| 摘要 |
PURPOSE:To obtain a cylindrical net-like foam body having a net-like structure and different diameters of net-constituting strand without causing wear to a machinery by receiving the foam body extruded from a circular rotary die by changing the receiving speed. CONSTITUTION:A synthetic resin supplied from a material supplying gate 4 to an extrusion press is heated, melted and mixed with foaming agent in the extrusion press, extruded from a circular rotary die 6, turning at a prescribed speed, onto a low pressure zone, and a cylindrical net-like foam body 11 is formed. The foam body 11 is received by a receiving roll 8 designed capable of changing receiving speed periodically at a constant interval. A diameter of strand constituting mesh of a section of the foam body received at high speed than the normal speed is small and the mesh takes a diamond shape that a lengthwise axis of the cylindrical object is larger than an axis perpendicular to the above axis. By employing this method, it requires neither electromagnetic clutch for large-scale device and does not cause wear to the machinery. |
