Green Phenolic Resin Hard Manufacturers, Suppliers & Exporters In India. Phenolic resin is a type of synthetic polymer made by combining phenol (a type of aromatic alcohol) with formaldehyde (a simple organic compound). Phenolic resins are widely used in various applications due to their excellent mechanical and thermal properties. When the phenolic resin is hardened, it forms a durable, heat-resistant material. Phenolic resin hardens through a process called curing or polymerization. This involves the reaction between phenol and formaldehyde under specific conditions, often with the addition of a curing agent and heat.