Polylactic acid tow for cigarettes and preparation method thereof

Abstract

The invention discloses a polylactic acid tow for cigarettes and a preparation method thereof, and belongs to the technical field of polylactic acid fiber preparation, polylactic acid resin, citric acid modified hydroxyapatite and a GTP / ZIF-90 material are mixed, melted and spun to prepare the polylactic acid tow, the polylactic acid tow has excellent adsorption and filtration performance on harmful ingredients in cigarette smoke, and the adsorption and filtration performance is good. And the material has excellent mechanical properties and thermal stability, and is not easy to fracture and collapse. Hydroxyapatite in the raw materials is subjected to surface modification with citric acid, a porous MOF material is used for loading and coating tea polyphenol to prepare a GTP / ZIF-90 material, the compatibility of hydroxyapatite and polylactic acid is improved, and meanwhile, polylactic acid tows can be endowed with good adsorption performance, antibacterial performance and biodegradability; the toxicity of cigarette smoke is further reduced through the synergistic effect of the tea polyphenol and the citric acid, the prepared polylactic acid tow for the cigarettes is excellent in comprehensive performance, and wide application of the polylactic acid tow in the field of cigarette filter tips can be promoted.

Description

Technical Field

[0001] The invention belongs to the technical field of polylactic acid fiber preparation, and in particular relates to a polylactic acid tow for cigarettes and a preparation method thereof. Background Art

[0002] With the development of cigarettes, smokers' requirements for cigarettes have gradually increased. Since the smoke emitted when cigarettes burn contains tar and nicotine, which are harmful to human health, cigarette filters are required to intercept harmful components in the smoke. In the traditional cigarette industry, the mainstream filter material is acetate fiber, and the main material used in cigarettes is diacetate, also known as diacetate fiber. In addition, polypropylene fiber is also used, but because its performance is not as good as acetate fiber, it is only used in low-end cigarettes. Cellulose diacetate tow cigarette filters for cigarettes have the advantages of being non-toxic, odorless, good adsorption effect, firm texture, high efficiency in intercepting smoke tar, and good elasticity and thermal stability. Therefore, cellulose diacetate tow is widely used in the tobacco industry.

[0003] However, due to the defects of insufficient raw material resources, complicated production process and high cost of acetate fiber, the price of prepared cigarette products is relatively expensive, which creates an economic burden on consumers. In recent years, polylactic acid fiber tows have gradually replaced acetate fiber tows. Polylactic acid fiber tows have good degradability and smoke and taste similar to acetate fiber filters, which can meet consumer needs. However, pure polylactic acid fiber tows have lower hardness and strength than acetate fiber tows. The prepared cigarette filters are prone to bending and breaking, resulting in increased resistance to inhalation, and the adsorption and filtration effect of harmful components is not as good as acetate fiber, resulting in low consumer satisfaction. Summary of the invention

[0004] The purpose of the present invention is to provide a polylactic acid tow for cigarettes and a preparation method thereof, so as to improve the adsorption and filtration performance and mechanical properties of the polylactic acid tow and reduce the release of harmful components.

[0005] The purpose of the present invention can be achieved through the following technical solutions:

[0006] The present invention provides a polylactic acid tow for cigarettes, which comprises the following raw materials by weight: 80-100 parts of polylactic acid resin, 10-20 parts of citric acid-modified hydroxyapatite, 4-20 parts of GTP / ZIF-90 material, and 0.1-1 part of lubricant;

[0007] Hydroxyapatite is a natural mineralization of calcium apatite (Ca5(PO4)3(OH)) with excellent biocompatibility, high hardness and good thermal stability. Its structure contains calcium ions and abundant hydroxyl groups.

[0008] The GTP / ZIF-90 material is a ZIF-90 metal organic framework loaded with tea polyphenols.

[0009] The ZIF-90 metal-organic framework contains imidazole groups, aldehyde groups and divalent zinc ions. The imidazole groups have an antibacterial effect. The aldehyde groups on them form hydrogen bonds with the hydroxyl groups in the polylactic acid resin, promoting the dispersion of the GTP / ZIF-90 material. The porous structure of the ZIF-90 metal-organic framework can improve the adsorption performance of the fiber bundle for tiny particles and harmful components in cigarette smoke. Since the aldehyde groups in its structure are strong adsorption sites for polar substances, it has a high adsorption performance for aldehyde compounds.

[0010] Furthermore, the preparation steps of the citric acid-modified hydroxyapatite are as follows:

[0011] The hydroxyapatite was added to anhydrous ethanol, ultrasonically dispersed for 20-30 minutes, placed in a microwave oven at 500-600W for 3-5 minutes to form a uniform suspension, citric acid was added to the suspension, stirred and mixed at 50-60°C for 3-5 hours, filtered and dried to obtain citric acid-modified hydroxyapatite.

[0012] The hydrophobicity of polylactic acid leads to its poor compatibility with hydroxyapatite. Hydroxyapatite is modified by citric acid, and the carboxyl group in the citric acid molecule and the hydroxyl group of hydroxyapatite undergo esterification reaction. Citric acid achieves surface modification of hydroxyapatite. Citric acid and polylactic acid have good compatibility. After citric acid modification, the compatibility of hydroxyapatite in polylactic acid can be improved, uniform dispersion can be achieved, the surface roughness of polylactic acid fiber can be increased, the contact area with tiny particles in the flue gas can be increased, and the adsorption and filtration effect can be improved. After citric acid modification, the citrate particles adsorbed on the surface have a strong negative charge, which can promote the adsorption of positively charged metal ions.

[0013] Hydroxyapatite can effectively adsorb a variety of radioactive nuclides due to its high specific surface area and porous structure. Cigarette smoke contains polonium-210, which is an extremely toxic nuclide. After polonium enters the body and produces internal irradiation, it will cause radioactive damage to internal organs. A large dose of irradiation can cause severe radiation sickness or even death. By adding modified hydroxyapatite to polylactic acid tow and utilizing its adsorption effect, the content of polonium-210 entering the human body can be reduced.

[0014] Furthermore, the mass ratio of the hydroxyapatite to the citric acid is 20:3-5.

[0015] Furthermore, the particle size of the hydroxyapatite is 100-200 nm.

[0016] Furthermore, the preparation steps of the GTP / ZIF-90 material are as follows:

[0017] The tea polyphenols are dissolved in water to form a solution, and the ZIF-90 metal organic framework is added thereto. The mixture is stirred and allowed to stand for 8-10 hours, and then filtered, washed and dried to obtain the GTP / ZIF-90 material.

[0018] The ZIF-90 metal organic framework is a porous MOF material. It is a material with a SOD topological structure obtained by the reaction of Zn(Ⅱ) and imidazole-2-carboxaldehyde (ICA). It has good thermal and chemical stability. Due to its high specific surface area, it can adsorb functional molecules on the external surface or open channels and trap these molecules in the framework to achieve the loading of functional molecules.

[0019] Tea polyphenols are powdery at room temperature, and have antioxidant, radiation protection and antibacterial functions. They can remove free radicals, and have metal chelation, which can form a tight bond with metal organic frameworks and is not easy to fall off. The tannins in tea polyphenols can form a non-toxic complex with nicotine, reducing the toxicity of nicotine, and tea polyphenols can eliminate bad breath. However, tea polyphenols are easily decomposed by light. Through the encapsulation of the ZIF-90 metal organic framework, rapid decomposition can be avoided and the action time can be prolonged.

[0020] Furthermore, the mass ratio of the tea polyphenols to the ZIF-90 metal organic framework is 1-2:5.

[0021] Furthermore, the specific surface area of ​​the ZIF-90 metal organic framework is 1000-1200m 2 / g, pore size is 1-3nm, particle size is 50-150nm. The larger specific surface area of ​​ZIF-90 metal organic framework can increase the loading capacity.

[0022] Furthermore, the lubricant is one of lauryl alcohol, silicone oil and white oil. Hydroxyapatite and ZIF-90 metal organic framework exist in the form of particles during the melt spinning process. To avoid clogging the spinneret, a lubricant can be added to reduce friction and reduce cleaning work during the spinning process.

[0023] The present invention also provides a method for preparing a polylactic acid tow for cigarettes, comprising the following steps:

[0024] Step 1: uniformly mix polylactic acid resin, citric acid-modified hydroxyapatite, GTP / ZIF-90 material and lubricant, and put them into a screw extruder for melt spinning to obtain a semi-finished tow;

[0025] Step 2: Stretch, curl and dry the semi-finished tow to obtain the polylactic acid tow for cigarettes.

[0026] Furthermore, the melt spinning temperature is 190-200°C.

[0027] Furthermore, the number of curls is 20-25 / 25mm, and the curling rate is 20-30%.

[0028] Furthermore, the linear density of the filament bundle is 5-6 ktex, and the linear density of the single filament is 4-5 dtex.

[0029] Beneficial effects of the present invention:

[0030] (1) The present invention prepares a polylactic acid tow by melt spinning a mixture of polylactic acid resin, citric acid-modified hydroxyapatite and GTP / ZIF-90 material (ZIF-90 metal organic framework loaded with tea polyphenols). The polylactic acid tow has excellent adsorption and filtration performance for harmful components in cigarette smoke, and has excellent mechanical properties and thermal stability and is not easy to break or collapse.

[0031] (2) In the present invention, the hydroxyapatite is surface-modified with citric acid to improve the compatibility of hydroxyapatite and polylactic acid, while improving its adsorption performance for radionuclides and metal ions, thereby reducing the damage of flue gas to the human body. In addition, the calcium ions rich in hydroxyapatite can improve the biodegradability of polylactic acid.

[0032] (3) The GTP / ZIF-90 material in the present invention is a ZIF-90 metal organic framework loaded with tea polyphenols. The porous MOF material is used to encapsulate tea polyphenols to avoid the decomposition of tea polyphenols during melt spinning and light decomposition, thereby improving stability. Tea polyphenols give the polylactic acid tow better antibacterial properties and can eliminate bad breath.

[0033] (4) The tea polyphenols and citric acid in the polylactic acid tow of the present invention can synergistically reduce the toxicity of cigarette smoke. The tea polyphenols can eliminate free radicals, and the citric acid can react with nicotine to generate nicotine salts, making it easier to deposit in the filter tow, thereby reducing the amount of nicotine inhaled by the human body. DETAILED DESCRIPTION

[0034] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0035] Example 1

[0036] Preparation of citric acid-modified hydroxyapatite:

[0037] Hydroxyapatite (100-200 nm) was added to anhydrous ethanol at a concentration of 1 g / L, ultrasonically dispersed for 20 min, and placed in a microwave oven at 600 W for 3 min to form a uniform suspension. Citric acid was added to the suspension at a mass ratio of hydroxyapatite to citric acid of 20:3. The mixture was stirred and mixed at 60°C for 3 h, and filtered and dried to obtain citric acid-modified hydroxyapatite.

[0038] Preparation of GTP / ZIF-90 material:

[0039] Tea polyphenols were dissolved in water at a concentration of 5 g / L to form a solution, and ZIF-90 metal organic framework was added. The mass ratio of tea polyphenols to ZIF-90 metal organic framework was 1:5. After stirring and mixing, the mixture was allowed to stand for 8 hours. After filtering, it was washed with deionized water for 3 times and dried to obtain GTP / ZIF-90 material. The specific surface area of ​​ZIF-90 metal organic framework was 1000-1200 m 2 / g, pore size is 1-3nm, and particle size is 50-150nm.

[0040] This embodiment provides a polylactic acid tow for cigarettes, which includes the following raw materials by weight: 100 parts of polylactic acid resin, 10 parts of citric acid-modified hydroxyapatite, 4 parts of GTP / ZIF-90 material, and 0.1 parts of silicone oil. The specific preparation steps are as follows:

[0041] Step 1: uniformly mix polylactic acid resin, citric acid-modified hydroxyapatite, GTP / ZIF-90 material and silicone oil, and put them into a screw extruder for melt spinning to obtain a semi-finished filament bundle, and set the melt spinning temperature to 190° C.;

[0042] Step 2: Stretch, curl and dry the semi-finished tow, with the curl number being 25 / 25mm and the curl rate being 20%, to obtain a polylactic acid tow for cigarettes.

[0043] Example 2

[0044] The only difference from Example 1 is that the mass ratio of hydroxyapatite to citric acid is 20:4. The specific steps are as follows:

[0045] Preparation of citric acid-modified hydroxyapatite:

[0046] Hydroxyapatite (100-200 nm) was added to anhydrous ethanol at a concentration of 1 g / L, ultrasonically dispersed for 25 min, and placed in a microwave oven at 600 W for 4 min to form a uniform suspension. Citric acid was added to the suspension at a mass ratio of hydroxyapatite to citric acid of 20:4. The mixture was stirred and mixed at 55°C for 4 h, and filtered and dried to obtain citric acid-modified hydroxyapatite.

[0047] Preparation of GTP / ZIF-90 material:

[0048] Tea polyphenols were dissolved in water at a concentration of 5 g / L to form a solution, and ZIF-90 metal organic framework was added. The mass ratio of tea polyphenols to ZIF-90 metal organic framework was 1:5. After stirring and mixing, the mixture was allowed to stand for 8 hours. After filtering, it was washed with deionized water for 3 times and dried to obtain GTP / ZIF-90 material. The specific surface area of ​​ZIF-90 metal organic framework was 1000-1200 m 2 / g, pore size is 1-3nm, and particle size is 50-150nm.

[0049] This embodiment provides a polylactic acid tow for cigarettes, which includes the following raw materials by weight: 100 parts of polylactic acid resin, 10 parts of citric acid-modified hydroxyapatite, 4 parts of GTP / ZIF-90 material, and 0.1 parts of silicone oil. The specific preparation steps are as follows:

[0050] Step 1: uniformly mix polylactic acid resin, citric acid-modified hydroxyapatite, GTP / ZIF-90 material and silicone oil, and put them into a screw extruder for melt spinning to obtain a semi-finished filament bundle, and set the melt spinning temperature to 190° C.;

[0051] Step 2: Stretch, curl and dry the semi-finished tow, with the curl number being 25 / 25mm and the curl rate being 20%, to obtain a polylactic acid tow for cigarettes.

[0052] Example 3

[0053] The only difference from Example 1 is that the mass ratio of hydroxyapatite to citric acid is 20:5. The specific steps are as follows:

[0054] Preparation of citric acid-modified hydroxyapatite:

[0055] Hydroxyapatite (100-200 nm) was added to anhydrous ethanol at a concentration of 1 g / L, ultrasonically dispersed for 30 min, and placed in a microwave oven at 600 W for 5 min to form a uniform suspension. Citric acid was added to the suspension at a mass ratio of hydroxyapatite to citric acid of 20:5. The suspension was stirred and mixed at 60°C for 5 h, and filtered and dried to obtain citric acid-modified hydroxyapatite.

[0056] Preparation of GTP / ZIF-90 material:

[0057] Tea polyphenols were dissolved in water at a concentration of 5 g / L to form a solution, and ZIF-90 metal organic framework was added. The mass ratio of tea polyphenols to ZIF-90 metal organic framework was 1:5. After stirring and mixing, the mixture was allowed to stand for 8 hours. After filtering, it was washed with deionized water for 3 times and dried to obtain GTP / ZIF-90 material. The specific surface area of ​​ZIF-90 metal organic framework was 1000-1200 m 2 / g, pore size is 1-3nm, and particle size is 50-150nm.

[0058] This embodiment provides a polylactic acid tow for cigarettes, which includes the following raw materials by weight: 100 parts of polylactic acid resin, 10 parts of citric acid-modified hydroxyapatite, 4 parts of GTP / ZIF-90 material, and 0.1 parts of silicone oil. The specific preparation steps are as follows:

[0059] Step 1: uniformly mix polylactic acid resin, citric acid-modified hydroxyapatite, GTP / ZIF-90 material and silicone oil, and put them into a screw extruder for melt spinning to obtain a semi-finished filament bundle, and set the melt spinning temperature to 190° C.;

[0060] Step 2: Stretch, curl and dry the semi-finished tow, with the curl number being 25 / 25mm and the curl rate being 20%, to obtain a polylactic acid tow for cigarettes.

[0061] Example 4

[0062] The only difference from Example 2 is that the mass ratio of tea polyphenols to ZIF-90 metal organic framework is 1.5:5. The specific steps are as follows:

[0063] Preparation of citric acid-modified hydroxyapatite:

[0064] Hydroxyapatite (100-200 nm) was added to anhydrous ethanol at a concentration of 1 g / L, ultrasonically dispersed for 25 min, and placed in a microwave oven at 600 W for 4 min to form a uniform suspension. Citric acid was added to the suspension at a mass ratio of hydroxyapatite to citric acid of 20:4. The mixture was stirred and mixed at 60°C for 4 h, and filtered and dried to obtain citric acid-modified hydroxyapatite.

[0065] Preparation of GTP / ZIF-90 material:

[0066] Tea polyphenols were dissolved in water at a concentration of 5 g / L to form a solution, and ZIF-90 metal organic framework was added. The mass ratio of tea polyphenols to ZIF-90 metal organic framework was 1.5:5. After stirring and mixing, the mixture was allowed to stand for 9 hours. After filtering, it was washed with deionized water for 3 times and dried to obtain GTP / ZIF-90 material. The specific surface area of ​​ZIF-90 metal organic framework was 1000-1200 m 2 / g, pore size is 1-3nm, and particle size is 50-150nm.

[0067] This embodiment provides a polylactic acid tow for cigarettes, which includes the following raw materials by weight: 100 parts of polylactic acid resin, 10 parts of citric acid-modified hydroxyapatite, 4 parts of GTP / ZIF-90 material, and 0.1 parts of silicone oil. The specific preparation steps are as follows:

[0068] Step 1: uniformly mix polylactic acid resin, citric acid-modified hydroxyapatite, GTP / ZIF-90 material and silicone oil, and put them into a screw extruder for melt spinning to obtain a semi-finished filament bundle, and set the melt spinning temperature to 190° C.;

[0069] Step 2: Stretch, curl and dry the semi-finished tow, with the curl number being 25 / 25mm and the curl rate being 20%, to obtain a polylactic acid tow for cigarettes.

[0070] Example 5

[0071] The only difference from Example 2 is that the mass ratio of tea polyphenols to ZIF-90 metal organic framework is 2.0:5. The specific steps are as follows:

[0072] Preparation of citric acid-modified hydroxyapatite:

[0073] Hydroxyapatite (100-200 nm) was added to anhydrous ethanol at a concentration of 1 g / L, ultrasonically dispersed for 25 min, and placed in a microwave oven at 600 W for 4 min to form a uniform suspension. Citric acid was added to the suspension at a mass ratio of hydroxyapatite to citric acid of 20:4. The mixture was stirred and mixed at 60°C for 4 h, and filtered and dried to obtain citric acid-modified hydroxyapatite.

[0074] Preparation of GTP / ZIF-90 material:

[0075] Tea polyphenols were dissolved in water at a concentration of 5 g / L to form a solution, and ZIF-90 metal organic framework was added. The mass ratio of tea polyphenols to ZIF-90 metal organic framework was 2.0:5. After stirring and mixing, the mixture was allowed to stand for 10 hours. After filtering, it was washed with deionized water for 3 times and dried to obtain GTP / ZIF-90 material. The specific surface area of ​​ZIF-90 metal organic framework is 1000-1200 m 2 / g, pore size is 1-3nm, and particle size is 50-150nm.

[0076] This embodiment provides a polylactic acid tow for cigarettes, which includes the following raw materials by weight: 100 parts of polylactic acid resin, 10 parts of citric acid-modified hydroxyapatite, 4 parts of GTP / ZIF-90 material, and 0.1 parts of silicone oil. The specific preparation steps are as follows:

[0077] Step 1: uniformly mix polylactic acid resin, citric acid-modified hydroxyapatite, GTP / ZIF-90 material and silicone oil, and put them into a screw extruder for melt spinning to obtain a semi-finished filament bundle, and set the melt spinning temperature to 190° C.;

[0078] Step 2: Stretch, curl and dry the semi-finished tow, with the curl number being 25 / 25mm and the curl rate being 20%, to obtain a polylactic acid tow for cigarettes.

[0079] Example 6

[0080] The only difference from Example 4 is that the amount of citric acid-modified hydroxyapatite in the raw material is adjusted to 16 parts.

[0081] This embodiment provides a polylactic acid tow for cigarettes, which includes the following raw materials by weight: 100 parts of polylactic acid resin, 16 parts of citric acid-modified hydroxyapatite, 4 parts of GTP / ZIF-90 material, and 0.1 parts of white oil. The specific preparation steps are as follows:

[0082] Step 1: uniformly mix polylactic acid resin, citric acid-modified hydroxyapatite, GTP / ZIF-90 material and silicone oil, and put them into a screw extruder for melt spinning to obtain a semi-finished filament bundle, and set the melt spinning temperature to 195° C.;

[0083] Step 2: Stretch, curl and dry the semi-finished tow, with the curl number being 25 / 25mm and the curl rate being 20%, to obtain a polylactic acid tow for cigarettes.

[0084] Example 7

[0085] The only difference from Example 4 is that the amount of citric acid-modified hydroxyapatite in the raw material is adjusted to 20 parts.

[0086] This embodiment provides a polylactic acid tow for cigarettes, which includes the following raw materials by weight: 100 parts of polylactic acid resin, 20 parts of citric acid-modified hydroxyapatite, 4 parts of GTP / ZIF-90 material, and 0.1 parts of dodecanol. The specific preparation steps are as follows:

[0087] Step 1: uniformly mix polylactic acid resin, citric acid-modified hydroxyapatite, GTP / ZIF-90 material and silicone oil, and put them into a screw extruder for melt spinning to obtain a semi-finished filament bundle, and set the melt spinning temperature to 200° C.;

[0088] Step 2: Stretch, curl and dry the semi-finished tow, with the curl number being 25 / 25mm and the curl rate being 20%, to obtain a polylactic acid tow for cigarettes.

[0089] Example 8

[0090] The only difference from Example 6 is that the number of parts of the GTP / ZIF-90 material is adjusted to 10 parts.

[0091] This embodiment provides a polylactic acid tow for cigarettes, which includes the following raw materials by weight: 100 parts of polylactic acid resin, 16 parts of citric acid-modified hydroxyapatite, 10 parts of GTP / ZIF-90 material, and 0.1 parts of white oil. The specific preparation steps are as follows:

[0092] Step 1: uniformly mix polylactic acid resin, citric acid-modified hydroxyapatite, GTP / ZIF-90 material and silicone oil, and put them into a screw extruder for melt spinning to obtain a semi-finished filament bundle, and set the melt spinning temperature to 200° C.;

[0093] Step 2: Stretch, curl and dry the semi-finished tow, with the curl number being 25 / 25mm and the curl rate being 20%, to obtain a polylactic acid tow for cigarettes.

[0094] Example 9

[0095] The only difference from Example 6 is that the number of parts of the GTP / ZIF-90 material is adjusted to 20 parts.

[0096] This embodiment provides a polylactic acid tow for cigarettes, which includes the following raw materials by weight: 100 parts of polylactic acid resin, 16 parts of citric acid-modified hydroxyapatite, 20 parts of GTP / ZIF-90 material, and 0.1 parts of white oil. The specific preparation steps are as follows:

[0097] Step 1: uniformly mix polylactic acid resin, citric acid-modified hydroxyapatite, GTP / ZIF-90 material and silicone oil, and put them into a screw extruder for melt spinning to obtain a semi-finished filament bundle, and set the melt spinning temperature to 200° C.;

[0098] Step 2: Stretch, curl and dry the semi-finished tow, with the curl number being 25 / 25mm and the curl rate being 20%, to obtain a polylactic acid tow for cigarettes.

[0099] Comparative Example 1

[0100] Compared with Example 1, the raw material in this comparative example is replaced by an equal mass of GTP / ZIF-90 material to replace the citric acid-modified hydroxyapatite.

[0101] This comparative example provides a polylactic acid tow for cigarettes, which includes the following raw materials by weight: 100 parts of polylactic acid resin, 14 parts of GTP / ZIF-90 material, and 0.5 parts of silicone oil. The specific preparation steps are as follows:

[0102] Step 1: Evenly mix the polylactic acid resin, GTP / ZIF-90 material and silicone oil, and put them into a screw extruder for melt spinning to obtain a semi-finished tow, and set the melt spinning temperature to 190° C.;

[0103] Step 2: Stretch, curl and dry the semi-finished tow, with the curl number being 25 / 25mm and the curl rate being 20%, to obtain a polylactic acid tow for cigarettes.

[0104] Comparative Example 2

[0105] Compared with Example 1, the raw material in this comparative example is replaced by an equal mass of citric acid-modified hydroxyapatite instead of GTP / ZIF-90 material.

[0106] This comparative example provides a polylactic acid tow for cigarettes, which includes the following raw materials by weight: 100 parts of polylactic acid resin, 14 parts of citric acid-modified hydroxyapatite, and 0.1 parts of silicone oil. The specific preparation steps are as follows:

[0107] Step 1: uniformly mix polylactic acid resin, citric acid-modified hydroxyapatite and silicone oil, and put them into a screw extruder for melt spinning to obtain a semi-finished tow, and set the melt spinning temperature to 190° C.;

[0108] Step 2: Stretch, curl and dry the semi-finished tow, with the curl number being 25 / 25mm and the curl rate being 20%, to obtain a polylactic acid tow for cigarettes.

[0109] Comparative Example 3

[0110] Compared with Example 1, the citric acid-modified hydroxyapatite in the raw materials of this comparative example is replaced by an equal mass of hydroxyapatite, and the GTP / ZIF-90 material is replaced by an equal mass of ZIF-90 metal organic framework.

[0111] The comparative example provides a polylactic acid tow for cigarettes, which comprises the following raw materials by weight: 100 parts of polylactic acid resin, 10 parts of hydroxyapatite (100-200 nm), 4 parts of ZIF-90 metal organic framework, and 0.1 parts of silicone oil, wherein the specific surface area of ​​the ZIF-90 metal organic framework is 1000-1200 m 2 / g, pore size is 1-3nm, particle size is 50-150nm. The specific preparation steps are as follows:

[0112] Step 1, polylactic acid resin, hydroxyapatite, ZIF-90 metal organic framework and silicone oil are uniformly mixed, and put into a screw extruder for melt spinning to obtain a semi-finished filament bundle, and the melt spinning temperature is set to 200° C.;

[0113] Step 2: Stretch, curl and dry the semi-finished tow, with the curl number being 25 / 25mm and the curl rate being 20%, to obtain a polylactic acid tow for cigarettes.

[0114] Comparative Example 4

[0115] Compared with Example 1, the raw materials of this comparative example do not contain citric acid-modified hydroxyapatite and GTP / ZIF-90 material.

[0116] This comparative example provides a polylactic acid tow for cigarettes, which includes the following raw materials by weight: 100 parts of polylactic acid resin and 0.1 parts of silicone oil. The specific preparation steps are as follows:

[0117] Step 1: uniformly mix the polylactic acid resin and the silicone oil, and put them into a screw extruder for melt spinning to obtain a semi-finished filament bundle, and set the melt spinning temperature to 200° C.;

[0118] Step 2: Stretch, curl and dry the semi-finished tow, with the curl number being 25 / 25mm and the curl rate being 20%, to obtain a polylactic acid tow for cigarettes.

[0119] The performance of the polylactic acid tows for cigarettes prepared in Examples 1 to 9 and Comparative Examples 1 to 4 was tested, and the prepared polylactic acid tows were opened with an opening width of 20 cm, and triacetin was added as a binder for gluing with a gluing amount of 7%. The tows were formed by a filter rod forming machine and cured to obtain filter rods for cigarettes. The adsorption performance of the filter rods on harmful components in cigarettes was tested, and the results are shown in Table 1.

[0120] The filter rod hardness and indentation amount test are tested with reference to GB / T 22838.6-2024 Determination of physical properties of cigarettes and filter rods Part 6: Hardness.

[0121] Table 1

[0122]

[0123]

[0124] It can be seen from Table 1 that in Examples 1 to 3, when the citric acid loading is increased, the filter rod obtained by the prepared filament bundle has improved adsorption and filtration performance for harmful components in flue gas. The addition of tea polyphenol loading in Examples 4 and 5 significantly improves the adsorption and filtration performance for NNK. In Examples 6 to 9, the proportion of citric acid-modified hydroxyapatite or GTP / ZIF-90 in the raw materials is increased. Since the doping amount of the modified porous material in the filament bundle is increased, the filter rod has better mechanical properties, is not easy to break and collapse, has stronger adsorption and filtration performance for harmful components, and reduces the harm to the human body. It can be seen from the results of the comparative examples that the filament bundles prepared in Comparative Examples 1 to 4 have obviously inferior comprehensive performance to the embodiments of the present invention.

[0125] It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device.

[0126] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A polylactic acid tow for cigarettes, characterized in that: The following raw materials are included by weight: 80-100 parts of polylactic acid resin, 10-20 parts of citric acid modified hydroxyapatite, 4-20 parts of GTP / ZIF-90 material, and 0.1-1 parts of lubricant; The GTP / ZIF-90 material is a ZIF-90 metal organic framework loaded with tea polyphenols.

2. The polylactic acid tow for cigarettes according to claim 1, characterized in that: The preparation steps of the citric acid-modified hydroxyapatite are as follows: The hydroxyapatite was added to anhydrous ethanol, ultrasonically dispersed for 20-30 minutes, placed in a microwave oven at 500-600W for 3-5 minutes to form a uniform suspension, citric acid was added to the suspension, stirred and mixed at 50-60°C for 3-5 hours, filtered and dried to obtain citric acid-modified hydroxyapatite.

3. The polylactic acid tow for cigarettes according to claim 2, characterized in that: The mass ratio of the hydroxyapatite to the citric acid is 20:3-5.

4. The polylactic acid tow for cigarettes according to claim 2, characterized in that: The particle size of the hydroxyapatite is 100-200 nm.

5. The polylactic acid tow for cigarettes according to claim 1, characterized in that: The preparation steps of the GTP / ZIF-90 material are as follows: The tea polyphenols are dissolved in water to form a solution, and the ZIF-90 metal organic framework is added thereto. The mixture is stirred and allowed to stand for 8-10 hours, and then filtered, washed and dried to obtain the GTP / ZIF-90 material.

6. The polylactic acid tow for cigarettes according to claim 5, characterized in that: The mass ratio of the tea polyphenols to the ZIF-90 metal organic framework is 1-2:

5.

7. The polylactic acid tow for cigarettes according to claim 5, characterized in that: The specific surface area of ​​the ZIF-90 metal organic framework is 1000-1200m 2 / g, pore size is 1-3nm, and particle size is 50-150nm.

8. The polylactic acid tow for cigarettes according to claim 1, characterized in that: The lubricant is one of lauryl alcohol, silicone oil and white oil.

9. A method for preparing a polylactic acid tow for cigarettes according to any one of claims 1 to 8, characterized in that: The following steps are involved: Step 1: uniformly mix polylactic acid resin, citric acid-modified hydroxyapatite and GTP / ZIF-90 material, and put them into a screw extruder for melt spinning to obtain a semi-finished tow; Step 2: Stretch, curl and dry the semi-finished tow to obtain the polylactic acid tow for cigarettes.

10. The method for preparing a polylactic acid tow for cigarettes according to claim 9, characterized in that: The temperature of the melt spinning is 190-200°C.

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