| 摘要 |
Filaments of a thermoplastic polymer which have been produced by melt-spinning the polymer (see Division B5) have a tri-lobal cross-section consisting of a central lobe and two pendant lobes, each lobe being bounded by a circular arc, the angle included at the centre of curvature of the central lobe by the lines joining the said centre to the centres of curvature of the two pendant lobes being between 80 and 120 degrees, the lobes being separated at their peripheries by arcs of inverse curvature, the two arcs between the central lobe and each of the pendant lobes being substantially identical and having larger radii of curvature than the arc between the two pendant lobes, the said cross-section having a single line of symmetry passing through the centre of curvature of the central lobe and bisecting the arc of inverse curvature between the two pendant lobes, but no other line of symmetry and no centre of symmetry, the ration of the radius of curvature of the pendant lobes to the distance from the centre of curvature of the central lobe to the centre of curvature of either of the pendant lobes being 0.60 to 1.0, and the circular arcs of the three said lobes substanding at their respective centres of curvature three angles the sum of whose magnitudes is 400 to 800 degrees. The filaments may be formed into a drawn multifilament yarn which may be crimped by a mechanical method at a temperature not below 100 DEG C., the crimped yarn cooled in the relaxed state, tensioned heated to a temperature between the second order transition temperature of the polymer and its melting point, and then cooled. The crimped yarns may be used in the manufacture of tufted carpets and like floor coverings. |
