Study On The Application Of Microfibrillated Celllulose On Surface Sizing Of Digital Printing Paper

Microfibrillated cellulose(MFC)is a new type of nano-cellulose functional material with degradable properties.With stable performance,uniform performance,film formation performance and simple producing process,it has a large aspect ratio,crystallinity,specific surface area and water retention value.This paper will study the application of MFC as a surface sizing agent to improve the printability of digital printing paper.This paper used MFC,Cassava starch,SAE and PVA for single-component sizing and compound sizing.The effects of MFC on the viscosity of the sizing liquid,Cobb value,dynamic permeability,contact angle,physical properties,surface resistivity and volume resistivity were studied.The improvement effects of MFC on laser and inkjet digital paper printing suitability were analyzed.The result of research shows that the addition of MFC caused the surface resistivity of the paper to decrease,the volume resistivity to increase and the color density to increase for laser digital printing paper.The dynamic permeability and smoothness of paper had a great influence on printing quality.When the ratio of MFC and Cassava starch was 100:4,the dynamic permeation parameter of Ct was 5.817s and Ci was 4.6%.The smoothness was 327.89 s.The superior ink dot roundness and line quality were obtained compared to the unsized paper and the single MFC sized paper.Meanwhile,the Cobb value,dynamic penetration,contact angle and smoothness greatly affected the reproduction of printing performance for ink-jet digital printing paper.When the ratio of MFC and Cassava starch was 100:1,the Cobb value is 20.5,the dynamic permeation parameter of Ct was 9.249 s,the Ci was 8.5%,the T95 was 7.708 s and the Tmax was 2.449 s,the static contact angle was 86°.The smoothness was 281.63 s.The CMYK solid color density of inkjet paper were increased by 93.8%,62.1%,27%,and 76.6%respectively compared to unsized paper.The text quality was significantly improved.The dot roundness was improved by 7.7%,the color bleeding degree was reduced by 94.1%and the line quality was improved by 29.4%.The CMYK solid color density of inkjet paper were increased by 83.8%,44%,17.7%,and 49.1%respectively compared to the single MFC sized paper.The text quality was significantly improved,the color bleeding degree was reduced by 93.7%and the line quality was improved by 30.5%compared to the single MFC sized paper.After MFC and surface sizing starch are compounded,good synergistic effect and suitable viscosity of the sizing liquid were obtained from this study.The surface properties,infiltration characteristics and electrical properties of sizing layer could be well controlled,which was beneficial to the improvement of comprehensive printing performance of digital printing paper.