Evaluation of Effective Parameters on Rheological and Mechanical Properties of Automotive Plastisol Coatings Reinforced with Nano Silica Using Taguchi Method

Plastisols are the liquid suspension compositions containing polyvinyl chloride resin (PVC), plasticizers and extenders, with various applications such as automobile coatings as seam sealers, which converts to the flexible material using heat. Rheological and mechanical properties of these compositions are related to the type of reinforcing materials. Reinforcing materials like nano silica has been used for improvement of different properties of these compositions. In this research, using Taguchi method and optimized model calculated from experimental design, effect of PVC type, particle size of calcium carbonate, type of plasticizer and silica particle size on mechanical and rheological properties like viscosity, strength, hardness and morphology were investigated. Particle size was evaluated using scanning electron microscopy and the results were analyzed. Based on variance analysis, it was found that for reaching to the optimum process conditions and highest strength of plastisol coatings, K-value for PVC resin must be about 70, mesh size of calcium carbonate about 1000, type of plasticizer was dibutyl phthalate (DBP) and nano silica particle size was about 200 nm.