Synthesis of Cardanol-Containing Resols for Producing Phenolic Films: Protective Coatings for Wood Composites

This paper investigates synthesis of impregnating phenol–formaldehyde resins in which up to 30 wt % formulation phenol is replaced by cardanol, a plant product. The resulting resins were used to make impregnated paper for laminating the plywood and particle boards. The synthesis and structure of cardanol-containing water-soluble resols were studied by IR spectroscopy and ¹H NMR, and the reactivity of phenol cardanol formaldehyde resins at 80–150°C was studied by differential scanning calorimetry. The optimal amount of cardanol in relation to phenol in the resin structure was determined. It is shown that the introduction of cardanol into the composition of phenol–formaldehyde resins reduces the impregnation time of kraft paper and improves the surface quality and elasticity of the impregnated paper, with the use of such paper making it possible to decrease the water absorption of laminated particle board materials and the emission of formaldehyde.