Patent ID: 6372294
Filing Date: 2002-04-16
Classification: B29B

Abstract:
A method for the manufacture of unidirectionally fiber reinforced thermoplastic bands through pressure impregnation of a fiber strand, the method comprising:dispersing thermoplastic particles in a bath; drawing the fiber strand through the dispersion of the bath at a predetermined draw-off speed about a plurality of deflection elements for impregnating the strands with dispersed particles; drawing the strand out of the bath; drying the strand through subsequent heat treatments; and melting the particles, which are taken up during the impregnation, on the strand; wherein the dispersion of the bath is substantially held in a chemically stationary state through a continuous or periodic supply of an in-feed dispersion that has a first particle concentration that is held constant; wherein the dispersion of the bath is further substantially held in a chemically stationary state through an initial setting of a second particle concentration in the bath to a value that remains constant due only to a second particle concentration's automatic self-setting, which causes the second particle concentration to tend toward, and reach, an empirically determined stable stationary value without the use of controlling means when the draw-off speed, in-feed dispersion concentration and height of the bath level are all held constant; wherein the first and second concentrations depend in an empirically determinable manner on a thermoplastic content of the band to be achieved and on the draw-off speed; and wherein a particular value is set for the draw-off speed that is dependent upon the thermoplastic particle content of the band to be achieved and predetermined in such a manner that the first and second particle concentrations are approximately the same.