Dual functions of Cu(NO3)2 as antifungal and colour stabilizer for coating paint film consisting of chlorophyll

Purpose This paper aims to discuss about the benefits of Cu(NO 3 ) 2 applied in coating paint film that consists of plant extract from Cassia Alata . Cu(NO 3 ) 2 has been added to the coating paint film as a colour stabilizer and as an antifungal property by forming a zone of inhibition towards fungal growth. Design/methodology/approach The coating paint film resin consists of a mixture of poly (methyl methacrylate) (PMMA) and acrylic polyol. The coating paint film’s performances were observed in terms of visible optical and physical appearance. Findings When exposed to the fungus Trichoderma Sp ., a zone of inhibition of 208 mm 2 was formed around the coating paint film and therefore it gave the coating paint films an antifungal property. The commission internationale de l’éclairage (CIE) L*a*b* colour coordinate system was used to identify the colour changes in the coating paint film and it was found that the addition of Cu(NO 3 ) 2 to the coating paint film has a better colour stability, as it has a lower standard deviation (STD) value of 6.46 than the pure dye coating paint film of 8.95. The gloss of coating paint film with the addition of Cu(NO 3 ) 2 was found to be have a more stable gloss based on its smaller STD value at both angles taken at 20° and 60°. Research limitations/implications The Cassia Alata plant has different amount of antifungal properties based on location its growth. Practical implications The coating paint film developed in this study is suitable for indoor applications. Originality/value The plant extract from the Cassia Alata gives the coating paint film an antifungal property.