COMPARATIVE EVALUATION OF THE ALKYD RESINS OF THE COMPOSITE OILS OF SOYBEAN (Ricinus communis) AND CASTOR (Glycine max) SEED OILS WITH CASTOR SEED OIL FOR ALKYD PAINT FORMULATION.

Abstract

The alkyd resins formed from single and composite oils were investigated when used for paint formulation. The soybean and castor seed oils were oil blend were formed in the ratio 1:1 and the alkyd resins for the blend, crude castor and commericial linseed oils were prepared by alcoholysis-polyesterification process. The acid values, quantity of water evolved and colour of the alkyd resins were compared. Three paint samples were formulated using the blended oils alkyd resin (BOARP), castor oil alkyd resin (COARP) and commercial linseed alkyd resin (LOARP). Comparative studies of the drying properties, storage retention and adherence properties were carried out when white BOARP, COARP AND LOARP were applied on metal and steel panels, wood and concrete walls. The percentage oil contents of soybean and castor seeds were 11.73±1.70% and 37.80±0.10% respectively. There were no differences in the colours of both the alkyd resin produced from the blend and linseed as both were dark brown but castor alkyd resin was brown. The time taken for LOARP, BOARP and COARP to become tack free- 2, 6 and ˃48, surface dry-9, 12 and ˃48, dry through-12, 18 and ˃48, and hard dry -16, 24 and ˃48 hours respectively at room temperature. However, all the paints had good adherence properties except the COARP. The study shows that the blended oil can be used as a close alternative for the commonly used and expensive linseed oil. Keywords: Blended castor and soybean oils, unblended castor oil, linseed oil, alkyd paints and curing time.