Preparation and Formulation of Transparent Coating for Protection and Durability of Packaging Printing in Metal Cans

With the advent and development of a variety of products with metal containers (such as wax, spray, paint and tea cans, etc.), it is necessary for consumer information to be inserted and printed on the body of these metal cans. To protect, polish and beauty and also to avoid getting lost the printing of packaging on the body of metal cans, the transparent and colorless coating on the metal cans printing, including highlights in the packaging of these metal containers. Synthetic resins are transparent coating that are used as connectors for color constituents and printing on a variety of metal packaging.In this study, three types of transparent coatings have been formulated, including short oil alkyd resin (containing a mixture of soybean oil and coconut oil with two types of hardeners (amine hardeners: melamine formaldehyde resins and urea formaldehyde).Type I transparent coating: short oil alkyd resin with melamine formaldehyde resin (as hardener);Type II transparent coating: short oil alkyd resin with urea formaldehyde resin (as hardener);Type III transparent coating: short oil alkyd resin with one-to-one mixture of melamine formaldehyde + urea formaldehyde resin. It indicates that the curing (baking) reaction of each of these transparent coatings was completed at 175 °C (with a convection oven equipped with a complete air convection flow) in 20 minutes. Mechanical tests (hardness, impact and cupping test), quantitative test (solid percentage) and viscosity test were performed for all three types of transparent coatings to introduce the best formulas for transparent coatings. Experimental results showed that in the resin / hardener weight ratio, 75% by weight of short alkyd oil and 25% by weight of hardeners provide access to the best transparent coating. For all three types of transparent coatings with the best quality, in this study infrared spectroscopy (FTIR) and scanning electron microscopy (SEM) analysis were performed.