a container of polyethylene terephthalate or similar thermoplastic material has a container body , a mouth portion and a central bottom part . the central bottom part consists of chiefly amorphous and / or thermocrystallized material and forms a bulge directed towards the interior of the container . a ring - shaped or band - shaped standing surface is arranged adjacent the transition of the bottom part into the container wall . adjacent to the standing surface the container has a circumferential area of material which through stretching and / or reshaping has undergone flow and through heating has acquired built - in stresses which tend to contract it . the surrounding circumferential area of material prevents the inward bulge of the central bottom part from straightening out and / or turning inside out when the pressure in the container is increased and / or when the temperature of the container material is raised . the invention also relates to a method and a device for achieving the container .