POLYETHYLENE COMPOSITION WITH HIGH RESISTANCE TO STRESS CRACKING Russian patent published in 2018 - IPC C08L23/04 C08L23/08 C08F210/02 

FIELD: technological processes.

SUBSTANCE: invention relates to polyethylene composition for manufacture of geomembranes by flat-slot die extrusion, extrusion with blow-up or lamination. Composition has density of from 0.930 to 0.945 g/cm³, value of z-average molecular weight (Mz) equal to or greater than 1,500,000 g/mol, and MIF/MIP ratio from 30 to 55, where MIF is melt flow index at 190 °C with weight of 21.60 kg and has value from 3 to 25 g/10 min, and MIP is melt flow index at 190 °C weight of 5 kg. In addition, composition has index number of long chain branching not more than 0.50, where index number of long chain branching is the ratio of mean square radius of inertia of macromolecule R_g measured by method GPC-MALLS to the measured mean square radius of inertia of macromolecule of linear polymer PE having the same molecular weight.

EFFECT: polyethylene composition of the invention has suitable balance of chemical passivity, flexibility and processability in processing and high resistance to environmental stress cracking (ESCR).

10 cl, 1 dwg, 1 tbl, 2 ex