Rheocin Castor oil based Sud Chemie Waxes & Paraffin >> Castor Oil derivative (HCO-wax) SEALANT Additives for Caulks and Sealants Rheocin® Castor oil based powdered thixotrope designed for aliphatic (low polarity) systems. Imparts ideal balance of sag control and flow. Requires shear and processing temperature range. Castor oil based powdered thixotrope. Used as a rheology modifier in caulks and sealants. Designed for aliphatic (low polarity) systems. Offers very good balance of sag control and flow. Requires shear and processing temperature range.