Patent ID: 6645588
Filing Date: 2003-11-11
Classification: C08F,C08L,G02B,H01B,Y10T

Abstract:
A pipe comprising an inner layer and an outer layer, where the inner layer comprises an iron or steel layer, an epoxy primer and a coupling agent covering said primer, and the outer layer comprises a melt coating polymer composition which comprises a multimodal ethylene polymer, which contains from 80 to 99.8% by weight of ethylene repeating units and from 0.2 to 20% by weight of C3-C10 &agr;-olefin repeating units, has a density of between 0.941 g/cm3 and 0.955 g/cm3, and is a blend of at least a first ethylene polymer having a first average molecular weight corresponding to a melt flow rate MFR12 of from 50 g/10 min. to 2000 g/10 min. and a first molecular weight distribution and a second ethylene polymer having a second average molecular weight corresponding to a lower melt flow rate than said first ethylene polymer, wherein said blend is the product of a polymerization process comprising at least two steps in which said first ethylene polymer is prepared by polymerizing ethylene in the presence of a catalyst system in a first step and said second ethylene polymer is prepared by polymerizing ethylene in the presence of a catalyst system in a second-step, said steps being performed in any order, the ethylene polymer of each step being present in the following step or steps, the ratio between the first and second ethylene polymer being from 80:20 to 20:80, said blend having a third average molecular weight corresponding to a melt flow rate MFR32 of from 0.1 g/10 min. to 20 g/10 min. and a third molecular weight distribution.