Polyethylene non-woven fabric as well as preparation method, preparation device and application thereof

Abstract

The invention belongs to the technical field of preparation of non-woven fabrics, and discloses a polyethylene non-woven fabric as well as a preparation method, a preparation device and application thereof. The polyethylene non-woven fabric is prepared from the following raw materials in percentage by weight: based on the total weight of the raw materials, the content of polyethylene is 20-50%; 1%-10% of ultra-high molecular weight polyethylene; 45%-75% of white oil; 1%-2% of an antioxidant; 1%-3% of a conductive agent; the weight-average molecular weight of the polyethylene is 50,000-200,000; the viscosity average molecular weight of the ultra-high molecular weight polyethylene is 0.5 million to 5 million. The polyethylene non-woven fabric disclosed by the invention has excellent mechanical properties, good air permeability and microorganism barrier property, low production cost and suitability for industrial production.

Description

Technical Field

[0001] This invention belongs to the field of nonwoven fabric preparation technology, specifically relating to a polyethylene nonwoven fabric, a method for preparing the polyethylene nonwoven fabric, an apparatus for preparing the polyethylene nonwoven fabric, and the application of the polyethylene nonwoven fabric. Background Technology

[0002] High-strength breathable membranes are widely used in waterproofing, protection, transportation, and medical fields due to their excellent properties such as waterproofing, breathability, lightweight, strength, toughness, tear resistance, and puncture resistance. They are a core material for medical device packaging and high-end medical and health protection.

[0003] Polyethylene (PE) is widely used in various fields such as packaging materials, pipes, containers, films, and electronics due to its excellent chemical stability, good mechanical properties, easy processing, and low cost. It is one of the most in-demand materials in the current polymer processing market. However, PE has poor spinnability, high melt viscosity, and is difficult to spin into fibers, requiring modification to improve its spinnability.

[0004] Electrospinning is currently the most commonly used technique for preparing micro and nanofibers. Depending on the raw materials, it can be divided into solution electrospinning and melt electrospinning. Compared to solution electrospinning, melt electrospinning has advantages such as not requiring toxic solvents, high raw material utilization, and being environmentally friendly and pollution-free. It is also suitable for widely used polymers such as PP and PLA. However, due to the high viscosity of polymer melts, traditional single-needle melt electrospinning suffers from nozzle clogging and low fiber preparation efficiency. To address this issue, Yang et al. developed a melt differential electrospinning device (US20160068999A1 Melt Differential Electrospinning Device and Process) using an open conical nozzle, solving the problem of low fiber preparation efficiency in melt electrospinning. Summary of the Invention

[0005] To meet the demand of related industries for high-performance polyethylene nonwoven materials and overcome the shortcomings of existing technologies, the purpose of this invention is to provide a polyethylene nonwoven fabric, its preparation method, preparation device, and application. The polyethylene nonwoven fabric of this invention has good mechanical properties, air permeability, and microbial barrier properties, and has low production cost, making it suitable for industrial production.

[0006] A first aspect of the present invention provides a polyethylene nonwoven fabric made from the following raw materials by weight percentage: based on the total weight of the raw materials, the polyethylene content is 20%-50%; ultra-high molecular weight polyethylene is 1%-10%; white oil is 45%-75%; antioxidant is 1%-2%; and conductive agent is 1%-3%.

[0007] The weight-average molecular weight of the polyethylene is 50,000 to 200,000; the viscosity-average molecular weight of the ultra-high molecular weight polyethylene is 500,000 to 5,000,000.

[0008] A second aspect of the present invention provides a method for preparing the above-mentioned polyethylene nonwoven fabric, the method comprising the following steps:

[0009] 1) Mix and melt the raw materials, cool and condense to obtain a gel, and break the gel into spinning particles;

[0010] 2) After the spinning particles are melted and extruded, they are ejected through the die head of the spinning system. Under the coordinated stretching of the wind field and the electrostatic field, the resulting polyethylene fibers are deposited on the receiving mesh belt to form polyethylene nonwoven fabric.

[0011] A third aspect of the present invention provides an apparatus for preparing polyethylene nonwoven fabric using the above-described preparation method. The apparatus includes: a continuous screw extrusion spinning system, a hot air generating system, a suction system, a high-voltage electrostatic generating system, and a receiving mesh belt.

[0012] According to the material flow, the receiving mesh belt is located downstream of the continuous screw extrusion spinning system, the suction system is located inside the receiving mesh belt, the hot air generation system and the suction system form an air field, and the high-voltage electrostatic generation system provides an electrostatic field. The air field and the electrostatic field work together to act on the polyethylene fibers ejected from the die of the continuous screw extrusion spinning system.

[0013] The fourth aspect of the present invention provides the application of the above-described polyethylene nonwoven fabric in the fields of medical breathable membrane packaging, protective clothing, construction, radiation cooling and filtration.

[0014] Compared with the prior art, the technical solution of the present invention has the following advantages:

[0015] (1) The nonwoven fabric produced by this invention has a uniform and dense internal fiber structure, good mechanical properties, and a tensile strength of up to 6.5kN / m, while the tensile strength of conventional polyethylene nonwoven fabric is difficult to reach more than 3.0kN / m. In addition, the nonwoven fabric has excellent microbial shielding performance and waterproof and breathable properties.

[0016] (2) This invention can realize the low-cost production of medium and high strength polyethylene fiber nonwoven fabric. The nonwoven fabric preparation process is formed in one step. The preparation device has a reasonable structure, simple operation, and is suitable for industrial production.

[0017] Other features and advantages of the present invention will be described in detail in the following detailed description section. Attached Figure Description

[0018] Figure 1 A schematic diagram of a polyethylene nonwoven fabric preparation device;

[0019] Figure 2 A porous die head for a polyethylene nonwoven fabric preparation device;

[0020] Figure 3 The differential die head of the polyethylene nonwoven fabric preparation device;

[0021] Figure 4 The image shows an electron microscope image of the polyethylene nonwoven fabric from Example 1.

[0022] Explanation of reference numerals in the attached drawings: 1-Motor; 2-Diverter plate; 3-Die head; 4-Cyclone airflow auxiliary device; 5-Perforated acrylic plate; 6-Feed hopper; 7-Twin screw; 8-Adapter; 9-Barrel; 10-Perforated copper plate; 11-Fiber collection net. Detailed Implementation

[0023] The following provides a detailed description of specific embodiments of the present invention. It should be understood that the specific embodiments described herein are for illustrative and explanatory purposes only and are not intended to limit the scope of the invention.

[0024] According to a first aspect of the present invention, a polyethylene nonwoven fabric is provided, which is made from the following raw materials by weight percentage: based on the total weight of the raw materials, the content of polyethylene is 20%-50%; ultra-high molecular weight polyethylene is 1%-10%; white oil is 45%-75%; antioxidant is 1%-2%; and conductive agent is 1%-3%.

[0025] The weight-average molecular weight of the polyethylene is 50,000 to 200,000; the viscosity-average molecular weight of the ultra-high molecular weight polyethylene is 500,000 to 5,000,000.

[0026] In this invention, the melt flow index of the ultra-high molecular weight polyethylene at 190°C and 2.16 kg load is less than 5 g / 10 min, preferably less than 2 g / 10 min.

[0027] According to the present invention, the conductive agent may be a polyphenolic acid, preferably selected from at least one of 2,5-dihydroxybenzoic acid, gallic acid, caffeic acid, ferulic acid, vanillic acid, p-hydroxycinnamic acid, rosmarinic acid and sarsaparilla acid.

[0028] Preferably, the polyethylene nonwoven fabric has a fiber diameter of 1-10 μm, more preferably 3-9 μm, and a thickness of 0.1-0.2 mm.

[0029] The polyethylene nonwoven fabric of the present invention has an air permeability greater than 1 μm / Pa·s, preferably 5-40 μm / Pa·s, and a water vapor permeability greater than 1000 g / m³. 2 • 24h, preferably 1100-4000g / m 2• After 24 hours, the microbial barrier performance (LRV) is greater than 3, preferably 3-6, and the tensile strength is greater than 5kN / m, reaching 6.5kN / m.

[0030] According to a second aspect of the present invention, the present invention provides a method for preparing the above-described polyethylene nonwoven fabric, the method comprising the following steps:

[0031] 1) Mix and melt the raw materials, cool and condense to obtain a gel, and break the gel into spinning particles;

[0032] 2) After the spinning particles are melted and extruded, they are ejected through the die head of the spinning system. Under the coordinated stretching of the wind field and the electrostatic field, the resulting polyethylene fibers are deposited on the receiving mesh belt to form polyethylene nonwoven fabric.

[0033] In step 1) of this invention, the melting conditions include stirring at 170-240°C for 1-2 hours.

[0034] According to the present invention, in step 2), the temperature of melt extrusion is 160-180°C and the temperature of the die head is 180-240°C.

[0035] In this invention, the hot air temperature of the wind field is 200-290℃, preferably 210-290℃, the wind field intensity is 0.1-0.6MPa, preferably 0.1-0.5MPa, and the electrostatic field intensity is 5-50KV, preferably 20-50KV.

[0036] According to the present invention, the spinning particles are melted, plasticized, and sheared using a screw extruder, causing the polyethylene melt to be extruded and spun through a die. A synergistic airflow and electrostatic field are applied at the die, and the polymer is stretched into fibers using the stretching effect of the airflow and electrostatic field. The fibers adhere to a receiving mesh belt, resulting in a polyethylene nonwoven fabric with good air permeability.

[0037] According to a specific embodiment of the present invention, the preparation method of polyethylene nonwoven fabric includes: 1. Drying polyethylene granules in a constant temperature forced-air drying oven at 60°C for 6-12 hours; preparing raw materials according to the mass ratio; stirring the raw materials at 170-240°C for 1-2 hours; condensing to prepare polyethylene gel; and then crushing the condensed gel into spinning particles using a crusher. 2. Setting the twin-screw temperature to 160-180°C, the barrel temperature to 170-180°C, the distributor plate temperature to 170-180°C, and the die head temperature to 180-240°C; turning on the hot air system and the high-voltage electrostatic generation system; controlling the pressure at the hot air inlet to 0.1-0.6MPa; and controlling the voltage at the hollow electrode plate to 5KV-50KV. The spinning particles are fed through the hopper and fully preheated, sheared and blended by the screw. They are then melted through the barrel and the distributor plate, and sprayed out through the die head. Under the coordinated stretching of the wind field and the electric field, the polyethylene fibers are finally deposited on the receiving mesh belt to form polyethylene nonwoven fabric.

[0038] According to a third aspect of the present invention, the present invention provides an apparatus for preparing polyethylene nonwoven fabric using the above-described preparation method, the apparatus comprising: a continuous screw extrusion spinning system, a hot air generating system, a suction system, a high-voltage electrostatic generating system, and a receiving mesh belt;

[0039] According to the material flow, the receiving mesh belt is located downstream of the continuous screw extrusion spinning system, the suction system is located inside the receiving mesh belt, the hot air generation system and the suction system form an air field, and the high-voltage electrostatic generation system provides an electrostatic field. The air field and the electrostatic field work together to act on the polyethylene fibers ejected from the die of the continuous screw extrusion spinning system.

[0040] The continuous screw extrusion spinning system, hot air generation system, suction system, and high-voltage electrostatic generation system in this invention can all adopt conventional configurations in the prior art, as long as they can achieve the corresponding functions.

[0041] The screw of the continuous screw extrusion spinning system of the present invention includes, but is not limited to, a corrugated screw capable of generating pressure, with an internal extruder pressure of 8MPa-20MPa.

[0042] The suction system inside the receiving mesh belt of this invention facilitates the deposition of drawn fibers on the receiving mesh belt.

[0043] The die head in this invention can be a multi-hole die head (such as...) Figure 2 (as shown) or differential module (such as Figure 3 (As shown). The orifice diameter (spinneret diameter) of the multi-hole die head is preferably 0.2mm-0.3mm.

[0044] The hot air generation system, the suction system, and the high-voltage electrostatic generation system of this invention constitute a wind farm coordinated system. The hot air temperature range is 200-290℃, the wind field intensity is 0.1-0.6MPa, and the electrostatic field intensity is 5KV-50KV.

[0045] According to the present invention, the hot air outlet of the hot air generating system is located on the upper and lower sides of the mold head, and hot air is blown out from the upper and lower sides of the mold head. The electrostatic field is applied between the mold head and the receiving mesh belt.

[0046] According to a fourth aspect of the present invention, the present invention provides the application of the above-described polyethylene nonwoven fabric in the fields of medical breathable membrane packaging, protective clothing, construction, radiation refrigeration and filtration.

[0047] The substances and parameters not limited in this invention can be selected according to existing technology, which is a conventional technical means in this field.

[0048] The present invention will be further described below with reference to embodiments. However, the invention is not limited to these embodiments.

[0049] In the following examples and comparative examples, the sources of raw materials and the methods for obtaining data include:

[0050] Polyethylene: Zhenhai Refining & Chemical R546u, Sinopec Shanghai Petrochemical Co., Ltd.;

[0051] Ultra-high molecular weight polyethylene: L0504F, China Petroleum & Chemical Corporation;

[0052] White oil: Lanhua Lubrication Technology Co., Ltd.;

[0053] Antioxidant 1010: Shanghai Aladdin Biochemical Technology Co., Ltd.;

[0054] Gallic acid: Shanghai Aladdin Biochemical Technology Co., Ltd.

[0055] Fiber diameter: Detected according to GB / T36422-2018 "Determination of Microstructure and Diameter of Chemical Fibers by Scanning Electron Microscopy";

[0056] Air permeability: Tested according to ISO 5636.5:2013, using the Bentssen method;

[0057] Water vapor transmission rate: Tested according to GB / T 17146-2015;

[0058] Microbial shielding performance: tested according to YY / T 0681.10-2011;

[0059] Tensile strength: Tested according to YY / T 0698.9-2009.

[0060] Example 1

[0061] use Figure 1 The apparatus shown is for preparing polyethylene nonwoven fabric. Specifically, the apparatus consists of a motor 1, a flow divider 2, a die head 3, a cyclone airflow auxiliary device 4, a perforated acrylic plate 5, a feed hopper 6, a twin-screw extruder 7, an adapter 8, a barrel 9, a perforated copper plate 10, and a fiber collection net 11. After drying, the polyethylene material is added to the feed hopper 6 and driven by the motor 1 into the twin-screw extruder 7. After being heated and melted by the adapter 8 and the barrel 9, it passes through the flow divider 2 and enters the die head 3 (e.g., ...). Figure 3 (As shown) and ejected through the die head, it is deposited onto the fiber collection net 11 behind the perforated copper plate 10 under the synergistic effect of the airflow field of the cyclone airflow auxiliary device 4 and the electric field of the perforated copper plate 10.

[0062] The preparation method of polyethylene nonwoven fabric includes: 1. Drying polyethylene granules in a drying oven at 60℃ for 8 hours. Mixing the raw materials according to the following mass percentages: linear low-density polyethylene R546u 45%, ultra-high molecular weight polyethylene 3%, white oil 50%, antioxidant 1%, and conductive agent (gallic acid) 1%. Stirring at 220℃ for 2 hours, and condensing to prepare polyethylene gel. The condensed gel is then crushed into spinning gel particles. 2. Setting the twin-screw temperature to 160℃, the barrel temperature to 170℃, the distributor plate temperature to 160℃, and the nozzle temperature to 220℃. Turning on the hot air system and the high-voltage electrostatic generation system, the hot air temperature is 270℃, the pressure at the hot air inlet is controlled at 0.4MPa, and the voltage at the hollow electrode plate is controlled at 40KV. The spinning gel particles are added to the feed hopper and fully preheated and sheared by the screw. They are then melted through the barrel and the distributor plate, and sprayed out through the nozzle. Under the coordinated stretching of the wind field and the electric field, the polyethylene fibers are finally deposited on the receiving mesh belt to form polyethylene nonwoven fabric.

[0063] Example 2

[0064] The difference from Example 1 is that the raw materials, by weight percentage, are: 40% linear low-density polyethylene R546u, 3% ultra-high molecular weight polyethylene, 55% white oil, 1% antioxidant, and 1% conductive agent (gallic acid). All other components are the same.

[0065] Example 3

[0066] The difference from Example 1 is that the raw materials, by weight percentage, are: 40% linear low-density polyethylene R546u, 5% ultra-high molecular weight polyethylene, 53% white oil, 1% antioxidant, and 1% conductive agent (gallic acid). All other components are the same.

[0067] Example 4

[0068] The difference from Example 1 is that the raw materials, by weight percentage, are: 35% linear low-density polyethylene R546u, 5% ultra-high molecular weight polyethylene, 58% white oil, 1% antioxidant, and 1% conductive agent (gallic acid). All other components are the same.

[0069] Example 5

[0070] The difference from Example 1 is that the raw materials, by weight percentage, are: 30% linear low-density polyethylene R546u, 5% ultra-high molecular weight polyethylene, 63% white oil, 1% antioxidant, and 1% conductive agent (gallic acid). All other components are the same.

[0071] Example 6

[0072] The difference from Example 1 is that the raw materials, by weight percentage, are: 25% linear low-density polyethylene R546u, 5% ultra-high molecular weight polyethylene, 68% white oil, 1% antioxidant, and 1% conductive agent (gallic acid). All other components are the same.

[0073] Comparative Example 1

[0074] The difference from Example 1 is that the raw materials, by weight percentage, consist of 48% linear low-density polyethylene R546u, 50% white oil, 1% antioxidant, and 1% conductive agent (gallic acid), and ultra-high molecular weight polyethylene is not used. All other aspects are the same.

[0075] The nonwoven fabrics prepared in each embodiment and comparative example were subjected to performance tests, and the results are shown in Table 1.

[0076] Table 1

[0077]

[0078]

[0079] Compared with Comparative Example 1, the addition of ultra-high molecular weight polyethylene (UHMWPE) in Examples 1-6 greatly improves the mechanical properties of the membrane material. However, the addition of UHMWPE increases the viscosity of the material system, makes fiber spinning more difficult, and increases the average fiber diameter. Air permeability, water vapor transmission, and microbial barrier performance are contradictory. Under the premise of ensuring that the mechanical properties meet the requirements, the polyethylene component plays a major role in bonding and microbial barrier performance. This invention effectively balances the relationship between mechanical properties, air permeability, and microbial barrier performance, resulting in a nonwoven fabric with superior overall performance.

[0080] The various embodiments of the present invention have been described above. These descriptions are exemplary and not exhaustive, nor are they limited to the disclosed embodiments. Many modifications and variations will be apparent to those skilled in the art without departing from the scope and spirit of the described embodiments.

Claims

1. A polyethylene nonwoven fabric, characterized in that, The polyethylene nonwoven fabric is made from the following raw materials by weight percentage: based on the total weight of the raw materials, the polyethylene content is 20%-50%; ultra-high molecular weight polyethylene is 1%-10%; white oil is 45%-75%; antioxidant is 1%-2%; and conductive agent is 1%-3%. The weight-average molecular weight of the polyethylene is 50,000 to 200,000; the viscosity-average molecular weight of the ultra-high molecular weight polyethylene is 500,000 to 5,000,000.

2. The polyethylene nonwoven fabric according to claim 1, wherein, The ultra-high molecular weight polyethylene has a melt index of less than 5 g / 10 min at 190°C and 2.16 kg load, preferably less than 2 g / 10 min; The conductive agent is a polyphenolic acid, which is selected from at least one of 2,5-dihydroxybenzoic acid, gallic acid, caffeic acid, ferulic acid, vanillic acid, p-hydroxycinnamic acid, rosmarinic acid, and sarsaparilla acid.

3. The polyethylene nonwoven fabric according to claim 1, wherein, The polyethylene nonwoven fabric has a fiber diameter of 1-10 μm, a thickness of 0.1-0.2 mm, an air permeability greater than 1 μm / Pa·s, and a water vapor permeability greater than 1000 g / m³. 2 • After 24 hours, the microbial barrier performance is greater than 3, and the tensile strength is greater than 5 kN / m.

4. The method for preparing polyethylene nonwoven fabric according to any one of claims 1-3, characterized in that, The preparation method includes the following steps: 1) Mix and melt the raw materials, cool and condense to obtain a gel, and break the gel into spinning particles; 2) After the spinning particles are melted and extruded, they are ejected through the die head of the spinning system. Under the coordinated stretching of the wind field and the electrostatic field, the resulting polyethylene fibers are deposited on the receiving mesh belt to form polyethylene nonwoven fabric.

5. The method for preparing polyethylene nonwoven fabric according to claim 4, wherein, In step 1), the melting conditions include stirring at 170-240℃ for 1-2 hours.

6. The method for preparing polyethylene nonwoven fabric according to claim 4, wherein, In step 2), the temperature of melt extrusion is 160-180℃, the temperature of the die head is 180-240℃, the temperature of the hot air in the air field is 200-290℃, the air field strength is 0.1-0.6MPa, and the electrostatic field strength is 5-50KV.

7. The apparatus for preparing polyethylene nonwoven fabric using the preparation method according to any one of claims 4-6, characterized in that, The preparation apparatus includes: a continuous screw extrusion spinning system, a hot air generation system, a suction system, a high-voltage electrostatic generation system, and a receiving mesh belt; According to the material flow, the receiving mesh belt is located downstream of the continuous screw extrusion spinning system, the suction system is located inside the receiving mesh belt, the hot air generation system and the suction system form an air field, and the high-voltage electrostatic generation system provides an electrostatic field. The air field and the electrostatic field work together to act on the polyethylene fibers ejected from the die of the continuous screw extrusion spinning system.

8. The apparatus for preparing polyethylene nonwoven fabric according to claim 7, wherein, The die head is a multi-hole die head or a micro die head; the aperture of the multi-hole die head is 0.2mm-0.3mm.

9. The apparatus for preparing polyethylene nonwoven fabric according to claim 7, wherein, The hot air outlet of the hot air generating system is located on the upper and lower sides of the mold head, and the electrostatic field is applied between the mold head and the receiving mesh belt.

10. The application of the polyethylene nonwoven fabric according to any one of claims 1-3 in the fields of medical breathable membrane packaging, protective clothing, construction, radiation refrigeration and filtration.

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