Applying SiO2 nanoparticles to epoxy coating used in food cans to reduce migration of aggressive agents

Epoxy coatings are commonly used as interior coatings for food cans and have good mechanical properties, adhesion and flexibility, and protect food cans against corrosion. These coatings contain bisphenol A diglycidyl ether(BADGE) as well as bisphenol A(BPA) units as residues in the structure, which poses a risk of migration of these derivatives into canned foods and has dangerous effects. In this research, silica nanoparticles were added into the formulation of epoxy can coating and its effect on the migration of BPA and BADGE derivatives was evaluated using inductively coupled plasma (ICP) and high-performance liquid chromatography (HPLC) testing methods. Also, mechanical and chemichal properties as well as coatings resultant safety were studied. Observations clarified that the hardness(scratchability) of the coatings increased by adding 0.5 wt% SiO2 nanoparticles. The migration rate of SiO2 was negligible and the migration rate of BPA was lower than the acceptable limit mentioned in the Commission Regulation (EU 10/2011) and decreased by about 3% with the addition of 0.3 wt% SiO2 nanoparticles. The migration rate of BADGE and its hydrated and hydrochloride derivatives in food simulants was lower than the acceptable limit in (EC) No. 2005/1895. The lowest migration rate of BADGE and its hydrated derivatives (BADGEs) into acidic and alcoholic food simulants was related to the epoxy coating containing 0.3% by weight of SiO2 nanoparticles, which was reduced by 6 and 22%, respectively, compared to the pure epoxy coating sample, and the migration rate of hydrochloride derivatives into the alcoholic simulant was reduced by 6.8%