CHARACTERISTIC AND PREDICTION MODEL OF VERTICAL DENSITY PROFILE OF FIBERBOARD WITH 'PRETREATMENT - HOT PRESSING' UNITED TECHNOLOGY

摘要

In order to manufacture fiberboard with different vertical density profile (VDP) and establish predicted model of vertical density profile, the "pretreatment-hot pressing" united technology was used to study the effect of pretreatment parameters on the sandwich layer temperature and the shape factor of VDP. The results showed that the humidification to surface of mats could eliminate the procuring layer and the effect of target density on the shape of VDP could be neglected under united technology. Increasing moisture content, preheating temperature and preheating time could enhance the temperature of sandwich layer after pretreatment process, through which could decrease the surface density deviation and sandwich layer density deviation, increased homogeneity sandwich layer thickness rate and the VDP is converted from "V" shape to "U" shape,uniform in turn. So the ideal fiberboards with "U" shape (U-FBs) and homogeneity fiberboard (H-FBs) could be produced through regulating and controlling "pretreatment-hot pressing" united technology. The VDP predicted model under united technology built in the study had a very strong predictive ability.