SHORT FIBER REINFORCED HOSE - NEW CONCEPT IN PRODUCTION AND PERFORMANCE

In the reported experiments, a simple extrusion process has been developed to orient short fibers contained in a rubber stock into a transverse position on the extrudate. The hardware is no more complex or difficult to use in production than conventional hose dies, which always produce a fiber orientation parallel to the flow. This axial orientation is not useful for many products, particularly hose, whereas the system described in this paper provides the proper circumferential orientation to meet the higher hoop stress. The fiber orientation occurs in response to changes in the shape of the channel in the die. In comparison to conventional cord-reinforced hose, the short fiber system offers many advantages. Processing is simplified by the elimination of the braiding or knitting step and the cover extrusion. The short fiber process is well adapted to continuous cure. Manufacturing costs are estimated to be 12% lower than those for the same process route using a conventional hose construction. Moreover, the short fiber hose can meet performance specifications in most low-to-intermediate pressure applications. It is a unique and functional product.