RESEARCH ON THE RELATIVE HUMIDITY OF PAPER AND ITS AFFECTING FACTORS
In order to obtain high-quality printing products, the printing house requires the paper produced by a paper mill to have the same equilibrated relative humidity (Eq. RH*) as the printing condition. Generally, the RH* of paper including roll-paper/ sheet-paper means the air relative humidity within the paper at a certain temperature. This article considers the definition of RH* and factors that affect its value in the papermaking process. The RH* in the process of papermaking was continuously measured with a temperature humidity sensor. During such a unit the operations are coating, calendaring, rewinding, cutting, hand sorting and packing. Results were graphed to show trends in RH*. The results indicated that the RH* of paper was a concept different from the other physical character indexes of paper such as bursting strength, tearing strength and so on. The RH* just shows the character of roll paper/sheet-paper at a certain temperature. The main affecting factors of the RH* were the moisture of paper, the temperature of paper and the testing instrument. The moisture of paper is proportional to the RH*. However, the temperature of paper is inversely proportional to the RH*. The change of the temperature and relative humidity of the surrounding may cause the local deformation of roll-paper and sheet-paper, and the RH* of the paper will not be affected. In order to regulate the RH* of paper, the paper mill may reduce or increase the temperature of dryers to change the moisture of paper, but this method has up to this point not been sufficient to accurately control the RH*.
relative humidity relative humidity of paper temperature humidity sensor coated paper roll-paper sheet-paper affecting factors
Chang Hengyuan Han Qing
Shaanxi University of Science and Technology, Xi’an,710021, China
国际会议
广州
英文
1649-1651
2010-11-08（万方平台首次上网日期，不代表论文的发表时间）