Preparation method of low-pollution temperature change ink

Abstract

The invention discloses a low-pollution temperature change ink preparation method, and belongs to the technical field of temperature change ink preparation, and the method comprises the following steps: S1, raw material selection and treatment; s2, solvent selection and formula optimization; s3, microcapsule application; s4, enhancing the nano material; s5, catalyst utilization and reaction conditions; and S6, performing a continuous production process. By using the bio-based material and the water-based solvent, the emission of harmful substances is reduced, the environmental pollution risk is reduced, the color conversion efficiency, stability and definition of the ink are remarkably improved by applying the microcapsule technology and the nano material, the user experience is enhanced, and the application prospect is wide. And due to the application of the efficient catalyst and the microwave-assisted heating technology, the production period is shortened, the energy consumption and the production cost are reduced, and the production efficiency is improved.

Description

Technical Field

[0001] The invention belongs to the technical field of temperature-variable ink preparation, in particular to a method for preparing low-pollution temperature-variable ink. Background Art

[0002] Temperature-sensitive inks (also known as thermosensitive inks) change color within a specific temperature range and are primarily used in the printing and packaging industries. They are widely used in security labels, temperature indicators, smart packaging, children's toys, and other fields. Their purpose is to provide intuitive feedback through color changes, such as indicating whether food packaging has reached a safe storage temperature or indicating whether a product has been subjected to high-temperature treatment on a security label.

[0003] Traditional temperature-sensitive inks typically use petroleum-based materials as their primary ingredients. The production of these materials requires extensive chemical reactions and high-temperature processing, which can easily produce harmful byproducts. For example, the synthesis of petroleum-based polymers produces volatile organic compounds (VOCs) and other toxic gases. These processes often rely on energy-intensive and highly polluting equipment and technologies, such as high-temperature cracking and catalytic polymerization. These processes not only consume significant amounts of energy but also emit significant amounts of greenhouse gases and pollutants.

[0004] The emission of these harmful substances can pollute the air, water, and soil, and long-term accumulation can lead to serious ecological problems. For example, the emission of VOCs can form photochemical smog, which affects air quality and harms human health. Summary of the Invention

[0005] The object of the present invention is to provide a method for preparing a low-pollution temperature-variable ink to solve the problems raised in the background technology.

[0006] To achieve the above object, the present invention provides the following technical solution: a method for preparing a low-pollution temperature-variable ink, comprising the following steps:

[0007] S1: Raw material selection and processing: Select starch and cellulose bio-based materials as the main components of ink, and convert biomass into slurry for ink use through enzymatic hydrolysis or chemical treatment methods;

[0008] S2: Solvent selection and formulation optimization: Use water-based solvents or alcohol solvents instead of traditional organic solvents, and adjust the ratio of solvent to pigment to ensure the dispersibility and adhesion of the ink during the printing process;

[0009] S3: Microcapsule application: Microcapsules with multilayer wall structures or multicomponent composite materials are prepared by interfacial polymerization or spray drying, in which the thermosensitive dye is dissolved in the oil phase and mixed with the aqueous phase containing the wall material precursor to form stable microcapsules;

[0010] S4: Nanomaterial enhancement: introducing quantum dots or metal oxide nanoparticles and dispersing them evenly into the ink using ultrasonic dispersion or ball milling;

[0011] S5: Catalyst utilization and reaction conditions: The catalyst is used and microwave-assisted heating technology is used to accelerate key chemical reactions, shorten production cycles and reduce energy consumption. The high-efficiency catalyst is a transition metal complex or an ionic liquid catalyst. The reaction temperature is 80-120°C, the pressure is 0.5-1.5 atm, and the reaction time is 1-3 hours.

[0012] S6: Continuous production process: A fully automated production line from raw material feeding, mixing, reaction to finished product packaging to achieve continuous and uninterrupted operation.

[0013] In this solution, the enzymatic hydrolysis technology is preferably carried out at 40-60°C for a reaction time of 2-4 hours. After the starch is decomposed into small molecular sugars, a polymerization reaction is performed to form a bio-based ink having the required viscosity (50-100 mPa·s) and fluidity. The polymerization reaction temperature is 60-90°C and the reaction time is 2-3 hours.

[0014] In this solution, the aqueous solvent or alcohol solvent is selected from low-volatile organic compounds such as ethylene glycol monobutyl ether and propylene glycol methyl ether, and a surfactant is added to improve the leveling and wettability of the ink.

[0015] Preferably, the wall material of the microcapsules is selected from polyurethane / polyurea and gelatin / gum arabic composite materials, the particle size of the microcapsules is controlled within the range of 1-10 μm, and the effect of different wall material thicknesses on the thermal stability of the microcapsules is studied experimentally to ensure color persistence at different temperatures.

[0016] In this solution, the nanomaterial is preferably selected from quantum dots, metal oxide nanoparticles of titanium dioxide or zinc oxide, and is dispersed into the ink system by ultrasonic dispersion or ball milling to ensure the stability and consistency of the nanomaterial in the ink;

[0017] The mass fraction of the nano material is 0.5%-5%, and the ultrasonic dispersion time is 1-3 hours.

[0018] In this solution, the catalyst is preferably a transition metal complex or an ionic liquid catalyst, and the desired reaction conditions are found by adjusting the reaction temperature (80-120° C.), pressure (0.5-1.5 atm) and time (1-3 hours).

[0019] Preferably, the continuous production process equipment is selected from a continuous reactor, an automatic coating machine, etc., and key parameters in the production process are monitored in real time through online monitoring to ensure consistency of product quality, and a benefit analysis is performed to verify its economy and feasibility.

[0020] Preferably, the online monitoring system includes a temperature sensor, a pressure sensor, a flow meter, etc., to ensure that the temperature fluctuation during the production process does not exceed ±2°C and the pressure fluctuation does not exceed ±0.1atm.

[0021] Preferably, the novel dye combination selects thermosensitive dyes with complementary colors, and by gradually increasing the proportion of one dye and observing its effect on the overall color change, it is ensured that a sharp color contrast is produced within a specific temperature range.

[0022] Preferably, the precise formula adjustment of this solution includes accurately measuring the content of each component, including pigments, dyes, solvents, and additives, and adjusting the ink formula according to the requirements of different application scenarios so that it emits bright fluorescence under the required light source.

[0023] Compared with the prior art, the technical effects and advantages of the present invention are:

[0024] This low-pollution method for preparing temperature-sensitive inks uses bio-based materials such as starch and cellulose as the main components of the ink, and converts the biomass into a slurry suitable for ink use through enzymatic hydrolysis or chemical treatment. For example, corn starch undergoes enzymatic hydrolysis and polymerization to form a bio-based ink with appropriate viscosity (50-100 mPa·s) and fluidity. Traditional temperature-sensitive inks typically use petroleum-based materials as their main components. These materials produce a large amount of harmful substances during production and disposal, causing serious environmental pollution. Bio-based materials not only have good biodegradability, reducing environmental pollution, but also provide comparable performance to traditional petroleum-based materials, such as appropriate viscosity and fluidity, ensuring good ink performance during the printing process.

[0025] By precisely adjusting the ratio of solvent to pigment and adding an appropriate amount of surfactant to improve the ink's leveling and wettability, we ensure uniform ink spreading and strong adhesion during the printing process. The use of water-based and alcohol-based solvents significantly reduces VOC emissions, lowering environmental pollution risks, while also improving the ink's printing quality and stability.

[0026] Microcapsules are prepared using a gelatin / gum arabic composite as the wall material via interfacial polymerization. A thermosensitive dye is first dissolved in an oil phase, then mixed with an aqueous phase containing the wall material precursor. Stirring and heating allow the wall material to form microcapsules at the interface. The application of microencapsulation technology significantly improves the ink's color conversion efficiency and stability, ensuring color durability at varying temperatures and extending the product's lifespan.

[0027] Titanium dioxide nanoparticles (mass fraction of 0.5%-5%) are used and dispersed for 1-3 hours using an ultrasonic disperser to ensure that the nanoparticles are evenly dispersed in the ink system. The addition of nanomaterials significantly improves the color change speed and clarity of the ink, making the ink show more distinct color contrast when the temperature changes, enhancing the user experience. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the specific embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0029] Figure 1 The present invention is a flow chart of a method for preparing a low-pollution temperature-variable ink. DETAILED DESCRIPTION

[0030] In the following description, numerous specific details are provided to provide a more thorough understanding of the present invention. However, it will be apparent to those skilled in the art that the present invention may be practiced without one or more of these details. In other instances, certain technical features well known in the art are not described to avoid confusion with the present invention.

[0031] Unless otherwise defined, the directions of up, down, left, right, front, back, inside and outside involved in this document are based on the directions of up, down, left, right, front, back, inside and outside shown in the figures of the present invention, and are explained here together.

[0032] This embodiment provides Figure 1 A method for preparing a low-pollution temperature-variable ink is shown, comprising the following steps:

[0033] S1: Raw material selection and processing: Starch and cellulose bio-based materials are selected as the main components of the ink, and the biomass is converted into a slurry for ink use through enzymatic hydrolysis or chemical treatment. The starch is derived from corn, potato or cassava, and the cellulose is derived from wood or cotton. The enzymatic hydrolysis technology is carried out at 40-60°C and the reaction time is 2-4 hours;

[0034] S2: Solvent selection and formulation optimization: Use aqueous solvents or alcohol solvents instead of traditional organic solvents, and adjust the ratio of solvent to pigment to ensure the dispersibility and adhesion of the ink during the printing process. The aqueous solvent is ethylene glycol monobutyl ether or propylene glycol methyl ether, and a surfactant (e.g., 0.1%-1% by mass) is added to improve leveling and wettability.

[0035] S3: Microcapsule application: Microcapsules with multi-layer wall structures or multi-component composite materials are prepared by interfacial polymerization or spray drying, in which the thermosensitive dye is dissolved in the oil phase and mixed with the water phase containing the wall material precursor to form stable microcapsules. The thickness of the microcapsule wall material is controlled between 0.5-3μm and the particle size is controlled within the range of 1-10μm;

[0036] S4: Nanomaterial enhancement: Introducing quantum dots or metal oxide nanoparticles and uniformly dispersing them into the ink using ultrasonic dispersion or ball milling to improve the speed and clarity of color change; the mass fraction of the nanomaterial is 0.5%-5%, and the ultrasonic dispersion time is 1-3 hours;

[0037] S5: Catalyst utilization and reaction conditions: The catalyst is used and microwave-assisted heating technology is used to accelerate key chemical reactions, shorten production cycles and reduce energy consumption. The high-efficiency catalyst is a transition metal complex or an ionic liquid catalyst. The reaction temperature is 80-120°C, the pressure is 0.5-1.5 atm, and the reaction time is 1-3 hours.

[0038] S6: Continuous production process: A fully automated production line from raw material feeding, mixing, reaction to finished product packaging, achieving continuous and uninterrupted operation. The key parameters of the production process are monitored in real time through an online monitoring system to ensure the consistency of product quality.

[0039] In this embodiment, the selection of bio-based materials not only reduces environmental pollution but also improves the physical properties of the ink (such as viscosity and fluidity) to a certain extent. For example, the slurry formed by enzymatic hydrolysis and polymerization of corn starch has good fluidity and stability, which helps improve the printing quality of the ink. When bio-based materials are used as the main component, the application of nanomaterials can further improve the color change speed and clarity of the ink. This combination not only improves environmental performance but also achieves efficient color change in terms of functionality.

[0040] In this embodiment, the multi-layered microcapsules not only provide excellent color conversion effects but also enhance the ink's durability and resistance to environmental changes. For example, the gelatin / gum arabic composite wall material not only stabilizes heat-sensitive dyes but also prevents them from degrading or losing effectiveness during storage. The combination of microencapsulation technology and nanomaterials enables the ink to not only rapidly change color with temperature fluctuations but also maintain color stability over time. This combination can significantly extend the product's lifespan and reduce quality issues caused by color fading.

[0041] In the present embodiment, efficient catalyst not only shortens the production cycle and reduces energy consumption, but also can play a greater role in continuous production process. For example, copper complex catalyst can accelerate the reaction at a lower temperature, so that the entire production line can be operated under milder conditions, thereby extending the life of the equipment and reducing maintenance costs. The combination of continuous production process and online monitoring system ensures that the parameter control in the production process is more accurate, further improving the consistency of product quality. In addition, the application of efficient catalyst makes the operation of the continuous production line more stable, reducing downtime and failure rate.

[0042] In this embodiment, the enzyme-catalyzed hydrolysis technology is carried out at 40-60°C, and the reaction time is 2-4 hours. After the starch is decomposed into small molecular sugars, a bio-based ink having the desired viscosity (50-100mPa·s) and fluidity is formed by polymerization reaction, and the polymerization reaction temperature is 60-90°C and the time is 2-3 hours. The enzyme-catalyzed hydrolysis technology can not only convert biomass into a slurry suitable for ink use, but also optimize the viscosity and fluidity of the slurry by adjusting the reaction conditions (such as temperature and time). For example, enzyme-catalyzed hydrolysis at 50°C for 3 hours can obtain a slurry with good fluidity. The product after enzyme-catalyzed hydrolysis is then formed into an ink with appropriate viscosity through polymerization reaction. This combination not only improves the fluidity of the ink, but also enhances its printability.

[0043] In this embodiment, the aqueous solvent or alcohol solvent is selected from low volatile organic compounds (LVOCs) such as ethylene glycol monobutyl ether and propylene glycol methyl ether, and the leveling and wettability of the ink are improved by adding a surfactant (such as 0.1%-1% by mass); the surfactant is selected from polyoxyethylene alkyl ether, sodium lauryl sulfate, etc., and its amount is adjusted according to different ink formulas.

[0044] In this embodiment, the wall material of the microcapsule is selected from polyurethane / polyurea and gelatin / gum arabic composite materials, the particle size of the microcapsule is controlled in the range of 1-10 μm, and the effect of different wall material thicknesses on the thermal stability of the microcapsules is studied experimentally to ensure color persistence at different temperatures; the wall material thickness of the microcapsule is controlled between 0.5-3 μm, preferably 1.5-2 μm.

[0045] In this embodiment, the nanomaterial is selected from quantum dots, metal oxide nanoparticles of titanium dioxide or zinc oxide, and is dispersed into the ink system by ultrasonic dispersion or ball milling to ensure the stability and consistency of the nanomaterial in the ink;

[0046] The mass fraction of the nanomaterial is 0.5%-5%, and the ultrasonic dispersion time is 1-3 hours, preferably 2 hours.

[0047] In this embodiment, the catalyst is a transition metal complex or an ionic liquid catalyst, and the desired reaction conditions are found by adjusting the reaction temperature (80-120°C), pressure (0.5-1.5atm) and time (1-3 hours) to shorten the production cycle and reduce energy consumption; the transition metal complex is selected from complexes of metals such as copper, nickel, and cobalt, and the ionic liquid catalyst is selected from imidazole ionic liquids. The preferred reaction temperature is 90-100°C, the preferred pressure is 1atm, and the preferred time is 2 hours.

[0048] In this embodiment, the continuous production process equipment is selected from a continuous reactor, an automatic coating machine, etc., and key parameters in the production process are monitored in real time through online monitoring to ensure the consistency of product quality, and a benefit analysis is performed to verify its economy and feasibility.

[0049] In this embodiment, the online monitoring system includes a temperature sensor, a pressure sensor, a flow meter, etc., to ensure that the temperature fluctuation during the production process does not exceed ±2°C and the pressure fluctuation does not exceed ±0.1atm.

[0050] In this embodiment, the novel dye combination selects thermosensitive dyes with complementary colors, such as red and green, blue and yellow, and by gradually increasing the proportion of a dye (0.5%-5% mass fraction), observing its effect on the overall color change, ensuring that a sharp color contrast is produced within a specific temperature range; the adjustment range of the dye ratio is 0.5%-5%, preferably 2%-3%, and long-term stability tests are carried out under different temperature conditions to ensure that it can still maintain good color performance under different temperature and humidity conditions. Selecting thermosensitive dyes with complementary colors can not only produce sharp color contrast, but also optimize the overall color change effect by gradually increasing the proportion of a dye. For example, the initial ratio of red and green dyes is 1:1, and gradually increasing the proportion of red dye to 3% can significantly enhance the visual effect of color change. The combination of novel dye combination and nanomaterials enables the ink to not only change color quickly when the temperature changes, but also maintain long-term color stability. This combination can significantly extend the service life of the product and reduce quality problems caused by color fading.

[0051] In this embodiment, the precise formula adjustment includes accurately measuring the content of each component, including pigments, dyes, solvents, and additives, and adjusting the ink formula according to the requirements of different application scenarios, such as adding an appropriate amount of fluorescent agent (0.01%-0.1% mass fraction) to make it emit bright fluorescence under the required light source; the fluorescent agent is selected from fluorescent yellow and fluorescent green, and its mass fraction is 0.01%-0.1%, preferably 0.05% by mass.

[0052] It should be noted that, in this article, relational terms such as one and two are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device that includes a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions. The sentence "including an element defined by ... does not exclude the presence of other identical elements in the process, method, article or device that includes the element."

[0053] While embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions, and variations may be made to these embodiments without departing from the principles and spirit of the invention, and that the scope of the invention is defined by the appended claims and their equivalents.

Claims

1. A method for preparing a low-pollution temperature-variable ink, characterized in that: The following steps are involved: S1: Raw material selection and processing: Select starch and cellulose bio-based materials as the main components of ink, and convert biomass into slurry for ink through enzymatic hydrolysis or chemical treatment; S2: Solvent selection and formulation optimization: Use water-based solvents or alcohol solvents instead of traditional organic solvents, and adjust the ratio of solvent to pigment to ensure the dispersibility and adhesion of the ink during the printing process; S3: Application of microcapsules: Microcapsules with multi-layer wall structures or multi-component composite materials are prepared by interfacial polymerization or spray drying, in which the thermosensitive dye is dissolved in the oil phase and mixed with the water phase containing the wall material precursor to form stable microcapsules; S4: Nanomaterial enhancement: introducing quantum dots or metal oxide nanoparticles and dispersing them evenly into the ink using ultrasonic dispersion or ball milling; S5: Catalyst utilization and reaction conditions: The key chemical reactions are accelerated by using catalysts and microwave-assisted heating technology, shortening the production cycle and reducing energy consumption. The high-efficiency catalyst is a transition metal complex or an ionic liquid catalyst. The reaction temperature is 80-120°C, the pressure is 0.5-1.5 atm, and the reaction time is 1-3 hours. S6: Continuous production process: A fully automated production line from raw material feeding, mixing, reaction to finished product packaging to achieve continuous and uninterrupted operation.

2. The method for preparing a low-pollution temperature-variable ink according to claim 1, characterized in that: The enzyme-catalyzed hydrolysis technology is carried out at 40-60°C and the reaction time is 2-4 hours. After the starch is decomposed into small molecular sugars, a polymerization reaction is performed to form a bio-based ink with the required viscosity (50-100 mPa·s) and fluidity. The polymerization reaction temperature is 60-90°C and the reaction time is 2-3 hours.

3. A method for preparing a low-pollution temperature-variable ink according to claim 2, characterized in that: The aqueous solvent or alcohol solvent is selected from low-volatile organic compounds such as ethylene glycol monobutyl ether and propylene glycol methyl ether, and a surfactant is added to improve the leveling and wettability of the ink.

4. The method for preparing a low-pollution temperature-variable ink according to claim 3, characterized in that: The wall material of the microcapsule is selected from polyurethane / polyurea and gelatin / gum arabic composite materials, the particle size of the microcapsule is controlled within the range of 1-10 μm, and the influence of different wall material thicknesses on the thermal stability of the microcapsule is studied experimentally to ensure color persistence at different temperatures.

5. A method for preparing a low-pollution temperature-variable ink according to claim 4, characterized in that: The nanomaterial is selected from quantum dots, metal oxide nanoparticles of titanium dioxide or zinc oxide, and is dispersed into the ink system by ultrasonic dispersion or ball milling to ensure the stability and consistency of the nanomaterial in the ink; The mass fraction of the nano material is 0.5%-5%, and the ultrasonic dispersion time is 1-3 hours.

6. A method for preparing a low-pollution temperature-variable ink according to claim 5, characterized in that: The catalyst is a transition metal complex or an ionic liquid catalyst, and the desired reaction conditions are found by adjusting the reaction temperature (80-120° C.), pressure (0.5-1.5 atm) and time (1-3 hours).

7. A method for preparing a low-pollution temperature-variable ink according to claim 6, characterized in that: The continuous production process equipment is selected from a continuous reactor, an automatic coating machine, etc., and the key parameters in the production process are monitored in real time through online monitoring to ensure the consistency of product quality, and a benefit analysis is performed to verify its economy and feasibility.

8. The method for preparing a low-pollution temperature-variable ink according to claim 7, characterized in that: The online monitoring system includes temperature sensors, pressure sensors, flow meters, etc., to ensure that the temperature fluctuation during the production process does not exceed ±2°C and the pressure fluctuation does not exceed ±0.1atm.

9. A method for preparing a low-pollution temperature-variable ink according to claim 8, characterized in that: The novel dye combination selects thermosensitive dyes with complementary colors, and gradually increases the proportion of one dye to observe its effect on the overall color change, thereby ensuring a sharp color contrast within a specific temperature range.

10. The method for preparing a low-pollution temperature-variable ink according to claim 8, characterized in that: The precise formula adjustment includes accurately measuring the content of each component, including pigments, dyes, solvents, and additives, and adjusting the ink formula according to the requirements of different application scenarios so that it emits bright fluorescence under the required light source.

Images