Surface analysis of polymer films for wettability and ink adhesion

Abstract

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.

Mechanical and barrier properties of flexible packaging materials after the flexo printing process

“…In the case of non-polar materials that include the tested polypropylene, the surface of the foil to be printed is pretreated in order to increase the polarity of the surface. This surface treatment of the foil (mainly by the corona process through electrical discharge) achieves the effect of surface oxidation, and the existing non-polar structure is converted into polar groups (Aydemir et al, 2021). This significantly improves the print quality, adhesion and chemical affinity, which are a condition for the optimal process of printing, laminating and coating (Aydemir et al, 2021).…”

“…The determination of the surface tension of solids is based on the fact that the shape of a drop of a liquid on a solid body depends on the surface tension of the materials in contact. The surface tension calculation is based on the Young-Dupre equation, where σ s = surface free energy, σ sl = interfacial tension between the liquid and solid, σ l = surface tension of the liquid (Krüss Application Report, 2014): corona process through electrical discharge) achieves the effect of structure is converted into polar groups (Aydemir et al, 2021). T adhesion and chemical affinity, which are a condition for the optim (Aydemir et al, 2021).…”

Drying methods of the printing inks

“…Various liquid materials in printing such as inks, varnishes, lacquers, and adhesives contain high ratios of water. (Aydemir, Altay & Akyol, 2021). Water and other polar solvents are easily heated by microwave energy.…”

Priprava i karakterizacija poli(metil-metakrilatnih) kompozita s nanocelulozom

“…Polarnost površine od osobite je važnosti za ambalažne polimerne materijale, gdje su uobičajeno potrebni ispis slika i grafičko označavanje proizvoda. 31 Stoga se hidrofobni polimeri poput polietilena moraju dodatno modificirati, što ponekad zahtijeva i dodatnu opremu u postrojenjima.…”