Wollastonite in Acrylic Paint to Protect Normal and Heat-Treated Spruce Wood Against Coniophora puteana

This study investigates the efficacy of wollastonite-enriched acrylic paint in protecting spruce wood (Picea abies) against the brown-rot fungus Coniophora puteana. Unheated and heat-treated wood samples (185 °C for 4 h) were coated with either plain acrylic paint or wollastonite-enriched acrylic paint and exposed to the fungus. Fungal resistance was evaluated by measuring mass loss (ML) and compression strength parallel to the grain. While conventional acrylic coatings provide a physical barrier against moisture and limited microbial attack, their effectiveness against C. puteana is often insufficient. Our results show that untreated controls lost 23.8% of their mass, whereas plain acrylic paint reduced mass loss only slightly. In contrast, wollastonite-enriched paint significantly decreased ML in both unheated and heat-treated specimens, demonstrating superior antifungal performance. These findings indicate that incorporating wollastonite into acrylic paint enhances fungal resistance, offering a simple, environmentally friendly, and effective surface treatment for spruce wood. This study fills a research gap in the use of mineral additives in acrylic coatings and highlights a practical approach for improving wood durability against fungal decay.