White inks were prepared with six kinds of titanium dioxide and a polyurethane as a binder. Lamination strength of Extruded Polyethylene/Ink/Nylon Film laminated stock, and peeling strength and internal stress of white ink films were measured.
Results in this study are as follows :
(1) Peeling strength of the ink films and internal stress of the films induced by heating and cooling in laminating process affect lamination strength.
(2) Degree of polymer adsorption on pigments and internal stress of the ink films caused by drying affect peeling strength.
(3) Internal stress shows strong relation to 1% Modulus of the ink films and reduces peeling and lamination strength.
(4) Acid/base amount and particle size of pigments affect polymer adsorption on pigments and internal stress of the ink films caused by drying and heating-cooling processes, which results in the difference in lamination strength,
Of all the pigments evaluated in this study, basic and large particle size titanium dioxide digment provided good lamination strength.
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