The invention comprises a group of hollow modules through which the material to be extruded flows, comprising at least: a rectangular heating-shaping module (6), in which the material undergoes a temperature increase and takes on the desired shape; and a tubular cooling-solidification module (8), in which the material, which has taken on the desired shape, changes from liquid to solid with said shape. A heating-reaction module (2) is provided upstream of module (6), and the material to be extruded undergoes a first temperature increase in said module (2). The heating-reaction module (2) comprises an interchangeable hollow tube (3) with an external heating system (4), inside which the material to be extruded undergoes the first temperature increase. The heating-shaping module (6) comprises detachable parts (7) and includes another external heating system (4) for producing a new temperature increase by means of the auto-acceleration of the curing reaction and of the heat supply from said system (4) which may be at a higher temperature than the previous one. The tubular portion between module (2) and module (6) includes a shaping coupling (5) equipped with a through-hole. The extrusion module comprises a circuit through which the polymer flows into at least two push compartments (20).