A flavor enhancing unit and a cigarette filter rod

Abstract

The present application relates to the field of cigarette filter technology, and discloses a flavoring unit and a cigarette filter rod. The flavoring unit is a cylinder with longitudinal multi-channels formed by embossing, folding or gathering of a composite sheet, the composite sheet comprises a fiber framework layer, flavoring gel filled in the fiber framework layer, and a non-woven fabric surface layer coated outside the fiber framework layer, and the fiber framework layer comprises two or more fiber webs overlapped together. The flavoring unit and the cigarette filter rod can load the flavoring gel by the fiber framework layer, and then coat the non-woven fabric surface layer, so as to limit the flavoring gel inside, and even if phase transition occurs during smoking, the flavoring gel will not expand or flow downward and gather to affect the problem of suction resistance.

Description

Technical Field

[0001] This invention relates to the field of cigarette filter technology, and more particularly to an aroma-enhancing unit and a cigarette filter rod. Background Technology

[0002] Flavored filter rods have attracted much attention because they prevent the loss and pyrolysis of flavorings and fragrances during cigarette storage and smoking; prevent the loss of flavorings and fragrances during cigarette static burning; reduce the retention of flavorings and fragrances by tobacco and filter, and increase transfer efficiency; and can simultaneously achieve diversified flavor enhancement and personalized appearance.

[0003] Most existing cigarette filter rods are made primarily from tobacco tow, plant fibers, and filter rod forming paper, processed through rolling and slitting to create round rods that filter cigarette smoke. Flavoring methods for filter rods include flavoring with threads, flavoring with capsules, flavoring with gels, and flavoring with granules. Flavoring with threads, however, suffers from limited absorption of flavoring substances due to the relatively small amount of cotton thread used, resulting in a short-lasting aroma and limited ability to absorb harmful substances, potentially affecting the sensory quality of the cigarette. As for flavoring with capsules and granules, their placement is prone to shifting, and they often only provide flavor to specific areas within the filter rod, leading to uneven smoke flavor and a tendency for the aroma to fade over time.

[0004] Gel flavoring utilizes a gel material to load flavorings and fragrances. During inhalation, the high-temperature smoke passes through the gel, causing a phase change and releasing the stored flavorings and fragrances. This method offers better control, a larger flavoring load, and easier transportation and storage. However, in existing technologies, gel flavoring is often applied directly to the filter rod. During inhalation, the phase change can cause the gel to flow downwards and aggregate, blocking the smoke passages between the cigarette filter fibers. This significantly increases draw resistance, reduces smoke flow, and negatively impacts the smoking experience. Summary of the Invention

[0005] In view of this, the purpose of the present invention is to provide a flavoring unit and a cigarette filter rod, which loads the flavoring gel through a fiber skeleton layer and then covers it with a non-woven fabric surface layer, which can limit the internal flavoring gel and prevent it from expanding or flowing downward and agglomerating, thus affecting the draw resistance, even if a phase change occurs during inhalation.

[0006] The present invention solves the above-mentioned technical problems through the following technical means:

[0007] A fragrance-enhancing unit, wherein the fragrance-enhancing unit is a cylinder with longitudinal multi-channels formed by embossing, folding or gathering a composite sheet, the composite sheet comprising a fiber skeleton layer, a fragrance-enhancing gel filled in the fiber skeleton layer, and a non-woven fabric surface layer covering the fiber skeleton layer, the fiber skeleton layer comprising two or more fiber webs overlapping each other.

[0008] Furthermore, the fiber web is woven from modified polylactic acid nanofibers.

[0009] Furthermore, the modified polylactic acid nanofiber is made by electrospinning polylactic acid, polycaprolactone, porous nano silica, and gallic acid as the main raw materials.

[0010] Furthermore, the nonwoven fabric surface layer is made of biodegradable material using hydroentangling, needle punching, or hot rolling processes, with a corresponding basis weight of 25-40 g / m². 2 .

[0011] Furthermore, the biodegradable material is made from one or more of polylactic acid, chitosan, polyester, cellulose acetate, gelatin, and chitosan.

[0012] Furthermore, the modified polylactic acid nanofibers are aggregated to form modified polylactic acid nanofiber bundles with a diameter of 0.1-0.15 mm. The polycaprolactone nanofiber bundles are then woven into a web using a weaving machine. The web is then microwaved in a microwave oven for 15-20 minutes, removed, and subjected to low-temperature plasma treatment. After being sprayed with chitosan solution, the web is dried under infrared light heating to obtain the fiber web.

[0013] The modified polylactic acid (PLA) nanofibers were woven into a web and then microwaved. The modified PLA nanofibers absorbed the energy from the microwaves, making the PLA nanofiber bundles fluffy and increasing their specific surface area. Then, they were treated with low-temperature plasma to introduce active groups on the surface of the modified PLA nanofibers, increasing their wettability. Chitosan solution was sprayed and heated under infrared light, causing chitosan to precipitate and be loaded onto the modified PLA nanofiber bundles, increasing their adhesion properties and facilitating the subsequent loading of fragrance gels.

[0014] Furthermore, the preparation method of the modified polylactic acid nanofibers is as follows: After the dried polycaprolactone particles and polylactic acid particles are mixed evenly, they are placed in a micro-mixing rheometer and melt-processed for 5-10 minutes at a speed of 65 rpm and a temperature of 150-170℃. The resulting mixture is added to 1,4-dioxane, heated to 70-80℃, and stirred until no visible particles are present. Gallic acid and acetic anhydride are added, and the mixture is heated to 110-120℃ under a nitrogen atmosphere and stirred for 2-3 hours. After the reaction is completed, the mixture is cooled to room temperature, filtered, and the solid is freeze-dried and then dissolved in hexafluoroisopropanol. Porous nano-silica is added to obtain a spinning solution with a mass fraction of 8%. The spinning solution is transferred to a syringe and electrospinned to obtain modified polylactic acid nanofibers.

[0015] Furthermore, the method for preparing the composite sheet is as follows:

[0016] Preparation of fiber skeleton layer: The prepared fiber web is stacked in multiple layers, and the edges are bonded together by hot pressing. Then it is soaked in deionized water, and bis(octadecyl)dimethylammonium chloride is added. After stirring for 10-20 min, sodium pyrophosphate is added, and the mixture is ultrasonically treated under intermittent pulsed ultrasound for 4-6 h. The fiber skeleton layer is then removed, washed in deionized water until neutral, and then air-dried to obtain the fiber skeleton layer.

[0017] Filling: Heat the prepared fiber skeleton layer to 30-35℃, cover it with a non-woven fabric surface layer, cover the outermost non-woven fabric surface layer, heat it to 60-70℃, keep it at that temperature for 5 minutes, then fill the fiber skeleton layer with fragrance gel, and obtain a composite sheet after cooling.

[0018] The multi-layer fiber web was treated with bis(octadecyldimethylammonium chloride) and sodium pyrophosphate, which increased the softness of the fiber web and also increased the spacing between adjacent fiber web layers to a certain extent, thereby increasing the bulkiness of the fiber skeleton layer and enabling it to carry more flavoring gel.

[0019] In addition, this application also discloses a cigarette filter rod, including the aforementioned flavoring unit.

[0020] The beneficial effects of this invention are:

[0021] 1. The flavoring unit of this invention, obtained by embossing, folding, and gathering a composite sheet, has multiple longitudinal channels. During inhalation, smoke flows through the channels, and the flavoring gel is heated to release fragrance, achieving a flavoring effect without affecting the overall draw resistance of the filter rod. The composite sheet of this invention has a fiber skeleton layer that supports both the internal flavoring gel and the external non-woven fabric layer, preventing the external non-woven fabric layer from bulging outward after the internal flavoring gel undergoes a phase change. It also ensures the hardness of the entire flavoring unit, ensuring that the hardness of the filter rod made from it meets relevant requirements. On the other hand, the fiber skeleton layer also acts as a carrier for the internal flavoring gel, further limiting its position and preventing it from flowing downward after a phase change during use, thus preventing aggregation.

[0022] 2. The fiber web of the present invention is formed by weaving modified polylactic acid nanofibers. Polylactic acid and polycaprolactone themselves have good biodegradability. By adding gallic acid, the adhesion performance of the modified polylactic acid nanofibers can be increased, enabling them to better combine with the nonwoven fabric surface layer and the flavoring gel. At the same time, porous nano-silica is also added during the preparation of the fiber web. On the one hand, the addition of porous nano-silica can increase the mechanical properties of the nanofibers and increase their hardness. On the other hand, porous nano-silica also has good thermal conductivity and adsorption properties, which can transfer the heat in the flue gas to the internal flavoring gel in a timely manner. At the same time, it can also adsorb some harmful substances in the flue gas, thereby achieving the purpose of flavor enhancement and harm reduction. Detailed Implementation

[0023] 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 some embodiments of the present invention, and not all 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.

[0024] This invention discloses a fragrance-enhancing unit comprising a cylindrical structure with longitudinally multi-channels formed by embossing, folding, or gathering a composite sheet. The composite sheet includes a fiber skeleton layer, a fragrance-enhancing gel filling the fiber skeleton layer, and a non-woven fabric surface layer covering the fiber skeleton layer. The fiber skeleton layer comprises two or more overlapping fiber webs, wherein the fiber webs are made of modified polylactic acid nanofibers woven from modified polylactic acid nanofibers. The modified polylactic acid nanofibers are made from polylactic acid, polycaprolactone, porous nano-silica, and gallic acid as main raw materials through electrospinning. The non-woven fabric surface layer is made of biodegradable materials using hydroentangling, needle punching, or hot rolling processes, with a corresponding basis weight of 25-40 g / m². 2The specific preparation method is as follows:

[0025] Example 1

[0026] Preparation of modified polylactic acid nanofibers:

[0027] After the dried polycaprolactone granules and polylactic acid granules were mixed evenly at a mass ratio of 5:1, they were placed in a micro-mixing rheometer and melt-processed for 10 minutes at a speed of 65 rpm and a temperature of 150°C to obtain the mixture. 40 In a mixture of polycaprolactone (PP) and 1,4-dioxane, the temperature was raised to 80°C and stirred until no visible particles were observed. Gallic acid and acetic anhydride were added in a mass ratio of 10:1:0.1. Under a nitrogen atmosphere, the temperature was raised to 120°C and stirred for 3 hours. After the reaction was complete, the mixture was cooled to room temperature, filtered, and the resulting solid was freeze-dried and dissolved in hexafluoroisopropanol. 0.12 times the mass of PP-containing porous nano-silica was added, and the mixture was ultrasonically dispersed to obtain a spinning solution with a PP content of 6%. The spinning solution was transferred to a syringe, and electrospinning was performed under conditions of a feed rate of 0.5 ml / h, a spinning electrostatic voltage of 20 kV, and a receiving distance of 15 cm to obtain modified polylactic acid nanofibers.

[0028] Preparation of fiber web:

[0029] Modified polylactic acid (PLA) nanofibers were aggregated to form PLA nanofiber bundles with a diameter of 0.1-0.12 mm. The polycaprolactone (PVC) nanofiber bundles were then woven into a mesh using a braiding machine. The mesh was then microwaved at 650 W for 18 minutes. Afterward, it was placed in a low-temperature plasma device with air as the working gas and subjected to low-temperature plasma treatment at a discharge power of 150 W for 5 minutes. The plasma was then discharged at a rate of 5 ml / cm². 2 A 1 wt% chitosan solution was sprayed onto the fiber and then dried under infrared light heating to obtain a fiber web.

[0030] Preparation of composite sheets

[0031] In this embodiment, the composite sheet uses a nonwoven fabric obtained by spunbonding and hot-rolling acetate material as the nonwoven fabric surface layer, with a corresponding basis weight of 25 g / m². 2 .

[0032] Preparation of the fiber skeleton layer: The three layers of the prepared fiber web are overlapped together, leaving one side open. The remaining edges are bonded together by hot pressing. Then, the fiber web is immersed in deionized water, with the amount of deionized water just enough to completely submerge it. Dioctadecyl dimethyl ammonium chloride is added, and after stirring for 20 minutes, sodium pyrophosphate is added. The mass ratio of deionized water, dioctadecyl dimethyl ammonium chloride, and sodium pyrophosphate is 10:0.5:2. The fiber skeleton layer is then ultrasonically treated for 5 hours at a frequency of 25 kHz and a power of 100 W using intermittent pulsed ultrasound. After treatment, the fiber skeleton layer is removed, washed with deionized water until neutral, and then air-dried to obtain the fiber skeleton layer. In this embodiment, the pulse working time of the intermittent pulsed ultrasound is 3 seconds, and the pulse interval is 5 seconds.

[0033] Filling: The prepared fiber skeleton layer is heated to 32°C, covered with a non-woven fabric surface layer, and then covered with a non-woven fabric surface layer on the outermost side. The temperature is raised to 60°C and kept for 5 minutes. Then, the fragrance gel is filled into the fiber skeleton layer. After cooling, a composite sheet is obtained.

[0034] The prepared composite sheet is embossed, folded, and gathered to form a continuous cylindrical strip with multiple longitudinal channels and uniformity. It is then cut into a cylinder with a porous surface and a length of 144 mm. Further cutting into segments with a length of 20 mm yields the flavoring unit.

[0035] The prepared flavoring unit was combined with a regular acetate fiber filter rod to obtain a binary cigarette filter rod. This binary cigarette filter rod was used to prepare cigarette samples for draw resistance testing under inhalation conditions. Simultaneously, using existing methods, flavoring gel was directly added to the cigarette filter tow to form a flavoring segment. This flavoring segment was then combined with a regular acetate fiber filter rod to obtain a binary cigarette filter rod, which was used to prepare cigarettes as a control. The test results are shown in Table 1.

[0036] Table 1 Test Results

[0037] Sample Name Initial pull-in resistance (Pa) Suction resistance (Pa) when half of the suction is complete. Suction resistance (Pa) after suction is complete control sample 4329 4527 4812 Cigarette samples 3841 3854 3876

[0038] As can be seen from the data in Table 1, the aroma-enhancing unit of the present invention can significantly reduce the draw resistance of the prepared cigarette filter rod. At the same time, it does not affect the smoke channel in the cigarette filter rod during the smoking process, and the draw resistance of the prepared cigarette filter rod changes little.

[0039] Example 2

[0040] Preparation of modified polylactic acid nanofibers:

[0041] After the dried polycaprolactone granules and polylactic acid granules were mixed evenly at a mass ratio of 7:3, they were placed in a micro-mixing rheometer and melt-processed for 10 minutes at a speed of 65 rpm and a temperature of 170°C to obtain the mixture. 45% of the mixture was then added to the solution. In a mixture of polycaprolactone and 1,4-dioxane, the temperature was raised to 70°C and stirred until no visible particles were found. Gallic acid and acetic anhydride were added, with a mass ratio of polycaprolactone, gallic acid, and acetic anhydride of 10:1:0.1. Under a nitrogen atmosphere, the temperature was raised to 115°C and stirred for 3 hours. After the reaction was completed, the mixture was cooled to room temperature, filtered, and the resulting solid was freeze-dried and then dissolved in hexafluoroisopropanol. Porous nano-silica with a mass of 0.12 times that of polycaprolactone was added, and the mixture was ultrasonically dispersed to obtain a spinning solution with a polycaprolactone mass fraction of 7%. The spinning solution was transferred to a syringe, and electrospinning was performed under the conditions of a feed rate of 0.8 ml / h, a spinning static voltage of 20 kV, and a receiving distance of 15 cm to obtain modified polylactic acid nanofibers.

[0042] Preparation of fiber web:

[0043] Modified polylactic acid (PLA) nanofibers were aggregated to form PLA nanofiber bundles with a diameter of 0.13-0.15 mm. The polycaprolactone (PVC) nanofiber bundles were then woven into a mesh using a braiding machine. The mesh was then microwaved at 650 W for 15 minutes. Afterward, it was placed in a low-temperature plasma device with air as the working gas and subjected to low-temperature plasma treatment at a discharge power of 150 W for 5 minutes. The plasma was then discharged at a rate of 3 ml / cm². 2 A 1 wt% chitosan solution was sprayed onto the fiber and then dried under infrared light heating to obtain a fiber web.

[0044] Preparation of composite sheets

[0045] In this embodiment, the composite sheet uses polylactic acid material spunbonded and hot-rolled to obtain a nonwoven fabric as the nonwoven surface layer, with a corresponding basis weight of 30 g / m². 2 .

[0046] Preparation of the fiber skeleton layer: The two layers of the prepared fiber mesh are overlapped together, leaving one side open. The remaining edges are bonded together by hot pressing. Then, the fiber mesh is soaked in deionized water, and the amount of deionized water is just enough to completely submerge the fiber mesh. Dioctadecyl dimethyl ammonium chloride is added, and after stirring for 20 minutes, sodium pyrophosphate is added. The mass ratio of deionized water, dioctadecyl dimethyl ammonium chloride, and sodium pyrophosphate is 10:0.4:2.5. The fiber skeleton layer is ultrasonically treated for 6 hours under intermittent pulsed ultrasound at a frequency of 25 kHz and a power of 100 W. The fiber skeleton layer is then removed and air-dried naturally. In this embodiment, the pulse working time of the intermittent pulsed ultrasound is 3 seconds, and the pulse interval is 5 seconds.

[0047] Filling: The prepared fiber skeleton layer is heated to 35°C, covered with a non-woven fabric surface layer, and then covered with a non-woven fabric surface layer on the outermost side. The temperature is raised to 65°C and kept for 5 minutes. Then, the fragrance gel is filled into the fiber skeleton layer. After cooling, a composite sheet is obtained.

[0048] The prepared composite sheet is embossed, folded, and gathered to form a continuous cylindrical strip with multiple longitudinal channels and uniformity. It is then cut into a cylinder with a porous surface and a length of 144 mm. Further cutting into segments with a length of 20 mm yields the flavoring unit.

[0049] The flavor-enhancing unit can be combined with other filter rods to prepare cigarette filter rods using conventional methods.

[0050] Example 3

[0051] Preparation of modified polylactic acid nanofibers:

[0052] After the dried polycaprolactone granules and polylactic acid granules were mixed evenly at a mass ratio of 9:4, they were placed in a micro-mixing rheometer and melt-processed for 8 minutes at a speed of 65 rpm and a temperature of 160°C. The resulting mixture was then added to 50... In a mixture of polycaprolactone and 1,4-dioxane, the temperature was raised to 75°C and stirred until no visible particles were found. Gallic acid and acetic anhydride were added, with a mass ratio of polycaprolactone, gallic acid, and acetic anhydride of 10:1:0.1. Under a nitrogen atmosphere, the temperature was raised to 110°C and stirred for 2 hours. After the reaction was completed, the mixture was cooled to room temperature, filtered, and the resulting solid was freeze-dried and then dissolved in hexafluoroisopropanol. Porous nano-silica with a mass of 0.12 times that of polycaprolactone was added, and the mixture was ultrasonically dispersed to obtain a spinning solution with a polycaprolactone mass fraction of 8%. The spinning solution was transferred to a syringe, and electrospinning was performed under the conditions of a feed rate of 0.6 ml / h, a spinning static voltage of 20 kV, and a receiving distance of 15 cm to obtain modified polylactic acid nanofibers.

[0053] Preparation of fiber web:

[0054] Modified polylactic acid (PLA) nanofibers were aggregated to form PLA nanofiber bundles with a diameter of 0.11-0.13 mm. The polycaprolactone (PVC) nanofiber bundles were then woven into a mesh using a braiding machine. The mesh was then microwaved at 650 W for 20 minutes. Afterward, it was placed in a low-temperature plasma device with air as the working gas and subjected to low-temperature plasma treatment at a discharge power of 150 W for 5 minutes. The plasma was then discharged at a rate of 4 ml / cm². 2 A 1 wt% chitosan solution was sprayed onto the fiber and then dried under infrared light heating to obtain a fiber web.

[0055] Preparation of composite sheets

[0056] In this embodiment, the composite sheet uses a nonwoven fabric as the nonwoven surface layer, obtained by spunbonding and spot bonding thermal rolling of methyl methacrylate and polylactic acid materials in a 1:1 mass ratio, with a corresponding basis weight of 40 g / m². 2 .

[0057] Preparation of the fiber skeleton layer: The three layers of the prepared fiber mesh are overlapped together, leaving one side open. The remaining edges are bonded together by hot pressing. Then, the fiber mesh is soaked in deionized water, and the amount of deionized water is just enough to completely submerge the fiber mesh. Dioctadecyl dimethyl ammonium chloride is added, and after stirring for 15 minutes, sodium pyrophosphate is added. The mass ratio of deionized water, dioctadecyl dimethyl ammonium chloride, and sodium pyrophosphate is 10:0.5:3. The fiber skeleton layer is ultrasonically treated for 4 hours under intermittent pulsed ultrasound at a frequency of 25KHz and a power of 100W. After removal, the fiber skeleton layer is naturally air-dried. In this embodiment, the pulse working time of the intermittent pulsed ultrasound is 3s, and the pulse interval time is 5s.

[0058] Filling: The prepared fiber skeleton layer is heated to 30°C, covered with a non-woven fabric surface layer, and then covered with a non-woven fabric surface layer on the outermost side. The temperature is raised to 70°C and kept for 5 minutes. Then, the fragrance gel is filled into the fiber skeleton layer. After cooling, a composite sheet is obtained.

[0059] The prepared composite sheet is embossed, folded, and gathered to form a continuous cylindrical strip with multiple longitudinal channels and uniformity. It is then cut into a cylinder with a porous surface and a length of 144 mm. Further cutting into segments with a length of 20 mm yields the flavoring unit.

[0060] The flavor-enhancing unit can be combined with other filter rods to prepare cigarette filter rods using conventional methods.

[0061] The above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the present invention, and all such modifications and substitutions should be covered within the scope of the claims of the present invention. Technical aspects, shapes, and structures not described in detail in this invention are all well-known technologies.

Claims

1. A flavor-enhancing unit, characterized in that, The flavoring unit is a cylindrical structure with longitudinal multi-channels formed by embossing, folding, or gathering a composite sheet. The composite sheet includes a fiber skeleton layer, a flavoring gel filled within the fiber skeleton layer, and a non-woven fabric surface layer covering the fiber skeleton layer. The fiber skeleton layer comprises two or more overlapping fiber webs; the fiber web is woven from modified polylactic acid nanofibers. The preparation method of the composite sheet is as follows: Preparation of the fiber skeleton layer: The three layers of the prepared fiber web are overlapped together, leaving one side open. The remaining edge parts are bonded together by hot pressing. Then, it is soaked in deionized water, and bis(octadecyl)dimethylammonium chloride is added. After stirring for 10-20 minutes, sodium pyrophosphate is added, and the mixture is ultrasonically treated under intermittent pulsed ultrasound for 4-6 hours. After taking it out, it is washed in deionized water by shaking until neutral. After taking it out, it is air-dried to obtain the fiber skeleton layer. Filling: Heat the prepared fiber skeleton layer to 30-35℃, cover it with a non-woven fabric surface layer, cover the outermost non-woven fabric surface layer, heat it to 60-70℃, keep it at that temperature for 5 minutes, then fill the fiber skeleton layer with fragrance gel, and obtain a composite sheet after cooling.

2. The flavor-enhancing unit according to claim 1, characterized in that, The modified polylactic acid nanofibers are made by electrospinning polylactic acid, polycaprolactone, porous nano-silica, and gallic acid as the main raw materials.

3. A flavoring unit according to claim 1 or 2, characterized in that, The nonwoven fabric surface layer is made of biodegradable material using hydroentangling, needle punching, or hot rolling processes, with a corresponding basis weight of 25-40 g / m². 2 .

4. The flavor-enhancing unit according to claim 3, characterized in that, The biodegradable material is made from one or more of polylactic acid, chitin, polyester, cellulose acetate, gelatin, and chitosan.

5. A flavor-enhancing unit according to claim 4, characterized in that, The method for preparing the fiber web is as follows: modified polylactic acid nanofibers are aggregated to form modified polylactic acid nanofiber bundles with a diameter of 0.1-0.15 mm. Polycaprolactone nanofiber bundles are woven into a web using a weaving machine. The web is then placed in a microwave oven for microwave treatment for 15-20 min. After being removed and subjected to low-temperature plasma treatment, chitosan solution is sprayed on the web. Finally, the web is dried under infrared light heating to obtain the fiber web modified polylactic acid nanofibers.

6. The flavor-enhancing unit according to claim 5, characterized in that, The modified polylactic acid nanofibers are prepared as follows: dried polycaprolactone particles and polylactic acid particles are mixed evenly and placed in a micro-mixing rheometer. The mixture is melt-processed for 5-10 minutes at a speed of 65 rpm and a temperature of 150-170℃. The resulting mixture is added to 1,4-dioxane and heated to 70-80℃. The mixture is stirred until no visible particles are found. Gallic acid and acetic anhydride are added. The mixture is heated to 110-120℃ under a nitrogen atmosphere and stirred for 2-3 hours. After the reaction is completed, the mixture is cooled to room temperature, filtered, and the resulting solid is freeze-dried and dissolved in hexafluoroisopropanol. Porous nano-silica is added to obtain a spinning solution with a mass fraction of 8%. The spinning solution is transferred to a syringe and electrospun to obtain modified polylactic acid nanofibers.

7. A cigarette filter rod, characterized in that, Includes the flavoring unit as described in any one of claims 1-6.