1. Field of the Invention
The present invention relates to a process for treating a compound having epithio structure for disposal, and more particularly to a process for treating for disposal an unused portion of a mixture comprising a compound having epithio structures and a catalyst for curing the compound obtained in a process comprising casting and polymerizing the mixture to produce an optical material, such as a plastic lens, a prism, an optical fiber, an information recording substrate and a filter.
2. Description of the Related Arts
The present inventors have discovered novel compounds having epithio structures which provide optical materials having useful properties as optical materials, i.e., a small thickness, a small chromatic aberration, a refractive index of 1.7 or more and an Abbe number of 35 or more as described in the specifications of patent application for these compounds (Japanese Patent Application Laid-Open No. Heisei 9(1997)-110979 and Japanese Patent Application No. Heisei 8(1996)-5797). These compounds having epithio structures and compounds having epithio structures which are similar to these compounds (hereinafter, both referred to as compounds having epithio structures) show large reactivity in the presence of a curing catalyst. However, no process for mildly solidifying an unused portion of these compounds for disposal have been developed. Compositions containing a compound having episufide structures also show large reactivity in the presence of a curing catalyst. For example, when such compositions are left standing in a completely adiabatic system, abnormal polymerization takes place to generate a large amount of heat and to form bubbles and fumes. Therefore, to dispose these compounds and compositions, the compounds and the compositions cannot be left standing but must be divided into small portions and kept under control at a low temperature. Disposal in a large amount has been actually impossible. Moreover, compositions containing a compound having epithio groups contain a large amount of sulfur and there is the possibility that toxic gases such as carbon monoxide, sulfur oxide and hydrogen sulfide are generated in the abnormal polymerization. Thus, development of a process for mildly solidifying these compositions for disposal has been desired.