| 摘要 |
<p>A thick layer of a first polymeric material is formed in a tubular passageway. A laminate composed of thin layers of a 2nd and a 3rd polymeric materials is then prepd. and the laminate is fed completely around the thick first layer. - Used for forming parisons for blow moulding into bottles and containers having a multilayered structure. Allows prodn. of a container in which 1 laminate layer includes scrap polymeric material another layer contains a material which has high resistance to oxygen permeability, and in which each layer is of uniform thickness and concentricity. - A pref. embodiment has outer and inner layers (103,105) of polyolefin, a scrap polymer layer (111) and adhesive layer (109,113) bonding an ethylene-vinyl alcohol copolymer oxygen barrier layer (107) to the inner layer (105) and scrap layer (111). The parison is extruded from a die having extruder elements (3,4,5) discharging into a duct (42) to form a laminate which is conveyed to a main delivery channel (40) to join to the thick polymer layer from extruder (7) to issue as a parison from nozzle (23). (Dwg.2,4/4) EPAB- EP-110493 B A process of making a multi-layer, preferably translucent plastics container, which comprises extruding in the molten state a coextrudate of a plurality of polymer layers to form therefrom a parison, and forming the parison into a container by blow moulding, wherein the parison and a container formed therefrom include at least one thermoplastic polyolefin surface layer (105), and further layers of adhesive (e.g. 109),and barrier (107) to prevent oxygen or product permeation and, said adhesive being located so as to adhere the barrier layer to at least one of the other layers, characterised in that the parison and container therefrom include at least - one layer of scrap (111) and the coextrudate is formed by providing an advancing tubular extrusion including the polyolefin layer, and while providing the said extrusion separately forming an advancing extruded laminate comprising barrier and adhesive layers and thereafter, but prior to the coextrudate finally being extruded as a whole via an orifice, bringing the laminate into confluence with the said tubular extrusion so as to surround the latter, the scrap layer being produced from a regrind of scrap of all layers of the coextrudates from the production of previous containers of the same constructions, which scrap is composed essentially of said polyolefin, barrier, adhesive and scrap. - (15pp) USAB- US4522775 A Parison of at least 3 layers is mfd. using a co-extrusion head by forming a thick layer of liquid polymer in a tubular passageway, forming liquid flow laminate of thin layers of second and third polymers in the passageway, and feeding the liquid laminate around the liquid thick layer prior to extrusion. - The polymers are pref. a polyolefin, an adhesive, and an O2 barrier respectively.</p> |
