| 摘要 |
PURPOSE:To provide a laminated sheet composed of plural sheets, free from pinhole and having excellent adhesivity and air-passability, a process for producing the laminated sheet and a filter composed of the laminated sheet. CONSTITUTION:The objective laminated sheet is composed of plural synthetic fiber sheets having different melt-starting temperatures, stacked in the order of the melt-starting temperature and laminated by sporadic welding. The weld part has concave form on the side of the sheet having low melt-starting temperature. The laminated sheet can be produced by stacking plural sheets composed of synthetic fibers having different melt-starting temperatures and welding the sheets by ultrasonic welding. In the above procedure, the sheets are arranged in the order of the melt-starting temperature from the horn side to the anvil side. The objective filter is composed of a spun-bond nonwoven cloth and a melt-blown nonwoven cloth stacked in the order of the melt-starting temperature and laminated by sporadic welding and the weld part has a concave form on the melt-blown nonwoven cloth surface at the weld part. |
