| 摘要 |
PURPOSE:To improve release resistance, by increasing the adhesiveness between a semipermeable membrane and the fusion bonded part of a support by forming a recessed part or a small piercing hole to the fusion bonded part of a cylindrical semipermeable membrane support of which the overlapped part was sealed by an ultrasonic welding method. CONSTITUTION:To a cylindrical support for a semipermeable membrane which is formed by folding a tape like nonwoven fabric or fabric comprising polyester in a cylindrical form and sealing the overlapped part of said fabric by an ultrasonic welding method, an escape wheel having a small projection provided to the circumference thereof is arranged in the support so that the projected position of said wheel coincides with the position of the overlapped part to be pressed thereto form the outside under pressure and the support is slid to continuously form a recessed part or small piercing holes to the overlapped part in the longitudinal direction. By this method, anchoring effect is applied to the membrane and the overlapped part of the support to strongly and closely adhere the membrane and the support and release strength can be enhanced.
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