JPS6055235A - Temperature indicating sheet - Google Patents

Abstract

PURPOSE:To enable easy detection of whether an article preserved by refrigeration or the like is held at a prescribed temp. or not by using the sheet formed by laminating successively a capsule layer contg. a component A which melts at the prescribed temp., a diaphragm which allows permeation of the molten component A and a layer contg. a component B which discolors by the permeated component A. CONSTITUTION:An electron donative colorable org. compd., for example, crystal violet lactone 2, is incorporated into a wax-like component 2 which melts at a prescribed temp. Said component is enclosed in a microcapsule 4 of gelatin, etc. The capsule 4 is so formed that the capsule is easily pressed to discharge the content. An aq. PVA soln. dispersed therein with such capsule is coated on a diaphragm 5 such as paper, non- woven fabric or the like and is dried. A material prepd. by dispersing a coloring material 3 such as activated clay, solid inorg. acid or the like which discolors when the material contacts with the material 1 in an aq. PVA soln. is coated on the opposite side of the diaphragm 5 and is dried. Such laminated sheet is put together with an article preserved by refrigeration or the like into a refrigerator, etc. and the capsule is pressed at the prescribed temp. or below to discharge preliminarily the content. When the sheet is exposed to the prescribed temp. or above for specified time or above, the sheet discolors irreversibly.

Description

[Detailed description of the invention] The present invention relates to a temperature indication sheet.

Products stored at low temperatures, such as frozen products, usually change in quality once they are exposed to an environment at a predetermined temperature or higher, but if the deteriorated products are stored at low temperatures again, they may become indistinguishable from unaltered products in terms of appearance. In order to check in advance for deterioration due to poor management of low-temperature-preserved products along the sales route, and to supply products without deterioration to consumers with confidence, it is necessary to ensure that low-temperature-preserved products are not exposed to temperatures higher than the specified temperature during the process. It is necessary to be able to easily judge things.

An object of the present invention is to provide such a temperature indicator, which can be attached directly to a low-temperature-preserved product, but can be inserted or pasted into a package to prevent the low-temperature-preserved product from being exposed to a temperature higher than a predetermined temperature. The present invention relates to a temperature indication sheet that changes color depending on temperature and time.

Conventionally, thermochromic materials include electron-donating color-forming organic compounds, electron-accepting organic compounds, alcohols, esters, etc., in place of metal complex crystals or liquid crystals, which are limited in the color-changing temperature range and type of color. Thermochromic compositions consisting of electron-accepting color-changing organic compounds, electron-donating organic nitrogen compounds, alcohols, esters, etc. have been proposed. Although it is possible to freely select the discoloration temperature range and color type over a wide temperature range,
As the object of the present invention, a composition that changes color depending on temperature and time has not yet been provided.

In addition, in a thermochromic composition consisting of a combination of an electron-donating color-forming organic compound and an electron-accepting compound, one of the components is
A heat-integrating thermochromic composition has also been proposed, in which the discoloration property is dependent on two items, time and temperature, by encapsulating the two in microcapsules and heating them at a predetermined temperature for a predetermined time to destroy the microcapsules. However, in this case, the microcapsules are destroyed and the composition changes color when heated to a temperature higher than room temperature, and is therefore not applicable to low-temperature preservation products as the object of the present invention. For temperature display at low temperatures, a method has been proposed that detects changes in shape or color tone (combined with dyes) when frozen brine melts, but in the case of rice, the temperature that can be controlled is below 0°C, and Since changes depending on temperature and time cannot be detected, this method is not suitable for the present invention, which aims at managing general low-temperature storage materials including temperatures of 0° C. or higher.

The inventors of the present invention previously proposed a temperature indicator label that changes color after a certain period of time at a certain temperature (Japanese Patent Application No. 1983-64352).
This temperature indicator label required manufacturing and storage below the discoloration temperature, making it inconvenient to use.

In order to solve these problems with the conventional technology, we have developed a temperature instruction sheet that changes color depending on the temperature and time when it is exposed to a temperature higher than a predetermined temperature in the temperature control of general low-temperature storage items. As a result of research, it was discovered that the object can be achieved by a combination of a substance that melts at a predetermined temperature and a substance that irreversibly changes color upon contact with the substance, and the present invention has been achieved.

That is, the present invention provides a component (A) that melts at a predetermined temperature,
A substance (B) that causes discoloration upon contact with component (A), a diaphragm through which the molten component (A) can pass, and component (A) is encapsulated in microcapsules that can be destroyed by external pressure at the usage temperature. , relates to a temperature indicating sheet in which component (A) and substance (B) are placed on opposite sides with a diaphragm interposed therebetween.

The basic structure of the temperature indication sheet of the present invention will be explained based on FIGS. 1 to 3.

In Figure 1, the component (A) that melts at a predetermined temperature is a coloring agent (]
) and a wax-like substance (2), which are microencapsulated and applied to the negative side of the diaphragm (5). on the other hand,
A color-changing agent (3) (substance (B)) that causes discoloration upon contact with the color-forming agent (1) is applied to the opposite surface of the diaphragm.

As used herein, the term waxy substance (2) refers to the use temperature, i.e.
This term refers to a substance that exhibits a wax-like appearance when this sheet is applied to frozen foods and is stored at low temperatures, but does not refer to a substance that exhibits a wax-like appearance at room temperature.

Since the waxy substance is microencapsulated, it will not melt and come into contact with the color change agent (3) even if it is manufactured and stored above its melting point.

After pasting the sheet on a frozen food, etc., pressure is applied to the sheet using an appropriate method such as a roller or a stapler to destroy the microcapsules. At this time, since the wax-like substance is solidified, it does not discolor the sheet.

When frozen foods, etc. reach a certain temperature or higher, Wa-Nx melts and oozes out from the damaged part of the microcapsules together with the coloring agent (1) dissolved or dispersed therein, forming a layer (C) (usually , the diaphragm (5)) and comes into contact with the color change agent (3), causing a change in color.

In the sheet shown in Figure 1, frozen foods, etc. can be attached to either the upper or lower side, but when using an opaque material such as paper as a diaphragm, it is preferable to attach the layer containing the component that melts immediately on the upper side, or on the 4 sides. is preferred.

In Figure 2, the component (A) that melts at a certain temperature is a color change agent (3).
and a wax-like substance (2), which is self-encapsulated by the microphone. Substance (B) contains a color former (1), and both are placed on opposite sides of a diaphragm (5). Destroy the capsule upon use.

In this case, when the frozen food or the like is kept at a predetermined temperature or higher for a certain period of time, the color change agent (3) leached from the capsule passes through the diaphragm together with the molten wax, contacts the color forming agent (1), and changes color.

Figure 3 shows a wax-like substance (2) in which the component (A) that melts at a predetermined temperature is encapsulated in microcapsules, and the substance (B) that causes discoloration upon contact with the component (A) is a color forming agent (1) and discoloration. It is composed of agent (3). This substance (B) has a specific color, but this is due to the presence of components that contribute to erasing the coloring substance (<A) + (B)) of the wax-like substance (usually alcohol, etc.). (The term "discoloration" in the present invention is used to include such discoloration).

After pasting the sheet, destroy the microcapsules.

When left at a predetermined temperature for a predetermined period of time, a waxy substance melted and exuded from the broken capsule passes through the diaphragm over time, decolorizing the coloring layer.

As shown in the above embodiment, when the component (A) is applied on the diaphragm containing the substance (B) by being encapsulated in microcapsules, and the microcapsules are destroyed, the entire system is immediately stored within a predetermined temperature range. Although no particular change occurs on the sheet,
If the system is exposed to a temperature above the melting temperature of component (A), component (A) will melt and diffuse through the diaphragm;
The irreversible color change upon contact with substance (B) confirms that the system has been exposed to temperatures above the melting temperature of component (A).

In this case, if the time of exposure above the melting temperature of component (A) is short, even if component (A) once melts and begins to diffuse through the diaphragm, it will solidify again before it comes into contact with substance (B). , substance (B) does not change color.

Therefore, by appropriately selecting the diaphragm, substance (B)
You can adjust the time it takes for the color to change.
Depending on the temperature and time, a color change is possible when the entire system is exposed to a temperature above a predetermined temperature.

The main purpose of the present invention is to preserve and manage products stored at low temperatures.1) The melting temperature of component (A) is 20°C, but for normal use, the preferred temperature range is 5 to 20°C, especially around 10°C. Therefore, microcapsules containing component (A) must be applied onto a membrane containing substance (B) and destroyed during use. If the microcapsules of component (A) are not stored at the specified temperature immediately after destruction, the component (A)
A) melts and begins to diffuse and permeate, discoloring the substance (B) and making it unsuitable for its original purpose.

Examples of combinations of color former (1) and color change agent (3) used in the present invention are as follows.

(i) Electron-donating color-forming organic compounds (color-forming agents) and acids (phenolic hydroxyl group-containing compounds, organic carboxylic acids, solid acids, etc.) (color-changing agents) (subject) pH indicators (color-forming agents)
and acid or alkali (color change agent) (iii) Iron compound and polyhydric hydroxy compound having phenolic hydroxyl group Examples of electron-donating color-forming compounds used in the present invention include polyaryl heptadides, polyaryl heptadides, Examples include 7-ols, leucoolamines, acylouramines, arylauramines, rhodamine B-lactams, indolines, spiropyrans, fluorans, and the like.

Examples of these compounds are shown below.

Crystal violet lactone, malachite green lactone, Michler hitrol, crystal violet carpinol, malachite green carbyl, N
-(2,3-dichlorophenyl)leuforamine, N
-benzoyl auramine, N-acetyl auramine, N
-Phenyluramine, Rhodamine B-lactam, 2-(
phenyliminoethanedylidene) 3,3-dimethylindoline, N-3,'3-trimethylindolinobenzospiropyran, 8'-methoxy-N-3,3-)limethylindolinobenzospiropyran, 3-diethylamino -6-Methyl-7-chlorofluorane, 3-diethylamino-7-methoxyfluorane, 3-diethylamino-6-benzyloxyfluorane, 1,2-benz-6
-ethylaminofluorane, etc.

Examples of compounds having a phenolic hydroxyl group include polyphenols such as mono-7-ethyls, and further substituents thereof include alkyl groups, aryl groups, acyl groups, alkyl dicarbonyl groups, and halogens. Examples of these compounds are shown below.

Tertiary-butylphenol, /nylphenol, dodecylphenol, α-su7tol, β-naphthol,
Hydroquinone more methyl ether, p-chlorophenol, p-bromophenol, 0-chlorophenol,
0-bromophenol, 〇-phenylphenol, 1)
-Phenyl7er7-yl, p-oxy1. Chill aromatic acid, 3
-isopropylcatechol, 1)-tert-butylcatechol, 4.4'-methylene diphenyl, bisphenol A, 1.2-dioxynaphthalene, 2.3-:)
Oxynaphthalene, chlorophenol, promocatefur, 2,4-dihydroxybenzo-7-ene/ene, 7-ethyl-7-thalein, methyl gallate, ethyl gallate, propyl gallate, butyl gallate, bexyl gallate, gallic acid. Examples include octyl gallate, dodecyl gallate, cetyl gallate, stearyl gallate, tannic acid, and phenolic resin.

Inorganic solid acids include silica-alumina, silica-magnesia, bentonite, kaolin, 7-raz anise, acid clay, activated clay, montmorillonite, attapulite, zinc oxide, titanium oxide, calcium sulfate, barium sulfate, aluminum sulfate, and aluminum chloride. , lead chloride, tin chloride, arsenic dioxide, etc.

Examples of organic acids include acetic acid, propionic acid, butyric acid, and caproic acid.

As the iron compound, ferric stearate, ferric myristate, ferric oleate, etc. are used.

Examples of the polyhydric aromatic acid having a phenolic hydroxyl group or its ester include gallic acid, tannic acid, methyl gallate, ethyl gallate, propyl gallate, butyl gallate, octyl gallate, dodecyl gallate, and stearyl gallate. and so on.

As the wax-like substance (2), a substance that melts at a temperature higher than a predetermined temperature and is basically inert to the above-mentioned color former (1) and color change agent (3) is used. The predetermined temperature refers to the maximum temperature at which the test object (for example, frozen food) must be stored at a low temperature.For example, in the case of a temperature instruction sheet for a test object that must be stored at a temperature lower than 20℃. The predetermined temperature is 20°C. This temperature depends on the type of specimen and the required storage temperature 1), and the wax-like substance may be arbitrarily selected depending on the temperature.

It is usually stored at 5 to 20°C, particularly around 10°C or lower, and is selected from substances having a melting point within that range.

Of course, this temperature is not limiting.

Examples of waxy substances used in the present invention include pentadecane, tetradecane, hexadecane, 1-
Aliphatic hydrocarbons such as heptadecane, ■-octadecane,
Aromatic hydrocarbon compounds such as p-xylene and dodecylbenzene, tricaprine glyceride, 1-elide-2,3
-Cicapurin glyceride, 1-lyl, j-2,3-laurin glyceride, 2-lino-1,3-dilaurin glyceride, 1-myrist-2,3-diolein glyceride, 1-palmito-2,3- Diolein glyceride, ethyl myristate, esters such as pentadecyl acetate, alcohols such as 2-undecanol, glycerol, halogenated hydrocarbons such as tribromoethane, dibromoethane, monoethanolamine, ethylenediamine, etc. Examples include amines, organic carboxylic acids such as formic acid and acetic acid, and ethers such as benzyl ether and dioxane.

These waxy substances should be appropriately selected depending on the type and combination of the color former and color change agent, the form of the temperature indicator sheet, etc.

For example, if a leuco dye is used as the color former (1), an organic carboxylic acid is used as the color change agent (3), and an alcohol such as 2-undecanol or glycerol is used as the waxy substance, color development is suppressed. , $1
As shown in the figures and FIG. 2, it is not preferable to use the mackerel mode. On the contrary, these alcohols are effective in decolorizing the substance (B) colored by leuco dye and organic carboxylic acid, so
It is useful for use in the embodiment shown in FIG.

In the final embodiment shown in FIG. 3, when a coloring layer of a leuco dye and an organic carboxylic acid is used as the substance (B), the component (A
As described above, the wax-like substance may have a color erasing effect per se, but other compounds having a color erasing effect may also be blended therein.

Examples of these compounds having a color erasing action include alcohols, esters, ketones, ethers, and aromatic hydrocarbons as illustrated below.

Alcohols include monohydric alcohols, polyhydric alcohols, and derivatives thereof. Examples of these compounds are shown below.

n-octyl alcohol, 11-nonyl alcohol,
n-decyl alcohol, 11-lauryl alcohol,
I+-myristyl alcohol, 0-cetyl alcohol,
Examples include low stearyl alcohol, oleyl alcohol, cyclohexalol, cyclopentanol, benzyl alcohol, cinnamyl alcohol, ethylene glycol, polyethylene glycol, propylene glycol, trimethylolpropane, pentaerythritol, and sorbitol.

Examples of compounds as Ethrels are shown below.

Amyl acetate, octyl acetate, butyl propionate, ethyl caproate, amyl caprylate, ethyl caprate,
Octyl caprate, lauryl caprate, methinoberaurate laurate, lauryl laurate, methyl myristate, hexyl myristate, stearyl myristate, butyl balmitate, myristyl balmitate, methyl stearate, ethyl stearate, lauryl stearate, Butyl benzoate, amyl benzoate, phenyl benzoate, ethyl acetoacetate, methyl oleate, butyl acrylate, dibutyl oxalate, diethyl malonate, dibutyl tartrate, dimethyl sepatate, dibutyl heptatalate, dioctyl heptatalate, 7 Dibutyl malate, diethyl maleate, triethyl citrate, 12-
Examples include hydroxystearic acid triglyceride, castor oil, dioxystearic acid methyl ester, and 12-hydroxystearic acid methyl ester.

The following compounds are exemplified as ketones.

Diethyl ketone, ethyl butyl ketone, methylhexyl ketone, mesityl oxide, cyclohexanone, methylcyclohexanone, acetophenone, benzophenone,
Examples include acetonyl acetone and diacetin alcohol.

The following compounds are exemplified as ethers.

Examples 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.

Aromatic hydrocarbons include p-xylene, isopropylbenzene, amylbenzene, mesinalene, cymene, 5
-Methyl-3-isobutyltoluene, dodecylbenzene, cyclohexylbenzene, biphenyl, methylbiphenyl, ethylbiphenyl, diethylbiphenyl, tri,
Ethyl biphenyl, benzylbenzene, phenyltolylmethane, xylylphenyl metabezitolylmethane, trioctylnophenylmethane, tribenzyldiphenylmethane, tolylxylylmethane, dixylylmethane, diphenylethane, tolylphenylethane, diphenylethane, phenylisopropylphenylethane, Tolyldiisopropylphenylethane, trimethylisopropylphenylethane, diphenylpropane, ditolylpropane, phenyltolylpropane, phenyltolylpropane
Tolylxylylpropane, dibenzylbenzene, dioctylbenzylethylbenzene, dibenzyltoluene,
Examples include tetrahydronaphthylphenylmethane, tetrahydromethylna7thylphenylethane, tetrahydronaphthylphenylethane, naphthylphenylmethane, and 7thylphenylethane.

Furthermore, a part of the compound group of substance (B) can be present in the layer of component (A) within a range that does not interfere with discoloration behavior. For example, component (l\) is alcohol, substance (B
) is a combination of an electron-donating color-forming organic compound and a solid inorganic acid.
>, and the layer of substance (B) may be made of only the solid inorganic acid.

The diffusion-permeable diaphragm (5) may be one that allows the component (A) that melts at a predetermined temperature to pass therethrough and come into contact with the substance (B) when it melts, such as paper, plastic film, An appropriate material such as men woven material may be used. At that time, in order to appropriately control the passage time of the molten material, the size, density, and thickness of the hole should be appropriately controlled.
The permeation rate may be controlled by treating with a suitable treatment agent such as silicon or the like.

Next, as the microencapsulation technology used in the present invention, the well-known coacervation method + in
A 5-itu polymerization method, an interfacial polymerization method, an underwater curing coating method, a phase separation method from an aqueous solution, a phase separation method from an organic solution, etc. can be used arbitrarily.

The method for applying microcapsules containing component (A) onto the diaphragm containing substance (B) is as follows: Knife coater 5 Brush coat 9-
, 1) There are bar roll coaters, bar footers, air knife coaters, etc., but an air knife coater is preferable in order to prevent the microcapsules from being destroyed during coating. The method for destroying the microcapsules containing component (A) during use of the sheet is not particularly limited, but may include exposing the entire system to a temperature not lower than a predetermined temperature, depending on the time and temperature in this case. In order to understand the changes, it is desirable to break it under a constant load using a hand roller.

The microcapsules have a size of about 1 to 300 μm so that they can be easily broken with a roller or the like during use.

If it is less than 1 μm, it is difficult to break, and if it is more than 300 μm, the particle size is large and causes problems in the coating process.

The film-forming ingredients used in microcapsules are gelatin,
These include alginic acid, acrylic polymers, methacrylic polymers, melamine, and epoxy polymers, and these are easily destroyed by external force at low temperatures.

A substance (A) that melts at a predetermined temperature and a substance (B) that changes color upon contact with the substance (A) are usually applied onto the diaphragm by appropriate means. This may be adhered to the diaphragm with a suitable coating film-forming component, such as a water-soluble resin such as POVAL, or an adhesive component, such as an acrylic acid ester copolymer main, or the whole may be backed with a transparent film or the like. It can also be used as a label.

An example of the temperature indicator sheet of the present invention is schematically shown in FIG.

The temperature indicator sheet F in Fig. 4 has a white base paper (6) placed on the bottom surface of the basic component shown in Fig. 1 to make discoloration clear.
Total Zero is covered with a transparent plastic film (7) and further coated with an adhesive layer (8).

In addition, additives may be added to the component (A), the substance (B), and the diaphragm to improve necessary conditions, to the extent that they do not interfere with the irreversible discoloration of the substance (B), which is the object of the present invention. Take it. Typical such additives are:
Antioxidant, UV absorber.

These include inorganic fillers, pigments, plasticizers, lubricants, antistatic agents, etc.

Methods for attaching the temperature instruction sheet of the present invention to products stored at low temperatures include attaching it with an adhesive, hanging it as a label,
Examples include direct adhesion to containers for cryogenic storage.

Preferred examples for which the temperature indication sheet of the present invention can be used include, but are not limited to, kamaboko, raw noodles, yogurt, night pickles, and packaged sushi.

Next, specific examples will be shown, but the present invention is not limited thereto.

Example I 20 g of dimethylazibe in which CV L (crystal violet lactone) was dissolved was mixed with 100 g of a 5% aqueous gelatin solution, heated to 50° C., and stirred to form minute oil droplets. Next, carboxymethyl cellulose (C
MC) 7 parts of a 5% aqueous solution were added. After the pH was lowered by 4.81 degrees, the entire system was cooled to 4-5 degrees Celsius. 37% formalin was added and hardened.

The pH was raised to 10.0, and the temperature was gradually raised to 50°C in 2 hours. The desired microcapsules were obtained.

The obtained capsules are processed by filtration, centrifugal concentration, drying,
Alternatively, it can be used in its raw form, but in this example, it was filtered and used in the form of a cake.

The same applies to the following examples.

Example 2 20g of a mixture of nonylphenol and bentadecane, 10g of methyl methacrylate, and 50+nB of azobisisobutyronitrile were uniformly dissolved. This was dispersed in 100 g of 0.5% methyl cellulose solution to form minute oil droplets. Thereafter, the reaction was carried out at 75°C for 5 hours to obtain the desired microcapsules.

Example 3 After dissolving sodium alginate 2Fh gelatin IC in 150 ml of water, 50 g of ethyl myristate was added dropwise and stirred until minute oil droplets were formed. Separately, 500 g of a 10% calcium chloride aqueous solution was prepared and the dispersion liquid was dropped into this, and the sodium alginate was hardened and the desired microcapsules were obtained.

Example 4 4 g of terephthalic acid dichloride and 50 g of acetophenone
and bisphenol A5. Add to a 1% aqueous solution of 7 um hydroxide and stir until fine oil droplets form. After reacting at 50°C for 2 hours, the desired microcapsules were obtained.

Example 5 1.5 g of Neelamine P-6300 (Mitsui Toatsu, methoxymethylolmelamine) was dissolved in 1508 ml of water, 508 ml of a mixture of lauryl alcohol-11-pentadecane was added, and the mixture was stirred until it became minute oil droplets. After this, when r+H was adjusted to 4 to 5 and reacted at 50°C for 5 hours,
Microcapsules coated with the desired melamine resin were obtained.

Example 6 5g of two Pifu) 828 (shell, epoxy resin) and 1
]-xylene was mixed. This mixture was mixed with 0°5% CMC.
After dispersing in 200 g of an aqueous solution, a curing agent was gradually added dropwise and the mixture was reacted at 80° C. for 5 hours to obtain the desired microcapsules.

Example 7 Activated clay was dispersed in a poval aqueous solution and uniformly coated on the surface of a high-quality paper. On the back side, the microcapsule cake prepared in Example 1 was dispersed in an aqueous cinnabar solution and coated with a bar coater to a coating layer of 60 μm. After drying thoroughly, divide the test paper into two equal parts, and both weigh (I Kg/ (0,05c)
Destroy the microcapsules by applying a load of about qo2)-+20KB/ca1121, and leave one side at room temperature (a:
The IQ side was stored at low temperature (15°C) and the change in color tone was observed. In (a), color development started immediately and the color was saturated in about 30 minutes. No discoloration was observed in (1)). (
1) After one week had passed, the sample immediately started to change color when it was left at room temperature again.

Examples 8 to 22 Experiments similar to those in Example 7 were conducted by changing the materials used. The results are listed in the table. Here, (A) is a microencapsulated substance, the substance in parentheses is a dissolved waxy substance, and (B) is a dark blue substance that changes color when it comes into contact with (A). (C) shows the diaphragm at the boundary, and the thickness is shown in parentheses.

(D) is the discoloration and the discoloration starting temperature and time.

[Brief explanation of drawings]

FIGS. 1 to 3 are schematic diagrams showing the basic configuration of the temperature indication sheet of the present invention, and FIG. 4 is a schematic diagram of one embodiment of the specific configuration. In the figure, (1) is a coloring agent, (2) is a waxy substance, and (3
) indicates a color change agent, (4) indicates a microcapsule, and (5) indicates a diaphragm. Procedural amendment (voluntary) April 1982 6) b. Commissioner of the Japan Patent Office 1. Indication of the case Patent Application No. 163754 of 1988 2. Name of the invention Representative Gobe Kimura 4. Agent 6. Subject of amendment ``Detailed Description of the Invention'' column of the specification (1)
1 Specification, page 5, lines 11-12, “The inventors of wood...
・・・－・－・・・・・・It was proposed, but the entire sentence is corrected to ``Temperature indicator labels that change color after a certain period of time at a certain temperature have also been proposed.''that's all

Claims (1)

[Claims] 1. (i) Component (A) that melts at a predetermined temperature (ii) Substance (B) that causes discoloration upon contact with component (A) (i'ii)
Component (A) has a diaphragm through which the molten component (A) can pass.
is encapsulated in microcapsules that can be broken by external pressure at the operating temperature, and the component (A) and substance (B) are placed on opposite sides with a diaphragm interposed therebetween. 2. The component ()\) that melts at a predetermined temperature contains a color former (1) and a waxy substance (2), and the substance (B) contains the color change agent ().
3) The temperature instruction sheet described in item 1. 3. The component (A) that melts at a predetermined temperature contains a color change agent (3) and a waxy substance (2), and the substance (B) is a color former (1).
The temperature instruction sheet according to item 1, which includes: 4. Substance (B) contains a substance colored by a coloring agent (1) and a color change agent (3), and component (A) contains a waxy substance (2) and a component that decolorizes the colored substance. Temperature instruction sheet described in item 1. 5. Items 2 to 4 in which the coloring agent (1) is a compound with electron-donating color forming properties, and the color changing agent (3) is a compound having a phenolic hydroxyl group, an organic carboxylic acid, or an inorganic solid acid. Temperature instruction sheet according to any one of the following. 6. The color former (1) is an iron compound, and the color change agent (3) is a metal compound/-
The temperature indicator sheet according to any one of items 2 to 4, which is a polyvalent human oxygen compound having a basic hydroxyl group. 7. The wax-like substance has a melting point of 20'C or less, including higher alcohols, polyhydric alcohols, esters, polyalkylene glycols, hydrocarbons, ethers, halogenated hydrocarbons, amines, and polycarboxylic acids. Temperature instruction sheet according to any one of items 2 to 4 selected from the group. 8. Microcapsules are gelatin, alginic acid, acrylic resin, methacrylic resin, melamine, epoxy type 1
The temperature indication sheet according to any of the preceding items, which contains j1 fat as a film component. 9. The temperature indication sheet according to any one of the preceding items, wherein the microcapsules have a size of 1 to 30 ()μ. 10. The temperature indicating sheet according to any of the preceding items, wherein the diaphragm is selected from paper, plastic film, and nonwoven fabric.