Electret filter made of fibers containing polypropylene and poly(4-methyl-1-pentene)
AssigneeMinnesota Mining and Manufacturing Company
InventorsJohn F. Reed, Marvin E. Jones
Life of this patent
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Abstract
A fibrous electret filter better sustains electret filtration enhancement upon exposure to aerosol oils when made of fibers containing polypropylene and at least one percent by weight of poly(4-methyl-1-pentene). Even better stability is attained when the poly(4-methyl-1-pentene) content of the electret filter is ten percent by weight of total polyolefin. When used as an air filter, such as in a respirator, the electret filter has surprisingly better filtration performance than does a comparable electret filter made of 100% polypropylene fibers. The electret filter can be made either of melt-blown microfibers or of fibers of fibrillated film.
Claims20
Method of removing particulate matter from a gaseous fluid comprising passing the fluid through an electret filter comprising electret fibers containing at least one percent by weight of poly(4-methyl-1-pentene).
Electret filter comprising electret fibers containing polypropylene and at least one percent by weight of poly(4-methyl-1-pentene) per 100 parts of total polyolefin.
Electret air filter element comprising polyolefin electret fibers, at least one percent by weight of the polyolefin being poly(4-methyl-1-pentene).
Dependencies are inferred from the claim text.