Process of making a battery separator
A process is described of forming a microporous multi-ply sheet product comprising (a) forming a first polymer composition and a second polymer composition; each of said compositions composed of components which are substantially inert with respect to a battery's environment for which said sheet product will be used; (b) co-extruding an initial sheet product having at least one first ply composed of the first polymer composition and at least one second ply composed of the second polymer composition; wherein each of said first ply and said second ply are bonded together and said first polymer composition exhibits a viscosity profile such that its viscosity is ultra high and substantially the same as that of the second polymer composition at temperatures of up to about 80 C and has a decrease in viscosity to exhibit flow at a transformation temperature within the range of from about 80 C to 150 C while the second polymer composition maintains its ultra high viscosity for at least 10 C above said transformation temperature; (c) imparting porosity to the initial sheet by subjecting said initial sheet to stretching and annealing; and (d) recovering the final sheet product having at least two plies comprising (1) at least one first ply in the form of a microporous sheet of a predetermined length and breadth and of less than 10 mils thickness and having pores of an average pore size of from about 0.005 to 50 microns in diameter occupying at least about 20 volume percent of said sheet, said sheet composed of a substantially unfilled first polymer composition; (2) at least one second ply in the form of a microporous sheet of a predetermined length and breadth and of less than 10 mils thickness and having pores of an average pore size of from about 0.005 to 50 microns in diameter occupying at least about 20 volume percent of said sheet, said sheet composed of a substantially unfilled second polymer composition.
- Assignee:
- W. R. Grace and Co.-Conn., New York, NY (United States)
- Patent Number(s):
- US 5240655; A
- Application Number:
- PPN: US 7-808592
- OSTI ID:
- 6108592
- Resource Relation:
- Patent File Date: 20 Dec 1991
- Country of Publication:
- United States
- Language:
- English
Similar Records
Battery separator
Battery separator
Related Subjects
BATTERY SEPARATORS
FABRICATION
ANNEALING
BONDING
MICROSTRUCTURE
POLYMERS
POROSITY
POROUS MATERIALS
SHEETS
SIZE
TRANSITION TEMPERATURE
VISCOSITY
HEAT TREATMENTS
JOINING
MATERIALS
PHYSICAL PROPERTIES
THERMODYNAMIC PROPERTIES
250903* - Energy Storage- Batteries- Materials
Components
& Auxiliaries