9 - Habis as Photopolymerization Initiators

Abstract

In 1964, two unrelated events occurred. The work by Cescon, R.L. Cohen, and Dessauer was directed at an improvement in the imaging speed of the dye-based imaging system, then identified as UVI. When it was realized that a higher-speed in the color-formation was difficult to attain by developing a chain-reaction involving the color-formation step, it occurred that a possible route might be a chain reaction involving the deactivation step, in which areas could be made to inhibit color formation. The color-forming system required the availability of plasticizers, and it was reasoned that if such plasticizers could be converted to oligomers that no longer act as such, color-formation could be inhibited. Cescon and Cohen demonstrated that this was possible. In their initial experiments, Cescon and Cohen included the then standard photopolymerization initiators—for example, anthraquinone derivatives—and observed that the system worked as proposed. Cescon found that the system also functioned when the anthraquinone was omitted. Cescon and Cohen concluded that HABIs acted as initiators. Even though the project was terminated because office copy arena became exclusively an opportunity for electrophotography, DuPont applied for a patent that was the first of many that identified HABIs as photopolymerization initiators.