印刷用纸孔隙结构分析

目的印刷用纸的孔隙结构是影响印刷品质量及纸质食品包装材料安全性的重要因素,分别用硅油饱和法和Image J图像处理法,对国内不同厂家的8种纸样的孔隙率和表面孔隙率进行了测定。方法用硅油代替以往的苯与无水乙醇测定8种纸样的孔隙率,用Image J图像处理法对8种纸样的扫描电子显微镜(SEM)图进行二值化处理,通过阈值以及参数的设定,计算得到了其表面孔隙率。结果采用饱和法测得各纸样的孔隙率为40.20%~59.52%,平行样误差小于6%,且纸样经过饱和及烘干处理后,纤维之间并没有发生离散现象;采用图像处理法测得各纸样的表面孔隙率为9.90%~23.80%。结论纸(纸板)的孔隙率与其厚度成正比,表面孔隙率与表面处理情况有关,其中纸样3和纸样8的表面孔隙率值较低,分别为10.10%和9.90%,可能的原因是其表面孔隙被涂布层覆盖所致。

Porous Structure Analysis of Printing Paper and Board

The porous structure of printing paper is an important influencing factor for the print quality and safety of food packaging paper materials. This work aimed to study the porosities and surface porosities of paper samples collected from 8 different domestic paper factories using the silicone oil saturation method and Image J image processing method. The porosities of the 8 paper samples were determined using silicone oil instead of the traditional benzene and absolute ethanol. Binarization processing of the SEM images of the 8 paper samples was conducted using the Image J image processing method, and the surface porosities were calculated by setting of threshold values and parameters. The porosities of the paper samples measured by the saturation method were between 40.20% and 59.52%, and the errors among parallel samples were lower than 6% . After saturation and drying, no discrete phenomenon occurred between the fibers of the paper samples. Meanwhile, the surface porosities of the paper samples determined by the image processing method were between 9.90% and 23.80% . The porosities of paper (board) samples werepositively correlated with their thickness, while the surface porosities were associated with the surface processing. The surface porosities of samples 3 and 8 were relatively low, which were 10.10% and 9.90% respectively, and the possible cause was the coverage of their surface pores by the coating.