Castor polyols for urethane foams

Summary A systematic investigation of some 21 castor polyols as base materials for preparing urethane foams was carried out. Prepolymers were prepared both from individual castor polyols and from mixtures of them with an anhydrous castor oil. Foams formed from these prepolymers were checked for shrinkage on cure, density, and modulus. From the wide range of results obtained it is evident that castor polyols can serve as effective urethane components. Aside from serving as major polyols for reaction with di‐isocyanates, they can also be used as modifying polyols a) to speed up prepolymer preparation, b) to adjust prepolymer viscosity to any required degree, c) to minimize loss of modulus on humid aging, and as cross‐linking centers with negligible loss of foam modulus. Details covering the preparation of a nonshrinking, semi‐rigid, light‐weight urethane foam based on an 85% anhydrous castor oil/15% epoxidized castor oil mix are outlined in the article.