Multilayer film

1. A multilayer film comprising a core layer (C) and two outer layers (O-1, O-2) sandwiching the core layer, wherein

(i) the core layer (C) comprises from 90 to 100% by weight of a first bimodal ethylene/1-butene/C 6 -C 12 -alpha-olefin terpolymer having a density between >925 kg/m 3 and 970 kg/m 3 with respect to the total weight of the layer,

(ii) the two outer layers (O-1) and (O-2) each comprise a blend of

(ii-1) the first bimodal terpolymer as defined for the core layer (C) and

(ii-2) a second bimodal ethylene/1-butene/C 6 -C 12 -alpha-olefin terpolymer having a density between >910 kg/m 3 and <925 kg/m 3 .

2. The multilayer film according to claim 1 , wherein the first bimodal ethylene/1-butene/C 6 -C 12 -alpha-olefin terpolymer of the core layer comprises

(A-1) a low molecular weight homopolymer of ethylene and

(A-2) a high molecular weight terpolymer of ethylene, 1-butene, and a C 6 -C 12 -alpha-olefin.

3. The multilayer film according to claim 2 , wherein the first bimodal ethylene/1-butene/C 6 -C 12 -alpha-olefin terpolymer comprises a low molecular weight fraction of a homopolymer of ethylene and a high molecular weight fraction of a terpolymer of ethylene, 1-butene, and a C 6 -C 12 -alpha-olefin,

wherein the first bimodal terpolymer has a melt flow rate MFR 21 according to ISO 1133 (190° C.) of 10 to 40 g/10 min, a density according to ISO 1183, (method A) of 910 to 950 kg/m 3 , and a comonomer content of 1 to 7% by mol whereby

the low molecular weight fraction of the first bimodal terpolymer has a melt index MFR 2 according to ISO 1133 (190° C.) of 200 to 800 g/10 min, a density according to ISO 1183, (method A) of 940 to 980 kg/m 3 , and a comonomer content of 0 to 2.5% by mol, and the amount of the low molecular weight fraction in the bimodal terpolymer is in the range of 30 to 60 wt %.

4. The multilayer film according to claim 3 , wherein the first bimodal terpolymer has a melt flow rate MFR 21 according to ISO 1133 (190° C.) of 15 to 30 g/10 min and/or a density according to ISO 1183, (method A) of 925 to 937 kg/m 3 and/or a comonomer content of 1.5 to 3.0% by mol.

5. The multilayer according to claim 3 , wherein the low molecular weight fraction of the first bimodal terpolymer has a melt index MFR 2 according to ISO 1133 (190° C.) of 300 to 600 g/10 min and/or a density according to ISO 1183, (method A) of 945 to 975 kg/m 3 and/or a comonomer content of 0 to 2% by mol and/or the amount of the low molecular weight fraction in the first bimodal terpolymer is in the range of 35 to 50 wt %.

6. The multilayer film according to claim 1 , wherein the C 6 -C 12 alpha-olefins of the first and second bimodal ethylene/1-butene/C 6 -C 12 -alpha-olefin terpolymer are selected from the group of 1-hexene, 4-methyl-1-pentene, 1-octene, and 1-decene.

7. The multilayer film according to claim 1 , wherein the first bimodal terpolymer (ii-1) of the outer layers (O-1) and (O-2) has with an MFR 2 according to ISO 1133 (190° C.) of 0.1 to 5 g/10 min.

8. The multilayer according to claim 7 , wherein the first bimodal terpolymer of the outer layers (O-1) and (O-2) has an MFR 2 according to ISO 1133 (190° C.) of 0.2 to 3 g/10 min.

9. The multilayer film according to claim 1 , wherein the first bimodal terpolymer (ii-1) of the outer layers (O-1) and (O-2) has a density according to ISO 1183, (method A) of >925 to 970 kg/m 3 .

10. The multilayer according to claim 9 , wherein the first bimodal terpolymer of the outer layers (O-1) and (O-2) has a density according to ISO 1183, (method A) of 927 to 939 kg/m 3 .

11. The multilayer film according to claim 1 , wherein the second bimodal terpolymer (ii-2) of the outer layers (O-1) and (O-2) has an MFR 2 according to ISO 1133 (190° C.) of 0.7 to 6 g/10 min.

12. The multilayer according to claim 11 , wherein the second bimodal terpolymer of the outer layers (O-1) and (O-2) has an MFR 2 according to ISO 1133 (190° C.) of 1 to 3 g/10 min.

13. The multilayer film according to claim 1 , the second bimodal terpolymer (ii-2) of the outer layer (O-1) and (O-2) has a density according to ISO 1183, (method A) of 921 to 923 kg/m 3 .

14. The multilayer according claim 13 , wherein the second bimodal terpolymer of the outer layers (O-1) and (O-2) has a density according to ISO 1183, (method A) of 915 to 922 kg/m 3 .

15. The multilayer film according to claim 1 , wherein each blend of the outer layers (O-1) and (O-2) comprise 1 to 50 wt % of the first bimodal terpolymer and >50 to 99 wt % of the second bimodal terpolymer.

16. The multilayer according to claim 15 , wherein each blend of the outer layers (O-1) and (O-2) comprises 20 to 40 wt % of the first bimodal terpolymer and 60 to 80 wt % of the second bimodal terpolymer.

17. The multilayer film according to claim 1 , wherein the outer layers (O-1) and (O-2) may be the same.

18. The multilayer film according to claim 1 , having a thickness of to 250 microns whereby the outer layers and core layer may all be of equal thickness or alternatively each outer layer forms 10 to 35% of the total thickness of the multilayered film and the core layer forms 30 to 80% of the total thickness of the multilayered film.

19. The multilayer according to claim 18 , having a thickness of 20 to 200 microns and/or each outer layer forms 15 to 30% of the total thickness of the multilayered film and/or the core layer forms 40 to 70% of the total thickness of the multilayered film.

20. A heavy duty shipping sack and/or or form-fill-seal bag comprising the multilayer film of claim 1 .