JP5769835B2 - High temperature irreversible temperature control material - Google Patents

Description

  The present invention relates to a high temperature irreversible temperature control material that irreversibly discolors at a high temperature of 300 ° C. or higher.

  A temperature control material having a temperature-sensitive color-changing layer that changes color at a predetermined temperature is attached to a product such as processed food that is heat-treated, the temperature-sensitive color-changing layer is inspected after the heat treatment, and the product is heated to a predetermined temperature. It is checked whether the product has been sufficiently sterilized or whether the product has been heated to a predetermined temperature or higher and the product has not been thermally deteriorated to assure the quality of the product after the heat treatment (for example, Patent Document 1 and Patent Document 2). In the temperature-sensitive discoloration layer of these temperature control materials, discoloration occurs when the hot-melt material melted at a predetermined temperature is absorbed by the paper base material, but the paper base material withstands high temperatures of 300 ° C. or higher. I can't. For this reason, these temperature control materials cannot be used for high-temperature heat treatment at 300 ° C. or higher.

  By the way, as a temperature control material that can be used in a high-temperature heat treatment at 300 ° C. or higher, Patent Document 3 and Patent Document 4 include an irreversible temperature control material in which a temperature-sensitive color former containing a heavy metal such as cobalt or nickel is formed. Have been described. Furthermore, in Patent Document 3, a temperature control material mounted on a material such as a wafer is used as a heat-resistant resin film or a heat-resistant material in order to prevent the heavy metal of the temperature-sensitive color former from being diffused as a gas during heat treatment. Coating with a conductive resin layer is described. Further, in Cited Document 4, a temperature control material attached to one side of a transparent or translucent material is coated with a fouling film that prevents gasification of heavy metals in the temperature-sensitive color former, It is described that the discoloration is known from the other side of the material.

JP 2003-172661 A JP 2005-291825 A JP 2007-57337 A JP 2008-270586 A

  According to the irreversible temperature control material in which the temperature-sensitive color former containing heavy metals such as cobalt and nickel of Patent Document 3 and Patent Document 4 is formed, the heating temperature of the material subjected to the high-temperature heat treatment exceeding 150 ° C. I can know. However, in order to cover the temperature control material attached to the material with a heat resistant resin film or a heat resistant resin layer as in Patent Document 3, the heat resistance can maintain transparency or translucency in a high temperature atmosphere of 300 ° C. or higher. However, the resin having such heat resistance is limited. Further, as described in Patent Document 4, it is transparent or semi-transparent to coat a temperature control material adhered to one side of a transparent or translucent material with an anti-fouling film that prevents gasification of heavy metals in the thermosensitive color former. It can only be applied to transparent materials and limits the material to be heated. Furthermore, it is necessary to coat the temperature control material attached to the heated material with a heat-resistant resin film or heat-resistant resin layer, or with an anti-fouling film. It is an extremely complicated task.

  The present invention has been made to solve the above-described problems, and includes a temperature-sensitive color-changing layer that does not need to be coated with a heat-resistant resin or an anti-fouling film and that irreversibly changes color at a high temperature of 300 ° C. at least. It aims at providing a high temperature irreversible temperature control material.

The irreversible temperature control material for high temperature made to achieve the above-mentioned object is a material that does not contain heavy metals and is irreversibly discolored at a detection temperature of at least 300 ° C. on at least a part of one side of the metal foil. A temperature control material in which a temperature-changing layer is formed, wherein the temperature-sensitive color-changing layer is a pressure-sensitive adhesive containing an organic acid light metal salt that melts, sublimates or decomposes at a temperature of at least 300 ° C. It is bonded to one surface of the foil, and the specific gravity of the light metal in the light metal salt of the organic acid is 4 at the maximum, and the cellulose component is decomposed or disappears at a temperature of 300 ° C. at the minimum .

  The light metal salt of the organic acid is preferably an alkali metal salt of aromatic carboxylic acid or aromatic sulfonic acid.

  The light metal salt of the organic acid is preferably an aromatic carboxylic acid or an aromatic sulfonic acid sodium salt or potassium salt.

It is preferable that the temperature-sensitive discoloration layer is not covered with a heat-resistant resin film, a heat-resistant resin layer, or a fender .

  The metal foil is preferably an aluminum foil or a stainless steel foil.

  It is preferable that a coating material having a color different from that of the temperature-sensitive discoloration layer is applied to the surface of one surface of the metal foil.

  It is preferable that an adhesive layer containing a silicone component is formed on the other side of the metal foil.

  According to the irreversible temperature control material for high temperature according to the present invention, the temperature-sensitive discoloration layer is discolored at a high temperature of 300 ° C. or more exceeding 150 ° C. without containing heavy metals. The possibility of contaminating the inside of the chamber where the heat treatment body is heat-treated at 300 ° C. or higher without being covered with a fender or the like with heavy metals can be eliminated. Moreover, the measurement of the presence or absence of the heating temperature spot etc. of the heat processing body which heat-processed at the high temperature of 300 degreeC or more, and the heat processing log | history of a heat processing body can be managed, and it can be used for quality control of a heat processing body.

  Hereinafter, modes for carrying out the present invention will be described in detail, but the scope of the present invention is not limited to these modes.

  In the irreversible temperature control material for high temperature according to the present invention, a temperature-sensitive color-changing layer that does not contain heavy metal and irreversibly changes color at a detection temperature of at least 300 ° C. is formed on at least a part of one side of the metal foil. In this temperature-sensitive color changing layer, a light metal salt of an organic acid that melts, sublimates or decomposes at a temperature of at least 300 ° C. is bonded to one side of the metal foil with an adhesive.

  The heavy metal referred to in the present invention refers to a metal having a specific gravity exceeding 4, and specifically refers to a metal excluding alkali metals and alkaline earth metals. In addition, the metal foil does not melt at a detection temperature as high as 300 ° C. or higher as compared with the resin film, and has good heat conductivity, and the heat-sensitive color change layer on one side has heat on the other side. Can transfer heat quickly. As this metal foil, any metal foil may be used as long as it does not melt at a detection temperature of 300 ° C. or higher, and an aluminum foil or stainless steel foil that is stable without being discolored even when heated at a detection temperature of 300 ° C. or higher is preferably used. Can be used.

  In the temperature-sensitive discoloration layer formed on one side of such a metal foil, a light metal salt of an organic acid that melts, sublimes or decomposes at a temperature of at least 300 ° C. is fixed to the one side of the metal foil with an adhesive. . Here, the light metal has a specific gravity of 4 or less, and specifically refers to a metal belonging to an alkali metal or an alkaline earth metal. In addition, light metal salts of organic acids that melt, sublimate or decompose at a temperature of at least 300 ° C. have a sublimation or decomposition temperature of at least 300 ° C. or do not melt even if the melting point is less than 300 ° C. Includes those that sublime or decompose at least at 300 ° C.

  Examples of light metal salts of organic acids that melt, sublimate or decompose at a temperature of at least 300 ° C. include alkali metal salts of aromatic carboxylic acids such as disodium terephthalate, potassium benzoate, sodium salicylate, sodium isonicotinate; sulfanilic acid Examples include alkali metal salts of aromatic sulfonic acids such as sodium and sodium benzenesulfonate; alkali metal salts of oxopropanoic acid such as sodium pyruvate. Among these light metal salts of organic acids, sodium or potassium salts of aromatic carboxylic acids such as disodium terephthalate, potassium benzoate, sodium salicylate, sodium isonicotinate, or sodium sulfanilate, sodium benzenesulfonate A sodium salt or potassium salt of an aromatic sulfonic acid such as

  Such a light metal salt of an organic acid that melts, sublimes or decomposes at a temperature of at least 300 ° C. is adhered to an adhesive material on one side of the metal foil to form a temperature-sensitive color changing layer. The temperature-sensitive discoloration layer may be formed on the entire surface of one side of the metal foil, or may be formed on a part of the one side of the metal foil. When forming a temperature-sensitive color-changing layer on a part of one side of the metal foil, the temperature-sensitive color-changing layer must be coated on the surface of the metal foil with a color different from that of the temperature-sensitive color-changing layer. It is preferable because it can be confirmed visually whether the color has changed. As the paint, a heat resistant paint blended with a silicone resin is preferable.

  As the adhesive material used for the temperature-sensitive discoloration layer, a heat-resistant adhesive material mainly composed of a silicone component such as an organosilopolysiloxane may be used, but the heat resistance is inferior compared to an adhesive material containing a silicone component. An adhesive material containing a cellulose component can be suitably used. When the temperature-sensitive discoloration layer is discolored due to decomposition of the light metal salt of the organic acid at a high temperature of 300 ° C. or higher, the discoloration can be clearly recognized as compared with the adhesive material containing a silicone component. This is probably because the cellulose component-containing pressure-sensitive adhesive material decomposes and disappears at a high temperature of 300 ° C. or higher. Examples of the cellulose component-containing pressure-sensitive adhesive material include ethyl cellulose and methyl cellulose.

  An irreversible temperature control material for high temperature having a temperature-sensitive discoloration layer formed on one side of a metal foil is placed on a heat treatment body subjected to a high temperature heat treatment at 300 ° C. or higher, and is subjected to a predetermined heat treatment together with the heat treatment body. The During the heat treatment, it is preferable that a heat-resistant adhesive layer containing a silicone component is formed on the other side of the metal foil so that the irreversible temperature control material for high temperature is surely located at a predetermined position of the heat treatment body. .

  When the heating temperature reaches a detection temperature of 300 ° C. or higher, the light metal salt of the organic acid in the temperature-sensitive color changing layer is melted when the heating temperature reaches a detection temperature of 300 ° C. or higher. Sublimation or decomposition causes discoloration, and the temperature-sensitive discoloration layer discolors. The discolored temperature-sensitive discoloration layer does not return to its original state even when the irreversible temperature control material for high temperature is cooled to room temperature. According to such a high temperature irreversible temperature control material, the presence or absence of discoloration of the temperature-sensitive discoloration layer of the high temperature irreversible temperature control material placed on the heat-treated body cooled after the heat treatment is visually confirmed. Thus, it can be determined whether or not the heat treatment body has been heated to a heat treatment temperature of 300 ° C. or higher, or whether or not the heat treatment body has been heated to a temperature higher than 300 ° C. This temperature-sensitive discoloration layer is colorless when the light metal salt of the organic acid is sublimated and discolored, making the color tone of the metal foil visible, and when the light metal salt of the organic acid is discolored and discolored, brown To black. Furthermore, the temperature-sensitive discoloration layer of the irreversible temperature control material for high temperatures does not contain heavy metal, and the possibility of contamination of the inside of the chamber for heating the heat-treated body with heavy metal can be eliminated.

  Such an irreversible temperature control material for high temperature is obtained by kneading a light metal salt of an organic acid that melts, sublimates or decomposes at a temperature of at least 300 ° C., an adhesive, and a solvent with a kneader such as a ball mill. The temperature-sensitive color change layer can be obtained by drying the formed temperature-sensitive color change layer after applying the temperature indicating ink to at least a part of one side of the metal foil as a printing substrate by screen printing or the like to form the temperature-sensitive color change layer. . By applying a heat-resistant paint having a color different from that of the temperature-sensitive color changing layer to be formed on the surface of one surface of the metal foil, the color change of the temperature-sensitive color changing layer can be easily visually confirmed. Further, a heat-resistant adhesive containing a silicone component may be applied to the other side of the metal foil to form an adhesive layer so that it can be adhered to a predetermined position of the heat treatment body.

  Examples of the present invention will be described in detail below, but the scope of the present invention is not limited to these examples.

Example 1
(1) Preparation of high temperature indicating ink 50 g of dinatrim terephthalate, which is a light metal salt of an organic acid, 2 g of ethyl cellulose, which is an adhesive, and 48 g of hexanol, which is a solvent, are kneaded in a ball mill for three days to obtain a high temperature indicating ink. It was.
(2) Preparation of printing substrate HP-350N manufactured by YS Tech Co., Ltd. was prepared as a printing substrate. In this printing substrate, a black heat-resistant paint is applied to the entire surface of one surface of the stainless steel foil, and a heat-resistant adhesive containing a silicone component is applied to the other surface to form an adhesive layer.
(3) Production of irreversible temperature control material for high temperature Feeling formed by applying the temperature indicating ink for high temperature obtained in (1) by screen printing on the one side of the printed substrate on which the black heat-resistant paint is applied After drying the thermochromic layer, it was cut into a 5 mm × 5 mm square to obtain an irreversible temperature control material for high temperature. The temperature-sensitive discoloration layer of the obtained irreversible temperature control material for high temperature was white.
(4) Discoloration temperature of temperature-sensitive discoloration layer The obtained high temperature irreversible temperature control material was attached to a stainless steel plate with an adhesive layer formed on the other surface side of the stainless steel foil, and then inserted into the muffle furnace together with the stainless steel plate. Next, the temperature inside the muffle furnace was increased at a temperature increase rate of 2.5 ° C./min, and the color change temperature at which the temperature-sensitive color change layer changed to black was measured. The discoloration temperature was measured 10 times and the average temperature was determined to be 600 ° C.
(5) Recoloring test The stainless steel plate with the high temperature irreversible temperature control material with the temperature-sensitive discoloration layer changed to black was taken out of the muffle furnace, cooled to room temperature, and the temperature-sensitive discoloration layer changed to black turned white. It was confirmed whether or not the color was restored. The temperature-sensitive discoloration layer of the cooled high temperature irreversible temperature control material was still black and no recoloring was observed. It is inferred that dinatrim terephthalate was decomposed at 600 ° C. without melting to discolor the temperature-sensitive discoloration layer to black.

(Example 2)
An irreversible temperature control material for high temperature was prepared in the same manner as in Example 1 except that dinatrim terephthalate, which is a light metal salt of an organic acid, was replaced with the one shown in Table 1 below. About the obtained irreversible temperature control material for high temperature, the discoloration temperature of the thermosensitive color-change layer was measured like Example 1, and the recoloring test was done. The measured discoloration temperature, the hue of the temperature-sensitive discoloration layer after discoloration, and the results of the color recovery test are also shown in Table 1 below.

  The discoloration temperature of the temperature-sensitive discoloration layer containing sodium salicylate, which is a light metal salt of an organic acid described in Table 1, is 540 ° C. Although the melting point of sodium salicylate is 200 ° C., it is presumed that the temperature-sensitive discoloration layer was discolored to black by decomposition at the discoloration temperature of 540 ° C. The melting point of sodium benzenesulfonate is 450 ° C., but the color change temperature of the temperature-sensitive color changing layer is 400 ° C. It is considered that sodium benzenesulfonate is decomposed at a temperature lower than the melting point to discolor the temperature-sensitive discoloration layer to black. The melting points of sodium sulfanilate, sodium pyruvate, sodium isonicotinate, and potassium benzoate are all 300 ° C or higher, and the temperature-sensitive discoloration layer of any organic acid light metal salt is discolored at a temperature higher than the melting point. Therefore, it is inferred that the temperature-sensitive discoloration layer has been disassembled and discolored.

  The irreversible temperature control material for high temperature according to the present invention is capable of managing the measurement of the presence or absence of heating temperature spots of a heat treatment body subjected to heat treatment at a high temperature of 300 ° C. or higher and the heat treatment history of the heat treatment body, and the quality control of the heat treatment body Can be used.

Claims (7)

A temperature control material in which a temperature-sensitive color-changing layer that does not contain heavy metal and irreversibly changes color at a detection temperature of at least 300 ° C. is formed on at least a part of one side of the metal foil,
The temperature-sensitive discoloration layer has a light metal salt of an organic acid that melts, sublimates or decomposes at a temperature of at least 300 ° C., and is adhered to one side of the metal foil with an adhesive material containing a cellulose component ,
The specific gravity of the light metal in the light metal salt of the organic acid is at most 4,
An irreversible temperature control material for high temperature, wherein the cellulose component decomposes or disappears at a temperature of at least 300 ° C.   The irreversible temperature control material for high temperature according to claim 1, wherein the light metal salt of the organic acid is an aromatic metal salt of an aromatic carboxylic acid or an aromatic sulfonic acid.   The irreversible temperature control material for high temperature according to claim 1, wherein the light metal salt of the organic acid is a sodium salt or a potassium salt of an aromatic carboxylic acid or an aromatic sulfonic acid. 2. The irreversible temperature control material for high temperature according to claim 1, wherein the temperature-sensitive color-changing layer is not covered with a heat-resistant resin film, a heat-resistant resin layer, or an anti-mold film.   The irreversible temperature control material for high temperature according to claim 1, wherein the metal foil is an aluminum foil or a stainless steel foil.   2. The irreversible temperature control material for high temperature according to claim 1, wherein a coating material having a color different from that of the temperature-sensitive discoloration layer is applied to a surface on one side of the metal foil.   The irreversible temperature control material for high temperature according to claim 1, wherein an adhesive layer containing a silicone component is formed on the other surface side of the metal foil.