METHODS FOR PRODUCTION OF POLYETHYLENE AND COMPOSITIONS THEREOF Russian patent published in 2017 - IPC C08F10/02 C08F2/34 C08L23/06 C08L23/08 

FIELD: chemistry; manufacturing technology.

SUBSTANCE: invention relates to compositions for production of polyethylene for moulding by extrusion, casting and blowing hollow articles and to a method for production thereof. Composition contains first polyethylene and second polyethylene, produced in any order in presence of a Ziegler-Natta catalyst in series-connected gas-phase reactors. At least one of first or second gas-phase reactors comprises first and second polymerisation zones, in which hydrogen pressure in first and second polymerisation zones differs so at least part of ethylene from second cycle, through first and second polymerisation zones, and gas mixture from each polymerisation zone partially or completely does not enter another zone. First polyethylene and/or second polyethylene additionally contains one or more comonomers in amount of 0.05–1.2 wt% with respect to total weight of composition and selected from olefins with formula CH₂=CHR, where R is an alkyl or substituted alkyl containing 1 to 12 carbon atoms.

EFFECT: obtained polyethylene compositions have such balanced properties as manufacturability, high degree of swelling of extruded melt with high surface quality, stability of dimensions, possibility of moulding from melt at high values of shear rate, as well as environmental stress cracking resistance (ESCR).

15 cl, 1 dwg, 3 tbl, 2 ex