the invention concerns a process and an apparatus for the production of hollow bodies from thermoplastic material , the wall of which is in the form of a laminate , by extrusion blow molding . tubular preforms for making the hollow bodies are first produced in an intermittent mode of operation , the wall thereof also being in the form of a laminate which includes a suitable number of layers . within an extrusion head having an annular storage chamber for receiving the laminate - formation preform and an annular piston for emptying the storage chamber , the flows of material for forming the layers of the laminate of the preform are passed through the annular piston into the storage chamber in which they combine to form the laminate . the width of the outlets at which the flows of material issue from the annular piston can be so selected that it is proportional to the thickness of the respective layers to be formed therefrom in the laminate produced in the storage chamber .