Effect of ink transfer on print mottle in shrink films

Abstract

The gravure printing process is considered a pioneer in long run package printing jobs, offering exceptional print quality teamed with high quantities. Shrink films, primarily polyvinyl chloride (PVC) and polyethylene terephthalate-glycol modified (PET-G) are extensively printed using the rotogravure printing process. The intricacies of the printing process and the complex nature of the interactions between the substrate, ink, and printing press, if not studied and controlled, can contribute to unnecessary variation and degradation in print quality. Printability not only can be approximated in the dimensions of densitometry and spectrophotometry, but can also be gauged by print defects such as mottle. This study investigates the effect of process parameters, viz., line screen, ink viscosity, printing speed, and impression roller hardness on print mottle, and explores a way to minimize the same. Design of experiments were generated and analyzed through analysis of variance, main and interaction effects. Furthermore, a regression model was generated to predict the print mottle. The predicted values from the model were in close agreement with the press results. The optimization of process parameters resulted in reduction of print mottle in solid printed areas by 34% and 51% on PET-G and PVC, respectively.

Properties and Colorimetric Performance of Screen-Printed Thermochromic/UV-Visible Fluorescent Hybrid Ink Systems

“…Since all wetting coefficients in the TLC/UVF systems (except TLC-UVF on CB substrate with high wetting coefficient of 12.73 mJ/m 2 ) presented negative values, it can be concluded that the wetting between the layers was generally not complete. This occurrence is generally not favourable, but a negative wetting coefficient in the printing process can decrease the unevenness of the print called mottling, resulting with the improved print quality [43].…”

Surface evaluation and electrochemical behavior of cerium conversion coating modified with silane on magnesium alloy

“…Nevertheless, these cerium conversion coatings have some disadvantages such as the crack of the film and the loose structure, [9] which make the coating providing limited protection to the substrates. In recent years, an intense research is ongoing to develop environmentally and friendly conversion treatment processes to improve the corrosion resistance in corrosive media, including the cerium conversion coatings with alkaline cleaning and activation, [10] phosphate post-treatment, [9,11] water solution gelatin addictive [12,13] and so on. Despite so many researches devoted to the optimization of the cerium conversion coating preparation technology, the problem of the poor adhesion ability has not been resolved yet.…”