Antibacterial Properties, Shore Hardness and Chemical Resistance of Epoxy Coatings Containing Finely Ground Secondary Raw Materials for Hygienic Plants

Abstract

Currently fillers for antibacterial layers in hygienic operations are mainly primary raw materials, whose properties are verified and well-known due to their long-term use. However, the use of proper secondary raw materials appears to be a good option from an environmental and economic point of view. This work assesses the possible adverse effects of specially treated secondary raw materials in relation to antibacterial properties, chemical resistance and Shore hardness of the antibacterial coating on an epoxy base (AC-E) providing no physiological damage. This coating reliably eliminates the widest possible range of bacteria and yeasts, has sustained effectiveness, consistent functionality over time, provides permanent protection and is suitable for use in healthcare facilities and food processing plants. Two kinds of transparent waste glass (NaSX, VLG) and two types of waste foundry sand (FSC, FSB) were tested, and all fillers were treated so that particle size was below 0.063 mm, including the reference filler (Dorsilit sand). On the basis of antibacterial resistance tests, Shore hardness and chemical resistance, it was assessed that the tested fillers may be effectively used for antibacterial coatings while maintaining the properties of the reference coating. Within the rapid testing of chemical resistance, the surface microstructure of the antibacterial coating was also examined after long-term exposure to aggressive organic and inorganic liquid media. When adding 30% and 35% of the selected waste fillers, the hardness and chemical resistance of the cured coating did not change. The treated waste fillers tested had no negative impact on the antibacterial properties of the coating and were judged to be appropriate fillers in place of Dorsilit silica sand or glass flakes.