| 摘要 |
1,185,329. Paper making. CLUPAK Inc. 25 May, 1967 [27 Feb., 1967], No. 24438/67. Heading D2A. In a press for the compressive shrinkage of paper, the hard surface on to which the web is pressed has a low frictional drag, so that webs of high water content can be treated. In particular, the water-to-fibre ratio is between 1:1 and 3:1, and the frictional drag is not more than 85% of that between a polished chromium surface and a similar web. Suitable surfaces are: fluorocarbon polymer; metal surface plated with chromium, polished, then etched or pitted, e.g. by sandblasting, and coated with a fluorocarbon polymer (such a surface is still usable when the polymer on the peaks of the metal surface has worn away, leaving metal exposed over a minor proportion of the working surface); metal surface plated with chromium treated or applied to give a surface of small closely spaced convex modules, e.g. by polishing a steel surface, then blasting it and finally plating it. Because of its high water content, the treated sheet may be machine glazed. The shrinking apparatus may be, apart from its coefficient of friction, similar to that of U.S. Patent 2,624,245. |
