High-filtration polyethylene non-woven material and preparation method thereof

Abstract

The invention provides a high-filtration polyethylene non-woven material and a preparation method thereof, the high-filtration polyethylene non-woven material comprises a spunbond layer and a melt-blown layer, the melt-blown layer is formed by melt-blowing spinning of first high melt index polyethylene and second high melt index polyethylene, the melt indexes of the first high-melt-index polyethylene and the second high-melt-index polyethylene are both greater than or equal to 200g / 10min, and the melt indexes of the first high-melt-index polyethylene and the second high-melt-index polyethylene are different. The melt-blown layer is prepared from the high-melt-index polyethylene through melt-blown spinning, the two kinds of high-melt-index polyethylene with different melt indexes are adopted, the crystallization rate and fluidity of the polyethylene with the different melt indexes can be utilized, and the effect of binding molecules in an amorphous area to induce molecular chain orientation in the crystallization process is achieved; therefore, the fiber reinforcement effect is improved, and the problem of low mechanical strength of melt-blown fibers is effectively solved.

Description

Technical Field

[0001] The invention relates to the field of nonwoven materials, and in particular to a high-filtration polyethylene nonwoven material and a preparation method thereof. Background Art

[0002] Domestic medical protective materials mostly use meltblown polypropylene microfiber nonwoven materials as the core filter layer. However, polypropylene meltblown cloth needs to be sterilized with ethylene oxide, so the sterilization time and ethylene oxide decomposition time of protective products are more than 8 days. In addition, the storage period of protective clothing made of polypropylene nonwoven fabric is short and does not meet the conditions for long-term storage. Therefore, it is of great significance to develop radiation-resistant polyethylene microfiber nonwoven materials.

[0003] Polyethylene meltblown material is an important material for breathable films in medical protective clothing and surgical gowns. Through special processes, tiny and uniform micropores and channels of 1-2μm can be formed on the polyethylene surface, so as to achieve the purpose of allowing water vapor to pass smoothly while blocking blood and other liquids. The use requirements of "three repellents and one resistance" of protective clothing are achieved, providing better protection and comfort for medical staff.

[0004] Polyethylene resin has excellent chemical stability and radiation resistance. DuPont of the United States selected it as the polymer matrix material for the preparation of limited high-end protective clothing. However, polyethylene has a low melt index, high melt viscosity, and is insoluble in solvents at room temperature and pressure. Therefore, conventional spinning methods cannot process it into microfiber non-woven materials. Compared with traditional non-woven fabric technology, the flash evaporation polyethylene non-woven fabric technology was invented by DuPont of the United States and has been used for the industrial development of high-density polyethylene non-woven fabrics. Its product "Tyvek" is used in advanced medical protection products and other fields, and has been selected as a special protective textile for Ebola virus protection in Africa. The flash evaporation technology sprays a saturated solution of high-density polyethylene under high temperature and pressure into the atmospheric environment to obtain a non-woven fabric. However, the flash evaporation method has environmental pollution problems and is not conducive to industrialization. Summary of the invention

[0005] The main purpose of the present invention is to provide a high-filtration polyethylene nonwoven material and a preparation method thereof, so as to overcome the problems in the prior art that melt-blown polypropylene fibers are not resistant to rapid sterilization by radiation, and melt-blown polyethylene microfibers have low filtration efficiency and insufficient mechanical strength.

[0006] In order to achieve the above-mentioned object, the present invention provides a high-filtration polyethylene nonwoven material, comprising a spunbond layer and a meltblown layer, wherein the meltblown layer is formed by melt-blowing a first high melt index polyethylene and a second high melt index polyethylene, the melt indexes of the first high melt index polyethylene and the second high melt index polyethylene are both greater than or equal to 200 g / 10 min, and the melt indexes of the first high melt index polyethylene and the second high melt index polyethylene are different.

[0007] The high-filtration polyethylene nonwoven material of the present invention, wherein the melt index of the first high melt index polyethylene is 200-600 g / 10 min, and the melt index of the second high melt index polyethylene is 1000-1500 g / 10 min; the mass ratio of the first high melt index polyethylene to the second high melt index polyethylene is 5-20:80-95.

[0008] The high-filtration polyethylene nonwoven material of the present invention, wherein the spunbond layer is a polyethylene spunbond layer.

[0009] The high-filtration polyethylene nonwoven material of the present invention, wherein a spinning aid is further added to the meltblown layer, and the spinning aid is at least one of dicumyl peroxide and 4,4'-thiobis(6-tert-butyl-3-methylphenol); the mass of the dicumyl peroxide is 0.01 to 0.2% of the sum of the masses of the first high melt index polyethylene and the second high melt index polyethylene, and the mass of the 4,4'-thiobis(6-tert-butyl-3-methylphenol) is 0.1 to 0.2% of the sum of the masses of the first high melt index polyethylene and the second high melt index polyethylene.

[0010] The high-filtration polyethylene nonwoven material of the present invention has a transverse and longitudinal breaking strength of ≥55N, a filtration efficiency of 95% to 97%, and a resistance of ﹤220Pa.

[0011] In order to achieve the above object, the present invention also provides a method for preparing a high-filtration polyethylene nonwoven material, wherein the high-filtration polyethylene nonwoven material comprises a spunbond layer and a meltblown layer, and the preparation method comprises:

[0012] Step 1, mixing and granulating the first high melt index polyethylene and the second high melt index polyethylene;

[0013] Step 2, melt-blowing the resin obtained in step 1 to obtain a melt-blown layer;

[0014] Step 3, compounding the spunbond layer and the meltblown layer to obtain a high-filtration polyethylene nonwoven material;

[0015] The melt indexes of the first high melt index polyethylene and the second high melt index polyethylene are both greater than or equal to 200 g / 10 min, and the melt indexes of the first high melt index polyethylene and the second high melt index polyethylene are different.

[0016] The method for preparing the high-filtration polyethylene nonwoven material of the present invention comprises the following steps: the melt index of the first high melt index polyethylene is 200-600 g / 10 min, and the melt index of the second high melt index polyethylene is 1000-1500 g / 10 min.

[0017] In the method for preparing the high-filtration polyethylene nonwoven material of the present invention, the mass ratio of the first high melt index polyethylene to the second high melt index polyethylene is 5-20:80-95.

[0018] The method for preparing a high-filtration polyethylene nonwoven material of the present invention comprises the following steps: in step 1, a spinning aid is added during the mixing and granulation of the first high melt index polyethylene and the second high melt index polyethylene, wherein the spinning aid is at least one of dicumyl peroxide and 4,4'-thiobis(6-tert-butyl-3-methylphenol); the mass of the dicumyl peroxide is 0.01-0.2% of the sum of the masses of the first high melt index polyethylene and the second high melt index polyethylene, and the mass of the 4,4'-thiobis(6-tert-butyl-3-methylphenol) is 0.1-0.2% of the sum of the masses of the first high melt index polyethylene and the second high melt index polyethylene.

[0019] The method for preparing the high-filtration polyethylene nonwoven material of the present invention, wherein step 2 is carried out in a melt-blown spinning machine, the screw temperature is 210-240° C., the hot air temperature is 230-260° C., the hot air frequency is 40-50 Hz, and the receiving distance is 20-35 cm.

[0020] Beneficial effects of the present invention:

[0021] (1) The present invention adopts high melt index polyethylene to prepare the meltblown layer through melt-blown spinning, and adopts two high melt index polyethylenes with different melt indices. The crystallization rate and fluidity of polyethylenes with different melt indices can be utilized to play the role of inducing molecular chain orientation by binding molecules in the amorphous region during the crystallization process, thereby improving the fiber reinforcement effect and effectively solving the problem of low mechanical strength of meltblown fibers.

[0022] (2) In addition, the present invention utilizes polyethylene with different melt indexes to construct a molecular chain structure with a comb-like structure to further regulate the crystallization and orientation of the fiber, thereby further enhancing the strength of the meltblown polyethylene microfibers.

[0023] (3) The polyethylenes with different melt indexes of the present invention have different fluidities. During the melt-blowing process, an inlaid composite nonwoven structure with coarser fibers as the fabric skeleton and finer fibers as the functional filter layer is formed, thereby making the melt-blown fibers have a higher filtration efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 is the nuclear magnetic carbon spectrum of the high melt index polyethylene resin of the present invention;

[0025] Figure 2 This is a scanning electron microscope photo of melt-blown microfibers obtained by melt-blowing single melt index polyethylene;

[0026] Figure 3 This is a scanning electron microscope photograph of the melt-blown polyethylene microfiber nonwoven material of Example 1 of the present invention;

[0027] Figure 4 This is a statistical table of scanning electron microscope diameters of the polyethylene microfiber nonwoven material of Example 1 of the present invention;

[0028] Figure 5 A real photo of the meltblown polyethylene microfiber nonwoven material according to Example 1 of the present invention;

[0029] Figure 6 It is a schematic diagram of the processing process of the meltblown layer of the present invention.

[0030] Wherein, the reference numerals are:

[0031] 1 Feeding device

[0032] 2 Screw Extruder

[0033] 3 Metering pump

[0034] 4. Web forming device

[0035] 5. Meltblown die head

[0036] 7. Winding device DETAILED DESCRIPTION

[0037] The technical scheme of the present invention is described in detail below. The following implementation modes are implemented on the premise of the technical scheme of the present invention, and a detailed implementation process is given. However, the protection scope of the present invention is not limited to the following implementation modes. The structures or experimental methods of specific conditions are not specified in the following implementation modes, and generally conventional conditions are followed.

[0038] The invention provides a high-filtration polyethylene nonwoven material, comprising a spunbond layer and a meltblown layer, wherein the meltblown layer is formed by meltblowing a first high melt index polyethylene and a second high melt index polyethylene, the melt indexes of the first high melt index polyethylene and the second high melt index polyethylene are both greater than or equal to 200 g / 10 min (wherein the melt index refers to the melt index tested under a load of 2.16 kg and a temperature of 190° C.), and the melt indexes of the first high melt index polyethylene and the second high melt index polyethylene are different.

[0039] The present invention adopts high melt index polyethylene to prepare the meltblown layer through melt-blown spinning, and adopts two high melt index polyethylenes with different melt indices. The crystallization rate and fluidity of polyethylenes with different melt indices can be utilized to play the role of inducing molecular chain orientation by binding molecules in the amorphous region during the crystallization process, thereby improving the fiber reinforcement effect and effectively solving the problem of low mechanical strength of meltblown fibers.

[0040] In addition, the polyethylenes with different high melt indexes of the present invention have different fluidities. During the melt-blowing process, an inlaid composite nonwoven structure is formed, in which the coarser fibers generated from the low melt index polyethylene serve as the fabric skeleton and the finer fibers generated from the high melt index polyethylene serve as the functional filter layer, thereby enabling the melt-blown fibers to have a higher filtration efficiency.

[0041] In one embodiment, the melt index of the first high melt index polyethylene is 200-600 g / 10 min, and the melt index of the second high melt index polyethylene is 1000-1500 g / 10 min (2.16 kg, 190° C.). In another embodiment, the mass ratio of the first high melt index polyethylene to the second high melt index polyethylene is 5-20:80-95.

[0042] In one embodiment, a spinning aid is further added to the meltblown layer of the present invention, which may be a processing aid, an antioxidant, etc. Specifically, the spinning aid is, for example, at least one of dicumyl peroxide and 4,4'-thiobis(6-tert-butyl-3-methylphenol); the mass of dicumyl peroxide is 0.01-0.2% of the sum of the mass of the first high melt index polyethylene and the second high melt index polyethylene, and the mass of 4,4'-thiobis(6-tert-butyl-3-methylphenol) is 0.1-0.2% of the sum of the mass of the first high melt index polyethylene and the second high melt index polyethylene.

[0043] The invention compounds two resins with different high melt indexes, and then prepares a polyethylene microfiber nonwoven material with a self-reinforced structure and high filtration efficiency through a very small amount of cross-linking effect of a small amount of auxiliary agent diisopropylbenzene peroxide, thereby solving the problems that the existing melt-blown polypropylene fiber is not resistant to rapid sterilization by radiation, and the melt-blown polyethylene microfiber has low filtration efficiency and insufficient mechanical strength.

[0044] In one embodiment, the spinning aid of the present invention is added during the mixed granulation process of the first high melt index polyethylene and the second high melt index polyethylene. The spinning aid of the present invention, such as dicumyl peroxide, preferentially reacts with the polyethylene with a higher melt index to induce free radicals, forming a polyethylene comb chain structure with a relatively low melt index polyethylene as the skeleton and a relatively high melt index polyethylene as the comb chain. The existence of this structure can efficiently induce the nucleation effect of the polyethylene melt-blowing process, thereby inducing chain orientation under hot air micro-drafting to obtain self-reinforced polyethylene microfibers.

[0045] The spunbond layer of the present invention is prepared by a spunbond method. The present invention does not particularly limit the preparation process of the spunbond layer, and conventional preparation methods in the art may be used. In one embodiment, the spunbond layer of the present invention is a polyethylene spunbond layer.

[0046] The high-filtration polyethylene nonwoven material of the present invention has a transverse and longitudinal breaking strength of ≥55N, a filtration efficiency of 95% to 97%, and a resistance of <220 Pa. Medical protective clothing and surgical clothing can be prepared from the polyethylene nonwoven material of the present invention.

[0047] The present invention also provides a method for preparing the high-filtration polyethylene nonwoven material. The high-filtration polyethylene nonwoven material comprises a spunbond layer and a meltblown layer. The preparation method comprises:

[0048] Step 1, mixing and granulating the first high melt index polyethylene and the second high melt index polyethylene;

[0049] Step 2, melt-blowing the resin obtained in step 1 to obtain a melt-blown layer;

[0050] Step 3, compounding the spunbond layer and the meltblown layer to obtain a high-filtration polyethylene nonwoven material;

[0051] The melt indexes of the first high melt index polyethylene and the second high melt index polyethylene are both greater than or equal to 200 g / 10 min, and the melt indexes of the first high melt index polyethylene and the second high melt index polyethylene are different.

[0052] In one embodiment, the melt index of the first high melt index polyethylene is 200-600 g / 10 min, and the melt index of the second high melt index polyethylene is 1000-1500 g / 10 min; the mass ratio of the first high melt index polyethylene to the second high melt index polyethylene is 5-20:80-95.

[0053] The present invention does not particularly limit the mixing and granulation process of the first high melt index polyethylene and the second high melt index polyethylene. In one embodiment, the mixing and granulation of the first high melt index polyethylene and the second high melt index polyethylene are carried out in a twin-screw extruder, and the temperature of the screw feed section to the homogenizing section is set at 120 to 160°C, and the screw speed is, for example, 50-100rpm.

[0054] In one embodiment, in step 1, a spinning aid is added during the mixing and granulation of the first high melt index polyethylene and the second high melt index polyethylene, which may be a processing aid, an antioxidant, etc. Specifically, the spinning aid is at least one of dicumyl peroxide and 4,4'-thiobis(6-tert-butyl-3-methylphenol); the mass of dicumyl peroxide is 0.01-0.2% of the sum of the mass of the first high melt index polyethylene and the second high melt index polyethylene, and the mass of 4,4'-thiobis(6-tert-butyl-3-methylphenol) is 0.1-0.2% of the sum of the mass of the first high melt index polyethylene and the second high melt index polyethylene.

[0055] The spunbond layer of the present invention is prepared by a spunbond method. The present invention does not particularly limit the preparation process of the spunbond layer, and conventional preparation methods in the art may be used. In one embodiment, the spunbond layer of the present invention is a polyethylene spunbond layer.

[0056] In one embodiment, after the first high melt index polyethylene and the second high melt index polyethylene are mixed and granulated, they enter a meltblown spinning machine, the screw temperature is 210-240°C, the hot air temperature is 230-260°C, the hot air frequency is 40-50Hz, the receiving distance is 20-35cm, and the polyethylene microfibers obtained by meltblowing settle on the web forming device to form a meltblown layer.

[0057] The meltblown layer processing of the present invention is for example as follows Figure 6 The first high melt index polyethylene and the second high melt index polyethylene enter the screw extruder 2 through the feeding device 1, and the composite resin is extruded and granulated, and then passes through the metering pump 3 and the melt-blowing die head 5, and settles on the web forming device 4, and the obtained melt-blown layer is wound up by the winding device 7.

[0058] Then, the spunbond layer is compounded with the meltblown layer to obtain a polyethylene nonwoven material. The present invention does not particularly limit the process of compounding the spunbond layer with the meltblown layer, and conventional processes in the art can be used, such as hot roll pressing.

[0059] The high-filtration polyethylene nonwoven material of the present invention not only has high mechanical properties and relatively high filtration performance, but also has good barrier properties and radiation resistance. When electron beam radiation sterilization or X-ray sterilization is selected, the metering control is 16 to 27 kgy, and there is no Escherichia coli colony, bacterial colony, fungal colony, etc. after irradiation.

[0060] The technical solution of the present invention will be further described in detail below through specific embodiments.

[0061] Source of raw materials or equipment:

[0062] (1) Raw materials:

[0063] High melt index polyethylene, provided by Daqing Chemical Research Center of PetroChina Co., Ltd. Figure 1 is the nuclear magnetic carbon spectrum of the high melt index polyethylene resin of the present invention;

[0064] Dicumyl peroxide, produced by Sigma-Aldrich (Shanghai) Trading Co., Ltd.;

[0065] The antioxidant 4,4'-thiobis(6-tert-butyl-3-methylphenol) was produced by Wuhan Smack Biotechnology Co., Ltd.

[0066] (2) Equipment:

[0067] Twin-screw compounding equipment, designed and manufactured by Donghua University;

[0068] Meltblown spinning machine, produced by Tuoren Group.

[0069] Example 1

[0070] 1) Twin-screw preparation of composite resin:

[0071] 20kg of polyethylene powder with a melt index of 200g / 10min, 80kg of polyethylene powder with a melt index of 1000g / 10min, 0.1kg of diisopropylbenzene peroxide, and 0.1kg of 4,4'-thiobis(6-tert-butyl-3-methylphenol) were fully mechanically premixed, and then added into a twin screw for reactive extrusion to obtain a composite resin. The screw feed section to the homogenizing section were set at a temperature of 110-140°C, and the screw speed was 50rpm.

[0072] 2) Meltblown polyethylene microfiber nonwoven material:

[0073] The above composite resin was melt-blown by Tuoren Group melt-blown spinning machine to prepare polyethylene microfibers. The temperature of the screw compression section and the homogenization section was set at 120-240°C, the temperature of the melt-blown component was 240°C, the hot air temperature was set at 260°C, the hot air frequency was set at 45Hz, and the receiving distance was 35cm to obtain a melt-blown polyethylene microfiber nonwoven material. The scanning electron microscope photo is shown in Figure 3 The diameter statistics of scanning electron microscope are shown in Figure 4 As shown, the actual photo of meltblown polyethylene microfiber nonwoven material is as follows Figure 5 As shown. Figure 3 and 4 As shown, the diameter of the meltblown microfiber nonwoven material is mainly 1-2um, and it also contains a small amount of coarse fibers of 5-9um. The transverse and longitudinal breaking strengths of the microfiber nonwoven material reach 5±0.13N and 4.5±0.17N.

[0074] Figure 2The scanning electron microscope photograph of melt-blown microfibers obtained by melt-blowing single melt index polyethylene shows that the diameter of the fibers formed by single melt index polyethylene is relatively uniform. The microfibers prepared by the present invention can form a nonwoven material with a coarse and fine interlaced spatial network structure.

[0075] 3) Polyethylene nonwoven materials:

[0076] The melt-blown microfibers are compounded with spunbonded polyethylene nonwoven fabrics to obtain polyethylene nonwoven materials. Mask products are prepared from them, and the spunbonded layer / melt-blown layer weight ratio is controlled at 30-50:5-10, and the filtration efficiency reaches 96%, and the resistance is ﹤220Pa. Protective clothing is prepared based on spunbonded polyethylene nonwoven fabrics and the melt-blown microfibers, and the spunbonded layer / melt-blown layer weight ratio is controlled at 30-50:3-5, and the transverse and longitudinal breaking strength of the protective clothing is greater than 65N.

[0077] Example 2

[0078] 1) Twin-screw preparation of composite resin:

[0079] 5kg of polyethylene powder with a melt index of 400g / 10min, 95kg of polyethylene powder with a melt index of 1200g / 10min, 0.01kg of diisopropylbenzene peroxide, and 0.2kg of 4,4'-thiobis(6-tert-butyl-3-methylphenol) were fully mechanically premixed, and then added into a twin screw for reactive extrusion to obtain a composite resin. The screw feed section to the homogenizing section were set at a temperature of 110-140°C, and the screw speed was 100rpm.

[0080] 2) Meltblown polyethylene microfiber nonwoven material:

[0081] The above composite resin was melt-blown by Tuoren Group's melt-blown spinning machine to prepare polyethylene microfibers. The temperature of the screw compression section and the homogenization section was set at 120-240°C, the temperature of the melt-blown assembly was 240°C, the hot air temperature was set at 230°C, the hot air frequency was set at 50Hz, and the receiving distance was 20cm to obtain a melt-blown polyethylene microfiber nonwoven material. The diameter of the melt-blown microfiber nonwoven material is mainly 1-3um, and it also contains a small amount of 4-10um coarse fibers. The transverse and longitudinal breaking strengths of the microfiber nonwoven material reached 5.7±0.15N and 5.4±0.13N.

[0082] 3) Polyethylene nonwoven materials:

[0083] The melt-blown microfibers are compounded with spunbonded polyethylene nonwoven fabrics to obtain polyethylene nonwoven materials. Mask products are prepared from them, and the gram weight ratio of the spunbonded layer / melt-blown layer is controlled at 30-50:5-10, and the filtration efficiency reaches 97%, and the resistance is ﹤200Pa. Protective clothing is prepared based on spunbonded polyethylene nonwoven fabrics and the melt-blown microfibers, and the gram weight ratio of the spunbonded layer / melt-blown layer is controlled at 30-50:3-5, and the transverse and longitudinal breaking strength of the protective clothing is greater than 62N.

[0084] Example 3

[0085] 1) Twin-screw preparation of composite resin:

[0086] 15kg of polyethylene powder with a melt index of 600g / 10min, 85kg of polyethylene powder with a melt index of 1500g / 10min, 0.05kg of diisopropylbenzene peroxide, and 0.1kg of 4,4'-thiobis(6-tert-butyl-3-methylphenol) were fully mechanically premixed, and then added into a twin screw for reactive extrusion to obtain a composite resin. The screw feed section to the homogenizing section were set at a temperature of 110-140°C, and the screw speed was 75rpm.

[0087] 2) Meltblown polyethylene microfiber nonwoven material:

[0088] The above composite resin was melt-blown by Tuoren Group's melt-blown spinning machine to prepare polyethylene microfibers. The temperature of the screw compression section and the homogenization section was set at 120-240°C, the temperature of the melt-blown assembly was 230°C, the hot air temperature was set at 210°C, the hot air frequency was set at 40Hz, and the receiving distance was 35cm to obtain a melt-blown polyethylene microfiber nonwoven material. The diameter of the melt-blown microfiber nonwoven material is mainly 1-2um, and it also contains a small amount of 5-9um coarse fibers. The transverse and longitudinal breaking strengths of the microfiber nonwoven material reached 5±0.13N and 4.5±0.17N.

[0089] 3) Polyethylene nonwoven materials:

[0090] The melt-blown microfibers are compounded with spunbonded polyethylene nonwoven fabrics to obtain polyethylene nonwoven materials. Mask products are prepared from them, and the gram weight ratio of the spunbonded layer / melt-blown layer is controlled at 30-50:5-10, and the filtration efficiency reaches 96%, and the resistance is ﹤220Pa. Protective clothing is prepared based on spunbonded polyethylene nonwoven fabrics and the melt-blown microfibers, and the gram weight ratio of the spunbonded layer / melt-blown layer is controlled at 30-50:3-5, and the transverse and longitudinal breaking strength of the protective clothing is greater than 65N.

[0091] Example 4

[0092] 1) Twin-screw preparation of composite resin:

[0093] 20kg of polyethylene powder with a melt index of 200g / 10min, 80kg of polyethylene powder with a melt index of 1200g / 10min, 0.01kg of diisopropylbenzene peroxide, and 0.2kg of 4,4'-thiobis(6-tert-butyl-3-methylphenol) were fully mechanically premixed, and then added into a twin screw for reactive extrusion to obtain a composite resin. The screw feed section to the homogenizing section were set at a temperature of 110-140°C, and the screw speed was 85rpm.

[0094] 2) Meltblown polyethylene microfiber nonwoven material:

[0095] The above composite resin was melt-blown by Tuoren Group's melt-blown spinning machine to prepare polyethylene microfibers. The temperatures of the screw compression section and the homogenization section were set at 120-210°C, the melt-blown assembly temperature was 210°C, the hot air temperature was set at 250°C, the hot air frequency was set at 45Hz, and the receiving distance was 30cm to obtain a melt-blown polyethylene microfiber nonwoven material. The diameter of the melt-blown microfiber nonwoven material is mainly 1-3um, and it also contains a small amount of 4-9um coarse fibers. The transverse and longitudinal breaking strengths of the microfiber nonwoven material reached 5.7±0.22N and 5.5±0.15N.

[0096] 3) Polyethylene nonwoven materials:

[0097] The melt-blown microfibers are compounded with spunbonded polyethylene nonwoven fabrics to obtain polyethylene nonwoven materials. Mask products are prepared from them, and the gram weight ratio of the spunbonded layer / melt-blown layer is controlled at 30-50:5-10, and the filtration efficiency reaches 95%, and the resistance is ﹤220Pa. Protective clothing is prepared based on spunbonded polyethylene nonwoven fabrics and the melt-blown microfibers, and the gram weight ratio of the spunbonded layer / melt-blown layer is controlled at 30-50:3-5, and the transverse and longitudinal breaking strength of the protective clothing is greater than 66N.

[0098] Comparative Example 1

[0099] 1) Twin screw resin preparation:

[0100] 100 kg of polyethylene powder with a melt index of 200 g / 10 min was added to a twin screw for extrusion to obtain a resin treated once, wherein the temperature of the screw feed section to the homogenization section was set at 110 to 140° C., and the screw speed was 50 rpm.

[0101] 2) Meltblown polyethylene microfiber nonwoven material:

[0102] The above-mentioned treated resin was melt-blown by a melt-blown spinning machine of Tuoren Group to prepare polyethylene microfibers. The temperature of the screw compression section and the homogenization section was set at 120-240°C, the temperature of the melt-blown assembly was 240°C, the hot air temperature was set at 260°C, the hot air frequency was set at 45Hz, and the receiving distance was 35cm to obtain a melt-blown polyethylene microfiber nonwoven material. The diameter of the melt-blown microfiber nonwoven material was mainly 1-1.8um. ​​The transverse and longitudinal breaking strengths of the microfiber nonwoven material reached 4.4±0.15N and 4.2±0.16N.

[0103] 3) Polyethylene nonwoven materials:

[0104] The melt-blown microfibers were compounded with spunbonded polyethylene nonwoven fabrics to obtain polyethylene nonwoven materials. Mask products were prepared from them, and the spunbonded layer / melt-blown layer weight ratio was controlled at 30-50:5-10, and the filtration efficiency reached 94%, and the resistance was ﹤210Pa. Protective clothing was prepared based on spunbonded polyethylene nonwoven fabrics and the melt-blown microfibers, and the spunbonded layer / melt-blown layer weight ratio was controlled at 30-50:3-5, and the transverse and longitudinal breaking strength of the protective clothing was 62N.

[0105] Of course, the present invention may have many other embodiments. Without departing from the spirit and essence of the present invention, technicians familiar with the field may make various corresponding changes and deformations based on the present invention, but these corresponding changes and deformations should all fall within the scope of protection of the claims of the present invention.

Claims

1. A high filtration polyethylene nonwoven material, characterized in that, The invention comprises a spunbond layer and a meltblown layer, wherein the meltblown layer is formed by meltblowing a first high melt index polyethylene and a second high melt index polyethylene, the melt indexes of the first high melt index polyethylene and the second high melt index polyethylene are both greater than or equal to 200 g / 10 min, and the melt indexes of the first high melt index polyethylene and the second high melt index polyethylene are different.

2. The high filtration polyethylene nonwoven material according to claim 1, characterized in that: The melt index of the first high melt index polyethylene is 200-600 g / 10 min, and the melt index of the second high melt index polyethylene is 1000-1500 g / 10 min; the mass ratio of the first high melt index polyethylene to the second high melt index polyethylene is 5-20:80-95.

3. The high filtration polyethylene nonwoven material according to claim 1, characterized in that: The spunbond layer is a polyethylene spunbond layer.

4. The high filtration polyethylene nonwoven material according to claim 1, characterized in that: A spinning aid is also added to the meltblown layer, and the spinning aid is at least one of dicumyl peroxide and 4,4'-thiobis(6-tert-butyl-3-methylphenol); the mass of the dicumyl peroxide is 0.01 to 0.2% of the sum of the masses of the first high melt index polyethylene and the second high melt index polyethylene, and the mass of the 4,4'-thiobis(6-tert-butyl-3-methylphenol) is 0.1 to 0.2% of the sum of the masses of the first high melt index polyethylene and the second high melt index polyethylene.

5. The high filtration polyethylene nonwoven material according to claim 1, characterized in that: The high-filtration polyethylene nonwoven material has a transverse and longitudinal breaking strength of ≥55N, a filtration efficiency of 95% to 97%, and a resistance of ≤220Pa.

6. A method for preparing a high-filtration polyethylene nonwoven material, characterized in that: The high-filtration polyethylene nonwoven material comprises a spunbond layer and a meltblown layer, and the preparation method comprises: Step 1, mixing and granulating the first high melt index polyethylene and the second high melt index polyethylene; Step 2, melt-blowing the resin obtained in step 1 to obtain a melt-blown layer; Step 3, compounding the spunbond layer and the meltblown layer to obtain a high-filtration polyethylene nonwoven material; The melt indexes of the first high melt index polyethylene and the second high melt index polyethylene are both greater than or equal to 200 g / 10 min, and the melt indexes of the first high melt index polyethylene and the second high melt index polyethylene are different.

7. The method for preparing a high filtration polyethylene nonwoven material according to claim 6, characterized in that: The melt index of the first high melt index polyethylene is 200-600 g / 10 min, and the melt index of the second high melt index polyethylene is 1000-1500 g / 10 min.

8. The method for preparing a high filtration polyethylene nonwoven material according to claim 6, characterized in that: The mass ratio of the first high melt index polyethylene to the second high melt index polyethylene is 5-20:80-95.

9. The method for preparing a high filtration polyethylene nonwoven material according to claim 6, characterized in that: In step 1, a spinning aid is added during the mixing and granulation of the first high melt index polyethylene and the second high melt index polyethylene, and the spinning aid is at least one of dicumyl peroxide and 4,4'-thiobis(6-tert-butyl-3-methylphenol); the mass of the dicumyl peroxide is 0.01 to 0.2% of the sum of the masses of the first high melt index polyethylene and the second high melt index polyethylene, and the mass of the 4,4'-thiobis(6-tert-butyl-3-methylphenol) is 0.1 to 0.2% of the sum of the masses of the first high melt index polyethylene and the second high melt index polyethylene.

10. The method for preparing a high filtration polyethylene nonwoven material according to claim 6, characterized in that: Step 2 is carried out in a melt-blown spinning machine, with a screw temperature of 210-240° C., a hot air temperature of 230-260° C., a hot air frequency of 40-50 Hz, and a receiving distance of 20-35 cm.

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