Isocyanate-modified dehydrated castor oil

Esters of dehydrated castor oil fatty acids with polyhydric alcohols like ethylene glycol, propylene glycol, glycerol, pentaerythritol and sorbitol have been prepared. The esters, having hydroxyl value ranging from 78.5 to 167, were reacted with toluene diisocyanate. The scratch hardness and other film properties of the resulting urethanes have been studied. Urethanes obtained from various mixtures of the above esters also have been studied. The best results have been obtained when a mixture of ethylene glycol ester and plenaerythritol ester of dehydrated castor oil fatty acids in the ratio of 4:1 are reacted with one equivalent of toluene diisocyanate. One equivalent of glycerol ester (hydroxyl value 78.5), ethylene glycol ester (hydroxyl value 167), or propylene glycol ester (hydroxyl value 159.4) of DCO fatty acids when reacted with 1.25 equivalent of toluene diisocyanate also gave satisfactory products.