Study on high‐solid polyester‐based polyurethane/tinned iron interface

High‐solid polyester polyol resins (low molecular weight) were synthesized and cured by isophorone diisocyanate on tinned iron panels at different temperatures for different times. The resins and polyurethane films were studied by gel permeation chromatography (GPC) and dynamic mechanical analysis (DMA). The polyurethane/tinned iron interfaces were investigated by atomic force microscopy (AFM), the peel test and time‐of‐flight secondary ion mass spectrometry (ToF‐SIMS). The results showed that the polyurethane obtained from a high‐solid resin had higher interfacial roughness and adhesion strength than those from a relatively low‐solid resin. As the curing temperature increased, adhesion strength and the interfacial roughness increased and polyurethane interfacial images changed from rough morphology when cured at room temperature to random hole morphology when cured at 100 °C. The ToF‐SIMS microanalysis showed that no polymeric or metallic groups or segments existed on either the metallic or the polyurethane side.