The influence of surface tension on wetting in dampening solution and sustainability of printing: A review

Abstract

Offset is defined as a printing technique using a system of two-fluids (ink + dampening solution) that requires a constant monitoring and a balancing system due to the physical-chemical features of the process. Ink and dampening solution on the printing plate surface should not be intergraded during the chemical interaction. Image and non-image areas on the plate surface can be separated from each other only through the interaction of dampening solution and ink. The dampening solution is responsible for the wetting of non-image areas on a printing plate, and are applied to the entire plate. In the wetting process, the amount of the dampening solution on the plate should be at the lowest level. This can be provided only by lowering the surface tension of the dampening solution. Thus, quality printing results, such as edge sharpness, high color intensity and high print gloss are achieved with a small amount of wetting on the printing plate surface. In this study, the wetting of the printing plate surface is investigated under the effects of surface tension of dampening solution and its angle of contact with the printing plate and current studies related to the subject are reviewed and discussed.

Surface analysis of polymer films for wettability and ink adhesion

“…Generally, a surface with a low surface energy will cause poor wetting, and therefore result in a high contact angle. When a liquid droplet is set on a smooth solid horizontal surface, it may spread out over substrate and the contact angle will approach zero if complete wetting takes place 6,31 . Thus, the better the wettability of the solid surface (Figure 2).…”

“…Contact angle measurement of liquid droplets is a widely accepted method for surface analysis of polymeric materials related to surface energy, wettability, adhesion and absorption 34‐37 . The wetting and solid wettability is usually illustrated with a small liquid droplet resting on a flat horizontal solid surface, from which the angle at the three phases in contact can be determined 31,33 . The contact angle is measured as the angle between the tangent line at the point of contact of the drop to the solid surface and the horizontal line of the surface 38 .…”

“…When a drop of liquid is dripped onto a solid substrate surface, the better the water drop on the surface wets the surface, the smaller the contact angle 31 . Low contact‐angle values demonstrate a tendency of the water to spread and adhere to the surface, whereas high contact‐angle values show the surface's tendency to repel water 33 .…”

The use of natural (Pinus pinaster) resin in the production of printing ink and the printability effect

“…Today, consumers prefer products obtained from renewable energy resources instead of petroleum-based resources. 14,15 Inclination of countries toward renewable resources and encouragement of the use of these resources is important for the ecosystem, environment, and for sustainable resource management. Several printing ink producers tend for VOC-free, more biodegradable, more bio-compatible, more renewable, and sustainable inks with the growing demand for natural resources in recent years.…”

“…A renewable resource is a resource, which can be used repeatedly and replaced naturally. Today, consumers prefer products obtained from renewable energy resources instead of petroleum‐based resources 14,15 . Inclination of countries toward renewable resources and encouragement of the use of these resources is important for the ecosystem, environment, and for sustainable resource management.…”