The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Aug. 24, 1999
Filed:
Dec. 02, 1997
Jeffery Allen Oxley, Naperville, IL (US);
Thomas Danko, Woodridge, IL (US);
Viskase Corporation, Chicago, IL (US);
Abstract
A curl resistant battery separator of a noncellulosic nonwoven substrate extrusion coated on at least one surface with a cellulose film and process for making such separator by contacting a nonwoven noncellulosic textile substrate with a cellulose or cellulose derivative solution on at least one side of said substrate; converting the solution to a solid cellulose or cellulose derivative, preferably having a degree of polymerization of at least 350, more preferably at least 600, to form a coated substrate; washing said substrate in an aqueous solution; drying the coated substrate under biaxial tension to provide a battery separator having a moisture content of from about 4 to 25 wt. % based on the bone dry gauge of the separator(BDG); and then holding the separator for at least 8 hours at elevated temperatures of at least 40.degree. C. in the presence of a controlled amount of moisture to produce a separator which is stabilized against curling and has a moisture content between about 4 to 25 wt. % BDG and, preferably having a absorption rate of at least 6 mm/5 min. and a 30% KOH absorption of at least 200 g/m.sup.2.