Patent ID: 8460790

Claim:
An aggregate of nanofibers made of a thermoplastic polymer selected from the group consisting of polyethylene terephthalate, polybutylene terephthalate, poly(lactic acid), polytrimethylene terephthalate, nylon 6, nylon 66, polyolefin and polyphenylene sulfide, wherein single fiber fineness by number average is in a range from 1×10 −7 to 6×10 −5 dtex and 60%, in fineness ratio, or more of single fibers are in a range from 1×10 −7 to 6×10 −5 dtex in single fiber fineness and 50% or more, defined in terms of fineness ratio, of single fibers that constitute the aggregate of nanofibers have a diameter within a range of 30 nm in the spread of diameters of the single fibers, said aggregate of nanofibers having a morphology of a filament-yarn and/or a morphology of a spun yarn and an orientation that extends in one dimension over a definite length.