| 摘要 |
PURPOSE:To enable biodegradable resin to cope even with highly foaming without requiring a special chemical foaming agent by a method wherein after raising temperature of a water-containing biodegradable resin granular material together with steam under a pressurized state, the granular material is inflated by opening suddenly, and many inflated granular materials are collected to be integrated. CONSTITUTION:A water-containing biodegradable resin granular material is brought into contact with steam under a pressurized state to raise temperature of the granular material to its softening point or about its melting point. The granular material is inflated by being released suddenly from the state, and many inflated granular materials are collected to integrate the whole thereof. For a manufacturing method, superheated steam is supplied from respective steam tubes 14, 18, and the water- containing biodegradable resin granular material P reaches a conveyor 13 from a hopper 16 via rotary valves 15a, 15b. Its water content is fallen to an exhaust opening 12 under an enclosed state because of a high temperature pressurized condition, and reaches a hermetically sealed space 19 between rotary valves 17a, 17b. When the hermetically sealed space 19 is released, the granular material is suddenly exposed to atmospheric pressure, and foamed by evaporation of the steam in the granular material. |
