Melt blown nonwoven fabric (full analysis)

Technological process of melt blown nonwoven fabric

The process of melt blown nonwoven fabric: polymer feeding - melt extrusion - fiber formation - fiber cooling - Network - reinforced into cloth.
Development of melt blown nonwovens Technology: dual component melt blown Technology

Since the twenty-first Century, the development of the technology of melt blown nonwovens has developed rapidly.

The American Hills company and Nordson company has successfully developed bicomponent melt blown technology, including skin core type, parallel type, triangle and other fiber, usually close to 2µ, the number of empty wire components can be per inch 100 holes, each hole extrusion amount can reach 0.5g/min.

Skin core type: it can make the nonwoven fabric soft and can be made of concentric, eccentric and heteromorphic products. Cheap materials as a core, expensive, with special or desired properties for polymer surface layer, such as the core of polypropylene and nylon sheath is the fiber is hygroscopic; core for polypropylene, skin to low melting point polyethylene for bonding or modified polypropylene, modified polyester etc.. For carbon black conductive fibers, the conductive core is wrapped in it.

Parallel type: it can make nonwovens have good elasticity. It is usually made of two different polymers or different viscosity of the same polymer. It is made of two component fiber. It can make helical coiled fiber with different heat shrinkage of different polymers. For example, 3M developed a melted PET/PP two-component fiber nonwovens. Because of different shrinkage, it forms helical coiling, making nonwovens have excellent elasticity.

Terminal type: This is another polymer that is made of three leaf type, cross type and end compound. When conducting antistatic, moisture conducting and conductive fibers, the conductive polymer can be mixed on the top, which can not only conduct moisture, but also conduct electricity and antistatic, and save the amount of conductive polymer.

Fine denier: you can use orange - shaped, strip - shaped components, or island - type components. Peel made of superfine fiber net with two kinds of incompatible polymers, and nano fiber networks, such as Kimberly-Clark developed stripping type bicomponent fiber, is the use of two incompatible polymers made of bicomponent fiber in hot water in less than a second, two kinds of polymers can be finished all made of superfine stripping characteristics fiber net. The island type is to dissolve the sea and get a fine network of island fiber.

Mixed type: it is a network of fibers with different materials, colors, fibers, sections, and even core and core fibers. It has both common spinning and two component fibers, so that the fiber has all kinds of properties needed. This kind of filter meltblown nonwoven bicomponent fiber or hybrid fiber nonwoven fabric and melt blown fiber products compared to further improve the filter medium, and filter medium with antistatic property, conductivity, moisture absorption, enhanced barrier properties; or the fiber net bonding, fluffy, breathable to improve.

Lack of bicomponent meltblown fibers can complement the single polymer properties, such as polypropylene is cheaper, but as for the materials, it is not resistant to radiation, so you can choose the appropriate polypropylene as the core, radiation resistant polymer coated on the outside can solve the problems in the outer radiation resistance. It can make products cheap and functional requirements, such as heat and humidity exchangers, which can be used in respiratory system in medical field, and provide suitable natural heat and humidity. It is light, disposable or easy to sterilize, cheap, and can also remove the additional effect of contaminant filter. It can be composed of two kinds of evenly mixed double component melt blown fiber net. The core is a double component fiber, the core is polypropylene, and the cortex is nylon. Two component fiber can also be made of special shaped section, such as three leaf shape and multi leaf shape, so that its surface area is larger. At the same time, polymer can improve filtration performance on its surface or tip. Olefins or polyester melted double component fiber nets can be made into cylindrical liquid and gas filters. The melt spray double component fiber net can also be used in the cigarette filter Tsui, using the core absorption effect to make the high grade ink sucking core, and the core sucking rod of the liquid and the infusion.

Development of melt blown nonwovens -- melted nanofibers
In the past, the development of melted fiber was based on the patent technology of Exxon, but in recent years, many international companies have broken through the development of Exxon technology to the finer nanoscale fibers.

Hills has made a deep study of the nanoscale fiber, which is said to have reached the stage of industrialization. Other enterprises, such as Nonwoven Technologies (NTI), have also developed the technology and technology of the production of the nanoscale spray fiber, and have made a patent.
In order to spinning nano fiber spinneret spinneret than ordinary meltblown equipment on a much smaller, NTI can be used to small 0.0635mm (63.5 microns) or 0.0025 inch, spinneret module structure can be combined into a total width of 3 meters. The spun melted fiber is about 500 nanometers in diameter. The most fine single fiber diameter up to 200 nm.

The melt blown equipment for spinning nanofibers will be greatly reduced due to the small hole and no measures. Therefore, NTI should increase the number of holes in the spinneret hole, and each spinneret has 3 rows or even more rows of spinneret holes. A lot of unit components (depending on width) are combined and the output can be greatly increased during spinning. The actual situation is that when the 63.5 micron hole is used, the number of holes per row of spinneret is 2880. If the three row is used, the number of holes per meter of spinneret can reach 8640 holes, so that its output can be equivalent to that of ordinary melt blown fiber.

Because thin porous spinneret with high density is expensive and easy to break up (under high pressure and heat cracking), various companies have developed new bonding technologies to enhance the fastness of spinneret, so that they will not leak under high pressure.

At present, the nanoscale fiber can be used as a filter medium, which can significantly improve the filtration efficiency. Data also show that: due to the finer fiber in nano scale melt blown nonwovens, the lighter weight melt blown fabric and spunbond composite can be used, and it can still withstand the same head pressure. The SMS products made of it can reduce the proportion of melt blown fiber.