Stable Ultraviolet Light Absorbers

Abstract

It has been found that many substituted benzophenones are very effective as ab sorbing agents for ultraviolet light. Unlike most organic compounds which have been used for this purpose, this new class of absorbers is quite resistant to degradation. The physical properties and uses of these ultraviolet absorbers are discussed in detail.

The ultraviolet component of solar radiation extends from 400 down to about 290 mμ. A major objective in the development of stable organic absorbers has been to achieve a maximum of ultraviolet absorbing power with a minimum of visible color.

A variety of interesting applications have been found for these absorbers. They may be used in protective coatings or filters to protect substrates from ultraviolet light. They are usually quite effective as stabilizers when incorporated in ultraviolet sensitive materials. There are many potential applications of ultraviolet absorbers in the textile industry. They could be incorporated in fabric coatings or in finishes applied to yarns or fabrics that are known to degrade in outdoor exposure because of ultraviolet light. They can improve markedly the light fastness of those dyes which are faded by ultra violet light. Some of the problems involved in these applications are discussed.