Medical high-performance polylactic acid spunlace composite non-woven material and preparation method thereof

Abstract

The invention relates to the technical field of spunlace non-woven materials, and particularly discloses a medical high-performance polylactic acid spunlace composite non-woven material and a preparation method thereof.The preparation method comprises the steps that firstly, polylactic acid fibers and crude natural cellulose fibers are modified, and a compatilizer PLGA-PEG-MDI segmented copolymer is prepared; the preparation process of the spunlace composite non-woven material comprises the steps that viscose is subjected to plasma activation, a compatilizer is sprayed to be loosened and mixed with modified polylactic acid fibers, cross lapping is carried out, polylactic acid added with the compatilizer is melt-blown to the surface of the lapping, and the spunlace composite non-woven material is obtained. And finally, paving the modified crude natural cellulose on the surface of the melt-blown layer to form the spunlace composite non-woven material with good antibacterial property, one-way wet permeability and degradability.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of water-jet non-woven materials, in particular to a medical high-performance polylactic acid water-jet composite non-woven material and a preparation method thereof. BACKGROUND

[0002] Medical protective products include medical protective clothing and medical dressings and other products. At present, the medical protective products on the market are mostly made of polyethylene, polypropylene and other high molecular polymers through a series of processes such as spun-bonding, melt-blowing, film coating and flash evaporation. Since the raw materials of these protective products are mostly traditional petroleum-based compounds, they have the shortcomings of being difficult to degrade, poor comfort, poor air and moisture permeability, and hot wearing, which brings great physical burden to medical staff and causes environmental hazards.

[0003] Polylactic acid fiber is a green and environmentally friendly fiber, and its raw material is lactic acid, which is mainly obtained by fermentation of starch (corn, rice) and the like. After the product is made, it can be quickly decomposed in a natural state. Due to its natural degradability, moisture absorption and permeability, natural antibacterial property, softness and comfort, it can be widely used in medical and health products, household and decorative markets, and clothing markets, and the energy consumption in the production process is only 20%-50% of that of petroleum chemical products, and the carbon dioxide generated is only 20% of that of petroleum chemical products. Therefore, it is necessary to develop composite materials based on polylactic acid fiber to alleviate global environmental and energy problems. SUMMARY

[0004] The purpose of the present application is to provide a medical high-performance polylactic acid water-jet composite non-woven material and a preparation method thereof, which uses degradable fibers to form a medical composite material with good antibacterial performance and directional moisture management performance, and is applied to medical protection and medical dressings, solving the problems of traditional petroleum-based medical protective materials, such as difficulty in degradation, poor comfort, poor air and moisture permeability, and hot wearing.

[0005] In order to solve the above technical problems, the present application provides the following technical scheme: A preparation method of a medical high-performance polylactic acid water-jet composite non-woven material, specifically comprising: Step 1: after the viscose fiber is plasma-activated, spray PLGA-PEG-MDI block copolymer ethanol solution, and then mix and cross-lay with zinc oxide-RAFT grafted polylactic acid fiber; Step 2: after mixing the polylactic acid granules with the PLGA-PEG-MDI block copolymer, melt blowing is performed on the laid web formed in step 1 to form an intermediate layer, and then pre-water jet is fixed; Step 3: the attapulgite-chitosan modified coarse natural cellulose fiber is laid on the pre-water jet fixed intermediate layer, and then water jet reinforcement, drying and winding are performed to obtain the medical high-performance polylactic acid water-jet composite non-woven material.

[0006] The gas used in the plasma activation is a mixture of helium and oxygen, the volume ratio of helium and oxygen is (8-9):(1-2), the power is 180-200w, and the activation time is 3-5min; the airflow assistance is used in the laying, the airflow speed is 0.8-1m / s, and the angle between the airflow and the laying is 15-20°.

[0007] After the viscose fiber is plasma activated, a large number of hydroxyl groups (-OH) and carboxyl groups (-COOH) exist on the surface, these active groups react with the isocyanate groups (-NCO) of the copolymer, the hydroxyl groups condense with the isocyanate to form urethane covalent bonds, the carboxyl groups react with the isocyanate groups to form amide bonds, the PLGA block of the copolymer interpenetrates and entangles with the polylactic acid molecular chain to form a physical bonding network, so that the interfacial compatibility between the polylactic acid and the viscose fiber is greatly improved, and the interface delamination between the melt-blown polylactic acid fiber layer and the viscose fiber substrate is inhibited; the PEG block of the copolymer reduces the melt viscosity and plays a plasticizing effect; in addition, the PLGA block dynamically coordinates the degradation behavior of the composite material by virtue of the degradation rate between polylactic acid and cellulose.

[0008] As a limitation of the present application, in step 1, the preparation method of zinc oxide-RAFT grafted polylactic acid fiber is: After mixing ethanol and deionized water uniformly, betaine methacrylic acid sulfonic acid is added, after stirring at 60-70℃, 300-400rpm for 20-25min, photoinitiator 2959 is added, oxygen is removed by nitrogen bubbling for 10-15min, and a betaine ethanol dispersion is obtained, polylactic acid fiber is added to the betaine ethanol dispersion, and after immersion at 60-70℃, 300-400rpm for 15-20min, it is taken out, and grafted under the protection of nitrogen and 365nm ultraviolet light irradiation for 60-120s, the irradiation intensity is 25-35mW / cm 2 , to obtain grafted RAFT polylactic acid, the grafted RAFT polylactic acid is immersed in an ethanol dispersion containing carboxymethyl cellulose sodium and quaternary ammonium salt chitosan coated nano zinc oxide, and then taken out after vacuum assisted immersion at (-0.08)-(-0.09)MPa for 15-20min, solidified at 50-60℃ for 20-30min, and then solidified at 60-70℃ for 20-30min, to obtain zinc oxide-RAFT grafted polylactic acid fiber.

[0009] Under the action of ultraviolet light irradiation and photoinitiator 2959, betaine methacrylic acid sulfonic acid forms a thioester bond (-C(=S)S-) covalently connected with polylactic acid through chain transfer reaction, on the other hand, the sulfonic acid group (-SO3 -) and the hydroxyl group (-OH) of viscose fibers form a strong hydrogen bond network, enhancing the interfacial compatibility of polylactic acid and viscose fibers; the grafted methacrylic acid sulfobetaine can form hydrophilic microdomains on the side of polylactic acid due to its zwitterionic characteristics, enhancing the moisture conductivity of the composite material; the finished quaternary ammonium salt chitosan coated nano zinc oxide can destroy the bacterial biofilm and the active oxygen (·OH) activated by zinc oxide, thereby synergistically resisting bacteria, and the chitosan coating layer forms a slow-release structure, reducing the release rate of zinc ions and enhancing the antibacterial effect. + (CH3)3) destroy bacterial biofilms and active oxygen (·OH) activated by zinc oxide, thereby synergistically resisting bacteria, and the chitosan coating layer forms a slow-release structure, reducing the release rate of zinc ions and enhancing the antibacterial effect.

[0010] As a limitation of the present application, the volume ratio of ethanol and deionized water in the betaine ethanol dispersion is (7-8):(2-3), and the concentration of methacrylic acid sulfobetaine is 0.5-0.6 g / mL; the ethanol dispersion contains 0.1-0.2wt% sodium carboxymethyl cellulose and 3-5wt% quaternary ammonium salt chitosan coated nano zinc oxide.

[0011] As a limitation of the present application, the preparation method of the quaternary ammonium salt chitosan coated nano zinc oxide is as follows: Silane coupling agent KH-550 is added to ethanol, and after stirring at 300-400 rpm for 15-20 min at 25-30℃, nano zinc oxide is added, the temperature is raised to 65-70℃, and reflux reaction is carried out at 300-400 rpm for 3-4 h; after the reaction is completed, filtration is carried out, washing is carried out with ethanol and acetone, and vacuum drying is carried out at 50-60℃ for 3-4 h to obtain silane modified nano zinc oxide; Quaternary ammonium salt chitosan is added to acetic acid solution, stirring is carried out at 400-500 rpm for 1-2 h at 40-50℃ to obtain quaternary ammonium salt chitosan solution, and silane modified nano zinc oxide and polyethylene glycol are added to the quaternary ammonium salt chitosan solution, reaction is carried out in a water bath at 50-60℃ at 200-300 rpm for 2-3 h, centrifugal separation is carried out after the reaction is completed, and freeze-drying is carried out for 3-4 h to obtain quaternary ammonium salt chitosan coated nano zinc oxide.

[0012] The mass ratio of silane coupling agent KH-550 and nano zinc oxide is (0.8-1.0):(30-40), the concentration of the quaternary ammonium salt chitosan solution is 0.15-0.2 g / mL, and the mass ratio of silane modified nano zinc oxide, polyethylene glycol and quaternary ammonium salt chitosan solution is (70-80):(4-6):(75-85).

[0013] As a limitation of the present application, the preparation method of the PLGA-PEG-MDI block copolymer is as follows: Under the protection of nitrogen, lactic acid, hydroxyacetic acid and stannous octoate are mixed and reacted at 160-170 DEG C for 3-4 h, after the reaction is completed, the temperature is lowered to 150-160 DEG C, and vacuum dehydration is carried out at (-0.08)-(-0.09) MPa for 2-3 h, to obtain a PLGA prepolymer, the PLGA prepolymer is mixed with polyethylene glycol, and tetrabutyl titanate is added for catalysis, and polycondensation is carried out at 130-140 DEG C and 0.08-0.1 MPa for 3-5 h, after the polycondensation is completed, the temperature is lowered to 80-90 DEG C, and diphenylmethane diisocyanate is added, and reaction is carried out under the protection of nitrogen for 1-2 h, after the reaction is completed, phosphoric acid is added to terminate the reaction, to obtain a PLGA-PEG-MDI block copolymer.

[0014] As a limitation of the application, the mass ratio of lactic acid, hydroxyacetic acid and stannous octoate is (55-65):(15-25):(0.04-0.06); the mass ratio of the PLGA prepolymer, polyethylene glycol and diphenylmethane diisocyanate is (70-80):(30-40):(4-6).

[0015] As a limitation of the application, the preparation method of the attapulgite-chitosan modified crude natural cellulose fiber is as follows: Attapulgite is added to an aqueous sulfuric acid solution, ultrasonic activation is carried out at 60-70 DEG C and 150-200 W for 0.5-1 h, after the activation is completed, filtration is carried out, washing is carried out with deionized water, drying is carried out at 100-105 DEG C for 3-4 h, and then the attapulgite is added to deionized water, carboxymethyl chitosan, nano-silica sol and silane coupling agent KH-560 are added, stirring is carried out until uniform, and ultrasonic dispersion is carried out for 20-30 min, to obtain an attapulgite impregnation solution; Sodium hydroxide and urea are added to deionized water, stirring is carried out until uniform, to obtain a mixed solution, then the crude natural cellulose fiber is immersed in the mixed solution at 60-70 DEG C for 3-5 min, the pick-up rate is 75-80%, after the roller extrusion, the fiber is immersed in the attapulgite impregnation solution, and after immersion at 60-70 DEG C for 20-30 min, the fiber is taken out, the pick-up rate is 70-75%, and finally stepwise solidification is carried out, solidification is carried out at 80-90 DEG C for 40-50 s, solidification is carried out at 120-125 DEG C for 50-60 s, and solidification is carried out at 90-100 DEG C for 30-40 s, to obtain the modified crude natural cellulose fiber. After the attapulgite is activated by acid, the specific surface area is improved, the micrometer level pore channel constructs a main capillary wetness channel, the nano-silica sol selectively fills the mesopore of the attapulgite, a micropore-mesopore dual level wetness network is formed, and the wicking driving force is improved; the carboxyl group of the carboxymethyl chitosan is chelated and coordinated with the attapulgite aluminosilicate framework, the binding capacity between the fiber and the functional groups is significantly enhanced, the nano-silica sol is crosslinked between the fibers to form a Si-O-Si network, and the mechanical strength and the processing performance of the material are improved.

[0016] As the limitation of the application, the mass ratio of the attapulgite and the aqueous solution of sulfuric acid is (60-70):(80-100), the aqueous solution of sulfuric acid contains 5-10wt% of sulfuric acid; the mass ratio of the attapulgite, the carboxymethyl chitosan, the nano silicon sol and the silane coupling agent KH-550 is (60-70):(20-25):(40-50):(5-7); the mixed solution contains 3-5wt% of sodium hydroxide and 8-10wt% of urea.

[0017] As the limitation of the application, in the step 1, 6-10wt% of PLGA-PEG-MDI block copolymer ethanol solution is sprayed, the spraying amount is 15-20mL / kg, and when the opening mixing is carried out, the mass ratio of the activated viscose fiber and the zinc oxide-RAFT grafted polylactic acid fiber is (2-3):(4-5); in the step 2, the mass ratio of the polylactic acid granules and the PLGA-PEG-MDI block copolymer is (95-97):(3-5), the melting temperature is 180-190℃, the receiving distance is 15-18cm, and the density of the formed intermediate layer is 13-17g / m 2 ; in the step 3, the hydroentanglement pressure is 20-25bar, and the drying is gradient drying, 80-90℃ drying for 40-50s, 110-115℃ drying for 50-60s, and 90-100℃ drying for 30-40s.

[0018] A medical high-performance polylactic acid hydroentanglement composite nonwoven material is prepared by the preparation method in any one of the above.

[0019] Compared with the prior art, the beneficial effects of the application are reflected in: The polylactic acid fiber is grafted with RAFT and finished with quaternary ammonium salt chitosan coated nano zinc oxide modification, the moisture conducting function and the antibacterial performance of the polylactic acid fiber are enhanced, the PLGA-PEG-MDI block copolymer is designed, the interface compatibility of the polylactic acid fiber and the viscose fiber is enhanced, the crude natural cellulose fiber is modified, the moisture conducting function and the antibacterial performance are enhanced, the uniformity and consistency of the antibacterial performance are ensured through the common antibacterial modification of the fibers, the bacteria isolation effect is greater than 99.95%, and the top protection effect is achieved.

[0020] The application is designed by embedding the composite structure, the inner layer is prepared by using polylactic acid and viscose fiber as raw materials through the hydroentanglement composite process; the intermediate layer is formed by using polylactic acid through the melt blowing process; and the outer layer is formed by using the crude natural cellulose fiber for consolidation. Through the embedded layered distribution, the mechanical properties and the comfort of the material are improved; through the directional puncture reinforcement process, the three-dimensional interlocking network structure is formed, the mechanical properties of the material are enhanced; and the longitudinal moisture gradient of the fabric is formed, so that the product has the directional moisture conducting performance. DETAILED DESCRIPTION

[0021] The technical solutions in the embodiments of the present application will be clearly and completely described below. Obviously, the described embodiments are only some of the embodiments of the present application, rather than all the embodiments. The terms used in the embodiments are used for describing specific specific embodiments, rather than limiting the protection scope of the present application. The amount used in the embodiments is a laboratory small test, which can be scaled up proportionally. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative labor are within the protection scope of the present application.

[0022] Polylactic acid fiber (fineness: 1.2 dtex), viscose fiber (fineness: 1.5 dtex), polylactic acid granules (polymerization degree = 500 ± 50), coarse natural cellulose fiber (fineness: 2.5 dtex), nano zinc oxide (particle size: 50 ± 5 nm), polyethylene glycol (PEG-400, hydroxyl value: 60 mgKOH / g), attapulgite (particle size: 450 ± 50 nm), nano silicon sol (particle size: 15 ± 5 nm, SiO2content: ≥30wt%).

[0023] Embodiment 1: A preparation method of a medical high-performance polylactic acid spunlace composite nonwoven material, specifically: Step 1: 0.8g of silane coupling agent KH-550 was added to 200g of ethanol, after stirring at 30℃ and 350rpm for 15min, 30g of nano zinc oxide was added, the temperature was raised to 65℃, and the reaction was carried out under reflux at 350rpm for 3.5h. After the reaction was completed, it was filtered, washed with ethanol and acetone, and vacuum dried at 50℃ for 4h to obtain silane modified nano zinc oxide; Step 2: 75g of quaternary ammonium salt chitosan was added to 400mL of 1wt% acetic acid solution, stirred at 50℃ and 400rpm for 1.5h to obtain a quaternary ammonium salt chitosan solution, 60g of silane modified nano zinc oxide and 4g of polyethylene glycol were added to 75g of quaternary ammonium salt chitosan solution, reacted at 50℃ water bath and 250rpm for 3h, then centrifuged and freeze-dried for 4h to obtain quaternary ammonium salt chitosan coated nano zinc oxide; Step 3: 210mL of ethanol and 90mL of deionized water were mixed uniformly, then 150g of methacrylic acid sulfobetaine was added, stirred at 60℃ and 350rpm for 20min, then 3g of photoinitiator 2959 was added, deoxygenated by nitrogen bubbling for 15min to obtain a betaine ethanol dispersion, polylactic acid fiber was added to the betaine ethanol dispersion, immersed at 60℃ and 350rpm for 20min, then taken out, grafted under nitrogen protection and 365nm ultraviolet light irradiation for 90s, the irradiation intensity was 30mW / cm 2, and the grafted RAFT polylactic acid was immersed into an ethanol dispersion solution containing 0.1 wt% sodium carboxymethyl cellulose and 3 wt% quaternary ammonium salt chitosan-coated nano zinc oxide, taken out after vacuum-assisted immersion at -0.08 MPa for 15 min, and cured at 50 °C for 20 min and then at 70 °C for 20 min, to obtain a zinc oxide-RAFT grafted polylactic acid fiber; Step 4: Under nitrogen protection, 55 g of lactic acid, 15 g of glycolic acid, and 0.04 g of stannous octoate were added to a reaction kettle, and reacted at 170 °C for 3 h. After the reaction was completed, the temperature was lowered to 160 °C, and vacuum dehydration was performed at -0.08 MPa for 2 h to obtain a PLGA prepolymer. 70 g of the PLGA prepolymer was mixed with 30 g of polyethylene glycol, and 0.1 g of tetrabutyl titanate was added for catalysis. Polycondensation was performed at 135 °C and 0.08 MPa for 4 h. After the polycondensation was completed, the temperature was lowered to 80 °C, and 4 g of diphenylmethane diisocyanate was added. Reaction was performed under nitrogen protection for 1.5 h. After the reaction was completed, 0.05 g of phosphoric acid was added to terminate the reaction, to obtain a PLGA-PEG-MDI block copolymer; Step 5: 60 g of attapulgite was added to 80 g of 10 wt% sulfuric acid aqueous solution, and ultrasonically activated at 60 °C and 150 W for 1 h. After the activation was completed, filtration was performed, and the attapulgite was washed with deionized water. After being dried at 100 °C for 4 h, the attapulgite was added to 1 L of deionized water, and 20 g of carboxymethyl chitosan, 40 g of nano silica sol, and 5 g of silane coupling agent KH-560 were added. After being stirred uniformly, ultrasonic dispersion was performed for 30 min, to obtain an attapulgite impregnation solution; Step 6: Sodium hydroxide and urea were added to deionized water, and stirred uniformly, to obtain a mixed solution containing 3 wt% sodium hydroxide and 8 wt% urea. Subsequently, the crude natural cellulose fiber was immersed into the mixed solution at 60 °C for 5 min, with a pick-up rate of 80%. After being extruded by a roller, the crude natural cellulose fiber was immersed into the attapulgite impregnation solution. After being immersed at 60 °C for 30 min, the crude natural cellulose fiber was taken out, with a pick-up rate of 75%. Finally, stepwise curing was performed at 80 °C for 40 s, at 120 °C for 50 s, and at 90 °C for 30 s, to obtain an attapulgite-chitosan modified crude natural cellulose fiber; Step 7: Put the viscose fiber into the reaction chamber of the plasma activation device, and pass in a mixture of helium and oxygen (volume ratio 9:1) with a power setting of 180W. Activate for 5 minutes, then take out, spray 6wt% PLGA-PEG-MDI block copolymer ethanol solution, spray amount is 15mL / kg, after spraying, open and mix with zinc oxide-RAFT grafted polylactic acid fiber at a mass ratio of 3:5, the opening roller speed is 800rpm, the opening time is 8min, after opening, cross-lay, when laying, use airflow assisted directional transportation with air speed of 0.8m / s and angle of 15°, mix polylactic acid granules and PLGA-PEG-MDI block copolymer at a mass ratio of 95:5, then melt blow onto the laid web at 185℃, the receiving distance is 18cm, the formed intermediate layer is 15g / m 2 , after melt blowing, fix with 30bar pressure pre-spunlace, then cover with attapulgite-chitosan modified coarse natural cellulose fiber, reinforce with 20bar low pressure spunlace, dry at 80℃ for 40s, dry at 110℃ for 50s, dry at 90℃ for 30s, wind up, to obtain a medical high-performance polylactic acid spunlace composite nonwoven material.

[0024] Example 2: A method for preparing a medical high-performance polylactic acid spunlace composite nonwoven material, specifically: Step 1: Add 0.9g silane coupling agent KH-550 to 200g ethanol, stir at 30℃ and 350rpm for 15min, then add 30g nano zinc oxide, heat to 65℃, reflux at 350rpm for 3.5h, after reaction, filter, wash with ethanol and acetone, vacuum dry at 50℃ for 4h, to obtain silane modified nano zinc oxide; Step 2: Add 75g quaternary ammonium salt chitosan to 400mL 1wt% acetic acid solution, stir at 50℃ and 400rpm for 1.5h, to obtain quaternary ammonium salt chitosan solution, add 65g silane modified nano zinc oxide and 4g polyethylene glycol to 75g quaternary ammonium salt chitosan solution, react at 50℃ water bath and 250rpm for 3h, after reaction, centrifugal separation, freeze-drying for 4h, to obtain quaternary ammonium salt chitosan coated nano zinc oxide; Step 3: Mix 210mL ethanol and 90mL deionized water uniformly, then add 155g methacrylic acid sulfobetaine, stir at 60℃ and 350rpm for 20min, then add 3g photoinitiator 2959, deoxygenate with nitrogen bubbling for 15min, to obtain betaine ethanol dispersion, add polylactic acid fiber to the betaine ethanol dispersion, immerse at 60℃ and 350rpm for 20min, then take out, irradiate under nitrogen protection at 365nm ultraviolet light for 90s, the irradiation intensity is 30mW / cm 2, and the grafted RAFT polylactic acid was immersed into an ethanol dispersion solution containing 0.1 wt% sodium carboxymethyl cellulose and 3 wt% quaternary ammonium salt chitosan-coated nano zinc oxide, taken out after vacuum-assisted immersion at -0.08 MPa for 15 min, and cured at 50 °C for 20 min and then at 70 °C for 20 min, to obtain zinc oxide-RAFT grafted polylactic acid fibers; Step 4: Under nitrogen protection, 55 g of lactic acid, 15 g of glycolic acid, and 0.04 g of stannous octoate were added to a reaction kettle, and reacted at 170 °C for 3 h. After the reaction was completed, the temperature was lowered to 160 °C, and vacuum dehydration was performed at -0.08 MPa for 2 h to obtain a PLGA prepolymer. 70 g of the PLGA prepolymer was mixed with 30 g of polyethylene glycol, and 0.1 g of tetrabutyl titanate was added for catalysis. Polycondensation was performed at 135 °C and 0.08 MPa for 4 h. After the polycondensation was completed, the temperature was lowered to 80 °C, and 4 g of diphenylmethane diisocyanate was added. Reaction was performed under nitrogen protection for 1.5 h. After the reaction was completed, 0.05 g of phosphoric acid was added to terminate the reaction, to obtain a PLGA-PEG-MDI block copolymer; Step 5: 65 g of attapulgite was added to 80 g of 10 wt% sulfuric acid aqueous solution, and ultrasonically activated at 60 °C and 150 W for 1 h. After the activation was completed, filtration was performed, and the product was washed with deionized water. After drying at 100 °C for 4 h, the product was added to 1 L of deionized water, and 20 g of carboxymethyl chitosan, 40 g of nano-silica sol, and 5 g of silane coupling agent KH-560 were added. After stirring and uniform mixing, ultrasonic dispersion was performed for 30 min, to obtain an attapulgite impregnation solution; Step 6: Sodium hydroxide and urea were added to deionized water, and stirred to obtain a mixed solution containing 3 wt% sodium hydroxide and 8 wt% urea. Then, the crude natural cellulose fibers were immersed in the mixed solution at 60 °C for 5 min, with a pick-up rate of 80%. After the rolling extrusion, the fibers were immersed in the attapulgite impregnation solution, taken out after immersion at 60 °C for 30 min, with a pick-up rate of 75%. Finally, stepwise curing was performed at 80 °C for 40 s, at 120 °C for 50 s, and at 90 °C for 30 s, to obtain attapulgite-chitosan modified crude natural cellulose fibers; Step 7: Put the viscose fiber into the reaction chamber of the plasma activation device, and pass in a mixture of helium and oxygen (volume ratio 9:1) with a power setting of 180W. After 5 minutes of activation, take it out, spray 8wt% PLGA-PEG-MDI block copolymer ethanol solution, and the spraying amount is 15mL / kg. After spraying, mix it with the zinc oxide-RAFT grafted polylactic acid fiber at a mass ratio of 3:6, and the opening roller speed is 800rpm. The opening time is 8 minutes. After opening, cross-lay the web with air-assisted directional transport at a wind speed of 0.8m / s and an angle of 15°. Mix the polylactic acid granules and PLGA-PEG-MDI block copolymer at a mass ratio of 95:5, and melt-blow them onto the laid web at 185℃, with a receiving distance of 18cm. The intermediate layer formed is 15g / m 2 After melt-blowing, fix it with 30bar pressure pre-spunlace, then lay the attapulgite-chitosan modified coarse natural cellulose fiber, and reinforce it with 20bar low-pressure spunlace. Dry it at 80℃ for 40s, 110℃ for 50s, and 90℃ for 30s. Wind it up to get a medical high-performance polylactic acid spunlace composite nonwoven material.

[0025] Example 3: A method for preparing a medical high-performance polylactic acid spunlace composite nonwoven material, specifically: Step 1: Add 1.0g of silane coupling agent KH-550 to 200g of ethanol. After stirring at 30℃ and 350rpm for 15 minutes, add 30g of nano zinc oxide. Increase the temperature to 65℃ and reflux at 350rpm for 3.5 hours. After the reaction is complete, filter and wash with ethanol and acetone. Dry at 50℃ under vacuum for 4 hours to obtain silane-modified nano zinc oxide. Step 2: Add 75g of quaternary ammonium salt chitosan to 400mL of 1wt% acetic acid solution. Stir at 50℃ and 400rpm for 1.5 hours to obtain a quaternary ammonium salt chitosan solution. Add 70g of silane-modified nano zinc oxide and 4g of polyethylene glycol to the 75g of quaternary ammonium salt chitosan solution. React at 50℃ water bath and 250rpm for 3 hours. After the reaction is complete, centrifuge and freeze-dry for 4 hours to obtain quaternary ammonium salt chitosan-coated nano zinc oxide. Step 3: Mix 210mL of ethanol and 90mL of deionized water evenly, then add 160g of methacrylic acid sulfobetaine. Stir at 60℃ and 350rpm for 20 minutes, then add 3g of photoinitiator 2959. Bubble nitrogen to remove oxygen for 15 minutes to obtain a betaine ethanol dispersion. Add polylactic acid fiber to the betaine ethanol dispersion and immerse at 60℃ and 350rpm for 20 minutes. Take it out and irradiate it under nitrogen protection at 365nm ultraviolet light for 90s with an irradiation intensity of 30mW / cm 2, and the grafted RAFT polylactic acid was immersed into an ethanol dispersion solution containing 0.1 wt% sodium carboxymethyl cellulose and 3 wt% quaternary ammonium salt chitosan-coated nano zinc oxide, taken out after vacuum-assisted immersion at -0.08 MPa for 15 min, and cured at 50 °C for 20 min and then at 70 °C for 20 min, to obtain a zinc oxide-RAFT grafted polylactic acid fiber; Step 4: Under nitrogen protection, 55 g of lactic acid, 15 g of glycolic acid, and 0.04 g of stannous octoate were added to a reaction kettle, and reacted at 170 °C for 3 h. After the reaction was completed, the temperature was lowered to 160 °C, and vacuum dehydration was performed at -0.08 MPa for 2 h to obtain a PLGA prepolymer. 70 g of the PLGA prepolymer was mixed with 30 g of polyethylene glycol, and 0.1 g of tetrabutyl titanate was added for catalysis. Polycondensation was performed at 135 °C and 0.08 MPa for 4 h. After the polycondensation was completed, the temperature was lowered to 80 °C, and 4 g of diphenylmethane diisocyanate was added. Reaction was performed under nitrogen protection for 1.5 h. After the reaction was completed, 0.05 g of phosphoric acid was added to terminate the reaction, to obtain a PLGA-PEG-MDI block copolymer; Step 5: 70 g of attapulgite was added to 80 g of 10 wt% sulfuric acid aqueous solution, and ultrasonically activated at 60 °C and 150 W for 1 h. After the activation was completed, filtration was performed, and the attapulgite was washed with deionized water. After drying at 100 °C for 4 h, the attapulgite was added to 1 L of deionized water, and 20 g of carboxymethyl chitosan, 40 g of nano-silica sol, and 5 g of silane coupling agent KH-560 were added. After stirring and uniform mixing, ultrasonic dispersion was performed for 30 min to obtain an attapulgite impregnation solution; Step 6: Sodium hydroxide and urea were added to deionized water, and stirred to obtain a mixed solution containing 3 wt% sodium hydroxide and 8 wt% urea. Then, the crude natural cellulose fiber was immersed in the mixed solution at 60 °C for 5 min, with a pick-up rate of 80%. After the rolling extrusion, the crude natural cellulose fiber was immersed in the attapulgite impregnation solution, taken out after immersion at 60 °C for 30 min, with a pick-up rate of 75%. Finally, stepwise curing was performed at 80 °C for 40 s, at 120 °C for 50 s, and at 90 °C for 30 s, to obtain attapulgite-chitosan modified crude natural cellulose fiber; Step 7: Put the viscose fiber into the reaction chamber of the plasma activation device, and pass in a mixture of helium and oxygen (volume ratio 9:1) with a power setting of 180W. Activate for 5 minutes, then take out, spray 10wt% PLGA-PEG-MDI block copolymer ethanol solution, spray amount is 15mL / kg, after spraying, mix with zinc oxide-RAFT grafted polylactic acid fiber according to mass ratio 3:7, the opening roller speed is 800rpm, the opening time is 8min, after opening, cross-laying is adopted, the airflow assisted directional conveying is adopted with air speed of 0.8m / s and angle of 15°, the polylactic acid granules and the PLGA-PEG-MDI block copolymer are mixed according to a mass ratio of 95:5, and then sprayed onto the laid web at 185°C, with a receiving distance of 18cm, to form an intermediate layer of 15g / m 2 , after melt blowing, 30bar pressure is used for pre-water jetting fixation, then attapulgite-chitosan modified coarse natural cellulose fiber is laid, 20bar low pressure water jetting is used for reinforcement, 80°C drying for 40s, 110°C drying for 50s, 90°C drying for 30s, winding, to obtain a medical high-performance polylactic acid water jetting composite nonwoven material.

[0026] Based on Example 1, the following control experiments are carried out, specifically Comparative Example 1, Comparative Example 2, Comparative Example 3, as follows: Comparative Example 1: This comparative example relates to a method for preparing a medical high-performance polylactic acid water jetting composite nonwoven material, which is different from Example 1 in that no PLGA-PEG-MDI block copolymer is added, specifically: Step 1: Add 0.8g silane coupling agent KH-550 to 200g ethanol, stir at 30°C and 350rpm for 15min, then add 30g nano zinc oxide, heat to 65°C, and reflux at 350rpm for 3.5h, after the reaction is completed, filter, wash with ethanol and acetone, and vacuum dry at 50°C for 4h to obtain silane modified nano zinc oxide; Step 2: Add 75g quaternary ammonium salt chitosan to 400mL 1wt% acetic acid solution, stir at 50°C and 400rpm for 1.5h to obtain a quaternary ammonium salt chitosan solution, add 60g silane modified nano zinc oxide and 4g polyethylene glycol to 75g quaternary ammonium salt chitosan solution, react at 50°C water bath and 250rpm for 3h, after the reaction is completed, centrifugal separation, and freeze-drying for 4h to obtain quaternary ammonium salt chitosan coated nano zinc oxide; Step 3: 210 mL of ethanol and 90 mL of deionized water were mixed uniformly, and then 150 g of methacrylic acid sulfobetaine was added. After stirring at 60 ℃ and 350 rpm for 20 min, 3 g of photoinitiator 2959 was added. Oxygen was removed by nitrogen bubbling for 15 min to obtain a betaine ethanol dispersion. The polylactic acid fiber was added to the betaine ethanol dispersion, and after immersion at 60 ℃ and 350 rpm for 20 min, it was taken out and irradiated with 365 nm ultraviolet light for 90 s under nitrogen protection, with an irradiation intensity of 30 mW / cm 2 , to obtain grafted RAFT polylactic acid. The grafted RAFT polylactic acid was immersed in an ethanol dispersion containing 0.1 wt% carboxymethyl cellulose sodium and 3 wt% quaternary ammonium salt chitosan-coated nano-zinc oxide. After vacuum-assisted immersion at -0.08 MPa for 15 min, it was taken out, solidified at 50 ℃ for 20 min, and then solidified at 70 ℃ for 20 min to obtain zinc oxide-RAFT grafted polylactic acid fiber; Step 4: 60 g of attapulgite was added to 80 g of 10 wt% sulfuric acid aqueous solution, and ultrasonic activation was performed at 60 ℃ and 150 W for 1 h. After activation, filtration was performed, and deionized water was used for washing. After drying at 100 ℃ for 4 h, it was added to 1 L of deionized water, and 20 g of carboxymethyl chitosan, 40 g of nano-silica sol, and 5 g of silane coupling agent KH-560 were added. After stirring and ultrasonic dispersion for 30 min, an attapulgite immersion solution was obtained. Step 5: Sodium hydroxide and urea were added to deionized water, and stirring was performed to obtain a mixed solution containing 3 wt% sodium hydroxide and 8 wt% urea. Then, the crude natural cellulose fiber was immersed in the mixed solution at 60 ℃ for 5 min, with a pick-up rate of 80%. After roller extrusion, it was immersed in the attapulgite immersion solution at 60 ℃ for 30 min, and then taken out, with a pick-up rate of 75%. Finally, stepwise solidification was performed at 80 ℃ for 40 s, at 120 ℃ for 50 s, and at 90 ℃ for 30 s to obtain attapulgite-chitosan modified crude natural cellulose fiber. Step 6: The viscose fiber was placed in the reaction chamber of the plasma activation equipment, and a mixed gas of helium and oxygen (volume ratio 9:1) was introduced. The power was set to 180 W, and activation was performed for 5 min. Then, the zinc oxide-RAFT grafted polylactic acid fiber was opened and mixed with the zinc oxide-RAFT grafted polylactic acid fiber at a mass ratio of 3:5. The opening roller rotation speed was 800 rpm, and the opening time was 8 min. After opening, cross-laying was performed. Airflow-assisted directional conveying was adopted during laying, with an air speed of 0.8 m / s and an angle of 15°. Polylactic acid pellets were melt-blown onto the laid layer at 185 ℃, with a receiving distance of 18 cm. The intermediate layer formed had a weight of 15 g / m 2 . After melt-blowing, it was fixed by water jetting at 30 bar. Then, the attapulgite-chitosan modified crude natural cellulose fiber was laid, and water jetting was performed at a low pressure of 20 bar. Drying was performed at 80 ℃ for 40 s, at 110 ℃ for 50 s, and at 90 ℃ for 30 s. Finally, winding was performed to obtain a medical high-performance polylactic acid water-jet composite non-woven material.

[0027] Comparative Example 2: This comparative example relates to a method for preparing a medical high-performance polylactic acid spunlace composite nonwoven material, which differs from Example 1 in that the polylactic acid fibers are not modified, specifically: Step 1: Under nitrogen protection, 55 g of lactic acid, 15 g of glycolic acid and 0.04 g of stannous octoate were added to a reaction kettle, and reacted at 170°C for 3 h. After the reaction was completed, the temperature was lowered to 160°C, and dehydrated under a vacuum of -0.08 MPa for 2 h to obtain a PLGA prepolymer. 70 g of the PLGA prepolymer was mixed with 30 g of polyethylene glycol, and 0.1 g of tetrabutyl titanate was added for catalysis. The polycondensation was carried out at 135°C and 0.08 MPa for 4 h. After the polycondensation was completed, the temperature was lowered to 80°C, and 4 g of diphenylmethane diisocyanate was added. The reaction was carried out under nitrogen protection for 1.5 h. After the reaction was completed, 0.05 g of phosphoric acid was added to terminate the reaction, and a PLGA-PEG-MDI block copolymer was obtained; Step 2: 60 g of attapulgite was added to 80 g of 10 wt% sulfuric acid aqueous solution, and was activated under ultrasonic at 60°C and 150 W for 1 h. After the activation was completed, it was filtered, washed with deionized water, and dried at 100°C for 4 h. Then it was added to 1 L of deionized water, and 20 g of carboxymethyl chitosan, 40 g of nano-silica sol and 5 g of silane coupling agent KH-560 were added. After being stirred uniformly, it was ultrasonically dispersed for 30 min to obtain an attapulgite impregnating solution; Step 3: Sodium hydroxide and urea were added to deionized water, and stirred uniformly to obtain a mixed solution containing 3 wt% sodium hydroxide and 8 wt% urea. Then the crude natural cellulose fibers were immersed in the mixed solution at 60°C for 5 min, and the pick-up rate was 80%. After being extruded by a roller, the fibers were immersed in the attapulgite impregnating solution at 60°C for 30 min, and then taken out, and the pick-up rate was 75%. Finally, the fibers were stepwise solidified at 80°C for 40 s, at 120°C for 50 s, and at 90°C for 30 s to obtain attapulgite-chitosan modified crude natural cellulose fibers; Step 4: The viscose fibers were placed in the reaction chamber of a plasma activation device, and a mixed gas of helium and oxygen (volume ratio 9:1) was introduced. The power was set to 180 W, and the fibers were activated for 5 min and then taken out. A 6 wt% PLGA-PEG-MDI block copolymer ethanol solution was sprayed, and the spraying amount was 15 mL / kg. After the spraying was completed, the polylactic acid fibers were opened and mixed with the polylactic acid fibers at a mass ratio of 3:5. The opening roller rotation speed was 800 rpm, and the opening time was 8 min. After the opening was completed, the fibers were cross-laid. Airflow assisted directional conveying was adopted during the laying, and the air speed was 0.8 m / s, and the angle was 15°. The polylactic acid pellets and the PLGA-PEG-MDI block copolymer were mixed at a mass ratio of 95:5, and then were melt-blown onto the laid fibers at 185°C. The receiving distance was 18 cm, and the mass per unit area of the intermediate layer was 15 g / m 2, 30 bar pressure pre-water jetting fixation after melt blowing, then palygorskite-chitosan modified coarse natural cellulose fiber is laid, 20 bar low pressure water jetting reinforcement, 80 °C drying for 40 s, 110 °C drying for 50 s, 90 °C drying for 30 s, winding, to obtain a medical high-performance polylactic acid water jetting composite nonwoven material.

[0028] Comparative Example 3: This comparative example relates to a method for preparing a medical high-performance polylactic acid water jetting composite nonwoven material, which is different from Example 1 in that the coarse natural cellulose fiber is not modified, specifically: Step 1: 0.8 g of silane coupling agent KH-550 is added to 200 g of ethanol, after stirring at 30 °C and 350 rpm for 15 min, 30 g of nano zinc oxide is added, the temperature is raised to 65 °C, and the reaction is carried out under reflux at 350 rpm for 3.5 h. After the reaction is completed, filter, wash with ethanol and acetone, and vacuum dry at 50 °C for 4 h to obtain silane-modified nano zinc oxide; Step 2: 75 g of quaternary ammonium salt chitosan is added to 400 mL of 1 wt% acetic acid solution, stirred at 50 °C and 400 rpm for 1.5 h to obtain a quaternary ammonium salt chitosan solution, 60 g of silane-modified nano zinc oxide and 4 g of polyethylene glycol are added to the 75 g of quaternary ammonium salt chitosan solution, and the reaction is carried out at 50 °C water bath and 250 rpm for 3 h. After the reaction is completed, centrifugal separation, and freeze-drying for 4 h, quaternary ammonium salt chitosan-coated nano zinc oxide is obtained; Step 3: 210 mL of ethanol and 90 mL of deionized water are mixed uniformly, then 150 g of methacrylic acid sulfobetaine is added, stirred at 60 °C and 350 rpm for 20 min, then 3 g of photoinitiator 2959 is added, deoxygenated by nitrogen bubbling for 15 min, to obtain a betaine ethanol dispersion, polylactic acid fibers are added to the betaine ethanol dispersion, immersed at 60 °C and 350 rpm for 20 min, then taken out, irradiated under nitrogen protection at 365 nm ultraviolet light for 90 s, and the irradiation intensity is 30 mW / cm 2 , to obtain grafted RAFT polylactic acid, the grafted RAFT polylactic acid is immersed in an ethanol dispersion containing 0.1 wt% carboxymethyl cellulose sodium and 3 wt% quaternary ammonium salt chitosan-coated nano zinc oxide, vacuum assisted immersion at -0.08 MPa for 15 min, then taken out, solidified at 50 °C for 20 min, then solidified at 70 °C for 20 min, to obtain zinc oxide-RAFT grafted polylactic acid fibers; Step 4: 55 g of lactic acid, 15 g of glycolic acid and 0.04 g of stannous octoate were added into a reaction kettle under nitrogen protection, and reacted at 170℃ for 3 h. After the reaction was completed, the temperature was lowered to 160℃, and vacuum dehydration was performed at -0.08 MPa for 2 h to obtain a PLGA prepolymer. 70 g of the PLGA prepolymer was mixed with 30 g of polyethylene glycol, 0.1 g of tetrabutyl titanate was added as a catalyst, and polycondensation was performed at 135℃ and 0.08 MPa for 4 h. After the polycondensation was completed, the temperature was lowered to 80℃, 4 g of diphenylmethane diisocyanate was added, and the reaction was performed under nitrogen protection for 1.5 h. After the reaction was completed, 0.05 g of phosphoric acid was added to terminate the reaction, and a PLGA-PEG-MDI block copolymer was obtained; Step 5: The viscose fibers were placed in the reaction chamber of a plasma activation device, and a mixture of helium and oxygen (volume ratio 9:1) was introduced. The power was set to 180 W, and the activation was performed for 5 min. Then, 6 wt% of a PLGA-PEG-MDI block copolymer ethanol solution was sprayed at a spraying amount of 15 mL / kg. After the spraying was completed, the zinc oxide-RAFT grafted polylactic acid fibers were mixed with the viscose fibers at a mass ratio of 3:5. The opening roller rotation speed was 800 rpm, and the opening time was 8 min. After the opening was completed, cross-laying was performed. During the laying, airflow assisted directional conveying was adopted at an air speed of 0.8 m / s and an angle of 15°. The polylactic acid granules and the PLGA-PEG-MDI block copolymer were mixed at a mass ratio of 95:5, and then were melt-blown onto the laid web at 185℃. The receiving distance was 18 cm, and the intermediate layer was formed at a weight of 15 g / m 2 After the melt-blowing, 30 bar pressure was used for water jetting to fix the fibers, and then the coarse natural cellulose was laid on. 20 bar low pressure water jetting was used for reinforcement, and then the material was dried at 80℃ for 40 s, at 110℃ for 50 s, and at 90℃ for 30 s. Finally, the material was wound to obtain a medical high-performance polylactic acid water jetting composite nonwoven material.

[0029] Detection experiment: The medical high-performance polylactic acid water jetting composite nonwoven material samples were prepared according to the examples and the comparative examples, respectively, and the following tests were performed.

[0030] Antibacterial performance test: The antibacterial performance of the water jetting composite nonwoven material samples was tested according to the Evaluation of Antibacterial Properties of Textiles Part 3: Oscillation Method (GB / T 20944.3-2008). The test bacteria were selected as Staphylococcus aureus, Escherichia coli and Candida albicans. The bacteria were diluted to 10 6The CFU / mL bacterial suspension was prepared, and the spunlace composite nonwoven material sample was cut into a size of 5 cm x 5 cm and sterilized at 120 DEG C for 15 min, then inoculated into a conical flask, and 1 mL of the bacterial suspension was inoculated on the surface. After 18 h of culture at 37 DEG C and 200 rpm, the sample was taken out, eluted with 100 mL of neutralizing solution (0.5 wt% sodium thiosulfate and 3 wt% Tween-80), mixed with 9 mL of PBS, diluted by 10 times, and 1 mL of the diluted solution was added to an agar culture plate. After 24 h of culture at 37 DEG C, the colony count was performed, and the antibacterial rate of the sample was calculated.

[0031] Directional moisture transfer test: According to the "Textiles - Assessment of the moisture management performance - Part 2: Dynamic moisture transfer method" (GB / T 21655.2-2009), three 9 cm x 9 cm spunlace composite nonwoven material samples were prepared, and the front and back of each material were tested. The side containing polylactic acid fibers and viscose fibers was tested as the surface layer, and the side containing coarse natural cellulose was tested as the bottom layer. The material was placed on the sensor of a M290 liquid moisture tester (Xilaiyatai), and the tester was started. 0.2 g of test solution was added to the test surface within 20 s, and the one-way transfer index was calculated.

[0032] 180-day compost degradation test: 50 g of the spunlace composite nonwoven material sample was crushed to a particle size of ≤2 mm, and the total organic carbon content was determined. Then, waste compost (meeting the requirements of ISO 17556) was prepared, and the moisture content was adjusted to 50%, the pH was adjusted to 7.0, and the volatile solid content was adjusted to 30%. The crushed particles and the adjusted compost were mixed uniformly at a dry weight ratio of 1:6, and then were placed in a reactor. After sealing, 0.1 L / min of oxygen was introduced into one end, and the exhaust pipe at the other end was inserted into a 0.4 mol / L sodium hydroxide solution. The sodium hydroxide solution was replaced every 24 h, and the reactor was shaken twice a week to prevent hardening. Fresh compost was added every month to maintain microbial activity, and the total weight was 5%. The release amount of carbon dioxide in the reactor was determined after 180 days. The same test was performed on the control group without adding the spunlace composite nonwoven material particles, and the biodegradation rate of the spunlace composite nonwoven material sample was calculated.

[0033]

[0034] Conclusion: According to the test data, the antibacterial rate of Staphylococcus aureus / Escherichia coli, the one-way moisture transfer index, and the biodegradation rate of the 180-day compost test of the medical high-performance polylactic acid spunlace composite nonwoven material sample prepared in the example are all better than those of the comparative example. The medical high-performance polylactic acid spunlace composite nonwoven material provided by the present application has good antibacterial performance, one-way moisture transfer performance, and degradation, and the composite nonwoven material can fully meet the demand of high-quality medical protective materials.

[0035] It will be apparent to those skilled in the art that the application is not limited to the details of the above-exemplified embodiments and that the present application can be implemented in other particular forms without departing from the spirit or essential characteristics of the present application. The embodiments should therefore be considered in all respects as illustrative and not restrictive, the scope of the application being indicated by the appended claims rather than by the above description, and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein.

Claims

1. A method of making a medical high performance polylactic acid hydroentangled composite nonwoven material, characterized by: Specifically: Step 1: after the viscose fiber is plasma activated, spray PLGA-PEG-MDI block copolymer ethanol solution, then mix with zinc oxide-RAFT grafted polylactic acid fiber and open, cross-lay; Step 2: after mixing polylactic acid particles with PLGA-PEG-MDI block copolymer, melt blowing to the lay formed in step 1, form the intermediate layer, then pre-water jetting fixation; Step 3: after the attapulgite-chitosan modified coarse natural cellulose fiber is laid on the pre-water jetting fixed intermediate layer, water jetting reinforcement, drying and winding, the medical high-performance polylactic acid water jetting composite nonwoven material is obtained.

2. The preparation method of a medical high-performance polylactic acid spunlace composite nonwoven material according to claim 1, characterized in that: In step 1, the preparation method of zinc oxide-RAFT grafted polylactic acid fiber is: After mixing ethanol and deionized water evenly, add methacrylic acid sulfobetaine, after stirring at 60-70℃, 300-400rpm for 20-25min, add photoinitiator 2959, bubble nitrogen to remove oxygen for 10-15min, get betaine ethanol dispersion, add polylactic acid fiber into betaine ethanol dispersion, after dipping at 60-70℃, 300-400rpm for 15-20min, take out, irradiate under nitrogen protection, 365nm ultraviolet light for 60-120s, irradiation intensity is 25-35mW / cm 2 , get grafting RAFT polylactic acid, dip grafting RAFT polylactic acid into ethanol dispersion containing carboxymethyl cellulose sodium and quaternary ammonium salt chitosan coated nano zinc oxide, take out after vacuum assisted dipping at (-0.08)-(-0.09)MPa for 15-20min, solidify at 50-60℃ for 20-30min, then solidify at 60-70℃ for 20-30min, get zinc oxide-RAFT grafting polylactic acid fiber.

3. The preparation method of a medical high-performance polylactic acid spunlace composite nonwoven material according to claim 2, characterized in that: In betaine ethanol dispersion, the volume ratio of ethanol and deionized water is (7-8):(2-3), and the concentration of methacrylic acid sulfobetaine is 0.5-0.6g / mL; In ethanol dispersion, 0.1-0.2wt% sodium carboxymethyl cellulose and 3-5wt% quaternary ammonium salt chitosan coated nano zinc oxide are contained.

4. The preparation method of a medical high-performance polylactic acid spunlace composite nonwoven material according to claim 2, characterized in that: The preparation method of quaternary ammonium salt chitosan coated nano zinc oxide is: Silane coupling agent KH-550 is added to ethanol, after stirring at 25-30℃, 300-400rpm for 15-20min, nano zinc oxide is added, the temperature is raised to 65-70℃, and the reaction is carried out under reflux at 300-400rpm for 3-4h, after the reaction is completed, filtration is carried out, washing is carried out with ethanol and acetone, and vacuum drying is carried out at 50-60℃ for 3-4h, to obtain silane modified nano zinc oxide; Quaternary ammonium salt chitosan is added to acetic acid solution, stirring is carried out at 40-50℃, 400-500rpm for 1-2h, to obtain quaternary ammonium salt chitosan solution, silane modified nano zinc oxide and polyethylene glycol are added to the quaternary ammonium salt chitosan solution, reaction is carried out under water bath at 50-60℃, 200-300rpm for 2-3h, after the reaction is completed, centrifugal separation is carried out, and freeze drying is carried out for 3-4h, to obtain quaternary ammonium salt chitosan coated nano zinc oxide.

5. The preparation method of a medical high-performance polylactic acid spunlace composite nonwoven material according to claim 1, characterized in that: The preparation method of PLGA-PEG-MDI block copolymer is: Under the protection of nitrogen, lactic acid, hydroxyacetic acid and stannous octoate are mixed, the reaction is carried out at 160-170℃ for 3-4h, after the reaction is completed, the temperature is lowered to 150-160℃, vacuum dehydration is carried out at (-0.08)-(-0.09)MPa for 2-3h, to obtain PLGA prepolymer, the PLGA prepolymer is mixed with polyethylene glycol, and tetrabutyl titanate is added for catalysis, polycondensation is carried out at 130-140℃, 0.08-0.1MPa for 3-5h, after the polycondensation is completed, the temperature is lowered to 80-90℃, diphenylmethane diisocyanate is added, reaction is carried out under the protection of nitrogen for 1-2h, after the reaction is completed, phosphoric acid is added to terminate the reaction, to obtain PLGA-PEG-MDI block copolymer.

6. The preparation method of a medical high-performance polylactic acid spunlace composite nonwoven material according to claim 5, characterized in that: The mass ratio of lactic acid, hydroxyacetic acid and stannous octoate is (55-65):(15-25):(0.04-0.06); the mass ratio of PLGA prepolymer, polyethylene glycol and diphenylmethane diisocyanate is (70-80):(30-40):(4-6).

7. The method for preparing a medical high-performance polylactic acid spunlace composite nonwoven material according to claim 6, characterized in that: The preparation method of attapulgite-chitosan modified coarse natural cellulose fiber is: The attapulgite is added to the aqueous sulfuric acid solution, ultrasonically activated at 60-70 DEG C for 0.5-1 h, filtered after activation, washed with deionized water, dried at 100-105 DEG C for 3-4 h, then added to deionized water, added with carboxymethyl chitosan, nano-silica sol and silane coupling agent KH-560, stirred uniformly, ultrasonically dispersed for 20-30 min, to obtain the attapulgite impregnation solution; The sodium hydroxide and urea are added to the deionized water, stirred uniformly to obtain a mixed solution, then the crude natural cellulose fibers are immersed in the mixed solution at 60-70 DEG C for 3-5 min, the pick-up rate is 75-80%, after roller extrusion, the fibers are immersed in the attapulgite impregnation solution, taken out after immersion at 60-70 DEG C for 20-30 min, the pick-up rate is 70-75%, finally stepwise solidified, solidified at 80-90 DEG C for 40-50 s, at 120-125 DEG C for 50-60 s, at 90-100 DEG C for 30-40 s, to obtain the modified crude natural cellulose fibers.

8. The method for preparing a high-performance medical polylactic acid spunlace composite nonwoven material according to claim 7, characterized in that: The mass ratio of attapulgite to aqueous sulfuric acid solution is (60-70):(80-100), the aqueous sulfuric acid solution contains 5-10 wt% sulfuric acid; the mass ratio of attapulgite to carboxymethyl chitosan to nano-silica sol to silane coupling agent KH-550 is (60-70):(20-25):(40-50):(5-7); the mixed solution contains 3-5 wt% sodium hydroxide and 8-10 wt% urea.

9. The preparation method of a medical high-performance polylactic acid spunlace composite nonwoven material according to claim 1, characterized in that: In step 1, a 6-10 wt% PLGA-PEG-MDI block copolymer ethanol solution is sprayed, the spraying amount is 15-20 mL / kg, and the mass ratio of activated viscose fiber to zinc oxide-RAFT grafted polylactic acid fiber is (2-3):(4-5) during mixing; in step 2, the mass ratio of polylactic acid granules to PLGA-PEG-MDI block copolymer is (95-97):(3-5), the melting temperature is 180-190℃, the receiving distance is 15-18 cm, and the density of the formed intermediate layer is 13-17 g / m 2 ; in step 3, the water jet pressure is 20-25 bar, and the drying is gradient drying, 80-90℃ for 40-50 s, 110-115℃ for 50-60 s, and 90-100℃ for 30-40 s. 10.A medical high-performance polylactic acid spunlace composite nonwoven material prepared by the method of any one of claims 1-9.

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