Process for producing hollow bodies of thermoplastics, hollow thermoplastic body and use thereof

摘要

The invented process for producing hollow bodies (30) of thermoplastics by mold blowing is carried out in such a manner, that first a tubular preform (28) is made that is extended by means of internal excessive pressure inside the blow mould (10) until it bears against the inner wall thereof. Then an auxiliary body (26) is put into the preform (28) and is located on inner surface of the extended hollow body (30) wall. The auxiliary body (26) is then joined with a holder (24) and together therewith it is put into the preform (28) and prior treatment of the hollow body (30) inner surface with a reaction medium the holder (24) is connected with the hollow body (30) wall. The auxiliary body (26)) is first maintained in a first position at a certain distance from the hollow body (30) wall and after sufficient time of the reaction medium action it is shifted with respect to the holder (24) in a second position, at which it remains at a smaller distance from the hollow body (30) wall or bears against it. The hollow body can be used as a motor vehicle tank, where the auxiliary body (26) functions as an equalizing vessel.