JPH066683B2 - Ink composition for oxidant detection - Google Patents

Description

TECHNICAL FIELD The present invention relates to an ink composition for detecting oxidant such as ozone in a constant atmosphere such as air or a room. More specifically, an oxidant detection ink composition which can be easily used and can obtain an oxidant detection indicator which can be easily used and can be clearly discriminated by applying it to a substrate such as paper or non-woven fabric by printing or the like and drying it. Regarding

(Prior Art) Recently, sterilization, disinfection, or sterilization in a constant atmosphere such as foods, articles such as surgical tools, or an operating room has come to be performed by utilizing the reactivity of ozone.

In such sterilization, disinfection or sterilization, it is necessary to detect not only the ozone concentration during the treatment but also whether or not the ozone concentration after the treatment is 60 ppb or less, which is an environmental regulation value, because of ozone toxicity.

In addition, oxidant concentrations in the air have also been detected for photochemical smog forecasts.

Conventionally, mainly for the measurement of ozone and oxidant Discoloration due to the reaction of is used.

As these devices or instruments, as a quantitative measurement, a gas containing ozone is introduced into a potassium iodide solution,
Optically measuring the degree of discoloration (colorless or yellowish brown) proportional to the amount of iodine generated with a colorimeter, and a simple type such as a detector tube and potassium iodide and starch on paper. Impregnated potassium iodide-starch paper is commercially available.

(Problems to be solved by the invention) However, an optical measuring device is very expensive,
It is not possible to measure easily, and there are problems in terms of cost and operation when measuring multiple points such as indoors.

The detector tube is rather simple and has high sensitivity, but it is relatively expensive, and it requires a device for manually aspirating the oxidant each time, or a device for automatically aspirating the oxidant, which is also problematic in terms of cost and operation. is there. Further, potassium iodide-starch paper is inexpensive and simple, but since discoloration starts at the same time when it is placed in an oxidant atmosphere, there is a problem that the color difference before and after discoloration is small and it is difficult to determine the detection state.

Note that this product cannot be used to detect low-concentration oxidants of several hundred ppb or lower due to its low sensitivity.

Further, the present inventors have found that a composition obtained by adding silica gel fine powder to an aqueous solution containing potassium iodide, water, and a water-soluble polymer is used as an indicator obtained by applying the composition to a substrate such as paper and drying the composition. At that time, it was found that the composition has a dramatically improved sensitivity as compared with the conventional product, and the above-mentioned composition was completed, which can detect even a low concentration of oxidant near the regulated value of 60 ppb or less.

However, since about 10 ppb of oxidant is usually contained in the atmosphere, it may react and discolor during the manufacturing process or before use due to its high sensitivity.

The problems related to the present invention are solved, and the state of detection can be clearly discriminated by suppressing the initial reaction, and even when used as a highly sensitive indicator, it may react and discolor during the manufacturing process or before use. It is an object to obtain an oxidant detection ink composition capable of obtaining a non-existent indicator.

(Means for Solving the Problems) As a result of earnest research to obtain the above composition, the present inventor has found that an appropriate amount of thiosulfate is added to an aqueous solution containing potassium iodide, water, and a water-soluble polymer. , Compared to conventional products,
The inventors have completed the present invention by discovering that the initial reaction to oxidants can be suppressed.

That is, the present invention comprises: a. Potassium iodide 0.20 to 40.00 parts by weight b. Water 25.0 to 96.00 parts by weight c. Water-soluble polymer 2.00-40.00 parts by weight d. It is characterized by containing 00.1 to 15.00 parts by weight of thiosulfate as an essential component.

The potassium iodide used in the present invention is a known chemical reaction. Is a discoloring component for detecting oxidant, and is used in an amount of 0.2 to 40.0 parts by weight (hereinafter simply referred to as "part"), preferably 1.0 part to 30.0 parts, relative to the total amount of the composition.

When potassium iodide is too small, the color difference of discoloration is small and the sensitivity is low.

On the other hand, when the amount is excessive, there is a disadvantage that the other components are relatively reduced and the coating suitability is deteriorated.

The water used in the present invention is used as a solvent,
Distilled water or pure water obtained by ion-exchange desalination is preferable, and tap water is not preferable because it contains chlorine and may react with potassium iodide to cause discoloration.

Water in the present invention is used in an amount of 25.0 to 96.0 parts, preferably 30.0 to 70.0 parts, based on the total amount of the composition.

If the amount of water is too small, the water-soluble polymer and potassium iodide are not sufficiently dissolved, and a uniform composition cannot be obtained.

On the other hand, when the amount is excessive, the viscosity of the composition becomes too low, the coating suitability is poor, and the sensitivity is poor.

The water-soluble polymer in the present invention is used as a binder and imparts an appropriate viscosity to the composition, and when the composition of the present invention is used to obtain an indicator, it is printed on a substrate such as paper. When the water is evaporated after application, it is dried and solidified to uniformly adhere and fix potassium iodide and thiosulfate described below to the substrate.

Examples of the water-soluble polymer include natural polymers such as sodium alginate, gum arabic, casein, pullulan, starch, and semi-synthetic polymers such as dextrin, methyl cellulose, ethyl cellulose, carboxymethyl cellulose, hydroxyethyl cellulose, polyvinyl alcohol, or synthetic polymers. Of these, white or highly transparent ones are preferable because they cause clear discoloration when used as an indicator.

These water-soluble polymers are used alone or in a plurality, and 2.0 to 40.0 parts, and preferably 5.0 to 30.0 parts are used with respect to the total amount of the composition.

If the amount of the water-soluble polymer is too small, the viscosity of the composition will be low and the coating suitability will be poor.

On the other hand, if the amount is excessive, the viscosity of the composition increases, the coating suitability deteriorates, and the sensitivity also decreases.

The thiosulfate in the present invention is used as a kind of desensitizer for suppressing the initial reaction between oxidant and potassium iodide. Thiosulfates include ammonium thiosulfate, potassium thiosulfate, calcium thiosulfate, magnesium thiosulfate,
Examples include strontium thiosulfate and sodium thiosulfate.

The thiosulfate is used in an amount of 0.01 to 15.0 parts, preferably 0.02 to 5.00 parts, based on the total amount of the composition.

The thiosulfate in the present invention exerts its effect even in a very small amount of 0.01 part, but if it is further reduced, the sufficient effect cannot be obtained.

If it is excessive, a uniform composition cannot be obtained due to its solubility, or the sensitivity becomes low.

In addition, in the present invention, silica gel as a sensitizer, a white pigment such as titanium oxide or a light-colored pigment or a water-soluble dye as a toning component, a surfactant or a preservative such as benzoic acid may be added as necessary.

In order to produce the composition of the present invention, potassium iodide, a water-soluble polymer, thiosulfate, and optionally silica gel and other additives are added to water, and if necessary, heated and stirred, The ink composition of the present invention is obtained as an aqueous solution in which the components are completely dissolved or uniformly dispersed.

(Function) The composition of the present invention can be applied to a base material such as paper by printing means and dried to obtain an oxidant detection indicator.

In the obtained indicator, in a given oxidant atmosphere, the onset of discoloration is delayed in proportion to the amount of thiosulfate as shown in the graph of FIG.

(The graph shows the case where thiosulfate is not contained.)Iodine generated in the Reduced to
The color of the thiosulfuric acid contained in the coating film of the indicator
Discoloration is suppressed in proportion to the amount of acid salt, and the onset of discoloration is delayed.
It

However, when the thiosulfate is consumed, iodine is generated by the oxidant and discoloration starts.

Therefore, since the state before the color change (white) is maintained for the time when the color change is suppressed, the color difference before and after the color change becomes clear, and the detection state can be easily determined.

Also, in an oxidant atmosphere with a relatively high concentration on the order of ppm, even an indicator with low sensitivity will discolor, but similarly the start of discoloration can be delayed, so the color difference before and after discoloration becomes clear and the detection state can be determined. Easier to do.

In particular, an indicator having high sensitivity is useful because it can suppress discoloration due to a slight amount of oxidant contained in the air during the manufacturing process or storage.

Furthermore, by selecting the amount of thiosulfate, it is possible to set the discoloration to start under arbitrary conditions in the process such as sterilization.

(Example) Hereinafter, the present invention will be described in detail with reference to Examples.

Example 1 5.0 parts of potassium iodide, 22 parts of dextrin (manufactured by Matsutani Chemical Co., Ltd., trade name: Pinetex # 2), 0.1 part of sodium thiosulfate
Part, 8 parts of silica gel fine powder (trade name: Aerosil 200 manufactured by Nippon Aerosil Co., Ltd.) are put into 64.9 parts of pure water, heated and stirred to form an aqueous solution in which the silica gel fine powder is uniformly dispersed, and cooled to have a waxy form. To obtain an oxidant detecting ink composition. The obtained composition was applied to a substrate made of paper by silk screen printing and dried to obtain a card-shaped, white indicator.

When this indicator was placed in an atmosphere with an ozone concentration of 100 ppb (room temperature), the initial discoloration was suppressed, and the color changed from white to yellowish brown within 10 minutes, and the detection state could be clearly discriminated.

Also, in an atmosphere of 60 ppb (room temperature), the color changed similarly in 30 minutes. However, the atmosphere of 15ppb (room temperature),
There was no change in 1 hour.

The graph of FIG. 1 shows the oxidant concentration of 100 in this example.
The graph shows the color change state in the ppb atmosphere, and the graph shows the color change state of the comparative example.

The composition of the comparative example was obtained by removing sodium thiosulfate from this example, and an amount of pure water equivalent to the removed sodium thiosulfate was 0.1.
It is a part added.

Since the comparative example had a high sensitivity, a slight yellowish discoloration was observed from the beginning, but in this example, there was no discoloration and the above-mentioned effect was confirmed.

Hereinafter, Examples 2 to 7 were obtained in the same manner, and the state of discoloration in a predetermined ozone atmosphere for each Example is shown in FIG.

In each case, the initial discoloration was suppressed and the detection state could be clearly discriminated.

Further, the compositions of Examples 1 to 5 to which high sensitivity was obtained by adding fine powder of silica gel also suppressed discoloration during manufacturing to obtain an indicator, and the effect was confirmed.

Example 2 Potassium iodide 5.0 parts Water 64.8 parts Dextrin (Pinetex # 2) 20.0 parts Magnesium thiosulfate 0.2 parts Silica gel fine powder 10.0 (Wako Pure Chemical Industries, Ltd., trade name: Wakogel B-0) Example 3 Potassium iodide 1.0 Part Water 71.99 parts Dextrin 20.0 parts (Matsuya Chemical Co., Ltd., trade name: Stacodex) Ammonium thiosulfate 0.01 parts Silica gel fine powder (Aerosil 200) 7.0 parts Example 4 Potassium iodide 20.0 parts Water 45.0 parts Dextrin (stacodex) 12.0 parts Potassium thiosulfate 3.0 parts Silica gel fine powder (Wakogel B-0) 20.0 parts Example 5 Potassium iodide 4.0 parts Water 62.9 parts Carboxymethylcellulose 8.0 parts (Daiichi Kogyo Seiyaku Co., Ltd., trade name: Serogen 7A) Calcium thiosulfate 0.1 Parts silica gel fine powder (Wakogel B-0) 25.0 parts Example 6 potassium iodide 3.0 parts water 89.9 parts dextrin (Pinetex # 2) 2. 0 parts Polyvinyl alcohol 5.0 parts (Kuraray, trade name: Poval 105) Sodium thiosulfate 0.1 parts Example 7 Potassium iodide 5.0 parts Water 67.0 parts Soluble starch (Wako Pure Chemical Industries) 25.0 parts Sodium thiosulfate 3.0 parts (Invention) (Effect) As described above, according to the present invention, it is possible to obtain an oxidant detection indicator which is inexpensive, can be used easily, and can clearly discriminate the detection state.

[Brief description of drawings]

FIG. 1 is a graph showing the discolored state of an indicator obtained using the composition of Example 1 of the present invention and the composition of Comparative Example. FIG. 2 is a table showing the discolored state of the indicators obtained by using the compositions of the examples of the present invention and the comparative example.

Claims (1)

[Claims] 1. A. Potassium iodide 0.20 to 40.00 parts by weight b. Water 25.0 to 96.00 parts by weight c. Water-soluble polymer 2.00-40.00 parts by weight d. An oxidant detecting ink composition, which comprises 0.01 to 15.00 parts by weight of a thiosulfate as an essential component.