FIBERS MADE FROM POLYETHYLENE COMPOSITIONS AND METHOD OF MAKING THE SAME

摘要

The instant invention is a polyethylene composition, method of producing the same, fibers made therefrom, and method of making the same. The polyethylene composition according to instant invention comprises: (a) less than or equal to 100 percent by weight of the units derived from ethylene; and (b) less than 20 percent by weight of units derived from one or more α-olefin comonomers. The polyethylene composition according to instant invention has a density in the range of 0.920 to 0.970 g/cm3, a molecular weight distribution (Mw/Mn) in the range of 1.70 to 3.5, a melt index (I2) in the range of 0.2 to 1000 g/10 minutes, a molecular weight distribution (Mz/Mw) in the range of less than 2.5, vinyl unsaturation of less than 0.1 vinyls per one thousand carbon atoms present in the backbone of the composition. The process for producing the inventive polyethylene composition comprises the steps of: (1) (co)polymerizing ethylene and optionally one or more α-olefin comonomers in the presence of a hafnium based metallocene catalyst via a gas phase (co)polymerization process in a single stage reactor; and (2) thereby producing the polyethylene composition having a density in the range of 0.920 to 0.970 g/cm3, a molecular weight distribution (Mw/Mn) in the range of 1.70 to 3.5, a melt index (I2) in the range of 0.2 to 1000 g/10 minutes, a molecular weight distribution (Mz/Mw) in the range of less than 2.5, vinyl unsaturation of less than 0.1 vinyls per one thousand carbon atoms present in the backbone of the composition. The fibers according to the instant invention comprise a polyethylene composition comprising: (a) less than or equal to 100 percent by weight of the units derived from ethylene; and (b) less than 20 percent by weight of units derived from one or more α-olefin comonomers; wherein the polyethylene composition has a density in the range of 0.920 to 0.970 g/cm3, a molecular weight distribution (Mw/Mn) in the range of 1.70 to 3.5, a melt index (I2) in the range of 0.2 to 1000 g/10 minutes, a molecular weight distribution (Mz/Mw) in the range of less than 2.5, vinyl unsaturation of less than 0.1 vinyls per one thousand carbon atoms present in the backbone of the composition. The process for making a fiber according to instant invention comprises the steps of: (1) selecting a polyethylene composition comprising: (a) less than or equal to 100 percent by weight of the units derived from ethylene; and (b) less than 20 percent by weight of units derived from one or more α-olefin comonomers; wherein the polyethylene composition has a density in the range of 0.920 to 0.970 g/cm3, a molecular weight distribution (Mw/Mn) in the range of 1.70 to 3.5, a melt index (I2) in the range of 0.2 to 1000 g/10 minutes, a molecular weight distribution (Mz/Mw) in the range of less than 2.5, vinyl unsaturation of less than 0.1 vinyls per one thousand carbon atoms present in the backbone of the composition; (2) spinning the polyethylene composition into a fiber; and (3) thereby forming the fiber.