During multi-component moulding, different materials are extruded in succession (sequential extrusion) or above one another (coextrusion) to create products with partially differing properties, e.g. hard/soft components for stability and compensation of movements in different directions. Coextrusion allows demands to be satisfied that one material alone cannot fulfil, such as e.g. permeation or conductivity.

The advantage lies in the use of sometimes expensive plastics at defined points of the product where conventional plastics can no longer satisfy the demands.