| 摘要 |
A process for making sheets of plastic material of high optical quality by casting the plastic material or a mixture of its components on a flat, moving substrate is disclosed. According to the invention, a stable pocket of material is formed on the moving substrate upstream of the zone at which the plastic material flows from the casting apparatus onto the substrate. The material in the pocket moves in predetermined paths and leaves the pocket to form the lower portion and the edges of the sheet. A direct stream of material is simultaneously formed downstream of the zone of delivery of the plastic material onto the substrate in a tangential relation to the meniscus, to form the upper portion of the sheet. |
