JPH11153497A - Display material and food wrapping material for controlling optimum heating temperature-time for cooking - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a display material for controlling an optimum heating temperature-time integrated value, capable of displaying easily and at low cost the elapse of a predetermined time at a predetermined temperature by use of an apparent change in hue, and a food wrapping material using the display material. SOLUTION: A display material, which comprises a layer containing an A-agent carried within a carrier and a layer containing a B-agent kept out of contact with the A-agent, and which controls the optimum heating temperature-time for cooking in the form of color changes by contacting the A-agent with the B-agent and polymerizing an oxidation polymerizing pigment, and a food wrapping material comprising a food wrapping base material laminated with the display material are obtained. The A-agent and the B-agent are made from combinations of the oxidation polymerizing pigment and an oxidizer.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a display material for controlling the cooking time and temperature in cooking as a color change by polymerizing an oxidatively polymerizable dye, and a food packaging material using the same.

[0002]

2. Description of the Related Art At present, there are many menus in which foods, which can be cooked only by heating in hot water, are sealed in containers such as pouches for many menus for reasons such as simplicity and preservability. I have. Normally, each of these foods requires heating at the appropriate hot water temperature for the appropriate time, but materials that measure and display the heating temperature and time easily and inexpensively have not been found in the market so far. .

Conventionally, as a material for displaying a temperature / time history by a color change, Patel using a diacetylene-based compound which displays a range of several tens of hours at a temperature of about 100 ° C. by changing from pink to metallic green, etc. 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), about room temperature U.S. Pat. No. 4,212,153, issued to Kiddonius et al. (Published on 1980.7.15) using a dye which develops a colorless to purple color in the range of several tens of days and diffusion of an acid or alkali, a redox dye and oxygen diffusivity. U.S. Pat.
No. 768,976, U.S. Pat. No. 3,966,414 to Carttub et al., Which uses a composition of a free radical sensitive dye and a peroxide, which is indicated by the fading of green, and a triarylmethane dye decolorized with a reducing agent. Japanese Patent Application Laid-Open No. Sho 62, such as Buchter Charge, which utilizes coloring by diffusion of oxygen.
And JP-A-5-61917 by Matsuda et al. Using an acid-producing microorganism and a pH indicator. 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 a free radical-sensitive dye and a peroxide is intended to support a dye and a peroxide on glass fiber paper as a display material. Then, a dye and a peroxide are dissolved in a solvent, and the solution is spread on glass fiber paper. Here, from the viewpoint of time measurement,
The reaction has started when the dye and peroxide are dissolved,
There is a disadvantage that it is not practically suitable for measuring time at a temperature lower than room temperature. In addition, most of the color changes seen in the conventional technologies are those in which a certain color develops from transparent and its color density increases, and those in which the other hue fades to become transparent and clear. No color changing material was found.

In general, a product in which food is cooked only by heating it in hot water and sealed in a pouch or the like needs to be heated at an appropriate temperature for an appropriate time. If the temperature of the hot water is too low even if the heating time is appropriate, or if the heating time is short even if the temperature of the hot water is appropriate, a sufficient amount of heat will not be transmitted to the food inside the pouch or the like. If the heating time is too long or the heating temperature is too high, the flavor of food inside the pouch or the like may be impaired, or the texture of meat or eggs may be impaired. In addition, it is not easy to keep the state of heating the food constant, and there are constant fluctuation factors. For example, immediately after the food is put into the hot water, the temperature of the hot water drops. This tendency is remarkable in the case of frozen foods. The degree of the decrease in the temperature of the hot water is considered to depend on the amount of food to be put into the hot water and the amount of hot water used at one time. Variations may occur. Although it is a simple cooking method that only heats in hot water, obtaining the best food finish is not surprisingly easy.

[0006] Further, even when the heating temperature is lower than a predetermined temperature, or when the temperature of hot water is reduced during heating, it is conceivable that the food may be properly finished by heating for a long time. What's ℃ to get the finished food
It is considered that information on how much time has passed in the above, in other words, information on the total amount of heat applied to the food is important. However, in general, in order to properly manage these, it is necessary to prepare equipment such as a timer and a thermometer, which may impair the convenience of foods. Even when these devices are used, even if the heating time can be managed simply, it is not easy to calculate the optimum heating time when the temperature fluctuates during heating or when heating is performed at a temperature other than the predetermined temperature. For this reason, there has been a demand for a material that can clearly and inexpensively indicate that an optimal amount of heat for obtaining an optimal finish of food has been added.

[0007]

SUMMARY OF THE INVENTION The present invention relates to a display material for managing an optimum heating temperature-time integrated value which can easily and inexpensively display that a predetermined time has passed at a predetermined temperature by a clear change in hue. The purpose is to provide used food packaging materials.

[0008]

Means for Solving the Problems The present inventors have found that polymerization is initiated by a simple operation of bringing an oxidatively polymerizable dye into contact with an oxidizing agent, and that the resulting dye has a different color depending on the degree of polymerization. Further, since the polymerization rate is defined by the temperature and the time according to the Arrhenius rule as in the case of the ordinary chemical reaction, the temperature-time integrated value, which can be called the total of the time change and the calorific value at a predetermined temperature, can be displayed as a color change. This led to the present invention.

That is, the present invention relates to a layer containing the following agent A supported on a carrier, and a layer B containing the agent A in a non-contact state.
This is a display material comprising a layer containing an agent and controlling the optimal heating temperature and time for cooking as a color change by contacting the agent A and the agent B to polymerize the oxidatively polymerizable dye. However, A
The agent and the agent B comprise a combination of an oxidatively polymerizable dye and an oxidizing agent. The present invention also relates to a layer containing the agent A and / or B
The above-described display material, wherein the layer containing the agent is a resin layer laminated on a transparent substrate on which a color sample for determining a heating temperature-time is printed.

[0010] The present invention is the above-mentioned display material, further comprising a member to be attached to a food packaging material. Further, the present invention is a food packaging material obtained by laminating the display material on a food packaging substrate. Further, the present invention is the food packaging material described above, wherein a color sample for determining the heating temperature-time is printed on the food packaging substrate.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION The oxidatively polymerizable dye used in the present invention is a compound which reacts upon contact with an oxidizing agent to initiate a polymerization reaction of the dye and polymerize to develop a predetermined hue at a predetermined degree of polymerization. Before polymerization, it may be colorless or colored. The reaction rate of this polymerization reaction is determined by the difference in temperature, similarly to a normal chemical reaction. Further, the oxidatively polymerizable dye in the present invention is a dye whose hue changes or its color density changes depending on the degree of polymerization, and its hue is defined by temperature and time. That is, since the polymerization rate follows the Arrhenius rule, the degree of polymerization of the dye is defined as a function of the absolute temperature and time, and as a result, the time or the integrated value of temperature-time can be displayed as a color change. By using the present invention based on this principle, it is possible to obtain information on the elapsed time at a specified temperature when heating a food packaging material. In addition, it is possible to obtain information on the time when the optimal amount of heat was applied when the heating was performed at a temperature other than the specified temperature or when the heating was performed under a fluctuating temperature.

The amount of heat obtained at a constant temperature or a fluctuating temperature can be expressed as an integrated value obtained by multiplying the temperature at each time point by the time, and the integrated value of the temperature and the time is calculated as a temperature-time integrated value. Is defined. For example,
Some foods sealed in pouches or the like require heating at 98 ° C for 5 minutes in hot water for optimal finishing, but 95 ° C for about 7 minutes in boiling water. The time for obtaining the optimum finish varies depending on the heating temperature, for example, about 4 minutes. Further, it is difficult to keep the actual heating state constant, and it is considered that fluctuations such as a decrease in the temperature of hot water immediately after the introduction of food are caused. The problem here is "how many times the temperature has been heated and how long", and the measure is the temperature-time integrated value. However, temperature 9
The problem that a change in 0 ° C for 1 minute corresponds to a change in temperature at 80 ° C for a number of minutes is represented by a simple product of absolute temperature and time because it is defined by the frequency factor and activation energy in the Arrhenius law. is not.

The color development in the present invention is such that the oxidatively polymerizable dye is polymerized by contact with an oxidizing agent, and the hue changes depending on the degree of polymerization of the resulting polymer. It is considered something. The oxidizing agent pulls out a hydrogen atom bonded to the nitrogen atom in the molecule to initiate polymerization, and further, any one of hydrogen at the 1, 2, 3, 4, 6, 7, 8, and 9 positions in the phenothiazine molecule. The atoms are abstracted. It is presumed that this molecule and a neighboring phenothiazine molecule in a similar state are polymerized by using a carbon atom from which the nitrogen atom and hydrogen atom at the 10-position are extracted as a bonding site. FIG. 1 shows a mass spectrum of phenothiazine obtained by polymerizing t-butyl peroxybenzoate of Example 1 using the oxidizing agent at the initial stage of polymerization. Although the details of the reaction mechanism are not clear, it is clear from FIG. 1 that phenothiazine is polymerized by the reaction between the oxidizing agent and phenothiazine.

It is considered that the hue changes because the conjugated system changes as the polymerization of phenothiazine proceeds and the absorption wavelength shifts. The relationship between the hue of phenothiazine, the degree of polymerization and the distribution thereof is determined based on the hue visually and the molecular weight from a mass spectrometer.
Was green, the degree of polymerization 3 was blue, and the degree of polymerization was 4 to 10 and red. It is also presumed that navy or purple color is formed depending on the ratio of the polymers having different polymerization degrees. Regarding the other phenothiazine derivatives and phenoxazine derivatives, the electronic state of the conjugated system varied greatly depending on the type of the substituent bonded to the phenothiazine skeleton, and a different hue change was observed for each substituent. In any case, the developed hue is determined by the degree of polymerization of the phenothiazine derivative and the phenoxazine derivative and their distribution, and the color tone changes as the polymerization proceeds. The structure and the positions of the constituent atoms of the phenothiazine molecule referred to herein follow the following formula.

[0015]

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The oxidatively polymerizable dye used in the present invention is not particularly limited as long as it is oxidatively polymerized and exhibits a predetermined hue at a predetermined degree of polymerization. Specifically, the oxidatively polymerizable dye referred to herein refers to a dye that is oxidized and polymerized by an oxidizing agent represented by a metal salt or the like and exhibits a predetermined hue at a predetermined polymerization degree, and is colorless before polymerization. It is defined as an oxidatively polymerizable dye. Oxidatively polymerizable dyes are more specifically benzene derivatives such as aniline, phenol, thiophenol and their derivatives, 5-membered aromatic heterocyclic compounds such as pyrrole, thiophene, furan, selenophene, tellurophene and their derivatives, carbazole And condensed 6,5,6-membered aromatic heterocyclic compounds such as dibenzothiophene and derivatives thereof, and compounds represented by the following formulas.

[0017]

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Wherein R1 to R7 are hydrogen, halogen, alkyl having 1 to 8 carbon atoms, alkoxy, aryl, substituted aryl, heterocyclic aryl, hydroxyl, amino, cyano, aldehyde, carboxyl, nitro, nitroso. And an atom and an atomic group selected from
Consists of atoms selected from sulfur, oxygen, selenium, and tellurium. The binding site is 1 in R1 to R4.
It is selected from the 2-, 3-, and 4-positions, respectively, but two or more substituents selected from R1 to R4 are not bonded to one position, and are bonded one by one to each position. Similarly, for R5 to R7, the 6-position, 7-position, 8
And three positions are selected from the 9th and 9th positions, respectively, but two or more substituents selected from R5 to R7 are not bonded to one position, and one is bonded to each of the selected three positions. I do. In addition to the above, any substituents can be used for R1 to R7 as long as the substituents do not hinder polymerization.

More specifically, phenothiazine, 3,7
-Dibromophenothiazine, 2-chlorophenothiazine, 4-methylphenothiazine, 3,7-dimethylphenothiazine, 4,6-dimethylphenothiazine, 2-acetylphenothiazine, 3-vinylphenothiazine,
3,7-diamino-phenothiazine, 3,7-bis-
(Dimethylamino) -phenothiazine, 3,7-bis-
(Diethylamino) -phenothiazine, 2-hydroxy-phenothiazine, 3-formyl-phenothiazine, 3
-Carboxyl-phenothiazine, 3,7-dimethoxy-phenothiazine, 1-nitro-phenothiazine, 1,
Examples thereof include 3-dinitro-phenothiazine, 4-chloro-1-nitro-phenothiazine and the like.
Monobenzo-phenothiazine which forms an aromatic group together with two members selected from R1 to R4, as well as dibenzo which forms an aromatic group together with two members selected from R5 to R7 as disclosed in US Pat. -Benzophenothiazines such as phenothiazine. Further, similarly to the phenothiazine derivative, phenoxazine derivatives such as 3,7-dibromophenoxazine are also exemplified as the oxidatively polymerizable dye.

The oxidatively polymerizable dyes used in the present invention may be used alone or in combination of two. In this case, the hue can be changed depending on the mixing ratio. The oxidatively polymerizable dye 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 support to obtain the time indicating material of the present invention.
At this time, if the compounding amount of the oxidatively polymerizable dye is 1.0% by weight or less, the color is thin and visibility is deteriorated. Even if the blending amount is 20% by weight or more, the degree of color development does not change much,
During storage of the display material, it develops color due to air oxidation,
May not be suitable for use.

In the present invention, the oxidizing agent for polymerizing the oxidatively polymerizable dye includes metal salts, oxyacid salts, halogens, quinones, naphthoquinones, carbonyl compounds, oxides, organic peroxides, organic peracids, and peroxosulfates. Salts and nitric acid compounds. More specifically, examples of the metal salt include aluminum chloride, nickel chloride, cobalt chloride, copper chloride, iron chloride, and vanadium chloride. Examples of the oxyacid salts include nitric acid, chlorate, hypochlorite, iodate, bromate, chromate, permanganate, vanadate, bismuthate, and the like. Examples of the halogen include fluorine, chlorine, bromine, iodine, and the like.

Examples of the quinones include benzoquinone, tetrachloro-1,4-benzoquinone (chloranil), tetrachloro-1,2-benzoquinone (o-chloranyl),
2,3-dichloro-5,6-dicyano-1,4-benzoquinone and the like. As naphthoquinones, 1,
Examples thereof include 2-naphthoquinone, 1,4-naphthoquinone, 2,6-naphthoquinone, and 1,2-naphthoquinone-4-sulfonic acid. As carbonyl compounds, acetone,
Cyclohexanone and the like are used, and are used in combination with aluminum alkoxide such as aluminum butoxide. Examples of the oxide include manganese dioxide, lead dioxide, copper oxide, silver oxide, and the like.

Examples of the organic peroxide include dialkyl peroxides such as di-t-butyl peroxide, t-butyl cumyl peroxide and dicumyl peroxide, and diacyls such as acetyl peroxide, lauroyl peroxide and benzoyl peroxide. Peroxides, ketone peroxides such as methyl ethyl ketone peroxide, cyclohexanone peroxide, 3,3,5-trimethylcyclohexanone peroxide, methylcyclohexanone peroxide, 1,
Peroxy ketals such as 1-bis (t-butylperoxy) cyclohexane, t-butyl hydroperoxide, cumene hydroperoxide, 1,1,3,3-
Tetramethylbutyl hydroperoxide, p-menthane hydroperoxide, diisopropylbenzene hydroperoxide, 2,5-dimethylhexane-2,5
Hydroperoxides such as -dihydroperoxide, and peroxyesters such as t-butylperoxyacetate, t-butylperoxy-2-ethylhexanoate and t-butylperoxybenzoate. Among them, benzoyl peroxide has an excellent balance between oxidizing ability and storage stability, and is suitable as an organic peroxide-based oxidizing agent.

Examples of the organic peracid include perbenzoic acid, metachloroperbenzoic acid, monoperoxyphthalic acid, performic acid, peracetic acid, and trifluoroperacetic acid. Examples of the peroxosulfate include peroxodisulfuric acid and potassium peroxodisulfate. In addition, oxygen, ozone, chlorine, bromine, iodine, sulfur, aqua regia, nitric acid, concentrated sulfuric acid, hot concentrated perchloric acid, dimethyl sulfoxide, and the like are mentioned as the oxidizing agent in the present invention. In addition, the use of a biochemical oxidizing agent using a dehydrogenase such as dehydrogenase as the oxidizing agent of the present invention does not impose any restrictions. Among these oxidants, those with low safety are:
When used in the present invention, it is necessary to devise a constitution that does not dissolve in hot water.

The carrier used in the present invention is capable of diffusing the agent A and the agent B, that is, the oxidatively polymerizable dye and the oxidizing agent at a predetermined temperature, and maintaining the form thereof, and also capable of recognizing a color change. Any material may be used as long as it has the above transparency. Specifically, acrylic resins, polyester resins, polyether resins, polyurethane resins, silicone resins, epoxy resins, vinyl resins, etc., resins used as binders for ordinary inks and paints, and adhesives used as general adhesives Any resin may be used as long as it is a rubber-based resin, or a mixture of several types of the above resins, a ketone,
It may or may not be diluted with a commonly used solvent such as an ether, alcohol, cellosolve, petroleum, or aqueous solvent.

In particular, an adhesive rubber-based resin is advantageous in that it exhibits an adhesive function when it comes into contact with a carrier and a transparent substrate. Specifically, the adhesive rubber-based resin is a resin having a Tg of room temperature or lower, preferably -10 ° C or lower, and is desirably a rubber-like region in a temperature range during use. Examples include tacky acrylics, 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 (SIS), styrene-ethylene-butylene-styrene block copolymer (SEBS), silicone rubber, chloroprene rubber,
Examples include those used as resins for adhesives such as nitrile rubber and butadiene rubber.

Particularly, the adhesive acrylic resin can appropriately change the Tg by appropriately setting the composition and molecular weight, can control the diffusion rate of the agent A or the agent B, and It is suitable as a medium for the agent and the agent B. Adhesive acrylic resin, hydroxyl group, tertiary amino group,
It has a functional group such as a carboxyl group, an amide group, and a nitrile group, and is generally used as an acrylic resin for an adhesive. Acrylic resins having these functional groups include one or more 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,
Copolymers with monomers such as vinyl acetate, vinyl propionate, vinyl ether, and styrene.

The reaction is a usual radical polymerization, and there is no particular limitation on the reaction method, and the reaction can be carried out by a known polymerization method such as solution polymerization, bulk polymerization, emulsion polymerization, etc. Solution polymerization is preferred because it can proceed directly to the next operation. 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 organic peroxides such as benzoyl peroxide, acetyl peroxide, methyl ethyl ketone peroxide, lauroyl peroxide, and azo initiators such as azobisisobutyronitrile. Anything can be used, and there is no particular limitation.

The adhesive rubber-based resin is partially cross-linked by using a cross-linking agent such as an isocyanate and an epoxy compound to improve the adhesive property at the time of contact of the carrier and to increase the cohesive force, and to improve the cohesion of the A or B agent. The diffusion rate can be adjusted. Further, the polyurethane resin has good printability such as gravure printing, and is one of the preferable materials for the carrier from the viewpoint of the productivity of the display material. Examples of such a polyurethane resin include “Ramister R Medium”, “New LP Super”, and “LP Queen”, which are trade names of urethane resins for gravure ink manufactured by Toyo Ink Mfg. Co., Ltd.

In the carrier of the present invention, if necessary, pigments, dyes, inorganic fillers, metal powders, tackifiers, coupling agents such as silicates and titanates, defoamers, leveling agents and the like may be added. Can be. In particular, when an inorganic filler such as titanium dioxide, silica gel, or barium sulfate is added, the cohesive force of the carrier is improved, and the tack on the surface of the carrier is reduced. The effect of suppressing the diffusion rate by adsorbing and desorbing the dye is exhibited, and the effect of expanding the range of temperature-time integrated value measurement can be provided.

In the present invention, any method can be used to change the agent A and the agent B from the non-contact state to the contact state. For example, the layer containing the agent A and the layer containing the agent B are separated. There is a method in which a tape provided on the base material is prepared, and these two tapes are bonded immediately before heating such that the agent A and the agent B face each other. Also, as another method, A
The layer containing the agent and the layer containing the agent B are laminated with a layer made of a thermoplastic resin having appropriate thermal characteristics such as Tg as a diaphragm layer, and heated to form the agent A and / or Examples of the method include a method in which the agent B is diffused so that the two components come into contact with each other, and a method in which the agent A or the agent B is microencapsulated and the capsule is broken by heating during use to make contact.

Examples of the transparent substrate include olefin films such as polyethylene and polypropylene, polyester films such as polyethylene terephthalate, cellophane, polyvinylidene chloride, polyvinylidene chloride copolymer, polyvinylidene fluoride, polyvinyl chloride, and nylon. And plastic films such as 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. Further, even if these substrates are laminated, they can be used in the present invention as long as they have such transparency that a change in hue can be confirmed.

Further, as the food packaging base material, a film of an olefin resin such as polyethylene or polypropylene having heat adhesion and moisture resistance can be used. In addition, an olefin resin, cellophane, nylon, polyethylene terephthalate, polyvinylidene chloride, aluminum foil, a film such as paper, laminated layers of ethylene-vinyl alcohol resin, ethylene-vinyl acetate resin, polyvinyl alcohol resin and the like, A composite film having improved light blocking properties, gas transmission blocking properties, oil resistance, and impact resistance can also be used.

In the present invention, the color sample for judging the heating temperature-time printed on the transparent substrate or the food packaging substrate is defined as a color hue that changes with time when the agent A and the agent B are brought into contact. In comparison, any material can be used as long as it can determine how much heat is given to the food. As an example of a method of determining that a predetermined amount of heat has been applied, a hue when a predetermined amount of heat is applied is previously confirmed, and an ink having exactly the same hue as the hue is prepared. There is a method of printing on a transparent substrate or a food packaging substrate on which the agent B is laminated. With this method, it is possible to determine that a predetermined amount of heat has been applied when the hue of the color change between the printing layer and the display material of the present invention becomes the same.

The printing pattern may be any as long as it can be compared with the hue of the display material of the present invention, which changes over time. For example, patterns such as stripe printing, polka dot printing, and logo printing are exemplified. By providing the printing of the determination color, the visual accuracy of the optimum heating time is improved. Further, when the printing of the determination color is not performed on the base material, the hue at the time of optimal heating is confirmed in advance, and a reference hue sample reproducing the same hue by printing or the like is displayed according to the present invention. If it is made separately from the material, the accuracy of the determination of the optimal heating time is further improved. The method of providing the pattern printing and the reference color sample for determining the heating temperature-time as described above may be any ordinary printing method such as gravure printing, offset printing, silk screen printing, flexographic printing, etc. It is not something to be done.

In the present invention, the method of providing the layer containing the agent A and the layer containing the agent B on a transparent substrate or a food packaging substrate is not particularly limited, and any coating and printing methods generally used can be used. A method may be used. Examples of the coating method include a comma coater, a lip coater, a die coater, a doctor blade and the like. Examples of the printing method include silk screen printing, gravure printing, offset printing, and flexographic printing. In addition, it is also possible to use a system such as ink jet or thermal transfer.

The display material of the present invention can be provided with a member to be attached to a food packaging material. Examples of the member include a jig such as an adhesive for attaching the display material of the present invention to the food packaging material, a clip for fixing, and the like, which are separated from the food packaging material during heating in hot water. If not, any member may be provided. The position where the display material of the present invention is attached to the food packaging material is not particularly limited. Since an ordinary food packaging material often has a heat seal portion for sealing the contents at the end, it is preferable to attach the heat seal portion to the heat seal portion. By being attached to the heat-sealed portion, the influence of temperature unevenness due to convection of the food inside the food packaging material is reduced, and the amount of heat applied to the food can be displayed more accurately as a color change.

The food packaging material to which the display material of the present invention is attached is not particularly limited in terms of the material, structure, thickness, shape, etc. It is preferable to secure a relatively large space because the workability at the time of attachment is improved. The ingredients inside the food packaging are not particularly limited,
Any food may be used. More specifically, soups such as corn cream, sauces used for spaghetti and hamburgers, foods containing relatively large ingredients such as curries and stews, solid ingredients such as hamburgers and meatballs, parent and child Rice bowls such as rice bowls and beef bowls, rice such as porridge and rice balls.

[0039]

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

(Production Example of Resin 1) Butyl acrylate 94.1 parts Acrylic acid 5.9 parts Azobisisobutyronitrile 0.2 parts Ethyl acetate 150.0 parts Heated to 80 ° C. in a nitrogen atmosphere using a flask as a reaction vessel. To 125 parts of the above-mentioned mixture of each composition, 125 parts of the above-mentioned mixture of the same composition was dropped, and after completion of the dropping, the mixture was heated to reflux for 12 hours, cooled, and a solution of resin 1 (solid content 40%).
I got

(Production Example of Resin 2) Methyl acrylate 100.0 parts Azobisisobutyronitrile 0.2 parts Ethyl acetate 150.0 parts Each of the above compositions heated to 80 ° C. in a nitrogen atmosphere using a flask as a reaction vessel. 125 parts of the above-mentioned mixture of the same composition is dropped into 125 parts of the above mixture, and after completion of the dropping, the mixture is heated under reflux for 12 hours, cooled, and a solution of resin 2 (solid content 40%)
I got

In the following examples, a food packaging material 1 (Oyako-don bowl) in which foods requiring heating at 98 ° C. for 5 minutes were sealed was used. The food packaging material 1 has a heat seal portion generated when sealing the food.

Example 1 100 parts of a solution of Resin 2 and 12 parts of a 10% ethyl acetate solution of phenothiazine were mixed with stirring to obtain a 50 μm-thick polyethylene terephthalate (P).
ET) Apply to the film with a doctor blade, 9
The resultant was dried by heating at 0 ° C. for 2 minutes to obtain a layer A1 containing the agent A having a thickness of 24 μm. A white pressure-sensitive adhesive was applied to the PET substrate provided with the layer A1 containing the agent A on the side opposite to the side provided with A1, so as to have a thickness of 25 μm. Next, 100 parts of the resin 2 solution and 2.4 parts of t-butyl peroxybenzoate were stirred and dispersed and mixed, applied to a PET film by a doctor blade, and dried by heating at 90 ° C. for 2 minutes to form a film having a thickness of 24 μm.
The layer B1 containing the agent B was obtained. Layers A1 and B containing the agent A
After the layer B1 containing the agent was adhered face to face and brought into contact with the display material 1, the white pressure-sensitive adhesive layer was adhered to the heat-sealed portion of the food packaging material 1. Further, the hue when the display material obtained in this example was actually heated at 98 ° C. for 5 minutes was confirmed in advance, and a reference hue sample in which the same hue was reproduced by toning and printing of ink was prepared. did.

Example 2 100 parts of the resin 2 solution
-10% solution of methoxyphenothiazine in ethyl acetate 12
And the mixture was stirred and mixed, coated on a PET film by a doctor blade, and dried by heating at 90 ° C. for 2 minutes to form a film having a thickness of
A layer A2 containing μm agent A was obtained. Layer A2 containing agent A
A white pressure-sensitive adhesive was applied on the side opposite to the side on which A2 was provided on the PET substrate provided with so as to have a thickness of 25 μm. Next, 100 parts of the solution of the resin 2 and 2.4 parts of t-butyl peroxybenzoate were stirred and dispersed and mixed to obtain the same hue as that of the display material obtained in this example in advance at 98 ° C. for 5 minutes. It was applied on a PET film on which a stripe pattern was printed using the toned ink using a doctor blade, and was heated and dried at 90 ° C. for 2 minutes to obtain a layer B2 containing a B agent having a thickness of 25 μm. After the layer A2 containing the agent A and the layer B2 containing the agent B were brought into contact with each other to form the display material 2, a white pressure-sensitive adhesive was adhered to the heat-sealed portion of the food packaging material 1.

Example 3 100 parts of the solution of the resin 1 and 12 parts of a 10% ethyl acetate solution of phenothiazine were mixed by stirring, applied on a PET film by a doctor blade, and dried by heating at 90 ° C. for 2 minutes to form a film. The layer A3 containing the agent A having a thickness of 25 μm was obtained. Next, an ethyl acetate solution of an acrylic resin having a Tg of 30 ° C. was applied to PET having been subjected to mold release surface treatment using a doctor blade, and dried at 90 ° C. for 2 minutes to form a thermoplastic resin layer 1 having a thickness of 10 μm. After laminating this thermoplastic resin layer 1 so as to face the layer A3 containing the agent A, the release treatment PET used when applying the thermoplastic resin layer 1 was peeled off. Next, 100 parts of the solution of the resin 1 and 12 parts of 2,5-dimethyl-2,5-di (m-toluylperoxy) hexane were stirred and dispersed and mixed. A doctor blade is applied on a PET film on which a stripe pattern has been printed using an ink toned to the same hue as that after 5 minutes, and dried by heating at 90 ° C. for 2 minutes to form a 25 μm-thick B film. A layer B3 containing the agent was obtained. The layer B3 containing the agent B was bonded to the thermoplastic resin layer previously laminated so as to face the thermoplastic resin layer, thereby obtaining a display material 3. A white adhesive was applied in a thickness of 25 μm to the PET film on the layer containing the agent A of the display material 3 and attached to the heat-sealed portion of the food packaging material 1.

Example 4 100 parts of a solution of the resin 1 and 12 parts of a 10% ethyl acetate solution of phenothiazine were mixed by stirring, applied on a PET film by a doctor blade, and dried by heating at 90 ° C. for 2 minutes to form a film. A layer A4 containing the agent A having a thickness of 25 μm was obtained. Next, 100 parts of the resin 1 solution was mixed with silica fine powder (“AEROZIL20” manufactured by Nippon Aerosil Co., Ltd.).
0 ") After dispersing 4 parts, the mixture was stirred and dispersed and mixed with 2.4 parts of t-butyl peroxybenzoate, and the mixture was applied on a release-treated surface-treated PET film by a doctor blade.
The film was dried by heating at 90 ° C. for 2 minutes to obtain a layer B4 containing a B agent having a thickness of 25 μm. The layer A4 containing the agent A and the layer B containing the agent B
After bonding and contacting each other so as to face each other, the PET film used when applying the B4 layer was peeled off to obtain a display material 4. The surface of the layer B4 containing the agent B of the display material 4 was attached to the heat-sealed portion of the food packaging material 1. Further, the hue when the display material obtained in this example was actually heated at 98 ° C. for 5 minutes was confirmed in advance, and a reference hue sample in which the same hue was reproduced by toning and printing of ink was prepared. did.

Example 5 100 parts of the resin 1 solution and 12 parts of a 10% ethyl acetate solution of phenothiazine were stirred and mixed, and the mixture was applied to a release-treated surface-treated PET film by a doctor blade. The film was heated and dried for 2 minutes to obtain a layer A5 containing the agent A having a thickness of 25 μm. Next, 4 parts of silica fine powder (“AEROSIL200” manufactured by Nippon Aerosil Co., Ltd.) was dispersed in 100 parts of the resin 1 solution, and then t-
2.4 parts of butyl peroxybenzoate was stirred and dispersed and mixed, applied to a PET film by a doctor blade, and dried by heating at 90 ° C. for 2 minutes to obtain a layer B5 containing a B agent having a thickness of 25 μm. The layer A5 containing the agent A and the layer B5 containing the agent B are bonded to face each other and brought into contact with each other so that the display material 5
And PET on layer B5 side of this display material 5 containing agent B
A white adhesive was applied to the film so as to have a thickness of 25 μm, and the film was attached to the heat-sealed portion of the food packaging material 1. Further, the hue when the display material obtained in this example was actually heated at 98 ° C. for 5 minutes was confirmed in advance, and a reference hue sample in which the same hue was reproduced by toning and printing of ink was prepared. .

(1) Change in hue upon heating at 98 ° C. The display materials obtained in Examples 1 to 5 were placed in a hot water bath at a constant temperature of 98 ° C., and the changing hue was visually observed. The results are shown in Table 1. (2) Heating time at a constant temperature of 98 ° C. The food packaging material obtained in Examples 1 to 5 was put into a hot water bath at a constant temperature of 98 ° C., and 5 minutes were determined without judging from the clock and judging from the hue of the display material. At the time when it seems that the time has passed, pull out the food packaging material from the hot water bath, check the time spent in the hot water bath, check the actual taste of each food material and make sure that it is sufficiently heated. This was repeated 10 times. For Examples 1, 4 and 5, by comparing the hue with the reference color sample, and for Examples 2 and 3, by comparing the hue with the color sample printed on the base material, when the values become equivalent, Determined the time to raise. The results are shown in Table 2.

(3) Optimum heating time under a temperature fluctuating from 95 ° C. to 96 ° C. The food packaging material obtained in Examples 1 to 5 was heated at a specified temperature (9
8 ° C), which is placed in a hot water bath that fluctuates between 95 ° C and 96 ° C, and without looking at the clock, judging from the hue of the display material, at the time when it seems that the optimal amount of heat has been applied, the food packaging The operation of withdrawing the ingredients from the hot water bath, checking the time spent in the hot water bath, checking the actual taste of each food material, and confirming that sufficient heat was passed was repeated 10 times.
The comparative example was pulled out of the hot water with an approximate time sense without looking at the clock. For Examples 1, 4, and 5, the hue was compared with the reference color sample, and for Examples 2 and 3, the hue was compared with the color sample printed on the base material. Judge the time. The results are shown in Table 3.

[0050]

[Table 1]

[0051]

[Table 2]

[0052]

[Table 3]

According to the present invention, information on the heating time at a predetermined temperature and the time at which the optimal amount of heat is applied under a fluctuating temperature can be obtained in a clear hue without using a device such as a thermometer or a timer. The change has made it cheaper to obtain.

[0053]

[Brief description of the drawings]

FIG. 1 is a mass spectrometry spectrum of a display material of Example 1 at an early stage of a reaction.

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Yasunori Kimura 2-3-13 Kyobashi, Chuo-ku, Tokyo Toyo Ink Manufacturing Co., Ltd.

Claims (5)

[Claims] 1. A layer comprising the following agent A supported on a carrier and a layer containing the following agent B in a non-contact state with the agent A. A display material that controls the optimal heating temperature and time for cooking as a color change by polymerizing pigments. However, the A agent and the B agent consist of a combination of an oxidatively polymerizable dye and an oxidizing agent. 2. A resin layer laminated on a transparent substrate on which a color sample for judging heating temperature-time is printed, wherein the layer containing the agent A and / or the layer containing the agent B are printed. Display material. 3. The display material according to claim 1, further comprising a member attached to a food packaging material. 4. A food packaging material obtained by laminating the display material according to claim 1 on a food packaging substrate. 5. The food packaging material according to claim 4, wherein a color sample for determining the heating temperature-time is printed on the food packaging substrate.