FIELD: chemistry.
SUBSTANCE: invention relates to polypropylene polymer composition, which has improved balance "impact resistance-rigidity" and suitable for formed products manufacturing. Composition contains a) from 50 to 90 wt % of propylene homopolymer or propylene copolymer, containing to 5% molar links, derivatives of C2-C20-alfa-olefins, b) from 5 to 25 wt % of ethylene copolymer and one or several links, derivatives of C4-C20-alfa-olefins, with content of links, derivatives of C4-C20-alfa-olefins, from 50 mol% to 92 mol % and c) from 5 to 25 wt % of copolymer of propylene and ethylene, with content of links, derivatives of propylene more than 50 mol % and less than 92 mol %. Weight ratio between ethylene copolymer(component b) and sum of component b and component c) is equal or is larger than 0.5 and smaller or equal 0.9. And component a) has polydispersibility index (PI) larger than 3, melt flow rate (MFR) larger than 1dg/min, measured at 230° C under loading 2.16 kg, and fraction, soluble in xylol at 25° C, more than 1%, it also does not contain 2,1-disturbances of location. Component b) has characteristic viscosity higher than 1.2 dl/g and lower than 6 dl/g, density within interval from 0.850 to 0.890 g/ cm3, crystallinity, expressed through melting enthalpy, lower than 25 J/g and value of copolymerisation constants product r1x r2 lower than 5. Component c) has characteristic viscocity higher than 2 dl/g and lower than 6 dl/g, density within interval from 0.850 to 0.890 g/ cm3, value of copolymerisation constants product r1xr2 lower than 1.8 and crystallinity, expressed through melting enthalpy, lower than 30 J/g.
EFFECT: creation of polypropylene composition possessing excellent rigidity, thermal stability and impact strength.
9 cl, 3 tbl
