Degradable cooling and heat-insulating porous material, preparation method and application thereof

Abstract

This invention provides a biodegradable cooling and heat-insulating porous material, its preparation method, and its application. The raw materials include: 82-88 parts biodegradable cellulose, 35-45 parts polylactic acid, 3-5 parts silane coupling agent-modified aramid fiber, 4-8 parts functional particles, and a pore-forming agent. The pore-forming agent is selected from water-soluble salts. The mass ratio of the pore-forming agent to polylactic acid is 1.3-1.6:1. The functional particles include a polymer, alumina, ceramic microspheres, ceramic fibers, diatomaceous earth, and white oil in a mass ratio of (10-15):(3-5):(3-5):(3-5):(3-5):(0.1-0.5). In this invention, the biodegradable cellulose exhibits good mechanical properties and flame-retardant and high-temperature resistance, which can improve the high-temperature and high-humidity mechanical properties of porous materials and is beneficial to the stability of the porous structure. In particular, the addition of functional particles composed of specific raw materials has a significant cooling effect while ensuring smooth suction.

Description

Technical Field

[0001] This invention belongs to the field of porous materials technology, and particularly relates to a biodegradable cooling and heat-insulating porous material, its preparation method and its application. Background Technology

[0002] Tobacco filter materials are mostly made of cellulose diacetate, which decomposes more slowly than natural cellulose. Cigarette filters made of cellulose acetate may take up to 15 years to decompose completely. After smoking, cigarette filters are usually discarded into the environment and are one of the most common forms of man-made waste.

[0003] Filter rods made of polylactic acid (PLA) material exhibit excellent biodegradability. Patent CN109846084A discloses a PLA filament composite filter rod, comprising several PLA filaments, several fillers, and filter rod forming paper. The filter rod is axially formed by tightly stacking several PLA filaments and fillers. This patent uses biodegradable PLA filaments; however, its process is complex, and the material's mechanical properties are relatively poor. On the other hand, during cigarette smoking, the heat generated by the cigarette's combustion cone is carried to the filter by the mainstream smoke. As smoking progresses, the temperature of the smoke passing through the filter gradually increases. Near the end of the smoking process, the smoke temperature at the filter tip can reach as high as 70-80°C. Excessively high filter temperatures affect the filter's retention effect and also impact consumers' perception of the smoke's sensory quality.

[0004] Therefore, improvements are still needed in how to enhance the cooling performance of cigarette filter rod materials while meeting environmental requirements such as biodegradability. Summary of the Invention

[0005] In view of this, the purpose of the present invention is to provide a biodegradable cooling and heat-insulating porous material, its preparation method and its application, wherein the cigarette filter rod prepared by the porous material has good cooling and heat insulation properties.

[0006] This invention provides a biodegradable cooling and heat-insulating porous material, the raw materials for which are prepared by weight include the following components:

[0007] 82-88 parts biodegradable cellulose, 35-45 parts polylactic acid, 3-5 parts silane coupling agent modified aramid fiber, 4-8 parts functional particles and pore-forming agent;

[0008] The porogen is selected from water-soluble salts; the mass ratio of the porogen to polylactic acid is 1.3 to 1.6:1;

[0009] The functional particles comprise polymers, alumina, ceramic microspheres, ceramic fibers, diatomaceous earth, and white oil in a mass ratio of (10-15):(3-5):(3-5):(3-5):(3-5):(0.1-0.5).

[0010] Preferably, the polymer is selected from one or more of polyethylene, polyurethane, polylactic acid, and polyethylene oxide.

[0011] Preferably, the silane coupling agent modified aramid fiber is obtained by placing aramid fiber in a silane coupling agent, soaking it for 10-30 minutes, and then drying it.

[0012] The mass ratio of the aramid fiber to the silane coupling agent is 1:9 to 11.

[0013] Preferably, the particle size of the porogen is 50–400 μm.

[0014] Preferably, the water-soluble salt is selected from one or more of sodium chloride, sodium citrate, and calcium carbonate.

[0015] Preferably, the raw materials for preparation also include a pore-connecting agent; the pore-connecting agent is selected from one or more of polyacrylamide, polyethylene glycol, and polyethylene oxide.

[0016] Preferably, the functional particles comprise polyethylene, alumina, ceramic microspheres, ceramic fibers, diatomaceous earth, and white oil in a mass ratio of 10:3:5:3:3:0.1.

[0017] Or it may include polyurethane, alumina, ceramic microspheres, ceramic fibers, diatomaceous earth and white oil in a mass ratio of 13:4:4.5:4:4:0.35;

[0018] Or it may include polylactic acid, alumina, ceramic microspheres, ceramic fibers, diatomaceous earth and white oil in a mass ratio of 15:5:3:5:5:0.5.

[0019] This invention provides a method for preparing the biodegradable cooling and heat-insulating porous material described in the above technical solution, comprising the following steps:

[0020] A premix is ​​prepared by mixing biodegradable cellulose, polylactic acid, silane coupling agent-modified aramid fiber, pore-forming agent, and functional particles.

[0021] The premixed material is melt-extruded to obtain a biodegradable cooling and heat-insulating porous material.

[0022] Preferably, the extrusion is performed using a twin-screw extruder with a screw length-to-diameter ratio of 40:1;

[0023] The extrusion vacuum degree is greater than -0.6MPa;

[0024] The extrusion head temperature is 180-220℃, the middle section temperature is 200-220℃, and the die head temperature is 190-210℃.

[0025] This invention provides a tobacco filter rod comprising the biodegradable cooling and heat-insulating porous material described in the above technical solution.

[0026] This invention provides a biodegradable cooling and heat-insulating porous material. The raw materials, by weight, comprise the following components: 82-88 parts biodegradable cellulose, 35-45 parts polylactic acid, 3-5 parts silane coupling agent modified aramid fiber, 4-8 parts functional particles, and a pore-forming agent. The pore-forming agent is selected from water-soluble salts. The mass ratio of the pore-forming agent to polylactic acid is 1.3-1.6:1. The functional particles comprise a polymer, alumina, ceramic microspheres, ceramic fibers, diatomaceous earth, and white oil in a mass ratio of (10-15):(3-5):(3-5):(3-5):(3-5):(0.1-0.5). This invention uses polylactic acid and biodegradable cellulose as the main body of a porous structure, and combines a certain amount of modified aramid fiber and cooling and heat-insulating functional particles. Biodegradable cellulose has good mechanical properties and flame-retardant and high-temperature resistance properties, which can improve the high-temperature and high-humidity mechanical properties of porous composite materials and is beneficial to the stability of porous structures. In particular, the addition of functional particles composed of specific raw materials has a significant cooling effect, while ensuring smooth suction. Detailed Implementation

[0027] This invention provides a biodegradable cooling and heat-insulating porous material, the raw materials for which are prepared by weight include the following components:

[0028] 82-88 parts biodegradable cellulose, 35-45 parts polylactic acid, 3-5 parts silane coupling agent modified aramid fiber, 4-8 parts functional particles and pore-forming agent;

[0029] The porogen is selected from water-soluble salts; the mass ratio of the porogen to polylactic acid is 1.3 to 1.6:1;

[0030] The functional particles comprise polymers, alumina, ceramic microspheres, ceramic fibers, diatomaceous earth, and white oil in a mass ratio of (10-15):(3-5):(3-5):(3-5):(3-5):(0.1-0.5).

[0031] This invention uses polylactic acid and biodegradable cellulose as the main body of a porous structure, and combines a certain amount of modified aramid fiber and functional particles. Biodegradable cellulose has good mechanical properties and flame retardant and high temperature resistance, which can improve the high temperature and high humidity mechanical properties of porous composite materials and is beneficial to the stability of porous structures. In particular, the addition of functional particles has a significant cooling effect, while ensuring smooth suction.

[0032] The raw material for preparing the biodegradable cooling and heat-insulating porous material of this invention includes biodegradable cellulose. The numerous hydroxyl groups on the surface of the biodegradable cellulose, as well as the carboxyl groups and ester bonds of polylactic acid and other polar groups, have a good adsorption effect on functional particles, which is beneficial for the molding, processing, and preparation of the porous material, and the functional particles are not easily detached. The biodegradable cellulose is selected from one or more of cotton nanofibers, bamboo nanofibers, and chitosan nanofibers, preferably chitosan nanofibers.

[0033] This invention preferably employs a porogen method to prepare porous materials. The raw materials include a porogen; the porogen is selected from water-soluble salts; the water-soluble salt is selected from one or more of sodium chloride, sodium citrate, and calcium carbonate. The mass ratio of the porogen to polylactic acid is 1.3–1.6:1, preferably 1.4:1. The particle size of the porogen is 50–400 μm, preferably 120–180 μm. In a specific embodiment, the porogen is sodium chloride with a particle size of 100–200 μm. Since porous materials prepared using porogens typically have poor connectivity between internal pores, which can easily affect the mechanical properties of the porous material, especially when functional particles are added, this invention uses the above-mentioned types of porogens, combined with the selection of material particle size and dosage, and the coordination with a pore-connecting agent, to form a composite porogen system, which is then melt-blended to obtain a porous material with connectivity. The pore-connecting agent is selected from one or more of polyacrylamide, polyethylene glycol, and polyethylene oxide. In this invention, the weight ratio of the pore-connecting agent to the pore-forming agent is 1:2 to 4.

[0034] The raw materials for preparing the biodegradable cooling and heat-insulating porous material of this invention include aramid fibers modified with a silane coupling agent. The silane coupling agent-modified aramid fibers are obtained by immersing aramid fibers in a silane coupling agent for 10-30 minutes and then drying them. The mass ratio of aramid fibers to the silane coupling agent is 1:9-11. The immersion is carried out under shaking conditions. Specifically, the silane coupling agent is KH570. By modifying the aramid fibers with the silane coupling agent, the compatibility of the aramid fibers with biodegradable cellulose and polylactic acid is improved, fully utilizing the reinforcing effect of the aramid fibers.

[0035] The raw materials for preparing the biodegradable cooling and heat-insulating porous material of this invention include functional particles; the functional particles comprise a polymer, alumina, ceramic microspheres, ceramic fibers, diatomaceous earth, and white oil in a mass ratio of (10-15):(3-5):(3-5):(3-5):(3-5):(0.1-0.5). The functional particles are prepared by compounding the polymer and white oil into a heat-insulating material. The white oil has a lubricating effect, allowing for smooth granulation during twin-screw extrusion. This avoids potential damage to the functional particles during shearing when in contact with the screw, thus ensuring performance. This method satisfies the environmental requirements for biodegradability while also exhibiting excellent comprehensive performance.

[0036] The particle size of the alumina, ceramic microspheres, ceramic fibers, and diatomaceous earth in the functional particles is preferably within 10 μm. The composite functional particles of alumina, ceramic microspheres, ceramic fibers, and diatomaceous earth possess low density, low thermal conductivity, and heat insulation properties. After polymer coating and bonding, they form heat-insulating particles. These particles, along with biodegradable cellulose, polylactic acid, and modified aramid fibers, are used to prepare porous materials, resulting in porous materials with excellent heat insulation performance and thermal stability. Preferably, the functional particles are obtained by uniformly mixing the polymer, alumina, ceramic microspheres, ceramic fibers, diatomaceous earth, and white oil, followed by melt extrusion granulation using a screw extruder, yielding 50-100 mesh particles.

[0037] In a specific embodiment of the present invention, the functional particles comprise polyethylene, alumina, ceramic microspheres, ceramic fibers, diatomaceous earth, and white oil in a mass ratio of 10:3:5:3:3:0.1.

[0038] Or it may include polyurethane, alumina, ceramic microspheres, ceramic fibers, diatomaceous earth and white oil in a mass ratio of 13:4:4.5:4:4:0.35;

[0039] Or it may include polylactic acid, alumina, ceramic microspheres, ceramic fibers, diatomaceous earth and white oil in a mass ratio of 15:5:3:5:5:0.5.

[0040] In a specific embodiment of the present invention, the biodegradable cooling and heat-insulating porous material, by weight, comprises the following components: 86 parts chitosan nanofibers, 42 parts polylactic acid micropowder, 4 parts silane coupling agent modified aramid fiber, 6.3 parts functional particles, 58.8 parts sodium chloride, and 19.6 parts polyethylene oxide;

[0041] Or the biodegradable cooling and heat-insulating porous material, by weight, comprises the following components: 82 parts chitosan nanofibers, 35 parts polylactic acid micro powder, 3 parts silane coupling agent modified aramid fiber, 4 parts functional particles, 46 parts sodium chloride and 23 parts polyethylene oxide.

[0042] Or the biodegradable cooling and heat insulation porous material, by weight, comprises the following components: 84 parts chitosan nanofibers, 40 parts polylactic acid micro powder, 3 parts silane coupling agent modified aramid fiber, 5 parts functional particles, 56 parts sodium chloride and 25 parts polyethylene oxide.

[0043] Or the biodegradable cooling and heat-insulating porous material, by weight, comprises the following components: 85 parts chitosan nanofibers, 41 parts polylactic acid micro powder, 5 parts silane coupling agent modified aramid fiber, 6 parts functional particles, 62 parts sodium chloride and 21 parts polyethylene oxide.

[0044] Or the biodegradable cooling and heat-insulating porous material, by weight, comprises the following components: 83 parts chitosan nanofibers, 43 parts polylactic acid micro powder, 4 parts silane coupling agent modified aramid fiber, 7 parts functional particles, 65 parts sodium chloride and 21 parts polyethylene oxide.

[0045] The biodegradable cooling and heat-insulating porous material, by weight, comprises the following components: 88 parts chitosan nanofibers, 45 parts polylactic acid micropowder, 5 parts silane coupling agent modified aramid fiber, 8 parts functional particles, 72 parts sodium chloride, and 18 parts polyethylene oxide.

[0046] This invention provides a method for preparing the biodegradable cooling and heat-insulating porous material described in the above technical solution, comprising the following steps:

[0047] A premix is ​​prepared by mixing biodegradable cellulose, polylactic acid, silane coupling agent-modified aramid fiber, pore-forming agent, and functional particles.

[0048] The premixed material is melt-extruded to obtain a biodegradable cooling and heat-insulating porous material.

[0049] In this invention, the extrusion process uses a twin-screw extruder with a screw length-to-diameter ratio of 40:1; the extrusion vacuum is greater than -0.6 MPa; the extrusion head temperature is 180–220°C, the mid-section temperature is 200–220°C, and the die head temperature is 190–210°C. The particle size of the biodegradable cooling and heat-insulating porous material obtained by melt extrusion is 50–100 mesh.

[0050] The present invention also provides a tobacco filter rod, comprising the biodegradable cooling and heat-insulating porous material described in the above technical solution.

[0051] The tobacco filter rod described in this invention has a length of 120 mm and a circumference of 22.4 mm. This invention utilizes a biodegradable, cooling, and heat-insulating porous material to ensure its draw resistance meets specified requirements (2260–2840 Pa). The filter rod exhibits excellent filtration performance, with the main harmful substances in cigarettes (total particulate matter, nicotine, tar, etc.) meeting standard requirements. Furthermore, the filter rod demonstrates good biodegradability, and the filter tip possesses excellent cooling and heat insulation properties.

[0052] To further illustrate the present invention, the following detailed description, in conjunction with embodiments, provides a biodegradable cooling and heat-insulating porous material, its preparation method, and its applications. However, these descriptions should not be construed as limiting the scope of protection of the present invention.

[0053] Preliminary example

[0054] Preparation of cooling and heat-insulating functional particles:

[0055] According to the formula in Table 1, the polymer, alumina, ceramic microspheres, ceramic fiber, diatomaceous earth and white oil are mixed evenly, and then the mixture is melt-extruded and granulated by screw extruder to obtain 50-100 mesh particles.

[0056] Table 1 Functional Particle Formulation Components

[0057] polymer Alumina ceramic microspheres ceramic fiber diatomite White oil Functional particle a 10 parts polyethylene 3 copies 5 copies 3 copies 3 copies 0.1 copies Functional particle b 13 parts polyurethane 4 copies 4.5 copies 4 copies 4 copies 0.35 copies Functional particles c 15 Polylactic acid 5 copies 3 copies 5 copies 5 copies 0.5 copies Functional Particle A 13 parts polyurethane 4 copies 4.5 copies 4 copies 4 copies -- Functional Particle B -- 4 copies 4.5 copies 4 copies 4 copies 0.35 copies

[0058] Modified aramid fibers were prepared by the following method: aramid nanofibers and KH570 were weighed at a weight ratio of 1:10. The aramid fibers were added to a silane coupling agent solution and soaked for 25 minutes under shaking conditions. Then, the fibers were dried in an oven to obtain modified aramid fibers.

[0059] Example 1

[0060] A method for preparing a biodegradable cooling and heat-insulating porous material, the specific steps of which are as follows:

[0061] (1) Weigh the following raw material components: 86 parts chitosan nanofibers, 42 parts polylactic acid micro powder, 4 parts modified aramid fiber, 6.3 parts functional particles b, 58.8 parts sodium chloride with a particle size of 100-200μm, and 19.6 parts polyethylene oxide;

[0062] (2) The biodegradable cellulose, polylactic acid, modified aramid fiber, functional particles from the preparatory example, sodium chloride as a pore-forming agent, and polyethylene glycol as a pore-connecting agent are mixed evenly to form a premix.

[0063] (3) Add the premixed material to the twin-screw extruder, control the screw length-to-diameter ratio of the twin-screw extruder to be 40:1, the vacuum degree to be greater than -0.65MPa, the front section temperature to be 195℃, the middle section temperature to be 210℃, the die head extrusion temperature to be 200℃, and the screw speed to be 30r / min. The material is sheared and melted, drawn, cooled and dried in the twin-screw extruder to prepare a rod-shaped material. Then, it is immersed in warm water and soaked for 24 hours to obtain a biodegradable cooling and heat insulation porous material.

[0064] Examples 2-6

[0065] The preparation process is the same as in Example 1, and the specific formulation components are shown in Table 2:

[0066] Table 2. Raw material components and dosages for Examples 1-6

[0067]

[0068] In this invention, the porous materials prepared in Examples 1 to 6 are used to prepare tobacco filter rods. The porous materials are made into cigarette filter rods of the corresponding specifications (120 mm in length and 22.4 mm in circumference) using a filter rod forming machine. The draw resistance is tested, and the main indicators are tested according to GB5606-2005 "Cigarettes" standard (at least 8 rods are prepared for each group of samples, and the average value is taken).

[0069] Biodegradation testing shall be performed in accordance with the test method of ISO 14855.

[0070] The temperature of the smoke during the inhalation was measured, and the temperatures of the smoke during the first, fifth, and tenth inhalations were recorded.

[0071] The experimental results are shown in Table 3:

[0072] Table 3. Test results of the indicators of tobacco filter rods prepared from porous materials in Examples 1-6.

[0073]

[0074]

[0075] As shown in Table 3, the suction resistance of the filter rods obtained in the examples all meet the specified requirements (2260~2840Pa), the filter rods have good filtration performance, the main harmful substances in cigarettes (total particulate matter, nicotine, tar, etc.) all meet the standard requirements, and the filter rods have good biodegradability and the filter tips have good cooling and heat insulation properties.

[0076] Comparative Example 1

[0077] Without the addition of aramid fibers, everything else is the same as in Example 1.

[0078] Test results show that the extruded material is brittle, has poor toughness and mechanical properties, and cannot be processed into shapes.

[0079] Comparative Example 2

[0080] Unmodified ordinary aramid fibers were added, and everything else was the same as in Example 1.

[0081] Test results show that the material is tough and the absorption resistance value of 2523Pa is within a suitable range, but the surface appearance of the sample is poor and rough during extrusion.

[0082] Comparative Example 3

[0083] No functional particles were added; otherwise, it was the same as in Example 1.

[0084] Test results show that the material has excellent mechanical properties and a resistance value of 2633 Pa, which is within a suitable range. However, its cooling and heat insulation properties are poor, with the first flue gas temperature at 45℃, the fifth flue gas temperature at 55℃, and the tenth flue gas temperature at 58℃.

[0085] Comparative Example 4

[0086] Functional particle A was used, and everything else was the same as in Example 1.

[0087] Test results show that the mechanical properties of the extruded material deteriorate, the porous material is difficult to process and form, the suction resistance increases, and the cooling and heat insulation effect is not as good as the example. The temperature of the first flue gas is 35℃, the temperature of the fifth flue gas is 39℃, and the temperature of the tenth flue gas is 44℃.

[0088] Comparative Example 5

[0089] Functional particle B was used, and everything else was the same as in Example 1.

[0090] Test results show that the mechanical properties of the extruded material deteriorate, the particles are difficult to form, they easily detach from the porous material, the suction resistance increases, and the cooling and heat insulation effects are poor. The temperature of the first flue gas is 39℃, the temperature of the fifth flue gas is 43℃, and the temperature of the tenth flue gas is 47℃.

[0091] As can be seen from the above embodiments, the present invention provides a biodegradable cooling and heat-insulating porous material. The raw materials, by weight, include the following components: 82-88 parts biodegradable cellulose, 35-45 parts polylactic acid, 3-5 parts silane coupling agent modified aramid fiber, 4-8 parts functional particles, and a pore-forming agent; the pore-forming agent is selected from water-soluble salts; the mass ratio of the pore-forming agent to polylactic acid is 1.3-1.6:1; the functional particles include a polymer, alumina, ceramic microspheres, ceramic fibers, diatomaceous earth, and white oil in a mass ratio of (10-15):(3-5):(3-5):(3-5):(3-5):(0.1-0.5). This invention uses polylactic acid and biodegradable cellulose as the main body of a porous structure, and combines a certain amount of modified aramid fiber and cooling and heat-insulating functional particles. Biodegradable cellulose has good mechanical properties and flame-retardant and high-temperature resistance properties, which can improve the high-temperature and high-humidity mechanical properties of porous composite materials and is beneficial to the stability of porous structures. In particular, the addition of functional particles composed of specific raw materials has a significant cooling effect, while ensuring smooth suction.

[0092] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A degradable temperature-reducing and heat-insulating porous material, raw materials for preparation of the degradable temperature-reducing and heat-insulating porous material comprising, by weight, the following components: 82-88 parts of degradable cellulose, 35-45 parts of polylactic acid, 3-5 parts of aramid fiber modified by silane coupling agent, 4-8 parts of functional particles, and pore-forming agent; the degradable cellulose being chitosan nanofiber; the pore-forming agent being selected from water-soluble salt; a mass ratio of the pore-forming agent to the polylactic acid being 1.3-1.6:1; the functional particles comprising polymer, alumina, ceramic microbead, ceramic fiber, diatomite, and white oil at a mass ratio of (10-15):(3-5):(3-5):(3-5):(3-5):(0.1-0.5). The polymer is selected from one or more of polyethylene, polyurethane, polylactic acid, and polyethylene oxide. The aramid fiber modified by silane coupling agent is prepared by placing aramid fiber in silane coupling agent, soaking for 10-30 min, and drying. A mass ratio of the aramid fiber to the silane coupling agent is 1:9-11.

2. The degradable temperature-reducing insulating porous material according to claim 1, characterized in that, A particle size of the pore-forming agent is 50-400 μm.

3. The degradable temperature-reducing insulating porous material according to claim 1, wherein, The water-soluble salt is selected from one or more of sodium chloride, sodium citrate, and calcium carbonate. The raw materials for preparation further comprise pore-communicating agent; the pore-communicating agent being selected from one or more of polyacrylamide, polyethylene glycol, and polyethylene oxide.

4. The degradable temperature-reducing insulating porous material according to claim 1, wherein, The functional particles comprise polyethylene, alumina, ceramic microbead, ceramic fiber, diatomite, and white oil at a mass ratio of 10:3:5:3:3:0.

1.

5. The degradable temperature-reducing insulating porous material according to claim 1, wherein, Or comprise polyurethane, alumina, ceramic microbead, ceramic fiber, diatomite, and white oil at a mass ratio of 13:4:4.5:4:4:0.

35.

6. The degradable temperature-reducing insulating porous material of claim 1, wherein, Or comprise polylactic acid, alumina, ceramic microbead, ceramic fiber, diatomite, and white oil at a mass ratio of 15:5:3:5:5:0.

5.

7. The degradable temperature-reducing insulating porous material according to claim 2, wherein, 8.A method for preparing the degradable temperature-reducing and heat-insulating porous material according to any one of claims 1-7, comprising the following steps: mixing the degradable cellulose, the polylactic acid, the aramid fiber modified by silane coupling agent, the pore-forming agent, and the functional particles to obtain premix; and melt-extruding the premix to obtain the degradable temperature-reducing and heat-insulating porous material. The screw length-diameter ratio of the twin-screw extruder used in the extrusion is 40:

1. The vacuum degree of the extrusion is greater than -0.6 MPa. The temperature of the front section of the extrusion is 180-220 ℃, the temperature of the middle section is 200-220 ℃, and the temperature of the die head is 190-210 ℃. 10.A tobacco filter rod comprising the degradable temperature-reducing and heat-insulating porous material according to any one of claims 1-7. ​ 9. The production method according to claim 8, characterized by, ​ ​ ​ ​

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