Bacteriostatic aromatic water-based ink and preparation method thereof

Abstract

The invention discloses bacteriostatic aromatic water-based ink and a preparation method, and the bacteriostatic aromatic water-based ink comprises 30-50 parts of water-based acrylic resin, 0.5-2 parts of a nano-silver antibacterial agent, 1-5 parts of natural plant perfume, 1-3 parts of a dispersing agent, 0.5-1.5 parts of a defoaming agent, 1-3 parts of a thickening agent, 30-50 parts of deionized water and 5-20 parts of water-based pigment. The water-based acrylic resin is an acrylate polymer containing carboxyl, hydroxyl and other polar groups, the solid content of the water-based acrylic resin is 40%-50%, microorganisms are effectively prevented from breeding on the surface of a package by adding the nano-silver antibacterial agent, and the natural plant essential oil is added into the ink as perfume, so that the ink has aromatic odor, and the ink can be applied to the packaging industry. A polyacrylate compound is used as a dispersing agent, can effectively reduce surface tension among solid particles such as water-based pigment and a nano-silver antibacterial agent and prevent particle aggregation, and is matched with hydroxyethyl cellulose as a thickening agent, so that the viscosity of the printing ink can be accurately adjusted, the printing ink is uniformly transferred in the printing process, and the phenomena of sagging, layering, precipitation and the like are not easy to occur; and the stability of printing ink quality is ensured.

Description

Technical Field

[0001] The invention belongs to the technical field of inks, and in particular relates to an antibacterial aromatic water-based ink and a preparation method thereof. Background Art

[0002] In the printing industry, ink performance is crucial to the quality of printed products. Traditional organic solvent-based inks are currently the most commonly used choice for printing. However, as people pay more attention to health and quality of life, packaging printing in areas such as food, medicine, and cosmetics places higher demands on the safety and functionality of inks.

[0003] Most of the existing inks, whether water-based or solvent-based, are difficult to meet the dual needs of antibacterial and aromatic properties. Although some water-based inks have reduced VOCs emissions, they are insufficient in terms of functional expansion, pigment dispersion stability, and printability. On the one hand, they do not take into account the realization of antibacterial and aromatic functions, and cannot meet the needs of packaging printing such as food, medicine, and cosmetics, as well as the high-end printing market; on the other hand, they are insufficient in terms of ink stability, and are prone to stratification and precipitation after long-term storage, which leads to problems such as pigment agglomeration, plate blocking, and poor clarity of printed patterns during the printing process, affecting printing efficiency and product quality. Summary of the invention

[0004] The object of the present invention is to provide an antibacterial aromatic water-based ink and a preparation method thereof, so as to solve the problems raised in the above-mentioned background technology.

[0005] To achieve the above object, the present invention provides the following technical solution: an antibacterial aromatic water-based ink, comprising, by weight:

[0006] 30-50 parts of water-based acrylic resin, 0.5-2 parts of nano-silver antibacterial agent, 1-5 parts of natural plant fragrance, 1-3 parts of dispersant, 0.5-1.5 parts of defoaming agent, 1-3 parts of thickener, 30-50 parts of deionized water, and 5-20 parts of water-based pigment.

[0007] Preferably, the aqueous acrylic resin comprises 35 parts, nano-silver antibacterial agent 1 part, natural plant fragrance 3 parts, dispersant 2 parts, defoamer 1 part, thickener 1 part, deionized water 50 parts, and aqueous pigment 10 parts.

[0008] Preferably, the water-based acrylic resin is an acrylic ester polymer containing polar groups such as carboxyl and hydroxyl groups, and has a solid content of 40%-50%.

[0009] Preferably, the nano silver antibacterial agent is nano silver particles with a particle size in the range of 20-70 nm, and its surface is treated with special organic coating. The natural plant fragrance is essential oil extracted from plants such as lavender, mint, and rose. The dispersant is a polyacrylate compound, and the thickener is hydroxyethyl cellulose capable of adjusting the viscosity of the ink.

[0010] A preparation method of an antibacterial aromatic water-based ink specifically includes the following steps:

[0011] S1. Add the water-based acrylic resin into a reaction kettle equipped with a stirring device and a temperature control system and stir. During the stirring process, slowly add the dispersant and deionized water to fully dissolve and disperse the water-based acrylic resin in the deionized water to form a uniform resin dispersion.

[0012] S2. Add the water-based pigment into the formed resin dispersion to fully disperse the pigment in the resin dispersion to form a uniform pigment dispersion.

[0013] S3. Add the nano silver antibacterial agent and the natural plant fragrance into the pigment dispersion to evenly disperse the nano silver antibacterial agent and the natural plant fragrance in the pigment dispersion.

[0014] S4. Add an antifoaming agent to eliminate the bubbles generated during the stirring process, then slowly add the thickener, and monitor the viscosity change of the ink in real time. According to the requirements of different printing processes, adjust the ink viscosity to a suitable range to finally obtain the antibacterial aromatic water-based ink.

[0015] Preferably, in step S1, after starting the stirring device, set the stirring speed to 300-500 r / min, and at the same time control the temperature in the reaction kettle at 30-50 °C. After adding the dispersant and deionized water, continue stirring for 30-60 min to form a uniform resin dispersion.

[0016] Preferably, in step S2, after adding the water-based pigment, increase the stirring speed of the reaction kettle to 800-1200 r / min and stir for 40-60 min.

[0017] Preferably, in step S3, when adding the natural plant fragrance, keep the reaction kettle in a sealed state to reduce the volatilization of the fragrance, and maintain the stirring speed at 800-1200 r / min and stir for 30-50 min.

[0018] Preferably, in step S4, after adding the antifoaming agent, continue stirring at a stirring speed of 300-500 r / min for 15-30 min, and after slowly adding the thickener, continue stirring at a speed of 300-500 r / min for 30-60 min.

[0019] Preferably, in the step S1, the dispersant and deionized water can be added dropwise at a dropping rate of 1-5 mL / min. Slowly dropping can make the waterborne acrylic resin mix more fully with the dispersant and deionized water, improving the dispersion effect.

[0020] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0021] (1) By adding nano silver antibacterial agent, and its surface is treated with special organic coating, it can be more stably dispersed in the ink. The nano silver antibacterial agent can effectively prevent the growth of microorganisms on the packaging surface by virtue of its nano-scale tiny size and high specific surface area, greatly extending the shelf life of food; and by adding natural plant essential oils as spices to the ink, the ink is given a natural and pleasant aromatic smell, so that after the ink dries into a film, these spices can continuously and slowly release fragrance, enhancing the consumer's use experience.

[0022] (2) By using polyacrylate compounds as dispersants, the surface tension between solid particles such as waterborne pigments and nano silver antibacterial agents can be effectively reduced, preventing particle agglomeration and enabling them to be evenly dispersed in the aqueous medium, ensuring that the ink has good dispersion stability. And by adding a suitable defoaming agent, the bubbles generated during the stirring process can be effectively eliminated, avoiding the influence of bubbles on the printing quality and ensuring the clarity and integrity of the printed pattern. In combination with hydroxyethyl cellulose as a thickener, the viscosity of the ink can be precisely adjusted to meet the requirements of various printing processes such as offset printing, gravure printing, and flexographic printing. During the printing process, the ink is transferred evenly and is not prone to phenomena such as sagging, delamination, and precipitation, ensuring the stability of the ink quality. Specific embodiments

[0023] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0024] The present invention provides a preparation method of an antibacterial and aromatic waterborne ink:

[0025] Example 1

[0026] Raw material preparation: Accurately weigh 35 parts of waterborne acrylic resin, 1 part of nano silver antibacterial agent, 3 parts of natural plant fragrance, 2 parts of dispersant, 1 part of defoamer, 1 part of thickener, 50 parts of deionized water, and 10 parts of yellow waterborne pigment. Among them, the waterborne acrylic resin is a product with a solid content of 40%, the particle size of the nano silver antibacterial agent is 20 - 70 nm, the lavender essential oil is a pure natural essential oil extracted by steam distillation method, the dispersant is sodium polyacrylate salt, the defoamer is a silicone defoamer, and the thickener is hydroxyethyl cellulose.

[0027] Preparation process

[0028] Pre - dispersion step: Slowly add the waterborne acrylic resin into a 500 mL reaction kettle equipped with a stirring paddle and a thermometer. Turn on the stirring device, adjust the stirring speed to 300 r / min, and then, under stirring, slowly add the dispersant and deionized water, and continuously stir for 30 min. During the stirring process, observe the dissolution of the resin and the uniformity of the system to ensure that the waterborne acrylic resin is fully dissolved in the deionized water to form a uniform light yellow resin dispersion.

[0029] Addition of antibacterial agent and fragrance step: After the resin dispersion is uniform, add the nano silver antibacterial agent and lavender essential oil into the reaction kettle in sequence, quickly increase the stirring speed to 800 r / min, and stir for 40 min. During the stirring process, it can be observed that the system gradually becomes uniform and the fragrance of the lavender essential oil begins to emit. Since the densities of the nano silver antibacterial agent and lavender essential oil are different from those of the resin dispersion, high - speed stirring can make them fully dispersed, avoiding agglomeration and stratification phenomena.

[0030] Defoaming and thickening step: After stirring for 40 min, add the defoamer and continue to stir for 15 min. At this time, it can be observed that the bubbles in the system gradually decrease and disappear. Then, slowly add the thickener and stir for 30 min. During the stirring of the thickener, use a viscometer to measure the viscosity of the ink every 5 min. When the ink viscosity reaches the target value (such as the viscosity of the coating - 4 cup is 40 - 60 s), stop stirring to obtain the antibacterial aromatic waterborne ink. Fill the prepared ink into a sealed container for standby.

[0031] Example two

[0032] Raw material preparation: Weigh 40 parts of waterborne acrylic resin, 1 part of nano silver antibacterial agent, 3 parts of peppermint essential oil, 2 parts of dispersant, 1 part of defoamer, 2 parts of thickener, 40 parts of deionized water, and 15 parts of red waterborne pigment. Among them, the solid content of the waterborne acrylic resin is 45%, the particle size of the nano silver antibacterial agent is 30 - 60 nm, the peppermint essential oil is a high - purity essential oil extracted by supercritical carbon dioxide extraction method, the dispersant is a polycarboxylate dispersant, the defoamer is a polyether - modified silicone defoamer, and the thickener is a polyurethane thickener.

[0033] Preparation process

[0034] Pre-dispersion step: Add the waterborne acrylic resin into a 1000 mL reaction kettle, turn on the stirring device, set the stirring speed to 400 r / min, slowly add the dispersant and deionized water, and stir for 45 min to fully dissolve and disperse the waterborne acrylic resin to form a uniform resin dispersion. During the stirring process, pay attention to observing the temperature change of the system to avoid the temperature being too high due to too fast stirring speed, which may affect the performance of the resin;

[0035] Step of adding antibacterial agent and fragrance: Add nano-silver antibacterial agent and peppermint essential oil to the resin dispersion, increase the stirring speed to 1000 r / min, and stir for 50 min. During the stirring process, the cool fragrance of peppermint essential oil gradually fills the entire reaction kettle. To ensure the uniform dispersion of nano-silver antibacterial agent and peppermint essential oil, the stirring time can be appropriately extended, while avoiding excessive stirring resulting in excessive volatilization of the fragrance;

[0036] Defoaming and thickening steps: Add the defoaming agent and stir for 20 min, observe the disappearance of bubbles. After the bubbles are basically eliminated, add the thickening agent and stir for 45 min. During the stirring process of the thickening agent, closely monitor the change of the ink viscosity. By adjusting the addition amount of the thickening agent, control the ink viscosity within the ideal range (such as the viscosity of the coating - 4 cup is 50 - 70 s). Seal the prepared ink for subsequent testing and use.

[0037] Example 3

[0038] Raw material preparation: Weigh 50 parts of waterborne acrylic resin, 2 parts of nano-silver antibacterial agent, 5 parts of rose essential oil, 3 parts of dispersant, 1.5 parts of defoaming agent, 3 parts of thickening agent, 30 parts of deionized water, and 15 parts of blue waterborne pigment. The solid content of the waterborne acrylic resin is 50%, the particle size of the nano-silver antibacterial agent is 40 - 70 nm, the rose essential oil is extracted by solvent extraction method and refined, the dispersant is a polymer type dispersant, the defoaming agent is a mineral oil type defoaming agent, and the thickening agent is a hydrophobic modified alkali-swellable thickening agent;

[0039] Preparation process

[0040] Pre-dispersion step: Pour the waterborne acrylic resin into a 2000 mL reaction kettle, turn on the stirring device, adjust the stirring speed to 500 r / min, and sequentially add the dispersant and deionized water, and stir for 60 min to completely dissolve the waterborne acrylic resin and form a uniform dispersion system. During the stirring process, the reaction kettle can be appropriately heated (the temperature is controlled at 40 - 50 °C) to accelerate the dissolution rate of the resin, while avoiding the resin decomposition caused by too high temperature;

[0041] Steps for adding antibacterial agent and fragrance: Add nano-silver antibacterial agent and rose essential oil, increase the stirring speed to 1200 r / min, and stir for 60 min. The fragrance of rose essential oil is strong. During the stirring process, pay attention to the sealing of the reaction kettle to reduce the volatilization loss of the essential oil. At the same time, high-speed stirring can make the nano-silver antibacterial agent and rose essential oil fully dispersed in the resin dispersion, ensuring the uniform performance of the ink.

[0042] Steps for defoaming and thickening: Add defoaming agent and stir for 30 min to ensure complete elimination of bubbles. Then add thickening agent and stir for 60 min. When stirring the thickening agent, adopt the method of slow addition and stir while adding to make the thickening agent fully react with the ink system, and adjust the ink viscosity to the appropriate range (such as the viscosity of No. 4 cup is 60 - 80 s). After preparation, filter the ink to remove possible impurities, and then store it in a sealed barrel.

[0043] Comparative Example 1: Do not add nano-silver antibacterial agent and natural plant fragrance, and the other raw materials and preparation steps are the same as those in Examples 1 - 3.

[0044] Table 1 Comparative experimental results of the ink of the present invention and traditional ink in Comparative Example 1

[0045]

[0046]

[0047] Testing method of Table 1

[0048] Antibacterial performance test: Adopt the plate colony counting method. Culture Escherichia coli and Staphylococcus aureus to the logarithmic growth phase respectively, dilute them to a certain concentration with physiological saline, take 0.1 mL of the diluted bacterial solution and spread it evenly on the nutrient agar medium plate. Then soak sterile filter paper with a diameter of 6 mm in different ink samples of Comparative Example 1 and Examples 1 - 3 respectively. After taking out, drain the excess ink, place it on the plate coated with the bacterial solution, and place the plate in a constant temperature incubator at 37 °C for 24 h. Then observe and measure the diameter of the antibacterial circle.

[0049] There is no antibacterial circle in Comparative Example 1;

[0050] The diameter of the antibacterial circle of Escherichia coli in Example 1 is 15 mm, and the diameter of the antibacterial circle of Staphylococcus aureus is 13 mm;

[0051] The diameter of the antibacterial circle of Escherichia coli in Example 2 is 18 mm, and the diameter of the antibacterial circle of Staphylococcus aureus is 18 mm;

[0052] The diameter of the antibacterial circle of Escherichia coli in Example 3 is 20 mm, and the diameter of the antibacterial circle of Staphylococcus aureus is 18 mm.

[0053] Aromatic odor test: 30 professional olfactory evaluators were invited to evaluate the aromatic odor of the ink prints. The ink was printed on the same paper, and after the ink dried, the evaluators were asked to score the intensity of the aromatic odor, the purity of the fragrance, and the persistence of the fragrance retention of the prints (1 - 10 points);

[0054] Comparative Example 1 had no aromatic odor;

[0055] In Example 1, the odor intensity was 7 points and the fragrance purity was 8 points;

[0056] In Example 2, the odor intensity was 8 points and the fragrance purity was 8 points;

[0057] In Example 3, the odor intensity was 9 points and the fragrance purity was 8 points.

[0058] Dispersion stability test: The ink samples were placed in a centrifuge and centrifuged at a speed of 3000 r / min for 30 min, and then the layering situation of the ink was observed. If layering occurred, the ratio of the layering height to the total height of the ink was recorded; if no layering occurred, it was recorded as no layering;

[0059] In Comparative Example 1, obvious layering occurred;

[0060] In Example 1, there was no layering;

[0061] In Example 2, there was no layering;

[0062] In Example 3, there was no layering.

[0063] Printing suitability test: Printing tests were carried out on an offset press, a gravure press, and a flexographic press, and the ink transfer performance, dot reproduction, and print clarity during the printing process were observed. Good ink transfer performance means that the ink can be smoothly transferred from the printing plate to the substrate without ink leakage or ghosting; high dot reproduction means that the dots on the print are highly similar to the original dots; high print clarity means that the pattern edges are clear and the text strokes are sharp.

[0064] In Comparative Example 1, ink spraying occurred during printing on the offset press, the dot reproduction was poor (the dot gain rate exceeded 20%), and the print clarity was low; it was easy to clog the plate on the gravure press; the ink transfer was uneven on the flexographic press;

[0065] In Example 1, during printing on the offset press, the gravure press, and the flexographic press, the ink transfer performance was good, the dot reproduction was high (the dot gain rate was between 10% and 15%), and the print clarity was high;

[0066] In Example 2, during printing on the offset press, the gravure press, and the flexographic press, the ink transfer performance was good, the dot reproduction was high (the dot gain rate was between 8% and 12%), and the print clarity was high;

[0067] Example 3 When printing on offset printers, gravure printers, and flexographic printers, the ink transfer performance is good, the dot reproduction is high (the dot gain rate is between 5% and 10%), and the print clarity is high.

[0068] Viscosity stability test: After placing the ink sample at room temperature for 7 days, use a viscometer to measure the viscosity of the ink and compare it with the initial viscosity, and calculate the viscosity change rate. Viscosity change rate = (viscosity after 7 days - initial viscosity) / initial viscosity × 100%.

[0069] Comparative Example 1 The viscosity change rate is 15%;

[0070] Example 1 The viscosity change rate is 5%;

[0071] Example 2 The viscosity change rate is 4%;

[0072] Example 3 The viscosity change rate is 3%.

[0073] From the above examples, it can be clearly seen the specific preparation process and effects of the antibacterial aromatic water-based ink of the present invention under different raw material ratios. In practical applications, according to different printing requirements and product positioning, the types and amounts of raw materials can be flexibly adjusted to prepare ink products that meet specific requirements.

[0074] Finally, it should be noted that the above are only the preferred embodiments of the present invention and are not used to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, for those skilled in the art, they can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements for some of the technical features. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. An antibacterial aromatic water-based ink, characterized in that, By weight parts, it includes: 30 - 50 parts of waterborne acrylic resin, 0.5 - 2 parts of nano silver antibacterial agent, 1 - 5 parts of natural plant fragrance, 1 - 3 parts of dispersant, 0.5 - 1.5 parts of defoamer, 1 - 3 parts of thickener, 5 - 20 parts of waterborne pigment, and the balance is deionized water.

2. The antibacterial aromatic water-based ink according to claim 1, characterized in that, By weight parts, it includes: 35 parts of the waterborne acrylic resin, 1 part of nano silver antibacterial agent, 3 parts of natural plant fragrance, 2 parts of dispersant, 1 part of defoamer, 1 part of thickener, 50 parts of deionized water, and 10 parts of waterborne pigment.

3. The antibacterial aromatic water-based ink according to claim 1, wherein: The waterborne acrylic resin is an acrylate polymer containing polar groups such as carboxyl and hydroxyl groups, and its solid content is 40% - 50%.

4. The antibacterial aromatic water-based ink according to claim 1, wherein: The nano silver antibacterial agent is nano - scale silver particles with a particle size in the range of 20 - 70nm, and its surface is treated with organic coating. The natural plant fragrance is essential oil extracted from lavender, mint, and rose plants. The dispersant is a polyacrylate compound, and the thickener is hydroxyethyl cellulose capable of adjusting the viscosity of the ink.

5. A method for preparing an antibacterial aromatic aqueous ink according to any one of claims 1-4, characterized in that, Specifically, it includes the following steps: S1. Add the waterborne acrylic resin into a reaction kettle equipped with a stirring device and a temperature control system and stir. During the stirring process, slowly add the dispersant and deionized water to make the waterborne acrylic resin fully dissolve and disperse in the deionized water to form a uniform resin dispersion. S2. Add the waterborne pigment to the formed resin dispersion to make the pigment fully disperse in the resin dispersion to form a uniform pigment dispersion. S3. Add the nano silver antibacterial agent and natural plant fragrance to the pigment dispersion to make the nano silver antibacterial agent and natural plant fragrance evenly disperse in the pigment dispersion. S4. Add the defoamer to eliminate the bubbles generated during the stirring process, then slowly add the thickener, and monitor the viscosity change of the ink in real - time. According to the requirements of different printing processes, adjust the ink viscosity to the appropriate range to finally obtain the antibacterial and aromatic waterborne ink.

6. The preparation method of an antibacterial aromatic water-based ink according to claim 5, wherein: In step S1, after starting the stirring device, set the stirring speed to 300 - 500r / min, and at the same time control the temperature in the reaction kettle at 30 - 50°C. After adding the dispersant and deionized water, continue to stir for 30 - 60min to form a uniform resin dispersion.

7. The preparation method of an antibacterial aromatic water-based ink according to claim 5, wherein: In step S2, after adding the waterborne pigment, increase the stirring speed of the reaction kettle to 800 - 1200r / min and stir for 40 - 60min.

8. The preparation method of an antibacterial aromatic water-based ink according to claim 5, wherein: In step S3, when adding the natural plant fragrance, keep the reaction kettle in a sealed state to reduce the volatilization of the fragrance, and maintain the stirring speed at 800 - 1200r / min and stir for 30 - 50min.

9. The preparation method of an antibacterial aromatic water-based ink according to claim 5, characterized in that: In step S4, after adding the defoamer, continue to stir at a stirring speed of 300 - 500r / min for 15 - 30min, and after slowly adding the thickener, continue to stir at a speed of 300 - 500r / min for 30 - 60min.

10. The preparation method of an antibacterial aromatic water-based ink according to claim 5, characterized in that: In step S1, add the dispersant and deionized water in a dropping manner, and the dropping speed is 1 - 5mL / min.

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