| abstract |
An elastic fiber or film prepared from a composition comprising at least one block copolymer containing at least two polymeric blocks containing predominantly monoalkenyl aromatic hydrocarbon monomer units having a weight-average molecular weight within the range from about 4,000 to about 50,000 and at least one polymeric block containing predominantly hydrogenated conjugated diolefin monomer units having a weight-average molecular weight within the range from about 10,000 to about 200,000, a relatively low molecular weight polymer selected from the Group consisting of anionic styrene homopolymers, alpha -methylstyrene homopolymers, hydrogenated styrene, copolymers of alpha -methylstyrene and styrene and mixtures thereof and may contain a wax. In particularly preferred embodiments, the elastic fiber or film will contain at least one A-B-A triblock copolymer and an A-B' diblock copolymer. In even more preferred embodiments, the elastic fibers or films will contain at least two A-B-A triblock copolymers and at least one A-B' diblock copolymer. In the even more preferred embodiments, the first of the A-B-A triblock copolymers will have A polymeric blocks having a weight-average molecular weight within the range from about 5,000 to about 9,000 and B polymeric blocks having weight-average molecular weights within the range from about 30,000 to about 50,000 and the second of the A-B-A triblock copolymers will have A polymeric blocks having weight-average molecular weights within the range from about 4,000 to about 7,000 and B polymeric blocks having weight-average molecular weights within the range from about 55,000 to about 90,000. The A-B' diblock will, in these even more preferred embodiments, have A polymeric blocks having weight-average molecular weights within the range from about 4,000 to about 9,000 and B' polymeric blocks having a weight-average molecular weight within the range from about 13,750 to about 67,500. The elastic fibers may be prepared using any of the methods known in the prior art including melt blowing. The elastic films may be used to prepare elastic articles of manufacture. The fibers and films may be used immediately or directly after preparation in the production of the desired product or products. |