JPH04151555A - Oxygen indicator label - Google Patents

Abstract

PURPOSE:To make it possible to detect oxygen sensitively from the outside by laminating a filler agent layer, an oxygen indicator layer and an over-print layer on one surface of a sheet-shaped substrate, laminating an adhesive agent layer and a mold releasing paper on the other surface, and fixing the label to the inner surface of a packing bag and the surface of a non-packed article. CONSTITUTION:A filler agent layer 2 comprising neutral - alkali resin, an oxygen indicator layer 3 and an over-print layer 4 comprising a neutral - alkali resin are laminated in this sequence on one surface of a sheet shaped substrate 1. An adhesive agent layer 5 and a mold releasing paper 6 are laminated on the other surface. As the sheet-shaped substrate 1, any of various kinds of papers, plastic films, metal foils and the like can be used. The filler agent layer 2 and the over-print layer 4 are formed by adding suitable additive into the solution or the dispersing liquid of neutral - alkali resin as required. The oxygen indicator layer 3 is formed of oxygen indicator ink containing a coloring matter which is discolored by oxidation and reduction. Since the adhesive agent layer 5 is provided, the label can be readily attached to the inner surface and the like of a gas-barrier-type bag when the label is used.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to an oxygen indicator label, and more specifically, provides an oxygen indicator label that is easy to handle and has excellent oxygen detectability.

(Prior art and its problems) Conventionally, packaging methods for products that are easily deteriorated by oxygen, such as foods, include vacuum packaging in bags made of vinylidene chloride resin coated film, which has excellent gas barrier properties, and similar bags. A method of sealing food, etc. and an oxygen absorber at the same time is used to eliminate the enzymes inside.

In these packaging methods, even if the bag has excellent gas barrier properties, oxygen may permeate inside the bag over a long period of time, or if the bag is accidentally damaged, oxygen may enter the bag, causing damage to the packaged goods. There is a problem of deteriorating the quality of

In such cases, an oxygen indicator containing a dye that develops or changes color depending on the presence of oxygen is used as a method for determining the presence or absence of oxygen inside the bag. The oxygen indicator is made up of a tablet containing mainly a pigment in a reduced state and a filler, which is enclosed in a bag, and when oxygen permeates or enters the bag, the pigment in a reduced state is oxidized. The bag develops a color, allowing the presence of oxygen inside the bag to be detected with the naked eye.

However, in the case of the above-mentioned conventional tablet-shaped indicators, it is difficult to fix them to the inner surface of the bag or the surface of non-packaged items, so the tablets may move within the bag and become invisible from the outside, or the tablets may collapse. There are various problems such as powder generation and accidental ingestion by children.

As a means to solve the above-mentioned problems, the present inventor previously proposed a label-type oxygen indicator. This label-type oxygen indicator is very easy to use (and there is no risk of accidental ingestion), but the color developed inside the gas barrier bag may change over time.
There was a problem that the coloring became pale, resulting in poor color development stability and reduced function as an indicator.

Therefore, an object of the present invention is to provide an oxygen indicator that has the advantages of a label type and also has excellent color stability.

(Means for solving problems) The above objects are achieved by the present invention as described below.

That is, in the present invention, a filler layer, an oxygen indicator layer, and an overprint layer are laminated on one surface of a sheet-like base material in the stated order, and an adhesive layer and an overprint layer are laminated on the other surface of the sheet-like base material. This oxygen indicator label is characterized in that release papers are laminated in the order described above, and the sealant layer and overprint layer are formed from a neutral to alkaline resin.

(Function) By making the oxygen indicator in the form of a label, it can be easily fixed to the inner surface of packaging bags or the surface of non-packaged items, and oxygen detection is sensitive and can be easily detected from the outside, as well as preventing accidental ingestion. Such problems do not occur.

In addition, by forming an oxygen indicator layer on a sealant layer made of a neutral to alkaline resin and laminating an overprint layer made of a neutral to alkaline resin on the surface of the oxygen indicator layer, gas barrier properties can be improved. It neutralizes acidic components such as carbon dioxide gas in the bag and/or the acidity of the paper used as the base material, so the developed color remains clear for a long period of time.

Further, by laminating an adhesive layer and a release paper on the other side of the sheet-like base material in the order described above, the oxygen indicator label can be easily attached to any location.

(Preferred Embodiments) Next, the present invention will be described in more detail by citing preferred embodiments.

As shown in the first diagram, the oxygen indicator label of the present invention comprises a sealant layer 2 made of a neutral to alkaline resin, an oxygen indicator layer 3, and a neutral to alkaline resin on one side of a sheet-like base material 1. The overprint layer 4 is laminated in the order described above, and the adhesive layer 5 and release paper 6 are further laminated on the other side of the sheet-like base material.

The sheet-like base material 1 used in the present invention includes various papers such as neutral paper, alkaline paper, and acidic paper, synthetic paper, plastic film, metal foil, or composites thereof, which have been conventionally used in the printing field. Any sheet-like material 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 base material 1 is particularly useful when paper is used as the sheet-like base material, 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 for the ink described below.On the other hand, the alkaline resin includes an alkaline substance such as the one described below in addition to the above neutral resin. Examples include those added.

Examples of particularly preferred alkaline substances include alkaline earth metal hydroxides such as calcium hydroxide, magnesium hydroxide, and barium hydroxide. Examples of other alkaline resins include alkali metal salts and amine salts of resins having carboxyl groups in their molecules such as acrylic acid resins and maleic acid resins, and resins having phenolic hydroxyl groups such as phenolic resins. , polyethyleneimine, polyvinylcarbazole, polyvinylpyridine, poly(aminoalkyl acrylate), and other cationic resins having primary to quaternary nitrogen atoms.

The filler layer is formed by adding appropriate additives as necessary to the solution or dispersion of the above-mentioned neutral to alkaline resin, and printing this by, for example, gravure printing, offset printing, letterpress printing,
By printing methods such as screen printing or coating methods,
It is formed by applying it to the surface of the sheet-like base material and then drying it. The filler layer has a thickness of 1 to 10 glrd (
It is preferable to set the temperature to about 30% when dry.

The oxygen indicator layer formed on the sealant layer is formed from an oxygen indicator ink.

One example of an oxygen indicator ink contains a pigment that changes color upon oxidation and reduction.

The pigment used in the indicator ink may be any known pigment as long as it changes color (coloring, decoloring) in the oxidized state and reduced state, but preferred pigments are colored in the oxidized state and colorless or colorless in the reduced state. It is a dye that gives a light color, and specific examples of preferred dyes include the following dyes.

For example, methylene blue, etc. Indigoid dyes having: For example, indigosulfonic acid potassium salt, etc. Thioindigoid dyes having Mikethrene Brilliant Pink R etc. (R is -H, an alkyl group, an allyl group For example, C1 sulfur blue, etc., and a particularly preferred dye is the thiazine dye shown in (1) above. Dyes such as those mentioned above can be used in either the oxidized state or the reduced state.

The above dyes can be used alone as long as they are in a reduced state, but
It is preferable to use a reducing agent in combination in order to improve the stability during inventory during label manufacture.

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, the label is colored due to the presence of oxygen in the air, but when it is sealed in a bag together with an oxygen absorber, the reducing agent used in conjunction with the label acts to reduce the pigment and change the color. , is kept in this state. If oxygen then enters the bag, the dye will be oxidized again and change color.

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, but in the case of a strong reducing agent such as hydrosulfide, the reducing agent
11 may over-reduce the dye, rendering it incapable of producing color, and the reducing agent itself may be oxidized by oxygen in the air during storage of the label, resulting in insufficient shelf life of the resulting label. Therefore, it is necessary to select a dye.

From this point of view, it is preferable to use a reducing agent that has a low reducing property of the dye at room temperature and is not easily oxidized by oxygen in the air at room temperature.

Preferable such weak reducing agents are reducing saccharides, and examples of such reducing saccharides include D-maltose, D-
Glucose, D-Fructose, D-Ethasulose, D
- Monosaccharides such as arabinose, reducing oligosaccharides consisting of glycosidic bonds of monosaccharide molecules such as maltose and lactose, and fatty acids having hydroxyl groups such as ascorbic acid can also be used. The amount used is 1 of the above pigments.
It is preferably 1 to 100 parts by weight.

Further, it is preferable to coexist an appropriate alkaline substance in the indicator ink, and any alkaline substance may be used as long as it has a pH of 8 or more when it comes into contact with water, such as sodium hydroxide. , potassium hydroxide, sodium carbonate, potassium carbonate, calcium hydroxide, calcium carbonate, sodium hydrogen carbonate, potassium hydrogen carbonate, calcium hydrogen carbonate, magnesium hydroxide, sodium acetate, potassium acetate, potassium sodium tartrate, potassium 2-ethylhexanoate Examples include hydroxides such as salts, carboxylic acid salts, various salts, and the like. Magnesium hydroxide is particularly preferred from the viewpoint of long-term stability. The amount used is preferably 1 to 500 parts by weight per 1 part by weight of the above dye.

Suitable binders for converting the above pigments into ink include:
For example, suitable examples include one or more of ethyl cellulose, ethyl and droxyethyl cellulose, cellulose derivatives such as cellulose acetyl propionate, butyral resin, polyester resin, acrylic resin, polyether resin, polyamide resin, petroleum resin, etc. can be mentioned.

These binders are preferably aromatic binders such as toluene and xylene, ester binders such as ethyl acetate and butyl acetate, ketone binders such as methyl ethyl ketone and methyl isobutyl ketone, alcohol binders such as methanol, ethanol and isopropyl alcohol, and even It is used after being dissolved or dispersed in an organic solvent such as ethylene glycol monoethers or glycols such as ethylene glycol, or in water.

The above binder is added in an amount of 5 to 100 parts by weight per 100 parts by weight of the solvent.
It is preferable to dissolve or disperse parts by weight before use.

The ink composition for forming the oxygen indicator layer is
5 to 4 parts of the above component system is added to 100 parts by weight of the above resin solution.
It can be obtained by dissolving or dispersing it in a proportion of 0 parts by weight. The method for dissolving or dispersing this is to mix all the ingredients and knead them using a general means such as a sand mill, ball mill, roll mill, or attritor. It is desirable to

In addition, by adding polyhydric alcohol such as glycerin or ethylene glycol to the above ink composition in an amount of about 5% by weight based on the total amount, the color change or disappearance of the pigment when the label comes into contact with oxygen is prevented. Effective in speeding up color. In addition, various additives and auxiliary agents such as nonionic surfactants can also be added to the ink composition.

Further, the above ink is prepared in a two-component type, that is, a dye and a reducing agent are added to the binder solution to prepare a solution A, and an alkaline substance is added to the binder solution to prepare a solution B, and both of these solutions are prepared. By mixing and using these immediately before forming the oxygen indicator layer, the storage stability of the ink can be improved.

Furthermore, by separately adding to the above ink composition another pigment that is not reduced within the system of the composition and has a different color from the oxygen indicator shoe dye, it is possible to not only change the color from colorless to colored. , it is possible to change colors from colored to different hues. As such pigments, common pigments and dyes that have been widely used as colorants in conventional printing inks and paints can be used as they are. It can be added in an amount of about 5% by weight.

The indicator ink composition configured as above,
For example, the oxygen indicator layer is formed by applying it to at least one side of the sheet base material by a printing method such as gravure printing, offset printing, letterpress printing, or screen printing, or by a coating method, and then drying it. The oxygen indicator layer preferably has an amount of about 1 to 20 g/g (dry). When increasing the thickness of the indicator layer, it is preferable to apply or print multiple times.For example, if the thickness exceeds 5g/I, repeating the application or printing two or more times will improve ink adhesion and prevent discoloration. The layer can be clearly seen.

Furthermore, in the present invention, an overprint layer 4 made of the same neutral to alkaline resin as described above is formed on the surface of the oxygen indicator layer for the purpose of preventing ink from falling off, improving surface characteristics, and improving color development stability.

In this case, it is desirable that either the sealant layer or the overprint layer be permeable to oxygen. A simple method for making oxygen permeable is to use a suitable granular additive.

The overprint layer is formed in the same way as the indicator layer by applying a suitable resin solution or dispersion to the indicator layer by a printing method such as gravure printing, offset printing, letterpress printing, or screen printing, or by a coating method. It is formed by applying it to the surface and then drying it. The overprint layer has a weight of 1 to 10 g/rr? (during drying).

Further, in the present invention, an adhesive 115 is provided on the back surface of the label obtained above using a conventionally known adhesive, and a release paper 6 is further provided on the surface thereof.

By doing this, you can create a gas barrier when using the label.
Labels can be easily attached to the inner surface of bamboo or to the surface of packaged items.

The adhesive to be used is a rubber-based, acrylic-based, or silicone-based adhesive, and in terms of form, any conventionally known adhesive such as a solution type, aqueous emulsion type, or hot melt type can be used. The coating amount is generally 1g1rd to 20g/rr in terms of solid content. This is the percentage of The area to be coated may be a part of the back surface of the sheet-like base material as shown in the figure, or may be the entire surface.

Further, the release paper laminated on the surface of the adhesive layer is one in which a release layer made of silicone resin or the like is provided on the surface of paper or plastic film, and any commercially available release paper can be used.

(Example) Next, the present invention will be described in more detail with reference to reference examples, examples, and comparative examples. It should be noted that unless otherwise specified, the terms in the text or % are based on weight.

A printing ink having the following composition was prepared.

N cup 2 soil sterilized methylene blue 0.15 parts Safranin T O, 10 parts Cellulose acetate propionate 30 parts Fructose 15 parts Ethylene glycol 10 parts Toluene
22.5 parts isopropyl alcohol
22.5 parts L-free magnesium hydroxide 40 parts Cellulose acetate propionate 25 parts Toluene 17.5 parts Isopropyl alcohol 17.5 parts and cyclized rubber resin 20 parts Magnesium hydroxide 60 parts Toluene
60 parts cyclohexane
60 parts Overprint ID Cyclized rubber resin 20 parts Sodium carbonate 3 parts Toluene
40 parts cyclohexane
40 copies reference example 1 Yamaba Kokusaku Valve ■ sterilized paper (DP, S, 60g/rrr
), using a gravure printing machine, add a mixed ink of filler C1A ink and B ink (indicator ink, mixed just before printing) and an overprint agent in this order, each with a solid content of 2 g/d, 5.0g/rrr and Ig/r
It was applied and dried at a rate of rr. Note that the indicator layer was printed twice.

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

Acrylic resin containing 2 mol% of sodium acrylate in the upper row
20 parts calcium carbonate
40 parts toluene
40 parts cyclohexane 40
Section Reference Example 3 The following procedures were performed in the same manner as in Reference Example 1 except that the following filler F was used instead of filler C in Reference Example 1, and the following overprint agent G was used instead of the overprint agent.

■Acrylic resin containing 5 mol% of N,N-dimethylaminoethyl methacrylate 20 parts barium sulfate
40 parts toluene
40 parts cyclohexane 400
Part Overbund IG Acrylic resin containing 5 mol% vinylpyridine 20 parts Toluene 40 parts Cyclohexane 40 parts Example 1 Toyo Ink Manufacturing Co., Ltd. used a roll coater to coat the back side of the uncut printed matter obtained in Reference Examples 1 to 3. solid content of adhesive (Olivine BP33233) from 2g/rrr to 3g/d
The entire surface was coated at a ratio of 1, and release paper was further attached to form an adhesive sheet. This sheet was cut in half to form a label-like adhesive seal of the present invention.

Peel off the release paper from each of the labels listed above, stick them to the inside of a polyvinylidene chloride-coated bag containing an oxygen scavenger (Ageless Z-200) made by Mitsubishi Gas Chemical, and seal it. The layer changed from bluish-purple to bright red, and no change in the red color was observed for any label even after one week.

Example 2 In place of the adhesive in Reference Example 1, an adhesive manufactured by Toyo Ink Co., Ltd. (Olivine BPS8170) was used, and the other conditions were the same as in Example 1. The same results as in Example 1 were obtained. Ta.

Comparative Example 1 A comparative example was carried out in the same manner as in Example 1, except that the following filler H was used instead of filler C in Reference Example 1, and the following overprint agent I was used instead of the overprint agent. Obtained an oxygen indicator label.

Giant acidic acrylic resin 20 parts toluene
40 parts cyclohexane
40 parts Overprint agent I Acidic polyester resin 20 parts Toluene
40 parts cyclohexane
40 copies When the above label was adhered to the inner surface of a vinylidene chloride coated bag containing Ageless Z-200 and sealed in the same manner as in Example 1, the color changed from blue-purple to bright red. However, when left as is for one week, the red color of the oxygen indicator layer became significantly lighter than in Examples 1 and 2, giving it a dirty appearance.

(Effects) According to the present invention as described above, since the oxygen indicator is in the form of a label, it can be easily fixed to the inner surface of a packaging bag or the surface of a non-packaged article, oxygen detection is sensitive, and the oxygen indicator is in the form of a label. Detection is easy and problems such as accidental ingestion do not occur.

In addition, by forming an oxygen indicator layer on a sealant layer made of a neutral to alkaline resin and laminating an overprint layer made of a neutral to alkaline resin on the surface of the enzyme indicator layer, the gas barrier bamboo Since it neutralizes acidic components such as carbon dioxide gas during manufacture and/or the acidity of the paper used as a base material, the developed color hue is maintained clearly for a long period of time.

Further, by laminating an adhesive layer and a release paper on the other side of the sheet-like base material in the order described above, the oxygen indicator label can be easily attached to any location.

[Brief explanation of drawings]

FIG. 1 is a diagram illustrating a cross section of an oxygen indicator label of the present invention. l: sheet-like base material 2, filler layer 3, dioxygen indicator layer 4, nitrogen print layer 5: adhesive layer 6: release paper

Claims (3)

[Claims] (1) A filler layer, an oxygen indicator layer, and an overprint layer are laminated on one surface of a sheet-like base material in the order described above, and an adhesive layer and a release paper are on the other side of the sheet-like base material. An oxygen indicator label laminated in the order described above, wherein the sealant layer and overprint layer are made of a neutral to alkaline resin. (2) The oxygen indicator label according to claim 1, wherein the sealant layer and the overprint layer are made of an alkaline resin. (3) The oxygen indicator label according to claim 1, wherein the sheet-like base material is acidic paper.