JPS6199829A - Temperature history displaying element - Google Patents

Abstract

PURPOSE:To enable the easy detection of the maximum temp. in the past temp. history by affecting a color coupler and coloring assistant via the temp. sensitive permeation film having the permeability of a substance at more than the specified temp. CONSTITUTION:The temp. sensitive permeation film 4 of the inside of a cell 10 becomes permeable of a substance when the cell 10 becomes at more than the specified temp. and the enzyme affecting substance (coloring assistant) of the inside of the solution inside a chamber 3 enters the chamber 2 containing a color coupler and enzyme with permeating the film 4. The atmosphere inside the chamber 2 is changed to be oxidative, reductive or acidic, alkaline according to the combination of the invaded enzyme affecting substance and enzyme, and the color coupler colors, discolors or decolor and the hue thereof is not changed even when the temp. of the cell 10 falls. The past history of the temp. of the cell 10 can be thus known and on the other hand it is understood that the temp. causing the permeability of the film 4 has not been experienced.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a temperature history display and element that displays the highest value of temperature history, and particularly relates to a temperature history display and element that displays the highest value of temperature change in the temperature range of -30°C to 60°C. The purpose of the present invention is to provide a temperature history display element suitable for displaying.

(Prior art) Conventionally, temperature display elements have been widely used, such as those that utilize the expansion of liquid due to temperature changes, those that utilize changes in the orientation of molecules of liquid crystalline substances due to temperature changes, and those that use thermostat pigments. has been done.

(Point B while the invention remains to be solved) All of the conventional temperature display elements described above sequentially display the temperature at each time, but cannot store and display past temperatures. Therefore, it is not possible to know what kind of temperature changes materials, such as food and drinks, that are easily altered by temperature changes undergo from production to distribution to consumers. Many industrial materials are also susceptible to deterioration due to temperature rise, and there is a drawback that deterioration due to past temperature increases cannot be detected later. Furthermore, in factories and other chemical reactions, it is possible to know the reaction temperature at any given time, but if the reaction temperature is not constantly monitored, it is not possible to know what kind of temperature changes have occurred in the past. Although it is possible to know such temperature history using various temperature monitoring devices, these monitoring devices are complicated and expensive, and cannot be used in practice under conditions where costs are strict, such as in the food distribution process. Therefore, it is widely desired to provide an inexpensive and compact temperature history display element.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to solve the above-mentioned drawbacks of the prior art and to provide a temperature history display element that can be used in a wide range of applications, is inexpensive, and is easy to handle.

(Disclosure of the Invention) In order to solve the above-mentioned drawbacks of the prior art and achieve the above-mentioned object of the present invention, the present inventor has conducted intensive research and found that a color former and a color-forming aid are heated at a temperature above a specific temperature. The present invention was completed based on the finding that the highest temperature in the past temperature history can be easily detected with the naked eye by acting through a temperature-sensitive permeable membrane that is permeable to substances.

That is, the present invention comprises a sealed container capable of detecting a color change of the contents, and a temperature-sensitive permeable membrane that partitions the inside of the container into a plurality of chambers, and at least one of the partitioned chambers contains a coloring agent. A temperature history characterized in that at least one other chamber contains a coloring aid, and the coloring agent and the coloring aid act through the temperature-sensitive permeable membrane at a temperature of -1M. It is a display element.

To explain the present invention in detail, the main feature of the present invention is that the coloring agent and the coloring aid are separated by a temperature-sensitive permeable membrane that exhibits substance permeability at a temperature above a specific temperature. In other words, it does not exhibit substance permeability at temperatures below a certain temperature, but
At temperatures above a certain temperature, it passes through the coloring agent and/or coloring aid, allowing interaction between the coloring agent and the coloring aid;
As a result, the display element takes on a hue different from the original hue, and this takes advantage of the fact that even if the temperature subsequently drops below a specific temperature, the color that once appeared does not return to its original color.

The color forming agent constituting the temperature history display element of the present invention refers to changes in the environment of the color forming agent, such as oxidizing atmosphere, reducing atmosphere,
It refers to a dye or a dye precursor that develops, changes color, or discolors depending on hydrogen ion concentration (pH), etc. Preferred specific examples of such color formers include, for example, those that develop, discolor, or discolor due to a reducing atmosphere. , tetrazolium blue (colorless → blue), tetrazolium purple (colorless → reddish-purple), and tetrazolium violet (colorless divine purple).As a coloring agent that develops, changes color, or disappears depending on the oxidizing atmosphere, Michler's ketone (colorless → blue) is mentioned. ), leukotriphenylmethane (colorless → blue),
Benzoylleucomethylene blue (colorless → blue), 4-
Examples include 7minoantibilin (colorless → red), auramine leuco (colorless → yellow), tyrosine (colorless → brown), indoxyl (colorless → blue), etc., and can develop, change color, or disappear depending on changes in hydrogen ion concentration. Examples of coloring agents that produce color include those illustrated in Table 1 below.

15l Color change Color change area 1 and cliff 11
Sumi U Metacresol Purple Red → Yellow 1.2~2.8 Thymol Blue Red → Noble 1.2~2.8 Bromophenol Blue Yellow → Blue 3.0~4.6 Promocresol Green Yellow → Blue 3.8~ 5.4 Chlorophenol Red Yellow → Red 4.8-6.4 Bromophenol Red Yellow → Red 5.2-8.8 Bromocresol Burple Yellow → Purple 5.2-6.8 Bromothymol Blue Yellow → Blue 8. 0~7.8 Phenol Red Yellow → Red 6.8~8.
4 Cresol Red Yellow → Red 7.2~8.8 Metacresol Purple Yellow → Purple 7.4~9.0 Thymol Blue Yellow → Blue 8.0~9.6 Cresol Phthalein Colorless → Red 8.2~8. 8. The following two examples are examples of preferred color formers, and any other color formers similar to those in item L that develop, change color, or discolor due to changes in the environment are similarly useful in the present invention.

One preferred embodiment of the invention utilizes an enzyme in conjunction with a color former. Preferable enzymes to be used are those that can change the pH of the environment of the coloring agent through oxidation, reductase, or enzymatic reactions.Specific examples of such enzymes include lactate dehydrogenase, glucose, and
Oxidation reductases such as oxidase, succinic dividerogenase, cholesterol oxidase, catalase, squalene fist hydroxylase, peroxidase, tyrosinase, α-chymotrypsin, pepsin,
Examples include hydrolytic enzymes such as trypsin and thermolysin. The above examples are preferred enzymes in the present invention, and other enzymes having similar functions can also be used in the present invention. When using such an enzyme, it is preferable to adjust the pH of the coloring agent solution to an appropriate value for the enzyme to work. Buffers such as acids, potassium hydrogen phthalate or mixtures thereof can be added.

In the present invention, the temperature-sensitive permeable membrane for separating the above-mentioned color former and the below-mentioned color-forming aid is capable of transmitting the above-mentioned color former and/or color-forming aid only at a temperature above a specific temperature. Any membrane can be used as long as it affects the properties to be obtained.Explaining with reference to the preferred embodiment of the present invention, which utilizes an enzyme, such a temperature-sensitive permeable membrane can: Substances whose phase changes easily depending on temperatures between -30°C and 60°C, where acids are also likely to be encountered 1 Examples of biologically relevant substances: phospholipids, cholesterol esters, glyceride glycolipids, fatty acid salts Examples include so-called liquid crystal substances such as . Specific examples of preferred phospholipids include those illustrated in Table 2 below.

Tc(”0) 1-I l Engineering 1j is 1 [degree y egg・
Phosphatidylcholine EPC-15 to -7 Dilauriloylphosphatidylcholine (C12:O) DLPC-1,8 Simyristoylphosphatidylcholine (CI4:0) DMPC23 Dipalmitoylphosphatidylcholine (018:0), DPPC41 Distearoylphosphatidylcholine (C113:O ) DS PC851-
Myristoyl-2-balmitoylphosphatidylcholine (c 14:0118:O) MPPC271-
Valmitoyl-2-myristoylphosphatidylcholine (CI4:0.18:0) PMPC351-Valmitoyl-2-stearoylphosphatidylcholine (c18:0.14:O) PSPC441-
Stearoyl-2-balmitoylphosphatidylcholine (018:o, 18:O) 5PPC47 Dioleoylphosphatidylcholine (CI8:1) DOPC-22 Silauriloylphosphatidylglycerol DLPG 4 Simyristoylphosphatidylglycerol DMPC23 Dipalmitoylphosphatidylglycerol DPPG 41 Distearoyl phosphatidylglycerol DSPG 55 Dioleoylphosphatidylglycerol DOPG -18 Similistoyl phosphatidyl glycerol
DMPA 45-67 Dimyristoylphosphatidylethanolamine DM P E 50
Dipalmitoylphosphatidylethanolamine DPPE EIO Similistoyl phosphatidylserine DMPS 38 Dipalmitoylphosphatidylserine D P P S 51
Brine phosphatidylserine PS 13-8 Brine phosphatidylserine B S P 3
2 dipalmitoylsphingomyelin D P S P 4
1 Distearoylsphingomyelin D S S P 5
Since it is difficult to form a film with a certain degree of strength by itself using a liquid crystalline substance such as 7 or higher, in the present invention, polyamide (nylon), polyurethane, acetylcellulose,
It is preferable to use synthetic resins or natural polymeric compounds such as polyglutamate, collagen, peptidoglycan, etc. as membrane carriers. The temperature-sensitive permeable membrane in the present invention is
-1- Dissolving or dispersing the liquid crystalline substance as described above and the carrier material as described above in a suitable solvent, preferably at a ratio of about 1 to 70 parts by weight of the phase material per 100 parts by weight of the liquid crystalline substance, It can be obtained by dry or wet film formation using the liquid. The film forming method itself may be a conventionally known method. Naturally, a method such as melt-kneading the liquid crystalline substance and the carrier material without using a solvent may also be used. The temperature-sensitive permeable membrane obtained in this way varies depending on the material used and the material to be permeated, but it is generally preferable to have a thickness of about lθ to 500 pm. The temperature-sensitive transmission film obtained in this way changes the material permeability of the film depending on the phase transition temperature of the liquid crystalline substance used, and combines the selected liquid crystalline substance with the selected coloring agent and/or coloring aid. It exhibits clear selective substance permeability between agents.

In the present invention, the coloring aid that is separated from the coloring agent through the temperature-sensitive transmission membrane as described above is a coloration aid that permeates through the temperature-sensitive transmission membrane at a temperature higher than a specific temperature and causes the coloring agent to develop, change color, or decolorize. If the color former develops, changes color, or discolors due to oxidation, the oxidizing substance is used; if the color former develops color, changes color, or discolors due to reduction, the reducing substance is used; and the color former develops color due to pH changes. If the color changes or disappears, use acidic or alkaline substances. A large number of such various color development aids are conventionally known, and from these known substances,
They can be easily selected and used by those skilled in the art in connection with the temperature-sensitive permeable membrane described above.

In a preferred embodiment of the present invention, when an enzyme is used together with a coloring agent, a compound with which the enzyme can act with the coloring agent is used as the coloring aid. For example, corresponding to the above-mentioned enzymes, L-rafti I., NA
D, β-D-glucose, succinic acid, NADP, H2O
,, squalene phenol, quinone, organic acid anhydride, T
Examples include substances such as CNQ and TTF, donors, and acceptors. These compounds are just preferred examples, and any other compounds that can act with enzymes to create an oxidizing atmosphere, reducing atmosphere, or change in pH can be used in the present invention. In addition, as a color development aid in an embodiment that does not use an enzyme, a certain amount of -fti
Conventionally known organic oxidizing agents, organic reducing agents, organic acids, organic amines, and the like having a molecular weight that allows temperature-selective permeation through the above-mentioned temperature-sensitive permeable membrane.

1-1 The main characteristic components of the present invention have been explained below.
In the present invention, a coloring agent and a coloring aid as described in "2" are separated by a temperature-sensitive permeable membrane. Such compartmentalization takes place in a container having means by which a change in color of the contents can be detected from the outside by some step. Such containers are
Any material may be used as long as it is preferably at least partially transparent and does not pass through the solvent of the coloring agent and coloring aid, preferably an aqueous medium, such as glass, polyethylene terephthalate, acrylic resin, etc. It is. A cell suitable for the purpose of use may be created using such a transparent base material.

Next, a method for manufacturing the temperature history display element of the present invention will be explained with reference to the accompanying drawing ζ1, which schematically shows a preferred embodiment of the present invention.For example, as shown in FIG. ) and (1′), the temperature-sensitive permeable membrane (4
) and seal both ends with adhesive (5) to form a cell (1).
0). Such cells may have any size and thickness; for example, when used in the distribution process of fresh foods, the substrates (1) and (VI) may have a thickness of, for example, 0.1 to 2 Wm. The thickness of the cell (10) can be set to about 0.3 to B+m, and it can be made into a chip shape of about several mrn' to several Cgo.

One chamber (2) partitioned by the temperature-sensitive permeable membrane (4) is charged with a solution containing a coloring agent, preferably an aqueous solution. In such a solution, a water-soluble polymer that is inert to the coloring agent, such as polyacrylamide, agar, gelatin, etc., may be dissolved or dispersed. It is also possible to absorb and support the same.

All of these polymers and absorbent materials are colorless, white, etc.
It is preferable to use a coloring agent that does not interfere with the identification of color changes. The coloring agent used may have any concentration as long as it does not develop color, discolor, or discolor due to changes in the environment, preferably at a concentration that is visible to the naked eye, but generally it is about 0.01 to 1.0 part. is sufficient. In addition, when an enzyme is used together with the coloring agent, when the coloring aid passes through the temperature-sensitive permeable membrane (4) into the chamber (2), the enzyme acts on the coloring aid and releases the coloring agent. Coloring,
It is sufficient to have enough amount to change or erase the color, but -#μ
' is approximately 1 to 500+sg/u.

Next, the other chamber (3) is charged with a solution, preferably an aqueous solution, of a coloring aid. The above-mentioned aqueous polymer may be added to the charged solution together with a color development aid, or an absorbent material may be added together with the charged solution. Similar to the coloring aid described above, the coloring aid may have any concentration as long as it can develop, change color, or decolorize the coloring agent.

After charging the necessary components into the cell (lO) as described above, the temperature history display element of the present invention can be obtained by completely sealing the cell (!0).

The temperature history display element of the present invention as described above can be used in accordance with the temperature characteristics of the temperature-sensitive transmission film used, that is, in accordance with the temperature characteristics of the liquid crystal material used, for example, at -306C to 60C. Maximum temperature can be recorded and displayed. To explain in more detail an example using an enzyme, which is a preferred embodiment of the present invention, when the temperature of the cell reaches a certain temperature or higher, the temperature-sensitive permeable membrane in the cell becomes permeable to substances, and the inside of the chamber (3) becomes permeable. The enzyme-active substance (color-forming aid) in the solution passes through the temperature-sensitive permeable membrane (4) and enters the chamber (2) containing the color-forming agent and enzyme, where it acts on the enzyme-active substance and transforms the chamber. (2) The atmosphere inside changes to be oxidizing, reducing, acidic or alkaline due to the combination of the enzymatically active substance and the enzyme, and the color forming agent develops, changes color or disappears. After that, even if the temperature of the cell falls, the color develops,
The hue of discoloration or discoloration does not change, so it is possible to know the past temperature of the cell, that is, the temperature at which the temperature-sensitive permeable membrane became permeable to substances. The absence of a color change indicates that the cell has not previously experienced a temperature at which its temperature-sensitive membrane becomes transparent.

Alternatively, create multiple temperature-sensitive permeable membranes that become permeable to substances at a specific temperature and incorporate them into one cell, or create multiple cells each having their own temperature-sensitive permeable membranes. By doing so, the past temperature history can be known more clearly.

Next, the present invention will be specifically explained with reference to Examples.

Example 1 300 mg of triacetyl cellulose and 100 mg of DPPC (dipalmitoyl phosphatidylcholine) are added to acetone 51 purified by distillation, and the mixture is stirred for 2 hours in a 1-cap Erlenmeyer flask. The solution is then sonicated for 20 minutes to disperse the IIPPc into the solution. The solution was spread on a glass plate with an area of 15 x 15 crrf, and the solvent was evaporated in a vacuum dryer at room temperature under reduced pressure to form a film. Intestines) were created. The membrane is selectively permeable to glucose at temperatures above about 41'0. The above temperature-sensitive permeable membrane was attached to the center of the container, and the buffer solution was placed in the right chamber and the glucose 0.0% was placed in the left chamber.
When a 1M aqueous solution was added and the temperature was changed, the glucose concentration in the right chamber was as shown in Figure 2, and the permeability of glucose rapidly increased around 41°C, which is the phase transition point of DPPC. It can be seen that this is an excellent temperature-sensitive permeable membrane.

A temperature history display element of the present invention as shown in FIG. 1 was prepared using the above-mentioned temperature-sensitive transmission film in the following manner. Fix glass wool on the substrate and add 0, 1 mg/ml on it.
1 ml of glucose oxidase aqueous solution, 0, 1 r
sg/ml peroxidase aqueous solution l1, l Om
4-aminoantipyrine of M2. Oa+1.10mM
The glass wool was impregnated by dropping 2.01 and 10 M of dimethyl geltaric acid 11 into the Pheno-J. The temperature-sensitive permeable membrane described above is placed on top of that, and then glass wool impregnated with 100g/ml of glucose aqueous solution 21 is layered on top of the temperature-sensitive permeable membrane, and then a plate made of the same material as the substrate is layered. The temperature history display element of the present invention was prepared by sealing both sides with an α-cyanoacrylate adhesive.

When the temperature history display element described in L was placed in a constant temperature room and the temperature was gradually raised from room temperature, the color of the temperature history display element changed from white to reddish-purple at 43 °C, which is near the phase transition temperature of DPPC (41 °C). . Further, even when this temperature history display element was returned to room temperature, the reddish-purple color remained unchanged. Therefore, if this temperature history display element is white, this temperature history display element
If the temperature has not exceeded 43°C, and the temperature has turned reddish-purple, this indicates that the temperature history display element has exceeded 43°C at least once in the past.

Example 2 Under the same conditions as Example 1, DP was used as the liquid crystal material.
A temperature history display element of the present invention was prepared in the same manner as in Example 1 using DLPG (silauriloyl phosphatidylglycerol) instead of PC and benzoylleucomethylene blue instead of 4-aminoantipyrine as a coloring agent.

This element turns blue when the temperature of the element exceeds 5℃,
If the temperature was below 5°C, it remained white.

By pasting this temperature history display element on fresh foods, etc., it is possible to determine whether the temperature of the food has exceeded 5° C. in the past, and it can be used as a measure of its freshness.

Example 3 300 g of polyurethane was added to purified DMAC (dimethylacetamide)! : Add 100 g of DMPC (dimyrystyle fostidylcholine) and stir for 2 hours in an Erlenmeyer flask with a lid. The solution is then sonicated for 20 minutes to disperse the DMPC in the solution. The solution was poured onto a glass plate and spread to about 15 x 15 crn'.
A temperature-sensitive permeable membrane (thickness: 300 #Lm) was prepared by evaporating the solvent in a vacuum dryer at room temperature and under reduced pressure. The temperature-sensitive permeable membrane obtained here has a temperature sensitivity of 11? It shows transparent transparency.

Next, fix the glass wool on the substrate, and
l IIg/ml aqueous solution of cholesterol oxitanase 11, O, l mg/ml aqueous peroxidase solution 11.10 1M dimethyl geltaric acid 11.10
A mixture of 2.01 s M of an aqueous solution of 4-aminoantipyrine and a 10 mM aqueous phenol solution is added dropwise for impregnation. The second part is covered with the above-mentioned temperature-sensitive permeable membrane, and glass wool impregnated with 2 ml of a chloroform solution of 100 μg/kg of cholesterol is placed on top of the temperature-sensitive permeable membrane. Furthermore, plates made of the same material as the substrate were stacked on top of each other, and both sides were sealed with an adhesive to create a temperature history display element of the present invention.

The temperature history display element thus produced was placed in a constant temperature bath, and when the temperature was gradually raised from room temperature, the color of the element changed from white to reddish-purple at 24°C, which is around the phase transition temperature of DMPC of 23°C.

Therefore, depending on this temperature history display element, it can be determined whether the temperature history display element has exceeded 24°C in the past.

[Brief explanation of the drawing]

FIG. 1 schematically shows an example of the temperature history display element of the present invention, and FIG. 2 shows the glucose permeability of the temperature-sensitive permeable membrane of the example (the vertical axis is the glucose permeability expressed in absorbance). concentration)
.

Claims (4)

[Claims] (1) Consisting of a sealed container that can detect color changes in the contents and a temperature-sensitive permeable membrane that divides the inside of the container into a plurality of chambers,
At least one partitioned chamber contains a color former, and at least one other compartment contains a color former, and as the temperature rises, the color former and the color former act through the temperature-sensitive permeable membrane. A temperature history display element characterized in that: (2) The temperature history display element according to claim (1), wherein the temperature-sensitive transmission film contains a liquid crystalline substance. (3) The temperature history display element according to claim (1), wherein the color development aid contains an enzyme-active substance. (4) Claim No. (1) in which the coloring agent contains an enzyme
Temperature history display element described in section.