ABSTRACT
Polyurethanes can be custom tailored to produce products with properties ranging from soft and flexible to hard and rigid by varying the isocyanate compositions and alcohol functional materials. Aliphatic polyurethanes based on aliphatic isocyanates have improved resistance to degradation from exposure to UV and high-temperature environments; however, aliphatic isocyanates cost two to four times as much as aromatic isocyanates. Ashland Chemical, Inc., wanted to develop a lower cost alternative process for the production of aliphatic isocyanates. Business development focused on producing an aliphatic isocyanate and a family of products. Many nonphosgenation processes for aliphatic and aromatic isocyanates were alternative chemistries for the formation of the isocyanate group after the nitrogen was incorporated onto the desired backbone. One process option investigated in the late 1950s through the 1960s is the addition of isocyanic acid to olefins. This is a direct route to aliphatic isocyanates that could be the basis for a low-cost process.
