JPH06281642A - Composition of oxygen detecting agent - Google Patents

Abstract

PURPOSE:To provide the composition of an oxygen detecting agent which has an excellent discoloring property and stability and is hardly affected by carbon dioxide, ethanol vapor, etc., contained in atmospheres. CONSTITUTION:The composition is composed of hydrotalcites, oxidation- reduction pigment, and stannous compound. Hydrotalcites are compounds expressed by a general formula, Mg(1-x) Al x(OH)2.(CO3)x/2.mH2O (where, 0<=x<=0.33 and the (m) represents a positive integer). The stannous compound can be stannous chloride, stannous bromide, stannous iodide, stannous nitrate, stannous sulfate, stannous acetate, etc.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an oxygen detector composition which can be visually detected by discoloring when the oxygen concentration in an atmosphere falls below a certain value.

[0002]

2. Description of the Related Art Oxygen detecting agents are powder,
A solution, a gel, a molded article, or a sheet or a porous body impregnated with the solution has been proposed, and a tablet-shaped molded article is most widely used.

Among the oxygen detecting agents of this kind, those which can be practically used as an oxygen detecting agent capable of detecting a low concentration of oxygen in a deoxygenated package are currently a redox dye and a strong reducing agent. The combination is the only one.

Many proposals have hitherto been made on combinations of redox dyes and reducing agents, but basically, redox dyes such as methylene blue, reducing agents such as glucose, and alkaline earth metal hydroxides have been proposed. In general, an alkaline substance such as a substance is used as a main component, and an excipient, a red dye for color adjustment and the like are appropriately added thereto, and the mixture is tablet-molded.

As the reducing agent, reducing sugars such as glucose described above have been put to practical use, and a large number of substances such as ferrous compounds, stannous (tin) compounds, ascorbic acid and dithionous acid are also available. Among them, oxygen detecting agents using stannous compounds have been proposed, and Japanese Patent Publication No.
It is described in the official gazette.

The oxygen sensing agent described in the above publication contains a stannous compound (or ascorbic acid, erythorbic acid or a salt thereof) and a dye reduced by the stannous compound, and has a high stability and an alkaline substance. It has excellent features as an oxygen detector, such as high safety because it does not use.

[0007]

However, the oxygen detecting agent described in Japanese Patent Publication No. 56-24907 has a slow discoloration rate, discoloration is inhibited by the influence of carbon dioxide or ethanol vapor in the atmosphere, or oxygen is not detected. It has not been put to practical use because it has a drawback that the lower limit of detection increases.

On the other hand, the present applicant previously filed Japanese Patent Application No. 3-247.
No. 491, hydrotalcite
An oxygen sensing agent composition using a class of compounds and a reducing sugar has been proposed.

Since this composition has a high ability to adsorb hydrotalcites, the dye does not elute and the molded product does not collapse even when it is wet with water. Carbon dioxide, ethanol, acetic acid, etc. in the atmosphere will not hinder discoloration or increase the oxygen detection lower limit concentration.
Since the hydrotalcites themselves are extremely excellent excipients, the composition can be directly pressed, so that the tablet molding process can be simplified. It has extremely excellent performance such as high hardness of the molded product.

On the other hand, however, in this composition, since the redox dye is unstable and easily loses its oxidative color, if it is not stored in anoxic state before use, it will not develop color even when oxygen is present during use. There is. If oxygen is invaded while the oxygen detector is being used while being packaged in an anoxic state, if the packaging is incomplete and oxygen invades, the color will fade initially, but the It also has the drawback that it may not be distinguishable from the state.

An object of the present invention is to provide a novel oxygen detector composition which eliminates the respective drawbacks of the oxygen detector using hydrotalcites and reducing sugars and the oxygen detector using a stannous compound as a reducing agent. To provide things.

[0012]

The oxygen detector composition of the present invention is characterized by containing hydrotalcites, a redox dye and a stannous compound.

The stannous compounds used in the composition of the present invention include stannous chloride, stannous bromide, stannous iodide,
Examples include stannous nitrate, stannous sulfate, stannous acetate, etc., and water-soluble ones are particularly preferable.

The hydrotalcites used in the composition of the present invention have the following general formula:

[0015]

Embedded image Mg _(1-X) Al _X (OH) ₂ · (CO ₃ ) _{X / 2} · m H ₂ O (where x represents a number in the range of O <x ≦ 0.33, m Represents a positive integer) is preferable.

The redox dye used in the composition of the present invention is
Any dye may be used as long as the dye reversibly changes its hue between an oxidized state and a reduced state, and examples thereof include methylene blue, new methylene blue, thionine, methylene green, indigo carmine, safranine T, erythrosine, xylene blue, neutral red, toluidine. Examples thereof include dyes such as blue and Meldola blue, and among them, methylene blue is preferably used.

In the oxygen detector composition of the present invention, in addition to the above-mentioned constituents, a dye that does not discolor with the presence or absence of oxygen, a polyhydric alcohol, polyethylene glycol, or a highly water-absorbing material to make it easy to see the discoloration of the composition A discoloration accelerator such as a resin may be added. Further, if necessary, an excipient, a binder, a bulking agent, a lubricant, water and the like may be added, a reducing sugar may be used in combination, and an alkaline substance may be added depending on the case.

The mixing ratio of each component in the oxygen detector composition of the present invention is not particularly limited, but usually 15 to 98% of hydrotalcites and a redox dye.
0.001 to 0.1% and 2 to 10% stannous compound (anhydrous equivalent) are preferable. Further, excipients, bulking agents, etc. are 0-8
5%, a discoloration accelerator such as a super water-absorbent resin, and water are added as needed with 0 to 50% as a guide (% are all by weight).

The oxygen detector composition of the present invention has a fast discoloration rate and excellent stability, and further, discoloration is inhibited by the influence of carbon dioxide and ethanol vapor in the atmosphere, and the oxygen detection lower limit concentration is increased. It has been found that not only the drawbacks of the conventional oxygen sensing agent composition, such as no problem of being worn out, are overcome, but also an unexpected advantage such as the fact that the composition can be used even at a low temperature.

The oxygen detector composition of the present invention can be used in a powder state as it is, but it is convenient to use it by molding it into a tablet. It can also be used by dispersing it in water or the like and coating, printing or impregnating it on a paper, cloth, porous body or the like.

[0021]

EXAMPLES The present invention will be described below with reference to examples.

[Example 1] Methylene blue trihydrate 0.00
5 parts (parts are parts by weight; the same applies hereinafter), Red No. 106 0.
A solution of 004 parts dissolved in 5 parts of water was added to 80 parts of hydrotalcite [composition = Mg ₆ Al ₂ (OH) ₁₆ (CO ₃ ) .4
H ₂ O; trade name "Kyoward 500SH", manufactured by Kyowa Chemical Industry Co., Ltd.], and mixed, and then a solution of 6 parts of stannous chloride dihydrate dissolved in 10 parts of water is added dropwise to this. After mixing, 4 parts of magnesium stearate as a lubricant was further added and mixed. A pressure of 1 ton was applied to this powder for 5 seconds with a pressure molding machine to prepare a tablet-type oxygen detector having a thickness of about 2.5 mm and a diameter of 10 mmφ.

Example 2 A tablet-type oxygen detector was prepared in the same manner as in Example 1 except that 1 part of fructose was further added as a reducing saccharide.

Comparative Example 1 A tablet-type oxygen detector was prepared in the same manner as in Example 1 except that magnesium hydroxide was used in place of hydrotalcite as a carrier.

Comparative Example 2 A tablet-type oxygen detector was prepared in the same manner as in Example 1 except that 1 part of fructose and 2 parts of magnesium chloride were used instead of stannous chloride.

The results of examining the performance of these tablet-type oxygen detectors are shown in Table 1 below. In the table, the time indicated in the section of "Reducing color" is the detection agent under deoxygenated atmosphere (oxygen concentration 0.0
3V / V%) indicates the time required to change from blue-purple to pink when left in the atmosphere, and the time described in the "Oxidation color" section changes from pink to blue-violet when the detection agent is left in the air. It shows the time required for. In addition, the time described in the section of "bleaching" indicates the time until the color fades when the detection agent is left under the conditions described in the same section.

[0027]

[Table 1]

[0028]

According to the present invention, it is possible to provide an oxygen detector composition having the following effects.

The discoloration speed is fast.

It has excellent stability.

It can be used even at a low temperature.

Since the discoloration is not hindered and the oxygen detection lower limit concentration is not increased by the influence of carbon dioxide or ethanol vapor in the atmosphere, packaging in which air is replaced with carbon dioxide or various foods containing ethanol is used. Can be widely applied to.

Since the adsorbability of hydrotalcites is high, the dye does not elute and the molded product does not collapse even when wet with water.

Carbon dioxide, ethanol, acetic acid or the like in the atmosphere does not hinder discoloration or increase the oxygen detection lower limit concentration.

Since the hydrotalcites themselves are very excellent excipients, the composition can be directly pressed, so that the tablet forming process can be simplified.

The hardness of the molded product is high.

Claims (3)

[Claims] 1. An oxygen detector composition comprising hydrotalcites, a redox dye and a stannous compound. 2. The hydrotalcites are represented by the general formula: Mg _(1-X) Al _X (OH) _2. (CO ₃ ) _{X / 2} .m H ₂ O (where x is 0 An oxygen detector composition according to claim 1, wherein the oxygen detector composition is a compound represented by <a number in the range of x ≦ 0.33 and m is a positive integer. 3. The oxygen detector composition according to claim 1, wherein a water-soluble stannous compound is used.