SMMS non-woven fabric and preparation method thereof
By improving the dispersibility and compatibility of the spunbond and meltblown layers, and combining specific fillers and additives, the problem of decreased air permeability of SMMS nonwoven fabrics when strength is increased has been solved, achieving a balance between high strength and high air permeability, and improving production stability and aging resistance.
Patent Information
- Application Number
- CN202511321110.2
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-09-16
- Publication Date
- 2025-12-19
AI Technical Summary
In the current technology for preparing SMMS nonwoven fabrics, increasing the strength leads to decreased air permeability, poor production stability, and poor dispersion of filler components, which affects the overall stability of the nonwoven fabric.
By using specific reinforcing fillers and meltblown additives, improving the compatibility between the modified liquid and the polymer, and combining components such as amino silicone oil, spunbond and meltblown layers are prepared. Polylactic acid and polypropylene are compounded to balance flexibility and strength, and the interlayer bonding force is optimized by controlling hot rolling parameters.
It improves the strength and breathability of nonwoven fabrics, ensures production stability, and exhibits excellent resistance to light aging.
Smart Images
Figure SMS_1 
Figure SMS_2 
Figure SMS_3
Abstract
Description
Technical Field
[0001] This invention belongs to the field of nonwoven fabric technology, specifically relating to an SMMS nonwoven fabric and its preparation method. Background Technology
[0002] SMMS nonwoven fabric is a composite nonwoven fabric composed of a four-layer structure: spunbond-meltblown-meltblown-spunbond. The spunbond layer (S layer) is made from thermoplastic polymers such as polypropylene, which are spunbonded to form continuous filaments, giving the product excellent longitudinal and transverse tensile strength, tear resistance, and a soft touch. The meltblown layer (M layer) is made from polymer raw materials with a high melt index, which are melted at high temperature and stretched by high-speed airflow to form ultrafine fibers. With its small fiber diameter and large specific surface area, it achieves excellent liquid barrier properties, filtration performance, and hydrostatic pressure resistance. The synergistic use of the four layers gives SMMS nonwoven fabric excellent properties such as high strength, high filtration efficiency, and good breathability, making it an ideal material for making medical protective clothing, surgical gowns, sterilization drapes, high-end baby diapers, and the surface layer of feminine hygiene products.
[0003] In the current process of preparing SMMS nonwoven fabric, the spunbond layer and meltblown layer are usually made of polypropylene as the matrix component. The molecular structure of polypropylene determines that its fiber surface is smooth and has poor hydrophilicity. The fibers in the meltblown layer are only physically entangled and have no chemical bonding sites. When the air permeability is improved and the fiber density is reduced, the interlayer bonding force drops sharply. In addition, the thermal stability of polypropylene is limited, and the spunbond layer cannot be fully bonded by high-temperature hot rolling, so the room for improvement in strength is limited.
[0004] To improve the strength of SMMS nonwoven fabric, existing technologies usually involve increasing the hot rolling temperature and pressure. While this can improve the breaking strength to some extent, the high temperature and pressure cause severe shrinkage of the meltblown fabric, and the fibers squeeze each other, leading to a reduction or even closure of the pore size. Ultimately, this results in increased density, decreased porosity, and a significant decrease in air permeability. Others use polypropylene with a higher molecular weight and narrower molecular weight distribution as the matrix material. Its polymer chains are longer and there is more inter-chain entanglement, which can enhance the strength of nonwoven fabric. However, it often requires higher processing temperature. In order to make the interlayer bonding force stronger, higher hot rolling temperature and pressure are required, which also leads to poor air permeability. Other methods involve adding additives, such as montmorillonite, kaolin, attapulgite, and calcium carbonate as filler components. These can act as nucleating agents and reinforcing phases, improving the modulus and strength of the fibers. However, directly adding fillers can clog the micropores of the spinneret, affecting production stability. Furthermore, their poor compatibility with the polypropylene matrix leads to poor dispersion of raw material components in the meltblown layer and spunbond layer, resulting in poor uniformity of the nonwoven fabric and affecting the overall stability of the nonwoven fabric.
[0005] It is evident that existing technologies, while improving the strength of SMMS nonwoven fabrics, significantly impact the product's air permeability, production stability, and overall stability of the nonwoven fabric. Summary of the Invention
[0006] To address the technical problems existing in the prior art, this invention provides an SMMS nonwoven fabric and its preparation method, which improves the strength of the nonwoven fabric while ensuring air permeability, and also has good production stability, excellent resistance to light aging, and superior overall stability.
[0007] To address the aforementioned technical problems, the present invention adopts the following technical solution: A method for preparing SMMS nonwoven fabric includes the steps of preparing a spunbond layer, preparing a meltblown layer, and lamination. The specific operations are as follows: 1. Preparation of spunbond layer (1) Preparation of reinforcing fillers N,N-dimethylformamide was heated to 100-105℃, and maleic anhydride-grafted polypropylene was added. The mixture was stirred at this temperature for 1.2-1.5 hours. After stirring, the temperature was lowered to 62-66℃, and polyoxypropylene glycol and p-toluenesulfonic acid were added. The mixture was stirred at this temperature for 35-40 minutes, and then heated to 120-130℃. The mixture was refluxed under a nitrogen atmosphere for 3.5-4.0 hours. After the reaction, a modified solution was obtained. Nano-calcium carbonate was added to the modified solution, and the temperature was controlled at 78-83℃. Polyglycerol fatty acid ester was added, and the mixture was stirred at 1000-1100 rpm for 20-25 minutes. Then, homogenization was performed for 4-5 minutes at a pressure of 2.0-3.0 MPa. After homogenization, the mixture was dried to obtain the reinforcing filler. The particle size of the nano-calcium carbonate is 200-230 nm; The mass ratio of N,N-dimethylformamide, maleic anhydride-terminated polypropylene, polyoxypropylene glycol, and p-toluenesulfonic acid is 200:15-18:3.4-4.0:0.12-0.15. The mass ratio of the nano-calcium carbonate, the modified liquid, and the polyglycerol fatty acid ester is 15:4.2-4.7:0.4-0.6. (2) Mixing and molding Polypropylene, ethylene-1-octene copolymer, reinforcing filler, oleamide, amino silicone oil, and antioxidant 1010 are mixed evenly and then extruded using a screw extruder at 180-185℃. After melt filtration, the mixture is conveyed to a spinning box, where the temperature is controlled at 200-210℃, the extrusion pressure is 5.0-5.5MPa, the side air pressure is 1.5-2.0kPa, and the temperature is 8-10℃. After stretching and web formation, a spunbond layer is obtained, with a fiber fineness of 1.1-1.4 Den. The polypropylene has a melt flow index of 25-35 g / 10 min at 190°C and 2.16 kg. The mass ratio of the polypropylene, ethylene-1-octene copolymer, reinforcing filler, oleamide, amino silicone oil, and antioxidant 1010 is 100:34-38:20-25:1.8-2.0:1.2-1.6:0.8-1.3.
[0008] 2. Preparation of meltblown layer Polylactic acid, polypropylene, meltblown additives, fillers, antioxidant 168, and ethylene bis-stearamide are mixed evenly and then extruded using a screw extruder at 190-210℃. After being filtered through melt, the mixture is conveyed to a spinning box, where the temperature is maintained at 225-235℃. The extrusion pressure in the spinning box is 1-2MPa, the side air pressure is 40-60kPa, the temperature is 220-230℃, and strong hot air with a spray pressure of 0.04-0.06MPa is used to stretch the mixture into extremely fine fibers, which then fall onto the mesh to form a meltblown layer. The fineness of the meltblown layer fibers is 0.01 Den. The melt flow index of the polypropylene is 1200-1500 g / 10 min; The mass ratio of polylactic acid, meltblown additive, filler, antioxidant 168, and ethylene bis-stearamide is 100:50-55:8.5-9.5:10-15:1.4-1.7:2.2-2.8. The method for preparing the meltblown additive is as follows: polyethylene glycol 2000 is added to anhydrous toluene and stirred evenly. Then, polycaprolactone and stannous octoate are added, the temperature is raised to 106-112℃, and the mixture is stirred and reacted under a nitrogen atmosphere for 8.5-10.0 h. After separation, washing and drying, the meltblown additive is obtained. The mass ratio of anhydrous toluene, polyethylene glycol 2000, polycaprolactone, and stannous octoate is 100:3.0-3.4:12.5-13.0:0.10-0.15. The packing material is prepared by adding montmorillonite and silica to deionized water and ball milling for 35-45 minutes at a speed of 100-110 rpm and a ball-to-material ratio of 2-4:1. After ball milling, the temperature is raised to 60-65℃, dodecyl dimethyl betaine and KH550 silane coupling agent are added, and the mixture is stirred for 2.5-3.0 hours. After filtration, washing, and drying, the packing material is obtained. The particle size of the montmorillonite is 250-270 nm; The particle size of the silica is 180-200 nm; The mass ratio of montmorillonite, silica, deionized water, dodecyl dimethyl betaine, and kH550 silane coupling agent is 7.5-8.3:4.8-5.2:120:1.4-1.7:1.2-1.6.
[0009] 3. Composite The nonwoven fabric is made by hot rolling, slitting, and winding the layers from top to bottom, consisting of a spunbond layer, a meltblown layer, a meltblown layer, and a spunbond layer. The hot rolling temperature is controlled at 145-150℃ and the hot rolling pressure is 50-60kPa.
[0010] An SMMS nonwoven fabric is prepared using the aforementioned preparation method.
[0011] This invention employs specific reinforcing fillers in the preparation of the spunbond layer. Specifically, a modified liquid is prepared by mixing maleic anhydride-grafted polypropylene and polypropylene glycol. The anhydride groups of the maleic anhydride-grafted polypropylene can react with the hydroxyl groups of the polypropylene glycol, thereby enabling the PP segments of the modified liquid to have good compatibility with the polypropylene matrix. The PPG segments interact with nano-calcium carbonate on the surface, greatly improving the dispersibility with organic polymers and inorganic fillers. Combined with components such as amino silicone oil and ethylene-1-octene copolymer, the softness, lubrication properties, and antioxidant properties are enhanced. Yes; in the meltblown layer, polylactic acid and polypropylene are compounded to balance flexibility and strength properties, and a specific method is used to prepare the meltblown additive, specifically polycaprolactone and polyethylene glycol. Polycaprolactone has high softness properties and good compatibility with polylactic acid, while polyethylene glycol can reduce melt viscosity. Combined with filler components, the mechanical properties are improved. The meltblown layer and spunbond layer prepared by this invention have good dispersibility and lubrication, effectively avoiding clogging problems during processing, improving production stability, and the synergistic effect between the spunbond layer and meltblown layer improves the air permeability of the nonwoven fabric.
[0012] Compared with the prior art, the present invention has achieved the following beneficial effects: 1. The SMMS nonwoven fabric prepared by this invention has a basis weight of 18.3-18.8 gsm, a transverse tensile strength of 52.6-55.2 N, and a longitudinal tensile strength of 57.4-60.3 N; 2. The SMMS nonwoven fabric obtained by this invention has a transverse softness of 16.8-19.4 mN, a longitudinal softness of 9.3-10.2 mN, and an air permeability of 557-568 mm / s; 3. The SMMS nonwoven fabric prepared by this invention was irradiated under a UVB-313 lamp for 14 days at an irradiation temperature of 60°C and a humidity of 50%. After the irradiation was completed, the transverse tensile strength was tested again and found to be 49.1-52.8 N, and the longitudinal tensile strength was 54.4-57.9 N. Detailed Implementation
[0013] To provide a clearer understanding of the technical features, objectives, and effects of the present invention, specific embodiments of the present invention are now described.
[0014] Example 1 1. Preparation of spunbond layer (1) Preparation of reinforcing fillers 200g of N,N-dimethylformamide was heated to 100℃, and 15g of maleic anhydride-grafted polypropylene was added. The mixture was kept at this temperature and stirred for 1.2h. After stirring, the temperature was lowered to 62℃, and 3.4g of polyoxypropylene glycol and 0.12g of p-toluenesulfonic acid were added. The mixture was kept at this temperature and stirred for 35min. The temperature was then raised to 120℃, and the mixture was refluxed under a nitrogen atmosphere for 3.5h. After the reaction was completed, a modified solution was obtained. 15g of nano-calcium carbonate was added to 4.2g of the modified solution, and the temperature was controlled at 78℃. 0.4g of polyglycerol fatty acid ester was added, and the mixture was stirred at 1000rpm for 25min. Then, homogenization was performed for 4min at a pressure of 2.0MPa. After homogenization, the mixture was dried to obtain the reinforcing filler. The particle size of the nano-calcium carbonate is 200 nm; (2) Mixing and molding 100g of polypropylene, 34g of ethylene-1-octene copolymer, 20g of reinforcing filler, 1.8g of oleamide, 1.2g of amino silicone oil, and 0.8g of antioxidant 1010 were mixed evenly and then extruded using a screw extruder at 180°C. After being filtered through melt, the mixture was conveyed to a spinning box, where the temperature was controlled at 200°C, the extrusion pressure in the spinning box was 5.0MPa, the side air pressure was 1.5kPa, and the temperature was 8°C. After stretching and web forming, a spunbond layer was obtained with a fiber fineness of 1.1 Den. The polypropylene has a melt flow index of 25 g / 10 min at 190°C and 2.16 kg.
[0015] 2. Preparation of meltblown layer 100g polylactic acid, 50g polypropylene, 8.5g meltblown additive, 10g filler, 1.4g antioxidant 168, and 2.2g ethylene bis-stearamide are mixed evenly and then extruded using a screw extruder at 190℃. After being filtered through melt, the mixture is conveyed to a spinning box and kept at a temperature of 225℃. The extrusion pressure in the spinning box is 1MPa, the side air pressure is 40kPa, the temperature is 220℃, and strong hot air with a spray pressure of 0.04MPa is used to stretch the mixture into extremely fine fibers. The fibers fall onto the mesh to obtain a meltblown layer with a fineness of 0.01 Den. The melt flow index of the polypropylene is 1200 g / 10 min; The preparation method of the meltblown additive is as follows: 3.0g of polyethylene glycol 2000 is added to 100g of anhydrous toluene, and after stirring evenly, 12.5g of polycaprolactone and 0.10g of stannous octoate are added, the temperature is raised to 106℃, and the mixture is stirred and reacted for 8.5h under a nitrogen atmosphere. After separation, washing and drying, the meltblown additive is obtained. The packing material is prepared by adding 7.5g of montmorillonite and 4.8g of silica to 120g of deionized water for ball milling. The ball milling time is 35min, the ball milling speed is 100rpm, and the ball-to-material ratio is 2:1. After ball milling, the temperature is raised to 60℃, and 1.4g of dodecyl dimethyl betaine and 1.2g of KH550 silane coupling agent are added. The mixture is stirred and reacted for 2.5h. After filtration, washing, and drying, the packing material is obtained. The particle size of the montmorillonite is 250 nm; The silicon dioxide has a particle size of 200 nm.
[0016] 3. Composite The nonwoven fabric is made by hot rolling, slitting, and winding the layers from top to bottom, consisting of a spunbond layer, a meltblown layer, a meltblown layer, and a spunbond layer. The hot rolling temperature is controlled at 145℃ and the hot rolling pressure is 50kPa.
[0017] Example 2 1. Preparation of spunbond layer (1) Preparation of reinforcing fillers 200g of N,N-dimethylformamide was heated to 105℃, and 18g of maleic anhydride-grafted polypropylene was added. The mixture was kept at this temperature and stirred for 1.5h. After stirring, the temperature was lowered to 66℃, and 4.0g of polyoxypropylene glycol and 0.15g of p-toluenesulfonic acid were added. The mixture was kept at this temperature and stirred for 40min. The temperature was then raised to 130℃, and the mixture was refluxed under a nitrogen atmosphere for 4.0h. After the reaction was completed, a modified solution was obtained. 15g of nano-calcium carbonate was added to 4.7g of the modified solution, and the temperature was controlled at 83℃. 0.6g of polyglycerol fatty acid ester was added, and the mixture was stirred at 1100rpm for 20min. Then, homogenization was performed for 4min at a pressure of 3.0MPa. After homogenization, the mixture was dried to obtain the reinforcing filler. The particle size of the nano-calcium carbonate is 230 nm; (2) Mixing and molding 100g of polypropylene, 38g of ethylene-1-octene copolymer, 25g of reinforcing filler, 2.0g of oleamide, 1.6g of amino silicone oil, and 1.3g of antioxidant 1010 were mixed evenly and then extruded using a screw extruder at 185℃. After being filtered through melt, the mixture was conveyed to a spinning box, where the temperature was controlled at 210℃, the extrusion pressure in the spinning box was 5.5MPa, the side air pressure was 2.0kPa, and the temperature was 10℃. After stretching and web forming, a spunbond layer was obtained with a fiber fineness of 1.4 Den. The polypropylene has a melt flow index of 35 g / 10 min at 190°C and 2.16 kg.
[0018] 2. Preparation of meltblown layer 100g polylactic acid, 55g polypropylene, 9.5g meltblown additive, 15g filler, 1.7g antioxidant 168, and 2.8g ethylene bis-stearamide are mixed evenly and then extruded using a screw extruder at 210℃. After being filtered through melt, the mixture is conveyed to a spinning box and kept at a temperature of 235℃. The extrusion pressure in the spinning box is 2MPa, the side air pressure is 60kPa, the temperature is 230℃, and strong hot air with a spray pressure of 0.06MPa is used to stretch the mixture into extremely fine fibers. The fibers fall onto the mesh to obtain a meltblown layer with a fiber fineness of 0.01 Den. The melt flow index of the polypropylene is 1500 g / 10 min; The method for preparing the meltblown additive is as follows: 3.4g of polyethylene glycol 2000 is added to 100g of anhydrous toluene, and after stirring evenly, 13.0g of polycaprolactone and 0.15g of stannous octoate are added, the temperature is raised to 112℃, and the mixture is stirred and reacted for 10.0h under a nitrogen atmosphere. After separation, washing and drying, the meltblown additive is obtained. The packing material is prepared by adding 8.3g of montmorillonite and 5.2g of silica to 120g of deionized water for ball milling. The ball milling time is 45min, the ball milling speed is 110rpm, and the ball-to-material ratio is 4:1. After ball milling, the temperature is raised to 65℃, and 1.7g of dodecyl dimethyl betaine and 1.6g of KH550 silane coupling agent are added. The mixture is stirred and reacted for 3.0h. After filtration, washing, and drying, the packing material is obtained. The particle size of the montmorillonite is 270 nm; The silicon dioxide has a particle size of 180 nm.
[0019] 3. Composite The nonwoven fabric is made by hot rolling, slitting, and winding the layers from top to bottom, consisting of a spunbond layer, a meltblown layer, a meltblown layer, and a spunbond layer. The hot rolling temperature is controlled at 150℃ and the hot rolling pressure is 60kPa.
[0020] Example 3 1. Preparation of spunbond layer (1) Preparation of reinforcing fillers 200g of N,N-dimethylformamide was heated to 102℃, and 16g of maleic anhydride-grafted polypropylene was added. The mixture was kept at this temperature and stirred for 1.3h. After stirring, the temperature was lowered to 65℃, and 3.6g of polyoxypropylene glycol and 0.13g of p-toluenesulfonic acid were added. The mixture was kept at this temperature and stirred for 38min. The temperature was then raised to 125℃, and the mixture was refluxed under a nitrogen atmosphere for 3.8h. After the reaction was completed, a modified solution was obtained. 15g of nano-calcium carbonate was added to 4.57g of the modified solution, and the temperature was controlled at 80℃. 0.5g of polyglycerol fatty acid ester was added, and the mixture was stirred at 1000rpm for 25min. Then, homogenization was performed for 5min at a pressure of 2.5MPa. After homogenization, the mixture was dried to obtain the reinforcing filler. The particle size of the nano-calcium carbonate is 210 nm; (2) Mixing and molding 100g of polypropylene, 36g of ethylene-1-octene copolymer, 22g of reinforcing filler, 1.8g of oleamide, 1.4g of amino silicone oil, and 1.0g of antioxidant 1010 were mixed evenly and then extruded using a screw extruder at 18285℃. After being filtered through melt, the mixture was conveyed to a spinning box, where the temperature was controlled at 205℃, the extrusion pressure in the spinning box was 5.3MPa, the side air pressure was 1.8kPa, and the temperature was 10℃. After stretching and web forming, a spunbond layer was obtained with a fiber fineness of 1.3 Den. The polypropylene has a melt flow index of 30 g / 10 min at 190°C and 2.16 kg.
[0021] 2. Preparation of meltblown layer 100g polylactic acid, 53g polypropylene, 9.0g meltblown additive, 13g filler, 1.6g antioxidant 168, and 2.5g ethylene bis-stearamide are mixed evenly and then extruded using a screw extruder at 200℃. After being filtered through melt, the mixture is conveyed to a spinning box and kept at a temperature of 2305℃. The extrusion pressure in the spinning box is 1.5MPa, the side air pressure is 50kPa, the temperature is 225℃, and strong hot air with a spray pressure of 0.05MPa is used to stretch the mixture into extremely fine fibers. The fibers fall onto the mesh to obtain a meltblown layer with a fiber fineness of 0.01 Den. The melt flow index of the polypropylene is 1300 g / 10 min; The method for preparing the meltblown additive is as follows: 3.2g of polyethylene glycol 2000 is added to 100g of anhydrous toluene, and after stirring evenly, 12.8g of polycaprolactone and 0.12g of stannous octoate are added, the temperature is raised to 110℃, and the mixture is stirred and reacted for 9.0h under a nitrogen atmosphere. After separation, washing and drying, the meltblown additive is obtained. The packing material is prepared by adding 8.0g of montmorillonite and 5.0g of silica to 120g of deionized water for ball milling. The ball milling time is 40min, the ball milling speed is 110rpm, and the ball-to-material ratio is 3:1. After ball milling, the temperature is raised to 63℃, and 1.5g of dodecyl dimethyl betaine and 1.5g of KH550 silane coupling agent are added. The mixture is stirred and reacted for 2.8h. After filtration, washing, and drying, the packing material is obtained. The particle size of the montmorillonite is 260 nm; The silicon dioxide has a particle size of 180 nm.
[0022] 3. Composite The nonwoven fabric is made by hot rolling, slitting, and winding the layers from top to bottom, consisting of a spunbond layer, a meltblown layer, a meltblown layer, and a spunbond layer. The hot rolling temperature is controlled at 148℃ and the hot rolling pressure is 55kPa.
[0023] Comparative Example 1 Based on Example 3, the change is in the preparation of the spunbond layer. In the step of preparing the reinforcing filler, the preparation of the modified liquid is omitted, and the modified liquid is replaced by an equal amount of a mixture of deionized water and kH550 silane coupling agent, wherein the mass ratio of the deionized water to the kH550 silane coupling agent is 100:1.2. In the mixing and molding step, amino silicone oil and oleamide are replaced with polypropylene components in equal amounts; All other operations are the same.
[0024] Comparative Example 2 The changes made in Example 3 are as follows: In the step of preparing the meltblown layer, the meltblown additive is replaced with an equal amount of polyethylene glycol 2000; The filler was replaced with an equal amount of a mixture of montmorillonite and silica, wherein the ratio of montmorillonite to silica was 8.0:5.0. All other operations are the same.
[0025] Performance testing 1. The basis weight and strength properties of the SMMS nonwoven fabrics prepared in Examples 1-3 and Comparative Examples 1-2 were tested. The specific test results are as follows:
[0026] 2. The softness and air permeability of the SMMS nonwoven fabrics prepared in Examples 1-3 and Comparative Examples 1-2 were tested. The specific test results are as follows:
[0027] 3. The SMMS nonwoven fabrics prepared in Examples 1-3 and Comparative Examples 1-2 were irradiated under a UVB-313 lamp for 14 days at an irradiation temperature of 60°C and a humidity of 50%. After irradiation, the intensity was tested again, and the specific test results are as follows:
[0028] Unless otherwise stated, all percentages used in this invention are mass percentages.
[0029] Finally, it should be noted that the above descriptions are merely preferred embodiments of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.
Claims
1. A method for preparing SMMS nonwoven fabric, characterized in that, This includes the steps of preparing the spunbond layer, preparing the meltblown layer, and lamination. The step of preparing the spunbond layer includes the steps of preparing reinforcing filler and mixing and molding. The steps for preparing the reinforcing filler are as follows: maleic anhydride-grafted polypropylene is added to N,N-dimethylformamide and stirred evenly. Polypropylene glycol and p-toluenesulfonic acid are then added at 62-66°C. The temperature is then raised to 120-130°C and refluxed under a nitrogen atmosphere for 3.5-4.0 hours to obtain a modified solution. Nano-calcium carbonate is added to the modified solution, and the temperature is controlled at 78-83°C. Polyglycerol fatty acid ester is then added to obtain the reinforcing filler. The step of preparing the meltblown layer is to mix polylactic acid, polypropylene, meltblown additive, filler, antioxidant 168 and ethylene bis-stearamide evenly, and then obtain the meltblown layer by extrusion, spinning and stretching. The meltblown additive is prepared by adding polyethylene glycol 2000 to anhydrous toluene, stirring until homogeneous, then adding polycaprolactone and stannous octoate, and stirring and reacting at 106-112℃ under a nitrogen atmosphere for 8.5-10.0 h to obtain the meltblown additive.
2. The method for preparing SMMS nonwoven fabric according to claim 1, characterized in that, In the step of preparing the reinforcing filler, the particle size of the nano-calcium carbonate is 200-230 nm; The mass ratio of N,N-dimethylformamide, maleic anhydride-terminated polypropylene, polyoxypropylene glycol, and p-toluenesulfonic acid is 200:15-18:3.4-4.0:0.12-0.
15. The mass ratio of the nano-calcium carbonate, the modified liquid, and the polyglycerol fatty acid ester is 15:4.2-4.7:0.4-0.
6.
3. The method for preparing SMMS nonwoven fabric according to claim 1, characterized in that, The mixing and molding step involves uniformly mixing polypropylene, ethylene-1-octene copolymer, reinforcing filler, oleamide, amino silicone oil, and antioxidant 1010, then extruding the mixture using a screw extruder at 180-185°C. After melt filtration, the mixture is conveyed to a spinning box, where the temperature is controlled at 200-210°C, the extrusion pressure in the spinning box is 5.0-5.5 MPa, the side air pressure is 1.5-2.0 kPa, and the temperature is 8-10°C. After stretching and web formation, a spunbond layer is obtained, with a fiber fineness of 1.1-1.4 Den.
4. The method for preparing SMMS nonwoven fabric according to claim 3, characterized in that, The polypropylene has a melt flow index of 25-35 g / 10 min at 190°C and 2.16 kg. The mass ratio of the polypropylene, ethylene-1-octene copolymer, reinforcing filler, oleamide, amino silicone oil, and antioxidant 1010 is 100:34-38:20-25:1.8-2.0:1.2-1.6:0.8-1.
3.
5. The method for preparing SMMS nonwoven fabric according to claim 1, characterized in that, The steps for preparing the meltblown layer are as follows: polylactic acid, polypropylene, meltblown additives, fillers, antioxidant 168, and ethylene bis-stearamide are mixed evenly and then extruded using a screw extruder at 190-210℃. After being filtered through melt, the mixture is conveyed to a spinning box, where the temperature is maintained at 225-235℃, the extrusion pressure in the spinning box is 1-2MPa, the side air pressure is 40-60kPa, the temperature is 220-230℃, and strong hot air with a spray pressure of 0.04-0.06MPa is used to stretch the mixture into extremely fine fibers, which then fall onto the mesh to obtain the meltblown layer. The fineness of the meltblown layer fibers is 0.01 Den. The melt flow index of the polypropylene is 1200-1500 g / 10 min; The mass ratio of polylactic acid, meltblown additive, filler, antioxidant 168, and ethylene bis-stearamide is 100:50-55:8.5-9.5:10-15:1.4-1.7:2.2-2.
8.
6. The method for preparing SMMS nonwoven fabric according to claim 1, characterized in that, In the preparation method of the meltblown additive, the mass ratio of anhydrous toluene, polyethylene glycol 2000, polycaprolactone and stannous octoate is 100:3.0-3.4:12.5-13.0:0.10-0.
15.
7. The method for preparing SMMS nonwoven fabric according to claim 1, characterized in that, In the step of preparing the meltblown layer, the filler is prepared by adding montmorillonite and silica to deionized water for ball milling. The ball milling time is 35-45 min, the ball milling speed is 100-110 rpm, and the ball-to-material ratio is 2-4:
1. After ball milling, the temperature is raised to 60-65℃, dodecyl dimethyl betaine and KH550 silane coupling agent are added, and the mixture is stirred and reacted for 2.5-3.0 h. After filtration, washing, and drying, the filler is obtained. The particle size of the montmorillonite is 250-270 nm; The particle size of the silica is 180-200 nm; The mass ratio of montmorillonite, silica, deionized water, dodecyl dimethyl betaine, and kH550 silane coupling agent is 7.5-8.3:4.8-5.2:120:1.4-1.7:1.2-1.
6.
8. The method for preparing SMMS nonwoven fabric according to claim 1, characterized in that, The composite process involves hot rolling, slitting, and winding the layers from top to bottom, consisting of a spunbond layer, a meltblown layer, another meltblown layer, and a spunbond layer. The hot rolling temperature is controlled at 145-150℃, and the hot rolling pressure is 50-60kPa, to obtain SMMS nonwoven fabric.
9. SMMS nonwoven fabric prepared by the preparation method according to any one of claims 1-8.