Patent ID: 7374796
Filing Date: 2008-05-20
Classification: B01D,Y10T

Abstract:
1. A method of making a filter medium for use in a filtering application at an application temperature comprising: providing a substrate; providing a polyimide stiffening agent in solution selected from the group consisting of polyetherimides and polybismaleimides; diluting the polyimide stiffening agent solution to approximately 5.5% solids; treating the substrate with the polyimide stiffening agent solution; curing the treated substrate; and pleating the treated substrate, after curing the treated substrate, at a temperature above the application temperature, wherein the application temperature is greater than about 375° F.; wherein the treated substrate with the polyimide stiffening agent is capable of withstanding at least 100,000 cleaning pulses at a temperature of about 375° F., a flowrate of about 1200 cubic feet per minute, and a pressure of about 60 psi.