A process for the preparation of a simulated in situ polyethylene mixture

摘要

A process comprising: (i) providing a first polyethylene, prepared independently, having a melt index of 5 to 3000 grams per 10 minutes and a density of 0.900 to 0.975 grams per cm3 and a second polyethylene, prepared independently, having a flow index of 0.01 to 30 grams per 10 minutes and a density of 0.860 to 0.940 grams per cm3, the weight ratio of the first polyethylene to the second polyethylene being from 75:25 to 25:75; (ii) blending the first polyethylene with the second polyethylene; (iii)melting the blend; and, prior to extrusion or pelletizing; (iv) passing the molten blend through one or more active screens, in the case of two or more active screens positioned in series, each active screen having a micrometer (micron) retention size in the range of 2 to 70, at a mass flux of 350 to 7000 grams per hour per cm3 (5 to 100 pounds per hour per square inch).