JP2869953B2 - Oxygen indicator label - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an oxygen indicator label, and more particularly, to an oxygen indicator label which is easy to handle and excellent in oxygen detection.

(Conventional technology and its problems) Conventionally, as a method of packaging articles that are easily degraded by oxygen, such as foods, a method of vacuum packaging in a bag made of vinylidene chloride resin coated film having excellent gas barrier properties, and a similar method. A method of simultaneously sealing a food or the like and an oxygen scavenger in a bag to eliminate oxygen inside the bag has been used.

In these packaging methods, even in the case of a bag having excellent gas barrier properties, oxygen permeates into the inside of the bag for a long period of time, or oxygen invades due to unexpected breakage of the bag, thereby altering the article to be packaged. There is fear.

In such a case, as a method for determining the presence or absence of oxygen inside the bag, an oxygen indicator including a pigment that develops or changes color due to the presence of oxygen is used.

The oxygen indicator is a tablet mainly composed of a reduced dye and a filler, which is enclosed in a bag, and when oxygen permeates or enters the bag, the reduced dye is oxidized to form a color. In addition, it has the effect that the presence of oxygen in the bag can be detected with the naked eye.

However, in the case of the above-mentioned conventional tablet-type indicator, since it is difficult to fix the tablet to the inner surface of the bag or the surface of the non-packaged article, the tablet moves in the bag and becomes invisible from the outside, or the tablet collapses. There are various problems such as generation of powder and erroneous eating by infants.

Accordingly, an object of the present invention is to provide an oxygen indicator that is easy to handle, has excellent oxygen detection properties, and is free from the risk of accidental eating.

(Means for Solving the Problems) The above object is achieved by the present invention described below. That is,
The present invention provides, on the surface of a sheet-like substrate, a sealing layer made of an alkaline resin, a coating amount when dried containing an alkaline substance, and an oxygen indicator layer formed to a thickness of 1 to ²⁰ g / m ² and an alkaline resin. An oxygen indicator label, wherein the overprint layers are laminated in the order described.

(Action) By setting the thickness of the oxygen indicator layer to 1 to 20 g / m ² when dry and forming a label with a specific configuration, it can be easily fixed to the inner surface of a packaging bag or the surface of a non-packaged article, and detect oxygen. Is sensitive and easy to detect from the outside, and there is no problem such as accidental eating.

(Preferred Embodiment) Next, the present invention will be described in more detail with reference to preferred embodiments.

As shown in FIG. 1, the oxygen indicator label of the present invention includes a sealing layer 2 made of an alkaline resin, an alkaline substance, and a dry coating amount of 1
An oxygen indicator layer 3 formed to a thickness of about ²⁰ g / m ^{2 and} an overprint layer 4 made of an alkaline resin are laminated in the order described.

As the sheet-like substrate 1 used in the present invention, any sheet-like material conventionally used in the field of printing, such as various kinds of paper, synthetic paper, plastic film, metal foil, or a composite thereof, can be used. Not limited. In particular, when paper is used as the base material, the sealing layer 2 is formed to eliminate unevenness of the surface of the sheet-like base material 1 and bleeding of the ink in order to improve the oxygen detection property of the oxygen indicator layer. Then, an oxygen indicator layer 3 is formed thereon.

The oxygen indicator layer formed on the filler layer,
Formed from oxygen indicator ink or paint. One example of the oxygen indicator ink or paint contains a pigment that changes color by oxidation and reduction.

The dye used in the indicator ink or paint may be any known dye as long as it changes color (coloration, decoloration) in an oxidized state-reduced state, but a preferred dye is colored in an oxidized state and in a reduced state. The dye is colorless or light-colored, and specific examples of preferable dyes include the following dyes.

(1) As basic structure A thiazine dye having the following formula: for example, methylene blue, etc. (2) As a basic structure Indigo dyes having the following formula: for example, potassium indigo sulfonate, etc. (3) As a basic structure (4) as a basic structure (R represents -H, an alkyl group, an allyl group); for example, CI sulfur blue 7 and the like, and a particularly preferred dye is the thiazine dye of the above (1).
The dyes as described above can be used in an oxidized state or a reduced state.

The above dyes can be used alone in a reduced state, but it is preferable to use a reducing agent in combination in order to increase the stability during label production or stock.

Further, the dye can be used in an oxidized state, and in this case, it is essential to use a reducing agent in combination. That is, in this case, in the label state, the color is developed due to the presence of oxygen in the air, but when this is sealed in a bag together with the oxygen scavenger, the reducing agent used in combination acts to reduce the pigment and discolor. , Is kept in this state. Then, when oxygen enters the bag, the pigment is oxidized again and discolored.

Any reducing agent that can be used in combination with the above dye can be used as long as it can maintain the dye in a reduced state.In the case of a strong reducing agent such as hydrosulfite, the reducing agent can reduce the dye. In some cases, the dye may not be able to develop color due to overreduction, and when the label is stored, the reducing agent itself may be oxidized by oxygen in the air. You have to choose.

From such a point of view, at room temperature, the reducing property of the dye is low,
A reducing agent that is not easily oxidized by oxygen in air at room temperature is preferable.

Preferred as such a weak reducing agent are reducing saccharides. Examples of such reducing saccharides include D-maltose and D-maltose.
-Glucose, D-fructose, D-esthrose,
Monosaccharides such as D-arabinose; reducing oligosaccharides comprising glucosidic bonds in monosaccharide molecules such as maltose and lactose; and fatty acids having a hydroxyl group such as ascorbic acid can also be used. The amount used is preferably 1 to 100 parts by weight per 1 part by weight of the dye.

Also, an appropriate alkaline substance is allowed to coexist in the indicator ink or paint. Such an alkaline substance may be any substance as long as it comes to pH 8 or more upon contact with water, for example, sodium hydroxide, potassium hydroxide, sodium carbonate, potassium carbonate, calcium hydroxide, calcium carbonate, hydrogen carbonate. Hydroxides such as sodium, potassium hydrogen carbonate, calcium hydrogen carbonate, magnesium hydroxide, sodium acetate, potassium acetate, potassium sodium tartrate, potassium 2-ethylhexanoate, carboxylate, various salts and the like. Magnesium hydroxide is particularly preferred from the viewpoint of long-term stability. The amount is preferably 1 to 500 parts by weight per 1 part by weight of the dye.

Suitable binders for converting the dyes or the like into inks or dyes include, for example, preferable examples include ethyl cellulose, ethyl hydroxyethyl cellulose, cellulose derivatives such as cellulose acetyl propionate, butyral resin, polyester resin, acrylic resin, poly One or more of ether resins, polyamide resins, petroleum resins and the like are mentioned.

These binders are preferably aromatic, such as toluene and xylene, ethyl acetate, ester such as butyl acetate, methyl ethyl ketone, ketone such as methyl isobutyl ketone, alcohol such as methanol, ethanol, isopropyl alcohol, and more. It is used by dissolving or dispersing in an organic solvent such as ethylene glycol monoethers or glycols such as ethylene glycol or water. The binder is preferably used by dissolving or dispersing 5 to 100 parts by weight with respect to 100 parts by weight of the solvent.

The ink or paint for forming the oxygen indicator layer is prepared by adding the above-mentioned component system to 5 to 4 parts by weight of the above resin solution.
It is obtained by dissolving or dispersing at a ratio of 0 parts by weight. As a method of dissolving or dispersing, all the components may be mixed and kneaded by a general means such as a sand mill, a ball mill, a roll mill, an attritor, etc. It is desirable to make it into an ink or a paint.

By adding a polyhydric alcohol such as glycerin or ethylene glycol in the above-mentioned ink or paint in an amount of about 5% by weight based on the whole, the discoloration or decoloration of the dye when the label comes into contact with oxygen is added. It is effective in accelerating the color. In addition, various additives and auxiliaries such as nonionic surfactants can be added to the ink or paint.

Further, the above ink or paint is prepared in a two-part type, that is, a dye and a reducing agent are added to a binder liquid to prepare a liquid A, while an alkaline substance is added to the binder liquid to prepare a liquid B. By preparing and mixing these two solutions immediately before the formation of the oxygen indicator layer, the storage stability of the ink or paint can be improved.

Further, the above-mentioned ink or paint is not reduced in the system of the composition, and by separately adding another dye different in color from the dye for the oxygen indicator layer, not only coloring from colorless to colored but also , It can be changed from a color to a color having a different hue. As such a dye, a general pigment or dye which has been widely used as a coloring agent for a conventional printing ink or paint can be used as it is. These other pigments can be added in an amount of about 0.05 to 5% by weight based on the whole ink or paint.

The indicator ink composition configured as described above, for example, gravure printing, offset printing, letterpress printing, a printing method such as screen printing or a coating method, etc., through a sealing layer on at least one surface of the sheet substrate. And then dried to form an oxygen indicator layer. The coating amount of the oxygen indicator layer is 1 to 20 g / m ² (at the time of drying).

Coating amount faint coloring of oxygen indicator layer is less than 1 g / m ^2, it is not easy to detect the color change of the indicator layer due to the presence or absence of oxygen, there are impractical such problems as an indicator the label On the other hand, when the coating amount is more than 20 g / m ₂ , the oxygen indicator layer rises in a convex shape, which is not preferable in appearance. Moreover, it is not preferable in terms of cost. Further, the oxygen indicator layer may be printed twice to obtain an optimum coating amount.

Further, in the present invention, a transparent overprint layer 4 is formed on the oxygen indicator layer for the purpose of preventing the ink or paint layer from falling off. In this case, it is desirable that one of the filler layer and the overprint layer is oxygen-permeable. As a simple method for obtaining oxygen permeability, a method using an appropriate granular additive can be mentioned.

The sealing layer and the overprinter layer are formed from an alkaline resin. Examples of the alkaline resin used herein include those obtained by adding the above-described alkaline substance to the above-described neutral resin. Examples of particularly preferred alkaline substances are hydroxides of alkaline earth metals such as calcium hydroxide, magnesium hydroxide and barium hydroxide. Examples of another alkaline resin include an alkali metal salt and an amine salt of a resin having a carboxyl group in a molecule such as an acrylic acid resin and a maleic acid resin, and a resin having a phenolic hydroxyl group such as a phenol resin. And cationic resins having primary to quaternary nitrogen atoms, such as polyethyleneimine, polyvinylcarbazole, polyvinylpyridine, and poly (aminoalkyl acrylate).

The formation of the filler layer and the overprint layer is performed by adding an appropriate additive to the solution or dispersion of the above-described alkaline resin, if necessary, for example, by gravure printing, offset printing, letterpress printing, screen printing, etc. Is formed on the surface of the sheet-like substrate by a printing method, a coating method, or the like, followed by drying. The coating amount of the filler layer and the overprint layer is preferably about 1 to 10 g / m ² (at the time of drying).

Further, in the present invention, an adhesive layer 5 is provided on any surface of the label obtained above with a conventionally known pressure-sensitive adhesive or heat-sensitive adhesive. When the adhesive layer is formed of a pressure-sensitive adhesive, it is preferable that the release paper 6 be pasted on the surface thereof. When the adhesive layer is made of a heat-sensitive adhesive, release paper is not required. In this way, the label can be easily fixed to the inner surface of the bag or the surface of the article to be packaged when the label is used.

(Examples) Next, the present invention will be described more specifically with reference to examples and comparative examples. In the following description, “part” or “%” is based on weight unless otherwise specified.

 A printing ink having the following composition was prepared.

A ink Methylene blue 0.15 parts Safranin T 0.10 parts Cellulose acetate propionate 30 parts Fructose 15 parts Ethylene glycol 10 parts Toluene 22.5 parts Isopropyl alcohol 22.5 parts B ink Magnesium hydroxide 40 parts Cellulose acetate propionate 25 parts Toluene 17.5 parts Isopropyl alcohol 17.5 Part Sealant C Cyclic rubber-based resin 20 parts Magnesium hydroxide 60 parts Toluene 60 parts Cyclohexane 60 parts Overprinting agent D Cyclic rubber-based resin 20 parts Sodium carbonate 3 parts Toluene 40 parts Cyclohexane 40 parts Example 1 Sanyo Kokusaku pulp On a sterilized paper (DPS, 60g / m ² ) manufactured by Co., Ltd., using a gravure printing machine, a filler C, a mixed ink of A ink and B ink (indicator ink, mixed just before printing) and overprint Agent D was in each case 2 g / m ² of solids in this order, It was applied and dried at a ratio of 5.0 g / m ² and 1 g / m ² . However, the indicator ink is gravure printing 2
It was reprinted.

Using a roll coater, apply an adhesive (Oribine BPS3233) manufactured by Toyo Ink Manufacturing Co., Ltd. on the entire back surface at a solid content of 2 g / m ² using a roll coater. And This sheet was half-cut to obtain a label-like sticker of the present invention.

When the release paper of the above label is peeled off, it is stuck on the inner surface of a vinylidene chloride coated bag containing a deoxidizer (Ageless Z-200) manufactured by Mitsubishi Gas Chemical Co., Ltd. The layer changed from bluish purple to vivid red, and no change was observed in this red color even after one week.

Example 2 The amount of the mixed ink applied in Example 1 was set to 15 g / m ² (solid content), the following filler E was used in place of the filler C, and the other conditions were the same as in Example 1. However, similar results were obtained.

Sealant E Acrylic resin containing 2 mol% of sodium acrylate 20 parts Calcium carbonate 40 parts Toluene 40 parts Cyclohexane 40 parts Example 3 The coating amount of the mixed ink in Example 1 was 3 g / m ² (solid content). The following overprinting agent F was used in place of the overprinting agent D, and the other conditions were the same as in Example 1 to obtain similar results.

Overprinting agent F Acrylic resin containing 5 mol% of N, N-dimethylaminoethyl methacrylate 20 parts Toluene 40 parts Cyclohexane 40 parts Example 4 On the back side of the printed matter obtained in Example 1, a large-scale printing was performed using a gravure printing machine. A heat sealant (Seikadyne 1700W) manufactured by Kogyo Co., Ltd. was applied and dried, and cut into labels. This label was heat-sealed on the inner surface of a vinylidene chloride-coated bag, and a deoxygenator was added to seal the bag. The color changed from blue-violet to red. When the bag was opened and exposed to air, the bag was restored to a blue-violet color.

Comparative Example 1 The coating amount of the indicator ink in Example 1 was set to 0.
A label was prepared in the same manner as in Example 1 except that the amount was changed to 7 g / m ^2, and the same test was performed. As a result, the indicator layer changed color from pale blue-purple to pale pink, but the detection was not easy, and one week Later the pale pink became even lighter.

Comparative Example 2 The coating amount of the indicator ink in Example 1 was 25
A label was prepared in the same manner as in Example 1 except that the amount was changed to g / m ^2, and the same test was performed. As a result, the indicator layer changed color from blue-violet to clear red, and this red color did not change color even after one week. However, the indicator layer is thick and swells,
It was not preferable in appearance as a label.

(Effects) According to the present invention as described above, the thickness of the oxygen indicator layer is set to 1 to 20 g / m ² when dried, and by making it a label having a specific configuration, the inner surface of the packaging bag and the It can be easily fixed to the surface, oxygen detection is sharp, detection from the outside is easy, and problems such as accidental eating do not occur.

[Brief description of the drawings]

FIG. 1 is a diagram schematically illustrating a cross section of the oxygen indicator label of the present invention. 1: Sheet base material 2: Sealant layer 3: Oxygen indicator layer 4: Overprint layer 5: Adhesive layer 6: Release paper

Claims (3)

(57) [Claims] 1. A sealing layer made of an alkaline resin, an oxygen indicator layer containing an alkaline substance and having a coating amount of 1 to 20 g / m ² when dried, and an alkaline resin. An oxygen indicator label, wherein an overprint layer consisting of 2. The oxygen indicator label according to claim 1, wherein a pressure-sensitive adhesive layer or a heat-sensitive adhesive layer is formed on the front surface or the back surface. 3. The oxygen indicator label according to claim 1, wherein the oxygen indicator layer is formed from an ink or paint containing a dye and a reducing agent.