JP2022172809A - Composition for time-dependent color-changing indicator and time-dependent color-changing indicator including the same - Google Patents

Abstract

To provide a time-dependent color-changing indicator that keeps its coloring at a minimum for a while after its application but allows the coloring density to become sufficiently high at about a desired detection time, offering improved visibility, and a composition for use in the time-dependent color-changing indicator.SOLUTION: A composition for time-dependent color-changing indicators contains a color-changing dye, a base, a basic inorganic compound, a hydrophobic group-containing polyglycerol derivative and a binder resin. A time-dependent color-changing indicator has, on its base material, a color-changing layer formed from the composition.SELECTED DRAWING: None

Description

TECHNICAL FIELD The present invention relates to a composition for a time-changeable indicator and a time-changeable indicator using the same.

Various time-varying discoloration indicators using color tone change have been conventionally proposed. For example, products such as insect repellents, air fresheners, deodorants, and dehumidifiers change their quality and function depending on the environmental conditions at the time of storage and use, and the time spent in that environment (elapsed time). . Therefore, in order to manage the quality of these products, an indicator is required for grasping the environmental conditions in which the products are placed and the elapsed time.

Conventionally, as such a color change indicator over time, for example, using the pH change of the coating film due to carbonic acid generated by carbon dioxide in the air and water, a dye that changes with pH (acidic/basic) changes color over time. There is known an indicator that utilizes to do (see Patent Literature 1).
However, there is room for further improvement in order to obtain an indicator that suppresses color development for a while after application of the indicator, has sufficiently high color density near the desired detection time, and has better visibility.

Japanese Patent Application Laid-Open No. 2020-76050

The present invention has been made in view of the above, color development is suppressed for a while after applying the indicator, the color density becomes sufficiently thick near the desired detection time, and has better visibility, a time-dependent discoloration indicator and An object of the present invention is to provide a time-dependent discoloration indicator composition used therefor.

As a result of intensive research to achieve the above object, the present inventors have found a time-discoloring indicator composition containing a discoloration dye, a base, a basic inorganic compound, a hydrophobic group-containing polyglycerin derivative and a binder resin, and The present inventors have found that the above object can be achieved by making a color change indicator using it, and have completed the present invention.
That is, the present invention relates to the following composition for a time-changeable indicator and a time-changeable indicator using the same.

1. A composition for a time discoloration indicator, comprising a discoloration dye, a base, a basic inorganic compound, a hydrophobic group-containing polyglycerin derivative, and a binder resin.
2. Item 2. The composition for a time-discoloring indicator according to Item 1, wherein the base contains at least one selected from the group consisting of alkali metal hydroxides, ammonia and amines.
3. A composition for a time discoloration indicator, comprising at least one selected from the group consisting of alkali metal salts, ammonium salts and amine salts, a discoloration dye, a basic inorganic compound, a hydrophobic group-containing polyglycerin derivative, and a binder resin.
4. The hydrophobic group-containing polyglycerin derivative is at least one selected from the group consisting of polyoxypropylene polyglyceryl ether and polyglycerol polyricinoleate, for a time-discoloration indicator according to any one of items 1 to 3. Composition.
5. Item 5. The content of the hydrophobic group-containing polyglycerin derivative is 0.5 to 50% by weight based on 100% by weight of the total solid content of the composition for discoloration indicator over time, according to any one of Items 1 to 4. A composition for a time-varying discoloration indicator.
6. Item 6. The composition for a time-discoloration indicator according to any one of Items 1 to 5, wherein the basic inorganic compound comprises a hydroxide of a Group 2 element of the periodic table.
7. The binder resin includes petroleum hydrocarbon resins, vinyl resins, butyral resins, alkyd resins, epoxy resins, fluorine resins, silicone resins, polyester resins, coumarone resins, polyimide resins, alicyclic resins, acrylic resins, rosin resins, Item 7. The indicator for discoloration over time according to any one of Items 1 to 6, comprising at least one selected from the group consisting of rosin ester resin, ketone resin, hydrogenated ketone resin, cellulose resin, and polyamide resin. Composition.
8. Item 8. The composition for a time-discoloring indicator according to any one of Items 1 to 7, further comprising a non-discoloring dye.
9. A time-changeable indicator having a color-change layer formed from the composition for a time-changeable indicator according to any one of Items 1 to 8 on a substrate.
10. including a substrate and a color change layer,
The discoloration layer contains at least one selected from the group consisting of alkali metal salts, ammonium salts and amine salts, a discoloration dye, a basic inorganic compound, a hydrophobic group-containing polyglycerin derivative, and a binder resin, a time-discoloration indicator. .
11. Item 11. The time-discoloring indicator according to Item 9 or 10, further comprising a non-discoloring layer.
12. Item 12. The time-change indicator according to any one of Items 9 to 11, further comprising an overcoat layer.
13. Item 9. A printed material having a printed layer formed from the time-changeable indicator composition according to any one of Items 1 to 8.

The composition for a time-changing indicator of the present invention and the time-changing color indicator using the same suppress color development for a while after applying the indicator, and the color density becomes sufficiently dark near the desired detection time, resulting in better visibility. can have

Hereinafter, the composition for a time-discoloring indicator of the present invention (hereinafter also simply referred to as "composition") and the time-changing color indicator using the same (hereinafter simply referred to as "indicator") will be described in detail.

(1) Time-Discoloration Indicator Composition The time-change color indicator composition of the present invention contains a color change dye, a base, a basic inorganic compound, a hydrophobic group-containing polyglycerin derivative, and a binder resin.
By having such a configuration, particularly by including a hydrophobic group-containing polyglycerin derivative, the composition of the present invention and an indicator using the same are suppressed in color development for a while after applying the indicator, and near the desired detection time The density of the developed color becomes sufficiently high, and it is possible to have better visibility.

(color change pigment)
The discoloration dye is not particularly limited as long as it is discolored by a base and restored by carbonic acid generated from carbon dioxide in the air and water, and examples thereof include basic dyes. Basic dyes are not particularly limited, but for example, diarylmethane-based basic dyes, triarylmethane-based basic dyes, azo-based basic dyes, nitrogen-containing heterocyclic compound-based basic dyes, polymethine-based basic dyes, etc. is mentioned.
One or two or more of the discoloring dyes may be used.

Among the above color change dyes, triarylmethane-based basic dyes are preferable from the viewpoint of acid-base color change, and triphenylmethane-based basic dyes (e.g., C.I. Basic Violet 1, C.I. Basic Violet 3, C.I. Basic Violet 4, C.I. Basic Red 9, etc.) are more preferable, and C.I. Basic Violet 3, C.I. Basic Violet 4, etc. are more preferable.

The content (solid content) of the discoloration pigment can be appropriately determined according to the type of the discoloration pigment, the desired hue, etc., but it is preferably 0.5 in 100% by weight of the total solid content of the composition for a time-discoloration indicator. ~30% by weight, more preferably 1 to 15% by weight. If the content of the discoloration pigment is less than 0.5% by weight, the color of the indicator after discoloration may become pale, and if it exceeds 30% by weight, the color of the composition and the initial color of the indicator The color of the discoloration layer) may become colored rather than colorless.

In the present specification, "100% by weight of the total solid content of the composition for a discoloration indicator over time" means a total of 100% by weight of the solid content of each component contained in the composition.

Here, the discoloration of the discoloration dye will be described by taking a triphenylmethane-based basic dye as an example of the discoloration dye.
The triphenylmethane-based basic dye itself is colored. When a base is added to this, the colored dye structure of the triphenylmethane-based basic dye changes to a colorless dye structure, and the mixture becomes colorless. However, when this colorless mixture is treated with an acid, the colorless dye structure of the triphenylmethane-based basic dye returns to a colored dye structure, resulting in a colored mixture. An example (for example, CI Basic Red 9) showing the change in the above dye structure is shown in the formula below.

In the present invention, by utilizing the above reaction, carbonic acid formed from carbon dioxide and water in the atmosphere acts as an acid, so that in the composition for a time-change indicator, the above-mentioned discoloration dye returns to the original colored dye structure. and can be restored.
In the present specification, the discoloration dye includes both a colored dye structure and a colorless dye structure.

Further, the composition for a time-discoloration indicator of the present invention includes at least one selected from the group consisting of alkali metal salts, ammonium salts and amine salts, a discoloration dye, a basic inorganic compound, a hydrophobic group-containing polyglycerin derivative, and It contains a binder resin.
At least one selected from the group consisting of alkali metal salts, ammonium salts and amine salts in the composition is derived from the base when the discoloration dye and the base react to change the discoloration dye into a colorless dye structure. is.

(base)
By containing a base, the composition for a time-discoloring indicator of the present invention can cause a chemical change in the discoloration dye, change a colored dye structure to a colorless dye structure, and make the composition colorless. can.
The base is not particularly limited as long as it changes the color of the discoloring dye, but from the viewpoint of solubility in water or alcohol, for example, alkali metal hydroxide, ammonia, amine, and the like can be mentioned. The base can be used singly or in combination of two or more.
As the base, an alkali metal hydroxide is preferable from the viewpoint of solubility and the like.
Examples of the alkali metal hydroxide include, but are not particularly limited to, sodium hydroxide, potassium hydroxide, lithium hydroxide, and the like. From the viewpoint of ionization tendency, sodium hydroxide and potassium hydroxide are preferred.
Examples of the amine include, but are not particularly limited to, triethanolamine, polyethyleneimine, and the like.

The content (solid content) of the base is preferably 0.05 to 15% by weight, more preferably 0.1 to 5% by weight, based on 100% by weight of the total solid content of the composition for a discoloration indicator over time. be. If the content of the base is less than 0.05% by weight, the discoloration pigment is difficult to discolor, and the color of the composition and the initial color of the indicator may be difficult to become colorless. It may become difficult to dissolve in solvents.

Further, as described above, when the discoloration dye reacts with the base and the discoloration dye changes to a colorless dye structure, it is selected from the group consisting of alkali metal salts, ammonium salts and amine salts that are derived from the base. When the composition of the present invention contains at least one kind of base, its content is the same as the content of the above base.
The alkali metal salt, ammonium salt, and amine salt are salts corresponding to the discoloration dye used, and examples thereof include chloride salts and sulfonates.
Further, when an excess base is used for the discoloration dye, in addition to the above alkali metal salts, ammonium salts, and amine salts, a base (at least one selected from the group consisting of alkali metal hydroxides, ammonia and amines) may be included in the composition.

(Basic inorganic compound)
By containing a basic inorganic compound, the composition for a time-changeable indicator of the present invention can increase the color density when the composition changes color. In other words, it is considered that the basic inorganic compound acts as a discoloration auxiliary agent for the composition and can increase the color density.

The basic inorganic compound is not particularly limited as long as it has an action of adsorbing carbon dioxide and has low solubility in water and alcohol. Examples thereof include hydroxides of Group 2 elements of the periodic table.
Preferred examples of hydroxides of Group 2 elements of the periodic table include calcium hydroxide, magnesium hydroxide, barium hydroxide, and strontium hydroxide. The said basic inorganic compound can be used by 1 type(s) or 2 or more types.
In addition, since the basic inorganic compound has low solubility in water and alcohol, it is considered that it hardly acts on discoloration of the discoloration pigment. In addition, it is believed that the basic inorganic compound can adsorb carbon dioxide in the air, which reacts with water in the air to form carbonic acid, which can cause a recoloring reaction of the discoloring pigment. In addition, since the basic inorganic compound is white, it is thought that it also acts as an extender pigment and has the effect of making the color look darker when it is formed into a coating film.

The content (solid content) of the basic inorganic compound is preferably 1 to 50% by weight, more preferably 3 to 15% by weight, based on 100% by weight of the total solid content of the composition for discoloration indicator over time. If the content of the basic inorganic compound is less than 1% by weight, the degree of color development density may decrease. There is a risk that the adhesiveness with the material may be easily reduced. In addition, the content of the basic inorganic compound can be appropriately adjusted in consideration of other components.

(Hydrophobic group-containing polyglycerin derivative)
The time-changing indicator composition of the present invention contains a hydrophobic group-containing polyglycerin derivative, so that when an indicator containing the composition is applied, color development is suppressed for a while after application, and the desired detection time is near The color density can be increased with .
This is because the hydrophobic group-containing polyglycerin derivative stabilizes the colorless structure of the discoloration dye, so color development is suppressed for a while after the indicator is applied. However, since it absorbs water, it absorbs moisture in the air, which easily reacts with carbon dioxide in the air to form carbonic acid. In this way, for a while after the indicator is applied, the hydrophobic group-containing polyglycerin derivative acts to stabilize the colorless structure of the discoloration pigment (color development suppression effect), and then it is formed from moisture and carbon dioxide in the air. When the content of carbonic acid in the coating film increases, the effect of carbonic acid to return the discoloration pigment to the original colored dye structure exceeds the effect of suppressing the color development, and the color density increases at once.
In addition, the type and amount of addition of the hydrophobic group-containing polyglycerol derivative can be used to adjust the color development suppressing action and to adjust the time required to deepen the color development density.
Polyglycerin itself (not a polyglycerin derivative containing a hydrophobic group) is highly water-soluble, so rather than suppressing color development, it absorbs moisture in the air and reacts with carbon dioxide in the air to form carbonic acid. It is thought that the anti-coloration effect is difficult to develop because the action to suppress the color development progresses.

Here, the "desired detection time" corresponds to the preferred expiration date of the object (product) to which the indicator is applied, and can be appropriately set according to each object. For example, if the indicator is applied to an object that has a preferred expiration date of 24 hours, the desired detection time can be set to 24 hours (24 hours from the start of use of the indicator).
"Some time after application" means a certain period of time after application, and can be appropriately set according to each object to which the indicator is applied. For example, when the indicator is applied to an object whose expiration date is preferably 24 hours, the certain period of time after application can be about 8 hours from the start of use, but is not limited to this period of time.

The hydrophobic group in the hydrophobic group-containing polyglycerin derivative is not particularly limited, but preferably includes, for example, an oxyalkylene group having 3 to 4 carbon atoms (oxypropylene group, oxybutylene group, etc.), a ricinoleic acid ester group, and the like. be done.
The hydrophobic group-containing polyglycerol derivative is not particularly limited as long as it suppresses color development for a while after application of the indicator and can increase the color density near the desired detection time. Propylene polyglyceryl ether, polyglycerin polyricinoleate, and the like are preferred.
In the hydrophobic group-containing polyglycerin derivative, some or all of the hydroxyl groups of polyglycerin may be substituted with hydrophobic groups, and those in which some of the hydroxyl groups are substituted with hydrophobic groups are preferred.

The content (solid content) of the hydrophobic group-containing polyglycerin derivative is preferably 0.5 to 50% by weight, more preferably 2.5%, based on 100% by weight of the total solid content of the composition for a color-changing indicator over time. ~30% by weight. If the content of the hydrophobic group-containing polyglycerin derivative is less than 0.5% by weight, the above effects of the hydrophobic group-containing polyglycerin derivative may be difficult to manifest. is used for the discoloration layer of the indicator, the adhesiveness of the indicator to the base material may be likely to decrease.

(binder resin)
The binder resin is not particularly limited as long as it does not inhibit the acid-base reaction of the discoloration dye. , coumarone resins, polyimide resins, alicyclic resins, acrylic resins, rosin resins, rosin ester resins, ketone resins, hydrogenated ketone resins, cellulose resins, polyamide resins, and the like. Moreover, the said binder resin can be used by 1 type(s) or 2 or more types.

Among the above binder resins, rosin resins, rosin ester resins, ketone resins, hydrogenated products of ketone resins, and cellulose resins are preferred from the standpoint of high adhesion to indicator substrates and little effect on acid-base reactions. , and polyamide resins.
Although the rosin resin is not particularly limited, Pine Crystal KE-100, Pine Crystal KE-311, Pine Crystal PE-590, Pine Crystal KR-140 (manufactured by Arakawa Chemical Industries, Ltd.) and the like are preferred.
The rosin ester resin is not particularly limited. 135, and Pencel D-160 (manufactured by Arakawa Chemical Industries).
The ketone resin is not particularly limited, but examples include Ketone Resin K-90 (manufactured by Arakawa Chemical Industries), TEGO VARIPLUS AP (manufactured by Evonik), Hi-Luck 111 (manufactured by Hitachi Chemical), and POLYTONE K-90 (manufactured by Wally). etc. are preferably mentioned.
The hydrogenated ketone resin is not particularly limited, but preferably includes, for example, TEGO VARIPLUS SK (manufactured by Evonik) and Hilac 110H (manufactured by Hitachi Chemical).
Cellulose-based resins are not particularly limited as long as they are not water-soluble, and preferred examples include methylcellulose, ethylcellulose, and ethylmethylcellulose.
The polyamide resin is not particularly limited, but examples thereof include Vegichem Green V756, Vegichem Green V744, Vegichem Green V725 (manufactured by Tsuno Food Industry), Polymide S-40E (manufactured by Sanyo Chemical Industries), and the like. .

The content (solid content) of the binder resin is preferably 1 to 100% by weight of the total solid content of the composition for a time-changeable indicator, from the viewpoint of the adhesiveness to the base material of the indicator, the viscosity of the composition, etc. 90% by weight, more preferably 10 to 85% by weight.

Further, when the above polyamide resin is included as the binder resin, the polyamide resin functions not only as the binder resin but also as a discoloration aid, and can increase the color density of the composition and the indicator.
Polyamide resin has an amide group in the molecule, so although it is a hydrophobic resin, it has high water absorption, so it absorbs moisture in the air, which reacts with carbon dioxide in the air to form carbonic acid. It is thought that this carbonic acid is likely to cause a recoloring reaction of the discoloration pigment.

(non-discoloring pigment)
The compositions of the present invention may further contain non-discoloring pigments.
As used herein, a non-discoloring dye means a dye that does not discolor and is not decolorized by the above base. Examples of non-discoloring dyes include, but are not limited to, pigments and dyes. Examples of pigments include azo-based, phthalocyanine-based, perylene-based, and quinacridone-based pigments. Examples of dyes include azo-based, quinone-based, cyanine-based, phthalocyanine-based, and indigo-based dyes. From the viewpoint of visibility after discoloration, it is preferable to select a complementary color of the discoloration dye. The non-discoloring dye can be used singly or in combination of two or more.
When the non-discoloring pigment is included, the composition is no longer colorless because the discoloring pigment and the non-discoloring pigment are uniformly mixed in the composition. For example, if the discoloration pigment in the composition is blue and the non-discoloration pigment is yellow, an indicator using this composition will initially be yellow (because the base renders the discoloration pigment colorless) and over time will be green. (Because the color change pigment turns blue over time). Moreover, when a non-discoloring pigment is included, the initial color of the indicator preferably exhibits the color of the non-discoloring pigment.
When it contains a non-discoloring pigment, its content (solid content) is preferably 0.5 to 30% by weight in 100% by weight of the total solid content of the time-discoloring indicator composition from the viewpoint of visibility, More preferably 1 to 15% by weight.

(solvent)
The composition of the present invention may further contain a solvent.
The solvent is not particularly limited as long as it can dissolve discoloration dyes, bases, hydrophobic group-containing polyglycerin derivatives and binder resins. , ether-based, ketone-based, hydrocarbon-based, and glycol ether-based solvents. The solvent can be used alone or in combination of two or more.

The solvent may be appropriately selected according to the discoloration dye, base, solubility of the hydrophobic group-containing polyglycerin derivative and binder resin used, etc., and preferably has an appropriate drying speed.
Preferred examples of the solvent used for dissolving the discoloration dye, the hydrophobic group-containing polyglycerin derivative, and the binder resin include ketone-based solvents, alcohol-based solvents, and glycol ether-based solvents.
As the solvent used for dissolving the base, for example, water, alcohol (eg, ethanol, isopropanol, methanol, etc.) is preferable, and water is more preferable from the viewpoint of solubility of the base.

When a solvent is included, its content can be appropriately determined according to the type of discoloration dye, base, hydrophobic group-containing polyglycerin derivative and binder resin used, and is not particularly limited, but it improves the applicability of the composition. , From the viewpoint of adjusting the drying time of the composition, it is preferably 40 to 900% by weight, more preferably 60 to 600% by weight, based on 100% by weight of the total solid content of the composition for a time-discoloring indicator. .

(Additive)
The composition of the present invention may contain known additives as optional components in addition to the above components. Examples of additives include, but are not limited to, leveling agents, thickeners, dispersants, and the like.
Examples of the leveling agent include, but are not limited to, silicon oil.
As the thickening agent, those capable of imparting a thickening effect to the composition of the present invention and improving coatability are preferred. Examples of thickeners include silicate minerals and silicate composites.
As the dispersant, those capable of better dispersing the components in the composition of the present invention, particularly the basic inorganic compound, are preferred. Examples of dispersants include polymer dispersants (eg, Solsperse 41000, Solsperse 45000, Solsperse 54000, and Solsperse 66000 (manufactured by Lubrizol)), surfactants, and the like.
When the above various additives are included, the total content (solid content) is not particularly limited, but preferably 0.01 to 30% by weight in 100% by weight of the total solid content of the composition for a discoloration indicator over time, More preferably 0.1 to 15% by weight.

The preparation method of the time-changeable indicator composition of the present invention is not particularly limited, but it can be prepared, for example, by mixing and stirring the above respective components by a known method. In addition, the composition is preferably stored in a closed container immediately after preparation or used to form the color change layer of the indicator.

(2) Time-Discoloration Indicator The time-discoloration indicator of the present invention is characterized by having a discoloration layer formed from the composition of the present invention on a substrate.
In addition, the time-dependent discoloration indicator of the present invention includes a substrate and a discoloration layer, and the discoloration layer includes at least one selected from the group consisting of alkali metal salts, ammonium salts and amine salts, a discoloration dye, a basic inorganic compound, It contains a hydrophobic group-containing polyglycerin derivative and a binder resin.

(Base material)
The substrate is not particularly limited as long as it can form and support a discoloration layer. For example, metal or alloy materials (aluminum foil, stainless steel foil, tin foil, tin foil, etc.), plastics (polyester (various polyesters such as polyethylene terephthalate), cellophane, acetyl cellulose, ethyl cellulose, polyethylene, polypropylene, polyvinyl chloride, hydrochloric acid Films or moldings such as rubber, polystyrene, polycarbonate, polyvinyl alcohol, polyvinyl fluoride, polyamide, polyethylene fluoride, etc.), fibers (paper, wood materials, non-woven fabrics, woven fabrics, other fiber sheets), inorganic materials (ceramics, glass, concrete, gypsum), composite materials thereof, and the like can be used. The thickness of the base material can be appropriately set according to the type of indicator.

(discoloration layer)
A color change layer is formed from the composition of the present invention. Examples of the forming method include a method of forming a coating film of the composition of the present invention on a substrate. Specifically, the discoloration layer can be formed by applying the composition of the present invention on a substrate and then drying it.
The method for applying the composition of the present invention onto a substrate is not particularly limited, and examples include known coating methods such as spin coating, slit coating, spray coating, and dip coating; silk screen printing, gravure printing, offset printing, Known printing methods such as letterpress printing and flexographic printing can be used. In the present invention, coating includes concepts other than coating, such as printing and dipping.
After applying the composition of the present invention, the coating film is dried. Although the drying temperature is not particularly limited, it is usually preferably about 20 to 200°C, more preferably about 60 to 150°C.
The thickness of the discoloration layer in the indicator of the present invention is not particularly limited, but is preferably about 500 nm to 2 mm, more preferably about 1 to 100 μm, from the viewpoint of visibility and handling of printed matter.

Since the discoloration layer is formed by coating the composition of the present invention on a substrate and then drying it, the solvent derived from the composition does not exist in the discoloration layer at all or very little. As described above, in the composition, the discoloration pigment reacts with the base to render the discoloration pigment colorless. At least one selected from the group consisting of alkali metal salts, ammonium salts and amine salts (salt according to the dye used) generated at that time is a base (at least one selected from the group consisting of alkali metal hydroxides, ammonia and amines) 1) is thought to exist in the discoloration layer of the indicator before the discoloration starts.
Further, in the composition to be used, when an excess base is used with respect to the discoloration dye, in addition to the above alkali metal salts, ammonium salts, and amine salts, bases (from the group consisting of alkali metal hydroxides, ammonia and amines at least one selected) may be included in the discoloration layer of the indicator before the discoloration starts.
The content (solid content) of each component in the discoloration layer is preferably the same as the content (solid content) of each component in the composition described above.

(Non-discoloration layer)
The indicator of the present invention can also have a non-discoloring layer as an underlayer in order to enhance the visibility of the discoloring layer. The non-discoloring layer is not particularly limited as long as it does not affect the acid-base reaction in the discoloring layer, and can be formed of a composition containing pigments and/or dyes.
Examples of pigments include azo-based, phthalocyanine-based, perylene-based, and quinacridone-based pigments. Examples of dyes include azo-based, quinone-based, cyanine-based, phthalocyanine-based, and indigo-based dyes.
The composition for the non-discoloring layer can contain a binder resin, an extender, a solvent, etc., if necessary. Examples of the binder resin, the extender, and the solvent include those similar to those described above, and each of them can be used alone or in combination of two or more.
The method for forming the non-discoloring layer is not particularly limited, and the same known coating method, printing method, and the like as those for the discoloring layer can be used. Also, the thickness of the non-discoloring layer can be appropriately set according to the type of the indicator.

Any combination of discoloration and non-discoloration layers may be used in the present invention. For example, the discoloration layer and the non-discoloration layer are formed so that the color difference between the discoloration layer and the non-discoloration layer can be distinguished only after the discoloration of the discoloration layer, or the color difference between the discoloration layer and the non-discoloration layer disappears only after the discoloration. It can also be formed to In the present invention, it is preferable to form the discoloration layer and the non-discoloration layer so that the color difference between the discoloration layer and the non-discoloration layer can be distinguished only by discoloration.
In the case of distinguishing the color difference, for example, the discoloration layer and the non-discoloration layer may be formed so that at least one of characters, patterns and symbols appear only when the discoloration layer discolors. In the present invention, letters, graphics and symbols include all information that informs of color change. These characters and the like may be appropriately designed according to the purpose of use.
Also, the discolored layer and the non-discolored layer before discoloration may have different colors. For example, both may be made substantially the same color so that the color difference (contrast) between the discolored layer and the non-discolored layer can be identified only after discoloration.
In the present invention, as a preferred embodiment of the layer structure, for example, (i) an indicator in which a discoloration layer is formed adjacent to at least one main surface of a substrate, (ii) on the substrate, the non- A discoloration layer and the discoloration layer are formed in this order, the non-discoloration layer is formed adjacent to the main surface of the substrate, and the discoloration layer is formed adjacent to the main surface of the non-discoloration layer indicator being formed.

(overcoat layer)
The indicator of the present invention may have an overcoat layer, if desired.
The overcoat layer is arranged on the outermost layer of the indicator. Therefore, in both the case of having only a discoloration layer on the substrate and the case of having a discoloration layer and a non-discoloration layer on the substrate (for example, the layer configurations of (i) and (ii) above), the discoloration layer is adjacent to the An overcoat layer is then formed and positioned as the outermost layer of the indicator.
The overcoat layer can be used mainly for the following purposes. (a) Control the color change sensitivity of the indicator (suppress color change) by suppressing direct contact of the color change layer of the indicator with the outside air, (b) Promote color change of the indicator (especially color change in a low humidity environment) to improve the visibility of the indicator discoloration. In both cases (a) and (b) above, the formation of an overcoat layer can increase the coating strength of the discoloration layer.

The case (a) will be described below.
The overcoat layer is not particularly limited as long as it does not inhibit the acid-base reaction of the discoloring dye, and can be formed from a composition containing a resin.
Examples of the resin include those similar to the binder resin described above, and one or more of them can be used.

The composition for the overcoat layer may optionally contain a solvent and the like. For example, the above resin can be used by dissolving it in a solvent. Examples of the solvent include those similar to those described above, and one or more of them can be used.
A method for forming the overcoat layer is not particularly limited, and a known coating method, printing method, or the like similar to that for the discoloration layer can be used.
The thickness of the overcoat layer is not particularly limited, but is preferably about 500 nm to 2 mm, more preferably about 1 to 100 μm, from the viewpoint of handling printed matter.

Next, the above case (b) will be described below.
The overcoat layer is not particularly limited as long as it does not inhibit the acid-base reaction of the discoloring dye, and can be formed from a composition containing a resin.
As the resin, unlike the case of (a) above, for example, a vinylidene chloride-vinyl chloride-based special copolymer resin (eg, Ixan SGA-1 (manufactured by Solvay Specialty Polymers)) or a resin having an acid group or the like composition and the like. As the resin or resin composition having an acid group, the resin may have an acid group (a group that can act as an acid), or the resin composition may have an acidic substance having an acid group. good. The said resin can be used by 1 type(s) or 2 or more types.
The above resin used in the case of (b) has a function of suppressing the direct contact of the discoloration layer with the outside air and a discoloration promotion effect of the discoloration layer. In a humid environment, the discoloration promoting action of the resin becomes apparent, and in a high-humidity environment where carbonic acid tends to be produced, the action of the resin to suppress the production of carbonic acid becomes apparent.

In the case of (b), since the overcoat layer accelerates discoloration of the indicator (particularly in a low-humidity environment), the overcoat layer is formed on the outermost layer of the indicator when the indicator starts to be used. As a result, the start of use of the indicator and the start of discoloration of the indicator can be the same, so that a resin having an acid group, a resin composition, or the like can be used as the resin for the overcoat layer.

The composition for the overcoat layer may optionally contain a solvent and the like. For example, the above resin can be used by dissolving it in a solvent. Examples of the solvent include those similar to those described above, and one or more of them can be used.
A method for forming the overcoat layer is not particularly limited, and a known coating method, printing method, or the like similar to that for the discoloration layer can be used. From the viewpoint of forming the overcoat layer at the start of use of the indicator, it is preferable to use the coating method among the above methods.
Further, as a method of forming an overcoat layer at the start of use of the indicator, a method of applying the overcoat layer composition to the discoloration layer with a brush, a marker, a spray, etc. immediately before use; an overcoat printed on a separate film A method of attaching the layer to the discoloration layer immediately before use; a method of providing a spacer between the discoloration layer and the overcoat layer and pulling out the spacer immediately before use; Examples of spacers include, but are not limited to, plastic films.
The thickness of the overcoat layer is not particularly limited, but is preferably about 500 nm to 2 mm, more preferably about 1 to 100 μm, from the viewpoint of handling printed matter.

(adhesive layer)
The indicator of the present invention may have an adhesive layer on the back surface of the substrate (the surface opposite to the surface on which the discoloration layer is formed), if necessary. By having an adhesive layer on the back surface of the substrate, the indicator of the present invention can be reliably fixed to the object.
The component of the adhesive layer is not particularly limited, and examples thereof include acrylic, urethane, and silicone. Also, the thickness of the adhesive layer can be appropriately set according to the type of the indicator.

(indicator)
The shape of the indicator of the present invention is not particularly limited, and a wide range of shapes adopted for known indicators can be used.

The method for producing the indicator of the present invention is not particularly limited. An indicator can be manufactured by forming a color change layer thereon.

The obtained indicator is preferably stored in an absolutely dry space or in an absolutely dry atmosphere until use, and exposed to the atmosphere at the start of use. By storing the indicator in an absolutely dry atmosphere in this way, the initial color of the indicator can be maintained and the start of discoloration can be stopped, and the discoloration can be started when the indicator starts to be used.
The method for storing the indicator in an absolutely dry space or in an absolutely dry atmosphere is not particularly limited, but for example, the indicator is stored in a plastic (polyethylene terephthalate, polypropylene, polyester, etc.) bag vapor-deposited with metal (aluminum, etc.). and the like. In addition, by providing a film (material: polyethylene terephthalate, polypropylene, polyester, etc.) vapor-deposited with metal (aluminum, etc.) on at least the surface of the indicator having the color change layer, at least the surface of the indicator on the color change layer side is sealed. and a method of storing the indicator in a state close to absolute dryness. In this case, it is preferable to provide metal deposition films on both sides of the indicator. Further, there is a method of storing the indicator by combining the above methods.
The method of providing the metal-deposited film on one or both sides of the indicator is not particularly limited. Moreover, the adhesive layer is not particularly limited, and examples thereof include those similar to the adhesive layer described above.
The indicator of the present invention is stored as described above before use, and at the start of use, the indicator is removed from the metal-deposited plastic bag and/or the indicator is applied by peeling off the metal-deposited film. can be placed in the same environment as

The use of the indicator of the present invention is not particularly limited, but is preferably applied to products with expiration dates, such as foods, insect repellents, dehumidifiers, and deodorants.

(printed matter)
The printed matter of the present invention has a printed layer formed from the composition for a time-varying indicator.
Objects to be printed with the composition of the present invention include products that should be subject to product management. Examples of products include, but are not limited to, foods, insect repellents, dehumidifiers, deodorants, and the like, which have expiration dates.
When the composition of the present invention can be printed directly on the product, it can be printed directly, and when it cannot be printed directly on the product, it can be printed on the exterior bag or the like of the product.
When the printed matter is stored in an absolutely dry atmosphere, it can be stored in the same manner as the indicator.

EXAMPLES The present invention will be described in more detail below with reference to examples, but the present invention is not limited to the embodiments of these examples.

(Examples 1-5, Comparative Examples 1-4)
Raw materials having compositions shown in Table 1 below were mixed and stirred to prepare a composition for a time-discoloration indicator. This composition is applied to a polyethylene terephthalate (PET) film (Toyobo Espet corona-treated surface) using a coater to a thickness of 40 μm and dried (70° C. for 3 minutes) to form a discolored layer on the substrate. An indicator was produced.

In Table 1, each component other than the solvent shows the solid content. In addition, the explanation of each component listed in Table 1 is as follows.
Ethocel 4 (Dow Chemical): Ethyl cellulose superester A-75 (Arakawa Chemical): Special rosin ester resin Vegchem Green V756 (Tsukuno Foods Industry): Polyamide resin
SC-P750 (Sakamoto Yakuhin Kogyo): Polyoxypropylene polyglyceryl ether
SC-P1000 (Sakamoto Yakuhin Kogyo): Polyoxypropylene polyglyceryl ether poem PR-100 (Riken Vitamin): Polyglycerin polyricinolate
SC-E750 (Sakamoto Yakuhin Kogyo): Polyoxyethylene polyglyceryl ether Polyglycerin 03P (Daicel): Polyglycerin Solsperse 41000 (Lubrizol): Calcium hydroxide dispersant Dowanol PM (Dow Chemical): Propylene glycol monomethyl ether

Further, the following tests were conducted using the above indicators, and the results are shown in Table 1.
Color change test: The chromaticity of the initial color was measured. Next, the indicator was allowed to stand in an environment of 20° C.×65%, and the chromaticity of the discoloration layer of the indicator was measured at regular intervals to obtain the difference in chromaticity from the initial color. Since the PET film (Espette manufactured by Toyobo Co., Ltd.) is transparent, the color was measured on a white PET film (Crisper CA012 manufactured by Toyobo Co., Ltd.) in order not to be affected by the background. Further, the chromaticity was measured using a fluorescence spectrodensitometer FD-5 manufactured by Konica Minolta.

The chromaticity difference (color difference) ΔE*ab was obtained by calculating using the following formula.
ΔE*ab=[(L*2－L*1) ^2＋ (a*2－a*1) ^2＋ (b*2－b*1) ² ] ^1/2
The color difference between the initial color and the chromaticity after a certain period of time is L*1, a*1, b*1 for the initial color change layer of the indicator, and L* for the chromaticity after a certain period of time. 2, a*2, and b*2, respectively.
In addition, the color difference ratio of 24 hours/8 hours was obtained from the color difference after 24 hours/the color difference after 8 hours. If the color difference ratio of 24 hours/8 hours is 5 or more, the color density is deep and the visibility is excellent.

From the results in Table 1, in Examples 1 to 5, the color difference ratio at 24 hours/8 hours is as large as 5 or more, and the color difference after 24 hours is larger than the color difference ΔE*ab after 8 hours. Around (24 hours), the density of the developed color increased, and the visibility was excellent.
On the other hand, in Comparative Example 1, since the composition did not contain a hydrophobic group-containing polyglycerin derivative, the color difference after 24 hours was small, the color difference ratio of 24 hours/8 hours was also small, and the visibility was poor. Further, in Comparative Example 2 using a polyglycerin derivative containing no hydrophobic group, and in Comparative Examples 3 and 4 using polyglycerin itself, the 24-hour/8-hour color difference ratio was small and the visibility was poor.

Claims (13)

A composition for a time discoloration indicator, comprising a discoloration dye, a base, a basic inorganic compound, a hydrophobic group-containing polyglycerin derivative, and a binder resin. The composition for a time-varying discoloration indicator according to claim 1, wherein the base contains at least one selected from the group consisting of alkali metal hydroxides, ammonia and amines. A composition for a time discoloration indicator, comprising at least one selected from the group consisting of alkali metal salts, ammonium salts and amine salts, a discoloration dye, a basic inorganic compound, a hydrophobic group-containing polyglycerin derivative, and a binder resin. The hydrophobic group-containing polyglycerin derivative is at least one selected from the group consisting of polyoxypropylene polyglyceryl ether and polyglycerol polyricinoleate, the time-discoloration indicator according to any one of claims 1 to 3. composition. The content of the hydrophobic group-containing polyglycerin derivative is 0.5 to 50% by weight in 100% by weight of the total solid content of the composition for a time-discoloring indicator, according to any one of claims 1 to 4 A composition for a time-changeable indicator as described. The composition for a time-discoloration indicator according to any one of claims 1 to 5, wherein the basic inorganic compound comprises a hydroxide of a Group 2 element of the periodic table. The binder resin includes petroleum hydrocarbon resins, vinyl resins, butyral resins, alkyd resins, epoxy resins, fluorine resins, silicone resins, polyester resins, coumarone resins, polyimide resins, alicyclic resins, acrylic resins, rosin resins, Rosin ester resin, ketone resin, hydrogenated product of ketone resin, cellulose resin, and at least one selected from the group consisting of polyamide resin, color change indicator according to any one of claims 1 to 6. composition. The composition for a time-discoloring indicator according to any one of claims 1 to 7, further comprising a non-discoloring dye. A time-changing indicator having a color-changing layer formed from the composition for a time-changing indicator according to any one of claims 1 to 8 on a substrate. including a substrate and a color change layer,
The discoloration layer contains at least one selected from the group consisting of alkali metal salts, ammonium salts and amine salts, a discoloration dye, a basic inorganic compound, a hydrophobic group-containing polyglycerin derivative, and a binder resin, a time-discoloration indicator. . The time-changing indicator according to claim 9 or 10, further comprising a non-discoloring layer. The time-change indicator according to any one of claims 9 to 11, further comprising an overcoat layer. A printed matter having a printed layer formed from the time-changeable indicator composition according to any one of claims 1 to 8.