JP3176440B2 - Thermal indicator - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat-sensitive indicator which is irreversibly indicated when the temperature exceeds a set temperature,
The present invention relates to a thermal indicator used for controlling a low temperature required for frozen foods and the medical field.

[0002]

2. Description of the Related Art In recent years, a large number of foods controlled at a low temperature have been used in eating habits. In addition, foods requiring such low-temperature management have a considerable difference in storage temperature depending on the type. When these products are shipped,
When the temperature of the product rises, the quality of the product is degraded, and bacteria are proliferated, causing deterioration and decay. Therefore, quite strict conditions are required for product temperature control.

[0003] In the medical field, the role of low-temperature management of special drugs, blood, specimens and the like plays an extremely important role. These products may not only deteriorate in quality as the product temperature rises, but may also become unbearable for use of the products.

[0004] Therefore, strict monitoring and recording of the temperature at the time of low-temperature distribution are required. In order to continuously monitor the temperature together with the frozen storage, a thermal indicator is generally used. There have already been several patent applications for thermal indicators for frozen foods or frozen medical products, the contents of which are known.

[0005] For example, a time-temperature integrating type monitor showing a temperature history is disclosed in Japanese Patent Application Laid-Open Nos.
It is known from JP-A-33432. A temperature-time monitor using microcapsules is disclosed in JP-A-61-131.
No. 16 or JP-A-62-197486. There is also an indicator utilizing the capillary phenomenon, which is known in JP-A-59-164929 and JP-A-59-175172.

[0006]

SUMMARY OF THE INVENTION In the case of a refrigerator / refrigerator,
The temperature history is complicated and it is very difficult to actually monitor the storage temperature. In the case of the conventional thermal indicator, when starting the temperature monitoring, the thermal indicator is cooled down to the temperature inside the refrigerator to be monitored, and then set to a predetermined monitoring state. It is difficult to select the timing for setting the monitoring state, and there are many problems that need to be solved for the starting mechanism itself. In addition, substances that sense temperature changes in the low temperature range
At room temperature, it may be very volatile. Volatilization naturally affects the accuracy of the thermal indicator. Storage of the thermal indicator itself is also difficult. In addition, in the case of the conventional thermal indicator, there is a problem that the presence or absence of the reaction is unclear.

The present invention has been made in order to solve the above-mentioned problems, and can be stored sufficiently stably even at a normal temperature range, a mechanism for setting a predetermined temperature monitoring state is simple, and there is very little reaction to heat. It is an object of the present invention to provide a clear and accurate thermal indicator.

[0008]

A thermal indicator according to 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 being set to the temperature monitoring state.

In FIG. 1, a colored heat-meltable substance 3 is accommodated in a concave portion inside a projection 1 formed by a cap which can be depressed by an external pressure such as a finger pressure. The opening of the concave portion is closed with a thin lid 9 that can be broken by the above-mentioned pressure. An absorber 7 that can penetrate the melt of the colored heat-fusible substance 3 is arranged outside the concave portion via the thin lid 9. On the surface of the absorber 7, a pattern 10 is drawn with ink that repels a melt of the colored heat-fusible substance 3.

The colored heat-fusible substance 3 is accommodated in a recess inside the projection 1. A void is formed by a hollow ring 11 outside the recess opening via the thin lid 9. The carrier 5 is arranged on the absorber 7 inside the hollow ring 11.

The colored heat-fusible substance 3 may be carried on a carrier 5 and housed in a recess inside the projection 1.

The carrier 5 has a function of controlling the permeation rate of the colored heat-fusible substance 3, whereby stable permeation in the absorber 7 can be obtained. Therefore, the carrier 5 may be disposed on the absorber 7 inside the hollow ring 11 without being enclosed in the concave portion inside the projection 1. It is preferable that the carrier 5 absorbs the colored heat-fusible substance 3 well and has a slightly weaker absorbing power than the absorber 7, and examples thereof include glass fiber filter paper, chromatography filter paper, pulp, powder filter paper, and fine silica gel. Can be Of these, glass fiber filter paper is particularly preferred.

The absorber 7 carries the colored heat-fusible substance 3,
It is preferable that a stable permeation can be obtained, for example, porous film, qualitative filter paper, quantitative filter paper, glass fiber filter paper, filter paper such as filter paper for chromatography, pulp, cotton, nonwoven fabric, silica gel, porous inorganic sintered body, And a composite obtained by mixing a plurality of these.

The ink of the pattern 10 drawn on the absorber 7 is used after being imparted with water repellency or oil repellency which is insoluble in the colored heat-fusible substance 3 and repels the colored heat-fusible substance 3 in a molten state. When the colored heat-fusible substance 3 is lipophilic, an oil-repellent ink is selected. In the case of hydrophilicity, a water-repellent ink is selected. The ink usually contains a colorant and a binder,
Where appropriate, silicon or the like is included. It is particularly preferable that the colorant has a color tone that can be dissolved in a binder to be mixed and that makes the colored state of the pattern 10 stand out when arranged with the colored heat-fusible substance 3. Examples of dyes include oil-soluble dyes, direct dyes, acid dyes, basic dyes, mordant dyes, sulfur dyes, sulfur vat dyes, vat dyes, azoic dyes, disperse dyes, reactive dyes,
Oxidation dyes and the like. As the binder, rosin or rosin derivative, petroleum resin, phenol resin, xylene resin, alkyd resin, coumarone resin, acrylic resin, epoxy resin, ketone resin, styrene-maleic acid resin, cellulose resin, polyvinyl butyral resin,
Examples thereof include vinyl chloride-vinyl acetate copolymer, ethylene-vinyl acetate copolymer, polyamide, and polyurethane. These may be used alone or in combination. Silicon or the like is preferably added at a rate of several percent. When silicon or the like is added in this manner, water repellency or oil repellency is appropriately imparted to the ink.

The pattern 10 drawn on the surface of the absorber 7 is preferably a character pattern that draws particular attention. The character pattern or the like is printed by printing on a screen plate, for example.

The colored heat-meltable substance 3 accommodated in the concave portion inside the projection 1 is a mixture of the heat-meltable substance and a dye. As the heat-fusible substance that is the main component of the colored heat-fusible substance 3, one that melts at a desired temperature is used. For example, alcohols, esters, hydrocarbon compounds, ketones,
Ethers.

Examples of the 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, cyclohexanol, and cyclohexanol. Pentanol, benzyl alcohol, cinnamyl alcohol, ethylene glycol, polyethylene glycol,
Examples include propylene glycol, trimethylolpropane, pentaerythritol, and sorbit. 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, stearin myristate, butyl palmitate, myristyl palmitate, methyl stearate, ethyl stearate, lauryl stearate, butyl benzoate,
Amyl benzoate, phenyl benzoate, ethyl acetoacetate, methyl oleate, butyl acrylate, butyl oxalate, diethyl malonate, dibutyl tartrate, dimethyl sebacate, dibutyl phthalate, dioctyl phthalate, dibutyl fumarate, diethyl maleate , Triethyl citrate, 1,2-hydroxystearic acid triglyceride, castor oil, dioxystearic acid methyl ester, 1,2-hydroxystearic acid methyl ester, and the like. Examples of the hydrocarbon compounds include aliphatic hydrocarbons such as pentadecane, tetradecane, hexadecane, 1-heptadecane and 1-octadecane, and aromatic hydrocarbon compounds such as p-xylene and dodecylbenzene. Ketones include diethyl ketone, ethyl butyl ketone, methylhexyl ketone, mesityl oxide, cyclohexanone, methylcyclohexanone, acetophenone, benzophenone, acetonylacetone, diacetone alcohol and the like. As ethers, butyl ether, hexyl ether,
Examples include diphenyl ether, dioxane, ethylene glycol dibutyl ether, diethylene glycol dibutyl ether, ethylene glycol diphenyl ether, and ethylene glycol monophenyl ether.
These can be used alone or in combination.

The dye which is the other component of the colored heat-fusible substance 3 can be used as long as it can be dissolved in the heat-fusible substance used. For example, oil-soluble dyes, direct dyes, acid dyes, basic dyes, mordant dyes, sulfur dyes, sulfur vat dyes, vat dyes, azoic dyes, disperse dyes, reactive dyes,
Oxidation dyes can be used. In some cases, a pigment may be used. Examples of the oil-soluble dye include Sudan IV manufactured by Wako Pure Chemical Industries, Ltd., and Oil Red 5B, Oil Re
d RR, Oil Orange 201, Oil Blue 2N, Oplas Violet 73
2, Oil Yellow 3G, Oil Brown BB, Oil Brown GR, Oil
Green BG, Diaresin Blue manufactured by Mitsubishi Chemical Corporation
J., Kayaset Red 802 manufactured by Nippon Kayaku Co., Ltd., and the like.

The protrusion 1 is formed of a cap that can be depressed by applying pressure with a finger or a machine, and may be any material that can be stored for a certain period of time without penetrating a heat-fusible substance. For example, polyvinyl chloride, polystyrene, non-axially oriented polypropylene, high-density polyethylene, polyethylene terephthalate, polycarbonate, non-axially oriented nylon, acrylonitrile,
Cellulose acetate is mentioned. Further, a material obtained by mixing a plurality of these materials may be used. The protrusion 1 is large enough to receive an amount of the colored heat-meltable substance 3 necessary for permeation, and may have any shape as long as the thin lid 9 can be easily broken by applying pressure.

The thin lid 9 comprises the colored heat-fusible substance 3 and the carrier 5
And an aluminum film is preferable as long as it has a thickness that can be easily broken.

The size of the hollow ring 11 is substantially the same as the diameter of the projection 1 and the height thereof may be such that the carrier 5 for absorbing the colored and heat-meltable substance 3 can be accommodated therein. Hollow ring 11
Any material can be used as long as it can hold the projection 1 and can be bonded with an adhesive, and examples thereof include nylon, polyethylene, soft vinyl chloride, Teflon, polyester, and butadiene rubber.

Such a heat-sensitive indicator is usually stored in a freezer / refrigerator or the like together with a frozen storage item, and is used for temperature control of the frozen storage item. If the absorber 7 is contaminated with the colored heat-fusible substance 3, it is determined that the storage condition is abnormal.

[0023]

When using the thermal indicator of the present invention,
After cooling the heat-sensitive indicator to solidify the colored heat-fusible substance 3, as shown in FIG.
And the colored heat-fusible substance 3 absorbed by the carrier 5 is dropped on the absorber 7. Thereafter, the colored heat-fusible substance 3 solidified by the temperature rise melts and permeates the absorber 7.

The pattern 10 drawn on the absorber 7 emerges as the colored heat-fusible substance 3 penetrates, and it can be easily visually confirmed that the temperature has reached a predetermined temperature or higher. By appropriately changing the type of the colored heat-fusible substance 3, the melting point temperature can be adjusted quite freely.

[0025]

Embodiments of the present invention will be described below. Embodiment 1 FIG. 1 is a cross-sectional view of a main part of an embodiment of a thermal indicator to which the present invention is applied.

A 28 μm-thick transparent first polyester film 15 having a polyethylene coating agent applied on one side on a backing sheet 19 is laminated, and a 1.5 cm ×
Qualitative filter paper cut to a size of 6.5 cm (Toyo Roshi Kaisha N
o. 2) The character pattern 10 is printed and laminated on the upper surface as the absorber 7. 38 μm thick on the absorber 7
The transparent second polyester film 13 is laminated.

The second polyester film 13 has a part of one end on the absorber 7 cut out in a circle having a diameter of 2 mm, and a hollow ring 11 made of ABS resin is formed around the hole 17 around the hole 17. It is erected on the second polyester film 13 via an adhesive. The size of the hollow ring 11 is 3 mm in height, 9 mm in inner diameter, 11 mm in outer diameter, and 9 mm in diameter glass fiber filter paper GA-2 which is the carrier 5 inside.
00 is stored.

A projection 1 having the same diameter as the hollow ring 11 covers the upper end of the hollow ring 11. Protrusion 1
Is formed so that it can be depressed with a bowl-shaped vinyl chloride cap having a diameter of 7.65 mmφ and a height of 4.25 mm. The inside of the projection 1 is filled with the colored heat-fusible substance 3 in an amount of 0.10 g. This colored heat-meltable substance 3 is colored blue at room temperature with 10.0 g of methyl laurate, which solidifies below the freezing point, with 0.02 g of Oil Blue2N (manufactured by Orient Chemical Co., Ltd.).

At the lower end of the projection 1, a thin lid 9 made of an aluminum film covering the upper end of the hollow ring 11 is heat-sealed inside in an airtight manner. This aluminum film is strong enough to be broken by external pressure such as finger pressure and has a thickness of 17 mm.
A lacquer of μm is applied. This is 13mmφ
It is cut out with a punch. One surface is bonded to the upper end of the hollow ring 11 with an adhesive, and the other surface is heat-sealed to the lower end of the projection 1.

On the backing sheet 19, a scale 21 is shown as shown in a perspective view in FIG. 2, which represents the distance in which the colored methyl laurate is melted and then absorbed by the absorber 7 and diffused. .

The character pattern 10 on the absorber 7 is printed on a 200-mesh screen plate to have oil repellency.
The ink composition was 20.0 g of titanium white, 30.0 g of PAS800 media manufactured by Dainippon Ink and 5.0 g of butyl cellosolve, and 1.0 g of silicon KR-5221 manufactured by Shin-Etsu Chemical Co., Ltd. Mix in proportions.

The heat-sensitive indicator was cooled at -16 ° C. for 3 hours and solidified. When the upper part of the cap was pressed with a finger, the aluminum film was torn, and the colored methyl laurate dropped onto the carrier 5 in the hollow ring 11 to enter a temperature monitoring state.

When the thermosensitive indicator in the temperature monitoring state was placed in a thermostat at 5 ° C., methyl laurate was melted and further diffused from the carrier 5 to the absorber 7. FIG. 3 shows the relationship between the penetration distance and the time. From this result, it was confirmed that this thermosensitive indicator can obtain stable permeation at the set temperature.

Example 2 The same as Example 1, except that a filter paper 526 for chromatography manufactured by Toyo Roshi Kaisha was used as the absorber 7, and its size was 2.0 × 6.0 cm. The amount of the colored heat-meltable substance 3 is not 0.01 g but 0.25 g, and the composition is also n-nonanoic acid instead of methyl laurate, and 0.02 g of Oil Blue2N (Orient 0.01 g of Oil Oran
ge 201 is used.

The same test as in Example 1 was performed, except that the temperature of the thermostat was set to 10 ° C. instead of 5 ° C. The results are shown in FIG.
It was found that stable infiltration with little variation was obtained.

Example 3 The same as in Example 1 except that qualitative filter paper (N
o. Glass fiber filter paper (GA-GA manufactured by Toyo Roshi) instead of 2)
200) are used. The results are shown in FIG.

COMPARATIVE EXAMPLE The same as in Example 1 except that the composition of the printing ink for the character pattern 10 was 30.0 g of a binder for gold and silver and 20.0 g of titanium white.
g and water 5.0 g. The same test as in Example 1 was performed. No clear characters could be seen.

[0038]

As described above in detail, according to the heat-sensitive indicator of the present invention, the colored heat-fusible substance is accommodated in the projection, does not volatilize, and is sufficiently stable even at room temperature. Can be stored. In use, it can be easily set to a predetermined monitoring state simply by pressing the projection, and the monitoring accuracy is high. Whether or not products that require low-temperature management have been sufficiently managed at or below the set temperature can be easily confirmed particularly by visually checking the emergence of the handle.

[0039]

[Brief description of the drawings]

FIG. 1 is a sectional view of a main part of an embodiment of a thermal indicator to which the present invention is applied.

FIG. 2 is a perspective view of a thermal indicator to which the present invention is applied.

FIG. 3 is a graph showing a relationship between a permeation distance and time in an example.

[Explanation of symbols]

1 is a protrusion, 3 is a colored heat-fusible substance, 5 is a carrier, 7 is an absorber, 9 is a thin lid, 10 is a handle, 11 is a hollow ring, 13, 1
5 is a polyester film, 17 is a hole, 19 is a mount, 2
1 is a scale.

Claims (3)

(57) [Claims] 1. A colored heat-meltable substance is accommodated in a concave portion inside a projection formed by a cap that can be depressed by external pressure such as a finger pressure, and an opening of the concave portion is closed by a thin lid that can be broken by the pressure. An absorber capable of penetrating the melt of the colored heat-meltable substance is disposed outside the recess through the thin lid, and the surface of the absorber is patterned with an ink that repels the melt of the colored heat-meltable substance. The heat indicator is characterized by being drawn. 2. A carrier, which is capable of adsorbing a melt of the colored heat-fusible substance, is provided in a gap formed outside the recess opening through the thin lid and below the recess, and is adsorbed by the carrier. The heat-sensitive indicator according to claim 1, wherein the absorber capable of penetrating a melt of the colored heat-meltable substance is disposed. 3. A gap in which the colored heat-fusible substance is carried by a carrier and accommodated in an inner recess of the projection, and the carrier is immersed outside through a thin lid of the recess opening due to the destruction of the thin lid. The thermal indicator according to claim 1, wherein