The interaction between inks and substrates is critical during printing. Adhesion of the ink film is determined by the reciprocal interactions of polar and nonpolar (dispersive) components between polymer films and inks. The greater the similarity between the polar and dispersive components of inks, coating and substrates, the better the wetting and adhesion on the surface of printing substrate. Various liquid materials in printing such as inks, varnishes, lacquers, and adhesives contain high ratios of water. The highly polar nature of water makes the interaction of these materials unsuitable with predominantly disperse polymer surfaces. Some films with polyolefin structure, especially polypropylene, and polyethylene, are nonpolar and cannot form strong bonds with ink, varnish, or lacquer coatings due to their chemical structure. Increasing surface energy components overcomes the poor wetting and adhesion on polymer surfaces. In this review, the topics of water contact angle measurement and determination of surface energy, surface tension, and using sessile drop method for the wettability and ink adhesion of polymer films are surveyed. Information on structural and chemical processes was given that assists in obtaining wettable film surfaces. Recommendations were made for good adhesion and printability based on surface treatment methods and ink modification.

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Introduction: Printing inks oil selection is related to the desired nature of the varnish in the ink production. Petroleumderived mineral oils and vegetable oils can be used in offset inks. Methods: In this study, the behaviors of vegetable-and mineral oil-based inks on uncoated and coated paper surfaces were investigated in terms of printability. Solid tone test prints were done with offset printing of these inks. Print gloss of the printed samples was measured and a light fastness test was implemented on these samples in order to determine the resistance to fading. Absorption behavior and contact angles of the ink-printed films on the test papers were measured with the sessile water drop method depending on time, and surface energies were calculated. Results: On both paper types, linseed-soybean oil-based vegetable ink gave the highest brightness value. The lowest print gloss results on the paper were obtained from soybean oil-based inks. The lowest color change was recorded with mineral oil-based inks on gloss-coated papers. According to the ink-film-surface relation, when the contact angle is high, surface energy decreases and the absorbency of the ink-film is lower. Conclusions: In this study, the behaviors of vegetable-and mineral oil-based inks on different paper surfaces, and the effect on the quality of printability as well as differences, have been evaluated, taking environmental and health factors into consideration.

Light fastness, in its broadest sense, is the resistance of colours to fading under the influence of a light source. Light fastness is one of the most important physical, and therefore visual, properties sought in both pigments and in the inks. Artificial and natural light causes most pigments to fade resulting in colour change. The light fastness of inks is important especially in the packaging and advertising industries. The posters and advertisements hung on the billboards used especially in outdoor advertising, printed product packaging and other printed products exposed to sunlight require high degree of light fastness. In this study, light fastness and factors affecting the resistance of the colour to the light were investigated and suggestions were made regarding high light fastness in terms of printability.

One of the keys to improving print quality is to experimentally characterize the paper surface, structure and printability to obtain quality control mechanisms. In multi-color prints, determining the differences in the acceptance of the next color ink by the surface of the paper or the ink film that was previously printed is important for print quality. The criteria, such as ink setting, adhesion, color, gloss and density, in the printing process, depend on the wettability and absorbency of the paper. The surface structure of the paper is the most important factor in determining the hydrophobic properties. In this study, wetting and absorption dynamics of the printed partially hydrophobized paper surface were investigated. The aim was to measure the effect of the printed ink film on the wetting (surface free energy) and liquid absorption behavior of the paper. Liquid absorption changes on printed/unprinted paper surfaces were measured by the sessile drop method, using a contact angle-measuring device. The surface energies of the papers were calculated and evaluated according to the surface contact angle of the droplet.