Fatty acids from linseed, safflower and tall oils were converted to the corresponding isocyanates by two methods. In the first method linseed and safflower fatty acids were converted to the acid chloride either with thionyl chloride or oxalyl chloride and the acid chlorides were converted to the azide which was finally decomposed into the isocyanate. Yields of isocyanates were related to the method used to prepare the parent acid chlorides, the oxalyl chloride procedure giving higher yields of isocyanates. Loss in unsaturation from acids to isocyanates was slight. The tall oil isocyanates were prepared in high yields via the phosgene method, thus, fatty acids to nitriles to amines, to the amine hydrochloride which were then reacted with phosgene. The isocyanates prepared by this procedure contained one more CH, group than those prepared via the first mentioned method. The infrared spectra of all isocyanates were essentially identical.
Herstellung von Isocyanaten aus Lein-, Safflor-und Tallol-Fettsauren Lein-, Safflor-sowie Tallol-Fettsauren wurden nach zwei Methoden in die entsprechenden Isocyanate ubergefuhrt. Nach einem dieser Verfahren wurden zunachst die Lein-und Safflorol-Fettsauren entweder mit Thionylchlorid oder Oxalylchlorid zu den Saurechloriden umgesetzt, die nach ihrer Uberfdhrung in die Azide und anschlieDender Zersetzung die Isocyanate ergaben. Die Ausbeute der Isocyanate war abhangig von der Methode zur Herstellung des Saurechlorids. Die Oxalylchlorid-Methode lieferte hohere Ausbeuten an Isocyanat. Die Abnahme des Gehaltes an Doppelbindungen war bei der Umwandlung der Sauren zu den Isocyanaten gering. Tallol-Isocyanate wurden in hoher Ausbeute nach der Phosgen-Methode erhalten, wobei die Fettsauren iiber Nitrile und Amine in Aminhydrochloride iibergefiihrt wurden, die man mit Phosgen umsetzte. Die nach dieser Methode erhaltenen Isocyanate enthalten eine CH,-Gruppe mehr als die, die nach der erstgenannten Methode hergestellt wurden. Die IR-Spektren aller Isocyanate waren im wesentlichen identisch.
Within recent years the coatings industry has adopted several families of urethane coating systems. T . C. Palton et ali-3 and H. M . M e t z 4 have described these systems in some detail. One member in this family is the "urethane oil" or "one-can urethane coating". These are esters of polyols, more functional than glycerol, and drying or semidrying oil fatty acids, cross-linked via aromatic di-and polyisocyanates. These compositions form films by oxidation-polymerization. Several reports describe these film formers in detail 5-9.
The films of the drying oil modified polyurethanes described above have improved performance characteristics with respect to tensile strength, hardness, drying time and chemical resistance when compared to similar ~