JP4697410B2 - Low temperature oxygen detector composition - Google Patents

Description

  The present invention relates to an oxygen detector. More specifically, the present invention relates to a low-temperature oxygen detection agent that can identify the presence or concentration of oxygen by a change in color and has excellent responsiveness to a change in oxygen concentration.

  Conventionally, oxygen detectors using organic dyes that reversibly change color by oxidation-reduction have been proposed. For example, Patent Document 1 and Patent Document 2 disclose solid oxygen detectors composed of organic dyes such as thiazine dyes, azine dyes, and oxazine dyes, reducing agents, and basic substances. Patent Document 3 discloses 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. A commercially available oxygen detector (registered trademark Ageless Eye, manufactured by Mitsubishi Gas Chemical Co., Ltd.) is in the form of a tablet or the like in which a carrier is impregnated with an organic dye, a reducing agent, and an alkaline substance, and the oxygen concentration in the packaging container is 0. .Functional product that easily shows the color of deoxygenation of less than 1% by volume, maintaining the freshness of foods together with oxygen absorber (registered trademark AGELESS, manufactured by Mitsubishi Gas Chemical Co., Ltd.), and quality of medical drugs Used for holding.

  However, conventional oxygen detectors have insufficient reactivity at low temperatures, and the discoloration function decreases at low temperatures, so it takes time to confirm the deoxygenation state with the color of the oxygen detector. Had.

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

  An object of the present invention is to provide an oxygen detector having excellent responsiveness to oxygen concentration.

As a result of studying a method for solving the above-mentioned problems, the present inventors have completed the present invention.
That is, the present invention provides at least one organic acid or organic acid salt selected from the group consisting of citric acid, fumaric acid, malic acid, tartaric acid, gluconic acid and salts thereof with sodium, potassium, calcium, magnesium, and organic acid. It is a low-temperature oxygen detector composition comprising a complex in which a dye, a reducing agent and an alkaline substance are mixed as essential components.
In the present invention, it is a low-temperature oxygen detector composition comprising a layered silicate and a cationic surfactant as essential components, and the oxygen detector composition can be suitably in a liquid or solid form. There is an oxygen detector formed by impregnating a powder, solid or oxygen detector, and an oxygen detector formed by impregnating paper, cloth, or thread, which can be held in a carrier. In particular, an oxygen detection ink containing an oxygen detection agent composition and an oxygen detection body coated or printed with the oxygen detection ink are methods for detecting a change in oxygen concentration at low temperatures.

  ADVANTAGE OF THE INVENTION According to this invention, even if it is low temperature, the oxygen detection agent which can detect the state of a deoxygenation atmosphere quickly and stably is provided.

  The oxygen detection composition of the present invention is obtained by blending a specific organic acid or a salt thereof with a detection agent composition containing an organic dye, a reducing agent, and an alkaline substance as essential components in order to improve responsiveness. It is.

  Specific organic acids or salts thereof used for improving the responsiveness used in the present invention are citric acid, fumaric acid, maleic acid, malic acid, tartaric acid and gluconic acid, and sodium of these organic acids, Examples include salts with potassium, calcium, and magnesium. As the salt, for example, sodium citrate is monosodium hydrogen citrate, disodium hydrogen citrate, trisodium citrate, and the hydrogen salt thereof is also included. In the present invention, citric acid and sodium citrate are particularly preferable.

  The organic dye used in the present invention is an aromatic compound containing a long conjugated double bond system having π electrons that move easily in the molecule, and is a variable organic dye whose color is reversibly changed by redox. . As the variable organic coloring matter 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. Invariant organic dyes can also be used in combination with variable organic dyes.

  The reducing agent used in the present invention is a compound that reduces the above-mentioned organic dye under conditions where the oxygen concentration is lower than in the atmosphere, for example, monosaccharides such as glucose, fructose, and xylose, and reducing disaccharides such as maltose. , Ascorbic acid and its salt, dithionic acid and its salt, cysteine and its salt and the like.

  The alkaline substance used in the present invention is a compound that enhances the reducing activity of the reducing agent. Examples of the alkaline substance include hydroxides such as sodium hydroxide, potassium hydroxide, and calcium hydroxide, and sodium carbonate, potassium carbonate, and carbonate. Carbonates such as calcium and sodium bicarbonate can be selected.

  If desired, a layered silicate can be added to and mixed with the oxygen detector, thereby preventing a change in color tone of the dye. As an example of the layered silicate, for example, a smectite group is preferable. For example, a layered silicate (natural smectite) belonging to a natural smectite group such as montmorillonite and beidellite, saponite, hectorite, and saconite can be 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.

  When the layered silicate is added, it is preferable to add and mix a cationic surfactant. Examples of cationic surfactants formulated with layered silicates include, for example, cetyltrimethylammonium bromide, cetyltrimethylammonium chloride, stearyltrimethylammonium chloride, stearyltrimethylbenzylammonium chloride, distearyldimethylammonium chloride, distearyldimethylbenzylammonium A preferable example is chloride.

  In the oxygen detection composition of the present invention, the conditions for the amount of the organic acid (or organic acid salt), organic dye, reducing agent, and alkaline substance to be charged are 1 part by weight with respect to the organic acid (or organic acid salt). The organic dye is 0.001 to 10 parts by weight, preferably 0.01 to 1 part by weight. Similarly, the reducing agent is 0.01 to 100 parts by weight, preferably 0.1 to 10 parts by weight. Similarly, the alkaline substance is 0.001 to 1000 parts by weight, preferably 0.01 to 100 parts by weight. When adding the layered silicate, in addition to each component described above, 1 part by weight of the organic acid (or organic acid salt), the layered silicate is 0.001 to 1000 parts by weight, Preferably, the amount is 0.01 to 100 parts by weight, and the cationic surfactant is 0.001 to 1000 parts by weight, and preferably 0.01 to 100 parts by weight.

The oxygen detection composition of the present invention is obtained by mixing a solid or liquid organic acid, organic dye, reducing agent and alkaline substance, and optionally a layered silicate and a cationic surfactant using a mortar or the like. It is done. At this time, if necessary, a small amount of a solvent such as water or alcohol may be added to form a solution or a suspension.

The oxygen detection composition in the mixed state as described above is used as it is in a solid, liquid, or dried powder form as appropriate. It can be used as an oxygen detector in powder form, or can be molded and used as an oxygen detector in tablet form. Moreover, by impregnating a solution or suspension containing a solvent into paper, cloth, thread, etc., it can be used as an oxygen detector in the form of a film, sheet, thread, or the like.
Furthermore, by selecting an appropriate solvent, it can also be used as printing ink, and used as an oxygen detector printed on paper, cloth, film, etc. by methods such as gravure printing, letterpress printing, lithographic printing, and screen printing. Can

Examples 1-6
Oxygen in which 1.0 g of the organic acid (salt) shown in Table 1, 0.01 g of the variable organic dye methylene blue, 0.005 g of the unmodified organic dye Acid Red, 1.0 g of glucose and 0.01 g of sodium hydroxide are dissolved. 10 mL of the detection agent composition aqueous solution and 25 g of magnesium hydroxide were mixed in a mortar to dry the moisture, and the oxygen detection agent composition was impregnated with magnesium hydroxide. The obtained impregnated product was molded with a tableting machine to obtain an oxygen detector in the form of a blue-violet tablet (1 tablet 0.2 g).

The following discoloration test was performed using the tablet-type oxygen detector obtained in Examples 1-6.
Sealed in a gas barrier transparent container together with a commercially available oxygen scavenger (trade name: Ageless SA, manufactured by Mitsubishi Gas Chemical Co., Ltd.), stored under normal temperature conditions (25 ° C) or low temperature conditions (5 ° C), and zirconia The oxygen concentration in the container was tracked using a formula oximeter. The time from when the oxygen concentration in the container becomes less than 0.1% by volume until the color of the oxygen detecting agent changes to pink indicating that it is in a deoxygenated atmosphere is obtained as a response time delay at 25 ° C. or 5 ° C. It was.
The results are shown in Table 1.

  After the oxygen concentration in the container is less than 0.1% by volume, the oxygen detection agent shows a pink color in almost less than 1 hour under normal temperature conditions of 25 ° C, and under low temperature conditions of 5 ° C, The oxygen detector became pink after 5 or 7 hours. Under any of the conditions, it became a bluish purple indicating that it was an aerobic atmosphere immediately after exposure to air by opening. When this discoloration test operation was repeated using the same oxygen detector, the above results were reproduced, and it was found that the change was reversible depending on the oxygen concentration.

Comparative Example 1
A tablet-type conventional oxygen detector was prepared in the same manner as in Example 1 except that it did not contain an organic acid (salt), and the same test as in Example 1 was performed using this. The results are shown in Table 1.
After the oxygen concentration in the container is less than 0.1% by volume, it takes 4 hours for the oxygen detector to show a pink color indicating the deoxygenated atmosphere under the normal temperature condition of 25 ° C. However, at 5 ° C., which is a low temperature condition, it took 24 hours for the oxygen detector to turn pink. In addition, the color quickly changed to blue-violet upon exposure to air by opening.

  The oxygen detectors of the present invention (Examples 1 to 6) show a pink color that displays a deoxygenated atmosphere following the transition to an oxygen-free atmosphere, and the time required to change to pink even at 5 ° C., which is a low temperature condition. The delay was relatively short. Further, from the result of Comparative Example 1, the conventional oxygen detector that does not contain a specific organic acid (salt) has a time delay in changing to a pink color indicating a deoxygenated atmosphere after becoming an oxygen-free atmosphere. There was a significant time delay under low temperature conditions.

Table 1
Organic acid (salt) Response time delay (25 ° C) Response time delay (5 ° C)
Example 1 Citric acid 0 hour 5 hours Example 2 Sodium citrate 0 hour 5 hours Example 3 Gluconic acid <1 hour 7 hours Example 4 Sodium gluconate <1 hour 7 hours Example 5 Tartaric acid <1 hour 7 hours Example 6 Sodium tartrate Less than 1 hour 7 hours
Comparative Example 1 None 4 hours 24 hours

Example 7
Oxygen detection in which 1.0 g of sodium citrate, 15 g of synthetic smectite 5.0 g / L aqueous dispersion, 0.03 g of methylene blue, 2.5 g of fructose, 0.01 g of sodium hydroxide and 0.32 g of cetyltrimethylammonium chloride are dissolved 10 mL of the agent composition aqueous solution and 25 g of magnesium hydroxide were mixed in a mortar to dry the moisture, and the oxygen detector composition was impregnated with magnesium hydroxide. The obtained impregnated product was molded with a tableting machine to obtain an oxygen detector in the form of a blue-violet tablet (1 tablet 0.2 g).

  Using the tablet-type oxygen detector obtained above, the same discoloration test as in Examples 1 to 6 was carried out at a low temperature of 5 ° C. After the inside of the gas barrier container became a deoxygenated atmosphere with an oxygen concentration of less than 0.1% by volume, the color turned white after 8 hours.

Comparative Example 2
A tablet was molded with the same composition as in Example 7 except that sodium citrate was not added to obtain a blue tablet-type oxygen detector.
Using the obtained blue tablet type oxygen detector, the same discoloration test as in Example 7 was conducted under low temperature conditions of 5 ° C. After the inside of the gas barrier container was in a deoxygenated atmosphere with an oxygen concentration of less than 0.1% by volume, the color changed to white 48 hours later.

Example 8
5 g of an aqueous solution in which 1.0 g of sodium tartrate, 0.01 g of methylene blue, and 1.0 g of D-xylose are dissolved is mixed in a mortar, and 0.1 N NaOH is added dropwise to adjust the pH to 11.0. A blue film-shaped oxygen detector was obtained.
Using the obtained film-like oxygen detector, the same discoloration test as in Examples 1 to 6 was performed at a low temperature of 5 ° C. After the inside of the gas barrier container became a deoxygenated atmosphere having an oxygen concentration of less than 0.1% by volume, the color turned white after 6 hours.
It turned blue again quickly due to air exposure by opening. When this discoloration test operation was repeated using the same oxygen detector, the above results were reproduced, and it was found that the change was reversible depending on the oxygen concentration.

Comparative Example 3
In the same configuration as in Example 8, the filter paper was impregnated with a composition liquid to which sodium tartrate was not added to obtain a blue film-shaped oxygen detector.
Using the obtained blue film-shaped oxygen detector, the same discoloration test as in Examples 1 to 6 was performed at a low temperature of 5 ° C. After the inside of the gas barrier container became a deoxygenated atmosphere having an oxygen concentration of less than 0.1% by volume, the color changed to white after 24 hours.

  From the above results, the film-like oxygen detector of the present invention (Example 8) shows a pink color indicating the deoxygenated atmosphere following the deoxygenated atmosphere, and even at a low temperature of 5 ° C. The time delay to turn pink was relatively short. In addition, from the result of Comparative Example 3, the film-type oxygen detector having the conventional composition has a time delay in changing to pink indicating the deoxygenated atmosphere after becoming an oxygen-free atmosphere, and is greatly reduced at low temperature conditions. There was a time delay. From this, by adding at least one selected from organic acids and organic acid salts to the composition, the oxygen detector of the present invention has a short-time response to transition to a deoxygenated atmosphere at room temperature and particularly at low temperatures. It has been shown to improve.

Table 2
Organic acid Response time delay (5 ℃)
Example 7 Sodium citrate 8 hours
Comparative Example 2 None 48 hours
Example 8 Sodium Tartrate 6 Hours
Comparative Example 3 None 24 hours

Claims (9)

At least one organic acid or organic acid salt selected from the group consisting of citric acid, fumaric acid, malic acid, tartaric acid, gluconic acid and salts thereof with sodium, potassium, calcium and magnesium, organic dye, reducing agent and alkaline An oxygen detector composition comprising a complex in which a substance is mixed as an essential component. The oxygen detector composition according to claim 1, further comprising a layered silicate and a cationic surfactant as essential components. An oxygen detector according to claim 1, wherein the oxygen detector composition is solid and has a powder shape. An oxygen detector comprising: the oxygen detector composition according to claim 1 in a liquid state, and the oxygen detector composition held on a carrier. An oxygen detector formed by molding the oxygen detector according to claim 3 or 4. An oxygen detector comprising the oxygen detector composition according to claim 1 in a liquid state, wherein the oxygen detector composition is impregnated into paper, cloth or yarn. An oxygen detection ink comprising the oxygen detection agent composition according to claim 1. An oxygen detector coated or printed with the oxygen detection ink according to claim 7. A method for detecting a change in oxygen concentration based on a change in color of the detector using the oxygen detector according to any one of claims 5, 6, and 8.