The structure of the PP cotton melt blown filter element is a gradually tightening structure with coarse outer fibers, fine inner fibers, loose outer layers, and tight inner layers. The unique gradient deep filtration has formed a three-dimensional filtration effect, characterized by high porosity, high retention rate, large pollutant capacity, large flow rate, and low pressure drop.
Melt blown process is a type of polymer extrusion nonwoven process that originated in the early 1950s. In order to collect radioactive particles generated during nuclear testing, the US Navy Laboratory began developing filter materials with ultra-fine filtration effects. The research results were published in 1954. The melt blown technology in China originated in the late 1950s and early 1960s, and the equipment studied was intermittent. By the late 1960s and early 1970s, the number of intermittent meltblown equipment in China had reached over 200. Between approximately 92 and 94, continuous production lines were introduced from the United States and Germany. It is estimated that there are still over 300 intermittent meltblown equipment in operation nationwide.

In theory, any thermoplastic (high-temperature melting, low-temperature curing) polymer chip raw material can be used for the production of melt blown filter elements_ workmanship Polypropylene is the most commonly used slicing material in the melt blown process. In addition, the commonly used polymer slicing materials in the melt blown I process include polyester, polyamide, polyethylene, polytetrafluoroethylene, polystyrene, and PBT EMA, EVA, etc. Olefin polymer raw materials (such as polypropylene) have a high degree of polymerization, so the heating temperature is above its melting point by 100 ° C in order to melt and spray smoothly, while polyester can melt and spray when the heating temperature is slightly above its melting point. Olefin raw materials generally do not require drying.
The structural feature of PP melt blown filter element is that the fiber fineness is relatively small, usually less than 10 microns, with most fiber fineness ranging from 1 to 4 microns.