JPH09113500A - Time indicating material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a material for indicating the time variation at a specified temperature or the date of starting measurement of temperature-time accumulation value and time. SOLUTION: The inventive material comprises a part 1 composed of an agent A carried by a carrier and an agent B not touching the agent B and indicating the time or temperature-time accumulation value as a color change by bringing the agents A and B into contact, and a part 2 integrated with the part 1 for indicating the date when the agents A and B are brought into contact. The agent A, B is composed of a combination of a radical generating agent and a coloring matter which changes the color through reaction and/or a precursor thereof.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to displaying a time or temperature-time integrated value as a color change by bringing a dye and / or a dye precursor which change color by reacting with a radical generator and a radical into a color change. , A display material for displaying the date and time when the measurement is started.

[0002]

2. Description of the Related Art At present, when articles are stored at a certain temperature for a certain period of time, a demand for a display material for monitoring the temperature and time is increasing year by year. That is,
For frozen foods, refrigerated foods, fresh foods, and chemicals such as paints and adhesives, the storage temperature is usually specified and the effective period is also limited.
However, a display material that simultaneously inexpensively measures temperature and time, and a material that indicates whether or not a product whose manufacturing date is indicated is certainly stored at a specified temperature have not been found in the market so far.

[0003] Conventionally, as a material for displaying temperature / time history by color change, a pattern using a eutectic acetylene-based mixture which displays a range of several tens of hours at a temperature of about 100 ° C by changing from pink to metallic green. US Pat. No. 4,189,399 (issued 1980.2.19), US Pat. No. 4,208,186 (issued 1980.6.17), US Pat. No. 4,276,190 (issued 1980.6.30), room temperature U.S. Pat. No. 4,212,153 (issued 1980.7.15) to Kidnius et al., Which uses the reaction of a dye that develops from colorless to purple in a few dozen days to the diffusion of acid or alkali, redox dye and oxygen diffusion U.S. Pat. No. 3,768,976, which uses properties, and U.S. Pat. No. 3,966, Cartab et al., Which uses a composition of a free radical-sensitive dye and a peroxide, which is indicated by the fading of green. No. 414, JP-A-62-190447, which utilizes the coloring of a triarylmethane dye decolorized with a reducing agent by diffusion of oxygen, and Matsuda, which uses a pH indicator and a microorganism that produces an acid. There is JP-A-5-61917. In addition, patents utilizing melting points, diffusion rates, enzyme activities, and the like have been disclosed.

[0004] Although various display materials have been proposed but not actually put on the market, they are inconvenient to handle in a solution state, and the method of starting time measurement is complicated or unclear. Or the price is high. For example, the invention of Cartab et al. (US Pat. No. 3,966,414) using a composition of free radical sensitive dye and peroxide is similar to the composition of the present invention. To carry a dye and a peroxide on a glass fiber paper to form a display material, they dissolve the dye and the peroxide in a solvent and develop the solution on the glass fiber paper.
Here, from the viewpoint of time measurement, the reaction has started at the time when the dye and the peroxide are dissolved, and there is a disadvantage that the measurement is not practically suitable for time measurement at a temperature lower than room temperature.

Further, as a method of displaying the date and time when the measurement of the time or temperature-time integrated value is started, there are methods such as those found in existing food packaging such as ink jet printing, date stamps and date labels. However, these can only display the manufacturing date, etc., and cannot display how long the temperature has been exposed.

As described above, an inexpensive material which simultaneously displays the temperature-time integrated value and the manufacturing date has not been found yet.

[0007]

DISCLOSURE OF THE INVENTION The present invention displays that a predetermined time has elapsed at a predetermined temperature or a temperature-time integrated value by a clear change in hue, and displays the date and time when the measurement is started easily and inexpensively. The present invention provides a time display material that enables the following. That is, the present invention displays a temperature-time integrated value as a change in hue by a display unit (1) composed of a dye and / or a dye precursor that changes color by reacting with a radical generator and a radical,
At the same time, the date and time when the measurement of the time or the temperature-time integrated value is started can be displayed on the display unit (2).

[0008] In general, frozen foods, chilled foods, fresh foods, as well as chemicals such as paints and adhesives, which have a shelf life, are usually limited in shelf life and shelf life. When the temperature is low, the effective storage period is long, and when the temperature is high, the storage period is often extremely short. However, it is the current situation that thermometers are generally installed in storage areas and controlled by displaying the date of manufacture and the expiration date of the warranty. Alternatively, it is unclear whether or not it has been stored at or below a predetermined temperature. In this way, the temperature-time integrated value, which is the total amount of heat of how much time has passed for each article under the predetermined temperature, or at what temperature and how much time has passed, and the predetermined temperature There has been a demand for a method capable of providing a material capable of clearly indicating what has been achieved and at low cost.

[0009]

Means for Solving the Problems The present inventors have found that a radical generator and a dye and / or a dye precursor that change color by reacting with a radical are used to cause a color change depending on the radical concentration. Furthermore, since the radical concentration is defined by temperature and time according to the Arrhenius law, it was found that the temperature-time integrated value, which should be called the time change at a predetermined temperature or the total amount of heat, can be displayed as a color change. Furthermore, by combining this material with a temperature indicator for temperature control, we have found a display material that can confirm that a predetermined temperature has been reached at the same time as the temperature-time integrated value.

The present invention comprises an agent B carried in a carrier and an agent B which is in a non-contact state, and each agent A and agent B are brought into contact with each other to react with each other to obtain a time or temperature-time integrated value as a color. A display material (however, A) that integrally displays a display unit (1) that displays changes and a display unit (2) that displays the date and time when the measurement of time or temperature-time integrated value is started.
The agent and the agent B are a combination of a radical generator and a dye and / or a dye precursor that changes color by reacting with a radical. ).

BEST MODE FOR CARRYING OUT THE INVENTION

In the radical generator used in the present invention, the amount of radical generation at a predetermined temperature is regulated by the difference in the decomposition temperature thereof, and the optimum radical generator is set according to the desired temperature and time to bring the radical into contact with the radical. By doing so, the time for changing the hue of the coloring dye and / or the coloring matter precursor can be determined. That is, since the decomposition rate of the radical generator complies with the Arrhenius law, the amount of radical generation is defined as a function of temperature and time, and as a result, it becomes possible to display the time or temperature-time integrated value.

The amount of heat obtained at a constant temperature or at a fluctuating temperature can be expressed as an integrated value obtained by the product of the temperature at each time and its time. The integrated value of this temperature and time is the temperature-time integrated value. It is defined as For example, refrigerated food such as meat and fish is 20 hours at 30 ° C for 12 hours.
The shelf life or expiration date changes depending on the storage temperature, such as 24 hours at C and 72 hours at 10 ° C. When considering the actual distribution of products, the storage temperature can be considered to be constantly fluctuating though varying in degree.
The problem here is "how many temperatures have been left or stored at what temperature", and this scale is called the temperature-time integrated value. However, temperature 20 ° C
The problem that the deterioration or change in one hour is equivalent to how many hours change at a temperature of 10 ° C. is represented by a simple product of absolute temperature and time because it is defined by the frequency factor and the activation energy in the Arrhenius law. Not something.

As the radical generator, organic peroxides,
Examples thereof include azo compounds and halogenated carbon compounds.
Specific examples of the organic peroxide include dialkyl peroxides such as di-tert-butyl peroxide, tert-butyl cumyl peroxide and dicumyl peroxide, and diacyl such as acetyl peroxide, lauroyl peroxide and benzoyl peroxide. Peroxides, methyl ethyl ketone peroxide,
Ketone peroxides such as cyclohexanone peroxide, 3,3,5-trimethylcyclohexanone peroxide, and methylcyclohexanone peroxide, peroxyketals such as 1,1-bis (tert-butylperoxy) cyclohexane, and tert-butylhydroper Oxide, cumene hydroperoxide, 1,1,3,3-tetramethylbutyl hydroperoxide, p-menthane hydroperoxide, diisopropylbenzene hydroperoxide, 2,5-dimethylhexane-2,5-dihydroperoxide, etc. Peroxy compounds such as hydroperoxides, tert-butylperoxyacetate, tert-butylperoxy-2-ethylhexanoate, and tert-butylperoxybenzoate Although there are such ester compounds, benzoyl peroxide Among these excellent balance between storage stability and radical-generating capacity, it is suitable for radical generator. Examples of the azo compound include azonitriles such as 2,2′-azobisisobutyronitrile and 2,2′-azobis (2-methylbutyronitrile), 2,2′-azobis (2-amidinopropane) dihydrochloride. , Azoamides such as 2,2′-azobis (2-methylpropionamide) dihydrate,
Azoallyls such as 2,2′-azobis (2-methylpropane) can be mentioned. Examples of the carbon halide compound include polyhalogen compounds such as carbon tetrabromide. The radical generator is 1.0 to 20% by weight, preferably 2.0 to 15.0% by weight based on the medium forming the carrier.
% By weight to obtain the time and temperature indicating material of the present invention.

In the present invention, the dye and / or dye precursor, which changes color by reacting with a radical, has a property that hydrogen atoms in the molecule are easily abstracted by the radical, and a change in color is recognized at that time. Taking advantage of this, the time display material of the present invention was obtained. As a mechanism of this color development, a mechanism such as Chemical formula 1 is inferred by taking phenothiazine as an example.

[0015]

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First, the hydrogen atom in the phenothiazine molecule is abstracted and the nitrogen atom becomes a radical. Next, the radical moves to the sulfur atom, and the valence of the sulfur atom changes from divalent to tetravalent. Then, the conjugation extends to the benzene rings on both sides, the light absorptance of the visible light portion changes, and the hue changes. In addition to this, the reaction used in free radical photography and the like as described in "Color Chemical Encyclopedia" (CMC Publishing) is used in the present invention. That is, the color changes due to a reaction of a radical-diphenylamine-based compound or a radical-triphenylmethane-based compound that exhibits a blue color due to a chain reaction that occurs when a hydrogen atom is abstracted by a radical. In addition, Bell & H also found in the "Color Chemical Encyclopedia"
The color is also changed by the reaction of the radical-dye precursor-sensitizer system by the Owell method.

Examples of the dye and / or dye precursor that develops a color upon contact with a radical used in the present invention include phenothiazine-based coloring dyes such as phenothiazine, phenoxazine-based dyes such as phenoxazine, and leuco crystal violet. , Leucomalachite green, crystal violet, leuco crystal violet lactone and other triphenylmethane compounds, and 4- (p-dimethylaminostyryl) quinoline and other quinoline dyes. Preferably, phenothiazine has a characteristic that it is green immediately after contact with a radical and changes to red as the reaction with the radical progresses, which is the most convenient and easy to perceive as a material for indicating the expiration date of an article. It is one of the substances. Further, phenoxazine is one of the most convenient substances which is easy to perceptually recognize as a material for indicating the expiration date of an article, like phenothiazine in that it changes from colorless to ocher. In addition, for applications that indicate effectiveness after a certain period, leucomalachite green, which changes from colorless to blue, is one of the most convenient substances that is easy to perceptually recognize as a material that indicates the expiration date of an article. . The dye and / or dye precursor, which changes color by reacting with radicals, is added in an amount of 1.0 to 20% by weight, preferably 2.0 to 15.0% by weight, based on the medium forming the carrier. The time display material of the invention is obtained. At this time, if the content of the dye and / or the dye precursor is 1.0% by weight or less, the coloration is thin and the visibility is poor even if there are sufficient radicals in the test object.
There is a limit to the radical concentration that can be detected depending on the amount of dye and / or dye precursor added, and when the amount added is small, there will be no change in color tone after color development at a radical concentration above a certain value, and accurate time Cannot be displayed. Therefore, it is necessary to add the dye and / or the dye precursor in an amount suitable for the expected display time. As a rule of thumb, when benzoyl peroxide is used as a radical generator and phenothiazine is used as a dye and / or a dye precursor, phenothiazine is added to 1% by weight of benzoyl peroxide.
Addition of 3 to 1.5% by weight is desirable. Further, even if the amount of phenothiazine added is 20% by weight or more, the degree of color development does not change so much, but on the other hand, the color may develop due to air oxidation during storage of the indicator, which makes it unsuitable for use.

In the present invention, a decomposition catalyst of the radical generator can be added for the purpose of accelerating the decomposition rate of the radical generator, and even if the same radical generator is used, the decomposition rate can be changed depending on the addition amount of the decomposition catalyst. Can be controlled. That is, it is possible to arbitrarily set the time when the hue changes at the predetermined temperature. Specifically, amines and metal compounds are mentioned as decomposition catalysts. That is, as amines, N, N-dimethylbenzylamine, triethylamine, tributylamine, N, N-diethylaniline, N, N-dimethylaniline, N-phenyldiethanolamine, N-phenyldiisopropanolamine, dimethyl-p- Toluidine, diethyl-m-toluidine, triethanolamine, 4-phenylmorpholine, 4,4′-bis (diethylamino) benzophenone, N-phenyl-2-naphthylamine, N, N-dibenzylaniline, N, N-dibenzyl- Metal compounds such as 2-aminoethanol, lithium, calcium, strontium, barium, cerium, zirconium, vanadium, molybdenum, manganese, iron, cobalt, nickel, lauryl salts of metals such as copper, zinc, tin and lead, naphthenic acid. One or more kinds of salts, fatty acid salts such as octylates, oleates and octenoates, resin salts such as rosin salts and chelate compounds such as acetylacetonate complex salts can be used. In particular, it is desirable to use either or both of amines and metal compounds. The amines and / or metal compounds are added in an amount of 0.1 to 200 parts by weight, preferably 1 to 100 parts by weight, based on 100 parts by weight of the radical generator. This greatly expands the range of temperature and time displayed by the time and temperature display material of the present invention.

In the present invention, a radical generator and a dye which changes color by reacting with a radical and / or
Or, as the medium constituting the carrier containing the dye precursor,
Radical generator and dye and /
Alternatively, any dye precursor may be used as long as it is capable of diffusing and maintaining its shape, and is transparent enough to recognize a color change, without any limitation. Specifically, acrylic resin, polyester resin, polyether resin, polyurethane resin,
Any resin such as a silicone resin, an epoxy resin, a vinyl resin, etc., which is used as a binder for ordinary inks and paints, and an adhesive rubber resin used as a general pressure-sensitive adhesive may be used, or a mixed system of several kinds of the above resins may be used. However, it may or may not be diluted with a commonly used solvent such as a ketone solvent, an ether solvent, an alcohol solvent, a cellosolve solvent, a petroleum solvent, or an aqueous solvent. Particularly, the adhesive rubber-based resin is advantageous in that it exhibits an adhesive function when the carrier and the transparent substrate are brought into contact with each other. Specifically, the adhesive rubber-based resin is Tg
Is a resin at room temperature or lower, preferably -10 ° C or lower, and it is desirable that the resin is in a rubber-like region in the temperature range during use.
Examples include tacky acrylic resins, natural and synthetic cis-1,4-polyisoprene rubber, butyl rubber, halogenated butyl rubber, partially vulcanized butyl rubber, styrene-butadiene-styrene block copolymer (SBS), styrene-isoprene-styrene block. Copolymer (SI
S), styrene-ethylene-butylene-styrene block copolymer (SEBS), silicone rubber, chloroprene rubber, nitrile rubber, butadiene rubber, and the like, which are used as the resin for adhesives. In particular, the tacky acrylic resin has a composition and a molecular weight that can be appropriately set to freely change Tg, and can control the diffusion rate of the radical generator and the dye and / or the dye precursor. It is suitable as a medium for the radical generator and the dye and / or dye precursor of the invention.
The adhesive acrylic resin has a functional group such as a hydroxyl group, a tertiary amino group, a carboxyl group, an amide group, or a nitrile group, and is generally used as an acrylic resin for an adhesive. Acrylic resins having these functional groups include one or more of monomers having a hydroxyl group, a tertiary amino group, a carboxyl group, an amide group, a nitrile group, and the like, and an alkyl (meth) acrylate, vinyl acetate, vinyl propionate. And copolymers with monomers such as vinyl ether and styrene. The reaction is an ordinary radical polymerization, and there is no limitation on the reaction method, and it can be carried out by a known polymerization method such as solution polymerization, bulk polymerization and emulsion polymerization. Solution polymerization is preferable because it can be operated.
The solvent may be any solvent, such as methyl ethyl ketone, methyl isobutyl ketone, toluene, cellosolve, ethyl acetate, and butyl acetate, as long as it dissolves the resin of the present invention. A single solvent or a mixture of a plurality of solvents may be used. Further, the polymerization initiator used in the polymerization reaction is also known such as benzoyl peroxide, acetyl peroxide, methyl ethyl ketone peroxide, organic peroxides such as lauroyl peroxide, and azo initiators such as azobisisobutyronitrile. Anything can be used, and there is no particular limitation. The purpose is to partially crosslink the adhesive rubber-based resin with a crosslinking agent such as isocyanate and epoxy compound to improve the adhesive property and enhance the cohesive force when the carrier is brought into contact with the radical generator and the dye and / or the dye. The diffusion rate of the precursor can be controlled. Further, the polyurethane resin has good printability such as gravure printing, and is one of the preferable materials as a medium constituting the carrier from the viewpoint of productivity of the display material. Examples of such polyurethane resins include "Ramister R Medium" and "New L", which are trade names of urethane resins for gravure ink manufactured by Toyo Ink Mfg. Co., Ltd.
P supermarket, LP Queen and the like.

In the present invention, the support may be coated on a transparent substrate. The transparent substrate used in this case is an olefin film such as polyethylene or polypropylene, a polyester film represented by polyethylene terephthalate, cellophane, polyvinylidene chloride, polyvinylidene chloride copolymer, polyvinylidene fluoride, polyvinyl chloride, Examples thereof include plastic films such as nylon, polyacrylic acid and polymethacrylic acid. In addition, any material may be used as long as the material has transparency enough to confirm a change in hue.

In the present invention, the carrier may be a printing layer, but the printing layer at that time is a layer using a resin as a medium printed by silk screen printing, gravure printing, offset printing, etc. As for the binder resin, any resin layer can be used as long as it is a resin layer that can be formed by printing.

Examples of the method for bringing the agent A and the agent B carried in the carrier in the display section (1) of the present invention into the non-contact state are as follows. A type in which the agent A and the agent B are supported on separate support bodies, and the support bodies are stacked when the measurement is started. Agent A and agent B are loaded on separate carriers and then laminated, and at least one of the carriers can suppress the mass transfer of agent A or agent B at the storage temperature. The type to start. The agent A and the agent B are respectively supported in separate carriers, and a diaphragm layer capable of diffusing the agent A or the agent B at a predetermined temperature or more is interposed,
A type in which a carrier layer containing agent A / a diaphragm layer / a carrier layer containing agent B are laminated in this order. Either agent A or agent B is microencapsulated and each is placed in a non-contact state on a carrier, and pressure is applied when starting the measurement to break the microcapsule and start the measurement. type. Although various methods can be mentioned above, if the agent B carried in the carrier and in a non-contact state with the agent A can be brought into contact with the agent A and the agent B to react with each other by some operation, For example, it can be used in the display unit (1) of the present invention and does not impose any limitation.

In the present invention, as a display material used for the display unit (2) for displaying the date and time when the agent A and the agent B are brought into contact with each other, that is, the date and time when the measurement of time or temperature-time integrated value is started, ink jet printing is used. Or a date stamp,
Some are found in existing food packaging, such as time recorders and date labels. In addition to this, any material or method capable of displaying the date and time when the measurement is started at low cost is not limited. Also, this display unit (2)
Is adhered or printed on the surface of the display unit (1) for displaying the temperature-time integrated value, or is arranged next to it on the same base material to form the time and temperature display material of the present invention.

[0024]

The present invention will be described below with reference to examples. In the examples, “parts” means “parts by weight” and “%” means “% by weight”.

Resin 1 Butyl acrylate 94.1 parts Acrylic acid 5.9 parts Azobisisobutyronitrile 0.2 parts Ethyl acetate 150.0 parts 125 parts of a mixture of each of the above compositions heated to 80 ° C in a nitrogen atmosphere. To the above, 125 parts of the above mixture having the same composition was added dropwise, and after the addition was completed, the mixture was heated under reflux for 12 hours and cooled to obtain a solution of Resin 1 (solid content 40%).

Example 1 100 parts of a resin 1 solution, 12 parts of a 10% ethyl acetate solution of phenothiazine and 4 parts of a 10% ethyl acetate solution of N-phenyldiethanolamine were stirred and mixed to form a corona-treated PET film. It was coated on the surface and dried by heating at 90 ° C. for 2 minutes to obtain a layer containing the agent A with a film thickness of 20 μm. Next, 100 parts of a solution of Resin 1 and 6 parts of a 40% ethyl acetate solution of benzoyl peroxide were mixed by stirring and applied onto a corona-treated PET film.
It was dried by heating at 0 ° C. for 2 minutes to obtain a layer containing the agent B with a thickness of 20 μm. The layer containing the agent A and the layer containing the agent B were brought into contact with each other to obtain a display unit (1). As the display unit (2), the date and time when the layer containing the agent A and the layer containing the agent B are brought into contact with each other are printed on the label sticker / tack title manufactured by KOKUYO Co., Ltd. with the rotation mark manufactured by KOKUYO Co., Ltd. The time display material 1 was obtained by adhering to the surface of (1). Further, the moment of contact was used as the starting point of time measurement, and the color change was observed in a constant temperature bath at 0 ° C. As a result, the color changed to blue after 6 hours, purple after 48 hours, shrimp brown after 168 hours, and red after 336 hours. Similarly, as a result of color change in a constant temperature bath at 10 ° C., the color changed to blue after 2 hours, purple after 24 hours, shrimp brown after 72 hours, and red after 168 hours. Similarly, as a result of color change in a constant temperature bath at 20 ° C., the color changed to blue after 0.5 hour, purple after 2 hours, shrimp brown after 8 hours, and red after 48 hours. Furthermore, when this time display material 1 was stored in a household refrigerator and the hue after 24 hours was observed, it showed bluish purple between blue and purple, and the temperature in the refrigerator averaged 0 ° C to 10 ° C. It was found that the range was.

Example 2 100 parts of a solution of resin 1 and 12 parts of a 10% ethyl acetate solution of phenothiazine were stirred and mixed, and the mixture was applied onto a corona-treated PET film and dried by heating at 90 ° C. for 2 minutes to form a film. A layer containing the agent A was obtained with a thickness of 25 microns. Next, 100 parts of a solution of Resin 1 was added with 4 parts of t-butyl benzoate.
5 parts of 0% ethyl acetate solution was mixed with stirring, and the mixture was applied onto a corona-treated PET film and dried by heating at 90 ° C. for 2 minutes to obtain a layer containing the agent B with a thickness of 25 μm. The layer containing the agent A and the layer containing the agent B were brought into contact with each other to obtain a display unit (1). As the display unit (2), the date and time when the layer containing the agent A and the layer containing the agent B are brought into contact with each other are printed on the label sticker / tack title manufactured by KOKUYO Co., Ltd. with the rotation mark manufactured by KOKUYO Co., Ltd. The time display material 2 was obtained by adhering to the surface of (1). In addition, the color change in a constant temperature bath at 10 ° C. was observed with the moment of contact as the starting point of time measurement. As a result, the color changed to blue after 168 hours and red after 336 hours. Similarly, as a result of color change in a constant temperature bath at 20 ° C., the color changed to blue after 72 hours and red after 168 hours. Similarly, the result of color change in a constant temperature bath at 40 ° C is
It turned blue after 24 hours and red after 48 hours. Furthermore, when this time display material 2 was stored in an outdoor warehouse and the hue after 48 hours was observed, it showed a purple color between blue and red, and the temperature inside the warehouse was in the range of 20 ° C to 40 ° C on average. It turned out that it was.

[0028]

EFFECTS OF THE INVENTION It has become possible to display the fact that a predetermined time has elapsed at a predetermined temperature or the temperature-time integrated value by a clear change in hue, and to easily and inexpensively display the date and time when the measurement was started. .

Claims (1)

[Claims] 1. An agent B which is in a non-contact state with an agent A supported on a carrier, and each of the agent A and the agent B are brought into contact with each other to react with each other, whereby a time or temperature-time integrated value is changed as a color change. A display material in which a display unit (1) for displaying and a display unit (2) for displaying the date and time when the agent A and the agent B are brought into contact with each other (however, the agent A and the agent B are radical generating agents It consists of a combination of dyes and / or dye precursors that change color by reacting with radicals).