Apparatus for molding multilayered articles

摘要

An apparatus for injection molding two compatible polymeric materials, in which two substantially coaxial extrusion screws are used to plasticize the two materials into a common accumulation space. The charge comprising multiple layers of material is then injected into a closed mold by means of forward axial motion of the outer screw with respect to its enclosing barrel. Once inside the mold, the first material forms a skin layer totally or partially surrounding the other material. In this way a part having a plurality of material properties may be produced in a single operation.