Propylene-butene random copolymer produced in the presence of a metallocene catalyst

1. Propylene copolymer (A)

(a) comprising at least 1-butene as a comonomer;

(b) having a comonomer content in the range of 1.0 to 3.0 wt.-%;

(c) having a xylene cold soluble fraction (XCS) equal or below 2.5 wt.-%;

(d) being partially crystallized in the β-modification; and

(e) comprising a β-nucleating agent (B);

wherein the part of the copolymer (A) crystallized

(ii) in the α-modification has a melting temperature below 152° C. and/or

(iii) in the β-modification has a melting temperature below 141° C.

2. Propylene copolymer according to claim 1 , wherein the propylene copolymer (A) fulfills the equation (1.1)

[

XCS

]

[

C

]

<

1.0

(

I

⁢

.1

)

wherein

[XCS] is the amount of xylene cold soluble fraction (XCS) of the propylene copolymer (A) given in weight percent and

[C] is the amount of comonomer of the propylene copolymer (A) in weight percent.

3. Propylene copolymer according to claim 1 , wherein the propylene copolymer (A) has polydispersity index (PI) of equal or below 4.0 Pa −1 .

4. Propylene copolymer (A) according to claim 1 , wherein propylene copolymer (A) has a MFR 2 (230° C.) of not more than 0.8 g/10 min measured according to ISO 1133.

5. Propylene copolymer (A) according to claim 1 , wherein the 1-butene content of the propylene copolymer (A) is in the range of 1.0 to 2.0 wt.-%.

6. Propylene copolymer (A) according to claim 1 , wherein the propylene copolymer (A) is only constituted by propylene and 1-butene units.

7. Propylene copolymer (A) according to claim 1 , wherein the comonomer content of the propylene copolymer (A) is in the range of 1.0 to 2.0 wt.-%.

8. Propylene copolymer (A) according to claim 1 , wherein the amount of the β-modification of the propylene copolymer (A) is at least 50%.

9. Propylene copolymer (A) according to claim 1 , wherein the propylene copolymer (A) has a flexural modulus measured according to ISO 178 of at least 1000 MPa.

10. Propylene copolymer (A) according to claim 1 , wherein the propylene copolymer (A) has an impact strength measured according the Charpy impact test (ISO 179 (1eA)) at 23° C. of at least 50.0 kJ/m 2 and/or an impact strength measured according the Charpy impact test (ISO 179 (1eA)) at −20° C. of at least 2.0 kJ/m 2 .

11. Propylene copolymer according to claim 1 , wherein the propylene copolymer (A) has a full notch creep test (FNCT) measured according to ISO 16770 (at 80° C. and applied stress of 4.0 MPa) of more than 1200 h.

12. Propylene copolymer (A) according to claim 1 , which is formed into pipes or parts of pipes.

13. Process for the manufacture of a propylene copolymer (A), comprising producing the propylene polymer (A) in the presence of a metallocene catalyst and adding β-nucleated agent, and

wherein the propylene copolymer (A)

(a) comprises at least 1-butene as a comonomer;

(b) has a comonomer content in the range of 1.0 to 3.0 wt.-%;

(c) has a xylene cold soluble fraction (XCS) equal or below 2.5 wt.-%;

(d) is partially crystallized in the β-modification; and;

(e) comprises a β-nucleating agent (B);

wherein the part of the copolymer (A) crystallized

(ii) in the α-modification has a melting temperature below 152° C. and/or

(iii) in the β-modification has a melting temperature below 141° C.

14. Pipe comprising a propylene copolymer (A)

(a) comprising at least 1-butene as a comonomer;

(b) having a comonomer content in the range of 1.0 to 3.0 wt.-%;

(c) having a xylene cold soluble fraction (XCS) equal or below 2.5 wt.-%;

(d) being partially crystallized in the β-modification; and;

(e) comprising a β-nucleating agent (B);

wherein the part of the copolymer (A) crystallized

(ii) in the α-modification has a melting temperature below 152° C. and/or

(iii) in the β-modification has a melting temperature below 141° C.

15. Pipe according to claim 14 , wherein the pipe is a pressure pipe.