JP4765653B2 - Ink composition for oxygen indicator, oxygen indicator using the same, and packaging material containing oxygen indicator - Google Patents

Description

  The present invention relates to an oxygen indicator ink composition for determining a deoxygenated state by an oxygen absorbent, an oxygen indicator using the same, and a packaging material containing the oxygen indicator.

  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. In order to detect this, an 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. In particular, there are many that use methylene blue, and the oxygen indicator using methylene blue exhibits a reduced type, that is, colorless by the action of a reducing agent under deoxygenation, and is oxidized by oxygen in the atmosphere and exhibits blue.

  In addition to tablets, the oxygen indicator has been developed in liquid, ink, sheet, and paper types, as well as those integrated with oxygen absorbers and those integrated with packaging materials. This makes it possible to save labor and to facilitate detection discrimination (see, for example, Patent Document 1). Any reducing agent used in such an oxygen indicator can be used as long as it can maintain the dye in a reduced state, but a strong reducing agent such as a metal hydride changes the dye even in the atmosphere, or This is not preferable because of problems such as poor color development. In consideration of such a viewpoint and safety and health, most of the reducing agents used in oxygen indicators currently on the market use reducing sugars.

  Alkaline substances are required for reducing saccharides to exert their functions, and sodium hydroxide, potassium hydroxide, calcium hydroxide, magnesium hydroxide, calcium carbonate, sodium bicarbonate, calcium bicarbonate, etc. must coexist. . In addition to this, ascorbic acid and the like can also be used. However, in any case, since it exhibits a reducing action at room temperature, it reacts with oxygen in the air to cause a reduction in capacity. In other words, when storing at room temperature, an oxygen absorber must be added, and the oxygen barrier film must be sealed with oxygen barrier film and deoxygenated and packaged, and storage conditions are greatly limited. In addition, it is known that when stored in a deoxygenated state, reducing sugars and ascorbic acid are deteriorated when their elapsed time is long, and the reducing ability cannot be maintained.

  On the other hand, in a packaging material provided with an oxygen indicator function, the filled contents are mostly subjected to a sterilization process, and are often subjected to high-temperature sterilization treatment such as boil and retort.

Prior art documents are shown below.
JP 2001-192592 A

As described above, reducing agents contained in oxygen indicators currently on the market are mostly selected from reducing sugars and reducing vitamins from the viewpoint of safety and hygiene and reducing power. After the process, there is a drawback that the function is lost due to the heat, and it is difficult to guarantee the deoxygenated state after the sterilization process. In this case, since the reducing agent is deactivated after the sterilization treatment, the oxygen indicator shows an oxidation color even though the package is in a deoxygenated state, and there arises a problem that the oxygen indicator does not function normally. Further, it is known that reducing sugars and reducing vitamins are oxidized when left in the atmosphere at room temperature, and their reducing ability is gradually lost over time. Therefore, it is necessary to always keep the oxygen indicator in a deoxygenated state even when stored at room temperature.

  The present invention is intended to solve such problems of the prior art, and does not lose the oxygen indicator function even after sterilization, and can be stored at room temperature in an open atmosphere. It is an object of the present invention to provide an oxygen indicator ink composition that does not need to be treated, an oxygen indicator using the same, and a packaging material containing the oxygen indicator.

The present invention has been made to solve the above problems, and the invention according to claim 1 of the present invention promotes the reduction reaction by changing the color tone from an oxidation color to a reduction color during high-temperature sterilization treatment . An ink composition for an oxygen indicator, wherein a metal catalyst is added .

The invention according to claim 2 of the present invention is the oxygen indicator ink composition according to claim 1, wherein the reducing agent contained in the oxygen indicator ink composition is stable at room temperature and subjected to high-temperature sterilization treatment. an oxygen indicator ink composition, which is a former agent instead that it is possible to reduce the redox dye.

The invention according to claim 3 of the present invention, in claim 1 or 2 oxygen indicator ink composition described before Kikae source agent is an amine, reducing sugars, or higher alcohols or polyhydric alcohols It is an ink composition for oxygen indicators characterized by the above-mentioned.

  Delete.

The invention according to claim 4 of the present invention is the ink composition for an oxygen indicator according to any one of claims 1 to 3 , wherein the metal catalyst is a thermally stable transition metal complex. The oxygen indicator ink composition.

The invention according to claim 5 of the present invention is the ink composition for an oxygen indicator according to any one of claims 1 to 4 , wherein the concentration of the metal catalyst is 20 parts by weight with respect to 1 part by weight of the redox dye. An ink composition for an oxygen indicator characterized by the following.

The invention according to claim 6 of the present invention is an oxygen indicator obtained by applying or printing the ink composition according to any one of claims 1 to 5 on a support.

The invention according to claim 7 of the present invention is the packaging material containing the oxygen indicator according to claim 6 , wherein the support is an exterior body forming a package.

In the ink composition for an oxygen indicator of the present invention, the reducing agent acts during the high temperature sterilization treatment, and changes from an oxidation color to a reduction color. Furthermore, unlike the reducing sugar and ascorbic acid in which an alkaline substance coexists, the reducing agent of the present invention can exist stably for a long time even when stored in the atmosphere at room temperature. Therefore, the oxygen indicator ink composition of the present invention and the sterilization packaging material using the same do not require deoxygenation packaging and are easy to handle. Further, when high-temperature sterilization treatment such as boiling and retort is performed, protons can be quickly released to change the redox dye to a reduced color.

In addition, the oxygen indicator ink composition of the present invention can promote the reduction reaction by adding a thermally stable metal catalyst to the ink composition. Accordingly, it is possible to cope with a case where the processing time required for sterilization is short or a case where the processing temperature is low, and it is possible to prevent the deterioration of the pigment due to heat.

According to the invention of claim 6 and claim 7, the packaging material containing the support coated or printed with the composition for oxygen indicator ink of the present invention exhibits its ability for the first time during the high temperature sterilization treatment, and the packaging. It is possible to easily detect oxygen inside the body.

  An embodiment of the present invention will be described in detail with reference to FIGS.

  Fig.1 (a) is a top view which shows one Example of the package produced with the packaging material (B) containing the oxygen indicator (3) based on this invention, FIG.1 (b) is FIG.1 (a). FIG. 2 is an enlarged side cross-sectional view showing the layer structure of the packaging material (B) of the portion (A) where the oxygen indicator (3) is disposed, and FIG. 2 is a packaging material (B) containing the oxygen indicator (3) according to the present invention. ) Is a graph showing the L value change during the boil treatment, and FIG. 3 is a graph showing the L value change during the retort treatment of the packaging material (B) containing the oxygen indicator (3) according to the present invention. 4 is a graph showing a change in L value during retort treatment after storage for 3 months of a package made of the packaging material (B) containing the oxygen indicator (3) according to the present invention.

  The ink composition for an oxygen indicator according to the present invention comprises at least a redox dye, a reducing agent that is stable at room temperature, a binder resin, and a solvent. And it is the ink composition which added metal catalysts, such as a metal oxide and a transition metal complex, to the said ink composition for the purpose of further promoting a reduction reaction.

  The redox dye used in the present invention is not particularly limited as long as it is a dye that exhibits different colors in an oxidized state and a reduced state, and any known dye can be used. Specifically, in addition to methylene blue, new methylene blue, neutral red, indigo carmine, indigo sulfonic acid potassium salt, safranin T, phenosafranine, capri blue, nile blue, diphenylamine, diphenylamine sulfonic acid, xylene cyanol, nitrodiphenylamine, ferroin, Nitroferroin, N-phenylanthranilic acid and the like can be used.

  As the reducing agent used in the present invention, any reducing agent that exhibits a reducing action when subjected to heat treatment can be used. However, a strong reducing agent such as metal hydride is preferable because it changes the dye. Absent. In addition, reducing sugars that coexist with alkaline substances that exhibit a reducing action at room temperature and ascorbic acid may react with oxygen in the atmosphere and cause a decrease in the capacity of the oxygen indicator, so select a combination of redox dye and reducing agent. It is very important to do. From such a viewpoint, it is preferable to use a mild reducing agent that does not reduce the dye at room temperature, exists stably, and does not react with oxygen in the atmosphere.

Specifically preferred as such mild reducing agents are n-dibutylamine, n-tributylamine, diisobutylamine, diamylamine, triamylamine, n-heptylamine, 2-ethylhexylamine, dioctylamine, diethylenetriamine, tetraethylene. Alkylamines such as pentamine and cyclohexylamine, monoethanolamine,
Alcohol amines such as diethanolamine and triethanolamine, reducing sugars such as maltose, galactose, glucose, fructose and lactose (no alkaline substances coexist), or polyhydric alcohols such as higher alcohols, ethylene glycol, glycerol, propylene glycol and polyvinyl alcohol It is a substance that is generally easily oxidized at high temperatures such as alcohols. Considering safety and hygiene and thermal stability in particular, it is preferable to use triethanolamine or glycerol having a high boiling point, and the amount used is preferably 1 to 100 parts by weight with respect to 1 part by weight of the dye. .

  The binder resin is used for fixing a redox dye, a reducing agent, a metal catalyst, and a solvent on a support. Specific examples of binder resins suitable for ink production include cellulose derivatives such as ethyl cellulose, hydroxyl ethyl cellulose, and cellulose acetate, butyral resins, acetal resins, polyester resins having a hydrophilic group introduced therein, acrylic resins, and urethane-ureas. Examples thereof include resins and urethane resins. In particular, in consideration of the solubility of the redox dye and high temperature sterilization treatment such as boiling and retort, it is preferable to use an aqueous resin having heat resistance.

  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.

  The reduction reaction can be promoted by adding a thermally stable transition metal complex to the ink composition as a metal catalyst. Specifically, as homogeneous catalysts represented by Wilkinson complex, phosphine complexes such as rhodium, ruthenium, cobalt, chromium, molybdenum, tungsten, palladium, platinum, amine complexes, carbonyl complexes, etc., and also cerium, manganese, cobalt , Fatty acid salt complexes such as stearates such as nickel, naphthenates, octylates, oleates and octenoates can be used. It is also possible to use a heterogeneous catalyst in which the transition metal complex is supported on an inorganic compound such as zeolite.

  The metal catalyst is preferably 20 parts by weight or less with respect to 1 part by weight of the redox dye. If the concentration of the metal catalyst is higher than this, it is not preferable because dispersion of the metal catalyst is difficult and a phenomenon that the adhesion strength with the support is lowered occurs.

  In addition to the dispersant, the antifoaming agent, and the oxidation-reduction dye, a coloring agent or the like may be added to the oxygen indicator ink composition of the present invention as needed. 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 and an overcoat layer can be provided above and below the ink composition for the purpose of improving the adhesion strength with the support and preventing the color fading 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 be used.

  The above ink composition is applied to a support to produce an oxygen indicator. Printing and coating methods are used for application. As a 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.

  The support is preferably one that does not react with the ink composition and does not inhibit the coloration of the reagent. Specifically, paper, synthetic paper, non-woven fabric, or synthetic resin film is used. The support is a packaging material containing an oxygen indicator as an exterior body forming a packaging body.

  Further, the packaging material containing the oxygen indicator needs to be provided with an oxygen barrier layer outside the oxygen indicator ink composition for the purpose of preventing oxygen from entering. These materials include polyester resins such as polyethylene terephthalate and polyethylene naphthalate, polyamide resins such as polyamide 6 and polyamide 6-polyamide 66, polyamide resins represented by aromatic polyamides such as MXD6, polyacrylonitrile resins, and polyvinyl alcohol resins. , Thermoplastic resin layer selected from ethylene-vinyl alcohol copolymer resin, polyvinylidene chloride resin, metal foil layer such as aluminum foil, PVD deposition method such as aluminum, silica and alumina, or organo such as hexamethylenedisiloxane Examples thereof include a vapor deposition thermoplastic resin layer obtained by a CVD vapor deposition method using silane, acetylene gas, or other carbon gas sources. Furthermore, a sealant film having heat sealability necessary for forming a package is provided on the inner side. For example, a thermoplastic resin film such as a low density polyethylene resin, a linear low density polyethylene resin, or a polypropylene resin is used.

  Hereinafter, the present invention will be described in more detail with reference to specific examples, but the present invention is not limited thereto.

< Reference Example 1>
(Oxygen indicator layer ink composition)
Methylene blue ... 1.75 parts by weight Triethanolamine ... 10.53 parts by weight Aqueous acrylic resin ... ... 24.56 parts by weight Methanol ... 42.11 parts by weight Water ... 21 .05 parts by weight (form)
An ink composition was obtained by finely dispersing the composition having the above composition with a paint conditioner or the like. As shown in FIG. 1 (b), this was printed twice on a corona-treated surface of a 12 μm thick polyester film (PET) (1) as a support with a gravure plate of 200 lines and 30 μm. The oxygen indicator layer (2) was provided by drying for hours. A urethane-based two-component curable adhesive is used as an adhesive layer (6, 7) for the printed matter, and an alumina vapor-deposited film (4) and a sealant film (5) are respectively laminated on the PET upper and lower sides by a dry laminating method. A packaging material (B) containing the oxygen indicator (3) of the invention was obtained.

< Reference Example 2>
(Oxygen indicator layer ink composition)
Methylene blue ... 1.75 parts by weight Glycerol ... 10.53 parts by weight Aqueous acrylic resin ... 24.56 parts by weight Methanol ... 42.11 parts by weight Water ... -21.05 weight part The packaging material (B) was obtained like Example 1 except the ink composition of the said composition.

<Example 1 >
(Oxygen indicator layer ink composition)
Methylene blue ... 1.67 parts by weight Triethanolamine ... 10.00 parts by weight Cobalt stearate ...・ ・ 5.00 parts by weight Aqueous acrylic resin ・ ・ ・ ・ ・ ・ 23.33 parts by weight Methanol ・ ・ ・ ・ ・ ・ 40.00 parts by weight Water ・20.00 parts by weight A packaging material (B) was obtained in the same manner as in Example 1 except for the ink composition having the above composition.

<Example 2 >
(Oxygen indicator layer ink composition)
Methylene blue ... 1.67 parts by weight Glycerol ... 10.00 parts by weight Cobalt stearate ... .... 5.00 parts by weight Aqueous acrylic resin ... 23.33 parts by weight Methanol ... 40.00 parts by weight Water ... 20.00 parts by weight A packaging material (B) was obtained in the same manner as in Example 1 except for the ink composition having the above composition.

  Below, the comparative example of this invention is demonstrated.

<Comparative Example 1>
(Oxygen indicator layer ink composition)
Methylene blue: 1.49 parts by weight Glucose: 8.96 parts by weight Sodium hydroxide ... .... 14.93 parts by weight Aqueous acrylic resin ... 20.90 parts by weight Methanol ... 35. 82 parts by weight Water ················ 17.90 parts by weight A packaging material (B) is obtained in the same manner as in Example 1 except for the ink composition having the above composition. It was.

<Comparative example 2>
(Oxygen indicator layer ink composition)
Methylene blue ... 1.75 parts by weight Ascorbic acid ... 10.53 parts by weight Aqueous acrylic resin ... 24.56 parts by weight Methanol ... 42.11 parts by weight Water ... -21.05 weight part The packaging material (B) was obtained like Example 1 except the ink composition of the said composition.

<Experiment 1>
The packaging materials (B) obtained in Examples 1 and 2, Reference Examples 1 and 2 and Comparative Examples 1 and 2 were boiled (60 ° C.-30 min, 80 ° C.-30 min) and retorted (121 ° C.-10 min, 121 The temperature of the oxygen indicator (3) was observed, and the change in the L value in the boil treatment (60 ° C.-30 min) and the retort treatment (121 ° C.-30 min) was measured. The results are shown in Table 1 and FIGS.

Table 1 shows the results of observation of the color tone of the oxygen indicator.

<Experiment 2>
The oxygen indicators 3 obtained in Examples 1 and 2, Reference Examples 1 and 2 and Comparative Examples 1 and 2 are shown in FIG.
As shown in a), the packaging material (B) arranged in the portion (A) was simply packaged and stored at room temperature for 3 months. Thereafter, oxygen absorber (8) was added and the atmosphere was replaced with nitrogen, followed by bag making in the same manner, followed by a retort treatment at 121 ° C. for 30 minutes, and the color tone of oxygen indicator (3) was observed and the change in L value was measured. The results are shown in Table 2 and FIG.

Table 2 shows the results of observation of the color tone of the oxygen indicator.

<Experimental result>
From Table 1 and FIG. 2, even in the case where the temperature of the heat treatment was low, in Example 1 and Example 2 to which the metal catalyst was added, it quickly changed to transparent or white. In other configurations, it was not completely reduced, and the blue color of the dye remained.

  From Table 1 and FIG. 3, when the retort process was performed, the reduction color was shown by all the structures. However, in Comparative Example 2, the reduced color could not be maintained. This was considered to be the result of deterioration of the reducing agent by high temperature sterilization.

From Table 2 and FIG. 4, in Examples 1 and 2 and Reference Examples 1 and 2, the oxygen indicator ink was not deteriorated even when deoxidation packaging was not performed, and the ability immediately after sample preparation was maintained in the retort processing. It was confirmed that On the other hand, in Comparative Examples 1 and 2, the reducing agent was consumed by oxygen in the atmosphere during storage for 3 months, and even when subjected to retort treatment, it was not reduced and did not change from blue to transparent and white. .

Fig.1 (a) is a top view which shows one Example of the package produced with the packaging material containing the oxygen indicator based on this invention, FIG.1 (b) has arrange | positioned the oxygen indicator in Fig.1 (a). It is an expanded sectional side view which shows the layer structure of the packaging material of a part. It is a graph which shows L value change at the time of boil processing of the packaging material containing the oxygen indicator which concerns on this invention. It is a graph which shows L value change at the time of the retort process of the packaging material containing the oxygen indicator which concerns on this invention. It is a graph which shows L value change at the time of the retort process after the storage for 3 months of the package produced with the packaging material containing the oxygen indicator which concerns on this invention.

1 ... Polyester film (support)
2 ... oxygen indicator layer 3 ... oxygen indicator 4 ... alumina vapor deposition film 5 ... sealant film 6 ... adhesive layer 7 ... adhesive layer 8 ... oxygen absorbent A ...・ Part B where oxygen indicator is placed ・ ・ ・ Packaging material

Claims (7)

An ink composition for an oxygen indicator, wherein a metal catalyst that changes the color tone from an oxidized color to a reduced color during high-temperature sterilization treatment and promotes a reduction reaction is added . The reducing agent contained in the oxygen indicator ink composition is stable at room temperature, according to claim 1, wherein the a - reducing agent that can reduce the redox dye when subjected to high temperature sterilization treatment Ink composition for oxygen indicator. Before Kikae source agent, amines, reducing sugars, or higher alcohols or polyhydric claim 1 or 2 oxygen indicator ink composition according to, characterized in that an alcohol. The ink composition for an oxygen indicator according to any one of claims 1 to 3, wherein the metal catalyst is a thermally stable transition metal complex. The metal concentration of the catalyst is, according to claim 1 or any one oxygen indicator ink composition according to 4, characterized in that at most 20 parts by weight per 1 part by weight of a redox dye. An oxygen indicator obtained by applying or printing the ink composition according to any one of claims 1 to 5 on a support. The packaging material containing an oxygen indicator according to claim 6 , wherein the support is an exterior body that forms a packaging body.