POLYOLEFIN COMPOSITIONS WITH HIGH RUPTURE RESISTANCE Russian patent published in 2007 - IPC C08L23/10 C08L23/16 C08F2/00 

FIELD: polymer materials.

SUBSTANCE: polyolefin composition suitable for preparing single-layer membrane-type roofing coatings containing (A) from about 15 to 40% crystalline propylene copolymer with at least one α-olefin described by formula H₂C=CHR¹, where R¹ represents hydrogen or linear or branched C₂-C₈-alkyl, constituted by about 90% propylene and characterized by solubility in xylene at ambient temperature lower than about 15%; (B) from about 60 to about 85% elastomer fraction containing (1) propylene/ethylene copolymer containing from about 20 to about 35% ethylene and characterized by solubility in xylene at ambient temperature higher than about 70%; intrinsic viscosity of xylene-soluble fraction higher than about 3.0 dL/g and (2) ethylene copolymer with at least one α-olefin described by formula H₂C=CHR², where R² represents hydrogen linear or branched C₂-C₈-alkyl, constituted by about 15 to 40% α-olefin and characterized by solubility in xylene at ambient temperature higher than about 25%, intrinsic viscosity of xylene-soluble fraction within the range from about 0.5 to about 5.0 dL/g, weight ratio (1)/(2) being within the range between 1:5 and 5:1. Polyolefin composition of invention preferably obtained via consecutive polymerization in at least three steps is characterized by that by tensile strength ≥ 25 MPa, relative elongation at rupture ≥ 25 MPa and impact elasticity ≥ 150 MPa.

EFFECT: improved strength characteristics.

14 cl, 5 tbl