Flame retardant polymer composition comprising polyolefin with high molecular weight distribution

1. A flame retardant polymer composition, comprising

(A) a polyolefin comprising an ethylene homo- and/or copolymer with a molecular weight distribution M w /M n of >20,

(B) a silicone-group containing compound, and

(C) an inorganic filler material,

wherein the polyolefin (A) is produced by an autoclave reactor.

2. Flame retardant polymer composition according to claim 1 wherein the amount of component (A) is from 30 to 70 wt. % of the total polymer composition.

3. Flame retardant polymer composition according to claim 1 , wherein component (A) comprises a polyolefin with a molecular weight distribution M w /M n of >25.

4. Flame retardant polymer composition according to claim 1 , wherein component (A) comprises a polyolefin with a g′ value of 0.35 or less.

5. Flame retardant polymer composition according to claim 1 , wherein component (A) comprises a polyolefin with a shear thinning index (SHI) eta 0.05 eta 300 of at least 70.

6. Flame retardant polymer composition according to claim 1 , wherein component (A) comprises a polyolefin with polar groups.

7. Flame retardant polymer composition according to claim 6 wherein the polyolefin with polar groups comprises a copolymer of alpha-olefin monomers with one or more co-monomers selected from C 1 - to C 6 -alkyl-acrylates, C 1 - to C 6 -alkyl-methacrylates, acrylic acid, methacrylic acid and vinyl acetate including ionomers thereof.

8. Flame retardant polymer composition according to claim 6 wherein the polyolefin with polar groups is present in an amount of at least 50 wt. % of the total weight of component (A).

9. Flame retardant polymer composition according to claim 1 , wherein the amount of component (B) is from 1 to 20 wt. % of the total polymer composition.

10. Flame retardant polymer composition according to claim 1 , wherein component (B) is a silicone fluid and/or gum, and/or a copolymer of ethylene and at least one other co-monomer which comprises a silicone group.

11. Flame retardant polymer composition according to claim 1 , wherein component (B) comprises polydimethylsiloxane and/or a copolymer of ethylene and vinyl-polymethylsiloxane.

12. Flame retardant polymer composition according to claim 1 , wherein the amount of inorganic filler (C) is from 20 to 60 wt. % of the total polymer composition.

13. Flame retardant polymer composition claim 1 , wherein inorganic filler (C) is neither a hydroxide nor a hydrated compound.

14. Flame retardant polymer composition according to claim 1 , wherein inorganic filler (C) comprises a carbonate, oxide and/or sulphate of an element of groups 1 to 13 of the Periodic System of the Elements.

15. Flame retardant polymer composition according claim 1 , wherein component (C) comprises a metal carbonate.

16. Flame retardant polymer composition according to claim 1 , wherein the composition further comprises

(D) a polypropylene in an amount of 0.1 to 10 wt. % with respect to the total composition.

17. Flame retardant polymer composition according to claim 16 , wherein component (D) has a MFR2 measured according to ISO 1133 at 230° C. and 2.16 kg of 0.1 to 15 g/10 min.

18. Flame retardant polymer composition according to claim 16 , wherein component (D) comprises a propylene heterophasic copolymer comprising a polypropylene homo- or copolymer as matrix polymer and an incorporated ethylene-propylene-rubber.

19. Article comprising the flame retardant polymer composition according to claim 1 .

20. Wire or cable comprising a layer made of the flame retardant composition according to claim 1 .

21. Method for extruding a flame retardant layer of a wire or a cable using the flame retardant polymer composition according to claim 1 , comprising a line speed of at least 20 m/min.