| 摘要 |
PURPOSE:To manufacture stably a foam which is free from bending or a crack also and possesses fine and uniform bubbles, by a method wherein a brake is arranged in the way between a cooling sphere of a die and a heating furnace and a movement of a partly-foamed molded body to a downstream side is controlled. CONSTITUTION:Thermoplastic resin, a foaming agent and a crosslinking agent which are inevitable ingredients are mixed up evenly with each other and a resin composition in a fixed composition is regulated in an extruding machine 1. The resin composition extruded through an outlet 1a of the extruding machine 1 is molded into a fixed form in a molding sphere 2a, to begin with. Then a crosslinking agent is pyrolyzed within a heating device and crosslinking of thermoplastic resin is advanced, a molded body moving within a heating sphere 2b. Then a quantity of 2-50wt.% of the foaming agent is foamed. A partly-foamed molded body 3 having passed through the heating sphere 2b is moved to the next cooling sphere 2c, cooled and its form and a condition of a core are held. Belts 4a, 4b are pressure-contacted with the top and bottom of the partly-foamed molded body 3 and turned in the direction (q) moving against an extruding direction (p). When braking force is applied to the extruded partly-foamed molded body 3 by this brake 4, it becomes that a fluid state is stabilized and unified and the crosslinking is advanced uniformly. |
