Polypropylene flexifilamentary fiber containing 0.1 to 10 weight percent of an organic spreading agent and nonwoven fabric made therefrom

A nonwoven fabric composed of a fibrillated polypropylene three-dimensional plexifilamentary fiber containing an organic spreading agent, wherein said nonwoven fabric has

• a microwave birefringence in a cross section of 0.09 or more,
• a difference between a lengthwise direction and a transverse direction of the microwave refractive index in a plane of 0.02 or less, and
• a variation ratio of laser beam transmission intensity of 150% or less, and
• said three-dimensional plexifilamentary fiber has a long period scattering intensity ratio of 5 or more and includes 0.1 wt % to 10 wt % of an organic spreading agent wherein said spreading agent is an organic phosphate, organic carboxylate, sorbitol derivative, aliphatic hydrocarbon, higher fatty acid, higher fatty acid alcohol, fatty acid amide, fatty acid ester, metallic soap, polyethylene resin, polyacetal resin, polybutylene terephthalate resin, hydroxy-di(tertiary butylbenzoic acid) aluminum, p-tertiary butyl sodium benzoate, sodium benzoate, 1,3,2,4-diparamethyl-dibenzylidene sorbitol, 1,3-parachlordibenzylidene-2, 4-parachlorbenzylidene-D-sorbitol, 1,3,2,4-dibenzylidene sorbitol, phenyl sodium phosphate, high-density polyethylene, polycapramide, or polybutyl terephthalate.