▎ 摘　　要

NOVELTY - High-strength microfiber shielding material, is claimed. The shielding material is a double-layer/three-layer composite structure, the double-layer composite structure includes an outer support layer and a filter layer, and the three-layer composite structure includes inner and outer two-layer support layers and a middle filter layer, it has a microbial barrier, the fiber diameter of the filter layer is 200 nm 7 μm, the fiber diameter of the support layer is 10 50 μm, the thickness is 100-700 μm, the tensile strength MD is 4.8-7 kN/m, CD 5-6.5 kN/m, burst resistance 575-1500 kPa, tear resistance 1000-4000 mN, air permeability 1.5-100 mm/s, hydrostatic pressure 100-200 cm H2O, particle barrier rate > 99.9%. USE - The high-strength microfiber shielding material is used as a sterile medical device packaging material or a medical protective product material (claimed). ADVANTAGE - The high-strength superfine fiber shielding material has high strength, high stiffness, high barrier and excellent performance, good ventilation property and waterproof performance, and is capable of blocking blood splashing and fine dust particles, shielding various microorganisms, avoiding influence of environmental factors. The method is convenient to operate, safe risk is low, no sewage and waste gas discharge, energy-saving and environment-friendly, no solvent volatilization, no harm body the operator, low cost and stable and continuous production, and can avoid sharp piercing, waterproof and ventilating, durable. DETAILED DESCRIPTION - High-strength microfiber shielding material, is claimed. The shielding material is a double-layer/three-layer composite structure, the double-layer composite structure includes an outer support layer and a filter layer, and the three-layer composite structure includes inner and outer two-layer support layers and a middle filter layer, it has a microbial barrier, the fiber diameter of the filter layer is 200 nm 7 μm, the fiber diameter of the support layer is 10 50 μm, the thickness is 100-700 μm, the tensile strength MD is 4.8-7 kN/m, CD 5-6.5 kN/m, burst resistance 575-1500 kPa, tear resistance 1000-4000 mN, air permeability 1.5-100 mm/s, hydrostatic pressure 100-200 cm H2O, particle barrier rate > 99.9%; where, the support layer comprises a high-strength, high-stiffness one-component or two-component non-woven fabric with a grammage of 20-80 g/m2, made of polyethylene terephthalate, polyethylene or polypropylene particles, and it is prepared by adding homogenized nanofibers, nucleating agents, light stabilizers, antioxidants, antistatic agents, antifungal agents, and white oil as auxiliary raw materials; the filter layer is made of superfine fibers with a grammage of 20-80 g/m2, including melt-blown polypropylene superfine fibers, polytetrafluoroethylene superfine fiber membranes, two-component segmental segmented spunbonded spunlace superfine fibers. An INDEPENDENT CLAIM is included for method for preparing the high-strength ultrafine fiber shielding material, comprising (i) using mechanical stress to grind the nanofibers, changing the surface crystal structure, improving the surface inertia, and preparing homogeneous nanofibers; (ii) preparation of support layer mainly composed of polyethylene terephthalate, polyethylene or polypropylene particles, adding homogenized nanofibers and nucleating fibers prepared in step (i), white oil, fully stirring evenly, so that the surface of the particles evenly adheres to the homogeneous nanofiber, nucleating agent and white oil, and after blending and melting, extruding the long fiber network structure from the spinneret; among them, the spinneret diameter of the hole is 0.3-0.6 mm; the magnetic field is set at the spinneret with a strength of 0.3-0.9 T; the temperature of the heating tunnel is 80-120°C; and the longitudinal draft ratio is 10-30 times; (iii) preparation of filter layer: mainly prepared by mixing melt-blown polypropylene ultrafine fibers, polytetrafluoroethylene ultrafine fibers, and spunlace ultrafine fibers; melt-blowning polypropylene ultrafine fibers by heating melt spinning method; polytetrafluoroethylene ultrafine fibers are prepared by melt extrusion combined with bidirectional stretching and shaping; spunlace ultrafine fibers are prepared by spunbonding process combined with spunlace method; (iv) post-treatment of support layer and filter layer: pretreating the support layer and filter layer in a drying tunnel at 80-120°C; where a group of pressing rollers heat-press each layer separately; and (v) heat-compression compounding: support layer and filter layer treated are tightly compounded by applying air-permeable adhesive and then heat-pressing or directly using at least two sets of pressure rollers to obtain a ultrafine fiber shielding material with high stiffness, high strength, and high barrier; in the above steps, step (iii) can be carried out simultaneously with step (i) in advance or in sequence, and then step (ii); or after completion after step (i), step (ii) and step (ii) are carried out at the same time/in no particular order.