Extruded, injection-moulded or blow-moulded plastic pipe, fitting or shaped part of plastic for making pipelines and process for manufacture of the initial composite material of the middle layer of the extruded, injection-moulded or blow-moulded plastic pipe

摘要

Extruded, injection-moulded or blow-moulded pipe, fitting or shaped part of plastic for making pipelines for liquid, pasty and gaseous media, having a pipe element made up of at least three layers with an inner layer (2) and an outer layer (3) made of a basic material and a middle layer (4) made of a basic material and at least one additive material. The inner layer (2), the middle layer (4) and the outer layer (3) of the pipe, fitting or shaped part comprise a polymer material with a polypropylene random copolymer (5) as the basic material. In particular oxidizing and reducing media are incorporated into the amorphous areas of the partially crystalline polymer of the inner layer (2) in contact with the medium to be conveyed, and wherein fillers and additives are integrated into the amorphous areas of the polymer material of the middle layer (4) as a barrier material to reduce migration of the additives from the inner layer (2) to the outer layer (3) of the pipe, fitting or shaped part. By process for manufacture of the initial composite material of the middle layer (4) of the plastic pipe, wherein a plastified polypropylene random copolymer (5) with short-cut glass fibres (6) with an initial length of 0.3 to 6 mm or with endless glass fibres crushed during the mixing process, and/or with glass balls (7) and/or with glass powder (8), and if necessary stabilizers and additives, are transformed in a compounding unit into a homogenous composite material, with the glass fibres having a tex between 500 and 5000.