| 摘要 |
The prevent invention addresses the problem of providing a multilayer filter medium for a filter having low pressure loss and high collection efficiency, a method for producing the same, and an air filter not only having low pressure loss and high collection efficiency but also being excellent in pleatability and wind-pressure deformation resistance. The multilayer filter medium for a filter as a means for resolution is obtained by laminating a wet-laid nonwoven fabric layer (2) on a wet-laid nonwoven fabric layer (1). The wet-laid nonwoven fabric layer (1) includes a nanofiber A having a single-fiber diameter within a range of 200 to 800 nm and a fiber length within a range of 0.4 to 0.7 mm, a fiber B having a greater single-fiber diameter than the nanofiber A, and a binder fiber C. The wet-laid nonwoven fabric layer (2) includes a nanofiber A having a single-fiber diameter within a range of 200 to 800 nm and a fiber length within a range of 0.4 to 0.7 mm, a fiber B having a greater single-fiber diameter than the nanofiber A, and a binder fiber C, the weight proportion of the nanofiber fiber A being greater than in the wet-laid nonwoven fabric layer (1). |
