POLYPROPYLENE COMPOSITIONS, ESPECIALLY THOSE SUITABLE FOR MANUFACTURING TUBES

FIELD: polymer materials. ^ SUBSTANCE: invention relates to polypropylene composition comprising 1 to 70% filler along with propylene homopolymers or propylene block copolymers or mixtures thereof, which are propylene polymers undergone beta-crystallization induced by nucleation agents. Propylene homopolymers are characterized by melt index from 0.05 to 15 g/10 min at 230°C/2.16 kg. Propylene block copolymers contain 90.0-99.9 wt % propylene and 0.1-10 wt % alpha-olefins with 2 or 4 to 18 carbon atoms and are characterized by melt index from 0.05 to 20 g/10 min at 230°C/2.16 kg. Propylene homopolymers subjected to beta-crystallization are further characterized by IRtau values > 0.9, modulus of stretching elasticity >= 1300 MPa at 23°C, and Sharpey impact resistance >= 3 kJ/m2 at -20°C obtained in impact cam cut tests. Propylene block copolymers subjected to beta-crystallization are further characterized by IRtau values > 0.9, modulus of stretching elasticity >= 900 MPa at 23°C, and Sharpey impact resistance >= 5 kJ/m2 at -20°C obtained in impact cam cut tests. Filler is selected from group including talc, calcium carbonate, glass bills, mica, wollastonite, wood flour, zinc oxide, barium sulfate, clay, and mixtures thereof. According to differential scanning calorimetry method, beta-crystalline phase constitutes >= 30% of the composition. Polypropylene composition is used in manufacture of tubes, sheets, fittings, and containers for transportation of optionally pressurized fluids: gas or liquid, such as drinking, effluent, or waste water. ^ EFFECT: improved impact resistance, rigidity, and relative elongation of polymeric material. ^ 11 cl, 4 ex