JPS6313545B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a period display method for displaying the passage of a period by color change, and a period display device used in this method.

In factories, offices, homes, etc., preparations and articles with a fixed period of time are often used, such as refrigerator deodorizers (other examples will be shown later). However, in the case of this deodorizer, although the deodorizing ingredients such as activated carbon have absorbed a large amount of the bad odor peculiar to the refrigerator and no longer has any deodorizing ability, there is no change in appearance at all, so the user may not like it. However, it has the disadvantage of being used as is, which often results in unsanitary conditions such as a bad odor inside the refrigerator.

The present inventor conducted various studies on simple display methods and display devices for displaying the expiration of the expiration date of the above-mentioned deodorizers, etc., and as a result, the present invention was completed.

The present invention involves attaching a liquid to a material (hereinafter referred to as a "reversible color-changing material") that has a surface that changes color to a color different from the color when dry while the liquid is attached, and at the end of the volatilization period of the liquid. The present invention relates to a period display method characterized by displaying the period by changing the color of the surface.

The present invention also relates to a period indicator used in the period display method, and this indicator is configured such that a liquid is attached to the reversible color-changing material and the surface changes color when the liquid evaporates. It is characterized by the fact that However, the liquid may be applied during this period when the indicator is manufactured, or it may be applied immediately before the indicator is used. If a liquid is applied during the manufacture of a display device, it is best to cover it with an appropriate liquid volatilization prevention device (e.g., a protective film) to prevent undesired volatilization of the liquid until it is used, but the details will be discussed later. I will explain.

In the present invention, a certain amount of various types of liquid is attached to the reversible color-changing material and placed in a predetermined place (for example, in a living room or inside a refrigerator) until the color change of the color-changing material is completed due to volatilization of the liquid. For example, if a preliminary experiment shows that it takes 90 days for the color to change in the refrigerator, the period indicator will be used as a deodorizer for refrigerators with an expiration date of around 100 days. Can be used to indicate the period of the drug. Furthermore, since this period indicator utilizes the volatilization of liquid, the period until the color change is completed differs slightly for each period indicator, even for multiple period indicators manufactured under the same manufacturing conditions. It was found that the period variation was generally within about 10%. Therefore, for a deodorant with a shelf life of 100 days,
It is preferable to use a period indicator that has a period of 90 days until the color change is complete.

There are various reversible color-changing materials that can be used in the present invention, but one that is easily available is so-called water calligraphy paper, which is commercially available for practicing calligraphy and allows you to write black letters by soaking a brush in water. This sui-sho paper turns black when wet and returns to its original grey-white color when it dries, making use of the principle of light refraction.

Commercially available water calligraphy paper consists of colored pigments (particularly black pigments) and white or light colored pigments (such as silica, alumina, aluminum hydroxide, etc.) on a support such as paper.
(Wolin, bentonite, calcium carbonate, magnesium carbonate, calcium sulfate, etc.) are mixed with a suitable binder and applied, or a colored layer and a white or light colored pigment layer (hidden layer) are sequentially formed on the support. Manufactured by
Also, when water is applied, colors other than black (for example, red,
Suisho paper that changes color (such as blue) is also commercially available.

However, what should be noted here is that the hiding layer used in the present invention must not be dissolved in or altered by the liquid used for coloring. . For this purpose, the binder for forming the hidden layer and the white or light-colored pigment must be carefully selected. The same applies to colored layers.

Note that instead of the white or light-colored pigment layer, a transparent glass or plastic sheet with one side roughened to make it transparent can also be used.

This reversible color-changing material, such as water calligraphy paper, disappears quickly when exposed to water, but when it is immersed in a low-volatility liquid, it evaporates very slowly and remains attached to the surface for a long period of time, for example, about 90 days or more. It was found that the black discoloration remained for a longer period of time. Therefore, as shown in Table 1 in Example 1 below, various types of liquids were tested and found that they did not attack the material and were colorless.
Diethyl phthalate, which is odorless and harmless and has a boiling point of 298°C, is an example of a highly preferred liquid for period indicators with a shelf life of about 90 days in terms of surface retention, permeability to materials, workability, etc. It turned out to be. There are various other preferred liquids, examples of which are described in each example below.

When a low-volatile liquid was applied to a reversibly color-changing material, it evaporated extremely gradually, and the surface color became lighter over time, for example, from black to gray-black to white. This phenomenon is easy to understand, similar to the gradual decline in the deodorizing ability of a deodorizer. By choosing a liquid with volatility in mind, this color-changing device can be attached to a deodorant product as a period indicator. It was found that it was usable and that it was possible to set the desired deadline.

The period indicator of the present invention can be formed, for example, in the shape of a circular or rectangular paper strip, and this paper strip-shaped indicator can be attached to a surface to which it is attached, such as the surface of a container such as a deodorizer (see Fig. 4). ). FIG. 1 is a schematic cross-sectional view of an example of a period indicator of the present invention, and this period indicator 11 is made by sequentially laminating a colored layer 23 and a concealing layer 25 on a mount 21, and includes: After the liquid is attached to this (however, as described later, there may be cases where the liquid is not attached beforehand) the protective film 2
7 is coated and pasted onto the surface to be pasted 33 via the adhesive portion 31. The protective film 27 is removed during use. In order to prevent the period indicator 11 from coming off and falling, a recess 43 into which the indicator 11 can fit is provided on the surface 41 to be adhered (for example, the surface of a deodorant container) as shown in FIG. It is preferable to fit it in and cover it with a protective film 27. If there is no recess, attach the period indicator 11 on the surface 41 to be adhered as shown in FIG. 3, and place the protective film 2 on it.
It is preferable to cover the film 27 and bring the peripheral edge 28 of the film 27 into close contact with the surface 41 to be adhered. For a sheet-shaped deodorizer or the like, a period indicator 11 can be directly attached to the surface of the sheet 61 as shown in FIG. In either case, the surface of the display device during this period should be protected with a protective material, such as a protective film, as described above, to prevent liquid volatilization and contamination, and this protective film should be removed when using a deodorizer, etc. good.

When using in a humid place where condensed moisture may interfere with correct color change, it is best to use a period indicator whose surface is made of reversible color-changing material that has been hydrophobized in advance. .

As is clear from the above description, it is important that the time when the deodorizing agent loses its effectiveness substantially coincides with the time when the indicator changes color. For this purpose, we selected a liquid suitable for the deodorizer from among various liquids with different volatilities through preliminary experiments.
Good to use. In this case, as mentioned above, it is preferable to use a period indicator having a period approximately 10% shorter than the effective period of the deodorizer.

As described above, the period indicator of the present invention is particularly suitable for use as a deodorizer in refrigerators, where the temperature and humidity are almost constant throughout the four seasons, and the point at which the deodorizing ability is lost can be easily determined by visual inspection, and it can be replaced with a new one. It is convenient to be able to change it. You can also write text on the surface of this indicator, so if you write something like "Used" or "Expiration date has passed," the above text, which was hidden in black, will appear after the color changes (fading), making it even more convenient. Will.

The expiration date indicator of the present invention can also be advantageously used to display the expiration date of deodorizers and air fresheners (eg, gel-type air fresheners for living rooms) in living rooms, offices, or inside cars and trains. For example, in the case of sustained-release fragrances used in living rooms, conventionally there was no appropriate display means to indicate when the fragrance had evaporated, and the human sense of smell was the only way to determine when to replace the fragrance.
However, as has been shown in physiology, the human sense of smell is quite sensitive when first smelling a scent, but it quickly becomes accustomed to the scent, making it difficult to distinguish between its presence and absence. Therefore, it is convenient to use the period indicator of the present invention to visually determine when the fragrance has finished volatilizing.
The usage of the period indicator in this case is substantially the same as the usage of the period indicator of a refrigerator deodorizer.

In addition, this period indicator can be very advantageously used to indicate the period of an air freshener for a fan.
Conventionally, it has been troublesome to inspect the air fresheners because such fans and air fresheners are often placed in high places indoors, but according to the present invention, a period indicator can be pasted on the outside of the container, etc. This is very convenient as you can visually tell when the expiry date of the fragrance has expired.

Furthermore, in another specific example of the present invention, when indicating the period of preparations and articles (for example, fragrances, perfumes, insecticides, bactericides, etc.) that are used by vaporizing liquid, the main ingredients of these preparations and articles are indicated. The liquid agent is used as the "color-changing liquid" itself.
Therefore, in this case, there is no need to take the trouble to use another liquid to display the period. For example, in the case of fragrances, the present invention can be used to attach the liquid fragrance itself as a color-changing liquid to the expiration date indicator, and the color change of the indicator due to its volatilization makes it possible to visually tell when the expiration date of the fragrance has expired. It is more rational to make a distinction. In this case, the period indicator is not just a flat plate, but can also be formed in the shape of an animal, plant, or other object so that it also functions as an ornament. For example, as shown in FIG. 6, a period indicator 71 in the shape of an artificial rose flower is made;
It is possible to provide a concealing layer on the flower vase 73 (colored red, yellow, etc.) so that when the flower vase 73 is sprayed with an aromatic agent, the flower vase 73 turns bright red, yellow, etc. In the case of artificial rose flowers, it is effective to use a fragrance that smells like roses as an aromatic agent. When the aromatic agent finishes volatilizing, the flower vase 73 turns white, so the aromatic agent can be sprayed again at that time. Further, if such an artificial flower is immediately wrapped with a film or the like and sealed after being sprayed with a fragrance, the fragrance will not volatilize, and when the wrapping film is removed before use, the volatilization of the fragrance will begin.

Currently, there are so-called impregnated type fragrances on the market, which are made by impregnating an impregnating material with an aromatic agent and gradually releasing a fragrance. Install the
When impregnated with fragrance, the indicator is allowed to adhere to the fragrance by itself, or the material for impregnation (or a part thereof) is surface-treated from the beginning so that it also serves as a period indicator. It is better. This is very convenient because the expiry date of the impregnated type fragrance can be immediately determined with the naked eye by the discoloration of the indicator.

Furthermore, it is also useful to apply it to an electric mosquito repellent mat by the same method as in the case of the above-mentioned aromatic agent. That is, the period indicator of the present invention is attached to a pine impregnated with a liquid insecticide (for example, oily synthetic pyrethrin), and the indicator is allowed to adhere to the indicator by itself when impregnated with the insecticide, or the indicator is impregnated with a color. An insecticide may be impregnated into a mat that has a concealing layer formed on its surface so that it also serves as a period indicator. Both are colored when the insecticide is present, but the color changes when the insecticide is heated and volatilized, making it easy to tell when the insecticide has been volatilized.

Furthermore, the period indicator of the present invention can also be attached to a medical poultice. This is very convenient because the expiration date of the poultice can be visually recognized immediately.

If a spray perfume such as cologne is sprayed on the chest or the like after putting on clothes, the person often becomes accustomed to the smell of the perfume and does not know when to spray additional perfume. In such a case, it is advisable to attach the time indicator of the present invention to the back of the collar of clothing and spray perfume on this indicator as well. When the perfume has finished volatilizing, it can be immediately known by the discoloration of the indicator, which is very convenient because additional spraying of the perfume can be carried out at the appropriate time.

It is also possible to use a sheet-like period indicator, to which a fragrance has already been applied as a color-changing liquid, by attaching it to a part of clothing. After the period ends, the display device can be replaced with a new one. In this case, the sheet-like display device is very conveniently in the form of an adhesive tape or an adhesive label.

Example 1 A multi-layer paper made by coating a high-quality paper with a black layer on one side with a coating obtained from kaolin powder and a binder and drying it to form a concealing layer was prepared with a size of 25 mm in length and width.
It was cut into small pieces of ×25 mm and used as test pieces.
Each sheet weighed 0.25 g and had a thickness of 0.5 mm.

Add 0.03g of each of the liquids listed in the table below to each test piece.
I applied it one by one. Next, this test piece was hung over the width of a refrigerator (average temperature: 8°C; average humidity: 40%), and the state of discoloration was observed. The results of this experiment are shown in the table below. The surface of each sample piece dried within a short time after the liquid was applied, and the liquid did not adhere to the finger even when touched.

Table 1 Fluids Time until body discoloration occurs Absolute ethanol 2 minutes Ordinary water 10 minutes Isoamyl acetate 10 minutes Propylene glycol 15 hours Linalool 24 hours Geraniol 150 hours Lauryl alcohol 150 days Triethylene glycol 15 hours Glycerin 15 hours Diethyl phthalate ( DEP) 90 days Benzyl benzoate (BB) 150 days Isopropyl myristate (IPM) 150 days or more Silicone oil (KF-96) 150 days or more Isoeugenol acetate 40 days Liquid volume doubled from 0.03g to 0.06g Then,
Generally, the time it takes to complete discoloration is approximately 1.5 times longer.

If the thickness of the reversible color changing material is doubled by 0.5mm,
That is, when the thickness is set to 1 mm, the period until the color change is completed does not substantially change.

Example 2 Using diethyl phthalate (DEP) and benzyl benzoate (BB) as treatment liquids,
Two period indicators A and B were prepared according to the preparation method described in Example 1. The period until the color of these two types of period indicators A and B changes is approx.
90 days and about 150 days.

On the 86th day, the period indicator A (applied with DEP) affixed to refrigerator deodorizer P with a validity period of 100 days was affixed to cold storage deodorizer Q with a validity period of 165 days (5.5 months). The period indicator B (BB coating) completed discoloration on the 146th day.

Example 3 A container for refrigerator deodorizer (validity period: 150 days) was made of red plastic material, and part of its outer surface was
According to the present invention, a coating obtained from aluminum hydroxide powder and a binder is applied and dried to form a concealing layer (white), benzyl benzoate (BB) is applied to this, and a protective film is placed on top of this. Laminated and stored at room temperature for 6 months.

After heating, the protective film was removed and the product was placed in a refrigerator under the same conditions as in Example 2. On the 140th day, the hidden layer turned white, that is, the discoloration was completed.

Example 4 A period indicator (40 days) using isoeugenol acetate as a liquid was placed on the outside of a container of a gel-type room air freshener (validity period: 45 days, or 1.5 months).
The protective film was removed immediately before use. This period indicator is
Discoloration was completed on the 39th day.

Example 5 A period indicator using glycerin as the liquid was created. The color change was completed in about 10 hours at body temperature.

An anti-inflammatory patch (response time: 12 hours) with a period indicator attached was applied to the ankle. After 10.5 hours, the color change of the period indicator was completed.

Example 6 A concealing layer was formed on the flower pot 73 of the artificial rose flower (made of vinyl resin) 71 for living room shown in FIG. 6 using a coating agent using silica powder according to the present invention. The colors of the flower petals 73 were initially red and yellow, but both turned white due to the formation of the hiding layer. When used, the flower ben 73 turned bright red and yellow when sprayed with a rose-scented fragrance. This was used as an artificial flower containing an aromatic agent in the living room.
Approximately one month later, the color of the flower bezel 73 turned white due to volatilization of the fragrance. When you spray the fragrance again, the flower ben 73
The color changed again from white to bright red and yellow.

Similarly, when a concealing layer was formed on an artificial carnation flower according to the present invention and a blended fragrance with a carnation odor was sprayed, the same effect as described above was observed.

If such an artificial flower is sprayed with a fragrance and then immediately wrapped in a film and sealed, the fragrance will not volatilize, and when the wrapping film is removed before use, the volatilization of the fragrance will begin.

Example 7 (A) A period indicator that can be attached to the back of the collar of women's clothing was made. This period indicator was attached to the back of the collar of clothes, and when the perfume was sprayed, the period indicator was also sprayed. The period indicator allows you to immediately know when the fragrance has finished volatilizing, which is very convenient.

(B) A period indicator in the form of an adhesive label, which had been treated with a fragrance, its surface covered with a protective film, and an adhesive layer provided on its back, was attached to a part of the clothing. When the protective film was removed, the fragrance began to volatilize and emit a fragrance. The discoloration indicated that the fragrance had stopped volatilizing.
By replacing it with a new one, I was able to get it to emit the fragrance again.

Example 8 "Impregnated type fragrance" configured to impregnate a fragrance into an impregnated sheet placed in a container whose air permeability can be adjusted so that the fragrance is gradually released from this sheet over a fairly long period of time. is known, but
The period indicator described in Example 1 (without liquid applied) was attached to this impregnated sheet according to the invention. Therefore, when the impregnated sheet was impregnated with the fragrance, the fragrance automatically adhered to the period indicator. This fragrance-impregnated sheet was set in the inner box and the outer box was sealed, and when used, the outer box was pulled up to release it. The completion of the expiry date of the fragrance could be immediately determined by the discoloration of the expiration date indicator. In addition,
The fragrance used in this impregnated fragrance was a compounded rose, which was effective for approximately 50 days.

A fragrance-impregnated sheet similar to the sheet above is colored blue in advance, and a liniment prepared by mixing kaolin and gum arabic aqueous solution is applied to it, dried, and concealed. By forming a layer, the colored layer was hidden. to this,
When the sheet was impregnated with fragrance in the same manner as in the above case, the sheet developed a blue color. When this was left in an open state, the fragrance evaporated, and the end of the expiration date of the fragrance could be immediately known by the discoloration of the sheet.

Example 9 A dark blue colored vinyl tape was used as a colored layer, and a transparent film made opaque by roughening one side thereof was laminated thereon as a concealing layer. However, in this case, the colored layer was laminated so as to face the non-roughened surface of the opaque film. Looking at the laminate from above,
It appears very pale blue due to the diffused reflection from the roughened surface. When liquefied (for example, diethyl phthalate (DEP)) is applied to this, it changes to a vivid deep blue color.
A protective film is laminated thereon to obtain the period indicator of the present invention. It is more convenient to apply an adhesive to the back side of this laminated tape-shaped period indicator to form an adhesive tape. When using it, cut it to the appropriate size and paste it, remove the protective film and it will start working.
By using various liquids, various types of "desired period indicators" have been obtained. This period can be easily determined by preliminary experiments.

Example 10 Plate-shaped material (A) A plate-shaped material (A) was prepared by coloring impregnated paperboard made from Kotton Rinta (Rinta pulp) red and forming a concealing layer on its upper surface. However, the concealing layer of the lever was formed by preparing a coating solution by thoroughly kneading kaolin with a dilute aqueous solution of gum arabic in advance, applying this to the upper surface, and drying it.

Plate-shaped material (B) A plate-shaped material (B) was prepared by pasting a period indicator prepared in advance according to the present invention on the uncolored impregnated paperboard using gum arabic liquid. However, this period indicator was prepared by applying a coating agent [the same coating agent used in preparing the plate-shaped material (A) above] to the surface of colored paper (red) and drying it. It was hot.

Each of the plate-shaped materials (A) and (B) was impregnated with an oily synthetic pyrethrin (insecticide) using a method similar to a conventional impregnation method. The surface of the plate-shaped material turned red due to impregnation with this oily pyrethrin.

When this was placed on top of the heating element of an electric mosquito repellent, the red color changed to light pink when the pyrethrin had finished volatilizing (about 10 hours later), indicating that the volatilization of the agent had finished. The change in color was easily visible to the naked eye.

This specification describes in detail the use of the period display method and display device of the present invention for period display of deodorants, fragrances, spray perfumes, medical poultices, insecticides, bactericides, etc. However, the present invention can be advantageously used in various other fields,
For example, it can be used in the fields of children's toys and display displays.

[Brief explanation of the drawing]

FIG. 1 is a schematic cross-sectional view of an example of the period indicator of the present invention. FIG. 2 is a schematic cross-sectional view showing a state in which the period indicator is fitted and attached to a recess provided on a surface to be adhered, such as the surface of a container for deodorizing agent or the like. FIG. 3 is a schematic cross-sectional view showing a state in which this period indicator is adhered to a flat surface to be adhered. Figure 4 shows
It is a perspective view showing a state in which this period indicator is stuck to a container such as a deodorizer. FIG. 5 is a perspective view showing the period indicator attached to a sheet-like deodorizer or the like. FIG. 6 is a perspective view of an example of a period indicator in the form of an artificial rose flower. 11... Period indicator, 21... Mount, 23...
Colored layer, 25... Concealing layer, 27... Protective film, 28... Peripheral part of the protective film, 31... Adhesive part, 33... Surface to be adhered, 41... Surface of container such as deodorizer, etc. Adhesive surface, 43... Concavity, 51...
...Container for deodorant etc., 53...Vent hole or ventilation window, 61... Sheet-like preparation or article for deodorizer etc., 71... Period indicator in the shape of artificial rose flower, 73
...Hanaben.

Claims (1)

[Claims] 1. A material whose surface changes color to a different color while a liquid is attached to it than when dry (hereinafter referred to as a "reversible color-changing material")
1. A method for displaying a period of time, characterized in that a liquid is attached to the surface (referred to as . 2. Claim 1, characterized in that the reversibly color-changing material used is a material comprising a colored support or a support having a colored layer, and a concealing layer that is a diffuse reflection layer provided thereon. How to display the stated period. 3. Claim 1 or 2, characterized in that the liquid used is diethyl phthalate, benzyl benzoate or isoeugenol acetate.
The period display method described in section. 4. Claims 1 to 3, characterized in that the hiding layer is a layer containing a white or light-colored pigment, or a layer having a roughened surface.
The period display method described in any of the paragraphs. 5. Claims 1 to 4, characterized in that after applying a liquid to the reversible color-changing material, a protective material such as a protective film is coated thereon, and the protective material is removed immediately before use. The period display method described in either. 6. The period display method according to any one of claims 1 to 5, which is a method for displaying the shelf life of a deodorant. 7. The period display method according to claim 6, wherein the deodorizing agent is a deodorizing agent for refrigerators. 8. The period display method according to claim 6, wherein the deodorizing agent is a deodorizing agent for a living room, a vehicle, etc. 9. The period display method according to any one of claims 1 to 5, which is a method for displaying the shelf life of a fragrance. 10. The period display method according to claim 9, wherein the aromatic agent is an aromatic agent for a living room, a vehicle, or the like. 11. A period display method according to any one of claims 1 to 5, which is a method for displaying a period of time for medical poultices and insecticides/bactericides. 12 Apply a liquid to the reversible color-changing material, and
6. A period display method according to any one of claims 1 to 5, characterized in that the period display method is attached to an easily visible position on an article or a container thereof for which the period is to be displayed. 13. The period indication according to claim 1 or 2, characterized in that the liquid is used as the "color-changing liquid" itself to indicate the expiration date of a preparation or article that involves volatilization of the liquid. Method. 14. The period display method according to claim 13, wherein the preparation accompanied by liquid volatilization is a fragrance. 15. Articles in the form of plants, such as flowers, or animals or other objects, to indicate the expiration date of a fragrance adapted to spray them with a fragrance suitable for said animals, plants or objects. Claim 14, characterized in that a reversible color-changing material is present nearby or at least a part of the article is made of a reversible color-changing material, and the fragrance is used as the "color-changing liquid" itself. How to display the period. 16. The period display method according to claim 15, wherein the article has a flower shape and the fragrance has a flower scent. 17 Claim No. 1, characterized in that a reversible color-changing material configured to be attached to the back of the collar of clothing is used to display the volatilization point of perfume sprayed on the chest of a perfume user. Period display method described in Section 13. 18. The period display method according to claim 13, which is a method for displaying the validity period of a so-called impregnated type fragrance that is used by impregnating an impregnation material with a fragrance. 19 A structure in which a liquid is attached to a material (hereinafter referred to as a "reversible color-changing material") that has a surface that changes color to a different color from when dry while the liquid is attached, and the surface changes color when the liquid evaporates. A period indicator that displays a period by changing color. 20. The period set forth in claim 19, wherein the reversible color-changing material is formed by providing a concealing layer, which is a diffuse reflection layer, on a colored support or a support having a colored layer. Display device. 21. The period indicator according to claim 19 or 20, wherein the liquid used is diethyl phthalate, benzyl benzoate, or isoeugenol acetate. 22 Claim 19-, characterized in that the hiding layer is a layer containing a white or light-colored pigment or a layer having a roughened surface.
The period indicator according to any of paragraph 21. 23. Claim 19, characterized in that the liquid is applied to the reversible color changing material, and then a protective material such as a protective film is coated thereon, and the protective material can be removed immediately before use. -22nd
A period indicator described in any of the paragraphs. 24 Claim 19-2, which is used to indicate the expiration date of a deodorant
A period indicator as described in any of Section 3. 25. The period indicator according to claim 24, wherein the deodorizing agent is a deodorizing agent for refrigerators. 26. The period indicator according to claim 24, wherein the deodorizing agent is a deodorizing agent for a living room, a vehicle, etc. 27 Claim 19-2, characterized in that it is used to indicate the expiration date of a fragrance.
A period indicator as described in any of Section 3. 28. The period indicator according to claim 27, wherein the aromatic agent is an aromatic agent for a living room, a vehicle, or the like. 29. The period indicator according to any one of claims 19 to 23, which is used to indicate the period of a medical poultice or an insecticide/bactericide. 30 Applying a liquid to the reversible color-changing material, and
The period indicator according to any one of claims 19 to 23, characterized in that it is attached to an easily visible position on an article or a container thereof in which a period is to be displayed. 31 Claim 19, characterized in that the liquid is configured to be used as the "color-changing liquid" itself of a period indicator to indicate the expiration date of a preparation or article that involves volatilization of the liquid. or a period indicator as described in Section 20. 32. The period indicator according to claim 31, wherein the preparation accompanied by liquid volatilization is a fragrance. 33. A period indicator for indicating the expiration date of a fragrance configured to spray an article in the form of a plant, such as a flower, or an animal or other thing, with a fragrance suitable for said animal, plant or thing. 32. A period indicator according to claim 31, characterized in that it is a period indicator made in the shape of an article. 34. Claim 33, characterized in that the expiration date indicator for indicating the expiry date of an air freshener using a fragrance that smells like a flower is the expiration indicator made in the shape of a flower. Period indicator as stated. 35. The time period display according to claim 31, which is configured to be attached to the back of the collar of clothing, etc., in order to display the volatilization point of perfume sprayed on the chest, etc. of a perfume user. Ingredients. 36. The period indicator according to claim 31, which is used to indicate the expiration date of a so-called impregnated type fragrance that is used by impregnating an impregnation material with a fragrance.