Indicating ink and application thereof

Abstract

The invention relates to indicating ink and application thereof, and belongs to the technical field of indicating ink. The invention provides indicating ink which comprises the following components in parts by weight: 0.5-15 parts of a metal oxide catalyst, 40-80 parts of ionic liquid, 0.1-3 parts of a viscosity modifier and 1-10 parts of a microcapsule encapsulating agent, the microcapsule packaging agent comprises a polymer shell and a sterilizing color-changing color developing agent encapsulated in the polymer shell. The indicating ink disclosed by the invention can generate obvious color change in the H2O2 plasma sterilization process so as to monitor whether the sterilization process meets the requirements or not. The indication ink can be used for instantly manufacturing a sterilization indication card in an ink-jet printing mode, the inventory management problem of a traditional printing indication card is avoided, and the flexibility and accuracy of sterilization monitoring are improved. The system is suitable for hospitals, medical instrument sterilization centers and other scenes where the H2O2 sterilization effect needs to be accurately monitored.

Description

Technical Field

[0001] The invention belongs to the technical field of indicator inks, and in particular relates to an indicator ink and application thereof. Background Art

[0002] Existing sterilization indicator cards typically utilize screen printing or flexographic printing, pre-printing sterilization color-changing indicator ink onto the card. While a proven method, this approach suffers from long production cycles, complex inventory management, and limited flexibility, making it difficult to meet the needs of small batches and personalized needs. Furthermore, some traditional indicator inks exhibit defects such as uneven color change and poor storage stability, compromising the accuracy of sterilization monitoring.

[0003] Inkjet printing technology has gained popularity in many industrial and medical applications due to its high precision, flexibility, and instant printing capabilities. However, due to limitations such as the high volatility of conventional ink solvents, ink viscosity, and the dispersibility of colorants, there are currently no inkjet-printable color-changing indicator inks suitable for use in H2O2 plasma sterilization environments. Therefore, developing a sterilization color-changing indicator ink suitable for inkjet printing, enabling instant printing of sterilization monitoring cards, would be of great value. Summary of the Invention

[0004] The purpose of the present invention is to overcome the problems existing in the above-mentioned prior art and provide an indicator ink and its application.

[0005] The present invention is achieved through the following technical solutions:

[0006] In a first aspect, the present invention provides an indicator ink comprising the following components, measured by weight: 0.5 to 15 parts of a metal oxide catalyst, 40 to 80 parts of an ionic liquid, 0.1 to 3 parts of a viscosity regulator, and 1 to 10 parts of a microcapsule encapsulator; the microcapsule encapsulator comprises a polymer shell and a sterilization color-changing developer encapsulated inside the polymer shell.

[0007] The indicator ink of the present invention can undergo significant color changes during the H2O2 plasma sterilization process to monitor whether the sterilization process meets the requirements. The ink of the present invention uses nano-metal oxides as catalysts to increase the reactivity of H2O2 and enhance the sensitivity of color changes; selects ionic liquids as non-volatile solvents to improve the storage stability of the ink; and simultaneously uses microcapsules to encapsulate the sterilization color-changing developer inside the microcapsules, thereby enhancing the H2O2 penetration rate and making the color change faster and more adjustable. The indicator ink can be used to instantly produce sterilization indicator cards through inkjet printing, avoiding the inventory management difficulties of traditional printed indicator cards and improving the flexibility and accuracy of sterilization monitoring. The present invention is suitable for hospitals, medical device sterilization centers, and other scenarios where the H2O2 sterilization effect needs to be accurately monitored.

[0008] Preferably, the metal oxide catalyst includes at least one of Fe2O3, ZnO, TiO2, and CeO2.

[0009] More preferably, the metal oxide catalyst includes at least one of TiO2 and CeO2.

[0010] Furthermore, the metal oxide catalyst includes TiO2 and CeO2.

[0011] The present invention uses nano-metal oxides as catalysts to improve catalytic activity and enhance the sensitivity of the color change reaction. The main function of nano-metal oxides TiO2 and CeO2 as catalysts is to accelerate the decomposition reaction of H2O2, causing it to produce hydroxyl radicals (·OH) with strong oxidizing properties more quickly. These free radicals can undergo redox reactions with the color developer molecules, changing their electronic structure and thus causing color changes. TiO2 has good photocatalytic properties and can catalyze H2O2 to generate more reactive oxygen species (ROS) under appropriate oxidizing conditions, further improving the sensitivity of the color development reaction. CeO2, due to its reversible CeO2 3+ / Ce 4+ The conversion characteristics of nanoparticles enhance the redox cycle under the action of H2O2, improving catalytic efficiency and stabilizing the reaction rate. Furthermore, the large specific surface area of ​​nanoparticles increases the number of active sites for the catalytic reaction, increasing the degradation rate of H2O2 and, in turn, accelerating the color change response time of the developer. Compared to catalysts such as Fe2O3 and ZnO, the composite catalysis of nano-TiO2 and CeO2 can further increase the H2O2 reaction rate, making the color change reaction faster and more controllable.

[0012] Preferably, the sterilization color-changing color developer includes at least one of rhodamine B, bromophenol green, bromophenol blue, neutral red, methyl violet or methylene blue.

[0013] Preferably, the amount of the sterilization color-changing developer in the indicator ink is 0.1 to 5 parts by weight.

[0014] Preferably, the ionic liquid includes at least one of 1-ethyl-3-methylimidazolium tetrafluoroborate, 1-butyl-3-methylimidazolium hexafluorophosphate (BMIMPF6), and 1-ethyl-3-methylimidazolium methanesulfonate.

[0015] More preferably, the ionic liquid is 1-ethyl-3-methylimidazolium tetrafluoroborate.

[0016] The addition of ionic liquids to the indicator ink of the present invention can improve the storage stability of the ink. The ionic liquid has an extremely low vapor pressure, which can effectively prevent the solvent from volatilizing and avoid concentration changes or crystallization of the ink during long-term storage, thereby maintaining a uniform formula. By providing a stable polar environment, the developer and catalyst are evenly dispersed, preventing color failure due to precipitation or decomposition. In addition, the ionic liquid has a high viscosity, which can reduce the diffusion of the ink during the inkjet printing process, ensure that the printed pattern is clear, and maintain consistent fluidity during storage. Compared with other ionic liquids, the tetrafluoroborate (BF4 - ) can effectively isolate the unexpected oxidation effect of the oxidant on the color developer, thereby reducing the background color change, improving the controllability of the color development reaction, and having better performance.

[0017] Preferably, the viscosity modifier comprises at least one of ethylene glycol, glycerol or propylene glycol.

[0018] Preferably, the polymer shell comprises at least one of silicone polymer, polyurea, and polymethacrylate.

[0019] More preferably, said polymer shell is a silicone polymer.

[0020] The present invention adds a microcapsule encapsulant to increase the permeation rate of H2O2 and make the color development reaction faster and more adjustable. Furthermore, the present invention uses a silicone polymer as the shell of the microcapsule encapsulant, which can form a porous structure, making it easier for H2O2 molecules to penetrate into the internal color developer area, thereby increasing the reaction rate. By regulating the cross-linking density of the silicone and the thickness of the microcapsule shell, the permeation rate of H2O2 can be precisely adjusted. For example, silicone polymer microcapsules with low cross-linking density provide a faster permeation rate, allowing color changes to be completed within a few seconds; while silicone polymer microcapsules with high cross-linking density can be used to delay the reaction, allowing the color change to occur after several minutes or longer, which is suitable for different sterilization monitoring needs. In addition, silicone has strong chemical stability and is not easily degraded. It can ensure the stability of the indicator ink during storage and prevent the color developer from prematurely changing color when it is not in contact with H2O2.

[0021] Preferably, the preparation method of the microcapsule encapsulation agent with a silicone polymer as the polymer shell comprises the following steps: reacting methyltriethoxysilane (MTES) and tetraethyl orthosilicate (TEOS) under the catalytic action of a base, adding the sterilization color-changing developer, continuing the reaction, and drying to obtain the microcapsule encapsulation agent with a silicone polymer as the polymer shell.

[0022] The microcapsule encapsulant with a siloxane polymer as the polymer shell is prepared by a sol-gel method. Methyltriethoxysilane serves as a silicon source to provide a hydrophobic skeleton, and ethyl orthosilicate can structurally regulate the silicon source to form a cross-linked network to obtain a porous microcapsule shell structure, which can embed a color developer and regulate its penetration and release rate of H2O2.

[0023] Preferably, the molar ratio of methyltriethoxysilane (MTES) to tetraethyl orthosilicate (TEOS) is (1-5):1.

[0024] Preferably, the base comprises aqueous ammonia.

[0025] Preferably, the reaction temperature is 35° C.-45° C., and the reaction time is 1.5 h-2.5 h; and the continued reaction time is 0.5 h-1.5 h.

[0026] In a second aspect, the present invention provides use of the indicator ink in peroxide plasma sterilization indicator products.

[0027] Specifically, the indicator supplies include but are not limited to indicator cards, indicator labels or indicator tapes.

[0028] In a third aspect, the present invention provides a sterilization indicator card, comprising a substrate and the indicator ink of the present invention inkjet-printed on the substrate.

[0029] Preferably, the method for preparing the sterilization indicator card comprises the following steps: loading the indicator ink of the present invention into an ink cartridge of an inkjet printing device, selecting a sterilization indicator label template on a computer or printing device, and using the inkjet printing device to instantly print the desired sterilization indicator label on the substrate, thereby obtaining the sterilization indicator card.

[0030] In practical applications, the sterilization indicator card obtained by the present invention is placed in a H2O2 plasma sterilization device for sterilization, and the color change of the indicator card is observed to determine whether the sterilization has achieved the expected effect.

[0031] Specifically, the indicator mark template includes but is not limited to a standard barcode, a text mark, and a pattern; the substrate includes but is not limited to absorbent paper, PET film, or coated paper.

[0032] The present invention has the following beneficial effects: the indicator ink utilizes a nanocatalyst to increase the color change reaction rate and color contrast, resulting in high sensitivity. The use of an ionic liquid reduces solvent volatilization, improving the ink's storage stability and lifespan. The microencapsulation enhances the permeation rate of hydrogen peroxide, resulting in rapid color change. Furthermore, the indicator ink is suitable for use with inkjet printing equipment, enabling personalized, on-demand production. The color contrast before and after sterilization is high, improving identification accuracy. The ink is also suitable for use on a variety of printing media, including coated paper, synthetic paper, and PET film, meeting the production requirements of various sterilization indicator cards. DETAILED DESCRIPTION

[0033] To better illustrate the purpose, technical solutions and advantages of the present invention, the present invention will be further described below in conjunction with specific embodiments. Those skilled in the art should understand that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0034] Unless otherwise specified, the experimental methods used in the examples are conventional methods; the materials, reagents, etc. used are all available from commercial sources unless otherwise specified.

[0035] Example 1

[0036] An indicator ink comprises the following components, measured by weight: 5 parts of nano-TiO2, 3 parts of nano-CeO2, 60 parts of 1-ethyl-3-methylimidazolium tetrafluoroborate, 2 parts of ethylene glycol, and 5 parts of silicone microcapsules; the silicone microcapsules have a silicone polymer as a polymer shell and are coated with bromophenol green, wherein the weight portion of bromophenol green is 1 part; the components are uniformly mixed to obtain the indicator ink.

[0037] The preparation method of the silicone microcapsules comprises the following steps: mixing MTES and TEOS in a molar ratio of 3:1, stirring evenly, adding ammonia water as a catalyst, controlling the pH value to be ≈10, reacting at 40° C. for 2 hours, adding a color developer, continuing stirring for 1 hour, and drying at low temperature to obtain the silicone microcapsules.

[0038] Example 2

[0039] An indicator ink comprising the following components, measured by weight: 6 parts of nano-CeO2, 55 parts of 1-ethyl-3-methylimidazolium tetrafluoroborate, 3 parts of glycerol, and 7 parts of silicone microcapsules; the silicone microcapsules have a silicone polymer as a polymer shell and are coated with color developers Rhodamine B and bromophenol blue, with the weight of Rhodamine B being 1 part and the weight of bromophenol blue being 1 part.

[0040] The preparation method of the silicone microcapsules is the same as that in Example 1.

[0041] Example 3

[0042] An indicator ink comprising the following components, measured by weight: 4 parts of nano-TiO2, 70 parts of 1-ethyl-3-methylimidazolium tetrafluoroborate, 2 parts of ethylene glycol, and 6 parts of silicone microcapsules; the silicone microcapsules have a silicone polymer as a polymer shell and are coated with a color developer, methylene blue, with the weight portion of methylene blue being 2 parts;

[0043] The preparation method of the silicone microcapsules is the same as that in Example 1.

[0044] Example 4

[0045] The difference between the indicator ink of this embodiment and that of embodiment 1 is that the indicator ink of this embodiment does not contain nano-TiO2 and nano-CeO2, but adds 8 parts of Fe2O3. The other component parameters are the same as those of embodiment 1.

[0046] Example 5

[0047] The difference between the indicator ink of this embodiment and that of embodiment 2 is that the indicator ink does not contain nano-TiO2 and nano-CeO2, but 8 parts of ZnO are added. The other component parameters are the same as those of embodiment 2.

[0048] Example 6

[0049] The indicator ink of this embodiment differs from that of embodiment 3 in that it does not contain nano-TiO2 and nano-CeO2, but adds 8 parts of Fe2O3. Other component parameters are the same as those of embodiment 3.

[0050] Example 7

[0051] The indicator ink of this embodiment differs from that of Example 1 in that it does not contain nano-TiO 2 and nano-CeO 2 , but contains 8 parts of ZnO. Other component parameters are the same as those of Example 1.

[0052] Example 8

[0053] The difference between the indicator ink of this embodiment and that of embodiment 1 is that the indicator ink does not contain nano-CeO2, the amount of nano-TiO2 is 8 parts, and the other component parameters are the same as those of embodiment 1.

[0054] Example 9

[0055] The difference between the indicator ink of this embodiment and that of embodiment 1 is that the indicator ink does not contain nano-TiO2, the amount of nano-CeO2 is 8 parts, and the other component parameters are the same as those of embodiment 1.

[0056] Example 10

[0057] The indicator ink of this embodiment differs from that of Example 1 in that 1-ethyl-3-methylimidazolium tetrafluoroborate is not contained, and 60 parts of 1-butyl-3-methylimidazolium hexafluorophosphate are added. Other component parameters are the same as those of Example 1.

[0058] Example 11

[0059] The indicator ink of this embodiment differs from that of Example 1 in that 1-ethyl-3-methylimidazolium tetrafluoroborate is not contained, and 60 parts of 1-ethyl-3-methylimidazolium methanesulfonate are added. Other component parameters are the same as those of Example 1.

[0060] Example 12

[0061] The difference between the indicator ink of this embodiment and that of embodiment 1 is that the indicator ink of this embodiment does not contain siloxane microcapsules, but contains 5 parts of polyurea microcapsules. The polyurea microcapsules have polyurea as a polymer shell and are coated with a color developer, Rhodamine B, with a weight portion of Rhodamine B of 0.5 parts.

[0062] The preparation method of the polyurea microcapsules comprises the following steps: dissolving 1.5 g of isophorone diisocyanate (IPDI) and 0.05 g of rhodamine B in 10 mL of dichloromethane and stirring to form an oil phase; emulsifying the oil phase at high speed (8000 rpm) for 5 minutes in 100 mL of deionized water containing 2 wt% polyvinyl alcohol to form a stable O / W emulsion; then slowly adding 1.0 g of an aqueous solution of ethylenediamine dropwise; controlling the reaction temperature at 35° C. and reacting under magnetic stirring for 2 hours to form a polyurea microcapsule shell at the interface; aging the mixture for 1 hour after completion of the reaction, washing it three times with distilled water, and vacuum drying it to obtain a polyurea microcapsule powder containing a color developer. All other component parameters are the same as those in Example 1.

[0063] Example 13

[0064] The difference between the indicator ink of this embodiment and that of embodiment 1 is that the indicator ink of this embodiment does not contain silicone microcapsules, but contains 5 parts of polymethacrylate microcapsules. The polymethacrylate microcapsules have a polymer shell of polymethacrylate and are coated with a color developer bromophenol blue. The weight portion of bromophenol blue is 1 part.

[0065] The preparation method of the polymethacrylate microcapsules comprises the following steps: dissolving 1.0 g of bromophenol blue developer and 2.0 g of methyl methacrylate (MMA) monomer in 10 mL of butyl acetate, adding 0.05 g of initiator benzoyl peroxide (BPO) and mixing uniformly to form an oil phase, slowly adding the oil phase to 100 mL of deionized water containing 2 wt% polyvinyl alcohol (PVA), and using high-speed shear emulsification (7000 rpm) to form a stable emulsion; then transferring the emulsion to an 80°C water bath for insulated polymerization for 4 hours. After the reaction is completed, the emulsion is cooled to room temperature, repeatedly washed with distilled water, filtered, and dried at low temperature to obtain polymethacrylate microcapsules encapsulating the developer. Other component parameters are the same as those in Example 1.

[0066] Comparative Example 1

[0067] The difference between the indicator ink of this comparative example and Example 1 is that 1-ethyl-3-methylimidazolium tetrafluoroborate is not contained, and other component parameters are the same as those of Example 1.

[0068] Comparative Example 2

[0069] The difference between the indicator ink of this comparative example and Example 1 is that the indicator ink does not contain silicone microcapsules, that is, the color developer is not encapsulated inside the silicone microcapsules. Other component parameters are the same as those of Example 1.

[0070] Comparative Example 3

[0071] The difference between the indicator ink of this comparative example and Example 2 is that 1-ethyl-3-methylimidazolium tetrafluoroborate is not contained, and other component parameters are the same as those of Example 2.

[0072] Comparative Example 4

[0073] The difference between the indicator ink of this comparative example and Example 2 is that the indicator ink does not contain silicone microcapsules, that is, the developer is not encapsulated inside the silicone microcapsules. Other component parameters are the same as those of Example 2.

[0074] Comparative Example 5

[0075] The difference between the indicator ink of this comparative example and Example 3 is that 1-ethyl-3-methylimidazolium tetrafluoroborate is not contained, and other component parameters are the same as those of Example 3.

[0076] Comparative Example 6

[0077] The difference between the indicator ink of this comparative example and Example 3 is that the indicator ink does not contain silicone microcapsules, that is, the developer is not encapsulated inside the silicone microcapsules. Other component parameters are the same as those of Example 3.

[0078] The indicator inks of the examples and comparative examples were tested for performance using the following test methods:

[0079] 1. Color Change Time: The components of the indicator inks of the Examples and Comparative Examples were mixed uniformly and stored in an inkjet printer cartridge. The ink was then printed onto a PET film substrate using an Epson inkjet printer to form a rectangular test pattern (approximately 10 × 10 mm). After drying, the sample was placed in a H2O2 plasma sterilizer and the standard sterilization procedure was initiated. The color change of the sample was observed visually or recorded with a high-resolution camera. The time from the start of sterilization to the color reaching a stable final state was recorded (in seconds). The test was repeated three times and the average value was taken.

[0080] 2. Color contrast ΔE: Test equipment: Spectrophotometer (X-Rite Ci64, with D65 illuminant, 10° viewing angle), white background (compliant with ISO 7724);

[0081] Test steps: For the inkjet printed sample, record the initial color coordinates (L1, a1, b1) before sterilization. Remove the sample immediately after sterilization and record the final color coordinates (L2, a2, b2).

[0082] Calculate ΔE using the following formula:

[0083] The test was repeated 3 times and the average value was taken;

[0084] The color coordinates L, a, and b are measured using a D65 illuminant and a 10° viewing angle.

[0085] 3. Storage stability: Test equipment: Constant temperature and humidity test chamber (settings: 25°C ± 2°C, relative humidity 60% ± 5%); several inkjet-printed samples of the indicator inks of the examples and comparative examples were placed in ink cartridges and sealed for storage;

[0086] Test steps: Record the color ΔE0 of the inkjet sample in the initial state (color value after printing and drying but before sterilization), store the ink and printed samples in a constant temperature and humidity chamber for 6 months,

[0087] Sample prints or reprint and measure color ΔE1 once a month.

[0088] Calculate the color attenuation percentage:

[0089] Color attenuation=|ΔE1-ΔE0| / ΔE0×100%.

[0090] The test results are shown in Table 1.

[0091] Table 1 Performance test results of the embodiments and comparative examples

[0092]

[0093]

[0094] As can be seen from Table 1, the indicator ink of the present invention has excellent storage stability and high sensitivity, clear color change, intuitive interpretation, and can be used for H2O2 plasma sterilization indication.

[0095] Compared with the examples, the lack of ionic liquid in the comparative examples significantly slowed the color development reaction of the indicator ink, significantly reduced color contrast, deteriorated ink stability, and exhibited significant precipitation, seriously impacting the lifespan of the indicator card. The lack of a microencapsulating agent also increased the color change time of the indicator ink, resulting in uneven localized color change, significant background interference, poor color change sensitivity, and decreased storage stability.

[0096] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit the scope of protection of the present invention. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that the technical solutions of the present invention may be modified or replaced by equivalents without departing from the essence and scope of the technical solutions of the present invention.

Claims

1. An indicator ink, characterized in that: The invention comprises the following components in parts by weight: 0.5 to 15 parts of a metal oxide catalyst, 40 to 80 parts of an ionic liquid, 0.1 to 3 parts of a viscosity regulator, and 1 to 10 parts of a microcapsule encapsulating agent; the microcapsule encapsulating agent comprises a polymer shell and a sterilization color-changing developer encapsulated inside the polymer shell.

2. The indicator ink according to claim 1, characterized in that The metal oxide catalyst includes at least one of Fe2O3, ZnO, TiO2, and CeO2.

3. The indicator ink according to claim 1, characterized in that The ionic liquid includes at least one of 1-ethyl-3-methylimidazolium tetrafluoroborate, 1-butyl-3-methylimidazolium hexafluorophosphate, and 1-ethyl-3-methylimidazolium methanesulfonate.

4. The indicator ink according to claim 1, characterized in that The polymer shell includes at least one of silicone polymer, polyurea, and polymethacrylate; and / or the weight portion of the sterilization color-changing developer is 0.1 to 5 parts.

5. The indicator ink according to claim 1, characterized in that The sterilization color-changing color developer includes at least one of rhodamine B, bromophenol green, bromophenol blue, neutral red, methyl violet or methylene blue; and / or the viscosity modifier includes at least one of ethylene glycol, glycerol or propylene glycol.

6. The indicator ink according to claim 1, characterized in that The metal oxide catalyst includes at least one of TiO2 and CeO2; and / or the ionic liquid is 1-ethyl-3-methylimidazolium tetrafluoroborate; and / or the polymer shell is a siloxane polymer.

7. The indicator ink according to claim 4 or 6, characterized in that The preparation method of a microcapsule encapsulating agent with a silicone polymer as a polymer shell comprises the following steps: reacting methyltriethoxysilane and ethyl orthosilicate under the catalytic action of a base, adding the sterilization color-changing developer, continuing the reaction, and drying to obtain the microcapsule encapsulating agent with a silicone polymer as a polymer shell.

8. The indicator ink according to claim 7, characterized in that The molar ratio of methyltriethoxysilane to ethyl orthosilicate is (1-5):1; and / or the base includes aqueous ammonia; and / or the reaction temperature is 35°C-45°C, and the reaction time is 1.5h-2.5h; and / or the reaction time is 0.5h-1.5h.

9. Use of the indicator ink according to any one of claims 1 to 8 in peroxide plasma sterilization indicator products.

10. A sterilization indicator card, characterized in that: The sterilization indicator card comprises a substrate and the indicator ink according to any one of claims 1 to 8 which is inkjet printed on the substrate.

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