Propylene-Based Copolymers, A Method Of Making The Fibers And Articles Made From The Fibers
Patent #: 7,101,622
Inventor(s): Andy Chang, Hong Peng, Jozef Van Dun, Randy Pepper, Edward Knickerbocker, Antonios Doufas, Rajen Patel, Lizhi Liu, Byron Day, Stephen Englebert, Joy Jordan, Renette Richard, Christian Sanders and Varunesh Sharma
Company: Dow Global Technologies Inc.
An extensible fiber comprising a propylene copolymer has been patented. The copolymer comprises at least about 50 weight percent of units derived from propylene and at least about 5 weight percent of units derived from a comonomer other than propylene. The fiber is characterized as having a crystallinity index less than 30% and a modulus of less than or equal to about 22 g/den. The extensible fiber can be characterized by having a retained load of more than or equal to about 2.5% and an immediate set of less than or equal to about 22% as determined in a 50% 1-cycle test. The 50% 1-cycle test is one in which a load on the fiber is measured while the fiber is extended at a rate of 10 inches per minute to an elongation of 50% then retracted to an elongation of 0% at a rate of 10 inches per minute and then extended a second time to an elongation of 50% at a rate of 10 inches per minute. The retained load is the load measured at 30% elongation during retraction divided by the load measured at 30% elongation during the first extension. The immediate set is the elongation at which a positive load is first measured during the second extension.
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