JPH1114616A - Time indicator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable stably indicating elapsed time, by laminating a specified oxygen gas permeation control layer which is scarcely affected by environmental change (temperature and moisture), on a discoloration layer whose color is changed by reaction with oxygen. SOLUTION: A discoloration layer containing compound whose color is quickly changed by reaction with oxygen is laminated on the single side or both sides of a base body. An oxygen gas permeation control layer whose oxygen gas permeability is 0.1-3,000 ml/m<2> .24 hr.atm.25 deg.C.100% RH is laminated on the discoloration layer. As the base body, a plastic film, sheet, plate, a metal foil such as an aluminum foil, paper, unwoven fabric, and cloth and compound of them are used. As the plastic, the following are used; polyethylene terephthalate, polyethylene-2,6-naphthalate, polyethylene, polypropylene, nylon, polyvinyl chloride, polyvinylidene chloride, saponified ethylene-vinylalcohol copolymer, ethylene vinyl acetate copolymer, polystyrene, polycarbonate, norbornane, etc.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a time indicator which changes its color by reaction with oxygen and indicates the passage of time.

[0002]

2. Description of the Related Art In recent years, various methods have been studied as methods for indicating the expiration date of a product. For example, there is a method in which the volatility of a substance is used and the degree of coloring is reduced by volatilization of a coloring liquid (including those absorbed in a gel) or volatilization of a sublimable dye. However, the volatilization of the substance is greatly affected by the temperature and the humidity, so that it is difficult to indicate an accurate period, and the volatile substance may contaminate the surrounding air. Also,
A time indicator indicating the elapsed time may be considered by a color change due to light, temperature, humidity, or a gas such as oxygen gas or carbon dioxide gas in the atmosphere. However, since light, temperature, humidity, etc. change greatly in daily life, the time indicator using them may cause a color change before the scheduled period elapses, or the color may change even after the scheduled period elapses. It may not change, and it is difficult to stably represent the elapsed time.

On the other hand, Japanese Patent Application Laid-Open No. 58-210564 discloses an oxygen indicator using bis (salicylaldehyde) alkylenediiminecobalt (II) or a derivative thereof. Also, Japanese Patent Application Laid-Open No. 64-1017
No. 2 discloses an oxygen indicator sheet comprising a coating film of a high molecular amine cobalt complex and a thermoplastic coating layer. However, these are oxygen indicators that change color depending on the presence or absence of oxygen in the closed packaging container, and a realistic and accurate time indicator could not be obtained.

[0004]

SUMMARY OF THE INVENTION An object of the present invention is to provide a time indicator which changes its color due to the reaction with oxygen and stably indicates an accurate elapsed time.

[0005]

Means for Solving the Problems The inventors of the present invention control the permeation of oxygen gas on a discoloration layer which discolors by reaction with oxygen, without being affected by environmental changes (temperature and humidity). The inventors have found that by laminating the layers, a time indicator stably indicating the elapsed time can be obtained, and have reached the present invention. That is, according to the present invention, a color-changing layer containing a compound that rapidly changes color by reaction with oxygen is laminated on one or both surfaces of a substrate, and an oxygen gas permeability of 0.1 is formed on the color-changing layer.
The present invention relates to a time indicator comprising an oxygen gas permeation control layer of 1 to 3000 ml / m ² · 24 hr · atm · 25 ° C. · 100% RH.

Further, according to the present invention, an oxygen gas permeability of 0.1 to 3000 ml / m ^{2 is} provided on the surface of the substrate on which the discoloration layer is not laminated.
The present invention relates to the above-mentioned time indicator, wherein an oxygen gas permeation control layer of 24 hr, atm, 25 ° C., 100% RH is laminated. The present invention also relates to the time indicator, wherein the oxygen gas permeation control layer includes a layer composed of an inorganic substance. In addition, the present invention, the inorganic substance,
The present invention relates to the above time indicator, which is one or more compounds selected from silicon oxide, aluminum oxides, magnesium oxides, and metal fluorides. In the present invention, the compound which rapidly changes color by reaction with oxygen is selected from bis (salicylaldehyde) alkylenediiminecobalt (II), bis (orthohydroxyacetophenone) alkylenediiminecobalt (II) and derivatives thereof. The time indicator according to claim 1, wherein the time indicator is at least one cobalt complex.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION As a substrate, polyethylene terephthalate, polyethylene-2,6-naphthalate, polyethylene, polypropylene, nylon, polyvinyl chloride,
Plastic films, sheets and plates such as polyvinylidene chloride, saponified ethylene-vinyl alcohol copolymer, ethylene-vinyl acetate copolymer, polystyrene, polycarbonate, norbornene, metal foils such as aluminum foil, paper , A nonwoven fabric, a cloth, or a combination thereof can be used. The compounding can be performed by a method using an adhesive or a method of hot-melting and compounding. Among the substrates, the plastic film or sheet may be a heat-fixed film or sheet such as a uniaxially stretched film or a biaxially stretched film.

It is preferable that nothing is provided on the surface of the base, but an anchor coat resin such as a polyurethane resin, a polyester resin, a polyether resin, an acrylic resin, a butadiene resin, a polyethyleneimine resin, and an alkyl titanate is preferably used. It may be provided. Further, in order to improve the adhesion of the discoloration layer or the oxygen gas permeation control layer, the substrate may be subjected to a corona treatment, a plasma treatment, a frame treatment or the like. In particular, when an aluminum foil or a white-colored opaque film is used as the substrate, a change in color according to the oxygen concentration can be clearly observed, which is preferable as compared with a case where a transparent film is used. .
The thickness of the substrate is not particularly limited, but is suitably 6 to 100 μm.

On one or both sides of the substrate, a color-change layer containing a compound which changes color rapidly by reaction with oxygen, preferably within one hour, is laminated. Specific examples of the compound that rapidly changes color upon reaction with oxygen include bis (salicylaldehyde) alkylenediiminecobalt (II) and its derivatives, bis (orthohydroxyacetophenone)
Alkylenediimine cobalt (II) and derivatives thereof,
Oxidation-reduction dyes that exhibit different colors of oxidized and reduced forms in the coexistence of biologens, redox indicators, reduced saccharides and alkaline substances. Examples of the redox dye include a thiazine dye, an indigo dye, a thioindigo dye, a sulfur dye, and the like, and these can be used in combination of two or more.

In the case of combining two or more kinds of compounds that rapidly change color by reaction with oxygen, they may be used as a solid solution having a crystal structure different from that of each single component, in addition to a mixture of two or more kinds. Bis (salicylaldehyde) alkylenediiminecobalt (II) and its derivatives, and bis (orthohydroxyacetophenone)
Alkylenediimine cobalt (II) and its derivatives are deep dark green in an inactivated state (oxygen-absorbed) and turn yellow in an activated state (oxygen-absorbed). Methylene blue (thiazine dye), which is a typical example of a redox dye, changes from colorless to blue.

The alkylenediimines of bis (salicylaldehyde) alkylenediiminecobalt (II) and bis (orthohydroxyacetophenone) alkylenediiminecobalt (II) include ethylenediimine, hexamethylenediimine and 3,3-diimino. -Di-n-propylamine, etc., and the derivative is a hydrogen atom as a halogen atom,
It is substituted by an alkyl group, an alkoxy group, a nitro group, or the like. It is preferable to activate the cobalt complex because the activity of the cobalt complex as it is is weak or shows no activity at all. By activating, sufficient sensitivity to oxygen can be obtained for use in the time indicator of the present invention. As a method for activating the cobalt complex, (1) heating the powder,
Immediately after sublimation, it is cooled and reprecipitated (sublimation treatment),
There are methods such as (2) pulverization, (3) removal of pyridine by heating and degassing after immersion in pyridine,
By the method (3), a cobalt complex having particularly high sensitivity to oxygen can be obtained.

A mixture of two or more types of cobalt complexes can be obtained simply by intimately mixing them in a powder state, but a mixture of two or more types selected from salicylaldehyde, orthohydroxyacetophenone and derivatives thereof is used. It can also be obtained by a method of refluxing with an alkylene diamine and a cobalt salt such as cobalt acetate and cobalt nitrate in an alcohol solvent such as ethanol. In addition, a hot water solution containing a mixture of two or more selected from bis (salicylaldehyde) alkylenediimine, bis (orthohydroxyacetophenone) alkylenediimine and derivatives thereof, sodium acetate and sodium hydroxide is used to prepare cobalt (II) chloride. ) Can also be obtained by adding aqueous solutions.

The desired intimately mixed mixture of cobalt complexes can also be obtained by the activation operation. For example, a treatment operation (1), (2),
Alternatively, by performing (3), a mixture of activated cobalt complexes is obtained. The composition ratio of the cobalt complex is not particularly limited, but when two types are mixed, the molar ratio is 10%.
/ 1 to 1/10 are preferred.

As a method of laminating the color changing layer on the substrate,
(1) A method of printing or coating a printing ink or paint containing a compound that rapidly changes color by reaction with oxygen on a substrate, and (2) Deposition or sputtering of a compound that rapidly changes color by reaction with oxygen on the surface of the substrate. Method. Printing inks and paints used for lamination of the color-changing layer are added with a resin that becomes a binder to a compound that rapidly changes color by reaction with oxygen, and a pigment for obtaining a desired hue change, if necessary, usually, In the presence of a solvent, dispersion can be carried out using an impact-type disperser such as a sand mill or an attritor or a shear-type disperser such as a kneader or a roll. In this dispersion step,
Compounds that change color rapidly upon reaction with oxygen are ground more finely, resulting in a significant increase in surface area and a more sensitive response to oxygen.

Examples of resins used as binders for printing inks and paints include natural resins such as natural rubber, shellac, fibers, proteins, rosin, polyvinyl chloride, and the like.
Polyvinylidene chloride, polyvinyl acetate, vinyl chloride-vinyl acetate copolymer, polyvinyl alcohol, polystyrene, polybutadiene, acrylic resin, chloride rubber, phenol resin, cellulose derivative, chlorinated polypropylene, ethylene-vinyl acetate copolymer, melamine Resin, epoxy resin, urethane resin, synthetic resin such as unsaturated polyester resin, and the like.

The above resin can be used by freely selecting one or two or more kinds according to the kind of the substrate and, if necessary, depending on the kind, hue, coloring power, width of discoloration, and the like.
Response speed is slightly different. The printing ink or paint obtained by the above method can be printed or coated on a substrate by various printing or coating methods such as a gravure method, an offset method, a silk screen method, a roll coating method, and a spray method. From the viewpoint of oxygen permeability, gravure printing and offset printing, which can form a thin film, are advantageous.

The lamination of the color-change layer by vapor deposition or sputtering can be carried out by drying the compound which rapidly changes color by reaction with oxygen and then vapor-depositing or sputtering the substrate surface, preferably under reduced pressure. In this case, either a continuous winding method or a single-wafer method may be used, and the heating method for vacuum deposition is such that vapor deposition droplets called "splash" do not occur during the vapor deposition or are small enough to remove them without any trouble. There is no particular limitation, and a known heating method such as high-frequency induction heating, resistance heating, and electron beam heating can be used. In addition, a general crucible method or a boat method may be used as an evaporation source for vacuum deposition. A compound that changes color rapidly by reacting with oxygen by vapor deposition or sputtering on the surface of the substrate becomes extremely sensitive to color change because the activity against oxygen increases.

On the discoloration layer, an oxygen gas permeability of 0.1 to
An oxygen gas permeation control layer of 3000 ml / m ² · 24 hr · atm · 25 ° C · 100% RH is laminated. In the present invention, the oxygen gas permeability is 100 ml / m ² · 24 hr · atm · 2
When the temperature is lower than 5 ° C. and 100% RH, it is measured by an equal pressure method specified in ASTM D3985. Also,
Oxygen gas permeability ^{100ml / m 2 · 24hr · atm} · 25 ℃ · 100
In the case of% RH or more, it is measured according to ASTM D 1434.

The oxygen gas permeation control layer is composed of one layer or two or more layers composed of an inorganic substance or an organic substance. The oxygen gas permeation rate is less dependent on changes in environment (temperature and humidity) and has transparency. It is preferable to include a layer composed of an inorganic substance. The small dependence of the oxygen gas permeability on changes in the environment (temperature and humidity) means that the change in the oxygen gas permeability of the oxygen gas permeation control layer is very small even when the environment changes, and the oxygen gas permeation through the oxygen gas permeation control layer is very small. This means that the amount of oxygen produced is constant, and the resulting time indicator can accurately represent time.

The oxygen gas permeation control layer including a layer composed of an inorganic substance may be composed of only a layer composed of an inorganic substance, and a layer composed of an organic substance (base substrate) may be formed by a vacuum thin film forming method. It may be a laminate having a layer made of an inorganic material. As a method of forming a vacuum thin film, there are various methods such as vacuum deposition, sputtering, ion plating and the like.
A method called VD or CVD can be used. The oxygen gas permeation control layer consisting only of a layer composed of an inorganic substance can be directly laminated on the discoloration layer by using a vacuum thin film forming method. Further, the oxygen gas permeation control layer composed of a laminate including a layer composed of an inorganic substance can be laminated on the color-change layer by being attached to the color-change layer. The method of forming a vacuum thin film in which a layer composed of an inorganic substance is provided on a base material may be either a continuous winding method or a single-wafer method.

The oxygen gas permeation control layer is one or more selected from silicon oxides, aluminum oxides, magnesium oxides and metal fluorides in terms of stability and transparency of the oxygen gas permeability against environmental changes. It is preferable to include a layer composed of two or more inorganic substances. The thickness of the layer composed of an inorganic substance is selected depending on the desired oxygen gas permeability, but is preferably 10 to 500 nm, particularly 20 to 200 nm.
nm is preferred. Silicon oxide is SiOx (X = 1.
5 or more and less than 2). In particular, SiOx in which X is greater than 1.8 and less than 2.0 is preferable because of high light transmittance. SiOx where X is 1.8 or less exhibits a slightly brown color. SiOx in which X is less than 1.5 completely turns brown and lowers the visibility of the discoloration layer, and is therefore unsuitable as an oxygen gas permeation control layer laminated on the discoloration layer.

Examples of the aluminum oxides include aluminum oxide, a co-oxide of aluminum oxide and silicon dioxide (a co-oxide called mullite), and a composite compound of aluminum oxide and metal fluoride. Magnesium oxides include magnesium oxide, a co-oxide of magnesium oxide and silicon dioxide, specifically, forsterite (SiO ₂ · 2MgO) or steatite (2SiO ₂ · MgO), magnesium oxide and metal fluoride. And a composite compound of Examples of the metal fluoride include magnesium fluoride and calcium fluoride.

The layer composed of an organic substance includes polyvinyl alcohol, saponified ethylene-vinyl alcohol copolymer, polyethylene terephthalate, polyethylene-2,6-naphthalate, polyethylene, polypropylene,
Plastic films such as nylon, polyvinyl chloride, polyvinylidene chloride, ethylene-vinyl acetate copolymer, polystyrene, polycarbonate, norbornene, polyacrylonitrile, triacetylcellulose, cellophane, polyurethane, fluororesin, and polyimide are listed. Can be The thickness of the layer made of an organic substance is not particularly limited, but is suitably 6 to 100 μm.

When a layer composed of an organic substance is used as a base substrate, there is no particular limitation as long as it can be used for forming a vacuum thin film, and the film is heat-fixed such as a uniaxially stretched film or a biaxially stretched film. Film. It is preferable that nothing is applied to the surface of the layer composed of an organic substance, but an organic conductive agent such as a surfactant or a polymer electrolyte or an inorganic conductive agent such as a conductive metal oxide is coated in advance. Or an organic barrier layer such as polyvinylidene chloride, polyvinyl alcohol, or the like.

For example, oxygen gas permeability 0.1 / m ² · 24 hr
The oxygen gas permeation control layer of atm, 25 ° C. and 100% RH is obtained by co-evaporating a silicon oxide and a metal fluoride to a thickness of about 100 nm on a polyethylene terephthalate film. In addition, oxygen gas permeability 3,000
/ m ²・ 24hr ・ atm ・ 25 ℃ ・ 100% RH
It is obtained by vapor deposition so as to have a thickness of about 0 nm.

The oxygen gas permeation control layer composed of a single layer or a laminate of two or more layers composed of an organic substance, or a laminate including a layer composed of an inorganic substance may be bonded using an adhesive, a melt extrusion coating method, or the like. It is laminated on the discoloration layer by a heat sealing material coating method, a method of laminating a heat fusible film on one side and then a thermal laminating method. The most preferred lamination method of the oxygen gas permeation control layer is
This is a method in which silicon oxide is vacuum-deposited on a plastic film, and the obtained vacuum-deposited film is dry-laminated with a heat-fusible film, and then thermally laminated on the color-change layer.

The substrate has an appropriate oxygen gas permeability (0.1 to 3).
If the ^{000ml / m 2 · 24hr · atm} · 25 ℃ · 100% RH) does not have a can on a surface discoloration layer of the substrate is not laminated,
Oxygen gas permeability ^{0.1~3000ml / m 2 · 24hr · atm} ·
An oxygen gas permeation control layer at 25 ° C and 100% RH is laminated. The two oxygen gas permeation control layers may be the same or different. In particular, when a color-change layer containing bis (salicylaldehyde) alkylenediiminecobalt (II) or a derivative thereof is laminated on one surface of the substrate, the surface on which the color-change layer is not laminated is made of a metal foil such as aluminum. An oxygen gas permeation control layer may be laminated. When the time indicator of the present invention is processed into a film or a sheet, the time indicator can be freely cut and used, and the cut one can be sealed in a film and used.

[0028]

EXAMPLES Hereinafter, the present invention will be described in more detail based on examples, but the present invention is not limited to the following examples. In addition, the test method in an Example is as follows. Oxygen gas barrier property measurement: ・ Oxygen gas permeability is 100ml / m ²・ 24hr ・ atm ・ 25 ℃ ・ 1
In the case of less than 00% RH, OXTRAN-TW manufactured by Modern Controls of the United States conforms to ASTM D3985.
Oxygen gas permeability was measured using IN.・ Oxygen gas permeability is 100ml / m ²・ 24hr ・ atm ・ 25 ℃ ・ 1
In the case of more than 00% RH, the oxygen gas permeability was measured according to ASTM D 1434. Time indicator test:-Starting from the time when the time indicator was created, 25
Under an environment of 50 ° C. and 50% RH and an environment of 35 ° C. and 90% RH, the time until the color changed to a predetermined color was measured. Confirmation of the default color was made visually.

Example 1 A 100 μm-thick white polyethylene terephthalate film (“Melinex 329” manufactured by ICI) was screwed on one side using a crucible type continuous winding resistance heating type vacuum evaporation machine. Using (lid) ethylenediiminecobalt (II) as a raw material, heating and vacuum deposition were performed (thickness: about 10 nm), and a discoloration layer was laminated. Next, a continuous winding type resistance heating type vacuum evaporator described in Japanese Patent Application Laid-Open No. 1-252786 was used, which continuously supplies and discharges the evaporation raw material to one side of a colorless polyethylene terephthalate film having a thickness of 12 μm. After heating and vacuum-depositing (a thickness of about 100 nm) a mixture of silicon, silicon dioxide and magnesium fluoride (mixing ratio: 45 mol%: 45 mol%: 10 mol%), no inorganic vapor deposition layer is provided. A polyethylene film having a thickness of 40 μm is adhesively bonded to the surface (“AD8 manufactured by Toyo Morton Co., Ltd.
17 ") to obtain a laminate (oxygen gas permeation control layer). When the oxygen gas barrier property of the obtained laminate was measured, it was 0.1 ml / m ² · 24 hr · atm · 25
° C and 100% RH. After heating the white polyethylene terephthalate film on which the discoloration layer is laminated to 80 ° C.,
Sandwiched between the two laminates so that the polyethylene film surface is in contact with the surface where the discoloration layer and the discoloration layer are not laminated,
Thermal lamination was performed at 140 ° C. to obtain a time indicator.

Example 2 A substrate having a thickness of about 10 in the same manner as in Example 1 was formed on one side of a substrate prepared by dry laminating polyethylene terephthalate (25 μm) / aluminum foil (9 μm) / polyethylene terephthalate (25 μm).
A color change layer of nm was laminated. The oxygen gas barrier property of the substrate was 0.0 ml / m ² · 24 hr · atm · 25 ° C. · 100% RH. Next, on one side of a 60 μm polyethylene film,
Using the same vacuum deposition machine as in Example 1, a mixture of silicon, silicon dioxide and magnesium oxide (mixing ratio: 45 mol%:
(45 mol%: 10 mol%) as a raw material and heated under vacuum (thickness: about 10 nm) to form a laminate (oxygen gas transmission control layer)
I got When the oxygen gas barrier property of the obtained laminate was measured, it was 1000 ml / m ² · 24 hr · 25 ° C. · 100% RH. The laminate was overlaid so that the polyethylene film surface was in contact with the discoloration layer, and was thermally laminated at 120 ° C. to obtain a time indicator.

Example 3 Bis (orthohydroxyacetophenone) ethylenediiminecobalt (II) activated with pyridine was dispersed in a sand mill together with a gravure printing varnish using a vinyl chloride-vinyl acetate copolymer as a binder. Thus, a gravure ink having a content of the cobalt complex of 10% by weight was obtained. Gravure ink was gravure-printed on both sides of the high-quality paper so as to have a film thickness of 10 μm, and a discoloration layer was laminated. Next, one side of 12 μm colorless polyethylene terephthalate was heated and vacuum-deposited (thickness: about 100 nm) using aluminum oxide as a raw material by using an electron beam heating-type vacuum deposition apparatus, and then a surface on which an inorganic substance deposition layer was provided. Then, a polyethylene film having a thickness of 40 μm was dry-laminated using an adhesive (“AD817” manufactured by Toyo Morton Co., Ltd.) to obtain a laminate (oxygen gas permeation control layer). When the oxygen gas barrier property of the obtained laminate was measured, it was 1.0 ml / m ² · 24 hr · atm · 25 ° C. · 100% RH. After heating the high quality paper on which the discoloration layer is laminated to 80 ° C.,
The laminate was sandwiched between two laminates so that the polyethylene film surface was in contact with the discoloration layer, and was thermally laminated at 140 ° C. to obtain a time indicator.

Example 4 Bis (orthohydroxyacetophenone) ethylenediiminecobalt (II) activated with pyridine was dispersed in a sand mill together with a varnish for gravure printing using nitrocellulose and a polyamide resin as a binder. A gravure ink having a cobalt complex content of 10% by weight was obtained. A gravure ink was gravure-printed to a thickness of 10 μm on the surface of a 25 μm-thick corona-discharge-treated white polyethylene terephthalate film, and a color change layer was laminated. Next, a 12 μm colorless polyethylene terephthalate and a 40 μm thick polyethylene film were bonded with an adhesive (“AD81 manufactured by Toyo Morton Co., Ltd.”
7)) to obtain a laminate (oxygen gas permeation control layer). When the oxygen gas barrier property of the obtained laminate was measured, it was 100 ml / m ² · 24 hr · atm · 25
° C and 100% RH. After heating the white polyethylene terephthalate film on which the discoloration layer was laminated to 80 ° C., it was sandwiched between two laminates so that the polyethylene film surface was in contact with the discoloration layer, and was thermally laminated at 140 ° C. to obtain a time indicator.

Example 5 Methylene blue (redox dye), fructose (reduced saccharide) and magnesium hydroxide (alkaline substance) were dispersed in a sand mill together with a varnish for gravure printing using nitrocellulose and a polyamide resin as a binder. A gravure ink having a methylene blue content of 1% by weight was obtained. A gravure ink was gravure-printed to a thickness of 10 μm on the surface of a 25 μm-thick corona-discharge-treated white polyethylene terephthalate film, and a color change layer was laminated. Next, one side of 12 μm colorless polyethylene terephthalate was heated and vacuum-deposited (thickness: about 100 nm) with aluminum oxide as a raw material using an electron beam heating-type vacuum evaporation apparatus, and then a surface on which an inorganic evaporation layer was provided. Then, a polyethylene film having a thickness of 40 μm was dry-laminated using an adhesive (“AD817” manufactured by Toyo Morton Co., Ltd.) to obtain a laminate (oxygen gas permeation control layer). When the oxygen gas barrier property of the obtained laminate was measured, it was found to be 1.0 ml / m ² · 24 hr · atm · 25 ° C. · 100% R
H. After heating the white polyethylene terephthalate film on which the discoloration layer was laminated to 80 ° C., it was sandwiched between two laminates so that the polyethylene film surface was in contact with the discoloration layer, and was thermally laminated at 140 ° C. to obtain a time indicator.

Comparative Example 1 White polyethylene terephthalate film “Melinex 329” having a thickness of 100 μm
A color changing layer was laminated on one surface of the sample in the same manner as in Example 1 to obtain a time indicator. Comparative Example 2 A time indicator was obtained in the same manner as in Example 1 except that the thickness of the deposited layer of the mixture of silicon, silicon dioxide and magnesium oxide was changed to about 300 nm. The oxygen gas barrier property of the laminate (oxygen gas permeation control layer) was measured to be 0.01 ml / m ² · 24 hr · at
m · 25 ° C · 100% RH.

Comparative Example 3 A laminate (oxygen gas permeation control layer) containing a vapor-deposited layer of a mixture of silicon, silicon dioxide and magnesium oxide was coated on a 30 μm-thick polyethylene film (oxygen gas barrier property: 5000 ml / m ^2. 24hr ・ atm ・ 2
A time indicator was obtained in the same manner as in Example 1 except that thermal lamination was performed at 120 ° C. instead of 5 ° C. and 100% RH.

The time indicators obtained in Examples 1 to 4 and Comparative Examples 1 to 3 were subjected to a time indicator test. Table 1 shows the results.

[0037]

[Table 1] * 1 ^{unit: ml / m 2 · 24hr ·} atm · 25 ℃ · 100% RH

[0038]

According to the present invention, it is possible to provide a time indicator that can accurately indicate time even when there is a change in the surrounding environment such as temperature and humidity.

 ──────────────────────────────────────────────────の Continuing from the front page (72) Inventor Akio Omata 2-3-113 Kyobashi, Chuo-ku, Tokyo Toyo Inki Manufacturing Co., Ltd.

Claims (5)

[Claims] 1. A color-change layer containing a compound which rapidly changes color by reaction with oxygen is laminated on one or both surfaces of a substrate, and an oxygen gas permeability of 0.1 to 3000 ml / m ^{2 is} provided on the color-change layer.
・ 24hr ・ atm ・ 25 ℃ ・ 100% RH Oxygen gas permeation control layer is laminated and time indicator characterized by the above-mentioned. 2. An oxygen gas permeability of 0.1 to 3000 ml / m ² · 24 hr · atm · 25 on the surface of the substrate on which the discoloration layer is not laminated.
2. The time indicator according to claim 1, wherein an oxygen gas permeation control layer at 100.degree. 3. The time indicator according to claim 1, wherein the oxygen gas permeation control layer includes a layer composed of an inorganic substance. 4. The time indicator according to claim 3, wherein the inorganic substance is one or more compounds selected from silicon oxides, aluminum oxides, magnesium oxides and metal fluorides. . 5. The compound which rapidly changes color upon reaction with oxygen is selected from bis (salicylaldehyde) alkylenediiminecobalt (II), bis (orthohydroxyacetophenone) alkylenediiminecobalt (II) and derivatives thereof. The time indicator according to any one of claims 1 to 4, wherein the time indicator is at least one type of cobalt complex.