| 摘要 |
PURPOSE:To improve sound absorbing characteristics and heat insulating characteristics and to correspond to complicated material quality by continuously changing specific gravity in the thickness or surface direction of a layer. CONSTITUTION:The temp. of the wall part of a recessed mold 7 is set to a temp. range from the softening temp. of the granular material being the raw material received in the closed space formed by the recessed mold 7 and a protruding mold 8 to the pyrolysis temp. thereof, usually, to a temp. range of 150 - 240 deg.C and the temp. of the wall part 13 of the protruding mold 8 is set to temp. lower than that of the wall part 11 of the recessed mold 7, for example, about the softening temp. of the granular material being the raw material, usually, 70 - 180 deg.C. The granular material brought into contact with the high temp. wall part 11 of the recessed mold 7 is melted to become a high specific gravity layer, in other words, a fused layer 2 at last and this layer 2 changes from air permeability to air impermeability according to a degree of fusion. Since the temp. of the wall part 13 of the protruding mold 8 is lower than that of the high temp. wall part 11, the granular material from the wall part 13 to the fused layer 12 does not reach a perfect flowable state but welded at contact parts in a semi-flowable state and a porous layer 3 is formed. |
