A biodegradable polypropylene nonwoven material and a method for making the same

Abstract

The application discloses a kind of biodegradable polypropylene nonwoven materials and preparation method thereof, belong to nonwoven material technical field, the preparation method is composed of the following steps: preparation biodegradable master batch, melt spinning web;The preparation biodegradable master batch, by the following steps: preparation starch liquid, preparation modified attapulgite, composite, preparation modified filler, granulation;The granulation, polylactic acid, degradation promoter, modified filler, pentaerythritol tetra stearate are added in mixer and uniformly premixed, it is added in internal mixer and carries out mixing, then using double screw extruder is granulated, obtains biodegradable master batch;Biodegradable polypropylene nonwoven material prepared by the application has fast biodegradation speed, good mechanical property and filtration performance, and preparation method is simple, without additional new equipment.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of non-woven materials, in particular to a biodegradable polypropylene non-woven material and a preparation method thereof. BACKGROUND

[0002] The polypropylene non-woven material is a kind of non-woven fabric prepared by taking polypropylene as raw material and going through processes such as melt spinning, web laying, hot rolling and bonding, and has the advantages of good air permeability, low cost and strong mechanical properties. The fiber diameter of the polypropylene non-woven material is generally only a few microns. Since the fiber diameter is very thin and irregularly stacked and entangled, it has a small through-hole with a small pore size, which ensures good air permeability of the non-woven material. In addition, the pore structure of the polypropylene non-woven material is fluffy, and when it intercepts particulate matter in the air, the fibers in the pore can fully contact the micro-nano particulate matter in the air, thereby playing its excellent mechanical trapping effect to achieve the effect of efficiently intercepting suspended particulate matter in the air. It is a kind of excellent filter material, and is widely used in many fields such as home textile products, agriculture, construction, medical and health care, and industry.

[0003] However, polypropylene material is not easy to degrade. With the increasing demand for environmental protection and high-quality products in the domestic and foreign markets, new requirements are put forward for the polypropylene non-woven material, which requires biodegradability, does not affect the mechanical properties and filtration performance of the polypropylene non-woven material, and does not increase new production equipment and additional equipment investment.

[0004] At present, in order to improve the biodegradability of the polypropylene non-woven material, there are two most commonly used methods: the first method is to add degradable resin, such as polylactic acid resin, but the addition of polylactic acid will affect the mechanical properties of the polypropylene non-woven material, and the degradation speed of the prepared polypropylene non-woven material is slow; the second method is to add natural degradable material, such as starch, but the compatibility of starch and polypropylene is poor, and the addition of starch will affect the fiber diameter of the polypropylene non-woven material, causing the fiber diameter to become larger, affecting the mechanical properties and filtration performance of the polypropylene non-woven material, and the dispersibility of starch in polypropylene is poor, and multiple high-speed mixers and homogenizers are needed for multiple mixing to achieve uniform dispersion, so high-speed mixers and homogenizers need to be additionally added in front of the production line, causing an increase in equipment investment. SUMMARY

[0005] In view of the deficiencies of the prior art, the present application provides a biodegradable polypropylene non-woven material and a preparation method thereof. The biodegradable polypropylene non-woven material prepared by the method has a fast biodegradation speed, good mechanical properties and filtration performance, and the preparation method is simple and does not require additional new equipment.

[0006] To solve the above technical problems, the technical solutions adopted by the present application are as follows:

[0007] A preparation method of a biodegradable polypropylene non-woven material, comprising the following steps: preparing a biodegradable master batch, and melt spinning into a web;

[0008] The preparation of the biodegradable master batch comprises the following steps: preparing a starch solution, preparing modified attapulgite, compounding, preparing a modified filler, and granulating;

[0009] In the preparation of the starch solution, pregelatinized starch and deionized water are added to a reaction kettle, the temperature of the reaction kettle is controlled to 40-60 DEG C, the stirring speed is controlled to 100-300 rpm, stirring is performed for 10-30 min, ionic liquid type surfactant 1-hexadecyl-3-methyl imidazole bromide and n-butanol are added, and stirring is continued for 30-50 min to obtain the starch solution;

[0010] In the preparation of the starch solution, the mass ratio of pregelatinized starch, deionized water, ionic liquid type surfactant 1-hexadecyl-3-methyl imidazole bromide, and n-butanol is 20-22:400-420:80-83:18-20;

[0011] In the preparation of the modified attapulgite, the attapulgite is completely soaked in a 5-8% mass fraction hydrochloric acid aqueous solution, completely soaked at 15-40 DEG C for 10-12 h, filtered, washed with 3-4 times the mass of the filter residue deionized water for 3-4 times, and dried at 110-140 DEG C to obtain the soaked attapulgite; the soaked attapulgite, anhydrous ethanol, deionized water, and silane coupling agent KH-550 are mixed and subjected to ultrasonic oscillation, the temperature of the ultrasonic oscillation is controlled to 40-60 DEG C, the frequency is controlled to 20-30 KHz, and the time is controlled to 50-70 min, after the ultrasonic oscillation, the filter residue is washed with 3-4 times the mass of the filter residue deionized water for 3-4 times, and the filter residue is dried at 120-140 DEG C and ground to a particle size of 200-400 mesh to obtain the modified attapulgite;

[0012] In the preparation of the modified attapulgite, the mass fraction of the hydrochloric acid aqueous solution is 5-8%;

[0013] In the preparation of the modified attapulgite, the mass ratio of the soaked attapulgite, anhydrous ethanol, deionized water, and silane coupling agent KH-550 is 130-150:500-550:50-60:25-30;

[0014] The complex, the modified attapulgite, starch liquid is added to the reaction kettle, the temperature of the reaction kettle is controlled to 80-90℃, the stirring speed is controlled to 100-300rpm, stirring for 10-30min, 32# paraffin oil is added, stirring for 40-60min, ethylene glycol, sodium trimetaphosphate is added, stirring for 1-1.5h, the temperature is lowered to 20-30℃ at a cooling rate of 1-2℃ / min, continue stirring for 30-50min, filter, use 4-5 times the mass of the filter residue of deionized water to wash the filter residue 3-4 times, the filter residue is placed in 120-140℃ oven drying, to obtain degradation accelerator;

[0015] The mass ratio of the modified attapulgite, starch liquid, 32# paraffin oil, ethylene glycol, sodium trimetaphosphate in the complex is 140-150:500-520:1800-2000:3-3.5:5-5.5;

[0016] The preparation of modified filler, sodium alginate, polyethylene glycol 400, deionized water is added to the reaction kettle, the temperature of the reaction kettle is controlled to 15-40℃, the stirring speed is controlled to 100-300rpm, stirring for 10-30min, light calcium carbonate is added, stirring for 40-60min, calcium chloride is added, stirring for 1-1.5h, cyclodextrin is added, stirring for 20-30min, epichlorohydrin is added, then sodium hydroxide solution is added dropwise, continue stirring for 4-5h after the end of dropwise addition, filter, use 4-5 times the mass of the filter residue of deionized water to wash the filter residue 3-4 times, the filter residue is placed in 110-150℃ oven drying, to obtain modified filler;

[0017] The mass ratio of sodium alginate, polyethylene glycol 400, deionized water, light calcium carbonate, calcium chloride, cyclodextrin, epichlorohydrin, sodium hydroxide solution in the preparation of modified filler is 10-11:12-15:500-520:30-35:8-10:8-9:5-6:50-55;

[0018] The mass fraction of the sodium hydroxide solution is 2-2.5%;

[0019] The dropwise addition rate of the sodium hydroxide solution is 4-5g / min;

[0020] The particle size of the light calcium carbonate is 500-800 mesh;

[0021] The granulation, polylactic acid, degradation accelerator, modified filler, pentaerythritol tetra stearate is added to the mixer for pre-mixing, added to the internal mixer for mixing, then using a twin-screw extruder for granulation, to obtain biodegradable masterbatch;

[0022] The mass ratio of polylactic acid, degradation promoter, modified filler, pentaerythritol tetra stearate in the granulation is 30-33:4-5:14-16:0.4-0.5;

[0023] The melt index of the polylactic acid is 200-400g / 10min;

[0024] The mixing temperature is 170-190℃, the rotating speed is 30-40rpm, and the time is 5-8min;

[0025] The screw temperature of the double screw extruder is 180-200℃, and the screw rotating speed is 200-300rpm;

[0026] In the melt spinning and webbing, melt blown polypropylene, biodegradable master batch, nano montmorillonite, zinc stearate and white tourmaline powder are uniformly premixed in a mixer, after mixing, melt extrusion, melt filtration, melt metering, after hot air super-drawing, the fiber is cooled and solidified and deposited on the webbing device, and is wound into a webbing to obtain a biodegradable polypropylene non-woven material;

[0027] In the melt spinning and webbing, the mass ratio of melt blown polypropylene, biodegradable master batch, nano montmorillonite, zinc stearate and white tourmaline powder is 60-65:14-16:6-8:1.2-1.5:0.3-0.4;

[0028] The melt index of the melt blown polypropylene is 1200-1500g / 10min;

[0029] The particle size of the nano montmorillonite is 50-80nm;

[0030] The particle size of the nano white tourmaline powder is 12000-13000 mesh;

[0031] The screw temperature of the double screw extruder used in the melt extrusion is 190-220℃, and the screw rotating speed is 200-250rpm;

[0032] The filter temperature in the melt filtration is 220-230℃;

[0033] The metering pump temperature in the melt metering is 220-230℃;

[0034] The air temperature in the hot air super-drawing is 200-210℃.

[0035] A biodegradable polypropylene non-woven material is prepared by the preparation method.

[0036] Compared with the prior art, the biodegradable polypropylene non-woven material has the advantages that:

[0037] (1) The preparation method of the biodegradable polypropylene non-woven material of the present application can improve the biodegradation rate of the prepared biodegradable polypropylene non-woven material by adding a degradation promoter and a modified filler in the biodegradable masterbatch, and the 180d biocompost degradation rate of the biodegradable polypropylene non-woven material prepared by the present application is 85-86%;

[0038] (2) The preparation method of the biodegradable polypropylene non-woven material of the present application can improve the mechanical properties of the prepared biodegradable polypropylene non-woven material by adding a degradation promoter and a modified filler in the biodegradable masterbatch, and the transverse tensile strength of the biodegradable polypropylene non-woven material prepared by the present application is 67-69MPa, the longitudinal tensile strength is 57-59MPa, the transverse elongation at break is 240-245%, and the longitudinal elongation at break is 195-197%;

[0039] (3) The preparation method of the biodegradable polypropylene non-woven material of the present application can improve the filtration performance of the prepared biodegradable polypropylene non-woven material by adding a degradation promoter in the biodegradable masterbatch, and the diameter of the biodegradable polypropylene non-woven material prepared by the present application is 1.9-2.2μm, the grammage is 60-65gsm, the porosity is 62-64%, and the filtration efficiency of 0.3μm particle size dust source is 99.0-99.3%;

[0040] (4) The preparation method of the biodegradable polypropylene non-woven material of the present application is simple and does not need to add new equipment. DETAILED DESCRIPTION

[0041] In order to have a clearer understanding of the technical features, objects and effects of the present application, the specific embodiments of the present application will be described.

[0042] Example 1

[0043] A preparation method of a biodegradable polypropylene non-woven material, specifically:

[0044] 1. Preparation of biodegradable masterbatch:

[0045] (1) Preparation of starch solution: 20g of pregelatinized starch, 400g of deionized water is added into the reaction kettle, the temperature of the reaction kettle is controlled to 40℃, the stirring speed is controlled to 100rpm, stirring for 10min, 80g of ionic liquid type surfactant 1-hexadecyl-3-methyl imidazole bromide, 18-20g of n-butanol is added, and stirring is continued for 30min to obtain the starch solution;

[0046] (2) Preparation of modified attapulgite: The attapulgite was completely immersed in a 5% hydrochloric acid aqueous solution, completely immersed at 15°C for 10 hours, filtered, washed with 3 times the mass of deionized water of the filter residue 3 times, and dried at 110°C to obtain the soaked attapulgite; 130g of the soaked attapulgite, 500g of anhydrous ethanol, 50g of deionized water, and 25g of silane coupling agent KH-550 were mixed and ultrasonically oscillated, the ultrasonic oscillation temperature was controlled at 40°C, the frequency was 20KHz, and the time was 50min; after ultrasonic oscillation, the mixture was filtered, washed with 3 times the mass of deionized water of the filter residue 3 times, and dried at 120°C to obtain the modified attapulgite;

[0047] (3) Compound: 140g of the modified attapulgite and 500g of starch solution were added to a reaction kettle, the temperature of the reaction kettle was controlled at 80°C, the stirring speed was controlled at 100rpm, stirring was performed for 10min, 1800g of 32# paraffin oil was added, stirring was performed for 40min, 3g of ethylene glycol and 5g of sodium trimetaphosphate were added, stirring was performed for 1h, the temperature was lowered to 20°C at a rate of 1°C / min, and stirring was continued for 30min, then the mixture was filtered, washed with 4 times the mass of deionized water of the filter residue 3 times, and dried at 120°C to obtain the degradation promoter;

[0048] (4) Preparation of modified filler: 10g of sodium alginate, 12g of polyethylene glycol 400, and 500g of deionized water were added to a reaction kettle, the temperature of the reaction kettle was controlled at 15°C, the stirring speed was controlled at 100rpm, stirring was performed for 10min, 30g of light calcium carbonate was added, stirring was performed for 40min, 8g of calcium chloride was added, stirring was performed for 1-1.5h, 8g of cyclodextrin was added, stirring was performed for 20min, 5g of epichlorohydrin was added, and then 50-55g of a 2% sodium hydroxide aqueous solution was added dropwise at a rate of 4g / min, after the dropwise addition was completed, stirring was continued for 4h, then the mixture was filtered, washed with 4 times the mass of deionized water of the filter residue 3 times, and dried at 110°C to obtain the modified filler;

[0049] The particle size of the light calcium carbonate is 500 meshes;

[0050] (5) Granulation: 30kg of polylactic acid, 4kg of the degradation promoter, 14kg of the modified filler, and 0.4kg of pentaerythritol tetrastearate were uniformly premixed in a mixer, mixed in an internal mixer, and then granulated using a twin-screw extruder to obtain a biodegradable masterbatch;

[0051] The melt index of the polylactic acid is 200g / 10min;

[0052] The mixing temperature is 170°C, the rotation speed is 30rpm, and the time is 5min;

[0053] The screw temperature of the double screw extruder is 180℃, and the screw rotation speed is 200rpm;

[0054] 2. Melt spinning and webbing: 60kg of melt blown polypropylene, 14kg of biodegradable masterbatch, 6kg of nano montmorillonite, 1.2kg of zinc stearate, and 0.3kg of white tourmaline powder are added to a mixer for pre-mixing, after mixing, melt extrusion, melt filtration, melt metering, after hot air super-drawing, the fibers are cooled and solidified and deposited on a webbing device, and wound into a web to obtain a biodegradable polypropylene non-woven material;

[0055] The melt index of the melt blown polypropylene is 1200g / 10min;

[0056] The particle size of the nano montmorillonite is 50nm;

[0057] The particle size of the nano white tourmaline powder is 12000 mesh;

[0058] The screw temperature of the double screw extruder used in the melt extrusion is 190℃, and the screw rotation speed is 200rpm;

[0059] The filter temperature in the melt filtration is 220℃;

[0060] The metering pump temperature in the melt metering is 220℃;

[0061] The air temperature in the hot air super-drawing is 200℃;

[0062] The fiber diameter of the biodegradable polypropylene non-woven material is 1.9μm, and the grammage is 60gsm.

[0063] Example 2

[0064] A method for preparing a biodegradable polypropylene non-woven material, specifically:

[0065] 1. Preparation of biodegradable masterbatch:

[0066] (1) Preparation of starch solution: 21g of pregelatinized starch, 410g of deionized water are added to a reaction kettle, the temperature of the reaction kettle is controlled to 50℃, the stirring speed is controlled to 200rpm, stirring for 20min, 81g of ionic liquid type surfactant 1-hexadecyl-3-methyl imidazole bromide, 19g of n-butanol are added, and stirring is continued for 40min to obtain a starch solution;

[0067] (2) Preparation of modified attapulgite: The attapulgite was completely immersed in a 6% hydrochloric acid aqueous solution, completely immersed at 30℃ for 11h, filtered, washed with 3-4 times the mass of deionized water of the filter residue 3 times, and dried at 130℃ to obtain the soaked attapulgite; 140g of the soaked attapulgite, 520g of anhydrous ethanol, 55g of deionized water, and 28g of silane coupling agent KH-550 were mixed and ultrasonically oscillated, the ultrasonic oscillation temperature was controlled at 50℃, the frequency was 25KHz, and the time was 60min; after ultrasonic oscillation, filtration was performed, the filter residue was washed with 3 times the mass of deionized water of the filter residue 3 times, and the filter residue was dried at 130℃ and ground to a particle size of 300 mesh to obtain the modified attapulgite;

[0068] (3) Compound: 145g of the modified attapulgite and 510g of starch liquid were added to a reaction kettle, the temperature of the reaction kettle was controlled to 85℃, the stirring speed was controlled to 200rpm, stirring was performed for 20min, 1900g of 32# paraffin oil was added, stirring was performed for 50min, 3.2g of ethylene glycol and 5.2g of sodium trimetaphosphate were added, stirring was performed for 1.2h, the temperature was lowered to 25℃ at a cooling rate of 1.5℃ / min, and stirring was continued for 40min, filtration was performed, the filter residue was washed with 5 times the mass of deionized water of the filter residue 4 times, and the filter residue was dried at 130℃ to obtain a degradation promoter;

[0069] (4) Preparation of modified filler: 10.5g of sodium alginate, 13g of polyethylene glycol 400, and 510g of deionized water were added to a reaction kettle, the temperature of the reaction kettle was controlled to 30℃, the stirring speed was controlled to 200rpm, stirring was performed for 20min, 32g of light calcium carbonate was added, stirring was performed for 50min, 9g of calcium chloride was added, stirring was performed for 1.2h, 8.5g of cyclodextrin was added, stirring was performed for 25min, 5.5g of epichlorohydrin was added, then 52g of a 2.2% sodium hydroxide aqueous solution was added dropwise at a rate of 4.5g / min, stirring was continued for 4.5h after the dropwise addition was completed, filtration was performed, the filter residue was washed with 4 times the mass of deionized water of the filter residue 3 times, and the filter residue was dried at 120℃ to obtain a modified filler;

[0070] The particle size of the light calcium carbonate is 600 mesh;

[0071] (5) Granulation: 32kg of polylactic acid, 4.5kg of a degradation promoter, 15kg of a modified filler, and 0.4kg of pentaerythritol tetrastearate were uniformly premixed in a mixer, mixed in an internal mixer, then granulated using a twin-screw extruder to obtain a biodegradable masterbatch;

[0072] The melt index of the polylactic acid is 300g / 10min;

[0073] The mixing temperature is 180℃, the rotating speed is 35rpm, and the time is 6min;

[0074] The screw temperature of the double screw extruder is 190℃, and the screw rotating speed is 250rpm;

[0075] 2. Melt spinning and webbing: 62kg of melt blown polypropylene, 15kg of biodegradable masterbatch, 7kg of nano montmorillonite, 1.3kg of zinc stearate, and 0.3kg of white tourmaline powder are added to a mixer for pre-mixing, after mixing, melt extrusion, melt filtration, melt metering, after hot air super-drawing, the fibers are cooled and solidified and deposited on a webbing device, and wound into a web to obtain a biodegradable polypropylene non-woven material;

[0076] The melt index of the melt blown polypropylene is 1300g / 10min;

[0077] The particle size of the nano montmorillonite is 60nm;

[0078] The particle size of the nano white tourmaline powder is 12500 mesh;

[0079] The screw temperature of the double screw extruder used in the melt extrusion is 210℃, and the screw rotating speed is 220rpm;

[0080] The filter temperature in the melt filtration is 225℃;

[0081] The metering pump temperature in the melt metering is 225℃;

[0082] The air temperature in the hot air super-drawing is 205℃;

[0083] The fiber diameter of the biodegradable polypropylene non-woven material is 2μm, and the grammage is 62gsm.

[0084] Example 3

[0085] A preparation method of a biodegradable polypropylene non-woven material, specifically:

[0086] 1. Preparation of biodegradable masterbatch:

[0087] (1) Preparation of starch solution: 22g of pregelatinized starch, 420g of deionized water are added to a reaction kettle, the temperature of the reaction kettle is controlled to 60℃, the stirring speed is controlled to 300rpm, stirring for 30min, 83g of ionic liquid type surfactant 1-hexadecyl-3-methyl imidazole bromide, 20g of n-butanol are added, and stirring is continued for 50min to obtain a starch solution;

[0088] (2) Preparation of modified attapulgite: The attapulgite was completely immersed in an 8% hydrochloric acid aqueous solution, completely immersed at 40℃ for 12h, filtered, washed with 4 times the mass of deionized water of the filter residue 4 times, and dried at 140℃ to obtain the soaked attapulgite; 150g of the soaked attapulgite, 550g of anhydrous ethanol, 60g of deionized water, and 30g of silane coupling agent KH-550 were mixed and ultrasonically oscillated, the ultrasonic oscillation temperature was controlled at 60℃, the frequency was 30KHz, and the time was 70min; after ultrasonic oscillation, the mixture was filtered, washed with 4 times the mass of deionized water of the filter residue 4 times, and dried at 140℃ to obtain the modified attapulgite;

[0089] (3) Compounding: 150g of the modified attapulgite and 520g of starch liquid were added to a reaction kettle, the temperature of the reaction kettle was controlled at 90℃, the stirring speed was controlled at 300rpm, and stirring was performed for 30min; 2000g of 32# paraffin oil was added and stirred for 60min; 3.5g of ethylene glycol and 5.5g of sodium trimetaphosphate were added and stirred for 1.5h; the temperature was lowered to 30℃ at a rate of 2℃ / min, and stirring was continued for 50min; the mixture was filtered, washed with 5 times the mass of deionized water of the filter residue 4 times, and dried at 140℃ to obtain the degradation promoter;

[0090] (4) Preparation of modified filler: 11g of sodium alginate, 15g of polyethylene glycol 400, and 520g of deionized water were added to a reaction kettle, the temperature of the reaction kettle was controlled at 40℃, the stirring speed was controlled at 300rpm, and stirring was performed for 30min; 35g of light calcium carbonate was added and stirred for 60min; 10g of calcium chloride was added and stirred for 1.5h; 9g of cyclodextrin was added and stirred for 30min; 6g of epichlorohydrin was added, and then 55g of a 2.5% sodium hydroxide aqueous solution was added dropwise at a rate of 5g / min; after the dropwise addition was completed, stirring was continued for 5h; the mixture was filtered, washed with 5 times the mass of deionized water of the filter residue 4 times, and dried at 150℃ to obtain the modified filler;

[0091] The particle size of the light calcium carbonate is 800 meshes;

[0092] (5) Granulation: 33kg of polylactic acid, 5kg of the degradation promoter, 16kg of the modified filler, and 0.5kg of pentaerythritol tetrastearate were uniformly premixed in a mixer, mixed in an internal mixer, and then granulated using a twin-screw extruder to obtain a biodegradable masterbatch;

[0093] The melt index of the polylactic acid is 400g / 10min;

[0094] The mixing temperature is 190℃, the rotation speed is 40rpm, and the time is 8min;

[0095] The screw temperature of the double screw extruder is 200℃, and the screw rotation speed is 300rpm;

[0096] 2. Melt spinning and webbing: 65kg of melt-blown polypropylene, 16kg of biodegradable masterbatch, 8kg of nano-montmorillonite, 1.5kg of zinc stearate, and 0.4kg of white tourmaline powder are added to a mixer for pre-mixing, after which melt extrusion, melt filtration, melt metering, and hot air super-drawing are performed, and the fibers are cooled, solidified, and deposited on a webbing device, and then wound into a web to obtain a biodegradable polypropylene non-woven material;

[0097] The melt index of the melt-blown polypropylene is 1500g / 10min;

[0098] The particle size of the nano-montmorillonite is 80nm;

[0099] The particle size of the nano-white tourmaline powder is 13000 mesh;

[0100] The screw temperature of the double screw extruder used in the melt extrusion is 220℃, and the screw rotation speed is 250rpm;

[0101] The filter temperature in the melt filtration is 230℃;

[0102] The metering pump temperature in the melt metering is 230℃;

[0103] The air temperature in the hot air super-drawing is 210℃;

[0104] The fiber diameter of the biodegradable polypropylene non-woven material is 2.2μm, and the grammage is 65gsm.

[0105] Comparative Example 1

[0106] The preparation method of the biodegradable polypropylene non-woven material described in Example 1 is used, except that in the step of preparing the biodegradable masterbatch in the first step, steps (1)-(3) are omitted, and in the step of granulation in step (5), pregelatinized starch is used instead of the addition of the same amount of degradation promoter.

[0107] The fiber diameter of the biodegradable polypropylene non-woven material is 3.4μm, and the grammage is 77gsm.

[0108] Comparative Example 2

[0109] The preparation method of the biodegradable polypropylene non-woven material described in Example 1 is used, except that in the step of preparing the biodegradable masterbatch in the first step, step (4) is omitted, and in the step of granulation in step (5), light calcium carbonate is used instead of the addition of the same amount of modified filler.

[0110] The biodegradable polypropylene nonwoven material has a fiber diameter of 2 μm and a grammage of 57 gsm.

[0111] Test Example 1

[0112] The 180d biocomposting degradation rate, transverse tensile strength, longitudinal tensile strength, transverse elongation at break, longitudinal elongation at break, porosity, and filtration efficiency for 0.3 μm particle size dust source of the biodegradable polypropylene nonwoven materials prepared in Examples 1-3 and Comparative Examples 1-2 were tested, and the test results are as follows:

[0113]

[0114] As can be seen from the above results, by adding a degradation promoter to the biodegradable masterbatch, the fiber diameter of the prepared biodegradable polypropylene nonwoven material can be reduced, and the 180d biocomposting degradation rate, transverse tensile strength, longitudinal tensile strength, transverse elongation at break, longitudinal elongation at break, porosity, and filtration efficiency for 0.3 μm particle size dust source of the prepared biodegradable polypropylene nonwoven material can be improved;

[0115] By adding a modified filler to the biodegradable masterbatch, the 180d biocomposting degradation rate, transverse tensile strength, longitudinal tensile strength, transverse elongation at break, and longitudinal elongation at break of the prepared biodegradable polypropylene nonwoven material can be improved;

[0116] The degradation promoter is a composite of attapulgite and pregelatinized starch, specifically, the pregelatinized starch activated using a surfactant is compounded with the attapulgite modified using a silane coupling agent, the pregelatinized starch is adsorbed on the surface of the attapulgite, and then glycol and sodium trimetaphosphate are added for crosslinking, so that the pregelatinized starch adsorbed on the surface of the attapulgite forms a crosslinked three-dimensional network structure; the addition of attapulgite and pregelatinized starch can promote the degradation of polypropylene nonwoven material, and the three-dimensional network structure can improve the connectivity between the degradation promoter and polypropylene, thereby improving the mechanical properties of the prepared polypropylene nonwoven material; in addition, compared with directly adding pregelatinized starch, the degradation promoter has a smaller particle size, stronger dispersibility in polypropylene, and stronger bonding force with polypropylene, and is easier to stretch, thereby reducing the diameter of the prepared polypropylene nonwoven material and improving the porosity.

[0117] The preparation method of the modified filler is that the hydrogel cross-linked by sodium alginate and calcium chloride is coated on the surface of light calcium carbonate, and then cyclodextrin is grafted; the presence of cyclodextrin can improve the flowability of the filler in polypropylene and the compatibility with polypropylene, and further promote the degradation of polypropylene non-woven material; the hydrogel cross-linked by sodium alginate and calcium chloride is coated on the surface of light calcium carbonate, which is to better graft cyclodextrin, and to avoid the aggregation of light calcium carbonate in the grafting process, so as to avoid the uneven grafting leading to the decrease of the mechanical properties of polypropylene non-woven material, thereby solving the problem that the addition of polylactic acid affects the mechanical properties of polypropylene non-woven material.

[0118] Unless otherwise stated, the percentages used in the present application are mass percentages.

[0119] Finally, it should be noted that: the above only describes the preferred embodiments of the present application, and is not intended to limit the present application, although the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions recorded in the foregoing embodiments, or make equivalent replacement for part of the technical features. Any modification, equivalent replacement, improvement, etc. made within the spirit and principles of the present application shall be included in the protection scope of the present application.

Claims

1. A method for preparing a biodegradable polypropylene nonwoven material, characterized in that, It consists of the following steps: preparing biodegradable masterbatch and melt spinning it into a web; The preparation of the biodegradable masterbatch consists of the following steps: preparing starch solution, preparing modified attapulgite, compounding, preparing modified filler, and granulation. To prepare the starch solution, pregelatinized starch and deionized water are added to a reaction vessel, the temperature of the reaction vessel is controlled to 40-60℃, and the mixture is stirred. Then, ionic liquid surfactants 1-hexadecyl-3-methylimidazole bromide and n-butanol are added, and stirring is continued to obtain the starch solution. The preparation of modified attapulgite involves completely immersing attapulgite in a 5-8% hydrochloric acid aqueous solution at 15-40°C, filtering, washing, and drying the filter residue to obtain the soaked attapulgite; then mixing the soaked attapulgite with anhydrous ethanol, deionized water, and silane coupling agent KH-550, followed by ultrasonic vibration, filtering, washing, drying, and grinding the filter residue to obtain the modified attapulgite. The process involves adding modified attapulgite clay and starch solution to a reactor, controlling the reactor temperature to 80-90℃, stirring, adding 32# paraffin oil, stirring, adding ethylene glycol and sodium trimetaphosphate, stirring, cooling to 20-30℃, continuing stirring, filtering, washing and drying the filter residue to obtain a degradation promoter. To prepare the modified filler, sodium alginate, polyethylene glycol 400, and deionized water are added to a reaction vessel. The temperature of the reaction vessel is controlled at 15-40℃. The mixture is stirred, then light calcium carbonate is added and stirred. Calcium chloride is added and stirred. Cyclodextrin is added and stirred. Epichlorohydrin is added, and then sodium hydroxide aqueous solution is added dropwise. After the dropwise addition is completed, stirring is continued. The mixture is filtered, washed, and dried to obtain the modified filler. The granulation process involves premixing polylactic acid, degradation accelerator, modified filler, and pentaerythritol tetrastearate in a mixer, then mixing them in an internal mixer, and finally granulating them using a twin-screw extruder to obtain biodegradable masterbatch. The melt spinning process involves adding meltblown polypropylene, biodegradable masterbatch, nano-montmorillonite, zinc stearate, and white tourmaline powder to a mixer for premixing. After mixing, the mixture undergoes melt extrusion, melt filtration, and melt metering. Then, it is subjected to super-stretching by hot airflow. The fibers are cooled, solidified, and deposited on a web-collecting device, which then winds them into a web to obtain biodegradable polypropylene nonwoven material.

2. The method for preparing the biodegradable polypropylene nonwoven material according to claim 1, characterized in that, In the preparation of the starch solution, the mass ratio of pregelatinized starch, deionized water, ionic liquid surfactant 1-hexadecyl-3-methylimidazole bromide, and n-butanol is 20-22:400-420:80-83:18-20.

3. The method for preparing the biodegradable polypropylene nonwoven material according to claim 1, characterized in that, In the preparation of the modified attapulgite, the mass fraction of the hydrochloric acid aqueous solution is 5-8%. The mass ratio of soaked attapulgite clay, anhydrous ethanol, deionized water, and silane coupling agent KH-550 is 130-150:500-550:50-60:25-30.

4. The method for preparing the biodegradable polypropylene nonwoven material according to claim 1, characterized in that, In the composite, the mass ratio of modified attapulgite clay, starch liquid, 32# paraffin oil, ethylene glycol, and sodium trimetaphosphate is 140-150:500-520:1800-2000:3-3.5:5-5.

5.

5. The method for preparing the biodegradable polypropylene nonwoven material according to claim 1, characterized in that, In the preparation of the modified filler, the mass ratio of sodium alginate, polyethylene glycol 400, deionized water, light calcium carbonate, calcium chloride, cyclodextrin, epichlorohydrin, and sodium hydroxide aqueous solution is 10-11:12-15:500-520:30-35:8-10:8-9:5-6:50-55. The sodium hydroxide aqueous solution has a mass fraction of 2-2.5%; The sodium hydroxide aqueous solution was added at a rate of 4-5 g / min; The light calcium carbonate has a particle size of 500-800 mesh.

6. The method for preparing the biodegradable polypropylene nonwoven material according to claim 1, characterized in that, In the granulation process, the mass ratio of polylactic acid, degradation accelerator, modified filler, and pentaerythritol tetrastearate is 30-33:4-5:14-16:0.4-0.

5. The melt index of the polylactic acid is 200-400 g / 10 min; The mixing temperature is 170-190℃, the rotation speed is 30-40rpm, and the time is 5-8min; The screw temperature of the twin-screw extruder is 180-200℃, and the screw speed is 200-300rpm.

7. The method for preparing the biodegradable polypropylene nonwoven material according to claim 1, characterized in that, In the melt-spun web formation, the mass ratio of meltblown polypropylene, biodegradable masterbatch, nano-montmorillonite, zinc stearate, and white tourmaline powder is 60-65:14-16:6-8:1.2-1.5:0.3-0.

4. The melt flow index of the meltblown polypropylene is 1200-1500 g / 10 min; The particle size of the nano-montmorillonite is 50-80 nm; The white tourmaline powder has a particle size of 12,000-13,000 mesh; The screw temperature of the twin-screw extruder used in the melt extrusion is 190-220℃, and the screw speed is 200-250rpm; The filter temperature in the melt filtration is 220-230℃; The temperature of the metering pump in the melt metering is 220-230℃; The air temperature in the super-stretching of the hot airflow is 200-210℃.

8. A biodegradable polypropylene nonwoven material, characterized in that, It is prepared by the preparation method according to any one of claims 1-7.

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