METHOD FOR PRODUCING A HOLLOW BODY BY THE EXTRUSION AND BLOWING OF PLASTICS MATERIAL AND UNIT FOR CARRYING OUT SAID METHODS

摘要

ABSTRACT OF THE DISCLOSUREMethod for producing a hollow body by the extrusion andblowing of plastics material, comprising feeding plastics materialto an extruder and an extruding die at the outlet of which thereis obtained a parison roughly producing the shape of the hollowbody, and blowing air into the parison, thereafter introducingthis parison into a mould having a cavity whose shape correspondsto the shape of the body to be moulded, wherein, with the mouldopen, air is blown into the parison until its length is equal tothe length of the desired hollow body, then the blowing air is cutoff so as to obtain a deflated parison, the mould is closed andair at high pressure is blown into the parison so as to obtain themoulded body. This method results in a uniform thickness of theplastics material in the various cross-sections of the container.