Display medium

Abstract

To provide a display medium that is discolored in a state of being exposed in the presence of oxygen. This display medium has a discoloration layer on a substrate, the discoloration layer being formed with a redox dye, a food dye, a reducing sugar, an edible reduction promoter, an edible moisturizer, and an oxygen detection composition that contains an edible thickener. The oxygen detection composition that forms the discoloration layer is reversibly discolored in accordance with the presence of oxygen, so that the discoloration layer changes color upon transition from an oxygen-free state to an oxygen-present state. Therefore, when the discoloration layer is formed with a letter, a drawing pattern, a symbol or the like, information relating to a commodity constituted by the letter, drawing pattern, symbol or the like is highlighted by discoloration.

Claims

1. A display medium having a discoloration layer on a base material, wherein the discoloration layer changes color in response to the presence or absence of oxygen, and is formed of an oxygen detecting composition comprising an oxidation-reduction colorant, an edible colorant, a reducing sugar, an edible reduction promoter, an edible humectant, an edible thickener, and an adhesive material, the oxidation-reduction colorant is comprised in an amount of 0.03 to 0.5 mass % based on the total amount of the composition, a compounding ratio of the oxidation-reduction colorant to the edible colorant is 1:0.5 to 1:1.5, the edible thickener is comprised in an amount of 0.1 to 10 mass % based on the total amount of the composition, and the base material is constituted by plastic.

2. The display medium according to claim 1, wherein the discoloration layer forms at least one of character, design, and symbol.

3. The display medium according to claim 1, wherein the adhesive material is polyvinyl alcohol resin.

4. The display medium according to claim 1, wherein the adhesive material is vinylacetate resin.

5. The display medium according to claim 1, wherein the base material is constituted by an inkjet label base material.

6. The display medium according to claim 1, wherein the base material is constituted by CPP, PE or cellophane.

7. A packaging body, wherein the display medium according to claim 1 is sealed within the packaging body formed of a gas-barrier material.

8. The display medium according to claim 2, wherein the adhesive material is polyvinyl alcohol resin.

9. The display medium according to claim 2, wherein the adhesive material is vinylacetate resin.

10. The display medium according to claim 2, wherein the base material is constituted by an inkjet label base material.

11. The display medium according to claim 3, wherein the base material is constituted by an inkjet label base material.

12. The display medium according to claim 4, wherein the base material is constituted by an inkjet label base material.

13. The display medium according to claim 2, wherein the base material is constituted by CPP, PE or cellophane.

14. The display medium according to claim 3, wherein the base material is constituted by CPP, PE or cellophane.

15. The display medium according to claim 4, wherein the base material is constituted by CPP, PE or cellophane.

16. A packaging body, wherein the display medium according to claim 2 is sealed within the packaging body formed of a gas-barrier material.

17. A packaging body, wherein the display medium according to claim 3 is sealed within the packaging body formed of a gas-barrier material.

18. A packaging body, wherein the display medium according to claim 4 is sealed within the packaging body formed of a gas-barrier material.

19. A packaging body, wherein the display medium according to claim 5 is sealed within the packaging body formed of a gas-barrier material.

20. A packaging body, wherein the display medium according to claim 6 is sealed within the packaging body formed of a gas-barrier material.

Description

DESCRIPTION OF EMBODIMENTS

(1) Hereinafter, an embodiment of the display medium according to the present invention will be described.

(2) Although the present invention is described mainly by preferred representative examples, it is to be understood that the present invention is not limited to such examples and that modifications can freely be made without departing from the spirit of the present invention.

(3) A display medium according to the present invention has at least a discoloration layer on the base material thereof.

(4) This discoloration layer is formed by an oxygen detecting composition which reversibly changes color in response to the presence or absence of oxygen.

(5) Therefore, the discoloration layer also reversibly changes color in response to the presence or absence of oxygen.

(6) The oxygen detecting composition used in the display medium contains an oxidation-reduction colorant, an edible colorant, a reducing sugar, an edible reduction promoter, an edible humectant, and an edible thickener.

(7) The oxidation-reduction colorant selected is an aromatic compound including a long conjugated double bond system having electrons mobile in a molecule, which is a compound changing the color reversibly by oxidation-reduction.

(8) Examples of such a compound include:

(9) methylene blue, new methylene blue, neutral red, indigo carmine, acid red, safranine T, phenosafranine, Capri blue, Nile blue, diphenylamine, xylene cyanol, nitrodiphenylamine, ferroin, and N-phenylanthranilic acid.

(10) The content of the oxidation-reduction colorant is preferably set in a range that does not affect the safety of the contents, in particular, a range that is selected such that LD50 (median lethal dose) is 1180 mg/kg or less.

(11) Concretely, the content (contained amount) the oxidation-reduction colorant is 0.03 to 0.5 mass %, preferably 0.05 to 0.2 mass % based on the total amount of the composition.

(12) The edible colorant has an edible property and is added to visually strongly recognize discoloration in the oxygen-present state through color mixture with the oxidation-reduction colorant.

(13) The edible colorant is not particularly limited as long as it has an edible property, and can be appropriately selected from well-known synthetic edible colorants (food dyes) and natural edible colorants (food dyes).

(14) Examples include food red dyes such as Food Red No. 2, Food Red No. 3, Food Red No. 40, Food Red No. 102, Food Red No. 104, Food Red No. 106, and natural cochineal dye; food yellow dyes such as Food Yellow No. 4, Food Yellow No. 5, and natural safflower yellow dye; and blue dyes such as Food Blue No. 1 and Food Blue No. 2.

(15) One or more kinds of the above-described edible colorants may be arbitrarily mixed for use.

(16) The compounding ratio of the oxidation-reduction colorant to the edible colorant is 1:0.5 to 1:1.5, preferably 1:1 to 1:1.5.

(17) The reducing sugar has an edible property.

(18) Examples of the reducing sugar include ascorbic acid, ascorbate, erythorbic acid, erythorbate, arabinose, erythritol, galactose, xylose, glucose, mannose, fructose, and lactose.

(19) In this case, from the viewpoint of reducing power and solubility, it is preferred that fructose, in particular, D-fructose is selected.

(20) The reducing sugar is incorporated in an amount of preferably 1 to 20 mass %, more preferably 3 to 10 mass % based on the total amount of the composition.

(21) The reduction promoter to be used is not particularly limited as long as it has an edible property.

(22) Examples include alkali agents such as sodium hydroxide, potassium hydroxide, sodium carbonate, and potassium carbonate.

(23) The reduction promoter is incorporated in an amount of preferably 0.1 to 5 mass %, more preferably 0.5 to 3 mass % based on the total amount of the composition.

(24) The humectant to be used is not particularly limited as long as it has an edible property.

(25) Examples include glycerol and propylene glycol.

(26) It is preferable that the humectant is incorporated in an amount of preferably 1 to 30 mass %, more preferably 5 to 10 mass % based on the total amount of the composition.

(27) The thickener has an edible property and is added to obtain good and quick color development and discoloration to the base material, in particular, the base material constituted by paper.

(28) Examples of the thickener include dextrin, carrageenan, agar, cellulose (such as hydroxypropyl methylcellulose), and sodium alginate.

(29) The thickener is incorporated in an amount of 0.1 to 10 mass %, preferably 0.5 to 3 mass % based on the total amount of the composition.

(30) In addition, the oxygen detecting composition may contain an adhesive material.

(31) In the present invention, the adhesive material to be used may be edible adhesives, such as polyvinyl alcohol resin such as vinylformate resin, vinylacetate resin, and vinylpropionate resin.

(32) The adhesive material selected is preferably vinylacetate resin used for a food additive.

(33) When the adhesive material is added, good adhesion or adhesiveness is obtained to the base material, in particular, the base material constituted by plastic.

(34) The adhesive material is incorporated in an amount of preferably 1 to 15 mass %, more preferably 2 to 10 mass % based on the total amount of the composition.

(35) In the present invention, for example, in order to facilitate the application or print of the oxygen detecting composition, the oxygen detecting composition may be used in the form of being dissolved in a solvent, as needed.

(36) The solvent to be used is not particularly limited as long as it has an edible property.

(37) Examples of the solvent include water and ethanol.

(38) Incidentally, when the water is added to the ethanol, the amount of the water to use is preferably in the range of 10 to 70 mass %, more preferably 35 to 55 mass % with respect to the ethanol.

(39) Such an oxygen detecting composition forms a discoloration layer at the predetermined position on the base material through a well-known printing method or applying method, such as flexographic printing, gravure printing, offset printing, relief printing and screen printing.

(40) The printing method selected is preferably flexographic printing because good printability is obtained.

(41) In print or application, the discoloration layer may be constituted by patterns, such as character(s), design(s) or picture pattern(s), symbol, pattern(s) or marking(s).

(42) According to such structure, the discoloration layer, in which information relating to a commodity formed of the character, design, symbol or the like is printed or applied, is discolored after specific time passes upon transition from an oxygen-free state to an oxygen-present state.

(43) Thus, the information is emphatically displayed than before the discoloration.

(44) For the base material, a general base material, such as paper, synthetic paper, nonwoven fabric and a synthetic resin film, can be used in accordance with the purpose and usage form.

(45) The base material selected is preferably constituted by an inkjet label base material (a base material used for forming a label with an inkjet print head), polypropylene (CPP, OPP), polyethylene (PE), polyethylene terephthalate (PET), or cellophane because good coloring property and discoloration property are obtained, and color development and discoloration occur quickly due to an effect of the thickener contained in the oxygen detecting composition.

(46) The shape of the base material selected is not particularly limited, and may be in a sheet shape, a film shape, or the like.

(47) After the oxygen detecting composition is applied or printed to the base material, the surface of the base material may be overcoated by a well-known overcoating method to protect the surface.

(48) In such an display medium, the color tone of the discoloration layer varies, for example, between an oxygen-free state of being sealed in the gas-barrier container with a deoxidizer and an oxygen-present state of being taken out from the container by unsealing, so that the discoloration layer, which constitutes information relating to a commodity formed of the character, design, symbol or the like, is emphasized when the discoloration layer is discolored upon transition from an oxygen-free to an oxygen-present.

(49) Therefore, the display medium may be applied to, for example, a campaign label for informing only commodity purchaser about benefit information, a security label (alteration preventive label) capable of discriminating unsealing when a commodity is opened.

(50) In this case, the display medium may be used in a form wherein the discoloration layer is formed on the base material, concretely, in a form wherein the discoloration layer is formed on the front surface or rear surface of inner bag, card, seal, or the like, which is sealed within packaging body formed of a gas-barrier material and containing contents such as foods and pharmaceuticals, and in addition, for example, in a form wherein the discoloration layer is formed on the inner surface of a packaging material, which constitutes packaging body containing contents such as foods and pharmaceuticals and is used for the base material.

EXAMPLES

(51) Hereinafter, the present invention will be described in detail with reference to Examples; However, the present invention is not limited by these Examples.

Production Examples 1 and 2

(52) According to the composition of the following Table 1, components was admixed and stirred to obtain oxygen detecting compositions.

(53) TABLE-US-00001 TABLE 1 Composition of oxygen detecting composition (unit: mass %) Ratio Production Production Production Components Example 1 Example 2 Example 3 Methylene blue 0.07 0.10 0.20 Food Red No. 106 0.08 0.10 0.25 Fructose 7.00 5.00 10.00 Sodium hydroxide 1.50 2.00 3.00 Glycerol 5.00 7.00 10.00 Ethanol 40.42 52.00 38.90 Hydroxypropylmethyl 0.60 1.00 1.00 cellulose Water 45.33 32.80 36.65 Total 100.00 100.00 100.00

Examples 1 to 15

(54) According to the following Production method based on the structure shown in the following Table 2, display mediums were prepared.

Production Method

(55) On various base materials, the oxygen detecting composition obtained in Production Example 1 above was printed at a ratio of 4 g/m.sup.2 with a flexographic printing machine (manufactured by MPS Systems B.V., EC330) to form a discoloration layer and then obtain sheet-shaped display medium having the discoloration layer.

(56) TABLE-US-00002 TABLE 2 Various display mediums Oxygen detecting composition Base material Example 1 Production Example 1 CPP sheet Example 2 Production Example 1 OPP sheet Example 3 Production Example 1 PE sheet Example 4 Production Example 1 PET sheet Example 5 Production Example 1 Cellophane sheet Example 6 Production Example 2 CPP sheet Example 7 Production Example 2 OPP sheet Example 8 Production Example 2 PE sheet Example 9 Production Example 2 PET sheet Example 10 Production Example 2 Cellophane sheet Example 11 Production Example 3 CPP sheet Example 12 Production Example 3 OPP sheet Example 13 Production Example 3 PE sheet Example 14 Production Example 3 PET sheet Example 15 Production Example 3 Cellophane sheet

Test Example 1 Evaluation of Discoloration Property

(57) The display mediums obtained in Examples 1 to 15 above were subjected to a discoloration test in accordance with the following measurement method.

(58) The results are shown in Table 3.

Test Method

(59) The display medium was placed into a gas-barrier transparent container. The container was purged with nitrogen, and subsequently sealed and preserved at a temperature of 25 C. A color change of the discoloration layer was visually observed after a few hours.

(60) After the observation, the display medium was taken out from the container. A color change of the discoloration layer was visually observed after a few hours.

(61) TABLE-US-00003 TABLE 3 Color of discoloration layer After the passage After the Before of a few hours passage of a sealing and after sealing and few hours after preservation preservation unsealing Example 1 blue-violet red blue-violet Example 2 blue-violet red blue-violet Example 3 blue-violet red blue-violet Example 4 blue-violet red blue-violet Example 5 blue-violet red blue-violet Example 6 blue-violet red blue-violet Example 7 blue-violet red blue-violet Example 8 blue-violet red blue-violet Example 9 blue-violet red blue-violet Example 10 blue-violet red blue-violet Example 11 blue-violet red blue-violet Example 12 blue-violet red blue-violet Example 13 blue-violet red blue-violet Example 14 blue-violet red blue-violet Example 15 blue-violet red blue-violet

Results

(62) The color of all of the display mediums thus obtained changed from blue-violet to red after a few hours since they had been sealed and preserved.

(63) When the container was opened, the display mediums were returned to blue-violet after a few hours.

(64) As described above, apparently, the display mediums according to the present invention have an effect of being discolored in an oxygen-present state after unsealing to emphatically display information or the like relating to a commodity formed of the design, symbol or the like even though the discoloration layer thereof are composed of the edible components, which is safe to the human body.

Production Examples 4 to 6

(65) According to the composition of the following Table 4, components were admixed and stirred to obtain oxygen detecting compositions.

(66) TABLE-US-00004 TABLE 4 Composition of oxygen detecting composition (unit: mass %) Ratio Production Production Production Components Example 4 Example 5 Example 6 Methylene blue 0.07 0.10 0.20 Food Red No. 106 0.08 0.10 0.25 Fructose 7.00 5.00 10.00 Sodium hydroxide 1.50 2.00 3.00 Glycerol 5.00 7.00 10.00 Ethanol 40.42 52.00 38.90 Hydroxypropylmethyl 0.60 1.00 1.00 cellulose Vinyl acetate resin 2.00 5.00 10.00 Water 43.33 27.80 26.65 Total 100.00 100.00 100.00

Examples 16 to 24

(67) The display mediums were obtained in the manner as in Example 1 other than being based on the structure shown in following Table 5.

(68) TABLE-US-00005 TABLE 5 Various display mediums Oxygen detecting composition Base material Example 16 Production Example 4 CPP sheet Example 17 Production Example 4 PE sheet Example 18 Production Example 4 Cellophane sheet Example 19 Production Example 5 CPP sheet Example 20 Production Example 5 PE sheet Example 21 Production Example 5 Cellophane sheet Example 22 Production Example 6 CPP sheet Example 23 Production Example 6 PE sheet Example 24 Production Example 6 Cellophane sheet

Test Example 2 Evaluation of Discoloration Property

(69) The display mediums obtained in Examples 16 to 24 above were subjected to a discoloration test in accordance with the manner as in Test Example 1.

(70) The results are shown in Table 6.

(71) TABLE-US-00006 TABLE 6 Color of discoloration layer After the passage After the Before of a few hours passage of a sealing and after sealing and few hours after preservation preservation unsealing Example 16 blue-violet red blue-violet Example 17 blue-violet red blue-violet Example 18 blue-violet red blue-violet Example 19 blue-violet red blue-violet Example 20 blue-violet red blue-violet Example 21 blue-violet red blue-violet Example 22 blue-violet red blue-violet Example 23 blue-violet red blue-violet Example 24 blue-violet red blue-violet

Results

(72) The color of all of the display mediums thus obtained changed from blue-violet to red after a few hours since they had been sealed and preserved.

(73) When the container was opened, the display mediums were returned to blue-violet after a few hours.

(74) As described above, apparently, the display mediums according to the present invention have an effect of being discolored in an oxygen-present state after unsealing to emphatically display information or the like relating to a commodity formed of the design, symbol or the like even though the discoloration layer thereof are composed of the edible components, which is safe to the human body.

Test Example 3 Evaluation of Discoloration Property

(75) The oxygen detecting composition obtained in Production Example 1 above was printed to a paper (manufactured by Fuji Xerox Corporation, V-paper, weight: 64 g/m.sup.2) as character and design to obtain the display medium. The display medium thus obtained was sealed in a gas-barrier packaging body with a deoxidizer. A color change of the discoloration layer was visually observed after a few hours.

(76) After the observation, the display medium was taken out from the packaging body. A color change of the discoloration layer was visually observed after a few hours.

Results

(77) The character and design, which were printed on the surface of the display mediums, changed from blue-violet to red after a few hours since they had been sealed.

(78) When the packaging body was opened, the display mediums were returned to blue-violet after a few hours.

(79) As described above, apparently, the display mediums according to the present invention have an effect that the discoloration layer thereof is discolored when the display mediums are taken out from a sealed gas-barrier packaging body to expose to oxygen, so that information or the like relating to a commodity formed of the design, symbol or the like is emphatically displayed.

INDUSTRIAL APPLICABILITY

(80) The display medium according to the present invention enables to display character, design, symbol, or the like, which shows commodity information such as a commodity name and commodity content(s) so that the character, design, symbol, or the like can be visually strongly recognized by changing color upon transition from a sealed state of being sealed in the container or packaging body in an oxygen-free state to an unsealed state of being exposed in the presence of oxygen.

(81) In addition, since the oxygen detecting composition, which constitutes the discoloration layer of the display medium, is safe to the human body due to comprising edible components only, it can be sealed in the packaging body containing foods, medical supplies or the like at ease.

(82) Thus, the present invention is probably applied to an industry of producing or handling packaging body containing foods, medical supplies or the like.