Study On The Preparation And Stability Of Color Ink-jet Printing Paper Coating

On the basis of the relevant literature, the stability and application of color ink-jet printing paper coating which is prepared by silica sol as pigment were investigated in this thesis. At the same time, the performances of prepared silica sol under the normal pressure and applying pressure were discussed.The technics of silica sol preparation by reaction of silicon powder and water through silicon dissolution method under the normal pressure was studied, and some preliminary exploration on preparation of silica sol with pressurized state was also carried out. The results showed that, under the normal pressure, the most effective reaction condition was as follows: when the use level of silicon powder and sodium hydroxide were separately 10g and 0.3g in 200mL water, the reaction was carried out for 8h at 80℃. While under the applying pressure, it could be desirable to carry out at 0.5MPa and 160℃, silicon powder15g and sodium hydroxide 0.4g in 200mL water, then silica sol with particle size above 100nm and good monodispersity could be obtained.According to the colloid chemistry theory, using the protective effect of macromolecular solution on colloidal sol, the homemade polyacrylamide (PAM) was added in coating system to control colloidal particle's conglomeration of low solids content coating. The appropriate molecular weight of PAM, best type of PVA and effects of all components'addition on system's stability were investigated. By the orthogonal experiment, the optimum formulas of low solids content coating were determined as follows: silica sol 100g, PAM (appropriate molecular weight 1.11×104)0.6g, PVA(type 235) 3g, color-fixing agent (type IJ-450) 30g, PE wax emulsion 0.7g.The PAM with super low molecular weight was prepared by aqueous solution polymerization containing a little organic solvent. The influence on molecular weight of PAM of amount of solvent, initiation and chain-transfer agent was studied.Different kinds of composition of high solids content coating such as silica sol, polyvinyl alcohol and cationic additive, and different coating weight were investigated with orthogonal experiment method. Silica sol was also characterized by IR and TEM. The results showed that when silica solⅡ, PVA235, Poly-DMDAAC and 10-12g/m2 as coating weight were adopted, the properties of paper could reach a better degree.The high solids content coating was formulated in pilot plant with domestic silica sol SW-30, PVA235 and Poly-DMDAAC as main composition. The product with low cost is up to standard.