Patent ID: 8790492

Claim:
A method of manufacturing a fiber web, the method comprising: forming a fiber mixture; forming a resin formulation; non-compressively adding the resin formulation to the fiber mixture prior to drying the fiber mixture; and drying the fiber mixture with the resin formulation to form a fiber web, wherein the fiber web has a dust holding capacity of greater than about 3 mg/cm 2 when a pressure drop across the fiber web reaches 1,500 Pa, the fiber web has an initial fractional efficiency of greater than about 50% for particles approximately 0.3 microns in size, and the fiber web has a thickness of less than about 30 mils, wherein the dust holding capacity and the initial fractional efficiency are measured by Palas filtration performance according to ISO Procedure 5011:2000 with a test face velocity of 20.0 cm/sec and using SAE fine dust at a dust mass concentration of 200.0 mg/m 3 .