Multistage process for producing hollow plastic articles from half shells

A process for producing hollow plastic articles, comprising the following steps:

• a) producing, by means of extrusion or coextrusion, a tubular plastic parison comprising at least one layer made from polymeric materials;
• b) cutting open the tubular plastic parison to give two planar-surface parts by means of a suitable cutting device, and using driven floating rollers for guiding of the parison over the cutting device;
• c) molding the planar-surface parts in two mold halves to give half shells, where a removable intermediate frame separates the mold halves from one another, at least along the peripheral edges, wherein the planar-surface parts and half shells are not in contact with one another;
• d) opening the mold halves and removing the intermediate frame;
• e) closing the mold halves, with the result that the half shells come into contact with one another along a peripheral rim;
• and
• f) welding the half shells.

A hollow plastic article produced by process comprising:

• a) producing a tubular plastic parison by means of extrusion or coextrusion:
• b) cutting open the tubular plastic parison to produce two planar-surface parts:
• c) molding the planar-surface parts in two mold halves to give half shells, where a removable intermediate frame separates the mold halves from one another at least along peripheral edges, wherein the planar-surface parts and half shells are not in contact with one another;
• d) opening the mold halves and removing the intermediate frame;
• e) closing the mold halves, wherein that the half shells come into contact with one another along a peripheral rim;
• and
• f) bonding the half shells.