Amtek Research International LLC

Chi Thuong-Le La

Richard W Pekala

Robert R Waterhouse

James E Emanuel

Matthew Alan Warren

Cory S Rogers

Robert Waterhouse

Jeffry M Frenzel

David P Walker

A polymer fiber sheet exhibits high porosity and good tensile properties in both 'wet' and 'dry' states. A fiber modifying agent is incorporated into a polymer extrusion and fiber formation process to produce a highly porous polymer fiber sheet that is instantaneously wettable by an aqueous medium. The fiber modifying agent functions as either one or both (1) a plasticizer that reduces the polymer extrudate melt viscosity and allows the formation of fine fibers during processing and (2) a surface modifying agent that promotes the instantaneous and sustainable wettability of individual polymer fibers and a porous fiber sheet formed from them. The polymer fiber sheet maintains its wettability even after repeated washing and drying cycles. The resultant fiber sheet can be densified and embossed to provide a desired thickness and porosity, while at the same time longitudinal ribs with desired pattern can also be formed on the fiber sheet.

Instantaneously wettable polymer fiber sheet

A lead-acid battery separator with ultralow resistivity results from high porosity, controlled pore () size distribution, and an ionic surfactant () with a long alkyl side chain () that is anchored to the polymer matrix () of a silica-filled polyethylene separator. The surfactant cannot be easily removed or washed away and thereby imparts sustained wettability to the separator. Controlling the number of, and volume occupied by, the pores (i.e., porosity) and pore size distribution of the separator contributes to a reduction in electrical (ionic) resistivity.

Lead-acid battery separators with ultra low resistivity and sustained wettability

A microporous silica-filled polyolefin separator () has a material composition that includes a fraction of cured rubber powder exhibiting low or no porosity. The cured rubber powder is a material derived from one or both of passenger and truck tires. The cured rubber powders exhibit the properties of increasing hydrogen evolution overpotential on the negative lead electrode and of decreasing the effect of antimony deposited on the negative electrode of the lead-acid battery. Incorporation of these cured rubber powders into the formulation of a microporous silica-filled polyethylene separator results in improved electrochemical properties in deep-cycle lead-acid batteries.

Composite battery separator

A microporous polyethylene battery separator material (), for use in a flooded-cell type lead-acid battery, benefits from increased porosity, enhanced wettability, and exceptionally low electrical resistance when an electrolyte-soluble pore former is employed in the manufacturing process. The pore former () is soluble in electrolytic fluid and therefore dissolves in-situ in sulfuric acid during battery assembly. The dissolution of the pore former leaves behind additional, larger voids () in the separator material and thereby enhances ionic diffusion and improves battery performance.

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Happy Valley, OR, United States of America

Chi Thuong-Le La