| 摘要 |
PROBLEM TO BE SOLVED: To provide a filter material with excellent function and biodegradable property by forming a layer which units nonwoven fabric A and B made of biodegradable fibers with a specified average fiber diameter in the filter material. SOLUTION: Nonwoven fabric A and nonwoven fabric B are made of biodegradable fibers with 0.1-10μm average fiber diameter and 10-70μm average fiber diameter, respectively. The fabric A and the fabric B are produced by forming fiber web by a dry method such as a carding method, an aerating method, a wet method, or a direct method such as a spun bonding method and then employing solely water flow twisting method or needle punching method or in combination of both methods. The fabric A and the fabric B are united while employing water flow, a needle punch, an adhesive, or thermal deposition or combining these means. A filter material comprising the fabric A, the fabric B, and the uniting layer may be in a flat plate-like state and is preferably treated by pleating process to give a wide filtration surface area and heightened collecting efficiency. The excellent property of the filter material can be retained based on the combination of the high collecting efficiency of the nonwoven fabric A and the high dust adsorptive capacity, the rigidity, and the strength of the nonwoven fabric B and after used, the filter material can be discarded to the nature and decomposed.
|
