Minnesota Mining and Manufacturing Company

3m Innovative Properties Company

Seyed A Angadjivand

Marvin E Jones

Alan D Rousseau

Daniel E Meyer

Electret filter media comprising a nonwoven web of thermoplastic nonconductive microfibers having trapped charge, said charge provided by (1) subjecting the nonwoven web to a corona treatment, followed by (2) impingement of jets of water or a stream of water droplets on the web at a pressure sufficient to provide the web with filtration enhancing electret charge and (3) drying the web. This electret filter media may be used in a respiratory mask to provide extraordinarily good filtration properties.

Electret filter media and filtering masks that contain electret filter media

Compounds useful as resin additives

An electret filter media, and mask, that is made of a nonwoven web of thermoplastic microfibers. The thermoplastic microfibers are of substantially the same composition, are nonconductive, and have an effective fiber diameter less than about 15 micrometers. The nonwoven web also has sufficient unpolarized trapped charge to exhibit an initial filtration quality factor of at least 0.31 when measured under the DOP Penetration and Pressure Drop Test.

Electret filter media

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.

Electret filter media containing filtration enhancing additives

Fibrous webs comprising a blend of a thermoplastic resin and at least one compound or oligomer which is ##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, R is an alkyl group, R.sup.1 is a perfluoroalkyl group, R.sup.2 is an alkyl group which may be straight chain or branched and n is a number of from 2 to 40.

Fibrous webs useful for making electret filter media

A composition comprising a blend of a thermoplastic resin and at least one compound or oligomer which is ##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, R is an alkyl group, R.sup.1 is a perfluoroalkyl group, R.sup.2 is an alkyl group which may be straight chain or branched and n is a number of from 2 to 40.

Composition useful for making electret fibers

The present invention relates to a method of making a fibrous electret material which includes the steps of (1) forming a fibrous web of nonconductive thermoplastic fibers from a blend of nonconductive thermoplastic resin and an additive which is (a) a thermally stable organic compound or oligomer containing at least one perfluorinated moiety or (b) a thermally stable organic triazine compound or oligomer containing at least one nitrogen atom in addition to those in the triazine group or (c) a combination thereof; (2) impinging jets of water or a stream of water droplets onto the web at a pressure sufficient to provide the web with filtration enhancing electret charge; and (3) drying the web.

Fibrous webs having enhanced electret properties

A method of charging a nonwoven web of thermoplastic microfibers to provide electret filter media is provided. The method includes impinging on a nonwoven web of thermoplastic nonconductive microfibers capable of having a high quantity of trapped charge jets of water or a stream of water droplets at a pressure sufficient to provide the web with filtration enhancing electret charge and drying said web.

Growing community of inventors

Darlington, United Kingdom

Seyed A Angadjivand