INFLUENCE OF COATING COMPOSITION ON WEB RELEASE IN HIGH-SPEED FILM TRANSFER COATING

The study was conducted to establish base parameters for future studie s of one-sided film transfer coating. Simple, unoptimized coatings con taining U.S. clay or ground calcium carbonate (GCC) were studied to ev aluate the impact of coating pigment on the runnability of the paper w eb and the coating color at high machine speeds (1200-2000 m/min). Res ults demonstrate that the coating color composition and the machine sp eed influence the point of web release during the film transfer proces s. GCC's lower aspect ratio translates to a wetter coating layer exiti ng the transfer hip-and thus a longer web release-at a given level of coating film on the transfer roll. Increasing the solids content of GC C (from 63% to 66%) reduced the distance before web release. A compara ble increase in solids content for the clay pigment had no effect on w eb release.