| 摘要 |
<p>PURPOSE:To enhance the smoothness of the boundary surface between inner layer material and outer layer material by a method wherein heat insulating material is interposed between the inner layer material die and the outer layer material die of a multiple crucible structure so as to thermally separate inner layer material resin from outer layer material resin through the heat insulating material in order to independently change the temperatures of said resins and thus independently control the viscosities of respective resins. CONSTITUTION:In the multi-layered covering device concerned, an inner layer material die 12 and an outer layer material die 13 are thermally shut off from each other by a heat insulating material 15 interposed between both the dies. Accordingly, the temperatures of the resins of respective layers can be controlled independently, resulting in allowing to separately control the viscosities of the respective resins so as to make the boundary surface between the respective layers for multi-layered covering smooth.</p> |
