Temperature-sensitive color-changing ink and time-temperature indicating device

Abstract

The present invention discloses a temperature-sensitive color-changing ink and a time-temperature indicating device. The raw materials for preparing the temperature-sensitive color-changing ink include, by weight, 20 to 35 parts of a binder, 5 to 15 parts of a reducing agent, and 40 to 60 parts of a solvent. The reducing agent can undergo a redox color-changing reaction, and the reaction rate of the redox color-changing reaction is positively correlated with temperature. In the temperature-sensitive color-changing ink, the reducing agent can undergo a redox color-changing reaction, and the rate of the redox color-changing reaction is positively correlated with temperature, i.e., the higher the temperature, the faster the rate of the redox color-changing reaction, and conversely, the lower the temperature, the slower the rate of the redox color-changing reaction. Therefore, the degree of color change can be used to indicate the cumulative amount of heat received, and thus, the time-temperature indicating device can be used to prepare the time-temperature indicating device. The time-temperature indicating device includes a substrate layer, an indicating layer, and an isolation layer, wherein the indicating layer is printed from the temperature-sensitive color-changing ink.

Description

Technical Field

[0001] The present invention relates to the technical field of inks, and in particular to a temperature-sensitive color-changing ink and a time-temperature indicating device. Background Art

[0002] Prior art time-temperature indicating devices typically use phase change materials as indicators, utilizing the penetration length of the phase change materials on microporous materials to indicate the relationship between time and temperature. Since phase change materials have fixed melting and freezing points, they are solid when the temperature is below their freezing points and liquid when the temperature is above their melting points. Therefore, to prevent leakage of the liquid phase change material, special equipment, special materials, and special structures are required to prepare the time-temperature indicating devices. This results in relatively high costs for prior art time-temperature indicating devices, and they have therefore not been widely promoted and applied.

[0003] In redox color-changing reactions, the color-changing agent is usually a reducing agent, and the color changes after the reducing agent is oxidized. This color-changing principle can be used to prepare temperature-sensitive color-changing inks. The ink is solid after drying. Therefore, a low-cost color-changing indicator device can be prepared through conventional structural design.

[0004] However, in reality, people generally have this technical prejudice: the rate of the redox color change reaction is constant, and the only factor affecting the progress of the redox color change reaction is time. Therefore, the redox color change reaction can only be used to prepare timing inks, but not time-temperature indicating inks. For example, the invention patent application with publication number CN104761955A discloses an oxygen-sensitive temperature-sensitive color-changing ink and its preparation method. This temperature-sensitive color-changing ink is a timing ink used to prepare a timing device. The invention patent with publication number CN105928939A discloses an oxygen-sensitive color-changing indicator device. The indicator layer of the color-changing indicator device includes an adsorbent and an indicator composition. The indicator composition can be used to indicate time. Therefore, the color-changing indicator device is essentially a time indicating device.

[0005] Therefore, it is necessary to provide a temperature-sensitive color-changing ink and a time-temperature indicating device based on redox color-changing reaction that can be used to react to the relationship between time and temperature to solve the above problems. Summary of the Invention

[0006] A first aspect of the present invention provides a temperature-sensitive color-changing ink. The raw materials for preparing the temperature-sensitive color-changing ink include, in parts by mass:

[0007] 20 to 35 parts of connecting material;

[0008] 5 to 15 parts of a reducing agent; and

[0009] 40 to 60 parts of solvent;

[0010] The reducing agent can undergo an oxidation-reduction color change reaction, and the reaction rate of the oxidation-reduction color change reaction is positively correlated with the temperature.

[0011] In one embodiment, the reducing agent is a phosphoglyceride.

[0012] In one embodiment, the phosphoglyceride is selected from at least one of natural phospholipids, choline phospholipids, glycerophospholipids, ethanolamine phospholipids, serine phospholipids and phosphatidic acid.

[0013] In one embodiment, the solvent is an organic solvent.

[0014] The temperature-sensitive color-changing ink is characterized in that it further contains 0.01 to 0.5 parts of alkane peroxide or alkoxy free radical.

[0015] In one embodiment, 0.3 to 1 part of an antioxidant is further included.

[0016] In one embodiment, the antioxidant is selected from at least one of tea polyphenols, vitamin E, vitamin E oil, ascorbyl palmitate, propyl gallate, tert-butylhydroquinone, butylated hydroxyanisole, ascorbyl stearate, butylated hydroxyanisole, BHT, 2,6-di-tert-butylated cresol, vitamin C, isoascorbic acid, butylated hydroxytoluene, ursolic acid, sodium D-isoascorbate, soy isoflavones, disodium EDTA, astaxanthin, sodium ascorbate and calcium ascorbate.

[0017] In one embodiment, the composition further comprises 0.05 to 0.5 parts of an ultraviolet absorber.

[0018] In one embodiment, the ultraviolet absorber is selected from any one of salicylate ultraviolet absorbers, benzophenone ultraviolet absorbers, benzotriazole ultraviolet absorbers, substituted acrylonitrile ultraviolet absorbers, triazine ultraviolet absorbers and hindered amine ultraviolet absorbers.

[0019] The above-mentioned temperature-sensitive color-changing ink, the reducing agent can undergo an oxidation-reduction color-changing reaction, and the rate of the oxidation-reduction color-changing reaction is positively correlated with the temperature, that is, the higher the temperature, the faster the rate of the oxidation-reduction color-changing reaction, and conversely, the lower the temperature, the slower the rate of the oxidation-reduction color-changing reaction. Therefore, the degree of color change can be used to indicate the cumulative amount of heat received, and therefore, it can be used to prepare a time-temperature indicating device.

[0020] A second aspect of the present invention provides a time-temperature indicating device, comprising:

[0021] a substrate layer made of a dense material;

[0022] a substrate layer made of a dense material;

[0023] an indicator layer, laminated on the substrate layer, the indicator layer being obtained by printing with any one of the temperature-sensitive color-changing inks described above;

[0024] The isolation layer is stacked on a side of the indicator layer away from the substrate layer, and the isolation layer is made of a dense material.

[0025] The above-mentioned time-temperature indicating device has a simple structure. The indicating layer is obtained by printing the temperature-sensitive color-changing ink of the first aspect of the present invention. The reducing agent of the temperature-sensitive color-changing ink can undergo an oxidation-reduction color-changing reaction, and the rate of the oxidation-reduction color-changing reaction is positively correlated with the temperature, that is, the higher the temperature, the faster the rate of the oxidation-reduction color-changing reaction, and conversely, the lower the temperature, the slower the rate of the oxidation-reduction color-changing reaction. Therefore, the degree of color change can be used to indicate the cumulative amount of heat received. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 This is a schematic structural diagram of a time-temperature indicating device according to one embodiment;

[0027] Figure 2 This is a schematic structural diagram of a time-temperature indicating device according to another embodiment. DETAILED DESCRIPTION

[0028] To make the above-mentioned objects, features, and advantages of the present invention more readily apparent, specific embodiments of the present invention are described in detail below with reference to the accompanying drawings. The following description sets forth numerous specific details to facilitate a full understanding of the present invention. However, the present invention can be implemented in many other ways than those described herein, and those skilled in the art may make similar modifications without departing from the scope of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0029] It should be noted that when an element is referred to as being "fixed to" another element, it may be directly on the other element or there may be an intermediate element. When an element is considered to be "connected" or "communicating" with another element, it may be directly connected to the other element or there may be an intermediate element. The terms "upper," "lower," "vertical," "horizontal," "left," "right," and similar expressions used herein are for illustrative purposes only and do not represent the only implementation methods.

[0030] The temperature-sensitive color-changing ink and the time-temperature indicating device will be further described in detail below mainly with reference to the accompanying drawings and specific embodiments.

[0031] The temperature-sensitive color-changing ink of one embodiment comprises, by weight, 20 to 35 parts of a binder, 5 to 15 parts of a reducing agent, and 40 to 60 parts of a solvent.

[0032] The binder has a mass content of 20 to 35 parts by mass. The binder can be dissolved in a solvent and is used to allow the temperature-sensitive color-changing ink to dry into a film after printing.

[0033] Optionally, the connecting material is selected from at least one of acrylic resin, polyurethane epoxy resin, polyketone resin and polyamide resin.

[0034] The reducing agent has a mass fraction of 5 to 15 parts. The reducing agent can undergo a redox color change reaction with oxygen in the air, and the rate of the redox color change reaction is positively correlated with the temperature, that is, the higher the temperature, the faster the rate of the redox color change reaction, and the lower the temperature, the lower the rate of the redox color change reaction.

[0035] In this embodiment, the reducing agent is phosphoglyceride, also known as phospholipid. Phosphoglyceride containing a small amount of impurities is light yellow in color, and when its purity reaches 98% or greater, the color of the phosphoglyceride is white. Furthermore, the physical form of the phosphoglyceride is related to its preparation process. Phosphoglyceride prepared using a freeze-drying process is in a paste-like form, while phosphoglyceride prepared using a spray-drying process is in a powdery form.

[0036] From the molecular structure, the main chain of phosphoglyceride is glycerol-3-phosphate, in which the hydroxyl groups on glycerol C1 and C2 are esterified with fatty acids to form two long fatty acid chains, and the hydroxyl group on glycerol C3 is esterified with phosphate, and the phosphoric acid is connected to a polar alcohol (X-OH).

[0037] Specifically, C1 on the glycerol carbon skeleton is connected to a saturated fatty acid containing 16 or 18 carbon atoms through an ester bond, and C2 is connected to an unsaturated fatty acid containing 16 to 20 carbon atoms through an ester bond. On the one hand, this allows oxygen to undergo a redox color change reaction with the unsaturated fatty acid on C2. During the oxidation process, the double bond of the fatty acid is oxidized and broken, generating a large number of alkane peroxides (ROO-) and alkoxy free radicals (RO-). The final product of oxidation will increase the free fatty acid content in the phosphoglyceride and increase the acid value. In this process, the phosphoglyceride gradually changes from the initial light yellow to brown-black, thus having a color change characteristic. On the other hand, different fatty acids are connected to C1 and C2, so that the phosphoglyceride has different phase transition temperatures. Although the final physical form of the phosphoglyceride can be changed through the preparation process, it is surprising that regardless of whether the physical form of the phosphoglyceride changes, its redox color change reaction has the following relationship:

[0038] (1) For the same phosphoglyceride, the higher the temperature, the faster the rate of its redox color change reaction. Conversely, the lower the temperature, the lower the rate of its redox color change reaction. That is, the redox color change reaction rate of phosphoglyceride is temperature-sensitive.

[0039] (2) For two phosphoglycerides with different phase transition temperatures, under the same temperature conditions, the phosphoglyceride with a lower phase transition temperature has a faster redox color change reaction rate, while the phosphoglyceride with a higher phase transition temperature has a slower redox color change reaction rate.

[0040] Therefore, the thermal characteristics of the temperature-sensitive color-changing ink can be adjusted by adjusting the type of phosphoglyceride.

[0041] Optionally, the phosphoglyceride includes but is not limited to at least one of natural phospholipids, choline phospholipids PC, glycerophospholipids PG, ethanolamine phospholipids PE, serine phospholipids PS and phosphatidic acid PA. Table 1 lists the phase transition temperatures of some different phosphoglycerides.

[0042] Table 1 Phase transition temperature of different phosphoglycerides

[0043]

[0044]

[0045] The solvent, calculated by weight, is in the range of 40 to 60 parts by weight and is used to dissolve the binder so that the ink meets the requirements of printability.

[0046] In this embodiment, the solvent is an organic solvent. Since water molecules can promote the deterioration of phosphoglyceride, using an organic solvent as the solvent of the present invention can improve the chemical stability of the temperature-sensitive color-changing ink before printing.

[0047] Preferably, the solvent is a non-polar organic solvent. Since phosphoglyceride is an amphiphilic molecule with a hydrophilic nitrogen- or phosphorus-containing head at one end and a long hydrophobic hydrocarbon chain at the other, it is readily soluble in non-polar organic solvents. Upon dissolution, the hydrophilic and hydrophobic ends of the phosphoglyceride molecules approach each other, forming spherical reverse micelles with the hydrophobic groups facing outward and the hydrophilic groups facing inward. After the thermochromic ink dries, the phosphoglyceride molecules retain the spherical reverse micelle shape. At this point, the outward-facing hydrophobic groups contain unsaturated double bonds, allowing them to come into contact with oxygen, facilitating the redox color change reaction. Furthermore, the inward-facing hydrophilic groups present a hydrophobic nature, preventing the thermochromic ink from absorbing moisture and deteriorating, thereby improving its water resistance.

[0048] Optionally, the organic solvent includes but is not limited to: ether, benzene, chloroform and n-hexane.

[0049] In another embodiment, the temperature-sensitive color-changing ink further includes 0.01 to 0.5 parts of an alkane peroxide (ROO-) or an alkoxy free radical (RO-). The alkane peroxide (ROO-) is the same as the alkane peroxide (ROO-) obtained by oxidizing phosphoglyceride, and the alkoxy free radical (RO-) is the same as the alkoxy free radical (RO-) obtained by oxidizing phosphoglyceride. Because phosphoglyceride generates a large amount of alkane peroxide (ROO-) and alkoxy free radical (RO-) during the redox color-changing reaction, experiments have found that adding a certain amount of alkane peroxide (ROO-) or alkoxy free radical (RO-) to the temperature-sensitive color-changing ink can inhibit the rate of the redox color-changing reaction of phosphoglyceride, thereby adjusting the heat sensitivity of the temperature-sensitive color-changing ink.

[0050] In another embodiment, the temperature-sensitive color-changing ink further includes 0.3 to 1 parts of an antioxidant, by weight. By adding the antioxidant, on the one hand, the chemical stability of the temperature-sensitive color-changing ink before printing can be improved, and on the other hand, the color change rate of the temperature-sensitive color-changing ink can be slowed down, thereby adjusting the thermal sensitivity of the temperature-sensitive color-changing ink.

[0051] Optionally, antioxidants include but are not limited to: tea polyphenols, vitamin E, vitamin E oil, ascorbyl palmitate, propyl gallate, tert-butylhydroquinone, butylated hydroxyanisole, ascorbyl stearate, butylated hydroxyanisole, BHT, 2,6-di-tert-butylated cresol, vitamin C, isoascorbic acid, butylated hydroxytoluene, ursolic acid, sodium D-isoascorbate, soy isoflavones, disodium EDTA, astaxanthin, sodium ascorbate and calcium ascorbate.

[0052] In another embodiment, the temperature-sensitive color-changing ink further includes 0.05 to 0.5 parts of ultraviolet absorber. By adding the ultraviolet absorber, the light resistance of the temperature-sensitive color-changing ink can be improved, thereby helping to improve the use requirements of the temperature-sensitive color-changing ink in different lighting environments.

[0053] Optionally, the ultraviolet absorber includes, but is not limited to, salicylate ultraviolet absorbers, benzophenone ultraviolet absorbers, benzotriazole ultraviolet absorbers, substituted acrylonitrile ultraviolet absorbers, triazine ultraviolet absorbers and hindered amine ultraviolet absorbers.

[0054] In the above-mentioned temperature-sensitive color-changing ink, the reducing agent can undergo an oxidation-reduction color-changing reaction with oxygen, and the rate of the oxidation-reduction color-changing reaction is positively correlated with the temperature, that is, the higher the temperature, the faster the rate of the oxidation-reduction color-changing reaction, and conversely, the lower the temperature, the slower the rate of the oxidation-reduction color-changing reaction. Therefore, the degree of color change can be used to indicate the cumulative amount of heat received, and therefore, it can be used to prepare a time-temperature indicating device.

[0055] One embodiment of the time temperature indicating device, please refer to Figure 1 , including a base layer 10, an indicator layer 20 and an isolation layer 30 which are stacked.

[0056] The substrate layer 10 is used to support the indicator layer 20 . The substrate layer 10 is made of a dense material and can prevent air and water molecules from passing through.

[0057] Optionally, the materials used to prepare the substrate layer 10 include, but are not limited to: aluminum foil, PET film, PVC film and aluminum-plastic composite material.

[0058] The indicator layer 20 is laminated on the substrate layer 10 and includes a color-changing region 21 . The color-changing region 21 is obtained by printing and drying any one of the above-mentioned temperature-sensitive color-changing inks.

[0059] In another embodiment, see Figure 2 A reference area 22 is also provided at the edge of the color-changing area 21. This area is printed with standard ink and includes a starting color, an intermediate color, and an end color. These colors represent the starting, intermediate, and end colors of the color-changing area 21, respectively. Therefore, by comparing the color-changing area 21 with the reference area 22, the user can intuitively determine the cumulative heating level of the temperature indicator at the current time.

[0060] The isolation layer 30 is laminated and removably disposed on the side of the indicator layer 20 away from the substrate layer 10. The isolation layer 30 is made of a dense material and is used to prevent air and water molecules from contacting the color-changing area 21. When in use, the time and temperature indicator device can be activated by removing the isolation layer 30.

[0061] Optionally, the materials used to prepare the isolation layer 30 include, but are not limited to: aluminum foil, PET film, PVC film and aluminum-plastic composite material.

[0062] The above-mentioned time-temperature indicating device has a simple structure. The indicating layer 20 is printed by the temperature-sensitive color-changing ink of the first aspect of the present invention. The reducing agent of the temperature-sensitive color-changing ink can undergo an oxidation-reduction color-changing reaction with oxygen, and the rate of the oxidation-reduction color-changing reaction is positively correlated with the temperature, that is, the higher the temperature, the faster the rate of the oxidation-reduction color-changing reaction, and conversely, the lower the temperature, the slower the rate of the oxidation-reduction color-changing reaction. Therefore, the degree of color change can be used to indicate the cumulative amount of heat received.

[0063] The following are specific examples.

[0064] Example 1

[0065] This embodiment provides a temperature-sensitive color-changing ink, including: 20 parts of a binder, 5 parts of a reducing agent, and 40 parts of a solvent. In this embodiment, the binder is an acrylic resin, the reducing agent is dilauroylphosphatidylglycerol (sodium salt) DLPG-Na, provided by Xi'an Ruixi Biotechnology Co., Ltd., its phase change temperature is -3 degrees, and the solvent is n-hexane.

[0066] In the above-mentioned temperature-sensitive color-changing ink, the reducing agent can undergo an oxidation-reduction color-changing reaction with oxygen, and the rate of the oxidation-reduction color-changing reaction is positively correlated with the temperature, that is, the higher the temperature, the faster the rate of the oxidation-reduction color-changing reaction, and conversely, the lower the temperature, the slower the rate of the oxidation-reduction color-changing reaction. Therefore, the degree of color change can be used to indicate the cumulative amount of heat received, and therefore, it can be used to prepare a time-temperature indicating device.

[0067] See also Figure 1 This embodiment also provides a time-temperature indicating device, which includes a stacked substrate layer 10, an indicating layer 20, and an isolation layer 30, wherein the substrate layer 10 is a PET film, the indicating layer 20 includes a color-changing area 21, and the color-changing area 21 is obtained by printing and drying the temperature-sensitive color-changing ink provided in this embodiment, and the isolation layer 30 is a PET film.

[0068] The above-mentioned time-temperature indicator has a simple structure. The indicator layer 20 is printed with the temperature-sensitive color-changing ink of the first aspect of the present invention. The reducing agent in this temperature-sensitive color-changing ink undergoes a redox color-changing reaction with oxygen. The rate of this redox color-changing reaction is positively correlated with temperature. That is, the higher the temperature, the faster the redox color-changing reaction, while the lower the temperature, the slower the redox color-changing reaction. Therefore, the degree of color change can be used to indicate the cumulative amount of heat received. After activation, the time-temperature indicator changes color every 10 days at 5°C and every 6 days at 15°C.

[0069] Example 2

[0070] The temperature-sensitive color-changing ink provided in this embodiment is similar to the temperature-sensitive color-changing ink provided in Example 1, except that: (1) the binder is a polyurethane epoxy resin, the weight fraction of which is 27 parts; (2) the reducing agent is dimyristoylphosphatidylcholine DMPC, the weight fraction of which is 10 parts, the phase transition temperature of which is 23 degrees, and which is provided by Hefei Kemik Biochemical Technology Co., Ltd.; (3) the solvent is a mixture of chloroform and n-hexane in a ratio of 1:1, the weight fraction of which is 50 parts.

[0071] See also Figure 2This embodiment also provides a time-temperature indicating device, which is similar to the time-temperature indicating device provided in Example 1, except that: (1) the indicating layer 20 also includes a reference area 22, and the reference area 22 is printed with ordinary ink; (2) the color-changing area 21 is printed and dried with the temperature-sensitive color-changing ink provided in this embodiment.

[0072] The above-mentioned time-temperature indicating device has a color change period of 20 days in an environment of 5°C and a color change period of 12 days in an environment of 15°C.

[0073] Example 3

[0074] The temperature-sensitive color-changing ink provided in this embodiment is similar to the temperature-sensitive color-changing ink provided in Example 2, except that: (1) the binder is a polyamide resin, the weight fraction of which is 35 parts; (2) the reducing agent is dipalmitoyl phospholipid DPPE, provided by Xi'an Ruixi Biotechnology Co., Ltd., the weight fraction of which is 15 parts, and the phase transition temperature of which is 63 degrees; (3) the solvent is chloroform, the weight fraction of which is 60 parts.

[0075] This embodiment also provides a time-temperature indicating device, which is similar to the time-temperature indicating device provided in Example 2, except that: (1) the color-changing area 21 is obtained by printing and drying the temperature-sensitive color-changing ink provided in this embodiment.

[0076] The above-mentioned time-temperature indicating device has a color change period of 40 days in an environment of 5°C and a color change period of 20 days in an environment of 15°C.

[0077] Example 4

[0078] The temperature-sensitive color-changing ink provided in this embodiment is similar to the temperature-sensitive color-changing ink provided in Example 3, except that it also includes 7 parts of an antioxidant. In this embodiment, the antioxidant is sodium ascorbate, which is provided by Suzhou Baiyixin Biotechnology Co., Ltd.

[0079] This embodiment also provides a time-temperature indicating device, which is similar to the time-temperature indicating device provided in Example 3, except that: (1) the color-changing area 21 is obtained by printing and drying the temperature-sensitive color-changing ink provided in this embodiment.

[0080] The above-mentioned time-temperature indicating device has a color change period of 50 days in an environment of 5°C and a color change period of 25 days in an environment of 15°C.

[0081] The above-described embodiments merely illustrate several implementations of the present invention, and while their descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the patent. It should be noted that a person skilled in the art would be able to make numerous variations and improvements without departing from the spirit of the present invention, all of which fall within the scope of protection of the present invention. Therefore, the scope of protection of the patent for this invention shall be determined by the appended claims.

Claims

1. A temperature-sensitive color-changing ink, characterized in that: The raw materials for preparing the temperature-sensitive color-changing ink include, by parts by mass: 20~35 parts of connecting material; 0.01 to 0.5 parts of alkane peroxide or alkoxy free radical; 0.3 to 1 part antioxidant; 5 to 15 parts of a reducing agent; and 40 to 60 parts of solvent; The binder is selected from at least one of acrylic resin, polyurethane epoxy resin, polyketone resin and polyamide resin; the solvent is selected from at least one of ether, benzene, chloroform and n-hexane; the reducing agent is phosphoglyceride; the alkane peroxide is the same as the alkane peroxide obtained after oxidation of the phosphoglyceride; the alkoxy free radical is the same as the alkoxy free radical obtained after oxidation of the phosphoglyceride; the reducing agent can undergo a redox color change reaction; and the reaction rate of the redox color change reaction is positively correlated with the temperature.

2. The temperature-sensitive color-changing ink according to claim 1, characterized in that: The phosphoglyceride is selected from at least one of choline phospholipids, glycerophospholipids, ethanolamine phospholipids, serine phospholipids and phosphatidic acid.

3. The temperature-sensitive color-changing ink according to claim 2, characterized in that: The antioxidant is selected from at least one of tea polyphenols, vitamin E, ascorbyl palmitate, propyl gallate, tert-butylhydroquinone, butylated hydroxyanisole, ascorbyl stearate, butylated hydroxyanisole, 2,6-di-tert-butylated cresol, vitamin C, isoascorbic acid, butylated hydroxytoluene, ursolic acid, sodium D-isoascorbate, soy isoflavones, disodium EDTA, astaxanthin, sodium ascorbate and calcium ascorbate.

4. The temperature-sensitive color-changing ink according to claim 1, characterized in that: Calculated by weight, the composition further includes 0.05 to 0.5 parts of ultraviolet absorber.

5. The temperature-sensitive color-changing ink according to claim 4, characterized in that: The ultraviolet absorber is selected from any one of salicylate ultraviolet absorbers, benzophenone ultraviolet absorbers, benzotriazole ultraviolet absorbers, substituted acrylonitrile ultraviolet absorbers, triazine ultraviolet absorbers and hindered amine ultraviolet absorbers.

6. A time-temperature device, characterized in that: include: a substrate layer made of a dense material; an indicator layer, laminated on the substrate layer, the indicator layer being obtained by printing the temperature-sensitive color-changing ink according to any one of claims 1 to 5; The isolation layer is stacked on a side of the indicator layer away from the substrate layer, and the isolation layer is made of a dense material.

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