Abstract: The dirt-repellent monofilament with a toughness of at least 36 cN/tex and an extension of under 44% has a soiling index A1>2 after five soiling and cleaning cycles. To manufacture the dirt-repellent monofilaments, a copolymer with a melting point of 255.degree. to 275.degree. C. and consisting of alkenes and perfluoroalkenes is added to a polymer melt of polythylene terephthalate before extrusion. The dirt-repellent monofilament is advantageously used in the manufacture of cleaning filters for the dry section of a paper machine, i.e. paper machine fabric filters. It may also be used to produce fabrics for general use as technical fabrics which have to be cleaned in difficult conditions.

Abstract: The soil-repellent monofilament for paper machine wire-cloths consists of at least 85% by weight of polyethylene terephthalate having a viscosity index (V.I.) of at least 96 dl/g and an added copolymer prepared from alkenes and perfluoroalkenes having a melting point from 255.degree. to 275.degree. C. To make the soil-repellent monofilament 1.5 to 5% by weight of tetrafluoroethylene is included by addition to the polymer melt of polyethylene terephthalate prior to extrusion. The soil-repellent monofilament produced by this method has a soiling index of <2 after 5 soiling and cleaning cycles.