W. R. Grace Co.-conn.

The Dow Chemical Company

Minnesota Mining and Manufacturing Company

3m Innovative Properties

Victor S Chang

Joseph T Lundquist

Marc E Parham

Anthony J Laccetti

RIchard C Hartwig

John Allen Wheatley

Walter J Schrenk

James K Kung

James A Avtges

Christian B Lundsager

Richard T Giovannoni

A birefringent interference polarizer which may be fabricated from readily available materials using established coextrusion techniques is provided. The polarizer has a level of light absorption near zero and can be fabricated to polarize and reflect light of specific wavelengths while transmitting light of other wavelengths. The polarizer includes multiple alternating oriented layers of at least first and second polymeric materials having respective nonzero stress optical coefficients which are sufficiently different to produce a refractive index mismatch between the first and second polymeric materials in a first plane which is different from the refractive index mismatch between the first and second polymeric materials in a second plane normal to the first plane. The refractive index mismatch in the first plane is preferably at least 0.03.

Birefringent interference polarization

Birefringent interference polarizer

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 polysulfone polymer and a filler or polysulfone polymer and structure enhancing 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 60 volume percent composed of pores such that the average pore diameter increases from each major surface toward the interior of the sheet product's thickness.

Battery separator

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.

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 polycarbonate polymer and a filler or a polycarbonate and a structure enhancing agent, said sheet product having a porous 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 nominal pore diameter increases incrementally from each major surface towards the interior central portion of the sheet product's thickness.

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 polymer and a filler or a polymer and a structure enhancing agent and having a porous sheet embedded between the first and second major surface. The porosity of the sheet product is at least about 50 volume percent having a pore distribution such that the nominal pore diameter increases from each major surface towards the interior central portion of the sheet product's thickness.

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 thermoplastic polyurethane polymer having a high degree of hard segments with a filler or said polyurethane with a structure enhancing agent, said sheet product having a sheet embedded within said mixture and between the first and second major surfaces. The sheet product has porosity of at least about 50 volume percent composed of pores such that the nominal pore diameter increases from each major surface towards the interior, center of the sheet product's thickness.

Growing community of inventors

Ellicott City, MD, United States of America

Victor S Chang