Continuous fiber reinforced thermoplastic rod and pultrusion method for its manufacture

Abstract

A composite rod for use in various applications, such as electrical cables (e.g., high voltage transmission cables), power umbilicals, tethers, ropes, and a wide variety of other structural members, is provided. The rod includes a core that is formed from a plurality of unidirectionally aligned fiber rovings embedded within a thermoplastic polymer matrix. The present inventors have discovered that the degree to which the rovings are impregnated with the thermoplastic polymer matrix can be significantly improved through selective control over the impregnation process, and also through control over the degree of compression imparted to the rovings during formation and shaping of the rod, as well as the calibration of the final rod geometry. Such a well impregnated rod has a very small void fraction, which leads to excellent strength properties. Notably, the desired strength properties may be achieved without the need for different fiber types in the rod.