A new ultraviolet protective agent of the intercalation compound of aminobenzoic acid esters (UV absorber) and synthetic mica (Inorganic Layered Compound)

The interaction between a sodium-type synthetic mica (Na-TSM), a material of reactive layered compounds which exhibit characteristic light scattering, and some aminobenzoic acid derivatives which act as UV absorbing agents (UV absorber), was investigated. Due to the observed elongation of interlayer spacing (increase in the d-value) by X-ray diffraction analysis, it was found that the powdered form of 4-aminobenzoic acid ethyl ester (4- ABE) interacts with Na-TSM, and can be immobilized in the interlayer space of Na-TSM. Consequently, an intercalation compound of 4-ABE and Na-TSM was obtained. The formation of the intercalation compound of 4-ABE and Na-TSM was accelerated by heat processing, particularly at temperatures exceeding the melting point of 4-ABE. When 2-aminobenzoic acid methyl ester (2-ABM) in liquid form at room temperature was used instead of 4-ABE, the intercalation compound of 2-ABM and Na-TSM was formed in a similar manner to that of 4-ABE and Na-TSM. The heat processing again accelerated the formation of the intercalation compound of 2-ABM and Na-TSM. Interestingly, a difference in the formation behavior of intercalation compounds between 4-ABE and 2-ABM was observed. The intercalation compound of Na-TSM and 4-ABE or 2-ABM showed efficient UV absorption in the UV(B) and UV(A) wavelength regions. Therefore, application of a layered compound of Na-TSM and 4-ABE or 2-ABM as a novel UV screening system is promising.