JP4508807B2 - Oxygen detector - Google Patents

Description

The present invention relates to an oxygen detector. More specifically, the present invention relates to an oxygen detector that can identify the presence or absence of oxygen by a color change and is stable against light and heat.

  Conventionally, oxygen detectors using reversible color-changing organic dyes that change color reversibly by oxidation-reduction have been proposed. For example, solid oxygen detectors composed of thiazine dyes, azine dyes, oxazine dyes and other organic pigments and reducing agents are disclosed (Patent Documents 1 and 2). Also known is an oxygen indicator ink composition in which a thiazine dye or the like, a reducing saccharide, and an alkaline substance are dissolved or dispersed in a resin solution (Patent Document 3). Commercially available tablet-type oxygen detectors (for example, trade name: Ageless Eye, manufactured by Mitsubishi Gas Chemical Co., Ltd.) and oxygen detectors coated with an ink composition having an oxygen detection function (for example, trade name: Paper Eye, Mitsubishi Gas) (Chemical Co., Ltd.) is a functional product that simply indicates by color change that the oxygen concentration in the transparent packaging container is an oxygen-free state of less than 0.1% by volume. : Ageless, manufactured by Mitsubishi Gas Chemical Co., Ltd.) is used to maintain the freshness of food and the quality of medical drugs.

  However, conventional oxygen detectors have insufficient light resistance and storage stability, and may fade or discolor under light irradiation, and may brown or discolor under high temperatures. Therefore, in order to maintain a vivid color for a long period of time, it has a disadvantage that it must be stored under light shielding and at a low temperature. This tendency was particularly remarkable in the case of an oxygen detector coated with an oxygen detection ink. As an improvement, the present inventors have developed an oxygen detection composition (Patent Document 4) in which light resistance and storage stability are greatly improved by inserting an organic dye between the layers of the layered silicate. .

JP-A-53-117495 Japanese Patent Laid-Open No. 53-120493 JP 56-84772 A JP 2004-45365 A

However, the oxygen detector using the above-mentioned layered silicate has greatly improved storage stability, but has been found to have a slow response when placed in an oxygen-free state from an air atmosphere. .
An object of the present invention is to provide an oxygen detector excellent in light resistance and storage stability, and excellent in practicality and excellent in responsiveness to changes in oxygen concentration.

As a result of intensive studies in view of the problems of the prior art, the present inventors have found that a complex in which the oxygen detection composition is inserted into the layered silicate and an oxygen detection composition that is not inserted into the layered silicate. The present inventors have found that an oxygen detector containing both of the obtained mixtures has excellent light resistance, storage stability and responsiveness.
That is, the present invention provides an oxygen detection composition (1) comprising a complex in which a cationic surfactant, a reversible color-changing organic dye and a reducing agent are inserted between layers of a layered silicate, a reversible color-changing organic dye and a reduction. The present invention relates to an oxygen detector that is coated or printed with an oxygen detection composition (2) composed of a mixture of agents.

The present invention also provides an oxygen sensing composition (1) composed of the complex and an oxygen sensing composition (2) composed of the mixture, and further mixed with a binder to obtain oxygen sensing ink compositions, respectively. The present invention relates to an oxygen detector that is applied or printed in layers.
Furthermore, at least one of the oxygen detection composition (1) made of the complex and the oxygen detection composition (2) made of the mixture further relates to an oxygen detection body containing a non-color-changing colorant.

  The present invention provides an oxygen detector that is excellent in light resistance and storage stability and excellent in response to a decrease in oxygen concentration. The oxygen detector of the present invention has extremely high utility value in the field of oxygen-free storage such as food preservation and quality maintenance of medical drugs.

  The oxygen detector of the present invention is relatively excellent in light resistance under the conditions required for color change in an oxygen-free state and light irradiation, and has a good performance balance practically. In particular, from the base material side, an oxygen detector laminated in the order of the oxygen detection composition (1) composed of a composite and the oxygen detection composition (2) composed of a mixture has a color change response speed (blue → Since the blue color of the oxygen-sensing composition (1) composed of the complex is retained even when irradiated with light, it is excellent.

  The oxygen detector of the present invention comprises an oxygen detection composition (1) comprising a complex in which a cationic surfactant, a reversible color-changing organic dye and a reducing agent are inserted between layered silicate layers, and a reversible color-changing organic dye. And oxygen sensing composition (2) comprising a mixture of reducing agents is printed on a substrate. Alternatively, the oxygen detector of the present invention is obtained by mixing the oxygen detection composition (1) and the oxygen detection composition (2) with a binder to form an oxygen detection ink composition, which are applied or printed in layers. It is. The order in which the oxygen detection compositions are stacked may be (1) first or (2) first, or may be further stacked, for example, (1) (2) (1). In particular, an oxygen detector in which the oxygen detection composition (1) composed of a composite and the oxygen detection composition (2) composed of a mixture are laminated in this order from the substrate side is preferable.

  The layered silicate used in the oxygen sensing composition (1) comprising the composite of the present invention has a sheet structure in which atoms (including ions; hereinafter the same) groups are arranged on a plane to form a sheet structure. It is a silicate having a layered structure in which the sheet structure repeats in the direction. In addition, an inorganic material comprising a layer in which a tetrahedral sheet composed of silicon atoms, aluminum atoms and oxygen atoms and an octahedral sheet composed of aluminum atoms, magnesium atoms, oxygen atoms and hydrogen atoms are combined one-to-one or two-to-one. It is a layered compound. Further, the tetrahedral sheet may contain iron atoms in addition to the above atoms, and the octahedral sheet may contain iron atoms, or chromium atoms, manganese atoms, nickel atoms, and lithium atoms. In addition to water molecules, cations such as potassium ions, sodium ions, calcium ions or the like can be present as exchangeable cations between the layers of the layered compound.

  The type of layered silicate used in the present invention is preferably a smectite group, for example, a layered silicate (natural smectite) belonging to a natural smectite group such as montmorillonite and beidellite, saponite, hectorite, and soconite. Is mentioned. In addition, a layered silicate (synthetic smectite) belonging to the smectite group synthesized hydrothermally using an inorganic compound as a starting material can also be used. Among them, a preferred layered silicate is synthetic smectite.

  The cationic surfactant used in the oxygen-sensing composition (1) comprising the composite of the present invention is composed of an appropriate hydrophilic group and lipophilic group, and the molecule is ionized in water to form an organic cation. Is a surfactant. A typical example is a quaternary ammonium salt. Among them, a quaternary ammonium salt in which four lipophilic groups are bonded to nitrogen is preferable. Here, the hydrophilic group is a polar atomic group that can interact strongly with water, and generally contains atoms such as oxygen, nitrogen, and sulfur. This lipophilic group is a nonpolar atomic group having a strong affinity with oil and a very small interaction with water, such as chain and cyclic hydrocarbon groups, aromatic hydrocarbon groups, Examples include halogenated alkyl groups, organosilicone groups, and fluorocarbon groups.

  As the cationic surfactant used in the present invention, for example, cetyltrimethylammonium bromide, cetyltrimethylammonium chloride, stearyltrimethylammonium chloride, stearyltrimethylbenzylammonium chloride, distearyldimethylammonium chloride, distearyldimethylbenzylammonium chloride and the like are preferable. It is mentioned as a thing.

  The reversible color-changing organic dye used in the oxygen-sensing composition (1) composed of the composite of the present invention and the oxygen-sensing composition (2) composed of the mixture is reversible in response to the presence / absence of atmospheric oxygen. Plays the function of changing color. The reversible color-changing organic dye is an aromatic compound containing a long conjugated double bond system having π electrons that move easily in the molecule, and a compound whose color is reversibly changed by redox is used. As the reversible color-changing organic dye of the present invention, a redox indicator, a thiazine dye, an azine dye, an oxazine dye, an indigoid dye, a thioindigoid dye, or the like is preferably used. For example, methylene blue, new methylene blue, methylene green, barrier amine blue B, diphenylamine, ferroin, capri blue, safranin T, indigo, indigo carmine, indigo white, indirubin and the like can be mentioned. Preferred is a thiazine dye typified by methylene blue.

  The reducing agent used in the oxygen sensing composition (1) comprising the composite of the present invention and the oxygen sensing composition (2) comprising the mixture is the above reversible color-changing organic dye under conditions where the oxygen concentration is lower than in the atmosphere. For example, reducing sugars such as reducing monosaccharides and reducing disaccharides, ascorbic acid and salts thereof, dithionite and salts thereof, cysteine and salts thereof, and the like. Examples of the reducing monosaccharide include glucose, fructose, xylose, and examples of the reducing disaccharide include maltose. A preferred reducing agent is a reducing sugar, and a more preferred reducing agent is a reducing monosaccharide.

  In order to increase the reducing activity of the reducing agent, it may be desirable to further add a basic substance. As the basic substance, a hydroxide salt such as sodium hydroxide, potassium hydroxide or calcium hydroxide, or a carbonate salt such as sodium carbonate, potassium carbonate, calcium carbonate or sodium bicarbonate can be selected.

  In the oxygen detection composition (1) comprising a complex in which a cationic surfactant, a reversible color-changing organic dye, and a reducing agent are inserted between the layers of the layered silicate of the present invention, the conditions for the amount of each component charged are as follows: It is as follows. The cationic surfactant is 0.1 to 100 parts by weight, preferably 0.5 to 50 parts by weight, more preferably 1 to 10 parts by weight with respect to 1 part by weight of the layered silicate. . The reversible color-changing organic dye is 0.001 to 10 parts by weight, preferably 0.01 to 1 part by weight, based on 1 part by weight of the layered silicate. A reducing agent is 0.01 weight part-200 weight part with respect to 1 weight part of layered silicate, Preferably, it is 0.1 weight part-20 weight part.

  The composition ratio of the oxygen detecting composition (2) comprising the reversible color-changing organic dye and the reducing agent of the present invention is such that the reducing agent is 1 part by weight to 1000 parts by weight, preferably 1 part by weight of the reversible color-changing organic dye. 20 parts by weight to 400 parts by weight.

  The oxygen sensing composition (1) composed of the composite of the present invention and the oxygen sensing composition (2) composed of a mixture are mixed with a binder to improve the use performance such as printability and stability as ink. be able to. Suitable binders include one or more of cellulose derivatives such as ethyl cellulose, ethyl hydroxyethyl cellulose, cellulose acetylpropionate, butyral resin, polyester resin, acrylic resin, polyether resin, polyamide resin, petroleum resin and the like. A preferred binder is cellulose acetylpropionate.

  The binder is usually used after being dissolved or dispersed in an organic solvent or a solvent such as water. Preferred organic solvents include aromatics such as toluene and xylene, esters such as ethyl acetate and butyl acetate, ketones such as methyl ethyl ketone and methyl isobutyl ketone, alcohols such as methanol, ethanol and isopropyl alcohol, and ethylene glycol mono Ethers or glycols such as ethylene glycol are preferred, and more preferred organic solvents are ethyl acetate and isopropyl alcohol. The compounding ratio of the binder and the solvent is 5 to 100 parts by weight of the binder with respect to 100 parts by weight of the solvent.

  In the oxygen detection composition (1) comprising the composite of the present invention and the oxygen detection composition (2) comprising the mixture, 1 to 15 weights of polyhydric alcohol such as glycerin or ethylene glycol is added to the whole composition. %, Preferably 2 to 10% by weight. Thereby, there exists an effect that the discoloration property and decoloring responsiveness of the pigment when the oxygen detector comes into contact with oxygen are accelerated.

  As a method for producing the oxygen detection compositions (1) and (2) of the present invention, a known ink production method in which a pigment is mixed with a binder is used. For example, a layered silicate, a cationic surfactant, a reversible color-changing organic dye and a reducing agent (oxygen detection composition (1)), or a cationic surfactant, a reversible color-changing organic dye and a reducing agent (oxygen detection composition ( 2)) and the binder may be mixed (kneaded) with a kneading machine such as a sand mill, a ball mill, or a roll mill in a solution or dispersion. In particular, it is preferable to seal and mix in an oxygen-free state because deterioration of performance as an oxygen detection ink can be prevented. Hereinafter, the oxygen detection composition containing the binder may be referred to as an oxygen detection ink composition.

  The oxygen sensing composition (1) comprising the composite of the present invention and the oxygen sensing composition (2) comprising the mixture are preferably prepared in a two-component type. That is, one preferred embodiment of the present invention is a solution (1A solution) in which a layered silicate, a cationic surfactant, a reversible color-changing organic dye and a reducing sugar are dissolved or dispersed, and a solution in which a basic substance is dissolved or dispersed ( Oxygen detection composition (1) composed of a mixture with B liquid), a liquid (2A liquid) in which reversible color-changing organic dye and reducing sugar are dissolved or dispersed, and a liquid in which a basic substance is dissolved or dispersed (liquid B) Is an oxygen detector formed by applying or printing an oxygen detection composition (2) composed of a mixture of Further, the binder may be added to the 1A liquid and the 2A liquid, may be added to the B liquid, or may be added to the 1A liquid, the 2A liquid, and the B liquid. A method of mixing the B liquid prepared by dissolving or dispersing the basic substance and the binder with the 1A liquid and the 2A liquid each containing the binder is preferable. Liquid 1A and liquid B or liquid 2A and liquid B are mixed and used immediately before printing. By preparing the two-component type, not only the stability of the oxygen detection ink composition before printing but also the storage stability of the oxygen detection ink after printing can be improved.

  A preferable blending ratio of the binder in the 1A liquid and the 2A liquid is 0.01 to 10 parts by weight of the binder with respect to 1 part by weight of the reversible color-changing organic dye. A preferable blending ratio of the binder in the liquid B is 0.01 to 5 parts by weight of the binder with respect to 1 part by weight of the basic substance. A preferable mixing ratio of the 1A liquid or the 2A liquid and the B liquid is 0.05 to 50 parts by weight of the B liquid with respect to 1 part by weight of the 1A liquid or the 2A liquid.

  Furthermore, the color change can be made clear by separately adding a non-discoloring colorant different from the oxygen detection ink composition to the ink composition. Non-color-changing colorants include pigments and dyes that are less susceptible to redox reactions and have colors that contrast the colors that display the aerobic and non-oxygen states of reversible color-changing organic dyes. Can be used. When blue methylene blue is used as the reversible color-changing organic dye, examples of suitable non-color-changing colorants include red food additives Acid Red and Phloxine B.

  By applying or printing the oxygen-sensing ink composition of the present invention on a substrate as a character, figure, pattern, or the like by a printing method such as gravure printing, offset printing, letterpress printing, screen printing, or a coating method, etc. The oxygen detector can be used to display the presence or absence of oxygen in the container. As the substrate, small pieces such as paper and plastic, trays, inner surfaces of gas barrier containers, and surfaces of oxygen scavengers can be used.

  In printing, the oxygen-sensing ink composition of the present invention can be directly applied or printed on the surface of the substrate. Preferably, a sealant is applied or printed on the surface of the substrate, The oxygen detection ink composition of the present invention is applied or printed on, and an overprint agent is further applied or printed thereon.

  Hereinafter, the present invention will be described in detail by way of examples.

Example 1
Synthetic smectite (trade name: Smecton SA, manufactured by Kunimine Industries, Ltd., hereinafter referred to as “smectite”) 10.0 g, methylene blue 0.32 g, cetyltrimethylammonium chloride 6.4 g and methanol 15 mL are hybridized. The mixture was mixed with a mixer (manufactured by Keyence Corporation, HM-500) to obtain a pigment for oxygen detection ink. Using this pigment for oxygen detection ink, a 1A liquid for oxygen detection ink composition having the following composition (weight ratio) and a 2A liquid for oxygen detection ink composition having the following composition (weight ratio) were prepared. Furthermore, the B liquid for oxygen detection ink compositions of the following composition (weight ratio) was prepared. Moreover, the sealing agent and overprinting agent of the following composition (weight ratio) were prepared.

1A liquid Oxygen detection ink pigment 10.00 parts Phloxine B 0.05 parts by weight Cellulose acetylpropionate 6.24 parts by weight Fructose 15.15 parts by weight Ethylene glycol 22.30 parts by weight Ethyl acetate 23.18 parts by weight Isopropyl alcohol 23.08 parts by weight 2A solution Methylene blue 0.10 parts by weight Phloxine B 0.05 parts by weight Cellulose acetylpropionate 6.24 parts by weight Fructose 15.15 parts by weight Ethylene glycol 22.30 parts by weight Ethyl acetate 28.08 parts Isopropyl 28.08 parts by weight of alcohol

Liquid B Magnesium hydroxide 43.10 parts by weight Cellulose acetylpropionate 5.17 parts by weight Ethyl acetate 25.86 parts by weight Isopropyl alcohol 25.86 parts by weight

Sealing agent Cyclic rubber resin 10.00 parts by weight Magnesium hydroxide 30.00 parts by weight Toluene 30.00 parts by weight Cyclohexane 30.00 parts by weight Overprinting agent Cyclic rubber resin 19.42 parts by weight Sodium carbonate 91 parts by weight Toluene 38.83 parts by weight Cyclohexane 38.83 parts by weight

  The oxygen detection ink composition (1) was prepared by mixing 1A liquid and B liquid at an equal weight ratio, and the oxygen detection ink composition (2) was prepared by mixing 2A liquid and B liquid at an equal weight ratio. Subsequently, on a polypropylene synthetic paper (manufactured by Oji Paper Co., Ltd., trade name YUPO, thickness 70 μm), using a gravure printing machine, a sealant, an oxygen detection ink composition (1), an oxygen detection ink composition (2) and the overprinting agent are applied in this order at a rate of 2 g / m2, 2 g / m2, 2 g / m2, and 1 g / m2, respectively, and are cut into strips, which are tape-shaped having an oxygen detection ink application part. An oxygen detector was obtained.

The obtained oxygen detector was subjected to a discoloration test. That is, the oxygen detector was placed in a gas barrier transparent container, the inside of the container was replaced with nitrogen, and the container was hermetically stored at 25 ° C., and the change in the color of the oxygen detection ink application part was followed. The oxygen detector changed from pink to pink indicating anoxic state in 9 hours. When the container was opened, it quickly returned to blue indicating an aerobic state again by air exposure.

  A light irradiation deterioration test of the oxygen detector was performed. That is, the oxygen detection coating portion of the oxygen detection tape is irradiated with intense white light of 5000 lux using a fluorescent lamp as a light source at 25 ° C., 60% RH in the air, and a reversible color-changing organic dye by a visible spectrophotometer. The light resistance was evaluated by following the change in absorbance of the component methylene blue. The relative decrease in methylene blue absorbance after 6 hours of fluorescent lamp irradiation remained at 9%, and the color of the oxygen detector maintained a blue color indicating an aerobic state.

Example 2
Oxygen detection was carried out in the same manner as in Example 1 except that the order of applying the oxygen detection ink composition was changed to a sealant, oxygen detection ink composition (2), oxygen detection ink composition (1), and overprinting agent. A tape-like oxygen detector having an ink application part was obtained. When the discoloration test of the obtained oxygen detector was carried out in the same manner as in Example 1, the oxygen detector turned pink from pink to anoxic in 10 hours. When the container was opened, it quickly returned to blue indicating an aerobic state again by air exposure. When the light irradiation deterioration acceleration test of the obtained oxygen detector was performed in the same manner as in Example 1, the relative decrease rate of methylene blue absorbance after 6 hours of fluorescent lamp irradiation was 12%, and the color of the oxygen detector was aerobic. The blue color indicating the condition was maintained.

Comparative Example 1
Example 1 was carried out using only the oxygen detection ink composition (1). That is, in the same manner as in Example 1 except that the order of the oxygen detection ink composition and the like to be applied is the order of the sealing agent, the oxygen detection ink composition (1), the oxygen detection ink composition (1), and the overprinting agent. Thus, a tape-like oxygen detector having an oxygen detection ink application part was obtained. When the discoloration test of the obtained oxygen detector was performed in the same manner as in Example 1, it took 20 hours for the oxygen detector to change from blue to pink indicating anoxic conditions. When the container was opened, it quickly returned to blue indicating an aerobic state again by air exposure. When the light irradiation deterioration acceleration test of the obtained oxygen detector was performed in the same manner as in Example 1, the relative decrease rate of methylene blue absorbance after 6 hours of fluorescent lamp irradiation was 0%, and the color of the oxygen detector was aerobic. The blue color indicating the condition was maintained.

Comparative Example 2
Example 1 was carried out using only the oxygen detection ink composition (2). That is, in the same manner as in Example 1 except that the order of the oxygen detection ink composition and the like to be applied was a sealant, an oxygen detection ink composition (2), an oxygen detection ink composition (2), and an overprinting agent. A tape-like oxygen detector having an oxygen detection ink application part was obtained. When the discoloration test of the obtained oxygen detector was performed in the same manner as in Example 1, the oxygen detector became pink that showed anoxic state in 4 hours from blue. When the container was opened, it quickly returned to blue indicating an aerobic state again by air exposure. When the light irradiation deterioration acceleration test of the obtained oxygen detector was carried out in the same manner as in Example 1, the relative decrease rate of methylene blue absorbance after 6 hours of fluorescent lamp irradiation was 55%, although it was in an aerobic state. The color of the oxygen detector was light reddish purple indicating hypoxia.

Claims (4)

An oxygen sensing composition (1) comprising a complex in which a cationic surfactant, a reversible color-changing organic dye and a reducing agent are inserted between layers of a layered silicate;
An oxygen sensing composition (2) comprising a mixture of a reversible color-changing organic dye and a reducing agent,
An oxygen detector that is applied or printed on a substrate. The oxygen detector according to claim 1, wherein the oxygen detector composition (1) made of a composite and the oxygen detector composition (2) made of a mixture further contain a binder. The oxygen detector according to claim 1 or 2, wherein at least one of the oxygen detection composition (1) made of a complex and the oxygen detection composition (2) made of a mixture further contains a non-color-changing colorant. The oxygen according to any one of claims 1 to 3, wherein the oxygen sensing composition (1) composed of a composite and the oxygen sensing composition (2) composed of a mixture are applied or printed in this order from the base material side. Detecting body.