JPH0583136B2 - - Google Patents

Description

(iv) a diaphragm 7; (v) a binder 6; (vi) a waterproofing agent 8; 1 and a color former 2 or a wax-like substance 1 and a color change agent 3 are encapsulated so that they can be destroyed by external pressure, and the color former 2 is contained on the opposite side from the color change agent 3 through a diaphragm 7, making it waterproof. A temperature-indicating label in which an agent 8 is contained on the side opposite to the wax-like substance 1 with a diaphragm 7 interposed therebetween, and the wax-like substance 1, coloring agent 2 and color-changing agent 3 are applied on the same side as the layer 5 via a binder. 2. The temperature-indicating label according to item 1, wherein the water-resistant agent 8 is selected from compounds having water repellency.

[Detailed description of the invention]

FIELD OF INDUSTRIAL APPLICATION The present invention relates to a temperature indicator label with improved water resistance. BACKGROUND ART Products stored at low temperatures, such as frozen foods, usually change in quality once they are exposed to an environment above a predetermined temperature, but if the deteriorated food is stored at a low temperature again, it may become indistinguishable from the unaltered product 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 that. When exposed to temperatures higher than the specified temperature during temperature control for general low-temperature storage products (0°C to 20°C),
Temperature instruction sheets that change color depending on the temperature and time have been proposed (Japanese Patent Application Laid-open Nos. 188529-1988 and 55235-1980). Problems to be Solved by the Invention The temperature indicating label disclosed in the above invention is manufactured and stored in such a way that the color forming agent and the color changing agent do not come into contact with each other. are often exposed to. At that time, a phenomenon may be observed where the colored parts exposed to high temperatures fade due to humidity and moisture. Furthermore, if a temperature indication label is stamped in a high temperature environment, coloring will begin immediately, so stamping must be done at a temperature below the coloring temperature, which is inconvenient in actual use. That is, an object of the present invention is to provide a temperature-indicating label whose colored portion does not fade during use after manufacturing the temperature-indicating label. Another object of the present invention is to provide a temperature instruction sheet whose time from stamping to storage at a low temperature is delayed in a high temperature environment. Means for Solving the Problems The present inventors have discovered that the above-mentioned discoloration of the temperature indicator label during use can be resolved by using a water-resistant agent. That is, the present invention comprises: (i) a wax-like substance 1 that melts at a predetermined temperature; (ii) a color former 2; (iii) a color change agent 3 that changes color upon contact with the color former 2; (iv) a diaphragm 7 ( v) a binder 6; (vi) a waterproofing agent 8; and (vii) a layer 5 that does not transmit the molten wax-like substance 1, the color former 2, and the color change agent 3; A wax-like substance 1 and a color change agent 3 are encapsulated so as to be destructible by external pressure, a color forming agent 2 is contained on the side opposite to the color change agent 3 through a diaphragm 7, and a water resistance agent is contained through a diaphragm 7. The present invention relates to a temperature-indicating label in which the wax-like substance 1, the coloring agent 2, and the color-changing agent 3 are applied on the same side as the layer 5 via a binder. In the present invention, a temperature-indicating label refers to a label that develops color when exposed to a temperature higher than a predetermined temperature. A schematic diagram of a part of the basic structure of the temperature indicator label of the present invention will be explained based on FIGS. 1 to 5. In FIG. 1, a wax-like substance 1 that is encapsulated on a layer 5 and melts at a predetermined temperature and an encapsulated coloring agent 2 are applied to a diaphragm 7 against a color-changing agent 3 and a waterproofing agent 8.
It shows how it is bound with a binder 6 on the side opposite to the layer containing it. In this specification, wax-like substance 1 refers to a substance that exhibits a wax-like appearance at the operating temperature, that is, when this label is attached to a low-temperature storage product, etc., and is a substance that exhibits a wax-like appearance at room temperature. It doesn't mean anything. The feature of the present invention is to take advantage of the fact that when the waterproofing agent 8 is contained on the opposite side of the wax-like substance 1 to the diaphragm 7, the color once developed will not fade. Temperature-indicating labels take a long time (hereinafter referred to as the "grace time") until the capsule develops color even if the capsule is destroyed in an environment above the operating temperature. That is, before coloring occurs, the encapsulated wax-like substance 1 and the encapsulated color-forming agent 2 are destroyed by stamping, and the molten wax-like substance 1 diffuses into the binder 6 to form the color-forming agent 2 or the encapsulated color-forming agent 2. Upon contact with the color-changing agent 3, the melted wax-like substance 1 diffuses into the binder 6 together with the color-forming agent or the color-changing agent 3, further diffuses through the diaphragm 7, diffuses into the binder 6 again, and forms the color-forming agent 2 and the color-changing agent 3. Each step of contact with the color change agent 3 is required. Therefore, it is possible to perform stamping work in an environment at a predetermined temperature or higher, and it is only necessary to cool down within a grace period, which is very convenient for use. The temperature label is cooled to a predetermined temperature or lower within the grace period, and the above-described process is interrupted before the molten wax-like substance becomes wax-like and develops color. When the temperature of the temperature indication sheet affixed to a low-temperature-preserved product reaches a predetermined temperature or higher, the wax-like substance melts again, and the interrupted process starts again, resulting in color development. Before or after attaching a label to a product stored at low temperature, pressure is applied to the sheet using an appropriate method such as a roller or a stamp to destroy the microcapsules. For convenience, this destructive operation will hereinafter be referred to as "engraving." After stamping, the temperature-indicating label of the present invention is cooled to a predetermined temperature or lower within a grace period, and the above-described process is interrupted before the molten wax-like substance becomes wax-like and develops color. When the temperature of the temperature indication sheet affixed to a low-temperature-preserved product reaches a predetermined temperature or higher, the wax-like substance melts again, and the interrupted process starts again, resulting in color development. FIG. 2 is the same as FIG. 1 except that the layers containing the encapsulated wax-like material 1 and the waterproofing agent 8 have been replaced in FIG. The steps from engraving to color development are substantially the same as those described in FIG. FIG. 3 differs from FIG. 1 in that the color forming agent 2 is not encapsulated, but the color changing agent 3 is encapsulated. FIG. 4 differs from FIG. 2 in that the color change agent 3 is encapsulated instead of the color forming agent 2. Fig. 5 shows a wax-like substance 1 compared to Fig. 1.
A layer containing a color forming agent 2 and a layer containing a color changing agent 3 and a waterproofing agent 8 are laminated in reverse on layer 5. Examples of the water-repellent agent include compounds having water-repellent properties, such as silicone compounds such as straight silicone varnish and alkyd silicone varnish, and polymeric compounds such as water-repellent silica and organic benite. The water resistance agent is used in an amount of 5 to 20% by weight based on the color change agent. If it is less than 5% by weight, the water resistance will be poor, and if it is more than 20% by weight, the color development will be insufficient. Examples of combinations of color former 2 and color change agent 3 used in the present invention are as follows. (i) Electron-donating color-forming organic compound (color former) and acids (phenolic hydroxyl group-containing compound, organic carboxylic acid, inorganic solid acid, etc.) (color change agent) (ii) PH indicator (color former) and acid or alkali (Color change agent) (iii) Polyhydric hydroxy compound having an iron compound and a phenolic hydroxyl group Examples of the electron-donating color-forming organic compounds used in the present invention include diarylphthalides, polyarylcarbinols, and leucoauramines. , acylouramines, arylauramines, rhodamine beta-lactams, indolines, ipilopyrans,
There are fluorans, etc. Examples of these compounds are shown below. Crystal violet lactone, malachite green lactone, Michler hydrol, crystal violet carbinol, malachite green carbinol, N-(2,3-dichlorophenyl)leukouramine, N-benzoyluramine, N-acetyl auramine min, N-phenyluramine, rhodamine beta-lactam, 2-(phenyliminoethanedylidene)3,3-dimethylindoline, N-3,3-trimethylindolinobenzspiropyran, 8'-methoxy N-3, 3-trimethylindolinobenzspiropyran, 3-diethylamino-6-methyl-7-chlorofluorane, 3-diethylamino-7-methoxyfluorane, 3-diethylamino-6-benzyloxyfluorane, 1,2-benz-6- Examples include diethylamino-fluoran. As a compound having a phenolic hydroxyl group,
There are monophenols and polyphenols,
Furthermore, substituents thereof include an alkyl group, an aryl group, an acyl group, an alkoxycarbonyl group, and a halogen group. Examples of these compounds are shown below. Tertiary-butylphenol, nonylphenol, dodecylphenol, α-naphthol, β
- Naphthol, hydroquinone monomethyl ether, p-chlorophenol, p-bromophenol, o-phenylphenol, p-phenylphenol, methyl p-oxybenzoate, 3-isopropylcatechol, p-tertiarybutylcatechol, 4, 4'-methylene diphenyl, bisphenol A, 1,2-dioxynaphthalene, chlorcatechol, bromocatechol, 2,4-dihydroxybenzophenone, phenolphthalein,
Methyl gallate, ethyl gallate, propyl gallate, hexyl gallate, octyl gallate, dodecyl gallate, cetyl gallate, stearyl gallate, tannic acid, phenolic resin, salicylic acid, zinc salicylate, zinc t-butylsalicylate, etc. be. Examples of inorganic solid acids include silica-alumina, silica-magnesia, bentonite, kaolin, fuller's earth, acid clay, activated clay, montmorillonite, attapulgite, zinc oxide, titanium oxide,
These include calcium sulfate, barium sulfate, aluminum sulfate, aluminum chloride, lead chloride, tin chloride, and arsenic dioxide. Organic acids include acetic acid, propionic acid, butyric acid,
Such as caproic acid. As the iron compound, ferric stearate, ferric myristate, ferric oleate, etc. are used. Examples of the polyhydroxy aromatic acid having a phenolic hydroxyl group or its ester include gallic acid,
Tannic acid, methyl gallate, ethyl gallate,
Examples include propyl gallate, butyl gallate, octyl gallate, dodecyl gallate, and stearyl gallate. As the wax-like substance 1, a substance which melts at a temperature higher than a predetermined temperature and which is basically inactive with respect to the above-mentioned color former 2 and color change agent 3 is used.
The predetermined temperature refers to the highest temperature at which a test object (such as a low-temperature storage product) must be stored.For example, in the case of a temperature instruction sheet for a test object that must be kept at a temperature lower than 20℃, , the predetermined temperature is
It is 20℃. This temperature depends on the type of specimen and the required storage temperature, and the wax-like substance may be arbitrarily selected depending on the temperature. Usually 5~
It is often stored at 20°C, especially around 10°C or lower, and is selected from substances that have a melting point within that range. Of course, this temperature is not limiting. Examples of wax-like substances used in the present invention include aliphatic hydrocarbons such as pentadecane, tetradecane, hexadecane, 1-heptadecane, and 1-octadecane, aromatic hydrocarbon compounds such as p-xylene and dodecylbenzene, and tricapric acid. Ceride, 1-elide-2,3-dicaprine glyceride, 1-linoleo-2,3-lauryl glyceride, 2-oleo-1,3-dilauryl glyceride, 1-myrist-2,3-dio Esters such as rhein glyceride, 1-palmito-2,3-diolein glyceride, methyl myristate, ethyl myristate, butyl myristate, methyl palmitate, ethyl palmitate, methyl laurate, ethyl laurate, pentadecyl acetate, etc. , alcohols such as 2-undecanol and glycerol, halogen hydrocarbons such as tribromoethane and 1,2-dibromoethane, amines such as monoethanolamine and ethylenediamine, organic carboxylic acids such as formic acid and acetic acid, benzyl ether, dioxane, etc. Examples include ethers. The temperature-indicating label of the present invention is obtained by applying a solution obtained by appropriately mixing and dispersing the above-mentioned composition to a resin solution in which a binder resin is dissolved. Examples of the coating method include printing methods such as screen printing, gravure printing, and flexographic printing, a bar coater, an air knife coater, and a roll coater, but the method is not limited to these methods. The resin solution consists of a resin and a solvent for dissolving the resin, and the resin component includes acrylic resin,
Examples include methacrylic resin, urethane resin, rosin resin, and alkyd resin. Examples of solvents include hydrocarbon solvents such as mineral turpentine, ester solvents such as ethyl acetate and butyl acetate, alcohols with _C3 or more,
For example, isopropyl alcohol or the like can be used, but there is no particular restriction as long as it dissolves the resin component, does not dissolve the wax-like substance or the capsule of the coloring agent, and can be quickly removed. The diaphragm 7 that diffuses and permeates may be one that allows the wax-like substance 1 that melts at a predetermined temperature to permeate and diffuse together with the coloring agent 2, for example, if an appropriate material such as paper, plastic film, or non-woven material is used. good. that time,
In order to appropriately control the passage time, the hole size, density, thickness, etc. may be appropriately controlled. Alternatively, the permeation rate may be controlled by treatment with a suitable treatment agent such as silicone. By doing so, the grace period can be adjusted effectively. Next, the encapsulation techniques used in the present invention include the known method of coacervation method;
An in situ 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 film-forming ingredients used in capsules are gelatin,
These include alginic acid, acrylic polymers, methacrylic polymers, melamine, and epoxy polymers. The capsule should have a size of about 1 to 300 μm so that it 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, causing problems in the coating process. The method for destroying the capsule of the label of the present invention is not particularly limited, but a hand roller or the like may be used to understand the time- and temperature-dependent changes when the entire system is exposed to a temperature higher than a predetermined temperature. It is desirable to break under a constant load. The temperature-indicating label of the present invention can be obtained by covering the entire basic structure shown in FIG. 1 with a transparent plastic film, and further applying an adhesive layer if desired. Furthermore, additives for improving the necessary conditions can be added to the composition constituting the temperature label of the present invention within a range that does not prevent irreversible discoloration. Typical examples of such additives include antioxidants, ultraviolet absorbers, inorganic fillers, pigments, plasticizers, lubricants, and antistatic agents. Methods for attaching the temperature-indicating label of the present invention to low-temperature storage products include pasting with an adhesive, hanging it up as a label, and directly adhering it to a low-temperature-preservation container. Preferred examples for which the temperature-indicating label of the present invention can be used include, but are not limited to, kamaboko, raw noodles, yogurt, overnight pickles, and sushi. Example 1 A mixed solution (4:1) of methyl myristate microcapsules in which crystal violet lactone (CVL) was dissolved and ethylene-vinyl acetate copolymer emulsion was coated on the surface of 65 g of high-quality paper in a coating amount of 60 g.
It was applied at g/m ² . Movinyl 184E (ethylene vinyl acetate emulsion) was applied as a barrier layer on top of this at 3 g/m ² . Adhesive 20 on it
g/m ² , and a separator (diaphragm) was attached to prepare tack paper. Color change agent ink A prepared with the following formulation was applied to this surface.
is printed by screen printing (90 meshes), and 10
A coating weight of g/m ² was obtained. A label was prepared by providing a protective layer on the upper layer with a polyester laminate film. When this label was marked with a stamping machine and left at room temperature, coloring started in 2 to 3 minutes and turned deep blue in about 2 hours. Next, after marking this label with a stamping machine,
It was attached to the inside of a beaker, the top of the sheet was filled with water, and then left. Similarly, the color developed after 2 to 3 minutes and turned deep blue in 5 hours. No delay in color development or decolorization was observed. Color developer ink A formulation 1 Zinc t-butylsalicylate 10 parts by weight 2 Alkyd resin (50%) 40 parts by weight 3 Hydrocarbon solvent 20-100 parts by weight 4 Organic bentonite 3-12 parts by weight Mix 1, 2, and 4 and uniformly dispersed with a homogenizer. Dilute with 3 and use so that the viscosity is 1000 to 2000 cps. Comparative Example 1 The tack paper of Example 1 was screen printed with a mixture of zinc t-butylsalicylate and alkyd resin at a coating weight of 10 g/m ² . A label made of polyester laminate film was marked with a stamping machine. When I attached it to the inside of a beaker and filled it with water, the color started to develop after 2 to 3 minutes, but 2
The coloring stopped progressing around the time, and in some cases the coloring partially disappeared as water penetrated. Example 2 Using the tack paper of Example 1, a color change ink with the following formulation was screen printed on the surface.
g/m ² was applied. Formulation 1 Zinc t-butylsalicylate 10 parts by weight 2 Alkyd resin 20 parts by weight 3 Silicone varnish 20 parts by weight 4 Diluent solvent 5 to 20 parts by weight This surface layer was laminated with a polyester film to form a label. After marking this label with a stamping machine, it was attached to the inside of a beaker, and the beaker was filled with water. When color development was measured at room temperature (20℃), it was 2-3.
The color started to turn dark blue in 5 hours. Effects of the Invention The temperature label of the present invention does not develop color during storage at room temperature unless stamped. The temperature-indicating label of the present invention does not need to be stamped in a low-temperature environment, and even if stamped in a high-temperature environment, it does not immediately develop color, and there is a grace period until it cools down to a low temperature, so it is easy to use. It's convenient.

[Brief explanation of the drawing]

FIGS. 1 to 5 are schematic diagrams showing the basic structure of the temperature-indicating label of the present invention. The symbols in the figure are as follows. 1... Wax-like substance, 2... Color former, 3... Color change agent, 4...
capsule film, 5... layer, 6... binder, 7
...Diaphragm, 8...Waterproofing agent.

Claims (1)

[Claims] 1 (i) Wax-like substance 1 that melts at a predetermined temperature; (ii) Color former 2; (iii) Color change agent 3 that changes color upon contact with color former 2;