Fibres and nonwoven prepared from polypropylene having a large dispersity index

1. A process for the production of fibers and filaments comprising:

(a) polymerizing propylene and one or more optional comonomers in presence of a Ziegler-Natta catalyst and an organoaluminium compound to produce a polypropylene having a molecular weight distribution M w /M n of at least 7;

(b) feeding the polypropylene to an extruder;

(c) subsequently melt-extruding the polypropylene to obtain a molten polypropylene stream;

(d) extruding the molten polypropylene stream of step (c) through a number of fine capillaries of a spinneret, thus obtaining filaments of molten polypropylene; and

(e) subsequently reducing the diameter of the filaments obtained in the previous step to a final diameter, wherein the polypropylene produced in step (a) is either a propylene homopolymer or a random copolymer of propylene with one or more comonomers, said comonomers being ethylene or a C 4 -C 10 alpha-olefin, said random copolymer comprising up to 6% by weight of comonomer, relative to the total weight of the random copolymer; and wherein the Ziegler-Natta catalyst comprises a titanium compound, which has at least one titanium-halogen bond, and an internal donor, both supported on a magnesium halide in active form, with the internal donor comprising at least 80 wt %, with respect to the total weight of the internal donor, wherein the internal donor is a di-ketone or a enamino-imine.

2. The process of claim 1 , wherein the polypropylene has an isotacticity of at least 97%, as measured by mmmm pentads determined by 13 C-NMR analysis.

3. The process of claim 1 , wherein in step (a) propylene and one or more optional comonomers are polymerized in further presence of an external electron donor.

4. The process of claim 1 further comprising:

(a1) thermally or chemically degrading the polypropylene produced in step (a) from a first melt flow index MFI 1 to a second melt flow index MFI 2 , such that the ratio of first to second melt flow index, MFI 2 /MFI 1 , is at least 2, with the melt flow index being measured according to ISO 1133 at 230° C. and 2.16 kg.

5. The process of claim 4 , wherein the polypropylene is thermally degraded.

6. The process of claim 4 , wherein the polypropylene is chemically degraded by bringing the polypropylene into contact with a peroxide.

7. The process of claim 1 , wherein the filaments obtained in step (e) are not subjected to a further drawing step.

8. The process of claim 1 , further comprising:

(f) collecting the filaments obtained in step (e) on a support: and

(g) subsequently bonding the collected filaments to form a bonded nonwoven.

9. The process of claim 8 further comprising:

(h) laminating a film to the bonded nonwoven obtained in step (g).

10. The process of claim 8 , wherein the nonwoven is a spunbond nonwoven.