Paper Machine Press Section Influence
Paper machine press section have an important influence on paper structure and properties, so what’s the influence of paper machine press section for paper sheet?
Press Section Influence For Paper Sheet
1. The first important effect of pressing on paper sheet structure is to reduce the paper sheet porosity. Generally, regardless of pulp beating degree, the paper porosity decreases with the increase of pressing force.
2. Pressing can cause the decrease of paper thickness. In addition, increasing the pressing force can increase the bonding between the fiber, is helpful for increasing paper tightness, while reducing the folding resistance of paper sheet.
3. The press operation makes the fiber structure more tightly, paper sheet combined area more increase. From the optical physics of paper sheet, the paper opacity is derived from the scattering of the fiber uncombined area in paper sheet. The press operation increases the combined area of paper sheet, thus reducing paper opacity.
4. It is generally believed that the two sides of paper are formed in paper machine wire section, the two sides difference will reduced after entering press section. But in actual press operation, also can cause a certain paper sheet two sides difference.
5. Press operation will also have some negative impact on paper sheet, mainly cause the fiber keratinization. Before drying, the wet paper is pressed to a higher dry degree, which will aggravate the pulp fiber keratinization. The pulp fiber keratinization will influence the strength of the wet broken paper fiber after pressing, and the quality decay of recycled fiber can be affected.