Polypropylene fibers and fabrics

A nonwoven fabric having a fabric basis weight of not more than 15 gsm and comprising polypropylene fibers having a dpf value of 0.3 to 5 dpf, wherein said polypropylene fibers comprise a propylene polymer composition comprising at least 50 mol % propylene, said polymer composition having:

• a) a melt flow rate (MFR, ASTM 1238, 230° C., 2.16 kg) of about 10 to 25 dg/min
• b) a dimensionless Stress Ratio/Loss Tangent Index R2 [defined by Eq. (8)] at 190° C. from 1.5 to 30
• c) an onset temperature of crystallization under flow, Tc,rheol, (as determined by SAOS rheology, 1° C./min as described below, where said polymer has 0 wt % nucleating agent present), of at least about 123° C. and
• d) an average meso run length determined by 13C NMR of at least about 55 or higher.

A nonwoven fabric having a fabric basis weight of not more than 15 gsm and comprising polypropylene fibers having a dpf value of 0.3 to 5 dpf, wherein:

• said nonwoven fabric is obtainable by spun-bonding with a production line speed of at least 400 m/min;
• said polypropylene fibers are composed of a propylene polymer composition comprising at least 50 mol % propylene, said polymer composition having:
• a) a melt flow rate (MFR, ASTM 1238, 230° C., 2.16 kg) of about 10 to 25 dg/min
• b) a dimensionless Stress Ratio/Loss Tangent Index R2 [defined by Eq. (8)] at 190° C. from 1.5 to 30
• c) an onset temperature of crystallization under flow, Tc,rheol, (as determined by SAOS rheology, 1° C./min as described below, where said polymer has 0 wt % nucleating agent present), of at least about 123° C. and
• d) an average meso run length determined by 13C NMR of at least about 55 or higher;
• and
• said fabric has a ratio of CD elongation to CD peak Strength of 40 or more (when measured at speed of 200 mm/min, 100 mm gauge length) and a CD strength of 1.0 N/5 cm/gsm or more (when measured at speed of 100 mm/min, 200 mm gauge length).

A polypropylene fiber comprising a propylene polymer comprising at least 50 mol % propylene, said polymer having:

• a) a melt flow rate (MFR, ASTM 1238, 230° C., 2.16 kg) of about 10 dg/min to about 21.5 dg/min;
• b) a dimensionless Stress Ratio/Loss Tangent Index R2 [defined by Eq. (8) herein] at 190° C. from about 1.5 to about 28;
• c) an onset temperature of crystallization under flow, Tc,rheol, (as determined by SAOS rheology, 1° C./min as described herein, where said polymer has 0 wt % nucleating agent present), of at least about 131° C.;
• and
• d) an average meso run length determined by 13C NMR of at least about 97 or higher.