JPH07151613A - Thermal indicator - Google Patents

Abstract

(57) [Summary] [Purpose] A highly sensitive thermosensitive indicator that can be stored with sufficient stability in the normal temperature range, has a simple mechanism for setting a predetermined temperature monitoring state, and has very clear reaction to heat. provide. A thermosensitive indicator is a thin lid that is pressed by the colored heat-fusible substance 3 and the depression operation of the cap 1 in an internal space of a cap 1 that can be depressed by an external pressure and a thin lid 9 that closes the opening. A projecting object 23 that breaks through 9 is stored. An absorber 7 that absorbs the molten liquid of the colored heat-fusible substance 3 and permeates it to the visible position is disposed outside the thin lid 9. A carrier 5 capable of adsorbing the molten liquid is provided in the space between the thin lid 9 and the absorber 7.

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 preset temperature and is used for low temperature control in the frozen food and medical fields.

[0002]

2. Description of the Related Art In recent years, many foods controlled at low temperatures have been used in dietary habits. Foods that require low-temperature control have a considerable difference in storage temperature depending on the type. When these products are transported, if the product temperature rises, the quality of the products may deteriorate, or bacteria may propagate and cause deterioration or decay. Also in the medical field, the role of low-temperature control of special medicines, blood, specimens, etc. is extremely important. These products not only lead to deterioration in quality when the product temperature rises, but may also become unusable. For this reason, strict monitoring and recording of temperature control of such products and heat retention during distribution were required.

The use of a heat sensitive indicator is one of the means for continuously monitoring the storage temperature of frozen stocks. For example, JP-A-50-60262 and JP-A-51
-33432 and JP-A-5-72045 describe a time-temperature integrating type monitor showing a temperature history. JP-A-61-113116 and JP-A-62-1
Japanese Patent No. 97486 discloses a temperature-time monitor using microcapsules. JP-A-59-164
929 and Japanese Patent Laid-Open No. 59-175172 describe an indicator utilizing the capillary phenomenon.

[0004]

When storing in a freezer / refrigerator, it is very difficult to actually monitor the storage temperature because the temperature history is complicated. When the temperature is monitored by the heat sensitive indicator, the indicator is cooled to the temperature inside the refrigerator to be monitored and then set to a predetermined monitoring state.
The timing to set the monitoring state is difficult, and the mechanism itself for starting the monitoring state is complicated. The indicators include
Contains a substance that senses temperature changes in the low temperature range. This substance is very volatile at room temperature. The volatility reduces the accuracy of the thermal indicator and makes it difficult to store the thermal indicator itself. Further, there is a problem that it is unclear whether or not there is a reaction to heat.

The present invention has been made in order to solve the above-mentioned problems, and it can be stored in a sufficiently stable manner even at room temperature, the mechanism for setting a predetermined temperature monitoring state is simple, and the presence or absence of reaction to heat is extremely high. It is an object to provide a heat sensitive indicator that is clear and highly accurate.

[0006]

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.

As shown in FIG. 1, the heat-sensitive indicator of the present invention comprises a colored heat-fusible substance 3 and a cap in the inner space of a cap 1 which can be depressed by an external pressure and a thin lid 9 which closes its opening. A protrusion 23 that is pushed by the depression operation 1 and breaks through the thin lid 9 is stored. An absorber 7 that absorbs the molten liquid of the colored heat-fusible substance 3 and permeates it to the visible position is disposed outside the thin lid 9.

A carrier 5 capable of adsorbing the melt is provided in the space between the thin lid 9 and the absorber 7. The hollow ring 11 may be integrated with the main body holding the absorber 7 and the carrier 5 that allow the melt to permeate.

The cap 1 has a hemispherical shape, as long as the colored heat-fusible substance 3 can be put therein. The cap 1 is made of a material that does not allow the heat-fusible substance to pass through and can be stored for a certain period of time, such as polyvinyl chloride, polystyrene, non-axially oriented polypropylene, high density polyethylene, polyethylene terephthalate, polycarbonate, non-axially oriented nylon, acrylonitrile, and cellulose acetate. Is mentioned.
Further, a material in which a plurality of these are mixed may be used.

The thin lid 9 is preferably made of aluminum foil having a thickness capable of closing the opening of the hemispherical cap 1, holding the colored heat-fusible substance 3 and the carrier 5, and easily breaking.

The colored heat-fusible substance 3 contains a heat-fusible substance and a dye. The heat-fusible substance which is the main component of the colored heat-fusible substance 3 includes substances that melt at a desired temperature, such as alcohols, esters, hydrocarbon compounds, ketones, ethers, inorganic type and organic type substances. An aqueous solution of a freezing point depressant is included.

Alcohols include n-octyl alcohol, n-nonyl alcohol, n-decyl alcohol, and n.
-Lauryl alcohol, n-myristyl alcohol, n
-Cetyl alcohol, n-stearyl alcohol, olein alcohol, cyclohexanol, cyclopentanol, benzyl alcohol, cinnamyl alcohol, ethylene glycol, polyethylene glycol, propylene glycol, trimethylolpropane, pentaerythritol, sorbit and the like can be mentioned.

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, ethyl stearate, lauryl stearate, butyl benzoate, amyl benzoate, phenyl benzoate, ethyl acetoacetate, oleic acid Methyl, 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, etc. dioxy stearic acid methyl ester.

The hydrocarbon compounds include aliphatic hydrocarbons such as pentadecane, tetradecane, hexadecane, 1-heptadecane, 1-octadecane, and aromatic hydrocarbon compounds such as p-xylene and dodecylbenzene.

Ketones include diethyl ketone, ethyl butyl ketone, methylhexyl ketone, mesityl oxide,
Examples thereof include 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.

Aqueous solutions of inorganic and organic freezing point depressants include sodium carbonate, ammonium hydrogen carbonate, potassium hydrogen carbonate, ammonium chloride, potassium chloride, sodium chloride, magnesium chloride, calcium chloride, sodium nitrate, ammonium nitrate, urea and carbonic acid. Examples thereof include aqueous solutions of sodium hydrogen, sodium thiosulfate, glucose, sucrose, fructose and the like. Also, water alone may be used. These heat-meltable substances may be used alone or in a mixture.

The dye which is the other component of the colored heat-fusible substance 3 may be any dye that can be dissolved in the heat-fusible substance. Examples thereof 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, and oxidation dyes. A pigment may be used depending on the case. Specific examples of the oil-soluble dye include Sudan IV manufactured by Wako Pure Chemical Industries, Ltd., Oil Red 5B, Oil Red RR, Oil Or manufactured by Orient Chemical Industry.
ange 201, Oil Blue 2N, Oplas Violet 732, OilYellow
3G, Oil Brown BB, Oil Brown GR, Oil Green BG,
Examples include Diaresin Blue J manufactured by Mitsubishi Chemical Co., Ltd. and Kayaset Red 802 manufactured by Nippon Kayaku Co., Ltd. Diacellition Fast manufactured by Mitsubishi Chemical Industries, Ltd.
Violet B, Diacellition Fast Brilliant Blue BM / D,
Nippon Kayaku Co., Ltd. Kayalon FastBrilliant Green GC
Is mentioned.

The protrusion 23 has a conical shape capable of reliably breaking the thin lid 9 at one point, and is arranged inside the cap 1.

The absorber 7 is preferably one that allows the colored heat-fusible substance 3 to permeate stably. For example, porous films, qualitative filter papers, quantitative filter papers, glass fiber filter papers, filter papers such as chromatography filter papers, pulp, cotton, non-woven fabrics, silica gel, porous inorganic sintered bodies, and composites prepared by mixing a plurality of these may be used. Can be mentioned.

The carrier 5 has a function of controlling the permeation rate of the colored heat-fusible substance 3. The carrier 5 preferably has a slightly weaker force for absorbing the colored heat-fusible substance 3 than the absorber 7. Examples thereof include glass fiber filter paper, chromatography filter paper, pulp, powder filter paper, and fine powder silica gel. Of these, glass fiber filter paper is particularly preferable. The carrier 5 may be enclosed inside the cap 1 or may be arranged inside the hollow ring 11 on the absorber 7.

The size of the hollow ring 11 is about the same as the diameter of the cap 1, and the height may be such that the carrier 5 for absorbing the colored heat-fusible substance 3 is housed inside. The hollow ring 11 may be made of any material as long as it can hold the cap 1 and can be bonded with an adhesive. For example, nylon, polyethylene, soft vinyl chloride, Teflon, polyester, butadiene rubber, A
BS is mentioned.

[0023]

When the heat sensitive indicator of the present invention is used, it is cooled to solidify the colored heat-fusible substance 3. Then, Figure 1
When pressure is applied to the cap 1 as shown in FIG.
3 reliably breaks the thin lid 9 at one point and drops the colored heat-fusible substance 3 on the carrier 5. The colored heat-fusible substance 3 is absorbed by the carrier 5, melts and permeates into the absorber 7 when the temperature rises.
By visually confirming the permeation distance of the colored heat-fusible substance 3, an increase in storage temperature can be easily confirmed.

[0024]

EXAMPLES Examples of the present invention will be described in detail below. FIG. 1 is a sectional view of a main part of a heat sensitive indicator to which the present invention is applied, and FIG. 2 is a perspective view of the heat sensitive indicator to which the present invention is applied.

The thermosensitive indicator of the present invention is manufactured as follows. Absorber 7 is polyester film 13/15
Sandwich and heat seal. Centering around the non-sealed portion of the absorber 7, the hollow ring 11 is attached to the polyester film 1
Adhere to 3. The carrier 5 is arranged inside the hollow ring 11. The colored heat-meltable substance 3 is added to the cap 1 provided with the protrusions 23, and the opening of the cap 1 is closed with the thin lid 9. With the thin lid 9 down, the hollow ring 11 and the cap 1
And are used as a heat sensitive indicator. This heat sensitive indicator is fixed on the mount 19. The mount 19 has an absorber 7
A scale 21 indicating the permeation distance of the colored heat-fusible substance 3 is displayed.

When pressure is applied to the cap 1, the protrusions 2
3 reliably breaks the thin lid 9 at one point, and the colored heat-fusible substance 3 is absorbed by the carrier 5. As the temperature rises, the colored heat-fusible substance 3 melts and permeates the absorber 7. Penetration distance is mount 19
Since it is confirmed by the upper scale 21, the temperature rise can be easily confirmed.

Example 1 The absorber 7 is a porous film made of polytetrafluoroethylene fiber and silica gel (trade name: Thin Layer Chrom
atography Sheets 3M Co., Ltd.) 0.5 cm x 6.0
A piece cut to a size of cm was used. This absorber 7
It was sandwiched between a polyester film 13 having a thickness of 32 μm and a polyester film 15 having a thickness of 28 μm coated with a polyethylene sealant on one side, and heat-sealed at 120 ° C. At the time of heat sealing, a non-sealed portion was made by leaving one end of the absorbent body 5 mm. Next, centering on the non-sealed portion of the absorber 7, the height is 3 mm, the inner diameter is 9 mmφ, and the outer diameter is 11 mmφ.
The ABS hollow ring 11 was bonded to the polyester film 13 with an adhesive. Glass fiber filter paper G as carrier 5
A-200 (manufactured by Toyo Roshi Kaisha, Ltd.) was cut into a size of 8.8 mmφ and placed inside the hollow ring 11. A 200 μm-thick polyvinyl chloride was formed into a dome shape having a size of 7.65 mmφ and a height of 4.25 mm to form a cap 1, and a protrusion 23 having a length of 4 mm was provided inside. Coloring fusible substance 3
0.1 g was added to the cap 1. Coloring fusible substance 3
Is a surfactant, 0.5 g of Neoperex F-25 (manufactured by Kao Corporation) is added to 50.0 g of water, and is colored blue with 0.04 g of Brilliant Blue (manufactured by Daiwa Kasei Co., Ltd.). There is. Next, lacquer applied thickness 15μ
The opening of the cap 1 was sealed with aluminum foil 9 of m. Then, the periphery of the cap 1 was cut with a punch of 13 mmφ, and the aluminum foil 9 was faced down to be bonded on the hollow ring 11 with an adhesive to obtain a heat sensitive indicator.

The heat sensitive indicator was cooled at -16 ° C. for 3 hours to be solidified. Then, the penetration test was conducted as follows. When the upper part of the cap 1 was pushed with a finger, the aluminum foil 9 was broken at one point by the protrusion 23, and the heat sensitive indicator entered the temperature monitoring state. When the thermosensitive indicator that has entered the temperature monitoring state is placed in a constant temperature bath of 0 ° C., the solidified colored fusible substance 3 gradually dissolves as the temperature rises, and the carrier 5
It diffused into the absorber 7. With this heat sensitive indicator, stable penetration was obtained at the set temperature.

Example 2 Quantitative filter paper No. 1 manufactured by Toyo Roshi Kaisha, Ltd. 5 mm for 514-A
It was cut into a size of 33 mm to obtain an absorber 7, and the glass fiber filter paper GA-200 was cut into a size of 9.2 mm to obtain a carrier 5. These were integrally molded with a silicone adhesive. Colored heat-fusible substance 3 is 50.0 g of decyl alcohol
Red 5B (manufactured by Orient Chemical Co., Ltd.) was colored with 0.05 g. After the colored decyl alcohol is melted on the mount paper 19, a scale 21 indicating the distance that the absorbent body 7 absorbs moisture and diffuses is displayed. 0.1 g of the coloring heat-fusible substance 3 was poured into the cap 1 and the thickness was 15 μm.
A heat-sensitive indicator was prepared by enclosing it in an aluminum foil coated with a heat-melt-adhesive coating agent and incorporating it into an integral molding.

Using this thermosensitive indicator, a penetration test was conducted in a constant temperature bath at 7 ° C. Table 1 shows the measurement results of the elapsed time after the start of the test and the permeation distance. The number of samples is 100
It is an individual. Also in this case, stable permeation with little variation was obtained.

Comparative Example FIG. 3 is a perspective view of a heat sensitive indicator to which the comparative example is applied. The heat-sensitive indicator shown in the same drawing is the same as the heat-sensitive indicator used in Example 2 except that there is no protrusion 23, and the polyester film on the absorber 7 is hollowed out in a circular shape to have holes 17. . The same penetration test as in Example 2 was conducted using this heat sensitive indicator. Table 1 shows the elapsed time after the start of the test and the results of the permeation distance. The permeation distance obtained in the comparative example had a larger variation than the permeation distance obtained in Example 2 (100 samples).

[0032]

[Table 1]

Example 3 As the absorber 7, a 5 mm × 33 mm quantitative filter paper No. manufactured by Toyo Roshi Kaisha, Ltd. was used. 6 was used, and 50.0 g of pelargonic acid as the coloring heat-melting substance 3 was colored with 0.05 g of Oil Blue 2N (manufactured by Orient Chemical Co., Ltd.), and the same thermosensitive indicator as in Example 2 was produced. . As a result of performing the penetration test in the same manner as in Example 2, stable penetration with little variation was obtained.

[0034]

As described in detail above, according to the heat sensitive indicator of the present invention, the temperature history of frozen foods and medical products during low temperature control can be visually confirmed, so that temperature control is easy. Since the colored heat-fusible substance is enclosed in the cap, it does not volatilize and can be used stably even at room temperature. The heat sensitive indicator can be easily set to the temperature monitoring state by pushing the cap. Since the protrusions disposed inside the cap broke the aluminum foil at one point, the starting point of permeation of the colored heat-fusible substance became constant, and the error in permeation distance seen so far was resolved. Further, since the permeation rate can be controlled by changing the carrier, the accuracy of the indicator is also improved.

[Brief description of drawings]

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

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

FIG. 3 is a perspective view of a heat sensitive indicator to which a comparative example is applied.

[Explanation of symbols]

1 is a cap, 3 is a colored heat-fusible substance, 5 is a carrier, 7 is an absorber, 9 is a thin lid, 11 is a hollow ring, 13/15 is a polyester film, 17 is a hole, 19 is a mount, 21 is a scale, Reference numeral 23 is a protrusion.

Claims (2)

[Claims] 1. A colored heat-fusible substance in an inner space of a cap that can be depressed by an external pressure and a thin lid that closes an opening of the cap,
Also, a protrusion that is pushed by the depression operation of the cap and breaks through the thin lid is accommodated, and an absorber that absorbs the molten liquid of the colored heat-meltable substance and permeates it to the visible position is arranged outside the thin lid. A heat-sensitive indicator characterized by being. 2. A carrier capable of adsorbing a molten liquid is provided in a space between the thin lid and the absorber.
Heat sensitive indicator as described in.