A method for in situ surface modification of injection moulded polymers

A method for forming an injection moulded component from a host polymer (18) uses a very small quantity of an additive (32) that is efficiently driven to the surface of the component during the injection moulding process. The additive exists in the host polymer at a very low concentration in the bulk, much lower than would be necessary to achieve the modification in a homogeneous blend. The additive is an insoluble liquid in the host polymer under the temperature and pressure conditions of injection moulding. The additive is driven to the flow front surface (22) during injection moulding and then translated to the surface (24) of the component by fountain flow and is distributed on the surface in a thin layer, producing the desired surface modification, without altering the properties of the bulk polymer, and eliminating post processing steps from the manufacturing process.