| 摘要 |
PURPOSE:To produce a foamed surface layer having a high foaming degree and excellent heat-insulating property by a method wherein a foamable coating material is coated on the inside surface of a hollow mold, and after introducing a parison into the mold and closing the mold, air is blown into the mold while simultaneously transferring a part of the heat contained in a hollow body to the foamable coated film. CONSTITUTION:The foamable liquid coating material of polyurethanebased type or the like is coated on the cavity surface of the hollow metallic mold 1, 1 having a cavity in the shape of a bellowslike duct, the parison is then introduced into the cavity under the condition where the foamable coated film 6 is heated and foamed, the mold is closed and air is blown into the mold through a blowing-in port 4. As a result, the parison 3 is inflated and closely contacted with the coated film 2 to form the hollow body 5, while part of the heat contained in the body 5 is transferred into the film 2 to accelerate the foaming of the film 2. When the internal pressure of the body is reduced, the foamed surface layer 2' in which the size and the number of the foams are increased toward the inside surface of the layer 2' is obtained. USE:Air-conditioning duct for vehicles and the like. |
