Industrial & Engineering Chemistry Research, Vol.53, No.49, 19216-19227, 2014
UV Curing Paint on Hybrid Films Modified with Plasticizer Diisodecyl Adipate Applied on Tinplate: The Effects of Curing Temperature and the Double Layer
Hybrid film coatings obtained by the solgel process are based on two important reactions: hydrolysis and condensation. Their kinetics varies with the curing temperature, which modifies the intrinsic gel properties, with a possible increase in the layer thickness and improving the barrier effect against corrosion on tinplate, a material widely used for packing. The same effect can be also obtained by increasing the number of layers; however, if there is not a good adherence between the layers, delamination could occur, which would affect the protective effect. Thus, the objective of this work is to coat tinplate with a hybrid film obtained from a solgel process constituted by the alkoxide precursor tetraethoxysilane (TEOS) and 3-trimethoxysilylpropyl methacrylate (TMSM), with addition of cerium nitrate (0.01 M) and diisodecyl adipate (2%) to the sol formulation. These coatings were applied in single and double layer films by a dip-coating process on tinplates and cured at different temperatures (60 and 90 degrees C). The hybrid films with better performance were coated with a UV-cured paint. Films were characterized by scanning electron microscopy. The hydrophobicity of the samples was analyzed by contact angle. Fourier transform infrared spectroscopy measurements were performed to characterize the chemical structures of the films. Hybrid films were characterized concerning the electrochemical behavior from the open circuit potential and electrochemical impedance. The aforementioned systems were painted and then evaluated by mechanical testing adhesion and flexibility. Hybrid films with better performance were UV-cured. Results showed that both the double layered hybrid film cured at 90 degrees C and the monolayer hybrid film cured at 60 degrees C showed the best electrochemical performances. Also, the latter showed the best performance in the mechanical tests with UV curing inks applied.