| 摘要 |
<P>PROBLEM TO BE SOLVED: To solve the problem associated with a prior art filter medium for use in a cylindrical filter, of having an insufficient uniformity in its filtration capability caused by unevenly wound fibers or tapes constituting a cylinder or by an uneven surface appearing upon forming a cylinder by directly winding nonwoven fabric, which uneven surface results from overlaying nonwoven fabric of poor texture and an uneven thickness inherent thereto. <P>SOLUTION: Nonwoven fabric 1 constituted of a fiber having a low melting point and a fiber having a high melting point and/or a fiber not having a melting point is first subjected to preheating at a temperature of 30 to 50°C, is subsequently subjected to drying b at a temperature of 70 to 90°C to remove moisture absorbed therein if the nonwoven fabric 1 comprises a hygroscopic fiber such as rayon and nylon, is finally subjected to pressing c on a heated plate or a rotary roll reheated in a range of up to +10°C above the melting point of the fiber of a low melting point to make the surface thereof smooth, and is directly wound around a core member 2 to produce a filter medium 3 for use in a cylindrical filter, having excellent surface smoothness with the interface of the layers of the nonwoven fabric 1 sufficiently thermally bonded. The core member 2 is subsequently extracted, and the filter medium 3 removed of the core member 2 is slit by an intended length in the width direction thereof. <P>COPYRIGHT: (C)2012,JPO&INPIT |
