| 摘要 |
A versatile, multiple-slot, dual cavity, slide/extrusion hopper for assembling and coating a composite layer comprising a plurality of highly uniform, superposed compositions, and a method for determining the dimensions of the hopper are disclosed. The hopper is suitable for photographic applications and other applications requiring highly uniform layers. The hopper is versatile in that it can accommodate coating compositions that range from Newtonian to substantially shear thinning and in that fewer than the total number of elements may be supplied; the slide offsets between elements are suitable for both merging layers and for the top layer alone. The height of the secondary slot is preferably greater than the height of the primary slot. The method provides optimal cross-sectional shapes for the cavities. Versatility is achieved without greatly increasing the height or thickness of the elements. A formula is provided which gives a straightforward and useful way to determine and scale versatile designs and thereby eliminate much experimentation and reduce the number of coating hoppers required.
|
