Since entering the 21st century, the development of meltblown nonwovens technology in the world has advanced by leaps and bounds. Hills and Nordson of the United States have successfully developed two-component meltblown technology earlier, including leather core type, parallel type, triangle and so on, usually the fiber tread is close to 2μ, the number of holes of the meltblown spinnerett assembly can reach 100 holes per inch, and the extrusion amount per hole can reach 0.5g/min. Leather core type: can make the nonwovens feel soft, can be made into concentric, eccentric, special-shaped products. Generally, cheap materials are used as cores, and expensive, polymers with special or required properties are the outer skin, such as the core is polypropylene, and the outer skin is nylon to make the fiber hygroscopic; The core is polypropylene, and the outer skin is low melting point polyethylene or modified polypropylene, modified polyester, etc. that can be bonded. For carbon black conductive fibers, the conductive core is wrapped inside. Parallel type: can make the nonwovens have good elasticity, usually made of two different polymers, or the same polymer of different viscosity to make parallel two-component fibers, using different polymers different heat shrinkage can be made into spiral coiled fibers. For example, 3M has developed meltblown PET/PP two-component fiber nonwovens, which form spiral curling due to different shrinkage, so that the nonwovens have excellent elasticity. Terminal type: This is another polymer in the three-leaf type, cross type and terminal compound, such as antistatic, moisture conductive, conductive fiber can be composite on the top of the conductive polymer, both moisture conductivity, conductive and antistatic, and save the amount of conductive polymer. Micro denier type: It can be used in orange petal, strip-strip type components, or island type components. Use two incompatible polymers to peel to make microfiber networks, and even nanofiber networks, such as the peeling two-component fiber developed by Kimberly-Clark, is to use two incompatible polymers made of two-component fibers in hot water for less than a second, the two polymers can be completely peeled off to make microfiber networks. The island type dissolves the sea to obtain a fine island fiber network. Hybrid type: It is a fiber network that mixes both co-spun and two-component fibers with different materials, different colors, different fibers, different cross-sectional shapes, and even parallel fibers with leather cores, so that the fibers have the required properties. Compared with general meltblown fiber products, this kind of meltblown two-component fiber nonwovens or mixed fiber nonwovens can further improve the filterability of the filter medium, and make the filter medium have antistatic, conductive, hygroscopic, enhanced barrier, etc.; Or improve the adhesion, fluffiness and air permeability of the fiber web. Two-component meltblown fiber can supplement the lack of single polymer performance, such as polypropylene is cheaper, but if used in medical materials, it is not resistant to radiation exposure, so that polypropylene as the core, in its outer layer to choose the appropriate radiation-resistant polymer wrapped outside can solve the problem of radiation resistance. This makes the product inexpensive and fulfills functional requirements, such as heat and moisture exchangers that can be used in the respiratory system in the medical field, providing suitable natural heat and humidity. It is lightweight, disposable or easy to disinfect, inexpensive, and can also remove contaminants ...