The structure of PP melt-blown filter is the outer fiber coarse, the inner layer fiber is fine, the outer layer is loose, and the gradual structure of the inner layers is tight. The unique gradient deep filtration forms the stereoscopic residue effect, which has the characteristics of high porosity, high interception rate, large amount of pollutant, large flow rate and low pressure drop.
The melt-spraying process is a kind of polymer extrusion nonwoven technology, originated in the early 1950s, the United States Naval Laboratory for the collection of radioactive particles produced by nuclear tests, began to develop ultra-fine filtration effect of filtration materials, published in 1954 research results. The technology of melt spraying originated in the late 50 and early 60, and the equipment studied was intermittent. By the end of 60 and the early 70, the number of Chinese intermittent spraying equipment has reached more than 200 units. About 92-94 years from the United States, Germany to introduce continuous production lines. So far, it is estimated that there are still more than 300 intermittent spray equipment operating in the country.
In theory, all thermoplastic (high-temperature melting, low-temperature curing) of the polymer chip raw materials can be used in the production process of melt-blown filter. Polypropylene is one of the most widely used slicing materials in the process of melt spraying, in addition, the commonly used polymer chips are polyester, polyamide, polyethylene, PTFE, polystyrene, PBT, EMA, Eva and so on. Olefin Polymer raw materials (such as polypropylene) polymerization degree is higher, so the heating temperature is higher than its melting point 100 ℃ or above can smooth melt spraying, and polyester heating temperature slightly higher than its melting point can be sprayed. Olefin materials generally do not need drying.
PP Melt Spray filter structure is characterized by small fiber fineness ratio, usually less than 10 microns, most of the fiber fineness between $number micron.