| 摘要 |
A cylindrical filter is formed of stacked microfine conjugate fibers comprising a higher melting point component and a lower melting point component, each obtained by a melt-blow spinning process, the fiber diameter of the conjugate fibers decreasing across the thickness of the filter and in the direction of passage of a fluid to be filtered, and the contact points of the conjugate fibers being melt-adhered by the lower melting point component. This cylindrical filter is produced by a process which comprises subjecting a higher melting point component and a lower melting point component, each consisting of a fiber-forming thermoplastic polymer, to conjugate melt-blow spinning so that the fiber diameter varies during the spinning; winding up and stacking the fibers onto a core to form a cylindrical shape on the core with the fibre diameter decreasing across the width of the stack in the direction of flow of liquid through the filter; heat-treating the resulting web at a temperature above the melting point of the lower melting point component and below the melting point of the higher melting point component, before, at the time of or after the winding-up, and drawing out the core. |
