Preparation and characterization of waterborne alkyd-amino baking coatings based on waste polyethylene terephthalate

The recycling of polyethylene terephthalate (PET) is the most attractive method for PET waste management because it not only decreases the load on landfill space, but also provides opportunities for reducing the use of raw petrochemical products. Therefore, in this investigation, neopentyl glycol is used for alcoholysis of waste PET, and glycolyzed PET product was applied for preparation of the waterborne alkyd resin. Furthermore, the waterborne alkyd-amino baking coatings were prepared from the waterborne alkyd based on glycolyzed waste PET and melamine formaldehyde resin and applied on tinplate. The waterborne alkyd-amino resin films showed excellent adhesion, balanced hardness and flexibility, high gloss and outstanding chemical resistance except for alkali resistance owing to hydrolysis of ester bonds.