The structure of the PP meltblown filter element is that the outer layer fiber is thick, the inner layer fiber is fine, the outer layer is loose, and the inner layer is tightly tapered to gradually tighten the structure. The unique gradient deep filtration forms a three-dimensional filter residue effect, featuring high porosity, high rejection rate, large dirt holding capacity, large flow rate and low pressure drop.
The melt-blown process is a kind of extrusion process of polymer extrusion. It originated in the early 1950s. The US Naval Laboratory began to develop filter materials with ultra-fine filtration effect to collect radioactive particles generated by nuclear tests. Published research results in the year. China's melt-blown technology originated in the late 1950s and early 1960s, and the equipment studied was intermittent. By the end of the 1960s and early 1970s, the number of batch melt-blown equipment in China had reached more than 200. Continuous production lines were introduced from the United States and Germany around the year 1992-94. So far, it is estimated that there are still more than 300 intermittent melt blown equipment in operation nationwide.
In theory, all thermoplastic (high-temperature melting, low-temperature curing) polymer chipstock materials can be used in the production process of melt-blown filter elements. Polypropylene is one of the most used slicing materials in the melt-blown process. In addition, the polymer slicing materials commonly used in the melt-blown process are polyester, polyamide, polyethylene, polytetrafluoroethylene, polystyrene, PBT, EMA. , EVA, etc. The olefin polymer raw material (such as polypropylene) has a high degree of polymerization, so that the heating temperature is higher than the melting point of 100 ° C to be melted at a higher temperature, and the polyester heating temperature is slightly higher than the melting point of the melt blowing. Olefinic feedstocks generally do not require drying.