• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.38 no.5 s.118
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• pp.47-53
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• 2006

To meet the ever increasing quality demand of coated papers and duplex boards, the local gloss variation and print unevenness must be avoid. To do this, surface roughening phenomenon which affects local gloss and print unevenness was investigated. In this study, the effect of roughness and densification of sheet obtained at various calendering conditions on surface roughening was examined. To evaluate the calendering effect properly we introduced a new value of roughening index by moisture for evaluation of surface roughening. Caliper and roughness of sheet decreased with increasing of calendering temperature and pressure, and the remarkable reduction of those properties occurred at the temperature around Tg. Roughening index increased when the amount of water increased and calendaring temperature and pressure increased. And as the sheet became denser by calendering, the roughening index increased to some extent. But roughening index by moisture is the lowest for sheet precalendered at higher temperature condition. When the surface of calendered sheet is rougher, there is more roughening of surface. The severe condition of calendering made the roughening index by moisture small.