Alloys of immiscible polymers

An extrudable composition is provided which is made from at least two thermoplastic polymers in a biconstituent construction. One of the thermoplastic polymers is present as a dominant continuous phase and the other one or more polymers are present as a non-continuous phase or phases in an amount of 1.5 weight percent or less. No compatibilizer is necessary. The polymer of the non-continuous phase or phases has a polymer melt temperature higher than 30° C. below the polymer melt temperature of the continuous phase. The polymer of the dominant phase may be, for example, polypropylene and the non-continuous phase may be, for example, polyamide. The extrudable composition may be used to produce fibers which are generally between about 5 and 50 microns in diameter. The fibers may be made into nonwoven fabrics.