JPH0650825A - Heat-sensitive indicator - Google Patents

Abstract

PURPOSE:To provide a heat-sensitive indicator which can be kept stable enough even in a normal temperature area and set simply in a prescribed monitoring state and also has a high precision. CONSTITUTION:A hermetically-sealed, flexible and transparent bag 1 is partitioned in two, a first chamber 2 and a second chamber 4, so that these chambers can be made continuous by a pressure from outside. A hot-melt substance 3 is held in the first chamber 2 and an absorption-indicating body 5 is held in the second chamber 4, while a space in the first chamber in which the hot-melt substance 3 is contained is left on the partition side in the second chamber. It is advisable that a second absorbing body having a low humidity absorbance than the absorption-indicating body 5 is held on the partition 6 side in the space of the second chamber 4 and that the absorption-indicating body 5 is in contact with the second absorbing body.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is a heat sensitive indicator which is irreversibly indicated when the temperature exceeds a set temperature.
The present invention relates to a heat-sensitive indicator used for temperature control of low temperatures necessary for frozen foods and medical fields.

[0002]

2. Description of the Related Art In recent years, many foods controlled at low temperature have been used in dietary habits. Moreover, there is a considerable difference in the storage temperature depending on the type of food that requires such low temperature control. When these products are shipped,
When the product temperature rises, the quality of the product is deteriorated, and bacteria are propagated to cause deterioration or spoilage. Therefore, quite severe conditions are required for temperature control of products.

Also in the medical field, the role of low-temperature control of special medicines, blood, specimens, etc. is very important. As for the temperature of these products, when the product temperature rises, not only the quality deteriorates, but also the product may become unusable.

Therefore, strict monitoring and recording of the temperature during such low temperature distribution are required.

A thermal indicator is commonly used to continuously monitor temperature along with frozen stock. There are already some patent applications for the heat sensitive indicator for frozen foods or frozen medical products, and the contents thereof are also known.

For example, a time-temperature integrating type monitor showing a temperature history is disclosed in JP-A-50-60262 and JP-A-51-51.
It is known from Japanese Patent No. 33432. A temperature-time monitor using a microcapsule is disclosed in Japanese Patent Laid-Open No. 61-13116.
It is known from Japanese Patent Laid-Open Publication No. 62-197486. There is also an indicator utilizing the capillary phenomenon, which is known from Japanese Patent Publication No. 3-39623.
In recent years, a mechanical mechanism has also been developed, and Japanese Patent Laid-Open No. 63-2
It is known in Japanese Patent Application Laid-Open No. 98020, Japanese Patent Application Laid-Open No. 3-183920, and the like.

[0007]

In the case of a freezer / refrigerator,
The temperature history is complicated and it is very difficult to actually monitor the storage temperature. In the case of the conventional heat sensitive indicator, when the temperature monitoring is started, the heat sensitive indicator is cooled to the temperature of the inside of the refrigerator to be monitored and then set to a predetermined monitoring state. It is difficult to select the timing to set the monitoring state, and there are many problems that must be solved in the starting mechanism itself. Also, substances that sense temperature changes in the low temperature range are
It may evaporate very easily at room temperature. For this reason, the heat sensitive indicator is difficult to store, and if it volatilizes, it naturally affects the accuracy of the heat sensitive indicator.

The present invention has been made to solve the above problems, and provides a heat sensitive indicator which can be stored in a sufficiently stable manner even at room temperature, can be easily set in a predetermined monitoring state, and has high accuracy. The purpose is to

[0009]

A heat sensitive indicator of the present invention for achieving the above object will be described with reference to FIG. 1 corresponding to an embodiment. FIG. 1 shows the situation when the thermal indicator is about to be set in the temperature monitoring state.

In the heat-sensitive indicator of the present invention, the sealed flexible transparent bag 1 can be penetrated by pressure from the outside.
The chamber 2 and the second chamber 4 are airtightly divided into two chambers, and the first chamber 2 has a heat-melting substance 3 and the second chamber 4 has a space for accommodating the heat-melting substance 3 in the first chamber. The absorption display bodies 5 are housed, respectively, leaving the partition side.

The film material constituting the flexible bag 1 is impermeable to the heat-melting substance 3 and is a heat-melting substance 3.
A transparent material that can be stored at room temperature for a long period of time is used. For example, polyvinyl chloride, polystyrene, non-axially oriented polypropylene, high density polyethylene, polyethylene terephthalate, polycarbonate, non-axially oriented nylon,
Examples thereof include acrylonitrile and cellulose acetate. Further, a composite material obtained by combining a plurality of these materials can also be given.

Examples of the heat-fusible substance 3 contained in the bag 1 include alcohols, esters, hydrocarbon compounds, ketones, and water whose freezing point is lowered.

Examples of the above alcohols include n-octyl alcohol, n-nonyl alcohol, n-decyl alcohol, n-lauryl alcohol, n-myristyl alcohol, n-cetyl alcohol, n-stearyl alcohol, olein alcohol and cyclohexanol. , Cyclopentanol, benzyl alcohol, cinnamyl alcohol, ethylene glycol, polyethylene glycol, propylene glycol, trimethylolpropane,
Examples include pentaerythrit and sorbit. Examples of the esters include amyl acetate, octyl acetate, butyl propionate, ethyl caproate, amyl caprylate,
Ethyl caprate, octyl caprate, lauryl caprate, methyl laurate, octyl laurate, lauryl laurate, methyl myristate, hexyl myristate, stearyl myristate, butyl palmitate, myristyl palmitate, methyl stearate, stearic acid Ethyl, lauryl stearate, butyl benzoate, amyl benzoate, phenyl benzoate, ethyl acetoacetate, methyl oleate, butyl acrylate, butyl oxalate, diethyl malonate, dibutyl tartrate, dimethyl sebacate, dibutyl phthalate, phthalate. Dioctyl acid, dibutyl fumarate, diethyl maleate, triethyl citrate, 1,2-hydroxystearic acid triglyceride, castor oil, dioxystearic acid methyl ester and the like. . As hydrocarbon compounds,
Aliphatic hydrocarbons such as pentadecane, tetradecane, hexadecane, 1-heptadecane, 1-octadecane,
Examples thereof include aromatic hydrocarbon compounds such as p-xylene and dodecylbenzene. Examples of the ketones include diethyl ketone, ethyl butyl ketone, methylhexyl ketone, mesityl oxide, cyclohexanone, methylcyclohexanone, acetophenone, benzophenone, acetonylacetone and diacetone alcohol. Examples of ethers include butyl ether, hexyl ether, diphenyl ether, dioxane, ethylene glycol dibutyl ether, diethylene glycol dibutyl ether, ethylene glycol diphenyl ether, and ethylene glycol monophenyl ether. The water whose freezing point is lowered is water to which an inorganic or organic freezing point depressant is added, and in that case, the freezing point depressant is sodium carbonate, ammonium hydrogen carbonate, potassium hydrogen carbonate, ammonium chloride, potassium chloride, Examples thereof include sodium chloride, magnesium chloride, calcium chloride, sodium nitrate, ammonium nitrate, urea, sodium hydrogen carbonate, sodium thiosulfate, glucose, sucrose, fructose and the like. Such freezing point depressants may be used alone or in combination.

If the heat-meltable substances 3 are appropriately mixed within a range that does not impair the object of the present invention, generally fine adjustment of the melting point becomes possible.

When the heat-fusible substance 3 is colored, the temperature abnormality may be more clearly visually recognized. As the colorant in this case, a colorant that can be dissolved in the heat-meltable substance 3 to be used is used, and it may be, for example, a dye or, if necessary, a pigment. Examples of dyes include oil-soluble dyes, direct dyes, acid dyes, basic dyes, mordant dyes, sulfur dyes,
Examples include sulfurized vat dyes, vat dyes, azoic dyes, disperse dyes, reactive dyes, and oxidation dyes. As an oil-soluble dye,
Sudan IV from Wako Pure Chemical Industries, Oil Orange 201, Oil Blue 2N, Oil Brown BB, Vali from Orient Chemical Industries
Fast Colore Red 3306, Oil Red 5B, Oil Red RR, Mitsubishi Chemical's Diaresin Blue J, Nippon Kayaku's Kayaset Red 802, and the like.

The absorption display body 5 accommodated in the bag 1 together with the heat-meltable substance 3 is formed of an absorber capable of stably absorbing and carrying the heat-meltable substance 3 in a molten state, and particularly formed in a sheet shape. It is good to have Examples of such an absorber include an absorbent sheet such as a filter paper, and specific examples thereof include a porous film, a qualitative filter paper, a quantitative filter paper, a glass fiber filter paper and a chromatography filter paper. Other examples of the absorber include pulp, cotton, non-woven fabric, silica gel, a porous inorganic sintered body, and a composite material obtained by mixing a plurality of these. As the above-mentioned porous film, there is one formed of, for example, polytetrafluoroethylene resin fiber and silica gel, which is preferable because the absorption display 5 can have very stable penetration.

In the second chamber 4, a second absorber having a lower degree of absorption than the absorption indicator 5 is accommodated on the partition 6 side, and the absorption indicator 5 is in contact with the second absorber. Good.

Examples of the material of the second absorber include glass fiber filter paper, chromatography filter paper, pulp, powder filter paper, and finely divided silica gel. The actual selection of the material is determined by the correlation with the absorption display body 5 described above,
Generally, glass fiber filter paper is preferred. When such a second absorber is stored in the second chamber 4, the first chamber 2 and the second chamber 4 are
When the heat-fusible substance 3 that penetrates the partition 6 between and receives the predetermined heat and melts, it is effectively guided to the absorption display body 5.

Such a heat-sensitive indicator is usually stored in a freezer / refrigerator and the like in association with the frozen stock and used for temperature control of the frozen stock. If the absorption indicator 5 is contaminated with the heat-fusible substance 3, it is determined that the storage situation is abnormal.

[0020]

When the above heat sensitive indicator is carried into the low temperature chamber, the heat fusible substance 3 in the flexible bag 1 is solidified at a predetermined temperature. When the first chamber 2 is pressed with a finger or mechanical force, the partition 6 is broken, and the heat-meltable substance 3 is pushed out into the second chamber 4 and comes into contact with the absorption display body 5.

If the temperature inside the low temperature chamber exceeds the freezing point of the heat-meltable substance 3, the heat-meltable substance 3 melts and exudes to the absorption display body 5 and stains the absorption display body 5. 2nd chamber 4
The width of the heat sink controls the speed at which the heat-meltable substance 3 permeates the absorption display body 5.

When the heat-fusible substance 3 is colored, the absorption display body 5 is colored, and it can be seen more clearly that the temperature has changed.

Even when the second chamber 4 is filled with the second absorber for guiding the flow of the melt, the seeping speed of the heat-meltable substance 3 to the absorption display body 5 changes.

The set temperature can be changed by changing the kind of the heat-fusible substance 3.

The heat-fusible substance 3 is contained in the sealed flexible bag 1 and the partition 6 with the second chamber 4 is airtight, so that it is kept at room temperature before being carried into the low temperature chamber. Even if it has been stored for a long time, it will not deteriorate.

[0026]

EXAMPLES Examples of the present invention will be described below. Example 1 As shown in FIG. 1, a transparent polypropylene bag 1 having a depth of 2.5 cm and a frontage of 2.0 cm is provided on a plastic plate 7 with an adhesive. The inside of the bag 1 is divided into two chambers, and the boundary is hermetically heat-sealed with the strength to easily penetrate by the external pressure. 0.75 g of the heat-meltable substance 3 in the first chamber 2 on the bottom side, and the second chamber 4 on the mouth 8 side
Each of the absorption display bodies 5 is housed with a space left on the partition side capable of accommodating the heat-meltable substance 3. The heat-meltable substance 3 is 0.02 g of brilliant blue which is a blue dye and 1 part of water.
It is an ammonium chloride aqueous solution prepared by mixing 00 g and 29.4 g of ammonium chloride, and its melting point is set below the freezing point. In the absorption indicator 5, a chromatography filter paper 526 (manufactured by Toyo Roshi Kaisha, Ltd.) has a size of 2.0 × 4.0 cm.
It is formed by being cut to the size of.

The mouth portion 8 of the bag 1 is tightly sealed with a bag film within a range of about 1/2 of the mouth portion 8 side, and a part of the absorption display member 5 is sandwiched between the contact portions to absorb moisture. Sex is suppressed. The above heat-sensitive indicator was carried into the freezer, and the heat-meltable substance 3, that is, the ammonium chloride aqueous solution was solidified. As shown in FIG. 1, the first chamber 2 was crushed with a finger in the freezer, the solidified ammonium chloride aqueous solution was pushed into the second chamber 4, and then the temperature in the freezer was raised. The blue ammonium chloride solution dissolves at -16 ° C,
It was confirmed that the chromatographic filter paper was colored.

Example 2 The same procedure as in Example 1 was repeated except that a polypropylene flexible bag 1 having a depth of 2.0 cm and a frontage of 1.5 cm was used instead of the polypropylene bag, and the ammonium chloride aqueous solution was used instead. Was used with 50.0 g of decyl alcohol. Decyl alcohol was colored with 0.02 g of oil red. 2.0 x 3.0 cm TL instead of chromatography filter paper
C sheet (manufactured by 3M Co., Ltd.) was used.

It was confirmed that the blue decyl alcohol was dissolved at −2 ° C. and the TLC sheet was colored.

In the above embodiment, the bag film is in close contact with a part of the absorption display body 5 on the mouth portion 8 side. Therefore, the time when the ambient temperature was above the melting point of the hot melt could be roughly estimated by adjusting the length of the colored portion.

[0031]

The heat sensitive indicator of the present invention can be stored in a sufficiently stable manner even at room temperature. It is easy and accurate to set the monitor condition. By coloring the heat-fusible substance, it is possible to visually check whether the environmental temperature is higher than the set temperature, and the temperature control becomes easier.

[Brief description of drawings]

FIG. 1 is a sectional view of a heat sensitive indicator to which the present invention is applied.

[Explanation of symbols]

1 is a bag, 2 is a first chamber, 3 is a heat-meltable substance, 4 is a second chamber,
5 is an absorption display, 6 is a partition, 7 is a plastic plate, 8
Is the mouth.

Claims (2)

[Claims] 1. A hermetically-sealed flexible transparent bag is hermetically divided into two chambers, a first chamber and a second chamber, which can be penetrated by pressure from the outside thereof, and the first chamber is heat-melted. A heat-sensitive indicator characterized in that the absorption display body is housed in each of the first and second chambers, leaving a space on the partition side capable of accommodating the heat-meltable substance of the first chamber. 2. A second absorbent body having a lower moisture absorption than the absorbent display body is housed on the partition side in the void of the second chamber, and the absorbent display body is in contact with the second absorbent body. The heat-sensitive indicator according to claim 1.