COMPOSITE FIBERS AND A FILTER ELEMENT USING THE SAME

摘要

Polyolefin/polyester composite fibres having a low apparent Young's modulus are produced by composite spinning a polyolefin as sheath component and a polyester as core component; stretching the resulting unstretched filaments to two or more times their original length at a temperature 20 DEG C or more above the secondary transition point of the polyester and below the melting point of the polyolefin; and annealing the resulting stretched filaments at a temperature 20 DEG C or more above the secondary transition point of the polyester and below the melting point of the polyolefin for 30 seconds or more, to give composite fibres having an apparent Young's modulus of 210 Kg/cm<2> or less. The fibres are used to make filter elements by winding them on to a core while heating them to the melt-adhesion temperatue of their sheath component; adjusting the void content to a desired rate; and cooling the remaining core.