NONWOVEN FILTER MATERIAL Russian patent published in 1999 - IPC

FIELD: nonwoven filter materials for suspensions, mainly of acid and alkali nature. SUBSTANCE: filter material includes skeleton cloth and fibrous layer made from thermoplastic staple fibres laid on one or both sides of skeleton cloth. Skeleton cloth and fibrous layer are fastened together by piercing with needle and heat treatment. Skeleton cloth is made in form of needle- pierceable heat treated nonwoven material consisting of thermoplastic fibers. Bundle of fibres formed in the course of securing the skeleton cloth and fibrous layer pass from skeleton cloth to fibrous layer and from fibrous layer to skeleton cloth. Skeleton cloth contains fibres whose linear density exceeds linear density of fibrous layer. Surface of fibrous layer directed towards flow being filtered includes partial fuse fibres. EFFECT: enhanced stability and improved filtering characteristics. 5 cl, 2 dwg, 3 ex