Mechanical properties of mass-coloured polypropylene fibres

This paper describes investigations carried out into the mechanical propert ies of non-coloured and coloured PP fibres. A phtalocyanine pigment having nucleating abilities of alpha-form and a quinacridone pigment having the ab ility of nucleating beta-form were used for colouring fibres. Fibres formed at different take-up velocities and heat-stabilized fibres were investigat ed. It was found that the tenacity of fibres increases with the increase ta ke-up velocity. For coloured fibres spun at higher take-up velocities the t enacity of coloured fibres is smaller than the tenacity of non-coloured fib res. On the basis of microscopic analysis of fibre fractures it was found t hat the smaller tenacity of coloured fibres is caused by the occurrence of pigments in interfibrillar zones. Increase in tenacity and decrease in brea k elongation were observed for fibres submitted to heat stabilization.