Effect Of The Sealing Process On Wettability and Wear Properties Of Anodized Aluminum Lithographic Plates

Anodic coatings produced on a typical aluminum plate were sealed, using four aqueous media. The wear behavior and wettability of the anodized aluminum surface sealed in sodium silicate solution differ markedly from those sealed in other media. These results are interpreted on the basis of different mechanisms of sealing. Sealing treatments, especially with sodium silicate solution, increase the hydrophilicity of an anodized aluminum surface, and thereby help ensure optimum differentiation of image and non-image areas. Improvement in hydrophilicity by sealing unfortunately sacrifices wear resistance, and hence useful plate life. These opposing effects must be taken into account when manufacturing a lithographic printing plate.