JPH0650826A - Heat-sensitive indicator - Google Patents

Abstract

(57) [Abstract] [Purpose] An object of the present invention is to provide a heat sensitive indicator that can be stored in a stable condition for a long time even at room temperature, has a simple mechanism for setting a predetermined temperature monitoring state, and has high accuracy. [Structure] Water 3 is stored in an inner concave portion of a protrusion 1 formed of a film that can be depressed by an external pressure such as finger pressure, and the opening of the concave portion is closed by a thin lid 9 that can be broken by the above-mentioned pressure. An absorber 7 capable of penetrating the water 3 is arranged outside the recess via the thin lid 9. The water 3 is carried by the carrier 5 and stored in the inner recess of the protrusion 1. The carrier 5 is
It may be arranged on the absorber 7 on the outside of the recess opening through the thin lid 9 and on the inside of the hollow ring 11 that forms a void below the recess. After cooling the thermosensitive indicator and freezing the water 3, pressure is applied to the protrusions 1 to break the thin lid 9. Absorber 7
If the carrier 5 is placed on the carrier 5, the solid water 3 falls on the carrier 5. The solidified water 3 returns to a liquid state again due to the temperature rise and permeates the carrier 5, and then permeates the absorber 7.

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 the temperature along with the stored items. 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 known in Japanese Patent Laid-Open Nos. 50-60262 and 51-33432.
A temperature-time monitor using microcapsules is disclosed in JP-A-61-13116 or JP-A-62-19.
It is known from Japanese Patent No. 7486. There is also an indicator utilizing the capillary phenomenon, which is disclosed in JP-A-59-164.
It is known in Japanese Patent Laid-Open No. 929 and Japanese Patent Laid-Open No. 59-175172.

[0005]

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, to start temperature monitoring, 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
At room temperature, it may evaporate very easily, and storage is difficult. If volatilized, the accuracy of the heat sensitive indicator will naturally drop.

The present invention has been made to solve the above-mentioned problems, and it can be stably stored for a long period of time at room temperature.
The purpose of the present invention is to provide a heat sensitive indicator which has a simple mechanism for setting a predetermined temperature monitoring state and is highly accurate.

[0007]

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. It should be noted that FIG. 1 shows a situation when the heat sensitive indicator is about to be set in the temperature monitoring state. In the figure, water 3 is stored in an inner concave portion of a protrusion 1 formed of a cap that can be depressed by an external pressure such as finger pressure. The opening of the recess is a thin lid that can be destroyed by the above pressure
Is blocked by. Water 3 is placed on the outside of the recess through the thin lid 9.
An absorber 7 that is capable of penetrating is disposed.

The water 3 is stored in the inner recess of the protrusion 1. A void is formed by a hollow ring 11 on the outer side of the opening of the recess via the thin lid 9. The carrier 5 is arranged inside the hollow ring 11 and on the absorber 7. As shown in FIG. 2, the carrier 5 may be housed in a recess inside the protrusion 1 to absorb the water 3.

The carrier 5 has a function of controlling the permeation rate of the water 3, and the carrier 5 can provide stable permeation in the absorber 7. Therefore, the carrier 5 may be enclosed in the recess of the protrusion 1 or may be arranged on the absorber 7 inside the hollow ring 11. The carrier 5 is preferably one that absorbs water 3 well and has a slightly weaker absorption power than the absorbent body 7, and 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.

It is preferable that the absorbent body 7 carry water 3 and obtain stable permeation, for example, a porous film, a qualitative filter paper,
Examples include filter papers such as quantitative filter paper, glass fiber filter paper, filter paper for chromatography, pulp, cotton, non-woven fabric, silica gel, porous inorganic sintered body, and composites obtained by mixing a plurality of these.

It is preferable that the water 3 contained in the concave portion of the protrusion 1 dissolves the freezing point depressant. In that case, the freezing point depressant may be an organic freezing point depressant or an inorganic freezing point depressant. Organic freezing point depressants include urea and its derivatives, ethylene glycol, polyethylene glycol,
Examples thereof include polypropylene glycol, propylene glycol, sugars and the like. Examples of the inorganic freezing point depressants include sodium chloride, ammonium chloride, magnesium chloride, calcium chloride, potassium acetate, sodium nitrate and the like. The addition concentration of the freezing point depressant is generally 0 to 4.5 mol / liter.

It is preferable that the water 3 is colored with a coloring agent and that a surfactant is added. Any colorant can be used as long as it is soluble in water 3. For example, oil-soluble dyes, direct dyes, acid dyes, basic dyes, mordant dyes, sulfur dyes,
Sulfurized vat dyes, vat dyes, azoic dyes, disperse dyes,
Reactive dyes and oxidation dyes can be used. A pigment may be used depending on the case. As the disperse dye, for example, Diacelliton Fast Scarlet RM / D, Di manufactured by Mitsubishi Chemical Industry Co., Ltd.
acelliton Fast Violet B, Diadelliton Fast Brilli
ant Blue BM / D, etc., manufactured by Nippon Kayaku Co., Ltd.
Kayalon FastRed R, Kayalon Fast Blue FR, Kaya
Examples include lon Fast Brilliant Green GG. The amount of colorant added does not matter. It suffices if the water 3 is colored, and it is usually a trace amount.

The protrusion 1 may be formed of a cap that can be depressed by applying pressure with a finger or a machine and can be stored for a certain period of time without penetrating the water 3. Examples thereof include polyvinyl chloride, polystyrene, non-axially oriented polypropylene, high density polyethylene, polyethylene terephthalate, polycarbonate, non-axially oriented nylon, acrylonitrile, and cellulose acetate. Further, a material in which a plurality of these are mixed may be used. The protrusion 1 has a volume of water 3 required for permeation.
Any shape may be used as long as it can be inserted, and the thin lid 9 can be easily broken by applying pressure.

The thin lid 9 can carry water 3 and the carrier 5 and has a thickness such that it can be easily broken, and an aluminum foil is preferable.

The size of the hollow ring 11 is about the same as the diameter of the projection 1, and the height thereof may be such that the carrier 5 that absorbs the water 3 can be housed inside. The hollow ring 11 may be made of any material as long as it can hold the protrusion 1 and can be bonded with an adhesive,
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 together with a frozen storage product and used for temperature control of the frozen storage product. If the absorber 7 is soiled with the water 3, it is determined that the storage condition is abnormal.

[0017]

When the heat sensitive indicator of the present invention is used,
After cooling the heat sensitive indicator and solidifying the water 3, the thin lid 9 is broken by applying pressure to the protrusion 1 as shown in FIG. If the carrier 5 is arranged on the absorber 7, the solid water 3 falls on the carrier 5. The solidified water 3 returns to a liquid state by the temperature rise and permeates the carrier 5, and then the absorber 7
Permeate into. If you change the type of freezing point depressant appropriately,
The melting temperature of ice can be adjusted quite freely.

[0018]

EXAMPLES Examples of the present invention will be described below. Example 1 FIG. 2A is a sectional view of an example of a heat sensitive indicator to which the present invention is applied. A transparent first polyester film 15 having a thickness of 28 μm and coated on one side with a polyethylene coating agent is laminated on a mount 19, and 0.5c is formed thereon.
A porous film cut into a size of m × 6.0 cm is laminated as an absorber 7, and a thickness of 38 μ is formed on the absorber 7.
m of transparent second polyester film 13 is laminated. 3M Thin Layer Chr for porous film
Omatography Sheets are used. The first and second polyester films 13 and 15 and the porous film are 1
It is heat-sealed at 20 ° C.

In the second polyester film 13, a part of one end portion on the absorbent body 7 is hollowed out in a circular shape having a diameter of 4 mm, and a hollow ring 11 made of polyethylene is surrounded by a hole 17 to form a second hollow ring 11. It is erected on the polyester film 13 via an adhesive. The size of the hollow ring 11 is 3 mm in height, 9 mmφ in inner diameter, and 11 mmφ in outer diameter.

At the upper end of the hollow ring 11, the hollow ring 11
Is covered with a protrusion 1 having the same diameter. The protrusion 1 is a bowl-shaped polyvinyl chloride cap having a diameter of 7.65 mmφ, a height of 4.25 mm, and a thickness of 200 μm, and is formed so as to be depressed by an external pressure such as finger pressure. Inside the protrusion 1, 0.1 g of water and a carrier 5 that absorbs and carries the water are contained. In the water, the surfactant Neoperex F-25 manufactured by Kao Corporation and the blue dye Brilliant Blue manufactured by Daiwa Kasei Co., Ltd. were added to 0.5 g of the surfactant and 0.5 g of the dye for 50 g of water, respectively. It was added at a concentration of 0.04 g. The carrier 5 is a glass fiber filter paper GA-having a diameter of 9 mm.
It is formed of 200.

A thin lid 9 made of aluminum foil covering the upper end of the hollow ring 11 is heat-sealed inside the lower end of the protrusion 1 in an airtight manner. This aluminum foil has a strength such that it can be destroyed by an external pressure such as finger pressure, and is coated with a lacquer having a thickness of 17 μm. It should be noted that this is formed by cutting with a punch of 13 mmφ. 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 protrusion 1.

As shown in FIG. 3, on the mount 19, a scale 21 is displayed which represents the distance after the colored methyl laurate is melted and then absorbed by the absorber 7 and diffused.

The heat-sensitive indicator thus formed was cooled at minus 16 ° C. for 3 hours to freeze the water in the projection 1. When the upper part of the protrusion 1 was pressed with a finger, the aluminum foil was broken, and the ice dropped into the hollow ring 11 together with the carrier 5 as shown in FIG. 2B to enter the temperature monitoring state. The thermosensitive indicator that entered the temperature monitoring state was placed in a constant temperature bath of 0 ° C., and the state of water permeation into the absorber 7 was observed. A stable permeation phenomenon with little variation in permeation distance was confirmed.

Example 2 The same as Example 1, except that a quantitative filter paper No. 2 manufactured by Toyo Roshi Kaisha, Ltd. was used as the absorbent body 7 instead of the porous film, and the size thereof was 1.0 × 6.0 cm. The amount of water in the cap of the protrusion 1 was 0.2 g instead of 0.1 g.
It is prepared with the composition of.

Table 1 Water 50 g Eosin GH (manufactured by Daiwa Kasei Co., Ltd.) 0.04 g Calcium chloride (manufactured by Kanto Kagaku Co., Ltd.) 7.28 g Polyethylene glycol 2.0 g NEOPEREX SSH Kao Co., Ltd. 0.5 g Minus The penetration test was conducted in a constant temperature bath at 10 ° C. It was found that stable penetration with little variation can be obtained in this case as well.

Example 3 The same as Example 1, except that a glass fiber filter paper GA-200 manufactured by Toyo Roshi Kaisha, Ltd. was cut into a size of 1.0 × 6.0 cm and used as the absorber 7 instead of the porous film. Has been. It was found that stable penetration with little variation can be obtained in this case as well.

[0027]

As described above in detail, according to the thermosensitive indicator of the present invention, water is stored and stored in the protrusions at room temperature, does not volatilize, and is stably stored even at room temperature. It is possible to set it to a predetermined monitoring state simply by pushing the protrusion. High accuracy. It is easy to visually confirm whether or not the products requiring low-temperature control have been sufficiently controlled within the set temperature.

[Brief description of drawings]

FIG. 1 is a sectional view of an essential part of an embodiment of a heat-sensitive indicator to which the present invention is applied.

FIG. 2 is a cross-sectional view of the essential parts of another embodiment 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 the present invention is applied.

[Explanation of symbols]

1 is a protrusion, 3 is water, 5 is a carrier, 7 is an absorber, 9 is a thin lid,
11 is a hollow ring, 13 and 15 are polyester films, 17 is a hole, 19 is a mount, and 21 is a scale.

Claims (5)

[Claims] 1. Water is stored in an inner concave portion of a protrusion formed of a cap that can be depressed by an external pressure such as finger pressure, and the opening of the concave portion is closed by a thin lid that can be broken by the pressure, A heat-sensitive indicator, wherein an absorber capable of penetrating water is arranged on the outside through the thin lid. 2. The water is carried on a carrier and is stored in an inner concave portion of the projection, and a void is formed outside the concave opening through the thin lid into which the carrier is immersed by the destruction of the thin lid. The thermosensitive indicator according to claim 1, wherein the thermosensitive indicator is provided. 3. A carrier capable of adsorbing the water is provided in a void formed outside the recess opening and below the recess, and the water is adsorbed by the carrier. The heat sensitive indicator according to claim 1, wherein the absorber is arranged. 4. The heat sensitive indicator according to claim 1, wherein a freezing point depressant is dissolved in the water. 5. The heat sensitive indicator according to claim 1, wherein the water is colored and a surfactant is added.