Alloys of immiscible polymers

Abstract

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.

What is claimed is:  
     
         1 . A nonwoven fabric which is made from fibers extruded from a composition free of a compatibilizer and comprising at least two thermoplastic polymers, wherein one of said thermoplastic polymers is a polyolefin as a dominant continuous phase present in an amount between 98.5 to 99.9 weight percent, and the other one or more polymers are polyamides as a non-continuous phase or phases present in an amount between 0.1 to 1.5 weight percent, and wherein the polymer of said non-continuous phase or phases has a polymer melt temperature higher than 30° C. below the polymer melt temperature of said continuous phase.  
     
     
         2 . The fabric of    claim 1    which is dyed.  
     
     
         3 . The nonwoven fabric of    claim 1    which is made from fibers wherein said continuous phase is at least one polyolefin.  
     
     
         4 . The nonwoven fabric of    claim 1    which is made from fibers wherein the non-continuous phase or phases are substantially evenly distributed throughout said fiber.  
     
     
         5 . The nonwoven fabric of    claim 1    which is made from fibers wherein the fibers have diameters of approximately 1 to 50 microns.  
     
     
         6 . The nonwoven fabric of    claim 1    which is made from fibers which have been thermally bonded at a temperature between about 93 and about 163° C.  
     
     
         7 . The nonwoven fabric of    claim 1    which has a percent elongation of at least 50% greater than that of nonwoven fabric made from polypropylene fibers which have been bonded at a similar temperature.  
     
     
         8 . The nonwoven fabric of    claim 1    which is made by the process selected from the group consisting of spunbonding and meltblowing.  
     
     
         9 . The nonwoven fabric of    claim 3    which is made from fibers wherein the polyamides are selected from the group consisting of polyamide 6, polyamide 11, polyamide 12, and copolymers, and blends thereof.  
     
     
         10 . The nonwoven fabric of    claim 3    which is made from fibers wherein said polyolefin is selected from the group consisting of polyethylene, polypropylene, polybutylenes and copolymers, and blends thereof, and is present in an amount between 98.5 to 99.9 weight percent, said polyamide is present in an amount between 0.1 to 1.5 weight percent.  
     
     
         11 . A personal care product comprising the fabric of    claim 1   .  
     
     
         12 . An infection control product comprising the fabric of    claim 1   .  
     
     
         13 . A protective cover comprising the fabric of    claim 1   .