Apparatus and method for impregnating fibrous strands with plastic

Abstract

An apparatus for impregnating fibrous strands with plastic material as matrix material including: an impregnating core having an outer limiting surface; an impregnating shell defining a cavity therein having an inner limiting surface, the impregnating shell completely enveloping the impregnating core and being disposed with respect to the impregnating core such that the limiting surfaces together define an impregnating channel therebetween, the limiting surfaces concentrically enclosing the impregnating channel along a joint symmetry axis such that the impregnating channel has a ring-shaped cross section in a plane transverse to the joint symmetry axis, the ring-shaped cross section having an outside dimension which diminishes by stages in a flow direction for the impregnation, feeding channels for the fibrous strands and the matrix material being defined at an intake side of the impregnating channel and a discharge opening for impregnated fibrous strands being defined at an exit side of the impregnating channel; and a plurality of expanding elements disposed on the limiting surfaces along the impregnating channel in the flow direction for the impregnation. A method for producing long fiber reinforced plastic materials or unidirectionally fiber reinforced profiles involves the use of the above apparatus in conjunction with an extruder or a pultrusion plant, respectively.