Sewage pipe comprising beta nucleated polypropylene material with improved properties

1. Polypropylene composition comprising

(a) a propylene homopolymer (A) comprising, at least 97 wt.-% propylene units,

(b) a platelet-like inorganic filler (B) in an amount of 0.2 to 0.8 wt.-%, based on the total polypropylene composition, and

(c) a β-nucleating agent (C) in an amount of 0.005 to 0.5000 wt.-%,

wherein

(i) the propylene homopolymer (A) has a polydispersity index (PI) of at least 4.0,

(ii) the propylene homopolymer (A) has an MFR 2 (230° C.) of less than 3.0 g/10 min measured according to ISO 1133, and

(iii) the amount of β-modification of the propylene homopolymer (A) is in the range of 60 to 90% determined by DSC run according to ISO 3146/part 3/method C2 using second heat scan.

2. Polypropylene composition according to claim 1 , wherein the platelet-like inorganic filler (B) has α-nucleating activity.

3. Polypropylene composition according to claim 1 , wherein said platelet-like inorganic filler (B) is talc.

4. Polypropylene composition according to claim 1 , wherein said composition and/or the propylene homopolymer (A) is (are) not cross-linked.

5. Polypropylene composition according to claim 1 , wherein said composition and/or the propylene homopolymer (A) has(have) a branching index g′ of at least 0.90.

6. Polypropylene composition according to claim 1 , wherein said composition does not comprise an elastomeric polymer.

7. Polypropylene composition according to claim 1 , wherein said propylene homopolymer (A) is the only polymer component within said polypropylene composition.

8. Polypropylene composition according to claim 1 , wherein

(a) the amount of β-modification of the polypropylene composition is in the range of 65 to 85% determined by DSC run according to ISO 3146/part 3 /method C2 using second heat scan,

and/or

(b) the polypropylene composition has a polydispersity index (PI) of at least 4.5.

9. Polypropylene composition according to claim 1 , wherein said propylene homopolymer (A) is an isotactic propylene homopolymer.

10. Polypropylene composition according to claim 1 , wherein said propylene homopolymer (A) has an MFR 2 (230° C.) of below 1.0 g/10 min measured according to ISO 1133.

11. Polypropylene composition according to claim 1 , wherein said propylene homopolymer (A) has a weight average molecular weight (M w ) of at least 500.000 g/mol.

12. Polypropylene composition according to claim 1 , wherein said polypropylene composition and/or said propylene homopolymer (A) has (have) a xylene soluble fraction of at least 1.3 wt.-% determined according to ISO 6427 as stated in the example section.

13. Polypropylene composition according to claim 1 , wherein said propylene homopolymer is present within the total composition of at least 85 wt.-%.

14. Polypropylene composition according to claim 1 , wherein said β-nucleating agent (C) is selected from the group consisting of N,N′-dicyclohexyl-2,6-naphthalene dicarboxyamide, quinacridone types, pimelic acid calcium salt and mixtures thereof.

15. Polypropylene composition according to claim 1 , wherein said polypropylene composition has an impact strength measured according to the Charpy impact test (ISO 179(1eA)) at −20° C. of at least 6.5 kJ/m 2 .

16. Polypropylene composition according to claim 1 , wherein said polypropylene composition has a flexural modulus measured according to ISO 178 of at least 1800 MPa.

17. The polypropylene composition according claim 1 , used in the production of pipes, wherein a product produced from said polypropylene composition is pipes.

18. Pipe, comprising a polypropylene composition comprising,

(a) a propylene homopolymer (A) comprising, at least 97 wt.-% propylene units,

(b) a platelet-like inorganic filler (B) in an amount of 0.2 to 0.8 wt.-%, based on the total polypropylene composition, and

(c) a β-nucleating agent (C) in an amount of 0.005 to 0.5000 wt.-%,

wherein

(i) the propylene homopolymer (A) has a polydispersity index (PI) of at least 4.0,

(ii) the propylene homopolymer (A) has an MFR 2 (230° C.) of less than 3.0 g/10 min measured according to ISO 1133, and

(iii) the amount of β-modification of the propylene homopolymer (A) is in the range of 60 to 90% determined by DSC run according to ISO 3146/part 3/method C2 using second heat scan.

19. Polypropylene composition according to claim 1 , wherein said composition and/or the propylene homopolymer (A) has(have) a branching index g′of at least 0.95.

20. Polypropylene composition according to claim 1 , wherein said propylene homopolymer is present within the total composition of at least 95 wt.-%.

21. Polypropylene composition according to claim 1 , wherein said polypropylene composition has a flexural modulus measured according to ISO 178 of at least 2000 MPa.

22. Process for the manufacture of a polypropylene composition comprising:

(a) producing a propylene homopolymer (A) including at least 97 wt.-% propylene units,

(b) treating said obtained propylene homopolymer (A) with a platelet-like inorganic filler (B), in an amount of 0.2 to 0.8 wt.-%, based on the total polypropylene composition, and subsequently

(c) treating the mixture of step (b) with a β-nucleating agent (C) in an amount of 0.005 to 0.5000 wt.-%; or

producing a propylene homopolymer (A) including at least 97 wt.-% propylene units,

(b) treating the propylene homopolymer (A) of step (a) with a β-nucleating agent (C) in an amount of 0.005 to 0.5000 wt. % at temperatures in the range of 175 to 300° C.,

(c) treating said obtained mixture of step (b) with a platelet-like inorganic filler (B), in an amount of 0.2 to 0.8 wt.-%, based on the total polypropylene composition, and subsequently

(d) optionally cooling and crystallizing the polypropylene composition; or

(a) producing a propylene homopolymer (A) including at least 97 wt.-% propylene units in a multistage process, and

(b) treating said obtained propylene homopolymer (A) with a β-nucleating agent (C) in an amount of 0.005 to 0.5000 wt.-% and with a platelet-like inorganic filler (B), in an amount of 0.2 to 0.8 wt.-%, based on the total polypropylene composition, and wherein

(i) the propylene homopolymer (A) has a polydispersity index (PI) of at least 4.0,

(ii) the propylene homopolymer (A) has an MFR 2 (230° C.) of less than 3.0 g/10 min measured according to ISO 1133, and

(iii) the amount of β-modification of the propylene homopolymer (A) is in the range of 60 to 90% determined by DSC run according to ISO 3146/part 3/method C2 using second heat scan.

23. The process according to claim 22 , further comprising the steps of extruding the polypropylene composition to form a pipe.