Nucleated C3C4 copolymers and nucleated C3C4C2 terpolymers

1. A propylene butylene polymer composition comprising

A) a propylene butylene copolymer or a propylene butylene ethylene terpolymer which is

free of phthalic acid esters as well as decomposition products thereof;

obtained by a Ziegler-Natta catalyst

and

B) a nucleating mixture of at least one particulate nucleating agent and at least one soluble nucleating agent,

whereby the propylene butylene polymer composition has

a MFR (2.16 kg/210° C.) in the range of 12 to 50 g/10 min, and

a tensile modulus (measured on injection moulded test specimens in accordance with ISO 527) of more than 1200 MPa, and

a Tm of more than 150° C., and

an amount of xylene cold soluble (XCS) fraction of less than 7.0 wt.-%

and whereby the propylene butylene copolymer includes monomer units derived from

a) propylene in an amount of 91-96 wt.-% and

b) butylene in an amount of 4-9 wt.-%

with respect to the total weight of the propylene butylene copolymer,

or wherein the propylene butylene ethylene terpolymer includes monomer units derived from

a) propylene in an amount of 90-96 wt.-% and

b) butylene in an amount of 4-9 wt.-% and

c) ethylene in an amount of not more than 1.0 wt.-%

with respect to the total weight of the propylene butylene ethylene terpolymer.

2. Composition according to claim 1 , having

a content of hexane hot solubles C6 (FDA) of less than 2.5 wt.-%.

3. Composition according to claim 2 , wherein the propylene butylene polymer composition comprises the propylene butylene copolymer, and has

a tensile modulus (measured on injection moulded test specimens in accordance with ISO 527) of more than 1400 MPa, and

a Tm of at least 152° C., and

a C6 (FDA) of below 1.8 wt.-%.

4. Composition according to claim 3 having an amount of xylene cold soluble (XCS) fraction of 2.0 to 4.0 wt. -%.

5. Composition according to claim 2 , wherein the propylene butylene polymer composition comprises the propylene butylene ethylene terpolymer, and has

a tensile modulus (measured on injection moulded test specimens in accordance with ISO 527) of more than 1300 MPa, and

a Tm of at least 151° C., and

a C6 (FDA) of below 2.0 wt.-%.

6. Composition according to claim 5 having an amount of xylene cold soluble (XCS) fraction of 4.0 to 6.8 wt.-%.

7. Composition according to claim 1 having a crystallisation temperature Tc of more than 118° C.

8. Composition according to claim 1 , whereby the nucleating mixture is a mixture of (i) a trisamide or sorbitol derivative soluble nucleating agent and (ii) a polymeric particulate nucleating agent.

9. Composition according to claim 8 , whereby the amount of the trisamide or sorbitol derivative soluble nucleating agent is 500 to 10000 ppm with respect to the propylene butylene polymer composition.

10. Composition according to claim 8 , whereby the amount of the polymeric particulate nucleating agent is 10 to 3000 ppm with respect to the propylene butylene polymer composition.

11. Process for the preparation of a propylene butylene copolymer composition comprising

(A) a propylene butylene copolymer which is free of phthalic acid esters as well as decomposition products thereof and

(B) a nucleating mixture of at least one particulate nucleating agent and at least one soluble nucleating agent,

whereby the propylene butylene copolymer composition has

a MFR (2.16 kg/210° C.) in the range of 12 to 50 g/10 min, and

a tensile modulus (measured on injection moulded test specimens in accordance with ISO 527) of more than 1200 MPa, and

a Tm of more than 150° C., and

an amount of xylene cold soluble (XCS) fraction of less than 7.0 wt.-%

and whereby the propylene butylene copolymer includes monomer units derived from

a) propylene in an amount of 91-96 wt.-% and

b) butylene in an amount of 4-9 wt.-%

with respect to the total weight of the propylene butylene copolymer;

the process comprising

polymerizing propylene and butylene in a two reactors coupled in series

using a Ziegler Natta catalyst system

having citraconate as internal donor, an organoaluminum compound as co-catalyst, and an organosilane as external donor at a Al/external donor ratio of 5.0-8.0 mol/mol and a Al/Ti ratio of 190 to 240 mol/mol, and further feeding the at least one particulate nucleating agent to at least one reactor,

whereby in a first reactor a pre-polymerization is carried out at 25-35° C. for 10 to 60 minutes yielding a pre-polymer,

further polymerizing the pre-polymer at a temperature of 65-75° C., at a C4/C3 ratio of 115 to 145 mol/kmol yielding a first intermediate having an C4 content of 4 to 7 wt.-% and XCS of 2 to 5 wt.-%,

transferring the first intermediate to a second reactor and further polymerizing at 75 to 85° C. at a C4/C3 ratio of 90 to 130 mol/kmol,

to yield the second reactor product,

extruding the second reactor product in the presence of the at least one soluble nucleating agent to yield the propylene butylene copolymer composition.

12. Process for the preparation of a propylene butylene ethylene terpolymer composition comprising

A) a propylene butylene ethylene terpolymer which is free of phthalic acid esters as well as decomposition products thereof;

and

B) a nucleating mixture of at least one particulate nucleating agent and at least one soluble nucleating agent,

whereby the propylene butylene ethylene terpolymer composition has

a MFR (2.16 kg/210° C.) in the range of 12 to 50 g/10 min, and

a tensile modulus (measured on injection moulded test specimens in accordance with ISO 527) of more than 1200 MPa, and

a Tm of more than 150° C., and

an amount of xylene cold soluble (XCS) fraction of less than 7.0 wt.-%

and

wherein the propylene butylene ethylene terpolymer includes monomer units derived from

a) propylene in an amount of 90-96 wt.-% and

b) butylene in an amount of 4-9 wt.-% and

c) ethylene in an amount of not more than 1.0 wt.-%

with respect to the total weight of the propylene butylene ethylene terpolymer;

the process comprising

polymerizing propylene, butylene, and ethylene in three reactors coupled in series

using a Ziegler Natta catalyst system

having citraconate as internal donor, an organoaluminium compound, and an organosilane as external donor at a Al/external donor ratio of 5.0-8.0 mol/mol and a Al/Ti ratio of 190 to 240 mol/mol, and further feeding the at least one particulate nucleating agent to at least one reactor,

whereby in a first reactor a pre-polymerization is carried out at 25-35° C. for 10 to 60 minutes yielding a pre-polymer,

further polymerizing the pre-polymer at a temperature of 65-75° C., at a C4/C3 ratio of 115 to 145 mol/kmol yielding a first intermediate having an C4 content of 4 to 7 wt.-% and XCS of 2 to 5 wt.-%,

transferring the first intermediate to a second reactor and further polymerizing at 75 to 85° C. at a C4/C3 ratio of 80 to 120 mol/kmol to yield the second reactor product,

transferring the second reactor product to a third reactor and further polymerizing at a temperature of 75 to 85° C. at a C2/C3 ratio of 70 to 90 mol/kmol to yield a third reactor product, and

extruding the third reactor product in the presence of the at least one soluble nucleating agent.

13. The propylene butylene copolymer composition obtained by the process of claim 11 .

14. Molded article comprising the composition of claim 1 .

15. The molded article according to claim 14 , wherein the composition has a haze (1 mm plaque) of less than 23%, a FD shrinkage of less than 1.38% and a TD shrinkage of less than 1.55 and further optionally the composition has a notched impact strength (23° C.) of at least 5.0 kJ/m 2 .