Method for shaping a polymer mixture into a block with a stable shape and size

Method for shaping an elementary block of stable shape and size from fragments of a polymer mixture which is compressed and constrained under a load into a defined volume of a hydraulic press (1), comprising at least one dead volume delimited by a first moving platen (3) moved into end of travel by a piston (4) and a fixed platen (2) constituting the end wall of the press, so as to form a bale of compacted fragments of a polymer mixture which is transpierced by spikes (8) heated to a temperature above the softening point of at least one of the polymers of the aforementioned mixture, wherein spikes (8), carried by a second moving platen (9) arranged with respect to the first moving platen (3), on the other side of the fixed platen (2) forming the end wall of the press (1), are made to penetrate, via orifices provided through the fixed platen. (2) forming the end wall of the press, into the bale of polymers previously compacted in the dead volume of the press, during or after compression.