhibits an opaque milky white color. When the temperature is lower than the temperature at which the emulsion freezes, once all components are frozen as they are and when thawed again, coarsened emulsified particles float up, and oil droplets or oil layers with a dark color tone float to the upper layer. It is separated into an aqueous layer and an oil droplet or oil layer. Therefore, it is possible to call attention at the time of use because the article in the package including the indicator in which such a change is recognized may be deteriorated.

(2) A polyolefin non-woven fabric impregnated with agar gel, and a non-woven polyolefin non-woven fabric as necessary, are bonded between the polyolefin film printed with white oil-based ink containing a water-soluble dye and a polyolefin film. A frozen food temperature display sheet characterized by the structure obtained is disclosed (Patent Document 2: Toyo Ink). By adopting this structure, before the freezing operation, the water-soluble dye is contained in the white oil-based ink and does not develop color, but once frozen, the temperature of the content rises to the temperature at which it is thawed, and the nonwoven fabric By the water leached through the fine holes, the water-soluble dye is dissolved and the white oil-based ink printing surface is colored, and the temperature change of the article to which the temperature display sheet is attached can be instructed.

(3) A first label sheet provided with a pressure-sensitive adhesive layer having an organic chelate color former on one side of a base sheet, and a metal compound capable of developing color on one side of another base sheet by reacting with the organic chelate color former. A first label comprising: a second label sheet provided with a pressure-sensitive adhesive layer; and a porous sheet disposed between the pressure-sensitive adhesive layer of the first label sheet and the pressure-sensitive adhesive layer of the second label sheet. A temperature control label is disclosed, wherein a temperature control agent is contained in at least one of the pressure-sensitive adhesive layer of the sheet for use, the pressure-sensitive adhesive layer of the sheet for the second label, and the porous sheet (Patent Document 3: Lintec). According to such a configuration, the temperature control agent flows when the desired temperature is reached, and the organic chelate color former or the metal compound is moved through the porous sheet and brought into contact with each other and reacted to react with each other. By detecting the color development, it is possible to detect a temperature history as to whether or not the storage temperature of the article to which the temperature management label is attached has become equal to or higher than a predetermined temperature.

The conventional method described above has the following problems.
First, since nonionic surfactants that have been known to be environmental hormones in recent years are used, it is difficult to ensure their safety when used on foods and pharmaceuticals. . Also, if it is ingested by the body due to skin contact or accidental ingestion, it is not good because it may harm your health.
Secondly, since higher alcohol is used, if it is accidentally leaked, a bad odor is generated.
Thirdly, in the method in which the organic chelate color former or the metal compound is moved through the porous sheet and brought into contact with each other and reacted to cause irreversible color development, the solid porous sheet is an essential component, and therefore an external force is required. When it is added, there is a risk that the structure will be damaged, and care should be taken when affixing to an article being conveyed. Moreover, since it is necessary to bond together before use, the freedom of handling is narrow.

As a result of diligent research to solve the above-mentioned problems, the present inventors have frozen an emulsion composed of a lipid mixture containing water, fats and oils and phospholipids, and emulsification occurs when the thawing temperature is reached in the process of raising the temperature to room temperature. It was found that it was destroyed and phase-separated to change its color to transparent, and a temperature control medium to which this fact was applied was applied for a patent (Patent Document 4).
JP 57-37227 A JP 7-49656 A JP-A-7-286914 Japanese Patent Application No. 2003-428299

The emulsion containing water, fats and oils and phospholipids is highly safe and has suitable characteristics as an inexpensive temperature control medium. As a result of further investigation, the resulting emulsion has a thawing temperature. Since it is relatively high, it has been found that it is difficult to use in applications that require a temperature rise history at a lower temperature.
The present invention has been made in view of the above circumstances, and whether or not the storage temperature has exceeded the upper limit of the management temperature during freezing and refrigeration storage of articles for which the upper limit of the management temperature needs to be set relatively low. A temperature management medium with a structure that can detect such a temperature rise history and that is safe and has little influence on the human body even when it adheres to the skin or accidentally swallows. The purpose is to provide.

  The temperature management medium according to the present invention is filled with an emulsion containing water, fats and oils, an amphoteric surfactant, and alcohol in a container, and this emulsion undergoes phase separation when the temperature rises above the upper limit of the management temperature. It is characterized by being prepared so as to change color.

  The emulsified liquid of the present invention containing water, fats and oils, amphoteric surfactants and alcohol is frozen and placed in the management temperature range, and keeps milky white when the temperature of the article is monitored (monitored state). However, when the temperature of the system exceeds the upper limit of the control temperature for some reason, phase separation occurs upon thawing and the color changes to transparent. Once the color is changed, it does not return to the original milky white color even if it is left at room temperature or frozen again. Therefore, the temperature management medium of the present invention can confirm the temperature rise history of the temperature management medium, and thus the system in which the temperature management medium is installed, by examining the presence or absence of discoloration of the emulsion in the container. In addition, the emulsion of the present invention can further reduce the phase separation temperature, and the upper limit of the management temperature is set to be relatively low, compared with the emulsion composed of water, fats and oils, and phospholipids that do not contain alcohol. It turned out that it can be used suitably also for freezing and refrigeration storage of goods. It was also found that the temperature at which the hue changes from a milky white state to a transparent state during temperature rise can be adjusted more precisely. The emulsion used for the temperature control medium of the present invention can be either oil / water type or water / oil type.

  The fats and oils used in the present invention are generally triacylglycerols, and those having various melting points and difficulty in emulsification are known. These can be used in the present invention as single components or composite components. Further, for example, a free higher fatty acid such as oleic acid may be contained. For normal purposes, it is preferable to use an oil having a melting point of around 0 ° C. or lower. In particular, the oil and fat used in the present invention is preferably an edible oil from the viewpoint of safety.

  The alcohol used in the present invention is a hydrocarbon compound having one or more alcoholic hydroxyl groups in the molecule, and either a single component or a composite component can be used in the present invention. Examples of suitable alcohols include methanol, ethanol, n-propyl alcohol, isopropyl alcohol, n-butyl alcohol, 2-butyl alcohol, isobutyl alcohol, tertiary butyl alcohol, ethylene glycol, diethylene glycol, propylene glycol, dipropylene glycol, Examples include butylene glycol and glycerin.

It is preferable that at least a part of the amphoteric surfactant is lecithin.
Since lecithin is a natural amphoteric surfactant that has been confirmed to be safe, the temperature control medium of the present invention using lecithin as the amphoteric surfactant component of the emulsion further increases the safety. From this viewpoint, it is preferable that the amphoteric surfactant used in the temperature control medium of the present invention consists entirely of lecithin. Lecithin includes those derived from soybeans and those derived from egg yolk, all of which can be used in the present invention. Examples of amphoteric surfactants that can replace all or part of lecithin include alkylbetaine compounds and alkylamine oxide compounds.

It is preferable that at least a part of the alcohol is ethanol.
Ethanol is inexpensive and easily available and has been confirmed to be safe. In addition, the emulsion containing ethanol can be used at a lower temperature than those not containing ethanol, and the discoloration temperature can be precisely controlled.

  If necessary, the emulsion may contain at least one surfactant selected from the group of anionic surfactants and nonionic surfactants. The emulsified liquid used in the present invention is basically composed of four components of water, fats and oils, amphoteric surfactant and alcohol. If necessary for the stability of emulsification and the adjustment of the discoloration temperature, a suitable shade depending on the application is used. It does not prevent the use of ionic surfactants and nonionic surfactants.

The emulsified liquid preferably adjusts the color change temperature by controlling the blending ratio of alcohol.
The discoloration temperature can also be adjusted by controlling the melting point of the fat and oil and the concentration of the amphoteric surfactant. However, in order to respond to the individual requirements for the upper limit of the control temperature, an emulsion stock solution of a basic formulation that does not contain alcohol is prepared in advance, and for each request for the upper limit of the control temperature, the blending ratio of the alcohol to be added is set. It is desirable to respond by changing. By controlling the blending ratio of alcohol, it is possible to precisely meet a wide range of color change temperature requirements.

It is preferable that the temperature management medium of the present invention is provided with display means for explicitly indicating the above-mentioned discoloration.
The temperature management medium of the present invention confirms the temperature rise history of the system in which it is placed by observing the color change of the emulsion liquid phase. However, the color change of the emulsified liquid phase is a change from milky white to transparent, and the change may not always be clearly confirmed visually. Therefore, it is preferable to provide a display means for explicitly indicating this discoloration. As an example of simple display means, for example, there is a method of placing a colored plate or a printing plate behind the emulsion. For example, when a red colored plate is placed in the back, the surface appears milky white when the system is kept at a low temperature and the emulsion is frozen, and when the control temperature is exceeded, the emulsion is phase-separated and becomes transparent. The red color is clearly recognized.

  The emulsified form of the emulsion used in the present invention may be either oil / water type or water / oil type. In general, a water / oil type with a small proportion of water is preferred. The ratio of the oil phase: water phase in the emulsion is preferably in the range of 5:95 to 95: 5, particularly in the range of 85:15 to 40:60, by weight. The addition ratio of lecithin is preferably in the range of 0.1% to 30% by weight of the oil phase, particularly in the range of 0.5% to 10% by weight.

  The material, dimensions, and shape of the container used for the temperature control medium of the present invention are not particularly limited as long as the internal emulsion can be at least partially observed. For example, a flat cylindrical or flat box-shaped transparent plastic container with one side used as an observation window and an adhesive layer on the other side is affixed to the side of a cardboard case containing articles. Suitable for use.

  The temperature management medium according to the present invention changes the color of the emulsified liquid in the container when the temperature of the system in which the temperature management medium is installed rises above the upper limit of the management temperature. As a result, the temperature rise of the system in which the temperature control medium is installed can be confirmed. In addition, once the temperature has exceeded the upper limit of the control temperature, re-emulsification will not occur even if the temperature is lowered again, so the temperature rise history is not erased. Therefore, if this temperature management medium is attached to a package, etc., the temperature history of whether or not the storage temperature of the package has become a high temperature unsuitable for freezing or refrigeration, that is, the package that should be in a low temperature state is managed in a predetermined manner. It can be easily detected whether or not the product has been stored under conditions that do not exceed the upper limit of the temperature.

  In addition, since the emulsion used in the present invention can be prepared using only edible natural materials such as edible oil, lecithin, and ethanol, it is safe from contact or accidental ingestion. Safety is ensured during handling, and it can be used with peace of mind even in the preservation field of foods, pharmaceuticals, organs and the like that require extremely high safety.

  Since the temperature management medium of the present invention can ensure safety, the temperature management medium of the present invention is not only used as a temperature rising indicator in addition to an outer box of an article requiring temperature control, but also, for example, an article (food, medicine, etc.) inside the outer box. , Organs, etc.) or in direct contact with the article and used for confirmation of temperature history. Therefore, the present invention can be applied to a wide range of fields including fields that have been difficult to use in the past. Also, since no special materials or complicated mechanisms are required for manufacturing, it can be manufactured in large quantities and at low cost, and individual packaging is not necessarily required, so that it becomes an inexpensive and highly reliable temperature management medium.

  The temperature management medium of the present invention maintains the storage temperature of the package under an appropriate refrigeration condition in the transportation of the package that is required to be delivered to the delivery destination after being manufactured under various conditions of the freezing temperature. It is possible to easily and simply determine whether the vehicle has been leaned or whether it has been exposed to an inappropriate high temperature state, and can contribute to guaranteeing the quality of the package.

Hereinafter, the present invention will be described in detail based on preferred embodiments of the present invention.
FIG. 1 is a perspective view showing an example of a temperature management medium according to the present invention. FIG. 1 (a) shows an initial state before the temperature management medium is cooled to a management temperature, and FIG. This shows a warning state when the temperature rises beyond the upper limit of the management temperature after cooling to the management temperature.

  In FIG. 1, the present temperature control medium is a transparent plastic flat cylindrical airtight container 1 filled with an emulsified liquid 2. One surface of the container 1 (upward surface in the drawing) is an observation window 3, and the bottom plate 4 on the back surface of the container facing the observation window 3 is colored red as a warning plate. An adhesive layer 5 for adhering to an article package or the like is applied to the outside of the bottom plate 4, and the surface of the adhesive layer 5 is protected by a release paper 6. As will be described in detail in the following examples, the emulsion 2 is prepared using water, fats and oils, lecithin and ethanol as components, and the discoloration temperature is adjusted by controlling the blending ratio of the alcohol. It is designed so that the emulsion breakage occurs at the upper limit of the control temperature.

  When the temperature control medium shown in FIG. 1A is peeled off the release paper 6 and attached to an article or a package (not shown) whose temperature is to be monitored and cooled within the management temperature range of the article, 2 is frozen while maintaining the emulsified state. Therefore, milky white emulsion can be seen from the observation window 3 while it is within the control temperature range. When the temperature of the system exceeds the upper limit of the management temperature for some reason, as shown in FIG. 1 (b), the emulsion 2 is defrosted and demulsified at the upper limit of the management temperature, and the emulsion 3 is transparent. The phase is irreversibly changed to the separated liquid 7. Thereby, the red color of the container bottom plate 4 can be visually recognized. That is, if the red color of the bottom plate 4 is visually recognized from the observation window 3, this is evidence that the temperature of the system has exceeded the upper limit of the management temperature at least once.

(Preparation of emulsified stock solution)
An oily phase was prepared by mixing 90% by weight of an oil and fat having a melting point of −5 ° C. (Coconard RK manufactured by Kao Corporation), 9% by weight of oleic acid, and 1% by weight of soybean lecithin. Next, while gradually adding 450 g of the oil phase to 100 g of pure water, an emulsification machine (TK Robotics manufactured by Tokushu Kika Kogyo Co., Ltd.) is used to emulsify at 10,000 rpm for 5 minutes to prepare an emulsified stock solution. did.
(Preparation of emulsion)
Emulsions A to D were prepared by adding ethanol of the amount shown in Table 1 to 50 g of the emulsified stock solution and stirring until uniform.
As a comparative example of the emulsion preparation method, emulsification was carried out in the same manner as the preparation of the emulsion stock solution while gradually adding 400 g of the oil containing 1 wt% soybean lecithin to 110 g of an aqueous solution containing 10 wt% ethanol. And could not be emulsified.
(Creation of temperature control media)
The emulsions A to D prepared as described above were filled in the containers 1 shown in FIG. 1A, respectively, and temperature control media of Examples 1 to 4 were prepared. For comparison, an emulsion stock solution not containing ethanol was filled in the container 1 to prepare a temperature control medium of a comparative example.

(performance test)
Each temperature control medium was put in a freezing room at -18 ° C to -20 ° C and allowed to stand for 4 hours. Then, each sample was taken out from the freezer compartment, and immediately after taking out, the state of the emulsion was observed from the observation window 3. The observation results are shown in Table 1 as “monitoring state”. Next, the sample taken out was naturally heated to −5 ° C., and the state of the emulsion was observed. The observation results are shown as “warning state” in Table 1.
The evaluation of the observation results was performed in the following three stages.
A state where a uniform milky white color is visible from the observation window 3.
Δ is a state where the emulsification is partially broken and the red color of the bottom plate 4 is partially recognized.
X is a state where the emulsification is broken and the red color of the bottom plate 4 is clearly visible.

  From the results shown in Table 1, each temperature control medium of Examples 1 to 4 maintains a stable emulsified state (milky white) in the monitoring state, and when the temperature is raised to −5 ° C., each of the temperature control media breaks and demulsifies. A red color of 4 was confirmed. From this result, it can be seen that each of the temperature management media of Examples 1 to 4 can be used as an indicator showing the temperature rise history of an article that requires temperature management in a low temperature region as compared with the comparative example.

Whether the temperature management medium according to the present invention uses inexpensive and readily available materials such as water, fats and oils, amphoteric surfactants, and alcohols, and whether or not the article to be temperature controlled is maintained at a relatively low management temperature. Is detected by the presence or absence of discoloration of the emulsion, so that it is small, lightweight and inexpensive, and the temperature rise history is irreversibly stored, and is effective not only for monitoring the temperature of articles during storage and transportation. For example, it can be used effectively for managing the temperature distribution in a freezer warehouse or a cooler box.
The temperature management medium according to the present invention uses edible oil, lecithin, and ethanol with high safety, so that safety is ensured even if the contents liquid leaks due to damage. Therefore, it can be advantageously used for temperature control of articles such as foods, pharmaceuticals, and organs that require high safety and reliability.

It is a perspective view which shows an example of the temperature management medium which concerns on this invention. FIG. 1A shows an initial state, and FIG. 1B shows a warning state.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Container, 2 ... Emulsified liquid, 3 ... Observation window, 4 ... Bottom plate.

Claims (5)

  The container was filled with an emulsion containing water, fats and oils, amphoteric surfactant, and alcohol, and this emulsion was prepared so as to undergo phase separation and discoloration when the temperature rose above the upper limit of the control temperature. A temperature management medium characterized by being a thing.   The temperature management medium according to claim 1, wherein at least a part of the amphoteric surfactant is lecithin.   The temperature management medium according to claim 1, wherein at least a part of the alcohol is ethanol.   The temperature control medium according to claim 1, wherein the color change temperature of the emulsified liquid is adjusted by controlling a blending ratio of the alcohol. The temperature management medium according to claim 1, further comprising display means for explicitly indicating the discoloration.

Images