Synthesis of ester curable alkali phenolic resins with the addition of natural phenolic substances

Phenol-formaldehyde resins are used as binders to hold sand grains together in the casting industry and to form durable molds and cores for casting molten metal at high temperature. This thesis, which aims to evaluate sustainable raw materials instead of phenol based on fossil sources to synthesize phenolic resin which have alkali properties that can harden after adding esters at desired time. In different synthesis steps of the currently and highly using Alfanol A38 coded foundry resin that belongs to Çukurova Kimya Inc. Co. , instead of phenol, calcium lignosulfonate and resorcinol were included separately and together in condensation polymerization in the range of weight 5%, 10% and 20%. Different types of modifications have been tried to make natural materials more suitable for the reaction and the effect of the modification has been discussed. For the characterization of the resins obtained at the end of the synthesis processes, pH, viscosity, free formaldehyde, solid matter amount determination and FT-IR and SEM analyzes were performed. By designing demo steel casting, ÇKE Alfanol A 38 and synthesized two new resins with ideal price performance ratio and compatable product were cast into four cores and their direct application performances were evaluated. In the alfanol resin synthesis which is examined as two steps, 15% lignosulphonate was substituted for phenol in the first step, and this resin can be cured in 12-18 min. gives an average strength performance of 20 N/cm2 at the end of 1 hour, reaching 40 N/cm2 compression strength at the end of 24 hours as A 38. 5% lower raw material cost was obtained in lignosulphonated resin. Resorcinol was added in Part 2 and a higher addition of KOH was made to balance its acidic character. The desired gel time values were achived in resorcinol modified resin and it was determined that modification caused an increase in average performance. The metal / core interfaces of the cores of the four different resins obtained after casting were compared and their performances under high temperature were tested at the application.