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Ink Removal From Polyethylene Packaging Films:
Correlation to Surface Morphology and Chemistry
Gehan Eltanany, Master’s Candidate, Chemical Engineering,
and Dale Teeters, Ph.D.

In order to recycle commercial plastic packaging films the ink printed on the films must be removed so that recycled products will be clear and have good physical properties. The object of this study is to understand the process of ink removal so that packaging films can be better recycled.

The basic phenomenon of ink adhesion and removal has been studied by looking at the surface of polyethylene films that have been subjected to a ceramic bead impact ink removal process where printed polyethylene (PE) films, zirconium silicate beads, and water were agitated in a laboratory shaker. Atomic force microscopy (AFM) images show that the PE packaging film surfaces studied in this work are composed of a “shish-kebab”⁽¹⁾ lamellar structure. AFM images of the ink coatings show ink emulsion particles of approximately 190 nm in diameter which have coalesced upon drying to form the printed ink surface. The surface structure of the PE film before ink removal was found to have lamella of approximately 200 x 500 nm. Upon impact of the ceramic beads on the polyethylene films, the surface lamella appear to be deformed to lamella that are now approximately 500 x 500 nm in size. Surface Fourier Transform Infrared Spectroscopy (FTIR) data show that the surface crystallinity of the PE film decreases with the impact ink removal process. Correlations between the direction of the polyethylene lamella on the surface and ink removal appear to exist. A proposed mechanism for ink removal will be discussed.

 (1). K. D. Jandt, M. Buhk, M. J. Miles and J. Petermann, Polymer, 35, 2458 [1994].