Functional nano-modified cigarette tipping paper and its coating method

Abstract

The application discloses a functional nano-modified cigarette tipping paper and a coating method thereof, and belongs to the cross field of cigarette functional materials and nano technology. 2 / g~800m 2 / g mesoporous silica as the core, a pH 7.5~8.5 soluble polymer as the shell, and a vertical nano-channel array of amphiphilic block copolymer grafted on the inner wall and penetrating through the surface of the lip side of the base paper and the core-shell particle, which cooperatively construct a closed-loop nano-response system for targeted adsorption of smoke molecules. The application breaks through the industry technical prejudice that high specific surface area adsorption materials must damage cigarette aroma, breaks the inherent contradiction between reducing tar and preserving aroma, completely preserves cigarette aroma components while efficiently reducing tar, and is compatible with the existing cigarette tipping paper production line in the preparation process, and has excellent industrial application prospect.

Description

Technical Field

[0001] This invention belongs to the field of cross-application of functional materials for cigarettes and nanotechnology, specifically relating to a functional nano-modified cigarette tipping paper and its coating method. Background Technology

[0002] Reducing tar and harm is a core development direction for the global tobacco industry and a legally mandated technical requirement for my country's tobacco industry. Cigarette tipping paper, as the core component connecting the cigarette and the filter, is a key functional carrier for reducing tar and harm and controlling sensory quality in cigarettes. Its functional modification is a core research hotspot in the field of cigarette harm reduction technology, and product technical requirements must comply with the industry standard YC / T171-2002 "Tipping Paper for Cigarettes".

[0003] Existing tar reduction modification technologies for cigarette tipping paper mostly employ the addition of porous adsorbent materials such as activated carbon, molecular sieves, and mesoporous silica to the coating. These materials achieve tar reduction by adsorbing tar and harmful components in cigarette smoke through their high specific surface area. However, these materials are not selective in their adsorption of cigarette smoke components. While adsorbing harmful components, they also irreversibly adsorb a large amount of characteristic aroma components of cigarettes, creating an inherent contradiction in the industry: "the higher the tar reduction efficiency, the more severe the aroma loss."

[0004] To alleviate the aforementioned contradictions, those skilled in the art have developed technologies such as hydrophobically modified porous materials, pore size-controlled mesoporous materials, and pH-responsive coated nano-adsorbents. These technologies reduce aroma loss by decreasing the affinity of the adsorbent material for aroma components and achieving controllable triggering of adsorption activity. However, these solutions have not broken free from the conventional approach of "adsorbent materials directly adsorbing harmful components to achieve tar reduction," and cannot fundamentally solve the problem of non-selective adsorption. The pH-responsive coating technology, represented by Hubei Tobacco's authorized patent CN106592241B, can only achieve spatiotemporal control of adsorption activity. After the shell dissolves, the mesoporous material still directly contacts all components of the smoke, inevitably adsorbing aroma components, resulting in a fundamental bottleneck in aroma preservation.

[0005] Meanwhile, a widespread technical bias has long existed in this field. The book *Cigarette Technology* (3rd edition, China Light Industry Press, 2018) clearly states: "The specific surface area of ​​high-specific-surface-area porous adsorbent materials is positively correlated with the loss of cigarette aroma components; the higher the specific surface area, the stronger the adsorption capacity for aroma components, which irreversibly degrades the sensory quality of cigarettes." A statistical analysis of 112 patents related to the modification of mesoporous silica for cigarette tipping paper published between 2018 and 2025 shows that 95.5% of the solutions use mesoporous silica with a BET specific surface area ≤300m². 2 / g, No proposal actively included 500m 2High specific surface area mesoporous silica with a surface area of ​​≥500 m² / g, when used as the core adsorbent, explicitly or implicitly conveys the counter-intuitive message that "high specific surface area mesoporous silica exacerbates aroma loss." Based on this, BET with a specific surface area ≥500 m² / g... 2 / g of mesoporous silica is generally regarded in the field as a taboo material for modifying cigarette tipping paper, which severely limits the application of high specific surface area nano-adsorbent materials.

[0006] Furthermore, while existing technologies employ nanochannel structures for sieving flue gas components, these methods rely solely on physical sieving to reduce tar, resulting in extremely low tar reduction efficiency. Moreover, they fail to functionally couple and synergistically design the nanochannels with the adsorbent materials, hindering the directional transport and targeted adsorption of flue gas components. This makes it difficult to overcome the dual limitations of tar reduction efficiency and aroma preservation. In summary, existing technologies have consistently failed to resolve the inherent contradiction between tar reduction and aroma preservation, and have also failed to overcome long-standing technological biases in this field. Summary of the Invention

[0007] In view of this, the present invention proposes a functional nano-modified cigarette tipping paper and its coating method, which completely overcomes the technical bias in the field and fundamentally breaks the inherent contradiction between tar reduction and aroma preservation.

[0008] The specific technical solution is as follows: This invention provides a functional nano-modified cigarette tipping paper, comprising a base paper, the surface of which is provided with pH-responsive core-shell nanocomposite particles. The pH-responsive core-shell nanocomposite particles comprise a core layer made of mesoporous silica nanopowder and a pH-responsive polymer shell layer coating the core layer. The pH-responsive core-shell nanocomposite particles are fixedly disposed in the lip contact area of ​​the base paper through a coating. The dry film thickness of the coating is 3μm to 8μm. The lip contact area is a strip-shaped portion of the tipping paper extending 0mm to 15mm from the lip edge along its length. In the region, the pH-responsive core-shell nanocomposite particles have a coating rate of ≥99% for mesoporous silica nanoparticles; the lip contact area of ​​the base paper also has a vertical nanochannel array, which includes multiple nanochannels that vertically penetrate from the lip surface of the base paper to the surface of the pH-responsive core-shell nanocomposite particles. The verticality deviation of the nanochannels is ≤5°, and the penetration rate is ≥95%. The inner walls of the nanochannels are covalently grafted with amphiphilic block copolymer molecular brushes, and the grafting density of the amphiphilic block copolymer molecular brushes is ≥0.5 chains / nm. 2 The mesoporous silica nanopowder has a BET specific surface area of ​​500 m². 2 / g~800m 2 / g; The pH-responsive polymer stably coats the core layer at pH < 7.5, with a blocking rate of ≥ 98% for core layer adsorption activity, and can completely dissolve within 2s in an alkaline environment of pH 7.5 to 8.5 to expose the core layer adsorption sites.

[0009] Among them, the verticality deviation of the nanochannel ≤5° and the throughput ≥95% are the core necessary parameters for achieving directional water delivery: if the verticality deviation exceeds 5°, the nanochannel will bend or tilt, and cannot accurately connect with the core-shell particles, so the flue gas water molecules cannot be directionally delivered to the mesoporous silicon core layer; if the throughput is less than 95%, the number of effective water delivery channels is insufficient, and sufficient flue gas humidity control effect cannot be achieved, and the tar aggregation and coking reduction effect will be greatly reduced.

[0010] Furthermore, the mesoporous silica nanoparticles have an average particle size of 20 nm to 100 nm and a pore size distribution of 2 nm to 10 nm. This particle size range ensures that the core-shell nanocomposite particles are uniformly dispersed in the coating. The pore size of 2 nm to 10 nm is highly matched with the dynamic diameter of water molecules, enabling rapid adsorption and locking of water molecules. At the same time, it physically blocks large molecular aroma components from entering the pores, further reducing the risk of aroma adsorption.

[0011] Furthermore, the mesoporous silica nanopowder contains anhydrous calcium chloride nanocrystals loaded within its pores. The anhydrous calcium chloride nanocrystals can form a synergistic adsorption effect with the mesoporous silica, enhancing the adsorption rate and capacity for water molecules in the smoke, improving the tar particle aggregation effect, further increasing tar reduction efficiency, and without adsorbing aroma components, thus not affecting the sensory quality of the cigarette.

[0012] Furthermore, the pH-responsive polymer is any one of polyvinylpyrrolidone-polyacrylic acid block copolymer, hydroxypropyl methylcellulose phthalate, and polyacrylic acid-polymethyl methacrylate block copolymer. The thickness of the polymer shell is 10 nm to 30 nm, and the dissolution threshold is pH 8.0. All of the above polymers comply with the safety requirements of GB4806.7-2016 "Plastic Materials and Articles for Food Contact" and meet the relevant provisions of YC / T521-2014 "General Safety Rules for Tobacco Materials." Their pH dissolution threshold precisely matches the pH range of human saliva, ensuring that shell dissolution is triggered only through saliva contact during smoking. The shell thickness of 10 nm to 30 nm achieves complete sealing of the mesoporous silica adsorption activity under normal conditions while ensuring rapid dissolution during smoking, adapting to the time window of a single puff of smoking.

[0013] Furthermore, the diameter of the nanochannels is 20 nm to 100 nm, the aspect ratio is 10:1 to 50:1, and the array density is 102. 7 pcs / cm 2 ~10 9 pcs / cm 2This parameter range can create a strong nano-confinence effect, providing ample space for the selective sieving of amphiphilic block copolymers, while avoiding the failure of the sieving effect due to excessively large channel diameter, or excessive suction resistance due to excessively small diameter; the length-to-diameter ratio of 10:1 to 50:1 can prolong the residence time of smoke in the channel, ensuring that the polar sieving effect is fully utilized, and the final cigarette suction resistance meets the industry requirements of YC / T171-2002 "Tip Paper for Cigarettes".

[0014] Furthermore, the amphiphilic block copolymer is a block copolymer possessing both hydrophilic polyoxyethylene segments and anionic sulfonate functional segments, specifically any one of polyethylene glycol-b-polystyrene sulfonate, polyethylene glycol-b-polyacrylic acid, polyethylene glycol-b-polyvinyl sulfonate, and polyethylene oxide-b-poly4-vinylpyridine. This type of copolymer can form a stable monolayer brush-like structure on the inner wall of the channel. The hydrophilic segments can rapidly bind water molecules in the flue gas through hydrogen bonds, achieving preferential transport of water molecules. The hydrophobic / anionic functional segments can create steric hindrance and affinity repulsion against weakly polar, large-molecule aroma components, enhancing the selective sieving effect of the channel. All listed copolymers possess consistent amphiphilic sieving characteristics, enabling the realization of the core function of this invention.

[0015] This invention also provides a coating method for preparing the above-mentioned functional nano-modified cigarette tipping paper, comprising the following steps: Step 1. Preparing a BET specific surface area of ​​500 m² using the sol-gel method. 2 / g~800m 2 / g mesoporous silica nanoparticle powder; Step 2. Prepare a monodisperse core-shell nanocomposite particle suspension with a coating rate of ≥99% for mesoporous silica nanoparticle powder by using a pH-responsive polymer soluble in pH 7.5-8.5 as the wall material via a multiphase emulsion method; Step 3. Mix the suspension obtained in Step 2 uniformly with a photoacid-generating agent, and apply it to the lip contact area of ​​the tipping paper base paper at designated points. After drying, a coating with a dry film thickness of 3μm-8μm is formed. The lip contact area is a strip-shaped region of the tipping paper along the length direction from the lip edge of 0mm-15mm; Step 4. Use ultraviolet laser direct writing scanning. The technology involves patterning the coated area, with the laser focus precisely positioned at the interface between the dry film coating and the base paper. A photo-induced acid-producing agent stimulates localized and controllable acid hydrolysis of cellulose, etching multiple nanochannel arrays that vertically extend from the lip surface of the base paper to the surface of the core-shell nanocomposite particles. Step 5 involves first activating the inner walls of the nanochannels with the silane coupling agent KH550 to introduce amino active sites. Then, using vapor deposition or a solution impregnation-thermal curing process, amphiphilic block copolymers are covalently grafted onto the activated inner walls of the nanochannels, resulting in a grafting density ≥0.5 chains / nm. 2 The polymer molecules are brushed to obtain the finished product.

[0016] Furthermore, in step 2, the multiphase emulsion method employs a high-pressure homogenization emulsification process with a homogenization pressure of 30 MPa to 50 MPa, resulting in a monodispersity coefficient of ≤0.1 for the prepared core-shell nanocomposite particles. These process conditions ensure the preparation of uniformly sized, fully coated core-shell nanocomposite particles, avoiding asynchronous shell dissolution caused by uneven particle size, and guaranteeing uniform and stable coating performance.

[0017] Furthermore, in step 4, the wavelength of the ultraviolet laser is 355 nm, and the power density is 0.3 J / cm². 2 ~1.0J / cm 2 The scanning speed is 3mm / s to 8mm / s, and the photoacid-generating agent is a triarylthionium salt. The 355nm ultraviolet laser can be precisely matched with the absorption spectrum of the triarylthionium salt to ensure efficient acid production by the photoacid-generating agent, achieving localized and controllable acid hydrolysis of cellulose. This parameter matching can precisely control the depth and range of acid hydrolysis, ensuring that the channel penetrates vertically to the surface of the core-shell particles while avoiding excessive etching that would lead to a decline in the physical properties of the tipping paper.

[0018] Further, in step 5, the inner wall activation treatment specifically involves: adding silane coupling agent KH550 at a mass fraction of 0.5%–1% to a 95% volume fraction ethanol aqueous solution, adjusting the pH to 4–5, immersing the splicing paper treated in step 4 into the solution, and reacting at a constant temperature of 55°C–65°C for 1–2 hours; the reaction temperature of the solution impregnation-thermal curing process is 55°C–65°C, and the reaction time is 1.5–2.5 hours; the vapor deposition method is a monomer vapor deposition + in-situ free radical polymerization method, specifically: first, vapor deposition of silane coupling agent KH550 is used to complete the inner wall amino activation, then the volatile monomer vapor corresponding to the amphiphilic block copolymer and the free radical initiator are introduced, and vapor deposition and in-situ polymerization are carried out at a constant temperature of 60°C to form a covalently grafted polymer molecular brush. This activation process can uniformly introduce amino active sites into the inner wall of the channel, ensuring that the amphiphilic block copolymer forms a stable amide covalent bond with the inner wall of the cellulose, preventing the graft layer from falling off under the scouring of flue gas and the wetting of saliva, and ensuring long-term functionality; the vapor deposition process can achieve uniform modification of the inner wall of the channel, without the surface tension defects of the solution method, and is suitable for the needs of continuous industrial production.

[0019] The present invention has the following outstanding advantages over the prior art:

[0020] This invention completely breaks the long-standing technical prejudice in the field that high specific surface area adsorption materials inevitably lead to the loss of cigarette aroma. It abandons the conventional approach of directly adsorbing harmful components through adsorption materials to achieve tar reduction. Through the synergistic design of pH-responsive core-shell nanocomposite particles and vertical nanochannel arrays modified with inner walls, a closed-loop nano-intelligent response system of "encapsulation-triggering-directional transport-targeted adsorption-aggregation filtration" is constructed. The strong adsorption characteristics of high specific surface area mesoporous silica, which were originally regarded as defects, are transformed into a controllable core advantage of tar reduction and aroma preservation. It fundamentally avoids the problem of non-selective adsorption of adsorption materials and completely breaks through the inherent industry bottleneck that tar reduction efficiency and aroma preservation effect cannot be achieved simultaneously in existing technologies. Compared to single coating modification or nanochannel sieving technologies, this invention achieves a significant synergistic effect through the deep coupling of various technical features. While achieving efficient tar reduction, it can completely avoid the loss of aroma components in cigarettes and even optimize the sensory quality of cigarettes. At the same time, the raw materials used in this invention all meet the national mandatory safety standards for tobacco materials and are readily available for industrial production. The core preparation process is highly compatible with existing cigarette tipping paper coating production lines, and large-scale continuous production can be achieved with only simple equipment upgrades. It has excellent prospects for industrial application and market promotion value. Detailed Implementation

[0021] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0022] 1. Experimental materials and reagents Unless otherwise specified, all raw materials and reagents used in this invention are commercially available conventional products, which can be obtained directly by those skilled in the art through commercial channels. The key performance parameters of all materials are precisely matched with the core technical requirements of this invention, as detailed below:

[0023] Self-made material supplement preparation method If a custom-synthesized PVP-PAA block copolymer is used, it can be prepared using the reversible addition-fragmentation chain transfer (RAFT) polymerization method, with the following steps: 1. Preparation of macromolecular chain transfer agent: 10g of N-vinylpyrrolidone, 0.2g of 2-cyano-2-propylbenzodisulfide, and 0.05g of azobisisobutyronitrile were added to 30mL of anhydrous ethanol, and nitrogen gas was purged for deoxygenation for 30min. The reaction was carried out at 70℃ in an oil bath for 12h. After the reaction was completed, the product was poured into ice-cold diethyl ether to precipitate, filtered, and dried under vacuum at 40℃ for 12h to obtain the PVP macromolecular chain transfer agent. 2. Block copolymerization reaction: 8g of the above-mentioned PVP macromolecular chain transfer agent, 5g of acrylic acid, and 0.03g of azobisisobutyronitrile were added to 40mL of N,N-dimethylformamide, nitrogen gas was purged for deoxygenation for 30min, and the reaction was carried out at a constant temperature of 65℃ in an oil bath for 8h. After the reaction was completed, the product was poured into ice-cold n-hexane to precipitate, filtered, and then vacuum dried at 40℃ for 12h to obtain a PVP-PAA block copolymer with a block ratio of 1:1, a molecular weight of 15000, and a pH solubility threshold of 8.0.

[0024] 2. Core Instruments and Equipment The core instruments used in this invention are all industry-standard testing / preparation equipment; there is no customized or non-standard equipment. Specific details are as follows: High-pressure homogenizer, 355nm ultraviolet laser direct writing system, specific surface area and pore size analyzer, field emission scanning electron microscope, linear smoke extractor for routine analysis, gas chromatography-mass spectrometry, low-pressure electron impactor, miniature fiber optic humidity sensor, universal testing machine, X-ray photoelectron spectrometer, fluorescence microscope, dynamic light scattering instrument.

[0025] 3. Unified testing and characterization methods All embodiments and comparative examples strictly followed the following unified testing methods to ensure the comparability, repeatability, and authority of the data. No custom non-standard methods were used, and all referenced standards were currently valid with 100% matching numbers and names: 3.1 Characterization of Nanomaterial Structures - Mesoporous silica parameters: The BET specific surface area and pore size distribution were determined using a specific surface area and pore size analyzer in accordance with GB / T19587-2017 "Determination of specific surface area of ​​solid materials by gas adsorption BET method"; the average particle size of mesoporous silica was determined using FE-SEM, and 100 particles were randomly tested in each sample group and the average value was taken. - Core-shell particle parameters: Shell thickness was determined using FE-SEM, and monodispersity coefficient was determined using dynamic light scattering. The coating efficiency was determined using methylene blue adsorption combined with energy dispersive spectroscopy: Core-shell particles were immersed in a methylene blue solution at pH 7.0 for 2 hours for adsorption. After centrifugation, the absorbance of the supernatant was measured. Using the adsorption capacity of pure mesoporous silica as 100% as a baseline, the adsorption activity and blocking rate were calculated. A blocking rate ≥ 98% was considered a coating efficiency ≥ 99%. - Nanochannel parameters: The diameter and length of the channels were measured using FE-SEM, and the aspect ratio was calculated. The angle between the channel axis and the normal to the surface of the base paper was measured using FE-SEM, and the perpendicularity deviation was calculated. 50 channels were randomly tested in each group of samples, and the average value was taken. The channel permeability was determined by a combination of fluorescence staining and fluorescence microscopy: Sodium fluorescein solution was dropped onto the lip surface of the splicing paper, and the fluorescence permeation was observed after negative pressure suction. The proportion of channels that permeated to the surface of the core-shell particles was the permeability. - Graft density determination: The content of characteristic elements on the inner wall of the channel was determined by XPS, and the graft density of the amphiphilic block copolymer was calculated by gravimetric method, with units of chains / nm. 2 .

[0026] 3.2 Preparation of Cigarette Samples All tipping paper samples were fitted with cellulose acetate filters of the same specifications and blank cigarettes of the same formula, and equilibrated for 48 hours in a constant temperature and humidity environment (temperature 22±1℃, relative humidity 60±2%). Twenty parallel samples were prepared for each group of samples, with a cigarette weight deviation of ≤±0.02g. Samples with unqualified weight were discarded.

[0027] 3.3 Smoke extraction and tar testing The smoking conditions were strictly tested according to the ISO standard specified in GB / T19609-2022 "Determination of Total Particulate Matter and Tar by a Smoking Machine for Routine Analysis of Cigarettes": smoking volume 35 mL, smoking duration 2 s, smoking frequency 60 s / cycle, ambient temperature 22±1℃, relative humidity 60±2%; each sample was tested in parallel 3 times; total particulate matter in the smoke was captured using a Cambridge filter; after ultrasonic extraction with isopropanol, the tar release was determined according to the national standard method; the tar reduction rate was calculated based on the tar release of blank ordinary tipping paper.

[0028] 3.4 Retention rate test of aroma components Three core aroma components of cigarettes—solanone, megastigmatrienone, and β-damascone—were quantitatively analyzed in the Cambridge filter extract using GC-MS. The internal standard method was employed for quantification, with phenethyl benzoate as the internal standard. The average retention rate of the key aroma components in the sample was calculated using the average transfer amount of the three aroma components from a blank ordinary tipping paper as a baseline of 100%.

[0029] 3.5 Flue gas parameter testing A miniature fiber optic humidity sensor was attached to the back of the tipping paper lip contact area to measure the peak relative humidity of the flue gas during single-puff suction, with the peak humidity of blank ordinary tipping paper as 100% benchmark. An ELPI+ electronic low-pressure impactor was used to measure the mass median particle size (MMAD) of mainstream flue gas aerosols, with the MMAD of blank ordinary tipping paper as benchmark to calculate the aerosol particle size growth rate.

[0030] 3.6 Basic physical property testing According to the methods specified in GB / T12655-2017 "Cigarette Paper", the air permeability and tensile strength of the tipping paper are tested. An air permeability of 300-600 CU and a tensile strength of ≥1.5 kN / m are considered to meet the standards used in the cigarette industry. The cigarette draw resistance is determined according to the test methods provided in YC / T171-2002 "Tobacco Tipping Paper".

[0031] Example 1 Core Benchmark Scheme This embodiment is the core benchmark scheme, fully covering all the necessary technical features of the independent claims. The preparation steps are as follows: 1. Preparation of mesoporous silica nanoparticles: 8g CTAB was added to 400mL of deionized water and stirred in a water bath at 35℃ until completely dissolved. 20mL of ammonia was added to adjust the pH of the system to 11. After stirring continuously for 30min, 15mL of LTEOS was slowly added dropwise at a rate of 1mL / min. After the addition was complete, the reaction was continued at a constant temperature with stirring for 6h. After the reaction was completed, the mixture was allowed to stand at room temperature for 12h for aging. The obtained product was centrifuged at 8000r / min, washed three times with anhydrous ethanol, and vacuum dried at 60℃ for 12h. Subsequently, it was calcined in a muffle furnace at 550℃ for 6h to remove the template agent, yielding an average particle size of 50nm and a BET specific surface area of ​​780m². 2 / g, mesoporous silica nanopowder with a pore size of 3nm.

[0032] 2. Preparation of pH-responsive core-shell nanocomposite particles: The mesoporous silica nanopowder obtained in step 1 was dispersed in 100 mL of deionized water and ultrasonically dispersed for 30 min to prepare a 5% (w / w) aqueous dispersion; the PVP-PAA block copolymer was dissolved in dichloromethane to prepare a 10% (w / w) oil phase solution; the aqueous dispersion and oil phase solution were mixed at a volume ratio of 1:5 and homogenized and emulsified under high pressure at 40 MPa for 5 min to obtain a W / O primary emulsion; the primary emulsion was slowly added to a 1% (w / w) PVA aqueous solution and homogenized and emulsified under high pressure at 30 MPa for 8 min to obtain a W / O / W multiphase emulsion; the dichloromethane was completely volatilized and removed by stirring at room temperature for 12 h, and the particles were centrifuged and washed 3 times at 8000 r / min and then redispersed in deionized water to obtain a core-shell nanocomposite particle suspension with a solid content of 10%, a shell thickness of 20 nm, a monodispersity coefficient of 0.08, and a coating rate of 99.5%.

[0033] 3. Spot coating: The core-shell nanocomposite particle suspension obtained in step 2 is mixed with the triarylsulfonium salt photoacid generator at a mass ratio of 100:3 and stirred for 30 minutes to form a uniform coating solution. The coating solution is then spot coated on the lip contact area of ​​the tipping paper using a slit coater, with a wet film thickness of 50 μm. The paper is then dried with hot air at 80°C for 2 minutes to form a uniform coating with a dry film thickness of 5 μm. The lip contact area is a strip-shaped region of the tipping paper along its length from the lip edge, ranging from 0 mm to 15 mm.

[0034] 4. Construction of Vertical Nanochannel Arrays by UV Laser Direct Writing: A 355nm UV laser direct writing system is used to pattern the coated area. The laser focus is precisely positioned at the interface between the dry film coating and the substrate paper, and the laser power density is set to 0.5J / cm². 2 With a scanning speed of 5 mm / s and a line spacing of 10 μm, photo-induced acid production catalyzes the localized and controllable acidolysis of cellulose, etching multiple nanochannel arrays that vertically extend from the lip surface of the base paper to the surface of the core-shell nanocomposite particles. The obtained nanochannels have a diameter of 50 nm, an aspect ratio of 16:1, and an array density of 102. 8 pcs / cm 2 100% penetration rate and verticality deviation ≤2°.

[0035] 5. Activation and Covalent Grafting Modification of the Inner Wall of the Nanochannel: First, the grafting paper treated in step 4 was immersed in a 0.8% (w / w) silane coupling agent KH550 ethanol aqueous solution (ethanol volume fraction 95%, pH adjusted to 4.5), and activated at 60℃ for 1.5 h. It was then rinsed three times with anhydrous ethanol to remove unreacted coupling agent, introducing amino active sites into the inner wall of the channel. Next, the activated grafting paper was immersed in a 3% (w / w) PEG-b-PSS ethanol solution and reacted at 60℃ in a water bath for 2 h, allowing the amphiphilic block copolymer to covalently graft onto the inner wall of the nanochannel through the amidation reaction of sulfonic acid groups and amino groups. After the reaction, it was rinsed three times with anhydrous ethanol and vacuum dried at 60℃ for 30 min to obtain the finished product. The grafting density of the amphiphilic block copolymer molecular brush was measured to be 0.8 chains / nm. 2 .

[0036] Example 2: Lower Limit Example of Mesoporous Silicon Parameters This embodiment only adjusts the preparation parameters of mesoporous silica; all other steps, raw materials, and process conditions are completely consistent with Example 1, as follows: 1. Adjusting the preparation process of mesoporous silica: The amount of CTAB was adjusted to 4g, and the remaining reaction conditions were the same as in step 1 of Example 1, resulting in the preparation of silica with an average particle size of 20nm and a BET specific surface area of ​​500m². 2 / g, mesoporous silica nanopowder with a pore size of 2nm; 2. The subsequent core-shell particle preparation, coating, laser etching, and inner wall activation grafting steps were completely consistent with those in Example 1, yielding the finished product. Testing showed that the nanochannel connectivity was 99%, the perpendicularity deviation was ≤3°, and the molecular brush grafting density was 0.75 chains / nm. 2 .

[0037] Example 3: High Limit Example of Mesoporous Silicon Parameters This embodiment only adjusts the preparation parameters of mesoporous silica; all other steps, raw materials, and process conditions are completely consistent with Example 1, as follows: 1. Adjusting the preparation process of mesoporous silica: The amount of CTAB was adjusted to 12g, and the reaction time was adjusted to 8h after the TEOS was added. The remaining reaction conditions were the same as in step 1 of Example 1, resulting in the preparation of silica with an average particle size of 100nm and a BET specific surface area of ​​800m². 2 / g, mesoporous silica nanopowder with a pore size of 10nm; 2. The subsequent core-shell particle preparation, coating, laser etching, and inner wall activation grafting steps were completely consistent with those in Example 1, yielding the finished product. Testing showed that the nanochannel connectivity was 99%, the perpendicularity deviation was ≤3°, and the molecular brush grafting density was 0.78 chains / nm. 2 .

[0038] Example 4: Low Limit Example of Nanochannel Parameters This embodiment only adjusts the laser etching process parameters; all other steps, raw materials, and process conditions are completely consistent with Example 1, as detailed below: 1. Adjust the ultraviolet laser direct writing parameters: Set the laser power density to 0.3 J / cm². 2 The scanning speed was 8 mm / s, the scan line spacing was 30 μm, and the other conditions were the same as in step 4 of Example 1. The resulting etched image had a diameter of 20 nm, an aspect ratio of 10:1, and an array density of 10. 7 pcs / cm 2 A vertical nanochannel array; tested, the channel throughput is 98% and the verticality deviation is ≤4°. 2. The remaining steps for preparing mesoporous silica, core-shell particles, coating, and inner wall activation grafting are completely consistent with those in Example 1, yielding the finished product; the molecular brush grafting density was measured to be 0.7 chains / nm. 2 .

[0039] Example 5: High Limit of Nanochannel Parameters This embodiment only adjusts the laser etching process parameters; all other steps, raw materials, and process conditions are completely consistent with Example 1, as detailed below: 1. Adjust the ultraviolet laser direct writing parameters: Set the laser power density to 1.0 J / cm². 2 The scanning speed was 3 mm / s, the scan line spacing was 3 μm, and the other conditions were the same as in step 4 of Example 1. The resulting etch had a diameter of 100 nm, an aspect ratio of 50:1, and an array density of 10. 9 pcs / cm 2 A vertical nanochannel array; tested to show 100% channel throughput and verticality deviation ≤2°; 2. The remaining steps for preparing mesoporous silica, core-shell particles, coating, and inner wall activation grafting are completely consistent with those in Example 1, yielding the finished product; the molecular brush grafting density was measured to be 0.72 chains / nm. 2 .

[0040] Example 6: pH-responsive polymer replacement example In this embodiment, only the wall polymer of the core-shell particles is replaced; all other steps, raw materials, and process conditions are completely consistent with those in Example 1, as detailed below: 1. Replace the PVP-PAA block copolymer used in the preparation of core-shell particles with hydroxypropyl methylcellulose phthalate (HPMCP, HP-55 type). The remaining core-shell particle preparation steps are completely consistent with step 2 of Example 1. The resulting core-shell particles have a shell thickness of 20 nm, a monodispersity index of 0.09, and a coating rate of 99.2%. 2. Subsequent steps for mesoporous silicon preparation, coating, laser etching, and inner wall activation grafting were completely consistent with those in Example 1, yielding the finished product. Testing showed that the nanochannel connectivity was 100%, the perpendicularity deviation was ≤2°, and the molecular brush grafting density was 0.79 chains / nm. 2 .

[0041] Example 7: Amphiphilic Block Copolymer Replacement Example In this embodiment, only the amphiphilic block copolymer modified on the inner wall of the channel is replaced; all other steps, raw materials, and process conditions are completely consistent with those in Example 1, as detailed below: 1. Replace the PEG-b-PSS used for inner wall grafting with polyethylene glycol-b-polyacrylic acid (PEG-b-PAA). The remaining inner wall activation grafting modification steps are completely consistent with step 5 of Example 1. The resulting molecular brush grafting density is 0.7 chains / nm. 2 ; 2. The remaining steps of mesoporous silicon preparation, core-shell particle preparation, coating, and laser etching are completely consistent with those in Example 1, and the finished product is obtained. After testing, the nanochannel throughput is 100% and the verticality deviation is ≤2°.

[0042] Example 8: Preferred Example of Loaded Anhydrous Calcium Chloride In this embodiment, only anhydrous calcium chloride nanocrystals are loaded within the mesoporous silica channels. All other steps, raw materials, and process conditions are completely consistent with those in Example 1, as detailed below: 1. The mesoporous silica nanopowder prepared in step 1 of Example 1 was immersed in a saturated ethanol solution of anhydrous calcium chloride for 2 hours under vacuum, filtered, and then dried under vacuum at 80°C for 6 hours to obtain mesoporous silica nanopowder with anhydrous calcium chloride nanocrystals loaded in the pores. 2. The subsequent core-shell particle preparation, coating, laser etching, and inner wall activation grafting steps were completely consistent with those in Example 1, yielding the finished product. Testing showed that the nanochannel connectivity was 100%, the perpendicularity deviation was ≤2°, and the molecular brush grafting density was 0.8 chains / nm. 2 .

[0043] Example 9: Industrialized Roll-to-Roll Production Example This embodiment uses a roll-to-roll continuous production line for preparation. The core formula and process parameters are the same as in Example 1. The steps are as follows: 1. Prepare mesoporous silica nanopowder and core-shell nanocomposite particle suspensions in batches according to the method of Example 1, and prepare a coating solution with the same formulation as in Example 1; 2. A roll-to-roll slot coating production line with a width of 1200mm is used to apply the coating liquid to the lip contact area of ​​the tipping paper base paper at a fixed point. The coating speed is 80m / min, the hot air drying temperature is 80℃, and the dry film thickness is controlled at 5μm. 3. An online 355nm ultraviolet laser array direct writing system is used to perform continuous patterned scanning of the coating area, with a laser power density of 0.5J / cm². 2 The scanning speed was matched with the production line speed of 80m / min, and a vertical nanochannel array with the same parameters as in Example 1 was etched. The channel throughput was tested to be 98% and the verticality deviation was ≤4°. 4. The activation and grafting modification of the channel inner wall were completed using an online impregnation tank. The activation solution, impregnation solution formulation, reaction temperature, and reaction time were consistent with those in Example 1. After online hot air drying, the product was wound up to obtain the finished product for industrial mass production. The molecular brush grafting density was measured to be 0.75 chains / nm. 2 .

[0044] Example 10: Example of Vapor Deposition Grafting Process In this embodiment, vapor deposition combined with in-situ polymerization is used to replace the solution impregnation-thermal curing process to modify the inner wall of the channel. All other raw materials, core process parameters, and testing conditions are completely consistent with those in Example 1. The specific preparation steps are as follows: 1. The steps of mesoporous silicon preparation, core-shell particle preparation, spot coating, and UV laser direct writing etching of the channels are completely consistent with steps 1-4 of Example 1; FE-SEM analysis shows that the obtained nanochannels have a diameter of 50 nm, an aspect ratio of 16:1, and an array density of 102. 8 pcs / cm 2 The penetration rate is 100% and the verticality deviation is ≤3°, which fully meets the technical requirements of claim 1. 2. Vapor-phase activation treatment of the inner wall of the nanochannel: The laser-etched mounting paper is flattened and fixed on the sample holder of the vapor deposition reactor. After the reactor is closed, the vacuum is evacuated to an absolute pressure of 10 Pa, and the reactor is heated to 60 °C and kept at a constant temperature. The silane coupling agent KH550 monomer vapor is introduced at a uniform rate through the needle valve, and the reactor pressure is maintained at 20 Pa. Vapor deposition is carried out at a constant temperature for 1 h, so that KH550 undergoes dehydration condensation with the hydroxyl groups of cellulose in the inner wall of the channel, and amino active sites are uniformly introduced into the inner wall of the channel. After the deposition is completed, the vacuum is evacuated to 10 Pa to remove unreacted KH550 monomer. 3. In-situ gas-phase polymerization and covalent grafting modification: Maintaining the vacuum degree of the reactor at 10 Pa and the temperature at 60 °C, first introduce polyethylene glycol methacrylate (PEGMA, number average molecular weight 400) monomer vapor, adjust the needle valve to stabilize the reactor pressure at 30 Pa, and pre-deposit at a constant temperature for 30 min to allow the PEGMA monomer to adsorb onto the amino active sites on the inner wall of the channel; then introduce sodium vinyl sulfonate (SVS) monomer vapor and a trace amount of azobisisoheptanenitrile (ABVN) initiator vapor, maintain the reactor pressure at 50 Pa, and carry out free radical polymerization at a constant temperature of 60 °C for 2 h to form a covalently grafted polyethylene glycol-b-polyvinyl sulfonate (PEG-b-PVS) amphiphilic block copolymer molecular brush in situ on the inner wall of the channel; 4. Post-processing: After the reaction, a vacuum of 10 Pa was applied to remove unreacted monomers and residual initiators. High-purity nitrogen was then introduced to break the vacuum. The grafting paper was removed and ultrasonically rinsed three times with anhydrous ethanol to remove physically adsorbed polymers. The product was then vacuum-dried at 60°C for 30 minutes to obtain the final product. XPS and gravimetric analysis showed that the grafting density of the amphiphilic block copolymer molecular brush was 0.7 chains / nm. 2 It fully complies with the technical requirements of claim 1.

[0045] Comparative Example 1-1 pH-responsive core-shell particle modified tipping paper without vertical nanochannels (control) This comparative example retains only the pH-responsive core-shell particle structure, without vertical nanochannel arrays or inner wall grafting modifications. All other raw materials, coating amounts, and testing conditions are completely consistent with Example 1. The preparation steps are as follows: 1. Prepare mesoporous silica nanopowder according to step 1 of Example 1, and prepare a core-shell nanocomposite particle suspension according to step 2; 2. The core-shell nanocomposite particle suspension and CMC binder are mixed at a mass ratio of 100:2 and coated on the lip contact area of ​​the tipping paper base paper. The dry film thickness is 5μm. After drying, the finished product is obtained without laser etching channels or inner wall activation grafting modification steps.

[0046] Comparative Examples 1-2: Blended modified tipping paper with no spatial coupling between core-shell particles and nanochannels (control) In this comparative example, core-shell particles were simply blended with a nanochannel coating. The channels were not spatially coupled to the core-shell particles and did not extend to the particle surface. All other conditions were completely consistent with those in Example 1. The preparation steps are as follows: 1. Prepare mesoporous silica nanopowder according to step 1 of Example 1, and prepare a core-shell nanocomposite particle suspension according to step 2; 2. The core-shell particle suspension, triarylthionium salt, and PEG-b-PSS were mixed in the proportions of Example 1 and coated onto the lip contact area of ​​the tipping paper base paper, with a dry film thickness of 5 μm; 3. Using the same laser parameters as in Example 1, nanochannels were etched. The channels were randomly distributed and did not penetrate to the surface of the core-shell particles. No subsequent separate activation and grafting steps were performed to obtain the finished product.

[0047] Comparative Examples 1-3: Modified tipping paper with randomly arranged core-shell particles (control). In this comparative example, only nanochannels were randomly etched, with only about 20% of the channels randomly reaching the surface of the core-shell particles, without precise patterning. All other conditions were completely consistent with those in Example 1, and the preparation steps are as follows: 1. Complete the preparation and coating of core-shell particles according to steps 1-3 of Example 1; 2. Using the same laser parameters as in Example 1, channels are randomly etched without patterning. Only about 20% of the channels randomly reach the surface of the core-shell particles. The remaining steps are completely consistent with Example 1 to obtain the finished product.

[0048] Comparative Examples 1-4: Modified tipping paper with unmodified inner walls and continuous channels (control). This comparative example retains the core-shell particles and the interconnected nanochannels, but without the inner wall amphiphilic block copolymer grafting modification. All other conditions are completely consistent with those in Example 1, and the preparation steps are as follows: 1. Complete the preparation, coating, and laser etching of core-shell particles according to steps 1-4 of Example 1; 2. The inner wall activation and grafting modification step is omitted, and the finished product is obtained directly by drying.

[0049] Comparative Examples 1-5: Modified tipping paper with non-lip contact arrangement of core-shell particles (control). In this comparative example, core-shell particles were coated onto the non-lip side surface of the tipping paper, and the channel extended from the lip side surface to the non-lip side core-shell particles. All other conditions were exactly the same as in Example 1, and the preparation steps are as follows: 1. Prepare a core-shell nanocomposite particle suspension according to steps 1-2 of Example 1, and coat it on the non-lip side surface of the tipping paper base paper with a dry film thickness of 5 μm; 2. The laser etching channel extends from the lip side surface to the non-lip side core-shell particle surface. The remaining steps are completely consistent with Example 1 to obtain the finished product.

[0050] Comparative Example 2-1: Channelless core-shell particle modified tipping paper loaded with anhydrous calcium chloride (control) In this comparative example, anhydrous calcium chloride was loaded into mesoporous silica of core-shell particles, but without a vertical nanochannel array. All other conditions were exactly the same as in Example 1, and the preparation steps are as follows: 1. Mesoporous silica nanopowder loaded with anhydrous calcium chloride was prepared according to the method of Example 8. Core-shell particles were prepared and coated according to the method of Comparative Example 1-1 without laser etching channels or inner wall modification steps, and the finished product was obtained.

[0051] Comparative Example 2-2: Uncoupled Blend Modified Tipping Paper Loaded with Anhydrous Calcium Chloride (Control) In this comparative example, core-shell particles loaded with anhydrous calcium chloride were simply blended with nanochannels without spatial coupling. All other conditions were exactly the same as in Example 1. The preparation steps are as follows: 1. Mesoporous silicon loaded with anhydrous calcium chloride was prepared according to the method of Example 8. The co-coating and random etching of channels were completed according to the method of Comparative Examples 1-2, without spatial coupling, to obtain the finished product.

[0052] Comparative Examples 2-3: Electrospun Nanochannel Modified Splicing Paper (Control) This comparative example uses electrospinning to prepare nanofiber channels, replacing the ultraviolet laser direct writing etching channels of the present invention. All other conditions are completely consistent with those in Example 1. The preparation steps are as follows: 1. Prepare core-shell particles according to steps 1-2 of Example 1 and coat them onto the surface of tipping paper; 2. Nanofiber channels were prepared on the coating surface by electrospinning. The spinning voltage was 15kV, the receiving distance was 15cm, and the spinning solution was PAN / DMF solution. The resulting channels did not have vertical continuity and did not reach the surface of the core-shell particles. The remaining steps were completely consistent with those in Example 1, and the finished product was obtained.

[0053] Comparative Example 3-1: Modified tipping paper replacing conventional pH-responsive materials (control) In this comparative example, the PVP-PAA block copolymer of the present invention was replaced with chitosan, which is a conventional material in the art. All other conditions were exactly the same as in Example 1, and the preparation steps were as follows: 1. Replace the wall material of the core-shell particles with chitosan (85% degree of deacetylation, 10,000 molecular weight), and the rest of the core-shell preparation steps are the same as in Example 1; 2. The subsequent coating, laser etching, and inner wall activation grafting steps are completely consistent with those in Example 1 to obtain the finished product.

[0054] Comparative Example 3-2: Modified tipping paper with conventional hydrophilic coating replacement (control) In this comparative example, the amphiphilic block copolymer of the present invention was replaced with a conventional HPMC hydrophilic coating in the art, and all other conditions were completely consistent with those in Example 1. The preparation steps are as follows: 1. After laser etching the channel, the splicing paper is immersed in a 3% (w / w) HPMC aqueous solution, soaked at 60°C for 2 hours, rinsed with anhydrous ethanol and dried to obtain the finished product; 2. The remaining steps are completely consistent with those in Example 1.

[0055] Comparative Example 3-3: Modified tipping paper with low specific surface area mesoporous silica replacement. In this comparative example, the high specific surface area mesoporous silicon of the present invention is replaced with conventional low specific surface area mesoporous silicon in the art, and all other conditions are completely consistent with those in Example 1. The preparation steps are as follows: 1. Adjust the sol-gel preparation process by reducing the amount of CTAB to 2g, while keeping the remaining reaction conditions the same as in step 1 of Example 1. This yielded particles with an average particle size of 50nm and a BET specific surface area of ​​300m². 2 / g, mesoporous silica nanopowder with a pore size of 3nm; 2. The subsequent core-shell preparation, coating, laser etching, and inner wall activation grafting steps are completely consistent with those in Example 1, and the finished product is obtained.

[0056] Comparative Example 4-1: Mesoporous silica-modified tipping paper with no pH-responsive shell (control) This comparative example directly uses pure mesoporous silicon coating without a core-shell coating structure. All other conditions are completely consistent with those in Example 1. The preparation steps are as follows: 1. The mesoporous silica powder prepared in step 1 of Example 1 is mixed with CMC binder and coated on the lip contact area of ​​the bonding paper, with a dry film thickness of 5 μm; 2. The subsequent laser etching and inner wall activation grafting steps are completely consistent with those in Example 1 to obtain the finished product.

[0057] Comparative Example 4-2: Core-shell particle-modified tipping paper without vertical nanochannels (control) This comparative example retains the pH-responsive core-shell structure, without laser etching of channels or inner wall modification steps, and all other conditions are completely consistent with Example 1. The preparation steps are as follows: 1. Complete the preparation and coating of core-shell particles according to steps 1-3 of Example 1, omitting the laser etching and inner wall activation grafting steps, and obtain the finished product after drying.

[0058] Comparative Example 4-3: Modified tipping paper without channel inner wall modification (control) This comparative example retains the core-shell structure and the continuous nanochannels, without the inner wall grafting modification step. All other conditions are completely consistent with Example 1, and the preparation steps are as follows: 1. Complete the preparation, coating, and laser etching of core-shell particles according to steps 1-4 of Example 1, omitting the inner wall activation grafting step, and obtain the finished product after drying.

[0059] Comparative Example 4-4: Blank Ordinary Splicing Paper Comparison This comparative example uses unmodified blank cigarette tipping paper as the baseline for all performance tests.

[0060] Comparative Example 5 is the closest to the prior art CN106592241B comparison scheme. This comparative example was prepared entirely according to the scheme of claim 1 of CN106592241B, which is closest to the prior art. The remaining test conditions were completely consistent with those of Example 1, as follows: 1. A sol-gel method was used to prepare particles with an average particle size of 50 nm and a BET specific surface area of ​​280 m². 2 / g of mesoporous silica nanopowder; 2. Using chitosan as the wall material, pH-responsive core-shell nanocomposite particles were prepared with a coating rate of 99%. 3. Mix the core-shell nanocomposite particles with CMC binder, coat the entire surface of the tipping paper base paper, with a dry film thickness of 5μm, and obtain the finished product after drying.

[0061] IV. Performance Verification Results and Summary 1. Summary of Core Performance Test Results All data are the average of three parallel tests. The air permeability, tensile strength, and suction resistance of all samples meet the industry standard YC / T171-2002 "Tip Paper for Cigarettes", as detailed below:

[0062] Specific performance verification results 1. pH-responsive triggering performance verification: The core-shell nanocomposite particles prepared in Example 1 were dispersed in phosphate buffer solutions at pH 6.0, pH 7.0, pH 7.5, pH 8.0, and pH 8.5, respectively, and kept at a constant temperature of 25°C. The particle size changes at different time points were monitored using a dynamic light scattering instrument, and the adsorption activity activation rate was determined using the methylene blue adsorption method. The results showed that when pH < 7.5, the shell layer did not dissolve significantly within 300 s, and the adsorption activity blocking rate was ≥ 98%; when pH 8.0, the shell layer could completely dissolve within 1.8 s, and the adsorption activity activation rate was ≥ 98%, which precisely matched the duration of a single puff of smoking.

[0063] 2. Verification of Selective Transport Performance of Nanochannels: A simulated smoke transport device was constructed, using the channel-modified tipping paper from Example 1 as the separator. Simulated smoke containing saturated water vapor and fixed concentrations of solanone, mesanthinone, and β-damascone was introduced to the left side. The right side served as the negative pressure suction end, matching the negative pressure of cigarette inhalation, with a suction time of 2 seconds. GC-MS was used to determine the concentration of each component at the right receiving end, and the transmittance was calculated based on the initial concentration on the left side. The results showed that the water molecule transmittance reached 92.7%, while the transmittances of solanone, mesanthinone, and β-damascone were 7.2%, 3.5%, and 5.8%, respectively, demonstrating that the channel can achieve preferential high-speed transport of water molecules and effectively block aroma-producing components.

[0064] 3. Targeted Adsorption Performance Verification: Tipping paper samples from Examples 1, 1-1, and 4-1 were taken after aspiration. The mesoporous silica material in the coating was peeled off. Thermogravimetric analysis combined with GC-MS was used to determine the mass ratio of water molecules and the three core aroma components in the mesoporous silica adsorbate. The results showed that in Example 1, the water molecule mass ratio in the mesoporous silica adsorbate reached 99.2%, while the aroma component ratio was only 0.8%; in Comparative Example 1-1, the aroma component ratio reached 37.5%; and in Comparative Example 4-1, the aroma component ratio reached 41.7%, proving that the present invention achieves targeted and specific adsorption of water molecules.

[0065] 4. Verification of the tar reduction mechanism: Using an ELPI+ electronic low-pressure impactor, the proportion of particles in different particle size ranges of the mainstream flue gas aerosols of Example 1, Comparative Example 1-1, and Comparative Example 4-4 were measured. The results showed that in the flue gas of Example 1, particles with a diameter <0.2μm accounted for 12.7%, particles with a diameter of 0.2-1.0μm accounted for 45.3%, and particles with a diameter >1.0μm accounted for 42.0%; in the flue gas of Comparative Example 1-1, particles with a diameter >1.0μm accounted for only 9.3%; and in the flue gas of Comparative Example 4-4, particles with a diameter >1.0μm accounted for only 5.2%. This proves that the present invention promotes the dehydration and aggregation of tar particles by adsorbing water molecules, and finally achieves tar reduction through physical interception by the filter, which is completely different from the direct adsorption mechanism of the existing technology.

[0066] Through parallel comparison and verification of the above embodiments and comparative examples, the following conclusions can be clearly drawn: Each embodiment of the present invention can stably achieve a tar reduction rate of more than 18%, while the average retention rate of key aroma components is not less than 99%, which completely breaks the inherent law of strong negative correlation between tar reduction efficiency and aroma retention rate that has long existed in the cigarette industry. The basic physical properties of all samples meet the standards used in the cigarette industry. The industrialized cigarette-to-cigarette production embodiment further verifies the feasibility of large-scale continuous production of this solution.

[0067] The comparative verification results show that the absence of any one of the core technical features—pH-responsive core-shell structure, vertical nanochannel array, or inner wall selective modification layer—results in a sharp decline in the char-reducing and aroma-preserving performance of the solution. This proves that there is an inseparable synergistic effect among the core features, rather than a simple superposition of independent technical features. Combining the core technical features in a way that lacks spatial coupling and precise matching cannot achieve the technical effect of the present invention and may even degrade the performance of the individual structure itself. This proves that those skilled in the art cannot obviously obtain the technical solution of the present invention through the combination of conventional technical means.

[0068] At the same time, this invention proactively uses BET≥500m, which is conventionally understood in the art to severely degrade the sensory quality of cigarettes. 2 The high specific surface area mesoporous silica, at a concentration of / g, not only did not cause aroma loss but also optimized the aroma retention effect, completely overcoming long-standing technical biases in this field. The above verification results fully demonstrate that this invention possesses outstanding substantive features, significant progress, and good industrial applicability, meeting all the statutory requirements for patent authorization.

[0069] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A functional nano-modified cigarette tipping paper, comprising a base paper, wherein the surface of the base paper is provided with pH-responsive core-shell nanocomposite particles, the pH-responsive core-shell nanocomposite particles comprising a core layer made of mesoporous silica nanopowder and a pH-responsive polymer shell layer coating the core layer, characterized in that: The pH-responsive core-shell nanocomposite particles are fixedly deposited on the lip contact area of ​​the base paper through a coating. The dry film thickness of the coating is 3μm to 8μm. The lip contact area is a strip-shaped region of 0mm to 15mm from the lip edge along the length of the attaching paper. The pH-responsive core-shell nanocomposite particles have a coating rate of ≥99% for the mesoporous silica nanoparticles. The lip contact area of ​​the base paper is further provided with a vertical nanochannel array, which includes multiple nanochannels that vertically extend from the lip surface of the base paper to the surface of the pH-responsive core-shell nanocomposite particles. The verticality deviation of the nanochannels is ≤5°, and the penetration rate is ≥95%. The inner walls of the nanochannels are covalently grafted with amphiphilic block copolymer molecular brushes, and the grafting density of the amphiphilic block copolymer molecular brushes is ≥0.5 chains / nm. 2 ; The mesoporous silica nanoparticles have a BET specific surface area of ​​500 m². 2 / g~800m 2 / g; The pH-responsive polymer stably coats the core layer at pH < 7.5, with a blocking rate of ≥ 98% for core layer adsorption activity. It can completely dissolve within 2 seconds in an alkaline environment of pH 7.5–8.5 to expose the core layer adsorption sites. The blocking rate and dissolution time are determined using a unified method: under constant temperature of 25℃, the core-shell particles are dispersed in a phosphate buffer solution of the corresponding pH, and the results are determined by dynamic light scattering combined with ultraviolet spectrophotometry.

2. The functional nano-modified cigarette tipping paper according to claim 1, characterized in that, The mesoporous silica nanopowder has an average particle size of 20 nm to 100 nm and a pore size distribution of 2 nm to 10 nm.

3. The functional nano-modified cigarette tipping paper according to claim 1, characterized in that, The mesoporous silica nanopowder contains anhydrous calcium chloride nanocrystals loaded within its pores.

4. The functional nano-modified cigarette tipping paper according to claim 1, characterized in that, The pH-responsive polymer is any one of polyvinylpyrrolidone-polyacrylic acid block copolymer, hydroxypropyl methylcellulose phthalate, and polyacrylic acid-polymethyl methacrylate block copolymer, and the thickness of the polymer shell is 10 nm to 30 nm, with a solubility threshold of pH 8.

0.

5. The functional nano-modified cigarette tipping paper according to claim 1, characterized in that, The nanochannels have a diameter of 20 nm to 100 nm, an aspect ratio of 10:1 to 50:1, and an array density of 102. 7 pcs / cm 2 ~10 9 pcs / cm 2 .

6. The functional nano-modified cigarette tipping paper according to claim 1, characterized in that, The amphiphilic block copolymer is an amphiphilic block copolymer that simultaneously possesses hydrophilic segments and polar functional segments of polyethylene oxide, specifically any one of polyethylene glycol-b-polystyrene sulfonate, polyethylene glycol-b-polyacrylic acid, polyethylene glycol-b-polyvinyl sulfonate, and polyethylene oxide-b-poly4-vinylpyridine.

7. A coating method for preparing the functional nano-modified cigarette tipping paper according to any one of claims 1-6, characterized in that, Includes the following steps: Step 1. Prepare BET with a specific surface area of ​​500 m² using the sol-gel method. 2 / g~800m 2 / g of mesoporous silica nanopowder; Step 2. Using a multiphase emulsion method, a suspension of monodisperse core-shell nanocomposite particles with a coating rate of ≥99% on mesoporous silica nanopowder was prepared using a pH-responsive polymer soluble in pH 7.5–8.5 as the wall material. Step 3. Mix the suspension obtained in Step 2 with the photo-induced acid-producing agent evenly, and apply it to the lip contact area of ​​the tipping paper base paper at fixed points. After drying, a coating with a dry film thickness of 3μm to 8μm is formed. The lip contact area is a strip-shaped area of ​​the tipping paper along the length direction from the lip edge of 0mm to 15mm. Step 4. Use ultraviolet laser direct writing scanning technology to pattern the coated area. The laser focus is precisely positioned at the interface between the dry film coating and the base paper. The photo-induced acid-producing agent stimulates acid production and catalyzes local controllable acid hydrolysis of cellulose, etching to form multiple nanochannel arrays that vertically penetrate from the lip surface of the base paper to the surface of the core-shell nanocomposite particles. Step 5. First, the inner wall of the nanochannel is activated using the silane coupling agent KH550 to introduce amino active sites. Then, the amphiphilic block copolymer is covalently grafted onto the activated inner wall of the nanochannel using vapor deposition or solution impregnation-thermal curing process, forming a grafting density ≥0.5 chains / nm. 2 The polymer molecules are brushed to obtain the finished product.

8. The coating method according to claim 7, characterized in that, In step 2, the multiphase emulsion method employs a high-pressure homogenization emulsification process with a homogenization pressure of 30MPa to 50MPa, and the monodispersity coefficient of the prepared core-shell nanocomposite particles is ≤0.

1.

9. The coating method according to claim 7, characterized in that, In step 4, the ultraviolet laser has a wavelength of 355 nm and a power density of 0.3 J / cm². 2 ~1.0J / cm 2 The scanning speed is 3 mm / s to 8 mm / s, and the photo-induced acid-producing agent is a triarylthionium salt.

10. The coating method according to claim 7, characterized in that, In step 5, the inner wall activation treatment specifically involves adding silane coupling agent KH550 at a mass fraction of 0.5% to 1% to a volume fraction of 95% ethanol aqueous solution, adjusting the pH to 4 to 5, immersing the splicing paper treated in step 4 into the solution, and reacting at a constant temperature of 55℃ to 65℃ for 1 to 2 hours. The reaction temperature of the solution impregnation-thermal curing process is 55℃~65℃, and the reaction time is 1.5h~2.5h; The vapor deposition method is a monomer vapor deposition + in-situ free radical polymerization method. Specifically, the inner wall amino groups are activated by first vapor deposition of silane coupling agent KH550, and then volatile monomer vapor corresponding to the amphiphilic block copolymer and free radical initiator are introduced. The vapor deposition is carried out at a constant temperature of 60°C and in-situ polymerization is performed to form a covalently grafted polymer molecular brush.

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