Extrusion blow molding method for plastic containers, especially plastic bottles

Abstract

An extrusion blow-molding method for plastic containers, for example, plastic bottles, is disclosed, wherein a one- or multi-layer plastic tube is extruded with a predetermined extrusion pressure through an annular gap, which is delimited by an extrusion die provided on an extrusion head and a axially adjustable mandrel and which can be adjusted with regard to the width thereof. The extruded plastic tube is introduced into a mold cavity of a blow-molding tool arrangement, blow-molded into a plastic container in accordance with the mold cavity by overpressure and then demolded. Additional plastic material is added in metered quantity to the extruded plastic tube at least in some regions in the direct vicinity of the mouth of the extrusion die. The additional plastic material is introduced through one or more discharge nozzles distributed across the circumference with a pressure that is higher than the extrusion pressure such that the plastic material is locally compressed and that, after passing the extrusion die, the plastic tube in the regions provided with the additional plastic material has a greater wall thickness than the remaining plastic tube.