| 摘要 |
Structural units, and method and apparatus for making the same. Two webs are advanced in spaced parallel predetermined paths. A foam material is deposited on the upper surface of the lower web and foamed to form a foam layer. An intermediate web is applied onto the foam layer. An intermediate layer of sound- or fire-retarding material is applied onto the intermediate web, and the space between the intermediate layer and the upper web has foam material introduced thereinto and converted into a foam layer, whereby to obtain an elongated structural laminar unit consisting of the various layers and webs which adhere to one another. |
