| 摘要 |
<p>Unvulcanised rubber is placed between rubber film by pre-heating the facing sides of the films as the overlapping zone passes above and below heater elements, pref. wedge-shaped, and by extruding the unvulcanised rubber mixture introduced between the films by means of the same heating elements and thereafter subjecting the assembly to a further heat treatment in heated pressure rolls downstream from the heating elements. Adhesives are added to the unvulcanised rubber mixture. The resulting sheets are used as roofing material and are strong.</p> |
