METHOD OF ELECTRIZATION OF NONWOVEN CLOTH, ELECTRET FILTER MEDIUM, FLEXIBLE FILTERING MASK AND BREATHING MASK ASSEMBLY Russian patent published in 1999 - IPC

FIELD: methods of electrization of nonwoven cloth used for manufacture of electret filter medium designed for breathing apparatuses and filtering masks for removal of microparticles from air. SUBSTANCE: method of electrization of nonwoven cloth made from thermoplastic microfibers consists in action on nonwoven cloth from thermoplastic nonconducting microfibers having resistivity above 10¹⁴ Ohm. cm and capable of catching a great number of charges by impacts of water jets or flow of water drops under pressure sufficient for production of electret cloth with high filtering ability. Then, cloth is dried. Electret filter medium presents nonwoven cloth from thermoplastic nonconducting microfibers having caught charge produced by acting on cloth with the help of impacts of water jets or water drops flow under pressure sufficient for obtaining the cloth possessing electret charge improving filtering and cloth drying. Flexible dome-shaped filtering mask is meant for protection of nose and moth and contains nonwoven cloth from thermoplastic nonconducting microfibers having caught charge produced by acting on cloth of water jets or water drop flow under pressure sufficient for obtaining the cloth possessing electret charge, and by cloth drying. Breathing mask assembly including face part which consists of at least one breathing hole, breathing valve and air filter, at least one discharge hole, and discharge valve, sealing member attached to face part and belts for fastening the mask to head. Air filter includes nonwoven cloth the same as in filtering mask. Nonwoven cloth made by the method possesses high filtering ability and its use is preferable on said objects. EFFECT: higher efficiency. 11 cl, 11 dwg, 4 tbl