Filter

Abstract

Shown is a filter in which powder aggregation (bridge) is hard to occur, and a time until a rise of differential pressure is caused is long, more specifically, a filtration life is long. The filter has a base material layer, a filtration layer and a skin layer, in which the base material layer is a layer formed by a nonwoven fabric being wound in a multiple manner, and subjected to the thermocompression bonding, the filtration layer is a layer formed by a laminate prepared by laminating at least a through-air nonwoven fabric and a net, being wound in a multiple manner, and subjected to no thermocompression bonding, the skin layer is a layer including a nonwoven fabric, and a mean pore diameter of the nonwoven fabric composing the base material layer and the skin layer is larger than a mean pore diameter of the through-air nonwoven fabric composing the filtration layer.

Dependencies are inferred from the claim text.