Intaglio pearlescent ink and method of making the same

Abstract

The application discloses a kind of gravure pearlescent inks, the gravure pearlescent ink is composed of substrate resin system, environmentally friendly solvent system, pearlescent pigment and adjuvant;Wherein, the substrate resin system is by acrylic modified polyurethane and nitrocellulose mixed into;The environmentally friendly solvent system is by n-propyl acetate, isophorone and gamma-butyrolactone mixed into;The adjuvant is by leveling agent, defoaming agent and light stabilizer composition.The application also discloses the preparation method of the gravure pearlescent ink, and the specific steps include pre-dispersion stage, resin dissolving stage, fine grinding stage and post-adjustment stage.The gravure pearlescent ink provided by the application not only has excellent mechanical properties but also has good optical performance.The gravure pearlescent ink provided by the application has excellent antibacterial performance.The preparation method of the gravure pearlescent ink provided by the application also has the advantages of simple process, mild conditions, good repeatability and being conducive to industrialization promotion.

Description

Technical Field

[0001] This invention belongs to the field of ink materials, and in particular relates to a gravure pearlescent ink and its preparation method. Background Technology

[0002] With the continuous development of the social economy, the printing industry has deeply integrated into people's daily lives and become an indispensable part of all walks of life. It can be said that the development level of the printing industry has become one of the important indicators for measuring the modernization level of a country. As a key material in the printing industry, the quality of ink directly affects the quality of printed products. As people's requirements for the quality of printed products continue to increase, the quality of ink must also be improved accordingly. Therefore, using high-tech means to promote the development of the ink industry has become an inevitable choice to adapt to the development of the times. In recent years, the trend of high-tech inks has become increasingly obvious, and various new inks with special properties have emerged. Among them, pearlescent inks have received widespread attention from the market due to their unique decorative effect and wide range of applications. Pearlescent inks can be printed not only on paper but also on plastic materials. In the field of high-end cigarette, alcohol and cosmetic packaging, the application of pearlescent inks is particularly prominent. It can not only significantly improve the aesthetics of packaging but also improve the overall grade of the product, thus attracting the favor of many enterprises (Li Lianjun. Rational application of pearlescent powder in gravure printing [J]. Printing Technology, 2002, 31-32.).

[0003] Despite the numerous advantages of pearlescent inks, ordinary pearlescent inks still face several pressing problems. Firstly, the ink layer of pearlescent inks is relatively thick, resulting in a slower drying speed compared to ordinary inks. Secondly, excessively coarse pearlescent pigment particles increase ink consumption and leave behind residues that are difficult to separate, leading to ink waste. Thirdly, the adhesion of printed pearlescent inks is poor, easily causing pearlescent powder to detach and affecting the aesthetics of the printed matter. Finally, ordinary pearlescent inks lack antibacterial and bacteriostatic properties, making printed matter prone to mold growth. Therefore, how to utilize high-tech methods to compound and modify ordinary pearlescent inks has always been a hot topic in the ink field (Cui Feng, Wang Zhan. Analysis and Development Trends of Flexible Printed Electronics Technology [J]. Integrated Circuits, 2019, 36(2): 32-35). In view of this, this patent application is hereby filed. Summary of the Invention

[0004] The purpose of this invention is to provide a gravure pearlescent ink and its preparation method.

[0005] To achieve the above objectives, the solution of the present invention is:

[0006] A gravure pearlescent ink, comprising a substrate resin system, an environmentally friendly solvent system, pearlescent pigments, and additives; wherein the substrate resin system is a mixture of acrylic-modified polyurethane and nitrocellulose; the environmentally friendly solvent system is a mixture of n-propyl acetate, isophorone, and γ-butyrolactone; the additives are leveling agents, defoamers, and light stabilizers; and the pearlescent pigment is TiO2 / SiO2 modified graphite flakes, wherein the TiO2 / SiO2 modified graphite flakes contain an alternating TiO2 / SiO2 multilayer film structure.

[0007] Preferably, the TiO2 / SiO2 alternating multilayer film structure comprises: 5-15 alternating deposited metal oxide layers, each with a thickness of 10-50 nm; an outermost SiO2 protective layer with a thickness accounting for 10-20% of the total film thickness; and 0.5-5 wt% of a silane coupling agent grafted onto the film surface, wherein the coupling agent is selected from at least one of KH-550 and KH-570.

[0008] Preferably, the acrylic-modified polyurethane and nitrocellulose in the substrate resin system are in a mass ratio of 3:1 to 1:3.

[0009] Preferably, the additive comprises: 0.1-2 wt% of an organosilicon leveling agent, 0.05-1 wt% of a polyether-modified silicone oil defoamer, 0.1-3 wt% of a benzotriazole UV absorber, and 0.05-0.5 wt% of a hindered amine light stabilizer.

[0010] Preferably, it further comprises: 0.5-5 wt% of nano-alumina dispersion, 0.5-1 wt% of antibacterial agent dispersion, and 1-10 wt% of thixotropic agent; wherein the thixotropic agent is selected from at least one of organobentonite or fumed silica.

[0011] The aforementioned method for preparing gravure pearlescent ink specifically includes the following steps:

[0012] (1) Pre-dispersion stage: Pearl pigment and part of solvent are subjected to high-speed shear dispersion at a shear rate of 5000-15000 rpm to obtain pearl pigment dispersion;

[0013] (2) Resin dissolution stage: The substrate resin system and the remaining solvent are added to the pearl pigment dispersion prepared in step (1), and then the resulting mixture is heated and stirred until the viscosity is stable to obtain the pearl ink mixture.

[0014] (3) Fine grinding stage: The pearlescent ink mixture obtained in step (2) is placed into a three-roll mill for 3-5 passes of grinding, and the grinding gap is controlled to be 5-50μm to prepare the pearlescent ink grinding material;

[0015] (4) Post-adjustment stage: Add additives to the pearlescent ink grinding material obtained in step (3) and disperse it evenly to prepare the pearlescent ink.

[0016] Preferably, the pre-dispersion stage includes the following stages:

[0017] First stage: Disperse at 5000-8000 rpm for 10-30 minutes at 50-60℃;

[0018] Second stage: After cooling to 30-40℃, add the surface treatment agent and disperse at 7000rpm for 15-45min;

[0019] Third stage: Filter through a 325-mesh sieve, with a filter residue rate of ≤0.1%.

[0020] Preferably, the heating and stirring temperature during the resin dissolution stage is 50-80℃.

[0021] Preferably, the process parameters for the fine grinding stage are:

[0022] First pass: Roller spacing 30-50μm, roller temperature 25-35℃;

[0023] Second pass: Roller spacing 15-30μm, roller temperature 35-45℃;

[0024] Third pass: Roller spacing 5-15μm, roller temperature 45-55℃.

[0025] Preferably, the dispersion treatment in the post-adjustment stage is ultrasonic treatment; the treatment time is 30-120 min, and the ultrasonic frequency is 20-40 kHz.

[0026] The principle of the gravure pearlescent ink and its preparation method provided by this invention is as follows:

[0027] The gravure pearlescent ink provided by this invention uses modified graphite flakes as the pearlescent pigment. This fully utilizes the high mechanical strength and stability of graphite flakes, resulting in good adhesion and abrasion resistance after printing. Furthermore, the mechanical strength and stability of the modified graphite flakes are further enhanced. Specifically, this invention uses titanium dioxide and silicon dioxide to modify the graphite flake substrate. Titanium dioxide has a high refractive index (approximately 2.7), enabling the formation of multiple interference films on the graphite flake surface, thus producing a unique pearlescent effect. This pearlescent effect is widely used in high-end coatings, plastics, and cosmetics to enhance the visual appeal of products. By controlling the coating thickness of titanium dioxide, the color of the pearlescent pigment can be adjusted from white to various metallic hues to meet different application requirements. Silicon dioxide has high hardness, which can improve the surface hardness of the graphite flakes, enhancing their abrasion resistance and scratch resistance. Therefore, silicon dioxide can enhance the mechanical stability of the graphite flakes, making them less prone to breakage or deformation during processing and use. Furthermore, silica possesses excellent dispersibility, improving the dispersion of graphite flakes in various media and resulting in a more uniform distribution in coatings, inks, and other applications. Titanium dioxide primarily enhances optical properties and chemical stability, while silica mainly improves mechanical properties and dispersibility; their synergistic effect significantly enhances the overall performance of graphite flakes, expanding their application range. The added ternary composite antibacterial agent, consisting of silver-loaded titanium dioxide, zinc oxide / chitosan complex, and quaternary ammonium salt-modified montmorillonite, can act as a photocatalytic antibacterial agent to enhance the antibacterial properties of the ink; therefore, the prepared ink not only exhibits excellent mechanical properties but also good antibacterial activity.

[0028] The beneficial effects of the gravure pearlescent ink and its preparation method provided by this invention are as follows:

[0029] (1) The gravure pearlescent ink provided by the present invention not only has excellent mechanical properties but also good optical properties.

[0030] (2) The gravure pearlescent ink provided by the present invention has excellent antibacterial properties, with an antibacterial rate of over 98% against both Escherichia coli and Staphylococcus aureus.

[0031] (3) The method for preparing gravure pearlescent ink provided by the present invention also has the advantages of simple process, mild conditions, good repeatability and industrial promotion, providing a new method for preparing gravure pearlescent ink and opening up new ideas. Detailed Implementation

[0032] The present invention will be further described in detail below with reference to embodiments. It should also be understood that the following embodiments are only for further illustration of the present invention and should not be construed as limiting the scope of protection of the present invention. The specific mass, reaction time, temperature, process parameters, etc., in the examples are merely examples within a suitable range. Any non-essential improvements and adjustments made by those skilled in the art based on the above description of the present invention are within the scope of protection of the present invention.

[0033] Unless otherwise specified, all reagents used are commercially available and were not further purified before use.

[0034] The preparation steps of the acrylic-modified polyurethane used in some embodiments of this invention are as follows:

[0035] 83.12 g of polypropylene glycol-1000 (PPG-1000), 6.447 g of polydimethylsiloxane (PDMSOH), 0.04 g of bismuth neodecanoate, and 20 mL of acetone were added to a 1 L four-necked flask and subjected to dehydration under reduced pressure. Then, 55.58 g of pre-mixed isophorone diisocyanate (IPDI) and 250 mL of acetone solution were slowly added dropwise to the system in the flask using a constant-pressure dropping funnel under stirring. After the addition was complete, the system was heated to 75 °C and maintained at this temperature for 2 hours. Next, 16.77 g of dimethylolpropionic acid (DMPA) and 0.04 g of bismuth neodecanoate were added sequentially, and the reaction continued for 1 hour. Finally, a mixture of p-hydroxyanisole (MEHQ) / acrylomorpholine (ACMO) polymerization inhibitors (1.00 g of MEHQ dissolved in 1.0 g of ACMO) was added dropwise. Continue the reaction at 75°C for 1 hour (if the viscosity of the system is too high, add an appropriate amount of solvent to adjust). Maintain the constant temperature of 75°C and slowly add 49.72 g of pentaerythritol triacrylate (PET3A) dropwise through a constant pressure dropping funnel. After the addition is complete, maintain the constant temperature for 2 hours. Subsequently, cool the system to 50-60°C, add 4.00 g of anhydrous ethanol, and stir at a constant temperature for 30 minutes. Finally, cool to room temperature and discharge to obtain the target product.

[0036] The preparation steps of the antibacterial agent used in some embodiments of the present invention are as follows:

[0037] (1) Preparation of silver-loaded titanium dioxide: 50 mL of tetrabutyl titanate and 100 mL of anhydrous ethanol were mixed and stirred at 300 r / min on a magnetic stirrer to form solution A. 2 g of silver nitrate was weighed and dissolved in 50 mL of deionized water to form solution B. Under vigorous stirring, solution B was slowly added dropwise to solution A at a rate of 2 mL per minute. After the addition was complete, stirring was continued for 30 min. Then 5 mL of glacial acetic acid was added to adjust the pH to 3-4 to form a sol. The sol was transferred to a microwave reaction vessel for thermal aging. The microwave reaction was carried out at 80 °C for 2 h with a microwave power of 450 W. After the reaction was completed, the product was naturally cooled to room temperature. The product was transferred to a centrifuge tube and centrifuged at 5000 r / min for 10 min. It was washed three times each with 25 mL of deionized water and 25 mL of anhydrous ethanol, and then dried in a vacuum drying oven at 60 °C for 12 h to obtain silver-loaded titanium dioxide.

[0038] (2) Preparation of zinc oxide / chitosan complex: 5g of chitosan was dissolved in 100mL of acetic acid solution and stirred until homogeneous to form a chitosan solution. 0.1g of zinc nitrate was dissolved in 10mL of deionized water to form a zinc nitrate solution. Under stirring, the zinc nitrate solution was slowly added dropwise to the chitosan solution, while simultaneously adding 5% ammonia solution to adjust the pH of the system to 9, so that the zinc ions in the solution react with the chitosan to form a precipitate. The precipitate was filtered and washed three times with 25mL of deionized water, and then dried in a vacuum drying oven to obtain the zinc oxide / chitosan complex.

[0039] (3) Disperse 10g of montmorillonite in 200mL of deionized water to form a montmorillonite suspension. Dissolve 1g of hexadecyltrimethylammonium bromide in 50mL of deionized water to form a quaternary ammonium salt solution. Under stirring, slowly add the quaternary ammonium salt solution to the montmorillonite suspension and stir the reaction at room temperature for 1h to allow ion exchange between the quaternary ammonium salt cations and the cations between the montmorillonite layers. After the reaction is complete, centrifuge the product, wash it three times with 50mL of deionized water to remove unreacted quaternary ammonium salt, and then dry it in a vacuum drying oven to obtain quaternary ammonium salt modified montmorillonite;

[0040] (4) Add 1g of silver-loaded titanium dioxide prepared in step (1), 3g of zinc oxide / chitosan complex prepared in step (2), and 6g of quaternary ammonium salt modified montmorillonite prepared in step (3) to 100mL of ethanol; ultrasonically disperse the resulting mixture for 30 minutes at a power of 200W and a frequency of 40kHz, and then transfer the uniformly dispersed mixed solution to a microwave reactor for microwave heating reaction. Microwave reaction is carried out for 1 hour at a microwave power of 300W and a temperature of 80℃; after the reaction, centrifuge at 8000rpm for 10 minutes to separate the solid product. Wash the solid product with ethanol 3 times, using 30mL of ethanol each time, to ensure the removal of unreacted organic solvents and impurities. Place the washed solid product in a vacuum drying oven; vacuum dry at 60℃ for 12 hours to obtain the dried ternary composite system of silver-loaded titanium dioxide, zinc oxide / chitosan complex and quaternary ammonium salt modified montmorillonite.

[0041] The preparation steps of modified graphite sheets are as follows:

[0042] (1) Dissolve 50 mL of tetrabutoxytitanium (TBOT) in 100 mL of ethanol, and then slowly add 10 mL of 1% dilute nitric acid solution to the mixture under vigorous stirring. After the addition is complete, continue stirring for 12 h to prepare a stable titanium dioxide sol.

[0043] (2) Dissolve 50 mL of tetraethoxysilane (TEOS) in 100 mL of ethanol, then heat to 50 °C and slowly add 10 mL of 1% ammonia solution to the mixture under vigorous stirring. After the addition is complete, continue stirring for 8 h to prepare a stable silica sol.

[0044] (3) Place 5g of graphite sheet substrate in 100mL of acetone and 100mL of ethanol and ultrasonically clean for 30min to remove surface impurities. Then dry the cleaned graphite sheet substrate in an oven at 100℃ for 6h to obtain a clean graphite sheet substrate;

[0045] (4) The clean graphite sheet substrate obtained in step (3) is immersed in the titanium dioxide sol obtained in step (1) for 5 minutes and then removed; after standing for 15 minutes, it is dried at 80°C for 30 minutes, and then heated to 400°C and held for 1 hour under a nitrogen atmosphere to complete the curing process and obtain a graphite sheet substrate coated with one layer of titanium dioxide; the obtained graphite sheet substrate coated with one layer of titanium dioxide is immersed in the silica sol obtained in step (2) and subjected to the same immersion, lifting, drying and curing. The above deposition steps are repeated alternately until the total number of film layers reaches 10 layers. Finally, the graphite sheet substrate coated with silica and titanium dioxide protective layers is dried at 110°C for 6 hours, heated to 500°C and held for 2 hours under a nitrogen atmosphere, and then cooled to room temperature to obtain a graphite sheet substrate modified with silica and titanium dioxide, denoted as TiO2-SiO2-G;

[0046] (5) Dissolve 2g of silane coupling agent KH−550 in 100mL of 90:10 ethanol-water mixed solvent, and then add 1% dilute nitric acid solution to adjust the pH of the system to 4; stir the solution for 30min to hydrolyze and activate the silane group to obtain the activated coupling agent solution.

[0047] (6) The silica and titanium dioxide modified graphite sheet substrate obtained in step (4) is immersed in the activated coupling agent solution obtained in step (5), and stirred at 70°C for 4 hours. The graphite sheet substrate is then removed and washed three times with 30 mL of ethanol to remove unreacted coupling agent. Finally, it is heated and dried in an oven at 110°C for 2 hours to promote the condensation and curing of the grafted silane coupling agent, and the modified graphite sheet KH−550-TiO2-SiO2-G is finally obtained.

[0048] Example 1:

[0049] The preparation steps of gravure pearlescent ink are as follows:

[0050] (1) Pre-dispersion stage: 10g of modified graphite flakes KH−550-TiO2-SiO2-G and 15g of n-propyl acetate (accounting for part of the solvent system) were added to the dispersion vessel for high-speed shear dispersion: first, the high-speed shear dispersion was carried out at 6000rpm for 20min at 55℃, then the temperature was lowered to 35℃ and 1.0g of hexadecyltrimethylammonium chloride was added, and the high-speed shear dispersion was continued at 7000rpm for 30min; finally, the dispersion was filtered through a 325-mesh sieve (the filter residue rate was ≤0.1%) to prepare the pearlescent pigment dispersion.

[0051] (2) Resin dissolution stage: 10g of acrylic modified polyurethane, 5g of nitrocellulose, 10g of isophorone, 5g of γ-butyrolactone and 10g of n-propyl acetate were added to the pearl pigment dispersion prepared in step (1); the resulting mixture was heated to 60°C and stirred until the viscosity stabilized (approximately 1 hour) to obtain the pearl ink mixture.

[0052] (3) The pearlescent ink mixture obtained in step (2) is placed in a three-roll mill for three passes of grinding. The specific process parameters are as follows:

[0053] First pass: Roller spacing 40μm, roller temperature 30℃;

[0054] Second pass: Roller spacing 20μm, roller temperature 40℃;

[0055] Third pass: Roller spacing 10μm, roller temperature 50℃;

[0056] Pearlescent ink abrasive was prepared;

[0057] (4) Add 1g of organosilicon leveling agent (BYK-333), 0.5g of polyether modified silicone oil defoamer (TEGO Airex 900), 1.5g of benzotriazole UV absorber (Tinuvin 384-2), 0.2g of hindered amine light stabilizer (Tinuvin 123), 2.5g of nano alumina dispersion (20wt% solid content), 0.8g of silver-loaded titanium dioxide, zinc oxide / chitosan complex and quaternary ammonium salt modified montmorillonite ternary composite antibacterial agent, 3g of fumed silica (Aerosil200) and 5g of n-propyl acetate to the abrasive obtained in step (3). Disperse the resulting mixture by ultrasonic treatment: treatment time 60min, ultrasonic frequency 30kHz, to ensure that all components are uniformly dispersed, and the final gravure pearlescent ink can be obtained.

[0058] The prepared gravure pearlescent ink was coated and then its performance was tested. The coating was prepared according to the method provided in GB / T1727-1992, with the following specific steps: Tinplate conforming to GB / T 2520-2017 was cut into test plates with dimensions of 50mm × 120mm × 0.3mm, and the test plates were cleaned according to the requirements for test plates in GB 9271-1988. The material was evenly coated onto the tinplate test plate using a scraper, and after drying, its various properties were tested. The hardness and adhesion of the coating were measured according to the corresponding national standards, specifically: hardness according to GB / T 1730-93, adhesion according to GB / T 1720-79, gloss according to GB / T 9754-2007, lightfastness according to GB / T 1865-2009, and leveling property according to GB / T 1750-1979. The antibacterial properties of the coating can be tested using the film application method according to standard QB / T 2591-2003 (QB / T 2591-2003, Test Methods and Antibacterial Effects of Antibacterial Plastics [S]. Beijing: National Development and Reform Commission of the People's Republic of China, 2003.), examining the antibacterial rate after 24 hours of contact between the antibacterial coating and test bacteria. The total bacterial count was determined according to GB / T 4789.2-2016 (GB / T 4789.2-2016, Determination of Total Bacterial Count in Food Microbiology [S]. Beijing: National Health and Family Planning Commission of the People's Republic of China, State Food and Drug Administration, 2016.), and the antibacterial rate was calculated using the following formula:

[0059] R% = (BA) / B × 100%

[0060] In the formula: R: antibacterial rate, %; A: the average number of recovered colonies after 24 hours of incubation of the 5%NH2-ZnO / SiO2-0.1%β-CD-CDs-PU-2 coating sample; B: the average number of recovered colonies after 24 hours of incubation of the blank control sample, which is a coating made by the same method from pure PU and curing agent polyamide resin (mass ratio of 1:1).

[0061] The results show that the coating prepared by this invention has the following significant effects compared with the coating prepared by the same method using pure PU and curing agent polyamide resin (mass ratio of 1:1):

[0062] Adhesion level improved from level 3 to level 0;

[0063] Impact strength (50 kg·cm) was improved from cracked to crack-free;

[0064] The hardness was increased from 1H to 6H;

[0065] Gloss: 88 GU at a 60° angle;

[0066] Lightfastness: QUV test (1000 hours), ΔE < 1.0;

[0067] Leveling properties: The coating surface is smooth, and the leveling time is ≤9 seconds;

[0068] The antibacterial rates against Escherichia coli and Staphylococcus aureus increased from 0% and 0% to 98.5% and 99.1%, respectively.

[0069] Therefore, the coating prepared according to the preparation method of this embodiment not only has high mechanical properties but also excellent antibacterial properties.

[0070] Example 2:

[0071] The preparation of gravure pearlescent ink is the same as in Example 1, except that the modified graphite flakes KH−550-TiO2-SiO2-G in step (1) are replaced with TiO2-SiO2-G, and the rest of the steps are the same as in Example 1.

[0072] The preparation and performance characterization of the coating were carried out in accordance with Example 1; the results showed that the coating prepared in this example has the following significant effects:

[0073] Adhesion level improved from level 3 to level 1;

[0074] The hardness was increased from 1H to 5H;

[0075] Gloss: 87 GU at a 60° angle;

[0076] Lightfastness: QUV test (1000 hours), ΔE < 1.0;

[0077] Leveling properties: The coating surface is smooth, and the leveling time is ≤9 seconds;

[0078] The antibacterial rates against Escherichia coli and Staphylococcus aureus increased from 0% and 0% to 98.4% and 99.0%, respectively.

[0079] Example 3:

[0080] The preparation of gravure pearlescent ink is the same as in Example 1, except that the acrylic modified polyurethane in step (2) is replaced with polyurethane, and the rest of the steps are the same as in Example 1.

[0081] The preparation and performance characterization of the coating were carried out in accordance with Example 1; the results showed that the coating prepared in this example has the following significant effects:

[0082] Adhesion level improved from level 3 to level 1;

[0083] The hardness was increased from 1H to 4H;

[0084] Gloss: 85 GU at a 60° angle;

[0085] Lightfastness: QUV test (1000 hours), ΔE < 1.0;

[0086] Leveling property: The coating surface is smooth, and the leveling time is ≤10 seconds;

[0087] The antibacterial rates against Escherichia coli and Staphylococcus aureus increased from 0% and 0% to 98.1% and 98.9%, respectively.

[0088] Example 4:

[0089] The preparation of gravure pearlescent ink is based on Example 1, except that the antibacterial agent in step (3) of the silver-loaded titanium dioxide, zinc oxide / chitosan complex and quaternary ammonium salt modified montmorillonite ternary composite system is replaced with silver-loaded titanium dioxide.

[0090] The preparation and performance characterization of the coating were carried out in accordance with Example 1; the results showed that the coating prepared in this example has the following significant effects:

[0091] Adhesion level improved from level 3 to level 0;

[0092] Impact strength (50 kg·cm) was improved from cracked to crack-free;

[0093] The hardness was increased from 1H to 6H;

[0094] Gloss: 88 GU at a 60° angle;

[0095] Lightfastness: QUV test (1000 hours), ΔE < 1.0;

[0096] Leveling properties: The coating surface is smooth, and the leveling time is ≤9 seconds;

[0097] The antibacterial rates against Escherichia coli and Staphylococcus aureus increased from 0% and 0% to 88.9% and 89.2%, respectively.

[0098] Example 5:

[0099] The preparation of gravure pearlescent ink is based on Example 1, except that the antibacterial agent in step (3) of the silver-loaded titanium dioxide, zinc oxide / chitosan complex and quaternary ammonium salt modified montmorillonite ternary composite system is replaced with zinc oxide / chitosan complex.

[0100] The preparation and performance characterization of the coating were carried out in accordance with Example 1; the results showed that the coating prepared in this example has the following significant effects:

[0101] Adhesion level improved from level 3 to level 0;

[0102] Impact strength (50 kg·cm) was improved from cracked to crack-free;

[0103] The hardness was increased from 1H to 6H;

[0104] Gloss: 88 GU at a 60° angle;

[0105] Lightfastness: QUV test (1000 hours), ΔE < 1.0;

[0106] Leveling properties: The coating surface is smooth, and the leveling time is ≤9 seconds;

[0107] The antibacterial rates against Escherichia coli and Staphylococcus aureus increased from 0% and 0% to 77.5% and 83.1%, respectively.

[0108] Example 6:

[0109] The preparation of gravure pearlescent ink is based on Example 1, except that the antibacterial agent in the ternary composite system of silver-loaded titanium dioxide, zinc oxide / chitosan complex and quaternary ammonium salt modified montmorillonite in step (3) is replaced with quaternary ammonium salt modified montmorillonite.

[0110] The preparation and performance characterization of the coating were carried out in accordance with Example 1; the results showed that the coating prepared in this example has the following significant effects:

[0111] Adhesion level improved from level 3 to level 0;

[0112] Impact strength (50 kg·cm) was improved from cracked to crack-free;

[0113] The hardness was increased from 1H to 6H;

[0114] Gloss: 88 GU at a 60° angle;

[0115] Lightfastness: QUV test (1000 hours), ΔE < 1.0;

[0116] Leveling properties: The coating surface is smooth, and the leveling time is ≤9 seconds;

[0117] The antibacterial rates against Escherichia coli and Staphylococcus aureus increased from 0% and 0% to 69.4% and 72.8%, respectively.

[0118] Comparative Example 1:

[0119] The preparation of gravure pearlescent ink is based on Example 1, except that the modified graphite sheet KH−550-TiO2-SiO2-G in step (1) is replaced with mica sheet, and the other steps are the same as in Example 1.

[0120] The preparation and performance characterization of the coating were carried out in accordance with Example 1; the results showed that the coating prepared in this example has the following significant effects:

[0121] Adhesion level improved from level 3 to level 1;

[0122] The hardness was increased from 1H to 5H;

[0123] Gloss: 71 GU at a 60° angle;

[0124] Lightfastness: QUV test (1000 hours), ΔE < 1.0;

[0125] Leveling properties: The coating surface is smooth, and the leveling time is ≤10 seconds; the antibacterial rates against Escherichia coli and Staphylococcus aureus have increased from 0% and 0% to 98.3% and 99.0%, respectively.

Claims

1. A gravure pearlescent ink characterised in that, The intaglio pearlescent ink is composed of a base resin system, an environmentally friendly solvent system, a pearlescent pigment and an additive; wherein the base resin system is a mixture of acrylic modified polyurethane and nitrocellulose; the environmentally friendly solvent system is a mixture of n-propyl acetate, isophorone and gamma-butyrolactone; the additive is composed of a leveling agent, a defoaming agent and a light stabilizer; the pearlescent pigment is a TiO2 / SiO2 modified graphite flake, and the TiO2 / SiO2 modified graphite flake comprises a TiO2 / SiO2 alternating multilayer film structure. The TiO2 / SiO2 alternating multilayer film structure comprises: 5-15 layers of alternately deposited metal oxide layers, with a single layer thickness of 10-50 nm; the outermost layer is a SiO2 protective layer, with a thickness accounting for 10-20% of the total thickness of the film layer; the surface of the film layer is grafted with 0.5-5 wt% of a silane coupling agent, and the coupling agent is selected from at least one of KH-550 and KH-570.

2. The intaglio pearlescent ink according to claim 1, wherein The acrylic modified polyurethane and the nitrocellulose in the base resin system are in a mass ratio of 3:1-1:

3.

3. The intaglio pearlescent ink according to claim 1, wherein The additive comprises: 0.1-2 wt% of a silicone leveling agent, 0.05-1 wt% of a polyether modified silicone oil defoaming agent, 0.1-3 wt% of a benzotriazole ultraviolet absorber, and 0.05-0.5 wt% of a hindered amine light stabilizer.

4. The intaglio pearlescent ink according to claim 1, wherein It also comprises: 0.5-5 wt% of a nano-alumina dispersion liquid, 0.5-1 wt% of an antibacterial agent dispersion liquid, and 1-10 wt% of a thixotropic agent; wherein the thixotropic agent is selected from at least one of organic bentonite or fumed silica.

5. A method of preparing the intaglio pearlescent ink according to any one of claims 1 to 4, characterized in that, Specifically comprising the following steps: (1) Pre-dispersion stage: high-speed shearing dispersion of the pearlescent pigment with part of the solvent at a shearing rate of 5000-15000 rpm to obtain a pearlescent pigment dispersion liquid; (2) Resin dissolution stage: adding the base resin system and the remaining solvent to the pearlescent pigment dispersion liquid prepared in step (1), and then heating and stirring the obtained mixture to disperse until the viscosity is stable to obtain a pearlescent ink mixture; (3) Fine grinding stage: placing the pearlescent ink mixture prepared in step (2) into a three-roll mill for 3-5 passes of grinding, controlling the roll gap to be 5-50 μm to prepare a pearlescent ink grinding material; (4) Post-adjustment stage: adding the additive to the pearlescent ink grinding material prepared in step (3) and uniformly dispersing to obtain the pearlescent ink.

6. The method of claim 5, wherein the intaglio pearlescent ink is prepared by the steps of: The pre-dispersion stage comprises the following stages: First stage: dispersion at 5000-8000 rpm for 10-30 min at 50-60℃; Second stage: after cooling to 30-40℃, adding a surface treatment agent and dispersing at 7000 rpm for 15-45 min; Third stage: filtering through a 325 mesh screen, with a filter residue rate ≤0.1%.

7. The method of claim 5, wherein the intaglio pearlescent ink is prepared by the steps of: The heating and stirring temperature of the resin dissolution stage is 50-80℃.

8. The method of claim 5, wherein the intaglio pearlescent ink is prepared by the steps of: The process parameters of the fine grinding stage are: First pass: roll gap 30-50 μm, roll temperature 25-35℃; Second pass: roll gap 15-30 μm, roll temperature 35-45℃; Third pass: roll gap 5-15 μm, roll temperature 45-55℃.

9. The method for preparing gravure pearlescent ink according to claim 5, characterized in that, The dispersion treatment mode in the post-adjustment stage is ultrasonic treatment; the treatment time is 30-120 min, and the ultrasonic frequency is 20-40 kHz. The dispersion treatment mode in the post-adjustment stage is ultrasonic treatment; the treatment time is 30-120 min, and the ultrasonic frequency is