Cationically modified boehmite for ink jet paper coatings.

摘要

Color intensity, color stability, and image resolution are three important criteria for high-quality, color ink jet prints. Much research work has been done and a large number of patents have been issued for improving the color intensity, color stability, and image resolution by attempting to improve each component involved in the ink jet printing process: the printer, the ink, and the receiving media. Background literature includes the development of waterfast ink systems, forced drying systems for the printer, and new materials for paper coating formulations. However, color stability, and especially waterfastness of color prints, is still a big concern for those engineering ink jet printing. Surface modification of the materials used in media coating formulations is a technique by which dye adsorption properties and thus waterfastness may be improved.;Commercial boehmite (γ-AlOOH) was modified with cationic silane coupling agents which chemically bonded permanent positive surface charges onto the boehmite surface. Paper coatings made with cationically modified boehmites provided a stronger, more thermodynamically favorable interaction between anionic dye molecules and cationic boehmite surface while significantly improving the dye adsorption capacity, as compared with unmodified surfaces. In addition, color intensity was improved through adsorption of dye molecules onto the outermost surface of the coating. Excellent color stability resulted because of this stronger interaction. A dye adsorption model was developed to illustrate critical factors affecting printing quality. Two simple, quantitative spectrophotometric methods were developed to evaluate waterfastness of color prints produced with dye-based ink jet inks.