Antibacterial microcapsule printing ink, preparation method thereof and application of antibacterial microcapsule printing ink in cigarette packaging

Abstract

The invention belongs to the technical field of ink for cigarettes, and particularly relates to antibacterial microcapsule ink as well as a preparation method and application thereof in cigarette packaging. The preparation method comprises the following steps: firstly, dispersing chitosan in a glacial acetic acid aqueous solution to obtain a chitosan solution; dissolving gelatin in pure water to obtain a gelatin solution; uniformly mixing span 80 and ocimum gratissimum essential oil to obtain a milk white emulsified solution; adding the gelatin solution and the emulsified solution into the chitosan solution, uniformly mixing, and adjusting the pH value of the solution; and finally, dropwise adding a sodium tripolyphosphate aqueous solution into the solution to carry out an ionic crosslinking reaction, and after the reaction is finished, carrying out freeze drying to obtain the antibacterial microcapsule. And adding the antibacterial microcapsule into an ink system, and uniformly mixing to obtain the antibacterial microcapsule ink. The ocimum gratissimum essential oil is embedded in the chitosan-gelatin solution by using a complex coacervation method to obtain the microcapsule, and the complex coacervation method is mild in reaction condition, low in cost and good in yield. The ink has fragrance and a lasting antibacterial effect, and can be widely applied to cigarette packaging.

Description

Technical Field

[0001] The invention belongs to the technical field of cigarette inks, and particularly relates to an antibacterial microcapsule ink, a preparation method thereof, and application thereof in cigarette packaging. Background Art

[0002] Cigarette ink is a key raw material and auxiliary ingredient in the production of tobacco materials, playing an irreplaceable role in the cigarette manufacturing process. Traditional inks contain large amounts of organic solvents, which are highly harmful to humans and the environment. Furthermore, they are susceptible to environmental fluctuations, and dust and bacteria can cause mold to form during transportation.

[0003] Microcapsules are a process that uses a film-forming material to encapsulate solids, gases, or liquids into tiny particles. The film-forming material serves as the wall material, while the encapsulated material serves as the core material. Microencapsulation technology isolates substances from the surrounding environment, protecting them from external environmental factors such as light, heat, and pressure. It also reduces the volatility of the encapsulated substance and improves its stability.

[0004] Using microencapsulation technology to encapsulate essential oils with antibacterial properties not only preserves the original properties of the substance but also allows the essential oil to be released under appropriate conditions, maintaining the long-term antibacterial effect. Adding the prepared antibacterial microcapsules to the ink preparation process creates a new type of ink with antibacterial properties. This not only maintains the basic properties of the ink, but also reduces material waste and improves safety and stability.

[0005] Patent documentation CN106189497A discloses a kind of slow-release fragrance water-based ink now, the component of this slow-release fragrance water-based ink and weight portion thereof are: aqueous acrylic resin emulsion 35-55 part, ethanol 15-35 part, fragrance slow-release microcapsule 10-20 part, pigment 10-15 part, dispersant 1-2 part, flow agent 0.2-1 part, defoamer 0.2-0.5 part, deionized water 30-55 part: the production technique in this document is simple, the low composite spices embedding rate of production cost is high, can reach 95%, sudden release amount is low, release is stable, spices is wrapped in slow-release capsule, spices is in storage, and is not easily volatile in the process of processing, and printed matter fragrance is lasting, can be applicable to the printed matter that integrates vision, olfactory effect etc. such as magazine, advertisement, postcard, greeting card, calendar, cosmetics and food.But lack in this document the time that the fragrance of ink is lastingly distributed is tracked test.

[0006] Patent document CN109021671A discloses a water-based antibacterial ink and its preparation process. The ink comprises a binder, antibacterial microcapsules, a solvent, a filler, a pigment, and an additive. The mass ratio of the binder, antibacterial microcapsules, solvent, filler, pigment, and additive is 45:30:7:13:3:2. The antibacterial microcapsules are cinnamon essential oil microcapsules encapsulated in β-cyclodextrin, and the binder is a water-based polyurethane acrylate. The preparation process includes the preparation of the antibacterial microcapsules and the water-based antibacterial ink. This document incorporates natural antibacterial substances into antibacterial microcapsules, which not only solves the problem of oil-water insolubility but also slows the release rate of the antibacterial substances, extending the product life of the antibacterial ink and reducing the risk of food packaging safety issues. Using the preparation process described in this document, antibacterial microcapsules with a high encapsulation rate are prepared, further enhancing the antibacterial effect of the ink. However, this document does not provide a comprehensive evaluation of the ink's long-lasting antibacterial properties.

[0007] Therefore, how to apply microcapsule technology to cigarette inks and prepare inks with long-lasting antibacterial properties is an urgent problem to be solved. Summary of the Invention

[0008] Based on this, the present invention aims to provide an antibacterial microcapsule ink with long-lasting antibacterial properties. When applied to cigarette packaging, this ink can reduce odor, enhance aroma, and provide mildew resistance, thereby increasing the novelty of the cigarette product.

[0009] The present invention also provides a method for preparing the antibacterial microcapsule ink, wherein the antibacterial microcapsules are prepared by a complex coacervation method, the raw material and production equipment costs are low, and the preparation process is simple and easy to promote.

[0010] To achieve the above object, the present invention adopts the following technical solutions: The present invention provides a method for preparing an antibacterial microcapsule ink, which is based on a complex coacervation method and comprises the following steps: S1, dispersing chitosan in a glacial acetic acid aqueous solution with a mass fraction of 1% to 1.3% to obtain a transparent and clear chitosan solution; S2, dissolving gelatin in pure water at 50±1°C to obtain a gelatin solution; mixing Span 80 and clove basil essential oil at 25±5°C to obtain a milky white emulsified solution; S3, first adding the gelatin solution described in S2 to the chitosan solution described in S1 and mixing to form solution A, adjusting the pH of solution A to 6.0-6.5 to obtain solution B; then adding the milky white emulsified solution described in S2 to solution B and mixing to obtain solution C; S4, adding a 4% to 4.5% by mass sodium tripolyphosphate aqueous solution dropwise to the solution C described in S3 at 25±5°C for 10 to 20 minutes of ionic crosslinking reaction, and freeze-drying after the reaction to obtain antibacterial microcapsules; S5, adding the antibacterial microcapsules into the ink system and mixing evenly to obtain the antibacterial microcapsule ink.

[0011] Furthermore, the mass addition amount of the chitosan in S1 is 0.16-0.2 parts, and the mass addition amount of the glacial acetic acid aqueous solution is 90-100 parts; and the dispersion process is: ultrasonic dispersion for 30-50 minutes.

[0012] Furthermore, the mass amount of gelatin added in S2 is 0.08-0.12 parts, and the mass amount of pure water added is 18-20 parts; the temperature of the gelatin solution is maintained at 50±1°C; the mass amount of Span 80 added is 0.34-0.40 parts, and the mass amount of clove basil essential oil added is 0.38-0.42 parts; the mixing process is: stirring with a magnetic stirrer, controlling the stirrer speed to 500-1500 rpm, and stirring for 2-4 hours.

[0013] Furthermore, the amount of the gelatin solution added in S3 is 18 to 20 parts by mass; the amount of the emulsified solution added is 0.72 to 0.82 parts by mass; and the amount of the chitosan solution added is 90 to 100 parts by mass; the gelatin solution is first added to the chitosan solution and ultrasonically dispersed for 4 to 6 minutes, and then the emulsified solution is added, the stirrer speed is controlled at 500±20 r / min, and stirring is carried out for 0.5 to 1.5 hours to uniformly diffuse it in the chitosan solution.

[0014] Furthermore, the mass fraction of the sodium tripolyphosphate aqueous solution added in S4 is 0.8 to 1 part; and the freeze-drying time is 24 to 48 hours.

[0015] Furthermore, the ink system described in S5 includes pigments, dispersants, deionized water, cosolvents, water-based acrylic resins, Sban 80 and additives, and the additives include thickeners, leveling agents, defoaming agents and preservatives; the pigments include organic pigments or inorganic pigments, the dispersants include polyacrylate compounds, the cosolvents include ethanol, the thickeners include hydrocarbon compounds, the leveling agents include acrylic leveling agents, the defoaming agents include silicone compounds, and the preservatives include isothiazolinone preservatives.

[0016] Preferably, the pigment is TS-black-02W (pure black) inorganic pigment; the dispersant is sodium polyacrylate, the thickener is hydroxyethyl cellulose, the leveling agent is polyurethane, the defoamer is emulsified silicone oil, and the preservative is 1-2-benzisothiazolin-3-one (BIT).

[0017] Furthermore, S5 includes the following steps: S51, first mixing the pigment, dispersant and deionized water at a stirring speed of 500±50 r / min, then adding a cosolvent, increasing the stirring speed to 1500±50 r / min and mixing to obtain a slurry; S52, adding the water-based acrylic resin to the slurry in S51 and mixing evenly, then adding Span 80, additives and antibacterial microcapsules, and homogenizing to obtain antibacterial microcapsule ink.

[0018] Furthermore, the mass percentages of the raw materials are: dispersant 1%-2%, deionized water 25%-30%, pigment 10%-25%, cosolvent 5%-8%, water-based acrylic resin 30%-35%, antibacterial microcapsules 10%-15%, Span 80 2%-5%, and additives 2%-4%.

[0019] The present invention further provides an antibacterial microcapsule ink prepared by the above-mentioned preparation method of the antibacterial microcapsule ink.

[0020] Finally, the present invention provides an application of the antibacterial microcapsule ink on cigarette packaging boxes.

[0021] The beneficial effects of the present invention are: The present invention provides a method for preparing antibacterial microcapsule inks, employing a complex coacervation process to allow chitosan and gelatin to interact and form a stable composite capsule wall. Chitosan, a cationic polyelectrolyte, is positively charged under acidic conditions. During complex coacervation, the pH is adjusted to above the isoelectric point of gelatin, giving it a negative charge. This negative charge then binds to the positively charged chitosan through electrostatic attraction, forming a coacervate that encapsulates the core material.

[0022] 2. The present invention provides a method for preparing an antibacterial microcapsule ink. By thoroughly mixing Span 80 with basil essential oil and then adding the mixture to a chitosan and gelatin solution, the reaction time is significantly shortened. Basil essential oil is then encapsulated in a chitosan-gelatin solution to form chemically stable antibacterial microcapsules, which are then applied to the ink system used in cigarette packaging. Basil essential oil is a natural, organic antibacterial substance with a strong inhibitory effect against bacteria and fungi, and is non-toxic to humans and the environment.

[0023] 3. The preparation method of the antibacterial microcapsule ink provided by the present invention, in which sodium tripolyphosphate in the raw material serves as a multivalent anionic crosslinking agent, forms a three-dimensional network with positively charged chitosan or insufficiently cross-linked gelatin through electrostatic interaction, which can significantly enhance the mechanical strength and thermal stability of the capsule wall, thereby delaying the release of the core material and significantly improving the long-lasting antibacterial effect.

[0024] 4. The preparation method of the antibacterial microcapsule ink provided by the present invention has mild reaction conditions of the complex coacervation method, which causes little damage to the quality of the embedded fragrance during the processing. It does not require professional equipment, has low cost, high efficiency, and good yield. The obtained microcapsules have relatively uniform particle size and strong chemical stability.

[0025] 5. The antibacterial microcapsule ink provided by the present invention has fragrance and antibacterial effects. Its application in the cigarette package printing process can not only reduce the risk of cigarettes being contaminated by bacteria during transportation, thereby reducing the loss of cigarette products during storage and transportation, but also improve brand competitiveness, enhance the characteristics of cigarette brands, and enhance novelty. DETAILED DESCRIPTION

[0026] The technical solutions in the embodiments of the present invention are described clearly and completely below. The embodiments mentioned are all implemented based on the technical solutions of the present invention, and detailed implementation processes are given. However, it should be noted that the scope of protection of the present invention is not limited to the following embodiments.

[0027] The following examples provide detailed examples of the technical solutions of the present invention. The experimental methods used in the following experimental examples are conventional methods unless otherwise specified; the materials and reagents used are commercially available reagents and materials unless otherwise specified. Example 1

[0028] This embodiment provides an antibacterial microcapsule ink, the components and percentages of which are: 35% water-based acrylic resin, 8% ethanol, 10% TS-black-02W (pure black) pigment, 10% antibacterial microcapsules, 28% deionized water, 5% Span 80, 1.5% dispersant sodium polyacrylate, 0.5% thickener hydroxyethyl cellulose, 0.4% leveling agent polyurethane, 0.6% defoaming agent emulsified silicone oil, and 1% preservative BIT.

[0029] The preparation process and dosage of antibacterial microcapsule ink are as follows: (1) Weigh 0.18 g of chitosan and add 100 mL of a 1% glacial acetic acid aqueous solution. Ultrasonic dispersion was performed for 40 min to form a clear and transparent chitosan solution. The solution was then stored for later use.

[0030] (2) Weigh 0.1 g of gelatin and dissolve it in 15 g of pure water at 50°C to obtain a gelatin solution. Keep it at 50°C for later use.

[0031] (3) Weigh 0.36 g of emulsifier Span 80 and 0.42 g of basil essential oil and stir them on a magnetic stirrer at 1000 r / min at 25±5°C for 2 h to uniformly emulsify and obtain a milky white emulsified solution. Add the gelatin solution to the chitosan solution prepared above, adjust the solution pH to 6.5, and mix by ultrasonication for 5 min. Then, add the milky white emulsified solution to the above solution and stir at 500 r / min for 1 h.

[0032] (4) At 25±5℃, weigh 0.08 g of a prepared 4% sodium tripolyphosphate aqueous solution and slowly add it dropwise to the solution. Under stirring conditions of 500 r / min, carry out ionic crosslinking reaction for 15 min. After the crosslinking reaction is completed, freeze-dry the solution for 24 h to prepare antibacterial microcapsules.

[0033] (5) Add the pigment, dispersant, and deionized water to a container and stir at a low speed of 500 r / min until uniformly wetted. Then, add ethanol as a cosolvent and increase the speed to 1500 r / min and stir to form a slurry. Then, add the water-based acrylic resin to the slurry and stir until mixed. Then, add Span 80, additives, and the prepared antibacterial microcapsules and homogenize to obtain the antibacterial microcapsule ink. Example 2

[0034] This embodiment provides an antibacterial microcapsule ink, the components and percentages of which are: 35% water-based acrylic resin, 8% ethanol, 9% TS-black-02W (pure black) pigment, 12% antibacterial microcapsules, 27% deionized water, 5% Span 80, 1.5% dispersant sodium polyacrylate, 0.5% thickener hydroxyethyl cellulose, 0.4% leveling agent polyurethane, 0.6% defoaming agent emulsified silicone oil, and 1% preservative BIT.

[0035] The preparation process and dosage of antibacterial microcapsule ink are as follows: (1) Weigh 0.18 g of chitosan and add 100 mL of a 1% glacial acetic acid aqueous solution. Ultrasonic dispersion was performed for 40 min to form a clear and transparent chitosan solution. The solution was then stored for later use.

[0036] (2) Weigh 0.1 g of gelatin and dissolve it in 15 g of pure water at 50°C to obtain a gelatin solution. Keep it at 50°C for later use.

[0037] (3) Weigh 0.36 g of emulsifier Span 80 and 0.42 g of basil essential oil and stir them on a magnetic stirrer at 1000 r / min at 25±5°C for 2 h to uniformly emulsify and obtain a milky white emulsified solution. Add the gelatin solution to the chitosan solution prepared above, adjust the solution pH to 6.5, and mix by ultrasonication for 5 min. Then, add the milky white emulsified solution to the above solution and stir at 500 r / min for 1 h.

[0038] (4) At 25±5℃, weigh 0.08 g of a prepared 4% sodium tripolyphosphate aqueous solution and slowly add it dropwise to the solution. Under stirring conditions of 500 r / min, carry out ionic crosslinking reaction for 15 min. After the crosslinking reaction is completed, freeze-dry the solution for 24 h to prepare antibacterial microcapsules.

[0039] (5) Add the pigment, dispersant, and deionized water to a container and stir at a low speed of 500 r / min until uniformly wetted. Then, add ethanol as a cosolvent and increase the speed to 1500 r / min and stir to form a slurry. Then, add the water-based acrylic resin to the slurry and stir until mixed. Then, add Span 80, additives, and the prepared antibacterial microcapsules and homogenize to obtain the antibacterial microcapsule ink. Example 3

[0040] This embodiment provides an antibacterial microcapsule ink, the components and percentages of which are: 35% water-based acrylic resin, 8% ethanol, 10% TS-black-02W (pure black) pigment, 10% antibacterial microcapsules, 28% deionized water, 5% Span 80, 1.5% dispersant sodium polyacrylate, 0.5% thickener hydroxyethyl cellulose, 0.4% leveling agent polyurethane, 0.6% defoaming agent emulsified silicone oil, and 1% preservative BIT.

[0041] The preparation process and dosage of antibacterial microcapsule ink are as follows: (1) Weigh 0.22 g of chitosan and add 100 mL of a 1% glacial acetic acid aqueous solution. Ultrasonic dispersion was performed for 40 min to form a clear and transparent chitosan solution. The solution was then stored for later use.

[0042] (2) Weigh 0.1 g of gelatin and dissolve it in pure water at 50°C to obtain a gelatin solution. Keep it at 50°C for later use.

[0043] (3) Weigh 0.36 g of emulsifier Span 80 and 0.42 g of basil essential oil and stir them on a magnetic stirrer at 1000 r / min at 25±5°C for 2 h to uniformly emulsify and obtain a milky white emulsified solution. Add the gelatin solution to the chitosan solution prepared above, adjust the solution pH to 6.5, and mix by ultrasonication for 5 min. Then, add the milky white emulsified solution to the above solution and stir at 500 r / min for 1 h.

[0044] (4) At 25±5℃, weigh 0.08 g of a prepared 4% sodium tripolyphosphate aqueous solution and slowly add it dropwise to the solution. Under stirring conditions of 500 r / min, carry out ionic crosslinking reaction for 15 min. After the crosslinking reaction is completed, freeze-dry the solution for 24 h to prepare antibacterial microcapsules.

[0045] (5) Add the pigment, dispersant, and deionized water to a container and stir at a low speed of 500 r / min until uniformly wetted. Then, add ethanol as a cosolvent and increase the speed to 1500 r / min and stir to form a slurry. Then, add the water-based acrylic resin to the slurry and stir until mixed. Then, add Span 80, additives, and the prepared antibacterial microcapsules and homogenize to obtain the antibacterial microcapsule ink. Example 4

[0046] This embodiment provides an antibacterial microcapsule ink, the components and percentages of which are: 35% water-based acrylic resin, 8% ethanol, 10% TS-black-02W (pure black) pigment, 10% antibacterial microcapsules, 28% deionized water, 5% Span 80, 1.5% dispersant sodium polyacrylate, 0.5% thickener hydroxyethyl cellulose, 0.4% leveling agent polyurethane, 0.6% defoaming agent emulsified silicone oil, and 1% preservative BIT.

[0047] The preparation process and dosage of antibacterial microcapsule ink are as follows: (1) Weigh 0.18 g of chitosan and add it to 100 mL of a 1% glacial acetic acid aqueous solution. Ultrasonic disperse the solution for 40 min to form a clear and transparent chitosan solution. Store the solution for later use.

[0048] (2) Weigh 0.1 g of gelatin and dissolve it in pure water at 50°C to obtain a gelatin solution. Keep it at 50°C for later use.

[0049] (3) Weigh 0.36 g of emulsifier Span 80 and 0.46 g of basil essential oil and stir them on a magnetic stirrer at 1000 r / min at 25±5°C for 2 h to uniformly emulsify and obtain a milky white emulsified solution. Add the gelatin solution to the chitosan solution prepared above, adjust the solution pH to 6.5, and mix it by ultrasonication for 5 min. Then, add the milky white emulsified solution to the above solution and stir at 500 r / min for 1 h.

[0050] (4) At 25±5℃, weigh 0.08 g of a prepared 4% sodium tripolyphosphate aqueous solution and slowly add it dropwise to the solution. Under stirring conditions of 500 r / min, carry out ionic crosslinking reaction for 15 min. After the crosslinking reaction is completed, freeze-dry the solution for 24 h to prepare antibacterial microcapsules.

[0051] (5) Add the pigment, dispersant, and deionized water to a container and stir at a low speed of 500 r / min until uniformly wetted. Then, add ethanol as a cosolvent and increase the speed to 1500 r / min and stir to form a slurry. Then, add the water-based acrylic resin to the slurry and stir until mixed. Then, add Span 80, additives, and the prepared antibacterial microcapsules and homogenize to obtain the antibacterial microcapsule ink. Example 5

[0052] This embodiment provides an antibacterial microcapsule ink, the components and percentages of which are: 35% water-based acrylic resin, 8% ethanol, 10% TS-black-02W (pure black) pigment, 10% antibacterial microcapsules, 28% deionized water, 5% Span 80, 1.5% dispersant sodium polyacrylate, 0.5% thickener hydroxyethyl cellulose, 0.4% leveling agent polyurethane, 0.6% defoaming agent emulsified silicone oil, and 1% preservative BIT.

[0053] The preparation process and dosage of antibacterial microcapsule ink are as follows: (1) Weigh 0.18 g of chitosan and add it to 100 mL of a 1% glacial acetic acid aqueous solution. Ultrasonic disperse the solution for 40 min to form a clear and transparent chitosan solution. Store the solution for later use.

[0054] (2) Weigh 0.1 g of gelatin and dissolve it in pure water at 50°C to obtain a gelatin solution. Keep it at 50°C for later use.

[0055] (3) Weigh 0.42 g of emulsifier Span 80 and 0.42 g of clove basil essential oil, stir them on a magnetic stirrer at 1000 r / min at 25±5°C for 2 h to uniformly emulsify and obtain a milky white emulsified solution. Add the gelatin solution to the chitosan solution prepared above, adjust the solution pH to 6.5, and mix it by ultrasonication for 5 min. Then, add the milky white emulsified solution to the above solution and stir at 500 r / min for 1 h.

[0056] (4) At 25±5℃, weigh 0.08 g of a prepared 4% sodium tripolyphosphate aqueous solution and slowly add it dropwise to the solution. Under stirring conditions of 500 r / min, carry out ionic crosslinking reaction for 15 min. After the crosslinking reaction is completed, freeze-dry the solution for 24 h to prepare antibacterial microcapsules.

[0057] (5) Add the pigment, dispersant, and deionized water to a container and stir at a low speed of 500 r / min until uniformly wetted. Then, add ethanol as a cosolvent and increase the speed to 1500 r / min and stir to form a slurry. Then, add the water-based acrylic resin to the slurry and stir until mixed. Then, add Span 80, additives, and the prepared antibacterial microcapsules and homogenize to obtain the antibacterial microcapsule ink.

[0058] Comparative Example 1 The difference between this comparative example and Example 1 is that, among the components of the ink, the percentage of antibacterial microcapsules is 8%, and the percentage of deionized water is 30%.

[0059] Comparative Example 2 The difference between this comparative example and Example 1 is that, among the components of the ink, the percentage of antibacterial microcapsules is 3%, and the percentage of deionized water is 33%.

[0060] Comparative Example 3 The difference between this comparative example and Example 1 is that clove basil essential oil is directly added as an antibacterial agent during the ink preparation process. Specifically: This comparative example provides an ink, the components of which and their percentages are: 35% water-based acrylic resin, 8% ethanol, 10% pigment TS-black-02W (pure black), 10% clove basil essential oil, 28% deionized water, 5% Span 80, 1.5% dispersant polyacrylic acid, 0.5% thickener hydroxyethyl cellulose, 0.4% leveling agent polyurethane, 0.6% defoaming agent emulsified silicone oil, and 1% preservative BIT.

[0061] Comparative Example 4 The difference between this comparative example and Example 1 is that no antibacterial microcapsules were prepared and no antibacterial agent was added during the ink preparation process. This comparative example provides an ink, the components of which and their percentages are: 45% water-based acrylic resin, 8% ethanol, 10% pigment TS-black-02W (pure black), 28% deionized water, 5% Span 80, 1.5% dispersant sodium polyacrylate, 0.5% thickener hydroxyethyl cellulose, 0.4% leveling agent polyurethane, 0.6% defoaming agent emulsified silicone oil, and 1% preservative BIT.

[0062] The ink preparation process is as follows: pigment, dispersant, and deionized water are added to a container and stirred at 500 rpm until uniformly moistened. Ethanol as a cosolvent is then added, and the speed is increased to 1500 rpm, stirring to form a slurry. A water-based acrylic resin is then added to the slurry and stirred until uniformly mixed. Finally, Span 80 and additives are added and homogenized to produce the ink.

[0063] Comparative Example 5 This comparative example directly uses commercially available ink.

[0064] Comparative Example 6 The difference between this comparative example and Example 1 is that no gelatin solution was added.

[0065] The following tests and analyses were conducted on the embedding rates of the various microcapsules prepared above and the antibacterial properties of the inks.

[0066] (1) Antibacterial microcapsule embedding rate test The embedding efficiency is one of the indicators for evaluating the effectiveness of microcapsule preparation. The embedding efficiency of the prepared antibacterial microcapsules is calculated using the formula E = (1 - m1 / m2) * 100%, where m1 is the mass of unencapsulated oil and m2 is the mass of total oil. The embedding efficiency of the antibacterial microcapsules prepared in Examples 1, 3, 4, and 5, as well as Comparative Example 6, was measured.

[0067] Determine the mass of unentrapped oil m1: Take 10 g of microcapsules and put them into a beaker. Shake with 50 mL of petroleum ether for 5 minutes and filter into a flask. The mass is recorded as m 瓶 , re-measure 150 mL of petroleum ether, add it to the beaker several times to rinse, shake for 5 minutes, filter it into the flask, connect it to the rotary evaporator for evaporation, and then place the flask in an oven at 50℃ for 5 minutes to dry it. The mass is m 总 , unembedded oil mass m1=m 总 -m 瓶 .

[0068] Determination of total oil mass m2: Weigh 10 g of microcapsules and add 80 mL of n-hexane and sonicate for 40 min. Filter the solution into a flask and wash the filter residue with 120 mL of n-hexane. Connect the two filtrates to a rotary evaporator for evaporation and then dry the flask in an oven at 50°C to obtain the total oil mass m2.

[0069] The results of measurement and calculation show that the embedding efficiency of the antibacterial microcapsules in Example 1 is 87.68%, the embedding efficiency of the antibacterial microcapsules in Example 3 is 77.41%, the embedding efficiency of the antibacterial microcapsules in Example 4 is 76.81%, the embedding efficiency of the antibacterial microcapsules in Example 5 is 72.39%, and the embedding efficiency of the antibacterial microcapsules in Comparative Example 6 is 73.61%. This is shown in Table 1 below:

[0070] From the data of the embedding rate, it can be seen that as the wall material content, core material content and emulsifier content increase, the embedding rate of the prepared microcapsules decreases. Comparing Example 1 with Example 3, it can be found that the wall material, i.e., chitosan content, increases, resulting in the appearance of soluble gel, causing the microcapsules to aggregate and condense, and the embedding rate decreases. Comparing Example 1 with Example 4, the increase in core material content may cause the capsule wall for embedding essential oils to be too thin, making the microcapsules easily broken, or the wall material content is relatively low, which is not enough to embed the essential oils, resulting in a decrease in the embedding rate. Comparing Example 1 with Example 5, the emulsifier content increases, and the attraction of its cross-linking effect may affect the combination of the wall material and the core material, resulting in a decrease in the embedding rate. Comparing Example 1 with Comparative Example 6, it can be seen that the embedding rate of the microcapsules prepared using chitosan-gelatin as the wall material is much higher than that using only chitosan wall material.

[0071] (2) Antibacterial performance test of antibacterial microcapsule ink Antibacterial Performance Testing: According to the national standard GB-T21866, the antibacterial microcapsule inks prepared in Examples 1-5 and the ink samples in Comparative Examples 1-6 were applied to a sample. The ink was applied twice, with the first coat applied after the surface was dry. The sample should be flat and free of contamination. Before testing, the sample should be sterilized under ultraviolet light in a clean bench.

[0072] The test bacteria species were Staphylococcus aureus, Escherichia coli, and Penicillium. 0.4 mL to 0.5 mL of bacterial solution was dripped onto various ink samples. A film was applied to ensure uniform contact between the bacteria and the samples. After incubation for a period of time, the number of viable bacteria on the samples was determined, and the antibacterial rate was calculated. The samples were divided into two groups: initial samples and samples that had been stored at room temperature and pressure for six months. The test results are shown in Table 2 below.

[0073] The test results in the table above demonstrate that the antibacterial microcapsule ink prepared using the method for preparing the antibacterial microcapsule ink provided by the present invention exhibits excellent antibacterial properties. Comparing Examples 1 and 2 with Comparative Examples 1 and 2 reveals that decreasing the amount of microcapsules added deteriorates the antibacterial efficacy of the resulting inks, while increasing the microcapsule content enhances their inhibitory activity against bacteria and fungi. Examples 1 and 3-5 demonstrate that varying the wall material, core material, and emulsifier content all influence microcapsule preparation, thereby altering ink properties and affecting their resistance to bacteria. Comparative Example 3 demonstrates that directly adding essential oil to the ink does not significantly enhance the antibacterial effect and can even affect the ink's inherent properties. Comparing Example 1 with Comparative Example 6 reveals that the antibacterial performance of the microcapsule ink prepared using the chitosan-gelatin-sodium tripolyphosphate system is significantly superior to that of the chitosan-sodium tripolyphosphate system, demonstrating that the three components synergistically enhance the strength and stability of the capsule wall. Overall, the antibacterial properties of the antibacterial microcapsule inks in the examples are significantly superior to those in the comparative examples.

[0074] By comparing the initial sample group and the sample group stored at room temperature and pressure for 6 months, the antibacterial property of the ink in the comparative example decreased significantly after 6 months of storage, while the antibacterial property of the antibacterial microcapsule ink in the embodiment remained above 90%, indicating that the microcapsules can indeed delay the release of clove basil essential oil during storage and make the antibacterial effect of the ink last for a long time.

[0075] The above description of the disclosed embodiments will enable one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention is not limited to the embodiments shown herein, but is to be construed in the widest manner consistent with the principles and novel features disclosed herein.

Claims

1. A method for preparing an antibacterial microcapsule ink, characterized in that: The steps include: S1, dispersing chitosan in a glacial acetic acid aqueous solution with a mass fraction of 1% to 1.3% to obtain a transparent and clear chitosan solution; S2, dissolving gelatin in pure water at 50±1°C to obtain a gelatin solution; mixing Span 80 and clove basil essential oil at 25±5°C to obtain a milky white emulsified solution; S3, first adding the gelatin solution described in S2 to the chitosan solution described in S1 and mixing to form solution A, adjusting the pH of solution A to 6.0-6.5 to obtain solution B; then adding the milky white emulsified solution described in S2 to solution B and mixing to obtain solution C; S4, adding a 4% to 4.5% by mass sodium tripolyphosphate aqueous solution dropwise to the solution C described in S3 at 25±5°C for 10 to 20 minutes of ionic crosslinking reaction, and freeze-drying after the reaction to obtain antibacterial microcapsules; S5, adding the antibacterial microcapsules into the ink system and mixing evenly to obtain the antibacterial microcapsule ink.

2. The method for preparing the antibacterial microcapsule ink according to claim 1, wherein: The mass fraction of chitosan added in S1 is 0.16-0.2 parts, and the mass fraction of glacial acetic acid aqueous solution added is 90-100 parts; the dispersion process is: ultrasonic dispersion for 30-50 minutes.

3. The method for preparing the antibacterial microcapsule ink according to claim 1, wherein: The amount of gelatin added in S2 is 0.08 to 0.12 parts by mass, and the amount of pure water added is 18 to 20 parts by mass; the temperature of the gelatin solution is maintained at 50±1°C; the amount of Span 80 added is 0.34 to 0.40 parts by mass, and the amount of clove basil essential oil added is 0.38 to 0.42 parts by mass; the mixing process is: controlling the stirrer speed to 500 to 1500 rpm / min and stirring for 2 to 4 hours.

4. The method for preparing the antibacterial microcapsule ink according to claim 1, wherein: The gelatin solution added in S3 is 18 to 20 parts by mass; the emulsified solution added is 0.72 to 0.82 parts by mass; and the chitosan solution added is 90 to 100 parts by mass. The gelatin solution is first added to the chitosan solution and ultrasonically dispersed for 4 to 6 minutes, and then the emulsified solution is added. The stirrer speed is controlled at 500 ± 20 r / min and stirred for 0.5 to 1.5 hours.

5. The method for preparing the antibacterial microcapsule ink according to claim 1, wherein: The amount of the sodium tripolyphosphate aqueous solution added in S4 is 0.8 to 1 part by mass; and the freeze-drying time is 24 to 48 hours.

6. The method for preparing the antibacterial microcapsule ink according to claim 1, wherein: The ink system described in S5 includes pigment, dispersant, deionized water, cosolvent, water-based acrylic resin, Span 80 and additives; the additives include thickener, leveling agent, defoaming agent and preservative; the dispersant includes polyacrylate compound.

7. The method for preparing the antibacterial microcapsule ink according to claim 6, wherein: S5 includes the following steps: S51, mixing the pigment, dispersant and deionized water, and then adding a co-solvent and mixing to obtain a slurry; S52, adding the water-based acrylic resin to the slurry in S51 and mixing evenly, then adding Span 80, additives and antibacterial microcapsules, and homogenizing to obtain antibacterial microcapsule ink.

8. The method for preparing the antibacterial microcapsule ink according to claim 7, wherein: The mass percentages of the raw materials are: dispersant 1%-2%, deionized water 25%-30%, pigment 10%-25%, cosolvent 5%-8%, water-based acrylic resin 30%-35%, antibacterial microcapsule 10%-15%, Span 80 2%-5%, and additives 2%-4%.

9. An antibacterial microcapsule ink prepared by the method for preparing the antibacterial microcapsule ink according to any one of claims 1 to 8.

10. Use of the antibacterial microcapsule ink according to claim 9 on cigarette packaging.

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