Abstract: A process for the production of a wall for a package including producing a preform of the wall and stretching the preform of the wall where the preform includes a layer containing a polymer and having oxygen-scavenging properties. The preform and the stretching ratios applied are chosen (i) so that the time (t.sub.I) which the permeance of the wall for oxygen would take to rise to 1/5 of the value it would have in the absence of oxygen scavenging would be at least 10 days and (ii) if the preform were stretched at that time (t.sub.I) after the preform were produced, the time (t.sub.D) which the permeance of the wall for oxygen would take to rise 1/5 of the value it would have in the absence of scavenging would be at least 1/4 of the time (t.sub.I). The time between completion of step (A) and the commencement of step (B) is at least 10 days.

Abstract: The present invention provides a wall for a package comprising: (a) an outer set of one or more layers (1-4) and (b) an inner set of one or more layers (5-6) which layer or the outermost of which layers (5) comprises a composition comprising a polymer and having oxygen-scavenging properties, wherein (i) the outer set of layers would have, if separate from the inner set and in the absence of any oxygen-scavenging properties in any of the layers or the layer constituting the set, a permeance, for oxygen, of not more than 1.5 cm.sup.3 /(m.sup.2 atm day); (ii) the inner set of layers would have, if separate from the outer set and in the absence of oxygen-scavenging properties in any of the layers or the layer constituting the set, a permeance, for oxygen, of at least 2.0 cm.sup.3 /(m.sup.2 atm day); and (iii) the inner set of layers would have, if separate from the outer set, a permeance, for oxygen, less than the permeance specified in (ii) by at least 1.0 cm.sup.3 /(m.sup.

Abstract: The present invention provides a wall for a package, which wall comprises, or includes a layer comprising, a composition comprising a polymer and capable of scavenging oxygen through the metal-catalysed oxidation of an oxidisable organic component thereof. The oxidisable organic component is preferably itself a polymer, and may be the only polymer in the composition. Preferred compositions include a blend of 96% polyethylene terephthalate and 4% poly (m-xylyleneadipamide) containing 200 ppm cobalt as catalyst, with good permeance-versus-time performance (3) when formed into a bottle.