Graft polymerization, separators, and batteries including the separators
AssigneeHollingsworth & Vose Company
InventorWai Ming Choi
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Abstract
A non-woven sheet of polyolefin fibers having opposed major surfaces is disclosed. Some areas of one or both of the major surfaces are hydrophilic as a consequence of an acrylic graft polymerized with the surfaces of the fibers in those areas while the fibers in other areas of that major surface are free of the graft and, as a consequence, remain hydrophobic. A battery separator composed of at least two such non-woven sheets is also disclosed, as well as batteries having a separator composed of at least one such non-woven sheet. Also disclosed is a non-woven sheet of polyolefin fibers where opposed major surfaces of the sheet are hydrophilic as a consequence of such an acrylic acid graft, but the ion exchange coefficients of the two major surfaces are different.
Claims12
A non-woven sheet of polyolefin fibers having opposed major surfaces wherein some areas of one of the major surfaces are hydrophilic as a consequence of an acrylic graft polymerized with the surfaces of the fibers in those areas while the fibers in other areas of that major surface are free of the graft and, as a consequence, remain hydrophobic.
A non-woven sheet of polyolefin fibers having opposed major surfaces wherein both of the major surfaces are hydrophilic as a consequence of an acrylic graft polymerized with the surfaces of the fibers adjacent that surface, and wherein one of the major surface has a given ion exchange coefficient measured in milliequivalents per gram, while the other major surface has an ion exchange coefficient measured in milliequivalents per gram, that is at least 10 percent different.
A battery comprising a case, alternate negative and positive plates in said case, positive and negative terminals, suitable electrical connections among said plates and said terminals, and separator material between alternate ones of said positive and negative plates that is a non-woven sheet of polyolefin fibers having opposed major surfaces wherein some areas of one of the major surfaces are hydrophilic as a consequence of an acrylic graft polymerized with the surfaces of the fibers in those areas while the fibers in other areas of that major surface are free of the graft and, as a consequence, remain hydrophobic.
Dependencies are inferred from the claim text.