3m Innovative Properties Company

Minnesota Mining and Manufacturing Company

Alan D Rousseau

Marvin E Jones

Seyed A Angadjivand

Betty Z Mei

Joel W Miller

Philip D Eitzman

Elsie Anderson Fohrenkamm

Seyed Abolhassan Angadjivand

William L Kausch

Seth M Kirk

Steven John Pachuta

Laurence W Reilly, Jr

Gerald R Spartz

Hyacinth L Cabibil

An electret article that includes a polymeric material that has electric charge imparted thereto, that has a CF:CFratio of at least 0.15 and that has a fluorosaturation ratio greater than about 200. The electret article may be in the form of a porous web of polymeric fibers suitable for use as a filter. The inventive electret article is resistant to charge degradation upon exposure to high temperatures for prolonged time periods.

Electret article having high fluorosaturation ratio

A method for imparting an electrostatic charge to a nonwoven fibrous web . The fibrous web is contacted with a liquid solution that includes water and a non-aqueous water soluble component, followed by drying . The resulting dried product is an electret article that could be used as an air filter in, for example, a respirator

Process of making a fibrous electret web

Method of making electret fibers

A method of charging fibrous webs with nonaqueous polar liquids. A web that contains nonconductive fibers is wetted with a nonaqueous polar liquid The web is then substantially dried to provide a fibrous electret web. The fibrous electret web can be used as a filter in a filtration face mask that is adapted to cover the nose and mouth of the wearer. The present method has the advantage over known charging methods in that the nonaqueous liquid requires less energy for drying than is required for aqueous liquids. Additionally, many filter webs can be directly wetted with nonaqueous liquids, which cannot be easily wetted with aqueous liquids.

Method of making a fibrous electret web using a nonaqueous polar liquid

A method for imparting an electrostatic charge to a nonwoven fibrous web . The fibrous web is wetted with a wetting liquid , followed by being saturated with an aqueous polar liquid and drying . The resulting dried product is an electret article that could be used as an air filter in, for example, a respirator

Method and apparatus for making a fibrous electret web using a wetting liquid and an aqueous polar liquid

Method of making electret fibers that have low level of extractable hydrocarbon material

Compounds useful as resin additives

Method of removing particulate solid or liquid aerosol from a gas

Novel electret articles containing a polymer and a performance-enhancing additive can be identified by their thermally stimulated conductivity characteristics or their filtration properties. Electret articles such as nonwoven filter webs and respirators exhibit superior oily mist loading performance, low penetration and a small pressure drop.

Electret articles and filters with increased oily mist resistance

A method of predicting the performance of electret filter web involves measuring the level of extractable hydrocarbon material in the web. Electret filters that have low extractable hydrocarbon levels exhibit improved filtration performance.

Predicting electret performance by measuring level of extractable hydrocarbons

Electret fibers that contain a polymeric material and a fluorochemical additive. The electret fibers have a low level of extractable hydrocarbon material. Electret filters that have low extractable hydrocarbon levels exhibit improved filtration performance.

Electret fibers and filter webs having a low level of extractable hydrocarbons

The thermally stimulated discharge current of an electret article can be used to identify electret articles that exhibit superior filtration properties. Electret filters that exhibit superior properties not achieved in similarly constructed filters contain fibers that are made from a blend of a polymer and a performance-enhancing additive. The electret filters exhibit an initial detectable DOP penetration of less than 5% and an average Min&commat;Chl of greater than 200 mg DOP as measured by DOP Filter Web Loading Test Procedure 1. These new electrets are particularly useful in a respirator.

Electret filters that exhibit increased oily mist resistance

An electret article can be made by quenching a molten blend containing a polymer and a performance-enhancing additive. The resulting low crystallinity material can be annealed and charged to produce a material for making electret filters having superior oily mist loading performance properties.

Method of making electret articles and filters with increased oily mist

A compound comprising ##STR1## wherein R.sub.f is a perfluorinated moiety which may contain one or more catenary ether oxygen atoms, Q is a linking group selected from alkylene groups having 1 or 2 carbon atoms, sulfonamido groups or combinations thereof, and R.sup.1 is a perfluoroalkyl group.

Electret filter media comprising a fibrous web of a blend of a thermoplastic resin and at least one compound or oligomer that enhances the web's electret properties.

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Stillwater, MN, United States of America

Alan D Rousseau