Multi-layer microporous polyolefin membrane and battery separator
AssigneeToray Battery Separator Film Co., Ltd.
InventorsShintaro Kikuchi, Kotaro Takita, Koichi Kono
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Abstract
A multi-layer, microporous polyolefin membrane having at least three layers, which comprises first microporous layers made of a polyethylene resin for constituting at least both surface layers, and at least one second microporous layer comprising a polyethylene resin and polypropylene and disposed between both surface layers, the heat of fusion (ΔHm) of the polypropylene measured by differential scanning calorimetry being 90 J/g or more, and the polypropylene content in the second microporous layer being 50% or less by mass based on 100% by mass of the total of the polyethylene resin and the polypropylene.
Claims4
A multi-layer, microporous polyolefin membrane having at least three layers, which comprises first microporous layers comprising a polyethylene resin for constituting at least both surface layers, and at least one second microporous layer comprising a polyethylene resin and polypropylene and disposed between both surface layers, the polyethylene resin in the first and second microporous layers having a melting point of 130° C. to 140° C., the heat of fusion (ΔHm) of the polypropylene measured by differential scanning calorimetry being 90 J/g or more, and the polypropylene content in the second microporous layer being 3 to 45% by mass based on 100% by mass of the total of the polyethylene resin and the polypropylene.
A battery separator formed by a multi-layer, microporous polyolefin membrane having at least three layers, the multi-layer, microporous polyolefin membrane comprising first microporous layers comprising of a polyethylene resin for constituting at least both surface layers, and at least one second microporous layer comprising a polyethylene resin and polypropylene and disposed between both surface layers, the polyethylene resin in the first and second microporous layers having a melting point of 130° C. to 140° C., the heat of fusion (ΔHm) of the polypropylene measured by differential scanning calorimetry being 90 J/g or more, the polypropylene content in the second microporous layer being 3 to 45% by mass based on 100% by mass of the total of the polyethylene resin and the polypropylene.
Dependencies are inferred from the claim text.