JP4853247B2 - Oxygen indicator - Google Patents

Description

  The present invention relates to an oxygen indicator for determining a deoxygenated state by an oxygen absorbent, and relates to an oxygen indicator that prevents ink component migration, particularly migration of a redox dye, and is stable in color tone over a long period of time.

  Oxygen is known to oxidize foods and pharmaceuticals due to its high reactivity and to denature and degrade the active ingredients of products. For this reason, many foods and pharmaceuticals prevent oxidation by coexisting oxygen absorbers in the package. At that time, oxygen entry due to the ability of the oxygen absorber, pinholes in the package, poor sealing, etc. To detect. The oxygen indicator is put into the package at the same time.

  Currently, several types of oxygen indicators are available on the market, with different combinations of redox dyes, reducing agents, binder resins, etc. Many oxygen indicators make use of the property that the redox dye exhibits different colors between the reduced and oxidized types. Paying attention to the redox dye, there are many especially those using methylene blue, and the oxygen indicator using this methylene blue exhibits a reduced type, that is, colorless by the action of the reducing agent under deoxygenation, and is oxidized by oxygen in the atmosphere, Presents a blue color.

  When the methylene blue is used as the redox dye, the printing type oxygen indicator has a problem that the dye itself has a strong dyeing property, passes through the film, moves to the contents side, and contaminates the product. Further, it penetrates not only to the inside but also to the oxygen barrier film side. As a result, when the dye reaches a portion without an oxygen barrier, a color tone abnormality is caused. This tendency is remarkable when a large stress is applied to the package body such as high temperature sterilization.

  So far it has been found that dye elution inside can be avoided by using a low elution sealant: PP / COC / PP. However, the elution of the dye to the oxygen barrier film side is fatal, and the only way to solve this problem is to stack the film in multiple layers, and there was no solution that matched the cost of the package. .

  On the other hand, in order to cope with such a problem, a technique has been taken in which an oxygen indicator is wrapped in a package for preventing migration and enclosed in an outer package filled with contents. However, this method has a new problem that a series of operations are complicated and costly, and that it cannot be applied to a printing type oxygen indicator.

  The present invention has been made to solve the above-described problems, and an object thereof is to provide an oxygen indicator with high safety and hygiene that can maintain the color tone of the indicator over a long period of time and a packaging material containing the oxygen indicator.

The present invention solves the above-mentioned problems, and the invention of claim 1 is a method in which an oxygen indicator ink containing a redox dye, which is a thiazine-based dye, is applied onto a substrate, and the redox dye is selectively used. A coating agent containing an adsorbent that is either colloidal aluminum or colloidal silica that adsorbs to the ink is applied to the opposite side of the substrate on which the ink has been applied so as to cover the portion where the ink has been applied. It is a characteristic oxygen indicator.

  In the past, there have been several patents aimed at preventing migration and elution of ink components and adhesive components. However, as far as patents relating to oxygen indicators are concerned, there is no example of applying or laminating a coating agent containing an adsorbent as in the present invention.

  The present invention has been made in view of the drawbacks of the related art, and provides an oxygen indicator that can maintain the color of the reduced color over a long period of time even when the package is used under harsh conditions such as high-temperature sterilization. There is to do.

  In the present invention, by applying or laminating an adsorbent capable of selectively adsorbing the redox dye as a coating agent, a part of the dye can be prevented from reaching the outside of the barrier substrate.

  According to the first aspect of the present invention, a coating agent containing an absorbent that selectively absorbs the redox dye according to the oxygen indicator of the present invention is coated with an ink-coated base so as to cover a portion where the ink is coated. By coating and forming on the opposite side of the material, it is possible to adsorb all the minute amounts of ink components that pass through the film, preventing migration of ink components and solving problems with oxygen indicators such as pigment elution. it can.

Further , when colloidal aluminum or colloidal silica is used as the adsorbent, not only the redox dye can be adsorbed, but also transparency can be secured, and the color development of the indicator is not adversely affected.

Further , thiazine-based dyes containing methylene blue are particularly easily penetrated, and the color tone of the indicator can be maintained over a long period of time by using a coating agent that selectively adsorbs the thiazine-based dye.

  According to the invention of claim 4, it is possible to obtain a package with an oxygen indicator that has stable performance over a long period of time.

  The oxygen indicator of the present invention is coated with a coating agent containing an adsorbent so as to cover the ink on the opposite side of the substrate on which the oxygen indicator ink comprising at least a redox dye, a reducing agent, a binder resin, and a solvent is applied. Alternatively, they are laminated to prevent elution of ink components. As a result, it is possible to prevent the coloring matter from reaching the portion without the oxygen barrier and to solve the color tone abnormality. The best mode for carrying out the present invention will be specifically described below.

As the redox dye used in the present invention, a thiazine dye can be used as long as it is a dye exhibiting a different color tone in an oxidized state and a reduced state. Thiazine dyes with phenothiazine ring especially the elution of a reducing type is remarkable, it is possible to expect a large effect of the present invention. Examples of thiazine dyes include methylene blue, new methylene blue, toluidine blue, thionine acetate, (methylene green) and the like.

  Any reducing agent may be used as long as it has sufficient ability to reduce the dye. Specifically, in addition to ascorbic acid, erythorbic acid and its salts, ascorbate, D-arabinose, D-erythrose, D-galactose, D-xylose, D-glucose, D-mannose, D-fructose, D -Reducing sugars such as lactose, metal salts such as stannous salts and ferrous salts can be used. The effect of the present invention is particularly remarkable when a large stress is applied to the package, such as when high-temperature sterilization is performed. This is presumably because when the package is exposed to a high temperature, it exceeds the glass transition point of PET or ONy, which is a printing substrate, and the dye is extremely easily eluted. In such a case, a substance that decomposes due to heat deactivates the reducing ability and has problems such as failure to maintain color tone, which is not preferable. Preferable as such a reducing agent is specifically rosemary extract, polyphenols such as tocopherol, quercetin and anthocyanin, tea catechin, gallic acid derivatives, amino acids such as caffeic acid, ferulic acid, glutathione, β-carotene and the like Carotenoids such as lycopene. Moreover, some amino alcohols which have hydroxyl groups, such as N-methyldiethanolamine, can also be used conveniently. It is very important to select a combination of a redox dye and a reducing agent, and it is necessary to fully consider the usage environment. Moreover, it is preferable that the usage-amount is 1-100 weight part with respect to 1 weight part of the said pigment | dye.

  The binder resin is used by being dissolved or dispersed in an organic solvent typified by toluene, xylene, methyl ethyl ketone or ethyl acetate, or an aqueous solvent typified by water, methanol, ethanol or isopropyl alcohol. These solvents may be used alone or in combination with a plurality of solvents.

Adsorbents in coating agents that are applied or laminated to prevent migration are those that can selectively adsorb dyes and that do not affect the indicator function , especially so as not to adversely affect the color development of the oxygen indicator. Colloidal aluminum or colloidal silica in which spherical aluminum or spherical silica is dispersed in water is used .

  The particle diameter of silica or alumina used is preferably 5 to 20 nm. If the particle size is smaller than this, it will be difficult to disperse in water, and it will be difficult to coat uniformly due to aggregation. On the other hand, when the particle size is larger than this, the light is diffused, which may hinder the color development of the indicator.

  The thickness of the applied coating agent is preferably about 0.5 μm to 3.0 μm after drying. If the film thickness is thinner than this, the effect of preventing the elution of the dye is not exhibited. On the other hand, when the film thickness is too thick, not only an adverse effect on color development, but also a problem occurs in the adhesion with the substrate.

  The substrate on which the ink is applied is not particularly limited as long as it does not react with the ink composition and does not inhibit the coloration of the reagent, and any of them can be used. Synthetic paper, non-woven fabric, or synthetic resin film is used. In particular, a PET or ONy film having a thickness of about 12 μm is used as a printing substrate, or a film obtained by vapor-depositing a ceramic such as silicon oxide or aluminum oxide as a barrier layer is generally used as an oxygen barrier film.

  In applying the ink or the coating agent of the present invention, a printing method or a coating method is used. As the printing method, a relief printing method, an intaglio printing method, an offset printing method, a screen printing method, and the like can be used. As a coating method, roll coating, spray coating, dip coating, solid coating, and the like are used.

  In the ink composition for oxygen indicator, a surfactant, a dispersant, an antifoaming agent, and a coloring agent may be added separately in addition to the redox dye, if necessary. By adding these into the ink, the stability, quick drying property, and visibility of the ink can be improved. The oxygen indicator ink composition may be adjusted to a two-component type. That is, the storage stability of the ink can be improved by mixing and using at least the liquid A composed of a pigment and a binder resin and the liquid B composed of a reducing agent and a binder resin. Furthermore, an anchor coat layer or an overcoat layer different from the coating agent of the present invention can be provided on the upper and lower sides of the ink composition for the purpose of improving the adhesion strength with the support and preventing further discoloration of the pigment. The coating agent that can be used is not particularly limited as long as it is permeable to oxygen and has good adhesion to the support, or contains an ultraviolet absorbing material and does not interfere with the color development of the oxygen indicator. Can also be used.

  Examples of the present invention will be specifically described below. The present invention is not limited to this.

<Example 1>
This example is an example for comparison.
・ Methylene blue ink composition for oxygen indicator ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ 1.8 parts by weight Rosemary extract ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ 7.2 parts by weight aqueous acrylic Resin ... 5.0 parts by weight Isopropyl alcohol ... 43.0 parts by weight Water ...・ ・ ・ ・ ・ 43.0 parts by weight ・ Packaging oxygen barrier film / ONy ^P / low-elution sealant Low-elution sealant: PP / COC / PP
COC: Cyclic Olefin Copolymer An ink composition was obtained by finely dispersing the above ink composition with a paint conditioner or the like. The ink composition was laminated on a 15 μm corona-treated ONy film with a 200-wire, 30 μm gravure plate and dried at room temperature for 12 hours. A urethane-based two-component curable adhesive was used on the top and bottom of the printed material, and an oxygen barrier film and a low-elution sealant were laminated by a dry laminating method to obtain a packaging material containing the oxygen indicator of the present invention. The thickness of the sealant layer is PP (20 μm) / COC (20 μm) / PP (20 μm), respectively. The oxygen barrier film was an alumina such as GL-ARH / GL-RH, or a silica vapor deposition film. A layer structure becomes the said package. A low-elution sealant was laminated on the surface of the ONy film on which the ink composition was laminated. This packaging material was made into a bag, and after putting an iron-based oxygen absorbent, it was sealed with nitrogen.

<Example 2>
This example is an example of the present application.
・ Oxygen indicator ink composition Same as Example 1 ・ Packaging oxygen barrier film / ^C1 ONy ^P / low-elution sealant
^C1 : Coating agent containing colloidal silica An ink composition was obtained in the same manner as in Example 1. A coating agent containing an adsorbent was applied to a 15-μm ONy film subjected to corona treatment with a 200-wire, 30-μm gravure plate. The coating agent was colloidal aluminum or colloidal silica in which fine spherical aluminum or spherical silica was dispersed in water. The ink composition was laminated on the opposite side of the substrate on which the coating agent was applied, and dried at room temperature for 12 hours. A urethane-based two-component curable adhesive was used on the top and bottom of the printed material, and an oxygen barrier film and a low-elution sealant were laminated by a dry laminating method to obtain a packaging material containing the oxygen indicator of the present invention. The sealant layer and the oxygen barrier film are the same as in Example 1. A layer structure becomes the said package. A low elution sealant was laminated on the surface of the ONy film on which the ink composition was laminated, and a barrier film was laminated on the other surface. This packaging material was made into a bag, and after putting an iron-based oxygen absorbent, it was sealed with nitrogen.

<Example 3>
This example is an example for comparison.
・ Oxygen indicator ink composition Same as Example 1 ・ Packaged oxygen barrier film / ^{C1 / P} ONy / low eluting sealant Except for the layer structure of the package, the oxygen indicator of Example 3 was used in the same manner as in Example 2. The containing packaging material was obtained. A layer structure becomes the said package. A coating agent was applied so as to cover the ink composition on the surface of the ONy film on which the ink composition was laminated, and a barrier film was laminated thereon. This packaging material was made into a bag, and after putting an iron-based oxygen absorbent, it was sealed with nitrogen.

<Example 4>
This example is an example for comparison.
・ Oxygen indicator ink composition Same as Example 1 ・ Packaging oxygen barrier film / ^C2 ONy ^P / low-elution sealant
^C2 : Coating agent containing specially coated activated carbon A packaging material containing the oxygen indicator of Example 4 was obtained in the same manner as in Example 2 except for the layer structure of the package and the coating agent. A layer structure becomes the said package. A low-elution sealant was laminated on the surface of the ONy film on which the ink composition was laminated, a coating agent was applied on the other surface so as to cover the ink composition, and a barrier film was laminated thereon. The coating agent of the present example was a coating agent containing specially coated activated carbon with activated carbon supported on the ceramic surface. As the ceramic, SiO ₂ : MgO: FeO: CaO: A
An inorganic oxide having a composition such as L ₂ O ₃ : NiO: MnO was used. This packaging material was made into a bag, and after putting an iron-based oxygen absorbent, it was sealed with nitrogen.

<Example 5>
This example is an example for comparison.
・ Oxygen indicator ink composition Same as Example 1 ・ Packaged oxygen barrier film / ^C2P ONy / low-eluting sealant The oxygen indicator of Example 5 was the same as Example 3 except for the layer structure of the package and the coating agent. A packaging material containing was obtained. A layer structure becomes the said package. A coating agent was applied so as to cover the ink composition on the surface of the ONy film on which the ink composition was laminated, and a barrier film was laminated thereon. The same coating agent as in Example 4 was used. This packaging material was made into a bag, and after putting an iron-based oxygen absorbent, it was sealed with nitrogen.

[Test 1] Color development observation It was observed whether the oxidized color immediately after printing was not affected by the coating agent and exhibited an original color.

[Test 2] Color tone observation The evaluation samples of Examples 2 to 5 were subjected to high-temperature sterilization treatment (121 ° C-30 minutes) after deoxidation to obtain a reduced color. The reduced color evaluation sample was stored in an environment of 60 ° C.-75% for 1 month, and the change in color tone was observed. The results are shown in Table 1.

［試験３］密着測定
評価サンプルについて、テンシロンによりラミネート強度を測定した。その結果を表２に示す。表では剥離面も示した。

[Test 3] Adhesion measurement For the evaluation sample, the laminate strength was measured with Tensilon. The results are shown in Table 2. The table also shows the peeled surface.

［試験２］の実施例１より、本発明の吸着剤を含むコーティング剤を塗布しない場合、色素が酸素バリアフィルムの外側にまで浸透し、色調異常が発生する。

From Example 1 of [Test 2], when the coating agent containing the adsorbent of the present invention is not applied, the dye penetrates to the outside of the oxygen barrier film, resulting in abnormal color tone.

  From Example 2 of [Test 2], when a coating agent containing the adsorbent of the present invention was applied to the opposite side of the substrate on which ink was applied, all of the trace amount of ink components that permeated and eluted through the substrate were removed. It can be adsorbed, and the color of the indicator can be maintained over a long period of time. Further, since the adsorbent is colloidal silica, transparency can be secured, the color development of the indicator is not adversely affected, and the adhesion to the substrate is good.

  From Example 3 of [Test 2], when the coating agent containing the adsorbent of the present invention was applied on the same side of the substrate on which the ink was applied, that is, the ink composition, the effect of the adsorbent was not recognized, The color became abnormal. This was considered because it was difficult to adsorb all the elution. Further, when the coating agent is in direct contact with the ink, the adhesion strength is not satisfactory.

  From Examples 4 and 5 of [Test 2], when a colored material such as activated carbon is used as the adsorbent, the effect is recognized in preventing the elution of the dye. However, even when the coating amount is small, it adversely affects the color of the indicator, which is not preferable.

Claims (1)

A coating agent containing an adsorbent that is either colloidal aluminum or colloidal silica that selectively adsorbs the redox dye is coated on the substrate with an oxygen indicator ink containing a redox dye that is a thiazine-based dye. An oxygen indicator characterized in that it is applied and formed on the opposite side of the substrate on which the ink has been applied so as to cover the portion on which the ink has been applied and formed.