Patent ID: 6991850

Claim:
A yarn having a force-displacement profile such that: (a) when said yarn is subjected to an initial barrier stress of from about 0.2 gram/denier to less than or equal to about 1.4 grams/denier, said yarn elongates to less than 3 percent and the initial modulus ranges from about 20 grams/denier to about 150 grams/denier; (b) upon subjecting said yarn to greater than said initial barrier stress and less than or equal to 1.8 grams/denier, said yarn elongates further to an amount of no more than about 10 percent at less than or equal to 1.8 grams/denier, and the energy absorbed from 0 to the elongation at 1.8 grams/denier is at least about 0.0008 Joule/denier*meter; and (c) upon subjecting said yarn to greater than 1.8 grams/denier, the modulus increases sharply and said yarn elongates further until said yarn breaks at a tensile strength of at least about 5 grams/denier and a total elongation of less than 25 percent, wherein said yarn comprises a multiplicity of fibers, all of said fibers have substantially the same force-displacement profile, are made from polymers having a glass transition temperature in the range from about −10° C. about +60° C., and are not made from polybutylene terephthalate homopolymer.