Environment-friendly thermosensitive coating for three-proofing PP (polypropylene) synthetic paper label and preparation process of environment-friendly thermosensitive coating

Abstract

The invention discloses an environment-friendly thermosensitive coating for a three-proofing PP (polypropylene) synthetic paper label, which comprises an environment-friendly thermosensitive coating body formed by mixing and spraying a plurality of ingredients, the environment-friendly water-based ink is prepared from the following ingredients in parts by weight: 25 to 35 parts of water-based acrylic resin, 10 to 20 parts of polyurethane resin, 10 to 15 parts of environment-friendly pigment, 15 to 30 parts of environment-friendly filler, 8 to 12 parts of sensitizer, 4 to 8 parts of lubricant, 5 to 10 parts of stabilizer, 3 to 5 parts of dispersing agent, 5 to 10 parts of defoaming agent and 10 to 20 parts of color developing agent. The hindered phenol antioxidant and the ultraviolet light absorber are added into the thermosensitive coating, so that the stability of the coating is improved, the thermosensitive coating is high in ultraviolet absorption capacity and good in stability due to use of the ultraviolet light absorber, the outdoor service life of the coating can be effectively prolonged, discoloration, pulverization and aging are prevented, and the service life of the coating is prolonged. Benzoic acid and salicylic acid are added into the thermosensitive coating to serve as color developing agents, so that the thermosensitive coating is environment-friendly and environment-friendly to use, toxicity is low compared with bisphenol A, and harm to a human body is reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of thermosensitive coatings, and in particular to an environmentally friendly thermosensitive coating for triple-proof PP synthetic paper labels and a preparation process thereof. Background Art

[0002] The triple-proof PP synthetic paper label is a label with waterproof, oil-proof and tear-proof (referred to as "triple-proof") properties. It is usually made of PP (polypropylene) synthetic paper material and coated with a corresponding heat-sensitive coating.

[0003] Early thermal coating formulations are sensitive to heat, wear, friction, light and water, which can easily cause printed images to fade. Although the stability of later thermal coating formulations has been improved, thermal printing usually fades faster than other printing methods. In practice, thermally printed text should remain legible for at least 50 days, but in some specific environments, such as long-term exposure to sunlight or high temperature environments, fading may be more obvious, reducing the effectiveness of the three-proof PP synthetic paper labels. In addition, existing thermal coatings contain bisphenol A, which is a low-toxic chemical. Long-term contact with personnel will cause damage to the human body and endanger personnel health.

[0004] Therefore, the present application proposes an environmentally friendly thermosensitive coating for triple-proof PP synthetic paper labels and a preparation process thereof. Summary of the invention

[0005] The purpose of the present invention is to solve the shortcomings of the prior art and to propose an environmentally friendly heat-sensitive coating for triple-proof PP synthetic paper labels and a preparation process thereof.

[0006] In order to achieve the above-mentioned purpose, the main technical scheme adopted by the present invention includes: an environmentally friendly thermosensitive coating for a three-proof PP synthetic paper label, including an environmentally friendly thermosensitive coating body, the environmentally friendly thermosensitive coating body is used to prepare a three-proof PP synthetic paper label, and the environmentally friendly thermosensitive coating body is sprayed by mixing multiple ingredients, and the multiple ingredient components and weight portions include: 25-35 parts of water-based acrylic resin, 10-20 parts of polyurethane resin, 10-15 parts of environmentally friendly pigment, 15-30 parts of environmentally friendly filler, 8-12 parts of sensitizer, 4-8 parts of lubricant, 5-10 parts of stabilizer, 3-5 parts of dispersant, 5-10 parts of defoaming agent and 10-20 parts of developer.

[0007] Preferably, the environmentally friendly pigment comprises titanium dioxide and zinc oxide, the mass ratio of the titanium dioxide to the zinc oxide is 4:2, and the particle sizes of the titanium dioxide and the zinc oxide are controlled within 60 μm.

[0008] Preferably, the environmentally friendly filler comprises calcium carbonate and silicon dioxide, and the mass ratio of the calcium carbonate to the silicon dioxide is 1:1.

[0009] Preferably, the sensitizer is benzenesulfonic acid amide.

[0010] Preferably, the lubricant is dimethyl silicone oil.

[0011] Preferably, the stabilizer comprises a hindered phenol antioxidant and an ultraviolet absorber, and the mass ratio of the hindered phenol antioxidant to the ultraviolet absorber is 2:1.

[0012] Preferably, the dispersant comprises sodium polyacrylate and sodium alkylbenzene sulfonate, and the mass ratio of the sodium polyacrylate to the sodium alkylbenzene sulfonate is 1:1.

[0013] Preferably, the defoaming agent includes an organosilicon defoaming agent and a mineral oil defoaming agent, and the mass ratio of the organosilicon defoaming agent to the mineral oil defoaming agent is 1:1.

[0014] Preferably, the developer comprises benzoic acid and salicylic acid, and the mass ratio of the benzoic acid to the salicylic acid is 1:1.

[0015] The present invention also provides a preparation process of an environmentally friendly heat-sensitive coating for a triple-proof PP synthetic paper label, comprising the following preparation steps:

[0016] S1, select sodium polyacrylate and sodium alkylbenzene sulfonate with a formula ratio, dissolve the sodium polyacrylate and sodium alkylbenzene sulfonate in water to obtain a dispersed solution, and divide the dispersed solution into four parts;

[0017] S2, adding a formulated amount of titanium dioxide and zinc oxide into one of the dispersed solutions in S1, mixing and dispersing for more than 15 minutes to prepare a pigment dispersion;

[0018] S3, adding a formulated amount of titanium dioxide, zinc oxide and dimethyl silicone oil into one of the dispersed solutions in S1, mixing and dispersing for more than 40 minutes to prepare a filler dispersion;

[0019] S4, adding the formulated amount of benzenesulfonic acid amide, benzoic acid and salicylic acid into one of the dispersed solutions in S1, mixing and dispersing for more than 15 minutes to prepare a color-developing dispersed solution;

[0020] S5, adding a formula amount of hindered phenol antioxidant, ultraviolet absorber, silicone defoamer and mineral oil defoamer into one of the dispersed solutions in S1, mixing and dispersing for more than 30 minutes to prepare a defoaming dispersion;

[0021] S6, pour the pigment dispersion in S2, the filler dispersion in S3, the color development dispersion in S4, the defoaming dispersion in S5, and the formulated amount of water-based acrylic resin and polyurethane resin into the interior of the mixing device, and mix and disperse for more than 20 minutes to obtain an environmentally friendly thermal-sensitive coating;

[0022] Among them, the mixing device includes a mixing tank, the top of the mixing tank is provided with a feed port, the bottom of the mixing tank is fixedly installed with a discharge pipe, the discharge pipe is fixedly installed with a valve, the top of the mixing tank is fixedly installed with a drive motor, the output shaft of the drive motor extends into the interior of the mixing tank and is fixedly connected to a stirring rod through a coupling, the stirring rod is fixedly connected with a connecting rod, one end of the connecting rod is fixedly connected to a mounting plate by bolts, a rubber scraper is fixedly installed on the mounting plate, and the rubber scraper is in contact with the inner wall of the mixing tank.

[0023] The present invention has at least the following beneficial effects:

[0024] 1. Adding hindered phenol antioxidants and UV absorbers to the thermal coating helps to improve the stability of the coating and prevent deterioration during storage and use. Hindered phenol antioxidants can capture free radicals and interrupt the auto-oxidation chain reaction, thereby preventing the water-based acrylic resin and polyurethane resin components in the coating from being oxidized and degraded. They have high thermal stability and antioxidant efficiency and can effectively protect the performance of the coating under high temperature and long-term storage conditions. In addition, hindered phenol antioxidants have good compatibility with other components in the thermal coating, are not easy to volatilize and migrate, and have little effect on color and thermal properties. The use of UV absorbers makes the thermal coating have strong UV absorption capacity, good stability, and is not easy to volatilize and migrate, which can effectively extend the outdoor service life of the coating and prevent discoloration, powdering and aging.

[0025] 2. By adding benzoic acid and salicylic acid as color developers in the heat-sensitive coating, benzoic acid and salicylic acid have good thermal stability and chemical stability, and can produce more durable colors after reacting with leuco dyes. They are environmentally friendly and environmentally friendly to use. Compared with bisphenol A, they are less toxic and reduce harm to the human body.

[0026] 3. By adding titanium dioxide and zinc oxide as pigments in the thermal coating, titanium dioxide has high hiding power, good dispersibility and weather resistance, and zinc oxide has good hiding power and whiteness. The combination of titanium dioxide and zinc oxide can improve the weather resistance and antibacterial properties of the thermal coating. In addition, titanium dioxide and zinc oxide are non-toxic and harmless, environmentally friendly, and increase the environmental performance of use. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] The drawings described herein are used to provide a further understanding of the present application and constitute a part of the present application. The illustrative embodiments of the present application and their descriptions are used to explain the present application and do not constitute an improper limitation on the present application. In the drawings:

[0028] Figure 1 The present invention is a flow chart for preparing an environmentally friendly heat-sensitive coating for a triple-proof PP synthetic paper label;

[0029] Figure 2 The present invention is a schematic structural diagram of a mixing device for preparing an environmentally friendly heat-sensitive coating for a triple-proof PP synthetic paper label.

[0030] Description of Figure Numbers:

[0031] 1. Mixing tank; 2. Feed inlet; 3. Discharge pipe; 4. Valve; 5. Drive motor; 6. Stirring rod; 7. Connecting rod; 8. Mounting plate; 9. Rubber scraper; 10. Observation window. DETAILED DESCRIPTION

[0032] The following will describe the implementation methods of the present application in detail with the help of accompanying drawings and examples, so that the implementation process of how the present application uses technical means to solve technical problems and achieve technical effects can be fully understood and implemented accordingly.

[0033] Please refer to Figure 1 to Figure 2 As shown, an embodiment of the present invention provides an environmentally friendly thermosensitive coating for a triple-proof PP synthetic paper label, including an environmentally friendly thermosensitive coating body, the environmentally friendly thermosensitive coating body is used to prepare a triple-proof PP synthetic paper label, and the environmentally friendly thermosensitive coating body is sprayed by mixing multiple ingredients, and the multiple ingredient components and weight portions include: 25-35 parts of water-based acrylic resin, 10-20 parts of polyurethane resin, 10-15 parts of environmentally friendly pigment, 15-30 parts of environmentally friendly filler, 8-12 parts of sensitizer, 4-8 parts of lubricant, 5-10 parts of stabilizer, 3-5 parts of dispersant, 5-10 parts of defoaming agent and 10-20 parts of developer.

[0034] Among them, environmentally friendly pigments include titanium dioxide and zinc oxide. The mass ratio of titanium dioxide and zinc oxide is 4:2. The particle size of titanium dioxide and zinc oxide is controlled within 60μm. Titanium dioxide has high hiding power, good dispersibility and weather resistance. Zinc oxide has good hiding power and whiteness. The combination of titanium dioxide and zinc oxide can improve the weather resistance and antibacterial properties of heat-sensitive coatings. In addition, titanium dioxide and zinc oxide are non-toxic and harmless, environmentally friendly, and increase the environmental performance of use.

[0035] Among them, environmentally friendly fillers include calcium carbonate and silicon dioxide. The mass ratio of calcium carbonate and silicon dioxide is 1:1. Calcium carbonate has good hiding power and whiteness, which can improve the opacity of paper and the contrast between image and background color. Silicon dioxide can improve the hardness and wear resistance of the coating, and also has certain anti-stickiness. In addition, calcium carbonate and silicon dioxide are non-toxic and harmless, environmentally friendly, and increase the environmental performance of use.

[0036] Among them, the sensitizer is benzenesulfonic acid amide, which can improve the thermal sensitivity of the coating, so that the coating can quickly develop color at a lower temperature, thereby improving the clarity and speed of printing.

[0037] Among them, the lubricant is dimethyl silicone oil, which is colorless, odorless, non-toxic, and environmentally friendly. The lubricant can be used to prevent the thermal head from sticking and reduce friction during the printing process.

[0038] Among them, the stabilizer includes hindered phenol antioxidants and UV absorbers, the mass ratio of hindered phenol antioxidants and UV absorbers is 2:1, hindered phenol antioxidants and UV absorbers help to improve the stability of the coating and prevent deterioration during storage and use, hindered phenol antioxidants can capture free radicals and interrupt the auto-oxidation chain reaction, thereby preventing the water-based acrylic resin and polyurethane resin components in the coating from being oxidized and degraded, having high thermal stability and antioxidant efficiency, and can effectively protect the performance of the coating under high temperature and long-term storage conditions. In addition, hindered phenol antioxidants have good compatibility with other components in the thermal sensitive coating, are not easy to volatilize and migrate, and have little effect on color and thermal sensitivity. The use of UV absorbers makes the thermal sensitive coating have strong UV absorption capacity, good stability, and is not easy to volatilize and migrate, which can effectively extend the outdoor service life of the coating and prevent discoloration, powdering and aging.

[0039] Among them, the dispersant includes sodium polyacrylate and sodium alkylbenzene sulfonate, the mass ratio of sodium polyacrylate and sodium alkylbenzene sulfonate is 1:1, sodium polyacrylate has strong electrostatic repulsion and steric hindrance, and can effectively disperse particles such as pigments and fillers, and the molecular structure of sodium alkylbenzene sulfonate contains sulfonic acid groups, which has strong hydrophilicity and dispersibility, can be quickly dissolved in water and form a stable dispersion system, and has a good dispersing effect on pigments, especially organic pigments, and has certain alkali resistance and electrolyte resistance. The combination of sodium polyacrylate and sodium alkylbenzene sulfonate makes the components such as pigments and fillers evenly dispersed in the coating to avoid agglomeration.

[0040] Among them, defoaming agents include silicone defoaming agents and mineral oil defoaming agents. The mass ratio of silicone defoaming agents to mineral oil defoaming agents is 1:1. The defoaming agent can eliminate bubbles generated during the preparation and use of the coating to ensure the quality and performance of the coating. Mineral oil defoaming agents have good defoaming and anti-foaming properties, can quickly eliminate foam in the coating, and prevent foam from being generated again. They have little effect on the performance of the coating and will not change the color, gloss and adhesion of the coating. Silicone defoaming agents have high-efficiency defoaming properties, good heat resistance, weather resistance and chemical stability, and can still maintain good defoaming effects under high temperature and harsh environments.

[0041] Among them, the color developer includes benzoic acid and salicylic acid, the mass ratio of benzoic acid and salicylic acid is 1:1, benzoic acid and salicylic acid have good thermal stability and chemical stability, and can produce more lasting color after reacting with the leuco dye, which is environmentally friendly and environmentally friendly to use.

[0042] The preparation process steps of the environmentally friendly heat-sensitive coating for triple-proof PP synthetic paper labels of the present invention include:

[0043] S1, select sodium polyacrylate and sodium alkylbenzene sulfonate with a formula ratio, dissolve the sodium polyacrylate and sodium alkylbenzene sulfonate in water to obtain a dispersed solution, and divide the dispersed solution into four parts;

[0044] S2, adding a formulated amount of titanium dioxide and zinc oxide into one of the dispersed solutions in S1, mixing and dispersing for more than 15 minutes to prepare a pigment dispersion;

[0045] S3, adding a formulated amount of titanium dioxide, zinc oxide and dimethyl silicone oil into one of the dispersed solutions in S1, mixing and dispersing for more than 40 minutes to prepare a filler dispersion;

[0046] S4, adding the formulated amount of benzenesulfonic acid amide, benzoic acid and salicylic acid into one of the dispersed solutions in S1, mixing and dispersing for more than 15 minutes to prepare a color-developing dispersed solution;

[0047] S5, adding a formula amount of hindered phenol antioxidant, ultraviolet absorber, silicone defoamer and mineral oil defoamer into one of the dispersed solutions in S1, mixing and dispersing for more than 30 minutes to prepare a defoaming dispersion;

[0048] S6, pour the pigment dispersion in S2, the filler dispersion in S3, the color development dispersion in S4, the defoaming dispersion in S5, and the formulated amount of water-based acrylic resin and polyurethane resin into the interior of the mixing device, and mix and disperse for more than 20 minutes to obtain an environmentally friendly thermal-sensitive coating;

[0049] The mixing device includes a mixing tank 1, the top of the mixing tank 1 is provided with a feed port 2, a discharge pipe 3 is fixedly installed at the bottom of the mixing tank 1, a valve 4 is fixedly installed on the discharge pipe 3, a driving motor 5 is fixedly installed on the top of the mixing tank 1, the output shaft of the driving motor 5 extends into the interior of the mixing tank 1 and is fixedly connected to a stirring rod 6 through a coupling, a connecting rod 7 is fixedly connected to the stirring rod 6, one end of the connecting rod 7 is fixedly connected to a mounting plate 8 through bolts, a rubber scraper 9 is fixedly installed on the mounting plate 8, and the rubber scraper 9 contacts the inner wall of the mixing tank 1;

[0050] The mixing tank 1 is also provided with an observation window 10 for observing the mixing and dispersion state of the heat-sensitive coating;

[0051] During the mixing and dispersing process of the thermosensitive coating, the driving motor 5 can drive the stirring rod 6 to stir the liquid inside the mixing tank 1, thereby accelerating the reaction speed between the liquids, making the reaction more complete and improving the quality of the finished product. In addition, the stirring rod 6 drives the rubber scraper 9 to scrape the inner wall of the mixing tank 1 during the stirring process, thereby preventing the liquid from adhering to the inner wall of the mixing tank 1 and causing waste.

[0052] In order to further optimize the performance of the mixing device, especially in the process of preparing environmentally friendly thermal coating bodies, we can introduce algorithms, formulas, equations and functions to accurately control the mixing process, thereby improving the uniformity and stability of the coating. The following is an algorithmic and formulaic description of the mixing device and its operation process:

[0053] Algorithm Description

[0054] Algorithm name: Environmentally friendly thermal coating mixing control algorithm

[0055] enter:

[0056] Formula amount of pigment dispersion, filler dispersion, color development dispersion and defoaming dispersion

[0057] Formula amount of water-based acrylic resin and polyurethane resin

[0058] Mixing device parameters (such as stirring speed, stirring time, etc.)

[0059] Output:

[0060] Environmentally friendly thermal coating finished products

[0061] Performance evaluation indicators of the mixing process (such as uniformity, stability, etc.)

[0062] step:

[0063] initialization:

[0064] Set the initial state of the mixing device, including stirring speed, stirring time, etc.

[0065] Load the recipe amounts for each component.

[0066] Dispersion preparation:

[0067] According to the formula amount, a pigment dispersion, a filler dispersion, a color development dispersion and a defoaming dispersion are prepared respectively.

[0068] Mixing process:

[0069] Pour each dispersion, water-based acrylic resin and polyurethane resin into a mixing tank according to the formula amount.

[0070] Start the drive motor and begin stirring.

[0071] The stirring process is controlled according to the preset values ​​of stirring speed and stirring time.

[0072] A real-time monitoring algorithm is introduced to monitor the uniformity and stability of the mixed liquid.

[0073] Performance evaluation:

[0074] During the mixing process, the homogeneity and stability of the mixed liquid are evaluated in real time.

[0075] If the preset performance indicators are not met, adjust the mixing parameters or remix.

[0076] Output finished product:

[0077] When the mixed liquid meets the preset performance index, the drive motor is turned off.

[0078] Open the discharge pipe valve to discharge the finished product of environmentally friendly thermal-sensitive coating.

[0079] Formulas and equations

[0080] Stirring speed control equation: V = f (T, M)

[0081] Wherein, V represents the stirring speed, T represents the temperature of the mixed liquid, and M represents the total mass of the mixed liquid. f is a function fitted according to experimental data, which is used to determine the stirring speed at different temperatures and masses to ensure the stirring quality, thereby improving the preparation quality of the environmentally friendly thermosensitive coating body;

[0082] Mixing uniformity evaluation formula:

[0083]

[0084] Among them, U represents the mixing uniformity, N represents the number of sampling points, and C i represents the concentration of the i-th sampling point, C avgIt represents the average concentration of the mixed liquid. The smaller the mixing uniformity, the more uniform the mixed liquid. The mixing uniformity evaluation formula can be used to understand the mixing uniformity of the prepared environmentally friendly thermal sensitive coating, so as to control the preparation quality of the environmentally friendly thermal sensitive coating body.

[0085] Stability evaluation formula:

[0086]

[0087] Among them, S represents stability, σ represents the standard deviation of the mixed solution concentration, and μ represents the average concentration of the mixed solution. The smaller the stability, the more stable the mixed solution. The stability evaluation formula can be used to evaluate the stability of the prepared environmentally friendly thermal-sensitive coating, so as to control the preparation quality of the environmentally friendly thermal-sensitive coating body.

[0088] function

[0089] Real-time monitoring function: used to monitor the uniformity and stability of the mixed liquid in real time during the mixing process. This function can obtain real-time monitoring results by calculating the above evaluation formula based on sensor data.

[0090] Stirring parameter adjustment function: According to the real-time monitoring results, adjust the stirring speed, stirring time and other parameters to improve the uniformity and stability of the mixed liquid. This function can be optimized based on historical data based on machine learning algorithms.

[0091] By introducing the above algorithms, formulas, equations and functions, the operation process of the mixing device can be controlled more accurately, thereby improving the uniformity and stability of environmentally friendly thermal coatings. At the same time, these algorithms and formulas can also provide strong support for subsequent process optimization and performance evaluation.

[0092] The above description shows and describes several preferred embodiments of the present invention, but as mentioned above, it should be understood that the present invention is not limited to the form disclosed herein, and should not be regarded as excluding other embodiments, but can be used in various other combinations, modifications and environments, and can be modified within the scope of the invention concept described herein through the above teachings or the technology or knowledge of the relevant field. Changes and variations made by those skilled in the art do not depart from the spirit and scope of the present invention, and should be within the scope of protection of the claims attached to the present invention.

Claims

1. An environmentally friendly thermal coating for triple-proof PP synthetic paper labels, characterized in that: The invention comprises an environment-friendly thermosensitive coating body, which is used for preparing a three-proof PP synthetic paper label, and the environment-friendly thermosensitive coating body is formed by mixing and spraying a plurality of ingredients, and the plurality of ingredients and weight portions include: 25-35 parts of water-based acrylic resin, 10-20 parts of polyurethane resin, 10-15 parts of environment-friendly pigment, 15-30 parts of environment-friendly filler, 8-12 parts of sensitizer, 4-8 parts of lubricant, 5-10 parts of stabilizer, 3-5 parts of dispersant, 5-10 parts of defoamer and 10-20 parts of developer.

2. The environmentally friendly heat-sensitive coating for triple-proof PP synthetic paper labels according to claim 1, characterized in that: The environmentally friendly pigment comprises titanium dioxide and zinc oxide, the mass ratio of the titanium dioxide to the zinc oxide is 4:2, and the particle sizes of the titanium dioxide and the zinc oxide are controlled within 60 μm.

3. The environmentally friendly heat-sensitive coating for triple-proof PP synthetic paper labels according to claim 2, characterized in that: The environmentally friendly filler includes calcium carbonate and silicon dioxide, and the mass ratio of the calcium carbonate to the silicon dioxide is 1:

1.

4. The environmentally friendly heat-sensitive coating for triple-proof PP synthetic paper labels according to claim 1, characterized in that: The sensitizer is benzenesulfonic acid amide.

5. The environmentally friendly heat-sensitive coating for triple-proof PP synthetic paper labels according to claim 1, characterized in that: The lubricant is dimethyl silicone oil.

6. The environmentally friendly heat-sensitive coating for triple-proof PP synthetic paper labels according to claim 1, characterized in that: The stabilizer comprises a hindered phenol antioxidant and an ultraviolet absorber, and the mass ratio of the hindered phenol antioxidant to the ultraviolet absorber is 2:

1.

7. The environmentally friendly heat-sensitive coating for triple-proof PP synthetic paper labels according to claim 1, characterized in that: The dispersant includes sodium polyacrylate and sodium alkylbenzene sulfonate, and the mass ratio of the sodium polyacrylate to the sodium alkylbenzene sulfonate is 1:

1.

8. The environmentally friendly heat-sensitive coating for triple-proof PP synthetic paper labels according to claim 1, characterized in that: The defoaming agent includes an organosilicon defoaming agent and a mineral oil defoaming agent, and the mass ratio of the organosilicon defoaming agent to the mineral oil defoaming agent is 1:

1.

9. The environmentally friendly heat-sensitive coating for triple-proof PP synthetic paper labels according to claim 1, characterized in that: The developer comprises benzoic acid and salicylic acid, and the mass ratio of the benzoic acid to the salicylic acid is 1:

1.

10. The process for preparing the environmentally friendly heat-sensitive coating for triple-proof PP synthetic paper labels according to claims 1-9, characterized in that: The specific preparation steps include: S1, select sodium polyacrylate and sodium alkylbenzene sulfonate with a formula ratio, dissolve the sodium polyacrylate and sodium alkylbenzene sulfonate in water to obtain a dispersed solution, and divide the dispersed solution into four parts; S2, adding a formulated amount of titanium dioxide and zinc oxide into one of the dispersed solutions in S1, mixing and dispersing for more than 15 minutes to prepare a pigment dispersion; S3, adding a formulated amount of titanium dioxide, zinc oxide and dimethyl silicone oil into one of the dispersed solutions in S1, mixing and dispersing for more than 40 minutes to prepare a filler dispersion; S4, adding the formulated amount of benzenesulfonic acid amide, benzoic acid and salicylic acid into one of the dispersion solutions in S1, mixing and dispersing for more than 15 minutes to prepare a color-developing dispersion; S5, adding a formula amount of hindered phenol antioxidant, ultraviolet absorber, silicone defoamer and mineral oil defoamer into one of the dispersed solutions in S1, mixing and dispersing for more than 30 minutes to prepare a defoaming dispersion; S6, pour the pigment dispersion in S2, the filler dispersion in S3, the color development dispersion in S4, the defoaming dispersion in S5, and the formulated amount of water-based acrylic resin and polyurethane resin into the interior of the mixing device, and mix and disperse for more than 20 minutes to obtain an environmentally friendly thermal-sensitive coating; The mixing device comprises a mixing tank (1), wherein the top of the mixing tank (1) is provided with a feed port (2), the bottom of the mixing tank (1) is fixedly provided with a discharge pipe (3), the discharge pipe (3) is fixedly provided with a valve (4), the top of the mixing tank (1) is fixedly provided with a drive motor (5), the output shaft of the drive motor (5) extends into the interior of the mixing tank (1) and is fixedly connected to a stirring rod (6) via a coupling, the stirring rod (6) is fixedly connected to a connecting rod (7), one end of the connecting rod (7) is fixedly connected to a mounting plate (8) via bolts, a rubber scraper (9) is fixedly provided on the mounting plate (8), and the rubber scraper (9) contacts the inner wall of the mixing tank (1).

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