W. R. Grace Co.-conn.

W. R. Grace Co.

Richard T Giovannoni

Robert M Spotnitz

Howard J Troffkin

Burton M Rein

Yihong Guo

Christian B Lundsager

Joseph T Lundquist

Wai Ming Choi

Marc E Parham

Anthony J Laccetti

Victor S Chang

RIchard C Hartwig

James K Kung

David Zuckerbrod

A battery separator composed of a microporous sheet product having first and second major surfaces and a thickness of less than about 50 mils, formed from a uniform mixture of a halogenated polyolefin polymer and a filler or a halogenated polyolefin polymer and surfactant/filler agent, said sheet product having a fibrous sheet embedded within said mixture and between the first and second major surfaces. The porosity of the sheet product is at least about 50 volume percent composed of pores such that the average pore diameter increases from each major surface towards the interior of the sheet product's thickness.

Battery separator

A thin microporous sheet product useful as a battery separator composed of a highly filled polymeric matrix having a porous support sheet encapsulated between the sheet product's first and second major surfaces and to a process of forming the sheet product.

The present invention is directed to a multi-ply unfilled microporous sheet product composed of at least one first ply and at least one second ply which are, respectively, formed from polymeric compositions having different rheological properties and to a method of forming said sheet product.

A process of having a microporous multiply sheet product which is capable of becoming non-porous at a predetermined elevated transformation temperature is formed by first forming a non-porous, multiply initial sheet product having at least one first ply and at least one second ply, each with its own viscosity profile. The initial sheet product is then stretched and annealed to impart porosity to the sheet product.

Process of making a battery separator

A battery separator in the form of a microporous membrane composed of a substantially uniform composition of a polymer mixture of ultra high molecular weight polyolefin, polyethylene terpolymer and polyvinyl chloride, in combination with at least one plasticizer for the polymer mixture and an inert filler.

Growing community of inventors

Columbia, MD, United States of America

Richard T Giovannoni