Propylene copolymer for extrusion blow molded bottles

1. An extrusion blow molded article comprising at least 99 wt. % of a propylene copolymer (R-PP), based on the weight of the blow molded article, wherein the propylene copolymer (R-PP) has:

(a) a comonomer content in the range of 3.0 to 10.0 mol. %;

(b) a melt flow rate MFR 2 (230° C.) measured according to ISO 1133 in the range of 0.5 to 4.0 g/10 min;

(c) a relative content of isolated to block ethylene sequences (I(E)) in the range of 45.0 to 69.0%, wherein the I(E) content is defined by equation (I):

I

⁡

(

E

)

-

fPEP

(

fEEE

+

fPEE

+

fPEP

)

×

100

(

I

)

wherein:

I(E) is the relative content of isolated to block ethylene sequences [in %];

fPEP is the mol fraction of propylene/ethylene/propylene sequences (PEP) in the sample;

fPEE is the mol fraction of propylene/ethylene/ethylene sequences (PEE) and of ethylene/ethylene/propylene sequences (EEP) in the sample;

fEEE is the mol fraction of ethylene/ethylene/ethylene sequences (EEE) in the sample;

and wherein:

all sequence concentrations are based on a statistical triad analysis of 13 C-NMR data; and

(d) a hexane soluble content in the range of 1.8 to 5.0 wt. %, wherein the propylene copolymer (R-PP) has been produced in the presence of:

(i) a Ziegler-Natta catalyst (ZN-C) comprising a titanium compound (TC), a magnesium compound (MC) and an internal donor (ID), wherein said internal donor (ID) is a non-phthalic acid ester,

(ii) optionally a co-catalyst (Co), and

(iii) optionally an external donor (ED);

wherein said propylene copolymer (R-PP) comprises two fractions, a first propylene copolymer fraction (R-PP1) and a second propylene copolymer fraction (R-PP2), the comonomers of the first propylene copolymer fraction (R-PP1) and the second propylene copolymer fraction (R-PP2) are selected from ethylene, C 4 to C 12 α-olefin, and mixtures thereof, said first propylene copolymer fraction (R-PP1) differs from said second propylene copolymer fraction (R-PP2) in the comonomer content,

the weight ratio between the first propylene copolymer fraction (R-PP1) and the second propylene copolymer fraction (R-PP2) [(R-PP1):(R-PP2)] is 40:60 to 68:32, and

the first propylene copolymer fraction (R-PP1) has a comonomer content in the range of 1.0 to 7.0 mol % based on the first propylene copolymer fraction (R-PP1) and the second propylene copolymer fraction (R-PP2) has a comonomer content in the range of more than 4.5 to 13.0 mol % based on the second propylene copolymer fraction (R-PP2).

2. An extrusion blow molded article according to claim 1 , wherein the propylene copolymer (R-PP) has a xylene cold soluble fraction (XCS) in the range of 4.0 to 18.0 wt. %.

3. An extrusion blow molded article according to claim 1 , wherein the propylene copolymer (R-PP) has:

(a) a glass transition temperature in the range of −12 to +2° C.; and/or

(b) no glass transition temperature below −20° C.

4. An extrusion blow molded article according to claim 1 , wherein the propylene copolymer (R-PP) has:

(a) a melting temperature in the range of 135 to 155° C.; and/or

(b) a crystallization temperature in the range of 105 to 120° C.

5. An extrusion blow molded article according to claim 1 , wherein the propylene copolymer (R-PP):

(a) has 2,1 regio-defects of at most 0.4% determined by 13 C-NMR spectroscopy; and/or

(b) is monophasic.

6. An extrusion blow molded article according to claim 1 , wherein said first propylene copolymer fraction (R-PP1) differs from said second propylene copolymer fraction (R-PP2) in the melt flow rate.

7. An extrusion blow molded article according to claim 1 , wherein:

(a) the internal donor (ID) is selected from optionally substituted malonates, maleates, succinates, glutarates, cyclohexene-1,2-dicarboxylates, benzoates and derivatives and/or mixtures thereof; and

(b) the molar-ratio of co-catalyst (Co) to external donor (ED) [Co/ED] is 3 to 45.

8. An extrusion blow molded article according to claim 1 , wherein the propylene copolymer (R-PP) is produced in a sequential polymerization process comprising at least two reactors (R1) and (R2), in the first reactor (R1) the first propylene copolymer fraction (R-PP1) is produced and subsequently transferred into the second reactor (R2), in the second reactor (R2) the second propylene copolymer fraction (R-PP2) is produced in the presence of the first propylene copolymer fraction (R-PP1).

9. An extrusion blow molded article according to claim 1 , wherein the extrusion blow molded article is a bottle.

10. An extrusion blow molded article according to claim 1 , wherein the internal donor (ID) is a citraconate.