Are there any formulations for flexographic inks for polyethylene, which do not contain nitrocellulose ?
Suitable alternatives for nitrocellulose include acrylic and vinyl resin as well as chlorinated rubber and resin derivatives. Inks based on polyamide resins are, however, probably the best for printing on polyethylene.
Here is a guide formulation :
Polyamide resin ( 50% solution in an alcohol/hydrocarbon mixture, molecular weight 2000-7000) = 33 %To ensure good adhesion of the printed image, the polyethylene surface should be pretreated either by corona or by application of a flame across the surface.
Maleinised ester resin = 5 %
Polyethylene compound = 8 %
Pigment ( titanium dioxide, coloured pigments ) = 45 %
Isopropanol =6 %
Solvent Naphtha = 3 %