POLYETHYLENE MOLDING MASS SUITABLE AS MATERIAL FOR TUBES WITH IMPROVED PERFORMANCE CHARACTERISTICS Russian patent published in 2006 - IPC C08L23/04 F16L9/12 

FIELD: polymer materials.

SUBSTANCE: polymer molding mass composed of first ethylene polymer A (55-75 wt %) and second ethylene polymer B (25-45 wt %), which is especially suitable for manufacturing thick-wall large-caliber tubes serving to transport gas or water. In particular, polymer A is copolymer of ethylene with C4-C10-α-olefin characterized by content of α-olefin from 0.2 to 5 wt % and a wide bimodal molecular weight distribution while polymer B is the same as polymer A but with different bimodal molecular weight distribution. Molding mass is further characterized by unevenly improved resistance against FNST splitting equal to at least 150 h.

EFFECT: enabled manufacture of thick-wall large-caliber tubes not accompanied with splitting or appearance of creeping problem, which tubes are further characterized by good mechanical properties and homogeneity of material.

13 cl, 1 dwg, 6 tbl, 12 ex