Patent ID: 6509436
Filing Date: 2003-01-21
Classification: B32B,B65D,Y10T

Abstract:
A process for preparing polycondensation copolymers capable of absorbing oxygen comprising predominantly polyester segments and an oxygen scavenging amount of unhydrogenated polyolefin oligomer segments comprising the steps of:(a) providing an extruder having a heated mixing zone, at least one inlet port to the mixing zone, and an exit die opening; (b) feeding polyester and a transesterification catalytic amount of a transition metal carboxylate via an inlet port into the heated mixing zone of the extruder; (c) conveying an oxygen scavenging unhydrogenated polyolefin oligomer into the extruder mixing zone via an inlet port at a rate sufficient to impart oxygen scavenging capacity to the copolymer formed, wherein said polyolefin oligomer is at least singly functionally terminated with end groups capable of entering into polycondensation reactions; (d) mixing and heating the polyester, the carboxylate, and the polyolefin oligomer under an inert atmosphere at a temperature, and for a residence time in the mixing zone, sufficient to melt the polyester and cause it to react with the functionally terminated polyolefin oligomer to form polycondensation copolymer via transesterification; and (e) conveying the copolymer to the extruder exit die opening and extruding the copolymer therefrom.