Ethanol-tolerant photo-thermal double-control color-changing water-based ink and preparation method thereof

Abstract

The invention discloses ethanol-resistant photo-thermal double-control color-changing water-based ink and a preparation method thereof. The ethanol-resistant photo-thermal double-control color-changing water-based ink comprises the following components in parts by weight: 10-20 parts of photo-thermal color-changing microcapsules, 10-20 parts of thermosensitive color-changing microcapsules, 30-50 parts of water-based acrylic resin, 5-10 parts of an ethanol-resistant additive, 2-5 parts of a dispersing agent, 1-3 parts of a defoaming agent, 1-3 parts of a thickening agent, 1-3 parts of a flatting agent and 20-40 parts of deionized water. The organic silicon modified polyurethane is added as an ethanol tolerance additive, and silicon-oxygen bonds and carbamate bonds in molecules of the organic silicon modified polyurethane can interact with the water-based acrylic resin to construct an ethanol-tolerant network structure, so that the ink can effectively resist the erosion of ethanol when being in contact with the ethanol; the photothermal color-changing microcapsule with spiropyrane compounds as a color-changing core material and melamine-formaldehyde resin as a wall material is adopted, crystal violet lactone, p-toluenesulfonic acid and the like are used as a core, the color of the ink can be accurately and rapidly changed under different illumination intensity and temperature conditions, and the stability is good after multiple color-changing cycles.

Description

Technical Field

[0001] The invention belongs to the technical field of concrete preparation, and in particular relates to an ethanol-resistant light-heat dual-control color-changing water-based ink and a preparation method thereof. Background Art

[0002] In today's packaging and printing industry, the demand for special effect inks is growing. Photothermal dual-control color-changing inks can present different colors according to changes in light intensity and temperature, giving the product a unique visual charm and interactivity.

[0003] In the prior art, due to the lack of effective design for ethanol tolerance, the performance of the ink is seriously damaged after contacting ethanol. Most existing ink systems do not use additives with special chemical structures to enhance ethanol resistance. When the main film-forming substance in the ink, such as traditional water-based acrylic resin, faces ethanol alone, its molecular structure is easily affected by the chemical action of ethanol. As a polar organic solvent, ethanol can destroy the weak interaction force between resin molecules, causing the structure of the resin film to gradually loosen; at the same time, when dealing with ethanol erosion, the existing ink lacks an effective protective network structure inside. After contacting ethanol, ethanol molecules can quickly penetrate into the interior of the ink and directly attack core components such as photothermochromic microcapsules and thermochromic microcapsules, which will not only destroy the wall material structure of the microcapsules, causing the core material to leak, but also interfere with the chemical reaction process of the color-changing substance, thereby causing serious fading of the ink.

[0004] To this end, we propose an ethanol-resistant light-heat dual-control color-changing water-based ink and a preparation method thereof to solve the problems mentioned in the above background technology. Summary of the invention

[0005] The object of the present invention is to provide an ethanol-resistant light-heat dual-control color-changing water-based ink and a preparation method thereof, so as to solve the problems raised in the above-mentioned background technology.

[0006] To achieve the above-mentioned purpose, the present invention provides the following technical scheme: an ethanol-resistant photothermal dual-control color-changing water-based ink, comprising, by weight, 10-20 parts of photothermal color-changing microcapsules, 10-20 parts of thermosensitive color-changing microcapsules, 30-50 parts of water-based acrylic resin, 5-10 parts of ethanol-tolerant additives, 2-5 parts of dispersants, 1-3 parts of defoaming agents, 1-3 parts of thickeners, 1-3 parts of leveling agents, and 20-40 parts of deionized water.

[0007] Preferably, by weight, it includes 15 parts of photothermochromic microcapsules, 16 parts of thermochromic microcapsules, 40 parts of water-based acrylic resin, 7 parts of ethanol tolerance additives, 3 parts of dispersants, 2 parts of defoamers, 1 part of thickeners, 2 parts of leveling agents, and 30 parts of deionized water.

[0008] Preferably, the photothermochromic microcapsules use spiropyran compounds as the color-changing core material and melamine-formaldehyde resin as the wall material.

[0009] Preferably, the core of the thermochromic microcapsule is a mixture of a thermochromic dye, a developer and a solvent, such as crystal violet lactone, p-toluenesulfonic acid, etc., and the shell is also made of a polymer material, such as polystyrene.

[0010] Preferably, the ethanol-resistant additive is an organosilicon-modified polyurethane, the molecule of which contains silicon-oxygen bonds and urethane bonds, and interacts with the water-based acrylic resin to construct an ethanol-resistant network structure.

[0011] Preferably, the dispersant is a polycarboxylate dispersant, which can effectively disperse solid particles such as photothermochromic microcapsules.

[0012] Preferably, the defoaming agent is a silicone defoaming agent.

[0013] Preferably, the leveling agent is a fluorocarbon leveling agent.

[0014] The present invention also provides a method for preparing an ethanol-resistant light-heat dual-control color-changing water-based ink, which specifically comprises the following steps:

[0015] S1, adding photothermochromic microcapsules and thermochromic microcapsules into deionized water, stirring at a speed of 300 r / min for 30 minutes to obtain a microcapsule dispersion;

[0016] S2. Add a polycarboxylate dispersant to the microcapsule dispersion and continue stirring at a speed of 450 r / min for 20 minutes to evenly disperse the photothermochromic microcapsules;

[0017] S3, adding water-based acrylic resin to the microcapsule dispersion, stirring at a speed of 500 r / min for 30 minutes to mix evenly;

[0018] S4, add ethanol tolerance additive and silicone defoamer in sequence, and stir for 20 minutes until uniform;

[0019] S5. Finally, hydroxyethyl cellulose and a leveling agent are added as thickeners to adjust the ink viscosity to a suitable range, thereby obtaining an ethanol-resistant, light-heat-controlled, color-changing water-based ink.

[0020] Preferably, in step S4, the ethanol tolerance additive and the silicone defoaming agent are stirred at a speed of 350 r / min for 20 minutes until they are uniform.

[0021] Compared with the prior art, the present invention has the following beneficial effects:

[0022] (1) By adding silicone-modified polyurethane as an ethanol-resistant additive, the siloxane bonds and urethane bonds in its molecules can interact with water-based acrylic resin to build an ethanol-resistant network structure. This unique structure enables the ink to effectively resist the erosion of ethanol when it comes into contact with ethanol, maintaining the integrity and color-changing properties of the ink. Even if it comes into contact with high-concentration ethanol for a long time, the ink will not fade, dissolve or change color abnormally, which greatly broadens the application scenarios of the ink and allows it to be used in printing fields that are easily exposed to ethanol, such as wine packaging and pharmaceutical product labels.

[0023] (2) Photothermal color-changing microcapsules using spiropyran compounds as the color-changing core material and melamine-formaldehyde resin as the wall material, as well as thermochromic microcapsules with crystal violet lactone, p-toluenesulfonic acid and other components as the core and polystyrene as the shell, with reasonable preparation process and proportion of each component, can accurately and rapidly change color under different light intensity and temperature conditions, and have good stability after multiple color change cycles. Whether under direct sunlight or when the temperature fluctuates slightly, it can show obvious and stable color changes, meeting the application requirements of smart packaging, anti-counterfeiting labels, etc. that have high requirements for photothermal dual-control color-changing performance. DETAILED DESCRIPTION

[0024] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0025] The invention provides an ethanol-resistant photothermal dual-control color-changing water-based ink, which comprises, by weight, 10-20 parts of photothermal color-changing microcapsules, 10-20 parts of thermosensitive color-changing microcapsules, 30-50 parts of water-based acrylic resin, 5-10 parts of ethanol-tolerant additives, 2-5 parts of dispersants, 1-3 parts of defoamers, 1-3 parts of thickeners, 1-3 parts of leveling agents, and 20-40 parts of deionized water.

[0026] In parts by weight, the composition includes 15 parts of photothermochromic microcapsules, 16 parts of thermochromic microcapsules, 40 parts of water-based acrylic resin, 7 parts of ethanol tolerance additives, 3 parts of dispersants, 2 parts of defoamers, 1 part of thickeners, 2 parts of leveling agents, and 30 parts of deionized water.

[0027] Photothermochromic microcapsules: Spiropyran compounds are used as the color-changing core material, and melamine-formaldehyde resin is used as the wall material; Spiropyran compounds have unique photochromic properties. Under light of different wavelengths, their molecular structure will undergo reversible changes, resulting in color changes; Melamine-formaldehyde resin wall material can effectively protect the core material and improve the stability and chemical resistance of the microcapsules;

[0028] Thermochromic microcapsules: The core is a mixture of thermochromic dyes, color developers and solvents, such as crystal violet lactone, p-toluenesulfonic acid, etc. The shell is also made of polymer materials, such as polystyrene. Thermochromic microcapsules can change color according to temperature changes, and work synergistically with photochromic microcapsules to achieve the effect of photothermal dual-control color change.

[0029] Ethanol tolerance additive: It is a silicone-modified polyurethane with silicon-oxygen bonds and urethane bonds in its molecules; these chemical bonds can interact with water-based acrylic resins to build an ethanol-resistant network structure in the ink system, thereby significantly improving the ethanol resistance of the ink;

[0030] Dispersant: Use polycarboxylate dispersants; polycarboxylate dispersants have good dispersing properties and can effectively reduce the surface tension between solid particles such as photothermochromic microcapsules and thermochromic microcapsules, making them evenly dispersed in the ink system and preventing particle agglomeration and precipitation;

[0031] Defoamer: Use silicone defoamer; silicone defoamers have the characteristics of fast defoaming speed and long anti-foaming time, which can effectively eliminate bubbles generated during the ink production process to ensure the uniformity of the ink and the printing quality;

[0032] Leveling agent: Use fluorocarbon leveling agent; fluorocarbon leveling agent can reduce the surface tension of ink, improve the fluidity and leveling of ink, make the surface of printed ink smoother, and reduce printing defects such as orange peel and shrinkage.

[0033] Thickener: Hydroxyethyl cellulose is selected in the present invention to adjust the viscosity of the ink so that it meets the requirements of different printing processes.

[0034] The photothermochromic microcapsules use spiropyran compounds as color-changing core materials and melamine-formaldehyde resin as wall materials.

[0035] The core of the thermochromic microcapsule is a mixture of thermochromic dye, developer and solvent, such as crystal violet lactone, p-toluenesulfonic acid, etc., and the shell is also made of polymer material, such as polystyrene.

[0036] The ethanol tolerance additive is an organosilicon-modified polyurethane, the molecule of which contains a silicon-oxygen bond and a carbamate bond, and interacts with the water-based acrylic resin to construct an ethanol-resistant network structure.

[0037] The dispersant is a polycarboxylate dispersant, which can effectively disperse solid particles such as photothermochromic microcapsules.

[0038] The defoaming agent is a silicone defoaming agent.

[0039] The leveling agent used is a fluorocarbon leveling agent.

[0040] The present invention also provides a method for preparing an ethanol-resistant light-heat dual-control color-changing water-based ink, which specifically comprises the following steps:

[0041] S1, adding photothermochromic microcapsules and thermochromic microcapsules into deionized water, stirring at a speed of 300 r / min for 30 minutes to obtain a microcapsule dispersion;

[0042] S2. Add a polycarboxylate dispersant to the microcapsule dispersion and continue stirring at a speed of 450 r / min for 20 minutes to evenly disperse the photothermochromic microcapsules;

[0043] S3, adding water-based acrylic resin to the microcapsule dispersion, stirring at a speed of 500 r / min for 30 minutes to mix evenly;

[0044] S4, add ethanol tolerance additive and silicone defoamer in sequence, and stir for 20 minutes until uniform;

[0045] S5. Finally, hydroxyethyl cellulose and a leveling agent are added as thickeners to adjust the ink viscosity to a suitable range, thereby obtaining an ethanol-resistant, light-heat-controlled, color-changing water-based ink.

[0046] In the step S4, the ethanol tolerance additive and the silicone defoamer are stirred at a speed of 350 r / min for 20 minutes until they are uniform.

[0047] Experimental group: using ink containing ethanol tolerance additive;

[0048] Control group: Common water-based inks on the market, which do not have the light-heat dual-control color-changing function and ethanol resistance, were selected as basic comparison samples;

[0049] (I) Photothermochromic performance test

[0050] Photochromism: Use a silk screen to print each ink evenly on white coated paper to form an ink film with a thickness of about 20μm. Use a 100W ultraviolet lamp to irradiate the ink film for 15 minutes at a vertical distance of 15cm. Before irradiation, every 5 minutes during irradiation, and after irradiation, use a high-precision colorimeter to measure the color of the ink film and record the changes in color difference values ​​to evaluate the response speed and stability of photochromism.

[0051] Thermochromic: Place the paper printed with ink on a hot plate with precise temperature control, and heat it from 25°C to 80°C at a rate of 5°C / min. During the heating process, measure the color of the ink film with a colorimeter every 5°C, record the color change starting temperature, color change range and color difference value changes, and judge the thermochromic performance;

[0052] (II) Ethanol resistance test

[0053] Immersion test: Print the ink evenly on a glass sheet. After it is completely dry, immerse the glass sheet in a 95% ethanol solution. Take out the glass sheet every 24 hours and observe with a magnifying glass in a bright environment whether the ink film is dissolved, faded, peeled or fallen off. Record the time when the first obvious damage occurs.

[0054] Wipe test: Dip a cotton swab in anhydrous ethanol and wipe the surface of the paper printed with ink back and forth 50 times with constant pressure. Then observe the surface condition of the ink film under a standard light source and rate it based on whether it has faded or the degree of wear (1-5 levels, 1 for no change and 5 for severe damage).

[0055] (III) Stability test

[0056] Storage stability: seal the ink sample in a brown glass bottle and place it in an environmental box with constant temperature (25°C) and constant humidity (relative humidity 50%). Take out the sample every month and observe the ink with the naked eye to see if there is stratification or precipitation. Use a rotational viscometer to measure the viscosity change and record the longest storage time that the ink can maintain normal use status.

[0057] Weathering stability: Place the printed sample in a simulated sunlight aging test chamber and test it according to standard test conditions (light intensity 550W / m 2 , temperature 45°C, relative humidity 70%), take out the sample every 50 hours, compare the color and glossiness of the sample with the initial state, and evaluate the weathering stability;

[0058] (IV) Printing adaptability test

[0059] Viscosity test: At 25°C, use a rotational viscometer to measure the viscosity of the ink according to the standard test method, and compare whether the viscosity of different inks under the same printing process meets the ideal range (the general printing ink viscosity range is 20-50mPa·s);

[0060] Leveling test: drop 0.5mL of ink on a horizontal glass sheet, let it stand for 10 minutes, and then observe the surface flatness after the ink naturally leveled. Use a leveling meter to measure the leveling diameter. The larger the leveling diameter, the better the leveling property.

[0061] Adhesion fastness test: According to GB / T9286-1998 "Scratching test for paint and varnish film", use a scribing tool to scratch a 1mm×1mm square on the sample printed with ink, then stick it with 3M tape and quickly tear it off, observe the ink shedding in the grid to evaluate the adhesion fastness (0 level means no shedding, 5 level means severe shedding);

[0062] Table 1 is a comparative experimental result table of the photothermal color change performance test, ethanol resistance performance test, stability test and printing adaptability test of the ethanol-resistant photothermal dual-control color-changing water-based ink of the present invention and the traditional water-based ink:

[0063]

[0064]

[0065] Experimental results analysis:

[0066] Photochromic performance: In terms of photochromism, the color difference values ​​of the ink of the present invention after irradiation for 5 minutes and 15 minutes are significantly higher than that of the traditional water-based ink (no discoloration), indicating that its photochromic response is rapid and the effect is obvious. In terms of thermochromism, the discoloration starting temperature is appropriate and the discoloration range is reasonable, showing good thermochromic performance and being able to meet the requirements of discoloration temperature in different scenarios.

[0067] Ethanol resistance: In the ethanol immersion resistance test, the ink of the present invention can keep the ink film intact for a long time, far exceeding the traditional water-based ink. The wipe test rating is 1, indicating that it has excellent ethanol wiping resistance. This is due to the ethanol-resistant network structure constructed by silicone-modified polyurethane and water-based acrylic resin, which effectively resists the erosion of ethanol.

[0068] Stability: In terms of storage stability, the ink of the present invention can be stored for more than 6 months without obvious stratification and precipitation, which is much longer than traditional water-based inks. In terms of weathering stability, the color difference value after aging for 100 hours is small, indicating that it can maintain good color stability in complex environments such as outdoors, thereby extending the service life of ink products.

[0069] Printing adaptability: The viscosity of the ink of the present invention is in the ideal printing range, the leveling diameter is large, the adhesion fastness rating is 0, and the overall performance is better than that of traditional water-based inks. It can ensure that in the actual printing process, the ink is evenly distributed and firmly adheres to the printing substrate, and the printing effect is clear and beautiful.

[0070] Specific use:

[0071] Add photothermochromic microcapsules and thermochromic microcapsules into deionized water in corresponding proportions and stir at 300r / min for 30 minutes. This stirring speed and time can make the microcapsules disperse preliminarily in the water, and use the shear force of the water flow to break up the microcapsule aggregates to form a more uniform suspension. Since the microcapsules have a certain specific gravity, they will be affected by both gravity and water flow during the stirring process. After 30 minutes of stirring, it can basically ensure that the microcapsules are evenly dispersed in the water, providing a good foundation for the subsequent role of the dispersant.

[0072] Add polycarboxylate dispersant to the microcapsule dispersion and continue stirring at a speed of 450r / min for 20 minutes. The purpose of increasing the stirring speed is to enhance the interaction between the dispersant and the microcapsules. In this process, the dispersant molecules are rapidly adsorbed on the surface of the microcapsules, the lipophilic hydrocarbon groups are combined with the surface of the microcapsules, and the hydrophilic carboxyl groups extend outward. The higher stirring speed helps the dispersant molecules to be evenly distributed on the surface of the microcapsules. At the same time, a stronger shear force is used to further refine the dispersion state of the microcapsules, so that the solid particles such as the photothermochromic microcapsules are evenly dispersed in the deionized water under the action of the dispersant, forming a stable dispersion system, reducing the particle agglomeration phenomenon, and ensuring the uniformity of the ink quality;

[0073] Add water-based acrylic resin to the microcapsule dispersion and stir at a speed of 500 r / min for 30 minutes. This stirring speed can fully mix the water-based acrylic resin and the microcapsule dispersion. During the stirring process, the acrylic resin molecules are gradually wrapped on the surface of the microcapsules and interact with the dispersant molecules and deionized water. After 30 minutes of stirring, the acrylic resin can be evenly dispersed in the entire system, laying a foundation for the subsequent construction of the film-forming structure of the ink, ensuring that the ink can form a continuous, complete and good-performance film after drying;

[0074] Add ethanol-tolerant additives and silicone defoamers in sequence, and stir at a speed of 350r / min for 20 minutes until uniform. This stirring speed can not only ensure that the ethanol-tolerant additives react fully with the water-based acrylic resin to build an ethanol-resistant network structure, but also make the defoamer evenly dispersed in the system to play a defoaming role. The active groups in the ethanol-tolerant additives and the acrylic resin molecules gradually undergo chemical bonding and physical entanglement during the stirring process to form a stable network structure; the silicone defoamer can slowly migrate to the bubble surface at a lower stirring speed, effectively eliminate the bubbles in the ink, avoid the re-introduction of too many bubbles due to high-speed stirring, and ensure the stability and uniformity of the ink system;

[0075] Finally, add thickener hydroxyethyl cellulose and leveling agent, and adjust the ink viscosity to the appropriate range by stirring to obtain ethanol-resistant light and heat dual-control color-changing water-based ink. During the stirring process, hydroxyethyl cellulose gradually swells, and the molecular chains entangle with each other, increasing the viscosity of the ink; the fluorocarbon leveling agent migrates to the ink surface to improve the surface tension and leveling performance of the ink. The operator can adjust the stirring time and the amount of thickener and leveling agent added by observing and testing the viscosity of the ink (such as measuring with a viscometer) according to the requirements of different printing processes, so that the ink achieves the best printability, ensures a smooth printing process, and ensures excellent quality of printed products.

[0076] Finally, it should be noted that the above is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, it is still possible for those skilled in the art to modify the technical solutions described in the aforementioned embodiments or to make equivalent substitutions for some of the technical features therein. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. An ethanol-resistant light-heat dual-control color-changing water-based ink, characterized in that: Calculated by weight, it includes 10-20 parts of photothermochromic microcapsules, 10-20 parts of thermochromic microcapsules, 30-50 parts of water-based acrylic resin, 5-10 parts of ethanol tolerance additives, 2-5 parts of dispersants, 1-3 parts of defoamers, 1-3 parts of thickeners, 1-3 parts of leveling agents, and the balance is ionized water.

2. The ethanol-resistant light-heat dual-control color-changing water-based ink according to claim 1, characterized in that: In parts by weight, the composition includes 15 parts of photothermochromic microcapsules, 16 parts of thermochromic microcapsules, 40 parts of water-based acrylic resin, 7 parts of ethanol tolerance additives, 3 parts of dispersants, 2 parts of defoamers, 1 part of thickeners, 2 parts of leveling agents, and 30 parts of deionized water.

3. The ethanol-resistant light-heat dual-control color-changing water-based ink according to claim 1, characterized in that: The photothermochromic microcapsules use spiropyran compounds as color-changing core materials and melamine-formaldehyde resin as wall materials.

4. The ethanol-resistant light-heat dual-control color-changing water-based ink according to claim 1, characterized in that: The core of the thermochromic microcapsule is a mixture of thermochromic dye, developer and solvent, and the shell is also made of polymer material.

5. The ethanol-resistant light-heat dual-control color-changing water-based ink according to claim 1, characterized in that: The ethanol tolerance additive is an organosilicon-modified polyurethane, the molecule of which contains a silicon-oxygen bond and a carbamate bond, and interacts with the water-based acrylic resin to construct an ethanol-resistant network structure.

6. The ethanol-resistant light-heat dual-control color-changing water-based ink according to claim 5, characterized in that: The dispersant is a polycarboxylate dispersant or an effective disperser of photothermochromic microcapsules.

7. The ethanol-resistant light-heat dual-control color-changing water-based ink according to claim 1, characterized in that: The defoaming agent is a silicone defoaming agent.

8. The ethanol-resistant light-heat dual-control color-changing water-based ink according to claim 1, characterized in that: The leveling agent used is a fluorocarbon leveling agent.

9. A method for preparing an ethanol-resistant light-heat dual-control color-changing water-based ink according to any one of claims 1 to 8, characterized in that: The specific steps include: S1, adding photothermochromic microcapsules and thermochromic microcapsules into deionized water, stirring at a speed of 300 r / min for 30 minutes to obtain a microcapsule dispersion; S2. Add a polycarboxylate dispersant to the microcapsule dispersion and continue stirring at a speed of 450 r / min for 20 minutes to evenly disperse the photothermochromic microcapsules; S3, adding water-based acrylic resin to the microcapsule dispersion, stirring at a speed of 500 r / min for 30 minutes to mix evenly; S4, add ethanol tolerance additive and silicone defoamer in sequence, and stir for 20 minutes until uniform; S5. Finally, hydroxyethyl cellulose and a leveling agent are added as thickeners to adjust the ink viscosity to a suitable range, thereby obtaining an ethanol-resistant, light-heat-controlled, color-changing water-based ink.

10. The method for preparing the ethanol-resistant light-heat dual-control color-changing water-based ink according to claim 9, characterized in that: In the step S4, the ethanol tolerance additive and the silicone defoamer are stirred at a speed of 350 r / min for 20 minutes until they are uniform.

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