JP2008224391A - Carbon dioxide gas indicator arranged with hydrophobic layer, and package provided therewith - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a carbon dioxide gas indicator having an indication part indicating a satisfactory carbon dioxide gas responsiveness without generating a defective appearance, even when a relative humidity gets high in the peripheral atmosphere of the carbon dioxide gas indicator printed using ink containing a pH indicator. <P>SOLUTION: The carbon dioxide gas indicator is provided with a multilayered indication part containing at least two layers or more of carbon dioxide gas detecting layers, and a hydrophobic layer interposed at least between the carbon dioxide gas detecting layers, and containing a resin having 0-10 wt.% of solubility in water and 1-15 wt.% of water holding rate. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a carbon dioxide gas indicator using an ink composition for detecting that a substituted gas atmosphere in a gas replacement packaging for storing food, beverages, medicines and the like for a long period of time is maintained, and The present invention relates to a package using the same.

  2. Description of the Related Art Conventionally, various types of carbon dioxide indicators that can easily confirm a change in gas atmosphere due to a pinhole in a gas replacement package in which a replacement gas containing carbon dioxide is sealed and occurrence of a seal failure have been put on the market.

  This carbon dioxide indicator contains a pH indicator, and if there is enough carbon dioxide in the surrounding atmosphere, the carbon dioxide gas dissolves in the water in the carbon dioxide indicator and shows weak acidity, resulting in a low pH value. The color tone of the pH indicator changes.

  For example, in the case of a package in which a carbon dioxide indicator and carbon dioxide gas are enclosed together with the contents in the exterior body, if a pinhole or the like is generated in the exterior body and carbon dioxide leaks, the carbon dioxide concentration in the atmosphere around the carbon dioxide indicator is It decreases and the pH value increases, and the color tone of the pH indicator changes accordingly. As described above, when the carbon dioxide indicator is used, the change in the carbon dioxide concentration in the atmosphere around the carbon dioxide indicator can be visually detected using the change in color tone of the pH indicator (see, for example, Patent Document 1). ).

  As such a carbon dioxide gas indicator, there is a carbon dioxide gas indicator ink containing a binder resin and a pH indicator, and a pH indicator portion printed on a support. Such a pH indicator can be printed on various exterior bodies and the like used for the package, so that it is easy to see and convenient. Since the presence of moisture is indispensable for maintaining a clear color tone change in the pH indicator, a binder resin that is dissolved or dispersed in water is used.

  However, carbon dioxide indicators printed using these inks, when the relative humidity of the surrounding atmosphere becomes high, excess water is supplied to the pH indicator, and the carbon dioxide indicator ink is redissolved, and its appearance is There was a problem of being damaged.

  The relative humidity in the exterior body varies depending on the contents, the external temperature and humidity, and the internal space volume. This is especially true for the contents. Foods, beverages, and pharmaceuticals each have a specific water activity represented by the following formula.

Relative humidity (% RH) = water activity × 100
This water activity causes the relative humidity in the exterior body to change greatly. For example, coffee, glue, tea, rice crackers, biscuits, chocolate 0.1 to 0.5, rice, caramel, boiled, medical ampoules 0.5 to 0.7, miso, fresh confectionery, dumplings, bread crumbs, cheese , Chikuwa, Akatsuki, medical solution bag etc. show 0.7-1. The higher the amount of moisture, the higher the relative humidity, causing the appearance of the carbon dioxide indicator to be impaired.

In addition, in the case of contents with a high water content, for example, medical liquid bags, the relative humidity of the space between the medical liquid bag and the exterior body increases only by reducing the thickness of the film of the medical liquid bag, that is, the primary container. However, excessive water was taken into the carbon dioxide indicator, so that the carbon dioxide indicator ink in the indicator was redissolved, and the appearance was impaired.
International Publication No. 01/044385 Pamphlet

  The present invention has been made in view of the above circumstances, and the first object of the present invention is that even when the relative humidity of the atmosphere around the carbon dioxide indicator printed using the ink containing the pH indicator is increased, the appearance is poor. An object of the present invention is to provide a carbon dioxide indicator having an indicator that does not generate and shows a good carbon dioxide responsiveness.

  In addition, the second object of the present invention is to provide a good carbon dioxide responsiveness without causing appearance defects even when the relative humidity of the atmosphere around the carbon dioxide indicator printed using an ink containing a pH indicator is increased. It is providing the package body provided with the carbon dioxide gas indicator which has an instruction | indication part which shows.

The carbon dioxide indicator of the present invention is
A support;
Provided on the support, at least two or more carbon dioxide detection layers formed using a carbon dioxide detection ink composition containing a pH indicator, a binder, and a solvent, and at least interposed between the carbon dioxide detection layers. A carbon dioxide gas detection indicator comprising a multilayer indicator including a hydrophobic layer containing a resin having a solubility in water of 0 to 10 wt% or less and a water retention rate of 1 to 15 wt%,
The total thickness of the carbon dioxide detection layer is 0.8 μm or more, and the thickness of the hydrophobic layer is smaller than the total thickness of the adjacent carbon dioxide detection layers.

The package of the present invention is
A support;
Provided on the support, at least two or more carbon dioxide detection layers formed using a carbon dioxide detection ink composition containing a pH indicator, a binder, and a solvent, and at least interposed between the carbon dioxide detection layers. A carbon dioxide indicator comprising a multilayer indicator including a hydrophobic layer containing a resin having a water solubility of 0 to 10% by weight or less and a water retention rate of 1 to 15% by weight. A package characterized by being placed in an enclosed exterior body,
The total thickness of the carbon dioxide detection layer is 0.8 μm or more, and the thickness of the hydrophobic layer is smaller than the total thickness of the adjacent carbon dioxide detection layers.

  When the present invention is used, the indicator portion of the carbon dioxide indicator printed using an ink containing a pH indicator does not cause poor appearance even when the relative humidity of the surrounding atmosphere increases, and has good carbon dioxide responsiveness. Indicates.

  The indicator for detecting carbon dioxide gas of the present invention includes a support and a multi-layer indicator provided on the support.

  The multilayer indicator includes a multilayer configuration in which at least two carbon dioxide gas detection layers are stacked with a hydrophobic layer interposed therebetween.

  The carbon dioxide detection layer is formed using a carbon dioxide detection ink composition containing a pH indicator, a binder, and a solvent, and the total thickness thereof is 0.8 μm or more, preferably 0.8 μm or more. The thickness is 3 μm.

  When this thickness is less than 0.8 μm, the color of the indicator is thin, and it is difficult to visually recognize a change in color tone. On the other hand, it is preferable that the upper limit of the total thickness of the carbon dioxide gas detection layer is practically about 3 μm. In order to form a carbon dioxide gas detection layer having a thickness greater than this, it is necessary to stack at least four layers of carbon dioxide gas detection ink, which tends to increase costs.

  The hydrophobic layer contains a resin having a water solubility of 0 to 10% by weight and a water retention rate of 1 to 15% by weight, and the thickness thereof is smaller than the total thickness of each carbon dioxide gas detection layer. .

  When the relative humidity of the surrounding atmosphere increases, one of the causes of appearance defects in the indicator part of the carbon dioxide gas detection indicator is caused by the moisture taken into the indicator part being condensed around the core part It is a water drop. When the carbon dioxide gas detection layer has a continuous single layer configuration, the moisture taken into the indicator and absorbed by the carbon dioxide gas detection layer easily moves in the carbon dioxide gas detection layer to generate such water droplets. When the water droplets redissolve the carbon dioxide indicator ink component contained in the indicator, a poor appearance of the indicator occurs.

  Usually, the carbon dioxide gas detection layer can be formed to a thickness that allows a change in color tone of the indicator to be easily recognized. In the multilayer indicator used in the present invention, since the carbon dioxide gas detection layer is divided into two or more layers, the thickness per carbon dioxide gas detection layer can be made thinner than usual. As a result, the amount of moisture absorbed per layer of the carbon dioxide gas detection layer is reduced, and the amount is insufficient to produce water droplets. Further, since each carbon dioxide gas detection layer is divided by the hydrophobic layer, moisture in one carbon dioxide gas detection layer cannot move to the adjacent carbon dioxide gas detection layer. In this way, even if the relative humidity of the ambient atmosphere around the indicator increases, the carbon dioxide detection ink that forms the carbon dioxide detection layer is prevented from redissolving by preventing the generation of water droplets in the carbon dioxide detection layer. can do. Therefore, when the present invention is used, even when the relative humidity of the ambient atmosphere of the indicator increases, the multilayer indicator does not cause an appearance defect and exhibits good carbon dioxide gas responsiveness.

  Any pH indicator can be used as long as it is accompanied by a change in color tone due to the influence of carbon dioxide gas or a color change caused by a change in pH in accordance with a change in the concentration of an alkaline substance.

Table 1 below shows preferred pH indicators and their color ranges.

  A particularly preferred pH indicator is metacresol purple because it is easy to understand changes in safety and color reaction.

  To the ink composition of the present invention, preferably, an alkaline substance greater than 0 and 5% by weight or less can be added. Even if an alkaline substance exceeding 5% by weight is added, the effect is equivalent.

  The alkaline substance used in the present invention can be selected from organic alkalis such as triethanolamine and polyethyleneimine, and alkali hydroxides, alkali carbonates, alkali hydrogen carbonates, ammonia, and the like.

  As the solvent, those capable of uniformly and stably dissolving or dispersing each component of the ink composition of the present invention are selected, and examples thereof include ethers, aromatic hydrocarbons, esters, alcohols, and ketones. It is done. In particular, alcohols are preferable. Further, in order to dissolve a pigment, an alkaline substance or the like to obtain an ink composition and to obtain a good color as an indicator, water is preferably contained. As a ratio of the solvent such as alcohol and water, the solvent is preferably 2 parts by weight with respect to 1 part by weight of water. If the amount of water added is less than 1 part by weight, sufficient color development cannot be obtained and the change in color tone tends to be indistinguishable. Moreover, when water exceeds 1 weight part, there exists a tendency for an external appearance defect to generate | occur | produce on high-humidity conditions.

  The binder resin is used as a binder for fixing components such as a pH indicator on the support, and is not suitable for a resin that swells or dissolves in water after forming a printed layer. A resin that retains water is used. Examples of such a binder include polyacrylic acid, polyvinyl alcohol, polyvinyl butyral, polyvinyl acetal, polyvinyl acetate, polyurethane, and partially saponified vinyl acetate.

  The carbon dioxide gas detecting ink composition of the present invention preferably further contains a polyhydric alcohol. The polyhydric alcohol acts as a humectant, and can hold a solvent such as water in the ink layer serving as the multilayer indicator to facilitate the absorption of carbon dioxide gas and promote the color reaction of the pH indicator.

  As the polyhydric alcohol, glycerin, ethylene glycol, propylene glycol, polyethylene glycol and the like can be used. More preferably, glycerin can be used.

  The addition amount of the polyhydric alcohol is preferably 1% by weight to 10% by weight in the ink composition. If the ratio of the polyhydric alcohol is less than 1% by weight, the color development speed of the multilayer indicator tends to be insufficient. On the other hand, even when the proportion of the polyhydric alcohol exceeds 10% by weight, the color development speed of the multilayer indicator does not change.

  The hydrophobic layer used in the present invention has a solubility in water of 10% by weight or less and a water retention rate of 1 to 15% by weight. When the water retention rate exceeds 15% by weight, poor appearance occurs under high humidity conditions. Further, when the water retention rate is less than 1% by weight, sufficient color development cannot be obtained.

  Moreover, it is preferable that a hydrophobic layer has transparency which can change the color tone of a carbon dioxide gas detection layer visually through this hydrophobic layer.

  Further, the thickness of the hydrophobic layer is preferably 0.5 μm to 5 μm.

  In the present invention, the solubility in water is defined as the weight percent of the resin contained in the aqueous solution when the resin is dissolved in a certain amount of water and becomes insoluble.

  In addition, the water retention rate was measured using a resin support alone and a resin support printed with a multilayer indicator using a carbon dioxide test ink on a resin support in an environment of room temperature 25 ° C. and relative humidity 65%. 1 day after storage, the weight of water contained in each sample was measured with a differential thermothermal gravimetric simultaneous measurement device (TG / GTA), and after taking the difference between the two, the total of the weight of the support and the weight difference of water The difference in water weight with respect to weight.

  Examples of the resin used for the hydrophobic layer include hydrophobicity such as polyvinyl formal, polyvinyl acetal, polyvinyl ketal, partially saponified polyvinyl alcohol, partially saponified ethylene vinyl alcohol copolymer, polyvinyl acetate, polyurethane, and polyester. Resin.

  As the polyvinyl alcohol, those having a high degree of saponification with little decrease in film strength due to moisture absorption are suitable.

  If necessary, a hygroscopic pigment can be added to the hydrophobic resin.

  Examples of the hygroscopic pigment include magnesium sulfate, calcium oxide, calcium chloride, shochu liquor, aluminum oxide, silica gel and the like in addition to ordinary color pigments such as barium sulfate and titanium oxide.

The pH indicators shown in Table 1 can be determined not only by the change in color tone of the indicator itself, but also by the change in color tone due to color mixing with other color pigments.
For such a purpose, a colorant can be added to the carbon dioxide gas detecting ink composition of the present invention.

  When a colorant is added and mixed with the color of the carbon dioxide gas detection ink composition, for example, when the change in the color tone of the indicator itself is difficult to visually determine, or when the design is not a desired color tone, It can be changed to a color tone that is easy to visually determine, or a color tone that is desired in design.

  For the same purpose, a colored support other than white can be applied, and a multilayer indicator using the carbon dioxide gas detecting ink composition of the present invention can be provided thereon.

  Further, for the same purpose, the hydrophobic layer can be colored to such an extent that the transparency is not impaired.

  Examples of colorants include edible red No. 2 (Amaranth), edible red No. 3 (erythrosin), edible red No. 40 (Arla Red AC), edible red No. 102 (New Coxin), edible red No. 104 (Phloxine), edible Red No. 106 (Acid Red) and red colorants such as natural cochineal pigments, edible yellow No. 4 (tartrazine), edible yellow No. 5 (Sunset Yellow FCF), and yellow colorants such as natural red safflower yellow Blue colorants such as Food Blue No. 1 (Brilliant Blue FCF) and Food Blue No. 2 (Indigo Carmine) can be mentioned.

  In addition to adding a colorant to the ink composition, the same change in color tone can be obtained by using a colored support.

  In addition, in order to improve the coatability of other inks, various agents such as surfactants, varnishes, compounds, drying inhibitors, and dryers may be added within a range that does not affect the color development of the carbon dioxide detection ink. Is possible.

As a method for applying the ink to the support, a printing method such as a screen printing method, an intaglio printing method, a gravure printing method, or a coating method such as roll coating, spray coating, or dip coating is preferably used.
The multilayer indicator used in the present invention is preferably a printing method because it is desired that the coating amount of the ink composition is relatively large and constant.

  The multilayer indicator used in the present invention can be printed on an exterior body to produce a package having the indicator of the present invention.

  For example, when processing a packaging bag by continuously printing a multilayer indicator on a support, heat sealing and cutting, gravure printing or flexographic printing is suitable because the support can be wound and supplied. .

  As the support, one that does not react with the ink composition of the present invention and does not inhibit the coloration of the reagent can be selected. As such a support, for example, paper, synthetic paper, non-woven cloth, or synthetic resin film can be used.

  Synthetic resin films include, for example, polyester, polyamide, polyvinyl alcohol, cellophane, ethylene vinyl alcohol copolymer, polyethylene, polypropylene, polymethylpentene, and the like, and transparent deposited films provided with silica or alumina deposited layers on these films. Etc. can be used in accordance with the purpose and usage.

  Moreover, it is preferable that a multilayer instruction | indication part consists of an ink layer which has patterns, such as a character and a pattern.

  In particular, when a character is selected as the multilayer instruction section, it can also be used as a label on which a product name or the like is printed.

  The usage form of the carbon dioxide indicator used in the present invention is as follows: (1) A container made of a gas barrier material for storing contents such as foods, beverages, and medicines is a carbon dioxide atmosphere, and a carbon dioxide indicator is provided in the container. (2) A container made of a gas permeable material containing the contents is packaged with an exterior body made of a gas barrier material, the inside of the exterior body is in a carbon dioxide gas atmosphere, and a carbon dioxide gas indicator is placed in the exterior body The method of doing can be illustrated.

  More specifically, in the case of the above (1), as a method for arranging the carbon dioxide gas indicator, for example, paper, synthetic paper, non-woven paper, synthetic resin film, or a laminate in which at least two kinds of the above materials are combined. A method of simply putting the carbon dioxide indicator printed on the support into the container, a method of adhering the carbon dioxide indicator to the inner surface of the container, or using the material constituting the container as a support, the ink composition described above on the inner surface of the container There is a direct printing method.

  On the other hand, in the case of (2) above, the carbon dioxide indicator can be arranged on the outer surface of the container, the space between the container and the outer body, and the inner surface of the outer body. As a method for disposing carbon dioxide indicators on the outer surface of the container or the inner surface of the outer package, there are a method of adhering the indicator to these surfaces, or a method of printing the ink composition used in the present invention directly on these surfaces. .

  In the case where the ink composition is directly printed on the inner surface of the container made of the gas barrier material in (1), the outer surface of the gas permeable container in (2) or the inner surface of the exterior body made of the gas barrier material, After printing the ink composition on the film, it is also possible to cover the printed surface with a gas permeable film. When coated, there is no contact with the contents or the container, it is hygienic and the wear of the multilayer indicator is also reduced. This is preferable because it can be prevented.

  Examples of foods, beverages, and chemicals to which the carbon dioxide indicator of the present invention can be applied include those that may be altered by contact with oxygen, or those that may lose quality or lose their efficacy due to the release of carbon dioxide. There is.

  Examples of foods and beverages include tea, coffee, cheese, ham, miso, and raw meat.

  Examples of chemicals include bicarbonate-containing drug solutions, amino acid infusions, fat emulsions, antibiotic preparations, and the like. In particular, a bicarbonate-containing chemical solution is a chemical having a property of losing medicinal properties by releasing carbon dioxide. For this reason, it can preserve | save, preventing discharge | release of a carbon dioxide gas by packaging the container which stored the bicarbonate containing chemical | medical solution with a carbon dioxide gas in the exterior body.

Hereinafter, the present invention will be specifically described with reference to the drawings.

  FIG. 1 is a front view showing a first example of the carbon dioxide indicator of the present invention, FIG. 2 is a sectional view thereof, and FIG. 3 is an enlarged view of a part of FIG.

  As shown in FIGS. 1 and 2, the indicator 10 includes a multilayer indicator 2 formed on both sides of a support 1 made of, for example, a polyethylene terephthalate film, and a porous film 3 having carbon dioxide gas permeability around it. It has the structure surrounded by. FIG. 3 is an enlarged view of a portion of the multilayer instruction unit 2 of FIG. As shown in the figure, the multi-layer indicator 2 has a circular pattern formed of, for example, a carbon dioxide gas detection ink composition comprising metacresol purple, sodium carbonate, polyvinyl acetal resin, microcrystalline cellulose, and water, as shown in FIG. On the first carbon dioxide gas detection layer 35 and the first carbon dioxide gas detection layer 35 obtained by screen printing, the solubility in water is 10% by weight or less and the water retention rate is 1 to 15% by weight. A hydrophobic layer 36 obtained by applying a certain polyvinyl acetal resin by screen printing in a circular pattern, and further formed by applying the same carbon dioxide gas detecting ink composition to the hydrophobic layer 36 by screen printing. 2 carbon dioxide gas detection layers 37.

  The multilayer indicator 2 of this indicator is purple in normal air. 1 and 2, the multilayer indicator 2 is provided on both surfaces of the support 1, but a configuration in which the multilayer indicator is provided only on one surface can also be applied. Moreover, although this indicator is surrounded by the air permeable film 3, it can be used as it is without using the air permeable film 3.

  FIG. 4 is a sectional view showing the configuration of a second example of the carbon dioxide indicator of the present invention.

As shown in the figure, this carbon dioxide gas indicator 70 is an example in which a multilayer indicator is provided only on one surface, and as a support, for example, a layer 71 having carbon dioxide gas impermeability made of a film obtained by vapor-depositing silica on a polyester resin. The carbon dioxide-impermeable layer 71 has, for example, metacresol purple, sodium carbonate, polyvinyl acetal resin, microcrystalline cellulose, and water-containing carbon dioxide detection ink composition and water solubility of 10% by weight or less. And a multilayer indicator 2 obtained by applying a hydrophobic layer of polyvinyl acetal resin having a water retention rate of 1 to 15% by weight by screen printing in a circular pattern on the layer 71 having carbon dioxide impermeability. Carbon dioxide made of, for example, a polyethylene film formed so as to seal the provided multilayer indicator 2 Composed of a layer 73 having transparency.

Here, carbon dioxide impermeability means having a carbon dioxide permeability of 50 (ml / m ² · 24 hours) or less at a room temperature of about 23 ° C. and a relative humidity of about 40%.

Carbon dioxide gas permeability means having a carbon dioxide gas permeability of 500 (ml / m ² · 24 hours) or more at a room temperature of about 23 ° C. and a relative humidity of about 40% RH.

  The carbon dioxide indicator 70 has a configuration in which carbon dioxide gas is transmitted and detected only from the layer 73 side having carbon dioxide permeability, and carbon dioxide gas is not transmitted from the support side. For example, a packaging body is used as a support, and a packaging body is prepared so that the carbon dioxide-impermeable layer 71 is on the outside and the carbon dioxide-permeable layer 73 is on the inside. The package can be configured such that the indicator 70 functions within the package. The package thus obtained has excellent responsiveness to changes in the atmosphere and excellent carbon dioxide retention, so that the contents can be stored well.

If the carbon dioxide gas permeability of the layer through which carbon dioxide gas should permeate is lower than 500 (ml / m ² · 24 hours), the response to changes in the carbon dioxide gas atmosphere is delayed, and there is a risk of erroneous determination.

For example, in the case of forming a package, if the carbon dioxide permeability of the layer that should be impermeable to carbon dioxide is higher than 50 (ml / m ² · 24 hours), the carbon dioxide atmosphere in the package can be maintained. Can not.

The resin film having a carbon dioxide gas permeability of 50 (ml / m ² · 24 hours) or less that can be used in the present invention is a base film made of a synthetic resin such as a polyester (PET) film or a nylon (Ny) film. Examples thereof include a transparent vapor-deposited film on which silica or alumina is vapor-deposited, a polyvinylidene chloride (PVDC) film, a polyvinyl alcohol (PVA) film, an ethylene vinyl acetate copolymer (EVOH) film, and the like.

  These films can be used alone or laminated. Moreover, in order to obtain the strength, heat resistance, etc. according to the intended purpose, other resin films can be laminated. For example, a nylon film or the like can be laminated to obtain a piercing strength.

Examples of the film having a carbon dioxide gas permeability of 500 (ml / m ² · 24 hours) or more used in the present invention include polyolefins such as polyethylene film and polypropylene film. Note that low-density polyethylene and unstretched polypropylene have heat-sealing properties and are optimal as a packaging bag inner layer.

A support on which a multilayer indicator is printed, a film having a carbon dioxide permeability of 50 (ml / m ² · 24 hours) or less, and a film having a carbon dioxide permeability of 500 (ml / m ² · 24 hours) or more, In addition, as a method of bonding other films, a known method can be used, for example, dry lamination using an adhesive can be used.

  FIG. 5 is a sectional view showing the configuration of the third example of the carbon dioxide gas indicator of the present invention.

As shown in the figure, this carbon dioxide gas indicator 50 includes, for example, a nylon film 55 having an alumina vapor deposition layer (not shown), and an alumina vapor deposition layer (not shown) laminated thereon via an adhesive layer 56. The multilayer indicator 2 is sealed on the support 1 made of the polyester film 57 having the anchor coat layer 51 formed on the support 1 and the anchor coat layer 51 on which the multilayer indicator 2 is printed. And an overcoat layer 52 formed as described above. The multilayer indicator 2 of this indicator is purple in normal air.

  The pH indicator in the indicator reacts via a solvent such as a hydrophilic solvent such as water or an alcohol compound. For this reason, the indicator may contain such a solvent. For this reason, the indicator is liable to collect water and easily cause poor appearance. Further, the indicating unit is vulnerable to external impact, and is easily peeled off and broken around the indicating unit and its periphery.

  In the third example of the carbon dioxide indicator of the present invention, by sandwiching the multilayer indicator 2 between the anchor coat layer 51 and the overcoat layer 52, the carbon dioxide detection ink composition constituting the multilayer indicator 2 is protected, Appearance defects, peeling, and breakage can be prevented. Furthermore, the long-term stability of the carbon dioxide indicator including water resistance, light resistance, and heat resistance is improved.

  The anchor coat layer 51 is a water-insoluble material having good adhesion between the support 1 and the indicator 2 formed thereon, and the overcoat layer 52 is carbon dioxide permeable. A material having good adhesion to the indicator 2 and optionally, for example, an adhesive layer or other resin layer that can be further provided on the multilayer indicator 2 can be preferably used.

  As such materials, for example, urethane resins and polyvinyl acetal resins can be used alone or in combination.

  Here, the multilayer indicator is provided only on one side of the support 1, but a configuration in which the multilayer indicator 2 is provided on both sides of the support 1 can also be applied. Further, when providing a multilayer indicator on only one side of the support 1, if necessary, the above-mentioned layer having carbon dioxide impermeability as a support, and carbon dioxide gas permeability on the overcoat layer. Each of the layers can be applied.

  Moreover, FIG. 6 is sectional drawing showing the structure of the 4th example of a carbon dioxide gas indicator.

As shown in the figure, this carbon dioxide indicator 60 is an improved example of the carbon dioxide indicator 50 described above, and instead of the anchor coat layer 51, a first anchor coat layer 53 and a second anchor are provided on the support 1. Except that the laminated structure of the coat layer 54 is used, it has the same structure as the carbon dioxide gas indicator shown in FIG. Preferably, the peripheral portion of the first anchor coat layer 53 and the overcoat layer 52 are brought into close contact with each other so that the multilayer indicator 2 and the second anchor coat layer 54 are enclosed in the two layers 52 and 53.

As the first anchor coat layer, a water-insoluble material having good adhesion to the support 1 such as urethane resin is preferably used. Further, the second anchor coat layer has good adhesion to the first anchor coat layer and the multilayer indicator 2, and more preferably has a hydrophilic group and retains water with respect to the multilayer indicator 2 containing water. A material having an effect such as a butyral resin is preferably used.

  As the overcoat layer, for example, urethane resin can be used.

As a method for applying the anchor coat layer and the overcoat layer, a printing method such as a screen printing method, an intaglio printing method, a gravure printing method, or a coating method such as roll coating, spray coating, or dip coating is preferably used. .

  In this carbon dioxide gas indicator 60, the anchor coat layer is divided into two layers, so that the first anchor coat layer 53 functions to strengthen the adhesion between the support 1 and the multilayer indicator 2, The two anchor coat layers 54 provide an action of securing a sufficient amount of moisture so that at least the pH indicator in the multilayer indicator 2 functions. Accordingly, the carbon dioxide gas indicator 60 has a stronger adhesion and more effective water retention for the multi-layer indicator than the formation of only one anchor coat layer, like the carbon dioxide gas indicator 50 shown in FIG. Can be realized. Furthermore, the long-term stability of the carbon dioxide indicator including light resistance and heat resistance is further improved.

  Here, the multilayer indicator is provided only on one side of the support 1, but a configuration in which the multilayer indicator 2 is provided on both sides of the support 1 can also be applied. Further, when providing a multilayer indicator on only one side of the support 1, if necessary, the above-mentioned layer having carbon dioxide impermeability as a support, and carbon dioxide gas permeability on the overcoat layer. Each of the layers can be applied.

  In FIG. 7, the figure showing the 1st example of the gas replacement packaging body concerning this invention is shown. As shown in the figure, this gas replacement package 20 is made of, for example, a polyethylene container 11 containing contents such as chemicals and beverages, and a carbon dioxide gas indicator 10 with 50% nitrogen and 50% carbon dioxide as replacement gases. % Mixed gas 13 is used to enclose the outer package 12 made of a gas barrier laminated film.

  The multilayer indicator 2 of the indicator in the package is yellow when enclosed. However, if pinholes or poor seals occur in the package and the replacement gas leaks out and the surrounding air is mixed in instead, the carbon dioxide concentration in the package decreases. For this reason, the gas atmosphere around the indicator 10 changes, and the color tone of the multilayer indicator 2 changes from yellow to light brown, and further to purple according to pH. By visually recognizing the change in the color tone, it can be easily confirmed whether or not the atmosphere containing carbon dioxide in the package is maintained.

  Instead of the carbon dioxide indicator 10, the third and fourth examples of the carbon dioxide indicator described above can be applied.

  FIG. 8 shows a second example of the gas replacement package according to the present invention.

  As shown in the figure, the package 30 is formed by using the ink composition of the present invention on the surface of a polyethylene film container 14 in which contents such as raw block meat are vacuum-packaged, with the exterior portion of the container 14 as a support. A carbon dioxide gas indicator 18 having a multilayer indicator 2 formed by screen printing and a coating layer 8 made of a breathable material coated on the multilayer indicator 2 is provided, and 50% nitrogen, carbon dioxide as a replacement gas A 50% by volume mixed gas 13 is used to enclose a package 12 made of a gas barrier laminate film. Moreover, it can also be set as the package which has the structure similar to the package 30 of FIG. 8 except not providing the coating layer 8. FIG.

  Even in the package 30, as in the package shown in FIG. 7, it is possible to easily confirm whether or not the gas atmosphere containing the carbon dioxide gas in the package is maintained by visually recognizing the change in the color tone.

  Instead of the carbon dioxide indicator 18, the above-described second example, third example, and fourth example of the carbon dioxide indicator can be applied.

  FIG. 9 shows a third example of the gas replacement package according to the present invention.

  In addition to the package shown in FIG. 7 and FIG. 8, as shown in FIG. 9, the multilayer indicator 2 is printed on the exterior 12, or the indicator 10 formed of the support 1 provided with the multilayer indicator 2 is provided in the exterior 12. It may be used by being integrated with the package by a method such as adhering to the package.

  The packaging body 40 is composed of an exterior body 12 made of a gas barrier laminated film, and a multilayer instruction provided on the inner surface of the exterior body 12 by, for example, screen printing using the ink composition of the present invention with the exterior body 12 as a support. The carbon dioxide gas indicator which has the part 2 is comprised. In this package 40, for example, two laminated films are arranged with the multilayer indicator 2 inside, and the contents 16 are arranged between them, and then replaced with a mixed gas 13 of 50% by volume of nitrogen and 50% by volume of carbon dioxide. However, it can be formed by hermetically sealing the periphery of the exterior body 12 by heat sealing.

  In FIG. 10, the figure showing an example of the structure of the carbon dioxide gas indicator which can be used for the 3rd example of the gas replacement packaging body concerning this invention is shown.

In the case of an indicator in which the multilayer indicator 2 is printed using the ink composition of the present invention with the exterior body 12 as a support, as shown in FIG. 10, the laminate 31 including the gas barrier layer constituting the exterior body 12 It is also possible to provide the multilayer indicator 2 on the inner surface of the gas barrier layer 32 and cover the inner surface of the multilayer indicator 2 with a protective film 33 that is permeable to carbon dioxide gas.

  By adopting a configuration in which the multilayer indicator 2 is not exposed in this way, the multilayer indicator 2 is not directly in contact with the container or the contents, and the multilayer indicator 2 is worn during the manufacturing process or during transportation. Can be prevented.

  Instead of the carbon dioxide indicator, the above-described second example, third example, and fourth example of the carbon dioxide indicator can be applied.

  In FIG. 11, sectional drawing showing the example which applied the 4th example of the carbon dioxide gas indicator which concerns on this invention to the exterior body of a package is shown.

  As shown in the figure, for example, a nylon film 81 having an alumina vapor deposition layer (not shown) and a polyester film 83 having an alumina vapor deposition layer (not shown) are disposed as adhesives serving as a support through an adhesive layer 82. A laminated film obtained by laminating is used. Similarly to the fourth example of the carbon dioxide indicator shown in FIG. 6 on this laminated film, the laminated structure of the first anchor coat layer 53 and the second anchor coat layer 54, the multilayer indicator 2, and the overcoat By providing the coat layer 52 in order, a carbon dioxide indicator is configured. In addition, an ink layer 17 having, for example, a character such as a product name or a pattern such as an image can be provided in other regions on the exterior body in parallel with the production of the carbon dioxide indicator 80. Further, on the overcoat layer 52 and the ink layer 17, for example, a sealant layer 75 made of low density polyethylene is provided via an adhesive layer 74.

A package with a carbon dioxide indicator is obtained by sealing the contents using, for example, 50% by volume of nitrogen and 50% by volume of carbon dioxide as a replacement gas using an exterior body provided with such a carbon dioxide indicator. It is done.

  In the obtained package, it is possible to realize strong adhesion of the multilayer indicator and effective water retention for the multilayer indicator. Furthermore, the long-term stability of the package with a carbon dioxide indicator including water resistance, light resistance and heat resistance is improved.

Examples Hereinafter, the present invention will be specifically described with reference to Examples.

Example 1
Carbon dioxide detection layer composition:
Metacresol purple 1 part by weight, sodium hydroxide 4 parts by weight, binder resin 7 parts by weight, glycerin 5 parts by weight, n-propanol 84 parts by weight, water 28 parts by weight Hydrophobic layer composition:
8 parts by weight of urethane resin having a solubility in water of 3% by weight and a water retention rate of 10% by weight, 5 parts by weight of isopropyl alcohol, 10 parts by weight of ethyl acetate, 5 parts by weight of methyl ethyl ketone, 10 parts by weight of toluene, anchor coat layer, overcoat layer composition:
8 parts by weight of urethane resin, 5 parts by weight of isopropyl alcohol, 10 parts by weight of ethyl acetate, 5 parts by weight of methyl ethyl ketone, 10 parts by weight of toluene
An anchor coat layer 0.5 μm, a first carbon dioxide gas detection layer 1 μm, a hydrophobic layer 1 μm, a second carbon dioxide gas detection layer 1 μm, and an overcoat layer 1 μm are sequentially formed on one side of a 12 μm thick polyester film support by a gravure printing method. A multi-layer indicator was formed by laminating, and a carbon dioxide gas permeable layer made of, for example, a polyethylene film was formed thereon to obtain a carbon dioxide indicator having the same configuration as in FIG.

  The obtained carbon dioxide indicator is put into a transparent outer casing made of a gas barrier substrate, the inside is replaced with carbon dioxide 50% nitrogen 50%, the contents containing the sodium bicarbonate solution are enclosed, and the internal relative humidity is 70. % Of the package was obtained. The resulting package was allowed to stand for 2 weeks under high temperature and high humidity conditions at room temperature of 60 ° C. and a relative humidity of 75%. When the appearance and color development were observed, the appearance and color development were not observed.

  The obtained results are shown in Table 2 below.

Example 2
A package was obtained in the same manner as in Example 1 except that the hydrophobic layer composition was changed as follows.

Hydrophobic layer composition:
6 parts by weight of polyvinyl acetal resin having a water solubility of 6% by weight or less and a water retention rate of 10% by weight, 4 parts by weight of isopropyl alcohol, 8 parts by weight of ethyl acetate, 5 parts by weight of methyl ethyl ketone, 12 parts by weight of toluene
The resulting package was allowed to stand for 2 weeks under high temperature and high humidity conditions at room temperature of 60 ° C. and a relative humidity of 75%. When the appearance and color development were observed, the appearance and color development were not observed.

  The obtained results are shown in Table 2 below.

Example 3
The thickness of each layer constituting the carbon dioxide gas indicator is as follows: anchor coat layer 0.5 μm, first carbon dioxide gas detection layer 0.4 μm, hydrophobic layer 0.5 μm, second carbon dioxide gas detection layer 0.4 μm, overcoat layer A carbon dioxide indicator having the same configuration as in FIG. 5 was obtained in the same manner as in Example 1 except that the thickness was changed to 1 μm.

  The obtained carbon dioxide indicator is put in a transparent outer casing made of a gas barrier base material, the inside is replaced with carbon dioxide 50% nitrogen 50%, the content containing sodium bicarbonate solution is enclosed, and the internal relative humidity is A 70% package was obtained.

  The resulting package was allowed to stand for 2 weeks under high temperature and high humidity conditions at room temperature of 60 ° C. and a relative humidity of 75%. When the appearance and color development were observed, the appearance and color development were not observed.

  The obtained results are shown in Table 2 below.

Example 4
A package was obtained in the same manner as in Example 3 except that the hydrophobic layer composition was the same as in Example 2.

  The resulting package was allowed to stand for 2 weeks under conditions of high temperature and high humidity of room temperature 60 ° C. and relative humidity 75%, and the appearance and color development were observed. No deterioration of the appearance and color development was confirmed.

  The obtained results are shown in Table 2 below.

Example 5
The composition of the hydrophobic layer was the same as in Example 2, the indicator was changed, and the anchor coating layer 0.5 μm, the first carbon dioxide gas detection layer 0.4 μm, and the first hydrophobic layer were formed on one side of the 12 μm thick polyester film 1. Example 1 except that the layer is 0.5 μm, the second carbon dioxide gas detection layer is 0.4 μm, the second hydrophobic layer is 0.5 μm, the third carbon dioxide gas detection layer is 0.4 μm, and the overcoat layer is 1 μm. Thus, a carbon dioxide indicator was obtained.

  FIG. 12 is a cross-sectional view showing the configuration of the multilayer indicator used in the fifth embodiment.

  As shown in the figure, the obtained multi-layer indicator 80 has a first carbon dioxide gas detection layer 41, a first hydrophobic layer 42, a second carbon dioxide gas detection layer 43, a second carbon dioxide detection layer 41 on an anchor coat layer (not shown). The hydrophobic layer 44 and the third carbon dioxide gas detection layer 45 are sequentially stacked.

  The carbon dioxide indicator according to Example 5 has the same configuration as that of FIG. 6 except that the indicator 80 is provided instead of the indicator 2.

  The obtained carbon dioxide indicator is put into a transparent outer casing made of a gas barrier substrate, the inside is replaced with carbon dioxide 50% nitrogen 50%, the contents containing the sodium bicarbonate solution are enclosed, and the internal relative humidity is 70. % Of the package was obtained. The resulting package was allowed to stand for 2 weeks under high-temperature and high-humidity conditions at 60 ° C. and 75% Rh, and the appearance and color development were observed. As a result, the appearance and color development were not deteriorated.

  The obtained results are shown in Table 2 below.

Comparative Example 1
A package was obtained in the same manner as in Example 1 except that the hydrophobic layer composition was changed as follows.

Hydrophobic layer composition:
6 parts by weight of polyvinyl acetal resin having a water solubility of 15% by weight and a water retention rate of 20% by weight, 4 parts by weight of isopropyl alcohol, 8 parts by weight of ethyl acetate, 5 parts by weight of methyl ethyl ketone, 12 parts by weight of toluene, anchor coat layer, overcoat Coat layer composition:
The resulting package was allowed to stand for 2 weeks under high-temperature and high-humidity conditions at room temperature of 60 ° C. and a relative humidity of 75%. When the appearance and color development were observed, water accumulated in the indicator part, resulting in poor color development.

  From this, it has been found that when a hydrophobic layer is formed using a resin having a hydrophobicity of greater than 10% by weight and a water retention rate of greater than 15% by weight, water droplets are generated, resulting in poor appearance.

  The obtained results are shown in Table 2 below.

Comparative Example 2
A package was obtained in the same manner as in Example 3 except that the hydrophobic layer composition was the same as in Comparative Example 1.

  The resulting package was allowed to stand under high temperature and high humidity conditions of 60 ° C. and 75% Rh for 2 weeks, and the appearance and color development were observed.

  The obtained results are shown in Table 2 below.

Comparative Example 3
The composition of the hydrophobic layer is the same as in Comparative Example 1, and the thickness of each layer constituting the carbon dioxide indicator is changed so that the anchor coat layer is 0.5 μm, the carbon dioxide gas detection layer is 0.3 μm, the hydrophobic layer is 1 μm, and the carbon dioxide gas detection layer is 0 A carbon dioxide indicator having the same configuration as that of FIG. 6 was obtained in the same manner as in Example 1 except that the thickness was 3 μm and the overcoat layer was 1 μm.

  The obtained carbon dioxide indicator is put into a transparent outer casing made of a gas barrier substrate, the inside is replaced with carbon dioxide 50% nitrogen 50%, the contents containing the sodium bicarbonate solution are enclosed, and the internal relative humidity is 70. % Of the package was obtained. The resulting package was allowed to stand for 2 weeks under high-temperature and high-humidity conditions at 60 ° C. and 75% Rh. When the appearance and color development were observed, it was difficult to recognize the color tone of the indicator because of the thin water pool.

  Accordingly, when the total thickness of the carbon dioxide gas detection layer is less than 0.8 μm, the color tone of the indicator is thin, it is difficult to recognize the change in color tone, the solubility in water is greater than 10% by weight, and the water retention rate is 15 It was found that water droplets were generated when a hydrophobic layer containing a resin larger than% by weight was used.

  The obtained results are shown in Table 2 below.

Comparative Example 4
Other than changing the thickness of each layer that constitutes the carbon dioxide indicator, the anchor coat layer is 0.5 μm, the carbon dioxide gas detection layer is 0.3 μm, the hydrophobic layer is 1 μm, the carbon dioxide gas detection layer is 0.3 μm, and the overcoat layer is 1 μm. Obtained the carbon dioxide indicator which has the structure similar to FIG. 6 like Example 1. FIG.

  Using the obtained carbon dioxide indicator, a package was obtained in the same manner as in Example 1.

  The resulting package was left to stand for 2 weeks under high temperature and high humidity conditions at room temperature of 60 ° C and relative humidity of 75%. It was.

  From this, it was found that when the total thickness of the carbon dioxide gas detection layer is less than 0.8 μm, the color tone of the indicator is thin and difficult to recognize.

The obtained results are shown in Table 2 below.

  Note that the present invention is not limited to the above-described embodiment as it is, and can be embodied by modifying the constituent elements without departing from the scope of the invention in the implementation stage. In addition, various inventions can be formed by appropriately combining a plurality of components disclosed in the embodiment. For example, you may delete a some component from all the components shown by embodiment. Furthermore, you may combine the component covering different embodiment suitably.

The front view showing the 1st example of the carbon dioxide indicator of the present invention Sectional view of FIG. Enlarged view of the indicator in FIG. Sectional drawing showing the structure of the 2nd example of the carbon dioxide gas indicator of this invention Sectional drawing showing the structure of the 3rd example of the carbon dioxide gas indicator of this invention Sectional drawing showing the structure of the 4th example of a carbon dioxide indicator The figure showing the 1st example of the gas replacement packaging body concerning this invention The figure showing the 2nd example of the gas replacement packaging body concerning this invention The figure showing the 3rd example of the gas replacement packaging body concerning this invention The figure showing an example of the structure of the carbon dioxide gas indicator which can be used for the 3rd example of the gas replacement packaging body concerning this invention Sectional drawing showing the example which applied the 4th example of the carbon dioxide gas indicator concerning this invention to the exterior body of a package Sectional drawing showing an example of the instruction | indication part used for this invention

Explanation of symbols

    DESCRIPTION OF SYMBOLS 1 ... Support body, 2,90 ... Instruction | indication part, 3 ... Carbon dioxide gas indicator, 5,73 ... Carbon dioxide gas permeable film, 8 ... Coating layer, 10, 18, 50, 60, 70, 80 ... Carbon dioxide gas indicator, 11 , 14, 16 ... containers, 12 ... exterior, 13 ... carbon dioxide containing gas, 17 ... ink layer, 20, 30, 40 ... packaging, 31 ... laminate, 32 ... gas barrier layer, 33 ... protective film, 35 , 41 ... first carbon dioxide gas detection layer, 36, 42, 44 ... hydrophobic layer, 37, 43 ... second carbon dioxide gas detection layer, 45 ... third carbon dioxide gas detection layer, 51 ... anchor coat layer, 52 ... Overcoat layer, 53 ... first anchor coat layer, 54 ... second anchor coat layer, 55, 81 ... nylon film, 56, 74, 82 ... adhesive layer, 57, 83 ... alumina-deposited polyester film, 71 ... Charcoal Gas-impermeable film, 75 ... sealant layer

Claims (4)

A support;
Provided on the support, at least two or more carbon dioxide detection layers formed using a carbon dioxide detection ink composition containing a pH indicator, a binder, and a solvent, and at least interposed between the carbon dioxide detection layers. A carbon dioxide gas detection indicator comprising a multilayer indicator including a hydrophobic layer containing a resin having a solubility in water of 0 to 10 wt% or less and a water retention rate of 1 to 15 wt%,
An indicator for detecting carbon dioxide, wherein the total thickness of the carbon dioxide detection layer is 0.8 μm or more, and the thickness of the hydrophobic layer is smaller than the total thickness of adjacent carbon dioxide detection layers.   2. The carbon dioxide gas detection indicator according to claim 1, wherein the hydrophobic layer has a thickness of 0.5 μm to 5 μm.   A packaging body, wherein the carbon dioxide indicator according to claim 1 or 2 is disposed in an exterior body in which a gas containing carbon dioxide gas is enclosed.   The package according to claim 3, wherein the relative humidity of the space in the exterior body is 50% to 100% in a storage environment at room temperature of 25 ° C and a relative humidity of 50%.

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