| 摘要 |
Method for preparing a structure of various layers of the same shape consisting of different layers of viscous liquid and natural or synthetic sheets employs containers with rectangular open tops and a flat bottom with side walls, a conveyor with vertical transport surface with straight and a curved track sections, and a device for supplying viscous liquid above the conveyor. The process has several stages in which a series of closely adjacent containers moves through the straight part at a continuous speed. Viscous liquid is metered evenly over the cross-section of the containers moving underneath to form a layer in them. The speed of the filled containers is increased to ensure unimpeded passage through the curved sections of the track. A sheet of natural or synthetic material is laid over the whole of the surface of the liquid layer in each container at such a place and time that the layer has become of uniform thickness due to gravity. The above operations are repeated at suitable intervals. Specifically, the viscous liquid is a polyvinyl alcohol acetal reaction solution containing an aldehyde, a mineral acid as a catalyst and starch as a foaming agent. |
