| 摘要 |
A large thin web having a coherent crystal morphology throughout its extent is made on a continuous basis by drawing a meniscus of the web material from a hot melt thereof onto a heated support surface which moves relative to the melt so that the liquid is distributed as a thin liquid film over that support surface. The moving support surface advances the film progressively past a chiller which establishes a chill zone at the surface of the film which cools the film material at an isothermal front or boundary therein to a temperature below the melting point of the material so that the material solidifies. Also, a crystal seeding bar is located at the chill zone which is brought into contact with the film just ahead of the front so that when the film solidifies in the chill zone it assumes the crystal morphology of the seeding bar. The solidified film that is peeled from the support surface constitutes the finished web, while new material drawn from the melt is added to the support surface upstream from the chill zone so that the process is continuous. Method and means for controlling the process are also disclosed, as are various articles and structures made from such webs. Also disclosed are means for depositing additional layers of material to the web while preserving a compatible crystal morphology throughout the entire plural-layer structure. |
