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US 2011/0254186 A1Published application
Ptfe membrane
AssigneeDonaldson Company, Inc.
InventorsRichard Brandimarte, Kirit Patel
Life of this patent
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Abstract
A method for improving the dimensional stability of PTFE membranes by the application of elevated temperature and elevated pressure to a PTFE membrane. The process reduces and/or eliminates the relaxation stress normally associated with PTFE membranes made using previously existing methods.
Claims20
A method of affecting the dimensional stability of a PTFE membrane, comprising:
- a) subjecting the PTFE membrane to an elevated temperature above the melting point of the PTFE membrane for a given exposure time;
- and
- b) subjecting the PTFE membrane to an elevated pressure for a given exposure time,
- wherein the PTFE membrane is simultaneously subjected to the elevated temperatures and elevated pressures, and wherein the effects on the dimensional stability are dictated at least in part by the combination of the temperature, pressure and exposure time.
1 more element
A method of processing a PTFE membrane, the comprising the steps of:
- a) providing an oriented PTFE membrane that has been at least unilaterally oriented;
- b) simultaneously subjecting the PTFE membrane to a temperature of at least 340° C. for a period of less than 1 second and a pressure of at least 1 pound per square inch.
Dependencies are inferred from the claim text.