A paper finishing operation consisting of an additional degree of calendering performed on a special machine not connected to the main papermaking machine. The supercalender gives paper a high-gloss finish, the extent of supercalendering determining the extent of the gloss. A supercalender is a vertical alternating stack of hard polished steel and soft cotton (or other resilient material) rolls. The hard roll is pressed heavily against the soft roll, compressing the material. As the paper web passes through this nip, the force generated as the soft roll struggles to return to its original dimensions "buffs" the paper, generating the additional luster and enamel-like finish typical of supercalendered paper. Supercalendering, in enhancing some paper properties, diminishes others in the same way the regular calendering does. (See Calendering.)
|