JP2807559B2 - 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 for packaging articles easily deteriorated by oxygen, such as food, a method of vacuum packaging in a vinylidene chloride resin coated film bag having excellent gas barrier properties, or a similar bag. In addition, a method of simultaneously sealing a food or the like and an oxygen scavenger to eliminate oxygen inside has been performed.

In these packaging methods, even in the case of a bag having excellent gas barrier properties, oxygen permeates into the bag over a long period of time, or oxygen enters the bag due to unexpected breakage of the bag,
There is a problem of deteriorating the packaged articles.

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 pigment in a reduced state and a filler, which is enclosed in a bag, and when oxygen permeates or infiltrates into the bag, the pigment in a reduced state is oxidized. It has the effect of developing color and allowing the naked eye to detect the presence of oxygen in the bag.

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.

As a means of solving the above problems, the present inventors have previously proposed a label type oxygen indicator.
The oxygen indicator of this label type is very easy to use and has no danger of accidental eating.However, the color developed in the gas barrier bag changes color over time, or becomes faint. There was a problem that the stability was poor and the function as an indicator was deteriorated.

Therefore, an object of the present invention is to provide an oxygen indicator which is excellent in color development stability and the like in addition to the advantages of the label type.

(Means for Solving the Problems) The above object is achieved by the present invention described below.

That is, the present invention provides a sealing agent layer, an oxygen indicator layer and an overprint layer on one surface of a sheet-like substrate in the order described, and an adhesive layer and an adhesive layer on the other surface of the sheet-like substrate. An oxygen indicator label, characterized in that release paper is laminated in the order described in the description, and the filler layer and the overprint layer are formed from a neutral to alkaline resin.

(Function) By making the oxygen indicator into a label, it can be easily fixed to the inner surface of the packaging bag or the direction of the non-packaged article, the oxygen detection is sharp, the detection from the outside is easy, and accidental eating etc. Problem does not occur.

Further, by forming an oxygen indicator layer on a filler layer composed of a neutral to alkaline resin, and laminating an overprint layer composed of a neutral to alkaline resin on the surface of the oxygen indicator layer, the gas barrier property is improved. It neutralizes the acid components such as carbon dioxide in the bag and / or the acidity of the paper used as the base material, so that the developed hue is kept clear for a long time.

Further, by laminating the pressure-sensitive adhesive layer and the release paper on the other surface of the sheet-like base material in the order described above, the oxygen indicator label can be easily attached to an arbitrary position.

(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 comprises a sealant layer 2 made of a neutral to alkaline resin on one surface of a sheet-like substrate 1, an oxygen indicator layer 3, and a neutral to alkaline resin. The overprint layer 4 is laminated in the order described above, and the pressure-sensitive adhesive layer 5 and the release paper 6 are further laminated on the other surface of the sheet-shaped substrate.

Examples of the sheet-like base material 1 used in the present invention include various types of paper such as neutral paper, alkaline paper, and acidic paper, synthetic paper, plastic film, metal foil, and composites thereof.
Any sheet-like material conventionally used in the field of printing can be used and is not particularly limited, but the present invention is useful even with acidic paper.

The filler layer 2 formed on the sheet-like substrate 1 is particularly useful when paper is used as the sheet-like substrate, and is formed from a neutral to alkaline, preferably alkaline resin.

The neutral resin used in the present invention includes the same resin as the resin used as a binder of the ink described below, while, as the alkaline resin, the neutral resin described above,
Examples include those to which an alkaline substance as described below is added. 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 alkali metal salts and amine salts 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, poly (aminoalkyl acrylate) and the like.

The formation of the filler layer is performed by adding an appropriate additive as necessary to the solution or dispersion of the neutral to alkaline resin, and adding the additive to, for example, gravure printing, offset printing, letterpress printing, screen printing, or the like. After being applied to the surface of the sheet-like substrate by a printing method or a coating method, the sheet-like substrate is formed by drying. The filler layer preferably has a thickness of about 1 to 10 g / m ² (when dried).

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

The dye used in the indicator ink has an oxidation state
Any known dye may be used as long as it changes color (coloration or decoloration) in a reduced state, but a preferred dye is a dye which is colored in an oxidized state and which is colorless or pale in a reduced state. Examples 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 or an allyl group); for example, CI sulfur blue 7 and the like, and particularly preferred are the thiazine dyes (1).
The dyes as described above can be used in an oxidized state or a reduced state.

The above dye can be used alone as long as it is in a reduced state, but it is preferable to use a reducing agent in combination in order to increase the stability of the label at the time of 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 a glycosidic bond of a monosaccharide molecule 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.

Further, it is preferable that an appropriate alkaline substance coexist in the indicator ink, and 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, water Potassium oxide, sodium carbonate, potassium carbonate, calcium hydroxide, calcium carbonate, sodium bicarbonate, potassium bicarbonate, calcium bicarbonate, magnesium hydroxide, sodium acetate, potassium acetate, potassium sodium tartrate, potassium 2-ethylhexanoate, etc. Hydroxides, carboxylate salts, 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.

Examples of suitable binders for converting the above dyes and the like into inks include, as preferred examples, ethyl cellulose, ethyl hydroxyethyl cellulose, cellulose derivatives such as cellulose acetyl propionate, butyral resin, polyester resin, acrylic resin, polyether resin, One or more of polyamide resin, petroleum resin and the like can be 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 composition for forming the oxygen indicator layer was prepared by adding the above component system to 5 to 4 parts by weight based on 100 parts by weight of the 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. Is desirable.

The ink composition contains 5% by weight of a polyhydric alcohol such as glycerin or ethylene glycol.
The addition in a small amount is effective in accelerating the discoloration or decoloration of the dye when the label comes into contact with oxygen. In addition, nuclide additives such as nonionic surfactants and auxiliaries can be added to the ink composition.

The ink was prepared in a two-part ink type, that is, a dye A and a reducing agent were added to a binder liquid to prepare a liquid A, while an alkaline substance was added to a binder liquid to prepare a liquid B. Can be used immediately before the formation of the oxygen indicator layer to improve the storage stability of the ink.

Further, the above-mentioned ink composition is not reduced in the composition system, 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 dyes can be added in an amount of about 0.05 to 5% by weight based on the whole ink composition.

The indicator ink composition configured as described above, for example, gravure printing, offset printing, letterpress printing, by a printing method or coating method such as screen printing, after applying to at least one surface of the sheet substrate,
By drying, an oxygen indicator layer is formed. The oxygen indicator layer preferably has a thickness of about 1 to ²⁰ g / m ² (when dried). It is preferable to perform a plurality of times of coating or printing in the case of increasing the thickness of the indicator layer, for example, by repeating the coating or printing more than once in the case of exceeding 5 g / m ^2, per the ink well and A layer in which discoloration is clearly visible can be obtained.

Further, in the present invention, the overprint layer 4 is formed from the same neutral to alkaline resin as described above on the surface of the oxygen indicator layer for the purpose of preventing the ink layer from falling off, improving the surface properties, and improving the coloring stability.

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 formation of the overprint layer is performed in the same manner as the formation of the indicator layer, by applying a solution or dispersion liquid of an appropriate resin, for example, by a printing method or a coating method such as gravure printing, offset printing, letterpress printing, screen printing, or the like. Is formed by applying it to the surface and drying it. The overprint layer is 1 to 10 g / m ² (when dried)
It is preferable to set the degree.

In the present invention, a pressure-sensitive adhesive layer 5 is provided on the back surface of the label obtained above with a conventionally known pressure-sensitive adhesive, and a release paper 6 is further provided on the surface.

By doing so, the label can be easily attached to the inner surface of the gas barrier bag or the surface of the article to be packaged when the label is used.

The pressure-sensitive adhesive to be used is a rubber-based, acrylic-based, silicone-based pressure-sensitive adhesive, and any of conventionally known pressure-sensitive adhesives such as a solution type, an aqueous emulsion type, and a hot melt type can be used. the coating amount is generally a ratio of 1g / m ² ~20g / m ² in solids. The area to be applied may be a part of the back surface of the sheet-shaped substrate as shown in the figure, or may be the entire surface.

The release paper laminated on the surface of the pressure-sensitive adhesive layer has a release layer made of a silicone resin or the like on the surface of paper or plastic film, and any commercially available release paper can be used.

(Examples) Next, the present invention will be described more specifically with reference to reference examples, 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 composition 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 composition Magnesium hydroxide 40 parts Cellulose acetate propionate 25 parts Toluene 17.5 parts Isopropyl Alcohol 17.5 parts Sealant C Cyclic rubber resin 20 parts Magnesium hydroxide 60 parts Toluene 60 parts Cyclohexane 60 parts Overprinting agent D Cyclic rubber resin 20 parts Sodium carbonate 3 parts Toluene 40 parts Cyclohexane 40 parts Reference example 1 Sanyo Using a gravure printing machine on a sterilized paper (DPS, 60g / m ² ) manufactured by Kokusaku Pulp Co., Ltd., using a gravure printing machine, a mixture ink of indicator ink C, ink A and ink B (indicator ink, mixed immediately before printing) and Overprinting agent D is fixed in this order. It was applied and dried at a ratio of ² g / m ² , 5.0 g / m ² and 1 g / m ² in terms of shape. The indicator layer was printed twice.

Reference Example 2 The following filler E was used instead of filler C in Reference Example 1.
Was used, and the other conditions were the same as in Reference Example 1.

Sealant E 20 parts of an acrylic resin containing 2 mol% of sodium acrylate 40 parts of calcium carbonate 40 parts of toluene 40 parts of cyclohexane Reference Example 3 Instead of the sealant C in Reference Example 1, the following sealant F
Was used in the same manner as in Reference Example 1 except that the following overprinting agent G was used in place of the overprinting agent D.

Sealing agent F Acrylic resin containing 5 mol% of N, N-dimethylaminoethyl methacrylate 20 parts Barium sulfate 40 parts Toluene 40 parts Cyclohexane 40 parts Overprinting agent G Acrylic resin containing 5 mol% of vinylpyridine 20 parts Toluene 40 parts Cyclohexane 40 parts Example 1 An adhesive (Olivine BPS3233) manufactured by Toyo Ink Mfg. Co., Ltd. was used on the back surface of the printed matter before cutting obtained in Reference Examples 1 to 3 at a solid content of 2 g / m ^{2 to} 3 g / using a roll coater. The whole surface was coated at a rate of m ² , and release paper was attached to obtain an adhesive sheet. This sheet was half-cut to obtain a label-shaped adhesive seal of the present invention.

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

Example 2 A pressure-sensitive adhesive (Oribine BPS8170) manufactured by Toyo Ink Mfg. Co., Ltd. was used instead of the pressure-sensitive adhesive in Reference Example 1, and the other conditions were the same as in Example 1. The same results as in Example 1 were obtained. Obtained.

Comparative Example 1 The following filler H was used instead of filler C in Reference Example 1.
Was prepared in the same manner as in Example 1 except that the following overprinting agent I was used in place of the overprinting agent D, and an oxygen indicator label of a comparative example was obtained.

Sealant H Acidic acrylic resin 20 parts Toluene 40 parts Cyclohexane 40 parts Overprinting agent I Acidic polyester resin 20 parts Toluene 40 parts Cyclohexane 40 parts The same label as in Example 1 was coated with vinylidene chloride containing Ageless Z-200. When attached to the inside of the bag and sealed, the color changed from blue-violet to vivid red. However, when left as it was for one week, the red color of the oxygen indicator layer became remarkably faint as compared with Examples 1 and 2, and it felt dirty.

(Effects) According to the present invention as described above, by making the oxygen indicator into a label shape, it can be easily fixed to the inner surface of the packaging bag or the surface of the non-packaged article, the oxygen detection is sharp, and the external detection Is easy, and problems such as accidental eating do not occur.

Further, by forming an oxygen indicator layer on a filler layer composed of a neutral to alkaline resin, and laminating an overprint layer composed of a neutral to alkaline resin on the surface of the oxygen indicator layer, the gas barrier property is improved. It neutralizes the acid components such as carbon dioxide in the bag and / or the acidity of the paper used as the base material, so that the developed hue is kept clear for a long time.

Further, by laminating the pressure-sensitive adhesive layer and the release paper on the other surface of the sheet-like base material in the order described above, the oxygen indicator label can be easily attached to an arbitrary position.

[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] An adhesive agent layer, an oxygen indicator layer, and an overprint layer are laminated on one surface of a sheet-like substrate in the order described above, and an adhesive layer and a release layer are formed on the other surface of the sheet-like substrate. An oxygen indicator label, wherein a pattern paper is laminated in the order described above, and the filler layer and the overprint layer are formed from a neutral to alkaline resin. 2. The oxygen indicator label according to claim 1, wherein the filler layer and the overprint layer are formed from an alkaline resin. 3. The oxygen indicator label according to claim 1, wherein the sheet-like substrate is an acidic paper.