| 摘要 |
<p>The present invention consists of an inventive process for manufacturing a PTFE filament (7) of the type comprising steps of extrusion, and, subsequently, stretching, heating and cutting, and an inventive PTFE filament obtained by this process, are provided. The process of the present invention comprises the following steps prior to extrusion: providing a recipient, which preferably consists of a cylinder (1) of a pre-form machine, having rigid side walls; arranging a first mixture (A) containing PTFE filler,and a second mixture (B) containing PTFE, inside the recipient, side by side and aligned with the side walls; and pressing the first and second mixtures in a direction parallel to the side walls to form a billet (5) in which the first and second mixtures (A, B) have different coefficients of friction. After these steps, the billet (5) is extruded to form a strand (6), which is subsequently stretched, heated, rolled and cut by known processes in the art to form the inventive PTFE filament, which comprises one side with a filler and the other side without filler, so that these sides have different coefficients of friction. Also, in a preferred embodiment, the filament presents each side with a different color.</p> |
