Process for manufacture of hollow bodies from synthetic materials

Claim 1

A process for manufacturing a hollow body for containing a substance, said body comprising at least principally synthetic plastic materials, at least portions of the walls of said body comprising at least three layers of different plastic materials including a synthetic thermoplastic carrier layer, a bonding layer on at least one side of said carrier layer, and at least one barrier layer bonded to said carrier layer by said bonding layer, said barrier layer comprising a material with characteristics differing from those of said carrier layer the extent that a mixture of said material with those materials of said carrier layer and said bonding layer cannot be re-used or can be re-used only to a very limited extent, said process including initially forming a premolded form and subsequently shaping said form into at least a portion of a finished product by means of pressure differential, characterized by simultaneously producing said form by co-extrusion with at least a carrier layer and a bonding layer but without a barrier layer, said carrier layer and bonding layer comprising materials which are chemically related so as to allow recycle and re-use of waste portions, shaping said form by blow molding into a finished or intermediate product with accompanying formation of waste portions for recycle and re-use, and subsequently applying at least one said barrier layer to at least a section of said product in a separate operation after said shaping.