An impregnator for impregnating a fabric layer comprising: a chamber, the chamber being structured and arranged so as to retain a binding composition in a fluid state; a first opening being structured and arranged so as to allow the fabric layer entering the chamber in a dry state from a top portion of the chamber to be dived into the binding composition; and a second opening extending along the longitudinal axis of a bottom portion of the chamber, the second opening being structured and arranged to allow the fabric layer to exit from the bottom portion of the chamber in an impregnated state, the second opening comprising a first lip structured and arranged to be in contact with a first surface of the fabric layer and a second lip structured and arranged to be in contact with a second surface of the fabric layer.