UV ink for cigarette packaging paper and printing process thereof

Abstract

The present invention relates to the field of inks, and in particular to a UV ink for cigarette wrapping paper and a printing process thereof. The UV ink comprises, calculated by weight, 50-70 parts of polyurethane acrylate, 12-24 parts of bisphenol A epoxy acrylate, 15-30 parts of bifunctional acrylate, 4-18 parts of a filler modifier, 0.1-10 parts of a pigment, 0.1-1 parts of a dispersant, 0.1-1 parts of a defoamer, and 2.7-5.4 parts of a photoinitiator. The UV resin used in the present invention is a mixture of polyurethane acrylate, bisphenol A epoxy acrylate, and bifunctional acrylate; the filler is a filler modifier prepared using allophane nanotubes; and a portion of pigment and additives are also added. The prepared UV ink has high gloss and good water resistance, and also has excellent wear resistance and corrosion resistance.

Description

Technical Field

[0001] The present invention relates to the field of inks, and in particular to UV ink for cigarette packaging paper and a printing process thereof. Background Art

[0002] Wrapping paper, typically made of paper, is currently the most widely used packaging material. With the continued growth of the cigarette industry in recent years, its use has been increasing. To clearly display product information, wrapping paper is often printed with fonts, patterns, and other materials to visually convey the contents of the wrapper. As the material used to create graphic information, ink plays a crucial role in the printing industry, directly determining the color and clarity of images on the wrapping paper. Ink is generally composed of pigments, binders, and fillers. Pigments impart a variety of hues to printed products, binders enable the pigments to adhere to the substrate, and fillers impart appropriate properties to the ink, ensuring its suitability for various printing processes.

[0003] UV inks, a rapidly developing environmentally friendly ink, have rapidly captured the market with their instant curing properties, lack of volatile solvents, and ease of application. UV inks include specialty packaging inks such as UV matte, UV ice flower, UV foaming, UV wrinkle, UV embossing, UV refractive, UV gem, UV light-fixing inks, and UV varnishes. UV inks are applied via screen printing to substrates with a metallic, mirror-like finish. After exposure to UV light, they create a unique visual effect that exudes elegance, sophistication, and luxury. These products are primarily used for high-end, exquisite packaging for tobacco, alcohol, cosmetics, health products, food, and pharmaceuticals. While UV inks offer excellent gloss, they suffer from relatively poor water resistance, potentially causing discoloration or fading in humid environments. Furthermore, the films formed after curing can exhibit limited physical properties, such as scratch and chemical resistance. These limitations limit their application in cigarette packaging. Summary of the Invention

[0004] In view of the problems existing in the prior art, the present invention aims to provide a UV ink for cigarette packaging paper and a printing process thereof.

[0005] The purpose of the present invention is achieved by adopting the following technical solutions:

[0006] In a first aspect, the present invention provides a UV ink for cigarette packaging paper, which comprises, calculated by weight:

[0007] 50-70 parts of polyurethane acrylate, 12-24 parts of bisphenol A epoxy acrylate, 15-30 parts of difunctional acrylate, 4-18 parts of filler modifier, 0.1-10 parts of pigment, 0.1-1 parts of dispersant, 0.1-1 parts of defoamer and 2.7-5.4 parts of photoinitiator.

[0008] Preferably, the brand of the polyurethane acrylate (PUA) is one of UV-1230, UV-1990, and UV-1205.

[0009] Preferably, the brand of the bisphenol A epoxy acrylate (EA) is one of Covestro Agisyn 1010-A80, Covestro Agisyn 1030, and Covestro Agisyn 1050.

[0010] Preferably, the bifunctional acrylate is a mixture of diethylene glycol diacrylate, triethylene glycol diacrylate and 1,6-hexanediol diacrylate, and the mass ratio of diethylene glycol diacrylate, triethylene glycol diacrylate and 1,6-hexanediol diacrylate is 1-5:2-6:1-5.

[0011] Preferably, the pigment is an organic pigment, including at least one of phthalocyanine red, phthalocyanine blue, phthalocyanine green, permanent yellow, and permanent violet.

[0012] Preferably, the dispersant is at least one of TEGO-655, TEGO-688, TEGO-685, and TEGO-755W.

[0013] Preferably, the defoaming agent is at least one of BYK-085, BYK-1794, BYK-012, and BYK-024.

[0014] Preferably, the photoinitiator is at least one of photoinitiator TPO-L (ethyl 2,4,6-trimethylbenzoylphenylphosphonate), photoinitiator 1173 (2-hydroxy-2-methyl-1-phenyl-1-propanone), and photoinitiator 184 (hydroxycyclohexane phenone).

[0015] Preferably, the preparation method of the filling modifier comprises:

[0016] S1. Mixing hydrous allophane nanotubes with anhydrous ethanol, adding 3-aminopropyltriethoxysilane, and then refluxing at 50-70° C. for 3-10 hours. After the treatment, centrifuging in a centrifuge to collect the precipitate, then rinsing the precipitate three times with anhydrous ethanol and drying it in a vacuum oven to obtain ammoniated hydrous allophane nanotubes;

[0017] S2. Add 3-mercaptobenzoic acid to N,N-dimethylformamide and stir thoroughly until dissolved. Then add condensing agent EDCl (1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride) and stir at room temperature for 0.5-1.5h. Then add activator DMAP (4-dimethylaminopyridine) and stir again for 0.5-1.5h. Then add amination-modified allophane nanotubes and stir to disperse them uniformly. Then stir at room temperature for 20-30h. After the reaction is completed, remove the solvent under reduced pressure, collect the solid, rinse it three times with anhydrous ethanol, and then dry it in a vacuum oven to obtain modified allophane nanotubes.

[0018] S3. Dissolve allyl phenyl ether in N,N-dimethylformamide, then add modified allophane nanotubes, and after uniform dispersion, introduce nitrogen as a protective gas, add a photoinitiator, and stir the reaction under ultraviolet light for 1-2 hours. After the reaction is completed, remove the solvent under reduced pressure, collect the solid, rinse it three times with anhydrous ethanol, and vacuum dry it to obtain a filling modifier.

[0019] Preferably, in S1, the particle size of the allophane nanotubes is 100±10 nm, the SiO2 content is greater than 28%, the Al2O3 content is greater than 56%, and the density is 1.86-1.88 g / cm 3 , purchased from Shandong Qiying Nanotechnology Co., Ltd.

[0020] Preferably, in S1, the mass-to-volume ratio of the allophane nanotubes, 3-aminopropyltriethoxysilane and anhydrous ethanol is 1 g: (0.3-0.6) g: (15-35) mL.

[0021] Preferably, in S2, the mass volume ratio of the amino-hydrated allophane nanotubes, 3-mercaptobenzoic acid, condensing agent EDCl, activating agent DMAP and N,N-dimethylformamide is 1 g:(0.31-0.62) g:(0.4-0.8) g:(0.24-0.48) g:(10-20) mL.

[0022] Preferably, in S3, the mass volume ratio of the modified allophane nanotubes, allyl phenyl ether, and N,N-dimethylformamide is 1 g: (0.26-0.52) g: (30-50) mL.

[0023] Preferably, in S3, the irradiation intensity of the ultraviolet light is 1.2-2.4 mw / cm 2 , the wavelength is 280-400nm.

[0024] Preferably, in S3, the photoinitiator is benzoin dimethyl ether or benzoin diethyl ether, and the amount used is 2%-10% of the mass of the modified allophane nanotubes.

[0025] In a second aspect, the present invention provides a method for preparing UV ink for cigarette packaging paper, comprising the following steps:

[0026] Step 1: firstly mix polyurethane acrylate, bisphenol A epoxy acrylate, and difunctional acrylate, and stir thoroughly to obtain a mixed resin;

[0027] Step 2: adding a filler modifier, a pigment, a dispersant, and a defoamer to the mixed resin, then grinding the mixture on a three-roll mill and passing it through a 100-300 mesh sieve to obtain a mixed liquid;

[0028] Step 3: Add a photoinitiator to the mixed liquid, stir thoroughly and evenly to obtain UV ink for cigarette packaging paper.

[0029] The beneficial effects of the present invention are:

[0030] 1. The present invention prepares a UV ink suitable for cigarette packaging paper. The UV resin used is a mixture of polyurethane acrylate, bisphenol A epoxy acrylate, and difunctional acrylate. The filler is a filler modifier prepared using hydrophobic nanotubes. At the same time, some pigments and additives are added. The prepared UV ink not only has high gloss and good water resistance, but also has excellent wear resistance and corrosion resistance.

[0031] 2. The modification of the present invention to the existing UV ink is that a variety of acrylates are used as UV resins, combining the advantages of multiple raw materials to enhance the strength, toughness and adhesion performance of the UV ink.

[0032] 3. The present invention improves existing UV inks by using a filler modified from allophane nanotubes. Allophane nanotubes have a large specific surface area, excellent adsorption properties, and surface activity. The present invention utilizes these properties by first subjecting the allophane nanotubes to aminosilanization treatment, then reacting them with 3-mercaptobenzoic acid containing a carboxyl group to form an amino-carboxyl catalytic condensation reaction, and finally reacting them with allylphenyl ether containing a double bond to form a mercapto-double bond click chemistry reaction. The resulting modified material is the filler modifier.

[0033] 3. In the modification of allophane nanotubes in the present invention, groups such as phenyl ether, amide, and thioether are generated or introduced, so that when used as a filler in ink, it has a significant impact on various properties of the ink. Subsequent testing found that the improvement in the wear resistance and corrosion resistance of the ink is the most obvious, and the water resistance is also improved to a certain extent. DETAILED DESCRIPTION

[0034] In order to better understand the above technical solutions, exemplary embodiments of the present invention are described in more detail below. Although exemplary embodiments of the present invention are shown, it should be understood that the present invention can be implemented in various forms and should not be limited by the embodiments set forth herein. On the contrary, these embodiments are provided to enable a more thorough understanding of the present invention and to fully convey the scope of the present invention to those skilled in the art.

[0035] The particle size of the allophane nanotubes used in the present invention is 100±10nm, the SiO2 content is greater than 28%, the Al2O3 content is greater than 56%, and the density is 1.86-1.88g / cm 3 , purchased from Shandong Qiying Nanotechnology Co., Ltd.

[0036] The present invention will be further described below with reference to the following examples.

[0037] Example 1

[0038] A UV ink for cigarette packaging paper, calculated by weight, comprising:

[0039] 60 parts of polyurethane acrylate, 18 parts of bisphenol A epoxy acrylate, 24 parts of difunctional acrylate, 11 parts of filler modifier, 2.3 parts of pigment, 0.6 parts of dispersant, 0.5 parts of defoamer and 3.9 parts of photoinitiator.

[0040] Among them, the brand of polyurethane acrylate (PUA) is UV-1230; the brand of bisphenol A epoxy acrylate (EA) is Covestro Agisyn1010-A80; and the difunctional acrylate is a mixture of diethylene glycol diacrylate, triethylene glycol diacrylate, and 1,6-hexanediol diacrylate in a mass ratio of 3:4:2.

[0041] Among them, the pigment is organic pigment phthalocyanine red; the dispersant is TEGO-655; the defoaming agent is BYK-085; and the photoinitiator is photoinitiator TPO-L (ethyl 2,4,6-trimethylbenzoylphenylphosphonate).

[0042] The preparation method of the filling modifier includes:

[0043] S1. 1 g of allophane nanotubes was mixed with 25 mL of anhydrous ethanol, and 0.4 g of 3-aminopropyltriethoxysilane was added. The mixture was then refluxed at 60° C. for 7 h. After the treatment, the precipitate was collected by centrifugation in a centrifuge. The precipitate was then rinsed three times with anhydrous ethanol and dried in a vacuum oven to obtain ammoniated allophane nanotubes.

[0044] S2, 0.47g 3-mercaptobenzoic acid was added to 15mL N,N-dimethylformamide, and the mixture was stirred until dissolved. Then, 0.6g condensing agent EDCl (1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride) was added, and the mixture was stirred at room temperature for 1h. Then, 0.36g activator DMAP (4-dimethylaminopyridine) was added, and the mixture was stirred again for 1h. Then, 1g of amination-modified allophane nanotubes was added, and the mixture was stirred and dispersed uniformly. Then, the mixture was stirred at room temperature for 24h. After the reaction was completed, the solvent was removed under reduced pressure, and the solid was collected and rinsed three times with anhydrous ethanol, and then dried in a vacuum oven to obtain modified allophane nanotubes.

[0045] S3. Dissolve 0.38 g of allyl phenyl ether in 40 mL of N,N-dimethylformamide, then add 1 g of modified allophane nanotubes. After uniform dispersion, introduce nitrogen as a protective gas, add 6% of benzoin dimethyl ether by weight of the modified allophane nanotubes, and stir to react under ultraviolet light irradiation at an intensity of 1.8 mw / cm 2 , the wavelength is 365 nm, the reaction time is 1.5 h, and after the reaction is completed, the solvent is removed under reduced pressure, the solid is collected and rinsed three times with anhydrous ethanol, and vacuum dried to obtain a filling modifier.

[0046] The method for preparing the UV ink for cigarette packaging paper comprises the following steps:

[0047] Step 1: firstly mix polyurethane acrylate, bisphenol A epoxy acrylate, and difunctional acrylate, and stir thoroughly to obtain a mixed resin;

[0048] Step 2: adding a filler modifier, a pigment, a dispersant, and a defoamer to the mixed resin, and then grinding the mixture on a three-roll mill and passing it through a 200-mesh sieve to obtain a mixed liquid;

[0049] Step 3: Add a photoinitiator to the mixed liquid, stir thoroughly and evenly to obtain UV ink for cigarette packaging paper.

[0050] Example 2

[0051] A UV ink for cigarette packaging paper, calculated by weight, comprising:

[0052] 50 parts of polyurethane acrylate, 12 parts of bisphenol A epoxy acrylate, 15 parts of difunctional acrylate, 4 parts of filler modifier, 0.9 parts of pigment, 0.4 parts of dispersant, 0.3 parts of defoamer and 2.7 parts of photoinitiator.

[0053] Among them, the brand of polyurethane acrylate (PUA) is UV-1990; the brand of bisphenol A epoxy acrylate (EA) is Covestro Agisyn 1030; and the difunctional acrylate is a mixture of diethylene glycol diacrylate, triethylene glycol diacrylate, and 1,6-hexanediol diacrylate in a mass ratio of 1:2:1.

[0054] The pigment is an organic pigment, including phthalocyanine blue; the dispersant is TEGO-688; the defoaming agent is BYK-1794; and the photoinitiator is photoinitiator 1173 (2-hydroxy-2-methyl-1-phenyl-1-propanone).

[0055] The preparation method of the filling modifier includes:

[0056] S1. 1 g of allophane nanotubes was mixed with 15 mL of anhydrous ethanol, and 0.3 g of 3-aminopropyltriethoxysilane was added, followed by refluxing at 50° C. for 3 h. After the treatment, the precipitate was collected by centrifugation in a centrifuge, and the precipitate was then rinsed three times with anhydrous ethanol and dried in a vacuum oven to obtain ammoniated allophane nanotubes; wherein the mass-to-volume ratio of the allophane nanotubes, 3-aminopropyltriethoxysilane, and anhydrous ethanol was 1 g:0.3 g:15 mL;

[0057] S2, 0.31g 3-mercaptobenzoic acid was added to 10mL N,N-dimethylformamide, and the mixture was stirred until dissolved. Then, 0.4g condensing agent EDCl (1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride) was added, and the mixture was stirred at room temperature for 0.5h. Then, 0.24g activator DMAP (4-dimethylaminopyridine) was added, and the mixture was stirred again for 0.5h. Then, 1g of amination-modified allophane nanotubes was added, and the mixture was first stirred and dispersed uniformly, and then stirred at room temperature for 20h. After the reaction was completed, the solvent was removed under reduced pressure, and the solid was collected and rinsed three times with anhydrous ethanol, and then dried in a vacuum oven to obtain modified allophane nanotubes;

[0058] S3. Dissolve 0.26 g of allyl phenyl ether in 30 mL of N,N-dimethylformamide, then add 1 g of modified allophane nanotubes. After uniform dispersion, introduce nitrogen as a protective gas, add 2% of benzoin diethyl ether by weight of the modified allophane nanotubes, and stir to react under ultraviolet light irradiation at an intensity of 1.2 mw / cm 2 The wavelength is 365 nm, the reaction time is 1-2 h, and after the reaction is completed, the solvent is removed under reduced pressure, the solid is collected and rinsed three times with anhydrous ethanol, and vacuum dried to obtain a filling modifier.

[0059] The method for preparing the UV ink for cigarette packaging paper comprises the following steps:

[0060] Step 1: firstly mix polyurethane acrylate, bisphenol A epoxy acrylate, and difunctional acrylate, and stir thoroughly to obtain a mixed resin;

[0061] Step 2: adding a filler modifier, a pigment, a dispersant, and a defoamer to the mixed resin, and then grinding the mixture on a three-roll mill and passing it through a 100-mesh sieve to obtain a mixed liquid;

[0062] Step 3: Add a photoinitiator to the mixed liquid, stir thoroughly and evenly to obtain UV ink for cigarette packaging paper.

[0063] Example 3

[0064] A UV ink for cigarette packaging paper, calculated by weight, comprising:

[0065] 70 parts of polyurethane acrylate, 24 parts of bisphenol A epoxy acrylate, 30 parts of difunctional acrylate, 18 parts of filler modifier, 5.4 parts of pigment, 0.8 parts of dispersant, 0.7 parts of defoamer and 5.4 parts of photoinitiator.

[0066] Among them, the brand of polyurethane acrylate (PUA) is UV-1205; the brand of bisphenol A epoxy acrylate (EA) is Covestro Agisyn 1050; and the difunctional acrylate is a mixture of diethylene glycol diacrylate, triethylene glycol diacrylate, and 1,6-hexanediol diacrylate in a mass ratio of 5:6:5.

[0067] Among them, the pigment is an organic pigment, including permanent yellow; the dispersant is TEGO-755W; the defoaming agent is BYK-024; and the photoinitiator is photoinitiator 184 (hydroxycyclohexane phenone).

[0068] The preparation method of the filling modifier includes:

[0069] S1. Mixing allophane nanotubes with anhydrous ethanol, adding 3-aminopropyltriethoxysilane, the mass volume ratio of allophane nanotubes, 3-aminopropyltriethoxysilane and anhydrous ethanol is 1g:0.6g:35mL, and then refluxing at 70°C for 10 hours. After the treatment is completed, centrifuging in a centrifuge to collect the precipitate, and then rinsing the precipitate three times with anhydrous ethanol and drying it in a vacuum oven to obtain aminated allophane nanotubes;

[0070] S2, 0.62g of 3-mercaptobenzoic acid was added to 20mL of N,N-dimethylformamide and stirred thoroughly until dissolved. Then, 0.8g of condensing agent EDCl (1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride) was added first, and stirred at room temperature for 1.5h. Then, 0.48g of activator DMAP (4-dimethylaminopyridine) was added, and stirred again for 1.5h. Then, 1g of amination-modified allophane nanotubes was added, and the mixture was first stirred and dispersed uniformly, and then stirred at room temperature for 30h. After the reaction was completed, the solvent was removed under reduced pressure, and the solid was collected and rinsed three times with anhydrous ethanol, and then placed in a vacuum oven to dry to obtain modified allophane nanotubes;

[0071] S3. Dissolve 0.52 g of allyl phenyl ether in 50 mL of N,N-dimethylformamide, then add 1 g of modified allophane nanotubes. After uniform dispersion, introduce nitrogen as a protective gas, add 10% of the weight of the modified allophane nanotubes in benzoin dimethyl ether or benzoin diethyl ether, and stir the mixture under ultraviolet light at an intensity of 2.4 mw / cm 2 , the wavelength is 365 nm, the reaction time is 2 h, and after the reaction is completed, the solvent is removed under reduced pressure, the solid is collected and rinsed three times with anhydrous ethanol, and vacuum dried to obtain a filling modifier.

[0072] The method for preparing the UV ink for cigarette packaging paper comprises the following steps:

[0073] Step 1: firstly mix polyurethane acrylate, bisphenol A epoxy acrylate, and difunctional acrylate, and stir thoroughly to obtain a mixed resin;

[0074] Step 2: adding a filler modifier, a pigment, a dispersant, and a defoamer to the mixed resin, and then grinding the mixture on a three-roll mill and passing it through a 300-mesh sieve to obtain a mixed liquid;

[0075] Step 3: Add a photoinitiator to the mixed liquid, stir thoroughly and evenly to obtain UV ink for cigarette packaging paper.

[0076] Comparative Example 1

[0077] A UV ink for cigarette wrapping paper is disclosed, which differs from Example 1 in that the filler modifier in Example 1 is replaced by ordinary allophane nanotubes, while other components and preparation methods remain unchanged.

[0078] Comparative Example 2

[0079] A UV ink for cigarette packaging paper differs from Example 1 in that the filler modifier in Example 1 is replaced by aminated allophane nanotubes (the same as Example 1), and other components and preparation methods remain unchanged.

[0080] Comparative Example 3

[0081] A UV ink for cigarette packaging paper differs from Example 1 in that the filler modifier in Example 1 is replaced by modified allophane nanotubes (the same as Example 1), and other components and preparation methods remain unchanged.

[0082] Experimental testing

[0083] The UV ink prepared in Example 1 and Comparative Examples 1-3 was applied to the surface of the substrate by flexographic printing, and then placed under a 1000 mW / cm 2 The ink was treated under ultraviolet light at a temperature of 45°C and a treatment time of 6 seconds. The properties of the cured UV ink were tested accordingly. The test items include: adhesion, surface hardness, water resistance and corrosion resistance. The reference standard for adhesion testing is GB / T 9286-1998; the reference standard for surface hardness testing is GB / T 6739-2006; the reference standard for water resistance testing is GB / T 1733-1993; the acid resistance is tested by soaking the ink in a 5wt% hydrochloric acid solution for 24 hours, taking it out and drying it to observe whether the ink is damaged (including fading, shedding or cracking), and the severity level is: large amount > small amount > slight > no abnormality; the alkali resistance is tested by soaking the ink in a 1wt% sodium hydroxide solution for 24 hours, taking it out and drying it to observe whether the ink is damaged (including fading, shedding or cracking), and the severity level is: large amount > small amount > slight > no abnormality; the test results are shown in Table 1:

[0084] Table 1 Ink testing results

[0085]

[0086] As can be seen from Table 1 above, the UV ink of Example 1 has better overall performance, especially in terms of surface hardness, water resistance, and acid and alkali resistance. In addition, it also has excellent adhesion performance. In summary, it can be shown that the UV ink of Example 1 of the present invention is more suitable for application in the field of cigarette packaging paper.

[0087] In the description of this specification, the reference terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" mean that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic expressions of the above terms should not be understood as necessarily referring to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art can combine and combine different embodiments or examples described in this specification.

[0088] Although the embodiments of the present invention have been shown and described above, it will be understood that the above embodiments are illustrative and are not to be construed as limitations on the present invention. A person skilled in the art may change, modify, replace and modify the above embodiments within the scope of the present invention.

Claims

1. A UV ink for cigarette packaging paper, characterized in that: Calculated by weight, including: 50-70 parts of polyurethane acrylate, 12-24 parts of bisphenol A epoxy acrylate, 15-30 parts of difunctional acrylate, 4-18 parts of filler modifier, 0.1-10 parts of pigment, 0.1-1 parts of dispersant, 0.1-1 parts of defoamer and 2.7-5.4 parts of photoinitiator; The bifunctional acrylate is a mixture of diethylene glycol diacrylate, triethylene glycol diacrylate, and 1,6-hexanediol diacrylate, and the mass ratio of diethylene glycol diacrylate, triethylene glycol diacrylate, and 1,6-hexanediol diacrylate is 1-5:2-6:1-5; The preparation method of the filling modifier comprises: S1. Dissolving allophane nanotubes in anhydrous ethanol, adding 3-aminopropyltriethoxysilane, and refluxing at 50-70° C. for 3-10 hours. After the treatment, centrifuging, washing, and drying to obtain ammoniated allophane nanotubes. S2. Add 3-mercaptobenzoic acid to N,N-dimethylformamide and stir thoroughly until dissolved. Then, add the condensing agent EDCl and stir at room temperature for 0.5-1.5 hours. Then, add the activating agent DMAP and stir again for 0.5-1.5 hours. Then, add the amination-modified allophane nanotubes and stir to disperse them uniformly. Then, stir at room temperature for 20-30 hours. After the reaction is completed, remove the solvent under reduced pressure, wash, and dry to obtain modified allophane nanotubes. S3. Dissolve allyl phenyl ether in N,N-dimethylformamide, then add modified allophane nanotubes, and after uniform dispersion, introduce nitrogen as a protective gas, add photoinitiator 2, and stir to react under ultraviolet light for 1-2 hours. After the reaction is completed, remove the solvent under reduced pressure, wash, and dry to obtain a filling modifier; In S1, the mass volume ratio of allophane nanotubes, 3-aminopropyltriethoxysilane and anhydrous ethanol is 1 g: (0.3-0.6) g: (15-35) mL; In S2, the mass volume ratio of aminated allophane nanotubes, 3-mercaptobenzoic acid, condensing agent EDCl, activating agent ‌DMAP and N,N-dimethylformamide is 1 g: (0.31-0.62) g: (0.4-0.8) g: (0.24-0.48) g: (10-20) mL; In S3, the mass volume ratio of modified allophane nanotubes, allyl phenyl ether, and N,N-dimethylformamide is 1 g: (0.26-0.52) g: (30-50) mL; In S3, the irradiation intensity of the ultraviolet light is 1.2-2.4 mw / cm 2 , the wavelength is 280-400nm; the second photoinitiator is benzoin dimethyl ether or benzoin diethyl ether, and the usage amount is 2%-10% of the mass of the modified allophane nanotubes.

2. The UV ink for cigarette packaging paper according to claim 1, characterized in that: The polyurethane acrylate is one of UV-1230, UV-1990, and UV-1205; the bisphenol A epoxy acrylate is one of Covestro Agisyn 1010-A80, Covestro Agisyn 1030, and Covestro Agisyn 1050.

3. The UV ink for cigarette packaging paper according to claim 1, characterized in that: The pigment is an organic pigment, including at least one of phthalocyanine red, phthalocyanine blue, phthalocyanine green, permanent yellow and permanent violet.

4. The UV ink for cigarette packaging paper according to claim 1, characterized in that: The dispersant is at least one of TEGO-655, TEGO-688, TEGO-685, and TEGO-755W; the defoamer is at least one of BYK-085, BYK-1794, BYK-012, and BYK-024; and the photoinitiator is at least one of photoinitiator TPO-L, photoinitiator 1173, and photoinitiator 184.

5. A method for preparing UV ink for cigarette packaging paper according to claim 1, characterized in that: The following steps are involved: Step 1: firstly mix polyurethane acrylate, bisphenol A epoxy acrylate, and difunctional acrylate, and stir thoroughly to obtain a mixed resin; Step 2: adding a filler modifier, a pigment, a dispersant, and a defoamer to the mixed resin, then grinding the mixture on a three-roll mill and passing it through a 100-300 mesh sieve to obtain a mixed liquid; Step 3: Add photoinitiator 1 to the mixed liquid, stir thoroughly to obtain UV ink for cigarette packaging paper.

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