Abstract: To provide a filter medium that has small repulsion in pleating processing, has excellent air and water permeation resistance and filter performance, and has low pressure loss even when an adsorbent loading amount of the filter medium to be subjected to pleating processing is large, and to provide a filter element provided with the filter medium, and a method for manufacturing the filter medium. The filter medium includes an adsorptive layer interposed between air permeable substrates. At least one of the air permeable substrates has a folding streak on the inner face side thereof.

Abstract: The present invention provides a filter containing a filter material folded into a chrysanthemum shape. While such a filter can be made of an electret fiber nonwoven fabric or a fiberglass nonwoven fabric, preferably it is made of a polytetrafluoroethylene porous film that is extended lengthwise and widthwise such that the overall area is extended by more than fifty-fold.

Abstract: A method for producing graphite fiber comprising graphitizing carbon fiber having a strength of 500 kgf/mm.sup.2 or more and a modulus of elasticity of from 27,000 to 33,000 kgf/mm.sup.2, and having at least on the surface of the fibers, from 0.2 to 2% by weight of an epoxy resin as a sizing agent, from 0.005 to 0.10% by weight of silicon and 0.005 to 0.02% by weight of phosphorus based on the weight of carbon fiber having said epoxy resin, silicon and phosphorus.

Abstract: The high-strength non-woven fabric comprises 100 parts by weight of a non-woven fabric having an apparent fiber diameter of 0.1-15 .mu.m; and 0.3-10 parts by weight of an N-methylol or N-alkoxymethyl nylon resin applied to the non-woven fabric, the N-methylol or N-alkoxymethyol nylon resin being cross-linked. The high-strength non-woven fabric has high mechanical strength with small maximum pore diameter. It is suitable for battery separators.