Abstract: A preform of a thermoplastic material, especially a material which is orientable during blow forming, has an opening region, a closed bottom as well as walls connecting the bottom with the opening region. In the region of at least a part of the surface demarcating the preform a texturing enlarging the surface is provided, which has a low profile depth relative to the wall thickness of the preform. A process for heating a preform of a thermoplastic material is also disclosed which includes texturing a portion of the surface of the preform to enlarge the surface area thereof whereby the time required to heat the preform to a desired temperature suitable for blow molding is reduced. The preform is also rotated as it is moved past a heating device and the heating device is controlled such that the heating device combination with the texturing provides a desired temperature profile rendering the preform suitable for blow molding.

Abstract: To improve the properties of biaxially orientated blow-moulded containers of PET the mouth region of the container serving for fitting a closure member is heat-set, i.e. crystallized at elevated temperature. The heat-setting is effected at the mouth end of a parison or preform and the previously heat-set mouth end is then reshaped to the finished mouth portion. This improves the dimensional stability of the mouth region.

Abstract: In a process for producing hollow bodies of oriented thermoplastic material, a hollow blank having a bottom portion and a substantially cylindrical wall portion with an opening at its end remote from its bottom portion is subjected to pre-expansion in the region of the opening and then thermofixing in a subsequent treatment step. The thermofixing operation may be preceded by a mechanical expansion operation for orienting the plastic material forming the wall portion of the blank.

Abstract: A process and an apparatus for forming a flange on the wall portion of a hollow body of thermoplastic material with an opening at one end provides that the end part of the wall portion which defines the opening is heated and contracted by means of a force acting on the end portion from the outside thereof over the periphery thereof, whereupon the contracted end part is subjected to a pressing operation to form a flange extending around the contracted end part.

Abstract: A process for producing hollow bodies from oriented thermoplastic material wherein a cylindrical portion of a heated hollow preform which has a bottom thereon is subjected to stretching at a starting temperature which is below the vitreous transition temperature of the thermoplastic material, with the wall thickness of the preform being reduced in the stretching operation. Prior to the stretching operation the preform is heated in the portion in which the stretching effect begins, to a temperature higher than in the portion adjoining same. Stretching is preferably effected along the axis of the preform at different rates such that in the portion of the preform at which stretching begins, stretching is effected at a lower rate than in the portion adjoining same in the stretching direction.

Abstract: A method is disclosed for making a three layered parison for blow molding a biaxially oriented hollow article of thermoplastic material. One end portion of an extruded tubular body is heated to welding temperature and closed to a bottom by a forming step. The central layer of the multilayered body is removed from part of the end portion before the forming step takes place to insure that the central barrier layer of the body allows for an intimate welding together of the inner and outer layer. A similar operation is used in making the finish portion of a container at the opposite end of the tubular body.

Abstract: The heated end of a parison is brought into a finish mold form to shape a finish profile suitable for setting up a closure. The parison is axially stretched by a stretch pin to pull out the heated plastic material adjacent the profile to a thinner cross section. This allows to obtain a considerable saving of weight of the plastic material.

Abstract: The heated end of a parison is brought into a finish mold form to shape a finish profile suitable for setting up a closure. The parison is axially stretched by a stretch pin to pull out the heated plastic material adjacent the profile to a thinner cross section. This allows to obtain a considerable saving of weight of the plastic material.

Abstract: A method for blow molding containers and the like articles from thermoplastic parisons. The parisons are heated in two stages, i.e., in a pre-heating oven to a uniform temperature less than the blow molding temperature and by infra red radiation to a final blow molding temperature which, preferably, is non-uniform along the length of the parison. The non-uniform heating is accomplished by moving the parison axially through an annular infra red radiator at varying rates of speed. Since the degree of heating is directly proportional to the time of exposure to the radiation, a variable temperature profile can be imparted to the parison by means of a simple speed program. Such a variable temperature profile results in controlled wall thickness distribution during blow molding, and the final container is of enhanced strength and of lower weight.

Abstract: A tubular slug of thermoplastic material is preheated and is then gripped a position spaced from an open end of the slug, the gripping means being such as to effect a reduction in cross-section of the gripped portion of the slug. Such reduction in cross-section provides a shoulder which abuts the gripping means during application of pressure to the end face of the slug to deform the end portion thereof to provide a thread, groove or other profiled formation.