Degradable filter element and preparation method thereof

Abstract

The invention relates to a degradable filter element and a preparation method thereof, and belongs to the technical field of PLA filter elements. The degradable filter element is arranged between an atomizing element shell and a metal heating wire, a plurality of capillary holes are formed in the degradable filter element and used for being filled with tobacco tar, and the degradable filter element is prepared from a degradable composite material through melt spinning. The degradable composite material comprises the following components: polylactic acid and modified silicon dioxide, wherein the modified silicon dioxide is prepared by taking nano silicon dioxide, a silane coupling agent, ferulic acid, amino acid and copper chloride as raw materials, the silicon dioxide is organically modified, so that the dispersity of the silicon dioxide in a polylactic acid system is improved, the interface binding force of the silicon dioxide is improved, and the mechanical property of a polylactic acid material is improved; various antibacterial components are introduced, so that the antibacterial property of the polylactic acid material can be effectively improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of PLA filters, and relates to a degradable filter element and a preparation method thereof. Background Art

[0002] With the continuous attention to environmental protection issues globally and the gradual depletion of oil resources, the development and application of biodegradable polymer materials have developed rapidly. Polylactic acid, usually abbreviated as PLA, is a polyester polymer prepared by a polymerization reaction using lactic acid as the main raw material. As a new type of biodegradable material, polylactic acid can be completely degraded under the action of microorganisms in nature after use, and finally converted into carbon dioxide and water, thus avoiding environmental pollution. However, polylactic acid materials also have certain limitations. It is a material with relatively high brittleness. Specifically, the elongation at break and impact strength of polylactic acid are relatively low, which means that it is prone to brittle fracture when subjected to external forces, thus limiting its wide use in some application fields.

[0003] The patent document with the publication number CN106147173B discloses a preparation method of a high-toughness polylactic acid wood-plastic composite material: Preparation of plant fibers: Take coconut fibers, sugarcane bagasse, Manchurian ash wood powder, and rice husk powder and mix them evenly; Enzyme modification of plant fibers: Perform enzyme modification on the mixed plant fibers; After modification, rinse them clean with water and dry them at 60 °C; Raw material blending: Prepare the dried raw materials according to the following weight parts: 42-60 parts of modified plant fibers, 100-120 parts of polylactic acid, and 0.8 part of nano calcium carbonate; After completely melting the weighed polylactic acid pellets on an open mill, uniformly add the modified plant fibers, and after mixing evenly, add all other raw materials, adjust the rotation speed to 30 r / min, and then turn the materials and blend them for 5-6 min to make the raw materials fully mixed evenly; Pre-press; Hot press molding. This patent document points out that by adding modified plant fibers and nano calcium carbonate to polylactic acid, the toughness of polylactic acid can be enhanced. However, there are certain deficiencies in the dispersion uniformity of nano calcium carbonate in the polylactic acid system. Summary of the Invention

[0004] The purpose of the present invention is to provide a degradable filter element and a preparation method thereof. The present invention increases the dispersibility of silica in the polylactic acid system through organic modification of silica, improves the interfacial bonding force, improves the mechanical properties of the polylactic acid material, and introduces a variety of antibacterial components, which can effectively improve the antibacterial property of the polylactic acid material.

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

[0006] A degradable filter element is provided between an atomizing core housing and a metal heating wire. The degradable filter element is provided with a plurality of capillary pores for filling e-liquid. The degradable filter element is prepared by melt spinning of a degradable composite material. The degradable composite material comprises the following components in parts by weight:

[0007] 120-140 parts of polylactic acid and 6-8 parts of modified silica;

[0008] The preparation of the modified silica comprises the following steps:

[0009] Step 1: Mix nano-silica and an ethanol aqueous solution, perform ultrasonic treatment, add a silane coupling agent, heat and stir, purify, and then perform vacuum drying to obtain prefabricated particles;

[0010] Step 2: Mix the prefabricated particles and absolute ethanol, add ferulic acid and vinyl salicylaldehyde, stir and mix, add an initiator, perform heat treatment, purify, and then perform vacuum drying to obtain an intermediate;

[0011] Step 3: Mix the intermediate and absolute ethanol, stir and mix, add an amino acid solution, heat and stir, perform centrifugal purification and then vacuum drying, then soak in a copper chloride solution and let stand, filter, and dry to constant weight to obtain the product.

[0012] As a preferred technical solution of the present invention, the polylactic acid used in the present invention is prepared from corn or starch as a raw material. As a matrix material, it exhibits excellent biodegradable properties. By introducing organically modified nano-silica, the melt viscosity of polylactic acid during melt processing can be effectively reduced without affecting the glass transition temperature of the material, and the mechanical properties of the material can be effectively improved. Different from the traditional addition of plasticizers that causes a decrease in the glass transition temperature and weakening of the mechanical properties of the material, the present invention effectively improves the thermal stability of polylactic acid and solves the problem of material decomposition caused by an increase in melt fluidity at high temperatures.

[0013] As a preferred technical solution of the present invention, during the production of the degradable filter element by melt spinning, by controlling the spinning speed and the stretching speed, short fibers of different lengths can be obtained. A fiber web is formed by the short fibers, and then it is reinforced to make a non-woven fabric. After the spinning of the non-woven fabric is completed, a non-woven fabric is obtained. After heating and melting the non-woven fabric, it enters a filter element mold for shaping treatment. The shaping treatment exposes the non-woven fabric to high temperatures to fix its shape and size. The stretching and shaping treatments can increase the strength and elasticity of the fibers and improve the quality of the filter element.

[0014] As a preferred technical solution of the present invention, in Step 1, the ultrasonic treatment is ultrasonic treatment at a frequency of 100-120W for 40-50min.

[0015] As a preferred technical solution of the present invention, in Step 1, the heating and stirring is carried out at a temperature of 50 - 60°C and a rotation speed of 200 - 360 r / min for 5 - 6 h.

[0016] As a preferred technical solution of the present invention, in Step 1, the purification is carried out by washing three times with absolute ethanol after filtration.

[0017] As a preferred technical solution of the present invention, in Step 1, the vacuum drying is carried out in a drying oven at a temperature of 80 - 90°C for 10 - 12 h under vacuum.

[0018] As a preferred technical solution of the present invention, in Step 1, the mass ratio of the nano-silica, ethanol aqueous solution and silane coupling agent is 1.0 - 1.2 : 6.0 - 7.0 : 1.2 - 1.5.

[0019] As a preferred technical solution of the present invention, in Step 1, the mass fraction of the ethanol aqueous solution is 92 - 96%; the silane coupling agent is silane coupling agent A - 171; the diameter of the nano-silica is 20 nm.

[0020] As a preferred technical solution of the present invention, in Step 2, the stirring and mixing time is 30 - 45 min.

[0021] As a preferred technical solution of the present invention, in Step 2, the heating treatment is carried out by constant temperature stirring at a temperature of 65 - 75°C for 4 - 5 h.

[0022] As a preferred technical solution of the present invention, in Step 2, the purification is carried out by washing three times with absolute ethanol after filtration.

[0023] As a preferred technical solution of the present invention, in Step 2, the vacuum drying is carried out in a drying oven at a temperature of 80 - 90°C until constant weight under vacuum.

[0024] As a preferred technical solution of the present invention, in Step 2, the mass ratio of the prefabricated particles, absolute ethanol, ferulic acid, vinyl salicylaldehyde and initiator is 20 - 22 : 25 - 30 : 4.0 - 5.2 : 2.4 - 3.0 : 0.12 - 0.14; the initiator is azobisisobutyronitrile.

[0025] As a preferred technical solution of the present invention, in Step 3, the stirring and mixing is carried out at a rotation speed of 200 - 400 r / min for 20 - 30 min.

[0026] As a preferred technical solution of the present invention, in Step 3, the heating and stirring is carried out by stirring at a temperature of 60 - 70°C for 5 - 6 h.

[0027] As a preferred technical solution of the present invention, in step three, the centrifugal purification is to wash three times with absolute ethanol after removing the supernatant.

[0028] As a preferred technical solution of the present invention, in step three, the vacuum drying is to dry to constant weight; the standing time is 20 - 24 h.

[0029] As a preferred technical solution of the present invention, in step three, the mass ratio of the intermediate, absolute ethanol, amino acid solution and copper chloride solution is 16 - 20:25 - 30:6.2 - 7.4:5.0 - 5.8.

[0030] As a preferred technical solution of the present invention, in step three, the amino acid solution is prepared by mixing cysteine and deionized water in a mass ratio of 1:5; the copper chloride solution is prepared by mixing copper chloride and deionized water in a dosage ratio of 2 - 3 g:100 - 120 mL.

[0031] The present invention discloses that the preparation method of the degradable composite material includes the following steps: placing polylactic acid and modified silica in an extruder and performing melt extrusion at a temperature of 180 - 190 °C, cooling, and pelletizing to obtain the degradable composite material.

[0032] Advantages of the present invention:

[0033] The present invention uses nano - silica, silane coupling agent, ferulic acid, amino acid and copper chloride as raw materials to prepare modified silica. By performing organic modification, the dispersion of silica in the polylactic acid system is increased, the interfacial bonding force is improved. While improving the mechanical properties of the polylactic acid material, a variety of antibacterial components are introduced, which can effectively improve the antibacterial performance of the polylactic acid material. Specific embodiments

[0034] To further elaborate on the technical means and effects adopted by the present invention to achieve the predetermined invention purpose, the following examples are used to detail the specific embodiments, structures, features and their effects according to the present invention.

[0035] A degradable filter element is arranged between the atomizing core housing and the metal heating wire. A plurality of capillary pores are opened on the degradable filter element, and the plurality of capillary pores are used for filling e - liquid. The degradable filter element is prepared by melt - spinning from a degradable composite material.

[0036] Example 1

[0037] The degradable composite material includes the following components by weight:

[0038] 120 parts of polylactic acid and 6 parts of modified silica;

[0039] The preparation method of the degradable composite material comprises the following steps: placing polylactic acid and modified silica in an extruder, performing melt extrusion at a temperature of 180°C, cooling, and pelletizing to obtain the degradable composite material.

[0040] The preparation of the modified silica comprises the following steps:

[0041] Step 1: Mix nano-silica and an ethanol aqueous solution, perform ultrasonic treatment at a frequency of 100W for 40 min, add a silane coupling agent, stir at a temperature of 50°C and a rotation speed of 200 r / min for 5 h, filter, wash three times with absolute ethanol, and vacuum dry in a drying oven at a temperature of 80°C for 10 h to obtain prefabricated particles; the mass ratio of the nano-silica, the ethanol aqueous solution, and the silane coupling agent is 1.0:6.0:1.2; the mass fraction of the ethanol aqueous solution is 92%; the silane coupling agent is silane coupling agent A-171;

[0042] Step 2: Mix the prefabricated particles and absolute ethanol, add ferulic acid and vinyl salicylaldehyde, stir and mix for 30 min, add an initiator, and stir at a constant temperature of 65°C for 4 h, filter, wash three times with absolute ethanol, and vacuum dry in a drying oven at a temperature of 80°C to constant weight to obtain an intermediate; the mass ratio of the prefabricated particles, absolute ethanol, ferulic acid, vinyl salicylaldehyde, and the initiator is 20:25:4.0:2.4:0.12; the initiator is azobisisobutyronitrile;

[0043] Step 3: Stir the intermediate and absolute ethanol at a rotation speed of 200 r / min for 20 min, add an amino acid solution, stir at a temperature of 60°C for 5 h, centrifuge to remove the supernatant, wash three times with absolute ethanol, vacuum dry at 80°C to constant weight, then soak in a copper chloride solution and let stand for 20 h, filter, and dry to constant weight to obtain the product; wherein, the mass ratio of the intermediate, absolute ethanol, the amino acid solution, and the copper chloride solution is 16:25:6.2:5.0; the amino acid solution is composed of cysteine and deionized water mixed in a mass ratio of 1:5; the copper chloride solution is composed of copper chloride and deionized water mixed in a dosage ratio of 2 g:100 mL.

[0044] Example 2

[0045] The degradable composite material comprises the following components by weight:

[0046] 125 parts of polylactic acid and 6.5 parts of modified silica;

[0047] The preparation method of the degradable composite material comprises the following steps: placing polylactic acid and modified silica in an extruder, performing melt extrusion at a temperature of 182°C, cooling, and pelletizing to obtain the degradable composite material.

[0048] The preparation of the modified silica includes the following steps:

[0049] Step 1: Mix nano-silica and an ethanol aqueous solution, then ultrasonicate at a frequency of 105 W for 42 min. Add a silane coupling agent and stir at a temperature of 52 °C and a rotation speed of 240 r / min for 5 h. After filtration, wash three times with absolute ethanol and vacuum dry in an oven at 82 °C for 10 h to obtain prefabricated particles; the mass ratio of the nano-silica, ethanol aqueous solution, and silane coupling agent is 1.05:6.2:1.3; the mass fraction of the ethanol aqueous solution is 93%; the silane coupling agent is silane coupling agent A-171;

[0050] Step 2: Mix the prefabricated particles and absolute ethanol, then add ferulic acid and vinyl salicylaldehyde and stir and mix for 35 min. Add an initiator and stir at a constant temperature of 68 °C for 4.2 h. After filtration, wash three times with absolute ethanol and vacuum dry in an oven at 82 °C to constant weight to obtain an intermediate; the mass ratio of the prefabricated particles, absolute ethanol, ferulic acid, vinyl salicylaldehyde, and initiator is 20.5:26:4.3:2.6:0.125; the initiator is azobisisobutyronitrile;

[0051] Step 3: Stir the intermediate and absolute ethanol at a rotation speed of 250 r / min for 25 min, then add an amino acid solution and stir at a temperature of 62 °C for 5.5 h. After centrifuging to remove the supernatant, wash three times with absolute ethanol and vacuum dry at 80 °C to constant weight, then soak in a copper chloride solution and let stand for 20 h, filter and dry to constant weight to obtain the product; among them, the mass ratio of the intermediate, absolute ethanol, amino acid solution, and copper chloride solution is 17:26:6.5:5.2; the amino acid solution is composed of cysteine and deionized water mixed in a mass ratio of 1:5; the copper chloride solution is composed of copper chloride and deionized water mixed in a dosage ratio of 2.2 g:105 mL.

[0052] Example 3

[0053] The degradable composite material includes the following components by weight:

[0054] 130 parts of polylactic acid and 7 parts of modified silica;

[0055] The preparation method of the degradable composite material includes the following steps: Place polylactic acid and modified silica in an extruder and perform melt extrusion at a temperature of 185 °C, cool, and pelletize to obtain the degradable composite material.

[0056] The preparation of the modified silica includes the following steps:

[0057] Step 1: Mix nano-silica and ethanol aqueous solution, then ultrasonic at a frequency of 110W for 45 min. Add silane coupling agent and stir at a temperature of 55°C and a rotation speed of 280 r / min for 5.5 h. After filtration, wash three times with absolute ethanol, and vacuum dry in an oven at 85°C for 11 h to obtain prefabricated particles. The mass ratio of the nano-silica, ethanol aqueous solution and silane coupling agent is 1.1:6.5:1.35; the mass fraction of the ethanol aqueous solution is 94%; the silane coupling agent is silane coupling agent A-171;

[0058] Step 2: Mix the prefabricated particles and absolute ethanol, then add ferulic acid and vinyl salicylaldehyde and stir and mix for 38 min. Add initiator and stir at a constant temperature of 70°C for 4.5 h. After filtration, wash three times with absolute ethanol, and vacuum dry in an oven at 85°C to constant weight to obtain an intermediate. The mass ratio of the prefabricated particles, absolute ethanol, ferulic acid, vinyl salicylaldehyde and initiator is 21:28:4.6:2.7:0.13; the initiator is azobisisobutyronitrile;

[0059] Step 3: Stir the intermediate and absolute ethanol at a rotation speed of 300 r / min for 25 min, then add amino acid solution and stir at a temperature of 65°C for 5.5 h. Centrifuge to remove the supernatant, wash three times with absolute ethanol, vacuum dry at 80°C to constant weight, then soak in copper chloride solution and let stand for 22 h, filter and dry to constant weight to obtain the product. Among them, the mass ratio of the intermediate, absolute ethanol, amino acid solution and copper chloride solution is 18:28:6.8:5.4; the amino acid solution is composed of cysteine and deionized water mixed according to a mass ratio of 1:5; the copper chloride solution is composed of copper chloride and deionized water mixed according to a dosage ratio of 2.5 g:110 mL.

[0060] Example 4

[0061] The degradable composite material comprises the following components by weight:

[0062] 135 parts of polylactic acid and 7.5 parts of modified silica;

[0063] The preparation method of the degradable composite material comprises the following steps: Place polylactic acid and modified silica in an extruder and carry out melt extrusion at a temperature of 188°C, cool, and pelletize to obtain the degradable composite material.

[0064] The preparation of the modified silica comprises the following steps:

[0065] Step 1: Mix nano-silica and ethanol aqueous solution, then ultrasonicate for 48 min at a frequency of 115 W. Add silane coupling agent and stir at 58 °C and 320 r / min for 5.8 h. After filtration, wash three times with absolute ethanol and vacuum dry in an oven at 88 °C for 11.5 h to obtain prefabricated particles. The mass ratio of nano-silica, ethanol aqueous solution and silane coupling agent is 1.15:6.8:1.42. The mass fraction of the ethanol aqueous solution is 95%. The silane coupling agent is silane coupling agent A-171.

[0066] Step 2: Mix prefabricated particles and absolute ethanol, then add ferulic acid and vinyl salicylaldehyde and stir and mix for 40 min. Add initiator and stir at a constant temperature of 72 °C for 4.8 h. After filtration, wash three times with absolute ethanol and vacuum dry in an oven at 88 °C to constant weight to obtain an intermediate. The mass ratio of prefabricated particles, absolute ethanol, ferulic acid, vinyl salicylaldehyde and initiator is 21.5:29:4.9:2.8:0.135. The initiator is azobisisobutyronitrile.

[0067] Step 3: Stir the intermediate and absolute ethanol at 350 r / min for 28 min, then add amino acid solution and stir at 68 °C for 5.8 h. After centrifuging to remove the supernatant, wash three times with absolute ethanol and vacuum dry to constant weight at 80 °C. Then soak in copper chloride solution and let stand for 23 h, filter and dry to constant weight to obtain the product. Among them, the mass ratio of the intermediate, absolute ethanol, amino acid solution and copper chloride solution is 19:29:7.1:5.6. The amino acid solution is composed of cysteine and deionized water mixed according to a mass ratio of 1:5. The copper chloride solution is composed of copper chloride and deionized water mixed according to a dosage ratio of 2.8 g:115 mL.

[0068] Example 5

[0069] The degradable composite material comprises the following components by weight:

[0070] The degradable composite material comprises the following components by weight:

[0071] 140 parts of polylactic acid and 8 parts of modified silica;

[0072] The preparation method of the degradable composite material comprises the following steps: Place polylactic acid and modified silica in an extruder and carry out melt extrusion at 190 °C, cool, and pelletize to obtain the degradable composite material.

[0073] The preparation of the modified silica comprises the following steps:

[0074] Step 1: Mix nano-silica and ethanol aqueous solution, then ultrasonic for 50 min at a frequency of 120 W. Add silane coupling agent and stir at 60 °C and 360 r / min for 6 h. After filtration, wash three times with absolute ethanol and vacuum dry in an oven at 90 °C for 12 h to obtain prefabricated particles. The mass ratio of nano-silica, ethanol aqueous solution and silane coupling agent is 1.2:7.0:1.5. The mass fraction of the ethanol aqueous solution is 96%. The silane coupling agent is silane coupling agent A-171.

[0075] Step 2: Mix prefabricated particles and absolute ethanol, then add ferulic acid and vinyl salicylaldehyde and stir for 45 min. Add initiator and stir at a constant temperature of 75 °C for 5 h. After filtration, wash three times with absolute ethanol and vacuum dry in an oven at 90 °C until constant weight to obtain an intermediate. The mass ratio of prefabricated particles, absolute ethanol, ferulic acid, vinyl salicylaldehyde and initiator is 22:30:5.2:3.0:0.14. The initiator is azobisisobutyronitrile.

[0076] Step 3: Stir the intermediate and absolute ethanol at 400 r / min for 30 min, then add amino acid solution and stir at 70 °C for 6 h. After centrifuging to remove the supernatant, wash three times with absolute ethanol and vacuum dry at 80 °C until constant weight. Then soak in copper chloride solution and let stand for 24 h, filter and dry to constant weight to obtain the product. Among them, the mass ratio of the intermediate, absolute ethanol, amino acid solution and copper chloride solution is 20:30:7.4:5.8. The amino acid solution is composed of cysteine and deionized water mixed according to a mass ratio of 1:5. The copper chloride solution is composed of copper chloride and deionized water mixed according to a dosage ratio of 3 g:120 mL.

[0077] Comparative Example 1

[0078] Compared with Example 4, the difference in Comparative Example 1 is that the silane coupling agent is not used in Step 1, and the other components, preparation steps and parameters are the same.

[0079] Comparative Example 2

[0080] Compared with Example 4, the difference in Comparative Example 2 is that styrene is used instead of ferulic acid in Step 2, and the other components, preparation steps and parameters are the same.

[0081] Comparative Example 3

[0082] Compared with Example 4, the difference in Comparative Example 3 is that ferulic acid is not used in Step 2, and the other components, preparation steps and parameters are the same.

[0083] Comparative Example 4

[0084] Compared with Example 4, the difference in Comparative Example 4 is that vinyl salicylaldehyde is not used in Step 2, and the other components, preparation steps, and parameters are the same.

[0085] Comparative Example 5

[0086] Compared with Example 4, the difference in Comparative Example 5 is that glutamic acid is used instead of cysteine in Step 3, and the other components, preparation steps, and parameters are the same.

[0087] Comparative Example 6

[0088] Compared with Example 4, the difference in Comparative Example 6 is that cysteine is not used in Step 3, and the other components, preparation steps, and parameters are the same.

[0089] Comparative Example 7

[0090] Compared with Example 4, the difference in Comparative Example 7 is that deionized water is used instead of copper chloride solution in Step 3, and the other components, preparation steps, and parameters are the same.

[0091] The antibacterial properties of the degradable composite materials prepared in Examples 1-5 and Comparative Examples 1-7 were tested respectively;

[0092] Antibacterial property test: According to GB / T31402-2015, the test results are shown in Table 1.

[0093] Table 1

[0094]

[0095]

[0096] As can be seen from the test results in Table 1, compared with Comparative Examples 1-7, the antibacterial properties of the degradable composite materials prepared in the present invention are significantly better than those of Comparative Examples 1-7.

[0097] The elongation at break of the degradable composite materials prepared in Examples 1-5 and Comparative Examples 1-7 was tested respectively;

[0098] Elongation at break test: According to GB / T528-2009, the test results are shown in Table 2;

[0099] Table 2

[0100]

[0101]

[0102] As can be seen from the test results in Table 2, compared with Comparative Examples 1-7, the elongation at break of the degradable composite materials prepared in the present invention is better than that of the composite materials prepared in Comparative Examples 1-7.

[0103] Comparing Examples 1 - 5 with Comparative Examples 1 - 7 and analyzing in combination with Tables 1 and 2, it can be seen that by introducing organically modified nano - sized silica particles, the present invention can effectively reduce the melt viscosity of polylactic acid during melt processing, while keeping the glass transition temperature of the material unchanged and not damaging the mechanical properties of the material. Nano - silica reacts with a silane coupling agent to introduce unsaturated carbon - carbon bonds, and then forms a copolymer with ferulic acid and vinyl salicylaldehyde through the unsaturated carbon - carbon bonds. The methoxy group of ferulic acid has a good binding force with polylactic acid, and the oxygen - containing functional groups of vinyl salicylaldehyde and cysteine can further increase the binding force with polylactic acid, realizing a stable connection between the inorganic silica - toughened material and the polylactic acid matrix material. The finally formed imine structure endows the polylactic acid material with better mechanical properties and further effectively improves the toughness of the polylactic acid material.

[0104] In the present invention, the antibacterial property of the polylactic acid material is improved by adding ferulic acid, vinyl salicylaldehyde, cysteine and copper chloride; specifically, the silane coupling agent, ferulic acid and vinyl salicylaldehyde copolymerize and combine, endowing the modified silica with more uniform dispersion in the polylactic acid system. While increasing its interfacial binding force, the formation of the copolymer can effectively improve the stability of ferulic acid, thereby improving the antibacterial property of the polylactic acid material. The finally formed Schiff base compound has better antibacterial properties, and the formed porous structure can combine with the introduction of thiol groups to effectively adsorb more copper chloride, further increasing its antibacterial property.

[0105] The above - mentioned are only the preferred embodiments of the present invention and do not impose any form of limitation on the present invention. Although the present invention has been disclosed above with preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make some changes or modifications to the above - disclosed technical content to obtain equivalent embodiments with equivalent changes within the scope of the technical solution of the present invention. However, as long as it does not deviate from the content of the technical solution of the present invention, any brief modification, equivalent change and modification made to the above embodiments based on the technical essence of the present invention still fall within the scope of the technical solution of the present invention.

Claims

1. A degradable filter element, the degradable filter element is arranged between the atomizer core shell and the metal heating wire, the degradable filter element is provided with a plurality of capillaries, the plurality of capillaries are used to fill the e-liquid, the degradable filter element is made of a degradable composite material by melt spinning, and is characterized in that: The degradable composite material comprises the following components in parts by weight: 120-140 parts of polylactic acid and 6-8 parts of modified silicon dioxide; Wherein, the preparation of the modified silicon dioxide comprises the following steps: Step 1: Mix nano-silica and ethanol aqueous solution and perform ultrasonic treatment, add silane coupling agent, heat and stir, purify and vacuum dry to obtain prefabricated particles; Step 2: After mixing the prefabricated particles with anhydrous ethanol, ferulic acid and vinyl salicylaldehyde are added and stirred, an initiator is added and heated, and after purification, vacuum drying is performed to obtain an intermediate; Step 3: After the intermediate and anhydrous ethanol are stirred and mixed, the amino acid solution is added, heated and stirred, centrifuged and purified, vacuum dried, then immersed in a copper chloride solution and allowed to stand, filtered and dried to constant weight to obtain.

2. A degradable filter element according to claim 1, characterized in that: In step one, the ultrasonic treatment is performed at a frequency of 100-120W for 40-50 minutes; the heating stirring is performed at a temperature of 50-60°C and a speed of 200-360r / min for 5-6 hours; the purification is performed by filtering and then washing three times with anhydrous ethanol; and the vacuum drying is performed in a drying oven at a temperature of 80-90°C for 10-12 hours.

3. A degradable filter element according to claim 1, characterized in that: In step 1, the mass ratio of the nano-silicon dioxide, the ethanol aqueous solution and the silane coupling agent is 1.0-1.2:6.0-7.0:1.2-1.

5.

4. A degradable filter element according to claim 1, characterized in that: In step 1, the mass fraction of the ethanol aqueous solution is 92-96%; the silane coupling agent is silane coupling agent A-171; and the diameter of the nano-silicon dioxide is 20 nm.

5. The degradable filter element according to claim 1, characterized in that: In step 2, the stirring and mixing time is 30-45 minutes; the heating treatment is constant temperature stirring at 65-75°C for 4-5 hours; the purification is washing three times with anhydrous ethanol after filtration; and the vacuum drying is vacuum drying in a drying oven at 80-90°C to constant weight.

6. The degradable filter element according to claim 1, characterized in that: In step 2, the mass ratio of the prefabricated particles, anhydrous ethanol, ferulic acid, vinyl salicylaldehyde and initiator is 20-22:25-30:4.0-5.2:2.4-3.0:0.12-0.14; the initiator is azobisisobutyronitrile.

7. The degradable filter element according to claim 1, characterized in that: In step three, the stirring and mixing is stirring at a speed of 200-400 r / min for 20-30 minutes; the heating and stirring is stirring at a temperature of 60-70°C for 5-6 hours; the centrifugal purification is washing three times with anhydrous ethanol after removing the supernatant; the vacuum drying is drying to constant weight; and the standing time is 20-24 hours.

8. The degradable filter element according to claim 1, characterized in that: In step three, the mass ratio of the intermediate, anhydrous ethanol, amino acid solution and cupric chloride solution is 16-20:25-30:6.2-7.4:5.0-5.

8.

9. The degradable filter element according to claim 1, characterized in that: In step three, the amino acid solution is prepared by mixing cysteine ​​and deionized water in a mass ratio of 1:5; the cupric chloride solution is prepared by mixing cupric chloride and deionized water in a dosage ratio of 2-3 g:100-120 mL.

10. A method for preparing a degradable filter element according to any one of claims 1 to 9, characterized in that: The preparation method comprises the following steps: placing polylactic acid and modified silicon dioxide in an extruder for melt extrusion at a temperature of 180-190° C., cooling, and pelletizing to obtain a degradable composite material.

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