Mould tool induces selective local anisotropy in low viscosity plastic mouldings

摘要

The mould tool is pressure injected with thermoplastic of low viscosity, 20-140 Pas, pref. 40-90 Pas. These may contain particulate filling, orientable filling and reinforcement, to 5-70 wt.%, pref. 20-50 wt.%. The hollow mould orientates the injection cpd. before it sets, to produce local anisotropy. In a novel arrangement, the flow entering from injection points or lines is controlled by the mould. Flow deflection in predetermined directions is achieved by narrowing the cross-section in specific regions. In addition or alternatively, such regions are momentarily closed off and subsequently opened to flow, during the course of injection. Also claimed are (i) a plastic moulding from the mould described; and (ii) a method as described, with multicoloured injection, including cores.