Method and apparatus for forming elongate PTFE material and PTFE material particularly dental floss

摘要

An elongate PTFE material is formed by passing an unsintered PTFE tape across a heated surface in sliding contact therewith while applying tension to the tape, such that the PTFE tape, when its temperature is raised by contact with the heated surface, is longitudinally stretched with simultaneous width and thickness reduction while in contact with the surface. PTFE tapes having different properties, e.g. coefficients of friction at opposite faces can be produced. Such tapes are suitable for use as dental flosses.